,,lightning ,,rod ,,conference4 ,,report ,,of ,,the ,,delegates ,,from ,,the ,,following ,,societies1 ,,viz43 ,,meteorological ,,society4 ,c4 ,,brooke1 ,f4,r4,s41 ,past ,president ,,the ,,late4 ,e4 ,e4 ,,dymond1 ,f4,m4,s41 ,vice-,president4 ,g4 ,j4 ,,symons1 ,f4,r4,s41 ,president4 ,,royal ,,institute ,,of ,,british ,,architects4 ,,prof4 ,,lewis1 ,f4,s4,a41 ,vice-,president4 ,j4 ,,whichcord1 ,f4,s4,a41 ,past ,president4 ,,society ,,of ,,telegraph ,,engineers ,,and ,,of ,,electricians4 ,,latimer ,,clark1 ,m4 ,,inst4 ,c4,e41 ,past ,president4 ,w4 ,h4 ,,preece1 ,f4,r4,s41 ,m4 ,,inst4 ,c4,e41 ,past ,president4 ,,physical ,,society4 ,,prof4 ,w4 ,g4 ,,adams1 ,f4,r4,s41 ,past ,president4 ,,prof4 ,g4 ,,carey ,,foster1 ,f4,r4,s41 ,past ,president4 ,,co-,,opted ,,members4 ,,prof4 ,w4 ,e4 ,,ayrton1 ,f4,r4,s4 ,,prof4 ,d4 ,e4 ,,hughes1 ,f4,r4,s4 ,with a ,code of ,rules for the ,erection of ,lightning ,conductors2 and various ,appendices4 ,,edited ,,by ,,the ,,secretary1 ,g4 ,j4 ,,symons1 ,f4,r4,s4 ,,london3 ,e4 ,f4 ,n4 ,,spon1 #af1 ,,charing ,,cross4 ,,new ,,york3 #ddf1 ,,broome ,,street4 #ahhb4 ,,kenny ,,co41 ,,printers1 #be1 ,,camden ,,road1 ,n4,w4 ---------------------------------------- -------------------------------- ,,contents4 ,,page ,,preface v ,,report #a ,section #a4--,the purpose which a lightning conductor is intended to serve #a ,section #b4--;,a statement of those features in the ,construction and ,erection of ,lightning ,conductors1 respecting which there has been1 or is1 a difference of opinion1 and the final decision of the ,conference thereupon #c ,points #c ,material for ,conductor #e ,size of ,rod #f ,shape of ,rod 7,rod1 ,tube1 ,tape1 ,rope1 ,plait7 #g ,joints #aj ,protection of ,rod #aj ,painting #aa ,attachment to ,buildings #aa ,earth ,plates #aa ,space ,protected #ab ,height of ,upper ,terminal #ad ,testing ,conductors #ad ,internal ,masses of ,metal #ae ,external ,masses of ,metal #af ,section #c4--;,code of ,rules for the ,erection of ,lightning ,conductors #af ,,appendices-- ,a4--,circular and ,questions issued to ,manufacturers1 and their ,replies 7#a7 ,b4--,analysis of1 and remarks upon1 the views of the ,manufacturers 7#ag7 ,c4--,reply from ,manufacturers received after the completion of ,appendix ,b4 7#bc7 ,d4--,report of the ,representatives of the ,royal ,institute of ,british ,architects 7#bg7 ,e4--,particulars of ,accidents by ,lightning1 collected #aheg-ei1 by ,mr4 ,symons1 and ,report upon the same 7#dc7 ,f4--,abstracts of ,printed ,documents 7#ea7 ,g4--,catalogue of ,works upon ,lightning ,conductors 7#adc7 ,h4--,application to1 and ,replies from1 the ,local ,hon4 ,secretaries of the ,society of ,telegraph ,engineers and other distinguished ,foreign ,authorities 7#age7 ,i4--,general ,correspondence 7#ahc7 ,j4--,data respecting the ,sectional ,area of ,metal requisite for ,lightning ,conductors 7#bbc7 ,k4--,notes respecting ,lightning ,conductors1 collected in ,paris in ,may1 #ahha1 by ,messrs4 ,preece and ,symons 7#bbe7 ,l4--,on the ,lightning ,conductors at the ,paris ,international ,electrical ,exhibition1 by ,messrs4 ,dymond and ,symons 7#bbi7 ,m4--,miscellaneous 7#bcc7 ,index to ,appendices 7#bde7 ,,illustrations4 ,,page ,sketch illustrative of terms employed face x ,sketch illustrative of area of protection #ac ,plans and ,elevation of ,nottingham ,castle 7#be7 7#bf7 ,tower of ,church of ,week ,st4 ,mary1 ,cornwall 7#cb7 ,plan and ,elevation of ,twyford ,moors1 ,winchester 7#cd7 ,plan and ,elevation of ,st4 ,james' ,church1 ,west-,end1 ,hants4 7#ce7 ,plan and ,elevation of houses at ,lewisham1 ,wandsworth1 and ,forest 7#ch7 ,hill ,view of ,tower of ,holborn ,union ,infirmary1 ,holloway 7#dj7 ,plan and ,elevation of ,laundry at ,gravesend 7#da7 ,regnier's ,system of ,lightning ,conductors 7#ed7 ,joints and ,earth ,terminals recommended in ,france in #ahjg 7#ee7 ,powder ,magazine1 with oblique as well as vertical rods 7#eg7 ,mode of attaching ,conductor to ,upper ,terminal 7#ei7 ,view and ,plan of ,bruntcliffe ,gunpowder ,store 7#ge7 ,view of ,board ,house1 at ,purfleet 7#gh7 ,view and ,plan of ,heckingham ,poorhouse 7#hg7 7#hh7 ,diagrams illustrative of space protected 7#ace7 7#acf7 ,plan and ,elevation of ,church of ,ste4 ,croix1 at ,ixelles 7#ada7 ,sketch of arrangements for ,public ,buildings in ,denmark 7#agg7 ,plan and ,elevations of ,systems for ,powder ,magazines in ,denmark 7#agh7 ,attachment and ,earth ,terminal used in ,italy 7#ahj7 ,sections of ,rods used by the ,trinity ,board 7#ahc7 ,eddystone and ,spurn ,point ,lighthouses 7#ahd7 ,south ,foreland ,high ,light 7#ahe7 ,eddystone ,lighthouse 7#aia7 ,plan and ,elevation of house at ,trolley ,bottom1 ,st4 ,albans 7#aig7 ,plan and ,elevation of washhouse of ,middlesboro' ,fever ,hospital 7#bjc7 ,plan and ,elevation of ,indian ,pagoda 7#bjg7 ,plan and ,elevation of ,upwood ,gorse1 ,caterham 7#baa7 ,sections of ,rod at ,upwood ,gorse1 ,caterham 7#bad7 7#bae7 ,sections of ,munson's ,rods 7#baf7 ,view and ,section of ,cutting's ,conductor ,coupling 7#bag7 ,plan and ,elevation of ,christ ,church1 ,carmarthen 7#bah7 ,plan and ,view of house1 and of ,bootham ,bar1 ,york 7#bbj7 7#bba7 ,,preface4 ,although ,france and other nations have taken active steps to give official sanction to the best known means of protection from the ill effects of atmospheric electricity1 nothing in this way has ever been done in ,england for the public generally4 ,the enquiries by householders and public bodies for advice and instruction were so numerous1 the absence of authorized or well-matured directions was so marked1 the practice in vogue so varied and anomalous1 that it occurred to the ,meteorological ,society to take some action in the matter4 ,accordingly1 at a ,meeting of the ,council of the ,meteorological ,society1 held on #aeth of ,may1 #ahgh1 it was resolved-- #8,that the ,house ,committee be instructed to address the following ,societies3-- ,,the ,,royal ,,institute ,,of ,,british ,,architects1 ,,the ,,physical ,,society1 ,,the ,,society ,,of ,,telegraph ,,engineers1 asking them to name delegates to co-operate in considering the desirability or otherwise of issuing a code of rules for the erection of lightning conductors1 and to proceed in preparing a code if it is thought desirable4' ,in accordance with this resolution the following letter was addressed to the ,secretaries of the above ,societies3-- ,,the ,,meteorological ,,society1 #cj1 ,,great ,,george ,,street1 ,,westminster1 ,june #ad1 #ahgh4 ,,sir1 ,the ,council of the ,meteorological ,society have had under their consideration for some time the possibility of formulating the existing knowledge on the subject of the protection of property from damage by electricity1 and the advisability of preparing and issuing a general code of rules for the erection of lightning conductors4 ,they are of opinion that this would best be done by a joint committee of representative members of those ,societies before which such subjects most naturally come2 and they have1 therefore1 decided upon inviting the co-operation of your ,society by the nomination of one or more delegates to join a ,committee by whom the whole question should be considered1 and to whom also any written communications would be submitted4 ,the ,council trust that your ,society may be represented by delegates2 but if that course be impossible1 they invite any written suggestions which you may have to offer4 ,a meeting of the delegates will be called for an early date after the receipt from the ,societies consulted1 of the names of the gentlemen nominated by each4 ,we are1 ,sir1 ,your obedient servants1 ,g4 ,j4 ,,symons1 ,,john ,w4 ,,tripe1 ,hon4 ,secretaries4 ,in reply to this circular all the societies invited nominated delegates1 and the ,conference was constituted as follows3-- ,meteorological ,society4 ,c4 ,,brooke1 ,f4,r4,s41 ,past ,president4 ,e4 ,e4 ,,dymond1 ,f4,m4,s4 ,g4 ,j4 ,,symons1 ,f4,r4,s41 ,secretary4 ,royal ,institute of ,british ,,prof4 ,,lewis1 ,f4,s4,a4 ,architects4 ,j4 ,,whichcord1 ,f4,s4,a41 ,vice ,president4 ,society of ,telegraph ,engineers and ,,latimer ,,clark1 ,m4 ,inst4 ,c4,e41 ,past of ,electricians4 ,president4 ,w4 ,h4 ,,preece1 ,f4,r4,s41 ,m4 ,inst4 ,c4,e41 ,vice ,president4 ,physical ,society4 ,,prof4 ,w4 ,g4 ,,adams1 ,f4,r4,s41 ,president4 ,,prof4 ,g4 ,,carey ,,foster1 ,f4,r4,s41 ,past ,president4 ,the steps taken by the delegates will be best explained by a short narrative chiefly formed of extracts from the minute book of the ,conference4 ,the first meeting was held at the rooms of the ,meteorological ,society1 on ,november #adth1 #ahgh1 when all the delegates were present4 ,mr4 ,c4 ,brooke1 ,f4,r4,s41 was appointed ,president of the ,conference1 and ,mr4 ,g4 ,j4 ,symons1 ,f4,r4,s41 ,secretary4 ,professor ,w4 ,e4 ,ayrton was elected a member4 ,a circular1 which will be found in ,appendix ,a1 was drafted for issue to manufacturers of lightning conductors4 ,this was sent to sixty-five firms1 but only eight replied1 and their answers are printed verbatim in the same ,appendix4 ,an analysis of the replies forms ,appendix ,b4 ,appendix ,c is a reply received too late for insertion in ,appendix ,a1 and after ,mr4 ,preece had compiled ,appendix ,b4 ,another reply from an ,american firm will be found in ,appendix ,i1 p4 7#aib71 making ten in all4 ,at a subsequent meeting1 the delegates from the ,royal ,institute of ,british ,architects were requested to ask the ,council of that body to issue a circular to their members inviting them to furnish information respecting buildings injured by lightning4 ,this circular1 together with abstracts of the replies1 and a brief ,introductory ,summary1 by ,messrs4 ,lewis and ,whichcord1 will be found in ,appendix ,d4 ,mr4 ,symons submitted to the meeting a mass of statistics respecting accidents by lightning which he had collected in the years #aheg-ei2 they were referred to ,professor ,ayrton1 and his note upon them constitutes ,appendix ,e4 ,at the meeting on ,august #eth1 #ahgi1 the ,secretary announced the death of the ,president of the ,conference1 ,mr4 ,c4 ,brooke1 ,f4,r4,s41 a vote of condolence was passed unanimously1 and ordered to be forwarded to ,mrs4 ,brooke4 ,the ,conference then proceeded to elect a new ,chairman1 and it was unanimously resolved that ,professor ,w4 ,g4 ,adams1 ,f4,r4,s41 be requested to accept the office4 ,the following circular was approved and ordered to be forwarded to a large number of the most important newspapers and periodicals throughout the ,united ,kingdom4 ,,lightning ,,conductors4 ,to the ,editor of ---- ,,sir1-- ,in the summer of #ahgh delegates were nominated by the following ,societies1 viz41 the ,royal ,institute of ,british ,architects1 the ,society of ,telegraph ,engineers1 the ,physical ,society1 and the ,meteorological ,society1 for the following purpose3-- 8,to consider the possibility of formulating the existing knowledge on the subject of the protection of property from damage by electricity1 and the advisability of preparing and issuing a general code of rules for the erection of ,lightning ,conductors40 ,the delegates have held several meetings1 and have already collected1 firstly1 from the manufacturers of ,lightning ,conductors1 and secondly1 from the ,members of the ,royal ,institute of ,british ,architects1 a large amount of thoroughly practical information4 ,several of their number are also engaged in forming abstracts of the salient features of the literature of the subject4 ,the ,members of the ,conference are1 however1 most anxious that their ,report should be as trustworthy and as exhaustive as possible1 and they have1 therefore1 instructed me to ask you to assist them by publishing this epitome of their proceedings1 and allowing them to invite correspondence upon the points mentioned below4 ,i am1 ,sir1 ,your obedient servant1 ,g4 ,j4 ,,symons1 ,f4,r4,s41 ,secretary to the ,conference4 ,,lightning ,,rod ,,conference1 #cj1 ,,great ,,george ,,street1 ,s4,w4 ,,class ,,of ,,facts ,,most ,,required4 ,full details of accidents by lightning1 stating especially whether the building struck had a conductor or not4 ,if there was a conductor1 state its dimensions--construction--mode of attachment to building--whether its top was pointed--distance of its upper terminal from the place struck--nature and extent of the connection between the conductor and the earth1 and whether the earth was dry or moist--whether the conductor was itself injured--and whether the conductor or the point struck was the most salient object in the vicinity4 ,information is also desired1 either verbally or by sketches1 as to the position of metal spouting and lead roofing relatively to the point struck1 and to the conductor4 ,details of the thickest piece of metal melted by a flash of lightning are much needed4 ,unimpeachable evidence of the failure of conductors is much desired1 as such failures would be extremely instructive4 ,the replies were by no means as numerous as was expected3 the most important will be found in ,appendix ,i4 ,at the meeting1 ,october #bgth1 #ahgi1 it was resolved 8,that the members of the ,conference will undertake to prepare abstracts of the principal ,english and ,foreign books upon ,lightning ,conductors40 ,this work became extremely heavy1 and occupied much time1 as will be seen from ,appendix ,f1 which contains abstracts of sixty separate treatises1 of which #bf are from ,english1 #ag from ,french1 #f from ,belgian1 #e from ,american1 and #e from ,german authors1 and one is from the ,norwegian4 ,in order to guard against omitting important works1 it was resolved 8,that application be made to the ,society of ,telegraph ,engineers for advance sheets of the ,ronalds ,catalogue40 ,from it1 supplemented by ,mr4 ,latimer ,clark's and other lists1 the ,secretary compiled ,appendix ,g41 which contains the full titles of no fewer than #gjd separate works upon lightning conductors1 or on subjects intimately connected therewith4 ,at the same meeting it was resolved that efforts be made to obtain a set of the official instructions issued in all foreign countries4 ,the circular issued1 and an abstract of the information collected1 including replies from ,america1 ,belgium1 ,denmark1 ,germany1 ,holland1 ,india1 ,italy1 and ,norway1 will be found in ,appendix ,h4 ,full details respecting the practice in ,france will be found in ,appendices ,f1 ,k1 and ,l1 and a notice of ,zenger's ,austrian system1 on p4 7#ajd74 ,at the meeting1 ,nov4 #bjth1 #ahgi1 the ,secretary was unanimously requested to act as ,editor of the ,report4 ,at the meeting1 ,jan4 #bbnd1 #ahhj1 a letter was received from ,mr4 ,r4 ,h4 ,scott1 ,f4,r4,s41 ,secretary to the ,meteorological ,council1 enclosing a report respecting the injury to the 8,southern ,queen10 it was resolved1 8,that some of the delegates visit the ship40 ,the report and a note of the results of the visit will be found in ,appendix ,i page 7#bje74 ,at the meeting1 ,april #aeth1 #ahhj1 ,prof4 ,d4 ,e4 ,hughes was unanimously elected member of the ,conference4 ,at the meeting1 ,july #fth1 #ahhj1 the ,secretary handed in a sketch of a house with various parts of the lightning conductor marked upon it1 and obtained from the delegates definite names for each portion1 in order that in framing the report there might be no uncertainty as to what was meant by any special term1 great confusion in this respect having previously existed4 ,the terms adopted have been3 ,conductor4--,the whole arrangement for the protection of a building4 ,point4--,the upper termination of the conductor1 whether blunt or sharp1 single or bifurcated4 ,upper terminal4--,that portion of the conductor which is between the top of the edifice and the point4 ,joint4--,any connection between any two parts of the conductor4 ,rod4--,the main portion of the conductor1 whether it consist of rope1 tape1 tube or solid rod4 ,circuit des ,fates4--,a rod running round the eaves of a house1 the battlements of a tower1 c4 ,earth plate4--,the termination of the conductor in the ground1 the pattern being indicated by special terms4 ,the accompanying lithograph will1 it is hoped1 supply all additional necessary particulars4 ,it is desirable to state that the illustrations in this ,report have been prepared by ,mr4 ,e4 ,white ,wallis1 ,f4,m4,s41 so as to bring out the various features distinctly1 and as nearly as possible in true proportion1 but without any attempt at artistic finish4 ,the meetings during the latter part of #ahhj1 and the early part of #ahha1 were devoted chiefly to the discussion of various questions as bases for the report4 ,much time was also occupied in perfecting the various appendices1 and in compiling an exhaustive index to them4 ,in ,may1 #ahha1 ,messrs4 ,preece and ,symons1 being in ,paris1 made careful enquiries as to the existing practice in ,france respecting lightning conductors4 ,their notes form ,appendix ,k4 ,at the meeting held on ,may #bgth1 #ahha1 the ,secretary was instructed to draw up a draft report1 and this having been put in type was sent to all the delegates2 carefully considered1 revised1 and amended at various subsequent meetings1 and finally adopted4 ,illustration3 ,,index ,,sketch ,,of ,,lightning ,,conductor1 ,,illustrating ,,the ,,terms ,,employed ,,in ,,the ,,report4 ,,terms ,,applied ,,to ,,the ,,various ,,parts ,,of ,a ,,conductor4 ,crutch ,strap ,staple ,wall ,eye ,a ,point ,b ,upper ,terminal c ,joint ,d ,rod ,e ,ridge ,rod ,f ,circuit des fates ,g ,earth ,plates ,g#a ,earth ,plates ,sanderson ,g#b ,earth ,plates ,borrel ,g#c ,earth ,plates ,spang ,,report4 ,the ,delegates are of opinion that it will conduce to clearness of statement if their ,report be divided into three sections-- 7#a7 ,the purpose which a lightning conductor is intended to serve4 7#b7 ,a statement of those features in the construction and erection of lightning conductors respecting which there has been1 or is1 a difference of opinion1 and the final decision of the ,conference thereupon4 7#c7 ,code of rules for the erection of lightning conductors4 ,,section ,i4--,the purpose which a ,lightning ,conductor is intended to serve4 ,a flash of lightning is the passage of an electric spark between two bodies oppositely or unequally electrified1 and between which the difference of electric pressure or potential is sufficiently strong to break across the air space which separates them1 and to produce what is known as a disruptive discharge4 ,a flash may pass either between one cloud and another1 or between a cloud and the earth4 ,in the former case damage is not likely to be done1 in the latter damage is or is not done1 according to the point at or from which the lightning strikes4 ,the more any object projects above the general level1 the less is the distance between it and the cloud1 and as the less the distance the less the resistance offered to the discharge1 high objects are1 cteris paribus1 most frequently struck4 ,some substances1 such as copper or iron1 can conduct a large quantity of electricity with facility1 and are called good conductors4 ,other substances1 such as living vegetable or animal matter1 offer much obstruction1 and form only partial conductors2 while dry earth1 stone1 and wood almost entirely prevent the passage of electricity1 and are very bad conductors--in fact1 insulators4 ,for instance1 a man may with perfect impunity clasp a copper rod an inch in diameter1 the bottom of which is well connected with moist earth1 while the top of it receives a violent flash of lightning4 ,but if the electricity does not find a path prepared for it1 it will utilise such partial conductors as may be reasonably near1 for example--the heated air from a kitchen chimney1 the soot inside1 and then the metal range at the bottom2 here1 however1 stone or dry material is generally found1 which will not conduct it1 and then it dashes across the kitchen at some gas or water pipe1 or some pump or drain leading to damp earth1 doing serious damage on the way3 or it may meet some tree in its course and rend it from top to bottom1 and if the human body intervene life may be destroyed4 ,mechanical injury is inflicted only where the conduction for the discharge is imperfect4 ,a lightning conductor fulfils two functions3 it facilitates the discharge of the electricity to the earth1 so as to carry it off harmlessly1 and it tends to prevent disruptive discharge by silently neutralising the conditions which determine such discharge in the neighbourhood of the conductor4 ,to effect the first object a lightning conductor should offer a line of discharge more nearly perfect1 and more accessible1 than any other offered by the materials or contents of the edifice we wish to protect4 ,to effect the second object the conductor should be surmounted by a point or points4 ,fine points and flames have the property of slowly and silently dissipating the electrical charges2 they1 in fact1 act as safety valves4 ,if all these conditions be fulfilled2 if the points be high enough to be the most salient features of the building no matter from what direction the storm cloud may come1 be of ample dimensions and in thoroughly perfect electrical connection with the earth1 the edifice with all that it contains will be safe1 and the conductor might even be surrounded by gunpowder in the heaviest storm without risk or danger4 ,all accidents may be said to be due to a neglect of these simple elementary principles4 ,the most frequent sources of failure are conductors deficient either in number1 height1 or conductivity1 bad joints1 or bad earth connections4 ,there is no authentic case on record where a properly-constructed conductor failed to do its duty4 ,,section ,,ii4--,a ,statement of those features in the construction and erection of ,lightning ,conductors1 respecting which there has been1 or is1 a difference of opinion1 and the final decision of the ,conference thereupon4 ,points4 ,material for ,conductor4 ,size of ,rod4 ,shape of ,rod4 7,rods1 ,tubes1 ,tape1 ,rope1 ,plait47 ,joints4 ,protection of ,rod4 ,attachment to ,building4 ,earth ,plates4 ,space ,protected4 ,height of ,upper ,terminal4 ,testing ,conductors4 ,internal ,masses of ,metal4 ,external ,masses of ,metal4 ,,points4--,starting with the extreme top1 we have first to deal with the question of points4 ,the utility of points was hotly contested rather more than a century since1 and an abstract of the discussion will be found in ,appendix ,f1 page 7#gi71 and difference of opinion still exists as to their precise functions and value4 ,the decision as to the best form of points is complicated by two opposing requirements 7#a71 the sharper the point the more rapid the silent discharge of electricity1 and1 therefore1 the more effective the conductor2 but 7#b7 the sharper the point the more easily is it destroyed by oxidation1 or fused1 should a heavy disruptive discharge fall upon it4 ,attempts have been made by the use of gold1 silver1 and platinum1 to obtain a sharp point which should not only be durable1 but1 owing to its high melting point1 resist fusion by a disruptive discharge4 ,but such metals are very expensive1 and the statements in ,appendix ,f1 pages 7#fg1 #fi1 #gc1 #ajc1 #abc1 #abh1 and #aci7 prove that even platinum points are often damaged4 ,copper points whose sectional area is less than #je of a square inch are very liable to be melted4 ,lightning has even fused a copper rod #aj sq4 in4 in sectional area1 i4e41 #jce in4 in diameter1 and there are many rods still standing of which the extremity has been melted into a button or knob4 ,for these reasons it seems best to separate the double functions of the point1 prolonging the upper terminal to the very summit1 and merely bevelling it off1 so that1 if a disruptive discharge does take place1 the full conducting power of the rod may be ready to receive it1 and1 therefore1 that there may be no risk of melted particles of metal setting fire to the building1 as has occurred4 ,appendix ,f1 p4 7#ic74 ,at the same time1 having regard to the importance of silent discharge from sharp points1 we suggest that at one foot below the extreme top of the upper terminal there be firmly attached1 by screws and solder1 a copper ring1 bearing three or four copper needles1 each #f inches long and tapering from inch diameter to as fine a point as can be made2 and with the object of rendering the sharpness as permanent as possible1 we advise that they be platinized1 gilded1 or nickel plated4 ,vanes1 finials1 and ornamental ironwork so frequently form the upper portion of edifices1 that it is essential to consider their relation to the conductor4 ,they should always be in perfect metallic connection with the conductor4 ,the possibility of such metal work inducing the charge to desert the conductor for some other path is sometimes suggested1 but it could not happen unless the conductor were out of order1 e4g41 of inadequate conducting power1 or had an imperfect earth-contact4 ,with respect to factory chimneys1 a different practice prevails in ,england from that which is nearly universal on the ,continent4 ,in this country one straight rod is usually carried up on one side of the chimney to a height above the top about equal to the diameter of the chimney4 ,on the ,continent two arches of iron are put crosswise over the aperture of the chimney1 and a vertical rod is carried up from the intersection4 ,in both systems the upper terminal suffers from the corroding effect of the fumes from the chimney4 ,dr4 ,mann thought1 ,appendix ,f1 p4 7#acb71 that considering the ready path for lightning afforded by the heated smoke discharged from chimneys1 a coronal conductor should be placed upon them1 as well as a multiple point4 ,messrs4 ,gray say1 p4 7#i73 8,for high chimney shafts we fit a copper band round the top1 and four points thereon connected to main down rod40 ,the ,edinburgh ,gas ,works chimney1 #cda feet high and #ad feet across at the top1 was fitted with a conductor under the advice of ,faraday1 ,appendix ,f1 p4 7#hi74 ,it had an iron plate on the top2 ,faraday directed that the rod should be connected with this plate1 and the upper terminal should rise vertically #f feet above it4 ,we are of opinion that a coronal or copper band1 with stout copper points1 each about #a ft4 long1 at intervals of #b or #c ft4 throughout the circumference1 will make the most durable and generally useful protector for a factory chimney1 but these points should be gilded or otherwise protected against corrosion4 ,,material ,,for ,,conductor4--,iron and copper are practically the only two metals which need consideration2 brass1 which has sometimes been used is so perishable that its employment is a self-evident error4 ,we will assume the conductivity of equal lengths and weights of iron to be1 in the case of steady currents of electricity1 th that of copper1 and the cost of iron to be th that of copper1 this would make the cost of copper for equal conducting power #ifths1 or #ej per cent4 dearer than iron4 ,but there are other matters to be considered3 7#a7 the great weight and bulk of iron rods2 7#b7 their deterioration by rust2 7#c7 the serious obstruction offered by a rusty joint2 7#d7 the suddenness of lightning discharge which modifies the conductivity2 and lastly1 that iron is so much more rigid than copper that 7except in the form of iron wire rope1 of which we shall speak hereafter7 it can rarely be used in greater lengths than #bj feet1 and thus numerous joints become necessary1 whereas every needless joint should be avoided4 ,as regards galvanizing1 we think it scarcely judicious to trust entirely to it for protection against oxidation1 for many instances of imperfect galvanizing have come to our knowledge4 ,on the other hand copper becomes brittle1 not only when exposed to the air1 but also by the passage through it of powerful charges of atmospheric electricity4 ,franklin used iron1 and it is employed in ,america and on the ,continent much more generally than copper1 and it is less tempting to the thief4 ,nevertheless1 as the cost of erection bears a considerable ratio to the cost of the rod itself1 and as iron possesses the disadvantages above stated1 we think that in all ordinary cases a copper rod will in the end prove the cheapest1 as it will certainly be the most durable4 ,,size ,,of ,,rod4--,this is perhaps the most difficult subject which has to be determined4 ,we greatly regret the shortness of ,table ,i4 in ,appendix ,k2 but we think that it must be assumed from it that lightning has fused a copper rod #aj in4 7th7 in area1 i4e41 weighing #f ounces to the foot4 ,we have also the ,caterham case1 ,appendix ,i1 p4 7#bad71 where a copper tube weighing #e ounces per foot was heated to redness4 ,the saving of cost which might be effected by using1 for very low buildings1 rather slighter rods than for ordinary edifices is not worth considering4 ,in a #cj feet rod it could hardly amount to #ajs4 ,we therefore recommend as the minimum to be used3-- ,material4 ,pattern4 ,diameter4 ,sectional ,area of ,metal4 ,weight per foot4 in4 sq4 in4 ,copper ,rope #aj #f oz4 ,copper ,round ,rod #aa #g oz4 ,copper ,tape #ji #f oz4 ,iron ,round ,rod #i_/aj #fd #ce oz4 ,,shape ,,of ,,rod4--,this depends upon a subject which until lately was warmly discussed1 viz41 upon the relative importance of the sectional area1 and of the superficial area of a conductor2 a matter which has been the subject of active discussion among electrical authorities4 ,faraday and ,sir ,w4 ,snow ,harris1 for example1 held diametrically opposite views respecting it4 ,appendix ,f1 p4 7#hi71 and ,i1 p4 7#aie74 ,there is abundant and conclusive evidence that in the case of steady electric currents1 conductivity depends upon sectional area alone1 and not at all upon extent of surface1 and experiments by ,mr4 ,preece and ,dr4 ,warren ,de la ,rue tend to show that1 in the case of sudden discharges from condensers1 to which lightning discharges are probably analogous1 the influence of form is not considerable4 ,on the other hand1 there is equally conclusive evidence that the facility with which currents of short duration pass through conductors is affected by the form and arrangement1 as well as by the sectional area of the conductors4 ,upon the whole we agree with the opinion quoted below1 from a writer recognized in the ,united ,states as a high authority on lightning conductors1 who1 after describing and engraving more than fifty patterns of rods1 says#a3-- ,footnote #a3 ,spang1 8,a ,practical ,treatise on ,lightning ,protection10 p4 #aba4 8,the alleged improvements in the said conductors are1 in nearly all cases1 worthless1 or of a trifling and unimportant character4 ,the fact is1 the said conductors are quite inferior1 and contain no essential improvement upon the ordinary round iron rod used during the days of ,franklin40 ,in ,europe the only forms at all generally employed are3-- ,rods 7round or square72 ,tubes2 ,tape2 ,ropes 7wire1 or wire with hemp centres72 ,plait4 ,rods 7round or square74--,the advantages and disadvantages of rods are easily stated4 ,the advantages are their durability and their rigidity1 the latter being of importance for long upper terminals4 ,the disadvantages are the necessity for numerous joints1 and the difficulty of avoiding serious disfigurement to the building to which they are attached4 ,tubes have much the same merits and demerits1 with the additional objection that they are necessarily of larger diameter than solid rods1 and therefore more conspicuous4 ,they have also an additional disadvantage in that they are generally joined together by screw collars4 ,the cutting of the thread in the tube seriously diminishes the sectional area1 and the joint so made is electrically defective4 ,if tubes are used1 the joints should be made as directed in the code of rules under the head of joints4 ,tape is a form of rod which is of comparatively recent introduction1 and possesses many advantages4 ,foremost among these is the length which can be supplied in a single piece4 ,where1 as at the junction with an upper terminal1 a joint is needed1 it is easily made by clamping or rivetting the two surfaces together and then imbedding the whole in a mass of solder4 ,no kind of coupling known to us is1 in our opinion1 equal to this very simple one4 ,owing to the flexibility of the tape it can be made to follow closely the outlines of a building1 or may be countersunk in it1 and painted over1 but1 as stated further on1 abrupt bends should be avoided1 and the precautions and instruction set forth on page #ah should be followed4 ,the objections to tape1 ,appendix ,a1 pages 7#e7 and 7#af7 will be found to be objections1 not to tape per se1 but to bad practice on the part of some persons who have fitted it up and availed themselves unduly of its flexibility4 ,ropes4--,for many years past rope constructed of twisted strands of copper or of iron wires has been largely employed for lightning rods4 ,there is on record a very remarkable case of the complete destruction of a brass wire rope1 an event which1 if it had been repeated1 might justly have been regarded as a serious objection to the use of ropes4 ,this case is fully reported in ,appendix ,f1 pages 7#fb-fc72 and from it some ,french electricians have concluded that lightning may single out some wires from a rope and travel along them in preference to the rest1 even when the whole of them are hardly sufficient to give it a free passage4 ,whatever may have been the explanation1 this accident seems to be unique1 and even if we accept the explanation given1 the only extra precaution which it calls for1 is the soldering of each extremity of the several wires forming the rod1 and at every joint1 into a single mass4 ,we agree with ,m4 ,borrel in thinking that serious evil arises from using wire of too small diameter1 which involves an additional number of interstices for the lodgement of dirt1 smoke1 and water1 and at the same time renders the wires too thin effectually to resist oxidation4 ,we have had before us rope in4 in diameter1 composed of #di strands of a copper wire about ,no4 #ai ,b4,w4,g41 say #jjd in4 in diameter4 ,on the contrary1 one firm speaks of employing ,no4 #aj ,b4,w4,g41 i4e4 #jad in4 diameter1 and in special cases ,nos4 #h and even #g1 which would be about #jag in4 and #jai in4 diameter respectively3 these would not be open to the objection we have raised4 ,the objection to thin wires is necessarily greater with iron ropes1 even if galvanized1 than with copper1 for irrespective of the doubt as to the perfect galvanizing of every part1 there is the greater brittleness1 and consequent risk of damage from defective continuity4 ,ropes with ,hemp ,centres4--,one ,english firm sent us a specimen of #f-strand copper rope with a hemp core1 and we understand that the same pattern is occasionally used both in iron and copper in ,france4 ,we do not know the precise object aimed at--probably flexibility--but considering the perishableness of such a core1 its variation in length with the hygrometric state of the air1 and its invariability when the copper is varying with temperature1 we cannot regard it as a wise construction4 ,plait4--,this form of rod was probably designed in the belief that the essential element in a lightning rod was plenty of surface4 ,it is made in two sizes1 with copper wire1 about ,no4 #af ,b4,w4,g41 plaited into a sort of ribbon4 ,it invites oxidation as much as is possible1 and is in our opinion neither durable nor trustworthy4 ,the original form of this rod was ridiculously bad2 for it consisted of #ac copper wires and #a zinc one4 ,every time that it became wet1 feeble electric action was set up1 and the zinc wire was gradually destroyed1 without the slightest benefit to anybody4 ,,joints4--,the most fruitful sources of danger in rods are bad joints1 not necessarily those that are mechanically bad1 but those that are so electrically4 ,a joint is said to be electrically bad when it offers resistance to the passage of electricity through it4 ,there should be no resistance whatever4 ,a careful inspection by ,capt4 ,bucknill1 ,r4,e4 7,appendix ,m1 p4 #bdc71 has proved that bad joints in lightning rods are very abundant1 though they appear perfectly sound2 and everyone who has measured the electrical condition of conductors confirms this fact4 ,bad joints have the same effect as lengthening the conductor2 and1 in one case1 one bad joint was found to have the same effect on a discharge of electricity as a conductor #a1ijj miles long4 ,it is evident that such rods may be worse than useless1 for other parts of the building may offer easier paths for the discharge to the earth4 ,if the joint be imperfect1 and the rod convey a charge to earth1 heat will be generated at the joint1 the rod may be fused1 and the discharge be diverted to the building4 ,screwed1 scarfed1 and rivetted joints1 however well they may be made mechanically1 are certain to rust and corrode in time1 owing to the expansions and contractions due to changes of temperature admitting moisture1 and thus causing corrosion and resistance4 ,no joint can possibly be electrically perfect that is not metallically continuous1 and careful soldering1 in addition to screwing1 scarfing1 or rivetting1 is the only certain mode of securing this4 ,soldering is a method that has borne the test of experience1 and its success as a means of securing perfect joints leaves no excuse for its omission4 ,the fewer joints the better1 but where there are joints they can only be made electrically secure by careful soldering4 ,,protection ,,of ,,rod4--,the lower part of copper rods is sometimes stolen for the sake of the metal4 ,this can be guarded against by putting it inside a length of iron gas-barrel1 extending from some distance below ground to #aj ft4 above it4 ,,painting4--,iron conductors1 even if they are galvanized1 should be painted throughout1 except at the points1 which should be gilded or nickel-plated4 ,in ,france and ,belgium painting is resorted to to a considerable extent1 and the practice was recommended by the late ,professor ,joseph ,henry1 and followed very largely in ,america4 ,appendix ,f1 pages 7#ii7 and 7#aac74 ,,attachment ,,to ,,buildings4--,the evidence against the use of glass or other material in order to insulate the conductor1 is overwhelming1 and insulation may be regarded as unnecessary and mischievous4 ,the essentials are 7#a7 that the rod be attached to the building by fastenings of the same metal as itself1 7#b7 that the fastenings be of adequate strength1 7#c7 that they be of such form as not to compress or distort the rod1 7#d7 that they allow play for its expansion and contraction1 7#e7 that they hold it firmly enough to prevent all the weight falling on any one bearing4 ,where practicable it is well to take the rod down that face of the house which is most exposed to rain4 ,,earth ,,plates4--,this portion of the lightning conductor is of the utmost importance1 but has hitherto been the most neglected4 ,the majority of cases in which lightning has caused injury very near to or upon conductors are traceable to those conductors having imperfect earth terminals4 ,we know of many cases in which the earth terminals have been miserably imperfect1 or entirely neglected1 when the above-ground portion has been perfectly satisfactory4 ,in fact1 though it may be admitted that the case found by ,dr4 ,mann1#b of the lightning rod of a church tower1 the lower end of which was thrust into an empty glass bottle1 is an exceptionally bad one2 yet there are sadly too many1 of which the ,middlesboro' case1 ,appendix ,i1 page 7#bag7 is a perfectly fair type4 ,footnote #b3 ,quarterly ,journ4 ,met4 ,soc41 ,vol4 ,,ii41 p4 #dbj4 ,a convenient earth connection is often afforded in towns by the iron mains for gas and water--arguments both for and against the utilisation of both water and gas mains will be found in the ,appendix--we1 therefore1 need only state our opinion in favour of connection with both4 ,but no connection should ever be made with soft metal pipes1 because of the risk of their fusion2 and the conductor should be kept as far as possible from internal gas pipes on account of the risk of lighting the gas at an imperfect joint4 ,as a general rule we advise the soldering of a plate of metal1 copper to copper1 iron to iron1 to the lower end of the conductor4 ,the earth plate should always be of the same metal as the rod1 otherwise destructive galvanic action sets in4 ,this plate1 which may be flat or cylindrical1 must not have less surface than #ah square feet1 i4e41 #i square feet on each face2 there is no advantage in notching or pointing it4 ,a hole must be dug1 or well sunk1 to receive this plate1 and the hole must be so deep that the earth surrounding the plate shall never be dry4 ,any available drain or other water should be allowed to soak into the earth1 over the site of the plate4 ,after the hole has been dug1 and the plate lowered into position1 it should be filled with cinders1 or coke4 ,in extremely dry rocky localities1 it is sometimes impossible to fulfil these conditions3 then the best thing to do is to bury three or four hundredweight of iron at the foot of the conductor1 still using the earth plate and the coke1 and taking especial care that the rain-water and sink pipes discharge over it4 ,all drains1 water-courses1 in fact1 everything which will assist in distributing the charge over a large extent of moist earth should be utilized by leading branches from the earth plate to them1 or a long length of the rod may be laid in a drain if it be one which will be constantly wet4 ,,space ,,protected4--,the question as to the extent of the space which will probably be protected by a lightning rod is one which is of very great practical importance1 because it governs the number and height of the upper terminals which are required for the protection of any given building4 ,the index to the ,appendix shows that 8,protection1 ,area of10 is discussed upon twenty-nine pages in different parts of the ,appendix4 ,it has been laid down that the space protected was a cone1 having the point for its apex1 and a base whose radius was equal to twice the height of the point1 while the latest ,french official instructions1 ,appendix ,f1 p4 7#fg71 state that a point will 8effectively protect a cone having the point for its apex1 and a base whose radius is #age of its height40 ,the ,english ,war ,department instructions considerably reduce this space by asserting1 ,appendix ,f1 p4 7#ga71 that 8no precise limit can be fixed to the protecting power of conductors4 ,in ,england the base of the protected cone is usually assumed to have a radius equal to the height from the ground2 but though this may be sufficiently correct for practical purposes1 it cannot always be relied upon40#c ,footnote #c3 ,on page 7#if7 two instances are recorded in which1 if the evidence can be trusted1 the stroke fell within a radius equal to the height1 but it is only right to say that the facts are not very clearly recorded4 ,illustration3 ,sketch illustrative of area of protection ,according to this rule1 the church of ,ste4 ,croix 7see ,appendix ,f1 p4 7#ada771 would require four upper terminals1 one on steeple1 one on chancel1 and one in the middle of each half of the transept4 ,from theoretical considerations stated by ,mr4 ,preece1 ,appendix ,f1 p4 7#acg71 he arrives at the conclusion that 8,a lightning rod protects a conic space whose height is the length of the rod1 whose base is a circle having its radius equal to the height of the rod1 and whose side is the quadrant of a circle1 whose radius is equal to the height of the rod40 ,at present we have not sufficient data to enable us theoretically to calculate the space protected by a lightning rod1 and therefore we are compelled to draw up our rules upon the question entirely from experience1 and here we find1 that with the doubtful exceptions already mentioned1 there is no recorded instance of a building being struck by lightning within a conical space1 the radius of whose base was equal to its height1 and we think that the adoption of this rule may reasonably be expected to yield that security in the future1 which as far as we know1 it has done in the past4 ,,height ,,of ,,upper ,,terminal4--,this matter is one which may be left entirely to the option of individual architects and engineers1 subject1 of course1 to the opinions expressed under the heading 8,space ,protected40 ,in ,france extremely long tiges1 or upper terminals1 generally #cc feet long1 are used2 but it is obvious that they are necessarily very strong and heavy1 and both by their weight and by the great leverage which they exert when there is any wind1 they must produce serious vibrations in the roof4 ,in ,england hitherto the opposite error is almost universal1 and we seldom see a conductor carried high enough to protect all the building to which it is attached4 ,the question of appearance comes in here1 but concerning it we need only remark that while in ,england care seems generally taken to conceal the conductors1 in ,france they are1 to a certain extent1 made features of the edifice4 ,with a proper exercise of taste1 the terminals of the lightning conductors can be made to assist the ornamentation of the building1 as has been done in many cases4 ,,testing ,,conductors4--,periodical examination and careful testing of the lightning conductor are requisite to maintain the system in efficient order4 ,points will corrode from oxidation and fusion2 joints will get loose and bad through the action of weather and workmen2 connections will decay both above and below ground2 imperfections will develope themselves2 alterations will be made by landlords and tenants2 and1 in spite of every precaution during erection1 the conductor will thus lose its efficiency if it be not maintained in thorough order4 ,for this purpose inspection should be both visual and electrical4 ,in order to facilitate the electrical examination of the conductor1 some firms have erected a double rod1 connected with one upper terminal1 one on each side of a chimney or shaft2 this is a very efficient arrangement1 for it provides a means for testing from the ground4 ,it has also been proposed to carry an insulated wire alongside or even within the rod1 connected to the terminal at the top1 and to the testing apparatus at the bottom4 ,a testing apparatus has been devised by ,mr4 ,anderson 7,lightning ,conductors1 p4 #fj74 ,m4 ,borrell1 ,appendix ,k1 p4 7#bbf71 ,captain ,bucknill1 ,r4,e41 ,appendix ,m1 p4 7#bdd71 and ,mr4 ,vyle1 ,appendix ,m1 p4 7#bdd71 have also introduced apparatus for the purpose4 ,the system in use in ,paris1 ,appendix ,k1 p4 7#bbe71 and ,m1 p4 7#bde71 is perhaps the simplest and cheapest1 and is effective as regards testing the efficiency of the conductor1 but not that of the earth connection4 ,the efficiency both of the conductor and of its earth terminal should be annually tested4 ,as this testing involves some skill and familiarity with electrical apparatus it would be advantageous if some competent person were officially appointed1 either by the government or by some recognised authority1 to perform this duty4 ,,internal ,,masses ,,of ,,metal4--,all large and long masses of metal1 such as beams1 girders1 pipes1 hot water systems1 and large ventilators fixed in the interior of buildings1 should be electrically connected with the earth1 or with the conductor2 but the soft metal gas pipes should never be used as conductors4 ,the inlet and outlet pipes of large meters should always be1 independently of the meter1 electrically connected with each other1 for two remarkable cases of the explosion of a meter have occurred through the presence of a joint in the pipe electrically bad owing to the use of ,india-rubber packing4 ,appendix ,m1 p4 7#bci74 ,,external ,,masses ,,of ,,metal4--,large constructive and decorative ironwork1 such as guttering1 flashings1 railings1 finials1 vanes1 c41 and all masses of metals used in building1 should be connected to each other1 and to the earth direct1 or to the conductor4 ,in fact1 the gutters and water pipes are already frequently utilized as a partially protective system4 ,the ventilators of soil pipes may also be employed in this way1 and even made sightly by the addition of an ornamental finial fitted with points1 but care must be taken that the joints are metallic and not made with red lead or putty2 and it must not be forgotten that the conductivity of lead is very small1 so that undue reliance must not be placed upon pipes made of that metal4 ,,section ,,iii4--,code of ,rules for the ,erection of ,lightning ,conductors4 ,the following ,code of ,rules should be carefully attended to in drawing out a specification for a ,lightning ,conductor1 the reasons for each being given in the previous ,sections and in the ,appendix3-- ,points4--,the point of the upper terminal should not be sharp1 not sharper than a cone of which the height is equal to the radius of its base4 ,but a foot lower down a copper ring should be screwed and soldered on to the upper terminal1 in which ring should be fixed three or four sharp copper points1 each about #f in4 long4 ,it is desirable that these points be so platinized1 gilded1 or nickel plated as to resist oxidation4 ,upper ,terminals4--,the number of conductors or points to be specified will depend upon the size of the building1 the material of which it is constructed1 and the comparative height of the several parts4 ,no general rule can be given for this2 but the architect must be guided by the directions given at pp4 #ab to #ad4 ,he must1 however1 bear in mind that even ordinary chimney stacks1 when exposed1 should be protected by short terminals connected to the nearest rod1 inasmuch as accidents often occur owing to the good conducting power of the heated air and soot in a chimney 7p4 #b74 ,insulators4--,the rod is not to be kept from the building by glass or other insulators1 but attached to it by metal fastenings4 7,see p4 #aa47 ,fixing4--,rods should preferentially be taken down the side of the building which is most exposed to rain4 ,they should be held firmly1 but the holdfasts should not be driven in so tightly as to pinch the rod1 or prevent the contraction and expansion produced by changes of temperature4 ,factory ,chimneys4--,these should have a copper band round the top1 and stout1 sharp1 copper points1 each about #a ft4 long1 at intervals of two or three feet throughout the circumference1 and the rod should be connected with all bands and metallic masses in or near the chimney4 7,see p4 #e47 ,oxidation of the points must be carefully guarded against4 ,ornamental ,ironwork4--,all vanes1 finials1 ridge ironwork1 c41 should be connected with the conductor1 and it is not absolutely necessary to use any other point than that afforded by such ornamental ironwork1 provided the connection be perfect and the mass of ironwork considerable4 ,as1 however1 there is risk of derangement through repairs1 it is safer to have an independent upper terminal4 7,see p4 #d47 ,material for ,rod4--,copper1 weighing not less than #f oz4 per foot run1 and the conductivity of which is not less than #ij per cent4 of that of pure copper1 either in the form of tape or rope of stout wires--no individual wire being less than ,no4 #ab ,b4 ,w4 ,g4 ,iron may be used1 but should not weigh less than #b lbs4 per foot run4 7,see pp4 #e to #aj47 ,joints4--,although electricity of high tension will jump across bad joints1 they diminish the efficacy of the conductor2 therefore every joint1 besides being well cleaned1 screwed1 scarfed1 or rivetted1 should be thoroughly soldered4 7,see p4 #aj47 ,protection4--,copper rods to the height of #aj feet above the ground should be protected from injury and theft1 by being enclosed in an iron pipe reaching some distance into the ground4 ,painting4--,iron rods1 whether galvanized or not1 should be painted2 copper ones may be painted or not according to architectural requirements4 ,curvature4--,the rod should not be bent abruptly round sharp corners4 ,in no case should the length of the rod between two points be more than half as long again as the straight line joining them4 ,where a string course or other projecting stone work will admit of it1 the rod may be carried straight through1 instead of round the projection4 ,in such a case the hole should be large enough to allow the conductor to pass freely1 and allow for expansion1 c4 ,extensive ,masses of ,metal4--,as far as practicable it is desirable that the conductor be connected to extensive masses of metal1 such as hot-water pipes1 c41 both internal and external2 but it should be kept away from all soft metal pipes1 and from internal gas-pipes of every kind1 respecting which see page #ae4 ,church ,bells inside well protected spires need not be connected4 ,earth ,connection4--,it is essential that the lower extremity of the conductor be buried in permanently damp soil2 hence proximity to rain-water pipes1 and to drains1 is desirable4 ,it is a very good plan to make the conductor bifurcate close below the surface of the ground1 and adopt two of the following methods for securing the escape of the lightning into the earth4 ,a strip of copper tape may be led from the bottom of the rod to the nearest gas or water main--not merely to a lead pipe--and be soldered to it2 or a tape may be soldered to a sheet of copper #c ft4 #c ft4 and #a_/af in4 thick1 buried in permanently wet earth1 and surrounded by cinders or coke2 or many yards of the tape may be laid in a trench filled with coke1 taking care that the surfaces of copper are1 as in the previous cases1 not less than #ah square feet4 ,where iron is used for the rod1 a galvanized iron plate of similar dimensions should be employed4 ,inspection4--,before giving his final certificate1 the architect should have the conductor satisfactorily examined and tested by a qualified person1 as injury to it often occurs up to the latest period of the works from accidental causes1 and often from the carelessness of workmen4 7,see p4 #ad47 ,collieries4--,undoubted evidence exists of the explosion of firedamp in collieries through sparks from atmospheric electricity being led into the mine by the wire ropes of the shaft and the iron rails of the galleries4 ,hence the headgear of all shafts should be protected by proper lightning conductors4 7,signed7 ,w4 ,,grylls ,,adams4 ,w4 ,e4 ,,ayrton4 ,,latimer ,,clark4 ,e4 ,e4 ,,dymond4 ,g4 ,,carey ,,foster4 ,d4 ,e4 ,,hughes4 ,t4 ,,hayter ,,lewis4 ,w4 ,h4 ,,preece4 ,g4 ,j4 ,,symons4 ,,john ,,whichcord4 ,december #adth1 #ahha4 ,,appendix ,a4 ,,circular ,,and ,,questions ,,issued ,,to ,manufacturers of ,lightning ,conductors1 ,,and ,,their ,,replies ,,thereto4 ,,note4--,there are only two points requiring mention respecting the following replies4 ,first1 that in order to avoid useless repetition of the questions1 the answers are numbered1 and the corresponding question will be found in the following circular4 ,secondly1 that the replies are verbatim1 as received from the manufacturers1 except that frequent entries will be found in square brackets1 e4g4 ,a #jaa in4 ,these represent approximately the sectional area of the conductors1 and are given to facilitate the comparison of the conducting capacities of the very various patterns submitted to the ,conference4 ,,circular4 ,,lightning ,,rod ,,conference4 #cj1 ,,great ,,george ,,street1 ,,westminster1 ,s4,w4 ,november #adth1 #ahgh4 ,at the invitation of the ,meteorological ,society delegates have been nominated by the following ,societies3 ,royal ,institute of ,british ,architects1 ,society of ,telegraph ,engineers1 ,physical ,society1 ,meteorological ,society1 to consider the present modes of erecting ,lightning conductors1 and improvements therein4 ,at a largely attended meeting held this day ,i was instructed to forward to you the questions stated below1 and to request you to forward with your replies any remarks which you may wish to lay before the ,conference4 ,if you desire any specimens to accompany your remarks1 ,i shall be glad if1 whenever possible1 they do not exceed five inches in length4 ,i am1 ,your obedient ,servant1 ,g4 ,j4 ,,symons1 ,secretary to the ,conference4 ,,questions4 7,it is requested that the replies be written on foolscap paper1 on one side only1 and that they be numbered in accordance with the questions47 #a4 ,form1 dimensions1 and material usually adopted by you for upper terminals4 #b4 ,material and dimensions of conductor4 #c4 ,is any definite proportion between the length and sectional area of the conductor observed1 and if any1 what8 #d4 ,joints1 how made4 #e4 ,attachment to building1 how made4 #f4 ,ground connection1 how formed1 and of what extent4 #g4 ,extent of area supposed to be protected4 #h4 ,if there is more than one terminal1 is the size of the conductor increased8 ,,replies4 #ci1 ,,wapping1 ,,london1 ,e4 #a4 ,the upper terminals are made of a copper tube inches in diameter and #a_/af inches thick ,a4 #jaa in4 ,in the upper end of the tube is fitted #ae inches of copper rod tapered to a point at the top1 into which is fixed #c or more smaller rods about inch in diameter ,a4 #jje in4 each tapered to a point1 and brought into the parent rod in a curve 7not at an angle74 ,the next part of the tube1 down to about #i inches from the bottom1 is filled with a stiff iron rod to strengthen it1 the lower end of the tube being left open to receive the rope4 ,this constitutes what is called 8the point40 ,these points vary in length from #b or #c to #h or #aj feet when used for buildings4 ,a square-topped tower would require a much higher point than would be necessary for the top of a spire4 ,sometimes the points are tipped with platinum1 which we consider to be altogether superfluous4 #b4 ,the conductor is simply a wire rope1 varying in size1 and mostly either 1 1 or inches in diameter ,a4 #jaa1 #jbj1 or #jca in4 ,these ropes are made in two different forms3 the one inch diameter ,a4 #jaa in41 most suitable for ships' use1 is composed of #di ,no4 #ah guage copper wires1 each wire having a circumferencial measurement of #aeg inches ,a4 #jjjb in42 the circumferencial or surface measurement of the whole of the #di wires is equal to #efic inches ,a4 #jaa in41 or say1 equal to the surface of a copper band #bhdf inches wide--i4e41 measuring both sides of the band4 ,the other make1 say inch diameter ,a4 #jbj in41 much used for lofty buildings1 is composed of #g ,no4 #g guage copper wires1 each wire having a circumferencial measurement of #eha inches ,a4 #jjbg in42 the circumferencial or surface measurement of the #g wires is equal to #djfg inches ,a4 #jai in41 or say equal to the surface of a copper band #bjcc inches wide4 #c4 ,there is no definite proportion observed between the length and sectional area of the conductor4 ,we take it that the sectional area should be the same1 irrespective of length1 as we do not trace that lightning varies in intensity while passing through a conductor of greater or less length4 ,the rather prevalent idea that a smaller conductor is sufficient for a low building is1 we think1 erroneous1 as we do not find any data to show that lightning in its descent loses any portion of its force until it actually enters the earth4 #d4 ,the copper rope is joined to the upper terminal by passing the end of the rope into the tube at the lower end of the terminal for the space of about #i inches1 and fixing it with #c copper rivets4 ,there is no other join in the conductor whatever--a feature of much greater importance than is sometimes admitted4 #e4 ,the upper terminal is passed through two strong earthenware insulators which are usually fixed to the building by two strong galvanized iron staples4 ,other modes of fixing the terminal must sometimes be resorted to1 as some factory chimneys are capped with iron1 and buildings of varied forms must be treated with according to circumstances4 ,having fixed the terminal1 the rope may then be led down the building on the most convenient side for the purpose1 and fixed at intervals of #f or #h ft41 according to circumstances1 with glass insulators supported by copper brackets4 ,the rope should be given the straightest course practicable from the upper point down to the earth1 carefully avoiding all angles1 specially an acute angle1 as much as possible1 and in its passage it should be kept clear from any other metal in the building4 ,there are three matters to which we would call special attention1 viz43 ,insulators1 ,angles and ,joints1 ,metal in ,building4 ,insulators4--,when copper rope lightning conductors were first introduced1 about the year #ahcg1 a circumstance occurred which at once proved the efficiency of the conductor1 and suggested the use of insulators4 ,the late ,mr4 ,andrew ,smith1 ,c4,e41 had fitted a factory chimney in the ,east of ,london with a rope conductor1 which was fixed to the chimney by iron staples4 ,in a violent storm which occurred soon afterwards1 the lightning was seen to pass down the conductor1 which remained unaltered in any way2 but on examining the chimney it was found that the brickwork had received a concussion at most1 if not all1 of the staples1 showing that the lightning in passing had expended part of its force on the iron staples4 ,it is probable that1 if the staples had been made of thicker iron1 and had been so placed as to lead off from the conductor with easy curves inwards1 instead of being driven into the wall at right angles with the conductor1 the concussions would have been much more violent than was the case4 ,angles and ,joints4--,it must be obvious to any one that lightning1 as well as any other matter or thing which travels at high speed1 would be greatly obstructed in having to turn corners4 ,it must also be borne in mind that lightning is of intense heat1 and while passing in a straight line the effect of its heat is lost in the velocity of its motion2 but in passing an angle its momentary pause 7much too brief to be calculated7 is sometimes enough to create sufficient heat to fuse the conductor at the angle4 ,for this reason all angles must be avoided1 and easy curves having a downward tendency substituted4 ,the angles in copper tube conductors are doubly objectionable1 for1 having joins as well as angles1 they are liable1 by the effect of heat1 to become disjointed4 ,it would be difficult1 if not impossible1 to fit a tubular conductor1 except in a straight line from end to end1 without this double objection4 ,similar objections apply also1 in a greater or less extent1 to the copper band conductors1 as they are made with joins1 and1 when fixed up1 are usually carried into and over as many angles as come in their way4 ,they do not so readily follow all the sinuosities of a building as a rope does on the curve principle4 ,the flat band conductors1 which are composed of a number of galvanized iron and copper wires combined1 are simply a frivolity4 ,metal in ,buildings4--,taking the conductivity of copper as from #g to #aj times greater than that of iron1 it would probably follow1 that if two rods1 the one of copper the other of iron1 in these proportionate sizes1 were brought together in one common terminal or point1 and led by the same course to the earth1 as much of the fluid would possibly pass down the one as the other4 ,on this principle1 we avoid contiguity with any metal in a building1 especially if in large masses1 such as machinery1 c4 ,ships' ,conductors4--,in fitting the rope conductor to a ship's rigging it is only necessary to pass it through a hole in the truck1 so that the end may stand about #f inches above the truck4 ,it may be held up by a pin or key passed through the rope close over the truck1 and then carried down the topgallant backstay 7to which it should be tied at intervals with yarn7 to the gunwale1 where a sufficient length of the conductor should be kept in a coil to reach well down into the sea in any position of the ship4 ,in stormy weather the coil may be untied1 and by its own weight the end will drop down into the sea as required4 ,sometimes the rope is shackled at the gunwale to a strip of sheet copper about #c inches wide1 which is nailed down the ship's side till it meets the sheathing at the bottom4 ,the strip of copper should overlay the sheathing for a few inches4 ,it may be noticed that this kind of conductor1 fitted with a coil at the gunwale1 is without any join whatever1 and that it takes almost a straight course direct from the truck into the water4 ,the copper band conductors let into the mast and carried through the hull of the ship are objectionable and unsafe1 as1 in passing from each portion of the mast1 they require moveable joints1 so as to admit the several parts of the mast being run up or down as required4 ,these joints present angular interruptions which may become out of order1 and1 in passing through the hull1 any rupture of the band in that part1 or the contiguity of other metals1 may cause serious consequences4 ,certainly1 there can be no necessity for carrying the lightning through the ship when1 by a safer and much more simple method1 it may be kept altogether outside4 ,in the smaller vessels1 where the mainmast is well above the other masts1 it may be sufficient for that mast only to be fitted with a conductor1 but in larger ships1 particularly long steam-ships1 where the masts are a considerable distance apart1 each mast should have a conductor4 ,we do not1 either in theory or in practice1 know any necessity for protecting the yards with conductors1 though it is not altogether improbable that1 in the absence of conductors on the masts1 the yards might get damaged while the masts remain uninjured4 #f4 ,the end of the rope should be buried in moist earth1 and carried in a curve to #e or #f feet from the foundation4 ,in clay ground and on the shady side of a building about #c feet below the surface would be deep enough2 but in lighter ground1 and particularly on the sunny side1 it should be buried #f or #g feet deep1 to ensure sufficient moisture at all times of the year4 #g4 ,as the course by which lightning approaches the earth is very devious1 it would be difficult to determine with certainty the extent of area protected2 but1 viewing the absence of damage to the most remote parts of the roofs of buildings which have been properly fitted with conductors within the last #dj years1 we should think the area protected may be taken as equal to from #c to #e or #f times the height of the conductor4 #h4 ,when two or more terminals are used1 the main rope should be somewhat enlarged2 otherwise1 the collective quantity of fluid received on the several points may be too great for the common channel4 ,,wilkins ,,weatherby4 99 99 99 99 99 ,,dora ,,street1 ,,limehouse1 ,e4 ,we have to own receipt of your valued communication of the #adth ult41 and with great pleasure to submit for the consideration of the ,conference the following replies to their questions4 ,we have endeavoured to make them as explicit as possible1 but it is difficult adequately to describe our system on paper1 and we suggest for the consideration of the ,conference the advisability of showing any ,committee they may appoint one or two of the numerous public buildings fitted by us4 ,any further particulars or drawings you may require we shall be glad to send you2 and it is with great pleasure that we add that any services we can render you in your valuable investigations are at your disposal4 #a4 ,a five-pointed copper spindle1 the sharp points of which are silvered1 and single points on high chimney shafts to the number of four or five4 #b4 ,copper solid bands1 or tubes1 8as samples sent10 being simple1 durable1 cheap1 and the most capacious form for the safe conduction of a heavy stroke of lightning1 the bands being from #a inch to #c inches in width and inch thick ,a4 #jab to #jcg in41 and the tubes from to #a inches in diameter and inch thick ,a4 #jbd to #jed in44 #c4 ,yes2 experience has proved that nothing less than #a inch bands ,a4 #jah in4 should be used for the main conductor to ordinary houses1 with ,a4 #jji in4 to #a inch ,a4 #jab in4 bands for branches1 and from #b to #c inches ,a4 #jbd to #jcg in4 bands as main conductor to buildings of large area1 with #a to #a inch ,a4 #jab to #jah in4 for branches2 or1 in the case of chimney shafts1 inch to #a inch tube ,a4 #jbd to ,o#ed in4 for main conductor1 and #b to #c inches flat band ,a4 #jbd to #jcg in4 for tops of same4 #d4 ,the bands are in long lengths1 are lapped1 closely rivetted and soldered1 to form a continuous band2 while the tubes have patent insertion joints1 the upper end being turned and fitted into the lower end1 which is bored1 and the tube then forms a continuous line externally and internally4 #e4 ,copper holdfasts to suit shape and size of conductor4 #f4 ,not less than #cj feet of #a inch to #b inch copper bands ,a4 ,o#ah to #jbd in4 in two or three branches1 with forks at end of each band1 and1 if water is not near1 the trenches half filled with carbonaceous materials and well watered1 as this material will readily absorb the least moisture and retain it1 while being in itself the best conductor4 ,but much will depend upon the nature of the ground2 for if chalk or rock foundation and water cannot be got at1 the ground branches must be at least doubled1 and the trenches deeper and made up of carbonaceous materials and earth4 #g4 ,our experience is that no appreciable extent is protected by a single rod conductor in the presence of other influences4 ,the chimney-stacks1 lined with carbon in the shape of soot1 with the heated gases1 cause a rarefaction in the atmosphere1 and form an easier passage for the electric fluid4 ,roofs and buildings having large masses of metals will be more likely to influence lightning than the single line of copper rod generally fitted4 ,many cases have occurred of chimney-stacks #d feet to #i feet across being struck opposite the conductor1 and lead roofs1 gutters1 lead ridges1 c41 from #aj feet to #bj feet from the rod conductor4 #h4 ,no2 the system of conduction used by us does away with this1 the lines of conduction being ample4 ,,remarks4 ,from our close connection with the late ,sir ,william ,snow ,harris1 adviser to the ,crown for upwards of twenty-five years in regard to lightning conductors for the navy1 and having made lightning conductors our especial practical study for thirty-five years1 we may be pardoned for making a few remarks on the protection of buildings from lightning4 ,we would1 firstly1 say that the system of conductors now fitted by us is based upon these past years of experience1 and upon facts collected during this period1 of accidents to buildings having the ordinary single line of conduction1 as also from the practical success of the conductors in the navy4 ,the form of conductors used by us has been adopted after considerable experience1 as being the most simple1 solid1 durable1 and capacious form of conductor for the safe conduction of heavy strokes of lightning4 ,in place of insulators as fastenings1 we use copper holdfasts1 as we found the former dangerous and useless1 as the glass1 being non-conductive1 the expansion and heat of the electric fluid1 being confined1 broke them1 and caused an unsafe concussion2 and it is also a disadvantage for a conductor to be away from the building1 as nearly every material in nature assists1 without detracting from1 the safe discharge of the electric fluid through a good copper conductor4 ,we find that the copper wire rope conductor1 usually applied1 is seldom more than th of an inch in diameter2 but we did once remove1 from the tower of ,st4 ,mary's ,church1 ,taunton1 a copper wire rope conductor of th of an inch in diameter ,a4 #jfj in41 said to be especially made to order--certainly the largest we ever came across2 but it failed to give the necessary protection in a lightning storm1 which did much damage to the tower and roof of the church4 ,as capacity or weight of copper is the most important for safe conduction1 copper wire rope is very deceptive in this respect1 as will be seen by the following comparisons1 viz43--,a copper wire rope conductor of inch diameter ,a4 #jaa in4 weighs #b ounces per foot1 not equal to a plain solid band inch wide and inch thick ,a4 #jjdf in41 which weighs #bijg ounces per foot4 ,a copper wire rope conductor of inch diameter ,a4 #jbj in4 weighs #e ounces per foot1 not equal to a solid band of inch wide and inch thick ,a4 #jjib in41 which weighs #ehad ounces per foot4 ,a copper wire rope conductor of inch ,a4 #jca in4 weighs #i ounces per foot1 not equal to a solid band of #a inch and inch thick ,a4 #jaec in41 which weighs #ifij ounces per foot4 ,this is the largest size of wire rope conductor made or used4 ,from the above will be seen what protection can be given by conductors of such small capacities2 and we may add that solid band conductors of the same weight1 and superior in every way1 can be fixed at less than half the cost of the wire rope1 foot for foot4 ,copper chains and copper wire bands1 as conductors1 answer in so uncertain a manner with the galvanometer1 that they should never be used4 ,iron in any form should be avoided1 from its lower conducting power1 and its utter uselessness when in a rusty and decayed state4 ,with regard to testing with the galvanometer1 the mere testing of the conductors is no proof of the security of the building itself4 ,we not only test the conductors1 but also the building1 to prove that it is under safe conduction in lightning storms4 ,in conclusion1 we beg to state that our patent system of protection is the application of one or more main down and ground copper conductors and sizes1 according to the height and area of the building1 the fitting of the copper bands to each chimney-stack1 and connecting the same1 and the connecting of all the metals on the roofs thereto and to the main conductor1 so that there shall be no circuit by which the lightning fluid would be likely to attack without having its exit to the main conductor4 ,for high working chimney-shafts we fit a copper band round the top1 and four points thereon connected to main down conductor4 ,for further information1 we earnestly solicit the careful perusal of our pamphlet and papers herewith4 ,j4 ,w4 ,,gray ,,son4 99 99 99 99 99 ,,chippendale ,,mews1 ,,harrow ,,road4 #a4 ,upper terminals pointed with one or more points1 according to the nature of the building to be protected4 ,dimensions vary in like manner4 ,material--copper or brass1 with electro-gilded points4 #b4 ,conductor composed of copper or galvanized rope1 according to height1 c41 of building1 c41 dimensions varying with resistance of the circuit4 #c4 ,the sectional area varies with the length4 #d4 ,joints made1 as far as possible metallically2 where solder cannot be used1 screw joints are made use of4 #e4 ,attachment to building direct by metallic ties of requisite form4 #f4 ,ground connection--,when practicable1 the end of conductor is metallically connected with gas or water main1 otherwise a hole is dug deep enough to meet always moist earth4 ,the end of conductor is either attached to an earth plate1 or coiled up in a bundle and surrounded by coke4 #g4 ,the area protected is supposed to be a radius equal to the height of conductor4 #h4 ,if more than one terminal is attached to one conductor1 the size of the latter is increased1 except under certain conditions4 ,f4 ,,russell ,,co4 99 99 99 99 99 #acg1 ,,princess ,,street1 ,,manchester4 #a4 ,a copper tube #a inch diameter or #a inch diameter1 finished at the upper end1 with a forged copper point or cone1 connected with the tube by a cast copper 7or gun-metal7 coupling1 into which coupling are also screwed three or more smaller points round the larger central one4 ,at the lower end the tube is screwed into a somewhat similar coupling1 to receive also the brazed and screwed end of the conductor4 ,or a solid copper rod inch diameter ,a4 #jbj in41 or wrought iron rod #a inch diameter ,a4 #jgi in4 7where iron conductors are used7 the rod in either case forged to a blunt point1 and screwed at the lower end1 like the tube first described1 to fit the coupling4 #b4 7a74 ,copper wire rope of #g strands each1 ,no4 #aj ,birmingham wire gauge1 or in specified cases of ,no4 #h or #g wire gauge1 making1 when spun1 a rope with a sectional area varying from #g_/af to #aa_/af4 7b74 ,solid copper rods inch diameter ,a4 #jbj in44 ,solid iron rods #a inch diameter ,a4 #jgi in44 7c74 ,copper band or 8tape0 of sizes from to #b or #c #c_/af inches ,a4 #jji to #jch or #jef in44 7d74 ,copper tube inch diameter outside1 and inch thick ,a4 #jbj in4 #c4 ,although no definite rule exists for the proportional sizes of the conductor1 it is usual and prudent in a large building to employ for the main conductors1 which should come from the highest and most exposed points to the earth in the most direct way1 a larger conductor than would be required for a small building1 and the branches or connections to this main conductor may be smaller in sectional area than the principal one4 ,thus1 a church tower with four angle pinnacles may be protected by four finials or points1 one to each pinnacle1 and these four parts fitted to rope of #g wires ,no4 #aj gauge ,a4 #jaj in41 to be united to a continuous band round the parapet1 from whence a rope of #g wires ,no4 #h gauge ,a4 #jae in4 should descend into the earth2 or an infirmary or workhouse built with wings would have1 perhaps1 three direct rod conductors1 one to each chimney stack1 and connections with the water spouts1 or lead flashing made of small copper tape ,a4 #jji in4 soldered to the lead and worked round the rods4 #d4 ,the fewer joints the safer1 and for this reason--the copper rope or tape is better than the rod or tube1 as the former is made conveniently any required length1 and the danger of a fault or break in the continuity is avoided4 ,of the necessary joints the rope requires one at its junction with the top rod or tube2 this is made by brazing a small ring of brass 7or copper7 round the rope2 the solid end thus formed being chased with a deep male thread1 which fits the prepared base of the rod4 ,the branch conductors or connections1 with adjacent constructive or decorative iron work--as beams1 girders2 cresting1 vanes1 c41 are made by threading a bead with a similar ring to receive the branch1 as that already described4 ,where the branch reaches its object a ring or solid coupling should be 8tapped0 into the girder or cresting1 to ensure thorough metallic connection1 if the destination of the branch be the lead flashing1 the seven wires must be opened like a fan1 and each wire strongly soldered with common plumbers' solder to the lead-- 7b74 ,copper or iron rods are made continuous by couplings of either metal1 as the case may be1 which should exceed the diameter of the rods by enough metal to allow of a good thread4 ,these couplings should be hexagonal or octagonal in plan1 to allow the workman a certain grip2 and the thread should be of the kind called right and left1 so that while screwing one length he may not unscrew the other4 ,these conductors require very careful1 steady workmen1 as a great element of danger exists in these numerous joints4 #e4 ,the various natures of the buildings provided with conductors require separate1 and often different treatment3 but the principle in all cases is the same1 viz41 to attach the conductor closely to the fabric1 and the more the conductor is made an integral part1 as it were1 the more efficacious it will be4 ,any attempts at so called isolation are opposed to the theory of protection by conductors4 ,the mechanical means of fixing are best illustrated by diagrams1 the chief objects to be considered are-- 7e74 ,permanence or strength and durability4 7f74 ,room for expansion of the conductor4 7g74 ,facility in fixing without cutting or breaking the conductor4 7h74 ,neatness in appearance4 ,these objects are gained by a careful consideration of the materials to which the conductors are fixed by 8holdfasts10 for stone1 slate or tiles1 wood1 and iron4 ,it is important that sharp bends be avoided4 ,a string course1 for instance1 should be drilled1 and the rod or rope passed straight through4 ,also1 that any metal bodies in the line of the conductor should be connected with it by staples screwed into such bodies4 ,it is most necessary that the ends of vane bolts or rods should be joined to the conductor1 or1 where this is impossible1 should be fitted with an independent wire or rod to the earth4 #f4 ,the connection with the ground is of special importance1 as the object of the conductor is to provide a free passage between the two currents1 and if this be not done1 a lateral discharge is pretty sure to result4 ,a building provided with suitable conductors1 properly fixed1 should at all conditions of the atmosphere1 allow a free course to the electricity1 and be in all its parts electrically equivalent1 and with this intention the several parts 7as mentioned in answer to question #c7 are brought into connection with each other or with the ground4 ,the actual length of the ground conductor is fixed by the nature of the subsoil1 as it is obvious that dry sandy soil is unsuitable for a termination4 ,we therefore continue the rope or tape until a good damp earth is reached1 if possible1 a spring or open water--generally speaking1 about #e to #aj yards will be sufficient in most localities4 ,the conductor is then buried #e to #aj feet1 or upwards1 in the damp earth or water4 ,if a rope1 the several strands are unravelled and opened out3 if a rod or tape1 a discharging fork is usually attached to the end to promote the easy discharge1 for which purpose it is also usual to fill the trench with charcoal4 ,the trench must be dug with a slight fall from the building downward4 #g4 ,the extent of area supposed to be protected by the conductor is estimated by many as included in a radius of double the height of the conductor from the base line2 but the immunity from accident enjoyed by many buildings situated at a greater distance from a number of tall factory chimneys2 or to take an opposite example1 in a city where there are many lofty spires or towers1 would go to show that a number of conductors attached to tail objects1 serve to obviate the dangers arising from lightning by providing1 at many different points1 a direct communication between the positive and negative currents which exist in the clouds and earth4 ,we have never known a church spire1 when the conductor was fixed in accordance with ordinary skill1 injured by lightning2 and the tall factory chimneys of our manufacturing towns afford strong corroborative evidence of the value of conductors1 and this in two ways--first1 because those to which conductors are fixed1 do not get struck2 and1 second1 because those unprovided with conductors1 do get destroyed from time to time4 #h4 ,a reference to the answer to ,no4 #c question1 will show that we consider that when several terminals are used1 an increased diameter is advisable in the main or principal conductor2 but it must be remembered that either of the conductors referred to in the answer to question #b1 is greatly in excess of what many eminent electricians consider necessary4 ,a single wire being thought sufficient of #c_/cb inch diameter 7,a4 #jjf in47 for any ordinary current of electricity4 ,but both the ,english and ,french ,governments have thought it prudent to specify a copper body1 with a sectional area of inch in ,english1 or #a centimetre in ,french 7#jdj in47--partly to provide against corrosion1 which would rapidly deteriorate a thin wire1 and partly to obviate the danger of the melting of the smaller conductor under the continued force of an unusually strong shock of lightning4 ,we1 therefore1 respectfully follow the decision of such experts as have1 by careful experiment and considerable diligence1 acquired the knowledge they possess--both as to the substance1 the form1 and the treatment of this subject2 and have only to add the fact1 that any small experience we have practically had1 goes to support the conclusions already arrived at by these authorities4 ,,freeman ,,collier4 99 99 99 99 99 #bd #bf1 ,,lever ,,street1 ,,manchester4 #a4 ,our upper terminals are made of copper or brass1 plain spike or ball with spike at top1 and three radiating from it1 or four or five spikes radiating from the ball4 ,attached to the ball 7screwed into it7 is a solid rod of copper1 to which the conductor is fastened1 as explained below4 #b4 ,conductor is made of good quality copper wire strand #g ply3 inch ,a4 #jaa in4 to #g_/af inch ,a4 #jae in4 diameter4 #d4 ,joints of the strand not usually permitted1 as we spin it any reasonable length4 ,the end of the conductor is knotted and drawn through a cup-shaped ring of metal one end1 the top of which is screwed into the bottom of the solid rod of the terminal4 ,this makes a good connection4 #e4 ,copper holdfasts fasten the rod to the building4 #f4 ,ground end is coiled loosely in damp earth or a well4 ,,richard ,,johnson1 ,,clapham1 ,,morris4 99 99 99 99 99 #ahj1 ,,rottemore1 ,,glasgow4 ,we beg to reply to your queries on the material1 system1 and fitting of lightning conductors1 as practiced by us for over #be years1 during which time we have never had a building injured in which we have been engaged1 and have fitted from #ae1jjj to #bj1jjj feet a year1 without advertisement4 #a4 ,uniformly solid copper1 consisting of #a centre concave point1 about #ad inches long1 presenting #h sharp angles #c inch surface2 this is surrounded by #d smaller points of same construction4 ,these all terminate or spring out of a hollow copper ball1 which is screwed on a copper tube inch diameter inside1 and from #d inches to #e inches long1 according to requirement4 ,the copper cable is passed through this tube1 is knotted inside of the ball1 and the points are all screwed against it1 which forms the point of contact1 and thoroughly fixes the cable at the top2 but the fixing of the top or terminal rod is fashioned in accordance with the requirements of the building or material to be fixed to4 #b4 ,uniformly copper cable constructed of #di strands1 hard drawn square copper wire ,nos4 #ag1 #ah1 or #ai w4g4 #c4 ,we never use less than #f-;inch surface1 i4e41 measuring the circumference of each wire1 we contending that surface is the only power of the conductor4 ,up to #aej ft4 we use ,no4 #ai 7 inch diam47 ,a4 #jbj in41 inch for a longer length of cable 7i4e41 #ag or #ah7 ,a4 #jdd in44 #d4 ,usually with a gun-metal screwed coupler4 #e4 ,with brass holdfasts1 lined with porcelain1 glass1 or guttapercha4 #f4 ,spread out end of strands of cable like a fan1 and bury it in the moist earth a few feet deep1 in an oblique way tending from building4 #g4 #cj to #dj yards4 #h4 ,we invariably run one cable from each terminal or top rod3 but in spires we commonly take a connection from the bottom of the vane rod1 and connect it to the main conductor1 which goes to the highest point of vane or final3 if the former1 we fix a copper bush or disc to the vane rod at foot of vane1 which is fast to cable1 and a corresponding one on vane1 with cable at highest point1 when the cable is fringed out1 presenting its #di points1 and by these discs the vane revolves with that portion of the conductor attached1 and the point of contact is given by the discs4 ,c4 ,h4 ,,pennycook ,,co4 99 99 99 99 99 ,,all ,,saints' ,,works1 ,,derby4 #a4 ,form for upper terminals3--,a straight copper tube1 inch diameter2 thickness of metal1 #ae ,b4,w4,g4 ,a4 #jae in41 with solid copper point 7no branches72 the point is soldered and rivetted into the tube2 or a solid copper rod1 inch diameter ,a4 #jbj in41 tapering towards the top4 #b4 ,material and dimensions of conductor3--,either a copper band of #b inches wide and ,no4 #af ,b4,w4,g4 thickness ,a4 #jaf in42 or a copper wire rope1 inch diameter1 of #f strands1 each strand containing #f wires ,a4 #jbj in44 #c4 ,proportion between length and sectional area of conductor3--,the inch copper rope ,a4 #jbj in41 or #b #af ,b4,w4,g4 band ,a4 #jaf in41 is used for heights not over #abj feet2 for higher buildings1 a inch rope ,a4 #jdd in4 or band1 #b #ab ,b4,w4,g4 ,a4 #jbg in4 should be used4 #d4 ,joint1 how made3--,joint is made between band and copper rod with a brass screwed socket1 the rod is soldered and rivetted into socket1 and the band is soldered round socket1 then soldered and rivetted4 ,when the copper rope is used1 a hole is drilled into socket1 same diameter as rope1 at the lower end1 and turned out conical shape2 the rope is then passed through the socket1 the ends spread out1 and the spaces filled up with solder4 #e4 ,attachment to building3--,the conductor is fixed close to building without insulators1 and is brought into close contact with the spouting2 is closely attached to chimney and walls by means of copper straps and copper nails driven into the masonry4 #f4 ,ground connection3--,should a good1 permanent drain be near1 the conductor is brought to it and bound round and firmly fixed4 ,if there should be an open drain or brook1 the conductor is brought under it at sufficient depth that if the stream be dry at any time there will be sufficient moisture to carry away the charge without disruption4 ,should there be neither drain pipes nor brook sufficiently near1 the conductor is taken from #ab to #bj feet below the surface to the clay1 where it is certain to be always damp1 even in seasons of the greatest drought ever known4 ,in no case should the earth connection be taken into a closed tank or well4 ,if a band be used1 it should be cut into strips about #ah inches long and laid in different directions2 rope should be unwrapped and spread in a similar manner4 #g4 ,supposed area protected3--,it is impossible to determine exactly the area the conductor protects4 ,it is erroneously supposed that the rod will protect buildings within its radius1 but experience will not bear out this axiom4 ,many instances may be related of buildings being struck much within the radius of well-protected churches or chimneys4 ,the protection a conductor affords depends to a great extent on the relative positions of the electric discharge and the objects that it may meet in its course4 ,as a general rule1 a church with a high spire with a proper conductor may be considered to protect the remainder of the edifice2 but a low1 straggling building should have several conductors at the outside highest points4 #h4 ,if there is more than one terminal is the size of conductor increased8--,no2 as sufficient material should always be used to carry off without disruption the heaviest known charge1 it is unnecessary to increase the size of conductor4 ,should two or more upper terminals be connected with the main conductor1 the size of material need not be increased2 for if two or more terminals receive the charge simultaneously it necessarily follows that it is sub-divided2 therefore the conductor will have no more work than if one point only had been struck4 ,note4--,we quite agree with ,snow ,harris regarding insulators1 that if there be anything in insulators they are a disadvantage1 for if the building be struck in any other part than the conductor1 the current cannot easily find its way to the conductor4 ,the current will take the line of least resistance2 therefore it is reasonable to assume that the building is more certain to escape the disruptive force of lighting when the conductor is in close proximity with the building4 ,,john ,,davis ,,son4 99 99 99 99 99 ,,bigg ,,market1 ,,newcastle-,,on-,,tyne4 #a4 ,for upper terminals ,i generally use inch diameter solid copper rod ,a4 #jbj in41 or inch diameter tube ,a4 #jbd with four points1 and ,i fix them #d or #f feet above the building they are intended to protect4 ,i always endeavour to get the upper terminal as near the size of the conductor as is consistent with strength4 ,i make my points of the best copper tipped with platinum4 #b4 ,for the conductor ,i use inch diameter copper wire rope ,a4 #jbj in41 which is 7in my opinion7 the best and most applicable conductor used1 as it appears to be an open question1 at present1 whether it is surface or mass which conducts4 ,if it is mass1 then a tube conductor is insufficient4 ,if it is surface1 then a solid rod is superfluous4 ,the copper tape conductor ,i consider the worst form of any1 as it bends too easily round sharp corners1 projections1 c41 of buildings1 which is a thing to be avoided as much as possible4 ,a conductor should be brought to earth as direct as possible1 and with no bends if they can be avoided4 ,the copper wire rope conductor has both surface and mass conduction1 and can be led about roofs and other difficult places better than any other form of conductor that ,i know of4 #c4 ,none2 ,i imagine it is not necessary4 #d4 ,i avoid joints as much as possible2 but1 when they must be made1 ,i scrape the ends of my wire bright1 and then splice or interlace them together1 covering the whole with thin sheet lead--,i object to solder1 as ,i think it must interfere with surface conduction2 the wire is fastened to the upper terminal1 with a ,matthew ,walker knot let into a hollow cup1 and the terminal screwed down on it4 #e4 ,i attach my wire to the building with a brass or gun-metal holdfast #d inches long1 having a hole1 the inner edge being flush with the wall of the building1 so as to allow the conductor to touch the wall of the building all the way up1 and still allow plenty of room for the free passage of the electric fluid4 ,i do not approve of insulators1 nor yet of that kind of holdfast that is driven in tight on to the wire1 for ,i think that must interfere with the clear passage of the electric fluid4 #f4 ,i cut a trench some #ae or #bj feet long1 gradually deepening from #a foot at the commencement to #d ft4 at the termination1 which ,i fill with pounded charcoal and bury the wire in it4 ,earth-plates are not necessary when this is done4 #g4 ,it is calculated that a conductor will protect a surface in the shape of a cone1 the diameter of the base of which is equal to the height of the conductor4 ,thus1 if a conductor were #ajj feet high1 the space protected would be represented by a straight line drawn from a radius of #ej feet from the base of conductor1 to a radius of #h or #aj feet from its highest point4 #h4 ,i consider1 if there are two terminals1 there should also be two wires1 or the wire should be of sufficient capacity to carry off a double charge1 in case both terminals should be struck at one time4 ,i think the conductors should certainly be of sufficient capacity to carry off any charge that might be received by the terminals1 be they few or many4 ,t4 ,,massingham4 ,,appendix ,b4 ,,analysis ,,of1 ,,and ,,remarks ,,upon1 ,,the ,,views ,,of ,,manufacturers4 ,on ,nov4 #adth1 #ahgh1 a circular was issued to the principal lightning-rod manufacturers in this country1 inviting their replies to various questions that were submitted to them1 and also any remarks that they might wish to lay before the ,conference4 ,replies have been received from-- ,messrs4 ,,wilkins ,,weatherby1 of ,london4 ,messrs4 ,,gray ,,son1 of ,london4 ,messrs4 ,f4 ,,russell ,,co41 of ,london4 ,messrs4 ,,johnson1 ,,clapham1 ,,morris1 of ,manchester4 ,messrs4 ,,freeman ,,collier1 of ,manchester4 ,messrs4 ,,pennycook ,,co41 of ,glasgow4 ,messrs4 ,,davis ,,son1 of ,derby4 ,messrs4 ,,massingham1 of ,newcastle-on-,tyne4 ,all well-known firms1 who have written fully and freely1 and whose experience is very extensive4 ,it is impossible to read these replies without feeling the absolute need of such a ,conference as that which has been formed1 to collect facts1 to digest opinions1 and to endeavour to formulate some guiding principles for uniformity in practice--for here we have the most diverse modes of execution detailed1 the most opposite views expressed1 and the most varied experience narrated4 ,in fact1 some ideas enunciated are quite opposed to the teachings of science4 ,where practice is so opposite1 error must abound3 and1 therefore1 there must be great need for an effort to reduce the system of constructing lightning conductors in this country to some uniform basis4 ,on no one single point1 except in the use of copper and the necessity for reaching damp earth1 do any two manufacturers agree in adopting similar measures4 ,i will take each question submitted seriatim4 #a4 ,form1 dimensions1 and material usually adopted for upper terminals4 ,there are single points and branching points1 fine points and blunt points1 cones1 spikes1 balls with spikes on top1 and balls with radiating spikes4 ,the dimensions vary with each form1 and they are made of solid copper and copper tube1 of brass1 of iron1 and of gun-metal4 ,the ends are sometimes silvered1 sometimes gilt1 and sometimes tipped with platinum4 ,but there is no rule or uniformity2 and one manufacturer acknowledges that1 while he sometimes tips the points with platinum1 he considers the practice to be altogether superfluous4 ,now it is clear that if there be any electrical efficacy in points as points1 they should be made in such a form1 and of such a material1 as to maintain their efficiency permanently4 ,the writer is very strongly of opinion that the efficiency of lightning conductors is due principally to the peculiar electrical action of their points4 ,he sees no advantage whatever in multiplying these points4 ,in his opinion each conductor should end in one fine platinum point4 ,it would thus act as a dissipator of the electric charge in its immediate neighbourhood1 and would then prevent1 and not favour discharge4 ,moreover1 points demand frequent inspection1 attention1 and renewal4 ,he thinks that one function of the ,conference should be to examine some of these points in situ1 if possible4 ,at present they are erected and left to their fate4 #b4 ,the ,material and ,dimensions of the ,conductor4 ,the use of copper is almost universal1 but two manufacturers occasionally use iron4 ,the form varies4 ,the majority use wire rope1 but some use rods1 others bands or tapes1 others tubes4 ,one firm uses a cable 8constructed of #di strands of hard-drawn square copper wire40 ,another firm uses a wire rope1 simply because 8it appears to be an open question1 at present1 whether it is surface or mass which conducts40 ,the dimensions are as varied as the form1 from a wire rope th of an inch in diameter to a copper band #c inches wide and th thick4 ,the only point worthy of note is1 that no one uses a smaller conductor than a copper rope th in diameter 7i4e4 #d oz4 of copper per foot run74 ,leaving the dimensions as a question for future investigation1 the points submitted for the consideration of the ,conference under this head are-- #a4 ,is conduction a question of surface or of mass8 #b4 ,is copper alone to be used8 #c4 ,is the conductor to be in the form of a rope1 a rod1 a tube1 or a band8 ,now1 on the first point the writer entertains no doubt whatever that the conduction of atmospheric electricity is simply a question of mass1 and that the lightning protector acts simply as a conductor obeying the laws of ,ohm4 ,on the second point he sees no objection whatever to the use of iron1 when properly galvanized1 in situations free from chemical impurities4 ,the reasons urged against its adoption are extremely weak4 ,first1 it is said to decay rapidly2 and1 secondly1 it is said to be a very much worse conductor than copper4 ,the rusting of iron is almost entirely checked1 in pure air1 by galvanising or coating with zinc4 ,it is used for nearly every other purpose in connection with building1 and it is difficult to understand why it should be discarded on account of its liability to decay for this particular purpose1 where it is always under supervision4 ,again1 pure copper conducts about six times better than pure iron3 but we never get pure copper in lightning conductors4 ,moreover1 the manufacture of iron wire for telegraphic purposes has increased so enormously during the last two or three years1 that the wire now supplied conducts #ej per cent4 better than it used to4 ,hence the difference between the two in this respect is not so great as theory indicates2 and it would be well for the ,conference to satisfy itself on this point by having similar sized wires made of the two materials1 and having them measured electrically for their resistance4 ,but it has been pointed out by the late ,mr4 ,brough 7,phil4 ,mag41 ,may1 #ahgi71 that by regarding 7#a7 the influence of the rise of temperature1 7#b7 the difference between the specific heats1 and 7#c7 the relative dimensions1 iron conductors can be made much smaller than was formerly supposed3 and1 that as iron is so much cheaper1 iron rods can be made equally efficient for a much less sum than copper4 ,moreover1 the use of iron enables the architect to use one kind of metal throughout his structure1 and thus avoid anywhere the contact of dissimilar metals1 which always results in decay4 ,on the third point1 the writer is clearly of opinion that a galvanized iron rope is amply sufficient for country residences and buildings free from chemical actions4 ,in such places1 and in towns1 copper should be used4 ,a rope1 whether of iron or copper1 is easily handled1 it can be made of any size1 it can be led in any direction without bends or angles1 it is neat and easily jointed1 diverted1 or lengthened4 ,the writer refrains from expressing any opinion on its dimensions here1 for this is a point that will require most careful examination by the ,conference4 #c4 ,is there any definite proportion between the length and sectional area of the conductor8 ,the majority of the manufacturers increase the size of the conductors for high buildings--one making the limit #abj feet1 another #aej feet1 while a third 8varies the sectional area with the length40 ,one firm does not consider any difference necessary1 while another takes it that the sectional area should be the same irrespective of length1 for 8lightning does not vary in intensity while passing through a conductor of greater or less length40 ,now1 the laws of electricity clearly show that to maintain equal efficiency we must vary the sectional area as we increase the length of the conductor2 but it is a question for the ,conference to decide whether we should not recommend a rope of uniform dimensions that would be equally applicable for high and low buildings4 ,within ordinary limits the necessity for increased thickness for increased height is scarcely evident1 but the remedy of an increased sectional area1 with the number of separate points erected1 is very clear4 ,indeed1 each point should be the terminal of a conductor1 whose sectional area should be uniform to the earth4 ,for if it be not so1 and each conductor be fully charged with electricity1 then when the sectional area diminishes there will be congestion1 resulting in heat and discharge to the building4 ,hence the thickness of the main conductor must increase with the number of separate points erected4 #d4 ,joints1 how made4 ,some are rivetted1 others are screwed1 others are coupled by right and left-handed screws4 ,tubes are socketed into each other4 ,in one case 8the end of the conductor is knotted and drawn through a cup-shaped ring of metal40 ,there can be no doubt that joints are the greatest source of danger in lightning conductors4 ,if a joint be imperfect1 and the conductor be conveying a charge to earth1 heat will be generated there1 the conductor may be fused and rendered useless1 and the discharge will be diverted to the building4 ,or the joint may be so bad--that is1 its resistance may be so great--that it renders the conductor practically useless1 for other parts of the building will offer easier paths to the earth4 ,though the use of solder is pretty general1 it is not universal4 ,indeed1 one manufacturer objects to it because 8it must interfere with surface conduction60 ,it certainly should be imperatively used4 ,no joint can possibly be perfect that is not metallically continuous4 ,careful soldering is the only certain mode of securing this1 and that this is practicable is evident from the millions of perfect joints in telegraph wires4 ,to scrape the ends of wire bright1 and cover the whole with thin sheet lead1 as is done by one firm1 is simply to court danger4 ,the absence of joints in wire rope is one great element in its favour4 #e4 ,attachment to building1 how made4 ,some attach the conductor to the building by copper straps and nails2 some use holdfasts1 either of copper wire or gun metal2 others use staples2 one uses metallic ties4 ,several pass the conductor through insulators of glass1 porcelain1 or earthenware4 ,but the majority discard insulators as useless4 ,in the opinion of the writer they are quite right1 for it is difficult to understand what useful function the insulator performs4 ,one fact that occurred in #ahcg is given as a reason for their use1 but the fact militates against the efficiency of the conductor rather than the absence of insulators4 ,if the conductor were perfect there could have been no concussion at the point of attachment4 ,if it were imperfect there may have been1 for the discharge would seek other paths to earth4 ,some manufacturers use holdfasts of a different metal to that of the conductor4 ,this is wrong1 for where different metals are used galvanic action sets in1 tending to decay and rupture4 ,the attachments for this reason should always be of the same metal as the conductor4 #f4 ,ground connection1 how formed1 and of what extent4 ,the necessity for reaching moist ground is generally recognised1 but various curious ways for making earth connection are suggested4 ,one firm considers that a band cut into strips #ah inches long would suffice1 while another says that not less than #cj feet1 in two or three branches1 with fork at the end of each band1 should be used4 ,one firm is very brief3 8,ground end is coiled loosely in damp earth or a well40 ,the use of coke1 powdered charcoal1 or carbonaceous materials1 is insisted upon by others4 ,it is questionable whether the difficulty of fitting a good connection with the earth is fully realized4 ,none but telegraphists know the great difficulty there is in doing this4 ,the first object to be secured is a good damp soil1 and the next as large a conducting surface as possible4 ,metal pumps1 iron1 gas1 or water pipes1 wells in which plates of metal #b or #c feet square are placed1 or similar plates may be buried in perpetually damp ground1 or in holes well filled with powdered coke4 ,moisture in some form is essential1 and without it a lightning protector is of small service4 #g4 ,extent of area supposed to be protected4 ,the majority of the firms consider that the area protected has a radius equal to the height of the conductor2 but one firm considers that this should be multiplied by five or six times2 while another asserts1 8that no appreciable extent is protected by a single rod conductor20 and another1 that 8many instances may be related of buildings being struck much within the radius of well protected churches or chimneys40 ,we have no experience at present to enable us to form a definite opinion on this point4 ,the ,committee of the ,french ,academy1 gave the radius as equal to twice the height of the conductor from the ground1 but buildings have undoubtedly been injured within this limit4 ,the writer does not think that a greater radius than the height should be taken3 but thinks that this is one of the most important questions that the ,conference could determine4 ,calculation might1 to a certain extent1 settle the point3 but it is more a case for experience4 #h4 ,if there is more than one terminal1 is the size of the conductor increased8 ,this question has been partially considered4 7,see ,no4 #c47 99 99 99 99 99 ,some firms do not consider any increase necessary3 others think that when two or more terminals are used1 the main rope should be somewhat enlarged2 while others run one cable from each terminal1 or make the conductor of sufficient capacity to carry off the double charge4 ,the writer considers that every conductor should be complete in itself3 or1 if this is inconvenient1 then the size of the main conductor should be enlarged in proportion4 ,it does not at all follow1 as one firm implies1 that if two or more terminals receive the charge simultaneously1 it is necessarily sub-divided4 ,each charge may be full and complete in itself1 and be sufficient to fill the wire2 and1 therefore1 if the main conductor be not increased1 accident may result4 99 99 99 99 99 ,there is no doubt whatever that great consideration should always be given to the lessons of experience1 and the opinions of those who have made the erection of lightning conductors for #ce years their especial practical study1 are much entitled to weight2 but such practice may have originally been based on error1 and the teachings may not have been guided by science4 ,where such variety of practice abounds1 there must be fallacy somewhere1 and1 therefore1 danger2 and not the least of the beneficial labours of the ,conference will be to point out to these different practical men1 where their faults and their departures from truth exist4 ,w4 ,h4 ,,preece4 ,august #hth1 #ahgi4 ,,appendix ,c4 ,,reply ,,from ,,manufacturers1 ,,received ,,after ,,the ,,completion ,,of ,,the ,,analysis ,,which ,,forms ,,appendix ,b4 ,,faraday ,,steam ,,works1 ,,st4 ,,john',s ,,road1 ,,huddersfield4 #aath ,november1 #ahgi4 ,,sir1 ,enclosed we have pleasure in handing you our replies to the eight questions which you ask lightning rod manufacturers and erectors1 together with three tracings1 showing our system of protection under different conditions4 ,in the case of ,nottingham ,castle we considered it necessary1 on account of the rock on which the castle was built1 to adopt an extensive system of lateral points in earth termination1 by running all the main conductors from the building down the shrubbery into the moat1 where we formed the flat copper band into the form of gridirons1 in which several hundred feet of the copper band has been used1 and the termini of the ribs pointed1 and the whole being sunk eight feet1 and two cart-loads of gas carbon laid over each grid4 ,yours obediently1 ,,sanderson ,,co4 ,,replies ,,to ,,the ,,questions ,,of ,,the ,,lightning-,,rod ,,conference4 ,i4--,usually a length of copper tube #e feet long #a inch diameter ,no4 #h ,b4,w4,g41 which is termed the elevation rod1 surmounted by a solid copper point1 forged from th of an inch round bar1 wrought three parts of its length to a square tapering point1 the said elevation rod and point are screwed together by a copper ball-shaped union1 into which are screwed four smaller points at an angle of #de degrees4 ,when fixing lightning conductors on church spires and turrets we usually run the copper tape a few inches above the vane or finial1 having previously prepared and pointed the tape2 by this system all joints are avoided4 ,,ii4--,we1 the sole inventors1 manufacture the solid copper tape lightning conductors of the following sizes3-- ,nos4 #a #b #c #d #e #ba #bb #bc in4 in4 in4 in4 in4 in4 in4 in4 #a_/ab #a #a #b #aa_/af #aa_/afba_/af ,a #je #ji #ac #ai #be #jf #ji #ac and in continuous lengths up to #ejj and #fjj feet4 ,,iii4--,yes4 ,for heights of say #ej feet we recommend our ,no4 #b 7 in4 in47 size2 for #ajj feet our ,no4 #c 7#a in4 in47 size2 and for #bjj feet or over1 our ,no4 #d 7#a in4 in47 size2 or our ,nos4 #ba 7#a in4 #a_/af in471 #bb 7#a in4 #a_/af in471 or #bc 7#b in4 #a_/af in47 according to position and circumstances4 ,,iv4--,in the case of church spire or turret conductors we have no joints whatever1 as described in ,answer ,i41 but where elevation rods and points are used we make a copper coupling1 screwed at one end to receive the elevation rod1 and at the other end to receive the copper tape1 which is firmly rivetted into the coupling1 and thence soldered or brazed4 ,but when a complete system is employed with branches or tributaries1 running from several points on to the main conductors1 we make the joint by means of copper rivets1 and then solder4 ,v4--,by means of gun metal clips1 or holdfasts1 let into the building1 which secures the copper tape in close contact with the face of the building4 ,under no circumstances do we use glass1 ebonite1 or other insulators4 ,,vi4--,in good moist earth #e feet or #f feet deep we simply run the copper tape out from the building some #bj feet1 and then rivet a copper earth plate on to same1 or sometimes employ a large gridiron made of copper tape1 using as much as #bjj lineal feet in its construction4 ,wherever we make earth terminations in rocky1 dry1 or gravelly soil1 we always fill in with a load of small coke1 charcoal1 or other carbonaceous matter1 and also divert the rain fall-pipe system over the termination so formed2 also1 wherever possible1 we connect the conductor with the gas and water systems outside the building4 ,in all cases of earth terminations1 the size of earth-plate is in proportion to the size of conductor employed1 and other circumstances4 ,,vii4--,we are unable to come to any conclusion as to any definite area which one lightning conductor will effectively protect1 and no two writers appear to agree on the subject2 but from actual practical experience of #cj years1 combined with the closest observance and research1 we are in the position to say1 emphatically1 that a conductor on one prominent elevation--for example1 a turret will not protect a similar elevation1 be it only #a yard1 or #ej yards distant2 but that providing that two prominent features be provided with a conductor point on each1 then on the same foundation1 we say that both of them would be effectively protected4 ,but for the purpose of simplifying and practically illustrating our views on this subject1 we enclose you tracings and particulars of several buildings for which we have designed the system of lightning conductors1 and which we believe to be perfect4 ,,viii4--,yes1--always1 and in proportion to the number of extra terminals adopted4 ,,sanderson ,,co4 ,,details ,,of ,,lightning ,,conductors ,,applied ,,to ,,nottingham ,,castle4 ,the following three engravings render very few verbal details necessary4 ,fig4 #a gives the east elevation of the castle1 it shows part of a flag-staff #aae feet high1 which has a conductor1 also three of the principal terminals1 and twenty-six minor points upon the building1 and by two dotted lines the position of two of the main conductors to earth4 ,the principal terminals are tapered iron tubes1 #ac feet long1 carrying copper tapes #a inch #a_/afth and terminating with copper points tipped with platinum2 the minor points are of solid copper #i inches long4 ,the main conductors to earth are copper tapes #b in4 #a_/afth4 ,illustration3 ,,fig4 #a4 ,fig4 #b give a plan of the roof1 much of which is of glass with wooden rafters4 ,the twelve principal terminals are shown by small rings1 the ninety-four minor points by round dots1 the horizontal copper tape 7#b inches #a_/afth71 uniting all the upper terminals1 by a pecked line1 and the position of the main conductors to earth by dotted crosses4 ,all the gutters are metallically connected with the conductors4 ,illustration3 ,,fig4 #b4 ,fig4 #c gives a general plan 7for which we are indebted to the architects1 ,messrs4 ,t4 ,c4 ,hine ,sons7 of the castle and grounds1 and also a little section indicative of the precipitous eminence on which the castle stands4 ,from these it will be seen that two of the main conductors to earth are carried underground at a depth of about #d feet1 under the terrace and down the slope and terminate in trellis-work1 about #ad feet square1 of #b inches #a_/afth copper tape rivetted at every intersection4 ,the other earth contact is obtained by bolting the terminal on to the town water-main4 ,the total length of tape used in the earth connections was about #ejj feet4 ,,sanderson ,,co4 ,illustration3 ,,fig4 #c4 ,,appendix ,d4 ,,report ,,of ,,the ,,representatives ,,of ,,the ,,royal ,,institute ,,of ,,british ,,architects ,,to ,,the ,,lightning ,,rod ,,conference4 ,the ,council of the ,royal ,institute of ,british ,architects sent out upwards of #fjj circulars 7a copy of which follows this ,report7 to their ,architectural ,members requesting information as to injury by lightning to any buildings known to them4 ,the ,council also requested the same information from their ,honorary ,associates 7upwards of #ajj in number71 who are chiefly men eminent in the ,scientific1 ,literary1 and ,artistic world4 ,the ,council have received up to this date only #ce answers from ,architects1 and #a from the ,honorary ,associates4 ,of these answers many are to the effect that no case of injury has arisen to works under their direction4 ,the remainder give #cc instances of damage1 and enter1 in many cases1 very fully into the details of them4 ,the instances given may be roughly classified thus3-- ,there are #bf of buildings injured where there were no conductors4 ,in #i of these the lightning did some injury to the chimneys and other exposed parts1 and was then conducted safely to the ground through the metal gutters and rain water pipes4 ,in three other instances the lightning appears1 from the statement of persons in the building struck1 to have dispersed and passed out by open doors1 c4 ,we give no opinion as to this1 but the facts are distinctly stated4 ,in several other cases the lightning passed off in several distinct directions and currents4 ,there are #f cases of buildings being injured although protected by lightning conductors4 ,in one of them 7,no4 #ad7 the failure is clearly explained by the fact that the lower part of the conductor had been stolen1 leaving only two or three feet of it in the ground4 ,the lightning in this case broke through a wall #d feet #f inches thick1 at a height of #f feet from the floor to a gas pipe4 ,in another case 7,no4 #c7 a gable was struck1 although close to a spire and turret which had a lightning conductor4 ,in another 7,no4 #g7 the part struck 7a chimney7 was #fd feet away from a tower1 in the same building having a lightning conductor4 ,in ,no4 #bd the conductor was sufficient protection until it passed at a sharp bend round some mouldings2 these it injured1 but did no further damage4 ,in two cases 7,nos4 #ba and #bc7 the discharge injured some gas tubing near it1 and set fire to the gas1 and by its means to the building4 ,we beg finally to call attention to the drawings attached to ,no4 #g 7,mr4 ,colson1 of ,winchester71 showing the injury to trees #acj feet away in a direct line from a spire which was destroyed1 it having no conductor4 ,t4 ,,hayter ,,lewis1 ,v4,p4 ,,john ,,whichcord1 ,v4,p4 ,,circular4 ,,lightning ,,rod ,,conference4 ,,sir1 ,i beg leave to inform you that the ,council have appointed two of their members to meet delegates from several scientific societies in order to confer as to the best methods of protecting buildings from lightning2 and in accordance with a resolution of that conference ,i have the honour to forward to you1 by the desire of the ,council1 the questions appended below4 ,i shall be much obliged if you will return me this paper1 with any answer you may be in a position to make to the questions1 on or before ,monday the #bjth of ,january1 #ahgi2 and ,i remain1 ,sir1 ,your faithful servant1 ,,william ,h4 ,,white1 ,secretary4 #i1 ,,conduit ,,street1 ,,hanover ,,street1 ,w4 #aith ,december1 #ahgh4 ,,questions4 #a4 ,have any buildings1 in the construction of which you have been professionally engaged1 or which are otherwise well known to you1 been struck by lightning8 #b4 ,if so1 state briefly the damage done to them1 describing their general plan and construction by sketches or otherwise1 particularly noting the position of any metal work to roofs1 pipes1 c4 #c4 ,were the buildings furnished with lightning conductors8 ,if so1 describe them in relation to the following heads3-- 7a74 ,their materials and dimensions4 7b74 ,their attachment to building4 7c74 ,their connection with the ground4 7d74 ,their upper terminals4 7e74 ,the height of conductor above chimney or other adjacent part of the building4 7f74 ,if there existed more than one conductor state the distance from one another4 #d4 ,what was the distance of the point struck1 horizontally and vertically from the conductor8 #e4 ,was any damage done1 and if so how much1 to the conductor1 and in what manner8 #f4 ,give particulars as to any trees within a short distance of the building struck4 99 99 99 99 99 ,the replies received to this ,circular are too long to be printed in full1 they have therefore had to be epitomised in the following list1 and consequently cannot be given as separate answers to each question4 ,the replies were all numbered consecutively1 so that the numbers omitted in the list refer to circulars returned by members who had no information to give on the subject4 ,,replies ,,to ,,circular4 #b4 ,st4 ,aubyn1 ,j4 ,p4 ,week ,st4 ,mary1 ,north ,cornwall4--,the tower of this church stands on very elevated ground1 and has lofty pinnacles1 three of which have been struck at different times1 on each occasion one of these pinnacles was shattered1 and had to be taken down and rebuilt4 ,some of the stones are held by iron cramps1 but no iron or other metal spindles4 ,the roof of the tower1 as well as that of the church1 is slate1 without spouts1 and there are no lightning conductors to the building4 ,there is open country all round the church1 and no tree of any size within a mile of the tower4 ,the following detailed report was received direct from the ,rev4 ,g4 ,h4 ,hopkins1 the rector of the parish3-- ,an ,account of the position of the ,church of ,week ,st4 ,mary1 in the ,county of ,cornwall1 and the effect of ,lightning upon the ,pinnacle and ,tower when struck for the fourth time this century on ,november #hth1 #ahgh4 ,situation of the building4--,the situation of the church is at the northern angle of an extensive triangular plateau1 which towards the south is much broken by small valleys and low hills1 while the high land is for the most part moor1 broken in places by cultivated ground and small plantations4 ,within a quarter of a mile from the church1 on three sides1 the ground commences to fall very rapidly to a depth of #bjj or #bej feet2 it is three miles from1 and nearly #ejj feet above1 the sea2 to the ,n4,w4 lies ,widemouth ,bay1 one of the very few breaks in the cliff along the coast of ,north ,cornwall2 the entire extent of this break is quite a mile-and-a-half2 between the ,bay and the extremity of the plateau1 at which the church is built1 the surface is broken by low hills1 only one of which exceeds #bej feet above the sea level1 and this exception is separated by one valley from the church hill2 half a mile south of the church is the highest ground in the parish1 but neither this nor any hill for several miles exceeds in height the pinnacles of the tower4 ,the elevation of the building above the surrounding country can be better understood from a local rumour that #bh churches are visible from the battlements of the tower1 and the average size of a parish attached to each church is #fjjj acres4 ,the highest point of the pinnacle is #ij feet above the ground4 ,no mines or spring of water beneath it4--,there is no evidence of the existence of any metalliferous lode in the parish1 and certainly no such attractor of electricity lies beneath the church1 nor is there any spring of water near the foundations2 but as the surface soil is clay1 the rain water has no means of flowing away1 except over the surface1 and a few hours of moist weather make the soil like a wet sponge4 ,circumstances4--,the tower was struck at #f4de a4m4 on ,november #hth1 #ahgh1 the weather having previously been gusty1 with sudden storms of hail and rain as each heavy cloud came up from the sea3 many times during the night the downfall of hail was very violent1 and it was during one of these storms that the single electrical discharge took place2 the hailstones were considerable1 both in number and size1 when the flash occurred1 and they certainly commenced falling before the shock took place4 ,brightness of the flash4--,the brightness of the lightning was intense1 and ,i have been at some trouble to inquire into the effect which it had upon those who saw it4 ,i was awake1 and the lightning illuminated the room through double chintz curtains and dark-green blinds1 the windows looking away from the church1 and being more than a quarter of a mile from it2 during the storm a farmer took refuge in a closed cattle shed1 #bjj yards from the church1 and he spoke afterwards of his impression that he was surrounded by fire2 two farmers going to ,camelford fair1 were at the time waiting on the road1 a mile-and-a-half from the church1 and their impression was that they were enveloped in flame1 and the flame came between them2 these experiences were given to me at different times1 and were independent evidences of individual opinion4 ,at ,holsworthy1 eight miles away1 in a direct line1 two ladies were attending their sick mother1 and the vividness of the lightning obscured the brightness of the light of two candles and a paraffin lamp4 ,the loudness of the thunder4--,the loudness of the clap of thunder was very great2 of course it shook my house2 and a neighbouring rector1 who lives three miles away1 in an adjoining parish1 felt the effect of the clap to an extent which was very unusual2 at ,camelford1 lying ,w4,s4,w41 and distant about twelve miles1 with a considerable range of hills between1 the thunder was not heard2 but two miles nearer1 and in the same line1 it was just heard3 this latter station being on the summit of the range2 at ,holsworthy1 lying ,e4,n4,e41 it was heard as an awful peal2 at ,kilkhampton1 which lies directly ,n41 and separated by a broad broken valley1 the thunder was blamed with causing colts to break through a fence from terror1 and the distance is ten miles4 ,i am unable to give any further account either of the distance the thunder was heard1 or of the intensity of the light of the flash4 ,as the wind was blowing from the west1 with a slight bearing towards north1 the effect of the wind upon the sound is evident4 ,effect upon the pinnacle4--,the ,s4,w4 pinnacle 7,a7 was struck1 and apparently the effect of the lightning was not felt upon the two uppermost stones1 namely a small cross and a truncated cone1 which supports it at the summit1 both of granite4 ,it may be remarked that the entire facing of the tower is granite1 the interior masonry being made up of small stones of different kinds1 which exceeds #c feet in thickness1 while the blocks of granite which face the tower vary from #aj to #ab inches in thickness1 and in some cases are of immense size and weight4 ,as soon as the current could reach that part of the pinnacle which is made up of courses of separate stones1 the mischief commenced1 and the effect was to force the stones out all round the axis of the pinnacle1 so that in the same course many of the stones were separated by intervals of from #a to #e inches2 one great block1 measuring #b feet in length1 was thrown right out1 but fortunately fell outside the tower walls1 and left a gap in the pinnacle opening towards that quarter from which the storm came4 ,the entire pinnacle was shattered1 and all the courses of stones which make it up dislocated1 as well as the two courses of stones which lie beneath it4 ,the fierce rain storms had long ago washed away all the mortar from between the stones which compose the outside of the tower1 and probably every shower wets the interior of the masonry2 and this was especially the case at one part where there is a considerable leak of drainage from the roof of the tower4 ,illustration3 ,tower of ,church of ,week ,st4 ,mary1 ,cornwall ,effect upon the tower4--,the course of action of the current was from the pinnacle to this leakage1 where a stream of water was running down the wall and between the granite facing and interior masonry2 the downward course of the water was arrested by the belfry light1 and then has to fall to the masonry below the window2 just above the window a large block of granite ,c 7outside measurement #b feet by #ad inches71 was thrown out in such a way that it hangs like a halfopen door1 the projecting edge being that which lies just below the leakage1 and standing out about #aj inches from the wall2 across the belfry window runs an horizontal iron bar1 and at the bottom of the window lies an old iron bar2 the stonework beneath this bar was much knocked about4 ,from that spot the effect of the lightning disappears1 until it reached an immense carved granite block ,d1 which lies on the south side of the tower1 and very near its south-east corner2 and a few feet below this the leaden gutter ,e 7through which part of the roof drainage is poured to the ground71 runs some feet down the wall towards the earth1 but does not reach the earth by #ab feet4 ,the immense carved granite block is broken into two almost equal parts by a line parallel to its vertical edges1 and the two parts are separated by quite half an inch2 the fracture of the stone is not quite straight nor clean1 and the parts of the stone do not project beyond the surface of the tower4 ,i have been unable to trace the course farther2 it may have passed along #gj feet of leaden gutter1 between the nave and south aisle 7,f7 to the east end of the church1 or gone to ground at the base of the tower4 ,three or four days later1 during a very high wind1 a second stone fell from the pinnacle2 this same stone had been partially thrust out on a previous occasion in #ahfe4 ,upon examination the pinnacle was found to be in such a precarious condition that a single blow with a hammer on one small stone would have endangered the whole4 ,previous injuries4--,on ,october #aith1 #ahdc1 at #aj p4m41 the ,s4,e4 pinnacle 7,b7 was completely torn down1 and two courses of stones just beneath it were greatly damaged4 ,the line of action of the current was to the north-east edge of the tower1 towards the leaden gutter1 between the nave and north aisle1 over this it threw out a great block of granite2 from that point it passed along the leaden gutter and across the roof at the north aisle1 to a strong iron bar running vertically down the third out of the four north windows2 this window was considerably damaged1 and still bears marks of rough usage2 how it happened that two other windows near the tower1 and similarly fitted up with iron bars1 were passed untouched is a mystery2 to some extent all the windows in the church were somewhat damaged1 the framework being of wood they were much shaken1 and partially separated from the masonry4 ,this was probably caused by the effect of the current upon the air in the building3 the direction of the damage being due to the outward pressure4 ,in #ahab the north-east pinnacle was struck1 and also some little time before #afhh1 as there is a stone engraved with that date upon it1 and the date of the tower is the close of the fifteenth century4 ,the dates of these misfortunes have been as follows3-- ,about #afhh ,n4,e4 pinnacle4 #ahab ,n4,e4 pinnacle4 #ahdc ,s4,e4 pinnacle4 #ahfe ,s4,w4 pinnacle4 #ahgh ,s4,w4 pinnacle4 ,the north-west pinnacle appears to have escaped1 and it stands just over the tower stairs4 ,the south-east pinnacle1 which was struck in #ahdc1 was at that time surmounted by a weathercock4 ,there never has been a lightning conductor to any part of the church4 ,one word further4 ,i have been the holder of the benefice since the autumn of #ahgf2 last summer the specifications for the complete restoration of the church1 at a cost of #bjjj1 were sent to me by the architect2 before forwarding the same to the ,bishop of the ,diocese ,i supplied the omission of a lightning rod in the specification4 ,meteorological ,notes4--,it is a noteworthy fact that on each occasion during this century when a pinnacle has been struck1 the season has been between ,november and ,march1 with one electrical discharge during the storm4 ,it is also remarkable 7an experience founded certainly on only two summers1 but during that time the rule has been invariable7 that all round the neighbourhood summer thunderstorms may be passing in their usual fitful manner of storm and sunshine1 but immediately a summer thunderstorm passes over this village there is a complete break in the weather for eight or ten days4 ,rainfall4--#ahgg3 #diaa in41 #bac wet days2 #ahgh3 #dhjc in41 #bab wet days4 #c4 ,baker1 ,a4 ,j4 ,rosherville ,church1 near ,gravesend4--,the west gable of the south aisle was struck by lightning1 although close to the tower and spire which were provided with a lightning conductor1 and received no injury4 #e4 ,d4 ,brandon4 ,st4 ,ann's ,hotel1 ,buxton4--,in #ahge a chimney-stack was shattered by lightning1 the concussion in the flue drove fire and smoke into the drawing-room1 displaced the mantle-piece1 and broke many panes of glass4 ,the hotel occupies half a crescent1 the stack being in the middle of the crescent4 ,the building had no lightning conductor1 and there were no trees nearer than five or six hundred feet4 #g4 ,j4 ,colson4 ,twyford ,moors1 near ,winchester4--,struck by lightning in ,june1 #ahgh4 ,this building 7of which a plan is given7 was provided with one lightning conductor fixed to the tower4 ,the upper terminal branched into five points1 about four feet above tower roof2 the conductor1 which was -inch copper wire-rope1 was attached to the upper part of the tower1 with glass insulators1 and in the middle nailed to the wall through lead flashing1 then carried down rain-water pipe into cesspit4 ,the point of the building struck by the lightning was distant about sixty-four feet horizontally and sixteen feet vertically from the upper terminal of the conductor4 ,damage done was very slight1 tiles and laths being knocked off1 but no sign of scorching4 ,the conductor was not injured2 there are no trees near the building4 ,illustration3 ,plan and ,elevation of ,twyford ,moors1 ,winchester ,c ,conductor4 99 ,point struck4 ,p ,rain-water pipes attached to iron gutters4 #g;a4 ,st4 ,james' ,church1 ,west ,end1 ,hants4--,struck by lightning at #e p4m41 on ,june #abth1 #ahge4 ,the church stands on the top of a hill with many trees near1 it is built of brick with a lead ridge to roof1 iron and lead gutters1 iron rain-water pipes ,p1 and two iron chimneys4 ,the spire is of brick1 with stone angles fixed by iron cramps2 the spire was finished by an iron bar at the top1 but was not provided with a lightning conductor4 ,the damage done to the spire was considerable1 as shewn in the engraving1 making it necessary to pull it down1 but the tower was not injured4 ,stones from the spire were thrown through the trees at ,b1 which are #abf feet distant from the church1 cutting off some of the boughs4 ,the tree at ,a was untouched4 ,illustration3 ,st4 ,james ,church1 ,west ,end1 ,hants4 #ab4 ,t4 ,hawksley4 ,several ,steam ,chimneys not provided with lightning conductors2 upper portions knocked down1 chimney split or often skinned by the lightning1 i4e41 the four and a half inches of brickwork taken off2 details not given4 ,now uses ,gray's system of lightning conductors for such buildings1 which is found successful4 #ac4 ,a4 ,hill4 ,in ,south ,africa houses are generally roofed with corrugated iron1 and protected from lightning by planting a circle of high trees round them4 #ad4 ,g4 ,j4 ,hine4 ,all ,saints' ,church1 ,nottingham4--,struck about twelve years ago2 tower and spire #aej feet high1 with one conductor of half-inch copper wire-rope1 with platinum terminal1 and secured by insulated brackets1 but earth contact only two feet long at time of accident the rest having been stolen4 ,the lightning passed down the conductor till within six feet from the ground1 where it passed through a wall of solid masonry four feet six inches thick1 displacing some of the stones1 to an inch-iron gas pipe inside the church4 ,in passing off along the gas pipes under the floor1 it so far disarranged them as to cause a considerable leakage of gas1 which was set fire to by a candle some hours after the accident and exploded4 ,there were no trees1 only a few shrubs near4 #af4 ,j4 ,jerman4 ,alphington ,church1 near ,exeter4--,tower struck about ,march1 #ahbh2 the church had no lightning conductor4 ,the tower was rent through the masonry vertically1 damaging parapet and ungearing and injuring bells1 which were being rung at the time2 one ringer was killed1 and some of the others had the heel-plates melted off their boots4 ,there are few trees of any size near the tower1 which surmounts all adjacent buildings2 it had pinnacles and a weathercock on the top1 and a lead roof with spouts1 no down pipe4 ,very few casualties from lightning occur in ,devonshire4 #ah4 ,e4 ,j4 ,law4--,the tower1 surmounted by a cast iron vane1 of a house built under my superintendence1 was struck2 the slates stripped from the roof1 and the charge apparently escaped down the rain-water pipe2 it divided1 however1 and passed to an adjoining ridge1 chipped a piece off the iron cresting and hurled it some twenty yards from the building4 ,lightning conductor ordered1 but not erected2 cast iron ridges to all the roofs4 ,large infirmary within two hundred yards and high church tower within three hundred yards1 and houses nearer1 of equal height to the one struck1 and with cast iron crestings1 none of these were injured4 #ah;a4 ,st4 ,sepulchre's ,church1 ,northampton4--,vane on top of spire struck by lightning1 passed down the rod1 then to frame of one of the spire windows1 and thence to clock face1 from clock face it passed down the gas pipe1 leaving no further trace4 #ai4 ,t4 ,hayter ,lewis4 ,lewisham1 #ahgb4--,zinc chimney of house struck2 lightning went down flue ,a1 thence to a gasalier 7glass7 ,b1 broke it to pieces and passed harmlessly to the other end of the house where the pipe ended at ,c1 broke through a partition there and the window ,d1 and passed down the rain-water pipe ,e to the earth4 ,illustration3 ,,section4 #ai;a4 ,wandsworth1 #ahge4--;,chimney of house struck and damaged as shown in sketch1 lightning then passed along eaves gutter ,f1 and down the iron water-pipe ,g1 doing no further injury4 ,illustration3 ,,plan ,,and ,,elevation4 ,,plan4 #ai;b4 ,addiscombe1 #ahgh4--;,chimney struck above ,h1 the lightning passed down flue1 slightly injured the chimney-pieces1 and apparently passed through the two open doors to the road1 as the tenant standing at ,j distinctly felt a shock4 #ai;c4 ,forest ,hill4--,chimney 7,k7 struck1 lightning followed gutters shown by dotted line in sketch1 part no doubt escaped by pipe ,l1 but some passed along gutter to ,m doing slight injury to brickwork there1 the window ,n was broken1 and the gilt bead under cornice in rooms ,k and ,o was blackened4 ,illustration3 ,,plan ,,and ,,elevation4 #ai;d4 ,university ,college1 ,london4--,a chimney has been struck on two occasions1 but little damage done2 the lightning passed off by gutters and rain pipes which enter the drains2 the top of the dome1 which is of stone1 has escaped4 #ba4 ,j4 ,murgatroyd4 ,st4 ,mary's1 ,crumpsall1 near ,manchester4--,a lightning conductor from spire touched the eaves gutter1 and a gas pipe touched the end of this gutter4 ,the lightning passed from the conductor along the gutter to the gas pipe1 melted it1 and set the church on fire by igniting the gas4 #bb4 ,t4 ,oliver4--,never had a building damaged during thirty years practice2 uses inch copper rope for lightning conductors1 in contact with any iron work near1 and buried #h feet in ground in ashes4 #bc4 ,wyatt ,papworth4--,tall spire struck4 ,the church stands in an open position with no large trees near4 ,it was provided with an iron lightning conductor in4 diam41 fixed with iron holdfasts1 and carried down inside the spire and tower into ground2 the top of it was said to be attached to a bold copper finial on the spire about #aej feet from the ground1 and #ej feet above ridge of roof2 the lightning is supposed to have first struck the finial1 it slightly deranged some beds of masonry in upper part of spire1 then descended by iron rod to belfry1 melted a gas tube in the floor1 and set fire to the belfry by igniting the gas4 #bc;a4 ,house in country road4 ,the lightning struck chimney-pot1 descended flue to fire-grate and there divided1 one part passed to fire-grate below and damaged the gasalier1 another part destroyed a box of clothes near grate1 then passed out of door into another room1 struck the grate and passed into room below doing no further damage4 #bc;b4 ,another house situated at the corner of country road with high trees near1 lightning followed bell wires1 stripping paper1 c4 #bc;c4 ,at a third house1 chimney pot struck1 shaft and eaves gutters damaged4 #bd4 ,j4 ,l4 ,pearson4--,weathercock of a tall spire in an exposed situation struck4--,there was a wire rope conductor attached to the bar carrying the vane and passing down inside the spire and out at the belfry window1 the bells being connected with it2 it was attached to the tower by ordinary metal hooks1 and was carried #f or #h feet into the ground1 and about #aj feet from the base of the tower1 the strands being spread out4 ,the conductor was bent about very awkwardly under copings1 and in some places1 at right angles1 the damage was very slight1 and was limited to projections of mouldings close to a bend in the conductor about #bj feet above ground4 ,the conductor itself was uninjured4 ,some insignificant trees #ajj yards distant4 #bf4 ,e4 ,c4 ,robins4 ,st4 ,matthias's ,church1 ,brixton4--,no conductor1 although the church had previously been struck4 ,i have now put one up1 leading its lower end into a cistern of water4 ,the portland stone terminal cross was shattered1 and the stones of the cornice of the two topmost stages were displaced4 #bh4 ,h4 ,s4 ,snell4 ,the ,holborn ,union ,infirmary1 ,upper ,holloway1 in course of erection4--,conductor not fixed4 ,apex of tower roof1 #afj feet from ground1 having only roof timbers1 some lead-work ,a at apex1 and vane 7gilded iron7 fixed4 ,the damage commenced just below lead-work on apex1 and three out of four hips were much torn and shattered1 necessitating taking down and rebuilding2 the hips were each framed in three sections1 bolted together with iron bolts1 and in nearly every case the bolts seem to have specially attracted the fluid causing slight charring4 ,one of the dormer windows ,b was also separated from the spire4 ,the fluid appeared eventually to have been attracted by the water-pipes1 which rise to top story of building1 and so passed away4 ,it will be noted as peculiar that the iron vane was not touched1 and that the damage commenced immediately below it4 ,the damage evidently occurred only where the conducting materials were absent1 the iron vane and the lead would naturally bear no trace of injury4--,,ed4 ,no trees nearer than #aej feet1 and these much below the top of tower4 ,illustration3 ,view of ,tower of ,holborn ,union ,infirmary1 ,holloway #cb4 ,j4 ,b4 ,m4 ,withers4 ,detached house1 near ,sheffield1 in course of construction4--,no conductor2 the top of a chimney fifty-two feet six inches above the ground was struck and deranged but not thrown down4 ,the nearest ironwork was an ordinary cast gutter1 twenty feet from the top of the chimney4 ,no trees within sixty yards of the building4 #cd4 ,g4 ,wrottesley 7,col4 ,r4,e474 ,chimney shaft of a laundry at the ,barracks at ,gravesend4--,no conductor4 ,the chimney shaft1 forty feet high1 was entirely destroyed by a heavy charge of electricity as low down as the eaves of the building--at this point iron gutters went round the building and outside the chimney shaft1 and the charge passed harmlessly away to the earth by the rain water pipes ,p4 ,not a brick was left in place above and not one disturbed below the gutter2 the shaft appeared as if cut off by a knife at this point4 ,no trees within #ajj or #aej yards4 ,the disruptive force was so great that the bricks were scattered over a radius of #bjj feet1 and the slate roof was riddled like a colander by the brickbats4 ,illustration3 ,,elevation ,,and ,,plan4 #cf4 ,e4 ,n4 ,clifton4 ,bethnal ,green--,a four-roomed house1 one of a row1 with a ,v shaped roof1 was cut in two by lightning2 a fissure was made in the front and back walls1 and also in the middle plaster partition4 ,the fluid entered the house between the front windows and passed through the partition and back wall1 rather to the side of an iron pipe at the back which was the only metal near4 ,no trees in the neighbourhood4 ,,appendix ,e4 ,,particulars ,,of ,,accidents ,,by ,,lightning ,,collected ,,in ,,the ,,years #aheg1 #aheh ,,and #ahei ,,by ,,mr4 ,,symons1 ,,and ,,report ,,upon ,,the ,,same ,,by ,,prof4 ,w4 ,e4 ,,ayrton4 ,selected accidents4 ,i4 ,about a quarter past ten p4m4 on ,aug4 #ad1 #aheg1 an occurrence took place at the ,brick-lane station of the ,chartered ,gas ,company1 ,st4 ,luke's1 which caused some alarm4 ,it appears that the lightning struck one of the iron columns which supported one side of a gasometer1 or gas holder1 situate on the right hand side of the yard4 ,owing to the column having been thus struck by lightning1 the gas1 comprising many hundred thousand feet1 became ignited4 ,fortunately1 the services of the firemen were not required1 for1 owing to the admirable directions given by ,mr4 ,upward1 the superintendent of the works1 and the exertions of the men under him1 the flames were subdued in a comparatively short period4 ,fortunately no person was injured1 and no damage was done to any of the surrounding property4 ,,ii4 ,at half-past eleven on ,aug4 #ad1 #aheg1 there was a terrific discharge of lightning1 by which the south-east pinnacle of ,st4 ,michael's ,church1 ,stamford1 was instantaneously struck down4 ,the ,church of ,st4 ,michael is a modern structure1 erected in #ahcb4 ,it is situate in the centre of the town4 ,the south-east pinnacle1 which received the electric fluid1 was composed of a mass of masonry1 weighing about fifteen hundred weight2 the iron clamps or ties by which the work was bound together served as partial conductors4 ,at every break in their arrangement a series of disruptive discharges of the electric fluid took place in lateral directions1 driving out large masses of the stonework1 spreading them over the roof of the nave and churchyard1 doing considerable damage to the roofing and tombstones4 ,the effect of the fluid when it reached the base of the pinnacle1 from not meeting with a ready conducting medium1 was to uplift the whole mass imparting to it at the same time a kind of circular motion to the southward1 the apex of the pinnacle falling in a line with its original base2 and the base having traversed about the eighth part of the circle1 fell into the roof of the tower4 ,immediately at the base of the pinnacle there is a three-inch iron spout or tube erected to convey the water from the tower roof4 ,this iron tube the electric fluid entered1 and1 finding through it an unopposed channel1 passed down the tower1 and finally into the earth1 without doing more damage4 ,the iron tube or spouting in this instance1 and by mere accident1 acted the part of a lightning conductor1 and served to protect the other parts of the tower from most serious injury1 if not entire destruction4 ,,iii4 ,at ,walthamstow1 at #g4cj a4m41 on ,june #eth1 #aheh1 the flag staff of the church was shivered1 the gutters were torn up1 the robing room and various parts of the exterior injured1 and the gas pipes torn open4 ,,iv4 ,effects of lightning on a chimney stalk #bdj feet high4--,facts collected by ,alexander ,cruickshank1 #bhth ,june1 #ahei3 ,during the thunder storm at ,aberdeen1 between #h and #i a4m41 #bfth ,june1 #ahei1 the lightning struck ,messrs4 ,richard ,co's chimney1 #bdj feet high1 at ,rubislaw1 ,bleachfield1 one mile west of the city4 ,at the height of #abj to #adj feet three patches of surface bricks were torn off4 ,by the aid of a telescope and knowing the size of the bricks and the thickness of the mortar between them1 the two largest patches of denuded bricks were #g feet by #c feet and #d feet by #c feet--the longest measurements are vertical4 ,these patches were visible to the naked eye at least two miles off4 ,the parts denuded were #d inches thick1 or the breadth of a brick when placed with its largest surface horizontal and its sides external and internal4 ,every fourth layer1 however1 of the bricks have their ends placed external and internal with respect to the axis of the chimney1 and these bricks are broken across at the depth of #d inches1 or midway between their internal and external ends1 the latter being at the surface of the chimney4 ,thus three-fourths of the bricks of the denuded patches were torn off through the lime seam parallel to the surface of the chimney1 while a fourth of the number has been broken across in the same vertical plane4 ,another portion of the surface bricks1 #aj feet 7vertical7 by #c feet1 has not been entirely detached from the side of the chimney but forms a bulging of #a foot at its greatest projection1 and is visible in profile half a mile off4 ,the lightning on striking the chimney appeared like a cricket ball1 of the brightness of iron at a white heat4 ,this instantaneously passed into a bluish flame a little darker than that of common salt when thrown on the fire4 ,a momentary flicker and a hard crack were perceived4 ,the lightning seems to have struck the chimney #bj feet above the uttermost denuded patch at a small abraded spot occupying a few bricks1 and reddish when seen from the ground4 ,the chimney has no lightning conductor and the damage done has not affected its stability and draught4 ,additional remarks1 by ,alexander ,d4 ,milne1 chemist1 of ,rubislaw ,works4 #fth ,december1 #ahei4--;,half the lower bulging part1 where the force of the electric fluid seems to have become diffused or spent1 fell during the gale of #crd and #dth ,december4 ,the #crd inst4 had been frosty1 followed by thaw1 rain1 and wind from ,s4,w4 ,the part newly exposed is #aj feet in vertical height and #b feet across1 and the first mortar joint forms also the plane of separation1 the radial bricks being cut right across4 ,the lower edge of the patch is #ajj feet from the ground1 and the four patches extend upwards in an irregular line for #dj feet1 not vertically1 but in a spiral of about one-third round the circumference of the chimney4 ,the abraded spot through which the fluid seems to have penetrated is #bj feet farther up in the same oblique direction4 ,it seems to be about #f inches in diameter1 and the part appears as if broken by a hammer from the outside1 instead of being forced out from within1 as in the denuded parts below4 ,we may form a conception of the immense disruptive force exercised1 thus3 #aje bricks are torn off1 area of each #adths square inches2 total area1 #aefb square inches4 ,force or dead weight required to tear asunder3 #a square inch of brick has been found to be #cjj lbs4 ,total disruptive force #dfh1fjj lbs41 or #bji tons1 and this on the bricks cut across alone4 ,in addition we have a mortar joint three times the above area1 which at a moderate estimate of one-third the strength1 or #ajj lbs4 per square inch1 gives #bji tons more1 or #dah tons in all1 the approximate dead weight required to tear off what has fallen4 ,allowing for what is damaged but has not fallen1 the electric fluid must have had a momentary disruptive force of #ejj tons4 ,v4 ,gloucester1 ,july #bnd1 #ahei4--,two clumps of objects were struck1 two elm trees in the ,spa walks and ,rycroft ,chapel--with the adjoining elm4 ,this shows the lightning to have been forked1 as they were both struck at the same time1 and there was a double explosion of thunder2 the extremities of the fork were #adhj feet from each other4 ,the trees in the ,spa standing close to each other were stripped from a great height1 of six or seven inches width of bark1 which1 with the branches1 was strewed to the distance of several yards4 ,the elm at ,california had a large bough struck off2 the lightning then ran along another branch1 struck the stone edging of the roof of the chapel1 scorching the end of the bough and chipping great pieces off the stone2 it then ran along the metallic gutter to the end of the roof near the schoolroom1 where it descended the iron spouting to the ground1 bursting the spouting at the joints1 where it was a quarter of an inch thick1 and in one place knocked a hole in the wall ten inches deep1 as if some superior conductor had attracted it inside4 ,,vi4 ,i delayed answering your note until ,i could give you a correct description of the damage done to the chimney by examination from the scaffolding 7which we were erecting at the time of its receipt47 ,the chimney is a portion of some additions made to my manure works only last ,november4 ,it was struck during a fearful thunderstorm on ,tuesday the #aith of ,july1 about three o'clock in the afternoon4 ,the electric fluid detached about one-third of the topmost stonework1 which fell with great violence through the roof of the buildings below2 it then displaced and passed through the joints of the remainder of the stonework to the brick shaft4 ,this octagonal brick shaft it split and shattered in all directions on three of its sides1 for a space of about twenty-five feet1 completely detaching portions of the brickwork several feet in length1 both inside and out2 after which it split the remainder of the shaft asunder in a straight line through a further space of about fifteen feet to the stone base4 ,this stone base it also displaced 7passing through the joinings17 and through seven feet more solid brickwork1 to an open ventilator placed under the roof of a building at the foot of the chimney4 ,through the ventilator a portion of the electric fluid seems to have escaped from the chimney into the interior of a large warehouse1 some of the main timbers of the roof of which it has split and shattered very much4 ,a portion only of the fluid seems to have escaped in this way1 as the chimney is split below the ventilator for a further space of about ten feet4 ,several persons were at work in the warehouse at the time1 none of whom were injured in any way 7although they felt benumbed47 ,two strong horses standing in a cart were1 however1 struck down by the lightning on its escape from the warehouse4 ,the greater portion of the chimney must come down2 in fact1 we are now taking it down4 ,,john ,,sterriker4 ,driffield1 ,august #hth1 #ahei4 ,p4,s4--,in the construction of the chimney1 hoop iron was imbedded in the body of the brickwork every five or six courses1 to bind it together2 and this1 ,i think1 prevented the whole of the upper shaft from being thrown down1 although in many places the iron has been completely fused4 ,the total height of the chimney was #he feet4 ,extract from ,mr4 ,symons's report on ,thunderstorms in #aheg-eh and #ahei4 ,read at the ,oxford ,meeting of the ,british ,association1 #ahfj4 ,lightning ,conductors4--,no building provided with a conductor is recorded to have been injured during the three years2 in a few cases bars or pipes of metal acted as such1 so far as they extended4 ,the first instance was at ,wibsey ,school1 where the charge1 which killed one boy and injured eight others1 had passed safely down an iron pendant from the roof--in fact1 an iron rod of1 ,i believe1 small diameter4 ,in the case of a house in ,camden ,square1 the charge which overturned one end of a stack of chimneys1 passed safely down the iron water-pipe at the back of the house4 ,the flash which injured ,ryecroft ,chapel1 ,gloucester1 first struck an elm-tree close to the chapel and broke off a large bough1 it then darted to the roof1 ran along the metallic gutter to the end of the roof1 where it descended the iron spouting to the ground1 bursting the spouting at the joints1 where it was a quarter of an inch thick1 and in one place knocked a hole in the wall ten inches deep1 as if some superior conductor had attracted it inside4 ,i presume few persons will now oppose the results obtained by the elaborate investigations of ,sir ,w4 ,snow ,harris1 either as to the utility of conductors1 or their best form and distribution4 ,these points being admitted1 it remains to ascertain why they are not more generally used--why1 in short1 the accidents ,i have enumerated 7with1 perhaps1 as many more of which ,i have not heard7 are allowed to occur--that they are preventible there is no reasonable doubt4 ,i believe that the reason that conductors are so comparatively seldom used may be expressed by one word--expense2 a remark made by ,professor ,w4 ,thomson1 at the ,aberdeen meeting1 was a strong illustration of this point1 8,if ,i urge our manufacturers to put up lightning conductors they say1 #8,it is cheaper to insure than to put up conductors4'0 ,but as no insurance nor ought else can compensate for loss of life1 it becomes important to consider if any cheap and effectual substitute for a regular conductor can be found4 ,one plan for effecting this1 as far as private dwellings are concerned1 is that of connecting the lead gutters of the roof with the rain water pipe1 and with a rod projecting a few feet above the chimneys2 it is obvious that both gutters and pipe would derive additional conducting power from the water which 7at such times as the conductor is required7 is usually flowing along them4 ,i am not sufficiently acquainted with the laws of electric action to offer an opinion on this plan2 as far as my own limited experience goes1 ,i think it would be decidedly better than the entire neglect which now so largely prevails1 for it would probably induce the shock to pass down the outside of the house instead of down the chimney inside1 which has hitherto been its most frequent course4 ,i much wish that those who have turned their attention to electric action would express a decided opinion on the matter4 ,in one of the foregoing cases the iron pipe was perfectly competent and effectual in conveying the charge2 and in the other the damage 7limited1 be it remembered1 to bursting the joints7 doubtless arose from the intervention of the lead between the two lengths of pipe--considering the somewhat low conducting power of the lead1 such a result might almost have been anticipated4 ,kind of ,trees ,struck4--,in sixteen cases the class of tree struck has been mentioned2 of these one-third were elms4 ,the next in order of this unenviable distinction are the oak1 ash1 and poplar2 instances also occurred of the crab1 the lime1 and the willow being injured by lightning4 ,it is satisfactory to find that as far as so short a series is competent1 it corroborates previous opinions on the subject4 ,i may perhaps be permitted to quote one of the earliest with which ,i am acquainted4 ,in the year #aghg ,mr4 ,hugh ,maxwell wrote to the ,american ,academy that he thought he might state from his own experience that the elm1 chestnut1 oak1 and pine1 are often2 ash rarely2 and beech1 birch1 and maple never struck4 ,a communication with which ,i have been favoured by ,mr4 ,ingram1 of ,belvoir ,castle1 bears closely on this subject1 and is1 ,i think1 worthy of consideration4 ,he says1 8,i filed your letter1 resolving to keep a sharp look out in my rides about the neighbourhood for all the thunder-blasted trees4 ,it is of course difficult to obtain perfectly accurate information1 because trees are taken away after their destruction2 but ,i have ascertained that within the area of ,croxton ,park1 twenty per cent4 of the trees 7oaks7 have been struck by lightning4 ,the park is situated on high ground2 the substratum is rock 7limestone71 which has more or less iron in it4 ,the oaks1 where the soil is strongly ferruginous1 are useless as timber trees2 the wood1 when sawn1 splits and rives in every direction1 possibly from the quantity of iron40 99 99 99 99 99 ,the accounts given in the notes supplied to me by ,mr4 ,symons are of great interest1 but as the majority of the buildings struck had no lightning rods the details of the destructions do not bear immediately on the object of our ,conference4 ,there are1 however1 some few facts which may probably be of interest4 #a4--;,damp air although not a conductor for ordinary electricity 7see the writings of ,sir ,wm4 ,thomson7 may be a conductor for lightning3-- ,for there are many instances of sheep and horses being killed in open fields4 ,this may have been due to the sheep collecting together in a flock1 and the air above them becoming moist from the perspiration arising from the flock4 #b4--;,certain coincidences of earthquake waves and atmospheric electrical storms have been observed4--,the following may1 perhaps1 be one3-- ,june #eth1 #aheh4--;,during thunderstorm at ,pegwell ,bay the water in the ,bay1 the tide being then about two hours past flood1 suddenly receded about #bjj yards1 and returned to its former position within the space of about twenty minutes4 #c4--,open doors allow lightning to pass through4 ,august #abth1 #aheh1 ,bedford4--,the lightning passed through five open doors in its way from a chimney1 which was originally struck1 to an open window1 by which it went out1 all the doors being on the ground floor4 #d4--;,difficulty of making lightning conductors to protect buildings4 ,august #ahth1 #aheh4 ,neighbourhood of ,norwich--,a boy riding on a pony escaped unhurt1 while the pony was killed by lightning4 ,st4 ,peter's ,church1 ,brighton4--,the tower was provided with a lightning conductor1 but it was only carried up one of the pinnacles1 hence one of the other pinnacles of the tower was struck--the distance between the pinnacles being scarcely ten feet4 ,sometimes trees are struck in the middle1 and not at the top4 ,new ,kent ,road4--,while a man was sawing wood1 the lightning entered by the window1 struck the blade of the saw1 burnt the handle1 but did not injure the man4 #e4 ,a small body perfectly insulated from the ground is not safe from lightning4 ,october #aath1 #aheh4 ,kilham1 ,yorkshire4--,two sea gulls1 while flying1 were killed by lightning4 #f4 ,advantages of lightning conductors4 ,during #aheg1 -#eh1 -#ei almost the whole of the buildings reported as damaged by lightning were unprovided with lightning conductors4 ,among those struck but not damaged were buildings on which metal bars or pipes acted as conductors as far as they went1 proved by the lightning having burst the metallic spouting at the joints4 #g4 ,expense of ,conductors4 ,sir ,w4 ,snow ,harris' rule3-- ,copper solid #je in4 in diameter tube #ae in4 in diameter in4 thick4 ,iron solid #jge in4 in diameter tube #bjj in4 in diameter in4 thick4 ,minimum cost one shilling per foot1 not including cost of carriage and fixing4 99 99 99 99 99 ,sir ,william ,thomson1 at the meeting of the ,british ,association at ,aberdeen1 said 8,if ,i urge on ,glasgow manufacturers to put up lightning conductors they say it is cheaper to insure than to do so40 ,this shows the importance of economy in the construction of conductors1 and consequently of the determination of the least expensive conductor1 which will be safe for any special building4 ,one of the most important points to determine1 it appears to me1 is whether an electric current1 when the electro motive force is very high1 passes along the surface or through the body of a conductor1 since on the result of this must depend whether we give a lightning conductor large surface1 or large sectional area--in fact1 whether a tube of large diameter1 but with comparatively thin walls1 is better than a solid rod of much smaller diameter4 ,in the ,may number for this year of the ,philosophical ,magazine1 there appeared an interesting article1 by the late ,mr4 ,brough1 8,on the proper ,relative ,sectional ,areas for ,copper and ,iron ,lightning ,rods10 in which ,mr4 ,brough arrived at the result that the sectional area of an iron rod conductor should be to the sectional area of a copper rod in the ratio of #h to #c2 from which he concludes that an iron rod will be the cheaper conductor4 ,but this result is obtained on the assumption that the resistance of rods of the same length1 and of the same material for lightning1 are inversely as their sectional areas1 a result about which ,i think there may well be doubt4 ,w4 ,e4 ,,ayrton4 ,,appendix ,f4 ,,abstracts ,,of ,,printed ,,documents4 ,,french ,,official ,,publications4 ,preliminary ,note4 ,in #aghd1 the attention of the ,french ,government having been directed to the desirability of protecting the powder magazines of the kingdom from damage by lightning by the employment of conductors1 a system of construction was proposed by two officers of the ,engineers and ,artillery4 ,this system was referred by the ,minister of ,war to the ,academy of ,sciences for consideration and report4 ,from time to time subsequently other proposals of a like nature1 and other inventions and improvements in the construction of lightning rods were considered by the ,academy1 and reported upon by various ,committees4 ,at the request of the ,conference1 ,i have endeavoured1 in the following pages1 to give in as condensed a form as possible an accurate abstract of their contents1 and to avoid1 in all cases1 the expression of any opinion1 either adverse or concurrent1 upon the principles or suggestions contained in them4 ,e4 ,e4 ,,dymond4 ,,report made to the ,,academy ,,of ,,sciences1 by ,,franklin1 ,,leroy1 ,,coulomb1 ,,de ,,la ,,place1 and ,,rochon4 #bdth ,april1 #aghd4 ,certain proposals for erecting lightning rods for protecting the powder magazines at ,marseilles having been submitted to the ,academy for their opinion1 a committee1 consisting of the above-named1 was appointed to examine and report4 ,they begin by enunciating the theory which should regulate the erection of conductors1 and they lay down the following rules3-- #a4 ,the extent of the building should first be ascertained to decide whether one or more conductors should be used4 ,electrical experiments had not yet made known anything of the extent to which the action of the point of the conductor reached4 ,but since buildings had been supplied with conductors many observations had shown that those parts of them which were more than #de feet ,french 7#dh ,english7 from the point of the conductor had been struck by lightning4 #b4 ,when there are many points or arrows on the building they should be connected together and also connected with all parts of the roof which are covered with lead1 and also connected with the weathercocks or ornamental metal points so as to form one metallic system with the conducting bars4 #c4 ,it is not less important that these bars should be thoroughly joined together2 for a solution of continuity in them produces a resistance to the passage of the electricity according to the extent of their separation4 #d4 ,it is necessary that the bars should communicate thoroughly with moist earth or1 better still1 with water4 ,as to the height of the points they should be at least #ab or #ae feet 7#ac to #af feet ,english71 or even more if the building is a large one4 ,it is certain that the higher they are the wider the extent of their action4 ,they should be #b inches 7#bb ,english7 square at the base and greater in proportion as their height exceeds #ae feet 7#af ,english74 ,if the conducting bars are #h or #aj lines 7or1 say #a inch7 square1 it will be more than enough4 ,no case had occurred in which iron bars of this size had been in any way damaged or altered by the passage of lightning4 ,the reporters then proceed to examine the two proposals for protecting the powder magazines at ,marseilles1 sent in by ,m4 ,ravel de ,puy ,contal and ,m4 ,pierron4 ,they were both for the same building which was #ca toises long and #h toises wide 7about #aih by #ea ,english feet74 ,the first provided for the erection of three points on the ridge of the roof1 and of four others1 one at each angle of the building2 the second had also three points on the ridge1 but the other four were alternated on the two sides of the roof1 and iron bars were carried all along and connected with all the points4 ,the manner in which the terminals were fastened to the roof and the conducting bars fastened together and led to the water was the same in each proposal4 ,the reporters remark concerning the second that the conducting bars laid horizontally along the roof would involve a great and unnecessary expense1 but the points should be retained1 only instead of placing them alternately they should be set up so that each of them was half way between the middle and the end of the roof1 and instead of connecting these points by bars along the length of the roof1 they should be connected with the one connecting the three points on the ridge by bars joining it perpendicularly4 ,as to the method proposed for joining the several parts together the reporters cannot help thinking that in their desire to make thoroughly good connections ,,mm4 ,pierron and de ,ravel had proposed a plan involving too much difficulty and superfluous expense ,it seems to have been proposed to screw the bars into each other1 and they recommend instead of this to make at the base of each point1 immediately above its insertion into the roof1 a circular flange about #b inches in diameter and #b lines thick1 with a hole half an inch in diameter in the middle and at the ends of each conducting bar to make a similar flange and to bolt the flanges together with a sheet of lead between them4 ,crutches should be fixed on the roof to carry the conducting bars4 ,the points should be fixed three on the ridge and two on each side of the roof half way between the point in the middle and that at each end4 ,these four should be connected with the conducting rods running along the ridge and should overtop the ridge by at least #f feet 7#f feet #e inches ,english74 ,by this arrangement all parts of the roof would be well protected4 ,the reporters highly approve of the way in which the conducting bars are connected with water by being led into the sea1 but if at the other end of the building there is sufficient earth on the surface1 and the soil is not entirely rock the conductor from the point placed at that end might be led into it4 ,it is recommended that the points of copper should be screwed to the terminals for convenience of removal when necessary4 ,,report made to the ,,national ,,institute1 by ,,leroy1 ,,la ,,place1 and ,,coulomb1 on a ,lightning ,rod for ,powder ,magazines proposed by ,,regnier4 #f ,nivose1 ,year #h 7#bcrd ,december1 #aghi47 ,the reporters think it desirable to make some general observations on lightning rods1 the rather that it appears that some persons have had fears as to the certainty of their effect4 ,it is impossible to reject the theory upon which ,franklin had proceeded in providing lightning rods for the purpose of protecting buildings from damage by lightning4 ,still1 as the theory needed to be confirmed by facts1 it might at first have been doubted whether the lightning rods were really effectual2 but now that observation1 and experiment had proved the truth of the theory there was no longer any room to question their utility4 ,it may even be remarked that observations had not only proved that they were effective when well constructed1 but that they conducted the lightning down without accidents1 even when they had some defects1 which might have caused one to doubt their efficacy4 ,the defects alluded to were a blunted point and a break in the continuity of the conductor4 ,with reference to these two cases observations have shown--#ast4 ,that although the points have been blunted1 they still attract the lightning from the clouds to themselves in preference to the surrounding objects4 #bnd4 ,that although the several parts of the conductor are not thoroughly joined together1 the lightning will still1 if the break be not too considerable1 pass along the conductor without accident4 ,in support of the first proposition they quote the observations of ,doctor ,rittenhouse1 of ,philadelphia1 who had examined several of the points in that city1 and had found them melted1 showing clearly that they had been struck by lightning1 and probably more than once1 as it had been shown by many observations that where1 from local circumstances 7not then fully ascertained17 lightning had struck in certain places or on certain buildings1 it was not uncommon to see it strike again2 and a number of observations of a different sort had shown that lightning was attracted by metals on buildings even when they were but slightly pointed1 such as tin weathercocks1 or iron crosses1 and even plain sheets of iron4 ,one of the most striking examples in support of the second proposition1 was the case of an ,american ship1 reported in the ,phil4 ,trans4 for #aggj4 ,during the night1 in the midst of a storm1 the crew reported that there was a stream of fire in the rigging1 just above the middle of the lightning conductor4 ,the captain saw a stream of fire1 sometimes in sparks1 and sometimes only a steady light2 and on examining the conductor next morning1 found that one of the links of its chain was broken4 ,fortunately the two pieces1 being kept in place by the fastening to the shrouds1 were only about three quarters of an inch apart4 ,these two broken ends formed a sort of points1 and on its passage between them the lightning had become visible4 ,but this was all2 no shock was felt1 nor anything which caused any suspicion that the fracture of the conductor had in any way hindered the passage of the lightning4 ,franklin also had shown by experiment that in a lightning rod where the upper end was only connected with the part entering the ground by a very fine brass wire1 although the wire was melted by the passage of the lightning1 it still was conducted from top to bottom without any damage to the house2 and in other instances metallic wires1 though partly melted by the lightning1 had still served as conductors4 ,but it is not contended from these examples that a very exact and continuous connection of all the different parts should be dispensed with4 ,the lightning rod proposed by ,regnier consisted of a piece of wood1 coated with resin1 rising #b metres 7#f feet #g inches7 above the roof1 and having fixed on its top a sort of inverted funnel of copper1 at the upper end of which was fixed the point4 ,to the lower edge of the funnel were fastened ropes formed of twenty-seven annealed iron wires well bound together1 which were1 at a suitable distance1 connected with iron bars1 fastened to masts1 and leading to moist earth4 ,the point had a small piece of platinum at its upper end4 ,illustration3 ,regnier's ,system of ,lightning ,conductors ,the reporters observe that the wooden support may be employed by way of extra precaution1 though there was no known instance of lightning leaving metal for wood2 but it should be strong enough to resist the wind4 ,they approve of the method proposed for connecting the point with the metal bars1 metallic ropes being very suitable for this purpose1 and keeping them well away from the building was quite right2 but they add that the metallic bars should not only communicate with moist earth1 but also with water in wells or otherwise4 ,,instructions ,,for ,,erecting ,,lightning ,,rods ,,for ,,powder ,,magazines1 adopted by the ,,fortifications ,,committee4 #beth ,august1 #ahjg4 ,a lightning rod is an electrical conductor terminating in a point and carried down to the common receiver4 ,it may be regarded as a metallic tree1 and divided into 7#a7 the upper terminal1 7#b7 the trunk1 and 7#c7 the roots4 #a4 ,the upper terminal is a very pointed1 conical or pyramidal spike of metal having a base #c or #d centimetres 7#a inches7 in radius4 ,the point is of gold or platinum1 soldered to a copper rod #a or #b metres long 7#c feet #c inches to #f feet #g inches74 ,this rod is joined to the rest of the upper terminal1 which is of iron1 either by solder1 a screw1 or a pin4 ,it is important that all the parts of the upper terminal should be joined with care so as to prevent fracture2 at the bottom of the terminal are several feet by which it can be leaded to the vault or bolted to the framing of the roof4 ,several devices for giving some play to the terminal so as to diminish the effect of vibration have been proposed1 but it is better to make the terminal strong enough to resist4 ,at the bottom of the terminal is joined the piece connecting with the conductor2 this ought to be very complete and continuous1 especially at the point of junction with the terminal4 ,frequently the terminal is enlarged at this point to facilitate the passage of the lightning4 ,to preserve the terminal from rust it is sometimes gilded--it has been proposed to tin it--more frequently it is merely painted2 experience shows that this is sufficient4 ,instead of making the whole terminal conical or pyramidal1 a square bar of iron1 finished with a point of copper tipped with gold or platinum1 is sometimes used4 ,this plan may usually be adopted without danger1 but they are more liable to be broken or bent by vibration4 ,illustration3 ,,fig3 #a4 ,illustration3 ,,fig3 #b4 ,illustration3 ,,fig3 #c4 ,illustration3 ,,fig3 #d4 #b4 ,the trunk or conductor is made of iron bars #ac to #bj millimetres square 7 to inch7 notched at the ends and bolted together with a plate of lead between the two 7,fig4 #a74 ,for powder magazines a bar of #bg millimetres 7#a inch7 square is recommended4 ,they follow the outline of the roof1 cornice1 and wall1 and each bar is fixed by a half collar 7,fig4 #b7 or cramp placed in the middle of the bar or as far as possible from the junction of two bars4 ,instead of the iron bars ropes of copper or iron wire1 or even of hemp1 may be used2 these last may be used provisionally1 but for permanent conductors they have no advantage either in economy or conductivity4 ,the copper rope conducts the lightning better1 but its smaller size and cylindrical form1 by diminishing its absolute and relative surface1 counterbalances its superior conductivity4 ,the great and real advantage of metallic1 and especially of copper ropes1 is in their continuity and their flexibility4 ,the conductor is led down to the surface of the ground where it is bent and led parallel to the surface towards a pit full of water1 or deep enough to allow the end of the conductor to rest in damp earth2 from #b metres 7#f feet #f inches7 above the ground to the pits the conductor is enclosed in a channel or trough like the fuse of a mine1 the object of this is to protect the conductor from the dampness of the soil and from contacts4 ,these would be unimportant so long as there is a perfect connection between the point of the conductor and the common reservoir1 but this continuity may be destroyed by degradation of the conductor1 and it is chiefly at the joints that this discontinuity is to be feared4 ,when the conductor has to be buried it should be in an oaken trough1 well put together and tarred or charred or surrounded by powdered charcoal so that the metal cannot be rusted by infiltrations or humidity2 in some soils it is better to make the subterranean part of the conductor of lead1 taking care by increasing the surface to make up for its inferior conductivity4 ,sometimes water pipes may be made use of1 but only when they serve to lead water away and when they terminate in an isolated reservoir4 ,it is important to lead the conductor far away from water pipes carrying water to public fountains or into the interior of houses4 #c4 ,if the conductor leads to a well full of water the roots 7,fig4 #c7 need not be more than a few spindles terminated in points and long enough to be always immersed4 ,when the conductor only leads to a bed of earth it is supplied with a system of roots 7,fig4 #d71 having for its object the multiplication of the points for the escape of the lightning1 and these are increased in number according as the soil is a less good conductor4 ,the pits should be some distance from the foundations of the building1 so that the lightning may not damage them1 and it is important1 by all possible means1 to increase the natural humidity of the soil4 ,when the wells cannot be closed it is necessary that the conductor should be insulated and plunged deeply in the water for fear that the communication of the electricity to the well-chains or pump-rods might cause accidents or alarm4 ,after some other instructions it is added that the dispersal of the electricity in the common reservoir is1 next to the continuity of the conductor1 that which most deserves the attention of the physicist and the engineer4 ,it has been remarked that a point extended its sphere of activity as far as #aj metres 7#cb feet #i inches71 that beyond this distance its effect became less sensible1 and that when the points were too near together they neutralised one another4 ,so upon a building of a given size it is necessary to set up so many that all parts shall be covered by their spheres of attraction1 which should meet and not overlap each other4 ,lightning in passing from a cloud to the earth does not always take a vertical direction1 it sometimes follows the path of the rain drops1 which is inclined by the wind1 so when a magazine is very lofty1 or on an elevated spot it is not useless to fix horizontal or inclined points on the gables or angles4 ,in some places the magazines are dominated by other buildings2 in these cases the neighbouring buildings should be protected1 or the magazines should have horizontal points towards them4 ,if the ramparts dominate the magazine it will be prudent to set upon them a lightning rod on a mast4 ,trees are only struck by lightning because their tops serve as points but their trunks are bad conductors1 hence it is prudent not to have plantations1 especially of lofty trees near magazines4 ,however many points may be set up on a magazine they should all be connected together1 and all joined to the principal conductor1 and it would be well to have more than one principal conductor so that if one loses its continuity the lightning may have a path by the other4 ,stone1 wood1 and gunpowder are bad conductors1 and pieces of metal may without danger be used in the inside of magazines1 provided they are connected with the principal conductor by branch conductors of suitable size3 still it is prudent to keep the metal outside4 ,illustration3 ,powder ,magazine1 with oblique as well as vertical rods ,reference is then made to 8,regnier's ,system of ,lightning ,rods10 ,appendix ,f41 p4 #ec1 which is thought to be much too expensive4 ,,report on the foregoing ,instructions made by ,,la ,,place1 ,,rochon1 ,,charles1 ,,montgolfier1 and ,,gay ,,lussac to the ,,national ,,institute4 #bnd ,november1 #ahjg4 ,the reporters say that experience has taught that the point of a lightning rod #d or #e metres 7#ac to #af feet7 does not effectually protect a space round it greater than one having a radius of #aj to #ab metres 7#cb to #ci feet74 ,that when there are points or considerable masses of metal on a building having a lightning rod it is absolutely necessary to connect them by branches with the principal conductor4 ,that it is not less important that the metallic bars should be thoroughly well connected together so that the electricity may find no resistance in its path from the point to the common receiver4 ,and lastly1 that it is necessary that the conductor should have a perfect communication with moist earth1 or better1 with water4 ,they then proceed to discuss the instructions1 or that part of them which relates to the construction of the lightning rods4 ,they recommend the use of gilded copper points1 notwithstanding the doubt concerning them which had been raised in consequence of their deterioration by oxidation1 and their being blunted by lightning4 ,they say that experience has shown that an iron rod #bj millimetres 7#h inch7 square is more than sufficient to carry the most violent discharge of lightning1 and that it is consequently needless to make them larger1 as recommended in the ,instructions2 that it is only at the joints that there is any cause for fear because1 in spite of the insertion of the piece of lead1 the contact is not perfect2 that it would be easy by enlarging the bars at their junctions to increase the number of points of contact1 and by lengthening the bars to make fewer joints4 ,that in this respect the use of iron wire ropes would be very advantageous1 but they fear that the ropes would be easily destroyed1 and that the use of copper wire rope instead of iron would be too expensive4 ,when the conductor reaches the ground too much care cannot be exercised in making a free communication between it and the soil4 ,it is upon this that its good effect principally depends1 for houses have been struck although provided with a conductor1 because it only communicated with a very dry soil4 ,m4 ,patterson1 of ,philadelphia1 in the fourth volume of the ,american ,phil4 ,trans41 has published a means of making a good contact which seems useful4 ,he proposes to lay the conductor in a bed of galena worked into a paste with melted sulphur4 ,the galena is a good conductor1 and would have the advantage of protecting the iron from the damp4 ,he has also proposed a simple means of providing for the easy dispersion of the electric fluid in cases where the soil is not very damp1 which consists in making a hole in the ground and filling it with charcoal1 into which the conductor is plunged4 ,but ,m4 ,guyton used the conducting power of charcoal for this purpose more than thirty years ago1 and it has been applied in many ways4 ,charcoal1 like galena1 is a good conductor1 and this property renders its employment desirable in cases where the soil is dry4 ,upon the proposal to fix inclined or horizontal points they think that vertical points will suffice2 and with reference to the ,regnier system1 they remark that it would certainly be very expensive1 and that it would not be necessary to adopt it until the usual system had been found insufficient4 ,,instructions about ,,lightning ,,rods adopted by the ,,academy ,,of ,,sciences4 ,first ,part1 #bcrd ,april1 #ahbc4 ,,prepared ,,by ,a ,,committee ,,consisting ,,of ,,mm4 ,,poisson1 ,,lefevre-,,gineau1 ,,girard1 ,,dulong1 ,,fresnel1 ,,and ,,gay ,,lussac4 ,illustration3 ,mode of attaching ,conductor to ,upper ,terminal ,after some theoretical remarks the ,committee describe the conductor they recommend1 giving the name of tige 7upper terminal7 to the part rising into the air above the roof1 and that of conductor to that part extending from the upper terminal to the ground4 ,the upper terminal is a square or round bar of iron tapering from base to summit4 ,if from #g to #i metres 7#bc feet to #bi feet #f inches7 high1 which is the smallest height to be used on large buildings1 it should be #ed to #fj millimetres 7#ba to #bc inches7 square or diameter at the base1 if #aj metres 7#cb feet #i inches7 high1 it should be #fc millimetres 7#be inches74 ,about fifty-five centimetres 7#a foot #i inches7 of the upper end is cut off and replaced by a point of copper either gilded at the end or tipped with a little piece of platinum4 ,at the lower end of the terminal 7,a71 #h centimetres 7#cae inches7 above the roof1 is fixed a base 7,b7 to throw off the rain which would run down the terminal1 and above this base the terminal is clasped by a collar 7,c71 as shown in the drawing1 to which is bolted the conductor 7,d74 ,the engraving shows the modification of the arrangement as adapted to both round and square terminals4 ,the conductor is a bar of iron #ae to #bj millimetres 7#ei to #gi inches7 square1 joined firmly to the upper terminal by bolting it tightly between the two ears of the collar4 ,the best way of joining the bars together is shown in figure #a1 p4 #ee4 ,it is to be held up at a distance of #ab to #ae centimetres 7#dg to #ei inches7 from the roof by crutches1 and to be kept at a like distance from the walls of the building4 ,at #ej or #ee centimetres 7#aif to #baf inches7 below the surface it is turned away perpendicularly from the wall for a distance of #d or #e metres 7#ac feet #a inch to #af feet #e inches7 if it does not sooner meet with water4 ,to avoid rusting the rod is carried in a trench filled with charcoal1 and then turned down a well so as to have at least #fe centimetres 7#beg inches7 in the water when at its lowest level1 where it terminates in three or four branches to facilitate the exit of the electricity from the conductor4 ,if there is no well convenient1 a pit should be made #ac to #af centimetres 7#ea to #fc inches7 in diameter1 and #c to #e metres 7#i feet #aj inches to #af feet #d inches7 deep1 down the middle of which the conductor should be led and the hole filled with charcoal tightly rammed4 ,as the iron bars forming the conductor are not easily bent to follow the lines of the building a metallic rope may be used4 ,it is made of four strands1 each composed of #ae iron wires1 and forming a rope of #af or #ah millimetres 7#fb to #g inches7 in diameter4 ,each strand is tarred separately1 and the whole also well tarred when put together4 ,it is attached to the upper terminal in the same way as the bars by pinching between the ears of the collar 7c74 ,at #b metres 7#f feet #g inches7 above the ground it is joined to the bars which form the earth connection by being pinned into a socket formed at the end of the first bar4 ,ropes of copper or brass wire may be used1 and they need not be more than #af millimetres 7#fb inches7 in diameter4 ,it is necessary to connect any considerable metallic masses 7lead roofs1 metal gutters1 or tie rods7 with the conductor1 because if this be not done1 and the conductor be broken1 or have a bad earth connection1 the lightning may leave the conductor for the metallic mass4 ,modifications of this form of conductor for use on churches1 ships1 and powder magazines 7for the latter carrying the conductors on masts is recommended7 are then described4 ,the report says that the terminal of a conductor protects efficiently a circular space round its base1 having a radius equal to twice its height2 but that it is prudent to estimate that a conductor on a church spire only protects a circle having a radius equal to the height of the conductor4 ,the conductor should go the shortest way to earth4 ,it should be on the side most exposed to the weather1 especially on spires4 ,second ,part1 #ahth ,december1 #ahed4 ,,prepared ,,by ,a ,,committee ,,consisting ,,of ,,mm4 ,,becquerel1 ,,babinet1 ,,duhamel1 ,,despretz1 ,,cagnard ,,de ,,latour1 ,,and ,,pouillet4 ,notwithstanding the considerable advance in knowledge since #ahbc1 the instructions of that date have no need to be altered1 at least in their essential principles2 but the methods of construction of buildings having materially altered1 and metal having largely replaced wood and stone1 buildings had1 so to speak1 become metallic masses1 which would have incomparably greater attraction for thunder clouds4 ,the ,palais d'industrie in the ,champs ,elysees1 for example1 nearly #c hectares 7#gd acres7 in extent1 and #dj metres 7#aca feet7 in height had everywhere enormous masses of iron1 brass1 and zinc4 ,the company undertaking the building had sought the advice of the ,academy as to the means to be employed to protect it from lightning1 and it had been found necessary to revise the instructions of #ahbc1 in order to introduce such modifications as were necessary4 ,quoting the passage referring to the connecting of metallic masses with the conductor1 the ,committee think that the time had come to enter into fuller details on this point4 ,formerly the use of metal was almost restricted to ridges1 gutters1 and tie rods2 now metal was used everywhere1 and what is important1 in large surfaces and great masses2 and this new system realised on a large scale the first objection to lightning rods--it attracts the lightning4 ,when this objection was applied to lightning rods1 it had only the appearance of truth1 but when applied to the masses of metal then used in buildings1 it was not only specious1 but true1 and founded upon well established laws2 these buildings do attract the lightning1 and render its effects more disastrous4 ,in the case of two buildings alike in size and shape1 situated on the same soil1 one made of wood and stone as formerly1 the other with much metal as now1 and both without lightning rods--if the conditions are such that the lightning must discharge itself1 it will always strike the latter1 and never the former2 in the same way as on bringing to the conductor of an electrical machine a ball of wood or stone1 and one of metal1 it is always the latter which will receive the spark4 ,lightning rods1 therefore1 are so much the more indispensable as the buildings contain greater surfaces and greater masses of metal4 ,the nature of the soil must be taken into account1 as well as the buildings and other objects upon it4 ,a dry soil1 with a subsoil of dry sand1 chalk1 or granite1 does not attract the lightning1 because it is a bad conductor4 ,unless when accidentally wetted the buildings on it participate to some extent in this immunity1 at least if they are not built in the modern style1 and are not very large4 ,but if there are at a moderate depth underneath this dry ground1 large metallic veins1 vast caverns1 sheets of water1 or only abundant springs--these will attract the lightning1 which will destroy everything in its path unless protected4 ,if the wet or metallic strata are very deep1 the danger of an explosion is diminished by the difficulty of passing the intervening envelope1 and by the weakening of the action of the cloud by the increase of distance4 ,on the #aith ,april1 #ahbg1 the packet boat ,new ,york was twice struck by lightning4 ,on the first occasion1 having no conductor1 it received considerable damage2 on the second1 the conductor was fixed2 it was made of a pointed bar of iron1 #ab metre 7about #d feet7 long1 and #aa millimetres 7#dc inch7 diameter at the base1 and a surveyor's chain about #dj metres 7#aca feet7 long1 forming a connection between the foot of the rod and the sea2 the chain was made of iron wire #f millimetres 7#bd inch7 in diameter2 the links were #de centimetres 7#agg inches7 long1 ending in loops1 and joined together by two round rings4 ,when struck the chain was dispersed in burning fragments and globules1 which set the deck on fire in many places1 notwithstanding the hail upon it and the rain which fell heavily2 the bar at the top was melted for a length of #cj centimetres 7#aah inches7 from the point1 and down to a diameter of #f millimetres 7#b inches74 ,the rest of the rod remained with about #h centimetres 7#ca inches7 of the chain attached to it1 the longest piece of chain found was less than #a metre 7#c feet #c inches7 long1 and was blistered as by fire4 ,on the #acth ,june1 #ahed1 the ,jupiter was struck by lightning4 ,the conductors were in place2 that of the mainmast which was struck went #b metres 7#f feet #f inches7 into the sea1 and had at its end a ball #b kilos in weight4 ,after being struck the conductor had disappeared and the pieces of it were scattered everywhere4 ,the conductor1 about #gj metres 7#bcj feet7 long1 was a cable of three strands formed of sixty brass wires1 each one half or two-thirds of a millimetre 7#jai or #jbf inches7 thick4 ,the cable was mostly in bits no bigger than pins1 but there were some pieces a few decimetres long1 these had been turned violet colour as by fire1 and those first touched were still burning hot4 ,these two examples show that a conductor may be destroyed1 but they also show that it is not useless even then1 since it will have received the discharge and directed it1 and so prevented greater mischief4 ,the ,jupiter received no damage2 whilst not far off1 a ,turkish vessel1 which also had a conductor 7but the chain of which did not reach the water7 having been struck by lightning in the same storm1 had a hole more than #cj centimetres 7#aah inches7 deep1 and almost such as would have been made by a cannon ball1 in her side just above the copper1 and near the water line4 ,the question is1 are such accidents to conductors inevitable1 or are they the result of faulty construction8 ,all the facts established in the accounts of lightning and its phenomena1 leave no doubt on this point4 ,all the lightning rods which have been destroyed were of bad materials1 insufficient1 badly constructed1 not in accordance with the principles which theory has deduced from experience4 ,the conductor of the ,new ,york had several faults2 its upper terminal was too small1 and too much drawn out2 its conductor had much too small a sectional area2 and the use of a chain in such cases should be strictly excluded4 ,there is no example known in which lightning has been able to melt iron rods #b centimetres 7#gh inch7 in diameter1 or #c square centimetres 7#aah inch7 in section2 and copper may be used in still smaller sizes4 ,the conductor of the ,jupiter1 although better than the former1 had also a radical defect4 ,the fragments of the conductor which were examined bore but few traces of fusion1 and none of these traces extended to the entire thickness of the cable2 they were also limited to a group of some of the sixty wires of which it was composed4 ,this seemed to show that the discharge was not carried equally by all the wires1 and that those wires which it followed being insufficient to carry it1 were the ones melted1 and the others were broken or volatilised with explosion4 ,hence the breaking of the cable and dispersion of fragments of some decimetres in length1 which1 though too hot to be touched1 were not hot enough to set wood on fire4 ,this explanation1 however1 raises a singular question1 whether1 in a cable of similar wires twisted and bound together1 the lightning can choose some wires in preference to the rest1 even when the whole of them are hardly sufficient to give it a free passage4 ,undoubtedly1 yes2 at any rate under certain conditions4 ,no doubt if at both ends of the cable1 for the length of a decimetre1 the wires first tinned separately are afterwards soldered together1 so as to make a sort of metallic cylinder1 electricity1 whether natural or artificial1 having to pass along the cable1 will not show a preference for one wire over another2 but where this is not done--if at the two ends1 or1 more generally1 at the two points of junction with other conductors1 the wires are isolated by layers of dust or oxide--if1 in addition1 the cable only touches the terminals by its outside wires1 then things happen very differently4 ,the electricity takes those wires that are in contact with the terminal2 these reduced to few in number become incapable of carrying it2 and the whole cable broken by the explosion exhibits the phenomena shown in the case of the ,jupiter4 ,the deficiency in each case was due to one cause--insufficiency of sectional area4 ,in the first case the insufficiency is apparent1 the iron wires #f millimetres 7#bd inch7 thick were nine or ten times too small2 in the second1 the insufficiency is more hidden1 it results from badly made junctions4 ,the two most fundamental rules for the construction of the rod and conductors are--#ast4 ,that they shall have a sufficient sectional area4 #bnd4 ,that they shall be continuous and without a break from the point of the upper terminal to the common receiver 7the earth74 ,but this continuity may in strictness be interpreted in two ways3 it may be said that two pieces of metal in contact form a sufficiently continuous connection2 and it may be said1 on the other hand1 that most frequently this simple contact is no more than a break in consequence of oxidation and the interposition of foreign bodies4 ,the instruction of #ahbc1 without adopting the first interpretation1 does not appear to have sufficiently recommended the second1 which should exclusively regulate all construction of lightning rods4 ,no doubt it is possible1 by taking great care1 to join and bolt together two pieces of iron or copper closely enough to make a practically continuous conductor1 but when there are many joints we fear that evil might arise from the negligence of workmen1 and still more from the chemical alteration of the surfaces1 the deposition of foreign matter1 and the mechanical dislocation produced by time and repeated shocks4 ,hence1 the three following practical rules should always be observed3--#a4 ,to reduce as much as possible the number of the joints4 #b4 ,to make all the joints with hard solder1 and they should be upon surfaces of at least #aj centimetres 7#ci inches7 square1 and further strengthened by straps and bolts4 #c4 ,not to make the upper terminal so gradually pointed as usual4 ,the upper terminal of iron should be not less than #b centimetres 7#gh inch7 diameter1 the end should be filed down and a screw tapped #a centimetre 7#ci inch7 high and #a centimetre diameter1 and to this a cone of platinum #b centimetres diameter and #d centimetres 7#ae inch7 high1 and consequently having an angle at the point of #bh or #cj should be fitted1 screwed1 and carefully soldered4 ,in other respects the instructions of #ahbc should be followed2 no fact which leads to a modification of the general rules there proposed #a1 for the sectional area of the conductors2 #b1 for the method of fastening to buildings2 #c1 for the method of making the earth connection1 has since come to light4 ,the subject1 however1 is not exhausted1 there still remains the important and difficult question3 what is the circle of protection afforded by a well constructed lightning rod8 ,the opinion generally received at the end of the last century was that the circle of protection had a radius of twice the height of the terminal1 and the instruction of #ahbc adopted this opinion1 but with some restrictions as in the case of spires4 ,it is important to remember that these rules rest upon a more or less arbitrary basis1 and this is said not to condemn them1 but only to prevent there being attached to them a value which they do not possess4 ,more observations are required1 and it is only with reserve that these rules are admitted4 ,they are neither general nor absolute1 they depend upon a variety of circumstances1 and especially on the materials of the buildings4 ,for example1 the radius of the circle of protection1 which would be sufficient for a building having only wood tiles or slate on its upper portion1 would not be sufficient for a building in which the covering or the framing of the roof was of metal4 ,in the former case the active portion of the thunder cloud1 although further from the lightning rod than from the roof1 would exert a greater action on the rod1 whilst in the latter the action on the rod and on the roof would be almost equal at an equal distance4 ,a special note upon ships1 and another on the ,palais de l',exposition close the report4 ,,special ,,report ,,for ,,the ,,new ,,buildings ,,of ,,the ,,louvre1 #ah ,,december1 #ahed1 ,,by ,,the ,,same ,,committee4 ,referring to the subject of the earth connection the ,committee say2 in the earliest instructions1 it is said that the conductors should communicate with the water in a river1 a pond1 or wells1 or at least with moist earth4 ,this rule1 although quite correct in itself1 frequently leads to erroneous practice4 ,it is sometimes thought that lightning is extinguished by water1 as fire is2 and when water is scarce the conductors are plunged into a well-cemented cistern4 ,this is a most dangerous mistake2 the conductor should be in connection with the common receiver1 that is1 the great water-bearing strata 7nappes d'eau17 of much greater extent than the thunder cloud4 ,at other times where wells are possible but costly1 advantage is taken of the alternative allowed by the instructions4 ,instead of wells the conductors are put in connection with the earth1 without being careful to see that it preserves sufficient moisture in times of drought when storms are most to be expected1 and without being careful to see that the moist connection is sufficiently large4 ,they specially note this latter error1 as it appears to be still more common than the former4 ,they do not hesitate to say that recourse should never be had to this method of connection with the common receiver4 ,they recommend that in default of rivers or very large ponds1 the conductor should always be connected by large surfaces with the inexhaustible subterranean water-bearing strata4 ,secondly1 where these strata are at a moderate depth below the surface1 the ,committee consider it necessary to make use of a conductor with two branches1 the principal to descend to the subterranean water2 the secondary1 leaving it at the ground level1 is put in connection with the surface4 ,and for this reason2 after great droughts thunder clouds exert but a feeble influence upon a dry1 badly conducting soil4 ,all their energy is felt by the subterranean waters2 and the electricity will be carried by the principal branch4 ,on the other hand1 after a summer shower1 when the surface soil gets moist1 it is at once made a good conductor4 ,it is that which is affected by the thunder cloud3 while1 at the same time1 it screens the subterranean water from electrical influence4 ,in such a case it is indispensable that the surface of the ground should be in direct connection with the conductor2 and this the secondary branch supplies4 ,there is a final question how the conductors should be connected with the various metallic portions of the building4 ,the ridges are throughout of iron2 but the interior arrangements require that1 in some portions of the building1 there should be1 properly speaking1 only one floor1 whilst in other parts there are six4 ,each floor may be regarded as a great metallic network1 composed of several strong plate girders1 crossed by numerous joists analagous to rails1 while these are1 in their turn1 crossed by a multitude of smaller iron rods2 and the meshes of this network are filled with tiles4 ,in enquiring into the effect of a thunder storm upon those portions where there are six such floors one above the other1 it is easy to see that if the roof were a great continuous sheet of metal1 it would take up the whole electrical energy of the cloud1 at any rate1 as far as the floors underneath it are concerned4 ,in this case it would be amply sufficient if the covering were well connected with the lightning rods4 ,but in this case the roof is metallic1 only in a very small portion2 it may be said that the ridges only form a network with very large meshes1 and1 consequently1 is an insufficient shield1 through which the upper floor may still receive a considerable shock4 ,therefore the ,committee propose the following arrangements3--#ast4 ,the principal pieces of each floor should be put in connection with the conductor4 #bnd4 ,it is very desirable that all the joists of the upper floors should be connected together by a rod bolted1 and1 if possible1 soldered to each1 which rod should be connected with the conductors4 #crd4 ,it seems probable that1 in general1 the roof frames are in good connection with each other1 and1 consequently1 it would suffice if all the upper terminals are connected with them4 ,if1 however1 it happens either by changes of level in the gutters1 or from other causes that the connections become doubtful special iron connections must be made4 #dth4 ,the zinc gutters and ridges should be connected with the lightning rods4 ,,report on the points of upper terminals made by ,messrs4 ,delieul1 by a ,committee consisting of ,,mm4 ,,becquerel1 ,,babinet1 ,,duhamel1 ,,despretz1 ,,cagniard ,,de ,,latour1 ,,regnault1 ,,de ,,senarmont1 and ,,pouillet4 #eth ,march1 #ahee4 ,the committee examined the points presented by ,messrs4 ,delieul1 one of platinum1 made exactly as described in the report of the previous #ahth ,december2 the other1 a cone similar in form1 size1 and external appearance1 but rather less costly1 being made of a cap of platinum1 fixed with hard solder upon the conical end of the iron rod4 ,it was thought that this second arrangement would not practically be inferior to the other2 but it must be made by a skilful workman1 who knows how to insure that the solder should take to the whole of the surfaces brought together4 ,they see no objection to the substitution of palladium1 or gold or silver of a standard of #iej for the platinum4 ,but all these metals are costly2 few workmen know how to work in them1 or at least to employ that precision1 and take that minute care1 which are indispensable to success4 ,these reasons have raised again a proposition that was discussed in the former commission1 which consists in making the points of copper4 ,the copper point is #b centimetres 7#gh inch7 in diameter1 like the upper part of the iron rod1 to which it is screwed and brazed2 its length is about #bj centimetres 7#ghg inches71 and it terminates in a cone #c or #d centimetres 7#aa or #ae inches7 high4 ,they see no reason why this should not be used with almost the same confidence as the preceding forms4 ,if there is ground to fear that it may undergo changes from atmospheric influences1 this is counterbalanced by certain advantages4 #ast1 copper is with palladium1 gold1 and silver1 among the best conductors of heat and electricity2 and the point of the cone will be much less heated than the platinum point2 and #bnd1 the terminal1 with a copper point1 is much less expensive1 and can be made everywhere4 ,on the report being put to the vote ,m4 ,despretz could not approve the proposal to employ copper points1 fearing that the deposition of carbonate or some other badly conducting matter would diminish the efficacy of the lightning rod4 ,,instructions upon ,,lightning ,,rods for ,,powder ,,magazines1 by a ,committee consisting of ,,mm4 ,,becquerel1 ,,babinet1 ,,duhamel1 ,,fizeau1 ,,edm ,,becquerel1 ,,regnault1 le ,marchal ,,vaillant1 and ,,pouillet4 #adth ,january1 #ahfg4 ,after referring to some general principles1 and to the construction of lightning rods recommended in the reports of the earlier ,committees3 the ,committee recommend1 that the upper terminal including the copper point should be from #c to #e metres 7#i feet #aj inches to #af feet #e inches7 high2 that the junction of the conductor and the upper terminal1 and also the several joints of the conductor1 should be covered with solder1 and insist very strongly upon the necessity of communication with the nappe d'eau souterraine1 which they define as 8the water level in neighbouring wells which never dry up1 and which retain at least #ej centimetres 7#aifh inches7 in depth of water in the most unfavourable seasons40 ,the special arrangements to be adopted in setting up lightning rods for powder magazines are3 not to fix them on the building itself but outside the surrounding walls4 ,for each large sized magazine 7#bghi metres1 by #bj metres1 and #aa metres high1 equal to #ia feet #f inches by #fe feet #g inches1 and #cf feet high7 there should be three conductors--two near the ends of the long side of the enclosing wall most exposed to storms1 and the third in the middle of the opposite side4 ,the upper terminals should be only #e metres 7#af feet #e inches7 high1 and should be raised on a pier1 a mast1 or other support #ae metres 7#di feet #b inches7 high1 down which the conductor should be led to the ground4 ,there should be a circuit which the ,committee call circuit de ceinture carried entirely round the enclosing wall to which each conductor should be joined1 and a conductor should be carried from the most convenient point of this circuit to the underground water4 ,for middle sized magazines two terminals and supports1 and for small magazines one terminal and support will suffice2 but in all cases there should be a circuit de ceinture4 ,this need not be deep below the surface1 nor covered over2 it may even be in an open gutter1 but a conductor must be led from it to the underground water1 even if in order to do this it is necessary to carry the conductor several hundred metres or several kilometres4 ,it need not1 however1 be made of bars and carried all the way in a trench1 but it may be made of six wires #f or #g millimetres 7about #be inches7 in diameter1 and carried on posts like telegraph wires1 except that they need not be insulated4 ,,instructions by the ,committee consisting of ,,mm4 ,,alphand1 ,,belgrand1 ,,fizeau1 ,comte du ,,moncel1 ,,ed4 ,,becquerel1 ,,desains1 ,,ch4 ,,sainte ,,claire-,,deville1 ,,duc1 ,,ballu1 ,,magne1 ,,davioud1 ,,felix ,,lucas1 and ,r4 ,,francisque ,,michel1 appointed to inspect the ,,lightning ,,rods on the ,,municipal ,,buildings of ,,paris4 #bjth ,may1 #ahge4 ,the ,committee find that platinum tips are useless1 and recommend instead that the point of the terminal should be made of pure copper1 #ej centimetres 7#aig inches7 long1 and terminating in a cone1 forming an angle of #cj4 ,this should be scarfed1 pinned1 and soldered to the end of the terminal4 ,the terminal should be of wrought iron in one length1 and where possible galvanized2 but on no account painted4 ,the connection with the conductor should be by a piece fitted and bolted2 and1 lastly1 the whole joint should be well covered with solder4 ,the ,committee consider that on an ordinary building a terminal will effectively protect a cone1 having the point for its apex1 and a base whose radius is #age of its height4 ,but in practice the terminals may be much farther apart1 if there is a circuit des faites4 ,this is defined as a metallic conductor1 which extends without break over the ridges of all the buildings which it is intended to protect1 and which is joined by metallic contact to all the upper terminals and to the conductor1 and consequently to the underground water which alone forms the common reservoir4 ,all pieces of metal of any considerable size should be connected with the conductor4 ,if the conductor is made of iron bars1 they should be galvanized if possible1 and the joints should be fitted1 bolted1 and finally covered with solder4 ,if the bars cannot be galvanized1 they should be well painted4 ,the ,committee recommend the employment1 especially in the circuit des faites1 of an arrangement for compensating for the lengthening and shortening of the bars by the variations of temperature4 ,this is made by inserting in the circuit a curved band of copper which will yield to the movement of the rods4 ,if the conductor is made of galvanized iron wire rope1 each wire should be #be or #c millimetres 7#ji to #aa inch7 in diameter1 and there should be such a number of them that the sum of their sectional areas shall be equal to one-fifth more than that of a bar of iron #bj millimetres 7#gh inch7 square4 ,the rope should be all in one piece1 and the joints with the terminal and earth connection should be covered with solder4 ,the supports should not be insulated1 and there should be as few as possible of them4 ,at the underground end of the conductor should be fixed a large sheet or hollow cylinder of metal1 and this should be always1 even in the greatest droughts1 plunged at least #a metre 7#c feet #c inches7 into the subterranean water4 ,if from any cause this water cannot be reached1 the conductor may be joined to one of the main water-pipes of the city2 but if the conductor cannot be led either to the subterranean water or to a main water-pipe1 no lightning-rod should be erected4 ,it would do more harm than good4 ,in the case of buildings of any importance1 two or more conductors leading to the subterranean water should be employed4 ,it should be so arranged that the underground part and the earth connection may be easily inspected and cleaned from rust1 and the whole should be inspected and cleaned at least once a year1 at the end of the autumn4 ,the ,committee is of opinion that it would be better to put all the lightning-rod work in the hands of special workmen1 under the control of an agent appointed by the administration1 and not to trust it to the blacksmiths and locksmiths usually employed4 ,the ,committee lastly recommend that they should be permanently appointed1 and meet every year after the inspection1 to report and decide upon the steps to be taken to remedy any defects that may be discovered4 ,,report by the joint ,secretary 7,,francisque ,,michel7 of the ,lightning ,rod ,committee to the ,prefect of the ,department of the ,seine4 ,this report gives a detailed description of the state of the lightning rods attached to the public buildings of ,paris4 ,in most cases the upper terminals were of great length1 some of them as much as #i metres 7nearly #cj feet7 in height2 the conductors were in almost all cases of iron1 either in bars or wire rope2 the earth connections were of various kinds and extent4 ,the report frequently states that the points were blunted2 that the upper terminals and the conducting rods were deeply rusted2 that especially at the joints the conductors were seriously deficient2 and that the underground portion was greatly deteriorated by rust4 ,a description is given of an accident from lightning to the church of ,st4 ,sulpice2 but this building had no lightning rod4 ,in the case of the church of ,st4 ,clotilde there are five upper terminals1 two on the two spires1 the remaining three along the ridge of the main roof4 ,the building was amply protected as far as its length was concerned1 but the transept was not so thoroughly protected4 ,the five terminals were joined to a conductor which went round the building1 and was connected with the ground4 ,a second conductor led from one of the terminals to the ground1 where it terminated in a second pit4 ,the conductors were made of iron rods #ah millimetres 7#ga inch7 in diameter1 joined by collars and pinned and the whole covered with paint4 ,they terminated in distributors plunged in the underground water in walled pits4 ,they were supported by insulated collars4 ,the building has an iron roof4 ,the church had been struck by lightning at least four times since the lightning rods had been erected4 ,the first time1 twelve years ago1 the lightning struck the rod placed on the transept1 and carried away the platinum tip of the copper point4 ,since then the rod has received another discharge1 and the copper point is bent to the ,s4,w4 ,in ,january1 #ahgb or #ahgc1 the lightning struck the western tower1 and shattered one of the stones above one of the windows of the staircase4 8,one of the platinum tips is gone1 and many are blunted4 ,the conductivity of the conductor is very bad1 and the joints are very much damaged3 hence the accident to the tower4 ,the greater number of the glass insulators are broken1 or gone altogether40 ,in the case of the church of ,st4 ,eloi1 which had one terminal on the spire1 one conductor1 formed of iron wire rope #b centimetres 7#gh inch7 in diameter1 joined at #c metres 7#i feet #aj inches7 above the ground to an iron rod #be millimetres 7#ig inch7 in diameter1 which entered the ground and ended without branches in a pit filled with charcoal4 ,the soil was dry and calcareous4 ,the conductor was made up of many lengths of rope1 old pieces apparently having been used2 the joints were in bad condition1 and needed soldering4 ,the underground part was deeply rusted4 8,in ,september1 #ahgd1 lightning struck the spire1 twisted the conductor1 broke the terminal1 threw down the part above the cross1 and made great cracks in the apse40 ,during the building of the ,mairie of the #bjth ,arrondissement1 the lightning struck a fir-pole in the scaffolding4 ,it did not do any damage1 being carried away by the chain attached to the pole1 from which it took all the rust1 and being thence conducted by some pieces of iron roof framing lying on the ground4 ,there are several other accounts of accidents1 but they are mostly represented by the foregoing examples4 ,,instructions as to the application of ,,lightning ,,conductors for protection of ,,powder ,,magazines1 ,,etc4 ,issued with ,army ,circulars1 dated ,may #ast1 #ahge4 7,abstracted by ,prof4 ,t4 ,hayter ,lewis1 ,f4,s4,a47 #a4 ,the principles adopted by ,sir ,w4 ,s4 ,harris1 as shown in the ,appendices ,a and ,b1 to this paper1 still held to be sound4 #b4 ,the terminating plane of action of lightning is sometimes beneath the surface of earth1 which1 if moist1 forms good medium for diffusion of electricity4 #c4 ,dry soil is to be regarded as non-conducting matter4 #d4 ,therefore conductor to be taken into soil permanently damp4 #e-f4 ,underground magazines are usually in dry soil1 and should therefore be fitted with conductors as in the case of similar magazines above ground4 #h-i4 ,casemated batteries of modern construction1 with magazines in basement should have conductors on the parapet or terreplein from end to end of battery1 attached to vertical conductor into earth4 ,flagstaff should have conductor4 ,in large works there should be several points #e feet above top of building4 ,iron verandahs and railings are good conductors when with good earth connections4 #aj4 ,iron buildings are good conductors4 ,but if covered with asphalte1 concrete1 c41 rods or points must be provided projecting above asphalte1 c41 and with good earth connections4 ,iron shields should be connected with conductors4 #aa4 ,copper is recommended as best conductor2 it is not liable to corrosion1 and very durable4 #ab4 ,but if exposed to injury1 or likely to be stolen or corroded1 copper may be replaced by iron1 provision being made for its smaller conductivity--viz41 th that of copper4 #ac4 ,copper rods to be inch diameter2 copper tubes to be inch thick2 copper bands to be #a inch thick4 #ad4 ,if the conductor be of iron1 solid rods to be #a inch diameter2 solid bands to be #b inches wide inch4 #ae-af4 ,the fusing temperature of copper is #aiid ,faht42 whereas that of iron is #bghf ,faht4 ,so far there is a marked advantage over copper4 ,but it rusts easily1 and then the electrical resistance is immensely increased4 ,roughly speaking1 an equal conducting power may be obtained either in iron or copper for the same cost1 the number of iron conductors being greater in proportion to the less cost1 and the more conductors being the better4 #ag-ai4 ,expansion and contraction are to be carefully provided against2 e4g4 by suitable bends at intervals in long lines of horizontal conductors and by bearing collars1 allowing of slip in vertical lines4 #bj4 ,soldered or welded joints are desirable1 but not absolutely necessary4 #ba4 ,gives engravings of connections recommended by ,sir ,w4 ,s4 ,harris1 where soldered joints cannot be used1 and which fulfil the conditions specified in sections #ag-ai4 #bb4 ,soldered or welded joints to be used where discharge is possible with unsoldered joints1 and likely to ignite dust or inflammable substances near4 #bc4 ,iron may be connected by similar joints as for copper1 or by screw joints as for gas pipes4 ,no white lead to be used1 it being a bad conductor4 #bd4 ,iron flat bands may be connected by rivets or screws1 working in slots1 to provide for expansion1 each surface in contact being at least six times the sectional area of band4 #be4 ,copper bands to be similarly connected4 ,joints between different metals may be soldered1 screwed1 or rivetted1 the extent of surface in contact being regulated by the dimensions of the metal of the least conducting power4 ,access of moisture to surfaces in contact must be prevented1 on account of local galvanic action and decomposition4 #bf4 ,no precise limit can be fixed to protecting power of conductors4 ,in ,england the limit is usually assumed as being the radius of the height from ground4 ,it may be sufficiently correct for practical purposes1 but cannot always be relied upon4 #bg4 ,conductors do not attract lightning2 they only diminish the resistance due to the air4 ,even a change in the nature of the soil -over which a cloud passes may produce a discharge4 #bh4 ,one angle of a building may receive a discharge1 though another angle have a conductor4 ,so every prominent part of a building containing explosive material should have a conductor4 #bi4 ,in buildings of uniform height1 provide a solid rod #e feet above it at each end1 and at each #de feet in length2 if the conductor be of iron the top should be gilt4 #cj4 ,buildings not over #bj feet long to have one vertical conductor at end1 and a horizontal conductor on ridge4 #ca4 ,if #bj to #dj feet long to have one vertical conductor in centre1 and one along ridge1 as last4 #cb4 ,if #dj feet long to have two vertical conductors2 if #ajj feet long three conductors2 in both cases with conductor along ridge4 #cc4 ,similar principles to be adopted in larger and more complicated buildings4 #cd4 ,each prominent part should have a conductor4 ,the value of three or four points to terminals is not apparent unless the points are widely separated4 #ce4 ,conductors are to be connected horizontally1 e4g41 by ridge or eaves1 which1 when of metal1 should be invariably connected with conductor4 ,all metal surfaces whatever to be also so connected4 #cf4 ,sir ,w4 ,s4 ,harris considers the relative conductivity of the several metals as being--of lead #a1 tin #b1 iron #b1 zinc #d1 copper #ab4 ,so lead cannot be altogether depended on4 #cg4 ,avoid long lengths of horizontal conductors without earth contacts1 as the currents might leave the conductor1 and pass to earth1 causing danger4 ,avoid sharp angles4 #ch4 ,good earth connections most important4 ,conductors are to be led into springs or wells or earth permanently wet4 ,not into watertight tanks4 ,shingle1 dry sand1 or dry mould are not sufficient4 ,provide several earth connections in all large systems of conductors as a precaution4 #ci4 ,lead conductors into ground in trenches #ah inches deep4 ,not less than #cj feet of metal to be in contact with moist earth4 #dj4 ,lead a flow of water over trenches if possible1 e4g41 from rain water pipes4 #da4 ,trenches in rocky or dry soil to be #cj to #abj feet long1 so as to obtain all moisture possible4 #db4 ,connections in trenches may be of old iron1 forming continuous metallic surface1 the trenches to be filled with cinders or coal ashes4 ,water pipes form excellent earth connections1 but gas pipes are dangerous4 #dc-dd4 ,frequently inspect conductors1 especially as to joints connecting different metals and defects in iron from rust4 #de-df4 ,galvanize iron1 care being taken that the coating is good4 #dg4 ,great care to be taken in case of contact of zinc coating with other metals1 especially copper4 ,april #hth1 #ahge4 ,,fred4 ,e4 ,,chapman4 ,inspector ,general of ,fortifications4 ,,appendix ,a4--,,by ,,the ,,late ,,sir ,w4 ,,snow ,,harris1 ,f4,r4,s4 #a4 ,the earth's surface and clouds are the terminating surfaces of electric actions1 and buildings1 c41 are only points1 as it were1 of earth's surface in which the whole action vanishes4 #b4 ,electricity when confined to substances resisting its progress1 as air1 glass1 dry wood1 stones1 c41 exerts a terribly explosive power4 #c4 ,but when confined to bodies1 such as metals1 offering small resistance1 its violent expansion or disruptive action is greatly reduced or avoided altogether1 and becomes a continuous current comparatively quiescent4 ,but if body be small1 as wire1 it may be heated or fused4 ,resistance is so small that a shock has traversed copper wire at the rate of #egf1jjj miles a second2 resistance increases with length and diminishes with area of section of conductor4 #d4 ,so a building metallic in all its parts1 or a man in armour is safe4 #e4 ,so endeavour to bring buildings into the same passive or non-resisting state as if of metal4 #f4 ,so conducting channels of copper should be systematically applied to walls1 either in plates united in series one over another1 not less than #c inches wide and #a_/afth and th of an inch thick1 or of stout copper pipe not less than #c_/afths of an inch thick1 and #a to #b inches diameter1 fixed to building by braces or copper nails or clamps4 ,terminals to be solid metal rods1 projecting above to a moderate and convenient height4 ,earth connections to be by one or two branches1 leading out about a foot below ground--if possible into moist ground1 but if dry1 use old iron or other metallic chains so as to expose a large metallic surface4 #g4 ,all metals in roof1 c41 of building to be connected with main conductors2 any prominent chimney to have a pointed conductor taken along it to metals of roof4 #h4 ,an electrical discharge never leaves a perfect conductor to pass to a very bad one1 so the apprehension of lateral discharge is absurd4 ,furious discharges have fallen on the conductors to the masts of ,h4,m4 ships1 and passed through copper bolts in bottom without injury even to persons leaning against the conductors4 #i4 ,metallic bodies have no specific attraction for electricity more than wood or stone have2 all matter is indifferent so far as regards a specific attraction4 ,lightning falls indiscriminately upon trees1 rocks and buildings1 whether with metals about them or not2 e4g41 at ,plymouth ,dockyard in ,may1 #ahda1 a granite chimney1 #abj feet high1 without any metal in it1 was struck1 and yet it was within #cjj feet of a clock-tower of equal height1 having metal weathercock1 a dome covered with metal and large conductor along it to ground4 ,the damage ceased where the chimney passed through a massive metallic roof1 having a conductor from it to the ground4 ,here the lightning fell on a building1 which1 according to the popular idea1 held no 8invitation0 in preference to a structure which did hold such 8invitation40 #aj4 ,if efficient conductors provide free and uninterrupted course for electrical discharge1 it will follow that course without danger to general structure2 if not1 then this irresistible agency will find a course for itself and shake all imperfect conducting matter in pieces in doing so4 ,the great object is to provide a line or lines of small resistance in given directions1 less than the resistance in any other line of the building4 ,the conductor no more attracts lightning than a gutter or water pipe attracts a flow of water4 #aa4 ,it follows that a magazine if of metal would be safer than if built in the usual way4 ,metallic gutters and ridges1 with continuous metallic communications to earth1 are unobjectionable4 ,,note4--,it is as wrong to isolate conductors from buildings by glass or resin1 as it would be to place rain water pipes #aj feet from the building from which they should carry off the water4 ,an instance is given of an iron conductor which was placed #aj feet from a house1 the latter being1 notwithstanding1 struck at the point nearest to the conductor1 which was untouched4 #ab4 ,pointed terminations tend to break the force of lightning when it falls on them4 ,before explosion a large amount of discharge passes off through pointed conductors4 ,pointed conductors should be solid copper rods1 about inch diameter1 and a foot long1 united by brazing to the conducting tube4 ,it is not necessary to gild the points1 or form them of platinum4 ,sometimes even1 this would be detrimental1 as platinum has only half the conducting power of copper4 ,the oxidations of the surface of conductor is of little moment2 and in case of copper very trifling4 ,in any case the conducting surface is better than the bad--or non-conducting air4 ,the electric telegraph wires work well1 though enclosed by gutta percha or other non-conducting matter4 ,it is sufficient if the terminal solid rod be even roughly pointed4 ,but even a ball1 a foot diameter1 would be a point as opposed to #a1jjj acres of charged clouds4 ,,note4--,experience contradicts the idea that the conductor protects a certain area4 ,the foremast of a ship has been struck1 though the mainmast has been protected by conductor4 #ac4 ,copper linings to doors and windows of magazines1 are not objectionable1 but useless for keeping out lightning4 ,they should be connected with the general system of conductors4 ,,appendix ,b4--,,as ,,to ,,solid ,,or ,,hollow ,,conductors4 ,,by ,,sir ,w4 ,,snow ,,harris1 ,f4,r4,s4 #a4 ,a given quantity of electricity melts the same quantity of metal1 whether in a solid or hollow form4 ,so far it is immaterial which form the conductor has4 ,but supposing the mass of metal to be so large that the heating effect may be neglected4 ,it is proved that the greater the surface1 the less is its intensity or power at any point1 the intensity approaching the second power or square of the surface inversely4 ,it is important to give the charge free room of expansion by increasing the surface of conductor1 so as to reduce the mechanical activity of shock to the least possible4 ,rectangular flat bars may be employed4 #b4 ,a rain water pipe communicating with main conductor1 should have earth connection4 ,all imperfect substances1 as masonry1 and ship masts1 transmit a certain portion of electricity without explosive action4 ,one great use of the conductor is to relieve the wood or masonry of the quantity it cannot discharge without explosion4 #c4 ,conductors of small iron rod or wire are very objectionable4 ,they commonly rust at the joints1 and have fallen to pieces1 and often been knocked to pieces by lightning4 ,iron may1 certainly1 be employed with advantage1 but should be galvanized4 ,zinc is an even better conductor than iron2 and being spread over the surface is not open to the objection of making a conductor of two metals of unequal conducting power4 ,a good and efficient conductor might be formed of galvanized iron4 ,it should be of wrought iron1 galvanized1 of #b inches diameter1 with screwed joints of extra thickness4 ,copper tubing is1 however1 always to be preferred4 #d4 ,in dry or rocky soil1 complete the conductor by leading old iron chains out from the walls in several directions1 or by leading a flow of water over them4 ,fortunately a thunder storm is usually attended by heavy rains4 ,the iron chains should extend #cj to #ej feet1 and be a foot or #ah inches under ground4 ,the termination in a large surface of moist earth would be preferable to that in a well1 as the action is a superficial one of expansion in all directions4 ,in the tin leaf coatings of the electrical jar1 the charge is not influenced by the thickness of metal4 ,w4 ,,snow ,,harris4 ,,report ,,on ,,the ,,destruction ,,by ,,lightning ,,of ,a ,,gunpowder ,,store ,,at ,,bruntcliffe1 ,,yorkshire4 ,,by ,,major ,y4 ,d4 ,,majendie1 ,r4,a4 7,abstracted by ,g4 ,j4 ,symons1 ,f4,r4,s47 ,the ,gunpowder exploded at #d4cj p4m4 on ,august #fth1 #ahgh1 during the greatest intensity of a violent thunderstorm4 ,the building1 was brick1 with brick arched roof1 length #i feet1 width #e feet1 height #f feet 7internal dimensions74 ,the store had a uniform thickness of three bricks1 and was furnished at the one end with an iron door1 at the other end with a lightning conductor4 ,the conductor consisted of a copper wire rope1 #aj gauge copper wire1 the rope being #g_/af inch thick1 having four points at the top 7one large one in the centre1 and three smaller ones round it71 it extended to about #ac feet above the top of the building1 and about the same length was carried into the ground and terminated in a drain4 ,the conductor had been erected in #ahgf1 by ,mr4 ,john ,bisby1 of ,leeds1 and was fixed to a pole distant about #b inches from the end of the building opposite to that in which the iron door was fixed1 it was not connected with the iron door in any way4 ,no one was near the store when the powder exploded1 and it seems probable that the earth connection of the conductor was bad1 that the mass of iron in the door offered at least an equally good path--and that the gunpowder was ignited by a flash passing between1 the two imperfect conductors4 ,illustration3 ,view and ,plan of ,bruntcliffe ,gunpowder ,store 8,the only structural damage effected was produced by the impingement of bricks1 which striking with great force1 had in a few instances1 partially penetrated or displaced brick work in the dwelling-houses and buildings1 and a portion of the iron of an iron church was broken by a piece of projected dbris4 ,a brick was driven through a window in one of the houses at three hundred yards1 and broke a bedstead4 ,as far as ,i have been able to discover no other structural injury was occasioned40 ,this accident appears to suggest several conclusions3-- 8,in the first place it appears to me to afford a striking confirmation of the principle which has been repeatedly and emphatically enunciated by ,sir ,william ,snow ,harris and other authorities on the subject of lightning conductors1 that in order to secure an efficient protection for a given building1 all the metal of the building1 and as far as possible the whole of the structure itself1 should be brought into actual connection with the system of conduction2 in other words1 that the general conducting power of the mass of the edifice should be completed1 and all attractive and prominent parts allied in one protective combination1 so as to 8bring the whole0 7as it has been expressed by ,sir ,william ,snow ,harris7 8as nearly as may be into that passive or non-resisting state which it would assume1 supposing the whole were a mass of metal40 ,in the present case1 assuming the conductor itself to have been efficient1 a point which there seems no sufficient reason for doubting1 the system of conduction was obviously defective4 ,not only was the whole length of the building left unprotected1 the conductor having been on a pole at one end1 and carefully insulated from the building1 but the iron door which was at the opposite end1 was absolutely unconnected therewith1 and was not itself supplied with any earth connection40 8,it appears clear1 therefore1 that even what may be deemed per se an efficient lightning conductor1 i4e4 a conductor1 which considered alone1 offers a path of little or no resistance even to a powerful electric current1 does not afford a reliable protection to a building unless it be scientifically applied1 and with due regard to those principles upon which the more eminent authorities on electrical science are agreed4 ,to a disregard of these principles1 especially in respect of the iron door being left out of the system of conduction1 and unconnected therewith1 ,i believe the present accident may be attributed40 ,,reports ,,of ,,committees ,,on ,,the ,,powder ,,magazines ,,at ,,purfleet4 7,phil4 ,trans41 #aggc1 p4 #db1 and #aggh1 ,part ,i41 p4 #bcb47 7,abstracted by ,prof4 ,w4 ,g4 ,adams1 ,f4,r4,s47 ,report of a ,committee consisting of the ,hon4 ,henry ,cavendish1 ,dr4 ,watson1 ,dr4 ,franklin1 ,mr4 ,j4 ,robertson1 ,mr4 ,wilson1 and ,mr4 ,delaval1 appointed by the ,royal ,society1 8to consider of a method for securing the powder magazine at ,purfleet40 ,a powder mill at ,brescia having blown up in consequence of being struck by lightning1 the ,board of ,ordnance applied to ,mr4 ,b4 ,wilson to know in what way the powder magazine could be protected4 ,he recommended that a blunt conductor should be employed1 whereas ,dr4 ,franklin recommended a pointed conductor4 ,the ,committee met and ,dr4 ,franklin read a paper on the subject1 and the report of the ,committee was in conformity with ,dr4 ,franklin's views4 ,the ,committee went to ,purfleet and examined the buildings4 ,they found that the barrels of powder1 when the magazines were full1 lay piled on each other up to the spring of the arches2 on each barrel were four copper hoops1 which with vertical iron bars formed broken conductors within the building4 ,these iron bars were ordered to be removed4 ,the ,committee advised that at each end of each magazine a well should be dug in or through the chalk1 so deep as to have in it at least four feet of standing water4 ,from the bottom of this water should arise a piece of leaden pipe to or near to the surface of the ground1 where it should be strongly joined to the end of an upright iron bar1 an inch and a half in diameter1 fastened to the wall by leaden straps1 and extending ten feet above the ridge of the building1 tapering from the ridge upwards to a sharp point1 the upper twelve inches of copper1 the iron to be painted4 ,lead was mentioned for the underground part as less liable to rust1 in the form of a pipe as giving greater stiffness for the substance1 and iron for the part above ground as stronger1 and less likely to be cut away4 ,the pieces of which the bar may be composed should be screwed strongly into each other by a close joint with a thin plate of lead between the shoulders4 ,each rod in passing above the ridge should be strongly and closely connected by iron or lead1 or both1 with the leaden coping of the roof1 so making metallic communication between the two bars of each building4 ,it was also advised that two wells be dug within twelve feet of the doors1 one to the north of the north building and the other to the south of the south building1 and that metallic communications be made between the water in them and the leaden coping of the roof4 ,the ,board house stood #aej yards from the magazines1 on elevated ground1 and was a 8lofty building with a pointed hip-roof1 the copings of lead down to the gutters1 from which leaden pipes descend at each end of the building into the water of wells of forty feet deep1 for the purpose of conveying water forced up by engines to a cistern in the roof40 ,as to the ,board-house1 they thought it already well furnished with conductors by the several leaden communications above-mentioned from the point of the roof down into the water1 and that by its height and proximity it may be some security to the building below it2 they therefore proposed no other conductor for that building1 and only advised erecting a pointed iron rod on the summit1 similar to those before described and communicating with those conductors4 ,mr4 ,wilson dissented from that part of the ,report which recommended that each conductor should be pointed1 because1 he says1 8by points we solicit the lightning1 and may promote the mischief by drawing the charges from charged clouds1 which would not discharge at all on the building if there were no points on the conductors40 ,by experiments made and appealed to at the ,committee the difference in the effects between pointed and blunted conductors is as twelve to one4 ,mr4 ,wilson states that1 8,a thunder cloud1 therefore1 if it acted at #abjj yards distance upon a point1 would require a blunted end to be brought within the distance of #ajj yards1 and beyond those limits would pass over it without affecting it at all40 ,he also says1 8,the longer the conductors are above the building1 the more danger is to be apprehended from them4 ,i have always considered pointed conductors as being unsafe by their great readiness to collect the lightning in too powerful a manner40 ,mr4 ,wilson adds an account of an accident to ,st4 ,paul's ,church1 and some curious reasoning on it in support of his own views4 7,see ,phil4 ,trans4 #aggc1 p4 #ei-fa47 99 99 99 99 99 ,on the #aeth of ,may1 #aggg1 the ,board ,house at ,purfleet was struck by lightning1 and some of the brickwork damaged 7,see ,phil4 ,tran41 #aggh1 ,pt4 ,i41 p4 #bcb74 ,about #f p4m41 after heavy rain through the day1 a heavy cloud hung over the house for some time1 and ,mr4 ,nickson1 who watched it from the house and gives the account1 says he suspected that some of the conductors might find employment from it4 ,he had not been long at the window before a violent flash of lightning and clap of thunder came together4 ,the lightning struck one of the iron cramps that hold the coping1 and made a dent in the lead of the cramp and the stone adjoining it1 throwing some stone down and slightly disturbing about a cubic foot of brickwork at ,a4 ,the iron cramp was situated over a plate of lead1 and the ends of it1 inserted in the stone1 came within #g inches of that plate1 which communicated with the gutter1 and served as a fillet to it2 this gutter was part of the main conductor of the building4 ,the lightning struck through the stone1 c41 to the corner of the plate1 fusing a very small portion of it4 ,from this point no farther effect of the lightning could be traced4 ,at the distance of seven feet and a-half from the place struck1 a large leaden pipe went down from the gutter to a cistern of water in the yard4 ,it is remarkable that the surface of one of the hip-rafters1 four inches and a-half in diameter1 covered with lead 7communicating with the gutter71 and reaching within twenty-eight inches of the place struck1 seems not to have been at all affected4 ,the distance from the point of the conductor on the house to the part struck was forty-six feet4 ,illustration3 ,view of ,board ,house1 at ,purfleet ,a fresh ,committee of the ,royal ,society1 consisting of ,mr4 ,henly1 ,mr4 ,lane1 ,mr4 ,nairne1 and ,mr4 ,planta1 recommended a channel to be made from cramp to cramp round the parapet1 filled with lead1 and connected in four places with the main conductor on the roof of the building4 ,mr4 ,wilson again dissented from their report1 and attributed the hanging of a heavy cloud over the house 7it being calm at the time7 to the presence of the pointed lightning conductor4 ,an account of ,mr4 ,wilson's elaborate series of experiments at the ,pantheon on a long cylinder to illustrate the effects of pointed and rounded conductors occupies seventy pages of the ,philosophical ,transactions2 and another ,committee of the ,royal ,society1 consisting of ,sir ,john ,pringle1 ,dr4 ,watson1 ,henry ,cavendish1 ,w4 ,henly1 ,bishop ,horsley1 ,t4 ,lane1 ,lord ,mahon1 ,e4 ,nairne1 and ,dr4 ,priestley1 report in favour of having additional conductors ten feet high1 with copper eighteen inches long1 finely tapered and acutely pointed placed upon the magazines4 ,they conclude that 8elevated rods are preferable to low conductors terminated in rounded ends1 knobs1 or balls of metal10 conceiving that1 the experiments and reasons1 made and alleged to the contrary by ,mr4 ,wilson1 are inconclusive4 ,mr4 ,wilson's objections are again urged by ,dr4 ,musgrave1 but called in question by ,mr4 ,nairne 7see ,phil4 ,trans41 #aggh1 ,pt4 #b1 p4 #hbc71 who makes a series of experiments to illustrate the advantage of pointed conductors4 ,both ,mr4 ,wilson's and ,mr4 ,nairne's experiments agree in showing that 8pointed conductors draw off the electricity from a cloud at a much greater distance than those which are blunted40 ,mr4 ,wilson objecting that this draws the charged cloud from a greater distance2 and ,mr4 ,nairne concluding that 8a charged body is exhausted of more of the fluid by a pointed than by a blunted conductor10 and so is not likely to cause so much damage since it discharges itself more gradually4 ,,experiments ,,and ,,observations ,,on ,,electricity4 ,,by ,,benjamin ,,franklin4 ,fifth edition4 ,london1 #aggd4 7,abstracted by ,prof4 ,t4 ,hayter ,lewis1 ,f4,s4,a47 ,the author shows that pointed bodies draw off electricity much more effectually than blunt ones4 ,when the land is hot1 8the lower air is rarified and rises2 the cooler1 denser air above1 descends40 ,the clouds meet over the heated place1 8and if some are electrified and others not1 lightning and thunder succeed1 and showers fall40 8,as electrified clouds pass over a country1 high hills and trees1 towers1 spires1 masts1 chimneys1 c41 as so many points1 draw the electrical fire and the whole cloud discharges there40 ,therefore it is dangerous to take shelter under a tree4 ,it is safer to be in the open fields1 especially if the clothes are wet4 ,metals are fused1 possibly without heat2 the lightning creating a violent repulsion of the particles of the metal it passes through4 ,he afterwards admits this opinion to be erroneous4 ,describes experiments with sharp-pointed metallic bodies1 and says3 8,may not the knowledge of this power of points be of use to mankind in preserving houses1 churches1 ships1 c41 from the stroke of lightning1 by fixing on their highest parts upright rods of iron1 made sharp as a needle1 and gilt1 to prevent rusting2 and from the feet of these rods lead iron wire down the outside of the building into the ground2 or down one of the shrouds of a ship and her side till it reaches the water40 8,would not pointed rods probably draw the electrical fire silently out of a cloud before it came nigh enough to strike1 and thereby secure us from that most sudden and terrible mischief80 ,he mentions the case of the topmast heads of a ship being struck1 but having flames upon them like very large torches before the stroke4 ,he thinks that if there had been a good wire conductor from the heads to the sea there would have been no stroke or damage4 ,he records the experiments on the #ajth of ,may1 #ageb1 at ,marly1 of ,m4 ,d',alibard1 who placed upon an electrical body a pointed bar of iron #dj feet high4 ,in a thunder storm sparks of fire were attracted from it4 ,again1 at ,paris1 on the #ahth of ,may1 with the same result1 by ,m4 de ,lor1 with a bar of iron #ii feet high upon a cake of resin #c inches thick and #b feet square4 ,similarly in ,london in ,july1 #ageb1 by ,mr4 ,canton4 ,he refers to other experiments4 ,he experimented in #ageb with a kite of thin silk 7as being able to bear the wet71 having a very sharp-pointed wire fixed to its top1 above which it rose about a foot4 ,the kite was raised by twine1 the part in the hand being made of silk and kept quite dry4 ,the pointed wire will draw the electric fire from thunder clouds1 and when the rain has wet 7sic7 the kite and twine1 so that it conducts the electric fire freely1 they will be electrified1 and the electric fire will stream out plentifully on the approach of the knuckle4 8,spirits may be kindled1 c41 as with a rubbed glass or tube1 and thereby the sameness of the electric matter with that of the lightning be completely demonstrated40 ,september1 #ageb4 ,he erected 8an iron rod to draw the lightning into his house in order to experiment on it40 ,after many experiments1 he concluded that 8the clouds of a thunderstorm are most commonly in a negative state of electricity1 but sometimes in a positive state40 ,the latter1 he believed1 rare4 8,so that1 for the most part1 in thunderstrokes1 it is the earth that strikes into the clouds1 and not the clouds into the earth40 ,in the contrary 7rare7 case the cloud was1 8,i conjecture1 compressed by the driving winds or some other means1 so that part of what it had absorbed was forced out1 and formed an electric atmosphere round it in its denser state1 so communicated positive electricity to my rod40 8,the electric fluid1 moving to restore the equilibrium between the cloud and the earth1 takes1 in its way1 all the conductors it can find 7v4 page #acb of ,franklin's book7--as metals1 damp walls1 moist wood1 c4--and will go considerably out of a direct course for the sake of the assistance of a good conductor40 8,explosions only happen when the conductors cannot discharge it as fast as they receive it1 by reason of their being incomplete1 disunited1 or too small1 or not of the best materials for conducting40 ,he supposes that a wire inch diameter will conduct the electricity of any one stroke of lightning ever known4 ,iron is the best material1 as least liable to fuse4 8,pointed rods erected on buildings and communicating with moist earth would either prevent a stroke1 or1 if not prevented1 would conduct it so that the building should suffer no damage4 ,he gives instances of a small wire acting as conductor and saving the building1 though the wire1 being too small1 was utterly destroyed4 ,his theory as to the crooked course of lightning is as follows3 8,who knows but that there may be1 as the ancients thought1 a region of this fire 7electric7 above our atmosphere1 prevented by our air and its own too great distance of attraction from joining our earth4 ,yet some of it be low enough to attach itself to our highest clouds10 which thence become electrified1 c4 8,i am still at a loss about the manner in which clouds become charged with electricity1 no hypothesis ,i have yet formed perfectly satisfying me40 ,he describes how he and others have been struck down by electric shocks without feeling pain or sustaining permanent injury4 ,for protecting powder magazines1 erect a mast not far from it1 and #ae or #bj feet above the top of it1 with a thick iron rod fastened to it1 reaching down till it comes to water4 8,in buildings the rod may be fastened to the walls1 chimneys1 c41 with staples of iron4 ,the lightning will not leave the rod 7a good conductor7 to pass into the wall 7a bad conductor7 through these staples4 ,it would rather1 if anywhere in the wall1 pass out of it into the rod to get more readily into the earth40 ,if the building be very extensive1 two or more rods may be placed at different parts for greater security4 ,it is well not to sit near the chimney1 or gilt objects1 during a thunderstorm4 ,,an ,,essay ,,on ,,the ,,cause ,,of ,,lightning1 and the manner by which the thunder clouds become possessed of their electricity1 deduced from known facts and properties of that matter1 to which are added plain directions for constructing and erecting safe conductors4 ,by ,,john ,,simmons4 #hvo4 #agge4 7,abstracted by ,prof4 ,t4 ,hayter ,lewis1 ,f4,s4,a47 8,as on the earth the operation necessary for the excitation and collection of the electric fluid is attrition40 444 8,so we may rationally conclude that attrition is the means of excitation and collection of electric matter in the clouds as well as on the earth40 ,by metallic conductors buildings may be preserved from the effects of lightning ,electricity ascends from the earth to the clouds by means of moist air4 8,a conductor is a continuation of metal from a certain height above the highest part of a building to moist earth or water0 444 8for easy and safe passage of lightning40 ,metal is the best of all conductors4 ,the author quotes from ,franklin 8buildings that have their roofs covered with lead and spouts of lead continued from roof into ground to carry off the water1 are never hurt by lightning when it falls on such a building40 ,the conductor may be made of any metal1 and flat or round4 ,but nowhere less than inch diameter except at terminal4 ,but iron rusts1 so copper or lead should be used4 ,lead is best1 used in strips #d inches wide and th inch thick4 ,good earth contact required in moist earth 7going therein at least #e feet7 or water4 ,the several lengths of the conductor must be well in contact by being screwed1 if of iron2 soldered1 if of lead4 ,the upper terminal to be iron or copper rod #i or #aj feet long1 inch diameter1 and #b to #e feet above top of highest chimney or other part of building4 ,it should be pointed as this attracts electricity better4 ,lead roofs to be connected with conductor4 7,examples given of house and ship struck47 ,no building or object is known to have been struck by lightning within #ej feet of a proper conductor4 ,but a tree has been shivered within #eb feet1 so we may conclude that protecting influence extends to #ej feet horizontally in every direction from the point of conductor4 ,in gunpowder stores1 conductors are not to be fixed to the buildings1 but at 7say7 #ab feet away1 fastened to a standard1 the top being as high above the building as it can be conveniently4 ,no metal on sides or roof of the building is to be exposed to the lightning so as to attract it4 ,a ,,treatise on ,,atmospheric ,,electricity4 ,,by ,,john ,,murray4 #ahcj4 7,abstracted by ,prof4 ,w4 ,g4 ,adams1 ,f4,r4,s47 ,in ,chapter ,v41 on lightning identified with electricity1 the author speaks of fire-balls and the ,aurora ,borealis1 and ascribes the formation of shooting stars to electrical action4 ,he does not believe they come from distant space into our atmosphere1 but regards them as concretions formed by a flash of lightning darting through gaseous media and atmospheric air expanded by heat1 carrying metallic dust and earthy particles ejected from volcanoes1 or carried up by evaporation or other causes1 and diffused over an immense surface in the upper regions of the air4 8,the lightning carries1 like a ploughshare1 the accumulated matter in its progress1 and1 by the powerful electrical attraction thus excited1 these particles will be drawn into the vortex of the lightning instantaneously2 for1 the lightning finally encountering an electricity of an opposite kind1 an explosion ensues1 and the collected mass is instantaneously fused and agglutinated1 while the meteorite thus formed tumbles to the ground4444 ,we therefore do not see the necessity of considering meteoric stones extra atmospheric40 ,in this way ,john ,murray goes on page after page1 but the above will probably be sufficient notice of his work4 ,the following are the conditions he lays down for a good conductor3-- #a4 ,a finely pointed summit to offer an unresisting entrance4 #b4 ,a sufficient length to anticipate1 as it were1 the descending electricity1 and receive it on its summit before it could reach any part of the building4 #c4 ,a superior conducting power in the material of the rod to facilitate its passage to the earth4 #d4 ,a sufficient thickness to prevent its fusion1 which1 however1 will greatly depend on the resistance it has encountered in entering the conductor4 ,and1 finally #e4 ,a safe conduction to a well or moist surface below ground4 ,he says3 8,let the wires below ground in contact with moisture pass through a cylinder of zinc before they diverge to form the root1 the copper wires will in this case always remain free from any oxidation40 ,,harris',s ,,lightning ,,conductors4 ,,report to the ,committee upon ,,mr4 ,,snow ,,harris's and other ,,lightning ,,conductors4 7,february #aath1 #ahdj4 ,parliamentary ,paper4 ,fcap4 folio74 7,abstracted by ,professor ,w4 ,e4 ,ayrton74 ,instances are given of ships not provided with lightning conductors being struck and damaged1 whilst others lying near1 and provided with conductors1 were not injured4 ,the question of lightning conductors attracting lightning considered1 and evidence shown to the contrary4 ,lateral discharge from a lightning conductor considered4 ,evidence against it1 if only the conductor were continuous and of sufficient size4 ,faraday considered that a man leaning against one of ,harris's conductors when the electricity descended would not be hurt4 ,proposition to place a globe of glass on the head of the mast in place of a lightning conductor considered1 and the conclusion arrived at that it would do harm4 ,wheatstone stated that 8in the ,report of the ,committee of the ,academy of ,sciences of ,paris1 appointed to investigate the utility of lightning conductors1 there is no instance on record of an iron rod of inch in diameter being fused or even made red-hot by a flash40 ,mechanical objections to lightning conductors on ships considered and discussed4 ,decided that the application of ,mr4 ,harris's conductor tended rather to strengthen than weaken the mast and spars4 ,then follows a large number of letters1 giving accounts of accidents from lightning to ships1 c4 ,decision arrived at that on the whole ,mr4 ,harris's conductor is the best of those examined4 ,,the ,,difference ,,between ,,leyden ,,discharges ,,and ,,lightning ,,flashes4 ,,by ,c4 ,v4 ,,walker1 ,hon4 ,sec4 ,lon4 ,electrical ,soc4 ,london4 #ahdb4 7,abstracted by ,prof4 ,t4 ,hayter ,lewis1 ,f4,s4,a47 ,the author alludes to the experiments of ,franklin1 c4 ,the distance to the lower surface of clouds1 observed by ,le ,gentil and others1 shows an average of #ajjj to #bjjj feet1 whereas the greatest length of spark with a large machine is #c to #d feet4 ,the inductive action bears some inverse ratio to the distance4 ,leaves of trees have a remarkable property of silently drawing off electricity4 ,he gives the particulars of a large number of experiments1 with arguments thereon1 to prove the theory of the difference between ,leyden discharges and lightning4 ,quotes examples of lightning on conductors and buildings to show that the conductor takes part only of the charge1 the remainder taking other paths4 ,contiguous semi-insulated bodies must not be left unconnected with the lightning rod4 ,he quotes1 with approval1 the advice of ,faraday1 viz41 to tie together with a metallic connection all contiguous readily-conducting bodies4 ,cites numerous other opinions to the same effect1 viz41 that all metallic parts of a building should be connected with the conductor4 ,he sums up by stating 8that the ,leyden charge differs considerably not so much in nature as in degree from that of the cloud1 inasmuch as the proximity of the coatings in the one case is infinitely small compared with the distance in the other10 c4 ,he expresses great confidence in ,sir ,w4 ,s4 ,harris's system for protecting ships4 ,,the ,,effect ,,of ,a ,,lightning ,,flash ,,on ,,the ,,steeple ,,of ,,brixton ,,church1 ,,and ,,observations ,,on ,,lightning ,,conductors ,,generally4 ,,by ,c4 ,v4 ,,walker4 ,london4 #ahdb4 7,abstracted by ,prof4 ,t4 ,hayter ,lewis1 ,f4,s4,a47 ,the author refers to ,faraday's experiments1 as shewing instances of lateral discharge1 and says1 8unless precautions are taken to prevent its proceeding from a lightning conductor1 that instrument literally invites the enemy within doors40 ,he gives detail of the accident at ,brixton1 there being no lightning conductor4 ,the stroke did much damage to the steeple and then passed off harmlessly by the metal gutters and rain-water pipes4 ,one side of the steeple was drenched with wet and carried off part of the stroke4 ,he quotes examples of the apparently protective action of high trees4 ,lofty trees near lofty buildings would materially mitigate1 if not prevent1 the violence of the stroke4 ,the accident at ,brixton shows that the lightning takes not simply the shortest1 but1 in addition1 the largest path4 ,had the steeple been provided with a lightning conductor outside1 passing near the clock face or the bells1 or water pipe1 it is more than probable that a flash would pass from it to these vicinal conductors4 ,if outside the tower the danger would be greater4 ,he recommends that the metal cross on the steeple be replaced by a stone one1 and that the present iron rain water-pipes be connected by copper rods or plates1 which are also to be connected with the lead work of roof4 ,the bells are also to be connected with each other and with the conductor4 ,every bolt-clamp or other piece of metal within 8striking distance0 of the conductor1 unless in direct communication with it1 is liable to cause lateral discharge4 ,the odour developed by lightning was1 at ,brixton1 decidedly sulphurous1 as a piece of stone which was shattered by the stroke retained the odour of sulphur distinctly for several hours4 ,,on ,,the ,,nature ,,of ,,thunderstorms2 ,,and ,,on ,,the ,,means ,,of ,,protecting ,,buildings ,,and ,,shipping ,,against ,,the ,,destructive ,,effects ,,of ,,lightning4 ,,by ,w4 ,,snow ,,harris1 ,f4,r4,s4 #ahdc4 7,abstracted by ,prof4 ,ayrton47 ,the backstroke may do injury1 that is1 a person may be killed in consequence of a flash of lightning passing between the clouds and the earth at some distance from the person4 ,in the ,phil4 ,trans4 for #aghg1 ,mr4 ,brydone writes to the ,president of the ,royal ,society1 and mentions the case of two men riding in two carts1 the front one drawn by two horses1 these horses and the man driving them were killed21 the man on the hinder cart and a shepherd at a distance1 saw the occurrence and heard a report but observed no lightning4 ,a metallic screen appears to protect the interior from the action of a current1 as well as from static induction4 ,dr4 ,franklin found he could not destroy a wet rat by artificial electricity1 although he could a dry one4 ,the first lightning conductor was erected in ,england at ,payneshill1 by ,dr4 ,watson1 in #agfb4 ,the lightning conductor should expose a large surface1 and should be united with all the great masses of metal in its vicinity4 ,for stationary elevations the conductor should consist of solid or tubular rods or flat plates of metal4 ,we must consider the mechanical action the lightning may produce on the conductor1 as well as any possible heating action4 ,sir ,w4 ,snow ,harris mentions that there were no signs of fusion in the fragments of the linked brass rod1 at ,charles ,church1 ,plymouth1 torn to pieces in #ahbd1 or in the small pieces of the conductor at the ,hotel des ,invalides1 at ,paris1 consisting of a strand of twenty iron wires1 and which was smashed in #ahci4 ,he says the benefical effect of superficial conductors appears to depend on the removal of the electrical particles further out of the sphere of each other's influences4 8,thus we find10 says ,sir ,w4 ,snow ,harris1 8in a variety of cases of damage by lightning that the passing charge1 in striking on large expanded sheets of metal has become comparatively tranquil1 and has been traced no further1 whilst in striking on large masses of metal exposing but a small surface1 it has assumed an intensely active state40 ,he goes on to state that the resistance of the conductor must be kept as low as possible1 and as neither the resistance nor the heat developed is increased by rolling the wire out into a flat surface1 he argues that 8there is1 consequently1 no disadvantage in giving a lightning rod as much superficial capacity as possible1 as regards conducting power1 whilst1 on the contrary1 the diminished intensity attendant on it is very advantageous3 this effect of superficial conductors appears to depend on the removal of the electrical particles further out of the sphere of each other's influence40 ,what quantity of metal is requisite for a lightning rod8 ,he concludes from the results of a number of accidents that 8a copper rod inch diameter1 or an equal quantity of copper under any other form1 would withstand the heating effect of any discharge of lightning which has yet come within the experience of mankind40 ,practical deductions4--8,from the various enquiries contained in the first #abc pages of this book1 we arrive at the following deductions3-- 8#ast4 ,copper is the best kind of metal for a conductor4 8#bnd4 ,the quantity of metal should not be less than that represented by the section of a solid cylinder inch diameter4 8#crd4 ,the metal should be placed under as great an extent of surface as is consistent with strength1 and should be perfectly continuous4 8#dth4 ,the conductor should involve in its course the principal detached masses of metal in the building4 8#eth4 ,it should be placed as close as possible to the walls which are to be defended1 and not at a distance from them1 and be carried at once directly into the ground4 8#fth4 ,it should be attached to the most prominent points of the building1 and if the length be very considerable its dimensions should be increased4 8,lastly4 ,in extensive ranges of buildings1 all the most prominent parts should have long pointed rods projecting freely into the air1 and the greater the range of building the higher they should be4 8,in particular cases1 in which expense must necessarily be considered1 wrought iron tubing may be employed2 it should not1 however1 be less than #b inches in diameter1 and #c_/ajths of an inch in thickness40 ,insulating the lightning conductor from the building is quite valueless4 ,the method of fixing lightning conductors to ships is explained at considerable length4 ,range over which the protecting power of the lightning rod extends4--,great doubts exists as to the answer to this question1 since in many cases one portion of a building has been struck while a lightning rod in good condition existed close by4 ,for example1 the powder magazine at ,bayonne was #ef feet long1 #cf feet wide1 covered with thick vaulted masonry and a sloping roof with gable ends1 protected by plates of lead2 the gutters were also of lead1 and there were the usual spouts for discharging the rain4 ,the lightning rod projected about #bj feet above the building1 and was attached to the lead of the roof by a metallic socket through which it passed1 and which was soldered to one of the lead coverings4 ,instead of being carried1 however1 directly into the earth at the foot of the wall1 it was turned outward at about #b feet from the ground1 and being bent at right angles1 was continued on semi-insulating posts of wood into a trench filled with charcoal1 distant #cc feet from the wall4 ,on the #bcrd of ,february1 #ahbi1 the building was struck1 the point of the conductor melted1 and the leaden plates by which it was attached to the wood posts at the foot of the wall1 were more or less torn and perforated by holes4 ,no damage1 however1 ensued to the building in the course of the conductor4 ,at the south-west corner1 a sheet of lead covering the gable end was torn out immediately over a point where two stones of the cornice were united by an iron cramp4 ,sir ,w4 ,snow ,harris considers the possibility of this damage having arisen 8from the conductor 7in consequence of being continued at so great a distance from the building7 not offering a sufficiently easy line of transit for the discharge to the earth10 but he rejects this explanation and concludes that the damage arose from the lightning striking the building in two points4 ,again1 the ,heckingham poorhouse1 although armed with eight pointed lightning rods1 was struck1 in #aghg1 at a point m1 #gj feet from the nearest conductor c4 ,illustration3 ,view and ,plan of ,heckingham ,poorhouse ,illustration3 ,view and ,plan of ,heckingham ,poorhouse ,the squares at a1 b1 c1 d1 e1 f1 g1 h1 indicate chimneys to which lightning conductors were attached4 ,the centre range was #ajh feet long1 the flanks each about #afj feet long3 the details of the lightning conductors are not given4 ,one portion of the lightning discharge struck one of the conductors and was carried off by it without damage to the building1 one portion struck the building at the point m and also the shed at s1 doing some damage1 and a third portion struck the ground immediately in front of the building near a gate1 ,g4 ,the ship tna was struck in #ahcj by several heavy electrical discharges when at ,corfu4 ,these for the most part passed down a chain conductor attached to the mainmast4 ,one of the discharges1 however1 struck the ship near the bow1 and exploded about #ab feet above the forecastle close to the foremast1 knocking people down1 c4 ,the ,board-house at ,purfleet was a lofty building with a pointed roof1 well leaded and connected by lead gutters and pipes with the earth1 and with wells #dj feet deep for the purpose of conveying water forced up to a cistern on the roof4 ,it was1 therefore1 only thought necessary to add an iron spike about #aj feet long to the middle of the highest part of the roof4 ,the building1 however1 in #aggg1 was struck and slightly damaged at a point #df feet from the conductor4 ,several other examples illustrating how small an area a lightning rod protects follow4 ,sir ,w4 ,snow ,harris further concludes that experience shows that lightning will not leap from a lightning rod to a piece of insulated or semi-insulated metal near it1 although a discharge may take place between the rod and a distant metallic mass in connection with the earth1 but not otherwise in connection with the rod4 ,he lastly considers the question1 formerly much debated as to whether a lightning rod attached to a house will attract to the house a discharge that otherwise would not have struck it1 and he concludes that there is no foundation for the erroneous impression that the existence of a lightning conductor can ever cause damage4 ,,an ,,account ,,of ,,the ,,chimney ,,of ,,the ,,edinburgh ,,gas ,,works4 ,,by ,g4 ,,buchanan1 ,c4,e41 ,f4,r4,s4,e4 ,proceedings of the ,royal ,scottish ,society of ,arts1 #ahej-ea4 7,abstracted by ,g4 ,j4 ,symons1 ,f4,r4,s47 ,this chimney has a total height of #cda feet 7#cbi feet above ground71 it is circular2 at the top the internal diameter is #aa feet #d inches1 and the external #ac feet #aj inches2 and at the bottom1 internal diameter #bj feet1 external #bf feet #c inches4 ,respecting the conductor ,faraday was consulted1 and replied as follows3-- 8,the conductor should be of inch copper rod1 and should rise above the top of the chimney by a quantity equal to the width of the chimney at the top4 ,the lengths of rod should be well joined metallically to each other1 and this is perhaps best done by screwing the ends into a copper socket4 ,the connection at the bottom should be good2 if there are any pump pipes at hand going into a well they would be useful in that respect4 ,as respects electrical conduction1 no advantage is gained by expanding the rod horizontally into a strap or tube--surface does nothing1 the solid section is the essential element4#d ,there is no occasion for insulation 7of the conductor7 for this reason4 ,a flash of lightning has an intensity that enables it to break through many hundred yards 7perhaps miles7 of air1 and therefore an insulation of six inches or one foot in length could have no power in preventing its leap to the brickwork1 supposing that the conductor were not able to carry it away4 ,again1 six inches or one foot is so little that it is equivalent almost to nothing4 ,a very feeble electricity could break through that barrier1 and a flash that could not break through five or ten feet could do no harm to the chimney4 ,footnote #d3 ,the very reverse of what was formerly held by high authorities4--,note by ,editor of ,proc4 ,roy4 ,scot4 ,soc4 of ,arts4 8,a very great point is to have no insulated masses of metal4 ,if1 therefore1 hoops are put round the chimney1 each should be connected metallically with the conductor1 otherwise a flash might strike a hoop at a corner on the opposite side to the conductor1 and then on the other side on passing to the conductor1 from the nearest part of the hoop there might be an explosion1 and the chimney injured there or even broken through4 ,again1 no rods or ties of metal should be wrought into the chimney parallel to its length1 and therefore to the conductor1 and then be left unconnected with it40 ,in answer to some further inquiry1 ,professor ,faraday again wrote3-- 8,the rod may be close along the brick or stone1 it makes no difference4 ,there will be no need of rod on each side of the building1 but let the cast-iron hoop and the others you speak of be connected with the rod1 and it will be in those places at least1 as if there were rods on every side of the chimney4 8 rod is no doubt better than inch1 and except for expense ,i like it better4 ,but inch has never yet failed4 ,a rod at ,coutt's brewery has been put up at #a inch diameter--but they did not mind expense4 ,the ,nelson column in ,london has inch rod1 is better4 8,i do not know of any case of harm from hoop-iron inclosed in the building1 but if not in connection with the conductor1 ,i should not like it2 even then it might cause harm if the lightning took the end furthest from the conductor40 ,the following paragraph states what was done3-- 8,the electric conductor stands #f feet above the iron top-plate1 -inch round copper1 made fast to stone and brickwork with #g-;inch copper holdfasts let #d inches into the masonry or brickwork1 with a head on the inside and an eye on the outside to receive the rod as it was carried up4 ,by these holdfasts an ascent can easily be made to the top by a small tackle suspended to the holdfasts4 ,the conductor is metallically connected to all the ironwork on the stalk--the plate on the top1 projecting cope1 malleable iron hoops1 bolts on the top of stone pedestal1 and also the ascending chain4 ,the rod descends into a well about #aj feet from the foundation1 and is immersed about #h feet deep in water1 and the end turned up #b feet in a horizontal direction1 and flattened40 ,,papers relative to ,,shipwrecks ,,by ,,lightning1 as prepared by ,,sir ,,snow ,,harris1 and presented by him to the ,admiralty4 7,august #eth1 #ahed4 ,parliamentary ,paper4 ,fcap4 folio74 7,abstracted by ,professor ,w4 ,e4 ,ayrton74 ,number of merchant ships destroyed by lightning1 loss to the country4 ,application of lightning conductors to ships in #ahbj4 ,mode of applying them4 ,mechanical difficulties2 how overcome4 ,the saving to the ,exchequer which has resulted4 ,long account of various ships in the ,royal ,navy not provided with lightning conductors1 struck by lightning and damaged4 ,loss of life and injury that has resulted4 ,long account of ships provided with lightning conductors1 and so preserved4 ,sir ,snow ,harris states that 8although his system of lightning conductors ought to guard against all those violent and regular shocks of lightning falling within the ordinary experience of mankind1 it is not to be expected that the system could guard against every possible kind of atmospheric electrical discharge1 be the circumstances what they may1 such as thunderbolts1 fire-balls2 nor is it expected that it should guard against meteorolites1 or against sweeping electrical action mixed up with convulsions of nature2 nor can it quiet those minor electrical effects producing electric glow2 nor can it always obviate that tremendous concussion and expansion of the atmosphere in cases in which a thunder-cloud discharges its lightning in a dense explosion on the masts1 and which may rupture1 or mechanically tear to pieces1 frangible matter40 ,,statistics ,,of ,,buildings ,,and ,,ships ,,struck ,,by ,,lightning4 ,,by ,f4 ,,duprez1 ,,member ,,of ,,the ,,academy4 ,acadmie ,royale de ,belgique1 ,extrait du ,tome #ca des ,mmoires1 #eth ,december1 #aheg4 7,abstracted by ,professor ,t4 ,hayter ,lewis1 ,f4,s4,a47 ,m4 ,duprez refers to the ,report of a ,committee of the ,institute of ,france4 7,vide ,comptes rendus1 #aheb-f47 ,he divides the subject into the following heads3-- #a4 ,the frequency with which lightning rods are struck4 #b4 ,their terminal points and the effects of the stroke on them4 #c4 ,the conductors and their ground connections4 #d4 ,the protective power of the lightning rods4 #a4 ,concerning the frequency with which lightning conductors are struck by lightning4 ,the author cites #add cases of lightning rods having been struck4 ,of these seventeen were struck two or three times1 so that the total number of electric discharges on them was #afh1 as far as recorded4 ,but very many cases are not recorded at all1 e4g41 from #agic to #ahac only two cases were noted4 ,the great number of lightning rods struck would seem at first to support the idea that they attract lightning4 ,but we must compare the number of rods struck with those fixed1 and we find from a communication made in #aggg to the ,academy of ,berlin1 that1 even then1 a large number were fixed to the most important edifices of ,n4 ,italy and ,england4 ,the same in #aghd to those in the ports of ,france and to the ships in the said ports4 ,in #agid the fortresses of ,russia were ordered to be so protected4 ,in #agfi there were #aff edifices in ,hamburg alone1 and #ajd in its environs1 with conductors4 ,if the number of conductors were so great in the last century1 we must conclude that the number of those struck must be very inconsiderable as compared with those fixed4 ,in ,hamburg1 e4g41 not one rod is recorded as having been struck4 ,in #aghe1 ,ingen-,housz reports that of all the lightning rods placed by his direction on the ,austrian powder magazines and other buildings only one had been struck4 ,in #aggb1 ,franklin wrote1 that during the twenty years in the course of which lightning rods had been fixed in ,america he knew of five cases only in which these rods had been struck4 ,sir ,w4 ,s4 ,harris reports in #ahed1 as the results of twenty-two years' experience1 that the number of vessels struck unprotected by lightning rods1 as compared with that of vessels protected by his plan1 was as three to two4 ,the above show that the idea of danger from lightning rods is not well founded4 ,besides which it must be remembered that they are frequently placed in the most exposed positions1 e4g41 of the #add rods struck1 seventy-four were on ships1 and fifteen others on buildings which had been struck before4 ,one would think that the number of terminals placed on a building would diminish the chances of their being struck1 but it does not seem to be so2 e4g41 twelve buildings in the first list had many terminals communicating with a common conductor or different conductors4 ,yet the lightning struck1 with explosive effect1 one or other of the rods of these buildings4 ,and in each of two cases the lightning struck at once the three rods fixed to a building4 ,of the #add cases above cited3-- #gd were to lightning rods fixed on ships #cj were to lightning rods fixed on towers #i were to lightning rods fixed on powder magazines #ca were to lightning rods fixed on ordinary buildings4 ------ #add ,in forty-four cases where one of ,sir ,w4 ,s4 ,harris' conductors was fixed to each mast of a ship1 the mainmast was struck twenty-seven times2 the foremast was struck fourteen times2 the mizen was struck twice2 both the main and foremast twice4 #b4 ,as to the points of the lightning rods struck1 and the effect produced on them4 7,sir ,w4 ,snow ,harris's system as adopted in the ,british ,royal ,navy since #ahcj is described4 ,they are formed of bands of copper let into the masts4 ,they have no upper terminals or points1 and fifty-five are included in the list already quoted of #add lightning rods struck47 ,of the eighty-nine cases remaining in the list1 only fifty-one are recorded as having their upper terminals ended with points4 ,of these1 thirty had their points melted to a greater or less extent2 six of them were of copper or brass2 five were of copper gilt or iron gilt2 one was of brass silvered2 and four were of platinum4 ,the others are not distinctly described1 and the sizes seldom given4 ,one of brass was #bed centimetres 7c4 #aj inches7 long1 and #e millimetres 7th inch7 diameter at its base1 and was melted for th of its length4 ,one of copper was #bd centimetres 7c4 #i inches7 long1 and #i millimetres 7c4 rd inch7 diameter at base1 and was almost all melted4 ,one of platinum was #h centimetres 7c4 #c inches7 long1 and #a centimetre 7c4 rd inch7 diameter at base4 ,this was melted for a length of #e or #f millimetres 7c4 th inch47 ,it results from the above facts that the points of the lightning rods have been much too slender4 ,the ,institute of ,france recommends1 therefore1 for the points #b centimetres diameter 7c4 th inch7 at base1 and only #d centimetres 7c4 #a inches7 high1 with an angle of opening of #bh to #cj degrees4 ,it has been urged1 especially in ,germany1 against the employment of pointed upper terminals that these points are fused by the lightning1 this fusion being regarded as dangerous on account of its action on inflammable substances near4 ,as to this1 the author cites three cases of buildings set on fire1 though protected by lightning rods4 ,but the precise cause of the fire was not ascertained4 ,several observations show that the melted metal trickled down the side of the lightning rod4 ,at ,strasbourg the metal was pressed down on one side1 and had bent like wax softened by heat4 ,at other times the lightning disperses the melted metal in all directions4 7,examples quoted47 ,with these facts before us we cannot altogether deny that some danger may arise from the fusion of the metal at the point of the terminal4 ,but this danger can be much lessened1 if not removed1 by adopting the size1 etc41 of the lightning rods recommended by the ,institute of ,france4 ,besides fusion1 the points sometimes show distinct traces of mechanical action caused by lightning4 ,the author quotes six examples of this where the points had been curved4 ,this shows the necessity of strengthening the points of the upper terminals4 ,the curvature arises1 probably1 from the points being much heated by the lightning1 and acted on by the wind4 ,one case is noted of a point which had the appearance of having been struck violently by a hammer4 ,also of one in which the base of a point1 where it was screwed to the rest of the upper terminal1 was split for a length of #aa millimetres 7c4 inch74 ,also of a platinum point screwed on the upper terminal 7copper71 and retained by a pin1 where the stroke tore away the pin1 the point falling intact at the foot of the lightning rod4 #c4 ,of ,conductors of lightning rods struck1 and their contact with the ground4 ,the author refers to forty-one cases of lightning rods struck when not on ,harris's principle4 ,of these1 #e were of copper bands soldered together2 #e were of copper wire either as rope or chain2 #a was made of bands of sheet iron2 #aa were of bars of iron joined by screws or by solder2 #c had pieces of lead between the parts where they were screwed together2 #c were of simple iron wire1 or of rope or chain of iron wire2 #c were of iron joined together by hooks2 #ab are described as chains 7metal not specified72 #a is described merely as a conductor4 ,the dimensions of the above are seldom given4 ,the largest bands reported are #af centimetres 7c4 #f inches7 in width4 ,the largest bars reported are #ee centimetres 7c4 #b inches7 in width and #ae centimetres 7c4 inch7 in thickness4 ,the description of the earth connection is also imperfect4 ,of eighty-nine lightning rods described as struck1 only twelve are noted as having their ends in running water or wells1 and one in damp soil4 ,fifteen simply entered the ground1 it being noted expressly of six of these that it was dry4 ,in three cases were the lightning rods were struck the author found that the part at the base and in the damp earth had terminated in a plate of lead1 protected above the ground by a wooden enclosure4 ,three conductors of ships did not communicate with the sea4 ,twenty-three cases are noted of ordinary conductors 7not on ,sir ,w4 ,s4 ,harris's principle74 ,the lightning melted1 or reduced almost to powder1 three4 ,the first was on a house1 and was of copper wire1 the diameter not known1 ending with a chain of iron buried in the earth4 ,the second was on a ship's mainmast1 and was of iron wire #f millimetres 7c4 inch71 diameter1 #df centimetres 7c4 #ah inches7 long1 folded at their extremities1 and united by rings4 ,the third 7also to a ship7 was a rope of three strands formed in the whole of #fj brass wires1 each being one half to two-thirds of a millimetre thick4 ,the two last conductors had their ends in the sea4 ,the parts of these conductors1 in place of being soldered or screwed together1 were joined merely by hooks and rings like a surveyor's chain4 ,evidently a bad form as their contact is imperfect4 ,in three other conductors1 whose different parts were screwed together with lead between them1 the stroke melted the lead4 ,this shows the danger of lead from its fusibility1 in addition to its less conducting power4 ,the author gives examples of this1 wherein a leaden pipe1 #h centimetres 7c4 #c inches7 external diameter1 and #ac millimetres 7c4 inch7 thick1 was melted4 ,he quotes ,arago as calling attention to the importance of the form of the bends in conductors1 abrupt bends being dangerous4 ,two examples are quoted to prove this1 the conductors having been broken by the lightning stroke at a sudden bend4 ,to provide lest the lightning1 after having struck the lightning rods1 should abandon them for larger masses of metal near them1 these masses should be made to communicate with the conductors4 ,cases are cited where the lightning quitted the conductor and struck metallic bodies near4 ,also1 in respect of painting conductors1 the author quotes a case where part of a bell wire adjoined a lead pipe which communicated with the conductor4 ,part of the wire was painted in oil colour1 the other part not4 ,the latter was melted1 the first not1 but the paint 7though otherwise uninjured7 had ceased to adhere to it4 ,three examples are cited of danger from conductors ending in watertight tanks4 ,in one case the stroke broke the conductor4 ,in another it left the conductor and injured the building4 ,in the third it merely melted the point of the upper terminal4 ,nevertheless1 it often happens that the lightning1 in spite of imperfect communication with the earth1 disperses itself inoffensively4 ,out of fifteen cases of lightning rods struck1 in which the conductors were simply buried1 more or less1 in the soil1 they carried off the stroke in eleven without the buildings being injured1 or any trace being left of it1 except that the ground was upheaved where the latter was too dry4 ,the ,french ,institute1 in their report on the protection of the ,louvre1 considered it necessary to employ1 under certain circumstances1 a conductor with two branches1 the one descending into a subterranean source of water1 the other communicating simply with the surface of the earth4 ,on the other hand1 ,arago thought that conductors need not enter the ground1 but communicate only with a metallic surface lying on the ground4 ,this view is confirmed by the cases which the author mentions where the surface of the earth being wetted by rain formed a conductor4 ,nevertheless1 the two branches are desirable1 in case one should fail4 ,fifty-five conductors on ,sir ,w4 ,s4 ,harris's system are recorded as having been struck1 but the damage was quite trivial4 ,two electrical phenomena are to be noted as sometimes occurring when a lightning rod is struck4 ,first1 when a conductor is formed of metallic plates a peculiar noise is heard like water pouring on a fire4 ,second 7independently of the form of the conductor71 electric sparks are emitted from bodies near4 ,the author cites example at ,berne1 #ahae4 #d4 ,protective agency of lightning rods4 ,out of #afh cases of lightning rods struck 7vide page #ia7 there are only twenty-seven 7c4 th7 in which the buildings or ships have not been preserved1 and of this sixth many of the conductors were imperfect2 e4g41 four terminated in earth which was unusually dry1 and two of them were of insufficient size4 ,another was formed of pieces having their ends hooked4 ,two conductors ended in watertight tanks4 ,another was in the form of a surveyor's chain1 the parts not being1 consequently1 in close contact4 ,others were badly jointed1 or had imperfect communication with the ground or with the sea4 ,in two cases the stroke broke the conductor at points where its direction was abruptly changed4 ,in two other cases the lightning left the conductors struck1 and fell upon buildings near without causing damage to those on which the rods were fixed4 ,in the instance of a lightning rod fixed to the mainmast of the ,jupiter 7#ahed71 the conductor was made of sixty brass wires1 one half to two-thirds of a millimetre 7#jjb inch7 thick1 and was broken by the stroke into thousands of pieces4 ,the ,institute ,committee concluded that the lightning was not conducted by all the wires of the conductor4 ,those which it followed were insufficient to transmit it2 some were melted1 some broken4 ,the ,committee recommended1 therefore1 that each metallic wire be tinned separately at the extremity of the conductor1 and soldered thereto for a length of about a decimeter 7c4 #jd inch71 so as to form a metallic cylinder4 ,in the last six cases the particulars of the lightning rods are not given sufficiently to show the cause of their failure1 but five are described as being of chain or ropes of metal wire4 ,it results from the above facts that when the lightning rods have proved insufficient protection1 their failure has been owing to defects in their construction2 it is rather surprising to find how well buildings and ships have been protected1 even when the lightning rods have not been well constructed4 ,in every one of the fifty-five cases where ,sir ,w4 ,s4 ,harris's rods were fixed they have protected the ships1 except that not having points some slight damage has sometimes occurred to the tops of the masts4 ,this shows their superiority over ropes or chains4 ,arago thought that lightning rods were protection against ordinary lightning1 but not when it assumed the form of fire-balls4 ,the author cites several examples to show that this opinion was not well founded4 ,he considers a perfectly constructed lightning rod to be a perfect safeguard4 ,but he adds that the lightning stroke produces electric disturbances in its vicinity1 although the building be intact4 ,he cites an example of this in respect of a prison whose inmates 7#cjj7 experienced a great enfeebling of their muscular power during some seconds4 ,very few records exist relating to the area of action of lightning rods1 and the elements for determining their protective power are slight4 ,the author gives a table showing the heights of points1 horizontal distances1 c41 in certain cases1 and cites four instances of ships whose foremasts were struck although the mainmasts had lightning rods1 and one where the mizen was struck though the fore and mainmasts were protected4 ,,table ,,given ,,by ,m4 ,,duprez4 ,,in ,,metres4 ,,in ,,english ,,feet4 #ast #bnd #crd #dth #ast #bnd #crd #dth ,case4,case4,case4,case4,case4,case4,cas e4,case4 ,length of upper #ae #cd #ae #bc #e #aa #e #h terminal1 or height of point above that portion of the building on which the upper terminal was fixed4 ,vertical height of #ae #gf #fg #gab #e #be #bb #bcb point above the place struck4 ,horizontal distance #aeb #gc #agd #eii #ej #bd #eg #aig of place struck from the base of upper terminal4 ,these instances show that we should be misled in considering1 as being protected1 a circular space whose radius was double the height of the lightning rod4 ,the protected radius appears to be only equal to double the simple height of the upper terminal above any required point1 and reckoned horizontally from a point vertically under the conductor4 ,it will be observed that ,m4 ,duprez here contradicts himself in two consecutive sentences1 and in a subsequent part of his work 7p4 #cj7 of the ,memoir1 he again says3 8,aucun des cas indiqus dans le numro prcdent n'infirme la rgle gnralement admise1 savoir que la sphre d'action d'un paratonnerre s'tend1 dans toutes les circonstances1 un espace circulaire d'un rayon gal au double de la longeur de la tige1 c'est-a-dire de la hauteur de la pointe au-dessus de la partie du btiment sur laquelle la tige est fixe40 ,but the table given by ,m4 ,duprez gives two instances in which the stroke fell within the radius of once the height4--,ed4 ,,resum4 ,in the paragraphs which the author numbers #a1 #b1 #c1 #d1 and #f1 he refers to former statements as to the proportion of lightning rods struck1 c4 7,vide page #ia1 c47 #e4 ,there being several terminals on an edifice does not seem to diminish the chances of each being struck4 #g4 ,in vessels1 when the three masts have lightning rods1 the mainmast is most frequently struck4 #h4 ,refers to ,sir ,w4 ,s4 ,harris's lightning rods as being without terminal rods or points4 #i4 ,the points of ordinary lightning rods have been made too slight4 #aj4 ,out of fifty-one cases of lightning strokes1 thirty points have been more or less melted2 and the fusion is not without danger to the buildings4 #aa4 ,the lightning often leaves traces of mechanical action more or less decided4 #ab4 ,refers to defective constructions of ordinary lightning rods4 #ac4 ,lead plates in conductors composed of bars joined together are dangerous4 #ad4 ,so are abrupt bends4 #ae4 ,conductors should communicate with the masses of metal near4 #af4 ,and must not end in watertight tanks4 ,but #ag4 ,conductors often protect buildings1 though the ground connections are imperfect4 #ah4 ,it is well for a conductor to have two branches1 viz41 one in water1 and the other on the surface of the ground4 #ai1 #bc4 ,refers to the complete efficiency of ,sir ,w4 ,s4 ,harris's conductors4 #bj4 ,mentions the noise1 electric sparks1 c41 given off during a stroke1 as before stated 7page #ie74 #ba4 ,mentions the efficacy of lightning rods generally4 #bb4 ,their failure being owing to defective construction4 #bd4 ,there is no proof that the electricity being in the form of a ball has been the cause of any conductor's inefficiency4 #be4 ,the lightning rarely bursts on a building or ship without striking the lightning rod placed on it4 ,exceptions have1 however1 occurred in ten cases1 as here described4 ,but #bf4 ,none of these instances invalidate the rule generally admitted1 that the protective action of the lightning rod extends1 under all circumstances1 to a circular space whose radius is equal to double the length of the upper terminal1 i4e41 the height of the point above the part of the building on which the upper terminal is fixed4 ,,on ,,atmospheric ,,electricity4 ,,by ,,reuben ,,phillips4 ,,london1 #ahfc4 7,abstracted by ,w4 ,h4 ,preece1 ,c4,e47 ,this is a pamphlet of seven chapters1 and fifty-seven pages1 written to ventilate the author's own notions of the nature of electricity and its production in the atmosphere4 ,he considers electricity to be two fluids of a species of substance1 consisting of separated subsidiary atoms4 8,electricity is comparable to a flying bullet2 the vis viv of the bullet is like electrical intensity1 and the mass of the bullet answers to the quantity of electricity40 ,what the subsidiary atoms are like he does not say4 ,chapter ,i4 is a fair resum of what is known of the electricity evolved by the friction of wet steam against solids in the hydro-electric machine4 ,he agrees with ,faraday that the cause of the evolution of electricity by the liberation of confined steam1 is not evaporation1 but the friction of the water particles against the sides of the jet-piece or orifice4 ,pure gases do not excite electricity2 but impure air1 when compressed does1 from the friction against the orifice of those particles of water which are suddenly condensed by the cooling influence of the expanding air4 ,chapter ,,ii4 is an attempt to show that electricity is evolved by the friction of 8gaseous matter0 against water1 or vice vers4 ,ordinarily the issuing vapour in the hydro-electric machine is positively1 and the boiler negatively1 electrified2 but cases occur where this is reversed4 ,according to the author1 water by friction against gaseous matter or air1 becomes positively electrified4 ,chapter ,,iii4 applies this theory to thunder clouds1 which are formed by the rapid inter-mixture of masses of the atmosphere thrown into circulation by heat4 ,there are some capital descriptions of thunder clouds4 ,they are often accompanied by whirlwinds1 and always by rain4 ,it is the friction of the whirlwind on the drops of rain that developes electricity--the rain being positively1 and the air negatively1 electrified4 ,hail is due to the ascending current of air carrying the drops of water to the region of snow and frost6 ,his notions are somewhat hazy1 thus3--8,much of the positive electricity is conveyed to the earth by the lightning2 but the corresponding negative electricity from being carried upwards with the vertical wind1 cannot so easily escape to the earth1 so that the storm cloud contains1 on the whole1 more negative electricity than positive electricity0 7p4 #ch47 ,chapter ,v4 contains the author's explanation of fire-balls1 which he supposes to be a 8glowing discharge10 preparatory to the final spark or flash of lightning4 8,probably most of the shooting stars are merely electrical fire-balls high up in the atmosphere0767 ,chapter ,,vi4 is devoted to the ,aurora ,borealis1 which plays about the magnetic pole1 and is an electrical phenomena of the upper strata of the atmosphere2 and ,chapter ,,vii4 is an attempt to explain the auroral light as 8probably produced by the collision of the subsidiary atoms when they are in the act of electro-apposition40 ,the pamphlet is said to be a condensed account of the discoveries of the author in matters connected with atmospheric electricity--discoveries which were described in papers handed to the ,royal ,society1 but which that ,society did not read4 ,the ,royal ,society were wise4 ,,le ,,coup ,,de ,,foudre ,,de ,l',,ile ,,du ,,rhin ,,pres ,,de ,,strasbourg4 ,,par ,m4 ,f4 ,,hugueny4 #dto4 ,paris4 #ahfi4 7,abstracted by ,g4 ,j4 ,symons1 ,f4,r4,s47 ,a very full account of an accident by ball lightning4 ,the facts are set out as clearly as possible1 the authority is given for every statement1 and most carefully engraved plans and engravings are given of all the necessary details4 ,it does not bear upon the question of lightning conductors except in that it shows that a discharge of globular lightning traversed a horizontal distance of #iai yards1 passed in front1 but below the top1 of a building which had three good conductors upon it and struck a chestnut tree1 which was by no means the highest tree in the locality4 ,,directions ,,for ,,constructing ,,lightning ,,rods4 ,from 8,essays on ,meteorology10 by ,,professor ,,joseph ,,henry4 7,smithsonian ,miscellaneous ,collections4 #hvo41 #ahga47 7,abstracted by ,a4 ,j4 ,frost74 #a4 ,the rod should consist of round iron1 of not less than of an inch in diameter4 ,a larger size is preferable to a smaller one 7ordinary gas pipe may be employed74 ,other forms of rod1 such as flat or twisted1 will conduct the lightning1 and in most cases answer sufficiently well4 ,they tend1 however1 to give off lateral sparks from the sharp edges at the moment of the passage of the electricity through them1 which might1 in some cases1 set fire to very combustible materials4 #b4 ,it should be throughout its whole length in perfect metallic continuity1 either by screwing the parts firmly together or by welding4 #c4 ,the rod should be covered with a coating of black paint4 #d4 ,it should be terminated above with a single point1 the cone of which should be encased with platinum not less than #a_/bj inch in thickness4 #e4 ,the shorter and more direct the rod is in its course to the earth the better2 acute angles should be avoided4 #f4 ,it should be fastened to the house by iron eyes1 which may be insulated by cylinders of glass2 this1 however1 is not absolutely necessary4 #g4 ,the connection to the earth should be as perfect as possible--in cities nothing is better for this purpose than to unite it to the gas or water pipes4 ,when a connection cannot be formed in this way the rod should terminate in a well containing water1 or if this is not practicable it should terminate in a plate of iron1 or some other metal buried in moist ground4 ,it should1 before it descends to the earth1 be bent1 so as to pass off nearly at right angles to the side of the house1 and be buried in a trench1 surrounded with powdered charcoal4 #h4 ,the rod should1 in preference1 be placed on the west side of the house1 and on chimnies where a current of heated air ascends during the summer season4 #i4 ,a single rod may be placed on small houses1 and its elevation should be at least half of the distance to which its protection is expected to extend4 #aj4 ,metallic roofs should be united with the lightning rods4 #aa4 ,as a general rule1 large masses of metal within the building1 particularly those which have perpendicular elevation1 ought to be connected with the rod4 ,,on ,,lightning ,,and ,,lightning ,,conductors4 ,,by ,w4 ,h4 ,,preece1 ,mem4 ,inst4 ,c4,e4 7,journal of the ,society of ,telegraph ,engineers1 #bg ,november1 #ahgb47 7,abstracted by ,prof4 ,t4 ,hayter ,lewis1 ,f4,s4,a47 ,the author refers to the ,escurial having been on fire seven times--four of them certainly from lightning2 yet no lightning conductor is fixed even now4 ,the average deaths from lightning in ,england are eighteen per annum2 in ,france1 ninety-five4 ,from ,january #a1 to ,july #ca1 #ahgb1 #ibf per cent4 of instruments1 of different forms1 used in the telegraph offices1 were injured by lightning4 ,electricity is force1 not matter1 and ,current is a well-defined term which implies a transference of electricity from one place to another4 ,thunderstorms differ only in degree from the phenomena which cause the ordinary snapping sparks from the machine4 ,in any case there must be two conducting masses in opposite electrical states1 separated by a non-conductor or dielectric4 ,the light is the effect of the discharge1 and is simply incandescent matter4 ,it indicates the path of the discharge and nothing more4 ,death by lightning is painless4 ,potential is that function of electricity which determines its motion from one point to another4 ,the path of electrical discharge is prepared beforehand by induction4 ,the particles of air1 c41 are in a state of 8tottering equilibrium40 ,a moving ship1 a man on horseback may destroy this1 and we have a discharge with all the effects of light1 heat1 and mechanical energy4 ,it is very doubtful whether thunder-clouds are themselves the sources of electricity1 producing thunder and lightning2 they are more probably1 mere accumulators as the coatings of a ,leyden jar4 ,clouds have been known to be absent during a discharge4 ,moreover1 the charge of a ,leyden jar exists not in the coatings but in the dielectric separating them4 ,so the discharge exists in the air and not in the clouds4 ,sheet lightning is a mere reflection of forked4 ,evidence proves that some such phenomena as ball or globular lightning exists1 and an explanation of it has been given by ,c4 ,varley4 ,discharge is invariably through the line of least resistance4 ,it may be through metals1 bricks1 trees1 animals1 and not always in a single track2 it is often divided into two1 three1 or even four lines4 ,thus1 an electrical discharge in air1 is simply a discharge between two electrified conductors1 of such different potentials as to break the resistance of the dielectric separating them4 ,there is nothing hidden1 mysterious1 or unknown in it4 ,a ship is a prominent object2 generally a conductor1 and reduces the line of resistance between the sea 7inner coating7 and the cloud 7exterior coating of the condenser7 determining discharge4 ,trees1 buildings 7except tall spires1 c47 are less prominent4 ,the effects of lightning experienced on telegraph wires1 poles1 and instruments by direct discharge are less numerous than those by induction1 and seldom destructive4 ,there were only two cases in the past season where line wires 7,no4 #h iron1 diameter #jagj inch7 were absolutely fused4 ,accumulation of a charge upon a cloud converts it into a powerful inducing body4 ,it induces in the wire an opposite electrical state4 ,discharge takes place4 ,the cloud suddenly loses its coercive power4 ,the wire recovers its neutral condition1 and produces a powerful current in opposite direction4 ,wires are affected although buried two feet underground4 ,unprotected poles are often destroyed4 ,in one case1 twenty successive poles were so4 ,instruments have had their cases burst out1 wood-work has been burnt1 and the wires of electro-magnets1 c41 been fused4 ,clouds are not perfect conductors1 so do not part with all their discharge at once4 ,there may be several successive discharges4 ,protection4--,sir4 ,w4 ,s4 ,harris's system approved4 ,houses4--,unnecessary expense is often incurred in protecting them4 ,a warm flue1 terminating in a metal grate1 is a dangerous conductor1 as it ends in the room and not in earth3 hence so many accidents indoors4 ,a lightning conductor should expose a prominent metallic point1 and offer a path of little or no resistance thence to earth4 ,hitherto expensive plates or ropes have been used for this4 ,but the author thinks galvanized iron wire inch diameter amply sufficient for any dwelling house4 ,telegraphic poles1 protected by lightning conductors of ,no4 #h wire 7 the above size71 have never been injured4 ,in one case1 fifteen per cent4 of unprotected poles have been struck4 ,but no case of damage has occurred for many years since the poles were earth-wired4 ,the cross-arms are often damaged as far as the earth wires1 never below4 ,the author can conceive no case in which inch standard galvanized iron wire is not ample4 ,the conductor should be solid and continuous from the gilded or platinum point to the ground4 ,joints should be well soldered4 ,chains and linked rods should not be used4 ,earth connections should be formed with iron gas- or water-mains1 or be several feet in coke1 or in a well4 ,each conductor should make a separate earth4 ,all masses of metal in the line of probable discharge are to be connected with conductor4 ,conductors should be examined periodically1 they should not be insulated1 nor be near soft metal gas-pipes1 nor bent in acute angles4 ,the area of protection appears to be that of a cone1 whose radius is equal to the height of the conductor4 ,one conductor is enough for small houses1 but each stack of chimneys should have one in connection with the main conductor4 ,lead roofs and iron pipes are easily made into protectors for buildings4 ,details given for protecting telegraph apparatus4 ,the telegraph companies abandoned the use of protectors4 ,the ,post ,office re-introduced them with good results4 ,the ,indian telegraph apparatus is protected1 and accidents scarcely ever occur4 ,prevention4--,points prevent the accumulation of charges4 ,but with very tall conductors--as to spires--a current results constantly in one direction1 producing electrolytic action and destruction of conductor1 as proved by one at ,llandaff ,cathedral4 ,so earth should be made with large masses of metal1 as gas- or water-mains4 ,galvanised iron fastenings should not be used to secure copper conductors to buildings1 as galvanic action would be set up4 ,appendix4--,letters quoted from ,mr4 ,latimer ,clark and ,dr4 ,faraday as to damage to underground wires from lightning4 ,the ,discussion on ,mr4 ,preece's paper was conducted by ,prof4 ,abel1 ,capt ,d4 ,galton1 ,mr4 ,g4 ,j4 ,symons1 who referred to ,dr4 ,franklin's suggestion as to cold fusion1 ,prof4 ,ayrton1 who entered at length into the system of prevention used with the ,indian telegraphs1 ,sir ,w4 ,thomson1 and ,mr4 ,latimer ,clark4 ,mr4 ,preece replied1 more especially alluding to the phenomena of fire balls4 ,,lightning ,,rods ,,and ,,how ,,to ,,construct ,,them4----,,by ,,john ,,phin1 ,c4,e4 ,new ,york4 #ahgc4 7,abstracted by ,w4 ,h4 ,preece1 ,c4,e47 ,the author is not an electrician nor a patentee1 but the ,editor of an engineering paper called the ,technologist4 ,the book is written chiefly to counteract the machinations of a great nuisance in the ,united ,states1 called the 8lightning rod man40 ,the ,author thinks a good rod as important as a fire insurance policy4 ,every case of injury that he has examined was due to defective rods1 or to the absence of them4 ,the lightning rod is an ,american invention4 ,he mentions several cases of marked immunity from accident due to proper conductors1 notably ,st4 ,paul's and the ,monument1 ,london2 the ,cathedral1 ,geneva2 and ,st4 ,mark's1 ,venice4 ,the lightning rod should form the path of least resistance1 and it may be of iron or of copper4 ,if of iron he prefers a flat bar #a inch by inch1 weighing #ac ounces per foot1 or ,no4 #jj copper1 weighing #f ounces per foot4 ,he also advocates copper rope4 ,he thoroughly believes in the conduction through the mass of the metal1 and quotes 7p4 #ab7 several experiments in support of that view4 ,he believes in a good earth and in connecting all waterspouts1 eaves1 gutters1 and metal work generally with the earth and with the conductor2 he thinks one good rod enough1 and sees no reason why lightning rods should not be painted1 indeed1 thinks it better to do so1 for they become less unsightly2 he has no faith in points1 nor in gilding1 or platinising2 he recommends instead cast iron caps to chimneys2 he discards insulation as absurd1 and suggests that rods may be tacked1 or stapled1 or strapped to buildings1 although he prefers staples2 recommends strongly that wet earth should be reached1 and that as large a metal surface as possible should be exposed to the ground and embedded in coke2 he does not like any connections with the gas pipes4 ,he suggests that iron conductors may be welded or have merely butt joints1 but recommends solder with copper1 after being bound with fine wire4 ,he adduces the fact that ,mr4 ,brooks1 of ,philadelphia1 measured the resistance of three rods attached to three buildings that had been damaged1 and found the average to be above the resistance of one hundred miles of telegraph wire4 ,,trait ,,des ,,paratonneres1 c4 ,,par ,a4 ,,callaud4 ,paris4 #ahgd4 ,royal #hvo4 7,abstracted by ,latimer ,clark1 ,c4,e47 ,this work consists of #aga pages4 ,it commences with a short history of the subject1 which occupies the first chapter4 ,the remaining nineteen chapters treat successively of the collecting points and their mode of action2 the conducting rods and the methods of attachment to different classes of building1 and their connection with the earth1 with concluding observations4 ,the second chapter treats of the height of conductors and the area protected1 in which he follows the usual rules1 and recommends lofty rods1 their office being not only to safeguard the building1 but to withdraw electricity silently from the air and thus prevent strokes of lightning or diminish their violence4 ,in ,chapter ,,iii41 after citing the opinions of many other writers1 he strongly advocates protectors furnished with sharp points of platina1 or some inoxydisable metal1 securely screwed and soldered on to copper rods1 and condemns points of iron or copper4 ,throughout the work he treats cost as a secondary consideration and considers it false economy to spare any expense necessary to ensure the thorough perfection of the whole system4 ,in ,chapters ,,iv41 ,v41 and ,,vi4 he gives drawings of connections and of various forms of weathercocks4 ,in ,chapter ,,vii4 he recommends multiple points1 especially in mountainous countries and where storms are prevalent4 ,he also points out that many buildings are naturally protected by the metal roofs and ornaments belonging to them4 ,so long as these are connected with the ground1 he prefers that the projecting rod should be of round iron of considerable length and in one piece1 and the conducting cable should wind round it as a collar1 and be strongly attached to it by set screws and soldering4 ,he does not advise that all the masses of metal within a building should be connected with a conductor1 especially if they are in proximity with human beings1 but with a well-made conductor he considers it safer to leave them isolated4 7,chapter ,,ix47 ,for the conductor he recommends ,gay ,lussac's construction1 viz41 a rod of iron about inch square1 carried by iron supports1 or a twisted cable of iron wires having a diameter of inch to inch1 well tarred or galvanised1 #f or #h feet from the soil these are securely united to an iron bar inch to #a inch diameter4 ,if of copper they may be smaller4 ,has seen rods of copper of inch effectually protect churches1 but regards this as a minimum size for a length of #hj feet and inch as a maximum4 ,the single wires of the cords may have a diameter of #a millimetre2 the joints are made by splicing the strands together and soldering them4 7,he recommends conductors of straw in some cases for country use4 ,chapter ,x47 ,the conductor is led along the ground in a channel of half drain tiles1 surrounded with coke and terminates in a copper grapnel embedded in a basket of coke4 7,chapter ,,xiii47 ,chapters ,,xiv41 ,,xv41 and ,,xvi4 gives details of the construction of lightning conductors for tall chimneys1 powder magazines1 and ships4 ,in ,chapter ,,xviii4 he gives numerous examples of the utility of conductors1 and in ,chapter ,,xix4 he gives a resum of his instructions1 again insisting on the perfect continuity of the connections and the perfection of all the parts2 these instructions are also embodied in a note read before the ,academie des ,sciences1 in #ahfb1 a copy of which is given at page #afg of ,m4 ,callaud's work4 ,,blitzableiter-,,anlagen4 ,,prof4 ,c4 ,,zenger',s ,,symmetrische ,,blitzableiter4 ,c4 ,korte and ,co41 ,prague4 7,abstracted by ,g4 ,j4 ,symons1 ,f4,r4,s47 ,this is really a trade circular1 but it gives1 in a compact form1 the considerations which have induced ,prof4 ,zenger to propose his new system1 and a description of the mode in which it is carried out4 ,in the first place it may be well to reprint from the ,meteorological ,magazine1 ,vol4 ,,viii4 7#ahgc71 page #aee1 the report of the paper read by ,prof4 ,zenger at the ,british ,association ,meeting4 ,,prof4 ,,zenger1 ,,on ,,the ,,action ,,of ,,symmetrical ,,conductors ,,and ,,lightning ,,conductors4 ,professor ,zenger read a paper1 on this subject1 illustrating it with the well-known experiment in physics of placing two insulated hemispheres of brass plate in contact with another insulated sphere of brass4 ,if the former were charged with electricity and removed from the inner brass sphere1 there was found no trace of electricity on its surface4 ,the electricity was shown to be accumulated on the surface of the outer spherical conductor1 with equal tension in every point of the surface4 ,professor ,zenger showed that if the outer hemispheres were replaced by two circular wires1 no action whatever in the inner conductor was found4 ,he said it was easy to see that this simple experiment might prove useful in regard to the construction of electric apparatus and of lightning conductors to protect buildings1 and even whole cities1 from the destructive action of atmospheric lightning4 ,he had1 therefore1 endeavoured to ascertain the effects if any other form of a symmetrically-arranged conductor were used1 instead of a circular form4 ,in the first instance1 he had tried the parabolic wires joined to the electroscope2 next1 a rectangular wire with five different openings4 ,if placed exactly in the middle of the rectangular wire1 no action was observed2 if placed eccentrically1 however1 there was small but increasing action2 and if he placed a needle or another sharp-pointed instrument between the protecting wire and the electroscope1 he still better observed the different action produced by placing the electroscope in an eccentrical position4 ,he therefore thought that it was possible by symmetrical wires placed on buildings1 or over whole cities1 so to procure an entire protection from atmospherical electricity4 ,if the electric clouds should even enter between the objects protected and the protecting wires1 their activity would be greatly diminished1 for the wires would become immediately charged1 and nearly all the electricity accumulated on their surface without any danger to the protected buildings4 ,mr4 ,glaisher1 who had taken the chair in the temporary absence of the president1 said their thanks were due to ,professor ,zenger for his communication upon a subject so important4 ,what they wanted to know was the distance at which buildings were protected by a lightning conductor1 and ,professor ,zenger's assertion that the sections of a globe were as effective as the whole globe itself1 would be an important addition to scientific knowledge if proved to be so4 ,professor ,clerk-,maxwell1 who said he had paid some attention to the subject of shielding bodies from electrical action by means of the wire1 feared that the form that ,professor ,zenger had given them would be rather difficult to work out mathematically4 ,professor ,zenger said that the correspondent of the ,engineer newspaper had just informed him that the instrument hut of the ,atlantic ,telegraph ,company at ,valencia was protected by wires on the principle he had just mentioned1 and the plan of protecting the hut had been devised by ,mr4 ,cromwell ,varley4 ,we now pass on to ,messrs4 ,korte's paper1 which refers entirely to the application of this symmetrical principle to buildings4 ,they begin by claiming that ,prof4 ,zenger's system is the only one based upon scientific investigations and practical experiments1 and that although far better than the primitive arrangements generally adopted it costs no more4 ,they urge that the conductors should be symmetrically arranged1 and yet they say that they should lead to the side of the house most exposed to the weather4 ,they recommend that the upper terminal should be a long oval of gilt brass1 something like a blunt spear-head1 and that1 in ordinary cases1 a single copper rod of #jbj inch diameter 7not a rope of that size7 will be sufficient2 it is to be taken through porcelain insulators1 and the earth terminal is to be a copper plate nearly of an inch thick1 buried from #f to #i feet deep in coke4 ,,protection ,,of ,,life ,,and ,,property ,,from ,,lightning4 ,by ,w4 ,,mcgregor4 ,bedford1 #ahge4 #hvo4 #dc pages4 7,abstracted by ,latimer ,clark1 ,c4,e47 ,mr4 ,mc,gregor does not give any new facts in connection with lightning1 but discusses the theory and action of conductors1 and quotes numerous opinions from other writers1 with practical suggestions and precautions to be observed in fixing conductors4 ,among the principal opinions adduced are the following3-- #a4 ,professor ,jenkin's statement1 that if a conductor be armed with a point1 the electricity passes into the air rapidly in times of excitement by induction1 and so equalises the tension of the surrounding atmosphere as to mitigate1 or1 in some cases1 to prevent the discharge of lightning4 #b4 ,de la ,rive's observation that a slight break of continuity in a conductor is filled by a succession of brilliant sparks during a storm1 though there be no lightning2 that blunt points or balls are equally effective when struck1 but are more usually accompanied by explosion than by continuous discharge4 #c4 ,the opinions of ,de la ,rive1 ,dr4 ,mann1 and ,preece1 that a conductor practically protects a conical space--of which the radius is about double the height--and that the conductor should therefore extend to some height above the building4 #d4 ,ganot's opinions that a conductor should terminate in a point or points1 have sufficient sectional area1 be thoroughly connected with the earth1 and be connected with lateral metallic surfaces of large extent if it passes near them2 either iron or copper may be used1 and existing rain and water pipes1 c41 may be utilised2 but the joints should be made carefully and tested4 ,chimneys with soot act as dangerous conductors1 and should therefore be protected4 ,the author does not give any precise directions as to the best form or size of conductors4 ,,lynildens ,,farlighed ,i ,,norge4 ,,by ,h4 ,,mohn1 ,kristiania4 #ahge4 7,abstracted by ,c4 ,terkelsen47 ,the author1 having been specially commissioned to enquire into and investigate the danger of lightning in ,norway1 found that lighthouses1 telegraph stations1 and other much exposed buildings1 which were provided with conductors1 did not by far suffer so much as churches1 which in the most cases were unprotected4 ,out of about #ajj churches reported to have been struck by lightning1 only three were provided with lightning conductors3 on the first1 ,kongsberg1 the conductor was in good order1 and the church was comparatively uninjured2 the second church1 ,fossnes1 built of wood1 had a conductor1 but made of zinc wire1 which melted1 and of course left the church unprotected2 on the third1 ,brn 7struck #agth ,october1 #ahgb71 the wire had rusted1 where it joins the earth1 and the church was destroyed4 ,the author gives a full description of the different cases4 ,of #ajj churches struck by lightning1 fifty-six were totally destroyed1 and had to be rebuilt2 twenty-four of that number were churches built of stone1 twenty-nine of wood2 the building material of the remaining three is unknown4 ,it would thus appear that stone buildings are almost as much exposed to be damaged by lightning as wooden ones4 ,of the above-named churches only one can be said to have been saved by a lightning conductor1 viz41 ,kongsberg4 ,in #ahbj the lightning struck the church1 set fire to a great part of the wood-work1 and did other damage4 ,the tower was then covered with sheet iron4 ,in #aheb the lightning struck the tower again1 which1 however1 then was provided with a conductor consisting of two thin copper plates1 #b inches wide1 fastened on the north and south side of the tower1 and both beginning with the iron rod1 on which the vane is fastened2 but this rod did not end in a point1 but in a gilt cross4 ,the conductors were carried down the brickwork of the church to the field1 and across the market place1 and ended in an old water-butt4 ,when the concussion took place one of the lightning conductors was disabled2 but no material injury was done to the tower4 ,in #ahgb1 ,july #afth1 the lightning struck a farmhouse about #gjj feet from the above-mentioned church2 the farmhouse being about thirty feet1 and the tower about #aej feet high4 ,the construction of a lightning conductor ought to be as follows3 ,it consists of the following three chief parts4 7#a7 ,the receiver2 7#b7 the conductor2 7#c7 the earth connection4 ,the receiver consists of a copper point #h inches long and inch thick2 which is screwed into an iron rod1 #a to #b inches thick4 ,the screw must fit well and the flats of the copper and iron fittings must be well connected and afterwards soldered round the joint to prevent water and air from rusting the iron4 ,there are various ways of fastening the receiver to the building1 but the engineer is generally guided by circumstances4 ,the conductor may be made of iron or copper in the shape of rods or wire twisted like rope4 ,if made of iron rods they should be round and to inch thick2 if iron wire-rope is used the thickness must be equal to a rod of inch2 if made of copper the rod must be at least inch thick1 or if made of copper wire-rope inch4 ,in both cases the conductor is put in metallic connection with the receiver1 and then guided into earth4 ,the earth connection is merely a continuation of the conductor and must be buried as deep as possible in the earth1 and reach the water1 if it is to be found4 ,the end which reaches the water may be constructed in various ways1 according to circumstances1 but it is of the greatest importance that the earth conductor never gets dry4 ,if there is great difficulty in getting at the water1 the earth conductor may be constructed in the following manner4 ,it is made of copper1 and has joined to it as many branches as are thought necessary4 ,each branch has rivetted or soldered to it a copper plate #a or #b feet square2 they are carried as far away from the building as possible1 and buried deep into the earth4 ,besides this there must be laid an extra conductor1 perfectly metallically connected with the chief conductor just under the surface of the earth1 alongside of it1 out from the building1 with as many branches1 and as long1 as possible4 ,this conductor becomes efficient1 as soon as the surface of the earth gets wet through rain1 which generally falls during a thunderstorm4 ,,lecture ,,delivered ,,before ,,the ,,society ,,of ,,arts1 #bhth ,april1 #ahge4 ,by ,r4 ,j4 ,,mann1 ,m4,d4 7,abstracted by ,e4 ,e4 ,dymond1 ,f4,m4,s47 ,draws attention in the first place to certain established principles4 ,different powers of various substances for conducting electricity4 ,electrical induction4 ,in dull fine weather the surface of the earth negative1 the surrounding air commonly positive1 the surface of the sea positive4 ,how a thunder storm begins1 gradually approaching cloud1 lightning between it and earth4 ,according to ,delisle and ,petit1 a lightning stroke may extend #i or #aj miles1 but for ordinary circumstances the striking distance varies between #fej and #f1ejj feet4 ,the lightning stroke follows the line of least resistance1 and invariably falls upon the most prominent conducting substance1 and passes through substances affording an easy way and offering small resistance without disturbing their molecular condition2 shatters bad conductors2 heats1 sometimes melts1 good but insufficient ones4 ,describes the various forms of lightning--flash1 diffused1 sheet1 and ball4 ,a continuous rod of good conducting metal must be carried from the top of the building to the ground4 ,describes varying carrying capacities of iron1 zinc1 or copper2 recommends from his experience in ,south ,africa1 #db-strand rope of #a_/afth inch galvanised iron wire4 ,the disintegrating energy is mainly expended on the extremities of the conductor4 ,in ,natal he used to enclose the top of the rope in a tube of stout zinc1 finished at the top by a gilded ball of wood1 and he opened the strands of the wire above it into a brush4 ,the ,french electricians strongly recommend a cluster of points4 ,the earth contact must be good and damp4 ,the ,french system of ,callaud described4 ,gay ,lussac recommended that all large metallic masses should be brought into connection with the conductor1 and the conductor not insulated from the building4 ,m4 ,callaud1 on the contrary1 adopts insulating supports for the conductor1 and condemns the connecting of metals in the building4 ,the metals used in the construction of the buildings may be utilised as conductors2 rain pipes1 metal ventilating pipes1 but not soft metal gas pipes4 ,,on ,,the ,,protection ,,of ,,buildings ,,from ,,lightning4 ,,by ,,professor ,j4 ,,clerk ,,maxwell1 ,f4,r4,s4 7,reprinted from the ,report of the ,british ,association for the ,advancement of ,science1 #ahgf47 ,most of those who have given directions for the construction of lightning conductors have paid great attention to the upper and lower extremities of the conductor4 ,they recommend that the upper extremity of the conductor should extend somewhat above the highest part of the building to be protected1 and that it should terminate in a sharp point1 and that the lower extremity should be carried as far as possible into the conducting strata of the ground1 so as to 8make0 what telegraph engineers call 8a good earth40 ,the electrical effect of such an arrangement is to tap1 as it were1 the gathering charge1 by facilitating a quiet discharge between the atmospheric accumulation and the earth4 ,the erection of the conductor will cause a somewhat greater number of discharges to occur at the place than would have occurred if it had not been erected1 but each of these discharges will be smaller than those which would have occurred without the conductor4 ,it is probable1 also1 that fewer discharges will occur in the region surrounding the conductor4 ,it appears to me that these arrangements are calculated rather for the benefit of the surrounding country1 and for the relief of clouds labouring under an accumulation of electricity1 than for the protection of the building on which the conductor is erected4 ,what we really wish is to prevent the possibility of an electric discharge taking place within a certain region1 say1 the inside of a gunpowder manufactory4 ,if this is clearly laid down as our object1 the method of securing it is equally clear4 ,an electric discharge cannot occur between two bodies unless the difference of their potentials is sufficiently great compared with the distance between them4 ,if1 therefore1 we can keep the potentials of all bodies within a certain region equal or nearly equal1 no discharge will take place between them4 ,we may secure this by connecting all these bodies by means of good conductors1 such as copper-wire ropes2 but it is not necessary to do so2 for it may be shown by experiment that if every part of the surface surrounding a certain region is at the same potential1 every point within that region must be at the same potential1 provided no charged body is placed within the region4 ,it would therefore be sufficient to surround our powder-mill with a conducting material 7to sheathe its roofs1 walls1 and ground-floor with thick sheet-copper71 and then no electrical effect could occur within it on account of any thunderstorm outside4 ,there would be no need of any earth-connection4 ,we might even place a layer of asphalt between the copper floor and the ground1 so as to insulate the building4 ,if the mill were then struck with lightning1 it would remain charged for some time1 and a person standing on the ground outside and touching the wall might receive a shock2 but no electrical effect would be perceived inside1 even on the most delicate electrometer4 ,the potential of every thing inside1 with respect to the earth1 would be suddenly raised or lowered1 as the case might be2 but electric potential is not a physical condition1 but only a mathematical conception1 so that no physical effect could be perceived4 ,it is therefore not necessary to connect large masses of metal1 such as engines1 tanks1 c41 to the walls1 if they are entirely within the building4 ,if1 however1 any conductor1 such as a telegraph wire or a metallic supply-pipe for water or gas1 comes into the building from without1 the potential of this conductor may be different from that of the building1 unless it is connected with the conducting shell of the building4 ,hence the water or gas supply-pipes1 if any enter the building1 must be connected to the system of lightning-conductors2 and since to connect a telegraph-wire with the conductor would render the telegraph useless1 no telegraph from without should be allowed to enter a powder-mill1 though there may be electric-bells and other telegraph apparatus entirely within the building4 ,i have supposed the powder-mill to be entirely sheathed in thick sheet-copper4 ,this1 however1 is by no means necessary in order to prevent any sensible electric effect taking place within it1 supposing it struck by lightning4 ,it is quite sufficient to enclose the building with a network of good conducting substance4 ,for instance1 if a copper wire1 say ,no4 #d1 ,b4,w4,g4 7#jbch inch in diameter71 were carried round the foundation of a house1 up each of the corners and gables1 and along the ridges1 this would probably be a sufficient protection for an ordinary building against any thunderstorm in this climate4 ,the copper wire may be built into the wall to prevent theft1 but it should be connected to any outside metal1 such as lead or zinc on the roof1 and to metal rain-water pipes4 ,in the case of a powder-mill1 it might be advisable to make the network closer by carrying one or two additional wires over the roof and down the walls to the wire at the foundation4 ,if there are water- or gas-pipes which enter the building from without1 these must be connected with the system of conducting-wires2 but if there are no such metallic connections with distant points1 it is not necessary to take any pains to facilitate the escape of the electricity into the earth4 ,it is desirable1 however1 to provide for the safety not only of the building itself1 but of the system of conductors which protects it4 ,the only parts of this system which are in any danger are the points where the electricity enters and leaves it4 ,if1 therefore1 the system terminates above in a tall rod with a sharp point1 and downwards in an 8earth wire10 the external discharge will be almost certain to occur at the ends of these electrodes1 and the only possible damage will be the loss of a few particles from their extremities2 but even if the rod and wire were destroyed altogether1 the building would still be safe4 ,,on ,,boiler ,,and ,,factory ,,chimneys ,,and ,,lightning ,,conductors4 ,,by ,r4 ,,wilson4 #ahgg4 7,abstracted by ,prof4 ,t4 ,hayter ,lewis1 ,f4,s4,a47 ,the author refers to the wide-spread disbelief in the efficiency of conductors1 the common opinion being that metallic bodies1 especially when pointed1 attract lightning1 and are therefore dangerous4 ,this is quite erroneous4 8,on an electrified cloud passing over a pointed conductor1 the opposite and induced electricity of the earth is discharged from the point of the conductor1 and the cloud and air are often thereby neutralized without producing lightning at all4 ,but when a discharge does take place1 the conductor offers a line of comparatively small resistance40 ,the author further says that1 8if electrified clouds be driven to the erection in such masses that the opposite electricity does not stream away from the point of the conductor in sufficient quantities to prevent a spark from passing1 the spark or flash will pass from cloud to conductor in preference to any neighbouring point40 ,he refers to the safety of conductors1 as shown by ,sir ,w4 ,s4 ,harris's reports4 ,when injury to buildings has occurred where lightning rods are fixed1 they have been 8ignorantly and wrongly applied10 or joints have rusted1 the rods been broken1 or earth contact has become imperfect4 ,he refers to ,harris and ,faraday as to sectional area of conductor4 ,considers a rope to be better than a rod1 as it is less liable to be fractured and to have badly formed joints4 ,the upper extremity should project into the air as high as the diameter of the chimney top4 ,the rod should not be inside a chimney1 as gases are liable to injure it4 ,the conductor should communicate with all metal in the chimney4 ,insulation is not required4 ,all contact between copper and iron should be avoided on account of galvanic action4 ,earth contact should be tested every year4 ,anderson's galvanometer approved of for this4 ,,nouveau ,,paratonnerre ,,accept ,,par ,l',,acad,,mie ,,des ,,sciences4 ,,par ,,jarriant4 #hvo4 ,paris4 #ahgg4 7,abstracted by ,g4 ,j4 ,symons1 ,f4,r4,s47 ,this pamphlet is really a letter by ,m4 ,francisque ,michel respecting some new patterns of lightning conductors made by ,m4 ,jarriant1 and submitted to the ,acadmie des ,sciences by ,m4 le ,comte du ,moncel4 ,the author states that there have been many theories as to the advantage of conductors rising to great heights above buildings1 and that1 on the other hand1 some persons have urged that buildings should bristle all over with points1 and thus prevent any disruptive discharge4 ,he thinks that1 owing to the translation of the storm-cloud by the wind1 these short points will not always have time to act1 and says that the only rational plan is to place a conductor high above the house it is intended to protect1 and so constructed that it1 and it alone1 offers a path of scarcely appreciable resistance to the electric discharge4 ,he says that in ,germany they put a metal sphere on the top of the conductors1 but in ,france1 both the ,academy and the ,commission of the ,city of ,paris have advised that they should terminate in a point4 ,m4 ,francisque ,michel says that formerly a conductor was supposed to protect all objects within a cone whose base had a radius of twice the height of the conductor2 but that he and ,m4 ,flix ,lucas had investigated the question geometrically1 and have arrived at the conclusion that the radius cannot exceed #age of the height4 ,hence1 in many buildings1 it became necessary either to increase the number of the conductors or to make them more lofty1 both alternatives leading to increased expense4 ,m4 ,jarriant's design1 which consists of galvanized angle iron bolted together1 enables the increased elevation to be obtained at a price twenty per cent4 below that of the old patterns4 ,the angle irons themselves offer much surface1 their angles are useful for discharging electricity1 and they carry at the top the copper terminal recommended by the ,acadmie4 ,a ,,practical ,,treatise ,,on ,,lightning ,,conductors4 ,,by ,,henry ,w4 ,,spang4 ,philadelphia4 #ahgg4 7,abstracted by ,prof4 ,t4 ,hayter ,lewis1 ,f4,s4,a47 8,the identity of electricity1 manifested by friction1 with that contained in the atmosphere1 was not fully verified until ,franklin's experiment with his kite in ,june1 #ageb40 8,in restoring the equilibrium between the opposite electricities of high potential1 the discharge will pass by the shortest path1 even though a poor conductor1 in preference to a longer path through a good conductor40 ,the electricity of the earth is usually negative--of the atmosphere1 usually positive4 ,he quotes experiments at ,kew to this effect4 ,the friction of solid and liquid particles against the earth1 and against each other in the air1 produced by the wind1 is a source of atmospheric electricity4 ,the height of the lower part of the thunder-clouds above the sea in the ,united ,states averages about #b1ejj feet4 ,dense thunder-clouds are good conductors1 and are electrified to a certain extent by the induction of the electricity contained in the surface-earth4 ,as electricity accumulates in the thunder-clouds it acts by induction on the surface-earth1 and causes a corresponding increase of potential in the earth and the objects thereon4 ,he alludes to the vitreous tubes 7fulgurites71 #e feet to #ge feet deep1 as being formed by electricity passing to the subterranean water-bed through sand or other dry earth4 ,a highly positively electrified cloud within #c1jjj feet of a building causes the latter to be intensely negatively electrified by induction4 ,so also the earth beneath the building and the upper portion of the subterranean water bed4 ,whatever offers the least resistance to the stroke will be its chosen path and it will never leave a very good line of conductors1 which is in a short path between two opposite electricities1 for an inferior one4 #aea persons are killed by lightning annually in the ,united ,states1 ,france1 ,england1 and ,switzerland4 ,he quotes ,sir ,w4 ,s4 ,harris's system for the ,navy as preventive4 ,there is no absolute safety anywhere out of doors4 ,it can only be found inside a structure having good conductors1 with good earth connections4 ,conductors cannot prevent disruptive discharge4 ,they simply furnish a good path for lightning which passes over them without doing any damage4 ,protective ,area4--,a committee appointed in #ahge by the ,prefect of the ,seine reports as protected1 a circular space whose radius is equal to #ade ,should be #age1 see page 7#fg74 ,ed4 of height of conductor4 ,but this is not always to be relied upon4 ,it is necessary that a conductor extend along the ridge1 gable ends1 and eaves of a house1 and above each chimney4 ,lightning is electricity of very high potential1 and the difference of conductivity between the resistance of copper and iron to a lightning discharge is small and practically amounts to nothing4 ,iron rod conductors not to be less than #g_/af inch diameter4 ,no case is recorded where such a rod1 properly connected with the earth1 has been fused or greatly heated by lightning4 ,paint or an ordinary amount of rust does not affect conductivity4 ,a conductor of large surface exercises a much greater protective action than the same quantity of metal in the form of a wire or solid rod4 ,not because electricity in motion resides on the surface1 but that the expansive action of a discharge may have a wider scope through the metal4 ,so iron rain water-pipes are good conductors1 and should be connected with metal spouting1 conductor on ridge1 c4 ,cable conductors bend easily and can be made in one length1 so often answer better than bars4 ,if earth connection is good1 rusty joints are of little consequence4 ,conductors are not to be insulated4 ,iron pipes for gas1 water1 heating1 c41 also iron columns extending from basement to near the roof are to be connected with conductor and earth terminals4 ,the pipes on each side of gas meter are to be connected by iron bands4 ,air terminals are to rise about #d feet above each chimney or other elevated projection4 ,high steeples to have horizontal conductors round them at every #bj feet in height connected with vertical conductors4 ,one terminal in the centre of a building not over #be feet long or wide is sufficient1 or one at each end of the ridge4 ,one to each #bj feet of a large building1 with one at each end and to each chimney1 c4 ,when the horizontal portion of a lightning conductor1 or path along the roof of a building from ridge to eaves 7sic7 exceeds #ej feet in length1 the path becomes rather indirect for a lightning discharge1 which is then apt to select a shorter route through the building4 ,the upper part of terminal need not be gilt4 ,points are practically of no use4 ,chimneys are very likely to be struck1 owing to the heated air rising from them4 ,provide against this by metal caps4 ,there is danger also1 owing to the vapour rising from them1 from barns stored with new hay or grain1 stables1 schools1 churches1 c41 containing many people1 flocks of sheep1 c4 ,earth terminals must be in moist ground4 ,the author quotes ,prof4 ,f4 ,jenkin as to the difference of conductivity between well moistened and perfectly dry earth 7as porcelain1 c47 in electricity of low potential1 as #a1jjj1jjj1jjj1jjj to #a4 ,gas and water mains usually #d feet or so deep in dry earth1 therefore not good conductors4 ,examples quoted of injury to their joints by lightning1 which passed from conductors to the mains4 ,suggests1 as earth terminal1 an iron pipe1 #aj feet long1 #b inches diameter1 open at each end1 perforated at sides1 put in vertically1 and having the water from pipes for rain and waste led into it4 ,to be #h feet from foundation4 ,gives engravings of numerous forms proposed for conductors1 most of them being defective1 and none show improvement on ,franklin's round rod4 ,copper rods held by iron staples1 and connected with iron earth terminals1 are bad1 owing to galvanic action4 ,copper wires in cable conductors become brittle1 and snap when vibrated by the wind2 sometimes1 also1 they are eaten away by electrolytic action4 ,he gives a drawing of a house protected as suggested by him1 viz41 by metal rain water-pipes connected with the metal gutters and ridge2 also with his improved earth terminal by a good iron bar conductor4 ,gas1 water1 and other pipes are to be connected together1 and with conductor4 ,these often give better path for lightning than the conductors4 ,but dangerous if without proper earth terminal4 ,he disagrees with ,prof4 ,c4 ,maxwell's theory as to disconnecting the metal covering1 c41 of buildings from the earth4 ,lightning conductors detached from buildings do not afford absolute protection4 ,lightning has great affinity for gas-holders1 so one of the nearest guide columns should be connected by a metallic conductor with the pipe leading to street main1 and also with a vertical earth terminal4 ,when a telegraph line is altogether metallic1 well insulated upon poles1 c41 and not metallically connected with the earth1 the electricity of a storm-cloud will not exert so strong an inductive influence upon it as upon a line whose ends terminate in the earth4 ,line wire is often melted1 poles and apparatus shattered1 and employs sometimes killed4 ,as a remedy1 a galvanised iron wire is now fastened to every fourth pole by iron staples1 from #d inches above the top of the pole to a coil about #aj feet long of iron wire beneath its lower end4 ,,ueber ,,blitzableiter ,,und ,,blitzschl,,ge ,,in ,,geb,,ude ,,welche ,,mit ,,blitzableitern ,,versehen ,,waren4 ,,von ,g4 ,,karsten4 ,kiel4 #hvo4 #ahgg4 7,abstracted by ,r4 ,van der ,broek47 ,in this pamphlet ,dr4 ,karsten gives an account of two cases in which buildings that were provided with lightning conductors were damaged by lightning4 ,the author states that the statistics for the year #ahgc show that in ,schleswig-,holstein twenty-six per cent4 of all the cases of fire were caused by lightning2 #a_/acjth part of these cases occurred in the towns and the remainder in the country4 ,do lightning conductors guarantee absolute protection8 ,the author answers this question as follows3 ,there is no absolute certainty in empirical matters2 each new case may direct our attention to circumstances that had been overlooked4 ,if lightning conductors cannot be said to ensure perfect safety1 they certainly afford a very high degree of protection4 ,the flash of lightning which struck the church at ,garding1 on the #ahth of ,may1 #ahgg1 fractured the conductor in fifteen places and pierced the wall of the steeple in two places4 ,the inefficiency of the conductor resulted from the carelessness with which it was fixed2 the line was laid down the north side of the steeple and fastened with twenty-five wall eyes2 these wall eyes were hammered too deep into the wall1 thus damaging the line and forming a short and sharp bend in each case1 besides also unduly straining the wire4 ,the damage to the steeple was the consequence of a neglected secondary circuit4 ,there are an excessively large number of tie-rods in the steeple2 the heads of these rods are not connected together1 neither are they1 except in one case1 in close proximity to any of the larger masses of metal that are about the building4 ,the conductor passed close to one of those heads2 the south side of the steeple1 where the opposite head is1 becoming wet through the rain1 a secondary circuit was formed1 and a return shock followed2 the damage to the steeple was trifling4 ,the rod was provided with a conical point rather blunt but surmounted by a short platinum point4 ,the copper line-wire was of good material--not of a uniform thickness1 but at the weakest places not weighing less than #bdj grammes per lineal metre 7#h oz4 per yard or rather less than inch diameter if solid74 ,the earth-plate was sunk into a well #aj metres deep1 and tested faultless after the discharge4 ,,tude ,,sur ,,les ,,paratonnerres ,,leur ,,construction ,,leur ,,installation4 ,,par ,,jarriant4 #hvo4 ,paris4 #ahgh4 7,abstracted by ,g4 ,j4 ,symons1 ,f4,r4,s47 ,this pamphlet opens with two pages devoted to the consideration of ,michalis's work published in #aghc1 8,de l'effet des pointes places sur le ,templ de ,salomon20 then it becomes more practical1 refers to the ,academy of ,bordeaux propounding in #agej the question as to the identity of lightning and electricity1 and to ,franklin's letter in the same year to ,collinson1 giving his reasons for believing in the analogy2 states that the experiments suggested by him were repeated by ,buffon and ,dalibar in ,march1 #ageb1 and subsequently repeated at ,marly before ,louis ,,xv4 ,then the writer refers to the erection of the first conductor in ,france1 to the popular displeasure which it excited1 and to the long legal process before the proprietor was allowed to keep it in position4 ,the author thinks that in many cases it is better to slightly increase the number of conductors than to make them of excessive length1 because the latter course causes them to fatigue and jar the roof timbers by their vibration with the wind4 ,respecting platinum points he speaks strongly and to the following effect3--8,i have already mentioned that ,franklin's first conductor was melted4 ,since then1 the upper terminals of conductors have been made of platinum1 because it is the least fusible1 the least oxidizable of all metals1 and a very suitable one for making into points4 ,moreover1 the sharper a point the greater its preventive action1 and hence ,i condemn every conductor without a platinum point4 ,although some manufacturers employ simple copper cones1 which may certainly last some time without deterioration1 believing in the desirability of the points being always in perfect order1 ,i reject their system entirely40 ,few persons are used to making platinum points1 it is a ,parisian speciality1 those which the author prefers1 form a cone of about #aj degrees at the opening of the point and are about #a inches long1 then screwed and soldered into a mass of copper forming a nut on the conical copper rod1 which is #a foot or #a foot #f inches long4 ,the platinum point thus mounted can only give rise to a galvanic action so extremely feeble as not in the least to affect the durability of the apparatus4 ,some persons for the sake of cheapness suppress this platinum point1 but they are wrong1 the saving is slight and the result defective4 ,the author objects to conductors made of bar iron because the joints are always defective1 and if the section be too small they may be so heated as to set fire to the charcoal in which the lower extremity is buried4767 ,however1 the author prefers a rope1 but he does not say whether of iron or copper1 and he puts a strand of hemp in the middle so as to make it more pliable4 8,arrived at the ground the conductor ought not to be in immediate contact with the earth1 for the damp would slowly destroy it2 we avoid this 787 by making it pass through a trough filled with coke4 ,experience has shown that iron thus buried in coke undergoes no change even during thirty years4444 ,broken coke is better than charcoal because of the great quantity of water which it absorbs40 ,the author then says that after passing through this trough the conductor must be continued into a well1 or into very moist earth1 and should end with a discharger like a fork with many prongs4 ,he recommends that all the iron be galvanized4 ,although the concluding paragraph1 coming from a manufacturer1 sounds rather like self-recommendation1 it undoubtedly contains important truths4 ,m4 ,jarriant says3-- 8,i cannot too strongly advise that in erecting conductors those specialists should be employed1 whose studies and constant practice enable them to ensure perfect work4 ,it is necessary also that every workman should remember that in placing a lightning conductor he holds in his hands the lives of men1 that he should feel conscientiously interested in the perfection of his work1 and1 finally1 that he should feel that it is a mission which he fulfils1 and not a mere matter of trade at which he works40 ,,report ,,on ,,the ,,lightning ,,conductors ,,of ,,the ,,small ,,arms ,,ammunition ,,factory ,,at ,,dum ,,dum1 ,,calcutta4 ,,by ,w4 ,p4 ,,johnston4 ,government ,telegraph ,press4 #ahgh4 #dto4 7,abstracted by ,w4 ,h4 ,preece1 ,c4,e47 ,this is an interesting report of a careful inspection and an electrical testing1 by a skilled electrician1 of the lightning conductors at this place4 ,although most carefully protected by well arranged and adequate copper rods1 copper bands1 iron rods1 and iron tubes1 and terminated in points1 it was found that the points were covered either with rust or with paint1 and that the earth connections were so bad as to render the buildings unsafe1 although there was no difficulty in obtaining a good earth at any part of the factory4 ,,atmospheric ,,electricity4 ,,by ,,david ,,brooks4 ,philadelphia4 #ahgh4 #hvo4 7,abstracted by ,w4 ,h4 ,preece1 ,c4,e47 ,a pamphlet by a distinguished ,american telegraph engineer1 giving his view on the magnitude and origin of atmospheric electricity1 which he attributes principally to the friction of air on ice in the ,polar regions1 and which circulates southwards in the higher regions of the air1 and northwards in the crust of the earth4 ,hence also ,aurora ,borealis which is always preceded by high winds and most frequent when the earth is covered with snow4 ,thunderclouds are usually about #b miles high and from #ac to #bc miles thick4 ,lightning is much less frequent in mountainous than in plain countries4 ,copper lightning conductors are often applied to iron ships and iron buildings1 but absurdly1 as they are in such cases superfluous4 ,the author advocates immense earth plates where there are no gas- and water-pipes1 which he calls the best lightning rods ever erected1 because they are electrically in perfect connection with the earth4 ,the track of a railway makes a capital earth4 ,he has never known an accident where proper conductors were used1 whereas he has known many accidents from imperfectly and improperly constructed lightning rods1 though of the latest and most approved patents4 ,,catalogue ,,messrs4 ,a4 ,,collin ,,et ,,fils1 ,article ,,paratonnerres4 ,paris4 #dto4 7,abstracted by ,prof4 ,t4 ,hayter ,lewis1 ,f4,s4,a47 ,the authors state that a ,municipal ,commission has recommended1 to the exclusion of all other points1 copper about inch diameter1 terminating in a cone of #cj4 ,as to the area protected ,messrs4 ,collin refer to the reports of the ,academy in #ahbc and #ahed1 admitting1 as a limit of protected area1 a circumference of which the radius equals double the height of the upper terminal for slightly elevated buildings1 and simply the height for towers1 c41 but this rule is badly defined4 ,the authors quote formul based upon the assumed altitude of the storm cloud1 but state them to be unreliable4 ,the ,academy in #ahed reports that an electrified cloud is equally attracted at equal distances by a metallic part of the roof and by the terminal of the conductor4 ,exposed points of pinnacles1 c41 are to be united to main conductors4 ,if copper be too expensive use iron wire4 ,the conductors are to be supported at about #aj centimetres 7#d ins47 from walls and roofs4 ,the ,academy recommends them to be isolated on glass or porcelain1 but the ,new ,commission rejects this1 and suggests that all metallic parts be united to the conductor1--also recommends that wells be sunk to water level1 as earth connections4 ,but this would often entail a depth of #bj to #ajj metres1 or even more4 ,so the conductors may be sunk into moist earth and surrounded with coke1 and if necessary1 may terminate in a sheet of copper4 ,a good earth is very important4 ,connection with water mains advised4 ,the authors have fixed #h1jjj lightning conductors on their principle without failure4 ,they give engravings of the various parts4 ,they engrave a diagram of a powder magazine which they propose to protect by a tall isolated lightning conductor fixed at a distance from it1 and at such a height as that it will be included in a cone whose radius is equal to the height of the conductor4 ,,the ,,scientific ,,american1 ,,november #ast1 #ahgi4 7,abstracted by ,alfred ,j4 ,frost47 ,we learn that a lightning rod company in ,cincinatti has patented a system of lightning protection1 which consists of an iron rod running along the ridge of the building with points at each end projecting upwards4 ,it is supported upon large glass insulators1 and has no electrical connection with the building1 and no rod running to the ground4 ,it is said that there are many public buildings in ,iowa which have been provided with this system of lightning rods4 ,professor ,macomber1 of the ,iowa ,agricultural ,college1 in reply to an inquiry1 says that it would be possible that a house insulated with a glass foundation could be struck by lightning1 but adds1 8,by insulating a building the tendency to be struck by lightning would be very much lessened1 and the severity of the shock much decreased4 ,practical illustrations of this can easily be obtained by means of an electrical machine4 ,a spark can be made to pass from the machine to an insulated body1 although the force of the shock will be much less than when not insulated4 ,practically1 it would be almost impossible to insulate a building1 because after rain commenced to fall it would wet it so that communication with the earth would be established40 ,,remarks ,,on ,,the ,,atmospheric ,,electricity ,,and ,,on ,,the ,,action ,,of ,,lightning ,,conductors4 ,,by ,,prof4 ,,dr4 ,g4 ,,karsten4 #bnd edition4 ,kiel1 #ahgi4 7,abstracted by ,h4 ,van der ,broek47 ,the author of this pamphlet1 ,prof4 ,dr4 ,g4 ,karsten1 states that thunderstorms are particularly dangerous in ,schleswig-,holstein4 ,he attributes that fact to the scarcity of woods in that province1 not more than five per cent4 of the surface being wooded2 whilst in the ,prussian empire the proportion of woods is twenty-three per cent4 ,woods promote a uniform dampness of the atmosphere and lessen the up-current of air1 which up-current contributes considerably to the formation of thunderstorms2 and the woods thus cause the discharges of the electricity to take place principally between the clouds4 ,we do not yet know with certainty what the causes of atmospheric electricity are1 but we do know under what conditions or circumstances thunderstorms may occur4 ,thunderstorms are only formed when a violent condensation of the rarified particles of water1 which the atmosphere contains1 takes place4 ,such a sudden condensation1 and the consequent formation of a thunderstorm1 may occur when two different masses of air--the one moist and warm1 the other dry and cold--intermix rapidly4 ,the former of these currents we call the ,south1 or ,equatorial current1 the latter the ,north1 or ,polar current4 ,if these currents penetrate each other1 or intermix slowly1 long continued falls of snow and rain ensue2 if they mix rapidly thunderstorms are formed during the warmer seasons1 and sometimes also during the colder seasons4 ,the ,schleswig-,holstein ,provincial ,fire ,insurance ,association alone paid1 in sixteen years1 the sum of #ajb1hcb 7an average of #f1dbg7 for damages caused by lightning4 ,this province loses altogether #ab1ejj per annum through fires caused by lightning4 ,the author's very interesting remarks on the construction of lightning conductors are briefly summarised in the following general rules3 #a4 ,copper and iron form the best materials for lightning conductors2 lead and zinc may be used for secondary conductors4 7,nebenleitungen47 #b4 ,if the conductor be constructed of iron1 it should weigh from #a1bjj to #c1djj grammes per metre 7#b lbs4 to #g lbs4 per yard71 according to its length2 a copper conductor should weigh1 under the same circumstances1 from #bej to #fjj grammes per metre 7 lb4 to #a lbs4 per yard74 #c4 ,the conductor must be connected with all the projecting corners and pointed parts of the building4 #d4 ,there must be no sharp curves or bends in the conductor4 #e4 ,the conductor must be connected with all the large and extensive masses of metal that may be about the building4 ,this connection may be made by wires leading towards the rod1 as well as in the direction of the earth contact4 #f4 ,the rods must be surmounted by good points1 which must not be liable to be fused by the discharges of the electricity4 #g4 ,the height of the rods must be in proportion to the size and shape of the buildings2 but it is better to erect several short rods than one extraordinarily long one4 #h4 ,in making the connection with the earth all sharp curves must be avoided4 #i4 ,the underground part of the conductor must be made of galvanized metal1 so as to minimise the effects of oxidation1 or1 in case a layer of coke is used1 to prevent the action of the sulphur4 #aj4 ,the earth-contact should terminate in a plate1 which1 if possible1 should always be immersed in water4 ,if this can be so arranged the plate must have a surface th of a square metre 7#a foot square7 for conductors for small buildings1 whilst a plate of a surface of #b square metres 7#e feet square7 will be sufficient for conductors for the largest buildings4 #aa4 ,where a permanent contact with water cannot be established1 several plates of a larger size must be used1 and laid in a stratum of coke4 #ab4 ,in the case of very large buildings1 provided with several rods and secondary conductors1 several earth-contacts should be made which should be connected with each other4 ,with reference to the upper terminal point1 the author remarks1 in an appendix to the second edition of his pamphlet1 that it should be made of a conical form of a basis of from #bj to #cj millimetres 7#jh in4 to #ab in471 and of a length of #aej millimetres 7#f inches72 it must consist of pure copper and be gilded4 ,it is useful to provide it with a platinum needle #ae millimetres 7half an inch7 long1 and about #d millimetres 7#jb inch7 thick at its base2 or with a cone of chemically pure silver1 the proportion between whose base and height must be as #b 3 #c4 ,,lightning ,,conductors4 ,,by ,,richard ,,anderson1 ,london1 #ahgi4 7,abstracted by ,prof4 ,t4 ,hayter ,lewis1 ,f4,s4,a47 ,historical ,facts-- ,the following are brief references to some of the principal facts recorded in this volume3-- #afjj ,a4,d4 ,dr4 ,gilbert showed that magnetic and electrical phenomena were emanations of one force4 #afej4 ,otto ,von ,guericke constructed a little electrical machine 7mainly of a ball of sulphur on a revolving axis74 ,sir ,i4 ,newton constructed a machine of glass1 but used it merely for amusement4 #afge4 ,the polarity of a ship's compass was found to be reversed by a stroke of lightning4 #agjh4 ,dr4 ,wall said that the light and crackling of rubbed amber seemed in some degree to resemble lightning and thunder4 #agji4 ,f4 ,hauksbee1 ,f4,r4,s41 showed the similarity between the electric flash and lightning4 #agbj4 ,s4 ,gray1 ,f4,r4,s41 showed this by experiment1 but was discredited4 #agde4 ,the first great step in this science was made at ,leyden1 by ,j4 ,n4 ,allamand and ,p4 van ,musschenbroek1 who discovered the properties of the ,leyden jar4 ,the priority of this invention disputed by ,dr4 ,winckler1 of ,leipzig2 a mania for experiments arose4 ,louis ,,xv4 tried them1 unsuccessfully1 on #ahj of his ,guards2 but with perfect success on #gjj ,carthusian ,monks4 #agdf4 ,dr4 ,franklin1 of ,philadelphia1 saw some electrical experiments1 and in #agdg received a glass tube and some books on electricity from ,london2 then began to make experiments2 sold his business1 bought apparatus and made electricity his study4 ,discovered that electricity passed most easily and quickly through sharply pointed metals2 that it was positive and negative2 and that lightning and electricity were identical4 ,he sent these results to the ,royal ,society1 who refused to allow them to appear in their ,transactions2 he then published them in a pamphlet4 ,it was not appreciated in ,england1 but met with great applause in ,france1 and was also translated into ,german1 ,italian and ,latin4 #agdg4 ,the subject was taken up in ,england in a thoroughly practical manner4 ,dr4 ,watson1 ,mr4 ,folkes1 ,lord ,c4 ,cavendish1 ,dr4 ,bevis1 c41 experimented on a wire stretched across the ,thames4 ,the charge was found to come back by the water4 ,the same result followed through moist earth4 ,a gun was fired at a distance of four miles2 the passage of the charge appearing to be instantaneous4 ,new experiments were made by ,dr4 ,watson with glass rods1 #b and #c feet long and #a inch diameter4 ,these showed that the rods1 c41 contained electricity only as a sponge holds water4 #ageb4 ,experiments by ,messrs4 ,dalibard and ,de ,lor1 at ,marly-la-,ville1 near ,paris1 in ,may1 described4 #ageb4 ,july4 ,franklin tried his ,kite successfully1 then his fame was established1 and he erected1 on his own house1 the first lightning rod4 #agec4 ,prof4 ,richmann1 ,st4 ,petersburg1 was killed whilst experimenting4 ,the use of conductors opposed1 violently in ,france1 by ,abb ,nollet4 #agee4 ,an earthquake at ,massachusets1 was laid to the charge of the numerous lightning conductors4 ,franklin pushed their use by means of his publication1 8,poor ,richard10 which had an enormous circulation2 particulars given showing success of lightning conductors4 #agfb4 ,the first lightning conductor used in ,england1 and ,dr4 ,watson asked to send in designs for lightning rods for ships4 ,he did so1 but in an unpractical way1 and they were disused4 #agfd4 ,st4 ,bride's steeple struck4 #agfi4 ,the ,dean and ,chapter asked ,royal ,society for advice as to protecting ,st4 ,paul's4 ,committee of ,royal ,society disagreed as to whether rods should be pointed4 ,pointed rods were used4 #agfi4 ,the first conductor fixed to a public building in ,europe was to a church steeple in ,hamburg4 ,de ,saussure1 at ,geneva1 had some difficulty in explaining to the citizens that his conductors were not dangerous to his neighbours4 ,there was a great fear1 generally1 as to their use1 e4g41 a lightning rod was erected1 secretly1 by the ,priests at the ,cathedral of ,siena1 and excited great terror in the townsmen when discovered1 but a terrific stroke of lightning left the tower uninjured4 #aggb4 ,dr4 ,ingenhousz's experiments4 #aggd4 ,the ,university of ,padua protected by conductors4 #aggg4 ,a building at ,purfleet was struck though it had a conductor1 but this was shown to be defective4 ,sir ,j4 ,pringle had to resign his ,presidency of the ,royal ,society because he advocated points1 but experiments were made and ended in favour of points4 #aggh4 ,the ,venetians decreed that lightning rods should be erected throughout the ,republic4 #ahai4 ,electro-magnetism discovered by rsted4 #ahbb4 ,sir ,w4 ,s4 ,harris took up the question of providing good conductors for ships1 and afterwards made a list of #bej accidents to ships in #dj years2 also of #bjj seamen killed or wounded in that time4 ,at this time no importance was attached to the subject in ,england1 except in the case of ,sir ,w4 ,s4 ,harris4 ,he insisted on the necessity of lightning rods4 ,a commission of inquiry was appointed by ,h4,m4 ,government to investigate the best method of applying lightning rods to ,h4,m4's ships1 and they reported 7in #hj pages folio7 that lightning rods were rather new fangled things1 but might be tried1 without special harm to anybody4 ,so most ships were fitted with them after ,sir ,w4 ,s4 ,harris's design4 ,he was knighted in #ahdg4 ,an iron built ship1 metal rigged1 is as well protected from lightning as ,solomon's ,temple4 ,harris combated the opinion of those who said that lightning rods attracted lightning4 ,even in #ahbf a government engineer recommended1 on this ground1 that all lightning rods should be pulled down1 and1 in #ahch1 the ,governor-,general of ,india ordered this by the advice of his 8scientific officers40 ,this was not countermanded until several buildings had been destroyed4 ,army circulars are now regularly issued1 containing ,sir ,w4 ,s4 ,harris's suggestions4 7,these quoted by ,mr4 ,anderson74 ,sir ,c4 ,barry suggested that ,sir ,w4 ,s4 ,harris should design lightning conductors for new ,houses of ,parliament4 ,he reported in #ahee4 ,he used conductors of #b inch copper tubes1 th-inch thick1 to towers and other elevated parts1 secured to masonry by metal staples4 ,the cost was #b1cad4 ,as to conductors1 ,le ,roy recommended that they should rise not less than #ae feet above chimney and summit of any edifice4 ,mr4 ,anderson gives technical names of parts of lightning rods in different countries4 ,chains first used1 and gave rise to many accidents4 ,tin and lead conductors tried2 lead especially1 from its easy application to sharp curves1 c41 but it is liable to be broken1 and is a bad conductor2 so it went out of use4 ,some particular buildings are constantly under attack from lightning1 e4g41 ,church of ,rosenberg in ,carinthia1 not standing in a very high position1 but greviously damaged in #agcj1 c42 rebuilt in #aggh1 with lightning rod1 and not injured since4 ,some of these effects may be explained on meteorological grounds3 the height and thickness of the charged clouds only slightly varying1 perhaps1 in districts where there are prevailing winds4 ,the height of clouds sometimes enormous4 ,instances are given of their being #ae1jjj to #be1jjj feet above the sea4 ,but sometimes clouds are almost flat on the earth1 two instances are given of this4 ,a remarkable and often fatal discharge is the 8return stroke10 always less violent than the direct stroke1 but often very powerful1 and caused by the inductive action exerted by a thunder-cloud4 ,men and animals are charged with opposite electricity to the cloud4 ,when the latter is discharged by the recombination of its electricity with that of the ground1 the induction ceases1 and all bodies charged by induction return to a neutral condition4 ,hence the dangerous 8return stroke40 ,lord ,mahon first demonstrated this by experiment4 ,as to origin of atmospheric electricity1 ,de ,saussure considered it due to the evaporation of water by the sun's heat4 ,peltier 7#agfe-ahde7 considered the earth itself to be one immense reservoir of electricity4 ,as light comes from the sun1 so electricity is generated by heat from the interior of the globe4 ,no electricity is produced by atmosphere1 nor held by it1 except temporarily4 ,there is no recorded case in which a well made lightning rod1 with 8good earth10 did not do its duty4 ,in #ahbb there was an extraordinary number of thunder storms in ,france1 so lightning rods were ordered by ,minister of ,interior for all public buildings1 and he applied to the ,academy of ,sciences for advice4 #ahbc4 ,a ,committee 7,gray ,lussac1 c47 reported4 ,they laid it down1 as a rule1 that a lightning rod protected a circular area1 having a radius of double the height of the rod2 and they said nothing about regular inspection of lightning rods4 ,so disasters occurred1 and another ,committee was appointed 7,pouillet1 c474 ,they reported #ahed4 ,the theory as to the protected area was abandoned4 ,it was recommended that lightning rods should have as few joints as possible4 ,the joints to be well soldered1 the points to be of copper 7not platinum71 and not to be very finely pointed4 ,the rods to be of copper1 not iron4 ,the ,louvre was well protected by lightning rods1 but slightly injured1 #ahed4 ,another ,committee was appointed1 and1 #ahee1 ,pouillet again reported on its behalf4 ,it recommended that the points 7always of copper7 should be thicker1 and the rod to have a never-failing connection with water or moist earth1 #ahff4 ,several ,french powder magazines were struck though provided with lightning rods1 and the ,minister of ,war asked the ,academy for another report4 ,another ,committee 7,becquerel1 c47 was appointed1 and1 #ahfg1 ,pouillet again reported4 ,he defines lightning as an immense electric spark passing from one cloud to another1 or from cloud to earth1 to restore equilibrium4 ,the best protection for a building would be iron rods surrounding it on all sides1 and passing deep into ground4 ,conductors should be inspected every year4 ,the conductor now remains essentially as ,franklin invented it4 ,of the inner nature of 8lightning0 we are utterly ignorant4 ,the first conductors were always of iron as being cheap4 ,sir ,h4 ,davy pointed out the different conducting powers of different metals4 ,becquerel1 ,lenz1 ,ohm1 and ,pouillet made similar investigations1 with the following results3-- ,silver4 ,copper4 ,lead4 ,tin4 ,iron4 ,iron #a ,copper ,davy #ajia #ajj #fia #adf #fhe ,becquerel #gce #ajj #hc #aee #aeh #fcc ,lenz #acfbe #ajj #adfb #cjhd #aggd #efd ,ohm #cefj #ajj #ig #afh #agd #ege ,pouillet #habf #ajj #ahb to #edi to #aef #fda 7,the difference being owing1 probably1 to the greater or less purity of the ,metals47 #ahae4 ,brass wire rope generally used in ,bavaria1 but a steeple was struck down though with a brass wire conductor #a inch diameter4 ,the real defect was 8bad earth10 but attributed to bad form of conductor2 so this was abandoned4 ,brass not a reliable metal1 and often destroyed by smoke4 ,purity of copper essential4 ,professor ,matthiessens' experiments shewed that the conductivity of copper varied from-- ,pure #ajj to ,australian #hhhf ,russian #eicd and ,spanish1 ,rio ,tinto #adbd ,hotel de ,ville1 ,brussels1 lightning rods designed by ,professor ,melsens on the principle of a great number of small ones in preference to one of large size1 and covering building with network of metal1 having many points and many earth contacts4 ,he considers that the relation of section to surface of the lightning rod has a marked and definite1 though unknown1 result4 ,author describes weathercocks and methods of fixing them4 ,lightning rods generally--methods used in ,france3 ,terminal rods1 usually of wrought iron1 galvanized2 their height depends on the size and area of building it protects4 ,this is generally to be considered to be within a cone of revolution1 of which the radius height of rod above ridge #age4 ,points described4 ,the conductors are of iron1 rebated1 soldered1 and bolted at joints1 with lead between4 ,bent plates of copper introduced to provide against contraction and expansion4 ,in large buildings1 metallic connections are formed on ridge by iron bars- in4 in4 ,precautions are taken against the destruction of iron underground1 viz41 by enclosing it in vertical sprints of wood1 tarred or creosoted1 rising a few inches above ground1 or by a coating of tar or by a wrapper of sheet lead4 ,the earth connection is a trough filled with broken charcoal1 through which the conductor passes1 ending in several branches1 or in a grating between layers of charcoal4 ,galvanized iron cables sometimes used1 and 7rarely7 copper of in4 diameter4 ,america4 ,gutters and water pipes1 c41 used where possible4 ,if the roof be of wood1 slate1 c41 a conductor is laid along ridge1 and connected with gutters and rain water pipes4 ,if these latter be less than #c in4 diameter1 the conductor is often extended from roof down the side of building close to the pipe4 ,all metal chimney caps1 railings1 water and gas pipes1 and other large or long pieces of metal1 inside and out1 are connected with conductor4 ,the upper terminal usually projects #d ft4 above chimney or other highest part of building4 ,it is a round rod1 #g_/afth in4 diameter1 hammered out to join it to conductor4 ,a building #be ft4 wide and broad has one terminal in centre and one at each end4 ,in larger buildings1 one terminal to each #bj ft4 of roof4 ,not always pointed4 ,steeples have horizontal conductors at every #bj feet1 connected with vertical conductors1 to provide against discharge in centre1 caused by deflection of discharge in the air by rain4 ,conductors are fixed to buildings by iron staples or straps2 the earth connections are similar to ours4 ,also are used iron pipes1 about #c in4 diameter and #aj ft4 long1 placed vertically in moist earth and carefully connected with conductor4 ,newall's system3 ,copper conductors are the best1 and in the end1 cheapest4 ,terminal rods are usually #c to #e ft4 long1 and th to in4 diameter1 branching out at top4 ,german 8reception rod0 described as being of iron1 #aj to #cj ft4 long2 the area of protection theory discredited4 ,the electric fire1 seeking its nearest path to earth1 is not to be diverged from it to the rod4 ,these high rods of no use except1 e4g41 near high trees1 and are often dangerous from being blown down4 ,barns containing new hay are likely to be struck1 as hay sends out stream of warm air4 ,designs explained for protecting private houses by short terminal points to chimneys1 gables1 c4 ,a copper rope at least th in4 diameter should be used2 a copper rod1 in4 diameter1 has never been fused1 so far as is known4 ,in chimneys of manufactories1 where rope is liable to corrosion1 a greater thickness should be used4 ,laughton-en-le-,morthen steeple injured1 though with lightning rod1 but this was only a small1 thin copper tube1 th in4 external diameter1 and #a_/cb in4 thick2 weighing #hoz4 per foot1 or equal to a rod about #jab in4 diameter1 the joints were corroded1 and the earth contact was imperfect4 ,nevertheless1 only one buttress was injured4 ,it is of little consequence whether the conductor be inside or outside1 if it be carried to earth by the shortest route4 ,at first it was more generally put inside in ,france1 but this was given up for fear of accidents4 ,but it is beyond controversy that a good conductor is absolutely harmless to all surrounding objects1 and a man might lean against a copper half-inch rod1 carrying off a heavy stroke of lightning into 8good earth10 without being aware of its passing4 ,it is useless and dangerous to isolate conductors from buildings4 ,all masses of metal should be connected with conductors4 ,prof4 ,clerk ,maxwell's theory described 7as to disconnecting the conductors1 c41 from the earth73 ,he states that it is not necessary to connect masses of metal1 as engine tanks1 c41 if entirely within the building1 unless a conductor as1 e4g41 telegraph wire1 water or gas pipe come into the building from outside1 then they must be connected with conductor4 ,list of accidents from lightning1 also deaths or injuries in ,england and ,wales1 ,prussia1 ,united ,states1 ,sweden and ,austria4 ,particulars of damage to ,st4 ,george's ,church1 ,leicester1 #ahdf1 and to ,west-end ,church1 ,southampton4 ,also1 to ,merton ,college1 ,oxford1 and ,st4 ,bride's ,church1 ,fleet ,street1 none of these having lightning rods4 ,wrexham ,church struck1 this had a copper conductor1 but it was too small and the earth contact was doubtful4 ,list of buildings struck at home and abroad from #aehi to ,september1 #ahgi1 the authorities for the statements being given4 ,list of powder magazines struck between #agcb and #ahgh4 ,earth ,connections4 ,franklin's report1 #aggb1 strongly urges the importance of this1 in speaking of the powder magazine at ,purfleet4 ,in ordinary cases1 moist earth is sufficient1 but in such a case as this he recommends that a well should be dug at each end of magazine1 with #c to #d ft4 of water in it4 ,the importance of 8good earth0 is shewn by numerous accidents to buildings1 as1 e4g41 in #aggi1 the church of ,st4 ,mary1 ,genoa1 and1 in #ahgb1 the cathedral of ,alatri1 in which latter case1 the discharge left moist earth to pass off by a water pipe1 which it broke2 but the church was uninjured4 ,also at ,clevedon ,church1 where the conductor passed into a drain which was dry1 but the stroke merely injured one buttress and passed off by gas and water pipes4 ,mr4 ,anderson states that earth contacts must be large4 ,that it is important that metal work be connected with lightning rod in at least two parts1 to realize a closed metallic circuit1 and so offer entry and exit4 ,the earth contacts of the eight conductors of the ,hotel de ,ville1 ,brussels1 described1 viz41 their being enclosed in an iron box1 #h in4 #c in4 #c in41 with three series of conductors 7details given73 one passing into a well1 another to the gas main1 the third to water main4 ,in ordinary buildings1 the grating1 with charcoal1 coke1 or cinders1 c41 as before described1 may be sufficient2 but with large buildings1 contact with water is absolutely necessary4 ,periodical inspection4 ,author strongly urges this because conductors deteriorate from action of wind and weather above ground2 the 8earth0 often becomes bad1 owing to new drains1 c42 buildings may be altered in regard of the quantity and position of metals4 ,an instance is given of damage to a building owing to the change of position of iron safe4 ,conductors are often displaced by workmen2 and the number and position of new gas and water mains1 new trees1 c41 also influence the power of conductors4 ,appendix4 ,this contains a very full list of books relating to lightning conductors4 ,,report ,,upon ,,lightning ,,discharges ,,in ,,the ,,province ,,of ,,schleswig-,,holstein4 ,,by ,,dr4 ,,leonhard ,,weber4 #ahhj4 #hvo4 7,abstracted by ,alexander ,siemens74 ,the serious damage caused in ,schleswig-,holstein by lightning led to an official inquiry into the subject1 the following is an abstract of the first report of the commission4 ,it is stated that trees1 by their gradual but uninterrupted discharge of electricity1 have a dispersing effect upon thunder-clouds1 and tend to lessen the energy of lightning4 ,in six cases out of the twelve examined1 houses with trees close by1 were struck1 but not so heavily as in another case where the building had no protection whatever4 ,trees do not1 however1 afford complete protection to neighbouring buildings1 their conductive capacities not being sufficient to convey1 in the immeasurably short time required1 such heavy discharges of electricity as lightning flashes4 ,this is instanced by their being often wholly1 or partially1 destroyed by the current1 or1 as occurred in four cases1 by their passing it over to better conductors1 buildings1 c4 ,if a thunder-cloud passed over a perfectly plane surface1 the discharge would take place in a vertical line between earth and cloud1 but prominent objects1 such as isolated trees1 buildings1 lightning conductors1 and iron pumps1 reaching down to underground water1 act as attractive points1 and divert the discharge1 the path of which is also influenced by any conductors which happen to come between them and the thunder-cloud1 such influence depending upon the capacity of the conductors4 ,so that1 generally an electric discharge chooses that path which1 taking the distance into account1 offers the best means of conduction4 ,it is frequently found that inflammable material is struck by lightning without being ignited1 on account1 it is presumed1 of the short duration of discharge not allowing the material to become sufficiently hot to burn1 but whether the duration of discharge is dependent upon the nature of the charge of the thunder-cloud1 or solely upon the condition of the objects struck1 has not been ascertained4 ,the latter is1 however1 not without influence1 as in two of the four cases which resulted in fire1 the cause was presumably due to newly gathered hay stored at the top of the houses struck1 and in the other two cases to trees1 which were struck at the same time1 the hay and the trees being bad conductors1 and prolonging the duration of discharge4 ,four cases are given of buildings having lightning conductors being struck4 ,the first case is that of a windmill1 the conductor of which terminated in a sheet of metal placed in a well near the building4 ,the discharge was exceedingly heavy1 but beyond the platinum point being almost entirely fused1 no other damage was done4 ,the second is that of a house with two separate lightning conductors1 each ending in a copper plate1 spirally coiled up1 and laid in underground water4 ,one of the conductors was struck1 and the lightning passed from it1 and1 running horizontally along the thatched roof of the house1 descended by the other1 causing no damage4 ,the third case refers to a church and1 adjoining it1 a school building4 ,a portion of the discharge was diverted from the conductor by an anchor in the church wall three metres off 7which it magnetized71 and forced its way through the ceiling of the school-house to a number of gas brackets1 which were turned up towards the ceiling4 ,it was ascertained that the ground floor of the house was completely under water1 and well connected to earth through the gas mains and an iron pump1 a good continuous conductor thus being formed4 ,accordingly1 the report recommends that lightning conductors should be connected to the large masses of metal1 such as gas and water mains1 which are found in our houses4 ,in the fourth instance a church had a lightning conductor1 which was connected to the top of two large iron supports running through the steeple to the nave1 and which terminated in a coiled earth-plate1 #a sq4 metre 7#aa sq4 ft471 supposed to lie in water #g metres 7#bc ft47 underground4 ,the lightning struck the conductor and1 passing to the iron supports1 sprang from one through the outer wall1 close to an iron window frame1 and from the other across the stucco ceiling1 going to earth #ajj feet off through the altar gilding1 which it blackened4 ,it was subsequently found that the copper earth-plate was only metre 7#a ft4 #a in4 sq471 and that it was buried loosely round the rod in dry sand1 the rod itself reaching #b to #c metres further down1 and just touching water without an earth-plate1 and also that the two supports had no earth connection1 thus forming a great danger instead of a safeguard to the church4 ,,die ,,konstruktion ,,und ,,anlegung ,,der ,,blitzableiter ,,zum ,,schutze ,,aller ,,arten ,,von ,,geb,,uden ,,seeschiffen ,,und ,,telegrafen ,,stationen4 ,,von ,,dr4 ,,otto ,,buchner4 ,weimar4 #ahfg4 #hvo4 7,abstracted by ,r4 ,van der ,broek47 ,the book is divided into two parts3 #a4 ,general1 or ,introductory1 and #b4 ,practical4 ,the first1 or ,introductory part1 is sub-divided into3 #a4 ,historical and statistical notes2 #b4 ,the theory of atmospheric electricity1 and of the lightning conductor2 and #c4 ,a chapter on natural lightning conductors4 ,the great philosopher1 ,lichtenberg1 of ,gottingen1 said in the year #agid3 8,people are struck and their dwellings are destroyed by lightning because they will have it so4 ,it does not matter to us whether parsimony1 carelessness1 ignorance1 or anything else is the cause of this40 ,the author asserts that this dictum may be equally applied to the present generation4 ,professor ,j4 ,h4 ,winkler1 of ,leipzig1 discovered1 in the year #agdf1 that electricity is the principal cause of thunderstorms4 ,the first lightning conductor in ,germany was erected #agfi1 at ,hamburg1 on the steeple of the ,jacobi ,church4 ,between the years #ahce and #ahfc1 a period of #ai years1 #bbch persons were killed by lightning in ,france4 ,the maximum in one year 7#ahce7 was #aaa and the minimum #dh4 ,the total number of persons struck by lightning amounted to #fgad2 of this large number #agjj persons would have escaped1 if they had been careful to avoid the neighbourhood of trees1 whilst the storms were raging4 ,the greatest number of the accidents caused by lightning occur during the months of ,july and ,august2 not a single fatal case is on record for the months of ,november1 ,december1 ,january1 and ,february4 ,the annual average number of persons killed by lightning was #c in ,belgium1 #bb in ,england1 and #aj in ,sweden4 ,in the low-lying ,departments of ,france the average is #b or #c2 the average increases rapidly for the ,mountainous ,departments to #bd1 #bh1 #ch1 #dd1 and 7in ,auvergne7 #dh4 ,the per centage of males in ,france is #fg1 females #aj1 and in the remaining cases the sex was not stated4 ,in ,prussia the proportion is #ahd males to #aje females1 in ,sweden #e males to #c females4 ,the largest number of persons killed by one discharge is #h or #i4 ,the author states that the return shock is only mechanical in its effects4 ,professor ,mller lays down the following conditions for lightning conductors3-- #a4 ,the rod must end in a very sharp point4 #b4 ,there must be no want of continuity between the extreme point and the earth contact3 and #c4 ,the different parts of the conductor must be of the requisite dimensions4 ,in practice we find that the first mentioned condition is incorrect1 as sharp points are too liable to be fused4 ,the rod must be made of a pyramidal or a conical form4 ,short rods of not above #b metres 7#f feet #g inches7 in length may be made of a cylindrical form4 ,the best form of rod is one tapering from a base of from #ej to #fj millimetres 7#b inches to #bd inches7 in diameter to a diameter of not less than #ad millimetres 7#jef inches74 ,as it is difficult to fix rods of a height of #aj metres 7#cc feet71 it is better to erect one long rod1 and several shorter ones on different parts of the roof and connect them together4 ,the principal rod should have a height of from #b to #c metres 7#h to #aj feet7 and the secondary rods 7,nebenstangen7 should be at least #a metre 7#c feet #c inches7 high4 ,the form of point universally used in ,germany is a strongly firegilded copper cone4 ,kuhn advocates the use of chemically pure silver for the points4 ,his arguments in favour of this metal are incontrovertible4 ,the conducting power of silver is #acf2 that of pure copper being #a4 ,the fusibility of silver 7#a1jjj c47 is sufficiently high for the purpose4 ,the atmosphere1 unless it contains sulphur in a gaseous or a liquid form1 has no effect on silver4 ,silver is cheaper than platinum1 and not more expensive than a gilded copper cone1 and it can be easily soldered to other metals4 ,the point should be screwed on1 as well as soldered to the rod4 ,all other but the conical form of point should be rejected4 ,the best material for the earth contact is galvanised iron4 ,as regards the protection of sea-going vessels1 ,snow ,harris's arrangement1 converting1 as it were1 the vessel into one mass of metal1 is perfect4 ,the first practicable lightning conductor for the protection of telegraph wires was constructed by ,steinheil in #ahdf4 ,his arrangement was somewhat modified by ,breguet and ,fardely4 ,meiszner introduced a real improvement4 ,on the ,prussian railway telegraphs two 8point-systems0 are in use1 one for small stations1 and the other for larger stations4 ,it is desirable that all lightning conductors be examined once a year4 ,the metallic connection throughout must be perfect1 the point must be kept free from rust1 and the earth contact must be good4 ,the whole circuit should also be tested by means of a battery and a galvanometer4 ,,earth ,,connections ,,of ,,lightning ,,conductors4 ,,by ,,lieut4-,,col4 ,,stotherd1 ,r4,e4 7,journal of the ,society of ,telegraph ,engineers1 ,may #ab1 #ahge47 7,abstracted by ,w4 ,h4 ,preece1 ,c4,e47 ,arguing from the case of a powder magazine at ,east ,london1 ,cape of ,good ,hope1 when the iron conductor was led into a cemented water-tank1 frequently dry1 and where it was destroyed1 the author raises two questions3 #a4 ,should such tanks be used for earth8 #b4 ,is iron the proper metal to use8 ,he gives a decided negative reply to the first1 and advocates the use of galvanized iron properly protected from atmospheric action4 ,he suggests rods #a inch in diameter1 or bands #b;in4 in4 thick4 ,in the discussion which followed it was mentioned that the ground about ,torquay is so insulated that plates had to be carried out to sea to secure a good earth for the telegraph there1 and that of the numerous churches which had been inspected1 there was not a single conductor that could be passed4 ,it was pointed out that when copper conductors were fixed with iron wall-eyes--a frequent thing--galvanic currents were set up1 and the conductor destroyed at the ground line4 ,it was stated that the earth connection of a supposed perfect conductor was found to be equal to a resistance of #a1jjj ,ohms4 ,mr4 ,preece1 ,major ,malcolm1 ,r4,e41 ,dr4 ,mann1 ,mr4 ,pidgeon1 ,mr4 ,kempe1 ,mr4 ,graves1 ,mr4 ,spagnoletti1 and ,mr4 ,latimer ,clark1 took part in the discussion4 ,,remarks ,,on ,,some ,,practical ,,points ,,connected ,,with ,,the ,,construction ,,of ,,lightning ,,conductors4 ,by ,r4 ,j4 ,,mann1 ,m4,d41 ,f4,r4,a4,s4 7,quarterly ,journal ,meteor4 ,soc41 ,october1 #ahge74 7,abstracted by ,g4 ,j4 ,symons1 ,f4,r4,s47 ,states that there are certain principles accepted as established facts1 e4g41 that conductors should be of metal of high conductivity1 and of adequate dimensions4 ,that in #ahed the ,french electricians held that a 8quadrangular iron bar in4 diameter1 was sufficient in conducting power for all purposes40 ,since then1 wire ropes1 owing to their pliability1 have nearly superseded solid rods1 and copper has been preferred to iron because of its higher conducting power and less liability to oxidise4 ,but provided that the iron be galvanized1 and of five times the sectional area of a copper conductor1 considers the metal immaterial4 ,author states that the resistance of a conductor increases with its length1 therefore sectional area of conductor must be increased for lofty buildings4 ,modern ,french electricians employ copper rope #jd to #jh in4 diameter4 ,m4 ,r4 ,francisque ,michel considers galvanized iron wire rope #jh in4 diameter sufficient for all ordinary cases4 ,copper wire rope #je in4 diameter 7#f oz4 per foot7 recently applied to ,st4 ,paul's ,cathedral4 ,importance of perfect earth connection strongly insisted upon1 but it is matter of some difficulty1 and the oxidation of the earth terminals1 and their inefficiency doubtless lead to most of the reported failures of lightning conductors4 ,author quotes ,pouillet and ,becquerel1 as saying1 that for the efficient discharge of the lightning1 which could be carried by a copper rod #jh in4 diameter1 contact must be obtained with #a1bjj square yards of moist earth1 but this large requirement can only easily be obtained in towns by connection with the water mains4 ,various modes of obtaining adequate earth contact by iron harrows1 ,callaud's grapnel in basket of coke1 c41 described4 ,explains the rationale of testing goodness of earth currents by the galvanometer4 ,calls attention to the destruction of upper terminals of conductors to factory chimneys by the emission of sulphurous fumes1 and suggests that they might be cased in lead4 ,calls attention to the importance of every joint being made absolutely perfect4 ,urges the superiority of points for upper terminals1 owing to their facilitating silent discharge1 and rendering lateral discharges from the conductor less probable4 ,thinks that multiple points of copper kept fairly sharp and clean are1 on the whole1 the best upper terminals4 ,considers that all large masses of metal in a building should be connected with the conductor2 but quotes ,m4 ,callaud1 who holds the opposite view4 ,dr4 ,mann1 however1 points out that if the conductor be efficient and perfect1 the accidents which ,m4 ,callaud contemplates1 and on which he bases his arguments1 could not occur4 ,calls attention to the ready path afforded by the column of heated smoke discharged by chimneys1 and hence alludes to the placing of a coronal conductor1 as well as a multiple point on important chimneys4 ,suggests the utilization of rain water pipes1 by perfecting their joints1 and securing a good earth connection at their base4 ,,on ,,the ,,protection ,,of ,,buildings ,,from ,,lightning4 ,by ,r4 ,s4 ,,brough1 #dto1 ,,mussoorie1 #ahgh4 7,abstracted by ,w4 ,h4 ,preece1 ,c4,e47 ,a carefully prepared theoretical and practical paper1 adapted for use in ,india4 ,author advocates the use of iron from its higher temperature of fusion1 and greater specific heat than copper1 its long protection from decay by galvanization and its cheapness4 ,he prefers wire cables from the absence of joints in them4 ,he gives precise instructions for the formation of a good earth1 and advocates periodic electrical tests4 ,,lightning ,,conductors4 ,by ,professors ,,ayrton and ,,perry4 7,journal ,society of ,telegraph ,engineers4 ,vol4 ,v41 #ahgf1 p4 #dab47 7,abstracted by ,w4 ,h4 ,preece1 ,c4,e47 ,the authors controvert ,clark ,maxwell's views that a building would be perfectly protected from lightning by being enclosed in a network1 or cage of wires1 without the use of the earth4 ,they object to the application of the laws of static electricity alone to such a case4 ,current induction intervenes1 and this is not subject to the screening action of a cage4 ,hence1 though a metallic cage may assist the protection of a house1 it does not do so perfectly4 ,,on ,,the ,,proper ,,form ,,of ,,lightning ,,conductors4 ,by ,w4 ,h4 ,,preece1 ,c4,e4 7,british ,association ,report1 #ahhj74 7,abstracted by ,g4 ,j4 ,symons1 ,f4,r4,s47 ,author states that ever since lightning conductors have been used1 there have been disputes as to whether the discharge passes over the surface of conductors or through their mass4 ,snow ,harris1 ,henry1 ,melsens1 and ,guillemin have held that it passed over the surface2 ,faraday held the opposite view4 ,the arguments in favour of the surface form are1 in the opinion of the author1 deductions from exploded theories1 from imperfect experiments1 or from erroneous interpretations of well ascertained facts4 ,no direct experiments have ever been made to solve the question1 as far as the author knows4 ,quantities of electricity1 that is static discharges from condensers1 are in incessant use for telegraphic purposes1 and are found to follow exactly ,ohm's laws1 even with the most delicate apparatus4 ,the knowledge of the flow of electricity through conductors1 of the retarding influence of electrostatic capacity upon this flow1 and of the distribution of charge1 has become so much greater of late years through the great extension of submarine telegraphy and the labours of ,sir ,william ,thomson1 ,clerk ,maxwell1 and others1 that the author questions if any ,english electrician would now be found to argue in favour of the surface form4 ,nevertheless1 as ribbons and tubes still continue to be used1 and it appeared very desirable to settle the question experimentally1 the author determined to try and do so4 ,first ,experiments1 ,june #bh1 #ahhj4 ,dr4 ,warren de la ,rue1 who is always ready to place his splendidly equipped laboratory at the service of science1 not only allowed the author to use his enormous battery and his various appliances1 but aided him by his advice1 and assisted him in conducting the experiments4 ,copper conductors1 #cj feet long1 of precisely the same mass1 7a7 drawn into a solid cylinder1 7b7 made into a thin tube1 and 7c7 rolled into a thin ribbon1 were first of all obtained4 ,the source of electricity was #c1bdj chloride of silver cells4 ,the charge was accumulated in a condenser of a capacity of #dbh microfarads4 ,it was discharged through platinum wire of #jabe diameter1 of different lengths4 ,the sudden discharge of such a large quantity of electricity as that contained by #dbh mf4 raised to a potential of #c1cage volts is very difficult to measure4 ,it partakes very much of the character of lightning4 ,in fact1 the difference of potential per unit length of air is probably greater than that of ordinary lightning itself4 ,it completely deflagrates #b inches of the platinum wire1 but by increasing the length of the wire it could be made to reproduce all the different phases of heat which are indicated by the various shades of red until we reach white heat1 fusion1 and deflagration4 ,hence the character of the deflagration1 which is 7by its scattered particles7 faithfully recorded on a white card to which the wire is attached1 is a fairly approximate measure of the charge that has passed1 while the length of wire1 raised to a dull red heat1 is a better one1 for any variation in the strength of the current within moderate limits is faithfully recorded by the change of colour4 ,footnote #e3 ,the electromotive force of the chloride of the silver cell is #ajc volt4 ,experiment #a4--,similar charges were passed through the ribbon1 tube1 and wire1 and in each case #b inches of wire were deflagrated4 ,no difference whatever could be detected in the character of the deflagration4 ,experiment #b4--,ten inches of wire were taken and similar charges passed through4 ,in each case the wire was raised to very bright redness1 bordering on the fusing point1 and in two cases the wire broke4 ,in each case the wire knuckled up into wrinkles1 and gave evidence of powerful mechanical disturbance4 ,the same wire was not used a second time4 ,no difference could be detected in the effect through the different conductors4 ,experiment #c4--,silver wire of the same diameter and length was used1 and similar charges transmitted through it4 ,redness was barely visible1 but the behaviour of the wire was similar in each case4 ,the conclusion arrived at unhesitatingly was1 that change of form produced no difference whatever in the character of the discharge1 and that it depended simply on mass4 ,second ,experiments1 ,july #ai1 #ahhj4 ,as it might be urged that the length of conductor tested was so short1 and its resistance so small that considerable variations might occur and yet be invisible1 similar lengths 7#cj feet7 of lead--a very bad conductor1 its resistance being twelve times that of copper--were obtained1 drawn as a wire1 made as a tube1 and rolled as a ribbon1 each being of similar weight4 ,experiment #d4--;,charges from the same condenser1 #dbh mf41 but with #c1bhj cells1 were passed through1 and the discharges observed on #f inches of platinum wire #jjabe inch diameter1 which in each case was heated to bright redness4 ,no variation whatever could be detected1 whether the wire1 the tube1 or the ribbon were used4 ,experiment #e4--;,in order to form some idea as to how closely any variation in the character of the discharge could be estimated1 a long piece of platinum wire was used1 and the length adjusted until just visible redness was obtained2 then a diminution of #aj per cent4 7#c feet7 produced a marked change to dull redness1 and further excisions raised the temperature to brighter and still brighter red4 ,the conclusion arrived at was that any change in resistance of #e per cent4 would have been clearly and easily discernible4 ,it therefore appears proved that the discharges of electricity of high potentials obey the laws of ,ohm1 and are not affected by change of form4 ,hence1 extent of surface does not favour lightning discharges4 ,no more efficient lightning conductor than a cylindrical rod or a wire rope can therefore be devised4 ,,tablissement ,,de ,,la ,,formule ,,relative ,,au ,,rayon ,d',,action ,,des ,,paratonnerres4 ,par ,,emile ,,lacoine4 7,l',electricit1 ,october1 #ahhj47 7,abstracted by ,g4 ,j4 ,symons1 ,f4,r4,s47 ,this author gives a formula for determining the area protected1 which he considers to vary with the height of the storm cloud1 and the elevation of the ground4 ,he states that the mean elevation of the storm clouds at ,constantinople is as low as about #cbe feet4 ,he says that conductors placed near the extremities of a building have their radius of protection diminished1 and therefore recommends a line conductor running round the building4 7,the circuit des faites of the ,paris ,municipal ,commission1 see ante page #fh74 ,he says that his formula leads to nearly the same results as have hitherto been adopted1 but he gives three examples1 the results of which are--length of conductor being #ajj1 radius protected is respectively #chj1 #aaj1 and #bbj4 ,,on ,,the ,,space ,,protected ,,by ,a ,,lightning ,,conductor4 ,by ,w4 ,h4 ,,preece1 ,c4,e4 7,phil4 ,mag41 ,dec41 #ahhj47 7,abstracted by ,g4 ,j4 ,symons1 ,f4,r4,s47 ,in the early part of this paper the author discusses the distribution of electricity in the space between the storm cloud and the earth's surface1 and points out that the air in an electric field is in a state of tension or strain2 and this strain increases along the lines of force with the electromotive force producing it until a limit is reached1 when a rent or split occurs in the air along the line of least resistance--which is disruptive discharge1 or lightning4 ,since the resistance which the air or any other dielectric opposes to this breaking strain is thus limited1 there must be a certain rate of fall of potential per unit length which corresponds to this resistance4 ,it follows1 therefore1 that the number of equipotential surfaces per unit length can represent this limit1 or rather the stress which leads to disruptive discharge4 ,hence we can represent this limit by a length4 ,we can produce disruptive discharge either by approaching the electrified surfaces producing the electric field near to each other1 or by increasing the quantity of electricity present upon them2 for in each case we should increase the electromotive force and close up1 as it were1 the equipotential surfaces beyond the limit of resistance4 ,of course this limit of resistance varies with every dielectric2 but we are now dealing only with air at ordinary pressures4 ,it appears from the experiments of ,drs4 ,warren de la ,rue and ,hugo ,mller that the electromotive force determining disruptive discharge in air is about #dj1jjj volts per centimetre1 except for very thin layers of air4 ,if we take into consideration a flat portion of the earth's surface1 and assume a highly charged thunder-cloud floating at some finite distance above it1 they would1 together with the air1 form an electrified system4 ,there would be an electric field2 and if we take a small portion of this system1 it would be uniform4 ,if the cloud gradually approached the earth's surface1 the field would become more intense1 the equipotential surfaces would gradually close up1 the tension of the air would increase until at last the limit of resistance of the air would be reached2 disruptive discharge would take place1 with its attendant thunder and lightning4 ,illustration3 ,fig4 #a4 ,if the earth-surface be not flat but have a hill or a building1 as ,a or ,b1 upon it1 then the lines of force and equipotential planes will be distorted1 as shown in fig4 #a4 ,if the hill or building be so high as to make the distance ,,hd equal to the limit of resistance 7fig4 #b71 then we shall again have disruptive discharge4 ,illustration3 ,fig4 #b4 ,if instead of a hill or building we erect a solid rod of metal1 ,g ,h1 then the field will be distorted as shown in fig4 #b4 ,now it is quite evident that whatever be the relative distance of the cloud and earth1 or whatever be the motion of the cloud1 there must be a space d d along which the lines of force must be longer than c c or ,h ,d2 and hence there must be a circle described around ,g as a centre which is less subject to disruptive discharge than the space outside the circle2 and hence this area may be said to be protected by the rod ,g ,h4 ,the same reasoning applies to each equipotential plane2 and as each circle diminishes in radius as we ascend1 it follows that the rod virtually protects a cone of space whose height is the rod1 and whose base is the circle described by the radius ,g c4 ,it is important to find out what this radius is4 ,illustration3 ,fig4 #c4 ,let us assume that a thunder-cloud is approaching the rod ,a ,b 7fig4 #c7 from above1 and that it has reached a point ,d where the distance ,d ,b is equal to the perpendicular height ,d ,c4 ,it is evident that if the potential at ,d be increased until the striking-distance be attained1 the line of discharge will be along ,d ,c or ,d ,b1 and that the length ,a ,c is under protection4 ,now the nearer the point ,d is to ,d the shorter will be the length ,a ,c under protection2 but the minimum length will be ,a ,c1 since the cloud would never descend lower than the perpendicular distance ,d ,c4 ,supposing1 however1 that the cloud had actually descended to ,d when the discharge took place4 ,then the latter would strike to the nearest point2 and any point within the circumference of the portion of the circle ,b ,c 7whose radius is ,d ,b7 would be at a less distance from ,d than either the point ,b or the point ,c4 8,hence a lightning-rod protects a conic space whose height is the length of the rod1 whose base is a circle having its radius equal to the height of the rod1 and whose side is the quadrant of a circle whose radius is equal to the height of the rod40 ,upon this rule the author makes the following concluding remarks3 8,i have carefully examined every record of accident that ,i could examine1 and ,i have not yet found one case where damage was inflicted inside this cone when the building was properly protected4 ,there are many cases where the pinnacles of the same turret of a church have been struck where one has had a rod attached to it2 but it is clear that the other pinnacles were outside the cone2 and therefore1 for protection1 each pinnacle should have had its own rod4 ,it is evident also that every prominent point of a building should have its rod1 and that the higher the rod the greater is the space protected40 ,,short ,,account ,,of ,,the ,,striking ,,by ,,lightning ,,of ,,the ,,railway ,,terminus ,,at ,,antwerp1 ,,on ,,the #aj,,th ,,of ,,july1 #ahfe4 ,,by ,m4 ,,melsens1 ,member of the ,royal ,academy of ,belgium4 7,abstracted by ,r4 ,van der ,broek47 ,on the date mentioned1 between three and four o'clock in the afternoon1 a violent storm burst over ,antwerp1 during which the lightning struck the ,railway ,terminus1 without1 however1 occasioning any other damage than the perforation of a single hole in one of the glass squares of the roof4 ,the author states that the effect of the discharge on this square of glass1 which was about #dmm 7#jb;in47 thick1 was remarkable2 it appeared as if it had been traversed by a projectile from below1 the perforation1 viewed from above1 being broken and chipped1 whilst viewed from below it showed a clean edge4 ,the sinuosities caused by the chipping on the upper surface had rounded edges1 and the glass appeared to have been subjected to incipient fusion4 ,not a single fragment of glass was found on the glass squares or in the gutters of the roof4 ,the author arrives at the following conclusions3 ,the square of glass was pierced in the same manner as any square of similar nature and dimensions1 placed in identical circumstances1 would be1 were it traversed by a spherical projectile fired at a low velocity from a firearm4 ,the fracture resembled one that would be produced by a missile thrown from below1 that is to say1 from the earth to the sky4 ,the form of the opening indicated that the earth was positively electrified4 ,the author notices that1 according to ,m4 ,f4 ,duprez1 negative electricity generally shows itself in abnormal conditions of the atmosphere1 during storms1 rains1 c41 and when the wind blows from the western quarters between ,n4 and ,s4 ,now1 on the day in question1 it rained and the wind blew from the west4 ,the author publicly thanks ,m4 ,ruhmkorff for his skilful and disinterested co-operation in proving the correctness of his 7the author's7 view of the distribution of the electricity at the ,antwerp discharge4 ,m4 ,ruhmkorff has1 at request1 pierced squares of ordinary glass about #amm 7#jjd;in47 thick by the discharge of his great induction apparatus charged by a powerful ,leyden battery4 ,,on ,,lightning ,,protectors ,,with ,,points1 ,,conductors1 ,,and ,,multiple ,,earth ,,connections1 ,a ,,detailed ,,description ,,of ,,the ,,lightning ,,protector ,,erected ,,on ,,the ,,town ,,hall ,,of ,,brussels ,,in #ahfe1 ,,with ,,an ,,account ,,of ,,the ,,principles ,,adopted ,,in ,,the ,,construction1 ,,by ,m4 ,,melsens1 ,,member ,,of ,,the ,,royal ,,academy ,,of ,,sciences ,,of ,,belgium4 7,abstracted by ,r4 ,van der ,broek47 ,as the author states in his preliminary observations that it is impossible to give a complete condensed description of the ,lightning ,protector1 which he erected on the ,town ,hall at ,brussels1 we will merely draw attention to a number of facts1 regarding the system followed1 some of them1 we believe1 of a novel description4 ,m4 ,daniel ,colladon1 the author states1 has observed that as a rule lightning does not strike a single part or prominent point of the objects that are struck or destroyed by it2 and that1 in the majority of cases1 it does not strike in the form of a single spark1 but in the form of a sheet with one or more principal centres of intensity4 ,the correctness of this observation1 the author considers fully borne out by the ravages which the electric discharge committed on the ,town ,hall at ,brussels1 on the #ajth ,september1 #ahfc4 ,he gives an elaborate description of the effects of the flash on the building4 ,it is interesting to note that the ravages principally took place at the side exposed to the west north-west wind1 which was blowing at the time the building was struck4 ,in the ensuing winter the ,municipal ,council of ,brussels took into consideration the necessity of protecting the ,town ,hall against a similar disaster1 and the author was requested to superintend the erection of lightning protectors on the building4 ,the characteristics of the author's system1 as exemplified by the lightning protectors erected on the ,brussels ,town ,hall1 may be briefly summarised as follows3-- #a4 ,the points are very numerous--of three kinds2 some long1 sharp1 and gilded1 others of middling length1 made of iron2 and finally some small and very sharp1 consisting of copper4 #b4 ,the points are replaced by aigrettes 7brushes of points diverging from a common base74 #c4 ,the conductor is not insulated4 #d4 ,the connections are simple and unchangeable1 the joints are each embedded in a mass of zinc4 #e4 ,the surface exposed to the air is considerable4 #f4 ,the conductor consists of thin1 and numerous wires1 which are very flexible1 so as easily to be led round all the corners of the buildings4 #g4 ,the conductor is made of galvanised iron4 #h4 ,the earth connections are multiple3 firstly1 a well within which a large surface of metal is plunged2 and1 secondly1 two enormous networks of metal pipes1 offering an immense contact surface with the earth4 ,one of these networks is in direct communication with all the reservoirs and all the water sources of the environs of ,brussels and also in indirect communication with two rivers and two canals4 ,the author has arrived at the conclusion that the height of the rod is a secondary question1 as the radius of protection has not been determined by irrefutable proofs1 and as that length is1 in comparison with the distance and the extent of the thunder-clouds1 so small a factor that it may safely be neglected4 ,the author states that he has been greatly gratified to meet with the same opinion in a paper which ,mr4 ,w4 ,h4 ,preece published in ,vol4 ,i41 ,no4 #c1 page #cff1 of the ,journal of the ,society of ,telegraph ,engineers for #ahgb3 8,when we consider the distance of the cloud and the area of its surface1 the height of a building vanishes in the general figure40 ,the author points out that ,m4 ,perrot has endeavoured to demonstrate by experiment that the neutralizing area of a lightning protector surmounted by a crown of sharp points is far more extensive than that of an ordinary protector4 ,m ,perrott further thought1 and ,,mm4 ,babinet and ,gavarret shared his opinion1 that it is sufficient to shelter the ordinary protector from discharges of lightning by arming it with numerous1 long1 sharp1 and well conducting divergent points4 ,m4 ,gavarret after having repeated ,mr4 ,perrott's experiments1 found the results so conclusive that he wrote to the author in the beginning of #ahfe3 8,it is at the present time no longer permitted to erect lightning protectors with single points40 ,the metal of which the points are made must be a very good conductor4 ,with regard to their conductivity1 the metals follow each other in the following order3 copper1 silver1 iron1 platinum4 ,no metals are used but those which resist fusion4 ,the author rejected platinum and silver3 the former because it fuses very readily by the electric discharge2 and the latter1 because it has1 in his opinion1 no advantage over copper4 ,the conductor1 although galvanized1 received several coats of paint2 but the points 7aigrettes7 of course remained metallic4 ,with regard to the general principle of connecting the protector with any masses of metal which may be about the building1 the author has ever since #ahfe endeavoured to demonstrate1 that it is not sufficient1 as might at first sight be supposed1 to form that connection at one single point2 there must be at least two points of contact1 so as always to ensure a closed metallic circuit4 ,the contact with the water presents a surface of about ten square metres 7#ab sq4 yds471 bringing both surfaces of the cylinder into account4 ,with regard to the earth connection1 the author quotes ,m4 ,perrot1 who remarks that with the ordinary protector the surface immerged offers a resistance at least #aj1jjj times greater than the conductor itself2 it is therefore necessary to increase the surface of the earth-plate as much as possible4 ,in order to retard as much as possible the oxidation of the cylinder1 the author introduced two hectolitres 7#f bushels7 of lime into the well1 thus rendering the water alkaline4 ,,de ,l',,application ,,du ,,rhe-,,lectrom,,tre ,,aux ,,paratonnerres ,,des ,t,l,,graphes4 ,,par ,m4 ,,melsens4 7,abstracted by ,r4 ,van der ,broek47 ,in this pamphlet the author describes in #a an apparatus to show the presence of atmospheric electricity in telegraph wires4 ,in #b and #d he explains how the apparatus is joined up in the ,belgian telegraph offices4 #c contains a rsum of observations made at the government telegraph offices between ,june1 #ahge1 and ,march1 #ahgf4 ,the author states in this paragraph that1 on the #aith of ,june1 #ahge1 the ,rheo-,electrometer at the office at ,louvain1 showed a deflection of #he ,east1 although there was not the slighest appearance of atmospheric electricity4 ,the fact was1 that at the time a thunder storm was raging at ,beverloo1 distant from ,louvain about #dj kilometres 7#be miles74 ,,troisi,,me ,,note ,,sur ,,les ,,paratonnerres4 ,,par ,m4 ,,melsens4 7,abstracted by ,r4 ,van der ,broek47 ,on the #crd of ,july1 #ahgd1 the church of ,ste4 ,croix1 at ,ixelles1 was struck by lightning4 ,the building was provided with a lightning protector1 which was constructed as follows3 ,the point consisted of a platinum cone of about #cj 7the form officially adopted in ,france in #ahee71 all the supports of the protector were soldered with zinc4 ,this was attached to the steeple1 and rose to #ec metres or #agd feet above the pavement4 ,it consisted of an iron rod #ah mm4 7#jga in47 in diameter 7,m4 ,e4 ,sacr's system74 ,the conductor passed from the principal roof along the roofs1 descending to a point near a pump1 behind the vestry1 where the well 7,w7 was situate4 ,there is an abundance of water in the well1 which is about #g m4 7#bc ft47 deep4 ,the conductor terminated in the well1 by a cast-iron plate #jfe m4 7#b ft4 #a in47 by #jej m4 7#a;ft4 #h in471 thus presenting a surface of #jfed m4 7#g sq4 ft474 ,a little in front of the transept there is a supplementary rod ,b #ebe m4 7#ag ft4 #c in47 high1 #aa m4 7#cf ft47 distant from the point 7c in diagram7 which was struck2 and #bb m4 7#gb ft47 distant from that point there was a second rod ,d1 whose height was #i m4 7#bi ft47 above the top of the roof4 ,the damage to the church was trifling1 but the author contends that the fact of the church having been struck at all1 proves that a building armed with a protector constructed on the usual principle is not completely protected4 ,illustration3 ,plan and ,elevation of ,church of ,ste4 ,croix1 at ,ixelles ,a4 ,principal conductor on steeple4 ,b4 ,d4 ,two supplementary receiving rods4 ,c4 ,stone cross at end of transept1 which was struck1 ,w4 ,well in which conductor made earth connection4 ,,quatri,,me ,,note ,,sur ,,les ,,paratonnerres4 ,,par ,m4 ,,melsens4 7,abstracted by ,r4 ,van der ,broek47 ,this treats #a of observations on the distribution of the spark of electric batteries and machines over numerous metallic conductors of different sections1 lengths1 and nature1 and on the passage of electricity of tension in bad conductors4 #b4 ,effects of soldered joints on the conductivity and the resistance of conductors4 ,interrupted lightning protectors4 #c4 ,the distribution of sparks from ,holtz's machine and ,ruhmkorff's coil over two conductors outwardly identical1 but one of iron and the other of copper4 ,comparative resistance to fusion and rupture for iron and copper conductors4 ,identical damage produced by discharges in several homogeneous and solid conductors4 ,,appendix ,g4 ,,catalogue ,,of ,,works ,,upon ,,lightning ,,conductors1 ,,with ,a ,,few ,,upon ,,lightning1 ,,thunder1 ,,and ,,the ,,effects ,,of ,,lightning ,,strokes1 ,chiefly extracted from the ,,ronald',s ,,catalogue1 edited by ,mr4 ,frost1 but supplemented and brought down to #ahhj by extracts from the ,catalogues of ,r4 ,,anderson1 ,f4,c4,s42 ,,latimer ,,clark1 ,c4,e42 and ,g4 ,j4 ,,symons1 ,f4,r4,s4 ,there are not many comments needed upon the following catalogue1 but a few are necessary4 ,the arrangement is1 with one exception1 strictly alphabetical under author's names2 that exception being that all the ,official ,instructions issued in ,france are placed together at the beginning of the catalogue4 ,the initials ,r1 ,c1 ,a1 ,s1 are those of the ,catalogues or ,libraries in which the works are to be found2 small type indicates that the title of the work is given in the catalogue indicated2 large type that a copy of the book is in that ,library4 ,as ,mr4 ,anderson does not state distinctly whether he possesses the books or has merely their titles1 it has been thought safer to mark those taken from his catalogue with the small ,a4 ,the existence of any specified work in a certain library is absolute proof of the existence of the book1 and hence the larger type has a certain value1 and1 besides that1 ,i purpose1 immediately after the publication of this ,report1 presenting to the ,society of ,telegraph ,engineers all the ,electrical works which are in my library but are not in the ,ronald's ,library4 ,it may therefore be assumed that most of the works to which a large type initial is prefixed are1 or soon will be1 in the splendid collections of the ,society of ,telegraph ,engineers and ,electricians4 ,the small figures in the front column show the pages of ,appendix ,f1 upon which abstracts of upwards of fifty of the following works will be found--and thus it forms an index to the works abstracted4 ,g4 ,j4 ,s4 ,,official ,,instructions1 ,,france4 7,abstracts of this series will be found on pages #ea-fi47 ,r ,s ,instruction sur les ,paratonnerres pour servir l',etablissement de ces ,appareils au-dessus des ,magasins poudre1 adopte par le ,comit des ,fortifications dans sa ,sance du #be ,aot #ahjg3 suivie des ,rapports faits 444 l',institut et l',acadmie des ,sciences1 sur cette ,instruction et sur l',etablissement des ,paratonnerres en gnral4 ,fol4 #ci pp4 #a plate4 ,paris1 #ahjh 7,this paper contains the reports by ,franklin and others1 dated #bdth ,april1 #aghd2 by ,leroy and others1 dated #bgth ,december1 #agii2 and by ,la ,place and others1 dated #bnd ,november1 #ahjg47 ,r ,instruction sur les ,paratonnerres4 ,fol4 ,paris1 #ahbc ,r ,instruction sur les ,paratonnerres adopte par l',acadmie1 #bc ,april1 #ahbc1 7,sign7 ,poisson1 ,lefevre-,gineau1 ,dulong1 ,fresnel1 et ,gay-,lussac rapporteur4 #dto4 #ea pp4 #b plates4 ,paris1 #ahbd ,s,instruction sur les ,paratonnerres adopte par l',acadmie ,royale des ,sciences le #bc ,juin1 #ahbc4 #hvo4 #ea pp4 #b plates4 ,paris1 #ahbd ,r ,s ,supplment l',instruction sur les ,paratonnerres1 prsent par la section de physique4 ,,mm4 ,becquerel1 ,babinet1 ,duhamel1 ,despretz1 ,cagniard de ,latour1 ,pouillet rapporteur4 #dto4 ,ext4 des ,comptes ,rendus1 tom4 xxxix4 #aab1 and xl41 ,sance #ah ,dc4 #ahed4 ,paris1 #ahed-e ,r ,s ,instruction sur les ,paratonnerres adopte par l',acad4 des ,sciences4 #abmo4 #acj pp4 ,cuts4 ,paris1 #ahee ,r ,s ,instruction sur les ,paratonnerres des magasins poudre4 ,rapport lu #ad ,janv41 #ahfg4 ,commissaires ,becquerel1 ,babinet1 ,duhamel1 ,vaillant1 ,pouillet1 ,fizeau1 ,regnault4 #dto4 #a plate4 #ae pp4 7,ext4 des ,comptes ,rendus1 tom4 lxiv4 ,sance #ba ,janv4 #ahfg47 ,paris1 #ahfg4 ,s,instruction sur les ,paratonnerres du ,louvre et des ,tuileries4 7,ext4 des ,comptes ,rendus1 tom4 lxvii4 ,sance #bj ,juillet1 #ahfh74 #dto4 ,paris1 #ahfh ,a ,s,instruction sur les ,paratonnerres adopte par l',acad4 des ,sciences4 ,part ,i41 #ahbc1 ,m4 ,gay ,lussac1 rapporteur2 ,part ,,ii41 #ahed1 and ,part ,,iii41 #ahfg1 ,m4 ,pouillet1 rapporteur4 #abmo4 ,paris1 #ahgd ,met4 ,soc4,analyse des ,rapports de ,m4 de ,fonvielle1 la suite de la mission qui lui avait t confie en #ahgb1 par ,m4 ,jules ,simon1 pour faire en ,angleterre une enqute sur la foudre et les ,paratonnerres4 ,fcap4 fol4 ,paris1 #ahge ,met4 ,soc4,analyse des ,rapports des ,architectes sur l',etat des ,fcap4 fol4 ,paris1 #ahge ,met4 ,soc4,instruction de la ,commission charge d'tudier l'tablissement des paratonnerres des ,edifices ,municipaux de ,paris1 adopte dans la ,sance du #bj ,mai1 #ahge4 ,fcap4 fol4 ,paris1 #ahge ,met4 ,soc4,rsum des expriences faites l',administration des ,lignes ,tlgraphiques sur les parafoudres tlgraphiques4 ,fcap4 fol4 ,paris1 #ahge ,,anonymous4 7,arranged chronologically47 ,s,petit trait du tonnerre1 esclair1 foudre1 gresle et tremblement de terre4 #abmo4 ,genve1 #aeib ,s,death of ,v4 ,tyrrell by ,lightning and ,preservation of ,sir ,j4 ,rous4 #affa ,s,dreadful ,storm of ,thunder and ,lightning1 c41 at ,bedford1 ,august #aith4 #dto4 #afgb ,s,extraordinary ,thunder and ,lightning in the ,n4 of ,ireland1 with the sad effects of the ,fall of a ,cloud4 #afhj ,r ,s----1 ,sir ,r4 ,a ,relation of the ,effect of a ,thunder-clap on the ,compass of a ,ship on the coast of ,new ,england4 #c pp4 ,also1 a ,letter concerning the former ,relation4 #b pp4 7,phil4 ,trans4 for #afhc1 xiii4 pp4 #ebj-ba47 ,london1 #afhc ,s,difesa della commune1 ed antica sentenza che i fulmini discendano dalle nuvole contro l'opinione del ,s4 ,maffei1 che si formino al basso1 ed ascendano1 etc4 #dto4 ,venezia1 #agdi ,r ,della maniera di preservare gli edificj dal ,fulmine3 ,informazione al popolo1 c4 #dto4 #ch pp4 7,vide ,toaldo47 ,at p4 #bj is inserted a translation of ,saussure's ,manifeste1 entitled ,manifesto ossia breve esposizione dell' utilit dei ,conduttori elettrici4 ,venezia1 #aggb ,r ,della maniera di preservare 444 dal ,fulmine4 #hvo4 #bb pp4 ,milano1 #aggf ,r ,neueste ,versuche zur ,bestimmung der zweckmssigsten ,form der ,gewitterstangen4 7,deutsch ,mus41 ,oct4 #aggh1 pp4 #cea-fb47 #aggh ,r ,encyclopdia ,method4 ,arts4 ,article1 ,paratonnerre4 #aghb ,s,accident by ,lightning at ,heckingham4 #dto41 plates4 #aghc ,r ,nuovo metodo di costruire i ,parafulmini praticato in ,padova4 #dto4 #b pp4 7,opuscoli ,scelti1 vi4 #chj47 ,milano1 #aghc ,r ,dell' efficacit dei conduttori elettrici1 ,dubbj proposti ai ,fisici moderni4 #hvo4 #aghd ,r ,maniera pratica di fare li ,conduttori #dto4 7,printed by order of the ,magistrato della ,sanit di ,venezia47 7,vide ,marzari47 ,venezia1 #aghg ,r ,einige gegen die ,gewitterableiter gemachte ,frankfort1 ,einwrfe beantwrtet4 #hvo4 #agij ,r ,dubbii sull' ,efficacia dei ,conduttori4 #hvo4 #abb pp4 #a plate 7,vide ,bragadin47 ,venezia1 #agie ,r ,nachricht und ,zeichnung von einer im ,jahre #aggh1 am ,schlossthurme1 zu ,dresden1 angebrachten ,ableitung4 7,schrift1 d4 ,leipz4 konomische ,societt1 th4 v4 pp4 #bbb-cb47 ,r ,risposta dell' autore dei ,dubbii sull' efficacia dei ,conduttori1 alla giunta al ,giornale ,astrometeorologico del ,gr4 ,toaldo4 7,vide ,bragadin47 ,r ,plain ,directions for safe ,lightning ,conductors for ,lightning4 #hvo4 #di pp4 ,note4--,part of a work4 ,begins at p4 #cc ,r ,account of a mass of #gjjj ,bricks of a ,wall displaced several feet by ,lightning4 #hvo4 ,manchester1 7,manchester ,memoirs1 ii4 #b47 n4d4 ,r ,relazione del ,turbine scoppiato in ,venezia nel ,giorno #af ,giugno1 #ahje4 ,data ,venezia1 #ai ,giugno4 #hvo4 7,da ,rio ,giornale1 ix4 #bff47 ,padova1 #ahje ,r 7,r4 ,r47 ,death by ,lightning4 ,man killed at ,colwall1 near ,ledbury1 #ahag4 #hvo4 7,phil4 ,mag4 #a4 #cae47 ,london1 #ahag ,r ,on ,lightning ,conductors of ,straw4 7,see ,lapostolle47 #ahbj ,r ,on the ,cure of a case of ,paralysis by ,lightning4 #hvo4 #b pp4 7,phil4 ,mag4 lix4 #bhg47 ,london1 #ahbb ,r ,remarks upon ,mosely's article on ,solar ,spots of #ahaf in ,phil4 ,mag4 xlix4 #ahb4 #hvo4 #c pp4 7,from ,new ,monthly ,mag4 for ,january1 #ahba4 ,at p4 #gb1 ,chain ,cables as ,conductors47 ,london1 #ahba ,r ,anleitung zur ,verfertigung und ,bentzung der ,blizableiter4 #hvo4 #dc pp4 #b plates4 7,translation of ,french ,official ,report ,strasbourg1 of #ahbd1 without name of ,translator47 #ahbd ,r ,tubes formed by ,lightning4 #hvo4 #a p4 7,phil4 ,mag4 or ,annals1 iv4 #bbh47 ,london1 #ahbh ,r ,memoir on ,lightning ,conductors--,reply to a ,prize ,question4 ,bordeaux1 #ahcg4 7,vide ,bourges1 ,secretary of the ,bordeaux ,bordeaux1 ,academy1 ,sance #ahcg1 p4 #hc47 #ahcg ,r ,on the knowledge of the ,ancients concerning ,lightning ,conductors4 #hvo4 7,fraser's ,magazine1 #ahci87 ,london1 #ahci8 ,r ,sur l',histoire du ,paratonnerre1 #ahdc4 7,le ,portique1 #are livraison1 ,jan4 #ahdc1 p4 #ea47 #ahdc ,r ,part of ,bulletin des ,mois de ,mars1 ,avril41 ,mai1 ,juin1 ,juillet1 ,aot1 #ahed4 #hvo4 7,toulouse ,acad4 series #d1 vol4 iv4 ,at p4 #dhc1 ,de ,clos1 ,effets de la ,foudre sur ,toulouse1 un ,paratonnerre47 #ahed ,r ,de la ,construction des ,paratonnerres4 ,quelques ,rflexions sur le ,rapport de la ,commission de l',acadmie des ,sciences du #ad ,janvier1 #ahfg4 #hvo4 #bi pp4 ,paris1 #ahfh ,r ,s ,abbadie1 ,a4 ,d'4 ,sur le tonnerre en ,ethiopie4 #dto4 ,paris1 #aheh ,r ,a ,achard1 ,f4 ,k4 ,kurze ,anleitung lndliche ,gebude vor ,gewitterschde sicher zu stellen4 #hvo4 ,berlin1 #agih ,r ,alden1 ,t41 ,jun4 ,effects of ,lightning on the ,house of ,captain ,manning in ,portsmouth1 ,new ,hampshire2 in a letter to ,dr4 ,eliot4 #dto4 #b pp4 7,mem4 ,amer4 ,cambridge1 ,acad41 iii4 p4 #ic47 ,u4,s41 #ahji ,c ,a ,anderson1 ,r4 ,lightning ,conductors3 their ,s history1 nature1 and mode of application4 7#abj7 ,large #hvo4 ,london1 #ahgi ,s ,on the necessity for a regular ,inspection of ,lightning ,conductors 7,brit4 ,ass4 ,rep4 #ahhj47 #hvo4 ,london1 #ahhj ,r ,arago1 ,f4 ,notices scientifiques4 ,sur la ,grle et des ,paragrles1 c4 #abmo4 ,paris1 #ahbg ,r ,c ,sur le ,tonnerre4 #abmo4 ,a ,s ,paris1 #ahcg ,s ,ueber ,gewitter4 #abmo4 ,weimar1 #ahci ,r ,a ,meteorological ,essays4 ,translated by ,s ,sabine4 #hvo4 ,london1 #ahee ,a ,arnold4 ,blitzableiter zum ,schutz der ,wrterbuden4 ,polyt4 ,centralblatt4 #fej4 #ahea ,a ,arrowsmith1 ,j4 ,on the ,use of ,black ,paint in averting the effects of ,lightning on ,ships4 #ahda ,r ,astier1 ,c4 ,b4 ,notice sur les ,paragrles pointes2 projet de paragrles flammes et expriences comparatives du pouvoir lectrique des flammes et des pointes4 ,toulouse1 #hvo4 #ahbi ,r ,s ,ayrton1 ,w1 ,e41 and ,perry1 ,j4 ,lightning 7#acb7 ,conductors2 an ,answer to ,prof4 ,j4 ,c4 ,maxwell's suggestion to surround buildings with a conducting cage4 7,jour4 ,soc4 ,tel4 ,eng41 vol4 v4 p4 #dab47 ,london1 #ahgf ,babinet4 7,see ,official ,instructions1 ,france47 ,r ,baier1 ,j4 ,w4 ,de ,fulmine1 fulgure1 et tonitru hiemale4 #agjf ,r ,baldwin1 ,l4 ,an ,account of a very curious appearance of the ,electric ,fluid produced by raising a ,kite in the time of a thundershower2 in a ,letter to ,j4 ,willard4 #dto4 7,mem4 ,amer4 ,acad4 i4 part ii4 #beg1 old series47 ,boston1 #aghe ,r ,observations on ,electricity1 and an improved mode of constructing ,lightning-rods2 in a letter to ,j4 ,willard4 #dto4 7,letter dated ,january #be1 #agig47 7,mem4 ,amer4 ,acad4 ii4 part ii4 ,charlestown1 #if1 old series47 ,u4,s41 #ahjd ,r ,a ,barberet1 ,d4 ,dissertation sur le ,rapport qui existe entre les ,phnomnes du ,tonnerre et ceux de l',electricit4 #b ,bordeaux1 vols4 #dto4 #agej ,r ,a ,barbier de ,tinan4 ,mmoires sur les ,s ,conducteurs pour prserver les difices de la foudre2 par l',abb ,jh4 ,toaldo2 traduits de l',italien avec des ,notes et des ,additions1 par ,m4 ,barbier de ,tinan4 ,strasbourg1 #hvo4 #bda pp4 #c plates4 #aggi ,r 7,nuove7 ,considerazioni sopra i conduttori del ,sig4 ,barbier di ,tinan4 ,traduz4 dal ,francese4 #dto4 #dc pp4 ,venezia1 #aggi ,note--,this is a printer's translation of ,barbier's ,considerations sur les ,conducteurs en gnral1 appended to his translation of ,toaldo's ,dei ,conduttori per preservare gli edifizj da ,fulmini4 #dto4 #aggh1 nuova edizione4 ,r ,barletti1 ,c4 ,nuove ,sperienze ,elettriche1 secondo la ,teoria del ,sig4 ,franklin e le produzioni del ,p4 ,beccaria4 #hvo4 #acd pp4 ,milano1 #agga ,r ,bartletti1 ,c4 ,descrizione de' fulmini di ,porta ,comasina1 e del ,duomo di ,milano1 e de' confronti loro coi principali effetti dei fulmini4 #aghe ,r ,dei ,conduttori del fulmine4 ,r ,bartaloni1 ,d4 ,lettera sopra il fulmine caduto nel d #ah ,ap4 #aggg1 sulla spranga posta nella torre del palazzo pubblico della citt di ,siena4 #hvo4 7,there is also an ,english translation of the above74 ,siena1 #aggg ,r ,mem4 sul conduttore ,elettrico collocato nella torre della ,piazza di ,siena4 #dto4 #cf pp4 #a plate4 7,atti dell' ,accad4 di ,siena1 vi4 #bec47 ,siena1 #agha ,r ,relazione sopra un supposto ,fulmine caduto nella ,cappella della ,piazza di ,siena il d #g ,giugno dell' ,anno #aghd4 #dto4 #h pp4 7,atti dell' ,accad4 di ,siena1 vii4 #fa47 ,siena1 #agid ,c ,bartholomei 7,glanvilla74 ,opus de rerum proprietatibus inscriptum3 ad comunem studioso utilitatem1 fol4 7,liber xix47 #aeai ,s,baudisius1 ,a4 ,de lapide ,fulminari4 #dto4 ,witteberg1 #affh ,a ,beaufort1 ,dr4 ,a4 de4 ,notice sur les ,chateauroux1 ,paratonneres4 #hvo4 #ahge ,r ,a ,beccaria1 ,g4 ,b4 ,lettere dell' ,elettricismo4 ,fol4 ,bologna1 #ageh ,s ,della elettricita terrestra atmosferica4 #dto4 ,turin1 #agge ,r ,a ,a ,treatise upon artificial electricity4 #hvo4 ,london1 #aggf ,r ,beck1 ,d4 ,fassliche ,unterredung1 ,gebude vor dem ,einschlagen des ,blitzes zu ,salzburg1 bewahren4 #hvo4 7,heinsius1 i4 #baj47 #aghf ,r ,s ,becquerel1 ,a4 ,c4 ,e4 ,trait de ,paris1 l'lectricit4 #c vols4 #hvo4 #ahee-ef 7,see ,official ,instructions1 ,france47 ,r ,s ,bennet1 ,a4 ,new experiments on ,electricity1 ,thunder1 and ,lightning4 #hvo4 ,derby1 #aghi ,a ,bergman1 ,t4 ,tal on mjeligheten at frexomma askans skadeliga werkningar4 ,stockholm1 #dto4 #agfd ,r ,rede von der ,mglichkeit des ,donners ,stockholm1 schdlichen ,wirkungen vorzukommen4 #dto4 #agfd ,r ,zusatz zu ,vorhergehenden1 i4e4 ,wilcke1 ,bemerkungen bei einem den #cj ,may1 #agfi4444 ,donnerschlage4 #hvo4 #e pp4 7,k4 ,akad4 ,schwed4 ,abh4 xxxii4 #abh47 ,leipzig1 #aggj ,r ,bertholon1 de ,st4 ,lazare4 ,mmoire sur un nouveau moyen de se prserver contre la ,montpellier1 ,foudre4 #dto4 #aggg ,r ,lettre ,m4 de la ,tourette1 sur les ,paratonnerres ascendants et descendants de la ,ville de ,lyon4 7,samml4 zu ,phys4 xix4 ,mai #aghb1 p4 #chb47 #aghb ,r ,nouvelles ,preuves de l'efficacit des ,montpellier1 ,paratonnerres4 #dto4 #bh pp4 #c plates4 #aghc ,r ,a ,de l'lectricit des ,mtores4 #b vols4 ,s #hvo4 ,paris1 #aghg ,r ,s ,die ,electricitt d4 ,lufterscheinungen4 ,leignitz1 #b vols4 #hvo4 #agib ,r ,beyer4 ,on ,lightning-conductors1 c4 #hvo4 #b editions4 ,paris1 #ahjf-i ,r ,bianchini1 ,g4 ,an ,extract by ,rolli1 ,p41 of an ,italian ,treatise1 written by ,bianchini1 ,j41 upon the ,death of the ,countess ,cornelia ,zangari ne' ,bandi1 of ,cesena4 ,to which are subjoined ,accounts of the ,death of ,hitchell1 ,j4 7see ,hilliard1 ,j471 who was burned to death by ,lightning1 and ,grace ,pitt at ,ipswich1 whose body was consumed to a coal4 #dto4 ,london1 #ai pp4 7,phil4 ,trans4 xliii4 #ddg47 #agdd-de ,r ,bianchini1 ,g4 ,f4 ,on the ,vertical ,rod on the ,chteau di ,duino in the ,friuli4 #dto4 7,mmoires de l' ,acad4 pour #agfd1 edit4 orig4 p4 #dd47 ,paris1 #agfd ,r ,a ,bigot1 ,p4 ,anweisung zur ,anlegung1 ,s ,construction und ,veranschlagung der ,blitzableiter4 #hvo4 ,glogau1 #ahcd ,c ,biot4 7,see ,official ,instructions1 ,france47 ,r ,bladth1 ,p4 ,j4 ,bericht von zwei ,blitz-,schlgen1 welche das ,schwedische ,schiff ,stockholms-,schloss in ,ost-,indien1 #aggg1 getroffen haben4 #hvo4 #ad p4p4 7,neue ,schwedische ,akademie ,abhandlung1 i4 #aghj1 p4 #ig7 ,translation4 ,leipzig1 #aghj ,c ,blagden ,nairne4 ,proceedings relative to the ,accident by ,lightning at ,heckingham4 ,report to ,royal ,society4 7,phil4 ,trans47 ,london1 #aghb ,a ,blesson4 ,verbesserung an ,blitzableitern4 ,verhandl4 des ,vereins zur ,beforderung des ,gewerbefleisses in ,preussen4 ,jahrg4 #ahca1 #bej4 #ahca ,r ,a ,bckmann1 ,j4 ,l4 ,ueber ,blitzableiter4 ,eine ,s ,abhandlung auf hchsten ,befehl ,carlsruhe1 bearbeitet4 ,neue ,auflage von ,wucherer4 #ahcj ,r ,ueber ,blitzableiter4 #c ,auflage von ,g4 ,carlsruhe1 ,f4 ,wucherer4 #hvo4 #ahci ,r ,a ,bodde1 ,j4 ,b4 ,grundzge zur ,theorie der ,blitzableiter4 #hvo4 #hd p4p4 ,mnster1 #ahji 7,anderson says also 8,munster1 #ahjd407 ,r ,boddington4 ,an accurate ,statement of ,facts relative to a ,stroke of ,lightning which happened on the #acth ,april1 #ahcb4 #hvo4 ,london1 #ahcb ,bodino1 ,j4 ,univers natur theatrum in quo rerum omnium ,effectrices cause et fines quinques libris discutiuntur4 #hvo4 #fcc pp4 ,lugduni1 #aeif ,r ,a ,boeckmann1 ,j4 ,l4 ,ueber die ,blitzableiter4 ,s ,eine ,abhand4 auf hchsten ,befehl des ,carlsruhe1 ,frsten4 #hvo4 #hj pp4 #agia ,r ,bona e ,corner4 ,relazione dell' andamento ed effetti del ,fulmine che colp il ,campanile 444 di ,s4 ,francesco della ,vigna 7in ,venezia71 l'anno1 #aghj1 #bd ,maggio4 #dto4 #h pp4 ,venezia1 #aghj 7,this title is abridged from that of an official report made by ,bona and ,corner1 officers of ,artillery47 ,s,bonjean1 ,j4 ,mtorologie2 effets produits ,chambry1 par un coup de foudre4 #hvo4 #ahdh ,r ,bottis1 ,g4 ,breve relazione degli effetti di un ,fulmine che cadde in ,napoli il mese di ,giugno del presente anno #aggd2 e alcune considerazioni sopra i medesimi4 #dto4 #bg pp4 ,napoli1 #aggd ,r ,s ,boudin1 ,m4 ,histoire physique et ,mdicale de la ,foudre1 et de ses effets sur l'homme1 les animaux1 les plantes1 les difices1 les navires4 #hvo4 #ca pp4 7,ext4 ,annales d',hygine1 c47 ,paris1 #ahed ,r ,de la ,foudre considre au point de vue de l',histoire1 de la ,mdecine lgale1 et de l',hygine publique4 #hvo4 #ej pp4 ,paris1 #ahee ,r ,histoire de la ,foudre et des ,paratonnerres4 #hvo4 #eg pp4 cuts4 7,ext4 ,annales d',hygine47 ,paris1 #ahee ,r ,bourges4 ,rapport sur les travaux de l',acadmie1 ,sance #ahcg1 #bb ,sept4 #hvo4 7,sances de l',acadmie de ,bordeaux pour ,bordeaux1 #ahcg1 p4 #hc47 #ahcg ,note4--,contains notices of two memoirs1 as replies to a prize question on ,lightning-conductors4 ,the first is an anonymous one1 which speaks of the forms of roofs and of metallic masses spread over the edifice1 c4 ,the second is by ,mermet1 of ,pau1 who received a gold medal1 but not the prize4 ,r ,bragadin 7or ,anonymous74 ,dubbii sull' efficacia de' ,conduttori elett4 #hvo4 #abb pp4 #a plate4 ,venezia1 #agie ,r ,risposta dell' autore dei ,dubbii sull' efficacia dei ,conduttori1 alla giunta al ,giornale ,astrometeorologico del 444 ,toaldo4 #hvo4 #ca pp4 ,s,braun1 ,a4 ,a4 ,ueber zwei am #bf ,juli bei ,berlin v4 ,blitz getroff4 ,eichen4 ,berlin1 #ahfi ,r ,breitinger1 ,d4 ,reflexionen ob es wohl gerathen wre1 ,strahlenableiter in unserer ,stadt ,zrich einzufhren4 ,zurich1 #aggf ,r ,nachricht ber das ,einschlagen des ,blitzes in einen ,wetterableiter1 nebst ,berichtigung einiger ,begriffe ber die ,wirkung der ,ableiter4 ,zurich1 #aghf ,r ,breitinger1 ,d4 ,ragguaglio d'un ,fulmine caduto in un ,conduttore4 #dto4 #c pp4 7,opuscoli ,scelti1 ix4 #baj47 ,milano1 #aghf ,r ,instruction fr diejenigen1 welche sich mit der ,verfertigung und ,visitation der ,blitzableiter beschftigen4 ,zrich1 #ahbe ,r ,a ,instruction ber ,blitzableiter im ,canton ,zrich4 #dto4 ,zurich1 #ahcj ,r ,brewster1 ,sir ,d4 ,on the ,life ,boat1 the ,lightning-conductor1 and the ,light-house4 #hvo4 7,north ,british ,review1 xxxii4 #dib1 ,november1 #ahei47 #ahei ,a ,bright1 ,e4 ,b4 ,lightning ,conductors4 7,mech4 ,mag41 lix4 #bdf47 #ahec ,r ,s ,brook1 ,a4 ,miscellaneous experiments and remarks on ,electricity #dto4 ,norwich1 #aghi ,c ,brooks1 ,d4 ,facts and inferences relating to ,lightning and ,lightning ,rods4 #hvo4 #af ,philadelphia1 pp4 #ahgb ,a ,lightning and ,lightning ,rods4 7,journal of the ,franklin ,institute47 lxvi4 #d4 #ahgc 7#aag7 ,s ,atmospheric electricity4 #hvo4 ,philadelphia1 #ahgh 7#acb7 ,s,brough1 ,r4 ,s4 ,protection of ,buildings ,mussoorie1 from lightning4 #dto4 7,lithographed47 #ahgh ,c ,brown1 ,r4 ,disputatio ,philosophica ,de ,trajecti ad ,fulmine4 #dto4 #af pp4 ,rhenum1 #afib 7#hi7 ,s,buchanan1 ,g4 ,an account of the chimney of the ,edinburgh ,gas ,works4 #hvo4 7,proc4 ,edinburgh1 ,roy4 ,scot4 ,soc4 ,arts47 #ahea ,r ,s ,buchenau1 ,f4 ,mittheilungen ber einen interressanten ,blitzschlag in mehreren ,stieleichen4 #dto4 #ae pp4 ,dresden1 #ahfg ,r ,bucher4 ,einige gegen die ,gewitterableiter ,frankfort1 gemachte ,einwrfe beantwortet4 #hvo4 #agij ,r ,a ,buchner1 ,o4 ,die ,construction und ,anlegung ,s der ,blitzableiter4 zum ,schutze aller 7#abh7 ,arten von ,gebuden1 ,seeschiffen1 and ,telegrafenstationen2 nebst ,kostenvoranschlgen4 #hvo4 #aeb pp4 mit einem ,atlas von #f ,foliotafeln4 ,weimar1 #ahfg ,s ,de bliksemafleiders1 door ,c4 ,j4 v4 ,doorn4 #hvo4 ,haarlem1 #ahfg ,a ,die ,construction4 #hvo4 #bnd ,ed4 #hvo4 ,weimar1 #ahgf ,r ,buissart4 ,mmoire sur les divers ,avantages qu'on pourroit retirer de la ,multiplicit des ,conducteurs ,electriques1 ou ,paratonnerres4 ,lu l',acad4 d',arras4 #bd ,avril1 #agha4 7,saumlez1 ,phys4 ,supplem4 #aghb4 xxi4 pp4 #adj-dh7 #aghb ,r ,mmoire juridique sur les ,conducteurs ,electriques4 7,from ,van ,swinden1 p4 #acg2 ,van ,troostwyk and ,krayenhoff1 p4 #bda47 ,a ,bunsen1 ,j4 ,versuch1 wie die ,meteora des ,donners und ,blitzes des ,aufsteigens der ,dnste1 incl4 des ,nordscheins1 aus elektr4 ,versuchen1 herzuleiten und zu erklren4 #hvo4 ,lemgo1 #agec ,r ,burnaby1 ,a4 ,voyages dans l',amrique ,septentrionale1 ,traduit de l',anglais4 ,lausanne1 7,conductors melted by ,lightning47 #aggh ,s,burt4 ,miscellaneous ,scientific papers4 #ahfa-fe ,r ,busse1 ,f4 ,g4 von4 ,beruhigung ber die neuen ,wetterableiter4 #hvo4 #fb pp4 ,leipzig1 #agia ,r ,beschreibung einer wohlfeilen und sichern ,blitzableitung1 mit neuen ,grnden und ,erfahrungen4 #hvo4 #a plate4 ,leipzig1 #ahaa ,r ,a ,butschany1 ,m4 ,dissertatio de ,fulgure et ,tonitru ex ,phnomenis ,electricis4 #dto4 ,gttingen1 pp4 #a et #b4 7,poggendorf1 i4 #cec47 #ageg ,r ,a ,der ,blitz entsteht nicht durch ,entzndung einiger brennbaren ,theilchen die in der ,luft schweben1 und ist auch kein ,feuer4 7,beitrage zu ,hannov4 ,magazin1 #agfa47 ,hanover1 #agfa ,r ,eine ,unvollkommenheit der ,blitzableiter1 nebst ihrer ,verbesserung4 #hvo4 7,from ,poggendorff1 i4 #cec47 ,hamburg1 #aghg ,cagniard de ,latour4 7,see ,official ,instructions1 ,france47 ,c ,a ,callaud1 ,a4 ,trait des ,paratonnerres4 ,s ,large #hvo4 7#ajc7 ,paris1 #ahgd ,r ,camerer1 ,j4 ,w4 ber das ,einschlagen des ,gewitters auf zwei mit ,blitzableitern versehenen ,husern4 7,tubing4-,bltter1 #ahae1 ,bd4 ii47 ,tubing1 #ahae ,r ,a ,cardanus1 ,g4 ,de fulgure4 ,liber unus4 ,fol4 7,cardani ,geronimo ,opera omnia4 #aj vols1 folio1 vol4 ii47 ,lugd4 #affc ,r ,castelli1 ,c4 ,dissertazione sull' origine delle straordinarie meteore dell' anno #aghc1 e sulla maniera d' impedire i fulmini e le grandini4 #hvo4 7,from ,,ms4 ,catalogue1 ,padua ,academy47 ,milano ,r ,a ,s ,cavallo1 ,t4 ,a complete ,treatise on ,london1 #aggg1 ,electricity4 #hvo4 7,many editions47 c4 ,r ,cerini1 ,g4 ,impossibilit fisico-chimica del paragrandine4 ,milano1 #ahba ,r ,chamberlayne1 ,j4 ,on the effect of ,thunder and ,lightning at ,stampford ,courtney1 in ,devonshire4 #dto4 7,phil4 ,trans4 #agab47 ,london1 #agab ,a ,chantrel4 ,ueber ,blitzableiter4 7,polyt4 ,journ41 lxxxvi4 #agi47 #ahdb 7#gj7 ,s,chapman1 ,sir ,f4 ,e4 ,instructions as to the application of ,lightning ,conductors4 #hvo4 7,army ,circulars47 #ahge ,r ,chappe1 ,d',auteroche4 ,observations sur l'orage du #f ,aot1 #agfg1 et d'un coup de foudre qui s'est lev de la terrasse de l',observatoire4 #dto4 7,mm4 de ,paris1 #agfg1 ,mm4 p4 #cdd47 ,paris1 #agfg ,r ,voyage en ,californie pour l',observation de ,vnus sur le disque du ,soleil le #c ,juin1 #agfg4444 ,redig et publi par ,m4 ,cassini fils4 #dto4 #agj pp4 #d plates4 ,s 7,on ,lightning 7as ascending71 p4 #ca1 and reference to the same subject in his ,voyage en ,sibrie74 ,paris1 #aggb ,r ,voyage en ,sibrie4 7,pogg4 i4 #dbj1 says #c vols4 #dto47 ,paris1 #agfc ,r ,chevallier1 ,j4 ,g4 ,instruction sur les paratonnerres4 ,paris1 #ahbc ,r ,chigi1 ,a4 ,lettera ad un amico sopra il ,fulmine caduta1 #ah ,aprile1 #aggg1 nella spranga4444 torre del ,palazzo4444 di ,siena4 ,siena1 #ahdd ,r ,chiminello1 ,v4 ,risposta 444 al commento 444 nel ,giornale ,astrometeorologico1 #ahjf1 del ,sig4 ,g4 ,scaguller1 #abmo4 #bd pp4 7,on ,lightning ,conductors47 ,venezia1 #ahjf ,r ,precauzione d'applicare il secondo conduttore ovvero l',emissario per preservare gli edifizii dai ,fulmini4 7,giornale ,astrometeorologico1 #ahjf47 ,padova1 #ahjf ,r ,chinale e ,compa4 ,paragrandine4 ,istruzione4 #hvo4 #be pp4 #a plate4 7,estratti del ,propagatore47 ,torino1 #ahbh ,r,c,s,clark1 ,latimer4 ,on the ,storms experienced by the ,submarine ,cable ,expedition in the ,persian ,gulf1 #ahfi4 7,jour4 ,met4 ,soc47 #hvo4 ,london1 #ahgc ,r ,clerc4 ,compte-rendu4 #a;er ,smestre de #ahai4 #hvo4 7,lyon's ,acad4 ,comptes-rendus47 ,lyon1 #ahai ,note4--,mention of a work received from le ,comte de ,lezai-,marnesia 444 sur les ,paratonnerres et les ,paragrles--,n4 ,d4 ,r ,close1 ,d4 ,passage d'une letter 444 sur les effets de la ,foudre sur la chane du paratonnerre d'un vaisseau4 #hvo4 #b pp4 7,toulouse ,acad4 #d;e srie1 tome iv4 p4 ,toulouse1 #dhc47 #ahed ,r ,cohn1 ,f4 ,ein interessanter ,blitzschlag beschrieben4 #dto4 #b plates4 7,acad4 ,leop4 #ahef1 vol4 xxvi4 part i4 p4 #agg47 #ahef ,die ,einwirkung des ,blitzes auf ,bume4 #dto4 7,acad4 ,leop487 ,s,colladon1 ,d4 ,mmoire sur les effets de la ,foudre sur les arbres et les plantes ligneuses1 et l'emploi des arbres comme parratonnerres4 to4 ,genve1 #ahgb 7#aag7 ,s,collin et ,fils4 ,paratonnerres4 7,extract from ,catalogue47 #dto4 ,r ,collinder4 ,de fulguribus4 #dto4 7,from ,watts47 ,upsal1 #afhf ,r ,contessi1 ,m4 ,disquisizione sui paragrandini4 #dto4 #bf pp4 ,treviso1 #ahbf ,r ,costantini1 ,g4 ,a4 787 ,difesa della 444 ,sentenza che i ,fulmini discendono dalle nuvole 444 ,riflessioni4 #dto4 #ahd and #ab ,venezia1 pp4 #agdi4 ,r ,cowper4 7,poet47 ,letter to ,tilloch1 from ,j4 ,s4 ,s41 containing an ,extract from the #crd vol4 p4 #agh1 in a letter to the ,rev4 ,john ,newton1 of ,cowper's ,correspondence as published by ,hayley4 ,this extract contains an account of two ,fireballs which burst 8on the steeple1 or close to it10 at ,olney4 #hvo4 7,phil4 ,mag4 xix4 #bif47 ,london1 #ahjd ,r ,crause 7,krause71 ,r4 ,w4 ,de fulmine tactis4 ,jen1 #afid ,r ,crse1 ,g4 ,de ,fulmine4 #dto4 7,from ,amsterdam1 ,watts47 #afei ,r ,s ,crosse1 ,a4 ,memorials of the late4 #hvo4 ,london1 #aheg ,d',abbadie4 7,see ,abbadie1 ,d'47 ,a ,dalibard1 ,m4 ,histoire abrge de l',electricit4 #b vols4 #hvo4 ,paris1 #agff ,d',auteroche4 7,see ,chappe ,d',auteroche47 ,r ,davies1 ,e4 ,an account of what happened from ,thunder in ,carmarthenshire2 partly from the woman's mouth that suffered by it1 partly from what was observed by others2 communicated to the ,royal ,society by ,eames ,j41 as he received it in a letter from ,davies ,e41 dated ,pencarreg1 ,saturday1 ,dec4 #f1 #agbi-cj4 #dto4 #e pp4 ,london1 7,phil4 ,trans4 xxxvi4 #ddd47 #agbi-cj ,r ,daviet de ,foncenex1 ,f4 ,rcit d'une foudre ascendante clate sur la tour du fanal de ,villefranche4 7,biblioteca oltramontana1 #aghi47 #aghi ,r ,davy1 ,sir ,h4 ,preservation from ,lightning4 7,portable conductor47 #hvo4 #a p4 7,phil4 ,mag4 lix4 #dfh47 ,london1 #ahbb ,de ,fonvielle4 7,see ,fonvielle1 ,de47 ,de ,fremery4 7,see ,fremery1 ,de47 ,de ,la ,pylaie4 7,see ,la ,pylaie1 ,de47 ,de ,la ,rive4 7,see ,la ,rive1 ,de47 ,r ,a ,delaval1 ,e4 ,h4 ,an account of the effects of ,lightning1 c4 #dto4 7,phil4 ,trans4 #agfd47 ,london1 #agfd ,r ,della ,bella1 ,g4 ,trattato sopra l'utilit dei conduttori elettrici4 7,pogg4 i4 #aci47 ,r ,noticias historicas1 e praticas circa do modo de defender os edificios dos ontrages dos raios4 #hvo4 ,lisboa1 #aggc ,r ,dell',acqua1 ,c4 ,norme pratiche per ben costruire ed applicare i ,parafulmini4 #dto4 #cg pp4 #a plate 7lith47 ,milano1 #ahei ,r ,a ,dempp1 ,k4 ,w4 ,vollstndiger ,unterricht in ,s der ,technik der ,blitzableitersetzung4 #hvo4 ,mnchen1 #ahdb ,de ,romas4 7,see ,romas1 ,de47 ,des ,cartes ,renati4 ,principia philosophi4 ,amstelodami1 #dto4 #caf pp4 #afej ,despretz4 7,see ,official ,instructions1 ,france47 ,de ,st4 ,lazare4 7,see ,bertholon de ,st4 ,lazare47 ,r ,d',hombre ,firmas1 ,l4 ,a4 ,effets de la ,foudre4 7,rsum des travaux de l',acadmie de ,toulouse pendant ,toulouse1 #ahci-dj-da47 #ahdc ,r ,dietrich1 ,p4 ,f4 von4 ,sur les conducteurs des difices anciens4 #dto4 7,schrift4 ,gesellsch4 naturf4 ,fr4 in ,berlin1 xxv4 #aghd47 ,berlin1 #aghd ,r ,s ,dingley4 ,r4 ,vox ,cli1 or ,observations of ,thunder4 ,sm4 #hvo4 ,london1 #afeh ,r ,divisch1 ,p4 8,erfand einen ,wetterableiter4 ,beschrieben in ,pelzel's ,abbild1 bhm u4 mhr4 ,gelehrt4 ,bd4 iii40 7,from ,poggendorff1 i4 #ehj47 ,r ,s ,dove1 ,h4 ,w4 ,ueber ,electricitt4 #hvo4 ,berlin1 #ahdh ,r ,dralet4 ,on a ,trombe1 with thunder1 c4 ,toulouse1 #ahcj ,drebble1 ,c4 ,einkurtzer ,tractat von der ,natur4 ,der ,elementen und wie sie den ,wind ,regen ,blitz und ,donner verorfachen4 #abmo4 ,franckfurt1 #be pp4 #afbh ,duhamel4 7,see ,official ,instructions1 ,france47 ,r ,dujardin1 ,c4 ,trait lmentaire de l',electricit extrait en partie du grand ouvrage de ,m4 ,becquerel1 et renfermant un ,article pratique sur les ,paratonnerres par ,m4 ,gay-,lussac4 ,s4,a4 #abmo4 ,paris4 ,dulong4 7,see ,official ,instructions1 ,france47 ,r ,du ,moncel1 ,t4 ,thorie des clairs4 #hvo4 ,cherbourg1 #df pp4 #ahed ,r ,notice historique et thorique sur le tonnerre et les clairs4 #hvo4 #ed pp4 ,paris1 #aheg ,s ,expos des applications de l',electricit4 #e vols4 #ahgb-gh ,a ,dupin1 ,c4 ,observations au sujet du ,rapport sur l',etablissement de ,paratonnerres bords des ,vaisseaux4 7,compt4 ,rend41 xxxix4 #aaei47 #ahed ,r ,du ,prez1 ,f4 ,mmoire en rponse 444 sur ,bruxelles1 l'lectricit de l'air4 #dto4 #ahdc ,r ,s ,statistique des coups de foudre qui ,bruxelles1 7#ia7 ont frapp des paratonnerres4 #dto4 #ahei ,r ,du ,tour1 ,e4 ,f4 ,mmoires sur les effets lectriques du tonnerre tomb prs de ,riom en ,auvergne4 #dto4 7,mm4 de ,paris1 an4 #agff1 ,hist4 p4 #cg47 ,paris1 #agff ,r ,a ,eberhard1 ,j4 ,p4 ,vorschlge zur bequemern und sicheren ,anlegung der ,pulvermagazin4 #hvo4 ,halle1 #agga ,s,edmonds1 ,r4 ,on the two great thunderstorms1 with extraordinary agitations of the sea in #ahdf4 #hvo4 ,r ,a ,eeles1 ,h4 ,letter concerning the cause of ,thunder4 #dto4 7,phil4 ,trans4 #ageb1 p4 #ebd47 ,london1 #ageb ,r ,a ,eisenlohr1 ,w4 ,anleitung z4 ,ausfhrung u4 ,carlsruhe1 ,s ,visitation d4 ,blitzableiter4 #h vo4 #ahdh ,s ,second edition1 with #c plates4 ,carlsruhe1 #ahfg ,a ,eitelwein1 ,j4 ,a4 ,kurze ,anleitung auf welche ,art ,blitzableiter an den ,gebuden anzulegen sind4 #hvo4 ,berlin1 #ahjb ,r ,elice1 ,f4 ,lettera sulla niuna influenza del suono delle campane per attrarre il fulmine4 ,genova1 #ahag ,r ,influenza delle campane sul fulmine4 #hvo4 #c pp4 7,bibl4 ,ital4 xxxii4 #dbc47 ,milano1 #ahbc ,r ,osservazioni sull' ,istruzione dei ,parafulmini approvata dalla ,r4 ,acad4 delle ,scienze di ,parigi il d #bc ,aprile #ahbc e pubblicata nel #ahbd4 #hvo4 #h pp4 ,genova1 #ahbf ,r ,lettera del 444 ,f4 ,elice 444 al sig4 ,c4,f4 #hvo4 #c pp4 7,bibl4 ,ital4 xlv4 #acf47 ,milano1 #ahbg ,note4--,on the effects of lightning on the tower of the lighthouse at ,genoa1 ,jan4 #dth1 #ahbg4 ,r ,istruzione sui ,parafulmini4 ,lettera 444 al ,p4 ,c4 ,dentone4 #hvo4 #bd pp4 ,genova1 #ahci ,r ,istruzione sui ,parafulmini2 lettera 444 indirizzata al ,pittore ,c4 ,dentone4 ,seconda ,edizione con aggiunte dell' autore4 #hvo4 #cb pp4 ,genova1 #ahda ,r ,osservazioni sui ,parafulmini4 ,luglio #ahdc e ,nota sulla conducibilit di parecchi metalli per l'elettrico1 e proposta di fare le punte dei parafulmini di palladio4 #a ,agosto #ahdc4 #hvo4 #aa pp4 ,genova1 #ahdc ,r ,ellinger1 ,a4 ,beitrge zur ,erluterung d4 ,vorstellung von ,wetterwolken und ,blitzen4 ,munchen1 7,munchen ,denkschr4 #ahjc-f47 #ahjc-f ,r ,englefield1 ,sir ,h4 ,c4 ,some particulars respecting the ,thunderstorm at ,london and in its vicinity on the #cast of ,august1 #ahaj4 #hvo4 #d pp4 7,phil4 ,mag4 xxxvi4 #cdi47 ,london1 #ahaj ,s,esebecius1 ,j4 ,s4 ,de fulmine et tonitru4 #dto4 #afei ,r ,esser1 ,ferd4 ,abhandl4 b4 ,blitzableiter4 #hvo4 ,munster1 #aghe ,fait1 ,e4 ,mac4 7,see ,macfait47 ,c ,falconer1 ,w4 ,observations on the knowledge of the ancients respecting ,electricity 7,memoirs of the ,literary and ,phil4 ,soc4 ,manchester1 vol4 iii4 p4 ,warrington1 #bgh47 #hvo4 #agij ,r ,felbiger1 ,j4 ,i4 von4 ,die ,kunst ,thuerme1 oder andere ,gebude1 vor den schdlichen ,wirkungen des ,blitzes1 durch ,ableitung zu bewahren 7angebracht an einem ,thurm74 #hvo4 #aaj pp4 #a plate4 ,breslau1 #agga ,r ,wie weit gewhren wohl ,gewitterableiter1 ,sicherheit fr ,pressburg1 umstehende ,gebude8 #aghg ,r ,felkel1 ,a4 ,wahre ,beschaffenheit des ,donners4 ,wien1 #aghj ,r ,a ,ferguson1 ,j4 ,an introduction to electricity4 7#crd ed47 #hvo4 ,london1 #aggh ,s,ferguson1 ,r4 ,m4 ,electricity4 #abmo4 #ahga ,r ,ferri1 ,p4 ,riflessioni sopra gli ,argomenti addotti dal 444 ,maffei 444 intorno la ,formazione del ,fulmine4 #dto4 #eb pp4 ,vicenza1 #agdh ,r ,fiedler1 ,k4 ,g4 ,merkwrdige ,blitzschlaege4 #hvo4 7,gilb4 ,ann4 lxviii47 #ahdf ,r ,fiedler1 ,k4 ,w4 ,ueber ,blitzrohren in ,deutschland und ,ungarn4 ,r ,fischer1 ,d4 ,relatio de fulgure tonitru et fulmine4 ,de insolito quodam phnomeno ,kesmarkini die #aj ,aug4 #agag4 ,breslau ,r ,fischer1 ,j4 ,b4 ,de fno sub combustione per fulminis ignem in massam seu scoriam calcariam redacto4 #dto4 7,nov4 ,act4 ,acad4 ,nat4 ,cur4 iii4 #agcc47 ,breslau1 #agcc ,r ,follini1 ,g4 ,sul passaggio del fulmine 444 delli #f ,agosto1 #agie1 nel ,tempio di ,s4 ,vercelli1 ,andrea in ,vercelli4 #hvo4 #di pp4 #a plate4 #agie ,r ,fonda4 ,sopra la maniera di preservare gli edifizii dal ,fulmine4 ,roma1 #aggj ,r ,c ,fonveille1 ,w4 de4 ,eclairs et ,tonnere4 ,s #abmo4 ,paris1 #ahfg ,s ,thunder and ,lightning 7translated by ,phipson74 #hvo4 ,london1 #ahfh ,a ,s ,eclairs et ,tonnerres4 #hvo4 ,paris1 #ahfi ,a ,de l',utilit1 des ,paratonnerres4 #hvo4 ,paris1 #ahgd 7,see ,official ,instructions1 ,france47 ,r ,forbes1 ,eli4 ,an account of the effects of ,lightning on a large rock in ,gloucester1 in a letter 444 to 444 ,m4 ,cutler1 7dated ,july #c1 #aghc74 #dto4 #d pp4 7,mems4 of the ,american ,acad41 ,old ,series1 i4 #bec1 part ii47 ,boston1 #aghe ,r ,forster1 ,b4 ,description of an electrical instrument called 8,the ,thunderstorm ,alarum40 #hvo4 #b pp4 #a plate4 7,phil4 ,mag4 xlvii4 #cdd47 ,london1 #ahaf ,r ,forster1 ,t4 ,on simultaneous ,thunderstorms4 #hvo4 #b pp4 7,phil4 ,mag4 lx4 #aie47 ,london1 #ahbb ,s,fournet1 ,j4 ,sur la distribution des coups de foudre ,lyon4 #hvo4 ,lyon1 #aheb ,r ,fowler1 ,t4 ,a remarkable case of the morbid effects of ,lightning successfully treated4 7,medical and ,philosophical ,commentary by a ,society of ,physicians in ,edinburgh1 vol4 vi47 ,edinburgh4 ,a ,franklin1 ,b4 ,experiments and ,observations in ,electricity made at ,philadelphia1 in ,america4 #hvo4 ,london1 #agea ,s ,expriences et ,observations4 #abmo4 #ageb ,r ,letter from ,dr4 ,b4 ,franklin to ,d4 ,hume1 ,esq41 on the method of securing houses from the effects of ,lightning4 ,edinburgh1 #hvo4 #ae pp4 #agga ,r ,c ,experiments and ,observations4 7#eth ,s edition47 #dto4 7#gi7 ,london1 #aggd ,a ,franklin1 ,b4 ,experiments on the ,utility of long-pointed ,rods for securing ,buildings from damage by ,strokes of ,lightning4 ,london1 #aggi ,r ,s ,mmoire sur la manire d'armer d'un conducteur la cathdrale de ,strasbourg et sa tour4 #hvo4 #aghj ,entered in the ,ronald's ,catalogue1 under ,barbiere de ,tinan1 but issigned by ,franklin4 7,see ,official ,instructions1 ,france47 ,r ,frecksel4 ,bemerkungen ber ,blitzschlge4 #ahai ,r ,frost1 ,a4 ,j4 ,catalogue of books and ,c,s papers relating to ,electricity1 c41 compiled by ,sir ,francis ,ronalds1 ,f4,r4,s4 #hvo4 xxvii4 #efd pp4 ,london1 #ahhj ,r ,s ,fremery1 ,n4 ,c4 ,de4 ,dissertatio philos1 ,lugd4 ,batav41 inauguralis de ,fulmine4 #dto4 #agij ,fresnel4 7,see ,official ,instructions1 ,france47 ,r ,fuchs1 ,j4 ,c4 ,von einem merkwrdigen ,wetterschlage in ,potsdam4 7,allerneueste ,mannigfaltigkeiten1 #aghb47 #aghb ,r ,zustze und ,ergnzungen der ,nachricht von einem merkwrdigen ,wetterschlage in ,potsdam4444 7,allerneueste ,mannigfaltigkeiten1 ,j4 ii4 ,th4 iii47 ,r ,gallitzin1 ,d4 ,a4 ,f4 ,observations sur les conducteurs4 ,addresse l',acad4 de ,bruxelles2 ,july #f1 #aggh4 #dto4 #aj pp4 #a plate4 ,la ,haye1 #aggh ,r ,garipuy4 ,mmoire sur un coup de ,tonnerre arriv prs la ville de ,castres 444 ,rflexions sur les conducteurs lectriques4 7,lu #aa ,avril1 #aghb47 #dto4 7,toulouse ,acad4 #are srie1 tom4 ii4 p4 ,toulouse1 #ahh47 #aghd ,r ,gattoni1 ,g4 ,c4 ,lettera all editore sui ,fulmini di ,ritorno4 7,data ,como1 #ae ,luglio1 #ahjh47 #dto4 #ad pp4 #a plate 7lith474 7,nuova ,scelt4 d',opusc4 ii4 #bhi #caj47 ,milano1 #ahjg ,r ,s ,gavarret1 ,j4 ,trait d',electricit4 #b ,paris1 vols4 #hvo4 #aheg-eh ,r ,s ,lehrbuch d4 ,electricitt4 7,translated ,leipzig1 by ,arendt47 #b bde4 #ahei-fj ,r ,gay-,lussac4 7,see ,official ,instructions1 ,france47 ,s,gersdorf1 ---- v4 ,ueber die atmosphrische ,electricitt4 ,grlitz1 #ahjb ,r ,gilbert1 ,i4 ,a method of affording relief to persons injured by ,lightning4 ,in a letter from ,mr4 ,isaiah ,gilbert to the ,rev4 ,mr4 ,steele4 #hvo4 #b pp4 7,phil4 ,mag4 xvii4 #cjf47 ,london1 #ahjc ,r ,gilii1 ,f4 ,l4 ,memoria fisica sopra il ,fulmine ,caduto in ,roma sulla casa dei ,p4 ,p4 ,filippini di ,s4 ,maria in ,vallicella1 detta comunemente la chiesa nuova nel d #bf ,novembre1 #agha4 #abmo4 #bh pp4 ,roma1 #aghb ,r ,breve ragionamento sopra il conduttore 444 innalzato sulla ,basilica di ,sta4 ,maria degli ,angioli4 #hvo4 #bb pp4 ,roma1 #agic ,r ,gilly und ,eytelwein4 ,kurze ,anleitung1 auf welche ,art ,blitzableiter an d4 ,gebuden anzubringen sind4 #hvo4 #c plates4 ,berlin1 #agih ,r ,kurze ,anleit4 c4 7,blitzableiter74 #hvo4 #c plates4 ,berlin1 #ahjb ,r ,kurze ,anleit1 c4 #c;e ,aufl4 #hvo4 ,berlin1 #ahai ,gineau4 7,see ,official ,instructions1 ,france4 7 ,r ,giorgi1 ,e4 ,ueber ,blitzableiter4 7,vide ,majocchi ,annali1 viii4 #agh47 ,s,gray1 ,j4 ,w4 ,son4 ,lightning1 its destructive action on buildings4 #hvo4 ,london1 #ahge8 ,r ,green1 ,w4 ,p4 ,selection of papers on the subject of fixed ,lightning ,conductors to the masts of ,h4,m4's ,navy1 constructed so as to pass from the truck to the keelson 444 illustrated by engravings1 c4 #hvo4 ,london1 #ahbd ,r ,on ,lightning ,conductors for ,ships4 #ahbh ,s ,precautions to avoid accidents by ,lightning4 #hvo4 #ahcg ,r ,greimble4 ,dissertatio physica de genu ,agust4 ,vind4 progressu et effectibus fulminis4 #abmo4 #agei ,a ,grenet1 ,e4 ,construction des ,paratonnerres4 #hvo4 ,paris1 #ahgc ,r ,grimm1 ,j4 ber die ,namen des ,donners4 ,eine academische ,abhandlung vorgelesen am #ab ,mai1 #ahec4 #dto4 #bh pp4 ,berlin1 #ahee ,r ,a ,gross1 ,j4 ,f4 ,grundstze der ,blitzableitungskunst geprft1 und durch einen merkerwrdigen ,fall erlutert4 ,nach dem ,tode des ,verfassers herausgegeben von ,j4 ,f4 ,w4 ,widenmann4 #hvo4 #bbh pp4 #a plate4 ,leipzig1 #agif ,r ,guazzi1 ,a4 ,transunto del ,ragguaglio d'un ,fulmine caduto presso ,casalmaggiore con danno di tre persone4 #dto4 #c pp4 7,opusc4 ,scelt4 xiv4 #cja47 ,milano1 #agia ,r ,guden1 ,p4 ,p4 ,von der ,sicherheit wider die ,gttingen1 ,donnerstrahlen4 #hvo4 #bjj pp4 #aggd ,r ,gutle und ,luz4 ,unterricht vom ,blitz und den ,blitz-und-,wetter ,ableitern1 zur ,errinerung und ,beruhigung sonderlich der ungelehrten1 und des gemeinen ,mannes von ,f4 ,luz neu bearbeitet von ,j4 ,k4 ,gutle4 ,nrnberg1 ,erster ,theil4 #hvo4 #bbb pp4 #a plate4 #ahjd ,r ,gutle1 ,j4 ,c4 ,lehrbuch der praktischen ,blitzableitungskunst 444 als ,fortsetzung der 8,theoretischen ,blitzableitungslehre40 ,nrnberg1 #hvo4 #ddf pp4 #af plates4 #ahjd ,r ,a ,algemeine ,sicherheitsregeln fr ,nrnberg1 ,jederman bey ,gewitter4 #hvo4 #ahje ,r ,fasslicher ,unterricht wie man sich bei ,gewittern vor den 444 ,wirkungen des ,blitzes ohne ,blitzableiter sicher 444 ,nrnberg1 verwahren kann4 #hvo4 #adj pp4 #ahje ,r ,a ,neue ,erfahrungen ber die beste ,art ,nrnberg1 ,blitzableiter anzulegen4 #hvo4 #ahab ,r ,neue wissenschaftliche ,erfahrungen1 ,entdeckungen und ,verbesserungen1 c4 #hvo4 #bgb pp4 #d plates4 ,mnchen1 #ahbf ,r ,hachette1 ,j4 ,n4 ,p4 ,sur la formation des tubes fulminaires4 #hvo4 7,ann4 de ,chim4 xxxvii4 #ahbh47 ,paris1 #ahbh ,r ,haidinger1 ,w4 ,ritter ,von4 ,niedrigste ,hhen von ,gewitterwolken 7,zwei ,flle in ,erinnerung gebracht47 #hvo4 #aj pp4 7,aus den ,sitzungsberichten #aheb1 der k4 ,akad4 der ,wissenschaften abgedruckt4 ,vol4 ix4 ii4 ,heft47 ,wien1 #ahec ,r ,s ,die sdwestlichen ,blitzkugeln am #bj ,octbr4 #ahfh4 ,nachtrag zu der ,mittheilg4 am #e ,novbr4 #hvo4 #b pp4 7,sitzb4 d4 k4 ,akad4 d4 ,wiss4 ,dec4 ,heft4 #ahfh lviii4 ,bde47 ,wien1 #ahfh ,r ,s ,ein kugelfrmiger ,blitz am #cj ,aug4 #ahfe1 gesehen zu ,feistritz bei ,peggau in ,stiermark4 #hvo4 #d pp4 7,sitzb4 d4 k4 ,akad4 d4 ,wiss4 ,dec4 ,heft4 #ahfh1 lviii4 ,bde47 ,wien1 #ahfh ,s,hajingi1 ,b4 1 ,seu ,giess ,disquisitio de ,fulmine ,naturalis4 #dto4 ,hassorum1 #affj ,r ,hallencreutz1 ,d4 ,beobachtung an ,gewitterwolken welche ,blitze gegen einander geben zu ,pello innerhalb des ,polarkreises4 #hvo4 #c pp4 #a plate4 7,k4 ,schwed4 ,akad4 ,abh4 xxxv4 #he47 ,leipzig1 #aggc ,r ,halley1 ,e4 ,observation sur les coups de ,tonnerre multiplis et extraordinaires4 #dto4 7,mm4 de ,paris1 #agca4 ,hist4 p4 #ai47 ,paris1 #agca ,s,hamberg1 ,h4 ,e4 ,om den s4 k4 luftelektriciteten4 #hvo4 ,upsala1 #ahgb ,r ,hannemann1 ,j4 ,l4 ,de fulminis effectu miro4 7,miscell4 ,acad4 ,nat4 ,cur47 #afhe ,a ,hare1 ,r4 ,ueber die ,ursachen1 warum ,wetterableiter in einigen ,fllen nicht schtzen1 und die ,mittel dieselben vollkommen schtzend zu machen nebst einer ,widerlegung der herrschenden ,idee dass ,metalle die ,elektricitt vorzglich anziehen4 ,aus4 ,gill's ,technological ,repository1 ,nov41 #ahbg1 im ,polyt4 ,journ41 xxvii4 #bfh4 #ahbh ,r ,harris 7afterwards ,sir71 ,william ,snow4 ,electrical ,conductors for ,ships4 ,experiment in ,plymouth ,harbour4 #hvo4 #g pp4 7,phil4 ,mag4 lx4 #bca47 ,london1 #ahbb ,r ,c ,observations on the effects of ,a ,s ,lightning on floating bodies1 c41 with an account of a new method of applying fixed and continuous ,conductors of ,electricity to the ,masts of ,ships4 ,letter to ,sir ,t4 ,b4 ,martin4 #dto4 #hi pp4 #e plates4 ,london1 #ahbc ,note4--,the illustration accompanies plate i4 ,the lines on the paper originally consisted of gold leaf4444 ,a discharge has been passed over the gold leaf to show by its deflagration the course of the electric matter4 ,r ,on the relative powers of various metallic substances as ,conductors of ,electricity4 ,read ,dec4 #ad1 #ahbf4 #dto4 #g pp4 #a plate4 7,phil4 ,trans47 ,london1 #ahbg ,r ,a ,on the utility of fixing ,lightning ,plymouth1 ,conductors on ,ships4 #hvo4 #bc pp4 #ahcj ,r ,a series of papers on the defence of ,ships and ,buildings from ,lightning4 #hvo4 #df pp4 7,nautical ,magazine1 xxv47 ,london1 #ahce ,r ,s ,inquiries concerning the elementary laws of electricity4 #dto4 ,london1 #ahcf ,r ,a series of three ,papers1 termed ,illustrations of cases of damage by ,lightning in the ,british ,navy4 7,nautical ,magazine for #ahch47 ,london1 #ahch ,a ,on the ,protection of ,ships from ,lightning4 7,annals of ,electricity1 ii4 #ha47 #ahch ,r ,s ,state of the question relating to the protection of the ,british ,navy from ,lightning1 by the method of fixed ,conductors of ,electricity1 as proposed by ,plymouth1 ,mr4 ,snow ,harris4 ,with appendix4 #hvo4 #ahch ,c ,s ,history of #bbj ships struck by ,lightning4 #ahci ,r ,a ,on ,lightning ,conductors1 and on certain principles in ,electrical science2 being an investigation of ,mr4 ,sturgeon's experimental and theoretical researches in ,electricity1 published by him in the ,annals of ,electricity1 c4 #hvo4 #ab pp4 #a plate4 7,phil4 ,mag4 for ,dec41 #ahci1 p4 #dfc47 ,london1 #ahci ,r ,s ,copy of the report and evidence from 7#hc7 the ,commission appointed to inquire into the plan of ,w4 ,s4 ,harris1 relating to the protection of ,ships from the effects of ,lightning4 ,ordered by the ,house of ,commons to be printed1 #aath ,feb41 #ahdj4 ,folio4 #if pp4 #ab plates4 ,london1 #ahdj ,s ,state of the question relating to the protection of the ,british ,navy4 #hvo4 #ahdj ,r ,on the course of the ,electrical discharge1 and on the effects of ,lightning on certain ships of the ,british ,navy4 #hvo4 7,edinb4 and ,lond4 ,phil4 ,mag41 ,feb4 and ,march1 #ahdj47 ,london1 #ahdj ,r ,on ,lightning ,conductors1 and the effects of ,lightning on ,h4,m4's ship 8,rodney0 and certain other ships of the ,british ,navy2 being a further examination of ,mr4 ,sturgeon's ,memoir on ,marine ,lightning ,conductors4 #hvo4 #ab pp4 #a plate4 7,annals of ,electricity1 iv4 #dhd47 ,london1 #ahdj ,r ,on the supposed ,electro-magnetical effects of ,marine ,lightning ,conductors4 7,nautical ,magazine1 ,enlarged ,series1 ,no4 #b1 vol4 for #ahda7 #ahda ,r ,observations on the action of ,lightning ,conductors4 7,proc4 ,london ,elec4 ,soc4 for #ahdb47 ,london1 #ahdb ,r ,on the effects of ,lightning on the ,british ship 8,underwood10 #hvo4 #h pp4 7,nautical ,mag4 for ,june1 #ahdb47 ,london1 #ahdb ,r ,c ,on the nature of ,thunderstorms1 and ,a ,s the means of protecting ,buildings and 7#he7 ,shipping against 444 ,lightning4 #hvo4 ,london1 #ahdc ,r ,harris1 ,w4 ,s4 ,a theoretical and practical view of ,thunderstorms1 and the protection of ,buildings and ,ships from ,lightning4 ,london1 #ahdc ,r ,on ,damage by ,lightning in the ,british ,navy4 #hvo4 #ff 7pp4 ,extract from the ,nautical ,magazine1 #ahdc47 ,london1 #ahdc ,s ,brief history of #bbj ,ships4 #hvo4 #ahdd ,r ,s ,meteorology of ,thunderstorms at ,sea1 with analytical deductions2 and a history of the effects of ,lightning on #baj ships of the ,royal ,navy4 #hvo4 ,london1 #ahdd ,note4--,the first part was printed in the 8,nautical ,magazine0 after the second part1 containing the history of cases1 had been completed4 ,the first part has #ah pp42 the second part is entitled1 8,damage by ,lightning in the ,british ,navy10 and has #ff pp4 ,r ,remarkable instances of the protection of certain ,ships of ,h4,m4's ,navy from the destructive effects of ,lightning2 collected from various authorities4 #hvo4 ,plymouth1 #ah pp4 #ahdd ,r ,remarkable instances of defence of certain ,ships of the ,royal ,navy from the destructive agency of ,lightning1 with practical and theoretical deductions4 ,london1 #ahdf ,r ,letter to the ,secretary of the ,incorporated ,society for ,building ,churches1 c41 on the ,preservation of ,plymouth1 ,public ,buildings from ,lightning4 #hvo4 #ahdg ,r ,a ,public ,official ,letter to the ,india ,board1 dated ,june #ba1 #ahdg1 relative to a ,board ,order requiring all ,transports to be fitted with his ,conductors4 #ahdg ,s ,history of #bbj ships of the ,royal ,navy4 #hvo4 #ahdg ,r ,remarkable instances of the protection of certain ,ships 444 from the destructive effects of ,lightning4 #hvo4 #fa pp4 #b plates4 ,london1 #ahdg ,r ,s ,instructions for the application of permanently fixed ,conductors in ,h4,m4's ships1 drawn up for the use of ,h4,m4's dockyards4 ,printed by order of the ,lords ,commissioners of the ,admiralty4 ,london1 #ahdh ,r ,letter to the ,earl of ,wilton on returns 444 relative to 444 fixed ,metallic ,conductors employed in ,h4,m4's ,plymouth1 ,navy4 #hvo4 #ce pp4 #ahdi ,r ,letter on the ,preservation of ,public ,buildings from 444 ,lightning 7revised7 addressed to the 444 ,society for building ,churches1 c41 dated ,december1 #ahdg4 #hvo4 #ab pp4 ,london1 #ahej ,r ,s ,on the relative ,cost and ,efficiency of permanent and temporary forms of ,lightning ,conductors as applicable to the ,plymouth1 defence of the ,royal ,navy4 #hvo4 #bg pp4 #ahej ,r ,remarkable instances of the ,preservation of certain ,ships of the ,royal ,navy from ,lightning4 ,abridged from ,official and other authenticated ,reports4 ,plymouth1 #hvo4 #ai pp4 #ahej ,r ,destruction of ,merchant ,ships4 ,shipwreck by ,lightning4 #hvo4 #f pp4 7,nautical ,magazine for ,november1 #aheb47 ,london1 #aheb ,r ,papers relating to ,harris's ,lightning ,conductors and the destructive effects of ,lightning on ,ships4 ,fol4 #aa pp4 #b plates4 ,london1 #aheb ,r ,papers relative to ,harris's ,lightning ,conductors1 ,appendix1 with ,addendum of #a sheet4 ,fol4 #cg pp4 ,london1 #aheb ,r ,review of the ,history and ,progress of the general system of ,lightning ,conductors 444 in the ,royal ,navy4 #hvo4 #aj pp4 7,reprinted from the ,nautical ,magazine for ,march1 #ahec47 #ahec ,r ,s ,shipwrecks by ,lightning4 ,copies of 7#ij7 papers relative to ,shipwrecks by ,lightning as prepared by ,sir ,snow ,harris1 and presented by him to the ,admiralty4 ,fol4 #hb pp4 #e plates4 ,london1 #ahed ,s,harris1 ,w4 ,s4 ,on the relative cost and efficiency of ,lightning ,conductors4 #hvo4 #ahei ,r ,a ,a treatise on ,frictional ,electricity4 7,edited by ,c4 ,tomlinson47 #hvo4 ,london1 #ahfg ,s,harting1 ,p4 ,notice sur un cas de formation de fulgurites et sur la prsence d'autres fulgurites dans le sol ,amsterdam1 de la ,nerlande #dto4 #ahgd ,r ,hartmann1 ,j4 ,f4 ,verbesserter ,versuch seines knstl4 elektr4 ,blitzes4 #hvo4 7,hamb4 ,mag4 xxiv4 #agei47 ,hamburg1 #agei ,a ,gedanken ber den ,ursprunz der ,luftelektricitt bei ,gewittern4 #agfc ,r ,newen ,erklarung der ,entstehungsart der ,donnerwetter4 7,gttingischen gemein1 ,gttingen1 ,abhandl4 von ,j4 #agge47 #agge ,r ,s ,harward1 ,s4 ,a ,discourse of the several ,kinds and ,causes of ,lightnings1 written by occasion of a fearefull ,lightning which1 on the #agth day of ,nouember1 ,anno ,dom4 #afjf1 did in a very short time1 burne vp the spire steeple of ,bletchingley1 in ,surrey1 and in the same melt into fragments a ,goodly ,ring of ,bells4 #dto4 ,london1 #afjg ,r ,hassencamp1 ,j4 ,m4 ,wie ein ,ort durch ,wetterableiter su sichern4 ,rinteln1 #aghb ,r ,von den grossen ,pltzen d4 ,strahlableiter1 u4 ihrer vortheilhaftesten ,einrichtung zur ,beschtzung ganzer ,stdte4 ,rinteln1 #aghd ,r ,a ,hauch1 ,a4 ,w4 von4 ,von der ,luftelekt4 besonders mit ,anwendung auf ,kopenhagen1 ,gewitterableiter4 #hvo4 #ahjj ,r ,a ,hehl4 ,anleitung zur ,errichtung und ,untersuchung der ,blitzableiter fur ,bauverstndige1 ,bau- und ,feuerbeschauer ,stuttgart1 und ,gebude-,inhaber4 #hvo4 #ed pp4 #ahbg ,r ,heinrich1 ,p4 ,ueber die ,wirkung des ,geschtzes auf ,gewitterwolken4 #dto4 7,neue ,abhandl4 der ,baierischen ,akad4 ,philos4 v4 p4 i47 ,mnchen1 #aghi ,a ,helfenzreider1 ,j4 ,e4 ,verbesserung der ,eichstadt1 ,blitzableiter4 #hvo4 #aghc ,r ,vorschlag 444 die ,blitzableiter zu ,salzburg1 verbessern4 #hvo4 #ae pp4 #aghe ,r ,a new invention in ,lightning ,conductors4 #hvo4 7,abhand4 eine ,privat-,gesellschaft1 vol4 i4 ,no4 #ab47 ,mnchen1 #agib ,r ,handgriffe bey ,errichtung eines ,blitzableiters von verbesserter ,art4 #hvo4 7,abhand4 einer ,privat-,ges4 in ,ober-,deutschland1 ,th4 i4 p4 #aic47 ,mnchen1 #agib ,r ,helmuth1 ,j4 ,h4 ,von d4 wohlthtig4 ,erfindung d4 ,blitzableiters4 7,braunschw4 ,anzeig1 #ag #g1 ,s4 #ee47 #aggg ,r ,helvig1 ,c4 ,g4 ,bemerkungen ber ,blitz und ,donner1 nebst ,vermuthungen ber das ,entstehen der ,luft-,erscheinungen4 #hvo4 #cb pp4 #a plate4 7,gilbert's ,ann4 d4 ,physik1 li4 ,s4 #b1 ,s4 #aj47 ,leipsig1 #ahae ,r ,hemmer1 ,j4 ,j4 ,beschreibung einiger merkwrdiger ,wetterschlge4 #dto4 7,commentat4 ,acad4 ,theodoro-,palatin iv4 ,mannheim1 ,phys4 p4 #hg47 #aghj ,r ,zergliederung des bestndigen ,elektrizitts-,trgers4 #dto4 7,commentat4 ,acad4 ,theodoro-,palatin iv4 ,phys4 p4 ,mannheim1 #id47 #aghj ,r ,kurzer ,begriff u4 ,nutzen d4 ,dsseldorf1 ,wetterableiter1 u4 s4 w4 #hvo4 #aghb ,a ,kurzer ,begriff und ,nutzen der ,mannheim1 ,blitzableiter4 #hvo4 #aghc ,r ,a ,kurze und deutliche ,anweisung wie man1 durch einen in jedem ,orte wohnenden ,schmied1 oder andere in ,metall arbeitende ,handwerker1 eine sichere ,wetterableitung mit sehr geringen ,kosten in allerhand ,friedrichstadt1 ,gebuden anlegen lassen kann4 #hvo4 #aghc ,hemmer1 ,j4 ,j4 ,de fulminis ictibus in campanas1 qu pulsantur1 ubi electricitas nubium ac fulminis theoria1 nova et uberiore luce perfunduntur4 #dto4 7,commentat4 ,acad4 ,theodoro-,palatin v4 ,mannheim1 ,phys4 p4 #bcg47 #aghd ber d4 ,glockenluten bey ,gewittern4 #dto4 7,commentat4 ,acad4 ,mannheim1 ,theodoro-,palatin v4 #aghd47 #aghd ,a ,s ,anleitung ,wasserableiter an allen ,gattungen von ,gebuden auf die sicherste ,frankfurt1 ,art anzulegen4 #hvo4 #aghf ,r ,anleitung ,wetterableiter 444 ,offenbach1 anzulegen4 #hvo4 #aghf ,r ,anleitung ,wetterleiter 444 anzulegen4 ,mannheim1 #bnd edition4 #hvo4 #bcb pp4 #aghh ,r ,s ,verhaltungsregeln wenn man sich zur gewitterzeit in keinem bewaffneten ,mannheim1 gebude befindet4 #aghi ,r ,unterr4 z4 sicherst ,anleg4 d4 ,mannheim1 ,wetterableiter4 #hvo4 #ahjh ,r ,a ,rathgeber wie man sich vor ,gewittern in unbewaffneten ,gebuden verwahren soll4 ,mannheim1 #hvo4 #a plate4 #ahji ,r ,conductorum fulmineorum vim egregiam tribus recentioribus exemplis docet4 #dto4 7,commentat4 ,acad4 ,theodoro-,palatin vi4 ,mannheim1 ,phys4 #eaf47 #agij ,r ,s ,nachricht von den in ,kurpfalz angelegtern ,wetterleiten4 #dto4 7,commentat4 ,acad4 ,theodoro-,palatin iv4 ,phys4 p4 #ba47 ,mannheim ,r ,enarrationes conductorum fulminis superiore quinquennio variis in locis a se positorum4 #dto4 7,commentat4 ,acad4 ,mannheim1 ,theodoro-,palatin v4 ,phys4 p4 #bie47 #aghd ,r ,s ,henley1 ,w4 ,an account of the death of a person destroyed by ,lightning in the ,chapel in ,tottenham ,court ,road1 and its effects on the building2 as observed by ,mr4 ,wm4 ,henley1 ,mr4 ,edward ,nairne1 and ,mr4 ,wm4 ,jones4 #dto4 #h pp4 #a plate4 7,phil4 ,trans4 lxii4 #acc47 ,london1 #aggc ,r ,c ,experiments concerning the different ,a ,s efficacy of pointed and blunted rods in securing buildings against the stroke of ,lightning4 #dto4 7,phil4 ,trans41 #aggd1 p4 #acc47 ,london1 #aggd ,r ,a ,henry1 ,j4 ,method of protecting from ,lightning buildings covered with metallic roofs4 #hvo4 7,proc4 of ,amer4 ,phil4 ,soc4 iv4 #agi47 #ahde ,r ,report concerning a letter of ,s4 ,d4 ,ingram to ,r4 ,patterson relative to the effect of ,thunder on ,telegraphic wires4 #hvo4 #i pp4 #ahdf ,s ,directions for constructing ,lightning ,washington1 7#ii7 ,rods4 #hvo4 #ahga ,c ,instructions for observations of thunderstorms4 #a p4 7,smithsonian ,institution47 ,s,hepburn1 ,j4 ,s4 ,should ,lightning ,conductors terminate in a point or in a ball8 7,proc4 ,roy4 ,scot4 ,soc4 ,arts47 ,edinburgh1 #hvo4 #ahee ,s,hericard de ,thury4 ,de l'influence des arbres sur la foudre et ses effets4 #hvo4 #ahch ,r ,herlicius1 ,d4 7,herlich1 c47 ,tractatus de fulmine et aliis impressionibus1 prodigiis et miraculis4 ,vom ,blitz1 ,donner und allerlei ,feurzeichen1 u4s4w4 #dto4 ,starg1 #afjd ,c ,s,hervieu1 ----4 ,essai sur l'lctricit ,atmosphrique4 #hvo4 #ahce ,r ,s ,highton1 ,e4 ,effects of ,atmospheric ,electricity4 #hvo4 #ahdg ,hilliard1 ,j4 ,account of ,fire from ,heaven burning the body of ,j4 ,hitchell1 of ,christchurch1 and fearfully burning the town of ,dorchester4 #dto4 ,london1 #afac ,a ,holtz1 ,w4 ,uber die ,theorie1 die ,anlage1 ,griefswald1 und die ,prfung der ,blitzableiter4 #hvo4 #ahgh ,c ,hooke1 ,r4 ,the ,posthumous works of1 containing his ,cutlerian ,lectures1 and other discoveries4 ,published by ,richard ,waller1 ,r4,s4 ,sec4 ,fol4 #egb pp4 #a plate4 ,london1 #agje ,r ,hoppe1 ,m4 ber das ,gewitter4 #dto4 #ah pp4 7,program des ,frstlich4 ,hedwigschen ,gymnasium1 in ,neustettin 444 #aj und #aa ,neustettin1 ,april #ahfe47 #ahfe ,r ,horner1 ,j4 ,k4 ,bemerkung ber ,blitzableiter u4s4w4 ,zrich1 #ahaf 7#ii7 ,s,hugueny1 ,f4 ,le coup de foudre de l'ile du ,strasbourg1 ,rhin4 #dto4 #ahfi ,r ,a ,imhof1 ,m4 ber das ,schiessen gegen heranziehende ,donner- und ,hagel-,gewitter4 7,read #bhth ,march1 #ahaa47 #dto4 #bd pp4 ,mnchen1 #ahaa ,r ,a ,theoretisch prakt4 ,anweisung zur ,anlegung der ,blitzableitern4 #hvo4 ,mnchen1 #ahaf ,s,james1 ,j4 ,o4 ,n4 ,memorandum on the ,thunderstorm which passed over ,calcutta #hth ,june1 #ahga 7,proc4 ,asiatic ,soc4 ,calcutta1 ,bengal47 #hvo4 #ahga 7#aaa7 ,s,jarriant4 ,nouveau ,paratonnerre accept par l',acadmie des ,sciences4 #hvo4 ,paris1 #ahgg 7#aae7 ,s ,etude sur les ,paratonnerres4 #hvo4 ,paris1 #ahgh 7#aag7 ,s,johnston1 ,w4 ,p4 ,report on the ,lightning ,calcutta1 ,conductors at ,dum ,dum1 ,calcutta4 #dto4 #ahgh ,jungnitz1 ,l4 ,a4 ber d4 ,erfolg4 d4 ,blitzfeuer auf d4 ,schneekoppe4 #hvo4 ,breslau1 #ahje ,r ,darstell1 d4 ,erfolgs d4 auf d4 ,schneekoppe v4 ,h4 v4 ,lindener #ahje angestellten u4 an mehreren ,orten beobachteten ,blitzfeuer4 #hvo4 ,breslau1 #ahjf 7#aad7 ,s,karsten1 ,g4 ,ueber ,blitzableiter und ,blitzschlge in ,gebude welche mit ,blitzableitern versehen waren4 #hvo4 ,kiel1 #ahgg ,s ,gemeinfatzliche ,bemerkungen ueber die ,elektricitt des ,gewitters und die ,wirkung der ,blitzableiter4 #ast edition4 #hvo4 ,kiel1 #ahgi 7#aai7 ,s #bnd ,edition4 #hvo4 ,kiel1 #ahgi ,s #crd ,edition4 #hvo4 ,kiel1 #ahhj ,r ,kirchhoff1 ,n4 ,a4 ,j4 ,zurstung1 die ,wirkung der ,gewitterwolken darzustellen4 #hvo4 7,gtt4 ,mag4 ,j4 i4 #aghj1 ,st4 ii4 ,gttingen1 pp4 #cbb-bf74 #aghj ,r ,beschreibung einer ,zurstung1 welche die anziehende ,kraft der ,erde gegen die ,gewitterwolke1 c4444 beweiset 444 nebst ,berlin1 ,nicolai1 e4 ,beschreib4 versch4444 ,maschin4 #hvo4 #ef and ,hamburg1 pp4 #a plate4 #agha ,r ,kirchmaier1 ,g4 ,c4 ,de fulmine et tonitru4 ,viteberg1 #afei ,r ,s ,kirchvogl1 ,a4 ,b4 ,de natura electr4 aere4 #hvo4 #agfg ,c ,s,klasen1 ,l4 ,die ,blitzableiter in ihrer ,construction und ,anlage4 #hvo4 #gd pp4 ,leipzig1 #ahgi ,a ,klein1 ,h4 ,j4 ,das ,gewitter und die dasselbe begleitenden ,erscheinungen4 #hvo4 ,gratz1 #ahga ,r ,klugel1 ,g4 ,s4 ,beschreib4 d4 ,wirkung1 ein4 heftig4 ,gewitters d4 #ab ,juli #aghi zu ,halle1 nebst ,erklrung d4 ,entstehung d4 ,gewitters4 #hvo4 #fd pp4 ,halle1 #aghi ,s,koenig1 ,j4 ,g4 ,de ,fulmine1 ,fulgure1 ac ,tonitru ,hiemali4 #dto4 ,norica1 #agjf ,s,krayenhoff1 ,baron4 ,handleiding tot het ,nijmegen1 stellen van ,bliksemafleiders4 #hvo4 #ahcf ,a ,krull1 ,j4 ,g4 ,versuche zur ,besttigung der ,meinung1 dass die elektrische ,materie mit der ,materie des ,donners und ,blitzes eine ,hannover1 gross ,aehnlichkeit habe4 #ageb ,r ,kuhn1 ,k4 ,g4 ,ueber ,blitzableiter4 8,in d4 ,gelehrt ,anzeigen d4 ,knigl4 bayer ,acad4 von4 #ahea u4 #aheb20 or in 8,astronom ,kalender #ahej-eb40 #ahea-b ,note4--,it seems uncertain to which this entry belongs4 ,a ,kuhn1 ,k4 ,g4 ,handbuch der angewandten ,elektricittslehre4 ,part ,i4 ,ueber ,blitzableiter4 #hvo4 ,leipzig1 #ahff ,s ,bemerkungen ueber ,blitzschlge4 #hvo4 ,munchen1 #ahfg ,s b4 d4 ,anordnung v4 ,blitzableitern1 f4 ,pulvermagazine4 ,mnch41 #ahfg ,r ,kyper 7,kieper71 ,a4 ,disp4 de fulmine quod a4 #afcf 444 turrim nitrariam aulicam ,regiomonti percussit4 #afcg ,a ,lampadius1 ,w4 ,a4 ,ueber die ,electricitt der ,atmosphre4 ,berlin1 #agic ,a ,versuche und ,beobachtungen ber ,elektricitt und ,wrme der ,atmosphre4 #hvo4 ,leipzig1 #ahje ,a ,ein ,schneegewitter und ein ,vorschlag zur ,vervollkommung der ,blitzableiter4 7,gilberts ,ann4 der ,physik1 xxix4 #eh47 #ahje ,r ,lamy1 ,f4 ,conjectures physiques sur deux colomnes 7sic7 de ,nu qui ont parus depuis quelques annes2 et sur les plus extraordinaires effets du ,tonnerre2 avec une explication de ce qui s'est dit jusqu'icy des ,trombes de mer2 et une nouvelle addition1 ou l'on verra de quelle manire le ,tonnerre tomb nouvellement sur une ,eglise de ,lagni a imprim sur une nappe d'autel une partie considrable du ,canon de la ,messe4 #abmo4 #bda pp4 #c plates4 ,paris1 #afhi ,a ,german account of the extraordinary effects of ,lightning at the ,church of ,lagni1 printed in the ,hamburg ,mag4 iii4 #bbf1 and taken from ,lamy's ,french work1 8,conjectures ,phys401 444 dated #afif1 #abmo4 is given in ,bauer1 ,abhandl4 #aggj1 p4 #afa4 ,note4--,this ,german account contains a copy of 8la partie considrable du ,canon de la ,messe10 which was found printed by lightning upon the altar-cloth1 and also of certain parts in red ink not thus reprinted4 7#acd7 ,s,lacoine1 ,e4 ,establissement de la formule relative au rayon d',action des paratonnerres 7,l',electricit1 ,october1 #ahhj47 ,paris1 #ahhj ,r ,landriani1 ,m4 ,gli effetti del ,fulmine caduto la sera del #be ,agosto1 #aghj1 nel campanile e ,monastero di ,s4 ,vincenzo al ,castello in ,milano4 #dto4 #f pp4 7,opus4 ,scelti1 iii4 #cbh47 ,milano1 #aghj ,r ,dell' utilit dei ,conduttori elettrici4 #hvo4 #cjd pp4#a plate4 ,milano1 #aghd ,abhandlung vom ,nutzen der ,blitzableiter4 ,auf ,befehl der ,guberniss herausgegeben4 ,aus dem ,italinischen von ,g4 ,muller4 #hvo4 ,wien1 #aghf ,r ,altra ricaduta del propagatore 444 ossia ultima risposta contro la difesa dei ,paragrandini4 ,lettera all' ,ateneo di ,venezia4 #hvo4 #fj pp4 ,milano1 #ahbf ,r ,langenbucher1 ,j4 ,richtige ,begriffe vom ,augsburg1 ,blitz und von ,blitzableitern4 #hvo4 #aghc ,s,langlois1 ,e4 ,h4 ,notice sur l'incendie de la ,cathdrale de ,rouen occasionn par la foudre1 le #ae ,septembre1 #ahbb4 #hvo4 ,rouen1 #ahbc 7,this ,cathedral is reported to have been struck by ,lightning in #aaaj1 #aaag1 #abhd1 #acea1 #afbe1 #afbg1 #afdb1 #agfh and #ahbb47 ,r ,lanteires1 ,j4 ,essai sur le ,tonnerre considr dans ses effets moraux sur les hommes1 et sur un coup de foudre remarquable2 suivis des notes communiques l'auteur par ,m4 le ,lausanne1 ,professeur ,saussure1 ,genve4 #hvo4 #aghi ,la ,place4 7,see ,official ,instructions1 ,france47 ,r ,a ,lapostolle4 ,trait des ,parafoudres et des ,s ,paragrles en cordes de paille4 #hvo4 #cbj pp4 c41 also #c supplements4 ,amiens1 #ahbj ,r ,trattato sul modo di preservare le abitazioni dal ,fulmine e le campagne dalla ,grandine4 ,opera volgarizzata da ,bodei4 #hvo4 #ahi pp4 #a table4 ,milano1 #ahba ,c ,ueber ,blitz-und hagelableiter an ,wiln4 u4 ,prag1 ,stroh-,seilen4 #hvo4 #ed pp4 #ahbe ,s,la ,pylaie1 ,de4 ,effets extraordinaires de la foudre4 #hvo4 #ahdi ,r ,s ,la ,rive1 ,de4 ,trait de l',electricit4 #c ,paris1 vols4 #hvo4 #ahed-eh ,r ,s ,treatise on ,electricity 7translated by ,london1 ,walker47 #c vols4 #hvo4 #ahec-eh ,r ,laroque4 ,note sur des ,eclairs de forme inusite1 observs ,toulouse pendant l'orage du #af ,juillet1 #ahej4 #hvo4 #c pp4 ,toulouse1 7,toulouse ,acad4 #c;e ,srie1 vi4 #cdi47 #ahej ,r ,lathrop1 ,dr4 ,j4 ,fatal effects of ,lightning4 ,in a letter to 444 ,joseph ,willard4 #dto4 #g pp4 7,mem4 ,amer4 ,acad4 ,charlestown1 ,old ,series1 ii4 pt4 ii4 p4 #he47 #ahjd ,r ,an account of the effects of ,lightning on the house of ,jn4 ,mason1 in ,boston1 in a letter to ,joseph ,willard4 #dto4 #d pp4 7,mem4 ,amer4 ,acad41 ,old ,series1 ii4 pt4 ,charlestown1 ii4 p4 #ia47 #ahjd ,r ,effects of ,lightning on several persons in the house of ,samuel ,cary1 of ,chelsea1 ,august #b1 #agii1 in a letter to ,john ,davis4 #dto4 #d pp4 7,mem4 ,amer4 ,cambridge1 ,acad4 ,old ,series1 iii4 pt4 i4 p4 #hb47 ,u4,s41 #ahji ,r ,effects of ,lightning on the house of ,capt4 ,d4 ,merry1 and several other houses in the vicinity1 on the evening of the #aath ,may1 #ahje1 in a letter to ,john ,davis4 #dto4 #f pp4 7,mem4 ,amer4 ,acad4 ,old ,cambridge1 ,series1 iii4 pt4 i4 p4 #hf47 ,u4,s41 #ahji ,s,laue1 ,j4 ,g4 ,de telo fulmineo4 #dto4 ,lipsi1 #agjf ,r ,lee1 ,a4 ,an ,account of the effect of ,lightning on ,two ,houses in the city of ,philadelphia1 in a letter from ,a4 ,lee to ,james ,bowdoin 7dated ,july #bi1 #agha74 #dto4 #f pp4 7,mem4 ,amer4 ,acad4 ,old ,series1 i4 ,boston1 ,u4,s41 #bdg1 part ii47 #aghe ,r ,lehaitre4 ,une instruction thor4 et prat4 sur les ,paragrles4 ,bourg1 #ahbe ,c ,s,leigh1 ,j4 ,directions for ensuring personal safety during storms1 and for the right application of ,lightning ,conductors4 #fth ,edition4 #abmo4 ,london1 #ahce8 ,r ,s ,leithead1 ,w4 ,electricity1 its nature1 operation1 and importance4 #abmo4 ,london1 #ahcg ,r ,le ,normand1 ,l4 ,s4 ,sull' utilit dei ,parafulmini e ,paragrandini per l'agricoltura4 ,seconda edizione4 #hvo4 #ai pp4 ,milano1 #ahbc ,a ,lenz4 ,sur ,combien de pieds carrs de la surface de la toiture doiton1 en construisant un ,paratonnerre1 tablir un ,conducteur terre8 ,bullet4 de la ,classe phisico-mathmatique de l',acad4 ,impriale de ,st4 ,ptersbourg1 xv4 #fc4 #ahef ,r ,le ,roy1 ,j4 ,b4 ,lettera al ,rozier su i ,parafulmini4 #dto4 #b pp4 7,scelta d',opuscoli1 ,nuova ed4 ii4 #bbb4 ,translated by ,fromond4 ,it was printed in the #abth in ed4 #aggf1 vol4 xviii4 ,the original ,french version in the ,journ4 de ,phys41 vol4 ii47 ,milano1 #aghb 7,see ,official ,instructions1 ,france47 ,r ,leschevin4 ,memoir upon a process employed in the ci-devant ,maonnais of ,france1 to avert showers of ,hail and to dissipate ,storms4 ,by ,m4 ,leschevin1 ,chief ,commissary for ,gunpowder and ,saltpetre at ,dijon4 7,from ,millin's ,magazin ,encyclopdique for #ahjf1 tom4 ii4 p4 #e74 #hvo4 #g pp4 7,in ,phil4 ,mag4 xxvi4 #bab47 ,london1 #ahjg ,r ,leslie1 ,sir ,j4 ,on the ,inefficacy of ,lightning ,conductors4 7,from ,arella1 who says that this statement appears in ,fernsac1 ,scienze fisiche matemat4 #ahbi1 p4 #acj47 #ahbi ,r ,lezay-,marnzia1 ,c4 ,f4 ,a41 ,marquis de4 ,sur les paratonnerres et les paragrles4 7,vide ,clerc47 ,s,lichtenberg1 ,g4 ,c4 ,verhaltungsregeln bey ,gttingen1 nahen ,donnerwettern4 #aggh ,r ber ,gewitterfurcht und ,gttingen1 ,blitzableitung4 #hvo4 #ahjb ,r ,a ,neueste ,geschichte der ,blitzableiter4 ,gttingen1 #hvo4 #ahjc ,r ,a ,lichtenberg1 ,g4 ,c4 ,vorschlag den ,donner auf ,noten zu se tzen #hvo4 7,lichtenberg's ,mathem4 und ,phys4 ,schriften1 c41 i4 #dgh47 ,r ,a ,versuche zur ,bestimmung der zweckmssigsten ,form der ,gewitterstangen4 ,gttingen1 #hvo4 #ahjc ,r ,a ,litchtenberg1 ,l4 ,c4 ,verhaltungsmaass regeln bey nahen ,donnerwetter nebst d4 ,mitteln sich gegen d4 schdl ,wirkungen d4 ,blitzes in ,sicherheit zu setzen4 #a ,aufl4 #hvo4 #a plate4 ,gotha1 #aggd ,r ,verhaltungsregel bey nahen ,donnerwetter2 nebst d4 ,mitteln1 sich gegen d4 schdl4 ,wirkungen d4 ,blitzes in ,sicherheit zu setzen4 #b;e ,aufl4 #agge4 #hvo4 #gh pp4 #a plate4 ,gotha1 #agge ,r ,limmer1 ,c4 ,p4 ,de ,tonitru4 ,a ,s,lining1 ,dr4 ,letter concerning his experiments of electricity with a kite4 #dto4 ,london1 #aged ,r ,linna1 ,e4 ,c4 ,vom ,blitzen der indianischen ,kresse4 #hvo4 #c pp4 7,signed ,hamburg and by ,c4 ,linnus47 ,leipzig1 #agfb ,r ,litta1 ,a4 ,a4 ,riflessioni sulla capacit de' ,conduttori elettrici esposte in una lettera al ,volta4 #dto4 #c pp4 7,opus4 ,scelti1 i4 #cdj47 ,milano1 #aggh ,r ,s ,lohmeier1 ,p4 ,de fulmine4 #dto4 ,rint1 #afgf ,a ,loomis1 ,e4 ,on the proper height of ,lightning ,rods4 7,sillimans' ,journ4 7#b71 x4 #cbj47 #ahea ,r ,lorgna1 ,a4 ,m4 ,sopra una ,fulminazione di terra4 ,lettera al ,volta4 7,verona1 #ae ,mag4 #agha47 #dto4 #g pp4 7,opus4 ,scelti1 iv4 #bce47 ,milano1 #agha ,lettera 7al ,toaldo7 sui ,parafulmini4 ,verona1 #ad ,mag4 #aggh4 7,on an insulated ,conductor for safety and for observations47 #b pp4 ,risposta 7to the above1 with the notice 8#ai ,mag4 rec40 #b pp47 7,toaldo1 ,g47 ,padua1 #ahdj 7,the above two articles are bound together with an ,address to some friends 7or ,dedication71 and signed ,gaetano dott4 ,sorgata e ,jacopo ,prof4 ,cecconi 7of #a page74 ,the whole forms a brochure1 without any proper title-page4 ,it is said in the ,dedication that the two letters were found 7in ,,ms47 in the ,biblioteca del ,seminario47 ,r ,loss1 ,p4 ,de fulmine in genere cum auctario4 7,pogg4 i4 #aejj47 ,gedani1 #afcf ,r ,lozeran du ,fech1 ,l4 ,a4 ,dissertation sur la cause et la nature du ,tonnerre et des ,eclairs4 ,et ,lettre de l',auteur ,m4 ,sarrau1 ,sc4 de l',acad4 viii4 pp4 #abmo4 ,bordeaux1 #ajj pp4 7,accad4 de ,bordeaux47 #agbf ,r ,luc1 ,j4 ,a4 ,de4 ,bemerkungen ber elektrische ,bewegungen und deren ,wirkung auf ,spitzen2 desgleichen ber ,blitz1 ,donner und die sogenannten ,wetter-,ableiter4 7,neue ,schriften der ,gesellsch4 ,naturf4 ,freunde1 ii4 #acg47 #hvo4 ,berlin4 ,r ,lucan4 ,on conducting ,lightning4 7,from ,becquerel1 ,hist47 ,r ,a ,luz1 ,j4 ,f4 ,unterricht vom ,blitze u4 v4 ,blitz u4 ,wetter ,ableitern4 #hvo4 #a plate4 ,nuremberg1 7,from ,kuhn of #ahff1 p4 #bgi47 #aghc ,r ,a ,lehrbuch d4 theor4 prakt4 ,blitzableitungslehre neu bearbeitet von ,gutle1 #ate ,theil4 #hvo4 #ahjd ,r ,a ,unterricht vom ,blitz und den ,blitz-und ,wetter ,ableitern 444 neu bearbeitet von ,nurnberg1 ,gutle4 #ast ,theil4 #hvo4 #bbj pp4 #a plate4 #ahjd ,r ,lyon1 ,j4 ,account of several new and interesting phnomena discovered in examining the bodies of a man and four horses killed by ,lightning near ,dover4 #hvo4 ,london1 #agif ,r ,a ,macfait1 ,e4 ,observations on ,thunder and ,electricity 7,essays and ,obs4 ,phys4 and ,edinburgh1 ,lit4 ,vol4 #a1 p4 #ahi4 #hvo47 #aged ,c ,s ,mc,gregor1 ,w4 ,protection of ,life and 7#ajf7 ,property from ,lightning4 #hvo4 ,bedford1 #ahge ,a ,maffei1 ,f ,s4 ,delle formazione dei ,fulmini4 #dto4 ,verona1 #agdg ,r ,maffioli di ,udine4 ,on ,lightning ,conductors4 7,giornale d',italia1 #be ,agosto1 #aggj47 #aggj ,r ,magnin1 ,a4 ,le feu du ciel1 histoire de l'lectricit et de ses principales applications4 ,ides des anciens1 premires observations1 machine lctrique1 bouteille de ,leide1 paratonnerre1 c4 #c;e dition4 #hvo4 #bdj pp4 ,tours1 #ahff ,r ,magrini4 ,l4 ,sopra un metodo di togliere alle nubi maggiore copia di elettricit che coll ordinario parafulmine4 ,nota letta #be ,agost1 #ahei4 #dto4 #c pp4 ,milano1 #ahfj ,r ,sulla meteora che nella sera del #d ,marzo1 #ahfa1 colpiva la cattedrale di ,milano2 e sulla riforma de' suoi ,parafulmini4 ,memoria4 #dto4 #aa p4 ,milano1 #ahfa ,s ,sulla elettricita atmosferica4 #dto4 ,milan1 #ahfc ,r ,s ,mahon1 ,viscount4 ,principles of ,electricity4 #dto4 #aggi ,r ,mairan1 ,j4 ,j4 d',o4 de4 ,sur les effets de la chute du ,tonnerre sur un arbre4 #dto4 7,mm4 ,par4 #agbd47 ,paris1 #agbd ,c ,s ,majendie1 ,v4 ,d4 ,report on the destruction 7#gd7 by ,lightning of a ,gunpowder store4 fcp4 fol4 7,official ,report--unpublished47 ,london ,r ,majocchi1 ,g4 ,a4 ,istruzione teorica e pratica sui ,parafulmini4 #hvo4 #aad pp4 #a plate4 ,milano1 #ahbf ,c ,majoli ,simonis4 ,hoc est colloquia physica noua et admiranda tum lectu incunda et supra fidem recreabilia tum cognitu1 insignia et penitus necessaria4 ,fol4 #adbh ,mogunti1 pp4 and ,index4 #afbe ,r ,mako 7von ,kerek ,gede71 ,p4 ,dissertatio physica de natura1 et remediis ,fulminum4 #hvo4 #ajj pp4 ,goriti1 #aggc ,r ,a ,mako1 ,p4 und ,retzer4 ,physikalische ,s ,abhandlung von den ,eigenschaften des ,donners1 und den ,mitteln wider das ,einschlagen4 ,verfaszt von ,p4 ,mako und von ,j4 ,e4 von ,retzer in das ,deutsche bersetzt4 #ast ed4 #hvo4 #abe pp4 #a plate4 ,wien1 #aggb ,r ,physikalische ,abhandlung von den ,eigenschaften des ,donners1 u4 d4 ,mitteln wider das ,einschlagen4 ,verfaszt von ,p4 ,mako1 und von ,j4 ,e4 ,retzer1 in das ,deutsch1 bersetzt4 #bte ,aufl4 7,von ,retzer aus d4 latein ,orig4 das erst4 #aggc erschien47 ,wien1 #agge ,c ,a ,mann1 ,r4 ,j41 ,m4,d4 ,the ,protection of ,s ,buildings from ,lightning4 7,journal of 7#ajh7 ,society of ,arts47 #hvo4 ,london1 #ahge 7#aca7,s ,remarks on some practical points connected with the construction of ,lightning ,conductors4 7,quarterly ,journal of the ,meteorological ,society47 #hvo4 ,london1 #ahge ,r ,marini1 ,p4 ,relazione ,memoria sul ,fulmine caduto in ,brescia nella torre della ,paletta #ahjc1 e ,sul ,parafulmine costrutto sopra al palazzo della ,loggia da lui #ahje4 #hvo4 7,comment4 dell' ,accad4444 del ,dipartimento del ,mella1 tom4 i4 ,elenco delle ,memorie47 ,brescia1 #ahjh ,r ,marsault1 ,j4 ,p4 ,l4 ,electro-calorique1 ou les ,paratonnerres rforms 444 o l'on trouve un nouveau plan de paratonnerre1 etc4 #ahmo4 #gf pp4 ,niort1 #aheb ,r ,martin4 ,mmoire sur un coup de ,tonnerre qui a clat dans l',eglise de ,st4 ,nicolas de ,toulouse 444 #ag ,march1 #aghg4 #dto4 #i pp4 7,toulouse ,acad4 #are srie1 iv4 ,toulouse1 #ajj47 #agij ,c ,s,martin1 ,t4 ,h4 ,la foudre1 l'lectricit et le magntisme chez les anciens4 #abmo4 ,paris1 #ahff ,r ,a ,marum1 ,m4 van4 ,verhandeling over het ,groningen1 ,electrizeeren4 #hvo4 #aggf ,r ,sur les paratonnerres4 #dto4 7,jour4 ,phys4 #aghg1 xxxi47 ,paris1 #aghg ,r ,marzari1 ,g4 ,on ,conductors for ,lightning4 ,account of his ,admonitions1 c4 7,treviso ,padova1 ,athenum1 vol4 ii4 p4 #gc7 7#ahcb87 ,r 7or ,anon47 ,maniera pratica di fare li conduttori ai campanili1 alle chiese1 ed alle case1 descritta per uso dei fabbri1 falegnami1 e muratori1 c4444 stampata per ordine del ,magistrato ,excell4 ,alla ,sanit4 #dto4 #cg pp4 ,venezia1 #aghg ,r ,mawgridge1 ,r4 ,a4444 relation of the 444 effects of an unusual clap of ,thunder and ,lightning4 #dto4 #b pp4 7,phil4 ,trans4 xix4 for #afie-f-g1 p4 #ghb47 ,london1 #afih ,r ,maxwell1 ,h4 ,observations on ,trees as ,conductors of ,lightning4 ,communication dated ,june #ba1 #aghg4 #dto4 #b pp4 7,mem4 ,amer4 ,acad4 old series1 ii4 part i4 p4 ,boston1 ,u4,s41 #adc47 #agic ,c ,s ,maxwell1 ,prof4 ,j4 ,clerk4 ,on the 7#aji7 protection of buildings from ,lightning4 #hvo4 7,british ,association ,report7 ,london1 #ahgg ,r ,may1 ,w4 ,verhall der uitwerkinge van eenen enkelden blixemslag1 voorgevallen op een van's lands oorlogscheepen1 in het jaar #agdi4 7,verhandel4 van het ,maatsch4 te ,haarlem1 xii4 #cia47 ,haarlem ,r ,mayr1 ,g4 ,abhandlung b4 ,elektricitt und sichernde ,blitz-,ableiter fr jedes ,gebude fr ,reise-u4 ,frachtwagen1 ,schiffe1 ,bume u4 ,denkmler4 ,nebst e4 ,anh4 ber ,hagel-,ableiter4 ,geprft 7#b ,aufl47 neu4 u4 verbess4 #abmo4 ,mnchen1 #ahci ,r ,melandri1 ,g4 ,disquisizione sui ,paragrandini4 ,letta nell' ,ateneo di ,treviso il #ae ,dec4 #ahbe4 #dto4 #bf pp4 7,inserita nel vol4 x4 del ,gle4 sulle ,scienze 444 delle provincie ,venete47 ,treviso1 #ahbf ,r ,considerazioni critiche sopra l'efficacia del ,paragrandine metallico 444 #hvo4 #cg pp4 ,firenze1 #ahbg ,a ,s ,melsens1 ,l4 ,f4 ,h4 ,notes sur les ,bruxelles1 7#adj7 ,paratonnerres 7,nos4 #a-e74 #hvo4 #ahfe-gh ,a ,s ,notice sur le coup de foudre de la ,bruxelles1 7#acg7 gare d',anvers4 #hvo4 #ahge ,a ,s ,des paratonnerres pointes1 7#ach7 conducteurs et raccordements terrestres ,bruxelles1 multiples4 ,large #hvo4 #ahgg ,s ,communication verbale4 #hvo4 7,see ,bruxelles1 ,bourges74 #ahgg ,r ,c ,meredith4 ,considerations on the utility ,s of ,conductors 444 #hvo4 #a plate4 ,london1 #aghi ,r ,mermet1 ,a4 ,c4 ,memoir on ,lightning ,conductors4 ,prize question1 ,bordeaux ,bordeaux1 ,academy4 #hvo4 #ahcg ,r ,metterkamp1 ,d4 ,c4 ber ,blitzableitungen1 gegen ,busse's ,theorie4 #hvo4 ,leipsig1 #ahab ,r ,a ,meurer1 ,h4 ,abhandl4 v4 d4 ,blitze u4 d4 ,verwahrungsmitteln dag4 #dto4 ,trier1 #agia ,r ,michaelis4 ,briefwechsel zwischen ,michaelis und ,lichtenberg ber die ,absicht oder ,folgen der ,spitzen auf ,salomon's ,tempel4 #hvo4 7,gtingischer ,gttingen1 ,mag4 #c;e anne47 #aghc ,note4--,martin says that this is also in ,g4 ,c4 ,lichtenberg's ,physikalische und ,mathem4 ,schriften1 tom4 iii4 p4 #bea-cja4 ,gttingen1 #ahjc1 in #abmo41 7,vermischte ,schriften1 #ahjj-ahje4 #i vols4 #abmo4 ,gotha47 ,r ,michaelis und ,lichtenburg4 ,briefwechsel ber die ,absicht oder ,folgen der ,spitzen auf ,salomon's ,tempel1 #aghc4 #hvo4 7,lichtenberg's ,math4 und ,phys4 ,schriften iii4 #bea1 and in ,gtt4 ,mag4 ,gttingen1 i4 iii41 7#ahgc71 ,st4 v4p4 #gce-fh47 #ahjd ,michel1 ,f4 7,see ,official ,instructions1 ,france74 ,s,mittelstrass4 ,die ,blitzableiter nach den neuesten ,erfahrungen zweckmssigster ,magdeburg1 ,construction4 #hvo4 #ahga 7#ajf7 ,s,mohn1 ,h4 ,lynildens farlighed i ,norge4 ,kristiania1 #dto4 #ahge ,s,monnet1 ,p4 ,a4 ,nouveau procd pour tudier l'lectricit atmosphrique4 #hvo4 ,lyon1 #ahfe ,r ,mountaine1 ,w4 ,an account of some extraordinary effects of ,lightning1 ,july #af1 #agei1 with some remarks by ,gowin ,knight4 #dto4 7,phil4 ,trans4 an4 #agei1 p4 #bid47 ,london1 #agei ,r ,muller1 ,c4 ,h4 ber ,lapostolle's ,blitzableiter4 #hvo4 7,gilb4 ,ann4 lxviii4 #ahba47 ,leipzig1 #ahba ,r ,murray1 ,j4 ,on a singular effect produced by ,lightning4 #hvo4 #b pp4 7,phil4 ,mag4 lx4 #fa47 ,london1 #ahbb ,c ,s ,a ,treatise on ,atmospherical 7#hb7 ,electricity4 #hvo4 ,london1 #ahcj ,r ,s ,the ,description of a new ,lightning ,conductor4 #hvo4 #a plate4 #fc pp4 ,london1 #ahcc ,r ,a ,lightning ,conductors4 #hvo4 #b pp4 7,annals of ,electricity1 vii4 #hb47 ,london1 #ahda ,c ,murray1 ,j4 ,electricit atmospherique comprenant les instructions ncessaire pour tablir les paratonnerres et les paragrles4 ,traduit de l',anglais4 ,sm4 #hvo4 #bfd pp4 ,paris1 #ahgg ,a ,murray1 ,n4 ,treatise on ,atmospheric ,electricity1 including observations on ,lightning ,rods4 #hvo4 ,london1 #ahbh ,r ,a ,mylius1 ,c4 ,nachrichten und ,gedanken von der ,elektricitt des ,donners4 #hvo4 ,berlin1 #ageb ,r ,a ,nairne1 ,e4 ,experiments on ,electricity1 being an attempt to show the advantage of elevated pointed ,conductors4 ,read at the ,royal ,society1 ,june #ahth and #beth1 #aggh4 #dto4 #dj pp4 #d plates4 7,phil4 ,trans4 #aggh1 p4 #hbc47 ,london1 #aggi ,r ,an account of the effect of ,electricity in shortening ,wires4 #dto4 7,phil4 ,trans4 #aghj1 p4 #ccd47 ,london1 #aghj ,r ,letter--containing an account of ,wire being shortened by ,lightning4 #dto4 7,phil4 ,trans4 #aghc1 p4 #bbc47 ,london1 #aghc ,r ,nauwerck1 ,c4 ,l4 ,versuche neuer ,erklrung u4 ,folge der jetzigen ,witterung auf ,oekonomie anwendbar1 mit meteorolog4 ,bemerkk4 die ,gewitterableiter betreffend4 ,dresden u4 #hvo4 ,leipzig1 #aghg ,r ,needham1 ,j4 ,t4 ,recherches sur la question si le son des cloches pendant les orages fait clater la foudre en la faisant descendre sur le clocher1 etc4 7,mm4 de ,bruxelles1 ,brux4 iv41 #aghc47 #aghc ,r ,neeff1 ,c4 ,e4 ,beschreib4 u4 ,anwend4 d4 ,blitzrades4 #hvo4 7,poggend4 ,ann4 xxxvi41 #ahce47 ,leipzig1 #ahce ,a ,newall1 ,r4 ,s4 ,lightning ,conductors3 their use as protectors of buildings1 and how to apply them4 #hvo4 ,london1 #ahgf ,a ,nippoldt1 ,dr4 ,dimensions of ,lightning ,rods4 7,telegraphic ,journal1 vi4 #gh47 #ahgh ,r ,a ,nollet1 ,j4 ,a4 ,mmoire sur les effets du ,tonnerre compars ceux de l',electricit avec quelques considrations sur les moyens de se garantir des premiers4 #dto4 7,mm4 de ,paris1 an4 #agfd1 ,hist4 p4 #a1 ,mm4 p4 #djh47 ,paris1 #agfd ,s ,vergleichung der ,wrkungen des ,donners mit dem ,wrkungen der ,electricitt4 7,mm4 de ,paris1 #agfd47 #hvo4 ,prag1 #agfi ,r ,oliver1 ,a4 7,salem74 ,a ,theory of ,lightning and ,thunder ,storms4 #dto4 #bh pp4 7,trans4 ,philadelphia1 ,amer4 ,phil4 ,soc4 ,old ,series1 ii4 p4 #gd47 #aghf ,r ,orliaguet1 ,m4 ,essai sur le paratonnerre ,limoges et et le paragrle4 #hvo4 #ai pp4 ,paris1 #ahfe ,r ,ostertag1 ,j4 ,p4 ,prgrm4 von d4 ,blitzableitern4 #dto4 7,from ,pogg4 ii4 ,regensburg1 #ccg47 #agha ,r ,pasumot1 ,fra4 ,observations sur les effets de la foudre dans une maison de ,paris4 #aghd ,r ,patterson1 ,r4 ,an improvement on ,metallic ,conductors1 or ,lightning ,rods3 in a letter to ,d4 ,rittenhouse1 honoured with the ,magallanic ,premium 444 ,dec41 #agib4 ,read ,nov4 #e1 #agij4 #dto4 #d pp4 7,trans4 ,amer4 ,phil4 ,soc41 ,old ,series1 vol4 iii4 ,philadelphia1 #cba47 #agic ,s,peck1 ,f4 ,desiderata ,curiosa1 vol4 ii41 folio 7contains1 8,surprizing effect of ,lightning at ,barton1 ,notts407 #agce ,r ,pelison4 ,blitzfanger4 7,abhandl4 d4 naturforsch4 ,gesells4 zu ,berlin v ,jahr #agib1 x47 ,c ,peltier1 ,j4 ,c4 ,a4 ,recherches sur la cause des phnomnes lectrique e l'atmosphre1 etc4 #hvo4 #di pp4 7,annales de ,chimie47 ,paris1 #ahdb ,c ,an enquiry into the cause of the ,electric phenomena of the atmosphere1 etc4 #hvo4 #ch pp4 7,taylor's ,scientific ,memoirs1 vol4 iii47 ,london1 #ahdb ,s ,sur le trombe de ,monville 7clivage des arbres par la foudre74 #dto4 ,rouen1 #ahde ,s ,notice sur la ,foudre4 #hvo4 ,paris1 #ahde ,r ,perego1 ,a4 ,relazione sul ,fulmine caduto in ,iseo1 il #ag ,mag4 #ahcc4 7,comment4 ,ateneo ,brescia1 vol4 printed in #ahcd pro #ahcc47 ,brescia1 #ahcd ,r ,descrizione dei danni cagionati dalla caduta di un fulmine in ,mompiano provincia di ,brescia4 ,s,perrin1 ,p4 ,etude sur les ,eclairs4 #hvo4 ,paris1 #ahgc ,r ,a ,pfaff1 ,c4 ,h4 ber ,blitz und ,blitzableiter4 #hvo4 7,gehler's ,phys4 ,wrterbuch neu bearb47 ,leipzig1 #ahbe 7#ih7 ,s,phillips1 ,r4 ,on atmospheric electricity4 #hvo4 ,london1 #ahfc ,c,phin1 ,j4 ,plain directions for the ,a,s construction and erection of ,lightning ,new ,york1 7#ajb7 ,rods4 #bnd ,edition4 #abmo4 #ahgc ,s,phipson1 ,t4 ,l4 ,familiar ,lectures--,lightning ,points4 #hvo4 ,r ,pickel1 ,g4 ,abhandl4 ber ,blitzableiter1 u4s4w4 7,from ,poggendorff1 ii4 #ddd47 #ahba ,r ,pilatre de ,rozier4 ,sur la cause de la ,foudre4 7,journ4 ,phys4 xvi4 #aghj47 ,paris1 #aghj ,r ,pilkington1 ,j4 7,bishop of ,durham74 ,the ,burning of ,st4 ,paul's ,church in ,london in #aefa1 on the #dth ,june1 by ,lightning4 #hvo4 ,london1 #aefa8 ,r ,a ,plieninger1 ,dr4 ber die ,blitzableiter1 ,s ihre ,vereinfachung und die ,verminderung ihrer ,kosten4 ,nebst einem ,anhang ber das,verhalten der ,menschen bei ,gewittern4 ,eine gemeinfassliche ,belehrung fr die ,verfertiger der ,blitzableiter1 sowie fr die ,hausbesitzer4 ,im ,auftrage der k4 ,centralstelle des landwirthschaftlichen ,vereins in ,wrttemberg4 #hvo4 #aad pp4 #c ,stuttgart1 plates4 #ahce ,c ,pliny1 ,c4 ,the historie of the ,world1 commonly called the ,naturall ,historie of ,c4 ,plinius secundus4 ,translated into ,english by ,philemon ,holland4 ,fol4 ,london1 #afcd ,r ,poy1 ,a4 ,sur les temptes lectriques et la quantit de victimes que la foudre fait annuellement aux ,etats-,unis ,versailles1 d',amrique et l'le de ,cuba4 #hvo4 #ahee ,s ,des caractres physiques des clairs en boules4 #hvo4 ,paris1 #ahee ,r ,c ,analyse des hypothses 444 ,eclairs ,versailles1 ,s sans tonnerre4 ,large #hvo4 #ahef ,s ,sur les nombres de personnes tues par la foudre dans le ,royaume de ,grande-,bretagne1 de #aheb #ahef1 compar aux dcs par fulguration en ,france et dans d'autres parties du globe4 #dto4 ,paris1 #aheh ,s ,sur les clairs sans tonnerre observs la ,havanne1 pendant l'ann #ahei4 #hvo4 ,paris1 #ahfj ,r,c ,relation ,historique et theorie des ,s images ,photo-,electriques de la ,foudre4 #bnd ,ed4 #abmo4 ,paris1 #ahfa ,poisson4 7,see ,official ,instructions1 ,france47 ,r ,pollini4 ,sul passaggio del ,fulmine che nel 444 #f ,agosto1 #agie 444 scoppi nel 444 ,tempio di ,s4 ,andrea in ,vercelli1 e ,vercelli1 sugli effetti4 #hvo4 #agif ,r,c ,poncelet1 ,m4 ,la ,nature dans la formation ,a ,s du ,tonnerre4 #hvo4 ,paris1 #agff ,c ,pontano1 ,j4 ,j4 ,liber de meteoris4 ,sm4 #hvo4 #bbe pp4 #aede ,r ,poppe1 ,joh4 ,h4 ,m4 ,gewitterbchlein zum ,schutz und zur ,sicherheit gegen d4 ,gefahren der ,gewitter1 besond4 auch b4 d4 ,kunst1 ,blitzableiter auf d4 beste ,art ,tubingen1 anzulegen4 #hvo4 #ahcj ,a ,porro4 ,substitution d'un ,tube de ,plomb la ,corde mtallique communment employ comme ,conducteur pour les ,parontonnerres4 7,compt4 ,rend4 xxx4 #hf47 #ahej ,r ,a ,pouillet1 ,c4 ,s4 ,m4 ,elments de ,physique ,s exprimentale4 #gth ,ed4 #b vols4 #hvo4 ,paris1 #ahef 7,see ,official ,instructions1 ,france47 ,a ,s ,preece1 ,w4 ,h4 ,on ,lightning and ,lightning 7#ajj7 ,conductors4 7,jour4 ,soc4 ,tel4 ,eng47 #hvo4 ,london1 #ahgc 7#acb7 ,s ,on the proper form of ,lightning ,conductors4 7,brit4 ,ass4 ,rep41 #ahhj47 ,london1 #ahhj 7#ace7 ,s ,on the space protected by a ,lightning ,conductor4 7,phil4 ,mag41 ,dec4 #ahhj47 #hvo4 #d pp4 #a plate4 ,london1 #ahhj ,r ,preibsch1 ,c4 ber ,blitzstrahlableiter4 #cb pp4 #a plate4 ,leipzig1 #ahbe ,r ,a ber ,blitzstrahlableiter1 deren ,nutzbarkeit und ,anlegung4 #bnd ,edition enlarged1 c4 7#c ,b47 #hvo4 #df pp4 ,leipzig1 #ahcj ,r ,s ,priestley1 ,j4 ,history of the present state of ,electricity4 #bnd ,ed4 #dto4 ,london1 #agfi ,r ,putnam1 ,a4 ,remarks on ,l4 ,baldwin's proposed improvement in ,lightning ,rods1 in a letter to ,jed4 ,morse4 ,article dated ,january #ab1 #agii4 #dto4 #f pp4 7,mems4 ,amer4 ,acad4 ,old ,series1 ii4 part ii4 p4 ,charlestown1 #ii47 #ahjd ,r ,s ,quatrefages1 ,a4 de4 ,action de la ,foudre ,toulouse1 sur des tres organiss4 #hvo4 #ahcg ,r ,quinquet4 ,observations sur les ,paratonnerres4 7,journal de la ,socit des ,pharmaciens de ,paris1 tom4 i4 p4 i4 #ajj47 ,r ,racagni1 ,g4 ,m4 ,sopra alcuni conduttori elettrici che sono stati percossi dal fulmine4 ,memoria4 ,ricevuta #ac ,luglio1 #ahah4 #dto4 #ad pp4 7,mem4 della ,soc4 ,ital4 xviii4 #aci47 ,modena1 #ahbj ,r ,sopra1 alcuni edifizii muniti di ,parafulmini ,frankliniani stati dal ,fulmine danneggiati4 ,memoria4 ,ricevuta #aj ,nov4 #ahba4 #dto4 #bf pp4 #a plate4 7,ital4 ,soc4 ,mem4 xix4 p4 #a47 ,modena1 #ahbc ,r ,raven4 ,account from ,carolina of the effects of ,lightning on two of the rods affixed to houses for securing them against ,lightning4 ,r ,s ,read1 ,j4 ,a summary view of the spontaneous electricity of the earth and atmosphere4 #hvo4 ,london1 #agic ,s,redars1 ,c4 ,histoire abrge du tonnerre4 #dto4 ,avignon1#ahec ,r ,s ,r7dars71 ,c4 ,nouveaux appareils contre les dangers de la foudre4 #hvo4 ,paris1 #ahdf ,c ,regii1 ,h4 ,philosophia ,naturalis4 ,editio ,amstelodami1 secunda4 #dto4 #ddb pp4 #afed ,r ,reich1 ,f4 ber d4 ,wirk4 einiger ,blitzschlge in ,freiberger ,gruben4 #hvo4 7,pogg4 ,ann4 lxv4 #ahde47 ,leipsig1 #ahde ,r ,a ,reimarus1 ,j4 ,a4 ,h4 ,die ,ursache des ,einschlagens vom ,blitze u4 dessen natrl4 ,abwend1 von unseren ,gebuden1 aus zuverlssigen ,erfahrungen von ,wetterschlgen vor ,augen gelegt4 #hvo4 #abh ,langensalsa1 pp4 #agfi ,ursache v4 ,einschlagen des ,blitzes4 #hvo4 ,leipzig1 #aggd ,r ,s ,vorschriften zur ,anlegung einer ,blitz-,ableitung an allerley ,gebuden nach zuverlssigen ,erfahrungen4 #hvo4 #bd pp4 ,hamburg1 #aggh ,r ,a ,vom ,blitze3 i4 ,dessen ,bahn u4 ,wirk4 ,s auf versch4 ,krper1 c4 #hvo4 #fgh pp4 ,hamburg1 #aggh ,r ,nachricht von einer ,zurstung1 welche die ,wirkung der ,gewitterwolke sinnlich darstelt4 7,deutsch4 ,mus4 ,oct4 #aggi1 p4 #cbi4 f47 #aggi ,r ,reimarus1 ,j4 ,a4 ,h4 ,einige gegen d4 ,blitzableitung gemachte ,einwrfe ,frankf4-a4-,m41 beantwortet4 #hvo4 #agij ,r ,s ,neuere ,bemerkungen vom ,blitze dessen ,bahn1 ,wirkung1 sichern und bequemen ,ableitung1 c4 #hvo4 #chf pp4 #i plates4 ,hamburg1 #agid ,r ,a ,ausfhrliche ,vorschriften1 c4 #hvo4 ,hamburg1 #agid ,r ,ausfhrliche ,vorschr4 z4 ,blitzableitung an allerley ,gebuden4 #hvo4 #df pp4 #b plates4 ,hamburg1 #agig ,r ber ,blitzschlge u4 ,blitzableiter4 #hvo4 7,gilb4 ,ann4 vi4 ix4 u4 xxxvi47 ,leipzig ,a ,ueber die ,sicherung durch ,blitzableiter4 7,gilbert's ,ann4 xxxvi4 #aac47 #ahaj ,c ,s,reinzer1 ,f4 ,meteorologia ,august ,philosophico-politica in duodecim ,vindelicorum1 dissertationes1 c4 ,fol4 #big pp4 #agji ,s,reussius1 ,j4 ,a4 ,de ,fulmine4 #dto4 ,rinthelii1 #afgf ,r ,s ,ribbentrop1 ,h4 ,g4 ,f4 ber die ,blitzrhren oder ,fulguriten und besonders ber das ,vorkommen ders4 am ,regensteine bei ,blankenburg4 #hvo4 #df pp4 #a plate4 ,braunschweig1 7,schweigger1 ,journ4 lvii4 #ahbi47 #ahcj ,r ,richardot1 ,c4 ,nouveaux appareils contre le danger de la ,foudre et le flau de la ,grle4 #hvo4 #dd pp4 ,paris1 #ahbe ,r ,nuovo sistema di apparecchi contro i pericoli de ,fulmine ed il flagello della ,grandine4 ,trad4 dal ,francese4 #hvo4 #de pp4 ,indice e ,lettera4 ,milano1 #ahbg ,r ,rittenhouse and ,hopkinson4 ,an account of the effects of a ,stroke of ,lightning on a house furnished with ,two ,conductors2 in a letter 444 to ,mr4 ,r4 ,patterson4 ,read ,oct4 #ae1 #agij4 #dto4 #d pp4 7,trans4 ,amer4 ,philadelphia1 ,phil4 ,soc4 ,old ,series1 vol4 iii47 #agic ,r ,rittenhouse and ,jones4 ,account of several ,houses in ,philadelphia struck by lightning1 ,june #gth1 #aghi4 ,read ,july #ag1 #aghi4 #dto4 #d pp4 #a plate4 7,trans4 ,amer4 ,phil4 ,soc4 ,old ,series1 vol4 iii4 p4 ,philadelphia1 #aai47 #agic ,a ,roberts1 ,m4 ,on ,lightning ,conductors1 particularly as applied to vessels4 #b vols4 #hvo4 ,london1 #ahcg ,robespierre4 ,un ,plaidoyer prononc dans une cause relative un ,paratonnerre4 #hvo4 7,from ,marget1 ,etude sur les travaux de ,romas1 page #hj--not the exact title47 #aghc8 ,a ,romas1 ,j4 de4 ,neuer elektr4 ,versuch mit dem fliegenden ,drachen am1 #ad ,nov41 #agec #agec ,r ,s ,mmoire sur les moyens de se garantir de la ,foudre dans les maisons2 suivi d'une ,lettre sur l'invention du ,cerf volant lectrique1 avec les pices justificatives de cette mme lettre4 ,bordeaux1 #abmo4 #aef pp4 #b plates4 #aggf ,the ,pices ,justicatives contain testimonials1 a certificate of the ,bordeaux ,acad41 c41 which prove that he had invented 7imagin7 7but had not used7 the ,electrical ,kite on the #abth ,july1 #ageb4 ,merget1 ,etude sur les travaux de ,romas1 imputes to ,franklin 7by implication7 the possibility of having derived the idea from ,romas3 without foundation1 ,i think4--,f4,r4 ,r,c ,ronalds1 ,sir ,f4 ,catalogue of books and ,s papers relating to ,electricity1 c4 ,compiled by ,sir ,f4 ,ronalds1 ,f4,r4,s41 and published by the ,society of ,telegraph ,engineers4 #hvo4 xxvii4 #efd pp4 ,london1 #ahhj ,s,runnels1 ,j4 ,specimen inaugurale de causa fulminis et tonitru4 #dto4 ,leyde1 #agei ,r ,sage1 ,b4 ,g4 ,observations sur les ,paratonnerres4 #hvo4 ,paris1 #ahjh ,r ,recueil historique d',effets ,fulminaires4 #hvo4 #ba pp4 ,paris1 #ahbb ,st4 ,lazare4 7,see ,bartholon de ,st4 ,lazare47 ,r ,a ,saussure1 ,h4 ,b4 de4 ,manifeste1 ou exposition abrege1 de l',utilit des ,conducteurs lectriques4 #hvo4 ,genve1 #agga ,r ,scaramelli1 ,il ,paragrandinatore istruito sull' arte e sugli usi dei paragrandini e parafulmini alla ,tholard4 #hvo4 #bj pp4 #b plates4 ,venezia1 #ahbd ,r ,s ,schaffrath1 ,l4 ,de electricitate coelesti4 #dto4 ,pestini1 #aggh ,r ,scheibel1 ,g4 ,e4 ,d4 d4 ,blitz in ,pulverthurm verunglckte ,breslau4 #dto4 7,from ,heinsius47 ,breslau1 #agej ,r ,scheibel1 ,j4 ,e4 ,einige ,progr4 b4 den a4 d4 ,elisabetkirche zu ,breslau erricht4 ,blitzableiter4 #agic-d ,r ,s ,schieck1 ,dr4 ,ueber atmosphrische ,oldenburg1 ,electricitt4 #hvo4 #ahgj ,c ,schnbein1 ,c4 ,f4 ,on some secondary physiological effects produced by ,atmospheric ,electricity4 #hvo4 ,london1 #ahea ,c ,schwartz1 ,f4 ,wolken und ,wind1 ,blitz und ,donner4 #hvo4 #cjg pp4 ,berlin1 #ahgi ,r ,scoresby1 ,dr4 ,w4 ,on the singular effects of ,two ,strokes of ,lightning upon a ,vessel4 #hvo4 7,brewster's ,journal of ,science1 viii4 #ahbh47 #ahbh ,r ,scudery1 ,d4 ,j4 ,fernglas d4 ,artzney wissenschaft4 nebst ,abhdl4 ,schiffe und ,huser v4 d4 ,blitz zu verwahren a4 d4 ,mnster1 #aggd ,italianen4 #hvo4 or #agge ,s,secchi1 ,a4 ,di alcuni fenomeni accadute nella scarica di un fulmine in ,alatri4 #dto4 ,rome1 #ahgb ,r ,s ,sestier1 ,f4 et ,mhu1 ,c4 ,de la ,foudre1 de ses formes et de ses effets sur l'homme1 les animaux1 les vgtaux et les corps bruts2 des moyens de s'en prserver1 et des paratonnerres par ,f4 ,sestier4 ,rdig sur les documents laisss 444 et complt par ,c4 ,mhu4 #b vols4 #hvo4 ,paris1 #ahff ,r ,s ,sidney1 ,e4 ,electricity1 its phenomena and results4 #afmo4 ,london1 #ahdc ,r ,a ,sigaud de la ,fond1 ,m4 ,prcis historique et exprimental des ,phnomnes lectriques4 #bnd ed4 #hvo4 ,paris1 #aghe ,r ,c ,simmons1 ,j4 ,an essay on the cause of ,s lightning4 #hvo4 ,rochester1 7#ha7 #agge ,r ,spallanzani1 ,l4 ,lettera al ,barletti 444 sopra un fulmine ascendente4 #dto4 #e pp4 7,opusc4 ,scelti4 xiv4 #bif47 ,milano1 #agia ,c,a ,spang1 ,h4 ,w4 ,a ,practical ,treatise on ,s ,lightning ,protection4 #hvo4 ,philadelphia1 7#aab7 #ahgg ,a ,sprague1 ,j4 ,f4 ,electricity3 its ,theory1 ,sources and ,applications4 #hvo4 ,london1 #ahge ,r ,sternberg1 ,joachim ,graf von4 ,beobachtungen ber die ,bildung der ,donner-,wolken und ,entstehung der ,donner-,wetter4 7,mayer's ,samml4 ,phys4 ,aufs4 des ,bhmischen ,naturf4 iii4 p4 #a47 ,prag1 #agib ,r ,stoikowich1 ,a4 ,schutzmittel wider d4 ,petersburg8 ,blitz4 #ahaj ,r ber ,blitzableiter4 ,petersburg8 #ahbf ,r ,stoll1 ,j4 ,j4 ,beleuchtung einiger ,vorurtheile in ,ansehung der ,donnerwetter und ,blitzableiter4 #hvo4 ,lindau1 #agij 7#acj7 ,stotherd1 ,col4 ,earth connections of ,lightning ,conductors4 #hvo4 ,london1 #ahge ,a ,stricker4 ,ueber ,anwendung des ,galvanismus zur ,prfung der ,blitzableiter4 7,pogg4 ,ann41 lxix4 #eed4 ,polyt4 ,journ4 ciii4 #bfe47 #ahdf ,a ,s,stricker1 ,w4 ,der ,blitz und seine ,wirkungen4 #hvo4 ,berlin1 #ahgb ,r ,s ,sturgeon4 ,annals of ,electricity4 #aj vols4 #hvo4 #ahcf ,r ,s ,recent ,experimental researches on ,electricity4 #hvo4 ,london1 #ahcj ,a ,sturgeon1 ,w4 ,on ,lightning and ,lightning ,conductors4 7,mem4 of the ,manch4 ,soc4 ,manchester1 7#b71 ix4 #ef47 #ahea ,r ,a ,tavernier1 ,a4 de4 ,blitzableiter1 genannt ,s ,antijupiter oder ,tavernier's gewitter-ableitende ,sule4 #hvo4 ,leipzig1 #ahcc ,r ,s ,tedeschi1 ,a4 ,grundl4 u4 auf mehrfahr1 beruh4 ,anleit z4 ,verfert4 u4 ,erricht1 d4 ,tholardschen ,blitz- u4 ,hagel-,ableiter u4s4w4 nach d4 ,ital4 m4 e4 ,anh4 #hvo4 #cj pp4 #a plate4 ,prag1 #ahbe ,s,tessier4 ,observation sur l'effet du tonnerre ,rambouillet4 #dto4 ,paris1 #aghe ,r ,a ,tetens1 ,j4 ,n4 b4 d4 beste ,sicherung ,btzow and ,s einer ,person bey einem ,gewitter4 #hvo4 ,wismar1 #aggd ,s ,another ,edition4 ,wismar1 #aghd ,r ,thollard de ,tarbes4 ,moyena prservatifs de la ,foudre et de la ,grle4 ,r ,thoresby1 ,r4 ,an ,account of a ,young ,man slain with ,thunder and ,lightning1 ,dec4 #bb1 #afih4 #dto4 #b pp4 7,phil4 ,trans4 xxi4 for #afii1 p4 #ea47 ,london1 #agjj ,r ,tieenk1 ,j4 ,bericht wegens de miswyzing van het compas1 door den donders4 7,verhandel4 van het ,genootschte ,vlissinqen41 iii4 #fae47 ,r ,tietz1 ,j4 ,die ,erfindung und erste ,verbreitung d4 ,blitzableiters4 #dto4 #ag pp4 7,jahrsbericht ber das ,kn4 ,kath4 ,braunsberg1 ,gymnasium zu ,braunsberg1 #ahej-ei47 #ahei ,r ,tilas1 ,d4 ,von einem ,donnerschlage in ,oesterwahla4 ,kirchspiele und ,waszmannlands ,hauptmannschaft1 im4 ,j4 #agdj4 #hvo4 #f pp4 7,k4 ,schwed4 ,akad4 ,abh4 iv4 #dc47 ,hamburg1 #agdb ,r ,tilesius von ,tilenau1 ,w4 ,g4 ,die ,wirkung des ,blitzes auf den menschlichen ,krper durch einen merkwrdigen ,fall erlutert4 #hvo4 #ac pp4 #a plate4 7,journ4 f4 ,chem4 ,n4,r4 ix4 #abi47 ,a ,toaldo1 ,g4 ,della ,maniera di defendere gli ,edifizii dal ,fulmine4 #hvo4 ,firenze1 #aggj ,r ,dell' uso dei ,conduttori metallici4444 ,apologia colla ,descrizione del ,conduttore 444 di ,padova4 #dto4 #cb pp4 #a plate4 ,venezia1 #aggd ,r ,del ,conduttore elettrico posto nel ,campanile di ,s4 ,marco in ,venezia 444 7#ast ed47 #dto4 #cg pp4 #a plate4 ,venezia1 #aggf ,r ,relazione del fulmine caduto nel ,conduttore della ,specola di ,padova4 7#ast ed47 #dto4 ,padova1 #aggg ,r ,a ,dei ,conduttori per preservare gli edifizj 444 ,memorie1 in questa nuova ed4 ritoccate ed accresciute di un' ,appendice 444 #dto4 #ajd pp4 #b plates4 ,venezia1 #aggh ,note4--,this work contains his 8,informazione al popolo0 of #aggb1 including his translation of ,saussure's 8,manifesto40 ,his 8,dell4 uso dei ,conduttori 444 ,apologia 444 of #aggd1 colla ,descriz4 del ,cond4 di ,padova40 ,his 8,del ,condutt4444 di ,s4 ,marco10 c4 of #aggf4 ,his 8,relazione del ,fulmine caduto nel ,condutt4 della ,specola1 ,padova10 of #aggg4 ,his 8,notizia del ,fulmine 444 nella ,torre dell' universita1 ,padova40 ,his 8,appendice sui fatti 444 recenti10 #aggh2 new matter4 ,it also contains an ,italian translation of ,barbier's 8,considrations en gnral10 444 which is a memoir appended to ,barbier's ,french translation of this work of ,toaldo4 ,this ,italian translation is by a printer1 and not dated4 ,note4--,in his 8,giornale ,astro-,meteorologico10 for or of #aghd1 8,dei principali accidenti dell' anno #aghc40 ,the first division is headed 8,della ,nebbia1 e della ,influenza de' ,fulmini10 and in which he refers to much writing on these subjects by himself and others in the 8,giornale enciclopedico di ,vicenza40 ,r ,fenomeno singolare d'un ,fulmine descritto1 e proposto all' esame de' fisici4 #dto4 #d pp4 7,opus ,scelti1 vii4 #ce47 ,milano1 #aghd ,r ,appendice3 ,riflessioni sopra i colpi di ,fulmine 7alla ,memoria del ,marzari1 8,descrizione d'una tempesta di fulmini407 444 ,letta #h ,feb41 #aghg4 #dto4 7,vide ,marzari47 ,saggi dell' ,accad4 di ,padova1 iii4 #bab1 pt4 i4 ,padova1 #agid ,r 7or ,anonym47 and ,saussure4 ,della maniera di preservare gli edifizi dal ,fulmine3 ,informazione al popolo4 #dto4 #ai pp4 #ast edition4 ,venezia1 #aggb ,note4--,annexed is his translation of ,saussure's ,exposition under the title 8,manifesto ossia ,breve esposizione20 the paging being continued from #bj to #ch4 ,the date of ,saussure's work is ,geneva1 #agga4 7,see also ,barbier de ,tinan47 ,r ,a ,tomlinson1 ,c4 ,the ,thunder ,storm4 ,an ,s ,account of the ,properties of ,lightning1 and of ,atmospheric ,electricity in various parts of the ,world4 #hvo4 #cdh pp4 ,london1 #ahei ,s ,on ,lightning ,figures4 7,ed4 ,new ,phil4 ,edinburgh1 ,jour47 #hvo4 #ahfa ,s ,further ,remarks on ,lightning ,figures4 ,edinburgh1 7,ed4 ,new ,phil4 ,jour47 #hvo4 #ahfb ,c ,the ,thunder ,storm4 #abmo4 ,london1 #ahfd ,r ,tourdes1 ,g4 ,relation mdicale de l'accident occasionn par la foudre1 le #ac ,juillet1 #ahfi1 au pont du ,rhin1 prs de ,strasbourg4 #hvo4 #cb pp4 ,paris1 #ahfi ,a ,trechsel1 ,f4 ,bemerkungen ber ,blitzableiter und ,blitzschlge1 veranlasst durch einige ,ereignisse im ,sommer1 #ahai4 ,gilbert's ,ann41 lxiv4 #bbg4 #ahbj ,r ,unterberger1 ,l4 ,f4 von4 ,ntzl4 ,begriffe von d4 ,gewittermaterie1 nebst ,beobachtungen b4 die beste ,art1 ,blitzableiter anzulegen4 #hvo4 7,see next47 ,wien1 #ahaa ,r ,ntzliche ,anmerkungen von den ,wirkungen der ,electricitt und ,gewittermaterie4 #hvo4 ,wien1 #ahaa ,vaillant4 7,see ,official ,instructions1 ,france47 ,c ,vallemont ,l4 ,l4 de ,description de l'aimant qui s'est form a la pointe du ,clocher neuf de ,n4 ,dame de ,chartres4 #abmo4 #bae pp4 ,paris1 #afib ,r ,vassalli-,eandi1 ,a4 ,m4 ,conghietture sopra l'arte di tirare i ,fulmini appo gli ,antichi4 #hvo4 7,opuscoli ,scelti di ,milano in #dto4 tom4 xiv47 #agia8 ,r ,nota sopra un mezzo facile di preservare le case rustiche dal ,fulmine4 7,calend4 ,georg4 #ahad47 #ahaj ,r ,vauquelin1 ,c4 ,on ,stones supposed to have fallen from the ,clouds1 7and discussion thereon7 in the ,french ,national ,institut4 vo4 #b pp4 7,phil4 ,mag4 xv4 #ahg47 ,london1 #ahjc ,r ,memoir on the ,stones said to have fallen from the ,heavens4 ,read in the ,french ,national ,institute4 #hvo4 #h pp4 7,phil4 ,mag4 xv4 #cdf47 ,london1 #ahjc ,r ,vauquelin1 ,l4 ,n4 ,mmoire sur les pierres dites tombes du ciel4 #hvo4 7,journ4 des ,mines1 xiii4 #ahjb-c47 ,paris1 #ahjb-c ,a ,verrati1 ,j4 ,dissertatione de ,electricitati coelesti4 #hvo4 ,bologna1 #agee ,r ,viacinna1 ,c4 ,del fulmine e della sicura maniera di evitarne gli effetti4 ,dialoghi ,tre4 #hvo4 #aef pp4 ,milano1 #agff ,r ,vismara1 ,g4 ,dei fulmini che hanno colpito il torrazzo di ,cremona4 ,memoria4 #hvo4 #bd pp4 7,extr4 del fascicolo di ,feb4 #ahda1 degli ,ann4 di ,fisica1 c47 ,milano1 #ahda ,r ,volpicelli1 ,p4 ,sulla necessit di proteggere dal fulmine le masse metalliche1 stabilite nella cima degli edifici4 ,nota4 #dto4 #e pp4 7,atti dell' ,accad4 ,pontif4 dei ,nuovi ,lincei1 sess4 i4 del #c ,dicem4 #ahfe1 tom4 xix4 pp4 #bb-bf47 ,roma1 #ahfe ,c ,walder1 ,e4 ,ueber wirkungsweise und ,nrdlingen1 ,construction der ,blitzableiter4 #ahfc ,r ,s ,walker1 ,c4 ,v4 ,transac4 and ,proc4 of the ,london ,electrical ,soc4 ,edited by ,c4 ,v4 ,w4 #dto4 ,london1 #ahda ,r ,s ,the effects of a ,lightning-,flash on 7#hd7 the ,steeple of ,brixton ,church1 and observations on ,lightning ,conductors generally4 ,large #hvo4 #ah pp4 #a plate4 7,proceed4 ,lond4 ,elect4 ,soc47 ,london1 #ahdb ,r ,on the ,action of ,lightning ,conductors4 ,la4 #hvo4 #ae pp4 #a plate4 7,proceed4 ,london ,elect4 ,soc47 ,london1 #ahdb ,r,c ,memoir on the difference between ,s ,leyden ,discharges and ,lightning ,flashes1 7#hd7 c4 ,la4 #hvo4 #db pp4 7,proceed4 ,lon4 ,elect4 ,soc47 ,london1 #ahdb ,r ,s ,proc4 of the ,london ,electrical ,soc4 #hvo4 ,london1 #ahdc ,s,walker1 ,c4 ,v4 ,the ,electrical ,magazine4 ,london1 ,vols4 i4 ii4 #ahde-df ,s,waltsgott1 ,j4 ,f4 ,de ,fulgure1 ,tonitru ac ,fulmine4 #dto4 #agcd ,r ,s ,watson1 ,w4 ,experiments on ,electricity4 #hvo4 ,london1 #agdf ,r ,a ,weber1 ,f4 ,a4 ,abhandlung von ,gewittern u4 ,zurich und ,gewitterableitern4 #hvo4 ,leipzig1 #agib ,r ,a ,weber1 ,j4 ,die ,sicherung unserer ,gebude durch ,blitzstrahlableiter theoretisch und praktisch beleuchtet und bewahrt1 samt einer ,beurtheilung der ,ableiter aus ,stroh von ,lapostolle4 ,eine ,vorlesung4 #hvo4 #df ,landshut1 pp4 #ahbb 7#abg7 ,s,weber1 ,l4 ,berichte ueber ,blitzschlge in der ,provinz ,schleswig-,holstein4 #hvo4 #be pp4 #b plates4 #ahhj ,s ,berichte ueber ,blitschlge in der ,provinz ,schleswig-,holstein4 ,zweite ,folge4 #hvo4 #gj pp4 #b plates4 ,kiel1 #ahhj ,r ,a ,wenzel1 ,c4 ,a4 ,w4 ,adhandlung ber die ,blitzableiter aus d4 ,franz4 #hvo4 ,wesel1 #ahah ,r ,adhandlung ber die ,blitzableiter2 aus d4 ,franz1 frei bers4 f4 angeh4 ,berlin1 ,ingenieur-,officire4 #b ,abtheil4 #hvo4 #ahbc-d ,a ,wharton1 ,w4 ,l4 ,the effect of a ,lightning ,stroke4 #hvo4 ,london1 #ahda ,r ,wilcke1 ,j4 ,k4 ,die ,meynungen der ,naturforscher von den ,ursachen des ,donners4 #hvo4 #ai pp4 7,schwedische ,akad4 ,hamburg und ,abhandl4 an4 #agei1 pp4 #ha and #aee47 ,leipzig1 #agei ,s ,von den ,versuchen mit den eisernen ,strangen1 den ,donnerschlag abzuwenden1 und dem dabei beobachteten ,merkwrdigoten4 #agei ,r ,bemerkungen bey einem d4 #cj ,may in ,stockholm geschehenen ,donner-,schlage4 #hvo4 #aa pp4 #a plate4 7,schwedische ,akad4 ,abhandl4 an4 #aggj1 vol4 xxxii41 p4 #aae47 ,leipzig1 #aggj ,r ,c ,wilson1 ,b4 ,observations on ,lightning1 and ,a the method of securing ,buildings from its ,effects4 ,in a letter to ,sir ,charles ,frederick4 #dto4 #fh pp4 7,phil4 ,trans4 an4 #aggc1 p4 #di47 ,london1 #aggc ,r ,further ,observations on ,lightning4 #dto4 #bf pp4 ,london1 #aggd ,r ,new ,experiments and ,observations on the nature and use of ,conductors4 #dto4 7,phil4 ,trans41 pt4 i4 p4 #bde47 ,london1 #aggg ,r ,a ,an account of ,experiments made at the ,pantheon1 on the nature and use of ,conductors2 to which are added some new ,experiments with the ,leyden ,phial4 ,read at the meetings of the ,royal ,society4 #dto4 #ajj pp4 #d plates4 ,london1 #aggh ,a ,s ,wilson1 ,r4 ,boiler and ,factory ,chimneys1 7#aaj7 and on ,lightning ,conductors4 #hvo4 ,london1 #ahgg ,a ,winkler1 ,j4 ,h4 ,abhandlung von dem elektrischen ,ursprung des ,wetterleuchtens4 #agdf ,a ,de avertendi ,fulminis ,artificio secundum ,electricitatis doctrinam ,commentatio4 #dto4 ,lipsi1 #agec ,r ,wittiber4 ber atmosphr4 ,electricitt und ,gewitter1 insbesondere die ,gewitter der ,grafschaft4 #dto4 #bc pp4 ,glatz1 #ahfj ,a ,wolff4 ,versuche ber ,blitzableiter4 #ahja ,r ,woodcroft1 ,b4 ,patents for ,inventions4 ,abridgments of ,specifications relating to ,electricity and ,magnetism2 their ,generation and ,applications4 ,printed by ,order of the ,commissioners of ,patents4 #hvo4 #gfi pp4 ,london1 #ahei ,r ,patents for ,inventions4 ,abridgments of ,specifications relating to ,electricity and ,magnetism2 their ,generation and ,applications4 ,part ii4 ,a4,d4 #aheh-ahff4 ,printed by ,order of the ,commissioners of ,patents4 #hvo4 #hfc pp4 ,london1 #ahgj ,r ,s ,wucherer1 ,g4 ,f4 ,von ,anlegung d4 ,blitzableiter auf ,kirchen u4 anderen ,carlsruhe1 ,hochgebuden4 #hvo4 #ahci ,r ,a ,yelin1 ,j4 ,k4v4 ber d4 ,blitzableiter aus ,s ,messingstricken u4 b4 d4 am #cj ,ap4 #ahbb1 erfolgt4 merkwrd4 ,blitzschlag auf d4 ,kirchthurm zu ,rosstall4 #hvo4 ,mnchen1 #ahbc ,r ,a ber die ,blitzableiter aus ,messingdrahtstricken4 #b;e ,aufl4 #hvo4 ,mnchen1 #ahbd ,c ,s ,zenger1 ,prof4 ,symmetrische ,blitzableiter4 7#ajd7 #dto4 ,a ,ziegler4 ,blitzableiter von ,platina4 ,allgem4 ,handlungszeit4 v4 ,leuchs #age4 ,ann4 de l',indust4 nation4 et trang41 etc4 xviii4 #cbj4 #ahbd ,,appendix ,h4 ,,application ,,to ,,and ,,replies ,,from ,,the ,,local ,,honorary ,,secretaries ,,of ,,the ,,society ,,of ,,telegraph ,,engineers ,,and ,,certain ,,other ,,distinguished ,,foreign ,,authorities4 ,in accordance with a resolution passed by the delegates at the meeting on ,october #bg1 #ahgi1 the following circular was prepared by the ,secretary1 and issued to the gentlemen named in the appended table4 #cj1 ,,great ,,george ,,street1 ,,westminster1 ,s4,w4 ,october #cast1 #ahgi ,dear ,sir1--,at the invitation of the ,meteorological ,society1 delegates have been nominated by the following societies3--,royal ,institute of ,british ,architects1 ,society of ,telegraph ,engineers1 ,physical ,society1 ,meteorological ,society1 to consider the present modes of erecting lightning conductors1 and improvements therein4 ,at the last meeting ,i was instructed to ask you to have the kindness to furnish the conference with copies of such papers or reports as may be convenient1 and as are generally accepted as authoritative in your country4 ,yours very truly1 ,g4 ,j4 ,,symons4 ,,name4 ,,country4 ,,date ,,of ,,reply4 ,allen1 ,j4 ,argentine ,republic ,aparicio1 ,don ,jos ,spain ,aylmer1 ,j4 ,france ,burton1 ,c4 ,bolivia ,cantoni1 ,j4 ,italy ,collette1 ,j4 ,m4 ,netherlands ,nov4 #gth4 ,cracknell1 ,e4 ,c4 ,new ,south ,wales ,dakers1 ,j4 ,canada ,d',amico1 ,e4 ,italy ,nov4 #af1 ,dec4 #h4 ,delarge1 ,f4 ,belgium ,field1 ,s4 ,d4 ,w4 ,america ,jamieson1 ,a4 ,mediterranean ,karsten1 ,g4 ,schleswig-,holstein ,nov4 #ac4 ,madsen1 ,c4 ,l4 ,denmark ,nov4 #e1 ,dec4 #g4 ,melsens1 ,f4 ,belgium ,nov4 #f1 ,dec4 #d4 ,michel1 ,f4 ,france ,morris1 ,j4 ,japan ,myers1 ,gen4 ,united ,states ,dec4 #ac4 ,nielsen1 ,c4 ,norway ,dec4 #a4 ,preece1 ,j4 ,r4 ,persia ,siemens1 ,w4 ,germany ,teale1 ,f4 ,g4 ,india ,dec4 #ab4 ,todd1 ,c4 ,south ,australia ,ward1 ,g4 ,g4 ,united ,states ,dec4 #i4 ,the following are abstracts of the replies received3-- ,nov4 #eth1 ,copenhagen4--,mr4 ,c4 ,l4 ,madsen acknowledging receipt of letter and promising further reply4 ,nov4 #fth1 ,belgium4--,m4 ,melsens acknowledging receipt1 and promising full reply4 ,nov4 #gth1 ,la ,haye4--,mr4 ,j4 ,m4 ,collette acknowledging receipt of circular and stating that lightning conductors are not in common use in ,holland1 that there are no official and scarcely any other publications upon the subject4 ,those who have to erect conductors upon public buildings usually rely upon the rules adopted in countries where the use of lightning conductors is more general4 ,nov4 #acth1 ,kiel1 ,schleswig-,holstein4--,dr4 ,karsten forwarding copy of the latest edition of his work on lightning conductors 7,see ,abstracts of ,printed ,documents1 pages 7#aad7 and 7#aai747 ,nov4 #afth1 ,rome4--,sig4 ,e4 ,d',amico acknowledged receipt4 ,dec4 #ast1 ,christiana4--,m4 ,c4 ,nielsen acknowledging receipt1 and forwarding copy of paper by ,prof4 ,mohn on 8,lynildens ,farlighed i ,norgi40 7,see ,abstracts1 page 7#ajf7 which he states is the only paper on the subject printed in ,norway47 ,dec #dth1 ,belgium4--,letter from ,m4 ,melsens1 sending series of his works4 7,see ,appendix ,g42 ,catalogue and ,appendix ,f4 pages 7#acg7 to 7#ada747 ,dec4 #gth1 ,copenhagen4--,mr4 ,c4 ,l4 ,madsen writes3 8,in continuation of my letter of #eth ult1 ,i have great pleasure in forwarding a copy 7enclosed7 of #8,regulations for the ,arrangement and ,construction of ,lightning ,conductors for ,military and ,public ,buildings in ,denmark1 as adopted by the ,royal ,engineers1 #ahfi1' which ,i have translated from the ,danish original1 and obtained the permission to place at the disposal of the ,conference4 ,the rules laid down in this paper are generally accepted as authoritative in ,denmark1 and have been followed in the erection of ,lightning ,conductors on the new ,royal ,theatre in ,copenhagen4 8,i beg to add that in case a printed report is to be published by the ,conference1 ,i shall feel much obliged by having a few copies sent to me1 and that ,i shall have great pleasure in continuing to have my attention directed to the subject40 ,,regulations ,,for ,,the ,,arrangement ,,and ,,construction ,,of ,,lightning ,,conductors ,,for ,,military ,,and ,,public ,,buildings ,,in ,,denmark1 ,,as ,,adopted ,,by ,,the ,,royal ,,engineers1 #ahfi4 7,translated from ,danish47 ,to obtain a perfect system of lightning conductors it is necessary to observe3 #a4 ,that the lightning conductor must be more exposed to the stroke of lightning than the building itself4 #b4 ,that the lightning1 after having struck the conductor1 shall traverse the conducting wire to the earth more readily than through any other neighbouring object4 #c4 ,that the lightning conductor is not destroyed by the stroke of lightning4 ,a4 ,arrangement4 ,on the highest points of the building are placed iron rods1 of such a length and number that no part of the building lies farther from the perpendicular line through the point of the rod1 than twice the height of the point above the place of the rod4 ,the lower ends of the rods are connected to a metallic conductor1 top conductor1 which follows the upper line of the building4 ,from the top conductor1 or from the rods1 and at least from each three of these1 conducting wires are led down the roof and outer wall 7best on the weather-side71 and thence one foot under the earth1 until about ten feet from the building4 ,here the wires are connected to the earth plate in a well1 the bottom of which well must reach a couple of feet under the lowest standing of the ground water4 ,each well1 with its plate1 ought at the utmost to serve three conducting wires4 ,if necessary to employ more wells than one1 the plates of these are joined up through a special conductor1 the earth conductor1 one foot under the surface of the earth4 ,great care must be taken that the earth plate is properly placed in ground water1 that more or less communicates with the ocean--a condition which1 in our country1 will hardly present insurmountable difficulties4 ,illustration3 ,sketch of arrangements for ,public ,buildings in ,denmark ,figure #a shows a system of lightning conductors for a building #ajj feet long1 with gable roof4 ,,note #a4--;,if the roof is covered with metal1 the conductors ought in several places to be connected to it2 but1 on the other hand1 they must be kept1 electrically1 as distant from all other parts of the building as possible1 especially from the metallic parts of it4 ,,note #b4--;,if ground water is found at a considerable depth1 under a dry layer of sand1 a second plate1 besides the general earth plate1 ought to be placed just beneath the surface of the earth1 the latter being made temporarily conductive by rain4 ,,note #c4--;,as to powder magazines1 which of course must be constructed of bricks or wood1 the lightning conductors must not1 without inevitable necessity1 be placed on the building itself1 but1 retaining the above-mentioned dispositions in the main points 7the top conductor excepted71 they ought to be placed on masts1 about ten feet from the magazine4 ,figure #b shows a system of lightning conductor for a powder magazine1 a hundred feet in length1 with gable roof4 ,illustration3 ,end and ,side elevation4 ,illustration3 ,plan4 ,b4 ,construction4 ,the point ought to consist of a solid copper cylinder1 inch diameter1 #f inches high1 conically pointed1 the top angle being about #cj degrees1 and with gilt top4 ,at the lower end a nut is applied1 by which the point is screwed and afterwards soldered to the end of the rod4 ,most conveniently the rod is formed of round iron1 which1 like the rest of the conductor above earth1 if constructed of iron1 is painted over or galvanized4 ,under earth only galvanized iron is suitable4 ,the upper diameter of the rod is inch2 #ab feet farther down1 #a inch4 ,the length is properly varying between #aj and #af feet4 ,it is to be preferred to use a greater number of low rods rather than fewer high ones4 ,the conductor1 as also the top and earth conductors1 may consist of an iron bar1 of square inch section1 consequently #i_/af inch in the square side1 or inch in diameter4 ,only for very great lengths will it be necessary1 on account of the increased resistance of the conductor1 to use thicker bars4 ,in place of iron1 copper may be used1 the section of which need only to be square inch4 ,the conductors must be of as short a length1 and with as few bends as possible2 and the latter must be rounded at their angle points4 ,they ought not to be bolted or spiked to the building1 but1 in view of changes of form occasioned by temperature or other reasons1 they must rest in hooks1 or be kept up by cramps that are fastened in wood or brick1 far from the metallic parts of the building4 ,it is of the utmost necessity that the conductor be continuous in its whole extent1 from the point to the earth plate4 ,links of chains or cables are to be rejected4 ,for this reason the number of joints must be limited1 and a constant contact of the respective ends1 extending over one or two square inches1 procured by bolts or rivets and soldering4 ,the metal should be filed on the contact sides1 so as to clear it from oxide1 this being an insulator1 and the soldering made with tin4 ,the earth plate may consist of galvanized iron or copper4 ,it ought to have at least a surface of #aj square feet in water1 or #e square feet area1 if to serve one conductor2 for each conductor in addition #ej per cent4 must be added to the area4 ,to diminish the circumference of the well1 the plate may be given a cruciform transverse section2 if then1 for instance1 the plate reaches #b feet down into the water1 the wings need only have the length of #f inches4 ,the well is constructed in the usual manner by digging or boring4 ,in order to preserve the conductor from breaking1 as the plate might press deeper into the ground1 a beam is placed across the well's upper part on which the horizontal part of the conductor rests4 ,inspection of the lightning conductor must be effected once a year1 and1 besides1 when circumstances demand it1 for instance1 after a stroke of lightning4 ,the inspection must especially have the purpose3 #a4 ,to examine whether the metallic continuity remains perfect2 to verify this a galvanometer is inserted1 and a galvanic current led through the conductor2 and #b4 ,to examine whether the conductivity to ground water is in order4 ,the earth plate being placed in a well1 instead of being buried in the ground1 will greatly facilitate this examination4 ,dec4 #hth1 ,rome4--,sig4 ,d',amico sent a copy of a letter received from ,professor ,tacchini1 ,director of the ,central ,meteorological ,office1 in answer to the communication made to him of the circular dated ,october #cast4 ,the following translation has been kindly made by ,professor ,t4 ,hayter ,lewis3-- ,,meteorological ,,central ,,office1 ,,rome4 ,november #bgth1 #ahgi4 ,,lightning ,,rods ,,in ,,use ,,in ,,italy4 ,although ,i have not sufficient material for giving a complete answer to the request made in your letter1 as noted in the margin1 yet ,i think that the accompanying notice as to the system in use in ,rome for fixing lightning rods may be useful to the ,director ,general4 #a4 ,the conductor of the lightning rod is constructed of iron1 #ag millimetres 7c4 rds4 inch7 diameter4 ,the upper terminal or receiver is #de metres 7#ad feet #i inches7 high1 with a copper point #jej 7c4 #a foot #h inches71 gilt from #jbe 7c4 #aj inches71 fixed on a pilaster of masonry #b metres 7c4 #f feet #f inches7 high1 and #fj centimetres 7c4 #b feet7 wide4 ,each terminal is intended to protect a horizontal superficies of radius double its height4 #b4 ,in order to obtain a conductor as long as required1 pieces of #e metres 7c4 #ah feet7 are united by a holdfast of brass4 ,the fastening of the conductor to the walls and roofs is made by little pieces of marble of the annexed form1 connected with the fabric4 ,illustration3 ,attachment and ,earth ,terminal used in ,italy ,a--,wall or roof4 ,b--,little piece of marble4 ,c--,hole through which the conductor passes4 #c4 ,it is the custom to connect the conductor with masses of iron1 and other metals in the building to be protected1 avoiding the water pipes4 7,referring probably to ,terra ,cotta pipes4 ,t4 ,h4 ,lewis47 #d4 ,in addition to the upper terminal and chief receiver1 it is usual to fix secondary points according to the form of the building4 #e4 ,the discharger or lower terminal 7in contact with the earth7 is made of copper rod1 #ab millimetres 7c4 inch7 square1 at least #f metres 7c4 #bj feet7 long1 in #c strips with points of copper arranged in the manner shown-- ,illustration3 ,attachment and ,earth ,terminal used in ,italy ,d--,conductor4 ,e--,lower terminal or discharger with points of copper4 #f4 ,the discharger is introduced into a ditch or well excavated in moist ground1 vertically or horizontally1 according to the circumstances of the locality4 ,the diameter of the well should be #jhj metres 7c4 #b feet #h inches71 filled with carbon1 and covered with earth4 #g4 ,in an ordinary building we employ a discharger to each #c points4 #h4 ,in this manner were made all the lightning rods of ,p4 ,secchi1 by ,signor ,lerigi ,morea1 maker of them in ,rome4 #i4 ,in some cases ,p4 ,secchi has made use1 for the conductor1 of the thicker wire used for the ,telegraph4 #aj4 ,we may observe that1 in other ,italian cities1 the same rules are adopted for the construction of lightning rods1 as ,i myself have verified4 ,only1 in some localities1 in place of putting points of copper to the lower terminal the latter is terminated by a copper band4 ,p4 ,,tacchini1 ,the ,director4 ,dec4 #ith1 ,new ,york4--,mr4 ,g4 ,g4 ,ward acknowledges receipt1 states that the only papers of any value upon lightning conductors1 published in ,america and known to him are3--7,a7 a paper by ,prof4 ,henry2 7,b7 a treatise by ,prof4 ,phin2 7,c7 a pamphlet by ,david ,brooks2 7,d7 a practical treatise by ,h4 ,spang4 ,the writer furnished copies of ,nos4 ,b and ,d1 and all four will be found noticed in the ,abstracts of ,printed ,documents4 ,see pages 7#ii7 7#ajb7 7#aag7 and 7#aab47 ,dec4 #abth1 ,calcutta4--,mr4 ,f4 ,g4 ,teale acknowledging receipt of circular and forwarding copies of two papers accepted as authoritative in ,india1 viz3--7#a7 ,r4 ,s4 ,brough on ,protection of ,buildings from ,lightning1 and 7#b7 ,w4 ,p4 ,johnston on the ,lightning ,conductors at ,dum ,dum4 7,see ,abstracts1 pages 7#aag7 and 7#acb747 ,dec4 #acth1 ,washington1 ,u4,s4,a4--,lieut4 ,kilbourne acknowledges receipt on behalf of ,gen4 ,myers1 enclosing copy of paper by ,prof4 ,henry1 and stating that the works of ,spang and ,phin are considered authoritative4 ,,appendix ,i4 ,,general ,,correspondence4 ,,trinity ,,house1 ,,london1 ,e4,c41 #fth ,february1 #ahhj4 ,,sir1 ,i am directed by the board to transmit to you herewith1 for the information of the ,lightning ,rod ,conference1 copies of reports made by ,professor ,faraday to this ,corporation1 one respecting a remarkable stroke of lightning which occurred at the ,eddystone ,lighthouse in ,january1 #ahec1 and the other upon a similar accident experienced at the ,nash ,lights in ,august1 #aheb4 ,the case to which ,admiral ,sullivan directed the attention of the ,conference1 as stated in your letter of the #cjth ,october last1 was probably one of these two4 ,should you desire any further details in connection with this subject1 the ,corporation desire me to assure you of the pleasure with which they will afford any information at their command4 ,i am1 ,sir1 ,your obedient servant1 ,,robin ,,allen4 ,g4 ,j4 ,,symons1 ,esq4 ,we have been favoured with copies of three separate reports by ,professor ,faraday1 and think that it is better to give them in chronological order4 ,there is only one other point in the correspondence from the ,trinity ,house which it seems necessary to mention1 viz41 that the sections of the copper rods now used are as under4--,,ed4 ,illustration3 ,,main ,,conductor4 #a in4 ,illustration3 ,,connecting ,,branches4 #a in4 ,,report ,,on ,,the ,,lightning ,,rods ,,of ,,lighthouses1 #ahdc4 ,,dungeness4--,dungeness ,lighthouse stands about #ad feet above the sea and measures #ig feet to the top of the lantern4 ,the tower is of brick with wood floors2 the roof and frame of the lantern are of metal seated upon a stone pedestal1 to which it is secured4 ,there is no conductor to the building4 ,the weathercock is fitted with a glass repeller1 and a rod similarly fitted is attached to the two copper flues which rise by the side of the lantern4 ,,eddystone4--,the height of the top of the lantern of the ,eddystone above the sea is about #ie feet4 ,the roof and framing of the lantern are of metal1 secured through a stone plinth to the gallery of the tower by metal fastenings4 ,a conductor of copper rod1 inch diameter1 is attached to the outside of the building2 the rod rises #c feet above the top of the lantern and terminates in the sea at low water2 it is fixed to the tower and lantern by metal stays and fastenings and is isolated by glass ferules4 ,to give stability to the building eight wrought iron ties are fixed in the interior of the house1 extending downwards from the underside of the lantern floor through the next two stories1 terminating by inserting the ends into the stone floor1 the upper ends are riveted into an iron ring round the manhole in the ceiling and further secured by iron bolts passing through the stonework and communicating indirectly with the metal work of the lantern4 ,illustration3 ,eddystone4 ,illustration3 ,spurn ,point ,high ,light4 ,,spurn ,,point ,,high ,,light4--,the ,spurn ,high ,light stands about #af feet above the level of the sea1 and measures #ajj feet to the top of the lantern4 ,the tower is of brick with wood floors2 the roof and framing of the lantern are of metal1 seated upon a stone plinth to which it is secured2 the weathercock is surmounted by a glass repeller4 ,an isolated conductor of copper rod1 inch diameter1 is attached to the outside of the tower rising some feet above the lantern and passing down the side of the tower below the surface of the ground4 ,,south ,,foreland4--,the ,south ,foreland ,high ,light stands above #cjj feet above the sea1 and measures from the ground to the top of the lantern #fg feet4 ,the tower is of brick1 the lantern roof and framing are of metal with a cast iron pedestal2 the weathercock is fitted with a glass repeller4 ,a conductor of copper rod1 inch diameter1 is attached to the outside of the tower1 of the same height as the weathercock4 ,the rod is fastened to the lantern and tower with metal stays and fastenings1 and passes into the ground1 turning off at right angles to the tower a little below the surface4 ,a copper flue connected with a stove in the base of the tower1 passes up the centre of the tower through the roof of the lantern1 to the lower end of which a copper rod has been attached1 which is carried to the outside of the building into the ground4 ,illustration3 ,south ,foreland ,high ,light4 ,the undersigned have1 according to their instructions1 met and considered the circumstances under which lighthouses are placed as respects lightning1 and have arrived at the following conclusions3-- ,that lighthouses should be well defended from the top to the bottom4 ,that as respects the top1 the metal of the lantern1 and upwards1 is sufficient to meet every need1 and satisfy every desire and fear4 ,that for the rest of the course down the tower1 a copper rod of an inch in diameter is quite1 and more than1 sufficient4 ,that at the bottom1 where the rod enters the earth1 it is desirable at its termination to connect it metallically with a sheet of copper #c or #d feet long by #b feet or more wide2 the latter to be buried in the earth1 so as to give extensive contact with it4 ,that glass repellers are in every case useless4 ,that glass thimbles are not needed1 but do no harm4 ,that if the repeller be removed1 and the point on the vane be terminated as the lightning rods usually are1 and then the metal of the lantern be strongly attached to1 and connected with1 the upper end of the copper rod1 and the rod continued down the tower to the earth1 and the sheet of copper buried in it1 such a system will be an effectual and perfectly safe lightning conductor4 ,that then there need be no rod end rising by the side of1 and above the lantern4 ,that the rod may 7if required on other accounts7 come down on the inside of the building1 or in a groove in the wall2 but should not be unnecessarily removed from observation and inspection4 ,that all large metallic arrangements in the stonework1 or other non-metallic parts of the tower of the lighthouse1 such as tying bars1 metal flues1 c41 should be well connected1 by copper1 with the conductor4 ,that the vicinity of two metallic masses without contact1 or metallic communication1 is to be avoided4 ,that1 as to the ,south ,foreland ,high ,light1 the lantern1 the central stove1 and the copper rod proceeding from it to the earth1 connected as they now are1 form a perfect lightning conductor1 even without the rod that is there erected2 but ,that it is important casual arrangements should never be depended upon for lightning conductors2 but a copper rod be established for the especial purpose3 for1 if the former be trusted to1 the carelessness or ignorance of workmen may1 at after periods1 upon occasions of repair or cleansing1 cause the necessary metallic connection to be left imperfect or incomplete1 and then the arrangement is not merely useless but dangerous4 ,that1 as to the ,eddystone1 it is desirable to connect the system of wrought iron ties in it with the lightning conductor1 by joining the lower part of that iron rod which is nearest to the conductor with the latter1 by a copper rod or strap1 equivalent to the conductor in sectional area4 ,that the ,dungeness ,lighthouse is in a very anomalous condition2 to rectify which the two repellers should be removed1 and also the representative of the top of a lightning rod attached to the flue1 and that then a good copper conductor should be attached to the metal of the lantern1 upon the principles already expressed4 7,signed47 ,m4 ,,faraday4 #beth ,september1 #ahdc4 99 99 99 99 99 #bc1 ,,gt4 ,,george ,,street1 #beth ,september1 #ahdc4 ,,sir1 ,the reference1 on the important subject of lightning conductors1 is to ,mr4 ,faraday and to me4 ,on receiving it ,i prepared drawings of the buildings to which our immediate attention was required1 with an explanation of their present conductors4 ,these were considered at a meeting with ,mr4 ,faraday1 when he explained the principles and their application to the several cases1 deduced from his copious experiments and scientific observations4 ,i have since received from him the accompanying ,report for my signature along with his1 but the report is altogether ,mr4 ,faraday's and therefore ,i prefer adding my approval of all it contains in this separate sheet1 and recommending that authority be given to me to act upon it4 ,i am1 ,sir1 c4 7,signed7 ,j4 ,,walker4 ,,jacob ,,herbert1 ,esq4 ,trinity ,house4 99 99 99 99 99 ,,royal ,,institution1 #bgth ,september1 #aheb4 ,,my ,,dear ,,sir1 ,i fortunately reached the ,nash ,low ,lighthouse last ,thursday1 before any repairs were made of the injury caused by the discharge of lightning there1 and found everything as it had been left3 the repairs were to be commenced on the morrow4 ,the night of ,monday1 #cjth ,august1 was exceedingly stormy1 with thunder and lightning2 the discharge upon the lighthouse was at six o'clock in the morning of the #cast1 just after the keeper had gone to bed4 ,at the same time1 or at least in the same storm1 the flag-staff between the upper and lower lights was struck1 and some corn stacks were struck and fired in the neighbourhood4 ,it is manifest that the discharge upon the tower was exceedingly powerful1 but the lightning conductor has done duty well--has1 ,i have no doubt1 saved the building2 and the injury is comparatively slight1 and is referable almost entirely to circumstances which are guarded against in the report made by myself and ,mr4 ,walker #bbnd ,september1 #ahdc4 ,the conductor is made fast to the metal of the lantern1 descends on the inside of the tower to the level of the ground1 and passes through the wall and under the flag pavement which surrounds the tower4 ,it is undisturbed everywhere1 but there are signs of oxidation on the metal and the wall at a place where two lengths of copper are rivetted together1 which show how great an amount of electricity it has carried4 ,a water-butt stands in the gallery outside the lantern4 ,a small copper pipe1 #a inch in diameter1 brings the water from the roof of the lantern into this butt2 it does not reach it1 but terminates #aj or #ab inches above it4 ,a similar copper pipe conducts the surplus water from the butt to the ground1 but it is not connected metallically with the other pipe1 or with the metal of the conductor1 or the lantern4 ,hence a part of the lightning which has fallen upon the lantern has passed as a flash1 or1 as we express it1 by disruptive discharge from the outside of the lantern to this tub of water1 throwing off a portion of the cement at the place1 and has used this pipe as a lightning conductor in the rest of its course to the ground4 ,the pipe has holes made in it in three places1 but these are at the three joints1 where1 it being in different lengths1 it is put together with tow and white lead1 and where of course the metallic contact is again absent2 and thus the injury there 7which is very small7 is accounted for4 ,the pipe ends below at the level of the ground in a small drain1 and at this end a disruptive discharge has 7naturally7 occurred1 which has blown up a little of the cement that covered the place4 ,some earth is thrown up at the outer edge of the pavement round the tower over the same small drain1 which tends to show how intense the discharge must have been over the whole of the place4 ,inside of the lantern there are traces of the lightning1 occurring at places where pieces of metal came near together but did not touch1 thus at the platform where a covering copper plate came near to the top of the stair railing1 but the effects are very slight4 ,all the lamps1 ventilating tubes1 c41 remained perfectly undisturbed1 and there was no trace of injury or effect where the conductor and the lantern were united4 ,inside of the tower and the rooms through which the conductor passes there were and are no signs of anything 7except at the rivetting above mentioned7 until we reach the kitchen or living-room which is on a level with the ground1 and here the chair was broken and the carpet and oil-cloth fired and torn4 ,to understand this1 it must be known that the separation between this room and the oil-cellar beneath is made by masonry consisting of large stones1 the vertical joints of which are leaded throughout1 so that the lead appears as a network upon the surface1 both of the kitchen floor above1 and the roof of the oil cellar beneath1 varying in thickness in different places up to or more of an inch1 as in a piece that was thrown out4 ,the nearest part of this lead to the conductor is about #i inches or a little more distant1 and it was here that the skirting was thrown off1 and the chair broken2 here also that the fender was upset and the little cupboard against the skirting emptied of its articles4 ,if this lead had been connected metallically with the conductor1 these effects would not have happened4 ,the electricity which in its tendency to pass to the earth took this course1 naturally appeared in the oil-cellar beneath1 and though the greater portion of it was dissipated through the building itself1 yet a part appeared in its effects to have been directed by the oil cans1 for though they were not at all injured or disturbed1 the wash or colour in the wall above four or five of them was disturbed1 showing that slight disruptive connections or sparks had occurred there4 ,at the time of the shock1 rain was descending in floods1 and the side of the tower and the pavement was covered with a coat of water4 ,this being a good conductor of electricity has shown its effects in connection with the intense force of the discharge4 ,a part of the electricity leaving the conductor at the edge of the pavement and the tower1 broke up the cement there1 in its way to the water on the surface1 which for the time acted to it as the sheet of copper--which ,i conclude is at the end of the conductor--does1 i4e41 as a final discharge to the earth4 ,also on different parts of the external surface of the tower near the ground1 portions of cement1 the size of half a hand1 have been thrown off by the disruptive discharges from the body of the tower to this coat of water3 all testifying to the intensity of the shock4 ,i should state that the keeper says he was thrown out of bed by the shock4 ,however1 no trace of lightning appears in the bedroom1 still there are evidences that powerful discharges passing at a distance1 and on the other side of thick walls may affect bodies and living systems1 especially by spasmodic action1 and something of the kind may have occurred here4 ,it may be as well for me to state that the upper floors are leaded together like that of the kitchen4 ,the reason why they did not produce like effect is evident in that they from their position could not serve as conductors to the earth as the lower course could4 ,the keeper said he had told the coppersmith to make the necessary repairs in the pipe1 and ,i instructed him to connect the waste pipe and the upper pipe by a flat strap of copper plate4 ,i would recommend that the lead of the lower floor be connected metallically with the conductor to a plate of copper in the earth4 ,i could not see the end of the present conductor1 not being able by any tools at the lighthouse to raise the stonework1 but ,i left instructions with the keeper to have it done1 and report to me the state of matters4 ,i am1 c41 7,signed7 ,m4 ,,faraday4 ,,the ,,secretary1 ,trinity ,house4 ,,eddystone ,,light4--,,report of ,,professor ,,faraday on ,electrical ,phenomenon which occurred thereat on the #aath ,january1 #ahec4 ,,royal ,,institution1 #bdth ,january1 #ahec4 ,,my ,,dear ,,sir1 ,in reference to the remarkable stroke of lightning which occurred at the ,eddystone ,lighthouse1 at midday on #aath ,january of this year1 and made itself manifest by a partial flash discharge in the living rooms1 ,i have to call your attention to the drawing herewith returned1 and to the circumstances which appear 7from it7 to have accompanied and conduced to the discharge4 ,in the body of the stone work above the store-room exist eight rings of metal2 each going round the building1 and each being four inches square of solid iron and lead4 ,also1 latterly the bedroom and sitting-room have been lined with a framework of iron bars1 situated vertically1 and pinned by long bolts into the stonework4 ,the part of the tower above the floor of the living-room is1 therefore1 filled with a metallic system1 which1 with the metal lantern1 gives a very marked character to the upper half of the structure4 ,the recent metallic arrangements 7but not the rings7 are connected with the lightning rod2 and the copper part of this rod1 beginning at the floor of the living-room1 then proceeds downwards by the course which can be followed in the drawing1 and terminates on the outside of the rock between high and low water marks4 ,considering all these circumstances1 ,i was led to conclude that the conductor was in a very imperfect condition at the time of low water2 and ,i had little doubt that ,i should find that the discharge had taken place when it was in this state1 and very probably with a spring tide4 ,the day of the stroke was the #aath ,january--a new moon occurred on the #ith1 so that it was at a time of spring tide4 ,the occurrence took place at midday2 and1 according to the tide tables1 that was close upon the time of low water at ,devonport4 ,the end of the conductor would then be #f feet from the water1 if the latter were quiescent1 and ,i cannot doubt that this circumstance gave rise to that diverted discharge which became so manifest to the keepers4 ,mr4 ,burges1 with whom ,i have conversed about the matter1 thinks it probable that1 through the violence of the waves1 the conductor does not now descend so much as is represented in the drawing4 ,i think it essential that the lower end of the conductor be made more perfect in its action2 and ,i should prefer this being done on the outside of the tower and rock1 if the rod can be rendered permanent in such a situation4 ,if it be impossible to prolong and fix the lower end of the conductor where it now is1 so that it shall have large contact with the sea at low water1 then ,i would suggest1 whether or no1 on the more sloping part of the rock1 about midway between high and low water1 three or four holes could not be sunk to the depth of #c feet1 and about #c or #d feet apart1 and that copper rods being placed in these1 they should be connected together1 and the lightning rod continued to them4 ,if this cannot be done1 then it might be right to consider the propriety of the making a hole through the centre of the building and rock1 about #b or more inches in diameter1 and #cj feet deep1 and continuing the conductor to the bottom4 ,a conversation with ,mr4 ,burges regarding the present state of the ,bishop's ,rock ,lighthouse1 now in course of construction1 induces me also to suggest the propriety of making provision for the lightning conductor as the work proceeds4 ,it would be easy now to fix terminal rods of copper1 and to combine them upwards with the work4 ,considering the isolated and peculiarly exposed condition of a lighthouse on this site1 ,i would propose that there be two conducting rods from the lantern1 down the outside on opposite sides of the tower1 each terminating below in two or three prolongations1 entering as proposed into the rock1 or into fissures below low water mark1 so as to be well and permanently fixed4 ,i am1 c41 7,signed7 ,m4 ,,faraday4 ,,the ,,secretary1 ,trinity ,house4 ,the present ,eddystone ,lighthouse1 that is the stone one erected in #ageg-ei from ,smeaton's designs1 has a total height from low water level to the top of the vane of #ajg feet4 ,the annexed engraving shows two conductors1 the old and defective one passing down the left hand side and terminating half way between high and low water level1 and the proposed new one on the right terminating in holes in the rock4--,,ed4 ,illustration3 ,,eddystone4 99 99 99 99 99 ,the following letter would have been placed in ,appendix ,a4 along with the replies from ,british ,manufacturers of ,lightning ,conductors2 but it did not arrive until long after they had been printed off4--,,ed4 ,please find enclosed answer to your questions4 ,in addition to manufacturing rods1 we have been protecting buildings with these rods for thirty years4 ,we sell in this way at retail from five to six hundred thousand feet each year4 ,we also issue a guarantee of #ejj 7#ajj7 on each building that we protect1 which we hold ourselves ready to make good in case of failure4 ,now1 in this extensive business1 we have only had to pay one dollar damage done by lightning4 ,we regard this as a practical demonstration that our method of protecting buildings with iron rods is as near perfect as it can be4 ,there is more profit to be made out of the copper rod1 as it is made cheaply out of sheet copper1 and can be sold much higher than the iron rod4 ,but knowing that iron for all practical purposes is the best material for lightning rods1 we feel it to be our duty to do all we can to introduce it4 ,we would most respectfully ask the ,conference to investigate this question as to what kind of metal is best for rods for practical use1 iron or copper4 ,our own late ,professor ,joseph ,henry pronounced in favour of iron4 ,we have many facts in relation to buildings being struck by lightning which we could give at some future time if desired4 ,we have gathered up a large number of points that have been melted by lightning strokes4 ,they are melted down about inch4 ,they all look as if the same amount of heat had been applied to each1 showing very clearly that the quantity of electricity in lightning strokes is quite uniform4 ,we have never in any instance known of the rod being melted1 showing that the rod which we use is of sufficient size4 99 99 99 99 99 #a #b4 ,we make spiral twisted iron rods weighing #de lbs4 to the hundred feet #g oz4 per foot4 ,the rod is of the same sized material throughout its length1 except that a copper point1 plated with silver and tipped with platinum1 is screwed on the upper terminal4 #c4 ,no proportion is observed between the length and sectional area4 #d4 ,joints are made by means of copper nuts4 #e4 ,attached to building by means of zinc strips1 or a casting that fits closely to the rod1 which is screwed down4 #f4 ,the rod extends from #i to #aj feet in the ground4 #g4 ,a circle twice the diameter of height of rod above roof4 #h4 ,all terminals on the roof are connected4 ,there are never less than two ground rods1 and these are increased as the number of upper terminals are increased4 ,we also manufacture copper rods1 but do not use them where we protect buildings1 nor do we recommend them to other dealers from the fact that our experience of thirty years has demonstrated that iron is the best material for lightning rods4 ,,cole ,,brothers4 ,,mount ,,pleasant1 ,,iowa1 ,,united ,,states4 99 99 99 99 99 ,a colliery chimney near ,sunderland1 #ahj feet high1 was struck by ,lightning1 ,november #acth1 #ahgh1 and ,i was sent for to repair it4 ,upon getting to the top1 which was about #ae feet diameter1 ,i found a great many of the bricks displaced1 and the upper terminal of the conductor 7which was a tube #jej in4 internal1 and about #jfb in4 external diameter1 and which had stood about #a foot above the top of the chimney7 had been fused and was lying on the top of the chimney1 it was quite brittle1 and easily broken by the hand4 ,the upper #aj feet of inch wire rope was in a similar state2 it seemed as if it had been passed through an exceedingly hot furnace1 and ,i rubbed it to dust in my hands4 ,this #aj feet length was above the first holdfast1 below the holdfast the wire rope was perfectly good4 ,the holdfast was one of those which are driven into a wooden plug let into the wall and pinned tightly down on the rope1 which had been badly bruised in the fixing--in fact1 knocked almost flat4 ,i believe that this was the cause of the accident1 and that the lightning travelled down as far as this holdfast1 and there meeting obstruction1 returned destroying the wire and rod and shattering the brickwork4 ,the earth connection was good1 the end was buried in a trench #b feet deep and #ae feet long4 ,t4 ,,massingham4 ,,newcastle-,,on-,,tyne4 99 99 99 99 99 ,i have been in communication with several of the principal brick builders here by whom the great majority of the chimney stalks in ,glasgow and the west of ,scotland are erected1 and ,i believe the following statements may be taken as correct3-- 7#a7 ,very few stalks under ninety feet in height have lightning conductors1 but1 as a rule1 the higher stalks have conductors4 ,one of my correspondents says that 8this rule holds good in four cases out of five40 7#b7 ,a chimney being struck by lightning is an extremely rare occurrence in this district4 ,one builder of long experience 7,mr4 ,mc,donald7 says1 8,i have known of several stalks that were struck by lightning1 that had no conductors4 ,i cannot point to one that was struck by lightning and had a conductor40 ,another firm of old standing 7,allan and ,mann7 say--8,in our experience we have not known of a chimney stalk1 with lightning conductor fixed1 damaged by lightning40 ,another firm 7,bell1 ,hornsby and ,co47 say--8,in our experience we have not known an ordinary stalk with or without a conductor struck by lightning10 and ,mr4 ,goldie says--8,during the last twenty years ,i can remember only one such case10 and he is not sure whether the stalk had a conductor or not4 ,there are three cases known to have occurred in ,glasgow1 but ,i never heard of any others among the hundreds--,i may say thousands--of chimneys which are here4 ,the great stalk at ,st4 ,rollox was struck shortly after its erection4 ,a stalk at the works of ,messrs4 ,alexander ,paul and ,co41 was struck about nine years ago4 ,mr4 ,goldie makes the remark--and ,i think it is well worthy of notice--that in all these cases the accident happened shortly after the completion of the stalk4 ,in these circumstances the stalk would still1 no doubt1 contain a large amount of moisture4 ,i think the ,st4 ,rollox stalk had a conductor fixed before it was struck1 but ,i am not aware whether either of the others had4 ,mr4 ,higginbotham 7,todd and ,higginbotham7 tells me that the stalk at their works was struck before it was quite completed4 ,it was very slightly injured4 ,it was afterwards struck as mentioned in my letter4 ,on that occasion it had a lightning conductor4 ,the damage done was not very serious1 but necessitated the binding of the stalk with numerous iron hoops--as thus strengthened it still stands4 ,mr4 ,higginbotham says that the opinion at the time was that the conductor saved the stalk from complete destruction1 but that it was too small4 ,they1 therefore1 had it replaced by a much heavier one--copper rope th of an inch diameter1 kept #a inches from the brickwork by glass insulators--which still remains4 ,j4 ,,honeyman4 #adj1 ,,bath ,,street1 ,,glasgow4 99 99 99 99 99 ,there was no lightning conductor of any kind at ,wells ,church4 ,the electric fluid struck the east side of the ,tower just above the ridge of the nave roof4 ,the tower stands1 or stood1 at the west end4 ,i enclose an account of the fire from a local paper3-- ,,wells4--,,total ,,destruction ,,of ,,the ,,church4--8,near midnight of ,saturday last1 ,august #bnd1 #ahgi1 a terrific thunderstorm burst over this town and a large district around1 causing most intense alarm and unfortunately ending in sad disaster4 ,the storm raged throughout the night1 and was accompanied in many places by a perfect deluge of rain4 ,between three and four a4m4 of ,sunday1 the #crd1 it appeared to reach its height1 the lightning being of a most vivid and alarming nature1 and the thunder reverberating in continuous peals4 ,a lull then occurred1 but between five and six a4m4 the storm again burst out with great fury1 and at #e4ej the electric fluid struck the church on the eastern face of the tower immediately above the apex of the roof1 driving out a large portion of the stone work1 the flints flying hundreds of feet around4 ,one large stone fell upon the roof of a house1 near the east window1 and penetrated to the room below1 which was fortunately unoccupied2 but the tenant1 ,mr4 ,r4 ,wharf1 who slept in the next room1 was aroused1 and one or two persons in the road seeing what had occurred1 and observing smoke directly after issuing from the roof of the church1 raised an alarm of fire1 which quickly awakened the whole town4 ,r4 ,m4 ,,phipson4 ,,norwich4 99 99 99 99 99 ,the first visible injury to ,wells ,church was the 8skinning0 of a portion of the tower 7about #aj feet high by #e feet broad7 extending downwards from the east window of the tower 7i4e41 the window which looked over the roof of the nave17 to the point at which the lead-covered nave joined the tower4 ,the lightning is believed to have set fire to the roof at this point1 and also to have travelled along the lead roof to the chancel1 and in crossing the vestry to have ignited the surplices1 as the church was seen to be on fire at both ends before the middle was touched4 ,the 8skinning0 was accompanied by great disruptive force1 as the stones from the tower were not only shot the full length of the church1 but one large one fell on the roof of a house #fj feet beyond the east end of the church4 ,,wells1 ,,norfolk4 ,f4 ,,long4 99 99 99 99 99 ,as your questions in the ,times of to-day allude only to protection to buildings from lightning1 ,i need not say anything on the perfect protection afforded to ,her ,majesty's ships by the conductors of ,sir ,snow ,harris1 from the time they were used in every ship in the service4 ,h4,m4,s4 8,beagle10 ,commander ,fitz,roy1 was one of the first ships fitted with them4 ,at ,monte ,video a heavy shock of lightning passed down the mainmast and through the ship without doing the slightest injury2 but as the vane staff which tapered to a fine point1 was fused at the point1 it enables me to answer one of your questions4 ,the copper was melted till the diameter was about one eighth of an inch1 but below that point the conductor was not injured in any way4 ,you will like to know a case in which a copper wire acted as a perfect conductor1 though fused throughout its length4 ,it was at ,monte ,video1 in the house of the ,english ,consul1 a flag-staff was struck1 and conducted the lightning through a flat roof1 near the bell wire of a suite of rooms 7the wire ran in sight near the cornice7 through a hole in each dividing wall1 and then down to the bell in the basement2 the wire was melted into drops like shot1 which burnt a row of small holes in the carpet of each room4 ,a dark mark1 on the cornice above1 showed where the wire had been4 ,at the bell there was a slight explosion1 and some little damage1 but ,i do not recollect whether anything acted partially as a conductor from that point1 and so carried off that part of the charge4 ,this1 ,i think1 shows that even an ordinary bell wire will act as a conductor for a rather strong stroke of lightning1 as the large flag-staff was shattered4 ,i am anxious to call the attention of your conference to a point that it will be interesting to clear up4 ,that is1 whether a conductor should be a solid rod1 or in a shape to give the largest amount of surface in the section8 ,when ,i tell you that ,faraday and ,harris each told me that the other 8knew nothing about it10 because they differed entirely on this point1 ,i think you will see the importance of it4 ,i had at the time to approve of the conductors for lighthouses4 ,i will1 if you wish it1 give you more particulars on this point1 as ,i believe it has never yet been settled3 lighthouses having been fitted with ,faraday's1 and ships and public buildings with ,harris' conductors4 ,the one being a solid bolt1 the other a hollow tube or double thin plates4 ,if ,harris was right there is an unnecessary amount of copper in ,faraday's solid conductors2 if ,faraday is right1 there is an unnecessary outlay in putting a given amount of copper into the shape of a tube1 instead of using it as a solid rod4 ,b4 ,j4 ,,sulivan1 ,admiral4 ,p4,s4--,you should get from the ,trinity ,house particulars of a case in which1 with a good solid conductor1 the iron floor of a lighthouse1 aided by some lead in the wall1 diverted the lightning from the conductor1 and caused damage inside4 ,i think it was a ,portland lighthouse1 but it is so many years since that ,i may not be right4 ,,tregen1 ,,bournemouth4 99 99 99 99 99 ,three or four years since1 ,i was looking out of my office window in ,finsbury1 when a flash of lightning struck the tower of the church of ,st4 ,giles'1 ,cripplegate1 towards which my sight happened at the time to be directed4 ,as a portion only of the flag-staff1 placed at one corner of the tower1 was destroyed1 ,i obtained permission to ascend the tower and discover the reason4 ,i found a substantial copper rope conductor fixed in a somewhat careless fashion to the back of the tower1 and passing some distance into the earth4 ,this copper rope was about an inch in diameter1 and was carried upwards1 under and over several projections and cornices1 and across the roof of the tower to its centre--where it stood erect1 and evidently did its assigned work admirably4 ,clumsy and unsatisfactory as the fixing of this bent copper rope seemed to me to be1 it is quite certain that it was most efficient2 and had it not been for the flag-staff1 capped with lead1 which was carried up considerably higher than the copper rope1 no evidence whatever of the lightning's path would have been revealed4 ,as it was1 the discharge of lightning struck the leaden cap of the flag-staff1 and descended down the wet1 wooden pole1 until the summit of the copper-rope conductor in the centre of the tower was reached1 when the discharge flew across to the metallic earth conductor1 leaving the lower part of the flag-staff unhurt1 but shattering to splinters that portion which was higher than the summit of the copper rope4 ,,richard ,,herring4 #bg1 ,,st4 ,,mary',s ,,road1 ,,highbury4 99 99 99 99 99 ,a small public-house of mine 7the 8,wheatsheaf07 stands at ,trolley ,bottom1 in the parish of ,flamstead1 between ,st4 ,albans and ,dunstable4 ,on ,wednesday1 ,august #fth1 #ahgi1 about #b p4m41 during a storm1 not otherwise very severe1 my tenant was seated by the tap-room window 7,a on the plan7 his wife being seated opposite to him1 and having the window on her left1 whilst she held her child with her right hand2 there were at the same time in the room about five men besides4 ,a sharp flash of lightning occurred1 and the poor woman 7when the smoke cleared away7 was observed to have fallen backwards4 ,she gasped twice1 never spoke1 and died immediately1 and bore no further mark of injury1 ,i understand1 than a slight mark as of scorching on her neck1 below the left ear4 ,i fail to recollect whether her clothing was scorched or not1 the child's shoe and sock were both burnt1 but she1 herself1 was unharmed4 ,all present were sensible of an atmosphere heavily laden with sulphurous fumes2 but1 excepting as above1 were absolutely unhurt4 ,on visiting the house about a week afterwards1 with a view to its repair1 ,i found a small round hole as if made with a bullet in a pane of the window 7,a7 close to which the woman was sitting1 but could discover no further injury either to the other panes1 the window-frame1 the floor1 or anything in the room4 ,in the parlour1 ,b1 the window-frame was violently wrenched outwards two or three inches1 several of the panes were broken1 one sash-line being scorched1 as also the frame and linings in places1 especially in the neighbourhood of the sash-weights 7iron74 ,the wooden chimney-piece ,e1 was slightly moved from its position1 the various articles upon it were scattered1 and a bottle of ink which stood there1 was thrown with some violence to the ceiling4 ,the upper part of the chimney to that room1 ,g1 and a portion of the wall1 of which it was a part1 forming the gable end to the house were shattered1 and at ,h a stout post1 contiguous to the house wall1 and supporting the roof of a lean-to1 was split and wrenched from its position4 ,the windows and frames upstairs1 ,c ,d1 were in the same state as that at ,b4 ,the chimney1 ,k1 to the tap-room1 was quite uninjured1 and no harm was done to any part of the back of the house4 ,illustration3 ,,elevation4 ,,plan4 ,flamstead is about four miles from ,luton1 and six from ,st4 ,albans1 and stands on high land4 ,trolley ,bottom is a hamlet half-a-mile distant1 and is1 as its name implies1 low-lying4 ,my house is1 perhaps1 the lowest in position there4 ,it faces the ,north-,west4 ,i fear that my experiences will be found to have but little bearing upon the main point you have in view1 viz41 the comparative merits of different descriptions of ,lightning ,conductors4 ,i venture to think1 however1 that they are not altogether without interest as illustrating the effects of lightning in a by no means exposed situation4 ,i am writing only from memory what was told me at the time1 and should you desire further information on any points1 shall be happy to endeavour to obtain it for you4 ,it would interest me very much to know how it is to be accounted for that1 whilst in the room in which the poor woman was struck1 no further damage was done1 other parts of the house were1 comparatively speaking1 wrecked4 ,,john ,,edward ,,groome4 ,,king',s ,,langley4 99 99 99 99 99 ,i was in a house at ,cannes 7,france7 belonging to my late father on the occasion of its being struck by lightning about five or six years ago4 ,the storm in which it occurred was a very short one1 consisting of only four explosions1 every one of which took effect on some building in ,cannes4 ,the rain was falling in torrents1 and to this ,i consider we owed our safety as the shoots and stack-pipes being full of water acted as conductors4 ,the villa stood high1 but another building very much higher1 and on higher ground1 was within #ajj yards4 ,the lightning struck the metal cowl of a brick chimney1 which1 being an addition1 was led down outside the walls of the house4 ,in the explosion the front of the grate of the room to which this chimney belonged1 together with fire-irons1 c41 were all projected across the room 7a large one71 about #cj feet2 but no marks of lightning having entered the room were apparent4 ,in fact the lightning after blowing up this chimney1 together with much of the roof and wall of the house 7great portions of the solid masonry of which ,i found #ej and #fj yards off67 appears to have left the chimney and1 taking the course of the iron shoot round the house1 to have divided into three streams1 each of which ultimately found its way down a separate stack-pipe1 melting in its way all the soldering of the joints1 but otherwise leaving them uninjured4 ,one stream passed thus into a well1 the door of which 7locked the night before7 was burst open1 ,i presume by the sudden expansion of the air1 another stream of the electric fluid passed into an underground drain1 which it burst up1 hurling into the air the trees planted above it1 the third passing across a level asphalt roof1 which it melted in spite of the water lying on it1 descended into the earth harmlessly4 ,you will see by this that the amount of electric fluid must have been very great to require all these modes of dispersion1 and it suggests the question whether the diameter of the ordinary conductors would be sufficient to carry off so great a stream4 ,of course1 in this case1 there was no conductor1 and therefore no means of testing it4 ,h4 ,,radcliffe ,,dugmore4 ,,the ,,lodge1 ,,parkstone1 ,,dorset4 99 99 99 99 99 ,thank you very much for the ,pamphlet1 which ,i have read with great interest4 ,messrs4 ,w4 ,w4 7page #f7 state that conductors in masts 7like ,harris's7 are 8most objectionable40 ,the best answer to that is3 that while ships were struck in the ,navy1 and lives lost every year before they were introduced1 no ship fitted with them ever received the slightest damage2 and since all ships were ordered to be fitted--now about #cj to #ce years--,i have never heard of the slightest damage1 or the loss of one life--that fact upsets all theories on the subject6 ,then connections between the higher and lower masts1 and especially at right angles1 are objected to on the ground that at a bend the conductor may be fused2 such a thing was never heard of in the thousands of conductors that must have been fitted in the navy4 ,even if the movable plate were turned back the lightning following the longest conductor would leave one mast for the other1 as the conductor went right over the mastheads1 and the two conductors nearly touched each other4 ,at ,spring ,grove1 near ,isleworth1 the church had a high spire which was fitted with a conductor1 but the ,vicarage was struck and some damage done to it1 though1 ,i think1 much nearer to the tower than its height4 ,i believe many are contented with one or two conductors to a building that should have many more4 ,my small house here is about #gj feet long by #ch feet wide1 and ,i have seven conductors--one to each chimney4 ,if it is once decided beyond dispute1 that copper conducts in proportion to its volume2 then a rod1 or flat-plate1 of about the proportions of one to four or five1 for the purpose of fitting closer round projections1 would be the cheapest and simplest form2 but if it conducts in proportion to surface then of course a tube1 double plate1 or wire rope1 would give the greatest protection at a given cost4 ,i firmly believe in the surface theory of ,harris4 ,i had been with him often when he made experiments nearly fifty years since1 and witnessed a strip of tin foil of the thinnest kind1 and about inch wide1 protect a model mast of about six inches in diameter from electric shock1 that without it split the mast to pieces1 aided by a small hole through its centre filled with gunpowder4 ,and ,i always thought that the surface-conducting theory of ,harris was indisputable4 ,but about #bj years since1 having to approve a proposal of the ,trinity ,house for a new conductor of a ,lighthouse1 which1 like previous ones1 was an inch in diameter copper rod called 8,faraday's ,plan10 ,i thought ,i would go up to the ,royal ,institution and ask him why he did not use a copper tube instead1 giving much greater conducting power with less copper4 ,i did so1 and he asserted positively that the conducting power depended entirely on the volume of copper in the section of the conductor1 no matter whether it was in a bolt1 plates1 or tube2 and that if ,harris said differently1 8,he knows nothing whatever about it20 of course1 ,i approved the rod conductor4 ,but singularly enough1 though ,i had not seen ,harris for years1 he came to town a few days after1 and came to the ,board of ,trade to see me1 and bring me a piece of his large tube conductor1 with a connection1 that he was fitting to the ,houses of ,parliament4 ,when ,i told him what ,faraday's opinion was1 he answered1 8,then he knows nothing about it40 ,i was still inclined to believe in ,harris2 but a few years after1 a young ,indian ,r4,e4 ,officer--,lieut4-,col4 ,stewart--whose death not long after was a serious loss to the service1 was sent home to procure the electric cables for connecting different ,indian ports4 ,i was asked by the ,secretary of the ,indian ,office to give him all the help ,i could4 ,one day he came to me with a piece of the cable he proposed using4 ,inside the iron wires was a single stout copper wire about of an inch in diameter4 ,i asked him why he had not the central wire of several strands as usual1 as ,i believed it would greatly increase the conductive power4 ,he said that he had carried out a number of experiments on this point before deciding2 and that he was satisfied the conducting power depended on the amount of copper in the conductor1 and consequently a solid wire was better than one of the same size made up by twisting small wires together4 ,this of course shook my confidence in ,harris' theory2 but it is a point that can be easily decided by experiments on a larger scale2 and ,i hope your ,committee will be able to decide it finally4 ,messrs4 ,w4 ,w4 prefer to a conductor on the masts a wire rope carried down from the truck1 stopped to a back stay4 ,the following fact will show its danger3--,a ,french frigate1 some fifty years since1 had one so fitted as an experiment2 while striking ,t4,g4 masts the conductor formed a large bight as the mast was lowered2 a man standing on cap or cross-trees--,i forget which--formed a shorter conductor between two parts of the wire rope and was killed without any other damage being done4 ,b4 ,j4 ,,sulivan4 ,,bournemouth4 99 99 99 99 99 ,with reference to your recent letter in the 8,times10 ,i shall be glad if you will inform me whether there has come under the consideration of the ,conference the question of lightning conductors on board iron ships with iron masts2 for my part they would seem to be useless1 and that if the iron mast have sufficient metallic communication1 through the bottom1 with the outside of the ship either by means of the screw shaft or in some other way2 no additional conductor1 copper ribbon1 or strip1 down the masts and along the decks over the ship's side1 or copper tube down the shrouds and over the ship's side could be of the slightest benefit4 ,in some ships one or other of these arrangements has been adopted1 and in others both have been applied at same time4 ,c4 ,m4 ,l4 ,mc,h,a,r,d,y4 ,,fern ,,hill ,,cottage1 ,,windsor ,,forest4 99 99 99 99 99 ,i have observed your letter in 8,the ,architect0 of ,saturday last4 ,with reference to the subject on which it treats1 ,i chance to have noticed since my residence here 7a period of eight years7 what ,i suppose to be an unusual frequency of lightning striking objects immediately round this spot1 and the neighbourhood generally4 ,this inference is suggested by the fact that within the period mentioned lightning has fallen within fifty yards of the same spot three times--that this summer 7one of those occasions7 two other houses1 both 7say7 within #ejj yards in a direct line from this spot1 were also struck--and generally1 ,i believe1 more objects are struck in this neighbourhood than usually happens to be the case4 ,my idea may be a fallacy1 for ,i have no sort of statistics by which to test it2 but if you suppose it is not so1 and if such points come within the scope of your inquiry1 ,i should be glad to send you a map marked with the spots where1 and the dates when1 lightning has fallen in or near this town4 ,the only local peculiarities ,i notice are3 #a4 ,an unusual number of houses close to this have lightning conductors 7a mere coincidence1 and not placed there on any impression like my own74 #b4 ,we are at the bottom of a deep bay of parabolic plan which may influence the movements of electrical disturbance4 #c4 ,a soil of sand and gravel containing much oxide of iron4 ,a4 ,,baldry4 ,,athelney1 ,,bournemouth1 ,,hants4 ,mr4 ,baldry kindly supplied the map1 and we find that a half circle of half a mile radius struck from the cliff-edge half a mile west of ,bournemouth ,pier includes the churches of ,st4 ,peter1 with one conductor1 and ,holy ,trinity with three2 eight private houses with conductors1 of which four houses have one each1 and the other four have two1 five1 six and seven respectively1 and within this area six objects are known to have been struck--three in the year #ahgi1 two in #ahga1 and one in #ahgj4 ,we do not know of any ,english locality where there are so many houses with conductors2 but there are many more remarkable cases of repeated injury within small areas--e4g41 in one storm in ,june1 #ahgh1 there were at least eight separate buildings injured within a circle of half a mile radius struck from the ,metropolitan ,cattle ,market in the north of ,london4--,,ed4 99 99 99 99 99 ,it occurs to me that it is worth while for the delegates of the ,royal ,institute of ,british ,architects to raise the question1 and1 if possible settle1 whether or not the gas pipes which permeate many buildings might or might not be utilized as lightning conductors2 and whether any risk of gas explosion would be incurred thereby4 ,in my own practice there occurred the case of a lofty building1 with a domed roof1 and a sun-burner with a #a inch gas-pipe to supply it1 rising to the summit of the dome1 and a large iron cowl over the sun-burner4 ,the same circumstance occurs in most modern theatres4 ,if the cowl were struck by lightning there was perfect metallic connection thence to the street gas mains--and one of larger sectional and superficial area than an ordinary lightning conductor would give4 ,h4 ,d4 ,,davis4 #b1 ,,finsbury ,,circus1 ,,city1 ,e4,c4 99 99 99 99 99 ,lightning conductors have been a great hobby with me for many years1 and ,i have induced a great number of clergymen and others to fix them to their towers and houses4 ,during my time in the navy and merchant service ,i witnessed many fearful effects of lightning1 and for the last thirty years ,i have been striving to persuade my friends to secure their houses from these terrific visitations4 ,on the #bdth ,december1 #afii1 the upper half of the fine steeple of this town was hurled to the ground1 and a large portion of the church broken in4 ,pinnacles were then substituted for the upper portion of the steeple1 to which ,i have had an efficient conductor attached4 ,as far as ,i can gather from records1 and from the abortions so frequently substituted for the original pinnacles of towers1 ,i have come to the conclusion that nearly every tower in this country has been struck by lightning during the last #djj years1 when nearly all the towers were built4 ,many years since1 the ,illustrated ,news gave a sketch of a beautiful steeple 7in ,norfolk1 ,i believe7 destroyed by lightning4 ,it was stated that this was the second steeple which had met with so sad a fate4 ,after the destruction of the first1 a second steeple was built by subscription1 at a cost of #a1jjj1 and the scaffolding had been removed only ten days when1 during a terrific thunderstorm1 this second steeple was entirely destroyed6 ,i wrote immediately to the incumbent to ask about the conductor1 and his answer was that none had been fixed1 but that it was quite decided that an efficient one should be attached to the third steeple6 ,this would almost appear incredible1 and ,i regret that ,i did not dot down the name of the ,parish and other data1 but ,i think it was about #bj years since4 ,the conductors ,i recommend are simply copper rods of inch diameter1 attached to the highest chimney1 and brought to the ground two or three feet under the surface4 ,when buildings are longer than they are high1 ,i always advise a conductor at each end4 ,i generally place the conductor four or five feet above the chimney1 and bring it out from the base of the building4 ,where a steeple or pinnacle has a vane it is only necessary to fix the conductor to the base of the spindle4 ,sir ,w4 ,snow ,harris recommended much heavier copper conductors1 but their great expense has prevented their adoption4 ,the old conductors in men-of-war were composed of long copper links1 of which nine feet went to the lb41 and these were always efficient when in place4 ,now of inch copper rod there are only five feet to a lb41 so that ,i give a larger margin for security4 ,,james ,,liddell4 ,,bodmin4 99 99 99 99 99 ,i observed your notice that you required information in reference to lightning and lightning conductors4 ,a case was brought to my attention last year which occurred in ,middlesborough4 ,i enclose you particulars of the same extracted from my report1 together with a tracing shewing the elevation and plan of the chimney shaft which was struck with lightning4 ,,baldwin ,,latham4 #g1 ,,westminster ,,chambers1 ,,victoria ,,street1 ,s4,w4 ,illustration3 ,plan and ,elevation of washhouse of ,middlesboro' ,fever ,hospital ,a4 ,wooden cover over boiler4 ,b4 ,boiler4 ,c4 ,iron disinfecting apparatus4 ,d4 ,iron flue into chimney4 ,e4 ,conductor4 99 ,position of fracture4 ,extract from a ,letter from ,mr4 ,e4 ,d4 ,latham1 ,c4,e41 ,borough ,surveyor of ,middlesborough1 dated ,october #aath1 #ahgh1 with reference to the striking by lightning of the chimney in connection with the washhouse at the ,middlesborough ,fever ,hospital at ,linthorpe3-- 8,the chimney1 which is a brick one1 is about #ej feet high and #e feet square at the base and stands at the north end of the washhouse1 as shown on the accompanying sketch4 ,the conductor1 a th inch copper rope1 is fixed on the south side of the chimney with holdfasts1 no insulators1 and finishes in the usual manner1 about #b feet above the top4 ,the conductor is carried under the ground for a distance of about #i feet from the chimney1 and terminates at a depth of about #d feet in hard1 rather dry clay1 the end being wrapped about three times round a common brick buried in the ground4 ,at a distance of about #i feet above the ground at the same side as the conductor1 and only about one foot from it there is a fracture in the brickwork where the electric fluid appears to have penetrated the chimney and gone a short distance down the inside1 to the flue connected with the iron disinfecting apparatus1 which stands at the side of the clothes boiler1 as shown on the plan4 ,the stone work of the top of the boiler was broken and other damage done40 ,extract from the reply of ,mr4 ,baldwin ,latham1 ,c4,e41 to the above communication3-- 8,it is no uncommon thing for buildings provided with what are called lightning conductors to be damaged by lightning1 and the cause is due to the inadequacy of the conductor to carry the electric fluid1 which will leave the conductor for a better or a larger conductor4 ,wire ropes are found to be one of the worst forms1 the same amount of metal when applied in a solid rod or ribbon is far more efficient1 as it offers less resistance than the strands of a rope4 ,you say your conductor is perfect1 but by examination of the drawings it will be seen that the lightning descended the conductor to a certain point4 ,at this point the iron flue enters the shaft1 but some distance from the conductor2 the mass of metal located there was a better conductor than the rope1 so that in leaving the rope for the better conductor1 the electric fluid passed through the brickwork and caused the damage4 ,if the boiler and flues did not join in metallic communication1 damage would arise from the fluid passing from the flue to the boiler1 and if the boiler were not in metallic communication with the earth1 farther damage would arise when the fluid left the boiler for the earth4 ,it is well known that electricity of high tension will leave small conductors for large ones1 and the knowledge of this fact is made use of in protecting the telegraph system throughout the country4 ,many buildings and chimneys have been struck that have been fitted with so-called lightning conductors4 ,a perfect system of protection against lightning consists in linking together all the conductors about the buildings4 ,such was the system introduced by ,sir ,w4 ,snow ,harris and adopted by the ,government40 99 99 99 99 99 ,reply of ,dec4 #abth1 #ahgh1 acknowledging receipt of ,mr4 ,baldwin ,latham's ,letter4 8,i am directed by the ,town ,council to tender you their thanks for the trouble you have taken1 and the valuable information you have given with reference to the lightning conductor at the ,middlesborough ,fever ,hospital4 ,,george ,,bambridge4 ,town ,clerk4 ,,corporation ,,hall1 ,,middlesborough4 99 99 99 99 99 ,subsequent action4 ,at the suggestion of the ,engineers of the ,telegraphs in the district1 the earth portion of the rope has been imbedded in a mass of coke1 and a quantity of old iron has been placed at the bottom of it1 to counteract the influence of the boiler and disinfecting apparatus4 ,i beg to report an incident which occurred on board the barque 8,southern ,queen10 from ,pensacola1 while coming up ,channel on the morning of the #cjth of ,december1 #ahgi1 the ,eddystone ,lighthouse bearing about north1 dist4 #bj miles4 ,at #f a4m4 of the above date1 saw a terrific squall rising in the ,w4,n4,w4 point of the horizon1 with vivid ,lightning in it4 ,we immediately reduced sails down to lower topsails and foresail1 and about #g a4m4 the squall of wind and hailstones overtook us3 it blew furiously for about twenty minutes1 and in the height of the squall a thunderbolt broke on the ship1 shattering the main royal mast-head1 thence the ,lightning ran down the main royal stay to the fore topmast head1 and shattering that also4 ,thence it ran down the chain of the fore-topsail haulyard and shattered about a fathom of the chain in bits4 ,when the bolt struck the ship it made a report like a hundred ton gun fired off4 ,the concussion on the ship threw every man off his feet4 ,it filled the cabin with smoke1 and also the hold3 the smoke had a sulphury smell2 also all the compasses in the ship were so magnetized that they were flying right round4 ,and on arrival into the ,commercial ,docks we observed that a plank on each side of the ship1 in the wake of the main chains1 had been blown out by the ,lightning4 ,on the port side the oakum has been blown out of the seams1 and the edges of the planks shattered4 ,since the ship has lightened up out of the water1 we have discovered that the electric fluid has passed out by a copper bolt1 cut the copper sheathing in the shape of a star1 and turned it back4 ,any further particulars ,i will be most happy to supply if required4 ,d4 ,,morgan1 ,master1 8,southern ,queen40 #ag1 ,,lime ,,street1 ,,london4 ,two of the delegates visited the ship1 but with the exception of learning from the mate that he saw 8a ball of fire descend from the mizen and go over the port side0 they had not been able to obtain any additional particulars4 ,they obtained some fragments of the broken chain1 a much rusted iron one1 weighing however about two pounds per foot4--,,ed4 99 99 99 99 99 ,the patterns of lightning conductors obtained from ,messrs4 ,hart1 as requested1 are an improvement on the first 8,spratt's ,patent0 purchased by the above-named firm2 the original was a mixture of copper and zinc wire1 which1 when it was exposed to a wet and smoky atmosphere1 a galvanic action took place and soon destroyed it4 ,about two months ago ,i engaged ,messrs4 ,davis1 of ,derby and ,newgate ,street1 to test a rope of the above construction that had been fixed about ten years at ,no4 #a1 ,aberdeen ,terrace1 ,blackheath1 and ,i was present at the time1 and though we had a very powerful battery we could not get a current through any part of it1 as both the copper and zinc had decayed3 the copper wire is not stout enough to allow for corrosion in this climate4 ,st4 ,michael's ,church1 ,blackheath ,park1 with the needle spire1 as we call it--built just fifty years ago--had a inch iron rod2 and as it now runs through the new vestry just built ,i have advised the churchwardens to have it tested1 and they are going to have it done in the course of a week or so4 ,st4 ,alphege ,church1 ,greenwich1 has a ribbon of copper about #a inches wide by inch thick1 and that has been up many years1 and is as sound as when it was fixed1 for ,i examined it about two months ago4 ,i have advised the owner of ,no4 #a ,aberdeen ,terrace1 to have a ribbon of copper1 as ,i am certain that wire ropes are not to be depended on in this climate4 ,hoping these few remarks will not be deemed out of place1 ,,charles ,j4 ,,heryet4 #ie1 ,,blackheath ,,hill1 ,,greenwich1 ,s4,e4 99 99 99 99 99 ,i have the honor to forward notes of an accident from lightning1 which ,i lately witnessed1 having been informed that your ,committee desires such information4 ,the very rough sketch which ,i attach is1 ,i believe1 accurate2 but ,i was only allowed to look in at the door while a strong light was held within1 and to view the outside of the building4 ,a native draughtsman belonging to the office1 however1 was allowed to make some measurements1 which he communicated to me4 ,it seemed to me that the case was worthy of record1 because the building was so little injured4 ,,john ,,asted1 ,lieut4-,col4 ,r4,e4 ,,masulipatam1 ,,madras ,,presidency1 #agth ,may1 #ahgh4 ,may #hth1 #ahgh4--;,camped at ,pedda ,kondur1 a village on the west bank of the ,kistna river1 about #aj miles below ,bezoarah anicut4 ,all the morning there was a southerly wind blowing unsteadily2 by noon it fell calm1 and was very hot1 clouds gathering in the east4 ,soon after midday thunder was heard to the east1 and a storm was evidently approaching4 ,about #c p4m4 wind began to blow from the east1 and soon rose to a gale1 bringing thick clouds of dust1 and the thunder sounded very near4 ,it rained rather heavily1 which laid the dust1 and black clouds could then be seen over-head1 and nearly all round3 the thunder1 which was very loud1 sometimes sounding quite over-head4 ,by half-past four the rain had slackened1 but thunder was almost incessant1 and very loud4 ,just at this time a stream of lightning descended within #hj yards of the tent1 and was accompanied by a tremendous explosion4 ,the lightning struck a small pagoda near the village1 and some of the natives said that they observed smoke rise from the summit when the lightning descended4 ,the accompanying rough sketch will show what the building is like4 ,the main part of it is a square pyramid1 each side of the square1 outside measurement1 being about #ah feet2 height of apex above ground1 #cb feet4 ,built on to one side of the pyramid is an entrance chamber1 with flat roof1 about #aj feet square1 and the same in height4 ,the apex of the pyramid is surmounted by a metal 7probably copper7 finial1 about #a foot in height2 the ordinary attachment of such a finial to masonry is by means of a small stake built into the masonry1 on which the finial--which is cast hollow--is fixed1 and round which it is plastered with mortar4 ,illustration3 ,plan and ,elevation of ,indian ,pagoda ,the interior of the pyramid forms one room1 about #aj feet square1 with a domed ceiling1 the thickness of the dome at crown being #b feet4 ,in the centre of this room is placed the idol1 in this case a lingam1 or cylindrical stone pillar1 #a foot #d inches high1 and about #i inches in diameter1 which stands on a square hollow stone tray 7not cut out of one stone1 but fitted in two or more pieces7 in which the offerings of ghee1 c4 are placed4 ,this tray has a small spout on each face to carry off the liquid ghee and water with which the priests' ablutions are made4 ,the tray is raised on masonry1 so that the height of the top of the lingam is #c feet #d inches from the floor4 ,the floor of the room is #a foot above the surrounding ground2 there is only one doorway leading from the porch or entrance room above mentioned2 and the sacred edifice is closed by a substantial wooden door1 with iron hinges and lock1 on the outer face of the entrance chamber4 ,the whole building is of brick in mortar1 unplastered1 and presents the appearance of being weather worn4 ,the pagoda is at a distance of about #bj yards from some low native houses1 and stands in an open space1 on two sides of which is the native village2 round the houses are some trees1 mostly of small size1 but within #ej yards of the pagoda are two separate trees1 which certainly exceed it in height4 ,the village is situated on the margin of the ,kistna river1 and the surface of water in wells is at least #aj feet below the surface of the ground4 ,the lightning struck the metal finial on the top of the pagoda1 and passed vertically through the dome1 travelled along the east side of the lingam without leaving any mark1 and bored a small round hole in the stone tray beneath it1 passing into the ground below without disturbing the idol or its foundation4 ,the hole in the tray was not quite large enough to admit the point of a little finger1 and it was situated on a joint of the stone1 a place where moisture would probably linger4 ,the finial appeared undisturbed1 but the masonry immediately round its base was shattered1 and a shower of pieces of brick and mortar was sent from the top of the pyramid and scattered over the ground on the east side to a distance of about #bj feet from the base4 ,the masonry of the apex of the pyramid was cracked in three places1 and a small hole was bored in it1 on the east side of the finial1 apparently about the same size as that in the stone tray2 but otherwise the masonry of the building appeared totally uninjured--not a crack could be found anywhere4 ,the soil at this place is a clayey loam1 rather lighter than the ordinary delta alluvial soil4 ,when the building was struck a sulphurous smell was noticed4 ,,john ,,asted1 ,lieut4-,col4 ,r4,e4 ,,masulipatam1 #agth ,may1 #ahgh4 99 99 99 99 99 ,,irish ,,lights ,,office1 ,,dublin1 #acth ,march1 #ahhj4 ,,sir1 ,adverting to your letter of the #acth ultimo1 ,i have now the honour to forward herewith for the information of the ,lightning ,rod ,conference copies of two ,reports relating to the lighthouse at ,berehaven being struck by lightning1 in #ahgg1 which1 no doubt1 is the ,station alluded to by ,professor ,tyndall in his conversation with ,mr4 ,inglis1 of the ,trinity ,house4 ,i am1 ,sir1 ,your obedient ,servant1 ,w4 ,,lees1 ,secretary4 99 99 99 99 99 ,,irish ,,lights ,,office1 ,,dublin1 ,february1 #ahgg4 ,,sir1 ,i most respectfully beg leave to state that1 in accordance with your instructions ,i proceeded to ,berehaven ,lighthouse1 and on my arrival at that station ,i made a very careful examination and found that the lightning was conveyed into the lantern by the iron stay bars that were connected to the lightning conductor at a collar about #e feet over the gutter on the outside of the dome for the purpose of securing it1 and bolted to the dome of lantern by iron bolts4 ,after bursting off the several coats of paint at the heads of the bolts1 it put out the lights1 breaking the glasses1 and knocking down both light keepers insensible2 it having twisted off the lead voice-tube where it was secured to the side of the lightroom by a holdfast1 bursting out the stone sheeting between the iron pillars supporting the marble top2 it then passed through the voice tube to the principal keeper's bedroom1 where it burst out the studding and lath and plaster1 and tearing away the voice-tube1 the foot-board of the bed1 and destroying the pictures that were hanging on the walls4 ,it would appear that the current was interrupted in its course by the sudden bend of the voice-tube2 for1 after having dealt destruction in this apartment it was attracted by the iron holdfasts and spikes that secured the voice-tube and studding to the walls1 and passed out through the external walls of dwelling to the out offices1 where it passed along the eave gutters to the end of them2 it then followed one of the iron holdfasts1 and entered the wall1 destroying it1 and bursting out the cut-stone kneeler and barge course1 it then passed down through the roof of the low buildings1 destroying the slating1 passing through the walls of the pantry1 c41 tearing up portions of the #c inch ,yorkshire flagging of the floor and yard1 dealing destruction to the shelving1 doors1 door frames1 brickwork1 glass1 c41 and bursting up the seat of principal keeper's w4c41 it passed along the sewer to the assistant keeper's w4c41 breaking up the flags and seat and then passed out through the roof4 ,another current was attracted by the eave gutters at the east angle of the dwelling near the tower1 and passed along them to the north east angle1 splitting them through the centre4 ,at this point its course was changed to the west1 and passed into the assistant keeper's yard and down the rain water pipe to the water tank1 splintering it and the slating and brick wall1 c42 it also appears that the lightning struck the south-east side of the tower and entered it in several places at the base and near the lightning conductor1 and apparently glanced off it where it was secured by holdfasts to the tower1 rooting up the solid rock1 but giving no indication that it had been conveyed to earth by the conductor as intended3 the lightning also entered the assistant keeper's kitchen through the chimney1 knocking down a portion of the brickwork1 c4 ,i may remark that the lightning conductor is formed by a copper rod1 which stands about #aj feet over the gutter on the outside of the lantern1 and is secured by three iron stays to the dome1 as before described1 and passes down through the centre of the gutter to the under side1 where it is connected to a -inch copper-wire rope1 which continues down the outside of the lantern close to the glass to the floor of the balcony1 passing through the stone floor by means of a hole1 jumped through it1 then continues down the face of the tower closely pressed to it by the iron holdfasts and copper bands1 which secure it until it reaches the rock at the base of the tower1 where it terminates in a small hole #c inches by #c inches1 jumped out of the rock about #f inches under the surface4 ,after having made a careful survey of the damage done1 ,i deemed it advisable1 and at the solicitation of the principal keeper1 who seems to have been greatly shaken and nervous1 to have the iron stay-bars disconnected from the dome of the lantern and the bolt-holes plugged up with timber1 fearing a recurrence of the accident1 as the weather was very stormy1 and should lightning come on no person on the rock would enter the lantern4 ,i also considered it prudent to have the loose gutters and cut-stone1 also a part of the gable of the out offices1 taken down1 as it was in danger of falling into the narrow yard1 which might cause a sad accident4 ,having provided workmen and materials and scaffolding for doing this work ,i again landed on the rock on ,saturday last1 with great difficulty1 having been detained a day by the storm1 and pointed out the temporary repairs that were necessary to be done for the protection of the people on the rock4 ,the probable cost of repairing the damage done the buildings1 independent of the lightning conductor1 and which require to be done without delay1 will be #abj4 ,hoping the action ,i have taken in this matter will meet with your kind approval1 ,i have the honour to be ,your most obedient ,servant1 7,signed7 ,a4 ,j4 ,,bergim4 ,the other report is to the same effect as the above1 and is therefore omitted4--,ed4 99 99 99 99 99 ,,accident ,,by ,,lightning at ,upwood ,gorse1 ,caterham1 the residence of ,j4 ,,tomes1 ,esq41 ,f4,r4,s4 #bh ,may1 #ahgi4 ,as ,i happened to be visiting ,mr4 ,tomes1 in the autumn of #ahgi1 ,i took the opportunity of obtaining all the particulars ,i could with reference to the accident which occurred on the night of the #bhth ,may1 #ahgi1 when his house was struck by lightning4 ,the house1 a sketch plan and elevation of which are annexed1 stands upon a hill upwards of #gjj feet above sea level1 and is somewhat higher than any other object in the vicinity4 ,it is covered by a steep tiled roof1 that of the principal portion of the house being somewhat higher than the rest1 and upon the ridge of this roof stand two brick chimney stacks of equal height4 ,upon the eastern stack1 at its southern end1 was fixed a lightning conductor 7shown by the line1 ,a4 ,b4 ,c41 on the south elevation71 the upper part consisting of a point and a length of copper tube an inch external and inch internal diameter1 which was screwed into a collar connected to a woven band of one zinc and thirteen copper wires carried through glass insulating rings along the slope of the roof1 over the rain-water gutters and down the side of the house into the ground1 going only #ab inches into dry chalk4 ,the electric fluid struck the lightning conductor1 hurled the rod down and shattered the chimney pots and some of the brickwork4 ,the rod was broken at the point marked ,a on the south elevation1 where the sectional area of the copper rod was reduced by the screw being cut into it for the collar1 which connected the rod with the woven band4 ,this junction and a portion of the band are forwarded for inspection1 from which it will be seen there are no rough broken surfaces1 but that the thread of the screw was partly melted4 ,the copper wires composing the band were bright and nodulated here and there throughout their length1 showing that it had been heated up to a sweating temperature4 ,the zinc wire was not continuous1 having been wasted by oxidization4 ,it showed no indication of having been hot4 ,illustration3 ,,upwood ,,gorse1 ,,caterham4 ,scale--#a inch #cb feet4 ,having broken the conductor1 the discharge appears to have divided at the ridge of the roof1 a portion passing down the southern and a portion down the northern slope of the roof4 ,that portion which passed down the southern slope apparently followed the course of the conductor band as far as the iron rain-water gutter1 which it cracked1 and perforated two holes1 about half an inch diameter1 in two panes of glass at ,b4 ,here the current apparently again divided1 as shown by the dotted line from ,d to ,e on the south elevation1 some passing westwards and some eastwards along the rain-water gutter round the eaves of the house1 as traced by the broken joints of the gutter4 ,westwards these joints 7which were made of red lead7 were only broken from ,b to ,d1 but eastwards they were broken from ,b to ,e1 and right round the eastern side of the house to ,f1 and along the northern side as far as ,g4 ,what seemed to be the greater portion of the discharge1 however1 passed down the northern slope of the roof and along the course shown by the dotted lines on the ,plan and north elevation4 ,the lightning first followed the lead flashing ,h of the chimney stack1 next broke some tiles at ,i1 and then without disturbing any of the rest of the tiling1 leapt across the roof1 a distance of some #ae feet1 to two galvanised iron water cisterns in the roof at ,k1 perforating a hole through the #i-;inch brick wall of the house in its course4 ,this hole1 which was circular1 was large enough to admit one's finger easily and was blackened on its interior2 when first examined1 eight or ten minutes after the occurrence1 it was still quite hot4 ,one edge of the lead flashing outside the wall was fused at ,g1 close to the rain-water gutter1 from which it would seem that the current again divided at the wall of the house4 ,there are two galvanised iron cisterns at ,k1 connected by a pipe underneath 7see adjoining sketch plan71 and the discharge appears to have passed from one cistern to the other and then along the #a inch iron barrel rising main1 from pumps1 to the point ,l#a in the back kitchen1 where the iron pipe separated into two branches leading to the two pumps ,l#b and ,m4 ,probably a portion of the discharge passed down the iron suction pipe from the pump ,l#b into the rain-water tank ,p1 but however this may have been1 a considerable portion passed from point ,l#a along the #a inch iron pipe ,,lm to the pump ,m in the scullery1 and thence along a inch iron pipe to a water tap fixed over the iron sink ,n1 but not in metallic connection with it4 ,here the lightning broke the slate at the back of the sink and sent it showering across the scullery1 breaking the things on the opposite side of the room4 ,the iron sink was set on brick piers and connected1 by means of a #a inch iron pipe1 with the self-acting syphon 8,flush ,tank0 ,o in the yard4 ,this 8,flush ,tank0 consisted of a cylindrical cast-iron tank about #bf inches in diameter and #bf inches deep1 buried two-thirds in the ground1 so that it formed a fair earth connection4 ,there is an account of the accident in a letter by ,mr4 ,charles ,s4 ,tomes in ,nature1 of #ab ,june1 #ahgi 7which has been made use of in the present description71 and there is also a letter about the accident by ,mr4 ,newall on the next page of ,nature to ,mr4 ,tomes' letter4 ,the description in this latter letter is1 however1 erroneous in several particulars1 especially where it speaks of the lightning passing round the iron gutters to the iron water cisterns4 ,,rogers ,,field1 ,b4,a4 ,lond41 ,m4 ,inst4 ,c4 ,e41 ,f4,m4,s4 ,,cannon ,,row1 ,,westminster4 ,,note4--,mr4 ,tomes has most kindly sent the whole of the upper parts of the conductor2 and as the accident appears a very instructive one we give full details1 together with engravings of the more important portions of the conductor4--,,ed4 ,this conductor was of the pattern known as ,spratt's patent4 ,the upper terminal was what the vendors call a 8reproducing point10 which they say is 8formed of two or more metals3 the inner or core being steel1 and the outer of silver alloy1 tipped with platinum20 the idea of the inventor is said to have been that 8should the outer coating become fused by an extraordinary charge of electricity1 the core will remain intact to receive any further discharge40 ,in the present case the top is broken and the iron centre is rusted and bent1 but there is no indication on the remaining portion of heat or fusion4 ,this point ,a was well screwed into a stout copper collar ,b4 ,illustration3 ,d ,illustration3 ,f ,into the same collar was screwed the upper end of a copper tube ,c1 #e ft4 #a in4 long1 external diameter1 #je in41 and internal diameter about #jcf in41 giving a thickness of only #jjg in41 or but little more than a sixteenth of an inch4 ,the mass of copper was therefore about equal to a tape #a #a_/af1 or 1 or to a rod one-third of an inch in diameter--the area being as nearly as possible #jji in4 ,the tube weighs #bi ounces1 which corroborates the above measurements and shows that it weighs rather less than #f ounces per foot4 ,this part of the conductor was evidently greatly heated1 as there are distinct marks of sweating in several places4 ,the lower part of this tube was screwed into the collar ,d 7which is drawn of its actual size in the annexed sketch7 in order to make connection with the short length of copper tube ,f1 a portion of which is also engraved1 of its actual size4 ,it was at ,e that the rupture occurred4 ,the charge passed the point ,a1 then the top collar ,b1 and although it greatly heated the #e ft4 copper tube ,c1 still no damage was done1 and so it passed into the second collar4 ,here1 however1 there seem to have been two faults3 the short copper tube ,f1 was very slight1 weighing but little over #c ozs4 to the foot1 and this1 which represents but a very slight conductor1 was greatly lessened by a deeply-cut thread to the upper end1 whereby the area was reduced to less than #a_/bjth of an inch4 ,as this was not screwed home1 the total sectional area at ,e immediately below the collar was reduced to the above small amount1 rupture and fusion occurred1 and much of the charge left the conductor4 ,this short length of tube was1 however1 raised to a sweating temperature in two places4 ,illustration3 ,sections of ,rod at ,upwood ,gorse1 ,caterham ,the conductor consisted of #ad wires made into a flat plait1 the wires seem to have been of the following dimensions3-- ,each of ,no4 ,total area4 #ab copper wires1 #ae ,b4,w4,g41 dia4 of each #jgb in43 #jjdh in4 #a copper wire1 #ah ,b4,w4,g41 dia4 of each #jdi in43 #jjja in4 #a zinc wire1 of each #jdi in43 #jjja in4 ,thus the total sectional area of the plait ,g would be about #jjej in41 or rather more than that of the short copper tube into the lower end of which it was roughly thrust and riveted--but the joint was bad1 there was no solder at all1 and the metallic contact was very imperfect4 ,as to the state of this plait 7which was less than an inch wide1 and less than in4 thick71 and as to the ridiculously imperfect earth terminal1 details are given in ,mr4 ,field's letter4 ,it may be well to recapitulate the dimensions3-- ,,description4 ,,length4 ,,dimensions4 ,,sectional ,,heat ,,effects4 ,,area4 8,reproducing #i in4 #jde #jde #jbj ,none visible4 point0 in4 ,collar #a in4 #jge in4 #jbd ,none visible4 diam4 ,external #je in4 dia4 ,sweated in ,copper tube #e ft4 #a in4 ,internal #jji places4 #jcf in4 dia4 ,external #jge in4 dia4 ,collar #a in4 ,internal #jbd ,none visible4 #jej in4 dia4 ,external #jej in4 dia4 ,sweated in ,short tube #g in4 ,internal #jji places4 #jcge in4 dia4 ,external ,short tube #jdch in4 where in4 dia4 #jjd ,fused4 threaded ,internal #jcge in4 dia4 ,plait #ec ft4 8 #jg #jjgb #jje ,sweated in in4 places4 ,g4 ,j4 ,s4 99 99 99 99 99 ,we herewith hand you our circular1 setting forth our ideas as to lightning conductors4 ,we claim that if one or more sharp edges or points is so essential on the most elevated part or parts of a conductor1 why not establish this principle the entire length of the conductor8 or why not leave these most elevated part or parts blunt1 or erect a small gilt ball8 ,,david ,,munson ,co4 ,,indianapolis1 ,,indiana1 ,u4,s4,a4 ,illustration3 ,sections of ,munson's ,rods ,the engravings are not drawn to scale1 but are here reproduced2 the shaded parts are galvanized iron1 the lighter parts copper4--,,ed4 99 99 99 99 99 ,i think that it would be very valuable if the ,conference considered how far iron ventilating pipes to drains will safely act as lightning conductors4 ,these pipes generally consist of iron jointed with red lead or putty4 ,will not these joints interfere8 ,very often also a portion of the pipe is wholly of lead4 ,so many of these pipes are now carried up to a very high level that the question is important4 ,,rogers ,,field1 ,m4,inst4,c4,e4 ,,cannon ,,row1 ,s4,w4 99 99 99 99 99 ,our opinion is that the drain to our ,powder ,magazine at ,bruntcliffe 7see ante page #gd7 had no water in it at the time of the occurrence4 ,,john ,,haigh ,,sons4 ,,victoria ,,collieries1 ,,gildersome4 99 99 99 99 99 ,we have the pleasure to send you a plated model of our new ,conductor ,coupling1 and hope you will be pleased with it4 ,when screwed up1 the contact between the rod and the copper tape is perfect4 ,it is1 of course1 a very simple thing1 but it overcomes the difficulty of soldering1 which is always more or less uncertain1 and rivetting up aloft is apt to be scamped4 ,and as to soldered connections1 apart from the uncertainty of permanent contact1 it is very important to keep the soldering iron away from roofs1 it often damages the lead1 and 7as at ,canterbury7 the fire-pot is a source of great danger to buildings4 ,illustration3 ,,fig4 #a4 ,illustration3 ,,fig4 #b4 ,illustration3 ,,fig4 #c4 ,a is the copper tape conductor4 ,b is a screw plug1 having two slots1 a a 7see fig4 #c71 and an intervening division b1 all cast in one piece4 ,the tape or rope ,a is passed through one of the slots a1 and bent over the division piece b1 the bent portion ,a#a is then returned through the other slot4 ,a screw socket forming the coupling ,c1 bearing a collar to rest in a ring bolt built into the structure to be protected1 is then screwed on to the plug ,b1 and into this socket the rod or tube ,d is screwed1 it being suitably tapped for its reception1 until the lower end of the rod or tube is in firm contact with the tape or rope4 ,these latter are then firmly held together1 and cannot by any possibility come apart4 ,,note4--,in fig4 #b the rod and tape are not shown in actual contact1 the drawing being intended to exhibit the separate parts4 ,r4 ,c4 ,,cutting ,co4 #adg1 ,,queen ,,victoria ,,street4 99 99 99 99 99 ,i have the pleasure of furnishing details of the recent damage to ,christ ,church1 at ,carmarthen4 ,the circumstances are these3 ,at the ,eastern end of the church stands an ordinary square tower1 covered with a sloping slated roof2 this roof is capped by an ornamental open ironwork ridging1 terminating at each end in a light open iron pinnacle1 and having in the centre another pinnacle similar to those at the extremities4 ,a is a view of this ironwork from the east end of the church4 ,the conductor consisted of seven copper ropes stranded together1 each rope consisting of seven strands of ,no4 #ah wire1 the whole having a diameter of about an inch4 ,it was fixed to the building by ordinary copper staples2 it ran up1 and was attached to the southern portion of the ornamental railing1 and it terminated in a single point4 ,there was no special connection between the conductor and the iron guttering of the church4 ,i could not ascertain in what manner the earth was made1 but it was an imperfect one1 giving a resistance of #aae ohms1 and this resistance would have been greater but for an accidental circumstance mentioned further on4 ,the lightning struck the central iron pinnacle of the ornamental ridge and broke it off4 ,in falling to the ground it was shattered into about twenty pieces2 but on the upper extremity1 which was a solid cast-iron spike1 about inch square1 there were marks of fusion across the whole of the top to the depth of th of an inch4 ,i could not observe other marks of fusion at the point where the pinnacle was broken off1 but the lightning made its way to the conductor1 and on reaching the ground1 at a distance of #d feet from the point where it entered1 it burst out with explosive violence1 blowing a circular hole in the ground #b feet in diameter and #h inches deep 7marked ,b in plan74 ,the earth from this hole was blown into the air1 and fell in a fine shower on objects standing #c or #d feet high and #ad or #ae feet from the hole4 ,illustration3 ,,christ ,,church1 ,,carmarthen4 ,a second flash struck the iron guttering at the south-western extremity of the church 7,c71 broke off a #b feet length1 and ran down the waterspouts 7,d ,d74 ,opposite one of these a second hole1 #i inches deep and a foot in diameter1 was blown out of the ground1 some #c feet from the base of the spout4 ,on examining more closely the surroundings of the lightning conductor1 ,i observed that the church gas-pipe1 an iron one1 about #a inches in diameter1 passed through the wall of the building about #f feet from the conductor1 and was carried in a direction corresponding with the hole caused by the explosion 7see plan74 ,i immediately concluded that this explosion was due to the current breaking across from the conductor to the gas-pipe1 and on opening up the hole ,i found this to be the fact4 ,the conductor crossed the gas-pipe at nearly a right angle1 being about a foot above it4 ,the under portion of the conductor bore evident marks of fusion1 and1 more interesting still1 the gas-pipe was slightly coated with a very thin deposit of copper1 so thin that it perished in my attempt to remove it2 but still there was an undoubted coating at one spot4 ,but for the proximity of the conductor to the gas-pipe1 the earth resistance of the former would doubtless have been greater than it was1 and the damage would probably have been increased4 ,i was sorry that no means existed for examining the ornamental ridge1 but doubtless the metallic contact between the sections was very imperfect1 and to this cause was due the rupture of the pinnacle4 ,the fact1 too1 that the protector did not prevent the south-western portion of the building being struck bears on the question of the area made safe by a protector4 ,the tower stood #hi feet above the ground1 the top of the iron pinnacle #ii feet1 and the protector extended #a foot #f inches above the latter1 thus reaching a total height of #ajj feet #f inches4 ,the total length of the church was #abc feet4 ,the point ,c where the gutter was struck was #hd feet in a direct line from the conductor1 and stood #bd feet above the ground4 ,this gives a vertical height of the conductor of #gf feet #f inches above the point struck1 the distance of the latter being a radius #h feet greater than the height of the former4 ,j4 ,,gavey4 ,,cardiff1 ,january #ajth1 #ahhj4 ,,accident ,,at ,,bootham ,,bar1 ,,york1 ,,compiled ,,from ,,notes ,,and ,,measurements ,,taken ,,by ,j4 ,,edmund ,,clark4 ,the discharge occurred about #c a4m41 #bbnd ,june1 #ahgf4 ,the principal injury occurred to the bracket lamp at ,a4 ,this lamp1 which was an ordinary street one1 was supported by an iron bracket #b ft4 #f in4 long1 and #aa ft4 #f in4 above the pavement4 ,the gas was conveyed to it by #aa ft4 #f in4 of vertical iron gas barrel1 and thence to the burner by about #c ft4 of ordinary in4 composition pipe4 ,the glass of the lamp was not broken1 but about #ah inches of the composition piping was twisted and split open as with a sharp knife1 and the other #ah inches was melted2 the gas was ignited and burning from the top of the iron barrel1 thus producing a large flame which ignited the house to which it was fixed4 ,that part of the lead pipe which was inside the lamp was uninjured1 whence it would appear that the point struck was at or near to the top of the iron gas barrel2 and this is supported by the fact that the lead over the shop window and close to the bracket was turned up off the wood-work4 ,the lamp1 as will be seen by the plan1 is attached to the corner of a house1 the eaves of which were #bj ft4 above the lamp1 while the ridge1 with a little lead flashing1 was #bd ft41 and the chimney pots were #ca ft4 above the lamp1 and not #ae ft4 distant horizontally4 ,this house was slated and had wood gutters1 and an iron rain-water pipe1 but the latter was #cc ft4 horizontally from the point struck4 ,the wooden gutters were very old and rotten1 and one of them was very slightly shifted2 it is not certain that this was done by the lightning1 and there was no other indication of its presence4 ,c is a lamp bracket extending #d ft4 from the wall of the house1 and at ,d are two old iron brackets4 ,at the distance of only #h ft4 from the lamp in the opposite direction 7,n4,w4 of the lamp7 rises ,bootham ,bar1 a massive stone structure1 of which the four turrets rise to #dd ft4 #c in4 above the pavement1 and therefore #cc ft4 above the lamp4 ,the whole roof1 about #gej square feet1 is covered with thick sheet lead1 and the building also contains the old portcullis ,b heavily shod with iron4 ,the noteworthy feature of the case appears to be1 that the only injury is found at a spot surrounded by objects close to it1 and greatly exceeding it in height2 in fact1 that the lightning dipped into a sort of cavity1 instead of striking at the higher objects4 ,it is evident that in this case1 although the composition pipe was melted1 the iron one afforded ample conduction1 and the city gas mains a perfectly safe earth terminal4 ,illustration3 ,,south-,,east ,,view ,,of ,,bootham ,,bar4 ,,accident ,,at ,,bootham ,,bar1 ,,york4 ,illustration3 ,,view ,,of ,,house ,,and ,,section ,,of ,,bar4 ,illustration3 ,,ground ,,plan ,,of ,,houses ,,and ,,of ,,bar4 ,,references4 ,a ,gas bracket struck4 ,b ,iron sheathed portcullis4 ,c ,old gas bracket4 ,d ,old ,iron brackets4 ,,appendix ,j4 ,,data ,,respecting ,,the ,,sectional ,,area ,,of ,,metal ,,requisite ,,for ,,lightning ,,conductors4 7,n4,b4--,in order to avoid confusion1 all areas of iron have been reduced to th of their actual sizes1 so that virtually tables ,i4 and ,,ii4 may be regarded as giving all details for copper--but the metal is specified in each case47 ,,table ,i4--,,list ,,of ,,metals ,,melted4 ,material ,form ,size ,,remarks ,diameter4,area of ,copper4 in4 in4 ,,copper ,rod #ce #aj ,duprez1 ,app41 p4 #ib ,,copper ,rope#ca #jge ,at ,nantes1 ,callaud's ,trait1 p4 #hi #f,not ,specified4,rope #jg ,at ,carcassone1 ,callaud's ,trait1 p4 #hi ,,iron ,rod #jc ,harris on ,thunderstorms1 p4 #aji ,,brass ,rod #bj #jc ,duprez1 ,app41 p4 #ib ,,copper ,rod #ac8 #ja8 ,sullivan1 ,app41 p4 #aie ,footnote #f3 ,assumed to have been ,iron1 the dimension given is 8#ah mm40 #gj in4 diam41 or #ch in4 area4 ,,table ,,ii4--,,remarks ,,respecting ,,dimensions4 ,material ,form ,size ,,remarks ,diameter ,area of ,copper4 in4 in4 ,,copper ,rod #fa ,trinity ,house smallest1 ,app41 p4 #ahc ,,copper ,rod #ge #dd ,will carry any flash1 ,harris on ,thunderstorms1 p4 #aae ,,copper ,rod #ej #bj ,never yet failed1 ,faraday1 ,app41 p4 #hi ,,copper ,tube #bj ,war ,office smallest1 ,app41 p4 #gj ,,copper ,tape #ai ,gray ,son's smallest1 ,app41 p4 ,,iron ,rod #af ,never affected1 ,franklin1 ,app41 p4 #eb ,,copper ,any #aa ,recommended by ,phin1 ,app41 form p4 #ajc ,,iron ,rod #aa ,more than sufficient1 ,gay ,lussac1 ,app41 p4 #eh ,,copper ,rope#ch #aa ,recommended by ,callaud1 ,app41 p4 #ajd ,,copper ,tape #ji ,freeman ,collier's smallest1 ,app41 p4 #aj ,,iron ,rod #jh ,never known to be melted1 ,pouillet1 ,app41 p4 #fb ,,iron ,rod #jh ,should not be less1 ,henry1 ,app41 p4 #ii ,,copper ,rope#ci #jf ,carried off heavy discharge1 ,callaud ,trait1 p4 #hi ,,iron ,rod #jf ,recommended by ,callaud1 ,app41 p4 #ajd ,,iron ,rod #jf ,recommended by ,mohn1 ,app41 p4 #ajg ,,copper ,rod #be #je ,recommended by ,mohn1 ,app41 p4 #ajg ,,iron ,rod #jd ,recommended by ,phin1 ,app41 p4 #ajc ,,copper ,rod #bj #jc ,recommended by ,zenger1 ,app41 p4 #ajf ,,iron ,rope #jb ,recommended by ,mann1 ,app41 p4 #ajh ,,iron ,wire #ja ,sufficient for any house1 ,preece1 ,app41 p4 #aja ,,dimensions ,,of ,,lightning ,,rods--,,copper4 ,partly extracted from the ,appendix at the pages quoted1 and partly compiled from specimens collected by the ,conference1 and from trade circulars4 ,weight,remarks1 and ,pattern ,diameter,breadth,thickness,superficies, area per ,references foot to ,appendices4 ,inches ,inches ,inch ,inches ,inch oz4 ,ext4 #a ,ext4 #dga ,sir ,w4 ,snow ,,tube ,int4 #a ,int4 #cad #ih #fj ,harris 7#di7 ,trinity ,,hemicylinder #a #chf #hh #ed ,house1 ,mains 7#ahc7 ,trinity ,,hemicylinder #a #cba #fa #cg ,house1 ,branches 7#ahc7 ,freeman ,,tape #c #c_/af #fch #ef #cd ,collier's largest 7#aj7 ,,tube ,ext4 #a ,ext4 #dga #ed #cc ,int4 #a ,int4 #cic ,faraday preferred ,,rod #bce #dd #bg this to smaller 7#hi7 ,gray ,son's ,,tape #c #fbe #cg #bc largest 7#g7 ,,tube ,ext4 #a ,ext4 #cad #cd #ba ,int4 ,int4 #bcf ,sanderson's ,,tape #b #dbe #be #ae largest 7#bc7 ,,tape #a #ae #ccj #bc #ad ,war ,office 7#gj7 ,,rod #aeg #bj #ab ,sir ,w4 ,snow ,harris 7#di7 ,war ,office 7#gj7 ,,tape #a #cbe #ai #ab 8,smallest desirable0 ,gray ,son 7#g7 ,,tube ,ext4 ,ext4 #aif #bj #ab,war ,office ,int4 ,int4 #aah 7#gj7 ,,tape #b #a_/af #eab #ae #i;,j4 ,davis ,son 7#ad7 ,,rope 7#di ,pennycook square #ajgh #ae #i ,co4 wires7 ,,tape #b #a_/af #dab #ac #h ,,tape #a #bbe #ac #h,phin1 of ,new ,york 7#ajc7 ,massingham ,,rope 7#di #hjj8 #aj #f 7#ae7 wires7 ,newall's ,rope ,,tape #a #a_/af #cab #ji #f ,freeman ,,tape #age #ji #f ,collier's smallest 7#aj7 ,ext4 ,ext4 #bge ,,tube ,int4 #a_/cb ,int4 #bee #jh #e #ac_/af ,,rope 7#cf wires #g_/af #ejj8 #jh #e;,j4 ,davis hemp ,son 7#ad7 centre7 ,,spratt',s ,,patent #a #deb #jh #e ,,plait 7#bj wires7 ,,tape #a #a_/af #bab #jf #d ,,rope 7#di #fjj8 #jf #d,newall's wires7 ,rope ,sanderson's ,,tape #a_/ab #adb #je #c smallest 7#bc7 ,,spratt',s ,,patent #a #caf #je #c ,,plait 7#ad wires7 ,,hart',s ,,plait 7#ac copper wires and #cjh #je #c #a zinc one7 ,,appendix ,k4 ,,notes ,,respecting ,,lightning ,,conductors1 ,,collected ,,in ,,paris ,,in ,,may1 #ahha1 ,,by ,,messrs4 ,,preece ,,symons4 ,the information which we obtained may perhaps be most conveniently grouped under the names1 arranged in alphabetical order1 of the authorities whose opinions or whose practice we quote4 ,these gentlemen are ,m4 ,androut1 who1 under the direction of ,m4 ,alphand1 the ,city ,engineer1 has charge of all the lightning conductors attached to the municipal buildings of ,paris1 ,m4 ,borrel1 of #dg1 rue des ,petits ,champs1 who has been making lightning conductors nearly all his life1 ,m4 le ,comte du ,moncel1 who is well known as perhaps the highest authority in ,france upon the practical application of electricity1 and lastly ,m4 ,jarriant who is manufacturer to the municipality1 and also1 we believe1 to the ,war ,department1 besides having a large connection among architects and engineers4 99 99 99 99 99 ,m4 ,,androu,t accompanied us in a thorough examination of the conductors as they are now fixed upon the south gallery of the ,louvre1 temporarily occupied as the ,hotel de ,ville de ,paris4 ,they were stated to be only temporarily fixed1 because the offices of the ,prfet of the ,seine will be removed to the new ,hotel de ,ville as soon as it is rebuilt1 but they were said nevertheless to be in almost all respects conformable to the instructions issued by the municipality4 ,the tiges were iron rods1 #aj m4 7#cc feet7 high1 with rather blunt terminals of gilded copper2 they were #ce m4 7#aae ft47 apart4 ,all were united by a horizontal copper rope1 inch diameter 7used instead of iron bars #jh in4 square1 because of the temporary nature of the work71 which was led along the roof through iron holdfasts or crutches1 which were carefully soldered to the metal roof4 ,all joints in the rope were spliced and heavily soldered4 ,for sthetic reasons the main conductor is carried down inside the building1 through various closets1 c41 and finally1 after a rather circuitous course1 it finds its earth terminal in a plate of copper #a m4 7#c ft4 #c in47 square1 immersed in the ,seine4 ,although the roof is well covered with metal no separate connections with earth are made4 ,m4 ,androut tests the conductivity from every tige in the spring of each year1 using a very portable apparatus1 consisting of two ,leclanch's cells and a trembling bell4 99 99 99 99 99 ,m4 ,,borrel showed us various specimens of conductors1 of earth terminals1 and also his portable testing apparatus4 ,he also gave us a copy of the ,instruction sur les ,paratonnerres1 which he issues1 and from which we make a few extracts1 especially as in several respects ,m4 ,borrel's views are expressed with unusual clearness1 and although in holding some of them he stands alone3 8,a lightning conductor is a preventive agent destined to convey to moist earth1 or preferably to water1 the electricity contained in a cloud4 ,when strong earth tension is produced by the passage of an oppositely electrified cloud1 the beneficial action of the conductor is indicated by the luminous brush discharge from the top of the conductor4 8,it is generally considered that a conductor protects a cone of revolution1 having for its base the height of the point above the roof multiplied by #age1 and for its summit the point4 ,if1 therefore1 the point be #f m4 7#bj ft47 above the roof1 it will protect a base #aj m4 7#ce ft47 radius4 ,m4 ,borrel supplies round upper terminals of galvanised wrought iron about #aj m4 7#cc ft4 high71 and tapering from a diameter of #d inches at the base to inch at the top4 8,having found that long exposure to the weather destroys iron wire ropes1 and even copper ones1 if made of many small wires1 he has adopted where ropes are necessary1 four or five rods nearly #jbj in4 diameter1 so slightly twisted as not to strain the metal4 ,by this means the numerous interstices of the ordinary ropes are avoided1 and much greater durability is insured4 8,where iron bars are used he employs galvanised wrought iron in square bars1 the sides ranging from #jfc in4 to #jij in4 8,to allow for variations of length produced by changes of temperature1 he always inserts1 in long roof conductors1 a compensator1 which is merely a loop of copper tape4 8,m4 ,borrel says that it is especially upon the earth connection that the efficacy of a conductor largely depends2 there must be a metallic mass1 with a large surface1 and he describes his pattern of #8perd fluide4' ,it is composed of two sheets of galvanised wrought iron #c ft4 long1 #f in4 wide1 and an inch thick1 hacked into sharp points in order to facilitate the discharge of the electricity4 ,he alludes to ,callaud's basket of coke1 but says that its efficiency has not been absolutely demonstrated4 ,m4 ,borrel insists upon the perd fluide being immersed in the water of a well1 and one preferably not less than #b ft4 in diameter4 ,he strongly objects to insulators1 and says that he always makes metallic connection between the gutters1 rain-water pipes1 c4 and his conductors4 ,from the surface of the earth to #f ft4 above it1 he encloses his conductor in a wooden case in order that no one may touch it during a storm40 99 99 99 99 99 ,we had a long conversation with ,m4 ,,le ,,comte ,,du ,,moncel1 of whose remarks the following is a prcis3-- ,he objects to square iron bars because their angles have a tendency to facilitate lateral discharge4 ,he objects to conductors being painted1 because he believes that the surface of a conductor acts electro-statically4 ,he knows that the brass wire rope occasionally used for lighthouses is often destroyed1 but thinks that the theory enunciated in the ,report of the ,acadmie des ,sciences1 #ahth ,december1 #ahed 7see ,appendix ,f41 p4 #fb71 can hardly be maintained1 and believes it to be more probable that the rope was in a very bad state of oxidation4 ,thinks that conductors should possess both sectional area and surface4 ,does not attach much importance to extremely sharp points1 but thinks that the suggestion of one stout central one to receive a disruptive discharge1 surrounded by three or four needles to facilitate silent discharge1 would be good4 ,the following statement was quoted from the ,report of #bjth ,may1 #ahge 7see ,appendix ,f41 page #fh71 that1 8if a conductor cannot be led either to the subterranean water or to a main water-pipe1 no lightning rod should be erected4 ,it would do more harm than good40 ,count du ,moncel said that the paragraph referred chiefly to buildings on large solid rocks1 but that obviously there is every degree of quality in the earth contact which can be obtained2 and that although it is easy to decide at the two extremes1 it is difficult to say how bad the earth must be in order to render the erection of a conductor inadvisable4 99 99 99 99 99 ,m4 ,,jarriant1 who is the manufacturer employed upon the ,municipal buildings of ,paris 7and author of two pamphlets1 of which abstracts are given in ,appendix ,f1 pages 7#aaa7 and 7#aae771 accompanied us through his works1 and afforded us all the information which we could desire4 ,he showed us a large collection of platinum points of various patterns1 ranging in cost from #abs4 to #fjs4 each2 he also showed us some which had been employed by other makers1 which were merely hollow sheaths of platinum filled in with soft metal in order to reduce the cost4 ,he had also a large variety of upper terminals1 including the patterns used by the ,city of ,paris1 by the ,war ,department for its military establishments1 and by civil engineers and architects4 ,we saw specimens of the ropes1 rods1 c41 usually supplied4 ,the iron ropes were galvanized and in4 diameter4 ,the copper ropes were made of six twisted strands of copper wire enclosing a central core of hemp1 the total diameter being an inch4 ,the iron bars were square galvanized wrought iron #jhj in4 square1 in lengths of #af feet1 rabbetted at the ends with two holes for bolts4 ,to make a joint a strip of foil is laid between the two faces1 the bolts are screwed up1 and then the whole joint is very heavily soldered4 ,among various works in progress1 we saw a highly decorated wrought iron cross for the roof of a church1 which cross would become the summit of the conductor1 its top and the extremity of each arm being furnished with a short copper terminal tipped with a platinum point4 ,we were much struck by the fact that in ,france1 where so much attention has been given to lightning protection1 there should be so much diversity of practice4 ,the ,municipality adopt one system1 the ,state another1 the ,war ,department a third1 and each individual manufacturer has1 as in ,england1 his hobby4 ,we desire to record our thanks to ,mr4 ,j4 ,aylmer1 ,c4,e41 for making the various arrangements1 by which we were able to see so much in the comparatively short time at our disposal1 and also for accompanying us throughout4 ,w4 ,h4 ,,preece4 ,g4 ,j4 ,,symons4 ,p4,s4--,a very convenient form of a rough testing apparatus has been made1 by the ,silvertown ,co41 for one of the writers2 it consists of one ,leclanch cell1 a trembling bell1 a key1 and a pair of terminals to attach insulated wires to the top and bottom of the lightning rod1 all fixed in a neat portable mahogany box1 and with its aid any one can readily examine the conductivity of his lightning rod4 ,,appendix ,l4 ,,on ,,the ,,lightning ,,conductors ,,at ,,the ,,paris ,,international ,,electrical ,,exhibition1 ,,by ,,messrs4 ,,dymond ,,and ,,symons4 ,it was hoped that at the ,paris ,electrical ,exhibition would be found examples of the various styles and patterns of lightning rods used in the several countries of ,europe and in the ,united ,states1 and we accordingly visited the ,exhibition and inspected all the exhibits in any way relating to the subject4 ,those from ,france were naturally the most numerous 7#ae71 but there were some very elaborate specimens of the system adopted in ,belgium1 in accordance with the recommendations of ,m4 ,melsens2 and there was also sent by ,dr4 ,weber1 of ,kiel1 a very interesting collection of #ab points which had been struck by lightning1 all more or less fused and damaged4 ,the ,french exhibitors showed a great variety of points1 but they were for the most part referable to two or three types or classes1 and only varied in size4 ,the favourite form appeared to be that shown by ,fig4 #a1 a rather finely tapering brass rod terminated by an acornshaped piece1 from the upper end of which projected a small needle4 ,they were constructed to be screwed to the top of the iron tige4 ,they varied in size from #a ft4 long and in4 diameter at the base1 tapering to in4 at the acorn1 to #b ft4 #f in4 long and #a in4 diameter1 tapering to in4 ,the acorns were generally about twice the diameter of the point to which they were joined1 and were about #a diameter long4 ,the needles were always made of platinum about #a in4 long and #a in4 diameter4 ,some exhibitors showed a very similar pattern1 but made in copper instead of brass4 ,there were also several specimens of blunt points in copper--the ,point ,municipal1 ,fig4 #b1 tapering from #a in4 to in4 diameter and #a ft4 #h in4 long2 tapering brass and iron rods1 some of them having platinum cones1 were also exhibited4 ,all these points were intended to be mounted on exceedingly long upper terminals4 ,the conductors were generally made of wire rope1 copper1 brass1 or galvanized iron1 and in the majority of cases composed of strands of small wires1 though there were a few specimens of ropes made of large wires 7say7 #a in4 in diameter2 and there were also some specimens of conductors made of iron bars with copper expansion bands4 ,these last specimens were about #h in4 square1 but almost all the ropes seemed to us too small1 generally about #d in4 diameter1 and we were surprised to see that the iron ropes were no larger than the copper or brass ones4 ,illustration3 #d ,illustration3 #c ,illustration3 #b ,illustration3 #a ,the methods adopted for joining them to the upper terminals were either to push the end into a socket and pin them across1 or more frequently to tie them more or less loosely round the base4 ,the practice as to insulation seemed to vary1 some makers supplying insulators and others not1 but they almost all provided for carrying the conductor from #f to #i in4 away from the face of the building4 ,there were but few specimens of earth plates1 they were in the form of grapnels1 and seemed very inadequate2 not one would afford #c superficial feet of earth contact4 ,some models and drawings showed that the ,french electricians assumed a cone of protection whose radius was at least #age of its height4 7,see ante page 7#fg747 ,excepting ,france the most numerous series of exhibits was that from ,belgium1 which also contained a complete model of the monument erected at ,lacken in memory of ,leopold ,i41 showing the manner in which it had been fitted with conductors under the superintendence1 or according to the system1 of ,m4 ,melsens4 ,the monument referred to is a ten-sided ,gothic building1 with pinnacles on two storeys and a spire4 ,on the top of the spire1 but below the figure1 is a considerable number of radiating points1 and there is a similar frill round the top of each of twenty pinnacles4 ,each aigrette consists of seven copper points1 each about #jd in4 in diameter and #b ft4 long1 tapering to a very sharp point2 they are all leaded into a collar or band encircling the stone work2 and from them go the rods about #jd in4 in diameter1 which are first taken into a cast iron box about #h in4 #e in4 #b in42 into this box are also taken rods which lead to connections with 7#a7 a well1 7#b7 the water mains1 and 7#c7 the gas mains4 ,when these two series of rods are all in position in the box it is filled with melted lead1 and thus perfect connection is secured4 ,there were specimens of the aigrette1 and also of the manner of joining the rod to the gas and the water mains1 and to the large iron pipe which is sunk in the well4 ,this is effected by bringing all the rods parallel with the main1 and arranging them1 at equal distances from each other1 around it4 ,they are then held tightly to it by two semicircular clamps bolted together1 and melted lead is poured in and caulked4 ,the main1 and probably the inside of the clamps1 was filed bright when the joint was made4 ,the other exhibits--patterns of points and conductors--do not call for any special mention1 but we may notice that the ,belgian makers were generally much more careful than the ,french to make good electric contact at the joints1 and some conductors were exhibited cut through the joints to show the care bestowed in this particular4 ,from ,germany were sent some specimens of wire rope for conductors1 made of the usual strands of small wires4 ,the iron ropes were slightly larger and of slightly larger wires than the copper1 but the former were not more than #jf in4 in diameter4 99 99 99 99 99 ,dr4 ,,weber1 of ,kiel1 exhibited a collection of #ab points1 all which have been struck by lightning--their length varies from #d in4 to #g in41 they are of gilded copper1 about #a in4 in diameter at the thickest point1 and vary in the acuteness of their extremities--some have platinum needles1 about #jjh in4 diameter1 screwed into their points2 these needles have1 in most cases1 been wholly fused4 ,in some cases the platinum is somewhat thimble-shaped1 and fitted over the copper--in these cases the platinum is generally wholly melted1 and the copper uninjured4 ,platinum of #jab in4 diameter has been melted1 but there is not one of these points of which copper of that size has been fused4 ,there is no indication that these points have been fixed to tiges--on the contrary1 they are all hollow at the base1 and have had soldered into them copper ropes1 none exceeding #jcc in4 diameter1 and most of them consisting of three strands of six wires each 7#ah wires71 the wires being about ,no4 #ah ,b4,w4,g4 ,there were a few specimens of gilded copper points1 sent from ,austria1 such as ,fig4 #c2 and our ,english makers also sent a few examples of points1 the crow foot1 ,fig4 #d1 for instance1 of upper terminals1 and of rope and tape conductors4 ,e4 ,e4 ,,dymond4 ,g4 ,j4 ,,symons4 ,,appendix ,m4 ,,miscellaneous4 ,,means ,,to ,,be ,,adopted ,,for ,,ensuring ,,personal ,,safety ,,from ,,the ,,effects ,,of ,,lightning4 7,abstracted by ,prof4 ,g4 ,carey ,foster1 ,f4,r4,s47 ,,works ,,consulted3-- ,received from the ,correspondence addressed to ,lightning ,rod ,secretary of ,conference4 ,lightning ,rod ,conference4 ,directions for ,insuring ,personal ,safety during ,storms of ,thunder and ,lightning2 and for 99 99 99 ,by ,john ,leigh1 pp4 #fj4 ,london 7no date74 ,benjamin ,franklin4 ,complete ,works4 #c vols4 #hvo4 ,london1 #ahjf4 ,gehler4 ,physikalisches ,wrterbuch4 ,article 8,blitz10 ,leipzig1 #ahbe4 ,franois ,arago4 ,meteorological ,essays1 from the ,french by ,sabine4 ,london1 #ahee4 ,c4 ,kuhn4 ,handb4 d4 angewandten ,elektricittslehre4 ,leipzig1 #ahff4 ,the danger to men and animals from the effects of lightning arises from the fact that the bodies of living animals form comparatively good conductors of electricity1--better1 that is1 than rain-water 7probably better even than sea-water71 or than trees1 walls of brick or stone1 hay-stacks1 or in fact than almost any common objects consisting of non-metallic materials4 ,it may be assumed that the path of a lightning-discharge striking the earth is determined by the line of least inductive resistance between the thunder-cloud and the earth4#g ,hence1 a man standing on an open plain1 or walking1 or riding on horseback1 or in an open vehicle1 across it1 is liable to be struck by lightning4 ,there is no evidence that the motion of walking or riding makes the liability either greater or less than it would be if he were at rest4 ,the danger is increased1 other conditions being the same1 by nearness to water1 or to large masses of metal1 or other conducting material1 lying flat on the ground or rising only a little way from it4 ,an umbrella held over-head is probably dangerous1 but ,i do not find direct evidence that it is so among recorded cases4#h ,such small metallic articles--money1 keys1 c41--as may be commonly carried in the pocket1 have probably no perceptible effect4 ,in the open country1 beyond the reach of shelter1 low-lying positions1 if dry1 are safer than those which are more elevated and exposed2 but1 on the other hand1 water-courses are to be avoided4 ,it is also safer to lie flat on the ground than to stand or sit4 ,if shelter is within reach1 care should be taken to get completely under cover4 ,there is often much more danger in standing under the lee of a house1 or wall1 or hay-stack1 or thicket of trees1 than in remaining quite exposed4 ,there is but little danger1 however1 inside a barn or outhouse1 as far as possible from the walls1 or underneath a wagon or the arch of a bridge4 ,the inside of a wood is also a tolerably safe situation if we keep clear of the branches of the trees and as far as may be from their trunks4 ,if isolated trees afford the only shelter within reach1 it is advisable to go near them 7within two or three yards of their projecting branches7 but not under them4 ,leaning against the trunk of an isolated tree during a thunderstorm is very dangerous4 ,in this case the danger arises from the fact that the tree is a much better conductor than the air surrounding it1 though a worse conductor than the human body4 ,hence1 if a man stands against a tree1 a line of least inductive resistance is likely to be determined through his body and continued upwards through the tree4 ,like considerations apply in the case of a person standing against a wall1 or other high object1 consisting of very imperfectly conducting materials and unprovided with efficient lightning conductors4 ,footnote #g3 ,the apparently capricious way in which lightning often strikes is not inconsistent with this statement4 ,it proves1 however1 that the line of least inductive resistance is partly determined by atmospheric or terrestrial conditions which are not perceived by the eye4 ,footnote #h3 ,is there any evidence to show that soldiers wearing spiked helmets1 or marching with fixed bayonets1 are specially liable to be struck by lightning8 ,various ancient writers--,csar1 ,seneca1 ,livy1 ,pliny1 and others--mention luminous appearances 78,fire of ,st4 ,elmo07 presented by the javelins or pikes of soldiers during thunderstorms at night4 ,as to people indoors1 we need only consider the case of those who are in buildings which are either not at all or only imperfectly protected by conductors2 for1 if a building is thoroughly protected1 whatever is inside it is protected also4 ,indoors1 as out of doors1 we have to avoid forming part of a line of least inductive resistance4 ,this consideration leads to such rules as the following3--,keep to the lower rooms of a house1 rather than to the upper rooms2 also keep as much as possible in the middle of the room you are in1 but avoid being under a metal chandelier1 or a lamp1 or other object hung by a metal chain or wire2 keep away from a stove or fire-place1 especially when a fire is burning in it2 keep away from large metallic objects which are not in electrical connection with the ground1 especially if they are above the level of the head 7as mirrors1 or pictures with gilt frames1 hung against the wall71 or below the feet 7as an iron pillar or beam supporting the floor1 or an iron staircase leading to a lower storey but not continued to one above74 ,franklin recommends 8sitting in one chair and laying the feet up in another10 or as a further precaution 8to bring two or three mattresses or beds into the middle of the room1 and1 folding them up double1 to place the chair upon them40 ,but best of all he says is1 8where it can be had1 a hammock1 or swinging bed suspended by silk cords equally distant from the walls on every side1 and from the ceiling and floor above and below40 ,doors and windows are better shut than open1 but it does not seem that this condition is of much importance4 ,it may be added for the comfort of the timid that ,arago concludes that the danger of being struck by lightning in a town 7,paris7 8is less than the danger of being killed in passing along the street by the fall of a chimney1 or flower-pot1 or of a workman engaged upon a roof2 this latter danger being he imagines one which occasions very little uneasiness40 ,also it seems to be the universal testimony of those who have been restored after being struck by lightning that they had not been conscious of either thunder or lightning4 ,we may accordingly conclude that all danger from a given discharge is over1 not merely by the time we hear the thunder1 but as soon as ever we see the flash4 ,g4 ,c4 ,f4 ,,injury ,,to ,,gas ,,and ,,water-,,pipes ,,by ,,lightning4 ,the city gas company of ,berlin1 having expressed the fear that gas-pipes may be injured by lightning passing down a rod that is connected with the pipes1 ,professor ,kirchhoff has published the following reply3-- 8,as the erection of lightning-rods is older than the system of gas and water-pipes as they now exist in nearly all large cities1 we find scarcely anything in early literature in regard to connecting the earth end of lightning-rods with these metallic pipes1 and in modern times most manufacturers of lightning-rods1 when putting them up1 pay no attention to pipes in or near the building that is to be protected40 ,kirchhoff is of the opinion1 supported by the views of a series of professional authorities1 that the frequent recent cases of injury from lightning to buildings that had been protected for years by their rods1 are due to a neglect of these large masses of metal4 ,the ,nicolai ,church1 in ,griefswald1 has been frequently struck by lightning1 but was protected from injury by its rods4 ,in #ahgf1 however1 lightning struck the tower and set it on fire4 ,a few weeks before1 the church had had gas-pipes put in it4 ,no one seems to have thought that the new masses of metal which had been brought into the church could have any effect on the course of the lightning1 otherwise the lightning-rods would have been connected with the gas-pipes1 or the earth connection been prolonged to proximity with the pipe4 ,a similar circumstance occurred in the ,nicolai ,church in ,stralsund4 ,the lightning destroyed the rod in many places1 although it received several strokes in #ahef1 and conducted them safely to the earth4 ,here1 too1 the cause of injury was in the neglect of the gas-pipes1 which were first laid in the neighbourhood of the church in #ahef1 shortly before the lightning struck it4 ,the injury done to the school-house in ,elmshorn1 in #ahgf1 and to the ,st4 ,lawrence' ,church1 at ,itzehoe1 in #ahgg1 both buildings being provided with rods1 could have been avoided if the rods had been connected with the adjacent gas-pipes4 8,if it were possible10 says ,kirchhoff1 8to make the earth connection so large that the resistance which the electric current meets with when it leaves the metallic conducting surface of the rod to enter the moist earth1 or earth water1 would be zero1 then it would be unnecessary to connect the rods with the gas and water-pipes4 ,we are not able1 even at immense expense1 to make the earth connections so large as to compete with the conducting power of metallic gas and water-pipes1 the total length of which is frequently many miles1 and the surface in contact with the moist earth is thousands of square miles4 ,hence the electric current prefers for its discharge the extensive net of the system of pipes to that of the earth connection of the rods1 and this alone is the cause of the lightning leaving its own conductor40 ,regarding the fear that gas and water-pipes could be injured1 the author says3 8,i know of no case where lightning has destroyed a gas or water-pipe which was connected with the lightning-rod1 but ,i do know cases already in which the pipes were destroyed by lightning because they were not connected with it4 ,in ,may1 #ahji1 lightning struck the rod on ,count ,von ,seefeld's castle1 and sprang from it to a small water-pipe1 which was about #hj metres from the end of the rod1 and burst it4 ,another case happened in ,basel1 ,july #i1 #ahdi4 ,in a violent shower one stroke of lightning followed the rod on a house down into the earth1 then jumped from it to a city water-pipe1 a metre distant1 made of cast iron4 ,it destroyed several lengths of pipe1 which were packed at the joints with pitch and hemp4 ,a third case1 which was related to me by ,professor ,helmholtz1 occurred last year in ,gratz4 ,then1 too1 the lightning left the rod and sprang over to the city gas-pipes2 even a gas explosion is said to have resulted4 ,in all three cases the rods were not connected with the pipes4 ,if they had been connected the mechanical effect of lightning on the metallic pipes would have been null in the first and third cases1 and in the second the damage would have been slight4 ,if the water-pipes in ,basel had been joined with lead instead of pitch1 no mechanical effect could have been produced4 ,the mechanical effect of an electrical discharge is greatest where the electric fluid springs from one body to another4 ,the wider this jump the more powerful is the mechanical effect4 ,the electrical discharge of a thunder cloud upon the point of a lightning rod may melt or bend it1 while the rod itself remains uninjured4 ,if the conductor1 however1 is insufficient to receive and carry off the charge of electricity1 it will leap from the conductor to another body4 ,where the lightning leaves the conductor its mechanical effect is again exerted1 so that the rod is torn1 melted1 or bent4 ,so1 too1 is that spot of the body on which it leaps4 ,in the examples above given it was a lead pipe in the first place1 a gas-pipe in the last place1 to which the lightning leaped when it left the rod1 and which were destroyed4 ,such injuries to water and gas-pipes near lightning-rods must certainly be quite frequent4 ,it would be desirable to bring them to light1 so as to obtain proof that it is more advantageous1 both for the rods and the building which it protects1 as well as for the gas and water-pipes1 to have both intimately connected4 ,finally1 ,i would mention two cases of lightning striking rods closely united with the gas and water-pipes4 ,the first happened in ,dsseldorf1 ,july #bcrd1 #ahgh1 on the new ,art ,academy2 the other ,august #aith1 last year1 at ,steglitz4 ,in both cases the lightning-rod1 the buildings1 and the pipes were uninjured40--,deutschen ,bauzeitung4 ,quoted in ,the ,building ,news1 ,sept4 #aj1 #ahhj4 ,,colliery ,,workings ,,struck ,,by ,,lightning4 ,,the ,,institute ,,of ,,mining ,,engineers4 ,a meeting of the members of the ,north of ,england ,institute of ,mining and ,mechanical ,engineers took place in the ,wood ,memorial ,hall on ,saturday1 ,mr4 ,g4 ,c4 ,greenwell in the chair1 when the secretary read an account of an investigation which had been made into a statement that lightning had entered ,tanfield ,moor ,colliery on the #abth of ,july last1 and traversed the workings in several directions4 ,mr4 ,wm4 ,joicey kindly gave permission to examine the witnesses of the occurrence1 and the workings of the colliery1 so that a complete and accurate report could be drawn up of the circumstance2 and on the #cjth of ,july1 ,mr4 ,c4 ,berkley1 ,mr4 ,j4 ,b4 ,simpson1 ,mr4 ,w4 ,h4 ,hedley1 and the secretary went out to the colliery1 and were met by ,mr4 ,w4 ,joicey1 one of the owners2 ,mr4 ,pringle1 the viewer2 and ,mr4 ,arkless1 the resident viewer4 ,the top of the working shaft at the colliery is #cd fathoms from the ,shield ,row seam4 ,an incline bank leads northwards from the working shaft and ultimately reaches the day by a drift1 and a little to the south is an up-cast shaft4 ,the engine way leads south from the working shaft1 and goes in-bye to a goaf4 ,between the goaf and the working shaft are two down-cast shafts4 ,from what can be gathered the lightning passed down the working shaft and struck the flat sheets1 and then divided itself into two parts1 one of which went north up the incline way and probably passed out to the day by the drift1 where it was supposed to have left traces of its exit in marks upon a bank near by4 ,the other part went south along the engine way2 but after passing a point where it was noticed its further course was not known4 ,the thill of the seam is composed of soft sagger1 and the roof of strong post1 both of which would offer great obstruction to the absorption of the electric fluid2 and the probability was that this portion of the fluid had been dissipated in the goaf1 or had forced an exit by way of the down-cast shaft4 ,the evidence taken was appended4--,joseph ,kirtley1 back-overman1 said a light1 distinct but not very bright1 fell and struck the flat sheets1 and split up into several lights like a lot of lighted matches4 ,he could only see the light for a moment among the tub wheels4 ,it struck the puller-out1 ,wm4 ,watson1 on the arm1 and he complained that his arm was numb1 and when he got home it was yellow from the wrist to the elbow4 ,a heavy peal of thunder was heard very distinctly almost at the same moment4 ,no injury was done either in the shaft or on the road where the lightning was said to have passed4 ,he could liken it to nothing better than a box of matches all struck at once4--,james ,offord1 onsetter1 said he heard a crack like the report of a small pistol1 and saw a light close to his feet4--,william ,watson1 puller-out at the bottom of the pit1 said he saw a flash of light come down and heard a noise like a gun3 it struck on the plate or flat sheet4 ,he saw the light divide when it struck4 ,the light when it struck was very bright1 but did not brighten up the place to any distance4--,thomas ,chrisp1 a deputy1 said he saw something like a lot of fire flying1 and thought the tram had cut the point4 ,it was as though a person had trodden upon matches and they had gone off4 ,the fire seemed a little larger than the light of a candle1 and to the best of his judgment came along the metals4--,john ,greener saw a light on the rail about the size of a candle flickering1 not steady4 ,it appeared to travel along the rail1 and as it passed the tram made a noise like the crack of a pistol1 and he thought it was matches or something on the way that was cracking4--,john ,hagan1 a putter1 said he saw the lightning come along the plates4 ,it caught him as it passed and gave him a queer feeling in the legs4 ,it made a sharp1 cracking noise in the plates like a gun4--,george ,chrisp1 a siding minder1 said he was about #ej yards from the shaft1 and heard a cracking noise1 and saw a bright light and flash of fire against the big winding sheave1 two feet diameter1 like five or six matches going off at once4 ,there were no tubs running by at the time4--,matthew ,hardy1 an engine flatter1 who was about #ajj yards along the shaft siding1 said he saw a light like a spark from a lamp1 and there was a noise like a match being struck by a tub passing over it4 ,the light appeared to be close to him on the rope1 which was running4--,it further appeared that the rails were fished2 that it was not noticed whether the lightning came down the rails or the rope2 that it was a self-acting incline2 that a noise as of a pistol or gun shot was heard when the light came to the tram2 that a similar noise was heard as the light left the tram2 and that the metallic contact might have been broken here by a fish-plate being off4 ,the gentlemen who conducted the inquiry had every reason to believe that the information thus obtained forms a valuable record of the occurrence1 and places beyond doubt the possibility of lightning penetrating into the workings of collieries4--,in the course of the discussion which followed the reading of the paper1 ,mr4 ,a4 ,l4 ,stevenson mentioned the occurrence of a similar circumstance at ,page ,bank1 about #aj years ago4--,professor ,herschell said that in order to produce an explosion the electric fluid must come in contact with a highly explosive mixture2 and the occurrence in question showed the desirability of lightning conductors at collieries1 and of the subject being investigated by mining and electrical engineers4--,cordial votes of thanks were given to the authors of the papers4--,newcastle ,daily ,journal4 ,october #eth1 #ahhj4 ,,accidents ,,by ,,lightning ,,at ,,the ,,swan ,,cotton ,,mill1 ,,chadderton1 ,,oldham4 ,,report ,,by ,j4 ,,doherty1 ,a4,s4,t4,e4 ,on ,july #acth1 #ahhj1 during a thunderstorm1 the large #djj light gas meter of this mill1 though locked up in a cellar1 and with no light near it1 exploded1 and the gas1 which is supplied through a #d-;inch main1 was ignited4 ,this was repaired1 but on ,july #eth1 #ahha1 during another thunderstorm1 precisely the same accident occurred4 ,at the request of ,mr4 ,preece1 ,f4,r4,s41 ,mr4 ,doherty1 of ,h4 ,m4 ,postal ,telegraph ,service1 went and inspected the works1 and forwarded the following report4--,,ed4 #bast ,july1 #ahha4 ,a very careful investigation of the ,swan ,mill premises has been made1 with a view of arriving at some explanation of the recent injury to the gas meter1 which was undoubtedly caused by lightning4 ,the building is a large one1 having for its internal supports a number of cast iron columns running from floor to basement1 and on the top of the building1 ,i am told1 there are numerous iron gutters2 round the various rooms are carried large iron gas pipes1 and in numerous instances this gas piping is dead against the iron caps of the columns1 thus the lightning may have struck any portion of the building1 and the current have been conveyed1 safely1 by the gas piping to the large gas meter1 where an imperfect joint 7electrically imperfect7 existed1 viz41 an india-rubber ring placed between the faces of the iron joint4 ,it is to be regretted that the connecting pipes were not on the premises at the time of my visit1 otherwise ,i could have spoken with a greater degree of certainty1 but ,i have not the slightest doubt in my own mind as to the insulating ring between the joints being the cause of rupture4 ,tests were made1 showing that the continuity of the present pipe is lessened by the existence of another india-rubber ring1 and the oxidation of the connecting screws at another joint4 ,i advised the ,directors of the ,spinning ,company to connect the outlet and inlet main pipes by iron or copper wire straps4 ,i feel convinced that if this had been done prior to #eth ,july the accident would not have occurred4 ,j4 ,,doherty4 ,,essay ,,on ,,the ,,effects ,,of ,,heavy ,,discharges ,,of ,,atmospheric ,,electricity1 ,,as ,,exemplified ,,in ,,the ,,storms ,,of ,,the ,,summer ,,of #ahdf 99 99 99 99 ,,and ,,remarks ,,on ,,the ,,use ,,and ,,application ,,of ,,lightning ,,conductors4 ,,by ,e4 ,,highton1 ,,esq41 ,c4,e4 7,transactions of the ,society of ,arts for #ahdf-dg4 ,london4 ,sm4 #dto74 7,abstracted by ,g4 ,j4 ,symons1 ,f4,r4,s47 ,the author's primary object in studying the subject was the discovery of a method of protecting telegraphic apparatus from injury and danger4 ,that has long been accomplished1 but some remarks in the ,paper seem worthy of extraction4 ,mr4 ,highton went over ,st4 ,george's ,church1 ,leicester1 a few days after it was wrecked by the lightning4 ,he says that the sexton told him that three minutes before the flash he had been tolling the curfew bell1 and1 8while in the belfry1 he noticed a kind of light on the clapper of the bell1 and heard also1 as it were1 a sort of hissing noise40 ,this seems to prove two things--7#a7 ,the fallacy of the old notion that ringing the church bells sent away thunderstorms 7see also ante1 p4 7#cg727 and 7#b7 that even very imperfect conductors1 such as this conductorless steeple1 carry off much electricity by the silent or brush discharge4--,g4 ,j4 ,s4 ,mr4 ,highton found that the leaden flashings were frequently burst up1 the lead being sometimes forced up somewhat like a miniature volcano4 ,this he attributes to the explosion of confined atmospheric air1 but obviously water converted into superheated steam would yield a greater expansive force4 ,the author quotes a case at ,water ,newton1 ,wansford1 ,northamptonshire1 where1 although the ,church had tower and spire1 and the whole roof was covered with lead1 a tree #ij feet from the spire1 and not one-third the height of the spire1 was struck1 but the ,church was not4 ,this the author attributes partly to the action of the leaves of the trees1 and partly to there being no iron or other vertical spouting to the ,church4 ,mr4 ,highton's 8,practical ,rules0 are literatim et verbatim3-- #ast4 ,where a building has any quantity of vertical metallic work1 it is quite necessary1 for its protection against ,lightning1 that it should have an artificial ,lightning ,conductor1 7unless the materials of themselves form a natural one74 #bndly4 ,it is very desirable1 that all metallic circuits1 especially those in a vertical direction1 should be metallically connected with the system of ,lightning ,conductors4 #crdly4 ,that1 in many instances1 a single insulated ,lightning ,conductor attached to a building may become positively injurious and dangerous2 as it may cause many a cloud to discharge its electric force at that point1 which would otherwise have passed over1 and poured its power in some other channel4 #dthly4 ,that1 where ,lightning ,conductors are employed1 they ought to be thoroughly well erected1 and every course or channel that the ,electric fluid has open to it carefully considered1 and a division of the charge in those quarters provided against4 #ethly4 ,that a ,lightning ,conductor1 or a system of ,lightning ,conductors1 where properly and scientifically erected1 are perfect safeguards against the effects of heavy discharges of ,atmospheric ,electricity4 ,but1 if improperly applied1 they may become a most dangerous addition to a building4 #fthly4 ,that it is essentially necessary for the safety of the public1 that all public buildings1 and especially churches1 should1 if naturally deficient in safe and secure ,lightning ,conduction1 have artificial ,lightning ,conductors erected for their protection4 ,the above are given as a few general rules4 ,it is difficult1 however1 and almost impossible1 to lay down any fixed and definite rules for the erection of ,lightning ,conductors1 to be applicable to every building2 as the very form1 shape1 and position of the building1 and the relative position of buildings in the immediate neighbourhood1 so materially affect the data for the formation of those rules4 ,in all cases1 therefore1 ,i consider it much better and safer for an ,architect to call in a person of knowledge and experience in this branch of science1 for directions for the proper erection of ,lightning ,conductors1 than to trust to any printed rules whatever on the subject4 ,that1 as it is better in cases of illness where life is in danger to call in a medical man than to apply oneself the remedies set forth in works on medicine1 so is it better1 in the protection of buildings from the disastrous effects of ,lightning1 to trust only to the opinions and directions of those who have given to this difficult branch of science their study and attention4 ,,thunderstorms4 ,,by ,,professor ,,tait1 ,f4,r4,s4 ,delivered in the ,city ,hall1 ,glasgow4 ,nature ,aug4 #abth1 #aith1 ,sept4 #bnd1 #ith1 #ahhj4 7,abstracted by ,w4 ,h4 ,preece1 ,esq41 ,c4,e41 ,f4,r4,s47 ,while a few years ago no qualified physicist would have ventured an opinion as to the nature of electricity1 now1 thanks to ,clerk-,maxwell1 electric and magnetic phenomena are regarded as mere stresses and motions of the ether1 and are brought within the resources of mathematical analysis4 ,thunderstorms are accompanied by darkness1 the result of the intense shadow of peculiar thick clouds charged with electricity1 whose height varies from #cj yards to #c miles4 ,the air is never free from electricity4 ,snow1 sleet1 hail1 and 8luminous rain0 are frequently indications of great electrification4 ,the atmospheric electric charge is usually positive1 and is probably the result of evaporation1 but clouds themselves are more generally negative4 ,lightning1 as a source of light1 is very brilliant1 comparable even with the sun1 but its duration is extremely short1 hence its intensity is about equal to that of full moon4 ,the motion of a flash cannot be detected2 hence when people say they saw a flash going upwards or downwards1 they must be mistaken4 ,it is an optical illusion4 ,the peculiar zigzag form1 occasionally bifurcated1 is that of a very large electric spark1 varied by local electrification and heat4 ,the motion of electricity is due to a difference of potential or electrical pressure4 ,the power of a machine is measured by the utmost potential it can give to a conductor1 and the time required to charge the conductor depends on its capacity4 ,the damage which can be done by a discharge is proportional to the square of the charge1 and inversely to the capacity of the receiver4 ,doubling a charge gives fourfold a shock4 ,electricity is entirely distributed on the surface of conductors4 ,the quantity per square inch of surface is the density1 and the density varies with the form of the conductor4 ,on a very elongated body1 terminating in a point1 the density becomes so exceedingly great that the outward pressure of the electricity tending to escape forces a passage through the surrounding air4 ,proper lightning rods must be surrounded with a number of sharp points1 lest one should be injured4 ,the proper function of a lightning rod is not to parry a dangerous flash of lightning3 it ought rather1 by silent but continuous draining to prevent any serious accumulation of electricity in a cloud near it4 ,hence it must be thoroughly connected with the earth4 ,at ,pietermaritzburgh1 which is well covered with lightning conductors1 thunderstorms are frequent1 but they cease to give lightning flashes whenever they reach the town1 and they begin to do so as soon as they have passed over it4 ,the violent disruptive effects produced by lightning are principally due to the sudden vaporization of moisture4 ,heated air conducts better than cold air4 ,hence the killing of flocks and herds4 ,there is little or no danger inside a thunder-cloud4 ,thunder-bolts 7so called7 are due to the vitrification of sand through which a discharge has passed4 ,the smell that accompanies lightning is due to ozone4 ,sheet lightning and summer lightning are due to the lighting up of the clouds by flashes of forked lightning not directly visible to the spectator1 sometimes even beneath the horizon4 ,thunder corresponds to the snap of the electric spark1 intensified and re-echoed from clouds and surfaces4 ,a longer zigzag flash acts successively and intermittently from portions farther and farther from the listener4 ,hence the crash1 clap1 rolling and pealing of thunder4 ,the extreme distance that it is heard is about ten miles1 although guns have been heard fifty miles4 ,fireball or globe lightning undoubtedly exists and is probably due to a species of natural ,leyden jar1 very highly charged1 which no lightning rod can destroy1 except1 perhaps1 a close net work of stout copper wires4 ,water is the chief agent in thunderstorms4 ,copious rain and hail always accompany them4 ,hot moist air precipitating its moisture as clouds as it ascends1 cooling by expansion but warmed by the latent heat of the condensed vapour is the main spring4 ,the condensation of aqueous vapour is accompanied by an enormous development of energy4 ,a fall of one-tenth of an inch of rain over the whole of ,britain gives heat equivalent to the work of a million millions of horses for half an hour4 ,the mere contact of particles of aqueous vapour with those of air produces a separation of the two electricities4 ,aqueous vapour condenses into cloud particles1 and the agglomeration of cloud particles into rain drops would enormously increase the original potential of the electrified vapour4 ,the column of smoke and vapour discharged by an active volcano gives out flashes of lightning4 ,cloud caps on mountains frequently do the same4 ,ascending currents of air mean change of density1 difference of pressure1 heat condensation1 and all the conditions required to produce a thunderstorm1 with its effects forming 8one of the most exquisite of the magnificent spectacles which nature from time to time so lavishly provides40 ,,on ,,the ,,protection ,,of ,,buildings ,,from ,,lightning4 ,,by ,,captain ,j4 ,p4 ,,bucknill1 ,r4,e4 7,abstracted by ,w4 ,h4 ,preece1 ,c4,e41 ,f4,r4,s47 ,in the first part of his paper the author popularly explains his own views of electricity1 the causes of thunderstorms1 and the purpose served by a lightning conductor4 ,he urges the theory that lightning is mostly to be feared by those who live on well conducting areas2 and that non-conducting areas1 such as chalk hills1 suffer the least1 because their inductive influence on charged clouds is less than in the former case1 even though they be on low ground4 ,points act as leaks1 warding off lightning by neutralising harmlessly the opposite electricities4 ,the trees of a forest act as a mass of points1 silently discharging thunder clouds4 ,the potential of a thunder cloud is often a million and a-half volts4 ,the function of a lightning conductor is 87first7 to attract the lightning to another spot if possible1 and 7second7 to arrange that even if the building be struck1 the work shall be given out at other portions of the path of the stroke40 ,he advocates strange views as to the space protected by a lightning conductor1 which1 if true1 would tend to show that there is no safety in lightning conductors at all1 for according to him1 the safe area rule may be upset in practice by all sorts of accidental circumstances4 ,he has1 however1 not grasped the meaning of the rule4 ,he advocates the use of iron as the best metal to use1 specifying a weight of #b lbs4 per foot4 ,he thinks wire ropes are more easily applied than rods1 ribbons1 or tubes1 and prefers a rope #ab in4 diam4 of six strands of seven ,no4 #aa ,b4,w4,g4 wire1 each round a hemp core--costing about #e;d4 per foot4 ,conductors should be specified in terms of electrical units1 viz43 #c ohms per #ajjj yards1 and be continuous4 ,every unavoidable joint should be soldered4 ,he has found in practice many bad joints1 especially in copper conductors4 ,at ,tipner one gave #aj1jjj ohms1 and one in the ,isle of ,wight #gjj ohms4 ,each joint was apparently quite sound4 ,he considers that lofty conductors require no additional conductivity per unit of length1 and that high lightning rods are only required in exceptional situations4 ,several points are preferable to a single point1 because the 8gathering power0 is increased thereby1 and the chance of lightning striking other things in the immediate vicinity of the conductor is proportionately diminished2 the top of the rod is less likely to be fused when struck1 the stroke being divided between the various points2 and also because the brush discharge is thereby facilitated4 ,he dwells with much emphasis on the importance of the earth connection1 which he regards as a joint1 and advocates greater surface than is usual at present4 ,he illustrates an excellent deep earth connection formed by a galvanised cast-iron pipe1 #aj feet long and #a foot in diameter1 sunk in a well below the water level in the dryest season4 ,he insists that both deep and shallow surface earths are required4 ,lastly he insists on periodical inspection1 and the careful application of electrical tests4 ,in an appendix he describes his own testing arrangements1 with the results of nearly #ejj tests made by him for the ,war ,department1 from which he concludes 8that with the lightning conductors erected as they are at present by the ,war ,department1 electrical testing is of small value40 ,nevertheless1 in spite of this strong condemnation he asserts that the conductors now existing on our magazines and fortifications have never yet failed4 ,,specification 7,no4 #cibe4 ,september1 #ahhj7 of ,,samuel ,,vyle4 ,,lightning ,,conductors4 7,abstracted by ,g4 ,j4 ,symons1 ,f4,r4,s47 ,the invention may be divided into two parts4 ,in the first place1 the inventor proposes that in lieu1 for instance1 of the central strand of a seven-strand copper wire rope1 there shall be a central wire insulated from the others1 and only connected to them at the junction with the upper terminal1 while at the bottom this insulated wire is led up from the earth to some place where it is easy of access4 ,secondly1 there is a differential galvanometer1 resistance coil1 and other apparatus1 which being connected with the conductor and with the insulated wire1 will enable the efficacy of the conductor to be read off at any time4 ,,on ,,the ,,partial ,,protection ,,of ,,buildings4 7,by ,prof4 ,t4 ,hayter ,lewis1 ,f4,s4,a47 ,the following are suggestions whereby the ordinary materials used in building may1 to some extent1 be utilised as protectors against lightning3-- 7#a7 ,when the roofs and sides of a building are covered with galvanized sheet iron on a framework of wood1 if these coverings have good earth contacts1 either by themselves or through the ordinary iron rain-water pipe1 the building may be considered safe4 7#b7 ,cottages and small houses have usually iron eaves gutters1 slate or tile hips and ridges1 cement flashings1 and iron rain-water pipes4 ,if the joints be sound1 and the earth at the foot of the rain-water pipes be moist1 the houses will1 to a considerable extent1 be protected from the level of the eaves gutters downwards4 ,but as they will be quite unprotected about that level1 a wire rope or metal tape from the top of the highest chimney to the gutters1 which will very much diminish the risk1 is desirable4 7#c7 ,in larger buildings the gutters1 rain-water pipes1 hips1 ridges1 and flashings of the roof are often made of lead4 ,if the pipes have good earth contacts1 and conductors be fixed from the chimneys or other projections to the lead-work1 the buildings will be to some extent protected4 7#d7 ,when the hips and ridges of roofs are of slate1 terra cotta1 or other non-conducting materials1 conductors along the ridges1 connected with the rain-water pipes1 and with points along the ridge1 and to the chimneys1 will be required4 99 99 99 99 99 ,but all the buildings above described would be exposed to the risk of imperfect joints1 bad workmanship1 c42 so that no structure can be considered as secure unless it be protected by one or more conductors of approved size and metal1 and with carefully constructed connections and earth contacts4 ,,index ,,to ,,the ,,appendices4 ,,note4--,it must be distinctly understood that no responsibility for the statements or views indicated by this index or set forth in the appendices is assumed either by the delegates collectively or by the ,editor4 ,abel1 ,prof41 on ,mr4 ,preece's ,paper1 #ajb ,academy of ,sciences1 ,report made to1 #ea et seq4 ,accident at ,athelney1 ,bournemouth1 #bja at ,carmarthen1 #bag at ,caterham1 #baj ,masulipatam1 #bjf ,trolley ,bottom1 ,herts1 #aif in ,belgium1 #abi in ,england1 #ch1 #abi in low-lying parts of ,france1 #abi in mountainous parts of ,france1 #abi to a ,french frigate1 #bjj various1 #abf within small areas1 #bja ,action1 ,mechanical1 of lightning1 #he ,adams1 ,prof4 ,w4 ,g41 ,abstracts by1 #gf1 #hb ,addiscombe1 chimney of house struck1 #ch 8tna10 ,ship1 struck at ,corfu1 #hh ,aigrettes or brushes of points1 #aci 7,see ,,points ,,multiple74 ,air in electric field in state of strain1 #ace terminals 7,see ,,points74 ,alatri1 ,cathedral of1 #abf ,allen1 ,r41 ,letter from1 #ahc ,all ,saints' ,church1 ,nottingham1 struck1 #cg ,alphand1 ,m41 his ,report1 #fg ,alphington ,church1 near ,exeter1 struck1 #cg ,america1 gutters and water pipes used1 #abe ,analysis of ,manufacturers' ,remarks1 c41 #ag ,anderson1 ,r41 on ,lightning ,conductors1 #abj on testing1 #aaa1 #abg ,androut1 ,m41 his assistance1 #bbe ,angle iron conductors1 advantages of1 #aaa ,angles1 ,sharp1 to be avoided1 #aa1 #af1 #bh1 #ga1 #id1 #ii1 #agh useful for discharging electricity1 #aaa ,arago1 on bends in conductors1 #id earth terminals1 #ie ,architects1 ,royal ,institute of ,british1 ,report of1 #bg ,area protected 7,see ,,protection1 ,,area ,,of74 ,sectional1 #ae1 #ah1 #bb1 #di1 #aaj1 #aca1 #acb1 #aie1 #bbc insufficiency of1 #fc varied with length1 #g1 #i1 #ab1 #ac1 #ad1 #ai1 #bj1 #bd1 #aca not varied with length1 #d1 #af1 #bdc ,asted1 ,col41 ,report of ,accident1 #bjf ,atmospheric ,electricity1 #aab1 #aai by ,d4 ,brooks1 #aag by ,r4 ,phillips1 #ih origin of1 #aag ,attachment should always be of same metal as conductor1 #ba to building1 #g1 #h1 #i1 #aa1 #ac1 #ad1 #af1 #ba1 #bd1 #ca1 #ci1 #ha1 #ii1 #ajc1 #aae1 #abe1 #acj1 #aic ,attraction1 ,conductors do not attract lightning1 #ga ,specific1 equal in all bodies1 #gc ,attractive points1 #abg ,austria1 ,accidents in1 from ,lightning1 #abf ,aylmer1 ,j41 his assistance1 #bbh ,ayrton1 ,prof41 ,abstracts by1 #dc1 #hc1 #he1 #ij on ,clerk ,maxwell's ,lightning ,conductors1 #acb on ,indian telegraphs1 #ajb ,babinet1 ,m41 his ,report1 #fj1 #ff ,backstroke of lightning dangerous1 #he ,baker1 ,a4 ,j41 his ,report1 #cd ,ball1 ,hollow1 with small points 7,see ,,points ,,multiple7 #ac1 #bc is a point when compared to a cloud1 #gc lightning1 7,see ,,lightning ,,ball47 ,ballu1 ,m41 his ,report1 #fg ,band 7,see ,,tape and ,,plait74 ,barns full of new hay likely to be struck1 #abe ,barque 8,southern ,queen0 struck1 #bje ,bar of iron1 bad joints in1 #aaf ,melted by lightning1 #fa ,rectangular flat1 #gd ,small1 become heated1 #aaf ,base of conductor should bifurcate1 #fe1 #bdc ,batteries1 ,casemated1 #gj ,bayonne1 ,powder magazine at1 #hg 8,beagle10 ,h4,m4,s41 struck by lightning1 #aie ,beams1 how connected1 #aj ,becquerel1 ,m41 his ,report1 #fj1 #ff on discharge of lightning1 #aca on conducting power of metals1 #abd ,belgrand1 ,m41 his ,report1 #fg ,bell1 ,hornsby ,co4's experience1 #aic ,bells in church steeple1 #he ,bell wire acts as a conductor1 #ci1 #aie ,bends1 ,sharp1 to be avoided 7,see ,,angles74 ,berehaven lighthouse struck by lightning1 #bjh ,bisby1 ,mr41 of ,leeds1 his conductor1 #ge ,bishop's ,rock ,lighthouse1 #aij ,blitzableiter1 ,von ,g4 ,karsten1 #aad ,blunt conductor 7,see ,,ball and ,,points74 ,boat1 ,packet1 struck 7,see ,,ships7 #fa ,bolts1 ,iron1 attracted lightning1 #dj to be connected with conductor1 #aa ,books on ,lightning ,conductors1 ,catalogue of1 #adc ,bootham ,bar1 ,york1 #bai ,borrel1 ,m41 his views1 #bbf ,boy on pony1 pony killed1 boy escaped1 #dh ,branches1 ,connecting1 #ahc ,brandon1 ,d41 his ,report1 #cd ,brass not a reliable metal1 #fb1 #abd1 #bbg wire rope used in ,bavaria1 #abd ,break in conductor not fatal1 #ec to be avoided1 #fc ,brescia powder magazine blown up1 #gf ,british ,association ,report1 #ahfj1 #df ,brixton ,church struck1 #hd ,broek1 ,r4 ,van der1 ,abstracts by1 #aad1 #aai1 #acg1 #ach1 #adj1 #ada ,brook1 ,conductor to be carried to it1 #ad ,brooks1 ,d4 #ajc1 #aha ,brough1 ,mr41 on ,lightning ,rods1 #ai1 #di1 #aha ,bruntcliffe1 ,yorkshire1 ,gunpowder store destroyed1 #gd1 #baf ,brussels1 ,town ,hall at1 ,lightning protector at1 #ach ,brydone1 ,mr41 ,report of an accident1 #he ,buchanan1 ,g41 on gas works chimney1 #hi ,bucknill1 ,capt41 on the protection of buildings1 #bdc ,building1 containing masses of metal1 #fa continually under attacks1 #abc injured1 though protected1 #bg1 #abh ,long1 to have several conductors1 #be1 #bjb ,metallic1 safe1 #gb protected by cage of wires1 #acb struck from1 #aehi to1 #ahgi1 #abf ,burges1 ,mr41 #aij ,cable conductors 7,see ,,rope74 ,cagniard de ,latour1 ,m41 his ,report on ,points1 #fj1 #ff ,calcutta1 ,report on conductors at1 #aag ,callaud1 ,a41 his ,treatise1 #ajc his grapnel in basket of coke1 #aca ,canton1 ,mr41 his experiments in ,london1 #hj ,capacity of conductors1 #abg ,caps1 ,cast-iron1 to chimneys1 #ajc ,carbon in well1 #ahj ,carmarthen1 ,accident at1 #bag ,casing of lead or wood for iron earth terminals1 #abe ,catalogue of works upon lightning conductors1 #adc ,caterham1 accident at1 #baj ,cathedral of ,alatri1 #abf ,cavendish1 ,hon4 ,h41 his ,report1 #gf1 #gi ,cemented water tank1 iron conductor in it1 #acj ,chain conductors melted1 #fa1 #fb though broken1 still useful1 #ed objectionable1 #i1 #fa1 #fb1 #hh1 #abc ,early use of1 as conductors1 #abb ,old iron1 for earth terminals1 #gd1 #bjd ,chapel1 ,rycroft1 struck1 #de1 #df ,chapman1 ,gen4 ,sir ,f4 ,e41 his ,report1 #gb ,charcoal for earth terminals1 #ab1 #af1 #eh1 #abe1 #abf ,charles1 ,m41 his ,report on ,instructions for erecting conductors1 #eg ,cheapness of galvanized iron1 #acb ,chimney1 ,accidents to1 soon after erection1 #aid ,granite1 in ,plymouth ,dockyard1 struck1 #gc ,metal ,caps to be joined to ,conductors1 #abe ,new1 contain much moisture1 #aid not struck that had conductors1 #aic of ,edinburgh ,gas-works1 #hi over1 #ij feet have conductors1 #aic rod to be on1 #ajj rope on1 liable to corrosion1 #abe ,shafts1 copper band round top of1 #i ,stacks are ,conductors1 #g struck1 #bg1 #bh1 #dj1 #de1 #aic1 #aid struck because of heated air1 #aac struck before completion1 #id struck that had no conductors1 #ch1 #aic very rarely struck at ,glasgow1 #aic with soot dangerous conductors1 #ajf ,zinc1 struck1 #cg ,church1 ,brixton1 struck1 #hd ,charles1 at ,plymouth1 #hf ,christ1 ,carmarthen1 #bag ,rosenberg1 in ,carinthia1 destroyed1 #agcj1 #abc ,st4 ,bride1 ,fleet ,street1 damaged1 #abf ,ste4 ,croix1 ,ixelles1 struck by lightning1 #adj ,st4 ,george1 ,leicester1 damage to #abf1 #bdj ,st4 ,giles1 ,cripplegate's truck1 #aif ,st4 ,mary1 ,genoa1 #abf ,southampton1 damage to1 #abf ,steeple at ,bodmin1 destruction of1 #bjb struck1 #bi1 #cg1 #ajf1 #abf1 #acg1 #aii struck near ,isleworth1 #aii tower1 with pinnacles1 #aj1 #bi1 #acg towers struck in past1 #djj years1 #bjb with lightning conductor1 #abh without lightning rods damaged1 #abf ,cinders with grating 7,see ,,earth ,,terminals74 ,circuit to be tested by galvanometer1 #acj1 #bdd ,cistern dangerous for base of conductor1 #fd ,claire-,deville1 ,m41 his ,report1 #fg ,clamps1 ,iron1 acted as conductors1 #dc ,clark1 ,j4 ,e41 ,accident at ,bootham ,bar1 ,york1 #bai ,latimer1 ,abstracts by1 #ajc1 #ajf ,clay1 ,conductor to be taken below surface of1 #ad ,clevedon ,church struck1 #abf ,clifton1 ,e4 ,n41 his ,report1 #da ,clips1 ,gun-metal1 #bd ,clouds are not perfect conductors1 #aja ,cluster of points 7,see ,,points ,,multiple74 ,coke1 broken1 better than charcoal1 #aaf prevents action of sulphur1 #abj round conductors1 #i1 #aaf1 #aah1 #abf1 #aca center7,see ,,earth ,,terminals74 ,cole ,brothers1 #aib ,colliery ,chimney near ,sunderland struck1 #aic ,workings1 ,lightning in1 #bcg ,colson1 ,j41 his ,report1 #bh1 #cd ,commission on damage by lightning1 #abg ,comparative resistance to fusion1 #ada rupture1 #ada ,conducting power depends on amount of copper in conductor1 #bjj of metals1 #gd1 #abd1 #aca1 #aci of wires1 #agg ,conduction1 is it a question of surface or of mass8 #ae1 #ah1 #di1 #acb ,conductive capacity deficient in trees1 #abg ,conductor at ends of buildings has radius of protection lessened1 #acd ,construction of1 #fc1 #ajg1 #agh1 #agi ,cost of1 for ,houses of ,parliament1 #bcad1 #abb damaged by holdfasts1 #aae1 #aic destroyed at ground line1 #aca partly destroyed1 yet useful1 #fb deteriorate1 #abg dimensions of 7,see ,,size ,,of74 do not attract lightning1 #hh ,conductor1 every1 should be complete in itself1 #bb ,examination of1 #i1 #gb1 #ajb1 #aaa1 #abd1 #abg1 #acj1 #aca1 #acb1 #agi1 #bdd ,expansion of1 #aa1 #gj1 #abe1 #abh1 #bbf ,first1 #aba in ,england1 #he1 #aba in ,europe1 #abb1 #abi for lighthouses1 #aie1 #aii for iron ships1 #abb1 #bjj for wooden ships1 ,snow ,harris's1 #aie1 #aii for steeples1 with horizontal bands1 #abe how to be connected with metal portions of buildings1 #fe1 #abe1 #abf1 #abh imperfect1 ,effect of1 #ba1 #bji in contact with metal in chimney1 #aaa influenced by new water and gas mains1 #abg influenced by trees1 #abg is it to be a rope1 rod1 tube1 or band81 #ah1 #acb1 #aie joints in 7,see ,,joints74 laid in underground water1 #abh led into cemented water tank1 #acj water butt1 #ajg ,main1 #ahc must protect ridge1 gable ends1 and eaves1 #aab not to be insulated 7,see ,,insulation74 not to rise less than1 #ae;ft4 above chimney1 #abb now same as ,franklin's1 #abd number necessary1 how determined1 #ea of copper1 #ajg1 #acj and zinc wire1 #bje tape1 #bjf rope1 #aif1 #bjc the best1 #abe of hollow tube1 #abb1 #aif of ,hotel de ,ville1 ,brussels1 #abf of iron1 #ee1 #ajg1 #abe1 #aca1 #aci1 #adj of large surface better than rod1 #aac of links of copper1 #bjb of numerous thin wires1 #aci of solid bolt1 #aif of zinc wire melted1 #ajg ,conductor on buildings1 to be linked together1 #bjd on churches at ,torquay defective1 #acj on ridge of roof1 #abe outside1 #fj1 #abf ,points of 7,see ,,points47 properly made1 and properly fixed1 insures safety1 #ab protects conical space 7,see ,,protection1 ,,area ,,of74 reached water without earth plate1 #abh ,ridge1 #fh1 #agg should extend above building1 #ajf1 #bjb should it present a large surface section8 7,see ,,area ,,sectional74 size of1 #aj1 #ab1 #ah1 #ai1 #bb1 #hf1 #aai1 #abe1 #abf1 #abi1 #aca1 #aib1 #aid1 #bjb1 #bad1 #bbc1 #bbe1 #bdc spirally coiled up1 #abh struck by lightning1 #abh supposed perfect1 proved defective1 #aca theory and action of1 #ajf to be close to wall of building1 #aa1 #ae1 #hf to be continuous1 #agi to be fixed by iron staples1 #abe to be1 #d inches from walls and roofs1 #aah to be inside1 #abf1 #bbe to be on side most exposed to weather1 #fj to be of metal of high conductivity1 #aca to be symmetrically arranged1 #aje to earth by shortest route1 #abf to gas and water mains 7,see ,,earth ,,terminals74 to ,middlesboro' ,hospital1 #bjd to rest in hooks1 #agi to ,st4 ,alphege ,church1 ,greenwich1 #bjf to ,st4 ,michael's ,church1 ,blackheath1 #bje ,cone of platinum 7,see ,,platinum74 ,conic ,terminals 7,see ,,points74 ,conference ,circulars by the ,lightning ,rod1 #c1 #age ,conic ,space1 protected 7,see ,,protection1 ,,area ,,of74 ,connection 7,see ,,earth ,,terminals1 and also ,,joints74 of metallic masses1 #i1 #aj1 #gf1 #gg1 #ahf not necessary1 #abf ,contact between iron and copper to be avoided1 #aaa ,continuity between point and earth contact1 #abi ,contraction to be provided for1 #gj1 #abe1 #abh ,copper and iron form best conductors1 #aai and iron soldered1 #ajg and zinc wire bad for conductors1 #bje ,australian1 #abd better than silver1 #aci conducting power of1 #ai1 #abd1 #aca1 #aci conductors1 #ah1 #gj1 #hf1 #aag1 #aai1 #abe1 #abf1 #acj conductor too small1 #abf earth plate in dry sand1 #abh is it alone to be used81 #ah less liable to oxidise1 #aca not to be in contact with galvanized iron1 #ajb nuts1 #aib or iron conductors1 #gj1 #aib plates1 bent1 #abe plate ending for conductors1 #abh plates to provide for expansion1 #abe points 7,see ,,points74 preferred to iron1 #aca purity of1 #ai1 #abd rarely used1 #abe tape recommended1 #bjf rod conductor1 #ahe1 #ahf1 #bjb rod1 in4 diam4 has never been fused1 #abe rod on ,eddystone ,lighthouse1 #ahd rope conductor carelessly fixed1 #aif rope conductor insulated1 #aid rope to be used1 #abe1aca of thick wires ,russian1 #abd ,spanish1 #abd tubing1 #gd1 #abb wire fused throughout its length1 #aie wires1 deterioration of1 #aad wire rope applied to ,st4 ,paul's ,cathedral1 #aca wire rope1 dimensions of1 #h1 #bbc ,corn stacks fired by lightning1 #ahg ,coronal to be placed on chimneys1 #acb ,corrosion of joints of rod1 #abf ,cotton ,mill1 ,explosion at1 #bci ,coulomb1 ,m41 his ,report1 #ea1 #ec ,couplings1 form of 7,see ,,joints74 ,coutt's ,brewery1 a rod at1 #hi ,cramps1 iron1 stones held by1 #bi ,cross1 ,metal1 #ec1 #he1 #bbg ,croxton ,park1 trees struck1 #dh ,cruickshank1 ,a41 his ,report1 #dd ,crutches on roof to carry rod1 #eb1 #bbg ,current1 what it is1 #ajj ,cutting and ,co41 their conductor coupling1 #baf ,cylinder in water 7,see ,,earth ,,terminals74 ,cylindrical rod or wire rope the best1 #acd ,d',alibard1 ,m41 his experiments at ,marly1 #hj ,damage to building by alteration of position of safe1 #abg ,d',amico1 ,sig41 #agi ,damp air1 a conductor1 #dh ,dampness of new chimneys cause of being struck1 #aid ,danger of explosion from use of gas pipes1 #bja ,davioud1 ,m41 his report1 #fg ,davis1 ,h4 ,d41 suggestion about gas pipes1 #bja ,jno4 ,son1 their answer1 #ad1 #ae1 #ag ,davy on conducting power of metals1 #abd ,deaths from lightning1 #ajj1 #abf ,de la ,place1 ,m41 his ,report to ,french ,academy1 #ea ,de la ,rive says blunt points or balls equally effective1 #ajf ,de la ,rue's 7,dr4 ,warren7 experiments1 #acc1 #ace ,delaval1 ,m41 his ,report1 #gf ,delieul1 ,messrs41 points made by1 #ff ,de ,lor1 ,m41 his experiments in ,paris1 #hj ,denmark1 lightning conductors in1 #agf ,desains1 ,m41 his ,report1 #fg ,de ,saussure's neighbours frightened at his conductors1 #abb ,de ,senarmont1 ,m41 his ,report on points1 #ff ,designs for protecting private houses1 #abe ,despretz1 ,m41 his ,report on points1 #ff ,destruction of conductors by use of iron wall eyes1 #aca ,dimensions of conductors 7,see ,,conductors1 ,,sizes ,,of74 ,dimensions of upper terminals1 #ag1 #ah ,discharge diverted from conductor by an anchor1 #abh from thunder cloud over plane surface would be vertical1 #abg of electricity by trees lessens energy of lightning1 #abg of electricity of high potential obeys laws of ,ohm1 #acd of lightning--,earth contact1 #aca passes through conductor1 ,faraday1 #acb ,discharging fork to be attached to lower end of conductor1 #aa1 #bca ,doherty1 ,j41 on explosion at ,swan ,cotton ,mill1 #bci ,doors1 copper1 to magazines1 #gd iron1 to powder store1 #gf lightning passed out of1 #bg1 #dh ,drain1 conductor to be led into1 #ad ,duc1 ,m41 his ,report1 #fg ,dugmore1 ,mr41 his evidence1 #aih ,duhamel1 ,m41 his ,report1 #fj1 #ff ,dulong1 ,m41 his joint instructions1 #ei ,dum ,dum1 accident at1 #aha ,du ,moncel1 ,comte1 #fg1 #bbf ,dungeness ,lighthouse1 #ahc1 #ahf ,duprez1 ,m41 his statistics of buildings and ships struck1 #ia on height of points1 #if ,dymond1 ,e4 ,e41 ,abstracts by1 #ea1 #ajh ,earth1 8bad01 #aaj1 #aag1 #abf1 #abg1 #bji1 #baj1 #bah moist1 better than a well for end of conductor1 #gd plate1 pipe1 or tube1 #i1 #bd1 #ajj1 #aad1 #aae1 #aah1 #abj1 #abh1 #agg1 #agi1 #ahf1 #bca plates at ,torquay carried out to sea1 #acj unnecessary1 #af ,terminals1 #aa1 #ac1 #ad1 #ae1 #ba1 #ef1 #ie1 #ajb1 #ajf1 #aji1 #aaf1 #abf1 #aca1 #adj1 #ahj at base of rain water pipe1 #acb bad1 #aaj1 #aag1 #abf1 #abg1 #bji1 #baj1 #bah ,borrell's1 #bbf ,callaud's1 #ajd1 #abe1 #aca destroyed in moist earth1 #aaf ,discussion on1 #aca ,duplicate1 #fe important1 #aa1 #ga1 #abf1 #aca1 #bdc ,earth ,terminals of conductors in iron box1 #abf1 #bca of conductors1 ,stotherd1 ,lt4-,col41 #acj in wells1 #ae1 #ef1 #fj1 #gd1 #gg1 #ajj1 #aah1 #abf1 #aci1 #agi1 #ahj1 #bca1 #bdc iron should be galvanised1 #abj length of1 #aa multiple1 #aci1 #bdc ,oxidation of1 #abe1 #aca ,rules for1 #fd1 #gb1 #acb to be accessible1 #fh to be carried away from building1 #ajg to be connected1 #abj to be deep and wet1 #ajg to be good1 #abf1 #acj to be in moist ground1 #ba1 #eb1 #ee1 #ef1 #eh1 #gd1 #aac1 #aah1 #abc1 #abd1 #abe1 #abf1 #aca to be tested1 #aaa1 #aca with charcoal cinders or coke1 #i1 #ab1 #af1 #bc1 #bd1 #eh1 #ajd1 #aaf1 #abj1 #abe1 #abf1 #aca with coil of conductor1 #i with galena1 c41 #eh with gas pipes 7,see ,,gas74 with iron forks or harrows1 #aa1 #aca with old iron1 #gd1 #bjd with water1 #eb1 #ec1 #fg1 #fh1 #abf1 #acj1 #adj pipes1 #i1 #bf1 #df1 #ee1 #ef1 #fh1 #aah1 #abe1 #abf1 #abg1 #abh1 #acb1 #bca1 #bce1 #bdc ,eddystone ,lighthouse1 #ahc1 #ahd1 #ahf1 #ahi1 #aia ,effects of climate on copper and zinc wire ropes1 #bje ,electric current checked1 #aic discharge takes path with best conduction1 #abg fire not diverted from its path by rod1 #abe ,electricity a terribly explosive power1 #gb ,atmospheric1 #ih1 #aab1 #aag1 #aai ,electricity1 frictional and atmospheric the same1 #hb1 #aab carried off by water pipe1 #abf for telegraphic purposes follows ,ohm's laws1 #acc is force1 not matter1 #ajj of earth negative--atmosphere positive1 #aab ,static1 laws of1 #acb will leave small conductors for large ones1 #bjd ,electrodes1 #aaj ,elevated rods preferable to low conductors1 #gi ,end of conductor1 lower1 to be coiled up1 #i ,energy of lightning lessened by trees1 #abg ,england1 accidents from lightning1 #abf ,escurial1 no conductor on1 #ajj ,examination of ,conductors 7,see ,,conductors1 ,,examination ,,of74 ,expansion of conductor to be allowed for1 #aa1 #gj1 #abe1 #abh1 #bbf1 #bbi ,experiment on wire across ,thames1 #aba on plait of copper and zinc wire at ,blackheath1 #bje with a very thin strip of tinfoil1 #aii with glass rods1 #aba ,explosion of a gas meter1 #bci ,explosions1 electrical1 their cause1 #ha ,extent of surface does not favour lightning discharges1 #acd ,eyes for fastening conductors1 #ii1 #aae 7,see ,,attachment74 ,faraday on conductors1 #hc1 #hd1 #hi1 #ajb1 #acb1 #ahc1 #ahf1 #ahg1 #ahi1 #aij1 #aie1 #aif1 #aii4 ,field1 ,rogers1 ,c4,e41 on accident at ,caterham1 #baj on ventilating pipes1 #baf ,fire of inflammable materials1 #abg ,first conductor erected in ,england1 #he1 #aba ,first conductor fixed in ,europe at ,hamburg1 #abb1 #abi ,fixing conductors to ships1 #hg ,fizeau1 ,m41 his report on powder magazines1 #ff1 #fg ,flagstaff should have a conductor1 #gj struck1 #dd1 #ahg1 #aif ,flashing1 ,lead1 how to connect wire rope with1 #aj1 #aa1 #cd ,flash1 lightning1 effects of1 #hd ,flow of electricity through conductors1 #acc ,flues copper1 #ahc1 #ahe lightning passed down1 #ch1 #ci warm1 and an iron grate1 a dangerous conductor1 #aja ,forest ,hill1 chimney of house struck1 #ch ,forms of upper terminals 7,see ,,point74 ,formula for determining area protected 7,see ,,protection1 ,,area ,,of74 ,foster1 ,prof4 ,g4 ,carey1 on ,personal safety1 #bcc ,fountains1 ,public1 conductor lead away from1 #ef ,franklin1 ,dr41 and wet rat1 #he discovered pointed metal best conductor1 #aba erected lightning rod to his house1 #aba experiments1 #gi1 #hd repeated by ,buffon ,dalibar1 #aae first conductor was melted1 #aaf his report to ,french ,academy1 #ea on cold fusion1 #ajb on connection of lightning rod1 #ed report on ,purfleet1 #gf1 #abf round rod best1 #aad success in pushing use of conductors1 #aba tried his kite successfully1 #aba ,freeman ,collier1 their answer1 #aj1 #ag ,french instructions1 #ea on area protected1 #bb ,fresnel1 ,m41 his instructions1 #ei ,frost1 ,a4 ,j41 ,abstracts by1 #ii1 #aah ,fusion1 metals which resist1 only to be used1 #aci of defective conductor1 #bae of rod1 ,wheatstone on1 #hc ,gable near conductor struck by lightning1 #bh ,galena1 and melted sulphur1 ,bed of for end of conductor1 #eh ,galvanic action between iron and copper1 #aaa1 #acj of wet and smoke on conductors1 #bje ,galvanised conductor painted1 #aci iron1 #ai1 #fg1 #fh1 #gb1 #aja1 #abj1 #abd1 #abe1 #acb1 #aci not to be in contact with copper1 #ajb ,galvanised iron best material for earth contact1 #acj ,galvanometer for testing earth currents1 #aca ,gas and water mains1 #aac utilisation of1 #i1 #bh1 #cg1 #ci1 #dd1 #gb1 #ajj1 #ajb1 #ajc1 #ajh1 #aad1 #aag1 #abe1 #abf1 #abh1 #ach1 #bja1 #bca1 #bce ,gas coke for earth terminal1 #bc1 #bd ,gases from chimney injure conductors1 #aaa ,gas ignited1 #bai meter exploded1 #bci ,gasometer struck1 #dc ,gas-pipes1 ,soft metal1 not to be used as conductors1 #ajh ,gavarret's1 ,m41 experiments1 #aci ,gavey1 ,j41 on accident at ,carmarthen1 #bag ,gay ,lussac's iron conductor recommended1 #ajd ,german 8reception rod0 of iron1 #abe ,geneva cathedral1 #ajc ,genoa1 ,st4 ,mary's ,church1 #abf ,gilbert1 ,dr4 7#afjj7 magnetic and galvanic action one force1 #abj ,gilt point 7,see ,,point ,,gilded47 ,girard1 ,m41 his instructions1 #ei ,girders1 how connected1 #aj ,glass1 foundation of house insulated1 #aah insulators 7,see ,,insulators47 repeller1 #hc1 #ahe1 #ahf ,globular ,lightning 7,see ,,lightning1 ,,ball74 ,goldie's1 ,mr41 experience1 #aic ,governments1 ,french and ,english1 size of rod sanctioned by1 #ab ,grapnels and gratings for earth plates1 #abe1 #abf1 #aca ,gray1 ,j4 ,w4 and ,son1 their answer1 #g-i1 #ag 8,gridiron10 ,termini of ribs pointed1 #bc1 #bd ,groome's1 ,j4 ,e41 evidence1 #aif1 #aig1 #aih ,ground connection 7,see ,,earth ,,terminals74 containing ironstone1 #dh ,guillemin's1 ,m41 opinion1 #acb ,gunpowder stores1 conductor1 how to be fixed1 #hb ,gutters1 ,metallic1 #dj1 #da1 #de1 #df1 #dg1 #fj1 #abe1 #bac must be connected with conductor1 #fj utilization of1 #dg1 #abe1 #bdd ,guyton1 ,m41 his practice with charcoal1 #eh ,haigh ,son's ,colliery1 #gd1 #baf ,harris1 ,sir ,william ,snow1 ,crown adviser1 #h combated the idea that rods attracted lightning1 #abb conductors to ships and buildings1 #hc1 #abb1 #acj1 #aif in conflict with ,faraday1 #aie1 #aif1 #bjj on ,sectional ,area1 #aaj on copper conductors1 #bjb on expense of conductors1 #di on fusion1 #hf on hollow or solid conductors1 #gd on relative conductivity of metals1 #ga on shipwrecks by lightning1 #ij on thunderstorms1 #he ,principles adopted by1 #gj1 #aja regarding insulators1 #ae report on safety of conductors1 #gb1 #aaj says discharges pass over surface1 #acb suggestions issued in army circulars1 #abb ,hauksbee1 ,f41 ,f4,r4,s41 similarity of electric flash and lightning1 #aba ,hawksley1 ,t41 his report1 #cg ,hay a bad conductor1 #abg ,hay newly gathered1 inflammable1 #abg ,heated smoke from chimney1 a conductor1 #acb ,heckingham poorhouse struck1 #hg ,height of rods1 #abj1 #abd1 #abe1 #aci1 #agg ,hemispheres of brass1 experiments with1 #aje ,henly1 ,w41 his report1 #gh1 #gi ,henry1 ,prof4 ,joseph1 on construction of lightning rods1 #ii1 #aha ,herring's1 ,mr41 evidence1 #aif ,heryet1 ,chas4 ,j41 his opinion1 #bjf ,higginbotham's1 ,mr41 evidence1 #aid ,high buildings a source of safety to lower ones near1 #ab ,highton1 ,e41 on lightning conductors1 #bci ,hill1 ,a41 his ,report1 #cg ,hine1 ,g4 ,j41 his ,report1 #cg ,hine1 ,t4 ,c41 and ,sons1 ,architects1 ground plan of ,nottingham ,castle1 #bf ,holborn ,union ,infirmary1 ,upper ,holloway1 struck1 #ci ,holdfast1 brass1 #af copper1 #g1 #h1 #ac1 #af1 #ba1 #bd1 #ci driven in too tight1 #af1 #aic 7,see ,,attachment47 ,hole in ship's side1 made by lightning1 #fb ,honeyman's1 ,j41 evidence1 #aid ,hook and rings used as joints1 #id ,hoop iron in brickwork of chimneys struck1 #df ,hoops round chimney1 #hi ,hopkins1 ,rev4 ,g4 ,h41 his ,report1 #cj ,horizontal conductor1 #ga conductors for steeples1 #abe ,horsley1 ,bishop1 his ,report1 #gi ,hotel des ,invalides1 ,paris1 conductor on1 #hf ,hotel de ,ville1 ,brussels1 conductors of1 #abf ,house at ,bethnal ,green cut in two by lightning1 #da at ,bournemouth with1 #g conductors1 #aii at ,cannes 7,france7 struck1 #aih near trees struck1 #abg of ,parliament protected by ,harris's conductors1 #abb with two separate conductors1 #abh ,hugueny1 ,m4 ,f41 on 8,le coup de foudre de l'ile du ,rhin01 #ii ,ignition depends on retardation of discharge1 #abg ,infirmary1 how to be protected1 #aj ,ingenhousz's1 ,dr41 experiments1 #abb ,ingram1 ,mr41 of ,belvoir ,castle1 on trees struck1 #dg ,inspection of conductors1 #i1 #gb1 #ajb1 #aaa1 #abd1 #abg1 #acj1 #aca1 #acb1 #agi1 #bdd ,instructions1 #fc1 #ii1 #agf1 #aha1 #bdj ,british ,army ,circular1 #gj ,french ,official1 #ei for formation of good earth1 #fd1 #gb1 #acb ,instrument hut at ,valencia1 how protected1 #aje ,insulation1 shock decreased by1 #aah ,insulators1 #cd1 #cg1 #gf1 #ii1 #ahd1 #ahf1 #aid approved1 #ac1 #aah objected to1 #h1 #aa1 #ac1 #ad1 #af1 #ba1 #bd1 #fh1 #fi1 #gc1 #hf1 #hi1 #ajc1 #aaa1 #aah1 #abf1 #aci1 #ahf1 #bbf ,iron a better conductor than formerly1 #ai and copper form best conductors1 #aai as a conductor1 not objected to if galvanised1 #ai bar1 #aca1 #bbf melted1 #fa bars on ridge for metallic connection1 #abe better than copper1 #aib1 #bdc box for earth contact of conductors1 #abf ,iron buildings covered with asphalte1 #gj built ship1 metal-rigged1 if protected1 #abb1 #bjj cables1 galvanized1 sometimes used1 #abe conductors1 #ah1 #fi1 #gd1 #aaf1 #abe bad1 #i1 #ci1 #aib good1 #ha1 #bdc cost of1 #ai1 #gj1 #abd1 #acb should weigh1 #ac to1 #cg oz4 per foot1 #aai galvanized for conductor1 #gd1 #aaf1 #acb1 #aci has greater specific heat than copper1 #acb its high temperature at fusion1 #acb in coke undergoes no change1 #aaf ,joints in defective1 #aaf not to be used for rods1 #abc points1 #hh1 #ach pumps reaching to water act as attractive points1 #abg rain water pipes1 good conductors1 #ajb1 #aac 8reception rod0 used in ,germany1 #abe rods on all sides best protection1 #abd safe in altered position caused damage to building1 #abg staples and wall eyes1 #abe1 #acj terminal rods1 #abd1 #abe underground1 destruction of prevented1 #abe wires surrounding copper wire1 #bjj ,isolators 7,see ,,insulators74 ,italy1 ,lightning rods used there1 #agi ,jarriant1 ,m41 his books abstracted1 #aaa1 #aae his manufactory1 #bbg ,jenkin1 ,professor1 says point prevents discharge1 #ajf ,jerman1 ,j41 his report1 #cg ,johnson1 ,clapham ,morris1 their answer1#ac ,johnston1 ,w4 ,p41 #aha ,joints1 avoided in wire cables1 #acb ,cutting ,co41 #baf damaged1 #fi1 #aaj1 #abf how avoided in upper terminals1 #bc how made1 #g1 #i1 #aj1 #aa1 #ac1 #ad1 #af1 #bj1 #bd1 #eb1 #ee1 #ei1 #fc1 #gj1 #ga1 #ajc1 #agi1 #aib1 #bdc must be perfect1 #eh1 #aca of bars always defective1 #aaf of extra thickness1 #gd of rain water pipes1 #acb ,joints should be metallically continuous1 #bj soldered1 #i1 #bd1 #ff1 #fh1 #gj1 #ga1 #ajb1 #abc1 #abe1 #aci1 #adj1 #ada1 #bdc to be avoided1 #aj1 #aa1 #af1 #bj1 #fc ,journal of ,society of ,telegraph ,engineers1 ,may1 #ab1 #ahge1 #acj 8,jupiter0 ship struck1 #fb1 #ie ,karsten1 ,prof4 ,d4 ,g41 lightning conductors1 by1 #aai ,kew1 experiments at1 on atmospheric electricity1 #aab ,kilbourne1 ,lieut41 #aha ,kirchoff1 ,prof41 on connection with gas mains1 #bce ,kite1 ,silk1 ,franklin's experiments with1 #hj ,korte's1 ,messrs41 ,paper1 #aje ,lacoine1 ,m41 on area protected1 #acd ,lane1 ,t41 his ,report1 #gi ,lantern on lighthouse1 #ahd1 #ahf ,la ,place1 ,m41 his ,reports1 #ec1 #eg ,lateral discharge1 #gc1 #hc1 #hd1 #he ,latham1 ,baldwin1 on conductors1 #bjb ,law1 ,e4 ,j41 his ,report1 #cg ,laws of ,static electricity1 #acb ,lead a bad conductor1 #abc at joints1 #id1 #abe casing for upper terminals1 #aca floors1 #ahh1 #ahi liked because of fitting sharp curves1 #abc pipe for earth connection1 #gg roofs and spouts1 #ea1 #hb1 #ajb thin sheet of1 covering ends of wire1 very dangerous1 #bj ,leaves of trees draw off electricity1 #hd ,lefevre-,gineau1 ,m41 his instructions1 #ei ,le ,gentil1 ,m41 his observations1 #hd ,length and sectional areas1 proportion between1 #ad of conductor above top holdfast destroyed1 #aic of conductor determines amount of resistance1 #aca ,lenz1 ,m41 on conducting power of metals1 #abd ,leroy1 ,m41 his ,report1 #ea1 #ec ,lewis1 ,prof4 ,t4 ,hayter1 ,abstracts by1 #gj1 #gi1 #ha1 #hd1 #ajj1 #aaj1 #aab1 #aag1 #abj1 #agi his joint ,report1 #bh1 #cg ,leyden discharges and lightning flashes1 #hd ,jar1 #aba ,lichtenberg of ,gottingen1 his opinion1 #abi ,liddell1 ,j41 on lightning conductors1 #bjb ,lighthouses and exposed buildings protected did not suffer1 #ajf ,lighthouse at ,berehaven struck by lightning1 #bjh damaged by lightning1 #aif lightning rods on1 #ahc1 #aij ,lightning an immense electric spark1 #abc ,ball1 #ii1 #aja1 #ajb1 #ajh1 #bje1 #bdb ,bifurcated1 #de conductor 7,see ,,conductor74 diffused1 #ajh does it pass inside or outside conductor81 #ae1 #ah1 #di1 #acb ,flash1 #ajh follows line of least resistance1 #ajh ,force of1 exemplified1 #de ,globular 7,see supra ,,ball74 going to earth without conductor1 #abh identical with electricity1 #hb incandescent matter1 #ajj in colliery workings1 #bcg leaves conductor and enters chimney1 #bjc passed down mainmast and through ship1 #aie passed to iron supports1 #abh passing out of a ship by a copper bolt1 #bje ,personal safety from1 #bcc protectors 7,see ,,conductors74 ran along a bell wire1 #aie thatched roof of house1 #abh ,rod ,conference1 their ,circular1 #bh ,rods 7,see ,,conductors74 ,sheet1 #ajh the cause of1 #ha various forms of1 #ajh ,lime1 to prevent oxidation of cylinder1 #adj ,line1 conductor should run round building1 #acd ,linked system of conductors introduced by ,sir ,w4 ,s4 ,harris1 #bjd ,links of chains1 #agi ,llandaff ,cathedral1 conductor on1 #ajb ,lofty buildings require larger rods 7,see ,,area1 ,,sectional74 ,long conductors above buildings1 their effect1 #gg ,long's1 ,f41 account of injury to ,wells ,church1 #aie ,louvre1 ,new ,buildings of the1 ,special ,report for1 #fd slightly injured by lightning1 #abc ,low straggling buildings should have several conductors1 #ae ,lucas1 ,mr41 his ,report1 #fg ,lussac1 ,gay1 ,m41 his ,report1 #eg1 #ei ,mc,donald's1 ,mr41 experience1 #aic ,mc,gregor1 ,w41 protection from ,lightning1 #ajf ,magazine1 copper doors and windows to1 #gd1 #baf of metal1 the safest1 #gc underground1 #gj well at each end of1 #abf 7,see also ,,powder ,,magazines74 ,magne1 ,mr41 his ,report1 #fg ,mahon1 ,lord1 his ,report1 #gi ,mairie1 of1 #bjth ,arrondissement struck1 #fi ,majendie1 ,major ,v4 ,d41 his ,report1 #gd1 #baf ,malcolm1 ,major1 ,r4 ,e41 discussion on lightning conductors1 #aca ,mann1 ,dr4 ,r4 ,j41 ,lecture at ,society of ,arts1 #ajh discussion on earth connections1 #aca discussion on lightning conductors1 #aca ,man might touch conductor in thunder storm1 #abf ,marseilles1 ,powder ,magazine at1 how to be protected1 #ea1 #eb ,massingham1 ,t41 evidence and letter1 #ae1 #af1 #ag1 #aic ,masses1 metallic must be connected with conductor1 #fj1 #id1 #ajd1 #abf1 #acb1 #bdj ,mass or surface1 which conducts81 #ac1 #ae1 #ah1 #di1 #gd1 #acb1 #bbg ,masts of large vessels1 each to have a conductor1 #f ,masulipatam1 accident near1 #bjf ,materials1 inflammable1 not ignited1 #abg ,maxwell1 ,hugh1 on kind of trees struck1 #dg ,maxwell's1 ,clerk1 ,theory1 #aji1 #abf1 #acb1 #acc ,mechanical action of lightning1 #he ,meiszner's improvement1 #acj ,melsens says discharge passes over surface1 #acb ,system of protection as applied to monument at ,lacken1 #bcj various works by1 #abd1 #ach1 #adj1 #ada ,men-of-war1 old conductors in1 #bjb ,merton ,college1 ,oxford1 damaged1 #abf ,metallic cap may assist protection of house1 #acb circuit1 #abf connection must be perfect1 #acj connections on ridge by iron bars1 #abe joints1 #hi ,metals1 contact of dissimilar1 results in decay1 #ai1 #ba ,metal cowl of chimney struck1 #aih for points must be good conductor1 #aci immaterial if sectional area be large1 #aca in buildings1 contiguity with to be avoided1 #e inside or out1 to be connected with conductor1 #abe1 #abf melted1 dimensions of1 #fa1 #hc1 #bbc1 #bca of high conductivity for conductors1 #aca stays and fastenings1 #ahd1 #ahe ,michel1 ,m41 ,papers by1 #fg1 #fh1 #aaa1 #aca on galvanised wire rope1 #aca ,milne1 ,d41 his ,report1 #dd ,mining ,engineers1 ,enquiry by1 #bcg ,mohn's1 ,h41 ,lynildens ,farlighed ,i ,norge1 #ajf ,moist earth destroys terminal1 #aaf for lower terminal1 essential1 #ba1 #eb1 #ef1 #eh1 #abe1 #abf center7,see ,,earth ,,terminals74 ,moisture1 ,access of1 to surfaces in contact1 #ga ,moncel1 ,comte du1 his ,report1 #fg his opinions1 #bbf ,monte ,video1 ,english ,consul's house struck1 #aie ,montgolfier1 ,m41 his ,report1 #eg ,monument1 ,london1 its immunity from injury by lightning1 #ajc ,morea1 ,signor ,lerigi1 #ahj ,mller's1 ,prof41 conditions for lightning conductors1 #abi ,mller's1 ,dr4 ,hugo1 experiments1 #ace ,municipal buildings in ,paris1 lightning rods for1 #fg1 #bbe ,munson1 ,d41 ,co41 their rods1 #baf ,murgatroyd1 ,j41 his report1 #ci ,murray1 ,j41 on ,atmospheric ,electricity1 #hb ,musgrave1 ,dr41 his report1 #gi ,myers1 ,gen41 #aha ,nails1 copper1 used in attaching conductor to building1 #ad center7,see also ,,attachment74 ,nairne1 ,e41 his report1 #gi ,nash lights1 #ahc1 #ahg ,national ,institute 7of ,france7 report made to1 #ec ,nelson column1 #ij ,newton1 ,sir ,i41 machine of glass1 #abj 8,new ,york10 packet boat1 struck1 #fa1 #fb ,nickson1 ,mr41 his report1 #gh ,nottingham1 ,castle1 how protected1 #bc1 #bd ,nuts1 copper1 #aib center7,see ,,joints74 ,number of persons killed by one discharge1 #abi ,objects on plains attract lightning1 #abg ,odour1 sulphurous1 of lightning1 #he ,official instructions3 ,denmark1 #agf ,england1 #gj-gd ,france1 #ea-fi ,india1 #aha ,italy1 #agi ,norway1 #ajf1 #agf ,united ,states1 #aha ,ohm1 his laws1 #ah1 #acc on conducting power of metals1 #abd ,oldham1 ,explosion at1 #bci ,oliver1 ,t41 his report1 #ci ,oxidation1 how to be avoided1 #hc of copper less than that of iron1 #aca of cylinder1 #adj earth terminals1 #aca surface of conductor unimportant1 #gc terminals leads to failures of conductors1 #aca ,painted conductor1 #fi1 #id1 #ii1 #ajc1 #aac1 #aag galvanized conductor1 #aci ,paint objected to1 #fg1 #bbg ,palais de l',industrie1 ,paris1 its construction1 #fa ,paratonnerres1 ,trait des1 #ajc ,a ,collin et ,fils1 ,paris1 #aag ,nouveau par ,jarriant1 #aaa par ,jarriant1 #aae ,partial protection1 #aid1 #bdd ,passage of electricity of tension in bad conductors1 #ada ,patterson1 ,mr41 of ,philadelphia1 on good contact1 #eh ,payneshill1 site of first conductor1 #he ,pearson1 ,j4 ,l41 his report1 #ci ,pegwell ,bay1 tide receded1 #dh ,pennycook ,co41 their answer1 #ac1 #ad1 #ag ,perfect lightning conductor1 #aca1 #ahf ,perforated iron pipe as earth terminal1 #aad ,perrott's1 ,m41 experiments1 #aci remarks on earth contacts1 #adj ,perry1 ,prof41 on conductors1 #acb ,personal safety from ,lightning1 #bcc ,persons killed by lightning in ,france1 #abi ,perspiration from flock of sheep1 a conductor1 #dh ,phillips1 ,r41 on atmospherical electricity1 #ih ,phin1 ,john1 on lightning rods1 #ajb1 #aha ,phipson1 ,r4,m41 account of destruction of ,wells ,church1 #aid ,pidgeon1 ,mr41 discussion on earth connections1 #aca ,pierron1 ,m41 his proposal1 #eb ,pinnacles on church towers1 #aj1 #bi1 #acg ,pipes1 gas1 7,see ,,gas1 ,,water1 and ,,earth ,,terminals74 hard metal1 as conductors1 #ajh iron1 easily made into protectors1 #ajb of terra cotta1 #ahj rain-water1 #cd1 #gd as earth terminal1 #aad ,plait of copper wire1 #e1 #i1 #bje1 #baj1 #bae ,planta1 ,mr41 his report1 #gi ,plate1 ,earth 7,see ,,earth ,,plate74 ,platinum points1 #cg1 #aae1 #adj1 #bbg approved of1 #ae1 #ed1 #ee1 #ei1 #fc1 #ff1 #ii1 #ajd1 #aaf1 #abj objected to1 #fg1 #gc1 #ajc1 #abc1 #aci only half the conducting power of copper1 #gc blunted1 #fi fused1 #abh1 #bca ,plymouth1 ,charles ,church at1 #hf ,point ,aigrettes 7,see infra ,,multiple74 attracts electricity1 #hb blunted1 #ec1 #fi breaks the force of lightning1 #gc coronal 7,see infra ,,multiple74 dimensions of1 #ag1 #ah1 #abj1 #acj1 #agh ,duhamel upon1 #ff ,engravings of some modern ones1 #bcj facilitate discharge1 #aca ,point generally1 #i1 #ag1 #ah1 #gf1 #gi1 #ha1 #hf1 #ib1 #abb1 #abe1 #aca1 #aci gilded1 #i1 #ee1 #ei1 #ga1 #abj1 #ach needless1 #gc1 #ajc1 #aac height of1 #eb1 #ach how to be fixed1 #ad1 #eb1 #ec1 #ee1 #eh1 #acj in situ1 examination of necessary1 #ah melted1 #ec1 #hg1 #ib1 #aib1 #aie1 #bca multiple1 #cd1 #bca recommended1 #aj1 #ac1 #ad1 #ae1 #bc1 #ajd1 #ajh1 #abe1 #acb1 #aci1 #bdc objected to1 #ah1 #ga not to be fusible1 #ic1 #abj of attraction1 #abg copper1 #aj1 #ac1 #bc1 #ff1 #fg1 #ajg1 #aaa1 #aag1 #abj1 #abc1 #acb1 #aci iron1 #hh1 #ach brass1 #ac pinnacles to be united to main conductors1 #aah platinum 7,see ,,platinum74 silver1 #g1 #abj1 #acj1 #aci three kinds1 #ach vane1 #ahf center7,see ,,vanes74 or blunt conductors1 #gg1 #gi1 #ajf render lateral discharges less probable1 #aca ,report upon1 #fj1 #ff sharp1 #abi1 #acj1 #acb1 #ach1 #aci not too1 #ib1 #abc1 #abi1 #bdb experiments with1 #ea1 #hj should be kept clean1 #acj1 #acb of good conducting metal1 #aci should it be painted8 7,see ,,painted74 space protected by 7,see ,,protection1 ,,area ,,of74 square tapering1 #bc used in ,germany1 fire gilded copper cone or sphere1 #aje1 #aaa1 #acj useful1 #ajb1 #abb useless1 #gg1 #ajc1 #aac vertical1 horizontal1 or perpendicular1 #eh ,poisson1 ,m41 his joint instructions1 #ei ,polarity of ship's compass reversed by lightning1 #aba ,poles1 ,telegraphic1 how protected1 #aja ,pouillet1 ,m41 his joint ,report1 #fj1 #ff on ,conducting ,powers of ,metals1 #abd ,discharge of ,lightning1 #aca ,powder magazines1 #ea1 #eb1 #ee1 #ef1 #eg1 #ff1 #fg1 #gj1 #gc1 #gd1 #gf1 #ha1 #hg1 #aji1 #aah1 #abc1 #abf1 #acj1 #agg1 #agh1 #baf ,preece's1 ,mr4 ,w4 ,h41 ,abstract of ,replies of ,manufacturers1 #bb ,discussion on ,lightning ,conductors1 #aca ,discussion on ,earth ,connection1 #aca ,abstracts by1 #ih1 #ajb1 #aag1 #acj1 #acb1 #bda1 #bdc on ,conductors1 #ajj ,ball ,lightning1 #aja1 #ajb ,paper ,discussion on1 #ajb ,proper ,form of ,lightning ,conductors1 #acb ,space protected1 #ace ,priestly1 ,dr41 his ,report1 #gi ,pringle1 ,sir ,john1 his ,report1 #gi advocated use of points1 #abb ,protector 7,see ,,conductor74 ,protection1 ,area of1 #f1 #i1 #ac1 #ae1 #af1 #ba1 #bb1 #bd1 #eg1 #fj1 #fd1 #fg1 #ga1 #gc1 #hb1 #hg1 #if1 #ajb1 #ajf1 #aaa1 #aab1 #aag1 #abc1 #abe1 #acd1 #ace1 #acg1 #ahj1 #aib1 #bbf1 #bcj1 #bdc of buildings from lightning1 #aie buildings from lightning1 ,r4 ,s4 ,brough1 #acb iron from decay by galvanizing1 #acb telegraph wires by lightning conductor1 #acj partial1 #aid1 #bdd ,prussia1 accidents from lightning1 #abf ,purfleet1 ,board ,house struck1 #gf1 #gh1 #hh1 #abb1 #abf ,purity of copper essential1 #abd ,quadrangular iron bar for conductor 7,see ,,iron1 ,,bar ,,of74 ,questions respecting damage by lightning1 #bh1 #bi ,radius of ,protection 7,see ,,protection1 ,,area ,,of74 ,railings to be joined to conductor1 #abe ,railway ,terminus at ,antwerp struck1 #acg track makes capital earth1 #aag ,rain-water pipe as conductor1 #cg1 #ch1 #da1 #acb1 #bac ,rat1 ,wet1 indestructible by electricity1 #he ,ravel1 ,m4 de ,puy ,contal1 his proposal1 #eb 8,reception rod0 of iron used in ,germany1 #abe ,regnault1 ,m41 his reports1 #ff ,regnier's system of lightning rods1 #ed1 #eg ,regulations for lightning conductors in ,denmark1 #agf ,repellers1 ,glass1 #ahf ,resistance of conductor varies with its length 7,see ,,area1 ,,sectional74 ,retarding influence of electrostatic capacity1 #acc ,return shock mechanical in effect1 #abi ,ribbons and tubes still in use1 #acc or rods offer less resistance than ropes1 #bjd center7,see also ,,tape47 ,richard ,co41 their tall chimney struck1 #dd ,richmann1 ,prof41 killed1 #agec1 whilst experimenting1 #aba ,ridges1 metallic conductor covering1 #fh1 #agg ,rittenhouse1 ,dr41 of ,philadelphia1 his observations1 #ec ,rivets1 copper1 used for joints1 #bd ,robins1 ,e4 ,c41 his report1 #ci ,robertson1 ,j41 his report1 #gf ,rochon1 ,m41 his report1 #ea1 #eg ,rods better than ropes or chains1 #if1 #bjd solid copper1 #aj1 #ac1 #ad1 #ae1 #gc1 #hi1 #aag1 #abc1 #ahd1 #aie copper not fusible1 #abe copper1 their size1 #gj1 #ahj ,earth terminals of 7which see74 elevation1 how coupled1 #bd horizontal1 on roof1 #eb1 #aah how to be fastened to buildings1 7,see ,,attachment74 iron1 conductor1 #aj1 #df1 #dg1 #gg1 #ii1 #aag1 #agg tarred or galvanized1 #ajd the size of1 #eb1 #eh1 #gj1 #gd1 #acj ,joints in 7,see ,,joints74 ,lightning1 and how to construct them1 #ajb ,munson's1 #baf must be thoroughly joined1 #eb not to be inside chimney1 #aaa of greatest length gives most protection1 #acg of spirally twisted iron1 #aib ,points of 7,see ,,points74 should be painted 7,see ,,painted74 ,rods1 size of 7,see ,,conductor1 ,size of74 ,tie1 must be connected with conductor1 #fj to be diameter of chimney above top1 #aaa to be made of conical form1 #abi will not divert electric fire from its path1 #abe ,rome1 system of rods used there1 #agi ,roof1 all metals in1 to be connected1 #fj1 #gb covered with metal1 #cg1 #fi1 #agg lead1 easily made into protector1 #ajb of wood or slate has conductor on ridge1 #abe with masses of metal1 difficult to protect1 #g ,rope better than rod1 #e1 #aj1 #fj1 #aaa1 #aac1 #aca1 #bdc brass wire1 #fj1 #abd conductor1 how to fit to ship's rigging1 #f lower end of to be opened1 #aa1 #ae copper and zinc wire decayed1 #bje copper better than iron for towns1 #ai copper1 its advantages and disadvantages1 #h1 #ef1 #fc1 #aca1 #acd copper wire1 #aj1 #ac1 #ad1 #cd1 #cg1 #ci1 #fj1 #ge1 #ajc1 #abe1 #aca1 #bbe1 #bbf1 #bbg dimensions of1 #h1 #i1 #bbc has both surface and mass1 #af too expensive1 #eh easily bent without angles1 #ai joined1 diverted1 or lengthened1 #ai hemp1 for conductors1 #ef ,iron wire1 #ai1 #eh1 #fh1 #abe1 #bbg1 #bdc smashed1 #hf liable to corrosion on factory chimneys1 #abe of thick copper wire1 #bbf1 #bbi or cable1 fringed out at upper terminal1 #ad metallic1 disadvantages of1 #fb1 #fc1 #ie1 #bjd for connecting points with metal bars1 #ee with hemp strand in middle1 #aaf1 #bbg ,wire1 conductor1 badly erected1 #ci damaged1 #aic ,rosherville ,church struck though provided with a conductor1 #cd ,rounded and pointed conductors1 #gi center7,see ,,point47 ,route to earth for conductor1 #abf ,royal ,society1 ,committee of1 #gf1 #gh1 #gi ,rules for erecting ,conductors center7,see ,,instructions74 ,russell1 ,f4 ,co41 their answers1 #i1 #ag ,rust increases electrical resistance1 #gj1 #ajg ,sacr's1 ,m4 ,e41 system1 #adj ,safety from ,lightning1 ,personal1 #bcc ,st4 ,ann's ,hotel1 ,buxton1 struck1 #cd ,st4 ,aubyn1 ,j4 ,p41 #bi ,st4 ,clotilde ,church1 ,paris1 struck1 #fi ,st4 ,eloi ,church1 ,paris1 struck1 #fi ,st4 ,george's1 ,leicester1 #abf1 #bdj ,st4 ,james' ,church1 ,west-,end1 ,hants1 struck1 #cd ,st4 ,mary's1 ,crumpsall1 near ,manchester1 struck1 #ci ,st4 ,mark's1 ,venice1 #ajc ,st4 ,matthias's ,church1 ,brixton1 struck1 #ci ,st4 ,michael's ,church1 ,stamford1 struck1 #dc ,st4 ,paul's ,cathedral1 ,accident to1 #gh fitted with copper wire rope1 #aca its immunity from injury by lightning1 #ajc ,st4 ,peter's ,church1 ,brighton1 pinnacle struck1 #dh ,st4 ,sepulchre's ,church1 ,northampton1 struck1 #cg ,st4 ,sulpice ,church1 ,paris1 struck1 #fi ,sanderson ,co41 their answers1 #bc1 #bd 8,scientific ,american10 #aah ,screen1 metallic1 a protection1 #he ,secchi1 ,p41 #ahj ,sectional ,area 7,see ,,area1 ,,sectional74 ,sharp ,points 7,see ,,points74 ,sheets1 ,iron1 struck1 #ec ,sheet lightning is the reflection of forked1 #aja1 #bdb ,ships struck1 #ec1 #fa1 #fb1 #hh1 #ie1 #aie1 #bje conductors1 #f1 #ij1 #aba1 #abb1 #aie1 #aii1 #bjj ,short terminal points to chimneys1 #abe ,siemens1 ,a41 abstract by1 #abg ,silver ,points 7,see ,,points ,,of ,,silver74 ,simmons1 ,j41 his ,essay1 #ha ,size of conductor 7,see ,,conductor1 ,,size ,,of74 ,small conductor replaced by heavier one1 #aid ,smoke discharged from chimney a conductor1 #acb ,smoke often destroys brass1 #abd ,snell1 ,h4 ,s41 his report1 #ci ,soil1 change in nature of1 its effect1 #ga dry1 a non-conductor1 #gj metallic veins beneath1 #fa water beneath will attract lightning1 #fa ,soldered joints 7,see ,,joints74 ,solder1 objectionable1 #af the use of1 imperative1 #bj not universal1 #bj with copper1 #ajc ,solid rods superseded by ropes of wire 7,see ,,ropes71 #aca ,south ,foreland ,lighthouse1 #ahe1 #ahf ,spagnoletti1 ,mr41 discussion on lightning conductors1 #aca ,spang1 ,h4 ,w41 ,treatise on ,lightning ,conductors1 #aab1 #aha ,sparks from ,holtz's machine1 #ada ,ruhmkorff's coil1 #ada ,space protected 7,see ,,protection1 ,,area ,,of74 ,specific attraction1 equal in all bodies1 #gc heat of iron greater than copper1 #acb ,sphere1 ,metal1 on top of conductors1 #aaa ,spike of iron 7,see ,,point74 ,spiral twisted iron rods1 #aib ,spires1 ,church1 conductor for1 how fixed1 #bc ,spire1 ,church1 conductors for without joints1 #bd ,spires1 connection from bottom of vane rod1 #ad ,spout1 ,iron1 entered by lightning1 #dc ,spout split at joints1 #de1 #df1 #dg1 #di ,spratt's patent conductors1 #bje1 #baj1 #bae ,spurn ,point ,high ,light1 #ahd ,square building to have terminal at each end1 #abe wire1 #ac1 #baf ,staples for attaching conductor 7,see ,,attachment74 ,static discharges from conductors1 #acc electricity1 laws of1 #acb ,stays1 ,metal1 #ahd1ahe ,steeple of ,jacobi ,church1 at ,hamburg1 #abi ,steeples to have horizontal conductors1 #aac1 #abe ,steeple with lightning rod injured1 #abd1 #abe ,steinheil's lightning protector1 #acj ,sterriker1 ,john1 his report1 #de1 #df ,straps and nails 7,see ,,attachment74 ,strasbourg1 accident at1 #ii ,straw conductors for country use1 #ajd ,strata1 water bearing1 connection to be made with 7,see ,,earth ,,terminal74 ,stream of fire in rigging of ship1 #ed ,striking distance1 #fej to1 #fejj feet1 #ajh ,stroke1 lightning1 #i or1 #aj miles1 #ajh ,sullivan1 ,adml4 #ahc1 #aie1 #aii ,sulphur ,paste made of galena and melted1 for end of conductor1 #eh ,sulphurous fumes destructive to terminals1 #aca odour of lightning1 #he ,sun burner to lofty building1 #bja ,superficial conductors1 advantages of1 #hf ,supports of protector soldered with zinc1 #adj ,supposed perfect conductor1 #aca ,surface exposed to air considerable1 #aci or mass1 which conducts81 #ac1 #ae1 #ah1 #di1 #gd1 #hi1 #acb ,swan ,cotton ,mill1 #bci ,sweden1 accidents from lightning1 #abf ,symons1 ,g4 ,j41 #dc1 #df1 #ahc abstracts by1 #gd1 #hi1 #ii1 #ajb1 #ajd1 #aaa1 #aae1 #aca1 #acb1 #acd1 #ace ,tacchini1 ,prof41 #agi1 #ahj ,tait1 ,prof41 on thunderstorms1 #bda ,tanks1 #ae1 #ga1 #id1 #ajg1 #acj ,tape1 joints1 if any1 should be rivetted and soldered1 #g copper better than rope1 #h1 #bjd objections to1 #e1 #f1 #af let into masts1 #ib lower end to have a discharging fork1 #aa ,phin1 upon1 #ajc to be cut in strips for earth terminal1 #ae1 #bc copper1 the sizes and lengths made1 #g1 #aj1 #ad1 #bc1 #gj1 #acc cheaper than rope1 #h1 #i ,tarred casing of wood to enclose iron1 #abe metallic rope1 #fj ,taunton ,church1 large copper rope conductor1 #h ,teale1 ,f4 ,g41 of ,calcutta1 #aha ,telegraph instruments injured1 #ajj poles1 how protected1 #aja wires affected underground1 #aja ,temperature1 variations of1 affecting length of conductor1 #fh1 #abe1 #bbf ,terkelsen1 ,c41 abstract by1 #ajf ,terminal area protected by 7,see ,,protection1 ,,area ,,of74 ,terminals 7,see ,,points74 ,terminal1 earth 7,see ,,earth ,,terminal74 ,terminal for every1 #bj ft4 of roof1 #abe how fastened to roof1 #eb if numerous1 should have proportionately thicker conductor 7,see ,,area1 ,,sectional74 long upper1 #fh1 #gg1 #bbe1 #bbi jar roof by vibration by wind1 #aaf1 #abg not always pointed1 #ib1 #abe painted or tinned1 #ee rods1 #ag1 #ee1 #ff1 #fg1 #gb1 #abd to branch out at top center7,see ,,points74 ,upper1 how attached to conductor1 #fj fused1 #aic should be cased in lead to protect from sulphurous fumes1 #aca to be a round rod1 #abe to be iron or copper1 #hb too small1 #fb what it is1 #ei what made of1 #ac ,terra ,cotta water pipes1 #ahj ,testing apparatus1 #aaa1 #bbe1 #bbh1 #bdc1 #bdd of building as well as of conductor1 #i of conductors with galvanometer1 #i1 #aca to be periodical1 #acb1 #bdd ,theory of protection 7,see ,,protection1 ,,area ,,of74 ,thimbles1 glass1 #ahf ,thomson1 ,prof4 ,sir ,w41 on conductors1 #dg1 #dh1 #di1 #ajb1 #acc ,thunderstorms dangerous where no woods are1 #aai in ,france1 #ahbb1 #abc nature of1 #he ,ties1 ,metallic 7,see ,,attachment74 ,tin and lead conductors tried1 #abc ,tinfoil1 experiments with1 #aii ,tinned metallic wire1 #ie ,tips 7,see ,,points74 ,tomes1 ,j41 ,f4,r4,s11 accident to his house1 #baj ,top conductor 7,see ,,conductor ,,ridge74 ,torquay1 no good earth there1 #acj ,tower of church struck1 #bi of house struck1 #cg ,trees bad conductors1 #abg ,trees1 ,high1 their protective action1 #he1 #abg1 #bdc injured while passing lightning to better conductor1 #abg on plains attract lightning1 #abg struck1 #de1 #dg1 #di ,trenches1 ,connections in1 #gb filled with carbonaceous materials1 #g1 #ab1 #ajj1 #abe in rocky or dry soil1 #gb 7,see also ,,earth ,,terminals74 ,trough1 ,oaken1 for lower terminals to pass through1 #ef ,trinity ,house1 #ahc ,tube conductor for ,houses of ,parliament1 #aii ,copper1 #g1 #aj1 #ad1 #gj1 #gd1 #acc having copper cable passing through it1 #ac patent insertion joints1 #g ,iron1 #hf1 #aag conductors1 why objectionable1 #e ,turrets1 conductors for1 how fixed1 #bc1 #bd ,twyford ,moors1 near ,winchester1 #cd ,underground connection 7,see ,,earth ,,terminal74 ,united ,states1 accidents from lightning1 #abf ,university ,coll41 ,chimney struck1 #ch ,university of ,padua protected by conductors1 #abb ,upper terminal 7,see ,,terminal ,,upper and ,,points74 ,upwood ,gorse1 ,caterham1 accident at1 #baj ,vaillant1 ,le ,marchal1 his ,report1 #ff ,vanes1 how connected1 c41 #aj1 #aa1 #ad1 #bc1 #ci1 #dj1 #eb1 #ec1 #ajd1 #ahc1 #ahe1 #ahf1 #bjb ,varley1 ,c41 quoted1 #aja ,venetians decreed to use lightning rods in ,republic1 #abb ,ventilating pipes1 #baf ,vitreous tubes 7,fulgurites7 formed by electricity1 #aab ,vyle's1 ,s41 rod testing apparatus1 #bdd ,walker1 ,c4 ,v41 on conductors1 #hd on ,leyden discharges1 #hd ,j41 #ahg ,matthew1 ,his knot1 #af ,wall eyes of iron1 #acj center7,see also ,,attachment74 ,wandsworth1 chimney of house struck1 #ch ,ward1 ,g4 ,g41 of ,new ,york1 #aha ,water mains and underground water generally 7,see ,,earth ,,terminals74 ,water spouts to be connected1 #aj1 #bbf ,watson's1 ,dr41 conductor at ,payneshill1 #he for ships1 #aba report1 #gf1 #gi ,weathercock 7,see ,,vanes74 ,weber1 ,dr4 ,l41 on lightning discharges in ,schleswig ,holstein1 #abg1 #bca ,week1 ,st4 ,mary1 the ,church of1 #bi1 #cj ,weight of conductors 7,see ,,conductors1 ,,size ,,of74 ,wells 7,see ,,earth ,,terminals74 ,wells ,church1 ,norfolk1 destruction of1 by lightning1 #aid ,west side of house1 rod to be on1 #ajj ,wheatstone quoted1 on fusion of rod1 #hc ,whichcord1 ,j41 his joint ,report1 #bh ,white1 ,w4 ,h41 ,secretary ,r4,i4,b4,a41 circular signed by him1 #bh ,wilkins ,weatherby1 their answer1 #d-f1 #ag ,wilson1 ,mr41 his report and views1 #gf1 #gi ,wilson1 ,r41 on conductors on chimneys1 #aaj ,wind1 action of on conductors1 #aaf1 #abg ,windmill with conductor struck1 #abh ,windows1 copper1 to magazines1 #gd ,winkler1 ,prof4 ,j4 ,h4 7#agdf71 electricity cause of thunderstorm1 #abi ,wire cables 7,see ,,rope74 cage as protection without use of earth1 #acb melted into drops like shot1 #aie of zinc melted1 #ajg rusted in earth and was useless1 #ajg square1 #ac1 #baf ,withers1 ,j4 ,b4 ,m41 his report1 #dj ,wood to be creosoted to form case for iron1 #abe coated with resin1 as a conductor1 #ed ,workhouse1 how to be protected1 #aj ,wrexham ,church struck1 #abf ,wrottesley1 ,col4 ,g41 ,r4,e41 his report1 #dj ,wrought iron 7,see ,,iron74 ,wyatt ,papworth ,church struck1 #ci ,york1 accident at1 #bai ,zenger's1 ,prof4 ,c41 ,symmetrische ,blitzableiter1 #ajd ,zinc better conductor than iron1 #gd coating1 #gb chimney of house struck1 #cg cylinder1 wire to pass through1 #hc strips1 #aib wire melted1 #ajg ---------------------------------------- -------------------------------- ,,transcriber',s ,,notes #a4 ,p4 #agj1 changed 8,annals of ,electricity4 #aj vols4 #hvo4 #ahcfc-d0 to 8,annals of ,electricity4 #aj vols4 #hvo4 #ahcf04 #b4 ,silently corrected typographical errors and also variations in spelling4 #c4 ,retained anachronistic1 non-standard1 and uncertain spellings as printed4 #d4 ,enclosed italics font in underscores4 #e4 ,enclosed bold font in equals4 #f4 ,enclosed small font in currency signs4 #g4 ,superscripts are denoted by a caret before a single superscript character or a series of superscripted characters enclosed in curly braces1 e4g4 ,mr4 or ,mister4 #h4 ,subscripts are denoted by an underscore before a series of subscripted characters enclosed in curly braces1 e4g4 ,h#b,o4