,illustration ,,scientific ,,american ,,supplement ,,no4 #dda ,,new ,,york1 ,,june #ad1 #ahhd ,scientific ,american ,supplement4 ,vol4 ,,xvii41 ,no4 #dda4 ,scientific ,american established #ahde ,scientific ,american ,supplement1 #e a year4 ,scientific ,american and ,supplement1 #g a year4 99 99 99 99 99 ,,table ,,of ,,contents4 ,i4 ,,chemistry ,,and ,,metallurgy4--,on ,electrolysis4--,precipitation of lead1 thallium1 silver1 bismuth1 manganese1 etc4--,by ,h4 ,,schucht ,the ,electro-,chemical ,equivalent of ,silver ,zircon4--,how it can be rendered soluble4--,by ,f4 ,,stolba ,a ,new ,process for ,making ,wrought ,iron ,directly from the ,ore4 --,comparison with other processes4--,with descriptions and engravings of the apparatus used ,some ,remarks on the ,determination of ,hardness in ,water ,on the changes which ,take ,place in the ,conversion of ,hay into ,ensilage4--,by ,f4,j4 ,lloyd ,,ii4 ,,engineering ,,and ,,mechanics4--,faure's ,machine for ,decorticating ,sugar ,cane4--,with full description and #ac figures ,the ,generation of ,steam and the ,thermodynamic ,problems ,involved4--,by ,,wm4 ,,anderson4--,apparatus used in the experimental determination of the heat of combustion and the laws which govern its development4--,ingredients of fuel4--,potential energy of fuel4--,with #g figures and several tables ,planetary ,wheel ,trains4--,rotations of the wheels relatively to the train arm4--,by ,prof4 ,c4,w4 ,,maccord ,the ,pantanemone4--,a ,new ,windwheel4--#a engraving ,relvas's ,new ,life ,boat4--,with engraving ,experiments with ,double ,barreled ,guns and ,rifles4 --,cause of the divergence of the charge4--#d figures ,improved ,ball ,turning ,machine4--#a figure ,cooling ,apparatus for ,injection ,water4--,with engraving ,corrugated ,disk ,pulleys4--#a engraving ,,iii4 ,,technology4--,a ,new ,standard ,light ,dr4 ,feussner's ,new ,polarizing ,prism4--,points of difference between the old and new prisms4--,by ,p4,r4 ,,sleeman ,density and ,pressure of ,detonating ,gas ,,iv4 ,,electricity1 ,,light1 ,,etc4--,early ,history of the ,telegraph4 --,pyrsia1 or the system of telegraphy among the ,greeks4 --,communication by means of characters and the telescope4 --,introduction of the magnetic telegraph between ,baltimore and ,washington ,the ,kravogl ,electro ,motor and its ,conversion ,into a ,dynamo ,electric ,machine4--#e figures ,bornhardt's ,electric ,machine for ,blasting in ,mines4 --#ae figures ,pritchett's ,electric ,fire ,alarm4--#a figure ,a ,standard ,thermopile ,telephonic ,transmission without ,receivers4--,some of the apparatus exhibited at the annual meeting of the ,french ,society of ,physics4--,telephonic transmission through a chain of persons ,diffraction ,phenomena during ,total ,solar ,eclipses4--,by ,g4,d4 ,hiscox ,v4 ,,botany ,,and ,,horticulture4--,gum ,diseases in ,trees4-- ,cause and contagion of the same ,drinkstone ,park4--,trees and plants cultivated therein4-- ,with #b engravings ,,vi4 ,,medicine ,,and ,,hygiene4--,miryachit4--,a newly-discovered disease of the nervous system1 and its analogues4--,by ,,wm4 ,a4 ,,hammond ,,vii4 ,,miscellaneous4--,turkish ,baths for ,horses4--,with diagram4 99 99 99 99 99 ,,faure',s ,,machine ,,for ,,decorticating ,,sugar-,,cane4 ,the object of the apparatus shown in the accompanying engraving is to effect a separation of the tough epidermis of the sugar-cane from the internal spongy pith which is to be pressed4 ,its function consists in isolating and separating the cells from their cortex1 and in putting them in direct contact with the rollers or cylinders of the mill4 ,after their passage into the apparatus1 which is naturally placed in a line with the endless chain that carries them to the mill1 the canes arrive in less compact layers1 pass through much narrower spaces1 and finally undergo a more efficient pressure1 which is shown by an abundant flow of juice4 ,the first trials of the machine were made in #ahgi at the ,pointe ,simon ,works1 at ,martinique1 with the small type that was shown at the ,paris ,exhibition of #ahgh4 ,these experiments1 which were applied to a work of #c1jjj kilos of cane per hour1 gave entire satisfaction1 and decided the owners of three of the colonial works 7,pointe ,simon1 ,larcinty1 and ,marin7 to adopt it for the season of #ahhj4 ,the apparatus is shown in longitudinal section in ,fig4 #a1 and in plan in ,fig4 #b4 ,fig4 #c gives a transverse section passing through the line #c-d1 and ,fig4 #d an external view on the side whence the decorticated canes make their exit from the apparatus4 ,illustration3 ,,faure',s ,,machine ,,for ,,decorticating ,,sugar ,,cane4 ,the other figures relate to details that will be referred to further along4 ,the ,decorticating ,cylinder4--,the principal part of the apparatus is a hollow drum1 ,a1 of cast iron1 #dcj mm4 in internal diameter by #a4da m4 in length1 which is keyed at its two extremities to the shaft1 a4 ,externally1 this drum 7which is represented apart in transverse section in ,fig4 #e7 has the form of an octagonal prism with well dressed projections between which are fixed the eight plates1 ,c1 that constitute the decorticating cylinder4 ,these plates1 which are of tempered cast iron1 and one of which is shown in transverse section in ,fig4 #g1 when once in place form a cylindrical surface provided with #dh helicoidal1 dentate channels4 ,the length of these plates is #dgj mm4 ,there are three of them in the direction of the generatrices of the cylinder1 and this makes a total of #bd4 ,all are strengthened by ribs 7as shown in ,fig4 #h71 and each is fixed by #d bolts1 c1 #bjmm4 in diameter4 ,the pitch of the helices of each tooth is very elongated1 and reaches about #g4eb m4 ,the depth of the toothing is #ah mm4 ,frame and ,endless ,chain4--,the cylinder thus constructed rotates with a velocity of #ej revolutions per minute over a cylindrical vessel1 ,b'1 cast in a piece with the frame1 ,b4 ,this vessel is lined with two series of tempered cast iron plates1 ,d and ,d'1 called exit and entrance plates1 which rest thereon1 through the intermedium of well dressed pedicels1 and which are held in place by six #bj-millimeter bolts4 ,their length is #gjh mm4 ,the entrance plates1 ,d1 are provided with #f spiral channels1 whose pitch is equal to that of the channels of the decorticating cylinder1 ,c1 and in the same direction4 ,the depth of the toothing is #aj mm4 ,the exit plates1 ,d'1 are provided with #g spiral channels of the same pitch and direction as those of the preceding1 but the depth of which increases from #b to #aj mm4 ,the axis of the decorticating cylinder does not coincide with that of the vessel1 ,b'1 so that the free interval for the passage of the cane continues to diminish from the entrance to the exit4 ,the passage of the cane to the decorticator gives rise to a small quantity of juice1 which flows through two orifices1 b'1 into a sort of cast iron trough1 ,g1 suspended beneath the vessel4 ,the cane1 which is brought to the apparatus by an endless belt1 empties in a conduit formed of an inclined bottom1 ,e1 of plate iron1 and two cast iron sides provided with ribs4 ,these sides rest upon the two ends of the vessel1 ,b'1 and are cross-braced by two flat bars1 e1 to which is bolted the bottom1 ,e4 ,this conduit is prolonged beyond the decorticating cylinder by an inclined chute1 ,f1 the bottom of which is made of plate iron #g mm4 thick and the sides of the same material #i mm4 thick4 ,the hollow frame1 ,b1 whose general form is like that of a saddle1 carries the bearings1 b1 in which revolves the shaft1 a4 ,one of these bearings is represented in detail in ,figs4 #i and #aj4 ,it will be seen that the cap is held by bolts with sunken heads1 and that the bearing on the bushes is through horizontal surfaces only4 ,in a piece with this frame are cast two similar brackets1 ,b1 which support the axle1 h1 of the endless chain4 ,to this axle1 whose diameter is #ajj mm41 are keyed1 toward the extremities1 the pinions1 ,h1 to which correspond the endless pitch chains1 i4 ,these latter are formed1 as may be seen in ,figs4 #aa and #ab1 of two series of links4 ,the shorter of these latter are only #ajj mm4 in length1 while the longer are #baj mm41 and are hollowed out so as to receive the butts of the boards1 ,i4 ,the chain thus formed passes over two pitch pinions1 ,j1 like the pinions1 ,h1 that are mounted at the extremities of an axle1 j1 that revolves in bearings1 ,i'1 whose position with regard to the apparatus is capable of being varied so as to slacken or tauten the chain1 ,i4 ,this arrangement is shown in elevation in ,fig4 #ac4 ,transmission4--,the driving shaft1 k1 revolves in a pillow block1 ,k1 cast in a piece with the frame1 ,b4 ,it is usually actuated by a special motor1 and carries a fly-wheel 7not shown in the figure for want of space74 ,it receives in addition a cog-wheel1 ,l1 which transmits its motion to the decorticating cylinder through1 the intermedium of a large wooden-toothed gear wheel1 ,l'4 ,the shaft1 a1 whose diameter is #bbh mm41 actuates in its turn1 through the pinions1 ,m' and ,m1 the pitch pinion1 ,n1 upon whose prolonged hub is keyed the pinion1 ,m4 ,this latter is mounted loosely upon the intermediate axle1 m4 ,motion is transmitted to the driving shaft1 h1 of the endless chain1 ,i1 by an ordinary pitch chain1 through a gearing which is shown in ,fig4 #ab4 ,the pitch pinion1 ,n'1 is cast in a piece with a hollow friction cone1 ,n1 which is mounted loosely upon the shaft1 h1 and to which corresponds a second friction cone1 ,o4 ,this latter is connected by a key to a socket1 o1 upon which it slides1 and which is itself keyed to the shaft1 h4 ,the hub of the cone1 ,o1 is connected by a ring with a bronze nut1 p1 mounted at the threaded end of the shaft1 h1 and carrying a hand-wheel1 ,p4 ,it is only necessary to turn this latter in one direction or the other in order to throw the two cones into or out of gear4 ,if we allow that the motor has a velocity of #gj revolutions per minute1 the decorticating cylinder will run at the rate of #ej1 and the sugar-cane will move forward at the rate of #ab meters per minute4 ,this new machine is a very simple and powerful one4 ,the decortication is effected with wonderful rapidity1 and the canes1 opened throughout their entire length and at all points of their circumference1 leave the apparatus in a state that allows of no doubt as to what the result of the pressure will be that they have to undergo4 ,there is no tearing1 no trituration1 no loss of juice1 but merely a simple preparation for a rational pressure effected under most favorable conditions4 ,the apparatus1 which is made in several sizes1 has already received numerous applications in ,martinique1 ,trinidad1 ,cuba1 ,antigua1 ,st4 ,domingo1 ,peru1 ,australia1 the ,mauritius ,islands1 and ,brazil4--,publication ,industrielle4 99 99 99 99 99 ,,moving ,a ,,bridge4 ,an interesting piece of engineering work has recently been accomplished at ,bristol1 ,england1 which consisted in the moving of a foot-bridge #acd feet in length1 bodily1 down the river a considerable distance4 ,the pontoons by means of which the bridge was floated to its new position consisted of four #hj-ton barges1 braced together so as to form one solid structure #fd feet in width1 and were placed in position soon after the tide commenced to rise4 ,at six o'clock ,a4,m4 the top of the stages1 which was #bd feet above the water1 touched the under part of the bridge1 and in a quarter of an hour later both ends rose from their foundations4 ,when the tide had risen #d ft4 the stage and bridge were floated to the new position1 when at #h4cj the girders dropped on to their beds4 99 99 99 99 99 ,,the ,,generation ,,of ,,steam1 ,,and ,,the ,,thermodynamic ,,problems ,,involved4#a ,footnote #a3 ,lecture delivered at the ,institution of ,civil ,engineers1 session #ahhc-hd4 ,for the illustrations we are indebted to the courtesy of ,mr4 ,j4 ,forrest1 the secretary4 ,by ,mr4 ,,william ,,anderson1 ,m4,i4,c4,e4 ,it will not be necessary to commence this lecture by explaining the origin of fuel2 it will be sufficient if ,i remind you that it is to the action of the complex rays of the sun upon the foliage of plants that we mainly owe our supply of combustibles4 ,the tree trunks and branches of our forests1 as well as the subterranean deposits of coal and naphtha1 at one time formed portions of the atmosphere in the form of carbonic acid gas2 that gas was decomposed by the energy of the solar rays1 the carbon and the oxygen were placed in positions of advantage with respect to each other--endowed with potential energy2 and it is my duty this evening to show how we can best make use of these relations1 and by once more combining the constituents of fuel with the oxygen of the air1 reverse the action which caused the growth of the plants1 that is to say1 by destroying the plant reproduce the heat and light which fostered it4 ,the energy which can be set free by this process cannot be greater than that derived originally from the sun1 and which1 acting through the frail mechanism of green leaves1 tore asunder the strong bonds of chemical affinity wherein the carbon and oxygen were hound1 converting the former into the ligneous portions of the plants and setting the latter free for other uses4 ,the power thus silently exerted is enormous2 for every ton of carbon separated in twelve hours necessitates an expenditure of energy represented by at least #a1jeh horse power1 but the action is spread over an enormous area of leaf surface1 rendered necessary by the small proportion of carbonic acid contained in the air1 by measure only #a_/bjjj part1 and hence the action is silent and imperceptible4 ,it is now conceded on all hands that what is termed heat is the energy of molecular motion1 and that this motion is convertible into various kinds and obeys the general laws relating to motion4 ,two substances brought within the range of chemical affinity unite with more or less violence2 the motion of transition of the particles is transformed1 wholly or in part1 into a vibratory or rotary motion1 either of the particles themselves or the interatomic ether2 and according to the quality of the motions we are as a rule1 besides other effects1 made conscious of heat or light1 or of both4 ,when these emanations come to be examined they are found to be complex in the extreme1 intimately bound up together1 and yet capable of being separated and analyzed4 ,as soon as the law of definite chemical combination was firmly established1 the circumstance that changes of temperature accompanied most chemical combinations was noticed1 and chemists were not long in suspecting that the amount of heat developed or absorbed by chemical reaction should be as much a property of the substances entering into combination as their atomic weights4 ,solid ground for this expectation lies in the dynamic theory of heat4 ,a body of water at a given height is competent by its fall to produce a definite and invariable quantity of heat or work1 and in the same way two substances falling together in chemical union acquire a definite amount of kinetic energy1 which1 if not expended in the work of molecular changes1 may also by suitable arrangements be made to manifest a definite and invariable quantity of heat4 ,at the end of last century ,lavoisier and ,laplace1 and after them1 down to our own time1 ,dulong1 ,desprez1 ,favre and ,silbermann1 ,andrews1 ,berthelot1 ,thomson1 and others1 devoted much time and labor to the experimental determination of the heat of combustion and the laws which governed its development4 ,messrs4 ,favre and ,silbermann1 in particular1 between the years #ahde and #aheb1 carried out a splendid series of experiments by means of the apparatus partly represented in ,fig4 #a 7opposite71 which is a drawing one-third the natural size of the calorimeter employed4 ,it consisted essentially of a combustion chamber formed of thin copper1 gilt internally4 ,the upper part of the chamber was fitted with a cover through which the combustible could be introduced1 with a pipe for a gas jet1 with a peep hole closed by adiathermanous but transparent substances1 alum and glass1 and with a branch leading to a thin copper coil surrounding the lower part of the chamber and descending below it4 ,the whole of this portion of the apparatus was plunged into a thin copper vessel1 silvered internally and filled with water1 which was kept thoroughly mixed by means of agitators4 ,this second vessel stood inside a third one1 the sides and bottom of which were covered with the skins of swans with the down on1 and the whole was immersed in a fourth vessel tilled with water1 kept at the average temperature of the laboratory4 ,suitable thermometers of great delicacy were provided1 and all manner of precautions were taken to prevent loss of heat4 ,illustration3 ,,the ,,generation ,,of ,,steam4 ,fig #a4 ,it is impossible not to admire the ingenuity and skill exhibited in the details of the apparatus1 in the various accessories for generating and storing the gases used1 and for absorbing and weighing the products of combustion2 but it is a matter of regret that the experiments should have been carried out on so small a scale4 ,for example1 the little cage which held the solid fuel tested was only #e_/h inch diameter by barely #b inches high1 and held only #ch grains of charcoal1 the combustion occupying about sixteen minutes4 ,favre and ,silbermann adopted the plan of ascertaining the weight of the substances consumed by calculation from the weight of the products of combustion4 ,carbonic acid was absorbed by caustic potash1 as also was carbonic oxide1 after having been oxidized to carbonic acid by heated oxide of copper1 and the vapor of water was absorbed by concentrated sulphuric acid4 ,the adoption of this system showed that it was in any case necessary to analyze the products of combustion in order to detect imperfect action4 ,thus1 in the case of substances containing carbon1 carbonic oxide was always present to a variable extent with the carbonic acid1 and corrections were necessary in order to determine the total heat due to the complete combination of the substance with oxygen4 ,another advantage gained was that the absorption of the products of combustion prevents any sensible alteration in the volumes during the process1 so that corrections for the heat absorbed in the work of displacing the atmosphere were not required4 ,the experiments on various substances were repeated many times4 ,the mean results for those in which we are immediately interested are given in ,table ,i41 next column4 ,comparison with later determinations have established their substantial accuracy4 ,the general conclusion arrived at is thus stated3 ,as a rule there is an equality between the heat disengaged or absorbed in the acts1 respectively1 of chemical combination or decomposition of the same elements1 so that the heat evolved during the combination of two simple or com-pound substances is equal to the heat absorbed at the time of their chemical segregation4 ,,table ,i4--,,substances ,,entering ,,into ,,the ,,composition ,,of ,,fuel4 ---------------------------------------- -------------------------- ,heat evolved in ,symbol and ,atomic the ,combustion of ,weight4 #a lb4 of ,fuel4 ---------------------------------------- -- ,in ,pounds ,in of ,water ,british ,evaporated ,before ,after ,thermal from and ,combustion ,combustion ,units4 at #bab4 ---------------------------------------- -- ,hydrogen burned ,h #a ,h#b,o #ah #fb1jcb #fd4ba in oxygen4 ---------------------------------------- ------------------------- ,carbon burned to ,c #ab ,,co #bh #d1dea #d4fa carbonic oxide4 ---------------------------------------- ------------------------- ,carbon burned to ,c #ab ,,co#b #dd #ad1edd #ae4jf carbonic acid4 ---------------------------------------- ------------------------- ,carbonic oxide burned ,,co #bh ,,co#b #dd #d1cbf #d4dh to carbonic acid4 ---------------------------------------- ------------------------- ,olefiant gas 7ethylene7 ,c#b;,h#d #bh #b;,,co#b #abd #ba1cdc #bb4ji burnt in oxygen4 #b;,h#b,o ---------------------------------------- ------------------------- ,marsh gas 7methane7 ,,ch#d #af #b;,,co#b #hj #bc1eac #bd4cd burnt in oxygen4 #b;,h#b,o ---------------------------------------- ------------------------- ,composition of air-- by volume #j4ghh ,n #j4aig ,o #j4jja ,,co#b #j4jad ,h#b,o ---------------------------------------- ------------ by weight #j4gga ,n #j4bah ,o #j4jji ,,co#b #j4jag ,h#b,o ,this law is1 however1 subject to some apparent exceptions4 ,carbon burned in protoxide of nitrogen1 or laughing gas1 ,n#b,o1 produces about #ch per cent4 more heat than the same substance burned in pure oxygen1 notwithstanding that the work of decomposing the protoxide of nitrogen has to be performed4 ,in marsh gas1 or methane1 ,,ch#d1 again1 the energy of combustion is considerably less than that due to the burning of its carbon and hydrogen separately4 ,these exceptions probably arise from the circumstance that the energy of chemical action is absorbed to a greater or less degree in effecting molecular changes1 as1 for example1 the combustion of #a pound of nitrogen to form protoxide of nitrogen results in the absorption of #a1aeg units of heat4 ,berthelot states1 as one of the fundamental principles of thermochemistry1 that the quantity of heat evolved is the measure of the sum of the chemical and physical work accomplished in the reaction2 and such a law will no doubt account for the phenomena above noted4 ,the equivalent heat of combustion of the compounds we have practically to deal with has been experimentally determined1 and therefore constitutes a secure basis on which to establish calculations of the caloric value of fuel2 and in doing so1 with respect to substances composed of carbon1 hydrogen1 and oxygen1 it is convenient to reduce the hydrogen to its heat-producing equivalent of carbon4 ,the heat of combustion of hydrogen being #fb1jcb units1 that of carbon #ad1edd units1 it follows that #d4bfe times the weight of hydrogen will represent an equivalent amount of carbon4 ,with respect to the oxygen1 it is found that it exists in combination with the hydrogen in the form of water1 and1 being combined already1 abstracts its combining equivalent of hydrogen from the efficient ingredients of the fuel2 and hence hydrogen1 to the extent of #a_/h of the weight of the oxygen1 must be deducted4 ,the general formula then becomes3 ,heat of combustion #ad1edd ,c #d4bfe 7,h-7,o_/#h771 and water evaporated from and at #bab1 taking #iff units as the heat necessary to evaporate #a pound of water1 lb4 evaporated #ae4jf ,c #d4bfe 7,h-7,o_/#h771 carbon1 hydrogen1 and oxygen being taken at their weight per cent4 in the fuel4 ,strictly speaking1 marsh gas should be separately determined4 ,it often happens that available energy is not in a form in which it can be applied directly to our needs4 ,the water flowing down from the mountains in the neighborhood of the ,alpine tunnels was competent to provide the power necessary for boring through them1 but it was not in a form in which it could be directly applied4 ,the kinetic energy of the water had first to be changed into the potential energy of air under pressure1 then1 in that form1 by suitable mechanism1 it was used with signal success to disintegrate and excavate the hard rock of the tunnels4 ,the energy resulting from combustion is also incapable of being directly transformed into useful motive power2 it must first be converted into potential force of steam or air at high temperature and pressure1 and then applied by means of suitable heat engines to produce the motions we require4 ,it is probably to this circumstance that we must attribute the slowness of the human race to take advantage of the energy of combustion4 ,the history of the steam engine hardly dates back #bjj years1 a very small fraction of the centuries during which man has existed1 even since historic times4 ,the apparatus by means of which the potential energy of fuel with respect to oxygen is converted into the potential energy of steam1 we call a steam boiler2 and although it has neither cylinder nor piston1 crank nor fly wheel1 ,i claim for it that it is a veritable heat engine1 because it transmits the undulations and vibrations caused by the energy of chemical combination in the fuel to the water in the boiler2 these motions expend themselves in overcoming the liquid cohesion of the water and imparting to its molecules that vigor of motion which converts them into the molecules of a gas which1 impinging on the surfaces which confine it and form the steam space1 declare their presence and energy in the shape of pressure and temperature4 ,a steam pumping engine1 which furnishes water under high pressure to raise loads by means of hydraulic cranes1 is not more truly a heat engine than a simple boiler1 for the latter converts the latent energy of fuel into the latent energy of steam1 just as the pumping engine converts the latent energy of steam into the latent energy of the pumped-up accumulator or the hoisted weight4 ,if ,i am justified in taking this view1 then ,i am justified in applying to my heat engine the general principles laid down in #ahbd by ,sadi ,carnot1 namely1 that the proportion of work which can be obtained out of any substance working between two temperatures depends entirely and solely upon the difference between the temperatures at the beginning and end of the operation2 that is to say1 if ,t be the higher temperature at the beginning1 and t the lower temperature at the end of the action1 then the maximum possible work to be got out of the substance will be a function of 7,t-t74 ,the greatest range of temperature possible or conceivable is from the absolute temperature of the substance at the commencement of the operation down to absolute zero of temperature1 and the fraction of this which can be utilized is the ratio which the range of temperature through which the substance is working bears to the absolute temperature at the commencement of the action4 ,if ,w the greatest amount of effect to be expected1 ,t and t the absolute temperatures1 and ,h the total quantity of heat 7expressed in foot pounds or in water evaporated1 as the case may be7 potential in the substance at the higher temperature1 ,t1 at the beginning of the operation1 then ,carnot's law is expressed by the equation3 _/ ,t - t ,w ,h7 ------- 7 ,t _/ ,i will illustrate this important doctrine in the manner which ,carnot himself suggested4 ,illustration3 ,,the ,,generation ,,of ,,steam4 ,fig #b4 ,fig4 #b represents a hillside rising from the sea4 ,some distance up there is a lake1 ,l1 fed by streams coming down from a still higher level4 ,lower down on the slope is a millpond1 ,p1 the tail race from which falls into the sea4 ,at the millpond is established a factory1 the turbine driving which is supplied with water by a pipe descending from the lake1 ,l4 ,datum is the mean sea level2 the level of the lake is ,t1 and of the millpond t4 ,q is the weight of water falling through the turbine per minute4 ,the mean sea level is the lowest level to which the water can possibly fall2 hence its greatest potential energy1 that of its position in the lake1 ,,qt ,h4 ,the water is working between the absolute levels1 ,t and t2 hence1 according to ,carnot1 the maximum effect1 ,w1 to be expected is-- _/ ,t - t ,w ,h7 ------- 7 ,t _/ _/ ,t - t but ,h ,,qt therefore ,w ,q ,t7 ------- 7 ,t _/ ,w ,q 7,t - t71 that is to say1 the greatest amount of work which can be expected is found by multiplying the weight of water into the clear fall1 which is1 of course1 self-evident4 ,now1 how can the quantity of work to be got out of a given weight of water be increased without in any way improving the efficiency of the turbine8 ,in two ways3 #a4 ,by collecting the water higher up the mountain1 and by that means increasing ,t4 #b4 ,by placing the turbine lower down1 nearer the sea1 and by that means reducing t4 ,now1 the sea level corresponds to the absolute zero of temperature1 and the heights ,t and t to the maximum and minimum temperatures between which the substance is working2 therefore similarly1 the way to increase the efficiency of a heat engine1 such as a boiler1 is to raise the temperature of the furnace to the utmost1 and reduce the heat of the smoke to the lowest possible point4 ,it should be noted1 in addition1 that it is immaterial what liquid there may be in the lake2 whether water1 oil1 mercury1 or what not1 the law will equally apply1 and so in a heat engine1 the nature of the working substance1 provided that it does not change its physical state during a cycle1 does not affect the question of efficiency with which the heat being expended is so utilized4 ,to make this matter clearer1 and give it a practical bearing1 ,i will give the symbols a numerical value1 and for this purpose ,i will1 for the sake of simplicity1 suppose that the fuel used is pure carbon1 such as coke or charcoal1 the heat of combustion of which is #ad1edd units1 that the specific heat of air1 and of the products of combustion at constant pressure1 is #j4bch1 that only sufficient air is passed through the fire to supply the quantity of oxygen theoretically required for the combustion of the carbon1 and that the temperature of the air is at #fj ,fahrenheit #ebj absolute4 ,the symbol ,t represents the absolute temperature of the furnace1 a value which is easily calculated in the following manner3 #a lb4 of carbon requires #b-b_/c lb4 of oxygen to convert it into carbonic acid1 and this quantity is furnished by #ab4b lb4 of air1 the result being #ac4b lb4 of gases1 heated by #ad1edd units of heat due to the energy of combustion2 therefore3 #ad1edd units ,t #ebj ------------------ #e1aej absolute4 #ac4b lb4 ,x #j4bch ,the lower temperature1 t1 we may take as that of the feed water1 say at #ajj or #efj absolute1 for by means of artificial draught and sufficiently extending the heating surface1 the temperature of the smoke may be reduced to very nearly that of the feed water4 ,under such circumstances the proportion of heat which can be realized is #e1aej - #efj --------------- #j4hia2 #e1aej that is to say1 under the extremely favorable if not impracticable conditions assumed1 there must be a loss of #aa per cent4 ,next1 to give a numerical value to the potential energy1 ,h1 to be derived from a pound of carbon1 calculating from absolute zero1 the specific heat of carbon being #j4be1 and absolute temperature of air #ebj3 ,units4 #a lb4 of carbon ,x #j4be ,x #ebj #acj #ab4b of air ,x #j4bch ,x #ebj #a1dhe ,heat of combustion #ad1edd ------ #af1aei ,deduct heat equivalent to work of displacing atmosphere by products of combustion raised from #fj to #ajj1 #cb or from #adi4h cubic feet to #afa4c cubic feet1 _/ ------ ,total units of heat available #af1abg ,equal to #af4fi lb4 of water evaporated from and at #bab4 ,hence the greatest possible evaporation from and at #bab from a lb4 of carbon-- #af1aei u4 ,x #j4hia - #cb u4 ,w --------------------------- #ad4hg lb4 #iff u4 ,i will now take a definite case1 and compare the potential energy of a certain kind of fuel with the results actually obtained4 ,for this purpose the boiler of the eight-horse portable engine1 which gained the first prize at the ,cardiff show of the ,royal ,agricultural ,society in #ahgb1 will serve very well1 because the trials1 all the details of which are set forth very fully in vol4 ix4 of the ,journal of the ,society1 were carried out with great care and skill by ,sir ,frederick ,bramwell and the late ,mr4 ,menelaus2 indeed1 the only fact left undetermined was the temperature of the furnace1 an omission due to the want of a trustworthy pyrometer1 a want which has not been satisfied to this day4#b ,footnote #b3 ,in the fifty-second volume of the ,proceedings 7#ahhg-gh71 page #aed1 will be found a remarkable experiment on the evaporative power of a vertical boiler with internal circulating pipes4 ,the experiment was conducted by ,sir ,frederick ,bramwell and ,dr4 ,russell1 and is remarkable in this respect1 that the quantity of air admitted to the fuel1 the loss by convection and radiation1 and the composition of the smoke were determined4 ,the facts observed were as follows3 ,steam pressure #ec lb44444444444444444444444444444444444 #cjj4f ,f4 lb4 ,fuel--,water in coke and wood444444444444444444444444444 #bf4jh ,ash444444444444444444444444444444444444 4444444444 #aj4ec ,hydrogen1 oxygen1 nitrogen1 and sulphur4444444444 #g4ah ------ ,total non-combustible444444444444444444444 #dc4gi ,carbon1 being useful combustible44444444444444444 #aid4df ------ ,total fuel44444444444444444444444444444444 #bch4be ,air per pound of carbon44444444444444444444444444444444 #ag-a_/h lb4 ,time of experiment444444444444444444444444444444 4444444 #d h4 #ab min4 ,water evaporated from #fj into steam at #ec lb4 pressure #a1fbj lb4 ,heat lost by radiation and convection444444444444444444 #gj1dcj units4 ,mean temperature of chimney4444444444444444444444444444 #gjj ,f4 air44444444444444444444444444444444 #gj ,f4 ,no combustible gas was found in the chimney4 ,i will apply ,carnot's doctrine to this case4 ,potential energy of the fuel with respect to absolute zero3 ,units4 #bci4be lb4 #ecj abs4 #j4bch 4444444444444444444444 #cj1jec #aid4df lb4 #ag-a_/h #ecj #j4bch1 the weight and heat of air44444444444444444444444 #dbj1ffj #aid4df #ad1edd units heat of combustion of carbon444 #b1hbh1bjj --------- ,total energy #c1bgh1hac ,heat absorbed in evaporating #bf4jh lb4 of water in fuel444444444444444444444444444444444444 44444444 -#bi1hhh --------- ,available energy44444444444444444444444444 #c1bdh1dbe ,temperature of furnace-- ,the whole of the fuel was heated up1 but the heat absorbed in the evaporation of the water lowered the temperature of the furnace1 and must be deducted from the heat of combustion4 ,units4 ,heat of combustion444444444444444444444444444444 44444 #b1hbh1bjj evaporation of #bf4jh lb4 water444444444444444 -#bi1hhh --------- ,available heat of combustion44444444444444 #b1gih1cab ,dividing by #bch4be lb4 gives the heat per #a lb4 of fuel used44444444444444444444444444444444444 #aa1gde units4 ,and temperature of furnace3 #aa1gde units_/7#ah4abe lb4 #j4bch7 #ecj444444444 #c1bec ,temperature of chimney #gjj #dfj444444444444444 #a1afj ,maximum duty 7#c1bec - #a1afj7_/c1bec444444444444 #j4fdc ,work of displacing atmosphere by smoke at #gjj3 ,cubic feet4 ,volumes of gases at #gj444444444444444444444444 #bbh4c #gjj444444444444444444444444 #dii4h ----- ,increase of volume44444444444444444444 #bga4e ,units4 ,work done 7#aid4df lb4 #bga4e cub4 ft4 #add sq4 in4 #ae lb47 _/#gbb units 4444444444444444444444444444444444444 #adg1gbj ,maximum amount of work to be expected #c1bdh1dbe #j4fdc444444444444444444444444444444 #b1aja1gjj ,deduct work of displacing atmosphere4444444444444 #adg1gbj --------- ,available work444444444444444444444444 #a1iec1ihj ,actual work done3 ,units4 #a1fbj lb4 of water raised from #fj and turned into steam at #ec lb44444 4444444444444444444444 #a1hee1ijj ,loss by radiation and convection44444444444444444 #gj1dcj #aj-a_/b lb4 ashes left1 say at #ejj444444444444444 #a1abi --------- ,total work actually done44444444444444 #a1ibg1dei ,unaccounted for4444444444444444444444444444444444 #bf1eba --------- ,calculated available work444444444444444444444444 #a1iec1ihj ,the unaccounted-for work1 therefore1 amounts to only #a per cent4 of the calculated available work4 ,sir ,frederick ,bramwell ingeniously arranged his data in the form of a balance sheet1 and showed #bec1igi units unaccounted for2 but if from this we deduct the work lost in displacing the air1 the unaccounted-for heat falls to less than #d per cent4 of the total heat of combustion4 ,these results show how extremely accurate the observations must have been1 and that the loss mainly arises from convection and radiation from the boiler4 ,the data necessary for our purpose are3 ,steam pressure #hj lb4 temperature #cbd #ghd absolute4 ,mean temperature of smoke #chi #hdi ,water evaporated per #a lb of coal1 from and at #bab #aa4hc lb4 ,temperature of the air #fj #ebj absolute4 of feed water #bji #ffi ,heating surface #bbj square feet4 ,grate surface #c4bi feet4 ,coal burnt per hour #da lb4 ,the fuel used was a smokeless ,welsh coal1 from the ,llangennech colleries4 ,it was analyzed by ,mr4 ,snelus1 of the ,dowlais ,ironworks1 and in ,table ,,ii4 are exhibited the details of its composition1 and the weight and volume of air required for its combustion4 ,the total heat of combustion in #a lb of water evaporated3 #ae4jf 7#j4hdig #d4bfe 7#j4dbf - #j4jce_/h77 #ae4bd lb4 of water from and at #bab #ad1gbg units of heat4 ,,table ,,ii4--,,properties ,,of ,,llangennech ,,coal4 ---------------------------------------- ------------------------ ,products of ,oxygen ,combustion at #cb ,f4 ,analyses required -------------------- of #a lb4 for of ,coal4 ,combustion4 ,cubic ,volume ,pounds4 feet4 per cent4 ---------------------------------------- ----------------------- ,carbon44444444444 #j4hdig #b4bff #be4c #aa4a ,hydrogen444444444 #j4jdbf #j4cji #g4f #c4d ,oxygen44444444444 #j4jcej --- --- --- ,sulphur4444444444 #j4jjdb --- --- --- ,nitrogen444444444 #j4ajde --- #j4ah ,ash44444444444444 #j4jedj --- --- ---------------------- #he4e ,total44444444444 #a4jjjj #b4egb --- #i-a_/c4lb nitrogen --- --- #aah4i #f lb4 excess of air4 --- --- #ga4d ---------------------------------------- -- ,total cubic feet of products per #a lb4 of coal44444444444 -- -- #bbf4d #ajj4j ---------------------------------------- ----------------------- ,the temperature of the furnace not having been determined1 we must calculate it on the supposition1 which will be justified later on1 that #ej per cent more air was admitted than was theoretically necessary to supply the oxygen required for perfect combustion4 ,this would make #ah lb4 of air per #a lb4 of coal2 consequently #ai lb4 of gases would be heated by #ad1gbg units of heat4 ,hence3 #ad1gbg u4 ,t ---------------- #c1beg #ai lb4 #j4bch above the temperatures of the air1 or #c1ggg absolute4 ,the temperature of the smoke1 t1 was #hdi absolute2 hence the maximum duty would be #c1ggg - #hdi --------------- #j4ggeb4 #c1ggg ,the specific heat of coal is very nearly that of gases at constant pressure1 and may1 without sensible error1 be taken as such4 ,the potential energy of #a lb4 of coal1 therefore1 with reference to the oxygen with which it will combine1 and calculated from absolute zero1 is3 ,units4 #ai lb4 of coal and air at the temperature of the air contained #ai lb4 #ebj #j4bch #b1cej ,heat of combustion #ad1gbg ------- #ag1jgh ,deduct heat expended in displacing atmosphere #aea cubic feet - #dbb ------ ,total potential energy #af1fef ,hence work to be expected from the boiler3 _/ #c1ggg - #hdi #ag1jgh units ,x 7 --------------- 7 - #dbb units #c1ggg _/ ---------------------------------------- ------ #ac4bg lb4 #iff units of water evaporated from and at #bab1 corresponding to #ab1hai units4 ,the actual result obtained was #aa4hc lb42 hence the efficiency of this boiler was #aa4hc ------- #j4hib4 #ac4bg ,i have already claimed for a boiler that it is a veritable heat engine1 and ,i have ventured to construct an indicator diagram to illustrate its working4 ,the rate of transfer of heat from the furnace to the water in the boiler1 at any given point1 is some way proportional to the difference of temperature1 and the quantity of heat in the gases is proportional to their temperatures4 ,draw a base line representing -#dfj ,fahr41 the absolute zero of temperature4 ,at one end erect an ordinate1 upon which set off ,t #c1ggg1 the temperature of the furnace4 ,at #hdi t1 on the scale of temperature1 draw a line parallel to the base1 and mark on it a length proportional to the heating surface of the boiler2 join ,t by a diagonal with the extremity of this line1 and drop a perpendicular on to the zero line4 ,the temperature of the water in the boiler being uniform1 the ordinates bounded by the sloping line1 and by the line1 t1 will at any point be approximately proportional to the rate of transmission of heat1 and the shaded area above t will be proportional to the quantity of heat imparted to the water4 ,join ,t by another diagonal with extremity of the heating surface on the zero line1 then the larger triangle1 standing on the zero line1 will represent the whole of the heat of combustion1 and the ratio of the two triangles will be as the lengths of their respective bases1 that is1 as 7,t - t7 _/ ,t1 which is the expression we have already used4 ,the heating surface was #bbj square feet1 and it was competent to transmit the energy developed by #da lb4 of coal consumed per hour #ab1hai u4 #da u4 #ebe1egb units1 equal to an average of #b1chi units per square foot per hour2 this value will correspond to the mean pressure in an ordinary diagram1 for it is a measure of the energy with which molecular motion is transferred from the heated gases to the boiler-plate1 and so to the water4 ,the mean rate of transmission1 multiplied by the area of heating surface1 gives the area of the shaded portion of the figure1 which is the total work which should have been done1 that is to say1 the work of evaporating #edd lb4 of water per hour4 ,the actual work done1 however1 was only #dhe lb4 ,to give the speculations we have indulged in a practical turn1 it will be necessary to examine in detail the terms of ,carnot's formula4 ,carnot labored under great disadvantages4 ,he adhered to the emission theory of heat2 he was unacquainted with its dynamic equivalent2 he did not know the reason of the difference between the specific heat of air at constant pressure and at constant volume1 the idea of an absolute zero of temperature had not been broached2 but the genius of the man1 while it made him lament the want of knowledge which he felt must be attainable1 also enabled him to penetrate the gloom by which he was surrounded1 and enunciate propositions respecting the theory of heat engines1 which the knowledge we now possess enables us to admit as true4 ,his propositions are3 #a4 ,the motive power of heat is independent of the agents employed to develop it1 and its quantity is determined solely by the temperature of the bodies between which the final transfer of caloric takes place4 #b4 ,the temperature of the agent must in the first instance be raised to the highest degree possible in order to obtain a great fall of caloric1 and as a consequence a large production of motive power4 #c4 ,for the same reason the cooling of the agent must be carried to as low a degree as possible4 #d4 ,matters must be so arranged that the passage of the elastic agent from the higher to the lower temperature must be due to an increase of volume1 that is to say1 the cooling of the agent must be caused by its rarefaction4 ,this last proposition indicates the defective information which ,carnot possessed4 ,he knew that expansion of the elastic agent was accompanied by a fall of temperature1 but he did not know that that fall was due to the conversion of heat into work4 ,we should state this clause more correctly by saying that the cooling of the agent must be caused by the external work it performs4 ,in accordance with these propositions1 it is immaterial what the heated gases or vapors in the furnace of a boiler may be1 provided that they cool by doing external work and1 in passing over the boiler surfaces1 impart their heat energy to the water4 ,the temperature of the furnace1 it follows1 must be kept as high as possible4 ,the process of combustion is usually complex4 ,first1 in the case of coal1 close to the fire-bars complete combustion of the red hot carbon takes place1 and the heat so developed distills the volatile hydrocarbons and moisture in the upper layers of the fuel4 ,the inflammable gases ignite on or near the surface of the fuel1 if there be a sufficient supply of air1 and burn with a bright flame for a considerable distance around the boiler4 ,if the layer of fuel be thin1 the carbonic acid formed in the first instance passes through the fuel and mixes with the other gases4 ,if1 however1 the layer of fuel be thick1 and the supply of air through the bars insufficient1 the carbonic acid is decomposed by the red hot coke1 and twice the volume of carbonic oxide is produced1 and this1 making its way through the fuel1 burns with a pale blue flame on the surface1 the result1 as far as evolution of heat is concerned1 being the same as if the intermediate decomposition of carbonic acid had not taken place4 ,this property of coal has been taken advantage of by the late ,sir ,w4 ,siemens in his gas producer1 where the supply of air is purposely limited1 in order that neither the hydrocarbons separated by distillation1 nor the carbonic oxide formed in the thick layer of fuel1 may be consumed in the producer1 but remain in the form of crude gas1 to be utilized in his regenerative furnaces4 ,illustration3 ,,the ,,generation ,,of ,,steam4 ,fig #c4 ,illustration3 ,,the ,,generation ,,of ,,steam4 ,fig #d4 ,illustration3 ,,the ,,generation ,,of ,,steam4 ,fig #e4 ,illustration3 ,,the ,,generation ,,of ,,steam4 ,fig #f4 ,illustration3 ,,the ,,generation ,,of ,,steam4 ,fig #g4 7,to be continued47 99 99 99 99 99 ,continued from ,,supplement ,no4 #dcg1 page #figj4 ,,planetary ,,wheel-,,trains4 ,by ,prof4 ,c4,w4 ,,maccord1 ,sc4,d4 ,,ii4 ,illustration3 ,,planetary ,,wheel ,,trains4 ,fig4 #ad ,it has already been shown that the rotations of all the wheels of a planetary train1 relatively to the train-arm1 are the same when the arm is in motion as they would be if it were fixed4 ,now1 in ,fig4 #ad1 let ,a be the first and ,f the last wheel of an incomplete train1 that is1 one having but one sun-wheel4 ,as before1 let these be so connected by intermediate gearing that1 when ,t is stationary1 a rotation of ,a through m degrees shall drive ,f through n degrees3 and also as before1 let ,t in the same time move through a degrees4 ,then1 if m' represent the total motion of ,a1 we have again1 m' m a1 or m m' - a4 ,this is1 clearly1 the motion of ,a relatively to the fixed frame of the machine2 and is measured from a fixed vertical line through the center of ,a4 ,now1 if we wish to express the total motion of ,f relatively to the same fixed frame1 we must measure it from a vertical line through the center of ,f1 wherever that maybe2 which gives in this case3 n' n a1 or n n' - a4 but with respect to the train-arm when at rest1 we have3 ang4 vel4 ,a n ------------ ---1 whence again ang4 vel4 ,f m n' - a n ------ --- 4 m' - a m ,this is the manner in which the equation is deduced by ,prof4 ,willis1 who expressly states that it applies whether the last wheel ,f is or is not concentric with the first wheel ,a1 and also that the train may be composed of any combinations which transmit rotation with both a constant velocity ratio and a constant directional relation4 ,he designates the quantities m'1 n'1 absolute revolutions1 as distinguished from the relative revolutions 7that is1 revolutions relatively to the train-arm71 indicated by the quantities m1 n3 adding1 ,hence it appears that the absolute revolutions of the wheels of epicyclic trains are equal to the sum of their relative revolutions to the arm1 and of the arm itself1 when they take place in the same direction1 and equal to the difference of these revolutions when in the opposite direction4 ,in this deduction of the formula1 as in that of ,prof4 ,rankine1 all the motions are supposed to have the same direction1 corresponding to that of the hands of the clock2 and in its application to any given train1 the signs of the terms must be changed in case of any contrary motion1 as explained in the preceding article4 ,and both the deduction and the application1 in reference to these incomplete trains in which the last wheel is carried by the train-arm1 clearly involve and depend upon the resolving of a motion of revolution into the components of a circular translation and a rotation1 in the manner previously discussed4 ,illustration3 ,,planetary ,,wheel ,,trains4 ,fig4 #ae ,to illustrate3 ,take the simple case of two equal wheels1 ,fig4 #ae1 of which the central one ,a is fixed4 ,supposing first ,a for the moment released and the arm to be fixed1 we see that the two wheels will turn in opposite directions with equal velocities1 which gives n_/m -#a2 but when ,a is fixed and ,t revolves1 we have m' #j1 whence in the general formula n' - a ------ -#a1 or n' #b a2 -a which means1 being interpreted1 that ,f makes two rotations about its axis during one revolution of ,t1 and in the same direction4 ,again1 let ,a and ,f be equal in the #c-wheel train1 ,fig4 #af1 the former being fixed as before4 ,in this case we have3 n --- #a1 m' #j1 which gives m n' - a ------- #a1 therefore n' #j2 -a that is to say1 the wheel ,f1 which now evidently has a motion of circular translation1 does not rotate at all about its axis during the revolution of the train-arm4 ,illustration3 ,,planetary ,,wheel ,,trains4 ,fig4 #af ,all this is perfectly consistent1 clearly1 with the hypothesis that the motion of circular translation is a simple one1 and the motion of revolution about a fixed axis is a compound one4 ,whether the hypothesis was made to substantiate the formula1 or the formula constructed to suit the hypothesis1 is not a matter of consequence4 ,in either case1 no difficulty will arise so long as the equation is applied only to cases in which1 as in those here mentioned1 that motion of revolution can be resolved into those components4 ,when the definition of an epicyclic train is restricted as it is by ,prof4 ,rankine1 the consideration of the hypothesis in question is entirely eliminated1 and whether it be accepted or rejected1 the whole matter is reduced to merely adding the motion of the train-arm to the rotation of each sun-wheel4 ,but in attempting to apply this formula in analyzing the action of an incomplete train1 we are required to add this motion of the train-arm1 not only to that of a sun-wheel1 but to that of a planet-wheel4 ,this is evidently possible in the examples shown in ,figs4 #ae and #af1 because the motions to be added are in all respects similar3 the trains are composed of spur-wheels1 and the motions1 whether of revolution1 translation1 or rotation1 take place in parallel planes perpendicular to parallel axes4 ,this condition1 which we have emphasized1 be it observed1 must hold true with regard to the motions of the first and last wheels and the train-arm1 in order to make this addition possible4 ,it is not essential that spur-wheels should be used exclusively or even at all2 for instance1 in ,fig4 #af1 ,a and ,f may be made bevel or screw-wheels1 without affecting the action or the analysis2 but the train-arm in all cases revolves around the central axis of the system1 that is1 about the axis of ,a1 and to this the axis of ,f must be parallel1 in order to render the deduction of the formula1 as made by ,prof4 ,willis1 and also by ,prof4 ,goodeve1 correct1 or even possible4 ,illustration3 ,,planetary ,,wheel ,,trains4 ,fig4 #ag ,this will be seen by an examination of ,fig4 #ag2 in which ,a and ,b are two equal spur-wheels1 ,e and ,f two equal bevel wheels1 ,b and ,e being secured to the same shaft1 and ,a being fixed to the frame ,h4 ,as the arm ,t goes round1 ,b will also turn in its bearings in the same direction3 let this direction be that of the clock1 when the apparatus is viewed from above1 then the motion of ,f will also have the same direction1 when viewed from the central vertical axis1 as shown at ,f'3 and let these directions be considered as positive4 ,it is perfectly clear that ,f will turn in its bearings1 in the direction indicated1 at a rate precisely equal to that of the train-arm4 ,let ,p be a pointer carried by ,f1 and ,r a dial fixed to ,t2 and let the pointer be vertical when ,,oo is the plane containing the axes of ,a1 ,b1 and ,e4 ,then1 when ,f has gone through any angle a measured from ,,oo1 the pointer will have turned from its original vertical position through an equal angle1 as shown also at ,f'4 ,now1 there is no conceivable sense in which the motion of ,t can be said to be added to the rotation of ,f about its axis1 and the expression absolute revolution1 as applied to the motion of the last wheel in this train1 is absolutely meaningless4 ,nevertheless1 ,prof4 ,goodeve states 7,elements of ,mechanism1 p4 #afe7 that ,we may of course apply the general formula in the case of bevel wheels just as in that of spur wheels4 ,let us try the experiment2 when the train-arm is stationary1 and ,a released and turned to the right1 ,f turns to the left at the same rate1 whence3 n --- -#a2 also m' #j when ,a is fixed1 m and the equation becomes n' - a ------ -#a1 therefore n' #b;a3 - a or in other words ,f turns twice on its axis during one revolution of ,t3 a result too palpably absurd to require any comment4 ,we have seen that this identical result was obtained in the case of ,fig4 #ae1 and it would1 of course1 be the same were the formula applied to ,figs4 #e and #f2 whereas it has never1 so far as we are aware1 been pretended that a miter or a bevel wheel will make more than one rotation about its axis in rolling once around an equal fixed one4 ,again1 if the formula be general1 it should apply equally well to a train of screw wheels3 let us take1 for example1 the single pair shown in ,fig4 #h1 of which1 when ,t is fixed1 the velocity ratio is unity4 ,the directional relation1 however1 depends upon the direction in which the wheels are twisted3 so that in applying the formula1 we shall have n_/m #a1 if the helices of both wheels are right handed1 and n_/m -#a1 if they are both left handed4 ,thus the formula leads to the surprising conclusion1 that when ,a is fixed and ,t revolves1 the planet-wheel ,b will revolve about its axis twice as fast as ,t moves1 in one case1 while in the other it will not revolve at all4 ,illustration3 ,,planetary ,,wheel ,,trains4 ,fig4 #ah ,a favorite illustration of the peculiarities of epicyclic mechanism1 introduced both by ,prof4 ,willis and ,prof4 ,goodeve1 is found in the contrivance known as ,ferguson's ,mechanical ,paradox1 shown in ,fig4 #ah4 ,this consists of a fixed sun-wheel ,a1 engaging with a planet-wheel ,b of the same diameter4 ,upon the shaft of ,b are secured the three thin wheels ,e1 ,g1 ,i1 each having #bj teeth1 and in gear with the three others ,f1 ,h1 ,k1 which turn freely upon a stud fixed in the train-arm1 and have respectively #ai1 #bj1 and #ba teeth4 ,in applying the general formula1 we have the following results3 n #bj n' - a #a ,for the wheel ,f1 --- ---- ---------1 therefore n' - ---- a4 m #ai -a #ai n n' - a ,h1 --- #a --------1 therefore n' #j4 m -a n #bj n' - a #a ,k1 --- ---- ---------1 therefore n' ---- a4 m #ba -a #ba ,the paradoxical appearance1 then1 consists in this1 that although the drivers of the three last wheels each have the same number of teeth1 yet the central one1 ,h1 having a motion of circular translation1 remains always parallel to itself1 and relatively to it the upper one seems to turn in the same direction as the train-arm1 and the lower in the contrary direction4 ,and the appearance is accepted1 too1 as a reality2 being explained1 agreeably to the analysis just given1 by saying that ,h has no absolute rotation about its axis1 while the other wheels have2 that of ,f being positive and that of ,k negative4 ,illustration3 ,,planetary ,,wheel ,,trains4 ,fig4 #ah ,the ,mechanical ,paradox1 it is clear1 may be regarded as composed of three separate trains1 each of which is precisely like that of ,fig4 #af3 and that1 again1 differs from the one of ,fig4 #ae only in the addition of a third wheel4 ,now1 we submit that the train shown in ,fig4 #ag is mechanically equivalent to that of ,fig4 #ae2 the velocity ratio and the directional relation being the same in both4 ,and if in ,fig4 #ag we remove the index ,p1 and fix upon its shaft three wheels like ,e1 ,g1 and ,i of ,fig4 #ah1 we shall have a combination mechanically equivalent to ,ferguson's ,paradox1 the three last wheels rotating in vertical planes about horizontal axes4 ,the relative motions of those three wheels will be the same1 obviously1 as in ,fig4 #ah2 and according to the formula their absolute motions are the same1 and we are invited to perceive that the central one does not rotate at all about its axis4 ,but it does rotate1 nevertheless2 and this unquestioned fact is of itself enough to show that there is something wrong with the formula as applied to trains like those in question4 ,what that something is1 we think1 has been made clear by what precedes2 since it is impossible in any sense to add together motions which are unlike1 it will be seen that in order to obtain an intelligible result in cases like these1 the equation must be of the form n'_/7m' - a7 n_/m4 ,we shall then have3 n #bj n' #bj ,for the wheel ,f1 --- ---- ----1 therefore n' - ---- a2 m #ai -a #ai n n' ,for the wheel ,h1 --- #a ----1 therefore n' -a2 m -a n #bj n' #bj ,for the wheel ,k1 --- ---- ----1 therefore n' - ---- a1 m #ba -a #ba which corresponds with the actual state of things2 all three wheels rotate in the same direction1 the central one at the same rate as the train arm1 one a little more rapidly and the third a little more slowly4 ,it is1 then1 absolutely necessary to make this modification in the general formula1 in order to apply it in determining the rotations of any wheel of an epicyclic train whose axis is not parallel to that of the sun-wheels4 ,and in this modified form it applies equally well to the original arrangement of ,ferguson's paradox1 if we abandon the artificial distinction between absolute and relative rotations of the planet-wheels1 and regard a spur-wheel1 like any other1 as rotating on its axis when it turns in its bearings2 the action of the device shown in ,fig4 #ah being thus explained by saying that the wheel ,h turns once backward during each forward revolution of the train-arm1 while ,f turns a little more and ,k a little less than once1 in the same direction4 ,in this way the classification and analysis of these combinations are made more simple and consistent1 and the incongruities above pointed out are avoided2 since1 without regard to the kind of gearing employed or the relative positions of the axes1 we have the two equations3 n' - a n ,i4 -------- ---1 for all complete trains2 m' - a m n' n ,,ii4 -------- ---1 for all incomplete trains4 m' - a m ,illustration3 ,,planetary ,,wheel ,,trains4 ,fig4 #ai ,as another example of the difference in the application of these formul1 let us take ,watt's sun and planet wheels1 ,fig4 #ai4 ,this device1 as is well known1 was employed by the illustrious inventor as a substitute for the crank1 which some one had succeeded in patenting4 ,it consists merely of two wheels ,a and ,f connected by the link ,t2 ,a being keyed on the shaft of the engine and ,f being rigidly secured to the connecting-rod4 ,suppose the rod to be of infinite length1 so as to remain always parallel to itself1 and the two wheels to be of equal size4 ,then1 according to ,prof4 ,willis' analysis1 we shall have-- n' - a n -s -------- --- -#a1 n' #j1 therefore -------- -#a1 whence m' - a m m' - a -a a - m'1 or m #b;a4 ,the other view of the question is1 that ,f turns once backward in its bearings during each forward revolution of ,t2 whence in ,eq4 #b we have-- n' n -------- --- -#a1 n' -a1 m' - a m -a therefore -------- -#a1 which gives -a a - m'1 or m' #b;a1 m' - a as before4 ,it is next to be remarked1 that the errors which arise from applying ,eq4 ,i4 to incomplete trains may in some cases counterbalance and neutralize each other1 so that the final result is correct4 ,illustration3 ,,planetary ,,wheel ,,trains4 ,fig4 #bj ,for example1 take the combination shown in ,fig4 #bj4 ,this consists of a train-arm ,t revolving about the vertical axis ,,oo of the fixed wheel ,a1 which is equal in diameter to ,f1 which receives its motion by the intervention of one idle wheel carried by a stud ,s fixed in the arm4 ,the second train-arm ,t' is fixed to the shaft of ,f and turns with it2 ,a' is secured to the arm ,t1 and ,f' is actuated by ,a' also through a single idler carried by ,t'4 ,we have here a compound train1 consisting of two simple planetary trains1 ,a--,f and ,a'--,f'2 and its action is to be determined by considering them separately4 ,first suppose ,t' to be removed and find the motion of ,f2 next suppose ,f to be removed and ,t fixed1 and find the rotation of ,f'2 and finally combine these results1 noting that the motion of ,t' is the same as that of ,f1 and the motion of ,a' the same as that of ,t4 ,then1 according to the analysis of ,prof4 ,willis1 we shall have 7substituting the symbol t for a in the equation of the second train1 in order to avoid confusion73 n n' - a #a4 ,train ,a--,f4 --- #a --------2 m' #j1 m m' - a n' - a whence -------- #a1 n' #j1 rot4 of ,f4 a n n' - t #b4 ,train ,a'--,f'4 --- #a --------2 m' #j1 m m' - t n' - t whence again -------- #a1 t #j1 rot4 of ,f'4 -t ,of these results1 the first is explicable as being the absolute rotation of ,f1 but the second is not2 and it will be readily seen that the former would have been equally absurd1 had the axis ,,ll been inclined instead of vertical4 ,but in either case we should find the errors neutralized upon combining the two1 for according to the theory now under consideration1 the wheel ,a'1 being fixed to ,t1 turns once upon its axis each time that train arm revolves1 and in the same direction2 and the revolutions of ,t' equal the rotations of ,f1 whence finally in train ,a'--,f' we have3 n n' - t #c4 --- #a --------2 in which t #j1 m' a1 m m' - t n' - #j which gives --------- #a1 or n' a4 a - #j ,this is1 unquestionably1 correct2 and indeed it is quite obvious that the effect upon ,f' is the same1 whether we say that during a revolution of ,t the wheel ,a' turns once forward and ,t' not at all1 or adopt the other view and assert that ,t' turns once backward and ,a' not at all4 ,but the latter view has the advantage of giving concordant results when the trains are considered separately1 and that without regard to the relative positions of the axes or the kind of gearing employed4 ,analyzing the action upon this hypothesis1 we have3 ,in train ,a--,f3 n n' n' --- #a --------2 m' #j1 therefore ---- #a1 or n' -a2 m m' - a -a ,in train ,a'--,f'3 n' n' n' --- #a --------2 m' #j1 therefore ---- #a1 or n' -t2 m m' - t -t ,in combining1 we have in the latter train m' #j1 t -a1 whence n n' n' --- #a -------- gives ---- #a1 or n' a1 as before4 m m' - t a ,now it happens that the only examples given by ,prof4 ,willis of incomplete trains in which the axis of a planet-wheel whose motion is to be determined is not parallel to the central axis of the system1 are similar to the one just discussed2 the wheel in question being carried by a secondary train-arm which derives its motion from a wheel of the primary train4 ,the application of his general equation in these cases gives results which agree with observed facts2 and it would seem that this circumstance1 in connection doubtless with the complexity of these compound trains1 led him to the too hasty conclusion that the formula would hold true in all cases2 although we are still left to wonder at his overlooking the fact that in these very cases the absolute and the relative rotations of the last wheel are identical4 ,illustration3 ,,planetary ,,wheel ,,trains4 ,fig4 #ba ,in ,fig4 #ba is shown a combination consisting also of two distinct trains1 in which1 however1 there is but one train-arm ,t turning freely upon the horizontal shaft ,,oo1 to which shaft the wheels ,a'1 ,f1 are secured2 the train-arm has two studs1 upon which turn the idlers ,b ,b'1 and also carries the bearings of the last wheel ,f'2 the first wheel ,a is annular1 and fixed to the frame of the machine4 ,let it be required to determine the results of one revolution of the crank ,h1 the numbers of teeth being assigned as follows3 ,a #fj1 ,f #cj1 ,a' #fj1 ,f' #aj4 ,we shall then have1 for the train ,,abf 7,eq4 ,i471 n #fj n' - a --- - ---- -#b --------1 in which n' #a1 m' #j1 m #cj m' - a' #a - a #a whence -#b -------1 #b;a #a - a1 #c;a #a1 a ---4 -a #c ,and for the train ,a',b',f' 7,eq4 ,,ii471 n #fj n' #a --- ---- #f --------1 in which a ---1 m' #a1 m #aj m' - a' #c n' whence #f -----------1 or n' #d4 #a - 7#a_/c7 ,that is1 the last wheel ,f' turns four times about the axis ,,ll during one revolution of the crank ,h4 ,but according to ,profs4 ,willis and ,goodeve1 we should have for the second train3 n #fj n' - a #a --- ---- #f --------1 in which a ---1 m' #a1 m #aj m' - a' #c n' - 7#a_/c7 which gives #f -----------1 n' - 7#a_/c7 #d1 n' #d-a_/c1 #a - 7#a_/c7 or four and one-third revolutions of ,f' for one of ,h4 ,this result1 no doubt1 might be near enough to the truth to serve all practical purposes in the application of this mechanism to its original object1 which was that of paring apples1 impaled upon the fork ,k2 but it can hardly be regarded as entirely satisfactory in a general way2 nor can the analysis which renders such a result possible4 99 99 99 99 99 ,,the ,,pantanemone4 ,the need of irrigating prairies1 inundating vines1 drying marshes1 and accumulating electricity cheaply has1 for some time past1 led to a search for some means of utilizing the forces of nature better than has ever hitherto been done4 ,wind1 which figures in the first rank as a force1 has thus far1 with all the mills known to us1 rendered services that are much inferior to those that we have a right to expect from it with improved apparatus2 for the work produced1 whatever the velocity of the wind1 has never been greater than that that could be effected by wind of seven meters per second4 ,but1 thanks to the experiments of recent years1 we are now obtaining an effective performance double that which we did with apparatus on the old system4 ,desirous of making known the efforts that have been made in this direction1 we lately described ,mr4 ,dumont's atmospheric turbine4 ,in speaking of this apparatus we stated that aerial motors generally stop or are destroyed in high winds4 ,recently1 ,mr4 ,sanderson has communicated to us the result of some experiments that he has been making for years back by means of an apparatus which he styles a pantanemone4 ,the engraving that we give of this machine shows merely a cabinet model of it2 and it goes without saying that it is simply designed to exhibit the principle upon which its construction is based4 ,illustration3 ,,the ,,pantanemone4 ,two plane surfaces in the form of semicircles are mounted at right angles to each other upon a horizontal shaft1 and at an angle of #de with respect to the latter4 ,it results from this that the apparatus will operate 7even without being set7 whatever be the direction of the wind1 except when it blows perpendicularly upon the axle1 thus permitting 7owing to the impossibility of reducing the surfaces7 of three-score days more work per year being obtained than can be with other mills4 ,three distinct apparatus have been successively constructed4 ,the first of these has been running for nine years in the vicinity of ,poissy1 where it lifts about #dj1jjj liters of water to a height of #bj meters every #bd hours1 in a wind of a velocity of from #g to #h meters per second4 ,the second raises about #aej1jjj liters of water to the ,villejuif reservoir1 at a height of #aj meters1 every #bd hours1 in a wind of from #e to #f meters4 ,the third supplies the laboratory of the ,montsouris observatory4 ,the first is not directible1 the second may be directed by hand1 and the third is directed automatically4 ,these three machines defied the hurricane of the #bfth of last ,january4--,la ,nature4 99 99 99 99 99 ,,relvas',s ,,new ,,life-,,boat4 ,the ,spanish and ,portuguese papers have recently made known some interesting experiments that have been made by ,mr4 ,carlos ,relvas with a new life-boat which parts the waves with great facility and exhibits remarkable stability4 ,this boat1 which is shown in front view in one of the corners of our engraving1 is ,t-shaped1 and consists of a very thin keel connected with the side-timbers by iron rods4 ,cushions of cork and canvas are adapted to the upper part1 and1 when the boat is on the sea1 it has the appearance of an ordinary canoe1 although1 as may be seen1 it differs essentially therefrom in the submerged part4 ,when the sea is heavy1 says ,mr4 ,relvas1 and the high waves are tumbling over each other1 they pass over my boat1 and are powerless to capsize it4 ,my boat clears waves that others are obliged to recoil before4 ,it has the advantage of being able to move forward1 whatever be the fury of the sea1 and is capable1 besides1 of approaching rocks without any danger of its being broken4 ,illustration3 ,,relvas',s ,,new ,,life ,,boat4 ,a committee was appointed by the ,portuguese government to examine this new life-boat1 and comparative experiments were made with it and an ordinary life-boat at ,porto on a very rough sea4 ,mr4 ,relvas's boat was manned by eight rowers all provided with cork girdles1 while the government life-boat was manned by twelve rowers and a pilot1 all likewise wearing cork girdles4 ,the chief of the maritime department1 an engineer of the ,portuguese navy and a ,portuguese deputy were present at the trial in a pilot boat4 ,the three boats proceeded to the entrance of the bar1 where the sea was roughest1 and numerous spectators collected upon the shore and wharfs followed their evolutions from afar4 ,the experiments began at half past three o'clock in the afternoon4 ,the two life-boats shot forward to seek the most furious waves1 and were seen from afar to surmount the billows and then suddenly disappear4 ,it was a spectacle as moving as it was curious4 ,it was observed that ,mr4 ,relvas's boat cleft the waves1 while the other floated upon their surface like a nut-shell4 ,after an hour's navigation the two boats returned to their starting point4 ,the official committee that presided over these experiments has again found in this new boat decided advantages1 and has pointed out to its inventor a few slight modifications that will render it still more efficient4--,la ,nature4 99 99 99 99 99 ,,experiments ,,with ,,double-,,barreled ,,guns ,,and ,,rifles4 ,the series of experiments we are about to describe has recently been made by ,mr4 ,horatio ,phillips1 a practical gun maker of ,london4 ,the results will no doubt prove of interest to those concerned in the use or manufacture of firearms4 ,the reason that the two barrels of a shot gun or rifle will1 if put together parallel1 throw their charges in diverging lines has never yet been satisfactorily accounted for1 although many plausible and ingenious theories have been advanced for the purpose4 ,the natural supposition would be that this divergence resulted from the axes of the barrels not being in the same vertical plane as the center line of the stock4 ,that this is not the true explanation of the fact1 the following experiment would tend to prove4 ,illustration3 ,,experiments ,,with ,,double-,,barrelled ,,guns4 ,fig4 #a represents a single barrel fitted with sights and firmly attached to a heavy block of beech4 ,this was placed on an ordinary rifle rest1 being fastened thereto by a pin at the corner1 ,a1 the block and barrel being free to revolve upon the pin as a center4 ,several shots were fired both with the pin in position and with it removed1 the barrel being carefully pointed at the target each time4 ,no practical difference in the accuracy of fire was discernible under either condition4 ,when the pin was holding the corner of the block1 the recoil caused the barrel to move from right to left in a circular path2 but when the pin was removed1 so that the block was not attached to the rest in any way1 the recoil took place in a line with the axis of the bore4 ,it will be observed that the conditions which are present when a double barreled gun is fired in the ordinary way from the shoulder were in some respects much exaggerated in the apparatus1 for the pin was a distance of #c in4 laterally from the axis of the barrel1 whereas the center of resistance of the stock of a gun against the shoulder would ordinarily be about one-sixth of this distance from the axis of the barrel4 ,this experiment would apparently tend to prove that the recoil does not appreciably affect the path of the projectile1 as it would seem that the latter must clear the muzzle before any considerable movement of the barrel takes place4 ,with a view to obtain a further confirmation of the result of this experiment1 it was repeated in a different form by a number of shots being fired from a cross-eyed rifle1#a in which the sights were fixed in the center of the rib4 ,very accurate shooting was obtained with this arm4 ,footnote #a3 ,a cross-eyed rifle is one made with a crooked stock for the purpose of shooting from the right shoulder1 aim being taken with the left eye4 ,a second theory1 often broached1 in order to account for the divergence of the charge1 is that the barrel which is not being fired1 by its vis inertia in some way causes the shot to diverge4 ,in order to test this1 ,mr4 ,phillips took a single rifle and secured it near the muzzle to a heavy block of metal1 when the accuracy of the shooting was in no way impaired4 ,so far the experiments were of a negative character1 and the next step was made with a view to discover the actual cause of the divergence referred to4 ,a single barrel was now taken1 to which a template was fitted1 in order to record its exact length4 ,the barrel was then subjected to a heavy internal hydrostatic pressure4 ,under this treatment it expanded circumferentially and at the same time was reduced in length4 ,this1 it was considered1 gave a clew to the solution of the problem4 ,a pair of barrels was now taken and a template fitted accurately to the side of the right-hand one4 ,as the template fitted the barrel when the latter was not subject to internal pressure1 upon such pressure being applied any alterations that might ensue in the length or contour of the barrel could be duly noted4 ,the right-hand barrel was then subjected to internal hydrostatic pressure4 ,the result is shown in an exaggerated form in ,fig4 #b4 ,it will be seen that both barrels are bent into an arched form4 ,this would be caused by the barrel under pressure becoming extended circumferentially1 and thereby reduced in length1 because the metal that is required to supply the increased circumference is taken to some extent from the length1 although the substance of metal in the walls of the barrel by its expansion contributes also to the increased diameter4 ,a simple illustration of this effect is supplied by subjecting an ,india-rubber tube to internal pressure4 ,supposing the material to be sufficiently elastic and the pressure strong enough1 the tube would ultimately assume a spherical form4 ,it is a well known fact that heavy barrels with light charges give less divergence than light barrels with heavy charges4 ,after the above experiments it was hoped that1 if a pair of barrels were put together parallel and soldered only for a space of #c in4 at the breech end1 and were then coupled by two encircling rings joined together as in ,fig4 #d1 the left-hand ring only being soldered to the barrel1 very accurate shooting would be obtained4 ,for1 it was argued1 that by these means the barrel under fire would be able to contract without affecting or being affected by the other barrel2 that on the right-hand1 it will be seen by the illustration1 was the one to slide in its ring4 ,a pair of able #j4ejj bore express rifle barrels were accordingly fitted in this way4 ,fig4 #c shows the arrangement with the rings in position4 ,upon firing these barrels with ordinary express charges it was found that the lines of fire from each barrel respectively crossed each other1 the bullet from the right-hand barrel striking the target #aj in4 to the left of the bull's eye1 while the left barrel placed its projectile a similar distance in the opposite direction2 or1 as would be technically said1 the barrels crossed #bj in4 at #ajj yards1 the latter distance being the range at which the experiment was made4 ,these last results have been accounted for in the following manner3 ,the two barrels were rigidly joined for a space of #c in41 and for that distance they would behave in a manner similar to that illustrated in ,fig4 #b1 and were they not coupled at the muzzles by the connecting rings they would shoot very wide1 the charges taking diverging courses4 ,when the connecting rings are fitted on1 the barrel not being fired will remain practically straight1 and1 as it is coupled to the barrel being fired by the rings1 the muzzle of the latter will be restrained from pointing outward4 ,the result will be as shown in an exaggerated manner by the dotted lines on the right barrel in ,fig4 #c4 ,it would appear from these experiments that when very accurate shooting is required at long ranges with double-barreled rifles1 they should be mounted in a manner similar to that adopted in the manufacture of the ,nordenfelt machine gun1 in which weapon the barrels are fitted into a plate at the extreme breech end1 the muzzles projecting through holes bored to receive them in a metal plate4 ,no unequal expansion would then take place1 and the barrels would be free to become shorter independently of each other4 ,we give the above experiments on the authority of their author1 who1 we believe1 has taken great pains to render them as exhaustive as possible1 so far as they go4--,engineering4 99 99 99 99 99 ,,ball ,,turning ,,machine4 ,the distinguishing feature in the ball turning machine shown opposite is that the tool is stationary1 while the work revolves in two directions simultaneously4 ,in the case of an ordinary spherical object1 such as brass clack ball1 the casting is made from a perfect pattern having two small caps or shanks1 in which the centers are also marked to avoid centering by hand4 ,it is fixed in the machine between two centers carried on a face plate or chuck1 with which they revolve4 ,one of these centers1 when the machine is in motion1 receives a continuous rotary motion about its axis from a wormwheel1 ,d4 ,this is driven by a worm1 ,c1 carried on a shaft at the back of the chuck1 and driven itself by a wormwheel1 ,b1 which gears with a screw which rides loosely upon the mandrel1 and is kept from rotating by a finger on the headstock4 ,this center1 in its rotation1 carries with it the ball1 which is thus slowly moved round an axis parallel to the face plate1 at the same time that it revolves about the axis of the mandrel1 the result being that the tool cuts upon the ball a scroll1 of which each convolution is approximately a circle1 and lies in a plane parallel to the line of centers4 ,when the chuck is set for one size of ball1 which may be done in a few minutes1 any quantity of that diameter may be turned without further adjustment4 ,a roughing cut for a #b in4 ball may be done in one minute1 and a finishing cut leaving the ball quite bright in the same time4 ,the two paps are cut off within one-sixteenth of an inch and then broken off1 and the ball finished in the usual way4 ,on account of the work being geometrically true1 the finishing by the ferrule tool is done in one quarter of the time usually required4 ,illustration3 ,,improved ,,ball ,,turning ,,machine4 ,the chuck may be applied to an ordinary lathe or may be combined with a special machine tool1 as show in our illustration4 ,in the latter case everything is arranged in the most handy way for rapid working1 and six brass balls of #b in4 in diameter can be turned and finished in an hour4 ,the machine is specially adapted for turning ball valves for pumps1 pulsometers1 and the like1 and in the larger sizes for turning governor balls and spherical nuts for armor plates1 and is manufactured by ,messrs4 ,wilkinson and ,lister1 of ,bradford ,road ,iron ,works1 ,keighley4--,engineering4 99 99 99 99 99 ,,cooling ,,apparatus ,,for ,,injection ,,water4 ,it often happens in towns and where manufactories are crowded together1 that the supply of water for condensing purposes is very small1 and consequently that it attains an inconveniently high temperature under unfavorable conditions of weather1 resulting in the deterioration of the vacuum and a consequent increase in the consumption of fuel4 ,to remedy or to diminish this difficulty1 ,messrs4 ,boase and ,miller1 of ,london1 have brought out the water cooler illustrated above4 ,this consists1 says ,engineering1 of a revolving basket of wire gauze surrounding an inner stationary vessel pierced with numerous small holes1 through which the heated water discharged by the air pump finds its way into the basket1 to be thrown out in the form of fine spray to a distance of #bj ft4 at each side4 ,the drops are received in the tank or pond1 and in their rapid passage through the air are sufficiently cooled to be again injected into the condenser4 ,the illustration shows a cooler having a basket three feet in diameter1 revolving at #cjj revolutions per minute1 and discharging into a tank #dj ft4 square4 ,it requires #c to #d indicated horse-power to drive it1 and will cool #cjj gallons per minute4 ,the following decrease of temperature has been observed in actual practice3 ,water entering at #ie deg4 fell #bj deg4 in temperature2 water entering at #ajj deg4 to #aaj deg4 fell #be deg42 and water entering at #aaj deg4 to #abj deg4 fell #cj deg4 ,the machine with which these trials were made was so placed that the top of the basket was four ft4 from the surface of the water in the pond4 ,with a greater elevation1 as shown in the engraving1 better results can be obtained4 ,illustration3 ,,improved ,,water ,,cooling ,,apparatus4 ,the advantages claimed for the cooler are that by its means the temperature of the injection water can be reduced1 the cost and size of cooling ponds can be diminished1 and condensing engines can be employed where hitherto they have not been possible4 ,the apparatus has been for two years in operation at several large factories1 and there is every reason to believe that its use will extend1 as it supplies a real want in a very simple and ingenious manner4 ,messrs4 ,duncan ,brothers1 of ,dundee and #cb ,queen ,victoria ,street1 ,e4,c41 are the manufacturers4 99 99 99 99 99 ,,corrugated ,,disk ,,pulleys4 ,this is a pulley recently introduced by ,messrs4 ,j4 and ,e4 ,hall1 of ,dartford ,eng4 ,with the exception of the boss1 which is cast1 it is composed entirely of steel or sheet iron4 ,in place of the usual arms a continuous web of corrugated sheet metal connects the boss to the rim2 this web is attached to the boss by means of ,spence's metal4 ,inside the rim1 which is flanged inward1 a double hoop iron ring is fixed for strengthening purposes4 ,the advantageous disposition of metal obtained by means of the corrugated web enables the pulley to be made of a given strength with less weight of material1 and from this cause and also on account of being accurately balanced these pulleys are well adapted for high speeds4 ,illustration 99 99 99 99 99 ,,kansas ,,city ,,review4 ,,early ,,history ,,of ,,the ,,telegraph4 ,although the electric telegraph is1 comparatively speaking1 a recent invention1 yet methods of communication at a distance1 by means of signals1 have probably existed in all ages and in all nations4 ,there is reason to believe that among the ,greeks a system of telegraphy was in use1 as the burning of ,troy was certainly known in ,greece very soon after it happened1 and before any person had returned from ,troy4 ,polybius names the different instruments used by the ancients for communicating information--pyrsia1 because the signals were always made by means of fire lights4 ,at first they communicated information of events in an imperfect manner1 but a new method was invented by ,cleoxenus1 which was much improved by ,polybius1 as he himself informs us1 and which may be described as follows3 ,take the letters of the alphabet and arrange them on a board in five columns1 each column containing five letters2 then the man who signals would hold up with his left hand a number of torches which would represent the number of the column from which the letter is to be taken1 and with his right hand a number of torches that will represent the particular letter in that column that is to be taken4 ,it is thus easy to understand how the letters of a short sentence are communicated from station to station as far as required4 ,this is the pyrsia or telegraph of ,polybius4 ,it seems that the ,romans had a method of telegraphing in their walled cities1 either by a hollow formed in the masonry1 or by a tube fixed thereto so as to confine the sound1 in order to convey information to any part they liked4 ,this method of communicating is in the present age frequently employed in the well known speaking tubes4 ,it does not appear that the moderns had thought of such a thing as a telegraph until #affa1 when the ,marquis of ,worcester1 in his ,century of ,inventions1 affirmed that he had discovered a method by which a man could hold discourse with his correspondent as far as they could reach1 by night as well as by day2 he did not1 however1 describe this invention4 ,dr4 ,hooke delivered a discourse before the ,royal ,society in #afhd1 showing how to communicate at great distances4 ,in this discourse he asserts the possibility of conveying intelligence from one place to another at a distance of #abj miles as rapidly as a man can write what he would have sent4 ,he takes to his aid the then recent invention of the telescope1 and explains how characters exposed at one station on the top of one hill may be made visible to the next station on the top of the next hill4 ,he invented twenty-four simple characters1 each formed of a combination of three deal boards1 each character representing a letter by the use of cords2 these characters were pushed from behind a screen and exposed1 and then withdrawn behind the screen again4 ,it was not1 however1 until the ,french revolution that the telegraph was applied to practical purposes2 but about the end of #agjc telegraphic communication was established between ,paris and the frontiers1 and shortly afterward telegraphs were introduced into ,england4 ,the history of the invention and introduction of the electric telegraph by ,prof4 ,morse is one of inexhaustible interest1 and every incident relating to it is worthy of preservation4 ,the incidents described below will be found of special interest4 ,the article is from the pen of the late ,judge ,neilson ,poe1 and was the last paper written by him4 ,he prepared it during his recent illness1 the letter embodied in it from ,mr4 ,latrobe being of course obtained at the time of its date4 ,it is as follows3 ,on the #eth of ,april1 #ahdc1 when the monthly meeting of the directors of the ,baltimore ,ohio ,railroad ,company was about to adjourn1 the ,president1 the ,hon4 ,louis ,mc,lane1 rose with a paper in his hand which he said he had almost overlooked1 and which the ,secretary would read4 ,it proved to be an application from ,prof4 ,morse for the privilege of laying the wires of his electric telegraph along the line of the railroad between ,baltimore and ,washington1 and was accompanied by a communication from ,b4,h4 ,latrobe1 ,esq41 ,chief ,engineer1 recommending the project as worthy of encouragement4 ,on motion of ,john ,spear ,nicholas1 seconded by the ,hon4 ,john ,p4 ,kennedy1 the following resolution was then considered3 ,resolved1 ,that the ,president be authorized to afford ,mr4 ,morse such facilities as may be requisite to give his invention a proper trial upon the ,washington road1 provided in his opinion and in that of the engineer it can be done without injury to the road and without embarrassment to the operations of the company1 and provided ,mr4 ,morse will concede to the company the use of the telegraph upon the road without expense1 and reserving to the company the right of discontinuing the use if1 upon experiment1 it should prove in any manner injurious4 ,whatever1 said ,mr4 ,mc,lane1 may be our individual opinions as to the feasibility of ,mr4 ,morse's invention1 it seems to me that it is our duty to concede to him the privilege he asks1 and to lend him all the aid in our power1 especially as the resolution carefully protects the company against all present or future injury to its works1 and secures us the right of requiring its removal at any time4 ,in view of the fact that no railroad can now be run safely without the aid of the telegraph1 the cautious care with which the right to remove it if it should become a nuisance was reserved1 strikes one at this day as nearly ludicrous4 ,a short pause ensued1 and the assent of the company was about to be assumed1 when one of the older directors1 famed for the vigilance with which he watched even the most trivial measure1 begged to be heard4 ,he admitted that the rights and interests of the work were all carefully guarded by the terms of the resolution1 and that the company was not called upon to lay out any of its means for the promotion of the scheme4 ,but notwithstanding all this1 he did not feel1 as a conscientious man1 that he could1 without further examination1 give his vote for the resolution4 ,he knew that this idea of ,mr4 ,morse1 however plausible it might appear to theorists and dreamers1 and so-called men of science1 was regarded by all practical people as destined1 like many other similar projects1 to certain failure1 and must consequently result in loss and possibly ruin to ,mr4 ,morse4 ,for one1 he felt conscientiously scrupulous in giving a vote which would aid or tempt a visionary enthusiast to ruin himself4 ,fortunately1 the views of this cautious1 practical man did not prevail4 ,a few words from the mover of the resolution1 ,mr4 ,nicholas1 who still lives to behold the wonders he helped to create1 and from ,mr4 ,kennedy1 without whose aid the appropriation would not have passed the ,house of ,representatives1 relieved the other directors from all fear of contributing to ,mr4 ,morse's ruin1 and the resolution was adopted4 ,of the ,president and thirty directors who took part in this transaction1 only three1 ,samuel ,w4 ,smith1 ,john ,spear ,nicholas1 and the writer1 survive4 ,under it ,morse at once entered upon that test of his invention whose fruits are now enjoyed by the people of all the continents4 ,it was not1 however1 until the spring of #ahdd that he had his line and its appointments in such a condition as to allow the transmission of messages between the two cities1 and it was in ,may of that year that the incident occurred which has chiefly led to the writing of this paper4 ,,mr4 ,,latrobe',s ,,recollections4 ,,my ,,dear ,,mr4 ,,poe3 ,agreeably to my promise1 this morning ,i put on paper my recollection of the introduction of the magnetic telegraph between ,baltimore and ,washington4 ,i was counsel of the ,baltimore ,ohio ,railroad ,co4 at the time1 and calling on ,mr4 ,louis ,mc,lane1 the ,president1 on some professional matter1 was asked in the course of conversation whether ,i knew anything about an electric telegraph which the inventor1 who had obtained an appropriation from ,congress1 wanted to lay down on the ,washington branch of the road4 ,he said he expected ,mr4 ,morse1 the inventor1 to call on him1 when he would introduce me to him1 and would be glad if ,i took an opportunity to go over the subject with him and afterward let him1 ,mr4 ,mc,lane1 know what ,i thought about it4 ,while we were yet speaking1 ,mr4 ,morse made his appearance1 and when ,mr4 ,mc,lane introduced me he referred to the fact that1 as ,i had been educated at ,west ,point1 ,i might the more readily understand the scientific bearings of ,mr4 ,morse's invention4 ,the ,president's office being no place for prolonged conversation1 it was agreed that ,mr4 ,morse should take tea at my dwelling1 when we would go over the whole subject4 ,we met accordingly1 and it was late in the night before we parted4 ,mr4 ,morse went over the history of his invention from the beginning with an interest and enthusiasm that had survived the wearying toil of an application to ,congress1 and with the aid of diagrams drawn on the instant made me master of the matter1 and wrote for me the telegraphic alphabet which is still in use over the world4 ,not a small part of what ,mr4 ,morse said on this occasion had reference to the future of his invention1 its influence upon communities and individuals1 and ,i remember regarding as the wild speculations of an active imagination what he prophesied in this connection1 and which ,i have lived to see even more than realized4 ,nor was his conversation confined to his invention4 ,a distinguished artist1 an educated gentleman1 an observant traveler1 it was delightful to hear him talk1 and at this late day ,i recall few more pleasant evenings than the only one ,i passed in his company4 ,of course1 my first visit the next morning was to ,mr4 ,mc,lane to make my report4 ,by this time ,i had become almost as enthusiastic as ,mr4 ,morse himself1 and repeated what had passed between us4 ,i soon saw that ,mr4 ,mc,lane was becoming as eager for the construction of the line to ,washington as ,mr4 ,morse could desire4 ,he entered warmly into the spirit of the thing1 and laughed heartily1 if not incredulously1 when ,i told him that although he had been ,minister to ,england1 ,secretary of ,state1 and ,secretary of the ,treasury1 his name would be forgotten1 while that of ,morse would never cease to be remembered with gratitude and praise4 ,we then considered the question as to the right of the company to permit the line to be laid in the bed of the road--the plan of construction at that time being to bury in a trench some eight or ten inches deep a half inch leaden tube containing the wrapped wire that was to form the electric circuit4 ,about this there was1 in my opinion1 no doubt1 and it was not long after that the work of construction commenced4 ,i met ,mr4 ,morse from time to time while he lived1 and often recurred to the evening's discussion at my house in ,baltimore4 ,the above is the substance of what ,i have more than once related to other persons4 ,i hope you will persist in your design of putting on paper your own very interesting recollections in this connection1 and if what ,i have contributed of mine is of service to you1 ,i shall be much pleased4 ,most truly yours1 ,,john ,h4,b4 ,,latrobe4 ,march #c1 #ahha4 99 99 99 99 99 ,,the ,,kravogl ,,electric ,,motor4 ,at the origin of every science1 of whatever nature it may be1 there is always a fruitless period1 of greater or less length1 characterized by the warfare of a few superior minds against general apathy4 ,the finest discoveries pass unperceived1 so to speak1 since they cannot cross the limits of a narrow circle2 and it often happens that they fall into oblivion before they have been seriously judged4 ,meanwhile1 a slow progress is imperceptibly made1 and1 in measure as theoretical principles more clearly disengage themselves1 a few industrial applications spring up and have the effect of awakening curiosity4 ,an impulse is thus given1 and from this moment a movement in advance goes on increasing at a headlong pace from day to day4 ,with electricity this period has been of comparatively short duration1 since scarcely a century and a half separate us from the first experiments made in this line of research4 ,now that it has truly taken its place in a rank with the other sciences1 we like to go back to the hesitations of the first hour1 and trace1 step by step1 the history of the progress made1 so as to assign to each one that portion of the merit that belongs to him in the common work4 ,when we thus cast a retrospective glance we find ourselves in the presence of one strange fact1 and that is the simultaneousness of discoveries4 ,that an absolutely original idea1 fertile in practical consequences1 should rise at a given moment in a fine brain is well2 we admire the discovery1 and1 in spite of us1 a little surprise mingles with our admiration4 ,but is it not a truly curious thing that several individuals should have had at nearly the same time that idea that was so astonishing in one8 ,this1 however1 is a fact that the history of electrical inventions offers more than one example of4 ,no one ignores the fact that the invention of the telephone gave rise to a notorious lawsuit1 two inventors having had this ingenious apparatus patented on the same day and at nearly the same hour4 ,this is one example among a thousand4 ,in the history of dynamo-electric machines it is an equally delicate matter to fix upon the one to whom belongs the honor of having first clearly conceived the possibility of engendering continuous currents4 ,we do not wish to take up this debate nor to go over the history of the question again4 ,every one knows that the first continuous current electric generator whose form was practical is due to ,zenobius ,gramme1 and dates back to ,july1 #ahga1 an epoch at which appeared a memoir 7entitled ,note upon a magneto-electric machine that produces continuous currents7 that was read to the ,academy of ,sciences by ,mr4 ,jamin4 ,ten years previous1 ,pacinotti had had a glimpse of the phenomenon1 and of its practical realization1 but was unfortunately unable to appreciate the importance of his discovery and the benefit that might be reaped from it4 ,it is of slight consequence whether ,gramme knew of this experiment or not1 for the glory that attaches to his name could not be diminished for all that4 ,but an interesting fact that we propose to dwell upon now has recently been brought to light in an electrical review published at ,vienna4#a ,it results from documents whose authenticity cannot be doubted that1 as far back as #ahfg1 ,mr4 ,l4 ,pfaundler1 a professor at ,innsbruck1 very clearly announced the reversibility of a magneto-electric motor constructed by ,kravogl1 a mechanician of the same place1 and that he succeeded some time before ,gramme in obtaining continuous currents4 ,footnote #a3 ,zeitschrift des ,electrotechnischen ,vereines in ,wien1 ,july1 #ahhc4 ,the ,kravogl motor that figured at the ,universal ,exhibition of #ahfg is but little known1 and it is now very difficult to obtain drawings of it4 ,what is certain is that this motor is an application of the properties of the solenoid1 and1 from this standpoint1 resembles the ,bessolo motor that was patented in #ahee4 ,we may figure the apparatus to our mind very well if we suppose that in the ,gramme ring a half and almost two-thirds of the core are removed1 and the spirals are movable around the said core4 ,if a current be sent into a portion of the spirals only1 and in such a way that only half of the core be exposed1 the latter will move with respect to the bobbin or the bobbin with respect to the core1 according as we suppose the solenoid or the bobbin fixed4 ,in the first case we have a ,bessolo motor1 and in the second a ,kravogl one4 ,in order to obtain a continuous motion it is only necessary to allow the current to circulate successively in the different portions of the solenoid4 ,it is difficult to keep the core in place1 since it is unreachable1 being placed in the interior of the bobbin4 ,kravogl solved this difficulty by constructing a hollow core into which he poured melted lead4 ,this heavy piece1 mounted upon rollers1 assumed a position of equilibrium that resulted from its weight1 from friction1 and from magnetic attraction4 ,but for a current of given intensity this position1 once reached1 did not vary1 and so necessitated a simple adjustment of the rubbers4 ,under such circumstances1 with a somewhat large number of sections1 the polarity of the core was nearly constant4 ,the spirals as a whole were attached to a soft iron armature that had the effect of closing up the lines of forces and forming a shell1 so to speak4 ,like ,bessolo1 ,kravogl never thought of making anything but a motor1 and did not perceive that his machine was reversible4 ,it results from some correspondence between ,dr4 ,a4 ,von ,waltenhofen and ,mr4 ,l4 ,pfaundler at this epoch that the latter clearly saw the possibility of utilizing this motor as a current generator4 ,under date of ,november #i1 #ahfg1 he wrote1 in speaking of the ,kravogl motor1 which had just been taken to ,innsbruck in order to send it to ,paris4 ,i regret that ,i shall not be able to see it any more1 for ,i should have liked to try to make it act in an opposite direction1 that is to say1 to produce a current or an electric light by means of mechanical work4 ,a little more than two years later these experiments were carried out on a larger motor constructed by ,kravogl in #ahfi1 and ,mr4 ,pfaundler was enabled to write as follows3 ,upon running the machine by hand we obtain a current whose energy is that of one ,bunsen element4 ,this letter is dated ,february #aa1 #ahgj1 that is to say1 it is a year anterior to the note of ,gramme4 ,illustration3 ,,fig4 #a4 ,in the presence of the historic interest that attaches to the question1 we do not think it will be out of place to reproduce here the considerations that guided ,prof4 ,pfaundler in the researches that led him to convert the ,kravogl motor into a dynamo-electric machine4 ,let us consider two magnetized bars1 db and bd'1 placed end to end and surrounded by a cylindrical armature forming a shell1 this armature being likewise supposed to be a permanent magnet and to present poles of contrary direction opposite the poles of the bars4 ,for the sake of greater simplicity this shell is represented by a part only in the figure1 s n n s4 ,if1 into a magnetic field thus formed1 we pass a spiral from left to right1 the spiral will be traversed by a current whose direction will change according to the way in which the moving is done4 ,it is only necessary to apply ,lenz's law to see that a reversal of the currents will occur at the points1 a and c1 the direction of the current being represented by arrows in the figure4 ,if we suppose a continual displacement of the spirals from left to right1 we shall collect a continuous current by placing two rubbers at a and c4 ,either the core or the shell may be replaced by a piece of soft iron4 ,in such a case this piece will move with the spiral and keep its poles that are developed by induction fixed in space4 ,from this1 in order to reach a dynamo-electric machine it is necessary to try to develop the energy of the magnetic field by the action of the current itself4 ,if we suppose the core to be of soft iron1 and make a closer study of the action of the current as regards the polarity that occurs under the influence of the poles1 s1 n1 s1 we shall see that from d to a and from b to c the current is contrary1 while that from a to b and from c to d' it is favorable to the development of such polarity4 ,in short1 with a spiral moving from d to d' the resulting effect is nil1 a fact1 moreover1 that is self-evident4 ,under such circumstances1 if we suppose the shell1 as well as the core1 to be of soft iron1 we shall obtain a feeble current due to the presence of remanent magnetism2 but this magnetism will not be able to continue increasing under the influence of the current4 ,to solve this difficulty two means present themselves3 7#a7 to cause a1 favorable magnetic current and act upon the armature1 and 7#b7 to suppress such portions of the current in the spirals as are injurious in effect4 ,the first solution was thought of by ,gramme in #ahga1 and is represented diagramatically in ,fig4 #b4 ,the second is due to ,prof4 ,pfaundler1 and dates back to #ahgj4 ,the core is cut through the center 7,fig4 #c71 and the portion to the right is suppressed2 the current is interrupted between da and cd'1 and is closed only between a and c 7v1 ,fig4 #a74 ,it results from this arrangement that1 under the action of the current1 the polarity due to remanent magnetism does nothing but increase4 ,it suffices then for but little remanent magnetism to prime the machine2 the polarity of the shell continues to increase1 and the energy of the magnetic field1 and consequently of the current1 has for a limit only the saturation of the soft iron4 ,if1 now1 we curve the core1 the spirals1 and the armature into a circle1 we have a ,gramme or a ,pfaundler machine1 according as we consider ,fig4 #b or ,fig4 #c4 ,illustration3 ,,fig4 #b4 ,illustration3 ,,fig4 #c4 ,this latter apparatus has in this case the form shown in ,fig4 #d4 ,illustration3 ,,fig4 #d4 ,the spiral1 s m b1 is movable1 and the core1 ,n o s1 is kept in a position of equilibrium by virtue of its weight1 and is provided with rollers4 ,for the sake of greater clearness1 the front part of the armature is supposed to be removed4 ,the current does not circulate in the spirals to the right of the diameter1 ,w ,o1 which latter is not absolutely vertical4 ,the position of the rubbers and armature is regulated once for all4 ,we do not know just what were the means devised by ,kravogl to suppress the current in the spheres to the right4 ,at all events1 it is probable that the system has grown old since ,gramme invented his collector4 ,in the application of the ,kravogl motor to the generation of continuous currents1 ,professor ,pfaundler now proposes to ingeniously utilize the ,gramme collector4 ,in such a case the arrangement shown in ,fig4 #e would be adopted4 ,let us suppose an ordinary collector having as many plates as there are sections in the ring1 these plates being connected as usual with the entrance and exit wires of the sections4 ,the diametrically opposite touches that are in the line1 ,w ,o1 are divided1 and one of the halves is connected at the entrance1 c a' 7,fig4 #d71 with the corresponding section1 while the other communicates with the exit1 c' a1 of the neighboring section4 ,each of these halves is prolonged by a piece of metal bent into the form of an arc of a circle and embracing a little less than a semi-circumference4 ,between these prolongations there is an insulating part4 ,in the rotary motion of the spiral1 at least one of the touches is always outside of the arc comprised between the brushes1 ,r4 ,in order to secure a continuity of the circuit in the effective arc1 ,w ,s o1 it is only necessary to arrange a rubber1 ,m1 in such a way as to establish a communication between the two parts of the divided touch as soon as this latter enters the arc under consideration4 ,in order to produce a current in the direction of the arrows shown in ,fig4 #d1 the spiral and axle must revolve from right to left4 ,in this case the rubber1 ,m1 occupies the position shown in the same figure1 the brushes embracing an arc of a little less than #ahj4 ,as soon as the lower touch comes in contact with the brush1 ,r1 when the revolution is being effected from left to right1 the rubber1 ,m1 establishes a communication between the two halves that have until now been isolated1 and the current is no longer interrupted4 ,the second touch during this time is at any point whatever of the arc1 ,w ,n o1 and the spirals corresponding to the latter arc outside of the circuit4 ,in short1 thanks to the rubber1 ,m1 we have an ordinary ,gramme collector in that portion of the circuit comprised between the brushes1 and a collector with a breakage of the circuit in the portion to the right4 ,illustration3 ,,fig4 #e4 ,this type of machine is entirely theoretical4 ,in the apparatus used for ,prof4 ,pfaundler's experiments in #ahgj1 the armature revolved with the solenoid4 ,the core and armature were of soft iron1 and the core was arranged in a manner analogous to the preceding1 and remained in place under the action of its weight1 and the shell1 forming a complete circle1 revolved with poles fixed in space4 ,practically1 the machine that we have just described would prove inconvenient to realize1 and would present serious inconveniences4 ,in the first place1 it seems to us quite difficult to transmit the motion of the solenoid to the axle1 supposing the former to revolve within the armature4 ,in the second place1 considerable friction would surely occur between the spirals and core1 and the axle1 being submitted to a lateral stress1 would be placed in a poor condition for work4 ,it is even allowable to doubt whether such a type could be practically got up4 ,at all events1 no trial has as yet been made of it4 ,compared with the ,gramme machine1 from an absolutely theoretical point of view1 the ,pfaundler apparatus presents undoubted advantages4 ,a theoretically perfect dynamo electric machine would be one in which there was a complete reciprocity between the magnetizing action of the current and the inductive action of the magnetic field4 ,now1 such is not the case in the ,gramme machine4 ,in this apparatus the soft iron core is at the same time a magnet through favorable induction and a disadvantageous electro-magnet4 ,this double polarization is only remedied to a certain extent by the adjustment of the brushes4 ,in the ,pfaundler machine1 on the contrary1 the electro-magnetism and magnetism through induction act in the same direction1 and concur in effecting a polarization that favors the production of the current4 ,looked at it in this light1 the latter machine more nearly approaches the type of perfection than does that of ,gramme4 ,but we must not forget that such qualities are purely theoretical4 ,in practice the best machine is that in which the copper is best utilized1 that is to say1 that which with a given weight of this metal furnishes the most work4 ,now1 this is certainly not the case in the ,pfaundler machine1 for here half or more than half of the ring is inert--a defect which is apparent at first sight4 ,it results from this that as soon as we propose to obtain an electromotive force1 however slight it be1 we must get it with machines of large dimensions4 ,now1 it is permissible to believe that under such circumstances 7taking into consideration the complication of mechanical means that the construction of such apparatus necessitates1 and the great friction that occurs7 it would be impossible to obtain practical rotary velocities4 ,comparing his machine with ,gramme's1 ,prof4 ,pfaundler expresses the idea that between them there is the same analogy as there is between a constant pressure and an expansion engine4 ,with cylinders of equal diameters the work performed by the former of these is greater than that done by the second1 but in the latter the expansive force of the steam is better utilized4 ,this comparison seems to us to be more ingenious than exact4 ,would it not be coming nearer to the truth if we were to suppose a case of a hydraulic motor whose performance continued diminishing with the height of the fall1 and would it not be advantageous under such circumstances to utilize only a portion of the fall for the purpose of increasing the motor's performance8 ,this machine1 however1 as before stated1 has never as yet been constructed1 so that experimental data relative to its mode of working are wanting4 ,it is especially interesting as regards its origin1 which dates back to an epoch at which researches on the dynamo electric machine were at their heat4 ,it is in its historical aspect that it is proper to regard it1 and it is from such a point of view that we have deemed it well to say a few words about it in this place4--,la ,lumiere ,electrique4 99 99 99 99 99 ,,bornhardt',s ,,electric ,,machine ,,for ,,blasting ,,in ,,mines4 ,we shall not attempt to pass in review the several apparatus that have hitherto been devised for igniting blasts in mining operations1 but shall simply describe in this place a machine recently invented for this purpose by ,mr4 ,bornhardt1 an engineer to the ,grand ,duke of ,brunswick4 ,this apparatus 7shown in the accompanying engravings7 consists essentially of two hard-rubber disks1 ,a 7,figs4 #b and #c71 keyed to an iron axle1 and of two rubbers1 ,b1 that are formed of skin and are held against the disks by small springs1 ,r2 motion is communicated to the axle1 a1 by means of a pair of gearings1 a and b1 and a crank1 f4 ,illustration3 ,,bornhardt',s ,,electric ,,machine ,,for ,,blasting ,,in ,,mines4 ,each disk revolves between two metallic rings1 c1 provided with points that attract and collect in ,leyden jars1 ,d1 the electricity produced by the friction4 ,for discharging the condensers there is employed a manipulator formed of a rod1 mm1 which can be acted upon1 from the exterior1 by means of a button1 k4 ,upon bringing the ball1 m1 of the rod in contact with the ball1 p1 of the condenser1 the lever 7which then takes the position shown by the dotted line7 continues to remain in connection with a small ring1 q1 through a special spring4 ,another ring1 t1 is connected in the same way with the external armature of the condenser4 ,upon connecting the rings1 p and t1 by a wire to which cartridges are attached1 any number of the latter may be ignited4 ,the parts that we have just enumerated are inclosed in a tin box covered with a wooden casing1 ,p4 ,between the two there is inserted a sheet of hard rubber in order to prevent a loss of electricity2 the whole is held in place by strong springs4 ,in order to show the normal state of the condenser1 a scale consisting of #ae metallic buttons to give the dimensions of the sparks1 is arranged at ,x4 ,this scale is capable of being connected with the rings1 q and t1 by means of chains2 when the spark obtained after #ae or #bj revolutions considerably exceeds the intervals of the scale1 it is a sure thing that the machine is in a proper state4 ,in order to prepare the apparatus for carriage1 the winch is taken off and placed in the compartment1 m1 which is closed by means of a door1 ,q4 ,figs4 #e and #f show the arrangement of the dynamite cartridges and wires in the blast hole4 ,figs4 #g to #aj show different arrangements of the igniting wires4 ,figs4 #aa and #ab give the general arrangement for igniting a number of cartridges simultaneously by means of the electric machine4 ,fig4 #ac shows the arrangement where powder is employed4 ,fig4 #ad shows the arrangement of a horizontal hole4--,annales ,industrielles4 99 99 99 99 99 ,,improved ,,electric ,,fire ,,alarm4 ,the object of this apparatus is to close an electric circuit when the temperature of a room rises above a certain point4 ,many devices have been invented for effecting this object1 each of which have their own advantages or disadvantages4 ,the invention of ,mr4 ,pritchett enables the required result to be obtained in a very satisfactory manner4 ,the apparatus consists 7as shown by the figure7 of a long glass vessel containing air2 connected to this vessel there is a glass tube filled with mercury4 ,the whole is mounted on a metal cradle1 which turns on pivots4 ,according to the position which the glass vessel and its adjuncts occupy in the cradle 7this position being adjustable by means of a thumb-screw1 seen at the upper part of the cradle71 so will the same have a tendency to rock longitudinally over to one side or the other4 ,now1 if we suppose the position to be such that the right hand end of the glass vessel is depressed1 and the left hand end raised1 then if the vessel becomes subjected to an elevation of temperature1 the air inside the same will become expanded1 and the mercury column in the tube will be driven over to the left1 and will rise in the turned up end of the tube4 ,this will cause the left hand branch of the glass vessel1 and its attachments1 to become increased in weight1 while the right hand branch will become proportionally lighter2 the consequence of this will be that the vessel and its cradle will cant over1 and by falling on an electrical contact will close a circuit and sound an alarm4 ,it is obvious that the apparatus is equally well adapted for indicating a diminution as well as an increase of temperature1 for if the electrical contact be placed under the right hand portion of the cradle1 and the latter be adjusted so that in its normal position its left hand portion is depressed1 then when the glass vessel becomes cooled1 the air in it will contract1 and the mercury will fall in the turned-up portion of the tube before referred to1 and will rise in the limb connected to the vessel1 consequently the cradle and glass vessel will cant over in the reverse way to that which it did in the first case4 ,owing to the surface which the glass vessel exposes1 the air inside quickly responds to any external change of temperature1 consequently the apparatus is very sensitive4 ,another important feature is the fact that the cradle and vessel in canting over acquires a certain momentum1 and thus the contact made becomes very certain4 ,illustration3 ,,pritchett',s ,,electric ,,fire ,,alarm4 ,mr4 ,pritchett proposes that his apparatus shall give external evidence outside the house by ringing a gong1 and by dropping a semaphore arm released by an electromagnet4 ,he also proposes 7as has often been suggested7 that a water supply shall be automatically turned on4--,electrical ,review4 99 99 99 99 99 ,a ,,standard ,,thermopile4 ,dr4 ,g4 ,gore1 ,f4,r4,s41 has invented an improved thermopile for measuring small electromotive forces4 ,it consists of about #cjj pairs of horizontal1 slender1 parallel wires of iron and ,german silver1 the former being covered with cotton4 ,they are mounted on a wooden frame4 ,about #a in4 of the opposite ends of the wires are bent downward to a vertical position to enable them to dip into liquids at different temperatures contained in long narrow troughs2 the liquids being non-conductors1 such as melted paraffin for the hot junctions1 and the non-volatile petroleum1 known as thin machinery oil4 ,the electromotive force obtained varies with the temperature2 a pile of #bie pairs having a resistance of #ie4f ohms at #af deg4 ,cent4 gave with a difference of temperature of #ajj deg4 ,cent4 an electromotive force of #j4ggbi volts1 or with #acj deg4 ,cent4 an electromotive force of #a4jje volt4 ,each element1 therefore1 equaled #j4jjjjbfb volt for each degree ,cent4 difference of temperature4 ,on having been verified with a standard voltaic cell the apparatus becomes itself a standard1 especially for small electromotive forces4 ,it is capable of measuring the #a_/cdhfa part of a volt4 ,for higher electromotive forces than a volt1 several of these piles would have to be connected in series4 ,the fractional electromotive force is obtained by means of a sliding contact which cuts out so many pairs as is required4 99 99 99 99 99 ,,telephonic ,,transmission ,,without ,,receivers4 ,the annual meeting of the ,french ,society of ,physics1 the success of which is continually increasing1 took place this year in the salons of the ,observatory1 which were kindly placed at the ,society's disposal by ,admiral ,mouchez4 ,there were three consecutive sessions1 the one of ,tuesday1 ,april #ae1 being set apart for the members of the ,association1 the one of the #afth for the invited guests of ,admiral ,mouchez1 and that of the #agth for the invited guests of the ,society4 ,the salons were partially lighted by the ,siemens differential arc1 continuous current lamps1 and partially by the ,swan incandescent lamp supplied by a distributing machine that permitted of the lamps being lighted and extinguished at will without changing the normal operation of all the rest4 ,many apparatus figured at this exhibition1 but we shall on the present occasion merely call attention to those that presented a certain character of novelty or of originality4 ,among the apparatus that we shall reserve a description of for the present was ,messrs4 ,richard ,bros4' registering thermometer designed for the ,concarneau laboratory1 an instrument which1 when sunk at one mile from the coast1 and to a depth of #dj meters1 will give a diagram of the temperature of the ocean at that depth2 and ,mr4 ,hospitalier's continuous electrical indicators1 designed for making known from a distance such mechanical or physical phenomena as velocities1 levels1 temperatures1 pressures1 etc4 ,among the most important of the apparatus exhibited we must reckon ,mr4 ,cailletet's devices for liquefying gases1 and those of ,mr4 ,mascart for determining the ohm4 ,the results obtained by ,mr4 ,mascart 7which have been submitted to the ,committee on ,unities of the ,congress of ,electricians now in session at ,paris71 are sensibly concordant with those obtained independently in ,england by ,lord ,rayleigh4 ,everything leads to the hope1 then1 that a rapid and definite solution will be given of this important question of electric unities1 and that nothing further will prevent the international development of the ,c4,g4,s4 system4 ,mr4 ,jules ,duboscq made a number of very successful projections1 and we particularly remarked the peculiar experiment made in conjunction with ,mr4 ,parinaud1 that gave in projection two like spectra produced by the same prism1 and which1 through superposition1 were capable of increasing the intensity of the colors1 or1 on the contrary1 of reconstituting white light4 ,among the optical applications we may cite ,mr4 ,leon ,laurent's apparatus for controlling plane1 parallel1 perpendicular1 and oblique surfaces1 and magic mirrors obtained with an ordinary light2 ,mr4 ,s4,p4 ,thompson's apparatus for demonstrating the propagation of electro-magnetic waves in ether 7according to ,maxwell's theory71 as well as some new polarizing prisms2 and a mode of lighting the microscope 7presented by ,mr4 ,yvon71 that was quite analogous to the one employed more than a year ago by ,dr4 ,van ,heurck1 director of the ,botanical ,garden of ,anvers4 ,acoustics were represented by an electro-magnetic brake siren of ,mr4 ,bourbouze2 ,konig's apparatus for the synthesis of sounds2 and ,mr4 ,s4,p4 ,thompson's cymatograph--a pendulum apparatus for demonstrating the phenomena of beats4 ,it was electricity again that occupied the largest space in the programme of the session4 ,apparatus for teaching are assuming greater and greater importance every day1 and the exhibit of ,mr4 ,ducretet included a large number of the most interesting of these4 ,the house of ,breguet exhibited on a reduced scale the magnificent experiments of ,gaston ,plante1 wherein #cbj leaden wire secondary elements charged for quantity with #c ,daniell elements1 and afterward coupled for tension1 served to charge a rheostatic machine formed of #ej condensers coupled for quantity4 ,these latter1 coupled anew for tension1 furnished upon being discharged a spark due to a difference of potential of about #cb1jjj volts that presented all the characters of the spark produced by induction coils on the machines so improperly called static4 ,finally1 we may cite the apparatus arranged by ,mr4 ,s4,p4 ,thompson for studying the development of currents in magneto-electric machines4 ,the inventor studies the influence of the forms of the inductors and armatures of machines by means of an arrangement that allows him to change the rings or armatures at will and to take out the induced bobbins in order to sound every part of the magnetic field4 ,upon giving the armature an angular motion limited by two stops1 there develops a certain quantity of electricity that may be measured by causing it to traverse an appropriate ballistic galvanometer4 ,messrs4 ,deprez and ,d',arsonval's galvanometer answers very well for this purpose1 and its aperiodicity1 which causes it quickly to return to zero as soon as the induced current ceases1 permits of a large number of readings being taken within a very short space of time4 ,measuring apparatus were represented by a new and very elegant arrangement of ,sir ,william ,thomson's reflecting galvanometers1 due to ,mr4 ,j4 ,carpentier4 ,the mounting adopted by ,mr4 ,carpentier permits of an easy removal of the bobbins and of an instantaneous substitution therefor4 ,the galvanometric part1 composed of the needles and mirror1 therefore remains entirely free1 thus allowing of its being verified1 and making it convenient to attach the silken fiber4 ,mr4 ,carpentier has1 moreover1 adopted for all the minor apparatus a transparent celluloid scale which simplifies them1 facilitates observations1 and renders the use of reflection almost industrial4 ,we shall complete our enumeration of the measuring apparatus by citing ,ducretet's non-oscillating galvanometer1 ,sir ,william ,thomson's amperemeters1 voltameters1 ohmmeters1 and mhosmeters1 constructed and exhibited by ,breguet1 and a new aperiodic galvanoscope of ,mr4 ,maiche4 ,mr4 ,baudot exhibited the recent improvements that he has made in his multiplex printing telegraph1 and ,m4 ,boudet of ,paris showed a new system of telephone transmission by submarine cables4 ,illustration3 ,,fig4 #a4--;,,diagram ,,exhibiting ,,the ,,arrangement ,,for ,,telephonic ,,transmissions ,,without ,a ,,receiver4 ,finally1 we shall conclude our enumeration by referring to the curiosities4 ,the house of ,siemens exhibited a miniature electric railway actuated by a new model of ,reynier accumulators2 ,m4 ,maiche operated a system of musical telephonic auditions that differed only in detail from those instituted by ,mr4 ,ader at the exhibition of #ahha2 and ,mr4 ,hospitalier presented a new form of an experiment devised by ,mr4 ,giltay1 consisting of a telephonic transmission of sounds without the use of receivers4 ,mr4 ,giltay's experiment is nothing but ,mr4 ,dunand's speaking condenser without the condenser4 ,a glance at ,fig4 #a will show how things are arranged for the experiment4 ,the transmitting system comprises two distinct circuits1 viz43 7#a7 one formed of a pile1 ,p1 of #b or #c ,leclanche elements1 or of #a or #b small sized accumulators1 an ,ader microphane transmitter1 ,m1 and the inducting wire of a small induction coil1 ,b2 and 7#b7 the other formed of the induced wire of the coil1 ,b1 of a pile1 ,p'1 of #aj or #ab ,leclanche elements1 and of a line whose extremities terminate at ,r1 in two ordinary electro-medical handles4 ,with this arrangement the experiment performed is as follows3 ,when any one speaks or sings in front of the transmitter1 ,t1 while two persons1 ,a and ,b1 each having one hand gloved1 are holding the handles in the ungloved hand1 it is only necessary for ,a to place his gloved hand upon ,b's ear1 or for the latter to place his hand upon ,a's1 or for each to place his hand on the other's ear simultaneously1 in order that ,a or ,b1 or ,a and ,b simultaneously1 may hear a voice issuing from the glove4 ,under these circumstances1 ,mr4 ,giltay's experiment is explained like ,dunand's speaking condenser--the hand of ,a and the ear of ,b here constituting the armature of an elementary condenser in which the glove performs the role of dielectric4 ,upon repeating this experiment at the laboratory of the ,school of ,physics and ,industrial ,chemistry of ,paris1 it has been found that the glove maybe replaced by a sheet of plain or paraffined paper4 ,in this case1 when two persons are holding the handles1 and have their ears applied1 one against the other1 if a sheet of paper be interposed1 airs or words will be heard to proceed therefrom4 ,finally1 it has been found possible to entirely suppress the paper1 or dielectric1 and to hear directly1 by simply interposing the auditor or auditors in the circuit4 ,one of the most curious forms of the experiment is the one shown in ,fig4 #b4 ,here a third person1 ,c1 hears the hands of ,a and ,b speak when a circuit is formed by means of three persons1 ,a1 ,b1 and ,c1 the two former1 ,a and ,b1 each holding one of the wires of the circuit and applying his free hand to the ear of ,c4 ,although the experiment is one that requires entire silence1 and could not on that account be performed at the laboratory1 a sort of telephonic chain can be formed in which five or six persons may hear at the same time4 ,a1 putting his hand on the ear of ,b1 the latter putting his to that of ,c1 and so on up to the last person1 who closes the circuit by grasping one of the handles1 the other one being held by ,a4 ,illustration3 ,,experiment ,,on ,,telephonic ,,transmission ,,without ,,receiving ,,apparatus4 ,it is difficult in the present state of science to explain very clearly how these telephonic transmissions are effected without a receiver4 ,all that we can conclude from it so far is that the ear is an instrument of incomparable delicacy and of exquisite sensitiveness1 since it perceives vibrations in which the energy developer1 particularly in the telephonic chain1 is exceedingly feeble4 ,without any desire to seek an application for an experiment that is simply curious1 we yet believe that there is here a phenomenon of a nature to be studied by physicists4 ,discoveries in telephony and microphony have certainly opened up to science1 as regards both theory and practice1 new horizons that still promise other surprises for the future4 ,but to return to the observatory3 ,the success obtained by the exhibition of the ,french ,society of ,physics shows that these reunions respond to a genuine need--that of instructing in and popularizing science4 ,while warmly congratulating the organizers of these meetings1 we may express a wish that the good example set by the ,society of ,physics may be followed by other societies4 ,we are convinced in advance that an equal success awaits them4--,la ,nature4 99 99 99 99 99 ,,on ,,the ,,arrangement ,,of ,,ground ,,conductors4 ,in telegraphy1 as well as in the question of lightning rods1 attention has been but incidentally paid to the improvement of ground conductors1 and this point has not been the object of that careful study that has been bestowed upon the establishment of aerial lines4 ,it is only recently that the interest created by lightning rods has given rise to new forms of conductors differing from those formerly used4 ,the publications of the ,prussian ,academy of ,sciences of from #ahgf to #ahhj contain some information of special importance in regard to this4 ,it is stated therein that the effect of ground conductors may be notably increased by the division of the earth plates and the use of metallic rods1 without necessitating a greater output of material4 ,these facts1 however1 have not as yet been put to profit in practice for the reason1 perhaps1 that the considerations1 which have remained general1 have not at once permitted of obtaining forms what could be employed with perfect knowledge of the results4 ,this is what led ,mr4 ,ulbricht1 of ,dresden1 to make calculations for a few forms of conductors1 and to test their approximate values4 ,the results of these researches are printed in the ,elektrotechnischen ,zeitschrift for #ahhc 7p4 #ah74 ,illustration ,the equations found show1 in the first place1 that there exist three means of obtaining a considerable effect1 as regards the ground conductor1 with a slight expenditure of material3 ,the cylindrical electrode may be drawn out into the form of a bar or wire2 the plate may be rendered narrow1 and elongated in the form of a ribbon2 and1 besides1 the annular plate may be enlarged in lessening the metallic surface4 ,finally1 a short1 open cylinder with a vertical axis may be formed by curving a narrow plate or ribbon4 ,it is not necessary to see the formula to recognize the fact that this cylinder must behave like a ribbon and a flat ring4 ,the radius increasing1 and the surface remaining constant1 the resistance of the earth here likewise approaches zero4 ,as the resistance of the earth is inversely proportional to the diameter of the plates1 the zero resistance can also be reached by dividing a plate ad infinitum4 ,as the parts of the plate may be brought quite close to each other without perceptibly interfering with the action1 a network has finally been reached by a division carried very far1 yet limited1 and by connecting the parts with one another by conducting cylinders4 ,if we seek to determine what forms of ground conductors are efficient and economical under given conditions1 we shall have to begin by informing ourselves as to the choice of material to be used for the electrode1 and shall then have to ascertain whether putting it in the ground will or will not necessitate much outlay4 ,the most suitable material is copper1 which may be used with advantage1 in that it lasts pretty well underground1 and that the facility which it may be worked permits of easily giving it more appropriate forms than those that can be obtained with cast iron1 which is of itself less costly4 ,if the burying in the ground requires little or no labor1 as when there exist ponds1 rivers1 and wells1 or subterranean strata of water near the surface of the earth1 elongated forms of conductors will be employed1 such as the solid or hollow cylinder1 the wire1 the ribbon1 the narrow ring1 and the network4 ,plates approaching a square or circular shape are not advantageous4 ,but if the ground has to be dug deeply in order to sink the conductor1 the form of the electrode must be more condensed1 and selected in such a way that the necessary action may be obtained with a minimum output of copper and labor4 ,for great depths1 and when the ground will permit of boring1 an elongated and narrow cylinder will be used4 ,such a system1 however1 can only be employed when the cylinder is surrounded by spring water1 since1 without that1 an intimate contact with earth that is only moist1 cannot be obtained with certainty4 ,in earth that is only moist and for moderate depths1 preference may be given to an electrode laid down flat4 ,the digging necessary in this case is onerous1 it is true1 but it permits of very accurately determining the state of the earth beneath and of obtaining a very perfect adherence of the electrode therewith4 ,two forms1 the annular ribbon or the flat ring and the network1 present themselves1 according to calculations1 as a substitute for copper plates1 which are so expensive2 and these forms are satisfactory on condition that the labor of digging be not notably increased4 ,these forms should always have a diameter a little greater than that of the plate4 ,the flat ring and the network1 however1 offer one weak point1 which they possess in common with the plate1 and that is1 their dimensions cannot be easily adapted to the nature of the ground met with without a notable increase in the expense4 ,now1 if the ground should offer a conductivity less than what was anticipated1 and it were desired to increase the plate1 say by one-third1 it would be impossible to do so as a consequence of the closed form4 ,one important advantage is realized in this respect by combining the ring and the network in the form of a reticulated ring having a diameter of from #a to #a meters4 ,on cutting this ring at a given place and according to a certain radius we obtain the reticulated ribbon shown in the accompanying figure4 ,the thickness of the wires is #b4e mm41 and their weight is #j4dge kilo4 per meter4 ,l1 ,l1 and ,l are the points at which the conducting cable is soldered4 ,a reticulated ribbon of copper can be made in advance of any length whatever1 and1 according to local exigencies1 it may be easily curved and given the form of a flat or cylindrical ring of varying width4 ,even though the ribbon has already been cut for a ring of given diameter1 it may be still further enlarged by drawing it out and leaving a bit of the ring open1 so as to thus obtain a nearly corresponding diminution in the resistance4 ,such a resistance may be still further diminished by rendering the ring higher1 that is to say1 by employing an annular cylindrical form4 ,after assuring himself1 by experiments on a small scale1 that calculation and observation gave concordant results for the flat ring1 the author made an experiment on a larger scale with the annular network4 ,for practical reasons he employed for this purpose a copper wire #b4e mm4 in diameter1 which may be expected to last as long as one of iron plate #b mm4 in thickness4 ,calculation showed that in a ribbon #afj mm4 wide1 meshes #dj mm4 in breadth were advantageous and favorable as regards rigidity4 ,a reticulated ribbon like this1 #d meters in length1 was made and formed into a flat ring having an external diameter of #a4db m4 and an internal one of #a4aj m4 ,the resistance of this ring was found to be ,w #j4cdhe 7#a_/k71 and that of a plate one meter square1 ,w#j #j4cfh 7#a_/k74 ,as the conductivity of the earth is very variable1 and as we cannot have an absolute guarantee that the ramming will be uniform1 it seemed proper to make the measurements of the resistance by fixing the plate and the ring in succession to the lower surface of a small raft1 in such a way that the contact with the water should correspond as well as possible to the suppositions made for the calculation4 ,as a second ground conductor1 a system of water pipes was used1 and1 after this1 a lightning rod conductor1 etc4 ,repeated and varied experiments gave1 for the calculation of the values of the resistances1 equations so concordant that the following results may be considered very approximate4 ,the square plate had a resistance of #ce4e ,siemens units1 and the reticulated ring one of #cb4e4 ,from the first figure we deduce k #a_/ia4ab1 that is to say1 the specific conductivity of river-water is #a3iaabjjjj4 ,calculation1 then1 gives as the resistance of the earth in ,siemens units3 ,calculated4 ,observed4 ,square plate4 #cc4e #cc4e ,annular ring4 #ca4gf #cb4e ,these figures prove the accuracy of the calculations that had been made in an approximate way4 ,the experiments were performed upon the ,elba1 above ,dresden4 ,other experiments still had reference to the influence of immersion4 ,in order to diminish polarization1 only instantaneous currents from the measuring pile were employed4 ,it was to be supposed that the current of water through which the bubbles of gas were removed from the electrodes would not have permitted of a notable resistance of polarization4 ,later measurements1 made upon a ribbon buried1 like the plates1 in the earth1 gave likewise most favorable results4 ,as a result of these experiments1 the ,state railways of ,saxony have1 in such cases as were practicable1 introduced the annular network of copper4 ,there are some manufacturers1 too1 who seem desirous of adopting this system1 although it has hardly emerged from the period of experiment4 ,the pecuniary advantages that will result from an application of it ought1 it would seem1 to dispel a large proportion of the criticisms directed against the erection of lightning rods1 from the standpoint of expense1 and contribute to extend an arrangement which may be considered as a very happy one4 ,if we compare the square plate with the equivalent annular network1 constructed as above indicated1 and which should possess1 according to the author an external diameter of #a4bf m4 and of #c4de m41 we find that3 ,the square plate1 #a mm4 thick weighs #h4i kilos4 #b #ag4h ,the annular network #a4fd ,the cost of reticulated ribbon per meter amounts to about #d4d francs1 supposing it to be arranged as shown in the cut4 ,as term of comparison1 we may admit that the following forms are nearly the equivalent of a horizontal1 unburied plate one meter square4 ,length4 ,diameter4 ,vertical cylinder buried #a4dj m4 #j4ac m4 #a4hj m4 #j4jf m4 ,vertical bar #b4fj m4 #j4jac m4 ,horizontal bar #e4bj m4 #j4jac m4 ,horizontal flat ring #a4cb m4 in external diameter1 and #a4jh m4 internal4 ,horizontal network #a4ja m4 square1 and having meshes of the same size as those of the reticulated ribbon4 ,horizontal reticulated ribbon #c m4 in length and of the structure described4 ,horizontal annular ring #a4bf m4 in external diameter1 #j4id m4 internal4 ,in conclusion1 let us meet an objection that might be made to the accuracy of the hypotheses that serve as a base to the preceding calculations1 in cases where ground plates for lightning rods and not for telegraphs are concerned4 ,between the two ground plates of a telegraph line there is generally a distance such that the curves of the current undergo no deviation in the vicinity of one of the electrodes 7the only part important for integrations7 through the influence of the other4 ,but it might be admitted that such would prove the case with a lightning rod in a storm1 at the time of the passage of the fluid into the earth4 ,the ground plate here is one of the electrodes1 and the other is replaced by the surface of the earth strongly charged to a great distance under the storm clouds4 ,if we suppose 7what may be admitted in a good lightning rod7 that there no longer occurs any spark from the point downward1 the curves of the current1 in starting perpendicularly from the ground plate1 would be obliged to leave their rectilinear trajectory and strike the surface of the earth at right angles4 ,when the electricity flows through a plane surface into an infinite body1 it is only when such surface presents a very great development that the respective potentials decrease very slowly in the vicinity of the said surface4 ,no notable modification occurs1 then1 in the curves of equal potential1 in the vicinity of the ground plate through the action of this extended charge1 nor consequently any modification in the curves of the current2 but the electricity which spreads has but a short distance to travel in order to overcome the most important resistances4 ,the calculations of resistances given above have1 then1 the same value for discharges of atmospheric electricity4--,bull4 du ,musee de l',industrie4 99 99 99 99 99 ,,on ,,electrolysis4 ,by ,h4 ,,schucht4 ,concerning the separations which take place at the positive pole1 the composition of the peroxides1 and the manner of their determination1 relatively little has been done4 ,if solutions of the salts of lead1 thallium1 silver1 bismuth1 nickel1 and cobalt are decomposed by the current between platinum electrodes1 metal is deposited at the negative1 and oxide at the positive electrode4 ,manganese is precipitated only as peroxide4 ,the formation of peroxide is1 of course1 effected by the ozone found in the electrolytic oxygen at the positive pole2 the oxide existing in solution is brought to a higher degree of oxidation1 and is separated out4 ,its formation may be decreased or entirely prevented by the addition of readily oxidizible bodies1 such as organic acids1 lactose1 glycerine1 and preferably by an excess of oxalic acid2 but only until the organic matter is transformed into carbonic acid4 ,in this manner ,classen separates other metals from manganese in order to prevent the saline solutions from being retained by the peroxide4 ,with solutions of silver1 bismuth1 nickel1 and cobalt1 it is often practicable to prevent the separation of oxide by giving the current a greater resistance--increasing the distance between the electrodes4 ,the proportion between the quantities of metal and of peroxide deposited is not constant1 and even if we disregard the concentration of the solution1 the strength of the current and secondary influences 7action of nascent hydrogen7 is different in acid and in alkaline solutions4 ,in acid solutions much peroxide is formed2 in alkaline liquids1 little or none4 ,the reason of the difference is that ozone is evolved principally in acid solutions1 but appears in small quantities only in alkaline liquids1 or under certain circumstances not at all4 ,the quantity of peroxide deposited depends also on the temperature of the saline solution2 at ordinary temperatures the author obtained more peroxide--the solution1 the time1 and the strength of current being equal--than from a heated liquid4 ,the cause is that ozone is destroyed by heat and converted into ordinary oxygen4 ,with the exception of lead and thallium the quantity of metal deposited from an acid solution is always greater than that of the peroxide4 ,lead4--,luckow has shown that from acid solutions--no matter what may be the acid--lead is deposited at the anode as a mixture of anhydrous and hydrated peroxide of variable composition4 ,only very strongly acid solutions let all their lead fall down as peroxide2 the precipitation is rapid immediately on closing the circuit1 and complete separation is effected only in presence of at least #aj per cent4 of free nitric acid4 ,as the current becomes stronger with the increase of free acid1 there is deposited upon the first compact layer a new stratum of loosely adhering peroxide4 ,in presence of small quantities of other metals which are thrown down by the current in the metallic state1 such as copper1 mercury1 etc41 peroxide alone is deposited from a solution of lead containing small quantities only of free nitric acid4 ,the lead peroxide deposited is at first light brown or dark red1 and becomes constantly darker and finally taking a velvet-black4 ,as its stratification upon the platinum is unequal1 it forms beautifully colored rings4 ,experiments show that the quantity of peroxide deposited depends on the nature of the solution and the strength of the current4 ,in case of very feeble currents and slight acidity1 its quantity is so small that it does not need to be taken into consideration4 ,if the lead solution is very dilute scarcely any current is observed1 lead solutions per se being very bad conductors of electricity4 ,faintly acid concentrated lead solutions give loose peroxide along with much spongy metallic lead4 ,free alkali decreases the separation of peroxide2 feebly alkaline solutions1 concentrated and dilute1 yield relatively much peroxide along with metallic lead1 while strongly alkaline solutions deposit no peroxide4 ,dried lead peroxide is so sparingly hygroscopic that it may be weighed as such2 its weight remains constant upon the balance for a long time4 ,in order to apply the peroxide for quantitative determinations1 a large surface must be exposed to action4 ,as positive electrode a platinum capsule is convenient1 and a platinum disk as negative pole4 ,the capsule shape is necessary because the peroxide when deposited in large quantities adheres only partially1 and falls in part in thin loose scales4 ,it is necessary to siphon off the nitric solution1 since1 like all peroxides1 that of lead is not absolutely insoluble in nitric acid4 ,the methods of ,riche and ,may give results which are always too high1 since portions of saline solution are retained by the spongy deposit and can be but very imperfectly removed by washing4 ,this is especially the case in presence of free alkali4 ,the author has proceeded as follows3 ,the lead peroxide is dried in the capsule1 and there is passed over it pure dry gaseous sulphurous acid in a strong current from a rather narrow delivery tube4 ,lead sulphate is formed with evolution of heat2 it is let cool under the exsiccator1 and weighed as such4 ,or he ignites the peroxide along with finely pulverized ammonium sulphite2 the mass must have a pure white color4 ,after the conclusion of the reaction it is ignited for about #bj minutes4 ,the results are too high4 ,the proportion of actual lead peroxide in the deposit ranges from #id to #id4gf per cent4 ,the peroxide precipitated from a nitric solution may1 under certain circumstances1 be anhydrous4 ,this result is due to the secondary influences at the positive pole1 where the free acid gradually withdraws water from the peroxide4 ,the peroxide thrown down from alkaline solutions retains alkali so obstinately that it cannot be removed by washing2 the peroxide plays here the part of an acid4 ,the lead nitrate mechanically inclosed in the peroxide is resolved by ignition into oxide1 hyponitric acid1 and oxygen2 this small proportion of lead oxide does not exert an important influence on the final result4 ,the quantity of matter mechanically inclosed is relatively high1 as in the precipitation of much lead peroxide there is relatively more saline matter occluded than when a few centigrammes are deposited4 ,the peroxide incloses also more foreign matter if it is thrown down upon a small surface than if it is deposited in a thin layer over a broad surface4 ,from numerous analyses the author concludes that in presence of much free nitric acid the proportion of water is increased2 with free alkali the reverse holds good4 ,thallium behaves similarly to lead4 ,from a nitric acid solution it is thrown down1 according to the proportion of free acid1 either as sesquioxide only or in small quantities as silvery1 metallic leaflets2 from alkaline solutions it is deposited as sesquioxide and metal1 the latter of a lead-gray color4 ,thallium solutions conduct the electric current badly4 ,thallium oxide resembles lead peroxide in color2 at a strong heat it melts1 becomes darker1 and is converted into peroxide1 in which state it can be weighed4 ,silver4--,all solutions of silver salts1 except the nitrate1 and those containing a very large quantity of free nitric acid or nitrates1 deposit electrolytically merely metallic silver4 ,in the above mentioned exceptional cases there is formed a small quantity of peroxide which adheres to the anode as a blackish-gray deposit4 ,the greatest quantity of peroxide is obtained on employing a concentrated1 strongly acid solution of the nitrate1 and a strong current4 ,if the solution is very dilute we obtain no peroxide1 or mere traces which disappear again toward the end of the process4 ,the peroxide is deposited at first in small1 dark1 shining octahedral crystals2 subsequently1 in an amorphous state4 ,at #aaj it evolves oxygen suddenly1 and is converted into metallic silver4 ,it dissolves in ammonia with a violent escape of nitrogen4 ,in nitric acid it dissolves without decomposition and with a red color4 ,the author uses a galvanic current for reducing silver residues1 consisting of sulphocyanide4 ,the salt is mixed with sulphuric acid in a roomy platinum capsule1 and a fine platinum wire gauze is used as positive electrode4 ,bismuth4--,the current resolves bismuth solutions into metal and bismutic acid4 ,the latter is deposited at the positive pole1 and in thin layers appears of a golden-yellow1 but in thick strata is darker1 approaching to red4 ,its formation is very gradual1 and in time it disappears again1 owing to secondary actions of the current4 ,on ignition it becomes lemon yellow1 and transitorily darker1 even brown1 and passes into the sexquioxide4 ,nickel and ,cobalt4--,on the electrolysis of the ammonical solution the sesquioxide appears at the positive pole4 ,its formation is prevented by an excess of ammonia4 ,the author never obtains more than #c per cent4 of the quantity of the metal4 ,the sesquioxides dissolve in ammonia without escape of nitrogen1 and are usually anhydrous4 ,manganese4--,manganese is the only metal which is precipitated only as peroxide4 ,it is deposited at once on closing the circuit1 and is at first brown1 then black and shining4 ,organic acids1 ferrous oxide1 chromic oxide1 ammonium salts1 etc41 prevent the formation of peroxide and the red color produced by permanganic acid4 ,in very dilute strongly acid nitric solutions there is formed only permanganic acid1 which according to ,riche is plainly visible in solutions containing #a_/ajjjjjj grm4 manganese4 ,on electrolyzing a manganiferous solution of copper nitrate1 red permanganic acid appeared in a stratum floating above the platinum disk coated with brown peroxide4 ,no manganese peroxide was deposited4 ,the peroxide adheres firmly to the platinum when the proportion of free acid is small1 not exceeding #c per cent41 and the current is not too strong4 ,if the action of the current is prolonged after the peroxide is thrown down1 it falls off in lamin4 ,according to ,riche1 in a nitric solution the manganese is deposited as peroxide1 also at the negative pole4 ,this formation is not directly due to the current1 but is a precipitate occasioned by the production of ammonia by the reduction of nitric acid4 ,to determine the manganese in peroxide electrolytically precipitated1 it is heated to bright redness in the platinum capsule until the weight becomes constant4 ,the results are too high4 ,selenium and ,tellurium4--,both these bodies are readily and completely reduced by the current either in acid or alkaline solutions4 ,selenium is thrown down at first of a fine brownish red1 which gradually becomes darker4 ,the deposit of tellurium is of a bluish black color4 ,if the current is feeble1 the deposit of selenium is moderately compact2 that of tellurium is always loose1 and it often floats on the liquid4 ,a strong current precipitates both as powders4 ,the positive pole is coated during electrolysis with a film of a dark color in case of selenium1 but of a lemon yellow with tellurium4 ,as in case of arsenic and antimony1 the hydrogen evolved at the negative pole combines with the reduced substances1 forming hydrogen1 selenide1 or telluride1 which remain in part in solution in the liquid4 ,the reduced metal separates out at the anode in a friable condition4--,zeitschrift fur ,analytische ,chemie1 and ,chemical ,news4 99 99 99 99 99 ,,the ,,electro-,,chemical ,,equivalent ,,of ,,silver4 ,a very careful and important determination of the electrochemical equivalent of silver has been made at the observatory of the ,physical ,institute of ,wrzbourg1 and the results are that an ampere current flowing for a second1 or a coulomb of electricity deposits #a4aahc milligrammes of silver or #j4cbha milligramme of copper1 and decomposes #j4jicbh milligramme of water1 a result agreeing closely with that of ,lord ,rayleigh recently communicated to the ,physical ,society4 ,an ampere therefore deposits #d4jbei grammes of silver per hour2 ,kohlrausch's value is #d4jhbd1 a value hitherto accepted universally4 ,this value is so useful in measuring electric currents with accuracy1 and free from the disturbances of magnetism1 etc41 that it is eminently satisfactory to find the ,german value agree with that of ,lord ,rayleigh1 which will probably be adopted by ,english electricians4 99 99 99 99 99 ,a ,,new ,,standard ,,light4 ,herr ,hefner-,alteneck has suggested a new standard light for photometric purposes1 which promises to be very simple and effective in operation4 ,the light is produced by an open flame of amyl-acetate burning from a wick of cotton fiber which fills a tube of ,german silver #a in4 long and #caf mils4 internal diameter2 the external diameter being #cbd mils4 ,the flame is #a4eh in4 high from top to bottom2 and it should be lighted at least ten minutes before using the light for testing4 ,a cylindrical glass chimney surrounds it to ward off air currents4 ,about #b per cent4 of the light is absorbed by the glass4 ,the power of the flame is that of a standard ,english candle2 and experiments have shown that amyl acetate1 which besides is not expensive1 is the best fuel for steadiness and brilliance4 ,neither the substitution of commercial amyl-acetate for pure nor the use of a wick of cotton thread for loose cotton fiber alters the illuminating power2 but the wick should be trimmed square across the mouth of the tube1 for if it project and droop the illuminating power is increased4 99 99 99 99 99 ,,nature4 ,,dr4 ,,feussner',s ,,new ,,polarizing ,,prism4 ,in a recent number of the ,zeitschrift fur ,instrumentenkunde 7iv41 #db-ej1 ,february1 #ahhd71 ,dr4 ,k4 ,feussner of ,karlsruhe has given a detailed description of a polarizing prism lately devised by him1 which presents several points of novelty1 and for which certain advantages are claimed4 ,the paper also contains an account1 although not an exhaustive one1 of the various polarizing prisms which have from time to time been constructed by means of different combinations of ,iceland spar4 ,the literature of this subject is scattered and somewhat difficult of access1 and moreover only a small part of it has hitherto been translated into ,english2 and it would appear therefore that a brief abstract of the paper may not be without service to those among the readers of ,nature who may be unacquainted with the original memoirs1 or who may not have the necessary references at hand4 ,following the order adopted by ,dr4 ,feussner1 the subject may be divided into two parts3 ,i4--,,older ,,forms ,,of ,,polarizing ,,prisms4 ,in comparing the various forms of polarizing prisms1 the main points which need attention are--the angular extent of the field of view1 the direction of the emergent polarized ray1 whether it is shifted to one side of1 or remains symmetrical to the long axis of the prism2 the proportion which the length of the prism bears to its breadth2 and lastly1 the position of the terminal faces1 whether perpendicular or inclined to the long axis4 ,these requirements are fulfilled in different degrees by the following methods of construction3 ,illustration3 ,fig4 #a41 ,fig4 #b41 and ,fig4 #c4 #a4 ,the ,nicol ,prism 7,edin4 ,new ,phil4 ,journal1 #ahbh1 vi41 #hc74--,this 7,fig4 #a71 as is well known1 is constructed from a rhombohedron of ,iceland spar1 the length of which must be fully three times as great as the width4 ,the end faces are cut off in such a manner that the angle of #gb which they originally form with the lateral edge of the rhombohedron is reduced to #fh4 ,the prism is then cut in two in a plane perpendicular to the new end surfaces1 the section being carried obliquely from one obtuse corner of the prism to the other1 in the direction of its length4 ,the surfaces of this section1 after having been carefully polished1 are cemented together again by means of ,canada balsam4 ,a ray of light1 on entering the prism1 is separated by the double refraction of the calc-spar into an ordinary and an extraordinary ray2 the former undergoes total reflection at the layer of balsam at an incidence which allows the extraordinary ray to be transmitted2 the latter1 therefore1 passes through unchanged4 ,this principle of obtaining a single polarized ray by means of total reflection of the other is common to all the forms of prism now to be described4 ,dr4 ,feussner gives a mathematical analysis of the paths taken by the two polarized rays within the ,nicol prism1 and finds that the emergent extraordinary ray can include an angular field of #bi1 but that this extreme value holds good only for rays incident upon that portion of the end surface which is near to the obtuse corner1 and that from thence it gradually decreases until the field includes an angle of only about half the previous amount4 ,he finds1 moreover1 that1 although of course the ray emerges parallel to its direction of incidence1 yet that the zone of polarized light is shifted to one side of the central line4 ,also that the great length of the ,nicol--#c4bh times its breadth--is not only an inconvenience1 but owing to the large pieces of spar thus required for its construction1 prisms of any but small size become very expensive4 ,to this it may be added that there is a considerable loss of light by reflection from the first surface1 owing to its inclined position in regard to the long axis of the prism4 ,illustration3 ,fig4 #d41 ,fig4 #e41 and ,fig4 #f4 ,it is with the view of obviating these defects that the modifications represented in ,figs4 #b to #f have been devised4 #b4 ,the ,shortened ,nicol ,prism4--,this arrangement of the ,nicol prism is constructed by ,dr4 ,steeg and ,reuter of ,homburg v4d4,h4 ,for the sake of facility of manufacture1 the end surfaces are cleavage planes1 and the oblique cut1 instead of being perpendicular1 makes with these an angle of about #hd4 ,by this alteration the prism becomes shorter1 and is now only #b4hc times its breadth2 but if ,canada balsam is still used as the cement1 the field will occupy a very unsymmetrical position in regard to the long axis4 ,if balsam of copaiba is made use of1 the index of refraction of which is #a4ej1 a symmetrical field of about #bd will be obtained4 ,a prism of this kind has also been designed by ,prof4 ,b4 ,hasert of ,eisenach 7,pogg4 ,ann41 cxiii41 #ahi71 but its performance appears to be inferior to the above4 #c4 ,the ,nicol ,prism with ,perpendicular ,ends4--,the terminal surfaces in this prism are perpendicular to the long axis1 and the sectional cut makes with them an angle of about #ge4 ,the length of the prism is #c4ge times its breadth1 and if the cement has an index of refraction of #a4ebe1 the field is symmetrically disposed1 and includes an angle of #bg4 ,prisms of this kind have been manufactured by ,dr4 ,steeg1 ,mr4 ,c4,d4 ,ahrens1 and others4 #d4 ,the ,foucault ,prism 7,comptes ,rendus1 #aheg1 xlv41 #bch74--,this construction differs from all those hitherto mentioned1 in that a film of air is employed between the two cut surfaces as the totally reflecting medium instead of a layer of cement4 ,the two halves of the prism are kept in position1 without touching each other1 by means of the mounting4 ,the length of the prism is in this way much reduced1 and amounts to only #a4ebh times its breadth4 ,the end surfaces are cleavage planes1 and the sectional cut makes with them an angle of #ei4 ,the field1 however1 includes not more than about #h1 so that this prism can be used only in the case of nearly parallel rays2 and in addition to this the pictures which may be seen through it are to some extent veiled and indistinct1 owing to repeated internal reflection4 #e4 ,the ,hartnack ,prism 7,ann4 de ,ch4 et de ,physique1 ser4 iv41 vii41 #aha74--,this form of prism was devised in #ahff by ,,mm4 ,hartnack and ,prazmowiski2 the original memoir is a valuable one2 a translation of it1 with some additions1 has lately been published 7,journ4 of the ,r4 ,microscopical ,soc41 ,june1 #ahhc1 #dbh74 ,it is considered by ,dr4 ,feussner to be the most perfect prism capable of being prepared from calc-spar4 ,the ends of the prism are perpendicular to its length2 the section carried through it is in a plane perpendicular to the principal axis of the crystal4 ,the cementing medium is linseed oil1 the index of refraction of which is #a4dhe4 ,this form of prism is certainly not so well known in this country as it deserves to be2 a very excellent one1 supplied to the present writer by ,dr4 ,steeg is of rectangular form throughout1 the terminal surfaces are #ai #ae mm41 and the length #da mm4 ,the lateral shifting of the field is scarcely perceptible1 the prism is perfectly colorless and transparent1 and its performance is far superior to that of the ordinary ,nicol4 ,the field of view afforded by this construction depends upon the cementing substance used1 and also upon the inclination of the sectional cut in regard to the end of the prism2 it may vary from #bj to #da4 ,if the utmost extent of field is not required1 the prism may be shortened by lessening the angle of the section1 at the expense1 however1 of interfering with the symmetrical disposition of the field4 #f4 ,the ,glan ,prism 7,carl's ,repertorium1 xvi41 #egj1 and xvii41 #aie74--,this is a modification of the ,foucault1 and in a similar manner includes a film of air between the sectional surfaces4 ,the end surfaces and also the cut carried through the prism are parallel to the principal axis of the calc-spar4 ,the ends are normal to the length1 and the field includes about #h4 ,this prism is very short1 and may indeed be even shorter than it is broad4 ,it is subject to the same defect as that mentioned in the case of the ,foucault1 although perhaps not quite to the same extent4 ,,ii4--,,the ,,new ,,polarizing ,,prism4 ,this prism differs very considerably from the preceding forms1 and consists of a thin plate of a doubly refracting crystal cemented between two wedge-shaped pieces of glass1 the terminal faces of which are normal to the length4 ,the external form of the prism may thus be similar to the ,hartnack1 the calc-spar being replaced by glass4 ,the indices of refraction of the glass and of the cementing medium should correspond with the greater index of refraction of the crystal1 and the directions of greatest and least elasticity in the latter must stand in a plane perpendicular to the direction of the section4 ,one of the advantages claimed for the new prism is that1 it dispenses with the large and valuable pieces of spar hitherto found necessary2 a further advantage being that other crystalline substances may be used in this prism instead of calc-spar4 ,the latter advantage1 however1 occurs only when the difference between the indices of refraction for the ordinary and extraordinary rays in the particular crystal made use of is greater than in calc-spar4 ,when this is the case1 the field becomes enlarged1 and the length of the prism is reduced4 ,illustration3 ,fig4 #g4 ,the substance which ,dr4 ,feussner has employed as being most suitable for the separating crystal plate is nitrate of soda 7natronsalpeter71 in which the above-mentioned values are omega #a4ehg and eta #a4ccf4 ,it crystallizes in similar form to calcite1 and in both cases thin plates obtained by cleavage may be used4 ,as the cementing substance for the nitrate of soda1 a mixture of gum dammar with monobromonaphthalene was used1 which afforded an index of refraction of #a4eh4 ,in the case of thin plates of calcite1 a solid cementing substance of sufficiently high refractive power was not available1 and a fluid medium was therefore employed4 ,for this purpose the whole prism was inclosed in a short glass tube with airtight ends1 which was filled with monobromonaphthalene4 ,in an experimental prism a mixture of balsam of tolu was made use of1 giving a cement with an index of refraction of #a4fb1 but the low refractive power resulted in a very considerable reduction of the field4 ,the extent and disposition of the field may be varied by altering the inclination at which the crystal lamina is inserted 7,fig4 #g71 and thereby reducing the length of the prism1 as in the case of the ,hartnack4 ,in order to obviate the effects of reflection from the internal side surfaces if the prism1 the wedge-shaped blocks of glass of which it is built up may be made much broader than would otherwise be necessary2 the edges of this extra width are cut obliquely and suitably blackened4 ,the accompanying diagram 7,fig4 #h7 represents a prism of cylindrical external form constructed in this manner1 the lower surface being that of the incident light4 ,in this the field amounts to #cj1 and the breadth is about double the length4 ,illustration3 ,fig4 #h4 ,dr4 ,feussner remarks that a prism similar in some respects to his new arrangement was devised in #ahfi by ,m4 ,jamin 7,comptes ,rendus1 lxviii41 #bba71 who used a thin plate of calc-spar inclosed in a cell filled with bisulphide of carbon2 and also by ,dr4 ,zenker1 who replaced the liquid in ,m4 ,jamin's construction by wedges of flint glass4 ,among others1 the carefully considered modifications of the ,nicol prism which have recently been devised by ,prof4 ,s4,p4 ,thompson 7,phil4 ,mag41 ,november1 #ahha1 #cdi1 and ,jour4 ,r4 ,micros4 ,soc41 ,august1 #ahhc1 #ege71 and by ,mr4 ,r4,t4 ,glazebrook 7,phil4 ,mag41 ,may1 #ahhc1 #ceb71 do not appear to have been known to ,dr4 ,feussner4 ,the following tabular view of different forms of polarizing prisms is taken from the conclusion of ,dr4 ,feussner's paper3 ---------------------------------------- -------------------------- ,inclina- ,ratio tion of of section length in regard to to long clear ,field4axis4 width4,fig4 ---------------------------------------- -------------------------- ,i4 ,,the ,,old ,,polarising ,,prisms4 #a4 ,nicol's prism4 #bi #bb #c4bh #a #b4 ,shortened ,nicol prism-- a4 ,cemented with ,canada balsam4 #ac #be #b4hc #b b4 ,cemented with copaiba #bd #be #b4hc #b #c4 ,nicol with perpendicular ends-- a4 ,with ,canada balsam4 #bj #ae #c4gc #c b4 ,with cement of index of refraction of #a4ebe4 #bg #ae #c4gc #c #d4 ,foucault's prism4 #h #dj #a4ebh #d #e4 ,hartnack's prism-- a4 ,original form4 #ce #ae4i #c4ea #e a b b4 ,with largest field4 #da4i #ac4i #d4jd #e a a c4 ,with field of #cj4 #cj #ag4d #c4ai #e a c d4 ,with field of #bj4 #bj #bj4c #b4gj #e a d #f4 ,glan's prism4 #g4i #ej4c #j4hca #f ,,ii4 ,,the ,,new ,,polarising ,,prism4 #a4 ,with calc-spar3 largest field4 #dd #ac4b #d4bf #e a a #b4 field of #cj4 #cj #ag4d #c4ai #e a c #c4 field of #bj4 #bj #bj4c #b4gj #e a d #d4 ,with nitrate of soda3 largest field4 #ed #af4g #c4ec #g a a #e4 field of #cj4 #cj #bd #b4be #g a b #f4 field of #bj4 #bj #bg #a4if #g a c ---------------------------------------- -------------------------- ,as an analyzing prism of about #f mm4 clear width1 and #ac4e mm4 long1 the new prism is stated by its inventor to be of the most essential service1 and it would certainly appear that the arrangement is rather better adapted for small prisms than for those of considerable size4 ,any means by which a beam of polarized light of large diameter--say #c to #c inches--could be obtained with all the convenience of a ,nicol would be a real advance1 for spar of sufficient size and purity for such a purpose has become so scarce and therefore so valuable that large prisms are difficult to procure at all4 ,so far as an analyzer is concerned1 the experience of the writer of this notice would lead to the opinion that improvements are to be looked for rather in the way of the discovery of an artificial crystal which absorbs one of the polarized rays than by further modifications depending upon total reflection4 ,the researches of ,dr4 ,herapath on iodosulphate of quinine 7,phil4 ,mag41 ,march1 #aheb1 #afa1 and ,november1 #ahec1 #cdf7 are in this direction2 but crystals of the so-called herapathite require great manipulative skill for their production4 ,if these could be readily obtained of sufficient size1 they would be invaluable as analyzers4 ,this opinion is supported by the existence of an inconvenience which attends every form of analyzing prism4 ,it is frequently1 and especially in projecting apparatus1 required to be placed at the focus of a system of lenses1 so that the rays may cross in the interior of the prism4 ,this is an unfavorable position for a prismatic analyzer1 and in the case of a powerful beam of light1 such as that from the electric arc1 the crossing of the rays within the prism is not unattended with danger to the cementing substance1 and to the surfaces in contact with it4 ,,philip ,r4 ,,sleeman4 99 99 99 99 99 ,,zircon4 ,by ,f4 ,,stolba4 ,finely ground zircon is quickly rendered soluble if fused with a mixture of potassium borofluoride and potassium carbonate4 ,the author takes two parts of the former to three of the latter1 and prepares an intimate1 finely divided mixture1 which is kept ready for use4 ,of this mixture four parts are taken to one of zircon1 thoroughly mixed1 and melted in a platinum crucible at a red heat4 ,the mass fuses readily1 froths at first and gives off bubbles of gas1 and flows then quietly1 forming a very fluid melt4 ,if the zircon is finely ground1 #ae minutes are sufficient for this operation4 ,the loss of weight is #af per cent41 and is not notably increased on prolonged fusion4 ,it corresponds approximately to the weight of the carbonic anhydride present in the potassium carbonate4 ,as pungent vapors are given off during fusion1 the operation should be conducted under a draught hood4 ,the activity of the mixture in attacking zircon appears from the following experiment3 ,two zircon crystals1 each weighing grm41 were introduced into the melted mixture and subjected to prolonged heat4 ,in a short time they decreased perceptibly in size2 each of them broke up into two fragments1 and within an hour they were entirely dissolved4 ,the melted mass is poured upon a dry metal plate1 and when congealed is thrown into water4 ,it is at once intersected with a number of fissures1 which facilitate pulverization4 ,this process is the more necessary as the unbroken mass is very slowly attacked by water even on prolonged boiling4 ,the powder is boiled in a large quantity of water so as to remove everything soluble4 ,there is obtained a faintly alkaline solution and a sediment insoluble in water4 ,from the filtrate alkalies throw down zirconium hydroxide1 free from iron4 ,the portion insoluble in water is readily dissolved in hydrofluoric acid1 and is converted into zircon potassium fluoride4 ,the chief bulk of the zirconium is found in the aqueous solution in the state of double fluorides4 ,the platinum crucible is not in the least attacked during melting4 ,on the contrary1 dirty platinum crucibles may be advantageously cleaned by melting in them a little of the above mentioned mixture4 ,if finely divided zircon is boiled for a long time with caustic lye1 it is perceptibly attacked4 ,it is very probable that in this manner zircon might be entirely dissolved under a pressure of #aj atmospheres4 ,potassium borofluoride may be readily prepared from cryolite4 ,crucibles of nickel seem especially well adapted for the fusion of zircon in caustic alkalies4--,ber4 ,boehm4 ,gesell4 ,wissenschaft2 ,chem4 ,news4 99 99 99 99 99 ,a ,,process ,,for ,,making ,,wrought ,,iron ,,direct ,,from ,,the ,,ore4#a ,footnote #a3 ,a paper read at the ,cincinnati ,meeting of the ,american ,institute of ,mining ,engineers1 by ,willard ,p4 ,ward1 ,a4,m41 ,m4,e41 ,february1 #ahhd4 ,the numerous direct processes which have been patented and brought before the iron masters of the world1 differ materially from that now introduced by ,mr4 ,wilson4 ,after a careful examination of his process1 ,i am convinced that ,mr4 ,wilson has succeeded in producing good blooms from iron ore1 and ,i think that ,i am able to point out theoretically the chief reasons of the success of his method4 ,without going deeply into the history of the metal1 ,i may mention the well known fact that wrought iron was extensively used in almost all quarters of the globe1 before pig or cast iron was ever produced4 ,without entering into the details of the processes by which this wrought iron was made1 it suffices for my present purpose to say that they were crude1 wasteful1 and expensive1 so that they can be employed to-day only in a very few localities favored with good and cheap ore1 fuel1 and labor4 ,the construction of larger furnaces and the employment of higher temperatures led to the production of a highly carbonized1 fusible metal1 without any special design on the part of the manufacturers in producing it4 ,this pig iron1 however1 could be used only for a few purposes for which metallic iron was needed2 but it was produced cheaply and with little loss of metal1 and the attempt to decarbonize this product and bring it into a state in which it could be hammered and welded was soon successfully made4 ,this process of decarbonization1 or some modification of it1 has successfully held the field against all so-called1 direct processes up to the present time4 ,why8 ,because the old fashioned bloomeries and ,catalan forges could produce blooms only at a high cost1 and because the new processes introduced failed to turn out good blooms4 ,those produced were invariably red short1 that is1 they contained unreduced oxide of iron1 which prevented the contact of the metallic particles1 and rendered the welding together of these particles to form a solid bloom impossible4 ,the process of puddling cast iron1 and transforming it by decarbonization into wrought iron1 has1 as everybody knows1 been in successful practical operation for many years1 and the direct process referred to so closely resembles this1 that a short description of the theory of puddling is not out of place here4 ,the material operated on in puddling is iron containing from #b to #d per cent4 of carbon4 ,during the first stage of the process this iron is melted down to a fluid bath in the bottom of a reverberatory furnace4 ,then the oxidation of the carbon contained in the iron commences1 and at the same time a fluid1 basic cinder1 or slag1 is produced1 which covers a portion of the surface of the metal bath1 and prevents too hasty oxidation4 ,this slag results from the union of oxides of iron with the sand adhering to the pigs1 and the silica resulting from the oxidation of the silicon contained in the iron4 ,this cinder now plays a very important part in the process4 ,it takes up the oxides of iron formed by the contact of the oxidizing flame with the exposed portion of the metal bath1 and at the same time the carbon of the iron1 coming in contact with the under surface of the cinder covering1 where it is protected from oxidizing influences1 reduces these oxides from the cinder and restores them to the bath in metallic form4 ,this alternate oxidation of exposed metal1 and its reduction by the carbon of the cast iron1 continues till the carbon is nearly exhausted1 when the iron assumes a pasty condition1 or comes to nature1 as the puddlers call this change4 ,the charge is then worked up into balls1 and removed for treatment in the squeezer1 and then hammered or rolled4 ,in the ,wilson process the conditions which we have noted in the puddling operation are very closely approximated4 ,iron ore reduced to a coarse sand is mixed with the proper proportion of charcoal or coke dust1 and the mixture fed into upright retorts placed in the chimney of the puddling furnace4 ,by exposure for #bd hours to the heat of the waste gases from the furnace1 in the presence of solid carbon1 a considerable portion of the oxygen of the ore is removed1 but little or no metallic iron is formed4 ,the ore is then drawn from the deoxidizer into the rear or second hearth of the puddling furnace1 situated below it1 where it is exposed for #bj minutes to a much higher temperature than that of the deoxidizer4 ,here the presence of the solid carbon1 mixed with the ore1 prevents any oxidizing action1 and the temperature of the mass is raised to a point at which the cinder begins to form4 ,then the charge is carried forward by the workmen to the front hearth1 in which the temperature of a puddling furnace prevails4 ,here the cinder melts1 and at the same time the solid carbon reacts on the oxygen remaining combined with the ore1 and forms metallic iron2 but by this time the molten cinder is present to prevent undue oxidation of the metal formed1 and solid carbon is still present in the mixture to play the same role1 of reducing protoxide of iron from the cinder1 as the carbon of the cast iron does in the ordinary puddling process4 ,i have said that the cast iron used as the material for puddling contains about #c per cent4 of carbon2 but in this process sufficient carbon is added to effect the reduction of the ore to a metallic state1 and leave enough in the mass to play the part of the carbon of the cast iron when the metallic stage has been reached4 ,it would be interesting to compare the ,wilson with the numerous other direct processes to which allusion has already been made1 but there have been so many of them1 and the data concerning them are so incomplete1 that this is impossible4 ,two processes1 however1 the ,blair and the ,siemens1 have attracted sufficient attention1 and are sufficiently modern to deserve notice4 ,in the ,blair process a metallic iron sponge was made from the ore in a closed retort1 this sponge cooled down in receptacles from which the air was excluded1 to the temperature of the atmosphere1 then charged into a puddling furnace and heated for working4 ,in this way 7and the same plan essentially has been followed by other inventors71 the metallic iron1 in the finest possible state of subdivision1 is subjected to the more or less oxidizing influences of the flame1 without liquid slag to save it from oxidation1 and with no carbon present to again reduce the iron oxides from the cinder after it is formed4 ,the loss of metal is consequently very large1 but oxides of iron being left in the metal the blooms are invariably red short4 ,in the ,siemens process pieces of ore of the size of beans or peas1 mixed with lime or other fluxing material1 form the charge1 which is introduced into a rotating furnace2 and when this charge has become heated to a bright-red heat1 small coal of uniform size is added in sufficient quantity to effect the reduction of the ore4 ,the size of the pieces of the material employed prevents the intimate mixture of the particles of iron with the particles of carbon1 and hence we would1 on theoretical grounds1 anticipate just what practice has proved1 viz41 that the reduction is incomplete1 and the resulting metal being charged with oxides is red-short4 ,in practice1 blooms made by this process have been so red-short that they could not be hammered at all4 ,it would be impracticable in this process to employ ore and carbon in as fine particles as ,wilson does1 as a very large portion of the charge would be carried off by the draught1 and a sticking of the material to the sides of the rotating furnace could scarcely be avoided4 ,i do not imagine that a division of the material into anything like the supposed size of molecules is necessary2 we know that the graphitic carbon in the pig-iron employed in puddling is not so finely divided1 but it is much smaller particles than bean or pea size1 and by approximating the size of the graphite particles in pig iron1 ,wilson has succeeded in obtaining good results4 ,if we examine the utilization of the heat developed by the combustion of a given quantity of coal in this process1 and compare it with the result of the combustion of an equivalent amount of fuel in a blast furnace1 we shall soon see the theoretical economy of the process4 ,the coal is burned on the grate of the puddling-furnace1 to carbonic acid1 and the flame is more fully utilized than in an ordinary puddling-furnace1 for besides the ordinary hearth there is the second or rear hearth1 where additional heat is taken up1 and then the products of combustion are further utilized in heating the retorts in which the ore is partly reduced4 ,after this the heat is still further utilized by passing it under the boilers for the generation of steam1 and the heat lost in the gases1 when they finally escape1 is very small4 ,in a blast furnace the carbon is at first burned only to carbonic oxide1 and the products of combustion issue mainly in this form from the top of the furnace4 ,then a portion of the heat resulting from the subsequent burning of these gases is pretty well utilized in making steam to supply the power required about the works1 but the rest of the gas can only be utilized for heating the blast1 and here there is an enormous waste1 the amount of heat returned to the furnace by the heated blast being very small in proportion to the amount generated by the burning of that portion of carbonic oxide expended in heating it1 and the gases escape from both the hot-blast and the boilers at a high temperature4 ,in the direct process under consideration the fuel burned is more completely utilized than in the puddling process1 to which the cast iron from the blast furnace is subjected to convert it into wrought iron4 ,the economy claimed for this process1 over the blast furnace and puddling practice for the production of wrought iron1 is that nearly all the fuel used in the puddling operation is saved1 and that with about the same amount of fuel used in the blast furnace to produce a ton of pig iron1 a ton of wrought iron blooms can be made4 ,i had no opportunity of weighing the charges of ore and coal used1 but ,i saw the process in actual operation at ,rockaway1 ,n4,j4 ,the iron produced was hammered up into good solid blooms1 containing but little cinder4 ,the muck-bar made from the blooms was fibrous in fracture1 and showed every appearance of good iron4 ,i am informed by the manager of the ,sanderson ,brothers' steel works1 at ,syracuse1 ,n4,y41 that they purchased blooms made by the ,wilson process in #ahha-ahhb1 that none of them showed red-shortness1 and that they discontinued their use only on account of the injurious action of the titanium they contained on the melting pots4 ,these blooms were made from magnetic sands from the ,long ,island and ,connecticut coasts4 ,illustration3 ,,new ,,process ,,for ,,making ,,wrought ,,iron ,,from ,,the ,,ore4 ,the drawing given shows the construction of the furnace employed4 ,i quote from the published description3 ,the upper part1 or deoxidizer1 is supported on a strong mantel plate resting on four cast iron columns4 ,the retorts and flues are made entirely of fire-brick1 from special patterns4 ,the outside is protected by a wrought iron jacket made of ,no4 #ad iron4 ,the puddling furnace is of the ordinary construction1 except in the working bottom1 which is made longer to accommodate two charges of ore1 and thus utilize more of the waste heat in reducing the ore to metallic iron4 ,the operation of the furnace is as follows3 ,the pulverized ore is mixed with #bj per cent4 of pulverized charcoal or coke1 and is fed into an elevator which discharges into the hopper on the deoxidizer leading into the retorts marked ,c4 ,these retorts are proportioned so that they will hold ore enough to run the puddling furnace #bd hours1 the time required for perfect deoxidation4 ,after the retorts are filled1 a fire is started in the furnace1 and the products of combustion pass up through the main flue1 or well1 ,b1 where they are deflected by the arch1 and pass out through suitable openings1 as indicated by arrows1 into the down-takes marked ,e1 and out through an annular flue1 where they are passed under a boiler4 ,it will be noticed that the ore is exposed to the waste heat on three sides of the retorts1 and owing to the great surface so exposed1 the ore is very thoroughly deoxidized1 and reduced in the retorts before it is introduced into the puddling furnace for final reduction4 ,the curved cast iron pipes marked ,d are provided with slides1 and are for the purpose of introducing the deoxidized ore into the second bottom of the furnace4 ,as before stated1 the furnace is intended to accommodate two charges of ore1 and as fast as it is balled up and taken out of the working bottom1 the charge remaining in the second bottom is worked up in the place occupied by the first charge1 and a new charge is introduced4 ,as fast as the ore is drawn out from the retorts the elevator supplies a new lot1 so that the retorts are always filled1 thus making the process continuous4 ,the temperature of the charge in the deoxidizer is from #hjj to #a1jjj ,f4--,amer4 ,engineer4 99 99 99 99 99 ,,some ,,remarks ,,on ,,the ,,determination ,,of ,,hardness ,,in ,,waters4 ,by ,,herbert ,,jackson4 ,having had occasion some short time ago to examine a hard water which owed half its hardness to salts of magnesium1 ,i noticed that the soap test1 applied in the usual way1 gave a result which differed very much from that obtained by the quantitative estimation of calcium and magnesium4 ,a perfectly normal lather was obtained when soap had been added in quantities sufficient to neutralize #ad of hardness1 whereas the water contained salts of calcium and magnesium equivalent1 on ,clark's scale1 to a hardness of #bg4 ,although ,i was aware that similar observations had been made before1 ,i thought that it might be useful to determine the conditions under which the soap test could not be depended upon for reliable results4 ,i found with waters containing calcium or magnesium alone that1 whenever salts of either of these metals were in solution in quantities sufficient to give #bc of hardness on ,clark's scale1 no dependence could be placed upon the results given by the soap test4 ,in the case of waters containing salts of both calcium and magnesium1 ,i found that if the salts of the latter metal were in solution in quantities sufficient to give more than #aj of hardness1 no evidence could be obtained of their presence so long as the salts of calcium in the same water exceeded #f2 in such a case a perfect and permanent lather was produced when soap had been added equivalent to #g of hardness4 ,if any water be diluted so as to reduce the proportions of the salts of calcium and magnesium below those stated above1 perfectly reliable results will of course be obtained4 ,instead of dilution ,i found that heating the water to about #gj ,c4 was sufficient to cause a complete reaction between the soap and the salts of calcium and magnesium1 even if these were present in far larger quantities than any given here4 ,the experiments so far had all been made with a solution of ,castile soap of the strength suggested by ,mr4 ,wanklyn in his book on ,water ,analysis4 ,my attention was next directed to the use of any one of the compounds of which such a soap is composed4 ,i commenced with sodium oleate1 and found that by employing this substance in a moderately pure condition1 perfectly reliable results could be obtained in very hard waters without the trouble of either diluting or heating4 ,i was unable to try sodium stearate directly because of the slight solubility of this substance in cold water or dilute alcohol2 but ,i found that a mixture of sodium oleate and stearate behaved in exactly the same manner as the ,castile soap4 ,i am not prepared at present to state the exact reaction which takes place between salts of calcium and magnesium and a compound soap containing sodium oleate and stearate4 ,i publish these results because ,i have not noticed anywhere the fact that some waters show a greater hardness with soap when their temperatures approach the boiling point than they do at the average temperature of the air1 it being1 ,i believe1 the ordinary impression that cold water wastes more soap than hot water before a good and useful lather can be obtained1 whereas with very many waters the case is quite the reverse4 ,neither am ,i aware at present whether it is well known that the use of sodium oleate unmixed with sodium stearate dispenses with the process of dilution even in very hard waters4--,chem4 ,news4 99 99 99 99 99 ,,the ,,density ,,and ,,pressure ,,of ,,detonating ,,gas ,,mixtures4 ,,mm4 ,berthelot and ,vielle have recently been studying the influence of the density of detonating gaseous mixtures upon the pressure developed4 ,the measure of pressure developed by the same gaseous system1 taken under two initial states of different density to which the same quantity of heat is communicated1 is an important matter in thermodynamics4 ,if the pressures vary in the same ratio as the densities1 we may conclude1 independently of all special hypotheses on the laws of gases1 first1 that the specific heat of the system is independent of its density 7that is to say1 of its initial pressure71 and depends only on the absolute temperature1 whatever that may mean2 and secondly1 that the relative variation of the pressure at constant volume1 produced by the introduction of a determinate quantity of heat1 is also independent of the pressure1 and a function only of the temperature4 ,lastly1 the pressure itself will vary proportionally with the absolute temperature1 as defined by the theory of a perfect gas1 and will serve to determine it4 ,,mm4 ,berthelot and ,vielle operated with a bomb1 at first kept at ordinary temperatures in the air1 and afterward heated in an oil bath to #aec deg4 ,cent4 ,they also employed isomeric mixtures of the gases2 methylic ether1 cyanogen1 hydrogen1 acetylene1 and other gases were experimented upon1 and the general conclusions are as follows3 #a4 ,the same quantity of heat being furnished to a gaseous system1 the pressure of the system varies proportionally to the density of the system4 #b4 ,the specific heat of the gas is sensibly independent of the density as well toward very high temperatures as about deg4 ,cent4 ,this is all true for densities near to those that the gas possesses cold under normal pressure1 and which varied in the experiment to double the original value4 #c4 ,the pressure increases with the quantity of heat furnished to the same system4 #d4 ,the apparent specific heat increases parallel with this quantity of heat4 ,these conclusions are independent of all hypotheses on the nature and laws of gases1 and were simply drawn from the experiments in question4 99 99 99 99 99 ,,turkish ,,baths ,,for ,,horses4 ,the ,turkish bath has become an established institution in this country2 men of all classes now use it for sanitary as well as remedial purposes4 ,athletes of various descriptions find it invaluable in training1 and all the distinguished jockeys and light weights keep themselves in condition by its use4 ,it was thought probable that what was good for man might also be good for the horse1 and the fact has been proved4 ,messrs4 ,pickford1 the eminent carriers1 in their hospital for horses at ,finchley1 have had a bath in operation over eleven years1 and find the horses derive great benefit from its use4 ,the bath is put in operation three days a week1 and is administered to over twenty horses in this time4 ,the value of the bath having been thus proved1 it is rather strange that it has not been more generally adopted by the large carrying firms4 ,however1 the ,great ,northern ,railway ,company at their new hospital for horses at ,totteridge1 are erecting a very complete ,turkish bath4 ,it consists of three rooms4 ,first1 a large wash room or grooming room1 from which is entered the first hot room1 or tepidarium1 from #adj to #aej ,fahr42 from this room1 the horse1 after being thoroughly acclimated1 can1 if necessary1 pass to the hottest room1 or calidarium1 from #afj to #agj ,fahr41 and without any turning round can pass on into the grooming and washing room again4 ,this last room is slightly heated from the two other rooms1 and in each are stocks in which the animal can he fastened if required4 ,the heating is done most economically by ,constantine's convoluted stove1 and thorough ventilation is secured from the large volume of hot air constantly supplied1 which passes through the baths1 and as it becomes vitiated is drawn off by specially designed outlets4 ,the wash room is supplied with hot and cold water1 which can1 of course1 be mixed to any required temperature4--,building ,news4 ,illustration ---------------------------------------- --------------- ---------------------------------------- ---- ,,foul ,,air ,,foul ,,air ,,foul ,,air _/ _/ _/ _/ #a,,st ,,hot ,,room _/ _/ _/ _/ _/ _/ ,,curtain ,,washing ,,room #b,,nd ,,hot ,,room ,,fresh _/ ,,air ,,warm ,,foul ,,air ,,foul ,,air ,,air ---------------------------------------- --- ---------------------------------------- --------- ,s ,t ,o ,k ,e ,r ,y ----------------------------------- ------------------------------------- 99 99 99 99 99 ,,miryachit1 ,a ,,newly ,,described ,,disease ,,of ,,the ,,nervous ,,system1 ,,and ,,its ,,analogues4#a ,footnote #a3 ,read before the ,new ,york ,neurological ,society1 ,february #e1 #ahhd4 ,by ,,william ,a4 ,,hammond1 ,m4,d41 ,surgeon-,general1 ,u4,s4 ,army 7,retired ,list72 ,professor of ,diseases of the ,mind and ,nervous ,system in the ,new ,york ,post-,graduate ,medical ,school and ,hospital4 ,in a very interesting account of a journey from the ,pacific ,ocean through ,asia to the ,united ,states1 by ,lieutenant ,b4,h4 ,buckingham and ,ensigns ,george ,c4 ,foulk and ,walter ,mc,lean1#b ,united ,states navy1 ,i find an affection of the nervous system described which1 on account of its remarkable characteristics1 as well as by reason of certain known analogies1 ,i think should be brought to the special notice of the medical profession4 ,i quote from the work referred to1 the following account of this disease4 ,the party is on the ,ussuri ,river not far from its junction with the ,amur in ,eastern ,siberia3 ,while we were walking on the bank here we observed our messmate1 the captain of the general staff 7of the ,russian army71 approach the steward of the boat suddenly1 and1 without any apparent reason or remark1 clap his hands before his face2 instantly the steward clapped his hands in the same manner1 put on an angry look1 and passed on4 ,the incident was somewhat curious1 as it involved a degree of familiarity with the steward hardly to have been expected4 ,after this we observed a number of queer performances of the steward1 and finally comprehended the situation4 ,it seemed that he was afflicted with a peculiar mental or nervous disease1 which forced him to imitate everything suddenly presented to his senses4 ,thus1 when the captain slapped the paddle-box suddenly in the presence of the steward1 the latter instantly gave it a similar thump2 or1 if any noise were made suddenly1 he seemed compelled against his will to imitate it instantly1 and with remarkable accuracy4 ,to annoy him1 some of the passengers imitated pigs grunting1 or called out absurd names2 others clapped their hands and shouted1 jumped1 or threw their hats on the deck suddenly1 and the poor steward1 suddenly startled1 would echo them all precisely1 and sometimes several consecutively4 ,frequently he would expostulate1 begging people not to startle him1 and again would grow furiously angry1 but even in the midst of his passion he would helplessly imitate some ridiculous shout or motion directed at him by his pitiless tormenters4 ,frequently he shut himself up in his pantry1 which was without windows1 and locked the door1 but even there he could be heard answering the grunts1 shouts1 or pounds on the bulkhead outside4 ,he was a man of middle age1 fair physique1 rather intelligent in facial expression1 and without the slightest indication in appearance of his disability4 ,as we descended the bank to go on board the steamer1 some one gave a loud shout and threw his cap on the ground2 looking about for the steward1 for the shout was evidently made for his benefit1 we saw him violently throw his cap1 with a shout1 into a chicken-coop1 into which he was about to put the result of his foraging expedition among the houses of the stanitza4 ,footnote #b3 ,observations upon the ,korean ,coast1 ,japanese-,korean ,ports1 and ,siberia1 made during a journey from the ,asiatic ,station to the ,united ,states1 through ,siberia to ,europe1 ,june #c to ,september #h1 #ahhb4 ,published by the ,united ,states ,navy ,department1 ,washington1 #ahhc1 pp4 #ea4 ,we afterward witnessed an incident which illustrated the extent of his disability4 ,the captain of the steamer1 running up to him1 suddenly clapping his hands at the same time1 accidentally slipped and fell hard on the deck2 without having been touched by the captain1 the steward instantly clapped his bands and shouted1 and then1 in powerless imitation1 he too fell as hard and almost precisely in the same manner and position as the captain4 ,in speaking of the steward's disorder1 the captain of the general staff stated that it was not uncommon in ,siberia2 that he had seen a number of cases of it1 and that it was commonest about ,yakutsk1 where the winter cold is extreme4 ,both sexes were subject to it1 but men much less than women4 ,it was known to ,russians by the name of 'miryachit'4 ,so far as ,i am aware--and ,i have looked carefully through several books of travel in ,siberia--no account of this curious disease has been hitherto published4 ,the description given by the naval officers at once1 however1 brings to mind the remarks made by the late ,dr4 ,george ,m4 ,beard1 before the meeting of the ,american ,neurological ,association in #ahhj1 relative to the ,jumpers or ,jumping ,frenchmen of ,maine and northern ,new ,hampshire4#c ,footnote #c3 ,journal of ,nervous and ,mental ,diseases1 vol4 vii41 #ahhj1 p4 #dhg4 ,in ,june1 #ahhj1 ,dr4 ,beard visited ,moosehead ,lake1 found the ,jumpers1 and experimented with them4 ,he ascertained that whatever order was given them was at once obeyed4 ,thus1 one of the jumpers who was sitting in a chair with a knife in his hand was told to throw it1 and he threw it quickly1 so that it stuck in a beam opposite2 at the same time he repeated the order to throw it with a cry of alarm not unlike that of hysteria or epilepsy4 ,he also threw away his pipe1 which he was filling with tobacco1 when he was slapped upon the shoulder4 ,two jumpers standing near each other were told to strike1 and they struck each other very forcibly4 ,one jumper1 when standing by a window1 was suddenly commanded by a person on the other side of the window to jump1 and he jumped up half a foot from the floor1 repeating the order4 ,when the commands are uttered in a quick1 loud voice1 the jumper repeats the order4 ,when told to strike he strikes1 when told to throw he throws whatever he may happen to have in his hand4 ,dr4 ,beard tried this power of repetition with the first part of the first line of ,virgil's neid and the first part of the first line of ,homer's ,iliad1 and out-of-the-way words of the ,english language with which the jumper could not be familiar1 and he repeated or echoed the sound of the word as it came to him in a quick1 sharp voice1 at the same time he jumped1 or struck1 or threw1 or raised his shoulders1 or made some other violent muscular motion4 ,they could not help repeating the word or sound that came from the person that ordered them1 any more than they could help striking1 dropping1 throwing1 jumping1 or starting2 all of these phenomena were indeed but parts of the general condition known as jumping4 ,it was not necessary that the sound should come from a human being2 any sudden or unexpected noise1 as the explosion of a gun or pistol1 the falling of a window1 or the slamming of a door--provided it was unexpected and loud enough--would cause these jumpers to exhibit some one or all of these phenomena4 ,one of these jumpers came very near cutting his throat1 while shaving1 on hearing a door slam4 ,they had been known to strike their fists against a red-hot stove1 to jump into the fire and into water4 ,they could not help striking their best friend if near them when ordered4 ,the noise of a steam whistle was especially obnoxious to them4 ,one of these jumpers1 when taking some bromide of sodium in a tumbler1 was told to throw it1 and he dashed the tumbler upon the floor4 ,it was dangerous to startle them in any way when they had an ax or an knife in their hands4 ,all of the jumpers agreed that it tired them to be jumped1 and they dreaded it1 but they were constantly annoyed by their companions4 ,from this description it will at once1 ,i think1 be perceived that there are striking analogies between miryachit and this disorder of the ,jumping ,frenchmen of ,maine4 ,indeed1 it appears to me that1 if the two affections were carefully studied1 it would be found that they were identical1 or that1 at any rate1 the phenomena of the one could readily be developed into those of the others4 ,it is not stated that the subjects of miryachit do what they are told to do4 ,they require an example to reach their brains through the sense of sight or that of hearing1 whereas the ,jumpers do not apparently perform an act which is executed before them1 but they require a command4 ,it seems1 however1 that a ,jumper starts whenever any sudden noise reaches his ears4 ,in both classes of cases a suggestion of some kind is required1 and then the act takes place independently of the will4 ,there is another analogous condition known by the ,germans as ,schlaftrunkenheit1 and to ,english and ,american neurologists as somnolentia1 or sleep-drunkenness4 ,in this state an individual1 on being suddenly awakened1 commits some incongruous act of violence1 ofttimes a murder4 ,sometimes this appears to be excited by a dream1 but in others no such cause could be discovered4 ,thus1 a sentry fell asleep during his watch1 and1 being suddenly aroused by the officer in command1 attacked the latter with his sword1 and would have killed him but for the interposition of the bystanders4 ,the result of the medical examination was that the act was involuntary1 being the result of a violent confusion of mind consequent upon the sudden awaking from a profound sleep4 ,other cases are cited by ,wharton and ,stille in their work on medical jurisprudence1 by ,hoffbauer1 and by myself in ,sleep and its ,derangements4 ,the following cases among others have occurred in my own experience3 ,a gentleman was roused one night by his wife1 who heard the street-door bell ring4 ,he got up1 and1 without paying attention to what she said1 dragged the sheets off of the bed1 tore them hurriedly into strips1 and proceeded to tie the pieces together4 ,she finally succeeded in bringing him to himself1 when he said he had thought the house was on fire1 and he was providing means for their escape4 ,he did not recollect having had any dream of the kind1 but was under the impression that the idea had occurred to him at the instant of his awaking4 ,another was suddenly aroused from a sound sleep by the slamming of a window-shutter by the wind4 ,he sprang instantly from his bed1 and1 seizing a chair that was near1 hurled it with all his strength against the window4 ,the noise of the breaking of glass fully awakened him4 ,he explained that he imagined some one was trying to get into the room and had let his pistol fall on the floor1 thereby producing the noise which had startled him4 ,in another case a man dreamed that he heard a voice telling him to jump out of the window4 ,he at once arose1 threw open the sash1 and jumped to the ground below1 fortunately only a distance of about ten feet1 so that he was not injured beyond receiving a violent shock4 ,such a case as this appears to me to be very similar to those described by ,dr4 ,beard in all its essential aspects4 ,a few years ago ,i had a gentleman under my charge who would attempt to execute any order given him while he was asleep by a person whispering into his ear4 ,thus1 if told in this way to shout1 he shouted as loud as he could2 if ordered to get up1 he at once jumped from the bed2 if directed to repeat certain words1 he said them1 and so on4 ,i am not able to give any certain explanation of the phenomena of miryachit or of the ,jumpers1 or of certain of those cases of sleep-drunkenness which seem to be of like character4 ,but they all appear to be due to the fact a motor impulse is excited by perceptions without the necessary concurrence of the volition of the individual to cause the discharge4 ,they are1 therefore1 analogous to reflex actions1 and especially to certain epileptic paroxysms due to reflex irritations4 ,it would seem as though the nerve cells were very much in the condition of a package of dynamite or nitro glycerin1 in which a very slight impression is sufficient to effect a discharge of nerve force4 ,they differ1 however1 from the epileptic paroxysm in the fact that the discharge is consonant with the perception--which is in these cases an irritation--and is hence an apparently logical act1 whereas in epilepsy the discharge is more violent1 is illogical1 and does not cease with the cessation of the irritation4 ,certainly the whole subject is of sufficient importance to demand the careful study of competent observers4 99 99 99 99 99 ,,the ,,gum ,,disease ,,in ,,trees4#a ,footnote #a3 ,communicated to the ,medical ,times by ,sir ,james ,paget4 ,an essay by ,dr4 ,beijerinck1 on the contagion of the gum disease in plants1 lately published by the ,royal ,academy of ,sciences at ,amsterdam1 contains some useful facts4 ,the gum disease 7gummosis1 gum-flux7 is only too well known to all who grow peaches1 apricots1 plums1 cherries1 or other stone fruits4 ,a similar disease produces gum arabic1 gum tragacanth1 and probably many resins and gum resins4 ,it shows itself openly in the exudation of thick and sticky or hard and dry lumps of gum1 which cling on branches of any of these trees where they have been cracked or wounded through the bark4 ,dr4 ,beijerinck was induced to make experimental inoculations of the gum disease by suspicions that1 like some others observed in plants1 it was due to bacteria4 ,he ascertained that it is in a high degree contagious1 and can easily be produced by inserting the gum under the edge of a wound through the bark of any of the trees above named4 ,the observation that heated or long boiled pieces of gum lose their contagious property made it most probable that a living organism was concerned in the contagions2 and he then found that only those pieces of the gum conveyed contagion in which1 whether with or without bacteria1 there were spores of a relatively highly organized fungus1 belonging to the class of ,ascomycetes2 and that these spores1 inserted by themselves under the bark1 produced the same pathological changes as did the pieces of gum4 ,the fungus thus detected1 was examined by ,professor ,oudemans1 who ascertained it to be a new species of ,coryneum1 and has named it ,coryneum ,beijerincki4 ,the inoculation experiments are best made by means of incisions through the bark of young branches of healthy peach trees or cherry trees1 and by slightly raising the cut edge of the bark and putting under it little bits of gum from a diseased tree of the same kind4 ,in nearly every instance these wounds become the seats of acute gum disease1 while similar wounds in the same or other branches of the same tree1 into which no gum is inserted1 remain healthy1 unless1 by chance1 gum be washed into them during rain4 ,the inoculation fails only when the inserted pieces of gum contain no ,coryneum4 ,by similar inoculations similar diseases can be produced in plum1 almond1 and apricot trees1 and with the gum of any one of these trees any other can be infected2 but of many other substances which ,beijerinck tried1 not one produced any similar disease4 ,the inoculation with the gum is commonly followed by the death of more or less of the adjacent structures2 first of the bark1 then of the wood4 ,small branches or leaf stalks thus infected in winter1 or in many places at the same time1 may be completely killed2 but1 in the more instructive experiments the first symptom of the gum disease is the appearance of a beautiful red color around the wound4 ,it comes out in spots like those which often appear spontaneously on the green young branches of peach trees that have the gum disease2 and in these spots it is usual to find ,coryneum stromata or mycelium filaments4 ,the color is due to the formation of a red pigment in one or more of the layers of the cells of the bark4 ,but in its further progress the disease extends beyond the parts at which the ,coryneum or any structures derived from it can be found2 and this extension1 ,beijerinck believes1 is due to the production of a fluid of the nature of a ferment1 produced by the ,coryneum1 and penetrating the adjacent structures4 ,this1 acting on the cell walls1 the starch granules1 and other constituents of the cells1 transforms them into gum1 and even changes into gum the ,coryneum itself1 reminding the observer of the self-digestion of a stomach4 ,in the cells of the cambium1 the same fluid penetrating unites with the protoplasm1 and so alters it that the cells produced from it form1 not good normal wood1 but a morbid parenchymatous structure4 ,the cells of this parenchyma1 well known among the features of gum disease1 are cubical or polyhedral1 thin walled1 and rich in protoplasm4 ,this1 in its turn1 is transformed into gum1 such as fills the gum channels and other cavities found in wood1 and sometimes regarded as gum glands4 ,and from this also the new ferment fluid constantly produced1 and tracking along the tissues of the branches1 conveys the ,coryneum infection beyond the places in which its mycelium can be found4 99 99 99 99 99 ,,drinkstone ,,park4 ,drinkstone has long been distinguished on account of the successful cultivation of remarkable plants4 ,it lies some eight miles southeast from ,bury ,st4 ,edmund's1 and is the seat of ,t4,h4 ,powell1 ,esq4 ,the mansion or hall is a large old-fashioned edifice1 a large portion of its south front being covered by a magnificent specimen of the ,magnolia grandiflora1 not less than #dj feet in height1 while other portions of its walls are covered with the finest varieties of climbing roses and other suitable plants4 ,the surrounding country1 although somewhat flat1 is well wooded1 and the soil is a rich loam upon a substratum of gravel1 and is consequently admirably suited to the development of the finer kinds of coniferous and other ornamental trees and shrubs1 so that the park and grounds contain a fine and well selected assortment of such plants4 ,illustration3 ,,the ,,snowflake1 ,,leucojum ,,vernum1 ,,at ,,drinkstone ,,park4 ,coniferous trees are sometimes considered as out of place in park scenery2 this1 however1 does not hold good at ,drinkstone1 where ,mr4 ,powell has been displayed excellent taste in the way of improving the landscape and creating a really charming effect by so skillfully blending the dressed grounds with the rich greensward of the park that it is not easy to tell where the one terminates or the other commences4 ,the park1 which covers some #bjj acres1 including a fine lake over eight acres in extent1 contains also various large groups or clumps of such species as the ,sequoia gigantea1 ,taxodium sempervirens1 ,cedres deodora1 ,picea douglasii1 ,pinsapo1 etc41 interspersed with groups of ornamental deciduous trees1 producing a warm and very pleasing effect at all seasons of the year4 ,among species which are conspicuous in the grounds are fine1 well-grown examples of ,araucaria imbricata1 some #cj feet high2 ,cedrus deodara1 #fj feet in height2 ,abies pinsapo1 #dj feet2 and fine specimens of ,abies grandis1 ,a4 nobilis1 and ,a4 nordmanniana1 etc41 together with ,abies albertiana or mertensiana1 a fine1 free-growing species2 also ,libocedrus gigantea1 ,thuiopsis borealis1 ,thuia lobbii1 ,juniperus recurva1 ,taxas adpressa1 fine plants2 with fine golden yews and equally fine examples of the various kinds of variegated hollies1 etc4 ,illustration3 ,,odontoglossum ,,rossi ,,major ,,var4 ,,rubescens1 ,,at ,,drinkstone ,,park4 ,particular attention is here paid to early spring flowers4 ,drinkstone is also celebrated as a fruit growing establishment1 more particularly as regards the grape vine2 the weight and quality of the crops of grapes which are annually produced here are very remarkable4--,the ,gardeners' ,chronicle4 99 99 99 99 99 ,,on ,,the ,,changes ,,which ,,take ,,place ,,in ,,the ,,conversion ,,of ,,hay ,,into ,,ensilage4 ,by ,,fredk4 ,,jas4 ,,lloyd1 ,f4,c4,s41 ,lecturer on ,agriculture1 ,king's ,college4 ,the recently published number of the ,royal ,agricultural ,society's ,journal contains some information upon the subject of silage which appears to me of considerable interest to those chemists who are at present investigating the changes which take place in the conversion of grass into silage4 ,the data#a are1 so far as ,i know1 unique1 and though the analytical work is not my own1 yet it is that of an agricultural chemist1 ,mr4 ,a4 ,smetham1 of ,liverpool1 whose work ,i know from personal experience to be thoroughly careful and reliable4 ,i have therefore no hesitation in basing my remarks upon it4 ,footnote #a3 ,royal ,agricultural ,society's ,journal1 vol4 xx41 part i41 pp4 #age and #chj4 ,we have here for the first time an accurate account of the quantity of grass put into a silo1 of the quantity of silage taken out1 and of the exact composition both of the grass and resulting silage4 ,i desire merely to place myself in the position of1 so to speak1 a chemical accountant4 ,the ensilage has been analyzed at three depths1 or rather in three layers1 the first being #a foot1 the second #a ft4 to #a ft4 #f in41 and the third #a ft4 #f in4 to #b ft4 from the bottom of the silo4 ,by doubling the figures of the bottom layer analysis1 adding these to the second and third layer analysis1 and dividing by #d1 we obtain a fair representation of the average composition of the silage taken throughout the silo1 for by so doing we obtain the average of the analyses of each #f-;inch layer of silage4 ,the results of the analyses are as follows1 calculated on the dry matter4 ,the moisture was practically the same1 being #gj4dh per cent1 in the grass and #gb4ig in the silage4 ,composition of ,grass and ,silage 7dried at #ajj;,c474 ,grass4 ,ensilage4 ,fat 7ether extract7 #b4hj #e4ch ,soluble albuminous compounds #c4jf #e4ih ,insoluble albuminous compounds #f4id #c4gg ,mucilage1 sugar1 and extractives1 etc4 #aa4fe #d4ih ,digestible fiber #cf4bd #cc4cg ,indigestible woody fiber #cb4cc #ca4gi ------- ------- #ic4jb #he4bg ,soluble mineral matters #e4bd #ab4fb ,insoluble mineral matters #a4gd #b4aa ------- ------- #ajj4jj #ajj4jj ,the striking difference in the mineral matter of the grass and silage ,i will merely draw attention to2 it is not due to the salt added to the silage4 ,i may say1 however1 that other analysts and ,i myself have found similar striking differences4 ,for instance1 ,prof4 ,kinch#b found in grass #h4ej per cent4 mineral matter1 in silage #aj4aj per cent41 which1 as be points out1 is equivalent1 to a loss of about #ah per cent4 of combustible constituents--a loss which we have no proof of having taken place4 ,in ,mr4 ,smetham's sample the loss would have to be #ej per cent41 which did not occur1 and in fact is not possible4 ,what is the explanation8 ,footnote #b3 ,journ4 ,chem4 ,society1 ,march1 #ahhd1 p4 #abd4 ,i am1 however1 considering now the organic constituents4 ,calculating the percentages of these in the grass and silage1 we obtain the following figures3 ,percentage ,composition of ,organic ,compounds4 ,grass4 ,ensilage4 ,fat 7ether extract7 #c4ja #f4ca ,soluble albuminous compounds #h4bi #g4ja #aj4ge #aa4dc ,insoluble #g4df #d4db ,mucilage1 sugar1 and extractives #ab4eb #e4hd ,digestible fiber #ch4if #ci4ad ,indigestible woody fiber #cd4gf #cg4bh ------- ------- #ajj4jj #ajj4jj ,the difference in the total nitrogen in the grass and silage is equal to #j4fh per cent4 of albuminoids4 ,practically it is a matter of impossibility that the nitrogen could have increased in the silo1 and it will be a very safe premise upon which to base any further calculations that the total amount of nitrogen in the silage was identical with that in the grass4 ,there may have been a loss1 but that is not yet proved4 ,arguing then upon the first hypothesis1 it is evident that #ajj parts of the organic matters of silage represent more than #ajj parts of the organic matter of grass1 and by the equation we obtain #aj4ge3aa4dc 33 #ajj3ajf approximately4 ,if now we calculate the composition of #ajf parts organic matter of grass1 it will represent exactly the organic matter which has gone to form #ajj parts of that present in silage4 ,the following table gives these results1 and also the loss or gain in the various constitutents arising from the conversion into silage3 ,organic ,matter4 ,in #ajf pts4 ,in #ajj pts4 ,loss or ,grass4 ,silage4 ,gain4 ,fat 7ether extract7 #c4ai #f4ca #c4ab ,soluble albuminous compounds #c4di #g4ja #c4eb ,insoluble #g4ia #d4db -#c4di ,mucilage #ac4bg #e4hd -#g4dc ,digestible ,fiber #da4cj #ci4ad -#b4af ,indigestible woody fiber #cf4hd #cg4bh #j4dd ------- ------- #ajf4jj #ajj4jj ,these calculations show1 provided my reasoning be correct1 that the chief changes which take place are in the albuminous compounds1 which has already been pointed out by ,professors ,voelcker1 ,kinch1 and others2 and in the starch1 gum1 mucilage1 sugar1 and those numerous bodies termed extractives1 which was to be expected4 ,but they show most conclusively that the decrease in the amount of indigestible fiber and increase in digestible so much spoken of is1 so far as our present very imperfect methods of analyzing these compounds permit us to judge1 a myth2 and ,i have not yet found any sufficient evidence to support this statement4 ,a loss1 then1 of #f parts of organic matter out of every #ajf parts put into the silo has in this instance taken place1 due chiefly to the decomposition of starch1 sugar1 and mucilage1 etc4 ,and as the grass contained #gj parts of water when put into the silo1 the total loss would only be #a4g per cent4 of the total weight4 ,this theoretical deduction was found by practical experience correct1 for ,mr4 ,smith1 agent to ,lord ,egerton1 upon whose estate this silage was made1 in his report to ,mr4 ,jenkins says the actual weight out of the silo corresponds exactly with the weight we put into the same4 ,in my judgment these figures are of interest to the agricultural chemist for many reasons4 ,first1 they will clear the ground for future workers and eliminate from their researches what would have greatly complicated them--changes in the cellulose bodies4 ,secondly1 they are of interest because our present methods of distinguishing between and estimating digestible and indigestible fiber is most rough1 and probably inaccurate1 and may not in the least represent the power of an animal--say a cow--to digest these various substances2 and most of us know that when a new method of analysis becomes a necessity1 a new method is generally discovered4 ,lastly1 they are of interest to the agriculturist1 for they point out1 ,i believe for the first time1 the exact amount of loss which grass--or at least one sample--has undergone in conversion into silage1 and also that much of the nitrogenous matter is changed1 and so far as we know at present1 lost its nutritive value4 ,this1 however1 is only comparing silage with grass4 ,what is wanted is to compare silage with hay--both made out of the same grass4 ,then1 and then only1 will it be possible to sum up the relative advantages or disadvantages of the two methods of preserving grass as food for cattle4--,chem4 ,news4 99 99 99 99 99 ,,the ,,illuminating ,,power ,,of ,,ethylene4 ,dr4 ,percy ,frankland has obtained results which may be thus briefly summarized3 7#a47 ,that pure ethylene1 when burnt at the rate of #e cubic feet per hour from a ,referee's ,argand burner1 emits a light of #fh4e standard candles4 7#b47 ,that the illuminating power of equal volumes of mixtures of ethylene with either hydrogen carbonic oxide or marsh-gas is less than that of pure ethylene4 7#c47 ,that when the proportion of ethylene in such mixtures is above #fc per cent4 the illuminating power of the mixture is but slightly affected by the nature of the diluent4 ,when1 on the other hand1 the proportion of ethylene in such mixtures is low1 the illuminating power of the mixture is considerably the highest when marsh-gas is the diluent1 and the lowest when the ethylene is mixed with carbonic oxide4 7#d47 ,that if #e cubic feet of ethylene be uniformly consumed irrespectively of the composition of the mixture1 the calculated illuminating power is in every case equal to or actually greater than that of pure ethylene until a certain degree of dilution is attained4 ,this intrinsic luminosity of ethylene remains almost constant when the latter is diluted with carbonic oxide1 until the ethylene forms only #dj per cent4 of the mixture1 after which it rapidly diminishes to zero when the ethylene forms only #bj per cent4 of the mixture4 ,when the ethylene is diluted with hydrogen1 its intrinsic luminosity rises to #ha candles when the ethylene constitutes #cj per cent4 of the mixture1 after which it rapidly falls to zero when the ethylene amounts to only #aj per cent4 ,in the case of mixtures of ethylene and marsh-gas1 the intrinsic luminosity of the former is augmented with increasing rapidity as the proportion of marsh gas rises1 the intrinsic luminosity of ethylene1 in a mixture containing #aj per cent4 of the latter1 being between #agj and #ahj candles4 99 99 99 99 99 ,,diffraction ,,phenomena ,,during ,,total ,,solar ,,eclipses4#a ,footnote #a3 ,a paper read before the ,american ,astronomical ,society1 ,may #e1 #ahhd4 ,by ,g4,d4 ,hiscox4 ,the reality of the sun's corona having been cast in doubt by a leading observer of the last total eclipse1 who1 from the erratic display observed in the spectroscope1 has declared it a subjective phenomenon of diffraction1 has led me to an examination and inquiry as to the bearing of an obscurely considered and heretofore only casually observed phenomenon seen to take place during total solar eclipses4 ,this phenomenon1 it seems to me1 ought to account for1 and will possibly satisfy1 the spectroscopic conditions observed just before1 during1 and after totality2 which has probably led to the epithet used by some leading observers--the fickle corona4 ,the peculiar phenomenon observed in the spectroscope1 the flickering bands or lines of the solar spectrum flashing upon and across the coronal spectrum1 has caused no little speculation among observers4 ,the diffraction or interference bands projected by the passage of a strong beam of light by a solid body1 as discovered long since by ,grimaldi1 and investigated later by ,newton1 ,fresnel1 and ,fraunhofer1 are explained and illustrated in our text books2 but the grand display of this phenomenon in a total solar eclipse1 where the sun is the source of light and the moon the intercepting body1 has as yet received but little attention from observers1 and is not mentioned to my knowledge in our text books4 ,in the instructions issued from the ,united ,states ,naval ,observatory and the ,signal ,office at ,washington for the observation of the eclipse of ,july #bi1 #ahgh1 attention was casually directed to this phenomenon1 and a few of the observers at ,pike's ,peak1 ,central ,city1 ,denver1 and other places have given lucid and interesting descriptions of the flight of the diffraction bands as seen coursing over the face of the earth at the speed of the moon's shadow1 at the apparent enormous velocity of thirty-three miles per minute1 or fifty times the speed of a fast railway train4 ,from a known optical illusion derived from interference or fits of perception1 as illustrated in quick moving shadows1 this great speed was not realized to the eye1 as the observed motion of these shadows was apparently far less rapid than their reality4 ,the ultra or diffraction bands outside of the shadow were distinctly seen and described by ,mr4 ,j4,e4 ,keeler at ,central ,city1 both before and after totality4 ,he estimates the shadow bands at #h inches wide and #d feet apart4 ,professor ,e4,s4 ,holden1 also at ,central ,city1 estimated the dark bands as about #c feet apart1 and variable4 ,from estimates which he obtained from other observers of his party1 the distances between the bands varied from #f to l feet1 but so quickly did they pass that they baffled all attempts to count even the number that passed in one second4 ,he observed the time of continuance of their passage from west to east as forty-eight seconds1 which indicates a width of #cc miles of diffraction bands stretching outward from the edge of the shadow to the number of many thousands4 ,mr4 ,g4,w4 ,hill1 at ,denver1 a little to the north of the central track of the shadow1 observed the infra or bands within the shadow1 alluding to the fact that they must be moving at the same rate as the shadow1 although their apparent motion was much slower1 or like the shadows of flying clouds4 ,he attributes the discrepancy to optical illusion4 ,at ,virginia ,city the colors of the ultra bands were observed1 and estimated at five seconds' duration from the edge of the shadow1 which is equal to about #d miles in width4 ,these are known to be the strongest color bands in the diffraction spectrum1 which accounts for their being generally observed4 ,mr4 ,w4,h4 ,bush1 observing at ,central ,city1 in a communication to ,prof4 ,holden alludes to the brilliancy of the colors of these bands as seen through small clouds floating near the sun's place during totality1 and of the rapid change of their rainbow colors as observed dashing across the clouds with the rapidity of thought4 ,all of these bands1 both ultra and infra1 as seen in optical experiments1 are colored in reverse order1 being from violet to red for each band outward and inward from the edge of the shadow4 ,it is very probable that the velocity of the passage of all the bands during a total eclipse very much modifies the distinctness of the colors or possibly obliterates them by optically blending so as to produce the dull white and black bands which occupied so large a portion of this grand panorama4 ,the phenomenon of these faint colored bands1 with the observed light and dark shadows1 may be attributed to one or all of the following causes3 #a4 ,a change in the direction of a small portion of the sun's light passing by the solid body of the moon1 it being deflected outward by repulsion or reflection from its surface1 and other portions being deflected inward after passing the body by mutual repulsion of its own elements toward a light vacuum or space devoid of the element of vibration4 #b4 ,the colored spectral bands being the direct result of the property of interference1 or the want of correspondence of the wave lengths due to divergence2 the same phenomenon being also observed in convergent light4 ,this is practically illustrated in the hazy definition of the reduced aperture of telescopes1 and its peculiarities shown in the spectral rings within and beyond the focus4 #c4 ,chromatic dispersion by our atmosphere1 together with selective absorption1 also by our atmosphere and its vapors1 have been suggested as causes in this curious and complicated phenomena4 ,in none of the reports descriptive of the phenomena of polarization of the corona is there the slightest allusion to the influence that the diffraction bands may possibly have in modifying or producing the various conditions of polarization observed2 although these observations have been made and commented upon during the past twenty-five years4 ,investigations now in progress of the modifying relation of the phenomenon of diffraction in its effect upon not only the physical aspect of the corona1 but also in some strange spectroscopic anomalies that have been observed near the sun at other times than during a total solar eclipse1 will1 it is hoped1 result in a fuller interpretation of the physical nature of one of the grandest elements of creation--light2 let there be more of it4 99 99 99 99 99 ,a ,,catalogue containing brief notices of many important scientific papers heretofore published in the ,,supplement1 may be had gratis at this office4 99 99 99 99 99 ,the ,scientific ,american ,supplement4 ,,published ,,weekly4 ,terms of ,subscription1 #e a ,year4 ,sent by mail1 postage prepaid1 to subscribers in any part of the ,united ,states or ,canada4 ,six dollars a year1 sent1 prepaid1 to any foreign country4 ,all the back numbers of ,,the 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