,transcriber's ,notes ,obvious spelling errors have been corrected4 ,i have not reconciled the variety of spellings of names and other words4 ,obvious factual errors1 typographical errors1 discoveries made after #ahib1 and contemporary 7#bjjh7 theories and use of words are noted in the text within square brackets4 ,i have not researched and checked every assertion by the author4 ,this book was published #e years before discovery of the electron4 ,see the labored and completely inaccurate explanations of aurora and energy1 atomic4 ,the author and his contemporaries were like fifteenth century sailors4 ,they had a good idea of their latitude and direction 7,ampere1 ,kirkoff1 ,maxwell1 ,gauss1 ,faraday1 ,edison1 '''71 but only the vaguest notion of their longitude 7nuclear structure1 electrons1 ions74 ,altitude 7special relativity1 quantum theory7 was not even imagined4 ,some relevant dates3 ,franklin's ,kite--#ageb ,faraday's ,law of ,induction--#ahca ,maxwell's ,equations--#ahfa ,edison's ,phonograph--#ahgg ,edison's light bulb--#ahgi ,edison's first ,,dc power station--#ahhb ,michelson-,morley experiment disproving ether--#ahhg ,hertz demonstrates radio waves--#ahhh ,westinghouse first ,,ac power station--#ahia ,this book--#ahib ,discovery of the electron--#ahig ,marconi radio signals cross the ,english ,channel--#ahig ,first ,vacuum ,tube--#aijd ,special ,relativity1 photo-electric effect explained with photons--#aije ,general ,relativity3 space-time dilation and curvature--#aiae ,confirmation of general relativity's prediction of the deflection of starlight by the ,sun--#aiai ,discovery of the proton--#aibj ,quantum theory--#aibf ,discovery of neutron--#aicb ,first transistor--#aidg ,soviet satellite ,luna measures solar wind--#aiei ,edward ,m4 ,purcell explains magnetism with special relativity--#aifc ,purcell's explanation of magnetism as a result of ,lorentz contraction of space along the direction of a current is a welcome relief from the convoluted descriptions in this book4 ,mathematical notation is rendered using programming notation4 ,power--,exponential2 ,a#c means ,a cubed 99 ,multiply _/ ,divide ,add - ,subtract 7 7 ,precedence--,perform before enclosing expression #b;,e#f ,scientific ,notation 7#b1jjj1jjj7 ,a --------------------- #d4deb ,x #ajab ,x t is rendered as ,a _/ 7 #d4deb;,e#ab 99 t 7 ,where the rendering of a mathematical expression is in doubt1 an image of the original text is included4 ,here are some definitions absent from the text4 ,foucault currents4 ,eddy currents4 inspissate ,to thicken1 as by evaporation4 riband ,ribbon4 sapotaceous ,order ,sapotaceae of trees and shrubs1 including the star apple1 the ,lucuma1 or natural marmalade tree1 the gutta-percha tree 7,isonandra71 and the ,india mahwa1 as well as the sapodilla1 or sapota1 after which the order is named4 ,don ,kostuch1 ,,ms1 ,electrical ,engineering4 ,end ,transcriber's notes4 ,,works ,,of ,t4 ,o',,conor ,,sloane1 ,a4,m41 ,e4,m41 ,ph4,d4 ,,arithmetic ,,of ,,electricity ,a ,,manual ,,of ,,electrical ,,calculations ,,by ,,arithmetical ,,methods4 ,third ,edition4 ,illustrated4 #a4jj4 ,it is very useful to that class of readers to whom ,algebra is a comparatively unknown quantity1 and will meet its wants admirably4--,electrical ,world4 ,,electricity ,,simplified4 ,a ,,popular ,,treatment ,,of ,,the ,,subject4 ,illustrated4 #a4 #jj4 ,we especially recommend it to those who would like to acquire a popular idea of the subject4--,electric ,age4 ,,electric ,,toy ,,making4 ,,for ,,amateurs4 ,,including ,,batteries1 ,,magnets1 ,,motors1 ,,miscellaneous ,,toys1 ,,and ,,dynamo ,,construction4 ,fully ,illustrated4 #a4jj4 ,,the ,,standard ,,electrical ,,dictionary4 ,a ,,popular ,,dictionary ,,of ,,words ,,and ,,terms ,,used ,,in ,,the ,,practice ,,of ,,electrical ,,engineering4 ,,by ,t4 ,o',,conor ,,sloane1 ,a4,m41 ,e4,m41 ,ph4,d4 ,,new ,,york ,,george ,d4 ,,hurst ,,publisher ,copyright #ahib by ,,norman ,w4 ,,henley ,,co4 ,,preface ,the purpose of this work is to present the public with a concise and practical book of reference1 which it is believed will be appreciated in this age of electricity4 ,the science has expanded so much that the limits of what may be termed strictly a dictionary of the present day would a few years ago have sufficed for an encyclopedia4 ,it follows that an encyclopedia of electricity would be a work of great size4 ,yet a dictionary with adequate definitions1 and kept within the closest limits by the statement of synonyms1 and by the consigning of all the innumerable cross-references to a concise index will be far more than a mere dictionary in the ordinary sense of the term4 ,duplication of matter is to be avoided4 ,this makes many definitions appear short4 ,yet1 by the assistance of the reader's own general knowledge1 and by referring to the very complete index1 almost any subject can be found treated in all its aspects4 ,there are exceptions to this statement4 ,so much has been done in the way of mechanical detail1 so many inventions in telegraphy and other branches have sprung into prominence only to disappear again1 or to be modified out of recognition1 that to embody descriptions of many ingenious and complicated apparatus has been absolutely impossible for want of space4 ,a word as to the use of the book and the system of its construction may be given here4 ,each title or subject is defined once in the text4 ,where a title is synonymous with one or more others the definition is only given under one title1 and the others appear at the foot of the article as synonyms4 ,it may be that the reader is seeking the definition of one of these synonyms4 ,if so a reference to the index shows him at once what page contains the information sought for4 ,the use of an index in a work1 necessarily of an encyclopedic form1 will be appreciated by all users of this book4 vi ,,preface4 ,where a title embraces several words1 all orders of the words will be cited in the index4 ,to make the operation of finding references easy this rule has been carried out very fully4 ,it is customary to regard electricity as a growing science4 ,it is unquestionably such1 but the multiplication of terms and words is now not nearly so rapid as it has been1 and the time for the compiling of a work of this character seems most propitious4 ,it is hoped that the public will indulgently appreciate the labor it has entailed on all concerned in its production4 ,,symbols ,,and ,,abbreviations4 adj4 ,adjective4 v4 ,verb4 q4v4 ,which see4' _/ ,a mark of division1 as ,a_/,b1 meaning ,a divided by ,b4 4_/4 ,the same as above4 ,transcriber's note3 _/ will be substituted for this divide symbol4 ,a mark of equality1 meaning is equal to4 ,x ,a mark of multiplication1 meaning multiplied by4 ,transcriber's note3 99 will be substituted for this divide symbol4 ,fractional exponents indicate the roots expressed by their denominators and the powers expressed by their numerators4 ,thus1 ,a#a_/b means the square root of ,a2 ,a#a_/c means the cube root of ,a2 ,b#c_/b means the square root of the cube or third power of ,b4 ,the use of powers of ten1 as #ajaj1 #ajaa1 as multipliers1 will be found explained at length in the definition ,ten1 ,powers of4 vii ,,standard ,,electrical ,,dictionary ,a4 ,abbreviation for anode1 employed in text relating to electro-therapeutics4 ,it is sometimes written ,an4 ,abscissa4 ,in a system of plane co-ordinates 7see ,co-ordinates7 the distance of any point from the axis of ordinates measured parallel to the axis of abscissas4 ,in the cut the abscissa of the point a is the line or distance a c4 ,fig4 #a4 ,,axes ,,of ,,co-,,ordinates4 ,absolute4 adj4 ,in quantities it may be defined as referring to fixed units of quantity1 and it is opposed to relative1 which merely refers to the relation of several things to each other4 ,thus the relative resistance of one wire may be n times that of another2 its absolute resistance might be #e ohms1 when the absolute resistance of the second wire would be #e_/n ohms4 ,a galvanometer gives absolute readings if it is graduated to read directly amperes or volts2 if not so graduated1 it may by calibration q4 v4 be made to do practically the same thing4 #h ,,standard ,,electrical ,,dictionary4 ,absolute ,measurement4 ,measurement based upon the centimeter1 gram1 and second4 7,see ,centimeter-,gram-,second ,system47 ,absolute ,temperature4 ,temperature reckoned from absolute zero 7see ,zero1 ,absolute74 ,it is obtained by adding for the centigrade scale #bgc1 and for the ,fahrenheit scale #dei1 to the degree readings of the regular scale4 ,absorption1 ,electric4 ,a property of the static charge4 ,when a ,leyden jar is being charged it dilates a little and the capacity increases1 so that it can take a little more charge for a given potential difference existing between its two coatings4 ,this phenomenon occurs with other static condensers1 varying in degree with the dielectric4 ,with shellac1 paraffin1 sulphur and resin1 for instance1 the absorption is very slight2 with gutta-percha1 stearine1 and glass1 the absorption is relatively great4 ,the term is due to ,faraday4 ,iceland spar seems almost or quite destitute of electric absorption4 ,a4 ,c4 ,c4 ,symbol of or abbreviation for anodic closure contraction q4 v4 ,acceleration4 ,the rate of change of velocity4 ,if of increase of velocity it is positive2 if of decrease1 it is negative4 ,it can only be brought about by the exercise of force and is used as the measure of or as determining the unit of force4 ,it is equal to velocity 7,l_/,t7 imparted1 divided by time 7,t72 its dimensions therefore are ,l_/7,t#b74 ,the c4 g4 s4 unit of acceleration is one centimeter in one second4 ,transcriber's note3 ,the unit of acceleration is centimeters per second per second4 ,accumulator4 7a7 ,a term sometimes applied to the secondary or storage battery4 7,see ,battery1 ,secondary47 7b7 ,see ,accumulator1 ,electrostatic 7c7 ,see ,accumulator1 ,water ,dropping4 7d7 ,see ,wheel1 ,barlow's ,accumulator1 ,electrostatic4 ,two conducting surfaces oppositely placed1 and separated by a dielectric and arranged for the opposite charging of the two surfaces1 constitute an accumulator1 sometimes termed a condenser4 ,as this arrangement introduces the element of a bound and of a binding charge1 the electrostatic capacity of such is greater than that of either or of both of its component surfaces4 ,the thinner the dielectric which separates the conducting surfaces1 and the larger the surfaces the greater is the capacity2 or the less will be the potential difference which a given charge will establish between its two coatings4 ,the nature of the dielectric also determines its capacity4 7,see ,capacity1 ,specific ,inductive47 #i ,,standard ,,electrical ,,dictionary4 ,fig4 #b4 ,,sir ,,william ,,thomson',s ,,water-,,dropping ,,accumulator4 ,accumulator1 ,water ,dropping4 ,this is also known as ,sir ,william ,thomson's ,water-,gravity ,electric ,machine4 ,it is an apparatus for converting the potential energy of falling water drops1 due to gravity1 into electric energy4 ,referring to the illustration1 ,g represents a bifurcated water pipe whose two faucets are adjusted to permit a series of drops to fall from each4 ,c and ,f are two metallic tubes connected by a conductor2 ,e and ,d are the same4 ,two ,leyden jars1 ,a and ,b1 have their inner coatings represented by strong sulphuric acid1 connected each to its own pair of cylinders1 ,b to ,d and ,e1 and ,a to ,f and ,c4 ,the outer coatings are connected to earth1 as is also the water supply4 ,one of the jars1 say ,a1 is charged interiorily with positive electricity4 ,this charge1 ,c and ,f1 share with it1 being in electric contact therewith4 ,just before the drops break off from the jet leading into ,c1 they are inductively charged with negative electricity1 the positive going to earth4 ,thus a series of negatively excited drops fall into the metal tube ,d1 with its interior funnel or drop arrester1 charging it1 the ,leyden jar ,b1 and the tube ,e with negative electricity4 ,this excitation causes the other stream of drops to work in the converse way1 raising the positive potential of ,f and ,c and ,a1 thus causing the left-hand drops to acquire a higher potential4 ,this again raises the potential of the right-hand drops1 so that a constant accumulating action is kept up4 ,the outer coatings of the ,leyden jars are connected to earth to make it possible to raise the potential of their inner coatings4 ,in each case the drops are drawn by gravity into contact with objects similarly excited in opposition to the electric repulsion4 ,this overcoming of the electric repulsion is the work done by gravity1 and which results in the development of electric energy4 #aj ,,standard ,,electrical ,,dictionary4 ,acidometer4 ,a hydrometer or areometer used to determine the specific gravity of acid4 ,they are employed in running storage batteries1 to determine when the charging is completed4 7,see ,areometer47 ,aclinic ,line4 ,a terrestrial element2 the locus on the earth's surface of no inclination of the magnetic needle2 the magnetic equator4 7,see ,magnetic ,elements47 ,acoustic ,telegraphy4 ,the system of sound-reading in telegraphy1 universally used in the ,morse system4 ,the direct stroke of the armature of the electro-magnet and its back stroke disclose to the ear the long and short strokes1 dots and lines1 and long and short spaces as produced by the dispatcher of the message4 ,in the ,morse system a special magnet and armature is used to produce the sound called the sounder2 in other systems1 e4 g41 ,steinheil's and ,bright's apparatus1 bells are used4 7,see ,alphabets1 ,telegraphic47 ,acoutemeter4 ,a ,hughes audiometer or sonometer applied to determining the quality of a person's hearing 7,see ,hughes' ,induction ,balance1--,audiometer74 ,the central coil by means of a tuning fork and microphone with battery receives a rapidly varying current tending to induce currents in the other two coils4 ,telephones are put in circuit with the latter and pick up sound from them4 ,the telephones are applied to the ears of the person whose hearing is to be tested4 ,by sliding the outer coils back and forth the intensity of induction and consequent loudness of the sounds in the telephones is varied4 ,the position when the sounds grow so faint as to be no longer audible1 gives the degree of delicacy of the person's hearing4 ,by using a single telephone the same apparatus affords a means of testing the relative capacity of the right and left ears4 #aa ,,standard ,,electrical ,,dictionary4 ,actinic ,rays4 ,the rays of light at the violet end of the spectrum2 also the invisible rays beyond such end1 or the ether waves of short periods which most strongly induce chemical change4 ,actinism4 ,the power possessed by ether waves of inducing chemical change1 either of decomposition or of combination4 ,the violet and ultra-violet end of the spectrum of white light1 generally speaking1 represent the most highly actinic rays4 ,actinometer1 ,electric4 ,properly an apparatus for measuring the intensity of light by its action upon the resistance of selenium4 ,a current produced by fixed electro-motive force passing through the selenium affects a galvanometer more or less according to the intensity of the light4 ,it is more properly an electric photometer4 ,the term has also been applied to a combination of a thermo-electric pile and galvanometer1 the light falling on the pile affecting the motions of the galvanometer4 ,action1 ,local4 7a7 ,the wasteful oxydation of the zinc in a galvanic battery due to local impurities and variations in the composition of the zinc4 ,these act to constitute local galvanic couples which cause the zinc to dissolve or oxydize1 without any useful result4 ,amalgamation of the zinc prevents local action4 ,chemically pure zinc is also exempt from local action1 and can be used in an acid battery without amalgamation4 7,see ,amalgamation47 7b7 ,the same term has been employed to indicate the eddy or foucault currents in dynamo electric machines4 7,sec ,current1 ,foucault47 ,activity4 ,the rate of doing work2 the work done per second by any expenditure of energy4 ,the activity of a horse-power is #eej foot lbs4 per second1 or #gdf volt-coulombs per second4 ,the practical electric unit is the volt-ampere1 often called the watt4 7,sec ,energy1 ,electric47 ,adapter4 ,a screw coupling to engage with a different sized screw on each end2 one of the uses is to connect incandescent lamps to gas-fixtures4 ,a4 ,d4 ,c4 ,abbreviation for ,anodic ,duration ,contraction1 q4 v42 a term in electro-therapeutics4 ,adherence1 ,electro-magnetic4 ,the adherence between surfaces of iron due to elcctro-magnetic attraction4 ,it has been applied to the driving-wheels of an engine and rail1 whose grip is increased by such action4 ,in one method a deep groove was cut around the wheel which was wound with a magnetizing coil4 ,thus one rim becomes a north and the other a south pole1 and the rail completing the circuit acts as the armature4 ,such an arrangement prevents a wheel from sliding4 ,electro-magnetic adherence has also been employed to drive friction gear wheels4 ,in one arrangement the two wheels are surrounded by a magnetizing coil1 under whose induction each attracts the other1 developing high adherence between their peripheries4 #ab ,,standard ,,electrical ,,dictionary4 ,fig4 #c4 ,,electro-,,magnetic ,,car ,,wheel4 ,fig4 #d4 ,,electro-,,magnetic ,,friction ,,gear4 ,admiralty ,rule of ,heating4 ,the ,british ,admiralty specifications for the permissible heating of dynamos4 ,it holds that at the end of a run of six hours no part of the dynamo under trial shall show a rise of temperature greater than #aa ,c4 7#bj ,f47 above the temperature of the air surrounding it4 ,this is thought to be a very stringent and unnecessarily high requirement4 ,aerial ,conductor4 ,an electric conductor carried from housetops1 poles1 or otherwise so as to be suspended in the air1 as distinguished from an underground or submarine conductor4 ,affinity4 ,the attraction of atoms and in some cases perhaps of molecules for each other by the force of chemical attraction4 ,when the affinity is allowed to act or is carried out1 a chemical change1 as distinguished from a physical or mechanical change1 ensues4 ,thus if sulphur and iron are each finely powdered and are mixed the change and mixture are mechanical4 ,if slightly heated the sulphur will melt1 which is a physical change4 ,if heated to redness the iron will combine with the sulphur forming a new substance1 ferric sulphide1 of new properties1 and especially characterized by unvarying and invariable ratios of sulphur to iron4 ,such change is a chemical one1 is due to chemical affinity1 is due to a combination of the atoms1 and the product is a chemical compound4 #ac ,,standard ,,electrical ,,dictionary4 ,agir ,motor4 ,the ,anderson and ,girdlestone motor4 ,the term agir is made up from the first portions of each name4 ,agonic ,line4 ,the locus of points on the earth's surface where the magnetic needle points to the true north2 an imaginary line determined by connecting points on the earth's surface where the needle lies in the true geographical meridian4 ,such a line at present1 starting from the north pole goes through the west of ,hudson's ,bay1 leaves the east coast of ,america near ,philadelphia1 passes along the eastern ,west ,indies1 cuts off the eastern projection of ,brazil and goes through the ,south ,atlantic to the south pole4 ,thence it passes through the west of ,australia1 the ,indian ,ocean1 ,arabia1 the ,caspian sea1 ,russia and the ,white sea to the ,north ,pole4 ,it crosses the equator at #gj ,w4 and #ee ,e4 approximately4 7,see ,magnetic ,elements47 ,synonym--,agone4 ,transcriber's note3 ,the file ,earth,declination#aeijaiij4;gif provided by the ,u4,s4 ,geological ,survey 7http3_/_/www4usgs4gov7 is an animation of the declination of the entire earth4 ,air4 ,air is a dielectric whose specific inductive capacity at atmosphere pressure is taken as #a4 ,it is practically of exactly the same composition in all places and hence can be taken as a standard4 ,when dry it has high resistance1 between that of caoutchouc and dry paper4 ,dampness increases its conductivity4 ,it is a mixture of oxygen and nitrogen1 with a little carbonic acid gas and other impurities4 ,its essential composition is3 ,oxygen3 7by weight7 #bc4ad 7by volume7 #ba ,nitrogen3 #gf4hf #gi ,the specific inductive capacity varies for different pressures thus3 ,approximate vacuum 74#jja mm41 4#jjjd inch7 #j4id 7,ayrton7 7 #e mm4 1 4#b inches 7 #j4iihe 7,ayrton7 #j4iiida 7,boltzman47 ,the specific gravity of air under standard conditions #ae4e ,c 7#fj ,f47 and #gfj mm4 barometric pressure 7#cj inches7 is taken as unity as a standard for gases4 ,transcriber's note3 ,argon accounts for #j4icdj4 ,it was discovered in #ahid1 two years after this book4 ,air-,blast4 7a7 ,in the ,thomson-,houston dynamo an air-blast is used to blow away the arc-producing spark liable to form between the brushes and commutator4 ,it is the invention of ,prof4 ,elihu ,thomson4 ,the air is supplied by a positive action rotary blower connected to the main shaft1 and driven thereby4 ,the wearing of the commutator by destructive sparking is thus prevented4 ,a drum ,h ,h is rotated1 being mounted on the axis ,x of the dynamo4 ,as it rotates the three vanes are thrown out against the irregular shaped periphery of the outer case ,t ,t4 ,the arrow shows the direction of rotation4 ,the air is thus sent out by the apertures a a4 ,o is the oil-cup4 7b7 ,the air-blast has also been used by ,prof4 ,thomson in experiments with high frequency currents of high potential4 ,by directing a blast of air against a spark discharge between ball terminals of an alternating current1 the nature of the current was changed and it became capable of producing most extraordinary effects by induction4 #ad ,,standard ,,electrical ,,dictionary4 ,fig4 #e4 ,,air ,,blower ,,for ,,thomson',s ,,dynamo4 ,air ,condenser4 ,a static condenser whose dielectric is air4 ,the capacity of an air condenser in farads is equal to ,a _/ 7 #d4deb;,e#ab 99 t 7 in which ,a is the area of one sheet or sum of the areas of one set of connected sheets in square inches and t is the thickness of the layer of air separating them4 ,a convenient construction given by ,ayrton consists in a pile of glass plates ,p separated by little bits of glass ,f of known thickness1 three for each piece4 ,tin-foil ,t is pasted on both sides of each piece of glass and the two coatings are connected4 ,the tin-foil on each second plate is smaller in area than that on the others4 ,the plates are connected in two sets1 each set comprising every second plate4 ,for ,a in the formula the area of the set of smaller sheets of tin-foil is taken4 ,by this construction it will be seen that the glass does not act as the dielectric1 but only as a plane surface for attachment of the tin-foil4 ,posts ,e ,e keep all in position4 ,one set of sheets connects with the binding post ,a1 the other with ,b4 ,the capacity of any condenser with a dielectric of specific inductive capacity i is given by the formula3 7 i 99,a#a 7 _/ 7 #d4deb;,e#ab 99 t#a 7 ,the air condenser is used for determining the value of i for different dielectrics4 ,fig4 #f4 ,,air ,,condenser4 #ae ,,standard ,,electrical ,,dictionary4 ,air ,gaps4 ,in a dynamo or motor the space intervening between the poles of the field magnet and the armature4 ,they should be of as small thickness1 and of as extended area as possible4 ,their effect is to increase the magnetic reluctance of the circuit1 thereby exacting the expenditure of more energy upon the field4 ,they also1 by crowding back the potential difference of the two limbs1 increase the leakage of lines of force from limb to limb of the magnet4 ,air ,line ,wire4 ,in telegraphy the portion of the line wire which is strung on poles and carried through the air4 ,air ,pump1 ,heated4 ,it has been proposed to heat portions of a mercurial air pump to secure more perfect vacua1 or to hasten the action4 ,heating expands the air and thus produces the above effects4 #af ,,standard ,,electrical ,,dictionary4 ,air ,pump1 ,mercurial4 ,an air pump operated by mercury4 ,the mercury acts virtually as the piston1 and the actuating force is the weight of the column of mercury1 which must exceed thirty inches in height4 ,there are many types4 ,mercurial air pumps are largely used for exhausting incandescent lamp chambers4 7,see ,geissler ,air ,pump1--,sprengel ,air ,pump47 ,air ,pumps1 ,short ,fall4 ,a mercurial air pump in which the fall of mercury or the height of the active column is comparatively small4 ,it is effected by using several columns1 one acting after the other4 ,a height of ten inches for each column suffices in some forms4 ,enough columns must be used in succession to make up an aggregate height exceeding #cj inches4 ,fig4 #g4 ,,burglar ,,alarm ,,switch ,,or ,,circuit ,,breaker4 ,fig4 #h4 ,,burglar ,,alarm ,,switch ,,or ,,circuit ,,breaker4 ,alarm1 ,burglar4 ,a system of circuits with alarm bell extending over a house or apartments designed to give notice of the opening of a window or door4 ,as adjuncts to the system the treads of the stairs are sometimes arranged to ring the bell1 by completing a circuit when trod on4 ,door mats are also arranged to close circuits in like manner4 #ag ,,standard ,,electrical ,,dictionary4 ,for doors and windows switches are provided which are open as long as the door or window is closed1 but which1 on being released by opening the door or windows1 automatically close the circuit4 ,the circuit includes an alarm bell and battery1 and the latter begins to ring and continues until stopped1 either by the closing of the door or by a switch being turned4 ,the connections are sometimes so contrived that the reclosing of the door or window will not stop the bell from ringing4 ,the cuts show various switches for attachment to doors and windows4 ,it will be seen that they normally keep the circuit closed1 and that it is only open when pressure1 as from a closed door1 is brought upon them4 ,in the case of a door a usual place for them is upon the jamb on the hinge side1 where they are set into the wood1 with the striking pin projecting1 so that as the door is closed the pin is pressed in1 thus breaking the circuit4 ,sometimes the connections are arranged so as to switch on the electric lights if the house is entered4 ,special annunciators showing where the house has been entered are a part of the system4 ,a clock which turns the alarm on and off at predetermined hours is also sometimes used4 ,the circuits may be carried to a central station or police station4 ,one form of burglar alarm device is the ,yale lock switch4 ,this is a contact attached to a ,yale lock which will be closed if the wrong key is used1 completing a circuit and ringing a bell4 ,fig4 #i4 ,,burglar ,,alarm ,,switch ,,or ,,circuit ,,breaker4 ,alarm1 ,electric4 ,an appliance for calling attention1 generally by ringing a bell4 ,it is used to notify of water-level in boilers or tanks1 of entrance of a house1 or of other things as desired4 ,it is evident that any number of alarms could be contrived4 #ah ,,standard ,,electrical ,,dictionary4 ,alarm1 ,fire and ,heat4 ,an alarm for giving notice of the existence of a conflagration4 ,such are sometimes operated by a compound bar thermostat 7see ,thermostat71 which on a given elevation of temperature closes a circuit and rings an electric bell4 ,sometimes the expansion of a column of mercury when heated is used4 ,this1 by coming in contact with one or two platinum points1 completes a circuit1 and rings the bell4 ,the identical apparatus may be used in living rooms1 greenhouses4 factories and elsewhere1 to give an alarm when the temperature rises or falls beyond predetermined limits4 ,alarm1 ,overflow4 ,an alarm to indicate an overflow of water has been suggested on the lines of a contact completed by water1 or of the elements of a battery which would be made active by water4 ,thus two sheets of metal might be separated by bibulous paper charged with salt4 ,if these sheets were terminals of a circuit including a bell and battery1 when water reached them the circuit would be closed and the bell would ring4 ,it was also proposed to use one copper and one zinc sheet so as to constitute a battery in itself1 to be thrown into action by moisture4 ,these contacts or inactive batteries could be distributed where water from an overflow would be most likely to reach them4 ,alarm1 ,water ,level4 ,an alarm operated by a change of water level in a tank or boiler4 ,by a float a contact is made as it rises with the water4 ,another float may be arranged to fall and close a contact as the level falls4 ,the closing of the contacts rings an electric bell to notify the attendant in charge4 ,alcohol1 ,electrical ,rectification of4 ,a current of electricity passed through impure alcohol between zinc electrodes is found to improve its quality4 ,this it does by decomposing the water present4 ,the nascent hydrogen combines with the aldehydes1 converting them into alcohols while the oxygen combines with the zinc electrode4 ,alignment4 ,the placing in or occupying of the same straight line4 ,the bearings of a shaft in dynamos1 engines1 and other machinery have to be in accurate alignment4 ,allotropy4 ,the power of existing in several modifications possessed by some substances1 notably by chemical elements4 ,instances of the allotropic state are found in carbon which exists as charcoal1 as graphite 7plumbago or black lead71 and as the diamond4 ,all three are the same elemental substance1 although differing in every physical and electrical property4 #ai ,,standard ,,electrical ,,dictionary4 ,alloy4 ,a mixture1 produced almost universally by fusion1 of two or more metals4 ,sometimes alloys seem to be chemical compounds1 as shown by their having generally a melting point lower than the average of those of their constituents4 ,an alloy of a metal with mercury is termed an amalgam4 ,an important application in electricity is the use of fusible alloys for fire alarms or for safety fuses4 ,german silver is also of importance for resistance coils1 and palladium alloys are used for unmagnetizable watches4 ,an alloy of wrought iron with manganese is almost unmagnetizable1 and has been proposed for use in ship building to avoid errors of the compass4 ,alloys or what are practically such can be deposited by electrolysis in the electro- plater's bath4 ,we give the composition of some alloys interesting to the electrician4 ,solder3 ,lead #a part ,tin #b parts #a #b ,german ,silver3 ,copper1 #b parts2 ,nickel1 #a part2 ,zinc1 #a part 7used for resistances74 ,platinum1 ,silver ,alloys3 ,platinum1 #a part2 silver1 #b parts 7used for resistances47 ,palladium alloys for watch springs4 7,see ,palladium47 ,alphabet1 ,telegraphic4 ,the combinations of sounds1 of dots and dashes marked on paper1 of right-hand and left-hand deflections of a needle1 of bells of different notes1 or of other symbols by which a fixed combination is expressed for each character of the alphabet1 for numerals1 and for punctuation4 ,while the code is designed for telegraphic uses it can be used not only for the conveyance of signals and messages by the electrical telegraphs1 but also by any semaphoric or visual system1 as by flashes of light1 movements of a flag or even of the arms of the person signalling4 ,in the ,english and continental needle telegraphy in which the message is transmitted by the movements of an index normally vertical1 but oscillating to one side or the other under the influence of the current1 the latter being controlled by the transmitter of the message1 the left hand swings of the needle are interpreted as dots1 the right hand as dashes4 ,this system enables one alphabet to be translated into the other1 or virtually one alphabet answers for both ,morse and needle transmitters4 ,there are two principal telegraphic alphabets1 the ,american ,morse and the ,international codes4 ,they are very similar1 their essential distinction being that spaces are used in the ,american code1 while they are excluded from the ,international code4 ,in the ,american ,morse system the message is now universally received by sound4 7,see ,sounder--,sound ,reading47 #bj ,,standard ,,electrical ,,dictionary4 ,the two codes or telegraphic alphabets are given here4 ,,the ,,international ,,alphabet4 ,parenthesis1 - 4 - - 4 - ,understand1 444 - 4 ,i don't understand1 44-- 4444--44 ,wait1 4-4 4 4 ,erase1 444 444 444 ,call signal1 -4-4-4- ,end of message1 4-4-4-4 ,cleared out all right1 4-44-44-4 ,a 4- ,l 4-44 ,w 4-- ,b -444 ,m -- ,x -44- ,c -4-4 ,n -4 ,y -4-- ,d -44 ,o --- ,z --44 ,e 4 ,p 4--4 ,f 44-4 ,q --4- ,ch ---- ,g --4 ,r 4-4 4-4- ,h 4444 ,s 444 ---4 ,i 44 ,t - 44-- ,j 4--- ,u 44- 44-44 ,k -4- ,v 444- --4-- ,,numerals #a 4---- #d 4444- #h ---44 #b 44--- #e 44444 #i ----4 #c 444-- #f -4444 #j ----- #g --444 ,transcriber's note3 ,the original image of the dot_/dash pattern is somewhat ambiguous4 ,since there may be differences from contemporary specifications1 the original image is included4 ,image of page #bj3 ,,the ,,international ,,alphabet4 #ba ,,standard ,,electrical ,,dictionary4 ,,punctuation1 ,,etc41 ,period 747 444 444 ,comma 717 4-4-4- ,query787 44--44 ,exclamation 767 --44-- ,apostrophe 7'7 4----4 ,hyphen 7-7 -4444- ,fresh paragraph1 4-4-44 ,inverted commas1 -44-4 ,,the ,,american ,,alphabet4 ,a 4- ,l ----7,continuous7 ,w 4-- ,b -444 ,m -- ,x 4-44 ,c 44s4 ,n -4 ,y 44s44 ,d -44 ,o 4s4 ,z '''4 ,e 4 ,p 44444 ,f 4-4 ,q 44-4 ,ch ---- ,g --4 ,r 4s44 4-4- ,h 4444 ,s 444 ---4 ,i 44 ,t - 44-- ,j - 4 - 4 ,u 44- 44-44 ,k -4- ,v 444- --4-- ,,numerals #a 4--4 #d 4444- #h -4444 #b 44-44 #e --- #i -44- #c 444-4 #f 444 444 #j -----7,continuous7 #g --44 ,transcriber's ,note3 ,the s in the ,american ,code indicates a space4 ,i leave the following to the reader's imagination4 ,see the original image4 ,comma 717 ,semicolon 727 ,colon 737 ,colon ,dash 737 ,period 747 ,interrogation 787 ,exclamation 767 ,dash 7-7 ,hyphen 7-7 ,pound ,sterling 77 ,shilling ,mark 7 7 ,image of page #ba3 ,,the ,,american ,,alphabet4 #bb ,,standard ,,electrical ,,dictionary4 ,transcriber's ,note3 ,i leave these to the reader's imagination4 ,see the following original image4 ,dollars 77 ,decimal ,point 747 ,cents 7c7 ,paragraph 77 ,pence 7d47 ,fractional ,mark 7--7 ,capitalized ,letter ,italics or ,underline ,colon followed by ,quotation 3 ,parenthesis 7 7 ,brackets ,quotation ,marks ,quotation within a ,quotation ' ' ,image of page #bb3 ,,the ,,american ,,alphabet4 ,the principal differences in the two codes are the use of spaces in the ,american code1 such being excluded from the ,international code4 ,this affects the letters ,c1 ,r1 ,y1 ,z4 ,the following diagram1 due to ,commandant ,perian1 enables the letter corresponding to an ,international code sign to be rapidly found with the exception of ,r4 - dot start dash - _/ ,e ,t _/ _/ ,i ,a ,n ,m _/ _/ _/ _/ ,s ,u ,r ,w ,d ,k ,g ,o _/ _/ _/ _/ _/ _/ _/ _/ ,h ,v ,f ,u ,l ,a ,p ,j ,b ,x ,c ,y ,z ,q ,,ch ,fig4 #aj4 ,diagram for translating the ,morse ,alphabet4 ,in order to find what letter corresponds to a given sign1 starting from the top of the diagram1 each line is traced down to a bifurcation1 taking the right hand line of each bifurcation for a dash1 and the left hand line for a dot1 and stopping when the dots and dashes are used up4 ,thus1 for example1 the signal -4- - leads us to the letter d1 the signal - - - - to the letter j and so on4 #bc ,,standard ,,electrical ,,dictionary4 ,alternating4 adj4 ,term descriptive of a current changing periodically in direction4 7,see ,current1 ,alternating47 ,synonyms--,oscillatory--periodic--undul atory--harmonic4 ,alternating ,current ,arc4 ,the arc produced by the alternating current4 ,it presents several peculiarities4 ,with an insufficient number of alternations per second it goes out4 ,as the carbons wear away equally it is adopted for such lamps as the ,jablochkoff candle1 7see ,candle1 ,jablochkoff74 ,as no crater is formed the light is disseminated equally both up and down4 ,for this reason to get full downward illumination a reflector is recommended4 ,alternating ,current ,system4 ,a system of electric distribution employing the alternating current4 ,for transmission in the open air or in conduits a high potential circuit is used1 from #a1jjj to #aj1jjj volts being maintained at the central station4 ,two leads unconnected at the end lead from the station4 ,where current is desired a converter or transformer 7see ,converter7 is placed1 whose primary is connected to the two leads bridging the interval between them4 ,from the secondary the house leads are taken with an initial potential in some cases of #ej volts4 ,the converters are thus all placed in parallel4 ,by law or insurance rules the converters are generally kept outside of buildings4 ,where no secondary current is taken from the converters very little primary current passes them on account of their counter-electromotive force4 ,as more secondary current is taken the primary increases and this accommodation of one to the other is one of the interesting and valuable features4 ,street lamps are sometimes connected in series4 ,each lamp in such case is in parallel with a small coil with iron core4 ,while the lamp is intact little current passes through the coil4 ,if the lamp is broken1 then the converter impedes the current by its spurious resistance1 q4 v41 just enough to represent and replace the resistance of the extinguished and broken lamp filament4 7,see ,meter1 ,alternating ,current2 ,motor1 ,alternating ,current47 ,alternation4 ,the change in direction of a current4 ,the number of such changes is expressed as number of alternations2 thus a current may have a frequency of #ejj or #bj1jjj alternations per second4 ,transcriber's note3 ,one alternation per second is now called one hertz4 ,alternation1 ,complete4 ,a double alternation2 a change from one direction to the other and back again to the original phase4 ,a symbol derived from its graphic representation by a sine curve is used to indicate it4 ,the symbol is #bd ,,standard ,,electrical ,,dictionary4 ,alternative ,path4 ,a second path for a current appearing as a disruptive discharge4 ,where two paths are offered the discharge1 as it is of alternating or oscillatory type1 selects the path of least self-induction4 ,thus a thick bar of copper1 with no air gap1 may be abandoned by the current in favor of a small iron wire with an air gap1 but which has less self-induction4 ,the lightning arresters1 q4 v41 for the protection of telegraph offices are sometimes based on these principles4 ,a path of very high resistance but of small self-induction is offered between the line and the earth4 ,this the lightning discharge selects in preference to the instruments with their iron cores1 as the latter are of very high self-induction4 ,alternator4 ,a dynamo electric generator supplying an alternating current4 7,see ,dynamo1 ,alternating ,current47 ,synonym--,alternating current generator or dynamo4 ,alternator1 ,constant ,current4 ,an alternating current dynamo supplying a current of unvarying virtual amperage4 ,alternators of this type are constructed with an armature of high self-induction4 ,sometimes fine winding contained in deep peripheral notches in the core-discs is employed to magnify the self-induction4 ,such generators are employed for series lighting1 especially arc-lighting4 ,aluminum4 ,a metal2 one of the elements2 symbol3 ,al4 ,atomic weight3 #bg4d4 ,equivalent3 #i4ac4 ,valency3 #c4 ,specific gravity3 #b4f4 ,it is a conductor of electricity4 ,relative resistance annealed1 7,silver #a7 #a4ice ,specific resistance at #j;,c 7#cb;,f47 #b4iab microhms ,resistance of a wire at #j;,c 7#cb;,f47 a7 #a foot long1 weighing #a grain1 #j4ajgd ohms4 b7 #a foot long1 #a_/ajjj inch thick1 #ag4ec c7 #a meter long1 weighing #a gram1 #j4jgdi d7 #a meter long1 #a millimeter thick #j4jcgaj ,resistance of a #a-;inch cube at #j;,c 7#cb;,f47 #a4adg microhms ,electro-chemical equivalent4 4#jieh 7hydrogen 4#jaje7 #be ,,standard ,,electrical ,,dictionary4 ,amalgam4 7a7 ,a combination or alloy in which one of the constituents is mercury4 ,usually the term is applied to an alloy of a single metal with mercury4 ,some metals readily form amalgams2 such metals are3 ,gold1 zinc1 silver1 lead and others2 some1 such as platinum and iron1 form amalgams only under exceptional circumstances4 7b7 ,the word is also applied to compositions for application to the cushions of frictional electric machine in which cases it is often a misnomer4 ,true amalgams used for this purpose are made as follows3 7a7 ,tin1 #a part2 ,zinc1 #a part2 ,mercury1 #b parts 7,kienmayer74 7b7 ,tin1 #b parts2 ,zinc1 #c parts4 7c7 ,tin1 #c parts2 ,zinc1 #e parts2 ,mercury1 #d parts4 7d7 ,zinc1 #a part3 ,mercury1 #d parts2 ,mercury1 #i parts4 sic ,the tin1 if such is used1 7formula a1 b and c7 is first melted1 the zinc is added in successive portions4 ,the mercury1 which must be heated1 is slowly poured into the melted alloy after removal of the latter from the fire1 and the mixture1 while making1 is constantly stirred4 ,it is kept stirred or rubbed in a mortar until cold4 ,sometimes it is poured into water and kept in constant agitation until cold4 ,it is thus obtained in a granular condition1 and is pounded in a mortar until reduced to powder4 ,it must be dried and kept in tightly stopped bottles and is applied to the cushions after they have been greased4 ,it is to be noticed that it is said that alloy 7d7 requires no pulverization beyond constant rubbing in a mortar as it cools4 ,sometimes the amalgam is shaken about in a wooden tray with chalk while cooling4 ,the action of amalgams is not very clearly understood4 ,some claim that there is a chemical action1 others that they simply act as conductors1 others that they are more highly negative to the glass than the leather of the cushions4 ,graphite or sulphide of tin 7mosaic gold7 are sometimes used to coat the cushions2 it is these that are sometimes incorrectly called amalgams4 ,amalgamation4 ,the application of mercury to a metal with which it forms an amalgam1 or with which it amalgamates4 ,battery zincs are amalgamated in two ways4 ,in the immersion method1 the plate is dipped into an acid solution of mercuric chloride or nitrate4 ,the latter is best4 ,in the direct application method the plate is first wet all over with dilute acid and a little mercury is dropped upon it and is rubbed over the surface with a rag or1 what is better1 with a piece of galvanized iron4 ,a very little mercury answers the purpose4 ,the whole surface of the plate should be left as bright as silver4 7,see ,action1 ,local47 ,amber4 ,amber is a fossil resin1 supposed to be a product of the extinct ,pinites ,succinifer and other coniferous trees4 ,most of it is gathered on the shores of the ,baltic between ,koenigsberg and ,memel4 ,it is also found in small pieces at ,gay ,head1 ,mass41 and in ,new ,jersey green sand4 ,it is found among the prehistoric remains of the ,swiss ,lake dwellers4 ,when rubbed with a cloth it becomes excited with negative electricity4 ,the ,greek word for it is electron1 which gave the name electricity to the modern science4 ,thales of ,miletus1 #fjj ,b4 ,c41 and ,theophrastus1 about #cjj ,b4 ,c41 both mention its electric properties or power of attracting small objects when rubbed4 #bf ,,standard ,,electrical ,,dictionary4 ,ammeter4 ,the commercial name for an ampere-meter1 an instrument designed to show by direct reading the number of amperes of current which are passing through a circuit4 ,a great variety of ammeters have been invented1 based on different principles4 ,the definitions following this one give some idea of the lines of construction followed4 ,synonym--,ampere meter4 ,ammeter1 ,ayrton's4 ,a direct reading instrument for measuring current intensity4 ,a solenoid receives the current4 ,in the axis of the solenoid an iron tube is suspended by a long spiral spring that passes down within it1 and the upper end of which spring is fastened to the glass top of the instrument4 ,the tube is provided with proper guides so as to maintain a vertical position1 and is free to rotate4 ,its upper end carries an index4 ,the whole operates as a magnifying device4 ,a slight longitudinal displacement of the tube causes it to rotate through a considerable angle by the action of the spring4 ,by properly proportioning the parts1 the angle of displacement of the index is directly proportional to the current between #ae and #bgj angular displacement4 ,the same instrument is wound for use as a volt-meter4 ,its principal fault is its restricted range4 ,ammeter1 ,commutator4 ,a commutator ammeter is one whose windings consist of separate strands1 each of any desired number of turns1 and provided with a commutating attachment for throwing them into series or into parallel as desired4 ,the essential condition is that all the wires shall be of equal resistance and of equal number of turns4 ,such an instrument can be used for heavy or light currents4 ,two sets of graduations are marked on its scale if it is a calibrated instrument4 7,see ,calibration47 ,commutator volt-meters are constructed on the same principle4 ,ammeter1 ,cunynghame's4 ,a modification of the ,siemens' electro-dynamometer4 7,see ,electro-dynamometer1 ,siemens'47 ,an electro-magnet with very massive core is excited by the current4 ,as the core is of small reluctance the strength of the magnet is nearly proportional to the current strength4 ,between the poles of the magnet a soft iron armature or induced magnet is pivoted4 ,it carries a pointer so adjusted that when the axis of the soft iron magnet is at an angle of about #cj with the line joining the poles of the electro-magnet the pointer will indicate zero4 ,the soft iron armature is so massive that the magnetism induced in it is proportional to the strength of the electro-magnet4 ,hence the couple exerted by the electro-magnet on the pivoted armature will be proportional to the square of the current4 ,the armature is retained in place by a spiral spring lying in line with its axis of rotation4 ,the instrument is operated as a zero reading instrument4 ,the current is passed through it4 ,the needle is deflected2 it is brought back to zero by turning a milled head which twists the spring4 ,the current will be proportional to the square root of the angle of displacement of the milled head4 ,a scale with index is provided1 giving directly the square roots of the angle over which the pointer is moved4 ,the same instrument is wound for use as a volt-meter4 #bg ,,standard ,,electrical ,,dictionary4 ,ammeter1 ,eccentric ,iron ,disc4 ,this ammeter comprises a cylindrical electro-magnet excited by the current to be measured4 ,a disc of iron free to rotate is suspended on pivots below it4 ,a piece is cut off the disc at one part of its periphery so as to give more metal to one side than to the other4 ,in its zero position this portion of the disc swings towards the magnet4 ,as the latter is more and more excited the other or more projecting portion of the disc turns towards it1 being attracted like an armature1 and moves against the force of gravity1 the disc rotating4 ,an index attached to the disc swings over the face of a graduated scale4 ,the disc is so counterpoised that in its natural position the index points to zero4 ,ammeter1 ,electro-magnetic4 ,an ammeter depending for its working upon the action of an electro-magnet1 which is excited by the current to be measured4 ,ammeter1 ,gravity4 ,an ammeter whose hand or index is drawn into the zero position by gravity1 and whose displacement therefrom is produced by the action of the current to be measured4 ,fig4 #aa4 ,,gravity ,,solenoid ,,ammeter4 ,ammeter1 ,magnetic ,vane4 ,a fixed plate of soft iron is placed within a coil4 ,facing it is a second disc free to move or swing on an axis4 ,when the field is excited the two repel each other because like polarity is induced in each1 and the motion of the movable disc indicates the strength of the current4 ,the same instrument is wound for high resistance and constitutes a ,magnetic ,vane ,voltmeter4 #bh ,,standard ,,electrical ,,dictionary4 ,ammeter1 ,magnifying ,spring4 ,a solenoid ammeter in which a spiral spring is used to convert the longitudinal motion of the armature or movable core into a rotary motion 7see ,ammeter1 ,ayrton's7 and magnify the apparent range of motion4 ,ammeter1 ,permanent ,magnet4 ,an ammeter with a magnetic field produced by a permanent magnet4 ,ammeter1 ,solenoid4 ,an ammeter in which the attraction1 when a current is passing through it1 exerted by a hollow coil of wire upon an iron bar or tube in line with its axis1 is utilized to indicate the strength of current4 ,the bar is drawn into the coil to different extents proportional to the attraction4 ,as an example see ,ammeter1 ,ayrton's1 and cut of ,gravity ,ammeter4 ,ammeter1 ,spring4 ,an ammeter in which the part moved by the current is controlled or brought to the zero position by a spring4 ,ammeter1 ,steel ,yard4 ,a solenoid ammeter in which the solenoid core is suspended vertically from the short end of a steel yard fitted with a sliding weight4 ,the current passes through the solenoid coil and attracts or draws downwards the coil4 ,a sliding weight is moved in and out on the long steel-yard arm which is graduated for amperes4 ,in use the weight is slid out until the arm is in equipose2 the divisions give the amperes4 ,fig4 #ab4 ,,steel ,,yard ,,ammeter4 #bi ,,standard ,,electrical ,,dictionary4 ,ammunition ,hoist1 ,electric4 ,an apparatus for use on ships for hoisting ammunition to the guns by an electric elevator4 ,the characteristic feature of it is that a constant motion of the switch or handle is required to keep it in action4 ,if the operator is shot so as to be incapacitated from taking charge of the switch1 the hoist stops until another is assigned to it4 ,amperage4 ,current intensity expressed in amperes1 as an amperage of ten amperes4 ,ampere4 ,the practical unit of electric current strength4 ,it is the measure of the current produced by an electro-motive force of one volt through a resistance of one ohm4 ,in electric quantity it is the rate of one coulomb per second4 ,it is one-tenth the absolute ,c4 ,g4 ,s4 unit of current strength4 ,its best analogy is derived from water4 ,assuming the electric current to be represented by a current of water1 the pressure1 head1 or descent producing such current would be the electro-motive force4 ,the current might be measured in gallons 7or other unit7 passed per second4 ,in the analogy these gallons would be coulombs4 ,but it might be measured by reference to a standard stream1 as for instance1 the stream which would pass through a hole an inch square under a given head1 say six inches of water4 ,this unit is the miner's inch1 and is the exact analogy of the ampere4 ,a current of water may flow at the rate of so many miner's inches1 just as a current of electricity may flow at the rate of so many amperes4 ,in neither case it will be noted is there any reference to time4 ,an ampere per second is a redundant expression1 and means no more than an ampere2 an ampere-second1 on the other hand1 is a coulomb4 ,the number of coulombs passed per second gives the amperes of current4 ,for value of ampere1 see ,coulomb4 ,transcriber's note3 ,the ,,si definition of an ampere3 ,a current in two straight parallel conductors of infinite length and negligible cross-section1 #a metre apart in vacuum1 would produce a force equal to #b;,e-#g newton per metre of length4 ,fig4 #ac4 ,,the ,,miner',s ,,inch ,,as ,,an ,,analogy ,,for ,,the ,,ampere4 #cj ,,standard ,,electrical ,,dictionary4 ,ampere1 ,arc4 ,a conductor bent into the arc of a circle1 and employed in measuring the electric current by the electric balance4 ,ampere-currents4 ,the currents assumed to be the cause of magnetism4 7,see ,magnetism1 ,ampere's ,theory of47 ,ampere-feet4 ,the product of amperes of current by the length1 in feet1 of a conductor passing such current4 ,it may be in empiric calculations of dynamo or motor construction1 but is little used4 ,one ampere-foot is a current of one ampere passing through one foot length of a conductor1 or one-tenth ampere through ten feet1 and so on4 ,ampere-hour4 ,the quantity of electricity passed by a current of one ampere in one hour4 ,it is used by electric power and lighting companies as the unit of energy supplied by them1 because they maintain a constant potential difference in their leads1 so that only the amperes and hours need measuring or recording to give the energy1 viz4 3 volt-ampere-hours4 ,the same unit is applied to batteries to indicate their potential energy1 because they also are assumed to be of constant voltage or electro-motive force4 ,ampere-meters4 ,the product of amperes of current by the length1 in meters1 of a conductor carrying such current4 ,one ampere-meter is a current of one ampere passing through one meter of a conductor4 ,the term must not be confused with the identically spelled ,ampere-meter1 a synonym for ,ammeter4 ,ampere-minute4 ,the quantity of electricity passed by a current of one ampere in one minute2 sixty coulombs4 ,ampere ,ring4 ,a conductor forming a ring or circle used in electric balances for measuring currents4 7,see ,balance1 ,ampere47 ,ampere-second4 ,the quantity of electricity passed by a current of one ampere in one second2 the coulomb1 q4 v4 ,amperes1 ,lost4 ,in a shunt or compound-wound dynamo1 part of the total amperes of current produced in the armature coils go through the shunt1 and hence1 do not appear in the outer circuit4 ,s4 ,p4 ,thompson has proposed the term lost amperes for this portion of the current4 ,ampere's ,memoria ,technica4 ,an expression of the effect of a current on a magnetic needle4 ,if we imagine the observer in the line of the current and facing the magnetic needle1 the current entering by his feet and leaving by his head1 the north pole is deflected to his left4 #ca ,,standard ,,electrical ,,dictionary4 ,ampere-turns4 ,the amperes of current supplied to a magnet coil multiplied by the number of turns the current makes in the coil4 ,if the coil is wound two or three in parallel1 the virtual turns by which the amperes are multiplied are one-half or one-third the actual turns of wire4 ,synonym--,ampere ,windings4 ,ampere-turns1 ,primary4 ,the ampere-turns in the primary coil of an induction coil or transformer4 ,ampere-turns1 ,secondary4 ,the ampere-turns in the secondary coil of an induction coil or transformer4 ,amplitude of ,waves4 ,waves are distinguished by length and amplitude4 ,the latter1 in the case of transverse waves1 such as those of water and of the ether1 correspond with and measure the height from lowest to highest point1 or from valley to summit of the waves in question4 ,in the case of longitudinal waves1 such as those of the air1 due to sounding bodies1 the ratio of degree of rarefaction to degree of condensation existing in the system is the amplitude4 ,the latter can be graphically represented by a sinuous line1 such as would represent the section of a transverse wave4 ,ether waves are produced by heated bodies and by electro-magnetic impulses1 as in the discharge of the ,leyden jar4 ,the amplitude of a wave1 other things being equal1 is the measure of its intensity4 ,thus1 the louder a sound the greater is the amplitude of the system of waves to which it is due4 ,the same applies to ether waves1 whether they are perceived in the electro-magnetic1 light1 or heat-giving modification4 ,as the amplitude of ether waves cannot be accurately known1 amplitude is a relative term and is not stated generally in any absolute unit4 ,analogous ,pole4 ,one of the elements of a pyro-electric crystalline substance1 such as tourmaline4 ,when heated1 such bodies acquire electrical properties4 ,if of such crystalline form that they are differently modified at the ends of their crystalline axis1 by hemihedral modifications1 the ends may be differently affected4 ,one end may show positive electricity when the temperature is rising1 and negative when falling4 ,such end is then called the analogous pole4 ,the opposite end presents1 in such cases1 the opposite phenomena2 becoming negative when the temperature is rising1 and becoming positive when it is falling2 such end is called the antilogous pole4 ,analysis4 ,the determination of the elements of a case4 ,it may be chemical1 and consist in finding what a substance consists of2 it may be mathematical1 and consist in determining the unknown quantities in a problem2 or it may belong to other branches of science4 ,the term has a very extended application4 ,where the constituents are only determined in kind it is called qualitative analysis2 where their quantity or percentage is ascertained it is called quantitative analysis4 #cb ,,standard ,,electrical ,,dictionary4 ,analysis1 ,electric4 ,chemical analysis by electrolytic methods4 7,see ,electrolytic ,analysis47 ,analyzer1 ,electric4 ,an apparatus used in investigations on electric ether waves4 ,it consists of a series of parallel metallic wires4 ,when the electric waves have been polarized1 the analyzer will only permit them to go through it intact1 when the plane of vibration of the waves is parallel to its wires4 ,anelectrics4 7a7 ,bodies which do not become electrified by friction2 a term introduced by ,gilbert1 now little used1 as all bodies develop electricity under proper conditions by contact action2 the reverse of idioelectrtics4 7b7 ,also a conductor of electricity1 the reverse of a dielectric1 q4 v4 7,see ,conductor47 ,it will be seen that ,gilbert's anelectrics were1 after all1 the same as the modern anelectrics1 i4e41 conductors4 ,anelectrotonus4 ,a term used in medical electricity or electro-therapeutics to indicate the deceased functional activity induced in a nerve by the proximity of the anode of an active electric circuit completed through the nerve4 ,the converse of ,kathelectrotonus4 ,angle of ,declination4 ,the angle of error of the magnetic needle or compass1 measuring the extent of its deviation from the meridian in any locality4 ,it is the angle between the plane of the magnetic axis of a magnetic needle free to take its natural position1 and the geographical meridian1 the needle being counterpoised if necessary1 so as to hold an absolutely horizontal position4 ,the deviation is expressed as being east or west1 referring always to the north pole4 7,see ,magnetic ,elements47 ,synonym--,variation of the ,compass4 ,transcriber's note3 ,see ,agonic ,line4 ,angle of the ,polar ,span4 ,in a dynamo or motor the angle subtended by the portion of a pole piece facing the armature1 such angle being referred to the centre of the cross-section of the armature as its centre4 ,,standard ,,electrical ,,dictionary4 #cc ,angular ,velocity4 ,the velocity of a body moving in a circular path1 measured with reference to the angle it passes over in one second multiplied by the radius and divided by the time4 ,a unit angle is taken 7#eg4biegh #eg #ag' #dd4h nearly7 such that it is subtended by a portion of the circumference equal in length to the radius4 ,hence1 the circumference1 which is #cfj1 is equal to #b99,,pi99unit angle1 ,,pi being equal to #c4adaf--4 ,unit angular velocity is such as would in a circle of radius #a represent a path #a1 traversed in unit time #a second4 ,if the radius is r and the angle passed over is theta1 the distance is proportional to r99theta2 if this distance is traversed in t seconds the angular velocity is theta _/ t4 ,the angular velocity1 if it is multiplied by r1 theta expressing a distance1 will give the linear velocity4 ,the dimensions of angular velocity are an angle 7 arc _/ radius7 _/ a ,time 7,l_/,l7_/,t 7,t-#a74 ,the velocity expressed by the rate of an arc of a circle of unit radius1 which arc subtends an angle of #eg #ag' #dd4h1 such arc being traversed in unit time1 is unit angular velocity4 ,animal ,electricity4 ,electricity1 notably of high tension1 generated in the animal system1 in the ,torpedo1 ,gymnotus and ,silurus4 ,the shocks given by these fish are sometimes very severe4 ,the gymnotus1 or electric eel1 was elaborately investigated by ,faraday4 ,it has the power of voluntarily effecting this discharge4 ,there is undoubtedly some electricity in all animals4 ,the contact of the spinal column of a recently killed frog with the lumbar muscles produces contraction1 showing electric excitement4 ,currents can be obtained from nerve and muscle1 or from muscle sides and muscle cut transversely1 in each case one thing representing positive and the other negative elements of a couple4 ,angle of ,inclination or ,dip4 ,the angle which the magnetic axis of a magnet1 which magnet is free to move in the vertical plane of the magnetic meridian1 makes with a horizontal line intersecting such axis4 ,to observe it a special instrument1 the dipping compass1 inclination compass1 dipping needle1 or dipping circle1 as it is called1 is used4 7,see ,elements1 ,magnetic1 --,dipping ,needle1--,compass1 ,inclination47 ,angle of ,lag4 ,the angle expressing the displacement of the magnetic axis of the armature core of a dynamo in the direction of its rotation4 7,see ,lag47 ,lag is due to the motion of the armature core4 ,angle of ,lead4 ,the angle expressing the displacement in the direction of rotation of the armature of a dynamo which has to be given the brushes to compensate for the lag4 7,see ,lag47 ,this is positive lead4 ,in a motor the brushes are set the other way1 giving a negative angle of lead or angle of negative lead4 ,anion4 ,the electro-negative element or radical of a molecule1 such as oxygen1 chlorine or the radical sulphion4 7,see ,ions47 ,it is the portion which goes to the anode1 q4v41 in electrolytic decomposition4 #cd ,,standard ,,electrical ,,dictionary4 ,anisotropic4 7adj47 ,unequal in physical properties1 as in conduction and specific inductive capacity1 along various axes or directions4 ,an anisotropic conductor is one whose conductivity varies according to the direction of the current1 each axis of crystallization in a crystalline body marking a direction of different conductivity4 ,an anisotropic medium is one varying in like manner with regard to its specific inductive capacity4 ,in magnetism an anisotropic substance is one having different susceptibilities to magnetism in different directions4 ,the term is applicable to other than electric or magnetic subjects4 ,synonym--,a,eolotropic4 ,annealing1 ,electric4 ,annealing by the heat produced by the passage of the electric current through the body to be annealed4 ,the object is clamped or otherwise brought into a circuit1 and a current strong enough to heat it to redness1 or to the desired temperature is passed through it4 ,annunciator4 ,an apparatus for announcing a call from any place to another1 as from a living-room to an office in a hotel1 or for announcing the entering of any given room or window in a building protected by a burglar alarm4 ,a usual system comprises for each annunciator an electro-magnet4 ,its armature is normally held away from its poles by a spring1 and when in that position a latch connected to the armature holds a little shutter4 ,when by a push-button or other device a current is sent through a circuit which includes the electro-magnet the armature is attracted1 this releases the latch and the shutter drops4 ,in dropping it displays a number1 letter or inscription which indicates the locality of the push-button or other circuit-closing device4 ,often annunciators are connected in circuit with a bell4 ,fig4 #ad4 ,,annunciator4 #ce ,,standard ,,electrical ,,dictionary4 ,annunciator ,clock4 ,a clock operating an annunciator by making contact at determined times4 ,annunciator ,drop4 ,the little shutter which is dropped by some forms of annunciators1 and whose fall discloses a number1 character or inscription1 indicating whence the call was sent4 ,fig4 #ae4 ,,drop ,,annunciator4 ,fig4 #af4 ,,annunciator ,,detaching ,,mechanism4 ,annunciator1 ,gravity ,drop4 ,an annunciator whose operations release shutters which fall by gravity4 ,annunciator1 ,needle4 ,a needle annunciator is one whose indications are given by the movements of needles1 of which there is usually a separate one for each place of calling4 ,annunciator1 ,swinging or ,pendulum4 ,an annunciator which gives its indications by displacing from its vertical position a pendulum or vertically suspended arm4 #cf ,,standard ,,electrical ,,dictionary4 ,anodal ,diffusion4 ,a term in electro-therapeutics2 the introduction of a medicine into the animal system by using a sponge-anode saturated with the solution of the drug in question4 ,on passing a current the desired result is secured by cataphoresis1 q4 v4 ,anode4 ,the positive terminal in a broken metallic or true conducting circuit2 the terminal connected to the carbon plate of a galvanic battery or to its equivalent in case of any other generator4 ,in general practice it is restricted to the positive terminal in a decomposition or electrolytic cell1 such as the nickel anode in a nickel-plating bath or the anode of platinum in a gas voltameter4 ,it is the terminal out of or from which the current is supposed to flow through the decomposition cell4 ,in electro-therapeutics the term is used simply to indicate the positive terminal4 ,in an electrolytic cell the electro-negative substance or anion goes to the anode4 ,hence1 it is the one dissolved1 if either are attacked4 ,the nickel1 copper or silver anodes of the electroplater dissolve in use and keep up the strength of the bath4 ,the platinum anode in a gas voltameter is unattacked because the anion cannot act upon it chemically4 ,anodic ,closure ,contraction4 ,a physiological change in a living subject produced by the closing of the electric current2 the muscular contraction which takes place beneath the anode applied to the surface of the body when the circuit is closed1 the kathode being applied elsewhere2 it is due1 presumably1 to direct action on the motor nerve4 ,it is a term in electro-therapeutics4 ,it is the converse of anodic opening contraction1 q4 v4 ,an abbreviation ,a4 ,c4 ,c4 is often used to designate it4 ,anodic ,duration ,contraction4 ,a term in electro-therapeutics4 ,on the opening or closing of an electric circuit1 the anode of which is placed over a muscle1 a contraction is observed 7see ,anodic ,closure ,contraction--,anodic ,opening ,contraction74 ,the above term is used to designate the duration of such contraction4 ,an abbreviation ,a4 ,d4 ,c4 is often used to designate it4 ,anodic ,opening ,contraction4 ,the converse of ,anodic ,closure ,contraction1 q4 v42 it is the contraction of living muscle beneath or near the anode where the circuit1 including such anode and the body in its course1 is closed2 a physiological phenomenon observed in electro-therapeutics to which branch of science the term belongs4 ,an abbreviation ,a4 ,o4 ,c4 is often used to designate it4 ,anodic ,reactions4 ,a term in electro-therapeutics2 the diagnosis of disease by the actions of the tissue near the anode of a circuit4 ,anti-,induction ,conductor4 ,a conductor constructed to avoid induction effects in the conducting element4 ,many kinds have been made4 ,a tubular metal shield or envelope which may be grounded will protect an enclosed conductor to some extent4 ,or the conductor may be a double wire twisted around itself1 one branch being used for the regular and the other for the return circuit1 thus constituting a closed metallic circuit4 ,the inductive effects are due to interrupted or varying currents in neighboring wires and circuits4 ,many anti-induction conductors have been invented and patented4 #cg ,,standard ,,electrical ,,dictionary4 ,anti-magnetic ,shield4 ,in general terms a hollow screen of soft iron designed to protect any mass of steel behind or enclosed by it from magnetization by any magnet near it1 such as a dynamo field magnet4 ,this it does by concentrating the lines of force within its own mass1 so that the space within it or enclosed by it is comparatively free from lines of force4 ,it is often applied to watches1 and is virtually an iron case in which they are enclosed4 ,antimony4 ,a metal1 one of the elements1 atomic weight1 #abb3 equivalent1 #dj4f and #bd4d2 valency1 #c and #e2 specific gravity1 #f4h4 ,it is a conductor of electricity4 ,relative resistance1 compressed 7silver #a71 #bc4fj ,specific resistance1 #ce4ej microhms4 ,resistance of a wire1 7a7 #a foot long1 weighing #a grain1 #c4dah ohms4 7b7 #a foot long1 #a_/ajjj inch thick1 #bac4f 7c7 #a meter long1 weighing #a gram1 #b4chd 7d7 #a meter long4 #a millimeter thick1 #j4deba ,resistance of a #a-;inch cube1 #ac4ih microhms4 ,approximate percentage resistance per degree ,c4 7#a4h ,f4 at #bj ,c4 #hh ,f47 #j4chi per cent4 ,elcctro-chemical equivalent 7hydrogen 4#jaje7 4#befj 7,see ,thermo-,electric ,series47 ,anvil4 ,an intermittent contact1 or make and break of the current is sometimes produced by directly pressing a key down upon a metallic surface1 the two being terminals of the circuit4 ,the surface or stud on which such pressure is produced is called the anvil4 ,the ordinary telegraph key1 which makes a contact by the pressure of the operator's fingers does it by making a contact between a contact piece upon the front end of the key and the anvil4 ,in the induction coil the anvil is also found4 ,thus in the cut representing the end of an induction coil and its circuit breaker in which ,o and ,o' and ,p and ,p' represent the secondary circuit terminal connections ,a is the core of soft iron wires1 h is the anvil2 the hammer when resting upon it so as to be in contact closes the circuit4 ,when the current coming from the primary to the post i1 passes through the hammer and anvil h1 and emerges by m1 it magnetizes the core2 this attracts the hammer1 which is made of or is armed with a mass of iron4 ,this breaks the circuit4 ,the hammer falls at once on the anvil1 again making the circuit1 and the action is repeated with great rapidity4 ,hammer and anvil or key and anvil connections should be made of platinum4 ,fig4 #ag4 ,,induction ,,coil ,,circuit ,,breaker4 #ch ,,standard ,,electrical ,,dictionary4 ,a4 ,o4 ,c4 ,abbreviation for ,anodic ,opening ,contraction1 q4 v4 ,aperiodic4 adj4 ,in an oscillating apparatus1 or in the oscillating member of apparatus1 the fact of having no reference to time of vibration2 dead-beat4 ,synonym4 ,dead-beat4 #ci ,,standard ,,electrical ,,dictionary4 ,fig4 #ah4 ,,arago',s ,,disc4 ,arago's ,disc4 ,an apparatus consisting of a disc of copper mounted horizontally1 or on a vertical spindle1 and so arranged as to be susceptible of rapid rotation4 ,immediately over it1 and best with a pane of glass intervening1 a magnetic needle is mounted on a pivot directly over the axis of the disc4 ,if the disc is rotated the lines of force of the magnet are cut by it1 and consequently currents are produced in the copper4 ,these currents act upon the needle and cause it to rotate1 although quite disconnected4 ,it is advisable for the needle to be strong and close to the disc1 which should rotate rapidly4 ,arc v4 ,to form a voltaic arc4 ,arc1 ,compound4 ,a voltaic arc springing across between more than two electrodes4 ,arc1 ,metallic4 ,the voltaic arc produced between terminals or electrodes of metal4 ,the characteristics of such arc as contrasted with the more usual arc between carbon electrodes are its greater length for the same expenditure of energy1 its flaming character and characteristic colors due to the metals employed4 ,it is sometimes1 for the latter reason1 used in spectroscopic investigations4 ,arc ,micrometer4 ,a micrometer for measuring the distance between the electrodes of a voltaic arc4 ,arc1 ,simple4 ,a voltaic arc produced1 as usual1 between only two electrodes4 #dj ,,standard ,,electrical ,,dictionary4 ,arc1 ,voltaic4 ,the voltaic arc is the arc between two carbon electrodes slightly separated1 which is produced by a current of sufficient strength and involving sufficient potential difference4 ,the pencils of carbon are made terminals in a circuit4 ,they are first placed in contact and after the current is established they are separated a little4 ,the current now seems to jump across the interval in what sometimes appears an arch of light4 ,at the same time the carbon ends become incandescent4 ,as regards the distance of separation with a strong current and high electro-motive force1 the arc may be several inches long4 ,the voltaic arc is the source of the most intense heat and brightest light producible by man4 ,the light is due principally to the incandescence of the ends of the carbon pencils4 ,these are differently affected4 ,the positive carbon wears away and becomes roughly cupped or hollowed2 the negative also wears away1 but in some cases seems to have additions made to it by carbon from the positive pole4 ,all this is best seen when the rods are slender compared to the length of the arc4 ,it is undoubtedly the transferred carbon dust which has much to do with its formation4 ,the conductivity of the intervening air is due partly1 perhaps1 to this1 but undoubtedly in great measure to the intense heating to which it is subject4 ,but the coefficient of resistance of the intervening air is so much higher than that of any other part of the circuit that an intense localization of resistance occurs with corresponding localization of heating effect4 ,this is the cause of the intense light4 ,thus if the carbons are but #a_/cb of an inch apart as in a commercial lamp the resistance may be #a4e ohms4 ,the poor thermal conductivity of the carbon favors the concentration of heat also4 ,the apparent resistance is too great to be accounted for by the ohmic resistance of the interposed air4 ,a kind of thermoelectric effect is produced4 ,the positive carbon has a temperature of about #d1jjj ,c4 7#g1bcb ,f471 the negative from #c1jjj ,c4 7#e1dcb ,f47 to #c1ejj ,c4 7#f1cbb ,f474 ,this difference of temperature produces a counter-electro-motive force which acts to virtually increase the resistance of the arc4 ,the carbon ends of an arc can be projected with the lantern4 ,globules are seen upon them due to melted silica from the arc of the carbon4 ,fig4 #ai4 ,,experimental ,,apparatus ,,for ,,producing ,,the ,,voltaic ,,arc4 #da ,,standard ,,electrical ,,dictionary4 ,areometer4 ,an instrument for determining the specific gravity of a fluid4 ,it consists of an elongated body ballasted so as to float vertically and provided with a mark or a scale4 ,it floats deeper in a light than in a heavy liquid4 ,if it carries but one mark weights are added until that mark is reached1 when the weights required give the specific gravity4 ,or the scale may give the reading directly based upon the depth to which it sinks4 ,areometers are often made of glass1 ballasted with shot or mercury enclosed in their bottom bulb as shown4 ,they are used in regulating battery solutions1 and in watching the charging and discharging of storage batteries4 ,fig4 #bj4 ,,areometer ,fig4 #ba4 ,,bead ,,areometer ,areometer1 ,bead4 ,a tube of glass containing beads of different specific gravities4 ,it has apertures at top and bottom4 ,when immersed in a liquid1 the same fills it1 and the specific gravity within certain limits1 depending on the factors of the beads1 is shown by the beads which float and those which sink4 ,it is used for storage batteries and other purposes where acids and solutions have to be tested4 ,argyrometry4 ,the method of ascertaining the weight and inferentially the thickness of an electroplater's deposit of silver4 ,it is done by weighing the article before and after plating4 ,arm4 ,the four members of a ,wheatstone bridge1 q4 v41 are termed its arms4 ,referring to the diagram of a bridge1 ,p1 ,q1 ,r1 ,s1 are the arms4 ,fig4 #bb4 ,,diagram ,,of ,,wheatstone',s ,,bridge4 ,armature4 7a47 ,a mass or piece of iron or steel1 or a collection of pieces of iron designed to be acted on by a magnet4 ,while nickel or cobalt might be used1 they rarely or never are except in experimental apparatus4 ,the armature of a permanent horse shoe magnet is simply a little bar of soft iron4 ,when the magnet is not in use it is kept in contact with the poles with the idea of retaining its magnetism4 ,it is then said to be used as a keeper4 ,a bar magnet does not generally have an armature4 ,the armature is also used to exhibit the attraction of the magnet4 ,sometimes an armature is made of steel and is permanently magnetized4 ,such an armature1 termed a polarized armature1 is repelled when its like poles are opposed to like poles of the magnet and otherwise is attracted with force due to the sums of the magnetism4 ,if the magnet is sufficiently powerful depolarization of the armature may ensue when like poles are opposed to like poles4 ,polarized armatures are used in various appliances1 magneto generators1 telegraphic instruments and others4 7b7 ,in a dynamo or ,motor the mass of laminated iron or of wire which carries the coils of insulated wires which are caused to rotate in the field of force of the field magnets in order to establish and maintain potential difference with its accompanying current1 or which rotates under the effects of a current in a motor4 7,see ,dynamo ,electric ,generator47 ,the work of the armature core is twofold4 ,it acts as a portion of the magnetic circuit1 conducting the lines of force1 and by virtue of its high permeability or multiplying power concentrating a number of the lines of force through its own substance4 ,to enable it to act with efficiency in this direction it should be made of iron of the highest permeability1 and should approach as closely as possible to the armature cores consistent with leaving space for the wire winding4 ,it next acts as a support for the wires which are to be swept through the field of force4 ,thus it acts both to establish a strong field and then acts as a carrier for the wires which are to be cut by the wires in question4 ,in connection with this subject the different definitions under ,armature1 ,dynamo1 ,commutator1 ,induction and similar topics may be consulted4 7c7 ,see ,armature of ,influence ,machine4 7d7 ,see ,armature of ,leyden ,jar or ,static ,condenser4 #db ,,standard ,,electrical ,,dictionary4 ,armature1 ,bar4 ,an armature in a dynamo or motor whose winding is made up of conductors in the form of bars1 round1 rectangular and of other sections4 ,this type of armature conductor is objectionable as ,foucault currents are produced in it4 ,it is found best to laminate or subdivide low resistance armature windings4 ,transcriber's ,note3 ,foucault currents are also called eddy currents4 ,armature1 ,bipolar4 ,an armature in which two poles are induced by the field4 ,a bipolar field magnet produces a bipolar armature4 ,armature ,bore4 ,the cylindrical space defined by the pole pieces of a dynamo or motor within which the armature rotates4 ,synonym--,armature ,chamber4 #dc ,,standard ,,electrical ,,dictionary4 ,armature1 ,closed ,coil4 ,an armature for a motor or dynamo1 the ends of all of whose coils are united1 so as to be in one closed circuit all the way around4 ,fig4 #bc4 ,,closed ,,coil ,,gramme ,,ring ,,armature4 ,armature ,coil1 or ,coils4 ,the insulated wire wound around the core of the armature of an electric current generator or motor4 ,armature ,core4 ,the central mass of iron on which the insulated wire1 to be rotated in the field of an electric current generator or motor1 is wound4 7,see ,dynamo-electric ,machine and ,motor1 ,electric47 ,armature1 ,cylinder4 ,an armature of the ,gramme ring type1 but longer in the axial direction1 so that its core resembles a long hollow cylinder1 the wire being wound inside and outside as in the ,gramme ring4 7,see ,gramme ,ring47 ,armature1 ,disc4 7a7 ,an armature of a dynamo electric machine or motor in which the coils are wound so as to be flat and are carried on the face of a disc forming the core or part of the core of the armature4 ,s4 ,p4 ,thompson treats it as a modified drum armature extended radially1 the outer periphery corresponding to the back end of the drum4 ,the poles of the field are generally placed to face the side or sides of the disc4 7b7 ,another type of disc armature has its wire wound on bobbins arranged around the periphery of a disc4 ,in disc armatures there is often no iron core1 their thinness enabling this to be dispensed with4 #dd ,,standard ,,electrical ,,dictionary4 ,fig4 #bd4 ,,disc ,,armature ,,of ,,fritsche ,,machine4 ,fig4 #be4 ,,plan ,,of ,,winding ,,pacinotti',s ,,disc ,,armature4 ,armature1 ,discoidal ,ring4 ,in a dynamo an armature of the shape of a ring of considerable radial depth of section as compared to its axial depth4 ,it is generally made of iron ribbon or thin band wound to the proper size4 ,synonym--,flat ,ring ,armature4 #de ,,standard ,,electrical ,,dictionary4 ,armature1 ,drum4 ,an armature for a dynamo or motor1 consisting of a cylinder of iron preferably made up of discs insulated from each other by thin shellacked paper1 or simply by their oxidized surfaces1 and wound with wire parallel to the axis where it lies on the cylindrical periphery and crossing the heads approximately parallel to the diameter4 ,it operates practically on the same principle as a ,gramme ,ring ,armature4 7,see ,gramme ,ring47 ,synonym--,cylindrical ,armature4 ,armature ,factor4 ,the number of conductors on an armature1 counted or enumerated all around its external periphery4 ,armature1 ,hinged4 ,an armature pivoted to the end of one of the legs of an electro-magnet so as to be free to swing and bring its other end down upon the other pole4 ,fig4 #bf4 ,,hinged ,,armatures ,,of ,,club-,,foot ,,electro ,,magnets4 ,armature1 ,hole4 ,an armature whose core is perforated to secure cooling4 ,synonym--perforated ,armature4 ,armature1 ,intensity4 ,an armature wound for high electro-motive force4 ,a term little used at the present time4 ,armature ,interference4 ,a limit to the ampere turns permissible on a given armature is found in the increase of cross magnetizing effect1 q4 v41 the increased lead necessitated1 and the growth of the demagnetizing power4 ,all such perturbing effects are sometimes expressed as armature interference4 #df ,,standard ,,electrical ,,dictionary4 ,armature1 ,load of4 ,the circumflux1 q4 v41 of the armature1 or the ampere turns of the same4 ,the maximum load which can be carried by an armature without sparking is directly proportional to the radial depth of core and to the length of the gap1 and inversely proportional to the breadth of the polar span4 ,armature1 ,multipolar4 ,an armature in which a number of poles greater than two is determined by the field4 ,a multipolar field is employed for its production4 ,armature1 ,neutral4 ,an armature of a magnet or telegraph relay which is not polarized or magnetized4 ,synonym--,non-polarized ,armature--,neutral ,relay ,armature4 ,armature of ,influence ,machine4 ,pieces of paper pasted on the stationary plate of an electric machine of the ,holtz type4 ,armature of ,leyden ,jar or ,static ,condenser4 ,the inner and outer tin-foil coatings of a ,leyden jar or other condenser4 ,armature1 ,open ,coil4 ,an armature of a dynamo or motor on which the coils are not joined in one closed circuit1 but have their ends or some of them separated1 and connected each to its own commutator bar or each set to their own bar4 ,fig4 #bg4 ,,open ,,coil ,,ring ,,armature4 #dg ,,standard ,,electrical ,,dictionary4 ,armature1 ,pivoted4 ,an armature for an electro-magnet mounted on a pivot1 which is at right angles to the yoke or parallel with the legs of the magnet1 so as to be free to rotate4 ,when the magnet is excited the armature is drawn into line or approximately so with its base or yoke4 ,the system is used in some telegraph apparatus4 ,armature ,pockets4 ,spaces or recesses in armatures provided for the reception of the coils4 ,armature1 ,polarized4 ,an armature made of steel or having a steel core to which permanent magnetism has been imparted4 ,such are used in some forms of magneto current generators1 and in telegraphic instruments4 7,see ,relay1 ,polarized47 ,armature1 ,pole4 ,an armature having coils wound on separate poles projecting radially all around the periphery of its central hub or disc1 or projecting internally from a ring-like frame1 their ends facing the field magnet4 ,synonym--,radial ,armature4 ,armature1 ,quantity4 ,an armature of a dynamo or motor wound for current of large quantity4 ,the term is now but little used4 ,armature-,reactions4 ,when an armature is running in an active dynamo a series of reactions is established1 the more important of which are3 ,i4 ,a tendency to cross-magnetize the armature4 ,,ii4 ,a tendency to spark at the brushes4 ,,iii4 ,a tendency for the armature current to demagnetize on account of the lead which has to be given to the brushes4 ,,iv4 ,variations in the neutral points as more or less current is taken from the machine4 ,v4 ,heating of armature1 both core and conductors1 and of pole pieces1 which heating is due to ,foucault currents4 ,armature1 ,revolving1 ,page's4 ,an early form of motor4 ,the field is produced by a permanent magnet4 ,above its poles is a soft iron armature wound with a coil of insulated wire4 ,a two-part commutator with contact springs conveys the current to the coil4 ,the whole is so arranged that the polarity of the armature1 as induced by the coil1 through which a current is passed1 is reversed as its ends sweep by the poles of the magnet4 ,then it is repelled from the poles and swings through #ahj to have its polarity reversed and to go through the next #ahj1 and so on4 ,thus it rotates at a very high rate of speed4 ,in the cut showing the elevation ,a1 ,b1 is the armature2 f1 g1 the springs or brushes2 h1 the commutator with its sections o1 i4 ,in the section of the commutator ,w1 ,w1 designate the springs or brushes1 ,a1 the vertical spindle carrying the armature and commutator1 and ,s1 ,s1 the commutator sections4 #dh ,,standard ,,electrical ,,dictionary4 ,fig4 #bh4 ,,page',s ,,revolving ,,armature4 ,fig4 #bi4 ,,section ,,of ,,commutator ,,of ,,page',s ,,revolving ,,armature4 ,w1 ,w1 ,brushes2 ,a1 ,spindle2 ,s1 ,s1 ,armature ,segments4 ,armature1 ,ring4 ,an armature whose core is in the shape of a ring1 as the ,gramme ,ring ,armature4 7,see ,figs4 #bc #bg47 #di ,,standard ,,electrical ,,dictionary4 ,armature1 ,rolling4 7a7 ,an armature for a permanent horseshoe magnet consisting of a straight cylinder of soft iron on which a heavy wheel is mounted4 ,when the legs of the magnet are inclined downward and the bar is laid across them it rolls down to the poles1 across their ends1 and back up the under side4 ,it is merely a magnetic toy or illustrative experiment4 ,synonym--,wheel ,armature4 7b7 ,another form consists of little bars of iron with brass discs attached to the ends4 ,on placing two of these together and bringing the poles of a magnet near them1 as shown1 they become magnetized with like polarity by induction and repel each other1 rolling away in opposite directions4 ,fig4 #cj4 ,,rolling ,,or ,,wheel ,,armature4 ,fig4 #ca4 ,,rolling ,,armatures4 ,armature1 ,shuttle4 ,the original ,siemens' armature1 now discarded4 ,the core was long and narrow1 and its cross section was nearly of the section of an ,h4 ,the grooves were wound full of wire1 so that the whole formed almost a perfect cylinder1 long and narrow comparatively4 7,see ,winding ,shuttle47 ,synonym--,siemens' ,old ,armature--,girder ,armature--,h ,armature4 ,fig4 #cb4 ,,shuttle ,,or ,h ,,armature4 ,armature1 ,spherical4 ,an armature of a dynamo which is wound on a spherical core1 so as to be almost a sphere4 ,it is employed in the ,thomson-,houston dynamo1 being enclosed in a cavity nearly fitting it1 formed by the pole pieces4 ,armature1 ,stranded ,conductor4 ,a substitute for bar-armatures in which stranded copper wire conductors are substituted for the solid bar conductors1 to avoid ,foucault currents4 7,see ,armature1 ,bar47 #ej ,,standard ,,electrical ,,dictionary4 ,armature1 ,unipolar4 ,an armature of a unipolar dynamo4 7,see ,dynamo ,unipolar47 ,armor of ,cable4 ,the metal covering1 often of heavy wire1 surrounding a telegraph or electric cable subjected to severe usage1 as in submarine cables4 ,synonym--,armature of ,cable4 ,arm1 ,rocker4 ,an arm extending from a rocker of a dynamo or motor1 to which arm one of the brushes is attached4 7,see ,rocker47 ,ordinarily there are two arms1 one for each brush4 ,articulate ,speech4 ,speech involving the sounds of words4 ,it is a definition which has acquired importance in the ,bell telephone litigations1 one contention1 concerning the ,bell telephone patent1 holding that the patentee did not intend his telephone to transmit articulations1 but only sound and music4 ,astatic4 adj4 ,having no magnetic directive tendency due to the earth's magnetism4 ,examples are given under ,astatic ,needle2 ,circuit1 ,astatic2 and ,galvanometer ,astatic4 ,fig4 #cc4 ,,nobili',s ,,pair4 ,,fig4 #cd4 ,,vertical ,,pair ,,astatic ,,combination4 ,astatic ,needle4 ,a combination of two magnetic needles so adjusted as to have as slight directive tendency as possible4 ,such a pair of needles when poised or suspended will hardly tend to turn more to one point of the compass than another4 ,the combination is generally made up of two needles arranged one above the other1 with their poles in opposite directions4 ,this combination is usually called ,nobili's pair4 ,if of equal strength and with parallel magnetic axes of equal length they would be astatic4 ,in practice this is very rarely the case4 ,a resultant axis is generally to be found which may even be at right angles to the long axis of the magnets1 causing them to point east and west4 ,such a compound needle requires very little force to turn it one way or the other4 ,if one of the needles is placed within a coil of insulated wire a feeble current will act almost as strongly to deflect the system as if the other was absent1 and the deflection will only be resisted by the slight directive tendency of the pair of needles4 ,this is the basis of construction of the astatic galvanometer4 ,sometimes coils wound in opposite directions and connected in series1 or one following the other1 surround both needles1 thus producing a still greater effect of deflection4 ,other astatic needles are shown in the cuts below4 ,figures #cc to #ce4 #ea ,,standard ,,electrical ,,dictionary4 ,,fig4 #ce4 ,,simple ,,astatic ,,needle4 ,asymptote4 ,a line continuously approached by a curve1 but which the curve1 owing to its construction or nature of curvature1 can never touch1 be tangent to1 or intersect4 ,atmosphere4 7a7 ,a term applied to the atmospheric pressure as a practical unit of pressure equal to #ae lbs4 to the square inch as generally taken4 ,it is really about #ad4g lbs4 per square inch1 or #a1jcc grams per square centimeter4 7b7 ,air1 q4 v4 ,atmosphere ,residual4 ,the atmosphere left in a vessel after exhaustion4 ,the term may be applied to any gas4 ,in an incandescent lamp after flashing the residual atmosphere consists of hydro-carbons4 ,atmospheric ,electricity4 ,the electricity of the atmosphere1 rarely absent1 but often changing in amount and sign4 ,benjamin ,franklin1 in a memoir published in #agdi1 indicated the method of drawing electricity from the clouds by pointed conductors4 ,in ,june1 #ageb1 he flew a kite and by its moistened cord drew an electric spark from the clouds1 confirming his hypothesis that lightning was identical with the disruptive discharge of electricity4 ,to observe electricity in fine weather a gold-leaf or other electroscope may be connected to the end of a long pointed insulated conductor4 ,the electricity during thunderstorms can be shown by a similar arrangement1 or burning alcohol or tinder gives an ascending current of warm air that acts as a conductor4 ,quite elaborate apparatus for observing and recording it have been devised4 ,atmospheric electricity is usually positive1 but occasionally negative4 ,when the sky is cloudless it is always positive1 increasing with the elevation and isolation of the place4 ,in houses1 streets1 and under trees no positive electricity can be found4 ,in the ,isle of ,arran1 ,scotland1 a rise of #bd to #dh volts per foot of increase in elevation was found by ,sir ,william ,thomson4 ,at sunrise the electrification of the air is feeble1 it increases towards noon and decreases again to reach a second maximum a few hours after sunset4 ,it increases with the barometric pressure generally4 ,in cloudy weather it is sometimes negative and the sign often changes several times in the same day4 ,in a thunderstorm the changes in sign and potential are very rapid4 ,the cause of atmospheric electricity is far from clear4 ,tait attributes it to a contact effect between air and water vapor1 ,solmeke to friction of water vesicles against ice particles in the upper atmosphere1 he first showing that the two may coexist4 ,the cause of the enormous increase of potential producing lightning is attributed to the decreased capacity due to the change of water from cloud vesicles to drops1 thus diminishing the electrostatic capacity of the water in question4 7,see ,lightning47 #eb ,,standard ,,electrical ,,dictionary4 ,atom4 ,the ultimate particle or division of an elementary substance2 the smallest part that can exist in combination1 and one which cannot exist alone4 ,an elementary substance is composed of molecules just as truly as a compound one1 but the atoms in the molecule of an elementary substance are all precisely alike4 ,hence atoms are the units of chemistry1 they have to do with combinations1 but the physical unit1 the smallest particle of matter that can have an independent existence1 is the molecule4 ,the two are often confounded1 especially by writers of a few years ago1 so that by atom the molecule is often meant4 ,there is nothing to be said of their size or mass4 ,all such calculations refer to the molecule1 q4 v41 often spoken of and called the atom4 ,transcriber's note3 ,yet to be discovered3 electron--#ahig 7#e years71 proton--#aibj 7#bh years71 neutron--#aicb 7#cj years71 quark--#aifa 7#fi years74 ,atomic ,attraction4 ,the attraction of atoms for each other1 in virtue of which they combine into molecules2 chemical affinity1 q4 v41 treats principally of this1 although molecular attraction also plays a part in it4 ,atomic ,heat4 ,the product of the atomic weight of a substance by its specific heat4 ,this product is approximately the same1 #f4d2 this approximation is so close that it is of use in determining the valency and atomic weights of substances4 ,the atomic weight of a substance therefore represents the approximate number of gram-calories required to raise one gram-atom1 q4 v41 of such substance through #a ,c4 7#a4h ,f47 ,atomicity4 ,the quantivalence or valency of the atoms2 the number of combination bonds1 or bonds of affinity1 possessed by the atoms of any substance4 ,thus two atoms of hydrogen combine with one atom of oxygen1 and three of oxygen with one of sulphur1 forming saturated compounds4 ,therefore1 taking hydrogen as of single atomicity or a monad1 oxygen is of double atomicity or a dyad1 and sulphur is of six-fold atomicity1 or a hexad4 ,the elements are thus classified into seven orders of atomicities1 thus3 #a1 ,monads or ,univalent elements1 ,hydrogen1 etc4 #b1 ,dyads or ,bivalent ,oxygen1 etc4 #c1 ,triads or ,trivalent ,nitrogen1 etc4 #d1 ,tetrads or ,quadrivalent ,lead1 etc4 #e1 ,pentads or ,quinquivalent ,phosphorous1 etc4 #f1 ,hexads or ,sexivalent ,chromium1 etc4 #g1 ,heptads or ,septivalent ,chromium1 etc4 ,the same element often possesses several atomicities4 ,barium is generally a dyad1 sometimes a tetrad2 nitrogen acts as a monad1 dyad1 triad1 tetrad and pentad4 ,the familiar electrolysis of water1 giving two volumes of hydrogen to one of oxygen1 is one of the illustrations of the theory indicating that two atoms of hydrogen are combined with one of oxygen4 #ec ,,standard ,,electrical ,,dictionary4 ,atomic ,weight4 ,the number expressing the relative weight of the atom of any substance1 that of hydrogen being generally taken as unity4 ,this is the universal system1 although any other element might be taken as the basis of the system4 ,the whole theory of atomic weights is based on the indivisibility of the atom and on the theory of atomicity1 q4 v4 7,see ,equivalents47 ,transcriber's note3 ,the standard is now the isotope carbon-#ab as exactly #ab4 ,attraction4 ,the tendency to approach and adhere or cohere1 shown by all forms of matter4 ,it includes gravitation1 cohesion1 adhesion1 chemical affinity and other forms1 and is opposed by repulsion1 and is sometimes overcome by it1 although it may be assumed to be always present4 ,see the different kinds of attractions under their titles3 ,atomic ,attraction1 ,electro-magnetic ,attraction and ,repulsion1 ,electro ,static ,attraction and ,repulsion1 ,electro-dynamic ,attraction and ,repulsion2 ,magnetic ,attraction and ,repulsion2 ,molar ,attraction4 ,audiometer4 ,an apparatus for obtaining a balance of induction from two coils acting upon a third4 ,the third is placed between the other two and is free to move towards either4 ,a scale is provided to show the extent of its movement4 ,a varying or interrupted current being passed through the two outer coils1 the preponderating current will produce the most induction if the central coil is equidistant4 ,it can always be moved to such a point that there will be no inductive effect1 one counteracting the other4 ,thus its position measures the relative induction4 ,a telephone is in circuit with the intermediate coil and is used to determine when its position is such that no current is induced in it4 ,it is sometimes used as a direct test of hearing4 7,see ,hughes' ,induction ,balance47 ,synonym--,acoutemeter4 ,aura1 ,electrical4 ,the blast of air produced at highly electrified points4 ,aurora4 ,a luminous display seen in the northern heavens in the northern hemisphere1 where it is the ,aurora ,borealis1 and seen in the southern heavens in the southern hemisphere1 where it is called ,aurora ,australis1 or indifferently for either1 the ,aurora ,polaris4 ,it takes the form of pale luminous bands1 rays and curtains varying in color4 ,near the poles they are very numerous4 ,a ,french commission observed #aej auroras in #bjj days4 ,their height is variously estimated at from #ij to #dfj miles2 they are most frequent at the equinoxes and least so at the solstices4 ,there is a secular variation also1 they attain a maximum of occurrence every #aa years together with sun spots1 with a minimum #e or #f years after the maximum4 ,there is also a period of #fj years1 coincident with disturbances in the earth's magnetism4 ,various attempts have been made to account for them4 ,they have a constant direction of arc with reference to the magnetic meridian 7q4 v47 and act upon the magnetic needle2 in high latitudes they affect telegraph circuits violently4 ,there is a strong probability that they represent electric currents or discharges4 ,de la ,rive considers them due to electric discharges between the earth and atmosphere1 which electricities are separated by the action of the sun in equatorial regions4 ,according to ,balfour ,stewart1 auroras and earth currents47q4 v47 may be regarded as secondary currents due to small but rapid changes in the earth's magnetism4 ,the subject is very obscure4 ,stewart treats the earth as representing the magnetic core of an induction coil1 the lower air is the dielectric1 and the upper rarefied and therefore conducting atmosphere is the secondary coil4 ,this makes the aurora a phenomenon of induced currents4 ,then the sun may be regarded as the instigator of the primary changes in the earth's lines of force representing the primary of an induction coil4 ,transcriber's note3 ,solar wind1 streams of electrons and protons1 interacting with the earth's magnetic field causes aurora4 ,neither electrons 7#ahig7 nor protons 7#aibj7 were known in #ahib4 ,the ,soviet satellite ,luna first measured the solar wind in #aiei4 ,even today increased understanding of solar and auroral phenomenon continues4 #ed ,,standard ,,electrical ,,dictionary4 ,austral ,pole4 ,the north pole of the magnet is thus called sometimes in ,france2 the austral pole of a magnet is the one which points towards the north polar regions ,as unlike magnetic poles attract each other1 it is but rational to call the north-seeking pole of the magnet the south or ,austral ,pole4 ,in the same nomenclature the south pole of a magnet1 or the south-seeking pole1 is called the ,boreal ,pole4 ,a4 ,w4 ,g4 ,abbreviation for ,american ,wire ,gauge1 q4 v4 ,axis1 ,electric4 ,the electric axis of a pyroelectric crystal1 such as a tourmaline crystal2 the line connecting the points of greatest pyroelectric excitability4 ,axis of ,abscissa4 ,in a system of rectilinear1 or right angle co-ordinates1 the horizontal axis4 7,see ,co-ordinates47 ,synonym--,axis of ,x4 ,axis of ,ordinates4 ,in a system of rectilinear right angle co-ordinates1 the vertical axis4 7,see ,co-ordinates47 ,synonym--,axis of ,y4 ,azimuth4 ,the angle between the plane of the meridian and the plane of an azimuth circle1 q4 v4 ,azimuth ,circle4 ,a great circle1 whose plane passes through the zenith or point of the heavens directly overhead2 any great circle in whose plane the vertical at the point of observation is included4 ,each celestial body has or determines an azimuth circle4 #ee ,,standard ,,electrical ,,dictionary4 ,b4 7a7 ,abbreviation for ,baum1 a hydrometer scale4 7,see ,baum47 ,thus #aj ,b4 means ten degrees ,baum4 7b7 ,symbol for the coefficient of induced magnetization1 or the number of lines per square centimeter induced in a magnetic circuit or in any specified part of it4 ,b4 ,a4 ,abbreviation for ,british ,association4 ,it is prefixed to standards fixed by the committee of the ,british ,association for the ,advancement of ,science4 ,thus the ,b4 ,a4 ohm means the ,british ,association ohm1 a measure of resistance which is equal to the resistance of a column of mercury #ajd4i centimeters long and one square millimeter area of cross-section4 7,see ,ohm47 ,back ,induction4 ,a demagnetizing force produced in a dynamo armature when a lead is given the brushes4 ,the windings by such setting of the brushes are virtually divided into two sets1 one a direct magnetizing set1 the other a cross magnetizing set4 ,the latter have a component due to the obliqueness of the neutral line1 which component is demagnetizing in its action4 ,back ,shock or ,stroke of ,lightning4 ,a lightning stroke received after the main discharge of the lightning1 and caused by a charge induced in neighboring surfaces by the main discharge4 ,the discharge affects the evenness of distribution of surrounding surfaces so that a species of secondary discharge is required to make even the distribution1 or to supply charge where needed to bind an opposite one4 ,the effects are much lese severe as a rule than those of the main charge1 although the back stroke has caused death4 ,the back stroke is sometimes felt a considerable distance from the place of the original lightning stroke4 ,synonym--,return ,stroke4 ,back ,stroke4 7a7 ,in telegraphy the return stroke of the lever in a telegraph sounder1 striking the end of the regulating screw with a sound distinct from that which it produces on the forward stroke as it approaches the magnet poles4 ,it is an important factor in receiving by ear or sound reading4 7b7 ,see ,back ,shock or ,stroke of ,lightning4 ,balance4 7a7 ,wheatstone's ,bridge1 q4 v41 is sometimes termed the ,electric ,balance4 7b7 ,a suspension or torsion balance is one which includes a filament or pair of filaments to whose lower end or ends are attached a horizontal indicator often called a needle1 or a magnetic needle4 7,see ,torsion ,balance47 7c7 ,see ,induction ,balance1 ,hughes'4 7d7 ,for ,thermic ,balance1 see ,bolometer4 7e7 ,see ,balance1 ,ampere4 #ef ,,standard ,,electrical ,,dictionary4 ,balance1 ,ampere4 ,a class of electrical measuring instruments due to ,sir ,william ,thomson may be grouped under this head4 ,the instrument is a true balance or scales such as used for weighing4 ,it is supported by a torsional wire support in place of knife edges4 ,at each end it carries a circle of wire through which the current to be tested is passed4 ,the torsional wire support enables the current to be carried to these wire rings4 ,above and below each of these rings are two similar rings1 also connected so as to receive the current4 ,they are so connected that the current shall go through them in opposite senses4 ,when a current passes1 therefore1 one of these rings repels and one attracts the balanced ring4 ,the extent of this action measures the intensity of the current4 ,a sliding weight moving along a graduated scale on the balance is used to bring the balance beam into equilibrium when the current is passing4 ,the degree of displacement of this weight gives the strength of the current in amperes4 ,these balances are made for different currents4 ,thus there is a centi-ampere balance1 deka-ampere balance and others1 as well as an ampere balance4 ,balata4 ,a gum used as an insulating material4 ,it is the inspissated juice of a sapotaceous tree1 the bullet tree1 ,mimusops globosa1 of tropical ,america1 from the ,antilles to ,guiana4 ,it is intermediate in character between caoutchouc and gutta percha4 ,it is superior to gutta percha in some respects1 being very slightly acted on by light4 ,synonym--,chicle4 ,b4 ,s44 ,w4 ,g4 ,abbreviation for ,brown ,sharpe ,wire ,gauge2 the regular ,american ,wire ,gauge4 7,see ,wire ,gauge1 ,american47 ,barad4 ,an absolute or fundamental unit of pressure1 equal to one dyne per square centimeter4 ,barometer4 ,an apparatus for measuring the pressure exerted by the atmosphere4 ,it consists1 in the mercurial form1 of a glass tube1 over #ca inches long1 closed at one end1 filled with mercury and inverted1 with its open end immersed in a cistern of mercury4 ,the column falls to a height proportional to the pressure of the atmosphere from #cj to #ca inches at the sea level4 ,the standard barometer is a height of the mercury or of the barometric column of #cj inches or #gfj centimeters1 measured from the surface of the mercury in the cistern4 ,the column of mercury is termed the barometric column4 ,above it in the tube is the ,torricellian vacuum4 ,transcriber's note3 ,more accurately1 #bi4ib inches of mercury or #ad4fif ,,psi4 ,bars of ,commutators4 ,the metal segments of a commutator of a dynamo or motor4 ,they are made of bars of copper1 brass or bronze insulated from one another4 7,see ,commutator47 ,synonyms--,segments1 ,commutator ,segments1 ,commutator ,bars4 #eg ,,standard ,,electrical ,,dictionary4 ,bath4 7a7 ,in electro-plating the solution used for depositing metal as contained in a vat or tank2 as a silver1 copper1 or nickel bath used for plating articles with silver1 copper1 or nickel respectively4 7b7 ,in electro-therapeutics a bath with suitable arrangements1 electrodes and connections for treating patients with electricity4 ,it is termed an electric bath or electro-therapeutic bath4 ,bath1 ,bipolar ,electric4 ,in electro-therapeutics a bath in which the electrodes are both immersed in the water4 ,the patient placed between them receives part of the discharge4 ,the electrodes are large copper plates1 termed shovel electrodes4 ,bath1 ,electric ,shower4 ,an electro-medical shower bath4 ,the patient is placed on a metallic stove or support connected to one of the electric terminals4 ,water slightly alkaline is showered upon him4 ,the other electrode is in connection with the water4 ,the rain of drops and streamlets is the conductor of the current or discharge4 ,bath1 ,multipolar ,electric4 ,an electro-medical bath with a number of electrodes instead of two4 ,bath1 ,stripping4 ,in electro-plating a solution used for dissolving and thus removing the plating from any object4 ,the stripping bath is of the same general type as the plating bath for the same metal as the one to be dissolved4 ,the object to be stripped is made the anode of a plating circuit1 and as the current acts the old plating is attacked and dissolves1 leaving the body of the article bare4 ,it is simply the operation of plating reversed4 ,the same term is applied to baths acting by simple solution4 ,stripping baths are described under the different metals as ,silver ,bath1 ,stripping--,gold ,bath1 ,stripping4 ,bath1 ,unipolar ,electric4 ,an electro-medical bath1 in which only one electrode connects with the water of the bath4 ,the second electrode is supported above the bath4 ,the patient touches this while in the water whenever electric action is desired4 ,,fig4 #cf4 ,,three ,,wire ,,moulding ,,or ,,batten4 ,,fig4 #cg4 ,,two ,,wire ,,moulding ,,or ,,batten4 #eh ,,standard ,,electrical ,,dictionary4 ,batten4 ,a strip of wood grooved longitudinally for holding wires in wiring apartments for electric light or power4 ,in use they are fastened to the wall1 grooves inward1 or else grooves outward1 with the wires lying in the grooves and covered with the covering strip4 ,for two wire work each batten contains two grooves2 for the three wire system it contains three grooves4 ,synonym--,moulding4 ,battery4 ,a combination of parts or elements for the production of electrical action4 ,the term is principally applied to voltaic batteries1 but there are also magnetic batteries1 batteries of ,leyden jars1 and other combinations1 described in their places1 which come under this category4 ,transcriber's note3 ,a group of similar items such as questions1 machines1 parts1 guns1 or electric cells4 ,battery1 ,acetic ,acid4 ,a battery whose active solution or excitant is acetic acid or vinegar4 ,this acid has been used by ,pulvermacher in his medical battery1 as being a substance found in every household in the form of vinegar4 ,it is now but little used4 ,battery1 ,alum4 ,a battery using as excitant a solution of alum4 ,this battery has had some application for electric clocks1 but only to a limited extent4 ,fig4 #ch4 ,,balloon ,,or ,,flask ,,battery4 ,battery1 ,aluminum4 ,a battery in which aluminum is the negative plate and aluminum sulphate the excitant4 ,it is mounted like the gravity battery4 ,its electro-motive force is #j4b volt4 #ei ,,standard ,,electrical ,,dictionary4 ,battery1 ,bagration4 ,a battery with zinc and carbon electrodes immersed in earth sprinkled with sal ammoniac 7ammonium chloride74 ,the copper is preferably first immersed in sal ammoniac solution and dried1 until a green layer is formed on its surface4 ,the battery is highly praised for its constancy by ,de la ,rive1 but may be regarded as obsolete4 ,battery1 ,balloon4 ,a form of gravity battery into whose centre a globular flask1 ,b1 is inverted1 which is filled before inversion with copper sulphate1 of which #b lbs4 are used1 and water1 so as to remain full4 ,this acts as a reservoir of copper sulphate1 which it constantly supplies4 ,the glass jar is closed with a perforated wooden cover4 ,battery1 ,banked4 7a7 ,a battery arranged to feed a number of separate circuits4 7b7 ,a battery connected in parallel or in multiple arc4 ,battery1 ,bichromate4 ,a battery with amalgamated zinc and carbon plates1 with an exciting fluid composed of sulphuric acid1 water1 and potassium bichromate4 ,for formula of such solutions see ,electropoion ,fluid--,kookogey's ,solution--,poggendorff's ,solution--,trouv's ,solution--,delaurier's ,solution1 and others4 7,see ,index47 ,battery1 ,bunsen4 ,a two fluid porous cell battery4 ,the negative plate is carbon1 the positive plate1 amalgamated zinc4 ,the depolarizer is nitric acid or electropoion fluid1 q4v41 in which the carbon is immersed4 ,the last named depolarizer or some equivalent chromic acid depolarizing mixture is now universally used4 ,the excitant is a dilute solution of sulphuric acid4 ,originally the carbon was made cylindrical in shape and surrounded the porous cups1 in which the zinc was placed4 ,this disposition is now generally reversed4 ,the electro-motive force is #a4i volts4 ,the depolarizing solution is placed in the compartment with the carbon4 ,the excitant surrounds the zinc4 ,fig4 #ci4 ,,bunsen',s ,,battery4 #fj ,,standard ,,electrical ,,dictionary4 ,battery1 ,cadmium4 ,a battery in which cadmium is the negative plate1 sulphate of cadmium solution the excitant and depolarizer1 and zinc the positive plate4 ,electro-motive force1 4#ca volt or about one third of a ,daniell cell4 ,it is mounted like a gravity battery4 ,battery1 ,callan4 ,a modification of ,grove's battery4 ,platinized lead is used for the negative plate1 and as a depolarizer a mixture of #d parts concentrated sulphuric acid1 #b parts of nitric acid1 and #b parts of a saturated solution of potassium nitrate4 7,see ,battery1 ,grove's47 ,battery1 ,camacho's4 ,a battery with carbon negative and amalgamated zinc positive electrodes4 ,the carbon is contained in a porous cup1 packed with loose carbon4 ,electropoion or other fluid of that type serves as excitant and depolarizer1 and is delivered as shown from cell to cell by syphons4 ,fig4 #dj4 ,,camacho',s ,,battery4 ,battery1 ,carr's4 ,a ,daniell battery for whose porous cup a vessel or species of sack made of parchment paper is substituted4 ,the battery has been used for electric light1 and has been run for #bjj successive hours1 by replacing every #bd hours part of the zinc sulphate solution by water4 #fa ,,standard ,,electrical ,,dictionary4 ,battery1 ,cautery4 ,a battery used for heating a platinum wire or other conductor used for cauterization in electro-therapeutics4 ,the term is descriptive1 not generic4 ,battery1 ,chloric ,acid4 ,a battery of the ,bunsen type in which an acidulated solution of potassium chlorate is used as depolarizer4 ,battery1 ,chloride of ,lime4 ,a battery in which bleaching powder is the excitant4 ,the zinc electrode is immersed in a strong solution of salt1 the carbon in a porous vessel is surrounded with fragments of carbon and is packed with chloride of lime 7bleaching powder74 ,there is no action on open circuit4 ,it has to be hermetically sealed on account of the odor4 ,its electro-motive force is--initial1 #a4fe volts2 regular1 #a4e volts4 ,synonym--,niaudet's ,battery4 ,battery1 ,chromic ,acid4 ,properly a battery in which chromic acid is used as a depolarizer4 ,it includes the bichromate battery4 7,see ,battery1 ,bichromate47 ,battery1 ,closed ,circuit4 ,a battery adapted by its construction to maintain a current on a closed circuit for a long time without sensible polarization4 ,the term is merely one of degree1 for any battery becomes exhausted sooner or later4 ,as examples the ,grove1 ,bunsen or ,daniell batteries may be cited4 #fb ,,standard ,,electrical ,,dictionary4 ,fig4 #da4 ,,column ,,battery4 ,battery1 ,column4 ,the original ,volta's pile4 ,it consists of a series of compound circular plates1 the upper or lower half1 ,a1 copper2 the other1 ,z1 of zinc4 ,between each pair of plates some flannel or cloth1 u1 u1 is laid1 which is saturated with dilute acid4 ,as shown in the cut1 the parts are laid up in two piles1 connected at the top with a bar1 c1 c1 and with vessels of acidulated water1 b1 b1 as electrodes4 ,the great point in setting it up is to be sure that no acid runs from one disc of flannel to the next over the outside of the plates1 as this would create a short circuit4 ,the plates are best compound1 being made up of a zinc and a copper plate soldered together4 ,they may1 however1 be separate1 and merely laid one on the other4 ,in such case great care must be taken to admit no acid between them4 ,volta's pile is no longer used1 except occasionally4 ,trouv's blotting paper battery 7see ,battery1 ,trouv's7 is a relic of it1 and the same is to be said for ,zamboni's dry pile4 ,it rapidly polarizes1 the flannel retains but little acid1 so that it is soon spent1 and it is very troublesome to set up4 ,great care must be taken to have the cloth discs thoroughly saturated1 and wrung out to avoid short circuiting by squeezing out of the acid4 ,battery1 ,d',arsonval's4 ,a battery of the ,bunsen type1 differing therefrom in the solutions4 ,as excitant in which the zinc electrode is immersed1 the following solution is used3 ,water1 #bj volumes2 ,sulphuric ,acid 7purified by shaking with a little olive or similar oil71 #a volume2 hydrochloric acid1 #a volume4 ,as polarizer in which the carbon is immersed the following is used3 ,nitric acid1 #a volume2 hydrochloric acid1 #a volume2 water acidulated with #a_/bjth sulphuric acid1 #b volumes4 ,battery1 de la ,rue4 ,a battery with zinc positive and silver negative electrode2 the depolarizer is silver chloride2 the excitant common salt or ammonium chloride4 ,the cut shows one of its forms of construction4 ,the right hand portion of the cut1 ,fig4 #db1 shows the zinc perforated at ,c for the connection from the next silver plate4 ,the next to it is the negative electrode of silver around which a mass of silver chloride is cast in cylindrical form4 ,a is a parchment paper cylinder with two holes near its top1 through which the silver wire of the negative electrode is threaded1 as shown in ,b4 ,a solution of #bc parts ammonium chloride in #a1jjj parts of water is the approved excitant4 ,its electro-motive force is #a4jc volts4 ,the jars are closed with paraffin4 ,fig4 #db4 ,,de ,,la ,,rue',s ,,battery4 #fc ,,standard ,,electrical ,,dictionary4 ,battery1 ,dry4 7a7 ,a form of open circuit battery in which the solutions by a mass of zinc oxychloride1 gypsum1 or by a gelatinous mass such as gelatinous silica1 or glue jelly1 are made practically solid4 ,numbers of such have been patented1 and have met with considerable success4 7b7 ,zamboni's dry pile1 q4 v41 is sometimes termed a dry battery4 ,battery1 ,element of4 ,a term applied sometimes to a single plate1 sometimes to the pair of plates1 positive and negative1 of the single couple4 ,battery1 ,faradic4 ,a term applied1 not very correctly however1 to apparatus for producing medical faradic currents4 ,it may be an induction coil with battery1 or a magneto-generator worked by hand4 ,battery1 ,ferric ,chloride4 ,a battery of the ,bunsen type1 in which a solution of perchloride of iron 7ferric chloride7 is used for the depolarizing agent4 ,a little bromine is added with advantage4 ,the depolarizing agent recuperates on standing1 by oxidation from the oxygen of the air4 ,battery1 ,fuller's4 ,a battery of the ,bunsen type4 ,the zinc plate is short and conical1 and rests in the porous jar into which some mercury is poured4 ,an insulated copper wire connects with the zinc4 ,a plate of carbon is in the outer jar4 ,the solutions are used as in the ,bunsen battery4 ,synonym--,mercury ,bichromate ,battery4 ,battery1 ,gas4 7a7 ,a battery whose action depends on the oxidation of hydrogen as its generating factor4 ,it was invented by ,grove4 ,plates of platinum are immersed in cups of dilute acid1 arranged as if they were plates of zinc and carbon1 in an ordinary battery4 ,each plate is surrounded by a glass tube sealed at the top4 ,the plates are filled with acid to the tops4 ,through the top the connection is made4 ,a current from another battery is then passed through it1 decomposing the water and surrounding the upper part of one set of plates with an atmosphere of oxygen and of the other with hydrogen4 ,considerable quantities of these gasses are also occluded by the plates4 ,on now connecting the terminals of the battery1 it gives a current in the reverse direction of that of the charging current4 ,this battery1 which is experimental only1 is interesting as being the first of the storage batteries4 7b7 ,upward's ,chlorine ,battery and any battery of that type 7see ,battery1 ,upward's17 is sometimes termed a gas battery4 #fd ,,standard ,,electrical ,,dictionary4 ,battery ,gauge4 ,a pocket or portable galvanometer for use in testing batteries and connections4 ,battery1 ,gravity4 ,a battery of the ,daniell type1 in which the porous cup is suppressed and the separation of the fluids is secured by their difference in specific gravity4 ,a great many forms have been devised1 varying only in details4 ,the copper plate1 which is sometimes disc shaped1 but in any case of inconsiderable height1 rests at the bottom of the jar4 ,near the top the zinc plate1 also flat or of slight depth1 is supported4 ,as exciting liquid a strong solution of copper sulphate lies at the bottom of the jar4 ,this is overlaid by a solution of zinc sulphate1 or sodium sulphate1 which must be of considerably less specific gravity than that of the copper sulphate solution4 ,in charging the jar one-tenth of a saturated solution of zinc sulphate mixed with water is sometimes used as the upper fluid4 ,this may be first added so as to half fill the jar4 ,the strong solution of copper sulphate may then be added with a syphon or syringe underneath the other so as to raise it up4 ,from time to time copper sulphate in crystals are dropped into the jar4 ,they sink to the bottom and maintain the copper sulphate solution in a state of saturation4 ,fig4 #dc4 ,,gravity ,,battery ,,of ,,the ,,trouv-,,callaud ,,type4 ,if the battery is left on open circuit the liquids diffuse1 and metallic copper precipitates upon the zincs4 ,this impairs its efficiency and creates local action4 ,as long as the battery is kept at work on closed circuit work but little deposition1 comparatively speaking1 occurs4 ,from time to time1 in any case1 the zinc plates are removed and scraped1 so as to remove the copper which inevitably forms on their surface4 ,care must be taken that the zinc sulphate solution1 which is constantly increasing in strength1 does not get so strong as to become of as high specific gravity as the copper sulphate solution4 ,from time to time some of the upper solution is therefore removed with a syphon or syringe and replaced with water4 ,an areometer is useful in running this battery4 #fe ,,standard ,,electrical ,,dictionary4 ,battery1 ,grenet4 ,a plunge battery with zinc positive and carbon negative electrodes4 ,electropoion or other chromic acid or bichromate solution is used as depolarizer and excitant4 ,the zinc plate alone is plunged into and withdrawn from the solution4 ,fig4 #dd4 ,,grenet',s ,,battery4 ,fig4 #de4 ,,grove',s ,,battery4 ,battery1 ,grove's4 ,a two fluid galvanic battery4 ,a porous cup has within it a riband of platinum1 which is the negative plate2 amalgamated zinc in the outer jar is the positive plate4 ,dilute sulphuric acid 7#aj per cent4 solution7 is placed in the outer jar1 and strong nitric acid 7#dj ,b47 as a depolarizer in the porous cups4 ,its ,e4 ,m4 ,f4 is #a4if volts4 ,it is objectionable1 as it gives off corrosive nitrous fumes4 ,these are produced by the oxidation of the nascent hydrogen by the nitric acid1 by the following reaction3 #c ,h ,h ,n ,o#c #b ,h#b ,o ,n ,o4 ,there are other reactions1 one of which results in the formation of ammonia by the reduction of the nitric acid radical by the hydrogen4 ,ammonium can be detected in the spent liquids4 #ff ,,standard ,,electrical ,,dictionary4 ,battery1 ,hydrochloric ,acid4 ,a battery in which hydrochloric acid is used as the excitant4 ,many attempts have been made to use this acid in batteries1 but the volatile nature of the acid causes the production of so much odor with corrosive fumes that it has never come into use4 ,battery1 ,lead ,chloride4 ,a battery of the lead sulphate type in which lead chloride is the depolarizer4 ,it has had no extended use4 ,battery1 ,lead ,sulphate4 ,a battery similar to ,mari ,davy's battery or the gravity battery1 but using lead sulphate as depolarizer and excitant4 ,lead1 copper or tin is the material of the negative plate4 ,becquerel used the lead sulphate as a solid cylindrical mass surrounding a lead rod #a_/e to #a_/d inch in diameter4 ,one part of common salt may be mixed with #e parts of the lead sulphate4 ,the electro-motive force is about #j4e volt4 ,the resistance is very high4 ,battery1 ,leclanch4 ,an open circuit battery with porous cup4 ,in the outer jar is a zinc rod2 a carbon plate is placed in the porous cup4 ,the latter is packed with a mixture of clean powdered manganese binoxide as depolarizer1 and graphite in equal volumes4 ,a strong solution of ammonium chloride 7sal ammoniac7 is placed in the outer jar4 ,it is only used on open circuit work4 ,its electromotive force is #a4dh volts1 when not polarized4 ,the reaction is supposed to be about the following3 #b ,n ,h#d ,cl #b ,mn ,o#b ,zn ,zn ,cl#b #b ,n ,h#c ,h#b #j ,m#b ,o#c ,the battery rapidly weakens on open circuit1 but quickly recuperates4 ,there is another form of this battery1 termed the agglomerate battery4 7,see ,battery1 ,leclanch ,agglomerate47 ,fig4 #df4 ,,leclanch ,,battery4 ,battery1 ,leclanch ,agglomerate4 ,a form of the ,leclanch in which the porous jar is suppressed4 ,cakes made of a mixture of carbon1 #eb parts2 manganese binoxide1 #dj parts2 gum lac1 #e parts2 potassium bisulphate1 #c parts1 compressed at #cjj atmospheres1 at a temperature of #ajj ,c4 7#bab ,f471 are fastened by ,india rubber bands or otherwise against the carbon plate4 ,these constitute the depolarizer4 ,various shapes are given the carbon and depolarizing agglomerates4 ,battery1 ,local4 ,a battery supplying a local circuit 7see ,circuit4 ,local74 ,the current is governed by the relay situated on the main line and operated by its current4 ,battery1 ,main4 ,the battery used in operating the main line4 ,it is usually applied to telegraphy4 ,its function is then to supply current for working relays1 which in turn actuate the local circuits4 ,main and local circuits and batteries are also used in the automatic block system of railroad signalling4 #fg ,,standard ,,electrical ,,dictionary4 ,battery1 ,mari ,davy's4 ,a two fluid porous cup battery with carbon negative plate1 zinc positive plate1 and mercury sulphate1 a nearly insoluble salt1 as depolarizer and excitant4 ,mercurous or mercuric sulphates have been used in it4 ,its electromotive force is #a4e volts4 ,the local action and waste1 owing to the slight solubility of the mercury compounds1 is very slight4 ,if used on close circuit it becomes polarized4 ,it is also subject under extreme circumstances to reversal of polarity1 zinc becoming deposited upon the carbon1 and there forming a positive electrode4 ,in using the cells in series the level of liquid in all must be the same1 otherwise the cell in which it is lowest will become polarized and exhausted4 ,modifications of this battery on the lines of the gravity battery have been constructed4 ,synonym--,sulphate of ,mercury ,battery4 ,battery1 ,maynooth's4 ,a battery of the ,bunsen type1 with cast iron negative plate4 ,the iron takes the passive form and is not attacked4 ,battery1 ,medical4 ,a term applied very indiscriminately to medical current generators1 and to medical induction coils1 or to any source of electricity1 static or current1 for medical application4 #fh ,,standard ,,electrical ,,dictionary4 ,battery1 ,meidinger's4 ,a variety of ,daniell cell of the gravity type4 ,the plates are cylindrical4 ,the zinc plate lies against the upper walls of the vessel4 ,the copper plate of smaller diameter rests on the bottom4 ,a large tube1 with an aperture in its bottom1 is supported in the centre and is charged with copper sulphate crystals4 ,the cup is filled with a dilute solution of ,epsom salts 7magnesium sulphate7 or with dilute sulphuric acid4 ,battery ,mud4 ,a deposit of mud-like character which forms in gravity batteries and which consists of metallic copper precipitated by the zinc4 ,it indicates wasteful action4 ,battery1 ,multiple-connected4 ,a battery connected in parallel1 all the positive plates being connected to one electrode1 and all the negative to another4 ,battery1 ,nitric ,acid4 ,a battery in which nitric acid is used as the excitant4 ,owing to its cost and volatility this acid has been but little used in batteries1 other than as a depolarizer4 ,in ,grove's battery 7see ,battery1 ,grove's7 it has been thus used4 ,battery of ,dynamos4 ,a number of dynamos may be arranged to supply the same circuit4 ,they are then sometimes termed as above1 a ,dynamo ,battery4 ,they may be arranged in series or in parallel or otherwise combined4 ,battery of ,leyden ,jars4 ,to produce the quantity effect of a single large ,leyden jar with a number of small ones they are often connected in parallel and termed a battery4 ,in such case the inner coatings are all connected by regular bar conductors1 and the outside coatings are also all in connection4 ,they are conveniently placed in a box or deep tray whose inner surface is lined with tinfoil1 with an outside connection for grounding1 etc4 ,the cascade1 q4 v41 arrangement is not so generally termed a battery4 ,battery1 ,open ,circuit4 ,a battery adapted for use in open circuit work4 ,its main requirement is that it shall not run down1 or exhaust itself when left on open circuit4 ,the ,leclanch battery is very extensively used for this work4 ,its action is typical of that of most open circuit batteries4 ,it is without any action on open circuit4 ,it is very quickly exhausted on closed circuit1 but recuperates or depolarizes quite soon when on open circuit4 ,it is always in condition for a momentary connection1 but useless for steady work4 ,battery1 ,oxide of ,copper4 ,a battery with zinc positive and iron negative electrodes4 ,the excitant is a #cj or #dj per cent4 solution of sodium or potassium hydrate 7caustic soda or caustic potash74 ,the depolarizer is copper oxide4 ,in action the copper is gradually reduced to the metallic state4 ,the iron element is often the containing vessel4 ,the battery is practically inactive on open circuit4 ,its electro-motive force varies from 4#ge to 4#ij volt4 ,to prevent the formation of sodium or potassium carbonate the cell should be closed1 or else the liquid should be covered with mineral oil4 ,synonyms--,lalande ,chaperon ,battery--,lalande-,edison ,battery4 #fi ,,standard ,,electrical ,,dictionary4 ,battery1 ,peroxide of ,lead4 ,a battery in which peroxide of lead 7lead binoxide7 is the depolarizer4 ,it is a sort of predecessor of the present secondary battery4 ,battery1 ,platinized ,carbon4 ,a modification of ,smee's battery1 in which platinized carbon is used for the negative plates4 ,before polarization the ,e4 ,m4 ,f4 is equal to that of ,smee's battery4 ,polarization reduces its electro-motive force one-half4 ,battery1 ,plunge4 ,a battery whose plates are mounted so as to be immersed in the battery cups or cells1 when the battery is to be used1 and withdrawn and supported out of the cups when not in use4 ,the object is to prevent wasting of the plates by standing in the solution4 ,it is a construction generally used with sulphuric acid--chromic acid solution and amalgamated zinc and carbon plates4 ,battery1 ,pneumatic4 ,a battery arranged to have air blown through the solution to assist diffusion and depolarization4 ,it is a construction applied to chromic acid or bichromate batteries4 ,battery1 ,primary4 ,a battery in which the current is supplied by the solution of one of the plates by the solution4 ,the term distinguishes it from a secondary or storage battery4 ,battery1 ,pulvermacher's ,electro-,medical4 ,in this battery1 the electrodes were zinc and copper wires wound upon small pieces of wood4 ,dilute vinegar was used as the excitant1 because it could be found in every household4 ,formerly the battery had great success4 ,it is now little used4 ,battery1 ,sal ,ammoniac4 ,batteries in which a solution of ammonium chloride is the excitant2 they are very extensively used on open circuit work4 7,see ,battery1 ,leclanch47 ,the crystals formed in these batteries have been analyzed and found to consist of ammonium zinc chloride1 #c ,zn ,cl#b1 #h ,n ,h#c1 #d ,h#bj4 ,battery1 ,salt1 or ,sea ,salt4 ,batteries in which a solution of sodium chloride or common salt is the excitant1 have been largely used1 especially for telegraphic purposes4 ,the ,swiss telegraphs use a carbon-zinc combination with salt and water as the excitant4 ,the batteries are sometimes mounted as plunge batteries4 ,they are exhausted by short circuiting after some hours1 but recuperate on standing4 ,the zinc is not amalgamated4 #gj ,,standard ,,electrical ,,dictionary4 ,battery1 ,sand4 ,a battery whose cells are charged with sand saturated with dilute acid4 ,it prevents spilling of acid4 ,it is now practically obsolete4 ,fig4 #dg4 ,,secondary ,,battery4 ,battery1 ,secondary4 ,a voltaic battery whose positive and negative electrodes are formed or deposited by a current from a separate source of electricity by electrolysis4 ,on disconnection the battery is ready to yield a current1 in the reverse direction of that of the charging current4 ,the usual type has lead plates on one of which lead binoxide and on the other of which spongy lead is formed4 ,the lead binoxide seems to be the negative element1 and it also acts as the depolarizer4 ,the spongy lead is the positive electrode4 ,the solution is dilute sulphuric acid of specific gravity #a4ag4 ,the action consists first in the oxidation of the spongy lead4 ,the hydrogen set free by the reaction1 and which by electrolytic transfer goes to the other plate1 reduces the lead binoxide to protoxide4 ,the sulphuric acid then attacks the oxides and converts the oxides into sulphates4 ,the charging process consists in sending a current in the reverse direction through the battery4 ,if there are several cells they are arranged in series1 so that each one receives the same intensity of current4 ,an electrolytic decomposition takes place1 the lead sulphate on one plate is reduced to metallic lead1 and that on the other plate is oxidized to lead binoxide4 ,it is then ready for use4 #ga ,,standard ,,electrical ,,dictionary4 ,the plates in a lead plate battery are of very large area per cell1 and are placed close together4 ,sometimes1 as in ,plant's battery1 large flat plates are laid together with a separating insulator between them1 and are then rolled into a spiral4 ,sometimes1 the most usual arrangement1 the plates are in sets1 the positive and negative ones alternating1 and each cell containing a number of plates4 ,to secure a good quantity of active material1 the plates are sometimes perforated1 and the perforations are filled with oxide of lead4 ,this gives a good depth of material for the charging current to act on1 and avoids the necessity for a tedious forming1 q4 v4 ,the electro-motive force of such a battery per cell is #b volts4 ,its resistance may only be one or two-hundredths of an ohm4 ,an intense current of many amperes can be supplied by it1 but to avoid injuring the cell a current far less than the maximum is taken from it4 ,to charge it1 a slightly greater electro-motive force1 the excess being termed spurious voltage1 is required4 ,fig4 #dh4 ,,siemens' ,,and ,,halske',s ,,paper ,,pulp ,,battery4 #gb ,,standard ,,electrical ,,dictionary4 ,battery1 ,secondary1 ,plante's4 ,plante's secondary battery is one of the earlier forms of storage battery1 but has had much success4 ,two lead plates1 large in area and close together but not touching1 are formed1 by exposure to an electrolyzing current of electricity in one direction1 while they are immersed in dilute sulphuric acid4 ,this converts the surface of one plate into binoxide4 ,the cell is then allowed to discharge itself almost completely1 when the charging current is again turned on4 ,this process is repeated over and over again1 until the surfaces of the plates are considerably attacked1 one plate1 however1 being maintained in a state of oxidation4 ,after a few days of this operation a period of rest is allowed between the reversals1 which sets up a local action on the oxidized plate1 between the metallic lead of the plate1 and its coating of binoxide4 ,this causes the lead to be attacked1 under the influence of the local couple1 and sulphate of lead is formed1 which1 ultimately1 by the charging current is converted into peroxide4 ,these operations produce an exceedingly good battery4 ,the process described is termed forming4 ,the plates separated by strips of insulating material are generally wound into a double spiral4 ,battery1 ,siemens' and ,halske's4 ,a ,daniell battery of peculiar shape4 ,the copper1 ,c1 is at the bottom of the glass jar1 ,a4 ,the inner jar1 ,k1 has the form of a bell1 and supports a mass of paper pulp1 which is dampened with sulphuric acid4 ,the zinc1 ,z1 rests on top of the mass of pulp4 ,the battery is very durable1 but of high resistance4 ,battery1 ,sir ,william ,thomson's4 ,a form of ,daniell battery1 of the gravity type4 ,the receptacles are shallow wooden trays lined with lead4 ,a thin plate of copper rests on the bottom4 ,the zinc plate is of gridiron shape1 and rests on wooden blocks which support it in a horizontal position above the copper4 ,one tray is placed on top of the other1 the upper tray resting on the corners of the zinc plate which rise above the level of the top of the flat vessel4 ,thus connection is assured without wires or binding posts4 ,it is charged like a gravity battery4 ,the density of the zinc sulphate solution should be between #a4aj and #a4cj4 ,the circuit must be kept closed to prevent deposition of metallic copper on the zinc4 ,the entire disposition of the battery is designed to reduce resistance4 ,battery1 ,skrivanow4 ,a pocket battery of the ,de la ,rue type1 with a solution of #ge parts caustic potash in #ajj parts of water as the excitant4 ,the silver chloride is contained in a parchment paper receptacle4 ,its electro-motive force is #a4de to #a4e volts4 ,battery1 ,smee's4 ,a single fluid combination1 with zinc positive plate1 and a plate of silver1 coated with platinum black1 for the negative plate4 ,the finely divided platinum affords a surface from which the hydrogen bubbles instantly detach themselves1 thus preventing polarization4 ,the liquid is a mixture of one part sulphuric acid to seven parts of water4 ,for the negative plate silver-plated copper1 coated with platinum black1 is used4 ,electromotive force1 4#dg volt4 ,fig4 #di4 ,,smee',s ,,battery4 #gc ,,standard ,,electrical ,,dictionary4 ,fig4 #ej4 ,,spiral ,,battery1 ,,or ,,hare',s ,,deflagrator4 ,battery1 ,spiral4 ,a battery whose plates of thin zinc and copper are wound into a spiral so as to be very close1 but not touching4 ,dilute sulphuric acid is the excitant4 ,it is now practically obsolete4 ,synonyms--,calorimeter--,hare's ,deflagrator4 ,battery1 ,split4 ,a battery of a number of voltaic cells1 connected in series1 with their central portion grounded or connected to earth4 ,this gives the ends of opposite potentials from the earth1 and of difference therefrom equal to the product of one-half of the number of cells employed1 multiplied by their individual voltage4 ,battery ,solutions1 ,chromic ,acid4 ,a number of formulae have been proposed for these solutions4 7,see ,electropoion ,fluid--,kookogey's ,solution--,poggendorff's ,solution-- ,trouv's ,solution--,delaurier's ,solution--,chutaux's ,solution--,dronier's ,salt--,tissandier's ,solution47 ,battery1 ,trough4 ,a battery whose elements are contained in a trough1 which is divided by cross-partitions so as to represent cups4 ,a favorite wood for the trough is teak1 which is divided by glass or slate partitions4 ,marine glue or other form of cement is used to make the joints tight4 ,for porous cup divisions plates of porous porcelain or pottery are placed across1 alternating with the impervious slate partitions4 ,battery1 ,trouv's ,blotting ,paper4 ,a battery of the ,daniell type in which the solutions are retained by blotting paper4 ,a considerable thickness of blotting paper lies between the two plates4 ,the upper half of the thickness of the blotting paper is saturated with a solution of zinc sulphate1 on which the zinc plate rests4 ,the lower half of the paper is saturated with copper sulphate solution1 and this rests upon the copper plate4 ,fig4 #ea4 ,,trouv',s ,,blotting ,,paper ,,battery4 #gd ,,standard ,,electrical ,,dictionary4 ,battery1 ,tyer's4 ,a modification1 as regards the positive element1 of ,smee's battery1 q4 v4 ,the bottom of the battery jar contains a quantity of mercury in which pieces of zinc are thrown1 and this constitutes the positive element4 ,a ball of zinc at the end of an insulated copper wire affords the connection with the zinc and mercury4 ,its great advantage is that the smallest scraps of zinc can be used in it1 by being dropped into the mercury4 ,the negative plate is platinized silver2 the exciting liquid1 dilute sulphuric acid4 ,fig4 #eb4 ,,tyer',s ,,battery4 #ge ,,standard ,,electrical ,,dictionary4 ,fig4 #ec4 ,,section ,,of ,,upward',s ,,battery4 ,fig4 #ed4 ,,elevation ,,of ,,upward',s ,,battery4 ,battery1 ,upward's4 ,a primary voltaic cell1 the invention of ,a4 ,rene ,upward4 ,referring to the cuts1 the positive plate4 ,z1 is of cast zinc2 it is immersed in water1 in a porous cup1 ,b4 ,outside of the porous cup and contained in the battery jar are two carbon plates1 ,c1 ,c1 connected together4 ,the rest of the space between the porous cup and battery jar is packed with crushed carbon1 and the top is cemented4 ,chlorine gas is led by a pipe1 ,d1 into the outer cell4 ,it diffuses through the fine carbon1 dissolves in the water1 and so finds its way to the zinc1 which it attacks1 directly combining therewith1 and forming zinc chloride 7,zn #b ,cl ,zn ,cl #b74 ,such of the chlorine as is not absorbed finds its way by an outlet tube1 ,e1 to the next cell4 ,arrangements are provided for generating chlorine gas as required4 ,the high specific gravity of the gas is utilized in regulating its distribution through the cells4 ,the electro-motive force of the cell is #b4a volts4 ,a cell #aa4e by #e4e inches and #ab4e inches deep has a resistance of #j4b ohm4 ,an overflow pipe1 ,f1 with faucet1 ,t1 is supplied to withdraw the solution of zinc chloride as it accumulates4 #gf ,,standard ,,electrical ,,dictionary4 ,battery1 ,varley's4 ,a ,daniell battery of the ,siemens' and ,halske's type 7see ,battery1 ,siemens' and ,halske's71 in which zinc oxide is substituted for the paper pulp of the other battery4 ,it has been very little used4 ,battery1 ,volta's4 ,the original acid battery4 ,it has a negative electrode of copper1 a positive electrode of zinc2 the excitant is sulphuric acid diluted with sixteen times its volume of water4 ,it rapidly polarizes1 and is very little used4 ,battery1 ,voltaic or ,galvanic4 ,an apparatus for converting chemical energy directly into electric energy4 ,this is as broad a definition as can well be given4 ,the general conception of a battery includes the action of electrolysis1 a solution in the battery acting upon one of two conducting electrodes immersed in such fluid1 which dissolves one of them only1 or one more than the other4 ,the best way to obtain a fundamental idea of a battery is to start with the simplest4 ,dilute sulphuric acid dissolves neither pure zinc nor copper4 ,but it has a far stronger affinity for the first named metal4 ,if now we immerse in dilute acid two plates1 one of pure zinc1 and one of copper1 no action will be discernible4 ,but if the plates are brought in contact with each other a stream of bubbles of hydrogen gas will escape from the surface of the copper and the zinc will dissolve4 ,by applying proper tests and deductions it will be found that the copper and zinc are being constantly charged with opposite electricities1 and that these are constantly recombining4 ,this recombination produces what is known as an electric current4 ,to constitute a battery the zinc and copper plates must be connected outside of the solution4 ,this connection need not be immediate4 ,any conductor which touches both plates will bring about the action1 and the current will pass through it4 ,the easiest way to picture the action of a battery is to accept the doctrine of contact action4 ,in the battery the molecules of water are pulled apart4 ,the hydrogen molecules go to the copper1 the oxygen molecules go to the zinc1 each one1 leaving its contact with the other1 comes off charged with opposite electricity4 ,this charges the plates1 and the continuous supply of charge and its continuous discharge establishes the current4 ,the accumulation of hydrogen acts to stop the action by polarization4 ,its own affinity for oxygen acts against or in opposition to the affinity of the zinc for the same element1 and so cuts down the action4 ,a depolarizer of some kind is used in acid batteries for this reason4 ,as such depolarizer has only to act upon one plate1 in most batteries it is usual to surround such plate only1 as far as it is possible1 with the depolarizer4 ,the solution which dissolves the zinc is termed the excitant or exciting solution4 ,to this concrete notion of a voltaic battery the different modifications described here may be referred4 ,zinc1 it will be seen1 forms the almost universally used dissolved plate2 carbon or copper forms the most usual undissolved plate2 sulphuric acid in one form or another is the most usual excitant4 ,the solution in a voltaic battery is electrolyzed 7see ,electrolysis74 ,hence the solutions must be electrolytes4 ,the sulphuric acid and other ingredients play a secondary role as imparting to the battery fluids this characteristic4 ,it is not necessary to have electrodes of different substances1 the same metal maybe used for both if they are immersed in different solutions which act differentially upon them1 or which act with more energy on one than on the other4 ,such are only of theoretical interest4 #gg ,,standard ,,electrical ,,dictionary4 ,battery1 ,water4 ,a voltaic battery1 whose exciting fluid is water4 ,they are used for charging quadrant electrometer needles and similar purposes4 ,they polarize very quickly and are of high resistance4 ,hence very small plates in large number can be used without impairing their advantage4 ,rowland's water battery dispenses with cups and uses capillarity instead4 ,the zinc and platinum or copper plates of a couple are placed very close together1 while the couples are more distant4 ,on dipping into water each couple picks up and retains by capillarity a little water between its plates1 which forms the exciting fluid4 ,many hundred couples can be mounted on a board1 and the whole is charged by dipping into water and at once removing therefrom4 ,it then develops its full potential difference4 ,fig4 #ee4 ,,section ,,of ,,wollaston ,,battery4 ,fig4 #ef4 ,,plates ,,of ,,wollaston',s ,,battery4 #gh ,,standard ,,electrical ,,dictionary4 ,battery1 ,wollaston4 ,the original plunge battery is attributed to ,wollaston4 ,he also invented the battery known by his name1 having the disposition shown in the cut1 of zinc ,z1 surrounded by a thin sheet of copper ,c2 o1 o'1 o1 are the terminals and ,b1 ,b1 the battery jars4 ,dilute sulphuric acid is used for exciting fluid4 ,b4 ,a4 ,u4 ,abbreviation for ,british ,association unit1 referring generally to the ,b4 ,a4 unit of resistance4 ,b4 ,a4 ,unit of ,resistance4 ,the original ohm used under that name previous to #ahhd4 ,the ,paris committee of that year recommended as a practical unit what is known as the legal ohm4 7,see ,ohm1 ,legal47 #a ,legal ,ohm #a4jaab ,b4 ,a4 ,units of ,resistance4 #a ,b4 ,a4 ,unit of ,resistance 4#ihhi ,legal ,ohms4 #a ,b4 ,a4 ,unit of ,resistance 4#ihfea;,e#i ,c4 ,g4 ,s4 units4 ,b4 ,e4 adj4 ,british ,engineering1 a qualification of a set of units1 the ,b4 ,e4 units1 having for base the foot and pound4 ,the term is but little used4 ,beaum ,hydrometer4 ,a hydrometer graduated on the following principle3 ,the zero point corresponds to the specific gravity of water for liquids heavier than water4 ,a solution of #ae parts of salt in #he parts of water corresponds in specific gravity to #ae ,b41 and between that and zero fifteen equal degrees are laid out4 ,the degrees are carried down below this point4 ,the zero points for liquids lighter than water correspond to the specific gravity of a solution of #aj parts of salt in #ij parts of water4 ,the specific gravity of water is taken as #aj ,b4 ,this gives ten degrees which are continued up the scale4 ,becquerel's ,laws of ,thermoelectricity4 ,these are stated under the heads1 ,law of ,intermediate ,metals and ,law of ,successive ,temperatures1 q4 v4 ,bed ,piece4 ,in a dynamo or motor the frame carrying it1 including often the standards in which the armature shaft is journaled1 and often the yoke or even entire field magnet core4 ,bell1 ,automatic ,electric4 ,a bell which rings as long as the circuit is closed1 having a circuit breaker operated by its own motion4 7,see ,bell1 ,electric47 ,synonyms--,trembling ,bell--,vibrating ,bell4 ,bell1 ,call4 ,a bell operated by electricity1 designed to call attention1 as to a telephone or telegraphic receiver4 7,see ,bell1 ,electric47 #gi ,,standard ,,electrical ,,dictionary4 ,bell ,call4 ,a calling device for attracting the attention of any one1 consisting of some type of electric bell4 ,bell1 ,circular4 ,a gong-shaped bell1 whose clapper and general mechanism is within its cavity or behind it4 ,bell1 ,differentially ,wound4 ,an electric bell1 whose magnet is wound differentially so as to prevent sparking4 ,fig #eg4 ,,automatic ,,electric ,,bell4 ,bell1 ,electric4 ,a bell rung by electricity4 ,generally it is worked by a current exciting an electro-magnet1 attracting or releasing an armature which is attached to the vibrating or pivoted tongue of the bell4 ,it may be worked by a distant switch or press-button1 q4 v41 ringing once for each movement of the distant switch1 etc41 or it may be of the vibrating bell type as shown in the cut4 ,when the current is turned on in this case it attracts the armature4 ,as this moves towards the poles of the magnet it breaks the circuit by drawing the contact spring1 q4 v41 away from the contact point1 q4 v4 ,this opens the circuit1 to whose continuity the contact of these two parts is essential4 ,the hammer1 however1 by its momentum strikes the bell and at once springs back4 ,this again makes the contact and the hammer is reattracted4 ,this action continues as long as the circuit is closed at any distant point to which it may be carried4 ,the ordinary vibrating bell is a typical automatic circuit breaker1 q4 v41 this type keeping up the ringing as long as the circuit is closed4 ,other bells have no electric contact and simply ring once every time the circuit is closed4 ,others worked by an alternating current ring once for each change of direction of current4 #hj ,,standard ,,electrical ,,dictionary4 ,bell1 ,electro-mechanical4 ,a bell which has its striking train operated by a spring or descending weight1 and which train is thrown into action by the release of a detent or equivalent action by the closing of an electric circuit4 ,it rings for any given time after being started4 ,bell1 ,indicating4 ,a bell which by drop-shutter or other indicator connected in circuit with it1 indicates its number or other designation of its call4 ,bell1 ,magneto4 ,an electric bell operated by the alternating current from a magneto generator4 ,it has a polarized armature and no circuit breaker4 ,the armature is attracted first in one direction and then in the other1 as the current alternates and reverses the polarity of the electro-magnet4 ,bell1 ,relay4 ,a bell operated by a relay circuit4 ,bias4 ,in polarized relay the adjustment of the tongue to lie normally against one or the other contact4 7,see ,relay1 ,polarized47 #ha ,,standard ,,electrical ,,dictionary4 ,fig4 #eh4 ,,resistance ,,coils ,,showing ,,bifilar ,,winding4 ,bifilar ,winding4 ,the method followed in winding resistance coils to prevent them from creating fields of force4 ,the wire is doubled1 and the doubled wire starting with the bend or bight is wound into a coil4 ,the current going in opposite senses in the two lays of the winding produces no field of force4 ,binary ,compound4 ,a chemical compound whose molecule contains only two elements1 such as water 7,h#b #j71 lead oxide 7,pb #j71 and many others4 ,binding4 ,in a dynamo or motor armature the wire wound around the coils to secure them in place and prevent their disturbance by centrifugal action4 ,fig4 #ei4 ,,double ,,binding ,,post4 ,fig4 #fj4 ,,binding ,,post1 ,,english ,,pattern4 ,,fig4 #fa4 ,,wood ,,screw ,,binding ,,post4 ,binding ,posts or ,screws4 ,arrangements for receiving the loose end of a wire of an electric circuit1 and securing such end by a screw4 ,several constructions are used1 as shown here4 ,sometimes the wire is passed through a hole1 and a screw tapped in at right angles to the hole is screwed down upon the wire4 ,sometimes the wire is clamped between two shoulders1 one on the screw1 the other on the post4 ,the screw is often a flat-headed thumb screw or has a milled edge4 ,sometimes the screw has a slot and is turned by a screw-driver4 ,several openings are often provided in the same post for different wires4 ,binnacle4 ,the case containing a mariner's compass on shipboard4 ,it is enclosed completely2 it has a glass side or window through which the compass can be seen1 and is provided with one or two lamps arranged to light the card1 while showing as little light as possible outside4 #hb ,,standard ,,electrical ,,dictionary4 ,bioscopy1 ,electric4 ,the diagnosis of life and death by the action of the animal system when subjected to an electric current or electrification4 ,bismuth4 ,a metal1 one of the elements1 atomic weight1 #baj 2 equivalent1 #gj2 valency1 #c2 specific gravity1 #i4i4 ,it is a conductor of electricity4 ,relative ,resistance1 compressed1 7silver #a7 #hg4bc ,specific ,resistance1 #aca4b microhms ,resistance of a wire 7a7 #a foot long1 weighing #a grain1 #ah4dd ohms 7b7 #a foot long1 #a_/ajjj inch thick1 #ghi4c 7c7 #a meter long1 weighing #a gram1 #ab4hh 7d7 #a meter long1 #a millimeter thick1 #a4fgj ,resistance of a #a-;inch cube #ea4fe microhms ,electro chemical equivalent1 4#gcej 7,hydrogen 4#jaje7 7,see ,thermo-electric ,series47 ,,figs4 #fb1 #fc4 ,,incandescent ,,wire ,,fuse4 ,,abel',s ,,patent4 ,,fig #fd4 ,,von ,,ebner',s ,,frictional ,,electric ,,machine ,,for ,,exploding ,,electric ,,fuses ,,or ,,detonators4 ,bi-telephone4 ,a pair of telephones arranged with a curved connecting arm or spring1 so that they can be simultaneously applied to both ears4 ,they are self-retaining1 staying in position without the use of the hands4 #hc ,,standard ,,electrical ,,dictionary4 ,blasting1 ,electric4 ,the ignition of blasting charges of powder or high explosives by the electric spark1 or by the ignition to incandescence 7red or white heat7 of a thin wire immersed in or surrounded by powder4 ,special influence or frictional electric machines or induction coils are used to produce sparks1 if that method of ignition is employed4 ,for the incandescent wire a hand magneto is very generally employed4 7,see ,fuse1 ,electric47 ,the cuts1 ,figs4 #fb and #fc1 show one form of incandescent wire fuse4 ,the large wires are secured to the capsule1 so that no strand can come upon the small wire within the cavity4 ,the cut1 ,fig4 #fd1 shows a frictional electric machine for igniting spark fuses4 ,bleaching1 ,electric4 ,bleaching by agents produced or made available by the direct action of electricity4 ,thus if a current under proper conditions is sent through a solution of common salt 7sodium chloride71 the electrodes being close together1 the salt is decomposed1 chlorine going to one pole and sodium hydrate to the other4 ,the two substances react upon each other and combine1 forming sodium hypochlorite1 which bleaches the tissue immersed in its solution4 ,block ,system4 ,a system of signalling on railroads4 ,the essence of the system consists in having signal posts or stations all along the road at distances depending on the traffic4 ,the space between each two signal posts is termed a block4 ,from the signal posts the trains in day time are signalled by wooden arms termed semaphores1 and at night by lanterns4 ,the arms may be moved by hand or by automatic mechanism depending in part on electricity for carrying out its functions4 ,thus in the ,westinghouse system the semaphores are moved by pneumatic cylinders and pistons1 whose air valves are opened and shut by the action of solenoid magnets1 q4 v4 ,the current of these magnets is short circuited by passing trains1 so as to let the valves close as the train passes the signal post4 ,the block system causes the semaphore to be set at danger or caution1 as the train enters the next block4 ,then the following train is not allowed to enter the block until the safety signal is shown4 ,the ,westinghouse system provides for two semaphores on a post1 one indicating danger as long as the train is on the next block2 the other indicating caution as long as the train is on the next two blocks4 ,the rails form part of the circuit1 their joints being bridged by copper wire throughout the block1 and being insulated where the blocks meet4 ,block ,wire4 ,in the block system a wire connecting adjacent block-signal towers or semaphore poles4 ,blow-pipe4 ,a name sometimes given to an electric experiment illustrating the repulsion of electrified air particles from a point held at high relative potential4 ,a metallic point1 placed on the prime conductor of an electric friction or influence machine1 becomes highly electrified1 and the air becoming excited is repelled and acts upon the candle flame4 ,if the candle is placed on the conductor and a point held towards it the repulsion is still away from the point4 #hd ,,standard ,,electrical ,,dictionary4 ,blow-pipe1 ,electric ,arc4 ,a name sometimes given to devices for using the voltaic arc to produce local heating effects4 ,the directive action of the magnet may be used to force out the arc like a blow-pipe flame1 or a blast of air may be directly applied for the same purpose4 ,blue-stone4 ,a trade name for crystallized copper sulphate1 used in ,daniell's and gravity batteries4 ,boat1 ,electric4 ,a boat propelled by electricity4 ,the electricity drives a motor which actuates a screw propeller4 ,the current is generally supplied by a storage battery4 ,when used on rivers charging stations are established at proper places4 ,when the boat is used as a tender or launch for a steam ship1 such as a war-vessel1 the battery is charged by a plant on board the ship4 ,from their noiselessness electric boats are peculiarly available for nocturnal torpedo operations1 and the universal equipment of modern war-ships with electric lightning and power plants makes their use possible at all points4 ,this type is often termed an electric launch1 and most or all electric boats fall under this category4 ,bobbins4 ,a spool of wood or other material wound with insulated wire4 ,in a tangent galvanometer the bobbin becomes a ring1 with a channel to receive the winding4 ,as the ring is not infinitely large compared to the needle the tangent law is not absolutely fulfilled4 ,it is most accurately fulfilled 7,s4 ,p4 ,thomson7 when the depth of the groove or channel in the radial direction bears to the breadth in the axial direction the ratio of square root of #c to the square root of #b or approximately #aa 3 #i ,body ,protector4 ,a metallic short circuit connected with the wrists and lower legs of the human body1 so that if by accident an active circuit is grounded by the hands and body of the workman wearing it1 most of the current will pass through the wire conductors1 thus avoiding the vital organs of the body4 ,boiler ,feed1 ,electric4 ,an apparatus by which an electric current acting on an electro-magnet1 or other equivalent device1 opens the water supply when the water level in a boiler sinks too low1 and cuts off the water supply as the water level rises4 ,boiling4 ,in secondary batteries the escape of hydrogen and oxygen gas when the battery is charged4 ,the bubbling of the escaping gases produces the effect of boiling4 #he ,,standard ,,electrical ,,dictionary4 ,boll4 ,an absolute1 or c4 g4 s41 unit of momentum2 a gram moving at the rate of one centimeter per second2 a gram-kine 7see ,kine72 a unit proposed by the ,british ,association4 ,bolometer4 ,an apparatus for detecting small amounts of radiant energy 7radiant heat1 so called74 ,a coil suspended by a fine wire or filament so as to be free to rotate under the effect of force is made up of two parallel and equal wires1 insulated from each other1 but connected so that parallel currents sent through them go in opposite direction through each4 ,this coil is hung in a strong electro-magnetic field produced by a large coil surrounding it4 ,when a current passes through the suspended coil no effect will follow1 because the oppositely wound portions counteract each other exactly4 ,in the circuit with one half of the suspended coil is an exceedingly thin strip of platinum wire4 ,the other half of the coil has no strips4 ,both halves unite after leaving the coil4 ,if now the strip of platinum is heated its conductivity is affected and its half of the coil receives less current than the other half4 ,this disturbs the balance and the coil swings through a small arc4 ,this apparatus may be made very sensitive1 so that an increase of temperature of #a_/adjj ,f41 #i_/gjjjj;,c4 7#a_/adjjj ,f47 will be perceptible4 ,another construction takes the form of a ,wheatstone ,bridge1 q4 v41 in whose arms are introduced resistances consisting of bands of iron1 4#e ,millimeter wide 74#jb inches71 4#jjd millimeter 74#jjjaf inch7 thick1 and folded on themselves #ad times so as to make a rectangular grating1 #ag x #ab millimeters 74#fh x 4#dh inch74 ,the least difference of heat applied to the grating affects the galvanometer4 ,synonym-,thermic ,balance4 ,boreal ,pole4 ,the south pointing pole of the magnet4 7,see ,austral ,pole47 ,bot4 ,a colloquial expression for the ,english ,board of ,trade unit of ,electrical ,supply4 ,it is formed of the initials of the words ,board of ,trade4 7,see ,unit1 ,board of ,trade47 ,box ,bridge4 ,a constriction of ,wheatstone's ,bridge in which the necessary resistance coils are contained in a single box with plugs for throwing the coils in and out of circuit1 and connections to bring the coils into the different arms of the system4 ,the cut shows a box bridge4 ,connections for the galvanometer1 battery wires1 and terminals of the unknown resistance are provided1 by which its resistances and the connections are brought into the exact relations indicated in the conventional diagram of ,wheatstone's bridge4 7,see ,wheatstone's ,bridge47 ,referring to the cut1 the battery wire1 say from the zinc plate1 connects at ,a#a1 thereby reaching ,a1 its true connecting point4 ,to ,b#a one end of the galvanometer circuit or lead is attached1 thereby reaching ,b1 its true connecting point4 ,to ,c are connected the other end from the galvanometer and one end of the unknown resistance4 ,the other end of the unknown resistance1 and the other end of the battery wire1 in this case from the carbon plate1 connect to ,d4 ,at ,g is an infinity plug1 as it is called4 ,when out it breaks the circuit4 ,in use after the connections are made the key is depressed and the galvanometer observed4 ,the resistance is changed until no action of the galvanometer is produced by closing the circuit when the ratio of the resistances of the arms gives the proportion for calculating the unknown resistances4 ,synonym--,commercial ,wheatstone ,bridge1 or commercial form of same4 ,fig4 #fe4 ,,top ,,of ,,box ,,bridge4 #hf ,,standard ,,electrical ,,dictionary4 ,boxing the ,compass4 ,naming the thirty-two points of the compass in order1 and in sequence to any point called out at random4 ,there are many exercises in the relative sailing points and bearings that come under the same head4 ,thus the direction of two given points being given by names of the compass points1 it may be required to state the number of points intervening4 ,brake1 ,electro-magnetic4 ,a brake to stop a wheel from rotating4 ,it comprises a shoe1 or sometimes a ring1 which by electro-magnetic attraction is drawn against the rotating wheel1 thus preventing it from turning1 or tending to bring it to rest4 7,see ,electro-magnet1 ,annular47 ,fig4 #ff4 ,,electric ,,brake4 #hg ,,standard ,,electrical ,,dictionary4 ,branch4 ,a conductor branching from a main line4 ,sometimes the term is restricted to a principal conductor1 from which current is distributed4 ,branch ,block4 ,in electric wiring of buildings1 a block of porcelain or other material with grooves1 holes and screws for the connection of branch wires to a main wire4 ,its functions are not only to afford a basis for connecting the wires1 but also to contain safety fuses4 ,as when a branch wire is taken off1 fuses have to be put in its line1 the branch block carries these also4 ,one end of each fuse connects with a main wire1 the other end connects with one of the wires of the branch leader or wire4 ,porcelain is a favorite material for them1 as the fusing or blowing out of the safety fuses cannot set it on fire4 ,branch ,conductor4 ,a parallel or shunt conductor4 ,brazing1 ,electric4 ,brazing in which the spelter is melted by means of electricity2 either current incandescence or the voltaic arc may be used4 ,it is identical in general with electric welding4 7,see ,welding1 ,electric47 ,branding1 ,electric4 ,a system of branding in which the heat of electrically ignited or incandescent conductors is used to produce or burn in the marks upon the surface4 ,for the alternating current a small transformer is connected to or forms part of the tool4 #hh ,,standard ,,electrical ,,dictionary4 ,brassing4 ,the deposition of a coating of brass by electrolysis4 ,the plating bath contains both copper and zinc4 ,as anode a plate of brass is used4 ,the operation must be constantly watched4 ,the deposition of both metals goes on simultaneously1 so that a virtual alloy is deposited4 ,by changing the depth of immersion of the anode the color of the deposit is varied4 ,as a formula for a brassing bath the following are typical4 ,they are expressed in parts by weight4 7a7 ,for iron and steel4 ,i4 ,sodium ,bisulphate1 #bjj ,potassium ,cyanide1 #gj per cent41 #ejj ,sodium ,carbonate1 #a1jjj ,water1 #h1jjj ,,ii4 ,copper ,acetate1 #abe ,zinc ,chloride1 #ajj ,water1 #b1jjj ,add the second solution to the first4 7b7 ,for zinc4 ,i4 ,sodium ,bisulphate1 #gjj ,potassium ,cyanide1 #gj per cent41 #a1jjj ,water1 #bj1jjj ,,ii4 ,copper ,acetate1 #cej ,zinc ,chloride1 #cej ,aqua ,ammoniae1 #djj ,water1 #e1jjj ,add the second solution to the first4 ,use a brass anode2 add more zinc to produce a greenish color2 more copper for a red color4 ,a weak current gives a red color2 a strong current lightens the color4 ,the battery power can be altered1 a larger or smaller anode can be used1 or a copper or zinc anode can be used to change the color of the deposit4 ,the bath may vary from #a4jcf to #a4ajj sp4 gr41 without harm4 ,break4 ,a point where an electric conductor is cut1 broken1 or opened by a switch or other device1 or simply by discontinuity of the wires4 ,break-down ,switch4 ,a switch used in the three-wire system to provide for the discontinuance of the running of one of the dynamos4 ,by connecting the positive and negative bus wires to one terminal of the active dynamo1 and the neutral bus wire to the other terminal1 one dynamo will supply the current and the system operates like a two-wire system1 but can only be used for half its normal capacity4 ,breaking ,weight4 ,the weight which1 applied in tension1 will break a prism or cylinder1 as an electric current conductor4 #hi ,,standard ,,electrical ,,dictionary4 ,breath ,figures1 ,electric4 ,if a conductor is electrified and placed upon a piece of glass1 it will electrify the glass in contact with it by conduction or discharge4 ,on removing the conductor the glass remains electrified4 ,the localized electrification is shown by breathing gently on the glass1 when a species of image of the conductor is produced by the condensed moisture4 ,a coin is often used for conductor4 ,breeze1 ,electric4 ,a term in medical electricity1 used to designate the silent or brush discharge of high tension electricity4 ,as an instance of its employment1 the electric head bath 7see ,bath1 ,electric ,head17 may be cited4 ,the patient forming one electrode1 being insulated and connected to one of the conductors1 the other conductor1 on being brought near his person1 discharges into his body4 ,bridge4 7a7 ,a special bar of copper connecting the dynamos to the bus wire1 q4 v41 in electric lighting or power stations4 7b7 ,wheatstone's bridge1 q4 v41 and its many modifications1 all of which may be consulted throughout these pages4 ,british ,association ,bridge4 ,the type of ,wheatstone bridge used by the committee of the association in determining the ,b4 ,a4 ohm2 the meter bridge1 q4 v4 ,broadside ,method4 ,a method of determining the magnetic moment of a magnet4 ,the magnet1 n1 s1 under examination is fixed so that it is at right angles to the magnetic meridian1 ,m1 ,r1 which passes through its own center and that of a compass needle4 ,from the deflection of the latter the moment is calculated4 ,,fig #fg4 ,,broadside ,,method4 ,bronzing4 ,in electro-plating the deposition of a mixture or virtual alloy of copper and tin4 ,in general manipulation it resembles the operation of depositing gold and silver alloy1 or of brassing4 ,for bronzing the following bath is recommended3 ,prepare each by itself 7a7 a solution of copper phosphate and 7b7 a solution of stannous chloride in a solution of sodium pyrophosphate4 ,for a1 dissolve recently precipitated copper phosphate in concentrated solution of sodium pyrophosphate4 ,for b1 add to a saturated solution of sodium pyrophosphate solution of stannous chloride as long as the precipitate which is formed dissolves4 ,of these two solutions add to a solution of sodium pyrophosphate which contains about #a4ge oz4 of the salt to the quart1 until the precipitate appears quickly and of the desired color4 ,for anodes use cast bronze plates4 ,sodium phosphate must be added from time to time2 if the deposit is too light add copper solution1 if too dark add tin solution4 7,w4 ,t4 ,brannt47 #ij ,,standard ,,electrical ,,dictionary4 ,brush4 ,in electric current generators and motors1 the pieces of copper or other material that bear against the cylindrical surface of the commutator are thus termed4 ,many different constructions have been employed4 ,some have employed little wheels or discs bearing against and rotating on the surface of the commutator4 ,a bundle of copper strips is often employed1 placed flatwise4 ,sometimes the same are used1 but are placed edgewise4 ,wire in bundles1 soldered together at their distant ends have been employed4 ,carbon brushes1 which are simply rods or slabs of carbon1 are used with much success4 ,synonym--,collecting ,brush4 ,brush1 ,carbon4 ,a brush for a dynamo or motor1 which consists of a plate or rod of carbon1 held in a brush holder and pressed against the commutator surface4 ,brushes1 ,adjustment of4 ,in electric current generators and motors1 the brushes which bear upon the commutator when the machine is in action need occasional adjustment4 ,this is effected by shifting them until sparking between them and the commutator is nearly or quite suppressed4 ,fig4 #fh4 ,,brush ,,holder4 ,brushes1 ,lead of4 ,in a dynamo electric generator1 the lead or displacement in advance of or beyond the position at right angles to the line connecting the poles of the field magnet1 which is given the brushes4 ,in a motor the brushes are set back of the right angle position1 or are given a negative lead4 7,see ,lag47 #ia ,,standard ,,electrical ,,dictionary4 ,brush ,holders4 ,the adjustable 7generally7 clutch or clamps for holding the commutator brushes of a dynamo1 which keep them in contact with the commutator1 and admit of adjustment by shifting backward and forward of the brushes to compensate for wear4 ,they are connected to and form part of the rocker1 q4 v4 ,by rotating the latter the brush-holders and brushes are carried in one direction or other around the commutator1 so as to vary the lead as required4 ,brush1 ,pilot4 ,a third brush1 used for application to different parts of a revolving armature commutator to determine the distribution of potential difference between its different members4 7,see ,curve of ,distribution of ,potential in ,armature47 ,one terminal of a volt-meter is connected to one of the regular brushes1 ,a1 of a dynamo2 the other to a third brush1 p1 which is pressed against different portions of the commutator of the dynamo4 ,the readings of the volt-meter are plotted in a curve of distribution of potential4 ,fig4 #fi4 ,,pilot ,,brush4 ,brush1 ,rotating4 ,brushes for taking off the current from dynamo commutators1 or giving current connection to motors1 whose ends are in the form of rollers which rotate like little wheels1 and press against the commutator surface4 ,brush1 ,third4 ,a third brush is sometimes provided in a dynamo for regulating purposes4 ,applied to a series machine it adjoins one of the regular brushes and delivers its current to a resistance1 to whose further end the regular circuit is connected4 ,by a sliding connection the resistance is divided between the third brush circuit and the regular circuit1 and by varying the position of this contact regulation is obtained4 ,it is to be distinguished from the pilot brush used for determining the characteristic of the commutator1 although based on the same general principles4 ,fig4 #gj4 ,,third ,,brush ,,regulation4 #ib ,,standard ,,electrical ,,dictionary4 ,brush1 ,wire ,gauze4 ,a collecting or commutator brush for a dynamo or motor1 which brush is made of wire gauze rolled up and compressed into shape4 ,buckling4 ,the bending up and distortion of secondary battery plates4 ,it is largely due to over-exhausting the batteries4 ,where the ,e4 ,m4 ,f4 is never allowed to fall below #a4ij volt it is far less liable to occur4 ,bug4 ,any fault or trouble in the connections or working of electric apparatus4 ,bug ,trap4 ,a connection or arrangement for overcoming a bug4 ,it is said that the terms bug and bug trap originated in quadruplex telegraphy4 ,bunsen ,disc4 ,in photometry1 the ,bunsen ,disc is a piece of paper upon whose centre a spot is saturated with melted paraffin1 or a ring of paraffined surface surrounds an untouched central spot4 ,if placed in such a position that it receives an equal illumination on each side1 the spot almost disappears4 ,it is used on the bar photometer4 7,see ,photometer1 ,bar47 ,synonym--,grease ,spot4 #ic ,,standard ,,electrical ,,dictionary4 ,buoy1 ,electric4 ,a buoy for use to indicate channels or dangers in harbors and elsewhere1 which carries an electric light1 whose current is supplied by cable from shore4 ,it has been proposed to use glass tubes exhausted of air and containing mercury1 which1 as moved by the waves1 would produce a luminous effect4 ,a fifty-candle power incandescent lamp is an approved source of light4 ,burner1 ,electric ,gas4 ,a gas burner arranged for the flame to be lighted by electricity4 ,it takes a great variety of forms4 ,in some cases a pair of terminals are arranged near the flame or a single terminal is placed near the metal tip1 the latter forming one of the terminals4 ,the spark is generally produced by an induction coil1 or a spark coil4 ,the gas may first be turned on and the spark then passed4 ,sometimes the turning of the gas cock of an individual burner makes and breaks a contact as it turns1 and thereby produces simultaneously with the turning on of the gas a spark which lights it4 ,another form is wholly automatic4 ,a pair of electro-magnets are attached below the base of the burner1 one of which1 when excited1 turns on the gas1 and the other one when it is excited turns it off4 ,at the same time a spark is produced with the turning on of the gas so that it is lighted4 ,thus1 by use of a automatic burner1 a distant gas burner can be lighted by turning an electric switch4 ,an out-door lamp may be lighted from within a house4 ,the increasing use of electric incandescent lamps1 lighted by the turning of a switch1 tends to displace electric gas burners4 ,the latter have been classified into a number of types depending on their construction4 ,burners are sometimes connected in series with leads from an induction coil4 ,then the gas is turned on all at once1 and a succession of sparks passed until the gas is all lighted4 ,the ignition is practically instantaneous4 ,button1 ,push4 ,a species of switch which is actuated by the pressure of a button4 ,in its normal position the button is pressed outwards by a spring1 and the circuit is open4 ,when pressed inwards1 it closes the circuit4 ,when released it springs backward and opens the circuit again4 ,they are principally used for ringing bells4 ,if the latter are of the automatic type1 they ring as long as the button is pressed4 ,for door-bells and room-bells1 the button often occupies the center of a rosette of wood or bronze or other ornamental piece4 ,sometimes1 as shown in the cut1 they are constructed for use on floors to be pressed by the foot4 ,the general principle of their construction is shown1 although the method of making the contact varies4 ,synonym--,press ,button4 ,fig4 #ga4 ,,floor ,,push ,,button4 #id ,,standard ,,electrical ,,dictionary4 ,burning4 7a7 ,in a dynamo1 the production of shifting and temporary arcs between the commutator and brushes1 which arcs produce heat enough to injure the parts in question4 7b7 ,in electro-plating1 a defect due to too strong a current in proportion to the strength of solution and area of electrodes4 ,this gives a black or badly-colored deposit4 ,bus ,rod4 ,a copper conductor used in electric lighting or power stations1 to receive the current from all the dynamos4 ,the distributing leads are connected to the bus wires4 ,in the three-wire system there are three2 in the two-wire system there are two bus wires4 ,the name is undoubtedly derived from omnibus4 ,the bus wires may be divided into positive1 negative1 and1 in the three-wire system1 neutral bus wires4 ,synonyms--,omnibus ,rod1 ,wire1 or ,bar--,bus ,bar1 or ,wire4 ,buzzer4 ,an electric alarm or call produced by a rapid vibration of electric make and break mechanism1 which is often magnified by enclosure in a resonating chamber1 resembling a bell1 but which is not struck or touched by the vibrating parts4 ,sometimes a square wooden box is used as resonator4 ,fig4 #gb4 ,,buzzer4 #ie ,,standard ,,electrical ,,dictionary4 ,b4 ,w4 ,g4 ,abbreviation for ,birmingham ,wire ,gauge4 7,see ,wire ,gauge1 ,birmingham47 ,c4 7a7 ,abbreviation for ,centigrade1 as #ajj ,c41 meaning #ajj ,centigrade4 7,see ,centigrade ,scale47 7b7 ,a symbol of current or of current strength4 ,thus in the expression of ,ohm's law ,c ,e_/,r4 ,c indicates current strength or intensity1 not in any fixed unit1 but only in a unit of the same order in which ,e and ,r are expressed2 ,e ,indicating electro-motive force and ,r resistance4 ,cable4 7a7 ,abbreviation for ,cablegram1 q4 v4 7b7 v4 ,it is also used as a verb1 meaning to transmit a message by submarine cable4 7c74 ,an insulated electric conductor1 of large diameter4 ,it often is protected by armor or metallic sheathing and may be designed for use as an aerial1 submarine1 subterranean or conduit cable4 ,a cable often contains a large number of separately insulated conductors1 so as to supply a large number of circuits4 ,cable1 ,aerial4 ,a cable usually containing a large number of separately insulated wires1 and itself insulated4 ,it is suspended in the air4 ,as its weight is sometimes so great that it could not well sustain it1 a suspending wire is in such cases carried along with it1 to which it is suspended by cable hangers1 q4 v4 ,cable ,box4 ,a box for receiving underground cable ends and connecting the separate wires of the cable to air-line wires4 ,it is often mounted on a pole1 which forms the starting point of the air-line portion of the system4 ,cable1 ,bunched4 ,a cable containing a number of separate and individual conductors4 ,in some forms it consists virtually of two or more small cables laid tangent to each other and there secured4 ,thus each in section represents two or more tangent circles with the interstice solidly filled with the metal sheathing4 ,cable1 ,capacity of4 ,the electrostatic capacity of a cable4 ,a cable represents a ,leyden jar or static condenser4 ,the outer sheathing or armor1 or even the more or less moist coating1 if it is unarmored1 represents one coating4 ,the wire conductors represent the other coating1 and the insulator is the dielectric4 ,the capacity of a cable interferes with its efficiency as a conductor of broken or interrupted currents1 such as are used in telegraphy or telephoning4 ,as each impulse or momentary current is sent into the line1 it has to charge the cable to at least a certain extent before the effects of the current are perceptible at the other end4 ,then the cable has to discharge itself4 ,all this creates a drag or retardation4 ,the capacity of a cable is used to determine the locality of breaks in the continuity of the conductors4 ,the capacity per unit of length being accurately known1 it is obvious that1 if the conductor breaks without disturbance of the insulator1 the distance of the break from the end can be ascertained by determining the capacity of the cable from one end4 ,this capacity will be in proportion to the capacity of a mile1 a knot or any fixed unit1 as the distance to the break is to the length used as standard4 #if ,,standard ,,electrical ,,dictionary4 ,cable ,core4 ,the conductors of a cable4 ,they are generally copper wire4 ,in a telephone cable they may be very numerous and insulated from each other4 ,in ocean cables they may be a group of bare wires twisted or laid together4 ,sometimes the conductors are arranged for metallic circuits1 each pair being distinguished by special colored windings4 ,cable1 ,duplex4 ,a cable containing two wires1 each with separate insulation1 so as to be virtually two cables1 laid and secured parallel and side by side4 ,cable1 ,flat4 ,a cable1 flat in shape1 so as to lie closely against a wall or ceiling4 ,cablegram4 ,a message which has been transmitted or is to be transmitted by a submarine cable4 ,it is sometimes called a cable4 ,cable ,grip4 ,a grip for holding the end of a cable1 when the cable is to be drawn into a conduit in a subway4 ,it is an attachment to provide the cable with an eye or loop4 ,its end is a split socket and embraces the end of the cable1 and is secured thereto by bolts driven through the cable end4 ,in drawing a cable into a conduit a capstan and rope are often used1 and the rope is secured to the cable end by the grip4 ,fig4 #gc4 ,,cable ,,hanger1 ,,cable1 ,,and ,,suspending ,,wire4 ,fig4 #gd4 ,,cable ,,hanger1 ,,open4 ,cable ,hanger4 ,when a heavy electric cable is suspended from poles it often would be unsafe to trust to its longitudinal strength to support or sustain its own weight unless the poles were very near together4 ,in such case an auxiliary or sustaining wire is run along with it1 and by clips or hangers the cable is connected thereto at as frequent intervals as seem desirable4 ,the contrivance may take the form of a strip of metal surrounding the cable and carrying a hook or eye through which the supporting wire passes4 ,synonym--,cable ,clip4 #ig ,,standard ,,electrical ,,dictionary ,cable ,hanger ,tongs4 ,tongs for attaching cable hangers1 q4v4 ,they have long handles so as to be worked from the ground at the middle of a span4 ,cable1 ,suspending ,wire of4 ,a wire by which an aerial cable is in part or entirely suspended4 ,the cable1 being incapable of sustaining its own weight1 is secured by clips or hangers to a wire1 strong from pole to pole immediately above it4 7,see ,cable ,hanger47 ,cable ,tank4 ,a tank in which a submarine cable is coiled away on board a cable-laying ship1 or in the factory on shore for the purpose of testing or watching its insulation4 ,sometimes1 in order to test it under pressures approximating to those it will be subjected to in practice1 the tank is closed and the portion of cable within it is subjected to hydraulic pressure4 ,this represents the pressure it will be exposed to in deep water4 ,calamine4 ,a mineral2 zinc silicate2 formula ,zn#b ,si #jc1 crystalline system1 ,orthorhombic2 specific gravity1 #c4af-c4i4 ,the crystals often show strong pyroelectric properties4 ,calibration4 ,the determination by experiment or calculation of the value of the readings of an instrument1 such as a galvanometer or eudiometer4 ,thus if a tangent galvanometer has its circle graduated in degrees1 a table of the value of tangents corresponding to every reading occurring in practice would represent a calibration by calculation4 ,a determination of the current required to produce each deflection would be a calibration in the more usual sense4 ,calibration is generally absolute1 as referring to some fixed unit1 but it may be relative1 as between two things both of unknown absolute value4 ,calibration1 ,absolute4 ,the determination of the absolute value of currents producing given deflections in a galvanometer1 or in other instruments the determination of corresponding values1 as the instrument may be a magnetometer1 quadrant electrometer1 or other apparatus4 ,calibration1 ,invariable4 ,calibration applicable to specially constructed galvanometers1 which is unaffected by the proximity of masses of iron or field magnets4 ,such galvanometers must have a constant controlling field4 ,such is given by a powerful permanent magnet1 whose field is practically unaffected by the causes named4 ,or else1 in place of a controlling field1 a spring maybe used to which the needle is attached1 and which tends to hold it in one position4 #ih ,,standard ,,electrical ,,dictionary4 ,calibration1 ,relative4 ,the determination of the law connecting the various indications of an instrument1 such as the deflections of the needle of a galvanometer1 with the relative causes2 in the case of a galvanometer1 the strength of the currents or the electro-motive forces producing them directly or indirectly4 ,call ,bell4 ,a bell rung by pressing a button or otherwise to call the attention of a person in a distant place4 ,they can be classified into a great variety of types according to their uses or construction4 ,call ,button4 ,a push button used for ringing a call bell1 sounding a buzzer1 working an annunciator and for similar purposes4 7,see ,push ,button47 ,synonym--,push ,button4 ,calling ,drop4 ,in a telephone exchange or telegraph office a drop shutter annunciator1 which falls to call the attention of the operator1 notifying him that the line connected to such drop is to be connected to some other circuit4 ,calorie or ,calory4 ,a practical unit of heat4 ,there are two calories1 respectively called the great and the small calorie1 or the kilogram and the gram calorie4 ,the first is the quantity of heat required to raise the temperature of one kilogram of water one degree centigrade4 ,the second is the quantity of heat required to raise the temperature of one gram of water one degree centigrade4 ,calorimeter4 ,an apparatus for measuring the quantity of heat evolved or produced by or under different conditions4 ,dulong's water calorimeter consists of a water jacket1 and by the increase of temperature of the water and enclosing vessels the amount of heat produced by anything in the inner vessels is determined4 ,the amount of ice a heated body will melt is sometimes made the basis of a calorimeter4 ,the expansion of a fluid1 as water1 may be used4 ,in the calorimeter shown in the cut the heat produced in a conductor by the passage of an electric current is caused to heat water whose temperature is shown by a thermometer immersed therein4 ,the increase of temperature and the weight of the water give the basis for a determination of the heat produced by the current4 ,knowing the resistance of the conductor immersed1 the watts can be calculated4 ,this gives the bases for the determination of the heat-equivalent of electric energy4 ,this is but an imperfect calorimeter1 as it constantly would lose heat by the surrounding atmosphere1 and would cease to operate as a calorimeter when the water was as hot as the wire normally would be1 for then it would not absorb all the heat4 ,fig4 #ge4 ,,calorimeter4 #ii ,,standard ,,electrical ,,dictionary4 ,candle4 ,the generally accepted unit of illuminating power2 there are three kinds in use as standards4 7,see ,candle1 ,decimal--,candle1 ,german ,standard--,candle1 ,standard47 ,candle1 ,concentric4 ,an electric candle of the ,jablochkoff type1 having a small solid carbon inside of an outside tubular carbon1 the space between being filled with refractory material corresponding to the colombin1 q4 v41 of the ordinary type4 ,the arc springs across from one carbon to the other4 ,candle1 ,debrun4 ,an arc lamp with approximately parallel carbons4 ,a transverse priming connects their bases1 and the arc starting there at once flies out to the end4 ,candle1 ,decimal4 ,a standard of illuminating power1 proposed to the ,congress of ,electricians of #ahhi by ,picou4 ,it is one-twentieth of a ,viole1 or almost exactly one standard candle4 7,see ,viole's ,standard of ,illuminating ,power47 ,candle1 ,electric4 ,an arc lamp regulated by simple gravity1 or without any feed of the carbons or special feeding apparatus1 generally for the production of an arc light of low intensity4 ,this definition may be considered too elastic1 and the word may be restricted to parallel carbon lamps in which the arc springs across from carbon to carbon4 ,for the latter class an alternating current is used to keep the carbons of equal length4 ,they are but little used now4 ,various kinds have been invented1 some of which are given here4 ,candle1 ,german ,standard4 ,a standard of illuminating power used in ,germany4 ,it is a paraffin candle1 #f to the pound1 #bj millimeters diameter2 flame1 #ef millimeters high2 rate of consumption1 #g4g grams per hour4 ,its value is about two per cent4 lower than the ,english standard candle4 #ajj ,,standard ,,electrical ,,dictionary4 ,candle ,holder4 ,a clamp for holding electric candles of the ,jablochkoff type4 ,the ones shown in the cut designed for ,jablochkoff candles comprise a pair of metallic clamps1 each member insulated from the other1 and connected as terminals of the circuit4 ,when the candle is placed in position the metal pieces press against the carbons of the candle and thus convey the current4 ,below each member of the clamps is a binding screw for the line wire terminals4 ,fig4 #gf4 ,,jablochkoff ,,candle ,,holders4 ,fig4 #gg4 ,,jablochkoff ,,candle4 ,candle1 ,jablochkoff4 ,an arc lamp without regulating mechanism1 producing an arc between the ends of parallel carbons4 ,it consists of two parallel rods of carbon1 between which is an insulating layer of non-combustible material called the colombin4 ,kaolin was originally employed for this part2 later1 as the fusion of this material was found to short- circuit the arc1 a mixture of two parts of calcium sulphate and one of barium sulphate was used4 ,the carbons are #d millimeters 74#af inch7 thick1 and the colombin is #c millimeters 74#ab inch7 wide and two-thirds as thick4 ,a little slip of carbon is placed across the top1 touching both carbons to start the arc4 ,once started the candle burns to the end1 and cannot be restarted after ignition1 except by placing a short conductor across the ends1 as at first4 ,the ,jablochkoff candle may now be considered as virtually extinct in this country4 ,in ,france at one time a great number were in use4 ,to keep the carbons of equal length an alternating current must always be used with them4 ,special alternating combinations were employed in some cases where a direct current had to be drawn upon4 ,candle1 ,jamin4 ,an arc lamp with approximately parallel carbons1 one of which oscillates and is controlled by an electro-magnet and armature4 ,a coil of wire is carried around the carbons to keep the arc steady and in place4 ,the frame and wire coils have been found unsatisfactory1 as causing a shadow4 ,candle ,power4 ,the amount of light given by the standard candle4 ,the legal ,english and standard ,american candle is a sperm candle burning two grains a minute4 ,it should have burned some ten minutes before use1 and the wick should be bent over and have a red tip4 ,otherwise its readings or indications are useless4 ,a sixteen candle power lamp means a lamp giving the light of sixteen candles4 ,the candle power is a universal unit of illuminating power4 #aja ,,standard ,,electrical ,,dictionary4 ,candle ,power1 ,rated4 ,the candle power of arc lamps is always stated in excess of the truth1 and this may be termed as above4 ,a #bjjj candle power lamp really gives about #hjj candles illumination4 ,synonym--,nominal ,candle ,power4 ,candle ,power1 ,spherical4 ,the average candle power of a source of light in all directions4 ,an arc lamp and an incandescent lamp vary greatly in the intensity of light emitted by them in different directions4 ,the average of a number of determinations at various angles1 the lamp being moved about into different positions1 is taken for the spherical candle power4 ,candle1 ,standard4 ,a standard of illuminating power4 ,unless otherwise expressed the ,english standard sperm candle is indicated by this term4 7,see ,candle ,power47 ,candle1 ,wilde4 ,an arc lamp with approximately parallel carbons4 ,one of the carbons can rotate through a small arc being pivoted at its base4 ,this oscillation is regulated by an electro-magnet at its base1 and the carbons touch when no current is passing4 ,they separate a little when the current passes1 establishing an arc4 ,the regulation is comparable to that of a regular arc lamp4 ,fig4 #gh4 ,,wilde ,,candle4 ,caoutchouc4 ,india rubber2 a substance existing in an emulsion or solution in the juice of certain trees and vines of the tropics1 whence it is obtained by coagulation and drying4 ,the name rubber is due to the fact that one of its earliest uses was for erasing pencil marks by rubbing4 ,it has a very high value as an insulator4 ,the unworked crude rubber is called virgin gum2 after working over by kneading1 it is termed masticated or pure gum rubber2 after mixture with sulphur and heating1 it is termed vulcanized rubber4 ,if enough sulphur is added it becomes hard1 and if black1 is termed ebonite2 if vermilion or other pigment is also added to produce a reddish color1 it is termed vulcanite4 ,the masticated gum dissolves more or less completely in naphtha 7sp4 gr41 4#hej7 benzole1 turpentine1 chloroform1 ether and other similar liquids44 ,the resistance per centimeter cube of ,hooper's vulcanized ,india rubber1 such as is used in submarine cables is #a4e;,e#af ohms4 ,the specific inductive capacity of pure ,india rubber is #b4cd--of vulcanized #b4id 7,schiller74 ,synonyms--,india ,rubber--,rubber4 #ajb ,,standard ,,electrical ,,dictionary4 ,capacity1 ,dielectric4 ,the capacity of a dielectric in retaining an electrostatic charge2 the same as ,specific ,inductive ,capacity4 ',the number expressing it is sometimes called the dielectric constant4 7,see ,capacity1 ,specific ,inductive47 ,capacity1 ,electric1 or ,electrostatic4 ,the relative capacity of a conductor or system to retain a charge of electricity with the production of a given difference of potential4 ,the greater the charge for a given change of potential1 or the less the change of potential for a given charge the greater the capacity4 ,the measure of its capacity is the amount of electricity required to raise the potential to a stated amount4 ,the unit of capacity is the farad1 q4 v4 ,electric capacity is comparable to the capacity of a bottle for air4 ,a given amount of air will raise the pressure more or less1 and the amount required to raise its pressure a stated amount might be taken as the measure of capacity1 and would be strictly comparable to electrostatic charge and potential change4 ,the capacity1 ,k1 is obviously proportional to the quantity1 ,q1 of the charge at a given potential1 ,e1 and inversely proportional to the potential1 ,e1 for a given quantity1 ,q1 or1 7#a7 ,k ,q_/,e and 7#b7 ,q ,k 99 ,e1 or1 the quantity required to raise a conductor by a given potential is equal to the capacity of the conductor or system multiplied by the rise of potential4 ,the capacity of a conductor depends upon its environments1 such as the nature of the dielectric surrounding it1 the proximity of oppositely charged bodies and other similar factors4 7,see ,dielectric-,condenser-,leyden jar47 ,the dimensions of capacity are found by dividing a quantity of electricity by the potential produced in the conductor by such quantity4 ,quantity 7 77,m4#e7997,l#a4e77 _/ ,t 7 _/ potential 7 77,m4#e7997,l4#e77 _/ ,t 7 ,l4 ,capacity1 ,instantaneous4 ,the capacity of a condenser when connected only for an instant to a source of electricity4 ,this is in contrast to electric absorption 7see ,absorption1 ,electric71 and is capacity without such absorption taking part in the action4 #ajc ,,standard ,,electrical ,,dictionary4 ,capacity of a ,telegraph ,conductor4 ,the electric capacity of a telegraphic conductor is identical in quality with that of any other conductor4 ,it varies in quantity1 not only for different wires1 but for the same wire under different environments1 as the wire reacting through the surrounding air or other dielectric upon the earth1 represents one element of a condenser1 the earth1 in general1 representing the other4 ,hence1 a wire placed near the earth has greater capacity than one strung upon high poles1 although the wires may be identical in length1 material and diameter4 ,the effect of high capacity is to retard the transmission of intermitting signals4 ,thus1 when--as in the ,morse system--a key is depressed1 closing a long telegraph current and sending a signal into a line1 it is at least very probable that a portion of the electricity travels to the end of the wire with the velocity of light4 ,but as the wire has to be charged1 enough current to move the relay may not reach the end for some seconds4 ,capacity of ,polarization of a ,voltaic ,cell4 ,the relative resistance to polarization of a voltaic cell1 measured by the quantity of electricity it can supply before polarization4 ,a counter-electromotive force may be developed1 or the acid or other solution may become exhausted4 ,the quantity of electricity delivered before this happens depends on the size and type of cell and other factors4 ,capacity1 ,residual4 ,when two insulated conductors are separated by a dielectric1 and are discharged disruptively by being connected or nearly connected electrically1 on removing the discharger it is found that a slight charge is present after a short interval4 ,this is the residual charge4 7,see ,charge1 ,residual47 ,shaking or jarring the dielectric facilitates the complete discharge4 ,this retaining of a charge is a phenomenon of the dielectric1 and as such1 is termed residual capacity4 ,it varies greatly in different substances4 ,in quartz it is one-ninth what it is in air4 ,iceland spar 7crystalline calcite7 seems to have no residual capacity4 ,the action of shaking and jarring in facilitating a discharge indicates a mechanical stress into which the electrostatic polarization of the conductor has thrown the intervening dielectric4 ,capacity1 ,specific ,inductive4 ,the ratio of the capacity of a condenser when its plates are separated by any substance to the capacity of the same condenser when its plates are separated by air4 ,a static accumulator consists of two conducting surfaces separated by an insulator4 ,it is found that the capacity of an accumulator for an electric charge1 which varies with or may be rated by the potential difference to which its conductors will be brought by the given charge1 varies with the nature of the interposed dielectric1 and is proportional to a constant special to each substance4 ,this constant is the specific inductive capacity of the dielectric4 ,the same condenser will have a higher capacity as the dielectric is thinner1 other things being equal4 ,but different dielectrics having different specific inductive capacities1 the constant may be determined by ascertaining the relative thicknesses of layers having the same total inductive capacity4 ,the thicker the layer1 the higher is its specific inductive capacity4 ,thus it is found that #c4b units thickness of sulphur have the same total inductive capacity as #a unit thickness of air4 ,in other words1 if sulphur is interposed between two conducting plates1 they may be separated to over three times the distance that would be requisite to retain the same capacity in air4 ,hence1 sulphur is the better dielectric1 and air being taken as unity1 the specific inductive capacity of sulphur is #c4b4 #ajd ,,standard ,,electrical ,,dictionary4 ,the specific inductive capacity of a dielectric varies with the time and temperature4 ,that of glass rises #b4e per cent4 between #ab ,c4 7#ec4f ,f47 and #hc ,c4 7#aha4d ,f474 ,if a condenser is discharged disruptively1 it retains a small residual charge which it can part with later4 ,if a metallic connection is made between the plates1 the discharge is not instantaneous4 ,vibration shaking and jarring facilitate the complete discharge4 ,all this shows that the charge is a phase of the dielectric itself1 and indicates a strained state into which it is brought4 ,the following table gives the specific inductive capacity of various substances3 ,specific ,inductive ,capacity4 ,substance ,specific ,inductive ,authority ,capacity4 ,vacuum1 air at about #j4jja millimeters pressure #j4id about ,ayrton ,vacuum1 air at about #e millimeters #j4iihe ,ayrton #j4iiida ,boltzmann ,hydrogen at about #gfj millimeters pressure #j4iiig ,boltzmann #j4iiih ,ayrton ,air at about #gfj millimeters pressure #a4j ,taken as the standard ,carbon ,dioxide at about #gfj millimeters pressure #a4jjjcef ,boltzmann #a4jjjh ,ayrton ,olefiant ,gas at about #gfj millimeters pressure #a4jjjgbb ,boltzmann ,sulphur ,dioxide at about #gfj millimeters pressure #a4jjcg ,ayrton ,paraffin ,wax1 ,clear #a4ib ,schiller #a4if ,wllner #a4igg ,gibson and ,barclay #b4cb ,boltzmann ,paraffin ,wax1 ,milky #b4dg ,schiller ,india ,rubber1 ,pure #b4cd ,schiller ,india ,rubber1 ,vulcanized #b4id ,schiller ,resin #b4ee ,boltzmann ,ebonite #b4ef ,wllner #b4gf ,schiller #c4ae ,boltzmann ,sulphur #b4hh to #c4ba ,wllner #c4hd ,boltzmann ,shellac #b4ie to #c4gc ,wllner ,gutta percha #d4b ,mica #e ,flint ,glass1 ,very light #f4eg ,j4 ,hopkinson ,flint ,glass1 ,light #f4he ,j4 ,hopkinson ,flint ,glass1 ,dense #g4d ,j4 ,hopkinson ,flint ,glass1 ,double extra dense #aj4a ,j4 ,hopkinson #aje ,,standard ,,electrical ,,dictionary4 ,capacity1 ,unit of4 ,the unit of capacity is the capacity of a surface which a unit quantity will raise to a unit potential4 ,the practical unit is the surface which a coulomb will raise to one volt1 and is called the farad1 q4 v4 ,capacity1 ,storage4 ,in secondary batteries the quantity of electrical current which they can supply when charged1 without undue exhaustion4 ,it is expressed in ampere-hours4 ,the potential varies so little during the discharge that it is assumed to be constant4 ,capillarity4 ,the reaction between liquid surfaces of different kinds or between liquid and solid surfaces due to surface tension4 ,its phenomena are greatly modified by electric charging1 which alters the surface tension4 ,capillarity is the cause of solutions creeping1 as it is termed4 ,thus in gravity batteries a crust of zinc sulphate often formed over the edge of the jar due to the solution creeping and evaporating4 ,as a liquid withdraws from a surface which it does not wet1 creeping as above is prevented by coating the edge with paraffin wax1 something which water does not moisten4 ,it also causes the liquids of a battery cell to reach the connections and injure them by oxidation4 ,the solutions creep up in the pores of the carbons of a battery and oxidize the clamps4 ,to give good connections a disc of platinum or of lead is used for the contact as not being attacked4 ,another way is to dip the upper ends of the dry and warm carbons into melted paraffin wax1 or to apply the wax to the hot carbons at the top1 and melt it in with a hot iron4 #ajf ,,standard ,,electrical ,,dictionary4 ,carbon4 7a7 ,one of the elements2 atomic weight1 #ab4 ,it exists in three allotropic modifications1 charcoal1 graphite and diamond4 ,in the graphitic form it is used as an electric current conductor1 as in batteries and for arc lamp1 electrodes and incandescent lamp filaments4 ,it is the only substance which conducts electricity and which cannot be melted with comparative ease by increase of current4 7,see ,resistance47 7b7 ,the carbon plate of a battery or rod of an arc lamp4 ,to secure greater conductivity in lamp carbons1 they are sometimes plated with nickel or with copper4 7c7 v4 ,to place carbons in arc lamps4 ,this has generally to be done once in twenty-four hours1 unless the period of burning is very short4 ,carbon1 ,artificial4 ,for lamps1 carbons and battery plates carbons are made by igniting1 while protected from the action of the air1 a mixture of carbon dust and a cementing and carbonizable substance4 ,lamp black may be added also4 ,powdered coke or gas carbon is mixed with molasses1 coal tar1 syrup1 or some similar carbonaceous liquid4 ,it is moulded into shape4 ,for lamp carbons the mixture is forced from a vessel through a round aperture or die1 by heavy pressure1 and is cut into suitable lengths4 ,for battery plates it may be simply pressed into moulds4 ,the carbons are ignited in covered vessels and also covered with charcoal dust1 lamp black or its equivalent4 ,they are heated to full redness for some hours4 ,after removal and cooling they are sometimes dipped again into the liquid used for cementing and reignited4 ,great care in securing pure carbon is sometimes necessary1 especially for lamps4 ,fine bituminous coal is sometimes used1 originally by ,robert ,bunsen1 in #ahch or #ahdj2 purification by different processes has since been applied2 carbon from destructive distillation of coal tar has been used4 ,the famous ,carr carbons are made1 it is said1 from #ae parts very pure coke dust1 five parts calcined lamp-black1 and seven or eight parts sugar--syrup mixed with a little gum4 ,five hours heating1 with subsequent treatment with boiling caramel and reignition are applied4 ,the latter treatment is termed nourishing4 ,napoli used three parts of coke to one of tar4 ,sometimes a core of different carbon than the surrounding tube is employed4 #ajg ,,standard ,,electrical ,,dictionary4 ,the following are the resistances of ,carr's carbons per meter 7#ci4cg inches73 ,diameter in ,diameter in ,resistance in ,ohms4 ,millimeters4 ,inches4 #bj ,c4 7#ih ,f47 #a 4#jci #ej4jjj #b 4#jgh #ab4e #c 4#aag #e4ee #d 4#aef #c4abe #e 4#aie #b4jjj #f 4#bcd #a4cij #h 4#cab 4#gha #aj 4#cij 4#e #ab 4#dfh 4#cdh #ae 4#ehe 4#bbb #ah 4#gjb 4#aed #bj 4#ghj 4#abe ,at high temperatures the resistance is about one-third these amounts4 ,a layer of copper may increase the conductivity one hundred times and prolong the duration #ad per cent4 ,thus a layer of copper #a_/fie millimeter 7#a_/agcjj inch7 thick increases the conductivity #d4e times2 a coating #a_/fj millimeter 7#a_/aejj inch7 thick increases the conductivity one hundred and eleven times4 ,carbon1 ,cored4 ,a carbon for arc lamps with a central core of softer carbon than the exterior zone4 ,it fixes the position of the arc1 and is supposed to give a steadier light4 ,synonym--,concentric ,carbon4 ,carbon ,holders4 ,in arc lamps1 the fixed clamps for holding the ends of the carbons4 ,carbonization4 ,the igniting in a closed vessel1 protected from air1 of an organic substance so as to expel from it all the constituents except part of the carbon2 destructive distillation4 7,see ,carbonized ,cloth47 ,carbonized ,cloth4 ,cloth cut in discs and heated in vessels protected from the air1 until reduced to carbon4 ,the heating is sometimes conducted in vacuo4 ,they are placed in a pile in a glass or other insulating tube1 and offer a resistance which can be varied by pressure4 ,the greater the pressure the less will be the resistance1 and vice versa4 ,carbon ,dioxide4 ,a compound gas1 ,,co#b4 ,it is composed of ,carbon1 #ab parts by weight4 ,oxygen4 #cb ,specific gravity1 #a4ebd 7,dulong and ,berzelins74 ,molecular weight1 #dd4 ,it is a dielectric of about the resistance of air4 ,its specific inductive capacity at atmospheric pressures is #a4jjjcef 7,boltzmann74 #a4jjjh 7,ayrton74 ,synonyms--,carbonic ,acid--,carbonic ,acid ,gas4 #ajh ,,standard ,,electrical ,,dictionary ,carbon1 ,volatilization of4 ,in arc lamps the heat is so intense that it is believed that part of the carbon is volatilized as vapor before being burned or oxidized by the oxygen of the air4 ,the same volatilization may take place in incandescent lamps which are overheated4 ,carcel4 ,the standard of artificial illumination used in ,france4 ,it is the light yielded by a standard lamp burning #db grams 7#fdh grains7 of colza oil per hour1 with a flame #dj millimeters 7#a4eg inch7 in height4 ,one carcel is equal to #i4e to #i4f candles4 ,carcel ,lamp4 ,the lamp giving the standard of illuminating power4 ,the wick is cylindrical1 giving an ,argand or central draft flame4 ,it is woven with #ge strands1 and weighs #c4f grams 7#ee4e grains7 per decimeter 7#c4i inches7 of length4 ,the chimney is #bi centimeters 7#aa4c inches7 high1 #dg millimeters 7#a4hh inch7 in diameter at the bottom1 contracting just above the wick to #cd millimeters 7#a4cf inch74 ,carcel ,gas ,jet4 ,a standard ,argand gas burner1 made with proper rating to give the light of a definite number of carcels illuminating power4 ,cognizance must be taken of the quality of the gas as well as of the burner used4 ,carrying ,capacity4 ,in a current conductor1 its capacity for carrying a current without becoming unduly heated4 ,it is expressed in amperes4 7,see ,wire ,gauge1 ,american47 ,cascade4 ,the arrangement of ,leyden jars in series on insulating supports1 as described below4 ,cascade1 ,charging and ,discharging ,leyden ,jars ,in4 ,an arrangement of ,leyden jars in series for the purpose of charging and discharging4 ,they are placed on insulating supports1 the inner coating of one connected with the outer coating of the next one all through the series4 ,the actual charge received by such a series1 the outer coating of one end jar being grounded1 and the inner coating of the other being connected to a source of high potential1 or else the same being connected to electrodes of opposite potentials is no greater than that of a single jar1 but a much higher potential difference can be developed without risk of perforating the glass of a jar4 ,the difference of potential in each jar of the series is equal to the total potential difference divided by the number of jars4 ,the energy of discharge is equal to the same fraction of the energy of a single jar charged with the same quantity4 ,transcriber's note3 ,the equal distribution of potential assumes all the jars have the same capacity4 ,the charge on all jars is the same since they are in series4 #aji ,,standard ,,electrical ,,dictionary4 ,case-hardening1 ,electric4 ,the conversion of the surface of iron into steel by applying a proper carbonaceous material to it while it is heated by an electric current4 ,it is a superficial cementation process4 ,cataphoresis4 ,electric osmore2 the transfer of substances in solution through porous membranes under the influence probably of electrolysis1 but without themselves being decomposed4 ,cautery1 ,electric4 ,an electro-surgical appliance for removing diseased parts1 or arresting hemorrhages1 taking the place of the knife or other cutting instrument4 ,the cautery is a platinum wire heated to whiteness by an electric current1 and when in that condition used to cut off tumors1 stop the flow of blood and parallel operations4 ,the application is painful1 but by the use of anaesthetics pain is avoided1 and the healing after the operation is greatly accelerated4 ,the heated wire of the cautery can be used for cutting operations in many cases where excision by a knife would be almost impracticable4 ,synonyms--,galvano-cautery--,galvano-ca ustry--,galvano-electric1 do4--,galvano-thermal1 do4 ,c4 ,c4 ,a contraction of cubic centimeter4 ,it is often written in small letters1 as #ajj c4c41 meaning #ajj cubic centimeters4 ,cell1 ,constant4 ,a cell which yields a constant and uniform current under unvarying conditions4 ,this implies that neither the electro-motive force or the resistance of the cell shall vary1 or else that as the electro-motive forces run down the resistance shall diminish in proper proportion to maintain a constant current4 ,there is really no constant cell4 ,the constancy is greatest when the external resistance is high in proportion to the internal resistance4 ,cell1 ,electrolytic4 ,a vessel containing the electrolyte1 a liquid decomposable by the current1 and electrodes1 arranged for the passage of a decomposing current4 ,the voltameter1 q4 v41 is an example4 ,cell1 ,standard ,voltaic4 ,a cell designed to be a standard of electro-motive force2 one in which the same elements shall always be present under the same conditions1 so as to develop the same electro-motive force4 ,in use the circuit is closed only for a very short time1 so that it shall not become altered by polarization or exhaustion4 ,cell1 ,standard ,voltaic1 ,daniell's4 ,a zinc-copper-copper sulphate couple4 ,many forms are used4 ,sometimes a number of pieces of blotting paper are interposed between two plates1 one of copper--the other of zinc4 ,the paper next the copper is soaked in copper sulphate solution1 and those next the zinc in zinc sulphate solution1 of course before being put together4 ,sometimes the ordinary porous cup combination is employed4 ,the cut shows a modification due to ,dr4 ,fleming 7,phil4 ,mag4 ,s4 #e1 vol4 xx1 p4 #abf71 which explains itself4 ,the ,u tube is #c_/d-;inch diameter1 and #h inches long4 ,starting with it empty the tap ,a is opened1 and the whole ,u tube filled with zinc sulphate solution1 and the tap ,a is closed4 ,the zinc rod usually kept in the tube ,l is put in place1 tightly corking up its end of the ,u tube4 ,the cock ,c is opened1 which lowers the level of the solution in the right-hand limb of the ,u tube only4 ,the tap ,b is opened and the copper sulphate solution is run in1 preserving the line of separation of the two solutions4 ,the copper rod is taken out of its tube ,m1 and is put in place4 ,india rubber corks are used for both rods4 ,as the liquids begin to mix the mixture can be drawn off at ,c and the sharp line of demarcation re-established4 ,in ,dr4 ,sloane's standard cell two test tubes are employed for the solutions and a syphon is used to connect them4 ,oxidation of the zinc lowers the ,e4 ,m4 ,f42 oxidation of the copper raises it4 ,with solutions of equal sp4 gr4 the ,e4 ,m4 ,f4 is #a4ajd volts4 ,if the copper sulphate solution is #a4ajj sp4 gr4 and the zinc sulphate solution #a4djj sp4 gr41 both at #ae ,c4 7#ei;,f471 the ,e4 ,m4 ,f4 will be #a4jgd volt4 ,clean pure zinc and freshly electrolyzed copper should be used4 ,fig4 #gi ,,standard ,,daniell ,,cell--,,fleming',s ,,form4 #aaj ,,standard ,,electrical ,,dictionary4 ,cell1 ,standard ,voltaic1 ,latimer ,clark's4 ,a mercury and zinc electrode couple with mercurous sulphate as excitant and depolarizer4 ,the positive element is an amalgam of zinc1 the negative is pure mercury4 ,each element1 in a representative form1 the ,h form1 is contained in a separate vessel which communicate by a tube4 ,over the pure mercury some mercurous sulphate is placed4 ,both vessels are filled to above the level of the connecting tube with zinc sulphate solution1 and kept saturated4 ,it is tightly closed or corked4 ,the ,e4 ,m4 ,f4 at #ae ,c 7#ei ,f47 is #a4dch4 ,temperature correction 7#a - 74#jjjgg 997t - #ae ,c7 7 7 t being expressed in degrees centigrade 7,rayleigh74 ,a diminution in specific gravity of the zinc solution increases the ,e4 ,m4 ,f4 ,the cell polarizes rapidly and the temperature coefficient is considered too high4 ,fig4 #hj4 ,,latimer ,,clark',s ,,standard ,,cell4 #aaa ,,standard ,,electrical ,,dictionary4 ,cements1 ,electrical4 ,a few cements find their use in electrical work4 ,marine glue1 ,chatterton's compound1 and sealing wax may be cited4 ,centi-4 ,employed as a prefix to indicate one-hundredth1 as centimeter1 the one-hundredth of a meter2 centi-ampere1 the one-hundredth of an ampere4 ,centigrade-scale4 ,a thermometer scale in use by scientists of all countries and in general use in many4 ,the temperature of melting ice is #j2 the temperature of condensing steam is #ajj 2 the degrees are all of equal length4 ,to reduce to ,fahrenheit degrees multiply by #i and divide by #e1 and add #cb algebraically1 treating all readings below #j as minus quantities4 ,for its relations to the ,reamur scale1 see ,reamur ,scale4 ,its abbreviation is ,c41 as #aj ,c41 meaning ten degrees centigrade4 ,centimeter4 ,a metric system unit of length2 one-hundredth of a meter2 #j4cicg inch4 ,the absolute or c4 g4 s4 unit of length4 ,centimeter-gram-second ,system4 ,the accepted fundamental or absolute system of units1 called the ,c4 ,g4 ,s4 system4 ,it embraces units of size1 weight1 time1 in mechanics1 physics1 electricity and other branches4 ,it is also called the absolute system of units4 ,it admits of the formation of new units as required by increased scope or classification4 ,the following are basic units of the system 3 ,of length1 centimeter2 of mass1 gram2 of time1 second3 of force1 dyne3 of work or energy1 erg4 ,see ,dyne1 ,erg41 and other units in general4 #aab ,,standard ,,electrical ,,dictionary4 ,central ,station ,distribution or ,supply4 ,the system of supplying electric energy in current form from a main generating plant to a district of a number of houses1 factories1 etc4 ,it is in contrast with the isolated plant system in which each house or factory has its own separate generating installment1 batteries or dynamos4 ,centre of ,gravity4 ,a point so situated with respect to any particular body1 that the resultant of the parallel attracting forces between the earth and the several molecules of the body always passes through it4 ,these are resultants of the relative moments of the molecules4 ,if a body is suspended1 as by a string1 the centre of gravity always lies vertically under its point of suspension4 ,by two trials the point of intersection of plumb lines from the point of suspension being determined the centre of gravity is known4 ,the vertical from the point of support coincides with the line of direction4 ,centre of ,gyration4 ,the centre of gyration with respect to the axis of a rotating body is a point at which if the entire mass of the body were concentrated its moment of inertia would remain unchanged4 ,the distance of this point from the axis is the radius of gyration4 ,centre of ,oscillation4 ,the point referred to in a body1 suspended or mounted to swing like a pendulum1 at which if all the mass were concentrated1 #at would complete its oscillations in the same time4 ,the distance from the axis of support to this point gives the virtual length of the pendulum which the body represents4 ,centre of ,percussion4 ,the point in a suspended body1 one free to swing like a pendulum1 at which an impulse may be applied1 perpendicular to the plane through the axis of the body and through the axis of support without shock to the axis4 ,it is identical with the centre of oscillation1 q4 v41 when such lies within the body4 ,centrifugal ,force4 ,the force which draws a body constrained to move in a curved path away from the centre of rotation4 ,it is really due to a tangential impulse and by some physicists is called the centrifugal component of tangential velocity4 ,it has to be provided against in generator and motor armatures1 by winding them with wire or bands to prevent the coils of wire from spreading or leaving their bed upon the core4 #aac ,,standard ,,electrical ,,dictionary4 ,centrifugal ,governor4 ,the usual type of steam-engine governor4 ,the motion of the engine rotates a system of weights1 which are forced outward by centrifugal force1 and are drawn inwards by gravity or by springs4 ,moving outwards they shut off steam1 and moving inwards they admit it1 thus keeping the engine at approximately a constant speed4 ,the connections between them and the steam supply and the general construction vary widely in different governors4 ,c4 ,g4 ,s4 ,abbreviation or symbol for ,centimeter-gram-second1 as the ,c4 ,g4 ,s4 system4 7,see ,centimeter-gram-second ,system47 ,it is sometimes expressed in capitals1 as above1 and sometimes in small letters1 as the c4 g4 s4 unit of resistance4 ,chamber of ,incandescent ,lamp4 ,the interior of the bulb of an incandescent lamp4 7,see ,lamp1 ,incandescent47 ,fig4 #ha4 ,,characteristic ,,curve ,,of ,a ,,dynamo4 ,,fig4 #hb4 ,,drooping ,,characteristic4 ,characteristic ,curve4 ,a curve indicating the variations in electro-motive force developed during the rotations of the armature of a dynamo or other generator of ,e4 ,m4 ,f4 ,the term as used in the electrical sense is thus applied1 although the indicator diagram of a steam engine may be termed its characteristic curve1 and so in many other cases4 ,as the amperes taken from a series generator are increased in number1 the ,e4 ,m4 ,f4 rises1 it may be very rapidly up to a certain point1 and thereafter more slowly4 ,to construct the curve coordinates1 q4 v41 are employed4 ,the resistance of the dynamo and of the outer circuit being known1 the current intensity is measured4 ,to obtain variations in electro-motive force the external resistance is changed4 ,thus a number of ampere readings with varying known resistance are obtained1 and for each one an electro-motive force is calculated by ,ohm's law4 ,from these data a curve is plotted1 usually with volts laid off on the ordinate and amperes on the abscissa4 ,by other methods other characteristic curves may be obtained1 for which the titles under ,curve may be consulted4 #aad ,,standard ,,electrical ,,dictionary4 ,characteristic1 ,drooping4 ,a characteristic curve of a dynamo which indicates a fall in voltage when an excessive current is taken from the dynamo in question4 ,it is shown strongly in some ,brush machines1 and is partly due to the arrangements for cutting out two of the coils as they approach the neutral line4 ,it is an advantage1 as it protects from overheating on short circuit4 ,characteristic1 ,external4 ,in a dynamo the characteristic curve in which the relations of volts between terminals to amperes in the outer circuit are plotted4 7,see ,curve1 ,external ,characteristic47 ,characteristic1 ,internal4 ,a characteristic curve of a shunt dynamo1 in which the relations of volts to amperes in the shunt circuit is plotted4 ,characteristics of ,sound4 ,of interest1 electrically1 as affecting the telephone1 they comprise3 7#a7 ,pitch1 due to frequency of vibrations4 7#b7 ,intensity or loudness1 due to amplitude of waves of sound4 7#c7 ,quality or timbre1 the distinguishing characteristics of any specific sound due to overtones1 discords1 etc41 by which the sound is recognizable from others4 ,the telephone is held by the ,u4 ,s4 courts to be capable of reproducing the voice by means of the undulatory current4 7,see ,current1 ,undulatory47 ,charge4 ,the quantity of electricity that is present on the surface of a body or conductor4 ,if no electricity is supplied1 and the conductor is connected to the earth1 it is quickly discharged4 ,a charge is measured by the units of quantity1 such as the coulomb4 ,the charge that a conductor can retain at a given rise of potential gives its capacity1 expressible in units of capacity1 such as the farad4 ,a charge implies the stretching or straining between the surface of the charged body1 and some complimentary charged surface or surfaces1 near or far1 of large or small area1 of even or uneven distribution4 ,charge4 v4 7a7 ,to introduce an electrostatic charge1 as to charge a condenser4 7b7 ,to decompose the elements of a secondary battery1 q4 v41 so as to render it capable of producing a current4 ,thus1 a spent battery is charged or recharged to enable it to do more work4 ,synonyms--,renovate--,revivify--,rechar ge4 #aae ,,standard ,,electrical ,,dictionary4 ,charge1 ,bound4 ,a charge of electricity borne by the surface of a body so situated with reference to another oppositely charged body1 that the charge is imperceptible to ordinary test1 will not affect an electroscope nor leave the surface if the latter is connected to the earth4 ,to discharge such a body it must be connected to its complimentarily charged body4 ,the bound charge was formerly called dissimulated or latent electricity4 7,see ,charge1 ,free47 ,the charge or portion of a charge of a surface which is neutralized inductively by a neighboring charge of opposite kind4 ,the degree of neutralization or of binding will depend on the distance of the two charged surfaces from one another and on the electro-static nature of the medium intervening1 which must of necessity be a dielectric4 ,a charge not so held or neutralized is termed a free charge4 ,thus a surface may be charged and by the approach of a surface less highly charged may have part of its charge bound4 ,then if connected to earth4 it will part with its unbound or free charge1 but will retain the other until the binding surface is removed1 or until the electricity of such surface is itself bound1 or discharged1 or until connection is made between the two surfaces4 ,thus a body may have both a bound and a free charge at the same time4 ,charge1 ,density of4 ,the relative quantity of electricity upon a given surface4 ,thus a charged surface may have an evenly distributed charge or one of even density1 or an unevenly distributed charge or one of uneven density4 ,in a thunderstorm the earth has a denser charge under the clouds than elsewhere4 ,synonym--,electrical ,density4 ,charge1 ,dissipation of4 ,as every body known conducts electricity1 it is impossible so to insulate a surface that it will not lose its charge by leakage4 ,an absolute vacuum might answer1 and ,crookes in a high vacuum has retained a charge against dissipation for years4 ,the gradual loss is termed as above4 ,charge1 ,distribution of4 ,the relation of densities of charge on different parts of a charged body4 ,on a spherical conductor the charge is normally of even distribution2 on other conductors it is unevenly distributed1 being of greatest density at points1 edges1 and parts of smallest radius of curvature4 ,even distribution can also be disturbed by local induction1 due to the presence of oppositely charged bodies4 #aaf ,,standard ,,electrical ,,dictionary4 ,charge1 ,free4 ,the charge borne by an insulated body1 independent of surrounding objects4 ,theoretically it is an impossibility4 ,a charge always has its compliment somewhere in surrounding objects4 ,as a matter of convenience and convention1 where the complimentary charge is so distributed that its influence is not perceptible the charge is called a free charge4 ,if connected to earth the free charge will leave the body4 ,if the body is connected with an electroscope the free charge will affect the same4 7,see ,charge1 ,bound47 ,charge1 ,residual4 ,when a ,leyden jar or other condenser is discharged by the ordinary method1 after a few minutes standing a second discharge of less amount can be obtained from it4 ,this is due to what is known as the residual charge4 ,it seems to be connected in some way with the mechanical or molecular distortion of the dielectric4 ,the jarring of the dielectric after discharge favors the rapidity of the action1 diminishing the time required for the appearance of the residual charge4 ,the phenomenon1 it will be seen1 is analogous to residual magnetism4 ,this charge is the reciprocal of electric absorption and depends for its amount upon the nature of the dielectric4 7,see ,absorption1 ,electric1 and ,capacity1 ,residual47 ,synonym--,electric ,residue4 ,chatterton's ,compound4 ,a cement used for cementing together layers or sheets of gutta percha1 and for similar purposes in splicing telegraph cables4 ,its formula is3 ,stockholm ,tar1 #a part4 ,resin1 #a part4 ,gutta ,percha1 #c parts4 ,all parts by weight4 ,chemical ,change4 ,when bodies unite in the ratio of their chemical equivalents1 so as to represent the satisfying of affinity or the setting free of thermal or other energy1 which uniting is generally accompanied by sensible heat and often by light1 as in the ignition of a match1 burning of a candle1 and1 when the new compound exhibits new properties distinct from those of its components1 a chemical combination is indicated4 ,more definitely it is a change of relation of the atoms4 ,another form of chemical change is decomposition1 the reverse of combination1 and requiring or absorbing energy and producing several bodies of properties distinct from those of the original compound4 ,thus in a voltaic battery chemical combination and decomposition take place1 with evolution of electric instead of thermal energy4 ,chemical ,equivalent4 ,the quotient obtained by dividing the atomic weight1 q4 v41 of an element by its valency1 q4 v4 ,thus the atomic weight of oxygen is #af1 its valency is #b4 its chemical equivalent is #h4 ,it is the weight of the element corresponding to a unit weight of hydrogen1 either as replacing it1 or combining with it4 ,in electro-chemical calculations the chemical equivalent is often conveniently used to avoid the necessity of dividing by the valency when atomic weights are used4 ,the latter is really the better practice4 ,the atomic weights in the old system of chemical nomenclature were chemical equivalents4 #aag ,,standard ,,electrical ,,dictionary4 ,chemical ,recorder4 ,a form of telegraphic recorder in which the characters1 often of the ,morse alphabet or some similar one1 are inscribed on chemically prepared paper by decomposition affecting the compound with which the paper is charged4 ,in the original chemical recorder of ,bain1 the instrument was somewhat similar to the ,morse recorder1 except that the motionless stylus1 ,s1 always pressing against the paper was incapable of making any mark1 but being of iron1 and the paper strip being impregnated with potassium ferrocyanide1 on the passage of a current a stain of ,prussian blue was produced where the stylus touched the paper4 ,the current passes from the line by way of the iron stylus1 through the paper1 and by way of a brass surface1 ,m1 against which the paper is held and is pressed by the stylus1 to the earth4 ,this recorder is extremely simple and has no part to be moved by the current4 ,the solution in which the paper is dipped contains a mixture of potassium ferrocyanide and ammonium nitrate4 ,the object of the latter is to keep the paper moist4 ,in recent recorders a solution of potassium iodide has been used1 which gives a brown stain of free iodine1 when the current passes4 ,this stain disappears in a few days4 ,fig4 #hc4 ,,bain',s ,,telegraph ,,employing ,,chemical ,,recorder4 ,in the cut1 ,r is the roll of paper1 ,b is a tank of solution with roll1 ,w#a1 for moistening the paper2 ,m is the brass surface against which the stylus1 ,s1 presses the paper1 ,p ,p2 ,w1 ,w are feed rollers2 ,t is the transmitting key1 and zk the battery2 ,pl1 ,pl are earth plates4 ,the apparatus is shown duplicated for each end4 #aah ,,standard ,,electrical ,,dictionary4 ,chemistry4 ,the science treating of atomic and molecular relations of the elements and of chemical compounds of the same4 ,chimes1 ,electric4 ,an apparatus employed to illustrate the principles of the electrostatic charge1 involving the ringing of bells by electrostatic attraction and repulsion4 ,it is used in connection with a frictional1 or influence electric machine4 ,two bells are employed with a button or clapper suspended between them4 ,one bell is connected to one of the prime conductors1 q4 v41 of the machine4 ,the other insulated therefrom is connected to earth1 or if an influence machine is used1 to the other prime conductor4 ,the clappers are hung by a silk thread1 so as to be entirely insulated4 ,on working the machine the bells become oppositely excited4 ,a clapper is attracted to one1 then when charged is repelled and attracted to the other1 it gives up its charge and becoming charged with similar electricity to that of the bell it touches1 is repelled and attracted to the other1 and this action is kept up as long as the excitement continues1 the bells ringing continuously4 ,fig4 #hd4 ,,electric ,,chimes4 ,chronograph1 ,electric4 ,an apparatus for indicating electrically1 and thereby measuring1 the lapse of time4 ,the periods measured may be exceedingly short1 such as the time a photographic shutter takes to close1 the time required by a projectile to go a certain distance1 and similar periods4 ,a drum rotated with even and known velocity may be marked by a stylus pressed upon it by the action of an electro-magnet when a key is touched1 or other disturbance4 ,then the space between two marks would give the period elapsing between the two disturbances of the circuit4 ,as it is practically impossible to secure even rotation of a drum1 it is necessary to constantly measure its rate of rotation4 ,this is effected by causing a tuning-fork of known rate of vibration to be maintained in vibration electrically4 ,a fine point or bristle attached to one of its arms1 marks a sinuous line upon the smoked surface of the cylinder4 ,this gives the basis for most accurately determining the smallest intervals4 ,each wave drawn by the fork corresponds to a known fraction of a second4 ,for projectiles1 the cutting of a wire opens a circuit1 and the opening is recorded instead of the closing4 ,by firing so as to cut two wires at a known distance apart the rate is obtained by the chronograph4 ,synonym--,chronoscope4 #aai ,,standard ,,electrical ,,dictionary4 ,chutaux's ,solution4 ,a solution for bichromate batteries4 ,it is composed as follows3 ,water1 #a1ejj parts ,potassium bichromate1 #ajj parts mercury bisulphate1 #ajj parts #ff sulphuric acid1 #ej parts4 ,circle1 ,galvanic or ,voltaic4 ,a term for the voltaic circuit2 obsolete4 ,fig4 #he4 ,,magic ,,circle4 ,circle1 ,magic4 ,a form of electro-magnet4 ,it is a thick circle of round iron and is used in connection with a magnetizing coil1 as shown1 to illustrate electro-magnetic attraction4 #abj ,,standard ,,electrical ,,dictionary4 ,circuit4 ,a conducting path for electric currents properly forming a complete path with ends joined and including generally a generating device of some kind4 ,part of the conduction may be true and part electrolytic4 7,see ,electrolytic ,conduction47 ,the term has become extended1 so that the term is often applied to any portion of a circuit conveniently considered by itself4 ,the simplest example of a complete circuit would be a circular conductor4 ,if rotated in the earth's field so as to cut its lines of force a current would go through it1 and it would be an electric circuit4 ,another example is a galvanic battery with its ends connected by a wire4 ,here the battery generates the current which1 by electrolytic conduction1 goes through the battery and by true conduction through the wire4 ,for an example of a portion of a circuit spoken of as a circuit see ,circuit1 ,astatic4 ,circuit1 ,astatic4 ,a circuit so wound with reference to the direction of the currents passing through it that the terrestrial or other lines of force have no directive effect upon it1 one member counteracting the other4 ,it may be produced by making the wire lie in two closed curves1 ,a and ,b1 each enclosing an equal area1 one of identical shape and disposition with the other1 and with the current circulating in opposite directions in each one4 ,thus each circuit represents a magnetizing turn of opposite polarity and counteracting each other's directive tendency exhibited in a field of force with reference to an axis a c4 ,another form of astatic circuit is shown in ,fig4 #hf4 ,the portions ,c1 ,d1 lying on opposite sides of the axis of rotation a c1 are oppositely acted on by the earth's directive force as regards the direction of their rotation4 ,figs4 #hf and #hg4 ,,astatic ,,circuits4 ,circuit1 ,branch4 ,a circuit dividing into two or more parts in parallel with each other4 #aba ,,standard ,,electrical ,,dictionary4 ,circuit ,breaker4 ,any apparatus for opening and closing a circuit is thus termed1 but it is generally applied to automatic apparatus4 ,a typical circuit breaker is the hammer and anvil of the induction coil4 7,see ,induction ,coil2 ,anvil47 ,again a pendulum connected to one terminal of a circuit may swing so as to carry a point on its lower end through a globule of mercury as it swings1 which globule is connected to the other terminal4 ,a great many arrangements of this character have been devised4 ,synonym4--,contact ,breaker4 ,circuit ,breaker1 ,automatic4 ,a circuit breaker worked by the apparatus to which it is attached1 or otherwise automatically4 7,see ,induction ,coil2 ,anvil2 ,bell1 ,electric47 ,circuit ,breaker1 ,file4 ,a coarsely cut file1 forms one terminal of an electric circuit1 with a straight piece of copper or steel for the other terminal4 ,the latter terminal drawn along the teeth makes and breaks the contact once for every tooth4 ,the movable piece should have an insulated handle4 ,circuit ,breaker1 ,mercury4 ,a circuit breaker which may be identical in principle1 with the automatic circuit breaker of an induction coil1 but in which in place of the anvil1 q4 v41 a mercury cup is used1 into which the end of a wire dips and emerges as it is actuated by the impulses of the current4 ,each dip makes the contact1 which is broken as the wire springs back4 ,the mercury should be covered with alcohol to protect it from oxidation4 ,circuit ,breaker1 ,pendulum4 ,a circuit breaker in which a pendulum in its swing makes and breaks a contact4 ,it may be kept in motion by clockwork1 or by an electro-magnet1 attracting intermittently an armature attached to its rod1 the magnet circuit being opened and closed by the pendulum or circuit breaker itself4 ,a mercury contact may be used with it4 ,fig4 #hh4 ,,pendulum ,,circuit ,,breaker4 #abb ,,standard ,,electrical ,,dictionary4 ,circuit ,breaker1 ,tuning ,fork4 ,a circuit breaker in which a tuning fork makes and breaks the circuit4 ,each vibration of one of the prongs in one direction makes a contact1 and the reverse vibration breaks a contact4 ,the adjustment is necessarily delicate1 owing to the limited amplitude of the motion of the fork4 ,the fork is kept in vibration sometimes by an electro-magnet1 which is excited as the circuit is closed by the fork4 ,one leg of the fork acts as the armature of the magnet1 and is attracted according to its own natural period4 ,circuit ,breaker1 ,wheel4 ,a toothed wheel with a spring bearing against its teeth4 ,one terminal of a circuit connects with the wheel through its axle1 the other connects with the spring4 ,when the wheel is turned the circuit is opened and closed once for each tooth4 ,the interstices between teeth on such a wheel may be filled with insulating material1 giving a cylindrical surface for the contact spring to rub on4 ,fig4 #hi--,,toothed ,,wheel ,,circuit ,,breaker4 ,circuit1 ,closed4 ,a circuit whose electric continuity is complete2 to make an open circuit complete by closing a switch or otherwise is to close1 complete1 or make a circuit4 ,synonyms--,completed ,circuit--,made ,circuit4 ,circuit1 ,compound4 ,a circuit characterized by compounding of generating or receiving devices1 as including several separate batteries1 or several motors1 or other receiving devices4 ,it is sometimes used to indicate a circuit having its battery arranged in series4 ,it should be restricted to the first definition4 #abc ,,standard ,,electrical ,,dictionary4 ,circuit1 ,derived4 ,a partial circuit connected to two points of another circuit1 so as to be in parallel with the portion thereof between such two points2 a shunt circuit4 ,synonyms--,shunt ,circuit--,derivative ,circuit--,parallel ,circuit4 ,circuit1 ,electric1 ,active4 ,a circuit through which a current passes4 ,the circuit itself need only be a conducting ring1 or endless wire4 ,generally it includes1 as part of the circuit1 a generator of electro-motive force1 and through which generator by conduction1 ordinary or electrolytic1 the same current goes that passes through the rest of the circuit4 ,one and the same current passes through all parts of a series circuit when such current is constant4 ,a current being produced by electro-motive force1 and electromotive force disappearing in its production in an active circuit1 there must be some source of energy which will maintain electromotive force against the drain made upon it by the current4 ,the simplest conception of an active electric circuit is a ring or endless conductor swept through a field of force so as to cut lines of force4 ,a simple ring dropped over a magnet pole represents the simplification of this process4 ,in such a ring a current1 exceedingly slight1 of course1 will be produced4 ,in this case there is no generator in the circuit4 ,an earth coil 7see ,coil1 ,earth17 represents such a circuit1 with the addition1 when experimented with1 of a galvanometer in the circuit4 ,in practice1 a circuit includes a generator such as a battery or dynamo1 and by conductors is led through a continuous path4 ,electric lamps1 electrolytic cells1 motors and the like may be included in it4 ,the term circuit is also applied to portions of a true circuit1 as the internal circuit1 or external circuit4 ,a certain amount of elasticity is allowed in its use4 ,it by no means necessarily indicates a complete through circuit4 ,circuit1 ,electrostatic4 7a7 ,a circuit through which an electrostatic or high tension discharge takes place4 ,it is virtually an electric circuit4 7b7 ,the term is applied also to the closed paths of electrostatic lines of force4 ,circuit1 ,external4 ,the portion of a circuit not included within the generator4 ,circuit1 ,grounded4 ,a circuit1 one of whose members1 the return circuit1 is represented by the earth1 so that the earth completes the circuit4 ,in telegraphy each end of the line is grounded or connected to an earth-plate1 q4 v41 or to the water or gas-pipes1 and the current is assumed to go through the earth on its return4 ,it really amounts to a discharging at one end1 and charging at the other end of the line4 ,the resistance of the earth is zero1 but the resistance of the grounding or connection with the earth may be considerable4 ,synonyms--,ground ,circuit--,earth ,circuit--,single ,wire ,circuit4 ,transcriber's note3 ,the resistance of the earth is high enough that large power system return currents may produce dangerous voltage gradients when a power line is shorted to the ground4 ,don't walk near downed lines6 #abd ,,standard ,,electrical ,,dictionary4 ,circuit ,indicator4 ,a pocket compass1 decomposition apparatus1 galvanometer or other device for indicating the condition of a wire1 whether carrying a current or not1 and1 if carrying one1 its direction1 and sometimes roughly indicating its strength4 ,circuit1 ,internal4 ,the portion of an electric circuit included within the generator4 ,circuit1 ,line4 ,the portion of a circuit embracing the main line or conductor1 as in a telegraph circuit the line carried on the poles2 distinguished from the local circuit 7see ,circuit1 ,local17 in telegraphy4 ,circuit1 ,local4 ,in telegraphy1 a short circuit with local generator or battery included1 contained within the limits of the office or station and operated by a relay1 q4 v4 ,this was the original local circuit2 the term is applicable to any similar arrangement in other systems4 ,referring to the cut1 the main line circuit includes the main battery1 ,e1 ,key1 ,p1 ,relay1 ,r1 ground plates1 ,g1 ,g#a4 ,the relay magnet opens and closes the local circuit with its local battery1 ,l1 and sounder magnet1 ,h1 with its armature1 ,b4 ,the minor parts1 such as switches1 are omitted4 ,fig4 #ij4 ,,local ,,circuit ,,of ,,telegraph ,,system4 ,circuit1 ,local ,battery4 ,a local circuit worked by and including a local battery in its course4 #abe ,,standard ,,electrical ,,dictionary4 ,circuit1 ,loop4 ,a minor circuit introduced in series into another circuit by a cut-out1 or other device1 so as to become a portion of the main circuit4 ,circuit ,loop ,break4 ,a supporter or bracket with two arms for carrying insulators4 ,its use is to enable a loop connection to be introduced into a line which is cut1 so as to enable the connection of the ends of the loop to be made1 one to each end of the through wire1 which ends are attached1 one to each of the two insulators4 ,circuit1 ,main4 ,the circuit including the main line and apparatus supplied by the main battery1 as distinguished from the local circuit4 7,see ,circuit1 ,local47 ,circuit1 ,main ,battery4 ,the main circuit1 including the main or principal battery in its course4 ,circuit1 ,metallic4 ,a circuit in which the current outside the generator1 or similar parts1 is carried on a metallic conductor2 a circuit without any ground circuit4 ,the including of a galvanic battery or electro plating bath would not prevent the application of the term2 its essential meaning is the omission of the earth as the return circuit4 ,circuit1 ,negative ,side of4 ,the side of a circuit opposite to the positive side4 7,see ,circuit1 ,positive ,side of7 ,it is defined as the half of a circuit leading to the positive terminal of the generator4 ,circuit1 ,open4 ,a circuit with its continuity broken1 as by disconnecting a wire from the battery1 or opening a switch2 a broken circuit is its synonym4 ,to open a switch or disconnect or cut the wire is termed opening or breaking the circuit4 ,synonyms--,incomplete ,circuit--,broken ,circuit4 ,circuit1 ,positive ,side of4 ,this side is such that an observer standing girdled by the current with his head in the positive side or region1 would see the current pass around him from his right toward his left hand4 ,it is also defined as the half of the circuit leading to the negative terminal of the generator4 ,circuit1 ,recoil4 ,the portion of a parallel circuit presenting an alternative path1 q4 v41 for a disruptive discharge4 ,circuit1 ,return4 7a7 ,the part of a circuit extending from the generator to the extreme point in general1 upon which no apparatus is placed4 ,in telegraph systems the ground generally forms the return circuit4 ,the distinction of return and working circuit cannot always be made4 7b7 ,it may also be defined as the portion of a circuit leading to the negative terminal of the generator4 #abf ,,standard ,,electrical ,,dictionary ,circuits1 ,forked4 ,circuits starting in different paths or directions from one and the same point4 ,circuit1 ,simple4 ,a circuit containing a single generator1 and single receiver of any kind1 such as a motor or sounder1 with a single connecting conductor4 ,it is also used to indicate arrangement in multiple arc1 but not generally1 or with approval4 ,circuits1 ,parallel4 ,two or more conductors starting from a common point and ending at another common point are termed1 parallel circuits1 although really but parts of circuits4 ,if of equal resistance their joint resistance is obtained by dividing the resistance of one by the number of parallel circuits4 ,if of unequal resistance r1 r'1 r 1 etc41 the formula for joint resistance1 ,r1 of two is ,r 7 r 99 r' 7 _/ 7 r r' 7 ,this resistance may then be combined with a third one by the same formula1 and thus any number may be calculated4 ,synonym--,shunt ,circuit4 ,circuit1 ,voltaic4 ,properly a circuit including a conductor and voltaic couple4 ,it is also applied to the electric circuit1 q4 v41 or to any circuit considered as a bearer of current electricity4 ,circular ,units4 ,units of area1 usually applied to cross sectional area of conductors1 by whose use area is expressed in terms of circle of unit diameter1 usually a circular mil1 which is the area of a circle of one-thousandth of an inch diameter1 or a circular millimeter1 which is the area of a circle of one millimeter diameter4 ,thus a wire one-quarter of an inch in diameter has an area of #bej circular mils2 a bar one centimeter in diameter has an area of ten circular millimeters4 ,transcriber's ,note3 ,area is the diameter squared4 ,a #a_/d inch wire has #fbejj circular mils of area4 ,a one centimeter 7#aj millimeter7 wire has #ajj circular millimeters of area4 ,actual area circular mils 99 7,,pi_/#d74 ,circumflux4 ,the product of the total number of conductor turns on the armature of a dynamo or motor1 into the current carried thereby4 ,for two pole machines it is equal to twice the armature ampere-turns2 for four pole machines to four times such quantity1 and so on4 ,clamp4 ,the appliance for grasping and retaining the end of the rod that holds a carbon in the arc lamp4 ,clark's ,compound4 ,a cement used for the outside of the sheath of telegraph cables4 ,its formula is3 ,mineral ,pitch1 #fe parts4 ,silica1 #cj parts4 ,tar1 #e parts4 ,all parts by weight4 #abg ,,standard ,,electrical ,,dictionary4 ,cleats4 ,a support2 a short block of wood1 grooved transversely1 for holding electric wires against a wall4 ,for the three wire system three grooves are used4 ,the entire wiring of apartments is sometimes done by the cleat system1 using cleats instead of battens1 q4 v41 or mouldings4 ,the cleats are secured against the wall with the grooves facing it1 and the wires are introduced therein4 ,fig4 #ia4 ,,two ,,wire ,,cleat4 ,fig4 #ib4 ,,three ,,wire ,,cleat4 ,cleat1 ,crossing4 ,a cleat with grooves or apertures to support wires which cross each other4 ,two or three grooves are transverse1 and on the under side1 as above2 one groove is longitudinal and on the upper side4 ,cleavage1 ,electrification by4 ,if a mass of mica is rapidly split in the dark a slight flash is perceived4 ,becquerel found that in such separation the two pieces came away oppositely charged with electricity4 ,the splitting of mica is its cleavage4 ,clock1 ,controlled4 ,in a system of electric clocks1 the clocks whose movements are controlled by the current1 regulated by the master or controlling clock4 ,synonym--,secondary ,clock4 ,clock1 ,controlling4 ,in a system of electric clocks the master clock which controls the movements of the others1 by regulating the current4 ,synonym--,master ,clock4 ,clock1 ,electric ,annunciator4 ,a clock operating any form of electric annunciator1 as dropping shutters1 ringing bells1 and the like4 ,it operates by the machinery closing circuits as required at any desired hour or intervals4 #abh ,,standard ,,electrical ,,dictionary4 ,clock1 ,electrolytic4 ,a clock worked by the electrolytic deposition and resolution of a deposit of metal upon a disc4 ,it is the invention of ,nikola ,tesla4 ,a metallic disc is mounted on a transverse axis1 so as to readily rotate4 ,it is immersed in a vessel of copper sulphate4 ,a current is passed through the bath1 the terminals or electrodes being near to and facing the opposite edges of the disc1 so that the line connecting the electrodes lies in the plane of the disc4 ,if a current is passed through the solution by the electrodes1 copper is deposited on one side of the disc1 and as it rotates under the influence of the weight thus accumulated on one side1 the same metal as it is brought to the other side of the disc is redissolved4 ,thus a continuous rotation is maintained4 ,the cause of the deposition and solution is the position of the disc2 one-half becomes negative and the other positive in their mutual relations4 ,clock1 ,self-winding ,electric4 ,a clock which is wound periodically by an electric motor and battery4 ,clockwork1 ,feed4 ,in arc-lamps the system of feeding the carbon or carbons by clockwork whose movements are controlled by the resistance of the arc4 ,this system is employed in the ,serrin1 and in the ,gramme regulators1 among others4 ,the carbons1 if they approach1 move clockwork4 ,the movement of this is stopped or freed by an electro-magnet placed in shunt around the arc and carbons4 ,cloisons4 ,partitions or divisions2 applied to the winding of electro-magnets and coils where the winding is put on to the full depth1 over single sections of the core1 one section at a time1 until the whole core is filled up4 ,closure4 ,the closing or completion of a circuit by depressing a key or moving a switch4 ,clutch4 ,in arc lamps a device for the feed of the upper carbons4 ,in its simplest form it is simply a plate or bar pierced with a hole through which the carbon passes loosely4 ,the action of the mechanism raises or lowers one end of the plate or bar4 ,as it rises it binds and clutches the carbon1 and if the action continues it lifts it a little4 ,when the same end is lowered the carbon and clutch descend together until the opposite end of the clutch being prevented from further descent1 the clutch approaches the horizontal position and the rod drops bodily through the aperture4 ,the cut shows the clutches of the ,brush double carbon lamp4 ,in practice the lifting and releasing as regulated by an electro-magnet are so very slight that practically an almost absolutely steady feed is secured4 ,a similar clutch is used in the ,weston lamp4 #abi ,,standard ,,electrical ,,dictionary4 ,clutch1 ,electro-magnetic4 ,a clutch or appliance for connecting a shaft to a source of rotary motion while the latter is in action4 ,in one form a disc1 in whose face a groove has been formed1 which groove is filled with a coil of wire1 is attached to the loose wheel1 while the shaft carries a flat plate to act as armature4 ,on turning on the current the flat plate is attached1 adheres1 and causes its wheel to partake of the motion of the shaft4 ,contact is made by brushes and collecting rings4 ,in the cut1 ,a ,a is the attracted disc2 the brushes1 ,b ,b1 take current to the collecting rings1 ,c4 ,the magnetizing coil is embedded in the body of the pulley1 as shown4 ,fig4 #ic4 ,,clutch ,,of ,,brush ,,lamp4 ,fig4 #id4 ,,electro-,,magnetic ,,clutch4 #acj ,,standard ,,electrical ,,dictionary4 ,coatings of a ,condenser or ,prime ,conductor4 ,the thin conducting coatings of tinfoil1 gold leaf or other conducting substance1 enabling the surface to receive and part with the electric charge readily4 ,without such a coating the charge and discharge would be very slow1 and would operate by degrees only1 as one part of a non-conducting surface might be densely charged and another part be quite devoid of sensible charge4 ,code1 ,cipher4 ,a code of arbitrary words to designate prearranged or predetermined words1 figures or sentences4 ,the systems used in commerce have single words to represent whole sentences or a number of words of a sentence4 ,this not only imparts a degree of secrecy1 but makes the messages much shorter4 ,codes are used a great deal in cable transmission4 ,code1 ,telegraphic4 ,a telegraphic alphabet4 7,see ,alphabets1 ,telegraphic47 ,coefficient4 ,in algebra1 the numerical multiplier of a symbol1 as in the expression #ex1 #e is the coefficient4 ,in physics1 generally a number expressing the ratio or relation between quantities1 one of which is often unity1 as a standard or base of the set of coefficients4 ,thus the coefficient of expansion by heat of any substance is obtained by dividing its volume for a given degree of temperature by its volume at the standard temperature as #j ,c41 or #cb ,f4 ,this gives a fraction by which if any volume of a substance1 taken at #j ,c41 or at whatever may be taken as the basic temperature1 is multiplied1 the expanded volume for the given change of temperature will be obtained as the product4 ,a coefficient always in some form implies the idea of a multiplier4 ,thus the coefficient of an inch referred to a foot would be #a_/ab or 4#hcc1 because any number of inches multiplied by that fraction would give the corresponding number of feet4 ,transcriber's note3 #a_/ab is #j4jhcc ,coefficient1 ,economic4 ,in machinery1 electric generators1 prime motors and similar structures1 the number expressing the ratio between energy absorbed by the device1 and useful1 not necessarily available1 work obtained from it4 ,it is equal to work obtained divided by energy absorbed1 and is necessarily a fraction4 ,if it exceeded unity the doctrine of the conservation of energy would not be true4 ,the economic coefficient expresses the efficiency1 q4 v41 of any machine1 and of efficiencies there are several kinds1 to express any one of which the economic coefficient may be used4 ,thus1 let ,w--energy absorbed1 and w work produced 2 then w_/,w is the economic coefficient1 and for each case would be expressed numerically4 7,see ,efficiency1 ,commercial--,efficiency1 ,electrical--,efficiency of ,conversion47 ,the distinction between useful and available work in a dynamo is as follows3 ,the useful work would include the work expended by the field1 and the work taken from the armature by the belt or other mechanical connection4 ,only the latter would be the available work4 #aca ,,standard ,,electrical ,,dictionary4 ,coercive or ,coercitive ,force4 ,the property of steel or hard iron1 in virtue of which it slowly takes up or parts with magnetic force1 is thus termed 7traditionally2 ,daniell74 ,it seems to have to do with the positions of the molecules1 as jarring a bar of steel facilitates its magnetization or accelerates its parting1 when not in a magnetic field1 with its permanent or residual magnetism4 ,for this reason a permanent magnet should never be jarred1 and permitting the armature to be suddenly attracted and to strike against it with a jar injures its attracting power4 ,coercive force is defined also as the amount of negative magnetizing force required to reduce remnant magnetism to zero4 ,by some authorities the term is entirely rejected1 as the phenomenon does not seem directly a manifestation of force4 ,coil and ,coil ,plunger4 ,a device resembling the coil and plunge1 q4 v41 except that for the plunger of iron there is substituted a coil of wire of such diameter as to enter the axial aperture of the other1 and wound or excited in the same or in the opposite sense1 according to whether attraction or repulsion is desired4 ,coil and ,plunger4 ,a coil provided with a core which is free to enter or leave the central aperture4 ,when the coil is excited1 the core is drawn into it4 ,various forms of this device have been used in arc lamp regulators4 ,synonym--,sucking coil4 ,fig4 #ie4 ,,coil ,,and ,,coil ,,plunger ,,of ,,mengies ,,arc ,,lamp4 ,fig4 #if4 ,,coil ,,and ,,plunger ,,experiment4 #acb ,,standard ,,electrical ,,dictionary4 ,coil and ,plunger1 ,differential4 ,an arrangement of coil and plunger in which two plungers or one plunger are acted on by two coils1 wound so as to act oppositely or differentially on the plunger or plungers4 ,thus one coil may be in parallel with the other1 and the action on the plunger will then depend on the relative currents passing through the coils4 ,coil1 ,choking4 ,a coil of high self-induction1 used to resist the intensity of or choke alternating currents4 ,any coil of insulated wire wound around upon a laminated or divided iron core forms a choking coil4 ,the iron coil is usually so shaped as to afford a closed magnetic circuit4 ,a converter or transformer acts as a choking coil as long as its secondary is left open4 ,in alternating current work special choking coils are used4 ,thus for theatrical work1 a choking coil with a movable iron core is used to change the intensity of the lights4 ,it is in circuit with the lamp leads4 ,by thrusting in the core the self-induction is increased and the current diminishes1 lowering the lamps2 by withdrawing it the self-induction diminishes1 and the current increases4 ,thus the lamps can be made to gradually vary in illuminating power like gas lights1 when turned up or down4 ,synonyms--,kicking ,coil--,reaction ,coil4 ,fig4 #ig4 ,,differential ,,coils ,,and ,,plungers4 ,fig4 #ih4 ,,bisected ,,coils4 #acc ,,standard ,,electrical ,,dictionary4 ,coils1 ,bisected4 ,resistance coils with connections at their centers1 as shown in the diagram4 ,they are used for comparing the resistances of two conductors4 ,the connections are arranged as shown in the coil1 each coil being bisected4 ,for the wires1 movable knife-edge contacts are employed4 ,the principle of the ,wheatstone bridge is used in the method and calculations4 ,coil1 ,earth4 ,a coil of wire mounted with commutator to be rotated so as to cut the lines of force of the earth's magnetic field1 thereby generating potential difference4 ,the axis of rotation may be horizontal1 when the potential will be due to the vertical component of the earth's field1 or the axis may be horizontal1 when the potential will be due to the vertical component1 or it may be set at an intermediate angle4 ,synonym--,delezenne's ,circle4 ,fig4 #ii4 ,,delezenne',s ,,circle ,,or ,,earth ,,coil4 ,coil1 ,electric4 ,a coil of wire used to establish a magnetic field by passing a current through it4 ,the wire is either insulated1 or so spaced that its convolutions do not touch4 ,coil1 ,flat4 ,a coil whose windings all lie in one plane1 making a sort of disc1 or an incomplete or perforated disc4 ,coil1 ,induction4 ,a coil in which by mutual induction the electromotive force of a portion of a circuit is made to produce higher or lower electro-motive force1 in an adjoining circuit1 or in a circuit1 part of which adjoins the original circuit1 or adjoins part of it4 ,an induction coil comprises three principal parts1 the core1 the primary coil and the secondary coil4 ,if it is to be operated by a steady current1 means must be provided for varying it or opening and closing the primary circuit4 ,a typical coil will be described4 #acd ,,standard ,,electrical ,,dictionary4 ,the core is a mass of soft iron preferably divided to prevent extensive ,foucault currents4 ,a cylindrical bundle of soft iron wires is generally used4 ,upon this the primary coil of reasonably heavy wire1 and of one or two layers in depth1 is wrapped1 all being carefully insulated with shellac and paper where necessary4 ,the secondary coil is wrapped upon or over the primary4 ,it consists of very fine wire2 ,no4 #cj to #cf is about the ordinary range4 ,a great many turns of this are made4 ,in general terms the electro-motive force developed by the secondary stands to that of the primary terminals in the ratio of the windings4 ,this is only approximate4 ,the greatest care is required in the insulating4 ,the secondary is sometimes wound in sections so as to keep those parts differing greatly in potential far from each other4 ,this prevents sparking1 which would destroy the insulation4 ,a make and break1 often of the hammer and anvil type1 is operated by the coil4 7,see ,circuit ,breaker1 ,automatic47 ,as the current passes through the primary it magnetizes the core4 ,this attracts a little hammer which normally resting on an anvil completes the circuit4 ,the hammer as attracted is lifted from the anvil and breaks the circuit4 ,the soft iron core at once parts with its magnetism and the hammer falls upon the anvil again completing the circuit4 ,this operation goes on rapidly1 the circuit being opened and closed in quick succession4 ,every closing of the primary circuit tends to produce a reverse current in the secondary1 and every opening of the primary circuit tends to produce a direct current in the secondary4 ,both are of extremely short duration1 and the potential difference of the two terminals of the secondary may be very high if there are many times more turns in the secondary than in the primary4 ,the extra currents interfere with the action of an induction coil4 ,to avoid their interference a condenser is used4 ,this consists of two series of sheets of tin foil4 ,leaves of paper alternate with the sheets of tin-foil1 the whole being built up into a little book4 ,each sheet of tin-foil connects electrically with the sheet next but one to it4 ,thus each leaf of a set is in connection with all others of the same set1 but is insulated from the others4 ,one set of leaves of tin-foil connects with the hammer1 the other with the anvil4 ,in large coils there may be #ge square feet of tin-foil in the condenser4 ,the action of the condenser is to dispose of the direct extra current4 ,when the primary circuit is opened this current passes into the condenser1 which at once discharges itself in the other direction through the coil4 ,this demagnetizes the core1 and the action intensifies and shortens the induced current4 ,the condenser prevents sparking1 and in general improves the action of the coil4 ,many details enter into the construction of coils1 and many variations in their construction obtain4 ,thus a mercury cup into which a plunger dips often replaces the anvil and hammer4 #ace ,,standard ,,electrical ,,dictionary4 ,the induction coil produces a rapid succession of sparks1 which may spring across an interval of forty inches4 ,the secondary generally ends in special terminals or electrodes between which the sparking takes place4 ,a plate of glass1 two inches in thickness1 can be pierced by them4 ,in the great ,spottiswoode coil there are #bhj miles of wire in the secondary1 and the wire is about ,no4 #cf ,a4,w4,g4 ,fig4 #ajj4 ,,vertical ,,section ,,of ,,induction ,,coil4 ,fig4 l#ja4 ,,plan ,,of ,,induction ,,coil ,,connections4 ,induction coils have quite extended use in electrical work4 ,they are used in telephone transmitters1 their primary being in circuit with the microphone1 and their secondary with the line and receiving telephone4 ,in electric welding1 and in the alternating current system they have extended application4 ,in all these cases they have no automatic circuit breaker1 the actuating current being of intermittent or alternating type4 #acf ,,standard ,,electrical ,,dictionary4 ,in the cuts the general construction of an induction coil is shown4 ,in the sectional elevation1 ,fig4 #ajj1 ,a1 is the iron core2 ,b is the primary of coarse wire2 ,c is a separating tube1 which may be of pasteboard2 ,d is the secondary of fine wire2 ,e1 ,e are the binding posts connected to the secondary2 ,h1 ,h are the heads or standards2 ,k1 ,k are the terminals of the primary2 ,f is the vibrating contact spring2 ,g1 a standard carrying the contact screw2 ,j is the condenser with wires1 ,l1 ,m1 leading to it4 ,referring to the plan1 ,fig4 #aja1 ,h represents the primary coil2 ,b and ,a are two of the separate sheets of the condenser1 each sheet with projecting ears2 ,g1 ,g are the heads of the coil2 the dark lines are connections to the condenser4 ,one set of sheets connects with the primary coil at ,c1 and also with the vibrating spring shown in plan and in the elevation at ,f4 ,the other set of sheets connects with the post1 carrying the contact screw4 ,the other terminal of the primary runs to a binding post ,e4 ,f1 in the plan is a binding post in connection with the standard and contact screw4 ,coil1 ,induction1 ,inverted4 ,an induction coil arranged to have a lower electro-motive force in the secondary than in the primary4 ,this is effected by having more convolutions in the primary wire than in the secondary4 ,such coils in practice are used with the alternating current and then do not include a circuit breaker or condenser4 ,they are employed in alternating current system and in electric welding4 7,see ,welding1 ,electric--,converter47 ,in the cut an inverted coil1 as constructed for electric welding is shown4 ,in it the primary coil is marked ,p2 the secondary1 merely a bar of metal1 is marked ,e1 with terminals ,s1 ,s2 the heavy coils1 ,i1 of iron wire are the core2 ,k is a screw for regulating the clamps2 ,j1 ,z is a second one for the same purpose1 while between ,d and ,d' the heat is produced for welding the bars1 ,b1 ,b'1 held in the clamps1 ,c1 ,c'4 ,it will be seen how great may be the difference in turns between the single circle of heavy copper rod or bar which is the secondary of the coil1 and the long coil of wire forming the primary4 ,fig4 #ajb4 ,,inverted ,,induction ,,coil ,,for ,,electric ,,welding4 #acg ,,standard ,,electrical ,,dictionary4 ,coil1 ,induction1 ,telephone4 ,an induction coil used in telephone circuits4 ,it is placed in the box or case near the transmitter4 ,the primary is in circuit with the microphone4 ,the secondary is in circuit with the line and receiving telephone4 ,in the ,bell telephone apparatus the primary of the induction coil is wound with ,no4 #ah to #bd ,a4 ,w4 ,g4 wire to a resistance of #a_/b ohm2 the secondary1 with ,no4 #cf wire to a resistance of #hj ohms4 ,the ,edison telephone induction coil was wound with similar wires to a resistance of #c to #d ohms and of #bej ohms respectively4 ,coil1 ,magnetizing4 ,a coil of insulated wire for making magnets2 and for experimental uses2 it has a short axis and central aperture of as small size as consistent with the diameter of the bar to be magnetized1 which has to pass through it readily4 ,the wire may be quite heavy1 #b or #c millimeters 74#jh--4ab inch7 thick1 and is cemented together with carpenter's glue1 or with shellac or ethereal solution of gum copal4 ,in use it is passed over the bar a few times while a heavy current is going through it4 ,it is used for magic circles also4 7,see ,circle1 ,magic47 ,fig4 #ajc4 ,,magnetizing ,,coil4 ,coil1 ,resistance4 ,a coil constructed for the purpose of offering a certain resistance to a steady current4 ,this resistance may be for the purpose of carrying out quantitative tests1 as in ,wheatstone bridge work 7see ,wheatstone's ,bridge71 or simply to reduce the intensity of a current4 ,for the first class of work the coils are wound so as to prevent the creation of a magnetic field4 ,this is effected by first doubling the wire without breaking it1 and then starting at the bend the doubled wire1 which is insulated1 is wound on a bobbin or otherwise until a proper resistance is shown by actual measurement4 ,the coils are generally contained or set in closed boxes with ebonite tops4 ,blocks of brass are placed on the top1 and one end from one coil and one end from the next connect with the same block4 ,by inserting a plug1 ,p1 so as to connect any two blocks1 which have grooves reamed out for the purpose1 the coil beneath will be short circuited4 ,german silver1 platinoid or other alloy1 q4 v41 is generally the material of the wire4 ,a great object is to have a wire whose resistance will be unaffected by heat4 #ach ,,standard ,,electrical ,,dictionary4 ,fig4 #ajd4 ,,resistance ,,coils ,,and ,,connections1 ,,showing ,,plug4 ,coil1 ,rhumkorff4 ,the ordinary induction coil with circuit breaker1 for use with original direct and constant current1 is thus termed4 7,see ,coil1 ,induction47 ,synonym--,inductorium4 ,coil1 ,ribbon4 ,a coil made of copper ribbon wound flatwise1 often into a disc-like shape1 and insulated by tape or strips of other material intervening between the successive turns4 ,coils1 ,compensating4 ,extra coils on the field magnets of dynamos or motors1 which coils are in series with the armature windings for the purpose of keeping the voltage constant4 ,in compound wound machines the regular series-wound coil is thus termed4 ,in a separately excited dynamo a coil of the same kind in circuit with the armature may be used as a compensator4 ,coils1 ,henry's4 ,an apparatus used in repeating a classic experiment in electro-magnetic induction1 due to ,prof4 ,henry4 ,it consists in a number of coils1 the first and last ones single1 the intermediate ones connected in pairs1 and one of one pair placed on the top of one of the next pair4 ,on opening or closing the circuit of an end coil the induced effect goes through the series and is felt in the circuit of the other end coil4 ,prof4 ,henry extended the series so as to include seven successive inductions1 sometimes called inductions of the first1 second1 third and other orders4 ,frequently ribbon coils 7see ,coil1 ,ribbon17 are used in these experiments4 ,coils1 ,sectioned4 ,a device for prolonging the range of magnetic attraction4 ,it consists of a series of magnetizing coils traversed by an iron plunger4 ,as it passes through them1 the current is turned off the one in the rear or passing to the rear and turned into the next one in advance4 ,the principle was utilized in one of ,page's electric motors about #ahej1 and later by others4 ,the port-electric railroad1 q4 v41 utilizes the same principle4 #aci ,,standard ,,electrical ,,dictionary4 ,collecting ,ring4 ,in some kinds of generators instead of the commutator a pair of collecting rings of metal1 insulated from the machine and from each other1 are carried on the armature shaft4 ,a brush1 q4 v41 presses on each1 and the circuit terminals connect to these two brushes4 ,such rings are employed often on alternating current generators1 where the current does not have to be changed or commuted4 ,collecting rings with their brushes are used also where a current has to be communicated to a revolving coil or circuit as in the magnetic car wheel1 the cut of which is repeated here4 ,the coil of wire surrounding the wheel and rotating with it has to receive current4 ,this it receives through the two stationary brushes which press upon two insulated metallic rings1 surrounding the shaft4 ,the terminals of the coil connect one to each ring4 ,thus while the coil rotates it constantly receives current1 the brushes being connected to the actuating circuit4 ,fig4 #aje4 ,,magnetic ,,car ,,wheel ,,showing ,,collecting ,,rings ,,and ,,brushes4 ,collector4 7a7 ,a name for the brush1 q4 v41 in mechanical electric generators1 such as dynamos1 a pair of which collectors or brushes press on the commutator or collecting rings1 and take off the current4 7b7 ,the pointed connections leading to the prime conductor on a static machine for collecting the electricity2 often called combs4 ,the points of the combs or collectors face the statically charged rotating glass plate or cylinder of the machine4 ,colombin4 ,the insulating material between the carbons in a ,jablochkoff candle or other candle of that type4 ,kaolin was originally used4 ,later a mixture of two parts calcium sulphate 7plaster of ,paris7 and one part barium sulphate 7barytes7 was substituted4 ,the colombin was three millimeters 74#ab inch7 wide1 and two millimeters 74#jh inch7 thick4 7,see ,candle1 ,jablochkoff47 ,column1 ,electric4 ,an old name for the voltaic pile1 made up of a pile of discs of copper and zinc1 with flannel discs1 wet with salt solution or dilute acid1 between each pair of plates4 #adj ,,standard ,,electrical ,,dictionary4 ,comb4 ,a bar from which a number of teeth project1 like the teeth of a comb4 ,it is used as a collector of electricity from the plate of a frictional or influence electric machine2 it is also used in a lightning arrester to define a path of very high resistance but of low self-induction1 for the lightning to follow to earth4 ,communicator4 ,the instrument by which telegraph signals are transmitted is sometimes thus termed4 ,commutator4 ,in general an apparatus for changing4 ,it is used on electric current generators1 and motors1 and on induction coils1 and elsewhere1 for changing the direction of currents1 and is of a great variety of types4 ,synonym--,commuter 7but little used74 ,fig4 #ajf4 ,,dynamo ,,or ,,motor ,,commutator4 ,commutator ,bars4 ,the metallic segments of a dynamo or motor commutator4 ,commutator1 ,flats in4 ,a wearing away or lowering in level of one or more metallic segments of a commutator4 ,they are probably due in many cases to sparking1 set up by periodic springing in the armature mounting1 or by defective commutator connections4 ,commutator of ,current ,generators and ,motors4 ,in general a cylinder1 formed of alternate sections of conducting and non-conducting material1 running longitudinally or parallel with the axis4 ,its place is on the shaft of the machine1 so that it rotates therewith4 ,two brushes1 q4 v41 or pieces of conducting material1 press upon its surface4 #ada ,,standard ,,electrical ,,dictionary4 ,as a part of electric motors and generators1 its function is to collect the currents produced by the cutting of lines of force so as to cause them all to concur to a desired result4 ,the cut shows the simplest form of commutator1 one with but two divisions4 ,its object may be to enable a current of constant direction to be taken from a rotating armature1 in which the currents alternate or change direction once in each rotation4 ,it is carried by the shaft ,a of the armature and rotates with it4 ,it consists of two leaves1 ,s ,s1 to which the terminals of the armature are connected4 ,two springs1 ,w ,w1 the terminals of the outer circuit1 press against the leaves4 ,the springs which do this take off the current4 ,it is so placed1 with reference to the springs and armature1 that just as the current changes in direction1 each leaf changes from one spring to the other4 ,thus the springs receive constant direction currents4 ,the changing action of this commutator appears in its changing the character of the current from alternating to constant4 ,were two insulated collecting rings used instead of a commutator1 the current in the outer circuit would be an alternating one4 ,on some dynamos the commutator has a very large number of leaves4 ,taking the ,gramme ring armature1 there must be as many divisions of the commutator as there are connections to the coils4 ,in this case the function of the commutator is simply to lessen friction1 for the brushes could be made to take current from the coils directly outside of the periphery of the ring4 ,commutator1 ,split ,ring4 ,a two-division commutator for a motor2 it consists of two segments of brass or copper plate1 bent to arcs of a circle1 and attached to an insulating cylinder4 ,they are mounted on the revolving spindle1 which carries the armature1 and acts as a two part commutator4 ,for an example of its application1 see ,armature1 ,revolving1 ,page's4 7,see also ,fig4 #ajg47 ,fig4 #ajg4 ,,section ,,of ,,split ,,ring ,,commutator1 ,,with ,,brushes4 ,compass4 ,an apparatus for utilizing the directive force of the earth upon the magnetic needle4 ,it consists of a circular case1 within which is poised a magnetized bar of steel4 ,this points approximately to the north1 and is used on ships and elsewhere to constantly show the direction of the magnetic meridian4 ,two general types are used4 ,in one the needle is mounted above a fixed card or dial1 on which degrees or points of the compass1 q4 v41 are inscribed4 ,in the other the card is attached to the needle and rotates with it4 ,the latter represents especially the type known as the mariner's compass4 7,see ,compass1 ,mariner's--,compass1 ,spirit1 and other titles under compass1 also ,magnetic ,axis--,magnetic ,elements47 ,the needle in good compasses carries for a bearing at its centre1 a little agate cup1 and a sharp brass pin is the point of support4 ,compass1 ,azimuth4 ,a compass with sights on one of its diameters2 used in determining the magnetic bearing of objects4 #adb ,,standard ,,electrical ,,dictionary4 ,compass ,card4 ,the card in a compass2 it is circular in shape1 and its centre coincides with the axis of rotation of the magnetic needle2 on it are marked the points of the compass1 at the ends generally of star points4 7,see ,compass1 ,points of the47 ,it may be fixed1 and the needle may be poised above it1 or it may be attached to the needle and rotate with it4 ,compass1 ,declination4 ,an instrument by which the magnetic declination of any place may be determined4 ,it is virtually a transit instrument and compass combined1 the telescope surmounting the latter4 ,in the instrument shown in the cut1 ,l is a telescope mounted by its axis1 ,x1 in raised journals with vernier1 ,k1 and arc x1 for reading its vertical angle1 with level n4 ,the azimuth circle1 ,q1 ,r1 is fixed4 ,a vernier1 ,v is carried by the box1 ,a1 ,e1 and both turn with the telescope4 ,a very light lozenge-shaped magnetic needle1 a1 b1 is pivoted in the exact centre of the graduated circles1 ,q ,r1 and ,m4 ,the true meridian is determined by any convenient astronomical method1 and the telescope is used for the purpose4 ,the variation of the needle from the meridian thus determined gives the magnetic declination4 ,,fig4 #ajh4 ,,declination ,,compass4 ,compass1 ,inclination4 ,a magnetic needle mounted on a horizontal axis at its centre of gravity1 so as to be free to assume the dip1 or magnetic inclination1 when placed in the magnetic meridian4 ,it moves over the face of a vertical graduated circle1 and the frame also carries a spirit level and graduated horizontal circle4 ,in use the frame is turned until the needle is vertical4 ,then the axis of suspension of the needle is in the magnetic meridian4 ,the vertical circle is then turned through #ij of the horizon1 which brings the plane of rotation of the needle into the magnetic meridian1 when it assumes the inclination of the place4 #adc ,,standard ,,electrical ,,dictionary4 ,compass1 ,mariner's4 ,a compass distinguished by the card being attached to and rotating with the needle4 ,a mark1 the lubber's mark of the sailors is made upon the case4 ,this is placed so that the line connecting it1 and the axis of rotation of the card is exactly in a plane1 passing through the keel of the ship4 ,thus however the ship may be going1 the point of the card under or in line with the lubber's mark1 shows how the ship is pointing4 ,the case of the mariner's compass is often bowl-shaped and mounted in gimbals1 a species of universal joint1 so as to bc always horizontal4 7,see ,compass1 ,spirit-,gimbals47 ,,fig4 #aji4 ,,mariner',s ,,compass4 ,compass1 ,points of the4 ,the circle of the horizon may bc and is best referred to angular degrees4 ,it has also been divided into thirty-two equiangular and named points4 ,a point is #aa4be4 ,the names of the points are as follows3 ,north1 ,north by ,east1 ,north ,north-east1 ,north-east by ,north1 ,north-east1 ,north-east by ,east1 ,east ,north-east1 ,east by ,north1 ,east1 ,east by ,south1 ,east ,south-east1 ,south-east by ,east1 ,south-east1 ,south-east by ,south1 ,south ,south-east1 ,south by ,east1 ,south1 ,south by ,west1 ,south ,south-west1 ,south-west by ,south1 ,south-west1 ,south-west by ,west1 ,west ,south-west1 ,west by ,south1 ,west1 ,west by ,north1 ,west ,north-west1 ,north-west by ,west1 ,north-west1 ,north ,west by ,north1 ,north ,north-west1 ,north by ,west4 ,they are indicated by their initials as ,n4 ,n4 ,w41 ,north ,north-west1 ,n4 by ,w41 ,north by ,west4 ,compass1 ,spirit4 ,a form of mariner's compass4 ,the bowl or case is hermetically sealed and filled with alcohol or other nonfreezing liquid4 ,the compass card is made with hollow compartments so as nearly to float4 ,in this way the friction of the pivot or point of support is greatly diminished1 and the compass is far more sensitive4 ,compass1 ,surveyor's4 ,a species of theodolite2 a telescope with collimation lines1 mounted above a compass1 so as to be applicable for magnetic surveys4 ,its use is to be discouraged on account of the inaccuracy and changes in declination of the magnetic needle4 #add ,,standard ,,electrical ,,dictionary4 ,compensating ,resistances4 ,in using a galvanometer shunt the total resistance of the circuit is diminished so that in some cases too much current flows through it2 in such case additional resistance1 termed as above1 is sometimes introduced in series4 ,the shunt in parallel with the galvanometer is thus compensated for1 and the experimental or trial circuit does not take too much current4 ,complementary ,distribution4 ,every distribution of electricity has somewhere a corresponding distribution1 exactly equal to it of opposite electricity2 the latter is the complimentary distribution to the first1 and the first distribution is also complimentary to it4 ,component4 ,a force may always be represented diagrammatically by a straight line1 terminating in an arrow-head to indicate the direction1 and of length to represent the intensity of the force4 ,the line may always be assumed to represent the diagonal of a parallelogram1 two of whose sides are represented by lines starting from the base of the arrow1 and of length fixed by the condition that the original force shall be the diagonal of the parallelogram of which they are two contiguous sides2 such lines are called components1 and actually represent forces into which the original force may always be resolved4 ,the components can have any direction4 ,thus the vertical component of a horizontal force is zero2 its horizontal component is equal to itself4 ,its #dej component is equal to the square root of one-half of its square4 ,condenser4 ,an appliance for storing up electrostatic charges3 it is also called a static accumulator4 ,the telegraphic condenser consists of a box packed full of sheets of tinfoil4 ,between every two sheets is a sheet of paraffined paper1 or of mica4 ,the alternate sheets of tinfoil are connected together1 and each set has its own binding post4 7,see ,accumulator1 ,electrostatic47 ,condenser1 ,sliding4 ,an apparatus representing a ,leyden jar whose coatings can be slid past each other4 ,this diminishes or increases the facing area1 and consequently in almost exactly similar ratio diminishes or increases the capacity of the condenser4 ,conductance4 ,the conducting power of a given mass of specified material of specified shape and connections4 ,conductance varies in cylindrical or prismatic conductors1 inversely as the length1 directly as the cross-section1 and with the conductivity of the material4 ,conductance is an attribute of any specified conductor1 and refers to its shape1 length and other factors4 ,conductivity is an attribute of any specified material without direct reference to its shape1 or other factors4 ,conduction4 ,the process or act of conducting a current4 #ade ,,standard ,,electrical ,,dictionary4 ,conductivity4 ,the relative power of conducting the electric current possessed by different substances4 ,a path for the current through the ether is opened by the presence of a body of proper quality1 and this quality1 probably correlated to opacity1 is termed conductivity4 ,there is no perfect conductor1 all offer some resistance1 q4 v41 and there is hardly any perfect non-conductor4 ,it is the reverse and reciprocal of resistance4 ,conductivity1 ,specific4 ,the reciprocal of specific resistance4 7,see ,resistance--,specific47 ,conductivity1 ,unit of4 ,the reciprocal of the ohm2 it is a more logical unit1 but has never been generally adopted2 as a name the title mho 7or ohm written backwards7 has been suggested by ,sir ,william ,thomson1 and provisionally adopted4 ,conductivity1 ,variable4 ,the conductivity for electric currents of conductors varies with their temperature1 with varying magnetization1 tension1 torsion and compression4 ,conductor4 ,in electricity1 anything that permits the passage of an electric current4 ,any disturbance in the ether takes the form of waves because the ether has restitutive force or elasticity4 ,in a conductor1 on the other hand1 this force is wanting2 it opens a path through the ether and a disturbance advances through it from end to end with a wave front1 but with no succession of waves4 ,this advance is the beginning of what is termed a current4 ,it is1 by some theorists1 attributed to impulses given at all points along the conductor through the surrounding ether1 so that a current is not merely due to an end thrust4 ,if ether waves preclude a current on account of their restitutive force1 ether waves cannot be maintained in a conductor1 hence conductors should be opaque to light1 for the latter is due to ether waves4 ,this is one of the more practical every day facts brought out in ,clerk ,maxwell's electromagnetic theory of light4 ,the term conductor is a relative one1 as except a vacuum there is probably no substance that has not some conducting power4 ,for relative conducting power1 tables of conductivity1 q4 v41 should be consulted4 ,the metals beginning with silver are the best conductors1 glass is one of the worst4 ,transcriber's note3 ,see ether for contemporary comments on this now discarded concept4 ,conductor1 ,anti-,induction4 ,a current conductor arranged to avoid induction from other lines4 ,many kinds have been invented and made the subject of patents4 ,a fair approximation may be attained by using a through metallic circuit and twisting the wires composing it around each other4 ,sometimes concentric conductors1 one a wire and the other a tube1 are used1 insulated1 one acting as return circuit for the other4 ,conductor1 ,conical4 ,a prime conductor of approximately conical shape1 but rounded on all points and angles4 ,its potential is highest at the point4 #adf ,,standard ,,electrical ,,dictionary4 ,conductor1 ,imbricated4 ,a conductor used in dynamo armatures for avoiding eddy currents1 made by twisting together two or more strips of copper4 ,conductor1 ,prime4 ,a body often cylindrical or spherical in shape1 in any case with no points or angles1 but rounded everywhere1 whose surface1 if the conductor itself is not metallic1 is made conducting by tinfoil or gold leaf pasted over it4 ,it is supported on an insulating stand and is used to collect or receive and retain static charges of electricity4 ,conductors1 ,equivalent4 ,conductors of identical resistance4 ,the quotient of the length divided by the product of the conductivity and cross-section must be the same in each1 if each is of uniform diameter4 ,conjugate4 adj4 ,conjugate coils or conductors are coils placed in such relation that the lines of force established by one do not pass through the coils of the other4 ,hence variations of current in one produce no induced currents in the other4 ,connect4 v4 ,to bring two ends of a conductor together1 or to bring one end of a conductor in connection with another1 or in any way to bring about an electrical connection4 ,connector4 ,a sleeve with screws or other equivalent device for securing the ends of wires in electrical contact4 ,a binding-post1 q4 v41 is an example4 ,sometimes wire spring-catches are used1 the general idea being a device that enables wires to be connected or released at will without breaking off or marring their ends4 ,the latter troubles result from twisting wires together4 ,consequent ,poles4 ,a bar magnet is often purposely or accidentally magnetized so as to have both ends of the same polarity1 and the center of opposite polarity4 ,the center is said to comprise two consequent poles4 7,see ,magnet1 ,anomalous47 ,conservation of ,electricity4 ,as every charge of electricity has its equal and opposite charge somewhere1 near or far1 more or less distributed1 the sum of negative is equal always to the sum of positive electrical charges4 ,for this doctrine the above title was proposed by ,lippman4 ,contact ,breaker4 ,any contrivance for closing a circuit1 and generally for opening and closing in quick succession4 ,an old and primitive form consisted of a very coarsely cut file4 ,this was connected to one terminal1 and the other terminal was drawn over its face1 making and breaking contact as it jumped from tooth to tooth4 7,see ,circuit ,breaker--do4 ,automatic1 etc4--do4 ,wheel-do4 ,pendulum47 #adg ,,standard ,,electrical ,,dictionary4 ,contact1 ,electric4 ,a contact between two conductors1 such that a current can flow through it4 ,it may be brought about by simple touch or impact between the ends or terminals of a circuit1 sometimes called a dotting contact1 or by a sliding or rubbing of one terminal on another1 or by a wheel rolling on a surface1 the wheel and surface representing the two terminals4 ,there are various descriptions of contact1 whose names are self-explanatory4 ,the term is applied to telegraph line faults also1 and under this1 includes different descriptions of contact with neighboring lines1 or with the earth4 ,contact ,electricity4 ,when two dissimilar substances are touched they assume different electric potentials4 ,if conductors1 their entire surfaces are affected2 if dielectrics1 only the surfaces which touch each other4 7,see ,contact ,theory47 ,contact ,faults4 ,a class of faults often called contacts1 due to contact of the conductor of a circuit with another conductor4 ,a full or metallic contact is where practically perfect contact is established2 a partial contact and intermittent contact are self-explanatory4 ,contact ,point4 ,a point1 pin or stud1 often of platinum1 arranged to come in contact with a contact spring1 q4 v41 or another contact point or surface1 under any determined conditions4 ,contact ,potential ,difference4 ,the potential difference established by the contact of two dissimilar substances according to the contact theory1 q4 v4 ,contact ,series4 ,an arrangement or tabulation of substances in pairs1 each intermediate substance appearing in two pairs1 as the last member of the first1 and first member of the succeeding pair1 with the statement of the potential difference due to their contact1 the positively electrified substance coming first4 ,the following table of some contact potentials is due to ,ayrton and ,perry3 ,,contact ,,series4 ,difference of ,potential in ,volts4 ,zinc--,lead 4#baj ,lead--,tin 4#jfi ,tin--,iron 4#cac ,iron--,copper 4#adf ,copper--,platinum 4#bch ,platinum-,carbon 4#aac ,the sum of these differences is #a4jhi1 which is the contact potential between zinc and carbon4 ,volta's ,law refers to this and states that-- ,the difference of potential produced by the contact of any two substances is equal to the sum of the differences of potentials between the intervening substances in the contact series4 ,it is to be remarked that the law should no longer be restricted to or stated only for metals4 #adh ,,standard ,,electrical ,,dictionary4 ,contact-spring4 ,a spring connected to one lead of an electric circuit1 arranged to press against another spring1 or contact point1 q4 v41 under any conditions determined by the construction of the apparatus4 7,see ,bell1 ,electric--,coil1 ,induction47 ,contact ,theory4 ,a theory devised to explain electrification1 the charging of bodies by friction1 or rubbing1 and the production of current by the voltaic battery4 ,it holds that two bodies1 by mere contact become oppositely electrified4 ,if such contact is increased in extent by rubbing together1 the intensity of their electrification is increased4 ,this electrification is accounted for by the assumption of different kinetic energy1 or energy of molecular motion1 possessed by the two bodies2 there being a loss and gain of energy1 on the two sides respectively1 the opposite electrifications are the result4 ,then when separated1 the two bodies come apart oppositely electrified4 ,the above accounts for the frictional production of electricity4 ,in the voltaic battery1 a separation of the atoms of hydrogen and oxygen1 and their consolidation into molecules occurs1 and to such separation and the opposite electrification of the electrodes by the oxygen and hydrogen1 the current is attributed1 because the hydrogen goes to one electrode1 and the oxygen to the other1 each giving up or sharing its own charge with the electrodes to which it goes4 ,if zinc is touched to copper1 the zinc is positively and the copper negatively electrified4 ,in the separation of hydrogen and oxygen1 the hydrogen is positively and the oxygen negatively electrified4 ,in the battery1 the current is due to the higher contact difference of oxygen and hydrogen compared to that between zinc and copper4 ,it will be seen that the two contact actions in a battery work against each other1 and that the current is due to a differential contact action4 ,the zinc in a battery is electrified negatively because the negative electrification of the oxygen is greater in amount than its own positive electrification due to contact with the copper4 ,contractures4 ,a muscular spasm or tetanus due to the passage of a current of electricity2 a term in electro-therapeutics4 ,controlling ,field4 ,the magnetic or electro-magnetic field1 which is used in galvanometers to control the magnetic needle1 tending to restore it to a definite position whenever it is turned therefrom4 ,it may be the earth's field or one artificially produced4 ,controlling ,force4 ,in galvanometers and similar instruments1 the force used to bring the needle or indicator back to zero4 7,see ,controlling ,field--,electro-,magnetic ,control--,gravity ,control--,magnetic ,control--,spring ,control47 #adi ,,standard ,,electrical ,,dictionary4 ,convection1 ,electric4 ,the production of blasts or currents of air 7convection streams7 from points connected to statically charged conductors4 ,the term is sometimes applied to electric convection of heat4 7,see ,convection of ,heat1 ,electric47 ,convection1 ,electrolytic4 ,the resistance of acidulated water as a true conductor is known to be very1 almost immeasurably1 high4 ,as an electrolytic1 its resistance is very much lower4 ,hence the current produced between immersed electrodes is theoretically almost null1 unless the difference of potential between them is high enough to decompose the liquid4 ,yet a feeble current too great for a true conduction current is sometimes observed when two electrodes with potential difference too low to cause decomposition are immersed in it4 ,such a current is termed an electrolytic convection current4 ,it is supposed to be due to various causes4 ,some attribute it to the presence of free oxygen from the air1 dissolved in the water with which the hydrogen combines4 ,others attribute it to the diffusion of the gases of decomposition in the solution2 others assume a partial polarization of the molecules without decomposition4 ,other theories are given1 all of which are unsatisfactory4 ,the term is due to ,helmholtz4 ,convection of ,heat1 ,electric4 ,the effect of a current upon the distribution of heat in an unevenly heated conductor4 ,in some1 such as copper1 the current tends to equalize the varying temperatures2 the convection is then said to be positive1 as comparable to that of water flowing through an unequally heated tube4 ,in others1 such as platinum or iron1 it is negative1 making the heated parts hotter1 and the cooler parts relatively cooler4 ,the effect of the electric current in affecting the distribution of heat in unequally heated metal 7,thomson's effect4 q4 v471 is sometimes so termed4 ,if a current passes through unequally heated iron it tends to increase the difference of temperature1 and the convection is negative2 in copper it tends to equalize the temperature1 and the convection is positive4 ,converter4 ,an induction coil used with the alternating current for changing potential difference and inversely therewith the available current4 ,they generally lower the potential1 and increase the current1 and are placed between the primary high potential system that connects the houses with the central station1 and the secondary low potential system within the houses4 ,a converter consists of a core of thin iron sheets1 wound with a fine primary coil of many convolutions1 and a coarse secondary coil of few convolutions4 ,the ratio of convolutions gives the ratio of maximum potential differences of their terminals between the primary and secondary coils4 ,the coil may be jacketed with iron to increase the permeance4 7,see ,alternating ,current ,system47 ,fig4 #aaj4 ,,ferranti',s ,,converter ,,or ,,transformer4 ,fig4 #aaa4 ,,swinburne',s ,,hedgehog ,,transformer4 #aej ,,standard ,,electrical ,,dictionary4 ,co-ordinates1 ,system of4 ,a system for indicating the position of points in space by reference to fixed lines1 intersecting at a determined and arbitrary point #j1 termed the origin of co-ordinates4 ,in plane rectangular co-ordinates two lines are drawn through the origin1 one horizontal1 termed the axis of abscissas1 or axis of ,x4 ,all distances measured parallel to it1 if unknown1 are indicated by x1 and are termed abscissas4 ,the other axis is vertical1 and is termed the axis of ordinates1 or axis of ,y4 ,all distances measured parallel to it1 if unknown1 are indicated by y and are termed ordinates4 ,thus by naming its abscissa and ordinate a point has its position with reference to the axes determined1 and by indicating the relation between a point1 line or curve1 and a system of abscissas and ordinates1 the properties of a line or curve can be expressed algebraically4 ,co-ordinates may also be inclined to each other at any other angles1 forming oblique co-ordinates2 relations may be expressed partly in angles referred to the origin as a centre1 giving polar co-ordinates4 ,for solid geometry or calculations in three dimensions1 a third axis1 or axis of ,z1 is used1 distances parallel to which if unknown are indicated by z4 ,fig4 #aab4 ,,axes ,,of ,,co-,,ordinates4 #aea ,,standard ,,electrical ,,dictionary4 ,cooling ,box4 ,in a hydroelectric machine1 q4 v41 a conduit or chest through which the steam passes on its way to the nozzles4 ,its object is to partially condense the steam so as to charge it with water vesicles whose friction against the sides of the nozzles produces the electrification 4 #aeb ,,standard ,,electrical ,,dictionary4 ,copper4 ,a metal2 one of the elements4 ,symbol1 ,cu2 atomic weight1 #fc4e2 equivalent1 #fc4e and #ca4ge2 valency1 #a and #b2 specific gravity1 #h4if4 ,it is a conductor of electricity1 whose conductivity is liable to vary greatly on account of impurities4 ,annealed4 ,hard drawn4 ,relative resistance 7,silver #a71 #a4jfc #a4jhf ,specific resistance1 #a4eih #a4fcd microhms4 ,resistance of a wire at #j ,c4 7#cb ,f471 ,annealed4 ,hard ,drawn4 7a7 #a foot long1 weighing #a grain1 4#bjda ohms 4#bjhc ohms4 7b7 #a foot long1 #a_/ajjj inch thick1 #i4fab #i4hca 7c7 #a meter long1 weighing #a gram1 4#adbd 4#adec 7d7 #a meter long1 #a millimeter thick1 4#jbjcd 4#jbjha microhm4 microhm4 ,resistance of #a inch cube at #j;,c4 7#cb ,f47 4#fbib 4#fdcc ,percentage of resistance change1 per #a ,c4 7#a4h ,f47 at about #bj ,c4 7#fh ,f47 #j4chh per cent4 ,electro-chemical ,equivalent 7,hydrogen 4#jaje7 ,cuprous 4#fffg ,cupric 4#cccd ,in electricity it has been very extensively used as the negative plate of voltaic batteries4 ,it has its most extensive application as conductors for all classes of electrical leads4 ,copper ,bath4 ,a solution of copper used for depositing the metal in the electroplating process4 ,for some metals1 such as zinc or iron1 which decompose copper sulphate solution1 special baths have to be used4 ,the regular bath for copper plating is the following3 ,to water acidulated with #h to #aj percent4 of sulphuric acid as much copper sulphate is added as it will take up at the ordinary temperature4 ,the saturated bath should have a density of #a4ba4 ,it is used cold and is kept in condition by the use of copper anodes1 or fresh crystals may be added from time to time4 ,for deposition on zinc1 iron1 tin and other metals more electropositive than copper1 the following baths may be used1 expressed in parts by weight3 ,tin ,iron and ,steel4 ,cast ,iron ,cold ,hot4 and ,zinc4 ,zinc4 ,sodium ,bisulphate1 #ejj #bjj #cjj #ajj ,potassium ,cyanide1 #ejj #gjj #ejj #gjj ,sodium ,carbonate1 #ajjj #ejj --- --- ,copper ,acetate1 #dge #ejj #cej #dej ,aqua ,ammoniae1 #cej #cjj #bjj #aej ,water1 #bejj #bejj #bejj #bejj ,these are due to ,roseleur4 #aec ,,standard ,,electrical ,,dictionary4 ,copper ,stripping ,bath4 ,there is generally no object in stripping copper from objects4 ,it can be done with any of the regular copper baths using the objects to be stripped as anode4 ,the danger of dissolving the base itself and thereby injuring the article and spoiling the bath is obvious4 ,cord ,adjuster4 ,a device for shortening or lengthening the flexible cord1 or flexible wire supplying the current1 and by which an incandescent lamp is suspended4 ,it often is merely a little block of wood perforated with two holes through which the wires pass1 and in which they are retained in any desired position by friction and their own stiffness4 ,fig4 #aac4 ,,flexible ,,cord ,,adjuster4 ,cord1 ,flexible4 ,a pair of flexible wire conductors1 insulated lightly1 twisted together and forming apparently a cord4 ,they are used for minor services1 such as single lamps and the like1 and are designated according to the service they perform1 such as battery cords1 dental cords 7for supplying dental apparatus7 and other titles4 ,core4 7a7 ,the conductor or conductors of an electric cable4 7,see ,cable ,core47 7b7 ,the iron mass1 generally central in an electro-magnet or armature1 around which the wire is coiled4 ,it acts by its high permeance to concentrate or multiply the lines of force1 thus maintaining a more intense field4 7,see ,armature--,magnet1 ,electro--,magnet1 ,field--,core1 ,laminated74 ,in converters or transformers 7,see ,converter7 it often surrounds the wire coils4 ,core-discs4 ,discs of thin wire1 for building up armature cores4 7,see ,laminated ,core47 ,the usual form of core is a cylinder4 ,a number of thin discs of iron are strung upon the central shaft and pressed firmly together by end nuts or keys4 ,this arrangement1 it will be seen1 gives a cylinder as basis for winding the wire on4 ,core-discs1 ,pierced4 ,core-discs for an armature of dynamo or motor1 which are pierced around the periphery4 ,tubes of insulating material pass through the peripheral holes1 and through these the conductors or windings are carried4 ,the conductors are thus embedded in a mass of iron and are protected from eddy currents1 and they act to reduce the reluctance of the air gaps4 ,from a mechanical point of view they are very good4 ,for voltages over #ajj they are not advised4 ,synonym--,perforated ,core-discs4 #aed ,,standard ,,electrical ,,dictionary4 ,core-discs1 ,segmental4 ,core-discs made in segments1 which are bolted together to form a complete disc or section of the core4 ,the plan is adopted principally on large cores4 ,the discs thus made up are placed together to form the core exactly as in the case of ordinary one piece discs4 ,fig4 #aad4 ,,pierced ,,or ,,perforated ,,core-,,disc4 ,core-discs1 ,toothed4 ,core-discs of an armature of a dynamo or motor1 which discs are cut into notches on the periphery4 ,these are put together to form the armature core1 with the notches corresponding so as to form a series of grooves in which the wire winding is laid4 ,this construction reduces the actual air-gaps1 and keeps the wires evenly spaced4 ,distance-pieces of box-wood1 m1 m1 are sometimes used to lead the wires at the ends of the armature4 ,fig4 #aae4 ,,toothed ,,core-,,disc4 ,core1 ,laminated4 ,a core of an armature1 induction coil or converter or other similar construction1 which is made up of plates insulated more or less perfectly from each other4 ,the object of lamination is to prevent the formation of ,foucault currents4 7,see ,currents1 ,foucault47 ,as insulation1 thin shellacked paper may be used1 or sometimes the superficial oxidation of the plates alone is relied on4 ,the plates1 in general1 are laid perpendicular to the principal convolutions of the wire1 or parallel to the lines of force4 ,the object is to break up currents1 and such currents are induced by the variation in intensity of the field of force1 and their direction is perpendicular to the lines of force1 or parallel to the inducing conductors4 ,a core built up of core discs is sometimes termed a tangentially laminated core4 ,made up of ribbon or wire wound coil fashion1 it is termed a radially laminated core4 #aee ,,standard ,,electrical ,,dictionary4 ,core ,ratio4 ,in a telegraph cable the ratio existing between the diameter of the conducting core and the insulator4 ,to get a ratio approximately accurate in practical calculations1 the diameter of the core is taken at #e per cent4 less than its actual diameter4 ,the calculations are those referring to the electric constants of the cable1 such as its static capacity and insulation resistance4 ,core1 ,ribbon4 ,for discoidal ring-shaped cores of armatures1 iron ribbon is often used to secure lamination and prevent ,foucault currents4 ,synonym--,tangentially ,laminated ,core4 ,core1 ,ring4 ,a core for a dynamo or motor armature1 which core forms a complete ring4 ,core1 ,stranded4 ,in an electric light cable1 a conducting core made up of a group of wires laid or twisted together4 ,core1 ,tubular4 ,tubes used as cores for electro-magnets4 ,for very small magnetizing power1 tubular cores are nearly as efficient as solid ones in straight magnets1 because the principal reluctance is due to the air-path4 ,on increasing the magnetization the tubular core becomes less efficient than the solid core1 as the reluctance of the air-path becomes proportionately of less importance in the circuit4 ,corpusants4 ,the sailors' name for ,st4 ,elmo's ,fire1 q4 v4 ,coulomb4 ,the practical unit of quantity of electricity4 ,it is the quantity passed by a current of one ampere intensity in one second4 ,it is equal to #a_/aj the ,c4 ,g4 ,s4 electro-magnetic unit of quantity1 and to #c1jjj1jjj1jjj ,c4 ,g4 ,s4 electrostatic units of quantity4 ,it corresponds to the decomposition of 4#jice milligrams of water1 or to the deposition of #a4aahae milligrams of silver4 ,transcriber's note3 ,a coulomb is approximately #f4bda;,e#ah electrons4 ,two point charges of one coulomb each1 one meter apart1 exerts a force of #ijj1jjj metric tons4 ,coulomb's ,laws of ,electrostatic ,attraction and ,repulsion4 #a4 ,the repulsions or attractions between two electrified bodies are in the inverse ratio of the squares of their distance4 #b4 ,the distance remaining the same1 the force of attraction or repulsion between two electrified bodies is directly as the product of the quantities of electricity with which they are charged4 #aef ,,standard ,,electrical ,,dictionary4 ,counter1 ,electric4 ,a device for registering electrically1 or by electro-magnetic machinery1 the revolutions of shafts1 or any other data or factors4 ,counter-electro-motive ,force4 ,a potential difference in a circuit opposed to the main potential difference1 and hence1 resisting the operation of the latter1 and diminishing the current which would be produced without it4 ,it appears in electric motors1 which1 to a certain extent1 operate as dynamos and reduce the effective electro-motive force that operates them4 ,it appears in the primary coils of induction coils1 and when the secondary circuit is open1 is almost equal to the main electro-motive force1 so that hardly any current can go through them under such conditions4 ,it appears in galvanic batteries1 when hydrogen accumulates on the copper plate1 and in other chemical reactions4 ,a secondary battery is charged by a current in the reverse direction to that which it would normally produce4 ,its own potential difference then appears as a counter-electro-motive force4 ,synonym--,back ,electro-motive ,force4 ,counter-electro-motive ,force of ,polarization4 ,to decompose a solution by electrolysis1 enough electro-motive force is required to overcome the energy of composition of the molecule decomposed4 ,a part of this takes the form of a counter-electromotive force1 one which1 for a greater or less time would maintain a current in the opposite direction if the original source of current were removed4 ,thus in the decomposition of water1 the electrodes become covered1 one with bubbles of oxygen1 the others with bubbles of hydrogen2 this creates a counter ,e4 ,m4 ,f4 of polarization4 ,in a secondary battery1 the working current may be defined as due to this cause4 ,synonym--,back ,electro-motive ,force of ,polarization4 ,couple4 ,two forces applied to different points of a straight line1 when opposed in direction or unequal in amount1 tend to cause rotation about a point intermediate between their points of application and lying on the straight line4 ,such a pair constitute a couple4 ,couple1 ,voltaic or ,galvanic4 ,the combination of two electrodes1 and a liquid or liquids1 the electrodes being immersed therein1 and being acted on differentially by the liquid or liquids4 ,the combination constitutes a source of electro-motive force and consequently of current4 ,it is the galvanic or voltaic cell or battery4 7,see ,battery1 ,voltaic--,contact ,theory--,electro-motive ,force--,electro-motive ,series47 ,coupling4 ,the joining of cells of a galvanic battery1 of dynamos or of other devices1 so as to produce different effects as desired4 #aeg ,,standard ,,electrical ,,dictionary ,couple1 ,astatic4 ,an astatic couple is a term sometimes applied to astatic needles1 q4v4 ,c4 ,p4 7a7 ,an abbreviation of or symbol for candle power1 q4 v4 7b7 ,an abbreviation of chemically pure4 ,it is used to indicate a high degree of purity of chemicals4 ,thus1 in a standard ,daniell battery1 the use of ,c4 ,p4 chemicals may be prescribed or advised4 ,crater4 ,the depression that forms in the positive carbon of a voltaic arc4 7,see ,arc1 ,voltaic47 ,creeping4 ,a phenomenon of capillarity1 often annoying in battery jars4 ,the solution1 by capillarity1 rises a little distance up the sides1 evaporates1 and as it dries more creeps up through it1 and to a point a little above it4 ,this action is repeated until a layer of the salts may form over the top of the vessel4 ,to avoid it1 paraffine is often applied to the edges of the cup1 or a layer of oil1 often linseed oil1 is poured on the battery solution1 ,crith4 ,the weight of a litre of hydrogen at #j ,c4 7#cb ,f471 and #gfj mm4 7#cj inches7 barometric pressure4 ,it is 4#jhif grams4 ,the molecular weight of any gas divided by #b and multiplied by the value of the crith1 gives the weight of a litre of the gas in question4 ,thus a litre of electrolytic gas1 a mixture of two molecules of hydrogen for one of oxygen1 with a mean molecular weight of #ab1 weighs 7#ab_/b7 99 4#jhif or 4#ecgf gram4 ,critical ,speed4 7a7 ,the speed of rotation at which a series dynamo begins to excite its own field4 7b7 ,in a compound wound dynamo1 the speed at which the same potential is generated with the full load being taken from the machine1 as would be generated on open circuit1 in which case the shunt coil is the only exciter4 ,the speed at which the dynamo is self-regulating4 7c7 ,in a dynamo the rate of speed when a small change in the speed of rotation produces a comparatively great change in the electro-motive force4 ,it corresponds to the same current 7the critical current7 in any given series dynamo4 ,cross4 7a7 ,a contact between two electric conductors2 qualified to express conditions as a weather cross1 due to rain1 a swinging cross when a wire swings against another1 etc4 7b7 vb4 ,to make such contact4 ,cross-,connecting ,board4 ,a special switch board used in telephone exchanges and central telegraph offices4 ,its function is1 by plugs and wires1 to connect the line wires with any desired section of the main switchboard4 ,the terminals of the lines as they enter the building are connected directly to the cross-connecting board4 #aeh ,,standard ,,electrical ,,dictionary4 ,cross ,connection4 ,a method of disposing of the effects of induction from neighboring circuits by alternately crossing the two wires of a metallic telephone circuit1 so that for equal intervals they lie to right and left1 or one above1 and one below4 ,transcriber's note3 ,also used to cancel the effect of variations in the ambient magnetic field1 such as solar activity4 ,crossing ,wires4 ,the cutting out of a defective section in a telegraph line1 by carrying two wires from each side of the defective section across to a neighboring conductor1 pressing it for the time into service and cutting the other wire if necessary4 ,cross-magnetizing ,effect4 ,a phase of armature interference4 ,the current in an armature of a dynamo or motor is such as to develop lines of force approximately at right angles to those of the field4 ,the net cross-magnetizing effect is such component of these lines1 as is at right angles to the lines produced by the field alone4 ,cross-over ,block4 ,a piece of porcelain or other material shaped to receive two wires which are to cross each other1 and hold them so that they cannot come in contact4 ,it is used in wiring buildings1 and similar purposes4 7,see ,cleat1 ,crossing47 ,cross ,talk4 ,on telephone circuits by induction or by contact with other wires sound effects of talking are sometimes received from other circuits2 such effects are termed cross talk4 ,crucible1 ,electric4 ,a crucible for melting difficultly fusible substances1 or for reducing ores1 etc41 by the electric arc produced within it4 ,sometimes the heating is due more to current incandescence than to the action of an arc4 ,fig4 #aaf4 ,,electric ,,furnace ,,or ,,crucible4 ,crystallization1 ,electric4 ,many substances under proper conditions take a crystalline form4 ,the great condition is the passage from the fluid into the solid state4 ,when such is brought about by electricity in any way1 the term electric crystallization may be applied to the phenomenon4 ,a solution of silver nitrate for instance1 decomposed by a current1 may give crystals of metallic silver4 #aei ,,standard ,,electrical ,,dictionary4 ,cup1 ,porous4 ,a cup used in two-fluid voltaic batteries to keep the solutions separate to some extent4 ,it forms a diaphragm through which diffusion inevitably takes place1 but which is considerably retarded1 while electrolysis and electrolytic convection take place freely through its walls4 ,as material1 unglazed pottery is very generally used4 ,in some batteries the cup is merely a receptacle for the solid depolarizer4 ,thus1 in the ,leclanch battery1 the cup contains the manganese dioxide and graphite in which the carbon electrode is embedded1 but does not separate two solutions1 as the battery only uses one4 ,nevertheless1 the composition of the solution outside and inside may vary1 but such variation is incidental only1 and not an essential of the operation4 ,current4 ,the adjustment1 or effects of a continuous attempt at readjustment of potential difference by a conductor1 q4 v41 connecting two points of different potential4 ,a charged particle or body placed in a field of force tends to move toward the oppositely charged end or portion of the field4 ,if a series of conducting particles or a conducting body are held so as to be unable to move1 then the charge of the field tends1 as it were1 to move through it1 and a current results4 ,it is really a redistribution of the field and as long as such redistribution continues a current exists4 ,a current is assumed to flow from a positive to a negative terminal2 as in the case of a battery1 the current in the outer circuit is assumed to flow from the carbon to the zinc plate1 and in the solution to continue from zinc to carbon4 ,as a memoria technica the zinc may be thought of as generating the current delivering it through the solution to the carbon1 whence it flows through the wire connecting them4 7,see ,ohm's ,law--,maxwell's ,theory of ,light--,conductor-,intensity47 ,transcriber's note3 ,supposing electric current to be the motion of positive charge causes no practical difficulty1 but the current is actually the 7slight7 motion of negative electrons4 ,current1 ,after4 ,a current produced by the animal tissue after it has been subjected to a current in the opposite direction for some time4 ,the tissue acts like a secondary battery4 ,the term is used in electro-therapeutics4 ,current1 ,alternating4 ,usually defined and spoken of as a current flowing alternately in opposite directions4 ,it may be considered as a succession of currents1 each of short duration and of direction opposite to that of its predecessor4 ,it is graphically represented by such a curve as shown in the cut4 ,the horizontal line may denote a zero current1 that is no current at all1 or may be taken to indicate zero electro-motive force4 ,the curve represents the current1 or the corresponding electro-motive forces4 ,the further from the horizontal line the greater is either1 and if above the line the direction is opposite to that corresponding to the positions below the line4 ,thus the current is alternately in opposite directions1 has periods of maximum intensity1 first in one and then in the opposite sense1 and between these1 passing from one direction to the other1 is of zero intensity4 ,it is obvious that the current may rise quickly in intensity and fall slowly1 or the reverse1 or may rise and fall irregularly4 ,all such phases may be shown by the curve1 and a curve drawn to correctly represent these variations is called the characteristic curve of such current4 ,it is immaterial whether the ordinates of the curve be taken as representing current strength or electromotive force4 ,if interpreted as representing electro-motive force1 the usual interpretation and best1 the ordinates above the line are taken as positive and those below as negative4 ,synonyms--,reversed ,current--,periodic ,currents4 ,fig4 #aag4 ,,characteristic ,,curve ,,of ,,alternating ,,current4 #afj ,,standard ,,electrical ,,dictionary4 ,current1 ,atomic4 ,a unit of current strength used in ,germany2 the strength of a current which will liberate in #bd hours 7#hf1djj seconds7 one gram of hydrogen gas1 in a water voltameter4 ,the atomic current is equal to #a4aaa amperes4 ,in telegraphic work the milliatom is used as a unit1 comparable to the milliampere4 ,the latter is now displacing it4 ,current1 ,charge4 ,if the external coatings of a charged and uncharged jar are placed in connection1 and if the inner coatings are now connected1 after separating them they are both found to be charged in the same manner4 ,in this process a current has been produced between the outside coatings and one between the inner ones1 to which ,dove has given the name ,charge ,current1 and which has all the properties of the ordinary discharge current4 7,ganot47 ,current1 ,circular4 ,a current passing through a circular conductor2 a current whose path is in the shape of a circle4 ,current1 ,commuted4 ,a current changed1 as regards direction or directions1 by a commutator1 q4 v41 or its equivalent4 ,current1 ,constant4 ,an unvarying current4 ,a constant current system is one maintaining such a current4 ,in electric series1 incandescent lighting1 a constant current is employed1 and the system is termed as above4 ,in arc lighting systems1 the constant current series arrangement is almost universal4 #afa ,,standard ,,electrical ,,dictionary4 ,current1 ,continuous4 ,a current of one direction only2 the reverse of an alternating current4 7,see ,current1 ,alternating47 ,current1 ,critical4 ,the current produced by a dynamo at its critical speed2 at that speed when a slight difference in speed produces a great difference in electro-motive force4 ,on the characteristic curve it corresponds to the point where the curve bends sharply1 and where the electro-motive force is about two-thirds its maximum4 ,current1 ,daniell_/,u4,s4 1 ,daniell_/,siemens' ,unit4 ,a unit of current strength used in ,germany4 ,it is the strength of a current produced by one ,daniell cell in a circuit of the resistance of one ,siemens' unit4 ,the current deposits #a4ch grams of copper per hour4 ,it is equal to #a4af amperes4 ,current1 ,demarcation4 ,in electro-therapeutics1 a current which can be taken from an injured muscle1 the injured portion acting electro-negatively toward the uninjured portion4 ,current ,density4 ,the current intensity per unit of cross-sectional area of the conductor4 ,the expression is more generally used for electrolytic conduction1 where the current-density is referred to the mean facing areas of the electrodes1 or else to the facing area of the cathode only4 ,the quality of the deposited metal is intimately related to the current density4 7,see ,burning47 ,proper ,current ,density for ,electroplating ,amperes ,per ,square ,foot of ,cathode4--7,urquhart47 ,copper1 ,acid ,bath4 #e4j to #aj4j ,cyanide ,bath1 #c4j #e4j ,silver1 ,double ,cyanide1 #b4j #e4j ,gold1 ,chloride dissolved in ,potassium ,cyanide1 #a4j #b4j ,nickel1 ,double ,sulphate1 #f4f #h4j ,brass1 ,cyanide1 #b4j #c4j ,current1 ,diacritical4 ,a current1 which1 passing through a helix surrounding an iron core1 brings it to one-half its magnetic saturation1 q4 v4 ,current1 ,diaphragm4 ,if a liquid is forced through a diaphragm1 a potential difference between the liquid on opposite sides of the diaphragm is maintained4 ,electrodes or terminals of platinum may be immersed in the liquid1 and a continuous current1 termed a diaphragm current1 may be taken as long as the liquid is forced through the diaphragm4 ,the potential difference is proportional to the pressure1 and also depends on the nature of the diaphragm and on the liquid4 #afb ,,standard ,,electrical ,,dictionary4 ,current1 ,direct4 ,a current of unvarying direction1 as distinguished from an alternating current4 ,it may be pulsatory or intermittent in character1 but must be of constant direction4 ,current1 ,direct ,induced4 ,on breaking a circuit1 if it is susceptible of exercising self-induction1 q4 v41 an extra current1 in the direction of the original is induced1 which is called direct because in the same direction as the original4 ,the same is produced by a current in one circuit upon a parallel one altogether separated from it4 7,see ,induction1 ,electro-,magnetic-,current1 ,extra47 ,synonym--,break ,induced ,current4 ,current1 ,direction of4 ,the assumed direction of a current is from positively charged electrode to negatively charged one2 in a galvanic battery from the carbon or copper plate through the outer circuit to the zinc plate and back through the electrolyte to the carbon or copper plate4 7,see ,current47 ,transcriber's note3 ,current is caused by the motion of negative electrons1 from the negative pole to the positive4 ,the electron was discovered five years after this publication4 ,current1 ,displacement4 ,the movement or current of electricity taking place in a dielectric during displacement4 ,it is theoretical only and can only be assumed to be of infinitely short duration4 7,see ,displacement1 ,electric47 ,currents1 ,eddy ,displacement4 ,the analogues of ,foucault currents1 hypothetically produced in the mass of a dielectric by the separation of the electricity or by its electrification4 7,see ,displacement47 ,current1 ,extra4 ,when a circuit is suddenly opened or closed a current of very brief duration1 in the first case in the same direction1 in the other case in the opposite direction1 is produced1 which exceeds the ordinary current in intensity4 ,a high potential difference is produced for an instant only4 ,these are called extra currents4 ,as they are produced by electro-magnetic induction1 anything which strengthens the field of force increases the potential difference to which they are due4 ,thus the wire may be wound in a coil around an iron core1 in which case the extra currents may be very strong4 7,see ,induction1 ,self-,coil1 ,spark47 ,current1 ,faradic4 ,a term in medical electricity for the induced or secondary alternating current1 produced by comparatively high electro-motive force1 such as given by an induction coil or magneto-generator1 as distinguished from the regular battery current4 #afc ,,standard ,,electrical ,,dictionary4 ,current1 ,foucault4 ,a current produced in solid conductors1 and which is converted into heat 7,ganot74 ,these currents are produced by moving the conductors through a field1 or by altering the strength of a field in which they are contained4 ,they are the source of much loss of energy and other derangement in dynamos and motors1 and to avoid them the armature cores are laminated1 the plane of the laminations being parallel to the lines of force4 7,see ,core1 ,laminated47 ,the presence of ,foucault currents1 if of long duration1 is shown by the heating of the metal in which they are produced4 ,in dynamo armatures they are produced sometimes in the metal of the windings1 especially if the latter are of large diameter4 ,synonyms--,eddy ,currents--,local ,currents--,parasitical ,currents4 ,current1 ,franklinic4 ,in electro-therapeutics the current produced by a frictional electric machine4 ,current1 ,induced4 ,the current produced in a conductor by varying the conditions of a field of force in which it is placed2 a current produced by induction4 ,current ,induction4 ,induction by one current on another or by a portion of a current on another portion of itself4 7,see ,induction47 ,current ,intensity4 ,current strength1 dependent on or defined by the quantity of electricity passed by such current in a given time4 ,the practical unit of current intensity is the ampere1 equal to one coulomb of quantity per second of time4 ,current1 ,inverse ,induced4 ,the current induced in a conductor1 when in a parallel conductor or in one having a parallel component a current is started1 or is increased in strength4 ,it is opposite in direction to the inducing current and hence is termed inverse4 7,see ,induction1 ,electro-magnetic47 ,the parallel conductors may be in one circuit or in two separate circuits4 ,synonyms--,make-induced ,current--,reverse-induced ,current4 ,current1 ,jacobi's ,unit of4 ,a current which will liberate one cubic centimeter of mixed gases 7hydrogen and oxygen7 in a water voltameter per minute1 the gases being measured at #j ,c4 7#cb ,f47 and #gfj mm4 7#bi4ib inches7 barometric pressure4 ,it is equal to 4#jifa ampere4 ,current1 ,joint4 ,the current given by several sources acting together4 ,properly1 it should be restricted to sources connected in series1 thus if two battery cells are connected in series the current they maintain is their joint current4 ,current1 ,linear4 ,a current passing through a straight conductor2 a current whose path follows a straight line4 #afd ,,standard ,,electrical ,,dictionary4 ,current1 ,make and ,break4 ,a succession of currents of short duration1 separated by absolute cessation of current4 ,such current is produced by a telegraph key1 or by a microphone badly adjusted1 so that the circuit is broken at intervals4 ,the ,u4 ,s4 ,courts have virtually decided that the telephone operates by the undulatory currents1 and not by a make and break current4 ,many attempts have been made to produce a telephone operating by a demonstrable make and break current1 on account of the above distinction1 in hopes of producing a telephone outside of the scope of the ,bell telephone patent4 ,transcriber's note3 ,contemporary long distance telephone service is digital1 as this item describes4 ,current-meter4 ,an apparatus for indicating the strength of current4 7,see ,ammeter47 ,current1 ,negative4 ,in the single needle telegraph system the current which deflects the needle to the left4 ,current1 ,nerve and ,muscle4 ,a current of electricity yielded by nerves or muscles4 ,under proper conditions feeble currents can be taken from nerves1 as the same can be taken from muscles4 ,current1 ,opposed4 ,the current given by two or more sources connected in opposition to each other4 ,thus a two volt and a one volt battery may be connected in opposition1 giving a net voltage of only one volt1 and a current due to such net voltage4 ,current1 ,partial4 ,a divided or branch current4 ,a current which goes through a single conductor to a point where one or more other conductors join it in parallel1 and then divides itself between the several conductors1 which must join further on1 produces partial currents4 ,it produces as many partial currents as the conductors among which it divides4 ,the point of division is termed the point of derivation4 ,synonym--,derived ,current4 ,current1 ,polarizing4 ,in electro-therapeutics1 a constant current4 ,current1 ,positive4 ,in the single needle telegraph system the current which deflects the needle to the right4 ,current1 ,pulsatory4 ,a current of constant direction1 but whose strength is constantly varying1 so that it is a series of pulsations of current instead of a steady flow4 ,current1 ,rectified4 ,a typical alternating current is represented by a sine curve1 whose undulations extend above and below the zero line4 ,if by a simple two member commutator the currents are caused to go in one direction1 in place of the sine curve a series of short convex curves following one another and all the same side of the zero line results4 ,the currents all in the same direction1 become what is known as a pulsating current4 ,synonym--,redressed ,current4 #afe ,,standard ,,electrical ,,dictionary4 ,current1 ,rectilinear4 ,a current flowing through a rectilinear conductor4 ,the action of currents depending on their distance from the points where they act1 their contour is a controlling factor4 ,this contour is determined by the conductors through which they flow4 ,current ,reverser4 ,a switch or other contrivance for reversing the direction of a current in a conductor4 ,currents1 ,amprian4 ,the currents of electricity assumed by ,ampere's theory to circulate around a magnet4 ,as they represent the maintenance of a current or of currents without the expenditure of energy they are often assumed to be of molecular dimensions4 ,as they all go in the same sense of rotation and are parallel to each other the result is the same as if a single set of currents circulated around the body of the magnet4 ,more will be found on this subject under ,magnetism4 ,the ,amprian currents are purely hypothetical and are predicated on the existence of a field of force about a permanent magnet4 7,see ,magnetism1 ,ampre's ,theory of47 ,if the observer faces the north pole of a magnet the ,amprian currents are assumed to go in the direction opposite to that of a watch1 and the reverse for the south pole4 ,figs4 #aah-aai ,,direction ,,of ,,amp,,rian ,,currents4 ,currents1 ,angular4 ,currents passing through conductors which form an angle with each other4 ,currents1 ,angular1 ,laws of4 #a4 ,two rectilinear currents1 the directions of which form an angle with each other1 attract one another when both approach to or recede from the apex of the angle4 #b4 ,they repel one another1 if one approaches and the other recedes from the apex of the angle4 #aff ,,standard ,,electrical ,,dictionary ,currents1 ,earth4 ,in long telegraph lines having terminal grounds or connected to earth only at their ends1 potential differences are sometimes observed that are sufficient to interfere with their working and which1 of course1 can produce currents4 ,these are termed earth-currents4 ,it will be noted that they exist in the wire1 not in the earth4 ,they may be of #dj milliamperes strength1 quite enough to work a telegraph line without any battery4 ,lines running ,n4 ,e4 and ,s4 ,w4 are most affected2 those running ,n4,w4 and ,s4 ,e4 very much less so4 ,these currents only exist in lines grounded at both ends1 and appear in underground wires4 ,hence they are not attributable to atmospheric electricity4 ,according to ,wilde they are the primary cause of magnetic storms1 q4 v41 but not of the periodical changes in the magnetic elements4 7,see ,magnetic ,elements47 ,synonym--,natural ,currents4 ,current1 ,secondary4 7a7 ,a current induced in one conductor by a variation in the current in a neighboring one2 the current produced in the secondary circuit of an induction coil or alternating current converter4 7b7 ,the current given by a secondary battery4 ,this terminology is not to be recommended4 ,current1 ,secretion4 ,in electro-therapeutics1 a current due to stimulation of the secretory nerves4 ,current ,sheet4 7a7 ,if two terminals of an active circuit are connected to two points of a thin metallic plate the current spreads over or occupies practically a considerable area of such plate1 and this portion of the current is a current sheet4 ,the general contour of the current sheet can be laid out in lines of flux4 ,such lines resemble lines of force4 ,like the latter1 they are purely an assumption1 as the current is not in any sense composed of lines4 7b7 ,a condition of current theoretically brought about by the ,amprian currents in a magnet4 ,each molecule having its own current1 the contiguous portions of the molecules counteract each other and give a resultant zero current4 ,all that remains is the outer sheet of electric current that surrounds the whole4 ,current1 ,sinuous4 ,a current passing through a sinuous conductor4 ,currents1 ,multiphase4 ,a term applied to groups of currents of alternating type which constantly differ from each other by a constant proportion of periods of alternation4 ,they are produced on a single dynamo1 the winding being so contrived that two1 three or more currents differing a constant amount in phase are collected from corresponding contact rings4 ,there are virtually as many windings on the armature as there are currents to be produced4 ,separate conductors for the currents must be used throughout4 ,synonyms--,polyphase ,currents--,rotatory ,currents4 #afg ,,standard ,,electrical ,,dictionary4 ,currents of ,motion4 ,in electro-therapeutics1 the currents produced in living muscle or nerves after sudden contraction or relaxation4 ,currents of ,rest4 ,in electro-therapeutics1 the currents traversing muscular or nervous tissue when at rest4 ,their existence is disputed4 ,currents1 ,orders of4 ,an intermittent current passing through a conductor will induce secondary alternating currents in a closed circuit near it4 ,this secondary current will induce a tertiary current in a third closed circuit near it1 and so on4 ,the induced currents are termed as of the first1 second1 third and other orders4 ,the experiment is carried out by ,henry's coils4 7,see ,coils1 ,henry's47 ,currents1 ,thermo-electric4 ,these currents1 as produced from existing thermo-electric batteries1 are generated by low potential1 and are of great constancy4 ,the opposite junctions of the plates can be kept at constant temperatures1 as by melting ice and condensing steam1 so that an identical current can be reproduced at will from a thermopile4 ,thermo-electric currents were used by ,ohm in establishing his law4 7,see ,ohm's ,law47 ,current1 ,swelling4 ,in electro-therapeutics1 a current gradually increasing in strength4 ,current1 ,undulatory4 ,a current varying in strength without any abrupt transition from action to inaction1 as in the make and break current4 ,the current may be continually changing in direction 7see ,current1 ,alternating71 and hence1 of necessity1 may pass through stages of zero intensity1 but such transition must be by a graduation1 not by an abrupt transition4 ,such current may be represented by a curve1 such as the curve of sines4 ,it is evident that the current may pass through the zero point as it crosses the line or changes direction without being a make and break current4 ,when such a current does alternate in direction it is sometimes called a shuttle current4 ,the ordinary commercial telephone current and the alternating current is of this type4 7,see ,current1 ,make and ,break47 ,current1 ,unit4 ,unit current is one which in a wire of unit length1 bent so as to form an arc of a circle of unit length of radius1 would act upon a unit pole 7see ,magnetic ,pole1 ,unit17 at the center of the circle with unit force4 ,unit length is the centimeter2 unit force is the dyne4 ,transcriber's note3 ,the ,,si definition of an ampere3 ,a current in two straight parallel conductors of infinite length and negligible cross-section1 #a metre apart in vacuum1 would produce a force equal to #b;,e-#g newton per metre of length4 #afh ,,standard ,,electrical ,,dictionary4 ,current1 ,wattless4 ,whenever there is a great difference in phase in an alternating current dynamo between volts and current1 the true watts are much less than the product of the virtual volts and amperes1 because the the watts are obtained by multiplying the product of the virtual volts and amperes by the cosine of the angle of lag 7or lead74 ,any alternating current may be resolved into two components in quadrature with each other1 one in phase with the volts1 the other in quadrature therewith1 the former is termed by ,s4 ,p4 ,thompson the ,working ,current1 the latter the ,wattless ,current4 ,the greater the angle of lag the greater will be the wattless current4 ,curve1 ,arrival4 ,a curve representing the rate of rise of intensity of current at the end of a long conductor when the circuit has been closed at the other end4 ,in the ,atlantic cable1 for instance1 it would require about #ajh seconds for the current at the distant end to attain #i_/aj of its full value4 ,the curve is drawn with its abscissa representing time and its ordinates current strength4 ,curve1 ,characteristic4 ,a curve indicating1 graphically1 the relations between any two factors1 which are interdependent1 or which vary simultaneously4 ,thus in a dynamo1 the voltage increases with the speed of rotation1 and a characteristic curve may be based on the relations between the speed of rotation and voltage developed4 ,the current produced by a dynamo varies with the electro-motive force1 and a curve can express the relations between the electro-motive force and the current produced4 ,a characteristic curve is usually laid out by rectangular co-ordinates 7see ,co-ordinates74 ,two lines are drawn at right angles to each other1 one vertical1 and the other horizontal4 ,one set of data are marked off on the horizontal line1 say one ampere1 two amperes1 and so on1 in the case of a dynamo's characteristic curve4 ,for each amperage of current there is a corresponding voltage in the circuit4 ,therefore on each ampere mark a vertical is erected1 and on that the voltage corresponding to such amperage is laid off4 ,this gives a series of points1 and these points may be connected by a curve4 ,such curve will be a characteristic curve4 ,the more usual way of laying out a curve is to work directly upon the two axes4 ,on one is laid off the series of values of one set of data2 on the other the corresponding series of values of the other dependent data4 ,vertical lines or ordinates1 q4 v41 are erected on the horizontal line or axis of abscissas at the points laid off2 horizontal lines or abscissas1 q4 v41 are drawn from the points laid off on the vertical line or axis of ordinates4 ,the characteristic curve is determined by the intersections of each corresponding pair of abscissa and ordinate4 #afi ,,standard ,,electrical ,,dictionary4 ,variations exist in characteristic curve methods4 ,thus to get the characteristic of a commutator1 radial lines may be drawn from a circle representing its perimeter4 ,such lines may be of length proportional to the voltage developed on the commutator at the points whence the lines start4 ,a cut giving an example of such a curve is given in ,fig4 #abe4 7,see ,curve of ,distribution of ,potential in ,armature47 ,there is nothing absolute in the use of ordinates or abscissas4 ,they may be interchanged4 ,ordinarily voltages are laid off as ordinates1 but the practise may be reversed4 ,the same liberty holds good for all characteristic curves4 ,custom1 however1 should be followed4 ,synonym--,characteristic4 ,fig4 #abj4 ,,characteristic ,,curve ,,of ,a ,,dynamo ,,with ,,horse ,,power ,,curves4 ,curve1 ,characteristic1 of ,converter4 ,the characteristic curve of the secondary circuit of an alternating current converter4 ,it gives by the usual methods 7see ,curve1 ,characteristic17 the relations between the electro-motive force and the current in the secondary circuit at a fixed resistance4 ,if connected in parallel a constant electro-motive force is maintained1 and the curve is virtually a straight line4 ,if connected in series an elliptical curve is produced4 #agj ,,standard ,,electrical ,,dictionary4 ,curve1 ,charging4 ,in secondary battery manipulation1 a curve indicating the increase of voltage as the charging is prolonged4 ,the rise in voltage with the duration of the charging current is not uniform4 ,in one case1 shown in the cut1 there was a brief rapid rise of about #j4a volt2 then a long slow rise for #j4ae volt2 then a more rapid rise for nearly #j4dj volt1 and then the curve became a horizontal line indicating a cessation of increase of voltage4 ,the charging rate should be constant4 ,the horizontal line is laid off in hours1 the vertical in volts1 so that the time is represented by abscissas and the voltage by ordinates of the curve4 ,fig4 #aba4 ,,charging ,,curve ,,of ,a ,,secondary ,,battery4 ,curve1 ,discharging4 ,a characteristic curve of a storage battery1 indicating the fall in voltage with hours of discharge4 ,the volts may be laid off on the axis of ordinates1 and the hours of discharging on the axis of abscissas4 ,to give it meaning the rate of discharge must be constant4 ,curve1 ,electro-motive ,force4 ,a characteristic curve of a dynamo4 ,it expresses the relation between its entire electromotive force1 as calculated by ,ohm's ,law1 and the current intensities corresponding thereto4 ,to obtain the data the dynamo is driven with different resistances in the external circuit and the current is measured for each resistance4 ,this gives the amperes4 ,the total resistance of the circuit1 including that of the dynamo1 is known4 ,by ,ohm's ,law the electro-motive force in volts is obtained for each case by multiplying the total resistance of the circuit in ohms by the amperes of current forced through such resistance4 ,taking the voltages thus calculated for ordinates and the corresponding amperages for abscissas the curve is plotted4 ,an example is shown in the cut4 #aga ,,standard ,,electrical ,,dictionary4 ,curve1 ,external ,characteristic4 ,a characteristic curve of a dynamo1 corresponding to the electro-motive force curve1 except that the ordinates represent the voltages of the external circuit1 the voltages as taken directly from the terminals of the machine1 instead of the total electro-motive force of the circuit4 ,the dynamo is run at constant speed4 ,the resistance of the external circuit is varied4 ,the voltages at the terminals of the machine and the amperages of current corresponding thereto are determined4 ,using the voltages thus determined as ordinates and the corresponding amperages as abscissas the external characteristic curve is plotted4 ,this curve can be mechanically produced4 ,a pencil may be moved against a constant force by two electro-magnets pulling at right angles to each other4 ,one must be excited by the main current of the machine1 the other by a shunt current from the terminals of the machine4 ,the point of the pencil will describe the curve4 ,fig4 #abb4 ,,characteristic ,,curve ,,of ,a ,,dynamo4 ,curve1 ,horse ,power4 ,curves indicating electric horse power4 ,they are laid out with co-ordinates1 volts being laid off on the axis of ordinates1 and amperes on the axis of abscissas generally4 ,the curves are drawn through points where the product of amperes by volts equals #gdf4 ,on the same diagram #a1 #b1 #c 4444 and any other horse powers can be plotted if within the limits4 ,see ,fig4 #abj4 ,curve1 ,isochasmen4 ,a line drawn on the map of the earth's surface indicating the locus of equal frequency of auroras4 #agb ,,standard ,,electrical ,,dictionary4 ,curve1 ,life4 ,a characteristic curve showing the relations between the durability and conditions affecting the same in any appliance4 ,it is used most for incandescent lamps4 ,the hours of burning before failure give ordinates1 and the rates of burning1 expressed indirectly in volts or in candle-power1 give abscissas4 ,for each voltage or for each candle-power an average duration is deducible from experience1 so that two dependent sets of data are obtained for the construction of the curve4 ,curve1 ,load4 ,a characteristic curve of a dynamo1 expressing the relation between its voltage and the amount of excitation under a definite condition of ampere load1 at a constant speed4 ,the ordinates represent voltage1 the abscissas ampere turns in the field1 and the curves may be constructed for a flow of #j1 #ej1 #ajj1 or 44 1 or any other number of amperes4 ,fig4 #abc4 ,,load ,,curves4 ,curve1 ,magnetization4 ,a characteristic curve of an electromagnet1 indicating the relation of magnetization to exciting current4 ,laying off on the axis of ordinates the quantities of magnetism evoked1 and the corresponding strengths of the exciting current on the axis of abscissas1 the curve can be plotted4 ,it first rises rapidly1 indicating a rapid increase of magnetization1 but grows nearly horizontal as the iron becomes more saturated4 ,the effect due to the coils alone1 or the effect produced in the absence of iron is a straight line1 because air does not change in permeability4 ,curve of ,distribution of ,potential in ,armature4 ,a characteristic curve indicating the distribution of potential difference between adjoining sections of the commutator of an armature in different positions all around it4 ,the potential differences are taken by a volt-meter or potential galvanometer1 connection with the armature being made by two small metal brushes1 held at a distance apart equal to the distance from centre to centre of two adjoining commutator bars4 ,the curve is laid out as if by polar co-ordinates extending around the cross-section of the commutator1 with the distances from the commutator surface to the curve proportional to the potential differences as determined by shifting the pair of brushes all around the commutator4 ,the above is ,s4 ,p4 ,thompson's method4 ,another method of ,w4 ,m4 ,mordey involves the use of a pilot brush4 7,see ,brush1 ,pilot47 ,otherwise the method is in general terms identical with the above4 #agc ,,standard ,,electrical ,,dictionary4 ,fig4 #abd4 ,,magnetization ,,curve4 ,fig4 #abe4 ,,armature3 ,,curve4 ,fig4 #abf4 ,,development ,,of ,,armature ,,curve4 ,curve of ,dynamo4 ,the characteristic curve of a dynamo4 7,see ,curve1 ,characteristic47 ,curve of ,sines4 ,an undulating curve representing wave motion4 ,it is produced by compounding a simple harmonic motion1 or a two and fro motion like that of an infinitely long pendulum with a rectilinear motion4 ,along a horizontal line points may be laid off to represent equal periods of time4 ,then on each point a perpendicular must be erected4 ,the length of each must be equal to the length of path traversed by the point up to the expiration of each one of the given intervals of time4 ,the abscissas are proportional to the times and the ordinates to the sines of angles proportional to the times4 ,thus if a circle be drawn upon the line and divided into thirty-two parts of equal angular value1 the sines of these angles may be taken as the ordinates and the absolute distance or length of arc of the angle will give the abscissas4 ,synonyms--,sine ,curve--,sinusoidal ,curve--,harmonic ,curve4 ,fig4 #abg4 ,,curve ,,of ,,sines4 #agd ,,standard ,,electrical ,,dictionary4 ,curve of ,saturation of the ,magnetic ,circuit4 ,a characteristic curve whose ordinates may represent the number of magnetic lines of force induced in a magnetic circuit1 and whose abscissas may represent the ampere turns of excitation or other representative of the inducing force4 ,curve of ,torque4 ,a characteristic curve showing the relations between torque1 q4 v41 and current in a dynamo or motor4 ,curve1 ,permeability ,temperature4 ,a characteristic curve expressing the changes in permeability of a paramagnetic substance as the temperature changes4 ,the degrees of temperature may be abscissas1 and the permeabilities corresponding thereto ordinates of the curve4 ,cut ,in4 v4 ,to connect any electric appliance1 mechanism or conductor1 into a circuit4 ,cut ,out4 v4 ,the reverse of to cut in2 to remove from a circuit any conducting device1 and sometimes so arranged as to leave the circuit completed in some other way4 ,cut ,out4 ,an appliance for removing any apparatus from an electric circuit1 so that no more current shall pass through such apparatus1 and sometimes providing means for closing the circuit so as to leave it complete after the removal of the apparatus4 #age ,,standard ,,electrical ,,dictionary4 ,cut ,out1 ,automatic4 7a7 ,a mechanism for automatically shunting an arc or other lamp when it ceases to work properly4 ,it is generally worked by an electro-magnet of high resistance placed in parallel with the arc4 ,if the arc grows too long the magnet attracts its armature1 thereby completing a shunt of approximately the resistance of the arc1 and which replaces it until the carbons approach again to within a proper distance4 ,sometimes a strip or wire of fusible metal is arranged in shunt with the arc4 ,when the arc lengthens the current through the wire increases1 melts it and a spring is released which acts to complete or close a shunt circuit of approximately arc-resistance4 7b7 ,see ,safety ,device--,safety ,fuse4 7c7 ,see below4 ,cut-out1 ,magnetic4 ,a magnetic cut-out is essentially a coil of wire with attracted core or armature4 ,when the coil is not excited the core1 by pressing down a strip of metal or by some analogous arrangement1 completes the circuit4 ,when the current exceeds a certain strength the core rises as it is attracted and the circuit is opened4 ,cut-out1 ,safety4 ,a block of porcelain or other base carrying a safety fuse1 which melts and breaks the circuit before the wire connected to it is dangerously heated4 ,synonyms--,fuse ,block--,safety ,catch--,safety ,fuse4 ,cut ,out1 ,wedge4 ,a cut out operated by a wedge4 ,the line terminals consist of a spring bearing against a plate1 the circuit being completed through their point of contact4 ,a plug or wedge composed of two metallic faces insulated from each other is adapted to wedge the contact open4 ,terminals of a loop circuit are connected to the faces of the wedge4 ,thus on sliding it into place1 the loop circuit is brought into series in the main circuit4 ,synonym--,plug ,cut ,out--,spring ,jack4 ,cutting of ,lines of ,force4 ,a field of force is pictured as made up of lines of force2 a conductor swept through the field is pictured as cutting these lines4 ,by so doing it produces potential difference or electro-motive force in itself with a current1 if the conductor is part of a closed circuit4 ,cycle of ,alternation4 ,a full period of alternation of an alternating current4 ,it begins properly at the zero line1 goes to a maximum value in one sense and returns to zero1 goes to maximum in the other sense and returns to zero4 ,cystoscopy4 ,examination of the human bladder by the introduction of a special incandescent electric lamp4 ,the method is due to ,hitze4 #agf ,,standard ,,electrical ,,dictionary4 ,damper4 7a7 ,a copper frame on which the wire in a galvanometer is sometimes coiled1 which acts to damp the oscillations of the needle4 7b7 ,a tube of brass or copper placed between the primary and secondary coils of an induction coil4 ,it cuts off induction and diminishes the current and potential of the secondary circuit4 ,on pulling it out1 the latter increases4 ,it is used on medical coils to adjust their strength of action4 ,damping4 ,preventing the indicator of an instrument from oscillating in virtue of its own inertia or elasticity4 ,in a galvanometer it is defined as resistance to quick vibrations of the needle1 in consequence of which it is rapidly brought to rest when deflected 7,ayrton74 ,in dead-beat galvanometers 7see ,galvanometer1 ,dead-,beat17 damping is desirable in order to bring the needle to rest quickly2 in ballistic galvanometers 7see ,galvanometer1 ,ballistic17 damping is avoided in order to maintain the principle of the instrument4 ,damping may be mechanical1 the frictional resistance of air to an air-vane1 or of a liquid to an immersed diaphragm or loosely fitting piston1 being employed4 ,a dash-pot1 q4 v41 is an example of the latter4 ,it may be electro-magnetic4 ,a mass of metal near a swinging magnetic needle tends by induced currents to arrest the oscillations thereof1 and is used for this purpose in dead-beat galvanometers4 ,this is termed1 sometimes1 magnetic friction4 ,the essence of damping is to develop resistance to movement in some ratio proportional to velocity1 so that no resistance is offered to the indicator slowly taking its true position4 7,see ,galvanometer1 ,dead-,beat47 ,dash-,pot4 ,a cylinder and piston1 the latter loosely fitting or perforated1 or some equivalent means being provided to permit movement4 ,the cylinder may contain a liquid such as glycerine1 or air only4 ,thus the piston is perfectly free to move1 but any oscillations are damped 7see ,damping74 ,in some arc lamps the carbon holder is connected to a dash-pot to check too sudden movements of the carbon4 ,the attachment may be either to the piston or to the cylinder4 ,in the ,brush lamp the top of the carbon holder forms a cylinder containing glycerine1 and in it a loosely fitting piston works4 ,this acts as a dash-pot4 ,dead ,beat4 adj4 ,reaching its reading quickly2 applied to instruments having a moving indicator1 which normally would oscillate back and forth a number of times before reaching its reading were it not prevented by damping4 7,see ,galvanometer1 ,aperiodic--,damping47 ,dead ,earth4 ,a fault in a telegraph line which consists in the wire being thoroughly grounded or connected to the earth4 #agg ,,standard ,,electrical ,,dictionary4 ,dead ,point of an ,alternator4 ,a two-phase alternator of the ordinary type connected as a motor to another alternator cannot start itself1 as it has dead points where the relations and polarity of field and armature are such that there is no torque or turning power4 ,dead-,turns4 ,in the winding of an armature1 a given percentage of the turns1 it may be #hj per cent41 more or less1 is assumed to be active2 the other #bj per cent4 or thereabouts1 is called dead-turns4 ,this portion represents the wire on such portions of the armature as comes virtually outside of the magnetic field4 ,they are termed dead1 as not concurring to the production of electro-motive force4 ,dead ,wire4 7a7 ,the percentage or portion of wire on a dynamo or motor armature that does not concur in the production of electromotive force4 ,the dead-turns1 q4 v41 of a drum armature or the inside wire in a ,gramme ring armature are dead wire4 7b7 ,a disused and abandoned electric conductor1 such as a telegraph wire4 7c7 ,a wire in use1 but through which1 at the time of speaking1 no current is passing4 ,death1 ,electrical4 ,death resulting from electricity discharged through the animal system4 ,the exact conditions requisite for fatal results have not been determined4 ,high electro-motive force is absolutely essential2 a changing current1 pulsatory or alternating1 is most fatal1 possibly because of the high electro-motive force of a portion of each period4 ,amperage probably has something to do with it1 although the total quantity in coulombs may be very small4 ,as applied to the execution of criminals1 the victim is seated in a chair and strapped thereto4 ,one electrode with wet padded surface is placed against his head or some adjacent part4 ,another electrode is placed against some of the lower parts1 and a current from an alternating dynamo passed for #ae seconds or more4 ,the potential difference of the electrodes is given at #a1ejj to #b1jjj volts1 but of course the maximum may be two or three times the measured amount1 owing to the character of the current4 ,decalescence4 ,the converse of recalescence1 q4 v4 ,when a mass of steel is being heated as it reaches the temperature of recalescence it suddenly absorbs a large amount of heat1 apparently growing cooler4 ,deci4 ,prefix originally used in the metric system to signify one-tenth of1 now extended to general scientific units4 ,thus decimeter means one-tenth of a meter2 decigram1 one-tenth of a gram4 ,declination1 ,angle of4 ,the angle intercepted between the true meridian and the axis of a magnetic needle at any place4 ,the angle is measured to east or west1 starting from the true meridian as zero4 #agh ,,standard ,,electrical ,,dictionary4 ,declination of the ,magnetic ,needle4 ,the deviation of the magnetic needle from the plane of the earth's meridian4 ,it is also called the variation of the compass4 7,see ,magnetic ,elements47 ,decomposition4 ,the reduction of a compound substance into its constituents1 as in chemical analysis4 ,the constituents may themselves be compounds or proximate constituents1 or may be elemental or ultimate constituents4 ,decomposition1 ,electrolytic4 ,the decomposition or separation of a compound liquid into its constituents by electrolysis4 ,the liquid must be an electrolyte1 q4 v41 and the decomposition proceeds subject to the laws of electrolysis1 q4 v4 ,see also ,electrolytic ,analysis4 ,decrement4 ,when a suspension needle which has been disturbed is oscillating the swings gradually decrease in amplitude if there is any damping1 as there always is4 ,the decrement is the ratio of the amplitude of one oscillation to the succeeding one4 ,this ratio is the same for any successive swings4 ,de-energize4 ,to cut off its supply of electric energy from an electric motor1 or any device absorbing and worked by electric energy4 ,deflagration4 ,the explosive or violent volatilizing and dissipating of a substance by heat1 violent oxidation and similar means4 ,it may be applied among other things to the destroying of a conductor by an intense current1 or the volatilization of any material by the electric arc4 ,deflecting ,field4 ,the field produced in a galvanometer by the current which is being tested1 and which field deflects the needle1 such deflection being the measure of the current strength4 ,deflection4 ,in magnetism the movement out of the plane of the magnetic meridian of a magnetic needle1 due to disturbance by or attraction towards a mass of iron or another magnet4 ,deflection ,method4 ,the method of electrical measurements in which the deflection of the index of the measuring instrument is used as the measure of the current or other element under examination4 ,it is the opposite of and is to be distinguished from the zero or null method1 q4 v4 ,in the latter conditions are established which make the index point to zero and from the conditions necessary for this the measurement is deduced4 ,the ,wheatstone ,bridge1 q4 v41 illustrates a zero method1 the sine or the tangent compass1 illustrates a deflection method4 ,the use of deflection methods involves calibration1 q4 v41 and the commercial measuring instruments1 such as ammeters and volt meters1 which are frequently calibrated galvanometers1 are also examples of deflection instruments4 #agi ,,standard ,,electrical ,,dictionary4 ,degeneration1 ,reaction of4 ,the diminished sensibility to electro-therapeutic treatment exhibited by the human system with continuance of the treatment in question4 ,the general lines of variation are stated in works on the subject4 ,deka4 ,prefix originally used in the metric system to signify multiplying by ten1 as dekameter1 ten meters1 dekagram1 ten grams2 now extended to many scientific terms4 ,de la ,rive's ,floating ,battery4 ,a small galvanic couple1 immersed in a little floating cell and connected through a coil of wire immediately above them4 ,when the exciting battery solution is placed in the cell the whole1 as it floats in a larger vessel1 turns until the coil lies at right angles to the magnetic needle4 ,sometimes the two plates are thrust through a cork and floated thus in a vessel of dilute sulphuric acid4 ,a magnet acts to attract or repel the coil in obedience to ,ampre's ,theory1 7,see ,magnetism1 ,ampere's ,theory of47 ,delaurier's ,solution4 ,a solution for batteries of the ,bunsen and ,grenet type4 ,it is of the following composition3 ,water1 #b1jjj parts2 potassium bichromate1 #ahd parts2 sulphuric acid1 #dbh parts4 ,demagnetization4 ,removal of magnetism from a paramagnetic substance4 ,it is principally used for watches which have become magnetized by exposure to the magnetic field surrounding dynamos or motors4 ,the general principles of most methods are to rotate the object1 as a watch1 in a strong field1 and while it is rotating to gradually remove it from the field1 or to gradually reduce the intensity of the field itself to zero4 ,a conical coil of wire within which the field is produced in which the watch is placed is sometimes used1 the idea being that the field within such a coil is strongest at its base4 ,such a coil supplied by an alternating current is found effectual 7,j4 ,j4 ,wright74 ,if a magnetized watch is made to turn rapidly at the end of a twisted string and is gradually brought near to and withdrawn from the poles of a powerful dynamo it may be considerably improved4 ,a hollow coil of wire connected with a pole changer and dip-battery has been used4 ,the battery creates a strong field within the coil4 ,the watch is placed there and the pole changer is worked so as to reverse the polarity of the field very frequently4 ,by the same action of the pole changer the plates of the battery are gradually withdrawn from the solution so as to gradually reduce the magnetic field to zero while constantly reversing its polarity4 7,g4 ,m4 ,hopkins47 ,steel may be demagnetized by jarring when held out of the magnetic meridian1 or by heating to redness4 #ahj ,,standard ,,electrical ,,dictionary4 ,density1 ,electric ,superficial4 ,the relative quantity of electricity residing as an electric charge upon a unit area of surface4 ,it may be positive or negative4 ,synonyms--,density of ,charge--,surface ,density4 ,dental ,mallet1 ,electric4 ,a dentist's instrument for hammering the fillings as inserted into teeth4 ,it is a little hammer held in a suitable handle1 and which is made to strike a rapid succession of blows by electro-magnetic motor mechanism4 ,depolarization4 7a7 ,the removal of permanent magnetism4 7,see ,demagnetization47 7b7 ,the prevention of the polarization of a galvanic cell4 ,it is effected in the ,grove battery by the reduction of nitric acid2 in the ,bunsen1 by the reduction of chromic acid2 in the ,smee battery1 mechanically1 by the platinum coated or rather platinized negative plate4 ,other examples will be found under the description of various cells and batteries4 ,a fluid which depolarizes is termed a depolarizer or depolarizing fluid or solution4 7,see ,electropoion ,fluid47 ,deposit1 ,electrolytic4 ,the metal or other substance precipitated by the action of a battery or other current generator4 ,derivation1 ,point of4 ,a point where a circuit branches or divides into two or more leads4 ,the separate branches then receive derived or partial currents4 ,desk ,push4 ,a press or push button1 with small flush rim1 for setting into the woodwork of a desk4 ,detector4 ,a portable galvanometer1 often of simple construction1 used for rough or approximate work4 ,detector1 ,lineman's4 ,a portable galvanometer with a high and a low resistance actuating coil1 constructed for the use of linemen and telegraph constructors when in the field1 and actually putting up1 repairing or testing lines4 ,deviation1 ,quadrantal4 ,deviation of the compass in iron or steel ships due to the magnetization of horizontal beams by the earth's induction4 ,the effect of this deviation disappears when the ship is in the plane of the electric meridian1 or at right angles thereto2 its name is taken from the fact that a swing of the ship through a quadrant brings the needle from zero deviation to a maximum and back to zero4 #aha ,,standard ,,electrical ,,dictionary4 ,deviation1 ,semicircular4 ,deviation of the compass in iron or steel ships due to vertical induction4 7,see ,induction1 ,vertical47 ,the effect of this induction disappears when the ship is in the electric meridian4 ,its name is derived from the fact that a swing of the ship through half the circle brings the needle from zero deviation to a maximum and back to zero4 ,dextrotorsal4 adj4 ,wound in the direction or sense of a right-handed screw2 the reverse of sinistrotorsal1 q4 v4 ,fig4 #abh4 ,,dextrotorsal ,,helix4 ,diacritical4 adj4 7a7 ,the number of ampere turns1 q4 v41 required to bring an iron core to one half its magnetic saturation1 q4 v41 is termed the diacritical number4 7b7 ,the diacritical point of magnetic saturation is proposed by ,sylvanus ,p4 ,thompson as a term for the coefficient of magnetic saturation which gives a magnet core one-half its maximum magnetization4 ,diagnosis1 ,electro4 ,a medical diagnosis of a patient's condition based on the action of different parts of the body under electric excitement4 ,diamagnetic4 adj4 ,possessing a negative coefficient of magnetic susceptibility2 having permeability inferior to that of air4 ,such substances placed between the poles of a magnet are repelled2 if in the form of bars1 they tend to turn so as to have their long axis at right angles to the line joining the poles4 ,the reason is that the lines of force always seek the easiest path1 and these bodies having higher reluctance than air1 impede the lines of force1 and hence are as far as possible pushed out of the way4 ,the above is the simplest explanation of a not well understood set of phenomena4 ,according to ,tyndall1 the diamagnetic force is a polar force1 the polarity of diamagnetic bodies being opposed to that of paramagnetic ones under the same conditions of excitement4 ,bismuth is the most strongly diamagnetic body known2 phosphorus1 antimony1 zinc1 and many others are diamagnetic4 7,see ,paramagnetic47 #ahb ,,standard ,,electrical ,,dictionary4 ,diagometer4 ,an apparatus for use in chemical analysis for testing the purity of substances by the time required for a charged surface to be discharged through them to earth4 ,it is the invention of ,rousseau4 ,an electrometer is charged with a dry pile4 ,one of its terminals is connected with one surface of the solution or substance to be tested1 and the other with the other surface4 ,the time of discharge gives the index of the purity of the substance4 ,diamagnetic ,polarity4 ,treating diamagnetism as due to a polar force1 the polarity of a diamagnetic body is the reverse of the polarity of iron or other paramagnetic bodies4 ,a bar-shaped diamagnetic body in a field of force tends to place itself at right angles to the lines of force4 ,diamagnetism4 7a7 ,the science or study of diamagnetic substances and phenomena4 7b7 ,the magnetic property of a diamagnetic substance4 ,diameter of ,commutation4 ,the points on the commutator of a closed circuit ring--or drum--armature1 which the brushes touch1 and whence they take the current1 mark the extremities of the diameter of commutation4 ,were it not for the lag this would be the diameter at right angles to the line connecting the centers of the opposite faces of the field4 ,it is always a little to one side of this position1 being displaced in the direction of rotation4 ,in open circuit armatures the brushes are placed on the diameter at right angles to this one1 and sometimes the term diameter of commutation is applied to it4 ,all that has been said is on the supposition that the armature divisions correspond not only in connection but in position with those of the armature coils4 ,of course1 the commutator could be twisted so as to bring the diameter of commutation into any position desired4 ,diapason1 ,electric4 ,a tuning-fork or diapason kept in vibration by electricity4 ,in general principle the ends of the fork act as armatures for an electro-magnet1 and in their motion by a mercury cup or other form of contact they make and break the circuit as they vibrate4 ,thus the magnet alternately attracts and releases the leg1 in exact harmony with its natural period of vibration4 ,diaphragm4 7a7 ,in telephones and microphones a disc of iron thrown into motion by sound waves or by electric impulses1 according to whether it acts as the diaphragm of a transmitter or receiver4 ,it is generally a plate of japanned iron such as used in making ferrotype photographs4 7,see ,telephone and ,microphone47 7b7 ,a porous diaphragm is often used in electric decomposition cells and in batteries4 ,the porous cup represents the latter use4 ,transcriber's note3 ,japanned--covered with heavy black lacquer1 like enamel paint4 #ahc ,,standard ,,electrical ,,dictionary4 ,dielectric4 ,a non-conductor2 a substance1 the different parts of which may1 after an electric disturbance1 remain1 without any process of readjustment1 and for an indefinite period of time1 at potentials differing to any extent 7,daniell74 ,there is no perfect dielectric4 ,the term dielectric is generally only used when an insulator acts to permit induction to take place through it1 like the glass of a ,leyden jar4 ,dielectric ,constant4 ,the number or coefficient expressing the relative dielectric capacity of a medium or substance4 7,see ,capacity1 ,specific ,inductive47 ,dielectric1 ,energy of4 ,in a condenser1 the conducting coatings are merely to conduct the current all over the surface they cover2 the keeping the electricities separated is the work of the dielectric1 and represents potential energy which appears in the discharge4 ,the amount of energy is proportional to the charge1 and to the potential difference4 ,as any electrified body implies an opposite electrification somewhere1 and a separating dielectric1 the existence of a condenser is always implied4 ,transcriber's note3 ,the energy stored in a capacitor 7condenser7 is 7,q99,q7_/#b;,c 7,q99,v7_/#b 7,c99,v99,v7_/#b ,the energy is proportional to the voltage ,,squared or the charge ,,squared4 ,dielectric ,polarization4 ,a term due to ,faraday4 ,it expresses what he conceived to be the condition of a dielectric when its opposite faces are oppositely electrified4 ,the molecules are supposed to be arranged by the electrification in a series of polar chains1 possibly being originally in themselves seats of opposite polarities1 or having such imparted to them by the electricities4 ,the action is analogous to that of a magnet pole on a mass of soft iron1 or on a pile of iron filings4 ,dielectric ,strain4 ,the strain a solid dielectric is subjected to1 when its opposite surfaces are electrified4 ,a ,leyden jar dilates under the strain1 and when discharged gives a dull sound4 ,the original condition is not immediately recovered4 ,jarring1 shaking1 etc41 assist the recovery from strain4 ,the cause of the strain is termed ,electric ,stress4 7,see ,stress1 ,electric47 ,this is identical with the phenomenon of residual charge4 7,see ,charge1 ,residual47 ,each loss of charge is accompanied with a proportional return of the dielectric towards its normal condition4 ,dielectric ,resistance4 ,the mechanical resistance a body offers to perforation or destruction by the electric discharge4 ,dielectric ,strength4 ,the resistance to the disruptive discharge and depending on its mechanical resistance largely or entirely4 ,it is expressible in volts per centimeter thickness4 ,dry air requires #dj1jjj volts per centimeter for a discharge4 #ahd ,,standard ,,electrical ,,dictionary4 ,differential ,winding ,working4 ,a method of working an electro-magnet intermittently1 so as to avoid sparking4 ,the magnet is wound with two coils4 ,one is connected straight into the circuit1 the other is connected in parallel therewith with a switch inserted4 ,the coils are so connected that when the switch is closed the two are in opposition1 the current going through them in opposite senses4 ,thus one overcomes the effect of the other and the magnet core shows no magnetism1 provided the two coils are of equal resistance and equal number of convolutions or turns4 ,fig4 #abi4 ,,differential ,,winding ,,working ,,of ,,electro-,,magnetic ,,apparatus4 ,diffusion4 ,a term properly applied to the varying current density found in conductors of unequal cross sectional area4 ,in electro-therapeutics it is applied to the distribution of current as it passes through the human body4 ,its density per cross-sectional area varies with the area and with the other factors4 ,diffusion ,creep4 ,when electrodes of an active circuit are immersed in a solution of an electrolyte1 a current passes electrolytically if there is a sufficient potential difference4 ,the current passes through all parts of the solution1 spreading out of the direct prism connecting or defined by the electrodes4 ,to this portion of the current the above term is applied4 ,if the electrodes are small enough in proportion to the distance between them the current transmission or creep outside of the line becomes the principal conveyor of the current so that the resistance remains the same for all distances4 ,dimensions and ,theory of ,dimensions4 ,the expression of the unitary value of a physical quantity in one or more of the units of length 7,l71 time 7,t7 and mass 7,m7 is termed the dimensions of such quantity4 ,thus the dimension or dimensions of a distance is simply ,l2 of an angle1 expressible by dividing the arc by the radius is ,l_/,l2 of a velocity1 expressible by distance divided by time--,l_/,t2 of acceleration1 which is velocity acquired in a unit of time1 and is therefore expressible by velocity divided by time--,l_/,t_/,t or ,l_/,t#b2 of momentum1 which is the product of mass into velocity--,m99,l_/,t2 of kinetic energy taken as the product of mass into the square of velocity--,m997,l#b_/,t#b72 of potential energy taken as the product of mass into acceleration into space-,m997,l_/,t#b799,l reducing to ,m997,l#b_/,t#b74 ,the theory is based on three fundamental units and embraces all electric quantities4 ,the simple units generally taken are the gram1 centimeter and second and the dimensions of the fundamental compound units are expressed in terms of these three1 forming the centimeter-gram-second or ,c4 ,g4 ,s4 system of units4 ,unless otherwise expressed or implied the letters ,l1 ,m and ,t1 may be taken to indicate centimeter1 gram and second respectively4 ,it is obvious that very complicated expressions of dimensions may be built up1 and that a mathematical expression of unnamed quantities may be arrived at4 ,dimensions in their application by these symbols are subject to the laws of algebra4 ,they were invented by ,fourier and were brought into prominence by ,j4 ,clerk ,maxwell4 ,another excellent definition reads as follows3 ,by the dimensions of a physical quantity we mean the quantities and powers of quantities1 involved in the measurement of it4 7,w4 ,t4 ,a4 ,emtage47 #ahe ,,standard ,,electrical ,,dictionary4 ,dimmer4 ,an adjustable choking coil used for regulating the intensity of electric incandescent lights4 ,some operate by the introduction and withdrawal of an iron core as described for the choking coil 7see ,coil1 ,choking71 others by a damper of copper1 often a copper ring surrounding the coil and which by moving on or off the coil changes the potential of the secondary circuit4 ,dip of ,magnetic ,needle4 ,the inclination of the magnetic needle4 7,see ,elements1 ,magnetic47 ,dipping4 7a7 ,acid or other cleaning processes applied by dipping metals in cleaning or pickling solutions before plating in the electroplater's bath4 7b7 ,plating by dipping applies to electroplating without a battery by simple immersion4 ,copper is deposited on iron from a solution of copper sulphate in this way4 ,synonym--,simple ,immersion4 ,dipping ,needle4 ,a magnet mounted in horizontal bearings at its centre of gravity4 ,placed in the magnetic meridian it takes the direction of the magnetic lines of force of the earth at that point4 ,it is acted on by the vertical component of the earth's magnetism1 as it has no freedom of horizontal movement4 7,see ,magnetic ,elements1 and ,compass1 ,inclination47 ,directing ,magnet4 ,in a reflecting galvanometer the magnet used for controlling the magnetic needle by establishing a field4 ,it is mounted on the spindle of the instrument above the coil and needle4 ,synonym--,controlling ,magnet4 #ahf ,,standard ,,electrical ,,dictionary4 ,direction4 7a7 ,the direction of an electric current is assumed to be from a positively charged electrode or terminal to a negatively charged one in the outer circuit4 7,see ,current47 7b7 ,the direction of magnetic and electro-magnetic lines of force is assumed to be from north to south pole of a magnet in the outer circuit4 ,it is sometimes called the positive direction4 ,their general course is shown in the cuts diagrammatically4 ,the circles indicate a compass used in tracing their course4 ,the magnetic needle tends to place itself in the direction of or tangential to the lines of force passing nearest it4 7c7 ,the direction of electrostatic lines of force is assumed to be out of a positively charged and to a negatively charged surface4 ,fig4 #acj4 ,,direction ,,of ,,lines ,,of ,,force ,,of ,a ,,permanent ,,magnet4 ,fig4 #aca1 ,,direction ,,of ,,lines ,,of ,,force ,,of ,,an ,,electro-,,magnet4 #ahg ,,standard ,,electrical ,,dictionary4 ,directive ,power4 ,in magnetism the power of maintaining itself in the plane of the magnetic meridian1 possessed by the magnetic needle4 ,discharge1 ,brush4 ,the static discharge of electricity into or through the air may be of the brush or spark form4 ,the brush indicates the escape of electricity in continuous flow2 the spark indicates discontinuity4 ,the conditions necessary to the production of one or the other refer to the nature of the conductor1 and of other conductors in its vicinity and to the electro-motive force or potential difference2 small alterations may transform one into the other4 ,the brush resembles a luminous core whose apex touches the conductor4 ,it is accompanied by a slight hissing noise4 ,its luminosity is very feeble4 ,the negative conductor gives a smaller brush than that of the positive conductor and discharges it more readily4 ,when electricity issues from a conductor1 remote from an oppositely excited one1 it gives an absolutely silent discharge1 showing at the point of escape a pale blue luminosity called electric glow1 or if it escapes from points it shows a star-like centre of light4 ,it can be seen in the dark by placing a point on the excited conductor of a static-electric machine4 ,synonyms--,silent ,discharge--,glow ,discharge4 ,discharge1 ,conductive4 ,a discharge of a static charge by conduction through a conductor4 ,discharge1 ,convective4 ,the discharge of static electricity from an excited conductor through air or rarefied gas2 it is also called the quiet or silent discharge4 ,the luminous effect in air or gas at atmospheric pressures takes the form of a little brush from a small positive electrode2 the negative shows a star4 ,the phenomena of ,gassiot's cascade1 the philosopher's egg and ,geissler tubes1 all of which may be referred to1 are instances of convective discharge4 ,discharge1 ,dead ,beat4 ,a discharge that is not oscillatory in character4 ,discharge1 ,disruptive4 ,a discharge of a static charge through a dielectric4 ,it involves mechanical perforation of the dielectric1 and hence the mere mechanical strength of the latter has much to do with preventing it4 ,a disruptive discharge is often oscillatory in character2 this is always the case with the discharge of a ,leyden jar4 #ahh ,,standard ,,electrical ,,dictionary4 ,discharge1 ,duration of4 ,the problem of determining this factor has been attacked by various observers4 ,wheatstone with his revolving mirror found it to be #a_/bdjjj second4 ,fedderson1 by interposing resistance1 prolonged it to #ad_/ajjjj and again to #ach_/ajjjj second4 ,lucas ,cazin made it from #bf to #dg millionths of a second4 ,all these experiments were performed with ,leyden jars4 ,discharge1 ,impulsive4 ,a disruptive discharge produced between conductors by suddenly produced potential differences4 ,the self-induction of the conductor plays an especially important part in discharges thus produced4 ,discharge1 ,lateral4 7a7 ,a lightning discharge1 which sometimes takes place between a lightning rod and the building on which it is4 7b7 ,in the discharge of a ,leyden jar or condenser the discharge which takes the alternative path1 q4 v4 ,discharge1 ,oscillatory4 ,the sudden or disruptive discharge of a static condenser1 such as a ,leyden jar1 or of many other charged conductors1 is oscillatory in character4 ,the direction of the currents rapidly changes1 so that the discharge is really an alternating current of excessively short total duration4 ,the discharge sends electro-magnetic waves through the ether1 which are exactly analogous to those of light but of too long period to affect the eye4 ,synonym--,surging ,discharge4 ,transcriber's note3 ,marconi's transmission across the ,english channel occurs in #ahig1 five years after the publication of this book4 ,fig4 #acb4 ,,discharger4 ,discharger4 ,an apparatus for discharging ,leyden jars4 ,it consists of a conductor terminating in balls1 and either jointed like a tongs or bent with a spring-action1 so that the balls can be set at distances adapted to different sized jars4 ,it has an insulating handle or a pair of such4 ,in use one ball is brought near to the coating and the other to the spindle ball of the jar4 ,when nearly or quite in contact the jar discharges4 ,synonyms--,discharging ,rod--,discharging ,tongs4 #ahi ,,standard ,,electrical ,,dictionary4 ,discharger1 ,universal4 ,an apparatus for exposing substances to the static discharge spark4 ,it consists of a base with three insulating posts4 ,the central post carries an ivory table to support the object4 ,the two side posts carry conducting rods1 terminating in metal balls1 and mounted with universal joints4 ,a violent shock can be given to any object placed on the table4 ,synonym--,henley's ,universal ,discharger4 ,discharge1 ,silent4 ,this term is sometimes applied to the glow or brush discharge and sometimes to the condition of electric effluvium4 7,see ,discharge1 ,brush--,effluvium1 ,electric47 ,discharge1 ,spark4 ,the discontinuous discharge of high tension electricity through a dielectric or into the air produces electric sparks4 ,these are quite strongly luminous1 of branching sinuous shape1 and in long sparks the luminosity varies in different parts of the same spark4 ,a sharp noise accompanies each spark4 ,high density of charge is requisite for the formation of long sparks4 ,disconnection4 ,the separation of two parts of1 or opening a circuit1 as by turning a switch1 unscrewing a binding screw1 or the like4 ,the term is sometimes used to indicate a class of faults in telegraph circuits4 ,disconnections may be total1 partial or intermittent1 and due to many causes1 such as open or partially replaced switches1 oxidized or dirty contact points1 or loose joints4 ,displacement1 ,electric4 ,a conception of the action of charging a dielectric4 ,the charge is all on the surface4 ,this fact being granted1 the theory of displacement holds that charging a body is the displacing of electricity1 forcing it from the interior on to the surface1 or vice versa1 producing a positive or negative charge by displacement of electricity4 ,while displacement is taking place in a dielectric there is assumed to be a movement or current of electricity called a displacement current4 ,disruptive ,tension4 ,when the surface of a body is electrified1 it tends to expand1 all portions of the surface repelling each other4 ,the film of air surrounding such a body is electrified too1 and is subjected to a disruptive tension1 varying in intensity with the square of the density4 ,dissimulated ,electricity4 ,the electricity of a bound charge4 7,see ,charge1 ,bound47 ,dissociation4 ,the separation of a chemical compound into its elements by a sufficiently high degree of heat4 ,all compounds are susceptible of dissociation1 so that it follows that combustion is impossible at high temperatures4 #aij ,,standard ,,electrical ,,dictionary4 ,distance1 ,critical1 of ,alternative ,path4 ,the length of air gap in an alternative path whose resistance joined to the impedance of the rest of the conductors of the path just balances the impedance of the other path4 ,distance1 ,sparking4 ,the distance between electrodes1 which a spark from a given ,leyden jar or other source will pass across4 ,synonym--,explosive ,distance4 ,distillation4 ,the evaporation of a liquid by heat1 and sometimes in a vacuum1 followed by condensation of the vapors1 which distil or drop from the end of the condenser4 ,it is claimed that the process is accelerated by the liquid being electrified4 ,distributing ,box4 ,in an electric conduit system1 a small iron box provided for giving access to the cable for the purpose of making house and minor connections4 ,synonym--,hand ,hole4 ,distributing ,switches4 ,switch systems for enabling different dynamos to supply different lines of a system as required4 ,spring jacks1 q4 v41 are used for the lines1 and plug switches for the dynamo leads4 ,thus1 dynamos can be thrown in or out as desired1 without putting out the lights4 ,distribution of ,electric ,energy1 ,systems of4 ,the systems of electric current distribution from central stations or from private generating plants1 mechanical or battery1 the latter primary or secondary4 ,they include in general the alternating current system and direct current systems4 ,again1 these may be subdivided into series and multiple arc1 multiple-series and series-multiple distribution1 and the three1 four1 or five wire system may be applied to multiple arc or multiple series systems4 7,see ,alternating ,current--,current ,system--,multiple ,arc--,multiple ,series--,series ,multiple--,three ,wire ,system47 ,door ,opener1 ,electric4 ,an apparatus for opening a door by pushing back the latch4 ,a spring then draws the door open1 and it is closed against the force of the spring by the person entering4 ,electro-magnetic mechanism actuates the latch1 and is operated by a switch or press-button4 ,thus a person on the upper floor can open the hall door without descending4 ,dosage1 ,galvanic4 ,in electro-therapeutics the amount of electric current or discharge1 and duration of treatment given to patients4 ,double ,carbon ,arc ,lamp4 ,an arc lamp designed to burn all night1 usually constructed with two parallel sets of carbons1 one set replacing the other automatically1 the current being switched from the burnt out pair to the other by the action of the mechanism of the lamp4 #aia ,,standard ,,electrical ,,dictionary4 ,double ,fluid ,theory4 ,a theory of electricity4 ,electricity is conveniently treated as a fluid or fluids4 ,according to the double fluid hypothesis negative electricity is due to a preponderance of negative fluid and vice versa4 ,like fluid repels like1 and unlike attracts unlike2 either fluid is attracted by matter2 the presence in a body of one or the other induces electrification2 united in equal proportions they neutralize each other1 and friction1 chemical decomposition and other causes effect their separation4 ,the hypothesis1 while convenient1 is overshadowed by the certainty that electricity is not really a fluid at all4 7,see ,single ,fluid ,theory--,fluid1 ,electric47 ,synonym--,symmer's ,theory4 ,transcriber's note3 ,current is the motion of negative electrons in a conductor or plasma4 ,unequal distribution of electrons is static electricity4 ,the relatively immobile nuclei of atoms are positive when one or more of its electrons is absent and accounts for part of the current in electrolysis and plasmas4 ,double ,fluid ,voltaic ,cell4 ,a cell in which two fluids are used1 one generally as depolarizer surrounding the negative plate1 the other as excitant surrounding the positive plate4 ,a porous diaphragm or difference in specific gravities is used to keep the solutions separate and yet permit the essential electrolytic diffusion4 ,grove's ,cell1 ,bunsen's ,cell1 and ,daniell's ,cell1 all of which may be referred to1 are of this type1 as are many others4 ,double ,wedge4 ,a plug for use with a spring-jack4 ,it has connection strips at its end and another pair a little distance back therefrom1 so that it can make two loop connections at once4 ,synonym--,double ,plug4 ,doubler4 ,a continuously acting electrophorous1 q4v42 an early predecessor of the modern electric machines4 ,it is now no longer used4 ,d4 ,p4 ,abbreviation for ,potential ,difference4 ,drag4 ,the pull exercised by a magnetic field upon a conductor moving through it or upon the motion of an armature in it4 ,dreh-strom4 7,german7 ,rotatory currents2 a system of currents alternating in periodic succession of phases and producing a rotatory field4 7,see ,field1 ,rotatory--,multiphase ,currents47 ,drill ,electric4 ,a drill for metals or rock worked by an electro-magnetic motor4 ,for metals a rotary motion1 for rocks a reciprocating or percussion action is imparted4 ,it is used by shipbuilders for drilling holes in plates which are in place in ships1 as its flexible conductors enable it to be placed anywhere4 ,for rock-drilling a solenoid type of construction is adopted1 producing rapid percussion4 #aib ,,standard ,,electrical ,,dictionary4 ,drip ,loop4 ,a looping downward of wires entering a building1 so that rain water1 as it runs along the wire1 will drip from the lowest part of the loop instead of following the wire into or against the side of the building4 ,driving ,horns4 ,projections on the periphery of an armature of a dynamo for holding the winding in place and preventing its displacement4 ,various arrangements have been adopted4 ,they are sometimes wedges or pins and are sometimes driven into spaces left in the drum core4 ,the toothed disc armature cores make up an armature in which the ridges formed by the teeth form practically driving horns4 ,dronier's ,salt4 ,a substance for solution for use in bichromate batteries4 ,it is a mixture of one-third potassium bichromate and two-thirds potassium bisulphate4 ,it is dissolved in water to make the exciting fluid4 ,drop1 ,automatic4 ,a switch or circuit breaker1 operating to close a circuit by dropping under the influence of gravity4 ,it is held up by a latch1 the circuit remaining open1 until the latch is released by a current passing through an electro-magnet4 ,this attracting an armature lets the drop fall4 ,as it falls it closes a local or second circuit1 and thus may keep a bell ringing until it is replaced by hand4 ,it is used in burglar alarms1 its function being to keep a bell ringing even though the windows or door by which entrance was made is reclosed4 #aic ,,standard ,,electrical ,,dictionary4 ,fig4 #acc4 ,,the ,,magic ,,drum4 ,drum1 ,electric4 ,a drum with a mechanism within for striking the head with a hammer or some equivalent method so as to be used as a piece of magical apparatus4 ,in the one shown in the cut a sort of telephone action is used to produce the sound1 the electro-magnet ,d and armature being quite screened from observation through the hole4 7,see ,fig4 #acc7 ,a ring1 ,c1 shown in ,fig4 #acc1 with two terminals1 the latter shown by the unshaded portions a a1 and a suspending hook ,e1 also with two terminals1 and two suspending conductors ,a1 ,b1 carry the current to the magnet4 ,a sudden opening or closing of the circuit produces a sound4 ,dub's ,laws4 #a4 ,the magnetism excited at any transverse section of a magnet is proportional to the square root of the distance between the given section and the end4 #b4 ,the free magnetism at any given transverse section of a magnet is proportional to the difference between the square root of half the length of the magnet and the square root of the distance between the given section and the nearest end4 ,duct4 ,the tube or compartment in an electric subway for the reception of a cable4 7,see ,conduit1 ,electric ,subway47 ,dyad4 ,a chemical term2 an element which in combination replaces two monovalent elements2 one which has two bonds or is bivalent4 ,dyeing1 ,electric4 ,the producing mordanting or other dyeing effects on goods in dyeing by the passage of an electric current4 ,dynamic ,electricity4 ,electricity of relatively low potential and large quantity2 current electricity as distinguished from static electricity2 electricity in motion4 #aid ,,standard ,,electrical ,,dictionary4 ,dynamo1 ,alternating ,current4 ,a dynamo-electric machine for producing an alternating current2 an alternator4 ,they are classified by ,s4 ,p4 ,thompson into three classes--,i4 ,those with stationary field-magnet and rotating armature4 ,,ii4 ,those with rotating field magnet and stationary armature4 ,,iii4 ,those with both field magnet part and armature part stationary1 the amount of magnetic induction from the latter through the former being caused to vary or alternate in direction by the revolution of appropriate pieces of iron1 called inductors4 ,another division rests on whether they give one simple alternating current1 a two phase current1 or whether they give multi phase currents4 7,see ,current1 ,alternating--,currents1 ,multiphase47 ,a great many kinds of alternators have been constructed4 ,only an outline of the general theory can be given here4 ,they are generally multipolar1 with north and south poles alternating around the field4 ,the armature coils1 equal in number in simple current machines1 to the poles1 are wound in opposite senses1 so that the current shall be in one direction1 though in opposite senses1 in all of them at anyone time4 ,as the armature rotates the coils are all approaching their poles at one time and a current in one sense is induced in every second coil1 and one in the other sense in the other coils4 ,they are all in continuous circuit with two open terminals1 each connected to its own insulated connecting ring on the shaft4 ,as the coils pass the poles and begin to recede from them the direction changes1 and the current goes in the other direction until the next poles are reached and passed4 ,thus there are as many changes of direction of current per rotation as there are coils in the armature or poles in the field4 ,fig4 #acd4 ,,alternating ,,current ,,dynamo ,,with ,,separate ,,exciter ,,mounted ,,on ,,main ,,shaft4 #aie ,,standard ,,electrical ,,dictionary4 ,the field-magnets whose windings may be in series are often excited by a separate direct current generation4 ,some are self-exciting1 one or more of the armature coils being separated from the rest1 and connected to a special commutator1 which rectifies its current4 ,by properly spacing the coils with respect to the poles of the field1 and connecting each set of coils by itself to separate connecting rings1 several currents can be taken from the same machine1 which currents shall have a constant difference in phase4 ,it would seem at first sight that the same result could be attained by using as many separate alternators as there were currents to be produced4 ,but it would be almost impossible to preserve the exact relation of currents and current phase where each was produced by its own machine4 ,the currents would overrun each other or would lag behind4 ,in a single machine with separate sets of coils the relation is fixed and invariable4 ,fig4 ,i#ce4 ,,diagram ,,of ,,arrangement ,,of ,,armature ,,coils ,,and ,,collecting ,,rings ,,in ,,an ,,alternating ,,current ,,dynamo4 ,dynamo1 ,alternating ,current1 ,regulation of4 ,transformers1 converters1 or induction coils are used to regulate alternating current dynamos1 somewhat as compound winding is applied in the case of direct-current dynamos4 ,the arrangement consists in connecting the primary of an induction coil or transformer into the external circuit with its secondary connected to the field circuit4 ,thus the transformer conveys current to the field picked up from the main circuit1 and represents to some extent the shunt of a direct-current machine4 ,dynamo1 ,commercial ,efficiency of4 ,the coefficient1 q4 v41 obtained by dividing the mechanically useful or available work of a dynamo by the mechanical energy absorbed by it4 ,this only includes the energy available in the outer circuit1 for doing useful work4 #aif ,,standard ,,electrical ,,dictionary4 ,fig4 #acf4 ,,compound ,,wound ,,dynamo4 ,dynamo4 ,compound4 ,a compound wound dynamo2 one which has two coils on its field magnet2 one winding is in series with the external circuit and armature2 the other winding is in parallel with the armature winding1 or else with the armature winding and field winding1 both in series4 7,see ,winding1 ,long ,shunt--,winding1 ,short ,shunt47 ,such a dynamo is1 to a certain extent1 self-regulating1 the two coils counteracting each other1 and bringing about a more regular action for varying currents than that of the ordinary shunt or series dynamo4 ,the extent of the regulation of such a machine depends on the proportions given its different parts4 ,however good the self-regulating may be in a compound wound machine1 it can only be perfect at one particular speed4 ,to illustrate the principle on which the approximate regulation is obtained the characteristic curve diagram may be consulted4 ,fig4 #acg4 ,,curves ,,of ,,series ,,and ,,shunt ,,windings ,,superimposed4 ,one curve is the curve of a series winding1 the other that of a shunt winding1 and shows the variation of voltage in each with resistance in the external or working circuit4 ,the variation is opposite in each case4 ,it is evident that the two windings could be so proportioned on a compound machine that the resultant of the two curves would be a straight line4 ,this regulation would then be perfect and automatic1 but only for the one speed4 #aig ,,standard ,,electrical ,,dictionary4 ,dynamo1 ,direct ,current4 ,a dynamo giving a current of unvarying direction1 as distinguished from an alternator or alternating current dynamo4 ,dynamo1 ,disc4 ,a dynamo with a disc armature1 such as ,pacinotti's disc1 q4 v4 7,see also ,disc1 ,armature47 ,the field magnets are disposed so that the disc rotates close to their poles1 and the poles face or are opposite to the side or sides of the disc4 ,the active leads of wire are those situated on the face or faces of the disc4 ,fig4 #ach4 ,,polechko',s ,,disc ,,dynamo4 ,dynamo-electric ,machine4 ,a machine driven by power1 generally steam power1 and converting the mechanical energy expended on driving it into electrical energy of the current form4 ,the parts of the ordinary dynamo may be summarized as follows3 ,first1 ,a circuit as complete as possible of iron4 ,such circuit is composed partly of the cores of an electro-magnet or of several electro-magnets1 and partly of the cylindrical or ring-shaped core of an armature which fits as closely as practicable between the magnet ends or poles which are shaped so as to partly embrace it4 ,second1 of coils of insulated wire wound upon the field-magnet cores4 ,when these coils are excited the field-magnets develop polarity and the circuit just spoken of becomes a magnetic circuit1 interrupted only by the air gaps between the poles and armatures4 ,thirdly1 of coils of insulated wire upon the armature core4 ,these coils when rotated in the magnetic field cut magnetic lines of force and develop electro-motive force4 #aih ,,standard ,,electrical ,,dictionary4 ,fourthly1 of collecting mechanism1 the commutator in direct current dynamos1 attached to the armature shaft and rotating with it4 ,this consists of insulated rings1 or segments of rings to which the wire coils of the armature are connected1 and on which two springs of copper or plates of carbon or some other conductor presses4 ,the electro-motive force developed by the cutting of lines of force1 by the wires of the armature1 shows itself as potential difference between the two springs4 ,if the ends of a conductor are attached1 one to each of these brushes1 the potential difference will establish a current through the wire4 ,by using properly divided and connected segments on the commutator the potential difference and consequent direction of the current may be kept always in the same sense or direction4 ,it is now clear that the external wire may be connected with the windings of the field-magnet4 ,in such case the excitement of the field-magnets is derived from the armature and the machine is self-excited and entirely self-contained4 ,the above is a general description of a dynamo4 ,sometimes the coils of the field-magnets are not connected with the armature1 but derive their current from an outside source4 ,such are termed separately excited dynamos4 ,some general features of dynamo generators may be seen in the definitions under this head and elsewhere4 ,the general conception is to cut lines of force with a conductor and thus generate electromotive force1 or in some way to change the number of lines of force within a loop or circuit with the same effect4 ,dynamo1 ,electroplating4 ,a dynamo designed for low potential and high current intensity4 ,they are wound for low resistance1 frequently several wires being used in parallel1 or ribbon1 bar or rectangular conductors being employed4 ,they are of the direct current type4 ,they should be shunt wound or they are liable to reverse4 ,they are sometimes provided with resistance in the shunt1 which is changed as desired to alter the electro-motive force4 ,dynamo1 ,equalizing4 ,a combination for three and five-wire systems4 ,a number of armatures or of windings on the same shaft are connected across the leads4 ,if the potential drops at any pair of mains1 the armature will begin to be driven by the other mains1 acting to an extent as an element of a motor1 and will raise the potential in the first pair4 ,dynamo1 ,far ,leading4 ,a motor dynamo1 used to compensate the drop of potential in long mains4 ,into the mains at a distant point a series motor is connected1 driving a dynamo placed in shunt across the mains4 ,the dynamo thus driven raises the potential difference between the two mains4 #aii ,,standard ,,electrical ,,dictionary4 ,dynamograph4 ,a printing telegraph in which the message is printed at both transmitting and receiving ends4 ,dynamo1 ,inductor4 ,a generator in which the armature or current-generating windings are all comprised upon the poles of the field magnets4 ,masses of iron1 which should be laminated and are the inductors1 are carried past the field magnet poles concentrating in their passage the lines of force1 thus inducing currents in the coils4 ,in one construction shown in the cut the field magnets a1 a 44 are ,u shaped and are arranged in a circle1 their poles pointing inwards4 ,a single exciting coil c1 c 444 is wound around the circle in the bend of the ,v-shaped segments4 ,the poles carry the armature coils e1 e 444 ,the laminated inductors i1 i 444 are mounted on a shaft ,s1 by spiders h1 to be rotated inside the circle of magnets1 thus generating an alternating current4 ,synonym--,inductor ,generator4 ,fig4 #aci4 ,,inductor ,,dynamo4 ,dynamo1 ,interior ,pole4 ,a dynamo with a ring armature1 with field magnet pole pieces which extend within the ring4 #bjj ,,standard ,,electrical ,,dictionary4 ,dynamo1 ,iron ,clad4 ,a dynamo in which the iron of the field magnet is of such shape as to enclose the field magnet coils as well as the armature4 ,dynamometer4 ,a device or apparatus for measuring force applied1 or rate of expenditure of energy by1 or work done in a given time by a machine4 ,a common spring balance can be used as a force dynamometer1 viz3 to determine how hard a man is pulling and the like4 ,the steam engine indicator represents an energy-dynamometer of the graphic type1 the instrument marking an area whence1 with the aid of the fixed factors of the engine1 the work done may be determined4 ,prony's ,brake1 q4 v41 is a type of the friction dynamometer1 also of the energy type4 ,in the latter type during the experiment the whole power must be turned on or be expended on the dynamometer4 ,dynamo1 ,motor4 ,a motor dynamo is a machine for 7a7 converting a continuous current at any voltage to a continuous current of different strength at a different voltage or for 7b7 transforming a continuous current into an alternating one1 and vice versa4 ,for the first type see ,transformer1 ,continuous ,current2 for the second type see ,transformer1 ,alternating ,current4 ,dynamo1 ,multipolar4 ,a dynamo having a number of field magnet poles1 not merely a single north and a single south pole4 ,the field magnet is sometimes of a generally circular shape with the poles arranged radially within it1 the armature revolving between the ends4 ,dynamo1 ,non-polar4 ,a name given by ,prof4 ,george ,forbes to a dynamo invented by him4 ,in it a cylinder of iron rotates within a perfectly self-contained iron-clad field magnet4 ,the current is taken off by brushes bearing near the periphery1 at two extremities of a diameter4 ,a machine with a disc #ah inches in diameter was said to give #c1aag amperes1 with #e4h volts ,e4 ,m4 ,f4 running at #a1ejj revolutions per second4 ,the ,e4 ,m4 ,f4 of such machines varies with the square of the diameter of the disc or cylinder4 ,dynamo1 ,open ,coil4 ,a dynamo the windings of whose armatures may be grouped in coils1 which are not connected in series1 but which have independent terminals4 ,these terminals are separate divisions of the commutator and so spaced that the collecting brushes touch each pair belonging to the same coil simultaneously4 ,as the brushes come in contact with the sections forming the terminals they take current from the coil in question4 ,this coil is next succeeded by another one1 and so on according to the number of coils employed4 ,dynamo1 ,ring4 ,a dynamo the base of whose field magnets is a ring in general shape1 or perhaps an octagon1 and with poles projecting inwardly therefrom4 #bja ,,standard ,,electrical ,,dictionary4 ,dynamo1 ,coupling of4 ,dynamos can be coupled exactly like batteries and with about the same general results4 ,an instance of series coupling would be given by the dynamos in the three wire system when no current is passing through the neutral wire1 and when the lamps on each side of it are lighted in equal number4 ,dynamo1 ,self-exciting4 ,a dynamo which excites its own field4 ,the majority of dynamos are of this construction4 ,others1 especially alternating current machines1 are separately excited1 the field magnets being supplied with current from a separate dynamo or current generator4 ,dynamo1 ,separate ,circuit4 ,a dynamo in which the field magnet coils are entirely disconnected from the main circuit1 and in which current for the field is supplied by special coils carried for the purpose by the same armature1 or by a special one1 in either case a special commutator being provided to collect the current4 ,dynamo1 ,separately ,excited4 ,a dynamo whose field magnets are excited by a separate current generator1 such as a dynamo or even a battery4 ,alternating current dynamos are often of this construction4 ,direct current dynamos are not generally so4 ,the term is the opposite of self-exciting4 ,fig4 #adj4 ,,series ,,dynamo4 ,dynamo1 ,series4 ,a dynamo whose armature1 field winding1 and external circuit are all in series4 ,in such a dynamo short circuiting or lowering the resistance of the external circuit strengthens the field1 increases the electro-motive force and current strength and may injure the winding by heating the wire1 and melting the insulation4 #bjb ,,standard ,,electrical ,,dictionary4 ,dynamo1 ,shunt4 ,a dynamo whose field is wound in shunt with the external circuit4 ,two leads are taken from the brushes2 one goes around the field magnets to excite them2 the other is the external circuit4 ,in such a dynamo the lowering of resistance on the outer circuit takes current from the field and lowers the electro-motive force of the machine4 ,short circuiting has no heating effect4 ,fig4 #ada4 ,,shunt ,,dynamo4 ,dynamo1 ,single ,coil4 ,a dynamo whose field magnet is excited by a single coil4 ,several such have been constructed1 with different shapes of field magnet cores1 in order to obtain a proper distribution of poles4 ,dynamo1 ,tuning ,fork4 ,a dynamo in which the inductive or armature coils were carried at the ends of the prongs of a gigantic tuning fork1 and were there maintained in vibration opposite the field magnets4 ,it was invented by ,t4 ,a4 ,edison1 but never was used4 ,dynamo1 ,uni-polar4 ,a dynamo in which the rotation of a conductor effects a continuous increase in the number of lines cut1 by the device of arranging one part of the conductor to slide on or around the magnet4 7,s4 ,p4 ,thomson47 ,faraday's disc is the earliest machine of this type4 #bjc ,,standard ,,electrical ,,dictionary4 ,dyne4 ,the ,c4 ,g4 ,s4 or fundamental unit of force4 ,it is the force which can impart an acceleration of one centimeter per second to a mass of one gram in one second4 ,it is equal to about #a_/iha the weight of a gram1 this weight varying with the latitude4 ,earth4 7a7 ,the earth is arbitrarily taken as of zero electrostatic potential4 ,surfaces in such condition that their potential is unchanged when connected to the earth are said to be of zero potential4 ,all other surfaces are discharged when connected to the earth1 whose potential1 for the purposes of man at least1 never changes4 7b7 ,as a magnetic field of force the intensity of the earth's field is about one-half a line of force per square centimeter4 7c7 ,the accidental grounding of a telegraph line is termed an earth1 as a dead1 total1 partial1 or intermittent earth1 describing the extent and character of the trouble4 ,transcriber's note3 ,fallen power lines can produce voltage gradients on the earth's surface that make walking in the area dangerous1 as in hundreds of volts per foot4 ,lightning may be associated with substantial changes in the static ground potential4 ,earth1 ,dead4 ,a fault1 when a telegraph or other conductor is fully connected to earth or grounded at some intermediate point4 ,synonyms--,solid ,earth--,total ,earth4 ,earth1 ,partial4 ,a fault1 when a telegraph or other conductor is imperfectly connected to earth or grounded at some intermediate point4 ,earth ,plate4 ,a plate buried in the earth to receive the ends of telegraph lines or other circuits to give a ground1 q4 v4 ,a copper plate is often used4 ,a connection to a water or gas main gives an excellent ground1 far better than any plate4 ,when the plate oxidizes it is apt to introduce resistance4 ,earth ,return4 ,the grounding of a wire of a circuit at both ends gives the circuit an earth return4 ,earth1 ,swinging4 ,a fault1 when a telegraph or other conductor makes intermittent connection with the earth4 ,it is generally attributable to wind action swinging the wire1 whence the name4 ,ebonite4 ,hard vulcanized ,india rubber1 black in color4 ,specific resistance in ohms per cubic centimeter at #df ,c4 7#aae ,f473 #cd;,e#ae 7,ayrton72 specific inductive capacity1 7air #a73 #b4ef 7,wllner72 #b4gf 7,schiller72 #c4ae 7,boltzmann74 ,it is used in electrical apparatus for supporting members such as pillars1 and is an excellent material for frictional generation of potential4 ,its black color gives it its name1 and is sometimes made a point of distinction from ,vulcanite1 q4 v4 #bjd ,,standard ,,electrical ,,dictionary4 ,economic ,coefficient4 ,the coefficient of electric efficiency4 7,see ,efficiency1 ,electric47 ,edison ,effect4 ,a continuous discharge resulting in a true current which takes place between a terminal of an incandescent lamp filament and a plate placed near it4 ,the lamp must be run at a definitely high voltage to obtain it4 ,ediswan4 ,an abbreviation for ,edison-,swan2 the trade name of the incandescent lamp used in ,great ,britain1 and of other incandescent system apparatus4 ,fig4 #adb4 ,,gymnotus ,,electricus4 ,eel1 ,electric 7,gymnotus ,electricus74 ,an eel capable of effecting the discharge of very high potential electricity1 giving painful or dangerous shocks4 ,its habitat is the fresh water1 in ,south ,america4 ,faraday investigated it and estimated its shock as equal to that from fifteen ,leyden jars1 each of #a4ff square feet of coating4 7,see ,animal ,electricity and ,ray1 ,electric47 ,effect1 ,counter-inductive4 ,a counter-electro-motive force due to induction1 and opposing a current4 ,efficiency4 ,the relation of work done to energy absorbed4 ,a theoretically perfect machine would have the maximum efficiency in which the two qualities named would be equal to each other4 ,expressed by a coefficient1 q4 v41 the efficiency in such case would be equal to #a4 ,if a machine produced but half the work represented by the energy it absorbed1 the rest disappearing in wasteful expenditure1 in heating the bearings1 in overcoming the resistance of the air and in other ways1 its efficiency would be expressed by the coefficient #a_/b or 4#e1 or if one hundred was the basis1 by fifty per centum4 ,there are a number of kinds of efficiencies of an electric generator which are given below4 ,efficiency1 ,commercial4 ,practical efficiency of a machine1 obtained by dividing the available output of work or energy of a machine by the energy absorbed by the same machine4 ,thus in a dynamo part of the energy is usefully expended in exciting the field magnet1 but this energy is not available for use in the outer circuit1 is not a part of the output1 and is not part of the dividend4 ,if ,m represents the energy absorbed1 and ,w the useful or available energy1 the coefficient of commercial efficiency is equal to ,w_/,m4 ,m is made up of available1 unavailable and wasted 7by ,foucault currents1 etc417 energy4 ,calling available energy ,w1 unavailable but utilized energy w1 and wasted energy m1 the expression for the coefficient of commercial efficiency becomes ,w _/ 7 ,w w m 7 when ,m ,w w m ,synonym--,net efficiency4 #bje ,,standard ,,electrical ,,dictionary4 ,efficiency1 ,electrical4 ,in a dynamo or generator the relation of total electric energy produced1 both wasted and useful or available to the useful or available electrical energy4 ,if we call ,w the useful electric and w the wasted electric energy1 the coefficient of electrical efficiency is equal to ,w _/ 7 ,w w 7 ,synonyms--,intrinsic ,efficiency--,economic ,coefficient--,coefficient of ,electrical ,efficiency4 ,efficiency of ,conversion4 ,in a dynamo or generator the relation of energy absorbed to total electric energy produced4 ,part of the electric energy is expended in producing the field and in other ways4 ,thus a generator with high efficiency of conversion may be a very poor one1 owing to the unavailable electric energy which it produces4 ,the coefficient of ,efficiency of ,conversion is obtained by dividing the total electric energy produced by the energy absorbed in working the dynamo4 ,if ,m represents the energy absorbed1 or work done in driving the dynamo or generator1 ,w the useful electric1 and w the wasted electrical energy1 then the coefficient of efficiency of conversion is equal to 7,w w 7 _/ ,m ,in the quantity ,m are included besides available 7,w7 and unavailable 7w7 electric energy1 the totally wasted energy due to ,foucault currents1 etc41 calling the latter m1 the above formula may be given 7 ,w w 7 _/ 7,w w m 7 ,this coefficient may refer to the action of a converter1 q4 v41 in the alternating system4 ,synonym--,gross ,efficiency4 ,efficiency of ,secondary ,battery1 ,quantity4 ,the coefficient obtained by dividing the ampere-hours obtainable from a secondary battery by the ampere hours required to charge it4 ,efficiency of ,secondary ,battery1 ,real4 ,the coefficient obtained by dividing the energy obtainable from a secondary battery by the energy absorbed in charging it4 ,the energy is conveniently taken in watt-hours and includes the consideration of the spurious voltage4 7,see ,battery1 ,secondary47 #bjf ,,standard ,,electrical ,,dictionary4 ,efflorescence4 ,the appearance of a dry salt upon the walls of a vessel containing a solution above the normal water-line from evaporation of a liquid4 ,it appears in battery jars and in battery carbons1 in the latter interfering with the electrical connections1 and oxidizing or rusting them4 7,see ,creeping47 ,effluvium1 ,electric4 ,when a gas is made to occupy the position of dielectric between two oppositely electrified surfaces a peculiar strain or condition of the dielectric is produced1 which promotes chemical change4 ,the condition is termed electrical effluvium or the silent discharge4 ,by an apparatus specially constructed to utilize the condition large amounts of ozone are produced4 ,synonym--,silent ,discharge4 ,elastic ,curve4 ,a crude expression for a curve without projections or sudden sinuosities2 such a curve as can be obtained by bending an elastic strip of wood4 ,electrepeter4 ,an obsolete name for a key1 switch or pole changer of any kind4 ,elasticity1 ,electric4 ,the phenomenon of the dielectric is described under this term4 ,when a potential difference is established between two parts of the dielectric1 a flow of electricity displacement current starts through the dielectric1 which current is due to the electric stress1 but is instantly arrested by what has been termed the electric elasticity of the dielectric4 ,this is expressed by 7 electric stress 7 _/ 7 electric strain 7 and in any substance is inversely proportional to the specific inductive capacity4 ,electricity4 ,it is impossible in the existing state of human knowledge to give a satisfactory definition of electricity4 ,the views of various authorities are given here to afford a basis for arriving at the general consensus of electricians4 ,we have as yet no conception of electricity apart from the electrified body2 we have no experience of its independent existence4 7,j4 ,e4 ,h4 ,gordon47 ,what is ,electricity8 ,we do not know1 and for practical purposes it is not necessary that we should know4 7,sydney ,f4 ,walker47 ,electricity ''' is one of those hidden and mysterious powers of nature which has thus become known to us through the medium of effects4 7,weale's ,dictionary of ,terms47 ,this word ,electricity is used to express more particularly the cause1 which even today remains unknown1 of the phenomena that we are about to explain4 7,amde ,guillemin47 #bjg ,,standard ,,electrical ,,dictionary4 ,electricity is a powerful physical agent which manifests itself mainly by attractions and repulsions1 but also by luminous and heating effects1 by violent commotions1 by chemical decompositions1 and many other phenomena4 ,unlike gravity1 it is not inherent in bodies1 but it is evoked in them by a variety of causes ''' 7,ganot's ,physics47 ,electricity and magnetism are not forms of energy2 neither are they forms of matter4 ,they may1 perhaps1 be provisionally defined as properties or conditions of matter2 but whether this matter be the ordinary matter1 or whether it be1 on the other hand1 that all-pervading ether by which ordinary matter is surrounded1 is a question which has been under discussion1 and which now may be fairly held to be settled in favor of the latter view4 7,daniell's ,physics47 ,the name used in connection with an extensive and important class of phenomena1 and usually denoting the unknown cause of the phenomena or the science that treats of them4 7,imperial ,dictionary47 ,electricity4 4 4 is the imponderable physical agent1 cause1 force or the molecular movement1 by which1 under certain conditions1 certain phenomena1 chiefly those of attraction and repulsion1 4 4 4 are produced4 7,john ,angell47 ,it has been suggested that if anything can rightly be called electricity1 this must be the ether itself2 and that all electrical and magnetic phenomena are simply due to changes1 strains and motions in the ether4 ,perhaps negative electrification4 4 4means an excess of ether1 and positive electrification a defect of ether1 as compared with the normal density4 7,w4 ,larden47 ,electricity is the name given to the supposed agent producing the described condition 7i4 e4 electrification7 of bodies4 7,fleeming ,jenkin47 ,there are certain bodies which1 when warm and dry1 acquire by friction1 the property of attracting feathers1 filaments of silk or indeed any light body towards them4 ,this property is called ,electricity1 and bodies which possess it are said to be electrified4 7,linnaeus ,cumming47 ,what electricity is it is impossible to say1 but for the present it is convenient to look upon it as a kind of invisible something which pervades all bodies4 7,w4 ,perren ,maycock47 ,what is electricity8 ,no one knows4 ,it seems to be one manifestation of the energy which fills the universe and which appears in a variety of other forms1 such as heat1 light1 magnetism1 chemical affinity1 mechanical motion1 etc4 7,park ,benjamin47 #bjh ,,standard ,,electrical ,,dictionary4 ,the theory of electricity adopted throughout these lessons is1 that electricity1 whatever its true nature1 is one1 not two2 that this ,electricity1 whatever it may prove to be1 is not matter1 and is not energy2 that it resembles both matter and energy in one respect1 however1 in that it can neither be created nor destroyed4 7,sylvanus ,p4 ,thomson47 ,in ,physics a name denoting the cause of an important class of phenomena of attraction and repulsion1 chemical decomposition1 etc41 or1 collectively1 these phenomena themselves4 7,century ,dictionary47 ,a power in nature1 often styled the electric fluid1 exhibiting itself1 when in disturbed equilibrium or in activity1 by a circuit movement1 the fact of direction in which involves polarity1 or opposition of properties in opposite directions2 also1 by attraction for many substances1 by a law involving attraction between substances of unlike polarity1 and repulsion between those of like2 by exhibiting accumulated polar tension when the circuit is broken2 and by producing heat1 light1 concussion1 and often chemical changes when the circuit passes between the poles1 or through any imperfectly conducting substance or space4 ,it is evolved in any disturbance of molecular equilibrium1 whether from a chemical1 physical1 or mechanical cause4 7,webster's ,dictionary47 ,in point of fact electricity is not a fluid at all1 and only in a few of its attributes is it at all comparable to a fluid4 ,let us rather consider electricity to be a condition into which material substances are thrown4 4 47,slingo ,brooker47 ,transcriber's note3 #bjjh ,dictionary3 ,phenomena arising from the behavior of electrons and protons caused by the attraction of particles with opposite charges and the repulsion of particles with the same charge4 ,electricity1 ,cal4 ,the electricity produced in the secondary of a transformer by changes of temperature in the core4 ,this is in addition to the regularly induced current4 ,synonym--,acheson ,effect4 ,electrics4 ,substances developing electrification by rubbing or friction2 as ,gilbert1 the originator of the term1 applied it1 it would indicate dielectrics4 ,he did not know that1 if insulated1 any substance was one of his electrics4 ,a piece of copper held by a glass handle becomes electrified by friction4 ,electrification4 ,the receiving or imparting an electric charge to a surface2 a term usually applied to electrostatic phenomena4 ,electrization4 ,a term in electro-therapeutics2 the subjection of the human system to electric treatment for curative1 tonic or diagnostic purposes4 ,electro-biology4 ,the science of electricity in its relation to the living organism1 whether as electricity is developed by the organism1 or as it affects the same when applied from an external source4 #bji ,,standard ,,electrical ,,dictionary4 ,electro-capillarity4 ,the relations between surface tension1 the potential difference and the electrostatic capacity of fluids in contact4 ,although nominally in contact such surfaces are separated by about one-twenty-millionth of a centimeter 7#a_/ejjjjjjj inch7 2 thus a globule of mercury and water in which it is immersed constitute an electrostatic accumulator of definite electrostatic capacity4 ,again the mercury and water being in electric connection differ in potential by contact 7see ,contact ,theory74 ,a definite surface tension is also established4 ,any change in one of these factors changes the other also4 ,a current passed through the contact surfaces will change the surface tension and hence the shape of the mercury globule4 ,shaking the globule will change its shape and capacity and produce a current4 ,heating will do the same4 7,see ,electrometer1 ,capillary2 and ,telephone1 ,capillary47 ,mercury and water are named as liquids in which the phenomena are most conveniently observed4 ,they are observable in other parallel cases4 ,electro-chemical ,equivalent4 ,the quantity of an element or compound liberated from or brought into combination1 electrolytically1 by one coulomb of electricity4 ,the electro-chemical equivalent of hydrogen is found by experiment to be 4#jjjjaje gram4 ,that of any other substance is found by multiplying this weight by its chemical equivalent referred to hydrogen1 which is its atomic or molecular weight divided by its valency4 ,thus the atomic weight of oxygen is #af1 its valency is #b1 its equivalent is #af_/b #h2 its electro-chemical equivalent is equal to 4#jjjjaje ,x #h 4#jjjhdj gram4 ,electro-chemical ,series4 ,an arrangement of the elements in the order of their relative electrical affinities so that each element is electro-negative to all the elements following it1 and electro-positive to the elements preceding it4 ,the usual series begins with oxygen as the most electro-negative and ends with potassium as the most electro-positive element4 ,there is1 of course1 no reason why other series of compound radicals1 such as sulphion 7,,so#d71 etc41 should not also be constructed4 ,for each liquid acting on substances a separate series of the substances acted on may be constructed4 ,thus for dilute sulphuric acid the series beginning with the negatively charged or most attacked one is zinc1 amalgamated or pure1 cadmium1 iron1 tin1 lead1 aluminum1 nickel1 antimony1 bismuth1 copper1 silver1 platinum4 ,in other liquids the series is altogether different4 ,electro--chemistry4 ,the branch of electricity or of chemistry treating of the relations between electric and chemical force in different compounds and reactions4 7,see ,electrolysis--,electrochemical series--,electro-chemical ,equivalent 47 #baj ,,standard ,,electrical ,,dictionary4 ,electro-culture4 ,the application of electricity to the cultivation of plants4 ,in one system wires are stretched or carried across the bed under the surface1 and some are connected to one pole and others to the other pole of a galvanic battery of two or more elements4 ,in some experiments improved results have thus been obtained4 ,another branch refers to the action of the electric arc light on vegetation4 ,this has an effect on vegetation varying in results4 ,electrode4 7a7 ,the terminal of an open electric circuit4 7b7 ,the terminals of the metallic or solid conductors of an electric circuit1 immersed in an electrolytic solution4 7c7 ,the terminals between which a voltaic arc is formed1 always in practice made of carbon1 are termed electrodes4 7d7 ,in electro-therapeutics many different electrodes are used whose names are generally descriptive of their shape1 character1 or uses to which they are to be applied4 ,such are aural electrodes for the ears1 and many others4 7e7 ,the plates of a voltaic battery4 ,electrode1 ,indifferent4 ,a term in electro-therapeutics4 ,an electrode to which no therapeutic action is attributed but which merely provides a second contact with the body to complete the circuit through the same4 ,the other electrode is termed the therapeutic electrode4 ,electrodes1 ,erb's ,standards of4 ,proposed standard sizes for medical electrodes as follows3 ,name4 ,diameter4 ,fine ,electrode1 #a_/b centimeter 4#b inch ,small #b 4#h ,medium #g4e #c4j ,large #f,x#b #b4d ,x 4#h ,very large #afx#h #f4d x #c4b ,electrodes1 ,non-polarizable4 ,in electro-therapeutics electrodes whose contact surface is virtually porous clay saturated with zinc chloride solution4 ,the series terminate in amalgamated zinc ends1 enclosed each in a glass tube1 and closed with clay4 ,contact of metal with the tissues is thus avoided4 ,electrode1 ,therapeutic4 ,a term in electro-therapeutics4 ,an electrode applied to the body for the purpose of inducing therapeutic action1 or for giving the basis for an electric diagnosis of the case4 ,the other electrode is applied to complete the circuit only2 it is termed the indifferent electrode4 ,electro-diagnosis4 ,the study of the condition of a patient by the reactions which occur at the terminals or kathode and anode of an electric circuit applied to the person4 ,the reactions are divided into kathodic and anodic reactions4 #baa ,,standard ,,electrical ,,dictionary4 ,electro-dynamic4 adj4 ,the opposite of electrostatic2 a qualification of phenomena due to current electricity4 ,synonym--,electro-kinetic4 ,electro-dynamic ,attraction and ,repulsion4 ,the mutual attraction and repulsion exercised by currents of electricity upon each other4 ,the theory of the cause is based upon stress of the luminiferous ether and upon the reaction of lines of force upon each other4 ,for a resum of the theory see ,induction1 ,electro-magnetic4 ,electro-dynamics4 ,the laws of electricity in a state of motion2 the inter-reaction of electric currents4 ,it is distinguished from electro-magnetic induction as the latter refers to the production of currents by induction4 ,the general laws of electro-dynamics are stated under ,induction1 ,electro-magnetic1 q4 v4 ,synonym--,electro-kinetics4 ,fig4 #adc4 ,,diagram ,,of ,,connections ,,of ,,siemens' ,,electro-,,dynamometer4 #bab ,,standard ,,electrical ,,dictionary4 ,electro-dynamometer1 ,siemens'4 ,an apparatus for measuring currents by the reaction between two coils1 one fixed and one movable1 through which the current to be measured passes4 ,it is one of the oldest commercial ammeters or current measurers4 ,it comprises a fixed coil of a number of convolutions and a movable coil often of only one convolution surrounding the other4 ,the movable coil is suspended by a filament or thread from a spiral spring4 ,the spring is the controlling factor4 ,connection is established through mercury cups so as to bring the two coils in series4 ,in use the spring and filament are adjusted by turning a milled head to which they are connected until the coils are at right angles4 ,then the current is turned on and deflects the movable coil4 ,the milled head is turned until the deflection is overcome4 ,the angle through which the head is turned is proportional to the square of the current4 ,the movable coil must in its position at right angles to the fixed one lie at right angles to the magnetic meridian4 ,thus in the diagram1 ,fig4 #adc ,a ,b ,c ,d is the fixed coil2 ,e ,f ,g ,h is the movable coil2 ,s is the spiral spring attached at ,k to the movable coil4 ,the arrows show the course of the current as it goes through the coils4 ,electrolier4 ,a fixture for supporting electric lamps2 the analogue in electric lighting of the gasolier or gas chandelier4 ,often both are combined1 the same fixture being piped and carrying gas burners1 as well as being wired and carrying electric lamps4 ,electrolysis4 ,the separation of a chemical compound into its constituent parts or elements by the action of the electric current4 ,the compound may be decomposed into its elements1 as water into hydrogen and oxygen1 or into constituent radicals1 as sodium sulphate into sodium and sulphion1 which by secondary reactions at once give sodium hydrate and sulphuric acid4 ,the decomposition proceeds subject to the laws of electrolysis4 7,see ,electrolysis1 ,laws of47 ,for decomposition to be produced there is for each compound a minimum electro-motive force or potential difference required4 ,the current passes through the electrolyte or substance undergoing decomposition entirely by ,electrolytic ,conduction1 q4 v4 in accordance with ,grothss' ,hypothesis1 q4 v4 ,the electrolyte therefore must be susceptible of diffusion and must be a fluid4 ,the general theory holds that under the influence of a potential difference between electrodes immersed in an electrolyte1 the molecules touching the electrodes are polarized1 in the opposite sense for each electrode4 ,if the potential difference is sufficient the molecules will give up one of their binary constituents to the electrode1 and the other constituent will decompose the adjoining molecule1 and that one being separated into the same two constituents will decompose its neighbor1 and so on through the mass until the other electrode is reached4 ,this one separates definitely the second binary constituent from the molecules touching it4 #bac ,,standard ,,electrical ,,dictionary4 ,thus there is an exact balance preserved4 ,just as many molecules are decomposed at one electrode as at the other1 and the exact chain of decomposition runs through the mass4 ,each compound electrolyzed develops a binary or two-fold composition1 and gives up one constituent to one electrode and the other to the other4 ,fig4 #add4 ,,action ,,of ,,molecules ,,in ,a ,,solution ,,before ,,and ,,during ,,electrolysis4 ,the cut shows the assumed polarization of an electrolyte4 ,the upper row shows the molecules in irregular order before any potential difference has been produced1 in other words1 before the circuit is closed4 ,the next row shows the first effects of closing the circuit1 and also indicates the polarization of the mass1 when the potential difference is insufficient for decomposition4 ,the third row indicates the decomposition of a chain of molecules1 one constituent separating at each pole4 #bad ,,standard ,,electrical ,,dictionary4 ,electrolysis1 ,laws of4 ,the following are the principal laws1 originally discovered by ,faraday1 and sometimes called ,faraday's ,laws of ,electrolysis3 #a4 ,electrolysis cannot take place unless the electrolyte is a conductor4 ,conductor here means an electrolytic conductor1 one that conducts by its own molecules traveling1 and being decomposed4 7,see ,grothss' ,hypothesis47 ,,ii4 ,the energy of the electrolytic action of the current is the same wherever exercised in different parts of the circuit4 ,,iii4 ,the same quantity of electricity--that is the same current for the same period----- decomposes chemically equivalent quantities of the bodies it decomposes1 or the weights of elements separated in electrolytes by the same quantity of electricity 7in coulombs or some equivalent unit7 are to each other as their chemical equivalent4 ,,iv4 ,the quantity of a body decomposed in a given time is proportional to the strength of the current4 ,to these may be added the following3 ,v4 ,a definite and fixed electro-motive force is required for the decomposition of each compound1 greater for some and less for others4 ,without sufficient electro-motive force expended on the molecule no decomposition will take place4 7,see ,current1 ,convective47 ,electrolyte4 ,a body susceptible of decomposition by the electric current1 and capable of electrolytic conduction4 ,it must be a fluid body and therefore capable of diffusion1 and composite in composition4 ,an elemental body cannot be an electrolyte4 ,electrolytic ,analysis4 ,chemical analysis by electrolysis4 ,the quantitative separation of a number of metals can be very effectively executed4 ,thus1 suppose that a solution of copper sulphate was to be analyzed4 ,a measured portion of the solution would be introduced into a weighed platinum vessel4 ,the vessel would be connected to the zinc plate terminal of a battery4 ,from the other terminal of the battery a wire would be brought and would terminate in a plate of platinum4 ,this would be immersed in the solution in the vessel4 ,as the current would pass the copper sulphate would be decomposed and eventually all the copper would be deposited in a firm coating on the platinum4 ,the next operations would be to wash the metal with distilled water1 and eventually with alcohol1 to dry and to weigh the dish with the adherent copper4 ,on subtracting the weight of the dish alone from the weight of the dish and copper1 the weight of the metallic copper in the solution would be obtained4 ,in similar ways many other determinations are effected4 ,the processes of analysis include solution of the ores or other substances to be analyzed and their conversion into proper form for electrolysis4 ,copper as just described can be precipitated from the solution of its sulphate4 ,for iron and many other metals solutions of their double alkaline oxalates are especially available forms for analysis4 ,the entire subject has been worked out in considerable detail by ,classen1 to whose works reference should be made for details of processes4 ,electrolytic ,convection4 ,it is sometimes observed that a single cell of ,daniell battery1 for instance1 or other source of electric current establishing too low a potential difference for the decomposition of water seems to produce a feeble but continuous decomposition4 ,this is very unsatisfactorily accounted for by the hydrogen as liberated combining with dissolved oxygen4 7,ganot47 ,the whole matter is obscure4 7,see ,current1 ,convection47 #bae ,,standard ,,electrical ,,dictionary4 ,electrolytic ,conduction4 ,conduction by the travel of atoms or radicals from molecule to molecule of a substance with eventual setting free at the electrodes of the atoms or radicals as elementary molecules or constituent radicals4 ,a substance to be capable of acting as an electrolytic conductor must be capable of diffusion1 and must also have electrolytic conductivity4 ,such a body is called an electrolyte4 7,see ,grothss' ,hypothesis--,electrolysis-- ,electrolysis1 ,laws of--,electro-chemical ,equivalent47 ,electro-magnet4 ,a mass1 in practice always of iron1 around which an electric circuit is carried1 insulated from the iron4 ,when a current is passed through the circuit the iron presents the characteristics of a magnet4 7,see ,magnetism1 ,ampre's ,theory of--,solenoid--,lines of ,force47 ,in general terms the action of a circular current is to establish lines of force that run through the axis of the circuit approximately parallel thereto1 and curving out of and over the circuit1 return into themselves outside of the circuit4 ,if a mass of iron is inserted in the axis or elsewhere near such current1 it multiplies within itself the lines of force1 q4 v4 7,see also ,magnetic ,permeability--,permeance--,magnetic ,induction1 ,coefficient of ,magnetic ,susceptibility--,magnetization1 ,coefficient of ,induced47 ,these lines of force make it a magnet4 ,on their direction1 which again depends on the direction of the magnetizing current1 depends the polarity of the iron4 ,the strength of an electro-magnet1 below saturation of the core 7see ,magnetic ,saturation71 is proportional nearly to the ampere-turns1 q4 v4 ,more turns for the same current or more current for the same turns increase its strength4 ,in the cut is shown the general relation of current1 coils1 core and line of force4 ,assume that the magnet is looked at endwise1 the observer facing one of the poles2 then if the current goes around the core in the direction opposite to that of the hands of a clock1 such pole will be the north pole4 ,if the current is in the direction of the hands of a clock the pole facing the observer will be the south pole4 ,the whole relation is exactly that of the theoretical ,amprian currents1 already explained4 ,the direction and course of the lines of force created are shown in the cut4 ,the shapes of electro-magnets vary greatly4 ,the cuts show several forms of electro-magnets4 ,a more usual form is the horseshoe or double limb magnet1 consisting generally of two straight cores1 wound with wire and connected and held parallel to each other by a bar across one end1 which bar is called the yoke4 ,in winding such a magnet the wire coils must conform1 as regards direction of the current in them to the rule for polarity already cited4 ,if both poles are north or both are south poles1 then the magnet cannot be termed a horseshoe magnet1 but is merely an anomalous magnet4 ,in the field magnets of dynamos the most varied types of electro-magnets have been used4 ,consequent poles are often produced in them by the direction of the windings and connections4 ,to obtain the most powerful magnet the iron core should be as short and thick as possible in order to diminish the reluctance of the magnetic circuit4 ,to obtain a greater range of action a long thin shape is better1 although it involves waste of energy in its excitation4 #baf ,,standard ,,electrical ,,dictionary4 ,fig4 #ade ,,diagram ,,of ,,an ,,electro-,,magnet ,,showing ,,relation ,,of ,,current ,,and ,,winding ,,to ,,its ,,polarity ,,and ,,lines ,,of ,,force4 ,fig4 #adf4 ,,annular ,,electro-,,magnet ,electro-magnet1 ,annular4 ,an electro-magnet consisting of a cylinder with a circular groove cut in its face1 in which groove a coil of insulated wire is placed4 ,on the passage of a current the iron becomes polarized and attracts an armature towards or against its grooved face4 ,the cut shows the construction of an experimental one4 ,it is in practice applied to brakes and clutches4 ,in the cut of the electro-magnetic brake 7see ,brake1 ,electro-magnetic71 ,c is the annular magnet receiving its current through the brushes1 and pressed when braking action is required against the face of the moving wheel4 ,the same arrangement1 it can be seen1 may apply to a clutch4 #bag ,,standard ,,electrical ,,dictionary4 ,fig4 #adg4 ,,bar ,,electro-,,magnet4 ,electro-magnet1 ,bar4 ,a straight bar of iron surrounded with a magnetizing coil of wire4 ,bar electromagnets are not much used1 the horseshoe type being by far the more usual4 ,electro-magnet1 ,club-foot4 ,an electro-magnet1 one of whose legs only is wound with wire1 the other being bare4 ,fig4 #adh4 ,,club-,,foot ,,electro-,,magnets ,,with ,,hinged ,,armatures4 ,electro-magnet1 ,hinged4 ,an electro-magnet whose limbs are hinged at the yoke4 ,on excitation by a current the poles tend to approach each other4 ,fig4 #adi4 ,,electro-,,magnet1 ,,hinged ,electro-magnetic ,attraction and ,repulsion4 ,the attraction and repulsion due to electromagnetic lines of force1 which lines always tend to take as short a course as possible and also seek the medium of the highest permeance4 ,this causes them to concentrate in iron and steel or other paramagnetic substance and to draw them towards a magnet by shortening the lines of force connecting the two4 ,it is exactly the same attraction as that of the permanent magnet for its armature1 ,ampre's theory bringing the latter under the same title4 ,in the case of two magnets like poles repel and unlike attract4 ,in the case of simple currents1 those in the same direction attract and those in opposite directions repel each other4 ,this refers to constant current reactions4 ,thus the attraction of unlike poles of two magnets is1 by the ,amprian theory1 the attraction of two sets of currents of similar direction1 as is evident from the diagram4 ,the repulsion of like poles is the repulsion of unlike currents and the same applies to solenoids1 q4 v4 7,see ,magnetism and do4 ,ampre's ,theory of--,induction1 ,electro-dynamic--,electro-magnetic ,induction47 #bah ,,standard ,,electrical ,,dictionary4 ,electro-magnetic ,control4 ,control of a magnet1 iron armature1 or magnetic needle in a galvanometer1 ammeter1 voltmeter or similar instrument by an electro-magnetic field1 the restitutive force being derived from an electro-magnet4 ,the restitutive force is the force tending to bring the index to zero4 ,electro-magnetic ,field of ,force4 ,a field of electro-magnetic lines of force1 q4 v41 established through the agency of an electric current4 ,a wire carrying a current is surrounded by circular concentric lines of force which have the axis of the wire as the locus of their centres4 ,electro-magnets produce lines of force identical with those produced by permanent magnets4 7,see ,field of ,force--,magnetic ,field of ,force--,controlling ,field--,deflecting ,field47 ,electro-magnetic ,induction4 ,when two currents of unlike direction are brought towards each other1 against their natural repulsive tendency work is done1 and the consequent energy takes the form of a temporary increase in both currents4 ,when withdrawn1 in compliance with the natural tendency of repulsion1 the currents are diminished in intensity1 because energy is not expended on the withdrawal1 but the withdrawal is at the expense of the energy of the system4 ,the variations thus temporarily produced in the currents are examples of electro-magnetic induction4 ,the currents have only the duration in each case of the motion of the circuits4 ,one circuit is considered as carrying the inducer current and is termed the primary circuit and its current the primary current1 the others are termed the secondary circuit and current respectively4 ,we may assume a secondary circuit in which there is no current4 ,it is probable that there is always an infinitely small current at least1 in every closed circuit4 ,then an approach of the circuits will induce in the secondary an instantaneous current in the reverse direction4 ,on separating the two circuits a temporary current in the same direction is produced in the secondary4 #bai ,,standard ,,electrical ,,dictionary4 ,a current is surrounded by lines of force4 ,the approach of two circuits1 one active1 involves a change in the lines of force about the secondary circuit4 ,lines of force and current are so intimately connected that a change in one compels a change in the other4 ,therefore the induced current in the secondary may be attributed to the change in the field of force in which it lies1 a field maintained by the primary circuit and current4 ,any change in a field of force induces a current or change of current in any closed circuit in such field1 lasting as long as the change is taking place4 ,the new current will be of such direction as to oppose the change4 7,see ,lenz's ,law47 ,the action as referred to lines of force may be figured as the cutting of such lines by the secondary circuit1 and such cutting may be brought about by moving the secondary in the field4 7,see ,lines of ,force--,field of ,force47 ,the cutting of #a;,e#h lines of force per second by a closed circuit induces an electro-motive force of one volt4 7,see ,induction1 ,mutual1 ,coefficient of47 ,electro-magnet1 ,iron ,clad4 ,a magnet whose coil and core are encased in a iron jacket1 generally connected to one end of the core4 ,this gives at one end two poles1 one tubular1 the other solid1 and concentric with each other4 ,it is sometimes called a tubular magnet4 ,electro-magnet1 ,one ,coil4 ,an electro-magnet excited by one coil4 ,in some dynamos the field magnets are of this construction1 a single coil1 situated about midway between the poles1 producing the excitation4 ,electro-magnetic ,leakage4 ,the leakage of lines of force in an electro-magnet2 the same as magnetic leakage4 7,see ,magnetic ,leakage47 ,electro-magnetic ,lines of ,force4 ,the lines of force produced in an electro-magnetic field4 ,they are identical with ,magnetic ,lines of ,force1 q4 v4 7,see also ,field of ,force-,line of ,force47 ,electro-magnetic ,stress4 ,the stress in an electro-magnetic field of force1 showing itself in the polarization of light passing through a transparent medium in such a field4 7,see ,magnetic ,rotary ,polarization47 ,electro-magnetic ,theory of ,light4 ,this theory is due to ,j4 ,clark ,maxwell1 and the recent ,hertz experiments have gone far to prove it4 ,it holds that the phenomena of light are due to ether waves1 identical in general factors with those produced by electro-magnetic induction of alternating currents acting on the ether4 ,in a non-conductor any disturbance sets an ether wave in motion owing to its restitutive force2 electricity does not travel through such a medium1 but can create ether waves in it4 ,therefore a non-conductor of electricity is permeable to waves of ether or should transmit light1 or should be transparent4 ,a conductor on the other hand transmits electrical disturbances because it has no restitutive force and cannot support an ether wave4 ,hence a conductor should not transmit light1 or should be opaque4 ,with few exceptions dielectrics or non-conductors are transparent1 and conductors are opaque4 #bbj ,,standard ,,electrical ,,dictionary4 ,again1 the relation between the electrostatic and electro-magnet units of quantity is expressed by #a 3 #cj1jjj1jjj1jjj2 the latter figure in centimeters gives approximately the velocity of light4 ,the electro-magnetic unit depending on electricity in motion should have this precise relation if an electro-magnetic disturbance was propagated with the velocity of light4 ,if an electrically charged body were whirled around a magnetic needle with the velocity of light1 it should act in the same way as a current circulating around it4 ,this effect to some extent has been shown experimentally by ,rowland4 ,a consequence of these conclusions is 7,maxwell7 that the specific inductive capacity of a non-conductor or dielectric should be equal to the square of its index of refraction for waves of infinite length4 ,this is true for some substances--sulphur1 turpentine1 petroleum and benzole4 ,in others the specific inductive capacity is too high1 e4 g41 vegetable and animal oils1 glass1 ,iceland spar1 fluor spar1 and quartz4 ,electro-magnetic ,unit of ,energy4 ,a rate of transference of energy equal to ten meg-ergs per second4 ,electro-magnetism4 ,the branch of electrical science treating of the magnetic relations of a field of force produced by a current1 of the reactions of electro-magnetic lines of force1 of the electromagnetic field of force1 of the susceptibility1 permeability1 and reluctance of diamagnetic and paramagnetic substances1 and of electro-magnets in general4 ,electro-magnet1 ,long ,range4 ,an electro-magnet so constructed with extended pole pieces or otherwise1 as to attract its armature with reasonably constant force over a considerable distance4 ,the coil and plunger1 q4 v41 mechanisms illustrate one method of getting an extended range of action4 ,when a true electro-magnet is used1 one with an iron core1 only a very limited range is attainable at the best4 7,see ,electro-magnet1 ,stopped ,coil--do4 ,plunger47 ,electro-magnet1 ,plunger4 ,an electro-magnet with hollow coils1 into which the armature enters as a plunger4 ,to make it a true electro-magnet it must have either a yoke1 incomplete core1 or some polarized mass of iron4 ,electro-magnet1 ,polarized4 ,an electro-magnet consisting of a polarized or permanently magnetized core wound with magnetizing coils1 or with such coils on soft iron cores mounted on its ends4 ,the coils may be wound and connected so as to cooperate with or work against the permanent magnet on which it is mounted4 ,in ,hughes' magnet shown in the cut it is mounted in opposition1 so that an exceedingly feeble current will act to displace the armature1 a1 which is pulled away from the magnet by a spring1 s4 #bba ,,standard ,,electrical ,,dictionary4 ,fig4 #aej ,,hughes' ,,polarized ,,electro-,,magnet ,electro-magnets1 ,interlocking4 ,electro-magnets so arranged that their armatures interlock4 ,thus two magnets1 ,a ,a and ,b ,b1 may be placed with their armatures1 ,m and ,n1 at right angles and both normally pulled away from the poles4 ,when the armature ,m is attracted a catch on its end is retained by a hole in the end of the other armature ,n1 and when the latter armature ,n is attracted by its magnet the armature ,m is released4 ,in the mechanism shown in the cut the movements of the wheel ,r are controlled4 ,normally it is held motionless by the catch upon the bottom of the armature ,m1 coming against the tooth projecting from its periphery4 ,a momentary current through the coils of the magnet ,a ,a releases it1 by attracting ,m1 which is caught and retained by ,n1 and leaves it free to rotate4 ,a momentary current through the coils of the magnet ,b ,b again releases ,m1 which drops down and engages the tooth upon ,r and arrests its motion4 ,fig4 #aea4 ,,interlocking ,,electro-,,magnets4 #bbb ,,standard ,,electrical ,,dictionary4 ,electro-magnet1 ,stopped ,coil4 ,an electro-magnet consisting of a tubular coil1 in which a short fixed core is contained1 stopping up the aperture to a certain distance1 while the armature is a plunger entering the aperture4 ,this gives a longer range of action than usual4 ,electro-magnet1 ,surgical4 ,an electro-magnet1 generally of straight or bar form1 fitted with different shaped pole pieces1 used for the extraction of fragments of iron or steel from the eyes4 ,some very curious cases of successful operations on the eyes of workmen1 into whose eyes fragments of steel or iron had penetrated1 are on record4 ,electro-medical ,baths4 ,a bath for the person provided with connections and electrodes for causing a current of electricity of any desired type to pass through the body of the bather4 ,like all electro-therapeutical treatment1 it should be administered under the direction of a physician only4 ,electro-metallurgy4 7a7 ,in the reduction of ores the electric current has been proposed but never extensively used1 except in the reduction of aluminum and its alloys4 7,see ,reduction of ,ores1 ,electric47 7b7 ,electro-plating and deposition of metal from solutions is another branch4 7,see ,electroplating and ,electrotyping47 7c7 ,the concentration of iron ores by magnetic attraction may come under this head4 7,see ,magnetic ,concentration of ,ores47 ,electrometer4 ,an instrument for use in the measurement of potential difference1 by the attraction or repulsion of statically charged bodies4 ,they are distinguished from galvanometers as the latter are really current measurers1 even if wound for use as voltmeters1 depending for their action upon the action of the current circulating in their coils4 ,electrometer1 ,absolute4 ,an electrometer designed to give directly the value of a charge in absolute units4 ,in one form a plate1 a b1 of conducting surface is supported or poised horizontally below a second larger plate ,c1 also of conducting surface4 ,the poised plate is surrounded by a detached guard ring--an annular or perforated plate1 r g r' g'--exactly level and even with it as regards the upper surface4 ,the inner plate is carried by a delicate balance4 ,in use it is connected to one of the conductors and the lower plate to earth or to the other4 ,the attraction between them is determined by weighing4 ,by calculation the results can be made absolute1 as they depend on actual size of the plates and their distance1 outside of the potential difference of which of course nothing can be said4 ,if ,s is the area of the disc1 d the distance of the plates1 ,v-,v#a the difference of their potential1 which is to be measured1 and ,f the force required to balance their attraction1 we have3 ,f 7 7 ,v - ,v#a 7#b 99 ,s 7 _/ 7 #h 99 ,,pi 99 d#b 7 #bbc ,,standard ,,electrical ,,dictionary4 ,if ,v #j this reduces to ,f 7 ,v#b 99 ,s 7 _/ 7 #h 99 ,,pi 99 d#b 7 7#b7 or ,v d 99 ,square,root7 7#h 99 ,,pi 99 ,f 7 _/ ,s 7 7#c7 ,as ,f is expressed as a weight1 and ,s and a as measures of area and length1 this gives a means of directly obtaining potential values in absolute measure4 7,see ,idiostatic ,method--,heterostatic ,method47 ,synonyms--,attracted ,disc ,electrometer--,weight ,electrometer4 ,fig4 #aeb4 ,,section ,,of ,,base ,,of ,,portable ,,electrometer4 ,in some forms the movable disc is above the other1 and supported at the end of a balance beam4 ,in others a spring support1 arranged so as to enable the attraction to be determined in weight units1 is adopted4 ,the cuts1 ,figs4 #aeb and #aed1 show one of the latter type1 the portable electrometer4 ,the disc portion is contained within a cylindrical vessel4 ,fig4 #aec4 ,,diagram ,,illustrating ,,theory ,,of ,,absolute ,,electrometer4 ,referring to ,fig4 #aeb g is the stationary disc1 charged through the wire connection r2 f is the movable disc1 carried by a balance beam poised at i on a horizontal and transverse stretched platinum wire1 acting as a torsional spring4 ,the position of the end k of the balance beam shows when the disc f is in the plane of the guard ring h h4 ,the end k is forked horizontally and a horizontal sighting wire or hair is fastened across the opening of the fork4 ,when the hair is midway between two dots on a vertical scale the lever is in the sighted position1 as it is called1 and the disc is in the plane of the guard ring4 #bbd ,,standard ,,electrical ,,dictionary4 ,fig4 #aed4 ,,portable ,,electrometer4 ,the general construction is seen in ,fig4 #aed4 ,there the fixed disc ,d is carried by insulating stem g#a4 ,the charging electrode is supported by an insulating stem g#b1 and without contact with the box passes out of its cover through a guard tube ,e1 with cover1 sometimes called umbrella1 ,v4 ,the umbrella is to protect the apparatus from air currents4 ,at m is the sighting lens4 ,h is a lead box packed with pumice stone1 moistened with oil of vitriol or concentrated sulphuric acid1 to preserve the atmosphere dry4 ,before use the acid is boiled with some ammonium sulphate to expel any corrosive nitrogen oxides1 which might corrode the brass4 ,in use the upper disc is charged by its insulated electrode within the tube ,e2 the movable disc is charged if desired directly through the case of the instrument4 ,the upper disc is screwed up or down by the micrometer head ,m1 until the sighted position is reached4 ,the readings of the micrometer on the top of the case give the data for calculation4 #bbe ,,standard ,,electrical ,,dictionary4 ,fig4 #aee4 ,,lippman',s ,,capillary ,,electrometer4 ,electrometer1 ,capillary4 ,an electrometer for measuring potential difference by capillary action1 which latter is affected by electrostatic excitement4 ,a tube ,a contains mercury2 its end drawn out to a fine aperture dips into a vessel ,b which contains dilute sulphuric acid with mercury under it1 as shown4 ,wires running from the binding-posts a and b connect one with the mercury in ,a1 the other with that in ,b4 ,the upper end of the tube ,a connects with a thick rubber mercury reservoir ,t1 and manometer ,h4 ,the surface tension of the mercury-acid film at the lower end of the tube ,a keeps all in equilibrium4 ,if now a potential difference is established between a and b1 as by connecting a battery thereto1 the surface tension is increased and the mercury rises in the tube ,b4 ,by screwing down the compressing clamp ,e1 the mercury is brought back to its original position4 ,the microscope ,m is used to determine this position with accuracy4 ,the change in reading of the manometer gives the relation of change of surface tension and therefore of potential4 ,each electrometer needs special graduation or calibration1 but is exceedingly sensitive and accurate4 ,it cannot be used for greater potential differences than 4#f volt1 but can measure 4#jjjf volt4 ,its electrostatic capacity is so small that it can indicate rapid changes4 ,another form indicates potential difference by the movement of a drop of sulphuric acid in a horizontal glass tube1 otherwise filled with mercury1 and whose ends lead into two mercury cups or reservoirs4 ,the pair of electrodes to be tested are connected to the mercury vessels4 ,the drop moves towards the negative pole1 and its movement for small potential differences 7less than one volt7 is proportional to the electro-motive force or potential difference4 #bbf ,,standard ,,electrical ,,dictionary4 ,electrometer ,gauge4 ,an absolute electrometer 7see ,electrometer1 ,absolute7 forming an attachment to a ,thomson quadrant electrometer4 ,it is used to test the potential of the flat needle connected with the inner surface of the ,leyden jar condenser of the apparatus4 ,this it does by measuring the attraction between itself and an attracting disc1 the latter connected by a conductor with the interior of the jar4 ,electrometer1 ,lane's4 ,a ,leyden jar with mounted discharger1 so that when charged to a certain point it discharges itself4 ,it is connected with one coating of any jar whose charge is to be measured1 which jar is then charged by the other coating4 ,as the jar under trial becomes charged to a certain point the electrometer jar discharges itself1 and the number of discharges is the measure of the charge of the other jar4 ,it is really a unit jar1 q4 v4 ,fig4 #aef4 ,,thomson',s ,,quadrant ,,electrometer4 ,fig4 #aeg4 ,,henley',s ,,quadrant ,,electroscope4 #bbg ,,standard ,,electrical ,,dictionary4 ,electrometer1 ,quadrant4 7a7 ,sir ,william ,thomson's electrometer1 a simple form of which is shown in the cut1 consists of four quadrants of metal placed horizontally2 above these a broad flat aluminum needle hangs by a very fine wire1 acting as torsional suspension4 ,the quadrants are insulated from each other1 but the opposite ones connect with each other by wires4 ,the apparatus is adjusted so that1 when the quadrants are in an unexcited condition the needle is at rest over one of the diametrical divisions between quadrants4 ,the needle by its suspension wire is in communication with the interior of a ,leyden jar which is charged4 ,the whole is covered with a glass shade1 and the air within is kept dry by a dish of concentrated sulphuric acid so that the jar retains its charge for a long time and keeps the needle at approximately a constant potential4 ,if now two pairs of quadrants are excited with opposite electricities1 as when connected with the opposite poles of an insulated galvanic cell1 the needle is repelled by one pair and attracted by the other1 and therefore rotates through an arc of greater or less extent4 ,a small concave mirror is attached above the needle and its image is reflected on a graduated screen4 ,this makes the smallest movement visible4 ,sometimes the quadrants are double1 forming almost a complete box1 within which the needle moves4 7b7 ,henley's quadrant electrometer is for use on the prime conductor of an electric machine1 for roughly indicating the relative potential thereof4 ,it consists of a wooden standard attached perpendicularly to the conductor4 ,near one end is attached a semi-circular or quadrant arc of a circle graduated into degrees or angular divisions4 ,an index1 consisting of a straw with a pith-bell attached to its end hangs from the center of curvature of the arc4 ,when the prime conductor is charged the index moves up over the scale and its extent of motion indicates the potential relatively4 ,when the quadrant electrometer is spoken of it may always be assumed that ,sir ,william ,thomson's instrument is alluded to4 ,henley's instrument is properly termed a quadrant electroscope4 7,see ,electroscope47 ,electro-motive ,force4 ,the cause which produces currents of electricity4 ,in general it can be expressed in difference of potentials1 although the term electro-motive force should be restricted to potential difference causing a current4 ,it is often a sustained charging of the generator terminals whence the current is taken4 ,its dimensions are 7work done_/the quantity of electricity involved71 or 7 ,m 99 7,l#b7 _/7,t#b 7 7 _/ 77,m4#e7 99 7,l4#e77 7 7,m4#e7 99 7,l#a4e7 7 _/7,t#b7 ,the practical unit of electro-motive force is the volt1 q4 v4 ,it is often expressed in abbreviated form1 as ,e4 ,m4 ,d4 ,p41 or simply as ,d4 ,p41 i4 e41 potential difference4 ,electro-motive force and potential difference are in many cases virtually identical1 and distinctions drawn between them vary with different authors4 ,if we consider a closed electric circuit carrying a current1 a definite electro-motive force determined by ,ohm's law from the resistance and current obtains in it4 ,but if we attempt to define potential difference as proper to the circuit we may quite fail4 ,potential difference in a circuit is the difference in potential between defined points of such circuit4 ,but no points in a closed circuit can be found which differ in potential by an amount equal to the entire electro-motive force of the circuit4 ,potential difference is properly the measure of electro-motive force expended on the portion of a circuit between any given points4 ,electro-motive force of an entire circuit1 as it is measured1 as it were1 between two consecutive points but around the long portion of the circuit1 is not conceivable as merely potential difference4 ,taking the circle divided in to degrees as an analogy1 the electro-motive force of the entire circuit might be expressed as #cfj1 which are the degrees intervening between two consecutive points1 measured the long way around the circle4 ,but the potential difference between the same two points would be only #a1 for it would be measured by the nearest path4 ,transcriber's notes3 ,if #cfj is the long way1 #j is the short4 ,a formal restatement of the above definition of ,,emf3 ,if a charge ,q passes through a device and gains energy ,u1 the net ,,emf for that device is the energy gained per unit charge1 or ,u_/,q4 ,the unit of ,,emf is a volt1 or newton-meter per coulomb4 #bbh ,,standard ,,electrical ,,dictionary4 ,electro-motive ,force1 ,counter4 ,a current going through a circuit often has not only true or ohmic resistance to overcome1 but meets an opposing ,e4 ,m4 ,f4 ,this is termed counter-electro-motive force4 ,it is often treated in calculations as resistance1 and is termed spurious resistance4 ,it may be a part of the impedance of a circuit4 ,in a primary battery hydrogen accumulating on the negative plate develops counter ,e4 ,m4 ,f4 ,in the voltaic arc the differential heating of the two carbons does the same4 ,the storage battery is changed by a current passing in the opposite direction to its own natural current2 the polarity of such a battery is counter ,e4 ,m4 ,f4 ,electro-motive ,force1 ,unit4 ,unit electro-motive force is that which is created in a conductor moving through a magnetic field at such a rate as to cut one unit line of force per second4 ,it is that which must be maintained in a circuit of unit resistance to maintain a current of unit quantity therein4 ,it is that which must be maintained between the ends of a conductor in order that unit current may do unit work in a second4 ,electro-motive ,intensity4 ,the force acting upon a unit charge of electricity4 ,the mean force is equal to the difference of potential between two points within the field situated one centimeter apart1 such distance being measured along the lines of force4 ,the term is due to ,j4 ,clerk ,maxwell4 ,electro-motive ,series4 ,arrangement of the metals and carbon in series with the most electro-positive at one end1 and electronegative at the other end4 ,the following are examples for different exciting liquids3 ,dilute ,sulphuric ,dilute ,hydrochloric ,caustic ,potassium ,acid ,acid4 ,potash4 ,sulphide4 ,zinc ,zinc ,zinc ,zinc ,cadmium ,cadmium ,tin ,copper ,tin ,tin ,cadmium ,cadmium ,lead ,lead ,antimony ,tin ,iron ,iron ,lead ,silver ,nickel ,copper ,bismuth ,antimony ,bismuth ,bismuth ,iron ,lead ,antimony ,nickel ,copper ,bismuth ,copper ,silver ,nickel ,nickel ,silver ,antimony ,silver ,iron ,gold ,platinum ,carbon ,in each series the upper metal is the positive1 dissolved or attacked element4 #bbi ,,standard ,,electrical ,,dictionary4 ,electro-motograph4 ,an invention of ,thomas ,a4 ,edison4 ,a cylinder of chalk1 moistened with solution of caustic soda1 is mounted so as to be rotated by a handle4 ,a diaphragm has an arm connected to its center4 ,this arm is pressed against the surface of the cylinder by a spring4 ,when the cylinder is rotated1 a constant tension is exerted on the diaphragm4 ,if a current is passed through the junction of arm and cylinder the electrolytic action alters the friction so as to change the stress upon the diaphragm4 ,if the current producing this effect is of the type produced by the human voice through a microphone the successive variations in strain upon the diaphragm will cause it to emit articulate sounds4 ,these are produced directly by the movement of the cylinder1 the electrolytic action being rather the regulating portion of the operation4 ,hence very loud sounds can be produced by it4 ,this has given it the name of the loud- speaking telephone4 ,the same principle may be applied in other ways4 ,but the practical application of the motograph is in the telephone described4 ,fig4 #aeh4 ,,electro-,,motograph ,,telephone ,electro-motor4 ,this term is sometimes applied to a current generator1 such as a voltaic battery4 ,electro-muscular ,excitation4 ,a term in medical electricity indicating the excitation of muscle as the effect of electric currents of any kind4 ,electro-negative4 adj4 ,appertaining to negative electrification2 thus of the elements oxygen is the most electro-negative1 because if separated by electrolytic action from any combination1 it will be charged with negative electricity4 #bcj ,,standard ,,electrical ,,dictionary4 ,electro-optics4 ,the branch of natural science treating of the relations between light and electricity4 ,both are supposed to be phenomena of or due to the luminiferous ether4 ,to it may be referred the following3 7a7 ,electro-magnetic ,stress and ,magnetic ,rotary ,polarization2 7b7 ,dielectric ,strain2 all of which may be referred to in this book2 7c7 ,change in the resistance of a conductor by changes in light to which it is exposed 7see ,selenium72 7d7 ,the relation of the index of refraction of a dielectric to the dielectric constant 7see ,electro-magnetic ,theory of ,light72 7e7 ,the identity 7approximate7 of the velocity of light in centimeters and the relative values of the electrostatic and electro-magnet units of intensity1 the latter being #cj1jjj1jjj1jjj times greater than the former1 while the velocity of light is #cj1jjj1jjj1jjj centimeters per second4 ,electrophoric ,action4 ,the action of an electrophorous2 utilized in influence machines4 7,see ,electrophorous47 ,fig4 #aei4 ,,electrophorous4 ,electrophorous4 ,an apparatus for the production of electric charges of high potential by electrostatic induction1 q4 v4 ,it consists of a disc of insulating material ,b1 such as resin or gutta percha1 which is held in a shallow metal-lined box or form4 ,the disc may be half an inch thick and a foot or more in diameter1 or may be much smaller and thinner4 ,a metal disc ,a1 smaller in diameter is provided with an insulating handle which may be of glass1 or simply silk suspension strings4 ,to use it the disc ,b is excited by friction with a cat-skin or other suitable substance4 ,the metallic disc is then placed on the cake of resin exactly in its centre1 so that the latter disc or cake projects on all sides4 ,owing to roughness there is little real electric contact between the metal and dielectric4 ,on touching the metal disc a quantity of negative electricity escapes to the earth4 ,on raising it from the cake it comes off excited positively1 and gives a spark and is discharged4 ,it can be replaced1 touched1 removed and another spark can be taken from it1 and so on as long as the cake stays charged4 ,the successive discharges represent electrical energy expended4 ,this is derived from the muscular energy expended by the operator in separating the two discs when oppositely excited4 ,as generally used it is therefore an apparatus for converting muscular or mechanical energy into electric energy4 #bca ,,standard ,,electrical ,,dictionary4 ,electro-physiology4 ,the science of the electric phenomena of the animal system4 ,it may also be extended to include plants4 ,the great discovery of ,galvani with the frog's body fell into this branch of science4 ,the electric fishes1 gymnotus1 etc41 present intense phenomena in the same4 ,electroplating4 ,the deposition by electrolysis of a coating of metal upon a conducting surface4 ,the simplest system makes the object to be plated the negative electrode or plate in a galvanic couple4 ,thus a spoon or other object may be connected by a wire to a plate of zinc4 ,a porous cup is placed inside a battery jar4 ,the spoon is placed in the porous cup and the zinc outside it4 ,a solution of copper sulphate is placed in the porous cup1 and water with a little sodium or zinc sulphate dissolved in it1 outside4 ,a current starts through the couple1 and copper is deposited on the spoon4 ,a less primitive way is to use a separate battery as the source of current2 to connect to the positive plate by a wire the object to be plated1 and a plate of copper1 silver1 nickel or other metal to the other pole of the battery4 ,on immersing both object and plate 7anode7 in a bath of proper solution the object will become plated4 ,in general the anode is of the same material as the metal to be deposited1 and dissolving keeps up the strength of the bath4 ,there are a great many points of technicality involved which cannot be given here4 ,the surface of the immersed object must be conductive4 ,if not a fine wire network stretched over it will gradually fill up in the bath and give a matrix4 ,more generally the surface is made conductive by being brushed over with plumbago4 ,this may be followed by a dusting of iron dust1 followed by immersion in solution ot copper sulphate4 ,this has the effect of depositing metallic copper over the surface as a starter for the final coat4 ,attention must be paid to the perfect cleanliness of the objects1 to the condition of the bath1 purity of anodes and current density4 ,voltaic batteries are largely used for the current as well as special low resistance dynamos4 ,thermo-electric batteries are also used to some extent but not generally4 ,electro-pneumatic ,signals4 ,signals1 such as railroad signals or semaphores1 moved by compressed air1 which is controlled by valves operated by electricity4 ,the ,house telegraph1 which was worked by air controlled by electricity1 might come under this term1 but it is always understood as applied to railroad signals1 or their equivalent4 #bcb ,,standard ,,electrical ,,dictionary4 ,electropoion ,fluid4 ,an acid depolarizing solution for use in zinc-carbon couples1 such as the ,grenet battery4 ,the following are formulae for its preparation3 7a7 ,dissolve one pound of potassium bichromate in ten pounds of water1 to which two and one-half pounds of concentrated sulphuric acid have been gradually added4 ,the better way is to use powdered potassium bichromate1 add it to the water first1 and then gradually add the sulphuric acid with constant stirring4 7b7 ,to three pints of water add five fluid ounces of concentrated sulphuric acid2 add six ounces pulverized potassium bichromate4 7c7 ,mix one gallon concentrated sulphuric acid and three gallons of water4 ,in a separate vessel dissolve six pounds potassium bichromate in two gallons of boiling water4 ,mix the two4 ,the last is the best formula4 ,always use electropoion fluid cold4 7,see ,trouv's ,solution--,poggendorff's ,solution--,kakogey's ,solution-- ,tissandrier's ,solution--,chutaux's ,solution47 ,electro-positive4 adj4 ,appertaining to positive electrification2 thus potassium is the most electro-positive of the elements4 7,see ,electro-negative47 ,electro-puncture4 ,the introduction into the system of a platinum point or needle1 insulated with vulcanite1 except near its point1 and connected as the anode of a galvanic battery4 ,the kathode is a metal one1 covered with a wet sponge and applied on the surface near the place of puncture4 ,it is used for treatment of aneurisms or diseased growths1 and also for removal of hair by electrolysis4 7,see ,hair1 ,removal of by ,electrolysis47 ,synonym--,galvano-puncture4 ,electro-receptive4 adj4 ,a term applied to any device or apparatus designed to receive and absorb electric energy4 ,a motor is an example of an electro-receptive mechanism4 ,electroscope4 ,an apparatus for indicating the presence of an electric charge1 and also for determining the sign1 or whether the charge is positive or negative4 ,the simplest form consists of a thread doubled at its centre and hung therefrom4 ,on being charged1 or on being connected to a charged body the threads diverge4 ,a pair of pith balls may be suspended in a similar way1 or a couple of strips of gold leaf within a flask 7the gold leaf electroscope74 ,to use an electroscope to determine the sign of the charge it is first slightly charged4 ,the body to be tested is then applied to the point of suspension1 or other charging point4 ,if at once further repelled the charge of the body is of the same sign as the slight charge first imparted to the electroscope leaves2 the leaves as they become more excited will at once diverge more4 ,if of different sign they will at first approach as their charge is neutralized and will afterwards diverge4 ,the gold-leaf electroscope is generally enclosed in a glass bell jar or flask4 ,sometimes a pair of posts rise1 one on each side1 to supply points of induction from the earth to intensify the action4 7,see ,electrometer1 ,quadrant--,electroscope1 ,gold leaf1 and others47 #bcc ,,standard ,,electrical ,,dictionary4 ,electroscope1 ,bennett's4 ,a gold-leaf electroscope1 the suspended leaves of which are contained in a glass shade or vessel of dry air4 ,on the inside of the glass shade are two strips of gold leaf1 which rise from the lower edge a short distance1 being pasted to the glass1 and connected to the ground4 ,these act by induction to increase the sensitiveness of the instruments4 ,electroscope1 ,bohenberger's4 ,a condensing electroscope 7see ,electroscope1 ,condensing7 with a single strip of gold leaf suspended within the glass bell4 ,this is at an equal distance from the opposite poles of two dry piles 7see ,zamboni's ,dry ,pile7 standing on end1 one on each side of it4 ,as soon as the leaf is excited it moves toward one and away from the other pile1 and the sign of its electrification is shown by the direction of its motion4 ,electroscope1 ,condensing4 ,a gold leaf electroscope1 the glass bell of which is surmounted by an electrophorous or static condenser1 to the lower plate of which the leaves of gold are suspended or connected4 ,in use the object to be tested is touched to the lower plate1 and the upper plate at the same time is touched by the finger4 ,the plates are now separated4 ,this reduces the capacity of the lower plate greatly and its charge acquires sufficient potential to affect the leaves1 although the simple touching may not have affected them at all4 ,electroscope1 ,gold ,leaf4 ,an electroscope consisting of two leaves of gold leaf hung in contact with each other from the end of a conductor4 ,when excited they diverge4 ,the leaves are enclosed in a glass vessel4 ,fig4 #afj4 ,,gold ,,leaf ,,electroscope4 #bcd ,,standard ,,electrical ,,dictionary4 ,electroscope1 ,pith ,ball4 ,two pith balls suspended at opposite ends of a silk thread doubled in the middle4 ,when charged with like electricity they repel each other4 ,the extent of their repulsion indicates the potential of their charge4 ,electrostatic ,attraction and ,repulsion4 ,the attraction and repulsion of electrostatically charged bodies for each other1 shown when charged with electricity4 ,if charged with electricity of the same sign they repel each other4 ,if with opposite they attract each other4 ,the classic attraction and subsequent repulsion of bits of straw and chaff by the excited piece of amber is a case of electrostatic attraction and repulsion4 7,see ,electricity1 ,static--,electrostatics--,coulomb's ,laws of ,electrostatic ,attraction and ,repulsion47 ,electrostatic ,induction1 ,coefficient of4 ,the coefficient expressing the ratio of the charge or change of charge developed in one body to the potential of the inducing body4 ,electrostatic ,lines of ,force4 ,lines of force assumed to exist in an electrostatic field of force1 and to constitute the same4 ,in general they correspond in action and attributes with elcctro-magnetic lines of force4 ,they involve in almost all cases either a continuous circuit1 or a termination at both ends in oppositely charged surfaces4 ,fig4 #afa4 ,,electrostatic ,,lines ,,of ,,force ,,between ,,near ,,surfaces4 ,fig4 #afb4 ,,electrostatic ,,links ,,of ,,force ,,between ,,distant ,,surfaces4 #bce ,,standard ,,electrical ,,dictionary4 ,the cut1 ,fig4 #afa1 shows the general course taken by lines of force between two excited surfaces when near together4 ,here most of them are straight lines reaching straight across from surface to surface1 while a few of them arch across from near the edges1 tending to spread4 ,if the bodies are drawn apart the spreading tendency increases and the condition of things shown in the next cut1 ,fig4 #afb1 obtains4 ,there is an axial line whose prolongations may be supposed to extend indefinitely1 as occupying a position of unstable equilibrium4 ,here the existence of a straight and unterminated line of force may be assumed4 ,a direction is predicated to lines of force corresponding with the direction of an electric current4 ,they are assumed to start from a positively charged and to go towards a negatively charged surface4 ,a positively charged body placed in an electrostatic field of force will be repelled from the region of positive into or towards the region of negative potential following the direction of the lines of force1 not moving transversely to them1 and having no transverse component in its motion4 ,transcriber's note3 ,more precisely1 ,a positively charged body placed in an electrostatic field of force will be repelled from the region of positive into or towards the region of negative potential ,,accelerating in the direction of the lines of force1 not ,,accelerating transversely to them1 and having no transverse component in its ,,acceleration4 ,previously acquired momentum can produce a transverse component of ,,velocity4 ,electrostatics4 ,the division of electric science treating of the phenomena of electric charge1 or of electricity in repose1 as contrasted with electro-dynamics or electricity in motion or in current form4 ,charges of like sign repel1 and of unlike sign attract each other4 ,the general inductive action is explained by the use of the electrostatic field of force and electrostatic lines of force1 q4 v4 ,the force of attraction and repulsion of small bodies or virtual points1 which are near enough to each other1 vary as the square of the distance nearly1 and with the product of the quantities of the charges of the two bodies4 ,electrostatic ,refraction4 ,dr4 ,kerr found that certain dielectrics exposed to electric strain by being placed between two oppositely excited poles of a ,holtz machine or other source of very high tension possess double refracting powers1 in other words can rotate a beam of polarized light1 or can develop two complimentary beams from common light4 ,bisulphide of carbon shows the phenomenon well1 acting as glass would if the glass were stretched in the direction of the electrostatic lines of force4 ,to try it with glass1 holes are drilled in a plate and wires from an influence machine are inserted therein4 ,the discharge being maintained through the glass it polarizes light4 ,synonym--,kerr ,effect4 ,electrostatic ,series4 ,a table of substances arranged in the order in which they are electrostatically charged by contact1 generally by rubbing against each other4 ,the following series is due to ,faraday4 ,the first members become positively excited when rubbed with any of the following members1 and vice versa4 ,the first elements correspond to the carbon plate in a galvanic battery1 the succeeding elements to the zinc plate4 ,cat1 and ,bear-skin--,flannel--,ivory--,feathers- -,rock ,crystal--,flint ,glass--,cotton--,linen--,canvas--,white ,silk--the ,hand--,wood--,shellac--the ,metals 7,iron-,copper-,brass-,tin-,silver-,plat inum7--,sulphur4 ,there are some irregularities4 ,a feather lightly drawn over canvas is negatively electrified2 if drawn through folds pressed against it it is positively excited4 ,many other exceptions exist1 so that the table is of little value4 #bcf ,,standard ,,electrical ,,dictionary4 ,electrostatic ,stress4 ,the stress produced upon a transparent medium in an electrostatic field of force by which it acquires double refracting or polarizing properties as regards the action of such medium upon light4 7,see ,electrostatic ,refraction47 ,electro-therapeutics or ,therapy4 ,the science treating of the effects of electricity upon the animal system in the treatment and diagnosis of disease4 ,electrotonus4 ,an altered condition of functional activity occurring in a nerve subjected to the passage of an electric current4 ,if the activity is decreased1 which occurs near the anode1 the state is one of anelectrotonus1 if the activity is increased which occurs near the kathode the condition is one of kathelectrotonus4 ,electrotype4 ,the reproduction of a form of type or of an engraving or of the like by electroplating1 for printing purposes4 ,the form of type is pressed upon a surface of wax contained in a shallow box4 ,the wax is mixed with plumbago1 and if necessary some more is dusted and brushed over its surface and some iron dust is sprinkled over it also4 ,a matrix or impression of the type is thus obtained1 on which copper is deposited by electroplating1 q4 v4 ,element1 ,chemical4 ,the original forms of matter that cannot be separated into constituents by any known process4 ,they are about seventy in number4 ,some of the rarer ones are being added to or cancelled with the progress of chemical discovery4 ,for their electric relations see ,electro-chemical ,equivalents--,electro-chemical ,series4 ,the elements in entering into combination satisfy chemical affinity and liberate energy1 which may take the form of electric energy as in the galvanic battery1 or of heat energy1 as in the combustion of carbon or magnesium4 ,therefore an uncombined element is the seat of potential energy4 7,see ,energy1 ,potential47 ,in combining the elements always combine in definite proportions4 ,a series of numbers1 one being proper to each element which denote the smallest common multipliers of these proportions1 are called equivalents4 ,taking the theory of valency into consideration the product of the equivalents by the valencies gives the atomic weights4 #bcg ,,standard ,,electrical ,,dictionary4 ,element1 ,mathematical4 ,a very small part of anything1 corresponding in a general way to a differential1 as the element of a current4 ,element of a ,battery ,cell4 ,the plates in a galvanic couple are termed elements1 as the carbon and zinc plates in a ,bunsen cell4 ,the plate unattacked by the solution1 as the carbon plate in the above battery1 is termed the negative plate or element2 the one attacked1 as the zinc plate1 is termed the positive plate or element4 ,synonym--,voltaic ,element4 ,elements1 ,electrical ,classification of4 ,this may refer to ,electro-chemical ,series1 ,electrostatic ,series1 or ,thermo-electric ,series1 all of which may be referred to4 ,element1 ,thermo-electric4 ,one of the metals or other conductors making a thermo-electric couple1 the heating of whose junction produces electro-motive force and a current1 if on closed circuit4 ,the elements of a couple are respectively positive and negative1 and most conductors can be arranged in a series according to their relative polarity4 7,see ,thermo-electric ,series47 ,elongation4 ,the throw of the magnetic needle4 7,see ,throw47 ,synonym--,throw4 ,embosser1 ,telegraph4 ,a telegraphic receiver giving raised characters on a piece of paper4 ,it generally refers to an apparatus of the old ,morse receiver type1 one using a dry point stylus1 which pressing the paper into a groove in the roller above the paper1 gave raised characters in dots and lines4 ,fig4 #afc4 ,,morse ,,receiver4 #bch ,,standard ,,electrical ,,dictionary4 ,e4 ,m4 ,d4 ,p4 ,abbreviation for electro-motive difference of potential or for electro-motive force producing a current as distinguished from mere inert potential difference4 ,e4 ,m4 ,f4 ,abbreviation for electro-motive force4 ,fig4 #afd4 ,,end-,,on ,,method4 ,end-on ,method4 ,a method of determining the magnetic moment of a magnet4 ,the magnet under examination1 ,n ,s1 is placed at right angles to the magnetic meridian1 ,m ,o ,r1 and pointing directly at or end on to the centre of a compass needle1 n s4 ,from the deflection a of the latter the moment is calculated4 ,endosmose1 ,electric4 ,the inflowing current of electric osmose4 7,see ,osmose1 ,electric47 ,end ,play4 ,the power to move horizontally in its bearings sometimes given to armature shafts4 ,this secures a more even wearing of the commutator faces4 ,end play is not permissible in disc armatures1 as the attraction of the field upon the face of the armature core would displace it endwise4 ,for such armatures thrust-bearings preventing end play have to be provided4 ,energy4 ,the capacity for doing work4 ,it is measured by work units which involve the exercise of force along a path of some length4 ,a foot-pound1 centimeter-gram1 and centimeter-dyne are units of energy and work4 ,the absolute unit of energy is the erg1 a force of one dyne exercised over one centimeter of space4 7,see ,dyne47 ,the dimensions of energy are force 7,m 99 ,l _/ ,t#b7 99 space 7,l7 ,m 99 7,l#b _/ ,t#b74 ,energy may be chemical 7atomic or molecular71 mechanical1 electrical1 thermal1 physical1 potential1 kinetic1 or actual1 and other divisions could be formulated4 #bci ,,standard ,,electrical ,,dictionary4 ,energy1 ,atomic4 ,the potential energy due to atomic relations set free by atomic change2 a form of chemical energy1 because chemistry refers to molecular as well as to atomic changes4 ,when atomic energy loses the potential form it immediately manifests itself in some other form1 such as heat or electric energy4 ,it may be considered as always being potential energy4 7,see ,energy1 ,chemical47 ,transcriber's note3 ,this item refers to chemical energy1 that is manifest in work done by electric forces during re-arrangement of electrons4 ,atomic energy now refers to re-arrangement of nucleons 7protons and neutrons7 and the resulting conversion of mass into energy4 ,energy1 ,chemical4 ,a form of potential energy 7see ,energy1 ,potential7 possessed by elements in virtue of their power of combining with liberation of energy1 as in the combination of carbon with oxygen in a furnace2 or by compounds in virtue of their power of entering into other combinations more satisfying to the affinities of their respective elements or to their own molecular affinity4 ,thus in a galvanic couple water is decomposed with absorption of energy1 but its oxygen combines with zinc with evolution of greater amount of energy1 so that in a voltaic couple the net result is the setting free of chemical energy1 which is at once converted into electrical energy in current form1 if the battery is on a closed circuit4 ,energy1 ,conservation of4 ,a doctrine accepted as true that the sum of energy in the universe is fixed and invariable4 ,this precludes the possibility of perpetual motion4 ,energy may be unavailable to man1 and in the universe the available energy is continually decreasing1 but the total energy is the same and never changes4 ,transcriber's note3 ,if mass is counted a energy 7,em997c#b77 then energy is strictly conserved4 ,energy1 ,degradation of4 ,the reduction of energy to forms in which it cannot be utilized by man4 ,it involves the reduction of potential energy to kinetic energy1 and the reduction of kinetic energy of different degrees to energy of the same degree4 ,thus when the whole universe shall have attained the same temperature its energy will have become degraded or non-available4 ,at present in the sun we have a source of kinetic energy of high degree1 in coal a source of potential energy4 ,the burning of all the coal will be an example of the reduction of potential to kinetic energy1 and the cooling of the sun will illustrate the lowering in degree of kinetic energy4 7,see ,energy1 ,conservation of--,energy1 ,potential--,energy1 ,kinetic47 ,energy1 ,electric4 ,the capacity for doing work possessed by electricity under proper conditions4 ,electric energy may be either kinetic or potential4 ,as ordinary mechanical energy is a product of force and space1 so electric energy is a product of potential difference and quantity4 ,thus a given number of coulombs of electricity in falling a given number of volts develop electric energy4 ,the dimensions are found therefore by multiplying electric current intensity quantity 77,m4#e7 99 7,l4#e771 by electric potential 77,m4#e7997,l#a4e7 _/ 7,t#b771 giving 7,m 99 7,l#b7_/7,t#b771 the dimensions of energy in general as it should be4 ,the absolute unit of electric energy in electro-magnetic measure is 7#a;,e-#g7 volt coulombs4 #bdj ,,standard ,,electrical ,,dictionary4 ,the practical unit is the volt-coulomb4 ,as the volt is equal to #a;,e#h absolute units of potential and the coulomb to #j4a absolute units of quantity1 the volt-coulomb is equal to #a;,e#g absolute units of energy4 ,the volt-coulomb is very seldom used1 and the unit of ,electric ,activity or ,power 7see ,power1 ,electric71 the volt-ampere1 is universally used4 ,this unit is sometimes called the ,watt1 q4 v41 and it indicates the rate of expenditure or of production of electric energy4 ,the storing up in a static accumulator or condenser of a given charge of electricity1 available for use with a given change of potential represents potential electric energy4 ,the passing of a given quantity through a conductor with a given fall of potential represents kinetic electric energy4 ,in a secondary battery there is no storage of energy1 but the charging current simply accumulates potential chemical energy in the battery1 which chemical energy is converted into electric energy in the discharge or delivery of the battery4 ,it is customary to discuss ,ohm's law in this connection2 it is properly treated under ,electric ,power1 to which the reader is referred4 7,see ,power1 ,electric47 ,transcriber's note3 ,a volt-ampere or watt is a unit of power4 ,a volt-coulomb second or watt-second is a unit of energy4 ,power multiplied by time yields energy4 ,energy1 ,electric ,transmission of4 ,if an electric current passes through a conductor all its energy is expended in the full circuit4 ,part of the circuit may be an electrical generator that supplies energy as fast as expended4 ,part of the circuit may be a motor which absorbs part of the energy1 the rest being expended in forcing a current through the connecting wires and through the generator4 ,the electric energy in the generator and connecting wires is uselessly expended by conversion into heat4 ,that in the motor in great part is utilized by conversion into mechanical energy which can do useful work4 ,this represents the transmission of energy4 ,every electric current system represents this operation1 but the term is usually restricted to the transmission of comparatively large quantities of energy4 ,a typical installation might be represented thus4 ,at a waterfall a turbine water wheel is established which drives a dynamo4 ,from the dynamo wires are carried to a distant factory1 where a motor or several motors are established1 which receive current from the dynamo and drive the machinery4 ,the same current1 if there is enough energy1 may be used for running lamps or electroplating4 ,as electric energy 7see ,energy1 ,electric17 is measured by the product of potential difference by quantity1 a very small wire will suffice for the transmission of a small current at a high potential1 giving a comparatively large quantity of energy4 ,it is calculated that the energy of ,niagara ,falls could be transmitted through a circuit of iron telegraph wire a distance of over #a1jjj miles1 but a potential difference of #ace1jjj1jjj volts would be required1 something quite impossible to obtain or manage4 ,transcriber's note3 ,contemporary long distance power transmission lines use #aae1jjj to #a1bjj1jjj volts4 ,at higher voltages corona discharges 7arcing7 create unacceptable losses4 #bda ,,standard ,,electrical ,,dictionary4 ,energy1 ,kinetic4 ,energy due to matter being actually in motion4 ,it is sometimes called actual energy4 ,the energy varies directly with the mass and with the square of the velocity4 ,it is represented in formula by 4#e 99,m 99 7v#b74 ,synonyms--,actual ,energy--,energy of ,motion--,dynamic ,energy4 ,energy1 ,mechanical4 ,the energy due to mechanical change or motion1 virtually the same as molar energy4 7,see ,energy1 ,molar47 ,energy1 ,molar4 ,the energy of masses of matter due to movements of or positions of matter in masses2 such as the kinetic energy of a pound or of a ton in motion1 or the potential energy of a pound at an elevation of one hundred feet4 ,energy1 ,molecular4 ,the potential energy due to the relations of molecules and set free by their change in the way of combination4 ,it is potential for the same reason that applies to atomic and chemical energy1 of which latter it is often a form1 although it is often physical energy4 ,the potential energy stored up in vaporization is physical and molecular energy2 the potential energy stored up in uncombined potassium oxide and water1 or calcium oxide 7quicklime7 and water is molecular1 and when either two substances are brought together kinetic1 thermal or heat energy is set free1 as in slaking lime for mortar4 ,energy of an ,electrified ,body4 ,an electrified body implies the other two elements of a condenser4 ,it is the seat of energy set free when discharged4 7,see ,dielectric1 ,energy of47 ,the two oppositely charged bodies tend to approach4 ,this tendency1 together with the distances separating them1 represents a potential energy4 ,energy of ,stress4 ,potential energy due to stress1 as the stretching of a spring4 ,this is hardly a form of potential energy4 ,a stressed spring is merely in a position to do work at the expense of its own thermal or kinetic energy because it is cooled in doing work4 ,if it possessed true potential energy of stress it would not be so cooled4 ,energy of ,position4 ,potential energy due to position1 as the potential energy of a pound weight raised ten feet 7ten foot lbs474 7,see ,energy1 ,potential47 ,energy1 ,physical4 ,the potential energy stored up in physical position or set free in physical change4 ,thus a vapor or gas absorbs energy in its vaporization1 which is potential energy1 and appears as heat energy when the vapor liquefies4 #bdb ,,standard ,,electrical ,,dictionary4 ,energy1 ,potential1 or ,static ,energy4 ,the capacity for doing work in a system due to advantage of position or other cause1 such as the stress of a spring4 ,a pound weight supported ten feet above a plane has ten foot lbs4 of potential energy of position referred to that plane4 ,a given weight of an elementary substance represents potential chemical energy1 which will be liberated as actual energy in its combination with some other element for which it has an affinity4 ,thus a ton of coal represents a quantity of potential chemical energy which appears in the kinetic form of thermal energy when the coal is burning in a furnace4 ,a charged ,leyden jar represents a source of potential electric energy1 which becomes kinetic heat energy as the same is discharged4 ,energy1 ,thermal4 ,a form of kinetic molecular energy due to the molecular motion of bodies caused by heat4 ,entropy4 ,non-available energy4 ,as energy may in some way or other be generally reduced to heat1 it will be found that the equalizing of temperature1 actual and potential1 in a system1 while it leaves the total energy unchanged1 makes it all unavailable1 because all work represents a fall in degree of energy or a fall in temperature4 ,but in a system such as described no such fall could occur1 therefore no work could be done4 ,the universe is obviously tending in that direction4 ,on the earth the exhaustion of coal is in the direction of degradation of its high potential energy1 so that the entropy of the universe tends to zero4 7,see ,energy1 ,degradation of47 ,transcriber's note3 ,entropy 7disorder7 ,,increases1 while ,,available ,,energy tends to zero4 ,entropy1 ,electric4 ,clerk ,maxwell thought it possible to recognize in the ,peltier effect1 q4 v41 a change in entropy1 a gain or loss according to whether the thermo-electric junction was heated or cooled4 ,this is termed ,electric ,entropy4 7,see ,energy1 ,degradation of47 #bdc ,,standard ,,electrical ,,dictionary4 ,fig4 #afe4 ,,epinus' ,,condenser1 ,epinus' ,condenser4 ,two circular brass plates1 ,a and ,b1 are mounted on insulating supports1 and arranged to be moved towards or away from each other as desired4 ,between them is a plate of glass1 ,c1 or other dielectric4 ,pith balls may be suspended back of each brass plate as shown4 ,the apparatus is charged by connecting one plate to an electric machine and the other to the earth4 ,the capacity of the plate connected to the machine is increased by bringing near to it the grounded plate1 by virtue of the principle of bound charges4 ,this apparatus is used to illustrate the principles of the electric condenser4 ,it was invented after the ,leyden jar was invented4 ,fig4 #aff4 ,,epinus' ,,condenser4 ,e4 ,p4 ,s4 ,initials of ,electrical ,power ,storage2 applied to a type of secondary battery made by a company bearing that title4 ,fig4 #afg4 ,,cam ,,equalizer4 #bdd ,,standard ,,electrical ,,dictionary4 ,equalizer4 ,in electro-magnetic mechanism an arrangement for converting the pull of the electro-magnet varying in intensity greatly over its range of action1 into a pull of sensibly equal strength throughout4 ,the use of a rocking lever acting as a cam1 with leverage varying as the armature approaches or recedes from the magnet core is one method of effecting the result4 ,such is shown in the cut4 ,e is an electro-magnet1 with armature a4 ,a and ,b are the equalizer cams4 ,the pull on the short end of the cam ,b is sensibly equal for its whole length4 ,many other methods have been devised1 involving different shapes of pole pieces1 armatures or mechanical devices other than the one just shown4 ,equipotential4 adj4 ,equal in potential2 generally applied to surfaces4 ,thus every magnetic field is assumed to be made up of lines of force and intersecting those lines1 surfaces1 plane1 or more or less curved in contour1 can be determined1 over all parts of each one of which the magnetic intensity will be identical4 ,each surface is the locus of equal intensity4 ,the same type of surface can be constructed for any field of force1 such as an electrostatic field1 and is termed an equipotential surface4 ,equipotential ,surface1 ,electrostatic4 ,a surface in an electrostatic field of force1 which is the locus of all points of a given potential in such field2 a surface cutting all the lines of force at a point of identical potential4 ,lines of force are cut perpendicularly by an equipotential surface1 or are normal thereto4 ,equipotential ,surface1 ,magnetic and ,electro-magnetic4 ,a surface bearing the same relation to a magnetic or electro-magnetic field of force that an electrostatic equipotential surface 7see ,equipotential ,surface1 ,electrostatic17 does to an electrostatic field of force4 ,equivalent1 ,chemical4 ,the quotient obtained by dividing the atomic weight of an element by its valency4 ,equivalents1 ,electro-chemical4 ,the weight of any substance set free by one coulomb of electricity4 ,the following give some equivalents expressed in milligrams3 ,hydrogen 4#jaje ,mercury 7mercurous7 #b4aj ,gold 4#fhgg ,iron 7ferric7 4#aifd ,silver #a4acd ,iron 7ferrous7 4#bid ,copper 7cupric7 4#ccjg ,nickel 4#cjih ,mercury 7mercuric7 #a4je ,zinc 4#cdac ,lead #a4jhfh ,chlorine 4#cgbh ,oxygen 4#hi #bde ,,standard ,,electrical ,,dictionary4 ,equivalent1 ,electro-mechanical4 ,the work or energy equivalent to unit quantities of electric energy1 q4 v42 or equivalent to a unit current in a conductor whose ends differ one unit of potential4 ,the unit of electric energy taken is the watt-second or volt-coulomb4 ,one volt-coulomb is equal to ,ergs #a;,e#g #ajjjjjjj ,foot ,pound 4#gcgccg ,gram-degree ,c4 4#bdjfh ,horse ,power ,second 4#jjacdjf ,pound-degree ,f4 4#jjjiee ,one horse power is equal to #gde4idc volt coulombs per second4 ,equivalent1 ,electro-thermal4 ,the heat produced by a unit current passing through a conductor with unit difference of potential at its ends2 the heat equivalent of a volt-coulomb or watt-second4 ,it is equal to ,gram-degree ,c4 4#bdjfh ,pound-degree ,f4 4#jjjiee ,equivalent1 ,thermo-chemical4 ,the calories evolved by the combination of one gram of any substance with its equivalent of another substance being determined1 the product obtained by multiplying this number by the equivalent 7atomic or molecular weight _/ valency7 of the first element or substance is the thermo-chemical equivalent4 ,if expressed in kilogram calories1 the product of the thermo-chemical equivalent by #j4dc gives the voltage required to effect such decomposition4 ,the following are thermo-chemical equivalents of a few combinations3 ,water #cd4e ,zinc oxide #dc4b ,iron protoxide #cd4e ,iron ,sesquioxide #ca4i ,x #c ,copper oxide #ai4b ,equivolt4 ,the mechanical energy of one volt electro-motive force exerted under unit conditions through one equivalent of chemical action in grains4 7,j4 ,t4 ,sprague47 ,this unit is not in general use as the unit of electric energy1 the volt-coulomb and 7for rate of electric energy7 the volt-ampere being always used4 ,erg4 ,the absolute or fundamental ,c4 ,g4 ,s4 unit of work or energy4 ,the work done or energy expended in moving a body through one centimeter against a resistance of one dyne4 ,erg-ten4 ,ten millions of ergs1 or ten meg-ergs4 ,escape4 ,a term applied to leakage of current4 ,etching1 ,electric4 ,a process of producing an etched plate4 ,the plate is coated with wax1 and the design traced through as in common etching4 ,it is then placed in a bath and is connected to the positive terminal from a generator1 whose negative is immersed in the same bath1 so that the metal is dissolved by electrolytic action4 ,by attaching to the other terminal and using a plating bath1 a rough relief plate may be secured1 by deposition in the lines of metal by electroplating4 ,synonym--,electric ,engraving4 #bdf ,,standard ,,electrical ,,dictionary4 ,ether4 ,the ether is a hypothetical thing that was invented to explain the phenomena of light4 ,light is theoretically due to transverse vibrations of the ether4 ,since the days of ,young the conception of the ether has extended1 and now light1 radiant heat1 and electricity are all treated as phenomena of the ether4 ,electrical attraction and repulsion are explained by considering them due to local stresses in the ether2 magnetic phenomena as due to local whirlpools therein4 ,the ether was originally called the luminiferous ether1 but the adjective should now be dropped4 ,its density is put at #icf;,e-#ba that of water1 or equal to that of the atmosphere at #baj miles above the earth's surface4 ,its rigidity is about #a;,e-#i that of steel 7see ,ten1 ,powers of72 as a whole it is comparable to an all-pervading jelly1 with almost perfect elasticity4 ,the most complete vacuum is filled with ether4 ,all this is a hypothesis1 for the ether has never been proved to exist4 ,whether gravitation will ever be explained by ,it remains to be seen4 ,transcriber's note3 ,the ,michelson-,morley experiment in #ahhg 7five years before this book7 cast serious doubt on the ether4 ,in #aije ,einstein explained electromagnetic phenomenon with photons4 ,in #aifc ,edward ,m4 ,purcell used special relativity to derive the existence of magnetism and radiation4 ,eudiometer4 ,a graduated glass tube for measuring the volumes of gases4 ,in its simplest form it is simply a cylindrical tube1 with a scale etched or engraved upon it1 closed at one end and open at the other4 ,the gas to be measured is collected in it over a liquid1 generally water1 dilute sulphuric acid in the gas voltameter1 or mercury4 ,many different shapes have been given them by ,hoffmann1 ,ure1 ,bunsen and others4 ,evaporation1 ,electric4 ,the superficial sublimation or evaporation of a substance under the influence of negative electricity4 ,it is one of the effects investigated by ,crookes in his experiments with high vacua4 ,he found that when a metal1 even so infusible as platinum1 was exposed to negative electrification in one of his high vacuum tubes1 that it was volatilized perceptibly4 ,a cadmium electrode heated and electrified negatively was found to give a strong coating of metal on the walls of the tube4 ,even in the open air the evaporation of water was found to be accelerated by negative electrification4 ,exchange1 ,telephone4 ,the office to which telephone wires lead in a general telephone system4 ,in the office by a multiple switch board1 or other means1 the different telephones are interconnected by the office attendants1 so that any customers who desire it may be put into communication with each other4 ,the exchange is often termed the ,central ,office1 although it may be only a branch office4 ,excitability1 ,faradic4 ,the action produced in nerve or muscle of the animal system by an alternating or intermitting high potential discharge from an induction coil4 #bdg ,,standard ,,electrical ,,dictionary4 ,excitability1 ,galvanic4 ,the same as ,faradic excitability1 except that it refers to the effects of the current from a galvanic battery4 ,excitability of ,animal ,system1 ,electric4 ,the susceptibility of a nerve or muscle to electric current shown by the effect produced by its application4 ,exciter4 ,a generator used for exciting the field magnet of a dynamo4 ,in alternating current dynamos1 e4 g41 of the ,westinghouse type1 a special dynamo is used simply to excite the field magnet4 ,in central station distribution the same is often done for direct current dynamos4 ,exosmose1 ,electric4 ,the outflowing current of electric osmose4 7,see ,osmose1 ,electric47 ,expansion1 ,coefficient of4 ,the number expressing the proportional increase in size1 either length1 area or volume1 of a substance under the influence generally of heat4 ,there are three sets of coefficients1 7#a7 of linear expansion1 7#b7 of superficial expansion1 7#c7 of cubic expansion or expansion of volume4 ,the first and third are the only ones much used4 ,they vary for different substances1 and for the same substance at different temperatures4 ,they are usually expressed as decimals indicating the mixed number referred to the length or volume of the body at the freezing point as unity4 ,expansion1 ,electric4 7a7 ,the increase in volume of a condenser1 when charged electrostatically4 ,a ,leyden jar expands when charged1 and contracts when discharged4 7b7 ,the increase in length of a bar of iron when magnetized4 ,this is more properly called magnetic expansion or magnetic elongation4 ,exploder4 7a7 ,a small magneto-generator for producing a current for heating the wire in an electric fuse of the ,abel type 7see ,fuse1 ,electric71 and thereby determining an explosion4 7b7 ,the term may also be applied to a small frictional or influence machine for producing a spark for exploding a spark fuse4 ,explorer4 ,a coil1 similar to a magnetizing coil 7see ,coil1 ,magnetizing71 used for investigating the electro-magnetic circuit and for similar purposes4 ,if placed around an electro-magnet and connected with a galvanometer1 it will produce a deflection1 owing to a momentary induced current1 upon any change in the magnet1 such as removing or replacing the armature4 ,it is useful in determining the leakage of lines of force and for general investigations of that nature4 ,it is often called an exploring coil4 ,hughes' ,induction ,balance 7see ,induction ,balance1 ,hughes'7 is sometimes called a ,magnetic ,explorer4 ,the exploring coil may be put in circuit with a galvanometer for quantitative measurements or with a telephone for qualitative ones4 #bdh ,,standard ,,electrical ,,dictionary4 ,extension ,bell ,call4 ,a system of relay connection1 q4 v41 by which a bell is made to continue ringing after the current has ceased coming over the main line4 ,it is designed to prolong the alarm given by a magneto call bell1 q4 v41 which latter only rings as long as the magneto handle is turned4 ,a vibrating electric bell 7see ,bell1 ,electric17 is connected in circuit with a local battery and a switch normally open1 but so constructed as to close the circuit when a current is passed and continue to do so indefinitely4 ,the distant circuit is connected to this switch4 ,when the magneto is worked it acts upon the switch1 closes the local battery circuit and leaves it closed1 while the bell goes on ringing until the battery is exhausted or the switch is opened by hand4 ,eye1 ,electro-magnetic4 ,an apparatus used in exploring a field of electro-magnetic radiations4 ,it is a piece of copper wire #b millimeters 74#jh inch7 in diameter1 bent into an almost complete circle #gj millimeters 74#bh inch7 in diameter1 with terminals separated by an air gap4 ,this is moved about in the region under examination1 and by the production of a spark indicates the locality of the loops or venters in systems of stationary waves4 ,f4 ,abbreviation for ,fahrenheit1 as #aj ,f41 meaning #aj ,fahrenheit4 7,see ,fahrenheit ,scale47 ,fahrenheit ,scale4 ,a thermometer scale in use in the ,united ,states and ,england4 ,on this scale the temperature of melting ice is #cb2 that of condensing steam is #bab2 the degrees are all of equal length4 ,its use is indicated by the letter ,f41 as #ahj ,f4 ,to convert its readings into centigrade1 subtract #cb and multiply by #e_/i4 7b7 ,to convert centigrade into ,f4 multiply by #i_/e and add #cb4 ,thus #ahj ,f4 77#ahj-cb7 99 #e_/i7 ,c4 #hb4b ,c4 ,again #ahj ,c4 7#ahj 99 #i_/e7 #cb #cbd ,f4 ,transcribers note3 #ahj ,c4 7#ahj 99 #i_/e7 #cb #cef ,f4 ,the additions and subtractions must be algebraic in all cases4 ,thus when the degrees are minus or below zero the rules for conversion might be put thus3 ,to convert degrees ,f4 below zero into centigrade to the number of degrees ,f4 add #cb1 multiply by #e_/i and place a minus sign 7-7 before it4 7b7 ,to convert degrees centigrade below zero into ,fahrenheit1 multiply the number of degrees by #i_/e1 subtract from #cb if smaller2 if greater than #cb subtract #cb therefrom1 and prefix a minus sign1 thus3 -#aj ,c4 #cb - 7#aj 99 #i_/e7 #ad4 ,again1 -#cj;,c4 7#cj 99 #i_/e7 - #cb #bb -#bb ,f4 #bdi ,,standard ,,electrical ,,dictionary4 ,farad4 ,the practical unit of electric capacity2 the capacity of a conductor which can retain one coulomb of electricity at a potential of one volt4 ,the quantity of electricity charged upon a conducting surface raises its potential2 therefore a conductor of one farad capacity can hold two coulombs at two volts potential1 and three coulombs at three volts1 and so on4 ,the electric capacity of a conductor1 therefore1 is relative compared to others as regards its charge1 for the latter may be as great as compatible with absence of sparking and disruptive discharge4 ,in other words1 a one farad or two farad conductor may hold a great many coulombs4 ,charging a conductor with electricity is comparable to pumping air into a receiver4 ,such a vessel may hold one cubic foot of air at atmospheric pressure and two at two atmospheres1 and yet be of one cubic foot capacity however much air is pumped into it4 ,the farad is equal to one fundamental electrostatic unit of capacity multiplied by #i;,e#aa and to one electro-magnetic unit multiplied by #a;,e-#i4 ,the farad although one of the practical units is far too large1 so the micro-farad is used in its place4 ,the capacity of a sphere the size of the earth is only 4#jjjfcf of a farad4 ,transcriber's note3 ,contemporary calculations give about 4#jjjgbj farad4 ,faraday1 ,effect4 ,the effect of rotation of its plane produced upon a polarized beam of light by passage through a magnetic field4 7,see ,magnetic ,rotary ,polarization47 ,faraday's ,cube4 ,to determine the surface action of a charge1 ,faraday constructed a room1 twelve feet cube1 insulated1 and lined with tinfoil4 ,this room he charged to a high potential1 but within it he could detect no excitement whatever4 ,the reason was because the electricity induced in the bodies within the room was exactly equal to the charge of the room-surface1 and was bound exactly by it4 ,the room is termed ,faraday's cube4 ,faraday's ,dark ,space4 ,a non-luminous space between the negative and positive glows1 produced in an incompletely exhausted tube through which a static discharge1 as from an induction coil1 is produced4 ,it is perceptible in a rarefaction of #f millimeters 74#bd inch7 and upwards4 ,if the exhaustion is very high a dark space appears between the negative electrode and its discharge4 ,this is known as ,crookes' dark space4 ,faraday's ,disc4 ,a disc of any metal1 mounted so as to be susceptible of rotation in a magnetic field of force1 with its axis parallel to the general direction of the lines of force4 ,a spring bears against its periphery and another spring against its axle4 ,when rotated1 if the springs are connected by a conductor1 a current is established through the circuit including the disc and conductor4 ,the radius of the disc between the spring contacts represents a conductor cutting lines of force and generating a potential difference1 producing a current4 ,if a current is sent through the motionless wheel from centre to periphery it rotates1 illustrating the doctrine of reversibility4 ,as a motor it is called ,barlow's or ,sturgeon's ,wheel4 ,if the disc without connections is rapidly rotated it produces ,foucault currents1 q4 v41 within its mass1 which resist its rotation and heat the disc4 #bej ,,standard ,,electrical ,,dictionary4 ,fig4 #afh4 ,,faraday',s ,,net4 ,faraday's ,net4 ,an apparatus for showing that the electric charge resides on the surface4 ,it consists of a net1 conical in shape and rather deep1 to whose apex two threads1 one on each side1 are attached4 ,its mouth is fastened to a vertical ring and the whole is mounted on an insulating support4 ,it is pulled out to its full extent and is electrified4 ,no charge can be detected inside it4 ,by pulling one of the threads it is turned with the other side out4 ,now all the charge is found on the outside just as before1 except that it is of course on the former inside surface of the bag4 ,the interior shows no charge4 ,faraday's ,transformer4 ,the first transformer4 ,it was made by ,michael ,faraday4 ,it was a ring of soft iron #g_/h inch thick1 and #f inches in external diameter4 ,it was wound with bare wire1 calico being used to prevent contact of the wire with the ring and of the layers of wire with each other1 while twine was wound between the convolutions to prevent the wires from touching4 ,seventy-two feet of copper wire1 #a_/bj inch diameter1 were wound in three superimposed coils1 covering about one-half of the ring4 ,on the other half sixty feet of copper wire were wound in two superimposed coils4 ,faraday connected his coils in different ways and used a galvanometer to measure the current produced by making and breaking one of the circuits used as a primary4 ,the coil is of historic interest4 ,faraday's ,voltameter4 ,a voltameter1 in which the coulombs of current are measured by the volume of the gas evolved from acidulated water4 7,see ,voltameter1 ,gas47 ,faradic4 adj4 ,referring to induced currents1 produced from induction coils4 ,as ,faraday was the original investigator of the phenomena of electro-magnetic induction1 the secondary or induced electro-magnetic currents and their phenomena and apparatus are often qualified by the adjective ,faradic1 especially in electro-therapeutics4 ,a series of alternating electrostatic discharges1 as from an influence machine 7,holtz71 are sometimes called ,franklinic currents4 ,they are virtually ,faradic1 except as regards their production4 #bea ,,standard ,,electrical ,,dictionary4 ,faradic ,brush4 ,a brush for application of electricity to the person4 ,it is connected as one of the electrodes of an induction coil or magneto generator4 ,for bristles wire of nickel plated copper is generally employed4 ,faradization4 ,in medical electricity the analogue of galvanization2 the effects due to secondary or induced currents2 galvanization referring to currents from a galvanic battery2 also the process of application of such currents4 ,faults4 ,sources of loss of current or of increased resistance or other troubles in electric circuits4 ,feeder4 ,a lead in an electric central station distribution system1 which lead runs from the station to some point in the district to supply current4 ,it is not used for any side connections1 but runs direct to the point where current is required1 thus feeding the district directly4 ,in the two wire system a feeder may be positive or negative2 in the three wire system there is also a neutral feeder4 ,often the term feeder includes the group of two or of three parallel lines4 ,feeder ,equalizer4 ,an adjustable resistance connected in circuit with a feeder at the central station4 ,the object of the feeder being to maintain a definite potential difference at its termination1 the resistance has to be varied according to the current it is called on to carry4 ,feeder1 ,main or ,standard4 ,the main feeder of a district4 ,the standard regulation of pressure 7potential difference between leads7 in the district is often determined by the pressure at the end of the feeder4 ,feeder1 ,negative4 ,the lead or wire in a set of feeders1 which is connected to the negative terminal of the generator4 ,feeder1 ,neutral4 ,in the three wire system the neutral wire in a set of feeders4 ,it is often made of less diameter than the positive and negative leads4 ,feeder1 ,positive4 ,the lead or wire in a set of feeders1 which wire is connected to the positive terminal of the generator4 ,ferranti ,effect4 ,an effect as yet not definitely explained1 observed in the mains of the ,deptford1 ,eng41 alternating current plant4 ,it is observed that the potential difference between the members of a pair of mains rises or increases with the distance the place of trial is from the station4 ,transcriber's note3 ,this effect is due to the voltage drop across the line inductance 7due to charging current7 being in phase with the sending end voltages4 ,both capacitance and inductance are responsible for producing this phenomenon4 ,the effect is more pronounced in underground cables and with very light loads4 #beb ,,standard ,,electrical ,,dictionary4 ,ferro-magnetic4 adj4 ,paramagnetic2 possessing the magnetic polarity of iron4 ,fibre and ,spring ,suspension4 ,a suspension of the galvanometer needle used in marine galvanometers4 ,the needle is supported at its centre of gravity by a vertically stretched fibre attached at both its ends1 but with a spring intercalated between the needle and one section of the fibre4 ,fibre ,suspension4 ,suspension1 as of a galvanometer needle1 by a vertical or hanging fibre of silk or cocoon fibre1 or a quartz fibre4 7,see ,quartz47 ,this suspension1 while the most delicate and reliable known1 is very subject to disturbance and exacts accurate levelling of the instrument4 ,fibre suspension is always characterized by a restitutive force4 ,pivot suspension1 q4 v41 on the other hand1 has no such force4 ,field1 ,air4 ,a field the lines of force of which pass through air2 the position of a field comprised within a volume of air4 ,field1 ,alternating4 ,polarity or direction being attributed to lines of force1 if such polarity is rapidly reversed1 an alternating field results4 ,such field may be of any kind1 electro-magnetic or electrostatic4 ,in one instance the latter is of interest4 ,it is supposed to be produced by high frequency discharges of the secondary of an induction coil1 existing in the vicinity of the discharging terminals4 ,field ,density4 ,field density or density of field is expressed in lines of force per unit area of cross-section perpendicular to the lines of force4 ,field1 ,distortion of4 ,the lines of force reaching from pole to pole of an excited field magnet of a dynamo are normally symmetrical with respect to some axis and often with respect to several4 ,they go across from pole to pole1 sometimes bent out of their course by the armature core1 but still symmetrical4 ,the presence of a mass of iron in the space between the pole pieces concentrates the lines of force1 but does not destroy the symmetry of the field4 ,when the armature of the dynamo is rotated the field becomes distorted1 and the lines of force are bent out of their natural shape4 ,the new directions of the lines of force are a resultant of the lines of force of the armature proper and of the field magnet4 ,for when the dynamo is started the armature itself becomes a magnet1 and plays its part in forming the field4 ,owing to the lead of the brushes the polarity of the armature is not symmetrical with that of the field magnets4 ,hence the compound field shows distortion4 ,in the cut is shown diagrammatically the distortion of field in a dynamo with a ring armature4 ,the arrow denotes the direction of rotation1 and n n 99 99 99 and s s 99 99 99 indicate points of north and south polarity respectively4 #bec ,,standard ,,electrical ,,dictionary4 ,the distorted lines must be regarded as resultants of the two induced polarities of the armature1 one polarity due to the induction of the field1 the other to the induction from its own windings4 ,the positions of the brushes have much to do with determining the amount and degree of distortion4 ,in the case of the ring armature it will be seen that some of the lines of force within the armature persist in their polarity and direction1 almost as induced by the armature windings alone1 and leak across without contributing their quota to the field4 ,two such lines are shown in dotted lines4 ,in motors there is a similar but a reversed distortion4 ,fig4 #afi4 ,,distortion ,,of ,,field ,,in ,a ,,ring ,,armature ,,of ,,an ,,active ,,dynamo4 ,fig4 #agj4 ,,distortion ,,of ,,field ,,in ,a ,,ring ,,armature ,,of ,,an ,,active ,,motor4 #bed ,,standard ,,electrical ,,dictionary4 ,field1 ,drag of4 ,when a conductor is moved through a field so that a current is generated in it1 the field due to that current blends with the other field and with its lines of force1 distorting the field1 thereby producing a drag upon its own motion1 because lines of force always tend to straighten themselves1 and the straightening would represent cessation of motion in the conductor4 ,this tendency to straightening therefore resists the motion of the conductor and acts a drag upon it4 ,field of ,force4 ,the space in the neighborhood of an attracting or repelling mass or system4 ,of electric fields of force there are two kinds1 the ,electrostatic and the ,magnetic ,fields of ,force1 both of which may be referred to4 ,a field of force may be laid out as a collection of elements termed ,lines of ,force1 and this nomenclature is universally adopted in electricity4 ,the system of lines may be so constructed that 7a7 the work done in passing from one equipotential surface to the next is always the same2 or 7b7 the lines of force are so laid out and distributed that at a place in which unit force is exercised there is a single line of force passing through the corresponding equipotential surface in each unit of area of that surface4 ,the latter is the universal method in describing electric fields4 ,it secures the following advantages3--,first3 ,the potential at any point in the field of space surrounding the attracting or repelling mass or masses is found by determining on which imaginary equipotential surface that point lies4 ,second3 ,if unit length of a line of force cross n equipotential surfaces1 the mean force along that line along the course of that part of it is equal to n units2 for the difference of potential of the two ends of that part of the line of force n2 it is also equal to ,f s 7,f force71 because it represents numerically a certain amount of work2 but s ,i1 whence n ,f4 ,third3 ,the force at any part of the field corresponds to the extent to which the lines of force are crowded together2 and thence it may be determined by the number of lines of force which pass through a unit of area of the corresponding equipotential surface1 that area being so chosen as to comprise the point in question4 7,daniell47 ,field of ,force1 ,electrostatic4 ,the field established by the attracting1 repelling and stressing influence of an electrostatically charged body4 ,it is often termed an ,electrostatic ,field4 7,see ,field of ,force47 #bee ,,standard ,,electrical ,,dictionary4 ,field of ,force of a ,current4 ,a current establishes a field of force around itself1 whose lines of force form circles with their centres on the axis of the current4 ,the cut1 ,fig4 #agb1 shows the relation of lines of force to current4 ,fig4 #aga4 ,,experiment ,,showing ,,lines ,,of ,,force ,,surrounding ,,an ,,active ,,conductor4 ,fig4 #agb4 ,,diagram ,,of ,,field ,,of ,,force ,,surrounding ,,an ,,active ,,conductor4 ,fig4 #agc4 ,,link ,,of ,,force ,,induced ,,by ,a ,,current ,,showing ,,the ,,magnetic ,,whirls4 ,the existence of the field is easily shown by passing a conductor vertically through a horizontal card4 ,on causing a current to go through the wire the field is formed1 and iron filings dropped upon the card1 tend1 when the latter is gently tapped1 to take the form of circles4 ,the experiment gives a version of the well-known magnetic figures1 q4 v4 ,see ,fig4 #aga4 ,the cut shows by the arrows the relation of directions of current to the direction of the lines of force1 both being assumptions1 and merely indicating certain fixed relations1 corresponding exactly to the relations expressed by the directions of electro-magnetic or magnetic lines of force #bef ,,standard ,,electrical ,,dictionary4 ,field1 ,pulsatory4 ,a field produced by pulsatory currents4 ,by induction such field can produce an alternating current4 ,field1 ,rotating4 ,in a dynamo the field magnets are sometimes rotated instead of the armature1 the latter being stationary4 ,in ,mordey's alternator the armature1 nearly cylindrical1 surrounds the field1 and the latter rotates within it1 the arrangement being nearly the exact reverse of the ordinary one4 ,this produces a rotating field4 ,field1 ,rotatory4 ,a magnetic field whose virtual poles keep rotating around its centre of figure4 ,if two alternating currents differing one quarter period in phase are carried around four magnetizing coils placed and connected in sets of two on the same diameter and at right angles to each other1 the polarity of the system will be a resultant of the combination of their polarity1 and the resultant poles will travel round and round in a circle4 ,in such a field1 owing to eddy currents1 masses of metal1 journaled like an armature1 will rotate1 with the speed of rotation of the field4 ,field1 ,stray4 ,the portion of a field of force outside of the regular circuit2 especially applied to the magnetic field of force of dynamos expressing the portion which contributes nothing to the current generation4 ,synonym--,waste ,field4 ,field1 ,uniform4 ,a field of force of uniform density4 7,see ,field ,density47 ,figure of ,merit4 ,in the case of a galvanometer1 a coefficient expressing its delicacy4 ,it is the reciprocal of the current required to deflect the needle through one degree4 ,by using the reciprocal the smaller the current required the larger is the figure of merit4 ,the same term may be applied to other instruments4 ,it is often defined as the resistance of a circuit through which one ,daniell's element will produce a deflection of one degree on the scale of the instrument4 ,the circuit includes a ,daniell's cell of resistance r1 a rheostat ,r1 galvanometer ,g and shunt ,s4 ,assume that with the shunt in parallel a deflection of a divisions is obtained4 ,the resistance of the shunted galvanometer is 7,,gs_/,g,s 2 the multiplying power m of the shunt is ,s,g_/,s2 the formula or figure of merit is m d 7r,r ,g ,s_/,g,s74 ,the figure of merit is larger as the instrument is more sensitive4 ,synonym--,formula of ,merit4 #beg ,,standard ,,electrical ,,dictionary4 ,filament4 ,a thin long piece of a solid substance4 ,in general it is so thin as to act almost like a thread1 to be capable of standing considerable flexure4 ,the distinction between filament and rod has been of much importance in some patent cases concerning incandescent lamps4 ,as used by electricians the term generally applies to the carbon filament of incandescent lamps4 ,this as now made has not necessarily any fibres1 but is entitled to the name of filament1 partly by convention1 partly by its relative thinness and want of stiffness4 7,see ,incandescent ,lamps--,magnetic ,filament47 ,fire ,alarm1 ,electric1 ,automatic4 ,a system of telegraph circuits1 at intervals supplied with thermostats or other apparatus affected by a change of temperature1 which on being heated closes the circuit and causes a bell to ring4 7,see ,thermostat47 ,fire ,alarm ,telegraph ,system4 ,a system of telegraphic lines for communicating the approximate location of a fire to a central station and thence to the separate fire-engine houses in a city or district4 ,it includes alarm boxes1 distributed at frequent intervals1 locked1 with the place where the key is kept designated1 or in some systems left unlocked4 ,on opening the door of the box and pulling the handle or otherwise operating the alarm1 a designated signal is sent to the central station4 ,from this it is telegraphed by apparatus worked by the central station operator to the engine houses4 ,the engines respond according to the discipline of the service4 ,fire ,cleansing4 ,freeing the surface of an article to be plated from grease by heating4 ,fire ,extinguisher1 ,electric1 ,automatic4 ,a modification of the electric fire alarm 7see ,fire ,alarm1 ,electric1 ,automatic71 in which the thermostats completing the circuits turn on water which1 escaping through the building1 is supposed to reach and extinguish a fire4 ,flashing in a ,dynamo or ,magneto-electric ,generator4 ,bad adjustment of the brushes at the commutator1 or other fault of construction causes the production of voltaic arcs at the commutator of a generator1 to which the term flashing is applied4 ,flashing of ,incandescent ,lamp ,carbons4 ,a process of treatment for the filaments of incandescent lamps4 ,the chamber before sealing up is filled with a hydro-carbon vapor or gas1 such as the vapor of a very light naphtha 7rhigolene74 ,a current is then passed through the filament heating it to redness4 ,the more attenuated parts or those of highest resistance are heated the highest1 and decompose most rapidly the hydro-carbon vapor1 graphitic carbon being deposited upon these parts1 while hydrogen is set free4 ,this goes on until the filament is of uniform resistance throughout4 ,it gives also a way of making the resistance of the filament equal to any desired number of ohms1 provided it is originally of high enough resistance4 ,the process increases the conductivity of the filament4 ,after flashing the chambers are pumped out and sealed up4 #beh ,,standard ,,electrical ,,dictionary4 ,flashing ,over4 ,a phenomenon observed in high potential dynamos4 ,on a sudden alteration of the resistance of the circuit a long blue spark will be drawn out around the surface of the commutator from brush to brush4 ,the spark is somewhat of the nature of an arc1 and may seriously injure commutators whose sections are only separated by mica1 or other thin insulation4 ,in the case of commutators whose sections are separated by air spaces it is not so injurious4 ,flats4 ,in a commutator of a dynamo1 the burning or wearing away of a commutator segment to a lower level than the rest4 ,sometimes two adjacent bars will be thus affected1 causing a flat place on the commutator4 ,it is not always easy to account for the formation of flats4 ,they may have their origin in periodic vibrations due to bad mounting1 or to sparking at the particular point4 ,floor ,push4 ,a press or push button constructed to be set into the floor to be operated by pressing with the foot4 ,it is used to ring an alarm bell1 sound a buzzer or for similar service4 ,fluid1 ,depolarizing4 ,a fluid used in voltaic batteries to dispose of the hydrogen1 which goes to the negative plate4 ,this it does by oxidizing it4 ,chromic acid1 nitric acid1 and chloric acids are among the constituents of liquid depolarizers4 7,see ,electropoion ,fluid47 ,fluid1 ,electric4 ,the electric current and charge have sometimes been attributed to a fluid4 ,the theory1 which never was much more than hypothetical1 survives to some extent in the single and double fluid theory4 7,see ,single ,fluid ,theory-,double ,fluid ,theory47 ,fluorescence4 ,the property of converting ether waves of one length1 sometimes of invisible length1 into waves of another length 7visible74 ,a,esculin1 quinine salts1 uranium glass and other substances exhibit this phenomenon4 ,the phenomenon is utilized in the production of ,geissler tubes4 ,flush ,boxes4 ,a heavy iron box covered with a heavy hand plate and laid flush 7whence the name71 or even with the surface of a roadway4 ,into it conductors of an underground system lead1 and it is used to make connections therewith and for examining the leakage of the conductors and for similar purposes4 ,it is a man-hole 7q4 v47 in miniature4 ,fluviograph4 ,an electric registering tide gauge or water level gauge4 #bei ,,standard ,,electrical ,,dictionary4 ,fly or ,flyer1 ,electric4 ,a little wheel1 ordinarily poised on a point1 like a compass needle4 ,it carries several tangentially directed points1 all pointing in the same sense4 ,when connected with a source of electricity of high potential it revolves by reaction4 ,the tension of its charge is highest at the points1 the air there is highly electrified and repelled1 the reaction pushing the wheel around like a ,barker's mill or ,hero's steam engine4 ,sometimes the flyer is mounted with its axis horizontal and across the rails on a railroad along which it travels4 ,synonym--,reaction ,wheel4 ,foci ,magnetic4 ,the two points on the earth's surface where the magnetic intensity is greatest4 ,they nearly coincide in position with the magnetic poles4 ,fog1 ,electric4 ,fogs occurring when the atmosphere is at unusually high potential and accompanied by frequent change of such polarity4 ,following ,horns4 ,in dynamo-electric machines the projecting ends of the pole pieces towards which the outer uncovered perimeter of the armature turns in its regular operations4 ,the leading horns are those away from which the armature rotates4 ,in considering rotation the exposed portion of the superficies of the armature is considered4 ,the definition would have to be reversed if the part facing the pole pieces were considered4 ,synonym--,trailing ,horns4 ,foot-candle4 ,a unit of illuminating power2 the light given by one standard candle at a distance of one foot4 ,the ordinary units of illuminating power are entirely relative2 this is definite4 ,it is due to ,carl ,herring4 ,foot-pound4 ,a practical unit of work or energy4 ,the quantity of work required to raise a pound one foot1 or one hundred pounds one-hundredth of a foot1 and so on2 or the potential energy represented by a weight at an elevation under these conditions4 ,foot-step4 ,in a dynamo with armature at the lower end of its field magnets1 the plate generally of zinc1 interposed between it and the iron base plate to prevent the leakage of lines of force outside of the circuit4 ,any diamagnetic material which is mechanically suitable may be used4 ,force4 ,force may be variously defined4 7a7 ,any cause of change of the condition of matter with respect to motion or rest4 7b7 ,a measurable action upon a body under which the state of rest of that body1 or its state of uniform motion in a straight line1 suffers change4 7c7 ,it may be defined by its measurement as the rate of change of momentum1 or 7d7 as the rate at which work is done per unit of space traversed4 ,force is measured by the acceleration or change of motion it can impart to a body of unit mass in a unit of time1 or1 calling force1 ,f1 mass1 m acceleration per second a we have ,f m a4 ,the dimensions of force are mass 7,m7 99 acceleration 7,l_/7,t#b77 7,m99,l7_/7,t#b74 #bfj ,,standard ,,electrical ,,dictionary4 ,force de ,cheval4 ,horse power 7,french74 ,it is the ,french or metric horse power4 ,it is equal to3 #edb4dif ,foot lbs4 per second4 4#ihfd ,english ,horse ,power4 #ge4j ,kilogram-meters per second4 ,force1 ,electro-magnetic4 ,the mechanical force of attraction or repulsion acting on the electro-magnetic unit of quantity4 ,its intensity varies with the square of the distance4 ,it may also be defined as electric force in the electro-magnetic system4 ,its dimensions are equal to mechanical force 77,m99,l7_/7,t#b77 divided by quantity 77,m4#e7997,l4#e77 77,m4#e7997,l4#e77_/7,t#b74 ,force1 ,electrostatic4 ,the force by which electric matter or electrified surfaces attract or repel each other4 ,it is also termed electric force 7not good7 and electro-motive intensity4 ,it is the mechanical force acting upon a unit quantity of electricity4 ,its intensity varies with the square of the distance4 ,its dimensions are therefore equal to 7quantity 99 unity _/ 7square of distance7 ,q4 99 #a _/ 7,l#b7 77,m4#e7 99 7,l#a4e7 7_/ ,t99#a _/ 7,l#b7 77,m4#e7 99 7,l4#e77 _/ ,t ,these dimensions are also those of potential difference4 ,transcriber's ,note3 ,the image of the preceding paragraph is included for clarity4 ,the objection to the term electric force is that it may be applied also to electro-magnetic force1 and hence be a source of confusion4 ,forces1 ,parallelogram of4 ,the usual method of composing forces or resolving a force4 ,the sides of a parallelogram of forces represent component forces and the diagonal represents the resultant4 ,see ,component--,resultant--,forces1 ,composition of--,forces1 ,resolution of4 ,forces1 ,composition of4 ,when several forces act in a different direction upon a point they may be drawn or graphically represented as arrows or lines emanating from the point in the proper direction and of lengths proportional to the force they exercise4 ,any two can be treated as contiguous sides of a parallelogram and the parallelogram can be completed4 ,then its diagonal1 called the resultant1 will represent the combined action of the two forces1 both as regards direction and intensity4 ,this is the composition of two forces4 ,if more than two forces act upon the given point the resultant can be composed with any of the others and a new force developed4 ,the new resultant can be combined with another force1 and the process kept up1 eliminating the components one by one until a final resultant of all is obtained4 ,this will give the exact direction and intensity of the forces1 however many or varied4 #bfa ,,standard ,,electrical ,,dictionary4 ,forces1 ,resolution of4 ,the developing from a single force treated as a resultant1 two other forces in any desired direction4 ,the reverse of composition of forces4 7,see ,forces1 ,composition of--,forces1 ,parallelogram of--,components--,resultant47 ,force1 ,tubes of4 ,aggregations of lines of force1 either electrostatic or magnetic4 ,they generally have a truncated1 conical or pyramidal shape and are not hollow4 ,every cross-section contains the same number of lines4 ,the name it will seem is not very expressive4 ,force1 ,unit of4 ,the fundamental or ,c4 ,g4 ,s4 unit or force is the dyne1 q4 v4 ,the ,british unit of force is the poundal 7the force which will produce an acceleration of one foot per second in a mass of one pound74 ,it is equal to about #aj_/cbb pound4 ,a force cannot be expressed accurately in weight units1 because weight varies with the latitude4 ,forming4 ,the process of producing secondary battery plates from lead plates by alternately passing a charging current through the cell and then allowing it to discharge itself and repeating the operation4 7,see ,battery1 ,secondary1 ,plant's47 ,foundation ,ring4 ,in a dynamo armature the ring-shaped core on which ,gramme ring armatures and other ring armatures are wound4 ,fourth ,state of ,matter4 ,gas so rarefied that its molecules do not collide1 or rarely do so2 radiant matter1 q4 v4 ,transcriber's note3 ,this term now refers to plasma1 an ionized gas1 which contains free electrons4 ,the ions and electrons move somewhat independently making plasma electrically conductive4 ,it responds strongly to electromagnetic fields4 ,frame4 ,in a dynamo the bed-piece is sometimes called the frame4 ,franklin's ,experiment4 ,franklin proved the identity of lightning and electricity by flying a kite in a thunder storm4 ,the kite was of silk so as to endure the wetting4 ,when the string became wet sparks could be taken from a key attached to its end4 ,the main string was of hemp2 at the lower end was a length of silk to insulate it4 ,the key was attached near the end of and to the hemp string4 ,franklin's ,plate4 ,a simple form of condenser4 ,it consists of a plate of glass coated on each side with tinfoil with a margin of about an inch of clear glass4 ,one coating may be grounded as indicated in the cut1 and the plate charged like a ,leyden jar4 ,or one side may be connected with one terminal1 and the other with the other terminal of an influence machine and the pane will be thus charged4 ,synonym--,fulminating ,pane4 #bfb ,,standard ,,electrical ,,dictionary4 ,fig4 #agd4 ,,franklin',s ,,plate4 ,franklin's ,theory4 ,the single fluid theory1 q4 v41 of electricity4 ,frequency4 ,the number of double reversals or complete alternations per second in an alternating current4 ,synonym--,periodicity4 ,frictional ,electricity4 ,electricity produced by friction of dissimilar substances4 7,see ,electrostatic ,series47 ,the contact theory holds that friction plays only a secondary rle in this process2 that it increases the thoroughness of contact1 and tends to dry the rubbing surfaces1 but that the charges induced are due to contact of dissimilar substances1 not to friction of one against the other4 ,frictional ,heating4 ,the heating of a conductor by the passage of a current2 the ,joule effect1 q4 v4 ,fringe4 ,the outlying edge of a magnetic field4 ,frog1 ,galvani's ,experiment ,with4 ,a classic experiment in electricity1 leading to the discovery of current or dynamic electricity4 ,if a pair of legs of a recently killed frog are prepared with the lumbar nerves exposed near the base of the spinal column1 and if a metallic conductor1 one half-length zinc and the other half-length copper1 is held1 one end between the lumbar nerves and the spine1 and the other end against one of the muscles of the thigh or lower legs1 the moment contact occurs and the circuit is completed through the animal substance the muscles contract and the leg is violently drawn upwards4 ,galvani1 in #aghf1 first performed1 by accident1 this famous experiment1 it is said1 with a scalpel with which he was dissecting the animal4 ,he gave his attention to the nerves and muscles4 ,volta1 more happily1 gave his attention to the metals and invented the voltaic battery1 described by him in a letter to ,sir ,joseph ,banks1 dated #ahjj4 ,frog1 ,rheoscopic4 ,if the nerve or living muscle of a frog is suddenly dropped upon another living muscle so as to come in contact with its longitudinal and transverse sections1 the first muscle will contract on account of the stimulation of its nerve due to the passage of a current derived from the second muscle 7,ganot74 ,the experiment goes under the above title4 #bfc ,,standard ,,electrical ,,dictionary4 ,frying4 ,a term applied to a noise sometimes produced in a voltaic arc due to too close approach of the carbons to each other4 ,it has been suggested that it may be due to volatilization of the carbon4 7,elihu ,thomson47 ,fulgurite4 ,an irregular and tubular mass of vitrified quartz1 believed to be formed by melting under the lightning stroke4 ,fig4 #age4 ,,crucible1 ,,electric4 ,furnace1 ,electric4 ,a furnace in which the heat is produced by the electric current4 ,it has hitherto been practically used only in the extraction of aluminum and silicium from their ores4 ,the general principle involves the formation of an arc between carbon electrodes4 ,the substances to be treated are exposed to the heat thus produced4 ,sometimes the substances in the arc form imperfect conductors1 and incandescence takes a part in the action4 ,sometimes the substances are merely dropped through the arc4 ,transcriber's note3 ,silicium is silicon4 ,fuse ,board4 ,a tablet on which a number of safety fuses are mounted4 ,slate is excellent material for the tablet1 as it is incombustible1 and is easily drilled and worked4 ,fuse ,box4 ,a box containing a safety fuse4 ,porcelain is an excellent material for its base4 ,no combustible material should enter into its composition4 ,fuse1 ,cockburn4 ,a safety fuse or cut off which consists of a wire of pure tin running from terminal to terminal1 to whose centre a leaden ball is secured by being cast into position4 ,the connection with the terminals is made by rings at the ends of the wire through which the terminal screws are passed and screwed home4 ,when the tin softens under too heavy a current the weight of the shot pulls it apart4 ,fig4 #agf ,,cockburn ,,safety ,,fuse4 #bfd ,,standard ,,electrical ,,dictionary4 ,fig4 #agg4 ,,electric ,,fuse4 ,fuse1 ,electric4 ,a fuse for igniting an explosive by electricity4 ,there are two kinds4 ,in one a thin wire unites the ends of the two conducting wires as they enter the case of the fuse4 ,the larger wires are secured to the case1 so that no strain comes on the fine wire4 ,on passing a current of sufficient strength the small wire is heated4 ,in use the fuse is bedded in powder1 which again may be surrounded by fulminating powder1 all contained in a copper or other metallic case4 ,such a detonator is used for exploding guncotton and other high explosives4 ,the other kind of fuse is similar1 but has no thin connecting wire4 ,the ends of the conductors are brought nearer together without touching4 ,in use a static discharge is produced across from end to end of the conductors1 igniting a proper explosive placed there as in the other case4 ,the first kind of fuse is generally operated by a battery or small mechanical generator--the latter by a spark coil1 frictional or influence machine or by a ,leyden jar4 ,galvanic4 adj4 ,voltaic2 relating to current electricity or the electrolytic and electro-chemical relations of metals4 7,for titles in general under this head see ,voltaic--or the main title47 ,galvanic ,element4 ,a galvanic couple with exciting fluid and adjuncts2 a galvanic cell4 ,the word element is sometimes applied to the electrodes of a cell1 as the carbon element or zinc element4 #bfe ,,standard ,,electrical ,,dictionary4 ,galvanic ,polarization4 ,the polarization of a voltaic couple4 7,see ,polarization47 ,galvanism4 ,the science of voltaic or current electricity4 ,galvanization4 7a7 ,electroplating or depositing a metal over the surface of another by electrolysis4 7b7 ,in medical electricity the effects produced on any part of the system by the current of voltaic battery4 ,various descriptive qualifications are prefixed1 such as general galvanization1 indicating its application as applied to the whole body1 local for the reverse case1 and so on4 ,galvanization1 ,labile4 ,application of the galvanic current in electro-therapeutics where one sponge electrode is employed which is rubbed or moved over the body1 the other being in constant contact with the body4 ,galvanized ,iron4 ,iron coated with zinc by cleaning and immersion in melted zinc4 ,the iron is prevented from rusting by galvanic action4 ,it forms the negative element in a couple of which the zinc is the positive element4 ,from this electric protective action the name is derived4 ,galvano-cautery1 ,chemical4 ,electro-therapeutic treatment with sharp electrodes1 one of which is inserted in the tissue and a current passed by completing the circuit through the tissue so as to electrolyze or decompose the fluids of the tissue4 ,it is applied in the removal of hair or extirpation of the follicle4 ,the process is not one of heating1 and is improperly named cautery4 ,galvano-faradization4 ,in medical electricity the application of the voltaic and induced or secondary current simultaneously to any part of the system4 ,galvanometer4 ,an instrument for measuring current strength and sometimes for measuring inferentially potential difference1 depending on the action of a magnetic field established by the current1 such action being exerted on a magnetic needle or its equivalent4 ,a current passing through a conductor establishes circular lines of force4 ,a magnetic needle placed in their field is acted on and tends to place itself parallel with the lines1 in accordance with the principles of current induction4 7,see ,induction1 ,electro-magnetic47 ,a common compass held near a conductor through which a current is passing tends to place itself at right angles to such conductor4 ,for a maximum effect the conductor or the part nearest the needle should lie in the magnetic meridian4 ,if at right angles thereto its action will only strengthen the directive force of the earth's induction or magnetic field1 as the needle naturally points north and south4 ,such combination is virtually a galvanometer4 #bff ,,standard ,,electrical ,,dictionary4 ,a typical galvanometer comprises a flat coil of wire placed horizontally within which a magnetic needle is delicately poised1 so as to be free to rotate with the least possible friction4 ,the needle may be supported on a sharp point like a compass needle1 or may be suspended by a long fine filament4 ,it should be covered by a glass plate and box1 or by a glass shade4 ,finally a graduated disc may be arranged to show the amount of deflection of the needle4 ,in use the apparatus is turned about until the needle1 as acted on by the earth's magnetic field1 lies parallel to the direction of the coils of wire4 ,on passing a current through the coil the needle is deflected1 more or less1 according to its strength4 ,by using exceedingly fine wire1 long enough to give high resistance1 the instrument can be used for very high potentials1 or is in condition for use in determining voltage4 ,by using a coil of large wire and low resistance it can be employed in determining amperage4 ,in either case the deflection is produced by the current4 ,the needle is often placed above or below the coil so as only to receive a portion of its effect1 enough for all practical purposes in the commoner class of instruments4 ,the galvanometer was invented by ,schweigger a short time after ,oersted's discovery1 q4 v4 ,galvanometer1 ,absolute4 ,a galvanometer giving absolute readings2 properly one whose law of calibration can be deduced from its construction4 ,thus the diameter of the coil1 and the constants and position of a magnetic needle suspended in its field being known1 the current intensity required to deflect the needle a given number of degrees could be calculated4 ,galvanometer1 ,aperiodic4 ,a galvanometer whose needle is damped 7see ,damping7 as1 for instance1 by the proximity of a plate of metal1 by an air vane or otherwise1 so that it reaches its reading with hardly any oscillation4 ,a very light needle and a strong magnetic field also conduce to vibrations of short period dying out very quickly4 ,such galvanometers are termed dead-beat4 ,no instrument is absolutely dead-beat1 only relatively so4 #bfg ,,standard ,,electrical ,,dictionary4 ,fig4 #agh4 ,,astatic ,,galvanometer4 ,galvanometer1 ,astatic4 ,a galvanometer with a pair of magnetic needles connected astatically1 or parallel with their poles in opposition4 7,see ,astatic ,needle47 ,each needle has its own coil1 the coils being wound in opposite directions so as to unite in producing deflections in the same sense4 ,as there should be some directive tendency this is obtained by one of the magnets being slightly stronger than the other or by the proximity of a fixed and adjustable controlling magnet1 placed nearer one needle than the other4 ,for small deflections the currents producing them are proportional to their extent4 ,galvanometer1 ,ballistic4 ,a galvanometer whose deflected element has considerable moment of inertia2 the exact opposite of an aperiodic or dead beat galvanometer4 7,see ,galvanometer1 ,aperiodic47 ,all damping by air vanes or otherwise must be carefully done away with4 ,fig4 #agi4 ,,siemens ,,halske',s ,,galvanometer4 ,siemens ,halske's galvanometer is of the reflecting or mirror type 7see ,galvanometer1 ,reflecting7 with suspended1 bell-shaped magnet1 in place of the ordinary magnetic needle1 or astatic combination of the lightest possible weight in the regular instrument4 ,a copper ball drilled out to admit the magnet is used as damper in the ordinary use of the instrument4 ,to convert it into a ballistic galvanometer the copper ball is removed4 ,the heavy suspended magnet then by its inertia introduces the desired element into the instrument4 #bfh ,,standard ,,electrical ,,dictionary4 ,referring to the cut1 ,fig4 #agi1 ,m is the suspended magnet1 with north and south poles n and s2 ,s is the reflecting mirror2 r is the tube containing the suspending thread2 ,r is the damper removed for ballistic work4 ,the ballistic galvanometer is used to measure quantities of electricity in an instantaneous discharge1 which discharge should be completed before the heavy needle begins to move4 ,the extreme elongation or throw of the needle is observed1 and depends 7#a7 on the number of coulombs 7,k7 that pass during the discharge2 7#b7 on the moment of inertia of the needle and attached parts2 7#c7 on the moment of the controlling forces1 i4 e41 the forces tending to pull the needle back to zero2 7#d7 on the moment of the damping forces2 7#e7 on the moment of the deflecting forces due to a given constant current4 ,the formula is thus expressed3 ,k 7,p _/ ,,pi 7 99 ,a 99 sin7 k _/ #b 7 _/ tan7 a 7 in which ,k coulombs discharged2 ,p periodic time of vibration of needle2 ,a amperes producing a steady deflection equal to a 2 k first angular deflection of needle4 ,for accuracy k and a should both be small and the damping so slight as to be negligible4 ,otherwise a correction for the latter must be applied4 ,for approximate work for k and a the deflections read on the scale may be used with the following formula3 ,k 7,p _/ ,,pi 7 99 7 ,a _/ #b 7 99 7 k _/ a 7 ,galvanometer ,constant4 ,assume a galvanometer with a very short needle and so placed with respect to its coils that the magnetic field produced by a current circulating in them is sensibly uniform in the neighborhood of the needle1 with its lines of force at right angles thereto4 ,the field is proportional to the current i1 so that it may be denoted by ,g i4 ,then ,g is the galvanometer constant4 ,if now the angle of deflection of the needle is 8 against the earth's field ,h1 ,m being the magnetic moment of the needle we have ,g i ,m cos 8 ,h ,m sin 8 or i 7,h_/,g799 tan 84 ,h_/,g is the reduction factor2 variable as ,h varies for different places4 ,for a tangent galvanometer the constant ,g is equal to #b99,,pi997n_/a71 in which n denotes the number of turns of wire1 and a denotes the radius of the circle4 ,galvanometer1 ,differential4 ,a galvanometer in which the needle is acted on by two coils wound in opposition1 each of equal deflecting action and of equal resistance4 ,if a current is divided between two branches or parallel conductors1 each including one of the coils1 when the needle points to zero the resistances of the two branches will bc equal4 ,in the cut1 ,c ,c' represent the coils1 and ,a and ,b the two leads into which the circuit1 ,p ,q1 is divided4 #bfi ,,standard ,,electrical ,,dictionary4 ,fig4 #ahj4 ,,theory ,,of ,,differential ,,galvanometer4 ,fig4 #aha4 ,,differential ,,galvanometer4 ,galvanometer1 ,direct ,reading4 ,a calibrated galvanometer1 whose scale is graduated by volts or amperes1 instead of degrees4 ,galvanometer1 ,marine4 7,sir ,william ,thomson's47 ,a galvanometer of the reflecting type1 for use on shipboard4 ,a fibre suspension is adopted for the needle4 ,the fibre is attached to a fixed support at one end and to a spring at the other1 and the needle is suspended by its centre of gravity4 ,this secures it to a considerable extent from disturbance due to the rolling of the ship4 ,a thick iron box encloses the needle1 etc41 to cut off any magnetic action from the ship4 7,see ,galvanometer1 ,reflecting47 ,galvanometer1 ,potential4 ,a galvanometer wound with fine ,german silver wire to secure high resistance used for determination of potential difference4 ,galvanometer1 ,proportional4 ,a galvanometer so constructed that the deflections of its index are proportional to the current passing4 ,it is made by causing the deflecting force to increase as the needle is deflected1 more and more1 or by causing the restitutive force to diminish under like conditions1 or by both4 ,the condition is obtained in some cases by the shape and position of the deflecting coils4 ,galvanometer1 ,quantity4 ,a galvanometer for determining quantities of electricity1 by the deflections produced by discharging the quantities through their coils4 ,it is a ballistic galvanometer with very little or no damping4 #bgj ,,standard ,,electrical ,,dictionary4 ,fig4 #ahb4 ,,principle ,,of ,,reflecting ,,galvanometer4 ,fig4 #ahc4 ,,reflecting ,,galvanometer4 ,galvanometer1 ,reflecting4 ,a galvanometer the deflections of whose needle are read by an image projected by light reflected from a mirror attached to the needle or to a vertical wire carrying the needle4 ,a lamp is placed in front of the instrument facing the mirror4 ,the light of the lamp is reflected by the mirror upon a horizontal scale above the lamp4 ,an image of a slit or of a wire may be caused thus to fall upon the scale1 the mirror being slightly convex1 or a lens being used to produce the projection4 #bga ,,standard ,,electrical ,,dictionary4 ,if the mirror swings through a horizontal arc1 the reflected image will move1 in virtue of a simple geometrical principle1 through an arc of twice as many degrees4 ,the scale can be placed far from the mirror1 so that the ray of light will represent a weightless index of very great length1 and minute deflections of the needle will be shown distinctly upon the scale4 ,in the cut1 ,fig4 #ahb1 the ray of light from the lamp passes through the aperture1 m m1 and is made parallel by the lens1 ,l4 ,at s is the mirror attached to the needle and moving with it4 ,a scale placed at t receives the reflection from the mirror4 ,the cut1 ,fig4 #ahc1 shows one form of the instrument set up for use4 ,synonym--,mirror ,galvanometer4 ,galvanometer ,shunt4 ,to prevent too much current passing through a galvanometer 7for fear of injury to its insulation7 a shunt is sometimes placed in parallel with it4 ,the total current will be distributed between galvanometer and shunt in the inverse ratio of their respective resistances4 7,see ,multiplying ,power of a ,shunt47 #bgb ,,standard ,,electrical ,,dictionary4 ,fig4 #ahd4 ,,sine ,,galvanometer4 ,galvanometer1 ,sine4 ,a galvanometer whose measurements depend upon the sine of the angle of deflection produced when the coil and needle lie in the same vertical plane4 ,the needle1 which may be a long one1 is surrounded by a coil1 which can be rotated about a vertical axis passing through the point of suspension of the needle4 ,starting with the needle at rest in the plane of the coil1 a current is passed through the coil deflecting the needle1 the coil is swung around deflecting the needle still more1 until the needle lies in the plane of the coil2 the intensity of the current will then be in proportion to the sine of the angle through which the coil and needle move4 ,in the galvanometer ,m is a circle carrying the coil1 ,n is a scale over which the needles1 m and n1 move1 the former being a magnetic needle1 the latter an index at right angles and attached thereto2 a and b are wires carrying the current to be measured4 ,the circles1 ,m and ,n1 are carried by a base1 ,o1 around which they rotate4 ,h is a fixed horizontal graduated circle4 ,in use the circle1 ,m1 is placed in the magnetic meridian1 the current is passed through the coil1 ,m2 the needle is deflected2 ,m is turned until its plane coincides with the direction of the needle1 m4 ,the current strength is proportional to the sine of the angle of deflection4 ,this angle is measured by the vernier1 ,c1 on the circle1 ,h4 ,the knob1 ,a1 is used to turn the circle1 ,m4 #bgc ,,standard ,,electrical ,,dictionary4 ,fig4 #ahe4 ,,tangent ,,galvanometer4 ,galvanometer1 ,tangent4 ,a galvanometer in which the tangents of the angles of deflection are proportional to the currents producing such deflections4 ,for this law to apply the instrument in general must fulfill the following conditions3 7#a7 ,the needle must be controlled by a uniform magnetic field such as that of the earth2 7#b7 the diameter of the coil must be large compared to the length of the needle2 7#c7 the centre of suspension of the needle must be at the centre of the coil2 7#d7 the magnetic axis of the needle must lie in the plane of the coil when no current is passing4 ,if a single current strength is to be measured the best results will be attained when the deflection is #de2 in comparing two currents the best results will be attained when the deflections as nearly as possible are at equal distances on both sides of #de4 ,the needle should not exceed in length one-tenth the diameter of the coil4 ,for very small deflections any galvanometer follows the law of tangential deflection4 ,as for very small deflections the tangents are practically equal to the arcs subtended1 for such deflections the currents are proportional to the deflections they produce4 ,the sensibility is directly proportional to the number of convolutions of wire and inversely proportional to their diameter4 ,the tangent law is most accurately fulfilled when the depth of the coil in the radial direction is to the breadth in the axial direction as square,root7#c73square,root7#b71 or about as #aa3i4 ,galvanometer1 ,torsion4 ,a galvanometer whose needle is suspended by a long filament or by a thread and spiral spring against whose force of torsion the movements of the needle are produced4 ,the current strength is determined by bringing the needle back to its position of rest by turning a hand-button or other arrangement4 ,the angle through which this is turned gives the angle of torsion4 ,from this the current strength is calculated on the general basis that it is proportional to the angle of torsion4 ,fig4 #ahf4 ,,torsion ,,galvanometer4 #bgd ,,standard ,,electrical ,,dictionary4 ,galvanometer1 ,vertical4 ,a galvanometer whose needle is mounted on a horizontal axis and is deflected in a vertical plane4 ,one of the poles is weighted to keep it normally vertical1 representing the control4 ,it is not used for accurate work4 ,synonym--,upright ,galvanometer4 ,fig4 #ahg4 ,,vertical ,,galvanometer4 ,galvanometer1 ,volt- and ,ampere-meter4 ,a galvanometer of ,sir ,william ,thomson's invention embodying the tangent principle1 and having its sensibility adjustable by moving the magnetic needle horizontally along a scale 7the meter7 towards or away from the coil4 ,a curved magnet is used to adjust the control4 ,the leads are twisted to prevent induction4 ,the instrument is made with a high resistance coil for voltage determinations1 and with a low resistance coil for amperage determinations4 ,at one end of a long base board a vertical coil with its plane at right angles to the axis of the board is mounted4 ,a scale 7the meter of the name7 runs down the centre of the board4 ,a groove also runs down the centre4 ,the magnetic needle is contained in a quadrant-shaped glass-covered box which slides up and down the groove4 ,a number of short parallel needles mounted together1 with an aluminum pointer are used4 ,fig4 #ahh4 ,,sir ,,william ,,thomson',s ,,ampere-,,meter ,,galvanometer4 #bge ,,standard ,,electrical ,,dictionary4 ,in the cut ,p is the base board1 ,m is a glass covered case containing the magnetic needle1 and sliding along the base board1 being guided by the central groove1 ,c1 is the coil4 ,between the coil and the needle is the arched or bent controlling magnet4 ,the long twisted connecting wires are seen on the right hand4 ,galvano-plastics4 ,the deposition of metals by electrolysis1 a disused term replaced by electro-deposition1 electroplating1 and electro-metallurgy4 ,galvano-puncture4 ,an operation in medical electricity4 7,see ,electro-puncture47 ,galvanoscope4 ,an instrument1 generally of the galvanometer type1 used for ascertaining whether a current is flowing or not4 ,any galvanoscope1 when calibrated1 if susceptible thereof1 becomes a galvanometer4 ,gas1 ,electrolytic4 ,gas produced by the decomposition1 generally of water1 by electrolysis4 ,it may be hydrogen or oxygen1 or a mixture of the two1 according to how it is collected4 7,see ,gases1 ,mixed47 ,gases1 ,mixed4 ,the mixture of approximately one volume of oxygen and two volumes of hydrogen collected in the eudiometer of a gas voltameter or other electrolytic apparatus4 ,gassing4 ,the evolution of gas from the plates of a storage battery in the charging process1 due to too high voltage in the circuit of the charging dynamo4 ,gastroscope4 ,an apparatus for illuminating by an incandescent lamp the interior of the stomach1 and with prisms to refract the rays of light so that the part can be seen4 ,the stomach is inflated with air1 if desirable1 to give a better view4 ,an incandescent platinum spiral in a water jacket has been employed for the illumination4 ,gassiot's ,cascade4 ,a goblet lined for half its interior surface with tinfoil4 ,it is placed in the receiver of an air pump from the top of whose bell a conductor descends into it1 not touching the foil4 ,on producing a good rarefaction1 and discharging high tension electricity from between the conductor just mentioned and the metal of the machine1 a luminous effect is produced1 as if the electricity1 pale blue in color1 was overflowing the goblet4 ,gauss4 ,a name suggested for unit intensity of magnetic field4 ,sylvanus ,p4 ,thomson proposed for its value the intensity of a field of #a;,e#h ,c4 ,g4 ,s4 electro-magnetic units4 ,j4 ,a4 ,fleming proposed the strength of field which would develop one volt potential difference in a wire #a;,e#f centimeters long1 moving through such field with a velocity of one centimeter per second4 ,this is one hundred times greater than ,thomson's standard4 ,sir ,william ,thomson suggested the intensity of field produced by a current of one ampere at a distance of one centimeter ,the gauss is not used to any extent2 practical calculations are based on electro-magnetic lines of force4 #bgf ,,standard ,,electrical ,,dictionary4 ,gauss' ,principle4 ,an electric circuit acts upon a magnetic pole in such a way as to make the number of lines of force that pass through the circuit a maximum4 ,fig4 #ahi4 ,,gauss' ,,tangent ,,position4 ,gauss1 ,tangent ,positions of4 ,the end on and broadside methods of determining magnetization involve positions which have been thus termed4 7,see ,broadside ,method and ,end on ,method47 ,gear1 ,magnetic ,friction4 ,friction gear in which the component wheels are pressed against each other by electromagnetic action4 ,in the cut1 repeated from ,adherence1 ,electro-magnetic1 the magnetizing coil makes the wheels1 which are of iron1 press strongly together4 ,fig4 #aij4 ,,magnetic ,,friction ,,gear4 #bgg ,,standard ,,electrical ,,dictionary4 ,geissler ,tubes4 ,sealed tubes of glass containing highly rarefied gases1 and provided with platinum electrodes extending through the glass tightly sealed as they pass through it1 and often extending a short distance beyond its interior surface4 ,on passing through them the static discharge luminous effects are produced varying with the degree of exhaustion1 the contents 7gas71 the glass itself1 or solutions surrounding it4 ,the two latter conditions involve fluorescence phenomena often of a very beautiful description4 ,the pressure of the gas is less than one-half of a millimeter of mercury4 ,if a complete vacuum is produced the discharge will not pass4 ,if too high rarefaction is produced radiant matter phenomena 7see ,radiant ,state7 occur4 ,geissler tubes have been used for lighting purposes as in mines1 or for illuminating the interior cavities of the body in surgical or medical operations4 ,generating ,plate4 ,the positive plate in a voltaic couple1 or the plate which is dissolved2 generally a plate of zinc4 ,synonyms--,positive ,plate--,positive ,element4 ,generator1 ,current4 ,any apparatus for maintaining an electric current4 ,it may be as regards the form of energy it converts into electrical energy1 mechanical1 as a magneto or dynamo electric machine or generator2 thermal1 as a thermo-electric battery2 or chemical1 as a voltaic battery2 all of which may be consulted4 ,generator1 ,secondary4 ,a secondary or storage battery4 7,see ,battery1 ,secondary47 ,german ,silver4 ,an alloy of copper1 #b parts1 nickel1 #a part1 and zinc1 #a part4 ,owing to its high resistance and moderate cost and small variation in resistance with change of temperature1 it is much used for resistances4 ,from ,dr4 ,mathiessen's experiment the following constants are deduced in legal ohms3 ,relative ,resistance 7,silver #a71 #ac4ib ,specific ,resistance at #j ,c4 7#cb;,f471 #bj4ic microhms4 ,resistance of a wire1 7a7 #a foot long1 weighing #a grain1 #b4fbb ohms4 #a foot long1 #a_/ajjj inch thick1 #abe4ia #a meter long1 weighing #a gram1 #a4hcj #a meter long1 #a millimeter thick1 #j4bfff ,resistance of a #a inch cube at #j;,c4 7#cb ,f471 #h4bdj microhms4 ,approximate percentage increase of resistance per #a ,c4 7#a4h ,f47 at about #bj ,c4 7#fh ,f471 #j4jdd per cent4 ,gilding1 ,electro-4 ,the deposition of gold by an electric current1 or electrolytically in the electroplating bath4 ,gilding ,metal4 ,a special kind of brass1 with a high percentage of copper1 used to make objects which are to be gilded by electrolysis4 #bgh ,,standard ,,electrical ,,dictionary4 ,gimbals4 ,a suspension used for ships' compasses and sometimes for other apparatus4 ,it consists of a ring held by two journals1 so as to bc free to swing in one plane4 ,the compass is swung upon this ring1 being placed concentrically therewith4 ,its journals are at right angles to those of the ring4 ,this gives a universal joint by which the compass1 weighted below its line of support1 is always kept horizontal4 ,fig4 #aia4 ,,compass ,,suspended ,,in ,,gimbals4 ,glass4 ,a fused mixture of silicates of various oxides4 ,it is of extremely varied composition and its electric constants vary greatly4 ,many determinations of its specific resistance have been made4 ,for flint glass at #ajj ,c4 7#bab ,f47 about 7#b4jf;,e#ad7 ohms --at #fj ,c 7#adj ,f47 7#a4jbj;,e#ae7 7,thomas ,gray7 is given1 while another observer 7,beetz7 gives for glass at ordinary temperatures an immeasurably high resistance4 ,it is therefore a non-conductor of very high order if dry4 ,as a dielectric the specific inductive capacity of different samples of flint glass is given as #f4eg--f4he--g4d--aj4a 7,hopkinson71 thus exceeding all other ordinary dielectrics4 ,the densest glass1 other things being equal1 has the highest specific inductive capacity4 ,gold4 ,a metal1 one of the elements2 symbol ,au4 c 42 atomic weight1 #aif4h2 equivalent1 #fe4f2 valency1 #c2 specific gravity #ai4e4 ,it is a conductor of electricity4 ,annealed4 ,hard drawn4 ,relative ,resistance 7,annealed ,silver #a71 #a4cfi #a4cic ,specific ,resistance1 #b4jeh #b4jid ,resistance of a wire at #j ,c4 7#cb;,f47 7a7 #a foot long1 weighing #a grain1 #eg4he #eh4hd ohms 7b7 #a foot long1 #a_/ajjj inch thick1 #ab4ch #ab4fj 7c7 #a meter long1 weighing #a gram1 4#djce 4#dajd 7d7 #a meter long1 #a millimeter thick1 4#jbfbj 4#jbffh ,resistance of a #a inch cube at #j ,c47#cb ,f47 4#hajb 4#hbdg ,approximate increase in resistance per #j ,c41 7#a4h ,f7 at about #bj ,c4 7#fh ,f471 #j4cfe per cent4 ,electro-chemical equivalent 7,hydrogen 4#jaje71 4#fhhh #bgi ,,standard ,,electrical ,,dictionary4 ,gold ,bath4 ,a solution of gold used for depositing the metal in the electroplating process4 ,a great number of formulae have been devised1 of which a few representative ones are given here4 ,,cold ,,baths4 ,,hot ,,baths4 ,water1 #aj1jjj #aj1jjj #aj1jjj #aj1jjj #e1jjj #c1jjj ,potassium ,cyanide1 #bjj -- #bjj #aj -- #ej ,gold1 #ajj #ae #ajj #aj #aj #aj ,potassium ,ferrocyanide1 -- #bjj -- -- #aej -- ,potassium ,carbonate1 -- #aej -- -- #ej -- ,ammonium ,chloride1 -- #cj -- -- #bj -- ,aqua ,ammoniae1 -- -- #ejj -- -- -- ,sodium ,phosphate1 -- -- -- #fjj -- -- ,sodium ,bisulphite1 -- -- -- #ajj -- -- 7,roseleur47 ,in the baths the gold is added in the form of neutral chloride1 ,auric chloride 7,au ,cl#f74 ,gold ,stripping ,bath4 ,a bath for removing gold from plated articles without dissolving the base in order to save the precious metal4 ,a bath of #aj parts of potassium cyanide and #ajj parts of water may be used1 the articles to be stripped being immersed therein as the anode of an active circuit4 ,if the gilding is on a silver or copper basis1 or on an alloy of these metals the same solution attacks the base and dissolves it1 which is objectionable4 ,for silver articles it is enough to heat to cherry red and throw into dilute sulphuric acid4 ,the gold scales off in metallic spangles4 ,for copper articles1 a mixture of #aj volumes concentrated sulphuric acid1 #a volume nitric acid1 and #b volumes hydrochloric acid may be used by immersion only1 or with a battery4 ,the sulphuric acid in such large excess is supposed to protect the copper4 ,for copper articles concentrated sulphuric acid alone with the battery may be used4 ,this does not sensibly attack the copper if it is not allowed to become diluted4 ,even the dampness of the air may act to dilute it4 ,graduator4 ,apparatus for enabling the same line to be used for telegraph signals and telephoning4 ,one type consists in coils with iron cores or simply electromagnets4 ,these act to retard the current in reaching its full power and also prolong it4 ,this gives a graduated effect to the signals1 so that the telephone diaphragm is not audibly affected by the impulses4 ,the telephoning current is so slight and so rapid in its characteristic changes that it is without effect upon the ordinary telegraph4 #bhj ,,standard ,,electrical ,,dictionary4 ,gram4 ,the unit of weight in the metric system2 accepted as the unit of mass in the absolute of ,c4 ,g4 ,s4 system of units4 ,it is the one-thousandth part of mass of a standard weight preserved under proper conditions in ,paris1 and supposed to be the mass of a cubic decimeter of distilled water at the temperature of the maximum density of water4 ,the standard is the kilogram2 the temperature is #c4i ,c4 7#ci ,f474 ,the standard kilogram is found to be not exactly the weight of a cubic decimeter of water1 the latter weighing #a4jjjjac kilogram4 ,if therefore the defined gram on the water basis is taken as the unit it varies very slightly from the accepted gram4 #a gram is equal to #ae4dcbcdhgd grains4 7,prof4 ,w4 ,h4 ,miller47 ,gram-atom4 ,the number of grams of an element equal numerically to the atomic weight1 as #af grams of oxygen1 #a gram of hydrogen1 #ce4e grams of chlorine2 all which might be expressed as gram-atoms of oxygen1 hydrogen and chlorine respectively4 ,the gram-atom approximately expresses the number of gram-calories required to heat one gram of the substance #a ,c4 7#a4h ,f474 ,this is in virtue of ,dulong and ,petit's discovery that the atomic weight of an element multiplied by its specific heat gives approximately a constant for all elements4 ,transcriber's note3 ,a gram-atom is the mass1 in grams1 of one mole of atoms in a monatomic element4 ,a mole consists of ,avogadro's number of atoms1 approximately #f4jbbad;,e#bc4 ,gram-molecule4 ,the number of grams of a substance equal numerically to its molecular weight4 ,graphite4 ,carbon2 one of three allotropic modifications of this element4 ,it occurs in nature as a mineral4 ,it is used as a lubricant for machinery2 for commutator brushes2 for making surfaces to be plated conductive1 and for mixing with manganese binoxide in ,leclanch cells4 ,gravitation4 ,a natural force which causes all masses of matter to attract each other4 ,its cause is unknown2 it is often supposed to be due to the luminiferous ether4 ,transcriber's note3 ,einstein's explanation of gravity1 ,general ,relativity and the curvature of space-time1 came #bc years later1 #aiae4 #bha ,,standard ,,electrical ,,dictionary4 ,gravity1 ,acceleration of4 ,the velocity imparted to a body in one second by the action of gravitation at any standard point upon the earth's surface in a vacuum4 ,this will vary at different places1 owing principally to the variation in centrifugal force due to the earth's rotation4 ,for standard valuation it must be reduced to sea level4 ,the following are examples of its variation3 ,equator1 #igh4ajbh centimeters per second ,paris1 #ihj4id ,greenwich #iha4;,i#g ,edinburgh1 #iha4ed ,pole 7,n4 or ,s471 #ihc4ajhd 7theoretical7 ,as round numbers for approximate calculations #iha centimeters or #cb4b feet may be employed4 ,transcriber's note3 ,the acceleration of gravity at the equator is also reduced by the increased distance from the center of the earth 7equatorial bulge74 ,increased altitude reduces gravity4 ,reduced air density at altitude reduces buoyancy and increases apparent weight4 ,local variations of rock density affects gravity4 ,gravity1 ,control4 ,control by weight4 ,in some ammeters and voltmeters gravity is the controlling force4 ,grid4 ,a lead plate perforated or ridged for use in a storage battery as the supporter of the active materials and in part as contributing thereto from its own substance4 ,ground4 ,the contact of a conductor of an electric circuit with the earth1 permitting the escape of current if another ground exists4 ,ground-wire4 ,a metaphorical term applied to the earth when used as a return circuit4 ,fig4 #aib4 ,,grove',s ,,gas ,,battery4 ,grove's ,gas ,battery4 ,a voltaic battery depending for its action on the oxidation of hydrogen instead of the oxidation of zinc4 ,its action is more particularly described under ,battery1 ,gas4 ,in the cut ,b1 ,b#a 99 99 99 are the terminals of the positive or hydrogen electrodes1 marked ,h1 and ,a1 ,al 99 99 99 are the terminals of the negative or oxygen electrodes marked ,o1 while ,m1 ,m#a 99 99 99 is dilute sulphuric acid4 #bhb ,,standard ,,electrical ,,dictionary4 ,guard ,ring4 ,an annular horizontal surface surrounding the balanced disc in the absolute electrometer4 7,see ,electrometer1 ,absolute47 ,guard ,tube4 ,a metal tube surrounding a dry pile used with a quadrant electrometer1 or other electrometers of that type4 ,it prevents the capacity of the lower brass end of the pile 7which brass end closes the glass tube containing the discs7 from momentary change by approach of some conductor connected to the earth4 ,there are other guard tubes also4 ,gun1 ,electro-magnetic4 ,an electro-magnet with tubular core4 ,if1 when it is excited a piece of an iron rod is pushed into the central aperture of the core and is released1 the magnetic circle will try to complete itself by pushing the rod out so that it can thus be discharged1 as if from a popgun4 ,synonym--,electric ,popgun4 ,fig4 #aic4 ,,electric ,,popgun4 ,gutta ,percha4 ,the hardened milky juice of a tree1 the ,isonandra gutta1 growing in ,malacca and other parts of the ,eastern ,archipelago4 ,it is much used as an insulator or constituent of insulators4 ,resistance after several minutes electrification per #a centimeter cube at #ed ,c4 7#ge ,f471 #d4ej;,e#ad ohms4 ,the specific resistance varies--from #b4e;,e#ac to #e4j;,e#ad ohms4 ,a usual specification is #b4j;,e#ad ohms4 ,the influence of temperature on its resistance is given in ,clark ,bright's empirical formula1 ,r ,r#j at1 in which ,r is the resistance at temperature t ,c--,ro the resistance at #j ,c 7#cb ,f71 a is the coefficient 4#hidd4 ,the resistance increases with the time of passage of the current1 the variation being less the higher the temperature4 #bhc ,,standard ,,electrical ,,dictionary4 ,time of ,relative ,resistance ,relative ,resistance ,electrification4 at #j ,c 7#cb ,f47 at #bd ,c 7#ge ,f47 #a minute #ajj #e4ea #b #abg4i #f4 #e #afc4a #f4ff #aj #aij4i #f4id #bj #bcj4h #g4ch #cj #bej4f #g4dd #fj #bij4d #g4f #ij #cah4c #g4ff ,in cable testing one minute is generally taken as the time of electrification4 ,pressure increases the resistance by the formula ,rp,r 7#a 4#jjcbg ,p7 in which ,rp is the resistance at pressure p--,r resistance at atmospheric pressure--p pressure in atmospheres4 ,thus in the ocean at a depth of #d1jjj meters 7#b4dhee miles71 the resistance is more than doubled4 ,the longer the pressure is applied1 the greater is the resistance4 ,the specific inductive capacity of gutta percha is #d4b4 ,good gutta percha should not break when struck with a hammer1 should recover its shape slowly1 and it should support much more than #cjj times its own weight4 ,gyrostatic ,action of ,armatures4 ,owing to gyrostatic action a rotating armature resists any change of direction of its axis4 ,on ships and in railway motors which have to turn curves this action occurs4 ,a #adh lb4 armature running at #a1cjj revolutions per minute may press with #cj lbs4 on each journal as the ship rolls through an angle of #bj in #af seconds4 ,h4 7a7 ,the symbol for the horizontal component of the earth's magnetization4 7b7 ,the symbol for the intensity of a magnetizing force or field4 ,the symbol ,h1 as it is generally used1 may mean either the number of dynes which act upon a unit pole1 or the number of lines of force per centimeter4 7c7 ,the symbol for the unit of self-induction4 ,hair1 ,removal of1 by ,electrolysis4 ,a method of depilation by destruction of individual hair follicles by electrolysis4 ,a fine platinum electrode is thrust into a hair follicle4 ,it is the negative electrode4 ,the positive electrode is in contact with the body of the person under treatment2 it is often a sponge electrode simply held in his hand4 ,a current of two to four milliamperes from an ,e4 ,m4 ,f4 of #ae to #bj volts1 is passed4 ,this destroys the follicle1 the hair is removed and never grows again4 ,a gradual increase of current is advised for the face4 ,as only one hair is removed at once1 but a small number are taken out at a sitting4 #bhd ,,standard ,,electrical ,,dictionary4 ,haldat's ,figures4 ,with a pole of a strong bar magnet1 used like a pencil1 imaginary figures are drawn upon a hard steel plate1 such as a saw-blade4 ,the pattern is gone over several times4 ,by dusting iron filings on a sheet of paper laid over the steel plate1 while horizontal1 very complicated magnetic figures are produced4 ,hall's ,experiment4 ,a cross of thin metal1 such as gold leaf1 is secured upon a pane of glass4 ,to two opposite arms a battery is connected in circuit with them4 ,to the other two arms a galvanometer is connected in circuit4 ,if the cross is put into a field of force whose lines are perpendicular thereto1 the galvanometer will disclose a constant current4 ,the current is pushed1 as it were1 into the galvanometer circuit4 ,other metals have been used with similar results4 ,they must be thin or the experiment fails4 ,if the arm receiving the battery current is horizontal1 and if it flows from left to right1 and if the lines of force go from downward through the cross1 the current in the galvanometer circuit will flow from the observer through the other arms of the cross1 if the cross is of gold1 silver1 platinum or tin1 and the reverse if of iron4 ,the experiment has indicated a possible way of reaching the velocity of electricity in absolute measure4 ,hall ,effect4 ,the effect observed in ,hall's experiment1 q4 v4 ,hall ,effect1 ,real4 ,a transverse electro-motive force in a conductor through which a current is passing produced by a magnetic field4 ,hall ,effect1 ,spurious4 ,a spurious electro-motive force produced in a conductor1 through which a current is passing by changes in conductivity of the conductor brought about by a magnetic field4 ,hanger ,board4 ,a board containing two terminals1 a suspending hook1 and a switch1 so that an arc lamp can be introduced into a circuit thereby1 or can be removed as desired4 ,harmonic ,receiver4 ,a receiver containing a vibrating reed1 acted on by an electro-magnet4 ,such a reed answers only to impulses tuned to its own pitch4 ,if such are received from the magnet it will vibrate4 ,impulses not in tune with it will not affect it4 7,see ,telegraph1 ,harmonic47 ,head ,bath1 ,electric4 ,a fanciful name for an electro-medical treatment of the head4 ,the patient is insulated by an insulating stool or otherwise4 ,his person is connected with one terminal of an influence machine4 ,an insulated metallic circle1 with points of metal projecting inward or downward1 is placed about the head4 ,the circle is connected with the other pole of the machine4 ,on working it a silent or brush discharge with air convection streams occurs between the patient's head and the circle of points4 #bhe ,,standard ,,electrical ,,dictionary4 ,head-light1 ,electric4 ,an electric head-light for locomotives has been experimented with4 ,it includes the parabolic reflection of the regular light with an arc-lamp in place of the oil lamp4 ,an incandescent lamp may be used in the same place1 but has no great advantage over oil as regards illuminating power4 ,heat4 ,a form of kinetic energy1 due to a confused oscillatory movement of the molecules of a body4 ,heat is not motion1 as a heated body does not change its place2 it is not momentum1 but it is the energy of motion4 ,if the quantity of molecular motion is doubled the momentum of the molecules is also doubled1 but the molecular mechanical energy or heat is quadrupled4 ,as a form of energy it is measured by thermal units4 ,the calorie is the most important1 and unfortunately the same term applies to two units1 the gram-degree ,c4 and the kilogram-degree ,c4 7,see ,calorie47 ,calories are determined by a calorimeter1 q4 v4 ,independent of quantity of heat a body may be hotter or colder4 ,thermometers are used to determine its temperature4 ,heat is transmitted by conduction1 a body conducting it slowly for some distance through its own substance4 ,bodies vary greatly in their conductivity for heat4 ,it is also transmitted by convection of gases or liquids1 when the heated molecules traveling through the mass impart their heat to other parts4 ,finally it is transmitted by ether waves with probably the speed of light4 ,this mode of transmission and the phenomena of it were attributed to radiant heat4 ,as a scientific term this is now dropped by many scientists4 ,this practice very properly restricts the term heat to kinetic molecular motion4 ,the mechanical equivalent of heat is the number of units of work which the energy of one unit quantity of heat represents4 7,see ,equivalents1 ,mechanical and ,physical47 ,heat1 ,atomic4 ,the product of the specific heat of an element by its atomic weight4 ,the product is approximately the same for all the elements1 and varies as determined between #e4ci and #f4hg4 ,the variations are by some attributed principally to imperfection of the work in determining them4 ,the atomic heat represents the number of gram calories required to raise the temperature of a gram atom 7a number of grams equal numerically to the atomic weight7 one degree centigrade4 #bhf ,,standard ,,electrical ,,dictionary4 ,heat1 ,electric4 ,this term has been given to the heat produced by the passage of a current of electricity through a conductor4 ,it is really electrically produced heat1 the above term being a misnomer4 ,the rise of temperature produced in a cylindrical conductor by a current depends upon the diameter of the conductor and on the current4 ,the length of the wire has only the indirect connection that the current will depend upon the resistance and consequently upon its length4 ,the quantity of heat produced in a conductor by a current is in gram-degree ,c4 units equal to the product of the current1 by the electro-motive force or potential difference maintained between the ends of the wire1 by 4#bd4 ,the cube of the diameter of a wire for a given rise of temperature produced in such conductor by a current is equal approximately to the product of the square of the current1 by the specific resistance 7q4 v47 of the material of the conductor1 by 4#jjjcia1 the whole divided by the desired temperature in centigrade units4 ,heat1 ,electrical ,convection of4 ,a term applied to the phenomena included under the ,thomson effect1 q4 v41 the unequal or differential heating effect produced by a current of electricity in conductors whose different parts are maintained at different temperatures4 ,heater1 ,electric4 ,an apparatus for converting electrical energy into thermal energy4 ,an incandescent lamp represents the principle1 and in the ,edison meter has been used as such to maintain the temperature of the solutions4 ,heaters for warming water and other purposes have been constructed1 utilizing conductors heated by the passage of the current as a source of heat4 7,see also ,heating ,magnet47 ,heating ,error4 ,in voltmeters the error due to alteration of resistance of the coil by heating4 ,if too strong a current is sent through the instrument1 the coils become heated and their resistance increased4 ,they then do not pass as much current as they should for the potential difference to which they may be exposed4 ,their readings then will be too low4 ,one way of avoiding the trouble is to have a key in circuit1 and to pass only an instantaneous or very brief current through the instrument and thus get the reading before the coils have time to heat4 ,the heating error does not exist for ammeters1 as they are constructed to receive the entire current1 and any heating error within their range is allowed for in the dividing of the scale4 ,heating ,magnet4 ,an electro-magnet designed to be heated by ,foucault currents induced in its core by varying currents in the windings4 ,it has been proposed as a source of artificial heat1 a species of electric heating apparatus for warming water1 or other purposes4 #bhg ,,standard ,,electrical ,,dictionary4 ,heat1 ,irreversible4 ,the heat produced by an electric current in a conductor of identical qualities and temperature throughout4 ,such heat is the same whatever the direction of the current4 ,the heating effect is irreversible because of the absence of the ,thomson effect1 q4 v47 or ,peltier effect1 q4 v4 ,heat1 ,mechanical ,equivalent of4 ,the mechanical energy corresponding to a given quantity of heat energy4 ,mechanical energy is generally represented by some unit of weight and height1 such as the foot-pound2 and heat energy is represented by a given weight of water heated a given amount1 such as a pound-degree centigrade4 ,joule's equivalent is usually accepted2 it states that #ggb4ee foot pounds of mechanical energy are equivalent to #a pound-degree ,f4 7one pound avds4 of water raised in temperature one degree ,fahrenheit74 ,other equivalencies have also been deduced4 ,heat1 ,molecular4 ,the product of a specific heat of the compound by its molecular weight4 ,it is approximately equal to the sum of the atomic heats of its constituent elements4 ,the molecular heat represents the number of gram calories required to raise the temperature of a gram-molecule 7a number of grams equal numerically to the molecular weight7 one degree centigrade4 ,the molecular heat is approximately equal for all substances4 ,heat1 ,specific4 ,the capacity of a body for heat2 a coefficient representing the relative quantity of heat required to raise the temperature of an identical weight of a given body a defined and identical amount4 ,the standard of comparison is water2 its specific heat is taken as unity4 ,the specific heats by weight of other substances are less than unity4 ,the specific heat varies with the temperature4 ,thus the specific heat of water is more strictly #a4jjjae t ,c4 ,specific heat is greater when a substance is in the liquid than when it is in the solid state4 ,thus the specific heat of ice is #j4dhi2 less than half that of water4 ,it differs with the allotropic modifications of bodies2 the specific heat of graphite is 4#bjb2 of diamond1 4#adg4 ,the product of the specific heat by the atomic weight of elements gives a figure approximately the same4 ,a similar law applies in the case of molecules4 7,see ,heat1 ,atomic-,heat1 ,molecular47 ,the true specific heat of a substance should be separated from the heat expended in expanding a body against molecular and atomic forces1 and against the atmospheric pressure4 ,so far this separation has not been possible to introduce in any calculations4 #bhh ,,standard ,,electrical ,,dictionary4 ,heat1 ,specific1 of ,electricity4 ,a proposed term to account for the heat absorbed or given out in unhomogeneous conductors1 by the ,thomson effect1 or ,peltier effect 7see ,effect1 ,thomson--,effect1 ,peltier47 ,if a current of electricity be assumed to exist1 then under the action of these effects it may be regarded as absorbing or giving out so many coulombs of heat1 and thus establishing a basis for specific heat4 ,heat ,units4 ,the ,british unit of heat is the pound degree ,f--the quantity of heat required to raise the temperature of a pound of water from #cb to #cc ,f4 ,the ,c4 ,g4 ,s4 unit is the gram-degree ,c42 another metric unit is the kilogram-degree ,c4 ,the latter is the calorie2 the former is sometimes called the small calorie or the joule2 the latter is sometimes called the large calorie4 ,the term joule is also applied to a quantity of heat equivalent to the energy of a watt-second or volt-coulomb4 ,this is equal to 4#bdl gram degree calorie4 ,hecto4 ,a prefix to terms of measurement--meaning one hundred times1 as hectometer1 one hundred meters4 ,heliograph4 ,an apparatus for reflecting flashes of light to a distant observer4 ,by using the ,morse telegraph code messages may thus be transmitted long distances4 ,when possible the sun's light is used4 ,helix4 ,a coil of wire2 properly a coil wound so as to follow the outlines of a screw without overlaying itself4 ,fig4 #aid4 ,,left-,,handed ,,helix4 ,fig4 #aie4 ,,right-,,handed ,,helix4 ,henry4 ,the practical unit of electro-magnetic or magnetic inductance4 ,it is equal to #a;,e#i ,c4 ,g4 ,s41 or absolute units of inductance4 ,as the dimensions of inductance are a length the henry is equal to #a;,e#i centimeters1 or approximately to one quadrant of the earth measured on the meridian4 ,synonyms--,secohm--,quadrant--,quad4 #bhi ,,standard ,,electrical ,,dictionary4 ,hermetically ,sealed4 ,closed absolutely tight4 ,glass vessels1 such as the bulbs of incandescent lamps1 are hermetically sealed often by melting the glass together over any opening into their interior4 ,heterostatic ,method4 ,a method of using the absolute or attracted disc electrometer4 7,see ,electrometer ,absolute47 ,the formula for its idiostatic use1 q4 v41 involves the determination of d1 the distance between the suspended and fixed discs4 ,as this is difficult to determine the suspended disc and guard ring may be kept at one potential and the lower fixed disc is then connected successively with the two points whose potential difference is to be determined4 ,their difference is determined by the difference between d and d'1 the two distances between the discs4 ,this difference is the distance through which the micrometer screw is moved4 ,the heterostatic formula is3 ,v' - ,v 7d' - d799 square,root7 #h99,,pi99,f _/ ,s 7 in which ,v and ,v' are potentials of the two points2 d' and d the two distances between the discs necessary for equilibrium2 ,s the area of the disc and ,f the force of attraction in dynes4 7,see ,idiostatic ,method47 ,high ,bars of ,commutator4 ,commutator bars1 which in the natural wear of the commutator1 project beyond the others4 ,the surface then requires turning down1 as it should be quite cylindrical4 ,high ,frequency4 ,a term used as a noun or as an adjective to indicate in an alternating current1 the production of a very great number of alternations per unit of time--usually expressed as alternations per second4 ,hissing4 ,a term applied to a noise sometimes produced by a voltaic arc2 probably due to the same cause as frying1 q4 v4 ,hittorf's ,solution4 ,a solution used as a resistance4 ,it is a solution of cadmium iodide in amylic alcohol4 ,ten per cent4 of the salt is used4 ,it is contained in a tube with metallic cadmium electrodes4 7,see ,resistance1 ,hittorf' s47 ,fig4 #aif4 ,,hittorf',s ,,resistance ,,tube4 #bij ,,standard ,,electrical ,,dictionary4 ,holders4 7a7 ,the adjustable clamps for holding the armature brushes of dynamos and motors4 7b7 ,the clamps for holding the carbons of arc lamps4 7c7 ,the clamps for holding safety fuses1 q4 v4 7d7 ,holders for ,jablochkoff candles and other electric candles4 7,see ,candle ,holders47 7e7 ,a box or block of porcelain for holding safety fuses4 ,hood4 ,a tin hood placed over an arc-lamp4 ,such hoods are often truncated cones in shape1 with the small end upwards4 ,they reflect a certain amount of light besides protecting the lamp to some extent from rain4 ,horns4 ,the extensions of the pole pieces of a dynamo or motor4 7,see ,following ,horns-,leading ,horns47 ,synonym--,pole ,tips4 ,horse ,power4 ,a unit of rate of work or activity4 ,there are two horse powers4 ,the ,british horse power is equal to #cc1jjj pounds raised one foot per minute1 or #eej foot pounds per second1 or #a4jach metric horse power4 ,the metric horse power 7,french7 is equal to #ge kilogram-meters1 or #edb foot pounds per second1 or 4#ihfcef ,british horse power4 ,h4 ,p4 is the abbreviation for horse power4 7,see ,horse ,power1 ,electric47 ,horse ,power1 ,actual4 ,the rate of activity of a machine1 as actually developed in condition for use4 ,it is less than the indicated or total horse power1 because diminished by the hurtful resistances of friction1 and other sources of waste4 ,it is the horse power that can be used in practise1 and which in the case of a motor can be taken from the fly-wheel4 ,horse ,power1 ,electric4 ,the equivalent of a mechanical horse power in electric units1 generally in volt-amperes or watts2 #gde4idc watts are equivalent to the activity of one ,british horse power2 #gce4ge are equivalent to one metric horse power4 ,the number #gdf is usually taken in practical calculations to give the equivalency4 ,transcriber's note3 ,contemporary values are3 ,mechanical 7,british7 horsepower #gde4fiii ,watts2 ,metric horsepower #gce4dihge ,watts ,horse ,power1 ,indicated4 ,the horse power of an engine as indicated by its steam pressure1 length of stroke1 and piston area1 and vacuum1 without making any deduction for friction or hurtful resistances4 ,the steam pressure is in accurate work deduced from indicator diagrams4 ,horse ,power1 ,hour4 ,a horse power exerted for one hour1 or the equivalent thereof4 ,as the horse power is a unit of activity1 the horse power hour is a unit of work or of energy4 ,it is equal to #a1ihj1jjj foot pounds4 ,h4 ,p4 ,abbreviation for horse power4 #bia ,,standard ,,electrical ,,dictionary4 ,hughes' ,electro-magnet4 ,a horseshoe electro-magnet with polarized core4 ,it is made by mounting two bobbins of insulated wire on the ends of a permanent horseshoe magnet4 ,it was devised for use in ,hughes' printing telegraph1 where very quick action is required4 ,the contact lasts only 4#jec second1 #ahe letters being transmitted per minute4 ,fig4 #aig ,,hughes' ,,electro-,,magnet4 ,fig4 #aih4 ,,hughes' ,,induction ,,balance4 ,hughes' ,induction ,balance4 ,an apparatus for determining the presence of a concealed mass of metal4 ,the apparatus is variously connected4 ,the cut shows a representative form2 a and a' are two primary coils1 each consisting of #ajj meters 7#cbh feet7 of ,no4 #cb silk covered copper wire 7#j4jji inch diameter7 wound on a boxwood spool ten inches in depth2 b and b' are secondary coils4 ,all coils are supposed to be alike4 ,the primary coils are joined in series with a battery of three or four ,daniell cells4 ,a microphone m is included in the same circuit4 ,the secondary coils are joined in series with a telephone and in opposition with each other4 ,the clock is used to produce a sound affecting the microphone4 ,if all is exactly balanced there will be no sound produced in the telephone4 ,this balance is brought about by slightly varying the distance of one of the secondaries from the primary1 until there is no sound in the telephone4 ,if now a piece of metal is placed within either of the coils1 it disturbs the balance and the telephone sounds4 #bib ,,standard ,,electrical ,,dictionary4 ,to measure the forces acting a sonometer or audiometer is used4 ,this is shown in the upper part of the cut4 ,two fixed coils1 c and e are mounted at the ends of a graduated bar4 ,a movable coil d is connected in the telephone circuit2 c and e by a switch can be connected with the battery and microphone circuit1 leaving out the induction balance coils4 ,the ends of the coils c and e1 facing each other are of the same polarity4 ,if these coils1 c and e1 were equal in all respects1 no sound would be produced when d was midway between them4 ,but they are so wound that the zero position for d is very near one of them1 c4 ,assume that a balance has been obtained in the induction balance with the coil d at zero4 ,no sound is heard whether the switch is moved to throw the current into one or the other circuit4 ,a piece of metal placed in one of the balance coils will cause the production of a sound4 ,the current is turned into the sonometer and d is moved until the same sound1 as tested by rapid movements of the switch1 is heard in both circuits4 ,the displacement of d gives the value of the sound4 ,a milligram of copper is enough to produce a loud sound4 ,two coins can be balanced against each other1 and by rubbing one of them1 or by breathing on one of them1 the balance will be disturbed and a sound will be produced4 ,prof4 ,hughes has also dispensed with the audiometer4 ,he has used a strip of zinc tapering from a width of #d mm4 74#af inch7 at one end to a sharp edge or point at the other4 ,the piece to be tested being in place in one coil1 the strip is moved across the face of the other until a balance is obtained4 ,as possible uses the detection of counterfeit coins1 the testing of metals for similarity of composition and the location of bullets in the body have been suggested4 ,care has to be taken that no masses of metal interfere4 ,thus in tests of the person of a wounded man1 the presence of an iron truss1 or of metallic bed springs may invalidate all conclusions4 ,the same principle is carried out in an apparatus in which the parts are arranged like the members of a ,wheatstone bridge4 ,one pair of coils is used1 which react on each other as primary and secondary coils4 ,one of the coils is in series with a telephone in the member of the bridge corresponding to that containing the galvanometer of the ,wheatstone bridge4 ,the latter is more properly termed an induction bridge4 ,synonyms--,inductance ,bridge--,inductance ,balance--,induction ,bridge4 #bic ,,standard ,,electrical ,,dictionary4 ,hydro-electric4 adj4 7a7 ,a current produced by a voltaic couple or the couple itself is sometimes thus characterized or designated as a hydro-electric current or a hydro-electric couple4 ,it distinguishes them from thermo-electric4 7b7 ,armstrong's steam boiler electric machine 7see ,hydroelectric ,machine7 is also termed a hydro-electric machine4 ,hydro-electric ,machine4 ,an apparatus for generating high potential difference by the escape of steam through proper nozzles4 ,it consists of a boiler mounted on four glass legs or otherwise insulated4 ,an escape pipe terminates in a series of outlets so shaped as to impede the escape of the steam by forcing it out of the direct course4 ,these jets are lined with hard wood4 ,they are enclosed in or led through a box which is filled with cold water4 ,fig4 #aii4 ,,armstrong',s ,,hydro-,,electric ,,machine4 ,this is to partly condense the steam so as to get it into the vesicular state1 which is found essential to its action4 ,dry steam produces no excitation4 ,if the boiler is fired and the steam is permitted to escape under the above conditions the vesicles presumably1 or the steam is found to be electrified4 ,a collecting comb held against the jet becomes charged and charges any connected surface4 #bid ,,standard ,,electrical ,,dictionary4 ,the boiler in the above case is negatively and the escaping steam is positively charged4 ,by changing the material of the linings of the jets1 or by adding turpentine the sign of the electricity is reversed4 ,if the water contains acid or salts no electricity is produced4 ,the regular hydro-electric machine is due to ,sir ,william ,armstrong4 ,faraday obtained similar results with moist air currents4 ,hydrogen4 ,an element existing under all except the most extreme artificial conditions of pressure and cold as a gas4 ,it is the lightest of known substances4 ,atomic weight1 #a2 molecular weight1 #b2 equivalent1 #a2 valency1 #a2 specific gravity1 4#jfia-4jfie4 7,dumas ,boussingault47 ,it is a dielectric of about the same resistance as air4 ,its specific inductive capacity at atmospheric pressure is3 4#iiig 7,baltzman7 4#iiih 7,ayrton7 ,electro-chemical equivalent1 4#jaje milligram4 ,the above is usually taken as correct4 ,other values are as follows3 4#jajeba 7,kohllrausch7 4#jajdae 7,mascart7 ,the electro-chemical equivalent of any element is obtained by multiplying its equivalent by the electro-chemical equivalent of hydrogen4 ,the value 4#jaje has been used throughout this book4 ,hygrometer4 ,an instrument for determining the moisture in the air4 ,one form consists of a pair of thermometers1 one of which has its bulb wrapped in cloth which is kept moist during the observation4 ,the evaporation is more or less rapid according to the dryness or moisture of the air1 and as the temperature varies with this evaporation the relative readings of the two thermometers give the basis for calculating the hygrometric state of the air4 ,another form determines the temperature at which dew is deposited on a silver surface1 whence the calculations are made4 ,hysteresis1 ,magnetic4 ,a phenomenon of magnetization of iron4 ,it may be attributed to a sort of internal or molecular friction1 causing energy to be absorbed when iron is magnetized4 ,whenever therefore the polarity or direction of magnetization of a mass of iron is rapidly changed a considerable expenditure of energy is required4 ,it is attributed to the work done in bringing the molecules into the position of polarity4 #bie ,,standard ,,electrical ,,dictionary4 ,the electric energy lost by hysteresis may be reduced by vibrations or jarring imparted to the iron1 thus virtually substituting mechanical for electrical work4 ,on account of hysteresis the induced magnetization of a piece of iron or steel for fields of low intensity will depend on the manner in which the material has been already magnetized4 ,let the intensity of field increase1 the magnetization increasing also2 then lower the intensity2 the substance tends to and does retain some of its magnetism4 ,then on again strengthening the field it will have something to build on1 so that when it attains its former intensity the magnetization will exceed its former value4 ,for a moderate value of intensity of field the magnetization can have many values within certain limits4 ,synonym--,hysteresis--,hysteresis1 ,static--,magnetic ,friction4 ,hysteresis1 ,viscous4 ,the gradual increase or creeping up of magnetization when a magnetic force is applied with absolute steadiness to a piece of iron4 ,it may last for half an hour or more and amount to several per cent4 of the total magnetization4 ,it is a true magnetic lag4 ,i4 ,a symbol sometimes used to indicate current intensity4 ,thus ,ohm's law is often expressed ,i ,e_/,r1 meaning current intensity is equal to electro-motive force divided by resistance4 ,c is the more general symbol for current intensity4 ,ideoelectrics or ,idioelectrics4 ,bodies which become electric by friction4 ,this was the old definition1 the term originating with ,gilbert4 ,it was based on a misconception1 as insulation is all that is requisite for frictional electrification1 metals being thus electrified if held by insulating handles4 ,the term is virtually obsolete2 as far as it means anything it means insulating substances such as scaling wax1 sulphur1 or glass4 ,idle ,coils4 ,coils in a dynamo1 in which coils no electro-motive force is being generated4 ,this may occur when1 as a coil breaks connection with the commutator brush1 it enters a region void of lines of magnetic force1 or where the lines are tangential to the circle of the armature4 ,idiostatic ,method4 ,a method of using the absolute or attracted disc electrometer4 7,see ,electrometer1 ,absolute47 ,the suspended disc and guard ring are kept at the same potential1 which is that of one of the points whose potential difference is to be determined2 the lower fixed disc is connected to the other of the points whose potential difference is to be determined4 ,then we have the formula ,v d 99 ,square,root7 #h 99 ,,pi 99 ,f 7 _/ ,s in which d is the distance between the discs1 ,v is the difference of potential of the two points1 ,f the force of attraction between the discs in dynes1 and ,s the area of the suspended disc4 7,see ,heterostatic ,method47 #bif ,,standard ,,electrical ,,dictionary4 ,idle ,poles4 ,poles of wire sealed into ,crookes' tubes1 not used for the discharge connections1 but for experimental connections to test the effect of different excitation on the discharge4 ,idle ,wire4 ,in a dynamo the wire which plays no part in generating electro-motive force4 ,in a ,gramme ring the wire on the inside of the ring is idle wire4 ,igniter4 ,in arc lamps with fixed parallel carbons of the ,jablochkoff type 7see ,candle1 ,jablochkoff7 a strip of carbon connects the ends of the carbons in the unused candle4 ,this is necessary to start the current4 ,such strip is called an igniter4 ,it burns away in a very short time when an arc forms producing the light1 and lasts1 if all goes well1 until the candle burns down to its end4 ,without the igniter the current would not start and no arc would form4 ,i4 ,h4 ,p4 ,symbol for indicated horse-power4 ,illuminating ,power4 ,the relative light given by any source compared with a standard light1 and stated in terms of the same1 as a burner giving an illuminating power of sixteen candles4 ,for standards see ,candle1 ,carcel--,methven ,standard--,pentane ,standard4 ,illuminating ,power1 ,spherical4 ,the illuminating power of a lamp or source of light may vary in different directions1 as in the case of a gas burner or incandescent lamp4 ,the average illuminating power determined by photometric test or by calculation in all directions from the source of light is called the spherical illuminating power1 or if stated in candles is called the spherical candle power4 ,illumination1 ,unit of4 ,an absolute standard of light received by a surface4 ,preece proposed as such the light received from a standard candle 7see ,candle1 ,standard7 at a distance of #ab4g inches4 ,the object of selecting this distance was to make it equal to the ,carcel ,standard 7see ,carcel71 which is the light given by a ,carcel lamp at a distance of one meter4 ,from one-tenth to one-fiftieth this degree of illumination was found in gas-lighted streets by ,preece1 depending on the proximity of the gas lamps4 ,image1 ,electric4 ,an electrified point or system of points on one side of a surface which would produce on the other side of that surface the same electrical action which the actual electrification of that surface really does produce4 7,maxwell47 ,the method of investigating the distribution of electricity by electric images is due to ,sir ,william ,thomson4 ,the conception is purely a theoretical one1 and is of mathematical value and interest4 #big ,,standard ,,electrical ,,dictionary4 ,impedance4 ,the ratio of any impressed electro-motive force to the current which it produces in a conductor4 ,for steady currents it is only the resistance4 ,for variable currents it may include besides resistance inductance and permittance4 ,it is the sum of all factors opposing a current1 both ohmic and spurious resistances4 ,it is often determined and expressed as ohms4 ,synonym--,apparent ,resistance--,virtual ,resistance4 ,impedance1 ,oscillatory4 ,the counter-electro-motive force offered to an oscillatory discharge1 as that of a ,leyden jar4 ,it varies with the frequency of the discharge current4 ,synonym--,impulsive ,impedance4 ,impressed ,electro-motive ,force4 ,the electro-motive force expending itself in producing current induction in a neighboring circuit4 ,impulse4 7a7 ,an electro-magnetic impulse is the impulse produced upon the luminiferous ether by an oscillatory discharge or other varying type of current2 the impulse is supposed to be identical1 except as regards wave-length1 with a light wave4 7b7 ,an electro-motive impulse is the electro-motive force which rises so high as to produce an impulsive or oscillatory discharge1 such as that of a ,leyden jar4 ,incandescence1 ,electric4 ,the heating or a conductor to red1 or1 more etymologically1 to white heat by the passage of an electric current4 ,the practical conditions are a high intensity of current and a low degree of conductance of the conductor relatively speaking4 ,inclination ,map4 ,a map showing the locus of equal inclination or dips of the magnetic needle4 ,the map shows a series of lines1 each one of which follows the places at which the dip of the magnetic needle is identical4 ,the map changes from year to year4 7,see ,magnetic ,elements47 ,independence of ,currents in ,parallel ,circuits4 ,if a number of parallel circuits of comparatively high resistance are supplied by a single generator of comparatively low resistance1 the current passed through each one will be almost the same whether a single one or all are connected4 ,under the conditions named the currents are practically independent of each other4 ,transcriber's note3 ,the current in each parallel branch depends on the resistance_/impedance of that branch4 ,only if they all have the same impedance will the current be the same4 ,indicating ,bell4 ,an electric bell arranged to drop a shutter or disclose in some other way a designating number or character when rung4 #bih ,,standard ,,electrical ,,dictionary4 ,indicator4 7a7 ,an apparatus for indicating the condition of a distant element1 such as the water level in a reservoir1 the temperature of a drying room or cold storage room or any other datum4 ,they are of the most varied constructions4 7b7 ,the receiving instrument in a telegraph system is sometimes thus termed4 ,indicator1 ,circuit4 ,a galvanometer used to show when a circuit is active1 and to give an approximate measurement of its strength4 ,it is a less accurate and delicate form of instrument than the laboratory appliance4 ,inductance4 ,the property of a circuit in virtue of which it exercises induction and develops lines of force4 ,it is defined variously4 ,as clear and satisfactory a definition as any is the following1 due to ,sumpner and ,fleming3 ,inductance is the ratio between the total induction through a circuit to the current producing it4 ,thus taking a simple helix of five turns carrying a current of two units1 and assuming that #a1jjj lines of force passed through the central turn1 of which owing to leakage only #ijj thread the next adjacent on each side1 and again only #hjj through the end turns1 there would be #hjj #ijj #ajjj #ijj #hjj1 or #d1djj linkages of lines with the wire1 and this being with #b units of current1 there would be #b1bjj linkages with unit current1 and consequently the self-inductance of the helix would be #b1bjj centimetres4 7,kennelly47 ,inductance1 as regards its dimensions is usually reduced to a length1 hence the last word of the preceding quotation4 ,the practical unit of inductance is termed the henry1 from ,prof4 ,joseph ,henry2 the secohm1 or the quad or quadrant4 ,the latter alludes to the quadrant of the earth1 the value in length of the unit in question4 ,transcriber's note3 7,l 7di_/dt7 ,v74 ,a current changing at the rate of one ampere per second through a one henry inductance produces one volt4 ,a sinusoidal current produces a voltage #ij degrees ahead of the current1 a cosine 7the derivative of sine is cosine74 ,one volt across one henry causes the current to increase at one ampere per second4 ,induction1 ,coefficient of ,self4 ,the coefficient of self-induction of a circuit is the quantity of induction passing through it per unit current in it4 ,if a given circuit is carrying a varying current it is producing a varying quantity of magnetic induction through itself4 ,the quantity of induction through the circuit due to its current is generally proportional to its current4 ,the quantity for unit current is the coefficient of self-induction4 7,emtage47 ,induction1 ,cross4 ,the induction of magnetic lines of force in a dynamo armature core by the current passing around such armature4 ,these lines in a symmetrical two pole machine are at right angles to the lines of force which would normally extend across the space between the two magnet poles4 ,the joint magnetizing effect of the field and of the cross induction produces a distorted field between the poles 4 ,synonym--,cross-magnetizing ,effect4 #bii ,,standard ,,electrical ,,dictionary4 ,induction1 ,electro-magnetic4 ,the inter-reaction of electromagnetic lines of force with the production of currents thereby4 ,a current passing through a conductor establishes around it a field of force representing a series of circular lines of force concentric with the axis of the conductor and perpendicular thereto4 ,these lines of force have attributed to them1 as a representative of their polarity1 direction4 ,this is of course purely conventional4 ,if one is supposed to be looking at the end of a section of conductor1 assuming a current be passing through it towards the observer1 the lines of force will have a direction opposite to the motion of the hands of a watch4 ,the idea of direction may be referred to a magnet4 ,in it the lines of force are assumed to go from the north pole through the air or other surrounding dielectric to the south pole4 ,two parallel wires having currents passing through them in the same direction will attract each other4 ,this is because the oppositely directed segments of lines of force between the conductors destroy each other1 and the resultant of the two circles is an approximation to an ellipse4 ,as lines of force tend to be as short as possible the conductors tend to approach each other to make the ellipse become of as small area as possible1 in other words to become a circle4 ,if on the other hand the currents in the conductors are in opposite directions the segments of the lines of force between them will have similar directions1 will1 as it were1 crowd the intervening ether and the wires will be repelled4 ,fig4 #bjj4 ,,attraction ,,of ,,conductors ,,carrying ,,similar ,,currents4 ,by ,ampre's theory of magnetism1 7see ,magnetism1 ,ampre's ,theory of17 a magnet is assumed to be encircled by currents moving in the direction opposite to that of the hands of a watch as the observer faces the north pole4 ,a magnet near a wire tends to place the ,amprian currents parallel to the wire1 and so that the portion of the ,amprian currents nearest thereto will correspond in direction with the current in the wire4 #cjj ,,standard ,,electrical ,,dictionary4 ,this is the principle of the galvanometer4 ,a number of methods of memoria technica have been proposed to remember it by4 ,thus if we imagine a person swimming with the current and always facing the axis of the conductor1 a magnetic needle held where the person is supposed to be will have its north pole deflected to the right hand of the person4 ,fig4 #bja4 ,,repulsion ,,of ,,conductors ,,carrying ,,opposite ,,currents4 ,again if we think of a corkscrew1 which as it is turned screws itself along with the current1 the motion of the handle shows the direction of the lines of force and the direction in which the north pole of a needle is deflected4 ,this much is perhaps more properly electro-dynamics1 but is necessary as a basis for the expression of induction4 ,if a current is varied in intensity in one conductor it will induce a temporary current in another conductor1 part of which is parallel to the inducing current and which conductor is closed so as to form a circuit4 ,if the inducing current is decreased the induced current in the near and parallel portion of the other circuit will be of identical direction2 if increased the induced current will be of opposite direction4 ,this is easiest figured by thinking of the lines of force surrounding the inducing conductor4 ,if the current is decreased these can be imagined as receiving a twist or turn contrary to their normal direction1 as thereby establishing a turn or twist in the ether surrounding the other wire corresponding in direction with the direction of the original lines of force1 or what is the same thing1 opposite in direction to the original twist4 ,but we may assume that the establishment of such a disturbance causes a current1 which must be governed in direction with the requirements of the new lines of force4 ,the same reasoning applies to the opposite case4 #cja ,,standard ,,electrical ,,dictionary4 ,the general statement of a variable current acting on a neighboring circuit also applies to the approach or recession of an unvarying current1 and to the cutting of lines of force by a conductor at right angles thereto4 ,for it is evident that the case of a varying current is the case of a varying number of lines of force cutting or being cut by the neighboring conductor4 ,as lines of force always imply a current1 they always imply a direction of such current4 ,the cutting of any lines of force by a closed conductor always implies a change of position with reference to all portions of such conductor and to the current and consequently an induced current or currents in one or the other direction in the moving conductor4 ,as the inducing of a current represents energy abstracted from that of the inducing circuit1 the direction of the induced current is determined by 7,lenz's ,law7 the rule that the new current will increase already existing resistances or develop new ones to the disturbance of the inducing field4 ,in saying that a conductor cutting lines of force at right angles to itself has a current induced in it1 it must be understood that if not at right angles the right angle component of the direction of the wire acts in generating the current4 ,the case resolves itself into the number of lines of force cut at any angle by the moving wire4 ,the lines of force may be produced by a magnet1 permanent or electro4 ,this introduces no new element4 ,the magnet may be referred1 as regards direction of its lines of force1 to its encircling currents1 actual or ,amprian1 and the application of the laws just cited will cover all cases4 ,induction1 ,coefficient of ,mutual4 ,the coefficient of mutual induction of two circuits is the quantity of magnetic induction passing through either of them per unit current in the other4 7,emtage47 ,it is also defined as the work which must be done on either circuit1 against the action of unit current in each1 to take it away from its given position to an infinite distance from the other2 and also as the work which would be done by either circuit on the other in consequence of unit current in each1 as the other moves from an infinite distance to its given position with respect to the other conductor4 ,it depends on the form1 size1 and relative position of the two circuits2 and on the magnetic susceptibilities of neighboring substances4 ,the ether surrounding two circuits of intensity i' and i must possess energy1 expressible 7,maxwell7 as #a_/b ,l i#b ,m i i #a_/b ,n i#ab4 ,it can be shown that ,m i i#a in any given position of the two circuits is numerically equal 7#a7 to the mutual potential energy of the two circuits 7#b7 to the number of lines of induction1 which being due to ,a1 pass from ,a through ,b1 or equally being due to ,b1 pass from ,b through ,a1 and ,m is styled the coefficient of mutual induction4 7,daniell47 #cjb ,,standard ,,electrical ,,dictionary4 ,induction1 ,electrostatic4 ,an electrostatic charge has always an opposite and bound charge4 ,this may be so distributed as not to be distinguishable1 in which case the charge is termed1 incorrectly but conventionally1 a free charge4 ,but when a charge is produced an opposite and equal one always is formed1 which is the bound charge4 ,the region between the two charges and permeated by their lines of force1 often curving out so as to embrace a volume of cross-sectional area larger than the mean facing area of the excited surfaces1 is an electrostatic field of force4 ,the establishing of an electrostatic field1 and the production of a bound charge are electrostatic induction4 ,an insulated conductor brought into such a field suffers a redistribution of its electricity1 or undergoes electrostatic induction4 ,the parts nearest respectively1 the two loci of the original and the bound charges1 are excited oppositely to such charges4 ,the conductor presents two new bound charges1 one referred to the original charge1 the other to the first bound charge4 ,induction1 ,horizontal4 ,in an iron or steel ship the induction exercised upon the compass needle by the horizontal members of the structure1 such as deck-beams1 when they are polarized by the earth's magnetic induction4 ,this induction disappears four times in swinging a ship through a circle2 deviation due to it is termed quadrantal deviation4 7,see ,deviation1 ,quadrantal47 ,induction1 ,lateral4 ,a term formerly used to express the phenomenon of the alternative discharge of a ,leyden jar or other oscillatory discharge of electricity4 7,see ,discharge1 ,alternative47 ,induction1 ,magnetic4 ,the magnetization of iron or other paramagnetic substance by a magnetic field4 ,on account of its permeability or multiplying power for lines of force1 a paramagnetic body always concentrates lines of force in itself if placed in a magnetic field1 and hence becomes for the time being a magnet1 or is said to be polarized4 ,as the tendency of lines of force is to follow the most permeable path1 a paramagnetic bar places itself lengthwise or parallel with the prevailing direction of the lines of force so as to carry them as far on their way as possible4 ,every other position of the bar is one of unstable equilibrium or of no equilibrium4 ,the end of the bar where the lines of force enter 7see ,lines of ,force7 is a south pole and is attracted towards the north pole of the magnet4 ,the production of magnetic poles under these conditions in the bar is shown by throwing iron filings upon it4 ,they adhere to both ends but not to the middle4 ,induction1 ,mutual1 ,electro-magnetic4 ,the induction due to two electric currents reacting on each other4 #cjc ,,standard ,,electrical ,,dictionary4 ,induction1 ,mutual1 ,electrostatic4 ,a charged body always induces a charge upon any other body near it2 and the same charge in the second body will induce the other charge in the first body if the latter is unexcited4 ,in other words the second body's induction from the first is the measure of the charge the second would require to induce in the first its own 7the second's7 induced charge4 ,this is the law of mutual electrostatic induction4 ,induction1 ,open ,circuit4 ,inductive effects produced in open circuits4 ,by oscillatory discharges a discharge can be produced across a break in a circuit otherwise complete4 ,the requirements for its production involve a correspondence or relation of its dimensions to the inducing discharge4 ,the whole is analogous to the phenomena of sound resonators and sympathetic vibrations4 ,synonym--,oscillatory induction4 ,induction1 ,self-4 7a7 ,a phenomenon of electric currents analogous to the inertia of matter4 ,just as water which fills a pipe would resist a sudden change in its rate of motion1 whether to start from rest1 to cease or decrease its motion1 so an electric current requires an appreciable time to start and stop4 ,it is produced most strongly in a coiled conductor1 especially if a core of iron is contained within it4 ,as in the case of two parallel wires1 one bearing currents which vary1 momentary currents are induced in the other wire1 so in a single conductor a species of inertia is found which retards and prolongs the current4 ,if a single conductor is twisted into a helix or corresponding shape1 its separate turns react one on the other in accordance with the general principles of electromagnetic induction4 7,see ,induction1 ,electro-magnetic47 ,thus when a current is suddenly formed the coils acting upon each other retard for an instant its passage1 producing the effect of a reverse induced current or extra current opposing the principal current4 ,of course no extra current is perceptible1 but only the diminution4 ,when the current is passing regularly and the current is broken1 the corresponding action prolongs the current or rather intensifies it for an instant1 producing the true extra current4 ,this is current self-induction4 ,transcriber's note3 ,see inductance4 ,synonyms--,electric ,inertia--,electro-dynamic ,capacity4 7b7 ,a permanent magnet is said to tend to repel its own magnetism1 and thus to weaken itself2 the tendency is due to magnetic self-induction4 ,induction ,sheath4 ,in the brush dynamo a thin sheet of copper surrounding the magnet cores with edges soldered together4 ,the winding is outside of it4 ,its object is to absorb extra currents set up by variations in magnetic intensity in the cores4 ,these currents otherwise would circulate in the cores4 #cjd ,,standard ,,electrical ,,dictionary4 ,induction1 ,unit of ,self-4 ,the unit of self-induction is the same as that of induction in general4 ,it is the henry1 q4 v4 ,induction1 ,unipolar4 ,induction produced in a conductor which continuously cuts the lines of force issuing from one pole of a magnet4 ,as the lines of force are always cut in the same sense a continuous and constant direction current is produced4 ,induction1 ,vertical4 ,in an iron or steel ship the induction or attraction exercised in the compass by vertical elements of the structure4 ,such vertical masses of iron in the northern hemisphere would have their upper ends polarized as south poles1 and would affect the magnet as soon as the vessel swung out of the magnetic meridian4 ,thus this induction disappears twice in swinging a ship through a complete circle2 deviation due to it is termed semi-circular deviation4 7,see ,deviation1 ,semi-circular47 ,fig4 #bjb4 ,,inductor ,,dynamo4 ,inductophone4 ,a method of train telegraphy4 ,the train carries a circuit including a coil1 and messages are picked up by it from coils along the line into which an alternating current is passed4 ,a telephone is used as a receiver in place of a sounder or relay4 ,the invention1 never practically used1 is due to ,willoughby ,smith4 #cje ,,standard ,,electrical ,,dictionary4 ,inductor4 7a7 ,in a current generator a mass of iron1 generally laminated1 which is moved past a magnet pole to increase the number of lines of force issuing therefrom4 ,it is used in inductor dynamos4 7,see ,dynamo ,inductor47 ,in the cut ,fig4 #bjb1 of an inductor dynamo i1 i1 are the laminated inductors4 7b7 ,in influence machines the paper or tinfoil armatures on which the electrification is induced4 ,inertia4 ,a force in virtue of which every body persists in its state of motion or rest except so far as it is acted on by some force4 ,inertia1 ,electro-magnetic4 ,this term is sometimes applied to the phenomena of self-induction1 or rather to the cause of these phenomena4 ,infinity ,plug4 ,a plug in a resistance box1 which on being pulled out of its seat opens the circuit or makes it of infinite resistance4 ,the plug seats itself between two brass plates which are not connected with each other in any way4 ,the other plates are connected by resistance coils of varying resistance4 ,influence1 ,electric4 ,electric induction1 which may be either electrostatic1 current1 or electro-magnetic4 ,insolation1 ,electric4 ,exposure to powerful arc-light produces effects resembling those of sun-stroke4 ,the above term or the term electric sun-stroke has been applied to them4 ,transcriber's note3 ,operators of arc welders are prone to skin cancer from ultra violet rays if not properly protected4 ,installation4 ,the entire apparatus1 buildings and appurtenances of a technical or manufacturing establishment4 ,an electric light installation1 for instance1 would include the generating plant1 any special buildings1 the mains and lamps4 ,insulating ,stool4 ,a support for a person1 used in experiments with static generators4 ,it has ordinarily a wooden top and glass legs4 ,it separates one standing on it from the earth and enables his surface to receive an electrostatic charge4 ,this tends to make his hair stand on end1 and anyone on the floor who touches him will receive a shock4 ,insulating ,tape4 ,prepared tape used in covering the ends of wire where stripped for making joints4 ,after the stripped ends of two pieces are twisted together1 and if necessary soldered and carefully cleaned of soldering fluid1 they may be insulated by being wound with insulating tape4 ,the tape is variously prepared4 ,it may be common cotton or other tape saturated with any insulating compound1 or may be a strip of gutta percha or of some flexible cement-like composition4 #cjf ,,standard ,,electrical ,,dictionary4 ,insulating ,varnish4 ,varnish used to coat the surface of glass electrical apparatus1 to prevent the deposition of hygrometric moisture1 and also in the construction of magnetizing and induction coils and the like4 ,shellac dissolved in alcohol is much used4 ,gum copal dissolved in ether is another4 ,a solution of sealing wax in alcohol is also used4 ,if applied in quantities these may need baking to bring about the last drying4 7,see ,shellac ,varnish47 ,insulator4 7a7 ,any insulating substance4 7b7 ,a telegraph or line insulator for telegraph wires4 7,see ,insulator1 ,line or ,telegraph47 ,synonyms--,dielectric--,non-conductor4 ,insulator ,cap4 ,a covering or hood1 generally of iron1 placed over an insulator to protect it from injury by fracture with stones or missiles4 ,insulator1 ,fluid4 7a7 ,for very high potentials1 as in induction coils or alternating circuits1 fluid insulators1 such as petroleum or resin oil1 have been used4 ,their principal merit is that if a discharge does take place through them the opening at once closes1 so that they are self-healing4 7b7 ,also a form of telegraph or line insulator in which the lower rim is turned up and inwards1 so as to form an annular cup which is filled with oil4 ,insulator1 ,line or ,telegraph4 ,a support often in the shape of a collar or cap1 for a telegraph or other wire1 made of insulating material4 ,glass is generally used in the ,united ,states1 porcelain is adopted for special cases2 pottery or stone ware insulators have been used a great deal in other countries4 ,sometimes the insulator is an iron hook set into a glass screw1 which is inserted into a hole in a telegraph bracket4 ,sometimes a hook is caused to depend from the interior of an inverted cup and the space between the shank of the hook and cup is filled with paraffine run in while melted4 ,insulators are tested by measuring their resistance while immersed in a vessel of water4 ,intensity4 ,strength4 ,the intensity of a current or its amperage or strength2 the intensity or strength of a magnetic field or its magnetic density2 the intensity or strength of a light are examples of its use4 ,in the case of dynamic electricity it must be distinguished from tension4 ,the latter corresponds to potential difference or voltage and is not an attribute of current2 intensity has no reference to potential and is a characteristic of current4 ,intensity of a ,magnetic ,field4 ,the intensity of a magnetic field at any point is measured by the force with which it acts on a unit magnet pole placed at that point4 ,hence unit intensity of field is that intensity of field which acts on a unit pole with a force of one dyne4 7,s4 ,p4 ,thomson47 7,see ,magnetic ,lines of ,force47 #cjg ,,standard ,,electrical ,,dictionary4 ,intercrossing4 ,crossing a pair of conductors of a metallic circuit from side to side to avoid induction from outside sources4 ,intermittent4 ,acting at intervals1 as an intermittent contact1 earth1 or grounding of a telegraph wire4 ,interpolar ,conductor4 ,a conductor connecting the two poles of a battery or current generator2 the external circuit in a galvanic circuit4 ,interpolation4 ,a process used in getting a closer approximation to the truth from two varying observations1 as of a galvanometer4 ,the process varies for different cases1 but amounts to determining an average or deducing a proportional reading from the discrepant observed ones4 ,interrupter4 ,a circuit breaker4 ,it may be operated by hand or be automatic4 7,see ,circuit ,breaker--,circuit ,breaker1 ,automatic--and others47 ,interrupter1 ,electro-magnetic1 for a ,tuning ,fork4 ,an apparatus for interrupting a current which passes through an electromagnet near and facing one of the limbs of a tuning fork4 ,the circuit is made and broken by the vibrations of another tuning fork through which the current passes4 ,the second one is thus made to vibrate1 although it may be very far off and may not be in exact unison with the first4 ,the first tuning fork has a contact point on one of its limbs1 to close the circuit2 it may be one which dips into a mercury cup4 ,intrapolar ,region4 ,a term in medical electricity1 denoting the part of a nerve through which a current is passing4 ,ions4 ,the products of decomposition produced in any given electrolysis are termed ions1 the one which appears at the anode or negative electrode is the anion4 ,the electrode connected to the carbon or copper plate of a wet battery is an anode4 ,thus in the electrolysis of water oxygen is the anion and hydrogen is termed the kation4 ,in this case both anion and kation are elements4 ,in the decomposition of copper sulphate the anion is properly speaking sulphion 7,s ,o#d71 a radical1 and the kation is copper1 an element4 ,electro-negative elements or radicals are anions1 such as oxygen1 sulphion1 etc41 while electro-positive ones are kations1 such as potassium4 ,again one substance may be an anion referred to one below it and a kation referred to one above it1 in the electro-chemical series1 q4 v4 ,anion means the ion which goes to the anode or positive electrode2 kation1 the ion which goes to the kathode or negative electrode4 ,transcriber's note3 ,an ion is an atom or molecule that has lost or gained one or more valence electrons1 giving it a positive or negative electrical charge4 ,a negatively charged ion1 with more electrons than protons in its nuclei1 is an anion4 ,a positively charged ion1 with fewer electrons than protons1 is a cation4 ,the electron was discovered five years after this publication4 #cjh ,,standard ,,electrical ,,dictionary4 ,iron4 ,a metal2 one of the elements2 symbol1 ,fe2 atomic weight1 #ef2 equivalent1 #bh and #ad1 2 valency1 #d and #b4 ,it is a conductor of electricity4 ,the following data are at #j ,c4 #cb ,f41 with annealed metal4 ,specific ,resistance1 #i4gaf microhms4 ,relative ,resistance4 #f4dfj ,resistance of a wire1 7a7 #a foot long weighing #a grain1 #a4jhe ohms4 7b7 #a foot long #a_/ajjj inch thick1 #eh4de 7c7 #a meter long weighing #a gram1 4#gegj 7d7 #a meter long1 #a millimeter thick1 4#abcg ,percentage increase in resistance per degree ,c4 7#a4h ,f47 at about #bj ,c4 7#fh;,f471 about #j4e per cent4 ,resistance of a #a inch cube1 #c4hbe microhms4 ,electro-chemical equivalent 7,hydrogen 4#jaje71 4#adg and 4#bid ,iron1 ,electrolytic4 ,iron deposited by electrolytic action4 ,various baths are employed for its formation4 7,see ,steeling47 ,it has very low coercive power1 only seven to ten times that of nickel4 ,ironwork ,fault of a ,dynamo4 ,a short circuiting of a dynamo by1 or any connection of its coils with1 the iron magnet cores or other iron parts4 ,isochronism4 ,equality of periodic time2 as of the times of successive beats of a tuning fork1 or of the times of oscillations of a pendulum4 ,isoclinic ,lines4 ,the lines denoting the locus of sets of equal dips or inclinations of the magnetic needle upon the earth's surface1 the magnetic parallels1 q4 v4 ,these lines are very irregular4 7,see ,magnetic ,elements47 ,isoclinic ,map4 ,a map showing the position of isoclinic lines4 ,isodynamic ,lines4 ,lines marking the locus of places of equal magnetic intensity on the earth's surface4 7,see ,magnetic ,elements1 ,poles of ,intensity47 ,isodynamic ,map4 ,a map showing the position of isodynamic lines4 7,see ,poles of ,intensity47 ,isogonic ,lines4 ,lines on a map marking the locus of or connecting those points where the declination or variation of the magnetic needle is the same4 7,see ,magnetic ,elements--,declination of ,magnetic ,needle47 ,synonyms--,isogonal ,lines--,halleyan ,lines4 #cji ,,standard ,,electrical ,,dictionary4 ,isogonic ,map4 ,a map showing the isogonic lines4 ,on such a map each line is characterized and marked with the degrees and direction of variation of the compass upon itself4 ,synonym--,declination ,map4 ,isolated ,plant1 ,distribution or ,supply4 ,the system of supplying electric energy by independent generating systems1 dynamo or battery1 for each house1 factory or other place1 as contra-distinguished from ,central ,station ,distribution or ,supply4 ,isotropic4 7,greek1 equal in manner47 ,having equal properties in all directions2 the reverse of anisotropic1 q4 v4 ,thus a homogeneous mass of copper or silver has the same specific resistance in all directions and is an isotropic conductor4 ,glass has the same specific inductive capacity in all directions and is an isotropic medium or dielectric4 ,the same applies to magnetism4 ,iron is an isotropic paramagnetic substance4 7,see ,anisotropic47 ,the term applies to other branches of physics also4 ,i4 ,w4 ,g4 ,contraction for ,indian ,wire ,gauge--the gauge adopted in ,british ,india4 ,j4 ,symbol for the unit joule1 the unit of electric energy4 ,jacobi's ,law4 ,a law of electric motors4 ,it states that the maximum work of a motor is performed when the counter-electromotive force is equal to one-half the electro-motive force expended on the motor4 ,jewelry4 ,small incandescent lamps are sometimes mounted as articles of jewelry in scarf-pins or in the hair4 ,they may be supplied with current from storage or from portable batteries carried on the person4 ,joint1 ,american ,twist4 ,a joint for connecting telegraph wires1 especially aerial lines4 ,its construction is shown in the cut4 ,the end of each wire is closely wound around the straight portion of the other wire for a few turns4 ,fig4 #bjc4 ,,american ,,twist ,,joint4 #caj ,,standard ,,electrical ,,dictionary4 ,joint1 ,britannia4 ,a joint for uniting the ends of telegraph and electric wires4 ,the ends of the wires are scraped clean and laid alongside each other for two inches1 the extreme ends being bent up at about right angles to the wire4 ,a thin wire is wound four or five times around one of the wires1 back of the joint1 the winding is then continued over the lapped portion1 and a few more turns are taken around the other single wire4 ,the whole is then soldered4 ,fig4 #bjd4 ,,britannia ,,joint4 ,joint1 ,butt4 ,a joint in belting or in wire in which the ends to be joined are cut off square across1 placed in contact and secured4 ,it ensures even running when used in belting4 ,any irregularity in thickness of a belt affects the speed of the driven pulley4 ,as dynamos are generally driven by belts1 and it is important to drive them at an even speed to prevent variations in the electro-motive force1 butt joints should be used on belting for them1 unless a very perfect lap joint is made1 which does not affect either the thickness or the stiffness of the belt4 ,when a butt joint is used in wire a sleeve may be used to receive the abutting ends1 which may be secured therein by soldering4 ,this species of joint has been used on lightning rods and may more properly be termed a sleeve joint4 ,joint1 ,lap4 7a7 ,in belting a joint in which the ends are overlapped1 and riveted or otherwise secured in place4 ,if made without reducing the thickness of the ends it is a bad joint for electrical work1 as it prevents even running of machinery to which it is applied4 ,hence dynamo belts should be joined by butt joints1 or if by lap joints the ends should be shaved off so that when joined and riveted1 there will be no variation in the thickness of the belt4 7b7 ,in wire lap joints are made by overlapping the ends of the wire and soldering or otherwise securing4 ,the ,britannia joint 7see ,joint1 ,britannia17 may be considered a lap-joint4 ,joint1 ,marriage4 ,a joint for stranded conductors used for ,galende's cables4 ,it is made somewhat like a sailor's long splice4 ,each one of the strands is wound separately into the place whence the opposite strand is unwound and the ends are cut off so as to abutt4 ,in this way all are smoothly laid in place and soldering is next applied4 ,fig4 #bje4 ,,marriage ,,joint4 #caa ,,standard ,,electrical ,,dictionary4 ,joint1 ,sleeve4 ,a joint in electric conductors1 in which the ends of the wires are inserted into and secured in a metallic sleeve or tube1 whose internal diameter is just sufficient to admit them4 ,joint1 ,splayed4 ,the method of joining the ends of stranded conductors4 ,the insulating covering is removed1 the wires are opened out1 and the center wire1 heart or core of the cable is cut off short4 ,the two ends are brought together1 the opened out wires are interlaced or crotched like the fingers of the two hands1 and the ends are wound around the body of the cable in opposite directions4 ,the joint is trimmed and well soldered4 ,tinned wire with rosin flux for the soldering is to be recommended4 ,insulating material is finally applied by hand1 with heat if necessary4 ,joints in ,belts4 ,belt-joints for electric plants where the belts drive dynamos should be made with special care4 ,the least inequality affects the electro-motive force4 ,butt joints are1 generally speaking1 the best1 where the ends of the belt are placed in contact and laced4 ,lap-joints are made by overlapping the belt1 and unless the belt is carefully tapered so as to preserve uniform strength1 the speed of the dynamo will vary and also the electromotive force4 ,joulad4 ,a name proposed to be substituted for joule1 q4 v4 ,it has not been adopted4 ,joule4 ,this term has been applied to several units4 7a7 ,the practical ,c4 ,g4 ,s4 unit of electric energy and work--the volt-coulomb4 ,it is equal to #a;,e#g ergs--#j4gcgcd foot pound4--4#jjacd horse power seconds4 ,a volt-ampere represents one joule per second4 7b7 ,it has also been used as the name of the gram-degree ,c4 thermal unit--the small calorie4 ,synonym--,joulad4 ,joule ,effect4 ,the heating effect of a current passing through a conductor4 ,it varies with the product of the resistance by the square of the current1 or with 7,c#b799,r4 ,joule's ,equivalent4 ,the mechanical equivalent of heat1 which if stated in foot-pounds per pound-degree ,f4 units1 is #ggb 7#ggb4ee74 7,see ,equivalents47 ,junction ,box4 ,in underground distribution systems1 an iron casing or box in which the feeders and mains are joined1 and where other junctions are made4 ,synonym--,fishing ,box4 ,k4 ,the symbol for electrostatic capacity4 ,kaolin4 ,a product of decomposition of feldspar1 consisting approximately of silica1 #de1 alumina1 #dj1 water1 #ae4 ,it was used in electric candles of the ,jablochkoff type as a constituent of the insulating layer or colombin4 ,later it was abandoned for another substance1 as it was found that it melted and acted as a conductor4 #cab ,,standard ,,electrical ,,dictionary4 ,kapp ,line of ,force4 ,a line of force proposed by ,kapp4 ,it is equal to #f1jjj ,c4 ,g4 ,s4 lines of force1 and the unit of area is the square inch4 ,unfortunately it has been adopted by many manufacturers1 but its use should be discouraged1 as it is a departure from the uniform system of units4 ,one ,kapp line per square inch #icj ,c4 ,g4 ,s4 lines per square centimeter4 ,kathelectrotonus4 ,a term used in medical electricity or electro-therapeutics to indicate the increased functional activity induced in a nerve by the proximity of the kathode of an active circuit which is completed through the nerve4 ,the converse of anelectrotonus4 ,kathode4 ,the terminal of an electric circuit whence an electrolyzing current passes from a solution4 ,it is the terminal connected to the zinc plate of a primary battery4 ,kathodic ,closure ,contraction4 ,a term in electro-therapeutics2 the contractions near where the kathode of an active circuit is applied to the body1 which are observed at the instant when the circuit is closed4 ,kathodic ,duration ,contraction4 ,a term in electro-therapeutics2 the contraction near where the kathode of an active circuit is applied to the body for a period of time4 ,k4 ,c4 ,c4 ,abbreviation for ,kathodic ,closure ,contraction1 q4 v4 ,k4 ,d4 ,c4 ,abbreviation for ,kathodic ,duration ,contraction1 q4 v4 ,keeper4 ,a bar of soft iron used to connect the opposite poles of a horseshoe magnet or the opposite poles of two bar magnets placed side by side4 ,it is designed to prevent loss of magnetism4 ,the armature of a horseshoe magnet is generally used as its keeper4 ,for bar magnets a keeper is used for each end1 the magnets being laid side by side1 with their poles in opposite direction but not touching1 and a keeper laid across at each end connecting the opposite poles4 ,kerr ,effect4 ,the effect of an electrostatic field upon polarized light traversing a dielectric contained within the field4 7,see ,electrostatic ,refraction47 ,kerr's ,experiment4 ,polarized light reflected from the polished face of a magnet pole has its plane of polarization rotated2 when it is reflected from the north pole the rotation is from left to right4 #cac ,,standard ,,electrical ,,dictionary4 ,key4 ,a switch adapted for making and breaking contact easily when worked by hand1 as a ,morse telegraph key4 ,key ,board4 ,a board or tablet on which keys or switches are mounted4 ,key-board4 7a7 ,a switch board1 q4 v4 7b7 ,a set of lettered keys similar to those of a typewriter employed in some telegraph instruments4 ,as each key is depressed it produces the contact or break requisite for the sending of the signal corresponding to the letter marked upon the key4 ,the signal in printing telegraphs1 on which such key-boards are used1 is the reprinting of the letter at the distant end of the line4 ,key1 ,bridge4 ,a key for use with a ,wheatstone ,bridge1 q4v4 ,it is desirable to first send a current through the four arms of the bridge in using it for testing resistances and then through the galvanometer1 because it takes a definite time for the current to reach its full strength4 ,this is especially the case if the element being measured has high static capacity1 as a long ocean cable4 ,if the galvanometer connections were completed simultaneously with the bridge connections a momentary swing would be produced even if the arms bore the proper relation to each other4 ,this would cause delay in the testing4 ,a bridge key avoids this by first connecting the battery circuit through the arms of the bridge1 and then as it is still further depressed the galvanometer circuit is completed4 #cad ,,standard ,,electrical ,,dictionary4 ,fig4 #bjf4 ,,charge ,,and ,,discharge ,,key ,key1 ,charge and ,discharge4 ,a key for use in observing the discharge of a condenser immediately after removing the battery4 ,in one typical form it has two contacts1 one below and one above1 and being a spring in itself is pressed up against the upper one4 ,connections are so made that when in its upper position it brings the two coatings of the condenser in circuit with the galvanometer4 ,when depressed it does the same for a battery4 ,in use it is depressed and suddenly released when the galvanometer receives the full charge1 before there has been time for leakage4 ,this is one method of connection illustrating its principle4 ,in the cut ,l is the spring-key proper4 ,s#b1 is the upper contact screw against which the spring normally presses4 ,in this position the galvanometer ,g is in circuit with the opposite coatings of the condenser ,c4 ,on depressing the contact ,s#b1 is broken and ,s#a1 is made4 ,this brings the battery ,b in circuit with the condenser coatings4 ,on releasing the key it springs up and the galvanometer receives the effect of the charge of the condenser as derived from the battery4 ,key1 ,double ,contact4 ,a key arranged to close two distinct circuits1 holding the first closed until the second is completed4 ,it is used for ,wheatstone bridge work4 ,key1 ,double ,tapper4 ,a telegraph key giving contacts alternately for currents in opposite directions1 used in needle telegraphy4 ,key1 ,increment4 ,a key for use in duplex and quadruplex telegraphy4 ,its action is to increase the line current1 not merely to suddenly turn current into it4 #cae ,,standard ,,electrical ,,dictionary4 ,fig4 #bjg4 ,,kempe',s ,,discharge ,,key4 ,key1 ,kempe's ,discharge4 ,a key giving a charging1 discharging and insulating connection1 for static condenser work4 ,referring to the cut l is a lever or spring with upper discharging contact s1 and lower charging contact s'4 ,in use it is pressed down by the insulating handle or finger piece ,c1 until caught by the hook attached to the key ,i4 ,this hook is lower down than that on the key ,d1 and holds it in contact with the charging contact piece ,s'4 ,on pressing the key ,i1 marked or designated ,insulate1 it springs up1 breaks contact at ,s'1 and catching against the hook on ,d1 which key is designated ,discharge1 remains insulated from both contacts2 next on pressing ,d it is released and springs up and closes the discharge contact ,s4 ,it is a form of charge and discharge key4 7,see ,key1 ,charge and ,discharge47 ,key1 ,magneto-electric4 ,a telegraph key whose movements operate what is virtually a small magneto-generator1 so as to produce currents of alternating direction1 one impulse for each motion of the key4 ,it is employed for telegraphing without a line battery1 a polarized relay being used4 ,in one very simple form a key is mounted on a base with a permanent magnet and connected to the armature1 so that when the key is pressed downwards it draws the armature away from the poles of the magnet4 ,if the magnet or its armature is wound with insulated wire this action of the key will cause instantaneous currents to go through a circuit connected to the magnet or armature coils4 ,fig4 #bjh4 ,,siemens' ,,magneto-,,electric ,,key4 ,in ,siemens ,halske's key an ,h armature ,e is pivoted between the poles ,n ,s1 of a powerful compound horseshoe magnet1 ,g ,g4 ,it is wound with fine wire and a key handle ,h is provided for working it4 ,in its normal position the handle is drawn upward1 and the end ,s ,s of the armature core is in contact with the south pole ,s of the permanent magnet1 and the end ,d ,d with the north pole4 ,this establishes the polarity of the armature4 ,on depressing the key the contacts are broken and in their place the end ,d ,d comes in contact with the south pole and the end ,s ,s with the north pole4 ,this suddenly reverses the polarity of the armature and sends a momentary current through the armature coil which is in circuit with the line4 ,the cut only shows the principle of the key1 whose construction is quite complicated4 #caf ,,standard ,,electrical ,,dictionary4 ,key1 ,make and ,break4 ,an ordinary electric key1 usually making a contact when depressed1 and rising by spring action when released1 and in its rise breaking the contact4 ,fig4 #bji4 ,,plug ,,key ,key1 ,plug4 ,an appliance for closing a circuit4 ,two brass blocks are connected to the terminals1 but are disconnected from each other4 ,a brass plug slightly coned or with its end split so as to give it spring action is thrust between the blocks to complete the circuit4 ,it is used in ,resistance coils and elsewhere4 7,see ,coil1 ,resistance47 ,grooves are formed in the blocks to receive the plug4 ,key1 ,reversing4 7a7 ,a double key1 arranged so that by depressing one key a current flows in one direction1 and by depressing the other a current flows in the opposite direction4 ,it is used in connection with a galvanometer in experimental1 testing or measuring operations4 7b7 ,a key effecting the same result used in quadruplex telegraphy4 ,key1 ,sliding-,contact4 ,a name given to the key used for making instantaneous contacts with the metre wire of a metre bridge1 q4 v4 ,the name is not strictly correct1 because it is important that there should be no sliding contact made1 as it would wear out the wire and make it of uneven resistance4 ,it is a key which slides along over the wire and which1 when depressed1 presses a platinum tipped knife edge upon the wire4 ,on being released from pressure the key handle springs up and takes the knife edge off the wire4 ,this removal is essential to avoid wearing the wire1 whose resistance per unit of length must be absolutely uniform4 ,key1 ,telegraph4 ,the key used in telegraphy for sending currents as desired over the line4 ,it consists of a pivoted lever with finger piece1 which lever when depressed makes contact between a contact point on its end and a stationary contact point on the base4 ,this closes the circuit through the line4 ,when released it springs up and opens the line circuit4 ,kilo4 ,a prefix to the names of units2 it indicates one thousand times1 as kilogram1 one thousand grams4 ,a few such units are given below4 ,kilodyne4 ,a compound unit2 one thousand dynes4 7,see ,dyne47 ,kilogram4 ,a compound unit2 one thousand grams2 #b4bjdf pounds avds4 #cag ,,standard ,,electrical ,,dictionary4 ,kilojoule4 ,a compound unit2 one thousand joules1 q4 v4 ,kilometer4 ,a compound unit2 one thousand meters2 #cbhj4hii feet2 #j4fbachb statute miles4 7,see ,meter47 ,kilowatt4 ,a compound unit2 one thousand watts1 q4 v4 ,kine4 ,an absolute or ,c4 ,g4 ,s4 unit of velocity or rate of motion2 one centimeter per second2 proposed by the ,british ,association4 ,kirchoff's ,laws4 ,these relate to divided circuits4 ,i4 ,when a steady current branches1 the quantity of electricity arriving by the single wire is equal to the quantity leaving the junction by the branches4 ,the algebraical sum of the intensities of the currents passing towards 7or passing from7 the junction is equal to zero2 ,summation7,c7 #j 7,daniell47 ,in the last sentence currents flowing towards the point are considered of one sign and those flowing away from it of the other4 ,,ii4 ,in a metallic circuit comprising within it a source of permanent difference of potential1 ,e1 the products of the intensity of the current within each part of the circuit into the corresponding resistance are1 if the elements of current be all taken in cyclical order together1 equal to ,e2 ,summation7,c 99 r7 ,e4 ,in a metallic circuit in which there is no source of permanent difference of potential ,e #j1 and ,summation7,c 99 r7 #j4 ,this law applies to each several mesh of a wire network as well as to a single metallic loop1 and it holds good even when an extraneous current is passed through the loop4 7,daniell47 ,in this statement of the two laws ,e stands for electro-motive force1 ,c for current intensity2 and r for resistance of a single member of the circuit4 ,transcriber's note3 ,these laws may be restated as3 ,at any point in an steady-state electrical circuit1 the directed sum of currents flowing towards that point is zero4 ,the directed sum of the electrical potential differences around any closed circuit is zero4 ,knife-edge ,suspension4 ,the suspension of an object on a sharp edge of steel or agate4 ,the knife edge should abut against a plane4 ,the knife edge is generally carried by the poised object4 ,its edge then faces downward and on the support one or more plane or approximately plane surfaces are provided on which it rests4 ,in the ordinary balance this suspension can be seen4 ,it is sometimes used in the dipping needle4 ,it is applied in cases where vertical oscillations are to be provided for4 ,knot4 ,the geographical mile2 a term derived from the knots on the log line1 used by navigators4 ,it is equal to #f1jhg feet4 ,synonyms--,nautical ,mile--,geographical ,mile4 ,transcriber's note3 ,a knot is a velocity1 #a nautical mile per hour1 not a distance4 ,the contemporary definition is3 #a international knot #a nautical mile per hour #a4heb kilometres per hour #a4aejggid miles per hour #j4eadddddd meters per second #fjgf4aaeb feet per hour4 #cah ,,standard ,,electrical ,,dictionary4 ,kohlrausch's ,law4 ,a law of the rate of travel of the elements and radicals in solutions under the effects of electrolysis4 ,it states that each element under the effects of electrolysis has a rate of travel for a given liquid1 which is independent of the element with which it was combined4 ,the rates of travel are stated for different elements in centimeters per hour for a potential difference of one or more volts per centimeter of path4 ,friedrich ,wilhelm ,georg ,kohlrausch 7#ahdj-aiaj7 ,kookogey's ,solution4 ,an acid exciting and depolarizing solution for a zinc-carbon couple1 such as a ,bunsen battery4 ,its formula is3 ,potassium bichromate1 #bbg parts2 water1 boiling1 #a1acd parts2 while boiling add very carefully and slowly #a1eeh parts concentrated sulphuric acid4 ,all parts are by weight4 ,use cold4 ,krizik's ,cores4 ,cores of iron for use with magnetizing coils1 q4 v4 ,they are so shaped1 the metal increasing in quantity per unit of length1 as the centre is approached1 that the pull of the excited coil upon them will as far as possible be equal in all positions4 ,a uniform cylinder is attracted with varying force according to its position2 the ,krizik bars or cores are attracted approximately uniformly through a considerable range4 ,l4 ,symbol for length and also for the unit of inductance or coefficient of induction1 because the dimensions of inductance are length4 ,lag1 ,angle of4 7a7 ,the angle of displacement of the magnetic axis of an armature of a dynamo1 due to its magnetic lag4 ,the axis of magnetism is displaced in the direction of rotation4 7,see ,magnetic ,lag47 7b7 ,the angle expressing the lag of alternating current and electro-motive force phases4 ,laminated4 adj4 ,made up of thin plates1 as a laminated armature core or converter core4 ,lamination4 ,the building up of an armature core or other thing out of plates4 ,the cores of dynamo armatures or of alternating current converters are often laminated4 ,thus a drum armature core may consist of a quantity of thin iron discs1 strung upon a rod and rigidly secured1 either with or without paper insulation between the discs4 ,if no paper is used the film of oxide on the iron is relied on for insulation4 ,the object of lamination is to break up the electrical continuity of the core1 so as to avoid ,foucault currents4 7,see ,currents1 ,foucault47 ,the laminations should be at right angles to the direction of the ,foucault currents which would be produced1 or in most cases should be at right angles to the active parts of the wire windings4 #cai ,,standard ,,electrical ,,dictionary4 ,lamination of ,armature ,conductors4 ,these are sometimes laminated to prevent the formation of eddy currents4 ,the lamination should be radial1 and the strips composing it should be insulated from each other by superficial oxidation1 oiling or enamelling1 and should be united only at their ends4 ,fig4 #baj4 ,,pilsen ,,arc ,,lamp4 ,lamp1 ,arc4 ,a lamp in which the light is produced by a voltaic arc4 ,carbon electrodes are almost universally employed4 ,special mechanism1 operating partly by spring or gravity and partly by electricity1 is employed to regulate the distance apart of the carbons1 to let them touch when no current passes1 and to separate them when current is first turned on4 ,the most varied constructions have been employed1 examples of which will be found in their places4 ,lamps may in general be divided into classes as follows1 according to their regulating mechanism and other features3 7a7 ,single light regulators or monophotes4 ,lamps through whose regulating mechanism the whole current passes4 ,these are only adapted to work singly2 if several are placed in series on the same circuit1 the action of one regulator interferes with that of the next one4 7b7 ,multiple light regulators or polyphotes4 ,in these the regulating mechanism and the carbons with their arc are in parallel2 the regulating device may be a single magnet or solenoid constituting a derived or shunt-circuit lamp1 or it may include two magnets working differentially against or in opposition to each other constituting a differential lamp4 #cbj ,,standard ,,electrical ,,dictionary4 7c7 ,lamps with fixed parallel carbons termed candles 7q4 v41 of various types74 7d7 ,lamps without regulating mechanism4 ,these include lamps with converging carbons1 whose object was to dispense with the regulating mechanism1 but which in some cases have about as much regulating mechanism as any of the ordinary arc lamps4 ,lamp1 ,contact4 ,a lamp depending for its action on loose contact between two carbon electrodes4 ,at the contact a species of incandescence with incipient arcs is produced4 ,one of the electrodes is usually flat or nearly so1 and the other one of pencil shape rests upon it4 ,lamp1 ,differential ,arc4 ,an arc lamp1 the regulation of the distance between whose carbons depends on the differential action of two separate electrical coils4 ,the diagram illustrates the principle4 ,the two carbons are seen in black2 the upper one is movable1 ,the current arrives at ,a4 ,it divides1 and the greater part goes through the low resistance coil ,m to a contact roller r1 and thence by the frame to the upper carbon1 and through the arc and lower carbon to ,b1 where it leaves the lamp4 ,a smaller portion of the current goes through the coil ,m#a of higher resistance and leaves the lamp also at ,b4 ,a double conical iron core is seen1 to which the upper carbon holder is attached4 ,this is attracted in opposite directions by the two coils4 ,if the arc grows too long its resistance increases and the coil ,m#a receiving more current draws it down and thus shortens the arc4 ,if the arc grows too short1 its resistance falls1 and the coil ,m receives more current and draws the core upwards1 thus lengthening the arc4 ,this differential action of the two cores gives the lamp its name4 ,r is a pulley over which a cord passes1 one end attached to the core and the other to a counterpoise weight1 ,w4 ,fig4 #baa4 ,,diagram ,,of ,,the ,,pilsen ,,differential ,,arc ,,lamp4 #cba ,,standard ,,electrical ,,dictionary4 ,lamp1 ,holophote4 ,a lamp designed for use alone upon its own circuit4 ,these have the regulating mechanism in series with the carbon and arc1 so that the whole current goes through both4 7,see ,lamp1 ,arc47 ,synonym--,monophote ,lamp4 ,lamp-hour4 ,a unit of commercial supply of electric energy2 the volt-coulombs required to maintain an electric lamp for one hour4 ,a sixteen-candle power incandescent lamp is practically the lamp alluded to1 and requires about half an ampere current at #aaj volts1 making a lamp-hour equal to about #aih1jjj volt-coulombs4 ,transcriber's note3 #j4ee ,,kw hours4 ,lamp1 ,incandescent4 ,an electric lamp in which the light is produced by heating to whiteness a refractory conductor by the passage of a current of electricity4 ,it is distinguished from an arc lamp 7which etymologically is also an incandescent lamp7 by the absence of any break in the continuity of its refractory conductor4 ,many different forms and methods of construction have been tried1 but now all have settled into approximately the same type4 ,the incandescent lamp consists of a small glass bulb1 called the lamp-chamber1 which is exhausted of air and hermetically sealed4 ,it contains a filament of carbon1 bent into a loop of more or less simple shape4 ,this shape prevents any tensile strain upon the loop and also approximates to the outline of a regular flame4 ,fig4 #bab4 ,,incandescent ,,electric ,,lamp4 #cbb ,,standard ,,electrical ,,dictionary4 ,the loop is attached at its ends to two short pieces of platinum wire1 which pass through the glass of the bulb and around which the glass is fused4 ,as platinum has almost exactly the same coefficient of heat-expansion as glass1 the wires do not cause the glass to crack4 ,the process of manufacture includes the preparation of the filament4 ,this is made from paper1 silk1 bamboo fibre1 tamidine1 q4 v41 or other material4 ,after shaping into the form of the filament the material is carbonized at a high heat1 while embedded in charcoal1 or otherwise protected from the air4 ,the flashing process 7see ,flashing of incandescent ,lamp ,carbons7 may also be applied4 ,the attachment to the platinum wires is effected by a minute clamp or by electric soldering4 ,the loop is inserted and secured within the open globe1 which the glass blower nearly closes1 leaving one opening for exhaustion4 ,the air is pumped out1 perhaps first by a piston pump1 but always at the end by a mercurial air pump4 7,see ,pump1 ,geissler--and others47 ,as the exhaustion becomes high a current is passed through the carbons heating them eventually to white heat so as to expel occluded gas4 ,the occluded gases are exhausted by the pump and the lamp is sealed by melting the glass with a blowpipe or blast-lamp flame4 ,for the exhaustion several lamps are usually fastened together by branching glass tubes1 and are sealed off one by one4 ,the incandescent lamps require about #c4e watts to the candle power1 or give about #ab sixteen-candle lamps to the horse power expended on them4 ,generally incandescent lamps are run in parallel or on multiple arc circuits4 ,all that is necessary in such distribution systems is to maintain a proper potential difference between the two leads across which the lamps are connected4 ,in the manufacture of lamps they are brought to an even resistance and the proper voltage at which they should be run is often marked upon them4 ,this may be fifty volts and upward4 ,one hundred and ten volts is a very usual figure4 ,as current one ampere for a fifty-volt1 or about one-half an ampere for a one hundred and ten volt lamp is employed4 ,lamp1 ,incandescent1 ,three ,filament4 ,a three filament lamp is used for three phase currents4 ,it has three filaments whose inner ends are connected1 and each of which has one leading-in wire4 ,the three wires are connected to the three wires of the circuit4 ,each filament receives a current varying in intensity1 so that there is always one filament passing a current equal to the sum of the currents in the other two filaments4 ,lamp1 ,lighthouse4 ,a special type of arc light4 ,it is adapted for use in a lighthouse dioptric lantern1 and hence its arc has to be maintained in the same position1 in the focus of the lenses4 ,the lamps are so constructed as to feed both carbons instead of only one1 thereby securing the above object4 #cbc ,,standard ,,electrical ,,dictionary4 ,lamp1 ,pilot4 ,a lamp connected to a dynamo1 and used by its degree of illumination to show when the dynamo on starting becomes excited1 or builds itself up4 ,lamp1 ,polyphote4 ,an arc lamp adapted to be used1 a number in series1 upon the same circuit4 ,the electric regulating mechanism is placed in shunt or in parallel with the carbons and arc4 7,see ,lamp1 ,arc47 ,lamps1 ,bank of4 ,a number of lamps mounted on a board or other base1 and connected to serve as voltage indicator or to show the existence of grounds1 or for other purposes4 ,lamp1 ,semi-incandescent4 ,a lamp partaking of the characteristics of both arc and incandescence2 a lamp in which the imperfect contact of two carbon electrodes produces a part of or all of the resistance to the current which causes incandescence4 ,the usual type of these lamps includes a thin carbon rod which rests against a block of carbon4 ,the species of arc formed at the junction of the two heats the carbons4 ,sometimes the upper carbon or at least its end is heated also by true incandescence1 the current being conveyed near to its end before entering it4 ,semi-incandescent lamps are not used to any extent now4 ,lamp ,socket4 ,a receptacle for an incandescent lamp2 the lamp being inserted the necessary connections with the two leads are automatically made in most sockets4 ,the lamps may be screwed or simply thrust into the socket and different ones are constructed for different types of lamps4 ,a key for turning the current on and off is often a part of the socket4 ,latent ,electricity4 ,the bound charge of static electricity4 7,see ,charge1 ,bound47 ,law of ,intermediate ,metals4 ,a law of thermo-electricity4 ,the electro-motive force between any two metals is equal to the sum of electro-motive forces between each of the two metals and any intermediate metal in the thermo-electric series1 or the electro-motive force between any two metals is equal to the sum of the electromotive forces between all the intermediate ones and the original two metals2 it is the analogue of ,volta's ,law1 q4 v4 ,law of ,inverse ,squares4 ,when force is exercised through space from a point1 its intensity varies inversely with the square of the distance4 ,thus the intensity of light radiated by a luminous point at twice a given distance therefrom is of one-fourth the intensity it had at the distance in question4 ,gravitation1 electric and magnetic attraction and repulsion and other radiant forces are subject to the same law4 #cbd ,,standard ,,electrical ,,dictionary4 ,law of ,successive ,temperatures4 ,a law of thermo-electricity4 ,the electro-motive force due to a given difference of temperature between the opposite junctions of the metals is equal to the sum of the electro-motive forces produced by fractional differences of temperature1 whose sum is equal to the given difference and whose sum exactly fills the given range of temperature4 ,law1 ,right-handed ,screw4 ,this rather crude name is given by ,emtage to a law expressing the relation of direction of current in a circuit to the positive direction of the axis of a magnet acted on by such current4 ,it is thus expressed3 ,a right-handed screw placed along the axis of the magnet and turned in the direction of the current will move in the positive direction1 i4 e41 towards the north pole of the axis of the magnet4 ,lead4 ,a metal2 one of the elements2 symbol ,pb4 ,atomic weight1 #bjg2 equivalent1 #ajc-a_/b2 valency1 #b4 ,lead may also be a tetrad1 when its equivalent is #ea4ge4 ,the following data are at #j ,c4 7#cb ,f47 with compressed metal3 ,relative ,resistance1 7,silver l7 #ac4je ,specific ,resistance1 #ai4fc microhms4 ,resistance of a wire1 7a7 #a ft4 long1 weighing #a grain1 #c4bjj ohms4 7b7 #a meter long1 weighing #a gram1 #b4bcb 7c7 #a meter long1 #a millimeter thick1 4#bdih ,resistance of #a inch cube1 #g4gbh microhms4 ,electro-,chemical ,equivalent 7,hydrogen 4#jaje7 #a4jhf mgs4 ,leading ,horns4 ,the tips of pole pieces in a dynamo1 which extend in the direction of movement of the armature4 ,leading-in ,wires4 ,the platinum wires passing through the glass of an incandescent lamp-chamber1 to effect the connection of the carbon filament with the wires of the circuit4 ,lead of ,brushes1 ,negative4 ,in a motor the brushes are set backwards from their normal position1 or in a position towards the direction of armature rotation or given a negative lead instead of a positive one1 such as is given to dynamo brushes4 ,leak4 ,a loss or escape of electricity by accidental connection either with the ground or with some conductor4 ,there are various kinds of leak to which descriptive terms are applied4 ,leakage4 ,the loss of current from conductors2 due to grounding at least at two places1 or to very slight grounding at a great many places1 or all along a line owing to poor insulation4 ,in aerial or pole telegraph lines in wet weather there is often a very large leakage down the wet poles from the wire4 7,see ,surface ,leakage--,magnetic ,leakage47 #cbe ,,standard ,,electrical ,,dictionary4 ,leakage ,conductor4 ,a conductor placed on telegraph poles to conduct directly to earth any leakage from a wire and thus prevent any but a very small portion finding its way into the other wires on the same pole4 ,it presents a choice of evils1 as it increases the electrostatic capacity of the line1 and thus does harm as well as good4 ,it consists simply of a wire grounded and secured to the pole4 ,leg of ,circuit4 ,one lead or side of a complete metallic circuit4 ,lenz's ,law4 ,a law expressing the relations of direction of an inducing current or field of force to the current induced by any disturbance in the relations between such field and any closed conductor within its influence4 ,it may be variously expressed4 7a7 ,if the relative position of two conductors1 ,a and ,b1 be changed1 of which ,a is traversed by a current1 a current is induced in ,b in such a direction that1 by its electro-dynamic action on the current in ,a1 it would have imparted to the conductors a motion of the contrary kind to that by which the inducing action was produced4 7,ganot47 7b7 ,the new 7induced7 current will increase the already existing resistances1 or develop new resistance to that disturbance of the field which is the cause of induction4 7,daniell47 7c7 ,when a conductor is moving in a magnetic field a current is induced in the conductor in such a direction as by its mechanical action to oppose the motion4 7,emtage47 7d7 ,the induced currents are such as to develop resistance to the change brought about4 ,letter ,boxes1 ,electric4 ,letter boxes with electrical connections to a bell or indicator of some sort1 which is caused to act by putting a letter into the box4 ,leyden ,jar4 ,a form of static condenser4 ,in its usual form it consists of a glass jar4 ,tinfoil is pasted around the lower portions of its exterior and interior surfaces1 covering from one-quarter to three-quarters of the walls in ordinary examples4 ,the rest of the glass is preferably shellacked or painted over with insulating varnish1 q4 v4 ,the mouth is closed with a wooden or cork stopper and through its centre a brass rod passes which by a short chain or wire is in connection with the interior coating of the jar4 ,the top of the rod carries a brass knob or ball4 ,if such a jar is held by the tinfoil-covered surface in one hand and its knob is held against the excited prime conductor of a static machine its interior becomes charged2 an equivalent quantity of the same electricity is repelled through the person of the experimenter to the earth and when removed from the conductor it will be found to hold a bound charge4 ,if the outer coating and knob are both touched or nearly touched by a conductor a disruptive discharge through it takes place4 #cbf ,,standard ,,electrical ,,dictionary4 ,fig4 #bac4 ,,leyden ,,jar ,,with ,,discharger4 ,if one or more persons act as discharging conductors they will receive a shock4 ,this is done by their joining hands1 a person at one end touching the outer coating and another person at the other end touching the knob4 ,from an influence machine a charge can be taken by connecting the coating to one electrode and the knob to the other4 ,fig4 #bad4 ,,sulphuric ,,acid ,,leyden ,,jar4 #cbg ,,standard ,,electrical ,,dictionary4 ,leyden ,jar1 ,sir ,william ,thomson's4 ,an especially efficient form of ,leyden jar4 ,it consists of a jar with outer tinfoil coating only4 ,for the interior coating is substituted a quantity of concentrated sulphuric acid4 ,the central rod is of lead with a foot1 which is immersed in the acid and from which the rod rises4 ,a wooden cover partly closes the jar1 as the central tube through which the rod passes is so large as not to allow the wood to touch it4 ,thus any leakage from inner to outer coating has to pass over the inside and outside glass surfaces4 ,in the common form of jar the wooden cover may short circuit the uncoated portion of the inner glass surface4 ,in the cut a simplified form of ,thomson's ,leyden jar is shown1 adapted for scientific work4 ,lichtenberg's ,figures4 ,if the knob of a ,leyden jar or other exited electrode is rubbed over the surface of ebonite1 shellac1 resin or other non-conducting surface it leaves it electrified in the path of the knob4 ,if fine powder such as flowers of sulphur or lycopodium is dusted over the surface and the excess is blown away1 the powder will adhere where the surface was electrified1 forming what are called ,lichtenberg's ,figures1 ,lycopodium and sulphur show both positive and negative figures1 that is to say1 figures produced by a positively or negatively charged conductor4 ,red lead adheres only to negative figures4 ,if both positive and negative figures are made and the surface is sprinkled with both red lead and flowers of sulphur each picks out its own figure1 the sulphur going principally to the positive one4 ,the red lead takes the form of small circular heaps1 the sulphur arranges itself in tufts with numerous diverging branches4 ,this indicates the difference in the two electricities4 ,the figures have been described as a very sensitive electrosope for investigating the distribution of electricity on an insulating surface4 7,ganot47 ,life of ,incandescent ,lamps4 ,the period of time a lamp remains in action before the carbon filament is destroyed4 ,the cause of a lamp failing may be the volatilization of the carbon of the filament1 causing it to become thin and to break2 or the chamber may leak4 ,the life of the lamp varies2 #fjj hours is a fair estimate4 ,sometimes they last several times this period4 ,the higher the intensity at which they are used the shorter is their life4 ,from their prime cost and the cost of current the most economical way to run them can be approximately calculated4 ,transcriber's note3 ,contemporary incandecent buls are rated for #ajjj hours2 flourescent bulbs up to #bdjjj hours2 ,,led lamps up to #ajjjjj hours4 ,lightning4 ,the electrostatic discharge to the earth or among themselves of clouds floating in the atmosphere4 ,the discharge is accompanied by a spark or other luminous effect1 which may be very bright and the effects1 thermal and mechanical1 are often of enormous intensity4 ,the lightning flash is white near the earth1 but in the upper regions where the air is rarefied it is of a blue tint1 like the spark of the electric machine4 ,the flashes are often over a mile in length1 and sometimes are four or five miles long4 ,they have sometimes a curious sinuous and often a branching shape1 which has been determined by photography only recently4 ,to the eye the shape seems zigzag4 #cbh ,,standard ,,electrical ,,dictionary4 ,in the case of a mile-long flash it has been estimated that #c1eaf1dhj ,de la ,rue cells1 q4 v41 would be required for the development of the potential1 giving the flash over three and one-half millions of volts4 ,but as it is uncertain how far the discharge is helped on its course by the rain drops this estimate may be too high4 ,there are two general types of flash4 ,the so-called zigzag flash resembles the spark of an electric machine1 and is undoubtedly due to the disruptive discharge from cloud to earth4 ,sheet lightning has no shape1 simply is a sudden glow1 and from examination of the spectrum appears to be brush discharges 7see ,discharge1 ,brush7 between clouds4 ,heat lightning is attributed to flashes below the horizon whose light only is seen by us4 ,globe or ball lightning takes the form of globes of fire1 sometimes visible for ten seconds1 descending from the clouds4 ,on reaching the earth they sometimes rebound1 and sometimes explode with a loud detonation4 ,no adequate explanation has been found for them4 ,the flash does not exceed one-millionth of a second in duration2 its absolute light is believed to be comparable to that of the sun1 but its brief duration makes its total light far less than that of the sun for any period of time4 ,if the disruptive discharge passes through a living animal it is often fatal4 ,as it reaches the earth it often has power enough to fuse sand1 producing fulgurites1 q4 v4 7,see also ,back ,shock or ,stroke of ,lightning47 ,volcanic lightning1 which accompanies the eruptions of volcanoes1 is attributed to friction of the volcanic dust and to vapor condensation4 ,transcriber's note3 ,the origin of lightning is still 7#bjjh7 not fully understood1 but is thought to relate to charge separation in the vertical motion of water droplets and ice crystals in cloud updrafts4 ,a lightning bolt carries a current of #dj1jjj to #abj1jjj amperes1 and transfers a charge of about five coulombs4 ,nearby air is heated to about #aj1jjj ,c 7#ah1jjj ,f71 almost twice the temperature of the ,sun's surface4 ,lightning ,arrester4 ,an apparatus for use with electric lines to carry off to earth any lightning discharge such lines may pick up4 ,such discharge would imperil life as well as property in telegraph offices and the like4 ,arresters are generally constructed on the following lines4 ,the line wires have connected to them a plate with teeth2 a second similar plate is placed near this with its teeth opposite to those of the first plate and nearly touching it4 ,the second plate is connected by a low resistance conductor to ground4 ,any lightning discharge is apt to jump across the interval1 of a small fraction of an inch1 between the oppositely placed points and go to earth4 ,another type consists of two plates1 placed face to face1 and pressing between them a piece of paper or mica4 ,the lightning is supposed to perforate this and go to earth4 ,one plate is connected to the line1 the other one is grounded4 ,the lightning arrester is placed near the end of the line before it reaches any instrument4 7,see ,alternative ,paths47 #cbi ,,standard ,,electrical ,,dictionary4 ,fig4 #bae4 ,,comb ,,or ,,toothed ,,lightning ,,arrester4 ,fig4 #baf4 ,,film ,,or ,,plate ,,lightning ,,arrester4 ,lightning ,arrester1 ,counter-electro-motive ,force4 ,an invention of ,prof4 ,elihu ,thompson4 ,a lightning arrester in which the lightning discharge sets up a counter-electro-motive force opposed to its own4 ,this it does by an induction coil4 ,if a discharge to earth takes place it selects the primary of the coil as it has low self-induction4 ,in its discharge it induces in the secondary a reverse electro-motive force which protects the line4 ,lightning ,arrester ,plates4 ,the toothed plates nearly in contact1 tooth for tooth1 or the flat plates of a film lightning arrester1 which constitute a lightning arrester4 ,some advocate restricting the term to the plate connected to the line4 ,lightning ,arrester1 ,vacuum4 ,a glass tube1 almost completely exhausted1 into which the line wire is fused1 while a wire leading to an earth connection has its end fused in also4 ,a high tension discharge1 such as that of lightning1 goes to earth across the partial vacuum in preference to going through the line1 which by its capacity and self-induction opposes the passage through it of a lightning discharge4 ,it is especially adapted for underground and submarine lines4 #ccj ,,standard ,,electrical ,,dictionary4 ,lightning1 ,ascending4 ,lightning is sometimes observed which seems to ascend4 ,it is thought that this may be due to positive electrification of the earth and negative electrification of the clouds4 ,lightning1 ,globe or ,globular4 ,a very unusual form of lightning discharge1 in which the flashes appear as globes or balls of light4 ,they are sometimes visible for ten seconds1 moving so slowly that the eye can follow them4 ,they often rebound on striking the ground1 and sometimes explode with a noise like a cannon4 ,they have never been satisfactorily explained4 ,sometimes the phenomenon is probably subjective and due to persistence of vision4 ,lightning ,jar4 ,a ,leyden jar whose coatings are of metallic filings dusted on to the surface while shellacked1 and before the varnish has had time to dry4 ,in its discharge a scintillation of sparks appears all over the surface4 ,line of ,contact4 ,the line joining the points of contact of the commutator brushes in a dynamo or motor4 ,synonym--,diameter of ,commutation4 ,lines of ,force4 ,imaginary lines denoting the direction of repulsion or attraction in a field of force1 q4 v4 ,they may also be so distributed as to indicate the relative intensity of all different parts of the field4 ,they are normal to equipotential surfaces4 7,see ,electro-magnetic ,lines of ,force--,electrostatic ,lines of ,force--,magnetic ,lines of ,force47 ,lines of ,induction4 ,imaginary lines within a body marking the direction taken within it by magnetic induction4 ,these are not necessarily parallel to lines of force1 but may1 in bodies of uniform agglomeration1 or in crystalline bodies1 take various directions4 ,synonym--,lines of ,magnetic ,induction4 ,lines of ,slope4 ,lines in a field of force which mark the directions in which the intensity of force in the field most rapidly falls away4 ,links1 ,fuse4 ,links made of more or less easily fusible metal1 for use as safety fuses4 ,listening ,cam4 ,in a telephone exchange a cam or species of switch used to connect the operator's telephone with a subscriber's line4 #cca ,,standard ,,electrical ,,dictionary4 ,lithanode4 ,a block of compressed lead binoxide1 with platinum connecting foils for use as an electrode in a storage battery4 ,it has considerable capacity1 over #e ampere-hours per pound of plates1 but has not met with any extended adoption4 ,load4 ,in a dynamo the amperes of current delivered by it under any given conditions4 ,local ,action4 7a7 ,in its most usual sense the electric currents within a battery1 due to impurities in the zinc1 which currents may circulate in exceedingly minute circuits1 and which waste zinc and chemicals and contribute nothing to the regular current of the battery4 ,amalgamated or chemically pure zinc develops no local action4 7b7 ,the term is sometimes applied to currents set up within the armature core or pole pieces of a dynamo4 7,see ,currents1 ,foucault47 ,local ,battery4 ,a battery supplying a local circuit 7q4 v472 in telegraphy1 where it is principally used1 the battery is thrown in and out of action by a relay1 and its current does the work of actuating the sounder and any other local or station instruments4 7,see ,relay47 ,local ,circuit4 ,a short circuit on which are placed local apparatus or instruments4 ,such circuit is of low resistance and its current is supplied by a local battery1 q4 v4 ,its action is determined by the current from the main line throwing its battery in and out of circuit by a relay1 q4 v41 or some equivalent4 ,local ,currents4 ,currents within the metal parts of a dynamo4 7,see ,currents1 ,foucault47 ,in a galvanic battery4 where there is local action1 q4 v41 there are also local currents1 though they are not often referred to4 ,localization4 ,determining the position of anything1 such as a break in a cable1 or a grounding in a telegraph line4 ,in ocean cables two typical cases are the localization of a break in the conductor and of a defect in the insulation admitting water4 ,the first is done by determining the static capacity of the portion of the line which includes the unbroken portion of the conductor2 the other by determining the resistance of the line on a grounded circuit4 ,locus4 ,a place4 ,the word is used to designate the locality or position of1 or series of positions of definite conditions and the like4 ,thus an isogonic line is the locus of equal declinations of the magnetic needle2 it is a line passing through all places on the earth's surface where the condition of a given declination is found to exist4 #ccb ,,standard ,,electrical ,,dictionary4 ,lodestone4 ,magnetic magnetite2 magnetite is an ore of iron1 ,fe#c #jd which is attracted by the magnet4 ,some samples possess polarity and attract iron4 ,the latter are lodestones4 ,synonym--,hercules ,stone ,logarithm4 ,the exponent of the power to which it is necessary to raise a fixed number to produce a given number4 ,the fixed number is the base of the system4 ,there are two systems2 one1 called the ordinary system1 has #aj for its base1 the other1 called the ,naperian system1 has #b4gahbh for its base4 ,the latter are also termed hyperbolic logarithms1 and are only used in special calculations4 ,log1 ,electric4 ,an apparatus for measuring the speed of a ship4 ,a rotating helical vane of known pitch is dragged behind the vessel4 ,as the helix rotates its movements may actuate electric machinery for registering its rotations4 ,the number of these in a given time1 multiplied by the pitch of the vane1 gives the distance traversed in such time4 ,loop4 ,a portion of a circuit introduced in series into another circuit4 ,the latter circuit is opened by a spring-jack1 q4 v4 or other device1 and the loop inserted4 ,by loops any number of connections can be inserted into a circuit in series therewith1 and in series or in parallel with one another4 ,loop ,break4 ,a double bracket or similar arrangement for holding on insulators the ends of a conductor which is cut between them1 and to which are connected the ends of a loop4 ,the space between the insulators may be about a foot4 ,luces4 ,this may be used as the plural of lux1 q4 v4 ,it is the ,latin plural4 ,luminous ,jar4 ,a ,leyden jar whose coatings are of lozenge-shaped pieces of tinfoil between which are very short intervals4 ,when discharged1 sparks appear all over the surface where the lozenges nearly join4 ,lux4 ,a standard of illumination1 q4 v41 as distinguished from illuminating power4 ,it is the light given by one candle at a distance of #ab4g inches--by a carcel1 q4 v41 at a distance of one meter---or by #aj1jjj candles at #aje4h feet4 ,it was proposed by ,w4 ,h4 ,preece4 ,all the above valuations are identical4 ,m4 7a7 ,symbol of gaseous pressure equal to one-millionth of an atmosphere4 7b7 ,the ,greek m1 1 is used as the symbol of magnetic permeability4 #ccc ,,standard ,,electrical ,,dictionary4 ,machine1 ,cylinder ,electric4 ,a frictional electric machine whose rotating glass is in the shape of a cylinder instead of a disc as in the more recent machines4 ,fig4 #bag4 ,,plate ,,frictional ,,electric ,,machine4 ,machine1 ,frictional ,electric4 ,an apparatus for development of high tension electricity by contact action1 brought about by friction4 ,it consists of a plate or cylinder of glass mounted on insulating standards and provided with a handle for turning it4 ,one or more cushions of leather are held on an insulated support1 so as to rub against the plate or cylinder as it is turned4 ,a metal comb or combs are held on another insulating support so as to be nearly in contact with the surface of the glass plate at a point as far removed as possible from the rubbers4 ,the combs are attached to a brass ball or round-ended cylinder1 which is termed the prime conductor4 ,in use either the prime conductor or cushions are connected by a chain or otherwise with the earth4 ,assume it to be the cushions4 ,as the machine is worked by turning the plate1 the glass and cushion being in contact develop opposite electricities4 ,the glass is charged with positive electricity1 and as it turns carries it off and as it reaches the prime conductor by induction and conduction robs it of its negative electricity4 ,meanwhile the cushions negatively excited deliver their charge to the earth4 ,the action thus goes on1 the prime conductor being charged with positive electricity4 #ccd ,,standard ,,electrical ,,dictionary4 ,if the prime conductor is connected to the earth and the cushions are left insulated1 negative electricity can be collected from the cushions4 ,in some machines both prime conductor and cushions are kept insulated and without ground contact4 ,electrodes connecting with each are brought with their ends close enough to maintain a sparking discharge4 ,machine ,influence4 ,a static electric machine working by induction to build up charges of opposite nature on two separate prime conductors4 ,in general they are based on the principle of the electrophorous4 ,work is done by the operator turning the handle4 ,this rotates a disc and draws excited parts of it away from their bound charges4 ,this represents a resistance to mechanical motion4 ,the work absorbed in overcoming this mechanical resistance appears as electric energy4 ,there are various types of influence machines1 the ,holtz1 ,toeppler-,holtz and ,wimshurst being the most used4 ,the electrophorous1 q4 v41 is a type of influence machine4 ,machine1 ,holtz ,influence4 ,a static electric machine4 ,it includes two plates1 one of which is rapidly rotated in front of the other4 ,two armatures of paper are secured to the back of the stationary plate at opposite ends of a diameter4 ,to start it one of these is charged with electricity4 ,this charge by induction acts through the two thicknesses of glass upon a metal bar carrying combs1 which lies in front of the further side of the movable plate4 ,the points opposite the armature repel electrified air1 which strikes the movable disc and charges it4 ,a second rod with comb at the opposite end of the same diameter acts in the reverse way4 ,thus opposite sections of the disc are oppositely charged and the combs with them4 ,by induction these portions of the disc react upon the two armatures4 ,the opposite electricities escape from the armatures by paper tongues which are attached thereto and press against the back of the movable plate4 ,as the plate rotates the opposite electricities on its face neutralize the electricity repelled from the combs4 ,the charges on the back strengthen the charges of the armatures and brass combs4 ,thus the machine builds up1 and eventually a discharge of sparks takes place from the poles of the brass combs4 #cce ,,standard ,,electrical ,,dictionary4 ,machine1 ,toeppler-,holtz4 ,a modification of the ,holtz machine4 ,the priming charge of the armatures is produced by friction of metallic brushes against metallic buttons on the face of the rotating plate4 7,see ,machine1 ,holtz47 ,machine1 ,wimshurst4 ,a form of static influence machine4 ,it consists of two plates of glass1 on which radial sectors of tinfoil are pasted4 ,both plates are rotated in opposite directions4 ,the sectors of the two plates react one upon the other1 and electric charges of opposite sign accumulate on the opposite sides of the plates and are collected therefrom by collecting combs4 ,mack4 ,a name1 derived from ,maxwell1 and suggested for the unit of inductance4 ,it is due to ,oliver ,heaviside1 but has never been adopted4 7,see ,henry47 ,magne-,crystallic ,action4 ,the action of a supposed force of the same name1 proposed by ,faraday4 ,it relates to the different action of a magnetic field upon crystalline bodies1 according to the position of their axes of crystallization4 ,a needle of tourmaline1 normally paramagnetic1 if poised with its axis horizontal1 is diamagnetic4 ,bismuth illustrates the same phenomenon4 ,the subject is obscure4 ,faraday thought that he saw in it the action of a specific force4 ,magnet4 ,a body which tends when suspended by its centre of gravity to lay itself in a definite direction1 and to place a definite line within it1 its magnetic axis1 q4 v41 in a definite direction1 which1 roughly speaking1 lies north and south4 ,the same bodies have the power of attracting iron 7,daniell71 also nickel and cobalt4 ,magnets are substances which possess the power of attracting iron4 7,ganot47 ,transcriber's note3 ,edward ,purcell and others have explained magnetic and electromagnetic phenomenon as relativistic effects related to electrostatic attraction4 ,magnetism is caused by ,lorentz contraction of space along the direction of a current4 ,electromagnetic waves are caused by charge acceleration and the resulting disturbance of the electrostatic field4 7,electricity and ,magnetism3 ,berkeley ,physics ,course ,volume #b1 #aifj7 ,magnet1 ,anomalous4 ,a magnet possessing more than the normal number 7two7 of poles4 ,if two straight magnets are placed end to end with their south poles in juxtaposition the compound bar will seem to possess three poles1 one at each end and one in the middle4 ,the apparent pole in the middle is really made up of two consequent poles1 q4 v4 ,it sometimes happens that when a single long thin bar is magnetized consequent poles are produced1 although such magnet is in one piece4 ,this may be accidental1 as in such case it is quite hard to avoid anomalous poles1 or1 as in the field magnets of some forms of dynamos1 anomalous poles may be purposely produced4 ,magnet1 ,artificial4 ,a magnet formed artificially by any method of magnetization 7see ,magnetism7 applicable to permanent magnets1 electro-magnets and solenoids4 ,it expresses the distinction from the natural magnets or lodestone1 q4 v4 ,it is made of steel in practice magnetized by some of the methods described under ,magnetization4 #ccf ,,standard ,,electrical ,,dictionary4 ,magnet1 ,axial4 ,a straight-solenoid with axial core4 ,magnet1 ,bar4 ,a bar magnet is one in the shape of a bar1 i4 c41 straight with parallel sides and considerably longer than wide or deep4 ,magnet1 ,bell-shaped4 ,a form of permanent magnet used in some galvanometers4 ,in shape it is a thick-sided cylindrical box with two slots cut out of opposite sides1 so as to make it represent a horseshoe magnet4 ,its shape enables it to be surrounded closely by a mass of copper1 for damping its motion1 to render the instrument dead-beat4 ,such a magnet is used in ,siemens ,halske's galvanometer4 ,magnet ,coil4 ,a coil to be thrust over an iron core1 to make an electro-magnet4 ,they are often wound upon paper or wooden bobbins or spools1 so as to be removable from the core if desired4 ,magnet1 ,compensating4 7a7 ,a magnet fastened near a compass on an iron or steel ship to compensate the action of the metal of the ship upon the magnetic needle4 ,the ship itself always has some polarity and this is neutralized by one or more compensating magnets4 7b7 ,see below4 ,magnet1 ,controlling4 ,a magnet attached to a galvanometer by which the directive tendency of its magnetic needle is adjusted4 ,in the reflecting galvanometer it often is a slightly curved magnet carried by a vertical brass spindle rising from the center of the instrument1 and which magnet may be slid up and down on the spindle to regulate or adjust its action4 ,synonym--,compensating ,magnet4 ,magnet1 ,compound4 ,a permanent magnet1 built up of a number of magnets4 ,small bars can be more strongly magnetized than large4 ,hence a compound magnet may be made more powerful than a simple one4 ,magnet ,core4 ,the iron bar or other mass of iron around which insulated wire is wound for the production of an electro-magnet4 ,the shapes vary greatly1 especially for field magnets of dynamos and motors4 ,for these they are usually made of cast iron1 although wrought iron is preferable from the point of view of permeability4 ,magnet1 ,damping4 ,a damping magnet is one used for bringing an oscillating body to rest4 ,the body may be a metallic disc or needle1 and the action of the magnet depends on its lines of force which it establishes1 so that the body has to cut them1 and hence has its motion resisted4 #ccg ,,standard ,,electrical ,,dictionary4 ,magnet1 ,deflection of4 ,the change of position of a magnet from the plane of the earth's meridian in which it normally is at rest into another position at some angle thereto1 by the effect of an artificial magnetic field1 as the deflection of a galvanometer needle4 ,magnet1 ,electro-4 ,a magnet consisting of a bar of iron1 bundle of iron wires1 iron tube or some equivalent1 around which a coil of insulated wire is wound4 ,such combination becomes polarized when a current is passed through it and is an active magnet4 ,on the cessation of the current its magnetism in part or almost completely disappears4 7,see ,electro-magnet47 ,magnet1 ,equator of4 ,in a magnet the locus of points of no attractive power and of no polarity4 ,in a symmetrical1 evenly polarized magnet it is the imaginary line girdling the centre4 ,the terms ,neutral ,point or ,neutral ,line have displaced it4 ,synonyms--,neutral ,line--,neutral ,point4 ,magnet1 ,field4 ,a magnet1 generally an electro-magnet1 used to produce the field in a dynamo or motor4 ,magnet1 ,haarlem4 ,celebrated magnets made in ,haarlem1 ,holland4 ,logeman1 ,van ,wetteren1 ,funckler and ,van der ,willigen were the makers who gave the celebrity to the magnets4 ,they were generally horseshoe magnets1 and would carry about twenty times their own weight4 ,magnet1 ,horseshoe4 ,a magnet of ,u shape--properly one with the poles brought a little closer together than the rest of the limbs4 ,for direct lifting and attractive effects it is the most generally adopted type4 ,its advantage as regards lifting effect is due to small reluctance1 q4 v41 offered by a complete iron circuit1 such as the armature and magnet together produce4 ,as the term is now used it is applied to any ,u shaped magnet4 ,fig4 #bah4 ,,joule',s ,,electro-,,magnet4 ,magnet1 ,joule's ,electro4 ,an electro-magnet of the shape of a cylinder with a longitudinal segment cut-off4 ,it is wound with wire as shown4 ,the segment cut-off is a piece of the same shape as the armature4 ,it is of high power4 #cch ,,standard ,,electrical ,,dictionary4 ,magnetic ,adherence4 ,the tendency of a mass of iron to adhere to the poles of a magnet4 ,it is best figured as due to the virtual shortening of lines of force1 as the more permeable iron gives a better path for them than the air can afford1 and consequently a virtually shorter one4 ,magnetic ,attraction and ,repulsion4 ,the attraction of a magnet for iron1 steel1 nickel and cobalt and of unlike poles of magnets for each other4 ,it is identical with electro-magnetic attraction1 q4v4 7,also see ,electro-magnetism47 ,magnetic ,attraction and ,repulsion1 ,coulomb's ,law of4 ,magnetic attraction and repulsion are inversely as the square of the distance4 7,ganot47 ,while theoretically true in the case of isolated poles1 in practise it does not generally apply on account of the large diameter and relative shortness of magnets4 ,magnetic ,axis4 ,the line connecting the poles of a magnet4 ,it does not generally coincide exactly with any symmetrical axis of figure4 ,in such cases an error is introduced into the indications of the needle which must be determined and allowed for in compasses4 ,to determine it with a magnetic needle the suspension cup is made removable1 so that the needle can be reversed4 ,readings are taken with one side of the needle and then with the other side of the needle up1 and the average corresponds with the position of the magnetic axis in both positions of the needle4 ,magnetic ,azimuth4 ,the angle1 measured on a horizontal circle1 between the magnetic meridian and a great circle of the earth passing through the observer and any observed body4 ,it is the astronomical azimuth of a body referred to the magnetic meridian and therefore subject to the variation of the compass4 ,the angle is the magnetic azimuth of the observed body4 ,magnetic ,battery4 ,a name for a compound permanent magnet2 one made up by bolting or clamping together1 or to single soft iron pole pieces1 a number of single permanent magnets4 ,there are a number of forms of compound magnets4 ,in making them care has to be taken to have them of even strength4 ,it is also well to have them slightly separated4 ,the object of both these precautions is to prevent a stronger element or magnet from depolarizing its neighbor4 ,synonym--,compound ,magnet4 ,magnetic ,bridge4 ,an apparatus for testing the relative permeability of iron4 ,it consists of a rectangular system of iron cores4 ,three of the sides are wound with wire as shown4 ,the other side is built up of double bars1 and from the centre two curved arms rise1 as shown in the cut4 ,the arms do not touch4 ,between them a short magnet is suspended by a filament1 which also carries a mirror and an index4 #cci ,,standard ,,electrical ,,dictionary4 ,fig4 #bai4 ,,magnetic ,,bridge4 ,a lamp and scale are provided as in the reflecting galvanometer4 ,when adjusted the magnetic needle hangs as shown in the cut1 ,fig4 #bai1 without any tendency to turn towards either curved pole piece4 ,if all iron parts are symmetrical and of similar metal1 a current through the coils will make no difference4 ,it will work in magnetic opposition upon the two arms1 or1 in other words1 will maintain both arms at identical potential4 ,fig4 #bbj4 ,,pole ,,pieces1 ,,magnetic ,,needle ,,and ,,mirror ,,of ,,magnetic ,,bridge4 ,if there is the least difference in permeability1 length or thickness between any of the iron bars the magnetic potential of the two curved arms will differ1 and the magnetic needle will turn one way or the other4 ,in practical use different samples of iron are substituted for the unwound members of the fourth side of the parallelogram1 and the needle by its motions indicates the permeability4 ,in the cut1 ,fig4 #bbj1 ,d ,d are the ends of the curved pole pieces2 ,a the wire carrying the mirror ,b and magnetic needle ,n1 and ,e is the index which shows the larger deflections4 #cdj ,,standard ,,electrical ,,dictionary4 ,magnetic ,circuit4 ,a magnetic field of force is characterized by the presence of lines of force1 which1 while approximately parallel1 curve around and tend to form closed curves4 ,the polarity of a field of force is referred to an imaginary direction of the lines of force from the north pole through space to the south pole1 and in the part of the field corresponding to the body of the magnet1 from the south to the north pole4 ,the cut indicates these features4 ,hence the magnetic field of force is termed the magnetic circuit1 and to it are attributed a species of resistance termed reluctance1 q4 v41 and the producing cause of the field or lines of force is termed sometimes magneto-motive force1 q4 v47 corresponding to the electro-motive force4 ,the modern treatment of the magnetic circuit is similar to the application of ,ohm's law and the laws of resistance and conductivity to the electric circuit4 ,magnetic ,circuit1 ,double4 ,a magnetic circuit which virtually represents two horseshoe magnets placed with their like poles in contact4 ,it is used for field magnets1 the armatures occupying a place between the consequent poles4 ,fig4 #bba4 ,,one-,,half ,,portion ,,of ,a ,,double ,,magnetic ,,circuit4 ,magnetic ,concentration of ,ores4 ,the concentration of ores or the freeing them from their gangue by magnetic attraction4 ,it is only applicable to those cases in which either the ore itself or the gangue is attracted by the magnet4 ,its principal application is to the concentration of magnetic iron sands4 7,see ,magnetic ,concentration47 ,magnetic ,concentrator4 ,an apparatus similar to a magnetic separator1 q4 v41 but used to concentrate magnetic iron sands4 ,by the action of electro-magnets the magnetic iron sand 7magnetite7 is separated from the sand with which it is mixed4 ,magnetic ,conductivity and ,conductance4 ,the first notion of permeance and of the magnetic circuit included the idea of magnetic conductivity1 which conducted lines of force urged by magneto-motive force through a magnetic circuit4 ,the terms are displaced by permeability and permeance4 #cda ,,standard ,,electrical ,,dictionary4 ,magnetic ,continuity4 ,the completeness of a magnetic circuit1 as when the armature of a horseshoe magnet is in contact with both poles4 ,it is an attribute of a paramagnetic substance only and is identical for permanent magnets or for electro-magnets4 ,an air space intervening between armature and magnet poles1 or a space filled with any diamagnetic substance prevents continuity1 although the lines of force to some extent still find their way around4 ,the leakage is increased by discontinuity4 ,magnetic ,control4 ,control of a magnetic needle1 magnet1 iron index or armature1 in a galvanometer1 ammeter or voltmeter by a magnetic field2 the restitutive force being derived from a permanent magnet4 ,magnetic ,couple4 ,the couple of magnetic force which tends to bring the magnetic needle into the plane of the magnetic meridian4 ,one force is represented by the imaginary pull upon the north pole1 and the other by the opposite pull upon the south pole of the needle4 ,the moment of the couple varies from a maximum when the needle is at right angles to the plane of the magnetic meridian to zero when it is in such plane4 ,magnetic ,creeping4 ,viscous hysteresis2 the slow increase of magnetism in a paramagnetic body when exposed to induction4 ,fig4 #bbb4 ,,magnetic ,,curves ,,or ,,figures4 ,magnetic ,curves4 ,the pictorial representation of magnetic lines of force4 ,it is generally produced by scattering filings on a sheet of paper or pane of glass held over a magnet4 ,the filings arrange themselves in characteristic curves4 ,tapping the paper or pane of glass facilitates the arrangement1 or jarring the filings off a smaller magnet1 so that they fall polarized upon the paper1 is thought by some to improve the effect4 ,the group of curves forms what are termed magnetic figures1 q4 v4 #cdb ,,standard ,,electrical ,,dictionary4 ,magnetic ,declination4 ,the angular deviation of the magnetic needle1 causing it to rest at an angle with the true meridian2 the variation of the compass4 7,see ,magnetic ,elements47 ,magnetic ,density4 ,the intensity of magnetization expressed in lines of force per stated area of cross-section in a plane at right angles to the lines of force4 ,magnetic ,dip4 ,the inclination from the horizontal assumed by a magnetic needle free to move in the vertical plane4 7,see ,magnetic ,elements47 ,the angle of dip or inclination is entirely a function of the earth1 not of the needle4 ,magnetic ,discontinuity4 ,a break or gap in a magnetic circuit4 ,to make a complete circuit the iron or other core must be continuous4 ,if the armature of a horseshoe magnet is in contact with both poles the continuity is complete4 ,if the armature is not in contact magnetic continuity gives place to discontinuity4 ,it is an attribute of a paramagnetic substance only1 and is identical for permanent magnets1 or for electro-magnets4 ,magnetic ,elements4 ,the qualities of the terrestrial magnetism at any place as expressed in its action upon the magnetic needle4 ,three data are involved4 ,i4 ,the ,declination or ,variation4 ,,ii4 ,the ,inclination or ,dip4 ,,iii4 ,the ,force or ,intensity4 ,i4 ,the ,declination is the variation expressed in angular degrees of the magnetic needle from the true north and south1 or is the angle which the plane of the magnetic meridian makes with that of the geographical meridian4 ,it is expressed as east or west variation according to the position of the north pole2 east when the north pole of the needle is to the east of the true meridian1 and vice versa4 ,declination is different for different places2 it is at present west in ,europe and ,africa1 and east in ,asia and the greater part of ,north and ,south ,america4 ,the declination is subject to 7a7 secular1 7b7 annual and 7c7 diurnal variations4 ,these are classed as regular2 others due to magnetic storms are transitory and are classed as irregular1 7a7 ,secular variations4 ,the following table shows the secular variations during some three hundred years at ,paris4 ,these changes are termed secular1 because they require centuries for their completion4 #cdc ,,standard ,,electrical ,,dictionary4 ,table of ,declination or ,variation at ,paris4 ,year4 ,declination4 #aehj #aa #cj' ,e4 #affc #j #agjj #h #aj' ,w4 #aghj #ai #ee' ,w4 #aghe #bb #jj' ,w4 #ahje #bb #e' ,w4 #ahad #bb #cd' ,w4 #ahbe #bb #bb' ,w4 #ahcj #bb #ab' ,w4 #ahce #bb #d' ,w4 #ahej #bj #cj' ,w4 #ahee #ai #eg' ,w4 #ahfj #ai #cb' ,w4 #ahfe #ah #dd' ,w4 #ahge #ag #ba' ,w4 #ahgh #ag #jj' ,w4 ,transcriber's note ,the value for #bjjh is about #j #dh' ,w1 changing by #j #g' ,e_/year4 ,on scrutinizing these figures it will be seen that there is part of a cycle represented and that the declination is slowly returning to the zero point after having reached its maximum western variation in #ahad4 ,upwards of #cjj years would be required for its completion on the basis of what is known4 ,in other places1 notably the coast of ,newfoundland1 the ,gulf of the ,st4 ,lawrence and the rest of the ,north ,american seaboard and in the ,british ,channel1 the secular variations are much more rapid in progress4 7b7 ,annual variations--,these were first discovered in #aghj by ,cassini4 ,they represent a cycle of annual change of small extent1 from #ae' to #ah' only4 ,in ,paris and ,london the annual variation is greatest about the vernal equinox1 or ,march #bast1 and diminishes for the next three months1 and slowly increases again during the nine following months4 ,it varies during different epochs4 7c7 ,diurnal variations were discovered in #agbb by ,graham4 ,a long needle has to be employed1 or the reflection of a ray of light1 as in the reflecting galvanometer1 has to be used to observe them4 ,in ,england the north pole of the magnetic needle moves every day from east to west from sunrise until #a or #b ,p4 ,m42 it then tends towards the east and recovers its original position by #aj ,p4 ,m4 ,during the night the needle is almost stationary4 ,as regards range the mean amplitude of diurnal variations at ,paris is from ,april to ,september #ac' to #ae'2 for the other months from #h' to #aj'4 ,on some days it amounts to #be' and sometimes is no more than #e'4 ,the amplitude of diurnal variations decreases from the poles to the equator4 ,irregular variations accompany earthquakes1 the aurora borealis and volcanic eruptions4 ,in ,polar regions the auroral variations may be very great2 even at #dj latitude they may be #a or #b4 ,simultaneous irregularities sometimes extend over large areas4 ,such are attributed to magnetic storms4 ,,ii4 ,the ,inclination is the angle which the magnetic needle makes with the horizon1 when the vertical plane in which the needle is assumed to be free to move coincides with the magnetic meridian4 ,it is sometimes called the dip of the needle4 ,it varies as does the declination1 as shown in the following table of inclinations of ,london4 #cdd ,,standard ,,electrical ,,dictionary4 ,table of ,inclination or ,dip at ,london ,year4 ,inclination4 #aegf #ga #ej' #afjj #gb #afgf #gc #cj' #agbc #gd #db' #aggc #gb #ai' #aghj #gb #h' #agij #ga #cc' #ahjj #gj #ce' #ahba #gj #ca' #ahbh #fi #dg' #ahch #fi #ag' #ahed #fh #ca' #ahei #fh #ba' #ahgd #fg #dc' #ahgf #fg #ci' #ahgh #fg #cf' #ahhj #fg #ce' #ahha #fg #ce' ,,iii4 ,force or ,intensity is the directive force of the earth4 ,it varies with the squares of the number of oscillations the magnetic needle will make if caused to oscillate from a determined initial range4 ,the intensity is supposed to be subject to secular change4 ,according to ,gauss the total magnetic intensity of the earth is equal to that which would be exerted if in each cubic yard there were eight bar magnets1 each weighing one pound4 ,this is1 of course1 a rough way of expressing the degree of intensity4 ,intensity is least near the magnetic equator and greatest near the magnetic poles2 the places of maximum intensity are termed the magnetic foci4 ,it varies with the time of day and possibly with changes in altitude4 ,magnetic ,elongation4 ,the elongation a bar of iron or steel undergoes when magnetized4 ,by magnetization it becomes a little longer and thinner1 there being no perceptible change in volume4 ,the change is accompanied by a slight sound--the magnetic tick4 ,an exceedingly delicate adjustment of apparatus is required for its observation4 ,magnetic ,equator4 ,a locus of the earth's surface where the magnet has no tendency to dip4 ,it is1 approximately speaking1 a line equally distant from the magnetic poles1 and is called also the aclinic line4 ,it is not a great circle of the earth4 #cde ,,standard ,,electrical ,,dictionary4 ,magnetic ,field of ,force4 ,the field of force established by a magnet pole4 ,the attractions and repulsions exercised by such a field follow the course of the electro- magnetic lines of force4 7,see also ,field of ,force47 ,thus the tendency of a polarized needle attracted or repelled is to follow1 always keeping tangential to curved lines1 the direction of the lines of force1 however sweeping they may be4 ,the direction of magnetic lines of force is assumed to be the direction in which a positive pole is repelled or a negative one attracted2 in other words1 from the north pole of a magnet to its south pole in the outer circuit4 ,the direction of lines of force at any point1 and the intensity or strength of the field at that point1 express the conditions there4 ,the intensity may bc expressed in terms of that which a unit pole at unit distance would produce4 ,this intensity as unitary it has been proposed to term a ,gauss4 7,see ,weber47 ,the direction of the lines of force in a magnetic field are shown by the time-honored experiment of sprinkling filings of iron upon a sheet of paper held over a magnet pole or poles4 ,they arrange themselves1 if the paper is tapped1 in more or less curved lines tending to reach from one pole of the magnet to the other4 ,many figures may be produced by different conditions4 ,two near poles of like name produce lines of force which repel each other4 7,see ,magnetic ,curves47 ,a magnetic and an electro-magnetic field are identical in all essential respects2 the magnetic field may be regarded as a special form of the electro-magnetic field1 but only special as regards its production and its defined north and south polar regions4 ,synonyms--,magnetic ,spin 7not much used74 ,magnetic ,field1 ,uniform4 ,a field of identical strength in all parts1 such as the earth's magnetic field4 ,if artificially produced1 which can only be approximately done1 it implies large cross-section of magnet pole in proportion to the length of the magnetic needle affected by it1 which is used in determining its uniformity4 ,magnetic ,figures4 ,the figures produced by iron filings upon paper or glass held near magnetic poles4 ,by these figures the direction of lines of force is approximately given1 and a species of map of the field is shown4 7,see ,magnetic ,field of ,force--,magnetic ,curves47 ,magnetic ,filament4 ,the successive rows of polarized molecules assumed to exist in magnetized iron4 ,each molecule represents an infinitely small magnet1 and its north pole points to the south pole of the next molecule4 ,such a string or row is a theoretical conception based on the idea that the molecules in a magnet are all swung in to parallelism in the magnetizing process4 ,a magnetic filament may be termed the longitudinal element of a magnet4 7,see ,magnetism1 ,hughes' ,theory of47 ,transcriber's note3 ,this description parallels the modern notion of electron spin as the basis of magnetism in materials4 ,magnetic ,fluids4 ,a two-fluid theory of magnetism has been evolved1 analogous to the two-fluid theory of electricity4 ,it assumes north fluid or red magnetism and a south fluid or blue magnetism4 ,each magnetism is supposed to predominate at its own pole and to attract its opposite4 ,before magnetization the fluids are supposed to neutralize each other about each molecule2 magnetization is assumed to separate them1 accumulating quantities of them at the poles4 ,magnetic ,flux4 ,magnetic induction2 the number of lines of force that pass through a magnetic circuit4 ,synonym--,magnetic ,flow4 #cdf ,,standard ,,electrical ,,dictionary4 ,magnetic ,force4 ,the forces of attraction and repulsion exercised by a magnet4 ,by ,ampere's theory it is identical with the forces of attraction and repulsion of electric currents4 ,magnetic ,friction4 ,the damping effect produced on the movements of a mass of metal by proximity to a magnet2 the phenomenon illustrated in ,arago's wheel1 q4 v4 ,when a mass of metal moves in the vicinity of a magnet it cuts the lines of force emanating from its poles1 thereby producing currents in its mass2 as the production of these currents absorbs energy a damping effect is produced upon the movements of the mass4 ,magnetic ,gear4 ,friction gear in which electro-magnetic adherence is employed to draw the wheels together4 7,see ,adherence1 ,electro-magnetic--,electro-magnetic ,friction ,gear47 ,magnetic ,inclination4 ,the inclination from the horizontal of a magnetic needle placed in the magnetic meridian4 7,see ,magnetic ,element--,inclination ,map47 ,synonym--,magnetic ,dip4 ,magnetic ,induction4 ,the force of magnetization within an induced magnet4 ,it is in part due to the action of the surrounding particles of polarized material2 in part to the magnetic field4 7,see ,magnetic ,induction1 ,coefficient of47 ,in a more general way it is the action of a magnet upon bodies in its field of force4 ,in some cases the magnetism induced causes the north pole of the induced magnet to place itself as far as possible from the north pole of the inducing magnet and the same for the south poles4 ,such substances are called paramagnetic or ferromagnetic4 ,they lie parallel or tangential to the lines of force4 ,in other cases the bodies lie at right angles or normal to the lines of force4 ,such bodies are called diamagnetic4 ,some bodies are crystalline or not homogeneous in structure1 and in them the lines of magnetic induction may take irregular or eccentric paths4 7,see ,a,eolotropic47 ,synonym--,magnetic ,influence4 ,magnetic ,induction1 ,apparent ,coefficient of4 ,the apparent permeability of a paramagnetic body as affected by the presence of ,foucault currents in the material itself4 ,these currents act exactly as do the currents in the coils surrounding the cores of electro-magnets4 ,they produce lines of force which may exhaust the permeability of the iron1 or may1 if in an opposite direction1 add to its apparent permeability4 ,magnetic ,induction1 ,coefficient of4 ,the number1 obtained by dividing the magnetization of a body1 expressed in lines of force produced in it1 by the magnetizing force which has produced such magnetization1 expressed in lines of force producible by the force in question in air4 ,it always exceeds unity for iron1 nickel and cobalt4 ,it is also obtained by multiplying the coefficient of induced magnetization by #d ,,pi 7#d 99 #c4adaei7 and adding #a4 7,see ,magnetic ,susceptibility--,magnetization1 ,coefficient of ,induced47 #cdg ,,standard ,,electrical ,,dictionary4 ,the coefficient of magnetic induction varies with the material of the induced mass1 and varies with the intensity of the magnetizing force4 ,this variation is due to the fact that as the induced magnetism in a body increases1 the magnetizing force required to maintain such induction1 increases in a more rapid ratio4 ,the coefficient of magnetic induction is the same as magnetic permeability1 and in a certain sense is the analogue of conductivity4 ,it is also termed the multiplying power of the body or core magnetized4 ,it is the coefficient of induced magnetization 7see ,magnetization1 ,coefficient of ,induced7 referred to a mass of matter4 ,for diamagnetic bodies the coefficient has a negative sign2 for paramagnetic bodies it has a positive sign4 ,synonyms--,permeability--,multiplying ,power--,magnetic ,inductive ,capacity4 ,magnetic ,induction1 ,dynamic4 ,the induction produced by a magnetic field which moves with respect to a body1 or where the body if moving moves at a different rate1 or where the body moves and the field is stationary4 ,in the case where both move1 part of the induction may be dynamic and part static4 7,see ,magnetic ,induction1 ,static47 ,magnetic ,induction1 ,static4 ,magnetic induction produced by a stationary field acting upon a stationary body4 ,magnetic ,induction1 ,tube of4 ,an approximate cylinder or frustrum of a cone whose sides are formed of lines of magnetic induction4 7,see ,magnetic ,induction1 ,lines of47 ,the term tube is very curiously applied in this case1 because the element or portion of a magnetic field thus designated is in no sense hollow or tubular4 ,magnetic ,inertia4 ,a sensible time is required to magnetize iron1 or for it to part with its magnetism1 however soft it may be4 ,this is due to its magnetic inertia and is termed the lag4 ,permanent or residual magnetism is a phase of it4 ,it is analogous to self-induction of an electric circuit1 or to the residual capacity of a dielectric4 ,magnetic ,insulation4 ,only approximate insulation of magnetism is possible4 ,there is no perfect insulator4 ,the best ones are only #aj1jjj times less permeable than iron4 ,hence lines of force find their way through air and all other substance1 being simply crowded together more in paths of iron or other paramagnetic substance4 #cdh ,,standard ,,electrical ,,dictionary4 ,magnetic ,intensity4 ,the intensity of the magnetization of a body4 ,it is measured by the magnetic lines of force passing through a unit area of the body1 such area being at right angles to the direction of the lines of force4 ,magnetic ,lag4 ,in magnetism the tendency of hard iron or steel especially to take up magnetism slowly1 and to part with it slowly4 7,see ,magnetic ,inertia47 ,the lag affects the action of a dynamo1 and is a minor cause of those necessitating the lead of the brushes4 ,synonym--,magnetic ,retardation4 ,magnetic ,latitude4 ,latitude referred to the magnetic equator and isoclinic lines4 ,magnetic ,leakage4 ,the lines of force in a field magnet which pass through the air and not through the armature are useless and represent a waste of field4 ,such lines constitute magnetic leakage4 ,magnetic ,limit4 ,the temperature beyond which a paramagnetic metal cannot be magnetized4 ,the magnetic limit of iron is from a red to a white heat2 of cobalt1 far beyond a white heat2 of chromium1 below a red heat2 of nickel at about #cej ,c4 7#ffb;,f47 of manganese1 from #ae ,c4 to #bj ,c4 7#ei to #fh ,f47 ,magnetic ,lines of ,force4 ,lines of force indicating the distribution of magnetic force1 which is due presumably to whirls of the ether4 ,a wire or conductor through which a current is passing is surrounded by an electro-magnetic field of force1 q4 v41 whose lines of force form circles surrounding the conductor in question4 ,a magnet marks the existence of a similar electro-magnetic field of force whose lines form circuits comprising part of and in some places all of the body of the magnet1 and which are completed through the air or any surrounding paramagnetic or diamagnetic body4 ,they may be thought of as formed by the ,amprian sheet of current1 and analogous to those just mentioned as surrounding a conductor4 ,fig4 #bbc4 ,,magnetic ,,lines ,,of ,,force1 ,,direction ,,of4 ,a magnetic line of force may be thought of as a set of vortices or whirls1 parallel to each other1 and strung along the line of force which is the locus of their centres4 ,if as many lines are drawn per square centimeter as there are dynes 7per unit pole7 of force at the point in question1 each such line will be a unitary c4 g4 s4 line of force4 #cdi ,,standard ,,electrical ,,dictionary4 ,magnetic ,mass4 ,a term for a quantity of magnetism4 ,unit mass is the quantity which at unit distance exercises unit force4 ,magnetic ,matter4 ,imaginary matter assumed as a cause of magnetism4 ,two kinds1 one positive and one negative1 may be assumed as in the two fluid theory of electricity1 or only one kind1 as in the single fluid theory of electricity4 ,various theories of magnetic matter have been presented whose value is only in their convenience4 ,transcriber's note3 ,see magnet and ,edward ,purcell's explanation of magnetism using general relativity4 ,magnetic ,memory4 ,the property of retaining magnetism2 coercive force2 magnetic inertia2 residual magnetism4 ,transcriber's note3 ,small ferrite magnetic donuts were used as computer main memory from #aiej to #aigj4 ,magnetic ,meridian4 ,a line formed on the earth's surface by the intersection therewith of a plane passing through the magnetic axis4 ,it is a line determined by the direction of the compass needle4 ,the meridians constantly change in direction and correspond in a general way to the geographical meridians4 ,magnetic ,moment4 ,the statical couple with which a magnet would be acted on by a uniform magnetic field of unit intensity if placed with its magnetic axis at right angles to the lines of force of the field4 7,emtage47 ,a uniformly and longitudinally magnetized bar has a magnetic moment equal to the product of its length by the strength of its positive pole4 ,magnetic ,needle4 ,a magnet with a cup or small depression at its centre and poised upon a sharp pin so as to be free to rotate or oscillate in a horizontal plane4 ,the cup is often made of agate4 ,left free to take any position1 it places its magnetic axis in the magnetic meridian4 ,magnetic ,parallels4 ,lines roughly parallel to the magnetic equator on all parts of each of which the dip of the magnetic needle is the same2 also called ,isoclinic ,lines4 ,these lines mark the places of the intersection of equipotential surfaces with the earth's surface4 ,they are not true circles1 and near the poles are irregular ellipses2 the magnet there points toward their centres of curvature4 ,they correspond in a general way with the ,geographical ,parallels of ,latitude4 ,magnetic ,permeability4 ,the specific susceptibility of any substance1 existing in a mass1 for magnetic induction4 7,see ,magnetic ,induction1 ,coefficient of1 synonym for ,magnetic ,permeability and ,magnetization1 ,coefficient of ,induced47 ,synonyms--,magnetic ,inductive ,capacity--,multiplying ,power--,coefficient of ,magnetic ,induction4 #cej ,,standard ,,electrical ,,dictionary4 ,magnetic ,perturbations4 ,irregular disturbances of the terrestrial magnetism1 as by the aurora and in electric storms4 ,magnetic ,poles4 ,the points where the equipotential surfaces of the terrestrial field of force graze the earth's surface2 the points toward which the north or south poles of the magnetic needle is attracted4 ,over a magnetic pole the magnetic needle tends to stand in a vertical position4 ,there are two poles1 ,arctic or negative1 and ,antarctic or positive4 ,magnetic needles surrounding them do not necessarily point toward them1 as they point to the centres of curvature of their respective magnetic parallels4 ,the poles constantly change in position4 ,the line joining them does not coincide with anything which may be termed the magnetic axis of the earth4 ,magnetic ,poles1 ,false4 ,poles on the earth's surface other than the two regular magnetic poles4 ,there seem by observation to be several such poles1 while analogy would limit true magnetic poles to two in number4 ,magnetic ,potential4 ,the potential at any point of a magnetic field is the work which would be done by the magnetic forces of the field upon a positive unit of magnetism as it moves from that point to an infinite distance4 7,emtage47 ,magnetic ,proof ,piece4 ,a piece of iron used for testing magnets and the distribution of magnetism in bars1 by suspending or supporting above or near the magnet1 by detaching after adherence1 and in other ways4 ,magnetic ,proof ,plane4 ,an exploring coil used for testing the distribution of magnetism4 ,it is connected in circuit with a galvanometer1 and exposed to alternation of current1 or to other disturbing action produced by the magnet or field under examination4 ,this affects the galvanometer1 and from its movements the current produced in the coil1 and thence the magnetic induction to which it was exposed1 are calculated4 ,synonym--,exploring ,coil4 ,magnetic ,quantity4 ,the magnetism possessed by a body2 it is proportional to the action of similar poles upon each other1 or to the field produced by the pole in question4 ,it is also called the strength of a pole4 ,the force exercised by two similar poles upon each other varies with their product and inversely with the square of the distance separating them2 or it may be expressed thus 7m 99 m7 _/ 7,l#b74 ,this is a force1 and the dimensions of a force are ,,ml_/7,t#b74 ,therefore1 7m#b7_/7,l#b7 ,,ml_/7,t#b7 or m 7,m4#e7997,l#a4e7_/,t4 #cea ,,standard ,,electrical ,,dictionary4 ,magnetic ,reluctance4 ,the reciprocal of permeance2 magnetic resistance2 the relative resistance to the passage of lines of force offered by different substances4 ,the idea is derived from treating the magnetic circuit like an electric one1 and basing its action on magneto-motive force acting through a circuit possessing magnetic reluctance4 ,magnetic ,reluctivity4 ,the reciprocal of magnetic permeability1 q4 v4 ,synonym--,magnetic ,resistance4 ,magnetic ,retentivity4 ,the property of steel or hard iron by which it slowly takes up and slowly parts with a magnetic condition--traditionally 7,daniell7 called coercitive force4 ,magnetic ,rotary ,polarization4 ,if a plane polarized beam of light is sent through a transparent medium in a magnetic field its plane of polarization is rotated1 and this phenomenon is denoted as above4 7,compare ,refraction1 ,electric1 and see ,electro-magnetic ,stress47 ,this has been made the basis of a method for measuring current4 ,a field of force varies with the current2 the polarization produced by such field is therefore proportional to the current4 7,becquerel ,rayleigh47 ,a plane polarized beam of light passing through the transparent medium in the magnetic field by the retardation or acceleration of one of its circular components has its plane of polarization rotated as described4 ,the direction of the lines of force and the nature of the medium determine the sense of the rotation2 the amount depends upon the intensity of the field resolved in the direction of the ray1 and on the thickness and nature of the medium4 ,magnetic ,saturation4 ,the maximum magnetic force which can be permanently imparted to a steel bar4 ,a bar may be magnetized beyond this point1 but soon sinks to it4 ,the magnetism produced in a bar is prevented from depolarization by the retentivity or coercive force of the bar4 ,the higher the degree of magnetization the greater the tendency to depolarization4 ,it is also defined as the maximum intensity of magnetism produced in a paramagnetic substance by a magnetic field as far as affected by the permeability of the substance in question4 ,the more lines of force passed through such a substance the lower is its residual permeability4 ,it is assumed that this becomes zero after a certain point1 and then the point of saturation is reached4 ,after this point is reached the addition of any lines of force is referred entirely to the field and not at all to the permeability of the substance4 ,but such a zero is only definable approximately4 ,magnetic ,screen4 ,a box or case of soft iron1 as thick as practicable1 for protecting bodies within it from the action of a magnetic field4 ,the lines of force to a great extent keep within the metal of the box on account of its permeability1 and but a comparatively few of them cross the space within it4 ,such screens are used to prevent watches from being magnetized1 and are a part of ,sir ,william ,thomson's ,marine galvanometer4 ,a magnetic screen may be a sphere1 an infinite or very large plane1 or of the shape of any equipotential surface4 ,synonym--,magnetic ,shield4 #ceb ,,standard ,,electrical ,,dictionary4 ,magnetic ,self-induction4 ,the cause of a magnet weakening is on account of this quality1 which is due to the direction of the lines of force within a magnet from the positive towards the negative pole4 ,a magnet thus tends to repel its own magnetism and to weaken itself by self-induction4 7,daniell47 ,magnetic ,separator4 ,an apparatus for separating magnetic substances from mixtures4 ,such separators depend on the action of electro-magnets4 ,in one form the material falls upon an iron drum1 magnetized by coils4 ,any magnetic substance adheres to the drum and is thereby separated4 ,they are used by porcelain makers for withdrawing iron particles from clay1 by machinists to separate iron filings and chips from brass1 and for similar purposes4 ,fig4 #bbd4 ,,magnetic ,,separator4 ,magnetic ,shell4 ,a theoretical conception of a cause of a magnetic field or of a distribution of magnetism4 ,if we imagine a quantity of very short magnets arranged in contact with their like poles all pointing in the same direction so as to make a metal sheet1 we have a magnetic shell4 ,its magnetic moment is equal to the sum of the magnetic moment of all its parts4 ,if the shell is of uniform strength the magnetic moment of a unit area gives the strength of the shell2 it is equal to the magnetic quantity per unit of area1 multiplied by the thickness of the shell4 ,if its strength is uniform throughout a magnetic shell is called simple2 if its strength varies it is termed complex4 ,emtage thus defines it3 ,a magnetic shell is an indefinitely thin sheet magnetized everywhere in the direction normal to itself4 ,magnetic ,shell1 ,strength of4 ,the magnetic quantity per unit of area of the shell multiplied by the thickness of the shell4 #cec ,,standard ,,electrical ,,dictionary4 ,magnetic ,shield4 ,in general a magnetic screen1 q4 v4 ,sometimes a strong local field is made to act as a shield1 by its predominance overcoming any local or terrestrial field to which the needle to be protected may be exposed4 ,magnetic ,shunt4 ,the conception of a magnetic circuit being formed1 the shunt is a corollary of the theory4 ,it is any piece of iron which connects points of a magnet differing in polarity1 so as to divert part of the lines of force from the armature or yoke4 ,the shunt is especially applicable in the case of horseshoe magnets4 ,thus a bar of iron placed across from limb to limb a short distance back from the poles would act as a shunt to the armature and would divert to itself part of the lines of force which would otherwise go through the armature and would weaken the attraction of the magnet for the latter4 ,in dynamos a bar of iron used as a magnetic shunt has been used to diminish the lines of force going through the armature and hence to weaken the field and diminish the electro-motive force4 ,by moving the shunt nearer or further from the poles the dynamo is regulated4 ,in the cut the projections between the yoke and poles of the magnet shown act as a shunt to the yoke1 taking some lines of force therefrom4 ,fig4 #bbe4 ,,magnetic ,,shunt4 ,magnetic ,storms4 ,terrestrial magnetic disturbances sometimes covering very wide areas1 and affecting the magnetic declination and inclination4 ,one such disturbance was felt simultaneously at ,toronto1 ,canada1 the ,cape of ,good ,hope1 ,prague and ,van ,diemen's ,land4 7,sabine47 #ced ,,standard ,,electrical ,,dictionary4 ,magnetic ,strain4 ,the strain produced by magnetic lines of force in substances exposed to their action4 ,it is observed in substances placed between the poles of a strong electro-magnet1 and evinces itself in the alteration of the optical properties of transparent substances4 ,magnetic ,stress4 ,the stress produced by magnetic lines of force on substances through which they pass1 evidenced in alteration of the optical properties of transparent bodies thus treated4 ,magnetic ,susceptibility4 ,the specific intrinsic susceptibility of any material for magnetic induction4 ,it refers to the particle of matter1 and not to the mass1 as in the latter its own particles react on each other and bring about what is termed permeability1 q4 v4 7,see also ,magnetization1 ,coefficient of ,induced1 and ,magnetic ,induction1 ,coefficient of47 ,synonym--,coefficient of ,induced ,magnetization4 ,magnetic ,tick4 ,when a bar of iron is suddenly magnetized or demagnetized it emits a slight sound1 called the ,page sound1 or the magnetic tick4 ,this has been utilized in a telephone by ,reiss4 ,the telephone will receive sound1 but is very weak4 ,it consists of a bar surrounded with a coil of insulated wire4 ,variations in current produce sounds1 which may be articulate if the currents are produced by a telephonic transmitter4 ,magnetic ,twist4 ,a bar of iron held in the magnetic meridian and pointing to the pole and twisted becomes to some extent permanently magnetized4 ,conversely a bar when magnetized seems to have a twist set up in it4 ,the latter is magnetic twist4 ,magnetic ,variations4 ,changes in the value of magnetic declination or inclination4 7,see ,magnetic ,elements47 ,magnetism1 ,ampre's ,theory of4 ,a theory accounting for magnetic phenomena by assuming the existence of currents circulating around the molecules of permanent magnets4 ,if such currents so circulate and all in the same direction1 the result is the same as if the body of the magnet was enveloped in currents representing those of an electro-magnet or solenoid4 ,this is because in the interior the current around one molecule would counteract the current around its neighboring ones in part1 so that the only virtual currents left would be represented by those on the outer surfaces of the outer shell of molecules1 and these virtually resolve themselves into one general current sheet1 surrounding the magnet and coinciding with its surface4 ,the theory assumes that such currents permanently circulate around the molecules of paramagnetic substances4 ,under ordinary conditions there is no coincidence in their direction and no resultant current is produced4 ,when magnetized or polarized the molecules are brought into order1 so that the direction of their current coincides and the body becomes a magnet4 #cee ,,standard ,,electrical ,,dictionary4 ,fig4 #bbf4 ,,amp,,rian ,,currents ,,in ,,magnets4 ,at the north pole of the magnet the direction of the ,amprian currents is the reverse of that of a watch when the observer faces the pole2 the reverse obtains for the south pole4 ,the attraction of opposite and repulsion of similar poles is explained by the actions of the ,amprian currents upon each other4 ,if north and south pole are placed together these currents will coincide in direction and hence will attract each other4 ,if two like poles are put together the currents will have opposite directions and will repel each other4 ,no energy is supposed to be required to maintain currents around or in a single molecule4 ,fig4 #bbg4 ,,north ,,and ,,south ,,poles ,,of ,a ,,magnet ,,showing ,,direction ,,of ,,amp,,rian ,,currents4 ,magnetism1 ,blue4 ,a term arising from the two fluid theory of magnetism2 the magnetism of the south pole of a magnet4 7,see ,magnetic ,fluids47 ,the magnetism of the north pole is termed red magnetism4 ,both terms originated presumably in the painting of magnets1 and are little used4 ,synonym--,south ,magnetic ,fluid4 #cef ,,standard ,,electrical ,,dictionary4 ,magnetism1 ,components of ,earth's4 ,the magnetic force of the earth acts in the plane of the magnetic meridian and in direction generally lies oblique to the plane of the horizon4 ,it can be resolved into two components1 one vertical1 which has no directive effect upon the magnetic needle1 the other horizontal1 which represents the directive element for the usual compass needle4 ,for the dipping needle1 q4 v41 the vertical component is the only active one4 ,a magnetic needle mounted on a universal joint at its centre of gravity would be acted on by both components4 ,magnetism1 ,creeping of4 ,the gradual increase of magnetism when a magnetic force is applied with absolute steadiness to a piece of iron4 ,it is a form of magnetic lag4 ,it may last for half an hour and involve an increase of several per cent4 of the total magnetism4 ,synonym--,viscous ,hysteresis4 ,magnet1 ,iron ,clad4 ,a magnet with a casing of iron connected at one end to the core4 ,the term is generally applied to electromagnets of this form4 ,synonyms--,tubular ,magnet--,jacketed ,magnet4 ,magnetism1 ,decay of4 ,the gradual loss of magnetism by permanent magnets1 due to accidental shocks1 changes of temperature1 slow spontaneous annealing of the iron and other similar causes4 ,magnetism1 ,discharge of4 ,the loosing of magnetization4 ,thus in a shunt-wound dynamo there is a critical resistance for the outer circuit1 below which the field ceases to be magnetized1 as enough current ceases to be shunted into it to magnetize it4 ,the machine is said to unbuild itself1 and a discharge of magnetism occurs from the field magnet4 ,magnetism1 ,ewing's ,theory of4 ,ewing found by a model consisting of a number of pivoted magnetic needles that the observed phenomena of magnetization could be represented thereby4 ,thus there would be no need of assuming internal frictional forces of ,maxwell1 nor the closed rings or chains of ,hughes4 ,the theory retains the notion1 however1 of paramagnetic matter1 consisting of an assemblage of molecular magnets4 ,the loss of energy by hysteresis is represented in the model by the energy lost by the needles in beating against the air4 #ceg ,,standard ,,electrical ,,dictionary4 ,magnetism1 ,free4 ,the magnetism or magnetic field outside of a magnetic circuit4 ,it is due to escape of lines of force and to the magnetic leakage through the air4 ,the lines of force are never1 under the most favorable circumstances1 confined to the metallic circuit of the magnet and armature4 ,in a simple magnet without armature all the lines of force have to follow an air path1 and the field is at its strongest4 ,as the magnetism is strongest at the surface near the poles1 the term is sometimes understood as applying to the surface attraction4 ,in such case it is defined as the distribution1 on a magnetized bar or mass1 of magnetic lines of force as they emerge from its surface4 ,synonym--,surface ,magnetization4 ,magnetism1 ,hughes' ,theory of4 ,a theory accounting for magnetic phenomena by assuming that each molecule is a magnet1 and that in a polarized or magnetized body they are all arranged with their poles in the same direction1 while in an unmagnetized body their poles1 alternating in direction1 neutralize each other4 ,magnetization consists in a partial rotation of the molecules so as to make them agree in position1 thus1 as a resultant developing north and south poles at the ends of the bar4 ,the theory is in a certain sense simpler than ,ampere's theory1 but is not so generally adopted4 ,magnetism1 ,lamellar ,distribution of4 ,the distribution of magnetism in thin and uniform or simple magnetic shells1 q4 v4 ,a given distribution is termed lamellar if the substance in which it exists can be divided into simple magnetic shells1 which either form closed surfaces1 or have their edges in the surface of the substance4 ,in lamellar distribution the polar area is very large compared with the distance between opposite poles4 ,magnetism of ,gases4 ,faraday experimented on this point by coloring gases with a little vapor of iodine or other colored gas1 and letting them flow between the two poles of a powerful electromagnet4 ,in this way he found some are repelled1 some attracted1 and in the case of oxygen1 it is attracted at one temperature and repelled at another4 ,at ordinary temperatures a cubic yard of oxygen possesses the magnetism of #e4e grains of iron and when liquefied it is strongly attracted4 ,magnetism or ,magnetization1 ,temporary4 ,when a mass of iron is magnetized by a current1 when the current ceases the portion of its magnetism which disappears is the temporary magnetism2 the portion retained is the residual or permanent magnetism4 ,magnetism1 ,red4 ,a term arising from the two fluid theory of magnetism2 the magnetism of the north pole of a magnet4 7,see ,magnetic ,fluids47 ,the magnetism of the south pole is termed blue magnetism4 ,both terms originated in the painting of magnets4 ,they are but little used4 ,synonym--,north ,magnetic ,fluid4 #ceh ,,standard ,,electrical ,,dictionary4 ,magnetic ,remanence4 ,the residual magnetism left in a bar of steel or other paramagnetic material after the application of a powerful magnet4 ,it is distinguished from coercive force1 as the latter is the amount of negative magnetizing or of demagnetizing force required to reduce the remanent magnetism to zero4 ,synonym--,remanence--,residual ,magnetism4 ,magnetism1 ,solenoidal ,distribution of4 ,the distribution of magnetism in such a way that the poles are very far apart in proportion to their area4 ,the magnetization of a long thin bar of steel illustrates solenoidal distribution4 ,magnetism ,sub-permanent4 ,the magnetism of a paramagnetic substance which presents a considerable degree of permanency1 but which gradually disappears1 leaving the permanent magnetism present4 ,it is noticeable in iron or steel ships whose magnetism gradually reduced in quantity1 eventually becomes fully permanent4 ,magnetism1 ,weber's ,theory of4 ,the molecules of a magnetizable material by this theory are supposed to be magnets with their poles lying in every direction1 and hence neutralizing each other4 ,by magnetization these are supposed to be turned with their similar poles in the same direction1 and their axis parallel1 hence acting like a group of magnets4 ,it is practically identical with ,hughes' theory4 ,magnetism1 ,terrestrial4 ,the magnetism of the earth4 7,see ,magnetic ,elements47 ,fig4 #bbh4 ,,magnetization ,,by ,,double ,,touch4 ,magnetization by ,double ,touch4 ,the process of magnetizing a steel bar by simultaneously stroking it with two poles of a horseshoe magnet or with two opposite poles of two bar magnets4 ,the poles must be close but not touching4 ,a block of wood may be placed between the ends if single magnets are used4 ,the poles are placed on the middle of the bar and carried back and forth to one end1 then to the other1 and so on1 ending at the middle of the bar in such direction as to give each end the same number of strokes4 ,the poles must be close together or consequent poles will be produced4 ,if bar magnets are used they may be held inclined at an angle of #ae to #bj with the horizontal bar to be magnetized4 ,the ends of the latter may rest on poles of two other magnets1 each end on a pole of the same name as that of the magnetizing magnet on its side4 7,see ,magnetization1 ,hoffer's ,method47 #cei ,,standard ,,electrical ,,dictionary4 ,magnetization by ,separate ,touch4 ,a method of magnetization4 ,two magnets are used4 ,held in an inclined position two opposite poles are touched to the bar near its centre1 and are drawn off to the two ends4 ,they are returned through the air and the process is repeated4 ,magnetization by ,single ,touch4 ,a method of polarizing or magnetizing steel bars1 by stroking them always in one direction with one pole of a magnet1 returning it through the air4 ,the stroking is best done on both sides4 ,the stroking may begin at one end and end at the other1 or it may be commenced in the center of the bar and be carried to one end with one pole1 and the same done for the other half with the other pole4 ,magnetization by the ,earth4 ,the earth imparts magnetism to iron masses4 ,if a rod of steel is held parallel to the inclination and in the magnetic meridian it exhibits polarity1 which by jarring or hammering1 can be made to some extent permanent4 ,a piece of soft iron held vertically1 or still better in the line of the dip as above1 and which is twisted when in that position1 becomes magnetized with some degree of permanence4 ,many other instances are cited1 such as fire-irons1 lamp-posts1 iron gates1 lathe turnings1 all of which often exhibit polarity1 having been magnetized by the earth's field4 ,transcriber's note3 ,the earth's magnetic field is believed to originate it electric currents in the moving molten core4 ,magnetization1 ,coefficient of ,induced4 ,the coefficient 7q4 v47 expressing the relation between the specific intensity of magnetization of a particle and the magnetizing force4 ,the magnetizing force is measured by the lines of force it can produce in a field of air4 ,the coefficient of induced magnetization is the factor by which the intensity of a magnetizing field must be multiplied to produce the magnetization imparted by it to a particle of any substance4 ,this coefficient varies for different substances1 and is also called magnetic susceptibility4 ,it is distinguished from permeability as referring only to a particle isolated from influence of a mass of surrounding particles of its own kind4 ,it is definable as the intensity of the magnetization assumed by an exceedingly long and exceedingly thin bar placed in a unit field4 ,if a mass of metal were placed in such a field all its particles would become affected and within the mass no unit field could exist4 ,hence magnetic susceptibility 7another name for this coefficient7 does not apply to the case of large cores of electro-magnets and dynamo-armatures1 but is really a theoretical rather than a practical figure4 ,the sign of the coefficient of diamagnetic bodies is negative2 of paramagnetic bodies is positive4 ,synonym--,magnetic ,susceptibility4 #cfj ,,standard ,,electrical ,,dictionary4 ,magnetization1 ,cycle of4 ,a cycle of positive or of positive and negative magnetization represents the application of a magnetizing force beginning at a fixed value1 generally zero1 rising to a maximum1 or to a value of maximum distance from the initial and then returning to the original basis4 ,it is virtually a full wave of magnetization and may extend on both sides of a zero line giving positive and negative values4 ,cycles of magnetization apply especially to transformers and other apparatus of that character used with the alternating current system4 ,magnetization1 ,hoffer's ,method4 ,for horseshoe bars an armature is placed against the poles of the magnet bar to be treated4 ,the poles of a strong horseshoe magnet are stroked over it from poles to bend and returned through the air1 or vice versa4 ,in the first case the poles will be the same as those of the inducing magnet2 in the second case they will be opposite4 ,a maximum effect is produced in ten strokes4 ,the stroking should be applied to both sides4 ,an electro-magnet may be used as inducer as shown1 but an armature should be used2 in the cut it is omitted4 ,fig4 #bbi4 ,,magnetizing ,a ,,horseshoe ,,magnet4 ,magnetization1 ,intensity of4 ,the amount of magnetism induced in or present in a body4 ,it is expressed in ,magnetic ,lines of ,force1 q4 v41 per cross-sectional area4 ,magnetization1 ,isthmus ,method of4 ,a method used by ,ewing in a research on the magnetization of iron in very strong fields4 ,he used samples of iron turned down in the centre to a narrow neck1 and thus concentrated the lines of force greatly4 ,magnetization1 ,elias' ,method4 ,the bar to be magnetized is surrounded by a magnetizing coil1 q4 v4 ,a strong current is passed through it1 and the coil is moved back and forth a few times4 ,magnetization1 ,jacobi's ,method4 ,for horseshoe bars4 ,the bar is placed with its poles against those of a horseshoe magnet4 ,a bar of soft iron1 long enough to reach from outside to outside of the legs1 is laid across near the junction and is drawn along towards the bend of the new bar and away from it4 ,this is repeated a few times on both sides4 #cfa ,,standard ,,electrical ,,dictionary4 ,magnetization1 ,limit of4 ,as the induction of magnetizing force increases1 magnetization of paramagnetic metals tends towards a limit1 the increase in magnetization being continually less and less as the metal becomes more highly magnetized4 ,in diamagnetic substances no limit is discernible4 ,synonym--,maximum ,magnetization4 ,magnetization1 ,specific4 ,the magnetic moment per gram of a substance4 ,magnet-keeper4 ,a bar of iron connecting the two poles of a permanent magnet4 ,often the same bar serves as armature and keeper4 ,magnet1 ,lamination of4 ,it is advantageous to make magnets of laminated construction1 or of thin plates of steel4 ,the thin metal can be better tempered or hardened than thick metal4 ,a slight separation of the plates is advantageous from some points of view4 ,if in actual contact there is some danger that the weaker members will have their polarity reversed by the stronger ones4 ,this is counteracted to some extent by separation4 ,magnet1 ,long ,coil4 ,a high resistance electro-magnet2 one whose coil is of thin wire of considerable length4 ,magnet1 ,natural4 ,the lodestone1 q4 v42 a variety of magnetite or magnetic oxide of iron1 exhibiting permanent magnetism1 attracting iron1 and possessing north and south poles4 ,magnet1 ,neutral ,line of4 ,a line at right angles to the magnetic axis of a magnet1 q4v41 and nearly or quite at the centre1 so situated with reference to the poles on either end that it marks the locus of no polarity4 ,it has been called the equator of the magnet4 ,it is defined by the intersection of the plane of no magnetism with the surface of the bar4 ,synonym--,magnetic ,equator4 ,magnet1 ,normal4 ,a bar or compound bar magnet1 magnetized to such an extent that the curves of the lines of force run into each other in the middle1 is thus termed by ,jamin4 ,magneto4 ,abbreviation for ,magneto-electric ,generator4 7,see ,magneto-electric ,generator47 ,magneto ,call ,bell4 ,a call operated by current from a magneto-electric generator4 ,it is very generally used in telephone systems4 #cfb ,,standard ,,electrical ,,dictionary4 ,magneto-electric4 adj4 ,relating to induced electric effects due to the cutting of true magnetic lines of force by1 or equivalent action of or upon a conductor4 ,these effects are identical with electro-magnetic effects and are only distinguished from them by the field being due to a permanent magnet instead of an electromagnet4 ,magneto-electric ,brake4 ,a device for bringing to rest an oscillating galvanometer needle4 ,it consists essentially of a coil in circuit with a key and with the galvanometer4 ,on opening the circuit an inverse current is established by induction1 tending to bring the needle to rest4 ,magneto-electric ,generator4 ,a current generator operating by maintaining a potential difference at its terminals1 by reactions in a field of force1 which field is established by a permanent magnet4 ,the cut1 ,fig4 #bcj1 shows the general principle of construction of a direct current generator4 ,the armature is rotated between the poles of a permanent magnet4 ,any of the regular types of dynamo armature can be used4 ,from its commutator the current is taken by brushes4 ,fig4 #bcj4 ,,magneto-,,electric ,,generator4 ,fig4 #bca4 ,,magneto-,,electric ,,generator4 #cfc ,,standard ,,electrical ,,dictionary4 ,the cut1 ,fig4 #bca1 shows an alternating current machine4 ,in it a pair of bobbins1 wound in series1 and both either right-handed or left-handed1 are rotated between permanent magnet poles4 ,the current may be taken off by two brushes bearing on two collecting rings on the axis of the bobbins1 the ends of the wire being connected thereto4 ,or if a shocking current is desired1 one of the brushes or springs may strike a series of pins forming virtually a broken or interrupted collecting ring4 ,this gives a current for medical purposes4 ,synonyms--,magneto-dynamo--,magneto-ele ctric ,machine4 ,magnetograph4 ,an apparatus for recording variations in magnetic elements4 ,one type includes a magnetic needle to which a concave mirror is attached4 ,the light ray from the mirror is reflected upon sensitized paper where its movements are photographically reproduced4 ,the movements of the spot are due to the movements of the needle and act as the record of the same4 ,magneto-,inductor4 ,an instrument for use with a ballistic galvanometer to reproduce a definite current impulse4 ,two magnets are fastened together in one straight line1 the north poles almost touching4 ,this is mounted at the end of a rod like a pendulum1 the axis of the magnets transverse to the rod4 ,the magnets are carried by a frame and oscillate at the end of the rod1 back and forth within a fixed coil1 which is one-half the length of the double magnet4 ,a bob is attached to the bottom of the frame by which the whole can be swung4 ,as the magnets are of fixed value1 their time of oscillation constant1 and the coil fixed in size1 the apparatus provides a means of getting a definite instantaneous current of identical value whenever needed4 ,fig4 #bcb4 ,,magneto-,,inductor4 #cfd ,,standard ,,electrical ,,dictionary4 ,magnetometer4 7a7 ,a reflecting galvanometer1 with heavy magnetic needle1 dampened by a copper frame4 ,it was devised by ,weber4 7b7 ,an apparatus for measuring the intensity of magnetic force4 ,it may consist of a magnet suspended by bifilar or by torsion suspension4 ,a reflecting mirror and scale as in the reflecting galvanometer may be used to act as indicator of its motions4 ,it is used in investigations of the intensity of the earth's field4 ,if the motions of the spot of light are received on a moving strip of sensitized paper and are thereby reproduced photographically1 the instrument is self-recording4 ,such an apparatus is used in the ,kew ,observatory1 ,eng41 for recording the terrestrial magnetic elements4 ,magnetometry4 ,the determination of the magnetic moment of a magnet4 ,it involves the determination by experiment of--7 a7 the product of the magnetic moment1 ,m1 of the magnet by the horizontal component1 ,h1 of the earth's magnetism2 7b7 the quotient of ,m divided by ,h4 ,knowing these two quantities1 ,m is given by the formula ,m ,square,root7 7,m 99 ,h7 99 7,m_/,h7 7 and if desired ,h is given by the formula ,h ,square,root7 7,m99,h7 _/ 7,m_/,h774 ,m99,h is determined by the method of vibrations4 ,a very long1 thin magnet suspended by a torsion filament is caused to oscillate1 and its period is determined4 ,calling such period ,t and the moment of inertia of the magnet ,i1 we have the formula ,t #b99 ,,pi 99 ,square,root7 ,i _/ 7,h99,m7 7 7a71 whence ,h99,m is calculated1 ,i of course being known or separately determined4 ,fig4 #bcc ,,end-,,on ,,method4 ,fig4 #bcd4 ,,broadside ,,method4 ,m_/,h is determined by the ,end-on deflection method1 or the ,broadside deflection method4 ,in both cases the deflection of a compass needle by the magnet in question is the basis of the work4 ,in the end-on method ,,ab is the magnet under examination2 ,,de the compass needle2 a the angle of deflection2 d the distance between ,c and the middle of ,,ab1 which should be considerable compared with the length of ,,de2 #bl1 the length of ,,ab4 ,we then have the formula tan a 7,m_/,h7 99 7#b;d _/ 7d#b - l#b7b71 which if #bl is small compared to d reduces to tan a ,m_/,hd #c 7b71 which gives ,m_/,h1 a and d being known4 #cfe ,,standard ,,electrical ,,dictionary4 ,in the broadside method the line d is the magnetic meridian1 and the diagram shows the relative positions4 ,we then have the formula tan a 7,m_/,h7 _/ 7d#b l#b7a4e2 which if #a is relatively small reduces to tan a ,m_/7,h 99 d#c 77,c47 ,transcriber's note3 ,the image of the above paragraphs is included here4 a and c or a and b can be combined giving ,m and ,h in ,c4,g4,s4 measurement4 ,magnetometer1 ,differential4 ,an apparatus1 invented by ,eickemeyer1 for testing the magnetic qualities of different samples of iron4 ,it is very similar in construction and principle to the magnetic bridge1 q4 v4 ,magneto-motive ,force4 ,the force producing a magnetic field or forcing lines of force around a magnetic circuit4 ,it is usually applied only to electro-magnets and is expressible in turns of the wire winding multiplied by amperes of current1 or in ampere-turns4 ,magnet ,operation4 ,a term in surgery2 the use of the electro-magnet or permanent magnet for removing particles of iron from the eye4 ,magnetoscope4 ,an apparatus for detecting the presence of magnetism1 without measuring its intensity4 ,a simple magneto-scope consists of a magnetized bit of watch-spring suspended in a vertical glass tube by a fine filament4 ,a bit of unmagnetized soft iron wire may be used in the same way4 ,the first has the advantage of indicating polarity2 the latter merely shows magnetic attraction4 ,a cork may be used as base of the instrument4 ,fig4 #bce4 ,,magnetoscope4 #cff ,,standard ,,electrical ,,dictionary4 ,magnet1 ,permanent4 ,a bar of steel charged with residual magnetism4 ,steel possesses high coercive force in virtue of which when once magnetized it retains part of the magnetization4 ,permanent magnets are generally straight bars or ,u shaped2 they are termed bar magnets1 magnetic needles1 horseshoe magnets1 machine magnets and otherwise1 according to their shape or uses4 ,magnet ,pole4 ,the part of a magnet showing strongest polarity2 the part which attracts iron the most powerfully1 and acts as the starting point for lines of force4 ,magnet ,poles1 ,secondary4 ,magnet poles are often not situated at the ends4 ,owing to inequality of the material or other causes they may occupy intermediate positions on the magnet4 ,such poles are called secondary poles4 ,magnet ,pole1 ,unit4 ,a unit magnet pole is one which exerts unit force on another unit pole placed at unit distance from it4 ,unit force is the dyne2 unit distance is one centimeter4 ,magnet1 ,portative ,power of4 ,the power of sustaining a weight by attraction of its armature possessed by a magnet4 ,in general terms the adherence of the armature of a magnet to the pole varies with the square of the number of lines of force which pass through the point of contact4 ,hence an increased adherence of the armature to a horseshoe electro-magnet is sometimes obtained by diminishing the area of contact of one pole which concentrates the lines of force4 ,steel magnets were frequently made with rounded ends to increase the portative power4 ,magnet1 ,simple4 ,a magnet made of one piece of metal1 or at least magnetized as such2 the reverse of a compound magnet1 which is magnetized piece by piece and then fastened together4 ,magnet1 ,solenoidal4 ,a magnet which is so uniformly magnetized and is so long in proportion to its other dimensions that it virtually establishes two magnetic poles1 one at either end4 ,it is a long thin bar so magnetized that all its molecules would1 considered as magnets1 be absolutely equal4 7,daniell47 ,it acts like a solenoid1 except that it is longer in proportion than the solenoid generally is constructed4 ,magnet1 ,sucking4 ,a magnet coil with movable or loose axial bar of soft iron4 ,the whole is usually mounted vertically4 ,when a strong enough current is passed the bar is drawn up into the coil as if by suction1 whence the name4 #cfg ,,standard ,,electrical ,,dictionary4 ,magnet1 ,unipolar4 ,no such thing as a unipolar magnet is possible4 ,the name is given to poised or suspended magnets1 one of whose poles lies in the axis of suspension4 ,it is obvious that such a magnet will act1 as far as its directive tendency and rotatory movements are concerned1 as if it had only one pole4 ,as shown in the cut1 the pole s in both magnets lies in the axis of suspension or directly under the filament by which they are suspended1 while the other pole n is the active pole in causing rotation or directive tendency2 c c are counterweights or counterpoises4 ,fig4 #bcf4 ,,unipolar ,,magnets4 ,magnetophone4 ,an apparatus for producing a loud sound1 involving the principles of the telephone4 ,a rapidly alternating or make and break current being produced by any means and being transmitted through the telephone gives a loud note of pitch dependent on the current producing it4 ,sometimes a perforated metallic disc is rotated in a magnetic field1 and produces the requisite type of current4 ,magnus' ,law4 ,a law of thermo-electricity4 ,in a homogeneous circuit1 however1 the temperature varies from point to point2 there is no current4 ,whatever potential differences may be established by the variations in temperature it is evident that they must counteract each other and reduce to zero4 ,mains1 ,electric4 ,the larger conductors in a system of electric light or power distribution4 ,make4 v4 ,to complete a circuit1 as by closing a switch4 ,make and ,break ,current4 ,a current which is continually broken or interrupted and started again4 ,it is applied only where the makes and breaks succeed each other with great rapidity1 as in the action of an induction coil or pole changer1 etc4 ,it has had considerable importance in litigation affecting the ,bell telephone patents1 the courts holding that the original ,bell patent 7,no4 #agd1dfe1 of #ahgf17 covered the undulating current1 for the transmission of speech4 ,many efforts have been made by litigants to prove that specific telephones have transmitted articulate speech by the make and break current1 but without success4 ,if this could have been proved the assumption is that the courts would have sustained the use of such device as not infringing upon the claims of the ,bell patent4 ,malapterurus4 ,a fish1 sometimes called the thunder fish1 an inhabitant of ,african rivers1 occurring in the ,nile and ,senegal4 ,it possesses considerable electric power1 similar to that of the gymnotus and torpedo1 although inferior in amount4 #cfh ,,standard ,,electrical ,,dictionary4 ,fig4 #bcg4 ,,malapterurus4 ,man-hole4 ,the cistern-like depression in the ground for giving access to the ends of tubes in electric conduits4 7,see ,conduit1 ,electric ,subway47 ,marked ,end or ,pole4 ,the north pole or north seeking pole of a magnet1 so called because it is usually marked with a notch or scratch by the maker4 ,the south pole is called the unmarked end4 ,mass4 ,the quantity of matter in a body4 ,the ,c4 ,g4 ,s4 unit of mass is the quantity of matter in a gram4 ,while weight varies with latitude and other circumstances1 mass is invariable4 ,the unit of mass is also defined as the quantity of matter which in a balance will counterpoise a standard mass1 the gram or pound4 ,as the gram is intended to be the mass of one cubic centimeter of water at #c4ji ,c4 7#ci ,f471 the ,c4 ,g4 ,s4 unit of mass is really #a4jjjjac gram4 ,as a primary unit its dimensions are indicated by ,m4 ,mass1 ,electric4 ,a term for quantity of electricity4 ,the unit mass is such a quantity as at unit distance will act with unit force4 ,matter1 ,electric4 ,the imaginary substance constituting electricity2 a conception used purely as a matter of convenience4 ,transcriber's note3 ,the electron was discovered five years after this publication4 ,matter1 ,radiant4 ,matter in the ultra-gaseous or so-called fourth state4 ,in the gaseous state the molecules of a gas are in perpetual kinetic motion1 colliding actually or virtually with each other1 rebounding from such approach1 and striking also the walls of the containing vessel4 ,but except for these deflections1 which are of enormous frequency1 the paths of the molecules would be perfectly straight4 ,in the radiant state matter exists in so high a vacuum that collisions of the molecules rarely occur1 and the molecules simply beat back and forth in straight lines from side to side of the containing vessel4 ,a layer of gas in this condition is termed a ,crookes' layer1 from ,prof4 ,william ,crookes1 who discovered and investigated these phenomena4 #cfi ,,standard ,,electrical ,,dictionary4 ,luminous streams of the molecules are produced by electric high potential discharges between electrodes4 ,the course of the discharge is normal1 in general terms1 to the surfaces of the electrodes1 and reaches from one to the other in a curve or straight line1 as the case may be4 ,these luminous streams are deflected by a magnetic field2 if brought to a focus can heat refractory material in that focus to a full white heat1 and can develop phosphorescence4 ,the latter is termed electric phosphorescence4 ,a great variety of experiments have been devised to illustrate the phenomena of radiant matter4 ,the vacuum is generally produced in a hermetically sealed glass vessel into which the electrodes are sealed1 and which contain the phosphorescent substances or other essentials for the experiments4 ,the vessels are termed ,crookes' ,tubes4 ,transcriber's note3 ,crookes reported on radiant matter in #ahgi4 ,it is actually electrons1 but he failed to distinguish them from ordinary atoms4 ,thompson properly described electrons in #ahig4 ,matteueci's ,experiment4 ,an experiment for showing the inductive effect of the discharge of a ,leyden jar4 ,two glass plates are supported on standards in a vertical position4 ,flat coils of wire are wound or coiled and secured to one surface of each plate4 ,one plate has much finer and longer wire than the other4 ,metal handles are connected to the ends of the coarser wire coil4 ,the plates are placed with their coils facing each other4 ,a ,leyden jar is discharged through the coarser coil1 while the handles are grasped by a person4 ,the shock of the discharge is felt by him4 ,matting1 ,electric ,floor4 ,matting or floor covering underlaid with burglar alarm contacts1 so arranged as to be closed by anyone walking on the matting4 ,the contacts are connected to a burglar alarm system4 ,the object is to provide an alarm if a burglar enters a house1 in case he should enter a door or window without sounding the bell4 ,the latter can be done by cutting out the window or part of the door instead of opening it4 ,maxwell's ,theory of ,light4 ,a theory of light4 ,it is due to ,j4 ,clerk ,maxwell4 ,it supposes the phenomena of electric induction to be due to the ether1 q4 v4 ,it supposes the condition of the ether when conveying light to be the same as if exposed to the induction of rapidly alternating currents or discharges 7in this case synonymous74 ,it therefore is an electro-magnetic effect if the theory is correct4 ,an electric stress such as one due to the induction of an electrostatically charged body is not a wave-creating element or factor1 but is a simple stress4 ,but let this stress be stopped and renewed and at once it appears as a wave-forming agency4 ,this stoppage and renewal represents evidently a discharge succeeded by a charge1 or if repeated is equivalent to an intermittent current or an alternating one4 #cgj ,,standard ,,electrical ,,dictionary4 ,again the electrostatic stress kept constant may by being carried through space carry with it a wave1 just as a moving projectile carries a wave of air in advance of itself4 ,admitting this much the following consequences follow3 ,since in non-conductors the displacement produces a restitution force1 which varies as the displacement which is requisite or is a criterion for the propagation of waves1 while in conductors no such force is manifested and the electric energy appears as heat1 it follows that light vibrations are not possible in conductors1 because electro-magnetic waves do not exist in them when they are in circuit1 and conductors should be opaque1 while the reverse is true for non-conductors4 7,daniell47 ,this is carried out often enough to make a striking evidence in favor of ,maxwell's theory4 ,the velocity of propagation of an electro-magnetic disturbance in a non-conductor should be equal to that of light4 ,this constant is proved by mathematical considerations1 to be approximately the same as the ratio of the electrostatic to the electromagnetic unit of intensity or quantity4 ,this ratio is #c;,e#aj 7#cj1jjj1jjj1jjj71 which is almost exactly the velocity of light4 ,it also follows from what has been said that if an electrostatically charged body were whirled around a galvanometer needle at the rate of #c;,e#aj revolutions per second it should affect it like a circulating current4 ,this rate of rotation cannot be attained1 but ,rowland has made manifest the effect of a rotating statically charged body upon a magnetic needle4 ,the above is the merest outline of ,maxwell's theory4 ,the full development must be studied in his own and succeeding works4 ,mayer's ,floating ,magnets4 ,an experiment due to ,prof4 ,mayer4 ,a number of sewing needles are magnetized and thrust into bits of cork1 almost all the way through1 with their like poles projecting4 ,they are floated in a basin of water and take1 under the effects of attraction and repulsion1 when approached by a magnet pole1 regular geometric positions1 marking out the positions of angles of polygons4 ,measurements4 ,the determination of the value of quantities2 determination of the factor by which the unitary value must be multiplied to produce the quantity under examination4 ,such are the measurement of the voltage of a galvanic battery1 or of the ohms of resistance of a conductor4 ,electricity has been termed the science of measurement4 ,meg or ,mega4 ,a prefix1 meaning one million times4 ,a megohm is one million ohms2 a megerg is one million ergs2 a megadyne is one million dynes4 #cga ,,standard ,,electrical ,,dictionary4 ,fig4 #bch4 ,,mayer',s ,,floating ,,magnets4 ,mercury4 ,a metal2 one of the elements2 symbol1 ,hg2 atomic weight1 #bjj 2 equivalent1 #bjj or #ajj2 valency1 #a and #b4 ,it is a conductor of electricity4 ,the following data are #j ,c4 7#cb ,f47 ,relative ,resistance1 #fb4gc ,specific ,resistance1 #id4cb microhms4 ,resistance of a wire1 7a7 #a foot long1 weighing #a grain1 #ah4ea ohms4 7b7 #a foot long1 #a_/ajjj inch thick1 #egb4c 7c7 #a meter long1 weighing #a gram1 #ab4ia 7d7 ,i meter long1 #a millimeter thick #a4baa ,resistance of a #a inch cube1 #cg4ae microhms4 ,percentage increase of resistance per degree ,c4 #a4h ,f4 at about #bj ,c4 7#fh ,f471 4#gb per cent4 ,electro-chemical equivalent 7,hydrogen 4#jaje71 #b4aj mgs4 #a4je #cgb ,,standard ,,electrical ,,dictionary4 ,mercury ,cup4 ,a cup of iron1 wood or some material that does not amalgamate or is unattacked by mercury1 which is filled with mercury and made an electrode of a circuit4 ,by dipping the other terminal of the circuit into the mercury a very good contact is obtained4 ,it is well to cover the mercury with alcohol4 ,the cup may be filled so that the mercury rises in a meniscus or semi-globule above its edges4 ,for some purposes this form is useful1 as for contacts with the end of a swinging wire or pendulum1 because in such cases the contact can be made without the contact point entering the cup4 ,the point swings through the projecting meniscus without touching the edges of the cup4 ,a mercury cup and contact constitute a mercury break4 ,meridian1 ,astronomical4 ,the great circle passing through the north and south poles of the celestial sphere4 ,it lies in a plane with the corresponding geographical or terrestrial meridian4 ,meridian1 ,geographic4 ,the true north and south meridian2 the approximate great circle formed by the intersection of a plane passing through north and south poles of the earth with the earth's surface4 #cgc ,,standard ,,electrical ,,dictionary4 ,fig4 #bci4 ,,schallenberg',s ,,alternating ,,current ,,meter4 ,meter1 ,alternating ,current4 ,a meter for measuring alternating current1 as supplied to consumers1 from an alternating current system4 ,like most commercial meters its only function is the measurement of quantity2 the potential difference is maintained at a constant figure by the generating plant4 ,the cut shows the ,schallenberg meter4 ,it is simply an alternating current motor 7see ,motor1 ,alternating ,current71 with air vanes mounted on its spindle4 ,a main coil passes all the current4 ,within this is a second coil complete in itself1 and not touching or connecting with the other4 ,the latter is built up of copper rings4 ,within the two coils1 and concentric with both is a disc of copper carried by a vertical spindle4 ,the same spindle carries air vanes1 and is free to rotate4 ,as it does so it moves the indicating machinery4 ,the current in the outer coil induces one in the inner coil4 ,owing to lag1 the current in the inner one differs in phase from that in the outer one1 and a rotatory field is produced4 ,the copper disc acquires induced polarity1 and rotates with speed which normally would be in proportion to the square of the current4 ,but the object of the meter is to register the current only4 ,the air vanes effect this4 ,the resistance of the air to their motion causes the rate of rotation to vary directly as the speed4 ,meter ,bridge4 ,a form of ,wheatstone's bridge in which one lateral pair of arms is represented by a straight wire4 ,the other pair comprise a known resistance1 and the resistance to be determined4 ,the galvanometer is connected on one side between the known and unknown resistance4 ,on the other side its connection is moved back and forth along the straight wire until the balance is secured and the galvanometer reads zero4 ,the relative lengths of wire intercepted between the two ends thereof and the movable galvanometer connection are proportional to the resistance of these parts and give the necessary data with the one known resistance for determining the unknown resistance4 #cgd ,,standard ,,electrical ,,dictionary4 ,in the original meter bridge the wire was one meter long1 whence its name1 and was stretched straight4 ,in more recent examples the wire varies in length and in one form is bent into a circle or spiral1 so as to make the instrument more compact4 ,the contact is not a sliding one1 but is adjusted by trial4 ,the contact piece is slid along1 but not touching the wire1 and from time to time is pressed down against the wire4 ,this prevents wear of the wire4 ,the wire may be made of platinum or of platinum-iridium alloy4 ,the latter is very hard and not easily worn out4 ,sometimes1 as shown in the cut1 three parallel wires are stretched along the baseboard of the instrument1 and arranged so that a single wire1 two wires or three wires in series can be used for the proportional sides of the bridge1 thus making it a two-meter or three-meter bridge as desired4 ,on the other hand some are made of restricted length1 as a half or quarter meter only4 ,fig4 #bdj4 ,,meter ,,bridge4 ,in the cut ,j ,k is the wire1 traversed by the contact key4 ,by moving the contact ,c back and forth in the slot it can be brought over any of the three divisions of the wire4 ,h is the handle for depressing the key4 ,s is a flat spring1 carrying the contact piece and holding it up from the wires1 except when pressed downwards4 ,as shown in the cut1 it is in use for calibrating a voltmeter ,v1 by ,poggendorff's method1 ,g being the galvanometer and r#a and r#b being resistances4 ,synonyms--,slide ,bridge--,slide ,balance4 ,meter ,candle4 ,a unit of illuminating power2 the light given by one standard candle at a distance of one meter4 ,the ordinary units of illuminating power are altogether relative2 this one is definite4 #cge ,,standard ,,electrical ,,dictionary4 ,meter1 ,chemical ,electric4 ,a current meter in which the current is determined by the amount of chemical decomposition which it can effect4 ,in the ,edison meter the solution is one of zinc sulphate4 ,two electrodes of zinc are immersed in it1 and a fractional part of the current is passed through it4 ,the gain in weight of one electrode and the loss in the other are proportional to the current4 ,both electrodes are weighed periodically1 one acting as check upon the other4 ,meter1 ,current4 ,an instrument for measuring the quantity of electricity in current form supplied to consumers4 ,it may be of various types4 ,the general principle involved is that in commercial installations for incandescent light and power supply a fixed potential is usually maintained1 the multiple arc system being employed4 ,hence all that is requisite is to measure the coulombs or the ampere-hours to know what quantity of energy has been supplied4 ,meter1 ,electro-magnetic4 ,a current meter in which the current is measured by its electro-magnetic effects4 ,meter-millimeter4 ,a unit of resistance4 7,see ,resistance1 ,meter-millimeter47 ,meter1 ,thermal ,electric4 ,a current meter in which the current is measured by the heat it imparts to a conductor4 ,in one meter a very light helix of mica is poised horizontally over a conductor1 and the whole is enclosed in a case4 ,as the wire is heated it causes an ascending current of air which rotates the vane1 and the latter moves delicate clockwork which moves indicating hands4 ,the hotter the wire the more rapidly the air ascends1 and consequently the speed of the vane is proportional to the current1 because the heat of the conductor is proportional thereto4 ,meter1 ,time ,electric4 ,an electric meter which measures the length of time during which current is used4 ,it assumes a constant current and potential4 ,it is virtually a clock1 which is turned on when the current passes1 and is turned off with the current4 ,meter1 ,watt4 ,a combined current and potential meter4 ,it is constructed on the general lines of a ,siemens' ,electro ,dynamometer4 ,if in it one coil is made of coarse wire and is placed in series with the current conductor1 and if the other is wound with fine wire and is connected as a shunt from point to point whose potential difference is to be determined1 the instrument becomes a watt meter4 ,synonym--,energy ,meter4 ,methven ,standard or ,screen4 ,a standard of illuminating power4 ,it is the light emitted by a three-inch ,argand gas flame through a rectangular aperture in a silver plate carried by a screen4 ,the aperture is of such size and so far distant from the flame as to permit the passage of exactly two candles illuminating power4 ,fig4 #bda4 ,,methven ,,screen #cgf ,,standard ,,electrical ,,dictionary4 ,mho4 ,a unit of conductance1 not in very general use4 ,it is the reciprocal of the ohm4 ,thus a resistance of ten ohms is a conductance of one-tenth mho4 ,mica4 ,a natural mineral1 a silicate of several oxides2 muscovite4 ,it is used as an insulator and dielectric4 ,its resistance per centimeter cube after several minutes electrification at #bj ,c4 7#fh ,f47 is #h4d;,e#ac ohms 7,ayrton74 ,its specific inductive capacity is #e1 air being taken at #a4 ,mica1 ,moulded4 ,an insulating material1 whose body is made of mica pulverized and cemented together with heat and pressure and some suitable cement4 ,shellac is often used as the cement4 ,micro4 ,a prefix meaning one-millionth of2 a micro-farad is one-millionth of a farad4 ,micrometer4 ,an instrument for measuring small distances or small differences4 ,it generally is based upon an accurate screw which may have a worm wheel for head1 actuated by a worm or helix with graduated head1 so that exceedingly small advances of the screw may be produced4 ,the pitch of the screw being known its actual advance is known4 ,micrometer1 ,arc4 ,a micrometer for measuring the distance between voltaic arc electrodes4 ,micron4 ,a unit of length4 ,it is one-millionth of a meter or four one-hundred-thousandths of an inch4 #cgg ,,standard ,,electrical ,,dictionary4 ,microphone4 ,an apparatus which includes a contact of variable resistance2 such resistance can be varied in amount by slight vibrations1 such as those produced by sound waves4 ,the apparatus in use forms part of a circuit including a telephone and current generator4 ,as the contact is varied the resistance of the circuit and consequently the current intensity changes and sounds are emitted by the telephone corresponding to such changes4 ,if the microphone is spoken to1 the telephone will emit corresponding sounds1 reproducing the voice4 ,it has been found in practice that carbon gives the best microphone contact4 ,one of the simplest and earliest forms is shown in the cut4 ,a short rod or pencil of carbon1 ,a1 such as used in batteries1 is sharpened at the ends and rests loosely in a vertical position between two blocks of carbon1 ,c ,c1 in each of which a hole is drilled to receive one of the points4 ,the blocks are carried on a standard and base ,d4 ,the blocks are connected with two terminals x1 y1 of a circuit1 including a telephone and battery4 ,there are two contacts to be disturbed4 ,if delicately adjusted a fly walking over the base-board will disturb the contacts enough to produce sounds in the telephone4 ,these sounds are possibly not due only to sound waves1 but in part to absolute mechanical disturbances4 ,the various forms of telephone transmitter are generally microphones4 ,fig4 #bdb4 ,,microphone4 ,microphone ,relay4 ,a combined microphone and telephone4 ,a microphone is placed close to the diaphragm of a telephone4 ,the slight sound waves emitted by the telephone affect the microphone and are repeated in its circuit4 ,the microphone circuit includes a local battery and telephone4 ,microtasimeter4 ,an apparatus for indicating minute changes in temperature or atmospheric moisture4 #cgh ,,standard ,,electrical ,,dictionary4 ,a button of compressed lampblack is placed in series with a battery and galvanometer4 ,a strip of some substance1 affected in its length either by heat or by moisture1 is held pressing against the button4 ,a slight change in length of the strip varies the resistance of the button and hence affects the galvanometer4 ,in this way exceedingly slight changes in heat or moisture may be indicated4 ,for heat indications vulcanite may be used4 ,the heat of the hand held near it is enough to affect the galvanometer4 ,for moisture a slip of gelatine is used4 ,the moisture of a damp slip of paper two or three inches distant is sufficient to affect the galvanometer4 ,in the cut1 ,fig4 #b1 shows the general distribution of the apparatus in circuit with a battery and galvanometer4 ,c is the base of the apparatus1 from which the standard1 ,b1 with adjusting screw1 ,h1 rises4 ,the strip of vulcanite is held between ,i and ,g4 ,within ,d is the carbon button 7,f in ,fig4 #c7 pressed between ,g and ,e2 ,a is a standard to carry the parts last described4 ,in ,fig4 ,i it is shown as part of a ,wheatstone bridge1 a1 b and c being resistance coils2 l the tasimeter1 and g the galvanometer4 ,if a balance is secured1 any variation in the resistance of the tasimeter will disturb the galvanometer4 ,synonym--,tasimeter4 ,fig4 #bdc4 ,,microtasimeter4 #cgi ,,standard ,,electrical ,,dictionary4 ,mil4 ,a unit of length2 one-thousandth part of a lineal inch4 ,it is equal to 4#jbecii millimeter2 4#jjjjhc foot2 4#jjajjj inch4 ,mil1 ,circular4 ,a unit of area2 employed in designating the cross-sectional area of wires and other circular conductors4 ,it is equal to 4#ghedj square mil2 4#jjjejg square millimeter2 #g4h;,e-#g 74#jjjjjjgh7 square inch4 ,if the diameter of a wire is given in mils1 the square of its diameter gives its cross-sectional area in circular mils4 ,mil-foot4 ,a unit of resistance4 7,see ,resistance1 ,mil-foot1 ,unit of74 ,mil1 ,square4 ,a unit of area2 one-millionth of a square inch4 ,it is equal to 4#jjjfde square millimeter2 #a4bgcc circular mil2 4#jjjjja square inch4 ,milli4 ,a prefix2 one-thousandth4 ,thus a milligram is one-thousandth of a gram2 a millimeter is one thousandth of a meter4 ,milligram4 ,a unit of weight 2 one-thousandth of a gram1 q4 v4 ,it is equal to 4#jaedcb grain2 4#jjjjcb troy ounce4 ,millimeter4 ,a unit of length2 one-thousandth of a meter4 ,it is equal to #ci4cgjgi mils2 4#jcicg inch2 4#jjaji yard4 #chj ,,standard ,,electrical ,,dictionary4 ,milli-oerstedt4 ,a proposed but not adopted unit of current2 one-thousandth of an oerstedt4 ,it is equal to one-thousandth of an ampere4 ,transcriber's note3 oersted3 #a4 ,,cgs unit of magnetic intensity1 equal to the magnetic pole of unit strength when undergoing a force of one dyne in a vacuum4 #b4 ,formerly1 the unit of magnetic reluctance equal to the reluctance of a centimeter cube of vacuum between parallel surfaces4 mm4 ,contraction for millimeters4 ,molar4 ,referring to phenomena of mass as gravitation4 ,mechanics generally treats of molar laws and phenomena4 ,transcriber's note3 ,molar1 or mole1 often refers to a quantity of a substance containing an ,avagadro number 7#f4jb;,e#bc7 of molecules--a weight equal to the atomic weight of the molecule4 ,for example1 a mole of hydrogen 7,h#b7 is #b4jae grams2 sodium chloride 7,na,cl7 is #eh4ddc grams4 ,molar ,attraction4 ,the attraction of mass for mass2 gravitation4 ,synonyms--,mass ,attraction--,gravitation4 ,molecular ,affinity4 ,the attraction of molecules for each other as seen in the formation of double salts1 the combining of water of crystallization with a salt1 and in other cases2 a phase of affinity belonging to chemistry1 although outside of true atomic attraction4 ,molecular ,attraction4 ,the attraction of molecules2 physical affinity4 ,cohesion1 the attraction of similar molecules for each other1 and adhesion1 that of dissimilar molecules1 are examples4 ,this should be distinguished from molecular affinity1 a phase of chemical force4 ,molecular ,bombardment4 ,when a gas contained in a vessel is brought to a sufficient state of rarefaction the molecules cease to be subject to the laws of diffusion1 but move back and forth in straight lines from side to side of the vessel4 ,their courses can be affected by electric discharge1 which can cause them to all impinge upon one of the electrodes1 the positive one1 producing luminous effects4 ,the path1 if referred to the negative electrode1 tends to be normal to its surface1 so that the resultant path may be curved1 as the stream of molecules go to the positive electrode4 ,the fanciful name of molecular bombardment is given to the phenomenon1 the luminous effect being attributed to the impinging of the molecules against the positive electrode as they are projected from the positive4 ,the course of the molecules is comparable to the stream of carbon particles from the positive to the negative electrode in an arc lamp4 7,see ,matter1 ,radiant47 ,molecular ,chain4 ,the theoretical rows of molecules supposed to extend from anode to cathode in an electrolytic cell 7see ,cell1 ,electric--,grothss' ,hypothesis7 are called molecular chains4 #cha ,,standard ,,electrical ,,dictionary4 ,molecular ,rigidity4 ,the tendency of the molecules of a mass to retain their position in a mass in resistance to polarizing or depolarizing force1 the first being the effect of a magnetic field4 ,it is the theoretical cause of coercive force1 q4 v41 and of residual magnetism4 7,see ,magnetism1 ,residual47 ,molecule4 ,the smallest particle of matter that can exist alone4 ,it is made up of atoms1 but an atom can never exist alone1 but only1 with one or two possible exceptions1 combined with one or more other atoms as a molecule4 ,the molecules under present conditions are not in constant contact with each other1 but are perpetually vibrating through paths1 in solids probably in defined paths1 in liquids and gases in perpetually new paths4 ,the molecules collide with each other and rebound4 ,this motion is the kinetic motion termed heat4 ,at the absolute zero--minus #bgc4gb ,c4 7-#dfj4g ,f47 the molecules would be in contact and quiescent4 ,in the gaseous state the molecules of most substances occupy the same volume2 those of a few elements occupy one-half and of others twice the normal volume4 ,the mean free path of the molecule of hydrogen is about #a_/bj1jjj mm4 7#a_/ejh1jjj inch7 7,maxwell7 or twice this length 7,crookes71 the collisions in hydrogen are about #ag1gej millions per second2 the diameter is about #h_/aj1jjj1jjj mm4 7#h_/bed1jjj1jjj inch7 2 ,a particle of matter #a_/d1jjj mm4 7#a_/ajb1jjj inch7 contains1 it is supposed1 about #dj1jjj molecules4 ,the results of different authorities vary so widely as to deprive the subject of much of its interest4 ,a ,sprengel pump1 such as used for exhausting ,geissler tubes1 or incandescent lamp bulbs1 may leave only one hundred-millionth 7#a_/ajj1jjj1jjj17 of an atmosphere present1 giving the molecules a capability of an average free path of vibration #cc feet long4 ,moment4 ,when a force is applied so as to tend to produce rotation around a point1 the product of the force by the shortest distance from the point of rotation to the extension of the line of the force4 ,such distance is the perpendicular to the extension of the line through the point of rotation4 ,mordey ,effect4 ,a phenomenon observed in dynamo armatures4 ,at full loads the hysteresis decreases4 ,the effect is thus expressed by ,s4 ,p4 ,thompson4 ,when an armature core is rotated in a strong magnetic field1 the magnetization of the iron is being continually carried through a cycle1 but in a manner quite different from that in which it is carried when the magnetizing force is periodically reversed1 as in the core of a transformer4 ,mordey has found the losses by hysteresis to be somewhat smaller in the former case than in the latter4 ,morse ,receiver4 ,the receiving instrument formerly universally used in the ,morse system4 ,it is now but little employed1 the sounder having displaced it4 ,several types were invented4 ,it consists of machinery which carries a reel of paper ribbon arranged to be fed over a roller by clockwork4 ,a pencil1 inking roller1 or embossing stylus 7for the latter the roller must have a groove7 is carried by an arm with restricted range of vibration just over the paper and roller4 ,the armature of an electro-magnet is attached to the arm4 ,when the magnet is excited the armature is attracted and the marking device is pressed on the paper4 ,if the clockwork is in operation the marker will make a line as long as the armature is attracted4 ,when released no mark will be produced4 ,in this way the dots and dashes of the ,morse code are made on a ribbon of paper4 ,as an inking arrangement a small roller is carried by the end of the vibrating arm4 ,the embosser1 or dry point stylus1 was very extensively used4 ,the clockwork was generally driven by descending weights4 ,synonym--,morse ,recorder4 #chb ,,standard ,,electrical ,,dictionary4 ,mortar1 ,electric4 ,an electric toy which may have various modifications4 ,in the cut a wooden mortar with recess to receive a ball is shown4 ,two wires enter the base but do not touch4 ,on placing the ball in position and passing a spark from a ,leyden jar across the interval between the wires1 the heat and disturbance are enough to project the ball4 ,gunpowder may be used1 the discharge being passed through a wet string to prolong the spark4 ,fig4 #bdd4 ,,electric ,,mortar4 ,motor1 ,compound or ,compound ,wound4 ,a motor which has two windings on the field magnets1 one in parallel with that on the armature1 the other in series therewith1 exactly as in a compound dynamo4 7,see ,dynamo1 ,compound47 ,motor1 ,differential4 ,a differentially wound motor2 with a compound wound field1 whose series coil and shunt coil are wound in opposition to each other4 ,it is virtually a compound wound dynamo4 7,see ,dynamo1 ,compound ,wound47 ,motor1 ,electric4 ,a machine or apparatus for converting electric energy into mechanical kinetic energy4 ,the electric energy is generally of the dynamic or current type1 that is to say1 of comparatively low potential and continuous or virtually continuous flow4 ,some electrostatic motors have1 however1 been made1 and an influence machine can often be operated as a static motor4 ,electric motors of the current type may be divided into two classes--direct current and alternating current motors4 ,direct current motors are generally based on the same lines of construction as dynamos4 ,one of the great discoveries in modern electricity was that if a current is passed through a dynamo1 the armature will rotate4 ,this fact constitutes the principle of the reversibility of the dynamo4 #chc ,,standard ,,electrical ,,dictionary4 ,motors built on the dynamo model may be series wound1 shunt wound1 or compound wound1 or of the magneto type1 in the latter case having a fixed field irrespective of any current sent through them4 ,the field may be produced by an electro-magnet separately excited and unaffected by the current sent through the motor4 ,a current passed through a magneto or motor with separately excited field will turn it in the direction opposite to that required to produce the same current from it were it worked as a generator4 ,a current passed through a series wound motor acts exactly as above4 ,both these facts follow from ,lenz's law1 q4 v4 ,a current passed through a shunt wound motor acts oppositely to the above4 ,the direction of rotation is the same as that required to produce a current of the same direction4 ,this is because the field being in parallel with the armature the motor current goes through the magnet coils in the direction the reverse of that of the current produced in the armature when it is used as a dynamo4 ,hence this also carries out ,lenz's law4 ,the compound wound motor acts one way or the other according as its shunt or series winding preponderates4 ,the two may exactly balance each other1 when there will be no motion at all4 ,the series connections of a compound wound dynamo should therefore be reversed1 making both series and shunt work in unison1 if the dynamo is to be used as a motor4 ,the general principles of the electric motor of the dynamo1 or continuous rotation type1 can only be outlined here4 ,the current passing through the field magnets polarizes them and creates a field4 ,entering the armature by the brushes and commutators it polarizes its core1 but in such a way that the north pole is away from the south pole of the field magnet1 and the same for the south pole4 ,hence the armature rotates4 ,as it does this the brushes connect with other commutator sections1 and the poles of the armature are shifted back4 ,this action continues indefinitely4 ,another class of motors is of the reciprocating type4 ,these are now very little used4 7,see ,motor1 ,reciprocating47 ,one valuable feature of continuous rotation electric motors is the fact that they absorb energy1 to a great extent proportional in amount to the work they have to do4 ,the rotation of the armature in the field of the motor involves the cutting of lines of force by its coils4 ,this generates an electro-motive force contrary in direction to that producing the actuating current4 ,the more rapid the rotation the greater is this counter-electro-motive force4 ,the motor armature naturally revolves faster with diminished resistance to the motion of the armature4 ,this increases the counter-electromotive force1 so that less energy is absorbed4 ,when the motor is called on to do work1 the armature rotates more slowly1 and the counter-electro-motive force diminishes1 so that the machine absorbs more energy4 7,see ,jacobi's ,law47 #chd ,,standard ,,electrical ,,dictionary4 ,motor ,electro-motive ,force4 ,the counter-electro-motive force of a motor4 7,f4 ,j4 ,sprague47 ,a motor rotates in virtue of the pull of the field magnet upon the poles of the core of its armature4 ,in responding to this pull the windings of the armature cuts lines of force and hence generates a counter-electro-motive force1 for which the above term was suggested4 ,motor-,generator4 ,a combined motor and generator used to lower the potential difference in a portion of a circuit1 e4 g41 that part within a building4 ,a motor-generator is a dynamo whose armature carries two commutators1 with two separate windings1 one of fine wire of many turns1 the other of coarse wire of few turns4 ,if the potential of the system is to be lowered1 the main current is passed through the fine winding4 ,this causes the armature to turn motor-fashion1 and a potential difference is generated by the rotation of the large coils in the field4 ,this potential difference is comparatively low and by properly proportioning the windings may be lowered to as great a degree as required4 ,the same apparatus may be inverted so as to raise potential difference4 ,it acts for continuous current systems as the induction coil transformer does for alternating current systems4 ,synonym--,continuous ,current ,transformer4 ,motor1 ,multiphase4 ,a motor driven by multiphase currents4 ,it is arranged in general terms for distribution of the multi phase currents in coils symmetrically arranged around the circle of the field4 ,these coils are wound on cores of soft iron4 ,a rotating field is thus produced1 and a permanent magnet or a polarized armature pivoted in such a field will rotate with the field1 its poles following the poles of the rotatory field4 ,the cut1 ,fig4 #bde1 illustrates the principles of action of a four phase current motor1 connected to a four phase current dynamo or generator4 ,the generator is shown on the left hand of the cut and the motor on the right hand4 ,in the generator the armature ,n ,s is supposed to be turned by power in the direction shown by the arrow4 ,each one of the pair of coils is wound in the reverse sense of the one opposite to it1 and the two are connected in series with each other1 and with a corresponding pair in the motor4 ,the connection can be readily traced by the letters ,a ,a'1 a a' for one set of coils and ,b ,b' b b' for the other set4 #che ,,standard ,,electrical ,,dictionary4 ,for each rotation of the armature two currents1 each in opposite direction1 are produced in ,a ,a'1 and the same is the case for ,b ,b'4 ,these currents which have an absolutely constant relation of phase1 and which it will be seen alternate four times for each rotation of the armature1 regulate the polarity of the field of the motor4 ,the resultant of their action is to keep the poles of the field magnet of the motor constantly traveling around its circle4 ,hence the armature ,n ,s of the motor1 seen on the right hand of the cut1 tends to travel around also its north and south poles1 following the south and north poles of the rotatory field respectively4 ,fig4 #bde4 ,,four-,,phase ,,current ,,generator ,,and ,,motor4 ,it is not essential that the armature should be a magnet or polarized4 ,any mass of soft iron will by induction be polarized and will be rotated1 although not necessarily synchronously1 with the rotatory field4 ,any mass of copper1 such as a disc or cylinder1 will have ,foucault currents induced in it and will also rotate4 ,the only components of such currents which are useful in driving the motor are those which are at right angles to the lines of force and to the direction of motion4 ,a very good type of armature based on these considerations is a core of soft iron wound with insulated copper wire in one or more closed coils2 and so wound as to develop the currents of proper direction4 ,such an armature is used in the ,tesla alternating current motor4 ,an efficiency of #he per cent4 has been attained with some of the ,tesla motors4 ,motor1 ,prime4 ,a machine used for producing mechanical motion against resistance4 ,it may operate by converting heat or any other form of kinetic or potential energy into mechanical energy of the moving type4 ,a steam-engine and a water-wheel are examples of prime motors4 ,motor1 ,reciprocating4 ,the early type of motor depending upon reciprocating motion1 such as the motion of a coil in a solenoid4 ,these were based upon the lines of a steam engine1 and have been abandoned except for special purposes where reciprocating motion is especially required1 as in the case of rock drills4 #chf ,,standard ,,electrical ,,dictionary4 ,fig4 #bdf4 ,,ricordon',s ,,reciprocating ,,motor4 ,in the cut1 ,b is an electro-magnet2 ,a is an armature2 ,e a pole piece4 ,the current enters by the springs1 b b1 and by commutation is supplied and cut off alternately1 thus maintaining a reciprocating movement of the armature and rotation of the fly-wheel4 ,synonym--,pulsating ,motor4 ,motor1 ,series4 ,a motor whose winding on the armature is in series with the winding on the field4 ,it is similar to a series dynamo4 7,see ,dynamo1 ,series47 ,motor1 ,shunt4 ,a motor whose winding on the armature is in parallel with the winding on the field magnets4 ,it is similar to a shunt wound dynamo4 7,see ,dynamo1 ,shunt47 ,fig4 #bdg4 ,,multiple ,,arc ,,connection4 ,multiple4 ,a term expressing connection of electric apparatus such as battery couples1 or lamps in parallel with each other4 ,in the ordinary incandescent lamp circuits the lamps are connected in multiple4 ,synonym--,multiple ,arc4 #chg ,,standard ,,electrical ,,dictionary4 ,multiple ,arc ,box4 ,a resistance box arranged so that the coils may be plugged in multiple instead of in series4 ,such can be used as a rheostat1 as the resistance can be very gradually changed by putting the coils one by one into parallel with each other4 ,thus by adding in parallel with a #aj ohm coil a #aj1jjj ohm coil the resistance is decreased to #i4iiijja ohms1 and thus the resistance can be very slowly changed without sudden stops or abrupt changes4 ,transcriber's note3 ,the correct value is #i4iijja ,multiple ,series4 ,arrangements of electric apparatus in a circuit in a number of series1 which minor series are then arranged in parallel4 ,the term may be used as a noun1 as arranged in multiple-series1 or as an adjective1 as a multiple-series circuit4 ,fig4 #bdh4 ,,multiple ,,series ,,connection4 ,multiple ,switch ,board4 ,a switch board on whose face connecting spring jacks or other devices are repeated for the same circuits1 so that different operators have each the entire set of connections repeated on the section of the board immediately in front of and within their reach4 ,this multiplication of the same set of connections1 giving one complete set to each operator1 gives the title multiple to the type of switch board in question4 ,the typical multiple switch board used in telephone exchanges is the best example of this construction4 ,the calling annunciators of the subscribers are distributed along the bottom of the board extending its full length4 ,to each operator a given number is assigned1 all within reach of the right or left hand4 ,this gives five or six feet length of board to each1 and an operator only responds to those subscribers within his range4 ,but anyone of his subscribers may want to connect with any of the others in the entire central station4 ,accordingly in front of each operator spring jacks are arranged1 one for each of the entire set of subscribers connected in that office4 ,the operator connects as required any of the calling subscribers1 who are comparatively few1 to any one of the large number served by the central station4 ,thus the entire set of subscribers' spring jacks are multiplied over and over again so as to give one set to each operator4 #chh ,,standard ,,electrical ,,dictionary4 ,multiple ,wire ,method for ,working ,electro-magnets4 ,a method for suppressing sparking in working electro-magnets intermittently4 ,the magnet core is wound with a number 7from four to twenty7 of separate layers of fine wire4 ,a separate wire is taken for each layer and all are wound in the same direction1 from one end to the other of the space or bobbin without returning4 ,the ends are then joined so as to bring all the wires in parallel4 ,the effect of this is that as the coils vary in diameter the time constants of each is different from that of the others1 the coefficient of self-induction being less1 and the resistance being greater for the coils farthest from the central axis4 ,thus the extra currents run differently in the different coils1 and only a comparatively small spark can be produced owing to the division of forces thus brought about4 ,fig4 #bdi4 ,,diagram ,,illustrating ,,multiple ,,wire ,,working4 ,multiplex ,telegraphy4 ,any system of telegraphy transmitting more than four messages simultaneously over a single wire4 ,properly it should apply to all transmitting more than one1 but conventionally has the above restricted meaning1 distinguishing it from duplex and quadruplex telegraphy4 ,multiplying ,power of a ,shunt4 ,when a resistance is placed in parallel with a galvanometer on a circuit the following relation obtains4 ,let s and g equal the resistances of the shunt and galvanometer respectively1 ,s and ,g the currents in amperes passing through them1 ,v the potential difference between their common terminals1 and ,a the whole current in amperes4 ,then we have ,a 7 7s g 7 _/ s 7 99 ,g and 7 7s g 7 _/ s 7 is termed the multiplying power of the shunt1 as it is the factor by which the current passing through the galvanometer must be multiplied by to produce the total current4 ,muscular ,pile4 ,a species of voltaic battery1 often termed ,matteueci's pile1 made up of alternate pieces of muscle cut longitudinally and transversely respectively4 ,the different pieces represent the elements of a battery1 and their difference of potential is naturally possessed by the pieces4 ,myria4 ,a prefix2 one million times4 ,thus myriavolt means one million volts4 ,transcriber's note3 ,contemporary usage is mega1 as in megavolt4 #chi ,,standard ,,electrical ,,dictionary4 ,n4 7a7 ,symbol for north pole or north-seeking pole of a magnet4 7b7 ,symbol for the number of lines of force in a magnetic circuit4 ,nairne's ,electrical ,machine4 ,the cylinder electrical machine1 q4v4 ,napierian ,logarithms4 ,a series of logarithms the base of whose system is #b4gbhah4 ,they are also called hyperbolic logarithms4 ,nascent ,state4 ,an element just separating from a combination possesses at that time higher affinities than after separation1 and can effect more powerful chemical changes4 ,it is sometimes attributed to a differential time of existence in the atomic modification1 before the freed atoms have united to form molecules4 ,natural ,currents4 ,a term for earth currents4 7,see ,current1 ,earth47 ,needle4 7a7 ,a term applied to a bar magnet poised horizontally upon a vertical point1 or suspended in a horizontal position by a filament4 ,thus the magnet in a mariner's compass1 which may be a substantial bar magnet1 is called a magnetic needle4 7b7 ,an indicator in general shape like the hand of a clock4 7,sec ,annunciator1 ,needle- ,telegraph1 ,needle47 ,needle of ,oscillation4 ,the magnetic needle poised horizontally1 and used for measuring the intensity of the earth's magnetic field1 or of an artificial magnetic field1 by the method of oscillations4 ,the intensities of the field is inversely as the square of the number of oscillations performed in a given time4 ,needle1 ,telegraphic4 ,the index in needle telegraphy 7see ,telegraph1 ,needle71 whose motions indicate the characters it is desired to transmit4 ,negative ,charge4 ,one of the two kinds of electric charges4 ,the other is the positive4 ,by the double fluid hypothesis this is assumed to be a charge of a particular kind of electricity--negative electricity4 ,by the single fluid hypothesis it is supposed to be caused by the absence of part of the normal electricity of a surface4 ,the reverse is held by some theorists4 ,the subject is so purely theoretical that neither of the two hypotheses is accepted as final4 ,transcriber's note3 ,current is a wire is the motion of negative electrons4 ,current in a electrolyte is the motion of positive ions and negative ions4 ,current in a plasma is the motion of electrons and positive ions4 #cij ,,standard ,,electrical ,,dictionary4 ,negative ,electricity4 ,the kind of electricity with which a piece of amber is charged by friction with flannel2 resinous electricity4 7,see ,electrostatic ,series47 ,in a galvanic battery the surface of the zinc plate is charged with negative electricity4 ,according to the single fluid theory negative electrification consists in a deficiency of electricity4 ,transcriber's note3 ,negative electrification is an excess of electrons4 ,negative ,element4 ,in a voltaic cell the plate not dissolved by the solution2 the one which is positively charged2 the copper1 platinum1 or carbon plate in the usual type of battery4 ,the current is assumed to flow from negative element to positive element 7the zinc plate7 through the wire or other external conductor4 ,nerve ,currents4 ,currents of electricity obtained from nerves4 ,they are much more feeble than those obtained from muscle1 but are produced in the same general ways4 ,network4 ,conductors in parallel and crossing each other1 with connections at the junctions4 ,the term is sometimes so loosely applied as to include parallel conductors4 ,neutral ,line of ,commutator4 ,the diameter of a commutator which connects its ,neutral ,points1 q4 v42 sometimes termed the diameter of commutation2 the diameter approximately at right angles with the lines of force4 ,the commutator brushes are applied at the extremities of this diameter4 ,neutral ,point of a ,commutator4 ,the points of a commutator at which no lines of force are cut2 the points at the extremities of a diameter which1 except for the lag1 would be at right angles to the lines of force2 the points at which the brushes touch the commutator4 ,neutral ,point1 ,thermo-electric4 ,a temperature marking a point of no thermo-electric difference of potential4 ,if the junctions of a thermo-electric couple are at temperatures1 one a little over and the other an equal amount under the neutral point1 no current will be developed4 ,at the neutral point the thermo-electric polarities are reversed4 ,differences of temperature above it give currents of reverse direction to those given by corresponding differences below it4 ,for an iron-copper couple the neutral point is #bgd4e ,c4 7#ebf ,f47 ,synonym--,neutral ,temperature4 ,neutral ,relay ,armature4 ,an unpolarizable armature for use with a relay2 an armature of soft iron or iron wire2 as distinguished from a polarized armature4 #cia ,,standard ,,electrical ,,dictionary4 ,neutral ,wire4 ,the central wire in the three wire system1 q4 v41 of electric distribution2 the wire connected to a point between the two dynamos1 or otherwise to the central point of the current generator4 ,fig4 #bej4 ,,diagram ,,of ,,three ,,wire ,,system ,,showing ,,neutral ,,wire4 ,neutral ,wire ,ampere ,meter4 ,an ampere meter connected in the circuit of the neutral wire to determine the current passing through it4 ,such determination is for the purpose of ascertaining how much more work is being done by one of the lateral leads than by the other4 ,synonym--,balance ,ampere ,meter4 ,n4 ,h4 ,p4 ,symbol or contraction for nominal horse power4 ,this is a basis for rating the size of an engine4 ,nickel4 ,a metal2 one of the elements2 atomic weight1 #eh4h 2 equivalent1 #bi4d2 valency1 #b2 specific gravity1 #h4h4 ,it is a conductor of electricity4 ,relative resistance1 annealed 7,silver #a71 #h4bhe ,specific ,resistance1 #ab4dg microhms4 ,resistance of a wire 7a7 #a foot long1 weighing #a grain1 #ae4bjf ohms4 7b7 #a foot long1 #a_/ajjj inch thick1 #gd4ifc 7c7 #a meter long1 weighing #a gram1 #a4jfj 7d7 #a meter long1 #a millimeter thick1 4#aehg ,resistance of a #a-;inch cube1 #d4ijg microhms4 ,electro-chemical equivalent1 7,hydrogen 4#jaje7 4#cjhg mgs4 ,it is strongly paramagnetic1 but loses this quality at #cej ,c4 7#ffb ,f47 ,it is important as a constituent of ,german silver1 an alloy much used for resistance coils4 ,nickel1 ,bath4 ,a bath for the electro-deposition of nickel4 ,a great many formulae have been given4 ,metallic nickel is dissolved in #a vol4 sulphuric acid mixed with #b vols4 water4 ,neutralize with ammonia1 and add of ammonium sulphate one-half the weight of metallic nickel originally used2 #ace parts of nickel will be enough for a bath of #aj1jjj parts4 #cib ,,standard ,,electrical ,,dictionary4 ,other formulae are as follows3 ,double nickel-ammonium sulphate1 #d parts4 ,ammonium carbonate1 #c ,water #ajj ,nickel sulphate1 nitrate or chloride1 #a ,sodium bisulphate1 #a ,water1 #bj ,nickel anodes are used in the bath to maintain the strength4 ,too much care cannot be exercised in the absolute cleanliness of the articles to be plated4 ,a too alkaline bath gives a disagreeable yellow color to the deposit2 too acid a bath gives badly adhering deposits4 ,night ,bell4 ,an alarm bell in a telegraph office1 which bell is connected at night to give a loud signal to attract the operator's attention4 ,it is used in telephone exchanges and is connected so as to ring as long as a subscriber remains unanswered after calling4 ,nobili's ,rings4 ,when a dilute solution of copper acetate is placed on a bright silver plate and a strip of zinc is touched to the silver beneath the copper1 a series of rings of copper are formed by electrolysis around the zinc4 ,these are ,nobili's rings4 ,if for the copper acetate a solution of lead oxide in potassium hydrate solution is substituted1 and if the polished plate which may be ,german silver is connected to the positive electrode of a battery1 and a platinum wire connected to the negative pole is immersed in the liquid1 it determines the formation of beautiful iridescent rings of lead binoxide4 ,the platinum wire is sometimes sealed in glass so that only its point projects4 ,the colors are due to interference of light1 the layers of lead oxide being extremely thin4 ,the lead binoxide is formed by secondary reaction4 ,metallic lead is first deposited on the negative pole4 ,the oxygen which goes to the positive pole formed by the polished plate produces lead binoxide which is deposited there in rings4 ,the reaction is comparable to that of a storage battery4 ,synonyms--,metallochromes--,electric ,rings4 ,nodular ,deposit4 ,a deposit obtained in electroplating1 characterized by irregular thickness2 due to too low density of current4 ,non-conductor4 ,a material that does not conduct electricity except with great difficulty2 a substance of very high resistance4 ,synonym--,insulator--,dielectric4 ,north ,pole4 7a7 ,the north-seeking pole of a magnet2 the pole of a magnet which tends to point to the north1 and whence lines of force are assumed to issue on their course to the other pole of the magnet4 7b7 ,the ,north ,pole of the earth4 ,treating the earth as a magnet1 and accepting the above nomenclature the north pole should be termed the south pole4 7,see ,austral ,pole--,boreal ,pole47 #cic ,,standard ,,electrical ,,dictionary4 ,north-seeking ,pole4 ,the pole of a magnet which tends to point to the north2 the north pole of a magnet4 ,null ,method4 ,any method of obtaining measurements or comparisons1 in which the measurement is correct when the deflection of the galvanometer or other indicator is zero1 nought or null4 ,the ,wheatstone ,bridge 7see ,bridge1 ,wheatstone7 is an example of a null method4 ,two obvious advantages attach to null methods in electric galvanometer work4 ,one is that an uncalibrated galvanometer can be employed4 ,the other is that a galvanometer of any high degree of sensitiveness can be employed1 there being no restriction as to its fineness of winding or highness of resistance4 ,upper case ,omega ,graphic4 7,greek capital ,omega7 symbol for megohm4 ,transcriber's note3 ,now used for ohms4 ,lower case ,omega ,graphic4 7,greek omega7 symbol for ohm4 ,transcriber's note3 ,now used for angular velocity1 #b99,,pi99frequency4 ,occlusion4 ,an absorption of gases by metals4 ,palladium will1 if used as the hydrogen evolving electrode in decomposing water1 absorb #ihj times its volume of hydrogen1 which is said to be occluded4 ,the metal may also be heated in hydrogen and allowed to cool therein1 when occlusion occurs4 ,platinum will occlude #d times its volume of hydrogen2 iron1 #d4ae times its volume of carbon-monoxide2 silver1 #g times its volume of oxygen4 ,metals with occluded gases may serve as elements in a galvanic couple4 7,see ,gas ,battery47 ,a metal expands in occluding a gas4 ,in the storage battery it is believed that occlusion plays a part1 hydrogen and oxygen being respectively absorbed by the two sets of plates1 and acting as they do in ,groves' gas battery4 ,oerstedt4 ,name proposed for the unit of current strength1 but not adopted4 ,the ampere is the accepted name4 #cid ,,standard ,,electrical ,,dictionary4 ,oerstedt's ,discovery4 ,oerstedt discovered in #ahbj that a magnetic needle tended to place itself at right angles to a current of electricity4 ,this fundamental experiment is the basis of the galvanometer4 ,fig4 #bea4 ,,oerstedt',s ,,discovery4 ,ohm4 ,the practical unit of resistance2 #a;,e#i ,c4 ,g4 ,s4 electro-magnetic units4 ,the legal ohm is the resistance of a mercury column #a square millimeter in cross-sectional area and #ajf centimeters in length4 ,there has been considerable confusion1 owing to inaccuracy in early determinations1 in the valuation of the ohm4 ,in this work the legal ohm is used4 ,the different ohms will be found defined in their place4 ,resistance units of various names may also be consulted4 ,the following table gives the relative values of the different ohms4 ,length of ,mercury ,board of ,column in ,true ,b4 ,a4 ,trade ,legal ,centimetre4 ,ohm4 ,ohm4 ,ohm4 ,ohm4 ,true ,ohm1 #ajf4bd #a4 #a4jabh 4#iiid #a4jjbb ,b4 ,a4 ,ohm1 #ajd4i 4#ihgd #a4 4#ihfh 4#ihhi ,board of ,trade ,ohm #ajf4c #a4jjjej #a4jacc #a4 #a4jjbh ,legal ,ohm1 #ajf4j 4#iigg #a4jaab 4#iiga #a4 ,ohmage4 ,the ,resistance of a circuit expressed in ohms4 ,ohm1 ,b4 ,a4 ,the ,british ,association unit of resistance2 the resistance of a column of mercury #a square millimeter in cross sectional area and #ajd4i centimeters long2 the ,b4 ,a4 ,unit of ,resistance4 ,ohm1 ,board of ,trade4 ,the approximate ohm as recommended by the ,british ,board of ,trade on the advice of a committee 7,sir ,w4 ,thomson1 ,dr4 ,j4 ,hopkinson1 ,lord ,rayleigh and others74 ,it is the resistance of a mercury column one square millimeter in section1 and #ajf4c centimeters long at #j ,c4 7#cb ,f47 ,synonym--,new ,ohm4 #cie ,,standard ,,electrical ,,dictionary4 ,ohmic ,resistance4 ,true resistance as distinguished from spurious resistance1 or counter-electro-motive force4 ,ohm1 ,legal4 ,the practical unit of resistance4 ,the resistance of a column of mercury one square millimeter in cross-sectional area and #ajf centimetres long at #j ,c4 7#cb ,f47 ,the ohm used previously to #ahhd is the ,b4 ,a4 ,unit of ,resistance1 q4 v4 ,one legal ohm #a4jaab ,b4 ,a4 ,units1 and ,i ,b4 ,a4 ,unit #j4ihhi legal ohm4 ,the resistance of a copper wire #a foot long and #a_/ajjj inch in diameter is about #aj ohms4 ,the resistance of #a mile of iron wire #a_/c inch in diameter is about #aj ohms4 ,synonym--,congress ,ohm4 #cif ,,standard ,,electrical ,,dictionary4 ,fig4 #beb4 ,,theory ,,of ,,ohmmeter4 ,fig4 #bec4 ,,ohmmeter4 ,ohmmeter4 ,an instrument for measuring directly the resistance of a conductor or of any part of a circuit through which a strong current is passing4 ,it is the invention of ,prof4 ,w4 ,e4 ,ayrton4 ,it contains two fixed coils at right angles to each other acting on the same needle of soft iron4 ,one coil is of thick wire and is placed in series with the resistance to be measured4 ,the other is of very thin wire and is placed in parallel with the same resistance4 ,one wire acts by the total current1 the other by the potential difference between the ends of the resistance4 ,the action on the soft iron needle is due to the ratio of potential difference to total currents1 or to the resistance itself4 ,by properly designing and proportioning the coils the angular deflections of the needle are made proportional to the resistance4 ,in use the thick wire may be kept permanently in circuit4 ,on connecting the binding posts of the thin wire coil to any two parts of the circuit its resistance is at once given by the deflection of the needle4 ,when no current is passing the needle rests in any position4 ,a current in the thick coil brings it to zero4 ,a current simultaneously passing through the thin high resistance coil brings about the deflection4 ,the instrument is a commercial rather than a scientific one4 ,ohm's ,law4 ,the fundamental law expressing the relations between current1 electro-motive force and resistance in an active electric circuit4 ,it may be expressed thus3 7a7 ,the current strength is equal to the electro-motive force divided by the resistance4 7b7 ,the electro-motive force is equal to the current strength multiplied by the resistance4 7c7 ,the resistance is equal to the electro-motive force divided by the current strength4 ,all these are different forms of the same statement4 ,algebraically the law is usually expressed thus1 7a7 ,c ,e_/,r4 ,it may also be expressed thus3 7b7 ,e ,c99,r and 7c7 ,r ,e_/,c1 in which ,r denotes resistance1 ,c denotes current strength1 and ,e denotes electro-motive force4 ,ohm1 ,true4 ,the true ohm is the resistance of a column of mercury #a square millimeter in cross-sectional area1 and #ajf4bd centimeters long4 7,see ,ohm47 ,synonym-,rayleigh ,ohm4 ,oil ,insulation4 ,oil insulation has received several applications in electrical work4 ,it has been proposed for use in underground conduits4 ,these it was proposed to fill with oil after the insertion of the conductors1 the latter properly wrapped with cotton or other covering4 ,for induction coils it has been very successfully used4 ,its principal utility depends on the fact that it is liquid1 so that if pierced by a spark it at once closes again4 ,a solid insulator if pierced is permanently injured4 ,it is also used in telegraph insulators 7see ,insulator1 ,liquid7 to prevent surface leakage4 #cig ,,standard ,,electrical ,,dictionary4 ,olefiant ,gas4 ,a compound gas2 ,c#b;,h#d2 composed of carbon1 #bd2 hydrogen1 #d2 molecular weight1 #bh2 specific gravity1 4#iha4 ,it is a dielectric of about the resistance of air4 ,its specific inductive capacity at atmospheric pressure is #a4jjjgbb 7,boltzman47 ,synonym--,ethene2 heavy carburetted hydrogen4 ,transcriber's note3 ,also called ethylene4 ,a primary use is polyethylene plastic4 ,open4 adj4 ,an electric circuit is said to be open when it is cut or broken so that no current can pass through it4 ,the term may be recollected by thinking of a switch2 when open no current can pass through it4 ,the same adjective is applied to magnetic circuits1 an air gap implying an open circuit4 ,open ,circuit ,oscillation4 ,an oscillation of current in open circuit so that a spark discharge accompanies it4 ,it is produced by electric resonance in a simple circle or loop of wire with ends placed near together but not touching1 if the circuit is of such size that its period of oscillation corresponds with that of the inducing discharge4 7,see ,resonance1 ,electric47 ,its period depends entirely on the self-induction of the circuit4 ,ordinate4 ,in a system of plane co-ordinates 7see ,co-ordinates71 the distance of any point from the axis of abscissas measured parallel to the axis of ordinates4 ,ordinates1 ,axis of4 ,the vertical axis in a system of co-ordinates1 q4 v4 ,synonym--,axis of ,y4 ,organ1 ,electric4 ,an organ in which the air blast is admitted or excluded from the different pipes by electric mechanism4 ,the outlines of the system are a series of contacts worked by the keys and stops1 which cause1 when operated by the organist1 a current to pass through electro-magnets1 opening the valves of the different pipes4 ,thus the manual may be at any distance from the organ1 and a number of organs may be worked upon the same manual4 ,as many as five in a single cathedral are thus connected to a manual in the chancel4 ,orientation of a ,magnetic ,needle4 ,the acquirement by a magnetic needle of its position of rest1 with its magnetic axis in the magnetic meridian4 ,origin of ,co-ordinates4 ,in a system of linear co-ordinates the point of intersection of the axes2 the point whose co-ordinates are both zero4 #cih ,,standard ,,electrical ,,dictionary4 ,oscillating ,needle4 ,a small light bar magnet suspended by a filament and employed in determining the intensity of a magnetic field by the oscillations it completes in a given time after a given disturbance4 ,oscillations1 ,electric4 ,in static electricity the sudden and very rapid alternations in the discharge of a static condenser4 ,this discharge of the disruptive order seems a single one1 but is really composed of a number of discharges alternating in direction and producing electro-magnetic ether waves1 probably identical with light waves except that they are longer and far less rapid4 ,oscillatory ,electro-motive ,force4 ,electro-motive force rapidly changing in sense or in direction1 so that it presents an oscillatory character4 ,the alternating current and the telephone current as used in practice are actuated by this type of electro-motive force4 ,osmose1 ,electric4 ,when two liquids are separated by a porous diaphragm1 and a strong current of electricity is passed through from the liquid on one side1 through the diaphragm1 to the liquid on the other side1 the liquid on the side towards which the current is passing rises in level4 ,the process is termed electric osmose4 ,when a liquid is forced through a diaphragm a current is produced2 in other words electric osmose is reversible4 ,the current thus produced is termed a diaphragm current4 ,oscillation1 ,electric4 ,the phase of discharge of a static condenser in one direction4 ,it is usually followed by a discharge in the opposite direction constituting a second oscillation1 and so on1 so that a great number of exceedingly short oscillations are comprised4 ,thus1 in the discharge of the ,leyden jar a large number of oscillations of current back and forth are produced1 the current alternating like the swings of a pendulum4 ,these oscillations are supposed to affect the ether1 producing waves in it identical with light waves1 except that we have not been able yet to produce them short enough to affect the visual organs4 ,the waves thus produced can be reflected or refracted2 some substances are transparent for them and others opaque4 ,there is a possibility that man may yet succeed in producing electric oscillations of sufficient frequency to bring about the direct production of light4 ,oscillatory ,displacement4 ,hypothetical displacement currents of rapidly alternating direction produced in the oscillatory discharge of a ,leyden jar or static condenser4 ,oscillatory ,induction4 ,induction produced by sympathetic action of an oscillatory discharge or by electric resonance4 7,see ,oscillations1 ,electric--,resonance1 ,electric--,resonator1 ,electric47 #cii ,,standard ,,electrical ,,dictionary4 ,outlet4 ,the part of an electrolier or electric light fixture out of which the wires are led for attachment of an incandescent light socket4 ,output4 ,the rate of energy delivered or of work done by a machine4 ,in the case of a current generator it is the volt-coulombs per given second1 or better the volt-amperes delivered at its outer circuit terminals4 ,output1 ,magnetic4 ,the analogue in a magnetic circuit of the output of an electric circuit4 ,it is the product of the magnetizing force by the induced magnetism4 ,output1 ,unit of4 ,as a unit of output of a dynamo ,prof4 ,sylvanus ,p4 ,thompson has proposed #a1jjj watts1 or one kilowatt4 ,this unit is now frequently used4 ,to completely define the dynamo1 however1 the amperage or the voltage must also be given1 as a #aj kilowatt--#aaj volt machine1 or a #aj kilowatt--#ii ampere machine4 ,transcriber's note3 #aj kilowatt at #aaj volts is #ia amperes4 ,over-,compounding4 ,a proportioning of the series and shunt windings of a compound dynamo1 so that the voltage of the terminals rises with the load or output enough to allow for the drop in mains1 thus maintaining the potential for full load at distant points in a district4 ,it is carried out by an increase of ampere-turns in the series winding4 ,overload4 ,in an electric motor a mechanical load put upon it so great as to prevent economical working4 ,one effect of such a load is to make the armature run so slowly as to unduly reduce the counter-electro-motive force and hence to permit so much current to pass through the coils as to heat them1 perhaps injuriously4 ,in this case the production of heat implies the waste of energy4 ,overtype ,dynamo or ,motor4 ,a dynamo or motor whose armature is placed above or in the upper part of the field magnets1 the yoke piece of the magnets being in or resting upon the base of the machine4 ,ozone4 ,an allotropic form of oxygen4 ,it possesses much more energetic chemical properties than oxygen4 ,it is supposed to contain three atoms of oxygen in its molecule1 represented thus3 ,o _/ ,o---,o ,it is produced by electric discharges and it is its peculiar odor which is noticed about an electric machine1 and sometimes in a thunderstorm near the path of a lightning flash4 ,in the electrolysis of water some ozone may be produced1 thus diminishing the volume of the oxygen or of the mixed gases given off4 ,this is a source of inaccuracy in a gas voltameter4 #djj ,,standard ,,electrical ,,dictionary4 ,pacinotti's ,inductor4 ,the ,pacinotti or ,gramme ,ring4 7,see ,pacinotti's ,ring47 ,pacinotti's ,ring4 ,a ring of iron wire wound with coils of insulated wire at right angles to its circular axis1 and used as the armature of a dynamo or motor4 ,a number of connections are taken from the coils to a central commutator4 ,fig4 #bed4 ,,pacinotti',s ,,machine1 ,,with ,,ring ,,armature4 ,if such a ring with its coils is rotated in a field1 current can be taken from points of the commutator on a line at right angles to the lines of force entering the ring4 ,the ring was discovered in #ahfb by ,pacinotti1 and later was independently discovered by ,gramme4 ,it is often known as the ,gramme ring4 ,pacinotti ,teeth4 ,projections on a cylindrical or drum armature1 between which in the grooves formed thereby1 the wire is wound4 ,the teeth being of iron tend to diminish the reluctance or magnetic resistance of the interpolar space1 or interval between the poles of the field magnet4 ,synonym--,pacinotti ,projections4 ,paillard ,alloys4 ,non-magnetic palladium alloys1 invented by ,paillard1 of ,switzerland1 used in anti-magnetic watches4 ,the following are given as the compositions of several such alloys3 ,i4 ,,ii4 ,palladium1 #fj to #ge parts #ej to #ge parts ,copper1 ,i#e to #be #bj to #cj ,iron4 #a to #e #e to #bj #dja ,,standard ,,electrical ,,dictionary4 ,the following are more complex3 ,i4 ,,ii4 ,palladium1 #fe to #ge parts #de to #ej parts ,copper1 #ae to #be #ae to #be ,nickel1 #a to #e #b to #e ,silver1 #c to #aj #bj to #be ,gold1 #a to #b-a_/b #b to #e ,platinum1 #a_/b to #b #b to #e ,steel1 #a to #e #b to #e ,these alloys are used for balance springs1 as well as for the balance wheels and escapement parts of watches4 ,the elasticity of recently produced springs has been found to be very satisfactory4 ,page ,effect4 ,the sounds produced by magnetizing and demagnetizing a bar of iron or steel2 the magnetic tick4 ,the sounds are strong enough to produce a telephonic effect4 7,see ,magnetic ,tick47 ,palladium4 ,a metal of the platinum series4 ,it has the highest power of occlusion1 q4v41 of all metals4 ,it is the characteristic ingredient of non-magnetic watch alloys4 ,palladium used as an electrode in the electrolysis of water will occlude #icf volumes of hydrogen1 and the hydrogen-palladium alloy will exceed in size the original electrode4 ,fig4 #bee4 ,,luminous ,,pane4 ,pane1 ,luminous4 ,a pane of glass1 one side of which has pasted to it a long zigzag strip of tinfoil4 ,a design is made by cutting through the strip4 ,on discharging a ,leyden jar or an electric machine through the strip sparks appear where the tinfoil is severed1 thus producing the design in a luminous effect4 ,many variations can be employed in their construction4 #djb ,,standard ,,electrical ,,dictionary4 ,pantelegraphy4 ,a system of telegraphy for transmitting designs1 maps1 drawing1 and the like by telegraphy4 7,see ,telegraphy1 ,facsimile47 ,paper ,filaments4 ,filaments of carbon for incandescent lamps made from paper4 ,this is one of the earliest materials practically used4 ,the paper is cut out of proper shape1 and is carbonized in a close vessel1 while embedded in powdered charcoal or some other form of carbon to absolutely cut off access of air4 ,it is then placed in the lamp chamber and flashed or subjected to the regular treatment4 ,parabola4 ,a curve2 one of the conic sections4 ,it is approximately represented by a small arc of a circle1 but if extended becomes rapidly deeper than a half circle4 ,if1 from a point within called the focus1 lines are drawn to the curve and then other lines are drawn from these points parallel to the axis1 the angles of incidence will he equal to the angles of reflection as referred to tangents at the points where the lines touch the curve4 ,transcriber's note2 ,the general equation of a parabola is ,a99x#b ,b99x99y ,c99y#b ,d99x ,e99y ,f #j such that ,b#b #d99;,a99,c1 all of the coefficients are real1 and ,a and ,c are not zero4 ,a parabola positioned at the origin and symmetrical on the y axis is simplified to y a99x#b ,parabolic ,reflector4 ,a reflector for a light1 a paraboloid or surface of revolution whose section is a parabola4 ,a light placed at its focus has its rays reflected parallel to each other4 ,examples of parabolic reflectors are seen in electric search lights and in locomotive head-lights4 ,they are employed in electric search lights4 ,the arc light must be of such construction as to maintain its ignited points always at the same point1 the focus of the paraboloid4 ,paraffine4 v4 ,to coat or saturate with paraffine wax4 ,paper may be paraffined by dipping in the wax1 or by being sprinkled with fragments of wax1 subsequently melted in with a hot iron or otherwise4 ,the tops of battery carbons are often paraffined to prevent the acid from rising in the pores by capillary attraction and rusting the connections4 #djc ,,standard ,,electrical ,,dictionary4 ,paraffine ,wax4 ,a hydro-carbon composed principally of mixtures of the higher members of the paraffine series ,c n ,h#b n #b4 ,it is made from cannel coal1 coal tar1 or petroleum by distillation4 ,it is an insulator4 ,its resistance at #df ,c4 7#aad4h ,f47 per centimeter cube is #c4d;,e#af ohms1 or about the highest resistance known4 ,its specific inductive capacity 7for milky wax7 is #b4dg 7,schiller74 ,for clear wax it is given as follows by different authorities3 #a4ib ,ayrton4 #a4if ,wllner4 #a4igg ,gibson ,barclay4 #b4cb ,baltzmann4 ,it is extensively used in condensers and other electric apparatus as a dielectric and insulator4 ,paragrles4 ,protectors against hail2 lightning rods used to guard fields against hail2 of little or no real utility4 ,parallax4 ,the apparent change in position of an object when looked at from two points of view4 ,by looking at an object a few feet distant first with one eye and then with the other1 the shifting in apparent position is seen4 ,in reading the position of an indicator or needle over a scale parallax introduces an error unless the eye is held vertically over the needle4 ,by making the dial of looking- glass and holding the eye so that the reflection of its pupil is bisected by the needle this verticality is ensured4 ,parallel4 7a7 ,in the nomenclature of electric circuits two or more conductors leading from one point to another1 are said to be in parallel4 7b7 ,when two or more conductors connect two main leads of comparatively large size and low resistance they are said to be in parallel or in multiple arc4 ,this order is easiest pictured as the rungs of a ladder in parallel connecting its two sides representing the main leads4 ,it may be used as a noun as arranged in parallel1 or as an adjective as a parallel circuit1 the opposite of series1 q4 v4 ,paramagnetic4 adj4 ,possessing paramagnetic properties2 tending to occupy a position with the longer axis parallel to the lines of force of a magnetic field2 having magnetism2 attracted by a magnet4 ,if a homogeneous isotropic substance is placed in a magnetic field it becomes magnetized at every point in the direction of the magnetic intensity at that point1 and with an intensity of magnetization proportional to the magnetic intensity4 ,when the positive direction of the induced magnetization is the same as that of the magnetic intensity the substance is called ,magnetic or ,paramagnetic2 when it is opposite1 the substance is called ,diamagnetic4 7,emtage47 ,a paramagnetic substance has high permeability or multiplying power for lines of force1 hence in a magnetic field a bar of iron1 etc41 is in unstable equilibrium unless its longer axis is parallel with the lines of force in order to reduce as much as possible the reluctance of the circuit4 #djd ,,standard ,,electrical ,,dictionary4 ,iron is the most paramagnetic of all substances4 ,other paramagnetic metals are3 ,nickel1 cobalt1 manganese1 platinum1 cerium1 osmium1 palladium4 ,diamagnetic metals are bismuth1 antimony1 zinc1 tin1 mercury1 lead1 silver1 copper1 gold1 arsenic4 ,bismuth is the most diamagnetic of all metals4 ,of gases oxygen is most paramagnetic4 ,becquerel calculated that a cubic yard of oxygen condensed would act on a magnetic needle as powerfully as #e4e grains of metallic iron4 ,liquefied oxygen will adhere to the poles of a magnet4 ,changes of temperature and of other conditions may affect a body's magnetism4 ,thus hot oxygen is diamagnetic1 and a substance paramagnetic in a vacuum may be diamagnetic in air4 ,of liquids1 solutions of iron or cobalt are paramagnetic2 water1 blood1 milk1 alcohol1 ether1 oil of turpentine and most saline solutions are diamagnetic4 ,paramagnetism4 7a7 ,the science or study of paramagnetic substances and phenomena4 7b7 ,the magnetic property of a paramagnetic substance2 that of being attracted by a magnet1 and of arranging itself with its longer axis parallel with the lines of force of a magnetic field4 ,parchmentizing4 ,if cellulose is treated with a mixture of two parts of sulphuric acid and one part of water perfectly cold1 it becomes like parchment4 ,it should at once be washed with water1 and then with ammonia and water4 ,the ,swan incandescent light fibres are made of parchmentized cotton thread1 which is afterward carbonized4 ,partial ,earth4 ,a fault in a conductor caused by imperfect connection with the earth1 where insulation from the earth is desired4 ,passive ,state4 ,a state of a substance in virtue of which it is unattacked by a solvent which ordinarily would dissolve or attack it4 ,iron in strong nitric acid is unattacked or assumes the passive state4 ,this particular case is supposed to be due to a coating of magnetic oxide1 so that there would be properly speaking no question of a passive state1 but only one of superficial protection4 ,the existence of a true passive state of any substance is very doubtful4 ,p4 ,d4 ,abbreviation for potential difference or difference of potential1 or for electro-motive force4 #dje ,,standard ,,electrical ,,dictionary4 ,peltier ,effect4 ,the thermal effect produced by the passage of a current through the junction of two unlike conductors4 ,such junction is generally the seat of thermo-electric effects1 and a current is generally produced by heating such a junction4 ,if an independent current is passed in the same direction as that of the thermoelectric current1 it cools the junction1 and warms it if passed in the other direction4 ,in general terms1 referring to thermo-electric couples1 if passed through them it tends to cool the hot and heat the cool junction4 ,the phenomenon does not occur in zinc-copper junctions4 ,peltier's ,cross4 ,a bar of bismuth and a bar of antimony soldered centre to centre at right angles1 being notched or halved there to receive or to set into each other4 ,it is used to demonstrate the ,peltier effect1 q4 v4 ,to one pair of ends are connected the terminals of a battery circuit2 to the other pair are connected the terminals of a galvanometer4 ,the galvanometer by its deflections in one and then in the other direction indicates that the junction is heated when the current passes from antimony to bismuth and vice versa4 ,it thus illustrates the heating and cooling of a thermo-electric junction by a current of electricity4 ,the current from the battery by the ,peltier effect either heats or cools the junction1 as the case may be4 ,this heating or cooling them produces a thermo-electric current in the galvanometer circuit4 ,the battery has no direct influence on the galvanometer4 ,pendant ,cord4 ,a double conductor or pair of conductors1 insulated from each other and covered with a worsted1 silk1 or cotton covering and used to suspend incandescent lamps and at the same time to conduct the current to them4 ,it is also used for other similar service1 such as acting as conductors for small motors4 ,often each conductor is composed of a number of thin wires laid together4 ,this gives flexibility to the cord4 ,synonym--,flexible ,cord4 ,pendulum1 ,electric4 7a7 ,a pendulum operated by the intermittent action of an electro-magnet1 whose circuit is opened and closed by the pendulum itself4 ,a point at the lower end of the pendulum swinging through a globule of mercury may close and open the circuit4 ,various other methods of accomplishing the same end are employed 44 7b7 ,a pith ball suspended by a thread from an insulating stand4 ,it is used to show the attraction exercised by a piece of sealing wax or other substance excited by rubbing4 #djf ,,standard ,,electrical ,,dictionary4 ,pen1 ,electric4 ,a stylus for producing a series of perforations in paper1 so that the paper may act as a stencil for the reproduction of a great number of copies of the original matter4 ,various kinds of electric pens have been invented4 ,one kind1 invented by ,edison1 consists of a handle carrying an electric motor actuating a needle1 which is driven in and out of the other end of the handle with high rapidity4 ,it is used by being held vertically on the paper with the needle end downward1 and is moved so as to describe perforated letters or designs4 ,the paper is then used as a stencil with an ink roller to reproduce the writing or design ad libitum4 ,a simpler kind dispenses with the motor and depends on the perforations produced by the electric spark4 ,as shown in the cut the stylus is one terminal of an induction coil circuit4 ,the support on which the paper rests is the other terminal and must be a conductor4 ,in use the induction coil is started1 and the stylus is moved over the paper2 a series of sparks pass through the paper from stylus to the supporting tablet1 perforating the paper and producing a stencil to be used for reproduction4 ,fig4 #bef4 ,,electric ,,pen4 ,pentane ,standard1 ,harcourt's4 ,a standard of illuminating power2 in it the combustible substance is a gas made by mixing one cubic foot of air with three cubic inches of liquid pentane1 measured at #fj ,f4 or1 if measured as gases1 #bj volumes of air to #g of pentane4 ,it is burned at the rate of #j4e cubic foot per hour from a cylindrical tube one inch in diameter1 closed at the top by a disc #j4e inch thick with a hole #j4be inch in diameter1 through which the gas issues4 ,it gives a flame #b4e inches high4 ,the pentane used is the distillate of petroleum which boils at #ej ,c4 7#abb ,f47 2 it has a specific gravity at #ae ,c4 7#fj ,f47 of from #j4fbh to #j4fca4 ,it is almost pure pentane 7,c#e;,h#ab74 ,as long as the rate of consumption is between #j4dh and #j4eb cubic foot per hour the flame gives practically the same light4 #djg ,,standard ,,electrical ,,dictionary4 ,perforator4 ,an apparatus used in automatic high speed telegraphy for perforating strips of paper4 ,these are then used by drawing between a roller and contact spring for making and breaking the telegraphic circuit for the production of a record1 such as the ,morse record1 at the distant receiving station4 ,the perforated strip has different classes of holes punched in it to represent dots or dashes4 ,it is fed by machinery very rapidly1 so that the message is transmitted with the highest speed4 ,several operators may simultaneously prepare the paper strips1 and thus in conjunction with its rapid feeding in the transmitter1 far surpass the time of ordinary direct transmission4 ,fig4 #beg4 ,,perforator ,,for ,,wheatstone',s ,,automatic ,,telegraph4 ,perforators may be entirely mechanical but are sometimes pneumatic1 compressed air being used to operate them4 ,the holes they make are on different levels of the paper strip1 as shown in the cut4 ,period4 ,the time required for the completion of one complete element of periodic motion4 ,this may be a complete alternation 7,see ,alternation1 ,complete7 of an alternating current1 or of an oscillatory discharge4 ,periodicity4 ,the rate of succession of alternations or of other fixed phases2 the rate of recurrence of phenomena4 #djh ,,standard ,,electrical ,,dictionary4 ,permanency4 ,in electric current conductors the property of possessing conductivity unaffected by lapse of time4 ,generally the permanency of conductors is very high4 ,in some cases a slow annealing takes place which causes a gradual change with the lapse of time4 ,annealed ,german silver wire has been found to increase in conductivity at about 4#jb per cent4 in a year4 7,matthiessen47 ,wire1 whether annealed or not1 is left in a strained condition after the drawing operations1 and such a change is consonant with this fact4 ,the figure only applies to the samples tested by ,matthiessen4 ,permanent ,state4 ,in a telegraph line or other current conductor1 the condition when a uniform current strength obtains over the whole line4 ,when a current is started it advances through the line with a sort of wave front gradually increasing in strength4 ,at the further end some time may elapse before it attains its full intensity4 ,when its does the permanent state prevails4 ,until then the variable state1 q4 v41 exists in the line4 ,permeameter4 ,an apparatus for determining the permeability of samples of iron4 ,it consists of a large slotted block of iron4 ,a coil is placed within the slot4 ,a hole is drilled through one end1 and a rod of the iron to be tested is passed through this hole and through the coil to the bottom of the slot4 ,the lower end of the rod must be accurately faced off4 ,the current is turned on1 upon which the rod adheres to the bottom of the slot4 ,the force required to detach it is determined with a spring balance4 ,the permeation through its face is proportional to the square of the force required4 ,fig4 #beh4 ,,permeameter4 ,permeance4 ,the multiplying or the conducting power for magnetic lines of force possessed by a given mass of material4 ,it varies with the shape and size of the substance as well as with the inducing force4 ,it is distinguished from permeability1 as the latter is a specific quality proper to the material1 and expressed as such2 the permeance is the permeability as affected by size and shape of the object as well as by its material4 #dji ,,standard ,,electrical ,,dictionary4 ,pflger's ,law4 ,a law of electro-therapeutics4 ,it states that stimulation of a nerve is only produced by successive appearance of the kathelectrotonic state1 and disappearance of the anelectrotonic state4 ,phantom ,wires4 ,the extra transmission circuits obtained in multiplex telegraph systems4 ,a single line arranged for four separate simultaneous transmissions by quadruplex apparatus is said to establish three phantom wires4 ,phase4 ,in wave motion1 oscillating motion1 simple harmonic motion1 or similar periodic phenomena1 the interval of time passed from the time the moving particle moved through the middle point of its course to the instant when the phase is to be stated4 ,pherope4 ,an apparatus for the electric transmission of pictures4 7,see ,telephote47 ,transcriber's note3 ,precursor of the contemporary ,fax and scanner4 ,philosopher's ,egg4 ,an ellipsoidal vessel mounted with its long axis vertical and with two vertical electrodes1 the upper one sliding1 and arranged to be attached to an air pump4 ,a discharge through it when the air is exhausted takes the general shape of an egg4 ,phonautograph4 ,an apparatus for registering the vibrations of a stylus1 which is mounted on a diaphragm and is acted on by sound waves4 ,it is virtually a resonating chamber1 over one of whose ends a parchment diaphragm is stretched4 ,to the centre of the parchment a needle or stylus is attached4 ,a cylinder covered with soot is rotated in contact with the point of the stylus4 ,as the chamber is spoken into the diaphragm and stylus vibrate and the vibrations are marked on the cylinder4 ,it is of some electric interest in connection with telephony4 ,phone4 ,colloquial abbreviation for telephone4 ,phonic ,wheel4 ,a form of small motor of very simple construction4 ,it consists of a toothed wheel of soft iron4 ,a bar electro-magnet is fixed with one pole facing the teeth of the wheel4 ,by a tuning fork make and break a succession of impulses of rapid frequency and short duration are sent through the magnet4 ,the teeth act as armatures and are successively attracted by the magnet4 ,the regulated speed is one tooth for each impulse1 but it may rotate at one-half the speed1 giving two teeth for each impulse1 or at certain other sub-multiples of its regular speed4 ,it is the invention of ,paul ,lecour4 #daj ,,standard ,,electrical ,,dictionary4 ,phonograph4 ,an apparatus for reproducing articulate speech4 ,it is not electric1 except as it may be driven by electricity4 ,it consists of a cylinder of wax-like material which is rotated and moved slowly1 longitudinally1 screw fashion1 at an even speed4 ,a glass diaphragm carrying a needle point is supported with the point barely touching the wax4 ,if the diaphragm is agitated1 as by being spoken against1 the needle is driven back and forwards cutting a broken line or groove following the direction of the thread of a screw in the wax1 the depth of which line or groove continually varies4 ,this imprints the message4 ,if the needle is set back and the cylinder is rotated so as to carry the needle point over the line thus impressed1 the varying depth throws the needle and diaphragm into motion and the sound is reproduced4 ,the cylinder is rotated often by an electric motor1 with a centrifugal governor4 ,transcriber's note2 ,due to ,t4 ,a4 ,edison1 #ahgg1 fifteen years before this book4 ,phonozenograph4 ,an apparatus for indicating the direction of the point where a sound is produced4 ,it operates by a microphone and telephone in conjunction with a ,wheatstone bridge to determine the locality4 ,phosphorescence4 ,the emission of light rays by a substance not heated1 but whose luminosity is due to the persistence of luminous vibration after light has fallen upon it4 ,a phosphorescent body1 after exposure to light1 is luminous itself4 ,phosphorescence may be induced by rubbing or friction1 by heat1 by molecular bombardment1 as in ,crookes' tubes1 and by static discharge of electricity1 as well as by simple exposure to light4 ,another form of phosphorescence may be due to slow chemical combustion4 ,this is the cause of the luminosity of phosphorous4 ,phosphorous1 ,electrical ,reduction of4 ,phosphorous is reduced from bone phosphate by the heat of the electric arc4 ,the phosphate mixed with charcoal is exposed to the heat of the voltaic are1 and reduction of the phosphorous with its volatilization at once ensues4 ,the phosphorous as it volatilizes is condensed and collected4 ,photo-electricity4 ,the development of electrical properties by exposure to light4 ,crystals of fluor spar are electrified not only by heat 7see ,pyro-electricity7 but also by exposure to sunlight or to the light of the voltaic arc4 ,transcribers note3 ,although first observed in #ahci by ,becquerel1 it was not explained until #aije by ,albert ,einstein with the introduction of photons4 ,photo-electric ,microscope4 ,a projection1 solar or magic-lantern microscope worked by the electric light4 ,photo-electro-motive ,force4 ,electro-motive force produced in a substance by the action of light4 #daa ,,standard ,,electrical ,,dictionary4 ,photometer4 ,an apparatus for measuring the intensity of light emitted by a given lamp or other source of illuminating power4 ,they may be classified into several types4 ,calorimetric or ,heat ,photometers act by measuring relatively the heat produced by the ether waves 7so-called radiant heat7 emitted by the source4 ,the accuracy of the instrument is increased by passing the rays through an alum solution4 ,a thermopile1 or an air thermometer1 may be used to receive the rays4 ,chemical ,photometers4 ,in these the light falls upon sensitized photographic paper4 ,the depth of coloration is used as the index of illuminating power4 ,direct ,visual ,photometers4 ,these include ,rumford's ,shadow ,photometer1 ,bunsen's ,bar ,photometer1 and ,wheatstone's ,bead ,photometer1 in which the light is estimated by direct visual comparison of its effects4 ,optical ,photometers4 ,these include ,polarization ,photometers1 in which the light is polarized2 ,dispersion ,photometers1 in which a diverging lens is placed in the path of the rays of light so as to reduce the illuminating power in more rapid ratio than that of the square of the distance4 ,selenium ,photometers1 in which the variations in resistance of selenium as light of varying intensity falls upon it is used as the indicator of the intensity of the light4 ,jet ,photometers1 for gas only1 in which the height of a flame under given conditions1 or the conditions requisite to maintain a flame of given height1 is used to indicate the illuminating power4 ,the subject of photometers has acquired more importance than ever in view of the extensive introduction of the electric light4 7,see ,candle1 ,standard--,carcel--,viol's ,standard--and ,photometers of various kinds47 ,photometer1 ,actinic4 ,a photometer whose registrations are produced by the action of the light being tested upon sensitized paper or plates1 such as used in photography4 ,some efforts at self-registering photometers have been based on actinic registration of the height of a flame of the gas to be tested4 ,photometer1 ,bar4 ,a photometer in which the two lights to be compared are fixed at or opposite to the ends of a bar or scale of known length1 generally #fj or #ajj inches4 ,the bar is divided by the rule of the inverse square of the distances1 so that if a screen is placed on any part of the bar where it receives an equal amount of light from both sources1 the figure on the bar will indicate the relative illuminating power of the larger lamp or light in terms of the smaller4 ,the divisions of the bar are laid out on the principle that the illuminating power of the two sources of light will vary inversely with the square of their distance from the screen4 #dab ,,standard ,,electrical ,,dictionary4 ,the screen used is sometimes the ,bunsen disc4 ,this is a disc of paper with a spot of paraffine wax in the centre melted thoroughly into the paper or with a ring of paraffine wax surrounding the untouched centre4 ,when this disc is equally illuminated on both sides the spot is nearly invisible4 ,inequality of illumination brings it out more visibly4 ,sometimes a ,leeson disc is used4 ,this consists of three pieces of paper1 two thin ones between which a thicker piece1 out of which a star is cut1 is laid4 ,when equally illuminated on both sides the star appears equally bright on both sides4 ,the bar photometer is the standard form4 ,a candle or pair of candles may be burned at one end and an incandescent lamp at the other1 or a gas flame may first be rated by candles and used as a standard4 ,synonyms--,bunsen's ,photometer--,translucent ,disc ,photometer4 ,fig4 #bei4 ,,bar ,,photometer4 ,photometer4 ,calorimetric4 ,a photometer in which the radiant energy1 so called radiant heat1 is used as the measurer of the light4 ,in one type a differential air thermometer is used1 one of whose bulbs is blackened4 ,on exposing this bulb to a source of light it will become heated1 and if lights of the same character are used the heating will be in proportion to their illuminating power quite closely4 ,the heating is shown by the movements of the index4 ,by careful calibration the instrument may be made quite reliable4 ,photometer1 ,dispersion4 ,a photometer in which the rays from one of the lights under comparison are made more divergent by a concave lens4 ,in this way a strong light1 such as all arc lamp can be photometered more readily than where only the natural divergence of the beam exists4 ,the law of the variation of the intensity of light with the square of the distance is abrogated for a law of more rapid variation by the use of a concave lens4 ,the diagram1 ,fig4 #bfj1 illustrates the principle4 ,e represents a powerful light1 an arc light1 to be tested4 ,its distance from the screen is e4 ,its light goes through the concave lens ,l and is dispersed as shown over an area ,a#a1 instead of the much smaller area ,a1 which the same rays would otherwise cover4 ,calling l the distance of the lens from the screen1 f its focus1 and c the distance of the standard candle from the screen when the shadows are of equal intensity1 we have the proportion4 ,illuminating power of lamps3 ditto of standard candle33 7l 7e-l7 fe7#b 3 7c f7#b #dac ,,standard ,,electrical ,,dictionary4 ,fig4 #bfj4 ,,diagram ,,of ,,principle ,,of ,,the ,,dispersion ,,photometer4 ,the cut1 ,fig4 #bfa1 gives a perspective view of ,ayrton's ,dispersion ,photometer4 ,c is the standard candle1 ,l the concave lens1 ,r the rod for producing the two shadows on the screen ,s4 ,fig4 #bfa4 ,,ayrton',s ,,dispersion ,,photometer4 ,the mirror ,m is fixed at an angle of #de with the stem on which it rotates4 ,the light of the arc lamp is received by the mirror and is reflected through the lens4 ,the candle holder slides along a graduated bar ,c1 and at ,d is an index plate to show the angle at which the spindle carrying the mirror is set4 #dad ,,standard ,,electrical ,,dictionary4 ,dr4 ,j4 ,hopkinson in his dispersion photometer uses a double convex lens4 ,this gives a focal image of the arc-lamp between the lens and screen1 whence the rays diverge very rapidly1 thus giving the desired dispersion effect4 ,it is principally for arc lamps that dispersion photometers are used4 ,photometer1 ,shadow4 ,a photometer in which the relative intensity of the two lights is estimated by the intensity or strength of shadows of the same object which they respectively cast4 ,fig4 #bfb4 ,,rumford',s ,,shadow ,,photometer4 ,fig4 #bfc4 ,,rumford',s ,,shadow ,,photometer ,,arranged ,,for ,,testing ,,incandescent ,,lamps4 #dae ,,standard ,,electrical ,,dictionary4 ,a rod is supported in a vertical position4 ,back of it is a screen of white paper4 ,the two lights to be compared are arranged in front of the rod and at a little distance from each other4 ,they are shifted about until the two shadows appear of equal darkness4 ,the relative intensity of the lights varies inversely with the square of their distances from the shadows cast respectively by them on the screen4 ,the cut1 ,fig4 #bfb1 shows the simplest type of the shadow photometer4 ,in the cut1 ,fig4 #bfc1 a shadow photometer for testing incandescent lamps is shown4 ,in it ,e is the lamp under trial supported by a clamp ,h4 ,a is an ampere meter in circuit with the lamp1 and ,v is a voltmeter4 ,a candle ,c can be moved along a graduated scale ,g ,g4 ,r is the vertical rod1 and ,s is the screen on which the shadows fall4 ,photophore4 ,an instrument for medical examination of the cavities of the body4 ,it includes an incandescent lamp mounted in a tube with a concave mirror and convex lens4 ,photo-voltaic ,effect4 ,the change in resistance of some substances effected by light4 ,selenium1 of all substances1 is most susceptible to this effect4 7,see ,selenium47 ,piano1 ,electric4 ,a piano whose manual or key-board operates to close electric circuits1 whereby electro-magnets are caused to operate to drive the hammers against the strings4 ,pickle4 ,an acid solution for cleaning metal surfaces before electro-plating1 galvanizing or other deposition of metal upon them4 ,picture1 ,electric4 ,a picture produced by passing a strong discharge through a piece of gold leaf clamped or firmly pressed upon a sheet of paper4 ,the gold leaf is cut out of the desired shape1 or else a stencil of paper overlays it4 ,the discharge dissipates the gold1 and produces a purple colored reproduction of the design upon the paper4 ,the design is due to the deposition of an exceedingly thin film of metallic gold4 ,synonym--,electric ,portrait4 ,pile4 ,a galvanic or voltaic battery4 ,it is sometimes restricted to a number of voltaic couples connected4 ,it should be only applied to batteries with superimposed plates and no containing vessel such as the ,dry ,pile1 q4 v41 or ,volta's ,pile1 q4 v4 ,pilot ,transformer4 ,in alternating current distribution a small transformer placed at any part of the system and connected to a voltmeter in the central station1 to indicate the potential difference of the leads4 ,pilot ,wires4 ,wires brought from distant parts of electric light or power mains1 and leading to voltmeters at the central station1 so that the potential of distant parts of the system can be watched4 ,the wires can be very small1 as they have but little current to transmit4 #daf ,,standard ,,electrical ,,dictionary4 ,pistol1 ,electric4 ,an experimental apparatus for exhibiting the power of electric incandescence or of the electric spark4 ,a tube is mounted with a handle like a pistol4 ,a plug is provided to screw in and out of its side4 ,the plug carries two wires connected on its inner side by a fine platinum wire1 or else disconnected but with their ends brought near together to act as terminals for the production of a spark4 ,to use it the tube is filled with a mixture of air and gas1 the latter either hydrogen1 hydro-carbon or other combustible gas4 ,the tube when full is corked4 ,the wire is heated to incandescence by a current1 or a spark is passed from a ,leyden jar or other source of electrostatic excitation4 ,the mixture1 if properly proportioned1 explodes and expels the cork violently4 ,fig4 #bfd4 ,,electric ,,pistol4 ,pith4 ,a light and soft cellular tissue forming the central core of exogenous trees and plants4 ,in the older parts of the tree the woody tissue often encroaches in and partly obliterates it4 ,for electrical pith-balls1 the pith of the elder1 of corn1 or1 best of all1 of sun-flower stems is used4 ,pith-balls4 ,ball made of pith4 ,they are used in the construction of electroscopes and for other experiments in static electricity4 ,they are cut out with a sharp knife and their shape may be improved by gentle rolling in the hand or between the fingers4 ,pivot ,suspension4 ,suspension poising or supporting of an object on a sharp pivot4 ,this is used for the needle in the ordinary compass4 ,a cavity or inverted cup1 which may be made of agate1 is attached to the middle of the needle which has a hole for its reception4 ,the centre of gravity of the needle comes below the bottom of the cup4 ,pivot suspension is not perfect1 as it has considerable friction4 ,there is no restitution force1 as with torsion filaments4 #dag ,,standard ,,electrical ,,dictionary4 ,plant4 ,the apparatus for commercial manufacturing or technical works4 ,an electric lighting plant includes the boilers1 engines and dynamos for producing the current1 and the electric mains and subsidiary apparatus4 ,plant ,electricity4 ,electricity manifested by plant life4 ,by means of a galvanometer potential differences are found to exist in different parts of trees or fruits4 ,the roots and interior portions are negative1 and the flowers1 smaller branches and fruit are positive4 ,in some cases a contraction of the tissue of plants can be produced by an electric current4 ,the sensitive plant and others exhibit this phenomenon1 exactly analogous to the action of muscular tissue4 ,plate1 ,arrester4 ,in a lightning arrester the plate connected to the circuit4 ,sometimes both plates are designated arrester plates4 ,plate ,condenser4 ,a static condenser having a flat plate of glass for dielectric4 7,see ,epinus' ,condenser47 ,plate ,electrical ,machine4 ,a frictional electric machine1 in which a circular plate of glass is excited by friction with the cushions4 ,it is the most recent type of frictional machine and has superseded the old cylinder machines4 ,in its turn it is superseded by influence machines1 really plate machines1 but not so termed in practice4 ,plate1 ,ground4 ,in a lightning arrester1 the plate connected to the earth4 ,plate1 ,negative4 ,in a voltaic battery1 either primary or secondary1 the plate which is unattacked by the oxygen or negative radical or element of the fluid4 ,it corresponds to the carbon plate in the ordinary voltaic battery1 and is the one charged with positive electricity4 ,plate1 ,positive4 ,in a voltaic battery1 either primary or secondary1 the plate which is dissolved or attacked by the oxygen or negative radical or element of the fluid4 ,it is the plate corresponding to the zinc plate in the ordinary voltaic battery1 and is the one charged with negative electricity4 ,plating ,balance4 ,a balance or scales to which articles in an electroplater's bath are suspended4 ,a weight exceeding by a known amount that of the article as immersed overbalances the article4 ,when the plating is being deposited as soon as it exceeds the excess of weight of the counterpoise the balance tips1 the article descends a little1 the electric circuit is broken and the plating ceases4 ,thus the plating is automatically stopped when a predetermined amount of metal is deposited4 #dah ,,standard ,,electrical ,,dictionary4 ,plating ,bath4 ,a vessel of solution for the deposition of metal by electrolysis as used in electro-plating4 ,plating1 ,electro-4 ,the deposition of metal by electrolysis so as to coat the conducting surface of objects therewith4 ,the full details of the many processes are very lengthy and cannot be given here4 ,the general principle includes a battery or source of electric current4 ,the object to be plated is connected to the negative terminal and is immersed in the solution4 ,thus with a battery the object is in electrical connection with the zinc plate4 ,to the other terminal a metallic plate is connected4 ,the object and the plate termed the anode being introduced into a suitable bath1 the metal whose solution is in the bath is deposited upon the surface of the object4 ,the bath is a solution of the metal in some form that will lend itself to the electrolytic action4 ,the anode is often a plate of the metal of the bath1 so that it dissolves as fast as metal is deposited on the object1 thus keeping up the strength of the solution4 ,the objects to be plated must be scrupulously clean1 and great care must be taken to keep the bath uncontaminated4 ,when the object has a non-conducting surface1 it is made conducting by being brushed over with plumbago q4v4 ,in addition iron dust is sometimes dusted over it4 ,this acts by precipitating the metal of the bath directly and thus giving a conducting basis for the metal to deposit on4 ,to avoid getting iron in a bath the object may be dipped in copper sulphate solution4 ,this precipitates copper in place of the iron and leaves the article in good shape for silver or other plating4 ,electro-plating1 if made thick enough1 gives a reverse of the article when separated therefrom4 ,a direct copy can be got by a second plating1 on the first plating after separation1 or a wax impression can be employed4 ,under the different metals1 formulae for the baths will be found4 7,see also ,quicking-- ,steeling--,plating ,balance47 ,platinoid4 ,an alloy of copper1 nickel1 zinc in the proportions of ,german silver with #a or #b per cent of tungsten4 ,it is used for resistances4 ,it has a specific resistance 7or resistance per centimeter cube7 of about #cd microhms4 ,its percentage variation in resistance per degree ,c4 7#a4h ,f47 is only about 4#jba per cent41 or less than half that of ,german silver4 ,this is its most valuable feature4 #dai ,,standard ,,electrical ,,dictionary4 ,platinum4 ,a metal2 one of the elements2 symbol1 ,pt2 atomic weight1 #aig4d2 equivalent1 #di4ce2 valency1 #d2 specific gravity1 #ba4e4 ,it is a conductor of electricity4 ,the following data refer to the annealed metal at #j ,c4 7#cb ,f47 ,relative ,resistance 7,silver annealed #a71 #f4jbb ,specific ,resistance1 #i4jeg microhms4 ,resistance of a wire1 7a7 #a foot long1 weighing #a grain1 #b4ggi ohms4 7b7 #a foot long1 #a_/ajjj inch thick1 #ed4di 7c7 #a meter long1 weighing #a gram1 #a4ich 7d7 #a meter long1 #a millimeter thick1 4#aaec ,resistance of a #a inch cube1 #c4efe ,electro-chemical equivalent 7,hydrogen 4#jaje71 #j4eaha4 ,the coefficient of expansion by heat is almost the same as that of glass4 ,it can be passed through holes in glass and the latter can be melted about it so as to hermetically seal its place of passage through the glass4 ,it is used in incandescent lamps for leading-in wires and other similar uses4 ,platinum ,black4 ,finely divided platinum4 ,it is made by boiling a solution of platinic chloride with excess of sodium carbonate and a quantity of sugar1 until the precipitate is perfectly black and the supernatant liquid is colorless4 ,it seems to possess a great power of occluding oxygen gas4 ,when heated to redness it becomes spongy platinum4 ,the negative plates of a ,smee battery are coated with platinum black4 ,platinum-silver ,alloy4 ,an alloy of #a part platinum and #b parts silver1 used for resistance coils4 ,relative ,resistance 7silver annealed #a 71 #af4ba microhms4 ,specific ,resistance at #j;,c4 7#cb ,f471 #bd4ci ,resistance of a wire1 7a7 #a foot long1 weighing #a grain1 #d4aig ohms4 7b7 #a foot long1 #a_/ajjj inch diameter1 #adf4gj 7c7 #a meter long weighing #a gram1 #b4ibd 7d7 #a meter long1 #a millimeter diameter1 #j4cajf ,resistance of a #a inch cube1 #i4fjc microhms4 ,percentage ,variation per degree ,c4 7#a4h ,f47 at about #bj ,c4 7#fh ,f471 #j4jca per cent4 ,synonym--,platinum ,alloy4 ,platinum ,sponge4 ,finely divided platinum obtained by igniting platinum black1 q4v41 and also by igniting salts of platinum4 ,it has considerable power of condensing or occluding oxygen4 ,it will1 if in good condition1 set fire to a jet of hydrogen impinging upon it4 ,plow4 ,contact arms projecting downwards from the motors1 trucks1 or bodies of electric street cars1 which enter the underground conduit through the slot and carry contact pieces or brushes1 to take the current for driving the motors from the leads within the conduit4 #dbj ,,standard ,,electrical ,,dictionary4 ,plcker ,tubes4 ,a special form of ,geissler tube designed for the production of stratification and for observing the effects produced in the space surrounding the negative electrode4 ,plug4 7a7 ,a piece of metal with a handle and a somewhat tapered end1 used to make connections by insertions between two plates or blocks of metal slightly separated and with grooves to receive it4 7b7 ,a plug or wedge with two metallic faces1 insulated from each other with a separate wire connected to each one4 ,it is used in spring-jacks q4 v41 to introduce a loop in a circuit4 ,synonym--,wedge4 ,plug4 v4 ,to connect by inserting a plug1 as in a resistance box4 ,fig4 #bfe4 ,,plugs ,,for ,,resistance ,,coil ,,box4 ,fig4 #bff4 ,,plug ,,switch4 ,plug1 ,double4 ,a spring-jack plug or wedge with two pairs of insulated faces1 one behind the other1 so as to simultaneously introduce two loops into a circuit4 ,plug1 ,grid4 ,a piece or mass of lead oxide1 inserted into the holes in the lead plates of storage batteries4 ,the holes are often dovetailed or of uneven section to better retain the plugs4 ,plug ,infinity4 ,in a box-bridge or resistance box1 a plug whose removal from between two disconnected discs opens the circuit4 ,all the other discs are connected by resistance coils of various resistance4 ,plug ,switch4 ,a switch composed of two contact blocks1 not touching each other and brought into electrical connection by the insertion of a metallic plug4 ,the latter is usually provided with an insulating handle1 and a seat is reamed out for it in the two faces of the contact blocks4 #dba ,,standard ,,electrical ,,dictionary4 ,plumbago4 ,soft lustrous graphite1 a native form of carbon2 sometimes chemically purified4 ,it is used in electro-plating to give a conducting surface to non-conducting objects1 such as wax moulds4 ,the surface1 after coating with plumbago1 is sometimes dusted over with iron dust1 which precipitates the metal of the bath and starts the plating4 ,it is sometimes plated with copper1 silver or gold1 and is then termed coppered1 silvered1 or gilt plumbago4 ,it is gilded by moistening with etherial solution of gold chloride and exposing to the air1 and drying and igniting4 ,plunger4 ,a movable core which is used in connection with a so-called solenoid coil1 to be drawn in when the coil is excited4 7,see ,coil and ,plunger47 ,fig4 #bfg ,,coil ,,and ,,plunger ,,with ,,scales ,,to ,,show ,,attraction4 ,p4 ,o4 ,abbreviation for ,post ,office1 q4v4 ,poggendorf's ,solution4 ,an acid depolarizing and exciting fluid for zinc-carbon batteries4 ,the following is its formula3 ,water1 #ajj parts2 potassium bichromate1 #ab parts2 concentrated sulphuric acid1 #be parts4 ,all parts by weight4 ,use cold4 ,point1 ,neutral4 7a7 ,on a commutator of a dynamo the points at the ends of the diameter of commutation1 or where the brushes rest upon the surface of the commutator1 are termed neutral points4 ,at these points there is no generation of potential1 they marking the union of currents of opposite direction flowing from the two sides of the armature into the brushes4 7b7 ,in electro-therapeutics1 a place in the intra-polar region of a nerve so situated with reference to the kathode and electrode as applied in treatment1 that its condition is unaffected4 ,synonym--,indifferent ,point4 7c7 ,in a magnet the point of no attraction1 situated between the two poles1 at about an equal distance from each1 so as to mark the centre of a magnet of even distribution of polarity4 7d7 ,in thermo-electricity the point of temperature where the thermo-electric powers of two metals are zero2 in a diagram the point where the lines representing their thermo-electric relations cross each other2 if the metals are arranged in a thermo-electric couple1 one end at a temperature a given amount above1 the other at a temperature the same amount below the neutral point1 no current or potential difference will be produced4 #dbb ,,standard ,,electrical ,,dictionary4 ,point1 ,null4 ,a nodal point in electrical resonators2 a point where in a system of waves or oscillations1 there is rest1 the zero of motion being the resultant of oppositely directed and equal forces4 ,in electrical resonators it is to be sought for in a point symmetrically situated1 with reference to the spark gap1 or in a pair of points1 which pair is symmetrically placed4 ,the null point in resonators is found by connecting a lead from one of the secondary terminals of an induction coil to different parts of the resonator4 ,the null point is one where the connection does not give rise to any sparks between the micrometer knobs or spark gap1 or where the sparks are of diminished size4 ,the whole is exactly comparable to loops and nodes in a vibrating string or in a ,chladni plate as described in treatises on sound and acoustics4 7,see ,resonance1 ,electrical--,resonator1 ,electrical47 ,synonym--,nodal ,point4 ,point ,poles4 ,magnet poles that are virtually points1 or of no magnitude4 ,a long thin magnet with little leakage except close to the ends may be supposed to have point poles within itself a short distance back from the ends4 ,points1 ,consequent4 ,in a magnet with consequent poles1 the points where such poles are situated4 ,points1 ,corresponding4 ,in bound electrostatic charges the points of equal charges of opposite potentials2 the points at opposite extremities of electrostatic lines of force4 ,this definition implies that the bound charges shall be on equal facing areas of conductors1 as otherwise the spread or concentration of the lines of force would necessitate the use of areas of size proportionate to the spreading or concentrating of the lines of force4 ,at the same time it may figuratively be applied to these cases1 the penetration of the surface by a single line of force including the area fixed by its relation to the surrounding lines4 ,points1 ,isoelectric4 ,in electro-therapeutics1 points of equal potential in a circuit4 #dbc ,,standard ,,electrical ,,dictionary4 ,points of ,derivation4 ,the point where a single conductor branches into two or more conductors1 operating or acting in parallel with each other4 ,polar ,angle4 ,the angle subtended by one of the faces of the pole pieces of the field- magnet of a dynamo or motor4 ,the centre of the circle of the angle lies in the axis of the armature4 ,synonym--,angle of ,polar ,span4 ,polar ,extension4 ,an addition made of iron to the poles of magnets4 ,various forms have been experimented with4 ,the pole pieces of dynamo field magnets are polar extensions4 ,synonyms--,pole ,piece--,polar ,tips4 ,polarity1 ,diamagnetic4 ,the induced polarity of diamagnetic substances2 it is the reverse of paramagnetic polarity1 or of the polarity of iron4 ,a bar of diamagnetic material held parallel with the lines of force in a magnetic field has a like pole induced in the end nearest a given pole of the field magnet1 and vice versa4 ,this theory accounts for the repulsion by a magnet of a diamagnetic substance4 ,the existence of this polarity is rather an assumption4 ,it originated with ,faraday4 ,polarity1 ,paramagnetic4 ,the induced polarity of paramagnetic substances1 such as iron1 nickel1 or cobalt4 ,when such a substance is brought into a magnetic field the part nearest a specific pole of a magnet acquires polarity opposite to that of such pole and is thereby attracted4 ,another way of expressing it1 in which the existence of a pole in or near to the field is not implied1 is founded on the conventional direction of lines of force4 ,where these enter the substance a south pole is formed and where they emerge a north pole is formed4 ,such polarity tends always to be established in the direction of greatest length1 if the body is free to rotate4 #dbd ,,standard ,,electrical ,,dictionary4 ,polarization4 7a7 ,the depriving of a voltaic cell of its proper electro-motive force4 ,polarization may be due to various causes4 ,the solution may become exhausted1 as in a ,smee battery1 when the acid is saturated with zinc and thus a species of polarization follows4 ,but the best definition of polarization restricts it to the development of counter-electro-motive force in the battery by the accumulation of hydrogen on the negative 7carbon or copper7 plate4 ,to overcome this difficulty many methods are employed4 ,oxidizing solutions or solids are used1 such as solution of chromic acid or powdered manganese dioxide1 as in the ,bunsen and ,leclanch batteries respectively2 a roughened surface of platinum black is used1 as in the ,smee battery2 air is blown through the solution to carry off the hydrogen1 or the plates themselves are moved about in the solution4 7b7 ,imparting magnetization to a bar of iron or steel1 thus making a permanent magnet1 is the polarization of the steel of which it is made4 ,polarization may be permanent1 as in steel1 or only temporary1 as in soft iron4 7c7 ,the strain upon a dielectric when it separates two oppositely charged surfaces4 ,the secondary discharge of a ,leyden jar1 and its alteration in volume testify to the strain put upon it by charging4 7d7 ,the alteration of arrangement of the molecules of an electrolyte by a decomposing current4 ,all the molecules are supposed to be arranged with like ends pointing in the same direction1 positive ends facing the positively-charged plate and negative ends the negatively-charged one4 7e7 ,the production of counter-electro-motive force in a secondary battery1 or in any combination capable of acting as the seat of such counter-electro-motive force4 7,see ,battery1 ,secondary--,battery1 ,gas47 ,the same can be found often in organized cellular tissue such as that of muscles1 nerves1 or of plants4 ,if a current is passed through this in one direction1 it often establishes a polarization or potential difference that is susceptible of giving a return current in the opposite direction when the charging battery is replaced by a conductor4 ,polarization ,capacity4 ,a voltaic cell in use becomes polarized by its negative plate accumulating hydrogen1 or other cause4 ,this gradually gives the plate a positive value1 or goes to set up a counter-electro-motive force4 ,the quantity of electricity required to produce the polarization of a battery is termed its ,polarization ,capacity or ,capacity of ,polarization4 ,polarization of the ,medium4 ,the dielectric polarization1 q4 v41 of a dielectric1 implying the arrangement of its molecules in chains or filaments2 a term due to ,faraday4 ,he illustrated it by placing filaments of silk in spirits of turpentine1 and introduced into the liquid two conductors4 ,on electrifying one and grounding 7or connecting to earth7 the other one1 the silk filaments arranged themselves in a chain or string connecting the points of the conductors4 ,polar ,region4 ,that part of the surface of a magnet whence the internal magnetic lines emerge into the air4 7,s4 ,p4 ,thompson47 ,as such lines may emerge from virtually all parts of its surface1 the polar regions are indefinite areas1 and are properly restricted to the parts whence the lines emerge in greatest quantity4 ,polar ,span4 ,a proportion of the circle which represents the transverse section of the armature space between the pole pieces of the field magnet in a dynamo or motor2 it is the proportion which is filled by the faces of the pole pieces4 #dbe ,,standard ,,electrical ,,dictionary4 ,pole1 ,analogous4 ,the end of a crystal of a pyroelectric substance1 such as tourmaline1 which end when heated become positively electrified4 ,on reduction of temperature the reverse effect obtains4 ,pole1 ,antilogous4 ,the end of a crystal of a pyroelectric substance1 such as tourmaline1 which end1 while increasing in temperature1 becomes negatively electrified4 ,during reduction of its temperature the reverse effect obtains4 ,pole ,changer4 7a7 ,an automatic oscillating or vibrating switch or contact-breaker which in each movement reverses the direction of a current from a battery or other source of current of fixed direction1 as such current goes through a conductor4 7b7 ,a switch moved by hand which for each movement effects the above result4 ,pole1 ,negative4 7a7 ,in a magnet the south pole2 the pole into which the lines of force are assumed to enter from the air or outer circuit4 7b7 ,in a current generator the pole or terminal into which the current is assumed to flow from the external circuit4 ,it is the negatively charged terminal and in the ordinary voltaic battery is the terminal connected to the zinc or positive plate4 ,pole ,pieces4 ,the terminations of the cores of field or other electro-magnets1 or of permanent magnets4 ,these terminations are variously shaped1 sometimes being quite large compared to the core proper of the magnet4 ,they are calculated so as to produce a proper distribution of and direction of the lines of force from pole to pole4 ,as a general rule the active field should be of uniform strength and the pole pieces may be of contour calculated to attain this end4 ,pole1 ,positive4 7a7 ,in a magnet the north pole2 the pole from which lines of force are assumed to emerge into the air4 7b7 ,in a current generator the pole or terminal whence the current is assumed to issue into the outer circuit4 ,it is the positively charged terminal1 and in the ordinary voltaic battery is the terminal connected to the copper or carbon plate1 termed the negative plate4 ,poles4 7a7 ,the terminals of an open electric circuit1 at which there necessarily exists a potential difference1 produced by the generator or source of electro-motive force in the circuit4 7b7 ,the terminals of an open magnetic circuit2 the ends of a magnetized mass of steel1 iron or other paramagnetic substance4 7c7 ,the ends in general of any body or mass which show electric or magnetic properties more developed than those of the central sections of the body4 #dbf ,,standard ,,electrical ,,dictionary4 ,pole1 ,salient4 ,in dynamo and motor field magnets1 salient poles are those projecting from the base or main body of the field magnet1 as distinguished from consequent poles formed by coils wound on the main body itself4 ,fig4 #bfh4 ,,salient ,,poles ,,of ,,field ,,magnet4 ,poles1 ,compensating4 ,a device for avoiding the cross-magnetizing effect on the commutator core due to the lead of the brushes4 ,it consists in maintaining a small bar electro-magnet perpendicularly between the pole pieces4 ,this compensates the cross-magnetizing effect4 ,poles of ,intensity4 ,the locus of highest magnetic force on the earth's surface4 ,one such pole is in ,siberia1 another is about lat4 #eb ,n41 long4 #ib ,w4 ,transcriber's note3 #eb ,n41 long4 #ib ,w is about #bej miles ,northeast of ,winnipeg4 ,poles of ,verticity4 ,the magnetic poles of the earth4 7,see ,magnetic ,poles47 ,pole ,tips4 ,the extreme ends of the expanded poles of a field magnet4 ,in some machines some of the pole tips are made of cast iron1 to alter the distribution of the lines of force and resulting magnetic pull upon the armatures4 ,this is done to take off the weight of the armature from its bearings4 ,pole1 ,traveling4 ,a term applied to the poles produced in the action of a rotatory field1 whose poles constantly rotate around the circle of the field4 7,see ,field1 ,rotatory47 #dag ,,standard ,,electrical ,,dictionary4 ,porous ,cup4 ,a cup of pipe clay1 unglazed earthenware or other equivalent material used in voltaic cells to keep two liquids separate and yet to permit electrolysis and electrolytic conduction4 ,they are necessarily only an expedient1 as their porous nature permits considerable diffusion1 and were they not porous electrolytic action would be impossible4 ,synonym--,porous ,cell4 ,porret's ,phenomenon4 ,in electro-physiology1 an increase in the diameter of a nerve produced by the positive pole of a voltaic circuit1 when placed in contact with the tissue and near to the nerve in question1 the other pole being connected to a more or less remote part of the body4 ,portelectric ,railroad4 ,a railroad worked by solenoidal attraction1 the car forming the core of the solenoids4 ,it includes a series of solenoids or hollow coils of copper wire distributed all along the road and inclosing within themselves the track4 ,on this a cylindrical car with pointed ends moves on wheels4 ,current is supplied to the solenoid in advance of the car1 and attracts it4 ,as it advances it breaks the contacts of the attracting solenoid and turns the current into the one next in advance4 ,this operation is repeated as the car advances4 ,the solenoids are placed close together1 each including in the trial track #fcj turns of ,no4 #ad copper wire4 ,the car was of wrought iron1 #ab feet long1 #aj inches in diameter and weighing #ejj lbs4 ,it was proposed to employ the system for transportation of mail matter and similar uses4 ,position ,finder4 ,an instrument for determining the position of objects which are to be fired at from forts4 ,it is designed for use from forts situated on the water4 ,fiske's position finder may be thus generally described4 ,on a chart the channel is divided into squares1 and the position finder determines the square in which a vessel lies4 ,for each square the direction and elevation of the guns is calculated beforehand4 ,the enemy can therefore be continuously located and fired at1 although from smoke or other cause the object may be quite invisible to the gunner4 ,it comprises two telescopes situated at distant extremities of as long a base line as is obtainable4 ,these telescopes are kept directed upon the object by two observers simultaneously4 ,the observers are in constant telephonic communication4 ,as each telescope moves1 it carries a contact over an arc of conducting material4 ,below each telescope is an arm also moving over an arc of conducting material4 ,these arcs enter into a ,wheatstone bridge and are so connected that when the arm and the distant telescope are at the same angle or parallel a balance is obtained4 ,thus each observer has the power of establishing a balance4 ,a chart is provided for each of them1 and over it the arm connected with the distant telescope and an arm or indicator attached to the telescope at that station move so that as long as both telescopes point at the object and each observer maintains the electric balance1 the intersection of the arms shows the position on the chart4 ,the ,position ,finder is a simplification and amplification of the ,range ,finder1 q4 v4 ,in practice the observers may be placed far from the forts1 and may telephone their observations thereto4 ,it has been found accurate within one-third of one per cent4 #dbh ,,standard ,,electrical ,,dictionary4 ,positive ,direction4 ,the direction which lines of force are assumed to take in the air or outer circuit from a positive to a negative region4 ,it applies to electrostatic1 to magnetic and to electro-magnetic lines of force4 ,positive ,electricity4 ,the kind of electricity with which a piece of glass is charged when rubbed with silk2 vitreous electricity4 ,in a galvanic cell the surface of the copper or carbon plate is charged with positive electricity4 7,see ,electrostatic ,series47 ,according to the single fluid theory positive electrification consists in a surplus of electricity4 ,transcriber's note3 ,positive electricity is a deficiency of electrons4 ,post ,office4 adj4 ,many pieces of electric apparatus of ,english manufacture are thus qualified1 indicating that they are of the pattern of the apparatus used by the ,british ,post ,office in its telegraph department4 ,potential4 ,potential in general may be treated as an attribute of a point in space1 and may express the potential energy which a unit mass would have if placed at that point4 ,this conception of potential is that of a property attributable to a point in space1 such that if a unit mass were placed there the forces acting upon it would supply the force factor of energy1 while the body would supply the mass factor4 ,this property is expressible in units1 which produce1 if the supposed mass is a unit mass1 units of work or energy1 but potential itself is neither4 ,thus taking gravitation1 a pound mass on the surface of the earth 7assuming it to be a sphere of #d1jjj miles radius7 would require the expenditure of #ba1abj1jjj foot pounds to remove it to an infinite distance against gravity4 ,the potential of a point in space upon the surface of the earth is therefore negative and is represented by -#ba1abj1jjj99cb4b foot poundals 7#cb4b acceleration of gravity74 7,see ,poundal47 ,in practice and conventionally all points on the earth's surface are taken as of zero potential4 ,transcriber's note2 #ba1abj1jjj foot pounds is about #h ,k,wh4 #dbi ,,standard ,,electrical ,,dictionary4 ,potential1 ,absolute4 ,the absolute electrical potential at a point possesses a numerical value and measures the tendency which the existing electric forces would have to drive an electrified particle away from or prevent its approach to the point1 if such a particle1 one unit in quantity1 were brought up to or were situated at that point4 ,it is numerically equal to the number of ergs of work which must be done to bring a positive unit of electricity from a region where there is absolutely no electric force up to the point in question4 7,daniell47 ,two suppositions are included in this4 ,the region where there is an electric force has to be and only can be at an infinite distance from all electrified bodies4 ,the moving of the particle must take place without any effect upon the distribution of electricity on other particles4 ,potential1 ,constant4 ,unchanging potential or potential difference4 ,the ordinary system of incandescent lighting is a constant potential system1 an unvarying potential difference being maintained between the two leads1 and the current varying according to requirements4 ,potential ,difference1 ,electric4 ,if of any two points the absolute potentials are determined1 the difference between such two expresses the potential difference4 ,numerically it expresses the quantity of work which must be done to remove a unit of electricity from one to the other against electric repulsion1 or the energy which would be accumulated in moving it the other way4 ,a positively charged particle is driven towards the point of lower potential4 ,a negatively charged body is driven in the reverse direction4 ,potential ,difference1 ,electro-motive4 ,a difference of potential in a circuit1 or in part of a circuit1 which difference produces or is capable of producing a current1 or is due to the flow of such current4 ,it may be expressed as the fall in potential or the electro-motive force included between any two points on a circuit4 ,the current in an active circuit is due to the total electro-motive force in the circuit4 ,this is distributed through the circuit in proportion to the resistance of its parts4 ,owing to the distribution of electro-motive force throughout a circuit including the generator1 the terminals of a generator on closed circuit may show a difference of potential far lower than the electro-motive force of the generator on closed circuit4 ,hence potential difference in such a case has been termed available electro-motive force4 ,potential1 ,electric ,absolute4 ,the mathematical expression of a property of a point in space1 measuring the tendency which existing electric forces would have to drive an electrified unit particle away from or prevent its approach to the point in question1 according to whether the point was situated at or was at a distance from the point in question4 ,potential is not the power of doing work1 although1 as it is expressed always with reference to a unit body1 it is numerically equal to the number of ergs of work which must be done in order to bring a positive unit of electricity from a region where there is no electric force--which is a region at an infinite distance from all electrified bodies--up to the point in question4 ,this includes the assumption that there is no alteration in the general distribution of electricity on neighboring bodies4 7,daniell47 ,in practice the earth is arbitrarily taken as of zero electric potential4 #dcj ,,standard ,,electrical ,,dictionary4 ,potential1 ,fall of4 ,the change in potential between any two points on an active circuit4 ,the change in potential due to the maintenance of a current through a conductor4 ,the fall in potential multiplied by the current gives work or energy units4 ,the fall of potential in a circuit and its subsequent raising by the action of the generator is illustrated by the diagram of a helix4 ,in it the potential fall in the outer circuit is shown by the descent of the helix4 ,this represents at once the outer circuit and the fall of potential in it4 ,the vertical axis represents the portion of the circuit within the battery or generator in which the potential by the action of the generator is again raised to its original height4 ,in a circuit of even resistance the potential falls evenly throughout it4 ,a mechanical illustration of the relation of fall of potential to current is shown in the cut ,fig4 #bfi4 ,a vertical wire is supposed to be fixed at its upper end and a lever arm and cord at its lower end1 with weight and pulley imparts a torsional strain to it4 ,the dials and indexes show a uniform twisting corresponding to fall of potential4 ,for each unit of length there is a definite loss of twisting1 corresponding to fall of potential in a unit of length of a conductor of uniform resistance4 ,the total twisting represents the total potential difference4 ,the weight sustained by the twisting represents the current maintained by the potential difference4 ,for a shorter wire less twisting would be needed to sustain the weight1 as in a shorter piece of the conductor less potential difference would be needed to maintain the same current4 ,fig4 #bfi4 ,,mechanical ,,illustration ,,of ,,fall ,,of ,,potential ,,and ,,current ,,strength4 #dca ,,standard ,,electrical ,,dictionary4 ,fig4 #bgj4 ,,illustration ,,of ,,the ,,fall ,,and ,,redevelopment ,,of ,,potential ,,in ,,an ,,electric ,,circuit4 ,the fall of potential in a circuit in portions of it is proportional to the resistance of the portions in question4 ,this is shown in the diagram4 ,the narrow lines indicate high and the broad lines low resistance4 ,the fall in different portions is shown as proportional to the resistance of each portion4 ,fig4 #bga4 ,,diagram ,,of ,,fall ,,of ,,potential ,,in ,a ,,conductor ,,of ,,uneven ,,resistance4 ,potential1 ,magnetic4 ,the magnetic potential at any point of a magnetic field expresses the work which would be done by the magnetic forces of the field on a positive unit of magnetism as it moves from that point to an infinite distance therefrom4 ,the converse applies to a negative unit4 ,it is the exact analogue of absolute electric potential4 ,the potential at any point due to a positive pole m at a distance r is m_/r24 that due to a negative pole - m at a distance r' is equal to -m_/r'24 that due to both is equal to m_/r - m_/r' or m7#a_/r - #a_/r'74 ,like electric potential and potential in general1 magnetic potential while numerically expressing work or energy is neither1 although often defined as such4 #dcb ,,standard ,,electrical ,,dictionary4 ,potential1 ,negative4 ,the reverse of positive potential4 7,see ,potential1 ,positive47 ,potential1 ,positive4 ,in general the higher potential4 ,taking the assumed direction of lines of force1 they are assumed to be directed or to move from regions of positive to regions of negative potential4 ,the copper or carbon plate of a voltaic battery is at positive potential compared to the zinc plate4 ,potential1 ,unit of ,electric4 ,the arbitrary or conventional potential--or briefly1 the potential of a point in an electric field of force--is1 numerically1 the number of ergs of work necessary to bring a unit of electricity up to the point in question from a region of nominal zero potential--i4 e41 from the surface of the earth4 7,daniell47 ,this would give the erg as the unit of potential4 ,potential1 ,zero4 ,the potential of the earth is arbitrarily taken as the zero of electric potential4 ,the theoretical zero is the potential of a point infinitely distant from all electrified bodies4 ,fig4 #bgb4 ,,diagram ,,of ,,potentiometer ,,connections4 ,potentiometer4 ,an arrangement somewhat similar to the ,wheatstone ,bridge for determining potential difference1 or the electro-motive force of a battery4 ,in general principle connection is made so that the cell under trial would send a current in one direction through the galvanometer4 ,another battery is connected1 and in shunt with its circuit the battery under trial and its galvanometer are connected1 but so that its current is in opposition4 ,by a graduated wire1 like that of a meter bridge1 the potential of the main battery shunt can be varied until no current passes4 ,this gives the outline of the method only4 #dcc ,,standard ,,electrical ,,dictionary4 ,in the cut ,a ,b is the graduated potentiometer wire through which a current is passed in the direction of the arrow4 ,e is the battery under trial1 placed in opposition to the other current1 with a galvanometer next it4 ,under the conditions shown1 if the galvanometer showed no deflection1 the ,e4 ,m4 ,f4 of the battery would be to the ,e4 ,m4 ,f4 between the ends of the potentiometer wire1 #a 4 4 4 4 4#aj1 as #a4e the distance between the points of connection1 ,a and ,d of the battery circuit1 is to #aj1 the full length of the potentiometer wire4 ,poundal4 ,the ,british unit of force2 the force which acting on a mass of one pound for one second produces an acceleration of one foot4 ,transcriber's note3 ,the force which acting on a mass of one pound produces an acceleration of ,,one ,,foot ,,per ,,second ,,per ,,second4 ,power4 ,activity2 the rate of activity1 of doing work1 or of expending energy4 ,the practical unit of electric power is the volt-ampere or watt1 equal to #a;,e#g ergs per second4 ,the kilowatt1 one thousand watts or volt-amperes1 is a frequently adopted unit4 ,power1 ,electric4 ,as energy is the capacity for doing work1 electric energy is represented by electricity in motion against a resistance4 ,this possesses a species of inertia1 which gives it a species of kinetic energy4 ,to produce such motion1 electro- motive force is required4 ,the product of ,e4 ,m4 ,f4 by quantity is therefore electric energy4 7,see ,energy1 ,electric47 ,generally the rate of energy or power is used4 ,its dimensions are 7 7 7,m4#e7997,l4#e7 7 _/ ,t 7 99 7 7 7,m4#e7 997,l#a4e7 7_/7 ,t#b7 7 7intensity or current rate7 99 7electro-motive force or potential7 7,m 99 7,l#b7 7 _/ 7,t#c71 which are the dimensions of rate of work or activity4 ,the practical unit of electric rate of energy or activity is the volt-ampere or watt4 ,by ,ohm's law1 q4 v41 we have ,c ,e_/,r 7,c current2 ,e potential difference or electro-motive force2 ,r resistance47 ,the watt by definition ,c99,e4 ,by substitution from ,ohm's formula we deduce for it the following values3 77,c#b7 99 ,r7 and 77,e#b7 _/,r74 ,from these three expressions the relations of electric energy to ,e4,m4,f41 ,resistance1 and ,current can be deduced4 ,power of ,periodic ,current4 ,the rate of energy in a circuit carrying a periodic current4 ,in such a circuit the electro-motive force travels in advance of the current it produces on the circuit4 ,consequently at phases or intervals where1 owing to the alternations of the current1 the current is at zero1 the electro-motive force may be quite high4 ,at any time the energy rate is the product of the electro-motive force by the amperage4 ,to obtain the power or average rate of energy1 the product of the maximum electro-motive force and maximum current must be divided by two and multiplied by the cosine of the angle of lag1 which is the angle expressing the difference of phase4 ,transcriber's note2 ,the voltage phase will lead if the load is inductive4 ,the current phase will lead if the load is capacitive4 ,capacitors or inductors may be introduced into power lines to correct the phase offset introduced by customer loads4 #dcd ,,standard ,,electrical ,,dictionary4 ,pressel4 ,a press-button often contained in a pear-shaped handle1 arranged for attachment to the end of a flexible conductor1 so as to hang thereby4 ,by pressing the button a bell may be rung1 or a distant lamp may be lighted4 ,pressure4 ,force or stress exerted directly against any surface4 ,its dimensions are force_/area or 77,m99,l7_/7,t#b77 _/ 7,l#b7 ,m_/7,l99 7,t#b774 ,pressure1 ,electric4 ,electro-motive force or potential difference2 voltage4 ,an expression of metaphorical nature1 as the term is not accurate4 ,pressure1 ,electrification by4 ,a crystal of ,iceland spar 7calcium carbonate7 pressed between the fingers becomes positively electrified and remains so for some time4 ,other minerals act in a similar way4 ,dissimilar substances pressed together and suddenly separated carry off opposite charges4 ,this is really contact action1 not pressure action4 ,primary4 ,a term used to designate the inducing coil in an induction coil or transformer2 it is probably an abbreviation for primary coil4 ,primary ,battery4 ,a voltaic cell or battery generating electric energy by direct consumption of material1 and not regenerated by an electrolytic process4 ,the ordinary voltaic cell or galvanic battery is a primary battery4 ,prime4 vb4 ,to impart the first charge to one of the armatures of a ,holtz or other influence machine4 ,fig4 #bgc4 ,,prime ,,conductor ,,and ,,proof ,,plane4 #dce ,,standard ,,electrical ,,dictionary4 ,prime ,conductor4 ,a metal or metal coated sphere or cylinder or other solid with rounded ends mounted on insulating supports and used to collect electricity as generated by a frictional electric machine4 ,according to whether the prime conductor or the cushions are grounded positive or negative electricity is taken from the ungrounded part4 ,generally the cushions are grounded1 and the prime conductor yields positive electricity4 ,probe1 ,electric4 ,a surgeon's probe1 designed to indicate by the closing of an electric circuit the presence of a bullet or metallic body in the body of a patient4 ,two insulated wires are carried to the end where their ends are exposed1 still insulated from each other4 ,in probing a wound for a bullet if the two ends touch it the circuit is closed and a bell rings4 ,if a bone is touched no such effect is produced4 ,the wires are in circuit with an electric bell and battery4 ,projecting ,power of a ,magnet4 ,the power of projecting its lines of force straight out from the poles4 ,this is really a matter of magnetic power1 rather than of shape of the magnet4 ,in electromagnets the custom was followed by making them long to get this effect4 ,such length was really useful in the regard of getting room for a sufficient number of ampere turns4 #dcf ,,standard ,,electrical ,,dictionary4 ,fig4 #bgd4 ,,prony ,,brake4 ,prony ,brake4 ,a device for measuring the power applied to a rotating shaft4 ,it consists of a clamping device to be applied more or less rigidly to the shaft or to a pulley upon it4 ,to the clamp is attached a lever carrying a weight4 ,the cut shows a simple arrangement1 the shaft ,a carries a pulley ,b to which the clamp ,b#a ,b#b is applied4 ,the nuts ,c#a ,c#b are used for adjustment4 ,a weight is placed in the pan ,e attached to the end of the lever ,d4 ,the weight and clamp are so adjusted that the lever shall stand horizontally as shown by the index ,e4 ,if we call r the radius of the pulley and ,f the friction between its surface and the clamp1 it is evident that r ,f1 the moment of resistance to the motion of the pulley1 is equal to the weight multiplied by its lever arm or to ,w99,r1 where ,w indicates the weight and ,r the distance of its point of application from the centre of the pulley or r99,f ,r99,w4 ,the work represented by this friction is equal to the distance traveled by the surface of the wheel multiplied by the frictional resistance1 or is #b99,,pi99r99n99,f1 in which n is the number of turns per minute4 ,but this is equal to #b99,,pi99,r99,w4 ,these data being known1 the power is directly calculated therefrom in terms of weight and feet per minute4 ,proof-plane4 ,a small conductor1 usually disc shaped1 carried at the end of an insulating handle4 ,it is used to collect electricity by contact1 from objects electrostatically charged4 ,the charge it has received is then measured 7see ,torsion ,balance7 or otherwise tested4 7,see ,prime ,conductor47 ,proof-sphere4 ,a small sphere1 coated with gold-leaf or other conductor1 and mounted on an insulated handle4 ,it is used instead of a proof-plane1 for testing bodies whose curvature is small4 ,fig4 #bge4 ,,box ,,bridge4 #dcg ,,standard ,,electrical ,,dictionary4 ,proportionate ,arms4 ,in general terms the arms of a ,wheatstone bridge whose proportion has to be known to complete the measurement4 ,there is a different system of naming them4 ,some designate by this title the two arms in parallel with each other branching at and running from one end of the bridge to the two galvanometer connections4 ,in the cut of the ,box ,bridge1 ,a ,c and ,a ,b are the proportionate arms4 ,the third arm is then termed the ,rheostat arm4 7,stewart ,gee47 ,others treat as proportionate arms the two side members of the bridge in parallel with the unknown resistance and third or rheostat arm4 ,synonym--,ratio ,arms4 ,prostration1 ,electric4 ,too great exposure to the voltaic arc in its more powerful forms causes symptoms resembling those of sunstroke4 ,the skin is sometimes affected to such a degree as to come off after a few days4 ,the throat1 forehead and face suffer pains and the eyes are irritated4 ,these effects only follow exposure to very intense sources of light1 or for very long times4 ,transcriber's note3 ,arcs emit ultraviolet rays4 ,protector1 ,comb4 ,a lightning arrester1 q4 v41 comprising two toothed plates nearly touching each other4 ,protector1 ,electric4 ,a protective device for guarding the human body against destructive or injurious electric shocks4 ,in one system1 ,delany's1 the wrists and ankles are encircled by conducting bands which by wires running along the arms1 back and legs are connected4 ,a discharge it is assumed received by the hands will thus be short circuited around the body and its vital organs4 ,india rubber gloves and shoe soles have also been suggested2 the gloves are still used to some extent4 ,pull4 ,a switch for closing a circuit when pulled4 ,it is used instead of a push button1 q4v41 in exposed situations1 as its contacts are better protected than those of the ordinary push button4 ,pump1 ,geissler4 ,a form of mercurial air pump4 ,it is used for exhausting ,geissler tubes1 incandescent lamp bulbs and similar purposes4 ,referring to the cut1 ,a is a reservoir of mercury with flexible tube ,c connected to a tube at its bottom1 and raised and lowered by a windlass b1 the cord from which passes over a pulley a4 ,when raised the mercury tends to enter the chamber ,b1 through the tube ,t4 ,an arrangement of stopcocks surmounts this chamber1 which arrangement is shown on a larger scale in the three figures ,x1 ,y and ,z4 ,to fill the bulb ,b1 the cocks are set in the position ,z2 n is a two way cock and while it permits the escape of air below1 it cuts off the tube1 rising vertically from it4 ,this tube1 d in the full figure connects with a vessel o1 pressure gauge p1 and tube c1 the latter connecting with the object to be exhausted4 ,the bulb ,b being filled1 the cock m is closed1 giving the position ,y and the vessel ,a is lowered until it is over #cj inches below ,b4 #dch ,,standard ,,electrical ,,dictionary4 ,this establishes a ,torricellian vacuum in ,b4 ,the cock n is now turned1 giving the position ,x1 when air is at once exhausted from the vessel connected to ,c4 ,this process is repeated until full exhaustion is obtained4 ,in practice the first exhaustion is often effected by a mechanical pump4 ,by closing the cock on the outlet tube c but little air need ever find its way to the chambers o and ,b4 ,fig4 #bgf4 ,,geissler ,,air ,,pump4 #dci ,,standard ,,electrical ,,dictionary4 ,pumping4 ,in incandescent lamps a periodical recurring change in intensity due to bad running of the dynamos1 or in arc lamps to bad feeding of the carbons4 ,fig4 #bgg4 ,,sprengel ,,air ,,pump4 ,pump1 ,sprengel4 ,a form of mercurial air pump4 ,a simple form is shown in the cut4 ,mercury is caused to flow from the funnel ,a1 through c d to a vessel ,b4 ,a side connection x leads to the vessel ,r to be exhausted4 ,as the mercury passes x it breaks into short columns1 and carries air down between them1 in this way exhausting the vessel ,r4 ,in practice it is more complicated4 ,it is said to give a better vacuum than the ,sprengel pump1 but to be slower in action4 #ddj ,,standard ,,electrical ,,dictionary4 ,pump1 ,swinburne4 ,a form of mechanical air pump for exhausting incandescent lamp bulbs4 ,referring to the cut1 ,a is a bulb on the upper part of a tube ,g2 above ,a are two other bulbs ,c and ,d4 ,from the upper end a tube runs to the bulb ,e4 ,through the cock ,l1 and tube ,f connection is made with a mechanical air pump4 ,the tube ,h leads to a drying chamber ,i1 and by the tube ,j connects with the lamp bulbs or other objects to be exhausted4 ,the tube ,g enters the bottle ,b through an airtight stopper1 through which a second tube with stopcock ,k passes4 ,in use a vacuum is produced by the mechanical pumps1 exhausting the lamp bulbs to a half inch and drawing up the mercury in ,g4 ,the bent neck in the bulb ,e1 acts with the bulb as a trap to exclude mercury from ,f4 ,when the mechanical pumps have produced a vacuum equal to one half inch of mercury1 the cock ,l is closed and ,k is opened1 and air at high pressure enters4 ,this forces the mercury up to the vessel ,d1 half filling it4 ,the high pressure is now removed and the mercury descends4 ,the valve in ,d closes it as the mercury falls to the level ,g4 ,further air from the lamps enters ,a1 and by repetition of the ascent of the mercury1 is expelled1 through ,d4 ,the mercury is again lowered1 producing a further exhaustion1 and the process is repeated as often as necessary4 ,fig4 #bgh4 ,,swinburne',s ,,air ,,pump4 ,push-,button4 ,a switch for closing a circuit by means of pressure applied to a button4 ,the button is provided with a spring1 so that when pushed in and released it springs back4 ,thus the circuit is closed only as long as the button is pressed4 ,the electric connection may be made by pressing together two flat springs1 each connected to one of the wires1 or by the stem of the button going between two springs1 not in contact1 forcing them a little apart to secure good contact1 and thereby bridging over the space between them4 #dda ,,standard ,,electrical ,,dictionary4 ,pyro-electricity4 ,a phenomenon by which certain minerals when warmed acquire electrical properties4 7,ganot47 ,the mineral tourmaline exhibits it strongly4 ,it was originally observed in this mineral which was found to first attract and then to repel hot ashes4 ,the phenomenon lasts while any change of temperature within certain limits is taking place4 ,in the case of tourmaline the range is from about #aj ,c4 7#ej ,f47 to #aej ,c4 7#cjb ,f47 ,above or below this range it shows no electrification4 ,the effect of a changing of temperature is to develop poles1 one positive and the other negative4 ,as the temperature rises one end is positive and the other negative2 as the temperature becomes constant the polarity disappears2 as the temperature falls the poles are reversed4 ,if a piece of tourmaline excited by pyro-electricity is broken1 its broken ends develop new poles exactly like a magnet when broken4 ,the following minerals are pyro-electric3 ,boracite1 topaz1 prehnite1 zinc silicate1 scolezite1 axenite4 ,the following compound substances are also so3 ,cane sugar1 sodium- ammonium racemate and potassium tartrate4 ,the list might be greatly extended4 ,the phenomenon can be illustrated by sifting through a cotton sieve upon the excited crystal1 a mixture of red lead and flowers of sulphur4 ,by the friction of the sifting these become oppositely electrified2 the sulphur adheres to the positively electrified end1 and the red lead to the negatively electrified end4 7,see ,analogous ,pole-,antilogous ,pole47 ,pyromagnetic ,motor4 ,a motor driven by the alternation of attraction and release of an armature or other moving part1 as such part or a section of it is rendered more or less paramagnetic by heat4 ,thus imagine a cylinder of nickel at the end of a suspension rod1 so mounted that it can swing like a pendulum4 ,a magnet pole is placed to one side to which it is attracted4 ,a flame is placed so as to heat it when in contact with the magnet pole4 ,this destroys its paramagnetism and it swings away from the magnet and out of the flame4 ,it cools1 becomes paramagnetic1 and as it swings back is reattracted1 to be again released as it gets hot enough4 ,this constitutes a simple motor4 ,a rotary motor may be made on the same lines4 ,nickel is particularly available as losing its paramagnetic property easily4 #ddb ,,standard ,,electrical ,,dictionary4 ,various motors have been constructed on this principle1 but none have attained any practical importance4 ,owing to the low temperature at which it loses its paramagnetic properties nickel is the best metal for paramagnetic motors4 ,in ,edison's motor1 between the pole pieces of an electro-magnet a cylinder made up of a bundle of nickel tubes is mounted1 so as to be free to rotate4 ,a screen is placed so as to close or obstruct the tubes farthest from the poles4 ,on passing hot air or products of combustion of a fire or gas flame through the tubes1 the unscreened ones are heated most and lose their paramagnetism4 ,the screened tubes are then attracted and the armature rotates1 bringing other tubes under the screen1 which is stationary4 ,then the attracted tubes are heated while the others cool1 and a continuous rotation is the result4 ,fig4 #bgi4 ,,edison',s ,,pyromagnetic ,,motor4 ,pyromagnetic ,generator4 ,a current generator producing electric energy directly from thermal energy by pyromagnetism4 ,edison's pyromagnetic generator has eight electro-magnets1 lying on eight radii of a circle1 their poles facing inward and their yokes vertical4 ,only two are shown in the cut4 ,on a horizontal iron disc are mounted eight vertical rolls of corrugated nickel representing armatures4 ,on each armature a coil of wire1 insulated from the nickel by asbestus is wound4 ,the coils are all in series1 and have eight connections with a commutator as in a drum armature4 ,there are two main divisions to the commutator4 ,each connects with an insulated collecting ring1 and the commutator and collecting rings are mounted on a spindle rotated by power4 ,below the circle of vertical coils is a horizontal screen1 mounted on the spindle and rotating with it4 ,a source of heat1 or a coal stove is directly below the machine and its hot products of combustion pass up through the coils1 some of which are screened by the rotating screen4 ,the effect is that the coils are subjecting to induction owing to the change in permeability of the nickel cores1 according as they are heated1 or as they cool when the screen is interposed4 ,the two commutator segments are in constant relation to the screen1 and current is collected therefrom and by the collecting rings is taken to the outside circuit4 #ddc ,,standard ,,electrical ,,dictionary4 ,pyromagnetism4 ,the development of new magnetic properties or alteration of magnetic sensibility in a body by heat4 ,nickel and iron are much affected as regards their paramagnetic power by rise of temperature4 ,fig4 #bhj4 ,,pyromagnetic ,,generator4 ,pyrometer1 ,siemens' ,electric4 ,an instrument for measuring high temperatures by the variations in electric resistance in a platinum wire exposed to the heat which is to be measured4 ,q4 ,symbol for electric quantity4 ,quad4 7a7 ,a contraction for quadrant1 used as the unit of inductance2 the henry4 7b7 ,a contraction for quadruplex in telegraphy4 ,transcriber's note3 ,a modern use of quad is a unit of energy equal to #a;,e#ae 7one quadrillion7 ,,btu1 or #a4jee;,e#ah joules4 ,global energy production in #bjjd was #ddf quad4 ,quadrant4 ,a length equal to an approximate earth quadrant1 equal to #a;,e#i centimeters4 ,it has been used as the name for the unit of inductance1 the henry1 q4 v4 ,synonym--,standard ,quadrant4 #ddd ,,standard ,,electrical ,,dictionary4 ,quadrant1 ,legal4 ,the accepted length of the quadrant of the earth1 #i4igh;,e#h instead of #a;,e#i centimeters2 or to #i1igh kilometers instead of #aj1jjj kilometers4 ,quadrature4 ,waves or periodic motions the angle of lag of one of which1 with reference to one in advance of it1 is #ij1 are said to be in quadrature with each other4 ,transcriber's note3 ,if the voltage and current of a power line are in quadrature1 the power factor is zero 7cos7#ij7 #j7 and no real power is delivered to the load4 ,qualitative4 ,involving the determination only of the presence or absence of a substance or condition1 without regard to quantity4 ,thus a compass held near a wire might determine qualitatively whether a current was passing through the wire1 but would not be sufficient to determine its quantity4 7,see ,quantitative47 ,quality of ,sound4 ,the distinguishing characteristic of a sound other than its pitch2 the timbre4 ,it is due to the presence with the main or fundamental sound of other minor sounds called overtones1 the fundamental note prevailing and the other ones being superimposed upon it4 ,the human voice is very rich in overtones2 the telephone reproduces these1 thus giving the personal peculiarities of every voice4 ,synonym--,timbre4 ,quantitative4 ,involving the determination of quantities4 ,thus a simple test would indicate that a current was passing through a wire4 ,this would be a qualitative test4 ,if by proper apparatus the exact intensity of the current was determined1 it would be a quantitative determination4 7,see ,qualitative47 ,quantity4 ,this term is used to express arrangements of electrical connections for giving the largest quantity of current1 as a quantity armature1 meaning one wound for low resistance4 ,a battery is connected in quantity when the cells are all in parallel4 ,it is the arrangement giving the largest current through a very small external resistance4 ,the term is now virtually obsolete 7,daniell72 in surface1 in parallel1 or in multiple arc is used4 ,quantity1 ,electric4 ,electricity may be measured as if it were a compressible gas1 by determining the potential it produces when stored in a defined recipient4 ,in this way the conception of a species of quantity is reached4 ,it is also measured as the quantity of current passed by a conductor4 ,thus a body whose surface is more or less highly charged with electricity1 is said to hold a greater or less quantity of electricity4 ,it may be defined in electrostatic or electro-magnetic terms4 7,see ,quantity1 ,electrostatic--,quantity1 ,electro-magnetic47 #dde ,,standard ,,electrical ,,dictionary4 ,quantity4 ,electro-magnetic4 ,quantity is determined electro-magnetically by the measurement of current intensity for a second of time3 its dimensions are therefore given by multiplying intensity or current strength by time4 ,the dimensions of intensity are 7 7,m4#e7 99 7,l4#e7 7 _/ ,t therefore the dimensions of electro-magnetic quantity are 7 7 7,m4#e7 99 7,l4#e7 7 _/ ,t 7 99 ,t 7 7,m4#e7 99 7,l4#e7 7 ,quantity1 ,electro-magnetic1 ,practical ,unit of4 ,the quantity of electricity passed by a unit current in unit time2 the quantity passed by one ampere in one second2 the coulomb4 ,it is equal to #c;,e#i electrostatic absolute units of quantity and to #j4a of the electro- magnetic absolute unit of quantity4 ,one coulomb is represented by the deposit of 4#jjaaahae gram1 or 4#jagbec grain of silver1 4#jjjcbiei gram1 or 4#jjehjd grain of copper1 4#jjjccib gram1 or 4#jjebcb grain of zinc4 ,if water is decomposed by a current each coulomb is represented by the cubic centimeters of the mixed gases 7hydrogen and oxygen7 given by the following formula4 7 #j4agch 99 #gf 99 7#bgc ,c 7 7 _/ 7 h 99 #bgc 7 in which ,c is the temperature of the mixed gases in degree centigrade and h is the pressure in centimeters of mercury column2 or by 7 #j4jajeh 99 #cj 7#dia ,f - #cb7 7 _/ 7h 99 #dia 7 for degrees ,fahrenheit and inches of barometer4 ,transcriber's note3 #f4bdaejifbiaebfe;,e#ah electrons is one coulomb4 ,quantity1 ,electrostatic4 ,quantity is determined electro-statically by the repulsion a charge of given quantity exercises upon an identical charge at a known distance4 ,the force evidently varies with the product of the two quantities1 and by the law of radiant forces also inversely with the square of the distance4 ,the dimensions given by these considerations is ,q 99 ,q_/7,l99,l74 ,this is the force of repulsion4 ,the dimensions of a force are 7,m 99 ,l7 _/7,t#b74 ,equating these two expressions we have3 7,q#b7_/7,l#b7 7,m99,l7_/7,t#b7 or ,q 77,m4#e7997,l#a4e77 _/ ,t which are the dimensions of electrostatic quantity4 ,quantity1 ,meter4 ,an electric meter for determining the quantity of electricity which passes through it1 expressible in coulombs or ampere hours4 ,all commercial meters are quantity meters4 #ddf ,,standard ,,electrical ,,dictionary4 ,quartz4 ,a mineral1 silica1 ,si,o#b4 ,it has recently been used by ,c4 ,v4 ,boys and since by others in the making of filaments for torsion suspensions4 ,the mineral is melted1 while attached to an arrow or other projectile4 ,it is touched to another piece of quartz or some substance to which it adheres and the arrow is fired off from the bow4 ,a very fine filament of surpassingly good qualities for galvanometer suspension filaments is produced4 ,as a dielectric it is remarkable in possessing but one-ninth the residual capacity of glass4 ,quicking4 ,the amalgamating of a surface of a metallic object before silver plating4 ,it secures better adhesion of the deposit4 ,it is executed by dipping the article into a solution of a salt of mercury4 ,a solution of mercuric nitrate #a part1 in water #ajj parts1 both by weight1 is used4 ,r4 7a7 ,abbreviation and symbol for ,reamur1 as #aj ,r41 meaning #aj by the ,reamur thermometer4 7,see ,reamur ,scale47 7b7 ,symbol for resistance1 as in the expression of ,ohm's ,law ,c,e_/,r4 7rho1 ,greek r7 ,symbol for specific resistance4 ,racing of ,motors4 ,the rapid acceleration of speed of a motor when the load upon it is removed4 ,it is quickly checked by counter-electro-motive force4 7,see ,motor1 ,electric47 ,radian4 ,the angle whose arc is equal in length to the radius2 the unit angle4 ,radiant ,energy4 ,energy1 generally existing in the luminiferous ether1 kinetic and exercised in wave transmission1 and rendered sensible by conversion of its energy into some other form of energy1 such as thermal energy4 ,if the ether waves are sufficiently short and not too short1 they directly affect the optic nerve and are known as light waves2 they may be so short as to be inappreciable by the eye1 yet possess the power of determining chemical change1 when they are known as actinic waves2 they may be also so long as to be inappreciable by the eye1 when they may be heat-producing waves1 or obscure waves4 ,other forms of energy may be radiant1 as sound energy dispersed by the air1 and gravitational energy1 whose connection with the ether has not yet been demonstrated4 ,radiation4 ,the traveling or motion of ether waves through space4 ,transcriber's note3 ,the modern term corresponding to this definition is photons4 ,the modern concept of radiation also includes particles-- neutrons1 protons1 alpha 7helium7 and beta 7electrons7 rays and other exotic items4 ,radicals4 ,a portion of a molecule1 possessing a free bond and hence free to combine directly4 ,a radical never can exist alone1 but is only hypothetical4 ,an atom is a simple radical1 an unsaturated group of atoms is a compound radical4 #ddg ,,standard ,,electrical ,,dictionary4 ,radiometer4 ,an instrument consisting of four vanes poised on an axis so as to be free to rotate1 and contained in a sealed glass vessel almost perfectly exhausted4 ,the vanes of mica are blackened on one side4 ,on exposure to light or a source of heat 7ether waves7 the vanes rotate4 ,the rotation is due to the beating back and forth of air molecules from the surface of the vanes to the inner surface of the glass globe4 ,radiometer1 ,electric4 ,a radiometer in which the motion of the molecules of air necessary for rotation of the vane is produced by electrification and not by heating4 ,radio-micrometer4 ,an instrument for detecting radiant energy of heat or light form4 ,it consists of a minute thermopile with its terminals connected by a wire1 the whole suspended between the poles of a magnet4 ,a minute quantity of heat produces a current in the thermopile circuit1 which1 reacted on by the field1 produces a deflection4 ,a convex mirror reflecting light is attached so as to move with the thermopile4 ,the instrument is of extraordinary sensitiveness4 ,it responds to 4#e;,e-#f of a degree ,centigrade or about #a;,e-#f degree ,fahrenheit4 ,radiophony4 ,the production of sound by intermittent action of a beam of light upon a body4 ,with possibly a few exceptions all matter may produce sound by radiophouy4 ,range ,finder4 ,an apparatus for use on shipboard to determine the distance of another ship or object4 ,it is designed for ships of war1 to give the range of fire1 so as to set the guns at the proper elevation4 ,the general principle involved is the use of the length of the ship if possible1 if not of its width1 as a base line4 ,two telescopes are trained upon the object and kept trained continuously thereon4 ,the following describes the ,fiske range finder4 ,the range finder comprises two fairly powerful telescopes1 each mounted on a standard1 which can be rotated round a vertical axis1 corresponding with the center of the large disc shown in the engraving4 ,one-half of the edge of this disc is graduated to #ijj on either side of a zero point1 and below the graduation is fixed a length of platinum silver wire4 ,this wire only extends to a distance of #ha4aj on either side of zero1 and is intended to form two arms of a ,wheatstone bridge4 ,the sliding contact is carried by the same arm as the telescope standards1 so that it moves with the telescope4 ,the two instruments are mounted at a known distance apart on the ship1 as shown diagrammatically in the cut4 ,here ,a and ,b are the centers of the two discs1 ,c and ,d the arms carrying the telescopes1 and ,e and ,f the platinum silver wires4 ,suppose the object is at ,t1 such that ,a ,b ,t is a right angle1 then ,,at,,ab_/sin7,,atb74 #ddh ,,standard ,,electrical ,,dictionary4 ,if the two sectors are coupled up as shown1 with a battery1 h1 and a galvanometer1 by the wires1 a b and c d1 then since the arm1 e1 on being aligned on the object takes the position c#a while d remains at zero1 the ,wheatstone bridge formed by these segments and their connections will be out of balance1 and a current will flow through the galvanometer1 which may be so graduated as to give the range by direct reading1 since the current through it will increase with the angle ,a ,t ,b4 ,fig4 #bha4 ,,range ,,finder4 ,in general1 however1 the angle ,a ,b ,t will not be a right angle1 but some other angle4 ,in this case ,,at ,,ab _/ sin7,a ,t ,b7 99 sin7 ,a ,b ,t71 and hence it will only be necessary to multiply the range reading on the galvanometer by the sine of the angle ,a ,b ,t1 which can be read directly by the observer at ,b4 ,this multiplication is not difficult1 but by suitably arranging his electrical appliances ,lieutenant ,fiske has succeeded in getting rid of it1 so that the reading of the galvanometer always gives the range by direct reading1 no matter what the angle at ,b may be4 ,to explain this1 consider the two telescopes shown in the cut in the positions ,c and ,d2 the whole current then has a certain resistance4 #ddi ,,standard ,,electrical ,,dictionary4 ,next suppose them1 still remaining parallel1 in the positions ,c#a and ,d#a4 ,the total resistance of the circuit is now less than before1 and hence if ,c#a1 one of the telescopes1 is moved out of parallel to the other1 through a certain angle1 the current through the galvanometer will be greater than if it were moved through an equal angle out of a parallel when the telescopes were in the positions ,c and ,d4 ,the range indicated is1 therefore1 decreased1 and by properly proportioning the various parts it is found that the range can always be read direct from the galvanometer1 or in other words the multiplication of ,a ,b_/sin7 ,a ,t ,b 7 by sin7 ,a ,b ,t 7 is to all intents and purposes performed automatically4 ,there is1 it is true1 a slight theoretical error2 but by using a small storage battery and making the contents carefully it is said to be inappreciable4 ,each telescope is fitted with a telephone receiver and transmitter1 so that both observers can without difficulty decide on what point to align their telescopes4 ,it will be seen that it is necessary that the lines of sight of two telescopes should be parallel when the galvanometer indicates no current4 ,it has been proposed to accomplish this by sighting both telescopes on a star near the horizon1 which being practically an infinite distance away insures the parallelism of the lines of sight4 ,rate ,governor4 ,an apparatus for securing a fixed rate of vibration of a vibrating reed4 ,it is applied in simultaneous telegraphy and telephoning over one wire4 ,the principle is that of the regular make and break mechanism1 with the feature that the contact is maintained during exactly one-half of the swing of the reed4 ,the contact exists during the farthest half of the swing of the reed away from the attracting pole4 ,fig4 #bhb4 ,,langdon ,,davirs' ,,rate ,,governor4 ,in the left hand figure of the cut1 ,k is the key for closing the circuit4 ,a is the base for attachment of the reed4 ,v is the contact-spring limited in its play to the right by the screw ,s4 ,c is the actuating magnet4 ,by tracing the movements of the reed1 shown on an exaggerated scale in the three right hand figures1 it will be seen that the reed is in electric contact with the spring during about one-half its movement4 ,the time of this connection is adjustable by the screw ,s4 ,synonym--,langdon ,davies' ,rate ,governor or ,phonophone4 #dej ,,standard ,,electrical ,,dictionary4 ,ray1 ,electric4 ,raia torpedo4 ,the torpedo1 a fish having the same power of giving electric shocks as that possessed by the electric eel1 q4 v4 7,see also ,animal ,electricity47 ,fig4 #bhc4 ,,torpedo ,,or ,,electric ,,ray ,reaction of ,dynamo1 ,field and ,armature4 ,a principle of the dynamo current generator1 discovered by ,soren ,hjorth of ,denmark4 ,when the armature is first rotated it moves in a field due to the residual magnetism of the field magnet core4 ,this field is very weak1 and a slight current only is produced4 ,this passing in part or in whole through the field magnet cores slightly strengthens the field1 whose increased strength reacts on the armature increasing its current1 which again strengthens the field4 ,in this way the current very soon reaches its full strength as due to its speed of rotation4 ,the operation is sometimes termed building up4 ,sometimes1 when there is but a trace of residual magnetism1 it is very hard to start a dynamo4 ,reading ,telescope4 ,a telescope for reading the deflections of a reflecting galvanometer4 ,a long horizontal scale is mounted at a distance from the galvanometer and directly below or above the centre of the scale a telescope is mounted4 ,the telescope is so directed that the mirror of the galvanometer is in its field of view1 and the relative positions of mirror1 scale and telescope are such that the image of the scale in the galvanometer mirror is seen by the observer looking through the telescope4 ,under these conditions it is obvious that the graduation of the scale reflected by the mirror corresponds to the deflection of the galvanometer needle4 ,the scale may be straight or curved1 with the galvanometer in the latter case1 at its centre of curvature4 ,reamur ,scale4 ,a thermometer scale in use in some countries of ,continental ,europe4 ,the temperature of melting ice is #j2 the temperature of condensing steam is #hj2 the degrees are all equal in length4 ,for conversion to centigrade degrees multiply degrees ,reamur by #e_/d4 ,for conversion to ,fahrenheit degrees multiply by #i_/d and add #cb if above #j ,r41 and if below subtract #cb4 ,its symbol is ,r41 as #aj ,r4 #dea ,,standard ,,electrical ,,dictionary4 ,recalescence4 ,a phenomenon occurring during the cooling of a mass of steel1 when it suddenly emits heat and grows more luminous for an instant4 ,it is a phase of latent heat1 and marks apparently the transition from a non-magnetizable to a magnetiz able condition4 ,receiver4 ,in telephony and telegraphy1 an instrument for receiving a message as distinguished from one used for sending or transmitting one4 ,thus the ,bell telephone applied to the ear is a receiver1 while the microphone which is spoken into or against is the transmitter4 ,receiver1 ,harmonic4 ,a receiver including an electro-magnet whose armature is an elastic steel reed1 vibrating to a particular note4 ,such a reed responds to a series of impulses succeeding each other with the exact frequency of its own natural vibrations1 and does not respond to any other rapid series of impulses4 7,see ,telegraph ,harmonic47 ,reciprocal4 ,the reciprocal of a number is the quotient obtained by dividing one by the number4 ,thus the reciprocal of #h is #a_/h4 ,applied to fractions the above operation is carried out by simply inverting the fraction4 ,thus the reciprocal of #c_/d is #d_/c or #a-a_/c4 ,record1 ,telephone4 ,attempts have been made to produce a record from the vibrations of a telephone disc1 which could be interpreted by phonograph or otherwise4 ,fig4 #bhd4 ,,morse ,,recorder ,,or ,,embosser4 #deb ,,standard ,,electrical ,,dictionary4 ,recorder1 ,morse4 ,a telegraphic receiving apparatus for recording on a strip of paper the dots and lines forming ,morse characters as received over a telegraph line4 ,its general features are as follows3 ,a riband or strip of paper is drawn over a roller which is slightly indented around its centre4 ,a stylus or blunt point carried by a vibrating arm nearly touches the paper4 ,the arm normally is motionless and makes no mark on the paper4 ,an armature is carried by the arm and an electro-magnet faces the armature4 ,when a current is passed through the magnet the armature is attracted and the stylus is forced against the paper1 depressing it into the groove1 thus producing a mark4 ,when the current ceases the stylus is drawn back by a spring4 ,fig4 #bhe4 ,,inking ,,roller ,,mechanism ,,of ,,morse ,,recorder4 ,in some instruments a small inking roller takes the place of the stylus1 and the roller is smooth4 ,the cut1 ,fig4 #bhe1 shows the plan view of the ink-roller mechanism4 ,j is the roller1 ,l is the ink well1 ,cl is the arm by which it is raised or lowered by the electro-magnet1 as in the embosser4 ,s ,s is the frame of the instrument1 and ,b the arbor to which the arm carrying the armature is secured1 projecting to the right4 ,a spring is arranged to rub against the edge of the inking roller and remove the ink from it4 ,the paper is fed through the apparatus by clockwork4 ,at the present day sound reading has almost entirely replaced the sight reading of the recorder4 ,recorder1 ,siphon4 ,a recording apparatus in which the inked marks are made on a strip of paper1 the ink being supplied by a siphon terminating in a capillary orifice4 ,in the cut ,n ,s represents the poles of a powerful electro-magnet4 ,a rectangular coil bb of wire is suspended between the coils4 ,a stationary iron core a intensifies the field4 ,the suspension wire f f #a has its tension adjusted at h4 ,this wire acts as conductor for the current4 #dec ,,standard ,,electrical ,,dictionary4 ,the current is sent in one or the other direction or is cut off in practice to produce the desired oscillations of the coil b b4 ,a glass siphon n l works upon a vertical axis l4 ,one end l is immersed in an ink well m4 ,its longer end n touches a riband of paper o o4 ,the thread k attached to one side of the coil pulls the siphon back and forth according to the direction of current going through the electro-magnet cores4 ,a spiral spring adjusted by a hand-screw controls the siphon4 ,in operation the siphon is drawn back and forth producing a zigzag line4 ,the upward marks represent dots1 the downward ones dashes4 ,thus the ,telegraphic ,code can be transmitted on it4 ,to cause the ink to issue properly1 electrification by a static machine has been used1 when the stylus does not actually touch the paper1 but the ink is ejected in a series of dots4 ,fig4 #bhf4 ,,siphon ,,recorder4 ,reducteur for ,ammeter4 ,a resistance arranged as a shunt to diminish the total current passing through an ammeter4 ,it is analogous to a galvanometer shunt4 7,see ,multiplying ,power of ,shunt47 ,reducteur for ,voltmeter4 ,a resistance coil connected in series with a ,voltmeter to diminish the current passing through it4 ,its resistance being known in terms of the resistance of the voltmeter it increases the range of the instrument so that its readings may cover double or more than double their normal range4 ,reduction of ,ores1 ,electric4 ,treatment of ores by the electric furnace 7see ,furnace1 ,electric47 ,the ore mixed with carbon and flux is melted by the combined arc and incandescent effects of the current and the metal separates4 ,in another type the metal is brought into a fusible compound which is electrolyzed while fused in a crucible4 ,finally processes in which a solution of a salt of the metal is obtained1 from which the metal is obtained by electrolysis1 may be included4 ,aluminum is the metal to whose extraction the first described processes are applied4 #ded ,,standard ,,electrical ,,dictionary4 ,refraction1 ,electric ,double4 ,double refraction induced in some materials by the action of either an electrostatic1 magnetic or an electro-magnetic field4 ,the intensity or degree of refracting power is proportional to the square of the strength of field4 ,refreshing ,action4 ,in electro-therapeutics the restoration of strength or of nerve force by the use of voltaic alternatives1 q4 v4 ,region1 ,extra-polar4 ,in electro-therapeutics the area or region of the body remote from the therapeutic electrode4 ,region1 ,polar4 ,in electro-therapeutics the area or region of the body near the therapeutic electrode4 ,register1 ,electric4 ,there are various kinds of electric registers1 for registering the movements of watchmen and other service4 ,contact or press buttons may be distributed through a factory4 ,each one is connected so that when the circuit is closed thereby a mark is produced by the depression of a pencil upon a sheet or disc of paper by electro-magnetic mechanism4 ,the paper is moved by clockwork1 and is graduated into hours4 ,for each push-button a special mark may be made on the paper4 ,the watchman is required to press the button at specified times4 ,this indicates his movements on the paper1 and acts as a time detector to show whether he has been attending to his duty4 ,register1 ,telegraphic4 ,a term often applied to telegraph recorders1 instruments for producing on paper the characters of the ,morse or other alphabet4 ,regulation1 ,constant ,current4 ,the regulation of a dynamo so that it shall give a constant current against any resistance in the outer circuits1 within practical limits4 ,it is carried out in direct current machines generally by independent regulators embodying a controlling coil with plunger or some equivalent electro-magnetic device inserted in the main circuit and necessarily of low resistance4 ,in some regulators the work of moving the regulator is executed mechanically1 but under electrical control2 in others the entire work is done by the current4 ,a typical regulator or governor 7,golden's7 of the first class comprises two driven friction wheels between which is a driving friction wheel1 which can engage with one driven wheel only at once4 ,it is brought into engagement with one or the other by a solenoid and plunger4 #dee ,,standard ,,electrical ,,dictionary4 ,as it touches one wheel it turns it in one direction4 ,this moves a sliding contact in one direction so as to increase a resistance4 ,this corresponds to a motion of the plunger in one direction4 ,as the driving wheel moves in the opposite direction by a reverse action it diminishes the resistance4 ,thus the increase and decrease of resistance correspond to opposite movements of the solenoid plunger1 and consequently to opposite variations in the current4 ,the whole is so adjusted that the variations in resistance maintain a constant amperage4 ,the resistance is in the exciting circuit of the dynamo4 ,in ,brush's regulator1 which is purely mechanical1 a series dynamo is made to give a constant current by introducing across the field magnets a shunt of variable resistance1 whose resistance is changed by an electro-magnet1 whose coils are in circuit with the main current4 ,carbon resistance discs are used which the electro-magnet by its attraction for its armature1 presses with varying intensity4 ,this alters the resistance1 decreasing it as the current increases and the reverse4 ,as the connection is in shunt this action goes to maintain a constant current4 ,regulation1 ,constant ,potential4 ,the regulation of constant potential dynamos is executed on the same lines as that of constant current dynamos4 ,if done by a controlling coil1 it must for constant potential regulation be wound with fine wire and connected as a shunt for some part of the machine4 ,regulation of ,dynamos4 ,the regulation of dynamos so that they shall maintain a constant potential difference in the leads of their circuit for multiple arc systems or shall deliver a constant current in series systems4 ,hence two different systems of regulation are required1 7a7 constant potential regulation--7b7 constant current regulation4 ,the first named is by far the more important1 as it concerns multiple arc lighting1 which is the system universally used for incandescent lighting4 ,s4 ,p4 ,thompson thus summarizes the methods of governing or regulating dynamos4 ,premising that alteration of the magnetic flux is the almost universal way of control1 it can be done in two ways2 first1 by varying the excitation or ampere turns of the field1 and second by varying the reluctance of the magnetic circuit4 ,the excitation or magnetic flux may be varied 7a7 by hand1 with the aid of rheostats and commutators in the exciting circuit2 7b7 automatically1 by governors1 taking the place of the hand2 7c7 by compound windings4 ,the magnetic circuit may have its reluctance caused to vary in several ways2 7d7 by moving the pole pieces nearer to or further from the armature2 7e7 by opening or closing some gap in the magnetic circuit 7field-magnet core72 7f7 by drawing the armature endways from between the pole pieces2 7g7 by shunting some of the magnetic lines away from the armature by a magnetic shunt4 ,the latter magnetic circuit methods d1 e1 f1 and g1 have never met with much success except on small machines or motors4 ,method e is adopted in the ,edison motor1 the yoke being withdrawn or brought nearer the cores of the coils4 7,see ,regulation1 ,constant ,current-,regulation1 constant ,potential47 #def ,,standard ,,electrical ,,dictionary4 ,reguline4 adj4 ,having the characteristics of a piece of metal1 being flexible1 adherent1 continuous1 and coherent4 ,applied to electrolytic deposits4 ,relative4 ,indicating the relation between two or more things without reference to absolute value of any one of them4 ,thus one lamp may be of relatively double resistance compared to another1 but this states nothing of the resistance in ohms of either lamp4 ,relay4 ,a receiving instrument which moves in accordance with impulses of currents received1 and in so moving opens and closes a local circuit1 which circuit may include as powerful a battery as required or desirable1 while the relay may be on the other hand so delicate as to work with a very weak current4 ,fig4 #bhg4 ,,relay4 ,the typical relay includes an electro-magnet and armature4 ,to the latter an arm is attached and the lower end of the arm works in pivots4 ,as the armature is attracted the arm swings towards the magnet4 ,when the current is cut off1 the armature and arm are drawn back by a spring4 ,when the arm swings towards the magnet its upper end touching a contact screw closes the local circuit4 ,when it swings back it comes in contact with a second screw1 with insulated point1 and opens the circuit as it leaves the first named screw4 ,one terminal connects with the arm through the pivots and frame4 ,the other connects with the contact screw through the frame carrying it4 ,synonym--,relay ,magnet4 #deg ,,standard ,,electrical ,,dictionary4 ,relay ,bells4 ,bells connected by relay connection to a main line for acoustic telegraphy4 ,a stroke on one bell indicates a dot and on the other a dash4 ,the system is now nearly extinct4 ,relay1 ,box-sounding4 ,a relay which is surrounded by or mounted on a resonator or wooden box of such proportions and size as to reinforce the sound4 ,this enables a relay to act as a sounder1 its weak sounds being virtually magnified so as to be audible4 ,relay ,connection4 ,a connection used in telegraphy1 including a local battery1 with a short circuit normally open1 but closed by a switch and a sounder or other appliance4 ,the latter is made very sensitive so as to be worked by a feeble current1 and is connected to the main line4 ,a very slight current closes the switch and the local battery comes into operation to work a sounder1 etc4 ,when the current ceases on the main line the switch opens and throws the local battery out of action4 ,the switch is termed a relay1 q4 v4 ,a long main line may thus produce strong effects at distant stations1 the intensity of action depending on the local battery4 ,fig4 #bhh4 ,,relay ,,or ,,local ,,circuit4 ,relay1 ,differential4 ,a relay containing two coils wound differentially1 and of the same number of turns and resistance4 ,if two equal currents pass through the coils they counteract each other and no action takes place4 ,if there is a difference in the currents the relay acts as one coil preponderates4 ,the coils may be wound for uneven currents with different resistance and number of turns4 ,relay1 ,microphone4 ,a relay connection applied to a telephone circuit4 ,it consists of a microphone mounted in front of the diaphragm of a telephone receiver4 ,in circuit with the microphone is a battery and second telephone receiver4 ,the microphone is supposed to intensify the sounds of the first telephone4 #deh ,,standard ,,electrical ,,dictionary4 ,relay1 ,polarized4 ,a relay whose armature is of steel1 and polarized or permanently magnetized1 or in which a permanent magnet is used as the basis for the electro-magnets4 ,in the relay shown in the cut the coils shown are mounted on cores carried on the end of a powerful bent permanent magnet4 ,thus when no current passes their upper poles are both of the same sign1 and the horizontally vibrating tongue is held by the magnetic attraction against one or the other pole piece4 ,if a current is sent through the electro-magnet it gives opposite polarity to the two polar extensions4 ,as the end of the vibrating tongue is of polarity determined by the permanent magnet it is attracted to one pole and repelled from the other4 ,on cessation of current it remains attached by the permanent magnetism4 ,if now a current is sent in the opposite direction the two poles again acquire opposite polarity1 the reverse of the former1 and the tongue flies across to the opposite side4 ,on cessation of current it remains attached as before by the permanent magnetism4 ,in its movements to and fro the relay tongue opens and closes a contact1 so as to work a sounder or other apparatus4 ,the polarized relay is of high sensibility1 and requires little or no change of adjustment4 ,fig4 #bhh4 ,,polarized ,,relay ,reluctance4 ,in a magnetic circuit or portion thereof1 the resistance offered to the flow of lines of force4 ,the magnetic circuit as has already been stated is treated like an electric circuit1 and in it reluctance occupies the place of resistance in the electric circuit4 ,it is the reciprocal of permeance4 ,s4 ,p4 ,thompson expresses the law thus3 ,total number of magnetic lines 7magneto-motive force7 _/ 7magnetic reluctance7 ,synonyms--,magnetic ,reluctance-,magnetic ,resistance4 ,reluctance1 ,unit of4 ,the reluctance of a circuit through which unit magnetizing power 7magneto-motive force7 can produce a unit of induction or one line of force4 ,this value is very high2 the reluctance of ordinary magnetic circuits ranges from #a;,e-#e to #a;,e-#h unit of reluctance4 ,reluctivity4 ,specific reluctance2 the reluctance of a cube of material whose edge measures one centimeter in length4 ,it is a quality bearing the same relation to reluctance that permeability does to permeance4 ,it is defined as the reciprocal of magnetic permeability4 7,kenelly47 ,if plotted as a curve for different values of the magnetizing force it is found to be nearly a straight line1 a linear function of the magnetizing force1 ,h with the equation a b ,h4 ,reluctivity is the property of a substance2 reluctance is the property of a circuit4 #dei ,,standard ,,electrical ,,dictionary4 ,remanence4 ,the residual magnetism left after magnetic induction1 expressed in lines of force per square centimeter4 ,repeater4 ,in telegraphy an instrument for repeating the signals through a second line4 ,it is virtually a relay which is operated by the sender1 and which in turn operates the rest of the main line1 being situated itself at about the middle point of the distance covered4 ,in the simpler forms of repeater two relays are used1 one for transmission in one direction the other for transmission in the other4 ,an attendant switches one or the other in as required4 ,thus a common relay is virtually a repeater for its local circuit4 ,if such a relay is placed half way down a line1 and if the line beyond it is connected as its local1 it becomes a repeater4 ,some forms of repeaters are automatic1 and repeat both ways without the need of an attendant4 ,it is the practice to somewhat prolong the signals sent through a repeater4 ,replenisher1 ,sir ,william ,thomson's4 ,a static accumulating influence machine contained in ,thomson's quadrant electrometer and used to change the quadrants4 ,the cut shows the horizontal section and construction of the apparatus4 ,it contains two gilt brass inductors ,a ,b1 and two eccentric sectors or carriers1 ,c1 ,d1 which are mounted on an ebonite spindle1 which is spun around by the fingers4 ,the springs s s#a connect each with its inductor2 the springs ,s ,s#a connect only each other1 and touch the sectors as they turn around4 ,one of the inductors may be always assumed to be of slightly higher potential than that of the other one4 ,when the carriers are in contact with the springs ,s ,s#a they are each charged by induction with electricity opposite in sign to that of the nearest quadrant4 ,as they leave the springs ,s ,s#a in their rotation1 they next touch the springs s s#a1 but of the recently opposite inductor4 ,they share each a portion of its charge with the inductors building up their charges4 ,the action is repeated over and over again as they rotate4 ,fig4 #bij4 ,,thomson',s ,,replenisher4 #dfj ,,standard ,,electrical ,,dictionary4 ,reservoir1 ,common4 ,a term applied to the earth1 because all electrified bodies discharge into it if connected thereto4 ,fig4 #bhi4 ,,diagram ,,of ,,thomson',s ,,replenisher4 ,residual ,atmosphere4 ,the air left in a receiver after exhaustion by an air pump4 ,the quantity1 where good air pumps are used1 is very minute4 ,residue1 ,electric4 ,the residual charge of a condenser4 7,see ,charge1 ,residual47 ,resin4 7a7 ,the product obtained by non-destructive distillation of the juice of the pitch pine4 ,it is the solid residue left after the turpentine has been evaporated or distilled4 ,it is a mixture of abietic acid ,c#dd ,h#fd ,o#e and pinic acid ,c#bj ,h#cj ,o#b4 ,it is an insulator2 its specific inductive capacity is #b4ee4 7,baltzmann47 ,synonyms--,colophony--,rosin4 7b7 ,the name is also generally applied to similar substances obtained from the sap of other trees2 thus shellac is a resin4 ,the resins are a family of vegetable products2 the solid portions of the sap of certain trees4 ,common resin1 lac1 dragons blood1 are examples4 ,they are all dielectrics and sources of resinous or negative electricity when rubbed with cotton1 flannel1 or silk4 7,see ,electrostatic ,series47 #dfa ,,standard ,,electrical ,,dictionary4 ,resinous ,electricity4 ,negative electricity2 the electricity produced upon the surface of a resinous body by rubbing it2 such a body is shellac or sealing wax2 flannel and other substances may be used as the rubbing material4 7,see ,electrostatic ,series47 ,resistance4 7a7 ,the quality of an electric conductor1 in virtue of which it opposes the passage of an electric current1 causing the disappearance of electro-motive force if a current passes through it1 and converting electric energy into heat energy in the passage of a current through it4 ,if a current passes through a conductor of uniform resistance there is a uniform fall of potential all along its length4 ,if of uneven resistance the fall in potential varies with the resistance4 7,see ,potential1 ,fall of47 ,the fall of potential is thus expressed by ,daniell4 ,in a conductor1 say a wire1 along which a current is steadily and uniformly passing1 there is no internal accumulation of electricity1 no density of internal distribution2 there is1 on the other hand1 an unequally distributed charge of electricity on the surface of the wire1 which results in a potential diminishing within the wire from one end of the wire to the other4 ,resistance varies inversely with the cross section of a cylindrical or prismatic conductor1 in general with the average cross-section of any conductor1 and in the same sense directly with its true or average or virtual length4 ,it varies for different substances1 and for different conditions as of temperature and pressure for the same substance4 ,a rise of temperature in metals increases the resistance1 in some bad conductors a rise of temperature decreases the resistance4 #dfb ,,standard ,,electrical ,,dictionary4 ,approximately1 with the exception of iron and mercury1 the resistance of a metallic conductor varies with the absolute temperature4 ,this is very roughly approximate4 ,except for resistance energy would not be expended in maintaining a current through a circuit4 ,the resistance of a conductor may be supposed to have its seat and cause in the jumps from molecule to molecule1 which the current has to take in going through it4 ,if so a current confined to a molecule would1 if once started1 persist because there would be no resistance in a molecule4 ,hence on this theory the ,amprian currents 7see ,magnetism1 ,ampere's ,theory of7 would require no energy for their maintenance and ,ampre's theory would become a possible truth4 ,when metals melt their resistance suddenly increases4 ,light rays falling on some substances1 notably selenium1 q4 v41 vary the resistance4 ,longitudinal stretching of a conductor decreases it1 it increases with longitudinal compression1 and increases in iron and diminishes in tin and zinc when a transverse stress tends to widen the conductor4 7b7 ,the term resistance is used to express any object or conductor used in circuit to develop resistance4 ,transcriber's note3 ,at room temperatures1 the thermal motion of ions in the conductor's crystal lattice scatters the electrons of the current4 ,imperfections of the lattice contribute slightly4 ,at low temperatures superconductivity 7zero resistance7 can occur because an energy gap between the electrons and the crystal lattice prevents any interaction4 ,at the time of this book1 none of this was known4 ,jumps from molecule to molecule is a good guess4 ,resistance1 ,apparent4 ,impedance2 the virtual resistance of a circuit including the spurious resistance due to counter-electromotive force4 ,it may be made up of true resistance and partly of an inductive reaction1 as it represents the net factor1 the entire obstruction to the passage of a current1 and not merely a superadded resistance or counter-electro-motive force4 ,synonym--,impedance4 ,transcriber's note3 ,impedance can also have a component due to capacitance4 ,resistance1 ,asymmetrical4 ,resistance which varies in amount in different directions through a conductor4 ,it implies a compound or composite conductor such as the human system4 ,the presence of counter-electro-motive force in different parts of a conductor may bring about asymmetrical resistance4 ,resistance1 ,b4 ,a4 ,unit of4 ,the ,british ,association ,ohm4 7,see ,ohm1 ,b4 ,a47 #dfc ,,standard ,,electrical ,,dictionary4 ,resistance ,box4 ,a box filled with resistance coils4 ,the coils are connected in series so that a circuit including any given number has their aggregate resistance added to its own4 ,the terminals of consecutive coils are connected to short blocks of brass which are secured to the top of the box1 lying flatwise upon it1 nearly but not quite in contact with each other4 ,plugs of brass are supplied which can go in between pairs of blocks1 which have a pair of grooves reamed out to receive them4 ,such plugs short circuit the coil below them when in position4 ,the cut shows how such coils are connected and the use of plugs to short circuit them4 ,the diagram shows the top of a ,wheatstone bridge1 q4 v41 resistance box with connections for determining resistances4 ,fig4 #bia4 ,,resistance ,,box4 ,resistance ,box1 ,sliding4 ,a resistance box whose coils are set in a circle4 ,two metal arms with handles are pivoted at the centre of the circle and by moving them around they make and break contacts so as to throw the coils in and out of circuit4 ,the object is to permit an operator to adjust resistance without looking at the box--an essential in duplex telegraphy4 ,resistance1 ,breguet ,unit of4 ,the same in origin as the ,digney ,unit4 7,see ,resistance1 ,digney ,unit of47 ,it is equal to #i4feb ,legal ,ohms4 ,resistance1 ,carbon4 ,a resistance1 a substitute for a resistance coil2 it is made of carbon1 and is of various construction4 ,in the ,brush dynamo regulator a set of four vertical piles of plates of retort carbon1 q4 v41 is used as a resistance1 whose resistance is made to vary by changing the pressure4 ,this pressure automatically increases as the current strength increases1 thus reducing the resistance4 #dfd ,,standard ,,electrical ,,dictionary4 ,resistance ,coil1 ,standard4 ,a standard or resistance issued by the ,electric ,standard ,committee of ,great ,britain4 ,the cut shows the standard ohm4 ,it is formed either of ,german silver1 or of an alloy of silver1 #ff4f per cent4 and platinum1 #cc4d per cent4 ,the wire is insulated and doubled before winding as described before4 7,see ,coil1 ,resistance47 ,the two ends of the wire are soldered1 each one to a heavy copper wire or rod r4 ,the whole coil is enclosed in a brass case1 and is enclosed with paraffine melted in at ,a4 ,a place for a thermometer is provided at t4 ,by immersing the lower part of the case ,b in water of different degrees of heat any desired temperature can be attained4 ,fig4 #bib4 ,,standard ,,ohm ,,coil4 ,resistance1 ,combined4 ,the actual resistance of several parallel conductors starting from the same point and ending at the same point4 ,if the individual resistance be a b c d 44 and the combined resistance be x then we have x #a _/ 77 #a_/;a7 7#a_/;b7 7#a_/;c7 7#a_/;d7 '''7 ,synonym--,joint ,resistance4 ,resistance1 ,critical4 ,in a series wound dynamo the resistance of the outer circuit above which the machine will refuse to excite itself4 ,resistance1 ,dielectric4 ,the mechanical resistance of a dielectric to the tendency to perforation or to the strains due to electrification4 ,this is a phase of mechanical resistance1 and is distinct from the electrical or ohmic resistance of the same substance4 ,resistance1 ,digney ,unit of4 ,the resistance of an iron wire1 #a kilometer long1 #d millimeters diameter1 temperature unknown4 ,it is equal to #i4afc legal ohms4 ,resistance1 ,electrolytic4 ,the resistance of an electrolyte to the passage of a current decomposing it4 ,it is almost entirely due to electrolysis and is added to by counter- electro-motive force1 yet it is not treated specifically as such1 but as an actual resistance4 ,when a current of a circuit of too low voltage to decompose an electrolyte is caused by way of immersed terminals to pass through an electrolyte the resistance appears very high and sometimes almost infinite4 ,if the voltage is increased until the electrolyte is decomposed the resistance suddenly drops1 and what should be termed electrolytic resistance1 far lower than the true resistance1 appears4 #dfe ,,standard ,,electrical ,,dictionary4 ,resistance1 ,english ,absolute or ,foot-,second ,unit of4 ,a unit based on the foot and second4 ,it is equal to 77 foot _/ second 7 99 #a;,e#g7 1 being based on these dimensions4 ,it is equal to #j4cjadj legal ohm4 ,resistance1 ,equivalent4 ,a resistance equivalent to other resistances1 which may include counter-electro-motive force4 ,resistance1 ,essential4 ,the resistance of the generator in an electric circuit2 the same as internal resistance4 ,resistance1 ,external4 ,in an electric circuit the resistance of the circuit outside of the generator1 or battery4 ,synonym--,non-essential ,resistance4 ,fig4 #bic4 ,,resistance ,,frame4 ,resistance ,frame4 ,an open frame filled with resistance coils of iron1 or ,german silver wire4 ,it is used as a resistance for dynamos and the larger or working class of plant4 ,the coils are sometimes connected so that by a switch moving over a row of studs one or more can be thrown into series according to the stud the switch is in contact with4 ,resistance1 ,german ,mile ,unit of4 ,the resistance of #h1bch yards of iron wire #a_/f inch in diameter4 ,it is equal to #ef4ha legal ohms4 #dff ,,standard ,,electrical ,,dictionary4 ,resistance1 ,hittorf's4 ,a high resistance1 often a megohm1 composed of ,hittorf's solution1 q4 v4 ,it is contained in a vertical glass tube near whose upper and lower ends are electrodes of metallic cadmium attached to platinum wires4 ,the cadmium is melted in glass tubes1 the platinum wire is inserted into the melted metal and the tube is broken after all is solid4 ,the resistance should show no polarization current4 ,fig4 #bid4 ,,hittorf',s ,,resistance ,resistance1 ,inductive4 ,a resistance in which self-induction is present2 such as a coil of insulated wire wound around an iron core4 ,resistance1 ,insulation4 ,the resistance of the insulation of an insulated conductor4 ,it is stated in ohms per mile4 ,it is determined by immersing a section of the line in water and measuring the resistance between its conductor and the water4 ,the section must be of known length1 and its ends must both be above the liquid4 ,resistance1 ,internal4 ,the resistance of a battery1 or generator in an electric circuit as distinguished from the resistance of the rest of the circuit1 or the external resistance4 ,synonym--,essential ,resistance4 ,resistance1 ,jacobi's ,unit of4 ,the resistance of a certain copper wire #be feet long and weighing #cde grains4 ,it is equal to #j4fbif legal ohm4 ,resistance1 ,matthiessen's ,meter-gram ,standard4 ,the resistance of a pure hard drawn copper wire of such diameter that one meter of it weighs one gram4 ,it is equal to 4#adcd ,legal ,ohms at #j ,c4 7#cb ,f47 ,resistance1 ,matthiessen's ,unit of4 ,the resistance of a standard mile of pure annealed copper wire #a_/af inch diameter1 at a temperature of #ae4e ,c4 7#fj ,f474 ,it is equal to #ac4dd legal ohms4 #dfg ,,standard ,,electrical ,,dictionary4 ,resistance1 ,meter-millimeter ,unit of4 ,the resistance of a wire of copper one meter long and one square millimeter in section4 ,it is equal to 4#jbjeg ohms at #j ,c4 7#cb ,f47 ,the term may also be applied to the resistance of similar sized wire of other metals4 ,resistance1 ,mil-foot ,unit of4 ,the resistance of a foot of copper wire one-thousandth of an inch in diameter4 ,it is equal to #i4hca ohms at #j ,c4 7#cb ,f47 ,the term may also be applied to the resistance of similar sized wire of other metals4 ,resistance1 ,non-essential4 ,the resistance of the portion of an electric circuit not within the generator2 the same as external resistance4 ,synonym--,external ,resistance4 ,resistance1 ,non-inductive4 ,a resistance with comparatively little or negligible self-induction4 ,resistance of ,human ,body4 ,the resistance of the human body is largely a matter of perfection of the contacts between its surface and the electrodes4 ,it has been asserted that it is affected by disease4 ,from #cej to #h1jjj ohms have been determined as resistances1 but so much depends on the contacts that little value attaches to the results4 ,resistance1 ,ohmic4 ,true resistance measured in ohms as distinguished from counter-electro-motive force1 q4 v4 ,the latter is called often spurious resistance4 ,synonym--,true ,resistance4 ,transcriber's note3 ,true vs4 spurious are interesting terms1 considering that today we define impedance as a combination of real resistance and imaginary capacitive and inductive reactance4 ,resistance1 ,reduced4 ,the resistance of a conductor reduced to ohms1 or to equivalent lengths of a column of mercury1 #a square millimeter in cross area4 ,resistance1 ,siemen's ,unit of4 ,the resistance of a column of mercury #a meter long and #a square millimeter cross-sectional area at #j ,c4 7#cb ,f47 ,it is equal to 4#idca legal ohm4 ,resistance1 ,specific4 ,the relative resistance of a substance4 ,it is expressed as the actual resistance of a cube of the substance which is one centimeter on each edge4 ,for metals it is usually expressed in microhms1 for liquids in ohms4 ,the resistances of a specified length of wire of specified diameter of different substances is often given1 and is really a particular way of stating specific resistances4 ,synonym--,specific ,conduction ,resistance4 ,resistance1 ,spurious4 ,the counter-electro-motive force1 q4 v41 operating to prevent a current being produced of what should be its full strength were the true resistance and actuating electro-motive force only concerned4 ,such counter-electro-motive force may be treated as a spurious resistance and such a value in ohms assigned to it as would correspond to its proper effect4 #dfh ,,standard ,,electrical ,,dictionary4 ,in its effect on opposing a current and in resisting its formation it differs from true resistance4 ,the latter in diminishing current strength absorbs energy and develops heat2 spurious resistance opposes and diminishes a current without absorption of energy or production of heat4 ,transcriber's note3 ,spurious resistance is now called reactance1 consisting of capacitive reactance and inductive reactance4 ,the combination of reactance and 7,ohmic_/true7 resistance is called impedance4 ,the calculation of impedance requires complex algebra1 not just real values used in ,,dc circuit analysis4 ,resistance1 ,steadying4 ,when arc lamps are connected in parallel or multiple arc a small resistance coil is sometimes placed in series with each lamp for steadying purposes4 ,it reduces the percentage of variation of resistance in each lamp1 which may be caused by a change in the position of the carbons4 ,resistance1 ,swiss ,unit of4 ,a unit constructed by the ,administration ,suisse1 based on the same data as the ,breguet and the ,digney ,units4 7,see ,resistance1 ,digney ,unit of7 ,it is equal to #aj4cj legal ohms4 ,resistance1 ,thomson's ,unit of4 ,a unit of resistance based on the foot and second4 ,it is equal to #j4caff legal ohm4 ,resistance1 ,unit4 ,unit resistance is that of a conductor in which unit current is produced by unit electro-motive force4 ,resistance1 ,varley's ,unit of4 ,the resistance of a standard mile of a special copper wire #a_/af inch diameter4 ,it is equal to #be4cc ohms4 ,resistance1 ,weber's ,absolute ,unit4 ,a metric system unit2 7meter _/ second7 99 #a;,e#g ,it is equal to #j4ijhi legal ohm4 ,resonance1 ,electric4 ,a set of phenomena known as the ,hertz experiments are grouped under this title1 which phenomena are incidents of and depend on the propagation of electric waves through wires or current conductors1 as well as through the ether4 ,ordinarily a wire is only a seat of current1 and is in its nature inconsistent with wave propagation through its mass4 ,such waves are virtually confined to the exterior of the wire4 ,the point is that the current-producing force is supposed to enter the wire at all points from without1 the current not being produced by an end-push4 ,hence in rapidly recurring waves which are produced by a rapidly pulsatory or alternating current1 no time is afforded for the current-producing force1 in this case the wave-producing force1 to penetrate into the substance of the wire4 ,in one of his experiments ,dr4 ,hertz surrounded a wire by a glass tube chemically silvered4 ,the coating was so thin as to be translucent4 ,through this metallic layer a current could be induced in the wire in its interior4 ,any mechanical layer of metal took up the induction itself1 and protected the central wire4 ,this gave a clue to the thickness of metal penetrated by the rapid induced waves used by ,dr4 ,hertz4 #dfi ,,standard ,,electrical ,,dictionary4 ,fig4 #bie4 ,,electrical ,,resonance ,,exciter4 ,the method used for the production of rapid oscillations is the following4 ,to the terminals of an induction coil two metal spheres ,,aa#a are connected as shown4 ,this apparatus is termed the exciter2 in its discharge a series of isochronous discharges takes place1 alternating in direction4 ,the period of duration ,t of a single one is given by the formula ,t #b99 ,,pi 99 square,root7 ,,lc 71 in which ,c is the capacity and ,l is the self-induction4 ,the spheres may be #cj centimeters 7#aa4h inches7 in diameter1 connected each to conductors #j4e centimeter 74#b inch7 in diameter and #dj centimeters 7#ae4g inches7 long each4 ,for the length of an undulation the formula gives for this apparatus #d4h meters 7#ae4ge feet7 as the length of a wave1 assuming for them the velocity of propagation equal to that of light4 ,the exciter may have #aj1jjj times the rate of oscillation possessed by the plain induction coil4 ,when this apparatus is worked it produces induced waves in every neighboring conductor4 ,the resonance effects appear in the size of the spark induced4 ,thus a wire bent into a circle with its ends nearly touching will give a spark1 but if made of proper electrostatic capacity1 corresponding with the particular waves employed1 the spark will be very much larger4 ,the ring1 with its spark gap is termed a resonator4 ,it is used as an explorer to trace the waves4 ,waves thus produced are transmitted by stone walls and nonconductors in general4 ,a plate of zinc reflects part and transmits part4 ,the reflected waves can be traced by the resonator1 their angle of reflection being equal to their angle of incidence4 ,they can be received by one parabolic reflector1 reflected to another and brought to a focus4 ,they can be reflected so as to produce interference or loops and nodes1 and the loops and nodes can be traced by the resonator4 ,by a prism of asphalt they are refracted exactly like light4 ,from all this it is concluded that an additional proof is furnished of the identity of light and electro-magnetic waves1 and a very strong experimental proof of ,maxwell's theory of light is furnished4 ,synonym--,hertz's ,experiments4 #dgj ,,standard ,,electrical ,,dictionary4 ,fig4 #bif4 ,,electrical ,,resonator4 ,resonator1 ,electric4 ,a small open electric circuit1 with ends nearly touching4 ,when exposed to electric resonance1 or to a sympathetic electric oscillatory discharge1 a spark passes from across the gap4 ,the production of this spark is altogether a matter of the inductance of the resonator4 ,the simplest form is a circle of copper wire with its ends nearly touching4 ,the length of the gap is adjustable by bending4 ,a screw adjustment may also be provided4 ,another form is shown in the cut1 ,fig4 #bif4 ,here sheets of tinfoil are used to regulate the electrostatic capacity1 while at m is shown the finger piece for regulating the size of the spark gap a4 ,synonym--,spark ,micrometer4 ,resultant4 ,the line indicating the result of the application of two or more forces to a point4 ,its direction and length give the elements of direction and intensity4 7,see ,forces1 ,resolution of ,forces1 ,composition of ,components47 ,resultant ,polarity4 ,the magnetic polarity imparted to a mass of iron acted on by two or more separate inducing forces or currents4 ,it appears in dynamos and motors4 ,the final polarity is the resultant of the inducing effect of the field magnet poles and of the windings4 ,retardation4 ,in telegraphy a retardation of the rate of transmission of signals4 ,it is due to several causes4 7a7 ,the self-induction of the circuit1 especially if it includes many electro-magnets1 produces extra currents 7see ,currents1 ,extra47 ,these are opposed to the main current on closing it and hence retard the action4 ,they are in the same direction on opening it and hence again retard the action4 7b7 ,every line has a certain static capacity4 ,this is affected by the proximity of the lines to the earth4 ,for each signal electricity has to be charged upon the line until the line is charged to its end with a certain proportion of the initial density4 ,this charging takes time and hence introduces retardation4 7c7 ,the cores of the electro-magnets of the relays or sounders are not instantly magnetized and demagnetized4 ,this magnetic lag1 q4 v41 introduces retardation4 #dga ,,standard ,,electrical ,,dictionary4 ,retardation of ,phase4 ,the fractional lagging behind of waves or alternating currents2 by lagging behind a portion of a wave length the corresponding phases1 as of full amplitude1 are kept back or retarded4 ,the phase of current intensity may be retarded with reference to the electro-motive force by the introduction of transformers of high capacity with high resistance on open secondary circuits4 ,transcriber's note3 ,capacitors are used to correct current phase lag4 ,retentivity4 ,coercitive or coercive force2 by virtue of which steel retains its magnetism4 ,it is the more modern name1 coercive force as a term being rejected by many4 ,synonyms--,coercive ,force--,coercitive ,force4 ,retort ,carbon4 ,carbon deposited in coal gas retorts from decomposition of the hydrocarbons4 ,it is a very hard1 pure form1 and is of graphitic modification4 ,owing to its great hardness it is little used for electrical purposes1 the molded carbons being easier to make4 ,the deposition occurs in the regular gas-making process1 and is a disadvantage to the working4 ,return4 ,a line or conductor which is supposed to carry current back to its starting point1 after it has traversed a line4 ,it may be a wire or the grounding of the ends of a line or may make the earth act as a return1 termed ground- or earth-return4 ,the best distinction of a return is to so term the portion of a circuit on which no apparatus is placed4 ,reversibility4 ,the principal in virtue of which a device for producing a given form of energy can absorb the same and do work4 ,the reversibility of the dynamo is its quality in virtue of which it can act as a current generator1 thereby converting mechanical energy into electric energy1 or if a current is passed through it1 it rotates1 doing work1 and thereby converting electric energy into mechanical energy4 ,the knowledge of this principle can be traced back to ,jacobi in #ahej4 ,reversible ,bridge4 ,a form of ,wheatstone's ,bridge adapted for reversal of the positions or interchange of the proportionate arms1 v41 so that the accuracy of the coils can be tested4 ,rheochord4 ,an apparatus by means of which variable quantities of wire are thrown into the circuit2 a rheostat using wire4 7,see ,rheostat1 ,wheatstone's47 ,rheometer4 ,a galvanometer4 7,obsolete47 #dgb ,,standard ,,electrical ,,dictionary4 ,rheomotor4 ,a source of current2 a current generator2 a producer of potential difference4 7,obsolete47 ,rheophore4 ,the portion of an active circuit capable of deflecting a magnetic needle4 ,this properly includes all of the metallic conductor of a circuit4 7,obsolete47 ,rheoscope4 ,a galvanoscope2 an instrument for qualitatively detecting potential difference1 fall or rise4 7,see ,galvanoscope47 ,rheostat4 ,an adjustable resistance2 an apparatus for changing the resistance without opening the circuit4 ,its action may depend on the introduction of variable lengths of mercury column1 of some other liquid1 or of wire into a circuit4 7,see ,rheostat1 ,wheatstone's47 ,rheostat ,arm4 ,the third arm of known resistance in a ,wheatstone bridge4 7,see ,proportionate ,arms47 ,rheostatic ,machine4 ,an apparatus for increasing potential difference4 ,it consists of a number of static condensers4 ,they are charged in multiple arc or in parallel1 and are discharged in series4 ,secondary batteries may be used for the charging2 thus a static effect is produced from a galvanic battery4 ,rheostat1 ,wheatstone's4 ,this apparatus consists of two cylinders1 one1 ,a1 made of brass1 the other1 ,b1 of wood1 with a spiral groove4 ,at its end is a copper ring a4 ,a fine brass wire has one end attached to this ring4 ,its other end is fastened at e1 and it is wound as shown2 n and o are binding screws connected1 one with the cylinder-ring a1 the other with the brass cylinder1 ,a4 ,the current entering at o1 traverses the wire on ,b1 as there the windings are insulated by the grooves1 thence it passes to m and by ,a1 whose metal short circuits all the wire on it1 to the binding-post n4 ,the handle1 d1 is turned one way or the other to regulate the length of the wire through which the current must pass4 ,on each cylinder there is a square head1 one of which is shown at c1 so that the handle can be shifted from one to the other as required2 to ,a if the wire is to be wound on that cylinder1 to ,b if the reverse is desired4 ,fig4 #big4 ,,wheatstone',s ,,rheostat4 #dgc ,,standard ,,electrical ,,dictionary4 ,rheotome4 ,an automatic circuit breaker1 one which rapidly opens and closes a circuit1 as in the case of the primary of an induction coil an interrupter4 7,obsolete47 ,rheotrope4 ,a pole changer1 current reverser1 or commutator1 g41 such as the commutator of an induction coil4 7,obsolete47 ,rhigolene4 ,a petroleum product2 a hydrocarbon of low boiling point4 ,its vapor is used in flashing 7q4 v47 carbon filaments for incandescent lamps4 ,rhumbs4 ,in a mariners' compass1 the thirty-two points1 designated1 north1 north by east1 north north east1 etc4 7,see ,compass ,mariner's-,compass1 ,points of the47 ,rhumkorff ,coil4 ,the induction coil1 q4 v4 ,rigidity1 ,molecular4 ,the tendency of molecules to resist rotation or change of position2 the assumed cause of magnetic coercive force1 or retentivity4 ,ring ,contact4 ,a contact formed by a terminal clip in the shape of a ring1 split or cut at one point so that its ends tend to spring together4 ,the other terminal is a bar which passes into the cut and is tightly pressed by the elastic ring4 ,fig4 #bih4 ,,switch ,,with ,,ring ,,contacts4 #dgd ,,standard ,,electrical ,,dictionary4 ,ring1 ,faraday4 ,a closed ring of iron used as the core of a transformer or induction coil4 ,the term is derived from ,faraday's classic experiment with such an apparatus when he produced a spark by induction in a secondary circuit4 ,roaring4 ,a term applied to the noise sometimes produced in a voltaic arc1 when the electrodes are close together and a heavy current is passing4 ,rocker4 ,in a dynamo the movable piece1 mounted concentrically with the commutator1 and carrying the rocker-arms and brush-holders4 ,by moving it the brushes are adjusted for proper lead4 ,rocker ,arms4 ,the arms projecting from a rocker and each carrying one of the brush-holders4 ,roget's ,spiral4 ,an experimental apparatus for illustrating the mutual attraction of currents going in like direction4 ,a cylindrical helix or spiral of wire is suspended by one end4 ,its lower end just dips into a mercury cup4 ,an active circuit is connected1 one terminal to the upper end1 the other terminal to the mercury cup1 bringing the apparatus in series into the circuit4 ,the current as it passes causes the coil to shorten1 each spiral attracting its neighbors4 ,this breaks the circuit by drawing the lower end out of the mercury cup4 ,the current being cut off the coils cease to attract each other1 and the end dips into the mercury cup again4 ,this closes the circuit1 the coils again attract each other and the same sequence follows and is repeated over and over again4 ,a bright spark is produced at each break of the mercury contact4 ,rotation of ,liquids1 ,electro-dynamic4 ,by passing a current through a liquid1 such as dilute sulphuric acid1 it rotates if exposed to the induction of a current flowing at right angles to it4 ,the condition resolves itself into a liquid traversed by horizontal currents from centre to circumference or vice versa1 rotated by a current passing through a circular conductor below it4 #dge ,,standard ,,electrical ,,dictionary4 ,rotation of ,liquids1 ,electro-magnetic4 ,the rotation produced in a liquid carrying centripetal or centrifugal currents by an electromagnet4 ,it is practically an intensification of electro-dynamic rotation4 7,see ,rotation of ,liquids1 ,electro-dynamic47 ,rubber4 ,in a frictional electric machine the cushion of leather which is pressed against the plate as it rotates4 ,s4 7a7 ,symbol for second4 7b7 ,symbol for space1 or length2 ,l is preferable4 7c7 ,symbol for south-seeking pole of a magnet4 ,saddle ,bracket4 ,a bracket carried on the top of telegraph poles1 carrying an insulator for the upper wire4 ,safety ,device4 7a7 ,a device to prevent overheating of any portion of a circuit by excess of current4 ,it generally consists of a slip of fusible metal which if the current attains too much strength melts and opens the circuit4 ,to ensure its breaking a weight is sometimes suspended from the strip4 ,in one form an insulated ,german silver wire is wrapped around the end of the fusible strip a number of times and its end is connected to it4 ,the other end of the ,german silver wire connects with the main lead1 so that all the current goes through both in series4 ,if the ,german silver wire becomes heated from excess of current the coil wrapped tightly around the end of the fusible strip melts it and opens the circuit4 7b7 ,lightning arresters1 q4 v41 may be cited under this heading4 ,synonyms--,automatic ,cut ,out--,safety ,fuse1 ,plug1 or ,strip4 ,fig4 #bii4 ,,cockburn ,,safety ,,fuse4 ,safety ,fuse4 ,a strip of metal inserted so as to form part of a circuit and of such size that a smaller current than would heat the regular wire of the circuit dangerously1 so as to cause a conflagration for instance1 would melt the fuse and open the circuit4 ,as it sometimes happens that a safety fuse melts without parting a weight is sometimes hung upon it1 so as to break it as it softens4 ,salt4 ,a salt is a chemical compound containing two atoms of two radicals14 which saturate each other4 ,one atom or radical is electro-positive referred to the other1 which is electro-negative4 ,by electrolysis salts are decomposed1 the atoms or radicals separating and uniting to form new molecules4 #dgf ,,standard ,,electrical ,,dictionary4 ,saturated4 adj4 ,a liquid is saturated with a substance when it has dissolved all that it can1 while an excess is present in the liquid4 ,it is possible1 by dissolving some salts in hot water and allowing the solution to cool without access of air1 to obtain a supersaturated solution4 ,on introduction of a crystal of the salt1 or often on mere access of air1 the solution forms crystals and the liquid left is saturated4 ,saw1 ,electric4 ,a platinum coated steel wire mounted and connected to be raised to incandescence for cutting purposes4 ,schweigger's ,multiplier4 ,an old term for the galvanometer as invented by ,schweigger soon after ,oerstedt's discovery4 ,scratch ,brushes4 ,brushes for cleaning the surface of articles to be electroplated to give a good metallic surface suitable for deposition4 ,they have often wire instead of bristles4 #dgg ,,standard ,,electrical ,,dictionary4 ,fig4 #cjj4 ,,wire ,,gauze ,,electric ,,screen4 ,screen1 ,electric4 ,a large plate or a hollow case or cage of conducting material connected with the earth1 and used to protect any body placed within it from electrostatic influences4 ,if within a hollow conducting sphere an electrified body is placed1 the inner surface of the sphere will be charged with electricity of opposite kind to that of the sphere1 and the outer surface with the same kind as that of the sphere4 ,thus the sum of the electricities called into action by induction is zero4 ,the two inner charges are bound to each other4 ,the induced charge on the outer surface of the sphere is all that has any effect on objects in the outer air4 ,if the outer surface is connected to the earth it becomes discharged1 and however highly electrified the body introduced into the sphere and the inner surface of such sphere may be1 they produce no external effects1 as they are bound one to the other4 ,if the sphere is connected to the earth and an unelectrified object is placed within it1 such object will be perfectly shielded from the effects of an outer electrostatic field4 ,perforated tinfoil or wire gauze has just as good a result4 ,a large plate of metal connected to the earth has the same effect4 ,the screen whether plane or hollow simply retains a bound charge due to the field of force1 thereby neutralizing it1 and the electricity of the opposite sign escapes to the earth4 ,thus a true shielding or screening effect is produced4 ,in the cut an experiment is shown in which an electric screen is carried by a ,leyden jar4 ,pith balls are suspended outside and inside of it4 ,by the approach of an electrified body the outer pith balls will diverge1 while no effect is produced upon the inner ones4 ,secondary ,actions4 ,in electrolysis the direct products of the electrical decomposition are not always obtained at the electrodes1 but products due to their reaction on the water and other chemicals may appear4 ,these constitute secondary actions4 ,thus if a solution of copper sulphate is electrolyzed with platinum electrodes1 metallic copper appears at one pole and sulphuric acid and oxygen gas at the other4 ,but the products of electrolysis by the current are copper 7,cu7 and sulphion 7,,so#d74 ,the latter reacting on water sets free oxygen gas and forms sulphuric acid4 ,the latter is a secondary action4 ,secondary ,generator4 7a7 ,an alternating current converter generating a so-called secondary current4 7b7 ,a secondary battery1 q4 v41 may be thus termed4 ,secondary1 ,movable4 ,the term movable secondaries has been applied to rings1 spheres and discs of conducting material1 such as copper1 whose behavior when near the pole of an electro-magnet traversed by an alternating current1 have been studied by ,elihu ,thomson4 ,such masses are subjected to very peculiar movements and mutual reactions4 ,as the phenomena are due to induced currents the above term has been applied to the masses in which the currents are induced4 #dgh ,,standard ,,electrical ,,dictionary4 ,secondary ,plates1 ,colors of4 ,in a secondary battery of the lead plate type1 the color of the plates is a good indication of the condition of the battery4 ,the negative plate should be brown or deep-reddish1 the other should be slate-colored4 ,secondary ,poles4 ,poles sometimes found in magnets existing in positions intermediate between the end or true poles4 ,synonym--,consequent ,poles4 ,seebeck ,effect4 ,the production of a current by heating the junction of two different metals forming part of a circuit1 or the thermo-electric production of current1 is stated as the ,seebeck effect1 having been discovered by that investigator4 ,selenium4 ,a non-metallic element4 ,it is interesting electrically on account of the changes its electric resistance undergoes when it is subjected to light4 ,in one set of experiments it was found that diffused light caused the resistance to fall in the ratio of #aa to #i4 ,full sunlight reduced it to one-half4 ,of the spectrum colors red was most powerful and the ultra red region still more strongly affected its resistance4 ,the effect produced by exposure to light is instantaneous1 but on removal to the dark only slowly disappears4 ,a vessel of hot water was found to have no effect1 showing that short ether waves are essential to the effect4 ,selenium ,cell4 ,a selenium resistance box4 ,vitreous selenium is made by keeping ordinary selenium for some hours at a temperature of about #bbj ,c4 7#dbh ,f47 after fusing4 ,it is placed in an electric circuit as part of the conductor4 ,its resistance can then be determined4 ,it decreases in sunlight to about one-half its resistance in the dark4 ,the selenium cell is used in the ,photophone1 q4 v4 ,otherwise it is little more than a subject of experiment4 ,selenium ,eye4 ,a model eye in which selenium in circuit with a battery and galvanometer takes the place of the retina of the human eye4 ,self-repulsion4 ,when a body is electrified each molecule repels its neighbor and the condition in question is thus designated4 ,an electrified soap-bubble expands in virtue of self-repulsion4 ,semi-conductors4 ,substances which conduct static electricity poorly1 but quite appreciably and beyond the extent of leakage4 ,the following are examples3 ,alcohol and ether1 powdered glass1 flowers of sulphur1 dry wood1 paper1 ice at #j ,c4 7#cb ,f47 #dgi ,,standard ,,electrical ,,dictionary4 ,sensibility4 ,the measure of the effect of a current upon a galvanometer1 or any similar case4 ,sensitiveness1 ,angle of ,maximum4 ,every galvanometer has its angle of maximum sensitiveness1 which is the angle of deflection at which a small increment of current will produce the greatest deflection4 ,for every tangent galvanometer #de is the angle in question4 ,in using a galvanometer for direct reading methods it is an object to have it work at its angle of maximum sensitiveness4 ,separately ,excited ,dynamo4 ,a dynamo-electric machine whose field magnet is excited from an outside source1 which may be another dynamo or a battery4 ,alternating current dynamos are often of this description4 ,separate ,touch4 ,in magnetism a method of inducing magnetism in a steel bar4 ,the opposite poles of two magnets are applied at the center of the bar to be magnetized1 but without touching each other1 and are drawn apart to its ends4 ,they are returned through the air and the process is repeated a number of times and on both sides of the bar if necessary4 ,separation of ,electricities4 ,under the double fluid theory of electricity the action of electrification in accumulating positive electricity in one conductor and negative on the other of the excited surfaces of two conductors4 ,separator4 ,india rubber bands or other forms used in batteries to keep the plates from touching in the cell2 especially applied to secondary batteries1 where the plates are so near together as to require separators to prevent short circuiting4 ,fig4 #cja4 ,,series ,,connection4 ,series4 7a7 ,arranged in succession as opposed to parallel4 ,thus if a set of battery jars are arranged with the zinc of one connected to the carbon of the next one for the entire number1 it is said to be arranged in series4 ,when incandescent lamps are arranged in succession so that the current goes through one after the other they are arranged in series4 ,the opposite of parallel1 q4 v41 or multiple arc1 q4 v42 it may be used as a noun or as an adjective4 7b7 ,see ,electro-,chemical ,series2 7c7 ,thermo-,electric ,series 7d7 ,electrostatic ,series2 7e7 ,electro-motive ,series4 ,synonym--,cascade ,connection 7but little used47 #dhj ,,standard ,,electrical ,,dictionary4 ,series-multiple4 ,arrangement of electric apparatus1 in which the parts are grouped in sets in parallel and these sets are connected in series4 ,it is used as a noun1 as arranged in series-multiple1 or as an adjective1 as a series-multiple circuit or system4 ,fig4 #cjb4 ,,series-,,multiple ,,connection4 ,service ,conductors4 ,in electric distribution the equivalents of service pipes in the distribution of gas2 wires leading from the street mains to the houses1 where current is to be supplied4 ,serving4 ,the wrapping or winding of a cable composed of small size wire1 laid closely and smoothly with a tool called a serving mallet1 or serving block1 or by machinery4 ,it serves to protect the cable from wear4 ,shackle4 ,in telegraph lines a swinging insulator bracket for use where wires make an angle with the pole4 ,a journal box is attached to the pole1 like half of a gate hinge4 ,to this a short iron arm is pivoted so as to be free to swing through a considerable angle4 ,at its end an insulator is carried to which the wire is attached4 ,the shackle swings into line with the wire1 or takes a position for two wires corresponding to the resultant of their directions of pull4 ,fig4 #cjc4 ,,double ,,shackle ,shadow4 ,electric4 ,a term applied to a phenomenon of high vacua4 ,if an electric discharge is maintained in a ,crookes' tube the glass opposite the negative electrode tends to phosphoresce4 ,a plate of aluminum1 used also as the positive electrode1 protects the glass directly behind it so as to produce the effect of a shadow4 ,synonym--,molecular ,shadow4 ,transcriber's note3 ,the effect is due to the shadowing of the electrons streaming past the plate4 #dha ,,standard ,,electrical ,,dictionary4 ,sheath for ,magnet ,coils4 ,in #ahfg ,c4 ,e4 ,varley proposed the use of a copper sheath surrounding a magnet core to diminish self-induction4 ,it has since been used by ,brush and others4 ,sometimes metallic foil is laid between the successive coils of wire4 ,synonym--,mutual ,induction ,protector4 ,sheath for ,transformers4 ,a protective sheath of copper1 interposed between the primary and secondary circuits of an alternating current transformer4 ,it is connected to the earth4 ,if the primary coil loses its insulation before it can leak to the secondary it is grounded4 ,this protects the secondary circuit from the high electro-motive force of the primary circuit4 ,shellac4 ,a resin2 produced as an exudation upon the branches of certain ,asiatic trees1 such as the banyan 7,ficus religiosa74 ,it is due to punctures in the bark of the trees in question1 which punctures are made by the female of the insect coccus ficus or c4 lacca4 ,commercial shellac contains about #ij per cent4 of resinous material1 the rest is made up of wax1 gluten1 coloring matter and other substances4 ,shellac is soluble in alcohol1 and in aqueous solutions of ammonium chloride1 of borax and in strong ammonia solution4 ,long standing is required in the case of the last named solvent4 ,dilute hydrochloric and acetic acids dissolve it readily2 nitric acid slowly2 strong sulphuric acid is without action on it4 ,alkalies dissolve it4 ,in electric work it is used as an insulator and dielectric4 ,its alcoholic solution is used to varnish glass plates of influence machines1 for the coils of induction coils and similar purposes4 ,resistance in ohms per centimeter cube at #bh ,c4 7#hb4d ,f47--7,ayrton71 #i4j;,e#ae ,specific ,inductive ,capacity 7,wllner71 #b4ie to #c4gc ,the same substance in less pure forms occurs in commerce1 as stick lac1 lump lac1 seed lac1 button lac4 ,shellac ,varnish4 ,solution of shellac in alcohol2 methylic alcohol 7wood alcohol or wood naphtha7 is often used as solvent4 ,dr4 ,muirhead recommends button lac1 dissolved in absolute alcohol1 and the top layers decanted4 ,for highest insulation he dissolves the lac in ordinary alcohol1 precipitates by dropping into water1 collects the precipitate1 dries and dissolves in absolute alcohol4 ,shielded4 adj4 ,an electric measuring instrument of the galvanometer type is shielded when it is so constructed that its indications are not seriously affected by the presence of neighboring magnets or by fields of force4 ,shielding can be effected by using a very strong permanent magnet to produce a field within which the magnetic needle moves and which reacts upon it1 or by enclosing the instrument in a thick iron box4 #dhb ,,standard ,,electrical ,,dictionary4 ,s4 ,h4 ,m4 ,symbol or abbreviation for simple harmonic motion4 ,shock1 ,break4 ,a term in electro-therapeutics2 the shock received when an electric circuit1 including the patient in series1 is broken or opened4 ,synonym--,opening ,shock4 ,shock1 ,electric4 ,the effect upon the animal system of the discharge through it of electricity with high potential difference4 ,pain1 nervous shock1 violent muscular contortions accompany it4 ,of currents1 an alternating current is reputed worse than a direct current2 intermediate is the pulsatory current4 ,the voltage is the main element of shock1 amperage has also some direct influence4 ,shock1 ,static4 ,a term in electro-therapeutics4 ,the application of static discharges from small condensers or ,leyden jars to a patient who is insulated from the ground with one electrode applied to the conducting surface on which he rests1 while the other1 a spherical electrode1 is brought near the body so as to produce a disruptive or spark discharge4 ,short ,circuit4 ,a connection between two parts of a circuit1 which connection is of low resistance compared to the intercepted portion4 ,the term is used also as a verb1 as to short circuit a lamp4 ,fig4 #cjd4 ,,diagram ,,illustrating ,,short ,,circuit ,,working4 ,short ,circuit ,working4 ,a method of working intermittently an electro-magnet so as to avoid sparking4 ,it consists in providing a short circuit in parallel with the magnetic coils4 ,this short circuit is of very low resistance4 ,to throw the magnet into action the short circuit is opened2 to throw it out of action the short circuit is closed4 ,the shunt or short circuit must be of negligibly small resistance and inductance4 #dhc ,,standard ,,electrical ,,dictionary4 ,shovel ,electrodes4 ,large plate electrodes used in a medical bipolar bath4 7,see ,bath1 ,bipolar47 ,shunt4 ,in a current circuit a connection in parallel with a portion of the circuit4 ,thus in a dynamo a special winding for the field may have its ends connected to the bushes1 from which the regular external circuit also starts4 ,the field is then wound in shunt with the armature4 ,in the case of a galvanometer a resistance coil may be put in parallel with it to prevent too much current going through the galvanometer2 this connection is a shunt4 ,the word is used as a noun1 as a shunt1 or a connection or apparatus in shunt with another1 and as an adjective1 as a shunt connection1 or as a verb1 as to shunt a battery4 ,shunt ,box4 ,a resistance box designed for use as a galvanometer shunt4 7,see ,shunt1 ,galvanometer47 ,the box contains a series of resistance coils which can be plugged in or out as required4 ,shunt1 ,electro-magnetic4 ,in telegraphy a shunt for the receiving relay consisting of the coils of an electro-magnet4 ,it is placed in parallel with the relay4 ,its poles are permanently connected by an armature4 ,thus it has high self-induction4 ,on opening and closing the circuit by the sending key1 extra currents are produced in the shunt4 ,the connections are so arranged that on making the circuit the extra current goes through the relay in the same direction as the principal current1 while on breaking the circuit the induced current goes in the opposite direction4 ,thus the extra currents accelerate the production and also the cessation of signalling currents1 tending to facilitate the operations of sending despatches4 ,shunt1 ,galvanometer4 ,a resistance placed in parallel with a galvanometer1 so as to short circuit its coils and prevent enough current passing through it to injure it4 ,by knowing the resistance of the shunt and of the galvanometer coils1 the proportion of current affecting the galvanometer is known4 ,this gives the requisite factor for calculation4 7,see ,multiplying ,power of ,shunt47 ,shunt ,ratio4 ,the coefficient expressing the ratio existing between the current in a shunt and in the apparatus or conductor in parallel with it4 7,see ,multiplying ,power of_/ ,shunt47 ,shunt ,winding4 ,a dynamo or motor is shunt-wound when the field magnet winding is in shunt or in parallel with the winding of the armature4 ,shuttle ,current4 ,a current alternating in direction2 an alternating current4 #dhd ,,standard ,,electrical ,,dictionary4 ,side-,flash4 ,a bright flashing lateral discharge from a conductor conveying a current due to a static discharge4 ,sighted ,position4 ,in an absolute electrometer 7see ,electrometer1 ,absolute7 the position of the balanced arm carrying the movable disc or plate1 when the disc and guard plate are in one plane4 ,the cross-hair on the lever-end is then seen midway between two stops1 or some other equivalent position is reached which is discerned by sighting through a magnifying glass or telescope4 ,silver4 ,a metal2 one of the elements2 symbol ,ag42 atomic weight1 #ajh2 valency1 #a2 equivalent1 #ajh2 specific gravity1 #aj4e4 ,it is a conductor of electricity4 ,relative resistance1 annealed1 #a4j ,specific ,resistance1 annealed1 at #j ,c4 7#cb ,f47 #a4ejd microhms4 ,resistance of a wire at #j ,c4 7#cb ,f471 ,annealed4 ,hard ,drawn4 7a7 #a foot long1 weighing #a grain1 4#baij ohms 4#bchi ohms4 7b7 #a foot long1 #a_/ajjj inch thick1 #i4jdh #i4hbf 7c7 #a meter long1 weighing #a gram1 4#aebg 4#affb 7d7 #a meter long1 #a millimeter thick1 4#jaiaf 4#jbjhj ,resistance annealed of a #a-;inch cube1 at #j ,c4 7#cb;,f47 4#eiba microhms4 ,percentage increase in resistance per degree ,c4 7#a4h ,f47 at about #bj ,c4 7#fh ,f471 annealed1 #j4cgg per cent4 ,electro-chemical equivalent1 7,hydrogen 4#jaje7 4#aacd mgs4 ,silver ,bath4 ,a solution of a salt of silver for deposition in the electroplating process4 ,the following is a typical formula3 ,water1 #aj4j parts by weight4 ,potassium ,cyanide1 #e ,metallic ,silver1 #b4e ,the silver is first dissolved as nitrate and converted into cyanide and added in that form1 or for #b4e parts metallic silver we may read3 ,silver cyanide1 #c parts by weight4 ,while many other formulas have been published the above is representative of the majority4 ,other solvents for the silver than potassium cyanide have been suggested1 such as sodium hyposulphite1 but the cyanide solution remains the standard4 ,silver ,stripping ,bath4 ,various baths are used to remove silver from old electroplated articles4 ,their composition depends upon the base on which the metal is deposited4 ,silvered iron articles are placed as anodes in a solution of #a part potassium cyanide in #bj parts of water4 ,as kathode a silver anode or a copper one lightly oiled may be used4 ,from the latter the silver easily rubs off4 ,for copper articles a mixture of fuming sulphuric acid and nitric acid 7#dj ,beaum7 may be used4 ,the presence of any water in this mixture will bring about the solution of the copper4 ,or fuming sulphuric acid may be heated to between #cjj and #djj ,f41 some pinches of dry pulverized potassium nitrate may be thrown in and the articles at once dipped4 ,these methods effect the solution of the silver1 leaving the copper unattacked4 #dhe ,,standard ,,electrical ,,dictionary4 ,simple ,substitution4 ,a method of obtaining a resistance equal to that of a standard4 ,the standard is put in circuit with a galvanometer and the deflection is noted4 ,for the standard another wire is substituted and its length altered until the same deflection is produced4 ,the two resistances are then evidently identical4 ,the standard can be again substituted to confirm the result4 ,sine ,curve4 ,if we imagine a point moved back and forth synchronously with a pendulum1 and if such point made a mark upon paper1 it would trace the same line over and over again4 ,if now the paper were drawn steadily along at right angles to the line of motion of the point1 then the point would trace upon it a line like the profile of a wave4 ,such line is a sine curve4 ,it derives its name from the following construction4 ,let a straight line be drawn1 and laid off in fractions1 such as degrees1 of the perimeter of a circle of given diameter4 ,then on each division of the line let a perpendicular be erected equal in height to the sine of the angle of the circle corresponding to that division2 then if the extremities of such lines be united by a curve such curve will be a sine curve4 ,in such a curve the abscissas are proportional to the times1 while the ordinates are proportional to the sines of angles1 which angles are themselves proportional to the times4 ,the ordinates pass through positive and negative values alternately1 while the abscissas are always positive4 ,any number of sine curves can be constructed by varying the diameter of the original circle1 or by giving to the abscissas a value which is a multiple of the true length of the divisions of circle4 ,if the pendulum method of construction were used this would be attained by giving a greater or less velocity to the paper as drawn under the pendulum4 ,a species of equation for the curve is given as follows3 y sin7 x 7 ,in this x really indicates the arc whose length is x1 and reference should be made to the value of the radius of the circle from which the curve is described4 ,it will also be noticed that the equation only covers the case in which the true divisions of the circle are laid off on the line4 ,if a multiple of such divisions are used1 say n times1 or #a-n times1 then the equation should read y n sin7 x 7 or y sin7 x 7 _/ n ,synonyms--,curve of ,sines--,sinusoidal ,curve--,harmonic ,curve4 #dhf ,,standard ,,electrical ,,dictionary4 ,sine ,law4 ,the force acting on a body is directly proportional to the sine of the angle of deflection when-- ,i4 ,the controlling force is constant in magnitude and direction2 and ,,ii4 ,the deflecting force1 although variable in its direction in space1 is fixed in direction relatively to the deflecting body4 ,single ,fluid ,theory4 ,a theory of electricity4 ,electricity1 as has been said1 being conveniently treated as a fluid or fluids1 the single fluid theory attributes electrical phenomena to the presence or absence of a single fluid4 ,the fluid repels itself but attracts matter2 an excess creates positive1 a deficiency1 negative electrification2 friction1 contact action or other generating cause altering the distribution creates potential difference or electrification4 ,the assumed direction 7see ,direction7 of the current and of lines of force are based on the single fluid theory4 ,like the double fluid theory1 q4 v41 it is merely a convenience and not the expression of a truth4 7,see ,fluid1 ,electric1 and ,double ,fluid ,theory47 ,synonym--,franklin's ,theory4 ,single ,fluid ,voltaic ,cell4 ,a galvanic couple using only a single fluid1 such as the ,smee or ,volta cell4 ,simple ,harmonic ,motion4 ,motion of a point or body back and forth along a line2 the motion of a pendulum1 as regards its successive swings back and forth1 is an example of harmonic motion4 ,sinistrotorsal4 adj4 ,the reverse of dextrotorsal1 q4 v4 ,a helix with left-handed winding1 the reverse of an ordinary screw1 such as a wood-screw or corkscrew4 ,skin ,effect4 ,a current of very brief duration does not penetrate the mass of a conductor4 ,alternating currents for this reason are mainly conducted by the outer layers of a conductor4 ,the above is sometimes called the skin effect4 ,sled4 ,a contact for electric cars of the conduit system4 ,it is identical with the plow1 q4v41 but is drawn after the cars instead of being pushed along with them4 ,slide ,meter ,bridge4 ,a name for a ,slide ,bridge one meter long4 ,there are also slide half meter and slide quarter meter bridges and others4 7,see ,meter ,bridge47 ,s4 ,n4 ,code4 ,abbreviation for single needle code1 the telegraphic alphabet used with the single needle system4 ,soaking-in-and-out4 ,a term for the phenomena of the residual electrostatic charge2 the gradual acquirement or loss by a condenser of a portion of its electrostatic charge4 #dhg ,,standard ,,electrical ,,dictionary4 ,soldering1 ,electric4 7a7 ,soldering in which the solder is melted by means of electricity2 either current incandescence or the voltaic arc may be used4 ,it is identical in general with electric welding4 7,see ,welding1 ,electric47 7b7 ,the deposition by electric plating of a metal over the ends of two conductors held in contact4 ,this secures them as if by soldering4 ,it is used in connecting the carbon filament of an incandescent lamp with the platinum wires that pass through the glass4 ,copper is the metal usually deposited4 ,solenoid4 ,the ideal solenoid is a system of circular currents of uniform direction1 equal1 parallel1 of equal diameter of circle1 and with their centers lying on the same straight line1 which line is perpendicular to their planes4 ,fig4 #cje4 ,,experimental ,,solenoid4 ,the simple solenoid as constructed of wire1 is a helical coil1 of uniform diameter1 so as to represent a cylinder4 ,after completing the coil one end of the wire is bent back and carried through the centre of the coil1 bringing thus both ends out at the same end4 ,the object of doing this is to cause this straight return member to neutralize the longitudinal component of the helical turns4 ,this it does approximately so as to cause the solenoid for its practical action to correspond with the ideal solenoid4 ,instead of carrying one end of the wire through the centre of the coil as just described1 both ends may be bent back and brought together at the centre4 ,a solenoid should always have this neutralization of the longitudinal component of the helices provided for2 otherwise it is not a true solenoid4 ,solenoids are used in experiments to represent magnets and to study and illustrate their laws4 ,when a current goes through them they acquire polarity1 attract iron1 develop lines of force and act in general like magnets4 ,a solenoid is also defined as a coil of insulated wire whose length is not small as compared with its diameter4 #dhh ,,standard ,,electrical ,,dictionary4 ,sonometer1 ,hughes'4 ,a sound measurer2 a modification of a portion of ,hughes' induction balance1 used for testing the delicacy of the ear or for determining the relative intensity of sounds4 7,see ,hughes' ,induction ,balance47 ,it is the arrangement of three coils1 two mounted one at each of the ends of a graduated bar1 and the third one between them and free to slide back and forth thereon4 ,sonorescence4 ,the property of producing sounds under the influence of momentary light radiations rapidly succeeding each other4 ,it is the property utilized in the photophone1 q4 v4 ,fig4 #cjf4 ,,morse ,,sounder4 ,sounder4 ,in telegraphy an instrument consisting of an electromagnet with armature attached to an oscillating bar1 the range of whose movements is restricted by adjusting screws4 ,the armature is drawn away from the magnet by a spring4 ,when a current is sent through the magnet the armature is drawn towards the poles and produces a sound as the bar strikes a striking piece or second adjusting screw4 ,when the current ceases the bar and armature are drawn back1 striking the first mentioned screw with a distinct sound1 the back stroke4 ,the sounder is used to receive ,morse and analogous character messages4 ,the forward strokes correspond to the beginnings of the dots or dashes of the code1 the back strokes to beginnings of the intervals4 ,the distinction between dots and dashes is made by observing the interval between forward and back stroke4 ,various devices are used to increase the sound4 ,sometimes a resonance box is used on which the sounder is mounted4 ,in practice sounders are generally placed on local circuits and are actuated by relays4 #dhi ,,standard ,,electrical ,,dictionary4 ,sound ,reading4 ,the art or method of receiving telegraph messages by ear4 ,it is now universally used by all expert ,morse operators4 ,it can only be applied to telegraph systems producing audible sounds2 in some cases1 as in needle telegraphy1 it may be quite inapplicable4 ,space1 ,clearance4 ,the space between faces of the pole pieces and the surface of the armature in a dynamo4 ,it is really the air gap1 but in calculating dynamo dimensions the thickness of the insulated copper wire windings of the commutator are counted in as part of the air gap1 because copper is almost the same as air in impermeability4 ,clearance space is a mechanical factor2 the air gap is an electric or magnetic factor4 ,synonym--,inter-air ,space4 ,space1 ,crookes' ,dark4 ,in an exhausted tube1 through which an electric discharge is caused to pass1 the space surrounding the negative electrode of the tube4 ,this space is free from any luminous effect1 and by contrast with the light of the discharge appears dark4 ,the vacuum may be made so high that the dark space fills the whole space between the electrodes4 ,it is less for a less vacuum and varies for other factors1 such as the temperature of the negative electrode from which it originates1 the kind of residual gas present1 and the quality of the spark4 ,space1 ,faraday's ,dark4 ,the space in an exhausted tube between the luminous glows about the two electrodes4 ,space1 ,interferric4 ,a term for the air-gap in a magnetic circuit4 ,it is etymologically more correct than air-gap1 for the latter is often two-thirds or more filled with the insulating material and copper wire of the armature windings4 7,see ,space1 ,clearance47 ,spark ,arrester4 ,a screen of wire netting fitting around the carbons of an arc lamp above the globe to prevent the escape of sparks from the carbons4 ,spark ,coil4 ,a coil for producing a spark from a source of comparatively low electro-motive force4 ,it consists of insulated wire wound round a core of soft iron1 best a bundle of short pieces of wire4 ,such a coil may be eight inches long and three inches thick1 and made of ,no4 #ah-bj copper wire1 with a core one inch in diameter4 ,on connecting a battery therewith and opening or closing the circuit1 a spark is produced by self-induction1 q4 v4 ,it is used for lighting gas4 #dij ,,standard ,,electrical ,,dictionary4 ,spark1 ,duration of ,electric4 ,wheatstone determined the duration of the spark given by a ,leyden jar as #a_/bdjjj second4 ,feddersen by interposing a tube of water #i millimeters 74#cf inch7 long in its path found that it lasted #ad_/ajjjj second1 and with one #ahj millimeters 7#g4b inches7 long1 #ahh_/ajjjj second4 ,lucas and ,cazin for a #e millimeter 74#b inch7 spark1 with different numbers of ,leyden jars1 found the following3 ,number of jars4 ,duration of ,spark4 #b 4#jjjjbf second #d 4#jjjjda #f 4#jjjjde #h 4#jjjjdg ,the duration increases with the striking distance1 and is independent of the diameter of the balls between which it is produced4 ,spark ,gap4 ,the space left between the ends of an electric resonator 7see ,resonator1 ,electric7 across which the spark springs4 ,its size may be adjustable by a screw1 something like the arrangement of screw calipers4 ,sparking4 ,in dynamo-electric machines1 the production of sparks at the commutator between the brushes and commutator sections4 ,the sparks are often true voltaic arcs1 and in all cases are injurious if in any quantity1 wearing out the commutator and brushes4 ,sparking1 ,line or ,points of ,least4 ,in a dynamo or electric motor the diameter of the commutator determining1 or the points on the commutator marking the position of the brushes where the sparking is a minimum4 ,field magnets powerful in proportion to the armature are a preventative cause4 ,the direction of the line fixes the angle of lead to be given to the brushes4 ,sparking1 ,resistance to4 ,the resistance to disruptive discharge through its substance offered by a dielectric or insulator4 ,it does not depend on its insulating qualities1 but on its rigidity and strength4 ,spark1 ,length of4 ,the length of the spark accompanying the disruptive discharge is counted as the distance from one electrode to the other in a straight line4 ,it is longer for an increased potential difference between the two electrodes4 ,if the gas or air between the electrodes is exhausted the length increases1 until the vacuum becomes too high1 when the length begins to decrease1 and for a perfect vacuum no spark however small can be produced4 ,the shape of the conductor which is discharged1 the material of the electrodes1 and the direction of the current are all factors affecting the length of spark producible4 #dia ,,standard ,,electrical ,,dictionary4 ,spark ,tube4 ,a tube used as a gauge or test to determine when the exhaustion of the vacuum chamber or bulb of an incandescent lamp is sufficiently high4 ,the interior of the tube is connected with the interior of the bulb or chamber of the lamps in process of exhaustion1 and hence shares their degree of exhaustion4 ,from time to time connections with an induction coil are made4 ,when the exhaustion is carried far enough no discharge will take place through the vacuum4 ,as long as the tube acts like a ,geissler tube the exhaustion is not considered perfect4 ,specific ,heat of ,electricity4 ,the heat absorbed or given out by a fluid in passing from one temperature to another depends on its specific heat4 ,in the ,peltier and the ,thomson effects4 q4 v41 the electric current acts as the producer of a change of temperature1 either an increase or decrease as the case may be4 ,this suggests an absorption of and giving out of heat which amount of heat corresponding to a current of known amount is determinable1 and may be referred to any unit of quantity such as the coulomb4 ,this or some equivalent definite quantity of heat it has been proposed 7,sir ,william ,thomson7 to term the ,specific ,heat of ,electricity4 ,spent ,acid4 ,acid which has become exhausted4 ,in a battery the acid becomes spent from combination with zinc4 ,it also loses its depolarizing power1 if it is a chromic acid solution or of that type1 and then may be said to be spent4 ,spent ,liquor4 ,the liquor of a plating bath which has become exhausted from use1 the metal it contained being all or partly deposited4 ,sphygmograph1 ,electric4 ,an electric apparatus for recording the beat of the pulse1 both as regards its rate and strength4 ,sphygmophone4 ,an apparatus for examination of the pulse by the microphone and telephone4 ,spiders4 ,core-discs of a dynamo or motor armature are sometimes perforated with a large central aperture1 are fastened together with insulated bolts1 and the whole mass is secured to the shaft by three- or four-armed spiders4 ,these are like rimless wheels1 the ends of their arms being secured to the hollow cylinder constituting the armature core1 and a central aperture in their hub receiving the shaft4 #dib ,,standard ,,electrical ,,dictionary4 ,spiral4 ,this term is sometimes used instead of coil1 as the primary spiral or secondary spiral of an induction coil or transformer4 ,spiral ,winding4 ,the winding used on ring armatures4 ,this may diagrammatically be represented by a spiral carried around the ring shaped core4 ,with two field poles it gives two collecting points1 positive and negative1 with four field poles it gives four collecting points1 alternately positive and negative4 ,splice ,box4 ,a box in which the splices in underground cables and electric lines are contained4 ,the splicing is generally done in the boxes with the cables in place4 ,they may be two-way for straight lines1 or be four-way for two side or lateral connections4 ,spluttering4 ,a term applied to a sound sometimes produced in a voltaic arc1 perhaps caused by impure or insufficiently baked electrodes4 7,elihu ,thomson47 ,spring ,control4 ,control of or giving the restitutive force to the needle of a galvanometer1 core of a solenoid ammeter or moving part of any similar instrument by a spring4 ,as an example see ,ammeter1 ,ayrton's4 ,fig4 #cjg4 ,,spring ,,jacks4 ,spring ,jack4 ,an arrangement for effecting1 at one insertion of a species of plug1 the opening or breaking of a circuit and for the simultaneous connection to the terminals formed by the breaking of two terminals of another system or loop4 ,thus let a line include in its circuit two springs pressing against each other1 thereby completing the circuit4 ,if a plug or wedge of insulating material were inserted between the springs so as to press them apart it would break the circuit and the whole would constitute a spring jack cut-out4 ,if each side of the plug had a strip of brass or copper attached to it1 and if the ends of another circuit were connected to these strips1 then the insertion of the plug would throw the new line into the circuit of the other line4 #dic ,,standard ,,electrical ,,dictionary4 ,spring ,jack ,cut-out4 ,a cut-out1 of the general construction of a spring jack1 q4 v41 except that a simple insulating plug or wedge is used in place of the metal-faced wedge with its connections of the regular spring jack4 ,the insertion of an insulating wedge opens the circuit1 which on its removal is closed4 ,the regular spring jack wedge will operate in the same way1 if its connections are kept open4 ,spurious ,voltage4 ,the voltage in excess of that developed by a secondary battery which is required in the charging process4 ,it is about 4#be volt4 ,square ,wire4 ,wire whose cross-section is a square4 ,it has been used of iron for building up the cores of armatures for dynamos or motors1 for which it is peculiarly suitable1 and also of copper as a winding for armatures4 ,staggering4 adj4 ,when the brushes of a dynamo are set1 one a little in advance of the other on the surface of the commutator1 they are said to be set staggering4 ,it is used to get over a break in the armature circuit4 ,state1 ,electrotonic4 ,a term expressing an abandoned theory4 ,faraday at one time proposed the theory that a wire had to be in the electrotonic state to produce electro-motive force by movement through an electric field4 ,any such idea was ultimately abandoned by ,faraday4 ,static ,breeze4 ,the electric breeze obtained by the silent discharge of high tension electricity4 ,static ,electricity4 ,electricity at rest or not in the current form ordinarily speaking4 ,the term is not very definite and at any rate only expresses a difference in degree1 not in kind4 ,the recognition of the difference in degree has now to a great extent also disappeared4 ,station1 ,central4 ,the building or place in which are placed electrical apparatus1 steam engines and plant supplying a district with electric energy4 ,station1 ,distant4 ,the place at the further end of a telegraph line1 as referred to the home station4 ,station1 ,home4 ,the end of a telegraph line where the operators using the expression are working4 #did ,,standard ,,electrical ,,dictionary4 ,station1 ,transforming4 ,in alternating current distribution1 a building or place where a number of transformers are worked1 so that low potential or secondary circuits are distributed therefrom4 ,steel4 ,a compound of iron with carbon4 ,the carbon may range from a few hundredths of one per cent4 up to two per cent4 ,for magnets1 tool steel drawn to a straw color or a little lower is good4 ,all shaping and filing should be done before magnetization4 ,steeling4 ,the deposition of iron on copper plates by electrolysis4 ,in electrotyping a thin deposit of iron is thus given the relief plates before printing from them4 ,the deposit is very hard and exceedingly thin1 so that it does not interfere with the perfection of the impression in the printing process4 ,as the iron becomes worn it can be dissolved off with hydrochloric acid1 which does not dissolve the copper1 and a new deposit can be given it4 ,thus the plate may last for an indefinite number of impressions4 ,the iron bath may be prepared by immersing in a solution of ammonium chloride1 two plates of iron1 connected as anode and kathode in a circuit4 ,one plate dissolves while hydrogen is given off from the other4 ,the solution thus produced is used for a bath4 ,the hardness of the deposit1 which is really pure iron1 gives the name of steeling4 ,synonym--,acierage4 ,st4 ,elmo's ,fire4 ,luminous static discharge effects sometimes seen on objects elevated in the air4 ,they are especially noticed on ships' masts4 ,the sailors term them corpusants 7holy bodies74 ,they resemble tongues or globes of fire4 ,step-by-step ,telegraphy4 ,a system of telegraphy in which in the receiving instrument a hand is made to move step-by-step1 with an escape movement around a dial4 ,for each step there is a letter and the hand is made to stop at one or the other letter until the message is spelled out4 7,see ,dial ,telegraph47 ,step-down4 adj4 ,a qualification applied to a converter or transformer in the alternating current distribution1 indicating that it lowers potential difference and increases current from the secondary4 ,step-up4 adj4 ,the reverse of step-down2 a qualification of a transformer or converter indicating that it raises the potential and decreases the current in the secondary4 ,sticking4 ,the adherence1 after the current is cut off1 of the armature to the poles of a magnet4 ,in telegraphy it is a cause of annoyance and obstructs the working4 ,it may1 in telegraphy1 be due to too weak a spring for drawing back the armature1 or to imperfect breaking of the contact by the despatcher's key or by the receiver's relay4 #die ,,standard ,,electrical ,,dictionary4 ,stopping ,off4 ,in electroplating the prevention of deposition of the plating metal on any desired portions of the object4 ,it is effected by varnishing the places where no coating is desired4 ,an article can be plated with silver1 stopped off in any desired design1 and the unvarnished portions may then be plated with gold in another bath4 ,various effects can be produced by such means4 ,storage ,capacity4 ,a term for the ampere-hours of electricity1 which can be taken in current form from a storage battery4 ,storage of ,electricity4 ,properly speaking electricity can only be stored statically or in static condensers1 such as ,leyden jars4 ,the term has been popularly applied to the charging of secondary or storage batteries1 in which there is really no such thing as a storage of electricity1 but only a decomposition and opposite combination brought about1 which leave the battery in a condition to give a current4 ,storms1 ,electric4 ,wide-spread magnetic and electric disturbances1 involving the disturbance of the magnetic elements and other similar phenomena4 7,see ,magnetic ,storms47 ,strain4 ,the condition of a body when subjected to a stress4 ,various consequences may ensue from strain in the way of disturbance of electric and other qualities of the body strained4 ,stratification ,tube4 ,a ,geissler tube1 q4 v41 for showing the stratification of the electric discharge through a high vacuum4 ,the stratifications are greatly intensified by the presence of a little vapor of turpentine1 alcohol1 bisulphide of carbon and other substances4 ,stray ,field4 ,in a dynamo or motor the portion of the field whose lines of force are not cut by the armature windings4 ,stray ,power4 ,the proportion of the energy wasted in driving a dynamo1 lost through friction and other hurtful resistances4 ,streamlets1 ,current4 ,a conception bearing the same relation to an electric current that lines of force do to a field of force2 elementary currents4 ,if evenly distributed the current is of uniform density2 if unevenly distributed1 as in alternating currents1 the current density varies in different parts of the cross section of the conductor4 ,this evenness or unevenness may be referred to the number of streamlets per unit of area of cross-section4 ,transcriber's note3 ,streamlets per unit of area is redundant with current density4 ,stress4 ,force exercised upon a solid tending to distort it1 or to produce a strain4 #dif ,,standard ,,electrical ,,dictionary4 ,stress1 ,dielectric4 ,the condition of a dielectric when maintaining a charge2 its two extremities are in opposite states of polarity1 or are under permanent potential difference4 ,as the two opposite polarities tend to unite a condition of stress is implied in the medium which separates them4 ,stress1 ,electro-magnetic4 ,the stress produced upon transparent substances in an electro-magnetic field of force4 ,it is shown in the modified optical properties of glass and similar substances placed between the poles of a strong electro-magnet4 ,stress1 ,electrostatic4 ,the stress produced upon substances in an electrostatic field of force2 the exact analogue of electro-magnetic stress1 and affecting transparent substances in the same general way4 ,striae1 ,electric4 ,in ,geissler tubes the light produced by the electric discharge is filled with striae1 bright bands alternating with dark spaces2 these may be termed electric striae4 ,striking ,distance4 ,the distance that separates two conductors charged with electricity of different potential1 when a spark starts between them4 ,striking ,solution4 ,in silver-plating a bath composed of a weak solution of silver cyanide-with a large proportion of free potassium cyanide4 ,it is used with a strong current and a large silver anode4 ,this gives an instantaneous deposition of metallic silver over the surface of the article which goes to insure a perfect coating in the silver bath proper4 ,after a few seconds in the striking solution1 the article is at once removed to the plating bath4 ,stripping4 ,the removal of electroplating from an object4 ,it may be effected in several ways4 ,an object whose plating is to be removed is placed in a plating bath of the solution of the metal with which it is coated4 ,it is connected as the anode to the positive plate of the battery or corresponding terminal of the generator4 ,a kathode connected to the other terminal being placed in the bath1 the coating is dissolved by electrolytic action4 ,sometimes simple treatment with acid is employed4 ,different stripping baths are described under the heads of the different metals4 ,s4 ,u4 ,symbol or abbreviation for ,siemens' ,unit of ,resistance4 7,see ,resistance1 ,siemens' ,unit of47 ,sub-branch4 ,a branch or lead of wire taken from a branch lead3 a term used in electric distribution4 ,sub-main4 ,in electric distribution a conductor connected directly to a main2 a branch4 #dig ,,standard ,,electrical ,,dictionary4 ,subway1 ,electric4 ,a subterranean system of conduits for electric cables4 ,as generally constructed in this country it includes manholes1 q4 v41 at the street corners connected by ducts or pipes4 ,these pipes are large enough to hold a cable4 ,to introduce a cable into a duct1 which latter may be two or three inches in diameter1 and from two hundred to six or seven hundred feet long1 a wire or rope is first passed through the duct4 ,this is done by a set of short wooden rods with screws at the end so as to be screwed together4 ,each rod must be shorter than the diameter of the manhole4 ,a rod is thrust in1 another is screwed to it and thrust in1 and thus a set of rods is made to extend as far as desired4 ,in pulling them out a rope is attached and drawn through4 ,this rope or a larger one is used in drawing the cable through the duct4 ,a windlass is employed to draw the rope with cable attached through the ducts4 ,sulphating4 ,in storage battery cells1 the formation of a hard white basic lead sulphate1 ,pb#b ,s#je4 ,its formation is due to over-exhaustion of the cells4 ,as long as the voltage is not allowed to fall below #a4ij volts per cell little of it forms4 ,as it accumulates it is apt to drop off the plate and fall to the bottom1 thus weakening the plate possibly1 and depriving it of active material1 and clogging up the cell4 ,if it carries a film of metallic lead with it1 there is danger of short circuiting the cell4 ,the presence of some sodium sulphate in the solution is said to tend to prevent sulphating1 or to diminish it4 ,sulphur ,dioxide4 ,a compound gas1 ,s ,o#b2 composed of ,sulphur1 #cb ,oxygen1 #cb ,molecular weight1 #fd ,specific gravity1 #b4ba4 ,it is a dielectric of about the same resistance as air4 ,its specific inductive capacity at atmospheric pressure is3 #a4jjcg 7,ayrton74 ,synonyms--,sulphurous ,acid--,sulphurous ,acid ,gas4 ,sunstroke1 ,electric4 ,exposure to the arc light sometimes produces the effects observed in cases of sunstroke4 ,it is said that1 in the case of workmen at electric furnaces1 these effects are very noticeable4 7,see ,prostration1 ,electric47 ,transcriber's note3 ,effects are due to ultraviolet light4 ,supersaturated4 adj4 ,a liquid is supersaturated when it has dissolved a substance at a temperature favorable to its solubility and its temperature has been allowed to change1 the liquid being kept free from agitation or access of air1 provided crystallization or precipitation has not taken place4 ,it expresses the state of a liquid when it holds in solution more than the normal quantity of any substance soluble in it4 ,surface4 ,a galvanic battery is arranged in surface when all the positive plates are connected together and all the negative plates are also connected4 ,this makes it equivalent to one large cell1 the surface of whose plates would be equal to the aggregate surface of the plates of the battery4 ,it is also used as an adjective1 as a surface arrangement of battery4 #dih ,,standard ,,electrical ,,dictionary4 ,surface ,density4 ,the relative quantity of an electric charge upon a surface4 ,surface1 ,equipotential4 ,a surface over all of which the potential is the same4 ,in a general sense equipotential surfaces are given by planes or surfaces which cut lines of force at right angles thereto1 or which are normal to lines of force4 ,the conception applies to electrostatic and electro-magnetic fields of force1 and for current conductors the planes normal to the direction of the current are equipotential surfaces4 ,the contour of an equipotential surface of a field of force which is drawn or represented by delineations of its lines of force can be obtained by drawing a line normal thereto4 ,this line will ordinarily be more or less curved1 and will be a locus of identical potentials4 ,an electric equipotential surface may be described as electro-static1 electro- magnetic1 or magnetic2 or may be an equipotential surface of a current conductor4 ,besides these there are mechanical and physical equipotential surfaces1 such as those of gravitation4 ,surface ,leakage4 ,leakage of current from one part of an insulating material to another by the film of moisture or dirt on the surface4 ,suspension4 ,this term is applied to methods of supporting galvanometer needles1 balance beams1 magnetic compass needles and similar objects which must be free to rotate4 7,see ,suspension1 ,bifilar--,fibre and ,spring ,suspension--,fibre ,suspension--,knife ,edge ,suspension--,pivot ,suspension--,suspension1 ,torsion47 #cjh4 ,,diagram ,,of ,,bifilar ,,suspension4 ,suspension1 ,bifilar4 ,suspension by two vertical parallel fibres1 as of a galvanometer needle4 ,the restitution force is gravity1 the torsion being comparatively slight and negligible4 ,leaving torsion out of account the restitution force is 7a7 proportional to the distance between the threads24 7b7 inversely proportional to their length2 7c7 proportional to weight of the needle or other object suspended2 7d7 proportional to the angle of displacement4 #dii ,,standard ,,electrical ,,dictionary4 ,assume two masses ,a and ,b at the end of a weightless rod1 suspended by the parallel cords a ,a1 b ,b4 ,let the rod be rotated through an angle theta4 ,consider the cord a ,a4 ,its lower end is swung through the angle theta1 as referred to the center ,o2 the cord is deflected from the vertical by an angle psi1 such that a ,a tang7psi7 ,o ,a #b sin 7theta_/#b74 ,the component of gravitation tending to restore ,a to ,a1 acting towards ,a is equal to m g tan7psi74 ,its moment around ,o is equal to 7m g tan7psi77 99 7,o ,a cos7theta_/#b74 ,the whole moment of the couple is #b m g tan7psi74 #j ,a4 cos7theta_/#b7 #b m g 7,o ,a#b_/ a ,a7 #b sin7theta_/#b74 ,cos7theta_/#b7 #bmgl7,,oa#b_/;a,a7 sin7theta74 ,the moment of the restoring force is thus proportional to the sine of the angle of deflection1 and the oscillations of such a system are approximately simple harmonic4 7,daniell47 ,if the twisting is carried so far as to cause the threads to cross and come in contact with each other the suspension ceases to be a bifilar suspension1 but assumes the nature of a torsional suspension4 ,transcriber's note3 ,this is the image of the first paragraph4 ,swaging1 ,electric4 ,mechanical swaging in which the objects to be swaged are heated by an electric current as in electric welding4 ,s4 ,w4 ,g4 ,abbreviation for ,standard ,wire ,gauge4 ,fig4 #cji4 ,,simple ,,switch4 ,switch4 ,a device for opening and closing an electric circuit4 ,a simple type is the ordinary telegrapher's switch4 ,a bar of metal is mounted horizontally by a pivot at one end1 so as to be free to rotate through an arc of a circle4 ,in one position its free end rests upon a stud of metal4 ,one terminal of a circuit is attached to its journal1 the other to the stud4 ,resting on the stud it closes the circuit1 in other positions it opens the circuit4 #ejj ,,standard ,,electrical ,,dictionary4 ,switch1 ,automatic4 ,a switch opened and closed by the electric current4 ,it is used for lighting distant incandescent lamps4 ,it includes one or two electro-magnets operated by two push buttons4 ,in the usual arrangement one button is black and the other white1 for extinguishing and lighting respectively4 ,when the white button is pushed it causes a current to pass through one of the electro-magnets4 ,this attracts its armature1 thereby making a contact and throwing the lamps into the lighting circuit4 ,then they remain lighted until the black button is pressed4 ,this excites the other magnet1 which attracts its armature1 breaks the contact and extinguishes the lights4 ,the object of the automatic switch is to enable distant lamps to be lighted without the necessity of carrying the electric leads or wires to the place whence the lighting is to be done4 ,a very small wire will carry enough current to operate the magnets1 and open circuit batteries1 such as ,leclanch batteries1 may be used as the source of current for the switch1 but generally the lighting current is used for the purpose4 ,a single magnet may do the work4 ,when the lighting button is pressed the magnet is excited1 attracts its armature and holds it attracted1 until by pressing the black button the current is turned off from it4 ,in this case the lighting current is used to excite the magnet4 ,switch ,board4 ,a board or tablet to which wires are led connecting with cross bars or other switching devices1 so as to enable connections among themselves or with other circuits to be made4 ,switch1 ,circuit ,changing4 ,a switch whose arm in its swing breaks one contact and swinging over makes another4 ,it is employed to change the connections of circuits from one dynamo to another4 ,synonyms--,changing ,switch--,changing ,over ,switch4 ,switch1 ,double ,break4 ,a form of switch in which double contact pieces are provided to give a better contact4 ,one form consists of a hinged bar whose end swings down between two pairs of springs4 ,both pairs are connected to one terminal1 and the bar to the other terminal of a circuit4 ,switch1 ,double ,pole4 ,a heavy switch for central station work1 that connects and disconnects two leads simultaneously4 ,switch1 ,feeder4 ,a heavy switch1 often of double contact type1 for connecting and disconnecting feeders from bus bars in central stations4 #eja ,,standard ,,electrical ,,dictionary4 ,switch1 ,knife4 ,a switch whose movable arm is a narrow1 deep bar of copper or brass1 and which in making contact is forced in edgeways between two springs connected to one terminal4 ,the bar is connected to the other terminal4 ,synonyms--,knife ,break ,switch--,knife ,edge ,switch4 ,switch1 ,multiple4 ,a switch which in the swing of its bar connects one by one with a number of contacts so that ultimately the end of its bar is in contact with all at once4 ,it is used to throw lights in and out in succession1 and it can1 if the multiple contacts connect with resistances1 make them operate as a rheostat4 ,switch1 ,pole ,changing4 ,a switch for changing the direction of the current in a circuit4 ,switch1 ,reversing4 ,a switch1 often of the plug type 7see ,plug ,switch7 for changing the direction of current passing through a galvanometer4 ,switch1 ,snap4 ,a switch constructed to give a quick1 sharp break4 ,it has a spiral spring interposed between the handle and arm4 ,as the handle is drawn back to open it the spring is first extended1 the bar being held by the friction of the contacts1 until the spring suddenly jerks it up1 thus breaking the contact4 ,switch1 ,storage ,battery ,changing4 ,a switch for changing storage battery connections from series to multiple and back again4 ,switch1 ,three ,way4 ,a switch1 so constructed that by turning its handle connection can be made from one lead to either of two other leads1 and also so that connection can be completely cut off4 ,sympathetic ,vibration4 ,the establishment of periodic movement in one body by impulses of the same period communicated to it from another body in motion4 ,thus if two tuning forks are of the same pitch and one is sounded the other will begin to sound by sympathy1 the sound waves communicating the necessary periodic impulses to it4 ,sympathetic vibrations are utilized in harmonic telegraphy4 7,see ,harmonic ,receiver--,telegraph1 ,harmonic47 ,t4 ,symbol of time4 ,tailings4 7a7 ,in high speed transmission of telegraph signals by the automatic system1 the definiteness of the signal marks is sometimes interfered with by retardation4 ,wrong marks are thus produced called tailings4 7b7 ,the prolongation of the current at the distant receiving station of a telegraph line due to the discharge of the line and to self-induction4 ,synonyms--,tailing--,tailing ,current4 #ejb ,,standard ,,electrical ,,dictionary4 ,tamidine4 ,reduced nitro-cellulose4 ,nitro-cellulose is dissolved in a proper solvent and is obtained by evaporation as a translucent solid mass4 ,by ammonium sulphide or other reagent it is reduced so as to be virtually cellulose4 ,it is cut into shape for filaments of incandescent lamps1 which shapes are carbonized and flashed4 ,tangent ,law4 ,in a galvanometer the tangents of the angles of deflection of the needle are proportional to the deflecting force-- ,i4 ,when the controlling force is unaltered in absolute magnitude and direction by the motion of the needle4 ,,ii4 ,when the deflecting force acts at right angles always to the controlling force4 ,these conditions are usually secured by having the actuating coil through which the current passes flat and of large diameter compared to the length of the needle2 by using the uniform field of the earth as the control2 by having a short needle2 by placing the coil with its plane in the magnetic meridian4 ,for best proportions of tangent galvanometer coils see ,bobbins4 ,fig4 #caj4 ,,graphic ,,construction ,,of ,,tangent ,,scale4 ,tangent ,scale4 ,an arc of a circle in which the number of graduations in any arc starting from zero are proportional to the tangent of the angle subtended by such arc4 ,the system is for use with tangent galvanometers4 ,thus if for #de a value of #ajj is taken and marked on the scale then for the arc #bf #cc' a value of #ej should be marked on the scale because such are the relative values of the tangents4 ,thus the scale instead of being divided into degrees is divided into arcs of varying length1 growing shorter as they are more distant from the zero point1 of such length that the first division being subtended by a tangent of length #a1 the first and second divisions added or taken together as one arc are subtended by a tangent of length #b1 and so on4 ,in the cut a simple method of graphically laying out a tangent scale is shown4 ,in it ,c is the centre of the arc1 and ,h the radius running to the zero of the instrument4 ,from ,c a circle is described and on ,h a vertical line tangent to the arc is erected4 ,taking any part of the tangent1 as the length shown ending at ,d1 it is divided into any number of equal parts4 ,radii of the circle are now drawn whose prolongations pass through the divisions on the tangent4 ,these radii1 where they intersect the arc of the circle1 determine equal divisions of the tangent scale1 which1 as is evident from the construction1 are unequal angular divisions of the arc4 #ejc ,,standard ,,electrical ,,dictionary4 ,tanning1 ,electric4 ,the tanning of hides in the manufacture of leather by the aid of electrolysis4 ,a current of electricity is maintained through the tanning vats in which regular tanning liquor is contained4 ,very extraordinary claims are made for the saving of time in the tanning process4 ,what is ordinarily a process of several months1 and sometimes of a year1 is said to be reduced to one occupying a few days only4 ,the action of electrolysis is the one relied on to explain the results4 ,tapper4 ,the key used in single needle telegraph transmitters4 ,it comprises two flat springs ,l1 ,e1 each with a handle1 normally pressed upward against one contact bar ,z1 and when pressed down by the operator making contact against a lower bar ,c when messages are to be transmitted4 ,a double tapper1 such as shown1 is used for each instrument4 ,synonyms--,double ,tapper ,key--,pedal ,key4 ,fig4 #caa4 ,,tapper4 ,target1 ,electric4 ,a target registering or indicating electrically upon an annunciator the point of impact of each bullet4 ,taste1 ,galvanic4 ,the effect produced upon the gustatory nerves by the passage of an electric current1 or by the maintenance of potential difference between two portions of the tongue4 ,it is very simply produced by placing a silver coin above1 and a piece of zinc below the tongue1 or the reverse1 and touching their edges4 ,a sour1 peculiar taste is at once perceived4 ,it cannot be due to any measurable quantity of current or of electrolytic decomposition1 because the couple can do little more than establish a potential difference4 ,with a strong current the taste becomes too strong for comfort1 and if on a telegraph line the extra currents produced by the signaling make the operation of tasting the current a very unpleasant one4 ,it is said that messages have been received in this way1 the receiver placing one terminal of the line on his tongue1 and a terminal attached to a grounded wire below it1 and then receiving the ,morse characters by taste4 #ejd ,,standard ,,electrical ,,dictionary4 ,teazer4 ,originally a fine wire coil wound on the field magnets of a dynamo in shunt with the regular winding to maintain the magnetism4 ,it was originally used in electroplating machines to prevent inversion of the magnetism1 but has since developed into a component part of the winding of the compound dynamo4 7,see ,dynamo1 ,compound47 ,tee1 ,lead4 ,a lead pipe of ,t shape used for connecting branches to electric cables4 ,the tee is soldered by wiped joints to the lead sheathings of the cable and branches after the wires have been connected1 and the junctions coated with insulating tape or cement1 or both4 ,it is sometimes made in two halves1 and is known as a split tee4 ,tel-autograph4 ,a telegraph for reproducing the hand-writing of the sender at the receiving end of the line4 ,to save time a special spelling is sometimes used4 ,teleautograph4 ,the special spelling used with the ,tel-,autograph telegraph4 ,tele-barometer1 ,electric4 ,a barometer with electric attachment for indicating or recording at a distance the barometric readings4 ,telegraph1 ,,abc4 ,this term is applied to alphabet telegraphs indicating the message by the movements of a pointer on a dial marked with the characters to be sent4 ,in ,england the ,wheatstone ,,abc system is much employed4 ,telegraph1 ,automatic4 ,a telegraph system based on the operation of the transmitting instrument by a perforated strip of paper drawn through it4 ,the perforations made by an apparatus termed a perforator1 are so arranged as to give telegraphic characters of the ,morse or ,international ,code in the transmitting instrument4 7,see ,perforator47 ,bain in the year #ahdf was the originator of the system4 ,he punched a fillet of paper with dots and dashes1 and drew it between two terminals of the line1 thus sending over the line a corresponding series of short and long currents which were received by his chemical receiver4 7,see ,chemical ,receiver47 ,the method was not successful4 ,its modern development1 the ,wheatstone ,automatic ,telegraph1 is highly so4 ,the perforated paper by its perforations controls the reciprocating movement of two rods1 which pass through each hole in two rows1 corresponding to the two rods respectively as the holes come opposite to the ends of the rods4 ,the rods are kept constantly moving up and down4 ,if unperforated paper is above them their upward motion is limited4 ,this gives three positions for the rods1 7a7 both down1 7b7 one up and the other down1 7c7 both up4 ,these positions of the rods work a pole changing key by which dots1 spaces1 and dashes are transmitted to the receiving instrument1 which is an exceedingly delicate ink-printer4 ,the latter can have its speed adjusted to receive from #bjj to #dej words per minute4 #eje ,,standard ,,electrical ,,dictionary4 ,telegraph1 ,dial4 ,a telegraph in which as receiver a dial instrument is used4 ,a pointer or index hand moves around a dial4 ,the dial is marked with letters of the alphabet4 ,the movements of the pointer are controlled by the transmitting operator at a distant station4 ,he by the same actions moves a pointer on a duplicate instrument before him and the two are synchronized to give identical indications4 ,thus a message is spelled out letter by letter on both dials simultaneously4 ,the motions of the index are generally produced by what is virtually a recoil escapement4 ,the scape wheel is carried by the axle of the index1 and a pallet or anchor is vibrated by an electro-magnet whose armature is attached to the stem of the pallet4 ,as the pallet is vibrated it turns the wheel and index one tooth for each single movement4 ,there are as many teeth in the wheel as there are characters on the dial4 ,the two instruments being in duplicate and synchronized1 the pallets move exactly in unison1 so that identical readings of the dials are given4 ,the pallets may be moved by any kind of make and break mechanism1 such as an ordinary telegraph key4 ,the index moves by steps or jerks1 so that the system is sometimes called step-by-step telegraphy4 ,fig4 #cab4 ,,dial ,,telegraph4 ,in the cut the make and break transmitter is shown at v v1 with its handle and contacts g and t4 ,this mechanism sends impulses of current by ,f and ,z to the receiving magnet l4 ,this attracts and releases its armature ,k from contact into the position indicated by the dotted lines4 ,this works the rocker n on the pin o1 and actuates the double or anchor pawl s r1 which turns the pallet or scrape wheel m4 ,the system is dropping into disuse1 being supplanted by the telephone4 ,synonym--,step-by-step ,telegraph4 #ejf ,,standard ,,electrical ,,dictionary4 ,telegraph1 ,double ,needle4 ,a telegraph system in which the message is read by the motions of two vertical needles on the face of the instrument in front of the receiving operator4 ,an identical instrument faces the transmitting operator4 ,by two handles1 one for each hand1 the needles are caused by electric impulses to swing to right and to left so as to give a telegraphic code4 ,it has been generally superseded by the single needle telegraph4 ,telegraph1 ,duplex4 ,a telegraph capable of transmitting simultaneously two messages over one wire4 ,the methods of effecting it are distinct from those of multiplex telegraphy4 ,this term is used as a distinction from diode multiplex telegraphy1 in which the work is done on other principles4 ,there are two systems of duplex telegraphy1 the differential and the bridge systems4 ,telegraph1 ,duplex ,bridge4 ,a system of duplex telegraphy employing the principle of the ,wheatstone bridge4 ,the other or differential system depends on equality or difference of currents2 the bridge method on equality or difference of potentials4 ,the cut shows the system known as ,steam's ,plan4 ,at the ends of the line wire are two cross connections like duplicate galvanometer connections in a ,wheatstone bridge1 each including a receiving relay4 ,the rest of the connections are self-explanatory4 ,when ,a depresses his key the current splits at the point indicating the beginning of the bridge4 ,one portion goes through the line to ,b and to earth1 the other goes to earth at ,a through the rheostats indicated by the corrugated lines4 ,on reaching ,b's end the current divides at the cross-connection and part goes through the receiving relay shown in the center of that cross-connection4 ,thus if ,a sends to ,b or ,b to ,a it is without effect on the home receiving instrument4 ,now suppose that both simultaneously are sending in opposite directions4 ,if the connections be studied it will be seen that every movement of the transmitting key will affect the balance of the distant or receiving end of the bridge and so its instrument will record the signals as they are sent4 ,as shown in the cut the sending keys are on local circuits1 and work what are known as duplex transmitters4 ,these are instruments which send line signals without breaking the connection4 ,fig4 #cac4 ,,stearn',s ,,plan ,,of ,,duplex ,,bridge ,,telegraphy4 ,in ,stearn's plan condensers are introduced as shown4 ,by this plan different receiving instruments can be used4 ,the inventor once worked a ,morse instrument at one end of the line1 and a ,hughes' instrument at the other end4 #ejg ,,standard ,,electrical ,,dictionary4 ,telegraph1 ,duplex1 ,differential4 ,a system of duplex telegraphy employing the differential action of two exciting or magnetizing coils4 ,the general principles are the following4 ,suppose that at each of two stations1 there is a magnet working as a sounder or relay4 ,each magnet is differentially wound1 with two coils of opposite direction1 of identical number of turns4 ,when the sending key at a station ,a is depressed two exactly equal currents go through the magnet in opposite directions4 ,one called the compensation current goes to the earth at the stations4 ,the other called the line current goes through the line1 through the line coil of the distant station ,e1 thereby actuating the relay or sounder armature4 ,the instrument of the sender ,a is unaffected because he is sending opposite and equal currents through its two coils4 ,a special resistance is provided on the compensation circuit for keeping the currents exactly equal in effect4 ,nothing the sender at ,a does affects his own instrument4 ,now suppose ,e desires to telegraph back at the same time that ,a is telegraphing to his station4 ,he works his key4 ,this does not affect his own instrument except by sending the equal and opposite currents through its coils4 ,when his key is depressed and ,a's key is untouched1 he works ,a's receiving instrument4 #ejh ,,standard ,,electrical ,,dictionary4 ,when ,a's key is depressed simultaneously with ,b's key1 the two line currents are in opposition and neutralize each other4 ,this throws out the balance in the instruments and both armatures are attracted by the compensation currents left free to act by the neutralization of the line currents4 ,fig4 #cad4 ,,duplex ,,telegraph1 ,,differential ,,system ,suppose that ,b is sending a dash1 and it begins while ,a's key is raised4 ,the line and compensation currents in ,b's receiving instrument neutralize each other and no effect is produced1 while ,a's receiving instrument begins to register or indicate a dash4 ,now suppose ,a starts to send a dash while ,b's is half over4 ,he depresses his key4 ,this sends the two opposite currents through his magnet4 ,his line current neutralizes ,b's working current so that the compensation currents in both receiving instruments hold the armatures attracted for the two dashes4 ,meanwhile ,a's dash ends and he releases his key4 ,at once his line current ceases to neutralize ,b's line current1 his receiving instrument is actuated now by ,b's line current1 while ,b's receiving instrument ceases to be actuated by the compensation current4 ,two assumptions are made in the above description4 ,the line currents are assumed to be equal in strength and opposite in direction at each station4 ,neither of these is necessary4 ,the line current received at a station is always weaker than the outgoing line current1 and it is the preponderance of the compensation current over the partly neutralized line current that does the work4 ,as this preponderance is very nearly equal to the line current received from the distant station1 the signals are actuated by almost the same current1 whether it is compensation or line current4 #eji ,,standard ,,electrical ,,dictionary4 ,both line currents may coincide in direction4 ,then when the two keys are depressed1 a line current of double strength goes through both receiving instruments and both work by preponderance of the double line current over the compensation current4 ,in other respects the operation is the same as before described4 ,fig4 #cae4 ,,duplex ,,telegraph1 ,,differential ,,system4 ,fig4 #caf4 ,,differential ,,duplex ,,telegraph ,,connections4 ,the cut shows a diagram of the operation of one end of the line4 ,r and ,r are resistances1 ,e and ,e are earth contacts1 and the two circles show the magnet of the receiving instrument wound with two coils in opposition4 ,the battery and key are also shown4 ,it also illustrates what happens if the key of the receiver is in the intermediate position breaking contact at both #a and #b4 ,the sender's line current then goes through both coils of the receiving instrument magnet1 but this time in series1 and in coincident direction4 ,this actuates the instrument as before4 ,owing to the resistance only half the normal current passes1 but this half goes through twice as many coils or turns as if the receiver's key was in either of the other two positions4 ,in actual practice there are many refinements4 ,to compensate for the varying resistance of the line a rheostat or resistance with sliding connection arm is connected in the compensation circuit so that the resistance can be instantly changed4 ,as the electro-static capacity of the line varies sectional condensers are also connected in the compensation circuits4 #eaj ,,standard ,,electrical ,,dictionary4 ,telegraph1 ,facsimile4 ,a telegraph for transmitting facsimiles of drawing or writing4 ,the methods employed involve the synchronous rotation of two metallic cylinders1 one at the transmitting end1 the other at the receiving end4 ,on the transmitter the design is drawn with non-conducting ink4 ,a tracer presses upon the surface of each cylinder and a circuit is completed through the two contacts4 ,in operation a sheet of chemically prepared paper is placed over the surface of the receiving cylinder4 ,the two cylinders are rotated in exact synchronism and the tracers are traversed longitudinally as the cylinders rotate4 ,thus a number of makes and breaks are produced by the transmitting cylinder1 and on the receiving cylinder the chemicals in the paper are decomposed1 producing marks on the paper exactly corresponding to those on the transmitting cylinder4 ,synonyms--,autographic ,telegraph--,pantelegraphy4 ,telegraph1 ,harmonic ,multiplex4 ,a telegraph utilizing sympathetic vibration for the transmission of several messages at once over the same line4 ,it is the invention of ,elisha ,gray4 ,the transmitting instrument comprises a series of vibrating reeds or tuning-forks1 each one of a different note1 kept in vibration each by its own electro-magnet4 ,each fork is in its own circuit1 and all unite with the main line so as to send over it a make and break current containing as many notes superimposed as there are tuning forks4 ,at the other end of the line there are corresponding tuning forks1 each with its own magnet4 ,each fork at this end picks up its own note from the makes and breaks on the main line1 by the principle of sympathetic vibration4 ,to each pair of operators a pair of forks of identical notes are assigned4 ,as many messages can be transmitted simultaneously as there are pairs of forks or reeds4 ,the movements of a telegraph key in circuit with one of the transmitting reeds sends signals of the ,morse alphabet1 which are picked out by the tuning fork of identical note at the other end of the line4 #eaa ,,standard ,,electrical ,,dictionary4 ,telegraph1 ,hughes'4 ,a printing telegraph in very extensive use in continental ,europe4 ,its general features are as follows3 ,the instruments at each end of the line are identical4 ,each includes a keyboard like a piano manual1 with a key for each letter or character4 ,on each machine is a type wheel1 which has the characters engraved in relief upon its face4 ,with the wheel a chariot as it is termed also rotates4 ,the type wheels at both stations are synchronized4 ,when a key is depressed1 a pin is thrown up which arrests the chariot1 and sends a current to the distant station4 ,this current causes a riband of paper to be pressed up against the face of both type wheels so as to receive the imprint of the character corresponding to the key4 ,the faces of the wheels are inked by an inking roller4 ,fig4 #cag4 ,,electro-,,magnet ,,of ,,hughes' ,,printing ,,telegraph4 ,the most characteristic feature is the fact that the current sent by depressing a key does not attract an armature1 but releases one1 which is then pulled back by a spring4 ,the armature is restored to its position by the mechanical operation of the instrument4 ,the magnet used is a polarized electro-magnet4 ,coils are carried on the ends of a strong powerful magnet4 ,the coils are so connected that a current sent through them by depressing a key is in opposition to the magnetism of the permanent magnet so that it tends to release the armature1 and in practice does so4 ,this release permits the printing mechanism to act4 ,the latter is driven by a descending weight1 so that very slight electric currents can actuate the instruments4 ,synonym--,hughes' ,type ,printer4 ,telegraphic ,code4 7a7 ,the telegraphic alphabet1 as of the ,morse ,system4 7,see ,alphabet1 ,telegraphic47 7b7 ,a code for use in transmitting messages either secretly1 or comprising several words or short sentences in one word1 in order to economize in transmission4 ,such codes are extensively used in commercial cable messages4 #eab ,,standard ,,electrical ,,dictionary4 ,telegraph1 ,magneto-electric4 ,a telegraph in which the current is produced by magneto-electric generators4 ,it has been applied to a considerable extent in ,england4 ,the ,wheatstone ,,abc or dial telegraph is operated by a magneto-generator turned by hand4 ,in this country the magneto-electric generator by which the calling bell of a telephone is rung is an example4 ,the magneto-electric key 7,see ,key1 ,magneto-electric7 is for use in one kind of magneto-electric telegraphing4 ,telegraph1 ,morse4 ,a telegraph1 characterized by the use of a relay1 working a local circuit1 which circuit contains a sounder1 or recorder for giving dot and dash signals constituting the ,morse alphabet4 ,the signals are sent by a telegraph key1 which when depressed closes the circuit1 and when released opens it4 ,the two underlying conceptions of the ,morse ,telegraph system are the use of the dot and dash alphabet1 and the use of the local circuit1 which circuit includes a receiving instrument1 and is worked by a relay1 actuating a local battery4 ,it would be difficult to indicate any invention in telegraphy which has had such far-reaching consequences as the one known as the ,morse telegraph4 ,in other places the principal apparatus of the system will be found described4 ,the cut ,fig4 #cah1 repeated here gives the general disposition of a ,morse system4 7,see ,circuit1 ,local47 ,fig4 #cah4 ,,diagram ,,of ,,morse ,,system4 #eac ,,standard ,,electrical ,,dictionary4 ,the key by which the messages are transmitted is shown in ,fig4 #cai4 ,m is a base plate of brass4 ,a is a brass lever1 mounted on an arbor ,g carried between adjustable set screws ,d4 ,c is the anvil where contact is made by depressing the key by the finger piece ,b of ebonite4 ,e1 ,fl are adjusting screws for regulating the vertical play of the lever4 ,h is the switch for opening or closing the circuit4 ,it is opened for transmission1 and closed for receiving4 ,by screws1 ,l ,l1 with wing nuts1 ,k ,k1 the whole is screwed down to a table4 ,fig4 #cai4 ,,morse ,,telegraph ,,key4 ,in the ,united ,states the simplest disposition of apparatus is generally used4 ,the main line is kept on closed circuit4 ,in it may be included a large number of relays at stations all along the line1 each with its own local circuit4 ,there may be fifty of such stations4 ,battery is generally placed at each end of the line4 ,very generally gravity batteries are used1 although dynamos now tend to supplant them in important stations4 ,as relays the ordinary relay is used4 ,its local circuit includes a sounder and local battery4 ,the latter is very generally of the gravity type1 but oxide of copper batteries 7,see ,battery1 ,oxide of ,copper7 are now being introduced4 ,at main or central offices1 the terminals of the lines reach switch boards1 where by spring-jacks and plugs1 any desired circuits can be looped into the main circuit in series therewith4 ,in ,european practise the main line is kept on open circuit4 ,polarized relays are used to work the local circuits4 ,the currents for these have to be alternating in direction4 ,when the line is not in use its ends are connected to earth at both ends1 leaving the battery out of circuit4 ,each intermediate station has its own main1 or line battery for use when it desires to send a message4 ,in the ,american system as first described1 it will be seen that the main batteries are at most two in number4 ,for the details of the different apparatus1 the following definitions may be consulted3 ,embosser1 ,telegraphic--,recorder1 ,morse--,relay--,relay ,connection--,sounder4 #ead ,,standard ,,electrical ,,dictionary4 ,telegraph1 ,multiplex4 ,a system of telegraphy by which a number of messages can be transmitted in both directions over a single wire4 ,the principles underlying the systems are the following3 ,suppose that at the two extremities of a telegraph line two arms are kept in absolute synchronous rotation4 ,let the arms in their rotation1 press upon as many conducting segments as there are to be transmissions over the line4 ,a transmitting and receiving set of instruments may be connected to one segment at one end of the line1 and another set to the corresponding segment at the distant station4 ,for each pair of segments two sets can be thus connected4 ,then if the arm rotates so rapidly that the contacts succeed each other rapidly enough each pair of sets of instruments can be worked independently of the others4 ,in practice this rapid succession is effected by having a number of contacts made for each pair during a single rotation of the arm or equivalent4 ,the multiplex system has been perfected by the use of ,la ,cour's phonic wheel 7see ,phonic ,wheel71 and brought into a practical success by ,patrick ,b4 ,delany1 of ,new ,york4 ,two phonic wheels rotate at each end of the line4 ,they are kept in synchronous motion by two vibrating steel reeds of exactly the same fundamental note1 and the axle of each wheel carries an arm whose end trails over the contacts or distributor segments already spoken of4 ,the reeds are adjusted to vibrate at such speed that the trailer is in contact with each segment about #a_/ejj second4 ,the number of groups of segments required for each working is determined by the retardation of the signals owing to the static capacity of the line4 ,to convert the rapidly recurring impulses of current into practically a single current1 condensers are connected across the coils of the relay4 ,one battery serves for all the arms4 ,multiplex telegraphy can effect from two to six simultaneous transmissions over one wire4 ,for two or four transmissions the method only distinguishes it from duplex or quadruplex telegraphy4 ,the terms diode1 triode1 tetrode1 pentode and hexode working are used to indicate respectively the simultaneous transmission of two1 three1 four1 five1 or six messages over one wire4 ,it will be seen that the multiplex process really assigns to each transmission separate times1 but divides these times into such short and quickly recurring intervals that the work is executed as if there was continuous contact4 ,in no case is there the popular conception of the sending of several messages actually simultaneously over one wire4 ,each signal in reality has its own time assigned it1 divided into short periods of high frequency1 and only utilizes the line when it is free4 #eae ,,standard ,,electrical ,,dictionary4 ,telegraph1 ,over-house4 ,an ,english term for telegraph lines led over houses and supported on standards on the roofs4 ,telegraph ,pole ,brackets4 ,arms for carrying insulators1 which arms are attached to telegraph poles or other support4 ,they vary in style2 sometimes they are straight bars of wood gained into and bolted or spiked in place2 sometimes they are of iron4 ,telegraph1 ,printing4 ,various telegraphs have been invented for printing in the ordinary alphabet the messages at the receiving end of the line4 ,representative instruments of this class are used for transmitting different market and stock reports to business offices from the exchanges4 ,the type faces are carried on the periphery of a printing wheel1 which is rotated like the hand of a dial telegraph1 and against whose face a paper riband is pressed whenever the proper letter comes opposite to it4 ,as each letter is printed the paper moves forward the space of one letter4 ,spacing between words is also provided for4 ,in the recent instruments two lines of letters are printed on the paper one above the other4 ,in ,england1 and on the continent of ,europe1 printing instruments have received considerable use for ordinary telegraphic work4 ,hughes' type printer and ,wheatstone's ,,abc telegraph meet with extensive use there for ordinary transmission4 ,telegraph1 ,quadruplex4 ,duplex telegraphy is the sending of two messages in opposite directions simultaneously through the same wire4 ,duplex telegraphy is the sending of two messages simultaneously in the same direction4 ,the two combined constitute quadruplex telegraphy4 ,,sic ,the system was suggested by ,stark of ,vienna and ,bosscha of ,leyden in #ahee2 the successful problem was solved by ,edison in #ahgd4 ,the principle is based on the two orders of difference in electric currents2 they may vary in strength or in direction4 ,thus we may have one instrument which works with change of strength of current only1 the other with change of direction only4 ,the two can be worked together if the direction of the current can be altered without alteration of strength1 and if strength can be altered without alteration of direction4 ,double current and single current working are so combined that one relay works by one system of currents and another relay by the other system4 ,a current is constantly maintained through the line4 ,the relay operated by change in direction is a simple polarized relay which works by change of direction of current4 ,the relay operated by change in strength is the ordinary unpolarized relay4 #eaf ,,standard ,,electrical ,,dictionary4 ,for the following description and the cuts illustrating it we are indebted to ,preece and ,sivewright4 ,the cut shows the arrangement of the apparatus and connections for terminal offices4 ,sufficient table room is provided to seat four clerks4 ,the apparatus is arranged for the two senders to sit together in the centre1 the messages to be forwarded being placed between them4 ,the section on the left of the switch ,q is known as the ',a' side1 that on the right as the ',b' side of the apparatus4 ,k#a the reversing key1 reverses the direction of the current4 ,k#b is a simple key1 known as the increment key2 it is used simply to increase the strength of the current4 ,fig4 #cbj4 ,,quadruplex ,,telegraph ,,connections4 ,the way in which the keys ,k#a and ,k#b combine their action is shown by ,fig4 #cba4 ,e#a and ,e#b are the line batteries1 the one having two and one-third 7#b-a_/c7 the number of cells of the other1 so that if ,e#a be the electro-motive force of the smaller1 that of the whole combined battery will be #c4c ,e#a4 ,the negative pole of ,e#a is connected to z and z#a of ,k#a and the positive pole of ,e#b to a of ,k#b through a resistance coil s4 ,a wire1 called the 'tap' wire1 connects the positive pole of ,e#a and the negative pole of ,e#b to b of ,k#b4 ,this wire has in it a resistance coil r#b4 ,the springs c and c#a of ,kl are connected to the lever ,l of ,k#b4 ,now1 when both keys are at rest1 the negative pole of ,e#a is to line through z1 and the positive pole of ,e#a to earth through b of ,k#b and c of ,k#a2 the positive pole of ,e#b being insulated at a of ,k#b4 #eag ,,standard ,,electrical ,,dictionary4 ,there is thus a weak negative current flowing to line4 ,when ,k#a alone is worked1 the current of ,e#a is reversed4 ,when ,k#b is worked alone1 c of ,k#a is transferred from b to a1 and the strength of the negative current going to line is increased through the increase of the electro-motive force from ,e#a to #c4c ,e#a for the whole battery is brought into play4 ,when ,k#a and ,k#b are depressed together1 then the negative pole of ,e#a goes to earth through ,z#a2 and the positive pole of ,e#b to line through a of ,k#b and c#a of ,k#a and a positive current1 due to the whole electro-motive force #c4c ,e#a goes to line4 ,hence the effect of working ,k#a is simply to reverse the current1 whatever its strength1 while that of ,k#b is to strengthen it1 whatever its direction4 ,the resistance coil s1 of #ajj resistance1 is called a spark coil1 because it prevents the high electro-motive force of the whole battery from damaging the points of contact by sparking or forming an arc across when signals are sent2 and the resistance r#b is made approximately equal to the combined resistance of ,e#b and the spark coil1 so that the total resistance of the circuit may not be altered by the working of the apparatus4 ,fig4 #cba4 ,,quadruplex ,,telegraph4 ,a#a and ,b#a 7,fig4 #cbj7 are the relays which are used to respond to the changes in the currents sent by the keys ,k#a and ,k#b at the distant station4 ,a1 is a simple polarized relay wound differentially1 each wire having a resistance of #bjj omega1 and so connected up as to respond to the working of the reversing key ,k#a of the distant station4 ,it acts independently of the strength of the current1 and is therefore not affected by the working of the increment key ,k#b4 ,it is connected up so as to complete the local circuit of the sounder ,s#a and the local battery l#a and forms the receiving portion of the ',a' side4 ,b1 is a non-polarized relay also wound differentially1 each coil having a resistance of #bjj omega4 ,it responds only to an increase in the strength of the current1 and therefore only to the working of the increment key ,k#b of the distant station4 ,transcriber's note3 ,in current usage upper case omega indicates ohms and lower case omega denotes angular frequency1 #b99,,pi99f4 #eah ,,standard ,,electrical ,,dictionary4 ,the relay spring is so adjusted that the armatures are not actuated by the weak current sent from ,e by the key ,k#a4 ,in its normal position this relay completes the circuit of the local battery through the sounder ,s4 ,this sounder ,s1 called the uprighting sounder1 acts as a relay to a second sounder1 ,s#b1 called the reading sounder1 which is worked by another local battery1 l#b4 ,of course1 normally1 the armature of ,s is held down and that of ,s#b is up1 but when the tongue t moves1 as it does when the increment key ,k#b is depressed so as to send the whole current to line1 then the current from l is interrupted1 and the circuit of l#b is completed by the rising of the armature of ,s1 causing the reading sounder ,s#b to work4 ,this is the ',b' side4 ,r is a rheostat for balancing the resistance of the line1 as used in duplex working4 ,c is a condenser used for compensating the static charge of the line4 ,it is provided with an adjustable retardation coil1 ,r#a1 to prolong the effect of the compensating current from the condenser4 ,g is a differential galvanometer1 used for testing1 and for facilitating adjustment and balancing4 ,q is a switch for putting the line to earth1 either for balancing1 or for any other purpose4 ,there is on the earth wire leading from ,q a resistance coil1 r#a1 equalling approximately the resistance of the whole battery1 #c4c ,e#a1 and the resistance s4 ,the connections shown in ,fig4 #cba1 are for an 'up' office4 ,at a 'down' office it is necessary to reverse the wires on the two lower terminals of the galvanometer and the two battery wires on the reversing key ,k#a4 ,the keys ,k#a and ,k#b are1 for repeaters1 replaced by transmitters4 ,the adjustment of this apparatus requires great care and great accuracy4 ,its good working depends essentially on technical skill that can only be acquired by patience and perseverance4 ,faults in working generally arise from careless adjustments1 dirty contacts1 loose connections1 battery failures1 and the ordinary line interruptions1 but there are no troubles that are beyond the reach of ordinary skill1 and it can be safely said that1 within moderate distances1 wherever and whenever duplex working is practicable1 then quadruplex working is so too4 ,the above is a typical quadruplex bridge system4 ,there is also a differential system1 the full description of which1 in addition to what has been given1 is outside of the scope of this work4 #eai ,,standard ,,electrical ,,dictionary4 ,telegraph ,repeater4 ,an extension of the relay system1 adopted for long lines4 ,a repeating station comprises in general terms duplicate repeating apparatus4 ,one set is connected for messages in one direction1 the other for messages in the opposite direction4 ,the general operation of a repeating set is as follows4 ,the signals as received actuate a relay which by its local circuit actuates a key1 which in ordinary practise would be the sounder1 but in the repeater its lever opens and closes a circuit comprising a battery and a further section of the line4 ,repeaters are placed at intervals along the line4 ,each repeater repeats the signals received for the next section of line with a new battery4 ,it represents an operator who would receive and repeat the message1 except that it works automatically4 ,the ,indo-,european line from ,london to ,teheran1 #c1hjj miles long1 is worked directly without any hand retransmission1 it being carried out by five repeaters4 ,this gives an average of over #ejj miles for each repeater4 ,transcriber's note3 ''' #fej miles for each repeater4 ,repeaters introduce retardation1 and each repeater involves a reduction in the rate of working4 ,yet in many cases they increase the speed of a line greatly1 as its speed is about equal to that of its worst section1 which may be far greater than that of the whole line in one4 ,synonym--,translater4 ,telegraph ,signal4 ,in the telegraph alphabet1 a dot1 or dash2 the signal or effect produced by one closing of the circuit4 ,a dash is equal in length to three dots4 ,the space between signals is equal to one dot2 the space between letters to three dots2 and the space between words to six dots4 ,telegraph1 ,single ,needle4 ,a telegraph system in which the code is transmitted by the movements of a needle shaped index which oscillates to right and left1 the left hand deflection corresponding to dots1 the right hand deflection to dashes4 ,the instruments for sending and receiving are combined into one4 ,the needles are virtually the indexes of vertical galvanometers4 ,in one form by a tapper key 7see ,tapper71 in another form by a key worked by a drop-handle 7the drop handle instrument71 currents of opposite directions are sent down the line4 ,these pass through both instruments1 affecting both needles and causing them to swing to right or left1 as the operator moves his key4 ,as galvanometer needle or actuating needle a soft iron needle is employed1 which is polarized by the proximity of two permanent magnets4 ,this avoids danger of reversal of polarity from lightning1 a trouble incident to the old system4 #ebj ,,standard ,,electrical ,,dictionary4 ,the cut1 ,fig4 #cbb1 shows a single needle telegraph instrument of the tapper form4 ,the action of the tapper can be understood from the next cut4 ,fig4 #cbb4 ,,single ,,needle ,,telegraph ,,instrument1 ,,double ,,tapper ,,form4 ,fig4 #cbc4 ,,double ,,tapper ,,key ,,for ,,single ,,needle ,,telegraph4 ,c and ,z are two strips of metal to which the positive and negative poles of the battery are respectively connected4 ,e and ,l are two metallic springs2 ,e is connected to earth1 ,l is connected to the line2 at rest both press against ,z4 ,if ,l is depressed so as to touch ,c1 the current from the battery goes to the line by the key ,l1 goes through the coils of the distant instrument and deflects the needle to one side1 and then goes to the earth4 ,if the key ,e is depressed1 ,l retaining its normal position1 the direction of the current is reversed1 for the other pole of the battery is connected to the earth and the reverse current going through the coils of the distant instrument deflects the galvanometer needle to the other side4 ,in the drop-handle type an analogous form of commutator worked by a single handle produces the same effects4 #eba ,,standard ,,electrical ,,dictionary4 ,telegraph1 ,wheatstone1 ,a4 ,b4 ,c4 ,a magneto-electric telegraph of the dial system4 ,an alternating current magneto-generator is turned by hand and by depressing keys its current is admitted to or cut off from the line and receiver's instrument4 ,the message is received by a dial instrument working by the escapement motion described under ,telegraph1 ,dial4 ,telegraph1 ,writing4 ,a telegraph in which the message is received in written characters4 ,the transmitter includes a stylus which is held in the hand and whose point bears against the upper end of a vertical rod4 ,the rod is susceptible of oscillation in all directions1 having at its base a spring support equivalent to a universal joint4 ,the stylus is moved about in the shape of letters4 ,as it does this it throws a series of resistances in and out of the circuit4 ,at the receiving end of the line the instrument for recording the message includes two electro-magnets with their cores at right angles to each other and their faces near together at the point of the angle4 ,an armature is supported between the faces and through it a vertical rod carried by a spring at its bottom rises4 ,these magnets receive current proportional to the resistances cut in and out by the motions of the other rod at the transmitting end of the line4 ,these resistances are arranged in two series at right angles to each other1 one for each magnet4 ,thus the movements of the transmitting stylus and rod are repeated by the end of the rod in the receiving instrument4 ,a species of pen is carried at the end of the rod of the receiving instrument1 which marks the letters upon a riband of paper which is fed beneath it4 ,telemanometer4 ,electric4 ,a pressure gauge with electric attachment for indicating or recording its indications at a distance4 ,it is applicable to steam boilers1 so as to give the steam pressure in any desired place4 ,telemeter1 ,electric4 ,an apparatus for electrically indicating or recording at a distance the indications of any instrument such as a pressure gauge1 barometer or thermometer1 or for similar work4 ,the telemanometer applied to a boiler comes into this class of instrument4 ,telephotography4 ,the transmission of pictures by the electric current1 the requisite changes in the current being effected by the action of light upon selenium4 ,the picture is projected by a magic lantern4 ,its projection is traversed by a selenium resistance through which the current passes4 ,this is moved systematically over its entire area1 thus constituting the transmitter1 and synchronously with the motion of the selenium a contact point at the other end of the line moves systematically over a sheet of chemically prepared paper4 ,the paper1 which may be saturated with a solution of potassium ferrocyanide and ammonium nitrate1 is stained by the passage of the current1 and by the variation in intensity of staining1 which variation is due to variations in the current1 produced by the effects of the light upon the selenium1 the picture is reproduced4 #ebb ,,standard ,,electrical ,,dictionary4 ,telepherage4 ,an electric transportation system1 hitherto only used for the carrying of ore1 freight1 etc4 ,its characteristic feature is that the electric conductors1 suspended from poles1 supply the way on which carriages provided with electric motors run4 ,the motors take their current directly from the conductors4 ,there are two conducting lines1 running parallel with each other1 supported at the opposite ends of transverse brackets on a row of supporting poles4 ,at each pole the lines cross over so that right line alternates with left1 between consecutive pairs of poles4 ,the cars are suspended from pulleys running on one or the other of the conductors4 ,a train of such cars are connected and the current is taken in near one end and leaves near the other end of the train4 ,these current connections are so distant1 their distance being regulated by the length of the train1 that they are1 for all but an instant at the time of passing each of the poles1 in connection with segments of the line which are of opposite potential4 ,to carry out this principle the distance between contacts is equal to the distance between poles4 ,owing to the crossing over of the lines the contacts are in connection as described and thereby the actuating current is caused to go through the motors4 ,cars running in one direction go on the electric conductors on the one side1 those running in the other direction go on the other conductor4 ,a great many refinements have been introduced1 but the system has been very little used4 ,telephone4 ,an instrument for the transmission of articulate speech by the electric current4 ,the current is defined as of the undulatory type4 7,see ,current1 ,undulatory47 ,the cut shows what may be termed the fundamental telephone circuit4 ,a line wire is shown terminating in ground plates and with a telephone in circuit at each end4 ,the latter consists of a magnet ,n ,s with a coil of insulated wire ,h surrounding one end4 ,facing the pole of the magnet is a soft iron diaphragm ,d1 held in a frame or mouthpiece ,t4 ,any change of current in the line affects the magnetism of the magnet1 causing it to attract the diaphragm more or less4 ,the magnet and diaphragm really constitute a little electric motor1 the diaphragm vibrating back and forth through an exceedingly short range1 for changes in the magnetic attraction4 ,the principle of the reversibility of the dynamo applies here4 ,if the magnet is subjected to no change in magnetism1 and if the diaphragm is moved or vibrated in front of its poles1 currents will be induced in the wire bobbin which surrounds its end4 ,if two such magnets with bobbins and diaphragms are arranged as shown1 vibrations imparted to one diaphragm will send currents through the line which1 affecting the magnetism of the distant magnet1 will cause its diaphragm to vibrate in exact accordance with the motions of the first or motor diaphragm4 ,in the combination one telephone represents a dynamo1 the other a motor4 ,if the vibrations of the diaphragm are imparted by the voice1 the voice with all its modulations will be reproduced by the telephone at the distant end of the line4 #ebc ,,standard ,,electrical ,,dictionary4 ,fig4 #cbd4 ,,diagram ,,of ,,bell ,,telephones ,,and ,,line ,,with ,,earth ,,connections4 ,fig4 #cbe4 ,,section ,,of ,,bell ,,telephone4 ,the above gives the essential features of the ,bell telephone4 ,in practice the telephone is used only as the receiver4 ,as transmitter a microphone is employed4 ,to give the current a battery1 generally of the open circuit type1 is used1 and the current in the line is an induced or secondary one4 ,the microphone which is talked to1 and which is the seat of the current variations which reproduce original sound1 is termed the transmitter1 the telephone in which the sounds are produced at the distant end of the line is termed the receiver4 ,fig4 #cbe shows the construction of the ,bell telephone in universal use in this country as the receiver4 ,m is a bar magnet1 in a case ,l ,l4 ,b ,b is a bobbin or coil of insulated wire surrounding one end of the magnet4 ,d is the diaphragm of soft iron plate 7ferrotype metal71 and ,e is the mouthpiece4 ,the terminals of the coil ,b ,b connect with the binding screws ,c ,c4 ,the wire in the coil is ,no4 #cf1 ,a4 ,w4 ,g41 and is wound to a resistance of about #hj ohms4 #ebd ,,standard ,,electrical ,,dictionary4 ,as typical transmitter the ,blake instrument may be cited4 ,it is a carbon microphone4 ,it is shown in section in the cut2 a is the mouthpiece and e is a diaphragm of iron plate1 although other substances could be used2 f is a steel spring1 with a platinum contact piece at its end4 ,one end bears against the diaphragm1 the other against a carbon block k4 ,the latter is carried by a brass block p1 and pressure is maintained between these contacts by the spring g and weight of the piece c1 which by gravity tends to press all together4 ,the current passes by way of the spring f1 carbon button k and spring g through the circuit indicated4 ,a battery is in circuit with these parts4 ,if a telephone is also in circuit1 and the transmitter is spoken against1 the diaphragm vibrating affects the resistance of the carbon-platinum contact1 without even breaking the contact1 and the telephone reproduces the sound4 ,the heavy piece of metal ,c acts by its inertia to prevent breaking of the contact4 ,the position of this piece c1 which is carried by the brass plate m1 is adjusted by the screw n4 ,fig4 #cbf4 ,,section ,,of ,,blake ,,transmitter4 ,in practice the transmitter and battery are usually on a local circuit1 which includes the primary of an induction coil4 ,the line and distant receiving telephone are in circuit with the secondary of the induction coil1 without any battery4 ,telephone1 ,bi-4 ,a pair of telephones carried at the ends of a curved bar or spring so that they fit the head of a person using them4 ,one telephone is held against each ear without the use of the hands4 #ebe ,,standard ,,electrical ,,dictionary4 ,telephone1 ,capillary4 ,a telephone utilizing electro-capillarity for the production of telephonic effects4 ,the following describes the invention of ,antoine ,breguet4 ,the point of a glass tube1 drawn out at its lower end to a capillary opening dips vertically into a vessel4 ,this vessel is partly filled with mercury1 over which is a layer of dilute sulphuric acid4 ,the end of the immersed tube dips into the acid1 but does not reach the mercury4 ,one line contact is with mercury in the tube1 the other with the mercury in the vessel4 ,the arrangement of tube and vessel is duplicated1 giving one set for each end of the line4 ,on introducing a battery in the circuit the level of the mercury is affected by electro-capillarity4 ,the tubes are closed by plates or diaphragms at their tops1 so as to enclose a column of air4 ,it is evident that the pressure of this air will depend upon the level of the mercury in the tube1 and this depends on the electro-motive force4 ,on speaking against the diaphragm the sound waves affect the air pressure1 and consequently the level1 enough to cause potential differences which reproduce the sound in the other instrument4 ,fig4 #cbg4 ,,bregurt',s ,,capillary ,,telephone4 ,telephone1 ,carbon4 ,a telephone transmitter based on the use of carbon as a material whose resistance is varied by the degree of pressure brought to bear upon it4 ,undoubtedly the surface contact between the carbon and the other conducting material has much to do with the action4 ,many carbon telephones have been invented4 ,under ,telephone the ,blake transmitter is described1 which is a carbon telephone transmitter4 ,the ,edison carbon transmitter is shown in section in the cut4 ,e is the mouth piece and ,d the diaphragm4 ,i is a carbon disc with adjusting screw ,v4 ,a platinum plate ,b ,b1 with ivory button b1 is attached to the upper surface of the carbon disc4 ,c ,c is an insulating ring4 ,the wire connections shown bring the disc into circuit4 ,it is connected like a ,blake transmitter4 ,it is now but little used4 ,fig4 #cbh4 ,,section ,,of ,,edison ,,carbon ,,transmitter4 #ebf ,,standard ,,electrical ,,dictionary4 ,telephone1 ,chemical4 ,a telephone utilizing chemical or electrolytic action in transmitting or receiving4 ,the electro-motograph is an example of a chemical receiver4 7,see ,electro-motograph47 ,telephone1 ,electrostatic4 ,a telephone utilizing electrostatic disturbances for reproduction of the voice4 ,in the cut ,d and ,c are highly charged electrophori4 ,the diaphragms ,a and ,b when spoken to affect the potential of the electrophorus so as to produce current variations which will reproduce the sound4 ,dolbear and others have invented other forms of transmitters based on electrostatic action4 ,receivers have also been constructed4 ,a simple condenser may be made to reproduce sound by being connected with a powerful telephone current4 ,fig4 #cbi4 ,,diagram ,,of ,,edison',s ,,electrostatic ,,telephone4 ,telephone ,induction ,coil4 ,the induction coil used in telephone circuits for inducing current on the main line4 ,it is simply a small coil wound with two separate circuits of insulated wire4 ,in the ,edison telephone the primary coil1 in circuit with the transmitter1 is of ,no4 #ah to #bd wire and of #c to #d ohms resistance4 ,the secondary in circuit with the line and receiving instrument is of ,no4 #cf wire and of #bej ohms resistance4 ,the ,bell telephone induction coil has its primary of ,no4 #ah to #bd wire wound to a resistance of #a_/b ohm1 and its secondary of ,no4 #cf wire1 and of #hj ohms resistance4 #ebg ,,standard ,,electrical ,,dictionary4 ,telephone1 ,reaction4 ,a form of telephone containing two coils of insulated wire1 one of which is mounted on the disc1 and the other on the magnet pole in the usual way4 ,these coils react upon each other so as to strengthen the effect4 ,telephone1 ,thermo-electric4 ,a telephone transmitter including a thermo-electric battery1 placed in circuit with the line4 ,a plate of vulcanite faces it4 ,when the sound waves strike the vulcanite they move it backward and forward4 ,these movements1 owing to the elasticity of the vulcanite1 produce minute changes of temperature in it1 which affecting the thermo-electric pile produce in the circuit currents1 which passing through a ,bell telephone cause it to speak4 ,this type of instrument has never been adopted in practice4 ,telephote4 ,an apparatus for transmitting pictures electrically1 the properties of selenium being utilized for the purpose4 ,synonym--,pherope4 ,teleseme4 ,an annunciator1 displaying on a dial the object wanted by the person using it4 ,it is employed to transmit messages from rooms in a hotel to the office1 or for similar functions4 ,tele-thermometer4 ,a thermometer with electric attachment for indicating or recording its indications at a distance4 ,tempering1 ,electric4 ,a process of tempering metals by electrically produced heat4 ,the article is made part of an electric circuit4 ,the current passing through it heats it1 thereby tempering it4 ,for wire the process can be made continuous4 ,the wire is fed from one roll to another1 and if required one roll may be immersed in a liquid bath or the wire between the rolls may be led therein4 ,the current is brought to one roll and goes through the wire to the other4 ,as it does this the wire is constantly fed from one roll to another4 ,the bath may be used as described to cool it after the heating4 ,the amount of heating may be regulated by the rate of motion of the wire4 #ebh ,,standard ,,electrical ,,dictionary4 ,ten1 ,powers of4 ,this adjunct to calculations has become almost indispensable in working with units of the ,c4 ,g4 ,s4 system4 ,it consists in using some power of #aj as a multiplier which may be called the factor4 ,the number multiplied may be called the characteristic4 ,the following are the general principles4 ,the power of #aj is shown by an exponent which indicates the number of ciphers in the multiplier4 ,thus #ajb indicates #ajj2 #ajc indicates #a1jjj and so on4 ,the exponent1 if positive1 denotes an integral number1 as shown in the preceding paragraph4 ,the exponent1 if negative1 denotes the reciprocal of the indicated power of #aj4 ,thus #aj-b indicates #a_/ajj2 #aj-c indicates #a_/ajjj and so on4 ,the compound numbers based on these are reduced by multiplication or division to simple expressions4 ,thus3 #c4ad ,x #ajg #c4ad ,x #aj1jjj1jjj #ca1djj1jjj4 #c4ad ,x #aj-g #c4ad_/aj1jjj1jjj or #cad_/ajjjjjjjjj4 ,regard must be paid to the decimal point as is done here4 ,to add two or more expressions in this notation if the exponents of the factors are alike in all respects1 add the characteristics and preserve the same factor4 ,thus3 7#ea,x #ajf7 7#ed ,x #ajf7 #aje ,x #ajf4 7#i4a ,x #aj-i7 7#h4g ,x #aj-i7 #ag4h ,x #aj-i4 ,to subtract one such expression from another1 subtract the characteristics and preserve the same factor4 ,thus3 7#ed ,x #ajf7 - 7#ea ,x #ajf7 #c ,x #ajf4 ,if the factors have different exponents of the same sign the factor or factors of larger exponent must be reduced to the smaller exponent1 by factoring4 ,the characteristic of the expression thus treated is multiplied by the odd factor4 ,this gives a new expression whose characteristic is added to the other1 and the factor of smaller exponent is preserved for both1 ,thus3 7#e ,x #ajg7 7#e ,x#aji7 7#e ,x #ajg7 7#e ,x #ajj ,x #ajg7 #eje ,x #ajg4 ,the same applies to subtraction4 ,thus3 7#e ,x #aji7 - 7#e ,x #ajg7 7#e ,x #ajj ,x #ajg7 - 7#e ,x #ajg7 #die ,x #ajg4 ,if the factors differ in sign1 it is generally best to leave the addition or subtraction to be simply expressed4 ,however1 by following the above rule1 it can be done4 ,thus3 ,add #e ,x #aj-b and #e ,x #ajc4 #e ,x #ajc #e ,x #aje ,x #aj-b 7#e ,x #aje ,x #aj-b7 7#e ,x #aj-b7 #ejjjje ,x #aj-b ,this may be reduced to a fraction #ejjjjj_/ajj #ejjj4je4 ,to multiply add the exponents of the factors1 for the new factor1 and multiply the characteristics for a new characteristic4 ,the exponents must be added algebraically2 that is1 if of different signs the numerically smaller one is subtracted from the other one1 and its sign is given the new exponent4 ,thus2 7#be ,x #ajf7 ,x 7#i ,x #ajh7 #bbe ,x #ajad4 7#bi ,x #aj -#h7 ,x 7#aa ,x #ajg7 #cai ,x #aj-a 7#i ,x #ajh7 ,x 7#ih ,x #ajb7 #hhb ,x #aja #ebi ,,standard ,,electrical ,,dictionary4 ,to divide1 subtract 7algebraically7 the exponent of the divisor from that of the dividend for the exponent of the new factor1 and divide the characteristics one by the other for the new characteristic4 ,algebraic subtraction is effected by changing the sign of the subtrahend1 subtracting the numerically smaller number from the larger1 and giving the result the sign of the larger number4 7,thus to subtract #g from #e proceed thus2 #e - #g -#b47 ,thus2 7#be ,x #ajf7 _/ 7#e ,x #ajh7 #e ,x #aj-b 7#bh ,x #aj-h7 _/ 7#e ,x #ajc7 #e4f ,x #aj-aa ,transcriber's note3 ,i have replaced ordinary exponential notation by the more compact and simpler programming representation4 ,the last two example would be3 #be;,e#f _/ #e;,e#h #e;,e-#b #bh;,e-#h _/ #e;,e#c #e4f;,e-#aa ,tension4 ,electro-motive force or potential difference in a current system is often thus termed4 ,it is to be distinguished from intensity or current strength1 which word it too greatly resembles4 ,tension1 ,electric4 7a7 ,the condition an electrified body is brought into by electrification1 when each molecule repels its neighbor4 ,the condition is described as one of self-repulsion4 7b7 ,the voltage or potential difference of a circuit is also thus termed4 ,terminal4 ,the end of any open electric circuit1 or of any electric apparatus2 as the terminals of a circuit1 dynamo1 or battery4 ,terminal ,pole4 ,in telegraph line construction the last pole of a series2 one beyond which the line is not carried4 ,such pole1 as the pull of the wires is all in one direction1 requires special staying or support4 ,the regular line poles are free from this strain1 as the wire pulls in both directions4 ,tetanus1 ,acoustic4 ,a term in electro-therapeutics4 ,an effect produced on a nerve by very rapidly alternating induced currents4 ,the currents are produced by an induction coil with a vibrator giving a musical note4 ,this is a species of gauge of proper frequency of alternations4 ,theatrophone4 ,an apparatus worked by automatic paying machinery by which a telephone connection is made with a theatre or opera by the deposition of a coin in a slot4 ,therm4 ,a unit of heat4 ,it has been proposed by the ,british ,association and amounts to a redefinition of the smaller calorie4 ,it is the amount of heat required to raise the temperature of one gram of water one degree centigrade1 starting at the temperature of maximum density of water4 #ecj ,,standard ,,electrical ,,dictionary4 ,thermaesthesiometer4 ,an electro-therapeutic instrument for testing the sensitiveness of the surface of the body to changes of temperature4 ,vessels of mercury are provided with thermometers to indicate their temperature4 ,one vessel is surrounded by an electric conductor wound in a number of turns4 ,the temperature is raised by passing a current through this4 ,by successive applications of the vessels to the same spot upon the skin the power of differentiating temperatures is determined4 ,thermo ,call4 7a7 ,an electric alarm or call bell operated by thermo-electric currents4 ,it may serve as a fire alarm or heat indicator1 always bearing in mind the fact that differential heat is the requisite in a thermo-electric couple4 7b7 ,see ,thermo-electric ,call4 ,thermo-chemical ,battery4 ,a voltaic battery in which the electro-motive force is generated by chemical action induced by heat4 ,the chemical used generally is sodium nitrate or potassium nitrate4 ,the positive plate is carbon4 ,on heating the battery the nitrate attacks the carbon1 burning it and produces potential difference4 ,for negative plate some metal unattacked by the nitrate may be employed4 ,fig4 #ccj4 ,,pouillet',s ,,thermo-,,electric ,,battery4 ,thermo-electric ,battery or ,pile4 ,a number of thermo-electric couples q4 v41 connected generally in series4 ,in ,nobili's pile the metals are bismuth and antimony2 paper bands covered with varnish are used to insulate where required4 ,in ,becquerel's pile copper sulphide 7artificial7 and ,german silver1 7#ij copper1 #aj nickel7 are the two elements4 ,the artificial copper sulphide is made into slabs #d inches long1 #c_/d inch wide1 and #a_/b inch thick 7about74 ,water is used to keep one set of junctions cool1 and gas flames to heat the other set4 ,in ,fig4 #cca1 c1 d represent the binding screws4 ,the couples are mounted on a vertical standard1 with adjusting socket and screw ,b1 so that its lower end can be immersed in cold water1 or raised therefrom as desired4 #eca ,,standard ,,electrical ,,dictionary4 ,,fig4 #cca4 ,,becquerel',s ,,thermo-,,electric ,,batteries4 ,fig4 #ccb shows one couple of the battery4 ,s is artificial antimony sulphide2 ,m is ,german silver2 m is a protecting plate of ,german silver to save the sulphide from wasting in the flame4 ,fig4 #ccb4 ,,elements ,,of ,,becquerel',s ,,thermoelectric ,,batteries4 ,clamond's pile has been used in practical work4 ,the negative element is an alloy of antimony1 #b parts1 zinc1 #a part4 ,the positive element is tin plate4 ,mica in some parts1 and a paste of soluble glass and asbestus in other parts are used as insulators4 ,they are built up so as to form a cylinder within which the fire is maintained4 ,the air is relied on to keep the outer junctions cool4 ,the temperature does not exceed #bjj ,c4 7#cib ,f47 ,sixty such elements have an electro-motive force of #cjj volts and an internal resistance of #a4e ohms4 ,such a battery requires the consumption of three cubic feet of gas per hour4 7,see ,currents1 ,thermo-electric4 7 #ecb ,,standard ,,electrical ,,dictionary4 ,thermo-electric ,call4 ,a thermostat arranged to ring a bell or to give some indication when the temperature rises or falls beyond certain points4 ,it may be a compound bar of brass and steel fixed at one end and free for the rest of its length4 ,its end comes between two adjustable contacts4 ,as the temperature rises it bends one way 7away from the brass side7 and1 if hot enough1 touching a contact gives one signal4 ,if the temperature falls it curves the other way1 and if cold enough touches the other contact1 giving another signal4 7,see ,thermostat1 ,electric47 ,thermo-electric ,couple4 ,if two dissimilar conductors form adjacent parts of a closed circuit1 and their junction is at a different temperature than that of the rest of the circuit1 a current will result4 ,such pair of conductors are called a thermo-electric couple4 ,they may be joined in series so as to produce considerable electro-motive force4 7,see ,thermo-electricity and other titles in thermo-electricity47 ,the efficiency of a thermo-electric couple according to the second law of thermo-dynamics is necessarily low--not over #aj per cent4 ,thermo-electric ,diagram4 ,a diagram indicating the change in potential difference for a fixed difference of temperature between different metals at different temperatures4 ,it is laid out with rectangular co-ordinates4 ,on one axis temperatures are laid off1 generally on the axis of abscissas4 ,on the other axis potential differences are marked4 ,different lines are then drawn1 one for each metal1 which show the potential difference1 say for one degree centigrade difference of temperature between their junctions1 produced at the different temperatures marked on the axis of abscissas4 ,fig4 #ccc ,,thermo-,,electric ,,diagram1 ,,giving ,,potential ,,difference ,,in ,c4 ,g4 ,s4 ,,units4 ,thus taking copper and iron we find at the temperature #j ,c4 7#cb ,f47 a difference of one degree ,c4 7#a4h ,f47 in their junctions will produce a potential difference of #ae4ih micro volts1 while at #bgd4e ,c4 7#ebf4a ,f47 the lines cross1 and zero difference of potential is indicated4 ,taking the lead line on the same diagram it crosses the iron line a little above #cej ,c4 7#ffb ,f471 indicating that if one junction is heated slightly above and the other is heated slightly below this temperature no potential difference will be produced4 ,lead and copper lines1 on the other hand1 diverge more and more as the temperature rises4 #ecc ,,standard ,,electrical ,,dictionary4 ,thermo-electric ,inversion4 ,the thermo-electric relations of two conductors vary at different temperatures4 ,sometimes at a definite point they have no electro-motive force and after passing this point the positive plate becomes a negative one and vice versa4 ,this is inversion1 or reversal4 7,see ,thermo-electric ,diagram47 ,synonym-- ,thermo-electric ,reversal4 ,thermo-electricity4 ,electric energy1 electro-motive force or electrification produced from heat energy by direct conversion4 ,it is generally produced in a circuit composed of two electric conductors of unlike material1 which circuit must possess at least two junctions of the unlike substances4 ,by heating one of these to a higher temperature than that of the other1 or by maintaining one junction at a different temperature from that of the other a potential difference is created accompanied by an electric current4 ,in many cases differential application of heat to an identical material will develop potential difference4 ,this effect1 the converse of the ,thomson effect1 is not used to produce currents1 as in a closed circuit the potential differences due to differential heating would neutralize each other4 ,thermo-electric ,junction4 ,a junction between two dissimilar conductors1 which when heated or cooled so as to establish a differential temperature1 as referred to the temperature of the other junction1 produces potential difference and an electric current4 ,thermo-electric ,pile1 ,differential4 ,a thermo-electric pile arranged to have opposite faces subjected to different sources of heat to determine the identity or difference of temperature of the two sources of heat4 ,it corresponds in use to a differential air thermometer4 ,thermo-electric ,power4 ,the coefficient which1 multiplying the difference of temperature of the ends of a thermo-electric couple1 gives the potential difference1 expressed in micro-volts4 ,it has always to be assigned to a mean or average temperature of the junctions1 because the potential difference due to a fixed difference of temperature between two metals varies with the average temperature of the two junctions4 7,see ,thermo-electric ,diagram47 ,for bismuth and antimony at #ai4e ,c4 7#fg4a ,f47 it is #ajc microvolts per degree ,centigrade 7#a4h ,f474 ,this means that if one junction is heated to #ai ,c4 and the other to #bj ,c4 7#ff4b ,f4 and #fh4j ,f47 a potential difference of #ajc micro-volts will be produced4 ,the potential difference is approximately proportional to the difference of temperature of the two junctions if such difference is small4 ,hence for large differences of potential the thermo-electric power coefficient does not apply4 ,as a differential function it is thus deduced by ,sir ,william ,thomson1 for expressing the ,e4 ,m4 ,f4 in a thermo-electric circuit3 ,if a circuit is formed of two metals with the junctions at indefinitely near temperatures1 t and t dt1 and d,e is the ,e4 ,m4 ,f4 of the circuit1 then the differential coefficient d,e_/dt is called the thermo-electric power of the two metals for the temperature t4 #ecd ,,standard ,,electrical ,,dictionary4 ,thermo-electric ,series4 ,the arrangement of possible thermoelectric elements1 q4 v41 in a table in the order of their relative polarity4 ,bismuth and antimony form a couple in which when their junction is heated the bismuth acts as the positive or negatively charged element and antimony as the negative or positively charged4 ,between these two extremes according to ,seebeck the series runs as follows3 ,antimony1 ,silver1 ,copper1 ,arsenic1 ,gold1 ,platinum1 ,iron1 ,molybdenum1 ,palladium1 ,steel1 ,tin1 ,cobalt1 ,cadmium1 ,lead1 ,nickel1 ,tungsten1 ,mercury1 ,bismuth4 ,zinc1 ,manganese1 ,a differential temperature of #a ,c4 7#a4h ,f47 in a bismuth-antimony couple maintains a potential difference of #ajc micro-volts4 ,matthiessen gives a different series2 it is arranged in two columns2 the first column has positive coefficients annexed the second has negative4 ,on subtracting the greater one from the lesser1 which1 if the two elements are in different columns1 of course amounts to adding after changing the negative sign1 the relative potential difference due to the combination is obtained4 - ,bismuth #be ,gas ,coke #j4a ,cobalt #i ,zinc #j4b ,potassium #e4e ,cadmium #j4c ,nickel #e ,strontium #b4j ,sodium #c4 ,arsenic #c4h ,lead #a4jc ,iron #e4b ,tin #a ,red ,phosphorous #i4f ,copper #a ,antimony #i4h ,silver #a ,tellurium #agi4i ,platinum #j4g ,selenium #bij ,thus the relative ,e4 ,m4 ,f4 of a bismuth-nickel couple1 as both are in the column1 would be #be - #e #bj2 that of a cobalt-iron couple1 one being in the column the other in the - column1 would be #i #e4b #ad4b4 ,alloys are not always intermediate to their constituents1 and small amounts of impurities affect the results largely4 ,this may account for the discrepancies of different observers4 ,other compounds could be introduced into the series4 ,artificial silver sulphide has been used by ,becquerel in a thermo-electric battery4 #ece ,,standard ,,electrical ,,dictionary4 ,thermo-electric ,thermometer4 ,a species of differential thermometer4 ,it consists of two thermo-electric junctions connected in opposition with a galvanometer in the circuit4 ,any inequality of temperature in the two ends or junctions produces a current shown by the galvanometer4 ,it may be used to determine the temperature of a distant place1 one of the junctions being located there and the other being under control of the operator4 ,if the latter junction is heated until no current is produced its temperature is evidently equal to that of the distant couple or junction4 ,the heating may be done with hot water or mercury1 or other melted metal4 ,the temperature of the water1 or other substance1 gives the temperature of the distant place4 ,thermolysis4 ,decomposition by heat2 dissociation4 ,all compound bodies are decomposable by heat if it is intense enough4 ,hence at very elevated temperatures there can be no combustion4 ,synonym--,dissociation4 ,thermometer4 ,an instrument for indicating the intensity of heat4 ,three scales of degrees of heat are used in practise1 the ,fahrenheit1 ,ramur1 and ,centigrade1 each of which is described under its own title4 7,see ,zero1 ,thermometric-,zero1 ,absolute47 ,the ordinary thermometer depends on the expansion of mercury2 in some cases alcohol is used4 ,besides these the compound bar principle as used in the thermostat 7see ,thermostat1 ,electric7 is employed4 ,thermometer1 ,electric4 7a7 ,a thermometer whose indications are due to the change of resistance in conductors with change of temperature4 ,two exactly similar resistance coils maybe electrically balanced against each other4 ,on exposing one to a source of heat1 its resistance will change and it will disturb the balance4 ,the balance is restored by heating the other coil in a vessel of water when the temperature of the water gives the temperature of both coils4 ,the coils are enclosed in water-tight metallic cases4 ,synonym--,electric ,resistance ,thermometer4 7b7 ,a differential thermometer may be made by connecting with a pair of conductors1 two thermo-electric couples in opposition to each other1 and including a galvanometer in series4 ,on heating the junction of one couple more than that of the other a current at once goes through the galvanometer4 7c7 7,see ,thermometer1 ,kinnersley's47 ,synonym--,thermo-electrometer4 #ecf ,,standard ,,electrical ,,dictionary4 ,fig4 #ccd4 ,,kinnersley',s ,,thermometer4 ,thermometer1 ,kinnersley's4 ,a thermo-electrometer4 ,a large glass tube is mounted on a standard and communicates with a small tube parallel to it4 ,water is poured in so as to rise in the small tube4 ,two wires terminating in bulbs enter the large tube by its top and bottom4 ,the upper wire can be adjusted by moving up and down through a stuffing box4 ,on discharging a ,leyden jar through the space between the knobs on the two wires the water for a moment rises in the small tube4 ,there is little or no accuracy in the instrument4 ,it is allied to the electric mortar 7see ,mortar1 ,electric7 as a demonstrative apparatus4 ,synonyms--,electric ,thermometer--,thermo-electrometer4 ,thermo-multiplier4 ,a thermo-electric battery including a number of couples4 ,the term is generally applied to a small battery with its similar junctions facing in one direction and used for repeating ,melloni's experiments on radiant energy1 or so-called radiant heat4 #ecg ,,standard ,,electrical ,,dictionary4 ,thermophone4 ,an apparatus for reproducing sounds telephonically by the agency of heat2 a receiving telephone actuated by heat4 ,thus a wire may be attached to the centre of a diaphragm and kept in tension therefrom1 and the transmitting telephone current may be caused to pass through it4 ,the wire changes in temperature and consequently in length with the pulses of current going through it and vibrates the diaphragm1 reproducing the sound4 ,it is to be distinguished from the thermo-electric telephone which involves the action of potential difference produced by thermo-electric action4 ,thermostat1 ,electric4 ,a thermostat or apparatus1 similar to a thermometer in some cases1 for closing an electric circuit when heated4 ,it is used in connection with automatic fire alarms to give warning of fire4 ,for this use a temperature of #eb ,c4 7#abe ,f47 is an approved one for setting one at1 to complete the circuit4 ,it is also applied to regulation of temperature1 as in incubators4 7a7 ,one kind of thermostat consists of a compound bar wound into a spiral and fastened at one end1 to which a terminal of a circuit is connected4 ,the bar may be made of two strips of brass and iron riveted together1 and wound into a spiral4 ,when such a bar is submitted to changes of temperature it bends in different directions1 because brass expands and contracts more under changes of temperature than does iron4 ,a contact point1 to which the other terminal is connected1 is arranged to make contact with the spiral at any desired degree of temperature1 thus closing an electric circuit and ringing a bell1 opening or closing a damper1 or doing anything else to notify an attendant or to directly change the temperature4 ,if the brass forms the outside of the spiral1 increase of temperature makes the bending of the spiral bring the coils still closer4 ,if the brass forms the inside1 increase of temperature makes the spiral tend to become less close4 ,as shown in the cut1 the brass should lie along the inside of the spiral4 ,sometimes a straight compound bar is used1 one of whose ends is fastened and the other is free4 ,as the temperature changes such a bar curves more or less1 its free end moving to and fro4 ,two contact screws are provided1 one on each side of its free end4 ,if the temperature falls it makes contact with one of these2 if the temperature rises1 it makes contact with the other4 ,thus it may close one of two circuits1 one for a fall and the other for a rise in temperature4 ,it is well to introduce a third bar between the brass and iron ones1 made of some material of intermediate coefficient of expansion4 7b7 ,another kind of thermostat comprises a vessel of air or other gas1 which1 expanding by heat1 actuates a piston or other device and closes an electric circuit4 ,synonym--,electro-pneumatic ,thermostat4 7c7 ,another form utilizes the expansion of mercury4 ,the mercury is made part of an open electric circuit4 ,as it expands it comes in contact with the other terminal of the circuit1 thus completing it1 when the current gives an alarm or does as is provided for in the apparatus employed4 ,thermostats may be worked on either open or closed circuits2 normally the circuit may be open as described and may close on rise of temperature1 or it may be normally closed and open as the temperature rises4 ,fig4 #cce4 ,,electric ,,thermostat4 #ech ,,standard ,,electrical ,,dictionary4 ,thomson ,effect4 ,in an unequally heated conductor the differential heating is either increased as in iron1 or diminished as in copper by a current4 ,in lead the phenomenon does not occur4 ,it is termed the ,thomson effect4 ,it is intimately related to the ,peltier effect4 ,in a thermo-electric couple a heated junction is the source of electro-motive force1 if heated more than other parts of the circuit4 ,the current in a copper-iron junction flows from the copper to the iron across the heated junction4 ,a hot section of an iron conductor next to a cold section of the same is a source of thermoelectricity1 in the sense that the hot section is negative to the colder4 ,a current passing from the hot to the cold iron travels against rising potentials1 and cools the iron in the cooler parts4 ,as it passes to the hotter parts it travels against falling potentials and hence heats the iron in these parts4 ,in this way a current intensifies differential heating in an iron conductor4 ,in copper the reverse obtains4 ,in it the thermo-electric relations of hot and cold copper are the reverse of those of iron1 and a current tends to bring all parts of a differentially heated copper conductor to an identical temperature4 ,as a current travels in iron from hot to cold it absorbs heat2 in copper traveling from cold to hot it absorbs heat4 ,the convection of heat by a current of electricity in unequally heated iron is negative1 for it is opposed to that convection of heat which would be brought about by the flow of water through an unequally heated tube4 ,in copper1 on the other hand1 the electric convection of heat is positive4 7,daniell47 ,the above effects of the electric current upon an unequally heated conductor are termed the ,thomson effects4 ,in iron1 at low red heat1 they are reversed and are probably again reversed at higher temperatures4 #eci ,,standard ,,electrical ,,dictionary4 ,three ,wire ,system4 ,a system of distribution of electric current for multiple arc or constant potential service4 ,it is the invention of ,thomas ,a4 ,edison4 ,it includes three main wires which start from the central station or generating plant1 and ramify with corresponding reduction in size1 everywhere through the district or building to be lighted4 ,as ordinarily carried out when dynamos are used1 the dynamos are arranged in groups of two4 ,one lateral lead starts from the negative binding post of one dynamo4 ,the positive terminal of this dynamo connects to the negative of the other4 ,between the two dynamos the central or neutral lead is connected4 ,the other lateral lead starts from the positive binding post of the second dynamo4 ,the lamps or other appliances are calculated for the potential difference of a single dynamo4 ,they are arranged between the neutral wire and the laterals1 giving as even a disposition as possible to the two laterals4 ,fig4 #ccf4 ,,diagram ,,of ,,three ,,wire ,,system ,,showing ,,neutral ,,wire4 ,if evenly arranged and all burning or using current1 no current goes through the neutral wire4 ,if all the lamps situated on one lateral are on open circuit all the current goes through the neutral wire4 ,in other cases the neutral wire receives the excess of current only4 ,the advantages of the system are that it uses smaller wire than the two wire system for lamps of the same voltage4 ,if lamps of double the voltage were used the two wire system would be most economical4 #edj ,,standard ,,electrical ,,dictionary4 ,four wire and five wire systems have been more or less used1 based on identical considerations1 and involving in each case the coupling of three or of four dynamos respectively1 or else employing a dynamo with special armature connections to give the requisite three-fold or four-fold division of total potential4 ,in the five wire system the total voltage is four times that of a single lamp1 the lamps are arranged four in series across the leads and the central wire is the only one that can be considered a neutral wire4 ,when lamps are burning entirely from three side-leads they constitute a sort of three wire system by themselves1 and their central wire may for the time be a neutral wire4 ,in some of the three wire mains1 especially in the larger sizes1 the neutral wire is made of much smaller section than that of a lateral conductor1 because in extensive districts it is practically impossible that the current should be concentrated in the neutral wire4 ,throw4 ,in a galvanometer the instantaneous deflection of the needle when the contact or closing of the circuit is instantaneous1 or when the discharge is completed before the needle begins to move4 ,the throw of the needle is the datum sought when the ballistic galvanometer is used4 ,synonym--,elongation4 ,throw-back ,indicator4 ,a drop annunciator1 whose shutter or drop is electrically replaced4 ,thrust-bearings4 ,bearings to support the end-thrust or push of a shaft4 ,in disc armatures where the field-magnets attract the armatures in the direction of their axis of rotation1 thrust-bearings have to be provided4 ,in ordinary cylinder or drum armatures end-thrust is not applied1 as a little end motion to and fro is considered advantageous as causing more even wear of the commutator surface4 ,thunder4 ,the violent report which1 as we hear it1 succeeds the lightning flash in stormy weather4 ,it is really produced simultaneously with the lightning and is supposed to arise from disturbance of the air by the discharge4 ,the rolling noise has been attributed to successive reflections between clouds and earth1 and to series of discharges reaching the ear from different distances and through air of varying density4 ,the subject is obscure4 ,by timing the interval from lightning flash to the report of the thunder an approximate estimate of the distance of the seat of discharge can be made4 ,the first sound of the thunder should be timed4 ,an almost concurrence of thunder and lightning indicates immediate proximity of the discharge4 ,transcriber's note3 ,the speed of sound at sea level is about #e seconds per mile4 ,ticker4 ,a colloquial name for a stock or market report automatic printing telegraph1 which prints its quotations and messages on a long tape4 #eda ,,standard ,,electrical ,,dictionary4 ,time ,constant4 7a7 ,when current is first turned into a circuit of considerable self-induction it is resisted rather by the inductance than by the resistance4 ,it is governed by the ratio of resistance and self-induction and this factor represents the time which it takes for the current to reach a definite fraction of its final strength4 ,this fraction is 7#b4gahc - #a7_/b4gahc or #j4fc4 #b4gahc is the base of the ,napierian system of logarithms4 ,thus if in any circuit we divide the inductance in henries by the resistance in ohms1 the ratio gives the time-constant of the circuit1 or it expresses the time which it will take for the current to reach #j4fc of its final value4 7b7 ,in a static condenser the time required for the charge to fall to #a_/b4gahcth part of its original value4 ,time ,cut-outs4 ,cut-outs which automatically cut storage batteries out of the charging circuit when they are sufficiently charged4 ,time-fall4 ,in a secondary battery the decrease with use of electromotive force maintained by a primary or secondary battery4 ,as the battery becomes spent its voltage falls4 ,the conditions of the fall are represented by its discharging curve4 7,see ,curve1 ,discharging47 ,time-reaction4 ,a term in electro-therapeutics2 the period of time occupied in the passage of the effects of an electric current from nerve to muscle4 ,time-rise4 ,in a secondary battery the increase of electromotive force produced during the charging process4 ,its rate and conditions are graphically shown in the charging curve4 7,see ,curve1 ,charging47 ,tin4 ,a metal2 one of the elements2 symbol1 ,sn2 atomic weight1 #aag4h2 equivalent1 #eh4i and #bi4e2 valency1 #b and #d2 specific gravity1 #g4c4 ,it is a conductor of electricity4 ,relative resistance1 compressed1 7,silver #a7 #h4ghd ,specific resistance at #j ,c4 7#cb ,f471 #ac4ba microhms4 ,resistance of a wire at #j ,c4 7#cb ,f471 7a7 #a foot long1 weighing #a grain1 #a4chj ohms4 7b7 #a foot long1 #a_/ajjj inch thick1 #gi4dg 7c7 #a meter long1 weighing #a gram1 4#ifcb 7d7 #a meter long1 #a millimeter thick1 4#afhb ,resistance of a #a inch cube at #j ,c4 7#cb ,f471 #e4bjb microhms4 ,percentage of variation in resistance per degree ,c4 7#a4h ,f471 at about #bj ,c4 7#fh ,f471 4#jcfe ,electro-chemical equivalent 7hydrogen 4#jaje71 4#fai mgs4 4#caj #edb ,,standard ,,electrical ,,dictionary4 ,tinnitus1 ,telephone4 ,a nervous affection of the ear1 of the order of professional cramp2 it is attributed to too much use of the telephone4 ,tin ,sounders4 ,a recent addition to the single needle telegraph4 7,see ,telegraph1 ,single ,needle47 ,it consists of small tin plates1 cut and bent1 and so fitted in pairs to the instrument1 that the needle as deflected strikes one or the other on its right and left hand movements4 ,the sounders can be made to give sufficiently distinctive sounds to make sound-reading1 q4 v41 possible4 ,commercial tin plate1 which is really tinned iron1 seems to give the best results4 ,fig4 #ccg4 ,,tin ,,sounders4 ,tissandier's ,solution4 ,a solution for bichromate batteries4 ,it is composed as follows3 ,water1 #ajj parts by weight potassium bichromate1 #af parts #ff sulphuric acid1 #cg parts4 ,tongue of ,polarized ,relay4 ,the ,german silver extension of the vibrating or oscillating member of a polarized relay1 corresponding to the armature of an ordinary relay4 ,tongue of ,polarized ,relay1 ,bias of4 ,in a ,siemens' polarized relay the pole pieces are adjustable so that they may be brought nearer to or withdrawn from the tongue4 ,one of the poles is adjusted so as to be nearer the tongue4 ,this one-sided adjustment is the bias4 ,its effect is that when the relay is unexcited this pole attracts the armature so that it normally is drawn towards it4 ,this ensures the normal contact of the tongue either with the contact point1 or with the insulated stop piece or adjustment screw4 ,without bias the armature remains in contact with or drawn towards whichever pole it was last attracted to4 ,in its usual use a bias is given it4 ,top1 ,magnetic4 ,a toy illustrating magnetic attraction4 ,it consists of a disc or body of lead or other material1 through which a magnetized steel spindle pointed at its lower end is thrust4 ,a number of short pieces of iron wire are used with it4 ,it is spun like an ordinary top upon the point of the spindle and one of the pieces of iron wire is laid by the side of its point4 ,as it turns the magnetic adherence causes the piece of wire to be carried along in one direction by the rotation of the spindle1 until the end is reached1 when it goes over to the other side of the spindle and travels back again4 ,by using bent pieces of wire of various shapes the most curious effects are produced4 ,circles and ,s shaped pieces give good effects4 ,to increase the mysterious effect covered iron wire 7bonnet wire7 may be employed4 ,fig4 #cch4 ,,magnetic ,,top4 #edc ,,standard ,,electrical ,,dictionary4 ,torpedo1 ,electric4 7a7 ,a fish1 the ,raia ,torpedo1 which possesses the power of giving electric shocks4 7,see ,ray1 ,electric47 7b7 ,an instrument of war2 a torpedo whose operations include electrical discharge or other electric function or factor of operation4 ,torpedo1 ,sims-,edison4 ,a torpedo driven by an electric motor1 and also steered by electricity4 ,its motions are all controlled from the shore4 ,the torpedo proper is carried some distance below the surface of the water by a vessel immediately above it1 from which it is suspended by two rigid bars4 ,in the torpedo is a cable reel on which the conducting cable is disposed4 ,an electric motor and controlling gear are also contained within the torpedo4 ,in its front the explosive is placed4 ,it is driven by a screw propeller actuated by the electric motor4 ,as it moves it pays out cable so that it has no cable to draw after it through the water1 the cable lying stationary in the water behind it4 ,this avoids frictional resistance to its motion4 ,the maintenance of the torpedo at a proper depth is one of the advantages of the system4 #edd ,,standard ,,electrical ,,dictionary4 ,torque4 ,a force tending to produce torsion around an axis4 ,an example is the pulling or turning moment of an armature of an electric motor upon its shaft4 ,it is often expressed as pounds of pull excited at the end of a lever arm one foot long4 ,the expression is due to ,prof4 ,james ,thompson1 then of the ,university of ,glasgow4 ,just as the ,newtonian definition of force is that which produces or tends to produce motion 7along a line71 so torque may be defined as that which produces or tends to produce torsion 7around an axis74 ,it is better to use a term which treats this action as a single definite entity than to use terms like 'couple' and 'moment1' which suggest more complex ideas4 7,s4 ,p4 ,thompson47 ,a force1 acting with radius r gives a torque equal to f ,x r 2 f and r may be expressed in any units4 ,s4 ,p4 ,thompson gives the following equivalents 3 ,to reduce dyne-centimeters to gram centimeters1 divide by #iha dyne-centimeters to meter-kilograms divide by #iha;,e#e dyne-centimeter1 to pound-feet divide by #ac4ef;,e#f pound-feet to meter-kilograms divide by #g4bc ,in each of these compound units the first unit is the force and the second unit is the radius or lever arm of the torque4 ,synonyms--,turning ,moment--,moment of ,couple--,axial ,couple--,angular ,force--,axial ,force4 ,torsion ,balance1 ,coulomb's4 ,originally an apparatus in which electrostatic attraction or repulsion is measured against the torsion of a filament1 often of silk-worm cocoon fibre4 ,it consists in one form of a cylindrical glass vessel in which a light shellac needle is suspended horizontally by a fibre4 ,this needle carries at one end a gilded disc or sphere and is suspended by a fine wire1 or filament4 ,a proof plane1 q4 v41 is excited by touching it to the body under trial2 it is then inserted in the case4 ,the disc on the needle is first attracted and then repelled4 ,the position finally taken by the needle is noted4 ,the force of torsion thus produced is determined by twisting the filament by the torsion head on the top of the apparatus so as to move the needle a certain distance towards the proof plane4 ,the more the torsion-head has to be turned to carry the needle through a specified arc the greater is the torsion effected or the greater is the repulsion exerted1 ,the torsional force of a wire is proportional to the angle of torsion2 this gives the basis for the measurement4 ,with magnetic needle it is used to measure magnetic repulsion and attraction4 ,the best material for the filament is quartz1 but the instrument is not very much used4 ,torsion ,galvanometer4 ,a galvanometer in which the torsion required to bring the index back to zero1 when the current tends to displace it1 is made the measure of the current strength or of the electro-motive force4 ,it involves the use of a torsion head1 q4 v41 or its equivalent4 #ede ,,standard ,,electrical ,,dictionary4 ,torsion ,head4 ,the handle and disc from whose undersurface the filament depends to which the needle or magnet is attached4 ,it is turned to measure the torsional effect1 the edge of the disc being marked or graduated so as to give the angle of deflection required to overcome the effect of the torque of the needle4 ,torsion ,suspension4 ,suspension by one or more wires1 fibres1 or ribands1 involving the restitutive force of torsion4 ,thus fibre suspension1 q4 v41 is a variety of torsion suspension4 ,often a single riband of steel stretched horizontally and secured at both ends is used1 the suspended object1 e4 g41 a balance beam1 being attached at its own centre to the centre of the stretched riband4 ,quite sensitive balances are constructed on this principle4 ,it is peculiarly available where an electric current is to be transmitted1 as absolute contact is secured1 as in ,william ,thomson's ampere balances4 ,touch4 ,a term applied to methods of magnetization1 as single touch1 double touch1 or separate touch1 indicating how the poles of the inducing magnet or magnets are applied to the bar to be magnetized4 ,under the titles of ,magnetization the different methods are described4 ,tourmaline4 ,a mineral2 a subsilicate2 characterized by the presence of boric trioxide1 which replaces aluminum oxide4 ,it is notable for possessing pyro-electric properties4 7,see ,pyro-electricity47 ,tower1 ,electric4 ,the tower used in the tower system1 q4 v41 of arc light illumination4 ,tower ,system4 ,in electric lighting the system of lighting extended areas by powerful arc lamps placed on high towers1 generally of iron or steel frame-work4 ,the lights are thus maintained at a high elevation1 giving greater uniformity of illumination than if they were lower1 but at the expense of considerable light which is lost4 ,sometimes wooden masts are employed instead of towers4 ,the principle involved is that the intensity of light at any place given by a source of illumination varies with the square of its distance from the place in question4 ,hence in using strong arc lights it is an object to have the distances of all parts of the area illuminated at as nearly uniform distances from the light as possible4 ,an approximation to uniformity is secured by placing the lamps at a very high elevation4 #edf ,,standard ,,electrical ,,dictionary4 ,transformer4 ,in alternate current lighting the induction coil by which the primary current with high initial electro-motive force is caused to produce a secondary current with low initial electromotive force4 ,a typical transformer consists of a core of thin iron sheets4 ,the primary is of comparatively thin wire and often of ten or more times as many turns as the secondary4 ,the latter is of thicker wire4 ,where the ratio of #aj to #a as regards number of turns in the primary and secondary obtains1 the initial ,e4 ,m4 ,f4 of the secondary is one-tenth that of the primary circuit4 ,the cores are laminated1 as described1 to avoid the formation of ,foucault currents4 ,the counter-electro-motive force of the transformer when the secondary circuit is open1 prevents any but the slightest current from passing through the primary4 ,in proportion as the secondary is closed and its resistance diminished1 as by lighting more lamps in parallel1 the counter-electro-motive force of the transformer falls and more current passes through the primary4 ,fig4 #cci4 ,,ferranti',s ,,transformer4 ,the economy of the apparatus is in the fact that counter-electromotive force reduces current through a conductor without absorbing any energy4 ,a resistance coil cuts down a current1 but absorbs energy equal to the current multiplied by the potential difference between the terminals of the coil4 ,this electric energy is converted into heat energy and is wasted4 ,but the counter-electromotive force of a transformer is exerted to reduce current without production of heat and with little waste of energy4 ,this is one of the advantages of the alternating current system of distribution of electric energy4 ,the object of a transformer being to secure safety to the person or to life by the separation of the high potential primary or street circuit1 and the low potential house circuit1 any contact of the two circuits in the converter is a source of danger4 ,special care should be taken to ensure absence of leakage1 as it is termed4 ,mica or other insulation is sometimes employed to prevent the wires from coming in contact by piercing or sparking with the core and with each other4 #edg ,,standard ,,electrical ,,dictionary4 ,transformer1 ,commuting4 ,a type of continuous current transformer1 resembling a dynamo with armature and field both stationary1 but with revolving commutator1 by which the magnetic polarity of a double wound armature is made to rotate4 ,this secures the desired action1 of a change or lowering of potential4 ,transformer1 ,continuous ,alternating4 ,an apparatus for transforming a continuous into an alternating current or the reverse4 ,the combination of a continuous current dynamo with an alternating current one is sometimes employed4 ,it is a form of motor dynamo4 ,another type is a regular dynamo with ordinary commutator and with1 in addition thereto1 two1 three or four contact rings1 connecting to as many symmetrically disposed points in the winding of the armature4 ,this will give out or receive alternating currents of two1 three or four phases according to the number of collecting rings4 ,one winding serves for both alternating and continuous currents4 ,transformer1 ,continuous ,current4 ,a machine of the dynamo type for changing the potential of a circuit4 ,in one form two armatures are mounted on one shaft in a single field or in separate fields2 one is a motor armature driven by the original current2 the other generates the new current4 ,this is a motor dynamo4 ,in #ahgd ,gramme constructed a machine with ring armature with two windings1 of coarse and fine wire respectively1 and with independent commutators4 ,such dynamo could transform currents up or down4 ,continuous current transformers have attained an efficiency of #hc per cent4 at full load1 and of #ge per cent4 at half load4 ,owing to the balancing of the self-inductions of the two windings these machines do not spark4 ,as the driven and driving parts are contained in one rotating part their friction is very slight4 ,transformer1 ,core4 ,a transformer wound upon an enclosed core1 such as the hedgehog transformer 7see ,transformer1 ,hedgehog71 or common induction coil4 #edh ,,standard ,,electrical ,,dictionary4 ,transformer1 ,hedgehog4 ,an induction coil transformer whose iron core is composed of a bundle of iron wires1 which after the wire windings are in place have their ends spread out to reduce to some extent the reluctance of the circuit1 which at the best is high1 as the air acts as the return circuit4 ,this transformer has a low degree of hysteresis2 and its efficiency for very small loads or for no load is superior to that of the closed magnetic circuit transformer4 ,fig4 #cdj4 ,,swinburne',s ,,hedgehog ,,transformer4 ,transformer1 ,multiple4 ,a transformer connected in parallel with others between the two leads of the primary circuit4 ,the term refers to the connection only and not to any peculiarity of the transformer itself4 ,transformer1 ,oil4 ,a transformer with oil insulation4 ,the advantage of this insulation is that if pierced it at once closes1 so that no permanent injury ensues4 ,it is a self-healing form of insulation4 ,transformer1 ,series4 ,transformers connected in series upon the primary circuits4 ,the term1 like multiple transformers1 only applies to the connection1 not to the transformer4 ,series transformers are but little used4 ,transformer1 ,shell4 ,a transformer with its iron core entirely outside of and enclosing the primary and secondary winding4 ,it may be made by the use of outer iron wire windings as core4 ,transformer1 ,welding4 ,the transformer used for electric welding4 7,see ,welding1 ,electric47 ,it is a transformer with very long primary and exceedingly short and thick secondary4 ,it is used with the alternating current in the primary1 and produces in the secondary circuit which includes the bars to be welded a very low potential difference4 ,owing to the very low resistance of the secondary circuit this low electro-motive force produces a very strong current1 which develops the requisite heat4 ,the same type of transformer is used for brazing and similar purposes4 #edi ,,standard ,,electrical ,,dictionary4 ,transmitter4 ,in general electric phraseology1 any instrument which produces signals to be transmitted through a line or circuit is a transmitter4 ,thus the ,morse key in telegraphy or the ,blake transmitter in telephony are examples of such4 ,transmitter1 ,carbon4 ,a form of microphone used as a telephone transmitter4 7,see ,carbon ,telephone47 ,transposing4 ,a method of laying metallic circuits for telephoning4 ,the wires at short intervals are crossed so that alternate sections lie on opposite sides of each other4 ,it is done to avoid induction4 ,transverse ,electro-motive ,force4 ,electro-motive force in a substance in which electric displacement is taking place1 produced by a magnetic field4 ,it is sometimes assigned as the cause of the ,hall effect1 q4 v4 ,trimmer1 ,brush4 ,a shears for cutting off evenly and squarely the ends of copper dynamo brushes4 ,the brushes when uneven from wear are removed from the brush holders1 and their ends are sheared off in the trimmer4 ,trolley4 ,a grooved metallic pulley or set of pulleys which runs along an active wire of a circuit1 a lead from which trolley goes to earth or connects with another wire1 so that the trolley takes current generally for operating a street car motor placed upon the circuit leading from it2 a rolling contact with an electric lead4 ,trolleys are principally used on electric railroads1 and are now universally of the sub-wire system1 being at the end of a pole which is inclined backward and forced upward by springs1 so as to press the trolley against the bottom of the wire4 ,thus the trolley does not increase the sagging of the wire1 but tends to push it up a little in its passage4 ,trolley1 ,double4 ,a trolley with two rollers or grooved wheels1 placed side by side1 and running on two parallel leads of wire4 ,it is adapted to systems employing through metallic trolley lines with the motors in multiple arc1 connecting or across the two leads4 ,trolley ,section4 ,an unbroken or continuous section of trolley wire4 ,trouv's ,solution4 ,an acid exciting and depolarizing solution for a zinc-carbon battery4 ,its formula is as follows3 ,water1 #hj parts2 pulverized potassium bichromate1 #ab parts2 concentrated sulphuric acid1 #cf parts2 all parts by weight4 ,the pulverized potassium bichromate is added to the water1 and the acid is added slowly with constant stirring4 ,as much as #be parts potassium bichromate may be added to #ajj parts of water4 ,the heating produced by the acid and water dissolves nearly all the potassium salt4 ,use cold4 #eej ,,standard ,,electrical ,,dictionary4 ,true ,contact ,force4 ,a species of electro-motive force whose existence is supposed to be proved by the ,peltier effect4 ,the lowering in temperature of a contact of dissimilar metals is attributed to a force that helps the current on its way if in the direction of thermo-current proper to the junction and opposing it if in the reverse4 ,the true contact force is taken to explain this phenomenon2 thermo-electric force cannot1 as there is no heat or cold applied to the junction4 ,trumpet1 ,electric4 ,an apparatus consisting of a vibrating tongue1 kept in motion by electricity as in the buzzer1 q4 v41 placed in the small end of a trumpet-shaped tube4 ,trunking ,switchboard4 ,a telephone switchboard arranged in sections1 which sections are connected by trunk lines1 through which trunk lines the desired connections are made4 ,trunk ,lines4 ,in telephone distribution systems1 the lines connecting different stations1 or different sections of a switch-board and used by anyone requiring such connections2 one trunk line answers for a number of subscribers4 ,tube1 ,electric4 ,a tube of glass around which is pasted a series of tinfoil circles1 diamonds1 or little squares1 or other form of interrupted conductor4 ,the pieces generally are placed in the line of a spiral4 ,when a static discharge of electricity takes place along the conductor a row of bright sparks is produced at the breaks in the conductor4 ,these by reflection are multiplied apparently1 and a beautiful effect of intersecting or crossing spirals of sparks is presented4 ,the experiment is in line with the luminous pane and lightning jar1 and is used merely as a demonstration1 or lecture experiment4 ,synonym--,luminous ,tube4 ,tubular ,braid4 ,a braid woven of tissue or worsted1 and tubular or hollow4 ,its object is to provide a covering which can be drawn over joints in covered wires4 ,in making the joint the ends of the wires are necessarily bared1 and a short piece of tubular braid is used for covering them4 ,it is drawn by hand over the joint4 ,turns4 ,an expression applied to the convolutions of wire in a solenoid1 electro-magnet1 or other apparatus or construction of that kind4 ,a turn indicates a complete encircling of the core or axis of the object4 ,thus a wire wound five times around a bar gives five turns4 ,while this is its primary meaning the term if compounded may refer to virtual turns4 ,thus an ampere-turn means one ampere passing through one turn4 ,but ten ampere-turns may mean ten amperes passing through ten turns1 five amperes passing through two turns1 and so on4 ,this use is analogous to a dimension of length in a compound word1 as foot-pound4 ,transcriber's note3 ,but ten ampere-turns may mean ten amperes passing through ,,one turn or one ampere through ten turns1 and so on4 ,there may be a number of kinds of turns qualified by descriptive adjectives1 as series-turns1 the turns of wire in a series circuit of a compound dynamo4 ,in the same way there are shunt-turns4 ,if series ampere-turns or shunt ampere-turns are meant the word ampere should be included4 #eea ,,standard ,,electrical ,,dictionary4 ,turns1 ,dead1 of a ,dynamo4 ,the rotations of a dynamo armature while it is building itself up or exciting itself4 ,the expression is a bad one1 as it is likely to be confounded with the dead turns of armature wire4 ,turns1 ,primary ,ampere-4 ,the ampere-turns in a primary circuit of an induction coil or transformer4 ,in an electric welding transformer1 or in the transformer used in the alternating current system1 where efficiency is an important element1 the ampere-turns in primary and secondary for an efficiency of #ajj per cent4 should be equal4 ,in the case of an experimental induction coil other considerations outweigh that of mere efficiency4 ,insulation1 including security from piercing1 and the production of as long a spark as possible1 are1 in these cases1 the controlling consideration4 ,transcriber's note3 ,a #ajj per cent efficient transformer is impossible1 but over #ii per cent is common4 ,at room temperature there is always some lost flux1 eddy currents and resistive losses4 ,turns1 ,secondary ,ampere-4 ,the ampere-turns on the secondary circuit of an induction coil or transformer4 ,these depend on the path provided for the current4 ,if of negligible inductance1 such as a number of incandescent lamps would provide1 the ampere-turns should be equal to those of the primary coil4 7,see ,turns1 ,primary ,ampere47 ,typewriter1 ,electric4 ,a typewriter in which the work of printing or of pressing the type faces against the paper1 or printing ribbon1 is done by electro-magnetic attraction4 ,the keys close electric circuits1 throwing the electro-magnetic action into play4 ,this involves the use of electricity for what is ordinarily only a mechanical process4 ,the strength of the impression1 however1 is independent of the touch of the operator4 ,it has not come into very extensive use4 ,transcriber's note3 ,,ibm introduced widely used electric typewriters in #aice4 ,ultra-gaseous ,matter4 ,gas so rarefied that its molecules do not collide or very rarely do so4 ,experiments of very striking nature have been devised by ,crookes and others to illustrate the peculiar phenomena that this matter presents4 ,the general lines of this work are similar to the methods used in ,geissler tube experiments1 except that the vacua used are very much higher4 ,when the vacuum is increased so that but one-millionth of the original gas is left the radiant state is reached4 ,the molecules in their kinetic movements beat back and forth in straight lines without colliding1 or with very rare collisions4 ,their motions can be guided and rendered visible by electrification4 ,a tube or small glass bulb with platinum electrodes sealed in it1 is exhausted to the requisite degree and is hermetically sealed by melting the glass4 ,the electrodes are connected to the terminals of an induction coil or other source of high tension electrification4 ,the molecules which come in contact with a negatively electrified pole are repelled from it in directions normal to its surface4 ,they produce different phosphorescent or luminous effects in their mutual collisions4 ,thus if they are made to impinge upon glass1 diamond or ruby1 intense phosphorescence is produced4 ,a piece of platinum subjected to molecular bombardment is brought to white heat4 ,a movable body can be made to move under their effects4 ,two streams proceeding from one negative pole repel each other4 ,the stream of molecules can be drawn out of their course by a magnet4 ,the experiments are all done on a small scale in tubes and bulbs1 resembling to a certain extent ,geissler tubes4 ,transcriber's note3 ,these effects are caused by plasma--ionized gas and electrons4 #eeb ,,standard ,,electrical ,,dictionary4 ,unbuilding4 ,the loss of its charge or excitation by a self-exciting dynamo4 ,it is the reverse of building-up4 ,the latter indicates the exciting of the field by the action of the machine itself2 the former the spontaneous loss of charge on open circuit or from other cause4 ,underground ,conductor4 ,an electric conductor insulated and placed under the surface of the earth1 as distinguished from aerial conductors4 ,underground ,electric ,subway4 ,a subway for the enclosing of electric telegraph and other conductors under the surface1 generally in the line of streets1 to do away with telegraph poles and aerial lines of wire4 ,many systems have been devised4 ,the general type includes tubes called ducts in sets1 called conduits1 bedded in concrete or otherwise protected4 ,every two or three hundred feet the sets lead into a cistern-like cavity called a manhole4 ,the insulated wires or cables1 generally sheathed with a lead alloy are introduced into the tubes through the man-holes4 ,a rope is first fed through the tube4 ,to do this short rods which screw together are generally employed4 ,one by one they are introduced1 and each end one is screwed to the series of rods already in the duct4 ,when the end of the duct is reached the rope is fastened to the last rod1 and the rods are then drawn through1 unscrewed one by one and removed1 the rope following them4 ,by means of the rope a windlass or capstan may be applied to draw the cable into the duct4 ,at least at every second man-hole the cables have to be spliced4 ,each cable may contain a large number of conductors of small size for telephoning1 or a smaller number for electric light and power4 ,the tendency is now to separate the different classes of wires in important lines1 placing the heavier wires on one side of the street and the telephone and telegraph wires on the other4 ,this of course necessitates two separate conduits4 ,the advantage of underground distribution affects not only the appearance of streets in doing away with unsightly telegraph poles1 but it also removes an element of danger at fires4 ,aerial wires interfere greatly with the handling of ladders at fires1 and expose the firemen who attempt to cut them to danger to their lives from shock4 #ecc ,,standard ,,electrical ,,dictionary4 ,unidirectional4 adj4 ,having one direction as a unidirectional current or unidirectional leak4 ,the term is descriptive1 and applicable to many cases4 ,uniform4 adj4 ,unvarying2 as a uniform potential difference1 uniform current or conductor of uniform resistance per unit of length4 ,the term is descriptive1 and its application and meaning are obvious4 ,uniform ,field of ,force4 ,a field of evenly distributed force2 one in which the number of lines of force per unit of area of any equipotential surface is the same4 ,unipolar4 adj4 ,strictly speaking this term means having only one pole1 and is applied to magnets1 armatures and the like4 ,in its use a solecism is involved1 for there is no such condition possible as unipolar magnetism or distribution of magnetism4 ,an example of its use is shown in unipolar magnets4 7,see ,magnet1 ,unipolar47 ,unipolar ,armature4 ,an armature of a unipolar dynamo2 an armature whose windings continuously cut the lines of force about the one pole1 and hence whose polarity is unchanged in its rotation4 ,unipolar ,current ,induction4 ,current induction produced by moving a conductor through a magnetic field of force so that it always cuts the lines in similar relation to itself4 ,thus it produces a constant current through its own circuit1 if a closed one1 and no commutator is required4 ,as this case always in practice amounts to the cutting of lines of force in the neighborhood of a single pole the term unipolar is employed to designate the action4 ,the simplest representation of unipolar induction is the rotating of a conductor around the end of a bar magnet1 its axis of rotation corresponding with the axis of the magnet4 ,unipolar ,dynamo4 ,a dynamo in which one part of the conductor slides on or around the magnet1 so as always to cut lines of force near the same pole of the magnet4 ,unit4 ,a directly or indirectly conventional and arbitrary quantity1 in terms of which measurements of things with dimensions expressible in the chosen units are executed4 ,thus for length the c4 g4 s4 unit is the centimeter2 the ,b4 ,e4 unit is the foot4 #eed ,,standard ,,electrical ,,dictionary4 ,unit1 ,absolute4 ,a unit based on the three fundamental units of length1 mass and time4 ,these units are the centimeter1 gram and second4 ,each one in itself may be termed a fundamental absolute unit4 ,the system of such units is termed the centimeter-gram-second system4 ,unit1 ,angle4 ,a factor or datum in angular velocity1 q4 v4 ,it is the angle subtended by a portion of the circumference equal in length to the radius of the circle4 ,it is equal very nearly to #eg4biegh or #eg #ag' #dd4h4 ,unit1 ,b4 ,a4 ,this term1 while logically applicable to any of the ,british ,association units1 is often restricted to the ohm as formerly defined by the ,british ,association1 the ,b4 ,a4 ,unit of ,resistance1 q4 v4 ,unit1 ,fundamental4 ,the three units of length1 mass and time1 the centimeter1 gram and second1 are termed fundamental units4 ,on them is based the absolute system of units1 and on multiples of them the practical system of units4 ,unit ,jar4 ,a ,leyden jar which is used as a unit of measure of charge4 ,it consists of a ,leyden jar about #d inches long and #c_/d inch diameter1 with about #f square inches of its outer and the same of its inner surface coated with tinfoil4 ,it is placed between a source of electricity and a larger jar or battery of jars which is to be charged4 ,the inner coating connects with the machine2 the outer coating with the jars to be charged4 ,short conductors terminating in knobs connect with inner and outer coatings1 and the knobs are adjusted at any desired distance apart4 ,by the charging operation the large jar or battery of jars receives a charge by induction1 and the charge of the small jar is at first equal to this quantity4 ,after a while a spark passes from knob to knob1 discharging the small jar4 ,this indicates the reception by the large jars of the quantity of electricity represented by the charge of the small jar4 ,the charging goes on1 and for every spark approximately the same quantity of electricity is received by the larger jars4 ,the sparking distance m is directly proportional to the quantity of electricity1 and inversely proportional to the area of coated surface1 or is proportional to the potential difference of the two coats4 ,this is only true for short sparking distance1 hence for accuracy the knobs should be adjusted not too far from each other4 #eee ,,standard ,,electrical ,,dictionary4 ,unit of ,supply4 ,a commercial unit for the sale of electric energy1 as defined provisionally by the ,english ,board of ,trade2 #a1jjj amperes flowing for one hour under an ,e4 ,m4 ,f4 of #a volt2 #c1fjj1jjj volt-coulombs1 or #a1jjj watt-hours1 are its equivalent4 ,it is equal to #ajjj_/gdf #a4cd electric horse power4 ,synonym--,board of ,trade ,unit4 ,transcriber's note3 ,now called a kilowatt-hour4 ,units1 ,circular4 ,a system of units of cross-sectional area1 designed especially for use in describing wire conductors4 ,the cross-sectional area of such is universally a circle1 and the areas of two wires of different sizes vary with the square of their radii or diameters4 ,hence if the area of a circle of known diameter is determined it may be used as a unit for the dimensions of other circles4 ,any other circle will have an area proportioned to the area of the unit circle1 as the squares of the diameters are to each other4 ,in practise the commonest circular unit is the circular mil4 ,this is the area of a circle one mil1 #a_/ajjj inch1 in diameter and is equal to 4#jjjjjjghed square inch4 ,a wire two mils in diameter has an area of four circular mils2 one ten mils in diameter has an area of one hundred circular mils4 ,thus if the resistance of a given length of wire #a mil in diameter is stated1 the corresponding resistance of the same length of wire of the same material1 but of other diameter1 is given by dividing the first wire's resistance by the square of the diameter in mils of the wire in question4 ,as it is a basic unit1 most conveniently applied by multiplication1 the smaller units are used2 these are the circular mil1 and circular millimeter4 ,units1 ,derived4 ,units derived by compounding or other processes1 from the three fundamental units4 ,such are the units of area1 volume1 energy and work1 momentum and electric units generally4 ,in some cases the dimensions of the derived unit may reduce to those of a simple unit as inductance reduces to length1 but the unit1 as deduced from the fundamental ones1 is still a derived unit4 ,units1 ,practical4 ,a system of units employed in practical computation4 ,the absolute units1 especially in electricity1 have been found too large or too small1 and the attempt to make them more convenient has resulted in this system4 ,it is based on exactly the same considerations as the absolute system of units1 except that multiples of the original fundamental units of length1 mass1 and time have been taken as the base of the new system4 ,these basic units are multiples of the fundamental units4 ,they are the following3 ,the unit of length is #a;,e#i centimeters2 the unit of mass is #a;,e-#aa gram2 the unit of time remains #a second4 ,while this has conduced to convenience in giving better sized units1 micro- and mega-units and other multiples or fractions have to be used4 ,the following are the principal practical electric units3 ,electrostatic ,electromagnetic ,c4 ,g4 ,s ,units4 ,c4 ,g4 ,s4 ,units4 ,intensity-,ampere equal to #c;,e#i #a;,e-#a ,quantity-,coulomb #c;,e#i #a;,e-#a ,potential-,volt 7#a_/c799 ,e-#b #a;,e#h ,resistance-,ohm 7#a_/i799 ,e-#aa #a;,e#i ,capacity-,farad #i;,e#aa #a;,e-#i #eef ,,standard ,,electrical ,,dictionary4 ,universal ,battery ,system4 ,a term in telegraphy4 ,if several equal and high resistance telegraphic circuits are connected in parallel with each other from terminal to terminal of a battery of comparatively low resistance each circuit will receive the same current1 and of practically the same strength as if only one circuit was connected4 ,this is termed the universal battery system4 ,it is a practical corollary of ,ohm's law4 ,the battery being of very low resistance compared to the lines the joining of several lines in parallel practically diminishes the total resistance of the circuit in proportion to their own number4 ,thus suppose a battery of ten ohms resistance and ten volts ,e4 ,m4 ,f4 is working a single line of one hundred ohms resistance4 ,the total resistance of the circuit is then one hundred and ten ohms4 ,the total current of the circuit1 all of which is received by the one line is #aj_/aaj 4#ji ampere1 or #ij milliamperes4 ,now suppose that a second line of identical resistance is connected to the battery in parallel with the first4 ,this reduces the external resistance to fifty ohms1 giving a total resistance of the circuit of sixty ohms4 ,the total current of the circuit1 all of which is received by the two lines in equal parts1 is #aj_/fj 4#aff amperes4 ,but this is equally divided between two lines1 so that each one receives 4#jhc ampere or #hc milliamperes2 practically the same current as that given by the same battery to the single line4 ,it will be seen that high line resistance and low battery resistance1 relatively speaking1 are required for the system4 ,for this reason the storage battery is particularly available4 ,the rule is that the resistance of the battery shall be less than the combined resistance of all the circuits worked by it4 ,unmarked ,end4 ,the south-seeking pole of a magnet1 so called because the other end1 called the marked end1 is usually marked with a scratch or notch by the maker1 while the south pole is unmarked4 ,v4 7a7 ,symbol for velocity4 7b7 ,symbol or abbreviation for volume4 7c7 ,symbol or abbreviation for volt4 #eeg ,,standard ,,electrical ,,dictionary4 ,v4 ,a4 ,symbol or abbreviation for voltaic alternatives1 q4 v4 ,vacuum4 ,a space destitute of any substance4 ,the great pervading substance is in general sense the atmosphere4 ,it is the gaseous mixture which surrounds and envelopes the earth and its inhabitants4 ,it consists of a simple mixture of oxygen1 #a part1 nitrogen1 #d parts1 with #d to #f volumes of carbonic acid gas in #aj1jjj volumes of air1 or about one cubic inch to one cubic foot4 ,it presses with a force of about #ad4g lbs4 per square inch under the influence of the force of gravity4 ,the term vacuum in practise refers to any space from which air has been removed4 ,it may be produced chemically4 ,air may be displaced by carbonic acid gas and the latter may be absorbed by caustic alkali or other chemical4 ,the air may be expelled and the space may be filled with steam which is condensed to produce the vacuum4 ,of course in all cases the space must be included in an hermetically sealed vessel1 such as the bulb of an incandescent lamp4 ,but the universal method of producing a vacuum is by air pumps4 ,an absolute vacuum means the entire absence of gas or air1 something almost impossible to produce4 ,a high vacuum is sometimes understood to mean one in which the path of the molecules is equal in length to the diameter of the containing vessels1 as in ,crookes' ,radiometer and other apparatus for illustrating the radiant condition of matter4 ,the air left after exhaustion is termed residual air or residual atmosphere4 ,transcriber's note3 ,dry air is about 4#gh nitrogen1 4#ba oxygen1 4#ja argon1 4#jjjch carbon dioxide1 and trace amounts of other gases4 ,argon was suspected by ,henry ,cavendish in #aghe4 ,it was discovered in #ahid by ,lord ,rayleigh and ,sir ,william ,ramsay4 ,vacuum1 ,absolute4 ,a space free of all material substance4 ,it is doubtful whether an absolute vacuum has ever been produced4 ,vacuum1 ,high4 ,an approximate vacuum1 so nearly perfect that the molecules of the residual gas in their kinetic motions rarely collide1 and beat back and forth between the walls of the containing vessel1 or between any solid object contained in the vessel and the walls of the vessel4 ,the gas in such a vacuum is in the radiant or ultra-gaseous state4 7,see ,ultra-gaseous ,matter47 ,vacuum1 ,low4 ,a vacuum inferior to a high vacuum2 a vacuum in which the molecules collide with each other and do not move directly from side to side of the containing vessel4 ,vacuum1 ,partial4 ,a space partially exhausted of air so as to contain less than an equal volume of the surrounding atmosphere4 ,it really should come below a low vacuum1 but is often treated as synonymous therewith4 ,vacuum1 ,torricellian4 ,the vacuum existing above the mercurial column in a barometer tube4 ,the principle of this vacuum is applied in the ,geissler and other air pumps4 7,see ,pump1 ,geissler--,pump1 ,sprengel--,pump1 ,swinburne47 #eeh ,,standard ,,electrical ,,dictionary4 ,valency4 ,the relative power of replacing hydrogen or combining therewith possessed by different elements2 the number of atomic bonds belonging to any element4 ,thus oxygen has a twofold valency1 is bivalent or is a dyad1 and combines with two atoms of hydrogen because the latter has a unitary atomicity1 is monovalent or is a monad4 ,valve1 ,electrically ,controlled4 ,a valve which is moved by or whose movements are regulated by electricity4 ,in the block system of railroad signaling the semaphores are worked by weights and pneumatic cylinders and pistons4 ,the valves for admitting or releasing the compressed air are operated by coil and plunger mechanism4 ,there are many other instances of the control of valves by the electric current4 ,vapor ,globe4 ,a protecting glass globe surrounding an incandescent lamp1 when the lamp is to be used in an atmosphere of explosive vapor1 as in mines or similar places2 or when in a place where it is exposed to dripping water which would break the hot lamp bulb if it fell upon it4 ,variable ,period4 ,the period of adjustment when a current is started through a conductor of some capacity4 ,it is the period of duration of the variable state1 q4 v41 in a conductor4 ,as indicated in the next definition in a cable of high electrostatic capacity a variable period of nearly two minutes may exist4 ,this indicates the retardation in signaling to be anticipated in cables and other lines of high capacity4 ,variable ,state4 ,when an electric circuit is closed the current starts through the conductor with its full strength from the point of closure1 and advances with a species of wave front so that some time elapses before it attains its full strength in the most distant parts of the conductor1 owing to its having to charge the conductor to its full capacity at the given potential4 ,the state of the line while the current thus varies is called the variable state4 ,a long telegraph line when a message is being transmitted may be always in the variable state4 ,the current at the receiving end may never attain its full strength4 ,in the case of such a conductor as the ,atlantic cable1 #ajh seconds would be required for a current to attain #i_/aj of its full strength at the distant end1 and but #a_/e second to attain #a_/ajj of its final value4 ,during the period of increase of current the variable state exists4 ,variation of the ,compass4 ,the declination of the magnetic needle4 7,see ,elements1 ,magnetic47 ,as the declination is subject to daily1 annual and secular variations1 it is unfortunate that this term is synonymous with declination4 ,thus the variation of the compass means its declination1 while there is also the variation of the declination and of other elements4 ,the term variation of the compass is more colloquial than the more definite expression declination1 or magnetic declination4 #eei ,,standard ,,electrical ,,dictionary4 ,variometer4 ,an apparatus used in determining the relative values of the horizontal component of the earth's magnetic field in different places4 ,varley's ,condenser4 ,a static condenser whose conducting surfaces are platinum electrodes immersed in dilute sulphuric acid4 ,when the potential difference is #a_/ejth that of a ,daniell's cell1 two square inches of platinum have a capacity equal to that of an air condenser whose plates have an area of #hj1jjj1jjj square inches1 and separated #a_/hth of an inch from each other4 ,as the ,e4 ,m4 ,f4 increases the capacity also increases4 ,varley's ,resistances4 ,variable resistances formed of discs of carbonized cloth1 q4 v41 piled up1 and pressed together more or less firmly to vary the resistance as desired4 ,varnish4 ,a glossy transparent coating of the nature of paint1 applied as a protective1 or ornamental coating to objects4 ,varnish1 ,electric4 ,alcoholic or etherial varnishes are the best for electrical apparatus4 ,they dry quickly and perfectly1 and tend to form surfaces unfavorable to the hygroscopic collection of water4 ,sealing wax dissolved in alcohol1 or shellac dissolved in the same solvent are used for electrical apparatus1 although the first is rather a lacquer than a varnish4 ,etherial solution of gum-copal is used to agglomerate coils of wire4 ,it is well to bake varnished objects to harden the coating4 ,varnish1 ,red4 ,a solution of sealing wax in #ij per cent4 alcohol4 ,it is best made thin and applied in several coats1 each coat being allowed to dry perfectly before the next is applied4 ,it is often seen on ,leyden jars4 ,it is a protector from surface leakage4 ,vat4 ,a vessel for chemical or other solutions4 ,a depositing vat is one in which a plating solution is worked1 for the deposition of electroplate upon articles immersed in the liquid1 and electrolyzed by an electric current4 ,velocity4 ,the rate of motion of a body4 ,it is usually expressed in distance traversed per second of time4 ,the absolute unit is one centimeter per second or kine4 ,the foot per second is very largely used also4 ,the dimensions of velocity are length 7,l7 divided by time 7,t7 or ,l_/,t4 ,velocity1 ,angular4 ,velocity in a circle defined by the unit angle1 or the angle which subtends a circular arc equal in length to itself4 ,the radius of the circle traversed by the moving body does not enter into this definition1 as the real velocity of the object is not stated4 ,if its angular velocity and the radius of the path it travels are given its actual velocity can be deduced4 #efj ,,standard ,,electrical ,,dictionary4 ,velocity of ,signaling4 ,the speed of transmission of electric signals is affected by the nature of the line1 as regards its static capacity1 and by the delicacy of the receiving instruments1 which may need a more or less strong current to be affected4 ,thus of an original current one per cent4 may suffice to operate a sensitive instrument4 ,this might give almost the velocity of light1 while if the instrument would only respond to the full current nearly two minutes 7see ,variable ,state7 might be required for the production of a signal4 ,velocity ,ratio4 ,a term applied to the ratios existing between the electrostatic and electro-magnetic units4 ,if we take as numerators the dimensions of the different qualities in the electrostatic system1 and their dimensions in the electro-magnetic system as denominators1 the fractions thus obtained reduce to expressions containing only velocity or ,v in some form4 ,thus if we divide the dimensions of the electrostatic quantity by the dimensions of electro-magnetic quantity the quotient is simply ,v or velocity4 ,a like division for potential1 electrostatic and electro-magnetic gives 7#a_/,v71 and so on4 ,the value of the velocity ratio is very nearly #c;,e#aj 7sometimes given as #b4ih;,e#aj7 centimeters per second4 ,this is almost exactly that of light 7#b4iiib;,e#aj centimeters per second47 ,this is one of the proofs of ,clerk ,maxwell's magnetic theory of light4 7,see ,maxwell's ,theory of ,light47 ,transcriber's note3 ,the ,,si metre was defined in #aihc such that the speed of light in a vacuum is exactly #bii1gib1deh metres per second or about #ahf1bhb4cig miles per second4 ,ventilation of ,armature4 ,in a dynamo or motor ventilation of the armature is often provided for by apertures through it in order to prevent heating4 ,this heating is caused by ,foucault currents4 ,by proper disposition of the interior of the armature with properly disposed vanes and orifices an action like that of a fan blower can be produced1 which by creating a current of air cools the machine very efficiently4 ,verticity1 ,poles of4 ,points upon the earth's surface where the horizontal component of magnetic force disappears1 leaving only the vertical component active4 ,the term is derived from the verticity of the dipping needle when over either of them4 #efa ,,standard ,,electrical ,,dictionary4 ,vibration ,period4 ,in electrical resonance the period of a vibration in an electrical resonator4 ,the length of this period indicates the quality of the resonator in responding to electrical oscillations by sympathetic vibration4 ,for conductors of small resistance the period is thus calculated4 ,let ,t be the period of one-half a full vibration2 ,l the absolute coefficient of self-induction expressed in centimeters or in henries ,x #aj-i2 ,c the electrostatic capacity of the terminals1 also expressed in the same unit2 v the velocity of light in centimeters per second4 ,then we have the formula ,t ,,pi 99 ,square,root7 ,l 99 ,c 7 _/ v ,transcriber's note3 ,if the inductance is in henries and the capacitance in farads1 frequency in hertz #a_/7b 99 ,,pi 99 square,root7 ,l 99 ,c 7 7 ,vibration1 ,sympathetic4 ,a vibration in a cord or other body susceptible of elastic vibration produced by the vibrations of exactly the same period in a neighboring vibrating body4 ,thus if two tuning forks are tuned to precisely the same pitch1 and are placed near each other1 if one is sounded it will start the other into vibration by sympathy4 ,in electricity its application is found in electric resonance experiments4 ,the resonator has a definite period of electric resonance1 and is made to give a spark by the exciter of identical period4 ,this is by what may be called electric sympathetic vibration1 and is exactly analogous to the action of the tuning forks upon each other4 ,vibrator1 ,electro-magnetic4 ,the make and break mechanism used on induction coils1 or other similar apparatus in which by alternate attractions by and releases from an electro-magnet an arm or spring is kept in motion4 ,in most cases the work is done by a single magnet1 whose armature is attracted to the magnet1 when the latter is excited1 but against the action of a spring which tends to pull it away from the magnet4 ,in its motions a make and break action is produced1 to give the requisite alternations of attraction and release4 ,two electro-magnets may be connected so as alternately to be excited and keep an arm carrying a mutual armature in vibration1 or the same result may be attained by a polarized relay4 ,the make and break is illustrated under ,bell1 ,electric--,coil1 ,induction-- ,anvil4 ,villari's ,critical ,value4 ,magnetization induced or residual in a wire is diminished on stretching1 provided that the magnetization corresponds to an inducing force above a certain critical value1 known as above2 this being 7,sir ,wm4 ,thomson7 about #bd times the terrestrial intensity4 ,below that critical value tension increases the magnetization of a magnetized wire4 ,the effects of transverse expansive stress are opposed to those of longitudinal stretching4 7,daniell47 ,viole's ,standard of ,illuminating ,power4 ,a standard authorized by the ,international ,congress of #ahha4 ,it is the light given by one square centimeter of platinum1 melted1 but just at the point of solidification4 ,it is equal to #bj ,english standard candles almost exactly4 ,it has not been very widely accepted1 the tendency among photometrists being to adhere to the old standards1 carcel or candle4 ,it is obvious that actual use of the ,viole would be very inconvenient and would involve expensive apparatus1 difficult to work with4 ,synonym--,viole4 #efb ,,standard ,,electrical ,,dictionary4 ,vis ,viva4 ,the kinetic energy of a body in motion2 mechanical energy4 ,vitreous ,electricity4 ,positive electricity2 the electricity produced on the surface of glass by rubbing it with silk and other substances4 7,see ,electrostatic ,series47 ,the term positive electricity should be allowed to supplant it4 ,it is the analogue and opposite of resinous electricity4 ,vitriol1 ,blue4 ,a colloquial or trade name for copper sulphate 7,cu ,,so#d74 ,vitriol1 ,green4 ,a colloquial or trade name for ferrous sulphate 7,fe ,,so#d74 ,vitriol1 ,white4 ,a colloquial or trade name for zinc sulphate 7,zn ,,so#d74 ,volt4 ,the practical unit of electro-motive force or potential difference4 ,it may be referred to various data4 ,an electro-motive force of one volt will cause a current of one ampere to flow through a resistance of one ohm4 ,a condenser of one farad capacity charged with one coulomb will have a rise of potential of one volt4 ,the cutting of #ajj1jjj1jjj lines of force per second by a conductor induces one volt ,e4 ,m4 ,f4 ,a ,daniell's battery gives an ,e4 ,m4 ,f4 of #a4jg volts2 about the most familiar approximate standard that can be cited4 ,it is equal to #a_/cjj absolute electrostatic unit4 ,it is equal to #a;,e#h absolute electro-magnetic units4 ,transcriber's note3 ,the ,,si definition of a volt3 ,the potential difference across a conductor when a current of one ampere dissipates one watt of power4 ,voltage4 ,potential difference or electro-motive force expressed in volts2 as a voltage of #ajj volts4 ,thus voltage may express the electro-motive force absorbed in a conductor1 while electro-motive force is a term generally applied where it is produced1 evolved or present in the object4 ,the term voltage of a lamp expresses simply the volts required1 but does not suggest the possession of electromotive force4 #efc ,,standard ,,electrical ,,dictionary4 ,voltage1 ,terminal4 ,the voltage or potential difference at the terminals of an electric current generator1 such as a dynamo1 as distinguished from the total electro-motive force of the dynamo or generator4 ,in batteries the distinction is not generally made in practice2 the total electro-motive force of the battery is made the basis of calculations4 ,voltaic4 adj4 ,this adjective is used to qualify a great many things appertaining to or connected with current electricity4 ,it is derived from ,volta1 the inventor of the voltaic battery1 and now tends to displace the term galvanic1 formerly in general use4 ,voltaic ,alternatives4 ,a term used in electro-therapeutics or medical electricity to indicate an alternating battery current4 ,synonym--,alternative current4 ,voltaic ,effect4 ,the potential difference developed by contact of different conductors4 ,it is the basis of the contact theory1 q4 v41 of electricity1 although it may be accepted as the expression for a condition of things by those who reject the above theory4 ,this potential difference is slight when the conductors are separated1 but it is calculated that it would be enormous could the metals be so quickly separated as to hold each its own charge4 ,thus if a copper and a zinc plate are assumed to be in contact1 really #a_/bjjjjjjj centimeter or #a_/ejjjjjjj inch apart1 they may be treated as a pair of condenser plates4 ,being so near1 their density of charge1 which is a strongly bound charge1 is enormous4 ,if it were possible to separate them without permitting any discharge1 their potential would rise by the separation1 on the principle of ,epinus' condenser1 q4 v41 to such an extent that they would spark through twenty feet of air4 7,see ,volta's ,fundamental ,experiment47 ,voltaic ,electricity4 ,electricity of low potential difference and large current intensity2 electricity such as produced by a voltaic battery2 current or dynamic electricity as opposed to static electricity4 ,voltameter4 ,in general an apparatus for determining the quantity of electricity passing through a conductor by measuring the electrolytic action it can perform4 ,voltameter1 ,copper4 ,an apparatus which may be of similar construction with the silver voltameter 7see ,voltameter1 ,silver71 but in which a copper anode and a solution of copper sulphate are substituted for the silver anode and silver nitrate solution4 ,one coulomb corresponds to 4#cbi milligram or 4#jjejhd grain of copper deposited4 ,it is not accepted as of as high a standard as the silver voltameter4 ,the electrodes should be placed half an inch from each other4 ,two square plate electrodes may conveniently be used1 and not less than two square inches on each plate should be the area per ampere of current4 #efd ,,standard ,,electrical ,,dictionary4 ,voltameter1 ,differential1 ,siemens'4 ,a volume or gas voltameter with duplicate eudiometers and pairs of electrodes4 ,it is used for determining the resistance of the platinum conductor used in his pyrometer4 ,a current divides between the two voltameters2 in one branch of the circuit the platinum conductor is placed1 in the other a known resistance4 ,the current strength varying inversely with the resistance1 the resistances of the two conductors are inversely proportional to the gas evolved4 ,voltameter1 ,gas4 ,a voltameter whose indications are based on the electrolysis of water1 made an electrolyte by the addition of sulphuric acid4 ,the gases evolved are measured4 ,it may take several forms4 ,in one form it is an apparatus consisting of a single eudiometer or graduated glass tube with upper end closed and its lower end or mouth open1 collecting the mixture of hydrogen and oxygen4 ,in the form shown in the cut three tubes are connected1 the side tubes representing eudiometers4 ,for each side tube there is a platinum electrode4 ,in this apparatus the oxygen and hydrogen are connected in opposite tubes4 ,a is an open tube filled with dilute sulphuric acid4 ,by opening the cocks on ,b and ,c they can both be completely filled with acid4 ,as shown in the cut1 this operation is not yet completed4 ,the hydrogen alone may in this case be measured4 ,the mixed gas voltameter has only one eudiometer4 ,the exact equivalents are only approximately known4 ,the volume of mixed gases per coulomb is given as 4#agch cubic centimeters 7,ayrton72 4#agb cubic centimeters 7,hospitalier72 and other values by other authorities4 ,the hydrogen is equal to #a_/c of the mixed gases almost exactly4 ,synonyms--,volume ,voltameter--,sulphuric ,acid ,voltameter4 ,the gas is measured at #j 7#cb ,f47 and #gf centimeters1 or #cj inches barometer4 ,fig4 #cda4 ,,gas ,,voltameter4 #efe ,,standard ,,electrical ,,dictionary4 ,if the gas is measured in cubic inches1 the temperature in degrees ,f41 and the barometric height in inches1 the following formula may be used for reduction to standard pressure and temperature4 ,it is the volume corresponding to one coulomb4 7 4#jajeh 99 #cj 99 7#dia ,f - #cb7 7 _/ 7h99 #dia7 ,for the metric measurements and degrees ,c4 74#agch 99 #gf 99 7#bgc ,c77 _/ 7h ,x #bgc7 ,voltameter1 ,silver4 ,an apparatus consisting of a platinum vessel containing a solution of silver nitrate into which solution a silver anode dips1 whose end is wrapped in muslin to prevent the detachment of any particles4 ,when a current is passed by connecting one terminal to the dish and the other to the rod1 securing a proper direction of current1 silver will be deposited on the dish and the same amount will be dissolved from the rod4 ,the dish is weighed before and after the test4 ,its increase in weight gives the silver deposited4 ,,fig4 #cdb4 ,,silver ,,voltameter4 ,in the cut ,ag is the silver anode1 ,pt is the platinum dish1 r is the conducting rod1 p is a wooden standard1 ,cu is a copper plate on which the dish rests and which also serves as a conductor and contact surface1 b is a muslin cloth to place over the silver plate to prevent detached particles falling in the dish2 s s' are the binding screws4 ,the weight of silver corresponding to a coulomb is given variously by different authorities4 ,ayrton and ,daniell take #a4aahae milligrams or 4#jagbec grain of metallic silver4 ,other determinations are as follows3 #a4aahc milligrams 7,kohlrausch74 #a4abd 7,merscart74 ,the solution of silver nitrate should be from #ae to #cj per cent4 of strength4 ,the current should not exceed one ampere per six square inches2 or in other words not more than about #c_/ajjj grain of silver should be deposited per second on a square inch area of the dish4 ,the edge of the silver disc or anode should be about equidistant from the side and bottom of the dish4 ,the latter notes are due to ,lord ,rayleigh4 #eff ,,standard ,,electrical ,,dictionary4 ,voltameter1 ,weight4 ,a voltameter in which the amount of decomposition is determined by weighing the products1 or one of the products of the electrolysis4 ,the titles ,voltameter1 ,copper1 and ,voltameter1 ,silver1 may be cited4 ,fig4 #cdc4 ,,weight ,,voltameters4 ,in the cuts are shown examples of weight gas voltameters4 ,these are tubes light enough to be weighed when charged4 ,each contains a decomposition cell ,t1 with its platinum electrodes1 and charged with dilute sulphuric acid1 while t is calcium chloride or other drying agent to collect any water carried off as vapor or as spray by the escaping gases2 c are corks placed in position when the weighing is being executed1 so as to prevent the calcium chloride from absorbing moisture from the air4 ,in use the tubes are weighed4 ,they are then connected to the circuit1 after removal of the corks1 and the decomposition proceeds4 ,after a sufficient time they are removed1 the corks put in place1 and they are weighed again4 ,the loss gives the water decomposed4 ,the water corresponding to one coulomb is 4#jicbf milligram 4#jjadcj grain1 ,ayrton1 4#jib ,hospitalier1 4#jice ,daniell4 #efg ,,standard ,,electrical ,,dictionary4 ,voltametric ,law4 ,the law on which voltameters are based4 ,the amount of chemical decomposition produced by an electric current in a given electrolyte is proportional to the quantity of electricity passed through the solution4 ,fig4 #cdd4 ,,volta',s ,,fundamental ,,experiment4 ,volta's ,fundamental ,experiment4 ,the moistened finger is placed on the upper plate of a condensing or electrophorous electroscope4 ,the other hand holds a plate of zinc z1 soldered to a plate of copper c4 ,the lower plate is touched with the copper4 ,on removing the cover the gold leaves l diverge and with negative electricity4 ,hence zinc is supposed to be positively electrified when in contact with copper4 ,the experiment is used to demonstrate the contact theory of electricity4 #efh ,,standard ,,electrical ,,dictionary4 ,volta's ,law of ,galvanic ,action4 ,the electro-motive force between any two metals in an electro-chemical series 7see ,electro-,chemical ,series7 is equal to the sum of the electro-motive forces between all the intervening metals4 ,volta's ,law of ,thermo-electricity4 ,in a compound circuit1 consisting of a number of different metals1 all points of which are at the same temperature1 there is no current4 ,volt1 ,b4 ,a4 ,the volt based on the ,b4 ,a4 ohm4 ,it is equal to 4#ihhi legal volt4 ,volt1 ,congress4 ,the volt based upon the congress or legal ohm2 the legal volt4 ,volt-coulomb4 ,the unit of electric work2 the watt-second2 it is equivalent to #a4j;,e#g ergs4 4#bdjfh gram degree ,c4 7calorie7 4#gcgccg foot lbs41 4#jjacd horse power seconds4 ,volt ,indicator4 ,a form of easily read voltameter for use in electric light stations and for similar work4 ,volt1 ,legal4 ,the legal volt based upon the legal ohm4 ,it is equal to #a4jjaab ,b4 ,a4 volt4 ,voltmeter4 ,an instrument for determining the potential difference of any two points4 ,in many cases it is a calibrated galvanometer wound with a coil of high resistance4 ,the object to be attained is that it shall receive only an insignificant portion of current and that such portion shall suffice to actuate it4 ,if connected in parallel with any portion of a circuit1 it should not noticeably diminish its resistance4 ,the divisions into which ammeters range themselves answer for voltmeters4 ,in practice the same construction is adopted for both4 ,the different definitions of ammeters in disclosing the general lines of these instruments are in general applicable to voltmeters1 except that the wire winding of the coils must be of thin wire of great length4 ,the definitions of ammeters may be consulted with the above understanding for voltmeters4 ,in the use made of voltmeters there is a distinction from ammeters4 ,an ammeter is a current measurer and all the current measured must be passed through it4 ,but while a voltmeter is in fact a current measurer1 it is so graduated and so used that it gives in its readings the difference of potential existing between two places on a circuit1 and while measuring the current passing through its own coils1 it is by calibration made to give not the current intensity1 but the electro-motive force producing such current4 ,in use it may be connected to two terminals of an open circuit1 when as it only permits an inconsiderable current to pass1 it indicates the potential difference existing between such points on open circuit4 ,or it may be connected to any two parts of a closed circuit4 ,owing to its high resistance1 although it is in parallel with the intervening portion of the circuit1 as it is often connected in practice1 it is without any appreciable effect upon the current4 ,it will then indicate the potential difference existing between the two points4 #efi ,,standard ,,electrical ,,dictionary4 ,voltmeter1 ,battery4 ,a voltmeter for use in running batteries4 ,in one form 7,wirt's7 it is constructed for a low range of voltage1 reading up to two and a half volts and having exactly one ohm resistance1 thus giving the battery some work to do4 ,voltmeter1 ,cardew4 ,a voltmeter in which the current passing through its conductor heats such conductor1 causing it to expand4 ,its expansion is caused to move an index needle4 ,by calibration the movements of the needle are made to correspond to the potential differences producing the actuating currents through it4 ,the magnetic action of the current plays no part in its operation4 ,it is the invention of ,capt4 ,cardew1 ,r4 ,e4 ,the construction of the instrument in one of its most recent forms is shown in the cut4 ,on each side of the drum-like case of the instrument are the binding screws4 ,these connect with the blocks m and n4 ,to these the fine wire conductor is connected and is carried down and up over the two pulleys seen at the lowest extremity1 its centre being attached to c4 ,from c a wire is carried to the drum p1 shown on an enlarged scale on the left of the cut4 ,a second wire from the same drum or pulley connects to the spring ,s4 ,the winding of the two wires is shown in the separate figure of c1 where it is seen that they are screwed fast to the periphery of the little drum1 and are virtually continuations of each other4 ,by the screw ,a the tension of the spring ,s is adjusted4 ,on the shaft of the little drum p is a pinion1 which works into the teeth of the cog-wheel r4 ,the shaft of r is extended through the dial of the instrument1 and carries an index4 ,the dial is marked off for volts2 g g and h h are standards for carrying the pulleys4 #egj ,,standard ,,electrical ,,dictionary4 ,the action of the instrument is as follows4 ,the current passing through the wire heats it4 ,this current by ,ohm's law is proportional to the electro-motive force between the terminals4 ,as it is heated it expands and as it cools contracts1 definite expanding and contracting corresponding to definite potential differences4 ,as the wire expands and contracts the block or pin c moves back and forth1 thus turning the drum p and cogwheel r one way or permitting it to turn the other way under the pull of the spring ,s4 ,fig4 #cde4 ,,cardew ,,voltmeter4 ,in this construction for a given expansion of the wire the piece c only moves one half as much4 ,the advantage of using a wire twice as long as would be required for the same degree of movement were the full expansion utilized is that a very thin wire can be employed4 ,such a wire heats and cools more readily1 and hence the instrument reaches its reading more quickly or is more deadbeat1 if we borrow a phraseology properly applicable only to instruments with oscillating indexes4 ,in the most recent instruments about thirteen feet of wire 4#jjbe inch in diameter1 and made of platinum-silver alloy is used4 #ega ,,standard ,,electrical ,,dictionary4 ,if the potential difference to be measured lies between #cj and #abj volts the wire as described suffices4 ,but to extend the range of the instrument a resistance in series is required4 ,if such resistance is double that of the instrument wire1 and remains double whether the latter is hot or cold the readings on the scale will correspond to exactly twice the number of volts4 ,this is brought about in some instruments by the introduction in series of a duplicate wire1 precisely similar to the other wire1 and like it1 carried around pulleys and kept stretched by a spring4 ,transcriber's note3 ,if the series resistance is twice that of the voltmeter1 the indicated voltage will be ,,one ,,third of the total voltage4 ,thus whatever ratio of resistance exists between the two wires cold1 it is always the same at any temperature1 as they both increase in temperature at exactly the same rate4 ,tubes are provided to enclose the stretched wires and pulleys1 which tubes are blackened4 ,the voltmeter is unaffected by magnetic fields1 and1 as its self-induction is very slight1 it is much used for alternating currents4 ,the tubes containing the wire may be three feet long4 ,its disadvantages are thus summarized by ,ayrton4 ,it absorbs a good deal of energy2 it cannot be constructed for small potential differences1 as the wire cannot be made thicker1 as it would make it more sluggish2 there is vagueness in the readings near the zero point and sometimes inaccuracy in the upper part of the scale4 ,volts1 ,lost4 ,the volts at the terminals of a dynamo at full load fall short of their value on open circuit4 ,the difference of the two values are termed lost volts4 ,voltmeter1 ,electrostatic4 ,a voltmeter based on the lines of the quadrant electrometer4 ,it includes two sets of quadrants1 each oppositely excited by one of the two parts1 whose potential difference is to be determined4 ,they attract each other against a controlling force as of gravity4 ,one form has the two sets poised on horizontal axes1 bringing the parts so that the flat quadrants move in vertical planes4 ,in another form a number of quadrants are used in each set1 the members of the two sets alternating with each other4 ,one set is fixed1 the others move and carry the index4 ,vulcanite4 ,vulcanized india rubber which by high proportion of sulphur and proper vulcanization has been made hard4 ,it is sometimes distinguished from ebonite as being comparatively light in color1 often a dull red1 while ebonite is black4 ,for its electrical properties see ,ebonite4 ,both substances have their defects1 in producing surface leakage4 ,washing with weak ammonia1 or with dilute soda solution1 followed by distilled water1 is recommended for the surface1 if there is any trouble with surface leakage4 ,it may also be rubbed over with melted paraffine wax4 #egb ,,standard ,,electrical ,,dictionary4 ,w4 7a7 ,a symbol or abbreviation for watt4 7b7 ,a symbol or abbreviation for work4 7c7 ,a symbol or abbreviation for weight4 ,wall ,bracket4 ,a telegraph bracket to be attached to the external walls of buildings to which wires are attached as they come from the poles to reach converters1 or for direct introduction into a building4 ,wall ,sockets4 ,sockets for incandescent lamps constructed to be attached to a wall4 ,ward4 ,direction in a straight line2 a term proposed by ,prof4 ,james ,thompson4 ,the words backward and forward indicate its scope4 ,water4 ,a compound whose molecule consists of two atoms of hydrogen and one atom of oxygen2 formula1 ,h#b ,o4 ,its specific gravity is #a1 it being the base of the system of specific gravities of solids and liquids4 ,if pure1 it is almost a non-conductor of electricity4 ,if any impurity is present it still presents an exceedingly high1 almost immeasurable true resistance1 but becomes by the presence of any impurity an electrolyte4 ,water ,equivalent4 ,in a calorimeter of any kind the weight of water which would be raised as much as is the calorimeter with its contents by the addition of any given amount of heat received by the calorimeter4 ,waterproof ,lamp ,globe4 ,an outer globe for incandescent lamps1 to protect them from water4 ,watt4 7a7 ,the practical unit of electric activity1 rate of work1 or rate of energy4 ,it is the rate of energy or of work represented by a current of one ampere urged by one volt electro-motive force2 the volt-ampere4 ,it is the analogue in electricity of the horse power in mechanics2 approximately1 #gdf watts represent one electric horse power4 ,ohm's law1 taken as ,c ,e_/,r1 gives as values for current1 ,c and ,e_/,r1 and for electro- motive force ,c ,r4 ,in these formulas1 ,c represents current strength1 ,r represents resistance and ,e represents electro-motive force4 ,then a watt being the product of electro-motive force by current strength1 we get the following values for rate of electric energy1 of which the watt is the practical unit3 7#a7 ,e#b_/,r -- 7#b7 ,c99,e -- 7#c7 ,c#b 99 ,r4 ,the equivalents of the watt vary a little according to different authorities4 ,ayrton gives the following equivalents3 #dd4be foot pounds per minute--4#gcge foot pounds per second--#a_/gdf horse power4 ,these values are practically accurate4 ,hospitalier gives 4#gcgg foot pounds per second4 ,hering gives 4#gcgcbd foot pounds per second1 and #ajjj_/gdeida horse power4 #egc ,,standard ,,electrical ,,dictionary4 ,it is equal to #a;,e#g ergs per second4 ,synonym--,volt-ampere4 7c7 ,it has been proposed to use the term as the unit of energy1 instead of activity or rate of energy 7,sir ,c4 ,w4 ,siemens1 ,british ,association1 #ahhb72 this use has not been adopted and may be regarded as abandoned4 ,transcriber's note2 ,watt is a unit of ,,power--energy per unit of time4 ,watt-hour4 ,a unit of electric energy or work2 one watt exerted or expended for one hour4 ,it is equivalent to 3 #hff4ddh gram-degrees ,c4 7calories7 #bfed4d foot lbs4 #cfjj watt-seconds or volt-coulombs4 #fj watt-minutes4 ,watt-minute4 ,a unit of electric energy or work2 one watt exerted or expended for one minute4 ,it is equivalent to #ad4ddjh gram-degrees ,c4 7calories71 #dd4bdj foot pounds1 #fj watt seconds or volt-coulombs1 #a_/fj watt hour4 ,watts1 ,apparent4 ,the product in an alternating current dynamo of the virtual amperes by the virtual volts4 ,to give the true watts this product must be multiplied by the cosine of the angle of lead or lag4 7,see ,current1 ,wattless47 ,transcriber's note3 ,this is now called a volt-amp4 ,the usual usage is ,,kva1 or kilovolt-ampere4 ,watt-second4 ,a unit of electric energy or work4 ,one watt exerted or expended for one second4 ,it is equivalent to 4#bdjfh gram degree ,c4 7calorie71 4#jjjiee lb4 degree ,f41 4#gcgccg foot lbs41 4#jjacdjf horse power second 7,english71 4#jjaceib horse power second 7metric74 ,synonym--,volt-coulomb4 ,waves1 ,electro-magnetic4 ,ether waves caused by electromagnetic disturbances affecting the luminiferous ether4 7,see ,discharge1 ,oscillatory--,maxwell's ,theory of ,light--,resonance4 ,electric47 ,transcriber's note3 ,the ,michaelson-,morley experiment 7#ahhg7 had already called ether into question1 but quantum theory and photons are decades in the future4 #egd ,,standard ,,electrical ,,dictionary4 ,weber4 7a47 ,a name suggested by ,clausius and ,siemens to denote a magnet pole of unit strength4 ,this use is abandoned4 7b47 ,it has been used to designate the unit of quantity--the coulomb4 ,this use is abandoned4 7c47 ,it has been used to designate the unit of current strength the ampere4 ,this use is abandoned4 ,transcriber's note3 ,definition 7a7 is now used4 ,one weber of magnetic flux linked to a circuit of one turn produces an electromotive force of #a volt if it is reduced to zero at a uniform rate in #a second4 ,weber-meter4 ,an ampere-meter or ammeter4 ,the term is not used since the term weber1 indicating the ampere or coulomb1 has been abandoned4 ,welding1 ,electric4 ,welding metals by heat produced by electricity4 ,the heat may be produced by a current passing through the point of junction 7,elihu ,thomson7 or by the voltaic arc4 7,benardos ,olzewski47 ,fig4 #cdf4 ,,electric ,,welding ,,induction ,,coil4 ,the current process is carried out by pressing together the objects to be united1 while holding them in conducting clamps4 ,a heavy current is turned on by way of the clamps and rapidly heats the metals at the junction1 which is of course the point of highest resistance4 ,as the metal softens1 it is pressed together1 one of the clamps being mounted with feed motion1 flux is dropped on if necessary1 and the metal pieces unite4 ,the most remarkable results are thus attained2 almost all common metals can be welded1 and different metals can be welded together4 ,tubes and other shapes can also be united4 ,in many cases the weld is the strongest part4 #ege ,,standard ,,electrical ,,dictionary4 ,the alternating current is employed4 ,a special dynamo is sometimes used to produce it4 ,this dynamo has two windings on the armature4 ,one is of fine wire and is in series with the field magnets and excites them4 ,the other is of copper bars1 and connects with the welding apparatus1 giving a current of high intensity but actuated by low potential4 ,where the special dynamo is not used1 an induction coil or transformer is used4 ,the primary includes a large number of convolutions of relatively fine wire2 the secondary may only be one turn of a large copper bar4 ,the cut shows in diagram an electric welding coil4 ,p is the primary coil of a number of turns of wire2 ,s ,s is the secondary1 a single copper bar bent into an almost complete circle4 ,it terminates in clamps ,d ,d for holding the bars to be welded4 ,b ,c1 ,b' ,c are the bars to be welded4 ,they are pressed together by the screw ,j4 ,the large coil ,i of iron wire surrounding the coils represents the iron core4 ,the real apparatus as at present constructed involves many modifications4 ,the diagram only illustrates the principle of the apparatus4 ,in welding by the voltaic arc the place to be heated is made an electrode of an arc by connection with one terminal of an electric circuit4 ,a carbon is connected to the other terminal4 ,an arc is started by touching and withdrawal of the carbon4 ,the heat may be used for welding1 soldering1 brazing1 or even for perforating or dividing metal sheets4 ,welding ,transformer4 ,the induction coil or transformer used in electric welding4 ,for its general principles of construction1 see ,welding1 ,electric4 ,wheatstone's ,bridge4 ,a system of connections applied to parallel circuits1 including resistance coils for the purpose of measuring an unknown resistance4 ,a single current is made to pass from ,a through two parallel connected branches1 joining together again at ,c4 ,a cross connection ,b ,d has a galvanometer or other current indicator in circuit4 ,in any conductor through which a current is passing1 the fall of potential at given points is proportional to the resistance between such points4 ,referring to the diagram a given fall of potential exists between ,a and ,c4 ,the fall between ,a and ,b is to the fall between ,a and ,c as the resistance r between ,a and ,b is to the resistance r r' between ,a and ,c4 ,the same applies to the other branch1 with the substitution of the resistances s and ,s' and the point ,d for r r' and ,b4 ,therefore1 if this proportion holds1 r 3 r' 3 3 s 3 ,s'4 ,no current will go through ,b ,d 1 and the galvanometer will be unaffected4 ,assume s' to be of unknown resistance1 the above proportion will give it1 if r1 r' and s are known1 or if the ratio of r to r' and the absolute value of s is known4 #egf ,,standard ,,electrical ,,dictionary4 ,in use the resistances r1 r'1 and s are made to vary as desired4 ,to measure an unknown resistance it is introduced at ,s'1 and one of the other resistances is varied until the galvanometer is unaffected4 ,then the resistance of ,s' is determined by calculation as just explained4 ,the artificial resistances may be resistance coils1 q4 v41 or it is enough to have one unknown resistance at s4 ,then if the length of wire ,,abc is accurately known1 the point ,b can be shifted along it until the balance is attained4 ,the relative lengths ,a ,b1 and ,b ,c1 will then give the ratio r 3 r' needed for the calculation4 ,this assumes the wire ,,abc to be of absolutely uniform resistance4 ,this is the principle of the meter-bridge described below4 ,the use of coils is the more common method and is carried out by special resistance boxes1 with the connections arranged to carry out the exact principle as explained4 ,the principle of construction and use of a resistance box of the ,wheatstone bridge type1 as shown in the cut1 is described under ,box ,bridge1 q4 v4 ,,fig4 #cdg4 ,,wheatstone ,,bridge ,,connections4 ,,fig4 #cdh4 ,,top ,,of ,,box ,,bridge4 #egg ,,standard ,,electrical ,,dictionary4 ,the next cut shows the sliding form of bridge called the meter bridge1 if the slide wire is a meter long or a half- or a quarter-meter bridge1 etc41 according to the length of this wire4 ,it is described under ,meter ,bridge1 q4 v4 ,many refinements in construction and in proper proportion of resistances for given work apply to these constructions4 ,synonyms--,electric ,balance--,resistance ,bridge--,wheatstone's ,balance4 ,fig4 #cdi4 ,,meter ,,bridge4 ,whirl1 ,electric4 7a7 ,a conductor carrying an electric current is surrounded by circular lines of force1 which are sometimes termed an electric whirl4 7b7 ,the ,electric ,flyer4 7,see ,flyer1 ,electric47 ,wimshurst ,electric ,machine4 ,an influence machine for producing high potential or static electricity4 ,two circular discs of thin glass are mounted on perforated hubs or bosses of wood or ebonite4 ,each hub has a groove turned upon it to receive a cord4 ,each disc is shellacked4 ,they are mounted on a horizontal steel spindle so as to face and to be within one-eighth of an inch of each other4 ,on the outside of each disc sixteen or eighteen sectors of tinfoil or thin metal are cemented4 #egh ,,standard ,,electrical ,,dictionary4 ,two curved brass rods terminating in wire brushes curved into a semi-ellipse just graze the outer surfaces of the plates with their brushes4 ,they lie in imaginary planes1 passing through the axis of the spindle and at right angles from each other4 ,four collecting combs are arranged horizontally on insulating supports to collect electricity from the horizontal diameters of the discs4 ,these lie at an angle of about #de with the other equalizing rods4 ,discharging rods connect with the collecting combs4 ,the principle of the machine is that one set of sector plates act as inductors for the other set4 ,its action is not perfectly understood4 ,it works well in damp weather1 far surpassing other influence machines in this respect4 ,on turning the handle a constant succession or stream of sparks is produced between the terminals of the discharging rods4 ,windage4 ,in a dynamo the real air gap between the armature windings and pole pieces is sometimes thus termed4 ,wind1 ,electric4 ,the rush of air particles from a point connected to a statically charged condenser4 ,winding1 ,compound4 ,a method of winding a generator or motor in which a shunt winding is used for the field magnets and in which also a second winding of the magnet is placed in series with the outer circuit4 7,see ,winding1 ,series--,winding1 ,shunt47 ,fig4 #cej4 ,,characteristic ,,curves ,,of ,,shunt ,,and ,,series ,,winding4 ,the object of compound winding is to make a self-regulating dynamo and this object is partly attained for a constant speed4 ,the characteristic curves of shunt and series winding are of opposite natures4 ,the first increases in electro-motive force for resistance in the outer circuit1 the latter decreases under the same conditions4 ,if the windings are so proportioned that these conditions for each one of the two windings are equal and opposite1 it is evident that the characteristic may be a straight line4 ,this1 however1 it will only be at a single speed of rotation4 #egi ,,standard ,,electrical ,,dictionary4 ,winding1 ,disc4 ,a winding which 7,s4 ,p4 ,thompson7 may be treated as a drum winding extended radially1 the periphery corresponding to the back end of the drum4 ,the magnet poles are generally placed so as to face the side or sides of the disc4 ,winding1 ,lap4 ,a method of winding disc and drum armatures4 ,it consists in lapping back each lead of wire towards the preceding lead upon the commutator end of the armature4 ,thus taking the letter ,u as the diagrammatical representation of a turn of wire in connecting its ends to the commutator bars they are brought towards each other so as to connect with contiguous commutator bars4 ,this carries out the principle of keeping the two members of the ,u moving in regions of opposite polarity of field1 so that the currents induced in them shall have opposite directions1 thus producing a total current in one sense through the bent wire4 ,winding1 ,long ,shunt4 ,a system of compound winding for dynamos and motors4 ,the field is wound in series and1 in addition thereto1 there is a shunt winding connected across from terminal to terminal of the machine1 and which may be regarded either as a shunt to the outer circuit1 or as a shunt to the series-field and armature winding4 7,see ,winding1 ,short ,shunt47 ,synonyms--,series and ,long ,shunt ,winding4 ,winding1 ,multiple4 ,a winding of an electro-magnet1 in which separate coils are wound on the core1 so that one or any number may be used as desired in parallel or in series4 ,for each coil a separate binding post should be provided4 ,winding1 ,multipolar4 ,winding adapted for armatures of multi-polar dynamos or motors4 ,winding1 ,series4 ,a method of winding a generator or motor1 in which one of the commutator-brush connections is connected to the field-magnet winding2 the other end of the magnet winding connects with the outer circuit4 ,the other armature-brush connects with the other terminal of the outer circuit4 ,winding1 ,series and ,separate ,coil4 ,a method of automatic regulation applied to alternating current dynamos4 ,winding1 ,short ,shunt4 ,a method of compound winding for dynamos and motors4 ,the field is wound in series1 and in addition thereto there is a shunt winding connected from brush to brush only1 thus paralleling the armature4 7,see ,winding1 ,long ,shunt47 ,synonyms--,series and ,short ,shunt ,winding4 #ehj ,,standard ,,electrical ,,dictionary4 ,winding1 ,shunt4 ,a method of winding a generator or motor4 ,each commutator-brush has two connections4 ,one set are the terminals of the outer circuit1 the other set are the terminals of the field-magnet windings4 ,in other words1 the field-magnet windings are in shunt or in parallel with the outer circuit4 ,winding1 ,shuttle4 ,a method of dynamo or motor-armature winding4 ,a single groove passes longitudinally around the core and in this the wire is continuously wound4 ,the system is not now used4 ,the old ,siemens' ,h armature illustrates the principle4 ,winding1 ,wave4 ,a method of winding disc and drum armatures4 ,it consists in advancing the commutator ends of the ,u shaped turns progressively1 so that as many commutator bars intervene between any two consecutive commutator connections of the wire as there are leads of wire on the drum between consecutive leads of the wire4 ,this is carried out with due regard to the principle that taking the letter ,u as the diagrammatical representation of a turn of wire1 its two members must move through regions of the field of opposite polarity4 ,wire ,finder4 ,a galvanometer or other instrument used for identifying the ends of a given wire in a cable containing several4 ,work4 ,when a force acts upon a body and the body moves in the direction of the force1 the force does work4 ,hence1 work is the action of a force through space against resistance4 ,it is generally expressed in compound units of length and weight1 as foot-pounds1 meaning a pound raised one foot4 ,work1 ,electric1 ,unit of4 ,the volt-coulomb1 q4 v41 or watt-second1 as it is often termed4 ,working1 ,diode4 ,in multiplex telegraphy the transmission of two messages1 simultaneously1 over one wire4 7,see ,telegraphy1 ,multiple47 ,working1 ,contraplex4 ,a variety of duplex telegraphy in which the messages are sent from opposite ends of the line1 simultaneously1 so as to be transmitted in opposite directions4 7,see ,working1 ,diplex47 ,working1 ,diplex4 ,in duplex telegraphy the sending of two independent messages from the same end of the line in the same direction4 #eha ,,standard ,,electrical ,,dictionary4 ,working1 ,double ,curb4 ,a method of working telegraph lines4 ,when a signal is sent the line is charged4 ,this has to be got rid of1 and is an element of retardation4 ,in double curb working it is disposed of by sending a momentary current first in the reverse1 and then in the same1 and finally in the reverse direction4 ,this is found to reduce the charge to a very low point4 ,working1 ,hexode4 ,in multiplex telegraphy the transmission of six messages simultaneously over one wire4 7,see ,telegraphy1 ,multiplex47 ,working1 ,pentode4 ,in multiplex telegraphy the transmission of five messages simultaneously over one wire4 7,see ,telegraphy1 ,multiplex47 ,working1 ,reverse ,current4 ,a method of telegraphy1 in which the currents are reversed or alternated in direction4 ,working1 ,single ,curb4 ,a simpler form of telegraph signaling than double curb working4 ,it consists in sending a reverse current through the line for each signal by reversing the battery connection4 ,working1 ,tetrode4 ,in multiplex telegraphy the transmission of four messages simultaneously over the same line4 7,see ,telegraphy1 ,multiplex47 ,working1 ,triode4 ,in multiplex telegraphy the transmission of three messages simultaneously over the same wire4 7,see ,telegraphy1 ,multiplex47 ,work1 ,unit of4 ,the erg1 q4 v4 ,it is the same as the unit of energy1 of which work is the corelative1 being equal and opposite to the energy expended in doing it4 ,there are many other engineering units of work1 as the foot-pound and foot-ton4 ,yoke4 ,in an electro-magnet1 the piece of iron which connects the ends furthest from the poles of the two portions of the core on which the wire is wound4 ,zamboni's ,dry ,pile4 ,a voltaic pile or battery4 ,it is made of discs of paper1 silvered or tinned on one side and sprinkled on the other with binoxide of manganese4 ,sometimes as many as #b1jjj of such couples are piled up in a glass tube and pressed together with two rods which form the terminals4 ,they maintain a high potential difference1 but having very high resistance and slight polarization capacity1 give exceedingly small quantities4 ,zero4 7a7 ,the origin of any scale of measurement4 7b7 ,an infinitely small quantity or measurement4 #ehb ,,standard ,,electrical ,,dictionary4 ,zero1 ,absolute4 ,from several considerations it is believed that at a certain temperature the molecules of all bodies would touch each other1 their kinetic motion would cease1 and there would be no heat4 ,this temperature is the absolute zero4 ,it is put at -#bgc ,c4 7-#dei ,f47 ,transcriber's note2 ,the modern value is #j ,kelvin1 -#bgc4ae ,c1 or -#dei4fg ,f4 ,the lowest reported temperature observed is #a;,e-#aj ,k4 ,zero1 ,potential4 ,conventionally1 the potential of the earth4 ,true zero potential could only exist in the surface of a body infinitely distant from other electrified bodies4 ,zero1 ,thermometric4 ,there are three thermometric zeros4 ,in the ,raumur and centigrade scales1 it is at the temperature of melting ice2 in the ,fahrenheit scale1 it is #cb ,f4 below that temperature1 or corresponds to -#ag4gh ,c4 ,the third is the absolute zero4 7,see ,zero1 ,absolute47 ,zinc4 ,a metal2 one of the elements2 atomic weight1 #fe4a2 specific gravity1 #f4h to #g4b4 microhms4 ,resistance at #j ,c4 7#cb ,f471 per centimeter cube1 #e4fbf ,resistance at #j ,c4 7#cb ,f471 per inch cube1 #b4bae ,relative resistance 7silver #a71 #c4gda ohms4 ,resistance of a wire1 #a foot long1 weighing #a grain1 4#egff 7a7 #a foot long1 #a millimeter diameter1 #cc4he 7b7 #a meter long1 weighing #a gram1 4#djbc 7c7 #a meter long1 #a millimeter diameter1 4#jgafc ,zinc is principally used in electrical work as the positive plate in voltaic batteries4 ,zincode4 ,the terminal connecting with the zinc plate1 or its equivalent in an electric circuit2 the negative electrode2 the kathode4 ,a term now little used4 ,zinc ,sender4 ,an apparatus used in telegraphy for sending a momentary reverse current into the line after each signal1 thus counteracting retardation4 ,zone1 ,peripolar4 ,in medical electricity1 the region surrounding the polar zone1 q4 v4 ,zone1 ,polar4 ,in medical electricity1 the region surrounding the electrode applied to the human body4 #ehc-fbd ,,index4 ,page ,a #g ,absolute #g ,absolute ,calibration #ig ,absolute ,electric ,potential #dbi ,absolute ,electrometer #bbb ,absolute ,galvanometer #bff ,absolute ,measurement #h ,absolute ,potential #dbh ,absolute ,temperature #h ,absolute ,unit #eed ,absolute ,unit ,resistance1 ,weber's #dfh ,absolute ,vacuum #eeg ,absolute ,zero #eha ,abscissa #g ,abscissas1 ,axis of #ed ,absorption1 ,electric #h ,a4 ,c4 ,c4 #h ,acceleration #h ,accumulator #h ,accumulator1 ,electrostatic #h ,accumulator1 ,water ,dropping #i ,acetic ,acid ,battery #eh ,acheson ,effect #bjh ,acid1 ,carbonic #ajh ,acid1 ,chromic1 ,battery #fa ,acid1 ,hydrochloric1 ,battery #ff ,acid1 ,spent #dia ,acid1 ,sulphuric #dig ,acidometer #aj ,acierage #did ,aclinic ,line #aj ,acoustic ,telegraphy #aj ,acoutemeter #aj1 #ec ,action1 ,electrophoric #bcj ,action1 ,local #cca ,action1 ,magne-crystallic #cce ,action1 ,refreshing #ded ,action1 ,secondary #dgg ,actinic ,photometer #daa ,actinic ,rays4 #aa ,actinism #aa ,actinometer1 ,electric #aa ,active ,electric ,circuit1 #abc ,activity #aa ,actual ,horse ,power #bij ,adapter #aa ,a4 ,d4 ,c41 #aa ,adherence1 ,electro-magnetic #aa ,adherence1 ,magnetic #cch ,adjuster1 ,cord #aeb ,adjustment of ,brushes #ij ,admiralty ,rules of ,heating #ab ,a,eolotropic #cd ,aerial ,cable #ie ,aerial ,conductor #ab ,affinity #ab ,affinity1 ,molecular #chj ,after ,current14 #aei ,agglomerate ,leclanch ,battery #ff ,agir ,motor #ac ,agone #ac ,agonic ,line1 #ac ,air #ac ,air ,blast #ac ,air ,condenser #ad ,air ,field #beb ,air ,gaps #ae ,air ,line ,wire #ae ,air ,pump1 ,heated #ae ,air ,pump1 ,mercurial #af ,air ,pumps1 ,short ,fall #af ,alarm1 ,burglar #af ,alarm1 ,electric #ag ,alarm1 ,fire1 ,electric ,automatic #beg ,alarm1 ,fire and ,heat #ag ,alarm1 ,overflow #ah ,alarm1 ,water ,level #ah ,alcohol1 ,electric ,rectification of #ah ,alignment1 #ah ,allotropy #ah ,alloy #ah ,alloy1 ,platinum #dai ,alloy1 ,platinum-,silver #dai ,alloys1 ,paillard #djj ,alphabet1 ,telegraphic #ai ,alternating #bc ,alternating ,current #aei ,alternating ,current ,arc #bc ,alternating ,current ,dynamo #aic ,alternating ,current ,generator or ,dynamo #bd ,alternating ,current ,meter #cgc ,alternating ,current ,system #bc ,alternating ,field #beb ,alternative ,current #efc ,alternative ,path #bd ,alternatives1 ,voltaic #efc ,alternator #bd ,alternator1 ,constant ,current #bd ,alternator1 ,dead ,point of an #agg ,alternation #bc ,alternation1 ,complete #bc ,alternation1 ,cycle of #age ,alum ,battery #eh ,aluminum #bd ,aluminum ,battery #eh ,amalgam #bd ,amalgamation #be ,amber #be ,american ,twist ,joint #cji ,ammeter #bf ,ammeter1 ,ayrton #bf ,ammeter1 ,commutator #bf ,ammeter1 ,cunynghame's #bf ,ammeter1 ,eccentric ,iron ,disc #bg ,ammeter1 ,electro-magnetic #bg ,ammeter1 ,gravity #bg ,ammeter1 ,magnetic ,vane #bg ,ammeter1 ,magnifying ,spring #bh ,ammeter1 ,permanent ,magnet #bh ,ammeter1 ,reducteur for #dec ,ammeter1 ,solenoid #bh ,ammeter1 ,spring #bh ,ammeter1 ,steel ,yard #bh ,ammunition ,hoist1 ,electric #bi ,amperage #bi ,ampere #bi ,ampere- and ,volt-meter ,galvanometer #bgd ,ampere ,arc #cj ,ampere ,balance #ef ,ampere ,currents #cj ,ampere ,feet #cj ,ampere-hour #cj ,amperes1 ,lost #cj ,ampre's ,memoria ,technica #cj ,ampere ,meters #bf1 #cj ,ampere ,meter1 ,balance #cia ,ampere ,meter1 ,neutral ,wire #cia ,ampere-minute #cj ,ampere ,ring #cj ,ampere-second #cj ,ampere's ,theory of ,magnetism #ced ,ampere-turns #ca ,ampere-turns1 ,primary #ca ,ampere-turns1 ,secondary #ca1 #eea ,ampere ,windings #ca ,amprian ,currents #afe ,amplitude of ,waves #ca ,analogous ,pole #ca1 #dbe ,analysis #ca ,analysis1 ,electric #cb ,analysis1 ,electrolytic #bad ,analyzer1 ,electric #cb ,anelectrics #cb ,anelectrotonus #cb ,angle of ,declination #cb1 #agg ,angle of the ,polar ,span #cb ,angle of ,inclination or ,dip #cc ,angle of ,lag #cc-cah ,angle of ,lead #cc ,angle of ,maximum ,sensitiveness #dgi ,angle of ,polar ,span #dbc ,angle1 ,polar #dbc ,angle1 ,unit #eed ,angular ,currents #afe ,angular ,currents1 ,laws of #afe ,angular ,force #edd ,angular ,velocity #cb1 #eei ,animal ,electricity #cc ,animal ,system1 ,electric ,excitability of #bdg ,anion #cc ,anisotropic #cd ,annealing1 ,electric #cd ,annular ,electro-magnet #baf ,annunciator #cd ,annunciator ,clock #ce ,annunciator ,clock1 ,electric #abg ,annunciator ,drop #ce ,annunciator1 ,gravity ,drop #ce ,annunciator1 ,needle #ce ,annunciator1 ,swinging or ,pendulum #ce ,anodal ,diffusion #ce ,anode #cf ,anodic ,closure ,contraction #cf ,anodic ,duration ,contraction #cf ,anodic ,opening ,contraction #cf ,anodic ,reactions #cf ,anomalous ,magnet #cce ,anti-induction ,conductor #cf1 #ade ,anti-magnetic ,shield #cg ,antilogous ,pole1 #dbe ,antimony #cg ,anvil #cg ,a4 ,o4 ,c4 #ch ,aperiodic #ch ,aperiodic ,galvanometer #bff ,apparent ,coefficient of ,magnetic ,induction #cdf ,apparent ,resistance #big1 #dfb ,apparent ,watts #egc ,arago's ,disc #hh ,arc #ci ,arc1 ,ampere #cj ,arc1 ,compound4 #ci ,arc1 ,electric ,blow-pipe #hd ,arc1 ,metallic #ci ,arc1 ,micrometer #ci1 #cgf ,arc1 ,multiple #chg ,arc1 ,simple #ci ,arc1 ,voltaic #ci ,arc ,box1 ,multiple #chg ,arc ,lamp #cai ,arc ,lamp1 ,differential #cbj ,arc ,lamp1 ,double ,carbon #aia ,areometer #da ,areometer1 ,bead #da ,argyrometry #da ,arm #da ,armature #da ,armature1 ,bar #db ,armature1 ,bipolar #db ,armature ,bore #db ,armature ,chamber #db ,armature1 ,closed ,coil #dc ,armature ,coil1 or ,coils #dc ,armature ,conductors1 ,lamination of #cai ,armature ,core #dc ,armature1 ,cylinder #dc ,armature1 ,cylindrical #de ,armature1 ,disc #dc ,armature1 ,drum #de ,armature ,factor #de ,armature1 ,flat ,ring #de ,armature1 ,girder #di ,armature1 ,h #di ,armature1 ,hinged #de ,armature1 ,hole #de ,armature1 ,intensity #de ,armature ,interference #de ,armature1 ,load of #df ,armature1 ,multipolar #df ,armature1 ,neutral #df ,armature1 ,neutral ,relay #df1 #cij ,armature1 ,non-polarized #df ,armature of ,influence ,machine #df ,armature of ,leyden ,jar or ,static ,condenser #df ,armature1 ,open ,coil #df ,armature1 ,perforated #de ,armature1 ,pivoted #dg ,armature ,pockets #dg ,armature1 ,polarized #dg ,armature1 ,pole #dg ,armature1 ,quantity #dg ,armature1 ,radial #dg ,armature ,reactions #da ,armature1 ,revolving1 ,page's #dg ,armature1 ,ring #dh ,armature1 ,rolling #di ,armatures1 ,gyrostatic ,action of #bhh ,armature1 ,shuttle #di ,armature1 ,siemens' ,old #di ,armature1 ,spherical #di ,armature1 ,stranded ,conductor #di ,armature1 ,unipolar #ej1 #eec ,armature1 ,ventilation of #efj ,armor of ,cable #ej ,arm1 ,rheostat #dgb ,arms1 ,proportionate #dcf ,arms1 ,ratio #dcg ,arms1 ,rocker #ej-dgd ,arrester1 ,lightning #cbh ,arrester1 ,lightning1 ,counter-electro-motive ,force #cbi ,arrester1 ,lightning1 ,plates #cbi ,arrester1 ,lightning1 ,vacuum4 #cbi ,arrester ,plate #dag ,arrester1 ,spark #dhi ,arrival ,curve #afh ,articulate ,speech #ej ,artificial ,carbon #ajf ,artificial ,magnet #cce ,ascending ,lightning #ccj ,assymmetrical ,resistance #dfb ,astatic #ej ,astatic ,circuit #ab ,astatic ,couple #aeg ,astatic ,galvanometer #bff ,astatic ,needle #ej ,astronomical ,meridian1 #cgb ,asymptote #ea ,atmosphere #ea ,atmosphere1 ,residual #ea1 #dfj ,atmospheric ,electricity #ea ,atom #eb ,atomic ,attraction #eb ,atomic ,current #afj ,atomic ,energy #bch ,atomic ,heat #eb-bhe ,atomic ,weight #ec ,atomicity #eb ,attracted ,disc ,electrometer #bbc ,attraction #ec ,attraction1 ,atomic #eb ,attraction1 ,magnetic #cch ,attraction1 ,molar #chj ,attraction1 ,molecular #chj ,attraction and ,repulsion1 ,electro-dynamic #baa ,attraction and ,repulsion1 ,electro-magnetic #bag ,attraction and ,repulsion1 ,electro-static #bcd ,attraction and ,repulsion1 ,electro-static1 ,coulomb's ,law of #aee ,audiometer #ec ,aura1 ,electrical #ec ,aurora #ec ,austral ,pole #ed ,autographic ,telegraph #eaj ,automatic ,circuit ,breaker #aba ,automatic ,cut ,out #age1 #dge ,automatic ,drop #aib ,automatic ,electric ,bell #gh ,automatic ,electric ,fire ,alarm #beg ,automatic ,switch #ejj ,automatic ,telegraph #ejd ,a4 ,w4 ,g41 #ed ,axial ,couple #ead ,axial ,force #edd ,axial ,magnet #ccf ,axis1 ,electric #ed ,axis1 ,magnetic #cch ,axis of ,abscissas #ed ,axis of ,ordinates #ed1 #cig ,axis of ,x #ed ,axis of ,y #ed1 #cig ,ayrton's ,ammeter #bf ,azimuth #ed ,azimuth ,circle #ed ,azimuth ,compass #ada ,azimuth1 ,magnetic #cch ,b #ee ,b4 ,a4 #ee ,back ,electro-motive ,force of ,polarization #aef ,back ,induction #ee ,back ,shock or ,stroke of ,lightning #ee ,back ,stroke #ee ,bagration ,battery #ei ,balance #ee ,balance1 ,ampere #ef ,balance ,ampere ,meter #cia ,balance1 ,electric #egg ,balance1 ,inductance #bic ,balance1 ,plating #dag ,balance1 ,slide #cgd ,balance1 ,thermic #he ,balance1 ,torsion1 ,coulomb's #edd ,balance1 ,wheatstone's #egg ,balata #ef ,ballistic ,galvanometer #efg ,balloon ,battery #ei ,b4 and ,s4 ,w4 ,g4 #ef ,banked ,battery #ei ,bank of ,lamps #cbc ,b4 ,a4 ,ohm #cid ,barad #ef ,bar1 ,armature #db ,bar1 ,bus #id ,bar ,electro-magnet #bag ,bar ,magnet #ccf ,barometer #ef ,bar1 ,omnibus #id ,bar ,photometer #daa ,bars1 ,commutator #ef1 #adj ,bath #eg ,bath1 ,bipolar ,electric #eg ,bath1 ,copper #aeb ,bath1 ,copper ,stripping #aeb ,bath1 ,electric ,head #bhd ,bath1 ,electric ,shower #eg ,bath1 ,gold #bgi ,bath1 ,gold ,stripping #bgi ,bath1 ,multipolar ,electric #eg ,bath1 ,nickel #cia ,bath1 ,plating #dah ,baths1 ,electro-medical #bbb ,bath1 ,silver #dhd ,bath1 ,silver ,stripping #dhd ,bath1 ,stripping #eg ,bath1 ,unipolar ,electric #eg ,batten #eg-eh ,battery1 ,acetic ,acid #eh ,battery1 ,alum #eh ,battery1 ,aluminum #eh ,battery1 ,bagration #ei ,battery1 ,balloon #ei ,battery1 ,banked #ei ,battery1 ,bichromate #ei ,battery1 ,bunsen #ei ,battery1 ,cadmium #fj ,battery1 ,callan #fj ,battery1 ,camacho's #fj ,battery1 ,carr's #fj ,battery1 ,cautery #fa ,battery ,cell1 ,element of a #bcg ,battery1 ,chloric ,acid #fa ,battery1 ,chloride of ,lime #fa ,battery1 ,chromic ,acid #fa ,battery1 ,closed ,circuit #fa ,battery1 ,column #fa ,battery1 d',arsonval's #fb ,battery1 de la ,rue 4#fb ,battery1 de la ,rive's ,floating #agi ,battery1 ,dry #fc ,battery1 ,elements of #fc ,battery1 ,faradic #fc ,battery1 ,ferric ,chloride #fc ,battery1 ,fuller's #fc ,battery1 ,gas #fc ,battery1 ,gas1 ,grove's #bha ,battery ,gauge #fd ,battery1 ,gravity #fd ,battery1 ,grenet #fe ,battery1 ,grove's #fe ,battery1 ,hydrochloric ,acid #ff ,battery1 ,lalande ,chaperon #fi ,battery1 ,lalande-,edison #fi ,battery1 ,lead ,chloride #ff ,battery1 ,lead ,sulphate #ff ,battery1 ,leclanch #ff ,battery1 ,leclanch ,agglomerate #ff ,battery1 ,local #ff1 #hca ,battery1 ,magnetic #cch ,battery1 ,main #ff ,battery1 ,mari ,davy's #fg ,battery1 ,maynooth's #fg ,battery1 ,medical #fg ,battery1 ,meidinger's #fh ,battery1 ,mercury ,bichromate #fc ,battery ,mud #fh ,battery1 ,multiple ,connected #fh ,battery1 ,niaudet's #fa ,battery1 ,nitric ,acid #fh ,battery of ,dynamos #f,s ,battery of ,leyden ,jars1 #fh ,battery1 ,open ,circuit #fh ,battery or ,pile1 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