,,! ,,inv5tions ,,rese>*es ,,& ,,writ+s ,,( ,,nikola ,,tesla ,,to ,,8 ,,c\ntrym5 ,,9 ,,ea/]n ,,europe ,,?is ,,record ,,( ,,! ,,"w ,,already ,,accompli%$ ,,by ,,nikola ,,tesla ,,is ,,respectfully ,,d$icat$ ,illu/ration3 ,nikola ,tesla ,,! ,,inv5tions ,,rese>*es ,,& ,,writ+s ,,( ,,nikola ,,tesla ,,) ,,special ,,ref]5ce ,,to ,,8 ,,"w ,,9 ,,polyphase ,,curr5ts ,,& ,,high ,,pot5tial ,,light+ ,,by ,,?omas ,,comm]=d ,,m>t9 ,editor ,,! ,,electrical ,,eng9e]2 ,pa/-,presid5t ,am]ican ,in/itute ,electrical ,eng9e]s #ahid ,,! ,,electrical ,,eng9e] ,,new ,,york ,d4 ,,van ,,no/r& ,,company1 ,,new ,,york4 ,ent]$ accord+ to ,act ( ,congress 9 ! ye> #ahic by ,t4 ,c4 ,,m>t9 9 ! (fice ( ! ,libr>ian ( ,congress at ,wa%+ton ,press ( ,mc,ilroy ,emmet1 #cf ,cortl&t ,/41 ,n4 ,y4 ,,preface4 ,! electrical problems ( ! pres5t day lie l>gely 9 ! economical transmission ( p[] & 9 ! radical improvem5t ( ! means & me?ods ( illum9ation4 ,to _m work]s & ?9k]s 9 ! doma9 ( electrical inv5tion1 ! app>atus & devices t are famili>1 appe> cumbr\s & wa/eful1 & subject to sev]e limitations4 ,!y believe t ! pr9ciples ( curr5t g5]ation mu/ be *ang$1 ! area ( curr5t supply be enl>g$1 & ! appliances us$ by ! consum] be at once *eap5$ & simplifi$4 ,! brilliant successes ( ! pa/ ju/ify !m 9 e expectancy ( /ill m g5]\s fruition4 ,! pres5t volume is a simple record ( ! pione] "w done 9 su* dep>tm5ts up to date1 by ,mr4 ,nikola ,tesla1 9 :om ! _w has already recogniz$ "o ( ! =emo/ ( mod]n electrical inve/igators & inv5tors4 ,no attempt :atev] has be5 made "h to emphasize ! importance ( 8 rese>*es & discov]ies4 ,great ideas & real inv5tions w9 _! own way1 det]m9+ _! own place by intr9sic m]it4 ,b ) ! conviction t ,mr4 ,tesla is blaz+ a pa? t electrical developm5t mu/ foll[ = _m ye>s to come1 ! compil] has endeavor$ to br+ toge!r all t be>s ! impress ( ,mr4 ,tesla's g5ius1 & is wor?y ( pres]vation4 ,aside f its value z %[+ ! scope ( 8 inv5tions1 ?is volume may be ( s]vice z indicat+ ! range ( 8 ?\ght4 ,!re is intellectual pr(it 9 /udy+ ! pu% & play ( a vigor\s & orig9al m9d4 ,al?\gh ! lively int]e/ ( ! public 9 ,mr4 ,tesla's "w is p]haps ( rec5t gr[?1 ?is volume cov]s ! results ( full t5 ye>s4 ,x includes 8 lectures1 miscellane\s articles & discussions1 & makes note ( all 8 inv5tions ?us f> kn[n1 p>ticul>ly ^? be>+ on polyphase motors & ! effects obta9$ ) curr5ts ( high pot5tial & high frequ5cy4 ,x w be se5 t ,mr4 ,tesla has ev] press$ =w>d1 b>ely paus+ = an in/ant to "w out 9 detail ! utilizations t h at once be5 obvi\s to him ( ! new pr9ciples he has elucidat$4 ,:]ev] possible 8 own language has be5 employ$4 ,x may be add$ t ?is volume is issu$ ) ,mr4 ,tesla's sanction & approval1 & t p]mission has be5 obta9$ = ! re-publication 9 x ( su* pap]s z h be5 read be=e v>i\s te*nical societies ( ?is c\ntry & ,europe4 ,mr4 ,tesla has k9dly favor$ ! au?or by look+ ov] ! pro( %eets ( ! sections embody+ 8 late/ rese>*es4 ,! "w has also enjoy$ ! c>eful revision ( ! au?or's fri5d & editorial associate1 ,mr4 ,joseph ,wetzl]1 ?r\gh ^: h&s all ! pro(s h pass$4 ,,decemb]1 #ahic4 ,t4 ,c4 ,m4 ,,cont5ts4 ,,"p ,i4 ,,polyphase ,,curr5ts4 ,,*apt] ,i4 ,,biographical ,,& ,,introductory4 #c ,,*apt] ,,ii4 ,a ,,new ,,sy/em ,,( ,,alt]nat+ ,,curr5t ,,motors ,,& ,,trans=m]s4 #g ,,*apt] ,,iii4 ,,! ,,tesla ,,rotat+ ,,magnetic ,,field4--,,motors ,,) ,,clos$ ,,conductors4--,,syn*roniz+ ,,motors4--,,rotat+ ,,field ,,trans=m]s4 #i ,,*apt] ,,iv4 ,,modifications ,,& ,,expansions ,,( ,,! ,,tesla ,,polyphase ,,sy/ems4 #bf ,,*apt] ,v4 ,,utiliz+ ,,famili> ,,types ,,( ,,g5]ators ,,( ,,! ,,cont9u\s ,,curr5t ,,type4 #ca ,,*apt] ,,vi4 ,,me?od ,,( ,,obta9+ ,,desir$ ,,spe$ ,,( ,,motor ,,or ,,g5]ator4 #cf ,,*apt] ,,vii4 ,,regulator ,,= ,,rot>y ,,curr5t ,,motors4 #de ,,*apt] ,,viii4 ,,s+le ,,circuit1 ,,self-,,/>t+ ,,syn*roniz+ ,,motors4 #ej ,,*apt] ,,ix4 ,,*ange ,,f ,,d\ble ,,curr5t ,,to ,,s+le ,,curr5t ,,motors4 #ef ,,*apt] ,x4 ,,motor ,,) ,,curr5t ,,lag ,,artificially ,,secur$4 #eh ,,*apt] ,,xi4 ,,ano!r ,,me?od ,,( ,,trans=mation ,,f ,a ,,torque ,,to ,a ,,syn*roniz+ ,,motor4 #fb ,,*apt] ,,xii4 ,,magnetic ,,lag ,,motor4 #fg ,,*apt] ,,xiii4 ,,me?od ,,( ,,obta9+ ,,diff]5ce ,,( ,,phase ,,by ,,magnetic ,,%ield+4 #ga ,,*apt] ,,xiv4 ,,type ,,( ,,tesla ,,s+le-,,phase ,,motor4 #gf ,,*apt] ,,xv4 ,,motors ,,) ,,circuits ,,( ,,diff]5t ,,resi/ance4 #gi ,,*apt] ,,xvi4 ,,motor ,,) ,,equal ,,magnetic ,,en]gies ,,9 ,,field ,,& ,,armature4 #ha ,,*apt] ,,xvii4 ,,motors ,,) ,,co9cid+ ,,maxima ,,( ,,magnetic ,,effect ,,9 ,,armature ,,& ,,field4 #hc ,,*apt] ,,xviii4 ,,motor ,,bas$ ,,on ,,! ,,diff]5ce ,,( ,,phase ,,9 ,,! ,,magnetization ,,( ,,! ,,inn] ,,& ,,out] ,,p>ts ,,( ,,an ,,iron ,,core4 #hh ,,*apt] ,,xix4 ,,ano!r ,,type ,,( ,,tesla ,,induction ,,motor4 #ib ,,*apt] ,,xx4 ,,comb9ations ,,( ,,syn*roniz+ ,,motor ,,& ,,torque ,,motor4 #ie ,,*apt] ,,xxi4 ,,motor ,,) ,a ,,cond5s] ,,9 ,,! ,,armature ,,circuit4 #aja ,,*apt] ,,xxii4 ,,motor ,,) ,,cond5s] ,,9 ,,"o ,,( ,,! ,,field ,,circuits4 #ajf ,,*apt] ,,xxiii4 ,,tesla ,,polyphase ,,trans=m]4 #aji ,,*apt] ,,xxiv4 ,a ,,con/ant ,,curr5t ,,trans=m] ,,) ,,magnetic ,,%ield ,,betwe5 ,,coils ,,( ,,prim>y ,,& ,,second>y4 #aac ,,"p ,,ii4 ,,! ,,tesla ,,effects ,,) ,,high ,,frequ5cy ,,& ,,high ,,pot5tial ,,curr5ts4 ,,*apt] ,,xxv4 ,,introductory4--,,! ,,scope ,,( ,,! ,,tesla ,,lectures4 #aai ,,*apt] ,,xxvi4 ,,! ,,new ,,york ,,lecture4 ,,exp]im5ts ,,) ,,alt]nate ,,curr5ts ,,( ,,v ,,high ,,frequ5cy1 ,,& ,,_! ,,application ,,to ,,me?ods ,,( ,,artificial ,,illum9ation1 ,,may #bj1 #ahia4 #ade ,,*apt] ,,xxvii4 ,,! ,,london ,,lecture4 ,,exp]im5ts ,,) ,,alt]nate ,,curr5ts ,,( ,,high ,,pot5tial ,,& ,,high ,,frequ5cy1 ,,febru>y #c1 #ahib4 #aih ,,*apt] ,,xxviii4 ,,! ,,philadelphia ,,& ,,/4 ,,l\is ,,lecture4 ,,on ,,light ,,& ,,o!r ,,high ,,frequ5cy ,,ph5om5a1 ,,febru>y ,,& ,,m>*1 #ahic4 #bid ,,*apt] ,,xxix4 ,,tesla ,,alt]nat+ ,,curr5t ,,g5]ators ,,= ,,high ,,frequ5cy4 #cgd ,,*apt] ,,xxx4 ,,alt]nate ,,curr5t ,,electro/atic ,,induction ,,app>atus4 #cib ,,*apt] ,,xxxi4 ,,massage ,,) ,,curr5ts ,,( ,,high ,,frequ5cy4 #cid ,,*apt] ,,xxxii4 ,,electric ,,dis*>ge ,,9 ,,vacuum ,,tubes4 #cif ,,"p ,,iii4 ,,miscellane\s ,,inv5tions ,,& ,,writ+s4 ,,*apt] ,,xxxiii4 ,,me?od ,,( ,,obta9+ ,,direct ,,f ,,alt]nat+ ,,curr5ts4 #dji ,,*apt] ,,xxxiv4 ,,cond5s]s ,,) ,,plates ,,9 ,,oil4 #dah ,,*apt] ,,xxxv4 ,,electrolytic ,,regi/]+ ,,met]4 #dbj ,,*apt] ,,xxxvi4 ,,!rmo-,,magnetic ,,motors ,,& ,,pyro-,,magnetic ,,g5]ators4 #dbd ,,*apt] ,,xxxvii4 ,,anti-,,sp>k+ ,,dynamo ,,bru% ,,& ,,commutator4 #dcb ,,*apt] ,,xxxviii4 ,,auxili>y ,,bru% ,,regulation ,,( ,,direct ,,curr5t ,,dynamos4 #dch ,,*apt] ,,xxxix4 ,,improvem5t ,,9 ,,dynamo ,,& ,,motor ,,con/ruction4 #ddh ,,*apt] ,,xl4 ,,tesla ,,direct ,,curr5t ,,arc ,,light+ ,,sy/em4 #dea ,,*apt] ,,xli4 ,,improvem5t ,,9 ,,unipol> ,,g5]ators4 #dfe ,,"p ,,iv4 ,,app5dix3 ,,e>ly ,,phase ,,motors ,,& ,,! ,,tesla ,,oscillators4 ,,*apt] ,,xlii4 ,,mr4 ,,tesla',s ,,p]sonal ,,exhibit ,,at ,,! ,,_w',s ,,fair4 #dgg ,,*apt] ,,xliii4 ,,! ,,tesla ,,me*anical ,,& ,,electrical ,,oscillators4 #dhf ,,"p ,i4 ,,polyphase ,,curr5ts4 ,,*apt] ,i4 ,,biographical ,,& ,,introductory4 ,z an introduction to ! record conta9$ 9 ?is volume ( ,mr4 ,tesla's inve/igations & discov]ies1 a few words ( a biographical nature w1 x is deem$1 n be out ( place1 nor o!r ?an welcome4 ,nikola ,tesla 0 born 9 #aheg at ,smiljan1 ,lika1 a bord]l& region ( ,au/ro-,hung>y1 ( ! ,s]bian race1 :i* has ma9ta9$ aga9/ ,turkey & all com]s s unceas+ a /ruggle = fre$om4 ,8 family is an old & repres5tative "o among ^! ,switz]s ( ,ea/]n ,europe1 & 8 fa!r 0 an eloqu5t cl]gyman 9 ! ,greek ,*ur*4 ,an uncle is to-day ,metropolitan 9 ,bosnia4 ,8 "m 0 a woman ( inh]it$ +5uity1 & delight$ n only 9 skilful "w ( ! ord9>y h\sehold "*1 b 9 ! con/ruction ( su* me*anical appliances z looms & *urns & o!r ma*9]y requir$ 9 a rural community4 ,nikola 0 educat$ at ,gospi* 9 ! public s*ool = f\r ye>s1 & !n sp5t ?ree ye>s 9 ! ,real ,s*ule4 ,he 0 !n s5t to ,c>/att1 ,croatia1 :]e he cont9u$ 8 /udies = ?ree ye>s 9 ! ,high] ,real ,s*ule4 ,!re = ! fir/ "t he saw a /eam locomotive4 ,he graduat$ 9 #ahgc1 &1 surviv+ an attack ( *ol]a1 devot$ himself to exp]im5tation1 especially 9 electricity & magnetism4 ,8 fa!r w\ld h _h him ma9ta9 ! family tradition by ent]+ ! ,*ur*1 b native g5ius 0 too /rong1 & he 0 all[$ to ent] ! ,polyte*nic ,s*ool at ,gratz1 to f9i% 8 /udies1 & ) ! object ( becom+ a pr(essor ( ma!matics & physics4 ,"o ( ! ma*9es !re exp]im5t$ ) 0 a ,gramme dynamo1 us$ z a motor4 ,despite 8 in/ructor's p]fect demon/ration ( ! fact t x 0 impossible to op]ate a dynamo )\t commutator or bru%es1 ,mr4 ,tesla c\ld n be conv9c$ t su* accessories 7 necess>y or desirable4 ,he _h already se5 ) quick intuition t a way c\ld be f\nd to disp5se ) !m2 & f t "t he may be said to h begun "w on ! ideas t fructifi$ ultimately 9 8 rotat+ field motors4 ,9 ! second ye> ( 8 ,gratz c\rse1 ,mr4 ,tesla gave up ! notion ( becom+ a tea*]1 & took up ! eng9e]+ curriculum4 ,8 /udies end$1 he return$ home 9 "t to see 8 fa!r die1 & !n w5t to ,prague & ,buda-,pe/h to /udy languages1 ) ! object ( qualify+ himself broadly = ! practice ( ! eng9e]+ pr(ession4 ,= a %ort "t he s]v$ z an assi/ant 9 ! ,gov]nm5t ,telegraph ,eng9e]+ ,dep>tm5t1 & !n became associat$ ) ,m4 ,puskas1 a p]sonal & family fri5d1 & o!r exploit]s ( ! telephone 9 ,hung>y4 ,he made a numb] ( telephonic inv5tions1 b f\nd 8 opportunities ( b5efit+ by !m limit$ 9 v>i\s ways4 ,to ga9 a wid] field ( action1 he pu%$ on to ,p>is & !re secur$ employm5t z an electrical eng9e] ) "o ( ! l>ge companies 9 ! new indu/ry ( electric light+4 ,x 0 dur+ ?is p]iod1 & z e>ly z #ahhb1 t he began s]i\s & cont9u$ ef=ts to embody ! rotat+ field pr9ciple 9 op]ative app>atus4 ,he 0 en?usia/ic ab\t x2 believ$ x to m>k a new dep>ture 9 ! electrical arts1 & c\ld ?9k ( no?+ else4 ,9 fact1 b = ! solicitations ( a few fri5ds 9 comm]cial circles :o urg$ him to =m a company to exploit ! inv5tion1 ,mr4 ,tesla1 !n a y\? ( little worldly exp]i5ce1 w\ld h s\ght an imm$iate opportunity to publi% 8 ideas1 believ+ !m to be wor?y ( note z a novel & radical advance 9 electrical !ory z well z de/9$ to h a pr(\nd influ5ce on all dynamo electric ma*9]y4 ,at la/ he det]m9$ t x w\ld be be/ to try 8 =tunes 9 ,am]ica4 ,9 ,france he _h met _m ,am]icans1 & 9 contact ) !m le>n$ ! desirability ( turn+ e new idea 9 electricity to practical use4 ,he le>n$ also ( ! ready enc\ragem5t giv5 9 ! ,unit$ ,/ates to any inv5tor :o c\ld atta9 "s new & valuable result4 ,! resolution 0 =m$ ) *>act]i/ic quickness1 & ab&on+ all 8 prospects 9 ,europe1 he at once set 8 face we/w>d4 ,arriv$ 9 ! ,unit$ ,/ates1 ,mr4 ,tesla took (f 8 coat ! day he arriv$1 9 ! ,edison ,works4 ,t place _h be5 a goal ( 8 ambition1 & "o c readily imag9e ! b5efit & /imulus d]iv$ f association ) ,mr4 ,edison1 = :om ,mr4 ,tesla has always _h ! /ronge/ admiration4 ,x 0 impossible1 h[ev]1 t1 ) 8 own ideas to c>ry out1 & 8 own inv5tions to develop1 ,mr4 ,tesla c\ld long rema9 9 ev5 ! mo/ delightful employ2 &1 8 "w n[ attract+ att5tion1 he left ! ,edison ranks to jo9 a company int5d$ to make & sell an arc light+ sy/em bas$ on "s ( 8 inv5tions 9 t bran* ( ! art4 ,) unceas+ dilig5ce he br\ght ! sy/em to p]fection1 & saw x plac$ on ! m>ket4 ,b ! ?+ :i* mo/ occupi$ 8 "t & ?\ghts1 h[ev]1 all ?r\gh ?is p]iod1 0 8 old discov]y ( ! rotat+ field pr9ciple = alt]nat+ curr5t "w1 & ! application ( x 9 motors t h n[ become kn[n ! _w ov]4 ,/rong z 8 convictions on ! subject !n 71 x is a fact t he /ood v mu* alone1 = ! alt]nat+ curr5t _h no well recogniz$ place4 ,few electrical eng9e]s _h ev] us$ x1 & ! majority 7 entirely unfamili> ) its value1 or ev5 its ess5tial features4 ,ev5 ,mr4 ,tesla himself did n1 until aft] protract$ ef=t & exp]im5tation1 le>n h[ to con/ruct alt]nat+ curr5t app>atus ( fair effici5cy4 ,b t he _h accompli%$ 8 purpose 0 %[n by ! te/s ( ,pr(4 ,an?ony1 made 9 ! ( w9t] #ahhg-h1 :5 ,tesla motors 9 ! h&s ( t di/+ui%$ exp]t gave an effici5cy equal to t ( direct curr5t motors4 ,no?+ n[ /ood 9 ! way ( ! comm]cial developm5t & introduction ( su* motors1 except t !y _h to be con/ruct$ ) a view to op]at+ on ! circuits !n exi/+1 :i* 9 ?is c\ntry 7 all ( high frequ5cy4 ,! fir/ full publication ( 8 "w 9 ?is direction--outside 8 pat5ts--0 a pap] read be=e ! ,am]ican ,in/itute ( ,electrical ,eng9e]s 9 ,new ,york1 9 ,may1 #ahhh 7read at ! sugge/ion ( ,pr(4 ,an?ony & ! pres5t writ]71 :5 he exhibit$ motors t _h be5 9 op]ation long previ\s1 & ) :i* 8 belief t bru%es & commutators c\ld be disp5s$ )1 0 triumphantly prov$ to be correct4 ,! section ( ?is volume devot$ to ,mr4 ,tesla's inv5tions 9 ! utilization ( polyphase curr5ts w %[ h[ ?or\ghly f ! outset he _h ma/]$ ! fundam5tal idea & appli$ x 9 ! greate/ v>iety ( ways4 ,hav+ not$ = ye>s ! _m advantages obta9able ) alt]nat+ curr5ts1 ,mr4 ,tesla 0 naturally l$ on to exp]im5t ) !m at high] pot5tials & high] frequ5cies ?an 7 common or approv$ (4 ,ev] press+ =w>d to det]m9e 9 ev5 ! slighte/ degree ! outl9es ( ! unkn[n1 he 0 rew>d$ v quickly 9 ?is field ) results ( ! mo/ surpris+ nature4 ,a slight acqua9tance ) "s ( ^! exp]im5ts l$ ! compil] ( ?is volume to urge ,mr4 ,tesla to repeat !m be=e ! ,am]ican ,in/itute ( ,electrical ,eng9e]s4 ,?is 0 done 9 ,may1 #ahia1 9 a lecture t m>k$1 beyond "q1 a di/9ct dep>ture 9 electrical !ory & practice1 & all ! results ( :i* h n yet made !mselves fully app>5t4 ,! ,new ,york lecture1 & its successors1 two 9 numb]1 are also includ$ 9 ?is volume1 ) a few supplem5t>y notes4 ,mr4 ,tesla's "w ranges f> beyond ! va/ dep>tm5ts ( polyphase curr5ts & high pot5tial light+4 ,! ,miscellane\s section ( ?is volume includes a great _m o!r inv5tions 9 arc light+1 trans=m]s1 pyro-magnetic g5]ators1 !rmo-magnetic motors1 ?ird-bru% regulation1 improvem5ts 9 dynamos1 new =ms ( inc&esc5t lamps1 electrical met]s1 cond5s]s1 unipol> dynamos1 ! conv]sion ( alt]nat+ into direct curr5ts1 etc4 ,x is ne$less to say t at ?is mom5t ,mr4 ,tesla is engag$ on a numb] ( int]e/+ ideas & inv5tions1 to be made public 9 due c\rse4 ,! pres5t volume deals simply ) 8 "w accompli%$ to date4 ,,*apt] ,,ii4 ,a ,,new ,,sy/em ,,( ,,alt]nat+ ,,curr5t ,,motors ,,& ,,trans=m]s4 ,! pres5t section ( ?is volume deals ) polyphase curr5ts1 & ! inv5tions by ,mr4 ,tesla1 made kn[n ?us f>1 9 :i* he has embodi$ "o feature or ano!r ( ! broad pr9ciple ( rotat+ field poles or resultant attraction ex]t$ on ! armature4 ,x is ne$less to rem9d electricians ( ! great int]e/ ar\s$ by ! fir/ enunciation ( ! rotat+ field pr9ciple1 or to dwell ^u ! importance ( ! advance f a s+le alt]nat+ curr5t1 to me?ods & app>atus :i* deal ) m ?an "o4 ,simply prefac+ ! consid]ation "h attempt$ ( ! subject1 ) ! rem>k t 9 n[ise is ! object ( ?is volume ( a polemic or controv]sial nature1 x may be po9t$ out t ,mr4 ,tesla's "w has n at all be5 fully und]/ood or realiz$ up to date4 ,to _m read]s1 x is believ$1 ! analysis ( :at he has done 9 ?is dep>tm5t w be a revelation1 :ile x w at ! same "t illu/rate ! beautiful flexibility & range ( ! pr9ciples involv$4 ,x w be se5 t1 z j sugge/$1 ,mr4 ,tesla did n /op %ort at a m]e rotat+ field1 b dealt broadly ) ! %ift+ ( ! resultant attraction ( ! magnets4 ,x w be se5 t he w5t on to evolve ! multiphase sy/em ) _m ramifications & turns2 t he %[$ ! broad idea ( motors employ+ curr5ts ( diff]+ phase 9 ! armature ) direct curr5ts 9 ! field2 t he fir/ describ$ & work$ out ! idea ( an armature ) a body ( iron & coils clos$ ^u !mselves2 t he work$ out bo? syn*roniz+ & torque motors2 t he expla9$ & illu/rat$ h[ ma*9es ( ord9>y con/ruction might be adapt$ to 8 sy/em2 t he employ$ cond5s]s 9 field & armature circuits1 & w5t to ! bottom ( ! fundam5tal pr9ciples1 te/+1 approv+ or reject+1 x w\ld appe>1 e detail t inv5tive +5uity c\ld hit ^u4 ,n[ t op9ion is turn+ s emphatically 9 favor ( l[] frequ5cies1 x des]ves special note t ,mr4 ,tesla e>ly recogniz$ ! importance ( ! l[ frequ5cy feature 9 motor "w4 ,9 fact 8 fir/ motors exhibit$ publicly--& :i*1 z ,pr(4 ,an?ony %[$ 9 8 te/s 9 ! w9t] ( #ahhg-h1 7 ! equal ( direct curr5t motors 9 effici5cy1 output & />t+ torque--7 ( ! l[ frequ5cy type4 ,! necessity aris+1 h[ev]1 to utilize ^! motors 9 connection ) ! exi/+ high frequ5cy circuits1 our survey reveals 9 an int]e/+ mann] ,mr4 ,tesla's f]tility ( res\rce 9 ?is direction4 ,b t1 aft] exhau/+ all ! possibilities ( ?is field1 ,mr4 ,tesla returns to l[ frequ5cies1 & insi/s on ! sup]iority ( 8 polyphase sy/em 9 alt]nat+ curr5t di/ribution1 ne$ n at all surprise u1 9 view ( ! /r5g? ( 8 convictions1 s (t5 express$1 on ?is subject4 ,?is is1 inde$1 significant1 & may be reg>d$ z indicative ( ! probable developm5t next to be witness$4 ,incid5tal ref]5ce has be5 made to ! effici5cy ( rotat+ field motors1 a matt] ( mu* importance1 ?\gh x is n ! int5tion to dwell ^u x "h4 ,pr(4 ,an?ony 9 8 rem>ks be=e ! ,am]ican ,in/itute ( ,electrical ,eng9e]s1 9 ,may1 #ahhh1 on ! two small ,tesla motors !n %[n1 :i* he _h te/$1 /at$ t "o gave an effici5cy ( ab\t #ej p] c5t4 & ! o!r a little ov] sixty p] c5t4 ,9 #ahhi1 "s te/s 7 report$ f ,pittsburgh1 made by ,mr4 ,tesla & ,mr4 ,alb]t ,s*mid1 on motors up to #aj ,h4 ,p4 & weigh+ ab\t #hej p\nds4 ,^! ma*9es %[$ an effici5cy ( ne>ly #ij p] c5t4 ,) "s l>g] motors x 0 !n f\nd practicable to obta9 an effici5cy1 ) ! ?ree wire sy/em1 up to z high z #id & #ie p] c5t4 ,^! int]e/+ figures1 :i*1 ( c\rse1 might be supplem5t$ by o!rs m elaborate & ( lat] date1 are cit$ to %[ t ! effici5cy ( ! sy/em has n _h to wait until ! pres5t late day = any demon/ration ( its comm]cial usefulness4 ,an inv5tion is none ! less beautiful because x may lack utility1 b x mu/ be a pleasure to any inv5tor to "k t ! ideas he is advanc+ are fraught ) sub/antial b5efits to ! public4 ,,*apt] ,,iii4 ,,! ,,tesla ,,rotat+ ,,magnetic ,,field4--,,motors ,,) ,,clos$ ,,conductors4--,,syn*roniz+ ,,motors4--,,rotat+ ,,field ,,trans=m]s4 ,! be/ description t c be giv5 ( :at he attempt$1 & succe$$ 9 do+1 ) ! rotat+ magnetic field1 is to be f\nd 9 ,mr4 ,tesla's brief pap] explanatory ( 8 rot>y curr5t1 polyphase sy/em1 read be=e ! ,am]ican ,in/itute ( ,electrical ,eng9e]s1 9 ,new ,york1 9 ,may1 #ahhh1 "u ! title ,a ,new ,sy/em ( ,alt]nate ,curr5t ,motors & ,trans=m]s4 ,z a matt] ( fact1 :i* a p]usal ( ! pap] w e/abli%1 ,mr4 ,tesla made no attempt 9 t pap] to describe all 8 "w4 ,x dealt 9 reality ) ! few topics enum]at$ 9 ! caption ( ?is *apt]4 ,mr4 ,tesla's retic5ce 0 no d\bt due l>gely to ! fact t 8 action 0 gov]n$ by ! wi%es ( o!rs ) :om he 0 associat$1 b x may be wor? m5tion t ! compil] ( ?is volume--:o _h se5 ! motors runn+1 & :o 0 !n *airman ( ! ,in/itute ,committee on ,pap]s & ,meet+s--_h great difficulty 9 induc+ ,mr4 ,tesla to give ! ,in/itute any pap] at all4 ,mr4 ,tesla 0 ov]work$ & ill1 & manife/$ ! greate/ reluctance to an exhibition ( 8 motors1 b 8 objections 7 at la/ ov]come4 ,! pap] 0 writt5 ! night previ\s to ! meet+1 9 p5cil1 v ha/ily1 & "u ! pressure j m5tion$4 ,9 ?is pap] casual ref]5ce 0 made to two special =ms ( motors n )9 ! gr\p to be consid]$4 ,^! two =ms 73 #a4 ,a motor ) "o ( its circuits 9 s]ies ) a trans=m]1 & ! o!r 9 ! second>y ( ! trans=m]4 #b4 ,a motor hav+ its armature circuit connect$ to ! g5]ator1 & ! field coils clos$ ^u !mselves4 ,! pap] 9 its ess5ce is z foll[s1 deal+ ) a few lead+ features ( ! ,tesla sy/em1 namely1 ! rotat+ magnetic field1 motors ) clos$ conductors1 syn*roniz+ motors1 & rotat+ field trans=m]s3-- ,! subject :i* ,i n[ h ! pleasure ( br++ to y\r notice is a novel sy/em ( electric di/ribution & transmission ( p[] by means ( alt]nate curr5ts1 af=d+ peculi> advantages1 p>ticul>ly 9 ! way ( motors1 :i* ,i am confid5t w at once e/abli% ! sup]ior adaptability ( ^! curr5ts to ! transmission ( p[] & w %[ t _m results h]et(ore unatta9able c be rea*$ by _! use2 results :i* are v mu* desir$ 9 ! practical op]ation ( su* sy/ems1 & :i* _c be accompli%$ by means ( cont9u\s curr5ts4 ,be=e go+ into a detail$ description ( ?is sy/em1 ,i ?9k x necess>y to make a few rem>ks ) ref]5ce to c]ta9 conditions exi/+ 9 cont9u\s curr5t g5]ators & motors1 :i*1 al?\gh g5]ally kn[n1 are frequ5tly disreg>d$4 ,9 our dynamo ma*9es1 x is well kn[n1 we g5]ate alt]nate curr5ts :i* we direct by means ( a commutator1 a complicat$ device &1 x may be ju/ly said1 ! s\rce ( mo/ ( ! tr\bles exp]i5c$ 9 ! op]ation ( ! ma*9es4 ,n[1 ! curr5ts s direct$ _c be utiliz$ 9 ! motor1 b !y mu/--aga9 by means ( a simil> unreliable device--be reconv]t$ into _! orig9al /ate ( alt]nate curr5ts4 ,! function ( ! commutator is entirely ext]nal1 & 9 no way does x affect ! int]nal work+ ( ! ma*9es4 ,9 reality1 !re=e1 all ma*9es are alt]nate curr5t ma*9es1 ! curr5ts appe>+ z cont9u\s only 9 ! ext]nal circuit dur+ _! transit f g5]ator to motor4 ,9 view simply ( ?is fact1 alt]nate curr5ts w\ld comm5d !mselves z a m direct application ( electrical en]gy1 & ! employm5t ( cont9u\s curr5ts w\ld only be ju/ifi$ if we _h dynamos :i* w\ld prim>ily g5]ate1 & motors :i* w\ld be directly actuat$ by1 su* curr5ts4 ,b ! op]ation ( ! commutator on a motor is tw(old2 fir/1 x rev]ses ! curr5ts ?r\gh ! motor1 & secondly1 x effects automatically1 a progressive %ift+ ( ! poles ( "o ( its magnetic con/itu5ts4 ,assum+1 !re=e1 t bo? ( ! useless op]ations 9 ! sy/ems1 t is to say1 ! direct+ ( ! alt]nate curr5ts on ! g5]ator & rev]s+ ! direct curr5ts on ! motor1 be elim9at$1 x w\ld /ill be necess>y1 9 ord] to cause a rotation ( ! motor1 to produce a progressive %ift+ ( ! poles ( "o ( its elem5ts1 & ! "q pres5t$ itself--,h[ to p]=m ?is op]ation by ! direct action ( alt]nate curr5ts8 ,i w n[ proce$ to %[ h[ ?is result 0 accompli%$4 ,illu/ration3 ,,fig4 #a4 ,illu/ration3 ,,fig4 #a;a4 ,illu/ration3 ,,fig4 #b4 ,illu/ration3 ,,fig4 #b;a4 ,9 ! fir/ exp]im5t a drum-armature 0 provid$ ) two coils at "r angles to ea* o!r1 & ! ends ( ^! coils 7 connect$ to two pairs ( insulat$ contact-r+s z usual4 ,a r+ 0 !n made ( ?9 insulat$ plates ( %eet-iron & w\nd ) f\r coils1 ea* two opposite coils be+ connect$ toge!r s z to produce free poles on diametrically opposite sides ( ! r+4 ,! rema9+ free ends ( ! coils 7 !n connect$ to ! contact-r+s ( ! g5]ator armature s z to =m two indep5d5t circuits1 z indicat$ 9 ,fig4 #i4 ,x may n[ be se5 :at results 7 secur$ 9 ?is comb9ation1 & ) ?is view ,i w\ld ref] to ! diagrams1 ,figs4 #a to #h;a4 ,! field ( ! g5]ator be+ indep5d5tly excit$1 ! rotation ( ! armature sets up curr5ts 9 ! coils ,c ,c#a1 v>y+ 9 /r5g? & direction 9 ! well-kn[n mann]4 ,9 ! position %[n 9 ,fig4 #a1 ! curr5t 9 coil ,c is nil1 :ile coil ,c#a is trav]s$ by its maximum curr5t1 & ! connections may be su* t ! r+ is magnetiz$ by ! coils c#a c#a1 z indicat$ by ! lett]s ,n ,s 9 ,fig4 #a;a1 ! magnetiz+ effect ( ! coils c c be+ nil1 s9ce ^! coils are includ$ 9 ! circuit ( coil ,c4 ,illu/ration3 ,,fig4 #c4 ,illu/ration3 ,,fig4 #c;a4 ,9 ,fig4 #b1 ! armature coils are %[n 9 a m advanc$ position1 "o-eigh? ( "o revolution be+ complet$4 ,fig4 #b;a illu/rates ! correspond+ magnetic condition ( ! r+4 ,at ?is mom5t ! coil ,c#a g5]ates a curr5t ( ! same direction z previ\sly1 b weak]1 produc+ ! poles n#a s#a ^u ! r+2 ! coil ,c also g5]ates a curr5t ( ! same direction1 & ! connections may be su* t ! coils c c produce ! poles n s1 z %[n 9 ,fig4 #b;a4 ,! result+ pol>ity is indicat$ by ! lett]s ,n ,s1 & x w be obs]v$ t ! poles ( ! r+ h be5 %ift$ "o-eigh? ( ! p]iph]y ( ! same4 ,illu/ration3 ,,fig4 #d4 ,illu/ration3 ,,fig4 #d;a4 ,9 ,fig4 #c ! armature has complet$ "o qu>t] ( "o revolution4 ,9 ?is phase ! curr5t 9 coil ,c is a maximum1 & ( su* direction z to produce ! poles ,n ,s 9 ,fig4 #c;a1 :]eas ! curr5t 9 coil ,c#a is nil1 ?is coil be+ at its neutral position4 ,! poles ,n ,s 9 ,fig4 #c;a are ?us %ift$ "o qu>t] ( ! circumf]5ce ( ! r+4 ,fig4 #d %[s ! coils ,c ,c 9 a /ill m advanc$ position1 ! armature hav+ complet$ ?ree-eigh?s ( "o revolution4 ,at t mom5t ! coil ,c /ill g5]ates a curr5t ( ! same direction z be=e1 b ( less /r5g?1 produc+ ! comp>atively weak] poles n s 9 ,fig4 #d;a4 ,! curr5t 9 ! coil ,c#a is ( ! same /r5g?1 b opposite direction4 ,its effect is1 !re=e1 to produce ^u ! r+ ! poles n#a s#a1 z indicat$1 & a pol>ity1 ,n ,s1 results1 ! poles n[ be+ %ift$ ?ree-eigh?s ( ! p]iph]y ( ! r+4 ,illu/ration3 ,,fig4 #e4 ,illu/ration3 ,,fig4 #e;a4 ,9 ,fig4 #e "o half ( "o revolution ( ! armature is complet$1 & ! result+ magnetic condition ( ! r+ is indicat$ 9 ,fig4 #e;a4 ,n[ ! curr5t 9 coil ,c is nil1 :ile ! coil ,c#a yields its maximum curr5t1 :i* is ( ! same direction z previ\sly2 ! magnetiz+ effect is1 !re=e1 due to ! coils1 c#a c#a alone1 &1 ref]r+ to ,fig4 #e;a1 x w be obs]v$ t ! poles ,n ,s are %ift$ "o half ( ! circumf]5ce ( ! r+4 ,dur+ ! next half revolution ! op]ations are repeat$1 z repres5t$ 9 ! ,figs4 #f to #h;a4 ,illu/ration3 ,,fig4 #f4 ,illu/ration3 ,,fig4 #f;a4 ,a ref]5ce to ! diagrams w make x cle> t dur+ "o revolution ( ! armature ! poles ( ! r+ are %ift$ once ar\nd its p]iph]y1 &1 ea* revolution produc+ l effects1 a rapid :irl+ ( ! poles 9 h>mony ) ! rotation ( ! armature is ! result4 ,if ! connections ( ei!r "o ( ! circuits 9 ! r+ are rev]s$1 ! %ift+ ( ! poles is made to progress 9 ! opposite direction1 b ! op]ation is id5tically ! same4 ,in/ead ( us+ f\r wires1 ) l result1 ?ree wires may be us$1 "o =m+ a common return = bo? circuits4 ,illu/ration3 ,,fig4 #g4 ,illu/ration3 ,,fig4 #g;a4 ,?is rotation or :irl+ ( ! poles manife/s itself 9 a s]ies ( curi\s ph5om5a4 ,if a delicately pivot$ disc ( /eel or o!r magnetic metal is approa*$ to ! r+ x is set 9 rapid rotation1 ! direction ( rotation v>y+ ) ! position ( ! disc4 ,= in/ance1 not+ ! direction outside ( ! r+ x w be f\nd t inside ! r+ x turns 9 an opposite direction1 :ile x is unaffect$ if plac$ 9 a position symmetrical to ! r+4 ,?is is easily expla9$4 ,ea* "t t a pole approa*es1 x induces an opposite pole 9 ! ne>e/ po9t on ! disc1 & an attraction is produc$ ^u t po9t2 ow+ to ?is1 z ! pole is %ift$ fur!r away f ! disc a tang5tial pull is ex]t$ ^u ! same1 & ! action be+ con/antly repeat$1 a m or less rapid rotation ( ! disc is ! result4 ,z ! pull is ex]t$ ma9ly ^u t "p :i* is ne>e/ to ! r+1 ! rotation outside & inside1 or "r & left1 respectively1 is 9 opposite directions1 ,fig4 #i4 ,:5 plac$ symmetrically to ! r+1 ! pull on ! opposite sides ( ! disc be+ equal1 no rotation results4 ,! action is bas$ on ! magnetic in]tia ( iron2 = ?is reason a disc ( h>d /eel is mu* m affect$ ?an a disc ( s(t iron1 ! latt] be+ capable ( v rapid v>iations ( magnetism4 ,su* a disc has prov$ to be a v useful in/rum5t 9 all ^! inve/igations1 z x has enabl$ me to detect any irregul>ity 9 ! action4 ,a curi\s effect is also produc$ ^u iron fil+s4 ,by plac+ "s ^u a pap] & hold+ !m ext]nally q close to ! r+1 !y are set 9 a vibrat+ motion1 rema9+ 9 ! same place1 al?\gh ! pap] may be mov$ back & =?2 b 9 lift+ ! pap] to a c]ta9 height :i* seems to be dep5d5t on ! int5sity ( ! poles & ! spe$ ( rotation1 !y are ?r[n away 9 a direction always opposite to ! suppos$ movem5t ( ! poles4 ,if a pap] ) fil+s is put flat ^u ! r+ & ! curr5t turn$ on sudd5ly1 ! exi/5ce ( a magnetic :irl may easily be obs]v$4 ,to demon/rate ! complete analogy betwe5 ! r+ & a revolv+ magnet1 a /rongly en]giz$ electro-magnet 0 rotat$ by me*anical p[]1 & ph5om5a id5tical 9 e p>ticul> to ^? m5tion$ above 7 obs]v$4 ,obvi\sly1 ! rotation ( ! poles produces correspond+ inductive effects & may be utiliz$ to g5]ate curr5ts 9 a clos$ conductor plac$ )9 ! influ5ce ( ! poles4 ,= ?is purpose x is conv5i5t to w9d a r+ ) two sets ( sup]impos$ coils =m+ respectively ! prim>y & second>y circuits1 z %[n 9 ,fig4 #aj4 ,9 ord] to secure ! mo/ economical results ! magnetic circuit %\ld be completely clos$1 & ) ?is object 9 view ! con/ruction may be modifi$ at w4 ,illu/ration3 ,,fig4 #h4 ,illu/ration3 ,,fig4 #h;a4 ,! inductive effect ex]t$ ^u ! second>y coils w be ma9ly due to ! %ift+ or movem5t ( ! magnetic action2 b !re may also be curr5ts set up 9 ! circuits 9 consequ5ce ( ! v>iations 9 ! int5sity ( ! poles4 ,h[ev]1 by prop]ly design+ ! g5]ator & det]m9+ ! magnetiz+ effect ( ! prim>y coils1 ! latt] elem5t may be made to disappe>4 ,! int5sity ( ! poles be+ ma9ta9$ con/ant1 ! action ( ! app>atus w be p]fect1 & ! same result w be secur$ z ?\gh ! %ift+ 7 effect$ by means ( a commutator ) an inf9ite numb] ( b>s4 ,9 su* case ! !oretical relation betwe5 ! en]giz+ effect ( ea* set ( prim>y coils & _! resultant magnetiz+ effect may be express$ by ! equation ( a circle hav+ its c5tre co9cid+ ) t ( an or?ogonal sy/em ( axes1 & 9 :i* ! radius repres5ts ! resultant & ! co-ord9ates bo? ( its compon5ts4 ,^! are !n respectively ! s9e & cos9e ( ! angle a betwe5 ! radius & "o ( ! axes 7,,ox74 ,ref]r+ to ,fig4 #aa1 we h r#b x#b y#b2 :]e x r cos a1 & y r s9 a4 ,assum+ ! magnetiz+ effect ( ea* set ( coils 9 ! trans=m] to be proportional to ! curr5t--:i* may be admitt$ = weak degrees ( magnetization--!n x ,kc & y ,kc#a1 :]e ,k is a con/ant & c & c#a ! curr5t 9 bo? sets ( coils respectively4 ,suppos+1 fur!r1 ! field ( ! g5]ator to be uni=m1 we h = con/ant spe$ c#a ,k#a s9 a & c ,k#a s9 7#ij deg4 a7 ,k#a cos a1 :]e ,k#a is a con/ant4 ,see ,fig4 #ab4 ,!re=e1 x ,kc ,k ,k#a cos a2 y ,kc#a ,k ,k#a s9 a2 & ,k ,k#a r4 ,illu/ration3 ,,fig4 #i4 ,t is1 = a uni=m field ! disposition ( ! two coils at "r angles w secure ! !oretical result1 & ! int5sity ( ! %ift+ poles w be con/ant4 ,b f r#b x#b y#b x foll[s t = y #j1 r x2 x foll[s t ! jo9t magnetiz+ effect ( bo? sets ( coils %\ld be equal to ! effect ( "o set :5 at its maximum action4 ,9 trans=m]s & 9 a c]ta9 class ( motors ! fluctuation ( ! poles is n ( great importance1 b 9 ano!r class ( ^! motors x is desirable to obta9 ! !oretical result4 ,9 apply+ ?is pr9ciple to ! con/ruction ( motors1 two typical =ms ( motor h be5 develop$4 ,fir/1 a =m hav+ a comp>atively small rot>y ef=t at ! />t b ma9ta9+ a p]fectly uni=m spe$ at all loads1 :i* motor has be5 t]m$ syn*ron\s4 ,second1 a =m possess+ a great rot>y ef=t at ! />t1 ! spe$ be+ dep5d5t on ! load4 ,^! motors may be op]at$ 9 ?ree diff]5t ways3 #a4 ,by ! alt]nate curr5ts ( ! s\rce only4 #b4 ,by a comb9$ action ( ^! & ( induc$ curr5ts4 #c4 ,by ! jo9t action ( alt]nate & cont9u\s curr5ts4 ,illu/ration3 ,,fig4 #aj4 ,! simple/ =m ( a syn*ron\s motor is obta9$ by w9d+ a lam9at$ r+ provid$ ) pole projections ) f\r coils1 & connect+ ! same 9 ! mann] be=e indicat$4 ,an iron disc hav+ a segm5t cut away on ea* side may be us$ z an armature4 ,su* a motor is %[n 9 ,fig4 #i4 ,! disc be+ arrang$ to rotate freely )9 ! r+ 9 close proximity to ! projections1 x is evid5t t z ! poles are %ift$ x w1 ow+ to its t5d5cy to place itself 9 su* a position z to embrace ! greate/ numb] ( ! l9es ( =ce1 closely foll[ ! movem5t ( ! poles1 & its motion w be syn*ron\s ) t ( ! armature ( ! g5]ator2 t is1 9 ! peculi> disposition %[n 9 ,fig4 #i1 9 :i* ! armature produces by "o revolution two curr5t impulses 9 ea* ( ! circuits4 ,x is evid5t t if1 by "o revolution ( ! armature1 a great] numb] ( impulses is produc$1 ! spe$ ( ! motor w be correspond+ly increas$4 ,consid]+ t ! attraction ex]t$ ^u ! disc is greate/ :5 ! same is 9 close proximity to ! poles1 x foll[s t su* a motor w ma9ta9 exactly ! same spe$ at all loads )9 ! limits ( its capacity4 ,to facilitate ! />t+1 ! disc may be provid$ ) a coil clos$ ^u itself4 ,! advantage secur$ by su* a coil is evid5t4 ,on ! />t ! curr5ts set up 9 ! coil /rongly en]gize ! disc & increase ! attraction ex]t$ ^u ! same by ! r+1 & curr5ts be+ g5]at$ 9 ! coil z long z ! spe$ ( ! armature is inf]ior to t ( ! poles1 consid]able "w may be p]=m$ by su* a motor ev5 if ! spe$ be bel[ normal4 ,! int5sity ( ! poles be+ con/ant1 no curr5ts w be g5]at$ 9 ! coil :5 ! motor is turn+ at its normal spe$4 ,in/ead ( clos+ ! coil ^u itself1 its ends may be connect$ to two insulat$ slid+ r+s1 & a cont9u\s curr5t suppli$ to ^! f a suitable g5]ator4 ,! prop] way to />t su* a motor is to close ! coil ^u itself until ! normal spe$ is rea*$1 or ne>ly s1 & !n turn on ! cont9u\s curr5t4 ,if ! disc be v /rongly en]giz$ by a cont9u\s curr5t ! motor may n be able to />t1 b if x be weakly en]giz$1 or g5]ally s t ! magnetiz+ effect ( ! r+ is prepond]at+1 x w />t & rea* ! normal spe$4 ,su* a motor w ma9ta9 absolutely ! same spe$ at all loads4 ,x has also be5 f\nd t if ! motive p[] ( ! g5]ator is n excessive1 by *eck+ ! motor ! spe$ ( ! g5]ator is dim9i%$ 9 syn*ronism ) t ( ! motor4 ,x is *>act]i/ic ( ?is =m ( motor t x _c be rev]s$ by rev]s+ ! cont9u\s curr5t ?r\gh ! coil4 ,illu/ration3 ,,fig4 #aa4 ,illu/ration3 ,,fig4 #ab4 ,! syn*ronism ( ^! motors may be demon/rat$ exp]im5tally 9 a v>iety ( ways4 ,= ?is purpose x is be/ to employ a motor consi/+ ( a /ation>y field magnet & an armature arrang$ to rotate )9 ! same1 z indicat$ 9 ,fig4 #ac4 ,9 ?is case ! %ift+ ( ! poles ( ! armature produces a rotation ( ! latt] 9 ! opposite direction4 ,x results !refrom t :5 ! normal spe$ is rea*$1 ! poles ( ! armature assume fix$ positions relatively to ! field magnet1 & ! same is magnetiz$ by induction1 exhibit+ a di/9ct pole on ea* ( ! pole-pieces4 ,if a piece ( s(t iron is approa*$ to ! field magnet1 x w at ! />t be attract$ ) a rapid vibrat+ motion produc$ by ! rev]sals ( pol>ity ( ! magnet1 b z ! spe$ ( ! armature increases1 ! vibrations become less & less frequ5t & f9ally entirely cease4 ,!n ! iron is weakly b p]man5tly attract$1 %[+ t syn*ronism is rea*$ & ! field magnet en]giz$ by induction4 ,! disc may also be us$ = ! exp]im5t4 ,if held q close to ! armature x w turn z long z ! spe$ ( rotation ( ! poles exce$s t ( ! armature2 b :5 ! normal spe$ is rea*$1 or v ne>ly s1 x ceases to rotate & is p]man5tly attract$4 ,illu/ration3 ,,fig4 #ac4 ,a crude b illu/rative exp]im5t is made ) an inc&esc5t lamp4 ,plac+ ! lamp 9 circuit ) ! cont9u\s curr5t g5]ator & 9 s]ies ) ! magnet coil1 rapid fluctuations are obs]v$ 9 ! light 9 consequ5ce ( ! induc$ curr5ts set up 9 ! coil at ! />t2 ! spe$ increas+1 ! fluctuations occur at long] int]vals1 until !y entirely disappe>1 %[+ t ! motor has atta9$ its normal spe$4 ,a telephone receiv] af=ds a mo/ s5sitive in/rum5t2 :5 connect$ to any circuit 9 ! motor ! syn*ronism may be easily detect$ on ! disappe>ance ( ! induc$ curr5ts4 ,9 motors ( ! syn*ron\s type x is desirable to ma9ta9 ! quantity ( ! %ift+ magnetism con/ant1 especially if ! magnets are n prop]ly subdivid$4 ,to obta9 a rot>y ef=t 9 ^! motors 0 ! subject ( long ?\ght4 ,9 ord] to secure ?is result x 0 necess>y to make su* a disposition t :ile ! poles ( "o elem5t ( ! motor are %ift$ by ! alt]nate curr5ts ( ! s\rce1 ! poles produc$ ^u ! o!r elem5ts %\ld always be ma9ta9$ 9 ! prop] relation to ! =m]1 irrespective ( ! spe$ ( ! motor4 ,su* a condition exi/s 9 a cont9u\s curr5t motor2 b 9 a syn*ron\s motor1 su* z describ$1 ?is condition is fulfill$ only :5 ! spe$ is normal4 ,illu/ration3 ,,fig4 #ad4 ,! object has be5 atta9$ by plac+ )9 ! r+ a prop]ly subdivid$ cyl9drical iron core w\nd ) sev]al indep5d5t coils clos$ ^u !mselves4 ,two coils at "r angles z 9 ,fig4 #ad1 are suffici5t1 b a great] numb] may be advantage\sly employ$4 ,x results f ?is disposition t :5 ! poles ( ! r+ are %ift$1 curr5ts are g5]at$ 9 ! clos$ armature coils4 ,^! curr5ts are ! mo/ int5se at or ne> ! po9ts ( ! greate/ d5sity ( ! l9es ( =ce1 & _! effect is to produce poles ^u ! armature at "r angles to ^? ( ! r+1 at lea/ !oretically s2 & s9ce ?is action is entirely indep5d5t ( ! spe$--t is1 z f> z ! location ( ! poles is conc]n$--a cont9u\s pull is ex]t$ ^u ! p]iph]y ( ! armature4 ,9 _m respects ^! motors are simil> to ! cont9u\s curr5t motors4 ,if load is put on1 ! spe$1 & also ! resi/ance ( ! motor1 is dim9i%$ & m curr5t is made to pass ?r\gh ! en]giz+ coils1 ?us increas+ ! ef=t4 ,^u ! load be+ tak5 (f1 ! c\nt]-electromotive =ce increases & less curr5t passes ?r\gh ! prim>y or en]giz+ coils4 ,)\t any load ! spe$ is v ne>ly equal to t ( ! %ift+ poles ( ! field magnet4 ,illu/ration3 ,,fig4 #ae4 ,illu/ration3 ,,fig4 #af4 ,illu/ration3 ,,fig4 #ag4 ,x w be f\nd t ! rot>y ef=t 9 ^! motors fully equals t ( ! cont9u\s curr5t motors4 ,! ef=t seems to be greate/ :5 bo? armature & field magnet are )\t any projections2 b z 9 su* dispositions ! field _c be conc5trat$1 probably ! be/ results w be obta9$ by leav+ pole projections on "o ( ! elem5ts only4 ,g5]ally1 x may be /at$ ! projections dim9i% ! torque & produce a t5d5cy to syn*ronism4 ,a *>act]i/ic feature ( motors ( ?is k9d is _! prop]ty ( be+ v rapidly rev]s$4 ,?is foll[s f ! peculi> action ( ! motor4 ,suppose ! armature to be rotat+ & ! direction ( rotation ( ! poles to be rev]s$4 ,! app>atus !n repres5ts a dynamo ma*9e1 ! p[] to drive ?is ma*9e be+ ! mom5tum /or$ up 9 ! armature & its spe$ be+ ! sum ( ! spe$s ( ! armature & ! poles4 ,illu/ration3 ,,fig4 #ah4 ,illu/ration3 ,,fig4 #ai4 ,illu/ration3 ,,fig4 #bj4 ,illu/ration3 ,,fig4 #ba4 ,if we n[ consid] t ! p[] to drive su* a dynamo w\ld be v ne>ly proportional to ! ?ird p[] ( ! spe$1 = t reason alone ! armature %\ld be quickly rev]s$4 ,b simultane\sly ) ! rev]sal ano!r elem5t is br\ght into action1 namely1 z ! movem5t ( ! poles ) respect to ! armature is rev]s$1 ! motor acts l a trans=m] 9 :i* ! resi/ance ( ! second>y circuit w\ld be abnormally dim9i%$ by produc+ 9 ?is circuit an additional electromotive =ce4 ,ow+ to ^! causes ! rev]sal is in/antane\s4 ,if x is desirable to secure a con/ant spe$1 & at ! same "t a c]ta9 ef=t at ! />t1 ?is result may be easily atta9$ 9 a v>iety ( ways4 ,= in/ance1 two armatures1 "o = torque & ! o!r = syn*ronism1 may be fa/5$ on ! same %aft & any desir$ prepond]ance may be giv5 to ei!r "o1 or an armature may be w\nd = rot>y ef=t1 b a m or less pron\nc$ t5d5cy to syn*ronism may be giv5 to x by prop]ly con/ruct+ ! iron core2 & 9 _m o!r ways4 ,z a means ( obta9+ ! requir$ phase ( ! curr5ts 9 bo? ! circuits1 ! disposition ( ! two coils at "r angles is ! simple/1 secur+ ! mo/ uni=m action2 b ! phase may be obta9$ 9 _m o!r ways1 v>y+ ) ! ma*9e employ$4 ,any ( ! dynamos at pres5t 9 use may be easily adapt$ = ?is purpose by mak+ connections to prop] po9ts ( ! g5]at+ coils4 ,9 clos$ circuit armatures1 su* z us$ 9 ! cont9u\s curr5t sy/ems1 x is be/ to make f\r d]ivations f equi-di/ant po9ts or b>s ( ! commutator1 & to connect ! same to f\r insulat$ slid+ r+s on ! %aft4 ,9 ?is case ea* ( ! motor circuits is connect$ to two diametrically opposite b>s ( ! commutator4 ,9 su* a disposition ! motor may also be op]at$ at half ! pot5tial & on ! ?ree-wire plan1 by connect+ ! motor circuits 9 ! prop] ord] to ?ree ( ! contact r+s4 ,9 multipol> dynamo ma*9es1 su* z us$ 9 ! conv]t] sy/ems1 ! phase is conv5i5tly obta9$ by w9d+ ^u ! armature two s]ies ( coils 9 su* a mann] t :ile ! coils ( "o set or s]ies are at _! maximum production ( curr5t1 ! coils ( ! o!r w be at _! neutral position1 or ne>ly s1 :]eby bo? sets ( coils may be subject$ simultane\sly or successively to ! induc+ action ( ! field magnets4 ,g5]ally ! circuits 9 ! motor w be simil>ly dispos$1 & v>i\s arrangem5ts may be made to fulfill ! requirem5ts2 b ! simple/ & mo/ practicable is to arrange prim>y circuits on /ation>y p>ts ( ! motor1 !reby obviat+1 at lea/ 9 c]ta9 =ms1 ! employm5t ( slid+ contacts4 ,9 su* a case ! magnet coils are connect$ alt]nately 9 bo? ! circuits2 t is1 #a1 #c1 #e 444 9 "o1 & #b1 #d1 #f 444 9 ! o!r1 & ! coils ( ea* set ( s]ies may be connect$ all 9 ! same mann]1 or alt]nately 9 opposition2 9 ! latt] case a motor ) half ! numb] ( poles w result1 & its action w be correspond+ly modifi$4 ,! ,figs4 #ae1 #af1 & #ag1 %[ ?ree diff]5t phases1 ! magnet coils 9 ea* circuit be+ connect$ alt]nately 9 opposition4 ,9 ?is case !re w be always f\r poles1 z 9 ,figs4 #ae & #ag2 f\r pole projections w be neutral2 & 9 ,fig4 #af two adjac5t pole projections w h ! same pol>ity4 ,if ! coils are connect$ 9 ! same mann] !re w be eight alt]nat+ poles1 z indicat$ by ! lett]s n' s' 9 ,fig4 #ae4 ,! employm5t ( multipol> motors secures 9 ?is sy/em an advantage mu* desir$ & unatta9able 9 ! cont9u\s curr5t sy/em1 & t is1 t a motor may be made to run exactly at a pr$et]m9$ spe$ irrespective ( imp]fections 9 con/ruction1 ( ! load1 &1 )9 c]ta9 limits1 ( electromotive =ce & curr5t /r5g?4 ,9 a g5]al di/ribution sy/em ( ?is k9d ! foll[+ plan %\ld be adopt$4 ,at ! c5tral /ation ( supply a g5]ator %\ld be provid$ hav+ a consid]able numb] ( poles4 ,! motors op]at$ f ?is g5]ator %\ld be ( ! syn*ron\s type1 b possess+ suffici5t rot>y ef=t to insure _! />t+4 ,) ! obs]vance ( prop] rules ( con/ruction x may be admitt$ t ! spe$ ( ea* motor w be 9 "s inv]se proportion to its size1 & ! numb] ( poles %\ld be *os5 accord+ly4 ,/ill1 exceptional dem&s may modify ?is rule4 ,9 view ( ?is1 x w be advantage\s to provide ea* motor ) a great] numb] ( pole projections or coils1 ! numb] be+ pref]ably a multiple ( two & ?ree4 ,by ?is means1 by simply *ang+ ! connections ( ! coils1 ! motor may be adapt$ to any probable dem&s4 ,if ! numb] ( ! poles 9 ! motor is ev51 ! action w be h>moni\s & ! prop] result w be obta9$2 if ?is is n ! case1 ! be/ plan to be foll[$ is to make a motor ) a d\ble numb] ( poles & connect ! same 9 ! mann] be=e indicat$1 s t half ! numb] ( poles result4 ,suppose1 = in/ance1 t ! g5]ator has twelve poles1 & x w\ld be desir$ to obta9 a spe$ equal to #ab_/g ( ! spe$ ( ! g5]ator4 ,?is w\ld require a motor ) sev5 pole projections or magnets1 & su* a motor c\ld n be prop]ly connect$ 9 ! circuits unless f\rte5 armature coils w\ld be provid$1 :i* w\ld necessitate ! employm5t ( slid+ contacts4 ,to avoid ?is1 ! motor %\ld be provid$ ) f\rte5 magnets & sev5 connect$ 9 ea* circuit1 ! magnets 9 ea* circuit alt]nat+ among !mselves4 ,! armature %\ld h f\rte5 clos$ coils4 ,! action ( ! motor w n be q z p]fect z 9 ! case ( an ev5 numb] ( poles1 b ! drawback w n be ( a s]i\s nature4 ,h[ev]1 ! disadvantages result+ f ?is unsymmetrical =m w be r$uc$ 9 ! same proportion z ! numb] ( ! poles is augm5t$4 ,if ! g5]ator has1 say1 n1 & ! motor n#a poles1 ! spe$ ( ! motor w be equal to t ( ! g5]ator multipli$ by n_/n#a4 ,! spe$ ( ! motor w g5]ally be dep5d5t on ! numb] ( ! poles1 b !re may be exceptions to ?is rule4 ,! spe$ may be modifi$ by ! phase ( ! curr5ts 9 ! circuit or by ! "* ( ! curr5t impulses or by int]vals betwe5 ea* or betwe5 gr\ps ( impulses4 ,"s ( ! possible cases are indicat$ 9 ! diagrams1 ,figs4 #ah1 #ai1 #bj & #ba1 :i* are self-explanatory4 ,fig4 #ah repres5ts ! condition g5]ally exi/+1 & :i* secures ! be/ result4 ,9 su* a case1 if ! typical =m ( motor illu/rat$ 9 ,fig4 #i is employ$1 "o complete wave 9 ea* circuit w produce "o revolution ( ! motor4 ,9 ,fig4 #ai ! same result w be effect$ by "o wave 9 ea* circuit1 ! impulses be+ successive2 9 ,fig4 #bj by f\r1 & 9 ,fig4 #ba by eight waves4 ,by su* means any desir$ spe$ may be atta9$1 t is1 at lea/ )9 ! limits ( practical dem&s4 ,?is sy/em possesses ?is advantage1 besides o!rs1 result+ f simplicity4 ,at full loads ! motors %[ an effici5cy fully equal to t ( ! cont9u\s curr5t motors4 ,! trans=m]s pres5t an additional advantage 9 _! capability ( op]at+ motors4 ,!y are capable ( simil> modifications 9 con/ruction1 & w facilitate ! introduction ( motors & _! adaptation to practical dem&s4 ,_! effici5cy %\ld be high] ?an t ( ! pres5t trans=m]s1 & ,i base my ass]tion on ! foll[+3 ,9 a trans=m]1 z con/ruct$ at pres5t1 we produce ! curr5ts 9 ! second>y circuit by v>y+ ! /r5g? ( ! prim>y or excit+ curr5ts4 ,if we admit proportionality ) respect to ! iron core ! inductive effect ex]t$ ^u ! second>y coil w be proportional to ! num]ical sum ( ! v>iations 9 ! /r5g? ( ! excit+ curr5t p] unit ( "t2 :5ce x foll[s t = a giv5 v>iation any prolongation ( ! prim>y curr5t w result 9 a proportional loss4 ,9 ord] to obta9 rapid v>iations 9 ! /r5g? ( ! curr5t1 ess5tial to effici5t induction1 a great numb] ( undulations are employ$2 f ?is practice v>i\s disadvantages result4 ,^! are3 ,increas$ co/ & dim9i%$ effici5cy ( ! g5]ator2 m wa/e ( en]gy 9 heat+ ! cores1 & also dim9i%$ output ( ! trans=m]1 s9ce ! core is n prop]ly utiliz$1 ! rev]sals be+ too rapid4 ,! inductive effect is also v small 9 c]ta9 phases1 z w be app>5t f a graphic repres5tation1 & !re may be p]iods ( inaction1 if !re are int]vals betwe5 ! succe$+ curr5t impulses or waves4 ,9 produc+ a %ift+ ( ! poles 9 a trans=m]1 & !reby induc+ curr5ts1 ! induction is ( ! ideal "*1 be+ always ma9ta9$ at its maximum action4 ,x is also reasonable to assume t by a %ift+ ( ! poles less en]gy w be wa/$ ?an by rev]sals4 ,,*apt] ,,iv4 ,,modifications ,,& ,,expansions ,,( ,,! ,,tesla ,,polyphase ,,sy/ems4 ,9 8 e>li] pap]s & pat5ts relative to polyphase curr5ts1 ,mr4 ,tesla devot$ himself *iefly to an enunciation ( ! broad l9es & ideas ly+ at ! basis ( ?is new "w2 b he supplem5t$ ?is imm$iately by a s]ies ( o!r /rik+ inv5tions :i* may be reg>d$ z modifications & expansions ( c]ta9 features ( ! ,tesla sy/ems4 ,^! we %all n[ proce$ to deal )4 ,9 ! prec$+ *apt]s we h ?us %[n & describ$ ! ,tesla electrical sy/ems = ! transmission ( p[] & ! conv]sion & di/ribution ( electrical en]gy1 9 :i* ! motors & ! trans=m]s conta9 two or m coils or sets ( coils1 :i* 7 connect$ up 9 indep5d5t circuits ) correspond+ coils ( an alt]nat+ curr5t g5]ator1 ! op]ation ( ! sy/em be+ br\ght ab\t by ! co-op]ation ( ! alt]nat+ curr5ts 9 ! indep5d5t circuits 9 progressively mov+ or %ift+ ! poles or po9ts ( maximum magnetic effect ( ! motors or conv]t]s4 ,9 ^! sy/ems two indep5d5t conductors are employ$ = ea* ( ! indep5d5t circuits connect+ ! g5]ator ) ! devices = conv]t+ ! transmitt$ curr5ts into me*anical en]gy or into electric curr5ts ( ano!r "*4 ,?is1 h[ev]1 is n always necess>y4 ,! two or m circuits may h a s+le return pa? or wire 9 common1 ) a loss1 if any1 :i* is s extremely slight t x may be disreg>d$ entirely4 ,= ! sake ( illu/ration1 if ! g5]ator h two indep5d5t coils & ! motor two coils or two sets ( coils 9 correspond+ relations to its op]ative elem5ts "o t]m9al ( ea* g5]ator coil is connect$ to ! correspond+ t]m9als ( ! motor coils ?r\gh two indep5d5t conductors1 :ile ! opposite t]m9als ( ! respective coils are bo? connect$ to "o return wire4 ,! foll[+ description deals ) ! modification4 ,fig4 #bb is a diagrammatic illu/ration ( a g5]ator & s+le motor con/ruct$ & electrically connect$ 9 accordance ) ! inv5tion4 ,fig4 #bc is a diagram ( ! sy/em z x is us$ 9 op]at+ motors or conv]t]s1 or bo?1 9 p>allel1 :ile ,fig4 #bd illu/rates diagrammatically ! mann] ( op]at+ two or m motors or conv]t]s1 or bo?1 9 s]ies4 ,ref]r+ to ,fig4 #bb1 ,a ,a designate ! poles ( ! field magnets ( an alt]nat+-curr5t g5]ator1 ! armature ( :i*1 be+ 9 ?is case cyl9drical 9 =m & m\nt$ on a %aft1 ,c1 is w\nd longitud9ally ) coils ,b ,b'4 ,! %aft ,c c>ries ?ree insulat$ contact-r+s1 a b c1 to two ( :i*1 z b c1 "o t]m9al ( ea* coil1 z e d1 is connect$4 ,! rema9+ t]m9als1 f g1 are bo? connect$ to ! ?ird r+1 a4 ,illu/ration3 ,,fig4 #bb4 ,illu/ration3 ,,fig4 #bd4 ,a motor 9 ?is case is %[n z compos$ ( a r+1 ,h1 w\nd ) f\r coils1 ,i ,i ,j ,j1 electrically connect$1 s z to co-op]ate 9 pairs1 ) a t5d5cy to fix ! poles ( ! r+ at f\r po9ts n9ety degrees ap>t4 ,)9 ! magnetic r+ ,h is a disc or cyl9drical core w\nd ) two coils1 ,g ,g'1 :i* may be connect$ to =m two clos$ circuits4 ,! t]m9als j k ( ! two sets or pairs ( coils are connect$1 respectively1 to ! b9d+-po/s ,e' ,f'1 & ! o!r t]m9als1 h i1 are connect$ to a s+le b9d+-po/1 ,d'4 ,to op]ate ! motor1 ?ree l9e-wires are us$ to connect ! t]m9als ( ! g5]ator ) ^? ( ! motor4 ,illu/ration3 ,,fig4 #bc4 ,s f> z ! app>5t action or mode ( op]ation ( ?is arrangem5t is conc]n$1 ! s+le wire ,d1 :i* is1 s to speak1 a common return-wire = bo? circuits1 may be reg>d$ z two indep5d5t wires4 ,9 ! illu/ration1 ) ! ord] ( connection %[n1 coil ,b' ( ! g5]ator is produc+ its maximum curr5t & coil ,b its m9imum2 h5ce ! curr5t :i* passes ?r\gh wire e1 r+ b1 bru% b'1 l9e-wire ,e1 t]m9al ,e'1 wire j1 coils ,i ,i1 wire or t]m9al ,d'1 l9e-wire ,d1 bru% a'1 r+ a1 & wire f1 fixes ! pol> l9e ( ! motor midway betwe5 ! two coils ,i ,i2 b z ! coil ,b' moves f ! position indicat$ x g5]ates less curr5t1 :ile coil ,b1 mov+ into ! field1 g5]ates m4 ,! curr5t f coil ,b passes ?r\gh ! devices & wires designat$ by ! lett]s d1 c1 ,c' ,f1 ,f' k1 ,j ,j1 i1 ,d'1 ,d1 a'1 a1 & g1 & ! position ( ! poles ( ! motor w be due to ! resultant effect ( ! curr5ts 9 ! two sets ( coils--t is1 x w be advanc$ 9 proportion to ! advance or =w>d movem5t ( ! armature coils4 ,! movem5t ( ! g5]ator-armature ?r\gh "o-qu>t] ( a revolution w obvi\sly br+ coil ,b' into its neutral position & coil ,b into its position ( maximum effect1 & ?is %ifts ! poles n9ety degrees1 z !y are fix$ solely by coils ,b4 ,?is action is repeat$ = ea* qu>t] ( a complete revolution4 ,:5 m ?an "o motor or o!r device is employ$1 !y may be run ei!r 9 p>allel or s]ies4 ,9 ,fig4 #bc ! =m] arrangem5t is %[n4 ,! electrical device is %[n z a conv]t]1 ,l1 ( :i* ! two sets ( prim>y coils p r are connect$1 respectively1 to ! ma9s ,f ,e1 :i* are electrically connect$ ) ! two coils ( ! g5]ator4 ,! cross-circuit wires l m1 mak+ ^! connections1 are !n connect$ to ! common return-wire ,d4 ,! second>y coils p' p'' are 9 circuits n o1 includ+1 = example1 inc&esc5t lamps4 ,only "o conv]t] is %[n entire 9 ?is figure1 ! o!rs be+ illu/rat$ diagrammatically4 ,:5 motors or conv]t]s are to be run 9 s]ies1 ! two wires ,e ,f are l$ f ! g5]ator to ! coils ( ! fir/ motor or conv]t]1 !n cont9u$ on to ! next1 & s on ?r\gh ! :ole s]ies1 & are !n jo9$ to ! s+le wire ,d1 :i* completes bo? circuits ?r\gh ! g5]ator4 ,?is is %[n 9 ,fig4 #bd1 9 :i* ,j ,i repres5t ! two coils or sets ( coils ( ! motors4 ,!re are1 ( c\rse1 o!r conditions "u :i* ! same idea may be c>ri$ out4 ,= example1 9 case ! motor & g5]ator ea* has ?ree indep5d5t circuits1 "o t]m9al ( ea* circuit is connect$ to a l9e-wire1 & ! o!r ?ree t]m9als to a common return-conductor4 ,?is arrangem5t w secure simil> results to ^? atta9$ ) a g5]ator & motor hav+ b two indep5d5t circuits1 z above describ$4 ,:5 appli$ to su* ma*9es & motors z h ?ree or m induc$ circuits ) a common electrical jo9t1 ! ?ree or m t]m9als ( ! g5]ator w\ld be simply connect$ to ^? ( ! motor4 ,mr4 ,tesla /ates1 h[ev]1 t ! results obta9$ 9 ?is mann] %[ a l[] effici5cy ?an d ! =ms dwelt ^u m fully above4 ,,*apt] ,v4 ,,utiliz+ ,,famili> ,,types ,,( ,,g5]ator ,,( ,,! ,,cont9u\s ,,curr5t ,,type4 ,! prec$+ descriptions h assum$ ! use ( alt]nat+ curr5t g5]ators 9 :i*1 9 ord] to produce ! progressive movem5t ( ! magnetic poles1 or ( ! resultant attraction ( indep5d5t field magnets1 ! curr5t g5]at+ coils are indep5d5t or sep>ate4 ,! ord9>y =ms ( cont9u\s curr5t dynamos may1 h[ev]1 be employ$ = ! same "w1 9 accordance ) a me?od ( adaptation devis$ by ,mr4 ,tesla4 ,z w be se51 ! modification involves b slight *anges 9 _! con/ruction1 & pres5ts o!r elem5ts ( economy4 ,on ! %aft ( a giv5 g5]ator1 ei!r 9 place ( or 9 addition to ! regul> commutator1 are secur$ z _m pairs ( insulat$ collect+-r+s z !re are circuits to be op]at$4 ,n[1 x w be und]/ood t 9 ! op]ation ( any dynamo electric g5]ator ! curr5ts 9 ! coils 9 _! movem5t ?r\gh ! field ( =ce und]go diff]5t phases--t is to say1 at diff]5t positions ( ! coils ! curr5ts h c]ta9 directions & c]ta9 /r5g?s--& t 9 ! ,tesla motors or trans=m]s x is necess>y t ! curr5ts 9 ! en]giz+ coils %\ld und]go a c]ta9 ord] ( v>iations 9 /r5g? & direction4 ,h5ce1 ! fur!r /ep--viz41 ! connection betwe5 ! induc$ or g5]at+ coils ( ! ma*9e & ! contact-r+s f :i* ! curr5ts are to be tak5 (f--w be det]m9$ solely by :at ord] ( v>iations ( /r5g? & direction 9 ! curr5ts is desir$ = produc+ a giv5 result 9 ! electrical translat+ device4 ,?is may be accompli%$ 9 v>i\s ways2 b 9 ! draw+s we give typical in/ances only ( ! be/ & mo/ practicable ways ( apply+ ! inv5tion to ?ree ( ! lead+ types ( ma*9es 9 widespread use1 9 ord] to illu/rate ! pr9ciple4 ,fig4 #be is a diagram illu/rative ( ! mode ( apply+ ! inv5tion to ! well-kn[n type ( clos$ or cont9u\s circuit ma*9es4 ,fig4 #bf is a simil> diagram embody+ an armature ) sep>ate coils connect$ diametrically1 or :at is g5]ally call$ an op5-circuit ma*9e4 ,fig4 #bg is a diagram %[+ ! application ( ! inv5tion to a ma*9e ! armature-coils ( :i* h a common jo9t4 ,illu/ration3 ,,fig4 #be4 ,ref]r+ to ,fig4 #be1 let ,a repres5t a ,tesla motor or trans=m] :i*1 = conv5i5ce1 we w designate z a conv]t]4 ,x consi/s ( an annul> core1 ,b1 w\nd ) f\r indep5d5t coils1 ,c & ,d1 ^? diametrically opposite be+ connect$ toge!r s z to co-op]ate 9 pairs 9 e/abli%+ free poles 9 ! r+1 ! t5d5cy ( ea* pair be+ to fix ! poles at n9ety degrees f ! o!r4 ,!re may be an armature1 ,e1 )9 ! r+1 :i* is w\nd ) coils clos$ ^u !mselves4 ,! object is to pass ?r\gh coils ,c ,d curr5ts ( su* relative /r5g? & direction z to produce a progressive %ift+ or movem5t ( ! po9ts ( maximum magnetic effect ar\nd ! r+1 & to !reby ma9ta9 a rot>y movem5t ( ! armature4 ,!re are !re=e secur$ to ! %aft ,f ( ! g5]ator1 f\r insulat$ contact-r+s1 a b c d1 ^u :i* be> ! collect+-bru%es a' b' c' d'1 connect$ by wires ,g ,g ,h ,h1 respectively1 ) ! t]m9als ( coils ,c & ,d4 ,assume1 = sake ( illu/ration1 t ! coils ,d ,d are to receive ! maximum & coils ,c ,c at ! same in/ant ! m9imum curr5t1 s t ! pol> l9e may be midway betwe5 ! coils ,d ,d4 ,! r+s a b w\ld !re=e be connect$ to ! cont9u\s armature-coil at its neutral po9ts ) respect to ! field1 or ! po9t correspond+ ) t ( ! ord9>y commutator bru%es1 & betwe5 :i* exi/s ! greate/ diff]5ce ( pot5tial2 :ile r+s c d w\ld be connect$ to two po9ts 9 ! coil1 betwe5 :i* exi/s no diff]5ce ( pot5tial4 ,! be/ results w be obta9$ by mak+ ^! connections at po9ts equidi/ant f "o ano!r1 z %[n4 ,^! connections are easie/ made by us+ wires ,l betwe5 ! r+s & ! loops or wires ,j1 connect+ ! coil ,i to ! segm5ts ( ! commutator ,k4 ,:5 ! conv]t]s are made 9 ?is mann]1 x is evid5t t ! phases ( ! curr5ts 9 ! sections ( ! g5]ator coil w be reproduc$ 9 ! conv]t] coils4 ,= example1 aft] turn+ ?r\gh an arc ( n9ety degrees ! conductors ,l ,l1 :i* be=e convey$ ! maximum curr5t1 w receive ! m9imum curr5t by reason ( ! *ange 9 ! position ( _! coils1 & x is evid5t t = ! same reason ! curr5t 9 ^! coils has gradually fall5 f ! maximum to ! m9imum 9 pass+ ?r\gh ! arc ( n9ety degrees4 ,9 ?is special plan ( connections1 ! rotation ( ! magnetic poles ( ! conv]t] w be syn*ron\s ) t ( ! armature coils ( ! g5]ator1 & ! result w be ! same1 :e!r ! en]giz+ circuits are d]ivations f a cont9u\s armature coil or f indep5d5t coils1 z 9 ,mr4 ,tesla's o!r devices4 ,9 ,fig4 #be1 ! bru%es ,m ,m are %[n 9 dott$ l9es 9 _! prop] normal position4 ,9 practice ^! bru%es may be remov$ f ! commutator & ! field ( ! g5]ator excit$ by an ext]nal s\rce ( curr5t2 or ! bru%es may be all[$ to rema9 on ! commutator & to take (f a conv]t$ curr5t to excite ! field1 or to be us$ = o!r purposes4 ,9 a c]ta9 well-kn[n class ( ma*9es kn[n z ! op5 circuit1 ! armature conta9s a numb] ( coils ! t]m9als ( :i* connect to commutator segm5ts1 ! coils be+ connect$ across ! armature 9 pairs4 ,?is type ( ma*9e is repres5t$ 9 ,fig4 #bf4 ,9 ?is ma*9e ea* pair ( coils goes ?r\gh ! same phases z ! coils 9 "s ( ! g5]ators already %[n1 & x is obvi\sly only necess>y to utilize !m 9 pairs or sets to op]ate a ,tesla conv]t] by ext5d+ ! segm5ts ( ! commutators belong+ to ea* pair ( coils & caus+ a collect+ bru% to be> on ! cont9u\s portion ( ea* segm5t4 ,9 ?is way two or m circuits may be tak5 (f f ! g5]ator1 ea* includ+ "o or m pairs or sets ( coils z may be desir$4 ,illu/ration3 ,,fig4 #bf4 ,illu/ration3 ,,fig4 #bg4 ,9 ,fig4 #bf ,i ,i repres5t ! armature coils1 ,t ,t ! poles ( ! field magnet1 & ,f ! %aft c>ry+ ! commutators1 :i* are ext5d$ to =m cont9u\s portions a b c d4 ,! bru%es be>+ on ! cont9u\s portions = tak+ (f ! alt]nat+ curr5ts are repres5t$ by a' b' c' d'4 ,! collect+ bru%es1 or ^? :i* may be us$ to take (f ! direct curr5t1 are designat$ by ,m ,m4 ,two pairs ( ! armature coils & _! commutators are %[n 9 ! figure z be+ utiliz$2 b all may be utiliz$ 9 a simil> mann]4 ,!re is ano!r well-kn[n type ( ma*9e 9 :i* ?ree or m coils1 ,a' ,b' ,c'1 on ! armature h a common jo9t1 ! free ends be+ connect$ to ! segm5ts ( a commutator4 ,?is =m ( g5]ator is illu/rat$ 9 ,fig4 #bg4 ,9 ?is case ea* t]m9al ( ! g5]ator is connect$ directly or 9 d]ivation to a cont9u\s r+1 a b c1 & collect+ bru%es1 a' b' c'1 be>+ !reon1 take (f ! alt]nat+ curr5ts t op]ate ! motor4 ,x is pref]able 9 ?is case to employ a motor or trans=m] ) ?ree en]giz+ coils1 ,a'' ,b'' ,c''1 plac$ symmetrically ) ^? ( ! g5]ator1 & ! circuits f ! latt] are connect$ to ! t]m9als ( su* coils ei!r directly--z :5 !y are /ation>y--or by means ( bru%es e' & contact r+s e4 ,9 ?is1 z 9 ! o!r cases1 ! ord9>y commutator may be us$ on ! g5]ator1 & ! curr5t tak5 f x utiliz$ = excit+ ! g5]ator field-magnets or = o!r purposes4 ,,*apt] ,,vi4 ,,me?od ,,( ,,obta9+ ,,desir$ ,,spe$ ,,( ,,motor ,,or ,,g5]ator4 ,) ! object ( obta9+ ! desir$ spe$ 9 motors op]at$ by means ( alt]nat+ curr5ts ( diff]+ phase1 ,mr4 ,tesla has devis$ v>i\s plans int5d$ to meet ! practical requirem5ts ( ! case1 9 adapt+ 8 sy/em to types ( multipol> alt]nat+ curr5t ma*9es yield+ a l>ge numb] ( curr5t rev]sals = ea* revolution4 ,= example1 ,mr4 ,tesla has po9t$ out t to adapt a giv5 type ( alt]nat+ curr5t g5]ator1 y may c\ple rigidly two complete ma*9es1 secur+ !m toge!r 9 su* a way t ! requisite diff]5ce 9 phase w be produc$2 or y may fa/5 two armatures to ! same %aft )9 ! influ5ce ( ! same field & ) ! requisite angul> displacem5t to yield ! prop] diff]5ce 9 phase betwe5 ! two curr5ts2 or two armatures may be atta*$ to ! same %aft ) _! coils symmetrically dispos$1 b subject to ! influ5ce ( two sets ( field magnets duly displac$2 or ! two sets ( coils may be w\nd on ! same armature alt]nately or 9 su* mann] t !y w develop curr5ts ! phases ( :i* diff] 9 "t suffici5tly to produce ! rotation ( ! motor4 ,ano!r me?od includ$ 9 ! scope ( ! same idea1 :]eby a s+le g5]ator may run a numb] ( motors ei!r at its own rate ( spe$ or all at diff]5t spe$s1 is to con/ruct ! motors ) few] poles ?an ! g5]ator1 9 :i* case _! spe$ w be great] ?an t ( ! g5]ator1 ! rate ( spe$ be+ high] z ! numb] ( _! poles is relatively less4 ,?is may be und]/ood f an example1 tak+ a g5]ator t has two indep5d5t g5]at+ coils :i* revolve betwe5 two pole pieces oppositely magnetiz$2 & a motor ) en]giz+ coils t produce at any giv5 "t two magnetic poles 9 "o elem5t t t5d to set up a rotation ( ! motor4 ,a g5]ator ?us con/ruct$ yields f\r rev]sals1 or impulses1 9 ea* revolution1 two 9 ea* ( its indep5d5t circuits2 & ! effect ^u ! motor is to %ift ! magnetic poles ?r\gh ?ree hundr$ & sixty degrees4 ,x is obvi\s t if ! f\r rev]sals 9 ! same ord] c\ld be produc$ by ea* half-revolution ( ! g5]ator ! motor w\ld make two revolutions to ! g5]ator's "o4 ,?is w\ld be readily accompli%$ by add+ two int]m$iate poles to ! g5]ator or alt]+ x 9 any ( ! o!r equival5t ways above indicat$4 ,! same rule applies to g5]ators & motors ) multiple poles4 ,= in/ance1 if a g5]ator be con/ruct$ ) two circuits1 ea* ( :i* produces twelve rev]sals ( curr5t to a revolution1 & ^! curr5ts be direct$ ?r\gh ! indep5d5t en]giz+-coils ( a motor1 ! coils ( :i* are s appli$ z to produce twelve magnetic poles at all times1 ! rotation ( ! two w be syn*ron\s2 b if ! motor-coils produce b six poles1 ! movable elem5t w be rotat$ twice :ile ! g5]ator rotates once2 or if ! motor h f\r poles1 its rotation w be ?ree times z fa/ z t ( ! g5]ator4 ,illu/ration3 ,,fig4 #bh4 ,illu/ration3 ,,fig4 #bi4 ,^! features1 s f> z necess>y to an und]/&+ ( ! pr9ciple1 are "h illu/rat$4 ,fig4 #bh is a diagrammatic illu/ration ( a g5]ator con/ruct$ 9 accordance ) ! inv5tion4 ,fig4 #bi is a simil> view ( a correspond+ly con/ruct$ motor4 ,fig4 #cj is a diagram ( a g5]ator ( modifi$ con/ruction4 ,fig4 #ca is a diagram ( a motor ( correspond+ "*4 ,fig4 #cb is a diagram ( a sy/em conta9+ a g5]ator & sev]al motors adapt$ to run at v>i\s spe$s4 ,9 ,fig4 #bh1 let ,c repres5t a cyl9drical armature core w\nd longitud9ally ) insulat$ coils ,a ,a1 :i* are connect$ up 9 s]ies1 ! t]m9als ( ! s]ies be+ connect$ to collect+-r+s a a on ! %aft ,g4 ,by means ( ?is %aft ! armature is m\nt$ to rotate betwe5 ! poles ( an annul> field-magnet ,d1 =m$ ) pol> projections w\nd ) coils ,e1 t magnetize ! said projections4 ,! coils ,e are includ$ 9 ! circuit ( a g5]ator ,f1 by means ( :i* ! field-magnet is en]giz$4 ,if ?us con/ruct$1 ! ma*9e is a well-kn[n =m ( alt]nat+-curr5t g5]ator4 ,to adapt x to 8 sy/em1 h[ev]1 ,mr4 ,tesla w9ds on armature ,c a second set ( coils ,b ,b int]m$iate to ! fir/1 or1 9 o!r words1 9 su* positions t :ile ! coils ( "o set are 9 ! relative positions to ! poles ( ! field-magnet to produce ! maximum curr5t1 ^? ( ! o!r set w be 9 ! position 9 :i* !y produce ! m9imum curr5t4 ,! coils ,b are connect$1 also1 9 s]ies & to two connect+-r+s1 secur$ g5]ally to ! %aft at ! opposite end ( ! armature4 ,illu/ration3 ,,fig4 #cj4 ,illu/ration3 ,,fig4 #ca4 ,! motor %[n 9 ,fig4 #bi has an annul> field-magnet ,h1 ) f\r pole-pieces w\nd ) coils ,i4 ,! armature is con/ruct$ simil>ly to ! g5]ator1 b ) two sets ( two coils 9 clos$ circuits to correspond ) ! r$uc$ numb] ( magnetic poles 9 ! field4 ,f ! =ego+ x is evid5t t "o revolution ( ! armature ( ! g5]ator produc+ eight curr5t impulses 9 ea* circuit w produce two revolutions ( ! motor-armature4 ,! application ( ! pr9ciple ( ?is inv5tion is n1 h[ev]1 conf9$ to any p>ticul> =m ( ma*9e4 ,9 ,figs4 #cj & #ca a g5]ator & motor ( ano!r well-kn[n type are %[n4 ,9 ,fig4 #cj1 ,j ,j are magnets dispos$ 9 a circle & w\nd ) coils ,k1 :i* are 9 circuit ) a g5]ator :i* supplies ! curr5t t ma9ta9s ! field ( =ce4 ,9 ! usual con/ruction ( ^! ma*9es ! armature-conductor ,l is c>ri$ by a suitable frame1 s z to be rotat$ 9 face ( ! magnets ,j ,j1 or betwe5 ^! magnets & ano!r simil> set 9 front ( !m4 ,! magnets are en]giz$ s z to be ( alt]nately opposite pol>ity ?r\gh\t ! s]ies1 s t z ! conductor ,c is rotat$ ! curr5t impulses comb9e or are add$ to "o ano!r1 ^? produc$ by ! conductor 9 any giv5 position be+ all 9 ! same direction4 ,to adapt su* a ma*9e to 8 sy/em1 ,mr4 ,tesla adds a second set ( induc$ conductors ,m1 9 all respects simil> to ! fir/1 b s plac$ 9 ref]5ce to x t ! curr5ts produc$ 9 ea* w diff] by a qu>t]-phase4 ,) su* relations x is evid5t t z ! curr5t decreases 9 conductor ,l x increases 9 conductor ,m1 & conv]sely1 & t any ( ! =ms ( ,tesla motor inv5t$ = use 9 ?is sy/em may be op]at$ by su* a g5]ator4 ,fig4 #ca is int5d$ to %[ a motor correspond+ to ! ma*9e 9 ,fig4 #cj4 ,! con/ruction ( ! motor is id5tical ) t ( ! g5]ator1 & if c\pl$ !reto x w run syn*ron\sly !re)4 ,j' ,j' are ! field-magnets1 & ,k' ! coils !reon4 ,l' is "o ( ! armature-conductors & ,m' ! o!r4 ,fig4 #cb %[s 9 diagram o!r =ms ( ma*9e4 ,! g5]ator ,n 9 ?is case is %[n z consi/+ ( a /ation>y r+ ,o1 w\nd ) tw5ty-f\r coils ,p ,p'1 alt]nate coils be+ connect$ 9 s]ies 9 two circuits4 ,)9 ?is r+ is a disc or drum ,q1 ) projections ,q' w\nd ) en]giz+-coils includ$ 9 circuit ) a g5]ator ,r4 ,by driv+ ?is disc or cyl9d] alt]nat+ curr5ts are produc$ 9 ! coils ,p & ,p'1 :i* are c>ri$ (f to run ! sev]al motors4 ,! motors are compos$ ( a r+ or annul> field-magnet ,s1 w\nd ) two sets ( en]giz+-coils ,t ,t'1 & armatures ,u1 hav+ projections ,u' w\nd ) coils ,v1 all connect$ 9 s]ies 9 a clos$ circuit or ea* clos$ indep5d5tly on itself4 ,suppose ! twelve g5]ator-coils ,p are w\nd alt]nately 9 opposite directions1 s t any two adjac5t coils ( ! same set t5d to produce a free pole 9 ! r+ ,o betwe5 !m & ! twelve coils ,p' to be simil>ly w\nd4 ,a s+le revolution ( ! disc or cyl9d] ,q1 ! twelve pol> projections ( :i* are ( opposite pol>ity1 w !re=e produce twelve curr5t impulses 9 ea* ( ! circuits ,w ,w'4 ,h5ce ! motor ,x1 :i* has sixte5 coils or eight free poles1 w make "o & a half turns to ! g5]ator's "o4 ,! motor ,y1 ) twelve coils or six poles1 w rotate ) twice ! spe$ ( ! g5]ator1 & ! motor ,z1 ) eight coils or f\r poles1 w revolve ?ree times z fa/ z ! g5]ator4 ,^! multipol> motors h a peculi>ity :i* may be (t5 utiliz$ to great advantage4 ,= example1 9 ! motor ,x1 ,fig4 #cb1 ! eight poles may be ei!r alt]nately opposite or !re may be at any giv5 "t alt]nately two l & two opposite poles4 ,?is is readily atta9$ by mak+ ! prop] electrical connections4 ,! effect ( su* a *ange1 h[ev]1 w\ld be ! same z r$uc+ ! numb] ( poles "o-half1 & !reby d\bl+ ! spe$ ( any giv5 motor4 ,illu/ration3 ,,fig4 #cb4 ,x is obvi\s t ! ,tesla electrical trans=m]s :i* h indep5d5t prim>y curr5ts may be us$ ) ! g5]ators describ$4 ,x may also be /at$ ) respect to ! devices we n[ describe t ! mo/ p]fect & h>moni\s action ( ! g5]ators & motors is obta9$ :5 ! numb]s ( ! poles ( ea* are ev5 & n odd4 ,if ?is is n ! case1 !re w be a c]ta9 unev5ness ( action :i* is ! less appreciable z ! numb] ( poles is great]2 al?\gh ?is may be 9 a measure correct$ by special provisions :i* x is n "h necess>y to expla94 ,x also foll[s1 z a matt] ( c\rse1 t if ! numb] ( ! poles ( ! motor be great] ?an t ( ! g5]ator ! motor w revolve at a sl[] spe$ ?an ! g5]ator4 ,9 ?is *apt]1 we may include a me?od devis$ by ,mr4 ,tesla = avoid+ ! v high spe$s :i* w\ld be necess>y ) l>ge g5]ators4 ,9 lieu ( revolv+ ! g5]ator armature at a high rate ( spe$1 he secures ! desir$ result by a rotation ( ! magnetic poles ( "o elem5t ( ! g5]ator1 :ile driv+ ! o!r at a diff]5t spe$4 ,! effect is ! same z t yield$ by a v high rate ( rotation4 ,9 ?is in/ance1 ! g5]ator :i* supplies ! curr5t = op]at+ ! motors or trans=m]s consi/s ( a subdivid$ r+ or annul> core w\nd ) f\r diametrically-opposite coils1 ,e ,e'1 ,fig4 #cc4 ,)9 ! r+ is m\nt$ a cyl9drical armature-core w\nd longitud9ally ) two indep5d5t coils1 ,f ,f'1 ! ends ( :i* lead1 respectively1 to two pairs ( insulat$ contact or collect+ r+s1 ,d ,d' ,g ,g'1 on ! armature %aft4 ,collect+ bru%es d d' g g' be> ^u ^! r+s1 respectively1 & convey ! curr5ts ?r\gh ! two indep5d5t l9e-circuits ,m ,m'4 ,9 ! ma9 l9e !re may be includ$ "o or m motors or trans=m]s1 or bo?4 ,if motors be us$1 !y are ( ! usual =m ( ,tesla con/ruction ) indep5d5t coils or sets ( coils ,j ,j'1 includ$1 respectively1 9 ! circuits ,m ,m'4 ,^! en]giz+-coils are w\nd on a r+ or annul> field or on pole pieces !reon1 & produce by ! action ( ! alt]nat+ curr5ts pass+ ?r\gh !m a progressive %ift+ ( ! magnetism f pole to pole4 ,! cyl9drical armature ,h ( ! motor is w\nd ) two coils at "r angles1 :i* =m indep5d5t clos$ circuits4 ,if trans=m]s be employ$1 "o set ( ! prim>y coils1 z ,n ,n1 w\nd on a r+ or annul> core is connect$ to "o circuit1 z ,m'1 & ! o!r prim>y coils1 ,n ,n'1 to ! circuit ,m4 ,! second>y coils ,k ,k' may !n be utiliz$ = runn+ gr\ps ( inc&esc5t lamps ,p ,p'4 ,illu/ration3 ,,fig4 #cc4 ,) ?is g5]ator an excit] is employ$4 ,?is consi/s ( two poles1 ,a ,a1 ( /eel p]man5tly magnetiz$1 or ( iron excit$ by a batt]y or o!r g5]ator ( cont9u\s curr5ts1 & a cyl9drical armature core m\nt$ on a %aft1 ,b1 & w\nd ) two longitud9al coils1 ,c ,c'4 ,"o end ( ea* ( ^! coils is connect$ to ! collect+-r+s b c1 respectively1 :ile ! o!r ends are bo? connect$ to a r+1 a4 ,collect+-bru%es b' c' be> on ! r+s b c1 respectively1 & conductors ,l ,l convey ! curr5ts !refrom ?r\gh ! coils ,e & ,e ( ! g5]ator4 ,l' is a common return-wire to bru% a'4 ,two indep5d5t circuits are ?us =m$1 "o includ+ coils ,c ( ! excit] & ,e ,e ( ! g5]ator1 ! o!r coils ,c' ( ! excit] & ,e' ,e' ( ! g5]ator4 ,x results f ?is t ! op]ation ( ! excit] produces a progressive movem5t ( ! magnetic poles ( ! annul> field-core ( ! g5]ator1 ! %ift+ or rot>y movem5t ( ! poles be+ syn*ron\s ) ! rotation ( ! excit] armature4 ,consid]+ ! op]ative conditions ( a sy/em ?us e/abli%$1 x w be f\nd t :5 ! excit] is driv5 s z to en]gize ! field ( ! g5]ator1 ! armature ( ! latt]1 if left free to turn1 w\ld rotate at a spe$ practically ! same z t ( ! excit]4 ,if "u su* conditions ! coils ,f ,f' ( ! g5]ator armature be clos$ ^u !mselves or %ort-circuit$1 no curr5ts1 at lea/ !oretically1 w be g5]at$ 9 ^! armature coils4 ,9 practice ! pres5ce ( slight curr5ts is obs]v$1 ! exi/5ce ( :i* is attributable to m or less pron\nc$ fluctuations 9 ! int5sity ( ! magnetic poles ( ! g5]ator r+4 ,s1 if ! armature-coils ,f ,f' be clos$ ?r\gh ! motor1 ! latt] w n be turn$ z long z ! movem5t ( ! g5]ator armature is syn*ron\s ) t ( ! excit] or ( ! magnetic poles ( its field4 ,if1 on ! contr>y1 ! spe$ ( ! g5]ator armature be 9 any way *eck$1 s t ! %ift+ or rotation ( ! poles ( ! field becomes relatively m rapid1 curr5ts w be induc$ 9 ! armature coils4 ,?is obvi\sly foll[s f ! pass+ ( ! l9es ( =ce across ! armature conductors4 ,! great] ! spe$ ( rotation ( ! magnetic poles relatively to t ( ! armature ! m rapidly ! curr5ts develop$ 9 ! coils ( ! latt] w foll[ "o ano!r1 & ! m rapidly ! motor w revolve 9 response !reto1 & ?is cont9ues until ! armature g5]ator is /opp$ entirely1 z by a brake1 :5 ! motor1 if prop]ly con/ruct$1 runs at ! spe$ ) :i* ! magnetic poles ( ! g5]ator rotate4 ,! effective /r5g? ( ! curr5ts develop$ 9 ! armature coils ( ! g5]ator is dep5d5t ^u ! /r5g? ( ! curr5ts en]giz+ ! g5]ator & ^u ! numb] ( rotations p] unit ( "t ( ! magnetic poles ( ! g5]ator2 h5ce ! spe$ ( ! motor armature w dep5d 9 all cases ^u ! relative spe$s ( ! armature ( ! g5]ator & ( its magnetic poles4 ,= example1 if ! poles are turn$ two ?\s& times p] unit ( "t & ! armature is turn$ eight hundr$1 ! motor w turn twelve hundr$ times1 or ne>ly s4 ,v slight diff]5ces ( spe$ may be indicat$ by a delicately balanc$ motor4 ,let x n[ be assum$ t p[] is appli$ to ! g5]ator armature to turn x 9 a direction opposite to t 9 :i* its magnetic poles rotate4 ,9 su* case ! result w\ld be simil> to t produc$ by a g5]ator ! armature & field magnets ( :i* are rotat$ 9 opposite directions1 & by reason ( ^! conditions ! motor armature w turn at a rate ( spe$ equal to ! sum ( ! spe$s ( ! armature & magnetic poles ( ! g5]ator1 s t a comp>atively l[ spe$ ( ! g5]ator armature w produce a high spe$ 9 ! motor4 ,x w be obs]v$ 9 connection ) ?is sy/em t on dim9i%+ ! resi/ance ( ! ext]nal circuit ( ! g5]ator armature by *eck+ ! spe$ ( ! motor or by add+ translat+ devices 9 multiple arc 9 ! second>y circuit or circuits ( ! trans=m] ! /r5g? ( ! curr5t 9 ! armature circuit is greatly increas$4 ,?is is due to two causes3 fir/1 to ! great diff]5ces 9 ! spe$s ( ! motor & g5]ator1 &1 secondly1 to ! fact t ! app>atus foll[s ! analogy ( a trans=m]1 =1 9 proportion z ! resi/ance ( ! armature or second>y circuits is r$uc$1 ! /r5g? ( ! curr5ts 9 ! field or prim>y circuits ( ! g5]ator is increas$ & ! curr5ts 9 ! armature are augm5t$ correspond+ly4 ,= simil> reasons ! curr5ts 9 ! armature-coils ( ! g5]ator increase v rapidly :5 ! spe$ ( ! armature is r$uc$ :5 runn+ 9 ! same direction z ! magnetic poles or conv]sely4 ,x w be und]/ood f ! above description t ! g5]ator-armature may be run 9 ! direction ( ! %ift+ ( ! magnetic poles1 b m rapidly1 & t 9 su* case ! spe$ ( ! motor w be equal to ! diff]5ce betwe5 ! two rates4 ,,*apt] ,,vii4 ,,regulator ,,= ,,rot>y ,,curr5t ,,motors4 ,an int]e/+ device = regulat+ & rev]s+ has be5 devis$ by ,mr4 ,tesla = ! purpose ( v>y+ ! spe$ ( polyphase motors4 ,x consi/s ( a =m ( conv]t] or trans=m] ) "o elem5t capable ( movem5t ) respect to ! o!r1 :]eby ! inductive relations may be alt]$1 ei!r manually or automatically1 = ! purpose ( v>y+ ! /r5g? ( ! induc$ curr5t4 ,mr4 ,tesla pref]s to con/ruct ?is device 9 su* mann] t ! induc$ or second>y elem5t may be movable ) respect to ! o!r2 & ! inv5tion1 s f> z relates m]ely to ! con/ruction ( ! device itself1 consi/s1 ess5tially1 9 ! comb9ation1 ) two opposite magnetic poles1 ( an armature w\nd ) an insulat$ coil & m\nt$ on a %aft1 :]eby x may be turn$ to ! desir$ ext5t )9 ! field produc$ by ! poles4 ,! normal position ( ! core ( ! second>y elem5t is t 9 :i* x mo/ completely closes ! magnetic circuit betwe5 ! poles ( ! prim>y elem5t1 & 9 ?is position its coil is 9 its mo/ effective position = ! inductive action ^u x ( ! prim>y coils2 b by turn+ ! movable core to ei!r side1 ! induc$ curr5ts deliv]$ by its coil become weak] until1 by a movem5t ( ! said core & coil ?r\gh #ij deg41 !re w be no curr5t deliv]$4 ,fig4 #cd is a view 9 side elevation ( ! regulator4 ,fig4 #ce is a brok5 section on l9e x x ( ,fig4 #cd4 ,fig4 #cf is a diagram illu/rat+ ! mo/ conv5i5t mann] ( apply+ ! regulator to ord9>y =ms ( motors1 & ,fig4 #cg is a simil> diagram illu/rat+ ! application ( ! device to ! ,tesla alt]nat+-curr5t motors4 ,! regulator may be con/ruct$ 9 _m ways to secure ! desir$ result2 b t :i* is1 p]haps1 its be/ =m is %[n 9 ,figs4 #cd & #ce4 ,a repres5ts a frame ( iron4 ,b ,b are ! cores ( ! induc+ or prim>y coils ,c ,c4 ,d is a %aft m\nt$ on ! side b>s1 ,d'1 & on :i* is secur$ a sectional iron core1 ,e1 w\nd ) an induc$ or second>y coil1 ,f1 ! convolutions ( :i* are p>allel ) ! axis ( ! %aft4 ,! ends ( ! core are r\nd$ (f s z to fit closely 9 ! space betwe5 ! two poles & p]mit ! core ,e to be turn$ to & held at any desir$ po9t4 ,a h&le1 ,g1 secur$ to ! project+ end ( ! %aft ,d1 is provid$ = ?is purpose4 ,illu/ration3 ,,fig4 #cd4 ,illu/ration3 ,,fig4 #ce4 ,9 ,fig4 #cf let ,h repres5t an ord9>y alt]nat+ curr5t g5]ator1 ! field-magnets ( :i* are excit$ by a suitable s\rce ( curr5t1 ,i4 ,let ,j designate an ord9>y =m ( electromagnetic motor provid$ ) an armature1 ,k1 commutator ,l1 & field-magnets ,m4 ,x is well kn[n t su* a motor1 if its field-magnet cores be divid$ up into insulat$ sections1 may be practically op]at$ by an alt]nat+ curr5t2 b 9 us+ ?is regulator ) su* a motor1 ,mr4 ,tesla includes "o elem5t ( ! motor only--say ! armature-coils--9 ! ma9 circuit ( ! g5]ator1 mak+ ! connections ?r\gh ! bru%es & ! commutator 9 ! usual way4 ,he also includes "o ( ! elem5ts ( ! regulator--say ! /ation>y coils--9 ! same circuit1 & 9 ! circuit ) ! second>y or movable coil ( ! regulator he connects up ! field-coils ( ! motor4 ,he also pref]s to use flexible conductors to make ! connections f ! second>y coil ( ! regulator1 z he !reby avoids ! use ( slid+ contacts or r+s )\t int]f]+ ) ! requisite movem5t ( ! core ,e4 ,if ! regulator be 9 its normal position1 or t 9 :i* its magnetic circuit is mo/ ne>ly clos$1 x deliv]s its maximum induc$ curr5t1 ! phases ( :i* s correspond ) ^? ( ! prim>y curr5t t ! motor w run z ?\gh bo? field & armature 7 excit$ by ! ma9 curr5t4 ,illu/ration3 ,,fig4 #cf4 ,to v>y ! spe$ ( ! motor to any rate betwe5 ! m9imum & maximum rates1 ! core ,e & coils ,f are turn$ 9 ei!r direction to an ext5t :i* produces ! desir$ result1 = 9 its normal position ! convolutions ( coil ,f embrace ! maximum numb] ( l9es ( =ce1 all ( :i* act ) ! same effect ^u ! coil2 h5ce x w deliv] its maximum curr5t2 b by turn+ ! coil ,f out ( its position ( maximum effect ! numb] ( l9es ( =ce embrac$ by x is dim9i%$4 ,! inductive effect is !re=e impair$1 & ! curr5t deliv]$ by coil ,f w cont9ue to dim9i% 9 proportion to ! angle at :i* ! coil ,f is turn$ until1 aft] pass+ ?r\gh an angle ( n9ety degrees1 ! convolutions ( ! coil w be at "r angles to ^? ( coils ,c ,c1 & ! inductive effect r$uc$ to a m9imum4 ,incid5tally to c]ta9 con/ructions1 o!r causes may influ5ce ! v>iation 9 ! /r5g? ( ! induc$ curr5ts4 ,= example1 9 ! pres5t case x w be obs]v$ t by ! fir/ movem5t ( coil ,f a c]ta9 portion ( its convolutions are c>ri$ beyond ! l9e ( ! direct influ5ce ( ! l9es ( =ce1 & t ! magnetic pa? or circuit = ! l9es is impair$2 h5ce ! inductive effect w\ld be r$uc$4 ,next1 t aft] mov+ ?r\gh a c]ta9 angle1 :i* is obvi\sly det]m9$ by ! relative dim5sions ( ! bobb9 or coil ,f1 diagonally opposite portions ( ! coil w be simultane\sly includ$ 9 ! field1 b 9 su* positions t ! l9es :i* produce a curr5t-impulse 9 "o portion ( ! coil 9 a c]ta9 direction w produce 9 ! diagonally opposite portion a correspond+ impulse 9 ! opposite direction2 h5ce portions ( ! curr5t w neutralize "o ano!r4 ,z be=e /at$1 ! me*anical con/ruction ( ! device may be greatly v>i$2 b ! ess5tial conditions ( ! pr9ciple w be fulfill$ 9 any app>atus 9 :i* ! movem5t ( ! elem5ts ) respect to "o ano!r effects ! same results by v>y+ ! inductive relations ( ! two elem5ts 9 a mann] simil> to t describ$4 ,illu/ration3 ,,fig4 #cg4 ,x may also be /at$ t ! core ,e is n indisp5sable to ! op]ation ( ! regulator2 b its pres5ce is obvi\sly b5eficial4 ,?is regulator1 h[ev]1 has ano!r valuable prop]ty 9 its capability ( rev]s+ ! motor1 = if ! coil ,f be turn$ ?r\gh a half-revolution1 ! position ( its convolutions relatively to ! two coils ,c ,c & to ! l9es ( =ce is rev]s$1 & consequ5tly ! phases ( ! curr5t w be rev]s$4 ,?is w produce a rotation ( ! motor 9 an opposite direction4 ,?is =m ( regulator is also appli$ ) great advantage to ,mr4 ,tesla's sy/em ( utiliz+ alt]nat+ curr5ts1 9 :i* ! magnetic poles ( ! field ( a motor are progressively %ift$ by means ( ! comb9$ effects ^u ! field ( magnetiz+ coils includ$ 9 indep5d5t circuits1 ?r\gh :i* pass alt]nat+ curr5ts 9 prop] ord] & relations to ea* o!r4 ,9 ,fig4 #cg1 let ,p repres5t a ,tesla g5]ator hav+ two indep5d5t coils1 ,p' & ,p''1 on ! armature1 & ,t a diagram ( a motor hav+ two indep5d5t en]giz+ coils or sets ( coils1 ,r ,r'4 ,"o ( ! circuits f ! g5]ator1 z ,s' ,s'1 includes "o set1 ,r' ,r'1 ( ! en]giz+ coils ( ! motor1 :ile ! o!r circuit1 z ,s ,s1 includes ! prim>y coils ( ! regulator4 ,! second>y coil ( ! regulator includes ! o!r coils1 ,r ,r1 ( ! motor4 ,:ile ! second>y coil ( ! regulator is 9 its normal position1 x produces its maximum curr5t1 & ! maximum rot>y effect is imp>t$ to ! motor2 b ?is effect w be dim9i%$ 9 proportion to ! angle at :i* ! coil ,f ( ! regulator is turn$4 ,! motor w also be rev]s$ by rev]s+ ! position ( ! coil ) ref]5ce to ! coils ,c ,c1 & !reby rev]s+ ! phases ( ! curr5t produc$ by ! g5]ator4 ,?is *anges ! direction ( ! movem5t ( ! %ift+ poles :i* ! armature foll[s4 ,"o ( ! ma9 advantages ( ?is plan ( regulation is its economy ( p[]4 ,:5 ! induc$ coil is g5]at+ its maximum curr5t1 ! maximum am\nt ( en]gy 9 ! prim>y coils is absorb$2 b z ! induc$ coil is turn$ f its normal position ! self-induction ( ! prim>y-coils r$uces ! exp5diture ( en]gy & saves p[]4 ,x is obvi\s t 9 practice ei!r coils ,c ,c or coil ,f may be us$ z prim>y or second>y1 & x is well und]/ood t _! relative proportions may be v>i$ to produce any desir$ diff]5ce or simil>ity 9 ! induc+ & induc$ curr5ts4 ,,*apt] ,,viii4 ,,s+le ,,circuit1 ,,self-,,/>t+ ,,syn*roniz+ ,,motors4 ,9 ! fir/ *apt]s ( ?is section we h1 be>+ 9 m9d ! broad und]ly+ pr9ciple1 consid]$ a di/9ct class ( motors1 namely1 su* z require = _! op]ation a special g5]ator capable ( yield+ curr5ts ( diff]+ phase4 ,z a matt] ( c\rse1 ,mr4 ,tesla recogniz+ ! desirability ( utiliz+ 8 motors 9 connection ) ord9>y sy/ems ( di/ribution1 address$ himself to ! task ( inv5t+ v>i\s me?ods & ways ( a*iev+ ?is object4 ,9 ! succe$+ *apt]s1 !re=e1 we witness ! evolution ( a numb] ( ideas be>+ ^u ?is important bran* ( "w4 ,x mu/ be obvi\s to a c>eful read]1 f a numb] ( h9ts enc\nt]$ "h & !re1 t ev5 ! inv5tions describ$ 9 ^! *apt]s to foll[ d n repres5t ! full scope ( ! "w done 9 ^! l9es4 ,!y might1 inde$1 be reg>d$ z exemplifications4 ,we w pres5t ^! v>i\s inv5tions 9 ! ord] :i* to u appe>s ! mo/ helpful to an und]/&+ ( ! subject by ! majority ( read]s4 ,x w be naturally p]ceiv$ t 9 (f]+ a s]ies ( ideas ( ?is nature1 :]e9 "s ( ! /eps or l9ks are miss+1 ! descriptions are n altoge!r sequ5tial2 b any "o :o foll[s c>efully ! ma9 drift ( ! ?\ghts n[ br\ght toge!r w f9d t a satisfactory compreh5sion ( ! pr9ciples c be ga9$4 ,z is well kn[n1 c]ta9 =ms ( alt]nat+-curr5t ma*9es h ! prop]ty1 :5 connect$ 9 circuit ) an alt]nat+ curr5t g5]ator1 ( runn+ z a motor 9 syn*ronism !re)2 b1 :ile ! alt]nat+ curr5t w run ! motor aft] x has atta9$ a rate ( spe$ syn*ron\s ) t ( ! g5]ator1 x w n />t x4 ,h5ce1 9 all in/ances h]et(ore :]e ^! syn*roniz+ motors1 z !y are t]m$1 h be5 run1 "s means h be5 adopt$ to br+ ! motors up to syn*ronism ) ! g5]ator1 or approximately s1 be=e ! alt]nat+ curr5t ( ! g5]ator is appli$ to drive !m4 ,9 "s in/ances me*anical appliances h be5 utiliz$ = ?is purpose4 ,9 o!rs special & complicat$ =ms ( motor h be5 con/ruct$4 ,mr4 ,tesla has discov]$ a mu* m simple me?od or plan ( op]at+ syn*roniz+ motors1 :i* requires practically no o!r app>atus ?an ! motor itself4 ,9 o!r words1 by a c]ta9 *ange 9 ! circuit connections ( ! motor he conv]ts x at w f a d\ble circuit motor1 or su* z h be5 already describ$1 & :i* w />t "u ! action ( an alt]nat+ curr5t1 into a syn*roniz+ motor1 or "o :i* w be run by ! g5]ator only :5 x has rea*$ a c]ta9 spe$ ( rotation syn*ron\s ) t ( ! g5]ator4 ,9 ?is mann] he is enabl$ to ext5d v greatly ! applications ( 8 sy/em & to secure all ! advantages ( bo? =ms ( alt]nat+ curr5t motor4 ,! expression syn*ron\s ) t ( ! g5]ator1 is us$ "h 9 its ord9>y acceptation--t is to say1 a motor is said to syn*ronize ) ! g5]ator :5 x pres]ves a c]ta9 relative spe$ det]m9$ by its numb] ( poles & ! numb] ( alt]nations produc$ p] revolution ( ! g5]ator4 ,its actual spe$1 !re=e1 may be fa/] or sl[] ?an t ( ! g5]ator2 b x is said to be syn*ron\s s long z x pres]ves ! same relative spe$4 ,9 c>ry+ out ?is inv5tion ,mr4 ,tesla con/ructs a motor :i* has a /rong t5d5cy to syn*ronism ) ! g5]ator4 ,! con/ruction pref]r$ is t 9 :i* ! armature is provid$ ) pol> projections4 ,! field-magnets are w\nd ) two sets ( coils1 ! t]m9als ( :i* are connect$ to a swit* me*anism1 by means ( :i* ! l9e-curr5t may be c>ri$ directly ?r\gh ^! coils or indirectly ?r\gh pa?s by :i* its phases are modifi$4 ,to />t su* a motor1 ! swit* is turn$ on to a set ( contacts :i* includes 9 "o motor circuit a dead resi/ance1 9 ! o!r an inductive resi/ance1 &1 ! two circuits be+ 9 d]ivation1 x is obvi\s t ! diff]5ce 9 phase ( ! curr5t 9 su* circuits w set up a rotation ( ! motor4 ,:5 ! spe$ ( ! motor has ?us be5 br\ght to ! desir$ rate ! swit* is %ift$ to ?r[ ! ma9 curr5t directly ?r\gh ! motor-circuits1 & al?\gh ! curr5ts 9 bo? circuits w n[ be ( ! same phase ! motor w cont9ue to revolve1 becom+ a true syn*ron\s motor4 ,to secure great] effici5cy1 ! armature or its pol> projections are w\nd ) coils clos$ on !mselves4 ,9 ! accompany+ diagrams1 ,fig4 #ch illu/rates ! details ( ! plan above set =?1 & ,figs4 #ci & #dj modifications ( ! same4 ,illu/ration3 ,,figs4 #ch1 #ci & #dj4 ,ref]r+ to ,fig4 #ch1 let ,a designate ! field-magnets ( a motor1 ! pol> projections ( :i* are w\nd ) coils ,b ,c includ$ 9 indep5d5t circuits1 & ,d ! armature ) pol> projections w\nd ) coils ,e clos$ ^u !mselves1 ! motor 9 ^! respects be+ simil> 9 con/ruction to ^? describ$ already1 b hav+ on acc\nt ( ! pol> projections on ! armature core1 or o!r simil> & well-kn[n features1 ! prop]ties ( a syn*roniz+-motor4 ,l ,l' repres5ts ! conductors ( a l9e f an alt]nat+ curr5t g5]ator ,g4 ,ne> ! motor is plac$ a swit* ! action ( :i* is t ( ! "o %[n 9 ! diagrams1 :i* is con/ruct$ z foll[s3 ,f ,f' are two conduct+ plates or arms1 pivot$ at _! ends & connect$ by an insulat+ cross-b>1 ,h1 s z to be %ift$ 9 p>allelism4 ,9 ! pa? ( ! b>s ,f ,f' is ! contact #b1 :i* =ms "o t]m9al ( ! circuit ?r\gh coils ,c1 & ! contact #d1 :i* is "o t]m9al ( ! circuit ?r\gh coils ,b4 ,! opposite end ( ! wire ( coils ,c is connect$ to ! wire ,l or b> ,f'1 & ! correspond+ end ( coils ,b is connect$ to wire ,l' & b> ,f2 h5ce if ! b>s be %ift$ s z to be> on contacts #b & #d bo? sets ( coils ,b ,c w be includ$ 9 ! circuit ,l ,l' 9 multiple arc or d]ivation4 ,9 ! pa? ( ! lev]s ,f ,f' are two o!r contact t]m9als1 #a & #c4 ,! contact #a is connect$ to contact #b ?r\gh an artificial resi/ance1 ,i1 & contact #c ) contact #d ?r\gh a self-induction coil1 ,j1 s t :5 ! swit* lev]s are %ift$ ^u ! po9ts #a & #c ! circuits ( coils ,b & ,c w be connect$ 9 multiple arc or d]ivation to ! circuit ,l ,l'1 & w include ! resi/ance & self-induction coil respectively4 ,a ?ird position ( ! swit* is t 9 :i* ! lev]s ,f & ,f' are %ift$ out ( contact ) bo? sets ( po9ts4 ,9 ?is case ! motor is entirely out ( circuit4 ,! purpose & mann] ( op]at+ ! motor by ^! devices are z foll[s3 ,! normal position ( ! swit*1 ! motor be+ out ( circuit1 is (f ! contact po9ts4 ,assum+ ! g5]ator to be runn+1 & t x is desir$ to />t ! motor1 ! swit* is %ift$ until its lev]s re/ ^u po9ts #a & #c4 ,! two motor-circuits are ?us connect$ ) ! g5]ator circuit2 b by reason ( ! pres5ce ( ! resi/ance ,i 9 "o & ! self-induction coil ,j 9 ! o!r ! co9cid5ce ( ! phases ( ! curr5t is di/urb$ suffici5tly to produce a progression ( ! poles1 :i* />ts ! motor 9 rotation4 ,:5 ! spe$ ( ! motor has run up to syn*ronism ) ! g5]ator1 or approximately s1 ! swit* is %ift$ ov] ^u ! po9ts #b & #d1 ?us cutt+ out ! coils ,i & ,j1 s t ! curr5ts 9 bo? circuits h ! same phase2 b ! motor n[ runs z a syn*ron\s motor4 ,x w be und]/ood t :5 br\ght up to spe$ ! motor w run ) only "o ( ! circuits ,b or ,c connect$ ) ! ma9 or g5]ator circuit1 or ! two circuits may be connect$ 9 s]ies4 ,?is latt] plan is pref]able :5 a curr5t hav+ a high numb] ( alt]nations p] unit ( "t is employ$ to drive ! motor4 ,9 su* case ! />t+ ( ! motor is m difficult1 & ! dead & inductive resi/ances mu/ take up a consid]able proportion ( ! electromotive =ce ( ! circuits4 ,g5]ally ! conditions are s adju/$ t ! electromotive =ce us$ 9 ea* ( ! motor circuits is t :i* is requir$ to op]ate ! motor :5 its circuits are 9 s]ies4 ,! plan foll[$ 9 ?is case is illu/rat$ 9 ,fig4 #ci4 ,9 ?is in/ance ! motor has twelve poles & ! armature has pol> projections ,d w\nd ) clos$ coils ,e4 ,! swit* us$ is ( sub/antially ! same con/ruction z t %[n 9 ! previ\s figure4 ,!re are1 h[ev]1 five contacts1 designat$ z #e1 #f1 #g1 #h1 & #i4 ,! motor-circuits ,b ,c1 :i* include alt]nate field-coils1 are connect$ to ! t]m9als 9 ! foll[+ ord]3 ,"o end ( circuit ,c is connect$ to contact #i & to contact #e ?r\gh a dead resi/ance1 ,i4 ,"o t]m9al ( circuit ,b is connect$ to contact #g & to contact #f ?r\gh a self-induction coil1 ,j4 ,! opposite t]m9als ( bo? circuits are connect$ to contact #h4 ,"o ( ! lev]s1 z ,f1 ( ! swit* is made ) an ext5sion1 f1 or o!rwise1 s z to cov] bo? contacts #e & #f :5 %ift$ into ! position to />t ! motor4 ,x w be obs]v$ t :5 9 ?is position & ) lev] ,f' on contact #h ! curr5t divides betwe5 ! two circuits ,b ,c1 :i* f _! diff]5ce 9 electrical "* produce a progression ( ! poles t />ts ! motor 9 rotation4 ,:5 ! motor has atta9$ ! prop] spe$1 ! swit* is %ift$ s t ! lev]s cov] ! contacts #g & #i1 !reby connect+ circuits ,b & ,c 9 s]ies4 ,x is f\nd t by ?is disposition ! motor is ma9ta9$ 9 rotation 9 syn*ronism ) ! g5]ator4 ,?is pr9ciple ( op]ation1 :i* consi/s 9 conv]t+ by a *ange ( connections or o!rwise a d\ble-circuit motor1 or "o op]at+ by a progressive %ift+ ( ! poles1 into an ord9>y syn*roniz+ motor may be c>ri$ out 9 _m o!r ways4 ,= in/ance1 in/ead ( us+ ! swit* %[n 9 ! previ\s figures1 we may use a tempor>y gr\nd circuit betwe5 ! g5]ator & motor1 9 ord] to />t ! motor1 9 sub/antially ! mann] indicat$ 9 ,fig4 #dj4 ,let ,g 9 ?is figure repres5t an ord9>y alt]nat+-curr5t g5]ator )1 say1 two poles1 ,m ,m'1 & an armature w\nd ) two coils1 ,n ,n'1 at "r angles & connect$ 9 s]ies4 ,! motor has1 = example1 f\r poles w\nd ) coils ,b ,c1 :i* are connect$ 9 s]ies1 & an armature ) pol> projections ,d w\nd ) clos$ coils ,e ,e4 ,f ! common jo9t or union betwe5 ! two circuits ( bo? ! g5]ator & ! motor an e>? connection is e/abli%$1 :ile ! t]m9als or ends ( ^! circuits are connect$ to ! l9e4 ,assum+ t ! motor is a syn*roniz+ motor or "o t has ! capability ( runn+ 9 syn*ronism ) ! g5]ator1 b n ( />t+1 x may be />t$ by ! above-describ$ app>atus by clos+ ! gr\nd connection f bo? g5]ator & motor4 ,! sy/em ?us becomes "o ) a two-circuit g5]ator & motor1 ! gr\nd =m+ a common return = ! curr5ts 9 ! two circuits ,l & ,l'4 ,:5 by ?is arrangem5t ( circuits ! motor is br\ght to spe$1 ! gr\nd connection is brok5 betwe5 ! motor or g5]ator1 or bo?1 gr\nd-swit*es ,p ,p' be+ employ$ = ?is purpose4 ,! motor !n runs z a syn*roniz+ motor4 ,9 describ+ ! ma9 features :i* con/itute ?is inv5tion illu/rations h necess>ily be5 omitt$ ( ! appliances us$ 9 conjunction ) ! electrical devices ( simil> sy/ems--su*1 = in/ance1 z driv+-belts1 fix$ & loose pulleys = ! motor1 & ! l2 b ^! are matt]s well und]/ood4 ,mr4 ,tesla believes he is ! fir/ to op]ate electro-magnetic motors by alt]nat+ curr5ts 9 any ( ! ways h]e9 describ$--t is to say1 by produc+ a progressive movem5t or rotation ( _! poles or po9ts ( greate/ magnetic attraction by ! alt]nat+ curr5ts until !y h rea*$ a giv5 spe$1 & !n by ! same curr5ts produc+ a simple alt]nation ( _! poles1 or1 9 o!r words1 by a *ange 9 ! ord] or "* ( ! circuit connections to conv]t a motor op]at+ on "o pr9ciple to "o op]at+ on ano!r4 ,,*apt] ,,ix4 ,,*ange ,,f ,,d\ble ,,curr5t ,,to ,,s+le ,,curr5t ,,motor4 ,a description is giv5 else:]e ( a me?od ( op]at+ alt]nat+ curr5t motors by fir/ rotat+ _! magnetic poles until !y h atta9$ syn*ron\s spe$1 & !n alt]nat+ ! poles4 ,! motor is ?us trans=m$1 by a simple *ange ( circuit connections f "o op]at$ by ! action ( two or m indep5d5t en]giz+ curr5ts to "o op]at$ ei!r by a s+le curr5t or by sev]al curr5ts act+ z "o4 ,ano!r way ( do+ ?is w n[ be describ$4 ,at ! />t ! magnetic poles ( "o elem5t or field ( ! motor are progressively %ift$ by alt]nat+ curr5ts diff]+ 9 phase & pass$ ?r\gh indep5d5t en]giz+ circuits1 & %ort circuit ! coils ( ! o!r elem5t4 ,:5 ! motor ?us />t$ rea*es or passes ! limit ( spe$ syn*ron\s ) ! g5]ator1 ,mr4 ,tesla connects up ! coils previ\sly %ort-circuit$ ) a s\rce ( direct curr5t & by a *ange ( ! circuit connections produces a simple alt]nation ( ! poles4 ,! motor !n cont9ues to run 9 syn*ronism ) ! g5]ator4 ,! motor "h %[n 9 ,fig4 #da is "o ( ! ord9>y =ms1 ) field-cores ei!r lam9at$ or solid & ) a cyl9drical lam9at$ armature w\nd1 = example1 ) ! coils ,a ,b at "r angles4 ,! %aft ( ! armature c>ries ?ree collect+ or contact r+s ,c ,d ,e4 7,%[n1 = bett] illu/ration1 z ( diff]5t diamet]s47 ,"o end ( coil ,a connects to "o r+1 z ,c1 & "o end ( coil ,b connects ) r+ ,d4 ,! rema9+ ends are connect$ to r+ ,e4 ,collect+ spr+s or bru%es ,f ,g ,h be> ^u ! r+s & lead to ! contacts ( a swit*1 to be pres5tly describ$4 ,! field-coils h _! t]m9als 9 b9d+-po/s ,k ,k1 & may be ei!r clos$ ^u !mselves or connect$ ) a s\rce ( direct curr5t ,l1 by means ( a swit* ,m4 ,! ma9 or controll+ swit* has five contacts a b c d e & two lev]s f g1 pivot$ & connect$ by an insulat+ cross-b> h1 s z to move 9 p>allelism4 ,^! lev]s are connect$ to ! l9e wires f a s\rce ( alt]nat+ curr5ts ,n4 ,contact a is connect$ to bru% ,g & coil ,b ?r\gh a dead resi/ance ,r & wire ,p4 ,contact b is connect$ ) bru% ,f & coil ,a ?r\gh a self-induction coil ,s & wire ,o4 ,contacts c & e are connect$ to bru%es ,g ,f1 respectively1 ?r\gh ! wires ,p ,o1 & contact d is directly connect$ ) bru% ,h4 ,! lev] f has a wid5$ end1 :i* may span ! contacts a b4 ,:5 9 su* position & ) lev] g on contact d1 ! alt]nat+ curr5ts divide betwe5 ! two motor-coils1 & by reason ( _! diff]5t self-induction a diff]5ce ( curr5t-phase is obta9$ t />ts ! motor 9 rotation4 ,9 />t+1 ! field-coils are %ort circuit$4 ,illu/ration3 ,,fig4 #da4 ,:5 ! motor has atta9$ ! desir$ spe$1 ! swit* is %ift$ to ! position %[n 9 dott$ l9es--t is to say1 ) ! lev]s f g re/+ on po9ts c e4 ,?is connects up ! two armature coils 9 s]ies1 & ! motor w !n run z a syn*ron\s motor4 ,! field-coils are ?r[n into circuit ) ! direct curr5t s\rce :5 ! ma9 swit* is %ift$4 ,,*apt] ,x4 ,,motor ,,) ,,curr5t ,,lag ,,artificially ,,secur$4 ,"o ( ! g5]al ways foll[$ by ,mr4 ,tesla 9 develop+ 8 rot>y phase motors is to produce practically indep5d5t curr5ts diff]+ prim>ily 9 phase & to pass ^! ?r\gh ! motor-circuits4 ,ano!r way is to produce a s+le alt]nat+ curr5t1 to divide x betwe5 ! motor-circuits1 & to effect artificially a lag 9 "o ( ^! circuits or bran*es1 z by giv+ to ! circuits diff]5t self-inductive capacity1 & 9 o!r ways4 ,9 ! =m] case1 9 :i* ! necess>y diff]5ce ( phase is prim>ily effect$ 9 ! g5]ation ( curr5ts1 9 "s in/ances1 ! curr5ts are pass$ ?r\gh ! en]giz+ coils ( bo? elem5ts ( ! motor--! field & armature2 b a fur!r result or modification may be obta9$ by do+ ?is "u ! conditions h]e9aft] specifi$ 9 ! case ( motors 9 :i* ! lag1 z above /at$1 is artificially secur$4 ,figs4 #db to #dg1 inclusive1 are diagrams ( diff]5t ways 9 :i* ! inv5tion is c>ri$ out2 & ,fig4 #dh1 a side view ( a =m ( motor us$ by ,mr4 ,tesla = ?is purpose4 ,illu/ration3 ,,figs4 #db1 #dc & #dd4 ,a ,b 9 ,fig4 #db indicate ! two en]giz+ circuits ( a motor1 & ,c ,d two circuits on ! armature4 ,circuit or coil ,a is connect$ 9 s]ies ) circuit or coil ,c1 & ! two circuits ,b ,d are simil>ly connect$4 ,betwe5 coils ,a & ,c is a contact-r+ e1 =m+ "o t]m9al ( ! latt]1 & a bru% a1 =m+ "o t]m9al ( ! =m]4 ,a r+ d & bru% c simil>ly connect coils ,b & ,d4 ,! opposite t]m9als ( ! field-coils connect to "o b9d+ po/ h ( ! motor1 & ^? ( ! armature coils are simil>ly connect$ to ! opposite b9d+ po/ i ?r\gh a contact-r+ f & bru% g4 ,?us ea* motor-circuit :ile 9 d]ivation to ! o!r includes "o armature & "o field coil4 ,^! circuits are ( diff]5t self-induction1 & may be made s 9 v>i\s ways4 ,= ! sake ( cle>ness1 an artificial resi/ance ,r is %[n 9 "o ( ^! circuits1 & 9 ! o!r a self-induction coil ,s4 ,:5 an alt]nat+ curr5t is pass$ ?r\gh ?is motor x divides betwe5 its two en]giz+-circuits4 ,! high] self-induction ( "o circuit produces a great] ret>dation or lag 9 ! curr5t !re9 ?an 9 ! o!r4 ,! diff]5ce ( phase betwe5 ! two curr5ts effects ! rotation or %ift+ ( ! po9ts ( maximum magnetic effect t secures ! rotation ( ! armature4 ,9 c]ta9 respects ?is plan ( includ+ bo? armature & field coils 9 circuit is a m>k$ improvem5t4 ,su* a motor has a good torque at />t+2 yet x has also consid]able t5d5cy to syn*ronism1 ow+ to ! fact t :5 prop]ly con/ruct$ ! maximum magnetic effects 9 bo? armature & field co9cide--a condition :i* 9 ! usual con/ruction ( ^! motors ) clos$ armature coils is n readily atta9$4 ,! motor ?us con/ruct$ exhibits too1 a bett] regulation ( curr5t f no load to load1 & !re is less diff]5ce betwe5 ! app>5t & real en]gy exp5d$ 9 runn+ x4 ,! true syn*ron\s spe$ ( ?is =m ( motor is t ( ! g5]ator :5 bo? are alike--t is to say1 if ! numb] ( ! coils on ! armature & on ! field is x1 ! motor w run normally at ! same spe$ z a g5]ator driv+ x if ! numb] ( field magnets or poles ( ! same be also x4 ,illu/ration3 ,,figs4 #de1 #df & #dg4 ,fig4 #dc %[s a some:at modifi$ arrangem5t ( circuits4 ,!re is 9 ?is case b "o armature coil ,e1 ! w9d+ ( :i* ma9ta9s effects correspond+ to ! resultant poles produc$ by ! two field-circuits4 ,fig4 #dd repres5ts a disposition 9 :i* bo? armature & field are w\nd ) two sets ( coils1 all 9 multiple arc to ! l9e or ma9 circuit4 ,! armature coils are w\nd to correspond ) ! field-coils ) respect to _! self-induction4 ,a modification ( ?is plan is %[n 9 ,fig4 #de--t is to say1 ! two field coils & two armature coils are 9 d]ivation to !mselves & 9 s]ies ) "o ano!r4 ,! armature coils 9 ?is case1 z 9 ! previ\s figure1 are w\nd = diff]5t self-induction to correspond ) ! field coils4 ,ano!r modification is %[n 9 ,fig4 #df4 ,9 ?is case only "o armature-coil1 z ,d1 is includ$ 9 ! l9e-circuit1 :ile ! o!r1 z ,c1 is %ort-circuit$4 ,9 su* a disposition z t %[n 9 ,fig4 #dc1 or :]e only "o armature-coil is employ$1 ! torque on ! />t is some:at r$uc$1 :ile ! t5d5cy to syn*ronism is some:at increas$4 ,9 su* a disposition z %[n 9 ,fig4 #df1 ! opposite conditions w\ld exi/4 ,9 bo? in/ances1 h[ev]1 !re is ! advantage ( disp5s+ ) "o contact-r+4 ,illu/ration3 ,,fig4 #dh4 ,9 ,fig4 #df ! two field-coils & ! armature-coil ,d are 9 multiple arc4 ,9 ,fig4 #dg ?is disposition is modifi$1 coil ,d be+ %[n 9 s]ies ) ! two field-coils4 ,fig4 #dh is an outl9e ( ! g5]al =m ( motor 9 :i* ?is inv5tion is embodi$4 ,! circuit connections betwe5 ! armature & field coils are made1 z indicat$ 9 ! previ\s figures1 ?r\gh bru%es & r+s1 :i* are n %[n4 ,,*apt] ,,xi4 ,,ano!r ,,me?od ,,( ,,trans=mation ,,f ,a ,,torque ,,to ,a ,,syn*roniz+ ,,motor4 ,9 a prec$+ *apt] we h describ$ a me?od by :i* ,mr4 ,tesla accompli%es ! *ange 9 8 type ( rotat+ field motor f a torque to a syn*roniz+ motor4 ,z w be obs]v$1 ! desir$ end is !re rea*$ by a *ange 9 ! circuit connections at ! prop] mom5t4 ,we w n[ proce$ to describe ano!r way ( br++ ab\t ! same result4 ,! pr9ciple involv$ 9 ?is me?od is z foll[s3-- ,if an alt]nat+ curr5t be pass$ ?r\gh ! field coils only ( a motor hav+ two en]giz+ circuits ( diff]5t self-induction & ! armature coils be %ort-circuit$1 ! motor w h a /rong torque1 b little or no t5d5cy to syn*ronism ) ! g5]ator2 b if ! same curr5t :i* en]gizes ! field be pass$ also ?r\gh ! armature coils ! t5d5cy to rema9 9 syn*ronism is v consid]ably increas$4 ,?is is due to ! fact t ! maximum magnetic effects produc$ 9 ! field & armature m ne>ly co9cide4 ,on ?is pr9ciple ,mr4 ,tesla con/ructs a motor hav+ indep5d5t field circuits ( diff]5t self-induction1 :i* are jo9$ 9 d]ivation to a s\rce ( alt]nat+ curr5ts4 ,! armature is w\nd ) "o or m coils1 :i* are connect$ ) ! field coils ?r\gh contact r+s & bru%es1 & ar\nd ! armature coils a %unt is arrang$ ) means = op5+ or clos+ ! same4 ,9 />t+ ?is motor ! %unt is clos$ ar\nd ! armature coils1 :i* w !re=e be 9 clos$ circuit4 ,:5 ! curr5t is direct$ ?r\gh ! motor1 x divides betwe5 ! two circuits1 7x is n necess>y to consid] any case :]e !re are m ?an two circuits us$71 :i*1 by reason ( _! diff]5t self-induction1 secure a diff]5ce ( phase betwe5 ! two curr5ts 9 ! two bran*es1 t produces a %ift+ or rotation ( ! poles4 ,by ! alt]nations ( curr5t1 o!r curr5ts are induc$ 9 ! clos$--or %ort-circuit$--armature coils & ! motor has a /rong torque4 ,:5 ! desir$ spe$ is rea*$1 ! %unt ar\nd ! armature-coils is op5$ & ! curr5t direct$ ?r\gh bo? armature & field coils4 ,"u ^! conditions ! motor has a /rong t5d5cy to syn*ronism4 ,illu/ration3 ,,figs4 #di1 #ej & #ea4 ,9 ,fig4 #di1 ,a & ,b designate ! field coils ( ! motor4 ,z ! circuits includ+ ^! coils are ( diff]5t self-induction1 ?is is repres5t$ by a resi/ance coil ,r 9 circuit ) ,a1 & a self-induction coil ,s 9 circuit ) ,b4 ,! same result may ( c\rse be secur$ by ! w9d+ ( ! coils4 ,c is ! armature circuit1 ! t]m9als ( :i* are r+s a b4 ,bru%es c d be> on ^! r+s & connect ) ! l9e & field circuits4 ,d is ! %unt or %ort circuit ar\nd ! armature4 ,e is ! swit* 9 ! %unt4 ,x w be obs]v$ t 9 su* a disposition z is illu/rat$ 9 ,fig4 #di1 ! field circuits ,a & ,b be+ ( diff]5t self-induction1 !re w always be a great] lag ( ! curr5t 9 "o ?an ! o!r1 & t1 g5]ally1 ! armature phases w n correspond ) ei!r1 b ) ! resultant ( bo?4 ,x is !re=e important to obs]ve ! prop] rule 9 w9d+ ! armature4 ,= in/ance1 if ! motor h eight poles--f\r 9 ea* circuit--!re w be f\r resultant poles1 & h5ce ! armature w9d+ %\ld be su* z to produce f\r poles1 9 ord] to con/itute a true syn*roniz+ motor4 ,illu/ration3 ,,fig4 #eb4 ,! diagram1 ,fig4 #ej1 diff]s f ! previ\s "o only 9 respect to ! ord] ( connections4 ,9 ! pres5t case ! armature-coil1 in/ead ( be+ 9 s]ies ) ! field-coils1 is 9 multiple arc !re)4 ,! armature-w9d+ may be simil> to t ( ! field--t is to say1 ! armature may h two or m coils w\nd or adapt$ = diff]5t self-induction & adapt$1 pref]ably1 to produce ! same diff]5ce ( phase z ! field-coils4 ,on />t+ ! motor ! %unt is clos$ ar\nd bo? coils4 ,?is is %[n 9 ,fig4 #ea1 9 :i* ! armature coils are ,f ,g4 ,to indicate _! diff]5t electrical "*1 !re are %[n 9 circuit ) !m1 respectively1 ! resi/ance ,r' & ! self-induction coil ,s'4 ,! two armature coils are 9 s]ies ) ! field-coils & ! same disposition ( ! %unt or %ort-circuit ,d is us$4 ,x is ( advantage 9 ! op]ation ( motors ( ?is k9d to con/ruct or w9d ! armature 9 su* mann] t :5 %ort-circuit$ on ! />t x w h a t5d5cy to rea* a high] spe$ ?an t :i* syn*ronizes ) ! g5]ator4 ,= example1 a giv5 motor hav+1 say1 eight poles %\ld run1 ) ! armature coil %ort-circuit$1 at two ?\s& revolutions p] m9ute to br+ x up to syn*ronism4 ,x w g5]ally happ51 h[ev]1 t ?is spe$ is n rea*$1 ow+ to ! fact t ! armature & field curr5ts d n prop]ly correspond1 s t :5 ! curr5t is pass$ ?r\gh ! armature 7! motor n be+ q up to syn*ronism7 !re is a liability t x w n hold on1 z x is t]m$4 ,x is pref]able1 !re=e1 to s w9d or con/ruct ! motor t on ! />t1 :5 ! armature coils are %ort-circuit$1 ! motor w t5d to rea* a spe$ high] ?an ! syn*ron\s--z = in/ance1 d\ble ! latt]4 ,9 su* case ! difficulty above allud$ to is n felt1 = ! motor w always hold up to syn*ronism if ! syn*ron\s spe$--9 ! case suppos$ ( two ?\s& revolutions--is rea*$ or pass$4 ,?is may be accompli%$ 9 v>i\s ways2 b = all practical purposes ! foll[+ w suffice3 ,on ! armature are w\nd two sets ( coils4 ,at ! />t only "o ( ^! is %ort-circuit$1 !reby produc+ a numb] ( poles on ! armature1 :i* w t5d to run ! spe$ up above ! syn*ron\s limit4 ,:5 su* limit is rea*$ or pass$1 ! curr5t is direct$ ?r\gh ! o!r coil1 :i*1 by increas+ ! numb] ( armature poles1 t5ds to ma9ta9 syn*ronism4 ,illu/ration3 ,,fig4 #ec4 ,9 ,fig4 #eb1 su* a disposition is %[n4 ,! motor hav+1 say1 eight poles conta9s two field-circuits ,a & ,b1 ( diff]5t self-induction4 ,! armature has two coils ,f & ,g4 ,! =m] is clos$ ^u itself1 ! latt] connect$ ) ! field & l9e ?r\gh contact-r+s a b1 bru%es c d1 & a swit* ,e4 ,on ! />t ! coil ,f alone is active & ! motor t5ds to run at a spe$ above ! syn*ron\s2 b :5 ! coil ,g is connect$ to ! circuit ! numb] ( armature poles is increas$1 :ile ! motor is made a true syn*ron\s motor4 ,?is disposition has ! advantage t ! clos$ armature-circuit imp>ts to ! motor torque :5 ! spe$ falls (f1 b at ! same "t ! conditions are su* t ! motor comes out ( syn*ronism m readily4 ,to increase ! t5d5cy to syn*ronism1 two circuits may be us$ on ! armature1 "o ( :i* is %ort-circuit$ on ! />t & bo? connect$ ) ! ext]nal circuit aft] ! syn*ron\s spe$ is rea*$ or pass$4 ,?is disposition is %[n 9 ,fig4 #ec4 ,!re are ?ree contact-r+s a b e & ?ree bru%es c d f1 :i* connect ! armature circuits ) ! ext]nal circuit4 ,on />t+1 ! swit* ,h is turn$ to complete ! connection betwe5 "o b9d+-po/ ,p & ! field-coils4 ,?is %ort-circuits "o ( ! armature-coils1 z ,g4 ,! o!r coil ,f is out ( circuit & op54 ,:5 ! motor is up to spe$1 ! swit* ,h is turn$ back1 s t ! connection f b9d+-po/ ,p to ! field coils is ?r\gh ! coil ,g1 & swit* ,k is clos$1 !reby includ+ coil ,f 9 multiple arc ) ! field coils4 ,bo? armature coils are ?us active4 ,f ! above-describ$ in/ances x is evid5t t _m o!r dispositions = c>ry+ out ! inv5tion are possible4 ,,*apt] ,,xii4 ,,magnetic ,,lag ,,motor4 ,! foll[+ description deals ) ano!r =m ( motor1 namely1 dep5d+ on magnetic lag or hy/]esis1 its peculi>ity be+ t 9 x ! attractive effects or phases :ile lagg+ beh9d ! phases ( curr5t :i* produce !m1 are manife/$ simultane\sly & n successively4 ,! ph5om5on utiliz$ ?us at an e>ly /age by ,mr4 ,tesla1 0 n g5]ally believ$ 9 by sci5tific m51 & ,pr(4 ,ayrton 0 probably fir/ to advocate x or to elucidate ! reason ( its suppos$ exi/5ce4 ,fig4 #ed is a side view ( ! motor1 9 elevation4 ,fig4 #ee is a "p-sectional view at "r angles to ,fig4 #ed4 ,fig4 #ef is an end view 9 elevation & "p section ( a modification1 & ,fig4 #eg is a simil> view ( ano!r modification4 ,9 ,figs4 #ed & #ee1 ,a designates a base or /&1 & ,b ,b ! support+-frame ( ! motor4 ,bolt$ to ! support+-frame are two magnetic cores or pole-pieces ,c ,c'1 ( iron or s(t /eel4 ,^! may be subdivid$ or lam9at$1 9 :i* case h>d iron or /eel plates or b>s %\ld be us$1 or !y %\ld be w\nd ) clos$ coils4 ,d is a circul> disc armature1 built up ( sections or plates ( iron & m\nt$ 9 ! frame betwe5 ! pole-pieces ,c ,c'1 curv$ to con=m to ! circul> %ape !re(4 ,?is disc may be w\nd ) a numb] ( clos$ coils ,e4 ,f ,f are ! ma9 en]giz+ coils1 support$ by ! support+-frame1 s z to include )9 _! magnetiz+ influ5ce bo? ! pole-pieces ,c ,c' & ! armature ,d4 ,! pole-pieces ,c ,c' project out beyond ! coils ,f ,f on opposite sides1 z indicat$ 9 ! draw+s4 ,if an alt]nat+ curr5t be pass$ ?r\gh ! coils ,f ,f1 rotation ( ! armature w be produc$1 & ?is rotation is expla9$ by ! foll[+ app>5t action1 or mode ( op]ation3 ,an impulse ( curr5t 9 ! coils ,f ,f e/abli%es two pol>ities 9 ! motor4 ,! protrud+ end ( pole-piece ,c1 = in/ance1 w be ( "o sign1 & ! correspond+ end ( pole-piece ,c' w be ( ! opposite sign4 ,! armature also exhibits two poles at "r angles to ! coils ,f ,f1 l poles to ^? 9 ! pole-pieces be+ on ! same side ( ! coils4 ,:ile ! curr5t is fl[+ !re is no appreciable t5d5cy to rotation develop$2 b aft] ea* curr5t impulse ceases or beg9s to fall1 ! magnetism 9 ! armature & 9 ! ends ( ! pole-pieces ,c ,c' lags or cont9ues to manife/ itself1 :i* produces a rotation ( ! armature by ! repell5t =ce betwe5 ! m closely approximat+ po9ts ( maximum magnetic effect4 ,?is effect is cont9u$ by ! rev]sal ( curr5t1 ! pol>ities ( field & armature be+ simply rev]s$4 ,"o or bo? ( ! elem5ts--! armature or field--may be w\nd ) clos$ induc$ coils to int5sify ?is effect4 ,al?\gh 9 ! illu/rations b "o ( ! fields is %[n1 ea* elem5t ( ! motor really con/itutes a field1 w\nd ) ! clos$ coils1 ! curr5ts be+ induc$ ma9ly 9 ^? convolutions or coils :i* are p>allel to ! coils ,f ,f4 ,illu/ration3 ,,fig4 #ed4 ,illu/ration3 ,,fig4 #ee4 ,a modifi$ =m ( ?is motor is %[n 9 ,fig4 #ef4 ,9 ?is =m ,g is "o ( two /&>ds t support ! be>+s = ! armature-%aft4 ,h ,h are uprights or sides ( a frame1 pref]ably magnetic1 ! ends ,c ,c' ( :i* are b5t 9 ! mann] indicat$1 to con=m to ! %ape ( ! armature ,d & =m field-magnet poles4 ,! con/ruction ( ! armature may be ! same z 9 ! previ\s figure1 or x may be simply a magnetic disc or cyl9d]1 z %[n1 & a coil or coils ,f ,f are secur$ 9 position to surr\nd bo? ! armature & ! poles ,c ,c'4 ,! armature is deta*able f its %aft1 ! latt] be+ pass$ ?r\gh ! armature aft] x has be5 ins]t$ 9 position4 ,! op]ation ( ?is =m ( motor is ! same 9 pr9ciple z t previ\sly describ$ & ne$s no fur!r explanation4 ,illu/ration3 ,,fig4 #ef4 ,illu/ration3 ,,fig4 #eg4 ,"o ( ! mo/ important features 9 alt]nat+ curr5t motors is1 h[ev]1 t !y %\ld be adapt$ to & capable ( runn+ effici5tly on ! alt]nat+ circuits 9 pres5t use1 9 :i* almo/ )\t exception ! g5]ators yield a v high numb] ( alt]nations4 ,su* a motor1 ( ! type "u consid]ation1 ,mr4 ,tesla has design$ by a developm5t ( ! pr9ciple ( ! motor %[n 9 ,fig4 #ef1 mak+ a multipol> motor1 :i* is illu/rat$ 9 ,fig4 #eg4 ,9 ! con/ruction ( ?is motor he employs an annul> magnetic frame ,j1 ) inw>dly-ext5d+ ribs or projections ,k1 ! ends ( :i* all b5d or turn 9 "o direction & are g5]ally %ap$ to con=m to ! curv$ surface ( ! armature4 ,coils ,f ,f are w\nd f "o "p ,k to ! "o next adjac5t1 ! ends or loops ( ea* coil or gr\p ( wires be+ c>ri$ ov] t[>d ! %aft1 s z to =m ,u-%ap$ gr\ps ( convolutions at ea* end ( ! armature4 ,! pole-pieces ,c ,c'1 be+ sub/antially conc5tric ) ! armature1 =m l$ges1 along :i* ! coils are laid & %\ld project to "s ext5t beyond ! ! coils1 z %[n4 ,! cyl9drical or drum armature ,d is ( ! same con/ruction z 9 ! o!r motors describ$1 & is m\nt$ to rotate )9 ! annul> frame ,j & betwe5 ! ,u-%ap$ ends or b5ds ( ! coils ,f4 ,! coils ,f are connect$ 9 multiple or 9 s]ies ) a s\rce ( alt]nat+ curr5ts1 & are s w\nd t ) a curr5t or curr5t impulse ( giv5 direction !y w make ! alt]nate pole-pieces ,c ( "o pol>ity & ! o!r pole-pieces ,c' ( ! opposite pol>ity4 ,! pr9ciple ( ! op]ation ( ?is motor is ! same z ! o!r above describ$1 =1 consid]+ any two pole-pieces ,c ,c'1 a curr5t impulse pass+ 9 ! coil :i* bridges !m or is w\nd ov] bo? t5ds to e/abli% pol>ities 9 _! ends ( opposite sign & to set up 9 ! armature core betwe5 !m a pol>ity ( ! same sign z t ( ! ne>e/ pole-piece ,c4 ,^u ! fall or cessation ( ! curr5t impulse t e/abli%$ ^! pol>ities ! magnetism :i* lags beh9d ! curr5t phase1 & :i* cont9ues to manife/ itself 9 ! pol> projections ,c ,c' & ! armature1 produces by repulsion a rotation ( ! armature4 ,! effect is cont9u$ by ea* rev]sal ( ! curr5t4 ,:at occurs 9 ! case ( "o pair ( pole-pieces occurs simultane\sly 9 all1 s t ! t5d5cy to rotation ( ! armature is measur$ by ! sum ( all ! =ces ex]t$ by ! pole-pieces1 z above describ$4 ,9 ?is motor also ! magnetic lag or effect is int5sifi$ by w9d+ "o or bo? cores ) clos$ induc$ coils4 ,! armature core is %[n z ?us w\nd4 ,:5 clos$ coils are us$1 ! cores %\ld be lam9at$4 ,x is evid5t t a pulsatory z well z an alt]nat+ curr5t might be us$ to drive or op]ate ! motors above describ$4 ,x w be und]/ood t ! degree ( subdivision1 ! mass ( ! iron 9 ! cores1 _! size & ! numb] ( alt]nations 9 ! curr5t employ$ to run ! motor1 mu/ be tak5 into consid]ation 9 ord] to prop]ly con/ruct ?is motor4 ,9 o!r words1 9 all su* motors ! prop] relations betwe5 ! numb] ( alt]nations & ! mass1 size1 or quality ( ! iron mu/ be pres]v$ 9 ord] to secure ! be/ results4 ,,*apt] ,,xiii4 ,,me?od ,,( ,,obta9+ ,,diff]5ce ,,( ,,phase ,,by ,,magnetic ,,%ield+4 ,9 t class ( motors 9 :i* two or m sets ( en]giz+ magnets are employ$1 & 9 :i* by artificial means a c]ta9 int]val ( "t is made to elapse betwe5 ! respective maximum or m9imum p]iods or phases ( _! magnetic attraction or effect1 ! int]val or diff]5ce 9 phase betwe5 ! two sets ( magnets is limit$ 9 ext5t4 ,x is desirable1 h[ev]1 = ! economical work+ ( su* motors t ! /r5g? or attraction ( "o set ( magnets %\ld be maximum1 at ! "t :5 t ( ! o!r set is m9imum1 & conv]sely2 b ^! conditions h n h]et(ore be5 realiz$ except 9 cases :]e ! two curr5ts h be5 obta9$ f indep5d5t s\rces 9 ! same or diff]5t ma*9es4 ,mr4 ,tesla has !re=e devis$ a motor embody+ conditions t approa* m ne>ly ! !oretical requirem5ts ( p]fect work+1 or 9 o!r words1 he produces artificially a diff]5ce ( magnetic phase by means ( a curr5t f a s+le prim>y s\rce suffici5t 9 ext5t to meet ! requirem5ts ( practical & economical work+4 ,he employs a motor ) two sets ( en]giz+ or field magnets1 ea* w\nd ) coils connect$ ) a s\rce ( alt]nat+ or rapidly-v>y+ curr5ts1 b =m+ two sep>ate pa?s or circuits4 ,! magnets ( "o set are protect$ to a c]ta9 ext5t f ! en]giz+ action ( ! curr5t by means ( a magnetic %ield or scre5 int]pos$ betwe5 ! magnet & its en]giz+ coil4 ,?is %ield is prop]ly adapt$ to ! conditions ( p>ticul> cases1 s z to %ield or protect ! ma9 core f magnetization until x has become itself saturat$ & no long] capable ( conta9+ all ! l9es ( =ce produc$ by ! curr5t4 ,x w be se5 t by ?is means ! en]giz+ action beg9s 9 ! protect$ set ( magnets a c]ta9 arbitr>ily-det]m9$ p]iod ( "t lat] ?an 9 ! o!r1 & t by ?is means alone or 9 conjunction ) o!r means or devices h]et(ore employ$ a practical diff]5ce ( magnetic phase may readily be secur$4 ,fig4 #eh is a view ( a motor1 p>tly 9 section1 ) a diagram illu/rat+ ! inv5tion4 ,fig4 #ei is a simil> view ( a modification ( ! same4 ,illu/ration3 ,,fig4 #eh4 ,illu/ration3 ,,fig4 #ei4 ,9 ,fig4 #eh1 :i* exhibits ! simple/ =m ( ! inv5tion1 ,a ,a is ! field-magnet ( a motor1 hav+1 say1 eight poles or inw>dly-project+ cores ,b & ,c4 ,! cores ,b =m "o set ( magnets & are en]giz$ by coils ,d4 ,! cores ,c1 =m+ ! o!r set are en]giz$ by coils ,e1 & ! coils are connect$1 pref]ably1 9 s]ies ) "o ano!r1 9 two d]iv$ or bran*$ circuits1 ,f ,g1 respectively1 f a suitable s\rce ( curr5t4 ,ea* coil ,e is surr\nd$ by a magnetic %ield ,h1 :i* is pref]ably compos$ ( an anneal$1 insulat$1 or oxidiz$ iron wire wrapp$ or w\nd on ! coils 9 ! mann] indicat$ s z to =m a clos$ magnetic circuit ar\nd ! coils & betwe5 ! same & ! magnetic cores ,c4 ,betwe5 ! pole pieces or cores ,b ,c is m\nt$ ! armature ,k1 :i*1 z is usual 9 ?is type ( ma*9es1 is w\nd ) coils ,l clos$ ^u !mselves4 ,! op]ation result+ f ?is disposition is z foll[s3 ,if a curr5t impulse be direct$ ?r\gh ! two circuits ( ! motor1 x w quickly en]gize ! cores ,b1 b n s ! cores ,c1 = ! reason t 9 pass+ ?r\gh ! coils ,e !re is enc\nt]$ ! influ5ce ( ! clos$ magnetic circuits =m$ by ! %ields ,h4 ,! fir/ effect is to ret>d effectively ! curr5t impulse 9 circuit ,g1 :ile at ! same "t ! proportion ( curr5t :i* does pass does n magnetize ! cores ,c1 :i* are %ield$ or scre5$ by ! %ields ,h4 ,z ! increas+ electromotive =ce !n urges m curr5t ?r\gh ! coils ,e1 ! iron wire ,h becomes magnetically saturat$ & incapable ( c>ry+ all ! l9es ( =ce1 & h5ce ceases to protect ! cores ,c1 :i* becomes magnetiz$1 develop+ _! maximum effect aft] an int]val ( "t subsequ5t to ! simil> manife/ation ( /r5g? 9 ! o!r set ( magnets1 ! ext5t ( :i* is arbitr>ily det]m9$ by ! ?ickness ( ! %ield ,h1 & o!r well-und]/ood conditions4 ,f ! above x w be se5 t ! app>atus or device acts 9 two ways4 ,fir/1 by ret>d+ ! curr5t1 &1 second1 by ret>d+ ! magnetization ( "o set ( ! cores1 f :i* its effectiv5ess w readily appe>4 ,_m modifications ( ! pr9ciple ( ?is inv5tion are possible4 ,"o useful & effici5t application ( ! inv5tion is %[n 9 ,fig4 #ei4 ,9 ?is figure a motor is %[n simil> 9 all respects to t above describ$1 except t ! iron wire ,h1 :i* is wrapp$ ar\nd ! coils ,e1 is 9 ?is case connect$ 9 s]ies ) ! coils ,d4 ,! iron-wire coils ,h1 are connect$ & w\nd1 s z to h little or no self-induction1 & be+ add$ to ! resi/ance ( ! circuit ,f1 ! action ( ! curr5t 9 t circuit w be accel]at$1 :ile 9 ! o!r circuit ,g x w be ret>d$4 ,! %ield ,h may be made 9 _m =ms1 z w be und]/ood1 & us$ 9 diff]5t ways1 z appe>s f ! =ego+ description4 ,z a modification ( 8 type ( motor ) %ield$ fields1 ,mr4 ,tesla has con/ruct$ a motor ) a field-magnet hav+ two sets ( poles or inw>dly-project+ cores & plac$ side by side1 s z practically to =m two fields ( =ce & alt]nately dispos$--t is to say1 ) ! poles ( "o set or field opposite ! spaces betwe5 ! o!r4 ,he !n connects ! free ends ( "o set ( poles by means ( lam9at$ iron b&s or bridge-pieces ( consid]ably small] cross-section ?an ! cores !mselves1 :]eby ! cores w all =m p>ts ( complete magnetic circuits4 ,:5 ! coils on ea* set ( magnets are connect$ 9 multiple circuits or bran*es f a s\rce ( alt]nat+ curr5ts1 electromotive =ces are set up 9 or impress$ ^u ea* circuit simultane\sly2 b ! coils on ! magnetically bridg$ or %unt$ cores w h1 by reason ( ! clos$ magnetic circuits1 a high self-induction1 :i* ret>ds ! curr5t1 p]mitt+ at ! beg9n+ ( ea* impulse b little curr5t to pass4 ,on ! o!r h&1 no su* opposition be+ enc\nt]$ 9 ! o!r set ( coils1 ! curr5t passes freely ?r\gh !m1 magnetiz+ ! poles on :i* !y are w\nd4 ,z soon1 h[ev]1 z ! lam9at$ bridges become saturat$ & incapable ( c>ry+ all ! l9es ( =ce :i* ! ris+ electromotive =ce1 & consequ5tly increas$ curr5t1 produce1 free poles are develop$ at ! ends ( ! cores1 :i*1 act+ 9 conjunction ) ! o!rs1 produce rotation ( ! armature4 ,! con/ruction 9 detail by :i* ?is inv5tion is illu/rat$ is %[n 9 ! accompany+ draw+s4 ,illu/ration3 ,,fig4 #fj4 ,illu/ration3 ,,fig4 #fa4 ,fig4 #fj is a view 9 side elevation ( a motor embody+ ! pr9ciple4 ,fig4 #fa is a v]tical cross-section ( ! motor4 ,a is ! frame ( ! motor1 :i* %\ld be built up ( %eets ( iron pun*$ out to ! desir$ %ape & bolt$ toge!r ) insulation betwe5 ! %eets4 ,:5 complete1 ! frame makes a field-magnet ) inw>dly project+ pole-pieces ,b & ,c4 ,to adapt !m to ! requirem5ts ( ?is p>ticul> case ^! pole-pieces are out ( l9e ) "o ano!r1 ^? m>k$ ,b surr\nd+ "o end ( ! armature & ! o!rs1 z ,c1 ! opposite end1 & !y are dispos$ alt]nately--t is to say1 ! pole-pieces ( "o set occur 9 l9e ) ! spaces betwe5 ^? ( ! o!r sets4 ,! armature ,d is ( cyl9drical =m1 & is also lam9at$ 9 ! usual way & is w\nd longitud9ally ) coils clos$ ^u !mselves4 ,! pole-pieces ,c are connect$ or %unt$ by bridge-pieces ,e4 ,^! may be made indep5d5tly & atta*$ to ! pole-pieces1 or !y may be p>ts ( ! =ms or blanks /amp$ or pun*$ out ( %eet-iron4 ,_! size or mass is det]m9$ by v>i\s conditions1 su* z ! /r5g? ( ! curr5t to be employ$1 ! mass or size ( ! cores to :i* !y are appli$1 & o!r famili> conditions4 ,coils ,f surr\nd ! pole-pieces ,b1 & o!r coils ,g are w\nd on ! pole-pieces ,c4 ,^! coils are connect$ 9 s]ies 9 two circuits1 :i* are bran*es ( a circuit f a g5]ator ( alt]nat+ curr5ts1 & !y may be s w\nd1 or ! respective circuits 9 :i* !y are includ$ may be s arrang$1 t ! circuit ( coils ,g w h1 indep5d5tly ( ! p>ticul> con/ruction describ$1 a high] self-induction ?an ! o!r circuit or bran*4 ,! function ( ! %unts or bridges ,e is t !y %all =m ) ! cores ,c a clos$ magnetic circuit = a curr5t up to a pr$et]m9$ /r5g?1 s t :5 saturat$ by su* curr5t & unable to c>ry m l9es ( =ce ?an su* a curr5t produces !y w to no fur!r appreciable ext5t int]f]e ) ! developm5t1 by a /rong] curr5t1 ( free magnetic poles at ! ends ( ! cores ,c4 ,9 su* a motor ! curr5t is s ret>d$ 9 ! coils ,g1 & ! manife/ation ( ! free magnetism 9 ! poles ,c is s delay$ beyond ! p]iod ( maximum magnetic effect 9 poles ,b1 t a /rong torque is produc$ & ! motor op]ates ) approximately ! p[] develop$ 9 a motor ( ?is k9d en]giz$ by indep5d5tly g5]at$ curr5ts diff]+ by a full qu>t] phase4 ,,*apt] ,,xiv4 ,,type ,,( ,,tesla ,,s+le-,,phase ,,motor4 ,up to ?is po9t1 two pr9cipal types ( ,tesla motors h be5 describ$3 ,fir/1 ^? conta9+ two or m en]giz+ circuits ?r\gh :i* are caus$ to pass alt]nat+ curr5ts diff]+ f "o ano!r 9 phase to an ext5t suffici5t to produce a cont9u\s progression or %ift+ ( ! poles or po9ts ( greate/ magnetic effect1 9 ob$i5ce to :i* ! movable elem5t ( ! motor is ma9ta9$ 9 rotation2 second1 ^? conta9+ poles1 or p>ts ( diff]5t magnetic susceptibility1 :i* "u ! en]giz+ influ5ce ( ! same curr5t or two curr5ts co9cid+ 9 phase w exhibit diff]5ces 9 _! magnetic p]iods or phases4 ,9 ! fir/ class ( motors ! torque is due to ! magnetism e/abli%$ 9 diff]5t portions ( ! motor by curr5ts f ! same or f indep5d5t s\rces1 & exhibit+ "t diff]5ces 9 phase4 ,9 ! second class ! torque results f ! en]giz+ effects ( a curr5t ^u diff]5t p>ts ( ! motor :i* diff] 9 magnetic susceptibility--9 o!r words1 p>ts :i* respond 9 ! same relative degree to ! action ( a curr5t1 n simultane\sly1 b aft] diff]5t int]vals ( "t4 ,9 ano!r ,tesla motor1 h[ev]1 ! torque1 in/ead ( be+ solely ! result ( a "t diff]5ce 9 ! magnetic p]iods or phases ( ! poles or attractive p>ts to :atev] cause due1 is produc$ by an angul> displacem5t ( ! p>ts :i*1 ?\gh movable ) respect to "o ano!r1 are magnetiz$ simultane\sly1 or approximately s1 by ! same curr5ts4 ,?is pr9ciple ( op]ation has be5 embodi$ practically 9 a motor 9 :i* ! necess>y angul> displacem5t betwe5 ! po9ts ( greate/ magnetic attraction 9 ! two elem5ts ( ! motor--! armature & field--is obta9$ by ! direction ( ! lam9ation ( ! magnetic cores ( ! elem5ts4 ,fig4 #fb is a side view ( su* a motor ) a portion ( its armature core expos$4 ,fig4 #fc is an end or edge view ( ! same4 ,fig4 #fd is a c5tral cross-section ( ! same1 ! armature be+ %[n ma9ly 9 elevation4 ,illu/ration3 ,,fig4 #fb4 ,illu/ration3 ,,fig4 #fc4 ,illu/ration3 ,,fig4 #fd4 ,let ,a ,a designate two plates built up ( ?9 sections or lam9ae ( s(t iron insulat$ m or less f "o ano!r & held toge!r by bolts a & secur$ to a base ,b4 ,! inn] faces ( ^! plates conta9 recesses or grooves 9 :i* a coil or coils ,d are secur$ obliquely to ! direction ( ! lam9ations4 ,)9 ! coils ,d is a disc ,e1 pref]ably compos$ ( a spirally-w\nd iron wire or ribbon or a s]ies ( conc5tric r+s & m\nt$ on a %aft ,f1 hav+ be>+s 9 ! plates ,a ,a4 ,su* a device :5 act$ ^u by an alt]nat+ curr5t is capable ( rotation & con/itutes a motor1 ! op]ation ( :i* may be expla9$ 9 ! foll[+ mann]3 ,a curr5t or curr5t-impulse trav]s+ ! coils ,d t5ds to magnetize ! cores ,a ,a & ,e1 all ( :i* are )9 ! influ5ce ( ! field ( ! coils4 ,! poles ?us e/abli%$ w\ld naturally lie 9 ! same l9e at "r angles to ! coils ,d1 b 9 ! plates ,a !y are deflect$ by reason ( ! direction ( ! lam9ations1 & appe> at or ne> ! extremities ( ^! plates4 ,9 ! disc1 h[ev]1 :]e ^! conditions are n pres5t1 ! poles or po9ts ( greate/ attraction are on a l9e at "r angles to ! plane ( ! coils2 h5ce !re w be a torque e/abli%$ by ?is angul> displacem5t ( ! poles or magnetic l9es1 :i* />ts ! disc 9 rotation1 ! magnetic l9es ( ! armature & field t5d+ t[>d a position ( p>allelism4 ,?is rotation is cont9u$ & ma9ta9$ by ! rev]sals ( ! curr5t 9 coils ,d ,d1 :i* *ange alt]nately ! pol>ity ( ! field-cores ,a ,a4 ,?is rot>y t5d5cy or effect w be greatly increas$ by w9d+ ! disc ) conductors ,g1 clos$ ^u !mselves & hav+ a radial direction1 :]eby ! magnetic int5sity ( ! poles ( ! disc w be greatly increas$ by ! en]giz+ effect ( ! curr5ts induc$ 9 ! coils ,g by ! alt]nat+ curr5ts 9 coils ,d4 ,! cores ( ! disc & field may or may n be ( diff]5t magnetic susceptibility--t is to say1 !y may bo? be ( ! same k9d ( iron1 s z to be magnetiz$ at approximately ! same in/ant by ! coils ,d2 or "o may be ( s(t iron & ! o!r ( h>d1 9 ord] t a c]ta9 "t may elapse betwe5 ! p]iods ( _! magnetization4 ,9 ei!r case rotation w be produc$2 b unless ! disc is provid$ ) ! clos$ en]giz+ coils x is desirable t ! above-describ$ diff]5ce ( magnetic susceptibility be utiliz$ to assi/ 9 its rotation4 ,! cores ( ! field & armature may be made 9 v>i\s ways1 z w be well und]/ood1 x be+ only requisite t ! lam9ations 9 ea* be 9 su* direction z to secure ! necess>y angul> displacem5t ( ! po9ts ( greate/ attraction4 ,moreov]1 s9ce ! disc may be consid]$ z made up ( an inf9ite numb] ( radial arms1 x is obvi\s t :at is true ( a disc holds = _m o!r =ms ( armature4 ,,*apt] ,,xv4 ,,motors ,,) ,,circuits ,,( ,,diff]5t ,,resi/ance4 ,z has be5 po9t$ out else:]e1 ! lag or ret>dation ( ! phases ( an alt]nat+ curr5t is directly proportional to ! self-induction & inv]sely proportional to ! resi/ance ( ! circuit ?r\gh :i* ! curr5t fl[s4 ,h5ce1 9 ord] to secure ! prop] diff]5ces ( phase betwe5 ! two motor-circuits1 x is desirable to make ! self-induction 9 "o mu* high] & ! resi/ance mu* l[] ?an ! self-induction & resi/ance1 respectively1 9 ! o!r4 ,at ! same "t ! magnetic quantities ( ! two poles or sets ( poles :i* ! two circuits produce %\ld be approximately equal4 ,^! requirem5ts h l$ ,mr4 ,tesla to ! inv5tion ( a motor hav+ ! foll[+ g5]al *>act]i/ics3 ,! coils :i* are includ$ 9 t en]giz+ circuit :i* is to h ! high] self-induction are made ( co>se wire1 or a conductor ( relatively l[ resi/ance1 & ) ! greate/ possible l5g? or numb] ( turns4 ,9 ! o!r set ( coils a comp>atively few turns ( f9] wire are us$1 or a wire ( high] resi/ance4 ,fur!rmore1 9 ord] to approximate ! magnetic quantities ( ! poles excit$ by ^! coils1 ,mr4 ,tesla employs 9 ! self-induction circuit cores mu* long] ?an ^? 9 ! o!r or resi/ance circuit4 ,fig4 #fe is a "p sectional view ( ! motor at "r angles to ! %aft4 ,fig4 #ff is a diagram ( ! field circuits4 ,9 ,fig4 #ff1 let ,a repres5t ! coils 9 "o motor circuit1 & ,b ^? 9 ! o!r4 ,! circuit ,a is to h ! high] self-induction4 ,!re are1 !re=e1 us$ a long l5g? or a l>ge numb] ( turns ( co>se wire 9 =m+ ! coils ( ?is circuit4 ,= ! circuit ,b1 a small] conductor is employ$1 or a conductor ( a high] resi/ance ?an copp]1 su* z ,g]man silv] or iron1 & ! coils are w\nd ) few] turns4 ,9 apply+ ^! coils to a motor1 ,mr4 ,tesla builds up a field-magnet ( plates ,c1 ( iron & /eel1 secur$ toge!r 9 ! usual mann] by bolts ,d4 ,ea* plate is =m$ ) f\r 7m or less7 long cores ,e1 ar\nd :i* is a space to receive ! coil & an equal numb] ( %ort projections ,f to receive ! coils ( ! resi/ance-circuit4 ,! plates are g5]ally annul> 9 %ape1 hav+ an op5 space 9 ! c5tre = receiv+ ! armature ,g1 :i* ,mr4 ,tesla pref]s to w9d ) clos$ coils4 ,an alt]nat+ curr5t divid$ betwe5 ! two circuits is ret>d$ z to its phases 9 ! circuit ,a to a mu* great] ext5t ?an 9 ! circuit ,b4 ,by reason ( ! relative sizes & disposition ( ! cores & coils ! magnetic effect ( ! poles ,e & ,f ^u ! armature closely approximate4 ,illu/ration3 ,,fig4 #fe4 ,illu/ration3 ,,fig4 #ff4 ,an important result secur$ by ! con/ruction %[n "h is t ^! coils :i* are design$ to h ! high] self-induction are almo/ completely surr\nd$ by iron1 & t ! ret>dation is ?us v mat]ially increas$4 ,,*apt] ,,xvi4 ,,motor ,,) ,,equal ,,magnetic ,,en]gies ,,9 ,,field ,,& ,,armature4 ,let x be assum$ t ! en]gy z repres5t$ 9 ! magnetism 9 ! field ( a giv5 rotat+ field motor is n9ety & t ( ! armature t54 ,! sum ( ^! quantities1 :i* repres5ts ! total en]gy exp5d$ 9 driv+ ! motor1 is "o hundr$2 b1 assum+ t ! motor be s con/ruct$ t ! en]gy 9 ! field is repres5t$ by fifty1 & t 9 ! armature by fifty1 ! sum is /ill "o hundr$2 b :ile 9 ! fir/ in/ance ! product is n9e hundr$1 9 ! second x is two ?\s& five hundr$1 & z ! en]gy develop$ is 9 proportion to ^! products x is cle> t ^? motors are ! mo/ effici5t--o!r ?+s be+ equal--9 :i* ! magnetic en]gies develop$ 9 ! armature & field are equal4 ,^! results ,mr4 ,tesla obta9s by us+ ! same am\nt ( copp] or amp]e turns 9 bo? elem5ts :5 ! cores ( bo? are equal1 or approximately s1 & ! same curr5t en]gizes bo?2 or 9 cases :]e ! curr5ts 9 "o elem5t are induc$ to ^? ( ! o!r he uses 9 ! induc$ coils an excess ( copp] ov] t 9 ! prim>y elem5t or conductor4 ,illu/ration3 ,,fig4 #fg4 ,! conv5tional figure ( a motor "h introduc$1 ,fig4 #fg1 w give an idea ( ! solution furni%$ by ,mr4 ,tesla = ! specific problem4 ,ref]r+ to ! draw+1 ,a is ! field-magnet1 ,b ! armature1 ,c ! field coils1 & ,d ! armature-coils ( ! motor4 ,g5]ally speak+1 if ! mass ( ! cores ( armature & field be equal1 ! am\nt ( copp] or amp]e turns ( ! en]giz+ coils on bo? %\ld also be equal2 b ^! conditions w be modifi$ 9 diff]5t =ms ( ma*9e4 ,x w be und]/ood t ^! results are mo/ advantage\s :5 exi/+ "u ! conditions pres5t$ :]e ! motor is runn+ ) its normal load1 a po9t to be well borne 9 m9d4 ,,*apt] ,,xvii4 ,,motors ,,) ,,co9cid+ ,,maxima ,,( ,,magnetic ,,effect ,,9 ,,armature ,,& ,,field4 ,9 ?is =m ( motor1 ,mr4 ,tesla's object is to design & build ma*9es :]e9 ! maxima ( ! magnetic effects ( ! armature & field w m ne>ly co9cide ?an 9 "s ( ! types previ\sly "u consid]ation4 ,^! types are3 ,fir/1 motors hav+ two or m en]giz+ circuits ( ! same electrical "*1 & 9 ! op]ation ( :i* ! curr5ts us$ diff] prim>ily 9 phase2 second1 motors ) a plurality ( en]giz+ circuits ( diff]5t electrical "*1 9 or by means ( :i* ! diff]5ce ( phase is produc$ artificially1 &1 ?ird1 motors ) a plurality ( en]giz+ circuits1 ! curr5ts 9 "o be+ induc$ f curr5ts 9 ano!r4 ,consid]+ ! /ructural & op]ative conditions ( any "o ( !m--z1 = example1 t fir/ nam$--! armature :i* is m\nt$ to rotate 9 ob$i5ce to ! co-op]ative influ5ce or action ( ! en]giz+ circuits has coils w\nd ^u x :i* are clos$ ^u !mselves & 9 :i* curr5ts are induc$ by ! en]giz+-curr5ts ) ! object & result ( en]giz+ ! armature-core2 b "u any su* conditions z mu/ exi/ 9 ^! motors1 x is obvi\s t a c]ta9 "t mu/ elapse betwe5 ! manife/ations ( an en]giz+ curr5t impulse 9 ! field coils1 & ! correspond+ magnetic /ate or phase 9 ! armature e/abli%$ by ! curr5t induc$ !reby2 consequ5tly a giv5 magnetic influ5ce or effect 9 ! field :i* is ! direct result ( a prim>y curr5t impulse w h become m or less weak5$ or lo/ be=e ! correspond+ effect 9 ! armature indirectly produc$ has rea*$ its maximum4 ,?is is a condition unfavorable to effici5t work+ 9 c]ta9 cases--z1 = in/ance1 :5 ! progress ( ! resultant poles or po9ts ( maximum attraction is v great1 or :5 a v high numb] ( alt]nations is employ$--= x is app>5t t a /rong] t5d5cy to rotation w be ma9ta9$ if ! maximum magnetic attractions or conditions 9 bo? armature & field co9cide1 ! en]gy develop$ by a motor be+ measur$ by ! product ( ! magnetic quantities ( ! armature & field4 ,to secure ?is co9cid5ce ( maximum magnetic effects1 ,mr4 ,tesla has devis$ v>i\s means1 z expla9$ bel[4 ,fig4 #fh is a diagrammatic illu/ration ( a ,tesla motor sy/em 9 :i* ! alt]nat+ curr5ts proce$ f indep5d5t s\rces & diff] prim>ily 9 phase4 ,illu/ration3 ,,fig4 #fh4 ,illu/ration3 ,,fig4 #fi4 ,a designates ! field-magnet or magnetic frame ( ! motor2 ,b ,b1 oppositely locat$ pole-pieces adapt$ to receive ! coils ( "o en]giz+ circuit2 & ,c ,c1 simil> pole-pieces = ! coils ( ! o!r en]giz+ circuit4 ,^! circuits are designat$1 respectively1 by ,d ,e1 ! conductor ,d'' =m+ a common return to ! g5]ator ,g4 ,betwe5 ^! poles is m\nt$ an armature--= example1 a r+ or annul> armature1 w\nd ) a s]ies ( coils ,f1 =m+ a clos$ circuit or circuits4 ,! action or op]ation ( a motor ?us con/ruct$ is n[ well und]/ood4 ,x w be obs]v$1 h[ev]1 t ! magnetism ( poles ,b1 = example1 e/abli%$ by a curr5t impulse 9 ! coils !reon1 prec$es ! magnetic effect set up 9 ! armature by ! induc$ curr5t 9 coils ,f4 ,consequ5tly ! mutual attraction betwe5 ! armature & field-poles is consid]ably r$uc$4 ,! same conditions w be f\nd to exi/ if1 in/ead ( assum+ ! poles ,b or ,c z act+ indep5d5tly1 we reg>d ! ideal resultant ( bo? act+ toge!r1 :i* is ! real condition4 ,to rem$y ?is1 ! motor field is con/ruct$ ) second>y poles ,b' ,c'1 :i* are situat$ betwe5 ! o!rs4 ,^! pole-pieces are w\nd ) coils ,d' ,e'1 ! =m] 9 d]ivation to ! coils ,d1 ! latt] to coils ,e4 ,! ma9 or prim>y coils ,d & ,e are w\nd = a diff]5t self-induction f t ( ! coils ,d' & ,e'1 ! relations be+ s fix$ t if ! curr5ts 9 ,d & ,e diff]1 = example1 by a qu>t]-phase1 ! curr5ts 9 ea* second>y coil1 z ,d' ,e'1 w diff] f ^? 9 its appropriate prim>y ,d or ,e by1 say1 =ty-five degrees1 or "o-eigh? ( a p]iod4 ,n[1 assum+ t an impulse or alt]nation 9 circuit or bran* ,e is j beg9n+1 :ile 9 ! bran* ,d x is j fall+ f maximum1 ! conditions are ^? ( a qu>t]-phase diff]5ce4 ,! ideal resultant ( ! attractive =ces ( ! two sets ( poles ,b ,c !re=e may be consid]$ z progress+ f poles ,b to poles ,c1 :ile ! impulse 9 ,e is ris+ to maximum1 & t 9 ,d is fall+ to z]o or m9imum4 ,! pol>ity set up 9 ! armature1 h[ev]1 lags beh9d ! manife/ations ( field magnetism1 & h5ce ! maximum po9ts ( attraction 9 armature & field1 in/ead ( co9cid+1 are angul>ly displac$4 ,?is effect is c\nt]act$ by ! supplem5tal poles ,b' ,c'4 ,! magnetic phases ( ^! poles succe$ ^? ( poles ,b ,c by ! same1 or ne>ly ! same1 p]iod ( "t z elapses betwe5 ! effect ( ! poles ,b ,c & ! correspond+ induc$ effect 9 ! armature2 h5ce ! magnetic conditions ( poles ,b' ,c' & ( ! armature m ne>ly co9cide & a bett] result is obta9$4 ,z poles ,b' ,c' act 9 conjunction ) ! poles 9 ! armature e/abli%$ by poles ,b ,c1 s 9 turn poles ,c ,b act simil>ly ) ! poles set up by ,b' ,c'1 respectively4 ,"u su* conditions ! ret>dation ( ! magnetic effect ( ! armature & t ( ! second>y poles w br+ ! maximum ( ! two m ne>ly into co9cid5ce & a correspond+ly /rong] torque or magnetic attraction secur$4 ,9 su* a disposition z is %[n 9 ,fig4 #fh x w be obs]v$ t z ! adjac5t pole-pieces ( ei!r circuit are ( l pol>ity !y w h a c]ta9 weak5+ effect ^u "o ano!r4 ,mr4 ,tesla !re=e pref]s to remove ! second>y poles f ! direct influ5ce ( ! o!rs4 ,?is may be done by con/ruct+ a motor ) two indep5d5t sets ( fields1 & ) ei!r "o or two armatures electrically connect$1 or by us+ two armatures & "o field4 ,^! modifications are illu/rat$ fur!r on4 ,illu/ration3 ,,fig4 #gj4 ,illu/ration3 ,,fig4 #ga4 ,fig4 #fi is a diagrammatic illu/ration ( a motor & sy/em 9 :i* ! diff]5ce ( phase is artificially produc$4 ,!re are two coils ,d ,d 9 "o bran* & two coils ,e ,e 9 ano!r bran* ( ! ma9 circuit f ! g5]ator ,g4 ,^! two circuits or bran*es are ( diff]5t self-induction1 "o1 z ,d1 be+ high] ?an ! o!r4 ,?is is graphically indicat$ by mak+ coils ,d mu* l>g] ?an coils ,e4 ,by reason ( ! diff]5ce 9 ! electrical "* ( ! two circuits1 ! phases ( curr5t 9 "o are ret>d$ to a great] ext5t ?an ! o!r4 ,let ?is diff]5ce be ?irty degrees4 ,a motor ?us con/ruct$ w rotate "u ! action ( an alt]nat+ curr5t2 b z happ5s 9 ! case previ\sly describ$ ! correspond+ magnetic effects ( ! armature & field d n co9cide ow+ to ! "t t elapses betwe5 a giv5 magnetic effect 9 ! armature & ! condition ( ! field t produces x4 ,! second>y or supplem5tal poles ,b' ,c' are !re=e avail$ (4 ,!re be+ ?irty degrees diff]5ce ( phase betwe5 ! curr5ts 9 coils ,d ,e1 ! magnetic effect ( poles ,b' ,c' %\ld correspond to t produc$ by a curr5t diff]+ f ! curr5t 9 coils ,d or ,e by fifte5 degrees4 ,?is we c atta9 by w9d+ ea* supplem5tal pole ,b' ,c' ) two coils ,h ,h'4 ,! coils ,h are includ$ 9 a d]iv$ circuit hav+ ! same self-induction z circuit ,d1 & coils ,h' 9 a circuit hav+ ! same self-induction z circuit ,e1 s t if ^! circuits diff] by ?irty degrees ! magnetism ( poles ,b' ,c' w correspond to t produc$ by a curr5t diff]+ f t 9 ei!r ,d or ,e by fifte5 degrees4 ,?is is true 9 all o!r cases4 ,= example1 if 9 ,fig4 #fh ! coils ,d' ,e' be replac$ by ! coils ,h ,h' includ$ 9 ! d]iv$ circuits1 ! magnetism ( ! poles ,b' ,c' w correspond 9 effect or phase1 if x may be s t]m$1 to t produc$ by a curr5t diff]+ f t 9 ei!r circuit ,d or ,e by =ty-five degrees1 or "o-eigh? ( a p]iod4 ,?is inv5tion z appli$ to a d]iv$ circuit motor is illu/rat$ 9 ,figs4 #gj & #ga4 ,! =m] is an end view ( ! motor ) ! armature 9 section & a diagram ( connections1 & ,fig4 #ga a v]tical section ?r\gh ! field4 ,^! figures are also drawn to %[ "o ( ! dispositions ( two fields t may be adopt$ 9 c>ry+ out ! pr9ciple4 ,! poles ,b ,b ,c ,c are 9 "o field1 ! rema9+ poles 9 ! o!r4 ,! =m] are w\nd ) prim>y coils ,i ,j & second>y coils ,i' ,j'1 ! latt] ) coils ,k ,l4 ,! prim>y coils ,i ,j are 9 d]iv$ circuits1 betwe5 :i*1 by reason ( _! diff]5t self-induction1 !re is a diff]5ce ( phase1 say1 ( ?irty degrees4 ,! coils ,i' ,k are 9 circuit ) "o ano!r1 z also are coils ,j' ,l1 & !re %\ld be a diff]5ce ( phase betwe5 ! curr5ts 9 coils ,k & ,l & _! correspond+ prim>ies (1 say1 fifte5 degrees4 ,if ! poles ,b ,c are at "r angles1 ! armature-coils %\ld be connect$ directly across1 or a s+le armature core w\nd f end to end may be us$2 b if ! poles ,b ,c be 9 l9e !re %\ld be an angul> displacem5t ( ! armature coils1 z w be well und]/ood4 ,! op]ation w be und]/ood f ! =ego+4 ,! maximum magnetic condition ( a pair ( poles1 z ,b' ,b'1 co9cides closely ) ! maximum effect 9 ! armature1 :i* lags beh9d ! correspond+ condition 9 poles ,b ,b4 ,,*apt] ,,xviii4 ,,motor ,,bas$ ,,on ,,! ,,diff]5ce ,,( ,,phase ,,9 ,,! ,,magnetization ,,( ,,! ,,inn] ,,& ,,out] ,,p>ts ,,( ,,an ,,iron ,,core4 ,x is well kn[n t if a magnetic core1 ev5 if lam9at$ or subdivid$1 be w\nd ) an insulat$ coil & a curr5t ( electricity be direct$ ?r\gh ! coil1 ! magnetization ( ! entire core does n imm$iately ensue1 ! magnetiz+ effect n be+ exhibit$ 9 all p>ts simultane\sly4 ,?is may be attribut$ to ! fact t ! action ( ! curr5t is to en]gize fir/ ^? lam9ae or p>ts ( ! core ne>e/ ! surface & adjac5t to ! excit+-coil1 & f !nce ! action progresses t[>d ! int]ior4 ,a c]ta9 int]val ( "t !re=e elapses betwe5 ! manife/ation ( magnetism 9 ! ext]nal & ! int]nal sections or lay]s ( ! core4 ,if ! core be ?9 or ( small mass1 ?is effect may be inappreciable2 b 9 ! case ( a ?ick core1 or ev5 ( a comp>atively ?9 "o1 if ! numb] ( alt]nations or rate ( *ange ( ! curr5t /r5g? be v great1 ! "t int]val occurr+ betwe5 ! manife/ations ( magnetism 9 ! int]ior ( ! core & 9 ^? p>ts adjac5t to ! coil is m m>k$4 ,9 ! con/ruction ( su* app>atus z motors :i* are design$ to be run by alt]nat+ or equival5t curr5ts--su* z pulsat+ or undulat+ curr5ts g5]ally--,mr4 ,tesla f\nd x desirable & ev5 necess>y to give due consid]ation to ?is ph5om5on & to make special provisions 9 ord] to obviate its consequ5ces4 ,) ! specific object ( tak+ advantage ( ?is action or effect1 & to r5d] x m pron\nc$1 he con/ructs a field magnet 9 :i* ! p>ts ( ! core or cores t exhibit at diff]5t int]vals ( "t ! magnetic effect imp>t$ to !m by alt]nat+ or equival5t curr5ts 9 an en]giz+ coil or coils1 are s plac$ ) relation to a rotat+ armature z to ex]t !reon _! attractive effect successively 9 ! ord] ( _! magnetization4 ,by ?is means he secures a result simil> to t :i* he _h previ\sly atta9$ 9 o!r =ms or types ( motor 9 :i* by means ( "o or m alt]nat+ curr5ts he has produc$ ! rotation or progression ( ! magnetic poles4 ,?is new mode ( op]ation w n[ be describ$4 ,fig4 #gb is a side elevation ( su* motor4 ,fig4 #gc is a side elevation ( a m practicable & effici5t embodim5t ( ! inv5tion4 ,fig4 #gd is a c5tral v]tical section ( ! same 9 ! plane ( ! axis ( rotation4 ,illu/ration3 ,,figs4 #gb & #gc4 ,ref]r+ to ,fig4 #gb1 let ,x repres5t a l>ge iron core1 :i* may be compos$ ( a numb] ( %eets or lam9ae ( s(t iron or /eel4 ,surr\nd+ ?is core is a coil ,y1 :i* is connect$ ) a s\rce ,e ( rapidly v>y+ curr5ts4 ,let u consid] n[ ! magnetic conditions exi/+ 9 ?is core at any po9t1 z b1 at or ne> ! c5tre1 & any o!r po9t1 z a1 ne>] ! surface4 ,:5 a curr5t impulse is />t$ 9 ! magnetiz+ coil ,y1 ! section or "p at a1 be+ close to ! coil1 is imm$iately en]giz$1 :ile ! section or "p at b1 :i*1 to use a conv5i5t expression1 is protect$ by ! int]v5+ sections or lay]s betwe5 a & b1 does n at once exhibit its magnetism4 ,h[ev]1 z ! magnetization ( a increases1 b becomes also affect$1 rea*+ f9ally its maximum /r5g? "s "t lat] ?an a4 ,^u ! weak5+ ( ! curr5t ! magnetization ( a fir/ dim9i%es1 :ile b /ill exhibits its maximum /r5g?2 b ! cont9u$ weak5+ ( a is att5d$ by a subsequ5t weak5+ ( b4 ,assum+ ! curr5t to be an alt]nat+ "o1 a w n[ be rev]s$1 :ile b /ill cont9ues ( ! fir/ imp>t$ pol>ity4 ,?is action cont9ues ! magnetic condition ( b1 foll[+ t ( a 9 ! mann] above describ$4 ,if an armature--= in/ance1 a simple disc ,f1 m\nt$ to rotate freely on an axis--be br\ght into proximity to ! core1 a movem5t ( rotation w be imp>t$ to ! disc1 ! direction dep5d+ ^u its position relatively to ! core1 ! t5d5cy be+ to turn ! portion ( ! disc ne>e/ to ! core f a to b1 z indicat$ 9 ,fig4 #gb4 ,illu/ration3 ,,fig4 #gd4 ,?is action or pr9ciple ( op]ation has be5 embodi$ 9 a practicable =m ( motor1 :i* is illu/rat$ 9 ,fig4 #gc4 ,let ,a 9 t figure repres5t a circul> frame ( iron1 f diametrically opposite po9ts ( ! int]ior ( :i* ! cores project4 ,ea* core is compos$ ( ?ree ma9 p>ts ,b1 ,b & ,c1 & !y are simil>ly =m$ ) a /raight portion or body e1 ar\nd :i* ! en]giz+ coil is w\nd1 a curv$ arm or ext5sion c1 & an inw>dly project+ pole or end d4 ,ea* core is made up ( two p>ts ,b ,b1 ) _! pol> ext5sions rea*+ 9 "o direction1 & a "p ,c betwe5 ! o!r two1 & ) its pol> ext5sion rea*+ 9 ! opposite direction4 ,9 ord] to less5 9 ! cores ! circulation ( curr5ts induc$ !re91 ! sev]al sections are insulat$ f "o ano!r 9 ! mann] usually foll[$ 9 su* cases4 ,^! cores are w\nd ) coils ,d1 :i* are connect$ 9 ! same circuit1 ei!r 9 p>allel or s]ies1 & suppli$ ) an alt]nat+ or a pulsat+ curr5t1 pref]ably ! =m]1 by a g5]ator ,e1 repres5t$ diagrammatically4 ,betwe5 ! cores or _! pol> ext5sions is m\nt$ a cyl9drical or simil> armature ,f1 w\nd ) magnetiz+ coils ,g1 clos$ ^u !mselves4 ,! op]ation ( ?is motor is z foll[s3 ,:5 a curr5t impulse or alt]nation is direct$ ?r\gh ! coils ,d1 ! sections ,b ,b ( ! cores1 be+ on ! surface & 9 close proximity to ! coils1 are imm$iately en]giz$4 ,! sections ,c1 on ! o!r h&1 are protect$ f ! magnetiz+ influ5ce ( ! coil by ! int]pos$ lay]s ( iron ,b ,b4 ,z ! magnetism ( ,b ,b increases1 h[ev]1 ! sections ,c are also en]giz$2 b !y d n atta9 _! maximum /r5g? until a c]ta9 "t subsequ5t to ! exhibition by ! sections ,b ,b ( _! maximum4 ,^u ! weak5+ ( ! curr5t ! magnetic /r5g? ( ,b ,b fir/ dim9i%es1 :ile ! sections ,c h /ill _! maximum /r5g?2 b z ,b ,b cont9ue to weak5 ! int]ior sections are simil>ly weak5$4 ,b ,b may !n beg9 to exhibit an opposite pol>ity1 :i* is foll[$ lat] by a simil> *ange on ,c1 & ?is action cont9ues4 ,b ,b & ,c may !re=e be consid]$ z sep>ate field-magnets1 be+ ext5d$ s z to act on ! armature 9 ! mo/ effici5t positions1 & ! effect is simil> to t 9 ! o!r =ms ( ,tesla motor--viz41 a rotation or progression ( ! maximum po9ts ( ! field ( =ce4 ,any armature--su*1 = in/ance1 z a disc--m\nt$ 9 ?is field w\ld rotate f ! pole fir/ to exhibit its magnetism to t :i* exhibits x lat]4 ,x is evid5t t ! pr9ciple "h describ$ may be c>ri$ out 9 conjunction ) o!r means = secur+ a m favorable or effici5t action ( ! motor4 ,= example1 ! pol> ext5sions ( ! sections ,c may be w\nd or surr\nd$ by clos$ coils4 ,! effect ( ^! coils w be to /ill m effectively ret>d ! magnetization ( ! pol> ext5sions ( ,c4 ,,*apt] ,,xix4 ,,ano!r ,,type ,,( ,,tesla ,,induction ,,motor4 ,x w h be5 ga!r$ by all :o are int]e/$ 9 ! advance ( ! electrical arts1 & :o foll[ c>efully1 /ep by /ep1 ! "w ( pione]s1 t ,mr4 ,tesla has be5 =emo/ to utilize inductive effects 9 p]man5tly clos$ circuits1 9 ! op]ation ( alt]nat+ motors4 ,9 ?is *apt] "o simple type ( su* a motor is describ$ & illu/rat$1 :i* w s]ve z an exemplification ( ! pr9ciple4 ,let x be assum$ t an ord9>y alt]nat+ curr5t g5]ator is connect$ up 9 a circuit ( practically no self-induction1 su*1 = example1 z a circuit conta9+ inc&esc5t lamps only4 ,on ! op]ation ( ! ma*9e1 alt]nat+ curr5ts w be develop$ 9 ! circuit1 & ! phases ( ^! curr5ts w !oretically co9cide ) ! phases ( ! impress$ electromotive =ce4 ,su* curr5ts may be reg>d$ & designat$ z ! unret>d$ curr5ts4 ,x w be und]/ood1 ( c\rse1 t 9 practice !re is always m or less self-induction 9 ! circuit1 :i* modifies to a correspond+ ext5t ^! conditions2 b = conv5i5ce ?is may be disreg>d$ 9 ! consid]ation ( ! pr9ciple ( op]ation1 s9ce ! same laws apply4 ,assume next t a pa? ( curr5ts be =m$ across any two po9ts ( ! above circuit1 consi/+1 = example1 ( ! prim>y ( an induction device4 ,! phases ( ! curr5ts pass+ ?r\gh ! prim>y1 ow+ to ! self-induction ( ! same1 w n co9cide ) ! phases ( ! impress$ electromotive =ce1 b w lag beh9d1 su* lag be+ directly proportional to ! self-induction & inv]sely proportional to ! resi/ance ( ! said coil4 ,! ins]tion ( ?is coil w also cause a lagg+ or ret>dation ( ! curr5ts trav]s+ & deliv]$ by ! g5]ator beh9d ! impress$ electromotive =ce1 su* lag be+ ! mean or resultant ( ! lag ( ! curr5t ?r\gh ! prim>y alone & ( ! unret>d$ curr5t 9 ! entire work+ circuit4 ,next consid] ! conditions impos$ by ! association 9 inductive relation ) ! prim>y coil1 ( a second>y coil4 ,! curr5t g5]at$ 9 ! second>y coil w react ^u ! prim>y curr5t1 modify+ ! ret>dation ( ! same1 accord+ to ! am\nt ( self-induction & resi/ance 9 ! second>y circuit4 ,if ! second>y circuit has b little self-induction--z1 = in/ance1 :5 x conta9s inc&esc5t lamps only--x w increase ! actual diff]5ce ( phase betwe5 its own & ! prim>y curr5t1 fir/1 by dim9i%+ ! lag betwe5 ! prim>y curr5t & ! impress$ electromotive =ce1 &1 second1 by its own lag or ret>dation beh9d ! impress$ electromotive =ce4 ,on ! o!r h&1 if ! second>y circuit h a high self-induction1 its lag beh9d ! curr5t 9 ! prim>y is directly increas$1 :ile x w be /ill fur!r increas$ if ! prim>y h a v l[ self-induction4 ,! bett] results are obta9$ :5 ! prim>y has a l[ self-induction4 ,illu/ration3 ,,fig4 #ge4 ,illu/ration3 ,,fig4 #gf4 ,fig4 #ge is a diagram ( a ,tesla motor embody+ ?is pr9ciple4 ,fig4 #gf is a simil> diagram ( a modification ( ! same4 ,9 ,fig4 #ge let ,a designate ! field-magnet ( a motor :i*1 z 9 all ^! motors1 is built up ( sections or plates4 ,b ,c are pol> projections ^u :i* ! coils are w\nd4 ,^u "o pair ( ^! poles1 z ,c1 are w\nd prim>y coils ,d1 :i* are directly connect$ to ! circuit ( an alt]nat+ curr5t g5]ator ,g4 ,on ! same poles are also w\nd second>y coils ,f1 ei!r side by side or ov] or "u ! prim>y coils1 & ^! are connect$ ) o!r coils ,e1 :i* surr\nd ! poles ,b ,b4 ,! curr5ts 9 bo? prim>y & second>y coils 9 su* a motor w be ret>d$ or w lag beh9d ! impress$ electromotive =ce2 b to secure a prop] diff]5ce 9 phase betwe5 ! prim>y & second>y curr5ts !mselves1 ,mr4 ,tesla increases ! resi/ance ( ! circuit ( ! second>y & r$uces z mu* z practicable its self-induction4 ,?is is done by us+ = ! second>y circuit1 p>ticul>ly 9 ! coils ,e1 wire ( comp>atively small diamet] & hav+ b few turns ar\nd ! cores2 or by us+ "s conductor ( high] specific resi/ance1 su* z ,g]man silv]2 or by introduc+ at "s po9t 9 ! second>y circuit an artificial resi/ance ,r4 ,?us ! self-induction ( ! second>y is kept d[n & its resi/ance increas$1 ) ! result ( decreas+ ! lag betwe5 ! impress$ electro-motive =ce & ! curr5t 9 ! prim>y coils & increas+ ! diff]5ce ( phase betwe5 ! prim>y & second>y curr5ts4 ,9 ! disposition %[n 9 ,fig4 #gf1 ! lag 9 ! second>y is increas$ by increas+ ! self-induction ( t circuit1 :ile ! increas+ t5d5cy ( ! prim>y to lag is c\nt]act$ by ins]t+ !re9 a dead resi/ance4 ,! prim>y coils ,d 9 ?is case h a l[ self-induction & high resi/ance1 :ile ! coils ,e ,f1 includ$ 9 ! second>y circuit1 h a high self-induction & l[ resi/ance4 ,?is may be done by ! prop] w9d+ ( ! coils2 or 9 ! circuit includ+ ! second>y coils ,e ,f1 we may introduce a self-induction coil ,s1 :ile 9 ! prim>y circuit f ! g5]ator ,g & includ+ coils ,d1 !re may be ins]t$ a dead resi/ance ,r4 ,by ?is means ! diff]5ce ( phase betwe5 ! prim>y & second>y is increas$4 ,x is evid5t t bo? means ( increas+ ! diff]5ce ( phase--namely1 by ! special w9d+ z well z by ! supplem5tal or ext]nal inductive & dead resi/ance--may be employ$ conjo9tly4 ,9 ! op]ation ( ?is motor ! curr5t impulses 9 ! prim>y coils induce curr5ts 9 ! second>y coils1 & by ! conjo9t action ( ! two ! po9ts ( greate/ magnetic attraction are %ift$ or rotat$4 ,9 practice x is f\nd desirable to w9d ! armature ) clos$ coils 9 :i* curr5ts are induc$ by ! action !reon ( ! prim>ies4 ,,*apt] ,,xx4 ,,comb9ations ,,( ,,syn*roniz+ ,,motor ,,& ,,torque ,,motor4 ,9 ! prec$+ descriptions relative to syn*roniz+ motors & me?ods ( op]at+ !m1 ref]5ce has be5 made to ! plan adopt$ by ,mr4 ,tesla1 :i* consi/s broadly 9 w9d+ or arrang+ ! motor 9 su* mann] t by means ( suitable swit*es x c\ld be />t$ z a multiple-circuit motor1 or "o op]at+ by a progression ( its magnetic poles1 & !n1 :5 up to spe$1 or ne>ly s1 conv]t$ into an ord9>y syn*roniz+ motor1 or "o 9 :i* ! magnetic poles 7 simply alt]nat$4 ,9 "s cases1 z :5 a l>ge motor is us$ & :5 ! numb] ( alt]nations is v high1 !re is m or less difficulty 9 br++ ! motor to spe$ z a d\ble or multiple-circuit motor1 = ! plan ( con/ruction :i* r5d]s ! motor be/ adapt$ to run z a syn*roniz+ motor impairs its effici5cy z a torque or d\ble-circuit motor "u ! assum$ conditions on ! />t4 ,?is w be readily und]/ood1 = 9 a l>ge syn*roniz+ motor ! l5g? ( ! magnetic circuit ( ! pol> projections1 & _! mass1 are s great t app>5tly consid]able "t is requir$ = magnetization & demagnetization4 ,h5ce ) a curr5t ( a v high numb] ( alt]nations ! motor may n respond prop]ly4 ,to avoid ?is objection & to />t up a syn*roniz+ motor 9 :i* ^! conditions obta91 ,mr4 ,tesla has comb9$ two motors1 "o a syn*roniz+ motor1 ! o!r a multiple-circuit or torque motor1 & by ! latt] he br+s ! fir/-nam$ up to spe$1 & !n ei!r ?r[s ! :ole curr5t into ! syn*roniz+ motor or op]ates jo9tly bo? ( ! motors4 ,?is inv5tion involves sev]al novel & useful features4 ,x w be obs]v$1 9 ! fir/ place1 t bo? motors are run1 )\t commutators ( any k9d1 &1 secondly1 t ! spe$ ( ! torque motor may be high] ?an t ( ! syn*roniz+ motor1 z w be ! case :5 x conta9s a few] numb] ( poles or sets ( poles1 s t ! motor w be m readily & easily br\ght up to spe$4 ,?irdly1 ! syn*roniz+ motor may be con/ruct$ s z to h a mu* m pron\nc$ t5d5cy to syn*ronism )\t less5+ ! facility ) :i* x is />t$4 ,fig4 #gg is a "p sectional view ( ! two motors2 ,fig4 #gh an end view ( ! syn*roniz+ motor2 ,fig4 #gi an end view & "p section ( ! torque or d\ble-circuit motor2 ,fig4 #hj a diagram ( ! circuit connections employ$2 & ,figs4 #ha1 #hb1 #hc1 #hd & #he are diagrams ( modifi$ dispositions ( ! two motors4 ,illu/ration3 ,,fig4 #gg4 ,inasmu* z nei!r motor is do+ any "w :ile ! curr5t is act+ ^u ! o!r1 ! two armatures are rigidly connect$1 bo? be+ m\nt$ ^u ! same %aft ,a1 ! field-magnets ,b ( ! syn*roniz+ & ,c ( ! torque motor be+ secur$ to ! same base ,d4 ,! pref]ably l>g] syn*roniz+ motor has pol> projections on its armature1 :i* rotate 9 v close proximity to ! poles ( ! field1 & 9 o!r respects x con=ms to ! conditions t are necess>y to secure syn*ron\s action4 ,! pole-pieces ( ! armature are1 h[ev]1 w\nd ) clos$ coils ,e1 z ?is obviates ! employm5t ( slid+ contacts4 ,! small] or torque motor1 on ! o!r h&1 has1 pref]ably1 a cyl9drical armature ,f1 )\t pol> projections & w\nd ) clos$ coils ,g4 ,! field-coils ( ! torque motor are connect$ up 9 two s]ies ,h & ,i1 & ! alt]nat+ curr5t f ! g5]ator is direct$ ?r\gh or divid$ betwe5 ^! two circuits 9 any mann] to produce a progression ( ! poles or po9ts ( maximum magnetic effect4 ,?is result is secur$ by connect+ ! two motor-circuits 9 d]ivation ) ! circuit f ! g5]ator1 ins]t+ 9 "o motor circuit a dead resi/ance & 9 ! o!r a self-induction coil1 by :i* means a diff]5ce 9 phase betwe5 ! two divisions ( ! curr5t is secur$4 ,if bo? motors h ! same numb] ( field poles1 ! torque motor = a giv5 numb] ( alt]nations w t5d to run at d\ble ! spe$ ( ! o!r1 =1 assum+ ! connections to be su* z to give ! be/ results1 its poles are divid$ into two s]ies & ! numb] ( poles is virtually r$uc$ "o-half1 :i* be+ act$ ^u by ! same numb] ( alt]nations t5d to rotate ! armature at twice ! spe$4 ,by ?is means ! ma9 armature is m easily br\ght to or above ! requir$ spe$4 ,:5 ! spe$ necess>y = syn*ronism is imp>t$ to ! ma9 motor1 ! curr5t is %ift$ f ! torque motor into ! o!r4 ,illu/ration3 ,,fig4 #gh4 ,illu/ration3 ,,fig4 #gi4 ,a conv5i5t arrangem5t = c>ry+ out ?is inv5tion is %[n 9 ,fig4 #hj1 9 :i* ,j ,j are ! field coils ( ! syn*roniz+1 & ,h ,i ! field coils ( ! torque motor4 ,l ,l' are ! conductors ( ! ma9 l9e4 ,"o end (1 say1 coils ,h is connect$ to wire ,l ?r\gh a self-induction coil ,m4 ,"o end ( ! o!r set ( coils ,i is connect$ to ! same wire ?r\gh a dead resi/ance ,n4 ,! opposite ends ( ^! two circuits are connect$ to ! contact m ( a swit*1 ! h&le or lev] ( :i* is 9 connection ) ! l9e-wire ,l'4 ,"o end ( ! field circuit ( ! syn*roniz+ motor is connect$ to ! wire ,l4 ,! o!r t]m9ates 9 ! swit*-contact n4 ,f ! diagram x w be readily se5 t if ! lev] ,p be turn$ ^u contact m1 ! torque motor w />t by reason ( ! diff]5ce ( phase betwe5 ! curr5ts 9 its two en]giz+ circuits4 ,!n :5 ! desir$ spe$ is atta9$1 if ! lev] ,p be %ift$ ^u contact n ! entire curr5t w pass ?r\gh ! field coils ( ! syn*roniz+ motor & ! o!r w be do+ no "w4 ,! torque motor may be con/ruct$ & op]at$ 9 v>i\s ways1 _m ( :i* h already be5 t\*$ ^u4 ,x is n necess>y t "o motor be cut out ( circuit :ile ! o!r is 91 = bo? may be act$ ^u by curr5t at ! same "t1 & ,mr4 ,tesla has devis$ v>i\s dispositions or arrangem5ts ( ! two motors = accompli%+ ?is4 ,"s ( ^! arrangem5ts are illu/rat$ 9 ,figs4 #ha to #he4 ,illu/ration3 ,,fig4 #hj4 ,ref]r+ to ,fig4 #ha1 let ,t designate ! torque or multiple circuit motor & ,s ! syn*roniz+ motor1 ,l ,l' be+ ! l9e-wires f a s\rce ( alt]nat+ curr5t4 ,! two circuits ( ! torque motor ( diff]5t degrees ( self-induction1 & designat$ by ,n ,m1 are connect$ 9 d]ivation to ! wire ,l4 ,!y are !n jo9$ & connect$ to ! en]giz+ circuit ( ! syn*roniz+ motor1 ! opposite t]m9al ( :i* is connect$ to wire ,l'4 ,! two motors are ?us 9 s]ies4 ,to />t !m ,mr4 ,tesla %ort-circuits ! syn*roniz+ motor by a swit* ,p'1 ?r[+ ! :ole curr5t ?r\gh ! torque motor4 ,!n :5 ! desir$ spe$ is rea*$ ! swit* ,p' is op5$1 s t ! curr5t passes ?r\gh bo? motors4 ,9 su* an arrangem5t z ?is x is obvi\sly desirable = economical & o!r reasons t a prop] relation betwe5 ! spe$s ( ! two motors %\ld be obs]v$4 ,9 ,fig4 #hb ano!r disposition is illu/rat$4 ,s is ! syn*roniz+ motor & ,t ! torque motor1 ! circuits ( bo? be+ 9 p>allel4 ,w is a circuit also 9 d]ivation to ! motor circuits & conta9+ a swit* ,p''4 ,s' is a swit* 9 ! syn*roniz+ motor circuit4 ,on ! />t ! swit* ,s' is op5$1 cutt+ out ! motor ,s4 ,!n ,p'' is op5$1 ?r[+ ! entire curr5t ?r\gh ! motor ,t1 giv+ x a v /rong torque4 ,:5 ! desir$ spe$ is rea*$1 swit* ,s' is clos$ & ! curr5t divides betwe5 bo? motors4 ,by means ( swit* ,p'' bo? motors may be cut out4 ,illu/ration3 ,,figs4 #ha1 #hb1 #hc1 #hd & #he4 ,9 ,fig4 #hc ! arrangem5t is sub/antially ! same1 except t a swit* ,t' is plac$ 9 ! circuit :i* includes ! two circuits ( ! torque motor4 ,fig4 #hd %[s ! two motors 9 s]ies1 ) a %unt ar\nd bo? conta9+ a swit* ,s ,t4 ,!re is also a %unt ar\nd ! syn*roniz+ motor ,s1 ) a swit* ,p'4 ,9 ,fig4 #he ! same disposition is %[n2 b ea* motor is provid$ ) a %unt1 9 :i* are swit*es ,p' & ,t''1 z %[n4 ,,*apt] ,,xxi4 ,,motor ,,) ,a ,,cond5s] ,,9 ,,! ,,armature ,,circuit4 ,we n[ come to a new class ( motors 9 :i* resort is _h to cond5s]s = ! purpose ( develop+ ! requir$ diff]5ce ( phase & neutraliz+ ! effects ( self-induction4 ,mr4 ,tesla e>ly began to apply ! cond5s] to alt]nat+ app>atus1 9 j h[ _m ways c only be le>n$ f a p]usal ( o!r portions ( ?is volume1 especially ^? deal+ ) 8 high frequ5cy "w4 ,c]ta9 laws gov]n ! action or effects produc$ by a cond5s] :5 connect$ to an electric circuit ?r\gh :i* an alt]nat+ or 9 g5]al an undulat+ curr5t is made to pass4 ,"s ( ! mo/ important ( su* effects are z foll[s3 ,fir/1 if ! t]m9als or plates ( a cond5s] be connect$ ) two po9ts ( a circuit1 ! pot5tials ( :i* are made to rise & fall 9 rapid succession1 ! cond5s] all[s ! passage1 or m /rictly speak+1 ! transf]5ce ( a curr5t1 al?\gh its plates or armatures may be s c>efully insulat$ z to prev5t almo/ completely ! passage ( a curr5t ( unv>y+ /r5g? or direction & ( mod]ate electromotive =ce4 ,second1 if a circuit1 ! t]m9als ( :i* are connect$ ) ! plates ( ! cond5s]1 possess a c]ta9 self-induction1 ! cond5s] w ov]come or c\nt]act to a great] or less degree1 dep5d5t ^u well-und]/ood conditions1 ! effects ( su* self-induction4 ,?ird1 if two po9ts ( a clos$ or complete circuit ?r\gh :i* a rapidly ris+ & fall+ curr5t fl[s be %unt$ or bridg$ by a cond5s]1 a v>iation 9 ! /r5g? ( ! curr5ts 9 ! bran*es & also a diff]5ce ( phase ( ! curr5ts !re9 is produc$4 ,^! effects ,mr4 ,tesla has utiliz$ & appli$ 9 a v>iety ( ways 9 ! con/ruction & op]ation ( 8 motors1 su* z by produc+ a diff]5ce 9 phase 9 ! two en]giz+ circuits ( an alt]nat+ curr5t motor by connect+ ! two circuits 9 d]ivation & connect+ up a cond5s] 9 s]ies 9 "o ( ! circuits4 ,a fur!r developm5t1 h[ev]1 possesses c]ta9 novel features ( practical value & involves a k ( facts less g5]ally und]/ood4 ,x comprises ! use ( a cond5s] or cond5s]s 9 connection ) ! induc$ or armature circuit ( a motor & c]ta9 details ( ! con/ruction ( su* motors4 ,9 an alt]nat+ curr5t motor ( ! type p>ticul>ly ref]r$ to above1 or 9 any o!r :i* has an armature coil or circuit clos$ ^u itself1 ! latt] repres5ts n only an inductive resi/ance1 b "o :i* is p]iodically v>y+ 9 value1 bo? ( :i* facts complicate & r5d] difficult ! atta9m5t ( ! conditions be/ suit$ to ! mo/ effici5t work+ conditions2 9 o!r words1 !y require1 fir/1 t = a giv5 inductive effect ^u ! armature !re %\ld be ! greate/ possible curr5t ?r\gh ! armature or induc$ coils1 &1 second1 t !re %\ld always exi/ betwe5 ! curr5ts 9 ! en]giz+ & ! induc$ circuits a giv5 relation ( phase4 ,h5ce :atev] t5ds to decrease ! self-induction & increase ! curr5t 9 ! induc$ circuits w1 o!r ?+s be+ equal1 increase ! output & effici5cy ( ! motor1 & ! same w be true ( causes t op]ate to ma9ta9 ! mutual attractive effect betwe5 ! field magnets & armature at its maximum4 ,mr4 ,tesla secures ^! results by connect+ ) ! induc$ circuit or circuits a cond5s]1 9 ! mann] describ$ bel[1 & he also1 ) ?is purpose 9 view1 con/ructs ! motor 9 a special mann]4 ,illu/ration3 ,,fig4 #hf4 ,illu/ration3 ,,fig4 #hh4 ,illu/ration3 ,,fig4 #hi4 ,illu/ration3 ,,fig4 #hg4 ,illu/ration3 ,,fig4 #ij4 ,ref]r+ to ! draw+s1 ,fig4 #hf1 is a view1 ma9ly diagrammatic1 ( an alt]nat+ curr5t motor1 9 :i* ! pres5t pr9ciple is appli$4 ,fig4 #hg is a c5tral section1 9 l9e ) ! %aft1 ( a special =m ( armature core4 ,fig4 #hh is a simil> section ( a modification ( ! same4 ,fig4 #hi is "o ( ! sections ( ! core deta*$4 ,fig4 #ij is a diagram %[+ a modifi$ disposition ( ! armature or induc$ circuits4 ,! g5]al plan ( ! inv5tion is illu/rat$ 9 ,fig4 #hf4 ,a ,a 9 ?is figure repres5t ! ! frame & field magnets ( an alt]nat+ curr5t motor1 ! poles or projections ( :i* are w\nd ) coils ,b & ,c1 =m+ indep5d5t en]giz+ circuits connect$ ei!r to ! same or to indep5d5t s\rces ( alt]nat+ curr5ts1 s t ! curr5ts fl[+ ?r\gh ! circuits1 respectively1 w h a diff]5ce ( phase4 ,)9 ! influ5ce ( ?is field is an armature core ,d1 w\nd ) coils ,e4 ,9 motors ( ?is description h]et(ore ^! coils h be5 clos$ ^u !mselves1 or connect$ 9 a clos$ s]ies2 b 9 ! pres5t case ea* coil or ! connect$ s]ies ( coils t]m9ates 9 ! opposite plates ( a cond5s] ,f4 ,= ?is purpose ! ends ( ! s]ies ( coils are br\ght out ?r\gh ! %aft to collect+ r+s ,g1 :i* are connect$ to ! cond5s] by contact bru%es ,h & suitable conductors1 ! cond5s] be+ indep5d5t ( ! ma*9e4 ,! armature coils are w\nd or connect$ 9 su* mann] t adjac5t coils produce opposite poles4 ,! action ( ?is motor & ! effect ( ! plan foll[$ 9 its con/ruction are z foll[s3 ,! motor be+ />t$ 9 op]ation & ! coils ( ! field magnets be+ trav]s$ by alt]nat+ curr5ts1 curr5ts are induc$ 9 ! armature coils by "o set ( field coils1 z ,b1 & ! poles ?us e/abli%$ are act$ ^u by ! o!r set1 z ,c4 ,! armature coils1 h[ev]1 h necess>ily a high self-induction1 :i* opposes ! fl[ ( ! curr5ts ?us set up4 ,! cond5s] ,f n only p]mits ! passage or transf]5ce ( ^! curr5ts1 b also c\nt]acts ! effects ( self-induction1 & by a prop] adju/m5t ( ! capacity ( ! cond5s]1 ! self-induction ( ! coils1 & ! p]iods ( ! curr5ts1 ! cond5s] may be made to ov]come entirely ! effect ( self-induction4 ,x is pref]able on acc\nt ( ! undesirability ( us+ slid+ contacts ( any k9d1 to associate ! cond5s] ) ! armature directly1 or make x a "p ( ! armature4 ,9 "s cases ,mr4 ,tesla builds up ! armature ( annul> plates ,k ,k1 held by bolts ,l betwe5 heads ,m1 :i* are secur$ to ! driv+ %aft1 & 9 ! holl[ space ?us =m$ he places a cond5s] ,f1 g5]ally by w9d+ ! two insulat$ plates spirally ar\nd ! %aft4 ,9 o!r cases he utilizes ! plates ( ! core itself z ! plates ( ! cond5s]4 ,= example1 9 ,figs4 #hh & #hi1 ,n is ! driv+ %aft1 ,m ,m are ! heads ( ! armature-core1 & ,k ,k' ! iron plates ( :i* ! core is built up4 ,^! plates are insulat$ f ! %aft & f "o ano!r1 & are held toge!r by rods or bolts ,l4 ,! bolts pass ?r\gh a l>ge hole 9 "o plate & a small hole 9 ! "o next adjac5t1 & s on1 connect+ electrically all ( plates ,k1 z "o armature ( a cond5s]1 & all ( plates ,k' z ! o!r4 ,to ei!r ( ! cond5s]s above describ$ ! armature coils may be connect$1 z expla9$ by ref]5ce to ,fig4 #hf4 ,9 motors 9 :i* ! armature coils are clos$ ^u !mselves--z1 = example1 9 any =m ( alt]nat+ curr5t motor 9 :i* "o armature coil or set ( coils is 9 ! position ( maximum induction ) respect to ! field coils or poles1 :ile ! o!r is 9 ! position ( m9imum induction--! coils are be/ connect$ 9 "o s]ies1 & two po9ts ( ! circuit ?us =m$ are bridg$ by a cond5s]4 ,?is is illu/rat$ 9 ,fig4 #ij1 9 :i* ,e repres5ts "o set ( armature coils & ,e' ! o!r4 ,_! po9ts ( union are jo9$ ?r\gh a cond5s] ,f4 ,x w be obs]v$ t 9 ?is disposition ! self-induction ( ! two bran*es ,e & ,e' v>ies ) _! position relatively to ! field magnet1 & t ea* bran* is alt]nately ! pr$om9at+ s\rce ( ! induc$ curr5t4 ,h5ce ! effect ( ! cond5s] ,f is tw(old4 ,fir/1 x increases ! curr5t 9 ea* ( ! bran*es alt]nately1 &1 secondly1 x alt]s ! phase ( ! curr5ts 9 ! bran*es1 ?is be+ ! well-kn[n effect :i* results f su* a disposition ( a cond5s] ) a circuit1 z above describ$4 ,?is effect is favorable to ! prop] work+ ( ! motor1 because x increases ! fl[ ( curr5t 9 ! armature circuits due to a giv5 inductive effect1 & also because x br+s m ne>ly into co9cid5ce ! maximum magnetic effects ( ! coact+ field & armature poles4 ,x w be und]/ood1 ( c\rse1 t ! causes t contribute to ! effici5cy ( cond5s]s :5 appli$ to su* uses z ! above mu/ be giv5 due consid]ation 9 det]m9+ ! practicability & effici5cy ( ! motors4 ,*ief among ^! is1 z is well kn[n1 ! p]iodicity ( ! curr5t1 & h5ce ! improvem5ts describ$ are m p>ticul>ly adapt$ to sy/ems 9 :i* a v high rate ( alt]nation or *ange is ma9ta9$4 ,al?\gh ?is inv5tion has be5 illu/rat$ 9 connection ) a special =m ( motor1 x w be und]/ood t x is equally applicable to any o!r alt]nat+ curr5t motor 9 :i* !re is a clos$ armature coil :]e9 ! curr5ts are induc$ by ! action ( ! field1 & ! feature ( utiliz+ ! plates or sections ( a magnetic core = =m+ ! cond5s] is applicable1 g5]ally1 to o!r k9ds ( alt]nat+ curr5t app>atus4 ,,*apt] ,,xxii4 ,,motor ,,) ,,cond5s] ,,9 ,,"o ,,( ,,! ,,field ,,circuits4 ,if ! field or en]giz+ circuits ( a rot>y phase motor be bo? d]iv$ f ! same s\rce ( alt]nat+ curr5ts & a cond5s] ( prop] capacity be includ$ 9 "o ( ! same1 approximately1 ! desir$ diff]5ce ( phase may be obta9$ betwe5 ! curr5ts fl[+ directly f ! s\rce & ^? fl[+ ?r\gh ! cond5s]2 b ! great size & exp5se ( cond5s]s = ?is purpose t w\ld meet ! requirem5ts ( ! ord9>y sy/ems ( comp>atively l[ pot5tial are p>ticul>ly prohibitory to _! employm5t4 ,ano!r1 n[ well-kn[n1 me?od or plan ( secur+ a diff]5ce ( phase betwe5 ! en]giz+ curr5ts ( motors ( ?is k9d is to induce by ! curr5ts 9 "o circuit ^? 9 ! o!r circuit or circuits2 b z no means _h be5 propos$ t w\ld secure 9 ?is way betwe5 ! phases ( ! prim>y or induc+ & ! second>y or induc$ curr5ts t diff]5ce--!oretically n9ety degrees--t is be/ adapt$ = practical & economical work+1 ,mr4 ,tesla devis$ a means :i* r5d]s practicable bo? ! above describ$ plans or me?ods1 & by :i* he is enabl$ to obta9 an economical & effici5t alt]nat+ curr5t motor4 ,8 inv5tion consi/s 9 plac+ a cond5s] 9 ! second>y or induc$ circuit ( ! motor above describ$ & rais+ ! pot5tial ( ! second>y curr5ts to su* a degree t ! capacity ( ! cond5s]1 :i* is 9 "p dep5d5t on ! pot5tial1 ne$ be q small4 ,! value ( ?is cond5s] is det]m9$ 9 a well-und]/ood mann] ) ref]5ce to ! self-induction & o!r conditions ( ! circuit1 s z to cause ! curr5ts :i* pass ?r\gh x to diff] f ! prim>y curr5ts by a qu>t] phase4 ,fig4 #ia illu/rates ! inv5tion z embodi$ 9 a motor 9 :i* ! inductive relation ( ! prim>y & second>y circuits is secur$ by w9d+ !m inside ! motor p>tly ^u ! same cores2 b ! inv5tion applies1 g5]ally1 to o!r =ms ( motor 9 :i* "o ( ! en]giz+ curr5ts is induc$ 9 any way f ! o!r4 ,let ,a ,b repres5t ! poles ( an alt]nat+ curr5t motor1 ( :i* ,c is ! armature w\nd ) coils ,d1 clos$ ^u !mselves1 z is n[ ! g5]al practice 9 motors ( ?is k9d4 ,! poles ,a1 :i* alt]nate ) poles ,b1 are w\nd ) coils ( ord9>y or co>se wire ,e 9 su* direction z to make !m ( alt]nate nor? & s\? pol>ity1 z indicat$ 9 ! diagram by ! *>act]s ,n ,s4 ,ov] ^! coils1 or 9 o!r inductive relation to ! same1 are w\nd long f9e-wire coils ,f ,f1 & 9 ! same direction ?r\gh\t z ! coils ,e4 ,^! coils are second>ies1 9 :i* curr5ts ( v high pot5tial are induc$4 ,all ! coils ,e 9 "o s]ies are connect$1 & all ! second>ies ,f 9 ano!r4 ,illu/ration3 ,,fig4 #ia4 ,on ! int]m$iate poles ,b are w\nd f9e-wire en]giz+ coils ,g1 :i* are connect$ 9 s]ies ) "o ano!r1 & also ) ! s]ies ( second>y coils ,f1 ! direction ( w9d+ be+ su* t a curr5t-impulse induc$ f ! prim>y coils ,e imp>ts ! same magnetism to ! poles ,b z t produc$ 9 poles ,a by ! prim>y impulse4 ,?is condition is indicat$ by ! *>act]s ,n' ,s'4 ,9 ! circuit =m$ by ! two sets ( coils ,f & ,g is introduc$ a cond5s] ,h2 o!rwise ?is circuit is clos$ ^u itself1 :ile ! free ends ( ! circuit ( coils ,e are connect$ to a s\rce ( alt]nat+ curr5ts4 ,z ! cond5s] capacity :i* is ne$$ 9 any p>ticul> motor ( ?is k9d is dep5d5t ^u ! rate ( alt]nation or ! pot5tial1 or bo?1 its size or co/1 z be=e expla9$1 may be br\ght )9 economical limits = use ) ! ord9>y circuits if ! pot5tial ( ! second>y circuit 9 ! motor be suffici5tly high4 ,by giv+ to ! cond5s] prop] values1 any desir$ diff]5ce ( phase betwe5 ! prim>y & second>y en]giz+ circuits may be obta9$4 ,,*apt] ,,xxiii4 ,,tesla ,,polyphase ,,trans=m]4 ,apply+ ! polyphase pr9ciple to ! con/ruction ( trans=m]s z well to ! motors already notic$1 ,mr4 ,tesla has inv5t$ "s v int]e/+ =ms1 :i* he consid]s free f ! defects ( e>li] &1 at pres5t1 m famili> =ms4 ,9 ^! trans=m]s he provides a s]ies ( induc+ coils & correspond+ induc$ coils1 :i* are g5]ally w\nd ^u a core clos$ ^u itself1 usually a r+ ( lam9at$ iron4 ,! two sets ( coils are w\nd side by side or sup]pos$ or o!rwise plac$ 9 well-kn[n ways to br+ !m into ! mo/ effective relations to "o ano!r & to ! core4 ,! induc+ or prim>y coils w\nd on ! core are divid$ into pairs or sets by ! prop] electrical connections1 s t :ile ! coils ( "o pair or set co-op]ate 9 fix+ ! magnetic poles ( ! core at two giv5 diametrically opposite po9ts1 ! coils ( ! o!r pair or set--assum+1 = sake ( illu/ration1 t !re are b two--t5d to fix ! poles n9ety degrees f su* po9ts4 ,) ?is induction device is us$ an alt]nat+ curr5t g5]ator ) coils or sets ( coils to correspond ) ^? ( ! conv]t]1 & ! correspond+ coils ( ! g5]ator & conv]t] are !n connect$ up 9 indep5d5t circuits4 ,x results f ?is t ! diff]5t electrical phases 9 ! g5]ator are att5d$ by correspond+ magnetic *anges 9 ! conv]t]2 or1 9 o!r words1 t z ! g5]ator coils revolve1 ! po9ts ( greate/ magnetic int5sity 9 ! conv]t] w be progressively %ift$ or :irl$ ar\nd4 ,fig4 #ib is a diagrammatic illu/ration ( ! conv]t] & ! electrical connections ( ! same4 ,fig4 #ic is a horizontal c5tral cross-section ( ,fig4 #ib4 ,fig4 #id is a diagram ( ! circuits ( ! entire sy/em1 ! g5]ator be+ %[n 9 section4 ,mr4 ,tesla uses a core1 ,a1 :i* is clos$ ^u itself--t is to say1 ( an annul> cyl9drical or equival5t =m--& z ! effici5cy ( ! app>atus is l>gely increas$ by ! subdivision ( ?is core1 he makes x ( ?9 /rips1 plates1 or wires ( s(t iron electrically insulat$ z f> z practicable4 ,^u ?is core are w\nd1 say1 f\r coils1 ,b ,b ,b' ,b'1 us$ z prim>y coils1 & = :i* long l5g?s ( comp>atively f9e wire are employ$4 ,ov] ^! coils are !n w\nd %ort] coils ( co>s] wire1 ,c ,c ,c' ,c'1 to con/itute ! induc$ or second>y coils4 ,! con/ruction ( ?is or any equival5t =m ( conv]t] may be c>ri$ fur!r1 z above po9t$ out1 by inclos+ ^! coils ) iron--z1 = example1 by w9d+ ov] ! coils lay]s ( insulat$ iron wire4 ,illu/ration3 ,,figs4 #ib & #ic4 ,illu/ration3 ,,fig4 #id4 ,! device is provid$ ) suitable b9d+ po/s1 to :i* ! ends ( ! coils are l$4 ,! diametrically opposite coils ,b ,b & ,b' ,b' are connect$1 respectively1 9 s]ies1 & ! f\r t]m9als are connect$ to ! b9d+ po/s4 ,! induc$ coils are connect$ toge!r 9 any desir$ mann]4 ,= example1 z %[n 9 ,fig4 #id1 ,c ,c may be connect$ 9 multiple arc :5 a quantity curr5t is desir$--z = runn+ a gr\p ( inc&esc5t lamps--:ile ,c' ,c' may be indep5d5tly connect$ 9 s]ies 9 a circuit includ+ arc lamps or ! l4 ,! g5]ator 9 ?is sy/em w be adapt$ to ! conv]t] 9 ! mann] illu/rat$4 ,= example1 9 ! pres5t case !re are employ$ a pair ( ord9>y p]man5t or electro-magnets1 ,e ,e1 betwe5 :i* is m\nt$ a cyl9drical armature on a %aft1 ,f1 & w\nd ) two coils1 ,g ,g'4 ,! t]m9als ( ^! coils are connect$1 respectively1 to f\r insulat$ contact or collect+ r+s1 ,h ,h ,h' ,h'1 & ! f\r l9e circuit wires ,l connect ! bru%es ,k1 be>+ on ^! r+s1 to ! conv]t] 9 ! ord] %[n4 ,not+ ! results ( ?is comb9ation1 x w be obs]v$ t at a giv5 po9t ( "t ! coil ,g is 9 its neutral position & is g5]at+ little or no curr5t1 :ile ! o!r coil1 ,g'1 is 9 a position :]e x ex]ts its maximum effect4 ,assum+ coil ,g to be connect$ 9 circuit ) coils ,b ,b ( ! conv]t]1 & coil ,g' ) coils ,b' ,b'1 x is evid5t t ! poles ( ! r+ ,a w be det]m9$ by coils ,b' ,b' alone2 b z ! armature ( ! g5]ator revolves1 coil ,g develops m curr5t & coil ,g' less1 until ,g rea*es its maximum & ,g' its neutral position4 ,! obvi\s result w be to %ift ! poles ( ! r+ ,a ?r\gh "o-qu>t] ( its p]iph]y4 ,! movem5t ( ! coils ?r\gh ! next qu>t] ( a turn--dur+ :i* coil ,g' ent]s a field ( opposite pol>ity & g5]ates a curr5t ( opposite direction & increas+ /r5g?1 :ile coil ,g1 9 pass+ f its maximum to its neutral position g5]ates a curr5t ( decreas+ /r5g? & same direction z be=e--causes a fur!r %ift+ ( ! poles ?r\gh ! second qu>t] ( ! r+4 ,! second half-revolution w obvi\sly be a repetition ( ! same action4 ,by ! %ift+ ( ! poles ( ! r+ ,a1 a p[]ful dynamic inductive effect on ! coils ,c ,c' is produc$4 ,besides ! curr5ts g5]at$ 9 ! second>y coils by dynamo-magnetic induction1 o!r curr5ts w be set up 9 ! same coils 9 consequ5ce ( _m v>iations 9 ! int5sity ( ! poles 9 ! r+ ,a4 ,?is %\ld be avoid$ by ma9ta9+ ! int5sity ( ! poles con/ant1 to accompli% :i* c>e %\ld be tak5 9 design+ & proportion+ ! g5]ator & 9 di/ribut+ ! coils 9 ! r+ ,a1 & balanc+ _! effect4 ,:5 ?is is done1 ! curr5ts are produc$ by dynamo-magnetic induction only1 ! same result be+ obta9$ z ?\gh ! poles 7 %ift$ by a commutator ) an inf9ite numb] ( segm5ts4 ,! modifications :i* are applicable to o!r =ms ( conv]t] are 9 _m respects applicable to ?is1 su* z ^? p]ta9+ m p>ticul>ly to ! =m ( ! core1 ! relative l5g?s & resi/ances ( ! prim>y & second>y coils1 & ! arrangem5ts = runn+ or op]at+ ! same4 ,,*apt] ,,xxiv4 ,a ,,con/ant ,,curr5t ,,trans=m] ,,) ,,magnetic ,,%ield ,,betwe5 ,,coils ,,( ,,prim>y ,,& ,,second>y4 ,mr4 ,tesla has appli$ 8 pr9ciple ( magnetic %ield+ ( p>ts to ! con/ruction also ( trans=m]s1 ! %ield be+ int]pos$ betwe5 ! prim>y & second>y coils4 ,9 trans=m]s ( ! ord9>y type x w be f\nd t ! wave ( electromotive =ce ( ! second>y v ne>ly co9cides ) t ( ! prim>y1 be+1 h[ev]1 9 opposite sign4 ,at ! same "t ! curr5ts1 bo? prim>y & second>y1 lag beh9d _! respective electromotive =ces2 b z ?is lag is practically or ne>ly ! same 9 ! case ( ea* x foll[s t ! maximum & m9imum ( ! prim>y & second>y curr5ts w ne>ly co9cide1 b diff] 9 sign or direction1 provid$ ! second>y be n load$ or if x conta9 devices hav+ ! prop]ty ( self-induction4 ,on ! o!r h&1 ! lag ( ! prim>y beh9d ! impress$ electromotive =ce may be dim9i%$ by load+ ! second>y ) a non-inductive or dead resi/ance--su* z inc&esc5t lamps--:]eby ! "t int]val betwe5 ! maximum or m9imum p]iods ( ! prim>y & second>y curr5ts is increas$4 ,?is "t int]val1 h[ev]1 is limit$1 & ! results obta9$ by phase diff]5ce 9 ! op]ation ( su* devices z ! ,tesla alt]nat+ curr5t motors c only be approximately realiz$ by su* means ( produc+ or secur+ ?is diff]5ce1 z above indicat$1 = x is desirable 9 su* cases t !re %\ld exi/ betwe5 ! prim>y & second>y curr5ts1 or ^? :i*1 h[ev] produc$1 pass ?r\gh ! two circuits ( ! motor1 a diff]5ce ( phase ( n9ety degrees2 or1 9 o!r words1 ! curr5t 9 "o circuit %\ld be a maximum :5 t 9 ! o!r circuit is a m9imum4 ,to atta9 to ?is condition m p]fectly1 an increas$ ret>dation ( ! second>y curr5t is secur$ 9 ! foll[+ mann]3 ,in/ead ( br++ ! prim>y & second>y coils or circuits ( a trans=m] into ! close/ possible relations1 z has hi!rto be5 done1 ,mr4 ,tesla protects 9 a measure ! second>y f ! inductive action or effect ( ! prim>y by surr\nd+ ei!r ! prim>y or ! second>y ) a comp>atively ?9 magnetic %ield or scre54 ,"u ^! modifi$ conditions1 z long z ! prim>y curr5t has a small value1 ! %ield protects ! second>y2 b z soon z ! prim>y curr5t has rea*$ a c]ta9 /r5g?1 :i* is arbitr>ily det]m9$1 ! protect+ magnetic %ield becomes saturat$ & ! inductive action ^u ! second>y beg9s4 ,x results1 !re=e1 t ! second>y curr5t beg9s to fl[ at a c]ta9 fraction ( a p]iod lat] ?an x w\ld )\t ! int]pos$ %ield1 & s9ce ?is ret>dation may be obta9$ )\t necess>ily ret>d+ ! prim>y curr5t also1 an additional lag is secur$1 & ! "t int]val betwe5 ! maximum or m9imum p]iods ( ! prim>y & second>y curr5ts is increas$4 ,su* a trans=m] may1 by prop]ly proportion+ its sev]al elem5ts & det]m9+ ! prop] relations betwe5 ! prim>y & second>y w9d+s1 ! ?ickness ( ! magnetic %ield1 & o!r conditions1 be con/ruct$ to yield a con/ant curr5t at all loads4 ,illu/ration3 ,,fig4 #ie4 ,fig4 #ie is a cross-section ( a trans=m] embody+ ?is improvem5t4 ,fig4 #if is a simil> view ( a modifi$ =m ( trans=m]1 %[+ diagrammatically ! mann] ( us+ ! same4 ,a ,a is ! ma9 core ( ! trans=m]1 compos$ ( a r+ ( s(t anneal$ & insulat$ or oxidiz$ iron wire4 ,^u ?is core is w\nd ! second>y circuit or coil ,b ,b4 ,?is latt] is !n cov]$ ) a lay] or lay]s ( anneal$ & insulat$ iron wires ,c ,c1 w\nd 9 a direction at "r angles to ! second>y coil4 ,ov] ! :ole is !n w\nd ! prim>y coil or wire ,d ,d4 ,f ! nature ( ?is con/ruction x w be obvi\s t z long z ! %ield =m$ by ! wires ,c is bel[ magnetic saturation ! second>y coil or circuit is effectually protect$ or %ield$ f ! inductive influ5ce ( ! prim>y1 al?\gh on op5 circuit x may exhibit "s electromotive =ce4 ,:5 ! /r5g? ( ! prim>y rea*es a c]ta9 value1 ! %ield ,c1 becom+ saturat$1 ceases to protect ! second>y f inductive action1 & curr5t is 9 consequ5ce develop$ !re94 ,= simil> reasons1 :5 ! prim>y curr5t weak5s1 ! weak5+ ( ! second>y is ret>d$ to ! same or approximately ! same ext5t4 ,illu/ration3 ,,fig4 #if4 ,! specific con/ruction ( ! trans=m] is l>gely immat]ial4 ,9 ,fig4 #if1 = example1 ! core ,a is built up ( ?9 insulat$ iron plates or discs4 ,! prim>y circuit ,d is w\nd next ! core ,a4 ,ov] ?is is appli$ ! %ield ,c1 :i* 9 ?is case is made up ( ?9 /rips or plates ( iron prop]ly insulat$ & surr\nd+ ! prim>y1 =m+ a clos$ magnetic circuit4 ,! second>y ,b is w\nd ov] ! %ield ,c4 ,9 ,fig4 #if1 also1 ,e is a s\rce ( alt]nat+ or rapidly *ang+ curr5ts4 ,! prim>y ( ! trans=m] is connect$ ) ! circuit ( ! g5]ator4 ,f is a two-circuit alt]nat+ curr5t motor1 "o ( ! circuits be+ connect$ ) ! ma9 circuit f ! s\rce ,e1 & ! o!r be+ suppli$ ) curr5ts f ! second>y ( ! trans=m]4 ,,"p ,,ii4 ,,! ,,tesla ,,effects ,,) ,,high ,,frequ5cy ,,& ,,high ,,pot5tial ,,curr5ts4 ,,*apt] ,,xxv4 ,,introduction4--,,! ,,scope ,,( ,,! ,,tesla ,,lectures4 ,be=e proce$+ to /udy ! ?ree ,tesla lectures "h pres5t$1 ! read] may f9d x ( "s assi/ance to h 8 att5tion direct$ to ! ma9 po9ts ( int]e/ & significance !re94 ,! fir/ ( ^! lectures 0 deliv]$ 9 ,new ,york1 at ,columbia ,college1 be=e ! ,am]ican ,in/itute ( ,electrical ,eng9e]s1 ,may #bj1 #ahia4 ,! urg5t desire express$ imm$iately f all p>ts ( ,europe = an opportunity to witness ! brilliant & unusual exp]im5ts ) :i* ! lecture 0 accompani$1 induc$ ,mr4 ,tesla to g to ,engl& e>ly 9 #ahib1 :5 he appe>$ be=e ! ,in/itution ( ,electrical ,eng9e]s1 & a day lat]1 by special reque/1 be=e ! ,royal ,in/itution4 ,8 reception 0 ( ! mo/ en?usia/ic & flatt]+ nature on bo? occasions4 ,he !n w5t1 by invitation1 to ,france1 & repeat$ 8 novel demon/rations be=e ! ,societe ,int]nationale des ,electrici5s1 & ! ,societe ,francaise de ,physique4 ,mr4 ,tesla return$ to ,am]ica 9 ! fall ( #ahib1 & 9 ,febru>y1 #ahic1 deliv]$ 8 ?ird lecture be=e ! ,frankl9 ,in/itute ( ,philadelphia1 9 fulfilm5t ( a long /&+ promise to ,pr(4 ,h\/on4 ,! foll[+ week1 at ! reque/ ( ,presid5t ,james ,i4 ,ay]1 ( ! ,national ,electric ,light ,association1 ! same lecture 0 re-deliv]$ 9 ,/4 ,l\is4 ,x _h be5 int5d$ to limit ! invitations to memb]s1 b ! appeals f resid5ts 9 ! city 7 s num]\s & press+ t x became necess>y to secure a v l>ge hall4 ,h5ce x came ab\t t ! lecture 0 li/5$ to by an audi5ce ( ov] #e1jjj p1 & 0 9 "s p>ts ( a m popul> nature ?an ei!r ( its pr$ecessors4 ,despite ?is concession to ! ne$ ( ! h\r & occasion1 ,mr4 ,tesla did n hesitate to %[ _m new & brilliant exp]im5ts1 & to advance ! fronti] ( discov]y f> beyond any po9t he _h !ret(ore m>k$ publicly4 ,we may n[ proce$ to a runn+ review ( ! lectures !mselves4 ,! gr\nd cov]$ by !m is s va/ t only ! lead+ ideas & exp]im5ts c "h be t\*$ ^u2 besides1 x is pref]able t ! lectures %\ld be c>efully gone ov] = _! own sake1 x be+ m ?an likely t ea* /ud5t w discov] a new beauty or /imulus 9 !m4 ,tak+ up ! c\rse ( reason+ foll[$ by ,mr4 ,tesla 9 8 fir/ lecture1 x w be not$ t he />t$ out ) ! recognition ( ! fact1 :i* he has n[ exp]im5tally demon/rat$1 t = ! production ( light waves1 prim>ily1 electro/atic effects mu/ be br\ght into play1 & cont9u$ /udy has l$ him to ! op9ion t all electrical & magnetic effects may be ref]r$ to electro/atic molecul> =ces4 ,?is op9ion f9ds a s+ul> confirmation 9 "o ( ! mo/ /rik+ exp]im5ts :i* he describes1 namely1 ! production ( a v]itable flame by ! agitation ( electro/atically *>g$ molecules4 ,x is ( ! highe/ int]e/ to obs]ve t ?is result po9ts out a way ( obta9+ a flame :i* consumes no mat]ial & 9 :i* no *emical action :atev] takes place4 ,x also ?r[s a light on ! nature ( ! ord9>y flame1 :i* ,mr4 ,tesla believes to be due to electro/atic molecul> actions1 :i*1 if true1 w\ld lead directly to ! idea t ev5 *emical aff9ities might be electro/atic 9 _! nature & t1 z has already be5 sugge/$1 molecul> =ces 9 g5]al may be ref]able to "o & ! same cause4 ,?is s+ul> ph5om5on acc\nts 9 a plausible mann] = ! unexpla9$ fact t build+s are frequ5tly set on fire dur+ ?und] /orms )\t hav+ be5 at all /ruck by lightn+4 ,x may also expla9 ! total disappe>ance ( %ips at sea4 ,"o ( ! /rik+ pro(s ( ! correctness ( ! ideas advanc$ by ,mr4 ,tesla is ! fact t1 not)/&+ ! employm5t ( ! mo/ p[]ful electromagnetic inductive effects1 b feeble lum9osity is obta9able1 & ?is only 9 close proximity to ! s\rce ( di/urbance2 :]eas1 :5 ! electro/atic effects are int5sifi$1 ! same initial en]gy suffices to excite lum9osity at consid]able di/ances f ! s\rce4 ,t !re are only electro/atic effects active seems to be cle>ly prov$ by ,mr4 ,tesla's exp]im5ts ) an induction coil op]at$ ) alt]nat+ curr5ts ( v high frequ5cy4 ,he %[s h[ tubes may be made to gl[ brilliantly at consid]able di/ances f any object :5 plac$ 9 a p[]ful1 rapidly alt]nat+1 electro/atic field1 & he describes _m int]e/+ ph5om5a obs]v$ 9 su* a field4 ,8 exp]im5ts op5 up ! possibility ( light+ an ap>tm5t by simply creat+ 9 x su* an electro/atic field1 & ?is1 9 a c]ta9 way1 w\ld appe> to be ! ideal me?od ( light+ a room1 z x w\ld all[ ! illum9at+ device to be freely mov$ ab\t4 ,! p[] ) :i* ^! exhau/$ tubes1 devoid ( any electrodes1 light up is c]ta9ly rem>kable4 ,t ! pr9ciple prop\nd$ by ,mr4 ,tesla is a broad "o is evid5t f ! _m ways 9 :i* x may be practically appli$4 ,we ne$ only ref] to ! v>iety ( ! devices %[n or describ$1 all ( :i* are novel 9 "* & w1 )\t d\bt1 lead to fur!r important results at ! h&s ( ,mr4 ,tesla & o!r inve/igators4 ,! exp]im5t1 = in/ance1 ( light+ up a s+le filam5t or block ( refractory mat]ial ) a s+le wire1 is 9 itself suffici5t to give ,mr4 ,tesla's "w ! /amp ( orig9ality1 & ! num]\s o!r exp]im5ts & effects :i* may be v>i$ at w1 are equally new & int]e/+4 ,?us1 ! inc&esc5t filam5t sp9n+ 9 an unexhau/$ globe1 ! well-kn[n ,crookes exp]im5t on op5 circuit1 & ! _m o!rs sugge/$1 w n fail to int]e/ ! read]4 ,mr4 ,tesla has made an exhau/ive /udy ( ! v>i\s =ms ( ! dis*>ge pres5t$ by an induction coil :5 op]at$ ) ^! rapidly alt]nat+ curr5ts1 />t+ f ! ?read-l dis*>ge & pass+ ?r\gh v>i\s /ages to ! true electric flame4 ,a po9t ( great importance 9 ! introduction ( high t5sion alt]nat+ curr5t :i* ,mr4 ,tesla br+s out is ! necessity ( c>efully avoid+ all gase\s matt] 9 ! high t5sion app>atus4 ,he %[s t1 at lea/ ) v rapidly alt]nat+ curr5ts ( high pot5tial1 ! dis*>ge may "w ?r\gh almo/ any practicable ?ickness ( ! be/ insulators1 if air is pres5t4 ,9 su* cases ! air includ$ )9 ! app>atus is viol5tly agitat$ & by molecul> bomb>dm5t ! p>ts may be s greatly heat$ z to cause a rupture ( ! insulation4 ,! practical outcome ( ?is is1 t1 :]eas ) /eady curr5ts1 any k9d ( insulation may be us$1 ) rapidly alt]nat+ curr5ts oils w probably be ! be/ to employ1 a fact :i* has be5 obs]v$1 b n until n[ satisfactorily expla9$4 ,! recognition ( ! above fact is ( special importance 9 ! con/ruction ( ! co/ly comm]cial induction coils :i* are (t5 r5d]$ useless 9 an unacc\ntable mann]4 ,! tru? ( ^! views ( ,mr4 ,tesla is made evid5t by ! int]e/+ exp]im5ts illu/rative ( ! behavior ( ! air betwe5 *>g$ surfaces1 ! lum9\s /reams =m$ by ! *>g$ molecules appe>+ ev5 :5 great ?icknesses ( ! be/ insulators are int]pos$ betwe5 ! *>g$ surfaces4 ,^! lum9\s /reams af=d 9 !mselves a v int]e/+ /udy = ! exp]im5t]4 ,) ^! rapidly alt]nat+ curr5ts !y become f> m p[]ful & produce beautiful light effects :5 !y issue f a wire1 p9:eel or o!r object atta*$ to a t]m9al ( ! coil2 & x is int]e/+ to note t !y issue f a ball almo/ z freely z f a po9t1 :5 ! frequ5cy is v high4 ,f ^! exp]im5ts we also obta9 a bett] idea ( ! importance ( tak+ into acc\nt ! capacity & self-induction 9 ! app>atus employ$ & ! possibilities (f]$ by ! use ( cond5s]s 9 conjunction ) alt]nate curr5ts1 ! employm5t ( curr5ts ( high frequ5cy1 among o!r ?+s1 mak+ x possible to r$uce ! cond5s] to practicable dim5sions4 ,ano!r po9t ( int]e/ & practical be>+ is ! fact1 prov$ by ,mr4 ,tesla1 t = alt]nate curr5ts1 especially ^? ( high frequ5cy1 insulators are requir$ possess+ a small specific inductive capacity1 :i* at ! same "t h a high insulat+ p[]4 ,mr4 ,tesla also makes int]e/+ & valuable sugge/ion 9 reg>d to ! economical utilization ( iron 9 ma*9es & trans=m]s4 ,he %[s h[1 by ma9ta9+ by cont9u\s magnetization a fl[ ( l9es ?r\gh ! iron1 ! latt] may be kept ne> its maximum p]meability & a high] output & economy may be secur$ 9 su* app>atus4 ,?is pr9ciple may prove ( consid]able comm]cial importance 9 ! developm5t ( alt]nat+ sy/ems4 ,mr4 ,tesla's sugge/ion t ! same result c be secur$ by heat+ ! iron by hy/]esis & eddy curr5ts1 & increas+ ! p]meability 9 ?is mann]1 :ile x may appe> less practical1 nev]!less op5s ano!r direction = inve/igation & improvem5t4 ,! demon/ration ( ! fact t ) alt]nat+ curr5ts ( high frequ5cy1 suffici5t en]gy may be transmitt$ "u practicable conditions ?r\gh ! glass ( an inc&esc5t lamp by electro/atic or electromagnetic induction may lead to a dep>ture 9 ! con/ruction ( su* devices4 ,ano!r important exp]im5tal result a*iev$ is ! op]ation ( lamps1 & ev5 motors1 ) ! dis*>ges ( cond5s]s1 ?is me?od af=d+ a means ( conv]t+ direct or alt]nat+ curr5ts4 ,9 ?is connection ,mr4 ,tesla advocates ! p]fect+ ( app>atus capable ( g5]at+ electricity ( high t5sion f heat en]gy1 believ+ ?is to be a bett] way ( obta9+ electrical en]gy = practical purposes1 p>ticul>ly = ! production ( light4 ,:ile _m 7 probably prep>$ to enc\nt] curi\s ph5om5a ( imp$ance 9 ! use ( a cond5s] dis*>g$ disruptively1 ! exp]im5ts %[n 7 extremely int]e/+ on acc\nt ( _! p>adoxical "*4 ,! burn+ ( an inc&esc5t lamp at any c&le p[] :5 connect$ across a heavy metal b>1 ! exi/5ce ( nodes on ! b> & ! possibility ( explor+ ! b> by means ( an ord9>y ,c>dew voltmet]1 are all peculi> developm5ts1 b p]haps ! mo/ int]e/+ obs]vation is ! ph5om5on ( imp$ance obs]v$ 9 ! lamp ) a /raight filam5t1 :i* rema9s d>k :ile ! bulb gl[s4 ,mr4 ,tesla's mann] ( op]at+ an induction coil by means ( ! disruptive dis*>ge1 & ?us obta9+ enorm\s diff]5ces ( pot5tial f comp>atively small & inexp5sive coils1 w be appreciat$ by exp]im5t]s & w f9d valuable application 9 laboratories4 ,inde$1 8 _m sugge/ions & h9ts 9 reg>d to ! con/ruction & use ( app>atus 9 ^! inve/igations w be highly valu$ & w aid mat]ially 9 future rese>*4 ,! ,london lecture 0 deliv]$ twice4 ,9 its fir/ =m1 be=e ! ,in/itution ( ,electrical ,eng9e]s1 x 0 9 "s respects an amplification ( sev]al po9ts n specially enl>g$ ^u 9 ! ,new ,york lecture1 b br\ght =w>d _m additional discov]ies & new inve/igations4 ,its repetition1 9 ano!r =m1 at ! ,royal ,in/itution1 0 due to ,pr(4 ,dew>1 :o ) ,"l ,rayleigh1 manife/$ a mo/ lively int]e/ 9 ,mr4 ,tesla's "w1 & ^: k9dness illu/rat$ once m ! /rong ,engli% love ( sci5tific tru? & appreciation ( its vot>ies4 ,z an indefatigable exp]im5t]1 ,mr4 ,tesla 0 c]ta9ly n[h]e m at home ?an 9 ! haunts ( ,f>aday1 & z ! gue/ ( ,f>aday's successor4 ,?is ,royal ,in/itution lecture summ$ up ! lead+ po9ts ( ,mr4 ,tesla's "w1 9 ! high pot5tial1 high frequ5cy field1 & we may "h avail ourselves ( s valuable a summ>ization1 9 a simple =m1 ( a subject by no means easy ( compreh5sion until x has be5 ?or\ghly /udi$4 ,9 ^! ,london lectures1 among ! _m notable po9ts made 0 fir/1 ! difficulty ( con/ruct+ ! alt]nators to obta9 ! v high frequ5cies ne$$4 ,to obta9 ! high frequ5cies x 0 necess>y to provide sev]al hundr$ pol> projections1 :i* 7 necess>ily small & (f]$ _m drawbacks1 & ?is ! m z exce$+ly high p]iph]al spe$s _h to be resort$ to4 ,9 "s ( ! fir/ ma*9es bo? armature & field _h pol> projections4 ,^! ma*9es produc$ a curi\s noise1 especially :5 ! armature 0 />t$ f ! /ate ( re/1 ! field be+ *>g$4 ,! mo/ effici5t ma*9e 0 f\nd to be "o ) a drum armature1 ! iron body ( :i* consi/$ ( v ?9 wire anneal$ ) special c>e4 ,x 01 ( c\rse1 desirable to avoid ! employm5t ( iron 9 ! armature1 & sev]al ma*9es ( ?is k9d1 ) mov+ or /ation>y conductors 7 con/ruct$1 b ! results obta9$ 7 n q satisfactory1 on acc\nt ( ! great me*anical & o!r difficulties enc\nt]$4 ,! /udy ( ! prop]ties ( ! high frequ5cy curr5ts obta9$ f ^! ma*9es is v int]e/+1 z ne>ly e exp]im5t discloses some?+ new4 ,two coils trav]s$ by su* a curr5t attract or repel ea* o!r ) a =ce :i*1 ow+ to ! imp]fection ( our s5se ( t\*1 seems cont9u\s4 ,an int]e/+ obs]vation1 already not$ "u ano!r =m1 is t a piece ( iron1 surr\nd$ by a coil ?r\gh :i* ! curr5t is pass+ appe>s to be cont9u\sly magnetiz$4 ,?is app>5t cont9uity might be ascrib$ to ! defici5cy ( ! s5se ( t\*1 b !re is evid5ce t 9 curr5ts ( su* high frequ5cies "o ( ! impulses prepond]ates ov] ! o!r4 ,z might be expect$1 conductors trav]s$ by su* curr5ts are rapidly heat$1 ow+ to ! increase ( ! resi/ance1 & ! heat+ effects are relatively mu* great] 9 ! iron4 ,! hy/]esis losses 9 iron are s great t an iron core1 ev5 if f9ely subdivid$1 is heat$ 9 an incr$ibly %ort "t4 ,to give an idea ( ?is1 an ord9>y iron wire #a_/af in* 9 diamet] ins]t$ )9 a coil hav+ #bej turns1 ) a curr5t e/imat$ to be five amp]es pass+ ?r\gh ! coil1 becomes )9 two seconds' "t s hot z to scor* wood4 ,beyond a c]ta9 frequ5cy1 an iron core1 no matt] h[ f9ely subdivid$1 ex]cises a damp5+ effect1 & x 0 easy to f9d a po9t at :i* ! imp$ance ( a coil 0 n affect$ by ! pres5ce ( a core consi/+ ( a bundle ( v ?9 well anneal$ & v>ni%$ iron wires4 ,exp]im5ts ) a telephone1 a conductor 9 a /rong magnetic field1 or ) a cond5s] or arc1 seem to af=d c]ta9 pro( t s\nds f> above ! usually accept$ limit ( he>+ w\ld be p]ceiv$ if produc$ ) suffici5t p[]4 ,! arc produc$ by ^! curr5ts possesses sev]al int]e/+ features4 ,usually x emits a note ! pit* ( :i* corresponds to twice ! frequ5cy ( ! curr5t1 b if ! frequ5cy be suffici5tly high x becomes noiseless1 ! limit ( audition be+ det]m9$ pr9cipally by ! l9e> dim5sions ( ! arc4 ,a curi\s feature ( ! arc is its p]si/5cy1 :i* is due p>tly to ! inability ( ! gase\s column to cool & increase consid]ably 9 resi/ance1 z is ! case ) l[ frequ5cies1 & p>tly to ! t5d5cy ( su* a high frequ5cy ma*9e to ma9ta9 a con/ant curr5t4 ,9 connection ) ^! ma*9es ! cond5s] af=ds a p>ticul>ly int]e/+ /udy4 ,/rik+ effects are produc$ by prop] adju/m5ts ( capacity & self-induction4 ,x is easy to raise ! electromotive =ce ( ! ma*9e to _m times ! orig9al value by simply adju/+ ! capacity ( a cond5s] connect$ 9 ! induc$ circuit4 ,if ! cond5s] be at "s di/ance f ! ma*9e1 ! diff]5ce ( pot5tial on ! t]m9als ( ! latt] may be only a small fraction ( t on ! cond5s]4 ,b ! mo/ int]e/+ exp]i5ces are ga9$ :5 ! t5sion ( ! curr5ts f ! ma*9e is rais$ by means ( an induction coil4 ,9 consequ5ce ( ! enorm\s rate ( *ange obta9able 9 ! prim>y curr5t1 mu* high] pot5tial diff]5ces are obta9$ ?an ) coils op]at$ 9 ! usual ways1 &1 ow+ to ! high frequ5cy1 ! second>y dis*>ge possesses _m /rik+ peculi>ities4 ,bo? ! electrodes behave g5]ally alike1 ?\gh x appe>s f "s obs]vations t "o curr5t impulse prepond]ates ov] ! o!r1 z be=e m5tion$4 ,! physiological effects ( ! high t5sion dis*>ge are f\nd to be s small t ! %ock ( ! coil c be support$ )\t any inconv5i5ce1 except p]haps a small burn produc$ by ! dis*>ge ^u approa*+ ! h& to "o ( ! t]m9als4 ,! decid$ly small] physiological effects ( ^! curr5ts are ?\ght to be due ei!r to a diff]5t di/ribution ?r\gh ! body or to ! tissues act+ z cond5s]s4 ,b 9 ! case ( an induction coil ) a great _m turns ! h>mlessness is pr9cipally due to ! fact t b little en]gy is available 9 ! ext]nal circuit :5 ! same is clos$ ?r\gh ! exp]im5t]'s body1 on acc\nt ( ! great imp$ance ( ! coil4 ,9 v>y+ ! frequ5cy & /r5g? ( ! curr5ts ?r\gh ! prim>y ( ! coil1 ! "* ( ! second>y dis*>ge is greatly v>i$1 & no less ?an five di/9ct =ms are obs]v$3--,a weak1 s5sitive ?read dis*>ge1 a p[]ful flam+ dis*>ge1 & ?ree =ms ( bru% or /ream+ dis*>ges4 ,ea* ( ^! possesses c]ta9 notewor?y features1 b ! mo/ int]e/+ to /udy are ! latt]4 ,"u c]ta9 conditions ! /reams1 :i* are presumably due to ! viol5t agitation ( ! air molecules1 issue freely f all po9ts ( ! coil1 ev5 ?r\gh a ?ick insulation4 ,if !re is ! smalle/ air space betwe5 ! prim>y & second>y1 !y w =m !re & surely injure ! coil by sl[ly w>m+ ! insulation4 ,z !y =m ev5 ) ord9>y frequ5cies :5 ! pot5tial is excessive1 ! air-space mu/ be mo/ c>efully avoid$4 ,^! high frequ5cy /ream]s diff] 9 aspect & prop]ties f ^? produc$ by a /atic ma*9e4 ,! w9d produc$ by !m is small & %\ld altoge!r cease if /ill consid]ably high] frequ5cies c\ld be obta9$4 ,a peculi>ity is t !y issue z freely f surfaces z f po9ts4 ,ow+ to ?is1 a metallic vane1 m\nt$ 9 "o ( ! t]m9als ( ! coil s z to rotate freely1 & hav+ "o ( its sides cov]$ ) insulation1 is spun rapidly ar\nd4 ,su* a vane w\ld n rotate ) a /eady pot5tial1 b ) a high frequ5cy coil x w sp91 ev5 if x be entirely cov]$ ) insulation1 provid$ ! insulation on "o side be ei!r ?ick] or ( a high] specific inductive capacity4 ,a ,crookes electric radiomet] is also spun ar\nd :5 connect$ to "o ( ! t]m9als ( ! coil1 b only at v high exhau/ion or at ord9>y pressures4 ,!re is /ill ano!r & m /rik+ peculi>ity ( su* a high frequ5cy /ream]1 namely1 x is hot4 ,! heat is easily p]ceptible ) frequ5cies ( ab\t #aj1jjj1 ev5 if ! pot5tial is n excessively high4 ,! heat+ effect is1 ( c\rse1 due to ! molecul> impacts & collisions4 ,c\ld ! frequ5cy & pot5tial be pu%$ f> en\gh1 !n a bru% c\ld be produc$ resembl+ 9 e p>ticul> a flame & giv+ light & heat1 yet )\t a *emical process tak+ place4 ,! hot bru%1 :5 prop]ly produc$1 resembles a jet ( burn+ gas escap+ "u great pressure1 & x emits an extraord9>y /rong smell ( ozone4 ,! great ozoniz+ action is ascrib$ to ! fact t ! agitation ( ! molecules ( ! air is m viol5t 9 su* a bru% ?an 9 ! ord9>y /ream] ( a /atic ma*9e4 ,b ! mo/ p[]ful bru% dis*>ges 7 produc$ by employ+ curr5ts ( mu* high] frequ5cies ?an x 0 possible to obta9 by means ( ! alt]nators4 ,^! curr5ts 7 obta9$ by disruptively dis*>g+ a cond5s] & sett+ up oscillations4 ,9 ?is mann] curr5ts ( a frequ5cy ( sev]al hundr$ ?\s& 7 obta9$4 ,curr5ts ( ?is k9d1 ,mr4 ,tesla po9t$ out1 produce /rik+ effects4 ,at ^! frequ5cies1 ! imp$ance ( a copp] b> is s great t a pot5tial diff]5ce ( sev]al hundr$ volts c be ma9ta9$ betwe5 two po9ts ( a %ort & ?ick b>1 & x is possible to keep an ord9>y inc&esc5t lamp burn+ at full c&le p[] by atta*+ ! t]m9als ( ! lamp to two po9ts ( ! b> no m ?an a few in*es ap>t4 ,:5 ! frequ5cy is extremely high1 nodes are f\nd to exi/ on su* a b>1 & x is easy to locate !m by means ( a lamp4 ,by conv]t+ ! high t5sion dis*>ges ( a l[ frequ5cy coil 9 ?is mann]1 x 0 f\nd practicable to keep a few lamps burn+ on ! ord9>y circuit 9 ! laboratory1 & by br++ ! undulation to a l[ pit*1 x 0 possible to op]ate small motors4 ,?is plan likewise all[s ( conv]t+ high t5sion dis*>ges ( "o direction into l[ t5sion unidirectional curr5ts1 by adju/+ ! circuit s t !re are no oscillations4 ,9 pass+ ! oscillat+ dis*>ges ?r\gh ! prim>y ( a specially con/ruct$ coil1 x is easy to obta9 enorm\s pot5tial diff]5ces ) only few turns ( ! second>y4 ,great difficulties 7 at fir/ exp]i5c$ 9 produc+ a successful coil on ?is plan4 ,x 0 f\nd necess>y to keep all air1 or gase\s matt] 9 g5]al1 away f ! *>g$ surfaces1 & oil imm]sion 0 resort$ to4 ,! wires us$ 7 heavily cov]$ ) gutta-p]*a & w\nd 9 oil1 or ! air 0 pump$ out by means ( a ,spr5gel pump4 ,! g5]al arrangem5t 0 ! foll[+3--,an ord9>y induction coil1 op]at$ f a l[ frequ5cy alt]nator1 0 us$ to *>ge ,leyd5 j>s4 ,! j>s 7 made to dis*>ge ov] a s+le or multiple gap ?r\gh ! prim>y ( ! second coil4 ,to insure ! action ( ! gap1 ! arc 0 bl[n out by a magnet or air bla/4 ,to adju/ ! pot5tial 9 ! second>y a small oil cond5s] 0 us$1 or poli%$ brass sph]es ( diff]5t sizes 7 screw$ on ! t]m9als & _! di/ance adju/$4 ,:5 ! conditions 7 c>efully det]m9$ to suit ea* exp]im5t1 magnific5t effects 7 obta9$4 ,two wires1 /ret*$ ?r\gh ! room1 ea* be+ connect$ to "o ( ! t]m9als ( ! coil1 emitt$ /reams s p[]ful t ! light f !m all[$ di/+ui%+ ! objects 9 ! room2 ! wires became lum9\s ev5 ?\gh cov]$ ) ?ick & mo/ excell5t insulation4 ,:5 two /raight wires1 or two conc5tric circles ( wire1 are connect$ to ! t]m9als1 & set at ! prop] di/ance1 a uni=m lum9\s %eet is produc$ betwe5 !m4 ,x 0 possible 9 ?is way to cov] an area ( m ?an "o met] squ>e completely ) ! /reams4 ,by atta*+ to "o t]m9al a l>ge circle ( wire & to ! o!r t]m9al a small sph]e1 ! /reams are focus$ ^u ! sph]e1 produce a /rongly light$ spot ^u ! same1 & pres5t ! appe>ance ( a lum9\s cone4 ,a v ?9 wire glu$ ^u a plate ( h>d rubb] ( great ?ickness1 on ! opposite side ( :i* is fa/5$ a t9foil coat+1 is r5d]$ int5sely lum9\s :5 ! coat+ is connect$ to ! o!r t]m9al ( ! coil4 ,su* an exp]im5t c be p]=m$ also ) l[ frequ5cy curr5ts1 b mu* less satisfactorily4 ,:5 ! t]m9als ( su* a coil1 ev5 ( a v small "o1 are sep>at$ by a rubb] or glass plate1 ! dis*>ge spreads ov] ! plate 9 ! =m ( /reams1 ?reads or brilliant sp>ks1 & af=ds a magnific5t display1 :i* _c be equal$ by ! l>ge/ coil op]at$ 9 ! usual ways4 ,by a simple adju/m5t x is possible to produce ) ! coil a succession ( brilliant sp>ks1 exactly z ) a ,holtz ma*9e4 ,"u c]ta9 conditions1 :5 ! frequ5cy ( ! oscillation is v great1 :ite1 phantom-l /reams are se5 to break =? f ! t]m9als ( ! coil4 ,! *ief int]e/+ feature ab\t !m is1 t !y /ream freely aga9/ ! out/ret*$ h& or o!r conduct+ object )\t produc+ any s5sation1 & ! h& may be approa*$ v ne> to ! t]m9al )\t a sp>k be+ induc$ to jump4 ,?is is due presumably to ! fact t a consid]able portion ( ! en]gy is c>ri$ away or dissipat$ 9 ! /ream]s1 & ! diff]5ce ( pot5tial betwe5 ! t]m9al & ! h& is dim9i%$4 ,x is f\nd 9 su* exp]im5ts t ! frequ5cy ( ! vibration & ! quickness ( succession ( ! sp>ks betwe5 ! knobs affect to a m>k$ degree ! appe>ance ( ! /reams4 ,:5 ! frequ5cy is v l[1 ! air gives way 9 m or less ! same mann] z by a /eady diff]5ce ( pot5tial1 & ! /reams consi/ ( di/9ct ?reads1 g5]ally m+l$ ) ?9 sp>ks1 :i* probably correspond to ! successive dis*>ges occurr+ betwe5 ! knobs4 ,b :5 ! frequ5cy is v high1 & ! arc ( ! dis*>ge produces a s\nd :i* is l\d & smoo? 7:i* indicates bo? t oscillation takes place & t ! sp>ks succe$ ea* o!r ) great rapidity71 !n ! lum9\s /reams =m$ are p]fectly uni=m4 ,!y are g5]ally ( a purpli% hue1 b :5 ! molecul> vibration is increas$ by rais+ ! pot5tial1 !y assume a :ite color4 ,! lum9\s int5sity ( ! /reams increases rapidly :5 ! pot5tial is increas$2 & ) frequ5cies ( only a few hundr$ ?\s&1 c\ld ! coil be made to )/& a suffici5tly high pot5tial diff]5ce1 !re is no d\bt t ! space ar\nd a wire c\ld be made to emit a /rong light1 m]ely by ! agitation ( ! molecules ( ! air at ord9>y pressure4 ,su* dis*>ges ( v high frequ5cy :i* r5d] lum9\s ! air at ord9>y pressure we h v likely occasion to witness 9 ! aurora borealis4 ,f _m ( ^! exp]im5ts x seems reasonable to inf] t sudd5 cosmic di/urbances1 su* z eruptions on ! sun1 set ! electro/atic *>ge ( ! e>? 9 an extremely rapid vibration1 & produce ! gl[ by ! viol5t agitation ( ! air 9 ! upp] & ev5 9 ! l[] /rata4 ,x is ?\ght t if ! frequ5cy 7 l[1 or ev5 m s if ! *>ge 7 n at all vibrat+1 ! l[] d5se /rata w\ld break d[n z 9 a lightn+ dis*>ge4 ,indications ( su* break+ d[n h be5 repeat$ly obs]v$1 b !y c be attribut$ to ! fundam5tal di/urbances1 :i* are few 9 numb]1 = ! sup]impos$ vibration w\ld be s rapid z n to all[ a disruptive break4 ,! /udy ( ^! dis*>ge ph5om5a has l$ ,mr4 ,tesla to ! recognition ( "s important facts4 ,x 0 f\nd1 z already /at$1 t gase\s matt] mu/ be mo/ c>efully exclud$ f any dielectric :i* is subject$ to great1 rapidly *ang+ electro/atic /resses4 ,s9ce x is difficult to exclude ! gas p]fectly :5 solid insulators are us$1 x is necess>y to resort to liquid dielectrics4 ,:5 a solid dielectric is us$1 x matt]s little h[ ?ick & h[ good x is2 if air be pres5t1 /ream]s =m1 :i* gradually heat ! dielectric & impair its insulat+ p[]1 & ! dis*>ge f9ally breaks ?r\gh4 ,"u ord9>y conditions ! be/ insulators are ^? :i* possess ! highe/ specific inductive capacity1 b su* insulators are n ! be/ to employ :5 work+ ) ^! high frequ5cy curr5ts1 = 9 mo/ cases ! high] specific inductive capacity is r a disadvantage4 ,! prime quality ( ! insulat+ m$ium = ^! curr5ts is cont9uity4 ,= ?is reason pr9cipally x is necess>y to employ liquid insulators1 su* z oils4 ,if two metal plates1 connect$ to ! t]m9als ( ! coil1 are imm]s$ 9 oil & set a di/ance ap>t1 ! coil may be kept work+ = any l5g? ( "t )\t a break occurr+1 or )\t ! oil be+ w>m$1 b if air bubbles are introduc$1 !y become lum9\s2 ! air molecules1 by _! impact aga9/ ! oil1 heat x1 & aft] "s "t cause ! insulation to give way4 ,if1 in/ead ( ! oil1 a solid plate ( ! be/ dielectric1 ev5 sev]al times ?ick] ?an ! oil int]v5+ betwe5 ! metal plates1 is ins]t$ betwe5 ! latt]1 ! air hav+ free access to ! *>g$ surfaces1 ! dielectric inv>iably is w>m$ & breaks d[n4 ,! employm5t ( oil is advisable or necess>y ev5 ) l[ frequ5cies1 if ! pot5tials are su* t /ream]s =m1 b only 9 su* cases1 z is evid5t f ! !ory ( ! action4 ,if ! pot5tials are s l[ t /ream]s d n =m1 !n x is ev5 disadvantage\s to employ oil1 = x may1 pr9cipally by conf9+ ! heat1 be ! cause ( ! break+ d[n ( ! insulation4 ,! exclusion ( gase\s matt] is n only desirable on acc\nt ( ! safety ( ! app>atus1 b also on acc\nt ( economy1 especially 9 a cond5s]1 9 :i* consid]able wa/e ( p[] may occur m]ely ow+ to ! pres5ce ( air1 if ! electric d5sity on ! *>g$ surfaces is great4 ,9 ! c\rse ( ^! inve/igations a ph5om5on ( special sci5tific int]e/ 0 obs]v$4 ,x may be rank$ among ! bru% ph5om5a1 9 fact x is a k9d ( bru% :i* =ms at1 or ne>1 a s+le t]m9al 9 high vacuum4 ,9 a bulb ) a conduct+ electrode1 ev5 if ! latt] be ( alum9um1 ! bru% has only a v %ort exi/5ce1 b x c be pres]v$ = a consid]able l5g? ( "t 9 a bulb devoid ( any conduct+ electrode4 ,to obs]ve ! ph5om5on x is f\nd be/ to employ a l>ge sph]ical bulb hav+ 9 its c5tre a small bulb support$ on a tube seal$ to ! neck ( ! =m]4 ,! l>ge bulb be+ exhau/$ to a high degree1 & ! inside ( ! small bulb be+ connect$ to "o ( ! t]m9als ( ! coil1 "u c]ta9 conditions !re appe>s a mi/y haze ar\nd ! small bulb1 :i*1 aft] pass+ ?r\gh "s /ages1 assumes ! =m ( a bru%1 g5]ally at "r angles to ! tube support+ ! small bulb4 ,:5 ! bru% assumes ?is =m x may be br\ght to a /ate ( extreme s5sitiv5ess to electro/atic & magnetic influ5ce4 ,! bulb hang+ /raight d[n1 & all objects be+ remote f x1 ! approa* ( ! obs]v] )9 a few paces w cause ! bru% to fly to ! opposite side1 & if he walks ar\nd ! bulb x w always keep on ! opposite side4 ,x may beg9 to sp9 ar\nd ! t]m9al long be=e x rea*es t s5sitive /age4 ,:5 x beg9s to turn ar\nd1 pr9cipally1 b also be=e1 x is affect$ by a magnet1 & at a c]ta9 /age x is susceptible to magnetic influ5ce to an a/oni%+ degree4 ,a small p]man5t magnet1 ) its poles at a di/ance ( no m ?an two c5timetres w affect x visibly at a di/ance ( two metres1 sl[+ d[n or accel]at+ ! rotation accord+ to h[ x is held relatively to ! bru%4 ,:5 ! bulb hangs ) ! globe d[n1 ! rotation is always clockwise4 ,9 ! s\!rn hemisph]e x w\ld occur 9 ! opposite direction1 & on ! 7magnetic7 equator ! bru% %\ld n turn at all4 ,! rotation may be rev]s$ by a magnet kept at "s di/ance4 ,! bru% rotates be/1 seem+ly1 :5 x is at "r angles to ! l9es ( =ce ( ! e>?4 ,x v likely rotates1 :5 at its maximum spe$1 9 syn*ronism ) ! alt]nations1 say1 #aj1jjj times a second4 ,! rotation c be sl[$ d[n or accel]at$ by ! approa* or recession ( ! obs]v]1 or any conduct+ body1 b x _c be rev]s$ by putt+ ! bulb 9 any position4 ,v curi\s exp]im5ts may be p]=m$ ) ! bru% :5 9 its mo/ s5sitive /ate4 ,= in/ance1 ! bru% re/+ 9 "o position1 ! exp]im5t] may1 by select+ a prop] position1 approa* ! h& at a c]ta9 consid]able di/ance to ! bulb1 & he may cause ! bru% to pass (f by m]ely /iff5+ ! muscles ( ! arm1 ! m]e *ange ( configuration ( ! arm & ! consequ5t imp]ceptible displacem5t be+ suffici5t to di/urb ! delicate balance4 ,:5 x beg9s to rotate sl[ly1 & ! h&s are held at a prop] di/ance1 x is impossible to make ev5 ! slighte/ motion )\t produc+ a visible effect ^u ! bru%4 ,a metal plate connect$ to ! o!r t]m9al ( ! coil affects x at a great di/ance1 sl[+ d[n ! rotation (t5 to "o turn a second4 ,mr4 ,tesla hopes t ?is ph5om5on w prove a valuable aid 9 ! inve/igation ( ! nature ( ! =ces act+ 9 an electro/atic or magnetic field4 ,if !re is any motion :i* is measurable go+ on 9 ! space1 su* a bru% w\ld be apt to reveal x4 ,x is1 s to speak1 a beam ( light1 frictionless1 devoid ( in]tia4 ,on acc\nt ( its m>vell\s s5sitiv5ess to electro/atic or magnetic di/urbances x may be ! means ( s5d+ signals ?r\gh subm>9e cables ) any spe$1 & ev5 ( transmitt+ intellig5ce to a di/ance )\t wires4 ,9 op]at+ an induction coil ) ^! rapidly alt]nat+ curr5ts1 x is a/oni%+ to note1 = ! fir/ "t1 ! great importance ( ! relation ( capacity1 self-induction1 & frequ5cy z be>+ ^u ! g5]al result4 ,! comb9$ effect ( ^! elem5ts produces _m curi\s effects4 ,= in/ance1 two metal plates are connect$ to ! t]m9als & set at a small di/ance1 s t an arc is =m$ betwe5 !m4 ,?is arc prev5ts a /rong curr5t f fl[+ ?r\gh ! coil4 ,if ! arc be int]rupt$ by ! int]position ( a glass plate1 ! capacity ( ! cond5s] obta9$ c\nt]acts ! self-induction1 & a /rong] curr5t is made to pass4 ,! effects ( capacity are ! mo/ /rik+1 = 9 ^! exp]im5ts1 s9ce ! self-induction & frequ5cy bo? are high1 ! critical capacity is v small1 & ne$ be b slightly v>i$ to produce a v consid]able *ange4 ,! exp]im5t] br+s 8 body 9 contact ) ! t]m9als ( ! second>y ( ! coil1 or atta*es to "o or bo? t]m9als insulat$ bodies ( v small bulk1 su* z exhau/$ bulbs1 & he produces a consid]able rise or fall ( pot5tial on ! second>y1 & greatly affects ! fl[ ( ! curr5t ?r\gh ! prim>y coil4 ,9 _m ( ! ph5om5a obs]v$1 ! pres5ce ( ! air1 or1 g5]ally speak+1 ( a m$ium ( a gase\s nature 7us+ ?is t]m n to imply specific prop]ties1 b 9 contradi/9ction to homog5eity or p]fect cont9uity7 plays an important "p1 z x all[s en]gy to be dissipat$ by molecul> impact or bomb>dm5t4 ,! action is ?us expla9$3--,:5 an insulat$ body connect$ to a t]m9al ( ! coil is sudd5ly *>g$ to high pot5tial1 x acts inductively ^u ! surr\nd+ air1 or :atev] gase\s m$ium !re might be4 ,! molecules or atoms :i* are ne> x are1 ( c\rse1 m attract$1 & move ?r\gh a great] di/ance ?an ! fur!r ones4 ,:5 ! ne>e/ molecules /rike ! body !y are repell$1 & collisions occur at all di/ances )9 ! inductive di/ance4 ,x is n[ cle> t1 if ! pot5tial be /eady1 b little loss ( en]gy c be caus$ 9 ?is way1 = ! molecules :i* are ne>e/ to ! body hav+ _h an additional *>ge imp>t$ to !m by contact1 are n attract$ until !y h p>t$1 if n ) all1 at lea/ ) mo/ ( ! additional *>ge1 :i* c be accompli%$ only aft] a great _m collisions4 ,?is is inf]r$ f ! fact t ) a /eady pot5tial !re is b little loss 9 dry air4 ,:5 ! pot5tial1 in/ead ( be+ /eady1 is alt]nat+1 ! conditions are entirely diff]5t4 ,9 ?is case a rhy?mical bomb>dm5t occurs1 no matt] :e!r ! molecules aft] com+ 9 contact ) ! body lose ! imp>t$ *>ge or n1 &1 :at is m1 if ! *>ge is n lo/1 ! impacts are all ! m viol5t4 ,/ill1 if ! frequ5cy ( ! impulses be v small1 ! loss caus$ by ! impacts & collisions w\ld n be s]i\s unless ! pot5tial 0 excessive4 ,b :5 extremely high frequ5cies & m or less high pot5tials are us$1 ! loss may be v great4 ,! total en]gy lo/ p] unit ( "t is proportionate to ! product ( ! numb] ( impacts p] second1 or ! frequ5cy & ! en]gy lo/ 9 ea* impact4 ,b ! en]gy ( an impact mu/ be proportionate to ! squ>e ( ! electric d5sity ( ! body1 on ! assumption t ! *>ge imp>t$ to ! molecule is proportionate to t d5sity4 ,x is conclud$ f ?is t ! total en]gy lo/ mu/ be proportionate to ! product ( ! frequ5cy & ! squ>e ( ! electric d5sity2 b ?is law ne$s exp]im5tal confirmation4 ,assum+ ! prec$+ consid]ations to be true1 !n1 by rapidly alt]nat+ ! pot5tial ( a body imm]s$ 9 an insulat+ gase\s m$ium1 any am\nt ( en]gy may be dissipat$ into space4 ,mo/ ( t en]gy1 !n1 is n dissipat$ 9 ! =m ( long e!r waves1 propagat$ to consid]able di/ance1 z is ?\ght mo/ g5]ally1 b is consum$ 9 impact & collisional losses--t is1 heat vibrations--on ! surface & 9 ! vic9ity ( ! body4 ,to r$uce ! dissipation x is necess>y to "w ) a small electric d5sity--! small]1 ! high] ! frequ5cy4 ,! behavior ( a gase\s m$ium to su* rapid alt]nations ( pot5tial makes x appe> plausible t electro/atic di/urbances ( ! e>?1 produc$ by cosmic ev5ts1 may h great influ5ce ^u ! meteorological conditions4 ,:5 su* di/urbances occur bo? ! frequ5cy ( ! vibrations ( ! *>ge & ! pot5tial are 9 all probability excessive1 & ! en]gy conv]t$ into heat may be consid]able4 ,s9ce ! d5sity mu/ be unev5ly di/ribut$1 ei!r 9 consequ5ce ( ! irregul>ity ( ! e>?'s surface1 or on acc\nt ( ! condition ( ! atmosph]e 9 v>i\s places1 ! effect produc$ w\ld accord+ly v>y f place to place4 ,consid]able v>iations 9 ! temp]ature & pressure ( ! atmosph]e may 9 ?is mann] be caus$ at any po9t ( ! surface ( ! e>?4 ,! v>iations may be gradual or v sudd51 accord+ to ! nature ( ! orig9al di/urbance1 & may produce ra9 & /orms1 or locally modify ! wea!r 9 any way4 ,f _m exp]i5ces ga!r$ 9 ! c\rse ( ^! inve/igations x appe>s c]ta9 t 9 lightn+ dis*>ges ! air is an elem5t ( importance4 ,= in/ance1 dur+ a /orm a /ream may =m on a nail or po9t$ projection ( a build+4 ,if lightn+ /rikes some:]e 9 ! neighborhood1 ! h>mless /atic dis*>ge may1 9 consequ5ce ( ! oscillations set up1 assume ! "* ( a high-frequ5cy /ream]1 & ! nail or projection may be br\ght to a high temp]ature by ! viol5t impact ( ! air molecules4 ,?us1 x is ?\ght1 a build+ may be set on fire )\t ! lightn+ /rik+ x4 ,9 l mann] small metallic objects may be fus$ & volatiliz$--z frequ5tly occurs 9 lightn+ dis*>ges--m]ely because !y are surr\nd$ by air4 ,7 !y imm]s$ 9 a practically cont9u\s m$ium1 su* z oil1 !y w\ld probably be safe1 z ! en]gy w\ld h to sp5d itself else:]e4 ,an in/ructive exp]i5ce hav+ a be>+ on ?is subject is ! foll[+3--,a glass tube ( an in* or s 9 diamet] & sev]al in*es long is tak51 & a plat9um wire seal$ into x1 ! wire runn+ ?r\gh ! c5t] ( ! tube f end to end4 ,! tube is exhau/$ to a mod]ate degree4 ,if a /eady curr5t is pass$ ?r\gh ! wire x is heat$ uni=mly 9 all p>ts & ! gas 9 ! tube is ( no consequ5ce4 ,b if high frequ5cy dis*>ges are direct$ ?r\gh ! wire1 x is heat$ m on ! ends ?an 9 ! middle portion1 & if ! frequ5cy1 or rate ( *>ge1 is high en\gh1 ! wire might z well be cut 9 ! middle z n1 = mo/ ( ! heat+ on ! ends is due to ! r>efi$ gas4 ,"h ! gas might only act z a conductor ( no imp$ance1 div]t+ ! curr5t f ! wire z ! imp$ance ( ! latt] is enorm\sly increas$1 & m]ely heat+ ! ends ( ! wire by reason ( _! resi/ance to ! passage ( ! dis*>ge4 ,b x is n at all necess>y t ! gas 9 ! tube %\ld be conduct+2 x might be at an extremely l[ pressure1 /ill ! ends ( ! wire w\ld be heat$2 h[ev]1 z is asc]ta9$ by exp]i5ce1 only ! two ends w\ld 9 su* case n be electrically connect$ ?r\gh ! gase\s m$ium4 ,n[1 :at ) ^! frequ5cies & pot5tials occurs 9 an exhau/$ tube1 occurs 9 ! lightn+ dis*>ge at ord9>y pressure4 ,f ! facility ) :i* any am\nt ( en]gy may be c>ri$ (f ?r\gh a gas1 ,mr4 ,tesla inf]s t ! be/ way to r5d] h>mless a lightn+ dis*>ge is to af=d x 9 "s way a passage ?r\gh a volume ( gas4 ,! recognition ( "s ( ! above facts has a be>+ ^u f>-rea*+ sci5tific inve/igations 9 :i* extremely high frequ5cies & pot5tials are us$4 ,9 su* cases ! air is an important factor to be consid]$4 ,s1 = in/ance1 if two wires are atta*$ to ! t]m9als ( ! coil1 & ! /ream]s issue f !m1 !re is dissipation ( en]gy 9 ! =m ( heat & light1 & ! wires behave l a cond5s] ( l>g] capacity4 ,if ! wires be imm]s$ 9 oil1 ! dissipation ( en]gy is prev5t$1 or at lea/ r$uc$1 & ! app>5t capacity is dim9i%$4 ,! action ( ! air w\ld seem to make x v difficult to tell1 f ! measur$ or comput$ capacity ( a cond5s] 9 :i* ! air is act$ ^u1 its actual capacity or vibration p]iod1 especially if ! cond5s] is ( v small surface & is *>g$ to a v high pot5tial4 ,z _m important results are dep5dant ^u ! correctness ( ! e/imation ( ! vibration p]iod1 ?is subject dem&s ! mo/ c>eful scrut9y ( inve/igators4 ,9 ,leyd5 j>s ! loss due to ! pres5ce ( air is comp>atively small1 pr9cipally on acc\nt ( ! great surface ( ! coat+s & ! small ext]nal action1 b if !re are /ream]s on ! top1 ! loss may be consid]able1 & ! p]iod ( vibration is affect$4 ,9 a resonator1 ! d5sity is small1 b ! frequ5cy is extreme1 & may introduce a consid]able error4 ,x appe>s c]ta91 at any rate1 t ! p]iods ( vibration ( a *>g$ body 9 a gase\s & 9 a cont9u\s m$ium1 su* z oil1 are diff]5t1 on acc\nt ( ! action ( ! =m]1 z expla9$4 ,ano!r fact recogniz$1 :i* is ( "s consequ5ce1 is1 t 9 simil> inve/igations ! g5]al consid]ations ( /atic scre5+ are n applicable :5 a gase\s m$ium is pres5t4 ,?is is evid5t f ! foll[+ exp]im5t3--,a %ort & wide glass tube is tak5 & cov]$ ) a sub/antial coat+ ( bronze p[d]1 b>ely all[+ ! light to %9e a little ?r\gh4 ,! tube is highly exhau/$ & susp5d$ on a metallic clasp f ! end ( a wire4 ,:5 ! wire is connect$ ) "o ( ! t]m9als ( ! coil1 ! gas inside ( ! tube is light$ 9 spite ( ! metal coat+4 ,"h ! metal evid5tly does n scre5 ! gas inside z x ought to1 ev5 if x be v ?9 & poorly conduct+4 ,yet1 9 a condition ( re/ ! metal coat+1 h[ev] ?91 scre5s ! inside p]fectly4 ,"o ( ! mo/ int]e/+ results arriv$ at 9 pursu+ ^! exp]im5ts1 is ! demon/ration ( ! fact t a gase\s m$ium1 ^u :i* vibration is impress$ by rapid *anges ( electro/atic pot5tial1 is rigid4 ,9 illu/ration ( ?is result an exp]im5t made by ,mr4 ,tesla may by cit$3--,a glass tube ab\t "o in* 9 diamet] & ?ree feet long1 ) outside cond5s] coat+s on ! ends1 0 exhau/$ to a c]ta9 po9t1 :51 ! tube be+ susp5d$ freely f a wire connect+ ! upp] coat+ to "o ( ! t]m9als ( ! coil1 ! dis*>ge appe>$ 9 ! =m ( a lum9\s ?read pass+ ?r\gh ! axis ( ! tube4 ,usually ! ?read 0 %>ply def9$ 9 ! upp] "p ( ! tube & lo/ itself 9 ! l[] "p4 ,:5 a magnet or ! f+] 0 quickly pass$ ne> ! upp] "p ( ! lum9\s ?read1 x 0 br\ght out ( position by magnetic or electro/atic influ5ce1 & a transv]sal vibration l t ( a susp5d$ cord1 ) "o or m di/9ct nodes1 0 set up1 :i* la/$ = a few m9utes & gradually di$ out4 ,by susp5d+ f ! l[] cond5s] coat+ metal plates ( diff]5t sizes1 ! spe$ ( ! vibration 0 v>i$4 ,?is vibration w\ld seem to %[ beyond d\bt t ! ?read possess$ rigidity1 at lea/ to transv]sal displacem5ts4 ,_m exp]im5ts 7 tri$ to demon/rate ?is prop]ty 9 air at ord9>y pressure4 ,?\gh no positive evid5ce has be5 obta9$1 x is ?\ght1 nev]!less1 t a high frequ5cy bru% or /ream]1 if ! frequ5cy c\ld be pu%$ f> en\gh1 w\ld be decid$ly rigid4 ,a small sph]e might !n be mov$ )9 x q freely1 b if ?r[n aga9/ x ! sph]e w\ld reb\nd4 ,an ord9>y flame _c possess rigidity to a m>k$ degree because ! vibration is directionless2 b an electric arc1 x is believ$1 mu/ possess t prop]ty m or less4 ,a lum9\s b& excit$ 9 a bulb by repeat$ dis*>ges ( a ,leyd5 j> mu/ also possess rigidity1 & if de=m$ & sudd5ly releas$ %\ld vibrate4 ,f l consid]ations o!r conclusions ( int]e/ are rea*$4 ,! mo/ probable m$ium fill+ ! space is "o consi/+ ( indep5d5t c>ri]s imm]s$ 9 an insulat+ fluid4 ,if ?r\gh ?is m$ium enorm\s electro/atic /resses are assum$ to act1 :i* v>y rapidly 9 int5sity1 x w\ld all[ ! motion ( a body ?r\gh x1 yet x w\ld be rigid & ela/ic1 al?\gh ! fluid itself might be devoid ( ^! prop]ties4 ,fur!rmore1 on ! assumption t ! indep5d5t c>ri]s are ( any configuration su* t ! fluid resi/ance to motion 9 "o direction is great] ?an 9 ano!r1 a /ress ( t nature w\ld cause ! c>ri]s to arrange !mselves 9 gr\ps1 s9ce !y w\ld turn to ea* o!r _! sides ( ! greate/ electric d5sity1 9 :i* position ! fluid resi/ance to approa* w\ld be small] ?an to rec$+4 ,if 9 a m$ium ( ! above *>act]i/ics a bru% w\ld be =m$ by a /eady pot5tial1 an ex*ange ( ! c>ri]s w\ld g on cont9ually1 & !re w\ld be less c>ri]s p] unit ( volume 9 ! bru% ?an 9 ! space at "s di/ance f ! electrode1 ?is correspond+ to r>efaction4 ,if ! pot5tial 7 rapidly *ang+1 ! result w\ld be v diff]5t2 ! high] ! frequ5cy ( ! pulses1 ! sl[] w\ld be ! ex*ange ( ! c>ri]s2 f9ally1 ! motion ( translation ?r\gh measurable space w\ld cease1 &1 ) a suffici5tly high frequ5cy & int5sity ( ! /ress1 ! c>ri]s w\ld be drawn t[>ds ! electrode1 & compression w\ld result4 ,an int]e/+ feature ( ^! high frequ5cy curr5ts is t !y all[ ( op]at+ all k9ds ( devices by connect+ ! device ) only "o lead+ wire to ! electric s\rce4 ,9 fact1 "u c]ta9 conditions x may be m economical to supply ! electrical en]gy ) "o lead ?an ) two4 ,an exp]im5t ( special int]e/ %[n by ,mr4 ,tesla1 is ! runn+1 by ! use ( only "o insulat$ l9e1 ( a motor op]at+ on ! pr9ciple ( ! rotat+ magnetic field enunciat$ by ,mr4 ,tesla4 ,a simple =m ( su* a motor is obta9$ by w9d+ ^u a lam9at$ iron core a prim>y & close to x a second>y coil1 clos+ ! ends ( ! latt] & plac+ a freely movable metal disc )9 ! influ5ce ( ! mov+ field4 ,! second>y coil may1 h[ev]1 be omitt$4 ,:5 "o ( ! ends ( ! prim>y coil ( ! motor is connect$ to "o ( ! t]m9als ( ! high frequ5cy coil & ! o!r end to an insulat$ metal plate1 :i*1 x %\ld be /at$1 is n absolutely necess>y = ! success ( ! exp]im5t1 ! disc is set 9 rotation4 ,exp]im5ts ( ?is k9d seem to br+ x )9 possibility to op]ate a motor at any po9t ( ! e>?'s surface f a c5tral s\rce1 )\t any connection to ! same except ?r\gh ! e>?4 ,if1 by means ( p[]ful ma*9]y1 rapid v>iations ( ! e>?'s pot5tial 7 produc$1 a gr\nd$ wire rea*+ up to "s height w\ld be trav]s$ by a curr5t :i* c\ld be increas$ by connect+ ! free end ( ! wire to a body ( "s size4 ,! curr5t might be conv]t$ to l[ t5sion & us$ to op]ate a motor or o!r device4 ,! exp]im5t1 :i* w\ld be "o ( great sci5tific int]e/1 w\ld probably be/ succe$ on a %ip at sea4 ,9 ?is mann]1 ev5 if x 7 n possible to op]ate ma*9]y1 intellig5ce might be transmitt$ q c]ta9ly4 ,9 ! c\rse ( ?is exp]im5tal /udy special att5tion 0 devot$ to ! heat+ effects produc$ by ^! curr5ts1 :i* are n only /rik+1 b op5 up ! possibility ( produc+ a m effici5t illum9ant4 ,x is suffici5t to atta* to ! coil t]m9al a ?9 wire or filam5t1 to h ! temp]ature ( ! latt] p]ceptibly rais$4 ,if ! wire or filam5t be enclos$ 9 a bulb1 ! heat+ effect is increas$ by prev5t+ ! circulation ( ! air4 ,if ! air 9 ! bulb be /rongly compress$1 ! displacem5ts are small]1 ! impacts less viol5t1 & ! heat+ effect is dim9i%$4 ,on ! contr>y1 if ! air 9 ! bulb be exhau/$1 an inclos$ lamp filam5t is br\ght to inc&esc5ce1 & any am\nt ( light may ?us be produc$4 ,! heat+ ( ! inclos$ lamp filam5t dep5ds on s _m ?+s ( a diff]5t nature1 t x is difficult to give a g5]ally applicable rule "u :i* ! maximum heat+ occurs4 ,z reg>ds ! size ( ! bulb1 x is asc]ta9$ t at ord9>y or only slightly diff]+ atmosph]ic pressures1 :5 air is a good insulator1 ! filam5t is heat$ m 9 a small bulb1 because ( ! bett] conf9em5t ( heat 9 ?is case4 ,at l[] pressures1 :5 air becomes conduct+1 ! heat+ effect is great] 9 a l>ge bulb1 b at excessively high degrees ( exhau/ion !re seems to be1 beyond a c]ta9 & r small size ( ! vessel1 no p]ceptible diff]5ce 9 ! heat+4 ,! %ape ( ! vessel is also ( "s importance1 & x has be5 f\nd ( advantage = reasons ( economy to employ a sph]ical bulb ) ! electrode m\nt$ 9 its c5tre1 :]e ! reb\nd+ molecules collide4 ,x is desirable on acc\nt ( economy t all ! en]gy suppli$ to ! bulb f ! s\rce %\ld rea* )\t loss ! body to be heat$4 ,! loss 9 convey+ ! en]gy f ! s\rce to ! body may be r$uc$ by employ+ ?9 wires heavily coat$ ) insulation1 & by ! use ( electro/atic scre5s4 ,x is to be rem>k$1 t ! scre5 _c be connect$ to ! gr\nd z "u ord9>y conditions4 ,9 ! bulb itself a l>ge portion ( ! en]gy suppli$ may be lo/ by molecul> bomb>dm5t aga9/ ! wire connect+ ! body to be heat$ ) ! s\rce4 ,consid]able improvem5t 0 effect$ by cov]+ ! glass /em conta9+ ! wire ) a closely fitt+ conduct+ tube4 ,?is tube is made to project a little above ! glass1 & prev5ts ! crack+ ( ! latt] ne> ! heat$ body4 ,! effectiv5ess ( ! conduct+ tube is limit$ to v high degrees ( exhau/ion4 ,x dim9i%es ! en]gy lo/ 9 bomb>dm5t = two reasons2 fir/1 ! *>ge giv5 up by ! atoms spreads ov] a great] area1 & h5ce ! electric d5sity at any po9t is small1 & ! atoms are repell$ ) less en]gy ?an if !y w\ld /rike aga9/ a good insulator2 secondly1 z ! tube is electrifi$ by ! atoms :i* fir/ come 9 contact ) x1 ! progress ( ! foll[+ atoms aga9/ ! tube is m or less *eck$ by ! repulsion :i* ! electrifi$ tube mu/ ex]t ^u ! simil>ly electrifi$ atoms4 ,?is1 x is ?\ght1 expla9s :y ! dis*>ge ?r\gh a bulb is e/abli%$ ) mu* great] facility :5 an insulator1 ?an :5 a conductor1 is pres5t4 ,dur+ ! inve/igations a great _m bulbs ( diff]5t con/ruction1 ) electrodes ( diff]5t mat]ial1 7 exp]im5t$ ^u1 & a numb] ( obs]vations ( int]e/ 7 made4 ,mr4 ,tesla has f\nd t ! det]ioration ( ! electrode is ! less1 ! high] ! frequ5cy4 ,?is 0 to be expect$1 z !n ! heat+ is effect$ by _m small impacts1 in/ead by few] & m viol5t ones1 :i* quickly %att] ! /ructure4 ,! det]ioration is also small] :5 ! vibration is h>monic4 ,?us an electrode1 ma9ta9$ at a c]ta9 degree ( heat1 la/s mu* long] ) curr5ts obta9$ f an alt]nator1 ?an ) ^? obta9$ by means ( a disruptive dis*>ge4 ,"o ( ! mo/ durable electrodes 0 obta9$ f /rongly compress$ c>borundum1 :i* is a k9d ( c>bon rec5tly produc$ by ,mr4 ,e4 ,g4 ,a*eson1 ( ,monongahela ,city1 ,pa4 ,f exp]i5ce1 x is inf]r$1 t to be mo/ durable1 ! electrode %\ld be 9 ! =m ( a sph]e ) a highly poli%$ surface4 ,9 "s bulbs refractory bodies 7 m\nt$ 9 a c>bon cup & put "u ! molecul> impact4 ,x 0 obs]v$ 9 su* exp]im5ts t ! c>bon cup 0 heat$ at fir/1 until a high] temp]ature 0 rea*$2 !n mo/ ( ! bomb>dm5t 0 direct$ aga9/ ! refractory body1 & ! c>bon 0 reliev$4 ,9 g5]al1 :5 diff]5t bodies 7 m\nt$ 9 ! bulb1 ! h>de/ fusible w\ld be reliev$1 & w\ld rema9 at a consid]ably l[] temp]ature4 ,?is 0 necessitat$ by ! fact t mo/ ( ! en]gy suppli$ w\ld f9d its way ?r\gh ! body :i* 0 m easily fus$ or evaporat$4 ,curi\sly en\gh x appe>$ 9 "s ( ! exp]im5ts made1 t a body 0 fus$ 9 a bulb "u ! molecul> impact by evolution ( less light ?an :5 fus$ by ! application ( heat 9 ord9>y ways4 ,?is may be ascrib$ to a loos5+ ( ! /ructure ( ! body "u ! viol5t impacts & *ang+ /resses4 ,"s exp]im5ts seem to indicate t "u c]ta9 conditions a body1 conduct+ or nonconduct+1 may1 :5 bomb>d$1 emit light1 :i* to all appe>ances is due to phosphoresc5ce1 b may 9 reality be caus$ by ! inc&esc5ce ( an inf9itesimal lay]1 ! mean temp]ature ( ! body be+ comp>atively small4 ,su* might be ! case if ea* s+le rhy?mical impact 7 capable ( in/antane\sly excit+ ! ret9a1 & ! rhy?m 7 j high en\gh to cause a cont9u\s impression 9 ! eye4 ,accord+ to ?is view1 a coil op]at$ by disruptive dis*>ge w\ld be em95tly adapt$ to produce su* a result1 & x is f\nd by exp]i5ce t its p[] ( excit+ phosphoresc5ce is extraord9>ily great4 ,x is capable ( excit+ phosphoresc5ce at comp>atively l[ degrees ( exhau/ion1 & also projects %ad[s at pressures f> great] ?an ^? at :i* ! mean free pa? is comp>able to ! dim5sions ( ! vessel4 ,! latt] obs]vation is ( "s importance1 inasmu* z x may modify ! g5]ally accept$ views 9 reg>d to ! radiant /ate ph5om5a4 ,a ?\ght :i* e>ly & naturally sugge/$ itself to ,mr4 ,tesla1 0 to utilize ! great inductive effects ( high frequ5cy curr5ts to produce light 9 a seal$ glass vessel )\t ! use ( lead+ 9 wires4 ,accord+ly1 _m bulbs 7 con/ruct$ 9 :i* ! en]gy necess>y to ma9ta9 a button or filam5t at high inc&esc5ce1 0 suppli$ ?r\gh ! glass by ei!r electro/atic or electrodynamic induction4 ,x 0 easy to regulate ! int5sity ( ! light emitt$ by means ( an ext]nally appli$ cond5s] coat+ connect$ to an insulat$ plate1 or simply by means ( a plate atta*$ to ! bulb :i* at ! same "t p]=m$ ! function ( a %ade4 ,a subject ( exp]im5t1 :i* has be5 exhau/ively treat$ 9 ,engl& by ,pr(4 ,j4 ,j4 ,?omson1 has be5 foll[$ up indep5d5tly by ,mr4 ,tesla f ! beg9n+ ( ?is /udy1 namely1 to excite by electrodynamic induction a lum9\s b& 9 a clos$ tube or bulb4 ,9 obs]v+ ! behavior ( gases1 & ! lum9\s ph5om5a obta9$1 ! importance ( ! electro/atic effects 0 not$ & x appe>$ desirable to produce enorm\s pot5tial diff]5ces1 alt]nat+ ) extreme rapidity4 ,exp]im5ts 9 ?is direction l$ to "s ( ! mo/ int]e/+ results arriv$ at 9 ! c\rse ( ^! inve/igations4 ,x 0 f\nd t by rapid alt]nations ( a high electro/atic pot5tial1 exhau/$ tubes c\ld be light$ at consid]able di/ances f a conductor connect$ to a prop]ly con/ruct$ coil1 & t x 0 practicable to e/abli% ) ! coil an alt]nat+ electro/atic field1 act+ ?r\gh ! :ole room & light+ a tube :]ev] x 0 plac$ )9 ! f\r walls4 ,phosphoresc5t bulbs may be excit$ 9 su* a field1 & x is easy to regulate ! effect by connect+ to ! bulb a small insulat$ metal plate4 ,x 0 likewise possible to ma9ta9 a filam5t or button m\nt$ 9 a tube at bright inc&esc5ce1 &1 9 "o exp]im5t1 a mica vane 0 spun by ! inc&esc5ce ( a plat9um wire4 ,com+ n[ to ! lecture deliv]$ 9 ,philadelphia & ,/4 ,l\is1 x may be rem>k$ t to ! sup]ficial read]1 ,mr4 ,tesla's introduction1 deal+ ) ! importance ( ! eye1 might appe> z a digression1 b ! ?\ghtful read] w f9d !re9 mu* food = m$itation & speculation4 ,?r\gh\t 8 disc\rse "o c trace ,mr4 ,tesla's ef=t to pres5t 9 a popul> way ?\ghts & views on ! electrical ph5om5a :i* h 9 rec5t ye>s captivat$ ! sci5tific _w1 b ( :i* ! g5]al public has ev5 yet m]ely receiv$ an inkl+4 ,mr4 ,tesla also dwells r ext5sively on 8 well-kn[n me?od ( high-frequ5cy conv]sion2 & ! l>ge am\nt ( detail in=mation w be gratefully receiv$ by /ud5ts & exp]im5t]s 9 ?is virg9 field4 ,! employm5t ( apt analogies 9 expla9+ ! fundam5tal pr9ciples involv$ makes x easy = all to ga9 a cle> idea ( _! nature4 ,aga91 ! ease ) :i*1 ?anks to ,mr4 ,tesla's ef=ts1 ^! high-frequ5cy curr5ts may n[ be obta9$ f circuits c>ry+ almo/ any k9d ( curr5t1 _c fail to result 9 an ext5sive broad5+ ( ?is field ( rese>*1 :i* (f]s s _m possibilities4 ,mr4 ,tesla1 true philosoph] z he is1 does n hesitate to po9t out defects 9 "s ( 8 me?ods1 & indicates ! l9es :i* to him seem ! mo/ promis+4 ,p>ticul> /ress is laid by him ^u ! employm5t ( a m$ium 9 :i* ! dis*>ge electrodes %\ld be imm]s$ 9 ord] t ?is me?od ( conv]sion may be br\ght to ! highe/ p]fection4 ,he has evid5tly tak5 pa9s to give z mu* useful in=mation z possible to ^? :o wi% to foll[ 9 8 pa?1 z he %[s 9 detail ! circuit arrangem5ts to be adopt$ 9 all ord9>y cases met ) 9 practice1 & al?\gh "s ( ^! me?ods 7 describ$ by him two ye>s be=e1 ! additional in=mation is /ill timely & welcome4 ,9 8 exp]im5ts he dwells fir/ on "s ph5om5a produc$ by electro/atic =ce1 :i* he consid]s 9 ! light ( mod]n !ories to be ! mo/ important =ce 9 nature = u to inve/igate4 ,at ! v outset he %[s a /rik+ly novel exp]im5t illu/rat+ ! effect ( a rapidly v>y+ electro/atic =ce 9 a gase\s m$ium1 by t\*+ ) "o h& "o ( ! t]m9als ( a #bjj1jjj volt trans=m] & br++ ! o!r h& to ! opposite t]m9al4 ,! p[]ful /ream]s :i* issu$ f 8 h& & a/oni%$ 8 audi5ces =m$ a capital illu/ration ( "s ( ! views advanc$1 & af=d$ ,mr4 ,tesla an opportunity ( po9t+ out ! true reasons :y1 ) ^! curr5ts1 su* an am\nt ( en]gy c be pass$ ?r\gh ! body ) impunity4 ,he !n %[$ by exp]im5t ! diff]5ce betwe5 a /eady & a rapidly v>y+ =ce ^u ! dielectric4 ,?is diff]5ce is mo/ /rik+ly illu/rat$ 9 ! exp]im5t 9 :i* a bulb atta*$ to ! end ( a wire 9 connection ) "o ( ! t]m9als ( ! trans=m] is ruptur$1 al?\gh all extrane\s bodies are remote f ! bulb4 ,he next illu/rates h[ me*anical motions are produc$ by a v>y+ electro/atic =ce act+ ?r\gh a gase\s m$ium4 ,! importance ( ! action ( ! air is p>ticul>ly illu/rat$ by an int]e/+ exp]im5t4 ,tak+ up ano!r class ( ph5om5a1 namely1 ^? ( dynamic electricity1 ,mr4 ,tesla produc$ 9 a numb] ( exp]im5ts a v>iety ( effects by ! employm5t ( only a s+le wire ) ! evid5t int5t ( impress+ ^u 8 audi5ce ! idea t electric vibration or curr5t c be transmitt$ ) ease1 )\t any return circuit2 also h[ curr5ts s transmitt$ c be conv]t$ & us$ = _m practical purposes4 ,a numb] ( exp]im5ts are !n %[n1 illu/rat+ ! effects ( frequ5cy1 self-induction & capacity2 !n a numb] ( ways ( op]at+ motive & o!r devices by ! use ( a s+le lead4 ,a numb] ( novel imp$ance ph5om5a are also %[n :i* _c fail to ar\se int]e/4 ,mr4 ,tesla next dwelt ^u a subject :i* he ?9ks ( great importance1 t is1 electrical resonance1 :i* he expla9$ 9 a popul> way4 ,he express$ 8 firm conviction t by obs]v+ prop] conditions1 intellig5ce1 & possibly ev5 p[]1 c be transmitt$ ?r\gh ! m$ium or ?r\gh ! e>?2 & he consid]s ?is problem wor?y ( s]i\s & imm$iate consid]ation4 ,com+ n[ to ! light ph5om5a 9 p>ticul>1 he illu/rat$ ! f\r di/9ct k9ds ( ^! ph5om5a 9 an orig9al way1 :i* to _m mu/ h be5 a revelation4 ,mr4 ,tesla attributes ^! light effects to molecul> or atomic impacts produc$ by a v>y+ electro/atic /ress 9 a gase\s m$ium4 ,he illu/rat$ 9 a s]ies ( novel exp]im5ts ! effect ( ! gas surr\nd+ ! conductor & %[s beyond a d\bt t ) high frequ5cy & high pot5tial curr5ts1 ! surr\nd+ gas is ( p>am\nt importance 9 ! heat+ ( ! conductor4 ,he attributes ! heat+ p>tially to a conduction curr5t & p>tially to bomb>dm5t1 & demon/rates t 9 _m cases ! heat+ may be practically due to ! bomb>dm5t alone4 ,he po9t$ out also t ! sk9 effect is l>gely modifi$ by ! pres5ce ( ! gas or ( an atomic m$ium 9 g5]al4 ,he %[$ also "s int]e/+ exp]im5ts 9 :i* ! effect ( convection is illu/rat$4 ,probably "o ( ! mo/ curi\s exp]im5ts 9 ?is connection is t 9 :i* a ?9 plat9um wire /ret*$ along ! axis ( an exhau/$ tube is br\ght to inc&esc5ce at c]ta9 po9ts correspond+ to ! position ( ! /riae1 :ile at o!rs x rema9s d>k4 ,?is exp]im5t ?r[s an int]e/+ light ^u ! nature ( ! /riae & may lead to important revelations4 ,mr4 ,tesla also demon/rat$ ! dissipation ( en]gy ?r\gh an atomic m$ium & dwelt ^u ! behavior ( vacu\s space 9 convey+ heat1 & 9 ?is connection %[$ ! curi\s behavior ( an electrode /ream1 f :i* he concludes t ! molecules ( a gas probably _c be act$ ^u directly at measurable di/ances4 ,mr4 ,tesla summ>iz$ ! *ief results arriv$ at 9 pursu+ 8 inve/igations 9 a mann] :i* w s]ve z a valuable guide to all :o may engage 9 ?is "w4 ,p]haps mo/ int]e/ w c5tre on 8 g5]al /atem5ts reg>d+ ! ph5om5a ( phosphoresc5ce1 ! mo/ important fact reveal$ 9 ?is direction be+ t :5 excit+ a phosphoresc5t bulb a c]ta9 def9ite pot5tial gives ! mo/ economical result4 ,! lectures w n[ be pres5t$ 9 ! ord] ( _! date ( deliv]y4 ,,*apt] ,,xxvi4 ,,exp]im5ts ,,) ,,alt]nate ,,curr5ts ,,( ,,v ,,high ,,frequ5cy ,,& ,,_! ,,application ,,to ,,me?ods ,,( ,,artificial ,,illum9ation4#a #a ,a lecture deliv]$ be=e ! ,am]ican ,in/itute ( ,electrical ,eng9e]s1 at ,columbia ,college1 ,n4 ,y41 ,may #bj1 #ahia4 ,!re is no subject m captivat+1 m wor?y ( /udy1 ?an nature4 ,to und]/& ?is great me*anism1 to discov] ! =ces :i* are active1 & ! laws :i* gov]n !m1 is ! highe/ aim ( ! intellect ( man4 ,nature has /or$ up 9 ! univ]se inf9ite en]gy4 ,! et]nal recipi5t & transmitt] ( ?is inf9ite en]gy is ! e!r4 ,! recognition ( ! exi/5ce ( e!r1 & ( ! functions x p]=ms1 is "o ( ! mo/ important results ( mod]n sci5tific rese>*4 ,! m]e ab&on+ ( ! idea ( action at a di/ance1 ! assumption ( a m$ium p]vad+ all space & connect+ all gross matt]1 has fre$ ! m9ds ( ?9k]s ( an ev] pres5t d\bt1 &1 by op5+ a new horizon--new & un=ese5 possibilities--has giv5 fre% int]e/ to ph5om5a ) :i* we are famili> ( old4 ,x has be5 a great /ep t[>ds ! und]/&+ ( ! =ces ( nature & _! multifold manife/ations to our s5ses4 ,x has be5 = ! enlight5$ /ud5t ( physics :at ! und]/&+ ( ! me*anism ( ! fire>m or ( ! /eam eng9e is = ! b>b>ian4 ,ph5om5a ^u :i* we us$ to look z wond]s baffl+ explanation1 we n[ see 9 a diff]5t light4 ,! sp>k ( an induction coil1 ! gl[ ( an inc&esc5t lamp1 ! manife/ations ( ! me*anical =ces ( curr5ts & magnets are no long] beyond our grasp2 in/ead ( ! incompreh5sible1 z be=e1 _! obs]vation sugge/s n[ 9 our m9ds a simple me*anism1 & al?\gh z to its precise nature all is /ill conjecture1 yet we "k t ! tru? _c be mu* long] hidd51 & in/9ctively we feel t ! und]/&+ is dawn+ ^u u4 ,we /ill admire ^! beautiful ph5om5a1 ^! /range =ces1 b we are helpless no long]2 we c 9 a c]ta9 measure expla9 !m1 acc\nt = !m1 & we are hopeful ( f9ally succe$+ 9 unravel+ ! my/]y :i* surr\nds !m4 ,9 h[ f> we c und]/& ! _w ar\nd u is ! ultimate ?\ght ( e /ud5t ( nature4 ,! co>s5ess ( our s5ses prev5ts u f recogniz+ ! ult]ior con/ruction ( matt]1 & a/ronomy1 ?is gr&e/ & mo/ positive ( natural sci5ces1 c only tea* u some?+ t happ5s1 z x 71 9 our imm$iate neighborhood3 ( ! remot] portions ( ! b\ndless univ]se1 ) its numb]less />s & suns1 we "k no?+4 ,b f> beyond ! limit ( p]ception ( our s5ses ! _s /ill c guide u1 & s we may hope t ev5 ^! unkn[n worlds--inf9itely small & great--may 9 a measure become kn[n to u4 ,/ill1 ev5 if ?is k %\ld rea* u1 ! se>*+ m9d w f9d a b>ri]1 p]haps =ev] unsurpassable1 to ! true recognition ( t :i* seems to be1 ! m]e appe>ance ( :i* is ! only & sl5d] basis ( all our philosophy4 ,( all ! =ms ( nature's immeasurable1 all-p]vad+ en]gy1 :i* ev] & ev] *ang+ & mov+1 l a s\l animates ! in]t univ]se1 electricity & magnetism are p]haps ! mo/ fasc9at+4 ,! effects ( gravitation1 ( heat & light we obs]ve daily1 & soon we get accu/om$ to !m1 & soon !y lose = u ! "* ( ! m>vel\s & wond]ful2 b electricity & magnetism1 ) _! s+ul> relation%ip1 ) _! seem+ly dual "*1 unique among ! =ces 9 nature1 ) _! ph5om5a ( attractions1 repulsions & rotations1 /range manife/ations ( my/]i\s ag5ts1 /imulate & excite ! m9d to ?\ght & rese>*4 ,:at is electricity1 & :at is magnetism8 ,^! que/ions h be5 ask$ aga9 & aga94 ,! mo/ able intellects h ceaselessly wre/l$ ) ! problem2 /ill ! "q has n z yet be5 fully answ]$4 ,b :ile we _c ev5 to-day /ate :at ^! s+ul> =ces are1 we h made good headway t[>ds ! solution ( ! problem4 ,we are n[ confid5t t electric & magnetic ph5om5a are attributable to e!r1 & we are p]haps ju/ifi$ 9 say+ t ! effects ( /atic electricity are effects ( e!r "u /ra91 & ^? ( dynamic electricity & electro-magnetism effects ( e!r 9 motion4 ,b ?is /ill leaves ! "q1 z to :at electricity & magnetism are1 unansw]$4 ,fir/1 we naturally inquire1 ,:at is electricity1 & is !re su* a ?+ z electricity8 ,9 int]pret+ electric ph5om5a1 we may speak ( electricity or ( an electric condition1 /ate or effect4 ,if we speak ( electric effects we mu/ di/+ui% two su* effects1 opposite 9 "* & neutraliz+ ea* o!r1 z obs]vation %[s t two su* opposite effects exi/4 ,?is is unavoidable1 = 9 a m$ium ( ! prop]ties ( e!r1 we _c possibly ex]t a /ra91 or produce a displacem5t or motion ( any k9d1 )\t caus+ 9 ! surr\nd+ m$ium an equival5t & opposite effect4 ,b if we speak ( electricity1 mean+ a ?+1 we mu/1 ,i ?9k1 ab&on ! idea ( two electricities1 z ! exi/5ce ( two su* ?+s is highly improbable4 ,= h[ c we imag9e t !re %\ld be two ?+s1 equival5t 9 am\nt1 alike 9 _! prop]ties1 b ( opposite "*1 bo? cl++ to matt]1 bo? attract+ & completely neutraliz+ ea* o!r8 ,su* an assumption1 ?\gh sugge/$ by _m ph5om5a1 ?\gh mo/ conv5i5t = expla9+ !m1 has little to comm5d x4 ,if !re is su* a ?+ z electricity1 !re c be only "o su* ?+1 & excess & want ( t "o ?+1 possibly2 b m probably its condition det]m9es ! positive & negative "*4 ,! old !ory ( ,frankl91 ?\gh fall+ %ort 9 "s respects1 is1 f a c]ta9 po9t ( view1 aft] all1 ! mo/ plausible "o4 ,/ill1 9 spite ( ?is1 ! !ory ( ! two electricities is g5]ally accept$1 z x app>5tly expla9s electric ph5om5a 9 a m satisfactory mann]4 ,b a !ory :i* bett] expla9s ! facts is n necess>ily true4 ,+5i\s m9ds w inv5t !ories to suit obs]vation1 & almo/ e indep5d5t ?9k] has 8 own views on ! subject4 ,x is n ) ! object ( advanc+ an op9ion1 b ) ! desire ( acqua9t+ y bett] ) "s ( ! results1 :i* ,i w describe1 to %[ y ! reason+ ,i h foll[$1 ! dep>tures ,i h made--t ,i v5ture to express1 9 a few words1 ! views & convictions :i* h l$ me to ^! results4 ,i adh]e to ! idea t !re is a ?+ :i* we h be5 9 ! habit ( call+ electricity4 ,! "q is1 ,:at is t ?+8 or1 ,:at1 ( all ?+s1 ! exi/5ce ( :i* we "k1 h we ! be/ reason to call electricity8 ,we "k t x acts l an incompressible fluid2 t !re mu/ be a con/ant quantity ( x 9 nature2 t x c be nei!r produc$ nor de/roy$2 &1 :at is m important1 ! electro-magnetic !ory ( light & all facts obs]v$ tea* u t electric & e!r ph5om5a are id5tical4 ,! idea at once sugge/s itself1 !re=e1 t electricity might be call$ e!r4 ,9 fact1 ?is view has 9 a c]ta9 s5se be5 advanc$ by ,dr4 ,lodge4 ,8 int]e/+ "w has be5 read by ev]yone & _m h be5 conv9c$ by 8 argum5ts4 ,8 great ability & ! int]e/+ nature ( ! subject1 keep ! read] spellb\nd2 b :5 ! impressions fade1 "o realizes t he has to deal only ) +5i\s explanations4 ,i mu/ confess1 t ,i _c believe 9 two electricities1 mu* less 9 a d\bly-con/itut$ e!r4 ,! puzzl+ behavior ( ! e!r z a solid to waves ( light & heat1 & z a fluid to ! motion ( bodies ?r\gh x1 is c]ta9ly expla9$ 9 ! mo/ natural & satisfactory mann] by assum+ x to be 9 motion1 z ,sir ,william ,?omson has sugge/$2 b reg>dless ( ?is1 !re is no?+ :i* w\ld enable u to conclude ) c]ta9ty t1 :ile a fluid is n capable ( transmitt+ transv]se vibrations ( a few hundr$ or ?\s& p] second1 x might n be capable ( transmitt+ su* vibrations :5 !y range into hundr$s ( million millions p] second4 ,nor c anyone prove t !re are transv]se e!r waves emitt$ f an alt]nate curr5t ma*9e1 giv+ a small numb] ( alt]nations p] second2 to su* sl[ di/urbances1 ! e!r1 if at re/1 may behave z a true fluid4 ,return+ to ! subject1 & be>+ 9 m9d t ! exi/5ce ( two electricities is1 to say ! lea/1 highly improbable1 we mu/ rememb]1 t we h no evid5ce ( electricity1 nor c we hope to get x1 unless gross matt] is pres5t4 ,electricity1 !re=e1 _c be call$ e!r 9 ! broad s5se ( ! t]m2 b no?+ w\ld seem to /& 9 ! way ( call+ electricity e!r associat$ ) matt]1 or b\nd e!r2 or1 9 o!r words1 t ! s-call$ /atic *>ge ( ! molecule is e!r associat$ 9 "s way ) ! molecule4 ,look+ at x 9 t light1 we w\ld be ju/ifi$ 9 say+1 t electricity is conc]n$ 9 all molecul> actions4 ,n[1 precisely :at ! e!r surr\nd+ ! molecules is1 :]e9 x diff]s f e!r 9 g5]al1 c only be conjectur$4 ,x _c diff] 9 d5sity1 e!r be+ incompressible3 x mu/1 !re=e1 be "u "s /ra9 or 9 motion1 & ! latt] is ! mo/ probable4 ,to und]/& its functions1 x w\ld be necess>y to h an exact idea ( ! physical con/ruction ( matt]1 ( :i*1 ( c\rse1 we c only =m a m5tal picture4 ,b ( all ! views on nature1 ! "o :i* assumes "o matt] & "o =ce1 & a p]fect uni=mity ?r\gh\t1 is ! mo/ sci5tific & mo/ likely to be true4 ,an inf9itesimal _w1 ) ! molecules & _! atoms sp9n+ & mov+ 9 orbits1 9 mu* ! same mann] z cele/ial bodies1 c>ry+ ) !m & probably sp9n+ ) !m e!r1 or 9 o!r words1 c>ry+ ) !m /atic *>ges1 seems to my m9d ! mo/ probable view1 & "o :i*1 9 a plausible mann]1 acc\nts = mo/ ( ! ph5om5a obs]v$4 ,! sp9n+ ( ! molecules & _! e!r sets up ! e!r t5sions or electro/atic /ra9s2 ! equalization ( e!r t5sions sets up e!r motions or electric curr5ts1 & ! orbital movem5ts produce ! effects ( electro & p]man5t magnetism4 ,ab\t fifte5 ye>s ago1 ,pr(4 ,r[l& demon/rat$ a mo/ int]e/+ & important fact1 namely1 t a /atic *>ge c>ri$ ar\nd produces ! effects ( an electric curr5t4 ,leav+ out ( consid]ation ! precise nature ( ! me*anism1 :i* produces ! attraction & repulsion ( curr5ts1 & conceiv+ ! electro/atically *>g$ molecules 9 motion1 ?is exp]im5tal fact gives u a fair idea ( magnetism4 ,we c conceive l9es or tubes ( =ce :i* physically exi/1 be+ =m$ ( r[s ( direct$ mov+ molecules2 we c see t ^! l9es mu/ be clos$1 t !y mu/ t5d to %ort5 & exp&1 etc4 ,x likewise expla9s 9 a reasonable way1 ! mo/ puzzl+ ph5om5on ( all1 p]man5t magnetism1 &1 9 g5]al1 has all ! beauties ( ! ,amp]e !ory )\t possess+ ! vital defect ( ! same1 namely1 ! assumption ( molecul> curr5ts4 ,)\t enl>g+ fur!r ^u ! subject1 ,i w\ld say1 t ,i look ^u all electro/atic1 curr5t & magnetic ph5om5a z be+ due to electro/atic molecul> =ces4 ,! prec$+ rem>ks ,i h deem$ necess>y to a full und]/&+ ( ! subject z x pres5ts itself to my m9d4 ,( all ^! ph5om5a ! mo/ important to /udy are ! curr5t ph5om5a1 on acc\nt ( ! already ext5sive & ev]-gr[+ use ( curr5ts = indu/rial purposes4 ,x is n[ a c5tury s9ce ! fir/ practical s\rce ( curr5t 0 produc$1 &1 ev] s9ce1 ! ph5om5a :i* accompany ! fl[ ( curr5ts h be5 dilig5tly /udi$1 & ?r\gh ! untir+ ef=ts ( sci5tific m5 ! simple laws :i* gov]n !m h be5 discov]$4 ,b ^! laws are f\nd to hold good only :5 ! curr5ts are ( a /eady "*4 ,:5 ! curr5ts are rapidly v>y+ 9 /r5g?1 q diff]5t ph5om5a1 (t5 unexpect$1 pres5t !mselves1 & q diff]5t laws hold good1 :i* ev5 n[ h n be5 det]m9$ z fully z is desirable1 ?\gh ?r\gh ! "w1 pr9cipally1 ( ,engli% sci5ti/s1 en\gh k has be5 ga9$ on ! subject to enable u to treat simple cases :i* n[ pres5t !mselves 9 daily practice4 ,! ph5om5a :i* are peculi> to ! *ang+ "* ( ! curr5ts are greatly exalt$ :5 ! rate ( *ange is increas$1 h5ce ! /udy ( ^! curr5ts is consid]ably facilitat$ by ! employm5t ( prop]ly con/ruct$ app>atus4 ,x 0 ) ?is & o!r objects 9 view t ,i con/ruct$ alt]nate curr5t ma*9es capable ( giv+ m ?an two million rev]sals ( curr5t p] m9ute1 & to ?is circum/ance x is pr9cipally due1 t ,i am able to br+ to y\r att5tion "s ( ! results ?us f> rea*$1 :i* ,i hope w prove to be a /ep 9 advance on acc\nt ( _! direct be>+ ^u "o ( ! mo/ important problems1 namely1 ! production ( a practical & effici5t s\rce ( light4 ,! /udy ( su* rapidly alt]nat+ curr5ts is v int]e/+4 ,ne>ly e exp]im5t discloses some?+ new4 ,_m results may1 ( c\rse1 be pr$ict$1 b _m m are un=ese54 ,! exp]im5t] makes _m int]e/+ obs]vations4 ,= in/ance1 we take a piece ( iron & hold x aga9/ a magnet4 ,/>t+ f l[ alt]nations & runn+ up high] & high] we feel ! impulses succe$ ea* o!r fa/] & fa/]1 get weak] & weak]1 & f9ally disappe>4 ,we !n obs]ve a cont9u\s pull2 ! pull1 ( c\rse1 is n cont9u\s2 x only appe>s s to u2 our s5se ( t\* is imp]fect4 ,we may next e/abli% an arc betwe5 ! electrodes & obs]ve1 z ! alt]nations rise1 t ! note :i* accompanies alt]nat+ arcs gets %rill] & %rill]1 gradually weak5s1 & f9ally ceases4 ,! air vibrations1 ( c\rse1 cont9ue1 b !y are too weak to be p]ceiv$2 our s5se ( he>+ fails u4 ,we obs]ve ! small physiological effects1 ! rapid heat+ ( ! iron cores & conductors1 curi\s inductive effects1 int]e/+ cond5s] ph5om5a1 & /ill m int]e/+ light ph5om5a ) a high t5sion induction coil4 ,all ^! exp]im5ts & obs]vations w\ld be ( ! greate/ int]e/ to ! /ud5t1 b _! description w\ld lead me too f> f ! pr9cipal subject4 ,p>tly = ?is reason1 & p>tly on acc\nt ( _! va/ly great] importance1 ,i w conf9e myself to ! description ( ! light effects produc$ by ^! curr5ts4 ,9 ! exp]im5ts to ?is end a high t5sion induction coil or equival5t app>atus = conv]t+ curr5ts ( comp>atively l[ into curr5ts ( high t5sion is us$4 ,if y w be suffici5tly int]e/$ 9 ! results ,i %all describe z to ent] into an exp]im5tal /udy ( ?is subject2 if y w be conv9c$ ( ! tru? ( ! argum5ts ,i %all advance--y\r aim w be to produce high frequ5cies & high pot5tials2 9 o!r words1 p[]ful electro/atic effects4 ,y w !n enc\nt] _m difficulties1 :i*1 if completely ov]come1 w\ld all[ u to produce truly wond]ful results4 ,fir/ w be met ! difficulty ( obta9+ ! requir$ frequ5cies by means ( me*anical app>atus1 &1 if !y be obta9$ o!rwise1 ob/acles ( a diff]5t nature w pres5t !mselves4 ,next x w be f\nd difficult to provide ! requisite insulation )\t consid]ably increas+ ! size ( ! app>atus1 = ! pot5tials requir$ are high1 &1 ow+ to ! rapidity ( ! alt]nations1 ! insulation pres5ts peculi> difficulties4 ,s1 = in/ance1 :5 a gas is pres5t1 ! dis*>ge may "w1 by ! molecul> bomb>dm5t ( ! gas & consequ5t heat+1 ?r\gh z mu* z an in* ( ! be/ solid insulat+ mat]ial1 su* z glass1 h>d rubb]1 porcela91 seal+ wax1 etc42 9 fact1 ?r\gh any kn[n insulat+ sub/ance4 ,! *ief requisite 9 ! insulation ( ! app>atus is1 !re=e1 ! exclusion ( any gase\s matt]4 ,9 g5]al my exp]i5ce t5ds to %[ t bodies :i* possess ! highe/ specific inductive capacity1 su* z glass1 af=d a r inf]ior insulation to o!rs1 :i*1 :ile !y are good insulators1 h a mu* small] specific inductive capacity1 su* z oils1 = in/ance1 ! dielectric losses be+ no d\bt great] 9 ! =m]4 ,! difficulty ( insulat+1 ( c\rse1 only exi/s :5 ! pot5tials are excessively high1 = ) pot5tials su* z a few ?\s& volts !re is no p>ticul> difficulty enc\nt]$ 9 convey+ curr5ts f a ma*9e giv+1 say1 #bj1jjj alt]nations p] second1 to q a di/ance4 ,?is numb] ( alt]nations1 h[ev]1 is by f> too small = _m purposes1 ?\gh q suffici5t = "s practical applications4 ,?is difficulty ( insulat+ is =tunately n a vital drawback2 x affects mo/ly ! size ( ! app>atus1 =1 :5 excessively high pot5tials w\ld be us$1 ! light-giv+ devices w\ld be locat$ n f> f ! app>atus1 & (t5 !y w\ld be q close to x4 ,z ! air-bomb>dm5t ( ! insulat$ wire is dep5d5t on cond5s] action1 ! loss may be r$uc$ to a trifle by us+ excessively ?9 wires heavily insulat$4 ,ano!r difficulty w be enc\nt]$ 9 ! capacity & self-induction necess>ily possess$ by ! coil4 ,if ! coil be l>ge1 t is1 if x conta9 a great l5g? ( wire1 x w be g5]ally unsuit$ = excessively high frequ5cies2 if x be small1 x may be well adapt$ = su* frequ5cies1 b ! pot5tial might !n n be z high z desir$4 ,a good insulator1 & pref]ably "o possess+ a small specific inductive capacity1 w\ld af=d a two-fold advantage4 ,fir/1 x w\ld enable u to con/ruct a v small coil capable ( )/&+ enorm\s diff]5ces ( pot5tial2 & secondly1 su* a small coil1 by reason ( its small] capacity & self-induction1 w\ld be capable ( a quick] & m vigor\s vibration4 ,! problem !n ( con/ruct+ a coil or induction app>atus ( any k9d possess+ ! requisite qualities ,i reg>d z "o ( no small importance1 & x has occupi$ me = a consid]able "t4 ,! inve/igator :o desires to repeat ! exp]im5ts :i* ,i w describe1 ) an alt]nate curr5t ma*9e1 capable ( supply+ curr5ts ( ! desir$ frequ5cy1 & an induction coil1 w d well to take ! prim>y coil out & m\nt ! second>y 9 su* a mann] z to be able to look ?r\gh ! tube ^u :i* ! second>y is w\nd4 ,he w !n be able to obs]ve ! /reams :i* pass f ! prim>y to ! insulat+ tube1 & f _! int5sity he w "k h[ f> he c /ra9 ! coil4 ,)\t ?is precaution he is sure to injure ! insulation4 ,?is arrangem5t p]mits1 h[ev]1 an easy ex*ange ( ! prim>ies1 :i* is desirable 9 ^! exp]im5ts4 ,! selection ( ! type ( ma*9e be/ suit$ = ! purpose mu/ be left to ! judgm5t ( ! exp]im5t]4 ,!re are "h illu/rat$ ?ree di/9ct types ( ma*9es1 :i*1 besides o!rs1 ,i h us$ 9 my exp]im5ts4 ,fig4 #ig repres5ts ! ma*9e us$ 9 my exp]im5ts be=e ?is ,in/itute4 ,! field magnet consi/s ( a r+ ( wr\ght iron ) #chd pole projections4 ,! armature comprises a /eel disc to :i* is fa/5$ a ?91 c>efully weld$ rim ( wr\ght iron4 ,^u ! rim are w\nd sev]al lay]s ( f9e1 well anneal$ iron wire1 :i*1 :5 w\nd1 is pass$ ?r\gh %ellac4 ,! armature wires are w\nd ar\nd brass p9s1 wrapp$ ) silk ?read4 ,! diamet] ( ! armature wire 9 ?is type ( ma*9e %\ld n be m ?an #a_/f ( ! ?ickness ( ! pole projections1 else ! local action w be consid]able4 ,illu/ration3 ,,fig4 #ig4 ,fig4 #ih repres5ts a l>g] ma*9e ( a diff]5t type4 ,! field magnet ( ?is ma*9e consi/s ( two l p>ts :i* ei!r enclose an excit+ coil1 or else are indep5d5tly w\nd4 ,ea* "p has #dhj pole projections1 ! projections ( "o fac+ ^? ( ! o!r4 ,! armature consi/s ( a :eel ( h>d bronze1 c>ry+ ! conductors :i* revolve betwe5 ! projections ( ! field magnet4 ,to w9d ! armature conductors1 ,i h f\nd x mo/ conv5i5t to proce$ 9 ! foll[+ mann]4 ,i con/ruct a r+ ( h>d bronze ( ! requir$ size4 ,?is r+ & ! rim ( ! :eel are provid$ ) ! prop] numb] ( p9s1 & bo? fa/5$ ^u a plate4 ,! armature conductors be+ w\nd1 ! p9s are cut (f & ! ends ( ! conductors fa/5$ by two r+s :i* screw to ! bronze r+ & ! rim ( ! :eel1 respectively4 ,! :ole may !n be tak5 (f & =ms a solid /ructure4 ,! conductors 9 su* a type ( ma*9e %\ld consi/ ( %eet copp]1 ! ?ickness ( :i*1 ( c\rse1 dep5ds on ! ?ickness ( ! pole projections2 or else twi/$ ?9 wires %\ld be employ$4 ,fig4 #ii is a small] ma*9e1 9 _m respects simil> to ! =m]1 only "h ! armature conductors & ! excit+ coil are kept /ation>y1 :ile only a block ( wr\ght iron is revolv$4 ,illu/ration3 ,,fig4 #ih4 ,x w\ld be uselessly l5g!n+ ?is description 7 ,i to dwell m on ! details ( con/ruction ( ^! ma*9es4 ,besides1 !y h be5 describ$ some:at m elaborately 9 ,! ,electrical ,eng9e]1 ( ,m>* #ah1 #ahia4 ,i deem x well1 h[ev]1 to call ! att5tion ( ! inve/igator to two ?+s1 ! importance ( :i*1 ?\gh self evid5t1 he is nev]!less apt to und]e/imate2 namely1 to ! local action 9 ! conductors :i* mu/ be c>efully avoid$1 & to ! cle>ance1 :i* mu/ be small4 ,i may add1 t s9ce x is desirable to use v high p]iph]al spe$s1 ! armature %\ld be ( v l>ge diamet] 9 ord] to avoid impracticable belt spe$s4 ,( ! sev]al types ( ^! ma*9es :i* h be5 con/ruct$ by me1 ,i h f\nd t ! type illu/rat$ 9 ,fig4 #ig caus$ me ! lea/ tr\ble 9 con/ruction1 z well z 9 ma9t5ance1 & on ! :ole1 x has be5 a good exp]im5tal ma*9e4 ,9 op]at+ an induction coil ) v rapidly alt]nat+ curr5ts1 among ! fir/ lum9\s ph5om5a notic$ are naturally ^? pres5t$ by ! high-t5sion dis*>ge4 ,z ! numb] ( alt]nations p] second is increas$1 or z--! numb] be+ high--! curr5t ?r\gh ! prim>y is v>i$1 ! dis*>ge gradually *anges 9 appe>ance4 ,x w\ld be difficult to describe ! m9or *anges :i* occur1 & ! conditions :i* br+ !m ab\t1 b "o may note five di/9ct =ms ( ! dis*>ge4 ,illu/ration3 ,,fig4 #ii4 ,fir/1 "o may obs]ve a weak1 s5sitive dis*>ge 9 ! =m ( a ?91 feeble-color$ ?read4 7,fig4 #ajj;a47 ,x always occurs :51 ! numb] ( alt]nations p] second be+ high1 ! curr5t ?r\gh ! prim>y is v small4 ,9 spite ( ! excessively small curr5t1 ! rate ( *ange is great1 & ! diff]5ce ( pot5tial at ! t]m9als ( ! second>y is !re=e consid]able1 s t ! arc is e/abli%$ at great di/ances2 b ! quantity ( electricity set 9 motion is insignificant1 b>ely suffici5t to ma9ta9 a ?91 ?readlike arc4 ,x is excessively s5sitive & may be made s to su* a degree t ! m]e act ( brea?+ ne> ! coil w affect x1 & unless x is p]fectly well protect$ f curr5ts ( air1 x wriggles ar\nd con/antly4 ,nev]!less1 x is 9 ?is =m excessively p]si/5t1 & :5 ! t]m9als are approa*$ to1 say1 "o-?ird ( ! /rik+ di/ance1 x c be bl[n out only ) difficulty4 ,?is exceptional p]si/5cy1 :5 %ort1 is l>gely due to ! arc be+ excessively ?92 pres5t+1 !re=e1 a v small surface to ! bla/4 ,its great s5sitiv5ess1 :5 v long1 is probably due to ! motion ( ! p>ticles ( du/ susp5d$ 9 ! air4 ,illu/ration3 ,,fig4 #ajj;a4 ,illu/ration3 ,,fig4 #ajj;b4 ,:5 ! curr5t ?r\gh ! prim>y is increas$1 ! dis*>ge gets broad] & /rong]1 & ! effect ( ! capacity ( ! coil becomes visible until1 f9ally1 "u prop] conditions1 a :ite flam+ arc1 ,fig4 #ajj ,b1 (t5 z ?ick z "o's f+]1 & /rik+ across ! :ole coil1 is produc$4 ,x develops rem>kable heat1 & may be fur!r *>act]iz$ by ! abs5ce ( ! high note :i* accompanies ! less p[]ful dis*>ges4 ,to take a %ock f ! coil "u ^! conditions w\ld n be advisable1 al?\gh "u diff]5t conditions1 ! pot5tial be+ mu* high]1 a %ock f ! coil may be tak5 ) impunity4 ,to produce ?is k9d ( dis*>ge ! numb] ( alt]nations p] second mu/ n be too great = ! coil us$2 &1 g5]ally speak+1 c]ta9 relations betwe5 capacity1 self-induction & frequ5cy mu/ be obs]v$4 ,! importance ( ^! elem5ts 9 an alt]nate curr5t circuit is n[ well-kn[n1 & "u ord9>y conditions1 ! g5]al rules are applicable4 ,b 9 an induction coil exceptional conditions prevail4 ,fir/1 ! self-induction is ( little importance be=e ! arc is e/abli%$1 :5 x ass]ts itself1 b p]haps nev] z prom95tly z 9 ord9>y alt]nate curr5t circuits1 because ! capacity is di/ribut$ all along ! coil1 & by reason ( ! fact t ! coil usually dis*>ges ?r\gh v great resi/ances2 h5ce ! curr5ts are exceptionally small4 ,secondly1 ! capacity goes on increas+ cont9ually z ! pot5tial rises1 9 consequ5ce ( absorption :i* takes place to a consid]able ext5t4 ,ow+ to ?is !re exi/s no critical relation%ip betwe5 ^! quantities1 & ord9>y rules w\ld n seem to be applicable4 ,z ! pot5tial is increas$ ei!r 9 consequ5ce ( ! increas$ frequ5cy or ( ! increas$ curr5t ?r\gh ! prim>y1 ! am\nt ( ! en]gy /or$ becomes great] & great]1 & ! capacity ga9s m & m 9 importance4 ,up to a c]ta9 po9t ! capacity is b5eficial1 b aft] t x beg9s to be an enorm\s drawback4 ,x foll[s f ?is t ea* coil gives ! be/ result ) a giv5 frequ5cy & prim>y curr5t4 ,a v l>ge coil1 :5 op]at$ ) curr5ts ( v high frequ5cy1 may n give z mu* z #a_/h in* sp>k4 ,by add+ capacity to ! t]m9als1 ! condition may be improv$1 b :at ! coil really wants is a l[] frequ5cy4 ,:5 ! flam+ dis*>ge occurs1 ! conditions are evid5tly su* t ! greate/ curr5t is made to fl[ ?r\gh ! circuit4 ,^! conditions may be atta9$ by v>y+ ! frequ5cy )9 wide limits1 b ! highe/ frequ5cy at :i* ! flam+ arc c /ill be produc$1 det]m9es1 = a giv5 prim>y curr5t1 ! maximum /rik+ di/ance ( ! coil4 ,9 ! flam+ dis*>ge ! eclat effect ( ! capacity is n p]ceptible2 ! rate at :i* ! en]gy is be+ /or$ !n j equals ! rate at :i* x c be dispos$ ( ?r\gh ! circuit4 ,?is k9d ( dis*>ge is ! sev]e/ te/ = a coil2 ! break1 :5 x occurs1 is ( ! nature ( t 9 an ov]*>g$ ,leyd5 j>4 ,to give a r\gh approximation ,i w\ld /ate t1 ) an ord9>y coil (1 say #aj1jjj ohms resi/ance1 ! mo/ p[]ful arc w\ld be produc$ ) ab\t #ab1jjj alt]nations p] second4 ,:5 ! frequ5cy is increas$ beyond t rate1 ! pot5tial1 ( c\rse1 rises1 b ! /rik+ di/ance may1 nev]!less1 dim9i%1 p>adoxical z x may seem4 ,z ! pot5tial rises ! coil atta9s m & m ! prop]ties ( a /atic ma*9e until1 f9ally1 "o may obs]ve ! beautiful ph5om5on ( ! /ream+ dis*>ge1 ,fig4 #aja1 :i* may be produc$ across ! :ole l5g? ( ! coil4 ,at t /age /reams beg9 to issue freely f all po9ts & projections4 ,^! /reams w also be se5 to pass 9 abundance 9 ! space betwe5 ! prim>y & ! insulat+ tube4 ,:5 ! pot5tial is excessively high !y w always appe>1 ev5 if ! frequ5cy be l[1 & ev5 if ! prim>y be surr\nd$ by z mu* z an in* ( wax1 h>d rubb]1 glass1 or any o!r insulat+ sub/ance4 ,?is limits greatly ! output ( ! coil1 b ,i w lat] %[ h[ ,i h be5 able to ov]come to a consid]able ext5t ?is disadvantage 9 ! ord9>y coil4 ,besides ! pot5tial1 ! int5sity ( ! /reams dep5ds on ! frequ5cy2 b if ! coil be v l>ge !y %[ !mselves1 no matt] h[ l[ ! frequ5cies us$4 ,= in/ance1 9 a v l>ge coil ( a resi/ance ( #fg1jjj ohms1 con/ruct$ by me "s "t ago1 !y appe> ) z l[ z #ajj alt]nations p] second & less1 ! insulation ( ! second>y be+ #c_/d in* ( ebonite4 ,:5 v int5se !y produce a noise simil> to t produc$ by ! *>g+ ( a ,holtz ma*9e1 b mu* m p[]ful1 & !y emit a /rong smell ( ozone4 ,! l[] ! frequ5cy1 ! m apt !y are to sudd5ly injure ! coil4 ,) excessively high frequ5cies !y may pass freely )\t produc+ any o!r effect ?an to heat ! insulation sl[ly & uni=mly4 ,illu/ration3 ,,fig4 #aja4 ,illu/ration3 ,,fig4 #ajb4 ,! exi/5ce ( ^! /reams %[s ! importance ( con/ruct+ an exp5sive coil s z to p]mit ( "o's see+ ?r\gh ! tube surr\nd+ ! prim>y1 & ! latt] %\ld be easily ex*angeable2 or else ! space betwe5 ! prim>y & second>y %\ld be completely fill$ up ) insulat+ mat]ial s z to exclude all air4 ,! non-obs]vance ( ?is simple rule 9 ! con/ruction ( comm]cial coils is responsible = ! de/ruction ( _m an exp5sive coil4 ,at ! /age :5 ! /ream+ dis*>ge occurs1 or ) some:at high] frequ5cies1 "o may1 by approa*+ ! t]m9als q ne>ly1 & regulat+ prop]ly ! effect ( capacity1 produce a v]itable spray ( small silv]-:ite sp>ks1 or a bun* ( excessively ?9 silv]y ?reads 7,fig4 #ajb7 amid/ a p[]ful bru%--ea* sp>k or ?read possibly correspond+ to "o alt]nation4 ,?is1 :5 produc$ "u prop] conditions1 is probably ! mo/ beautiful dis*>ge1 & :5 an air bla/ is direct$ aga9/ x1 x pres5ts a s+ul> appe>ance4 ,! spray ( sp>ks1 :5 receiv$ ?r\gh ! body1 causes "s inconv5i5ce1 :]eas1 :5 ! dis*>ge simply /reams1 no?+ at all is likely to be felt if l>ge conduct+ objects are held 9 ! h&s to protect !m f receiv+ small burns4 ,if ! frequ5cy is /ill m increas$1 !n ! coil refuses to give any sp>k unless at comp>atively small di/ances1 & ! fif? typical =m ( dis*>ge may be obs]v$ 7,fig4 #ajc74 ,! t5d5cy to /ream out & dissipate is !n s great t :5 ! bru% is produc$ at "o t]m9al no sp>k+ occurs1 ev5 if1 z ,i h repeat$ly tri$1 ! h&1 or any conduct+ object1 is held )9 ! /ream2 &1 :at is m s+ul>1 ! lum9\s /ream is n at all easily deflect$ by ! approa* ( a conduct+ body4 ,illu/ration3 ,,fig4 #ajc4 ,illu/ration3 ,,fig4 #ajd4 ,at ?is /age ! /reams seem+ly pass ) ! greate/ fre$om ?r\gh consid]able ?icknesses ( insulators1 & x is p>ticul>ly int]e/+ to /udy _! behavior4 ,= ?is purpose x is conv5i5t to connect to ! t]m9als ( ! coil two metallic sph]es :i* may be plac$ at any desir$ di/ance1 ,fig4 #ajd4 ,sph]es are pref]able to plates1 z ! dis*>ge c be bett] obs]v$4 ,by ins]t+ dielectric bodies betwe5 ! sph]es1 beautiful dis*>ge ph5om5a may be obs]v$4 ,if ! sph]es be q close & a sp>k be play+ betwe5 !m1 by int]pos+ a ?9 plate ( ebonite betwe5 ! sph]es ! sp>k in/antly ceases & ! dis*>ge spreads into an int5sely lum9\s circle sev]al in*es 9 diamet]1 provid$ ! sph]es are suffici5tly l>ge4 ,! passage ( ! /reams heats1 &1 aft] a :ile1 s(t5s1 ! rubb] s mu* t two plates may be made to /ick toge!r 9 ?is mann]4 ,if ! sph]es are s f> ap>t t no sp>k occurs1 ev5 if !y are f> beyond ! /rik+ di/ance1 by ins]t+ a ?ick plate ( glass ! dis*>ge is in/antly induc$ to pass f ! sph]es to ! glass 9 ! =m ( lum9\s /reams4 ,x appe>s almo/ z ?\gh ^! /reams pass ?r\gh ! dielectric4 ,9 reality ?is is n ! case1 z ! /reams are due to ! molecules ( ! air :i* are viol5tly agitat$ 9 ! space betwe5 ! oppositely *>g$ surfaces ( ! sph]es4 ,:5 no dielectric o!r ?an air is pres5t1 ! bomb>dm5t goes on1 b is too weak to be visible2 by ins]t+ a dielectric ! inductive effect is mu* increas$1 & besides1 ! project$ air molecules f9d an ob/acle & ! bomb>dm5t becomes s int5se t ! /reams become lum9\s4 ,if by any me*anical means we c\ld effect su* a viol5t agitation ( ! molecules we c\ld produce ! same ph5om5on4 ,a jet ( air escap+ ?r\gh a small hole "u enorm\s pressure & /rik+ aga9/ an insulat+ sub/ance1 su* z glass1 may be lum9\s 9 ! d>k1 & x might be possible to produce a phosphoresc5ce ( ! glass or o!r insulators 9 ?is mann]4 ,! great] ! specific inductive capacity ( ! int]pos$ dielectric1 ! m p[]ful ! effect produc$4 ,ow+ to ?is1 ! /reams %[ !mselves ) excessively high pot5tials ev5 if ! glass be z mu* z "o & "o-half to two in*es ?ick4 ,b besides ! heat+ due to bomb>dm5t1 "s heat+ goes on und\bt$ly 9 ! dielectric1 be+ app>5tly great] 9 glass ?an 9 ebonite4 ,i attribute ?is to ! great] specific inductive capacity ( ! glass1 9 consequ5ce ( :i*1 ) ! same pot5tial diff]5ce1 a great] am\nt ( en]gy is tak5 up 9 x ?an 9 rubb]4 ,x is l connect+ to a batt]y a copp] & a brass wire ( ! same dim5sions4 ,! copp] wire1 ?\gh a m p]fect conductor1 w\ld heat m by reason ( its tak+ m curr5t4 ,?us :at is o!rwise consid]$ a virtue ( ! glass is "h a defect4 ,glass usually gives way mu* quick] ?an ebonite2 :5 x is heat$ to a c]ta9 degree1 ! dis*>ge sudd5ly breaks ?r\gh at "o po9t1 assum+ !n ! ord9>y =m ( an arc4 ,! heat+ effect produc$ by molecul> bomb>dm5t ( ! dielectric w\ld1 ( c\rse1 dim9i% z ! pressure ( ! air is increas$1 & at enorm\s pressure x w\ld be negligible1 unless ! frequ5cy w\ld increase correspond+ly4 ,x w be (t5 obs]v$ 9 ^! exp]im5ts t :5 ! sph]es are beyond ! /rik+ di/ance1 ! approa* ( a glass plate1 = in/ance1 may induce ! sp>k to jump betwe5 ! sph]es4 ,?is occurs :5 ! capacity ( ! sph]es is some:at bel[ ! critical value :i* gives ! greate/ diff]5ce ( pot5tial at ! t]m9als ( ! coil4 ,by approa*+ a dielectric1 ! specific inductive capacity ( ! space betwe5 ! sph]es is increas$1 produc+ ! same effect z if ! capacity ( ! sph]es 7 increas$4 ,! pot5tial at ! t]m9als may !n rise s high t ! air space is crack$4 ,! exp]im5t is be/ p]=m$ ) d5se glass or mica4 ,ano!r int]e/+ obs]vation is t a plate ( insulat+ mat]ial1 :5 ! dis*>ge is pass+ ?r\gh x1 is /rongly attract$ by ei!r ( ! sph]es1 t is by ! ne>] "o1 ?is be+ obvi\sly due to ! small] me*anical effect ( ! bomb>dm5t on t side1 & p]haps also to ! great] electrification4 ,f ! behavior ( ! dielectrics 9 ^! exp]im5ts1 we may conclude t ! be/ insulator = ^! rapidly alt]nat+ curr5ts w\ld be ! "o possess+ ! smalle/ specific inductive capacity & at ! same "t "o capable ( )/&+ ! greate/ diff]5ces ( pot5tial2 & ?us two diametrically opposite ways ( secur+ ! requir$ insulation are indicat$1 namely1 to use ei!r a p]fect vacuum or a gas "u great pressure2 b ! =m] w\ld be pref]able4 ,un=tunately nei!r ( ^! two ways is easily c>ri$ out 9 practice4 ,x is especially int]e/+ to note ! behavior ( an excessively high vacuum 9 ^! exp]im5ts4 ,if a te/ tube1 provid$ ) ext]nal electrodes & exhau/$ to ! highe/ possible degree1 be connect$ to ! t]m9als ( ! coil1 ,fig4 #aje1 ! electrodes ( ! tube are in/antly br\ght to a high temp]ature & ! glass at ea* end ( ! tube is r5d]$ int5sely phosphoresc5t1 b ! middle appe>s comp>atively d>k1 & = a :ile rema9s cool4 ,:5 ! frequ5cy is s high t ! dis*>ge %[n 9 ,fig4 #ajc is obs]v$1 consid]able dissipation no d\bt occurs 9 ! coil4 ,nev]!less ! coil may be work$ = a long "t1 z ! heat+ is gradual4 ,9 spite ( ! fact t ! diff]5ce ( pot5tial may be enorm\s1 little is felt :5 ! dis*>ge is pass$ ?r\gh ! body1 provid$ ! h&s are arm$4 ,?is is to "s ext5t due to ! high] frequ5cy1 b pr9cipally to ! fact t less en]gy is available ext]nally1 :5 ! diff]5ce ( pot5tial rea*es an enorm\s value1 ow+ to ! circum/ance t1 ) ! rise ( pot5tial1 ! en]gy absorb$ 9 ! coil increases z ! squ>e ( ! pot5tial4 ,up to a c]ta9 po9t ! en]gy available ext]nally increases ) ! rise ( pot5tial1 !n x beg9s to fall (f rapidly4 ,?us1 ) ! ord9>y high t5sion induction coil1 ! curi\s p>adox exi/s1 t1 :ile ) a giv5 curr5t ?r\gh ! prim>y ! %ock might be fatal1 ) _m times t curr5t x might be p]fectly h>mless1 ev5 if ! frequ5cy be ! same4 ,) high frequ5cies & excessively high pot5tials :5 ! t]m9als are n connect$ to bodies ( "s size1 practically all ! en]gy suppli$ to ! prim>y is tak5 up by ! coil4 ,!re is no break+ ?r\gh1 no local injury1 b all ! mat]ial1 insulat+ & conduct+1 is uni=mly heat$4 ,illu/ration3 ,,fig4 #aje4 ,illu/ration3 ,,fig4 #ajf4 ,to avoid misund]/&+ 9 reg>d to ! physiological effect ( alt]nat+ curr5ts ( v high frequ5cy1 ,i ?9k x necess>y to /ate t1 :ile x is an und5iable fact t !y are incomp>ably less dang]\s ?an curr5ts ( l[ frequ5cies1 x %\ld n be ?\ght t !y are altoge!r h>mless4 ,:at has j be5 said ref]s only to curr5ts f an ord9>y high t5sion induction coil1 :i* curr5ts are necess>ily v small2 if receiv$ directly f a ma*9e or f a second>y ( l[ resi/ance1 !y produce m or less p[]ful effects1 & may cause s]i\s injury1 especially :5 us$ 9 conjunction ) cond5s]s4 ,! /ream+ dis*>ge ( a high t5sion induction coil diff]s 9 _m respects f t ( a p[]ful /atic ma*9e4 ,9 color x has nei!r ! violet ( ! positive1 nor ! brightness ( ! negative1 /atic dis*>ge1 b lies some:]e betwe51 be+1 ( c\rse1 alt]natively positive & negative4 ,b s9ce ! /ream+ is m p[]ful :5 ! po9t or t]m9al is electrifi$ positively1 ?an :5 electrifi$ negatively1 x foll[s t ! po9t ( ! bru% is m l ! positive1 & ! root m l ! negative1 /atic dis*>ge4 ,9 ! d>k1 :5 ! bru% is v p[]ful1 ! root may appe> almo/ :ite4 ,! w9d produc$ by ! escap+ /reams1 ?\gh x may be v /rong--(t5 inde$ to su* a degree t x may be felt q a di/ance f ! coil--is1 nev]!less1 consid]+ ! quantity ( ! dis*>ge1 small] ?an t produc$ by ! positive bru% ( a /atic ma*9e1 & x affects ! flame mu* less p[]fully4 ,f ! nature ( ! ph5om5on we c conclude t ! high] ! frequ5cy1 ! small] mu/1 ( c\rse1 be ! w9d produc$ by ! /reams1 & ) suffici5tly high frequ5cies no w9d at all w\ld be produc$ at ! ord9>y atmosph]ic pressures4 ,) frequ5cies obta9able by means ( a ma*9e1 ! me*anical effect is suffici5tly great to revolve1 ) consid]able spe$1 l>ge p9-:eels1 :i* 9 ! d>k pres5t a beautiful appe>ance ow+ to ! abundance ( ! /reams 7,fig4 #ajf74 ,illu/ration3 ,,fig4 #ajg4 ,illu/ration3 ,,fig4 #ajh4 ,9 g5]al1 mo/ ( ! exp]im5ts usually p]=m$ ) a /atic ma*9e c be p]=m$ ) an induction coil :5 op]at$ ) v rapidly alt]nat+ curr5ts4 ,! effects produc$1 h[ev]1 are mu* m /rik+1 be+ ( incomp>ably great] p[]4 ,:5 a small l5g? ( ord9>y cotton cov]$ wire1 ,fig4 #ajg1 is atta*$ to "o t]m9al ( ! coil1 ! /reams issu+ f all po9ts ( ! wire may be s int5se z to produce a consid]able light effect4 ,:5 ! pot5tials & frequ5cies are v high1 a wire insulat$ ) gutta p]*a or rubb] & atta*$ to "o ( ! t]m9als1 appe>s to be cov]$ ) a lum9\s film4 ,a v ?9 b>e wire :5 atta*$ to a t]m9al emits p[]ful /reams & vibrates cont9ually to & fro or sp9s 9 a circle1 produc+ a s+ul> effect 7,fig4 #ajh74 ,"s ( ^! exp]im5ts h be5 describ$ by me 9 ,! ,electrical ,_w1 ( ,febru>y #ba1 #ahia4 ,ano!r peculi>ity ( ! rapidly alt]nat+ dis*>ge ( ! induction coil is its radically diff]5t behavior ) respect to po9ts & r\nd$ surfaces4 ,if a ?ick wire1 provid$ ) a ball at "o end & ) a po9t at ! o!r1 be atta*$ to ! positive t]m9al ( a /atic ma*9e1 practically all ! *>ge w be lo/ ?r\gh ! po9t1 on acc\nt ( ! enorm\sly great] t5sion1 dep5d5t on ! radius ( curvature4 ,b if su* a wire is atta*$ to "o ( ! t]m9als ( ! induction coil1 x w be obs]v$ t ) v high frequ5cies /reams issue f ! ball almo/ z copi\sly z f ! po9t 7,fig4 #aji74 ,x is h>dly conceivable t we c\ld produce su* a condition to an equal degree 9 a /atic ma*9e1 = ! simple reason1 t ! t5sion increases z ! squ>e ( ! d5sity1 :i* 9 turn is proportional to ! radius ( curvature2 h5ce1 ) a /eady pot5tial an enorm\s *>ge w\ld be requir$ to make /reams issue f a poli%$ ball :ile x is connect$ ) a po9t4 ,b ) an induction coil ! dis*>ge ( :i* alt]nates ) great rapidity x is diff]5t4 ,"h we h to deal ) two di/9ct t5d5cies4 ,fir/1 !re is ! t5d5cy to escape :i* exi/s 9 a condition ( re/1 & :i* dep5ds on ! radius ( curvature2 second1 !re is ! t5d5cy to dissipate into ! surr\nd+ air by cond5s] action1 :i* dep5ds on ! surface4 ,:5 "o ( ^! t5d5cies is a maximum1 ! o!r is at a m9imum4 ,at ! po9t ! lum9\s /ream is pr9cipally due to ! air molecules com+ bodily 9 contact ) ! po9t2 !y are attract$ & repell$1 *>g$ & dis*>g$1 &1 _! atomic *>ges be+ ?us di/urb$1 vibrate & emit light waves4 ,at ! ball1 on ! contr>y1 !re is no d\bt t ! effect is to a great ext5t produc$ inductively1 ! air molecules n necess>ily com+ 9 contact ) ! ball1 ?\gh !y und\bt$ly d s4 ,to conv9ce ourselves ( ?is we only ne$ to exalt ! cond5s] action1 = in/ance1 by envelop+ ! ball1 at "s di/ance1 by a bett] conductor ?an ! surr\nd+ m$ium1 ! conductor be+1 ( c\rse1 insulat$2 or else by surr\nd+ x ) a bett] dielectric & approa*+ an insulat$ conductor2 9 bo? cases ! /reams w break =? m copi\sly4 ,also1 ! l>g] ! ball ) a giv5 frequ5cy1 or ! high] ! frequ5cy1 ! m w ! ball h ! advantage ov] ! po9t4 ,b1 s9ce a c]ta9 int5sity ( action is requir$ to r5d] ! /reams visible1 x is obvi\s t 9 ! exp]im5t describ$ ! ball %\ld n be tak5 too l>ge4 ,9 consequ5ce ( ?is two-fold t5d5cy1 x is possible to produce by means ( po9ts1 effects id5tical to ^? produc$ by capacity4 ,?us1 = in/ance1 by atta*+ to "o t]m9al ( ! coil a small l5g? ( soil$ wire1 pres5t+ _m po9ts & (f]+ great facility to escape1 ! pot5tial ( ! coil may be rais$ to ! same value z by atta*+ to ! t]m9al a poli%$ ball ( a surface _m times great] ?an t ( ! wire4 ,illu/ration3 ,,fig4 #aji4 ,illu/ration3 ,,fig4 #aaj4 ,an int]e/+ exp]im5t1 %[+ ! effect ( ! po9ts1 may be p]=m$ 9 ! foll[+ mann]3 ,atta* to "o ( ! t]m9als ( ! coil a cotton cov]$ wire ab\t two feet 9 l5g?1 & adju/ ! conditions s t /reams issue f ! wire4 ,9 ?is exp]im5t ! prim>y coil %\ld be pref]ably plac$ s t x ext5ds only ab\t half way into ! second>y coil4 ,n[ t\* ! free t]m9al ( ! second>y ) a conduct+ object held 9 ! h&1 or else connect x to an insulat$ body ( "s size4 ,9 ?is mann] ! pot5tial on ! wire may be enorm\sly rais$4 ,! effect ( ?is w be ei!r to increase1 or to dim9i%1 ! /reams4 ,if !y increase1 ! wire is too %ort2 if !y dim9i%1 x is too long4 ,by adju/+ ! l5g? ( ! wire1 a po9t is f\nd :]e ! t\*+ ( ! o!r t]m9al does n at all affect ! /reams4 ,9 ?is case ! rise ( pot5tial is exactly c\nt]act$ by ! drop ?r\gh ! coil4 ,x w be obs]v$ t small l5g?s ( wire produce consid]able diff]5ce 9 ! magnitude & lum9osity ( ! /reams4 ,! prim>y coil is plac$ sidewise = two reasons3 ,fir/1 to increase ! pot5tial at ! wire2 &1 second1 to increase ! drop ?r\gh ! coil4 ,! s5sitiv5ess is ?us augm5t$4 ,!re is /ill ano!r & f> m /rik+ peculi>ity ( ! bru% dis*>ge produc$ by v rapidly alt]nat+ curr5ts4 ,to obs]ve ?is x is be/ to replace ! usual t]m9als ( ! coil by two metal columns insulat$ ) a good ?ickness ( ebonite4 ,x is also well to close all fissures & cracks ) wax s t ! bru%es _c =m any:]e except at ! tops ( ! columns4 ,if ! conditions are c>efully adju/$--:i*1 ( c\rse1 mu/ be left to ! skill ( ! exp]im5t]--s t ! pot5tial rises to an enorm\s value1 "o may produce two p[]ful bru%es sev]al in*es long1 ne>ly :ite at _! roots1 :i* 9 ! d>k be> a /rik+ resemblance to two flames ( a gas escap+ "u pressure 7,fig4 #aaj74 ,b !y d n only resemble1 !y are v]itable flames1 = !y are hot4 ,c]ta9ly !y are n z hot z a gas burn]1 b !y w\ld be s if ! frequ5cy & ! pot5tial w\ld be suffici5tly high4 ,produc$ )1 say1 tw5ty ?\s& alt]nations p] second1 ! heat is easily p]ceptible ev5 if ! pot5tial is n excessively high4 ,! heat develop$ is1 ( c\rse1 due to ! impact ( ! air molecules aga9/ ! t]m9als & aga9/ ea* o!r4 ,z1 at ! ord9>y pressures1 ! mean free pa? is excessively small1 x is possible t 9 spite ( ! enorm\s initial spe$ imp>t$ to ea* molecule ^u com+ 9 contact ) ! t]m9al1 its progress--by collision ) o!r molecules--is ret>d$ to su* an ext5t1 t x does n get away f> f ! t]m9al1 b may /rike ! same _m times 9 succession4 ,! high] ! frequ5cy1 ! less ! molecule is able to get away1 & ?is ! m s1 z = a giv5 effect ! pot5tial requir$ is small]2 & a frequ5cy is conceivable--p]haps ev5 obta9able--at :i* practically ! same molecules w\ld /rike ! t]m9al4 ,"u su* conditions ! ex*ange ( ! molecules w\ld be v sl[1 & ! heat produc$ at1 & v ne>1 ! t]m9al w\ld be excessive4 ,b if ! frequ5cy w\ld g on increas+ con/antly1 ! heat produc$ w\ld beg9 to dim9i% = obvi\s reasons4 ,9 ! positive bru% ( a /atic ma*9e ! ex*ange ( ! molecules is v rapid1 ! /ream is con/antly ( "o direction1 & !re are few] collisions2 h5ce ! heat+ effect mu/ be v small4 ,any?+ t impairs ! facility ( ex*ange t5ds to increase ! local heat produc$4 ,?us1 if a bulb be held ov] ! t]m9al ( ! coil s z to enclose ! bru%1 ! air conta9$ 9 ! bulb is v quickly br\ght to a high temp]ature4 ,if a glass tube be held ov] ! bru% s z to all[ ! draught to c>ry ! bru% upw>ds1 scor*+ hot air escapes at ! top ( ! tube4 ,any?+ held )9 ! bru% is1 ( c\rse1 rapidly heat$1 & ! possibility ( us+ su* heat+ effects = "s purpose or o!r sugge/s itself4 ,:5 contemplat+ ?is s+ul> ph5om5on ( ! hot bru%1 we _c help be+ conv9c$ t a simil> process mu/ take place 9 ! ord9>y flame1 & x seems /range t aft] all ^! c5turies pa/ ( famili>ity ) ! flame1 n[1 9 ?is era ( electric light+ & heat+1 we are f9ally l$ to recognize1 t s9ce "t immemorial we h1 aft] all1 always _h electric light & heat at our disposal4 ,x is also ( no little int]e/ to contemplate1 t we h a possible way ( produc+--by o!r ?an *emical means--a v]itable flame1 :i* w\ld give light & heat )\t any mat]ial be+ consum$1 )\t any *emical process tak+ place1 & to accompli% ?is1 we only ne$ to p]fect me?ods ( produc+ enorm\s frequ5cies & pot5tials4 ,i h no d\bt t if ! pot5tial c\ld be made to alt]nate ) suffici5t rapidity & p[]1 ! bru% =m$ at ! end ( a wire w\ld lose its electrical *>act]i/ics & w\ld become flamelike4 ,! flame mu/ be due to electro/atic molecul> action4 ,?is ph5om5on n[ expla9s 9 a mann] :i* c h>dly be d\bt$ ! frequ5t accid5ts occurr+ 9 /orms4 ,x is well kn[n t objects are (t5 set on fire )\t ! lightn+ /rik+ !m4 ,we %all pres5tly see h[ ?is c happ54 ,on a nail 9 a ro(1 = in/ance1 or on a projection ( any k9d1 m or less conduct+1 or r5d]$ s by dampness1 a p[]ful bru% may appe>4 ,if ! lightn+ /rikes some:]e 9 ! neighborhood ! enorm\s pot5tial may be made to alt]nate or fluctuate p]haps _m million times a second4 ,! air molecules are viol5tly attract$ & repell$1 & by _! impact produce su* a p[]ful heat+ effect t a fire is />t$4 ,x is conceivable t a %ip at sea may1 9 ?is mann]1 cat* fire at _m po9ts at once4 ,:5 we consid]1 t ev5 ) ! comp>atively l[ frequ5cies obta9$ f a dynamo ma*9e1 & ) pot5tials ( no m ?an "o or two hundr$ ?\s& volts1 ! heat+ effects are consid]able1 we may imag9e h[ mu* m p[]ful !y mu/ be ) frequ5cies & pot5tials _m times great]2 & ! above explanation seems1 to say ! lea/1 v probable4 ,simil> explanations may h be5 sugge/$1 b ,i am n aw>e t1 up to ! pres5t1 ! heat+ effects ( a bru% produc$ by a rapidly alt]nat+ pot5tial h be5 exp]im5tally demon/rat$1 at lea/ n to su* a rem>kable degree4 ,illu/ration3 ,,fig4 #aaa4 ,by prev5t+ completely ! ex*ange ( ! air molecules1 ! local heat+ effect may be s exalt$ z to br+ a body to inc&esc5ce4 ,?us1 = in/ance1 if a small button1 or pref]ably a v ?9 wire or filam5t be enclos$ 9 an unexhau/$ globe & connect$ ) ! t]m9al ( ! coil1 x may be r5d]$ inc&esc5t4 ,! ph5om5on is made mu* m int]e/+ by ! rapid sp9n+ r\nd 9 a circle ( ! top ( ! filam5t1 ?us pres5t+ ! appe>ance ( a lum9\s funnel1 ,fig4 #aaa1 :i* wid5s :5 ! pot5tial is increas$4 ,:5 ! pot5tial is small ! end ( ! filam5t may p]=m irregul> motions1 sudd5ly *ang+ f "o to ! o!r1 or x may describe an ellipse2 b :5 ! pot5tial is v high x always sp9s 9 a circle2 & s does g5]ally a ?9 /raight wire atta*$ freely to ! t]m9al ( ! coil4 ,^! motions are1 ( c\rse1 due to ! impact ( ! molecules1 & ! irregul>ity 9 ! di/ribution ( ! pot5tial1 ow+ to ! r\ghness & dissymmetry ( ! wire or filam5t4 ,) a p]fectly symmetrical & poli%$ wire su* motions w\ld probably n occur4 ,t ! motion is n likely to be due to o!rs causes is evid5t f ! fact t x is n ( a def9ite direction1 & t 9 a v highly exhau/$ globe x ceases altoge!r4 ,! possibility ( br++ a body to inc&esc5ce 9 an exhau/$ globe1 or ev5 :5 n at all enclos$1 w\ld seem to af=d a possible way ( obta9+ light effects1 :i*1 9 p]fect+ me?ods ( produc+ rapidly alt]nat+ pot5tials1 might be r5d]$ available = useful purposes4 ,illu/ration3 ,,fig4 #aab;a4 ,9 employ+ a comm]cial coil1 ! production ( v p[]ful bru% effects is att5d$ ) consid]able difficulties1 = :5 ^! high frequ5cies & enorm\s pot5tials are us$1 ! be/ insulation is apt to give way4 ,usually ! coil is insulat$ well en\gh to /& ! /ra9 f convolution to convolution1 s9ce two d\ble silk cov]$ p>aff9$ wires w )/& a pressure ( sev]al ?\s& volts2 ! difficulty lies pr9cipally 9 prev5t+ ! break+ ?r\gh f ! second>y to ! prim>y1 :i* is greatly facilitat$ by ! /reams issu+ f ! latt]4 ,9 ! coil1 ( c\rse1 ! /ra9 is greate/ f section to section1 b usually 9 a l>g] coil !re are s _m sections t ! dang] ( a sudd5 giv+ way is n v great4 ,no difficulty w g5]ally be enc\nt]$ 9 t direction1 & besides1 ! liability ( injur+ ! coil int]nally is v mu* r$uc$ by ! fact t ! effect mo/ likely to be produc$ is simply a gradual heat+1 :i*1 :5 f> en\gh advanc$1 c\ld n fail to be obs]v$4 ,! pr9cipal necessity is !n to prev5t ! /reams betwe5 ! prim>y & ! tube1 n only on acc\nt ( ! heat+ & possible injury1 b also because ! /reams may dim9i% v consid]ably ! pot5tial diff]5ce available at ! t]m9als4 ,a few h9ts z to h[ ?is may be accompli%$ w probably be f\nd useful 9 mo/ ( ^! exp]im5ts ) ! ord9>y induction coil4 ,illu/ration3 ,,fig4 #aab;b4 ,"o ( ! ways is to w9d a %ort prim>y1 ,fig4 #aab;a1 s t ! diff]5ce ( pot5tial is n at t l5g? great en\gh to cause ! break+ =? ( ! /reams ?r\gh ! insulat+ tube4 ,! l5g? ( ! prim>y %\ld be det]m9$ by exp]im5t4 ,bo? ! ends ( ! coil %\ld be br\ght out on "o end ?r\gh a plug ( insulat+ mat]ial fitt+ 9 ! tube z illu/rat$4 ,9 su* a disposition "o t]m9al ( ! second>y is atta*$ to a body1 ! surface ( :i* is det]m9$ ) ! greate/ c>e s z to produce ! greate/ rise 9 ! pot5tial4 ,at ! o!r t]m9al a p[]ful bru% appe>s1 :i* may be exp]im5t$ ^u4 ,! above plan necessitates ! employm5t ( a prim>y ( comp>atively small size1 & x is apt to heat :5 p[]ful effects are desirable = a c]ta9 l5g? ( "t4 ,9 su* a case x is bett] to employ a l>g] coil1 ,fig4 #aab;b1 & introduce x f "o side ( ! tube1 until ! /reams beg9 to appe>4 ,9 ?is case ! ne>e/ t]m9al ( ! second>y may be connect$ to ! prim>y or to ! gr\nd1 :i* is practically ! same ?+1 if ! prim>y is connect$ directly to ! ma*9e4 ,9 ! case ( gr\nd connections x is well to det]m9e exp]im5tally ! frequ5cy :i* is be/ suit$ "u ! conditions ( ! te/4 ,ano!r way ( obviat+ ! /reams1 m or less1 is to make ! prim>y 9 sections & supply x f sep>ate1 well insulat$ s\rces4 ,9 _m ( ^! exp]im5ts1 :5 p[]ful effects are want$ = a %ort "t1 x is advantage\s to use iron cores ) ! prim>ies4 ,9 su* case a v l>ge prim>y coil may be w\nd & plac$ side by side ) ! second>y1 &1 ! ne>e/ t]m9al ( ! latt] be+ connect$ to ! prim>y1 a lam9at$ iron core is introduc$ ?r\gh ! prim>y into ! second>y z f> z ! /reams w p]mit4 ,"u ^! conditions an excessively p[]ful bru%1 sev]al in*es long1 :i* may be appropriately call$ ,/4 ,elmo's hot fire1 may be caus$ to appe> at ! o!r t]m9al ( ! second>y1 produc+ /rik+ effects4 ,x is a mo/ p[]ful ozoniz]1 s p[]ful inde$1 t only a few m9utes are suffici5t to fill ! :ole room ) ! smell ( ozone1 & x und\bt$ly possesses ! quality ( excit+ *emical aff9ities4 ,= ! production ( ozone1 alt]nat+ curr5ts ( v high frequ5cy are em95tly suit$1 n only on acc\nt ( ! advantages !y (f] 9 ! way ( conv]sion b also because ( ! fact1 t ! ozoniz+ action ( a dis*>ge is dep5d5t on ! frequ5cy z well z on ! pot5tial1 ?is be+ und\bt$ly confirm$ by obs]vation4 ,9 ^! exp]im5ts if an iron core is us$ x %\ld be c>efully wat*$1 z x is apt to get excessively hot 9 an incr$ibly %ort "t4 ,to give an idea ( ! rapidity ( ! heat+1 ,i w /ate1 t by pass+ a p[]ful curr5t ?r\gh a coil ) _m turns1 ! ins]t+ )9 ! same ( a ?9 iron wire = no m ?an "o second's "t is suffici5t to heat ! wire to some?+ l #ajj deg4 ,c4 ,b ?is rapid heat+ ne$ n disc\rage u 9 ! use ( iron cores 9 connection ) rapidly alt]nat+ curr5ts4 ,i h = a long "t be5 conv9c$ t 9 ! indu/rial di/ribution by means ( trans=m]s1 "s su* plan z ! foll[+ might be practicable4 ,we may use a comp>atively small iron core1 subdivid$1 or p]haps n ev5 subdivid$4 ,we may surr\nd ?is core ) a consid]able ?ickness ( mat]ial :i* is fire-pro( & conducts ! heat poorly1 & on top ( t we may place ! prim>y & second>y w9d+s4 ,by us+ ei!r high] frequ5cies or great] magnetiz+ =ces1 we may by hy/]esis & eddy curr5ts heat ! iron core s f> z to br+ x ne>ly to its maximum p]meability1 :i*1 z ,hopk9son has %[n1 may be z mu* z sixte5 times great] ?an t at ord9>y temp]atures4 ,if ! iron core 7 p]fectly enclos$1 x w\ld n be det]iorat$ by ! heat1 &1 if ! enclosure ( fire-pro( mat]ial w\ld be suffici5tly ?ick1 only a limit$ am\nt ( en]gy c\ld be radiat$ 9 spite ( ! high temp]ature4 ,trans=m]s h be5 con/ruct$ by me on t plan1 b = lack ( "t1 no ?or\gh te/s h z yet be5 made4 ,ano!r way ( adapt+ ! iron core to rapid alt]nations1 or1 g5]ally speak+1 r$uc+ ! frictional losses1 is to produce by cont9u\s magnetization a fl[ ( some?+ l sev5 ?\s& or eight ?\s& l9es p] squ>e c5timetre ?r\gh ! core1 & !n "w ) weak magnetiz+ =ces & pref]ably high frequ5cies ar\nd ! po9t ( greate/ p]meability4 ,a high] effici5cy ( conv]sion & great] output are obta9able 9 ?is mann]4 ,i h also employ$ ?is pr9ciple 9 connection ) ma*9es 9 :i* !re is no rev]sal ( pol>ity4 ,9 ^! types ( ma*9es1 z long z !re are only few pole projections1 !re is no great ga91 z ! maxima & m9ima ( magnetization are f> f ! po9t ( maximum p]meability2 b :5 ! numb] ( ! pole projections is v great1 ! requir$ rate ( *ange may be obta9$1 )\t ! magnetization v>y+ s f> z to dep>t greatly f ! po9t ( maximum p]meability1 & ! ga9 is consid]able4 ,! above describ$ arrangem5ts ref] only to ! use ( comm]cial coils z ord9>ily con/ruct$4 ,if x is desir$ to con/ruct a coil = ! express purpose ( p]=m+ ) x su* exp]im5ts z ,i h describ$1 or1 g5]ally1 r5d]+ x capable ( )/&+ ! greate/ possible diff]5ce ( pot5tial1 !n a con/ruction z indicat$ 9 ,fig4 #aac w be f\nd ( advantage4 ,! coil 9 ?is case is =m$ ( two indep5d5t p>ts :i* are w\nd oppositely1 ! connection betwe5 bo? be+ made ne> ! prim>y4 ,! pot5tial 9 ! middle be+ z]o1 !re is n mu* t5d5cy to jump to ! prim>y & n mu* insulation is requir$4 ,9 "s cases ! middle po9t may1 h[ev]1 be connect$ to ! prim>y or to ! gr\nd4 ,9 su* a coil ! places ( greate/ diff]5ce ( pot5tial are f> ap>t & ! coil is capable ( )/&+ an enorm\s /ra94 ,! two p>ts may be movable s z to all[ a slight adju/m5t ( ! capacity effect4 ,z to ! mann] ( insulat+ ! coil1 x w be f\nd conv5i5t to proce$ 9 ! foll[+ way3 ,fir/1 ! wire %\ld be boil$ 9 p>aff9e until all ! air is out2 !n ! coil is w\nd by runn+ ! wire ?r\gh melt$ p>aff9e1 m]ely = ! purpose ( fix+ ! wire4 ,! coil is !n tak5 (f f ! spool1 imm]s$ 9 a cyl9drical vessel fill$ ) pure melt$ wax & boil$ = a long "t until ! bubbles cease to appe>4 ,! :ole is !n left to cool d[n ?or\ghly1 & !n ! mass is tak5 out ( ! vessel & turn$ up 9 a la!4 ,a coil made 9 ?is mann] & ) c>e is capable ( )/&+ enorm\s pot5tial diff]5ces4 ,illu/ration3 ,,fig4 #aac4 ,x may be f\nd conv5i5t to imm]se ! coil 9 p>aff9e oil or "s o!r k9d ( oil2 x is a mo/ effective way ( insulat+1 pr9cipally on acc\nt ( ! p]fect exclusion ( air1 b x may be f\nd t1 aft] all1 a vessel fill$ ) oil is n a v conv5i5t ?+ to h&le 9 a laboratory4 ,if an ord9>y coil c be dism\nt$1 ! prim>y may be tak5 out ( ! tube & ! latt] plugg$ up at "o end1 fill$ ) oil1 & ! prim>y re9s]t$4 ,?is af=ds an excell5t insulation & prev5ts ! =mation ( ! /reams4 ,( all ! exp]im5ts :i* may be p]=m$ ) rapidly alt]nat+ curr5ts ! mo/ int]e/+ are ^? :i* conc]n ! production ( a practical illum9ant4 ,x _c be d5i$ t ! pres5t me?ods1 ?\gh !y 7 brilliant advances1 are v wa/eful4 ,"s bett] me?ods mu/ be inv5t$1 "s m p]fect app>atus devis$4 ,mod]n rese>* has op5$ new possibilities = ! production ( an effici5t s\rce ( light1 & ! att5tion ( all has be5 turn$ 9 ! direction indicat$ by able pione]s4 ,_m h be5 c>ri$ away by ! en?usiasm & passion to discov]1 b 9 _! zeal to rea* results1 "s h be5 misl$4 ,/>t+ ) ! idea ( produc+ electro-magnetic waves1 !y turn$ _! att5tion1 p]haps1 too mu* to ! /udy ( electro-magnetic effects1 & neglect$ ! /udy ( electro/atic ph5om5a4 ,naturally1 ne>ly e inve/igator avail$ himself ( an app>atus simil> to t us$ 9 e>li] exp]im5ts4 ,b 9 ^? =ms ( app>atus1 :ile ! electro-magnetic inductive effects are enorm\s1 ! electro/atic effects are excessively small4 ,9 ! ,h]tz exp]im5ts1 = in/ance1 a high t5sion induction coil is %ort circuit$ by an arc1 ! resi/ance ( :i* is v small1 ! small]1 ! m capacity is atta*$ to ! t]m9als2 & ! diff]5ce ( pot5tial at ^! is enorm\sly dim9i%$4 ,on ! o!r h&1 :5 ! dis*>ge is n pass+ betwe5 ! t]m9als1 ! /atic effects may be consid]able1 b only qualitatively s1 n quantitatively1 s9ce _! rise & fall is v sudd51 & s9ce _! frequ5cy is small4 ,9 nei!r case1 !re=e1 are p[]ful electro/atic effects p]ceivable4 ,simil> conditions exi/ :51 z 9 "s int]e/+ exp]im5ts ( ,dr4 ,lodge1 ,leyd5 j>s are dis*>g$ disruptively4 ,x has be5 ?\ght--& ,i believe ass]t$--t 9 su* cases mo/ ( ! en]gy is radiat$ into space4 ,9 ! light ( ! exp]im5ts :i* ,i h describ$ above1 x w n[ n be ?\ght s4 ,i feel safe 9 ass]t+ t 9 su* cases mo/ ( ! en]gy is p>tly tak5 up & conv]t$ into heat 9 ! arc ( ! dis*>ge & 9 ! conduct+ & insulat+ mat]ial ( ! j>1 "s en]gy be+1 ( c\rse1 giv5 (f by electrification ( ! air2 b ! am\nt ( ! directly radiat$ en]gy is v small4 ,:5 a high t5sion induction coil1 op]at$ by curr5ts alt]nat+ only #bj1jjj times a second1 has its t]m9als clos$ ?r\gh ev5 a v small j>1 practically all ! en]gy passes ?r\gh ! dielectric ( ! j>1 :i* is heat$1 & ! electro/atic effects manife/ !mselves outw>dly only to a v weak degree4 ,n[ ! ext]nal circuit ( a ,leyd5 j>1 t is1 ! arc & ! connections ( ! coat+s1 may be look$ ^u z a circuit g5]at+ alt]nat+ curr5ts ( excessively high frequ5cy & fairly high pot5tial1 :i* is clos$ ?r\gh ! coat+s & ! dielectric betwe5 !m1 & f ! above x is evid5t t ! ext]nal electro/atic effects mu/ be v small1 ev5 if a recoil circuit be us$4 ,^! conditions make x appe> t ) ! app>atus usually at h&1 ! obs]vation ( p[]ful electro/atic effects 0 impossible1 & :at exp]i5ce has be5 ga9$ 9 t direction is only due to ! great ability ( ! inve/igators4 ,b p[]ful electro/atic effects are a s9e qua non ( light production on ! l9es indicat$ by !ory4 ,electro-magnetic effects are prim>ily unavailable1 = ! reason t to produce ! requir$ effects we w\ld h to pass curr5t impulses ?r\gh a conductor1 :i*1 long be=e ! requir$ frequ5cy ( ! impulses c\ld be rea*$1 w\ld cease to transmit !m4 ,on ! o!r h&1 electro-magnetic waves _m times long] ?an ^? ( light1 & producible by sudd5 dis*>ge ( a cond5s]1 c\ld n be utiliz$1 x w\ld seem1 except we avail ourselves ( _! effect ^u conductors z 9 ! pres5t me?ods1 :i* are wa/eful4 ,we c\ld n affect by means ( su* waves ! /atic molecul> or atomic *>ges ( a gas1 cause !m to vibrate & to emit light4 ,long transv]se waves _c1 app>5tly1 produce su* effects1 s9ce excessively small electro-magnetic di/urbances may pass readily ?r\gh miles ( air4 ,su* d>k waves1 unless !y are ( ! l5g? ( true light waves1 _c1 x w\ld seem1 excite lum9\s radiation 9 a ,geissl] tube1 & ! lum9\s effects1 :i* are producible by induction 9 a tube devoid ( electrodes1 ,i am incl9$ to consid] z be+ ( an electro/atic nature4 ,to produce su* lum9\s effects1 /raight electro/atic ?ru/s are requir$2 ^!1 :atev] be _! frequ5cy1 may di/urb ! molecul> *>ges & produce light4 ,s9ce curr5t impulses ( ! requir$ frequ5cy _c pass ?r\gh a conductor ( measurable dim5sions1 we mu/ "w ) a gas1 & !n ! production ( p[]ful electro/atic effects becomes an imp]ative necessity4 ,x has occurr$ to me1 h[ev]1 t electro/atic effects are 9 _m ways available = ! production ( light4 ,= in/ance1 we may place a body ( "s refractory mat]ial 9 a clos$1 & pref]ably m or less exhau/$1 globe1 connect x to a s\rce ( high1 rapidly alt]nat+ pot5tial1 caus+ ! molecules ( ! gas to /rike x _m times a second at enorm\s spe$s1 & 9 ?is mann]1 ) trillions ( invisible hamm]s1 p\nd x until x gets inc&esc5t2 or we may place a body 9 a v highly exhau/$ globe1 9 a non-/rik+ vacuum1 &1 by employ+ v high frequ5cies & pot5tials1 transf] suffici5t en]gy f x to o!r bodies 9 ! vic9ity1 or 9 g5]al to ! surr\nd+s1 to ma9ta9 x at any degree ( inc&esc5ce2 or we may1 by means ( su* rapidly alt]nat+ high pot5tials1 di/urb ! e!r c>ri$ by ! molecules ( a gas or _! /atic *>ges1 caus+ !m to vibrate & to emit light4 ,b1 electro/atic effects be+ dep5d5t ^u ! pot5tial & frequ5cy1 to produce ! mo/ p[]ful action x is desirable to increase bo? z f> z practicable4 ,x may be possible to obta9 q fair results by keep+ ei!r ( ^! factors small1 provid$ ! o!r is suffici5tly great2 b we are limit$ 9 bo? directions4 ,my exp]i5ce demon/rates t we _c g bel[ a c]ta9 frequ5cy1 =1 fir/1 ! pot5tial !n becomes s great t x is dang]\s2 &1 secondly1 ! light production is less effici5t4 ,i h f\nd t1 by us+ ! ord9>y l[ frequ5cies1 ! physiological effect ( ! curr5t requir$ to ma9ta9 at a c]ta9 degree ( brightness a tube f\r feet long1 provid$ at ! ends ) outside & inside cond5s] coat+s1 is s p[]ful t1 ,i ?9k1 x might produce s]i\s injury to ^? n accu/om$ to su* %ocks2 :]eas1 ) tw5ty ?\s& alt]nations p] second1 ! tube may be ma9ta9$ at ! same degree ( brightness )\t any effect be+ felt4 ,?is is due pr9cipally to ! fact t a mu* small] pot5tial is requir$ to produce ! same light effect1 & also to ! high] effici5cy 9 ! light production4 ,x is evid5t t ! effici5cy 9 su* cases is ! great]1 ! high] ! frequ5cy1 = ! quick] ! process ( *>g+ & dis*>g+ ! molecules1 ! less en]gy w be lo/ 9 ! =m ( d>k radiation4 ,b1 un=tunately1 we _c g beyond a c]ta9 frequ5cy on acc\nt ( ! difficulty ( produc+ & convey+ ! effects4 ,i h /at$ above t a body inclos$ 9 an unexhau/$ bulb may be int5sely heat$ by simply connect+ x ) a s\rce ( rapidly alt]nat+ pot5tial4 ,! heat+ 9 su* a case is1 9 all probability1 due mo/ly to ! bomb>dm5t ( ! molecules ( ! gas conta9$ 9 ! bulb4 ,:5 ! bulb is exhau/$1 ! heat+ ( ! body is mu* m rapid1 & !re is no difficulty :atev] 9 br++ a wire or filam5t to any degree ( inc&esc5ce by simply connect+ x to "o t]m9al ( a coil ( ! prop] dim5sions4 ,?us1 if ! well-kn[n app>atus ( ,pr(4 ,crookes1 consi/+ ( a b5t plat9um wire ) vanes m\nt$ ov] x 7,fig4 #aad71 be connect$ to "o t]m9al ( ! coil--ei!r "o or bo? ends ( ! plat9um wire be+ connect$--! wire is r5d]$ almo/ in/antly inc&esc5t1 & ! mica vanes are rotat$ z ?\gh a curr5t f a batt]y 7 us$4 ,a ?9 c>bon filam5t1 or1 pref]ably1 a button ( "s refractory mat]ial 7,fig4 #aae71 ev5 if x be a comp>atively poor conductor1 inclos$ 9 an exhau/$ globe1 may be r5d]$ highly inc&esc5t2 & 9 ?is mann] a simple lamp capable ( giv+ any desir$ c&le p[] is provid$4 ,! success ( lamps ( ?is k9d w\ld dep5d l>gely on ! selection ( ! light-giv+ bodies conta9$ )9 ! bulb4 ,s9ce1 "u ! conditions describ$1 refractory bodies--:i* are v poor conductors & capable ( )/&+ = a long "t excessively high degrees ( temp]ature--may be us$1 su* illum9at+ devices may be r5d]$ successful4 ,illu/ration3 ,,fig4 #aad4 ,illu/ration3 ,,fig4 #aae4 ,x might be ?\ght at fir/ t if ! bulb1 conta9+ ! filam5t or button ( refractory mat]ial1 be p]fectly well exhau/$--t is1 z f> z x c be done by ! use ( ! be/ app>atus--! heat+ w\ld be mu* less int5se1 & t 9 a p]fect vacuum x c\ld n occur at all4 ,?is is n confirm$ by my exp]i5ce2 q ! contr>y1 ! bett] ! vacuum ! m easily ! bodies are br\ght to inc&esc5ce4 ,?is result is int]e/+ = _m reasons4 ,at ! outset ( ?is "w ! idea pres5t$ itself to me1 :e!r two bodies ( refractory mat]ial enclos$ 9 a bulb exhau/$ to su* a degree t ! dis*>ge ( a l>ge induction coil1 op]at$ 9 ! usual mann]1 _c pass ?r\gh1 c\ld be r5d]$ inc&esc5t by m]e cond5s] action4 ,obvi\sly1 to rea* ?is result enorm\s pot5tial diff]5ces & v high frequ5cies are requir$1 z is evid5t f a simple calculation4 ,b su* a lamp w\ld possess a va/ advantage ov] an ord9>y inc&esc5t lamp 9 reg>d to effici5cy4 ,x is well-kn[n t ! effici5cy ( a lamp is to "s ext5t a function ( ! degree ( inc&esc5ce1 & t1 c\ld we b "w a filam5t at _m times high] degrees ( inc&esc5ce1 ! effici5cy w\ld be mu* great]4 ,9 an ord9>y lamp ?is is impracticable on acc\nt ( ! de/ruction ( ! filam5t1 & x has be5 det]m9$ by exp]i5ce h[ f> x is advisable to pu% ! inc&esc5ce4 ,x is impossible to tell h[ mu* high] effici5cy c\ld be obta9$ if ! filam5t c\ld )/& indef9itely1 z ! inve/igation to ?is end obvi\sly _c be c>ri$ beyond a c]ta9 /age2 b !re are reasons = believ+ t x w\ld be v consid]ably high]4 ,an improvem5t might be made 9 ! ord9>y lamp by employ+ a %ort & ?ick c>bon2 b !n ! lead+-9 wires w\ld h to be ?ick1 &1 besides1 !re are _m o!r consid]ations :i* r5d] su* a modification entirely impracticable4 ,b 9 a lamp z above describ$1 ! lead+ 9 wires may be v small1 ! inc&esc5t refractory mat]ial may be 9 ! %ape ( blocks (f]+ a v small radiat+ surface1 s t less en]gy w\ld be requir$ to keep !m at ! desir$ inc&esc5ce2 & 9 addition to ?is1 ! refractory mat]ial ne$ n be c>bon1 b may be manufactur$ f mixtures ( oxides1 = in/ance1 ) c>bon or o!r mat]ial1 or may be select$ f bodies :i* are practically non-conductors1 & capable ( )/&+ enorm\s degrees ( temp]ature4 ,all ?is w\ld po9t to ! possibility ( obta9+ a mu* high] effici5cy ) su* a lamp ?an is obta9able 9 ord9>y lamps4 ,9 my exp]i5ce x has be5 demon/rat$ t ! blocks are br\ght to high degrees ( inc&esc5ce ) mu* l[] pot5tials ?an ^? det]m9$ by calculation1 & ! blocks may be set at great] di/ances f ea* o!r4 ,we may freely assume1 & x is probable1 t ! molecul> bomb>dm5t is an important elem5t 9 ! heat+1 ev5 if ! globe be exhau/$ ) ! utmo/ c>e1 z ,i h done2 = al?\gh ! numb] ( ! molecules is1 comp>atively speak+1 insignificant1 yet on acc\nt ( ! mean free pa? be+ v great1 !re are few] collisions1 & ! molecules may rea* mu* high] spe$s1 s t ! heat+ effect due to ?is cause may be consid]able1 z 9 ! ,crookes exp]im5ts ) radiant matt]4 ,b x is likewise possible t we h to deal "h ) an increas$ facility ( los+ ! *>ge 9 v high vacuum1 :5 ! pot5tial is rapidly alt]nat+1 9 :i* case mo/ ( ! heat+ w\ld be directly due to ! surg+ ( ! *>ges 9 ! heat$ bodies4 ,or else ! obs]v$ fact may be l>gely attributable to ! effect ( ! po9ts :i* ,i h m5tion$ above1 9 consequ5ce ( :i* ! blocks or filam5ts conta9$ 9 ! vacuum are equival5t to cond5s]s ( _m times great] surface ?an t calculat$ f _! geometrical dim5sions4 ,sci5tific m5 /ill diff] 9 op9ion z to :e!r a *>ge %\ld1 or %\ld n1 be lo/ 9 a p]fect vacuum1 or 9 o!r words1 :e!r e!r is1 or is n1 a conductor4 ,if ! =m] 7 ! case1 !n a ?9 filam5t enclos$ 9 a p]fectly exhau/$ globe1 & connect$ to a s\rce ( enorm\s1 /eady pot5tial1 w\ld be br\ght to inc&esc5ce4 ,illu/ration3 ,,fig4 #aaf4 ,illu/ration3 ,,fig4 #aag4 ,v>i\s =ms ( lamps on ! above describ$ pr9ciple1 ) ! refractory bodies 9 ! =m ( filam5ts1 ,fig4 #aaf1 or blocks1 ,fig4 #aag1 h be5 con/ruct$ & op]at$ by me1 & inve/igations are be+ c>ri$ on 9 ?is l9e4 ,!re is no difficulty 9 rea*+ su* high degrees ( inc&esc5ce t ord9>y c>bon is to all appe>ance melt$ & volatiliz$4 ,if ! vacuum c\ld be made absolutely p]fect1 su* a lamp1 al?\gh inop]ative ) app>atus ord9>ily us$1 w\ld1 if op]at$ ) curr5ts ( ! requir$ "*1 af=d an illum9ant :i* w\ld nev] be de/roy$1 & :i* w\ld be f> m effici5t ?an an ord9>y inc&esc5t lamp4 ,?is p]fection c1 ( c\rse1 nev] be rea*$1 & a v sl[ de/ruction & gradual dim9ution 9 size always occurs1 z 9 inc&esc5t filam5ts2 b !re is no possibility ( a sudd5 & premature disabl+ :i* occurs 9 ! latt] by ! break+ ( ! filam5t1 especially :5 ! inc&esc5t bodies are 9 ! %ape ( blocks4 ,) ^! rapidly alt]nat+ pot5tials !re is1 h[ev]1 no necessity ( enclos+ two blocks 9 a globe1 b a s+le block1 z 9 ,fig4 #aae1 or filam5t1 ,fig4 #aah1 may be us$4 ,! pot5tial 9 ?is case mu/ ( c\rse be high]1 b is easily obta9able1 & besides x is n necess>ily dang]\s4 ,illu/ration3 ,,fig4 #aah4 ,! facility ) :i* ! button or filam5t 9 su* a lamp is br\ght to inc&esc5ce1 o!r ?+s be+ equal1 dep5ds on ! size ( ! globe4 ,if a p]fect vacuum c\ld be obta9$1 ! size ( ! globe w\ld n be ( importance1 = !n ! heat+ w\ld be :olly due to ! surg+ ( ! *>ges1 & all ! en]gy w\ld be giv5 (f to ! surr\nd+s by radiation4 ,b ?is c nev] occur 9 practice4 ,!re is always "s gas left 9 ! globe1 & al?\gh ! exhau/ion may be c>ri$ to ! highe/ degree1 /ill ! space inside ( ! bulb mu/ be consid]$ z conduct+ :5 su* high pot5tials are us$1 & ,i assume t1 9 e/imat+ ! en]gy t may be giv5 (f f ! filam5t to ! surr\nd+s1 we may consid] ! inside surface ( ! bulb z "o coat+ ( a cond5s]1 ! air & o!r objects surr\nd+ ! bulb =m+ ! o!r coat+4 ,:5 ! alt]nations are v l[ !re is no d\bt t a consid]able portion ( ! en]gy is giv5 (f by ! electrification ( ! surr\nd+ air4 ,9 ord] to /udy ?is subject bett]1 ,i c>ri$ on "s exp]im5ts ) excessively high pot5tials & l[ frequ5cies4 ,i !n obs]v$ t :5 ! h& is approa*$ to ! bulb1--! filam5t be+ connect$ ) "o t]m9al ( ! coil1--a p[]ful vibration is felt1 be+ due to ! attraction & repulsion ( ! molecules ( ! air :i* are electrifi$ by induction ?r\gh ! glass4 ,9 "s cases :5 ! action is v int5se ,i h be5 able to he> a s\nd1 :i* mu/ be due to ! same cause4 ,illu/ration3 ,,fig4 #aai4 ,illu/ration3 ,,fig4 #abj4 ,:5 ! alt]nations are l[1 "o is apt to get an excessively p[]ful %ock f ! bulb4 ,9 g5]al1 :5 "o atta*es bulbs or objects ( "s size to ! t]m9als ( ! coil1 "o %\ld look out = ! rise ( pot5tial1 = x may happ5 t by m]ely connect+ a bulb or plate to ! t]m9al1 ! pot5tial may rise to _m times its orig9al value4 ,:5 lamps are atta*$ to ! t]m9als1 z illu/rat$ 9 ,fig4 #aai1 !n ! capacity ( ! bulbs %\ld be su* z to give ! maximum rise ( pot5tial "u ! exi/+ conditions4 ,9 ?is mann] "o may obta9 ! requir$ pot5tial ) few] turns ( wire4 ,! life ( su* lamps z describ$ above dep5ds1 ( c\rse1 l>gely on ! degree ( exhau/ion1 b to "s ext5t also on ! %ape ( ! block ( refractory mat]ial4 ,!oretically x w\ld seem t a small sph]e ( c>bon enclos$ 9 a sph]e ( glass w\ld n suff] det]ioration f molecul> bomb>dm5t1 =1 ! matt] 9 ! globe be+ radiant1 ! molecules w\ld move 9 /raight l9es1 & w\ld seldom /rike ! sph]e obliquely4 ,an int]e/+ ?\ght 9 connection ) su* a lamp is1 t 9 x electricity & electrical en]gy app>5tly mu/ move 9 ! same l9es4 ,illu/ration3 ,,fig4 #aba;a4 ,illu/ration3 ,,fig4 #aba;b4 ,! use ( alt]nat+ curr5ts ( v high frequ5cy makes x possible to transf]1 by electro/atic or electromagnetic induction ?r\gh ! glass ( a lamp1 suffici5t en]gy to keep a filam5t at inc&esc5ce & s d away ) ! lead+-9 wires4 ,su* lamps h be5 propos$1 b = want ( prop] app>atus !y h n be5 successfully op]at$4 ,_m =ms ( lamps on ?is pr9ciple ) cont9u\s & brok5 filam5ts h be5 con/ruct$ by me & exp]im5t$ ^u4 ,:5 us+ a second>y enclos$ )9 ! lamp1 a cond5s] is advantage\sly comb9$ ) ! second>y4 ,:5 ! transf]5ce is effect$ by electro/atic induction1 ! pot5tials us$ are1 ( c\rse1 v high ) frequ5cies obta9able f a ma*9e4 ,= in/ance1 ) a cond5s] surface ( =ty squ>e c5timetres1 :i* is n impracticably l>ge1 & ) glass ( good quality #a mm4 ?ick1 us+ curr5ts alt]nat+ tw5ty ?\s& times a second1 ! pot5tial requir$ is approximately #i1jjj volts4 ,?is may seem l>ge1 b s9ce ea* lamp may be includ$ 9 ! second>y ( a trans=m] ( v small dim5sions1 x w\ld n be inconv5i5t1 &1 moreov]1 x w\ld n produce fatal injury4 ,! trans=m]s w\ld all be pref]ably 9 s]ies4 ,! regulation w\ld (f] no difficulties1 z ) curr5ts ( su* frequ5cies x is v easy to ma9ta9 a con/ant curr5t4 ,9 ! accompany+ engrav+s "s ( ! types ( lamps ( ?is k9d are %[n4 ,fig4 #abj is su* a lamp ) a brok5 filam5t1 & ,figs4 #aba ,a & #aba ,b "o ) a s+le outside & inside coat+ & a s+le filam5t4 ,i h also made lamps ) two outside & inside coat+s & a cont9u\s loop connect+ ! latt]4 ,su* lamps h be5 op]at$ by me ) curr5t impulses ( ! enorm\s frequ5cies obta9able by ! disruptive dis*>ge ( cond5s]s4 ,! disruptive dis*>ge ( a cond5s] is especially suit$ = op]at+ su* lamps--) no outw>d electrical connections--by means ( electromagnetic induction1 ! electromagnetic inductive effects be+ excessively high2 & ,i h be5 able to produce ! desir$ inc&esc5ce ) only a few %ort turns ( wire4 ,inc&esc5ce may also be produc$ 9 ?is mann] 9 a simple clos$ filam5t4 ,leav+ n[ out ( consid]ation ! practicability ( su* lamps1 ,i w\ld only say t !y possess a beautiful & desirable feature1 namely1 t !y c be r5d]$1 at w1 m or less brilliant simply by alt]+ ! relative position ( ! outside & inside cond5s] coat+s1 or induc+ & induc$ circuits4 ,:5 a lamp is light$ by connect+ x to "o t]m9al only ( ! s\rce1 ?is may be facilitat$ by provid+ ! globe ) an outside cond5s] coat+1 :i* s]ves at ! same "t z a reflector1 & connect+ ?is to an insulat$ body ( "s size4 ,lamps ( ?is k9d are illu/rat$ 9 ,fig4 #abb & ,fig4 #abc4 ,fig4 #abd %[s ! plan ( connection4 ,! brilliancy ( ! lamp may1 9 ?is case1 be regulat$ )9 wide limits by v>y+ ! size ( ! insulat$ metal plate to :i* ! coat+ is connect$4 ,x is likewise practicable to light ) "o lead+ wire lamps su* z illu/rat$ 9 ,fig4 #aaf & ,fig4 #aag1 by connect+ "o t]m9al ( ! lamp to "o t]m9al ( ! s\rce1 & ! o!r to an insulat$ body ( ! requir$ size4 ,9 all cases ! insulat$ body s]ves to give (f ! en]gy into ! surr\nd+ space1 & is equival5t to a return wire4 ,obvi\sly1 9 ! two la/-nam$ cases1 in/ead ( connect+ ! wires to an insulat$ body1 connections may be made to ! gr\nd4 ,! exp]im5ts :i* w prove mo/ sugge/ive & ( mo/ int]e/ to ! inve/igator are probably ^? p]=m$ ) exhau/$ tubes4 ,z might be anticipat$1 a s\rce ( su* rapidly alt]nat+ pot5tials is capable ( excit+ ! tubes at a consid]able di/ance1 & ! light effects produc$ are rem>kable4 ,illu/ration3 ,,fig4 #abb4 ,illu/ration3 ,,fig4 #abc4 ,dur+ my inve/igations 9 ?is l9e ,i endeavor$ to excite tubes1 devoid ( any electrodes1 by electromagnetic induction1 mak+ ! tube ! second>y ( ! induction device1 & pass+ ?r\gh ! prim>y ! dis*>ges ( a ,leyd5 j>4 ,^! tubes 7 made ( _m %apes1 & ,i 0 able to obta9 lum9\s effects :i* ,i !n ?\ght 7 due :olly to electromagnetic induction4 ,b on c>efully inve/igat+ ! ph5om5a ,i f\nd t ! effects produc$ 7 m ( an electro/atic nature4 ,x may be attribut$ to ?is circum/ance t ?is mode ( excit+ tubes is v wa/eful1 namely1 ! prim>y circuit be+ clos$1 ! pot5tial1 & consequ5tly ! electro/atic inductive effect1 is mu* dim9i%$4 ,:5 an induction coil1 op]at$ z above describ$1 is us$1 !re is no d\bt t ! tubes are excit$ by electro/atic induction1 & t electromagnetic induction has little1 if any?+1 to d ) ! ph5om5a4 ,illu/ration3 ,,fig4 #abd4 ,?is is evid5t f _m exp]im5ts4 ,= in/ance1 if a tube be tak5 9 "o h&1 ! obs]v] be+ ne> ! coil1 x is brilliantly light$ & rema9s s no matt] 9 :at position x is held relatively to ! obs]v]'s body4 ,7 ! action electromagnetic1 ! tube c\ld n be light$ :5 ! obs]v]'s body is int]pos$ betwe5 x & ! coil1 or at lea/ its lum9osity %\ld be consid]ably dim9i%$4 ,:5 ! tube is held exactly ov] ! c5tre ( ! coil--! latt] be+ w\nd 9 sections & ! prim>y plac$ symmetrically to ! second>y--x may rema9 completely d>k1 :]eas x is r5d]$ int5sely lum9\s by mov+ x slightly to ! "r or left f ! c5tre ( ! coil4 ,x does n light because 9 ! middle bo? halves ( ! coil neutralize ea* o!r1 & ! electric pot5tial is z]o4 ,if ! action 7 electromagnetic1 ! tube %\ld light be/ 9 ! plane ?r\gh ! c5tre ( ! coil1 s9ce ! electromagnetic effect !re %\ld be a maximum4 ,:5 an arc is e/abli%$ betwe5 ! t]m9als1 ! tubes & lamps 9 ! vic9ity ( ! coil g out1 b light up aga9 :5 ! arc is brok51 on acc\nt ( ! rise ( pot5tial4 ,yet ! electromagnetic effect %\ld be practically ! same 9 bo? cases4 ,by plac+ a tube at "s di/ance f ! coil1 & ne>] to "o t]m9al--pref]ably at a po9t on ! axis ( ! coil--"o may light x by t\*+ ! remote t]m9al ) an insulat$ body ( "s size or ) ! h&1 !reby rais+ ! pot5tial at t t]m9al ne>] to ! tube4 ,if ! tube is %ift$ ne>] to ! coil s t x is light$ by ! action ( ! ne>] t]m9al1 x may be made to g out by hold+1 on an insulat$ support1 ! end ( a wire connect$ to ! remote t]m9al1 9 ! vic9ity ( ! ne>] t]m9al1 by ?is means c\nt]act+ ! action ( ! latt] ^u ! tube4 ,^! effects are evid5tly electro/atic4 ,likewise1 :5 a tube is plac$ at a consid]able di/ance f ! coil1 ! obs]v] may1 /&+ ^u an insulat$ support betwe5 coil & tube1 light ! latt] by approa*+ ! h& to x2 or he may ev5 r5d] x lum9\s by simply /epp+ betwe5 x & ! coil4 ,?is w\ld be impossible ) electro-magnetic induction1 = ! body ( ! obs]v] w\ld act z a scre54 ,:5 ! coil is en]giz$ by excessively weak curr5ts1 ! exp]im5t] may1 by t\*+ "o t]m9al ( ! coil ) ! tube1 ext+ui% ! latt]1 & may aga9 light x by br++ x out ( contact ) ! t]m9al & all[+ a small arc to =m4 ,?is is cle>ly due to ! respective l[]+ & rais+ ( ! pot5tial at t t]m9al4 ,9 ! above exp]im5t1 :5 ! tube is light$ ?r\gh a small arc1 x may g out :5 ! arc is brok51 because ! electro/atic inductive effect alone is too weak1 ?\gh ! pot5tial may be mu* high]2 b :5 ! arc is e/abli%$1 ! electrification ( ! end ( ! tube is mu* great]1 & x consequ5tly lights4 ,if a tube is light$ by hold+ x ne> to ! coil1 & 9 ! h& :i* is remote1 by grasp+ ! tube any:]e ) ! o!r h&1 ! "p betwe5 ! h&s is r5d]$ d>k1 & ! s+ul> effect ( wip+ out ! light ( ! tube may be produc$ by pass+ ! h& quickly along ! tube & at ! same "t )draw+ x g5tly f ! coil1 judg+ prop]ly ! di/ance s t ! tube rema9s d>k aft]w>ds4 ,if ! prim>y coil is plac$ sidewise1 z 9 ,fig4 #aab ,b = in/ance1 & an exhau/$ tube be introduc$ f ! o!r side 9 ! holl[ space1 ! tube is light$ mo/ int5sely because ( ! increas$ cond5s] action1 & 9 ?is position ! /riae are mo/ %>ply def9$4 ,9 all ^! exp]im5ts describ$1 & 9 _m o!rs1 ! action is cle>ly electro/atic4 ,! effects ( scre5+ also indicate ! electro/atic nature ( ! ph5om5a & %[ some?+ ( ! nature ( electrification ?r\gh ! air4 ,= in/ance1 if a tube is plac$ 9 ! direction ( ! axis ( ! coil1 & an insulat$ metal plate be int]pos$1 ! tube w g5]ally increase 9 brilliancy1 or if x be too f> f ! coil to light1 x may ev5 be r5d]$ lum9\s by int]pos+ an insulat$ metal plate4 ,! magnitude ( ! effects dep5ds to "s ext5t on ! size ( ! plate4 ,b if ! metal plate be connect$ by a wire to ! gr\nd1 its int]position w always make ! tube g out ev5 if x be v ne> ! coil4 ,9 g5]al1 ! int]position ( a body betwe5 ! coil & tube1 increases or dim9i%es ! brilliancy ( ! tube1 or its facility to light up1 accord+ to :e!r x increases or dim9i%es ! electrification4 ,:5 exp]im5t+ ) an insulat$ plate1 ! plate %\ld n be tak5 too l>ge1 else x w g5]ally produce a weak5+ effect by reason ( its great facility = giv+ (f en]gy to ! surr\nd+s4 ,if a tube be light$ at "s di/ance f ! coil1 & a plate ( h>d rubb] or o!r insulat+ sub/ance be int]pos$1 ! tube may be made to g out4 ,! int]position ( ! dielectric 9 ?is case only slightly increases ! inductive effect1 b dim9i%es consid]ably ! electrification ?r\gh ! air4 ,9 all cases1 !n1 :5 we excite lum9osity 9 exhau/$ tubes by means ( su* a coil1 ! effect is due to ! rapidly alt]nat+ electro/atic pot5tial2 &1 fur!rmore1 x mu/ be attribut$ to ! h>monic alt]nation produc$ directly by ! ma*9e1 & n to any sup]impos$ vibration :i* might be ?\ght to exi/4 ,su* sup]impos$ vibrations are impossible :5 we "w ) an alt]nate curr5t ma*9e4 ,if a spr+ be gradually tight5$ & releas$1 x does n p]=m indep5d5t vibrations2 = ?is a sudd5 release is necess>y4 ,s ) ! alt]nate curr5ts f a dynamo ma*9e2 ! m$ium is h>monically /ra9$ & releas$1 ?is giv+ rise to only "o k9d ( waves2 a sudd5 contact or break1 or a sudd5 giv+ way ( ! dielectric1 z 9 ! disruptive dis*>ge ( a ,leyd5 j>1 are ess5tial = ! production ( sup]impos$ waves4 ,9 all ! la/ describ$ exp]im5ts1 tubes devoid ( any electrodes may be us$1 & !re is no difficulty 9 produc+ by _! means suffici5t light to read by4 ,! light effect is1 h[ev]1 consid]ably increas$ by ! use ( phosphoresc5t bodies su* z yttria1 uranium glass1 etc4 ,a difficulty w be f\nd :5 ! phosphoresc5t mat]ial is us$1 = ) ^! p[]ful effects1 x is c>ri$ gradually away1 & x is pref]able to use mat]ial 9 ! =m ( a solid4 ,in/ead ( dep5d+ on induction at a di/ance to light ! tube1 ! same may be provid$ ) an ext]nal--&1 if desir$1 also ) an int]nal--cond5s] coat+1 & x may !n be susp5d$ any:]e 9 ! room f a conductor connect$ to "o t]m9al ( ! coil1 & 9 ?is mann] a s(t illum9ation may be provid$4 ,illu/ration3 ,,fig4 #abe4 ,! ideal way ( light+ a hall or room w\ld1 h[ev]1 be to produce su* a condition 9 x t an illum9at+ device c\ld be mov$ & put any:]e1 & t x is light$1 no matt] :]e x is put & )\t be+ electrically connect$ to any?+4 ,i h be5 able to produce su* a condition by creat+ 9 ! room a p[]ful1 rapidly alt]nat+ electro/atic field4 ,= ?is purpose ,i susp5d a %eet ( metal a di/ance f ! ceil+ on insulat+ cords & connect x to "o t]m9al ( ! induction coil1 ! o!r t]m9al be+ pref]ably connect$ to ! gr\nd4 ,or else ,i susp5d two %eets z illu/rat$ 9 ,fig4 #abe1 ea* %eet be+ connect$ ) "o ( ! t]m9als ( ! coil1 & _! size be+ c>efully det]m9$4 ,an exhau/$ tube may !n be c>ri$ 9 ! h& any:]e betwe5 ! %eets or plac$ any:]e1 ev5 a c]ta9 di/ance beyond !m2 x rema9s always lum9\s4 ,9 su* an electro/atic field int]e/+ ph5om5a may be obs]v$1 especially if ! alt]nations are kept l[ & ! pot5tials excessively high4 ,9 addition to ! lum9\s ph5om5a m5tion$1 "o may obs]ve t any insulat$ conductor gives sp>ks :5 ! h& or ano!r object is approa*$ to x1 & ! sp>ks may (t5 be p[]ful4 ,:5 a l>ge conduct+ object is fa/5$ on an insulat+ support1 & ! h& approa*$ to x1 a vibration1 due to ! ry?mical motion ( ! air molecules is felt1 & lum9\s /reams may be p]ceiv$ :5 ! h& is held ne> a po9t$ projection4 ,:5 a telephone receiv] is made to t\* ) "o or bo? ( its t]m9als an insulat$ conductor ( "s size1 ! telephone emits a l\d s\nd2 x also emits a s\nd :5 a l5g? ( wire is atta*$ to "o or bo? t]m9als1 & ) v p[]ful fields a s\nd may be p]ceiv$ ev5 )\t any wire4 ,h[ f> ?is pr9ciple is capable ( practical application1 ! future w tell4 ,x might be ?\ght t electro/atic effects are unsuit$ = su* action at a di/ance4 ,electromagnetic inductive effects1 if available = ! production ( light1 might be ?\ght bett] suit$4 ,x is true ! electro/atic effects dim9i% ne>ly ) ! cube ( ! di/ance f ! coil1 :]eas ! electromagnetic inductive effects dim9i% simply ) ! di/ance4 ,b :5 we e/abli% an electro/atic field ( =ce1 ! condition is v diff]5t1 = !n1 in/ead ( ! diff]5tial effect ( bo? ! t]m9als1 we get _! conjo9t effect4 ,besides1 ,i w\ld call att5tion to ! effect1 t 9 an alt]nat+ electro/atic field1 a conductor1 su* z an exhau/$ tube1 = in/ance1 t5ds to take up mo/ ( ! en]gy1 :]eas 9 an electromagnetic alt]nat+ field ! conductor t5ds to take up ! lea/ en]gy1 ! waves be+ reflect$ ) b little loss4 ,?is is "o reason :y x is difficult to excite an exhau/$ tube1 at a di/ance1 by electromagnetic induction4 ,i h w\nd coils ( v l>ge diamet] & ( _m turns ( wire1 & connect$ a ,geissl] tube to ! ends ( ! coil ) ! object ( excit+ ! tube at a di/ance2 b ev5 ) ! p[]ful inductive effects producible by ,leyd5 j> dis*>ges1 ! tube c\ld n be excit$ unless at a v small di/ance1 al?\gh "s judgm5t 0 us$ z to ! dim5sions ( ! coil4 ,i h also f\nd t ev5 ! mo/ p[]ful ,leyd5 j> dis*>ges are capable ( excit+ only feeble lum9\s effects 9 a clos$ exhau/$ tube1 & ev5 ^! effects ^u ?or\gh exam9ation ,i h be5 =c$ to consid] ( an electro/atic nature4 ,h[ !n c we hope to produce ! requir$ effects at a di/ance by means ( electromagnetic action1 :5 ev5 9 ! close/ proximity to ! s\rce ( di/urbance1 "u ! mo/ advantage\s conditions1 we c excite b fa9t lum9osity8 ,x is true t :5 act+ at a di/ance we h ! resonance to help u out4 ,we c connect an exhau/$ tube1 or :atev] ! illum9at+ device may be1 ) an insulat$ sy/em ( ! prop] capacity1 & s x may be possible to increase ! effect qualitatively1 & only qualitatively1 = we w\ld n get m en]gy ?r\gh ! device4 ,s we may1 by resonance effect1 obta9 ! requir$ electromotive =ce 9 an exhau/$ tube1 & excite fa9t lum9\s effects1 b we _c get en\gh en]gy to r5d] ! light practically available1 & a simple calculation1 bas$ on exp]im5tal results1 %[s t ev5 if all ! en]gy :i* a tube w\ld receive at a c]ta9 di/ance f ! s\rce %\ld be :olly conv]t$ into light1 x w\ld h>dly satisfy ! practical requirem5ts4 ,h5ce ! necessity ( direct+1 by means ( a conduct+ circuit1 ! en]gy to ! place ( trans=mation4 ,b 9 s do+ we _c v s5sibly dep>t f pres5t me?ods1 & all we c\ld d w\ld be to improve ! app>atus4 ,f ^! consid]ations x w\ld seem t if ?is ideal way ( light+ is to be r5d]$ practicable x w be only by ! use ( electro/atic effects4 ,9 su* a case ! mo/ p[]ful electro/atic inductive effects are ne$$2 ! app>atus employ$ mu/1 !re=e1 be capable ( produc+ high electro/atic pot5tials *ang+ 9 value ) extreme rapidity4 ,high frequ5cies are especially want$1 = practical consid]ations make x desirable to keep d[n ! pot5tial4 ,by ! employm5t ( ma*9es1 or1 g5]ally speak+1 ( any me*anical app>atus1 b l[ frequ5cies c be rea*$2 rec\rse mu/1 !re=e1 be _h to "s o!r means4 ,! dis*>ge ( a cond5s] af=ds u a means ( obta9+ frequ5cies by f> high] ?an are obta9able me*anically1 & ,i h accord+ly employ$ cond5s]s 9 ! exp]im5ts to ! above end4 ,:5 ! t]m9als ( a high t5sion induction coil1 ,fig4 #abf1 are connect$ to a ,leyd5 j>1 & ! latt] is dis*>g+ disruptively into a circuit1 we may look ^u ! arc play+ betwe5 ! knobs z be+ a s\rce ( alt]nat+1 or g5]ally speak+1 undulat+ curr5ts1 & !n we h to deal ) ! famili> sy/em ( a g5]ator ( su* curr5ts1 a circuit connect$ to x1 & a cond5s] bridg+ ! circuit4 ,! cond5s] 9 su* case is a v]itable trans=m]1 & s9ce ! frequ5cy is excessive1 almo/ any ratio 9 ! /r5g? ( ! curr5ts 9 bo? ! bran*es may be obta9$4 ,9 reality ! analogy is n q complete1 = 9 ! disruptive dis*>ge we h mo/ g5]ally a fundam5tal in/antane\s v>iation ( comp>atively l[ frequ5cy1 & a sup]impos$ h>monic vibration1 & ! laws gov]n+ ! fl[ ( curr5ts are n ! same = bo?4 ,9 conv]t+ 9 ?is mann]1 ! ratio ( conv]sion %\ld n be too great1 = ! loss 9 ! arc betwe5 ! knobs increases ) ! squ>e ( ! curr5t1 & if ! j> be dis*>g$ ?r\gh v ?ick & %ort conductors1 ) ! view ( obta9+ a v rapid oscillation1 a v consid]able portion ( ! en]gy /or$ is lo/4 ,on ! o!r h&1 too small ratios are n practicable = _m obvi\s reasons4 ,z ! conv]t$ curr5ts fl[ 9 a practically clos$ circuit1 ! electro/atic effects are necess>ily small1 & ,i !re=e conv]t !m into curr5ts or effects ( ! requir$ "*4 ,i h effect$ su* conv]sions 9 sev]al ways4 ,! pref]r$ plan ( connections is illu/rat$ 9 ,fig4 #abg4 ,! mann] ( op]at+ r5d]s x easy to obta9 by means ( a small & inexp5sive app>atus enorm\s diff]5ces ( pot5tial :i* h be5 usually obta9$ by means ( l>ge & exp5sive coils4 ,= ?is x is only necess>y to take an ord9>y small coil1 adju/ to x a cond5s] & dis*>g+ circuit1 =m+ ! prim>y ( an auxili>y small coil1 & conv]t upw>d4 ,z ! inductive effect ( ! prim>y curr5ts is excessively great1 ! second coil ne$ h comp>atively b v few turns4 ,by prop]ly adju/+ ! elem5ts1 rem>kable results may be secur$4 ,9 endeavor+ to obta9 ! requir$ electro/atic effects 9 ?is mann]1 ,i h1 z might be expect$1 enc\nt]$ _m difficulties :i* ,i h be5 gradually ov]com+1 b ,i am n z yet prep>$ to dwell ^u my exp]i5ces 9 ?is direction4 ,i believe t ! disruptive dis*>ge ( a cond5s] w play an important "p 9 ! future1 = x (f]s va/ possibilities1 n only 9 ! way ( produc+ light 9 a m effici5t mann] & 9 ! l9e indicat$ by !ory1 b also 9 _m o!r respects4 ,illu/ration3 ,,fig4 #abf4 ,= ye>s ! ef=ts ( inv5tors h be5 direct$ t[>ds obta9+ electrical en]gy f heat by means ( ! !rmopile4 ,x might seem invidi\s to rem>k t b few "k :at is ! real tr\ble ) ! !rmopile4 ,x is n ! ineffici5cy or small output--?\gh ^! are great drawbacks--b ! fact t ! !rmopile has its phyllox]a1 t is1 t by con/ant use x is det]iorat$1 :i* has ?us f> prev5t$ its introduction on an indu/rial scale4 ,n[ t all mod]n rese>* seems to po9t ) c]ta9ty to ! use ( electricity ( excessively high t5sion1 ! "q mu/ pres5t itself to _m :e!r x is n possible to obta9 9 a practicable mann] ?is =m ( en]gy f heat4 ,we h be5 us$ to look ^u an electro/atic ma*9e z a play?+1 & someh[ we c\ple ) x ! idea ( ! ineffici5t & impractical4 ,b n[ we mu/ ?9k diff]5tly1 = n[ we "k t ev]y:]e we h to deal ) ! same =ces1 & t x is a m]e "q ( inv5t+ prop] me?ods or app>atus = r5d]+ !m available4 ,9 ! pres5t sy/ems ( electrical di/ribution1 ! employm5t ( ! iron ) its wond]ful magnetic prop]ties all[s u to r$uce consid]ably ! size ( ! app>atus2 b1 9 spite ( ?is1 x is /ill v cumb]some4 ,! m we progress 9 ! /udy ( electric & magnetic ph5om5a1 ! m we become conv9c$ t ! pres5t me?ods w be %ort-liv$4 ,= ! production ( light1 at lea/1 su* heavy ma*9]y w\ld seem to be unnecess>y4 ,! en]gy requir$ is v small1 & if light c be obta9$ z effici5tly z1 !oretically1 x appe>s possible1 ! app>atus ne$ h b a v small output4 ,!re be+ a /rong probability t ! illum9at+ me?ods ( ! future w involve ! use ( v high pot5tials1 x seems v desirable to p]fect a contrivance capable ( conv]t+ ! en]gy ( heat into en]gy ( ! requisite =m4 ,no?+ to speak ( has be5 done t[>ds ?is end1 = ! ?\ght t electricity ( "s #ej1jjj or #ajj1jjj volts pressure or m1 ev5 if obta9$1 w\ld be unavailable = practical purposes1 has det]r$ inv5tors f work+ 9 ?is direction4 ,illu/ration3 ,,fig4 #abg4 ,9 ,fig4 #abf a plan ( connections is %[n = conv]t+ curr5ts ( high1 into curr5ts ( l[1 t5sion by means ( ! disruptive dis*>ge ( a cond5s]4 ,?is plan has be5 us$ by me frequ5tly = op]at+ a few inc&esc5t lamps requir$ 9 ! laboratory4 ,"s difficulties h be5 enc\nt]$ 9 ! arc ( ! dis*>ge :i* ,i h be5 able to ov]come to a great ext5t2 besides ?is1 & ! adju/m5t necess>y = ! prop] work+1 no o!r difficulties h be5 met )1 & x 0 easy to op]ate ord9>y lamps1 & ev5 motors1 9 ?is mann]4 ,! l9e be+ connect$ to ! gr\nd1 all ! wires c\ld be h&l$ ) p]fect impunity1 no matt] h[ high ! pot5tial at ! t]m9als ( ! cond5s]4 ,9 ^! exp]im5ts a high t5sion induction coil1 op]at$ f a batt]y or f an alt]nate curr5t ma*9e1 0 employ$ to *>ge ! cond5s]2 b ! induction coil might be replac$ by an app>atus ( a diff]5t k9d1 capable ( giv+ electricity ( su* high t5sion4 ,9 ?is mann]1 direct or alt]nat+ curr5ts may be conv]t$1 & 9 bo? cases ! curr5t-impulses may be ( any desir$ frequ5cy4 ,:5 ! curr5ts *>g+ ! cond5s] are ( ! same direction1 & x is desir$ t ! conv]t$ curr5ts %\ld also be ( "o direction1 ! resi/ance ( ! dis*>g+ circuit %\ld1 ( c\rse1 be s *os5 t !re are no oscillations4 ,illu/ration3 ,,fig4 #abh4 ,9 op]at+ devices on ! above plan ,i h obs]v$ curi\s ph5om5a ( imp$ance :i* are ( int]e/4 ,= in/ance if a ?ick copp] b> be b5t1 z indicat$ 9 ,fig4 #abh1 & %unt$ by ord9>y inc&esc5t lamps1 !n1 by pass+ ! dis*>ge betwe5 ! knobs1 ! lamps may be br\ght to inc&esc5ce al?\gh !y are %ort-circuit$4 ,:5 a l>ge induction coil is employ$ x is easy to obta9 nodes on ! b>1 :i* are r5d]$ evid5t by ! diff]5t degree ( brilliancy ( ! lamps1 z %[n r\ghly 9 ,fig4 #abh4 ,! nodes are nev] cle>ly def9$1 b !y are simply maxima & m9ima ( pot5tials along ! b>4 ,?is is probably due to ! irregul>ity ( ! arc betwe5 ! knobs4 ,9 g5]al :5 ! above-describ$ plan ( conv]sion f high to l[ t5sion is us$1 ! behavior ( ! disruptive dis*>ge may be closely /udi$4 ,! nodes may also be inve/igat$ by means ( an ord9>y ,c>dew voltmet] :i* %\ld be well insulat$4 ,geissl] tubes may also be light$ across ! po9ts ( ! b5t b>2 9 ?is case1 ( c\rse1 x is bett] to employ small] capacities4 ,i h f\nd x practicable to light up 9 ?is mann] a lamp1 & ev5 a ,geissl] tube1 %unt$ by a %ort1 heavy block ( metal1 & ?is result seems at fir/ v curi\s4 ,9 fact1 ! ?ick] ! copp] b> 9 ,fig4 #abh1 ! bett] x is = ! success ( ! exp]im5ts1 z !y appe> m /rik+4 ,:5 lamps ) long sl5d] filam5ts are us$ x w be (t5 not$ t ! filam5ts are f "t to "t viol5tly vibrat$1 ! vibration be+ smalle/ at ! nodal po9ts4 ,?is vibration seems to be due to an electro/atic action betwe5 ! filam5t & ! glass ( ! bulb4 ,illu/ration3 ,,fig4 #abi4 ,9 "s ( ! above exp]im5ts x is pref]able to use special lamps hav+ a /raight filam5t z %[n 9 ,fig4 #abi4 ,:5 su* a lamp is us$ a /ill m curi\s ph5om5on ?an ^? describ$ may be obs]v$4 ,! lamp may be plac$ across ! copp] b> & light$1 & by us+ some:at l>g] capacities1 or1 9 o!r words1 small] frequ5cies or small] impulsive imp$ances1 ! filam5t may be br\ght to any desir$ degree ( inc&esc5ce4 ,b :5 ! imp$ance is increas$1 a po9t is rea*$ :5 comp>atively little curr5t passes ?r\gh ! c>bon1 & mo/ ( x ?r\gh ! r>efi$ gas2 or p]haps x may be m correct to /ate t ! curr5t divides ne>ly ev5ly ?r\gh bo?1 9 spite ( ! enorm\s diff]5ce 9 ! resi/ance1 & ?is w\ld be true unless ! gas & ! filam5t behave diff]5tly4 ,x is !n not$ t ! :ole bulb is brilliantly illum9at$1 & ! ends ( ! lead+-9 wires become inc&esc5t & (t5 ?r[ (f sp>ks 9 consequ5ce ( ! viol5t bomb>dm5t1 b ! c>bon filam5t rema9s d>k4 ,?is is illu/rat$ 9 ,fig4 #abi4 ,in/ead ( ! filam5t a s+le wire ext5d+ ?r\gh ! :ole bulb may be us$1 & 9 ?is case ! ph5om5on w\ld seem to be /ill m int]e/+4 ,f ! above exp]im5t x w be evid5t1 t :5 ord9>y lamps are op]at$ by ! conv]t$ curr5ts1 ^? %\ld be pref]ably tak5 9 :i* ! plat9um wires are f> ap>t1 & ! frequ5cies us$ %\ld n be too great1 else ! dis*>ge w occur at ! ends ( ! filam5t or 9 ! base ( ! lamp betwe5 ! lead+-9 wires1 & ! lamp might !n be damag$4 ,9 pres5t+ to y ^! results ( my inve/igation on ! subject "u consid]ation1 ,i h paid only a pass+ notice to facts ^u :i* ,i c\ld h dwelt at l5g?1 & among _m obs]vations ,i h select$ only ^? :i* ,i ?\ght mo/ likely to int]e/ y4 ,! field is wide & completely unexplor$1 & at e /ep a new tru? is glean$1 a novel fact obs]v$4 ,h[ f> ! results "h borne out are capable ( practical applications w be decid$ 9 ! future4 ,z reg>ds ! production ( light1 "s results already rea*$ are enc\rag+ & make me confid5t 9 ass]t+ t ! practical solution ( ! problem lies 9 ! direction ,i h endeavor$ to indicate4 ,/ill1 :atev] may be ! imm$iate outcome ( ^! exp]im5ts ,i am hopeful t !y w only prove a /ep 9 fur!r developm5t t[>ds ! ideal & f9al p]fection4 ,! possibilities :i* are op5$ by mod]n rese>* are s va/ t ev5 ! mo/ res]v$ mu/ feel sangu9e ( ! future4 ,em95t sci5ti/s consid] ! problem ( utiliz+ "o k9d ( radiation )\t ! o!rs a rational "o4 ,9 an app>atus design$ = ! production ( light by conv]sion f any =m ( en]gy into t ( light1 su* a result c nev] be rea*$1 = no matt] :at ! process ( produc+ ! requir$ vibrations1 be x electrical1 *emical or any o!r1 x w n be possible to obta9 ! high] light vibrations )\t go+ ?r\gh ! l[] heat vibrations4 ,x is ! problem ( imp>t+ to a body a c]ta9 velocity )\t pass+ ?r\gh all l[] velocities4 ,b !re is a possibility ( obta9+ en]gy n only 9 ! =m ( light1 b motive p[]1 & en]gy ( any o!r =m1 9 "s m direct way f ! m$ium4 ,! "t w be :5 ?is w be accompli%$1 & ! "t has come :5 "o may utt] su* words be=e an enlight5$ audi5ce )\t be+ consid]$ a vision>y4 ,we are :irl+ ?r\gh endless space ) an inconceivable spe$1 all ar\nd u ev]y?+ is sp9n+1 ev]y?+ is mov+1 ev]y:]e is en]gy4 ,!re mu/ be "s way ( avail+ ourselves ( ?is en]gy m directly4 ,!n1 ) ! light obta9$ f ! m$ium1 ) ! p[] d]iv$ f x1 ) e =m ( en]gy obta9$ )\t ef=t1 f ! /ore =ev] inexhau/ible1 humanity w advance ) giant /rides4 ,! m]e contemplation ( ^! magnific5t possibilities exp&s our m9ds1 /r5g!ns our hopes & fills our he>ts ) supreme delight4 ,,*apt] ,,xxvii4 ,,exp]im5ts ,,) ,,alt]nate ,,curr5ts ,,( ,,high ,,pot5tial ,,& ,,high ,,frequ5cy4#b #b ,lecture deliv]$ be=e ! ,in/itution ( ,electrical ,eng9e]s1 ,london1 ,febru>y1 #ahib4 ,i _c f9d words to express h[ deeply ,i feel ! honor ( address+ "s ( ! =emo/ ?9k]s ( ! pres5t "t1 & s _m able sci5tific m51 eng9e]s & electricians1 ( ! c\ntry greate/ 9 sci5tific a*ievem5ts4 ,! results :i* ,i h ! honor to pres5t be=e su* a ga!r+ ,i _c call my own4 ,!re are among y n a few :o c lay bett] claim ?an myself on any feature ( m]it :i* ?is "w may conta94 ,i ne$ n m5tion _m names :i* are _w-kn[n--names ( ^? among y :o are recogniz$ z ! lead]s 9 ?is en*ant+ sci5ce2 b "o1 at lea/1 ,i mu/ m5tion--a "n :i* c\ld n be omitt$ 9 a demon/ration ( ?is k9d4 ,x is a "n associat$ ) ! mo/ beautiful inv5tion ev] made3 x is ,crookes6 ,:5 ,i 0 at college1 a good :ile ago1 ,i read1 9 a translation 7= !n ,i 0 n famili> ) y\r magnific5t language71 ! description ( 8 exp]im5ts on radiant matt]4 ,i read x only once 9 my life--t "t--yet e detail ab\t t *>m+ "w ,i c rememb] to ?is day4 ,few are ! books1 let me say1 :i* c make su* an impression ^u ! m9d ( a /ud5t4 ,b if1 on ! pres5t occasion1 ,i m5tion ?is "n z "o ( _m y\r ,in/itution c boa/ (1 x is because ,i h m ?an "o reason to d s4 ,= :at ,i h to tell y & to %[ y ?is ev5+ conc]ns1 9 a l>ge measure1 t same vague _w :i* ,pr(essor ,crookes has s ably explor$2 &1 m ?an ?is1 :5 ,i trace back ! m5tal process :i* l$ me to ^! advances--:i* ev5 by myself _c be consid]$ trifl+1 s9ce !y are s appreciat$ by y--,i believe t _! real orig91 t :i* />t$ me to "w 9 ?is direction1 & br\ght me to !m1 aft] a long p]iod ( con/ant ?\ght1 0 t fasc9at+ little book :i* ,i read _m ye>s ago4 ,& n[ t ,i h made a feeble ef=t to express my homage & ackn[l$ge my indebt$ness to him & o!rs among y1 ,i w make a second ef=t1 :i* ,i hope y w n f9d s feeble z ! fir/1 to ent]ta9 y4 ,give me leave to introduce ! subject 9 a few words4 ,a %ort "t ago ,i _h ! honor to br+ be=e our ,am]ican ,in/itute ( ,electrical ,eng9e]s "s results !n arriv$ at by me 9 a novel l9e ( "w4 ,i ne$ n assure y t ! _m evid5ces :i* ,i h receiv$ t ,engli% sci5tific m5 & eng9e]s 7 int]e/$ 9 ?is "w h be5 = me a great rew>d & enc\ragem5t4 ,i w n dwell ^u ! exp]im5ts already describ$1 except ) ! view ( complet+1 or m cle>ly express+1 "s ideas advanc$ by me be=e1 & also ) ! view ( r5d]+ ! /udy "h pres5t$ self-conta9$1 & my rem>ks on ! subject ( ?is ev5+'s lecture consi/5t4 ,?is inve/igation1 !n1 x goes )\t say+1 deals ) alt]nat+ curr5ts1 & to be m precise1 ) alt]nat+ curr5ts ( high pot5tial & high frequ5cy4 ,j 9 h[ mu* a v high frequ5cy is ess5tial = ! production ( ! results pres5t$ is a "q :i*1 ev5 ) my pres5t exp]i5ce1 w\ld emb>rass me to answ]4 ,"s ( ! exp]im5ts may be p]=m$ ) l[ frequ5cies2 b v high frequ5cies are desirable1 n only on acc\nt ( ! _m effects secur$ by _! use1 b also z a conv5i5t means ( obta9+1 9 ! induction app>atus employ$1 ! high pot5tials1 :i* 9 _! turn are necess>y to ! demon/ration ( mo/ ( ! exp]im5ts "h contemplat$4 ,( ! v>i\s bran*es ( electrical inve/igation1 p]haps ! mo/ int]e/+ & ! mo/ imm$iately promis+ is t deal+ ) alt]nat+ curr5ts4 ,! progress 9 ?is bran* ( appli$ sci5ce has be5 s great 9 rec5t ye>s t x ju/ifies ! mo/ sangu9e hopes4 ,h>dly h we become famili> ) "o fact1 :5 novel exp]i5ces are met & new av5ues ( rese>* are op5$4 ,ev5 at ?is h\r possibilities n dream$ ( be=e are1 by ! use ( ^! curr5ts1 p>tly realiz$4 ,z 9 nature all is ebb & tide1 all is wave motion1 s x seems t 9 all bran*es ( indu/ry alt]nat+ curr5ts--electric wave motion--w h ! sway4 ,"o reason1 p]haps1 :y ?is bran* ( sci5ce is be+ s rapidly develop$ is to be f\nd 9 ! int]e/ :i* is atta*$ to its exp]im5tal /udy4 ,we w9d a simple r+ ( iron ) coils2 we e/abli% ! connections to ! g5]ator1 & ) wond] & delight we note ! effects ( /range =ces :i* we br+ into play1 :i* all[ u to trans=m1 to transmit & direct en]gy at w4 ,we arrange ! circuits prop]ly1 & we see ! mass ( iron & wires behave z ?\gh x 7 end[$ ) life1 sp9n+ a heavy armature1 ?r\gh invisible connections1 ) great spe$ & p[]--) ! en]gy possibly convey$ f a great di/ance4 ,we obs]ve h[ ! en]gy ( an alt]nat+ curr5t trav]s+ ! wire manife/s itself--n s mu* 9 ! wire z 9 ! surr\nd+ space--9 ! mo/ surpris+ mann]1 tak+ ! =ms ( heat1 light1 me*anical en]gy1 &1 mo/ surpris+ ( all1 ev5 *emical aff9ity4 ,all ^! obs]vations fasc9ate u1 & fill u ) an int5se desire to "k m ab\t ! nature ( ^! ph5om5a4 ,ea* day we g to our "w 9 ! hope ( discov]+1--9 ! hope t "s "o1 no matt] :o1 may f9d a solution ( "o ( ! p5d+ great problems1--& ea* succe$+ day we return to our task ) r5ew$ ardor2 & ev5 if we are unsuccessful1 our "w has n be5 9 va91 = 9 ^! /riv+s1 9 ^! ef=ts1 we h f\nd h\rs ( untold pleasure1 & we h direct$ our en]gies to ! b5efit ( mank9d4 ,we may take--at r&om1 if y *oose--any ( ! _m exp]im5ts :i* may be p]=m$ ) alt]nat+ curr5ts2 a few ( :i* only1 & by no means ! mo/ /rik+1 =m ! subject ( ?is ev5+'s demon/ration2 !y are all equally int]e/+1 equally incit+ to ?\ght4 ,"h is a simple glass tube f :i* ! air has be5 p>tially exhau/$4 ,i take hold ( x2 ,i br+ my body 9 contact ) a wire convey+ alt]nat+ curr5ts ( high pot5tial1 & ! tube 9 my h& is brilliantly light$4 ,9 :atev] position ,i may put x1 :]ev] ,i move x 9 space1 z f> z ,i c rea*1 its s(t1 pleas+ light p]si/s ) undim9i%$ brightness4 ,"h is an exhau/$ bulb susp5d$ f a s+le wire4 ,/&+ on an insulat$ support1 ,i grasp x1 & a plat9um button m\nt$ 9 x is br\ght to vivid inc&esc5ce4 ,"h1 atta*$ to a lead+ wire1 is ano!r bulb1 :i*1 z ,i t\* its metallic socket1 is fill$ ) magnific5t colors ( phosphoresc5t light4 ,"h /ill ano!r1 :i* by my f+]s' t\* ca/s a %ad[--! ,crookes %ad[--( ! /em inside ( x4 ,"h1 aga91 insulat$ z ,i /& on ?is plat=m1 ,i br+ my body 9 contact ) "o ( ! t]m9als ( ! second>y ( ?is induction coil--) ! end ( a wire _m miles long--& y see /reams ( light break =? f its di/ant end1 :i* is set 9 viol5t vibration4 ,"h1 once m1 ,i atta* ^! two plates ( wire gauze to ! t]m9als ( ! coil2 ,i set !m a di/ance ap>t1 & ,i set ! coil to "w4 ,y may see a small sp>k pass betwe5 ! plates4 ,i ins]t a ?ick plate ( "o ( ! be/ dielectrics betwe5 !m1 & in/ead ( r5d]+ altoge!r impossible1 z we are us$ to expect1 ,i aid ! passage ( ! dis*>ge1 :i*1 z ,i ins]t ! plate1 m]ely *anges 9 appe>ance & assumes ! =m ( lum9\s /reams4 ,is !re1 ,i ask1 c !re be1 a m int]e/+ /udy ?an t ( alt]nat+ curr5ts8 ,9 all ^! inve/igations1 9 all ^! exp]im5ts1 :i* are s v1 v int]e/+1 = _m ye>s pa/--ev] s9ce ! greate/ exp]im5t] :o lectur$ 9 ?is hall discov]$ its pr9ciple--we h _h a /eady companion1 an appliance famili> to e "o1 a play?+ once1 a ?+ ( mom5t\s importance n[--! induction coil4 ,!re is no de>] appliance to ! electrician4 ,f ! able/ among y1 ,i d>e say1 d[n to ! inexp]i5c$ /ud5t1 to y\r lectur]1 we all h pass$ _m delightful h\rs 9 exp]im5t+ ) ! induction coil4 ,we h wat*$ its play1 & ?\ght & pond]$ ov] ! beautiful ph5om5a :i* x disclos$ to our ravi%$ eyes4 ,s well kn[n is ?is app>atus1 s famili> are ^! ph5om5a to e "o1 t my c\rage ne>ly fails me :5 ,i ?9k t ,i h v5tur$ to address s able an audi5ce1 t ,i h v5tur$ to ent]ta9 y ) t same old subject4 ,"h 9 reality is ! same app>atus1 & "h are ! same ph5om5a1 only ! app>atus is op]at$ some:at diff]5tly1 ! ph5om5a are pres5t$ 9 a diff]5t aspect4 ,"s ( ! results we f9d z expect$1 o!rs surprise u1 b all captivate our att5tion1 = 9 sci5tific inve/igation ea* novel result a*iev$ may be ! c5tre ( a new dep>ture1 ea* novel fact le>n$ may lead to important developm5ts4 ,usually 9 op]at+ an induction coil we h set up a vibration ( mod]ate frequ5cy 9 ! prim>y1 ei!r by means ( an int]rupt] or break1 or by ! use ( an alt]nator4 ,e>li] ,engli% inve/igators1 to m5tion only ,spottiswoode & ,j4 ,e4 ,h4 ,gordon1 h us$ a rapid break 9 connection ) ! coil4 ,our k & exp]i5ce ( to-day enables u to see cle>ly :y ^! coils "u ! conditions ( ! te/ did n disclose any rem>kable ph5om5a1 & :y able exp]im5t]s fail$ to p]ceive _m ( ! curi\s effects :i* h s9ce be5 obs]v$4 ,9 ! exp]im5ts su* z p]=m$ ?is ev5+1 we op]ate ! coil ei!r f a specially con/ruct$ alt]nator capable ( giv+ _m ?\s&s ( rev]sals ( curr5t p] second1 or1 by disruptively dis*>g+ a cond5s] ?r\gh ! prim>y1 we set up a vibration 9 ! second>y circuit ( a frequ5cy ( _m hundr$ ?\s& or millions p] second1 if we s desire2 & 9 us+ ei!r ( ^! means we ent] a field z yet unexplor$4 ,x is impossible to pursue an inve/igation 9 any novel l9e )\t f9ally mak+ "s int]e/+ obs]vation or le>n+ "s useful fact4 ,t ?is /atem5t is applicable to ! subject ( ?is lecture ! _m curi\s & unexpect$ ph5om5a :i* we obs]ve af=d a conv9c+ pro(4 ,by way ( illu/ration1 take = in/ance ! mo/ obvi\s ph5om5a1 ^? ( ! dis*>ge ( ! induction coil4 ,"h is a coil :i* is op]at$ by curr5ts vibrat+ ) extreme rapidity1 obta9$ by disruptively dis*>g+ a ,leyd5 j>4 ,x w\ld n surprise a /ud5t 7 ! lectur] to say t ! second>y ( ?is coil consi/s ( a small l5g? ( comp>atively /\t wire2 x w\ld n surprise him 7 ! lectur] to /ate t1 9 spite ( ?is1 ! coil is capable ( giv+ any pot5tial :i* ! be/ insulation ( ! turns is able to )/&2 b al?\gh he may be prep>$1 & ev5 be indiff]5t z to ! anticipat$ result1 yet ! aspect ( ! dis*>ge ( ! coil w surprise & int]e/ him4 ,e "o is famili> ) ! dis*>ge ( an ord9>y coil2 x ne$ n be reproduc$ "h4 ,b1 by way ( contra/1 "h is a =m ( dis*>ge ( a coil1 ! prim>y curr5t ( :i* is vibrat+ sev]al hundr$ ?\s& times p] second4 ,! dis*>ge ( an ord9>y coil appe>s z a simple l9e or b& ( light4 ,! dis*>ge ( ?is coil appe>s 9 ! =m ( p[]ful bru%es & lum9\s /reams issu+ f all po9ts ( ! two /raight wires atta*$ to ! t]m9als ( ! second>y4 7,fig4 #acj47 ,illu/ration3 ,,fig4 #acj4 ,illu/ration3 ,,fig4 #aca4 ,n[ comp>e ?is ph5om5on :i* y h j witness$ ) ! dis*>ge ( a ,holtz or ,wim%ur/ ma*9e--t o!r int]e/+ appliance s de> to ! exp]im5t]4 ,:at a diff]5ce !re is betwe5 ^! ph5om5a6 ,& yet1 _h ,i made ! necess>y arrangem5ts--:i* c\ld h be5 made easily1 7 x n t !y w\ld int]f]e ) o!r exp]im5ts--,i c\ld h produc$ ) ?is coil sp>ks :i*1 _h ,i ! coil hidd5 f y\r view & only two knobs expos$1 ev5 ! ke5e/ obs]v] among y w\ld f9d x difficult1 if n impossible1 to di/+ui% f ^? ( an influ5ce or friction ma*9e4 ,?is may be done 9 _m ways--= in/ance1 by op]at+ ! induction coil :i* *>ges ! cond5s] f an alt]nat+-curr5t ma*9e ( v l[ frequ5cy1 & pref]ably adju/+ ! dis*>ge circuit s t !re are no oscillations set up 9 x4 ,we !n obta9 9 ! second>y circuit1 if ! knobs are ( ! requir$ size & prop]ly set1 a m or less rapid succession ( sp>ks ( great int5sity & small quantity1 :i* possess ! same brilliancy1 & are accompani$ by ! same %>p crackl+ s\nd1 z ^? obta9$ f a friction or influ5ce ma*9e4 ,ano!r way is to pass ?r\gh two prim>y circuits1 hav+ a common second>y1 two curr5ts ( a slightly diff]5t p]iod1 :i* produce 9 ! second>y circuit sp>ks occurr+ at comp>atively long int]vals4 ,b1 ev5 ) ! means at h& ?is ev5+1 ,i may succe$ 9 imitat+ ! sp>k ( a ,holtz ma*9e4 ,= ?is purpose ,i e/abli% betwe5 ! t]m9als ( ! coil :i* *>ges ! cond5s] a long1 un/eady arc1 :i* is p]iodically int]rupt$ by ! upw>d curr5t ( air produc$ by x4 ,to increase ! curr5t ( air ,i place on ea* side ( ! arc1 & close to x1 a l>ge plate ( mica4 ,! cond5s] *>g$ f ?is coil dis*>ges into ! prim>y circuit ( a second coil ?r\gh a small air gap1 :i* is necess>y to produce a sudd5 ru% ( curr5t ?r\gh ! prim>y4 ,! s*eme ( connections 9 ! pres5t exp]im5t is indicat$ 9 ,fig4 #aca4 ,g is an ord9>ily con/ruct$ alt]nator1 supply+ ! prim>y ,p ( an induction coil1 ! second>y ,s ( :i* *>ges ! cond5s]s or j>s ,c ,c4 ,! t]m9als ( ! second>y are connect$ to ! inside coat+s ( ! j>s1 ! out] coat+s be+ connect$ to ! ends ( ! prim>y p p ( a second induction coil4 ,?is prim>y p p has a small air gap a b4 ,! second>y s ( ?is coil is provid$ ) knobs or sph]es ,k ,k ( ! prop] size & set at a di/ance suitable = ! exp]im5t4 ,a long arc is e/abli%$ betwe5 ! t]m9als ,a ,b ( ! fir/ induction coil4 ,m ,m are ! mica plates4 ,ea* "t ! arc is brok5 betwe5 ,a & ,b ! j>s are quickly *>g$ & dis*>g$ ?r\gh ! prim>y p p1 produc+ a snapp+ sp>k betwe5 ! knobs ,k ,k4 ,^u ! arc =m+ betwe5 ,a & ,b ! pot5tial falls1 & ! j>s _c be *>g$ to su* high pot5tial z to break ?r\gh ! air gap a b until ! arc is aga9 brok5 by ! draught4 ,9 ?is mann] sudd5 impulses1 at long int]vals1 are produc$ 9 ! prim>y p p1 :i* 9 ! second>y s give a correspond+ numb] ( impulses ( great int5sity4 ,if ! second>y knobs or sph]es1 ,k ,k1 are ( ! prop] size1 ! sp>ks %[ mu* resemblance to ^? ( a ,holtz ma*9e4 ,b ^! two effects1 :i* to ! eye appe> s v diff]5t1 are only two ( ! _m dis*>ge ph5om5a4 ,we only ne$ to *ange ! conditions ( ! te/1 & aga9 we make o!r obs]vations ( int]e/4 ,:51 in/ead ( op]at+ ! induction coil z 9 ! la/ two exp]im5ts1 we op]ate x f a high frequ5cy alt]nator1 z 9 ! next exp]im5t1 a sy/ematic /udy ( ! ph5om5a is r5d]$ mu* m easy4 ,9 su* case1 9 v>y+ ! /r5g? & frequ5cy ( ! curr5ts ?r\gh ! prim>y1 we may obs]ve five di/9ct =ms ( dis*>ge1 :i* ,i h describ$ 9 my =m] pap] on ! subject be=e ! ,am]ican ,in/itute ( ,electrical ,eng9e]s1 ,may #bj1 #ahia4 ,x w\ld take too mu* "t1 & x w\ld lead u too f> f ! subject pres5t$ ?is ev5+1 to reproduce all ^! =ms1 b x seems to me desirable to %[ y "o ( !m4 ,x is a bru% dis*>ge1 :i* is int]e/+ 9 m ?an "o respect4 ,view$ f a ne> position x resembles mu* a jet ( gas escap+ "u great pressure4 ,we "k t ! ph5om5on is due to ! agitation ( ! molecules ne> ! t]m9al1 & we anticipate t "s heat mu/ be develop$ by ! impact ( ! molecules aga9/ ! t]m9al or aga9/ ea* o!r4 ,inde$1 we f9d t ! bru% is hot1 & only a little ?\ght leads u to ! conclusion t1 c\ld we b rea* suffici5tly high frequ5cies1 we c\ld produce a bru% :i* w\ld give int5se light & heat1 & :i* w\ld resemble 9 e p>ticul> an ord9>y flame1 save1 p]haps1 t bo? ph5om5a might n be due to ! same ag5t--save1 p]haps1 t *emical aff9ity might n be electrical 9 its nature4 ,z ! production ( heat & light is "h due to ! impact ( ! molecules1 or atoms ( air1 or some?+ else besides1 &1 z we c augm5t ! en]gy simply by rais+ ! pot5tial1 we might1 ev5 ) frequ5cies obta9$ f a dynamo ma*9e1 int5sify ! action to su* a degree z to br+ ! t]m9al to melt+ heat4 ,b ) su* l[ frequ5cies we w\ld h to deal always ) some?+ ( ! nature ( an electric curr5t4 ,if ,i approa* a conduct+ object to ! bru%1 a ?9 little sp>k passes1 yet1 ev5 ) ! frequ5cies us$ ?is ev5+1 ! t5d5cy to sp>k is n v great4 ,s1 = in/ance1 if ,i hold a metallic sph]e at "s di/ance above ! t]m9al1 y may see ! :ole space betwe5 ! t]m9al & sph]e illum9at$ by ! /reams )\t ! sp>k pass+2 & ) ! mu* high] frequ5cies obta9able by ! disruptive dis*>ge ( a cond5s]1 7 x n = ! sudd5 impulses1 :i* are comp>atively few 9 numb]1 sp>k+ w\ld n occur ev5 at v small di/ances4 ,h[ev]1 ) incomp>ably high] frequ5cies1 :i* we may yet f9d means to produce effici5tly1 & provid$ t electric impulses ( su* high frequ5cies c\ld be transmitt$ ?r\gh a conductor1 ! electrical *>act]i/ics ( ! bru% dis*>ge w\ld completely vani%--no sp>k w\ld pass1 no %ock w\ld be felt--yet we w\ld /ill h to deal ) an electric ph5om5on1 b 9 ! broad1 mod]n int]pretation ( ! ^w4 ,9 my fir/ pap]1 be=e ref]r$ to1 ,i h po9t$ out ! curi\s prop]ties ( ! bru%1 & describ$ ! be/ mann] ( produc+ x1 b ,i h ?\ght x wor? :ile to endeavor to express myself m cle>ly 9 reg>d to ?is ph5om5on1 because ( its absorb+ int]e/4 ,:5 a coil is op]at$ ) curr5ts ( v high frequ5cy1 beautiful bru% effects may be produc$1 ev5 if ! coil be ( comp>atively small dim5sions4 ,! exp]im5t] may v>y !m 9 _m ways1 &1 if x 7 = no?+ else1 !y af=d a pleas+ sight4 ,:at adds to _! int]e/ is t !y may be produc$ ) "o s+le t]m9al z well z ) two--9 fact1 (t5 bett] ) "o ?an ) two4 ,b ( all ! dis*>ge ph5om5a obs]v$1 ! mo/ pleas+ to ! eye1 & ! mo/ in/ructive1 are ^? obs]v$ ) a coil :i* is op]at$ by means ( ! disruptive dis*>ge ( a cond5s]4 ,! p[] ( ! bru%es1 ! abundance ( ! sp>ks1 :5 ! conditions are pati5tly adju/$1 is (t5 amaz+4 ,) ev5 a v small coil1 if x be s well insulat$ z to /& a diff]5ce ( pot5tial ( sev]al ?\s& volts p] turn1 ! sp>ks may be s abundant t ! :ole coil may appe> a complete mass ( fire4 ,curi\sly en\gh ! sp>ks1 :5 ! t]m9als ( ! coil are set at a consid]able di/ance1 seem to d>t 9 e possible direction z ?\gh ! t]m9als 7 p]fectly indep5d5t ( ea* o!r4 ,z ! sp>ks w\ld soon de/roy ! insulation1 x is necess>y to prev5t !m4 ,?is is be/ done by imm]s+ ! coil 9 a good liquid insulator1 su* z boil$-out oil4 ,imm]sion 9 a liquid may be consid]$ almo/ an absolute necessity = ! cont9u$ & successful work+ ( su* a coil4 ,x is1 ( c\rse1 out ( ! "q1 9 an exp]im5tal lecture1 ) only a few m9utes at disposal = ! p]=mance ( ea* exp]im5t1 to %[ ^! dis*>ge ph5om5a to advantage1 z1 to produce ea* ph5om5on at its be/1 a v c>eful adju/m5t is requir$4 ,b ev5 if imp]fectly produc$1 z !y are likely to be ?is ev5+1 !y are suffici5tly /rik+ to int]e/ an intellig5t audi5ce4 ,be=e %[+ "s ( ^! curi\s effects ,i mu/1 = ! sake ( complet5ess1 give a %ort description ( ! coil & o!r app>atus us$ 9 ! exp]im5ts ) ! disruptive dis*>ge ?is ev5+4 ,illu/ration3 ,,fig4 #acb4 ,x is conta9$ 9 a box ,b 7,fig4 #acb7 ( ?ick bo>ds ( h>d wood1 cov]$ on ! outside ) a z9c %eet ,z1 :i* is c>efully sold]$ all ar\nd4 ,x might be advisable1 9 a /rictly sci5tific inve/igation1 :5 accuracy is ( great importance1 to d away ) ! metal cov]1 z x might introduce _m errors1 pr9cipally on acc\nt ( its complex action ^u ! coil1 z a cond5s] ( v small capacity & z an electro/atic & electromagnetic scre54 ,:5 ! coil is us$ = su* exp]im5ts z are "h contemplat$1 ! employm5t ( ! metal cov] (f]s "s practical advantages1 b ^! are n ( suffici5t importance to be dwelt ^u4 ,! coil %\ld be plac$ symmetrically to ! metal cov]1 & ! space betwe5 %\ld1 ( c\rse1 n be too small1 c]ta9ly n less ?an1 say1 five c5timetres1 b mu* m if possible2 especially ! two sides ( ! z9c box1 :i* are at "r angles to ! axis ( ! coil1 %\ld be suffici5tly remote f ! latt]1 z o!rwise !y might impair its action & be a s\rce ( loss4 ,! coil consi/s ( two spools ( h>d rubb] ,r ,r1 held ap>t at a di/ance ( #aj c5timetres by bolts ,c & nuts n1 likewise ( h>d rubb]4 ,ea* spool comprises a tube ,t ( approximately #h c5timetres inside diamet]1 & #c millimetres ?ick1 ^u :i* are screw$ two flanges ,f ,f1 #bd c5timetres squ>e1 ! space betwe5 ! flanges be+ ab\t #c c5timetres4 ,! second>y1 ,s ,s1 ( ! be/ gutta p]*a-cov]$ wire1 has #bf lay]s1 #aj turns 9 ea*1 giv+ = ea* half a total ( #bfj turns4 ,! two halves are w\nd oppositely & connect$ 9 s]ies1 ! connection betwe5 bo? be+ made ov] ! prim>y4 ,?is disposition1 besides be+ conv5i5t1 has ! advantage t :5 ! coil is well balanc$--t is1 :5 bo? ( its t]m9als ,t#a1 ,t#a1 are connect$ to bodies or devices ( equal capacity--!re is n mu* dang] ( break+ ?r\gh to ! prim>y1 & ! insulation betwe5 ! prim>y & ! second>y ne$ n be ?ick4 ,9 us+ ! coil x is advisable to atta* to bo? t]m9als devices ( ne>ly equal capacity1 z1 :5 ! capacity ( ! t]m9als is n equal1 sp>ks w be apt to pass to ! prim>y4 ,to avoid ?is1 ! middle po9t ( ! second>y may be connect$ to ! prim>y1 b ?is is n always practicable4 ,! prim>y ,p ,p is w\nd 9 two p>ts1 & oppositely1 ^u a wood5 spool w1 & ! f\r ends are l$ out ( ! oil ?r\gh h>d rubb] tubes t t4 ,! ends ( ! second>y ,t#a ,t#a1 are also l$ out ( ! oil ?r\gh rubb] tubes t#a t#a ( great ?ickness4 ,! prim>y & second>y lay]s are insulat$ by cotton clo?1 ! ?ickness ( ! insulation1 ( c\rse1 be>+ "s proportion to ! diff]5ce ( pot5tial betwe5 ! turns ( ! diff]5t lay]s4 ,ea* half ( ! prim>y has f\r lay]s1 #bd turns 9 ea*1 ?is giv+ a total ( #if turns4 ,:5 bo? ! p>ts are connect$ 9 s]ies1 ?is gives a ratio ( conv]sion ( ab\t #a3b4g1 & ) ! prim>ies 9 multiple1 #a3e4d2 b 9 op]at+ ) v rapidly alt]nat+ curr5ts ?is ratio does n convey ev5 an approximate idea ( ! ratio ( ! ,e4 ,m4 ,f's4 9 ! prim>y & second>y circuits4 ,! coil is held 9 position 9 ! oil on wood5 supports1 !re be+ ab\t #e c5timetres ?ickness ( oil all r\nd4 ,:]e ! oil is n specially ne$$1 ! space is fill$ ) pieces ( wood1 & = ?is purpose pr9cipally ! wood5 box ,b surr\nd+ ! :ole is us$4 ,! con/ruction "h %[n is1 ( c\rse1 n ! be/ on g5]al pr9ciples1 b ,i believe x is a good & conv5i5t "o = ! production ( effects 9 :i* an excessive pot5tial & a v small curr5t are ne$$4 ,9 connection ) ! coil ,i use ei!r ! ord9>y =m ( dis*>g] or a modifi$ =m4 ,9 ! =m] ,i h introduc$ two *anges :i* secure "s advantages1 & :i* are obvi\s4 ,if !y are m5tion$1 x is only 9 ! hope t "s exp]im5t] may f9d !m ( use4 ,"o ( ! *anges is t ! adju/able knobs ,a & ,b 7,fig4 #acc71 ( ! dis*>g] are held 9 jaws ( brass1 ,j ,j1 by spr+ pressure1 ?is all[+ ( turn+ !m successively into diff]5t positions1 & s do+ away ) ! t$i\s process ( frequ5t poli%+ up4 ,illu/ration3 ,,fig4 #acc4 ,! o!r *ange consi/s 9 ! employm5t ( a /rong electromagnet ,n ,s1 :i* is plac$ ) its axis at "r angles to ! l9e jo9+ ! knobs ,a & ,b1 & produces a /rong magnetic field betwe5 !m4 ,! pole pieces ( ! magnet are movable & prop]ly =m$ s z to protrude betwe5 ! brass knobs1 9 ord] to make ! field z int5se z possible2 b to prev5t ! dis*>ge f jump+ to ! magnet ! pole pieces are protect$ by a lay] ( mica1 ,m ,m1 ( suffici5t ?ickness2 s#a s#a & s#b s#b are screws = fa/5+ ! wires4 ,on ea* side "o ( ! screws is = l>ge & ! o!r = small wires4 ,l ,l are screws = fix+ 9 position ! rods ,r ,r1 :i* support ! knobs4 ,9 ano!r arrangem5t ) ! magnet ,i take ! dis*>ge betwe5 ! r\nd$ pole pieces !mselves1 :i* 9 su* case are insulat$ & pref]ably provid$ ) poli%$ brass caps4 ,! employm5t ( an int5se magnetic field is ( advantage pr9cipally :5 ! induction coil or trans=m] :i* *>ges ! cond5s] is op]at$ by curr5ts ( v l[ frequ5cy4 ,9 su* a case ! numb] ( ! fundam5tal dis*>ges betwe5 ! knobs may be s small z to r5d] ! curr5ts produc$ 9 ! second>y unsuitable = _m exp]im5ts4 ,! int5se magnetic field !n s]ves to bl[ out ! arc betwe5 ! knobs z soon z x is =m$1 & ! fundam5tal dis*>ges occur 9 quick] succession4 ,illu/ration3 ,,fig4 #acd4 ,in/ead ( ! magnet1 a draught or bla/ ( air may be employ$ ) "s advantage4 ,9 ?is case ! arc is pref]ably e/abli%$ betwe5 ! knobs ,a ,b1 9 ,fig4 #aca 7! knobs a b be+ g5]ally jo9$1 or entirely done away )71 z 9 ?is disposition ! arc is long & un/eady1 & is easily affect$ by ! draught4 ,:5 a magnet is employ$ to break ! arc1 x is bett] to *oose ! connection indicat$ diagrammatically 9 ,fig4 #acd1 z 9 ?is case ! curr5ts =m+ ! arc are mu* m p[]ful1 & ! magnetic field ex]cises a great] influ5ce4 ,! use ( ! magnet p]mits1 h[ev]1 ( ! arc be+ replac$ by a vacuum tube1 b ,i h enc\nt]$ great difficulties 9 work+ ) an exhau/$ tube4 ,! o!r =m ( dis*>g] us$ 9 ^! & simil> exp]im5ts is indicat$ 9 ,figs4 #ace & #acf4 ,x consi/s ( a numb] ( brass pieces c c 7,fig4 #ace71 ea* ( :i* comprises a sph]ical middle portion m ) an ext5sion e bel[--:i* is m]ely us$ to fa/5 ! piece 9 a la! :5 poli%+ up ! dis*>g+ surface--& a column above1 :i* consi/s ( a knurl$ flange f surm\nt$ by a ?read$ /em l c>ry+ a nut n1 by means ( :i* a wire is fa/5$ to ! column4 ,! flange f conv5i5tly s]ves = hold+ ! brass piece :5 fa/5+ ! wire1 & also = turn+ x 9 any position :5 x becomes necess>y to pres5t a fre% dis*>g+ surface4 ,two /\t /rips ( h>d rubb] ,r ,r1 ) plan$ grooves g g 7,fig4 #acf7 to fit ! middle portion ( ! pieces c c1 s]ve to clamp ! latt] & hold !m firmly 9 position by means ( two bolts ,c ,c 7( :i* only "o is %[n7 pass+ ?r\gh ! ends ( ! /rips4 ,illu/ration3 ,,fig4 #ace4 ,illu/ration3 ,,fig4 #acf4 ,9 ! use ( ?is k9d ( dis*>g] ,i h f\nd ?ree pr9cipal advantages ov] ! ord9>y =m4 ,fir/1 ! dielectric /r5g? ( a giv5 total wid? ( air space is great] :5 a great _m small air gaps are us$ in/ead ( "o1 :i* p]mits ( work+ ) a small] l5g? ( air gap1 & t means small] loss & less det]ioration ( ! metal2 secondly1 by reason ( splitt+ ! arc up into small] arcs1 ! poli%$ surfaces are made to la/ mu* long]2 &1 ?irdly1 ! app>atus af=ds "s gauge 9 ! exp]im5ts4 ,i usually set ! pieces by putt+ betwe5 !m %eets ( uni=m ?ickness at a c]ta9 v small di/ance :i* is kn[n f ! exp]im5ts ( ,sir ,william ,?omson to require a c]ta9 electromotive =ce to be bridg$ by ! sp>k4 ,x %\ld1 ( c\rse1 be rememb]$ t ! sp>k+ di/ance is mu* dim9i%$ z ! frequ5cy is increas$4 ,by tak+ any numb] ( spaces ! exp]im5t] has a r\gh idea ( ! electromotive =ce1 & he f9ds x easi] to repeat an exp]im5t1 z he has n ! tr\ble ( sett+ ! knobs aga9 & aga94 ,) ?is k9d ( dis*>g] ,i h be5 able to ma9ta9 an oscillat+ motion )\t any sp>k be+ visible ) ! nak$ eye betwe5 ! knobs1 & !y w\ld n %[ a v appreciable rise 9 temp]ature4 ,?is =m ( dis*>ge also l5ds itself to _m arrangem5ts ( cond5s]s & circuits :i* are (t5 v conv5i5t & "t-sav+4 ,i h us$ x pref]ably 9 a disposition simil> to t indicat$ 9 ,fig4 #aca1 :5 ! curr5ts =m+ ! arc are small4 ,i may "h m5tion t ,i h also us$ dis*>g]s ) s+le or multiple air gaps1 9 :i* ! dis*>ge surfaces 7 rotat$ ) great spe$4 ,no p>ticul> advantage 01 h[ev]1 ga9$ by ?is me?od1 except 9 cases :]e ! curr5ts f ! cond5s] 7 l>ge & ! keep+ cool ( ! surfaces 0 necess>y1 & 9 cases :51 ! dis*>ge n be+ oscillat+ ( itself1 ! arc z soon z e/abli%$ 0 brok5 by ! air curr5t1 ?us />t+ ! vibration at int]vals 9 rapid succession4 ,i h also us$ me*anical int]rupt]s 9 _m ways4 ,to avoid ! difficulties ) frictional contacts1 ! pref]r$ plan adopt$ 0 to e/abli% ! arc & rotate ?r\gh x at great spe$ a rim ( mica provid$ ) _m holes & fa/5$ to a /eel plate4 ,x is und]/ood1 ( c\rse1 t ! employm5t ( a magnet1 air curr5t1 or o!r int]rupt]1 produces no effect wor? notic+1 unless ! self-induction1 capacity & resi/ance are s relat$ t !re are oscillations set up ^u ea* int]ruption4 ,i w n[ endeavor to %[ y "s ( ! mo/ notewor?y ( ^! dis*>ge ph5om5a4 ,i h /ret*$ across ! room two ord9>y cotton cov]$ wires1 ea* ab\t sev5 metres 9 l5g?4 ,!y are support$ on insulat+ cords at a di/ance ( ab\t ?irty c5timetres4 ,i atta* n[ to ea* ( ! t]m9als ( ! coil "o ( ! wires1 & set ! coil 9 action4 ,^u turn+ ! lights (f 9 ! room y see ! wires /rongly illum9at$ by ! /reams issu+ abundantly f _! :ole surface 9 spite ( ! cotton cov]+1 :i* may ev5 be v ?ick4 ,:5 ! exp]im5t is p]=m$ "u good conditions1 ! light f ! wires is suffici5tly int5se to all[ di/+ui%+ ! objects 9 a room4 ,to produce ! be/ result x is1 ( c\rse1 necess>y to adju/ c>efully ! capacity ( ! j>s1 ! arc betwe5 ! knobs & ! l5g? ( ! wires4 ,my exp]i5ce is t calculation ( ! l5g? ( ! wires leads1 9 su* case1 to no result :atev]4 ,! exp]im5t] w d be/ to take ! wires at ! />t v long1 & !n adju/ by cutt+ (f fir/ long pieces1 & !n small] & small] ones z he approa*es ! "r l5g?4 ,a conv5i5t way is to use an oil cond5s] ( v small capacity1 consi/+ ( two small adju/able metal plates1 9 connection ) ?is & simil> exp]im5ts4 ,9 su* case ,i take wires r %ort & at ! beg9n+ set ! cond5s] plates at maximum di/ance4 ,if ! /reams f ! wires increase by approa* ( ! plates1 ! l5g? ( ! wires is ab\t "r2 if !y dim9i%1 ! wires are too long = t frequ5cy & pot5tial4 ,:5 a cond5s] is us$ 9 connection ) exp]im5ts ) su* a coil1 x %\ld be an oil cond5s] by all means1 z 9 us+ an air cond5s] consid]able en]gy might be wa/$4 ,! wires lead+ to ! plates 9 ! oil %\ld be v ?91 heavily coat$ ) "s insulat+ comp\nd1 & provid$ ) a conduct+ cov]+--?is pref]ably ext5d+ "u ! surface ( ! oil4 ,! conduct+ cov] %\ld n be too ne> ! t]m9als1 or ends1 ( ! wire1 z a sp>k w\ld be apt to jump f ! wire to x4 ,! conduct+ coat+ is us$ to dim9i% ! air losses1 9 virtue ( its action z an electro/atic scre54 ,z to ! size ( ! vessel conta9+ ! oil1 & ! size ( ! plates1 ! exp]im5t] ga9s at once an idea f a r\gh trial4 ,! size ( ! plates 9 oil is1 h[ev]1 calculable1 z ! dielectric losses are v small4 ,9 ! prec$+ exp]im5t x is ( consid]able int]e/ to "k :at relation ! quantity ( ! light emitt$ be>s to ! frequ5cy & pot5tial ( ! electric impulses4 ,my op9ion is t ! heat z well z light effects produc$ %\ld be proportionate1 "u o!rwise equal conditions ( te/1 to ! product ( frequ5cy & squ>e ( pot5tial1 b ! exp]im5tal v]ification ( ! law1 :atev] x may be1 w\ld be exce$+ly difficult4 ,"o ?+ is c]ta91 at any rate1 & t is1 t 9 augm5t+ ! pot5tial & frequ5cy we rapidly int5sify ! /reams2 &1 ?\gh x may be v sangu9e1 x is surely n altoge!r hopeless to expect t we may succe$ 9 produc+ a practical illum9ant on ^! l9es4 ,we w\ld !n be simply us+ burn]s or flames1 9 :i* !re w\ld be no *emical process1 no consumption ( mat]ial1 b m]ely a transf] ( en]gy1 & :i* w\ld1 9 all probability1 emit m light & less heat ?an ord9>y flames4 ,illu/ration3 ,,fig4 #acg4 ,! lum9\s int5sity ( ! /reams is1 ( c\rse1 consid]ably increas$ :5 !y are focus$ ^u a small surface4 ,?is may be %[n by ! foll[+ exp]im5t3 ,i atta* to "o ( ! t]m9als ( ! coil a wire w 7,fig4 #acg71 b5t 9 a circle ( ab\t #cj c5timetres 9 diamet]1 & to ! o!r t]m9al ,i fa/5 a small brass sph]e s1 ! surface ( ! wire be+ pref]ably equal to ! surface ( ! sph]e1 & ! c5tre ( ! latt] be+ 9 a l9e at "r angles to ! plane ( ! wire circle & pass+ ?r\gh its c5tre4 ,:5 ! dis*>ge is e/abli%$ "u prop] conditions1 a lum9\s holl[ cone is =m$1 & 9 ! d>k "o-half ( ! brass sph]e is /rongly illum9at$1 z %[n 9 ! cut4 ,by "s artifice or o!r x is easy to conc5trate ! /reams ^u small surfaces & to produce v /rong light effects4 ,two ?9 wires may ?us be r5d]$ int5sely lum9\s4 ,9 ord] to int5sify ! /reams ! wires %\ld be v ?9 & %ort2 b z 9 ?is case _! capacity w\ld be g5]ally too small = ! coil--at lea/ = su* a "o z ! pres5t--x is necess>y to augm5t ! capacity to ! requir$ value1 :ile1 at ! same "t1 ! surface ( ! wires rema9s v small4 ,?is may be done 9 _m ways4 ,illu/ration3 ,,fig4 #ach4 ,"h1 = in/ance1 ,i h two plates1 ,r ,r1 ( h>d rubb] 7,fig4 #ach71 ^u :i* ,i h glu$ two v ?9 wires w w1 s z to =m a "n4 ,! wires may be b>e or cov]$ ) ! be/ insulation--x is immat]ial = ! success ( ! exp]im5t4 ,well insulat$ wires1 if any?+1 are pref]able4 ,on ! back ( ea* plate1 indicat$ by ! %ad$ portion1 is a t9foil coat+ t t4 ,! plates are plac$ 9 l9e at a suffici5t di/ance to prev5t a sp>k pass+ f "o wire to ! o!r4 ,! two t9foil coat+s ,i h jo9$ by a conductor ,c1 & ! two wires ,i pres5tly connect to ! t]m9als ( ! coil4 ,x is n[ easy1 by v>y+ ! /r5g? & frequ5cy ( ! curr5ts ?r\gh ! prim>y1 to f9d a po9t at :i* ! capacity ( ! sy/em is be/ suit$ to ! conditions1 & ! wires become s /rongly lum9\s t1 :5 ! light 9 ! room is turn$ (f ! "n =m$ by !m appe>s 9 brilliant lett]s4 ,x is p]haps pref]able to p]=m ?is exp]im5t ) a coil op]at$ f an alt]nator ( high frequ5cy1 z !n1 ow+ to ! h>monic rise & fall1 ! /reams are v uni=m1 ?\gh !y are less abundant ?an :5 produc$ ) su* a coil z ! pres5t "o4 ,?is exp]im5t1 h[ev]1 may be p]=m$ ) l[ frequ5cies1 b mu* less satisfactorily4 ,illu/ration3 ,,fig4 #aci4 ,:5 two wires1 atta*$ to ! t]m9als ( ! coil1 are set at ! prop] di/ance1 ! /reams betwe5 !m may be s int5se z to produce a cont9u\s lum9\s %eet4 ,to %[ ?is ph5om5on ,i h "h two circles1 ,c & c 7,fig4 #aci71 ( r /\t wire1 "o be+ ab\t #hj c5timetres & ! o!r #cj c5timetres 9 diamet]4 ,to ea* ( ! t]m9als ( ! coil ,i atta* "o ( ! circles4 ,! support+ wires are s b5t t ! circles may be plac$ 9 ! same plane1 co9cid+ z ne>ly z possible4 ,:5 ! light 9 ! room is turn$ (f & ! coil set to "w1 y see ! :ole space betwe5 ! wires uni=mly fill$ ) /reams1 =m+ a lum9\s disc1 :i* c\ld be se5 f a consid]able di/ance1 su* is ! int5sity ( ! /reams4 ,! out] circle c\ld h be5 mu* l>g] ?an ! pres5t "o2 9 fact1 ) ?is coil ,i h us$ mu* l>g] circles1 & ,i h be5 able to produce a /rongly lum9\s %eet1 cov]+ an area ( m ?an "o squ>e metre1 :i* is a rem>kable effect ) ?is v small coil4 ,to avoid unc]ta9ty1 ! circle has be5 tak5 small]1 & ! area is n[ ab\t #j4dc squ>e metre4 ,! frequ5cy ( ! vibration1 & ! quickness ( succession ( ! sp>ks betwe5 ! knobs1 affect to a m>k$ degree ! appe>ance ( ! /reams4 ,:5 ! frequ5cy is v l[1 ! air gives way 9 m or less ! same mann]1 z by a /eady diff]5ce ( pot5tial1 & ! /reams consi/ ( di/9ct ?reads1 g5]ally m+l$ ) ?9 sp>ks1 :i* probably correspond to ! successive dis*>ges occurr+ betwe5 ! knobs4 ,b :5 ! frequ5cy is extremely high1 & ! arc ( ! dis*>ge produces a v l\d & smoo? s\nd--%[+ bo? t oscillation takes place & t ! sp>ks succe$ ea* o!r ) great rapidity--!n ! lum9\s /reams =m$ are p]fectly uni=m4 ,to rea* ?is result v small coils & j>s ( small capacity %\ld be us$4 ,i take two tubes ( ?ick ,bohemian glass1 ab\t #e c5timetres 9 diamet] & #bj c5timetres long4 ,9 ea* ( ! tubes ,i slip a prim>y ( v ?ick copp] wire4 ,on ! top ( ea* tube ,i w9d a second>y ( mu* ?9n] gutta-p]*a cov]$ wire4 ,! two second>ies ,i connect 9 s]ies1 ! prim>ies pref]ably 9 multiple arc4 ,! tubes are !n plac$ 9 a l>ge glass vessel1 at a di/ance ( #aj to #ae c5timetres f ea* o!r1 on insulat+ supports1 & ! vessel is fill$ ) boil$-out oil1 ! oil rea*+ ab\t an in* above ! tubes4 ,! free ends ( ! second>y are lift$ out ( ! coil & plac$ p>allel to ea* o!r at a di/ance ( ab\t t5 c5timetres4 ,! ends :i* are scrap$ %\ld be dipp$ 9 ! oil4 ,two f\r-p9t j>s jo9$ 9 s]ies may be us$ to dis*>ge ?r\gh ! prim>y4 ,:5 ! necess>y adju/m5ts 9 ! l5g? & di/ance ( ! wires above ! oil & 9 ! arc ( dis*>ge are made1 a lum9\s %eet is produc$ betwe5 ! wires :i* is p]fectly smoo? & textureless1 l ! ord9>y dis*>ge ?r\gh a mod]ately exhau/$ tube4 ,i h purposely dwelt ^u ?is app>5tly insignificant exp]im5t4 ,9 trials ( ?is k9d ! exp]im5t] arrives at ! />tl+ conclusion t1 to pass ord9>y lum9\s dis*>ges ?r\gh gases1 no p>ticul> degree ( exhau/ion is ne$$1 b t ! gas may be at ord9>y or ev5 great] pressure4 ,to accompli% ?is1 a v high frequ5cy is ess5tial2 a high pot5tial is likewise requir$1 b ?is is m]ely an incid5tal necessity4 ,^! exp]im5ts tea* u t1 9 endeavor+ to discov] novel me?ods ( produc+ light by ! agitation ( atoms1 or molecules1 ( a gas1 we ne$ n limit our rese>* to ! vacuum tube1 b may look =w>d q s]i\sly to ! possibility ( obta9+ ! light effects )\t ! use ( any vessel :atev]1 ) air at ord9>y pressure4 ,su* dis*>ges ( v high frequ5cy1 :i* r5d] lum9\s ! air at ord9>y pressures1 we h probably occasion (t5 to witness 9 ,nature4 ,i h no d\bt t if1 z _m believe1 ! aurora borealis is produc$ by sudd5 cosmic di/urbances1 su* z eruptions at ! sun's surface1 :i* set ! electro/atic *>ge ( ! e>? 9 an extremely rapid vibration1 ! r$ gl[ obs]v$ is n conf9$ to ! upp] r>efi$ /rata ( ! air1 b ! dis*>ge trav]ses1 by reason ( its v high frequ5cy1 also ! d5se atmosph]e 9 ! =m ( a gl[1 su* z we ord9>ily produce 9 a slightly exhau/$ tube4 ,if ! frequ5cy 7 v l[1 or ev5 m s1 if ! *>ge 7 n at all vibrat+1 ! d5se air w\ld break d[n z 9 a lightn+ dis*>ge4 ,indications ( su* break+ d[n ( ! l[] d5se /rata ( ! air h be5 repeat$ly obs]v$ at ! occurr5ce ( ?is m>vel\s ph5om5on2 b if x does occur1 x c only be attribut$ to ! fundam5tal di/urbances1 :i* are few 9 numb]1 = ! vibration produc$ by !m w\ld be f> too rapid to all[ a disruptive break4 ,x is ! orig9al & irregul> impulses :i* affect ! in/rum5ts2 ! sup]impos$ vibrations probably pass unnotic$4 ,:5 an ord9>y l[ frequ5cy dis*>ge is pass$ ?r\gh mod]ately r>efi$ air1 ! air assumes a purpli% hue4 ,if by "s means or o!r we increase ! int5sity ( ! molecul>1 or atomic1 vibration1 ! gas *anges to a :ite color4 ,a simil> *ange occurs at ord9>y pressures ) electric impulses ( v high frequ5cy4 ,if ! molecules ( ! air ar\nd a wire are mod]ately agitat$1 ! bru% =m$ is r$di% or violet2 if ! vibration is r5d]$ suffici5tly int5se1 ! /reams become :ite4 ,we may accompli% ?is 9 v>i\s ways4 ,9 ! exp]im5t be=e %[n ) ! two wires across ! room1 ,i h endeavor$ to secure ! result by pu%+ to a high value bo? ! frequ5cy & pot5tial2 9 ! exp]im5t ) ! ?9 wires glu$ on ! rubb] plate ,i h conc5trat$ ! action ^u a v small surface--9 o!r words1 ,i h work$ ) a great electric d5sity4 ,illu/ration3 ,,fig4 #adj4 ,a mo/ curi\s =m ( dis*>ge is obs]v$ ) su* a coil :5 ! frequ5cy & pot5tial are pu%$ to ! extreme limit4 ,to p]=m ! exp]im5t1 e "p ( ! coil %\ld be heavily insulat$1 & only two small sph]es--or1 bett] /ill1 two %>p-edg$ metal discs 7d d1 ,fig4 #adj7 ( no m ?an a few c5timetres 9 diamet]--%\ld be expos$ to ! air4 ,! coil "h us$ is imm]s$ 9 oil1 & ! ends ( ! second>y rea*+ out ( ! oil are cov]$ ) an air-tight cov] ( h>d rubb] ( great ?ickness4 ,all cracks1 if !re are any1 %\ld be c>efully /opp$ up1 s t ! bru% dis*>ge _c =m any:]e except on ! small sph]es or plates :i* are expos$ to ! air4 ,9 ?is case1 s9ce !re are no l>ge plates or o!r bodies ( capacity atta*$ to ! t]m9als1 ! coil is capable ( an extremely rapid vibration4 ,! pot5tial may be rais$ by increas+1 z f> z ! exp]im5t] judges prop]1 ! rate ( *ange ( ! prim>y curr5t4 ,) a coil n widely diff]+ f ! pres5t1 x is be/ to connect ! two prim>ies 9 multiple arc2 b if ! second>y %\ld h a mu* great] numb] ( turns ! prim>ies %\ld pref]ably be us$ 9 s]ies1 z o!rwise ! vibration might be too fa/ = ! second>y4 ,x occurs "u ^! conditions t mi/y :ite /reams break =? f ! edges ( ! discs & spread out phantom-l into space4 ,) ?is coil1 :5 fairly well produc$1 !y are ab\t #be to #cj c5timetres long4 ,:5 ! h& is held aga9/ !m no s5sation is produc$1 & a sp>k1 caus+ a %ock1 jumps f ! t]m9al only ^u ! h& be+ br\ght mu* ne>]4 ,if ! oscillation ( ! prim>y curr5t is r5d]$ int]mitt5t by "s means or o!r1 !re is a correspond+ ?robb+ ( ! /reams1 & n[ ! h& or o!r conduct+ object may be br\ght 9 /ill great] proximity to ! t]m9al )\t a sp>k be+ caus$ to jump4 ,among ! _m beautiful ph5om5a :i* may be produc$ ) su* a coil1 ,i h "h select$ only ^? :i* appe> to possess "s features ( novelty1 & lead u to "s conclusions ( int]e/4 ,"o w n f9d x at all difficult to produce 9 ! laboratory1 by means ( x1 _m o!r ph5om5a :i* appeal to ! eye ev5 m ?an ^! "h %[n1 b pres5t no p>ticul> feature ( novelty4 ,e>ly exp]im5t]s describe ! display ( sp>ks produc$ by an ord9>y l>ge induction coil ^u an insulat+ plate sep>at+ ! t]m9als4 ,q rec5tly ,siem5s p]=m$ "s exp]im5ts 9 :i* f9e effects 7 obta9$1 :i* 7 se5 by _m ) int]e/4 ,no d\bt l>ge coils1 ev5 if op]at$ ) curr5ts ( l[ frequ5cies1 are capable ( produc+ beautiful effects4 ,b ! l>ge/ coil ev] made c\ld n1 by f>1 equal ! magnific5t display ( /reams & sp>ks obta9$ f su* a disruptive dis*>ge coil :5 prop]ly adju/$4 ,to give an idea1 a coil su* z ! pres5t "o w cov] easily a plate ( "o metre 9 diamet] completely ) ! /reams4 ,! be/ way to p]=m su* exp]im5ts is to take a v ?9 rubb] or a glass plate & glue on "o side ( x a n>r[ r+ ( t9foil ( v l>ge diamet]1 & on ! o!r a circul> wa%]1 ! c5tre ( ! latt] co9cid+ ) t ( ! r+1 & ! surfaces ( bo? be+ pref]ably equal1 s z to keep ! coil well balanc$4 ,! wa%] & r+ %\ld be connect$ to ! t]m9als by heavily insulat$ ?9 wires4 ,x is easy 9 obs]v+ ! effect ( ! capacity to produce a %eet ( uni=m /reams1 or a f9e network ( ?9 silv]y ?reads1 or a mass ( l\d brilliant sp>ks1 :i* completely cov] ! plate4 ,s9ce ,i h advanc$ ! idea ( ! conv]sion by means ( ! disruptive dis*>ge1 9 my pap] be=e ! ,am]ican ,in/itute ( ,electrical ,eng9e]s at ! beg9n+ ( ! pa/ ye>1 ! int]e/ excit$ 9 x has be5 consid]able4 ,x af=ds u a means = produc+ any pot5tials by ! aid ( inexp5sive coils op]at$ f ord9>y sy/ems ( di/ribution1 &--:at is p]haps m appreciat$--x enables u to conv]t curr5ts ( any frequ5cy into curr5ts ( any o!r l[] or high] frequ5cy4 ,b its *ief value w p]haps be f\nd 9 ! help :i* x w af=d u 9 ! inve/igations ( ! ph5om5a ( phosphoresc5ce1 :i* a disruptive dis*>ge coil is capable ( excit+ 9 innum]able cases :]e ord9>y coils1 ev5 ! l>ge/1 w\ld utt]ly fail4 ,consid]+ its probable uses = _m practical purposes1 & its possible introduction into laboratories = sci5tific rese>*1 a few additional rem>ks z to ! con/ruction ( su* a coil w p]haps n be f\nd sup]flu\s4 ,x is1 ( c\rse1 absolutely necess>y to employ 9 su* a coil wires provid$ ) ! be/ insulation4 ,good coils may be produc$ by employ+ wires cov]$ ) sev]al lay]s ( cotton1 boil+ ! coil a long "t 9 pure wax1 & cool+ "u mod]ate pressure4 ,! advantage ( su* a coil is t x c be easily h&l$1 b x _c probably give z satisfactory results z a coil imm]s$ 9 pure oil4 ,besides1 x seems t ! pres5ce ( a l>ge body ( wax affects ! coil disadvantage\sly1 :]eas ?is does n seem to be ! case ) oil4 ,p]haps x is because ! dielectric losses 9 ! liquid are small]4 ,i h tri$ at fir/ silk & cotton cov]$ wires ) oil imm]sions1 b ,i h be5 gradually l$ to use gutta-p]*a cov]$ wires1 :i* prov$ mo/ satisfactory4 ,gutta-p]*a insulation adds1 ( c\rse1 to ! capacity ( ! coil1 & ?is1 especially if ! coil be l>ge1 is a great disadvantage :5 extreme frequ5cies are desir$2 b1 on ! o!r h&1 gutta-p]*a w )/& mu* m ?an an equal ?ickness ( oil1 & ?is advantage %\ld be secur$ at any price4 ,once ! coil has be5 imm]s$1 x %\ld nev] be tak5 out ( ! oil = m ?an a few h\rs1 else ! gutta-p]*a w crack up & ! coil w n be wor? half z mu* z be=e4 ,gutta-p]*a is probably sl[ly attack$ by ! oil1 b aft] an imm]sion ( eight to n9e mon?s ,i h f\nd no ill effects4 ,i h obta9$ two k9ds ( gutta-p]*a wire kn[n 9 comm]ce3 9 "o ! insulation /icks tightly to ! metal1 9 ! o!r x does n4 ,unless a special me?od is foll[$ to expel all air1 x is mu* saf] to use ! fir/ k9d4 ,i w9d ! coil )9 an oil tank s t all int]/ices are fill$ up ) ! oil4 ,betwe5 ! lay]s ,i use clo? boil$ out ?or\ghly 9 oil1 calculat+ ! ?ickness accord+ to ! diff]5ce ( pot5tial betwe5 ! turns4 ,!re seems n to be a v great diff]5ce :atev] k9d ( oil is us$2 ,i use p>aff9e or l9se$ oil4 ,to exclude m p]fectly ! air1 an excell5t way to proce$1 & easily practicable ) small coils1 is ! foll[+3 ,con/ruct a box ( h>dwood ( v ?ick bo>ds :i* h be5 = a long "t boil$ 9 oil4 ,! bo>ds %\ld be s jo9$ z to safely )/& ! ext]nal air pressure4 ,! coil be+ plac$ & fa/5$ 9 position )9 ! box1 ! latt] is clos$ ) a /rong lid1 & cov]$ ) closely fitt+ metal %eets1 ! jo9ts ( :i* are sold]$ v c>efully4 ,on ! top two small holes are drill$1 pass+ ?r\gh ! metal %eet & ! wood1 & 9 ^! holes two small glass tubes are ins]t$ & ! jo9ts made air-tight4 ,"o ( ! tubes is connect$ to a vacuum pump1 & ! o!r ) a vessel conta9+ a suffici5t quantity ( boil$-out oil4 ,! latt] tube has a v small hole at ! bottom1 & is provid$ ) a /opcock4 ,:5 a fairly good vacuum has be5 obta9$1 ! /opcock is op5$ & ! oil sl[ly f$ 94 ,proce$+ 9 ?is mann]1 x is impossible t any big bubbles1 :i* are ! pr9cipal dang]1 %\ld rema9 betwe5 ! turns4 ,! air is mo/ completely exclud$1 probably bett] ?an by boil+ out1 :i*1 h[ev]1 :5 gutta-p]*a coat$ wires are us$1 is n practicable4 ,= ! prim>ies ,i use ord9>y l9e wire ) a ?ick cotton coat+4 ,/r&s ( v ?9 insulat$ wires prop]ly int]lac$ w\ld1 ( c\rse1 be ! be/ to employ = ! prim>ies1 b !y are n to be _h4 ,9 an exp]im5tal coil ! size ( ! wires is n ( great importance4 ,9 ! coil "h us$ ! prim>y is ,no4 #ab & ! second>y ,no4 #bd ,br[n ,%>pe gauge wire2 b ! sections may be v>i$ consid]ably4 ,x w\ld only imply diff]5t adju/m5ts2 ! results aim$ at w\ld n be mat]ially affect$4 ,i h dwelt at "s l5g? ^u ! v>i\s =ms ( bru% dis*>ge because1 9 /udy+ !m1 we n only obs]ve ph5om5a :i* please our eye1 b also af=d u food = ?\ght1 & lead u to conclusions ( practical importance4 ,9 ! use ( alt]nat+ curr5ts ( v high t5sion1 too mu* precaution _c be tak5 to prev5t ! bru% dis*>ge4 ,9 a ma9 convey+ su* curr5ts1 9 an induction coil or trans=m]1 or 9 a cond5s]1 ! bru% dis*>ge is a s\rce ( great dang] to ! insulation4 ,9 a cond5s]1 especially1 ! gase\s matt] mu/ be mo/ c>efully expell$1 = 9 x ! *>g$ surfaces are ne> ea* o!r1 & if ! pot5tials are high1 j z sure z a weight w fall if let g1 s ! insulation w give way if a s+le gase\s bubble ( "s size be pres5t1 :]eas1 if all gase\s matt] 7 c>efully exclud$1 ! cond5s] w\ld safely )/& a mu* high] diff]5ce ( pot5tial4 ,a ma9 convey+ alt]nat+ curr5ts ( v high t5sion may be injur$ m]ely by a bl[ hole or small crack 9 ! insulation1 ! m s z a bl[hole is apt to conta9 gas at l[ pressure2 & z x appe>s almo/ impossible to completely obviate su* little imp]fections1 ,i am l$ to believe t 9 our future di/ribution ( electrical en]gy by curr5ts ( v high t5sion1 liquid insulation w be us$4 ,! co/ is a great drawback1 b if we employ an oil z an insulator ! di/ribution ( electrical en]gy ) some?+ l #ajj1jjj volts1 & ev5 m1 becomes1 at lea/ ) high] frequ5cies1 s easy t x c\ld be h>dly call$ an eng9e]+ feat4 ,) oil insulation & alt]nate curr5t motors1 transmissions ( p[] c be affect$ ) safety & ^u an indu/rial basis at di/ances ( z mu* z a ?\s& miles4 ,a peculi> prop]ty ( oils1 & liquid insulation 9 g5]al1 :5 subject$ to rapidly *ang+ electric /resses1 is to disp]se any gase\s bubbles :i* may be pres5t1 & diffuse !m ?r\gh its mass1 g5]ally long be=e any injuri\s break c occur4 ,?is feature may be easily obs]v$ ) an ord9>y induction coil by tak+ ! prim>y out1 plugg+ up ! end ( ! tube ^u :i* ! second>y is w\nd1 & fill+ x ) "s fairly transp>5t insulator1 su* z p>aff9e oil4 ,a prim>y ( a diamet] some?+ l six millimetres small] ?an ! inside ( ! tube may be ins]t$ 9 ! oil4 ,:5 ! coil is set to "w "o may see1 look+ f ! top ?r\gh ! oil1 _m lum9\s po9ts--air bubbles :i* are caught by ins]t+ ! prim>y1 & :i* are r5d]$ lum9\s 9 consequ5ce ( ! viol5t bomb>dm5t4 ,! occlud$ air1 by its impact aga9/ ! oil1 heats x2 ! oil beg9s to circulate1 c>ry+ "s ( ! air along ) x1 until ! bubbles are disp]s$ & ! lum9\s po9ts disappe>4 ,9 ?is mann]1 unless l>ge bubbles are occlud$ 9 su* way t circulation is r5d]$ impossible1 a damag+ break is av]t$1 ! only effect be+ a mod]ate w>m+ up ( ! oil4 ,if1 in/ead ( ! liquid1 a solid insulation1 no matt] h[ ?ick1 7 us$1 a break+ ?r\gh & injury ( ! app>atus w\ld be inevitable4 ,! exclusion ( gase\s matt] f any app>atus 9 :i* ! dielectric is subject$ to m or less rapidly *ang+ electric =ces is1 h[ev]1 n only desirable 9 ord] to avoid a possible injury ( ! app>atus1 b also on acc\nt ( economy4 ,9 a cond5s]1 = in/ance1 z long z only a solid or only a liquid dielectric is us$1 ! loss is small2 b if a gas "u ord9>y or small pressure be pres5t ! loss may be v great4 ,:atev] ! nature ( ! =ce act+ 9 ! dielectric may be1 x seems t 9 a solid or liquid ! molecul> displacem5t produc$ by ! =ce is small3 h5ce ! product ( =ce & displacem5t is insignificant1 unless ! =ce be v great2 b 9 a gas ! displacem5t1 & !re=e ?is product1 is consid]able2 ! molecules are free to move1 !y rea* high spe$s1 & ! en]gy ( _! impact is lo/ 9 heat or o!rwise4 ,if ! gas be /rongly compress$1 ! displacem5t due to ! =ce is made small]1 & ! losses are r$uc$4 ,9 mo/ ( ! succe$+ exp]im5ts ,i pref]1 *iefly on acc\nt ( ! regul> & positive action1 to employ ! alt]nator be=e ref]r$ to4 ,?is is "o ( ! sev]al ma*9es con/ruct$ by me = ! purpose ( ^! inve/igations4 ,x has #chd pole projections1 & is capable ( giv+ curr5ts ( a frequ5cy ( ab\t #aj1jjj p] second4 ,?is ma*9e has be5 illu/rat$ & briefly describ$ 9 my fir/ pap] be=e ! ,am]ican ,in/itute ( ,electrical ,eng9e]s1 ,may #bj?1 #ahia1 to :i* ,i h already ref]r$4 ,a m detail$ description1 suffici5t to enable any eng9e] to build a simil> ma*9e1 w be f\nd 9 sev]al electrical j\rnals ( t p]iod4 ,! induction coils op]at$ f ! ma*9e are r small1 conta9+ f #e1jjj to #ae1jjj turns 9 ! second>y4 ,!y are imm]s$ 9 boil$-out l9se$ oil1 conta9$ 9 wood5 boxes cov]$ ) z9c %eet4 ,i h f\nd x advantage\s to rev]se ! usual position ( ! wires1 & to w9d1 9 ^! coils1 ! prim>ies on ! top2 ?us all[+ ! use ( a mu* l>g] prim>y1 :i*1 ( c\rse1 r$uces ! dang] ( ov]heat+ & increases ! output ( ! coil4 ,i make ! prim>y on ea* side at lea/ "o c5timetre %ort] ?an ! second>y1 to prev5t ! break+ ?r\gh on ! ends1 :i* w\ld surely occur unless ! insulation on ! top ( ! second>y be v ?ick1 & ?is1 ( c\rse1 w\ld be disadvantage\s4 ,:5 ! prim>y is made movable1 :i* is necess>y 9 "s exp]im5ts1 & _m times conv5i5t = ! purposes ( adju/m5t1 ,i cov] ! second>y ) wax1 & turn x (f 9 a la! to a diamet] slightly small] ?an ! inside ( ! prim>y coil4 ,! latt] ,i provide ) a h&le rea*+ out ( ! oil1 :i* s]ves to %ift x 9 any position along ! second>y4 ,i w n[ v5ture to make1 9 reg>d to ! g5]al manipulation ( induction coils1 a few obs]vations be>+ ^u po9ts :i* h n be5 fully appreciat$ 9 e>li] exp]im5ts ) su* coils1 & are ev5 n[ (t5 ov]look$4 ,! second>y ( ! coil possesses usually su* a high self-induction t ! curr5t ?r\gh ! wire is inappreciable1 & may be s ev5 :5 ! t]m9als are jo9$ by a conductor ( small resi/ance4 ,if capacity is add$ to ! t]m9als1 ! self-induction is c\nt]act$1 & a /rong] curr5t is made to fl[ ?r\gh ! second>y1 ?\gh its t]m9als are insulat$ f ea* o!r4 ,to "o entirely unacqua9t$ ) ! prop]ties ( alt]nat+ curr5ts no?+ w look m puzzl+4 ,?is feature 0 illu/rat$ 9 ! exp]im5t p]=m$ at ! beg9n+ ) ! top plates ( wire gauze atta*$ to ! t]m9als & ! rubb] plate4 ,:5 ! plates ( wire gauze 7 close toge!r1 & a small arc pass$ betwe5 !m1 ! arc prev5t$ a /rong curr5t f pass+ ?r\gh ! second>y1 because x did away ) ! capacity on ! t]m9als2 :5 ! rubb] plate 0 ins]t$ betwe51 ! capacity ( ! cond5s] =m$ c\nt]act$ ! self-induction ( ! second>y1 a /rong] curr5t pass$ n[1 ! coil p]=m$ m "w1 & ! dis*>ge 0 by f> m p[]ful4 ,! fir/ ?+1 !n1 9 op]at+ ! induction coil is to comb9e capacity ) ! second>y to ov]come ! self-induction4 ,if ! frequ5cies & pot5tials are v high1 gase\s matt] %\ld be c>efully kept away f ! *>g$ surfaces4 ,if ,leyd5 j>s are us$1 !y %\ld be imm]s$ 9 oil1 z o!rwise consid]able dissipation may occur if ! j>s are greatly /ra9$4 ,:5 high frequ5cies are us$1 x is ( equal importance to comb9e a cond5s] ) ! prim>y4 ,"o may use a cond5s] connect$ to ! ends ( ! prim>y or to ! t]m9als ( ! alt]nator1 b ! latt] is n to be recomm5d$1 z ! ma*9e might be injur$4 ,! be/ way is und\bt$ly to use ! cond5s] 9 s]ies ) ! prim>y & ) ! alt]nator1 & to adju/ its capacity s z to annul ! self-induction ( bo? ! latt]4 ,! cond5s] %\ld be adju/able by v small /eps1 & = a f9] adju/m5t a small oil cond5s] ) movable plates may be us$ conv5i5tly4 ,i ?9k x be/ at ?is juncture to br+ be=e y a ph5om5on1 obs]v$ by me "s "t ago1 :i* to ! purely sci5tific inve/igator may p]haps appe> m int]e/+ ?an any ( ! results :i* ,i h ! privilege to pres5t to y ?is ev5+4 ,x may be q prop]ly rank$ among ! bru% ph5om5a--9 fact1 x is a bru%1 =m$ at1 or ne>1 a s+le t]m9al 9 high vacuum4 ,illu/ration3 ,,fig4 #ada4 ,illu/ration3 ,,fig4 #adb4 ,9 bulbs provid$ ) a conduct+ t]m9al1 ?\gh x be ( alum9um1 ! bru% has b an ephem]al exi/5ce1 & _c1 un=tunately1 be indef9itely pres]v$ 9 its mo/ s5sitive /ate1 ev5 9 a bulb devoid ( any conduct+ electrode4 ,9 /udy+ ! ph5om5on1 by all means a bulb hav+ no lead+-9 wire %\ld be us$4 ,i h f\nd x be/ to use bulbs con/ruct$ z indicat$ 9 ,figs4 #ada & #adb4 ,9 ,fig4 #ada ! bulb comprises an inc&esc5t lamp globe ,l1 9 ! neck ( :i* is seal$ a b>omet] tube b1 ! end ( :i* is bl[n out to =m a small sph]e s4 ,?is sph]e %\ld be seal$ z closely z possible 9 ! c5tre ( ! l>ge globe4 ,be=e seal+1 a ?9 tube t1 ( alum9um %eet1 may be slipp$ 9 ! b>omet] tube1 b x is n important to employ x4 ,! small holl[ sph]e s is fill$ ) "s conduct+ p[d]1 & a wire w is cem5t$ 9 ! neck = ! purpose ( connect+ ! conduct+ p[d] ) ! g5]ator4 ,! con/ruction %[n 9 ,fig4 #adb 0 *os5 9 ord] to remove f ! bru% any conduct+ body :i* might possibly affect x4 ,! bulb consi/s 9 ?is case ( a lamp globe ,l1 :i* has a neck n1 provid$ ) a tube b & small sph]e s1 seal$ to x1 s t two entirely indep5d5t comp>tm5ts are =m$1 z indicat$ 9 ! draw+4 ,:5 ! bulb is 9 use ! neck n is provid$ ) a t9foil coat+1 :i* is connect$ to ! g5]ator & acts inductively ^u ! mod]ately r>efi$ & highly conduct$ gas inclos$ 9 ! neck4 ,f !re ! curr5t passes ?r\gh ! tube b into ! small sph]e s1 to act by induction ^u ! gas conta9$ 9 ! globe ,l4 ,x is ( advantage to make ! tube t v ?ick1 ! hole ?r\gh x v small1 & to bl[ ! sph]e s v ?94 ,x is ( ! greate/ importance t ! sph]e s be plac$ 9 ! c5tre ( ! globe ,l4 ,illu/ration3 ,,fig4 #adc4 ,figs4 #adc1 #add & #ade indicate diff]5t =ms1 or /ages1 ( ! bru%4 ,fig4 #adc %[s ! bru% z x fir/ appe>s 9 a bulb provid$ ) a conduct+ t]m9al2 b1 z 9 su* a bulb x v soon disappe>s--(t5 aft] a few m9utes--,i w conf9e myself to ! description ( ! ph5om5on z se5 9 a bulb )\t conduct+ electrode4 ,x is obs]v$ "u ! foll[+ conditions3 ,:5 ! globe ,l 7,figs4 #ada & #adb7 is exhau/$ to a v high degree1 g5]ally ! bulb is n excit$ ^u connect+ ! wire w 7,fig4 #ada7 or ! t9foil coat+ ( ! bulb 7,fig4 #adb7 to ! t]m9al ( ! induction coil4 ,to excite x1 x is usually suffici5t to grasp ! globe ,l ) ! h&4 ,an int5se phosphoresc5ce !n spreads at fir/ ov] ! globe1 b soon gives place to a :ite1 mi/y light4 ,%ortly aft]w>d "o may notice t ! lum9osity is unev5ly di/ribut$ 9 ! globe1 & aft] pass+ ! curr5t = "s "t ! bulb appe>s z 9 ,fig4 #add4 ,f ?is /age ! ph5om5on w gradually pass to t indicat$ 9 ,fig4 #ade1 aft] "s m9utes1 h\rs1 days or weeks1 accord+ z ! bulb is work$4 ,w>m+ ! bulb or increas+ ! pot5tial ha/5s ! transit4 ,illu/ration3 ,,fig4 #add4 ,illu/ration3 ,,fig4 #ade4 ,:5 ! bru% assumes ! =m indicat$ 9 ,fig4 #ade1 x may be br\ght to a /ate ( extreme s5sitiv5ess to electro/atic & magnetic influ5ce4 ,! bulb hang+ /raight d[n f a wire1 & all objects be+ remote f x1 ! approa* ( ! obs]v] at a few paces f ! bulb w cause ! bru% to fly to ! opposite side1 & if he walks ar\nd ! bulb x w always keep on ! opposite side4 ,x may beg9 to sp9 ar\nd ! t]m9al long be=e x rea*es t s5sitive /age4 ,:5 x beg9s to turn ar\nd1 pr9cipally1 b also be=e1 x is affect$ by a magnet1 & at a c]ta9 /age x is susceptible to magnetic influ5ce to an a/oni%+ degree4 ,a small p]man5t magnet1 ) its poles at a di/ance ( no m ?an two c5timetres1 w affect x visibly at a di/ance ( two metres1 sl[+ d[n or accel]at+ ! rotation accord+ to h[ x is held relatively to ! bru%4 ,i ?9k ,i h obs]v$ t at ! /age :5 x is mo/ s5sitive to magnetic1 x is n mo/ s5sitive to electro/atic1 influ5ce4 ,my explanation is1 t ! electro/atic attraction betwe5 ! bru% & ! glass ( ! bulb1 :i* ret>ds ! rotation1 gr[s mu* quick] ?an ! magnetic influ5ce :5 ! int5sity ( ! /ream is increas$4 ,:5 ! bulb hangs ) ! globe ,l d[n1 ! rotation is always clockwise4 ,9 ! s\!rn hemisph]e x w\ld occur 9 ! opposite direction & on ! equator ! bru% %\ld n turn at all4 ,! rotation may be rev]s$ by a magnet kept at "s di/ance4 ,! bru% rotates be/1 seem+ly1 :5 x is at "r angles to ! l9es ( =ce ( ! e>?4 ,x v likely rotates1 :5 at its maximum spe$1 9 syn*ronism ) ! alt]nations1 say1 #aj1jjj times a second4 ,! rotation c be sl[$ d[n or accel]at$ by ! approa* or rec$+ ( ! obs]v]1 or any conduct+ body1 b x _c be rev]s$ by putt+ ! bulb 9 any position4 ,:5 x is 9 ! /ate ( ! highe/ s5sitiv5ess & ! pot5tial or frequ5cy be v>i$1 ! s5sitiv5ess is rapidly dim9i%$4 ,*ang+ ei!r ( ^! b little w g5]ally /op ! rotation4 ,! s5sitiv5ess is likewise affect$ by ! v>iations ( temp]ature4 ,to atta9 great s5sitiv5ess x is necess>y to h ! small sph]e s 9 ! c5tre ( ! globe ,l1 z o!rwise ! electro/atic action ( ! glass ( ! globe w t5d to /op ! rotation4 ,! sph]e s %\ld be small & ( uni=m ?ickness2 any dissymmetry ( c\rse has ! effect to dim9i% ! s5sitiv5ess4 ,! fact t ! bru% rotates 9 a def9ite direction 9 a p]man5t magnetic field seems to %[ t 9 alt]nat+ curr5ts ( v high frequ5cy ! positive & negative impulses are n equal1 b t "o always prepond]ates ov] ! o!r4 ,( c\rse1 ?is rotation 9 "o direction may be due to ! action ( ! two elem5ts ( ! same curr5t ^u ea* o!r1 or to ! action ( ! field produc$ by "o ( ! elem5ts ^u ! o!r1 z 9 a s]ies motor1 )\t necess>ily "o impulse be+ /rong] ?an ! o!r4 ,! fact t ! bru% turns1 z f> z ,i c\ld obs]ve1 9 any position1 w\ld speak = ?is view4 ,9 su* case x w\ld turn at any po9t ( ! e>?'s surface4 ,b1 on ! o!r h&1 x is !n h>d to expla9 :y a p]man5t magnet %\ld rev]se ! rotation1 & "o mu/ assume ! prepond]ance ( impulses ( "o k9d4 ,z to ! causes ( ! =mation ( ! bru% or /ream1 ,i ?9k x is due to ! electro/atic action ( ! globe & ! dissymmetry ( ! p>ts4 ,if ! small bulb s & ! globe ,l 7 p]fect conc5tric sph]es1 & ! glass ?r\gh\t ( ! same ?ickness & quality1 ,i ?9k ! bru% w\ld n =m1 z ! t5d5cy to pass w\ld be equal on all sides4 ,t ! =mation ( ! /ream is due to an irregul>ity is app>5t f ! fact t x has ! t5d5cy to rema9 9 "o position1 & rotation occurs mo/ g5]ally only :5 x is br\ght out ( ?is position by electro/atic or magnetic influ5ce4 ,:5 9 an extremely s5sitive /ate x re/s 9 "o position1 mo/ curi\s exp]im5ts may be p]=m$ ) x4 ,= in/ance1 ! exp]im5t] may1 by select+ a prop] position1 approa* ! h& at a c]ta9 consid]able di/ance to ! bulb1 & he may cause ! bru% to pass (f by m]ely /iff5+ ! muscles ( ! arm4 ,:5 x beg9s to rotate sl[ly1 & ! h&s are held at a prop] di/ance1 x is impossible to make ev5 ! slighte/ motion )\t produc+ a visible effect ^u ! bru%4 ,a metal plate connect$ to ! o!r t]m9al ( ! coil affects x at a great di/ance1 sl[+ d[n ! rotation (t5 to "o turn a second4 ,i am firmly conv9c$ t su* a bru%1 :5 we le>n h[ to produce x prop]ly1 w prove a valuable aid 9 ! inve/igation ( ! nature ( ! =ces act+ 9 an electro/atic or magnetic field4 ,if !re is any motion :i* is measurable go+ on 9 ! space1 su* a bru% ought to reveal x4 ,x is1 s to speak1 a beam ( light1 frictionless1 devoid ( in]tia4 ,i ?9k t x may f9d practical applications 9 telegraphy4 ,) su* a bru% x w\ld be possible to s5d dispat*es across ! ,atlantic1 = in/ance1 ) any spe$1 s9ce its s5sitiv5ess may be s great t ! slighte/ *anges w affect x4 ,if x 7 possible to make ! /ream m int5se & v n>r[1 its deflections c\ld be easily photograph$4 ,i h be5 int]e/$ to f9d :e!r !re is a rotation ( ! /ream itself1 or :e!r !re is simply a /ress travel+ ar\nd ! bulb4 ,= ?is purpose ,i m\nt$ a light mica fan s t its vanes 7 9 ! pa? ( ! bru%4 ,if ! /ream itself 0 rotat+ ! fan w\ld be spun ar\nd4 ,i c\ld produce no di/9ct rotation ( ! fan1 al?\gh ,i tri$ ! exp]im5t repeat$ly2 b z ! fan ex]t$ a noticeable influ5ce on ! /ream1 & ! app>5t rotation ( ! latt] 01 9 ?is case1 nev] q satisfactory1 ! exp]im5t did n appe> to be conclusive4 ,i h be5 unable to produce ! ph5om5on ) ! disruptive dis*>ge coil1 al?\gh e o!r ( ^! ph5om5a c be well produc$ by x--_m1 9 fact1 mu* bett] ?an ) coils op]at$ f an alt]nator4 ,x may be possible to produce ! bru% by impulses ( "o direction1 or ev5 by a /eady pot5tial1 9 :i* case x w\ld be /ill m s5sitive to magnetic influ5ce4 ,9 op]at+ an induction coil ) rapidly alt]nat+ curr5ts1 we realize ) a/oni%m5t1 = ! fir/ "t1 ! great importance ( ! relation ( capacity1 self-induction & frequ5cy z reg>ds ! g5]al results4 ,! effects ( capacity are ! mo/ /rik+1 = 9 ^! exp]im5ts1 s9ce ! self-induction & frequ5cy bo? are high1 ! critical capacity is v small1 & ne$ be b slightly v>i$ to produce a v consid]able *ange4 ,! exp]im5t] may br+ 8 body 9 contact ) ! t]m9als ( ! second>y ( ! coil1 or atta* to "o or bo? t]m9als insulat$ bodies ( v small bulk1 su* z bulbs1 & he may produce a consid]able rise or fall ( pot5tial1 & greatly affect ! fl[ ( ! curr5t ?r\gh ! prim>y4 ,9 ! exp]im5t be=e %[n1 9 :i* a bru% appe>s at a wire atta*$ to "o t]m9al1 & ! wire is vibrat$ :5 ! exp]im5t] br+s 8 insulat$ body 9 contact ) ! o!r t]m9al ( ! coil1 ! sudd5 rise ( pot5tial 0 made evid5t4 ,i may %[ y ! behavior ( ! coil 9 ano!r mann] :i* possesses a feature ( "s int]e/4 ,i h "h a little light fan ( alum9um %eet1 fa/5$ to a ne$le & arrang$ to rotate freely 9 a metal piece screw$ to "o ( ! t]m9als ( ! coil4 ,:5 ! coil is set to "w1 ! molecules ( ! air are rhy?mically attract$ & repell$4 ,z ! =ce ) :i* !y are repell$ is great] ?an t ) :i* !y are attract$1 x results t !re is a repulsion ex]t$ on ! surfaces ( ! fan4 ,if ! fan 7 made simply ( a metal %eet1 ! repulsion w\ld be equal on ! opposite sides1 & w\ld produce no effect4 ,b if "o ( ! oppos+ surfaces is scre5$1 or if1 g5]ally speak+1 ! bomb>dm5t on ?is side is weak5$ 9 "s way or o!r1 !re rema9s ! repulsion ex]t$ ^u ! o!r1 & ! fan is set 9 rotation4 ,! scre5+ is be/ effect$ by fa/5+ ^u "o ( ! oppos+ sides ( ! fan insulat$ conduct+ coat+s1 or1 if ! fan is made 9 ! %ape ( an ord9>y propell] screw1 by fa/5+ on "o side1 & close to x1 an insulat$ metal plate4 ,! /atic scre5 may1 h[ev]1 be omitt$1 & simply a ?ickness ( insulat+ mat]ial fa/5$ to "o ( ! sides ( ! fan4 ,to %[ ! behavior ( ! coil1 ! fan may be plac$ ^u ! t]m9al & x w readily rotate :5 ! coil is op]at$ by curr5ts ( v high frequ5cy4 ,) a /eady pot5tial1 ( c\rse1 & ev5 ) alt]nat+ curr5ts ( v l[ frequ5cy1 x w\ld n turn1 because ( ! v sl[ ex*ange ( air &1 consequ5tly1 small] bomb>dm5t2 b 9 ! latt] case x might turn if ! pot5tial 7 excessive4 ,) a p9 :eel1 q ! opposite rule holds good2 x rotates be/ ) a /eady pot5tial1 & ! ef=t is ! small] ! high] ! frequ5cy4 ,n[1 x is v easy to adju/ ! conditions s t ! pot5tial is normally n suffici5t to turn ! fan1 b t by connect+ ! o!r t]m9al ( ! coil ) an insulat$ body x rises to a mu* great] value1 s z to rotate ! fan1 & x is likewise possible to /op ! rotation by connect+ to ! t]m9al a body ( diff]5t size1 !reby dim9i%+ ! pot5tial4 ,in/ead ( us+ ! fan 9 ?is exp]im5t1 we may use ! electric radiomet] ) simil> effect4 ,b 9 ?is case x w be f\nd t ! vanes w rotate only at high exhau/ion or at ord9>y pressures2 !y w n rotate at mod]ate pressures1 :5 ! air is highly conduct+4 ,?is curi\s obs]vation 0 made conjo9tly by ,pr(essor ,crookes & myself4 ,i attribute ! result to ! high conductivity ( ! air1 ! molecules ( :i* !n d n act z indep5d5t c>ri]s ( electric *>ges1 b act all toge!r z a s+le conduct+ body4 ,9 su* case1 ( c\rse1 if !re is any repulsion at all ( ! molecules f ! vanes1 x mu/ be v small4 ,x is possible1 h[ev]1 t ! result is 9 "p due to ! fact t ! great] "p ( ! dis*>ge passes f ! lead+-9 wire ?r\gh ! highly conduct+ gas1 in/ead ( pass+ (f f ! conduct+ vanes4 ,9 try+ ! prec$+ exp]im5t ) ! electric radiomet] ! pot5tial %\ld n exce$ a c]ta9 limit1 z !n ! electro/atic attraction betwe5 ! vanes & ! glass ( ! bulb may be s great z to /op ! rotation4 ,a mo/ curi\s feature ( alt]nate curr5ts ( high frequ5cies & pot5tials is t !y enable u to p]=m _m exp]im5ts by ! use ( "o wire only4 ,9 _m respects ?is feature is ( great int]e/4 ,9 a type ( alt]nate curr5t motor inv5t$ by me "s ye>s ago ,i produc$ rotation by induc+1 by means ( a s+le alt]nat+ curr5t pass$ ?r\gh a motor circuit1 9 ! mass or o!r circuits ( ! motor1 second>y curr5ts1 :i*1 jo9tly ) ! prim>y or induc+ curr5t1 creat$ a mov+ field ( =ce4 ,a simple b crude =m ( su* a motor is obta9$ by w9d+ ^u an iron core a prim>y1 & close to x a second>y coil1 jo9+ ! ends ( ! latt] & plac+ a freely movable metal disc )9 ! influ5ce ( ! field produc$ by bo?4 ,! iron core is employ$ = obvi\s reasons1 b x is n ess5tial to ! op]ation4 ,to improve ! motor1 ! iron core is made to encircle ! armature4 ,aga9 to improve1 ! second>y coil is made to p>tly ov]lap ! prim>y1 s t x _c free itself f a /rong inductive action ( ! latt]1 repel its l9es z x may4 ,once m to improve1 ! prop] diff]5ce ( phase is obta9$ betwe5 ! prim>y & second>y curr5ts by a cond5s]1 self-induction1 resi/ance or equival5t w9d+s4 ,i _h discov]$1 h[ev]1 t rotation is produc$ by means ( a s+le coil & core2 my explanation ( ! ph5om5on1 & lead+ ?\ght 9 try+ ! exp]im5t1 be+ t !re mu/ be a true "t lag 9 ! magnetization ( ! core4 ,i rememb] ! pleasure ,i _h :51 9 ! writ+s ( ,pr(essor ,ayrton1 :i* came lat] to my h&1 ,i f\nd ! idea ( ! "t lag advocat$4 ,:e!r !re is a true "t lag1 or :e!r ! ret>dation is due to eddy curr5ts circulat+ 9 m9ute pa?s1 mu/ rema9 an op5 "q1 b ! fact is t a coil w\nd ^u an iron core & trav]s$ by an alt]nat+ curr5t creates a mov+ field ( =ce1 capable ( sett+ an armature 9 rotation4 ,x is ( "s int]e/1 9 conjunction ) ! hi/orical ,arago exp]im5t1 to m5tion t 9 lag or phase motors ,i h produc$ rotation 9 ! opposite direction to ! mov+ field1 :i* means t 9 t exp]im5t ! magnet may n rotate1 or may ev5 rotate 9 ! opposite direction to ! mov+ disc4 ,"h1 !n1 is a motor 7diagrammatically illu/rat$ 9 ,fig4 #adf71 compris+ a coil & iron core1 & a freely movable copp] disc 9 proximity to ! latt]4 ,illu/ration3 ,,fig4 #adf4 ,to demon/rate a novel & int]e/+ feature1 ,i h1 = a reason :i* ,i w expla91 select$ ?is type ( motor4 ,:5 ! ends ( ! coil are connect$ to ! t]m9als ( an alt]nator ! disc is set 9 rotation4 ,b x is n ?is exp]im5t1 n[ well kn[n1 :i* ,i desire to p]=m4 ,:at ,i wi% to %[ y is t ?is motor rotates ) "o s+le connection betwe5 x & ! g5]ator2 t is to say1 "o t]m9al ( ! motor is connect$ to "o t]m9al ( ! g5]ator--9 ?is case ! second>y ( a high-t5sion induction coil--! o!r t]m9als ( motor & g5]ator be+ insulat$ 9 space4 ,to produce rotation x is g5]ally 7b n absolutely7 necess>y to connect ! free end ( ! motor coil to an insulat$ body ( "s size4 ,! exp]im5t]'s body is m ?an suffici5t4 ,if he t\*es ! free t]m9al ) an object held 9 ! h&1 a curr5t passes ?r\gh ! coil & ! copp] disc is set 9 rotation4 ,if an exhau/$ tube is put 9 s]ies ) ! coil1 ! tube lights brilliantly1 %[+ ! passage ( a /rong curr5t4 ,in/ead ( ! exp]im5t]'s body1 a small metal %eet susp5d$ on a cord may be us$ ) ! same result4 ,9 ?is case ! plate acts z a cond5s] 9 s]ies ) ! coil4 ,x c\nt]acts ! self-induction ( ! latt] & all[s a /rong curr5t to pass4 ,9 su* a comb9ation1 ! great] ! self-induction ( ! coil ! small] ne$ be ! plate1 & ?is means t a l[] frequ5cy1 or ev5tually a l[] pot5tial1 is requir$ to op]ate ! motor4 ,a s+le coil w\nd ^u a core has a high self-induction2 = ?is reason1 pr9cipally1 ?is type ( motor 0 *os5 to p]=m ! exp]im5t4 ,7 a second>y clos$ coil w\nd ^u ! core1 x w\ld t5d to dim9i% ! self-induction1 & !n x w\ld be necess>y to employ a mu* high] frequ5cy & pot5tial4 ,nei!r w\ld be advisable1 = a high] pot5tial w\ld endang] ! insulation ( ! small prim>y coil1 & a high] frequ5cy w\ld result 9 a mat]ially dim9i%$ torque4 ,x %\ld be rem>k$ t :5 su* a motor ) a clos$ second>y is us$1 x is n at all easy to obta9 rotation ) excessive frequ5cies1 z ! second>y cuts (f almo/ completely ! l9es ( ! prim>y--& ?is1 ( c\rse1 ! m1 ! high] ! frequ5cy--& all[s ! passage ( b a m9ute curr5t4 ,9 su* a case1 unless ! second>y is clos$ ?r\gh a cond5s]1 x is almo/ ess5tial1 9 ord] to produce rotation1 to make ! prim>y & second>y coils ov]lap ea* o!r m or less4 ,b !re is an additional feature ( int]e/ ab\t ?is motor1 namely1 x is n necess>y to h ev5 a s+le connection betwe5 ! motor & g5]ator1 except1 p]haps1 ?r\gh ! gr\nd2 = n only is an insulat$ plate capable ( giv+ (f en]gy into space1 b x is likewise capable ( d]iv+ x f an alt]nat+ electro/atic field1 ?\gh 9 ! latt] case ! available en]gy is mu* small]4 ,9 ?is in/ance "o ( ! motor t]m9als is connect$ to ! insulat$ plate or body locat$ )9 ! alt]nat+ electro/atic field1 & ! o!r t]m9al pref]ably to ! gr\nd4 ,x is q possible1 h[ev]1 t su* no wire motors1 z !y might be call$1 c\ld be op]at$ by conduction ?r\gh ! r>efi$ air at consid]able di/ances4 ,alt]nate curr5ts1 especially ( high frequ5cies1 pass ) a/oni%+ fre$om ?r\gh ev5 slightly r>efi$ gases4 ,! upp] /rata ( ! air are r>efi$4 ,to rea* a numb] ( miles out into space requires ! ov]com+ ( difficulties ( a m]ely me*anical nature4 ,!re is no d\bt t ) ! enorm\s pot5tials obta9able by ! use ( high frequ5cies & oil insulation1 lum9\s dis*>ges might be pass$ ?r\gh _m miles ( r>efi$ air1 & t1 by ?us direct+ ! en]gy ( _m hundr$s or ?\s&s ( horse-p[]1 motors or lamps might be op]at$ at consid]able di/ances f /ation>y s\rces4 ,b su* s*emes are m5tion$ m]ely z possibilities4 ,we %all h no ne$ to transmit p[] 9 ?is way4 ,we %all h no ne$ to transmit p[] at all4 ,ere _m g5]ations pass1 our ma*9]y w be driv5 by a p[] obta9able at any po9t ( ! univ]se4 ,?is idea is n novel4 ,m5 h be5 l$ to x long ago by in/9ct or reason4 ,x has be5 express$ 9 _m ways1 & 9 _m places1 9 ! hi/ory ( old & new4 ,we f9d x 9 ! delightful my? ( ,an!us1 :o d]ives p[] f ! e>?2 we f9d x among ! subtle speculations ( "o ( y\r spl5did ma!maticians1 & 9 _m h9ts & /atem5ts ( ?9k]s ( ! pres5t "t4 ,?r\gh\t space !re is en]gy4 ,is ?is en]gy /atic or k9etic8 ,if /atic our hopes are 9 va92 if k9etic--& ?is we "k x is1 = c]ta9--!n x is a m]e "q ( "t :5 m5 w succe$ 9 atta*+ _! ma*9]y to ! v :eelwork ( nature4 ,( all1 liv+ or dead1 ,crookes came ne>e/ to do+ x4 ,8 radiomet] w turn 9 ! light ( day & 9 ! d>kness ( ! night2 x w turn ev]y:]e :]e !re is heat1 & heat is ev]y:]e4 ,b1 un=tunately1 ?is beautiful little ma*9e1 :ile x goes d[n to po/]ity z ! mo/ int]e/+1 mu/ likewise be put on record z ! mo/ ineffici5t ma*9e ev] inv5t$6 ,! prec$+ exp]im5t is only "o ( _m equally int]e/+ exp]im5ts :i* may be p]=m$ by ! use ( only "o wire ) alt]nations ( high pot5tial & frequ5cy4 ,we may connect an insulat$ l9e to a s\rce ( su* curr5ts1 we may pass an inappreciable curr5t ov] ! l9e1 & on any po9t ( ! same we are able to obta9 a heavy curr5t1 capable ( fus+ a ?ick copp] wire4 ,or we may1 by ! help ( "s artifice1 decompose a solution 9 any electrolytic cell by connect+ only "o pole ( ! cell to ! l9e or s\rce ( en]gy4 ,or we may1 by atta*+ to ! l9e1 or only br++ into its vic9ity1 light up an inc&esc5t lamp1 an exhau/$ tube1 or a phosphoresc5t bulb4 ,h[ev] impracticable ?is plan ( work+ may appe> 9 _m cases1 x c]ta9ly seems practicable1 & ev5 recomm5dable1 9 ! production ( light4 ,a p]fect$ lamp w\ld require b little en]gy1 & if wires 7 us$ at all we ought to be able to supply t en]gy )\t a return wire4 ,x is n[ a fact t a body may be r5d]$ inc&esc5t or phosphoresc5t by br++ x ei!r 9 s+le contact or m]ely 9 ! vic9ity ( a s\rce ( electric impulses ( ! prop] "*1 & t 9 ?is mann] a quantity ( light suffici5t to af=d a practical illum9ant may be produc$4 ,x is1 !re=e1 to say ! lea/1 wor? :ile to attempt to det]m9e ! be/ conditions & to inv5t ! be/ appliances = atta9+ ?is object4 ,"s exp]i5ces h already be5 ga9$ 9 ?is direction1 & ,i w dwell on !m briefly1 9 ! hope t !y might prove useful4 ,! heat+ ( a conduct+ body inclos$ 9 a bulb1 & connect$ to a s\rce ( rapidly alt]nat+ electric impulses1 is dep5d5t on s _m ?+s ( a diff]5t nature1 t x w\ld be difficult to give a g5]ally applicable rule "u :i* ! maximum heat+ occurs4 ,z reg>ds ! size ( ! vessel1 ,i h lately f\nd t at ord9>y or only slightly diff]+ atmosph]ic pressures1 :5 air is a good insulator1 & h5ce practically ! same am\nt ( en]gy by a c]ta9 pot5tial & frequ5cy is giv5 (f f ! body1 :e!r ! bulb be small or l>ge1 ! body is br\ght to a high] temp]ature if enclos$ 9 a small bulb1 because ( ! bett] conf9em5t ( heat 9 ?is case4 ,at l[] pressures1 :5 air becomes m or less conduct+1 or if ! air be suffici5tly w>m$ to become conduct+1 ! body is r5d]$ m int5sely inc&esc5t 9 a l>ge bulb1 obvi\sly because1 "u o!rwise equal conditions ( te/1 m en]gy may be giv5 (f f ! body :5 ! bulb is l>ge4 ,at v high degrees ( exhau/ion1 :5 ! matt] 9 ! bulb becomes radiant1 a l>ge bulb has /ill an advantage1 b a comp>atively slight "o1 ov] ! small bulb4 ,f9ally1 at excessively high degrees ( exhau/ion1 :i* _c be rea*$ except by ! employm5t ( special means1 !re seems to be1 beyond a c]ta9 & r small size ( vessel1 no p]ceptible diff]5ce 9 ! heat+4 ,^! obs]vations 7 ! result ( a numb] ( exp]im5ts1 ( :i* "o1 %[+ ! effect ( ! size ( ! bulb at a high degree ( exhau/ion1 may be describ$ & %[n "h1 z x pres5ts a feature ( int]e/4 ,?ree sph]ical bulbs ( #b in*es1 #c in*es & #d in*es diamet] 7 tak51 & 9 ! c5tre ( ea* 0 m\nt$ an equal l5g? ( an ord9>y inc&esc5t lamp filam5t ( uni=m ?ickness4 ,9 ea* bulb ! piece ( filam5t 0 fa/5$ to ! lead+-9 wire ( plat9um1 conta9$ 9 a glass /em seal$ 9 ! bulb2 c>e be+ tak51 ( c\rse1 to make ev]y?+ z ne>ly alike z possible4 ,on ea* glass /em 9 ! inside ( ! bulb 0 slipp$ a highly poli%$ tube made ( alum9um %eet1 :i* fitt$ ! /em & 0 held on x by spr+ pressure4 ,! function ( ?is alum9um tube w be expla9$ subsequ5tly4 ,9 ea* bulb an equal l5g? ( filam5t protrud$ above ! metal tube4 ,x is suffici5t to say n[ t "u ^! conditions equal l5g?s ( filam5t ( ! same ?ickness--9 o!r words1 bodies ( equal bulk--7 br\ght to inc&esc5ce4 ,! ?ree bulbs 7 seal$ to a glass tube1 :i* 0 connect$ to a ,spr5gel pump4 ,:5 a high vacuum _h be5 rea*$1 ! glass tube c>ry+ ! bulbs 0 seal$ (f4 ,a curr5t 0 !n turn$ on successively on ea* bulb1 & x 0 f\nd t ! filam5ts came to ab\t ! same brightness1 &1 if any?+1 ! smalle/ bulb1 :i* 0 plac$ midway betwe5 ! two l>g] ones1 may h be5 slightly bright]4 ,?is result 0 expect$1 = :5 ei!r ( ! bulbs 0 connect$ to ! coil ! lum9osity spread ?r\gh ! o!r two1 h5ce ! ?ree bulbs con/itut$ really "o vessel4 ,:5 all ! ?ree bulbs 7 connect$ 9 multiple arc to ! coil1 9 ! l>ge/ ( !m ! filam5t gl[$ brighte/1 9 ! next small] x 0 a little less bright1 & 9 ! smalle/ x only came to r$ness4 ,! bulbs 7 !n seal$ (f & sep>ately tri$4 ,! brightness ( ! filam5ts 0 n[ su* z w\ld h be5 expect$ on ! supposition t ! en]gy giv5 (f 0 proportionate to ! surface ( ! bulb1 ?is surface 9 ea* case repres5t+ "o ( ! coat+s ( a cond5s]4 ,accord+ly1 !re 0 less diff]5ce betwe5 ! l>ge/ & ! middle siz$ ?an betwe5 ! latt] & ! smalle/ bulb4 ,an int]e/+ obs]vation 0 made 9 ?is exp]im5t4 ,! ?ree bulbs 7 susp5d$ f a /raight b>e wire connect$ to a t]m9al ( a coil1 ! l>ge/ bulb be+ plac$ at ! end ( ! wire1 at "s di/ance f x ! smalle/ bulb1 & at an equal di/ance f ! latt] ! middle-siz$ "o4 ,! c>bons gl[$ !n 9 bo? ! l>g] bulbs ab\t z expect$1 b ! smalle/ did n get its %>e by f>4 ,?is obs]vation l$ me to ex*ange ! position ( ! bulbs1 & ,i !n obs]v$ t :i*ev] ( ! bulbs 0 9 ! middle 0 by f> less bright ?an x 0 9 any o!r position4 ,?is my/ify+ result 01 ( c\rse1 f\nd to be due to ! electro/atic action betwe5 ! bulbs4 ,:5 !y 7 plac$ at a consid]able di/ance1 or :5 !y 7 atta*$ to ! corn]s ( an equilat]al triangle ( copp] wire1 !y gl[$ 9 ab\t ! ord] det]m9$ by _! surfaces4 ,z to ! %ape ( ! vessel1 x is also ( "s importance1 especially at high degrees ( exhau/ion4 ,( all ! possible con/ructions1 x seems t a sph]ical globe ) ! refractory body m\nt$ 9 its c5tre is ! be/ to employ4 ,by exp]i5ce x has be5 demon/rat$ t 9 su* a globe a refractory body ( a giv5 bulk is m easily br\ght to inc&esc5ce ?an :5 diff]5tly %ap$ bulbs are us$4 ,!re is also an advantage 9 giv+ to ! inc&esc5t body ! %ape ( a sph]e1 = self-evid5t reasons4 ,9 any case ! body %\ld be m\nt$ 9 ! c5tre1 :]e ! atoms reb\nd+ f ! glass collide4 ,?is object is be/ atta9$ 9 ! sph]ical bulb2 b x is also atta9$ 9 a cyl9drical vessel ) "o or two /raight filam5ts co9cid+ ) its axis1 & possibly also 9 p>abolical or sph]ical bulbs ) refractory body or bodies plac$ 9 ! focus or foci ( ! same2 ?\gh ! latt] is n probable1 z ! electrifi$ atoms %\ld 9 all cases reb\nd normally f ! surface !y /rike1 unless ! spe$ 7 excessive1 9 :i* case !y w\ld probably foll[ ! g5]al law ( reflection4 ,no matt] :at %ape ! vessel may h1 if ! exhau/ion be l[1 a filam5t m\nt$ 9 ! globe is br\ght to ! same degree ( inc&esc5ce 9 all p>ts2 b if ! exhau/ion be high & ! bulb be sph]ical or pe>-%ap$1 z usual1 focal po9ts =m & ! filam5t is heat$ to a high] degree at or ne> su* po9ts4 ,to illu/rate ! effect1 ,i h "h two small bulbs :i* are alike1 only "o is exhau/$ to a l[ & ! o!r to a v high degree4 ,:5 connect$ to ! coil1 ! filam5t 9 ! =m] gl[s uni=mly ?r\gh\t all its l5g?2 :]eas 9 ! latt]1 t portion ( ! filam5t :i* is 9 ! c5tre ( ! bulb gl[s f> m int5sely ?an ! re/4 ,a curi\s po9t is t ! ph5om5on occurs ev5 if two filam5ts are m\nt$ 9 a bulb1 ea* be+ connect$ to "o t]m9al ( ! coil1 &1 :at is /ill m curi\s1 if !y be v ne> toge!r1 provid$ ! vacuum be v high4 ,i not$ 9 exp]im5ts ) su* bulbs t ! filam5ts w\ld give way usually at a c]ta9 po9t1 & 9 ! fir/ trials ,i attribut$ x to a defect 9 ! c>bon4 ,b :5 ! ph5om5on occurr$ _m times 9 succession ,i recogniz$ its real cause4 ,9 ord] to br+ a refractory body inclos$ 9 a bulb to inc&esc5ce1 x is desirable1 on acc\nt ( economy1 t all ! en]gy suppli$ to ! bulb f ! s\rce %\ld rea* )\t loss ! body to be heat$2 f !re1 & f n[h]e else1 x %\ld be radiat$4 ,x is1 ( c\rse1 out ( ! "q to rea* ?is !oretical result1 b x is possible by a prop] con/ruction ( ! illum9at+ device to approximate x m or less4 ,= _m reasons1 ! refractory body is plac$ 9 ! c5tre ( ! bulb1 & x is usually support$ on a glass /em conta9+ ! lead+-9 wire4 ,z ! pot5tial ( ?is wire is alt]nat$1 ! r>efi$ gas surr\nd+ ! /em is act$ ^u inductively1 & ! glass /em is viol5tly bomb>d$ & heat$4 ,9 ?is mann] by f> ! great] portion ( ! en]gy suppli$ to ! bulb--especially :5 exce$+ly high frequ5cies are us$--may be lo/ = ! purpose contemplat$4 ,to obviate ?is loss1 or at lea/ to r$uce x to a m9imum1 ,i usually scre5 ! r>efi$ gas surr\nd+ ! /em f ! inductive action ( ! lead+-9 wire by provid+ ! /em ) a tube or coat+ ( conduct+ mat]ial4 ,x seems beyond d\bt t ! be/ among metals to employ = ?is purpose is alum9um1 on acc\nt ( its _m rem>kable prop]ties4 ,its only fault is t x is easily fusible1 &1 !re=e1 its di/ance f ! inc&esc+ body %\ld be prop]ly e/imat$4 ,usually1 a ?9 tube1 ( a diamet] some:at small] ?an t ( ! glass /em1 is made ( ! f9e/ alum9um %eet1 & slipp$ on ! /em4 ,! tube is conv5i5tly prep>$ by wrapp+ ar\nd a rod fa/5$ 9 a la! a piece ( alum9um %eet ( prop] size1 grasp+ ! %eet firmly ) clean *amois lea!r or blott+ pap]1 & sp9n+ ! rod v fa/4 ,! %eet is w\nd tightly ar\nd ! rod1 & a highly poli%$ tube ( "o or ?ree lay]s ( ! %eet is obta9$4 ,:5 slipp$ on ! /em1 ! pressure is g5]ally suffici5t to prev5t x f slipp+ (f1 b1 = safety1 ! l[] edge ( ! %eet may be turn$ inside4 ,! upp] inside corn] ( ! %eet--t is1 ! "o :i* is ne>e/ to ! refractory inc&esc5t body--%\ld be cut out diagonally1 z x (t5 happ5s t1 9 consequ5ce ( ! int5se heat1 ?is corn] turns t[>d ! inside & comes v ne> to1 or 9 contact )1 ! wire1 or filam5t1 support+ ! refractory body4 ,! great] "p ( ! en]gy suppli$ to ! bulb is !n us$ up 9 heat+ ! metal tube1 & ! bulb is r5d]$ useless = ! purpose4 ,! alum9um %eet %\ld project above ! glass /em m or less--"o in* or s--or else1 if ! glass be too close to ! inc&esc+ body1 x may be /rongly heat$ & become m or less conduct+1 :]eupon x may be ruptur$1 or may1 by its conductivity1 e/abli% a good electrical connection betwe5 ! metal tube & ! lead+-9 wire1 9 :i* case1 aga91 mo/ ( ! en]gy w be lo/ 9 heat+ ! =m]4 ,p]haps ! be/ way is to make ! top ( ! glass tube1 = ab\t an in*1 ( a mu* small] diamet]4 ,to /ill fur!r r$uce ! dang] aris+ f ! heat+ ( ! glass /em1 & also ) ! view ( prev5t+ an electrical connection betwe5 ! metal tube & ! electrode1 ,i pref]ably wrap ! /em ) sev]al lay]s ( ?9 mica1 :i* ext5ds at lea/ z f> z ! metal tube4 ,9 "s bulbs ,i h also us$ an outside insulat+ cov]4 ,! prec$+ rem>ks are only made to aid ! exp]im5t] 9 ! fir/ trials1 = ! difficulties :i* he enc\nt]s he may soon f9d means to ov]come 9 8 own way4 ,to illu/rate ! effect ( ! scre51 & ! advantage ( us+ x1 ,i h "h two bulbs ( ! same size1 ) _! /ems1 lead+-9 wires & inc&esc5t lamp filam5ts ti$ to ! latt]1 z ne>ly alike z possible4 ,! /em ( "o bulb is provid$ ) an alum9um tube1 ! /em ( ! o!r has none4 ,orig9ally ! two bulbs 7 jo9$ by a tube :i* 0 connect$ to a ,spr5gel pump4 ,:5 a high vacuum _h be5 rea*$1 fir/ ! connect+ tube1 & !n ! bulbs1 7 seal$ (f2 !y are !re=e ( ! same degree ( exhau/ion4 ,:5 !y are sep>ately connect$ to ! coil giv+ a c]ta9 pot5tial1 ! c>bon filam5t 9 ! bulb provid$ ) ! alum9um scre5 is r5d]$ highly inc&esc5t1 :ile ! filam5t 9 ! o!r bulb may1 ) ! same pot5tial1 n ev5 come to r$ness1 al?\gh 9 reality ! latt] bulb takes g5]ally m en]gy ?an ! =m]4 ,:5 !y are bo? connect$ toge!r to ! t]m9al1 ! diff]5ce is ev5 m app>5t1 %[+ ! importance ( ! scre5+4 ,! metal tube plac$ on ! /em conta9+ ! lead+-9 wire p]=ms really two di/9ct functions3 ,fir/1 x acts m or less z an electro/atic scre51 ?us economiz+ ! en]gy suppli$ to ! bulb2 &1 second1 to :atev] ext5t x may fail to act electro/atically1 x acts me*anically1 prev5t+ ! bomb>dm5t1 & consequ5tly int5se heat+ & possible det]ioration ( ! sl5d] support ( ! refractory inc&esc5t body1 or ( ! glass /em conta9+ ! lead+-9 wire4 ,i say sl5d] support1 = x is evid5t t 9 ord] to conf9e ! heat m completely to ! inc&esc+ body its support %\ld be v ?91 s z to c>ry away ! smalle/ possible am\nt ( heat by conduction4 ,( all ! supports us$ ,i h f\nd an ord9>y inc&esc5t lamp filam5t to be ! be/1 pr9cipally because among conductors x c )/& ! highe/ degree ( heat4 ,! effectiv5ess ( ! metal tube z an electro/atic scre5 dep5ds l>gely on ! degree ( exhau/ion4 ,at excessively high degrees ( exhau/ion--:i* are rea*$ by us+ great c>e & special means 9 connection ) ! ,spr5gel pump--:5 ! matt] 9 ! globe is 9 ! ultra-radiant /ate1 x acts mo/ p]fectly4 ,! %ad[ ( ! upp] edge ( ! tube is !n %>ply def9$ ^u ! bulb4 ,at a some:at l[] degree ( exhau/ion1 :i* is ab\t ! ord9>y non-/rik+ vacuum1 & g5]ally z long z ! matt] moves pr$om9antly 9 /raight l9es1 ! scre5 /ill does well4 ,9 elucidation ( ! prec$+ rem>k x is necess>y to /ate t :at is a non-/rik+ vacuum = a coil op]at$ z ord9>ily1 by impulses1 or curr5ts1 ( l[ frequ5cy1 is n s1 by f>1 :5 ! coil is op]at$ by curr5ts ( v high frequ5cy4 ,9 su* case ! dis*>ge may pass ) great fre$om ?r\gh ! r>efi$ gas ?r\gh :i* a l[ frequ5cy dis*>ge may n pass1 ev5 ?\gh ! pot5tial be mu* high]4 ,at ord9>y atmosph]ic pressures j ! rev]se rule holds good3 ! high] ! frequ5cy1 ! less ! sp>k dis*>ge is able to jump betwe5 ! t]m9als1 especially if !y are knobs or sph]es ( "s size4 ,f9ally1 at v l[ degrees ( exhau/ion1 :5 ! gas is well conduct+1 ! metal tube n only does n act z an electro/atic scre51 b ev5 is a drawback1 aid+ to a consid]able ext5t ! dissipation ( ! en]gy lat]ally f ! lead+-9 wire4 ,?is1 ( c\rse1 is to be expect$4 ,9 ?is case1 namely1 ! metal tube is 9 good electrical connection ) ! lead+-9 wire1 & mo/ ( ! bomb>dm5t is direct$ ^u ! tube4 ,z long z ! electrical connection is n good1 ! conduct+ tube is always ( "s advantage1 = al?\gh x may n greatly economize en]gy1 /ill x protects ! support ( ! refractory button1 & is ! means ( conc5trat+ m en]gy ^u ! same4 ,to :atev] ext5t ! alum9um tube p]=ms ! function ( a scre51 its usefulness is !re=e limit$ to v high degrees ( exhau/ion :5 x is insulat$ f ! electrode--t is1 :5 ! gas z a :ole is non-conduct+1 & ! molecules1 or atoms1 act z indep5d5t c>ri]s ( electric *>ges4 ,9 addition to act+ z a m or less effective scre51 9 ! true mean+ ( ! ^w1 ! conduct+ tube or coat+ may also act1 by reason ( its conductivity1 z a sort ( equaliz] or damp5] ( ! bomb>dm5t aga9/ ! /em4 ,to be explicit1 ,i assume ! action to be z foll[s3 ,suppose a rhy?mical bomb>dm5t to occur aga9/ ! conduct+ tube by reason ( its imp]fect action z a scre51 x c]ta9ly mu/ happ5 t "s molecules1 or atoms1 /rike ! tube soon] ?an o!rs4 ,^? :i* come fir/ 9 contact ) x give up _! sup]flu\s *>ge1 & ! tube is electrifi$1 ! electrification in/antly spread+ ov] its surface4 ,b ?is mu/ dim9i% ! en]gy lo/ 9 ! bomb>dm5t1 = two reasons3 fir/1 ! *>ge giv5 up by ! atoms spreads ov] a great area1 & h5ce ! electric d5sity at any po9t is small1 & ! atoms are repell$ ) less en]gy ?an !y w\ld be if !y /ruck aga9/ a good insulator2 secondly1 z ! tube is electrifi$ by ! atoms :i* fir/ come 9 contact ) x1 ! progress ( ! foll[+ atoms aga9/ ! tube is m or less *eck$ by ! repulsion :i* ! electrifi$ tube mu/ ex]t ^u ! simil>ly electrifi$ atoms4 ,?is repulsion may p]haps be suffici5t to prev5t a l>ge portion ( ! atoms f /rik+ ! tube1 b at any rate x mu/ dim9i% ! en]gy ( _! impact4 ,x is cle> t :5 ! exhau/ion is v l[1 & ! r>efi$ gas well conduct+1 nei!r ( ! above effects c occur1 &1 on ! o!r h&1 ! few] ! atoms1 ) ! great] fre$om !y move2 9 o!r words1 ! high] ! degree ( exhau/ion1 up to a limit1 ! m tell+ w be bo? ! effects4 ,illu/ration3 ,,fig4 #adg4 ,illu/ration3 ,,fig4 #adh4 ,:at ,i h j said may af=d an explanation ( ! ph5om5on obs]v$ by ,pr(4 ,crookes1 namely1 t a dis*>ge ?r\gh a bulb is e/abli%$ ) mu* great] facility :5 an insulator ?an :5 a conductor is pres5t 9 ! same4 ,9 my op9ion1 ! conductor acts z a damp5] ( ! motion ( ! atoms 9 ! two ways po9t$ out2 h5ce1 to cause a visible dis*>ge to pass ?r\gh ! bulb1 a mu* high] pot5tial is ne$$ if a conductor1 especially ( mu* surface1 be pres5t4 ,= ! sake ( elucidat+ ( "s ( ! rem>ks be=e made1 ,i mu/ n[ ref] to ,figs4 #adg1 #adh & #adi1 :i* illu/rate v>i\s arrangem5ts ) a type ( bulb mo/ g5]ally us$4 ,fig4 #adg is a section ?r\gh a sph]ical bulb ,l1 ) ! glass /em s1 conta9s ! lead+-9 wire w1 :i* has a lamp filam5t l fa/5$ to x1 s]v+ to support ! refractory button m 9 ! c5tre4 ,m is a %eet ( ?9 mica w\nd 9 sev]al lay]s ar\nd ! /em s1 & a is ! alum9um tube4 ,fig4 #adh illu/rates su* a bulb 9 a some:at m advanc$ /age ( p]fection4 ,a metallic tube ,s is fa/5$ by means ( "s cem5t to ! neck ( ! tube4 ,9 ! tube is screw$ a plug ,p1 ( insulat+ mat]ial1 9 ! c5tre ( :i* is fa/5$ a metallic t]m9al t1 = ! connection to ! lead+-9 wire w4 ,?is t]m9al mu/ be well insulat$ f ! metal tube ,s2 !re=e1 if ! cem5t us$ is conduct+--& mo/ g5]ally x is suffici5tly s--! space betwe5 ! plug ,p & ! neck ( ! bulb %\ld be fill$ ) "s good insulat+ mat]ial1 su* z mica p[d]4 ,fig4 #adi %[s a bulb made = exp]im5tal purposes4 ,9 ?is bulb ! alum9um tube is provid$ ) an ext]nal connection1 :i* s]ves to inve/igate ! effect ( ! tube "u v>i\s conditions4 ,x is ref]r$ to *iefly to sugge/ a l9e ( exp]im5t foll[$4 ,s9ce ! bomb>dm5t aga9/ ! /em conta9+ ! lead+-9 wire is due to ! inductive action ( ! latt] ^u ! r>efi$ gas1 x is ( advantage to r$uce ?is action z f> z practicable by employ+ a v ?9 wire1 surr\nd$ by a v ?ick insulation ( glass or o!r mat]ial1 & by mak+ ! wire pass+ ?r\gh ! r>efi$ gas z %ort z practicable4 ,to comb9e ^! features ,i employ a l>ge tube ,t 7,fig4 #aej71 :i* protrudes into ! bulb to "s di/ance1 & c>ries on ! top a v %ort glass /em s1 into :i* is seal$ ! lead+-9 wire w1 & ,i protect ! top ( ! glass /em aga9/ ! heat by a small alum9um tube a & a lay] ( mica und]nea? ! same1 z usual4 ,! wire w1 pass+ ?r\gh ! l>ge tube to ! outside ( ! bulb1 %\ld be well insulat$--) a glass tube1 = in/ance--& ! space betwe5 ought to be fill$ out ) "s excell5t insulator4 ,among _m insulat+ p[d]s ,i h f\nd t mica p[d] is ! be/ to employ4 ,if ?is precaution is n tak51 ! tube ,t1 protrud+ into ! bulb1 w surely be crack$ 9 consequ5ce ( ! heat+ by ! bru%es :i* are apt to =m 9 ! upp] "p ( ! tube1 ne> ! exhau/$ globe1 especially if ! vacuum be excell5t1 & !re=e ! pot5tial necess>y to op]ate ! lamp be v high4 ,illu/ration3 ,,fig4 #adi4 ,illu/ration3 ,,fig4 #aej4 ,fig4 #aea illu/rates a simil> arrangem5t1 ) a l>ge tube ,t protrud+ into ! "p ( ! bulb conta9+ ! refractory button m4 ,9 ?is case ! wire lead+ f ! outside into ! bulb is omitt$1 ! en]gy requir$ be+ suppli$ ?r\gh cond5s] coat+s ,c ,c4 ,! insulat+ pack+ ,p %\ld 9 ?is con/ruction be tightly fitt+ to ! glass1 & r wide1 or o!rwise ! dis*>ge might avoid pass+ ?r\gh ! wire w1 :i* connects ! inside cond5s] coat+ to ! inc&esc5t button m4 ,! molecul> bomb>dm5t aga9/ ! glass /em 9 ! bulb is a s\rce ( great tr\ble4 ,z an illu/ration ,i w cite a ph5om5on only too frequ5tly & unwill+ly obs]v$4 ,a bulb1 pref]ably a l>ge "o1 may be tak51 & a good conduct+ body1 su* z a piece ( c>bon1 may be m\nt$ 9 x ^u a plat9um wire seal$ 9 ! glass /em4 ,! bulb may be exhau/$ to a fairly high degree1 ne>ly to ! po9t :5 phosphoresc5ce beg9s to appe>4 ,:5 ! bulb is connect$ ) ! coil1 ! piece ( c>bon1 if small1 may become highly inc&esc5t at fir/1 b its brightness imm$iately dim9i%es1 & !n ! dis*>ge may break ?r\gh ! glass some:]e 9 ! middle ( ! /em1 9 ! =m ( bright sp>ks1 9 spite ( ! fact t ! plat9um wire is 9 good electrical connection ) ! r>efi$ gas ?r\gh ! piece ( c>bon or metal at ! top4 ,! fir/ sp>ks are s+ul>ly bright1 recall+ ^? drawn f a cle> surface ( m]cury4 ,b1 z !y heat ! glass rapidly1 !y1 ( c\rse1 lose _! brightness1 & cease :5 ! glass at ! ruptur$ place becomes inc&esc5t1 or g5]ally suffici5tly hot to conduct4 ,:5 obs]v$ = ! fir/ "t ! ph5om5on mu/ appe> v curi\s1 & %[s 9 a /rik+ mann] h[ radically diff]5t alt]nate curr5ts1 or impulses1 ( high frequ5cy behave1 z comp>$ ) /eady curr5ts1 or curr5ts ( l[ frequ5cy4 ,) su* curr5ts--namely1 ! latt]--! ph5om5on w\ld ( c\rse n occur4 ,:5 frequ5cies su* z are obta9$ by me*anical means are us$1 ,i ?9k t ! rupture ( ! glass is m or less ! consequ5ce ( ! bomb>dm5t1 :i* w>ms x up & impairs its insulat+ p[]2 b ) frequ5cies obta9able ) cond5s]s ,i h no d\bt t ! glass may give way )\t previ\s heat+4 ,al?\gh ?is appe>s mo/ s+ul> at fir/1 x is 9 reality :at we might expect to occur4 ,! en]gy suppli$ to ! wire lead+ into ! bulb is giv5 (f p>tly by direct action ?r\gh ! c>bon button1 & p>tly by inductive action ?r\gh ! glass surr\nd+ ! wire4 ,! case is ?us analog\s to t 9 :i* a cond5s] %unt$ by a conductor ( l[ resi/ance is connect$ to a s\rce ( alt]nat+ curr5t4 ,z long z ! frequ5cies are l[1 ! conductor gets ! mo/ & ! cond5s] is p]fectly safe2 b :5 ! frequ5cy becomes excessive1 ! role ( ! conductor may become q insignificant4 ,9 ! latt] case ! diff]5ce ( pot5tial at ! t]m9als ( ! cond5s] may become s great z to rupture ! dielectric1 not)/&+ ! fact t ! t]m9als are jo9$ by a conductor ( l[ resi/ance4 ,x is1 ( c\rse1 n necess>y1 :5 x is desir$ to produce ! inc&esc5ce ( a body inclos$ 9 a bulb by means ( ^! curr5ts1 t ! body %\ld be a conductor1 = ev5 a p]fect non-conductor may be q z readily heat$4 ,= ?is purpose x is suffici5t to surr\nd a conduct+ electrode ) a non-conduct+ mat]ial1 z1 = in/ance1 9 ! bulb describ$ be=e 9 ,fig4 #aej1 9 :i* a ?9 inc&esc5t lamp filam5t is coat$ ) a non-conductor1 & supports a button ( ! same mat]ial on ! top4 ,at ! />t ! bomb>dm5t goes on by inductive action ?r\gh ! non-conductor1 until ! same is suffici5tly heat$ to become conduct+1 :5 ! bomb>dm5t cont9ues 9 ! ord9>y way4 ,illu/ration3 ,,fig4 #aea4 ,illu/ration3 ,,fig4 #aeb4 ,a diff]5t arrangem5t us$ 9 "s ( ! bulbs con/ruct$ is illu/rat$ 9 ,fig4 #aeb4 ,9 ?is in/ance a non-conductor m is m\nt$ 9 a piece ( common arc light c>bon s z to project "s small di/ance above ! latt]4 ,! c>bon piece is connect$ to ! lead+-9 wire pass+ ?r\gh a glass /em1 :i* is wrapp$ ) sev]al lay]s ( mica4 ,an alum9um tube a is employ$ z usual = scre5+4 ,x is s arrang$ t x rea*es v ne>ly z high z ! c>bon & only ! non-conductor m projects a little above x4 ,! bomb>dm5t goes at fir/ aga9/ ! upp] surface ( c>bon1 ! l[] p>ts be+ protect$ by ! alum9um tube4 ,z soon1 h[ev]1 z ! non-conductor m is heat$ x is r5d]$ good conduct+1 & !n x becomes ! c5tre ( ! bomb>dm5t1 be+ mo/ expos$ to ! same4 ,i h also con/ruct$ dur+ ^! exp]im5ts _m su* s+le-wire bulbs ) or )\t int]nal electrode1 9 :i* ! radiant matt] 0 project$ aga9/1 or focus$ ^u1 ! body to be r5d]$ inc&esc5t4 ,fig4 #aec 7page #bfc7 illu/rates "o ( ! bulbs us$4 ,x consi/s ( a sph]ical globe ,l1 provid$ ) a long neck n1 on top1 = increas+ ! action 9 "s cases by ! application ( an ext]nal conduct+ coat+4 ,! globe ,l is bl[n out on ! bottom into a v small bulb b1 :i* s]ves to hold x firmly 9 a socket ,s ( insulat+ mat]ial into :i* x is cem5t$4 ,a f9e lamp filam5t f1 support$ on a wire w1 passes ?r\gh ! c5tre ( ! globe ,l4 ,! filam5t is r5d]$ inc&esc5t 9 ! middle portion1 :]e ! bomb>dm5t proce$+ f ! l[] inside surface ( ! globe is mo/ int5se4 ,! l[] portion ( ! globe1 z f> z ! socket ,s rea*es1 is r5d]$ conduct+1 ei!r by a t9foil coat+ or o!rwise1 & ! ext]nal electrode is connect$ to a t]m9al ( ! coil4 ,! arrangem5t diagrammatically indicat$ 9 ,fig4 #aec 0 f\nd to be an inf]ior "o :5 x 0 desir$ to r5d] inc&esc5t a filam5t or button support$ 9 ! c5tre ( ! globe1 b x 0 conv5i5t :5 ! object 0 to excite phosphoresc5ce4 ,9 _m exp]im5ts 9 :i* bodies ( diff]5t k9d 7 m\nt$ 9 ! bulb z1 = in/ance1 indicat$ 9 ,fig4 #aeb1 "s obs]vations ( int]e/ 7 made4 ,x 0 f\nd1 among o!r ?+s1 t 9 su* cases1 no matt] :]e ! bomb>dm5t began1 j z soon z a high temp]ature 0 rea*$ !re 0 g5]ally "o ( ! bodies :i* seem$ to take mo/ ( ! bomb>dm5t ^u itself1 ! o!r1 or o!rs1 be+ !reby reliev$4 ,! quality appe>$ to dep5d pr9cipally on ! po9t ( fusion1 & on ! facility ) :i* ! body 0 evaporat$1 or1 g5]ally speak+1 dis9tegrat$--mean+ by ! latt] t]m n only ! ?r[+ (f ( atoms1 b likewise ( l>ge lumps4 ,! obs]vation made 0 9 accordance ) g5]ally accept$ notions4 ,9 a highly exhau/$ bulb1 electricity is c>ri$ (f f ! electrode by indep5d5t c>ri]s1 :i* are p>tly ! atoms1 or molecules1 ( ! residual atmosph]e1 & p>tly ! atoms1 molecules1 or lumps ?r[n (f f ! electrode4 ,if ! electrode is compos$ ( bodies ( diff]5t "*1 & if "o ( ^! is m easily dis9tegrat$ ?an ! o!r1 mo/ ( ! electricity suppli$ is c>ri$ (f f t body1 :i* is !n br\ght to a high] temp]ature ?an ! o!rs1 & ?is ! m1 z ^u an increase ( ! temp]ature ! body is /ill m easily dis9tegrat$4 ,x seems to me q probable t a simil> process takes place 9 ! bulb ev5 ) a homog5e\s electrode1 & ,i ?9k x to be ! pr9cipal cause ( ! dis9tegration4 ,!re is b\nd to be "s irregul>ity1 ev5 if ! surface is highly poli%$1 :i*1 ( c\rse1 is impossible ) mo/ ( ! refractory bodies employ$ z electrodes4 ,assume t a po9t ( ! electrode gets hott]2 in/antly mo/ ( ! dis*>ge passes ?r\gh t po9t1 & a m9ute pat* x probably fus$ & evaporat$4 ,x is n[ possible t 9 consequ5ce ( ! viol5t dis9tegration ! spot attack$ s9ks 9 temp]ature1 or t a c\nt] =ce is creat$1 z 9 an arc2 at any rate1 ! local te>+ (f meets ) ! limitations incid5t to ! exp]im5t1 :]eupon ! same process occurs on ano!r place4 ,to ! eye ! electrode appe>s uni=mly brilliant1 b !re are ^u x po9ts con/antly %ift+ & w&]+ ar\nd1 ( a temp]ature f> above ! mean1 & ?is mat]ially ha/5s ! process ( det]ioration4 ,t "s su* ?+ occurs1 at lea/ :5 ! electrode is at a l[] temp]ature1 suffici5t exp]im5tal evid5ce c be obta9$ 9 ! foll[+ mann]3 ,exhau/ a bulb to a v high degree1 s t ) a fairly high pot5tial ! dis*>ge _c pass--t is1 n a lum9\s "o1 = a weak invisible dis*>ge occurs always1 9 all probability4 ,n[ raise sl[ly & c>efully ! pot5tial1 leav+ ! prim>y curr5t on no m ?an = an in/ant4 ,at a c]ta9 po9t1 two1 ?ree1 or half a doz5 phosphoresc5t spots w appe> on ! globe4 ,^! places ( ! glass are evid5tly m viol5tly bomb>d$ ?an o!rs1 ?is be+ due to ! unev5ly di/ribut$ electric d5sity1 necessitat$1 ( c\rse1 by %>p projections1 or1 g5]ally speak+1 irregul>ities ( ! electrode4 ,b ! lum9\s pat*es are con/antly *ang+ 9 position1 :i* is especially well obs]vable if "o manages to produce v few1 & ?is indicates t ! configuration ( ! electrode is rapidly *ang+4 ,f exp]i5ces ( ?is k9d ,i am l$ to inf] t1 9 ord] to be mo/ durable1 ! refractory button 9 ! bulb %\ld be 9 ! =m ( a sph]e ) a highly poli%$ surface4 ,su* a small sph]e c\ld be manufactur$ f a diamond or "s o!r cry/al1 b a bett] way w\ld be to fuse1 by ! employm5t ( extreme degrees ( temp]ature1 "s oxide--z1 = in/ance1 zirconia--into a small drop1 & !n keep x 9 ! bulb at a temp]ature some:at bel[ its po9t ( fusion4 ,int]e/+ & useful results c1 no d\bt1 be rea*$ 9 ! direction ( extreme degrees ( heat4 ,h[ c su* high temp]atures be arriv$ at8 ,h[ are ! highe/ degrees ( heat rea*$ 9 nature8 ,by ! impact ( />s1 by high spe$s & collisions4 ,9 a collision any rate ( heat g5]ation may be atta9$4 ,9 a *emical process we are limit$4 ,:5 oxyg5 & hydrog5 comb9e1 !y fall1 metaphorically speak+1 f a def9ite height4 ,we _c g v f> ) a bla/1 nor by conf9+ heat 9 a furnace1 b 9 an exhau/$ bulb we c conc5trate any am\nt ( en]gy ^u a m9ute button4 ,leav+ practicability out ( consid]ation1 ?is1 !n1 w\ld be ! means :i*1 9 my op9ion1 w\ld enable u to rea* ! highe/ temp]ature4 ,b a great difficulty :5 proce$+ 9 ?is way is enc\nt]$1 namely1 9 mo/ cases ! body is c>ri$ (f be=e x c fuse & =m a drop4 ,?is difficulty exi/s pr9cipally ) an oxide1 su* z zirconia1 because x _c be compress$ 9 s h>d a cake t x w\ld n be c>ri$ (f quickly4 ,i h endeavor$ repeat$ly to fuse zirconia1 plac+ x 9 a cup ( arc light c>bon1 z indicat$ 9 ,fig4 #aeb4 ,x gl[$ ) a mo/ int5se light1 & ! /ream ( ! p>ticles project$ out ( ! c>bon cup 0 ( a vivid :ite2 b :e!r x 0 compress$ 9 a cake or made into a pa/e ) c>bon1 x 0 c>ri$ (f be=e x c\ld be fus$4 ,! c>bon cup1 conta9+ zirconia1 _h to be m\nt$ v l[ 9 ! neck ( a l>ge bulb1 z ! heat+ ( ! glass by ! project$ p>ticles ( ! oxide 0 s rapid t 9 ! fir/ trial ! bulb 0 crack$ almo/ 9 an in/ant1 :5 ! curr5t 0 turn$ on4 ,! heat+ ( ! glass by ! project$ p>ticles 0 f\nd to be always great] :5 ! c>bon cup conta9$ a body :i* 0 rapidly c>ri$ (f--,i presume1 because 9 su* cases1 ) ! same pot5tial1 high] spe$s 7 rea*$1 & also because1 p] unit ( "t1 m matt] 0 project$--t is1 m p>ticles w\ld /rike ! glass4 ,! be=e-m5tion$ difficulty did n exi/1 h[ev]1 :5 ! body m\nt$ 9 ! c>bon cup (f]$ great resi/ance to det]ioration4 ,= in/ance1 :5 an oxide 0 fir/ fus$ 9 an oxyg5 bla/1 & !n m\nt$ 9 ! bulb1 x melt$ v readily into a drop4 ,g5]ally1 dur+ ! process ( fusion1 magnific5t light effects 7 not$1 ( :i* x w\ld be difficult to give an adequate idea4 ,fig4 #aeb is int5d$ to illu/rate ! effect obs]v$ ) a ruby drop4 ,at fir/ "o may see a n>r[ funnel ( :ite light project$ aga9/ ! top ( ! globe1 :]e x produces an irregul>ly outl9$ phosphoresc5t pat*4 ,:5 ! po9t ( ! ruby fuses1 ! phosphoresc5ce becomes v p[]ful2 b z ! atoms are project$ ) mu* great] spe$ f ! surface ( ! drop1 soon ! glass gets hot & tir$1 & n[ only ! out] edge ( ! pat* gl[s4 ,9 ?is mann] an int5sely phosphoresc5t1 %>ply def9$ l9e1 l1 correspond+ to ! outl9e ( ! drop1 is produc$1 :i* spreads sl[ly ov] ! globe z ! drop gets l>g]4 ,:5 ! mass beg9s to boil1 small bubbles & cavities are =m$1 :i* cause d>k color$ spots to sweep across ! globe4 ,! bulb may be turn$ d[nw>d )\t fe> ( ! drop fall+ (f1 z ! mass possesses consid]able viscosity4 ,i may m5tion "h ano!r feature ( "s int]e/1 :i* ,i believe to h not$ 9 ! c\rse ( ^! exp]im5ts1 ?\gh ! obs]vations d n am\nt to a c]titude4 ,x appe>$ t "u ! molecul> impact caus$ by ! rapidly alt]nat+ pot5tial1 ! body 0 fus$ & ma9ta9$ 9 t /ate at a l[] temp]ature 9 a highly exhau/$ bulb ?an 0 ! case at normal pressure & application ( heat 9 ! ord9>y way--t is1 at lea/1 judg+ f ! quantity ( ! light emitt$4 ,"o ( ! exp]im5ts p]=m$ may be m5tion$ "h by way ( illu/ration4 ,a small piece ( pumice /one 0 /uck on a plat9um wire1 & fir/ melt$ to x 9 a gas burn]4 ,! wire 0 next plac$ betwe5 two pieces ( *>coal1 & a burn] appli$1 s z to produce an int5se heat1 suffici5t to melt d[n ! pumice /one into a small glass-l button4 ,! plat9um wire _h to be tak5 ( suffici5t ?ickness1 to prev5t its melt+ 9 ! fire4 ,:ile 9 ! *>coal fire1 or :5 held 9 a burn] to get a bett] idea ( ! degree ( heat1 ! button gl[$ ) great brilliancy4 ,! wire ) ! button 0 !n m\nt$ 9 a bulb1 & ^u exhau/+ ! same to a high degree1 ! curr5t 0 turn$ on sl[ly1 s z to prev5t ! crack+ ( ! button4 ,! button 0 heat$ to ! po9t ( fusion1 & :5 x melt$1 x did n1 app>5tly1 gl[ ) ! same brilliancy z be=e1 & ?is w\ld indicate a l[] temp]ature4 ,leav+ out ( consid]ation ! obs]v]'s possible1 & ev5 probable1 error1 ! "q is1 c a body "u ^! conditions be br\ght f a solid to a liquid /ate ) ! evolution ( less light8 ,:5 ! pot5tial ( a body is rapidly alt]nat$1 x is c]ta9 t ! /ructure is j>r$4 ,:5 ! pot5tial is v high1 al?\gh ! vibrations may be few--say #bj1jjj p] second--! effect ^u ! /ructure may be consid]able4 ,suppose1 = example1 t a ruby is melt$ into a drop by a /eady application ( en]gy4 ,:5 x =ms a drop1 x w emit visible & invisible waves1 :i* w be 9 a def9ite ratio1 & to ! eye ! drop w appe> to be ( a c]ta9 brilliancy4 ,next1 suppose we dim9i% to any degree we *oose ! en]gy /eadily suppli$1 &1 in/ead1 supply en]gy :i* rises & falls accord+ to a c]ta9 law4 ,n[1 :5 ! drop is =m$1 !re w be emitt$ f x ?ree diff]5t k9ds ( vibrations--! ord9>y visible1 & two k9ds ( invisible waves3 t is1 ! ord9>y d>k waves ( all l5g?s1 &1 9 addition1 waves ( a well def9$ "*4 ,! latt] w\ld n exi/ by a /eady supply ( ! en]gy2 /ill !y help to j> & loos5 ! /ructure4 ,if ?is really be ! case1 !n ! ruby drop w emit relatively less visible & m invisible waves ?an be=e4 ,?us x w\ld seem t :5 a plat9um wire1 = in/ance1 is fus$ by curr5ts alt]nat+ ) extreme rapidity1 x emits at ! po9t ( fusion less light & m visible radiation ?an x does :5 melt$ by a /eady curr5t1 ?\gh ! total en]gy us$ up 9 ! process ( fusion is ! same 9 bo? cases4 ,or1 to cite ano!r example1 a lamp filam5t is n capable ( )/&+ z long ) curr5ts ( extreme frequ5cy z x does ) /eady curr5ts1 assum+ t x be work$ at ! same lum9\s int5sity4 ,?is means t = rapidly alt]nat+ curr5ts ! filam5t %\ld be %ort] & ?ick]4 ,! high] ! frequ5cy--t is1 ! great] ! dep>ture f ! /eady fl[--! worse x w\ld be = ! filam5t4 ,b if ! tru? ( ?is rem>k 7 demon/rat$1 x w\ld be errone\s to conclude t su* a refractory button z us$ 9 ^! bulbs w\ld be det]iorat$ quick] by curr5ts ( extremely high frequ5cy ?an by /eady or l[ frequ5cy curr5ts4 ,f exp]i5ce ,i may say t j ! opposite holds good3 ! button )/&s ! bomb>dm5t bett] ) curr5ts ( v high frequ5cy4 ,b ?is is due to ! fact t a high frequ5cy dis*>ge passes ?r\gh a r>efi$ gas ) mu* great] fre$om ?an a /eady or l[ frequ5cy dis*>ge1 & ?is w mean t ) ! =m] we c "w ) a l[] pot5tial or ) a less viol5t impact4 ,z long1 !n1 z ! gas is ( no consequ5ce1 a /eady or l[ frequ5cy curr5t is bett]2 b z soon z ! action ( ! gas is desir$ & important1 high frequ5cies are pref]able4 ,9 ! c\rse ( ^! exp]im5ts a great _m trials 7 made ) all k9ds ( c>bon buttons4 ,electrodes made ( ord9>y c>bon buttons 7 decid$ly m durable :5 ! buttons 7 obta9$ by ! application ( enorm\s pressure4 ,electrodes prep>$ by deposit+ c>bon 9 well kn[n ways did n %[ up well2 !y black5$ ! globe v quickly4 ,f _m exp]i5ces ,i conclude t lamp filam5ts obta9$ 9 ?is mann] c be advantage\sly us$ only ) l[ pot5tials & l[ frequ5cy curr5ts4 ,"s k9ds ( c>bon )/& s well t1 9 ord] to br+ !m to ! po9t ( fusion1 x is necess>y to employ v small buttons4 ,9 ?is case ! obs]vation is r5d]$ v difficult on acc\nt ( ! int5se heat produc$4 ,nev]!less !re c be no d\bt t all k9ds ( c>bon are fus$ "u ! molecul> bomb>dm5t1 b ! liquid /ate mu/ be "o ( great in/ability4 ,( all ! bodies tri$ !re 7 two :i* )/ood be/--diamond & c>borundum4 ,^! two %[$ up ab\t equally1 b ! latt] 0 pref]able = _m reasons4 ,z x is m ?an likely t ?is body is n yet g5]ally kn[n1 ,i w v5ture to call y\r att5tion to x4 ,x has be5 rec5tly produc$ by ,mr4 ,e4 ,g4 ,a*eson1 ( ,monongahela ,city1 ,pa41 ,u4 ,s4 ,a4 ,x is int5d$ to replace ord9>y diamond p[d] = poli%+ preci\s /ones1 etc41 & ,i h be5 in=m$ t x accompli%es ?is object q successfully4 ,i d n "k :y ! "n c>borundum has be5 giv5 to x1 unless !re is some?+ 9 ! process ( its manufacture :i* ju/ifies ?is selection4 ,?r\gh ! k9dness ( ! inv5tor1 ,i obta9$ a %ort :ile ago "s samples :i* ,i desir$ to te/ 9 reg>d to _! qualities ( phosphoresc5ce & capability ( )/&+ high degrees ( heat4 ,c>borundum c be obta9$ 9 two =ms--9 ! =m ( cry/als & ( p[d]4 ,! =m] appe> to ! nak$ eye d>k color$1 b are v brilliant2 ! latt] is ( ne>ly ! same color z ord9>y diamond p[d]1 b v mu* f9]4 ,:5 view$ "u a microscope ! samples ( cry/als giv5 to me did n appe> to h any def9ite =m1 b r resembl$ pieces ( brok5 up egg coal ( f9e quality4 ,! majority 7 opaque1 b !re 7 "s :i* 7 transp>5t & color$4 ,! cry/als are a k9d ( c>bon conta9+ "s impurities2 !y are extremely h>d1 & )/& = a long "t ev5 an oxyg5 bla/4 ,:5 ! bla/ is direct$ aga9/ !m !y at fir/ =m a cake ( "s compactness1 probably 9 consequ5ce ( ! fusion ( impurities !y conta94 ,! mass )/&s = a v long "t ! bla/ )\t fur!r fusion2 b a sl[ c>ry+ (f1 or burn+1 occurs1 &1 f9ally1 a small quantity ( a glass-l residue is left1 :i*1 ,i suppose1 is melt$ alum9a4 ,:5 compress$ /rongly !y conduct v well1 b n z well z ord9>y c>bon4 ,! p[d]1 :i* is obta9$ f ! cry/als 9 "s way1 is practically non-conduct+4 ,x af=ds a magnific5t poli%+ mat]ial = /ones4 ,! "t has be5 too %ort to make a satisfactory /udy ( ! prop]ties ( ?is product1 b en\gh exp]i5ce has be5 ga9$ 9 a few weeks ,i h exp]im5t$ ^u x to say t x does possess "s rem>kable prop]ties 9 _m respects4 ,x )/&s excessively high degrees ( heat1 x is little det]iorat$ by molecul> bomb>dm5t1 & x does n black5 ! globe z ord9>y c>bon does4 ,! only difficulty :i* ,i h exp]i5c$ 9 its use 9 connection ) ^! exp]im5ts 0 to f9d "s b9d+ mat]ial :i* w\ld resi/ ! heat & ! effect ( ! bomb>dm5t z successfully z c>borundum itself does4 ,i h "h a numb] ( bulbs :i* ,i h provid$ ) buttons ( c>borundum4 ,to make su* a button ( c>borundum cry/als ,i proce$ 9 ! foll[+ mann]3 ,i take an ord9>y lamp filam5t & dip its po9t 9 t>1 or "s o!r ?ick sub/ance or pa9t :i* may be readily c>boniz$4 ,i next pass ! po9t ( ! filam5t ?r\gh ! cry/als1 & !n hold x v]tically ov] a hot plate4 ,! t> s(t5s & =ms a drop on ! po9t ( ! filam5t1 ! cry/als adh]+ to ! surface ( ! drop4 ,by regulat+ ! di/ance f ! plate ! t> is sl[ly dri$ out & ! button becomes solid4 ,i !n once m dip ! button 9 t> & hold x aga9 ov] a plate until ! t> is evaporat$1 leav+ only a h>d mass :i* firmly b9ds ! cry/als4 ,:5 a l>g] button is requir$ ,i repeat ! process sev]al times1 & ,i g5]ally also cov] ! filam5t a c]ta9 di/ance bel[ ! button ) cry/als4 ,! button be+ m\nt$ 9 a bulb1 :5 a good vacuum has be5 rea*$1 fir/ a weak & !n a /rong dis*>ge is pass$ ?r\gh ! bulb to c>bonize ! t> & expel all gases1 & lat] x is br\ght to a v int5se inc&esc5ce4 ,:5 ! p[d] is us$ ,i h f\nd x be/ to proce$ z foll[s3 ,i make a ?ick pa9t ( c>borundum & t>1 & pass a lamp filam5t ?r\gh ! pa9t4 ,tak+ !n mo/ ( ! pa9t (f by rubb+ ! filam5t aga9/ a piece ( *amois lea!r1 ,i hold x ov] a hot plate until ! t> evaporates & ! coat+ becomes firm4 ,i repeat ?is process z _m times z x is necess>y to obta9 a c]ta9 ?ickness ( coat+4 ,on ! po9t ( ! coat$ filam5t ,i =m a button 9 ! same mann]4 ,!re is no d\bt t su* a button--prop]ly prep>$ "u great pressure--( c>borundum1 especially ( p[d] ( ! be/ quality1 w )/& ! effect ( ! bomb>dm5t fully z well z any?+ we "k4 ,! difficulty is t ! b9d+ mat]ial gives way1 & ! c>borundum is sl[ly ?r[n (f aft] "s "t4 ,z x does n seem to black5 ! globe 9 ! lea/1 x might be f\nd useful = coat+ ! filam5ts ( ord9>y inc&esc5t lamps1 & ,i ?9k t x is ev5 possible to produce ?9 ?reads or /icks ( c>borundum :i* w replace ! ord9>y filam5ts 9 an inc&esc5t lamp4 ,a c>borundum coat+ seems to be m durable ?an o!r coat+s1 n only because ! c>borundum c )/& high degrees ( heat1 b also because x seems to unite ) ! c>bon bett] ?an any o!r mat]ial ,i h tri$4 ,a coat+ ( zirconia or any o!r oxide1 = in/ance1 is f> m quickly de/roy$4 ,i prep>$ buttons ( diamond du/ 9 ! same mann] z ( c>borundum1 & ^! came 9 durability ne>e/ to ^? prep>$ ( c>borundum1 b ! b9d+ pa/e gave way mu* m quickly 9 ! diamond buttons2 ?is1 h[ev]1 ,i attribut$ to ! size & irregul>ity ( ! gra9s ( ! diamond4 ,x 0 ( int]e/ to f9d :e!r c>borundum possesses ! quality ( phosphoresc5ce4 ,"o is1 ( c\rse1 prep>$ to enc\nt] two difficulties3 fir/1 z reg>ds ! r\gh product1 ! cry/als1 !y are good conduct+1 & x is a fact t conductors d n phosphoresce2 second1 ! p[d]1 be+ exce$+ly f9e1 w\ld n be apt to exhibit v prom95tly ?is quality1 s9ce we "k t :5 cry/als1 ev5 su* z diamond or ruby1 are f9ely p[d]$1 !y lose ! prop]ty ( phosphoresc5ce to a consid]able degree4 ,! "q pres5ts itself "h1 c a conductor phosphoresce8 ,:at is !re 9 su* a body z a metal1 = in/ance1 t w\ld deprive x ( ! quality ( phosphores5ce1 unless x is t prop]ty :i* *>act]izes x z a conductor8 ,= x is a fact t mo/ ( ! phosphoresc5t bodies lose t quality :5 !y are suffici5tly heat$ to become m or less conduct+4 ,!n1 if a metal be 9 a l>ge measure1 or p]haps entirely1 depriv$ ( t prop]ty1 x %\ld be capable ( phosphores5ce4 ,!re=e x is q possible t at "s extremely high frequ5cy1 :5 behav+ practically z a non-conductor1 a metal or any o!r conductor might exhibit ! quality ( phosphores5ce1 ev5 ?\gh x be entirely incapable ( phosphoresc+ "u ! impact ( a l[-frequ5cy dis*>ge4 ,!re is1 h[ev]1 ano!r possible way h[ a conductor might at lea/ appe> to phosphoresce4 ,consid]able d\bt /ill exi/s z to :at really is phosphoresc5ce1 & z to :e!r ! v>i\s ph5om5a compris$ "u ?is head are due to ! same causes4 ,suppose t 9 an exhau/$ bulb1 "u ! molecul> impact1 ! surface ( a piece ( metal or o!r conductor is r5d]$ /rongly lum9\s1 b at ! same "t x is f\nd t x rema9s comp>atively cool1 w\ld n ?is lum9osity be call$ phosphoresc5ce8 ,n[ su* a result1 !oretically at lea/1 is possible1 = x is a m]e "q ( pot5tial or spe$4 ,assume ! pot5tial ( ! electrode1 & consequ5tly ! spe$ ( ! project$ atoms1 to be suffici5tly high1 ! surface ( ! metal piece1 aga9/ :i* ! atoms are project$1 w\ld be r5d]$ highly inc&esc5t1 s9ce ! process ( heat g5]ation w\ld be incomp>ably fa/] ?an t ( radiat+ or conduct+ away f ! surface ( ! collision4 ,9 ! eye ( ! obs]v] a s+le impact ( ! atoms w\ld cause an in/antane\s fla%1 b if ! impacts 7 repeat$ ) suffici5t rapidity1 !y w\ld produce a cont9u\s impression ^u 8 ret9a4 ,to him !n ! surface ( ! metal w\ld appe> cont9u\sly inc&esc5t & ( con/ant lum9\s int5sity1 :ile 9 reality ! light w\ld be ei!r int]mitt5t1 or at lea/ *ang+ p]iodically 9 int5sity4 ,! metal piece w\ld rise 9 temp]ature until equilibrium 0 atta9$--t is1 until ! en]gy cont9u\sly radiat$ w\ld equal t int]mitt5tly suppli$4 ,b ! suppli$ en]gy might "u su* conditions n be suffici5t to br+ ! body to any m ?an a v mod]ate mean temp]ature1 especially if ! frequ5cy ( ! atomic impacts be v l[--j en\gh t ! fluctuation ( ! int5sity ( ! light emitt$ c\ld n be detect$ by ! eye4 ,! body w\ld n[1 ow+ to ! mann] 9 :i* ! en]gy is suppli$1 emit a /rong light1 & yet be at a comp>atively v l[ mean temp]ature4 ,h[ %\ld ! obs]v] "n ! lum9osity ?us produc$8 ,ev5 if ! analysis ( ! light w\ld tea* him some?+ def9ite1 /ill he w\ld probably rank x "u ! ph5om5a ( phosphoresc5ce4 ,x is conceivable t 9 su* a way bo? conduct+ & non-conduct+ bodies may be ma9ta9$ at a c]ta9 lum9\s int5sity1 b ! en]gy requir$ w\ld v greatly v>y ) ! nature & prop]ties ( ! bodies4 ,^! & "s =ego+ rem>ks ( a speculative nature 7 made m]ely to br+ out curi\s features ( alt]nate curr5ts or electric impulses4 ,by _! help we may cause a body to emit m light1 :ile at a c]ta9 mean temp]ature1 ?an x w\ld emit if br\ght to t temp]ature by a /eady supply2 &1 aga91 we may br+ a body to ! po9t ( fusion1 & cause x to emit less light ?an :5 fus$ by ! application ( en]gy 9 ord9>y ways4 ,x all dep5ds on h[ we supply ! en]gy1 & :at k9d ( vibrations we set up2 9 "o case ! vibrations are m1 9 ! o!r less1 adapt$ to affect our s5se ( vision4 ,"s effects1 :i* ,i _h n obs]v$ be=e1 obta9$ ) c>borundum 9 ! fir/ trials1 ,i attribut$ to phosphoresc5ce1 b 9 subsequ5t exp]im5ts x appe>$ t x 0 devoid ( t quality4 ,! cry/als possess a notewor?y feature4 ,9 a bulb provid$ ) a s+le electrode 9 ! %ape ( a small circul> metal disc1 = in/ance1 at a c]ta9 degree ( exhau/ion ! electrode is cov]$ ) a milky film1 :i* is sep>at$ by a d>k space f ! gl[ fill+ ! bulb4 ,:5 ! metal disc is cov]$ ) c>borundum cry/als1 ! film is f> m int5se1 & sn[-:ite4 ,?is ,i f\nd lat] to be m]ely an effect ( ! bright surface ( ! cry/als1 = :5 an alum9um electrode 0 highly poli%$1 x exhibit$ m or less ! same ph5om5on4 ,i made a numb] ( exp]im5ts ) ! samples ( cry/als obta9$1 pr9cipally because x w\ld h be5 ( special int]e/ to f9d t !y are capable ( phosphoresc5ce1 on acc\nt ( _! be+ conduct+4 ,i c\ld n produce phosphoresc5ce di/9ctly1 b ,i mu/ rem>k t a decisive op9ion _c be =m$ until o!r exp]im5t]s h gone ov] ! same gr\nd4 ,! p[d] behav$ 9 "s exp]im5ts z ?\gh x conta9$ alum9a1 b x did n exhibit ) suffici5t di/9ctness ! r$ ( ! latt]4 ,its dead color bright5s consid]ably "u ! molecul> impact1 b ,i am n[ conv9c$ x does n phosphoresce4 ,/ill1 ! te/s ) ! p[d] are n conclusive1 because p[d]$ c>borundum probably does n behave l a phosphoresc5t sulphide1 = example1 :i* c\ld be f9ely p[d]$ )\t impair+ ! phosphoresc5ce1 b r l p[d]$ ruby or diamond1 & !re=e x w\ld be necess>y1 9 ord] to make a decisive te/1 to obta9 x 9 a l>ge lump & poli% up ! surface4 ,if ! c>borundum proves useful 9 connection ) ^! & simil> exp]im5ts1 its *ief value w be f\nd 9 ! production ( coat+s1 ?9 conductors1 buttons1 or o!r electrodes capable ( )/&+ extremely high degrees ( heat4 ,! production ( a small electrode1 capable ( )/&+ enorm\s temp]atures1 ,i reg>d z ( ! greate/ importance 9 ! manufacture ( light4 ,x w\ld enable u to obta91 by means ( curr5ts ( v high frequ5cies1 c]ta9ly #bj times1 if n m1 ! quantity ( light :i* is obta9$ 9 ! pres5t inc&esc5t lamp by ! same exp5diture ( en]gy4 ,?is e/imate may appe> to _m exagg]at$1 b 9 reality ,i ?9k x is f> f be+ s4 ,z ?is /atem5t might be misund]/ood1 ,i ?9k x is necess>y to expose cle>ly ! problem ) :i*1 9 ?is l9e ( "w1 we are confront$1 & ! mann] 9 :i*1 9 my op9ion1 a solution w be arriv$ at4 ,any "o :o beg9s a /udy ( ! problem w be apt to ?9k t :at is want$ 9 a lamp ) an electrode is a v high degree ( inc&esc5ce ( ! electrode4 ,!re he w be mi/ak54 ,! high inc&esc5ce ( ! button is a necess>y evil1 b :at is really want$ is ! high inc&esc5ce ( ! gas surr\nd+ ! button4 ,9 o!r words1 ! problem 9 su* a lamp is to br+ a mass ( gas to ! highe/ possible inc&esc5ce4 ,! high] ! inc&esc5ce1 ! quick] ! mean vibration1 ! great] is ! economy ( ! light production4 ,b to ma9ta9 a mass ( gas at a high degree ( inc&esc5ce 9 a glass vessel1 x w always be necess>y to keep ! inc&esc5t mass away f ! glass2 t is1 to conf9e x z mu* z possible to ! c5tral portion ( ! globe4 ,9 "o ( ! exp]im5ts ?is ev5+ a bru% 0 produc$ at ! end ( a wire4 ,! bru% 0 a flame1 a s\rce ( heat & light4 ,x did n emit mu* p]ceptible heat1 nor did x gl[ ) an int5se light2 b is x ! less a flame because x does n scor* my h&8 ,is x ! less a flame because x does n hurt my eyes by its brilliancy8 ,! problem is precisely to produce 9 ! bulb su* a flame1 mu* small] 9 size1 b incomp>ably m p[]ful4 ,7 !re means at h& = produc+ electric impulses ( a suffici5tly high frequ5cy1 & = transmitt+ !m1 ! bulb c\ld be done away )1 unless x 7 us$ to protect ! electrode1 or to economize ! en]gy by conf9+ ! heat4 ,b z su* means are n at disposal1 x becomes necess>y to place ! t]m9al 9 ! bulb & r>efy ! air 9 ! same4 ,?is is done m]ely to enable ! app>atus to p]=m ! "w :i* x is n capable ( p]=m+ at ord9>y air pressure4 ,9 ! bulb we are able to int5sify ! action to any degree--s f> t ! bru% emits a p[]ful light4 ,! int5sity ( ! light emitt$ dep5ds pr9cipally on ! frequ5cy & pot5tial ( ! impulses1 & on ! electric d5sity on ! surface ( ! electrode4 ,x is ( ! greate/ importance to employ ! smalle/ possible button1 9 ord] to pu% ! d5sity v f>4 ,"u ! viol5t impact ( ! molecules ( ! gas surr\nd+ x1 ! small electrode is ( c\rse br\ght to an extremely high temp]ature1 b ar\nd x is a mass ( highly inc&esc5t gas1 a flame photosph]e1 _m hundr$ times ! volume ( ! electrode4 ,) a diamond1 c>borundum or zirconia button ! photosph]e c be z mu* z "o ?\s& times ! volume ( ! button4 ,)\t mu* reflection "o w\ld ?9k t 9 pu%+ s f> ! inc&esc5ce ( ! electrode x w\ld be in/antly volatiliz$4 ,b aft] a c>eful consid]ation "o w\ld f9d t1 !oretically1 x %\ld n occur1 & 9 ?is fact--:i*1 moreov]1 is exp]im5tally demon/rat$--lies pr9cipally ! future value ( su* a lamp4 ,at fir/1 :5 ! bomb>dm5t beg9s1 mo/ ( ! "w is p]=m$ on ! surface ( ! button1 b :5 a highly conduct+ photosph]e is =m$ ! button is comp>atively reliev$4 ,! high] ! inc&esc5ce ( ! photosph]e1 ! m x approa*es 9 conductivity to t ( ! electrode1 & ! m1 !re=e1 ! solid & ! gas =m "o conduct+ body4 ,! consequ5ce is t ! fur!r ! inc&esc5ce is =c$ ! m "w1 comp>atively1 is p]=m$ on ! gas1 & ! less on ! electrode4 ,! =mation ( a p[]ful photosph]e is consequ5tly ! v means = protect+ ! electrode4 ,?is protection1 ( c\rse1 is a relative "o1 & x %\ld n be ?\ght t by pu%+ ! inc&esc5ce high] ! electrode is actually less det]iorat$4 ,/ill1 !oretically1 ) extreme frequ5cies1 ?is result mu/ be rea*$1 b probably at a temp]ature too high = mo/ ( ! refractory bodies kn[n4 ,giv51 !n1 an electrode :i* c )/& to a v high limit ! effect ( ! bomb>dm5t & outw>d /ra91 x w\ld be safe1 no matt] h[ mu* x 0 =c$ beyond t limit4 ,9 an inc&esc5t lamp q diff]5t consid]ations apply4 ,!re ! gas is n at all conc]n$2 ! :ole ( ! "w is p]=m$ on ! filam5t2 & ! life ( ! lamp dim9i%es s rapidly ) ! increase ( ! degree ( inc&esc5ce t economical reasons compel u to "w x at a l[ inc&esc5ce4 ,b if an inc&esc5t lamp is op]at$ ) curr5ts ( v high frequ5cy1 ! action ( ! gas _c be neglect$1 & ! rules = ! mo/ economical work+ mu/ be consid]ably modifi$4 ,9 ord] to br+ su* a lamp ) "o or two electrodes to a great p]fection1 x is necess>y to employ impulses ( v high frequ5cy4 ,! high frequ5cy secures1 among o!rs1 two *ief advantages1 :i* h a mo/ important be>+ ^u ! economy ( ! light production4 ,fir/1 ! det]ioration ( ! electrode is r$uc$ by reason ( ! fact t we employ a great _m small impacts1 in/ead ( a few viol5t ones1 :i* quickly %att] ! /ructure2 secondly1 ! =mation ( a l>ge photosph]e is facilitat$4 ,9 ord] to r$uce ! det]ioration ( ! electrode to ! m9imum1 x is desirable t ! vibration be h>monic1 = any sudd5ness ha/5s ! process ( de/ruction4 ,an electrode la/s mu* long] :5 kept at inc&esc5ce by curr5ts1 or impulses1 obta9$ f a high frequ5cy alt]nator1 :i* rise & fall m or less h>monically1 ?an by impulses obta9$ f a disruptive dis*>ge coil4 ,9 ! latt] case !re is no d\bt t mo/ ( ! damage is done by ! fundam5tal sudd5 dis*>ges4 ,"o ( ! elem5ts ( loss 9 su* a lamp is ! bomb>dm5t ( ! globe4 ,z ! pot5tial is v high1 ! molecules are project$ ) great spe$2 !y /rike ! glass1 & usually excite a /rong phosphoresc5ce4 ,! effect produc$ is v pretty1 b = economical reasons x w\ld be p]haps pref]able to prev5t1 or at lea/ r$uce to a m9imum1 ! bomb>dm5t aga9/ ! globe1 z 9 su* case x is1 z a rule1 n ! object to excite phosphoresc5ce1 & z "s loss ( en]gy results f ! bomb>dm5t4 ,?is loss 9 ! bulb is pr9cipally dep5d5t on ! pot5tial ( ! impulses & on ! electric d5sity on ! surface ( ! electrode4 ,9 employ+ v high frequ5cies ! loss ( en]gy by ! bomb>dm5t is greatly r$uc$1 =1 fir/1 ! pot5tial ne$$ to p]=m a giv5 am\nt ( "w is mu* small]2 &1 secondly1 by produc+ a highly conduct+ photosph]e ar\nd ! electrode1 ! same result is obta9$ z ?\gh ! electrode 7 mu* l>g]1 :i* is equival5t to a small] electric d5sity4 ,b be x by ! dim9ution ( ! maximum pot5tial or ( ! d5sity1 ! ga9 is effect$ 9 ! same mann]1 namely1 by avoid+ viol5t %ocks1 :i* /ra9 ! glass mu* beyond its limit ( ela/icity4 ,if ! frequ5cy c\ld be br\ght high en\gh1 ! loss due to ! imp]fect ela/icity ( ! glass w\ld be entirely negligible4 ,! loss due to bomb>dm5t ( ! globe may1 h[ev]1 be r$uc$ by us+ two electrodes in/ead ( "o4 ,9 su* case ea* ( ! electrodes may be connect$ to "o ( ! t]m9als2 or else1 if x is pref]able to use only "o wire1 "o electrode may be connect$ to "o t]m9al & ! o!r to ! gr\nd or to an insulat$ body ( "s surface1 z1 = in/ance1 a %ade on ! lamp4 ,9 ! latt] case1 unless "s judgm5t is us$1 "o ( ! electrodes might gl[ m int5sely ?an ! o!r4 ,b on ! :ole ,i f9d x pref]able1 :5 us+ su* high frequ5cies1 to employ only "o electrode & "o connect+ wire4 ,i am conv9c$ t ! illum9at+ device ( ! ne> future w n require = its op]ation m ?an "o lead1 &1 at any rate1 x w h no lead+-9 wire1 s9ce ! en]gy requir$ c be z well transmitt$ ?r\gh ! glass4 ,9 exp]im5tal bulbs ! lead+-9 wire is n g5]ally us$ on acc\nt ( conv5i5ce1 z 9 employ+ cond5s] coat+s 9 ! mann] indicat$ 9 ,fig4 #aea1 = example1 !re is "s difficulty 9 fitt+ ! p>ts1 b ^! difficulties w\ld n exi/ if a great _m bulbs 7 manufactur$2 o!rwise ! en]gy c be convey$ ?r\gh ! glass z well z ?r\gh a wire1 & ) ^! high frequ5cies ! losses are v small4 ,su* illu/rat+ devices w necess>ily involve ! use ( v high pot5tials1 & ?is1 9 ! eyes ( practical m51 might be an objectionable feature4 ,yet1 9 reality1 high pot5tials are n objectionable--c]ta9ly n 9 ! lea/ s f> z ! safety ( ! devices is conc]n$4 ,!re are two ways ( r5d]+ an electric appliance safe4 ,"o is to use l[ pot5tials1 ! o!r is to det]m9e ! dim5sions ( ! app>atus s t x is safe1 no matt] h[ high a pot5tial is us$4 ,( ! two1 ! latt] seems to me ! bett] way1 = !n ! safety is absolute1 unaffect$ by any possible comb9ation ( circum/ances :i* might r5d] ev5 a l[-pot5tial appliance dang]\s to life & prop]ty4 ,b ! practical conditions require n only ! judici\s det]m9ation ( ! dim5sions ( ! app>atus2 !y likewise necessitate ! employm5t ( en]gy ( ! prop] k9d4 ,x is easy1 = in/ance1 to con/ruct a trans=m] capable ( giv+1 :5 op]at$ f an ord9>y alt]nate curr5t ma*9e ( l[ t5sion1 say #ej1jjj volts1 :i* might be requir$ to light a highly exhau/$ phosphoresc5t tube1 s t1 9 spite ( ! high pot5tial1 x is p]fectly safe1 ! %ock f x produc+ no inconv5i5ce4 ,/ill su* a trans=m] w\ld be exp5sive1 & 9 itself ineffici5t2 &1 besides1 :at en]gy 0 obta9$ f x w\ld n be economically us$ = ! production ( light4 ,! economy dem&s ! employm5t ( en]gy 9 ! =m ( extremely rapid vibrations4 ,! problem ( produc+ light has be5 lik5$ to t ( ma9ta9+ a c]ta9 high-pit* note by means ( a bell4 ,x %\ld be said a b>ely audible note2 & ev5 ^! words w\ld n express x1 s wond]ful is ! s5sitiv5ess ( ! eye4 ,we may deliv] p[]ful bl[s at long int]vals1 wa/e a good deal ( en]gy1 & /ill n get :at we want2 or we may keep up ! note by deliv]+ frequ5t taps1 & get ne>] to ! object s\ght by ! exp5diture ( mu* less en]gy4 ,9 ! production ( light1 z f> z ! illum9at+ device is conc]n$1 !re c be only "o rule--t is1 to use z high frequ5cies z c be obta9$2 b ! means = ! production & conveyance ( impulses ( su* "* impose1 at pres5t at lea/1 great limitations4 ,once x is decid$ to use v high frequ5cies1 ! return wire becomes unnecess>y1 & all ! appliances are simplifi$4 ,by ! use ( obvi\s means ! same result is obta9$ z ?\gh ! return wire 7 us$4 ,x is suffici5t = ?is purpose to br+ 9 contact ) ! bulb1 or m]ely 9 ! vic9ity ( ! same1 an insulat$ body ( "s surface4 ,! surface ne$1 ( c\rse1 be ! small]1 ! high] ! frequ5cy & pot5tial us$1 & necess>ily1 also1 ! high] ! economy ( ! lamp or o!r device4 ,?is plan ( work+ has be5 resort$ to on sev]al occasions ?is ev5+4 ,s1 = in/ance1 :5 ! inc&esc5ce ( a button 0 produc$ by grasp+ ! bulb ) ! h&1 ! body ( ! exp]im5t] m]ely s]v$ to int5sify ! action4 ,! bulb us$ 0 simil> to t illu/rat$ 9 ,fig4 #adh1 & ! coil 0 excit$ to a small pot5tial1 n suffici5t to br+ ! button to inc&esc5ce :5 ! bulb 0 hang+ f ! wire2 & incid5tally1 9 ord] to p]=m ! exp]im5t 9 a m suitable mann]1 ! button 0 tak5 s l>ge t a p]ceptible "t _h to elapse be=e1 ^u grasp+ ! bulb1 x c\ld be r5d]$ inc&esc5t4 ,! contact ) ! bulb 01 ( c\rse1 q unnecess>y4 ,x is easy1 by us+ a r l>ge bulb ) an exce$+ly small electrode1 to adju/ ! conditions s t ! latt] is br\ght to bright inc&esc5ce by ! m]e approa* ( ! exp]im5t] )9 a few feet ( ! bulb1 & t ! inc&esc5ce subsides ^u 8 rec$+4 ,illu/ration3 ,,fig4 #aec4 ,illu/ration3 ,,fig4 #aed4 ,9 ano!r exp]im5t1 :5 phosphoresc5ce 0 excit$1 a simil> bulb 0 us$4 ,"h aga91 orig9ally1 ! pot5tial 0 n suffici5t to excite phosphoresc5ce until ! action 0 int5sifi$--9 ?is case1 h[ev]1 to pres5t a diff]5t feature1 by t\*+ ! socket ) a metallic object held 9 ! h&4 ,! electrode 9 ! bulb 0 a c>bon button s l>ge t x c\ld n be br\ght to inc&esc5ce1 & !reby spoil ! effect produc$ by phosphoresc5ce4 ,aga91 9 ano!r ( ! e>ly exp]im5ts1 a bulb 0 us$1 z illu/rat$ 9 ,fig4 #ada4 ,9 ?is in/ance1 by t\*+ ! bulb ) "o or two f+]s1 "o or two %ad[s ( ! /em inside 7 project$ aga9/ ! glass1 ! t\* ( ! f+] produc+ ! same results z ! application ( an ext]nal negative electrode "u ord9>y circum/ances4 ,9 all ^! exp]im5ts ! action 0 int5sifi$ by augm5t+ ! capacity at ! end ( ! lead connect$ to ! t]m9al4 ,z a rule1 x is n necess>y to resort to su* means1 & w\ld be q unnecess>y ) /ill high] frequ5cies2 b :5 x is desir$1 ! bulb1 or tube1 c be easily adapt$ to ! purpose4 ,9 ,fig4 #aec1 = example1 an exp]im5tal bulb1 ,l1 is %[n1 :i* is provid$ ) a neck1 n1 on ! top1 = ! application ( an ext]nal t9foil coat+1 :i* may be connect$ to a body ( l>g] surface4 ,su* a lamp z illu/rat$ 9 ,fig4 #aed may also be light$ by connect+ ! t9foil coat+ on ! neck n to ! t]m9al1 & ! lead+-9 wire1 w1 to an insulat$ plate4 ,if ! bulb /&s 9 a socket upright1 z %[n 9 ! cut1 a %ade ( conduct+ mat]ial may be slipp$ 9 ! neck1 n1 & ! action ?us magnifi$4 ,a m p]fect$ arrangem5t us$ 9 "s ( ^! bulbs is illu/rat$ 9 ,fig4 #aee4 ,9 ?is case ! con/ruction ( ! bulb is z %[n & describ$ be=e1 :5 ref]5ce 0 made to ,fig4 #adh4 ,a z9c %eet1 ,z1 ) a tubul> ext5sion1 ,t1 is appli$ ov] ! metallic socket1 ,s4 ,! bulb hangs d[nw>d f ! t]m9al1 t1 ! z9c %eet1 ,z1 p]=m+ ! d\ble (fice ( int5sifi] & reflector4 ,! reflector is sep>at$ f ! t]m9al1 t1 by an ext5sion ( ! insulat+ plug1 ,p4 ,a simil> disposition ) a phosphoresc5t tube is illu/rat$ 9 ,fig4 #aef4 ,! tube1 ,t1 is prep>$ f two %ort tubes ( diff]5t diamet]1 :i* are seal$ on ! ends4 ,on ! l[] end is plac$ an inside conduct+ coat+1 ,c1 :i* connects to ! wire w4 ,! wire has a hook on ! upp] end = susp5sion1 & passes ?r\gh ! c5tre ( ! inside tube1 :i* is fill$ ) "s good & tightly pack$ insulator4 ,on ! outside ( ! upp] end ( ! tube1 ,t1 is ano!r conduct+ coat+1 ,c#a1 ^u :i* is slipp$ a metallic reflector ,z1 :i* %\ld be sep>at$ by a ?ick insulation f ! end ( wire w4 ,! economical use ( su* a reflector or int5sifi] w\ld require t all en]gy suppli$ to an air cond5s] %\ld be recov]able1 or1 9 o!r words1 t !re %\ld n be any losses1 nei!r 9 ! gase\s m$ium nor ?r\gh its action else:]e4 ,?is is f> f be+ s1 b1 =tunately1 ! losses may be r$uc$ to any?+ desir$4 ,a few rem>ks are necess>y on ?is subject1 9 ord] to make ! exp]i5ces ga!r$ 9 ! c\rse ( ^! inve/igations p]fectly cle>4 ,illu/ration3 ,,fig4 #aee4 ,suppose a small helix ) _m well insulat$ turns1 z 9 exp]im5t ,fig4 #adf1 has "o ( its ends connect$ to "o ( ! t]m9als ( ! induction coil1 & ! o!r to a metal plate1 or1 = ! sake ( simplicity1 a sph]e1 insulat$ 9 space4 ,:5 ! coil is set to "w1 ! pot5tial ( ! sph]e is alt]nat$1 & a small helix n[ behaves z ?\gh its free end 7 connect$ to ! o!r t]m9al ( ! induction coil4 ,if an iron rod be held )9 a small helix1 x is quickly br\ght to a high temp]ature1 indicat+ ! passage ( a /rong curr5t ?r\gh ! helix4 ,h[ does ! insulat$ sph]e act 9 ?is case8 ,x c be a cond5s]1 /or+ & return+ ! en]gy suppli$ to x1 or x c be a m]e s9k ( en]gy1 & ! conditions ( ! exp]im5t det]m9e :e!r x is r "o ?an ! o!r4 ,! sph]e be+ *>g$ to a high pot5tial1 x acts inductively ^u ! surr\nd+ air1 or :atev] gase\s m$ium !re might be4 ,! molecules1 or atoms1 :i* are ne> ! sph]e1 are ( c\rse m attract$1 & move ?r\gh a great] di/ance ?an ! f>!r ones4 ,:5 ! ne>e/ molecules /rike ! sph]e1 !y are repell$1 & collisions occur at all di/ances )9 ! inductive action ( ! sph]e4 ,x is n[ cle> t1 if ! pot5tial be /eady1 b little loss ( en]gy c be caus$ 9 ?is way1 = ! molecules :i* are ne>e/ to ! sph]e1 hav+ _h an additional *>ge imp>t$ to !m by contact1 are n attract$ until !y h p>t$1 if n ) all1 at lea/ ) mo/ ( ! additional *>ge1 :i* c be accompli%$ only aft] a great _m collisions4 ,f ! fact1 t ) a /eady pot5tial !re is b little loss 9 dry air1 "o mu/ come to su* a conclusion4 ,:5 ! pot5tial ( a sph]e1 in/ead ( be+ /eady1 is alt]nat+1 ! conditions are entirely diff]5t4 ,9 ?is case a rhy?mical bomb>dm5t occurs1 no matt] :e!r ! molecules1 aft] com+ 9 contact ) ! sph]e1 lose ! imp>t$ *>ge or n2 :at is m1 if ! *>ge is n lo/1 ! impacts are only ! m viol5t4 ,/ill1 if ! frequ5cy ( ! impulses be v small1 ! loss caus$ by ! impacts & collisions w\ld n be s]i\s1 unless ! pot5tial 7 excessive4 ,b :5 extremely high frequ5cies & m or less high pot5tials are us$1 ! loss may v great4 ,! total en]gy lo/ p] unit ( "t is proportionate to ! product ( ! numb] ( impacts p] second1 or ! frequ5cy & ! en]gy lo/ 9 ea* impact4 ,b ! en]gy ( an impact mu/ be proportionate to ! squ>e ( ! electric d5sity ( ! sph]e1 s9ce ! *>ge imp>t$ to ! molecule is proportionate to t d5sity4 ,i conclude f ?is t ! total en]gy lo/ mu/ be proportionate to ! product ( ! frequ5cy & ! squ>e ( ! electric d5sity2 b ?is law ne$s exp]im5tal confirmation4 ,assum+ ! prec$+ consid]ations to be true1 !n1 by rapidly alt]nat+ ! pot5tial ( a body imm]s$ 9 an insulat+ gase\s m$ium1 any am\nt ( en]gy may be dissipat$ into space4 ,mo/ ( t en]gy !n1 ,i believe1 is n dissipat$ 9 ! =m ( long e!r waves1 propagat$ to consid]able di/ance1 z is ?\ght mo/ g5]ally1 b is consum$--9 ! case ( an insulat$ sph]e1 = example--9 impact & collisional losses--t is1 heat vibrations--on ! surface & 9 ! vic9ity ( ! sph]e4 ,to r$uce ! dissipation1 x is necess>y to "w ) a small electric d5sity--! small]1 ! high] ! frequ5cy4 ,illu/ration3 ,,fig4 #aef4 ,b s9ce1 on ! assumption be=e made1 ! loss is dim9i%$ ) ! squ>e ( ! d5sity1 & s9ce curr5ts ( v high frequ5cies involve consid]able wa/e :5 transmitt$ ?r\gh conductors1 x foll[s t1 on ! :ole1 x is bett] to employ "o wire ?an two4 ,!re=e1 if motors1 lamps1 or devices ( any k9d are p]fect$1 capable ( be+ advantage\sly op]at$ by curr5ts ( extremely high frequ5cy1 economical reasons w make x advisable to use only "o wire1 especially if ! di/ances are great4 ,:5 en]gy is absorb$ 9 a cond5s]1 ! same behaves z ?\gh its capacity 7 increas$4 ,absorption always exi/s m or less1 b g5]ally x is small & ( no consequ5ce z long z ! frequ5cies are n v great4 ,9 us+ extremely high frequ5cies1 &1 necess>ily 9 su* case1 also high pot5tials1 ! absorption--or1 :at is "h meant m p>ticul>ly by ?is t]m1 ! loss ( en]gy due to ! pres5ce ( a gase\s m$ium--is an important factor to be consid]$1 z ! en]gy absorb$ 9 ! air cond5s] may be any fraction ( ! suppli$ en]gy4 ,?is w\ld seem to make x v difficult to tell f ! measur$ or comput$ capacity ( an air cond5s] its actual capacity or vibration p]iod1 especially if ! cond5s] is ( v small surface & is *>g$ to a v high pot5tial4 ,z _m important results are dep5d5t ^u ! correctness ( ! e/imation ( ! vibration p]iod1 ?is subject dem&s ! mo/ c>eful scrut9y ( o!r inve/igators4 ,to r$uce ! probable error z mu* z possible 9 exp]im5ts ( ! k9d allud$ to1 x is advisable to use sph]es or plates ( l>ge surface1 s z to make ! d5sity exce$+ly small4 ,o!rwise1 :5 x is practicable1 an oil cond5s] %\ld be us$ 9 pref]5ce4 ,9 oil or o!r liquid dielectrics !re are seem+ly no su* losses z 9 gase\s m$ia4 ,x be+ impossible to exclude entirely ! gas 9 cond5s]s ) solid dielectrics1 su* cond5s]s %\ld be imm]s$ 9 oil1 = economical reasons1 if no?+ else2 !y c !n be /ra9$ to ! utmo/1 & w rema9 cool4 ,9 ,leyd5 j>s ! loss due to air is comp>atively small1 z ! t9foil coat+s are l>ge1 close toge!r1 & ! *>g$ surfaces n directly expos$2 b :5 ! pot5tials are v high1 ! loss may be m or less consid]able at1 or ne>1 ! upp] edge ( ! foil1 :]e ! air is pr9cipally act$ ^u4 ,if ! j> be imm]s$ 9 boil$-out oil1 x w be capable ( p]=m+ f\r times ! am\nt ( "w :i* x c = any l5g? ( "t :5 us$ 9 ! ord9>y way1 & ! loss w be inappreciable4 ,x %\ld n be ?\ght t ! loss 9 heat 9 an air cond5s] is necess>ily associat$ ) ! =mation ( visible /reams or bru%es4 ,if a small electrode1 inclos$ 9 an unexhau/$ bulb1 is connect$ to "o ( ! t]m9als ( ! coil1 /reams c be se5 to issue f ! electrode1 & ! air 9 ! bulb is heat$2 if in/ead ( a small electrode a l>ge sph]e is inclos$ 9 ! bulb1 no /reams are obs]v$1 /ill ! air is heat$4 ,nor %\ld x be ?\ght t ! temp]ature ( an air cond5s] w\ld give ev5 an approximate idea ( ! loss 9 heat incurr$1 z 9 su* case heat mu/ be giv5 (f mu* m quickly1 s9ce !re is1 9 addition to ! ord9>y radiation1 a v active c>ry+ away ( heat by indep5d5t c>ri]s go+ on1 & s9ce n only ! app>atus1 b ! air at "s di/ance f x is heat$ 9 consequ5ce ( ! collisions :i* mu/ occur4 ,ow+ to ?is1 9 exp]im5ts ) su* a coil1 a rise ( temp]ature c be di/9ctly obs]v$ only :5 ! body connect$ to ! coil is v small4 ,b ) app>atus on a l>g] scale1 ev5 a body ( consid]able bulk w\ld be heat$1 z1 = in/ance1 ! body ( a p]son2 & ,i ?9k t skill$ physicians might make obs]vations ( utility 9 su* exp]im5ts1 :i*1 if ! app>atus 7 judici\sly design$1 w\ld n pres5t ! slighte/ dang]4 ,a "q ( "s int]e/1 pr9cipally to meteorologi/s1 pres5ts itself "h4 ,h[ does ! e>? behave8 ,! e>? is an air cond5s]1 b is x a p]fect or a v imp]fect "o--a m]e s9k ( en]gy8 ,!re c be little d\bt t to su* small di/urbance z might be caus$ 9 an exp]im5t1 ! e>? behaves z an almo/ p]fect cond5s]4 ,b x might be diff]5t :5 its *>ge is set 9 vibration by "s sudd5 di/urbance occurr+ 9 ! heav5s4 ,9 su* case1 z be=e /at$1 probably only little ( ! en]gy ( ! vibrations set up w\ld be lo/ into space 9 ! =m ( long e!r radiations1 b mo/ ( ! en]gy1 ,i ?9k1 w\ld sp5d itself 9 molecul> impacts & collisions1 & pass (f into space 9 ! =m ( %ort heat1 & possibly light1 waves4 ,z bo? ! frequ5cy ( ! vibrations ( ! *>ge & ! pot5tial are 9 all probability excessive1 ! en]gy conv]t$ into heat may be consid]able4 ,s9ce ! d5sity mu/ be unev5ly di/ribut$1 ei!r 9 consequ5ce ( ! irregul>ity ( ! e>?'s surface1 or on acc\nt ( ! condition ( ! atmosph]e 9 v>i\s places1 ! effect produc$ w\ld accord+ly v>y f place to place4 ,consid]able v>iations 9 ! temp]ature & pressure ( ! atmosph]e may 9 ?is mann] be caus$ at any po9t ( ! surface ( ! e>?4 ,! v>iations may be gradual or v sudd51 accord+ to ! nature ( ! g5]al di/urbance1 & may produce ra9 & /orms1 or locally modify ! wea!r 9 any way4 ,f ! rem>ks be=e made1 "o may see :at an important factor ( loss ! air 9 ! neighborhood ( a *>g$ surface becomes :5 ! electric d5sity is great & ! frequ5cy ( ! impulses excessive4 ,b ! action1 z expla9$1 implies t ! air is insulat+--t is1 t x is compos$ ( indep5d5t c>ri]s imm]s$ 9 an insulat+ m$ium4 ,?is is ! case only :5 ! air is at some?+ l ord9>y or great]1 or at extremely small1 pressure4 ,:5 ! air is slightly r>efi$ & conduct+1 !n true conduction losses occur also4 ,9 su* case1 ( c\rse1 consid]able en]gy may be dissipat$ into space ev5 ) a /eady pot5tial1 or ) impulses ( l[ frequ5cy1 if ! d5sity is v great4 ,:5 ! gas is at v l[ pressure1 an electrode is heat$ m because high] spe$s c be rea*$4 ,if ! gas ar\nd ! electrode is /rongly compress$1 ! displacem5ts1 & consequ5tly ! spe$s1 are v small1 & ! heat+ is insignificant4 ,b if 9 su* case ! frequ5cy c\ld be suffici5tly increas$1 ! electrode w\ld be br\ght to a high temp]ature z well z if ! gas 7 at v l[ pressure2 9 fact1 exhau/+ ! bulb is only necess>y because we _c produce1 7& possibly n convey7 curr5ts ( ! requir$ frequ5cy4 ,return+ to ! subject ( electrode lamps1 x is obvi\sly ( advantage 9 su* a lamp to conf9e z mu* z possible ! heat to ! electrode by prev5t+ ! circulation ( ! gas 9 ! bulb4 ,if a v small bulb be tak51 x w\ld conf9e ! heat bett] ?an a l>ge "o1 b x might n be ( suffici5t capacity to be op]at$ f ! coil1 or1 if s1 ! glass might get too hot4 ,a simple way to improve 9 ?is direction is to employ a globe ( ! requir$ size1 b to place a small bulb1 ! diamet] ( :i* is prop]ly e/imat$1 ov] ! refractory button conta9$ 9 ! globe4 ,?is arrangem5t is illu/rat$ 9 ,fig4 #aeg4 ,illu/ration3 ,,fig4 #aeg4 ,illu/ration3 ,,fig4 #aeh4 ,! globe ,l has 9 ?is case a l>ge neck n1 all[+ ! small bulb b to slip ?r\gh4 ,o!rwise ! con/ruction is ! same z %[n 9 ,fig4 #adg1 = example4 ,! small bulb is conv5i5tly support$ ^u ! /em s1 c>ry+ ! refractory button m4 ,x is sep>at$ f ! alum9um tube a by sev]al lay]s ( mica ,m1 9 ord] to prev5t ! crack+ ( ! neck by ! rapid heat+ ( ! alum9um tube ^u a sudd5 turn+ on ( ! curr5t4 ,! inside bulb %\ld be z small z possible :5 x is desir$ to obta9 light only by inc&esc5ce ( ! electrode4 ,if x is desir$ to produce phosphoresc5ce1 ! bulb %\ld be l>g]1 else x w\ld be apt to get too hot1 & ! phosphoresc5ce w\ld cease4 ,9 ?is arrangem5t usually only ! small bulb %[s phosphoresc5ce1 z !re is practically no bomb>dm5t aga9/ ! out] globe4 ,9 "s ( ^! bulbs con/ruct$ z illu/rat$ 9 ,fig4 #aeg1 ! small tube 0 coat$ ) phosphoresc5t pa9t1 & beautiful effects 7 obta9$4 ,in/ead ( mak+ ! inside bulb l>ge1 9 ord] to avoid undue heat+1 x answ]s ! purpose to make ! electrode m l>g]4 ,9 ?is case ! bomb>dm5t is weak5$ by reason ( ! small] electric d5sity4 ,_m bulbs 7 con/ruct$ on ! plan illu/rat$ 9 ,fig4 #aeh4 ,"h a small bulb b1 conta9+ ! refractory button m1 ^u be+ exhau/$ to a v high degree 0 seal$ 9 a l>ge globe ,l1 :i* 0 !n mod]ately exhau/$ & seal$ (f4 ,! pr9cipal advantage ( ?is con/ruction 0 t x all[$ ( rea*+ extremely high vacua1 &1 at ! same "t ( us+ a l>ge bulb4 ,x 0 f\nd1 9 ! c\rse ( exp]im5ts ) bulbs su* z illu/rat$ 9 ,fig4 #aeh1 t x 0 well to make ! /em s1 ne> ! seal at e1 v ?ick1 & ! lead+-9 wire w ?91 z x occurr$ sometimes t ! /em at e 0 heat$ & ! bulb 0 crack$4 ,(t5 ! out] globe ,l 0 exhau/$ only j en\gh to all[ ! dis*>ge to pass ?r\gh1 & ! space betwe5 ! bulbs appe>$ crimson1 produc+ a curi\s effect4 ,9 "s cases1 :5 ! exhau/ion 9 globe ,l 0 v l[1 & ! air good conduct+1 x 0 f\nd necess>y1 9 ord] to br+ ! button m to high inc&esc5ce1 to place1 pref]ably on ! upp] "p ( ! neck ( ! globe1 a t9foil coat+ :i* 0 connect$ to an insulat$ body1 to ! gr\nd1 or to ! o!r t]m9al ( ! coil1 z ! highly conduct+ air weak5$ ! effect some:at1 probably by be+ act$ ^u inductively f ! wire w1 :]e x ent]$ ! bulb at e4 ,ano!r difficulty--:i*1 h[ev]1 is always pres5t :5 ! refractory button is m\nt$ 9 a v small bulb--exi/$ 9 ! con/ruction illu/rat$ 9 ,fig4 #aeh1 namely1 ! vacuum 9 ! bulb b w\ld be impair$ 9 a comp>atively %ort "t4 ,! *ief idea 9 ! two la/ describ$ con/ructions 0 to conf9e ! heat to ! c5tral portion ( ! globe by prev5t+ ! ex*ange ( air4 ,an advantage is secur$1 b ow+ to ! heat+ ( ! inside bulb & sl[ evaporation ( ! glass1 ! vacuum is h>d to ma9ta91 ev5 if ! con/ruction illu/rat$ 9 ,fig4 #aeg be *os51 9 :i* bo? bulbs communicate4 ,b by f> ! bett] way--! ideal way--w\ld be to rea* suffici5tly high frequ5cies4 ,! high] ! frequ5cy1 ! sl[] w\ld be ! ex*ange ( ! air1 & ,i ?9k t a frequ5cy may be rea*$1 at :i* !re w\ld be no ex*ange :atev] ( ! air molecules ar\nd ! t]m9al4 ,we w\ld !n produce a flame 9 :i* !re w\ld be no c>ry+ away ( mat]ial1 & a que] flame x w\ld be1 = x w\ld be rigid6 ,) su* high frequ5cies ! in]tia ( ! p>ticles w\ld come into play4 ,z ! bru%1 or flame1 w\ld ga9 rigidity 9 virtue ( ! in]tia ( ! p>ticles1 ! ex*ange ( ! latt] w\ld be prev5t$4 ,?is w\ld necess>ily occur1 =1 ! numb] ( impulses be+ augm5t$1 ! pot5tial en]gy ( ea* w\ld dim9i%1 s t f9ally only atomic vibrations c\ld be set up1 & ! motion ( translation ?r\gh measurable space w\ld cease4 ,?us an ord9>y gas burn] connect$ to a s\rce ( rapidly alt]nat+ pot5tial might h its effici5cy augm5t$ to a c]ta9 limit1 & ?is = two reasons--because ( ! additional vibration imp>t$1 & because ( a sl[+ d[n ( ! process ( c>ry+ (f4 ,b ! r5ewal be+ r5d]$ difficult1 a r5ewal be+ necess>y to ma9ta9 ! burn]1 a cont9u$ increase ( ! frequ5cy ( ! impulses1 assum+ !y c\ld be transmitt$ to & impress$ ^u ! flame1 w\ld result 9 ! ext9ction ( ! latt]1 mean+ by ?is t]m only ! cessation ( ! *emical process4 ,i ?9k1 h[ev]1 t 9 ! case ( an electrode imm]s$ 9 a fluid insulat+ m$ium1 & surr\nd$ by indep5d5t c>ri]s ( electric *>ges1 :i* c be act$ ^u inductively1 a suffici5t high frequ5cy ( ! impulses w\ld probably result 9 a gravitation ( ! gas all ar\nd t[>d ! electrode4 ,= ?is x w\ld be only necess>y to assume t ! indep5d5t bodies are irregul>ly %ap$2 !y w\ld !n turn t[>d ! electrode _! side ( ! greate/ electric d5sity1 & ?is w\ld be a position 9 :i* ! fluid resi/ance to approa* w\ld be small] ?an t (f]$ to ! rec$+4 ,! g5]al op9ion1 ,i d n d\bt1 is t x is out ( ! "q to rea* any su* frequ5cies z might--assum+ "s ( ! views be=e express$ to be true--produce any ( ! results :i* ,i h po9t$ out z m]e possibilities4 ,?is may be s1 b 9 ! c\rse ( ^! inve/igations1 f ! obs]vation ( _m ph5om5a1 ,i h ga9$ ! conviction t ^! frequ5cies w\ld be mu* l[] ?an "o is apt to e/imate at fir/4 ,9 a flame we set up light vibrations by caus+ molecules1 or atoms1 to collide4 ,b :at is ! ratio ( ! frequ5cy ( ! collisions & t ( ! vibrations set up8 ,c]ta9ly x mu/ be incomp>ably small] ?an t ( ! /rokes ( ! bell & ! s\nd vibrations1 or t ( ! dis*>ges & ! oscillations ( ! cond5s]4 ,we may cause ! molecules ( ! gas to collide by ! use ( alt]nate electric impulses ( high frequ5cy1 & s we may imitate ! process 9 a flame2 & f exp]im5ts ) frequ5cies :i* we are n[ able to obta91 ,i ?9k t ! result is producible ) impulses :i* are transmissible ?r\gh a conductor4 ,9 connection ) ?\ghts ( a simil> nature1 x appe>$ to me ( great int]e/ to demon/rate ! rigidity ( a vibrat+ gase\s column4 ,al?\gh ) su* l[ frequ5cies z1 say #aj1jjj p] second1 :i* ,i 0 able to obta9 )\t difficulty f a specially con/ruct$ alt]nator1 ! task look$ disc\rag+ at fir/1 ,i made a s]ies ( exp]im5ts4 ,! trials ) air at ord9>y pressure l$ to no result1 b ) air mod]ately r>efi$ ,i obta9 :at ,i ?9k to be an unmi/akable exp]im5tal evid5ce ( ! prop]ty s\ght =4 ,z a result ( ?is k9d might lead able inve/igators to conclusions ( importance1 ,i w describe "o ( ! exp]im5ts p]=m$4 ,x is well kn[n t :5 a tube is slightly exhau/$1 ! dis*>ge may be pass$ ?r\gh x 9 ! =m ( a ?9 lum9\s ?read4 ,:5 produc$ ) curr5ts ( l[ frequ5cy1 obta9$ f a coil op]at$ z usual1 ?is ?read is in]t4 ,if a magnet be approa*$ to x1 ! "p ne> ! same is attract$ or repell$1 accord+ to ! direction ( ! l9es ( =ce ( ! magnet4 ,x occurr$ to me t if su* a ?read w\ld be produc$ ) curr5ts ( v high frequ5cy1 x %\ld be m or less rigid1 & z x 0 visible x c\ld be easily /udi$4 ,accord+ly ,i prep>$ a tube ab\t "o in* 9 diamet] & "o metre long1 ) outside coat+ at ea* end4 ,! tube 0 exhau/$ to a po9t at :i*1 by a little work+1 ! ?read dis*>ge c\ld be obta9$4 ,x mu/ be rem>k$ "h t ! g5]al aspect ( ! tube1 & ! degree ( exhau/ion1 are q o!r ?an :5 ord9>y l[ frequ5cy curr5ts are us$4 ,z x 0 f\nd pref]able to "w ) "o t]m9al1 ! tube prep>$ 0 susp5d$ f ! end ( a wire connect$ to ! t]m9al1 ! t9foil coat+ be+ connect$ to ! wire1 & to ! l[] coat+ sometimes a small insulat$ plate 0 atta*$4 ,:5 ! ?read 0 =m$1 x ext5d$ ?r\gh ! upp] "p ( ! tube & lo/ itself 9 ! l[] end4 ,if x possess$ rigidity x resembl$1 n exactly an ela/ic cord /ret*$ tight betwe5 two supports1 b a cord susp5d$ f a height ) a small weight atta*$ at ! end4 ,:5 ! f+] or a small magnet 0 approa*$ to ! upp] end ( ! lum9\s ?read1 x c\ld be br\ght locally out ( position by electro/atic or magnetic action2 & :5 ! di/urb+ object 0 v quickly remov$1 an analog\s result 0 produc$1 z ?\gh a susp5d$ cord w\ld be displac$ & quickly releas$ ne> ! po9t ( susp5sion4 ,9 do+ ?is ! lum9\s ?read 0 set 9 vibration1 & two v %>ply m>k$ nodes1 & a ?ird indi/9ct "o1 7 =m$4 ,! vibration1 once set up1 cont9u$ = fully eight m9utes1 dy+ gradually out4 ,! spe$ ( ! vibration (t5 v>i$ p]ceptibly1 & x c\ld be obs]v$ t ! electro/atic attraction ( ! glass affect$ ! vibrat+ ?read2 b x 0 cle> t ! electro/atic action 0 n ! cause ( ! vibration1 = ! ?read 0 mo/ g5]ally /ation>y1 & c\ld always be set 9 vibration by pass+ ! f+] quickly ne> ! upp] "p ( ! tube4 ,) a magnet ! ?read c\ld be split 9 two & bo? p>ts vibrat$4 ,by approa*+ ! h& to ! l[] coat+ ( ! tube1 or insulation plate if atta*$1 ! vibration 0 quick5$2 also1 z f> z ,i c\ld see1 by rais+ ! pot5tial or frequ5cy4 ,?us1 ei!r increas+ ! frequ5cy or pass+ a /rong] dis*>ge ( ! same frequ5cy correspond$ to a tight5+ ( ! cord4 ,i did n obta9 any exp]im5tal evid5ce ) cond5s] dis*>ges4 ,a lum9\s b& excit$ 9 ! bulb by repeat$ dis*>ges ( a ,leyd5 j> mu/ possess rigidity1 & if de=m$ & sudd5ly releas$1 %\ld vibrate4 ,b probably ! am\nt ( vibrat+ matt] is s small t 9 spite ( ! extreme spe$1 ! in]tia _c prom95tly ass]t itself4 ,besides1 ! obs]vation 9 su* a case is r5d]$ extremely difficult on acc\nt ( ! fundam5tal vibration4 ,! demon/ration ( ! fact--:i* /ill ne$s bett] exp]im5tal confirmation--t a vibrat+ gase\s column possesses rigidity1 might greatly modify ! views ( ?9k]s4 ,:5 ) l[ frequ5cies & insignificant pot5tials indications ( t prop]ty may be not$1 h[ mu/ a gase\s m$ium behave "u ! influ5ce ( enorm\s electro/atic /resses :i* may be active 9 ! int]/ell> space1 & :i* may alt]nate ) inconceivable rapidity8 ,! exi/5ce ( su* an electro/atic1 rhy?mically ?robb+ =ce--( a vibrat+ electro/atic field--w\ld %[ a possible way h[ solids might h =m$ f ! ultra-gase\s ut]us1 & h[ transv]se & all k9ds ( vibrations may be transmitt$ ?r\gh a gase\s m$ium fill+ all space4 ,!n1 e!r might be a true fluid1 devoid ( rigidity1 & at re/1 x be+ m]ely necess>y z a connect+ l9k to enable int]action4 ,:at det]m9es ! rigidity ( a body8 ,x mu/ be ! spe$ & ! am\nt ( motive matt]4 ,9 a gas ! spe$ maybe consid]able1 b ! d5sity is exce$+ly small2 9 a liquid ! spe$ w\ld be likely to be small1 ?\gh ! d5sity may be consid]able2 & 9 bo? cases ! in]tia resi/ance (f]$ to displacem5t is practically nil4 ,b place a gase\s 7or liquid7 column 9 an int5se1 rapidly alt]nat+ electro/atic field1 set ! p>ticles vibrat+ ) enorm\s spe$s1 !n ! in]tia resi/ance ass]ts itself4 ,a body might move ) m or less fre$om ?r\gh ! vibrat+ mass1 b z a :ole x w\ld be rigid4 ,!re is a subject :i* ,i mu/ m5tion 9 connection ) ^! exp]im5ts3 x is t ( high vacua4 ,?is is a subject1 ! /udy ( :i* is n only int]e/+1 b useful1 = x may lead to results ( great practical importance4 ,9 comm]cial app>atus1 su* z inc&esc5t lamps1 op]at$ f ord9>y sy/ems ( di/ribution1 a mu* high] vacuum ?an is obta9$ at pres5t w\ld n secure a v great advantage4 ,9 su* a case ! "w is p]=m$ on ! filam5t1 & ! gas is little conc]n$2 ! improvem5t1 !re=e1 w\ld be b trifl+4 ,b :5 we beg9 to use v high frequ5cies & pot5tials1 ! action ( ! gas becomes all important1 & ! degree ( exhau/ion mat]ially modifies ! results4 ,z long z ord9>y coils1 ev5 v l>ge ones1 7 us$1 ! /udy ( ! subject 0 limit$1 because j at a po9t :5 x became mo/ int]e/+ x _h to be int]rupt$ on acc\nt ( ! non-/rik+ vacuum be+ rea*$4 ,b at pres5t we are able to obta9 f a small disruptive dis*>ge coil pot5tials mu* high] ?an ev5 ! l>ge/ coil 0 capable ( giv+1 &1 :at is m1 we c make ! pot5tial alt]nate ) great rapidity4 ,bo? ( ^! results enable u n[ to pass a lum9\s dis*>ge ?r\gh almo/ any vacua obta9able1 & ! field ( our inve/igations is greatly ext5d$4 ,?9k we z we may1 ( all ! possible directions to develop a practical illum9ant1 ! l9e ( high vacua seems to be ! mo/ promis+ at pres5t4 ,b to rea* extreme vacua ! appliances mu/ be mu* m improv$1 & ultimate p]fection w n be atta9$ until we %all h dis*>g$ ! me*anical & p]fect$ an electrical vacuum pump4 ,molecules & atoms c be ?r[n out ( a bulb "u ! action ( an enorm\s pot5tial3 ?is w be ! pr9ciple ( ! vacuum pump ( ! future4 ,= ! pres5t1 we mu/ secure ! be/ results we c ) me*anical appliances4 ,9 ?is respect1 x might n be out ( ! way to say a few words ab\t ! me?od (1 & app>atus =1 produc+ excessively high degrees ( exhau/ion ( :i* ,i h avail$ myself 9 ! c\rse ( ^! inve/igations4 ,x is v probable t o!r exp]im5t]s h us$ simil> arrangem5ts2 b z x is possible t !re may be an item ( int]e/ 9 _! description1 a few rem>ks1 :i* w r5d] ?is inve/igation m complete1 might be p]mitt$4 ,illu/ration3 ,,fig4 #aei4 ,! app>atus is illu/rat$ 9 a draw+ %[n 9 ,fig4 #aei4 ,s repres5ts a ,spr5gel pump1 :i* has be5 specially con/ruct$ to bett] suit ! "w requir$4 ,! /op-cock :i* is usually employ$ has be5 omitt$1 & in/ead ( x a holl[ /opp] s has be5 fitt$ 9 ! neck ( ! res]voir ,r4 ,?is /opp] has a small hole h1 ?r\gh :i* ! m]cury desc5ds2 ! size ( ! outlet o be+ prop]ly det]m9$ ) respect to ! section ( ! fall tube t1 :i* is seal$ to ! res]voir in/ead ( be+ connect$ to x 9 ! usual mann]4 ,?is arrangem5t ov]comes ! imp]fections & tr\bles :i* (t5 arise f ! use ( ! /opcock on ! res]voir & ! connections ( ! latt] ) ! fall tube4 ,! pump is connect$ ?r\gh a ,u-%ap$ tube t to a v l>ge res]voir ,r#a4 ,especial c>e 0 tak5 9 fitt+ ! gr9d+ surfaces ( ! /opp]s p & p#a1 & bo? ( ^! & ! m]cury caps above !m 7 made exceptionally long4 ,aft] ! ,u-%ap$ tube 0 fitt$ & put 9 place1 x 0 heat$1 s z to s(t5 & take (f ! /ra9 result+ f imp]fect fitt+4 ,! ,u-%ap$ tube 0 provid$ ) a /opcock ,c1 & two gr\nd connections g & g#a1--"o = a small bulb b1 usually conta9+ cau/ic pota%1 & ! o!r = ! receiv] r1 to be exhau/$4 ,! res]voir ,r#a1 0 connect$ by means ( a rubb] tube to a slightly l>g] res]voir ,r#b1 ea* ( ! two res]voirs be+ provid$ ) a /opcock ,c#a & ,c#b1 respectively4 ,! res]voir ,r#b c\ld be rais$ & l[]$ by a :eel & rack1 & ! range ( its motion 0 s det]m9$ t :5 x 0 fill$ ) m]cury & ! /opcock ,c#b clos$1 s z to =m a ,torricellian vacuum 9 x :5 rais$1 x c\ld be lift$ s high t ! res]voir ,r#a w\ld /& a little above /opcock ,c#a2 & :5 ?is /opcock 0 clos$ & ! res]voir ,r#b desc5d$1 s z to =m a ,torricellian vacuum 9 res]voir ,r#a1 x c\ld be l[]$ s f> z to completely empty ! latt]1 ! m]cury fill+ ! res]voir ,r#b up to a little above /opcock ,c#b4 ,! capacity ( ! pump & ( ! connections 0 tak5 z small z possible relatively to ! volume ( res]voir1 ,r#a1 s9ce1 ( c\rse1 ! degree ( exhau/ion dep5d$ ^u ! ratio ( ^! quantities4 ,) ?is app>atus ,i comb9$ ! usual means indicat$ by =m] exp]im5ts = ! production ( v high vacua4 ,9 mo/ ( ! exp]im5ts x 0 mo/ conv5i5t to use cau/ic pota%4 ,i may v5ture to say1 9 reg>d to its use1 t mu* "t is sav$ & a m p]fect action ( ! pump insur$ by fus+ & boil+ ! pota% z soon z1 or ev5 be=e1 ! pump settles d[n4 ,if ?is c\rse is n foll[$1 ! /icks1 z ord9>ily employ$1 may give (f moi/ure at a c]ta9 v sl[ rate1 & ! pump may "w = _m h\rs )\t rea*+ a v high vacuum4 ,! pota% 0 heat$ ei!r by a _s lamp or by pass+ a dis*>ge ?r\gh x1 or by pass+ a curr5t ?r\gh a wire conta9$ 9 x4 ,! advantage 9 ! latt] case 0 t ! heat+ c\ld be m rapidly repeat$4 ,g5]ally ! process ( exhau/ion 0 ! foll[+3--,at ! />t1 ! /op-cocks ,c & ,c#a be+ op51 & all o!r connections clos$1 ! res]voir ,r#b 0 rais$ s f> t ! m]cury fill$ ! res]voir ,r#a & a "p ( ! n>r[ connect+ ,u-%ap$ tube4 ,:5 ! pump 0 set to "w1 ! m]cury w\ld1 ( c\rse1 quickly rise 9 ! tube1 & res]voir ,r#b 0 l[]$1 ! exp]im5t] keep+ ! m]cury at ab\t ! same level4 ,! res]voir ,r#b 0 balanc$ by a long spr+ :i* facilitat$ ! op]ation1 & ! friction ( ! p>ts 0 g5]ally suffici5t to keep x 9 almo/ any position4 ,:5 ! ,spr5gel pump _h done its "w1 ! res]voir ,r#b 0 fur!r l[]$ & ! m]cury desc5d$ 9 ,r#a & fill$ ,r#b1 :]eupon /opcock ,c#b 0 clos$4 ,! air adh]+ to ! walls ( ,r#a & t absorb$ by ! m]cury 0 c>ri$ (f1 & to free ! m]cury ( all air ! res]voir ,r#b 0 = a long "t work$ up & d[n4 ,dur+ ?is process "s air1 :i* w\ld ga!r bel[ /opcock ,c#b1 0 expell$ f ,r#b by l[]+ x f> en\gh & op5+ ! /opcock1 clos+ ! latt] aga9 be=e rais+ ! res]voir4 ,:5 all ! air _h be5 expell$ f ! m]cury1 & no air w\ld ga!r 9 ,r#b :5 x 0 l[]$1 ! cau/ic pota% 0 resort$ to4 ,! res]voir ,r#b 0 n[ aga9 rais$ until ! m]cury 9 ,r#a1 /ood above /opcock ,c#a4 ,! cau/ic pota% 0 fus$ & boil$1 & moi/ure p>tly c>ri$ (f by ! pump & p>tly re-absorb$2 & ?is process ( heat+ & cool+ 0 repeat$ _m times1 & ea* "t1 ^u ! moi/ure be+ absorb$ or c>ri$ (f1 ! res]voir ,r#b 0 = a long "t rais$ & l[]$4 ,9 ?is mann] all ! moi/ure 0 c>ri$ (f f ! m]cury1 & bo? ! res]voirs 7 9 prop] condition to be us$4 ,! res]voir ,r#b 0 !n aga9 rais$ to ! top1 & ! pump 0 kept work+ = a long "t4 ,:5 ! highe/ vacuum obta9able ) ! pump _h be5 rea*$1 ! pota% bulb 0 usually wrapp$ ) cotton :i* 0 spr9kl$ ) e!r s z to keep ! pota% at a v l[ temp]ature1 !n ! res]voir ,r#b 0 l[]$1 & ^u res]voir ,r#a be+ empti$ ! receiv] 0 quickly seal$ up4 ,:5 a new bulb 0 put on1 ! m]cury 0 always rais$ above /opcock ,c#a1 :i* 0 clos$1 s z to always keep ! m]cury & bo? ! res]voirs 9 f9e condition1 & ! m]cury 0 nev] )drawn f ,r#a except :5 ! pump _h rea*$ ! highe/ degree ( exhau/ion4 ,x is necess>y to obs]ve ?is rule if x is desir$ to use ! app>atus to advantage4 ,by means ( ?is arrangem5t ,i 0 able to proce$ v quickly1 & :5 ! app>atus 0 9 p]fect ord] x 0 possible to rea* ! phosphoresc5t /age 9 a small bulb 9 less ?an fifte5 m9utes1 :i* is c]ta9ly v quick "w = a small laboratory arrangem5t requir+ all 9 all ab\t #ajj p\nds ( m]cury4 ,) ord9>y small bulbs ! ratio ( ! capacity ( ! pump1 receiv]1 & connections1 & t ( res]voir ,r 0 ab\t #a to #bj1 & ! degrees ( exhau/ion rea*$ 7 necess>ily v high1 ?\gh ,i am unable to make a precise & reliable /atem5t h[ f> ! exhau/ion 0 c>ri$4 ,:at impresses ! inve/igator mo/ 9 ! c\rse ( ^! exp]i5ces is ! behavior ( gases :5 subject$ to great rapidly alt]nat+ electro/atic /resses4 ,b he mu/ rema9 9 d\bt z to :e!r ! effects obs]v$ are due :olly to ! molecules1 or atoms1 ( ! gas :i* *emical analysis discloses to u1 or :e!r !re ent]s into play ano!r m$ium ( a gase\s nature1 compris+ atoms1 or molecules1 imm]s$ 9 a fluid p]vad+ ! space4 ,su* a m$ium surely mu/ exi/1 & ,i am conv9c$ t1 = in/ance1 ev5 if air 7 abs5t1 ! surface & neighborhood ( a body 9 space w\ld be heat$ by rapidly alt]nat+ ! pot5tial ( ! body2 b no su* heat+ ( ! surface or neighborhood c\ld occur if all free atoms 7 remov$ & only a homog5e\s1 incompressible1 & ela/ic fluid--su* z e!r is suppos$ to be--w\ld rema91 = !n !re w\ld be no impacts1 no collisions4 ,9 su* a case1 z f> z ! body itself is conc]n$1 only frictional losses 9 ! inside c\ld occur4 ,x is a /rik+ fact t ! dis*>ge ?r\gh a gas is e/abli%$ ) ev]-increas+ fre$om z ! frequ5cy ( ! impulses is augm5t$4 ,x behaves 9 ?is respect q contr>ily to a metallic conductor4 ,9 ! latt] ! imp$ance ent]s prom95tly into play z ! frequ5cy is increas$1 b ! gas acts mu* z a s]ies ( cond5s]s w\ld2 ! facility ) :i* ! dis*>ge passes ?r\gh1 seems to dep5d on ! rate ( *ange ( pot5tial4 ,if x acts s1 !n 9 a vacuum tube ev5 ( great l5g?1 & no matt] h[ /rong ! curr5t1 self-induction c\ld n ass]t itself to any appreciable degree4 ,we h1 !n1 z f> z we c n[ see1 9 ! gas a conductor :i* is capable ( transmitt+ electric impulses ( any frequ5cy :i* we may be able to produce4 ,c\ld ! frequ5cy be br\ght high en\gh1 !n a que] sy/em ( electric di/ribution1 :i* w\ld be likely to int]e/ gas companies1 might be realiz$3 metal pipes fill$ ) gas--! metal be+ ! insulator1 ! gas ! conductor--supply+ phosphoresc5t bulbs1 or p]haps devices z yet un9v5t$4 ,x is c]ta9ly possible to take a holl[ core ( copp]1 r>efy ! gas 9 ! same1 & by pass+ impulses ( suffici5tly high frequ5cy ?r\gh a circuit ar\nd x1 br+ ! gas inside to a high degree ( inc&esc5ce2 b z to ! nature ( ! =ces !re w\ld be consid]able unc]ta9ty1 = x w\ld be d\btful :e!r ) su* impulses ! copp] core w\ld act z a /atic scre54 ,su* p>adoxes & app>5t impossibilities we enc\nt] at e /ep 9 ?is l9e ( "w1 & !re9 lies1 to a great ext5t1 ! *>m ( ! /udy4 ,i h "h a %ort & wide tube :i* is exhau/$ to a high degree & cov]$ ) a sub/antial coat+ ( bronze1 ! coat+ b>ely all[+ ! light to %9e ?r\gh4 ,a metallic cap1 ) a hook = susp5d+ ! tube1 is fa/5$ ar\nd ! middle portion ( ! latt]1 ! clasp be+ 9 contact ) ! bronze coat+4 ,i n[ want to light ! gas inside by susp5d+ ! tube on a wire connect$ to ! coil4 ,any "o :o w\ld try ! exp]im5t = ! fir/ "t1 n hav+ any previ\s exp]i5ce1 w\ld probably take c>e to be q alone :5 mak+ ! trial1 = fe> t he might become ! joke ( 8 assi/ants4 ,/ill1 ! bulb lights 9 spite ( ! metal coat+1 & ! light c be di/9ctly p]ceiv$ ?r\gh ! latt]4 ,a long tube cov]$ ) alum9um bronze lights :5 held 9 "o h&--! o!r t\*+ ! t]m9al ( ! coil--q p[]fully4 ,x might be object$ t ! coat+s are n suffici5tly conduct+2 /ill1 ev5 if !y 7 highly resi/ant1 !y ought to scre5 ! gas4 ,!y c]ta9ly scre5 x p]fectly 9 a condition ( re/1 b f> f p]fectly :5 ! *>ge is surg+ 9 ! coat+4 ,b ! loss ( en]gy :i* occurs )9 ! tube1 not)/&+ ! scre51 is occasion$ pr9cipally by ! pres5ce ( ! gas4 ,7 we to take a l>ge holl[ metallic sph]e & fill x ) a p]fect1 incompressible1 fluid dielectric1 !re w\ld be no loss inside ( ! sph]e1 & consequ5tly ! inside might be consid]$ z p]fectly scre5$1 ?\gh ! pot5tial be v rapidly alt]nat+4 ,ev5 7 ! sph]e fill$ ) oil1 ! loss w\ld be incomp>ably small] ?an :5 ! fluid is replac$ by a gas1 = 9 ! latt] case ! =ce produces displacem5ts2 t means impact & collisions 9 ! inside4 ,no matt] :at ! pressure ( ! gas may be1 x becomes an important factor 9 ! heat+ ( a conductor :5 ! electric d5sity is great & ! frequ5cy v high4 ,t 9 ! heat+ ( conductors by lightn+ dis*>ges1 air is an elem5t ( great importance1 is almo/ z c]ta9 z an exp]im5tal fact4 ,i may illu/rate ! action ( ! air by ! foll[+ exp]im5t3 ,i take a %ort tube :i* is exhau/$ to a mod]ate degree & has a plat9um wire runn+ ?r\gh ! middle f "o end to ! o!r4 ,i pass a /eady or l[ frequ5cy curr5t ?r\gh ! wire1 & x is heat$ uni=mly 9 all p>ts4 ,! heat+ "h is due to conduction1 or frictional losses1 & ! gas ar\nd ! wire has--z f> z we c see--no function to p]=m4 ,b n[ let me pass sudd5 dis*>ges1 or high frequ5cy curr5ts1 ?r\gh ! wire4 ,aga9 ! wire is heat$1 ?is "t pr9cipally on ! ends & lea/ 9 ! middle portion2 & if ! frequ5cy ( ! impulses1 or ! rate ( *ange1 is high en\gh1 ! wire might z well be cut 9 ! middle z n1 = practically all heat+ is due to ! r>efi$ gas4 ,"h ! gas might only act z a conductor ( no imp$ance div]t+ ! curr5t f ! wire z ! imp$ance ( ! latt] is enorm\sly increas$1 & m]ely heat+ ! ends ( ! wire by reason ( _! resi/ance to ! passage ( ! dis*>ge4 ,b x is n at all necess>y t ! gas 9 ! tube %\ld be conduct+2 x might be at an extremely l[ pressure1 /ill ! ends ( ! wire w\ld be heat$--z1 h[ev]1 is asc]ta9$ by exp]i5ce--only ! two ends w\ld 9 su* case n be electrically connect$ ?r\gh ! gase\s m$ium4 ,n[ :at ) ^! frequ5cies & pot5tials occurs 9 an exhau/$ tube1 occurs 9 ! lightn+ dis*>ges at ord9>y pressure4 ,we only ne$ rememb] "o ( ! facts arriv$ at 9 ! c\rse ( ^! inve/igations1 namely1 t to impulses ( v high frequ5cy ! gas at ord9>y pressure behaves mu* 9 ! same mann] z ?\gh x 7 at mod]ately l[ pressure4 ,i ?9k t 9 lightn+ dis*>ges frequ5tly wires or conduct+ objects are volatiliz$ m]ely because air is pres5t1 & t1 7 ! conductor imm]s$ 9 an insulat+ liquid1 x w\ld be safe1 = !n ! en]gy w\ld h to sp5d itself some:]e else4 ,f ! behavior ( gases "u sudd5 impulses ( high pot5tial1 ,i am l$ to conclude t !re c be no sur] way ( div]t+ a lightn+ dis*>ge ?an by af=d+ x a passage ?r\gh a volume ( gas1 if su* a ?+ c be done 9 a practical mann]4 ,!re are two m features ^u :i* ,i ?9k x necess>y to dwell 9 connection ) ^! exp]im5ts--! radiant /ate & ! non-/rik+ vacuum4 ,any "o :o has /udi$ ,crookes' "w mu/ h receiv$ ! impression t ! radiant /ate is a prop]ty ( ! gas insep>ably connect$ ) an extremely high degree ( exhau/ion4 ,b x %\ld be rememb]$ t ! ph5om5a obs]v$ 9 an exhau/$ vessel are limit$ to ! "* & capacity ( ! app>atus :i* is made use (4 ,i ?9k t 9 a bulb a molecule1 or atom1 does n precisely move 9 a /raight l9e because x meets no ob/acle1 b because ! velocity imp>t$ to x is suffici5t to propel x 9 a s5sibly /raight l9e4 ,! mean free pa? is "o ?+1 b ! velocity--! en]gy associat$ ) ! mov+ body--is ano!r1 & "u ord9>y circum/ances ,i believe t x is a m]e "q ( pot5tial or spe$4 ,a disruptive dis*>ge coil1 :5 ! pot5tial is pu%$ v f>1 excites phosphoresc5ce & projects %ad[s1 at comp>atively l[ degrees ( exhau/ion4 ,9 a lightn+ dis*>ge1 matt] moves 9 /raight l9es at ord9>y pressure :5 ! mean free pa? is exce$+ly small1 & frequ5tly images ( wires or o!r metallic objects h be5 produc$ by ! p>ticles ?r[n (f 9 /raight l9es4 ,i h prep>$ a bulb to illu/rate by an exp]im5t ! correctness ( ^! ass]tions4 ,9 a globe ,l1 ,fig4 #afj1 ,i h m\nt$ ^u a lamp filam5t f a piece ( lime l4 ,! lamp filam5t is connect$ ) a wire :i* leads into ! bulb1 & ! g5]al con/ruction ( ! latt] is z indicat$ 9 ,fig4 #adh1 be=e describ$4 ,! bulb be+ susp5d$ f a wire connect$ to ! t]m9al ( ! coil1 & ! latt] be+ set to "w1 ! lime piece l & ! project+ p>ts ( ! filam5t f are bomb>d$4 ,! degree ( exhau/ion is j su* t ) ! pot5tial ! coil is capable ( giv+1 phosphoresc5ce ( ! glass is produc$1 b disappe>s z soon z ! vacuum is impair$4 ,! lime conta9+ moi/ure1 & moi/ure be+ giv5 (f z soon z heat+ occurs1 ! phosphoresc5ce la/s only = a few mom5ts4 ,:5 ! lime has be5 suffici5tly heat$1 en\gh moi/ure has be5 giv5 (f to impair mat]ially ! vacuum ( ! bulb4 ,z ! bomb>dm5t goes on1 "o po9t ( ! lime piece is m heat$ ?an o!r po9ts1 & ! result is t f9ally practically all ! dis*>ge passes ?r\gh t po9t :i* is int5sely heat$1 & a :ite /ream ( lime p>ticles 7,fig4 #afj7 !n breaks =? f t po9t4 ,?is /ream is compos$ ( radiant matt]1 yet ! degree ( exhau/ion is l[4 ,b ! p>ticles move 9 /raight l9es because ! velocity imp>t$ to !m is great1 & ?is is due to ?ree causes--to ! great electric d5sity1 ! high temp]ature ( ! small po9t1 & ! fact t ! p>ticles ( ! lime are easily torn & ?r[n (f--f> m easily ?an ^? ( c>bon4 ,) frequ5cies su* z we are able to obta91 ! p>ticles are bodily ?r[n (f & project$ to a consid]able di/ance2 b ) suffici5tly high frequ5cies no su* ?+ w\ld occur2 9 su* case only a /ress w\ld spread or a vibration w\ld be propagat$ ?r\gh ! bulb4 ,x w\ld be out ( ! "q to rea* any su* frequ5cy on ! assumption t ! atoms move ) ! spe$ ( light2 b ,i believe t su* a ?+ is impossible2 = ?is an enorm\s pot5tial w\ld be requir$4 ,) pot5tials :i* we are able to obta91 ev5 ) a disruptive dis*>ge coil1 ! spe$ mu/ be q insignificant4 ,illu/ration3 ,,fig4 #afj4 ,z to ! non-/rik+ vacuum1 ! po9t to be not$ is1 t x c occur only ) l[ frequ5cy impulses1 & x is necessitat$ by ! impossibility ( c>ry+ (f en\gh en]gy ) su* impulses 9 high vacuum1 s9ce ! few atoms :i* are ar\nd ! t]m9al ^u com+ 9 contact ) ! same1 are repell$ & kept at a di/ance = a comp>atively long p]iod ( "t1 & n en\gh "w c be p]=m$ to r5d] ! effect p]ceptible to ! eye4 ,if ! diff]5ce ( pot5tial betwe5 ! t]m9als is rais$1 ! dielectric breaks d[n4 ,b ) v high frequ5cy impulses !re is no necessity = su* break+ d[n1 s9ce any am\nt ( "w c be p]=m$ by cont9ually agitat+ ! atoms 9 ! exhau/$ vessel1 provid$ ! frequ5cy is high en\gh4 ,x is easy to rea*--ev5 ) frequ5cies obta9$ f an alt]nator z "h us$--a /age at :i* ! dis*>ge does n pass betwe5 two electrodes 9 a n>r[ tube1 ea* ( ^! be+ connect$ to "o ( ! t]m9als ( ! coil1 b x is difficult to rea* a po9t at :i* a lum9\s dis*>ge w\ld n occur ar\nd ea* electrode4 ,illu/ration3 ,,fig4 #afa4 ,illu/ration3 ,,fig4 #afb4 ,a ?\ght :i* naturally pres5ts itself 9 connection ) high frequ5cy curr5ts1 is to make use ( _! p[]ful electrodynamic inductive action to produce light effects 9 a seal$ glass globe4 ,! lead+-9 wire is "o ( ! defects ( ! pres5t inc&esc5t lamp1 & if no o!r improvem5t 7 made1 t imp]fection at lea/ %\ld be done away )4 ,foll[+ ?is ?\ght1 ,i h c>ri$ on exp]im5ts 9 v>i\s directions1 ( :i* "s 7 indicat$ 9 my =m] pap]4 ,i may "h m5tion "o or two m l9es ( exp]im5t :i* h be5 foll[$ up4 ,_m bulbs 7 con/ruct$ z %[n 9 ,fig4 #afa & ,fig4 #afb4 ,9 ,fig4 #afa1 a wide tube1 ,t1 0 seal$ to a small] ,w %ap$ tube ,u1 ( phosphoresc5t glass4 ,9 ! tube ,t1 0 plac$ a coil ,c1 ( alum9um wire1 ! ends ( :i* 7 provid$ ) small sph]es1 t & t#a1 ( alum9um1 & rea*$ into ! ,u tube4 ,! tube ,t 0 slipp$ into a socket conta9+ a prim>y coil1 ?r\gh :i* usually ! dis*>ges ( ,leyd5 j>s 7 direct$1 & ! r>efi$ gas 9 ! small ,u tube 0 excit$ to /rong lum9osity by ! high-t5sion curr5t induc$ 9 ! coil ,c4 ,:5 ,leyd5 j> dis*>ges 7 us$ to induce curr5ts 9 ! coil ,c1 x 0 f\nd necess>y to pack ! tube ,t tightly ) insulat+ p[d]1 z a dis*>ge w\ld occur frequ5tly betwe5 ! turns ( ! coil1 especially :5 ! prim>y 0 ?ick & ! air gap1 ?r\gh :i* ! j>s dis*>g$1 l>ge1 & no little tr\ble 0 exp]i5c$ 9 ?is way4 ,9 ,fig4 #afb is illu/rat$ ano!r =m ( ! bulb con/ruct$4 ,9 ?is case a tube ,t is seal$ to a globe ,l4 ,! tube conta9s a coil ,c1 ! ends ( :i* pass ?r\gh two small glass tubes t & t#a1 :i* are seal$ to ! tube ,t4 ,two refractory buttons m & m#a1 are m\nt$ on lamp filam5ts :i* are fa/5$ to ! ends ( ! wires pass+ ?r\gh ! glass tubes t & t#a4 ,g5]ally 9 bulbs made on ?is plan ! globe ,l communicat$ ) ! tube ,t4 ,= ?is purpose ! ends ( ! small tubes t & t#a 7 heat$ j a trifle 9 ! burn]1 m]ely to hold ! wires1 b n to int]f]e ) ! communication4 ,! tube ,t1 ) ! small tubes1 wires ?r\gh ! same1 & ! refractory buttons m & m#a1 7 fir/ prep>$1 & !n seal$ to globe ,l1 :]eupon ! coil ,c 0 slipp$ 9 & ! connections made to its ends4 ,! tube 0 !n pack$ ) insulat+ p[d]1 jamm+ ! latt] z tight z possible up to v ne>ly ! end2 !n x 0 clos$ & only a small hole left ?r\gh :i* ! rema9d] ( ! p[d] 0 introduc$1 & f9ally ! end ( ! tube 0 clos$4 ,usually 9 bulbs con/ruct$ z %[n 9 ,fig4 #afb an alum9um tube a 0 fa/5$ to ! upp] end s ( ea* ( ! tubes t & t#a 9 ord] to protect t end aga9/ ! heat4 ,! buttons m & m#a c\ld be br\ght to any degree ( inc&esc5ce by pass+ ! dis*>ges ( ,leyd5 j>s ar\nd ! coil ,c4 ,9 su* bulbs ) two buttons a v curi\s effect is produc$ by ! =mation ( ! %ad[s ( ea* ( ! two buttons4 ,ano!r l9e ( exp]im5t1 :i* has be5 assidu\sly foll[$1 0 to induce by electro-dynamic induction a curr5t or lum9\s dis*>ge 9 an exhau/$ tube or bulb4 ,?is matt] has receiv$ su* able treatm5t at ! h&s ( ,pr(4 ,j4 ,j4 ,?omson1 t ,i c\ld add b little to :at he has made kn[n1 ev5 _h ,i made x ! special subject ( ?is lecture4 ,/ill1 s9ce exp]im5ts 9 ?is l9e h gradually l$ me to ! pres5t views & results1 a few words mu/ be devot$ "h to ?is subject4 ,x has occurr$1 no d\bt1 to _m t z a vacuum tube is made long]1 ! electromotive =ce p] unit l5g? ( ! tube1 necess>y to pass a lum9\s dis*>ge ?r\gh ! latt]1 becomes cont9ually small]2 !re=e1 if ! exhau/$ tube be made long en\gh1 ev5 ) l[ frequ5cies a lum9\s dis*>ge c\ld be induc$ 9 su* a tube clos$ ^u itself4 ,su* a tube might be plac$ ar\nd a hall or on a ceil+1 & at once a simple appliance capable ( giv+ consid]able light w\ld be obta9$4 ,b ?is w\ld be an appliance h>d to manufacture & extremely unmanageable4 ,x w\ld n d to make ! tube up ( small l5g?s1 because !re w\ld be ) ord9>y frequ5cies consid]able loss 9 ! coat+s1 & besides1 if coat+s 7 us$1 x w\ld be bett] to supply ! curr5t directly to ! tube by connect+ ! coat+s to a trans=m]4 ,b ev5 if all objections ( su* nature 7 remov$1 ) l[ frequ5cies ! light conv]sion itself w\ld be ineffici5t1 z ,i h be=e /at$4 ,9 us+ extremely high frequ5cies ! l5g? ( ! second>y--9 o!r words1 ! size ( ! vessel--c be r$uc$ z mu* z desir$1 & ! effici5cy ( ! light conv]sion is increas$1 provid$ t means are inv5t$ = effici5tly obta9+ su* high frequ5cies4 ,?us "o is l$1 f !oretical & practical consid]ations1 to ! use ( high frequ5cies1 & ?is means high electromotive =ces & small curr5ts 9 ! prim>y4 ,:5 "o works ) cond5s] *>ges--& !y are ! only means up to ! pres5t kn[n = rea*+ ^! extreme frequ5cies--"o gets to electromotive =ces ( sev]al ?\s&s ( volts p] turn ( ! prim>y4 ,we _c multiply ! electro-dynamic inductive effect by tak+ m turns 9 ! prim>y1 = we arrive at ! conclusion t ! be/ way is to "w ) "o s+le turn--?\gh we mu/ sometimes dep>t f ?is rule--& we mu/ get along ) :atev] inductive effect we c obta9 ) "o turn4 ,b be=e "o has long exp]im5t$ ) ! extreme frequ5cies requir$ to set up 9 a small bulb an electromotive =ce ( sev]al ?\s&s ( volts1 "o realizes ! great importance ( electro/atic effects1 & ^! effects gr[ relatively to ! electro-dynamic 9 significance z ! frequ5cy is increas$4 ,n[1 if any?+ is desirable 9 ?is case1 x is to increase ! frequ5cy1 & ?is w\ld make x /ill worse = ! electrodynamic effects4 ,on ! o!r h&1 x is easy to exalt ! electro/atic action z f> z "o likes by tak+ m turns on ! second>y1 or comb9+ self-induction & capacity to raise ! pot5tial4 ,x %\ld also be rememb]$ t1 9 r$uc+ ! curr5t to ! smalle/ value & increas+ ! pot5tial1 ! electric impulses ( high frequ5cy c be m easily transmitt$ ?r\gh a conductor4 ,^! & simil> ?\ghts det]m9$ me to devote m att5tion to ! electro/atic ph5om5a1 & to endeavor to produce pot5tials z high z possible1 & alt]nat+ z fa/ z !y c\ld be made to alt]nate4 ,i !n f\nd t ,i c\ld excite vacuum tubes at consid]able di/ance f a conductor connect$ to a prop]ly con/ruct$ coil1 & t ,i c\ld1 by conv]t+ ! oscillatory curr5t ( a conductor to a high] pot5tial1 e/abli% electro/atic alt]nat+ fields :i* act$ ?r\gh ! :ole ext5t ( ! room1 light+ up a tube no matt] :]e x 0 held 9 space4 ,i ?\ght ,i recogniz$ t ,i _h made a /ep 9 advance1 & ,i h p]sev]$ 9 ?is l9e2 b ,i wi% to say t ,i %>e ) all lov]s ( sci5ce & progress ! "o & only desire--to rea* a result ( utility to m5 9 any direction to :i* ?\ght or exp]im5t may lead me4 ,i ?9k t ?is dep>ture is ! "r "o1 = ,i _c see1 f ! obs]vation ( ! ph5om5a :i* manife/ !mselves z ! frequ5cy is increas$1 :at !re w\ld rema9 to act betwe5 two circuits convey+1 = in/ance1 impulses ( sev]al hundr$ millions p] second1 except electro/atic =ces4 ,ev5 ) su* trifl+ frequ5cies ! en]gy w\ld be practically all pot5tial1 & my conviction has gr[n /rong t1 to :atev] k9d ( motion light may be due1 x is produc$ by trem5d\s electro/atic /resses vibrat+ ) extreme rapidity4 ,illu/ration3 ,,fig4 #afc4 ,illu/ration3 ,,fig4 #afd4 ,( all ^! ph5om5a obs]v$ ) curr5ts1 or electric impulses1 ( high frequ5cy1 ! mo/ fasc9at+ = an audi5ce are c]ta9ly ^? :i* are not$ 9 an electro/atic field act+ ?r\gh consid]able di/ance2 & ! be/ an unskill$ lectur] c d is to beg9 & f9i% ) ! exhibition ( ^! s+ul> effects4 ,i take a tube 9 my h& & move x ab\t1 & x is light$ :]ev] ,i may hold x2 ?r\gh\t space ! invisible =ces act4 ,b ,i may take ano!r tube & x might n light1 ! vacuum be+ v high4 ,i excite x by means ( a disruptive dis*>ge coil1 & n[ x w light 9 ! electro/atic field4 ,i may put x away = a few weeks or mon?s1 /ill x reta9s ! faculty ( be+ excit$4 ,:at *ange h ,i produc$ 9 ! tube 9 ! act ( excit+ x8 ,if a motion imp>t$ to atoms1 x is difficult to p]ceive h[ x c p]si/ s long )\t be+ arre/$ by frictional losses2 & if a /ra9 ex]t$ 9 ! dielectric1 su* z a simple electrification w\ld produce1 x is easy to see h[ x may p]si/ indef9itely1 b v difficult to und]/& :y su* a condition %\ld aid ! excitation :5 we h to deal ) pot5tials :i* are rapidly alt]nat+4 ,s9ce ,i h exhibit$ ^! ph5om5a = ! fir/ "t1 ,i h obta9$ "s o!r int]e/+ effects4 ,= in/ance1 ,i h produc$ ! inc&esc5ce ( a button1 filam5t1 or wire enclos$ 9 a tube4 ,to get to ?is result x 0 necess>y to economize ! en]gy :i* is obta9$ f ! field1 & direct mo/ ( x on ! small body to be r5d]$ inc&esc5t4 ,at ! beg9n+ ! task appe>$ difficult1 b ! exp]i5ces ga!r$ p]mitt$ me to rea* ! result easily4 ,9 ,fig4 #afc & ,fig4 #afd1 two su* tubes are illu/rat$1 :i* are prep>$ = ! occasion4 ,9 ,fig4 #afc a %ort tube ,t#a1 seal$ to ano!r long tube ,t1 is provid$ ) a /em s1 ) a plat9um wire seal$ 9 ! latt]4 ,a v ?9 lamp filam5t l1 is fa/5$ to ?is wire & connection to ! outside is made ?r\gh a ?9 copp] wire w4 ,! tube is provid$ ) outside & inside coat+s1 ,c & ,c#a1 respectively1 & is fill$ z f> z ! coat+s rea* ) conduct+1 & ! space above ) insulat+1 p[d]4 ,^! coat+s are m]ely us$ to enable me to p]=m two exp]im5ts ) ! tube--namely1 to produce ! effect desir$ ei!r by direct connection ( ! body ( ! exp]im5t] or ( ano!r body to ! wire w1 or by act+ inductively ?r\gh ! glass4 ,! /em s is provid$ ) an alum9um tube a1 = purposes be=e expla9$1 & only a small "p ( ! filam5t rea*es out ( ?is tube4 ,by hold+ ! tube ,t#a any:]e 9 ! electro/atic field1 ! filam5t is r5d]$ inc&esc5t4 ,a m int]e/+ piece ( app>atus is illu/rat$ 9 ,fig4 #afd4 ,! con/ruction is ! same z be=e1 only in/ead ( ! lamp filam5t a small plat9um wire p1 seal$ 9 a /em s1 & b5t above x 9 a circle1 is connect$ to ! copp] wire w1 :i* is jo9$ to an inside coat+ ,c4 ,a small /em s#a is provid$ ) a ne$le1 on ! po9t ( :i* is arrang$1 to rotate v freely1 a v light fan ( mica v4 ,to prev5t ! fan f fall+ out1 a ?9 /em ( glass g1 is b5t prop]ly & fa/5$ to ! alum9um tube4 ,:5 ! glass tube is held any:]e 9 ! electro/atic field ! plat9um wire becomes inc&esc5t1 & ! mica vanes are rotat$ v fa/4 ,int5se phosphoresc5ce may be excit$ 9 a bulb by m]ely connect+ x to a plate )9 ! field1 & ! plate ne$ n be any l>g] ?an an ord9>y lamp %ade4 ,! phosphoresc5ce excit$ ) ^! curr5ts is incomp>ably m p[]ful ?an ) ord9>y app>atus4 ,a small phosphoresc5t bulb1 :5 atta*$ to a wire connect$ to a coil1 emits suffici5t light to all[ read+ ord9>y pr9t at a di/ance ( five to six paces4 ,x 0 ( int]e/ to see h[ "s ( ! phosphoresc5t bulbs ( ,pr(essor ,crookes w\ld behave ) ^! curr5ts1 & he has _h ! k9dness to l5d me a few = ! occasion4 ,! effects produc$ are magnific5t1 especially by ! sulphide ( calcium & sulphide ( z9c4 ,) ! disruptive dis*>ge coil !y gl[ int5sely m]ely by hold+ !m 9 ! h& & connect+ ! body to ! t]m9al ( ! coil4 ,to :atev] results inve/igations ( ?is k9d may lead1 ! *ief int]e/ lies1 = ! pres5t1 9 ! possibilities !y (f] = ! production ( an effici5t illum9at+ device4 ,9 no bran* ( electric indu/ry is an advance m desir$ ?an 9 ! manufacture ( light4 ,e ?9k]1 :5 consid]+ ! b>b>\s me?ods employ$1 ! deplorable losses incurr$ 9 our be/ sy/ems ( light production1 mu/ h ask$ himself1 ,:at is likely to be ! light ( ! future8 ,is x to be an inc&esc5t solid1 z 9 ! pres5t lamp1 or an inc&esc5t gas1 or a phosphoresc5t body1 or some?+ l a burn]1 b incomp>ably m effici5t8 ,!re is little *ance to p]fect a gas burn]2 n1 p]haps1 because human +5uity has be5 b5t ^u t problem = c5turies )\t a radical dep>ture hav+ be5 made--?\gh ! argum5t is n devoid ( =ce--b because 9 a burn] ! highe/ vibrations c nev] be rea*$1 except by pass+ ?r\gh all ! l[ ones4 ,= h[ is a flame to proce$ unless by a fall ( lift$ weights8 ,su* process _c be ma9ta9$ )\t r5ewal1 & r5ewal is repeat$ pass+ f l[ to high vibrations4 ,"o way only seems to be op5 to improve a burn]1 & t is by try+ to rea* high] degrees ( inc&esc5ce4 ,high] inc&esc5ce is equival5t to a quick] vibration3 t means m light f ! same mat]ial1 & t aga91 means m economy4 ,9 ?is direction "s improvem5ts h be5 made1 b ! progress is hamp]$ by _m limitations4 ,disc>d+1 !n1 ! burn]1 !re rema9s ! ?ree ways fir/ m5tion$1 :i* are ess5tially electrical4 ,suppose ! light ( ! imm$iate future to be a solid1 r5d]$ inc&esc5t by electricity4 ,w\ld x n seem t x is bett] to employ a small button ?an a frail filam5t8 ,f _m consid]ations x c]ta9ly mu/ be conclud$ t a button is capable ( a high] economy1 assum+1 ( c\rse1 ! difficulties connect$ ) ! op]ation ( su* a lamp to be effectively ov]come4 ,b to light su* a lamp we require a high pot5tial2 & to get ?is economically1 we mu/ use high frequ5cies4 ,su* consid]ations apply ev5 m to ! production ( light by ! inc&esc5ce ( a gas1 or by phosphoresc5ce4 ,9 all cases we require high frequ5cies & high pot5tials4 ,^! ?\ghts occurr$ to me a long "t ago4 ,incid5tally we ga91 by ! use ( high frequ5cies1 _m advantages1 su* z high] economy 9 ! light production1 ! possibility ( work+ ) "o lead1 ! possibility ( do+ away ) ! lead+-9 wire1 etc4 ,! "q is1 h[ f> c we g ) frequ5cies8 ,ord9>y conductors rapidly lose ! facility ( transmitt+ electric impulses :5 ! frequ5cy is greatly increas$4 ,assume ! means = ! production ( impulses ( v great frequ5cy br\ght to ! utmo/ p]fection1 e "o w naturally ask h[ to transmit !m :5 ! necessity arises4 ,9 transmitt+ su* impulses ?r\gh conductors we mu/ rememb] t we h to deal ) pressure & fl[1 9 ! ord9>y int]pretation ( ^! t]ms4 ,let ! pressure increase to an enorm\s value1 & let ! fl[ correspond+ly dim9i%1 !n su* impulses--v>iations m]ely ( pressure1 z x 7--c no d\bt be transmitt$ ?r\gh a wire ev5 if _! frequ5cy be _m hundr$s ( millions p] second4 ,x w\ld1 ( c\rse1 be out ( "q to transmit su* impulses ?r\gh a wire imm]s$ 9 a gase\s m$ium1 ev5 if ! wire 7 provid$ ) a ?ick & excell5t insulation1 = mo/ ( ! en]gy w\ld be lo/ 9 molecul> bomb>dm5t & consequ5t heat+4 ,! end ( ! wire connect$ to ! s\rce w\ld be heat$1 & ! remote end w\ld receive b a trifl+ "p ( ! en]gy suppli$4 ,! prime necessity1 !n1 if su* electric impulses are to be us$1 is to f9d means to r$uce z mu* z possible ! dissipation4 ,! fir/ ?\ght is1 to employ ! ?9ne/ possible wire surr\nd$ by ! ?icke/ practicable insulation4 ,! next ?\ght is to employ electro/atic scre5s4 ,! insulation ( ! wire may be cov]$ ) a ?9 conduct+ coat+ & ! latt] connect$ to ! gr\nd4 ,b ?is w\ld n d1 z !n all ! en]gy w\ld pass ?r\gh ! conduct+ coat+ to ! gr\nd & no?+ w\ld get to ! end ( ! wire4 ,if a gr\nd connection is made x c only be made ?r\gh a conductor (f]+ an enorm\s imp$ance1 or ?r\gh a cond5s] ( extremely small capacity4 ,?is1 h[ev]1 does n d away ) o!r difficulties4 ,if ! wave l5g? ( ! impulses is mu* small] ?an ! l5g? ( ! wire1 !n correspond+ %ort waves w be set up 9 ! conduct+ coat+1 & x w be m or less ! same z ?\gh ! coat+ 7 directly connect$ to e>?4 ,x is !re=e necess>y to cut up ! coat+ 9 sections mu* %ort] ?an ! wave l5g?4 ,su* an arrangem5t does n /ill af=d a p]fect scre51 b x is t5 ?\s& times bett] ?an none4 ,i ?9k x pref]able to cut up ! conduct+ coat+ 9 small sections1 ev5 if ! curr5t waves be mu* long] ?an ! coat+4 ,if a wire 7 provid$ ) a p]fect electro/atic scre51 x w\ld be ! same z ?\gh all objects 7 remov$ f x at inf9ite di/ance4 ,! capacity w\ld !n be r$uc$ to ! capacity ( ! wire itself1 :i* w\ld be v small4 ,x w\ld !n be possible to s5d ov] ! wire curr5t vibrations ( v high frequ5cies at enorm\s di/ances1 )\t affect+ greatly ! "* ( ! vibrations4 ,a p]fect scre5 is ( c\rse out ( ! "q1 b ,i believe t ) a scre5 su* z ,i h j describ$ telephony c\ld be r5d]$ practicable across ! ,atlantic4 ,accord+ to my ideas1 ! gutta-p]*a cov]$ wire %\ld be provid$ ) a ?ird conduct+ coat+ subdivid$ 9 sections4 ,on ! top ( ?is %\ld be aga9 plac$ a lay] ( gutta-p]*a & o!r insulation1 & on ! top ( ! :ole ! armor4 ,b su* cables w n be con/ruct$1 = ere long intellig5ce--transmitt$ )\t wires--w ?rob ?r\gh ! e>? l a pulse ?r\gh a liv+ organism4 ,! wond] is t1 ) ! pres5t /ate ( k & ! exp]i5ces ga9$1 no attempt is be+ made to di/urb ! electro/atic or magnetic condition ( ! e>?1 & transmit1 if no?+ else1 intellig5ce4 ,x has be5 my *ief aim 9 pres5t+ ^! results to po9t out ph5om5a or features ( novelty1 & to advance ideas :i* ,i am hopeful w s]ve z />t+ po9ts ( new dep>tures4 ,x has be5 my *ief desire ?is ev5+ to ent]ta9 y ) "s novel exp]im5ts4 ,y\r applause1 s frequ5tly & g5]\sly accord$1 has told me t ,i h succe$$4 ,9 conclusion1 let me ?ank y mo/ he>tily = y\r k9dness & att5tion1 & assure y t ! honor ,i h _h 9 address+ su* a di/+ui%$ audi5ce1 ! pleasure ,i h _h 9 pres5t+ ^! results to a ga!r+ ( s _m able m5--& among !m also "s ( ^? 9 ^: "w = _m ye>s pa/ ,i h f\nd enlight5m5t & con/ant pleasure--,i %all nev] =get4 ,,*apt] ,,xxviii4 ,,on ,,light ,,& ,,o!r ,,high ,,frequ5cy ,,ph5om5a4#c #c ,a lecture deliv]$ be=e ! ,frankl9 ,in/itute1 ,philadelphia1 ,febru>y1 #ahic1 & be=e ! ,national ,electric ,light ,association1 ,/4 ,l\is1 ,m>*1 #ahic4 ,,introductory4--,,"s ,,?\ghts ,,on ,,! ,,eye4 ,:5 we look at ! _w ar\nd u1 on ,nature1 we are impress$ ) its beauty & gr&eur4 ,ea* ?+ we p]ceive1 ?\gh x may be vani%+ly small1 is 9 itself a _w1 t is1 l ! :ole ( ! univ]se1 matt] & =ce gov]n$ by law1--a _w1 ! contemplation ( :i* fills u ) feel+s ( wond] & irresi/ibly urges u to ceaseless ?\ght & inquiry4 ,b 9 all ?is va/ _w1 ( all objects our s5ses reveal to u1 ! mo/ m>vell\s1 ! mo/ appeal+ to our imag9ation1 appe>s no d\bt a highly develop$ organism1 a ?9k+ be+4 ,if !re is any?+ fitt$ to make u admire ,nature's h&iwork1 x is c]ta9ly ?is inconceivable /ructure1 :i* p]=ms its innum]able motions ( ob$i5ce to ext]nal influ5ce4 ,to und]/& its work+s1 to get a deep] insight into ?is ,nature's ma/]piece1 has ev] be5 = ?9k]s a fasc9at+ aim1 & aft] _m c5turies ( ardu\s rese>* m5 h arriv$ at a fair und]/&+ ( ! functions ( its organs & s5ses4 ,aga91 9 all ! p]fect h>mony ( its p>ts1 ( ! p>ts :i* con/itute ! mat]ial or tangible ( our be+1 ( all its organs & s5ses1 ! eye is ! mo/ wond]ful4 ,x is ! mo/ preci\s1 ! mo/ indisp5sable ( our p]ceptive or directive organs1 x is ! great gateway ?r\gh :i* all k ent]s ! m9d4 ,( all our organs1 x is ! "o1 :i* is 9 ! mo/ intimate relation ) t :i* we call intellect4 ,s intimate is ?is relation1 t x is (t5 said1 ! v s\l %[s itself 9 ! eye4 ,x c be tak5 z a fact1 :i* ! !ory ( ! action ( ! eye implies1 t = ea* ext]nal impression1 t is1 = ea* image produc$ ^u ! ret9a1 ! ends ( ! visual n]ves1 conc]n$ 9 ! conveyance ( ! impression to ! m9d1 mu/ be "u a peculi> /ress or 9 a vibratory /ate4 ,x n[ does n seem improbable t1 :5 by ! p[] ( ?\ght an image is evok$1 a di/9ct reflex action1 no matt] h[ weak1 is ex]t$ ^u c]ta9 ends ( ! visual n]ves1 & !re=e ^u ! ret9a4 ,w x ev] be )9 human p[] to analyze ! condition ( ! ret9a :5 di/urb$ by ?\ght or reflex action1 by ! help ( "s optical or o!r means ( su* s5sitiv5ess1 t a cle> idea ( its /ate might be ga9$ at any "t8 ,if ?is 7 possible1 !n ! problem ( read+ "o's ?\ghts ) precision1 l ! *>act]s ( an op5 book1 might be mu* easi] to solve ?an _m problems belong+ to ! doma9 ( positive physical sci5ce1 9 ! solution ( :i* _m1 if n ! majority1 ( sci5tific m5 implicitly believe4 ,helmholtz1 has %[n t ! fundi ( ! eye are !mselves1 lum9\s1 & he 0 able to see1 9 total d>kness1 ! movem5t ( 8 arm by ! light ( 8 own eyes4 ,?is is "o ( ! mo/ rem>kable exp]im5ts record$ 9 ! hi/ory ( sci5ce1 & probably only a few m5 c\ld satisfactorily repeat x1 = x is v likely1 t ! lum9osity ( ! eyes is associat$ ) uncommon activity ( ! bra9 & great imag9ative p[]4 ,x is fluoresc5ce ( bra9 action1 z x 74 ,ano!r fact hav+ a be>+ on ?is subject :i* has probably be5 not$ by _m1 s9ce x is /at$ 9 popul> expressions1 b :i* ,i _c recollect to h f\nd *ronicl$ z a positive result ( obs]vation is1 t at times1 :5 a sudd5 idea or image pres5ts itself to ! intellect1 !re is a di/9ct & sometimes pa9ful s5sation ( lum9osity produc$ 9 ! eye1 obs]vable ev5 9 broad daylight4 ,! say+ !n1 t ! s\l %[s itself 9 ! eye1 is deeply f\nd$1 & we feel t x expresses a great tru?4 ,x has a pr(\nd mean+ ev5 = "o :o1 l a poet or arti/1 only foll[+ 8 inborn in/9ct or love = ,nature1 f9ds delight 9 aimless ?\ghts & 9 ! m]e contemplation ( natural ph5om5a1 b a /ill m pr(\nd mean+ = "o :o1 9 ! _s ( positive sci5tific inve/igation1 seeks to asc]ta9 ! causes ( ! effects4 ,x is pr9cipally ! natural philosoph]1 ! physici/1 = :om ! eye is ! subject ( ! mo/ int5se admiration4 ,two facts ab\t ! eye mu/ =cibly impress ! m9d ( ! physici/1 not)/&+ he may ?9k or say t x is an imp]fect optical in/rum5t1 =gett+1 t ! v conception ( t :i* is p]fect or seems s to him1 has be5 ga9$ ?r\gh ?is same in/rum5t4 ,fir/1 ! eye is1 z f> z our positive k goes1 ! only organ :i* is directly affect$ by t subtile m$ium1 :i* z sci5ce tea*es u1 mu/ fill all space2 secondly1 x is ! mo/ s5sitive ( our organs1 incomp>ably m s5sitive to ext]nal impressions ?an any o!r4 ,! organ ( he>+ implies ! impact ( pond]able bodies1 ! organ ( smell ! transf]5ce ( deta*$ mat]ial p>ticles1 & ! organs ( ta/e1 & ( t\* or =ce1 ! direct contact1 or at lea/ "s int]f]5ce ( pond]able matt]1 & ?is is true ev5 9 ^? in/ances ( animal organisms1 9 :i* "s ( ^! organs are develop$ to a degree ( truly m>vel\s p]fection4 ,?is be+ s1 x seems wond]ful t ! organ ( sight solely %\ld be capable ( be+ /irr$ by t1 :i* all our o!r organs are p[]less to detect1 yet :i* plays an ess5tial "p 9 all natural ph5om5a1 :i* transmits all en]gy & su/a9s all motion &1 t mo/ intricate ( all1 life1 b :i* has prop]ties su* t ev5 a sci5tifically tra9$ m9d _c help draw+ a di/9ction betwe5 x & all t is call$ matt]4 ,consid]+ m]ely ?is1 & ! fact t ! eye1 by its m>vel\s p[]1 wid5s our o!rwise v n>r[ range ( p]ception f> beyond ! limits ( ! small _w :i* is our own1 to embrace myriads ( o!r worlds1 suns & />s 9 ! inf9ite dep?s ( ! univ]se1 w\ld make x ju/ifiable to ass]t1 t x is an organ ( a high] ord]4 ,its p]=mances are beyond compreh5sion4 ,nature z f> z we "k nev] produc$ any?+ m wond]ful4 ,we c get b>ely a fa9t idea ( its prodigi\s p[] by analyz+ :at x does & by comp>+4 ,:5 e!r waves imp+e ^u ! human body1 !y produce ! s5sations ( w>m? or cold1 pleasure or pa91 or p]haps o!r s5sations ( :i* we are n aw>e1 & any degree or int5sity ( ^! s5sations1 :i* degrees are inf9ite 9 numb]1 h5ce an inf9ite numb] ( di/9ct s5sations4 ,b our s5se ( t\*1 or our s5se ( =ce1 _c reveal to u ^! diff]5ces 9 degree or int5sity1 unless !y are v great4 ,n[ we c readily conceive h[ an organism1 su* z ! human1 9 ! et]nal process ( evolution1 or m philosophically speak+1 adaptation to ,nature1 be+ con/ra9$ to ! use ( only ! s5se ( t\* or =ce1 = in/ance1 might develop ?is s5se to su* a degree ( s5sitiv5ess or p]fection1 t x w\ld be capable ( di/+ui%+ ! m9ute/ diff]5ces 9 ! temp]ature ( a body ev5 at "s di/ance1 to a hundr$?1 or ?\s&?1 or million? "p ( a degree4 ,yet1 ev5 ?is app>5tly impossible p]=mance w\ld n beg9 to comp>e ) t ( ! eye1 :i* is capable ( di/+ui%+ & convey+ to ! m9d 9 a s+le in/ant innum]able peculi>ities ( ! body1 be x 9 =m1 or color1 or o!r respects4 ,?is p[] ( ! eye re/s ^u two ?+s1 namely1 ! rectil9e> propagation ( ! di/urbance by :i* x is effect$1 & ^u its s5sitiv5ess4 ,to say t ! eye is s5sitive is n say+ any?+4 ,comp>$ ) x1 all o!r organs are mon/r\sly crude4 ,! organ ( smell :i* guides a dog on ! trail ( a de]1 ! organ ( t\* or =ce :i* guides an insect 9 its w&]+s1 ! organ ( he>+1 :i* is affect$ by ! slighte/ di/urbances ( ! air1 are s5sitive organs1 to be sure1 b :at are !y comp>$ ) ! human eye6 ,no d\bt x responds to ! fa9te/ e*oes or rev]b]ations ( ! m$ium2 no d\bt1 x br+s u tid+s f o!r worlds1 inf9itely remote1 b 9 a language we _c z yet always und]/&4 ,& :y n8 ,because we live 9 a m$ium fill$ ) air & o!r gases1 vapors & a d5se mass ( solid p>ticles fly+ ab\t4 ,^! play an important "p 9 _m ph5om5a2 !y fritt] away ! en]gy ( ! vibrations be=e !y c rea* ! eye2 !y too1 are ! c>ri]s ( g]ms ( de/ruction1 !y get into our lungs & o!r organs1 clog up ! *annels & imp]ceptibly1 yet inevitably1 arre/ ! /ream ( life4 ,c\ld we b d away ) all pond]able matt] 9 ! l9e ( sight ( ! telescope1 x w\ld reveal to u undreamt ( m>vels4 ,ev5 ! unaid$ eye1 ,i ?9k1 w\ld be capable ( di/+ui%+ 9 ! pure m$ium1 small objects at di/ances measur$ probably by hundr$s or p]haps ?\s&s ( miles4 ,b !re is some?+ else ab\t ! eye :i* impresses u /ill m ?an ^! wond]ful features :i* we obs]v$1 view+ x f ! /&po9t ( a physici/1 m]ely z an optical in/rum5t1--some?+ :i* appeals to u m ?an its m>vel\s faculty ( be+ directly affect$ by ! vibrations ( ! m$ium1 )\t int]f]5ce ( gross matt]1 & m ?an its inconceivable s5sitiv5ess & disc]n+ p[]4 ,x is its significance 9 ! processes ( life4 ,no matt] :at "o's views on nature & life may be1 he mu/ /& amaz$ :51 = ! fir/ "t 9 8 ?\ghts1 he realizes ! importance ( ! eye 9 ! physical processes & m5tal p]=mances ( ! human organism4 ,& h[ c\ld x be o!rwise1 :5 he realizes1 t ! eye is ! means ?r\gh :i* ! human race has acquir$ ! entire k x possesses1 t x controls all our motions1 m /ill1 all our actions4 ,!re is no way ( acquir+ k except ?r\gh ! eye4 ,:at is ! f\ndation ( all philosophical sy/ems ( anci5t & mod]n times1 9 fact1 ( all ! philosophy ( man8 ,i am1 ,i ?9k2 ,i ?9k1 !re=e ,i am4 ,b h[ c\ld ,i ?9k & h[ w\ld ,i "k t ,i exi/1 if ,i _h n ! eye8 ,= k involves consci\sness2 consci\sness involves ideas1 conceptions2 conceptions involve pictures or images1 & images ! s5se ( vision1 & !re=e ! organ ( sight4 ,b h[ ab\t bl9d m51 w be ask$8 ,yes1 a bl9d man may depict 9 magnific5t poems1 =ms & sc5es f real life1 f a _w he physically does n see4 ,a bl9d man may t\* ! keys ( an in/rum5t ) un]r+ precision1 may model ! fa/e/ boat1 may discov] & inv5t1 calculate & con/ruct1 may d /ill great] wond]s--b all ! bl9d m5 :o h done su* ?+s h desc5d$ f ^? :o _h see+ eyes4 ,nature may rea* ! same result 9 _m ways4 ,l a wave 9 ! physical _w1 9 ! inf9ite ocean ( ! m$ium :i* p]vades all1 s 9 ! _w ( organisms1 9 life1 an impulse />t$ proce$s onw>d1 at times1 may be1 ) ! spe$ ( light1 at times1 aga91 s sl[ly t = ages & ages x seems to /ay1 pass+ ?r\gh processes ( a complexity inconceivable to m51 b 9 all its =ms1 9 all its /ages1 its en]gy ev] & ev] integrally pres5t4 ,a s+le ray ( light f a di/ant /> fall+ ^u ! eye ( a tyrant 9 bygone times1 may h alt]$ ! c\rse ( 8 life1 may h *ang$ ! de/9y ( nations1 may h trans=m$ ! surface ( ! globe1 s intricate1 s inconceivably complex are ! processes 9 ,nature4 ,9 no way c we get su* an ov]:elm+ idea ( ! gr&eur ( ,nature1 z :5 we consid]1 t 9 accordance ) ! law ( ! cons]vation ( en]gy1 ?r\gh\t ! inf9ite1 ! =ces are 9 a p]fect balance1 & h5ce ! en]gy ( a s+le ?\ght may det]m9e ! motion ( a ,univ]se4 ,x is n necess>y t e individual1 n ev5 t e g5]ation or _m g5]ations1 %\ld h ! physical in/rum5t ( sight1 9 ord] to be able to =m images & to ?9k1 t is1 =m ideas or conceptions2 b sometime or o!r1 dur+ ! process ( evolution1 ! eye c]ta9ly mu/ h exi/$1 else ?\ght1 z we und]/& x1 w\ld be impossible2 else conceptions1 l _s1 intellect1 m9d1 call x z y may1 c\ld n exi/4 ,x is conceivable1 t 9 "s o!r _w1 9 "s o!r be+s1 ! eye is replac$ by a diff]5t organ1 equally or m p]fect1 b ^! be+s _c be m54 ,n[ :at prompts u all to volunt>y motions & actions ( any k9d8 ,aga9 ! eye4 ,if ,i am consci\s ( ! motion1 ,i mu/ h an idea or conception1 t is1 an image1 !re=e ! eye4 ,if ,i am n precisely consci\s ( ! motion1 x is1 because ! images are vague or indi/9ct1 be+ blurr$ by ! sup]imposition ( _m4 ,b :5 ,i p]=m ! motion1 does ! impulse :i* prompts me to ! action come f )9 or f )\t8 ,! greate/ physici/s h n disda9$ to endeavor to answ] ?is & simil> que/ions & h at times ab&on$ !mselves to ! delights ( pure & unre/ra9$ ?\ght4 ,su* que/ions are g5]ally consid]$ n to belong to ! realm ( positive physical sci5ce1 b w be=e long be annex$ to its doma94 ,helmholtz has probably ?\ght m on life ?an any mod]n sci5ti/4 ,"l ,kelv9 express$ 8 belief t life's process is electrical & t !re is a =ce inh]5t to ! organism & det]m9+ its motions4 ,j z mu* z ,i am conv9c$ ( any physical tru? ,i am conv9c$ t ! motive impulse mu/ come f ! outside4 ,=1 consid] ! l[e/ organism we "k--& !re are probably _m l[] ones--an aggregation ( a few cells only4 ,if x is capable ( volunt>y motion x c p]=m an inf9ite numb] ( motions1 all def9ite & precise4 ,b n[ a me*anism consi/+ ( a f9ite numb] ( p>ts & few at t1 _c p]=m an inf9ite numb] ( def9ite motions1 h5ce ! impulses :i* gov]n its movem5ts mu/ come f ! environm5t4 ,s1 ! atom1 ! ult]ior elem5t ( ! ,univ]se's /ructure1 is toss$ ab\t 9 space1 et]nally1 a play to ext]nal influ5ces1 l a boat 9 a tr\bl$ sea4 ,7 x to /op its motion x w\ld die4 ,matt] at re/1 if su* a ?+ c\ld exi/1 w\ld be matt] dead4 ,dea? ( matt]6 ,nev] has a s5t5ce ( deep] philosophical mean+ be5 utt]$4 ,?is is ! way 9 :i* ,pr(4 ,dew> =cibly expresses x 9 ! description ( 8 admirable exp]im5ts1 9 :i* liquid oxyg5 is h&l$ z "o h&les wat]1 & air at ord9>y pressure is made to cond5se & ev5 to solidify by ! int5se cold4 ,exp]im5ts1 :i* s]ve to illu/rate1 9 8 language1 ! la/ feeble manife/ations ( life1 ! la/ quiv]+s ( matt] ab\t to die4 ,b human eyes %all n witness su* dea?4 ,!re is no dea? ( matt]1 = ?r\gh\t ! inf9ite univ]se1 all has to move1 to vibrate1 t is1 to live4 ,i h made ! prec$+ /atem5ts at ! p]il ( tread+ ^u metaphysical gr\nd1 9 my desire to introduce ! subject ( ?is lecture 9 a mann] n altoge!r un9t]e/+1 ,i may hope1 to an audi5ce su* z ,i h ! honor to address4 ,b n[1 !n1 return+ to ! subject1 ?is div9e organ ( sight1 ?is indisp5sable in/rum5t = ?\ght & all intellectual enjoym5t1 :i* lays op5 to u ! m>vels ( ?is univ]se1 ?r\gh :i* we h acquir$ :at k we possess1 & :i* prompts u to1 & controls1 all our physical & m5tal activity4 ,by :at is x affect$8 ,by light6 ,:at is light8 ,we h witness$ ! great /rides :i* h be5 made 9 all dep>tm5ts ( sci5ce 9 rec5t ye>s4 ,s great h be5 ! advances t we _c refra9 f ask+ ourselves1 ,is ?is all true1 or is x b a dream8 ,c5turies ago m5 h liv$1 h ?\ght1 discov]$1 inv5t$1 & h believ$ t !y 7 so>+1 :ile !y 7 m]ely proce$+ at a snail's pace4 ,s we too may be mi/ak54 ,b tak+ ! tru? ( ! obs]v$ ev5ts z "o ( ! impli$ facts ( sci5ce1 we mu/ rejoice 9 ! imm5se progress already made & /ill m 9 ! anticipation ( :at mu/ come1 judg+ f ! possibilities op5$ up by mod]n rese>*4 ,!re is1 h[ev]1 an advance :i* we h be5 witness+1 :i* mu/ be p>ticul>ly gratify+ to e lov] ( progress4 ,x is n a discov]y1 or an inv5tion1 or an a*ievem5t 9 any p>ticul> direction4 ,x is an advance 9 all directions ( sci5tific ?\ght & exp]im5t4 ,i mean ! g5]alization ( ! natural =ces & ph5om5a1 ! loom+ up ( a c]ta9 broad idea on ! sci5tific horizon4 ,x is ?is idea :i* has1 h[ev]1 long ago tak5 possession ( ! mo/ advanc$ m9ds1 to :i* ,i desire to call y\r att5tion1 & :i* ,i int5d to illu/rate 9 a g5]al way1 9 ^! exp]im5ts1 z ! fir/ /ep 9 answ]+ ! "q ,:at is light8 & to realize ! mod]n mean+ ( ?is ^w4 ,x is beyond ! scope ( my lecture to dwell ^u ! subject ( light 9 g5]al1 my object be+ m]ely to br+ pres5tly to y\r notice a c]ta9 class ( light effects & a numb] ( ph5om5a obs]v$ 9 pursu+ ! /udy ( ^! effects4 ,b to be consi/5t 9 my rem>ks x is necess>y to /ate t1 accord+ to t idea1 n[ accept$ by ! majority ( sci5tific m5 z a positive result ( !oretical & exp]im5tal inve/igation1 ! v>i\s =ms or manife/ations ( en]gy :i* 7 g5]ally designat$ z electric or m precisely electromagnetic are en]gy manife/ations ( ! same nature z ^? ( radiant heat & light4 ,!re=e ! ph5om5a ( light & heat & o!rs besides ^!1 may be call$ electrical ph5om5a4 ,?us electrical sci5ce has become ! "m sci5ce ( all & its /udy has become all important4 ,! day :5 we %all "k exactly :at electricity is1 w *ronicle an ev5t probably great]1 m important ?an any o!r record$ 9 ! hi/ory ( ! human race4 ,! "t w come :5 ! com=t1 ! v exi/5ce1 p]haps1 ( man w dep5d ^u t wond]ful ag5t4 ,= our exi/5ce & com=t we require heat1 light & me*anical p[]4 ,h[ d we n[ get all ^!8 ,we get !m f fuel1 we get !m by consum+ mat]ial4 ,:at w man d :5 ! =e/s disappe>1 :5 ! coal fields are exhau/$8 ,only "o ?+1 accord+ to our pres5t k w rema92 t is1 to transmit p[] at great di/ances4 ,m5 w g to ! wat]falls1 to ! tides1 :i* are ! /ores ( an inf9itesimal "p ( ,nature's immeasurable en]gy4 ,!re w !y h>ness ! en]gy & transmit ! same to _! settlem5ts1 to w>m _! homes by1 to give !m light1 & to keep _! ob$i5t slaves1 ! ma*9es1 toil+4 ,b h[ w !y transmit ?is en]gy if n by electricity8 ,judge !n1 if ! com=t1 nay1 ! v exi/5ce1 ( man w n dep5d on electricity4 ,i am aw>e t ?is view is n t ( a practical eng9e]1 b nei!r is x t ( an illusioni/1 = x is c]ta91 t p[] transmission1 :i* at pres5t is m]ely a /imulus to ent]prise1 w "s day be a dire necessity4 ,x is m important = ! /ud5t1 :o takes up ! /udy ( light ph5om5a1 to make himself ?or\ghly acqua9t$ ) c]ta9 mod]n views1 ?an to p]use entire books on ! subject ( light itself1 z disconnect$ f ^! views4 ,7 ,i !re=e to make ^! demon/rations be=e /ud5ts seek+ in=mation--& = ! sake ( ! few ( ^? :o may be pres5t1 give me leave to s assume--x w\ld be my pr9cipal endeavor to impress ^! views ^u _! m9ds 9 ?is s]ies ( exp]im5ts4 ,x might be suffici5t = ?is purpose to p]=m a simple & well-kn[n exp]im5t4 ,i might take a famili> appliance1 a ,leyd5 j>1 *>ge x f a frictional ma*9e1 & !n dis*>ge x4 ,9 expla9+ to y its p]man5t /ate :5 *>g$1 & its transitory condition :5 dis*>g+1 call+ y\r att5tion to ! =ces :i* ent] into play & to ! v>i\s ph5om5a !y produce1 & po9t+ out ! relation ( ! =ces & ph5om5a1 ,i might fully succe$ 9 illu/rat+ t mod]n idea4 ,no d\bt1 to ! ?9k]1 ?is simple exp]im5t w\ld appeal z mu* z ! mo/ magnific5t display4 ,b ?is is to be an exp]im5tal demon/ration1 & "o :i* %\ld possess1 besides in/ructive1 also ent]ta9+ features & z su*1 a simple exp]im5t1 su* z ! "o cit$1 w\ld n g v f> t[>ds ! atta9m5t ( ! lectur]'s aim4 ,i mu/ !re=e *oose ano!r way ( illu/rat+1 m spectacul> c]ta9ly1 b p]haps also m in/ructive4 ,in/ead ( ! frictional ma*9e & ,leyd5 j>1 ,i %all avail myself 9 ^! exp]im5ts1 ( an induction coil ( peculi> prop]ties1 :i* 0 describ$ 9 detail by me 9 a lecture be=e ! ,london ,in/itution ( ,electrical ,eng9e]s1 9 ,feb41 #ahib4 ,?is induction coil is capable ( yield+ curr5ts ( enorm\s pot5tial diff]5ces1 alt]nat+ ) extreme rapidity4 ,) ?is app>atus ,i %all endeavor to %[ y ?ree di/9ct classes ( effects1 or ph5om5a1 & x is my desire t ea* exp]im5t1 :ile s]v+ = ! purposes ( illu/ration1 %\ld at ! same "t tea* u "s novel tru?1 or %[ u "s novel aspect ( ?is fasc9at+ sci5ce4 ,b be=e do+ ?is1 x seems prop] & useful to dwell ^u ! app>atus employ$1 & me?od ( obta9+ ! high pot5tials & high-frequ5cy curr5ts :i* are made use ( 9 ^! exp]im5ts4 ,illu/ration3 ,,fig4 #afe4 ,,on ,,! ,,app>atus ,,& ,,me?od ,,( ,,conv]sion4 ,^! high-frequ5cy curr5ts are obta9$ 9 a peculi> mann]4 ,! me?od employ$ 0 advanc$ by me ab\t two ye>s ago 9 an exp]im5tal lecture be=e ! ,am]ican ,in/itute ( ,electrical ,eng9e]s4 ,a numb] ( ways1 z practic$ 9 ! laboratory1 ( obta9+ ^! curr5ts ei!r f cont9u\s or l[ frequ5cy alt]nat+ curr5ts1 is diagramatically indicat$ 9 ,fig4 #afe1 :i* w be lat] describ$ 9 detail4 ,! g5]al plan is to *>ge cond5s]s1 f a direct or alt]nate-curr5t s\rce1 pref]ably ( high-t5sion1 & to dis*>ge !m disruptively :ile obs]v+ well-kn[n conditions necess>y to ma9ta9 ! oscillations ( ! curr5t4 ,9 view ( ! g5]al int]e/ tak5 9 high-frequ5cy curr5ts & effects producible by !m1 x seems to me advisable to dwell at "s l5g? ^u ?is me?od ( conv]sion4 ,9 ord] to give y a cle> idea ( ! action1 ,i w suppose t a cont9u\s-curr5t g5]ator is employ$1 :i* is (t5 v conv5i5t4 ,x is desirable t ! g5]ator %\ld possess su* high t5sion z to be able to break ?r\gh a small air space4 ,if ?is is n ! case1 !n auxili>y means h to be resort$ to1 "s ( :i* w be indicat$ subsequ5tly4 ,:5 ! cond5s]s are *>g$ to a c]ta9 pot5tial1 ! air1 or insulat+ space1 gives way & a disruptive dis*>ge occurs4 ,!re is !n a sudd5 ru% ( curr5t & g5]ally a l>ge portion ( accumulat$ electrical en]gy sp5ds itself4 ,! cond5s]s are !reupon quickly *>g$ & ! same process is repeat$ 9 m or less rapid succession4 ,to produce su* sudd5 ru%es ( curr5t x is necess>y to obs]ve c]ta9 conditions4 ,if ! rate at :i* ! cond5s]s are dis*>g$ is ! same z t at :i* !y are *>g$1 !n1 cle>ly1 9 ! assum$ case ! cond5s]s d n come into play4 ,if ! rate ( dis*>ge be small] ?an ! rate ( *>g+1 !n1 aga91 ! cond5s]s _c play an important "p4 ,b if1 on ! contr>y1 ! rate ( dis*>g+ is great] ?an t ( *>g+1 !n a succession ( ru%es ( curr5t is obta9$4 ,x is evid5t t1 if ! rate at :i* ! en]gy is dissipat$ by ! dis*>ge is v mu* great] ?an ! rate ( supply to ! cond5s]s1 ! sudd5 ru%es w be comp>atively few1 ) long-"t int]vals betwe54 ,?is always occurs :5 a cond5s] ( consid]able capacity is *>g$ by means ( a comp>atively small ma*9e4 ,if ! rates ( supply & dissipation are n widely diff]5t1 !n ! ru%es ( curr5t w be 9 quick] succession1 & ?is ! m1 ! m ne>ly equal bo? ! rates are1 until limitations incid5t to ea* case & dep5d+ ^u a numb] ( causes are rea*$4 ,?us we are able to obta9 f a cont9u\s-curr5t g5]ator z rapid a succession ( dis*>ges z we l4 ,( c\rse1 ! high] ! t5sion ( ! g5]ator1 ! small] ne$ be ! capacity ( ! cond5s]s1 & = ?is reason1 pr9cipally1 x is ( advantage to employ a g5]ator ( v high t5sion4 ,besides1 su* a g5]ator p]mits ! atta9+ ( great] rates ( vibration4 ,! ru%es ( curr5t may be ( ! same direction "u ! conditions be=e assum$1 b mo/ g5]ally !re is an oscillation sup]impos$ ^u ! fundam5tal vibration ( ! curr5t4 ,:5 ! conditions are s det]m9$ t !re are no oscillations1 ! curr5t impulses are unidirectional & ?us a means is provid$ ( trans=m+ a cont9u\s curr5t ( high t5sion1 into a direct curr5t ( l[] t5sion1 :i* ,i ?9k may f9d employm5t 9 ! arts4 ,?is me?od ( conv]sion is exce$+ly int]e/+ & ,i 0 mu* impress$ by its beauty :5 ,i fir/ conceiv$ x4 ,x is ideal 9 c]ta9 respects4 ,x involves ! employm5t ( no me*anical devices ( any k9d1 & x all[s ( obta9+ curr5ts ( any desir$ frequ5cy f an ord9>y circuit1 direct or alt]nat+4 ,! frequ5cy ( ! fundam5tal dis*>ges dep5d+ on ! relative rates ( supply & dissipation c be readily v>i$ )9 wide limits1 by simple adju/m5ts ( ^! quantities1 & ! frequ5cy ( ! sup]impos$ vibration by ! det]m9ation ( ! capacity1 self-induction & resi/ance ( ! circuit4 ,! pot5tial ( ! curr5ts1 aga91 may be rais$ z high z any insulation is capable ( )/&+ safely by comb9+ capacity & self-induction or by induction 9 a second>y1 :i* ne$ h b comp>atively few turns4 ,z ! conditions are (t5 su* t ! int]mitt5ce or oscillation does n readily e/abli% itself1 especially :5 a direct curr5t s\rce is employ$1 x is ( advantage to associate an int]rupt] ) ! arc1 z ,i h1 "s "t ago1 indicat$ ! use ( an air-bla/ or magnet1 or o!r su* device readily at h&4 ,! magnet is employ$ ) special advantage 9 ! conv]sion ( direct curr5ts1 z x is !n v effective4 ,if ! prim>y s\rce is an alt]nate curr5t g5]ator1 x is desirable1 z ,i h /at$ on ano!r occasion1 t ! frequ5cy %\ld be l[1 & t ! curr5t =m+ ! arc be l>ge1 9 ord] to r5d] ! magnet m effective4 ,a =m ( su* dis*>g] ) a magnet :i* has be5 f\nd conv5i5t1 & adopt$ aft] "s trials1 9 ! conv]sion ( direct curr5ts p>ticul>ly1 is illu/rat$ 9 ,fig4 #aff4 ,n ,s are ! pole pieces ( a v /rong magnet :i* is excit$ by a coil ,c4 ,! pole pieces are slott$ = adju/m5t & c be fa/5$ 9 any position by screws s s#a4 ,! dis*>ge rods d d#a1 ?9n$ d[n on ! ends 9 ord] to all[ a clos] approa* ( ! magnetic pole pieces1 pass ?r\gh ! columns ( brass b b#a & are fa/5$ 9 position by screws s#b s#b4 ,spr+s r r#a & coll>s c c#a are slipp$ on ! rods1 ! latt] s]v+ to set ! po9ts ( ! rods at a c]ta9 suitable di/ance by means ( screws s#c s#c1 & ! =m] to draw ! po9ts ap>t4 ,:5 x is desir$ to />t ! arc1 "o ( ! l>ge rubb] h&les h h#a is tapp$ quickly ) ! h&1 :]eby ! po9ts ( ! rods are br\ght 9 contact b are in/antly sep>at$ by ! spr+s r r#a4 ,su* an arrangem5t has be5 f\nd to be (t5 necess>y1 namely 9 cases :5 ! ,e4 ,m4 ,f4 0 n l>ge en\gh to cause ! dis*>ge to break ?r\gh ! gap1 & also :5 x 0 desirable to avoid %ort circuit+ ( ! g5]ator by ! metallic contact ( ! rods4 ,! rapidity ( ! int]ruptions ( ! curr5t ) a magnet dep5ds on ! int5sity ( ! magnetic field & on ! pot5tial diff]5ce at ! end ( ! arc4 ,! int]ruptions are g5]ally 9 su* quick succession z to produce a musical s\nd4 ,ye>s ago x 0 obs]v$ t :5 a p[]ful induction coil is dis*>g$ betwe5 ! poles ( a /rong magnet1 ! dis*>ge produces a l\d noise1 n unlike a small pi/ol %ot4 ,x 0 vaguely /at$ t ! sp>k 0 int5sifi$ by ! pres5ce ( ! magnetic field4 ,x is n[ cle> t ! dis*>ge curr5t1 fl[+ = "s "t1 0 int]rupt$ a great numb] ( times by ! magnet1 ?us produc+ ! s\nd4 ,! ph5om5on is especially m>k$ :5 ! field circuit ( a l>ge magnet or dynamo is brok5 9 a p[]ful magnetic field4 ,illu/ration3 ,,fig4 #aff4 ,:5 ! curr5t ?r\gh ! gap is comp>atively l>ge1 x is ( advantage to slip on ! po9ts ( ! dis*>ge rods pieces ( v h>d c>bon & let ! arc play betwe5 ! c>bon pieces4 ,?is pres]ves ! rods1 & besides has ! advantage ( keep+ ! air space hott]1 z ! heat is n conduct$ away z quickly ?r\gh ! c>bons1 & ! result is t a small] ,e4 ,m4 ,f4 9 ! arc gap is requir$ to ma9ta9 a succession ( dis*>ges4 ,illu/ration3 ,,fig4 #afg4 ,ano!r =m ( dis*>g]1 :i* may be employ$ ) advantage 9 "s cases1 is illu/rat$ 9 ,fig4 #afg4 ,9 ?is =m ! dis*>ge rods d d#a pass ?r\gh p]=ations 9 a wood5 box ,b1 :i* is ?ickly coat$ ) mica on ! inside1 z indicat$ by ! heavy l9es4 ,! p]=ations are provid$ ) mica tubes m m#a ( "s ?ickness1 :i* are pref]ably n 9 contact ) ! rods d d#a4 ,! box has a cov] ,c :i* is a little l>g] & desc5ds on ! outside ( ! box4 ,! sp>k gap is w>m$ by a small lamp l conta9$ 9 ! box4 ,a plate p above ! lamp all[s ! draught to pass only ?r\gh ! *imney e ( ! lamp1 ! air ent]+ ?r\gh holes o o 9 or ne> ! bottom ( ! box & foll[+ ! pa? indicat$ by ! arr[s4 ,:5 ! dis*>g] is 9 op]ation1 ! door ( ! box is clos$ s t ! light ( ! arc is n visible outside4 ,x is desirable to exclude ! light z p]fectly z possible1 z x int]f]es ) "s exp]im5ts4 ,?is =m ( dis*>g] is simple & v effective :5 prop]ly manipulat$4 ,! air be+ w>m$ to a c]ta9 temp]ature1 has its insulat+ p[] impair$2 x becomes dielectrically weak1 z x 71 & ! consequ5ce is t ! arc c be e/abli%$ at mu* great] di/ance4 ,! arc %\ld1 ( c\rse1 be suffici5tly insulat+ to all[ ! dis*>ge to pass ?r\gh ! gap disruptively4 ,! arc =m$ "u su* conditions1 :5 long1 may be made extremely s5sitive1 & ! weak draught ?r\gh ! lamp *imney c is q suffici5t to produce rapid int]ruptions4 ,! adju/m5t is made by regulat+ ! temp]ature & velocity ( ! draught4 ,in/ead ( us+ ! lamp1 x answ]s ! purpose to provide = a draught ( w>m air 9 o!r ways4 ,a v simple way :i* has be5 practic$ is to enclose ! arc 9 a long v]tical tube1 ) plates on ! top & bottom = regulat+ ! temp]ature & velocity ( ! air curr5t4 ,"s provision _h to be made = dead5+ ! s\nd4 ,! air may be r5d]$ dielectrically weak also by r>efaction4 ,dis*>g]s ( ?is k9d h likewise be5 us$ by me 9 connection ) a magnet4 ,a l>ge tube is = ?is purpose provid$ ) heavy electrodes ( c>bon or metal1 betwe5 :i* ! dis*>ge is made to pass1 ! tube be+ plac$ 9 a p[]ful magnetic field4 ,! exhau/ion ( ! tube is c>ri$ to a po9t at :i* ! dis*>ge breaks ?r\gh easily1 b ! pressure %\ld be m ?an #ge millimetres1 at :i* ! ord9>y ?read dis*>ge occurs4 ,9 ano!r =m ( dis*>g]1 comb9+ ! features be=e m5tion$1 ! dis*>ge 0 made to pass betwe5 two adju/able magnetic pole pieces1 ! space betwe5 !m be+ kept at an elevat$ temp]ature4 ,x %\ld be rem>k$ "h t :5 su*1 or int]rupt+ devices ( any k9d1 are us$ & ! curr5ts are pass$ ?r\gh ! prim>y ( a disruptive dis*>ge coil1 x is n1 z a rule1 ( advantage to produce a numb] ( int]ruptions ( ! curr5t p] second great] ?an ! natural frequ5cy ( vibration ( ! dynamo supply circuit1 :i* is ord9>ily small4 ,x %\ld also be po9t$ out "h1 t :ile ! devices m5tion$ 9 connection ) ! disruptive dis*>ge are advantage\s "u c]ta9 conditions1 !y may be sometimes a s\rce ( tr\ble1 z !y produce int]mitt5ces & o!r irregul>ities 9 ! vibration :i* x w\ld be v desirable to ov]come4 ,!re is1 ,i regret to say1 9 ?is beautiful me?od ( conv]sion a defect1 :i* =tunately is n vital1 & :i* ,i h be5 gradually ov]com+4 ,i w be/ call att5tion to ?is defect & indicate a fruitful l9e ( "w1 by comp>+ ! electrical process ) its me*anical analogue4 ,! process may be illu/rat$ 9 ?is mann]4 ,imag9e a tank ) a wide op5+ at ! bottom1 :i* is kept clos$ by spr+ pressure1 b s t x snaps (f sudd5ly :5 ! liquid 9 ! tank has rea*$ a c]ta9 height4 ,let ! fluid be suppli$ to ! tank by means ( a pipe fe$+ at a c]ta9 rate4 ,:5 ! critical height ( ! liquid is rea*$1 ! spr+ gives way & ! bottom ( ! tank drops out4 ,in/antly ! liquid falls ?r\gh ! wide op5+1 & ! spr+1 reass]t+ itself1 closes ! bottom aga94 ,! tank is n[ fill$1 & aft] a c]ta9 "t int]val ! same process is repeat$4 ,x is cle>1 t if ! pipe fe$s ! fluid quick] ?an ! bottom outlet is capable ( lett+ x pass ?r\gh1 ! bottom w rema9 (f & ! tank w /ill ov]fl[4 ,if ! rates ( supply are exactly equal1 !n ! bottom lid w rema9 p>tially op5 & no vibration ( ! same & ( ! liquid column w g5]ally occur1 ?\gh x might1 if />t$ by "s means4 ,b if ! inlet pipe does n fe$ ! fluid fa/ en\gh = ! outlet1 !n !re w be always vibration4 ,aga91 9 su* case1 ea* "t ! bottom flaps up or d[n1 ! spr+ & ! liquid column1 if ! pliability ( ! spr+ & ! in]tia ( ! mov+ p>ts are prop]ly *os51 w p]=m indep5d5t vibrations4 ,9 ?is analogue ! fluid may be lik5$ to electricity or electrical en]gy1 ! tank to ! cond5s]1 ! spr+ to ! dielectric1 & ! pipe to ! conductor ?r\gh :i* electricity is suppli$ to ! cond5s]4 ,to make ?is analogy q complete x is necess>y to make ! assumption1 t ! bottom1 ea* "t x gives way1 is knock$ viol5tly aga9/ a non-ela/ic /op1 ?is impact involv+ "s loss ( en]gy2 & t1 besides1 "s dissipation ( en]gy results due to frictional losses4 ,9 ! prec$+ analogue ! liquid is suppos$ to be "u a /eady pressure4 ,if ! pres5ce ( ! fluid be assum$ to v>y rhy?mically1 ?is may be tak5 z correspond+ to ! case ( an alt]nat+ curr5t4 ,! process is !n n q z simple to consid]1 b ! action is ! same 9 pr9ciple4 ,x is desirable1 9 ord] to ma9ta9 ! vibration economically1 to r$uce ! impact & frictional losses z mu* z possible4 ,z reg>ds ! latt]1 :i* 9 ! electrical analogue correspond to ! losses due to ! resi/ance ( ! circuits1 x is impossible to obviate !m entirely1 b !y c be r$uc$ to a m9imum by a prop] selection ( ! dim5sions ( ! circuits & by ! employm5t ( ?9 conductors 9 ! =m ( /r&s4 ,b ! loss ( en]gy caus$ by ! fir/ break+ ?r\gh ( ! dielectric--:i* 9 ! above example corresponds to ! viol5t knock ( ! bottom aga9/ ! inela/ic /op--w\ld be m important to ov]come4 ,at ! mom5t ( ! break+ ?r\gh1 ! air space has a v high resi/ance1 :i* is probably r$uc$ to a v small value :5 ! curr5t has rea*$ "s /r5g?1 & ! space is br\ght to a high temp]ature4 ,x w\ld mat]ially dim9i% ! loss ( en]gy if ! space 7 always kept at an extremely high temp]ature1 b !n !re w\ld be no disruptive break4 ,by w>m+ ! space mod]ately by means ( a lamp or o!rwise1 ! economy z f> z ! arc is conc]n$ is s5sibly increas$4 ,b ! magnet or o!r int]rupt+ device does n dim9i% ! loss 9 ! arc4 ,likewise1 a jet ( air only facilitates ! c>ry+ (f ( ! en]gy4 ,air1 or a gas 9 g5]al1 behaves curi\sly 9 ?is respect4 ,:5 two bodies *>g$ to a v high pot5tial1 dis*>ge disruptively ?r\gh an air space1 any am\nt ( en]gy may be c>ri$ (f by ! air4 ,?is en]gy is evid5tly dissipat$ by bodily c>ri]s1 9 impact & collisional losses ( ! molecules4 ,! ex*ange ( ! molecules 9 ! space occurs ) inconceivable rapidity4 ,a p[]ful dis*>ge tak+ place betwe5 two electrodes1 !y may rema9 entirely cool1 & yet ! loss 9 ! air may repres5t any am\nt ( en]gy4 ,x is p]fectly practicable1 ) v great pot5tial diff]5ces 9 ! gap1 to dissipate sev]al horse-p[] 9 ! arc ( ! dis*>ge )\t ev5 notic+ a small increase 9 ! temp]ature ( ! electrodes4 ,all ! frictional losses occur !n practically 9 ! air4 ,if ! ex*ange ( ! air molecules is prev5t$1 z by enclos+ ! air h]metically1 ! gas inside ( ! vessel is br\ght quickly to a high temp]ature1 ev5 ) a v small dis*>ge4 ,x is difficult to e/imate h[ mu* ( ! en]gy is lo/ 9 s\nd waves1 audible or n1 9 a p[]ful dis*>ge4 ,:5 ! curr5ts ?r\gh ! gap are l>ge1 ! electrodes may become rapidly heat$1 b ?is is n a reliable measure ( ! en]gy wa/$ 9 ! arc1 z ! loss ?r\gh ! gap itself may be comp>atively small4 ,! air or a gas 9 g5]al is1 at ord9>y pressure at lea/1 cle>ly n ! be/ m$ium ?r\gh :i* a disruptive dis*>ge %\ld occur4 ,air or o!r gas "u great pressure is ( c\rse a mu* m suitable m$ium = ! dis*>ge gap4 ,i h c>ri$ on long-cont9u$ exp]im5ts 9 ?is direction1 un=tunately less practicable on acc\nt ( ! difficulties & exp5se 9 gett+ air "u great pressure4 ,b ev5 if ! m$ium 9 ! dis*>ge space is solid or liquid1 /ill ! same losses take place1 ?\gh !y are g5]ally small]1 = j z soon z ! arc is e/abli%$1 ! solid or liquid is volatiliz$4 ,inde$1 !re is no body kn[n :i* w\ld n be dis9tegrat$ by ! arc1 & x is an op5 "q among sci5tific m51 :e!r an arc dis*>ge c\ld occur at all 9 ! air itself )\t ! p>ticles ( ! electrodes be+ torn (f4 ,:5 ! curr5t ?r\gh ! gap is v small & ! arc v long1 ,i believe t a relatively consid]able am\nt ( heat is tak5 up 9 ! dis9tegration ( ! electrodes1 :i* p>tially on ?is acc\nt may rema9 q cold4 ,! ideal m$ium = a dis*>ge gap %\ld only crack1 & ! ideal electrode %\ld be ( "s mat]ial :i* _c be dis9tegrat$4 ,) small curr5ts ?r\gh ! gap x is be/ to employ alum9um1 b n :5 ! curr5ts are l>ge4 ,! disruptive break 9 ! air1 or m or less 9 any ord9>y m$ium1 is n ( ! nature ( a crack1 b x is r comp>able to ! pi]c+ ( innum]able bullets ?r\gh a mass (f]+ great frictional resi/ances to ! motion ( ! bullets1 ?is involv+ consid]able loss ( en]gy4 ,a m$ium :i* w\ld m]ely crack :5 /ra9$ electro/atically--& ?is possibly might be ! case ) a p]fect vacuum1 t is1 pure e!r--w\ld involve a v small loss 9 ! gap1 s small z to be entirely negligible1 at lea/ !oretically1 because a crack may be produc$ by an inf9itely small displacem5t4 ,9 exhau/+ an oblong bulb provid$ ) two alum9um t]m9als1 ) ! greate/ c>e1 ,i h succe$$ 9 produc+ su* a vacuum t ! second>y dis*>ge ( a disruptive dis*>ge coil w\ld break disruptively ?r\gh ! bulb 9 ! =m ( f9e sp>k /reams4 ,! curi\s po9t 0 t ! dis*>ge w\ld completely ignore ! t]m9als & />t f> beh9d ! two alum9um plates :i* s]v$ z electrodes4 ,?is extraord9>y high vacuum c\ld only be ma9ta9$ = a v %ort :ile4 ,to return to ! ideal m$ium1 ?9k1 = ! sake ( illu/ration1 ( a piece ( glass or simil> body clamp$ 9 a vice1 & ! latt] tight5$ m & m4 ,at a c]ta9 po9t a m9ute increase ( ! pressure w cause ! glass to crack4 ,! loss ( en]gy involv$ 9 splitt+ ! glass may be practically no?+1 = ?\gh ! =ce is great1 ! displacem5t ne$ be b extremely small4 ,n[ imag9e t ! glass w\ld possess ! prop]ty ( clos+ aga9 p]fectly ! crack ^u a m9ute dim9ution ( ! pressure4 ,?is is ! way ! dielectric 9 ! dis*>ge space %\ld behave4 ,b inasmu* z !re w\ld be always "s loss 9 ! gap1 ! m$ium1 :i* %\ld be cont9u\s1 %\ld ex*ange ?r\gh ! gap at a rapid rate4 ,9 ! prec$+ example1 ! glass be+ p]fectly clos$1 x w\ld mean t ! dielectric 9 ! dis*>ge space possesses a great insulat+ p[]2 ! glass be+ crack$1 x w\ld signify t ! m$ium 9 ! space is a good conductor4 ,! dielectric %\ld v>y enorm\sly 9 resi/ance by m9ute v>iations ( ! ,e4 ,m4 ,f4 across ! dis*>ge space4 ,?is condition is atta9$1 b 9 an extremely imp]fect mann]1 by w>m+ ! air space to a c]ta9 critical temp]ature1 dep5d5t on ! ,e4 ,m4 ,f4 across ! gap1 or by o!rwise impair+ ! insulat+ p[] ( ! air4 ,b z a matt] ( fact ! air does nev] break d[n disruptively1 if ?is t]m be rigor\sly int]pret$1 = be=e ! sudd5 ru% ( ! curr5t occurs1 !re is always a weak curr5t prec$+ x1 :i* rises fir/ gradually & !n ) comp>ative sudd5ness4 ,t is ! reason :y ! rate ( *ange is v mu* great] :5 glass1 = in/ance1 is brok5 ?r\gh1 ?an :5 ! break takes place ?r\gh an air space ( equival5t dielectric /r5g?4 ,z a m$ium = ! dis*>ge space1 a solid1 or ev5 a liquid1 w\ld be pref]able !re=4 ,x is some:at difficult to conceive ( a solid body :i* w\ld possess ! prop]ty ( clos+ in/antly aft] x has be5 crack$4 ,b a liquid1 especially "u great pressure1 behaves practically l a solid1 :ile x possesses ! prop]ty ( clos+ ! crack4 ,h5ce x 0 ?\ght t a liquid insulator might be m suitable z a dielectric ?an air4 ,foll[+ out ?is idea1 a numb] ( diff]5t =ms ( dis*>g]s 9 :i* a v>iety ( su* insulators1 sometimes "u great pressure1 7 employ$1 h be5 exp]im5t$ ^u4 ,x is ?\ght suffici5t to dwell 9 a few words ^u "o ( ! =ms exp]im5t$ ^u4 ,"o ( ^! dis*>g]s is illu/rat$ 9 ,figs4 #afh;a & #afh;b4 ,illu/ration3 ,,fig4 #afh;a4 ,illu/ration3 ,,fig4 #afh;b4 ,a holl[ metal pulley ,p 7,fig4 #afh;a71 0 fa/5$ ^u an arbor a1 :i* by suitable means 0 rotat$ at a consid]able spe$4 ,on ! inside ( ! pulley1 b disconnect$ f ! same1 0 support$ a ?9 disc h 7:i* is %[n ?ick = ! sake ( cle>ness71 ( h>d rubb] 9 :i* !re 7 emb$d$ two metal segm5ts s s ) metallic ext5sions e e into :i* 7 screw$ conduct+ t]m9als t t cov]$ ) ?ick tubes ( h>d rubb] t t4 ,! rubb] disc h ) its metallic segm5ts s s1 0 f9i%$ 9 a la!1 & its entire surface highly poli%$ s z to (f] ! smalle/ possible frictional resi/ance to ! motion ?r\gh a fluid4 ,9 ! holl[ ( ! pulley an insulat+ liquid su* z a ?9 oil 0 p\r$ s z to rea* v ne>ly to ! op5+ left 9 ! flange f1 :i* 0 screw$ tightly on ! front side ( ! pulley4 ,! t]m9als t t1 7 connect$ to ! opposite coat+s ( a batt]y ( cond5s]s s t ! dis*>ge occurr$ ?r\gh ! liquid4 ,:5 ! pulley 0 rotat$1 ! liquid 0 =c$ aga9/ ! rim ( ! pulley & consid]able fluid pressure result$4 ,9 ?is simple way ! dis*>ge gap 0 fill$ ) a m$ium :i* behav$ practically l a solid1 :i* possess$ ! quality ( clos+ in/antly ^u ! occurr5ce ( ! break1 & :i* moreov] 0 circulat+ ?r\gh ! gap at a rapid rate4 ,v p[]ful effects 7 produc$ by dis*>ges ( ?is k9d ) liquid int]rupt]s1 ( :i* a numb] ( diff]5t =ms 7 made4 ,x 0 f\nd t1 z expect$1 a long] sp>k = a giv5 l5g? ( wire 0 obta9able 9 ?is way ?an by us+ air z an int]rupt+ device4 ,g5]ally ! spe$1 & !re=e also ! fluid pressure1 0 limit$ by reason ( ! fluid friction1 9 ! =m ( dis*>g] describ$1 b ! practically obta9able spe$ 0 m ?an suffici5t to produce a numb] ( breaks suitable = ! circuits ord9>ily us$4 ,9 su* in/ances ! metal pulley ,p 0 provid$ ) a few projections inw>dly1 & a def9ite numb] ( breaks 0 !n produc$ :i* c\ld be comput$ f ! spe$ ( rotation ( ! pulley4 ,exp]im5ts 7 also c>ri$ on ) liquids ( diff]5t insulat+ p[] ) ! view ( r$uc+ ! loss 9 ! arc4 ,:5 an insulat+ liquid is mod]ately w>m$1 ! loss 9 ! arc is dim9i%$4 ,a po9t ( "s importance 0 not$ 9 exp]im5ts ) v>i\s dis*>ges ( ?is k9d4 ,x 0 f\nd1 = in/ance1 t :]eas ! conditions ma9ta9$ 9 ^! =ms 7 favorable = ! production ( a great sp>k l5g?1 ! curr5t s obta9$ 0 n be/ suit$ to ! production ( light effects4 ,exp]i5ce und\bt$ly has %[n1 t = su* purposes a h>monic rise & fall ( ! pot5tial is pref]able4 ,be x t a solid is r5d]$ inc&esc5t1 or phosphoresc5t1 or be x t en]gy is transmitt$ by cond5s] coat+ ?r\gh ! glass1 x is q c]ta9 t a h>monically ris+ & fall+ pot5tial produces less de/ructive action1 & t ! vacuum is m p]man5tly ma9ta9$4 ,?is w\ld be easily expla9$ if x 7 asc]ta9$ t ! process go+ on 9 an exhau/$ vessel is ( an electrolytic nature4 ,9 ! diagrammatical sket*1 ,fig4 #afe1 :i* has be5 already ref]r$ to1 ! cases :i* are mo/ likely to be met ) 9 practice are illu/rat$4 ,"o has at 8 disposal ei!r direct or alt]nat+ curr5ts f a supply /ation4 ,x is conv5i5t = an exp]im5t] 9 an isolat$ laboratory to employ a ma*9e ,g1 su* z illu/rat$1 capable ( giv+ bo? k9ds ( curr5ts4 ,9 su* case x is also pref]able to use a ma*9e ) multiple circuits1 z 9 _m exp]im5ts x is useful & conv5i5t to h at "o's disposal curr5ts ( diff]5t phases4 ,9 ! sket*1 ,d repres5ts ! direct & ,a ! alt]nat+ circuit4 ,9 ea* ( ^!1 ?ree bran* circuits are %[n1 all ( :i* are provid$ ) d\ble l9e swit*es s s s s s s4 ,consid] fir/ ! direct curr5t conv]sion2 ,ia repres5ts ! simple/ case4 ,if ! ,e4 ,m4 ,f4 ( ! g5]ator is suffici5t to break ?r\gh a small air space1 at lea/ :5 ! latt] is w>m$ or o!rwise r5d]$ poorly insulat+1 !re is no difficulty 9 ma9ta9+ a vibration ) fair economy by judici\s adju/m5t ( ! capacity1 self-induction & resi/ance ( ! circuit ,l conta9+ ! devices l l m4 ,! magnet ,n1 ,s1 c be 9 ?is case advantage\sly comb9$ ) ! air space4 ,! dis*>g] d d ) ! magnet may be plac$ ei!r way1 z indicat$ by ! full or by ! dott$ l9es4 ,! circuit ,ia ) ! connections & devices is suppos$ to possess dim5sions su* z are suitable = ! ma9t5ance ( a vibration4 ,b usually ! ,e4 ,m4 ,f4 on ! circuit or bran* ,ia w be some?+ l a #ajj volts or s1 & 9 ?is case x is n suffici5t to break ?r\gh ! gap4 ,_m diff]5t means may be us$ to rem$y ?is by rais+ ! ,e4 ,m4 ,f4 across ! gap4 ,! simple/ is probably to ins]t a l>ge self-induction coil 9 s]ies ) ! circuit ,l4 ,:5 ! arc is e/abli%$1 z by ! dis*>g] illu/rat$ 9 ,fig4 #aff1 ! magnet bl[s ! arc out ! in/ant x is =m$4 ,n[ ! extra curr5t ( ! break1 be+ ( high ,e4 ,m4 ,f41 breaks ?r\gh ! gap1 & a pa? ( l[ resi/ance = ! dynamo curr5t be+ aga9 provid$1 !re is a sudd5 ru% ( curr5t f ! dynamo ^u ! weak5+ or subsid5ce ( ! extra curr5t4 ,?is process is repeat$ 9 rapid succession1 & 9 ?is mann] ,i h ma9ta9$ oscillation ) z l[ z #ej volts1 or ev5 less1 across ! gap4 ,b conv]sion on ?is plan is n to be recomm5d$ on acc\nt ( ! too heavy curr5ts ?r\gh ! gap & consequ5t heat+ ( ! electrodes2 besides1 ! frequ5cies obta9$ 9 ?is way are l[1 ow+ to ! high self-induction necess>ily associat$ ) ! circuit4 ,x is v desirable to h ! ,e4 ,m4 ,f4 z high z possible1 fir/1 9 ord] to increase ! economy ( ! conv]sion1 &1 secondly1 to obta9 high frequ5cies4 ,! diff]5ce ( pot5tial 9 ?is electric oscillation is1 ( c\rse1 ! equival5t ( ! /ret*+ =ce 9 ! me*anical vibration ( ! spr+4 ,to obta9 v rapid vibration 9 a circuit ( "s in]tia1 a great /ret*+ =ce or diff]5ce ( pot5tial is necess>y4 ,incid5tally1 :5 ! ,e4 ,m4 ,f4 is v great1 ! cond5s] :i* is usually employ$ 9 connection ) ! circuit ne$ b h a small capacity1 & _m o!r advantages are ga9$4 ,) a view ( rais+ ! ,e4 ,m4 ,f4 to a _m times great] value ?an obta9able f ord9>y di/ribution circuits1 a rotat+ trans=m] g is us$1 z indicat$ at ,,iia1 ,fig4 #afe1 or else a sep>ate high pot5tial ma*9e is driv5 by means ( a motor op]at$ f ! g5]ator ,g4 ,! latt] plan is 9 fact pref]able1 z *anges are easi] made4 ,! connections f ! high t5sion w9d+ are q simil> to ^? 9 bran* ,ia ) ! exception t a cond5s] ,c1 :i* %\ld be adju/able1 is connect$ to ! high t5sion circuit4 ,usually1 also1 an adju/able self-induction coil 9 s]ies ) ! circuit has be5 employ$ 9 ^! exp]im5ts4 ,:5 ! t5sion ( ! curr5ts is v high1 ! magnet ord9>ily us$ 9 connection ) ! dis*>g] is ( comp>atively small value1 z x is q easy to adju/ ! dim5sions ( ! circuit s t oscillation is ma9ta9$4 ,! employm5t ( a /eady ,e4 ,m4 ,f4 9 ! high frequ5cy conv]sion af=ds "s advantages ov] ! employm5t ( alt]nat+ ,e4 ,m4 ,f41 z ! adju/m5ts are mu* simpl] & ! action c be easi] controll$4 ,b un=tunately "o is limit$ by ! obta9able pot5tial diff]5ce4 ,! w9d+ also breaks d[n easily 9 consequ5ce ( ! sp>ks :i* =m betwe5 ! sections ( ! armature or commutator :5 a vigor\s oscillation takes place4 ,besides1 ^! trans=m]s are exp5sive to build4 ,x has be5 f\nd by exp]i5ce t x is be/ to foll[ ! plan illu/rat$ at ,,iiia4 ,9 ?is arrangem5t a rotat+ trans=m] g1 is employ$ to conv]t ! l[ t5sion direct curr5ts into l[ frequ5cy alt]nat+ curr5ts1 pref]ably also ( small t5sion4 ,! t5sion ( ! curr5ts is !n rais$ 9 a /ation>y trans=m] ,t4 ,! second>y ,s ( ?is trans=m] is connect$ to an adju/able cond5s] ,c :i* dis*>ges ?r\gh ! gap or dis*>g] d d1 plac$ 9 ei!r ( ! ways indicat$1 ?r\gh ! prim>y ,p ( a disruptive dis*>ge coil1 ! high frequ5cy curr5t be+ obta9$ f ! second>y ,s ( ?is coil1 z describ$ on previ\s occasions4 ,?is w und\bt$ly be f\nd ! *eape/ & mo/ conv5i5t way ( conv]t+ direct curr5ts4 ,! ?ree bran*es ( ! circuit ,a repres5t ! usual cases met 9 practice :5 alt]nat+ curr5ts are conv]t$4 ,9 ,fig4 #a;b a cond5s] ,c1 g5]ally ( l>ge capacity1 is connect$ to ! circuit ,l conta9+ ! devices l l1 m m4 ,! devices m m are suppos$ to be ( high self-induction s z to br+ ! frequ5cy ( ! circuit m or less to t ( ! dynamo4 ,9 ?is in/ance ! dis*>g] d d %\ld be/ h a numb] ( makes & breaks p] second equal to twice ! frequ5cy ( ! dynamo4 ,if n s1 !n x %\ld h at lea/ a numb] equal to a multiple or ev5 fraction ( ! dynamo frequ5cy4 ,x %\ld be obs]v$1 ref]r+ to ,ib1 t ! conv]sion to a high pot5tial is also effect$ :5 ! dis*>g] d d1 :i* is %[n 9 ! sket*1 is omitt$4 ,b ! effects :i* are produc$ by curr5ts :i* rise in/antly to high values1 z 9 a disruptive dis*>ge1 are entirely diff]5t f ^? produc$ by dynamo curr5ts :i* rise & fall h>monically4 ,s1 = in/ance1 !re might be 9 a giv5 case a numb] ( makes & breaks at d d equal to j twice ! frequ5cy ( ! dynamo1 or 9 o!r words1 !re may be ! same numb] ( fundam5tal oscillations z w\ld be produc$ )\t ! dis*>ge gap1 & !re might ev5 n be any quick] sup]impos$ vibration2 yet ! diff]5ces ( pot5tial at ! v>i\s po9ts ( ! circuit1 ! imp$ance & o!r ph5om5a1 dep5d5t ^u ! rate ( *ange1 w be> no simil>ity 9 ! two cases4 ,?us1 :5 work+ ) curr5ts dis*>g+ disruptively1 ! elem5t *iefly to be consid]$ is n ! frequ5cy1 z a /ud5t might be apt to believe1 b ! rate ( *ange p] unit ( "t4 ,) l[ frequ5cies 9 a c]ta9 measure ! same effects may be obta9$ z ) high frequ5cies1 provid$ ! rate ( *ange is suffici5tly great4 ,s if a l[ frequ5cy curr5t is rais$ to a pot5tial (1 say1 #ge1jjj volts1 & ! high t5sion curr5t pass$ ?r\gh a s]ies ( high resi/ance lamp filam5ts1 ! importance ( ! r>efi$ gas surr\nd+ ! filam5t is cle>ly not$1 z w be se5 lat]2 or1 if a l[ frequ5cy curr5t ( sev]al ?\s& amp]es is pass$ ?r\gh a metal b>1 /rik+ ph5om5a ( imp$ance are obs]v$1 j z ) curr5ts ( high frequ5cies4 ,b x is1 ( c\rse1 evid5t t ) l[ frequ5cy curr5ts x is impossible to obta9 su* rates ( *ange p] unit ( "t z ) high frequ5cies1 h5ce ! effects produc$ by ! latt] are mu* m prom95t4 ,x is deem$ advisable to make ! prec$+ rem>ks1 inasmu* z _m m rec5tly describ$ effects h be5 unwitt+ly id5tifi$ ) high frequ5cies4 ,frequ5cy alone 9 reality does n mean any?+1 except :5 an undi/urb$ h>monic oscillation is consid]$4 ,9 ! bran* ,,iiib a simil> disposition to t 9 ,ib is illu/rat$1 ) ! diff]5ce t ! curr5ts dis*>g+ ?r\gh ! gap d d are us$ to induce curr5ts 9 ! second>y ,s ( a trans=m] ,t4 ,9 su* case ! second>y %\ld be provid$ ) an adju/able cond5s] = ! purpose ( tun+ x to ! prim>y4 ,,iib illu/rates a plan ( alt]nate curr5t high frequ5cy conv]sion :i* is mo/ frequ5tly us$ & :i* is f\nd to be mo/ conv5i5t4 ,?is plan has be5 dwelt ^u 9 detail on previ\s occasions & ne$ n be describ$ "h4 ,"s ( ^! results 7 obta9$ by ! use ( a high frequ5cy alt]nator4 ,a description ( su* ma*9es w be f\nd 9 my orig9al pap] be=e ! ,am]ican ,in/itute ( ,electrical ,eng9e]s1 & 9 p]iodicals ( t p]iod1 notably 9 ,,! ,,electrical ,,eng9e] ( ,m>* #ah1 #ahia4 ,i w n[ proce$ ) ! exp]im5ts4 ,,on ,,ph5om5a ,,produc$ ,,by ,,electro/atic ,,=ce4 ,! fir/ class ( effects ,i int5d to %[ y are effects produc$ by electro/atic =ce4 ,x is ! =ce :i* gov]ns ! ! motion ( ! atoms1 :i* causes !m to collide & develop ! life-su/a9+ en]gy ( heat & light1 & :i* causes !m to aggregate 9 an inf9ite v>iety ( ways1 accord+ to ,nature's fanciful designs1 & to =m all ^! wondr\s /ructures we p]ceive ar\nd u2 x is1 9 fact1 if our pres5t views be true1 ! mo/ important =ce = u to consid] 9 ,nature4 ,z ! t]m electro/atic might imply a /eady electric condition1 x %\ld be rem>k$1 t 9 ^! exp]im5ts ! =ce is n con/ant1 b v>ies at a rate :i* may be consid]$ mod]ate1 ab\t "o million times a second1 or !reab\ts4 ,?is enables me to produce _m effects :i* are n producible ) an unv>y+ =ce4 ,:5 two conduct+ bodies are insulat$ & electrifi$1 we say t an electro/atic =ce is act+ betwe5 !m4 ,?is =ce manife/s itself 9 attractions1 repulsions & /resses 9 ! bodies & space or m$ium )\t4 ,s great may be ! /ra9 ex]t$ 9 ! air1 or :atev] sep>ates ! two conduct+ bodies1 t x may break d[n1 & we obs]ve sp>ks or bundles ( light or /ream]s1 z !y are call$4 ,^! /ream]s =m abundantly :5 ! =ce ?r\gh ! air is rapidly v>y+4 ,i w illu/rate ?is action ( electro/atic =ce 9 a novel exp]im5t 9 :i* ,i w employ ! induction coil be=e ref]r$ to4 ,! coil is conta9$ 9 a tr\gh fill$ ) oil1 & plac$ "u ! table4 ,! two ends ( ! second>y wire pass ?r\gh ! two ?ick columns ( h>d rubb] :i* protrude to "s height above ! table4 ,x is necess>y to insulate ! ends or t]m9als ( ! second>y heavily ) h>d rubb]1 because ev5 dry wood is by f> too poor an insulator = ^! curr5ts ( enorm\s pot5tial diff]5ces4 ,on "o ( ! t]m9als ( ! coil1 ,i h plac$ a l>ge sph]e ( %eet brass1 :i* is connect$ to a l>g] insulat$ brass plate1 9 ord] to enable me to p]=m ! exp]im5ts "u conditions1 :i*1 z y w see1 are m suitable = ?is exp]im5t4 ,i n[ set ! coil to "w & approa* ! free t]m9al ) a metallic object held 9 my h&1 ?is simply to avoid burns4 ,z ,i approa* ! metallic object to a di/ance ( eight or t5 in*es1 a torr5t ( furi\s sp>ks breaks =? f ! end ( ! second>y wire1 :i* passes ?r\gh ! rubb] column4 ,! sp>ks cease :5 ! metal 9 my h& t\*es ! wire4 ,my arm is n[ trav]s$ by a p[]ful electric curr5t1 vibrat+ at ab\t ! rate ( "o million times a second4 ,all ar\nd me ! electro/atic =ce makes itself felt1 & ! air molecules & p>ticles ( du/ fly+ ab\t are act$ ^u & are hamm]+ viol5tly aga9/ my body4 ,s great is ?is agitation ( ! p>ticles1 t :5 ! lights are turn$ out y may see /reams ( feeble light appe> on "s p>ts ( my body4 ,:5 su* a /ream] breaks out on any "p ( ! body1 x produces a s5sation l ! prick+ ( a ne$le4 ,7 ! pot5tials suffici5tly high & ! frequ5cy ( ! vibration r l[1 ! sk9 w\ld probably be ruptur$ "u ! trem5d\s /ra91 & ! blood w\ld ru% out ) great =ce 9 ! =m ( f9e spray or jet s ?9 z to be invisible1 j z oil w :5 plac$ on ! positive t]m9al ( a ,holtz ma*9e4 ,! break+ ?r\gh ( ! sk9 ?\gh x may seem impossible at fir/1 w\ld p]haps occur1 by reason ( ! tissues "u ! sk9 be+ incomp>ably bett] conduct+4 ,?is1 at lea/1 appe>s plausible1 judg+ f "s obs]vations4 ,illu/ration3 ,,fig4 #afi4 ,i c make ^! /reams ( light visible to all1 by t\*+ ) ! metallic object "o ( ! t]m9als z be=e1 & approa*+ my free h& to ! brass sph]e1 :i* is connect$ to ! second t]m9al ( ! coil4 ,z ! h& is approa*$1 ! air betwe5 x & ! sph]e1 or 9 ! imm$iate neighborhood1 is m viol5tly agitat$1 & y see /reams ( light n[ break =? f my f+] tips & f ! :ole h& 7,fig4 #afi74 ,7 ,i to approa* ! h& clos]1 p[]ful sp>ks w\ld jump f ! brass sph]e to my h&1 :i* might be injuri\s4 ,! /ream]s (f] no p>ticul> inconv5i5ce1 except t 9 ! ends ( ! f+] tips a burn+ s5sation is felt4 ,!y %\ld n be conf\nd$ ) ^? produc$ by an influ5ce ma*9e1 because 9 _m respects !y behave diff]5tly4 ,i h atta*$ ! brass sph]e & plate to "o ( ! t]m9als 9 ord] to prev5t ! =mation ( visible /ream]s on t t]m9al1 also 9 ord] to prev5t sp>ks f jump+ at a consid]able di/ance4 ,besides1 ! atta*m5t is favorable = ! work+ ( ! coil4 ,! /reams ( light :i* y h obs]v$ issu+ f my h& are due to a pot5tial ( ab\t #bjj1jjj volts1 alt]nat+ 9 r irregul> int]vals1 sometimes l a million times a second4 ,a vibration ( ! same amplitude1 b f\r times z fa/1 to ma9ta9 :i* ov] #c1jjj1jjj volts w\ld be requir$1 w\ld be m ?an suffici5t to envelop my body 9 a complete %eet ( flame4 ,b ?is flame w\ld n burn me up2 q contr>ily1 ! probability is t ,i w\ld n be injur$ 9 ! lea/4 ,yet a hundr$? "p ( t en]gy1 o!rwise direct$1 w\ld be amply suffici5t to kill a p]son4 ,! am\nt ( en]gy :i* may ?us be pass$ into ! body ( a p]son dep5ds on ! frequ5cy & pot5tial ( ! curr5ts1 & by mak+ bo? ( ^! v great1 a va/ am\nt ( en]gy may be pass$ into ! body )\t caus+ any discom=t1 except p]haps1 9 ! arm1 :i* is trav]s$ by a true conduction curr5t4 ,! reason :y no pa9 9 ! body is felt1 & no injuri\s effect not$1 is t ev]y:]e1 if a curr5t be imag9$ to fl[ ?r\gh ! body1 ! direction ( its fl[ w\ld be at "r angles to ! surface2 h5ce ! body ( ! exp]im5t] (f]s an enorm\s section to ! curr5t1 & ! d5sity is v small1 ) ! exception ( ! arm1 p]haps1 :]e ! d5sity may be consid]able4 ,b if only a small fraction ( t en]gy w\ld be appli$ 9 su* a way t a curr5t w\ld trav]se ! body 9 ! same mann] z a l[ frequ5cy curr5t1 a %ock w\ld be receiv$ :i* might be fatal4 ,a direct or l[ frequ5cy alt]nat+ curr5t is fatal1 ,i ?9k1 pr9cipally because its di/ribution ?r\gh ! body is n uni=m1 z x mu/ divide itself 9 m9ute /reamlets ( great d5sity1 :]eby "s organs are vitally injur$4 ,t su* a process occurs ,i h n ! lea/ d\bt1 ?\gh no evid5ce might app>5tly exi/1 or be f\nd ^u exam9ation4 ,! sure/ to injure & de/roy life1 is a cont9u\s curr5t1 b ! mo/ pa9ful is an alt]nat+ curr5t ( v l[ frequ5cy4 ,! expression ( ^! views1 :i* are ! result ( long cont9u$ exp]im5t & obs]vation1 bo? ) /eady & v>y+ curr5ts1 is elicit$ by ! int]e/ :i* is at pres5t tak5 9 ?is subject1 & by ! manife/ly errone\s ideas :i* are daily prop\nd$ 9 j\rnals on ?is subject4 ,i may illu/rate an effect ( ! electro/atic =ce by ano!r /rik+ exp]im5t1 b be=e1 ,i mu/ call y\r att5tion to "o or two facts4 ,i h said be=e1 t :5 ! m$ium betwe5 two oppositely electrifi$ bodies is /ra9$ beyond a c]ta9 limit x gives way &1 /at$ 9 popul> language1 ! opposite electric *>ges unite & neutralize ea* o!r4 ,?is break+ d[n ( ! m$ium occurs pr9cipally :5 ! =ce act+ betwe5 ! bodies is /eady1 or v>ies at a mod]ate rate4 ,7 ! v>iation suffici5tly rapid1 su* a de/ructive break w\ld n occur1 no matt] h[ great ! =ce1 = all ! en]gy w\ld be sp5t 9 radiation1 convection & me*anical & *emical action4 ,?us ! sp>k l5g?1 or greate/ di/ance :i* a sp>k w jump betwe5 ! electrifi$ bodies is ! small]1 ! great] ! v>iation or "t rate ( *ange4 ,b ?is rule may be tak5 to be true only 9 a g5]al way1 :5 comp>+ rates :i* are widely diff]5t4 ,illu/ration3 ,,fig4 #agj;a4 ,illu/ration3 ,,fig4 #agj;b4 ,i w %[ y by an exp]im5t ! diff]5ce 9 ! effect produc$ by a rapidly v>y+ & a /eady or mod]ately v>y+ =ce4 ,i h "h two l>ge circul> brass plates p p 7,fig4 #agj;a & ,fig4 #agj;b71 support$ on movable insulat+ /&s on ! table1 connect$ to ! ends ( ! second>y ( a coil simil> to ! "o us$ be=e4 ,i place ! plates t5 or twelve in*es ap>t & set ! coil to "w4 ,y see ! :ole space betwe5 ! plates1 ne>ly two cubic feet1 fill$ ) uni=m light1 ,fig4 #agj;a4 ,?is light is due to ! /ream]s y h se5 9 ! fir/ exp]im5t1 :i* are n[ mu* m int5se4 ,i h already po9t$ out ! importance ( ^! /ream]s 9 comm]cial app>atus & _! /ill great] importance 9 "s purely sci5tific inve/igations4 ,(t5 !y are too weak to be visible1 b !y always exi/1 consum+ en]gy & modify+ ! action ( ! app>atus4 ,:5 int5se1 z !y are at pres5t1 !y produce ozone 9 great quantity1 & also1 z ,pr(essor ,crookes has po9t$ out1 nitr\s acid4 ,s quick is ! *emical action t if a coil1 su* z ?is "o1 is work$ = a v long "t x w make ! atmosph]e ( a small room unbe>able1 = ! eyes & ?roat are attack$4 ,b :5 mod]ately produc$1 ! /ream]s refre% ! atmosph]e wond]fully1 l a ?und]-/orm1 & ex]cises unque/ionably a b5eficial effect4 ,9 ?is exp]im5t ! =ce act+ betwe5 ! plates *anges 9 int5sity & direction at a v rapid rate4 ,i w n[ make ! rate ( *ange p] unit "t mu* small]4 ,?is ,i effect by r5d]+ ! dis*>ges ?r\gh ! prim>y ( ! induction coil less frequ5t1 & also by dim9i%+ ! rapidity ( ! vibration 9 ! second>y4 ,! =m] result is conv5i5tly secur$ by l[]+ ! ,e4 ,m4 ,f4 ov] ! air gap 9 ! prim>y circuit1 ! latt] by approa*+ ! two brass plates to a di/ance ( ab\t ?ree or f\r in*es4 ,:5 ! coil is set to "w1 y see no /ream]s or light betwe5 ! plates1 yet ! m$ium betwe5 !m is "u a trem5d\s /ra94 ,i /ill fur!r augm5t ! /ra9 by rais+ ! ,e4 ,m4 ,f4 9 ! prim>y circuit1 & soon y see ! air give way & ! hall is illum9at$ by a %[] ( brilliant & noisy sp>ks1 ,fig4 #agj;b4 ,^! sp>ks c\ld be produc$ also ) unv>y+ =ce2 !y h be5 = _m ye>s a famili> ph5om5on1 ?\gh !y 7 usually obta9$ f an entirely diff]5t app>atus4 ,9 describ+ ^! two ph5om5a s radically diff]5t 9 appe>ance1 ,i h advis$ly spok5 ( a =ce act+ betwe5 ! plates4 ,x w\ld be 9 accordance ) accept$ views to say1 t !re 0 an alt]nat+ ,e4 ,m4 ,f1 act+ betwe5 ! plates4 ,?is t]m is q prop] & applicable 9 all cases :]e !re is evid5ce ( at lea/ a possibility ( an ess5tial int]-dep5d5ce ( ! electric /ate ( ! plates1 or electric action 9 _! neighborhood4 ,b if ! plates 7 remov$ to an inf9ite di/ance1 or if at a f9ite di/ance1 !re is no probability or necessity :atev] = su* dep5d5ce4 ,i pref] to use ! t]m electro/atic =ce1 & to say t su* a =ce is act+ ar\nd ea* plate or electrifi$ insulat$ body 9 g5]al4 ,!re is an inconv5i5ce 9 us+ ?is expression z ! t]m incid5tally means a /eady electric condition2 b a prop] nom5clature w ev5tually settle ?is difficulty4 ,i n[ return to ! exp]im5t to :i* ,i h already allud$1 & ) :i* ,i desire to illu/rate a /rik+ effect produc$ by a rapidly v>y+ electro/atic =ce4 ,i atta* to ! end ( ! wire1 l 7,fig4 #aga71 :i* is 9 connection ) "o ( ! t]m9als ( ! second>y ( ! induction coil1 an exhau/$ bulb b4 ,?is bulb conta9s a ?9 c>bon filam5t f1 :i* is fa/5$ to a plat9um wire w1 seal$ 9 ! glass & lead+ outside ( ! bulb1 :]e x connects to ! wire l4 ,! bulb may be exhau/$ to any degree atta9able ) ord9>y app>atus4 ,j a mom5t be=e1 y h witness$ ! break+ d[n ( ! air betwe5 ! *>g$ brass plates4 ,y "k t a plate ( glass1 or any o!r insulat+ mat]ial1 w\ld break d[n 9 l mann]4 ,_h ,i !re=e a metallic coat+ atta*$ to ! outside ( ! bulb1 or plac$ ne> ! same1 & 7 ?is coat+ connect$ to ! o!r t]m9al ( ! coil1 y w\ld be prep>$ to see ! glass give way if ! /ra9 7 suffici5tly increas$4 ,ev5 7 ! coat+ n connect$ to ! o!r t]m9al1 b to an insulat$ plate1 /ill1 if y h foll[$ rec5t developm5ts1 y w\ld naturally expect a rupture ( ! glass4 ,illu/ration3 ,,fig4 #aga4 ,illu/ration3 ,,fig4 #agb;a4 ,illu/ration3 ,,fig4 #agb;b4 ,b x w c]ta9ly surprise y to note t "u ! action ( ! v>y+ electro/atic =ce1 ! glass gives way :5 all o!r bodies are remov$ f ! bulb4 ,9 fact1 all ! surr\nd+ bodies we p]ceive might be remov$ to an inf9ite di/ance )\t affect+ ! result 9 ! slighte/4 ,:5 ! coil is set to "w1 ! glass is inv>iably brok5 ?r\gh at ! seal1 or o!r n>r[ *annel1 & ! vacuum is quickly impair$4 ,su* a damag+ break w\ld n occur ) a /eady =ce1 ev5 if ! same 7 _m times great]4 ,! break is due to ! agitation ( ! molecules ( ! gas )9 ! bulb1 & outside ( ! same4 ,?is agitation1 :i* is g5]ally mo/ viol5t 9 ! n>r[ po9t$ *annel ne> ! seal1 causes a heat+ & rupture ( ! glass4 ,?is rupture1 w\ld1 h[ev]1 n occur1 n ev5 ) a v>y+ =ce1 if ! m$ium fill+ ! inside ( ! bulb1 & t surr\nd+ x1 7 p]fectly homog5e\s4 ,! break occurs mu* quick] if ! top ( ! bulb is drawn out into a f9e fibre4 ,9 bulbs us$ ) ^! coils su* n>r[1 po9t$ *annels mu/ !re=e be avoid$4 ,:5 a conduct+ body is imm]s$ 9 air1 or simil> insulat+ m$ium1 consi/+ (1 or conta9+1 small freely movable p>ticles capable ( be+ electrifi$1 & :5 ! electrification ( ! body is made to und]go a v rapid *ange--:i* is equival5t to say+ t ! electro/atic =ce act+ ar\nd ! body is v>y+ 9 int5sity1--! small p>ticles are attract$ & repell$1 & _! viol5t impacts aga9/ ! body may cause a me*anical motion ( ! latt]4 ,ph5om5a ( ?is k9d are notewor?y1 inasmu* z !y h n be5 obs]v$ be=e ) app>atus su* z has be5 commonly 9 use4 ,if a v light conduct+ sph]e be susp5d$ on an exce$+ly f9e wire1 & *>g$ to a /eady pot5tial1 h[ev] high1 ! sph]e w rema9 at re/4 ,ev5 if ! pot5tial w\ld be rapidly v>y+1 provid$ t ! small p>ticles ( matt]1 molecules or atoms1 are ev5ly di/ribut$1 no motion ( ! sph]e %\ld result4 ,b if "o side ( ! conduct+ sph]e is cov]$ ) a ?ick insulat+ lay]1 ! impacts ( ! p>ticles w cause ! sph]e to move ab\t1 g5]ally 9 irregul> curves1 ,fig4 #agb;a4 ,9 l mann]1 z ,i h %[n on a previ\s occasion1 a fan ( %eet metal1 ,fig4 #agb;b1 cov]$ p>tially ) insulat+ mat]ial z indicat$1 & plac$ ^u ! t]m9al ( ! coil s z to turn freely on x1 is spun ar\nd4 ,all ^! ph5om5a y h witness$ & o!rs :i* w be %[n lat]1 are due to ! pres5ce ( a m$ium l air1 & w\ld n occur 9 a cont9u\s m$ium4 ,! action ( ! air may be illu/rat$ /ill bett] by ! foll[+ exp]im5t4 ,i take a glass tube t1 ,fig4 #agc1 ( ab\t an in* 9 diamet]1 :i* has a plat9um wire w seal$ 9 ! l[] end1 & to :i* is atta*$ a ?9 lamp filam5t f4 ,i connect ! wire ) ! t]m9al ( ! coil & set ! coil to "w4 ,! plat9um wire is n[ electrifi$ positively & negatively 9 rapid succession & ! wire & air inside ( ! tube is rapidly heat$ by ! impacts ( ! p>ticles1 :i* may be s viol5t z to r5d] ! filam5t inc&esc5t4 ,b if ,i p\r oil 9 ! tube1 j z soon z ! wire is cov]$ ) ! oil1 all action app>5tly ceases & !re is no m>k$ evid5ce ( heat+4 ,! reason ( ?is is t ! oil is a practically cont9u\s m$ium4 ,! displacem5ts 9 su* a cont9u\s m$ium are1 ) ^! frequ5cies1 to all appe>ance incomp>ably small] ?an 9 air1 h5ce ! "w p]=m$ 9 su* a m$ium is insignificant4 ,b oil w\ld behave v diff]5tly ) frequ5cies _m times z great1 = ev5 ?\gh ! displacem5ts be small1 if ! frequ5cy 7 mu* great]1 consid]able "w might be p]=m$ 9 ! oil4 ,illu/ration3 ,,fig4 #agc4 ,illu/ration3 ,,fig4 #agd4 ,! electro/atic attractions & repulsions betwe5 bodies ( measurable dim5sions are1 ( all ! manife/ations ( ?is =ce1 ! fir/ s-call$ electrical ph5om5a not$4 ,b ?\gh !y h be5 kn[n to u = _m c5turies1 ! precise nature ( ! me*anism conc]n$ 9 ^! actions is /ill unkn[n to u1 & has n be5 ev5 q satisfactorily expla9$4 ,:at k9d ( me*anism mu/ t be8 ,we _c help wond]+ :5 we obs]ve two magnets attract+ & repell+ ea* o!r ) a =ce ( hundr$s ( p\nds ) app>5tly no?+ betwe5 !m4 ,we h 9 our comm]cial dynamos magnets capable ( su/a9+ 9 mid-air tons ( weight4 ,b :at are ev5 ^! =ces act+ betwe5 magnets :5 comp>$ ) ! trem5d\s attractions & repulsions produc$ by electro/atic =ce1 to :i* !re is app>5tly no limit z to int5sity4 ,9 lightn+ dis*>ges bodies are (t5 *>g$ to s high a pot5tial t !y are ?r[n away ) inconceivable =ce & torn asund] or %att]$ into fragm5ts4 ,/ill ev5 su* effects _c comp>e ) ! attractions & repulsions :i* exi/ betwe5 *>g$ molecules or atoms1 & :i* are suffici5t to project !m ) spe$s ( _m kilometres a second1 s t "u _! viol5t impact bodies are r5d]$ highly inc&esc5t & are volatiliz$4 ,x is ( special int]e/ = ! ?9k] :o inquires into ! nature ( ^! =ces to note t :]eas ! actions betwe5 individual molecules or atoms occur seem+ly "u any conditions1 ! attractions & repulsions ( bodies ( measurable dim5sions imply a m$ium possess+ insulat+ prop]ties4 ,s1 if air1 ei!r by be+ r>efi$ or heat$1 is r5d]$ m or less conduct+1 ^! actions betwe5 two electrifi$ bodies practically cease1 :ile ! actions betwe5 ! individual atoms cont9ue to manife/ !mselves4 ,an exp]im5t may s]ve z an illu/ration & z a means ( br++ out o!r features ( int]e/4 ,"s "t ago ,i %[$ t a lamp filam5t or wire m\nt$ 9 a bulb & connect$ to "o ( ! t]m9als ( a high t5sion second>y coil is set sp9n+1 ! top ( ! filam5t g5]ally describ+ a circle4 ,?is vibration 0 v en]getic :5 ! air 9 ! bulb 0 at ord9>y pressure & became less en]getic :5 ! air 9 ! bulb 0 /rongly compress$4 ,x ceas$ altoge!r :5 ! air 0 exhau/$ s z to become comp>atively good conduct+4 ,i f\nd at t "t t no vibration took place :5 ! bulb 0 v highly exhau/$4 ,b ,i conjectur$ t ! vibration :i* ,i ascrib$ to ! electro/atic action betwe5 ! walls ( ! bulb & ! filam5t %\ld take place also 9 a highly exhau/$ bulb4 ,to te/ ?is "u conditions :i* 7 m favorable1 a bulb l ! "o 9 ,fig4 #agd1 0 con/ruct$4 ,x compris$ a globe b1 9 ! neck ( :i* 0 seal$ a plat9um wire w c>ry+ a ?9 lamp filam5t f4 ,9 ! l[] "p ( ! globe a tube t 0 seal$ s z to surr\nd ! filam5t4 ,! exhau/ion 0 c>ri$ z f> z x 0 practicable ) ! app>atus employ$4 ,?is bulb v]ifi$ my expectation1 = ! filam5t 0 set sp9n+ :5 ! curr5t 0 turn$ on1 & became inc&esc5t4 ,x also %[$ ano!r int]e/+ feature1 be>+ ^u ! prec$+ rem>ks1 namely1 :5 ! filam5t _h be5 kept inc&esc5t "s "t1 ! n>r[ tube & ! space inside 7 br\ght to an elevat$ temp]ature1 & z ! gas 9 ! tube !n became conduct+1 ! electro/atic attraction betwe5 ! glass & ! filam5t became v weak or ceas$1 & ! filam5t came to re/4 ,:5 x came to re/ x w\ld gl[ f> m int5sely4 ,?is 0 probably due to its assum+ ! position 9 ! c5tre ( ! tube :]e ! molecul> bomb>dm5t 0 mo/ int5se1 & also p>tly to ! fact t ! individual impacts 7 m viol5t & t no "p ( ! suppli$ en]gy 0 conv]t$ into me*anical movem5t4 ,s9ce1 9 accordance ) accept$ views1 9 ?is exp]im5t ! inc&esc5ce mu/ be attribut$ to ! impacts ( ! p>ticles1 molecules or atoms 9 ! heat$ space1 ^! p>ticles mu/ !re=e1 9 ord] to expla9 su* action1 be assum$ to behave z indep5d5t c>ri]s ( electric *>ges imm]s$ 9 an insulat+ m$ium2 yet !re is no attractive =ce betwe5 ! glass tube & ! filam5t because ! space 9 ! tube is1 z a :ole1 conduct+4 ,x is ( "s int]e/ to obs]ve 9 ?is connection t :]eas ! attraction betwe5 two electrifi$ bodies may cease ow+ to ! impair+ ( ! insulat+ p[] ( ! m$ium 9 :i* !y are imm]s$1 ! repulsion betwe5 ! bodies may /ill be obs]v$4 ,?is may be expla9$ 9 a plausible way4 ,:5 ! bodies are plac$ at "s di/ance 9 a poorly conduct+ m$ium1 su* z slightly w>m$ or r>efi$ air1 & are sudd5ly electrifi$1 opposite electric *>ges be+ imp>t$ to !m1 ^! *>ges equalize m or less by leakage ?r\gh ! air4 ,b if ! bodies are simil>ly electrifi$1 !re is less opportunity af=d$ = su* dissipation1 h5ce ! repulsion obs]v$ 9 su* case is great] ?an ! attraction4 ,repulsive actions 9 a gase\s m$ium are h[ev]1 z ,pr(4 ,crookes has %[n1 enhanc$ by molecul> bomb>dm5t4 ,,on ,,curr5t ,,or ,,dynamic ,,electricity ,,ph5om5a4 ,s f>1 ,i h consid]$ pr9cipally effects produc$ by a v>y+ electro/atic =ce 9 an insulat+ m$ium1 su* z air4 ,:5 su* a =ce is act+ ^u a conduct+ body ( measurable dim5sions1 x causes )9 ! same1 or on its surface1 displacem5ts ( ! electricity & gives rise to electric curr5ts1 & ^! produce ano!r k9d ( ph5om5a1 "s ( :i* ,i %all pres5tly endeavor to illu/rate4 ,9 pres5t+ ?is second class ( electrical effects1 ,i w avail myself pr9cipally ( su* z are producible )\t any return circuit1 hop+ to int]e/ y ! m by pres5t+ ^! ph5om5a 9 a m or less novel aspect4 ,x has be5 a long "t cu/om>y1 ow+ to ! limit$ exp]i5ce ) vibratory curr5ts1 to consid] an electric curr5t z some?+ circulat+ 9 a clos$ conduct+ pa?4 ,x 0 a/oni%+ at fir/ to realize t a curr5t may fl[ ?r\gh ! conduct+ pa? ev5 if ! latt] be int]rupt$1 & x 0 /ill m surpris+ to le>n1 t sometimes x may be ev5 easi] to make a curr5t fl[ "u su* conditions ?an ?r\gh a clos$ pa?4 ,b t old idea is gradually disappe>+1 ev5 among practical m51 & w soon be entirely =gott54 ,illu/ration3 ,,fig4 #age4 ,if ,i connect an insulat$ metal plate ,p1 ,fig4 #age1 to "o ( ! t]m9als ,t ( ! induction coil by means ( a wire1 ?\gh ?is plate be v well insulat$1 a curr5t passes ?r\gh ! wire :5 ! coil is set to "w4 ,fir/ ,i wi% to give y evid5ce t !re is a curr5t pass+ ?r\gh ! connect+ wire4 ,an obvi\s way ( demon/rat+ ?is is to ins]t betwe5 ! t]m9al ( ! coil & ! insulat$ plate a v ?9 plat9um or g]man silv] wire w & br+ ! latt] to inc&esc5ce or fusion by ! curr5t4 ,?is requires a r l>ge plate or else curr5t impulses ( v high pot5tial & frequ5cy4 ,ano!r way is to take a coil ,c1 ,fig4 #age1 conta9+ _m turns ( ?9 insulat$ wire & to ins]t ! same 9 ! pa? ( ! curr5t to ! plate4 ,:5 ,i connect "o ( ! ends ( ! coil to ! wire lead+ to ano!r insulat$ plate ,p#a1 & its o!r end to ! t]m9al ,t#a ( ! induction coil1 & set ! latt] to "w1 a curr5t passes ?r\gh ! ins]t$ coil ,c & ! exi/5ce ( ! curr5t may be made manife/ 9 v>i\s ways4 ,= in/ance1 ,i ins]t an iron core i )9 ! coil4 ,! curr5t be+ "o ( v high frequ5cy1 w1 if x be ( "s /r5g?1 soon br+ ! iron core to a noticeably high] temp]ature1 z ! hy/]esis & curr5t losses are great ) su* high frequ5cies4 ,"o might take a core ( "s size1 lam9at$ or n1 x w\ld matt] little2 b ord9>y iron wire #a_/af? or #a_/h? ( an in* ?ick is suitable = ! purpose4 ,:ile ! induction coil is work+1 a curr5t trav]ses ! ins]t$ coil & only a few mom5ts are suffici5t to br+ ! iron wire i to an elevat$ temp]ature suffici5t to s(t5 ! seal+-wax s1 & cause a pap] wa%] p fa/5$ by x to ! iron wire to fall (f4 ,b ) ! app>atus su* z ,i h "h1 o!r1 mu* m int]e/+1 demon/rations ( ?is k9d c be made4 ,i h a second>y ,s1 ,fig #agf1 ( co>se wire1 w\nd ^u a coil simil> to ! fir/4 ,9 ! prec$+ exp]im5t ! curr5t ?r\gh ! coil ,c1 ,fig4 #age1 0 v small1 b !re be+ _m turns a /rong heat+ effect 01 nev]!less1 produc$ 9 ! iron wire4 ,_h ,i pass$ t curr5t ?r\gh a conductor 9 ord] to %[ ! heat+ ( ! latt]1 ! curr5t might h be5 too small to produce ! effect desir$4 ,b ) ?is coil provid$ ) a second>y w9d+1 ,i c n[ trans=m ! feeble curr5t ( high t5sion :i* passes ?r\gh ! prim>y ,p into a /rong second>y curr5t ( l[ t5sion1 & ?is curr5t w q c]ta9ly d :at ,i expect4 ,9 a small glass tube 7t1 ,fig4 #agf71 ,i h enclos$ a coil$ plat9um wire1 w1 ?is m]ely 9 ord] to protect ! wire4 ,on ea* end ( ! glass tube is seal$ a t]m9al ( /\t wire to :i* "o ( ! ends ( ! plat9um wire w1 is connect$4 ,i jo9 ! t]m9als ( ! second>y coil to ^! t]m9als & ins]t ! prim>y p1 betwe5 ! insulat$ plate ,p#a1 & ! t]m9al ,t#a1 ( ! induction coil z be=e4 ,! latt] be+ set to "w1 in/antly ! plat9um wire w is r5d]$ inc&esc5t & c be fus$1 ev5 if x be v ?ick4 ,illu/ration3 ,,fig4 #agf4 ,in/ead ( ! plat9um wire ,i n[ take an ord9>y #ej-volt #af ,c4 ,p4 lamp4 ,:5 ,i set ! induction coil 9 op]ation ! lamp filam5t is br\ght to high inc&esc5ce4 ,x is1 h[ev]1 n necess>y to use ! insulat$ plate1 = ! lamp 7l1 ,fig4 #agg7 is r5d]$ inc&esc5t ev5 if ! plate ,p#a be disconnect$4 ,! second>y may also be connect$ to ! prim>y z indicat$ by ! dott$ l9e 9 ,fig4 #agg1 to d away m or less ) ! electro/atic induction or to modify ! action o!rwise4 ,illu/ration3 ,,fig4 #agg4 ,i may "h call att5tion to a numb] ( int]e/+ obs]vations ) ! lamp4 ,fir/1 ,i disconnect "o ( ! t]m9als ( ! lamp f ! second>y ,s4 ,:5 ! induction coil plays1 a gl[ is not$ :i* fills ! :ole bulb4 ,?is gl[ is due to electro/atic induction4 ,x increases :5 ! bulb is grasp$ ) ! h&1 & ! capacity ( ! exp]im5t]'s body ?us add$ to ! second>y circuit4 ,! second>y1 9 effect1 is equival5t to a metallic coat+1 :i* w\ld be plac$ ne> ! prim>y4 ,if ! second>y1 or its equival5t1 ! coat+1 7 plac$ symmetrically to ! prim>y1 ! electro/atic induction w\ld be nil "u ord9>y conditions1 t is1 :5 a prim>y return circuit is us$1 z bo? halves w\ld neutralize ea* o!r4 ,! second>y is 9 fact plac$ symmetrically to ! prim>y1 b ! action ( bo? halves ( ! latt]1 :5 only "o ( its ends is connect$ to ! induction coil1 is n exactly equal2 h5ce electro/atic induction takes place1 & h5ce ! gl[ 9 ! bulb4 ,i c ne>ly equalize ! action ( bo? halves ( ! prim>y by connect+ ! o!r1 free end ( ! same to ! insulat$ plate1 z 9 ! prec$+ exp]im5t4 ,:5 ! plate is connect$1 ! gl[ disappe>s4 ,) a small] plate x w\ld n entirely disappe> & !n x w\ld contribute to ! brightness ( ! filam5t :5 ! second>y is clos$1 by w>m+ ! air 9 ! bulb4 ,illu/ration3 ,,fig4 #agh;a4 ,illu/ration3 ,,fig4 #agh;b4 ,illu/ration3 ,,fig4 #agi;a4 ,illu/ration3 ,,fig4 #agi;b4 ,to demon/rate ano!r int]e/+ feature1 ,i h adju/$ ! coils us$ 9 a c]ta9 way4 ,i fir/ connect bo? ! t]m9als ( ! lamp to ! second>y1 "o end ( ! prim>y be+ connect$ to ! t]m9al ,t#a ( ! induction coil & ! o!r to ! insulat$ plate ,p#a z be=e4 ,:5 ! curr5t is turn$ on1 ! lamp gl[s brightly1 z %[n 9 ,fig4 #agh;b1 9 :i* ,c is a f9e wire coil & ,s a co>se wire second>y w\nd ^u x4 ,if ! insulat$ plate ,p#a is disconnect$1 leav+ "o ( ! ends a ( ! prim>y insulat$1 ! filam5t becomes d>k or g5]ally x dim9i%es 9 brightness 7,fig4 #agh;a74 ,connect+ aga9 ! plate ,p#a & rais+ ! frequ5cy ( ! curr5t1 ,i make ! filam5t q d>k or b>ely r$ 7,fig4 #agi;b74 ,once m ,i w disconnect ! plate4 ,"o w ( c\rse inf] t :5 ! plate is disconnect$1 ! curr5t ?r\gh ! prim>y w be weak5$1 t !re=e ! ,e4 ,m4 ,f4 w fall 9 ! second>y ,s1 & t ! brightness ( ! lamp w dim9i%4 ,?is might be ! case & ! result c be secur$ by an easy adju/m5t ( ! coils2 also by v>y+ ! frequ5cy & pot5tial ( ! curr5ts4 ,b x is p]haps ( great] int]e/ to note1 t ! lamp increases 9 brightness :5 ! plate is disconnect$ 7,fig4 #agi;a74 ,9 ?is case all ! en]gy ! prim>y receives is n[ sunk into x1 l ! *>ge ( a batt]y 9 an ocean cable1 b mo/ ( t en]gy is recov]$ ?r\gh ! second>y & us$ to light ! lamp4 ,! curr5t trav]s+ ! prim>y is /ronge/ at ! end b :i* is connect$ to ! t]m9al ,t#a ( ! induction coil1 & dim9i%es 9 /r5g? t[>ds ! remote end a4 ,b ! dynamic inductive effect ex]t$ ^u ! second>y ,s is n[ great] ?an be=e1 :5 ! susp5d$ plate 0 connect$ to ! prim>y4 ,^! results might h be5 produc$ by a numb] ( causes4 ,= in/ance1 ! plate ,p#a be+ connect$1 ! reaction f ! coil ,c may be su* z to dim9i% ! pot5tial at ! t]m9al ,t#a ( ! induction coil1 & !re=e weak5 ! curr5t ?r\gh ! prim>y ( ! coil ,c4 ,or ! disconnect+ ( ! plate may dim9i% ! capacity effect ) relation to ! prim>y ( ! latt] coil to su* an ext5t t ! curr5t ?r\gh x is dim9i%$1 ?\gh ! pot5tial at ! t]m9al ,t#a ( ! induction coil may be ! same or ev5 high]4 ,or ! result might h be5 produc$ by ! *ange ( phase ( ! prim>y & second>y curr5ts & consequ5t reaction4 ,b ! *ief det]m9+ factor is ! relation ( ! self-induction & capacity ( coil ,c & plate ,p#a & ! frequ5cy ( ! curr5ts4 ,! great] brightness ( ! filam5t 9 ,fig4 #agi;a1 is1 h[ev]1 9 "p due to ! heat+ ( ! r>efi$ gas 9 ! lamp by electro/atic induction1 :i*1 z be=e rem>k$1 is great] :5 ! susp5d$ plate is disconnect$4 ,/ill ano!r feature ( "s int]e/ ,i may "h br+ to y\r att5tion4 ,:5 ! insulat$ plate is disconnect$ & ! second>y ( ! coil op5$1 by approa*+ a small object to ! second>y1 b v small sp>ks c be drawn f x1 %[+ t ! electro/atic induction is small 9 ?is case4 ,b ^u ! second>y be+ clos$ ^u itself or ?r\gh ! lamp1 ! filam5t gl[+ brightly1 /rong sp>ks are obta9$ f ! second>y4 ,! electro/atic induction is n[ mu* great]1 because ! clos$ second>y det]m9es a great] fl[ ( curr5t ?r\gh ! prim>y & pr9cipally ?r\gh t half ( x :i* is connect$ to ! induction coil4 ,if n[ ! bulb be grasp$ ) ! h&1 ! capacity ( ! second>y ) ref]5ce to ! prim>y is augm5t$ by ! exp]im5t]'s body & ! lum9osity ( ! filam5t is increas$1 ! inc&esc5ce n[ be+ due p>tly to ! fl[ ( curr5t ?r\gh ! filam5t & p>tly to ! molecul> bomb>dm5t ( ! r>efi$ gas 9 ! bulb4 ,! prec$+ exp]im5ts w h prep>$ "o = ! next foll[+ results ( int]e/1 obta9$ 9 ! c\rse ( ^! inve/igations4 ,s9ce ,i c pass a curr5t ?r\gh an insulat$ wire m]ely by connect+ "o ( its ends to ! s\rce ( electrical en]gy1 s9ce ,i c induce by x ano!r curr5t1 magnetize an iron core1 &1 9 %ort1 p]=m all op]ations z ?\gh a return circuit 7 us$1 cle>ly ,i c also drive a motor by ! aid ( only "o wire4 ,on a =m] occasion ,i h describ$ a simple =m ( motor compris+ a s+le excit+ coil1 an iron core & disc4 ,fig4 #ahj illu/rates a modifi$ way ( op]at+ su* an alt]nate curr5t motor by curr5ts induc$ 9 a trans=m] connect$ to "o lead1 & sev]al o!r arrangem5ts ( circuits = op]at+ a c]ta9 class ( alt]nat+ motors f\nd$ on ! action ( curr5ts ( diff]+ phase4 ,9 view ( ! pres5t /ate ( ! art x is ?\ght suffici5t to describe ^! arrangem5ts 9 a few words only4 ,! diagram1 ,fig4 #ahj ,,ii41 %[s a prim>y coil ,p1 connect$ ) "o ( its ends to ! l9e ,l lead+ f a high t5sion trans=m] t]m9al ,t#a4 ,9 inductive relation to ?is prim>y ,p is a second>y ,s ( co>se wire 9 ! circuit ( :i* is a coil c4 ,! curr5ts induc$ 9 ! second>y en]gize ! iron core i1 :i* is pref]ably1 b n necess>ily1 subdivid$1 & set ! metal disc d 9 rotation4 ,su* a motor ,m#b z diagramatically %[n 9 ,fig4 #ahj ,,ii41 has be5 call$ a magnetic lag motor1 b ?is expression may be object$ to by ^? :o attribute ! rotation ( ! disc to eddy curr5ts circulat+ 9 m9ute pa?s :5 ! core i is f9ally subdivid$4 ,9 ord] to op]ate su* a motor effectively on ! plan indicat$1 ! frequ5cies %\ld n be too high1 n m ?an f\r or five ?\s&1 ?\gh ! rotation is produc$ ev5 ) t5 ?\s& p] second1 or m4 ,9 ,fig4 #ahj ,i41 a motor ,m#a hav+ two en]giz+ circuits1 ,a & ,b1 is diagrammatically indicat$4 ,! circuit ,a is connect$ to ! l9e ,l & 9 s]ies ) x is a prim>y ,p1 :i* may h its free end connect$ to an insulat$ plate ,p#a1 su* connection be+ indicat$ by ! dott$ l9es4 ,! o!r motor circuit ,b is connect$ to ! second>y ,s :i* is 9 inductive relation to ! prim>y ,p4 ,:5 ! trans=m] t]m9al ,t#a is alt]nately electrifi$1 curr5ts trav]se ! op5 l9e ,l & also circuit ,a & prim>y ,p4 ,! curr5ts ?r\gh ! latt] induce second>y curr5ts 9 ! circuit ,s1 :i* pass ?r\gh ! en]giz+ coil ,b ( ! motor4 ,! curr5ts ?r\gh ! second>y ,s & ^? ?r\gh ! prim>y ,p diff] 9 phase #ij degrees1 or ne>ly s1 & are capable ( rotat+ an armature plac$ 9 inductive relation to ! circuits ,a & ,b4 ,9 ,fig4 #ahj ,,iii41 a simil> motor ,m#c ) two en]giz+ circuits ,a#a & ,b#a is illu/rat$4 ,a prim>y ,p1 connect$ ) "o ( its ends to ! l9e ,l has a second>y ,s1 :i* is pref]ably w\nd = a tol]ably high ,e4 ,m4 ,f41 & to :i* ! two en]giz+ circuits ( ! motor are connect$1 "o directly to ! ends ( ! second>y & ! o!r ?r\gh a cond5s] ,c1 by ! action ( :i* ! curr5ts trav]s+ ! circuit ,a#a & ,b#a are made to diff] 9 phase4 ,illu/ration3 ,,fig4 #ahj4 ,illu/ration3 ,,fig4 #aha4 ,illu/ration3 ,,fig4 #ahb4 ,9 ,fig4 #ahj ,,iv41 /ill ano!r arrangem5t is %[n4 ,9 ?is case two prim>ies ,p#a & ,p#b are connect$ to ! l9e ,l1 "o ?r\gh a cond5s] ,c ( small capacity1 & ! o!r directly4 ,! prim>ies are provid$ ) second>ies ,s#a & ,s#b :i* are 9 s]ies ) ! en]giz+ circuits1 ,a#b & ,b#b & a motor ,m#c1 ! cond5s] ,c aga9 s]v+ to produce ! requisite diff]5ce 9 ! phase ( ! curr5ts trav]s+ ! motor circuits4 ,z su* phase motors ) two or m circuits are n[ well kn[n 9 ! art1 !y h be5 "h illu/rat$ diagrammatically4 ,no difficulty :atev] is f\nd 9 op]at+ a motor 9 ! mann] indicat$1 or 9 simil> ways2 & al?\gh su* exp]im5ts up to ?is day pres5t only sci5tific int]e/1 !y may at a p]iod n f> di/ant1 be c>ri$ out ) practical objects 9 view4 ,x is ?\ght useful to devote "h a few rem>ks to ! subject ( op]at+ devices ( all k9ds by means ( only "o lead+ wire4 ,x is q obvi\s1 t :5 high-frequ5cy curr5ts are made use (1 gr\nd connections are--at lea/ :5 ! ,e4 ,m4 ,f4 ( ! curr5ts is great--bett] ?an a return wire4 ,su* gr\nd connections are objectionable ) /eady or l[ frequ5cy curr5ts on acc\nt ( de/ructive *emical actions ( ! =m] & di/urb+ influ5ces ex]t$ by bo? on ! neighbor+ circuits2 b ) high frequ5cies ^! actions practically d n exi/4 ,/ill1 ev5 gr\nd connections become sup]flu\s :5 ! ,e4 ,m4 ,f4 is v high1 = soon a condition is rea*$1 :5 ! curr5t may be pass$ m economically ?r\gh op51 ?an ?r\gh clos$1 conductors4 ,remote z might seem an indu/rial application ( su* s+le wire transmission ( en]gy to "o n exp]i5c$ 9 su* l9es ( exp]im5t1 x w n seem s to anyone :o = "s "t has c>ri$ on inve/igations ( su* nature4 ,inde$ ,i _c see :y su* a plan %\ld n be practicable4 ,nor %\ld x be ?\ght t = c>ry+ out su* a plan curr5ts ( v high frequ5cy are expressly requir$1 = j z soon z pot5tials ( say #cj1jjj volts are us$1 ! s+le wire transmission may be effect$ ) l[ frequ5cies1 & exp]im5ts h be5 made by me f :i* ^! inf]5ces are made4 ,:5 ! frequ5cies are v high x has be5 f\nd 9 laboratory practice q easy to regulate ! effects 9 ! mann] %[n 9 diagram ,fig4 #aha4 ,"h two prim>ies ,p & ,p#a are %[n1 ea* connect$ ) "o ( its ends to ! l9e ,l & ) ! o!r end to ! cond5s] plates ,c & ,c1 respectively4 ,ne> ^! are plac$ o!r cond5s] plates ,c#a & ,c#a1 ! =m] be+ connect$ to ! l9e ,l & ! latt] to an insulat$ l>g] plate ,p#b4 ,on ! prim>ies are w\nd second>ies ,s & ,s#a1 ( co>se wire1 connect$ to ! devices d & l respectively4 ,by v>y+ ! di/ances ( ! cond5s] plates ,c & ,c#a1 & ,c & ,c#a ! curr5ts ?r\gh ! second>ies ,s & ,s#a are v>i$ 9 int5sity4 ,! curi\s feature is ! great s5sitiv5ess1 ! slighte/ *ange 9 ! di/ance ( ! plates produc+ consid]able v>iations 9 ! int5sity or /r5g? ( ! curr5ts4 ,! s5sitiv5ess may be r5d]$ extreme by mak+ ! frequ5cy su*1 t ! prim>y itself1 )\t any plate atta*$ to its free end1 satisfies1 9 conjunction ) ! clos$ second>y1 ! condition ( resonance4 ,9 su* condition an extremely small *ange 9 ! capacity ( ! free t]m9al produces great v>iations4 ,= in/ance1 ,i h be5 able to adju/ ! conditions s t ! m]e approa* ( a p]son to ! coil produces a consid]able *ange 9 ! brightness ( ! lamps atta*$ to ! second>y4 ,su* obs]vations & exp]im5ts possess1 ( c\rse1 at pres5t1 *iefly sci5tific int]e/1 b !y may soon become ( practical importance4 ,v high frequ5cies are ( c\rse n practicable ) motors on acc\nt ( ! necessity ( employ+ iron cores4 ,b "o may use sudd5 dis*>ges ( l[ frequ5cy & ?us obta9 c]ta9 advantages ( high-frequ5cy curr5ts )\t r5d]+ ! iron core entirely incapable ( foll[+ ! *anges & )\t entail+ a v great exp5diture ( en]gy 9 ! core4 ,i h f\nd x q practicable to op]ate ) su* l[ frequ5cy disruptive dis*>ges ( cond5s]s1 alt]nat+-curr5t motors4 ,a c]ta9 class ( su* motors :i* ,i advanc$ a few ye>s ago1 :i* conta9 clos$ second>y circuits1 w rotate q vigor\sly :5 ! dis*>ges are direct$ ?r\gh ! excit+ coils4 ,"o reason t su* a motor op]ates s well ) ^! dis*>ges is t ! diff]5ce ( phase betwe5 ! prim>y & second>y curr5ts is #ij degrees1 :i* is g5]ally n ! case ) h>monically ris+ & fall+ curr5ts ( l[ frequ5cy4 ,x might n be )\t int]e/ to %[ an exp]im5t ) a simple motor ( ?is k9d1 inasmu* z x is commonly ?\ght t disruptive dis*>ges are unsuitable = su* purposes4 ,! motor is illu/rat$ 9 ,fig4 #ahb4 ,x comprises a r l>ge iron core i ) slots on ! top into :i* are emb$d$ ?ick copp] wa%]s c c4 ,9 proximity to ! core is a freely-movable metal disc ,d4 ,! core is provid$ ) a prim>y excit+ coil ,c#a ! ends a & b ( :i* are connect$ to ! t]m9als ( ! second>y ,s ( an ord9>y trans=m]1 ! prim>y ,p ( ! latt] be+ connect$ to an alt]nat+ di/ribution circuit or g5]ator ,g ( l[ or mod]ate frequ5cy4 ,! t]m9als ( ! second>y ,s are atta*$ to a cond5s] ,c :i* dis*>ges ?r\gh an air gap d d :i* may be plac$ 9 s]ies or %unt to ! coil ,c#a4 ,:5 ! conditions are prop]ly *os5 ! disc ,d rotates ) consid]able ef=t & ! iron core i does n get v p]ceptibly hot4 ,) curr5ts f a high-frequ5cy alt]nator1 on ! contr>y1 ! core gets rapidly hot & ! disc rotates ) a mu* small] ef=t4 ,to p]=m ! exp]im5t prop]ly x %\ld be fir/ asc]ta9$ t ! disc ,d is n set 9 rotation :5 ! dis*>ge is n occurr+ at d d4 ,x is pref]able to use a l>ge iron core & a cond5s] ( l>ge capacity s z to br+ ! sup]impos$ quick] oscillation to a v l[ pit* or to d away ) x entirely4 ,by obs]v+ c]ta9 elem5t>y rules ,i h also f\nd x practicable to op]ate ord9>y s]ies or %unt direct-curr5t motors ) su* disruptive dis*>ges1 & ?is c be done ) or )\t a return wire4 ,,imp$ance ,,ph5om5a4 ,among ! v>i\s curr5t ph5om5a obs]v$1 p]haps ! mo/ int]e/+ are ^? ( imp$ance pres5t$ by conductors to curr5ts v>y+ at a rapid rate4 ,9 my fir/ pap] be=e ! ,am]ican ,in/itute ( ,electrical ,eng9e]s1 ,i h describ$ a few /rik+ obs]vations ( ?is k9d4 ,?us ,i %[$ t :5 su* curr5ts or sudd5 dis*>ges are pass$ ?r\gh a ?ick metal b> !re may be po9ts on ! b> only a few in*es ap>t1 :i* h a suffici5t pot5tial diff]5ce betwe5 !m to ma9ta9 at bright inc&esc5ce an ord9>y filam5t lamp4 ,i h also describ$ ! curi\s behavior ( r>efi$ gas surr\nd+ a conductor1 due to su* sudd5 ru%es ( curr5t4 ,^! ph5om5a h s9ce be5 m c>efully /udi$ & "o or two novel exp]im5ts ( ?is k9d are deem$ ( suffici5t int]e/ to be describ$ "h4 ,ref]r+ to ,fig4 #ahc;a1 ,b & ,b#a are v /\t copp] b>s connect$ at _! l[] ends to plates ,c & ,c#a1 respectively1 ( a cond5s]1 ! opposite plates ( ! latt] be+ connect$ to ! t]m9als ( ! second>y ,s ( a high-t5sion trans=m]1 ! prim>y ,p ( :i* is suppli$ ) alt]nat+ curr5ts f an ord9>y l[-frequ5cy dynamo ,g or di/ribution circuit4 ,! cond5s] dis*>ges ?r\gh an adju/able gap d d z usual4 ,by e/abli%+ a rapid vibration x 0 f\nd q easy to p]=m ! foll[+ curi\s exp]im5t4 ,! b>s ,b & ,b#a 7 jo9$ at ! top by a l[-voltage lamp l#c2 a little l[] 0 plac$ by means ( clamps c c1 a #ej-volt lamp l#b2 & /ill l[] ano!r #ajj-volt lamp l#a2 & f9ally1 at a c]ta9 di/ance bel[ ! latt] lamp1 an exhau/$ tube ,t4 ,by c>efully det]m9+ ! positions ( ^! devices x 0 f\nd practicable to ma9ta9 !m all at _! prop] illum9at+ p[]4 ,yet !y 7 all connect$ 9 multiple arc to ! two /\t copp] b>s & requir$ widely diff]5t pressures4 ,?is exp]im5t requires ( c\rse "s "t = adju/m5t b is q easily p]=m$4 ,illu/ration3 ,,figs4 #ahc;a1 #ahc;b & #ahc;c4 ,9 ,figs4 #ahc;b & #ahc;c1 two o!r exp]im5ts are illu/rat$ :i*1 unlike ! previ\s exp]im5t1 d n require v c>eful adju/m5ts4 ,9 ,fig4 #ahc;b1 two lamps1 l#a & l#b1 ! =m] a #ajj-volt & ! latt] a #ej-volt are plac$ 9 c]ta9 positions z indicat$1 ! #ajj-volt lamp be+ bel[ ! #ej-volt lamp4 ,:5 ! arc is play+ at d d & ! sudd5 dis*>ges are pass$ ?r\gh ! b>s ,b ,b#a1 ! #ej-volt lamp w1 z a rule1 burn brightly1 or at lea/ ?is result is easily secur$1 :ile ! #ajj-volt lamp w burn v l[ or rema9 q d>k1 ,fig4 #ahc;b4 ,n[ ! b>s ,b ,b#a may be jo9$ at ! top by a ?ick cross b> ,b#b & x is q easy to ma9ta9 ! #ajj-volt lamp at full c&le-p[] :ile ! #ej-volt lamp rema9s d>k1 ,fig4 #ahc;c4 ,^! results1 z ,i h po9t$ out previ\sly1 %\ld n be consid]$ to be due exactly to frequ5cy b r to ! "t rate ( *ange :i* may be great1 ev5 ) l[ frequ5cies4 ,a great _m o!r results ( ! same k9d1 equally int]e/+1 especially to ^? :o are only us$ to manipulate /eady curr5ts1 may be obta9$ & !y af=d preci\s clues 9 inve/igat+ ! nature ( electric curr5ts4 ,9 ! prec$+ exp]im5ts ,i h already _h occasion to %[ "s light ph5om5a & x w\ld n[ be prop] to /udy ^! 9 p>ticul>2 b to make ?is inve/igation m complete ,i ?9k x necess>y to make fir/ a few rem>ks on ! subject ( electrical resonance :i* has to be always obs]v$ 9 c>ry+ out ^! exp]im5ts4 ,,on ,,electrical ,,resonance4 ,! effects ( resonance are be+ m & m not$ by eng9e]s & are becom+ ( great importance 9 ! practical op]ation ( app>atus ( all k9ds ) alt]nat+ curr5ts4 ,a few g5]al rem>ks may !re=e be made conc]n+ ^! effects4 ,x is cle>1 t if we succe$ 9 employ+ ! effects ( resonance practically 9 ! op]ation ( electric devices ! return wire w1 z a matt] ( c\rse1 become unnecess>y1 = ! electric vibration may be convey$ ) "o wire j z well z1 & sometimes ev5 bett] ?an1 ) two4 ,! "q fir/ to answ] is1 !n1 :e!r pure resonance effects are producible4 ,!ory & exp]im5t bo? %[ t su* is impossible 9 ,nature1 = z ! oscillation becomes m & m vigor\s1 ! losses 9 ! vibrat+ bodies & environ+ m$ia rapidly increase & necess>ily *eck ! vibration :i* o!rwise w\ld g on increas+ =ev]4 ,x is a =tunate circum/ance t pure resonance is n producible1 = if x 7 !re is no tell+ :at dang]s might n lie 9 wait = ! innoc5t exp]im5t]4 ,b to a c]ta9 degree resonance is producible1 ! magnitude ( ! effects be+ limit$ by ! imp]fect conductivity & imp]fect ela/icity ( ! m$ia or1 g5]ally /at$1 by frictional losses4 ,! small] ^! losses1 ! m /rik+ are ! effects4 ,! same is ! case 9 me*anical vibration4 ,a /\t /eel b> may be set 9 vibration by drops ( wat] fall+ ^u x at prop] int]vals2 & ) glass1 :i* is m p]fectly ela/ic1 ! resonance effect is /ill m rem>kable1 = a goblet may be bur/ by s++ into x a note ( ! prop] pit*4 ,! electrical resonance is ! m p]fectly atta9$1 ! small] ! resi/ance or ! imp$ance ( ! conduct+ pa? & ! m p]fect ! dielectric4 ,9 a ,leyd5 j> dis*>g+ ?r\gh a %ort /r&$ cable ( ?9 wires ^! requirem5ts are probably be/ fulfill$1 & ! resonance effects are !re=e v prom95t4 ,su* is n ! case ) dynamo ma*9es1 trans=m]s & _! circuits1 or ) comm]cial app>atus 9 g5]al 9 :i* ! pres5ce ( iron cores complicates ! action or r5d]s x impossible4 ,9 reg>d to ,leyd5 j>s ) :i* resonance effects are frequ5tly demon/rat$1 ,i w\ld say t ! effects obs]v$ are (t5 attribut$ b are seldom due to true resonance1 = an error is q easily made 9 ?is respect4 ,?is may be und\bt$ly demon/rat$ by ! foll[+ exp]im5t4 ,take1 = in/ance1 two l>ge insulat$ metallic plates or sph]es :i* ,i %all designate ,a & ,b2 place !m at a c]ta9 small di/ance ap>t & *>ge !m f a frictional or influ5ce ma*9e to a pot5tial s high t j a slight increase ( ! diff]5ce ( pot5tial betwe5 !m w cause ! small air or insulat+ space to break d[n4 ,?is is easily rea*$ by mak+ a few prelim9>y trials4 ,if n[ ano!r plate--fa/5$ on an insulat+ h&le & connect$ by a wire to "o ( ! t]m9als ( a high t5sion second>y ( an induction coil1 :i* is ma9ta9$ 9 action by an alt]nator 7pref]ably high frequ5cy7--is approa*$ to "o ( ! *>g$ bodies ,a or ,b1 s z to be ne>] to ei!r "o ( !m1 ! dis*>ge w inv>iably occur betwe5 !m2 at lea/ x w1 if ! pot5tial ( ! coil 9 connection ) ! plate is suffici5tly high4 ,b ! explanation ( ?is w soon be f\nd 9 ! fact t ! approa*$ plate acts inductively ^u ! bodies ,a & ,b & causes a sp>k to pass betwe5 !m4 ,:5 ?is sp>k occurs1 ! *>ges :i* 7 previ\sly imp>t$ to ^! bodies f ! influ5ce ma*9e1 mu/ ne$s be lo/1 s9ce ! bodies are br\ght 9 electrical connection ?r\gh ! arc =m$4 ,n[ ?is arc is =m$ :e!r !re be resonance or n4 ,b ev5 if ! sp>k w\ld n be produc$1 /ill !re is an alt]nat+ ,e4 ,m4 ,f4 set up betwe5 ! bodies :5 ! plate is br\ght ne> "o ( !m2 !re=e ! approa* ( ! plate1 if x does n always actually1 w1 at any rate1 t5d to break d[n ! air space by inductive action4 ,in/ead ( ! sph]es or plates ,a & ,b we may take ! coat+s ( a ,leyd5 j> ) ! same result1 & 9 place ( ! ma*9e1--:i* is a high frequ5cy alt]nator pref]ably1 because x is m suitable = ! exp]im5t & also = ! argum5t1--we may take ano!r ,leyd5 j> or batt]y ( j>s4 ,:5 su* j>s are dis*>g+ ?r\gh a circuit ( l[ resi/ance ! same is trav]s$ by curr5ts ( v high frequ5cy4 ,! plate may n[ be connect$ to "o ( ! coat+s ( ! second j>1 & :5 x is br\ght ne> to ! fir/ j> j previ\sly *>g$ to a high pot5tial f an influ5ce ma*9e1 ! result is ! same z be=e1 & ! fir/ j> w dis*>ge ?r\gh a small air space ^u ! second be+ caus$ to dis*>ge4 ,b bo? j>s & _! circuits ne$ n be tun$ any clos] ?an a basso pr(undo is to ! note produc$ by a mosquito1 z small sp>ks w be produc$ ?r\gh ! air space1 or at lea/ ! latt] w be consid]ably m /ra9$ ow+ to ! sett+ up ( an alt]nat+ ,e4 ,m4 ,f4 by induction1 :i* takes place :5 "o ( ! j>s beg9s to dis*>ge4 ,aga9 ano!r error ( a simil> nature is q easily made4 ,if ! circuits ( ! two j>s are run p>allel & close toge!r1 & ! exp]im5t has be5 p]=m$ ( dis*>g+ "o by ! o!r1 & n[ a coil ( wire be add$ to "o ( ! circuits :]eupon ! exp]im5t does n succe$1 ! conclusion t ?is is due to ! fact t ! circuits are n[ n tun$1 w\ld be f> f be+ safe4 ,= ! two circuits act z cond5s] coat+s & ! addition ( ! coil to "o ( !m is equival5t to bridg+ !m1 at ! po9t :]e ! coil is plac$1 by a small cond5s]1 & ! effect ( ! latt] might be to prev5t ! sp>k f jump+ ?r\gh ! dis*>ge space by dim9i%+ ! alt]nat+ ,e4 ,m4 ,f4 act+ across ! same4 ,all ^! rem>ks1 & _m m :i* might be add$ b = fe> ( w&]+ too f> f ! subject1 are made ) ! p>donable int5tion ( caution+ ! unsuspect+ /ud5t1 :o might ga9 an entirely unw>rant$ op9ion ( 8 skill at see+ e exp]im5t succe$2 b !y are 9 no way ?ru/ ^u ! exp]i5c$ z novel obs]vations4 ,9 ord] to make reliable obs]vations ( electric resonance effects x is v desirable1 if n necess>y1 to employ an alt]nator giv+ curr5ts :i* rise & fall h>monically1 z 9 work+ ) make & break curr5ts ! obs]vations are n always tru/wor?y1 s9ce _m ph5om5a1 :i* dep5d on ! rate ( *ange1 may be produc$ ) widely diff]5t frequ5cies4 ,ev5 :5 mak+ su* obs]vations ) an alt]nator "o is apt to be mi/ak54 ,:5 a circuit is connect$ to an alt]nator !re are an indef9ite numb] ( values = capacity & self-induction :i*1 9 conjunction1 w satisfy ! condition ( resonance4 ,s !re are 9 me*anics an inf9ite numb] ( tun+ =ks :i* w respond to a note ( a c]ta9 pit*1 or load$ spr+s :i* h a def9ite p]iod ( vibration4 ,b ! resonance w be mo/ p]fectly atta9$ 9 t case 9 :i* ! motion is effect$ ) ! greate/ fre$om4 ,n[ 9 me*anics1 consid]+ ! vibration 9 ! common m$ium--t is1 air--x is ( comp>atively little importance :e!r "o tun+ =k be some:at l>g] ?an ano!r1 because ! losses 9 ! air are n v consid]able4 ,"o may1 ( c\rse1 enclose a tun+ =k 9 an exhau/$ vessel & by ?us r$uc+ ! air resi/ance to a m9imum obta9 bett] resonant action4 ,/ill ! diff]5ce w\ld n be v great4 ,b x w\ld make a great diff]5ce if ! tun+ =k 7 imm]s$ 9 m]cury4 ,9 ! electrical vibration x is ( enorm\s importance to arrange ! conditions s t ! vibration is effect$ ) ! greate/ fre$om4 ,! magnitude ( ! resonance effect dep5ds1 "u o!rwise equal conditions1 on ! quantity ( electricity set 9 motion or on ! /r5g? ( ! curr5t driv5 ?r\gh ! circuit4 ,b ! circuit opposes ! passage ( ! curr5ts by reason ( its imp$ance & !re=e1 to secure ! be/ action x is necess>y to r$uce ! imp$ance to a m9imum4 ,x is impossible to ov]come x entirely1 b m]ely 9 "p1 = ! ohmic resi/ance _c be ov]come4 ,b :5 ! frequ5cy ( ! impulses is v great1 ! fl[ ( ! curr5t is practically det]m9$ by self-induction4 ,n[ self-induction c be ov]come by comb9+ x ) capacity4 ,if ! relation betwe5 ^! is su*1 t at ! frequ5cy us$ !y annul ea* o!r1 t is1 h su* values z to satisfy ! condition ( resonance1 & ! greate/ quantity ( electricity is made to fl[ ?r\gh ! ext]nal circuit1 !n ! be/ result is obta9$4 ,x is simpl] & saf] to jo9 ! cond5s] 9 s]ies ) ! self-induction4 ,x is cle> t 9 su* comb9ations !re w be1 = a giv5 frequ5cy1 & consid]+ only ! fundam5tal vibration1 values :i* w give ! be/ result1 ) ! cond5s] 9 %unt to ! self-induction coil2 ( c\rse m su* values ?an ) ! cond5s] 9 s]ies4 ,b practical conditions det]m9e ! selection4 ,9 ! latt] case 9 p]=m+ ! exp]im5ts "o may take a small self-induction & a l>ge capacity or a small capacity & a l>ge self-induction1 b ! latt] is pref]able1 because x is inconv5i5t to adju/ a l>ge capacity by small /eps4 ,by tak+ a coil ) a v l>ge self-induction ! critical capacity is r$uc$ to a v small value1 & ! capacity ( ! coil itself may be suffici5t4 ,x is easy1 especially by obs]v+ c]ta9 artifices1 to w9d a coil ?r\gh :i* ! imp$ance w be r$uc$ to ! value ( ! ohmic resi/ance only2 & = any coil !re is1 ( c\rse1 a frequ5cy at :i* ! maximum curr5t w be made to pass ?r\gh ! coil4 ,! obs]vation ( ! relation betwe5 self-induction1 capacity & frequ5cy is becom+ important 9 ! op]ation ( alt]nate curr5t app>atus1 su* z trans=m]s or motors1 because by a judici\s det]m9ation ( ! elem5ts ! employm5t ( an exp5sive cond5s] becomes unnecess>y4 ,?us x is possible to pass ?r\gh ! coils ( an alt]nat+ curr5t motor "u ! normal work+ conditions ! requir$ curr5t ) a l[ ,e4 ,m4 ,f4 & d away entirely ) ! false curr5t1 & ! l>g] ! motor1 ! easi] su* a plan becomes practicable2 b x is necess>y = ?is to employ curr5ts ( v high pot5tial or high frequ5cy4 ,illu/ration3 ,,fig4 #ahd4 ,9 ,fig4 #ahd ,i4 is %[n a plan :i* has be5 foll[$ 9 ! /udy ( ! resonance effects by means ( a high frequ5cy alt]nator4 ,c#a is a coil ( _m turns1 :i* is divid$ into small sep>ate sections = ! purpose ( adju/m5t4 ,! f9al adju/m5t 0 made sometimes ) a few ?9 iron wires 7?\gh ?is is n always advisable7 or ) a clos$ second>y4 ,! coil ,c#a is connect$ ) "o ( its ends to ! l9e ,l f ! alt]nator ,g & ) ! o!r end to "o ( ! plates c ( a cond5s] c c#a1 ! plate 7c#a7 ( ! latt] be+ connect$ to a mu* l>g] plate ,p#a4 ,9 ?is mann] bo? capacity & self-induction 7 adju/$ to suit ! dynamo frequ5cy4 ,z reg>ds ! rise ( pot5tial ?r\gh resonant action1 ( c\rse1 !oretically1 x may am\nt to any?+ s9ce x dep5ds on self-induction & resi/ance & s9ce ^! may h any value4 ,b 9 practice "o is limit$ 9 ! selection ( ^! values & besides ^!1 !re are o!r limit+ causes4 ,"o may />t )1 say1 #a1jjj volts & raise ! ,e4 ,m4 ,f4 to #ej times t value1 b "o _c />t ) #ajj1jjj & raise x to t5 times t value because ( ! losses 9 ! m$ia :i* are great1 especially if ! frequ5cy is high4 ,x %\ld be possible to />t )1 = in/ance1 two volts f a high or l[ frequ5cy circuit ( a dynamo & raise ! ,e4 ,m4 ,f4 to _m hundr$ times t value4 ,?us coils ( ! prop] dim5sions might be connect$ ea* ) only "o ( its ends to ! ma9s f a ma*9e ( l[ ,e4 ,m4 ,f41 & ?\gh ! circuit ( ! ma*9e w\ld n be clos$ 9 ! ord9>y acceptance ( ! t]m1 yet ! ma*9e might be burn$ out if a prop] resonance effect w\ld be obta9$4 ,i h n be5 able to produce1 nor h ,i obs]v$ ) curr5ts f a dynamo ma*9e1 su* great rises ( pot5tial4 ,x is possible1 if n probable1 t ) curr5ts obta9$ f app>atus conta9+ iron ! di/urb+ influ5ce ( ! latt] is ! cause t ^! !oretical possibilities _c be realiz$4 ,b if su* is ! case ,i attribute x solely to ! hy/]esis & ,f\cault curr5t losses 9 ! core4 ,g5]ally x 0 necess>y to trans=m upw>d1 :5 ! ,e4 ,m4 ,f4 0 v l[1 & usually an ord9>y =m ( induction coil 0 employ$1 b sometimes ! arrangem5t illu/rat$ 9 ,fig4 #ahd ,,ii41 has be5 f\nd to be conv5i5t4 ,9 ?is case a coil ,c is made 9 a great _m sections1 a few ( ^! be+ us$ z a prim>y4 ,9 ?is mann] bo? prim>y & second>y are adju/able4 ,"o end ( ! coil is connect$ to ! l9e ,l#a f ! alt]nator1 & ! o!r l9e ,l is connect$ to ! int]m$iate po9t ( ! coil4 ,su* a coil ) adju/able prim>y & second>y w be f\nd also conv5i5t 9 exp]im5ts ) ! disruptive dis*>ge4 ,:5 true resonance is obta9$ ! top ( ! wave mu/ ( c\rse be on ! free end ( ! coil z1 = in/ance1 at ! t]m9al ( ! phosphoresc5ce bulb ,b4 ,?is is easily recogniz$ by obs]v+ ! pot5tial ( a po9t on ! wire w ne> to ! coil4 ,9 connection ) resonance effects & ! problem ( transmission ( en]gy ov] a s+le conductor :i* 0 previ\sly consid]$1 ,i w\ld say a few words on a subject :i* con/antly fills my ?\ghts & :i* conc]ns ! welf>e ( all4 ,i mean ! transmission ( intelligible signals or p]haps ev5 p[] to any di/ance )\t ! use ( wires4 ,i am becom+ daily m conv9c$ ( ! practicability ( ! s*eme2 & ?\gh ,i "k full well t ! great majority ( sci5tific m5 w n believe t su* results c be practically & imm$iately realiz$1 yet ,i ?9k t all consid] ! developm5ts 9 rec5t ye>s by a numb] ( work]s to h be5 su* z to enc\rage ?\ght & exp]im5t 9 ?is direction4 ,my conviction has gr[n s /rong1 t ,i no long] look ^u ?is plan ( en]gy or intellig5ce transmission z a m]e !oretical possibility1 b z a s]i\s problem 9 electrical eng9e]+1 :i* mu/ be c>ri$ out "s day4 ,! idea ( transmitt+ intellig5ce )\t wires is ! natural outcome ( ! mo/ rec5t results ( electrical inve/igations4 ,"s en?usia/s h express$ _! belief t telephony to any di/ance by induction ?r\gh ! air is possible4 ,i _c /ret* my imag9ation s f>1 b ,i d firmly believe t x is practicable to di/urb by means ( p[]ful ma*9es ! electro/atic condition ( ! e>? & ?us transmit intelligible signals & p]haps p[]4 ,9 fact1 :at is !re aga9/ ! c>ry+ out ( su* a s*eme8 ,we n[ "k t electric vibration may be transmitt$ ?r\gh a s+le conductor4 ,:y !n n try to avail ourselves ( ! e>? = ?is purpose8 ,we ne$ n be fright5$ by ! idea ( di/ance4 ,to ! we>y w&]] c\nt+ ! mile-po/s ! e>? may appe> v l>ge1 b to t happie/ ( all m51 ! a/ronom]1 :o gazes at ! heav5s & by _! /&>d judges ! magnitude ( our globe1 x appe>s v small4 ,& s ,i ?9k x mu/ seem to ! electrician1 = :5 he consid]s ! spe$ ) :i* an electric di/urbance is propagat$ ?r\gh ! e>? all 8 ideas ( di/ance mu/ completely vani%4 ,a po9t ( great importance w\ld be fir/ to "k :at is ! capacity ( ! e>?8 & :at *>ge does x conta9 if electrifi$8 ,?\gh we h no positive evid5ce ( a *>g$ body exi/+ 9 space )\t o!r oppositely electrifi$ bodies be+ ne>1 !re is a fair probability t ! e>? is su* a body1 = by :atev] process x 0 sep>at$ f o!r bodies--& ?is is ! accept$ view ( its orig9--x mu/ h reta9$ a *>ge1 z occurs 9 all processes ( me*anical sep>ation4 ,if x be a *>g$ body insulat$ 9 space its capacity %\ld be extremely small1 less ?an "o-?\s&? ( a f>ad4 ,b ! upp] /rata ( ! air are conduct+1 & s1 p]haps1 is ! m$ium 9 free space beyond ! atmosph]e1 & ^! may conta9 an opposite *>ge4 ,!n ! capacity might be incomp>ably great]4 ,9 any case x is ( ! greate/ importance to get an idea ( :at quantity ( electricity ! e>? conta9s4 ,x is difficult to say :e!r we %all ev] acquire ?is necess>y k1 b !re is hope t we may1 & t is1 by means ( electrical resonance4 ,if ev] we c asc]ta9 at :at p]iod ! e>?'s *>ge1 :5 di/urb$1 oscillates ) respect to an oppositely electrifi$ sy/em or kn[n circuit1 we %all "k a fact possibly ( ! greate/ importance to ! welf>e ( ! human race4 ,i propose to seek = ! p]iod by means ( an electrical oscillator1 or a s\rce ( alt]nat+ electric curr5ts4 ,"o ( ! t]m9als ( ! s\rce w\ld be connect$ to e>? z1 = in/ance1 to ! city wat] ma9s1 ! o!r to an insulat$ body ( l>ge surface4 ,x is possible t ! out] conduct+ air /rata1 or free space1 conta9 an opposite *>ge & t1 toge!r ) ! e>?1 !y =m a cond5s] ( v l>ge capacity4 ,9 su* case ! p]iod ( vibration may be v l[ & an alt]nat+ dynamo ma*9e might s]ve = ! purpose ( ! exp]im5t4 ,i w\ld !n trans=m ! curr5t to a pot5tial z high z x w\ld be f\nd possible & connect ! ends ( ! high t5sion second>y to ! gr\nd & to ! insulat$ body4 ,by v>y+ ! frequ5cy ( ! curr5ts & c>efully obs]v+ ! pot5tial ( ! insulat$ body & wat*+ = ! di/urbance at v>i\s neighbor+ po9ts ( ! e>?'s surface resonance might be detect$4 ,%\ld1 z ! majority ( sci5tific m5 9 all probability believe1 ! p]iod be extremely small1 !n a dynamo ma*9e w\ld n d & a prop] electrical oscillator w\ld h to be produc$ & p]haps x might n be possible to obta9 su* rapid vibrations4 ,b :e!r ?is be possible or n1 & :e!r ! e>? conta9s a *>ge or n1 & :atev] may be its p]iod ( vibration1 x c]ta9ly is possible--= ( ?is we h daily evid5ce--to produce "s electrical di/urbance suffici5tly p[]ful to be p]ceptible by suitable in/rum5ts at any po9t ( ! e>?'s surface4 ,illu/ration3 ,,fig4 #ahe4 ,assume t a s\rce ( alt]nat+ curr5t ,s be connect$1 z 9 ,fig4 #ahe1 ) "o ( its t]m9als to e>? 7conv5i5tly to ! wat] ma9s7 & ) ! o!r to a body ( l>ge surface ,p4 ,:5 ! electric oscillation is set up !re w be a movem5t ( electricity 9 & out ( ,p1 & alt]nat+ curr5ts w pass ?r\gh ! e>?1 conv]g+ to1 or div]g+ f1 ! po9t ,c :]e ! gr\nd connection is made4 ,9 ?is mann] neighbor+ po9ts on ! e>?'s surface )9 a c]ta9 radius w be di/urb$4 ,b ! di/urbance w dim9i% ) ! di/ance1 & ! di/ance at :i* ! effect w /ill be p]ceptible w dep5d on ! quantity ( electricity set 9 motion4 ,s9ce ! body ,p is insulat$1 9 ord] to displace a consid]able quantity1 ! pot5tial ( ! s\rce mu/ be excessive1 s9ce !re w\ld be limitations z to ! surface ( ,p4 ,! conditions might be adju/$ s t ! g5]ator or s\rce ,s w set up ! same electrical movem5t z ?\gh its circuit 7 clos$4 ,?us x is c]ta9ly practicable to impress an electric vibration at lea/ ( a c]ta9 l[ p]iod ^u ! e>? by means ( prop] ma*9]y4 ,at :at di/ance su* a vibration might be made p]ceptible c only be conjectur$4 ,i h on ano!r occasion consid]$ ! "q h[ ! e>? might behave to electric di/urbances4 ,!re is no d\bt t1 s9ce 9 su* an exp]im5t ! electrical d5sity at ! surface c\ld be b extremely small consid]+ ! size ( ! e>?1 ! air w\ld n act z a v di/urb+ factor1 & !re w\ld be n mu* en]gy lo/ ?r\gh ! action ( ! air1 :i* w\ld be ! case if ! d5sity 7 great4 ,!oretically1 !n1 x c\ld n require a great am\nt ( en]gy to produce a di/urbance p]ceptible at great di/ance1 or ev5 all ov] ! surface ( ! globe4 ,n[1 x is q c]ta9 t at any po9t )9 a c]ta9 radius ( ! s\rce ,s a prop]ly adju/$ self-induction & capacity device c be set 9 action by resonance4 ,b n only c ?is be done1 b ano!r s\rce ,s#a1 ,fig4 #ahe1 simil> to ,s1 or any numb] ( su* s\rces1 c be set to "w 9 syn*ronism ) ! latt]1 & ! vibration ?us int5sifi$ & spread ov] a l>ge area1 or a fl[ ( electricity produc$ to or f ! s\rce ,s#a if ! same be ( opposite phase to ! s\rce ,s4 ,i ?9k t beyond d\bt x is possible to op]ate electrical devices 9 a city ?r\gh ! gr\nd or pipe sy/em by resonance f an electrical oscillator locat$ at a c5tral po9t4 ,b ! practical solution ( ?is problem w\ld be ( incomp>ably small] b5efit to man ?an ! realization ( ! s*eme ( transmitt+ intellig5ce1 or p]haps p[]1 to any di/ance ?r\gh ! e>? or environ+ m$ium4 ,if ?is is at all possible1 di/ance does n mean any?+4 ,prop] app>atus mu/ fir/ be produc$ by means ( :i* ! problem c be attack$ & ,i h devot$ mu* ?\ght to ?is subject4 ,i am firmly conv9c$ t x c be done & hope t we %all live to see x done4 ,,on ,,! ,,light ,,ph5om5a ,,produc$ ,,by ,,high-,,frequ5cy ,,curr5ts ,,( ,,high ,,pot5tial ,,& ,,g5]al ,,rem>ks ,,relat+ ,,to ,,! ,,subject4 ,return+ n[ to ! light effects :i* x has be5 ! *ief object to inve/igate1 x is ?\ght prop] to divide ^! effects into f\r classes3 #a4 ,inc&esc5ce ( a solid4 #b4 ,phosphoresc5ce4 #c4 ,inc&esc5ce or phosphoresc5ce ( a r>efi$ gas2 & #d4 ,lum9osity produc$ 9 a gas at ord9>y pressure4 ,! fir/ "q is3 ,h[ are ^! lum9\s effects produc$8 ,9 ord] to answ] ?is "q z satisfactorily z ,i am able to d 9 ! light ( accept$ views & ) ! exp]i5ce acquir$1 & to add "s int]e/ to ?is demon/ration1 ,i %all dwell "h ^u a feature :i* ,i consid] ( great importance1 inasmu* z x promises1 besides1 to ?r[ a bett] light ^u ! nature ( mo/ ( ! ph5om5a produc$ by high-frequ5cy electric curr5ts4 ,i h on o!r occasions po9t$ out ! great importance ( ! pres5ce ( ! r>efi$ gas1 or atomic m$ium 9 g5]al1 ar\nd ! conductor ?r\gh :i* alt]nate curr5ts ( high frequ5cy are pass$1 z reg>ds ! heat+ ( ! conductor by ! curr5ts4 ,my exp]im5ts1 describ$ "s "t ago1 h %[n t1 ! high] ! frequ5cy & pot5tial diff]5ce ( ! curr5ts1 ! m important becomes ! r>efi$ gas 9 :i* ! conductor is imm]s$1 z a factor ( ! heat+4 ,! pot5tial diff]5ce1 h[ev]1 is1 z ,i !n po9t$ out1 a m important elem5t ?an ! frequ5cy4 ,:5 bo? ( ^! are suffici5tly high1 ! heat+ may be almo/ entirely due to ! pres5ce ( ! r>efi$ gas4 ,! exp]im5ts to foll[ w %[ ! importance ( ! r>efi$ gas1 or1 g5]ally1 ( gas at ord9>y or o!r pressure z reg>ds ! inc&esc5ce or o!r lum9\s effects produc$ by curr5ts ( ?is k9d4 ,i take two ord9>y #ej-volt #af ,c4 ,p4 lamps :i* are 9 e respect alike1 ) ! exception1 t "o has be5 op5$ at ! top & ! air has fill$ ! bulb1 :ile ! o!r is at ! ord9>y degree ( exhau/ion ( comm]cial lamps4 ,:5 ,i atta* ! lamp :i* is exhau/$ to ! t]m9al ( ! second>y ( ! coil1 :i* ,i h already us$1 z 9 exp]im5ts illu/rat$ 9 ,fig4 #agi;a = in/ance1 & turn on ! curr5t1 ! filam5t1 z y h be=e se51 comes to high inc&esc5ce4 ,:5 ,i atta* ! second lamp1 :i* is fill$ ) air1 in/ead ( ! =m]1 ! filam5t /ill gl[s1 b mu* less brightly4 ,?is exp]im5t illu/rates only 9 "p ! tru? ( ! /atem5ts be=e made4 ,! importance ( ! filam5t's be+ imm]s$ 9 r>efi$ gas is pla9ly noticeable b n to su* a degree z might be desirable4 ,! reason is t ! second>y ( ?is coil is w\nd = l[ t5sion1 hav+ only #aej turns1 & ! pot5tial diff]5ce at ! t]m9als ( ! lamp is !re=e small4 ,7 ,i to take ano!r coil ) _m m turns 9 ! second>y1 ! effect w\ld be increas$1 s9ce x dep5ds p>tially on ! pot5tial diff]5ce1 z be=e rem>k$4 ,b s9ce ! effect likewise dep5ds on ! frequ5cy1 x maybe prop]ly /at$ t x dep5ds on ! "t rate ( ! v>iation ( ! pot5tial diff]5ce4 ,! great] ?is v>iation1 ! m important becomes ! gas z an elem5t ( heat+4 ,i c produce a mu* great] rate ( v>iation 9 ano!r way1 :i*1 besides1 has ! advantage ( do+ away ) ! objections1 :i* might be made 9 ! exp]im5t j %[n1 ev5 if bo? ! lamps 7 connect$ 9 s]ies or multiple arc to ! coil1 namely1 t 9 consequ5ce ( ! reactions exi/+ betwe5 ! prim>y & second>y coil ! conclusions are r5d]$ unc]ta94 ,?is result ,i secure by *>g+1 f an ord9>y trans=m] :i* is f$ f ! alt]nat+ curr5t supply /ation1 a batt]y ( cond5s]s1 & dis*>g+ ! latt] directly ?r\gh a circuit ( small self-induction1 z be=e illu/rat$ 9 ,figs4 #ahc;a1 #ahc;b1 & #ahc;c4 ,illu/ration3 ,,fig4 #ahf;a4 ,illu/ration3 ,,fig4 #ahf;b4 ,illu/ration3 ,,fig4 #ahf;c4 ,9 ,figs4 #ahf;a1 #ahf;b & #ahf;c1 ! heavy copp] b>s ,b ,b#a1 are connect$ to ! opposite coat+s ( a batt]y ( cond5s]s1 or g5]ally 9 su* way1 t ! high frequ5cy or sudd5 dis*>ges are made to trav]se !m4 ,i connect fir/ an ord9>y #ej-volt inc&esc5t lamp to ! b>s by means ( ! clamps c c4 ,! dis*>ges be+ pass$ ?r\gh ! lamp1 ! filam5t is r5d]$ inc&esc5t1 ?\gh ! curr5t ?r\gh x is v small1 & w\ld n be ne>ly suffici5t to produce a visible effect "u ! conditions ( ord9>y use ( ! lamp4 ,in/ead ( ?is ,i n[ atta* to ! b>s ano!r lamp exactly l ! fir/1 b ) ! seal brok5 (f1 ! bulb be+ !re=e fill$ ) air at ord9>y pressure4 ,:5 ! dis*>ges are direct$ ?r\gh ! filam5t1 z be=e1 x does n become inc&esc5t4 ,b ! result might /ill be attribut$ to "o ( ! _m possible reactions4 ,i !re=e connect bo? ! lamps 9 multiple arc z illu/rat$ 9 ,fig4 #ahf;a4 ,pass+ ! dis*>ges ?r\gh bo? ! lamps1 aga9 ! filam5t 9 ! exhau/$ lamp l gl[s v brightly :ile t 9 ! non-exhau/$ lamp l#a rema9s d>k1 z previ\sly4 ,b x %\ld n be ?\ght t ! latt] lamp is tak+ only a small fraction ( ! en]gy suppli$ to bo? ! lamps2 on ! contr>y1 x may consume a consid]able portion ( ! en]gy & x may become ev5 hott] ?an ! "o :i* burns brightly4 ,9 ?is exp]im5t ! pot5tial diff]5ce at ! t]m9als ( ! lamps v>ies 9 sign !oretically ?ree to f\r million times a second4 ,! ends ( ! filam5ts are correspond+ly electrifi$1 & ! gas 9 ! bulbs is viol5tly agitat$ & a l>ge portion ( ! suppli$ en]gy is ?us conv]t$ into heat4 ,9 ! non-exhau/$ bulb1 !re be+ a few million times m gas molecules ?an 9 ! exhau/$ "o1 ! bomb>dm5t1 :i* is mo/ viol5t at ! ends ( ! filam5t1 9 ! neck ( ! bulb1 consumes a l>ge portion ( ! en]gy )\t produc+ any visible effect4 ,! reason is t1 !re be+ _m molecules1 ! bomb>dm5t is quantitatively consid]able1 b ! individual impacts are n v viol5t1 z ! spe$s ( ! molecules are comp>atively small ow+ to ! small free pa?4 ,9 ! exhau/$ bulb1 on ! contr>y1 ! spe$s are v great1 & ! individual impacts are viol5t & !re=e bett] adapt$ to produce a visible effect4 ,besides1 ! convection ( heat is great] 9 ! =m] bulb4 ,9 bo? ! bulbs ! curr5t trav]s+ ! filam5ts is v small1 incomp>ably small] ?an t :i* !y require on an ord9>y l[-frequ5cy circuit4 ,! pot5tial diff]5ce1 h[ev]1 at ! ends ( ! filam5ts is v great & might be possibly #bj1jjj volts or m1 if ! filam5ts 7 /raight & _! ends f> ap>t4 ,9 ! ord9>y lamp a sp>k g5]ally occurs betwe5 ! ends ( ! filam5t or betwe5 ! plat9um wires outside1 be=e su* a diff]5ce ( pot5tial c be rea*$4 ,x might be object$ t 9 ! exp]im5t be=e %[n ! lamps1 be+ 9 multiple arc1 ! exhau/$ lamp might take a mu* l>g] curr5t & t ! effect obs]v$ might n be exactly attributable to ! action ( ! gas 9 ! bulbs4 ,su* objections w lose mu* weight if ,i connect ! lamps 9 s]ies1 ) ! same result4 ,:5 ?is is done & ! dis*>ges are direct$ ?r\gh ! filam5ts1 x is aga9 not$ t ! filam5t 9 ! non-exhau/$ bulb l#a1 rema9s d>k1 :ile t 9 ! exhau/$ "o 7l7 gl[s ev5 m int5sely ?an "u its normal conditions ( work+1 ,fig4 #ahf;b4 ,accord+ to g5]al ideas ! curr5t ?r\gh ! filam5ts %\ld n[ be ! same1 7 x n modifi$ by ! pres5ce ( ! gas ar\nd ! filam5ts4 ,at ?is juncture ,i may po9t out ano!r int]e/+ feature1 :i* illu/rates ! effect ( ! rate ( *ange ( pot5tial ( ! curr5ts4 ,i w leave ! two lamps connect$ 9 s]ies to ! b>s ,b ,b#a1 z 9 ! previ\s exp]im5t1 ,fig4 #ahf;b1 b w pres5tly r$uce consid]ably ! frequ5cy ( ! curr5ts1 :i* 0 excessive 9 ! exp]im5t j be=e %[n4 ,?is ,i may d by ins]t+ a self-induction coil 9 ! pa? ( ! dis*>ges1 or by augm5t+ ! capacity ( ! cond5s]s4 ,:5 ,i n[ pass ^! l[-frequ5cy dis*>ges ?r\gh ! lamps1 ! exhau/$ lamp l aga9 is z bright z be=e1 b x is not$ also t ! non-exhau/$ lamp l#a gl[s1 ?\gh n q z int5sely z ! o!r4 ,r$uc+ ! curr5t ?r\gh ! lamps1 ,i may br+ ! filam5t 9 ! latt] lamp to r$ness1 &1 ?\gh ! filam5t 9 ! exhau/$ lamp l is bright1 ,fig4 #ahf;c1 ! degree ( its inc&esc5ce is mu* small] ?an 9 ,fig4 #ahf;b1 :5 ! curr5ts 7 ( a mu* high] frequ5cy4 ,9 ^! exp]im5ts ! gas acts 9 two opposite ways 9 det]m9+ ! degree ( ! inc&esc5ce ( ! filam5ts1 t is1 by convection & bomb>dm5t4 ,! high] ! frequ5cy & pot5tial ( ! curr5ts1 ! m important becomes ! bomb>dm5t4 ,! convection on ! contr>y %\ld be ! small]1 ! high] ! frequ5cy4 ,:5 ! curr5ts are /eady !re is practically no bomb>dm5t1 & convection may !re=e ) su* curr5ts also consid]ably modify ! degree ( inc&esc5ce & produce results simil> to ^? j be=e %[n4 ,?us1 if two lamps exactly alike1 "o exhau/$ & "o n exhau/$1 are connect$ 9 multiple arc or s]ies to a direct-curr5t ma*9e1 ! filam5t 9 ! non-exhau/$ lamp w require a consid]ably great] curr5t to be r5d]$ inc&esc5t4 ,?is result is entirely due to convection1 & ! effect is ! m prom95t ! ?9n] ! filam5t4 ,pr(essor ,ayrton & ,mr4 ,kilg\r "s "t ago publi%$ quantitative results conc]n+ ! !rmal emissivity by radiation & convection 9 :i* ! effect ) ?9 wires 0 cle>ly %[n4 ,?is effect may be /rik+ly illu/rat$ by prep>+ a numb] ( small1 %ort1 glass tubes1 ea* conta9+ ?r\gh its axis ! ?9ne/ obta9able plat9um wire4 ,if ^! tubes be highly exhau/$1 a numb] ( !m may be connect$ 9 multiple arc to a direct-curr5t ma*9e & all ( ! wires may be kept at inc&esc5ce ) a small] curr5t ?an t requir$ to r5d] inc&esc5t a s+le "o ( ! wires if ! tube be n exhau/$4 ,c\ld ! tubes be s highly exhau/$ t convection w\ld be nil1 !n ! relative am\nts ( heat giv5 (f by convection & radiation c\ld be det]m9$ )\t ! difficulties att5d+ !rmal quantitative measurem5ts4 ,if a s\rce ( electric impulses ( high frequ5cy & v high pot5tial is employ$1 a /ill great] numb] ( ! tubes may be tak5 & ! wires r5d]$ inc&esc5t by a curr5t n capable ( w>m+ p]ceptibly a wire ( ! same size imm]s$ 9 air at ord9>y pressure1 & convey+ ! en]gy to all ( !m4 ,i may "h describe a result :i* is /ill m int]e/+1 & to :i* ,i h be5 l$ by ! obs]vation ( ^! ph5om5a4 ,i not$ t small diff]5ces 9 ! d5sity ( ! air produc$ a consid]able diff]5ce 9 ! degree ( inc&esc5ce ( ! wires1 & ,i ?\ght t1 s9ce 9 a tube1 ?r\gh :i* a lum9\s dis*>ge is pass$1 ! gas is g5]ally n ( uni=m d5sity1 a v ?9 wire conta9$ 9 ! tube might be r5d]$ inc&esc5t at c]ta9 places ( small] d5sity ( ! gas1 :ile x w\ld rema9 d>k at ! places ( great] d5sity1 :]e ! convection w\ld be great] & ! bomb>dm5t less int5se4 ,accord+ly a tube t 0 prep>$1 z illu/rat$ 9 ,fig4 #ahg1 :i* conta9$ ?r\gh ! middle a v f9e plat9um wire w4 ,! tube 0 exhau/$ to a mod]ate degree & x 0 f\nd t :5 x 0 atta*$ to ! t]m9al ( a high-frequ5cy coil ! plat9um wire w w\ld inde$1 become inc&esc5t 9 pat*es1 z illu/rat$ 9 ,fig4 #ahg4 ,lat] a numb] ( ^! tubes ) "o or m wires 7 prep>$1 ea* %[+ ?is result4 ,! effect 0 be/ not$ :5 ! /riat$ dis*>ge occurr$ 9 ! tube1 b 0 also produc$ :5 ! /riae 7 n visible1 %[+ t1 ev5 !n1 ! gas 9 ! tube 0 n ( uni=m d5sity4 ,! position ( ! /riae 0 g5]ally su*1 t ! r>efactions correspond$ to ! places ( inc&esc5ce or great] brightness on ! wire w4 ,b 9 a few in/ances x 0 not$1 t ! bright spots on ! wire 7 cov]$ by ! d5se p>ts ( ! /riat$ dis*>ge z indicat$ by l 9 ,fig4 #ahg1 ?\gh ! effect 0 b>ely p]ceptible4 ,?is 0 expla9$ 9 a plausible way by assum+ t ! convection 0 n widely diff]5t 9 ! d5se & r>efi$ places1 & t ! bomb>dm5t 0 great] on ! d5se places ( ! /riat$ dis*>ge4 ,x is1 9 fact1 (t5 obs]v$ 9 bulbs1 t "u c]ta9 conditions a ?9 wire is br\ght to high] inc&esc5ce :5 ! air is n too highly r>efi$4 ,?is is ! case :5 ! pot5tial ( ! coil is n high en\gh = ! vacuum1 b ! result may be attribut$ to _m diff]5t causes4 ,9 all cases ?is curi\s ph5om5on ( inc&esc5ce disappe>s :5 ! tube1 or r ! wire1 acquires ?r\gh\t a uni=m temp]ature4 ,illu/ration3 ,,fig4 #ahg4 ,illu/ration3 ,,fig4 #ahh4 ,disreg>d+ n[ ! modify+ effect ( convection !re are !n two di/9ct causes :i* det]m9e ! inc&esc5ce ( a wire or filam5t ) v>y+ curr5ts1 t is1 conduction curr5t & bomb>dm5t4 ,) /eady curr5ts we h to deal only ) ! =m] ( ^! two causes1 & ! heat+ effect is a m9imum1 s9ce ! resi/ance is lea/ to /eady fl[4 ,:5 ! curr5t is a v>y+ "o ! resi/ance is great]1 & h5ce ! heat+ effect is increas$4 ,?us if ! rate ( *ange ( ! curr5t is v great1 ! resi/ance may increase to su* an ext5t t ! filam5t is br\ght to inc&esc5ce ) inappreciable curr5ts1 & we are able to take a %ort & ?ick block ( c>bon or o!r mat]ial & br+ x to bright inc&esc5ce ) a curr5t incomp>ably small] ?an t requir$ to br+ to ! same degree ( inc&esc5ce an ord9>y ?9 lamp filam5t ) a /eady or l[ frequ5cy curr5t4 ,?is result is important1 & illu/rates h[ rapidly our views on ^! subjects are *ang+1 & h[ quickly our field ( k is ext5d+4 ,9 ! art ( inc&esc5t light+1 to view ?is result 9 "o aspect only1 x has be5 commonly consid]$ z an ess5tial requirem5t = practical success1 t ! lamp filam5t %\ld be ?9 & ( high resi/ance4 ,b n[ we "k t ! resi/ance ( ! filam5t to ! /eady fl[ does n mean any?+2 ! filam5t might z well be %ort & ?ick2 = if x be imm]s$ 9 r>efi$ gas x w become inc&esc5t by ! passage ( a small curr5t4 ,x all dep5ds on ! frequ5cy & pot5tial ( ! curr5ts4 ,we may conclude f ?is1 t x w\ld be ( advantage1 s f> z ! lamp is consid]$1 to employ high frequ5cies = light+1 z !y all[ ! use ( %ort & ?ick filam5ts & small] curr5ts4 ,if a wire or filam5t be imm]s$ 9 a homog5e\s m$ium1 all ! heat+ is due to true conduction curr5t1 b if x be enclos$ 9 an exhau/$ vessel ! conditions are entirely diff]5t4 ,"h ! gas beg9s to act & ! heat+ effect ( ! conduction curr5t1 z is %[n 9 _m exp]im5ts1 may be v small comp>$ ) t ( ! bomb>dm5t4 ,?is is especially ! case if ! circuit is n clos$ & ! pot5tials are ( c\rse v high4 ,suppose t a f9e filam5t enclos$ 9 an exhau/$ vessel be connect$ ) "o ( its ends to ! t]m9al ( a high t5sion coil & ) its o!r end to a l>ge insulat$ plate4 ,?\gh ! circuit is n clos$1 ! filam5t1 z ,i h be=e %[n1 is br\ght to inc&esc5ce4 ,if ! frequ5cy & pot5tial be comp>atively l[1 ! filam5t is heat$ by ! curr5t pass+ ?r\gh x4 ,if ! frequ5cy & pot5tial1 & pr9cipally ! latt]1 be increas$1 ! insulat$ plate ne$ be b v small1 or may be done away ) entirely2 /ill ! filam5t w become inc&esc5t1 practically all ! heat+ be+ !n due to ! bomb>dm5t4 ,a practical way ( comb9+ bo? ! effects ( conduction curr5ts & bomb>dm5t is illu/rat$ 9 ,fig4 #ahh1 9 :i* an ord9>y lamp is %[n provid$ ) a v ?9 filam5t :i* has "o ( ! ends ( ! latt] connect$ to a %ade s]v+ ! purpose ( ! insulat$ plate1 & ! o!r end to ! t]m9al ( a high t5sion s\rce4 ,x %\ld n be ?\ght t only r>efi$ gas is an important factor 9 ! heat+ ( a conductor by v>y+ curr5ts1 b gas at ord9>y pressure may become important1 if ! pot5tial diff]5ce & frequ5cy ( ! curr5ts is excessive4 ,on ?is subject ,i h already /at$1 t :5 a conductor is fus$ by a /roke ( lightn+1 ! curr5t ?r\gh x may be exce$+ly small1 n ev5 suffici5t to heat ! conductor p]ceptibly1 7 ! latt] imm]s$ 9 a homog5e\s m$ium4 ,f ! prec$+ x is cle> t :5 a conductor ( high resi/ance is connect$ to ! t]m9als ( a s\rce ( high frequ5cy curr5ts ( high pot5tial1 !re may occur consid]able dissipation ( en]gy1 pr9cipally at ! ends ( ! conductor1 9 consequ5ce ( ! action ( ! gas surr\nd+ ! conductor4 ,ow+ to ?is1 ! curr5t ?r\gh a section ( ! conductor at a po9t midway betwe5 its ends may be mu* small] ?an ?r\gh a section ne> ! ends4 ,fur!rmore1 ! curr5t passes pr9cipally ?r\gh ! out] portions ( ! conductor1 b ?is effect is to be di/+ui%$ f ! sk9 effect z ord9>ily int]pret$1 = ! latt] w\ld1 or %\ld1 occur also 9 a cont9u\s incompressible m$ium4 ,if a great _m inc&esc5t lamps are connect$ 9 s]ies to a s\rce ( su* curr5ts1 ! lamps at ! ends may burn brightly1 :]eas ^? 9 ! middle may rema9 entirely d>k4 ,?is is due pr9cipally to bomb>dm5t1 z be=e /at$4 ,b ev5 if ! curr5ts be /eady1 provid$ ! diff]5ce ( pot5tial is v great1 ! lamps at ! end w burn m brightly ?an ^? 9 ! middle4 ,9 su* case !re is no rhy?mical bomb>dm5t1 & ! result is produc$ entirely by leakage4 ,?is leakage or dissipation into space :5 ! t5sion is high1 is consid]able :5 inc&esc5t lamps are us$1 & /ill m consid]able ) arcs1 = ! latt] act l flames4 ,g5]ally1 ( c\rse1 ! dissipation is mu* small] ) /eady1 ?an ) v>y+1 curr5ts4 ,i h contriv$ an exp]im5t :i* illu/rates 9 an int]e/+ mann] ! effect ( lat]al diffusion4 ,if a v long tube is atta*$ to ! t]m9al ( a high frequ5cy coil1 ! lum9osity is greate/ ne> ! t]m9al & falls (f gradually t[>ds ! remote end4 ,?is is m m>k$ if ! tube is n>r[4 ,a small tube ab\t "o-half in* 9 diamet] & twelve in*es long 7,fig4 #ahi71 has "o ( its ends drawn out into a f9e fibre f ne>ly ?ree feet long4 ,! tube is plac$ 9 a brass socket ,t :i* c be screw$ on ! t]m9al ,t#a ( ! induction coil4 ,! dis*>ge pass+ ?r\gh ! tube fir/ illum9ates ! bottom ( ! same1 :i* is ( comp>atively l>ge section2 b ?r\gh ! long glass fibre ! dis*>ge _c pass4 ,b gradually ! r>efi$ gas inside becomes w>m$ & m conduct+ & ! dis*>ge spreads into ! glass fibre4 ,?is spread+ is s sl[1 t x may take half a m9ute or m until ! dis*>ge has work$ ?r\gh up to ! top ( ! glass fibre1 !n pres5t+ ! appe>ance ( a /rongly lum9\s ?9 ?read4 ,by adju/+ ! pot5tial at ! t]m9al ! light may be made to travel upw>ds at any spe$4 ,once1 h[ev]1 ! glass fibre is heat$1 ! dis*>ge breaks ?r\gh its entire l5g? in/antly4 ,! int]e/+ po9t to be not$ is t1 ! high] ! frequ5cy ( ! curr5ts1 or 9 o!r words1 ! great] relatively ! lat]al dissipation1 at a sl[] rate may ! light be made to propagate ?r\gh ! fibre4 ,?is exp]im5t is be/ p]=m$ ) a highly exhau/$ & fre%ly made tube4 ,:5 ! tube has be5 us$ = "s "t ! exp]im5t (t5 fails4 ,x is possible t ! gradual & sl[ impairm5t ( ! vacuum is ! cause4 ,?is sl[ propagation ( ! dis*>ge ?r\gh a v n>r[ glass tube corresponds exactly to ! propagation ( heat ?r\gh a b> w>m$ at "o end4 ,! quick] ! heat is c>ri$ away lat]ally ! long] "t x w take = ! heat to w>m ! remote end4 ,:5 ! curr5t ( a l[ frequ5cy coil is pass$ ?r\gh ! fibre f end to end1 !n ! lat]al dissipation is small & ! dis*>ge in/antly breaks ?r\gh almo/ )\t exception4 ,illu/ration3 ,,fig4 #ahi4 ,illu/ration3 ,,fig4 #aij4 ,aft] ^! exp]im5ts & obs]vations :i* h %[n ! importance ( ! discont9uity or atomic /ructure ( ! m$ium & :i* w s]ve to expla91 9 a measure at lea/1 ! nature ( ! f\r k9ds ( light effects producible ) ^! curr5ts1 ,i may n[ give y an illu/ration ( ^! effects4 ,= ! sake ( int]e/ ,i may d ?is 9 a mann] :i* to _m ( y might be novel4 ,y h se5 be=e t we may n[ convey ! electric vibration to a body by means ( a s+le wire or conductor ( any k9d4 ,s9ce ! human frame is conduct+ ,i may convey ! vibration ?r\gh my body4 ,fir/1 z 9 "s previ\s exp]im5ts1 ,i connect my body ) "o ( ! t]m9als ( a high-t5sion trans=m] & take 9 my h& an exhau/$ bulb :i* conta9s a small c>bon button m\nt$ ^u a plat9um wire lead+ to ! outside ( ! bulb1 & ! button is r5d]$ inc&esc5t z soon z ! trans=m] is set to "w 7,fig4 #aij74 ,i may place a conduct+ %ade on ! bulb :i* s]ves to int5sify ! action1 b is n necess>y4 ,nor is x requir$ t ! button %\ld be 9 conduct+ connection ) ! h& ?r\gh a wire lead+ ?r\gh ! glass1 = suffici5t en]gy may be transmitt$ ?r\gh ! glass itself by inductive action to r5d] ! button inc&esc5t4 ,illu/ration3 ,,fig4 #aia4 ,illu/ration3 ,,fig4 #aib4 ,next ,i take a highly exhau/$ bulb conta9+ a /rongly phosphoresc5t body1 above :i* is m\nt$ a small plate ( alum9um on a plat9um wire lead+ to ! outside1 & ! curr5ts fl[+ ?r\gh my body excite int5se phosphoresc5ce 9 ! bulb 7,fig4 #aia74 ,next aga9 ,i take 9 my h& a simple exhau/$ tube1 & 9 ! same mann] ! gas inside ! tube is r5d]$ highly inc&esc5t or phosphoresc5t 7,fig4 #aib74 ,f9ally1 ,i may take 9 my h& a wire1 b>e or cov]$ ) ?ick insulation1 x is q immat]ial2 ! electrical vibration is s int5se z to cov] ! wire ) a lum9\s film 7,fig4 #aic74 ,illu/ration3 ,,fig4 #aic4 ,illu/ration3 ,,fig4 #aid4 ,illu/ration3 ,,fig4 #aie4 ,a few words mu/ n[ be devot$ to ea* ( ^! ph5om5a4 ,9 ! fir/ place1 ,i w consid] ! inc&esc5ce ( a button or ( a solid 9 g5]al1 & dwell ^u "s facts :i* apply equally to all ^! ph5om5a4 ,x 0 po9t$ out be=e t :5 a ?9 conductor1 su* z a lamp filam5t1 = in/ance1 is connect$ ) "o ( its ends to ! t]m9al ( a trans=m] ( high t5sion ! filam5t is br\ght to inc&esc5ce p>tly by a conduction curr5t & p>tly by bomb>dm5t4 ,! %ort] & ?ick] ! filam5t ! m important becomes ! latt]1 & f9ally1 r$uc+ ! filam5t to a m]e button1 all ! heat+ mu/ practically be attribut$ to ! bomb>dm5t4 ,s 9 ! exp]im5t be=e %[n1 ! button is r5d]$ inc&esc5t by ! rhy?mical impact ( freely movable small bodies 9 ! bulb4 ,^! bodies may be ! molecules ( ! residual gas1 p>ticles ( du/ or lumps torn f ! electrode2 :atev] !y are1 x is c]ta9 t ! heat+ ( ! button is ess5tially connect$ ) ! pressure ( su* freely movable p>ticles1 or ( atomic matt] 9 g5]al 9 ! bulb4 ,! heat+ is ! m int5se ! great] ! numb] ( impacts p] second & ! great] ! en]gy ( ea* impact4 ,yet ! button w\ld be heat$ also if x 7 connect$ to a s\rce ( a /eady pot5tial4 ,9 su* a case electricity w\ld be c>ri$ away f ! button by ! freely movable c>ri]s or p>ticles fly+ ab\t1 & ! quantity ( electricity ?us c>ri$ away might be suffici5t to br+ ! button to inc&esc5ce by its passage ?r\gh ! latt]4 ,b ! bomb>dm5t c\ld n be ( great importance 9 su* case4 ,= ?is reason x w\ld require a comp>atively v great supply ( en]gy to ! button to ma9ta9 x at inc&esc5ce ) a /eady pot5tial4 ,! high] ! frequ5cy ( ! electric impulses ! m economically c ! button be ma9ta9$ at inc&esc5ce4 ,"o ( ! *ief reasons :y ?is is s1 is1 ,i believe1 t ) impulses ( v high frequ5cy !re is less ex*ange ( ! freely movable c>ri]s ar\nd ! electrode & ?is means1 t 9 ! bulb ! heat$ matt] is bett] conf9$ to ! neighborhood ( ! button4 ,if a d\ble bulb1 z illu/rat$ 9 ,fig4 #aid be made1 compris+ a l>ge globe ,b & a small "o b1 ea* conta9+ z usual a filam5t f m\nt$ on a plat9um wire w & w#a1 x is f\nd1 t if ! filam5ts f f be exactly alike1 x requires less en]gy to keep ! filam5t 9 ! globe b at a c]ta9 degree ( inc&esc5ce1 ?an t 9 ! globe ,b4 ,?is is due to ! conf9em5t ( ! movable p>ticles ar\nd ! button4 ,9 ?is case x is also asc]ta9$1 t ! filam5t 9 ! small globe b is less det]iorat$ :5 ma9ta9$ a c]ta9 l5g? ( "t at inc&esc5ce4 ,?is is a necess>y consequ5ce ( ! fact t ! gas 9 ! small bulb becomes /rongly heat$ & !re=e a v good conductor1 & less "w is !n p]=m$ on ! button1 s9ce ! bomb>dm5t becomes less int5se z ! conductivity ( ! gas increases4 ,9 ?is con/ruction1 ( c\rse1 ! small bulb becomes v hot & :5 x rea*es an elevat$ temp]ature ! convection & radiation on ! outside increase4 ,on ano!r occasion ,i h %[n bulbs 9 :i* ?is drawback 0 l>gely avoid$4 ,9 ^! in/ances a v small bulb1 conta9+ a refractory button1 0 m\nt$ 9 a l>ge globe & ! space betwe5 ! walls ( bo? 0 highly exhau/$4 ,! out] l>ge globe rema9$ comp>atively cool 9 su* con/ructions4 ,:5 ! l>ge globe 0 on ! pump & ! vacuum betwe5 ! walls ma9ta9$ p]man5t by ! cont9u\s action ( ! pump1 ! out] globe w\ld rema9 q cold1 :ile ! button 9 ! small bulb 0 kept at inc&esc5ce4 ,b :5 ! seal 0 made1 & ! button 9 ! small bulb ma9ta9$ inc&esc5t "s l5g? ( "t1 ! l>ge globe too w\ld become w>m$4 ,f ?is ,i conjecture t if vacu\s space 7z ,pr(4 ,dew> f9ds7 _c convey heat1 x is s m]ely 9 virtue ( our rapid motion ?r\gh space or1 g5]ally speak+1 by ! motion ( ! m$ium relatively to u1 = a p]man5t condition c\ld n be ma9ta9$ )\t ! m$ium be+ con/antly r5ew$4 ,a vacuum _c1 accord+ to all evid5ce1 be p]man5tly ma9ta9$ ar\nd a hot body4 ,9 ^! con/ructions1 be=e m5tion$1 ! small bulb inside w\ld1 at lea/ 9 ! fir/ /ages1 prev5t all bomb>dm5t aga9/ ! out] l>ge globe4 ,x occurr$ to me !n to asc]ta9 h[ a metal sieve w\ld behave 9 ?is respect1 & sev]al bulbs1 z illu/rat$ 9 ,fig4 #aie1 7 prep>$ = ?is purpose4 ,9 a globe b1 0 m\nt$ a ?9 filam5t f 7or button7 ^u a plat9um wire w pass+ ?r\gh a glass /em & lead+ to ! outside ( ! globe4 ,! filam5t f 0 surr\nd$ by a metal sieve s4 ,x 0 f\nd 9 exp]im5ts ) su* bulbs t a sieve ) wide me%es app>5tly did n 9 ! slighte/ affect ! bomb>dm5t aga9/ ! globe b4 ,:5 ! vacuum 0 high1 ! %ad[ ( ! sieve 0 cle>ly project$ aga9/ ! globe & ! latt] w\ld get hot 9 a %ort :ile4 ,9 "s bulbs ! sieve s 0 connect$ to a plat9um wire seal$ 9 ! glass4 ,:5 ?is wire 0 connect$ to ! o!r t]m9al ( ! induction coil 7! ,e4 ,m4 ,f4 be+ kept l[ 9 ?is case71 or to an insulat$ plate1 ! bomb>dm5t aga9/ ! out] globe b 0 dim9i%$4 ,by tak+ a sieve ) f9e me%es ! bomb>dm5t aga9/ ! globe b 0 always dim9i%$1 b ev5 !n if ! exhau/ion 0 c>ri$ v f>1 & :5 ! pot5tial ( ! trans=m] 0 v high1 ! globe b w\ld be bomb>d$ & heat$ quickly1 ?\gh no %ad[ ( ! sieve 0 visible1 ow+ to ! smallness ( ! me%es4 ,b a glass tube or o!r cont9u\s body m\nt$ s z to surr\nd ! filam5t1 did entirely cut (f ! bomb>dm5t & = a :ile ! out] globe b w\ld rema9 p]fectly cold4 ,( c\rse :5 ! glass tube 0 suffici5tly heat$ ! bomb>dm5t aga9/ ! out] globe c\ld be not$ at once4 ,! exp]im5ts ) ^! bulbs seem$ to %[ t ! spe$s ( ! project$ molecules or p>ticles mu/ be consid]able 7?\gh q insignificant :5 comp>$ ) t ( light71 o!rwise x w\ld be difficult to und]/& h[ !y c\ld trav]se a f9e metal sieve )\t be+ affect$1 unless x 7 f\nd t su* small p>ticles or atoms _c be act$ ^u directly at measurable di/ances4 ,9 reg>d to ! spe$ ( ! project$ atoms1 ,"l ,kelv9 has rec5tly e/imat$ x at ab\t "o kilometre a second or !reab\ts 9 an ord9>y ,crookes bulb4 ,z ! pot5tials obta9able ) a disruptive dis*>ge coil are mu* high] ?an ) ord9>y coils1 ! spe$s mu/1 ( c\rse1 be mu* great] :5 ! bulbs are light$ f su* a coil4 ,assum+ ! spe$ to be z high z five kilometres & uni=m ?r\gh ! :ole trajectory1 z x %\ld be 9 a v highly exhau/$ vessel1 !n if ! alt]nate electrifications ( ! electrode w\ld be ( a frequ5cy ( five million1 ! greate/ di/ance a p>ticle c\ld get away f ! electrode w\ld be "o millimetre1 & if x c\ld be act$ ^u directly at t di/ance1 ! ex*ange ( electrode matt] or ( ! atoms w\ld be v sl[ & !re w\ld be practically no bomb>dm5t aga9/ ! bulb4 ,?is at lea/ %\ld be s1 if ! action ( an electrode ^u ! atoms ( ! residual gas w\ld be su* z ^u electrifi$ bodies :i* we c p]ceive4 ,a hot body enclos$ 9 an exhau/$ bulb produces always atomic bomb>dm5t1 b a hot body has no def9ite rhy?m1 = its molecules p]=m vibrations ( all k9ds4 ,if a bulb conta9+ a button or filam5t be exhau/$ z high z is possible ) ! greate/ c>e & by ! use ( ! be/ artifices1 x is (t5 obs]v$ t ! dis*>ge _c1 at fir/1 break ?r\gh1 b aft] "s "t1 probably 9 consequ5ce ( "s *anges )9 ! bulb1 ! dis*>ge f9ally passes ?r\gh & ! button is r5d]$ inc&esc5t4 ,9 fact1 x appe>s t ! high] ! degree ( exhau/ion ! easi] is ! inc&esc5ce produc$4 ,!re seem to be no o!r causes to :i* ! inc&esc5ce might be attribut$ 9 su* case except to ! bomb>dm5t or simil> action ( ! residual gas1 or ( p>ticles ( matt] 9 g5]al4 ,b if ! bulb be exhau/$ ) ! greate/ c>e c ^! play an important "p8 ,assume ! vacuum 9 ! bulb to be tol]ably p]fect1 ! great int]e/ !n c5tres 9 ! "q3 ,is ! m$ium :i* p]vades all space cont9u\s or atomic8 ,if atomic1 !n ! heat+ ( a conduct+ button or filam5t 9 an exhau/$ vessel might be due l>gely to e!r bomb>dm5t1 & !n ! heat+ ( a conductor 9 g5]al ?r\gh :i* curr5ts ( high frequ5cy or high pot5tial are pass$ mu/ be modifi$ by ! behavior ( su* m$ium2 !n also ! sk9 effect1 ! app>5t increase ( ! ohmic resi/ance1 etc41 admit1 p>tially at lea/1 ( a diff]5t explanation4 ,x is c]ta9ly m 9 accordance ) _m ph5om5a obs]v$ ) high-frequ5cy curr5ts to hold t all space is p]vad$ ) free atoms1 r ?an to assume t x is devoid ( ^!1 & d>k & cold1 = s x mu/ be1 if fill$ ) a cont9u\s m$ium1 s9ce 9 su* !re c be nei!r heat nor light4 ,is !n en]gy transmitt$ by indep5d5t c>ri]s or by ! vibration ( a cont9u\s m$ium8 ,?is important "q is by no means z yet positively answ]$4 ,b mo/ ( ! effects :i* are "h consid]$1 especially ! light effects1 inc&esc5ce1 or phosphoresc5ce1 involve ! pres5ce ( free atoms & w\ld be impossible )\t ^!4 ,9 reg>d to ! inc&esc5ce ( a refractory button 7or filam5t7 9 an exhau/$ receiv]1 :i* has be5 "o ( ! subjects ( ?is inve/igation1 ! *ief exp]i5ces1 :i* may s]ve z a guide 9 con/ruct+ su* bulbs1 may be summ$ up z foll[s3 #a4 ,! button %\ld be z small z possible1 sph]ical1 ( a smoo? or poli%$ surface1 & ( refractory mat]ial :i* )/&s evaporation be/4 #b4 ,! support ( ! button %\ld be v ?9 & scre5$ by an alum9um & mica %eet1 z ,i h describ$ on ano!r occasion4 #c4 ,! exhau/ion ( ! bulb %\ld be z high z possible4 #d4 ,! frequ5cy ( ! curr5ts %\ld be z high z practicable4 #e4 ,! curr5ts %\ld be ( a h>monic rise & fall1 )\t sudd5 int]ruptions4 #f4 ,! heat %\ld be conf9$ to ! button by inclos+ ! same 9 a small bulb or o!rwise4 #g4 ,! space betwe5 ! walls ( ! small bulb & ! out] globe %\ld be highly exhau/$4 ,mo/ ( ! consid]ations :i* apply to ! inc&esc5ce ( a solid j consid]$ may likewise be appli$ to phosphoresc5ce4 ,inde$1 9 an exhau/$ vessel ! phosphoresc5ce is1 z a rule1 prim>ily excit$ by ! p[]ful beat+ ( ! electrode /ream ( atoms aga9/ ! phosphoresc5t body4 ,ev5 9 _m cases1 :]e !re is no evid5ce ( su* a bomb>dm5t1 ,i ?9k t phosphoresc5ce is excit$ by viol5t impacts ( atoms1 :i* are n necess>ily ?r[n (f f ! electrode b are act$ ^u f ! same inductively ?r\gh ! m$ium or ?r\gh *a9s ( o!r atoms4 ,t me*anical %ocks play an important "p 9 excit+ phosphoresc5ce 9 a bulb may be se5 f ! foll[+ exp]im5t4 ,if a bulb1 con/ruct$ z t illu/rat$ 9 ,fig4 #agd1 be tak5 & exhau/$ ) ! greate/ c>e s t ! dis*>ge _c pass1 ! filam5t f acts by electro/atic induction ^u ! tube t & ! latt] is set 9 vibration4 ,if ! tube o be r wide1 ab\t an in* or s1 ! filam5t may be s p[]fully vibrat$ t :5ev] x hits ! glass tube x excites phosphoresc5ce4 ,b ! phosphoresc5ce ceases :5 ! filam5t comes to re/4 ,! vibration c be arre/$ & aga9 />t$ by v>y+ ! frequ5cy ( ! curr5ts4 ,n[ ! filam5t has its own p]iod ( vibration1 & if ! frequ5cy ( ! curr5ts is su* t !re is resonance1 x is easily set vibrat+1 ?\gh ! pot5tial ( ! curr5ts be small4 ,i h (t5 obs]v$ t ! filam5t 9 ! bulb is de/roy$ by su* me*anical resonance4 ,! filam5t vibrates z a rule s rapidly t x _c be se5 & ! exp]im5t] may at fir/ be my/ifi$4 ,:5 su* an exp]im5t z ! "o describ$ is c>efully p]=m$1 ! pot5tial ( ! curr5ts ne$ be extremely small1 & = ?is reason ,i inf] t ! phosphoresc5ce is !n due to ! me*anical %ock ( ! filam5t aga9/ ! glass1 j z x is produc$ by /rik+ a loaf ( sug> ) a knife4 ,! me*anical %ock produc$ by ! project$ atoms is easily not$ :5 a bulb conta9+ a button is grasp$ 9 ! h& & ! curr5t turn$ on sudd5ly4 ,i believe t a bulb c\ld be %att]$ by obs]v+ ! conditions ( resonance4 ,9 ! exp]im5t be=e cit$ x is1 ( c\rse1 op5 to say1 t ! glass tube1 ^u com+ 9 contact ) ! filam5t1 reta9s a *>ge ( a c]ta9 sign ^u ! po9t ( contact4 ,if n[ ! filam5t aga9 t\*es ! glass at ! same po9t :ile x is oppositely *>g$1 ! *>ges equalize "u evolution ( light4 ,b no?+ ( importance w\ld be ga9$ by su* an explanation4 ,x is unque/ionable t ! initial *>ges giv5 to ! atoms or to ! glass play "s "p 9 excit+ phosphoresc5ce4 ,s1 = in/ance1 if a phosphoresc5t bulb be fir/ excit$ by a high frequ5cy coil by connect+ x to "o ( ! t]m9als ( ! latt] & ! degree ( lum9osity be not$1 & !n ! bulb be highly *>g$ f a ,holtz ma*9e by atta*+ x pref]ably to ! positive t]m9al ( ! ma*9e1 x is f\nd t :5 ! bulb is aga9 connect$ to ! t]m9al ( ! high frequ5cy coil1 ! phosphoresc5ce is f> m int5se4 ,on ano!r occasion ,i h consid]$ ! possibility ( "s phosphoresc5t ph5om5a 9 bulbs be+ produc$ by ! inc&esc5ce ( an inf9itesimal lay] on ! surface ( ! phosphoresc5t body4 ,c]ta9ly ! impact ( ! atoms is p[]ful en\gh to produce int5se inc&esc5ce by ! collisions1 s9ce !y br+ quickly to a high temp]ature a body ( consid]able bulk4 ,if any su* effect exi/s1 !n ! be/ appliance = produc+ phosphoresc5ce 9 a bulb1 :i* we "k s f>1 is a disruptive dis*>ge coil giv+ an enorm\s pot5tial ) b few fundam5tal dis*>ges1 say #be-cj p] second1 j en\gh to produce a cont9u\s impression ^u ! eye4 ,x is a fact t su* a coil excites phosphoresc5ce "u almo/ any condition & at all degrees ( exhau/ion1 & ,i h obs]v$ effects :i* appe> to be due to phosphoresc5ce ev5 at ord9>y pressures ( ! atmosph]e1 :5 ! pot5tials are extremely high4 ,b if phosphoresc5t light is produc$ by ! equalization ( *>ges ( electrifi$ atoms 7:atev] ?is may mean ultimately71 !n ! high] ! frequ5cy ( ! impulses or alt]nate electrifications1 ! m economical w be ! light production4 ,x is a long kn[n & notewor?y fact t all ! phosphoresc5t bodies are poor conductors ( electricity & heat1 & t all bodies cease to emit phosphoresc5t light :5 !y are br\ght to a c]ta9 temp]ature4 ,conductors on ! contr>y d n possess ?is quality4 ,!re are b few exceptions to ! rule4 ,c>bon is "o ( !m4 ,becqu]el not$ t c>bon phosphoresces at a c]ta9 elevat$ temp]ature prec$+ ! d>k r$4 ,?is ph5om5on may be easily obs]v$ 9 bulbs provid$ ) a r l>ge c>bon electrode 7say1 a sph]e ( six millimetres diamet]74 ,if ! curr5t is turn$ on aft] a few seconds1 a sn[ :ite film cov]s ! electrode1 j be=e x gets d>k r$4 ,simil> effects are not$ ) o!r conduct+ bodies1 b _m sci5tific m5 w probably n attribute !m to true phosphoresc5ce4 ,:e!r true inc&esc5ce has any?+ to d ) phosphoresc5ce excit$ by atomic impact or me*anical %ocks /ill rema9s to be decid$1 b x is a fact t all conditions1 :i* t5d to localize & increase ! heat+ effect at ! po9t ( impact1 are almo/ inv>iably ! mo/ favorable = ! production ( phosphoresc5ce4 ,s1 if ! electrode be v small1 :i* is equival5t to say+ 9 g5]al1 t ! electric d5sity is great2 if ! pot5tial be high1 & if ! gas be highly r>efi$1 all ( :i* ?+s imply high spe$ ( ! project$ atoms1 or matt]1 & consequ5tly viol5t impacts--! phosphoresc5ce is v int5se4 ,if a bulb provid$ ) a l>ge & small electrode be atta*$ to ! t]m9al ( an induction coil1 ! small electrode excites phosphoresc5ce :ile ! l>ge "o may n d s1 because ( ! small] electric d5sity & h5ce small] spe$ ( ! atoms4 ,a bulb provid$ ) a l>ge electrode may be grasp$ ) ! h& :ile ! electrode is connect$ to ! t]m9al ( ! coil & x may n phosphoresce2 b if in/ead ( grasp+ ! bulb ) ! h&1 ! same be t\*$ ) a po9t$ wire1 ! phosphoresc5ce at once spreads ?r\gh ! bulb1 because ( ! great d5sity at ! po9t ( contact4 ,) l[ frequ5cies x seems t gases ( great atomic weight excite m int5se phosphoresc5ce ?an ^? ( small] weight1 z = in/ance1 hydrog54 ,) high frequ5cies ! obs]vations are n suffici5tly reliable to draw a conclusion4 ,oxyg51 z is well-kn[n1 produces exceptionally /rong effects1 :i* may be 9 "p due to *emical action4 ,a bulb ) hydrog5 residue seems to be mo/ easily excit$4 ,electrodes :i* are mo/ easily det]iorat$ produce m int5se phosphoresc5ce 9 bulbs1 b ! condition is n p]man5t because ( ! impairm5t ( ! vacuum & ! deposition ( ! electrode matt] ^u ! phosphoresc5t surfaces4 ,"s liquids1 z oils1 = in/ance1 produce magnific5t effects ( phosphoresc5ce 7or fluoresc5ce871 b !y la/ only a few seconds4 ,s if a bulb has a trace ( oil on ! walls & ! curr5t is turn$ on1 ! phosphoresc5ce only p]si/s = a few mom5ts until ! oil is c>ri$ away4 ,( all bodies s f> tri$1 sulphide ( z9c seems to be ! mo/ susceptible to phosphoresc5ce4 ,"s samples1 obta9$ ?r\gh ! k9dness ( ,pr(4 ,h5ry 9 ,p>is1 7 employ$ 9 _m ( ^! bulbs4 ,"o ( ! defects ( ?is sulphide is1 t x loses its quality ( emitt+ light :5 br\ght to a temp]ature :i* is by no means high4 ,x c !re=e1 be us$ only = feeble int5sities4 ,an obs]vation :i* might des]ve notice is1 t :5 viol5tly bomb>d$ f an alum9um electrode x assumes a black color1 b s+ul>ly en\gh1 x returns to ! orig9al condition :5 x cools d[n4 ,! mo/ important fact arriv$ at 9 pursu+ inve/igations 9 ?is direction is1 t 9 all cases x is necess>y1 9 ord] to excite phosphoresc5ce ) a m9imum am\nt ( en]gy1 to obs]ve c]ta9 conditions4 ,namely1 !re is always1 no matt] :at ! frequ5cy ( ! curr5ts1 degree ( exhau/ion & "* ( ! bodies 9 ! bulb1 a c]ta9 pot5tial 7assum+ ! bulb excit$ f "o t]m9al7 or pot5tial diff]5ce 7assum+ ! bulb to be excit$ ) bo? t]m9als7 :i* produces ! mo/ economical result4 ,if ! pot5tial be increas$1 consid]able en]gy may be wa/$ )\t produc+ any m light1 & if x be dim9i%$1 !n aga9 ! light production is n z economical4 ,! exact condition "u :i* ! be/ result is obta9$ seems to dep5d on _m ?+s ( a diff]5t nature1 & x is to be yet inve/igat$ by o!r exp]im5t]s1 b x w c]ta9ly h to be obs]v$ :5 su* phosphoresc5t bulbs are op]at$1 if ! be/ results are to be obta9$4 ,com+ n[ to ! mo/ int]e/+ ( ^! ph5om5a1 ! inc&esc5ce or phosphoresc5ce ( gases1 at l[ pressures or at ! ord9>y pressure ( ! atmosph]e1 we mu/ seek ! explanation ( ^! ph5om5a 9 ! same prim>y causes1 t is1 9 %ocks or impacts ( ! atoms4 ,j z molecules or atoms beat+ ^u a solid body excite phosphoresc5ce 9 ! same or r5d] x inc&esc5t1 s :5 collid+ among !mselves !y produce simil> ph5om5a4 ,b ?is is a v insuffici5t explanation & conc]ns only ! crude me*anism4 ,light is produc$ by vibrations :i* g on at a rate almo/ inconceivable4 ,if we compute1 f ! en]gy conta9$ 9 ! =m ( kn[n radiations 9 a def9ite space ! =ce :i* is necess>y to set up su* rapid vibrations1 we f9d1 t ?\gh ! d5sity ( ! e!r be incomp>ably small] ?an t ( any body we "k1 ev5 hydrog51 ! =ce is some?+ surpass+ compreh5sion4 ,:at is ?is =ce1 :i* 9 me*anical measure may am\nt to ?\s&s ( tons p] squ>e in*8 ,x is electro/atic =ce 9 ! light ( mod]n views4 ,x is impossible to conceive h[ a body ( measurable dim5sions c\ld be *>g$ to s high a pot5tial t ! =ce w\ld be suffici5t to produce ^! vibrations4 ,long be=e any su* *>ge c\ld be imp>t$ to ! body x w\ld be %att]$ into atoms4 ,! sun emits light & heat1 & s does an ord9>y flame or inc&esc5t filam5t1 b 9 nei!r ( ^! c ! =ce be acc\nt$ = if x be assum$ t x is associat$ ) ! body z a :ole4 ,only 9 "o way may we acc\nt = x1 namely1 by id5tify+ x ) ! atom4 ,an atom is s small1 t if x be *>g$ by com+ 9 contact ) an electrifi$ body & ! *>ge be assum$ to foll[ ! same law z 9 ! case ( bodies ( measurable dim5sions1 x mu/ reta9 a quantity ( electricity :i* is fully capable ( acc\nt+ = ^! =ces & trem5d\s rates ( vibration4 ,b ! atom behaves s+ul>ly 9 ?is respect--x always takes ! same *>ge4 ,x is v likely t resonant vibration plays a mo/ important "p 9 all manife/ations ( en]gy 9 nature4 ,?r\gh\t space all matt] is vibrat+1 & all rates ( vibration are repres5t$1 f ! l[e/ musical note to ! highe/ pit* ( ! *emical rays1 h5ce an atom1 or complex ( atoms1 no matt] :at its p]iod1 mu/ f9d a vibration ) :i* x is 9 resonance4 ,:5 we consid] ! enorm\s rapidity ( ! light vibrations1 we realize ! impossibility ( produc+ su* vibrations directly ) any app>atus ( measurable dim5sions1 & we are driv5 to ! only possible means ( atta9+ ! object ( sett+ up waves ( light by electrical means & economically1 t is1 to affect ! molecules or atoms ( a gas1 to cause !m to collide & vibrate4 ,we !n mu/ ask ourselves--,h[ c free molecules or atoms be affect$8 ,illu/ration3 ,,fig4 #aif4 ,illu/ration3 ,,fig4 #aig4 ,x is a fact t !y c be affect$ by electro/atic =ce1 z is app>5t 9 _m ( ^! exp]im5ts4 ,by v>y+ ! electro/atic =ce we c agitate ! atoms1 & cause !m to collide accompani$ by evolution ( heat & light4 ,x is n demon/rat$ beyond d\bt t we c affect !m o!rwise4 ,if a lum9\s dis*>ge is produc$ 9 a clos$ exhau/$ tube1 d ! atoms arrange !mselves 9 ob$i5ce to any o!r b to electro/atic =ce act+ 9 /raight l9es f atom to atom8 ,only rec5tly ,i inve/igat$ ! mutual action betwe5 two circuits ) extreme rates ( vibration4 ,:5 a batt]y ( a few j>s 7c c c c1 ,fig4 #aif7 is dis*>g$ ?r\gh a prim>y ,p ( l[ resi/ance 7! connections be+ z illu/rat$ 9 ,figs4 #ahc;a1 #ahc;b & #ahc;c71 & ! frequ5cy ( vibration is _m millions !re are great diff]5ces ( pot5tial betwe5 po9ts on ! prim>y n m ?an a few in*es ap>t4 ,^! diff]5ces may be #aj1jjj volts p] in*1 if n m1 tak+ ! maximum value ( ! ,e4 ,m4 ,f4 ,! second>y s is !re=e act$ ^u by electro/atic induction1 :i* is 9 su* extreme cases ( mu* great] importance ?an ! electro-dynamic4 ,to su* sudd5 impulses ! prim>y z well z ! second>y are poor conductors1 & !re=e great diff]5ces ( pot5tial may be produc$ by electro/atic induction betwe5 adjac5t po9ts on ! second>y4 ,!n sp>ks may jump betwe5 ! wires & /ream]s become visible 9 ! d>k if ! light ( ! dis*>ge ?r\gh ! sp>k gap d d be c>efully exclud$4 ,if n[ we sub/itute a clos$ vacuum tube = ! metallic second>y s1 ! diff]5ces ( pot5tial produc$ 9 ! tube by electro/atic induction f ! prim>y are fully suffici5t to excite portions ( x2 b z ! po9ts ( c]ta9 diff]5ces ( pot5tial on ! prim>y are n fix$1 b are g5]ally con/antly *ang+ 9 position1 a lum9\s b& is produc$ 9 ! tube1 app>5tly n t\*+ ! glass1 z x %\ld1 if ! po9ts ( maximum & m9imum diff]5ces ( pot5tial 7 fix$ on ! prim>y4 ,i d n exclude ! possibility ( su* a tube be+ excit$ only by electro-dynamic induction1 = v able physici/s hold ?is view2 b 9 my op9ion1 !re is z yet no positive pro( giv5 t atoms ( a gas 9 a clos$ tube may arrange !mselves 9 *a9s "u ! action ( an electromotive impulse produc$ by electro-dynamic induction 9 ! tube4 ,i h be5 unable s f> to produce /riae 9 a tube1 h[ev] long1 & at :atev] degree ( exhau/ion1 t is1 /riae at "r angles to ! suppos$ direction ( ! dis*>ge or ! axis ( ! tube2 b ,i h di/9ctly obs]v$ 9 a l>ge bulb1 9 :i* a wide lum9\s b& 0 produc$ by pass+ a dis*>ge ( a batt]y ?r\gh a wire surr\nd+ ! bulb1 a circle ( feeble lum9osity betwe5 two lum9\s b&s1 "o ( :i* 0 m int5se ?an ! o!r4 ,fur!rmore1 ) my pres5t exp]i5ce ,i d n ?9k t su* a gas dis*>ge 9 a clos$ tube c vibrate1 t is1 vibrate z a :ole4 ,i am conv9c$ t no dis*>ge ?r\gh a gas c vibrate4 ,! atoms ( a gas behave v curi\sly 9 respect to sudd5 electric impulses4 ,! gas does n seem to possess any appreciable in]tia to su* impulses1 = x is a fact1 t ! high] ! frequ5cy ( ! impulses1 ) ! great] fre$om does ! dis*>ge pass ?r\gh ! gas4 ,if ! gas possesses no in]tia !n x _c vibrate1 = "s in]tia is necess>y = ! free vibration4 ,i conclude f ?is t if a lightn+ dis*>ge occurs betwe5 two cl\ds1 !re c be no oscillation1 su* z w\ld be expect$1 consid]+ ! capacity ( ! cl\ds4 ,b if ! lightn+ dis*>ge /rike ! e>?1 !re is always vibration--9 ! e>?1 b n 9 ! cl\d4 ,9 a gas dis*>ge ea* atom vibrates at its own rate1 b !re is no vibration ( ! conduct+ gase\s mass z a :ole4 ,?is is an important consid]ation 9 ! great problem ( produc+ light economically1 = x tea*es u t to rea* ?is result we mu/ use impulses ( v high frequ5cy & necess>ily also ( high pot5tial4 ,x is a fact t oxyg5 produces a m int5se light 9 a tube4 ,is x because oxyg5 atoms possess "s in]tia & ! vibration does n die out in/antly8 ,b !n nitrog5 %\ld be z good1 & *lor9e & vapors ( _m o!r bodies mu* bett] ?an oxyg51 unless ! magnetic prop]ties ( ! latt] ent] prom95tly into play4 ,or1 is ! process 9 ! tube ( an electrolytic nature8 ,_m obs]vations c]ta9ly speak = x1 ! mo/ important be+ t matt] is always c>ri$ away f ! electrodes & ! vacuum 9 a bulb _c be p]man5tly ma9ta9$4 ,if su* process takes place 9 reality1 !n aga9 mu/ we take refuge 9 high frequ5cies1 =1 ) su*1 electrolytic action %\ld be r$uc$ to a m9imum1 if n r5d]$ entirely impossible4 ,x is an und5iable fact t ) v high frequ5cies1 provid$ ! impulses be ( h>monic nature1 l ^? obta9$ f an alt]nator1 !re is less det]ioration & ! vacua are m p]man5t4 ,) disruptive dis*>ge coils !re are sudd5 rises ( pot5tial & ! vacua are m quickly impair$1 = ! electrodes are det]iorat$ 9 a v %ort "t4 ,x 0 obs]v$ 9 "s l>ge tubes1 :i* 7 provid$ ) heavy c>bon blocks ,b ,b#a1 connect$ to plat9um wires w w#a 7z illu/rat$ 9 ,fig4 #aig71 & :i* 7 employ$ 9 exp]im5ts ) ! disruptive dis*>ge in/ead ( ! ord9>y air gap1 t ! c>bon p>ticles "u ! action ( ! p[]ful magnetic field 9 :i* ! tube 0 plac$1 7 deposit$ 9 regul> f9e l9es 9 ! middle ( ! tube1 z illu/rat$4 ,^! l9es 7 attribut$ to ! deflection or di/ortion ( ! dis*>ge by ! magnetic field1 b :y ! deposit occurr$ pr9cipally :]e ! field 0 mo/ int5se did n appe> q cle>4 ,a fact ( int]e/1 likewise not$1 0 t ! pres5ce ( a /rong magnetic field increases ! det]ioration ( ! electrodes1 probably by reason ( ! rapid int]ruptions x produces1 :]eby !re is actually a high] ,e4 ,m4 ,f4 ma9ta9$ betwe5 ! electrodes4 ,mu* w\ld rema9 to be said ab\t ! lum9\s effects produc$ 9 gases at l[ or ord9>y pressures4 ,) ! pres5t exp]i5ces be=e u we _c say t ! ess5tial nature ( ^! *>m+ ph5om5a is suffici5tly kn[n4 ,b inve/igations 9 ?is direction are be+ pu%$ ) exceptional ardor4 ,e l9e ( sci5tific pursuit has its fasc9ations1 b electrical inve/igation appe>s to possess a peculi> attraction1 = !re is no exp]im5t or obs]vation ( any k9d 9 ! doma9 ( ?is wond]ful sci5ce :i* w\ld n =cibly appeal to u4 ,yet to me x seems1 t ( all ! _m m>vel\s ?+s we obs]ve1 a vacuum tube1 excit$ by an electric impulse f a di/ant s\rce1 bur/+ =? out ( ! d>kness & illum9at+ ! room ) its beautiful light1 is z lovely a ph5om5on z c greet our eyes4 ,m int]e/+ /ill x appe>s :51 r$uc+ ! fundam5tal dis*>ges across ! gap to a v small numb] & wav+ ! tube ab\t we produce all k9ds ( designs 9 lum9\s l9es4 ,s by way ( amusem5t ,i take a /raight long tube1 or a squ>e "o1 or a squ>e atta*$ to a /raight tube1 & by :irl+ !m ab\t 9 ! h&1 ,i imitate ! spokes ( a :eel1 a ,gramme w9d+1 a drum w9d+1 an alt]nate curr5t motor w9d+1 etc4 7,fig4 #aih74 ,view$ f a di/ance ! effect is weak & mu* ( its beauty is lo/1 b be+ ne> or hold+ ! tube 9 ! h&1 "o _c resi/ its *>m4 ,illu/ration3 ,,fig4 #aih4 ,9 pres5t+ ^! insignificant results ,i h n attempt$ to arrange & co-ord9ate !m1 z w\ld be prop] 9 a /rictly sci5tific inve/igation1 9 :i* e succe$+ result %\ld be a logical sequ5ce ( ! prec$+1 s t x might be guess$ 9 advance by ! c>eful read] or att5tive li/5]4 ,i h pref]r$ to conc5trate my en]gies *iefly ^u advanc+ novel facts or ideas :i* might s]ve z sugge/ions to o!rs1 & ?is may s]ve z an excuse = ! lack ( h>mony4 ,! explanations ( ! ph5om5a h be5 giv5 9 good fai? & 9 ! _s ( a /ud5t prep>$ to f9d t !y admit ( a bett] int]pretation4 ,!re c be no great h>m 9 a /ud5t tak+ an errone\s view1 b :5 great m9ds err1 ! _w mu/ de>ly pay = _! mi/akes4 ,,*apt] ,,xxix4 ,,tesla ,,alt]nat+ ,,curr5t ,,g5]ators ,,= ,,high ,,frequ5cy1 ,,9 ,,detail4 ,x has become a common practice to op]ate arc lamps by alt]nat+ or pulsat+1 z di/+ui%$ f cont9u\s1 curr5ts2 b an objection :i* has be5 rais$ to su* sy/ems exi/s 9 ! fact t ! arcs emit a pron\nc$ s\nd1 v>y+ ) ! rate ( ! alt]nations or pulsations ( curr5t4 ,?is noise is due to ! rapidly alt]nat+ heat+ & cool+1 & consequ5t expansion & contraction1 ( ! gase\s matt] =m+ ! arc1 :i* corresponds ) ! p]iods or impulses ( ! curr5t4 ,ano!r disadvantage\s feature is f\nd 9 ! difficulty ( ma9ta9+ an alt]nat+ curr5t arc 9 consequ5ce ( ! p]iodical increase 9 resi/ance correspond+ to ! p]iodical work+ ( ! curr5t4 ,?is feature entails a fur!r disadvantage1 namely1 t small arcs are impracticable4 ,!oretical consid]ations h l$ ,mr4 ,tesla to ! belief t ^! disadvantage\s features c\ld be obviat$ by employ+ curr5ts ( a suffici5tly high numb] ( alt]nations1 & 8 anticipations h be5 confirm$ 9 practice4 ,^! rapidly alt]nat+ curr5ts r5d] x possible to ma9ta9 small arcs :i*1 besides1 possess ! advantages ( sil5ce & p]si/5cy4 ,! latt] quality is due to ! necess>ily rapid alt]nations1 9 consequ5ce ( :i* ! arc has no "t to cool1 & is always ma9ta9$ at a high temp]ature & l[ resi/ance4 ,at ! outset ( 8 exp]im5ts ,mr4 ,tesla enc\nt]$ great difficulties 9 ! con/ruction ( high frequ5cy ma*9es4 ,a g5]ator ( ?is k9d is describ$ "h1 :i*1 ?\gh con/ruct$ q "s "t ago1 is well wor?y ( a detail$ description4 ,x may be m5tion$1 9 pass+1 t dynamos ( ?is type h be5 us$ by ,mr4 ,tesla 9 8 light+ rese>*es & exp]im5ts ) curr5ts ( high pot5tial & high frequ5cy1 & ref]5ce to !m w be f\nd 9 8 lectures else:]e pr9t$ 9 ?is volume4#d #d ,see pages #aec-d #e4 ,9 ! accompany+ engrav+s1 ,figs4 #aii & #bjj %[ ! ma*9e1 respectively1 9 side elevation & v]tical cross-section2 ,figs4 #bja1 #bjb & #bjc %[+ enl>g$ details ( con/ruction4 ,z w be se51 ,a is an annul> magnetic frame1 ! int]ior ( :i* is provid$ ) a l>ge numb] ( pole-pieces ,d4 ,ow+ to ! v l>ge numb] & small size ( ! poles & ! spaces betwe5 !m1 ! field coils are appli$ by w9d+ an insulat$ conductor ,f zigzag ?r\gh ! grooves1 z %[n 9 ,fig4 #bjc1 c>ry+ ! wire ar\nd ! annulus to =m z _m lay]s z is desir$4 ,9 ?is way ! pole-pieces ,d w be en]giz$ ) alt]nately opposite pol>ity ar\nd ! entire r+4 ,= ! armature1 ,mr4 ,tesla employs a spid] c>ry+ a r+ ,j1 turn$ d[n1 except at its edges1 to =m a tr\gh-l receptacle = a mass ( f9e anneal$ iron wires ,k1 :i* are w\nd 9 ! groove to =m ! core prop] = ! armature-coils4 ,p9s ,l are set 9 ! sides ( ! r+ ,j & ! coils ,m are w\nd ov] ! p]iph]y ( ! armature-/ructure & ar\nd ! p9s4 ,! coils ,m are connect$ toge!r 9 s]ies1 & ^! t]m9als ,n c>ri$ ?r\gh ! holl[ %aft ,h to contact-r+s ,p ,p1 f :i* ! curr5ts are tak5 (f by bru%es ,o4 ,illu/ration3 ,,fig4 #aii4 ,9 ?is way a ma*9e ) a v l>ge numb] ( poles may be con/ruct$4 ,x is easy1 = in/ance1 to obta9 9 ?is mann] ?ree hundr$ & sev5ty-five to f\r hundr$ poles 9 a ma*9e t may be safely driv5 at a spe$ ( fifte5 hundr$ or sixte5 hundr$ revolutions p] m9ute1 :i* w produce t5 ?\s& or elev5 ?\s& alt]nations ( curr5t p] second4 ,arc lamps ,r ,r are %[n 9 ! diagram z connect$ up 9 s]ies ) ! ma*9e 9 ,fig4 #bjj4 ,if su* a curr5t be appli$ to runn+ arc lamps1 ! s\nd produc$ by or 9 ! arc becomes practically inaudible1 =1 by increas+ ! rate ( *ange 9 ! curr5t1 & consequ5tly ! numb] ( vibrations p] unit ( "t ( ! gase\s mat]ial ( ! arc up to1 or beyond1 t5 ?\s& or elev5 ?\s& p] second1 or to :at is reg>d$ z ! limit ( audition1 ! s\nd due to su* vibrations w n be audible4 ,! exact numb] ( *anges or undulations necess>y to produce ?is result w v>y some:at accord+ to ! size ( ! arc--t is to say1 ! small] ! arc1 ! great] ! numb] ( *anges t w be requir$ to r5d] x inaudible )9 c]ta9 limits4 ,x %\ld also be /at$ t ! arc %\ld n exce$ a c]ta9 l5g?4 ,illu/ration3 ,,figs4 #bjj1 #bja1 #bjb & #bjc4 ,! difficulties enc\nt]$ 9 ! con/ruction ( ^! ma*9es are ( a me*anical z well z an electrical nature4 ,! ma*9es may be design$ on two plans3 ! field may be =m$ ei!r ( alt]nat+ poles1 or ( pol> projections ( ! same pol>ity4 ,up to ab\t #ae1jjj alt]nations p] second 9 an exp]im5tal ma*9e1 ! =m] plan may be foll[$1 b a m effici5t ma*9e is obta9$ on ! second plan4 ,9 ! ma*9e above describ$1 :i* 0 capable ( runn+ two arcs ( normal c&le p[]1 ! field 0 compos$ ( a r+ ( wr\ght iron #cb in*es outside diamet]1 & ab\t #a in* ?ick4 ,! inside diamet] 0 #cj in*es4 ,!re 7 #chd pol> projections4 ,! wire 0 w\nd 9 zigzag =m1 b two wires 7 w\nd s z to completely envelop ! projections4 ,! di/ance betwe5 ! projections is ab\t #c_/af in*1 & !y are a little ov] #a_/af in* ?ick4 ,! field magnet 0 made relatively small s z to adapt ! ma*9e = a con/ant curr5t4 ,!re are #chd coils connect$ 9 two s]ies4 ,x 0 f\nd impracticable to use any wire mu* ?ick] ?an ,no4 #bf ,b4 & ,s4 gauge on acc\nt ( ! local effects4 ,9 su* a ma*9e ! cle>ance %\ld be z small z possible2 = ?is reason ! ma*9e 0 made only #a-a_/d in* wide1 s t ! b9d+ wires might be obviat$4 ,! armature wires mu/ be w\nd ) great c>e1 z !y are apt to fly (f 9 consequ5ce ( ! great p]iph]al spe$4 ,9 v>i\s exp]im5ts ?is ma*9e has be5 run z high z #c1jjj revolutions p] m9ute4 ,ow+ to ! great spe$ x 0 possible to obta9 z high z #aj amp]es out ( ! ma*9e4 ,! electromotive =ce 0 regulat$ by means ( an adju/able cond5s] )9 v wide limits1 ! limits be+ ! great]1 ! great] ! spe$4 ,?is ma*9e 0 frequ5tly us$ to run ,mr4 ,tesla's laboratory lights4 ,illu/ration3 ,,fig4 #bjd4 ,! ma*9e above describ$ 0 only "o ( _m su* types con/ruct$4 ,x s]ves well = an exp]im5tal ma*9e1 b if /ill high] alt]nations are requir$ & high] effici5cy is necess>y1 !n a ma*9e on a plan %[n 9 ,figs4 #bjd to #bjg1 is pref]able4 ,! pr9cipal advantage ( ?is type ( ma*9e is t !re is n mu* magnetic leakage1 & t a field may be produc$1 v>y+ greatly 9 int5sity 9 places n mu* di/ant f ea* o!r4 ,9 ^! engrav+s1 ,figs4 #bjd & #bje illu/rate a ma*9e 9 :i* ! armature conductor & field coils are /ation>y1 :ile ! field magnet core revolves4 ,fig4 #bjf %[s a ma*9e embody+ ! same plan ( con/ruction1 b hav+ a /ation>y field magnet & rot>y armature4 ,! conductor 9 :i* ! curr5ts are induc$ may be arrang$ 9 v>i\s ways2 b ,mr4 ,tesla pref]s ! foll[+ me?od3 ,he employs an annul> plate ( copp] ,d1 & by means ( a saw cuts 9 x radial slots f "o edge ne>ly ?r\gh to ! o!r1 beg9n+ alt]nately f opposite edges4 ,9 ?is way a cont9u\s zigzag conductor is =m$4 ,:5 ! pol> projections are #a_/h in* wide1 ! wid? ( ! conductor %\ld n1 "u any circum/ances1 be m ?an #a_/cb in* wide2 ev5 !n ! eddy effect is consid]able4 ,illu/ration3 ,,fig4 #bje4 ,to ! inn] edge ( ?is plate are secur$ two r+s ( non-magnetic metal ,e1 :i* are insulat$ f ! copp] conductor1 b held firmly !reto by means ( ! bolts ,f4 ,)9 ! r+s ,e is !n plac$ an annul> coil ,g1 :i* is ! en]giz+ coil = ! field magnet4 ,! conductor ,d & ! p>ts atta*$ !reto are support$ by means ( ! cyl9drical %ell or ca/+ ,a ,a1 ! two p>ts ( :i* are br\ght toge!r & clamp$ to ! out] edge ( ! conductor ,d4 ,illu/ration3 ,,fig4 #bjf4 ,! core = ! field magnet is built up ( two circul> p>ts ,h ,h1 =m$ ) annul> grooves ,i1 :i*1 :5 ! two p>ts are br\ght toge!r1 =m a space = ! reception ( ! en]giz+ coil ,g4 ,! hubs ( ! cores are tru$ (f1 s z to fit closely aga9/ "o ano!r1 :ile ! out] portions or flanges :i* =m ! pol> faces ,j ,j1 are r$uc$ some:at 9 ?ickness to make room = ! conductor ,d1 & are s]rat$ on _! faces4 ,! numb] ( s]rations 9 ! pol> faces is arbitr>y2 b !re mu/ exi/ betwe5 !m & ! radial portions ( ! conductor ,d c]ta9 relation1 :i* w be und]/ood by ref]5ce to ,fig4 #bjg 9 :i* ,n ,n repres5t ! projections or po9ts on "o face ( ! core ( ! field1 & ,s ,s ! po9ts ( ! o!r face4 ,! conductor ,d is %[n 9 ?is figure 9 section a a' designat+ ! radial portions ( ! conductor1 & b ! insulat+ divisions betwe5 !m4 ,! relative wid? ( ! p>ts a a' & ! space betwe5 any two adjac5t po9ts ,n ,n or ,s ,s is su* t :5 ! radial portions a ( ! conductor are pass+ betwe5 ! opposite po9ts ,n ,s :]e ! field is /ronge/1 ! int]m$iate radial portions a' are pass+ ?r\gh ! wide/ spaces midway betwe5 su* po9ts & :]e ! field is weake/4 ,s9ce ! core on "o side is ( opposite pol>ity to ! "p fac+ x1 all ! projections ( "o pol> face w be ( opposite pol>ity to ^? ( ! o!r face4 ,h5ce1 al?\gh ! space betwe5 any two adjac5t po9ts on ! same face may be extremely small1 !re w be no leakage ( ! magnetic l9es betwe5 any two po9ts ( ! same "n1 b ! l9es ( =ce w pass across f "o set ( po9ts to ! o!r4 ,! con/ruction foll[$ obviates to a great degree ! di/ortion ( ! magnetic l9es by ! action ( ! curr5t 9 ! conductor ,d1 9 :i* x w be obs]v$ ! curr5t is fl[+ at any giv5 "t f ! c5tre t[>d ! p]iph]y 9 "o set ( radial p>ts a & 9 ! opposite direction 9 ! adjac5t p>ts a'4 ,9 ord] to connect ! en]giz+ coil ,g1 ,fig4 #bjd1 ) a s\rce ( cont9u\s curr5t1 ,mr4 ,tesla utilizes two adjac5t radial portions ( ! conductor ,d = connect+ ! t]m9als ( ! coil ,g ) two b9d+ po/s ,m4 ,= ?is purpose ! plate ,d is cut entirely ?r\gh1 z %[n1 & ! break ?us made is bridg$ ov] by a %ort conductor ,c4 ,! plate ,d is cut ?r\gh to =m two t]m9als d1 :i* are connect$ to b9d+ po/s ,n4 ,! core ,h ,h1 :5 rotat$ by ! driv+ pulley1 g5]ates 9 ! conductors ,d an alt]nat+ curr5t1 :i* is tak5 (f f ! b9d+ po/s ,n4 ,illu/ration3 ,,fig4 #bjg4 ,:5 x is desir$ to rotate ! conductor betwe5 ! faces ( a /ation>y field magnet1 ! con/ruction %[n 9 ,fig4 #bjf1 is adopt$4 ,! conductor ,d 9 ?is case is or may be made 9 sub/antially ! same mann] z above describ$ by slott+ an annul> conduct+-plate & support+ x betwe5 two heads ,o1 held toge!r by bolts o & fix$ to ! driv+-%aft ,k4 ,! inn] edge ( ! plate or conductor ,d is pref]ably flang$ to secure a firm] union betwe5 x & ! heads ,o4 ,x is insulat$ f ! head4 ,! field-magnet 9 ?is case consi/s ( two annul> p>ts ,h ,h1 provid$ ) annul> grooves ,i = ! reception ( ! coils4 ,! flanges or faces surr\nd+ ! annul> groove are br\ght toge!r1 :ile ! inn] flanges are s]rat$1 z 9 ! previ\s case1 & =m ! pol> faces4 ,! two p>ts ,h ,h are =m$ ) a base ,r1 ^u :i* ! ma*9e re/s4 ,s ,s are non-magnetic bu%+s secur$ or set 9 ! c5tral op5+ ( ! cores4 ,! conductor ,d is cut entirely ?r\gh at "o po9t to =m t]m9als1 f :i* insulat$ conductors ,t are l$ ?r\gh ! %aft to collect+-r+s ,v4 ,9 "o type ( ma*9e ( ?is k9d con/ruct$ by ,mr4 ,tesla1 ! field _h #dhj pol> projections on ea* side1 & f ?is ma*9e x 0 possible to obta9 #cj1jjj alt]nations p] second4 ,z ! pol> projections mu/ necess>ily be v n>r[1 v ?9 wires or %eets mu/ be us$ to avoid ! eddy curr5t effects4 ,mr4 ,tesla has ?us con/ruct$ ma*9es ) a /ation>y armature & rotat+ field1 9 :i* case also ! field-coil 0 support$ s t ! revolv+ "p consi/$ only ( a wr\ght iron body devoid ( any wire & also ma*9es ) a rotat+ armature & /ation>y field4 ,! ma*9es may be ei!r drum or disc1 b ,mr4 ,tesla's exp]i5ce %[s ! latt] to be pref]able4 99 99 99 99 99 ,9 ! c\rse ( a v int]e/+ article contribut$ to ! ,electrical ,_w 9 ,febru>y1 #ahia1 ,mr4 ,tesla makes "s sugge/ive rem>ks on ^! high frequ5cy ma*9es & 8 exp]i5ces ) !m1 z well z ) o!r p>ts ( ! high frequ5cy app>atus4 ,"p ( x is quot$ "h & is z foll[s3-- ,! writ] w incid5tally m5tion t any "o :o attempts = ! fir/ "t to con/ruct su* a ma*9e w h a tale ( woe to tell4 ,he w fir/ />t out1 z a matt] ( c\rse1 by mak+ an armature ) ! requir$ numb] ( pol> projections4 ,he w !n get ! satisfaction ( hav+ produc$ an app>atus :i* is fit to accompany a ?or\ghly ,wagn]ian op]a4 ,x may besides possess ! virtue ( conv]t+ me*anical en]gy into heat 9 a ne>ly p]fect mann]4 ,if !re is a rev]sal 9 ! pol>ity ( ! projections1 he w get heat out ( ! ma*9e2 if !re is no rev]sal1 ! heat+ w be less1 b ! output w be next to no?+4 ,he w !n ab&on ! iron 9 ! armature1 & he w get f ! ,scylla to ! ,*>ybdis4 ,he w look = "o difficulty & w f9d ano!r1 b1 aft] a few trials1 he may get ne>ly :at he want$4 ,among ! _m exp]im5ts :i* may be p]=m$ ) su* a ma*9e1 ( n ! lea/ int]e/ are ^? p]=m$ ) a high-t5sion induction coil4 ,! "* ( ! dis*>ge is completely *ang$4 ,! arc is e/abli%$ at mu* great] di/ances1 & x is s easily affect$ by ! slighte/ curr5t ( air t x (t5 wriggles ar\nd 9 ! mo/ s+ul> mann]4 ,x usually emits ! rhy?mical s\nd peculi> to ! alt]nate curr5t arcs1 b ! curi\s po9t is t ! s\nd may be he>d ) a numb] ( alt]nations f> above t5 ?\s& p] second1 :i* by _m is consid]$ to be ab\t ! limit ( audition4 ,9 _m respects ! coil behaves l a /atic ma*9e4 ,po9ts impair consid]ably ! sp>k+ int]val1 electricity escap+ f !m freely1 & f a wire atta*$ to "o ( ! t]m9als /reams ( light issue1 z ?\gh x 7 connect$ to a pole ( a p[]ful ,toepl] ma*9e4 ,all ^! ph5om5a are1 ( c\rse1 mo/ly due to ! enorm\s diff]5ces ( pot5tial obta9$4 ,z a consequ5ce ( ! self-induction ( ! coil & ! high frequ5cy1 ! curr5t is m9ute :ile !re is a correspond+ rise ( pressure4 ,a curr5t impulse ( "s /r5g? />t$ 9 su* a coil %\ld p]si/ to fl[ no less ?an f\r t5-?\s&?s ( a second4 ,z ?is "t is great] ?an half ! p]iod1 x occurs t an oppos+ electromotive =ce beg9s to act :ile ! curr5t is /ill fl[+4 ,z a consequ5ce1 ! pressure rises z 9 a tube fill$ ) liquid & vibrat$ rapidly ar\nd its axis4 ,! curr5t is s small t1 9 ! op9ion & involunt>y exp]i5ce ( ! writ]1 ! dis*>ge ( ev5 a v l>ge coil _c produce s]i\sly injuri\s effects1 :]eas1 if ! same coil 7 op]at$ ) a curr5t ( l[] frequ5cy1 ?\gh ! electromotive =ce w\ld be mu* small]1 ! dis*>ge w\ld be mo/ c]ta9ly injuri\s4 ,?is result1 h[ev]1 is due 9 "p to ! high frequ5cy4 ,! writ]'s exp]i5ces t5d to %[ t ! high] ! frequ5cy ! great] ! am\nt ( electrical en]gy :i* may be pass$ ?r\gh ! body )\t s]i\s discom=t2 :5ce x seems c]ta9 t human tissues act z cond5s]s4 ,"o is n q prep>$ = ! behavior ( ! coil :5 connect$ to a ,leyd5 j>4 ,"o1 ( c\rse1 anticipates t s9ce ! frequ5cy is high ! capacity ( ! j> %\ld be small4 ,he !re=e takes a v small j>1 ab\t ! size ( a small w9e glass1 b he f9ds t ev5 ) ?is j> ! coil is practically %ort-circuit$4 ,he !n r$uces ! capacity until he comes to ab\t ! capacity ( two sph]es1 say1 t5 c5timetres 9 diamet] & two to f\r c5timetres ap>t4 ,! dis*>ge !n assumes ! =m ( a s]rat$ b& exactly l a succession ( sp>ks view$ 9 a rapidly revolv+ mirror2 ! s]rations1 ( c\rse1 correspond+ to ! cond5s] dis*>ges4 ,9 ?is case "o may obs]ve a que] ph5om5on4 ,! dis*>ge />ts at ! ne>e/ po9ts1 works gradually up1 breaks some:]e ne> ! top ( ! sph]es1 beg9s aga9 at ! bottom1 & s on4 ,?is goes on s fa/ t sev]al s]rat$ b&s are se5 at once4 ,"o may be puzzl$ = a few m9utes1 b ! explanation is simple en\gh4 ,! dis*>ge beg9s at ! ne>e/ po9ts1 ! air is heat$ & c>ries ! arc upw>d until x breaks1 :5 x is re-e/abli%$ at ! ne>e/ po9ts1 etc4 ,s9ce ! curr5t passes easily ?r\gh a cond5s] ( ev5 small capacity1 x w be f\nd q natural t connect+ only "o t]m9al to a body ( ! same size1 no matt] h[ well insulat$1 impairs consid]ably ! /rik+ di/ance ( ! arc4 ,exp]im5ts ) ,geissl] tubes are ( special int]e/4 ,an exhau/$ tube1 devoid ( electrodes ( any k9d1 w light up at "s di/ance f ! coil4 ,if a tube f a vacuum pump is ne> ! coil ! :ole ( ! pump is brilliantly light$4 ,an inc&esc5t lamp approa*$ to ! coil lights up & gets p]ceptibly hot4 ,if a lamp h ! t]m9als connect$ to "o ( ! b9d+ po/s ( ! coil & ! h& is approa*$ to ! bulb1 a v curi\s & r unpleasant dis*>ge f ! glass to ! h& takes place1 & ! filam5t may become inc&esc5t4 ,! dis*>ge resembles to "s ext5t ! /ream issu+ f ! plates ( a p[]ful ,toepl] ma*9e1 b is ( incomp>ably great] quantity4 ,! lamp 9 ?is case acts z a cond5s]1 ! r>efi$ gas be+ "o coat+1 ! op]ator's h& ! o!r4 ,by tak+ ! globe ( a lamp 9 ! h&1 & by br++ ! metallic t]m9als ne> to or 9 contact ) a conductor connect$ to ! coil1 ! c>bon is br\ght to bright inc&esc5ce & ! glass is rapidly heat$4 ,) a #ajj-volt #aj ,c4 ,p4 lamp "o may )\t great discom=t /& z mu* curr5t z w br+ ! lamp to a consid]able brilliancy2 b x c be held 9 ! h& only = a few m9utes1 z ! glass is heat$ 9 an incr$ibly %ort "t4 ,:5 a tube is light$ by br++ x ne> to ! coil x may be made to g out by int]pos+ a metal plate on ! h& betwe5 ! coil & tube2 b if ! metal plate be fa/5$ to a glass rod or o!rwise insulat$1 ! tube may rema9 light$ if ! plate be int]pos$1 or may ev5 increase 9 lum9osity4 ,! effect dep5ds on ! position ( ! plate & tube relatively to ! coil1 & may be always easily =etold by assum+ t conduction takes place f "o t]m9al ( ! coil to ! o!r4 ,accord+ to ! position ( ! plate1 x may ei!r div]t f or direct ! curr5t to ! tube4 ,9 ano!r l9e ( "w ! writ] has 9 frequ5t exp]im5ts ma9ta9$ inc&esc5t lamps ( #ej or #ajj volts burn+ at any desir$ c&le p[] ) bo? ! t]m9als ( ea* lamp connect$ to a /\t copp] wire ( no m ?an a few feet 9 l5g?4 ,^! exp]im5ts seem int]e/+ en\gh1 b !y are n m s ?an ! que] exp]im5t ( ,f>aday1 :i* has be5 reviv$ & made mu* ( by rec5t inve/igators1 & 9 :i* a dis*>ge is made to jump betwe5 two po9ts ( a b5t copp] wire4 ,an exp]im5t may be cit$ "h :i* may seem equally int]e/+4 ,if a ,geissl] tube1 ! t]m9als ( :i* are jo9$ by a copp] wire1 be approa*$ to ! coil1 c]ta9ly no "o w\ld be prep>$ to see ! tube light up4 ,curi\sly en\gh1 x does light up1 &1 :at is m1 ! wire does n seem to make mu* diff]5ce4 ,n[ "o is apt to ?9k 9 ! fir/ mom5t t ! imp$ance ( ! wire might h some?+ to d ) ! ph5om5on4 ,b ?is is ( c\rse imm$iately reject$1 z = ?is an enorm\s frequ5cy w\ld be requir$4 ,?is result1 h[ev]1 seems puzzl+ only at fir/2 = ^u reflection x is q cle> t ! wire c make b little diff]5ce4 ,x may be expla9$ 9 m ?an "o way1 b x agrees p]haps be/ ) obs]vation to assume t conduction takes place f ! t]m9als ( ! coil ?r\gh ! space4 ,on ?is assumption1 if ! tube ) ! wire be held 9 any position1 ! wire c div]t little m ?an ! curr5t :i* passes ?r\gh ! space occupi$ by ! wire & ! metallic t]m9als ( ! tube2 ?r\gh ! adjac5t space ! curr5t passes practically undi/urb$4 ,= ?is reason1 if ! tube be held 9 any position at "r angles to ! l9e jo9+ ! b9d+ po/s ( ! coil1 ! wire makes h>dly any diff]5ce1 b 9 a position m or less p>allel ) t l9e x impairs to a c]ta9 ext5t ! brilliancy ( ! tube & its facility to light up4 ,num]\s o!r ph5om5a may be expla9$ on ! same assumption4 ,= in/ance1 if ! ends ( ! tube be provid$ ) wa%]s ( suffici5t size & held 9 ! l9e jo9+ ! t]m9als ( ! coil1 x w n light up1 & !n ne>ly ! :ole ( ! curr5t1 :i* w\ld o!rwise pass uni=mly ?r\gh ! space betwe5 ! wa%]s1 is div]t$ ?r\gh ! wire4 ,b if ! tube be incl9$ suffici5tly to t l9e1 x w light up 9 spite ( ! wa%]s4 ,also1 if a metal plate be fa/5$ ^u a glass rod & held at "r angles to ! l9e jo9+ ! b9d+ po/s1 & ne>] to "o ( !m1 a tube held m or less p>allel ) ! l9e w light up in/antly :5 "o ( ! t]m9als t\*es ! plate1 & w g out :5 sep>at$ f ! plate4 ,! great] ! surface ( ! plate1 up to a c]ta9 limit1 ! easi] ! tube w light up4 ,:5 a tube is plac$ at "r angles to ! /raight l9e jo9+ ! b9d+ po/s1 & !n rotat$1 its lum9osity /eadily increases until x is p>allel ) t l9e4 ,! writ] mu/ /ate1 h[ev]1 t he does n favor ! idea ( a leakage or curr5t ?r\gh ! space any m ?an z a suitable explanation1 = he is conv9c$ t all ^! exp]im5ts c\ld n be p]=m$ ) a /atic ma*9e yield+ a con/ant diff]5ce ( pot5tial1 & t cond5s] action is l>gely conc]n$ 9 ^! ph5om5a4 ,x is well to take c]ta9 precautions :5 op]at+ a ,ruhmkorff coil ) v rapidly alt]nat+ curr5ts4 ,! prim>y curr5t %\ld n be turn$ on too long1 else ! core may get s hot z to melt ! gutta-p]*a or p>aff91 or o!rwise injure ! insulation1 & ?is may occur 9 a surpris+ly %ort "t1 consid]+ ! curr5t's /r5g?4 ,! prim>y curr5t be+ turn$ on1 ! f9e wire t]m9als may be jo9$ )\t great risk1 ! imp$ance be+ s great t x is difficult to =ce en\gh curr5t ?r\gh ! f9e wire s z to injure x1 & 9 fact ! coil may be on ! :ole mu* saf] :5 ! t]m9als ( ! f9e wire are connect$ ?an :5 !y are insulat$2 b special c>e %\ld be tak5 :5 ! t]m9als are connect$ to ! coat+s ( a ,leyd5 j>1 = ) any:]e ne> ! critical capacity1 :i* j c\nt]acts ! self-induction at ! exi/+ frequ5cy1 ! coil might meet ! fate ( ,/4 ,polyc>pus4 ,if an exp5sive vacuum pump is light$ up by be+ ne> to ! coil or t\*$ ) a wire connect$ to "o ( ! t]m9als1 ! curr5t %\ld be left on no m ?an a few mom5ts1 else ! glass w be crack$ by ! heat+ ( ! r>efi$ gas 9 "o ( ! n>r[ passages--9 ! writ]'s own exp]i5ce quod erat demon/r&um4#e #e ,x is ?\ght necess>y to rem>k t1 al?\gh ! induction coil may give q a good result :5 op]at$ ) su* rapidly alt]nat+ curr5ts1 yet its con/ruction1 q irrespective ( ! iron core1 makes x v unfit = su* high frequ5cies1 & to obta9 ! be/ results ! con/ruction %\ld be greatly modifi$4 ,!re are a good _m o!r po9ts ( int]e/ :i* may be obs]v$ 9 connection ) su* a ma*9e4 ,exp]im5ts ) ! telephone1 a conductor 9 a /rong field or ) a cond5s] or arc1 seem to af=d c]ta9 pro( t s\nds f> above ! usual accept$ limit ( he>+ w\ld be p]ceiv$4 ,a telephone w emit notes ( twelve to ?irte5 ?\s& vibrations p] second2 !n ! inability ( ! core to foll[ su* rapid alt]nations beg9s to tell4 ,if1 h[ev]1 ! magnet & core be replac$ by a cond5s] & ! t]m9als connect$ to ! high-t5sion second>y ( a trans=m]1 high] notes may /ill be he>d4 ,if ! curr5t be s5t ar\nd a f9ely lam9at$ core & a small piece ( ?9 %eet iron be held g5tly aga9/ ! core1 a s\nd may be /ill he>d ) ?irte5 to f\rte5 ?\s& alt]nations p] second1 provid$ ! curr5t is suffici5tly /rong4 ,a small coil1 h[ev]1 tightly pack$ betwe5 ! poles ( a p[]ful magnet1 w emit a s\nd ) ! above numb] ( alt]nations1 & arcs may be audible ) a /ill high] frequ5cy4 ,! limit ( audition is v>i\sly e/imat$4 ,9 ,sir ,william ,?omson's writ+s x is /at$ some:]e t t5 ?\s& p] second1 or ne>ly s1 is ! limit4 ,o!r1 b less reliable1 s\rces give x z high z tw5ty-f\r ?\s& p] second4 ,! above exp]im5ts h conv9c$ ! writ] t notes ( an incomp>ably high] numb] ( vibrations p] second w\ld be p]ceiv$ provid$ !y c\ld be produc$ ) suffici5t p[]4 ,!re is no reason :y x %\ld n be s4 ,! cond5sations & r>efactions ( ! air w\ld necess>ily set ! diaphragm 9 a correspond+ vibration & "s s5sation w\ld be produc$1 :atev]--)9 c]ta9 limits--! velocity ( transmission to _! n]ve c5tres1 ?\gh x is probable t = want ( ex]cise ! e> w\ld n be able to di/+ui% any su* high note4 ,) ! eye x is diff]5t2 if ! s5se ( vision is bas$ ^u "s resonance effect1 z _m believe1 no am\nt ( increase 9 ! int5sity ( ! e!real vibration c\ld ext5d our range ( vision on ei!r side ( ! visible spectrum4 ,! limit ( audition ( an arc dep5ds on its size4 ,! great] ! surface by a giv5 heat+ effect 9 ! arc1 ! high] ! limit ( audition4 ,! highe/ notes are emitt$ by ! high-t5sion dis*>ges ( an induction coil 9 :i* ! arc is1 s to speak1 all surface4 ,if ,r be ! resi/ance ( an arc1 & ,c ! curr5t1 & ! l9e> dim5sions be n times increas$1 !n ! resi/ance is ,r_/n1 & ) ! same curr5t d5sity ! curr5t w\ld be n#b;,c2 h5ce ! heat+ effect is n#c times great]1 :ile ! surface is only n#b times z great4 ,= ?is reason v l>ge arcs w\ld n emit any rhy?mical s\nd ev5 ) a v l[ frequ5cy4 ,x mu/ be obs]v$1 h[ev]1 t ! s\nd emitt$ dep5ds to "s ext5t also on ! composition ( ! c>bon4 ,if ! c>bon conta9 highly refractory mat]ial1 ?is1 :5 heat$1 t5ds to ma9ta9 ! temp]ature ( ! arc uni=m & ! s\nd is less5$2 = ?is reason x w\ld seem t an alt]nat+ arc requires su* c>bons4 ,) curr5ts ( su* high frequ5cies x is possible to obta9 noiseless arcs1 b ! regulation ( ! lamp is r5d]$ extremely difficult on acc\nt ( ! excessively small attractions or repulsions betwe5 conductors convey+ ^! curr5ts4 ,an int]e/+ feature ( ! arc produc$ by ^! rapidly alt]nat+ curr5ts is its p]si/5cy4 ,!re are two causes = x1 "o ( :i* is always pres5t1 ! o!r sometimes only4 ,"o is due to ! "* ( ! curr5t & ! o!r to a prop]ty ( ! ma*9e4 ,! fir/ cause is ! m important "o1 & is due directly to ! rapidity ( ! alt]nations4 ,:5 an arc is =m$ by a p]iodically undulat+ curr5t1 !re is a correspond+ undulation 9 ! temp]ature ( ! gase\s column1 &1 !re=e1 a correspond+ undulation 9 ! resi/ance ( ! arc4 ,b ! resi/ance ( ! arc v>ies enorm\sly ) ! temp]ature ( ! gase\s column1 be+ practically inf9ite :5 ! gas betwe5 ! electrodes is cold4 ,! p]si/5ce ( ! arc1 !re=e1 dep5ds on ! inability ( ! column to cool4 ,x is = ?is reason impossible to ma9ta9 an arc ) ! curr5t alt]nat+ only a few times a second4 ,on ! o!r h&1 ) a practically cont9u\s curr5t1 ! arc is easily ma9ta9$1 ! column be+ con/antly kept at a high temp]ature & l[ resi/ance4 ,! high] ! frequ5cy ! small] ! "t int]val dur+ :i* ! arc may cool & increase consid]ably 9 resi/ance4 ,) a frequ5cy ( #aj1jjj p] second or m 9 an arc ( equal size excessively small v>iations ( temp]ature are sup]impos$ ^u a /eady temp]ature1 l ripples on ! surface ( a deep sea4 ,! heat+ effect is practically cont9u\s & ! arc behaves l "o produc$ by a cont9u\s curr5t1 ) ! exception1 h[ev]1 t x may n be q z easily />t$1 & t ! electrodes are equally consum$2 ?\gh ! writ] has obs]v$ "s irregul>ities 9 ?is respect4 ,! second cause allud$ to1 :i* possibly may n be pres5t1 is due to ! t5d5cy ( a ma*9e ( su* high frequ5cy to ma9ta9 a practically con/ant curr5t4 ,:5 ! arc is l5g!n$1 ! electromotive =ce rises 9 proportion & ! arc appe>s to be m p]si/5t4 ,su* a ma*9e is em95tly adapt$ to ma9ta9 a con/ant curr5t1 b x is v unfit = a con/ant pot5tial4 ,z a matt] ( fact1 9 c]ta9 types ( su* ma*9es a ne>ly con/ant curr5t is an almo/ unavoidable result4 ,z ! numb] ( poles or pol> projections is greatly increas$1 ! cle>ance becomes ( great importance4 ,"o has really to d ) a great numb] ( v small ma*9es4 ,!n !re is ! imp$ance 9 ! armature1 enorm\sly augm5t$ by ! high frequ5cy4 ,!n1 aga91 ! magnetic leakage is facilitat$4 ,if !re are ?ree or f\r hundr$ alt]nate poles1 ! leakage is s great t x is virtually ! same z connect+1 9 a two-pole ma*9e1 ! poles by a piece ( iron4 ,?is disadvantage1 x is true1 may be obviat$ m or less by us+ a field ?r\gh\t ( ! same pol>ity1 b !n "o enc\nt]s difficulties ( a diff]5t nature4 ,all ^! ?+s t5d to ma9ta9 a con/ant curr5t 9 ! armature circuit4 ,9 ?is connection x is int]e/+ to notice t ev5 to-day eng9e]s are a/oni%$ at ! p]=mance ( a con/ant curr5t ma*9e1 j z1 "s ye>s ago1 !y us$ to consid] x an extraord9>y p]=mance if a ma*9e 0 capable ( ma9ta9+ a con/ant pot5tial diff]5ce betwe5 ! t]m9als4 ,yet "o result is j z easily secur$ z ! o!r4 ,x mu/ only be rememb]$ t 9 an inductive app>atus ( any k9d1 if con/ant pot5tial is requir$1 ! inductive relation betwe5 ! prim>y or excit+ & second>y or armature circuit mu/ be ! close/ possible2 :]eas1 9 an app>atus = con/ant curr5t j ! opposite is requir$4 ,fur!rmore1 ! opposition to ! curr5t's fl[ 9 ! induc$ circuit mu/ be z small z possible 9 ! =m] & z great z possible 9 ! latt] case4 ,b opposition to a curr5t's fl[ may be caus$ 9 m ?an "o way4 ,x may be caus$ by ohmic resi/ance or self-induction4 ,"o may make ! induc$ circuit ( a dynamo ma*9e or trans=m] ( su* high resi/ance t :5 op]at+ devices ( consid]ably small] resi/ance )9 v wide limits a ne>ly con/ant curr5t is ma9ta9$4 ,b su* high resi/ance involves a great loss 9 p[]1 h5ce x is n practicable4 ,n s self-induction4 ,self-induction does n necess>ily mean loss ( p[]4 ,! moral is1 use self-induction in/ead ( resi/ance4 ,!re is1 h[ev]1 a circum/ance :i* favors ! adoption ( ?is plan1 & ?is is1 t a v high self-induction may be obta9$ *eaply by surr\nd+ a comp>atively small l5g? ( wire m or less completely ) iron1 &1 fur!rmore1 ! effect may be exalt$ at w by caus+ a rapid undulation ( ! curr5t4 ,to sum up1 ! requirem5ts = con/ant curr5t are3 ,weak magnetic connection betwe5 ! induc$ & induc+ circuits1 greate/ possible self-induction ) ! lea/ resi/ance1 greate/ practicable rate ( *ange ( ! curr5t4 ,con/ant pot5tial1 on ! o!r h&1 requires3 ,close/ magnetic connection betwe5 ! circuits1 /eady induc$ curr5t1 &1 if possible1 no reaction4 ,if ! latt] conditions c\ld be fully satisfi$ 9 a con/ant pot5tial ma*9e1 its output w\ld surpass _m times t ( a ma*9e prim>ily design$ to give con/ant curr5t4 ,un=tunately1 ! type ( ma*9e 9 :i* ^! conditions may be satisfi$ is ( little practical value1 ow+ to ! small electromotive =ce obta9able & ! difficulties 9 tak+ (f ! curr5t4 ,) _! ke5 inv5tor's in/9ct1 ! n[ successful arc-light m5 h e>ly recogniz$ ! desid]ata ( a con/ant curr5t ma*9e4 ,_! arc light ma*9es h weak fields1 l>ge armatures1 ) a great l5g? ( copp] wire & few commutator segm5ts to produce great v>iations 9 ! curr5t's /r5g? & to br+ self-induction into play4 ,su* ma*9es may ma9ta9 )9 consid]able limits ( v>iation 9 ! resi/ance ( ! circuit a practically con/ant curr5t4 ,_! output is ( c\rse correspond+ly dim9i%$1 &1 p]haps ) ! object 9 view n to cut d[n ! output too mu*1 a simple device comp5sat+ exceptional v>iations is employ$4 ,! undulation ( ! curr5t is almo/ ess5tial to ! comm]cial success ( an arc-light sy/em4 ,x introduces 9 ! circuit a /eady+ elem5t tak+ ! place ( a l>ge ohmic resi/ance1 )\t involv+ a great loss 9 p[]1 &1 :at is m important1 x all[s ! use ( simple clut* lamps1 :i* ) a curr5t ( a c]ta9 numb] ( impulses p] second1 be/ suitable = ea* p>ticul> lamp1 w1 if prop]ly att5d$ to1 regulate ev5 bett] ?an ! f9e/ clock-"w lamps4 ,?is discov]y has be5 made by ! writ]--sev]al ye>s too late4 ,x has be5 ass]t$ by compet5t ,engli% electricians t 9 a con/ant-curr5t ma*9e or trans=m] ! regulation is effect$ by v>y+ ! phase ( ! second>y curr5t4 ,t ?is view is errone\s may be easily prov$ by us+1 in/ead ( lamps1 devices ea* possess+ self-induction & capacity or self-induction & resi/ance--t is1 ret>d+ & accel]at+ compon5ts--9 su* proportions z to n affect mat]ially ! phase ( ! second>y curr5t4 ,any numb] ( su* devices may be ins]t$ or cut out1 /ill x w be f\nd t ! regulation occurs1 a con/ant curr5t be+ ma9ta9$1 :ile ! electromotive =ce is v>i$ ) ! numb] ( ! devices4 ,! *ange ( phase ( ! second>y curr5t is simply a result foll[+ f ! *anges 9 resi/ance1 &1 ?\gh second>y reaction is always ( m or less importance1 yet ! real cause ( ! regulation lies 9 ! exi/5ce ( ! conditions above enum]at$4 ,x %\ld be /at$1 h[ev]1 t 9 ! case ( a ma*9e ! above rem>ks are to be re/rict$ to ! cases 9 :i* ! ma*9e is indep5d5tly excit$4 ,if ! excitation be effect$ by commutat+ ! armature curr5t1 !n ! fix$ position ( ! bru%es makes any %ift+ ( ! neutral l9e ( ! utmo/ importance1 & x may n be ?\ght immode/ ( ! writ] to m5tion t1 z f> z records g1 he seems to h be5 ! fir/ :o has successfully regulat$ ma*9es by provid+ a bridge connection betwe5 a po9t ( ! ext]nal circuit & ! commutator by means ( a ?ird bru%4 ,! armature & field be+ prop]ly proportion$ & ! bru%es plac$ 9 _! det]m9$ positions1 a con/ant curr5t or con/ant pot5tial result$ f ! %ift+ ( ! diamet] ( commutation by ! v>y+ loads4 ,9 connection ) ma*9es ( su* high frequ5cies1 ! cond5s] af=ds an especially int]e/+ /udy4 ,x is easy to raise ! electromotive =ce ( su* a ma*9e to f\r or five times ! value by simply connect+ ! cond5s] to ! circuit1 & ! writ] has cont9ually us$ ! cond5s] = ! ! purposes ( regulation1 z sugge/$ by ,blakesley 9 8 book on alt]nate curr5ts1 9 :i* he has treat$ ! mo/ frequ5tly occurr+ cond5s] problems ) exquisite simplicity & cle>ness4 ,! high frequ5cy all[s ! use ( small capacities & r5d]s inve/igation easy4 ,b1 al?\gh 9 mo/ ( ! exp]im5ts ! result may be =etold1 "s ph5om5a obs]v$ seem at fir/ curi\s4 ,"o exp]im5t p]=m$ ?ree or f\r mon?s ago ) su* a ma*9e & a cond5s] may s]ve z an illu/ration4 ,a ma*9e 0 us$ giv+ ab\t #bj1jjj alt]nations p] second4 ,two b>e wires ab\t tw5ty feet long & two millimetres 9 diamet]1 9 close proximity to ea* o!r1 7 connect$ to ! t]m9als ( ! ma*9e at ! "o end1 & to a cond5s] at ! o!r4 ,a small trans=m] )\t an iron core1 ( c\rse1 0 us$ to br+ ! read+ )9 range ( a ,c>dew voltmet] by connect+ ! voltmet] to ! second>y4 ,on ! t]m9als ( ! cond5s] ! electromotive =ce 0 ab\t #abj volts1 & f !re in* by in* x gradually fell until at ! t]m9als ( ! ma*9e x 0 ab\t #fe volts4 ,x 0 virtually z ?\gh ! cond5s] 7 a g5]ator1 & ! l9e & armature circuit simply a resi/ance connect$ to x4 ,! writ] look$ = a case ( resonance1 b he 0 unable to augm5t ! effect by v>y+ ! capacity v c>efully & gradually or by *ang+ ! spe$ ( ! ma*9e4 ,a case ( pure resonance he 0 unable to obta94 ,:5 a cond5s] 0 connect$ to ! t]m9als ( ! ma*9e--! self-induction ( ! armature be+ fir/ det]m9$ 9 ! maximum & m9imum position & ! mean value tak5--! capacity :i* gave ! highe/ electromotive =ce correspond$ mo/ ne>ly to t :i* j c\nt]act$ ! self-induction ) ! exi/+ frequ5cy4 ,if ! capacity 0 increas$ or dim9i%$1 ! electromotive =ce fell z expect$4 ,) frequ5cies z high z ! above m5tion$1 ! cond5s] effects are ( enorm\s importance4 ,! cond5s] becomes a highly effici5t app>atus capable ( transf]r+ consid]able en]gy4 99 99 99 99 99 ,9 an app5dix to ?is book w be f\nd a description ( ! ,tesla oscillator1 :i* its inv5tor believes w among o!r great advantages give him ! necess>y high frequ5cy conditions1 :ile reliev+ him ( ! inconv5i5ces t atta* to g5]ators ( ! type describ$ at ! beg9n+ ( ?is *apt]4 ,,*apt] ,,xxx4 ,,alt]nate ,,curr5t ,,electro/atic ,,induction ,,app>atus4#f #f ,article by ,mr4 ,tesla 9 ,! ,electrical ,eng9e]1 ,n4 ,y41 ,may #f1 #ahia4 ,ab\t a ye> & a half ago :ile engag$ 9 ! /udy ( alt]nate curr5ts ( %ort p]iod1 x occurr$ to me t su* curr5ts c\ld be obta9$ by rotat+ *>g$ surfaces 9 close proximity to conductors4 ,accord+ly ,i devis$ v>i\s =ms ( exp]im5tal app>atus ( :i* two are illu/rat$ 9 ! accompany+ engrav+s4 ,illu/ration3 ,,fig4 #bjh4 ,9 ! app>atus %[n 9 ,fig4 #bjh1 ,a is a r+ ( dry %ellack$ h>d wood provid$ on its inside ) two sets ( t9-foil coat+s1 a & b1 all ! a coat+s & all ! b coat+s be+ connect$ toge!r1 respectively1 b indep5d5t f ea* o!r4 ,^! two sets ( coat+s are connect$ to two t]m9als1 ,t4 ,= ! sake ( cle>ness only a few coat+s are %[n4 ,inside ( ! r+ ,a1 & 9 close proximity to x !re is arrang$ to rotate a cyl9d] ,b1 likewise ( dry1 %ellack$ h>d wood1 & provid$ ) two simil> sets ( coat+s1 a#a & b#a1 all ! coat+s a#a be+ connect$ to "o r+ & all ! o!rs1 b#a1 to ano!r m>k$ & -4 ,^! two sets1 a#a & b#a are *>g$ to a high pot5tial by a ,holtz or ,wim%ur/ ma*9e1 & may be connect$ to a j> ( "s capacity4 ,! inside ( r+ ,a is coat$ ) mica 9 ord] to increase ! induction & also to all[ high] pot5tials to be us$4 ,illu/ration3 ,,fig4 #bji4 ,:5 ! cyl9d] ,b ) ! *>g$ coat+s is rotat$1 a circuit connect$ to ! t]m9als ,t is trav]s$ by alt]nat+ curr5ts4 ,ano!r =m ( app>atus is illu/rat$ 9 ,fig4 #bji4 ,9 ?is app>atus ! two sets ( t9-foil coat+s are glu$ on a plate ( ebonite1 & a simil> plate :i* is rotat$1 & ! coat+s ( :i* are *>g$ z 9 ,fig4 #bjh1 is provid$4 ,! output ( su* an app>atus is v small1 b "s ( ! effects peculi> to alt]nat+ curr5ts ( %ort p]iods may be obs]v$4 ,! effects1 h[ev]1 _c be comp>$ ) ^? obta9able ) an induction coil :i* is op]at$ by an alt]nate curr5t ma*9e ( high frequ5cy1 "s ( :i* 7 describ$ by me a %ort :ile ago4 ,,*apt] ,,xxxi4 ,,massage ,,) ,,curr5ts ,,( ,,high ,,frequ5cy4#g #g ,article by ,mr4 ,tesla 9 ,! ,electrical ,eng9e] ( ,dec4 #bc;d1 #ahia4 ,i tru/ t ! pres5t brief communication w n be int]pret$ z an ef=t on my "p to put myself on record z a pat5t m$ic9e man1 = a s]i\s work] _c despise any?+ m ?an ! misuse & abuse ( electricity :i* we h frequ5t occasion to witness4 ,my rem>ks are elicit$ by ! lively int]e/ :i* prom95t m$ical practition]s ev9ce at e real advance 9 electrical inve/igation4 ,! progress 9 rec5t ye>s has be5 s great t e electrician & electrical eng9e] is confid5t t electricity w become ! means ( accompli%+ _m ?+s t h be5 h]et(ore1 ) our exi/+ k1 deem$ impossible4 ,no wond] !n t progressive physicians also %\ld expect to f9d 9 x a p[]ful tool & help 9 new curative processes4 ,s9ce ,i _h ! honor to br+ be=e ! ,am]ican ,in/itute ( ,electrical ,eng9e]s "s results 9 utiliz+ alt]nat+ curr5ts ( high t5sion1 ,i h receiv$ _m lett]s f not$ physicians inquir+ z to ! physical effects ( su* curr5ts ( high frequ5cy4 ,x may be rememb]$ t ,i !n demon/rat$ t a body p]fectly well insulat$ 9 air c be heat$ by simply connect+ x ) a s\rce ( rapidly alt]nat+ high pot5tial4 ,! heat+ 9 ?is case is due 9 all probability to ! bomb>dm5t ( ! body by air1 or possibly by "s o!r m$ium1 :i* is molecul> or atomic 9 con/ruction1 & ! pres5ce ( :i* has s f> escap$ our analysis--= accord+ to my ideas1 ! true e!r radiation ) su* frequ5cies z ev5 a few millions p] second mu/ be v small4 ,?is body may be a good conductor or x may be a v poor conductor ( electricity ) little *ange 9 ! result4 ,! human body is1 9 su* a case1 a f9e conductor1 & if a p]son insulat$ 9 a room1 or no matt] :]e1 is br\ght into contact ) su* a s\rce ( rapidly alt]nat+ high pot5tial1 ! sk9 is heat$ by bomb>dm5t4 ,x is a m]e "q ( ! dim5sions & "* ( ! app>atus to produce any degree ( heat+ desir$4 ,x has occurr$ to me :e!r1 ) su* app>atus prop]ly prep>$1 x w\ld n be possible = a skill$ physician to f9d 9 x a means = ! effective treatm5t ( v>i\s types ( disease4 ,! heat+ w1 ( c\rse1 be sup]ficial1 t is1 on ! sk91 & w\ld result1 :e!r ! p]son op]at$ on 7 9 b$ or walk+ ar\nd a room1 :e!r dress$ 9 ?ick clo!s or :e!r r$uc$ to nak$ness4 ,9 fact1 to put x broadly1 x is conceivable t a p]son entirely nude at ! ,nor? ,pole might keep himself com=tably w>m 9 ?is mann]4 ,)\t v\*+ = all ! results1 :i* mu/1 ( c\rse1 be det]m9$ by exp]i5ce & obs]vation1 ,i c at lea/ w>rant ! fact t heat+ w\ld occur by ! use ( ?is me?od ( subject+ ! human body to bomb>dm5t by alt]nat+ curr5ts ( high pot5tial & frequ5cy su* ,i h long work$ )4 ,x is only reasonable to expect t "s ( ! novel effects w be :olly diff]5t f ^? obta9able ) ! old famili> !rapeutic me?ods g5]ally us$4 ,:e!r !y w\ld all be b5eficial or n rema9s to be prov$4 ,,*apt] ,,xxxii4 ,,electric ,,dis*>ge ,,9 ,,vacuum ,,tubes4#h #h ,article by ,mr4 ,tesla 9 ,! ,electrical ,eng9e]4 ,n4 ,y41 ,july #a1 #ahia4 ,9 ,! ,electrical ,eng9e] ( ,june #aj ,i h not$ ! description ( "s exp]im5ts ( ,pr(4 ,j4 ,j4 ,?omson1 on ! ,electric ,dis*>ge 9 ,vacuum ,tubes1 & 9 y\r issue ( ,june #bd ,pr(4 ,elihu ,?omson describes an exp]im5t ( ! same k9d4 ,! fundam5tal idea 9 ^! exp]im5ts is to set up an electromotive =ce 9 a vacuum tube---pref]ably devoid ( any electrodes--by means ( electro-magnetic induction1 & to excite ! tube 9 ?is mann]4 ,z ,i view ! subject ,i %\ld1 ?9k t to any exp]im5t] :o _h c>efully /udi$ ! problem confront+ u & :o attempt$ to f9d a solution ( x1 ?is idea mu/ pres5t itself z naturally z1 = in/ance1 ! idea ( replac+ ! t9foil coat+s ( a ,leyd5 j> by r>efi$ gas & excit+ lum9osity 9 ! cond5s] ?us obta9$ by repeat$ly *>g+ & dis*>g+ x4 ,! idea be+ obvi\s1 :atev] m]it !re is 9 ?is l9e ( inve/igation mu/ dep5d ^u ! complet5ess ( ! /udy ( ! subject & ! correctness ( ! obs]vations4 ,! foll[+ l9es are n p5n$ ) any desire on my "p to put myself on record z "o :o has p]=m$ simil> exp]im5ts1 b ) a desire to assi/ o!r exp]im5t]s by po9t+ out c]ta9 peculi>ities ( ! ph5om5a obs]v$1 :i*1 to all appe>ances1 h n be5 not$ by ,pr(4 ,j4 ,j4 ,?omson1 :o1 h[ev]1 seems to h gone ab\t sy/ematically 9 8 inve/igations1 & :o has be5 ! fir/ to make 8 results kn[n4 ,^! peculi>ities not$ by me w\ld seem to be at v>iance ) ! views ( ,pr(4 ,j4 ,j4 ,?omson1 & pres5t ! ph5om5a 9 a diff]5t light4 ,my inve/igations 9 ?is l9e occupi$ me pr9cipally dur+ ! w9t] & spr+ ( ! pa/ ye>4 ,dur+ ?is "t _m diff]5t exp]im5ts 7 p]=m$1 & 9 my ex*anges ( ideas on ?is subject ) ,mr4 ,alfr$ ,s4 ,br[n1 ( ! ,we/]n ,union ,telegraph ,company1 v>i\s diff]5t dispositions 7 sugge/$ :i* 7 c>ri$ out by me 9 practice4 ,fig4 #baj may s]ve z an example ( "o ( ! _m =ms ( app>atus us$4 ,?is consi/$ ( a l>ge glass tube seal$ at "o end & project+ into an ord9>y inc&esc5t lamp bulb4 ,! prim>y1 usually consi/+ ( a few turns ( ?ick1 well-insulat$ copp] %eet 0 ins]t$ )9 ! tube1 ! inside space ( ! bulb furni%+ ! second>y4 ,?is =m ( app>atus 0 arriv$ at aft] "s exp]im5t+1 & 0 us$ pr9cipally ) ! view ( enabl+ me to place a poli%$ reflect+ surface on ! inside ( ! tube1 & = ?is purpose ! la/ turn ( ! prim>y 0 cov]$ ) a ?9 silv] %eet4 ,9 all =ms ( app>atus us$ !re 0 no special difficulty 9 excit+ a lum9\s circle or cyl9d] 9 proximity to ! prim>y4 ,illu/ration3 ,,fig4 #baj4 ,z to ! numb] ( turns1 ,i _c q und]/& :y ,pr(4 ,j4 ,j4 ,?omson %\ld ?9k t a few turns 7 q suffici5t1 b le/ ,i %\ld impute to him an op9ion he may n h1 ,i w add t ,i h ga9$ ?is impression f ! read+ ( ! publi%$ ab/racts ( 8 lecture4 ,cle>ly1 ! numb] ( turns :i* gives ! be/ result 9 any case1 is dep5d5t on ! dim5sions ( ! app>atus1 &1 7 x n = v>i\s consid]ations1 "o turn w\ld always give ! be/ result4 ,i h f\nd t x is pref]able to use 9 ^! exp]im5ts an alt]nate curr5t ma*9e giv+ a mod]ate numb] ( alt]nations p] second to excite ! induction coil = *>g+ ! ,leyd5 j> :i* dis*>ges ?r\gh ! prim>y--%[n diagrammatically 9 ,fig4 #baa1--;z 9 su* case1 be=e ! disruptive dis*>ge takes place1 ! tube or bulb is slightly excit$ & ! =mation ( ! lum9\s circle is decid$ly facilitat$4 ,b ,i h also us$ a ,wim%ur/ ma*9e 9 "s exp]im5ts4 ,illu/ration3 ,,fig4 #baa4 ,pr(4 ,j4 ,j4 ,?omson's view ( ! ph5om5a "u consid]ation seems to be t !y are :olly due to electro-magnetic action4 ,i 01 at "o "t1 ( ! same op9ion1 b ^u c>efully inve/igat+ ! subject ,i 0 l$ to ! conviction t !y are m ( an electro/atic nature4 ,x mu/ be rememb]$ t 9 ^! exp]im5ts we h to deal ) prim>y curr5ts ( an enorm\s frequ5cy or rate ( *ange & ( high pot5tial1 & t ! second>y conductor consi/s ( a r>efi$ gas1 & t "u su* conditions electro/atic effects mu/ play an important "p4 ,illu/ration3 ,,fig4 #bab4 ,9 support ( my view ,i w describe a few exp]im5ts made by me4 ,to excite lum9osity 9 ! tube x is n absolutely necess>y t ! conductor %\ld be clos$4 ,= in/ance1 if an ord9>y exhau/$ tube 7pref]ably ( l>ge diamet]7 be surr\nd$ by a spiral ( ?ick copp] wire s]v+ z ! prim>y1 a feebly lum9\s spiral may be induc$ 9 ! tube1 r\ghly %[n 9 ,fig4 #bab4 ,9 "o ( ^! exp]im5ts a curi\s ph5om5on 0 obs]v$2 namely1 two int5sely lum9\s circles1 ea* ( !m close to a turn ( ! prim>y spiral1 7 =m$ inside ( ! tube1 & ,i attribut$ ?is ph5om5on to ! exi/5ce ( nodes on ! prim>y4 ,! circles 7 connect$ by a fa9t lum9\s spiral p>allel to ! prim>y & 9 close proximity to x4 ,to produce ?is effect ,i h f\nd x necess>y to /ra9 ! j> to ! utmo/4 ,! turns ( ! spiral t5d to close & =m circles1 b ?is1 ( c\rse1 w\ld be expect$1 & does n necess>ily indicate an electro-magnetic effect2 ,:]eas ! fact t a gl[ c be produc$ along ! prim>y 9 ! =m ( an op5 spiral argues = an electro/atic effect4 ,illu/ration3 ,,fig4 #bac4 ,9 us+ ,dr4 ,lodge's recoil circuit1 ! electro/atic action is likewise app>5t4 ,! arrangem5t is illu/rat$ 9 ,fig4 #bac4 ,9 8 exp]im5t two holl[ exhau/$ tubes ,h ,h 7 slipp$ ov] ! wires ( ! recoil circuit & ^u dis*>g+ ! j> 9 ! usual mann] lum9osity 0 excit$ 9 ! tubes4 ,ano!r exp]im5t p]=m$ is illu/rat$ 9 ,fig4 #bad4 ,9 ?is case an ord9>y lamp-bulb 0 surr\nd$ by "o or two turns ( ?ick copp] wire ,p & ! lum9\s circle ,l excit$ 9 ! bulb by dis*>g+ ! j> ?r\gh ! prim>y4 ,! lamp-bulb 0 provid$ ) a t9foil coat+ on ! side opposite to ! prim>y & ea* "t ! t9foil coat+ 0 connect$ to ! gr\nd or to a l>ge object ! lum9osity ( ! circle 0 consid]ably increas$4 ,?is 0 evid5tly due to electro/atic action4 ,9 o!r exp]im5ts ,i h not$ t :5 ! prim>y t\*es ! glass ! lum9\s circle is easi] produc$ & is m %>ply def9$2 b ,i h n not$ t1 g5]ally speak+1 ! circles induc$ 7 v %>ply def9$1 z ,pr(4 ,j4 ,j4 ,?omson has obs]v$2 on ! contr>y1 9 my exp]im5ts !y 7 broad & (t5 ! :ole ( ! bulb or tube 0 illum9at$2 & 9 "o case ,i h obs]v$ an int5sely purpli% gl[1 to :i* ,pr(4 ,j4 ,j4 ,?omson ref]s4 ,b ! circles 7 always 9 close proximity to ! prim>y & 7 consid]ably easi] produc$ :5 ! latt] 0 v close to ! glass1 mu* m s ?an w\ld be expect$ assum+ ! action to be electromagnetic & consid]+ ! di/ance2 & ^! facts speak = an electro/atic effect4 ,illu/ration3 ,,fig4 #bad4 ,illu/ration3 ,,fig4 #bae4 ,fur!rmore ,i h obs]v$ t !re is a molecul> bomb>dm5t 9 ! plane ( ! lum9\s circle at "r angles to ! glass--suppos+ ! circle to be 9 ! plane ( ! prim>y--?is bomb>dm5t be+ evid5t f ! rapid heat+ ( ! glass ne> ! prim>y4 ,7 ! bomb>dm5t n at "r angles to ! glass ! heat+ c\ld n be s rapid4 ,if !re is a circumf]5tial movem5t ( ! molecules con/itut+ ! lum9\s circle1 ,i h ?\ght t x might be r5d]$ manife/ by plac+ )9 ! tube or bulb1 radially to ! circle1 a ?9 plate ( mica coat$ ) "s phosphoresc5t mat]ial & ano!r su* plate tang5tially to ! circle4 ,if ! molecules w\ld move circumf]5tially1 ! =m] plate w\ld be r5d]$ m int5sely phosphoresc5t4 ,= want ( "t ,i h1 h[ev]1 n be5 able to p]=m ! exp]im5t4 ,ano!r obs]vation made by me 0 t :5 ! specific inductive capacity ( ! m$ium betwe5 ! prim>y & second>y is increas$1 ! inductive effect is augm5t$4 ,?is is r\ghly illu/rat$ 9 ,fig4 #bae4 ,9 ?is case lum9osity 0 excit$ 9 an exhau/$ tube or bulb ,b & a glass tube ,t slipp$ betwe5 ! prim>y & ! bulb1 :5 ! effect po9t$ out 0 not$4 ,7 ! action :olly electromagnetic no *ange c\ld possibly h be5 obs]v$4 ,i h likewise not$ t :5 a bulb is surr\nd$ by a wire clos$ ^u itself & 9 ! plane ( ! prim>y1 ! =mation ( ! lum9\s circle )9 ! bulb is n prev5t$4 ,b if in/ead ( ! wire a broad /rip ( t9foil is glu$ ^u ! bulb1 ! =mation ( ! lum9\s b& 0 prev5t$1 because !n ! action 0 di/ribut$ ov] a great] surface4 ,! effect ( ! clos$ t9foil 0 no d\bt ( an electro/atic nature1 = x pres5t$ a mu* great] resi/ance ?an ! clos$ wire & produc$ !re=e a mu* small] electromagnetic effect4 ,"s ( ! exp]im5ts ( ,pr(4 ,j4 ,j4 ,?omson also w\ld seem to %[ "s electro/atic action4 ,= in/ance1 9 ! exp]im5t ) ! bulb enclos$ 9 a bell j>1 ,i %\ld ?9k t :5 ! latt] is exhau/$ s f> t ! gas enclos$ rea*es ! maximum conductivity1 ! =mation ( ! circle 9 ! bulb & j> is prev5t$ because ( ! space surr\nd+ ! prim>y be+ highly conduct+2 :5 ! j> is fur!r exhau/$1 ! conductivity ( ! space ar\nd ! prim>y dim9i%es & ! circles appe> necess>ily fir/ 9 ! bell j>1 z ! r>efi$ gas is ne>] to ! prim>y4 ,b 7 ! inductive effect v p[]ful1 !y w\ld probably appe> 9 ! bulb also4 ,if1 h[ev]1 ! bell j> 7 exhau/$ to ! highe/ degree !y w\ld v likely %[ !mselves 9 ! bulb only1 t is1 suppos+ ! vacu\s space to be non-conduct+4 ,on ! assumption t 9 ^! ph5om5a electro/atic actions are conc]n$ we f9d x easily explicable :y ! introduction ( m]cury or ! heat+ ( ! bulb prev5ts ! =mation ( ! lum9\s b& or %ort5s ! aft]-gl[2 & also :y 9 "s cases a plat9um wire may prev5t ! excitation ( ! tube4 ,nev]!less "s ( ! exp]im5ts ( ,pr(4 ,j4 ,j4 ,?omson w\ld seem to indicate an electromagnetic effect4 ,i may add t 9 "o ( my exp]im5ts 9 :i* a vacuum 0 produc$ by ! ,torricellian me?od1 ,i 0 unable to produce ! lum9\s b&1 b ?is may h be5 due to ! weak excit+ curr5t employ$4 ,my pr9cipal argum5t is ! foll[+3 ,i h exp]im5tally prov$ t if ! same dis*>ge :i* is b>ely suffici5t to excite a lum9\s b& 9 ! bulb :5 pass$ ?r\gh ! prim>y circuit be s direct$ z to exalt ! electro/atic inductive effect--namely1 by conv]t+ upw>ds--an exhau/$ tube1 devoid ( electrodes1 may be excit$ at a di/ance ( sev]al feet4 ,,"s ,,exp]im5ts ,,on ,,! ,,electric ,,dis*>ge ,,9 ,,vacuum ,,tubes4#i ,,by ,,pr(4 ,j4 ,j4 ,,?omson1 ,m4,a41 ,f4,r4,s4 #i ,ab/ract ( a pap] read be=e ,physical ,society ( ,london4 ,illu/ration3 ,,fig4 #baf4 ,illu/ration3 ,,fig4 #bag4 ,illu/ration3 ,,fig4 #bah4 ,illu/ration3 ,,fig4 #bai4 ,! ph5om5a ( vacuum dis*>ges 71 ,pr(4 ,?omson said1 greatly simplifi$ :5 _! pa? 0 :olly gase\s1 ! complication ( ! d>k space surr\nd+ ! negative electrode1 & ! /ratifications s commonly obs]v$ 9 ord9>y vacuum tubes1 be+ abs5t4 ,to produce dis*>ges 9 tubes devoid ( electrodes 01 h[ev]1 n easy to accompli%1 = ! only available means ( produc+ an electromotive =ce 9 ! dis*>ge circuit 0 by electro-magnetic induction4 ,ord9>y me?ods ( produc+ v>iable induction 7 valueless1 & rec\rse 0 _h to ! oscillatory dis*>ge ( a ,leyd5 j>1 :i* comb9es ! two ess5tials ( a curr5t ^: maximum value is enorm\s1 & ^: rapidity ( alt]nation is imm5sely great4 ,! dis*>ge circuits1 :i* may take ! %ape ( bulbs1 or ( tubes b5t 9 ! =m ( coils1 7 plac$ 9 close proximity to glass tubes fill$ ) m]cury1 :i* =m$ ! pa? ( ! oscillatory dis*>ge4 ,! p>ts ?us correspond$ to ! w9d+s ( an induction coil1 ! vacuum tubes be+ ! second>y1 & ! tubes fill$ ) m]cury ! prim>y4 ,9 su* an app>atus ! ,leyd5 j> ne$ n be l>ge1 & nei!r prim>y nor second>y ne$ h _m turns1 = ?is w\ld increase ! self-induction ( ! =m]1 & l5g!n ! dis*>ge pa? 9 ! latt]4 ,increas+ ! self-induction ( ! prim>y r$uces ! ,e4 ,m4 ,f4 induc$ 9 ! second>y1 :il/ l5g!n+ ! second>y does n increase ! ,e4 ,m4 ,f4 p] unit l5g?4 ,! two or ?ree turns1 z %[n 9 ,fig4 #baf1 9 ea*1 7 f\nd to be q suffici5t1 &1 on dis*>g+ ! ,leyd5 j> betwe5 two highly poli%$ knobs 9 ! prim>y circuit1 a pla9 uni=m b& ( light 0 se5 to pass r\nd ! second>y4 ,an exhau/$ bulb1 ,fig4 #bag1 conta9+ traces ( oxyg5 0 plac$ )9 a prim>y spiral ( ?ree turns1 &1 on pass+ ! j> dis*>ge1 a circle ( light 0 se5 )9 ! bulb 9 close proximity to ! prim>y circuit1 accompani$ by a purpli% gl[1 :i* la/$ = a second or m4 ,on heat+ ! bulb1 ! duration ( ! gl[ 0 greatly dim9i%$1 & x c\ld be in/antly ext+ui%$ by ! pres5ce ( an electro-magnet4 ,ano!r exhau/$ bulb1 ,fig4 #bah1 surr\nd$ by a prim>y spiral1 0 conta9$ 9 a bell-j>1 & :5 ! pressure ( air 9 ! j> 0 ab\t t ( ! atmosph]e1 ! second>y dis*>ge occurr$ 9 ! bulb1 z is ord9>ily ! case4 ,on exhau/+ ! j>1 h[ev]1 ! lum9\s dis*>ge grew fa9t]1 & a po9t 0 rea*$ at :i* no second>y dis*>ge 0 visible4 ,fur!r exhau/ion ( ! j> caus$ ! second>y dis*>ge to appe> outside ( ! bulb4 ,! fact ( obta9+ no lum9\s dis*>ge1 ei!r 9 ! bulb or j>1 ! au?or c\ld only expla9 on two suppositions1 viz43 t "u ! conditions !n exi/+ ! specific inductive capacity ( ! gas 0 v great1 or t a dis*>ge c\ld pass )\t be+ lum9\s4 ,! au?or _h also obs]v$ t ! conductivity ( a vacuum tube )\t electrodes increas$ z ! pressure dim9i%$1 until a c]ta9 po9t 0 rea*$1 & aft]w>ds dim9i%$ aga91 ?us %[+ t ! high resi/ance ( a ne>ly p]fect vacuum is 9 no way due to ! pres5ce ( ! electrodes4 ,"o peculi>ity ( ! dis*>ges 0 _! local nature1 ! r+s ( light be+ mu* m %>ply def9$ ?an 0 to be expect$4 ,!y 7 also f\nd to be mo/ easily produc$ :5 ! *a9 ( molecules 9 ! dis*>ge 7 all ( ! same k9d4 ,= example1 a dis*>ge c\ld be easily s5t ?r\gh a tube _m feet long1 b ! introduction ( a small pellet ( m]cury 9 ! tube /opp$ ! dis*>ge1 al?\gh ! conductivity ( ! m]cury 0 mu* great] ?an t ( ! vacuum4 ,9 "s cases he _h notic$ t a v f9e wire plac$ )9 a tube1 on ! side remote f ! prim>y circuit1 w\ld prev5t a lum9\s dis*>ge 9 t tube4 ,fig4 #bai %[s an exhau/$ second>y coil ( "o loop conta9+ bulbs2 ! dis*>ge pass$ along ! inn] side ( ! bulbs1 ! prim>y coils be+ plac$ )9 ! second>y4 #i;,9 ,! ,electrical ,eng9e] ( ,augu/ #ab1 ,i f9d "s rem>ks ( ,pr(4 ,j4 ,j4 ,?omson1 :i* appe>$ orig9ally 9 ! ,london ,electrician & :i* h a be>+ ^u "s exp]im5ts describ$ by me 9 y\r issue ( ,july #a4 #i ,article by ,mr4 ,tesla 9 ,! ,electrical ,eng9e]1 ,n4 ,y41 ,augu/ #bf1 #ahia4 ,i did n1 z ,pr(4 ,j4 ,j4 ,?omson seems to believe1 misund]/& 8 position 9 reg>d to ! cause ( ! ph5om5a consid]$1 b ,i ?\ght t 9 8 exp]im5ts1 z well z 9 my own1 electro/atic effects 7 ( great importance4 ,x did n appe>1 f ! meagre description ( 8 exp]im5ts1 t all possible precautions _h be5 tak5 to exclude ^! effects4 ,i did n d\bt t lum9osity c\ld be excit$ 9 a clos$ tube :5 electro/atic action is completely exclud$4 ,9 fact1 at ! outset1 ,i myself look$ = a purely electrodynamic effect & believ$ t ,i _h obta9$ x4 ,b _m exp]im5ts p]=m$ at t "t prov$ to me t ! electro/atic effects 7 g5]ally ( f> great] importance1 & admitt$ ( a m satisfactory explanation ( mo/ ( ! ph5om5a obs]v$4 ,9 us+ ! t]m electro/atic ,i _h ref]5ce r to ! nature ( ! action ?an to a /ation>y condition1 :i* is ! usual acceptance ( ! t]m4 ,to express myself m cle>ly1 ,i w suppose t ne> a clos$ exhau/$ tube be plac$ a small sph]e *>g$ to a v high pot5tial4 ,! sph]e w\ld act inductively ^u ! tube1 & by di/ribut+ electricity ov] ! same w\ld und\bt$ly produce lum9osity 7if ! pot5tial be suffici5tly high71 until a p]man5t condition w\ld be rea*$4 ,assum+ ! tube to be p]fectly well insulat$1 !re w\ld be only "o in/antane\s fla% dur+ ! act ( di/ribution4 ,?is w\ld be due to ! electro/atic action simply4 ,b n[1 suppose ! *>g$ sph]e to be mov$ at %ort int]vals ) great spe$ along ! exhau/$ tube4 ,! tube w\ld n[ be p]man5tly excit$1 z ! mov+ sph]e w\ld cause a con/ant r$i/ribution ( electricity & collisions ( ! molecules ( ! r>efi$ gas4 ,we w\ld /ill h to deal ) an electro/atic effect1 & 9 addition an electrodynamic effect w\ld be obs]v$4 ,b if x 7 f\nd t1 = in/ance1 ! effect produc$ dep5d$ m on ! specific inductive capacity ?an on ! magnetic p]meability ( ! m$ium--:i* w\ld c]ta9ly be ! case = spe$s incomp>ably l[] ?an t ( light--!n ,i believe ,i w\ld be ju/ifi$ 9 say+ t ! effect produc$ 0 m ( an electro/atic nature4 ,i d n mean to say1 h[ev]1 t any simil> condition prevails 9 ! case ( ! dis*>ge ( a ,leyd5 j> ?r\gh ! prim>y1 b ,i ?9k t su* an action w\ld be desirable4 ,x is 9 ! _s ( ! above example t ,i us$ ! t]ms m ( an electro/atic nature1 & h inve/igat$ ! influ5ce ( bodies ( high specific inductive capacity1 & obs]v$1 = in/ance1 ! importance ( ! quality ( glass ( :i* ! tube is made4 ,i also endeavor$ to asc]ta9 ! influ5ce ( a m$ium ( high p]meability by us+ oxyg54 ,x appe>$ f r\gh e/imation t an oxyg5 tube :5 excit$ "u simil> conditions--t is1 z f> z c\ld be det]m9$--gives m light2 b ?is1 ( c\rse1 may be due to _m causes4 ,)\t d\bt+ 9 ! lea/ t1 ) ! c>e & precautions tak5 by ,pr(4 ,j4 ,j4 ,?omson1 ! lum9osity excit$ 0 due solely to electrodynamic action1 ,i w\ld say t 9 _m exp]im5ts ,i h obs]v$ curi\s in/ances ( ! ineffectiv5ess ( ! scre5+1 & ,i h also f\nd t ! electrification ?r\gh ! air is (t5 ( v great importance1 & may1 9 "s cases1 det]m9e ! excitation ( ! tube4 ,9 8 orig9al communication to ! ,electrician1 ,pr(4 ,j4 ,j4 ,?omson ref]s to ! fact t ! lum9osity 9 a tube ne> a wire ?r\gh :i* a ,leyd5 j> 0 dis*>g$ 0 not$ by ,hittorf4 ,i ?9k t ! feeble lum9\s effect ref]r$ to has be5 not$ by _m exp]im5t]s1 b 9 my exp]im5ts ! effects 7 mu* m p[]ful ?an ^? usually not$4 ,! foll[+ is ! communication#aj ref]r$ to3-- #aj ,note by ,pr(4 ,j4 ,j4 ,?omson 9 ! ,london ,electrician1 ,july #bd1 #ahia4 ,mr4 ,tesla seems to ascribe ! effects he obs]v$ to electro/atic action1 & ,i h no d\bt1 f ! description he gives ( 8 me?od ( conduct+ 8 exp]im5ts1 t 9 !m electro/atic action plays a v important "p4 ,he seems1 h[ev]1 to h misund]/ood my position ) respect to ! cause ( ^! dis*>ges1 :i* is n1 z he implies1 t lum9osity 9 tubes )\t electrodes _c be produc$ by electro/atic action1 b t x c also be produc$ :5 ?is action is exclud$4 ,z a matt] ( fact1 x is v mu* easi] to get ! lum9osity :5 ^! electro/atic effects are op]ative ?an :5 !y are n4 ,z an illu/ration ( ?is ,i may m5tion t ! fir/ exp]im5t ,i tri$ ) ! dis*>ge ( a ,leyd5 j> produc$ lum9osity 9 ! tube1 b x 0 n until aft] six weeks' cont9u\s exp]im5t+ t ,i 0 able to get a dis*>ge 9 ! exhau/$ tube :i* ,i 0 satisfi$ 0 due to :at is ord9>ily call$ electrodynamic action4 ,x is advisable to h a cle> idea ( :at we mean by electro/atic action4 ,if1 previ\s to ! dis*>ge ( ! j>1 ! prim>y coil is rais$ to a high pot5tial1 x w induce ov] ! glass ( ! tube a di/ribution ( electricity4 ,:5 ! pot5tial ( ! prim>y sudd5ly falls1 ?is electrification w r$i/ribute itself1 & may pass ?r\gh ! r>efi$ gas & produce lum9osity 9 do+ s4 ,:il/ ! dis*>ge ( ! j> is go+ on1 x is difficult1 &1 f a !oretical po9t ( view1 undesirable1 to sep>ate ! effect into p>ts1 "o ( :i* is call$ electro/atic1 ! o!r electromagnetic2 :at we c prove is t 9 ?is case ! dis*>ge is n su* z w\ld be produc$ by electromotive =ces d]iv$ f a pot5tial function4 ,9 my exp]im5ts ! prim>y coil 0 connect$ to e>?1 &1 z a fur!r precaution1 ! prim>y 0 sep>at$ f ! dis*>ge tube by a scre5 ( blott+ pap]1 moi/5$ ) dilute sulphuric acid1 & connect$ to e>?4 ,wet blott+ pap] is a suffici5tly good conductor to scre5 (f a /ation>y electro/atic effect1 ?\gh x is n a good en\gh "o to /op waves ( alt]nat+ electromotive int5sity4 ,:5 %[+ ! exp]im5ts to ! ,physical ,society ,i c\ld n1 ( c\rse1 keep ! tubes cov]$ up1 b1 unless my memory deceives me1 ,i /at$ ! precautions :i* _h be5 tak5 aga9/ ! electro/atic effect4 ,to correct misappreh5sion ,i may /ate t ,i did n read a =mal pap] to ! ,society1 my object be+ to exhibit a few ( ! mo/ typical exp]im5ts4 ,! acc\nt ( ! exp]im5ts 9 ! ,electrician 0 f a report]'s note1 & 0 n writt51 or ev5 read1 by me4 ,i h n[ almo/ f9i%$ writ+ out1 & hope v %ortly to publi%1 an acc\nt ( ^! & a l>ge numb] ( alli$ exp]im5ts1 includ+ "s analog\s to ^? m5tion$ by ,mr4 ,tesla on ! effect ( conductors plac$ ne> ! dis*>ge tube1 :i* ,i f9d1 9 "s cases1 to produce a dim9ution1 9 o!rs an increase1 9 ! brightness ( ! dis*>ge1 z well z "s on ! effect ( ! pres5ce ( sub/ances ( l>ge specific inductive capacity4 ,^! seem to me to admit ( a satisfactory explanation1 = :i*1 h[ev]1 ,i mu/ ref] to my pap]4 ,,"p ,,iii4 ,,miscellane\s ,,inv5tions ,,& ,,writ+s4 ,,*apt] ,,xxxiii4 ,,me?od ,,( ,,obta9+ ,,driect ,,f ,,alt]nat+ ,,curr5ts4 ,?is me?od consi/s 9 obta9+ direct f alt]nat+ curr5ts1 or 9 direct+ ! waves ( an alt]nat+ curr5t s z to produce direct or sub/antially direct curr5ts by develop+ or produc+ 9 ! bran*es ( a circuit includ+ a s\rce ( alt]nat+ curr5ts1 ei!r p]man5tly or p]iodically1 & by electric1 electro-magnetic1 or magnetic ag5cies1 manife/ations ( en]gy1 or :at may be t]m$ active resi/ances ( opposite electrical "*1 :]eby ! curr5ts or curr5t waves ( opposite sign w be div]t$ ?r\gh diff]5t circuits1 ^? ( "o sign pass+ ov] "o bran* & ^? ( opposite sign ov] ! o!r4 ,we may consid] h]e9 only ! case ( a circuit divid$ into two pa?s1 inasmu* z any fur!r subdivision involves m]ely an ext5sion ( ! g5]al pr9ciple4 ,select+1 !n1 any circuit ?r\gh :i* is fl[+ an alt]nat+ curr5t1 ,mr4 ,tesla divides su* circuit at any desir$ po9t into two bran*es or pa?s4 ,9 "o ( ^! pa?s he ins]ts "s device to create an electromotive =ce c\nt] to ! waves or impulses ( curr5t ( "o sign & a simil> device 9 ! o!r bran* :i* opposes ! waves ( opposite sign4 ,assume1 = example1 t ^! devices are batt]ies1 prim>y or second>y1 or cont9u\s curr5t dynamo ma*9es4 ,! waves or impulses ( opposite direction compos+ ! ma9 curr5t h a natural t5d5cy to divide betwe5 ! two bran*es2 b by reason ( ! opposite electrical "* or effect ( ! two bran*es1 "o w (f] an easy passage to a curr5t ( a c]ta9 direction1 :ile ! o!r w (f] a relatively high resi/ance to ! passage ( ! same curr5t4 ,! result ( ?is disposition is1 t ! waves ( curr5t ( "o sign w1 p>tly or :olly1 pass ov] "o ( ! pa?s or bran*es1 :ile ^? ( ! opposite sign pass ov] ! o!r4 ,!re may ?us be obta9$ f an alt]nat+ curr5t two or m direct curr5ts )\t ! employm5t ( any commutator su* z x has be5 h]et(ore reg>d$ z necess>y to use4 ,! curr5t 9 ei!r bran* may be us$ 9 ! same way & = ! same purposes z any o!r direct curr5t--t is1 x may be made to *>ge second>y batt]ies1 en]gize electro-magnets1 or = any o!r analog\s purpose4 ,fig4 #bbj repres5ts a plan ( direct+ ! alt]nat+ curr5ts by means ( devices purely electrical 9 "*4 ,figs4 #bba1 #bbb1 #bbc1 #bbd1 #bbe1 & #bbf are diagrams illu/rative ( o!r ways ( c>ry+ out ! inv5tion4 ,illu/ration3 ,,fig4 #bbj4 ,9 ,fig4 #bbj1 ,a designates a g5]ator ( alt]nat+ curr5ts1 & ,b ,b ! ma9 or l9e circuit !refrom4 ,at any giv5 po9t 9 ?is circuit at or ne> :i* x is desir$ to obta9 direct curr5ts1 ! circuit ,b is divid$ into two pa?s or bran*es ,c ,d4 ,9 ea* ( ^! bran*es is plac$ an electrical g5]ator1 :i* = ! pres5t we w assume produces direct or cont9u\s curr5ts4 ,! direction ( ! curr5t ?us produc$ is opposite 9 "o bran* to t ( ! curr5t 9 ! o!r bran*1 or1 consid]+ ! two bran*es z =m+ a clos$ circuit1 ! g5]ators ,e ,f are connect$ up 9 s]ies !re91 "o g5]ator 9 ea* "p or half ( ! circuit4 ,! electromotive =ce ( ! curr5t s\rces ,e & ,f may be equal to or high] or l[] ?an ! electromotive =ces 9 ! bran*es ,c ,d1 or betwe5 ! po9ts ,x & ,y ( ! circuit ,b ,b4 ,if equal1 x is evid5t t curr5t waves ( "o sign w be oppos$ 9 "o bran* & assi/$ 9 ! o!r to su* an ext5t t all ! waves ( "o sign w pass ov] "o bran* & ^? ( opposite sign ov] ! o!r4 ,if1 on ! o!r h&1 ! electromotive =ce ( ! s\rces ,e ,f be l[] ?an t betwe5 ,x & ,y1 ! curr5ts 9 bo? bran*es w be alt]nat+1 b ! waves ( "o sign w prepond]ate4 ,"o ( ! g5]ators or s\rces ( curr5t ,e or ,f may be disp5s$ )2 b x is pref]able to employ bo?1 if !y (f] an appreciable resi/ance1 z ! two bran*es w be !reby bett] balanc$4 ,! translat+ or o!r devices to be act$ ^u by ! curr5t are designat$ by ! lett]s ,g1 & !y are ins]t$ 9 ! bran*es ,c ,d 9 any desir$ mann]2 b 9 ord] to bett] pres]ve an ev5 balance betwe5 ! bran*es due reg>d %\ld1 ( c\rse1 be _h to ! numb] & "* ( ! devices4 ,illu/ration3 ,,fig4 #bba4 ,figs4 #bba1 #bbb1 #bbc1 & #bbd illu/rate :at may t]m$ electro-magnetic devices = accompli%+ a simil> result--t is to say1 in/ead ( produc+ directly by a g5]ator an electromotive =ce 9 ea* bran* ( ! circuit1 ,mr4 ,tesla e/abli%es a field or fields ( =ce & leads ! bran*es ?r\gh ! same 9 su* mann] t an active opposition ( opposite effect or direction w be develop$ !re9 by ! passage1 or t5d5cy to pass1 ( ! alt]nations ( curr5t4 ,9 ,fig4 #bba1 = example1 ,a is ! g5]ator ( alt]nat+ curr5ts1 ,b ,b ! l9e circuit1 & ,c ,d ! bran*es ov] :i* ! alt]nat+ curr5ts are direct$4 ,9 ea* bran* is includ$ ! second>y ( a trans=m] or induction coil1 :i*1 s9ce !y correspond 9 _! functions to ! batt]ies ( ! previ\s figure1 are designat$ by ! lett]s ,e ,f4 ,! prim>ies ,h ,h' ( ! induction coils or trans=m]s are connect$ ei!r 9 p>allel or s]ies ) a s\rce ( direct or cont9u\s curr5ts ,i1 & ! numb] ( convolutions is s calculat$ = ! /r5g? ( ! curr5t f ,i t ! cores ,j ,j' w be saturat$4 ,! connections are su* t ! conditions 9 ! two trans=m]s are ( opposite "*--t is to say1 ! arrangem5t is su* t a curr5t wave or impulse correspond+ 9 direction ) t ( ! direct curr5t 9 "o prim>y1 z ,h1 is ( opposite direction to t 9 ! o!r prim>y ,h'4 ,x ?us results t :ile "o second>y (f]s a resi/ance or opposition to ! passage ?r\gh x ( a wave ( "o sign1 ! o!r second>y simil>ly opposes a wave ( opposite sign4 ,9 consequ5ce1 ! waves ( "o sign w1 to a great] or less ext5t1 pass by way ( "o bran*1 :ile ^? ( opposite sign 9 l mann] pass ov] ! o!r bran*4 ,9 lieu ( saturat+ ! prim>ies by a s\rce ( cont9u\s curr5t1 we may include ! prim>ies 9 ! bran*es ,c ,d1 respectively1 & p]iodically %ort-circuit by any suitable me*anical devices--su* z an ord9>y revolv+ commutator--_! second>ies4 ,x w be und]/ood1 ( c\rse1 t ! rotation & action ( ! commutator mu/ be 9 syn*ronism or 9 prop] accord ) ! p]iods ( ! alt]nations 9 ord] to secure ! desir$ results4 ,su* a disposition is repres5t$ diagrammatically 9 ,fig4 #bbb4 ,correspond+ to ! previ\s figures1 ,a is ! g5]ator ( alt]nat+ curr5ts1 ,b ,b ! l9e1 & ,c ,d ! two bran*es = ! direct curr5ts4 ,9 bran* ,c are includ$ two prim>y coils ,e ,e'1 & 9 bran* ,d are two simil> prim>ies ,f ,f' ,! correspond+ second>ies = ^! coils & :i* are on ! same subdivid$ cores ,j or ,j'1 are 9 circuits ! t]m9als ( :i* connect to opposite segm5ts ,k ,k'1 & ,l ,l'1 respectively1 ( a commutator4 ,bru%es b b be> ^u ! commutator & alt]nately %ort-circuit ! plates ,k & ,k'1 & ,l & ,l'1 ?r\gh a connection c4 ,x is obvi\s t ei!r ! magnets & commutator1 or ! bru%es1 may revolve4 ,illu/ration3 ,,fig4 #bbb4 ,! op]ation w be und]/ood f a consid]ation ( ! effects ( clos+ or %ort-circuit+ ! second>ies4 ,= example1 if at ! in/ant :5 a giv5 wave ( curr5t passes1 "o set ( second>ies be %ort-circuit$1 ne>ly all ! curr5t fl[s ?r\gh ! correspond+ prim>ies2 b ! second>ies ( ! o!r bran* be+ op5-circuit$1 ! self-induction 9 ! prim>ies is highe/1 & h5ce little or no curr5t w pass ?r\gh t bran*4 ,if1 z ! curr5t alt]nates1 ! second>ies ( ! two bran*es are alt]nately %ort-circuit$1 ! result w be t ! curr5ts ( "o sign pass ov] "o bran* & ^? ( ! opposite sign ov] ! o!r4 ,! disadvantages ( ?is arrangem5t1 :i* w\ld seem to result f ! employm5t ( slid+ contacts1 are 9 reality v slight1 inasmu* z ! electromotive =ce ( ! second>ies may be made exce$+ly l[1 s t sp>k+ at ! bru%es is avoid$4 ,illu/ration3 ,,fig4 #bbc4 ,fig4 #bbc is a diagram1 p>tly 9 section1 ( ano!r plan ( c>ry+ out ! inv5tion4 ,! circuit ,b 9 ?is case is divid$1 z be=e1 & ea* bran* includes ! coils ( bo? ! fields & revolv+ armatures ( two induction devices4 ,! armatures ,o ,p are pref]ably m\nt$ on ! same %aft1 & are adju/$ relatively to "o ano!r 9 su* mann] t :5 ! self-induction 9 "o bran*1 z ,c1 is maximum1 9 ! o!r bran* ,d x is m9imum4 ,! armatures are rotat$ 9 syn*ronism ) ! alt]nations f ! s\rce ,a4 ,! w9d+ or position ( ! armature coils is su* t a curr5t 9 a giv5 direction pass$ ?r\gh bo? armatures w\ld e/abli% 9 "o1 poles simil> to ^? 9 ! adjac5t poles ( ! field1 & 9 ! o!r1 poles unlike ! adjac5t field poles1 z indicat$ by n n s s 9 ! diagram4 ,if ! l poles are pres5t$1 z %[n 9 circuit ,d1 ! condition is t ( a clos$ second>y ^u a prim>y1 or ! position ( lea/ inductive resi/ance2 h5ce a giv5 alt]nation ( curr5t w pass ma9ly ?r\gh ,d4 ,a half revolution ( ! armatures produces an opposite effect & ! succe$+ curr5t impulse passes ?r\gh ,c4 ,us+ ?is figure z an illu/ration1 x is evid5t t ! fields ,n ,m may be p]man5t magnets or indep5d5tly excit$ & ! armatures ,o ,p driv51 z 9 ! pres5t case1 s z to produce alt]nate curr5ts1 :i* w set up alt]nately impulses ( opposite direction 9 ! two bran*es ,d ,c1 :i* 9 su* case w\ld include ! armature circuits & translat+ devices only4 ,9 ,fig4 #bbd a plan alt]native ) t %[n 9 ,fig4 #bbb is illu/rat$4 ,9 ! previ\s case illu/rat$1 ea* bran* ,c & ,d conta9$ "o or m prim>y coils1 ! second>ies ( :i* 7 p]iodically %ort circuit$ 9 syn*ronism ) ! alt]nations ( curr5t f ! ma9 s\rce ,a1 & = ?is purpose a commutator 0 employ$4 ,! latt] may1 h[ev]1 be disp5s$ ) & an armature ) a clos$ coil sub/itut$4 ,illu/ration3 ,,fig4 #bbd4 ,ref]r+ to ,fig4 #bbd 9 "o ( ! bran*es1 z ,c1 are two coils ,m'1 w\nd on lam9at$ cores1 & 9 ! o!r bran*es ,d are simil> coils ,n'4 ,a subdivid$ or lam9at$ armature ,o'1 c>ry+ a clos$ coil ,r'1 is rotatably support$ betwe5 ! coils ,m' ,n'1 z %[n4 ,9 ! position %[n--t is1 ) ! coil ,r' p>allel ) ! convolutions ( ! prim>ies ,n' ,m'--practically ! :ole curr5t w pass ?r\gh bran* ,d1 because ! self-induction 9 coils ,m' ,m' is maximum4 ,if1 !re=e1 ! armature & coil be rotat$ at a prop] spe$ relatively to ! p]iods or alt]nations ( ! s\rce ,a1 ! same results are obta9$ z 9 ! case ( ,fig4 #bbb4 ,fig4 #bbe is an in/ance ( :at may be call$1 9 di/9ction to ! o!rs1 a magnetic means ( secur+ ! result4 ,v & ,w are two /rong p]man5t magnets provid$ ) armatures ,v' ,w'1 respectively4 ,! armatures are made ( ?9 lam9ae ( s(t iron or /eel1 & ! am\nt ( magnetic metal :i* !y conta9 is s calculat$ t !y w be fully or ne>ly saturat$ by ! magnets4 ,ar\nd ! armatures are coils ,e ,f1 conta9$1 respectively1 9 ! circuits ,c & ,d4 ,! connections & electrical conditions 9 ?is case are simil> to ^? 9 ,fig4 #bba1 except t ! curr5t s\rce ( ,i1 ,fig4 #bba1 is disp5s$ ) & ! saturation ( ! core ( coils ,e ,f obta9$ f ! p]man5t magnets4 ,illu/ration3 ,,fig4 #bbe4 ,! previ\s illu/rations h all %[n ! two bran*es or pa?s conta9+ ! translat+ or induction devices z 9 d]ivation "o to ! o!r2 b ?is is n always necess>y4 ,= example1 9 ,fig4 #bbf1 ,a is an alt]nat+-curr5t g5]ator2 ,b ,b1 ! l9e wires or circuit4 ,at any giv5 po9t 9 ! circuit let u =m two pa?s1 z ,d ,d'1 & at ano!r po9t two pa?s1 z ,c ,c'4 ,ei!r pair or gr\p ( pa?s is simil> to ! previ\s dispositions ) ! electrical s\rce or induction device 9 "o bran* only1 :ile ! two gr\ps tak5 toge!r =m ! obvi\s equival5t ( ! cases 9 :i* an induction device or g5]ator is includ$ 9 bo? bran*es4 ,9 "o ( ! pa?s1 z ,d1 are includ$ ! devices to be op]at$ by ! curr5t4 ,9 ! o!r bran*1 z ,d'1 is an induction device t opposes ! curr5t impulses ( "o direction & directs !m ?r\gh ! bran* ,d4 ,s1 also1 9 bran* ,c are translat+ devices ,g1 & 9 bran* ,c' an induction device or its equival5t t div]ts ?r\gh ,c impulses ( opposite direction to ^? div]t$ by ! device 9 bran* ,d'4 ,! diagram %[s a special =m ( induction device = ?is purpose4 ,j ,j' are ! cores1 =m$ ) pole-pieces1 ^u :i* are w\nd ! coils ,m ,n4 ,betwe5 ^! pole-pieces are m\nt$ at "r angles to "o ano!r ! magnetic armatures ,o ,p1 pref]ably m\nt$ on ! same %aft & design$ to be rotat$ 9 syn*ronism ) ! alt]nations ( curr5t4 ,:5 "o ( ! armatures is 9 l9e ) ! poles or 9 ! position occupi$ by armature ,p1 ! magnetic circuit ( ! induction device is practically clos$2 h5ce !re w be ! greate/ opposition to ! passage ( a curr5t ?r\gh coils ,n ,n4 ,! alt]nation w !re=e pass by way ( bran* ,d4 ,at ! same "t1 ! magnetic circuit ( ! o!r induction device be+ brok5 by ! position ( ! armature ,o1 !re w be less opposition to ! curr5t 9 coils ,m1 :i* w %unt ! curr5t f bran* ,c4 ,a rev]sal ( ! curr5t be+ att5d$ by a %ift+ ( ! armatures1 ! opposite effect is produc$4 ,illu/ration3 ,,fig4 #bbf4 ,o!r modifications ( ^! me?ods are possible1 b ne$ n be po9t$ out4 ,9 all ^! plans1 x w be obs]v$1 !re is develop$ 9 "o or all ( ^! bran*es ( a circuit f a s\rce ( alt]nat+ curr5ts1 an active 7z di/+ui%$ f a dead7 resi/ance or opposition to ! curr5ts ( "o sign1 = ! purpose ( div]t+ ! curr5ts ( t sign ?r\gh ! o!r or ano!r pa?1 b p]mitt+ ! curr5ts ( opposite sign to pass )\t sub/antial opposition4 ,:e!r ! division ( ! curr5ts or waves ( curr5t ( opposite sign be effect$ ) absolute precision or n is immat]ial1 s9ce x w be suffici5t if ! waves are only p>tially div]t$ or direct$1 = 9 su* case ! prepond]at+ influ5ce 9 ea* bran* ( ! circuit ( ! waves ( "o sign secures ! same practical results 9 _m if n all respects z ?\gh ! curr5t 7 direct & cont9u\s4 ,an alt]nat+ & a direct curr5t h be5 comb9$ s t ! waves ( "o direction or sign 7 p>tially or :olly ov]come by ! direct curr5t2 b by ?is plan only "o set ( alt]nations are utiliz$1 :]eas by ! sy/em j describ$ ! entire curr5t is r5d]$ available4 ,by obvi\s applications ( ?is discov]y ,mr4 ,tesla is enabl$ to produce a self-excit+ alt]nat+ dynamo1 or to op]ate direct curr5t met]s on alt]nat+-curr5t circuits or to run v>i\s devices--su* z arc lamps--by direct curr5ts 9 ! same circuit ) inc&esc5t lamps or o!r devices op]at$ by alt]nat+ curr5ts4 ,x w be obs]v$ t if an int]mitt5t c\nt] or oppos+ =ce be develop$ 9 ! bran*es ( ! circuit & ( high] electromotive =ce ?an t ( ! g5]ator1 an alt]nat+ curr5t w result 9 ea* bran*1 ) ! waves ( "o sign prepond]at+1 :ile a con/antly or uni=mly act+ opposition 9 ! bran*es ( high] electromotive =ce ?an ! g5]ator w\ld produce a pulsat+ curr5t1 :i* conditions w\ld be1 "u "s circum/ances1 ! equival5t ( ^? describ$4 ,,*apt] ,,xxxiv4 ,,cond5s]s ,,) ,,plates ,,9 ,,oil4 ,illu/ration3 ,,fig4 #bbg4 ,illu/ration3 ,,fig4 #bbh4 ,9 exp]im5t+ ) curr5ts ( high frequ5cy & high pot5tial1 ,mr4 ,tesla has f\nd t insulat+ mat]ials su* z glass1 mica1 & 9 g5]al ^? bodies :i* possess ! highe/ specific inductive capacity1 are inf]ior z insulators 9 su* devices :5 curr5ts ( ! k9d describ$ are employ$ comp>$ ) ^? possess+ high insulat+ p[]1 toge!r ) a small] specific inductive capacity2 & he has also f\nd t x is v desirable to exclude all gase\s matt] f ! app>atus1 or any access ( ! same to ! electrifi$ surfaces1 9 ord] to prev5t heat+ by molecul> bomb>dm5t & ! loss or injury consequ5t !reon4 ,he has !re=e devis$ a me?od to accompli% ^! results & produce highly effici5t & reliable cond5s]s1 by us+ oil z ! dielectric#aa4 ,! plan admits ( a p>ticul> con/ruction ( cond5s]1 9 :i* ! di/ance betwe5 ! plates is adju/able1 & ( :i* he takes advantage4 #aa ,mr4 ,tesla's exp]im5ts1 z ! c>eful read] ( 8 ?ree lectures w p]ceive1 h reveal$ a v important fact :i* is tak5 advantage ( 9 ?is inv5tion4 ,namely1 he has %[n t 9 a cond5s] a consid]able am\nt ( en]gy may be wa/$1 & ! cond5s] may break d[n m]ely because gase\s matt] is pres5t betwe5 ! surfaces4 ,a numb] ( exp]im5ts are describ$ 9 ! lectures1 :i* br+ out ?is fact =cibly & s]ve z a guide 9 ! op]ation ( high t5sion app>atus4 ,b besides be>+ ^u ?is po9t1 ^! exp]im5ts also ?r[ a light ^u inve/igations ( a purely sci5tific nature & expla9 n[ ! lack ( h>mony among ! obs]vations ( v>i\s inve/igators4 ,mr4 ,tesla %[s t 9 a fluid su* z oil ! losses are v small z comp>$ ) ^? incurr$ 9 a gas4 ,9 ! accompany+ illu/rations1 ,fig4 #bbg is a section ( a cond5s] con/ruct$ 9 accordance ) ?is pr9ciple & hav+ /ation>y plates2 & ,fig4 #bbh is a simil> view ( a cond5s] ) adju/able plates4 ,any suitable box or receptacle ,a may be us$ to conta9 ! plates or armatures4 ,^! latt] are designat$ by ,b & ,c & are connect$1 respectively1 to t]m9als ,d & ,e1 :i* pass out ?r\gh ! sides ( ! case4 ,! plates ord9>ily are sep>at$ by /rips ( por\s insulat+ mat]ial ,f1 :i* are us$ m]ely = ! purpose ( ma9ta9+ !m 9 position4 ,! space )9 ! c is fill$ ) oil ,g4 ,su* a cond5s] w prove highly effici5t & w n become heat$ or p]man5tly injur$4 ,9 _m cases x is desirable to v>y or adju/ ! capacity ( a cond5s]1 & ?is is provid$ = by secur+ ! plates to adju/able supports--z1 = example1 to rods ,h--pass+ ?r\gh /uff+ boxes ,k 9 ! sides ( case ,a & furni%$ ) nuts ,l1 ! ends ( ! rods be+ ?read$ = engagem5t ) ! nuts4 ,x is well kn[n t oils possess insulat+ prop]ties1 & x has be5 a common practice to int]pose a body ( oil betwe5 two conductors = purposes ( insulation2 b ,mr4 ,tesla believes he has discov]$ peculi> prop]ties 9 oils :i* r5d] !m v valuable 9 ?is p>ticul> =m ( device4 ,,*apt] ,,xxxv4 ,,electrolytic ,,regi/]+ ,,met]4 ,an +5i\s =m ( electrolytic met] attributable to ,mr4 ,tesla is "o 9 :i* a conductor is imm]s$ 9 a solution1 s arrang$ t metal may be deposit$ f ! solution or tak5 away 9 su* a mann] t ! electrical resi/ance ( ! conductor is v>i$ 9 a def9ite proportion to ! /r5g? ( ! curr5t ! en]gy ( :i* is to be comput$1 :]eby ?is v>iation 9 resi/ance s]ves z a measure ( ! en]gy & also may actuate regi/]+ me*anism1 :5ev] ! resi/ance rises above or falls bel[ c]ta9 limits4 ,9 c>ry+ out ?is idea ,mr4 ,tesla employs an electrolytic cell1 ?r\gh :i* ext5d two conductors p>allel & 9 close proximity to ea* o!r4 ,^! conductors he connects 9 s]ies ?r\gh a resi/ance1 b 9 su* mann] t !re is an equal diff]5ce ( pot5tial betwe5 !m ?r\gh\t _! entire ext5t4 ,! free ends or t]m9als ( ! conductors are connect$ ei!r 9 s]ies 9 ! circuit supply+ ! curr5t to ! lamps or o!r devices1 or 9 p>allel to a resi/ance 9 ! circuit & 9 s]ies ) ! curr5t consum+ devices4 ,"u su* circum/ances a curr5t pass+ ?r\gh ! conductors e/abli%es a diff]5ce ( pot5tial betwe5 !m :i* is proportional to ! /r5g? ( ! curr5t1 9 consequ5ce ( :i* !re is a leakage ( curr5t f "o conductor to ! o!r across ! solution4 ,! /r5g? ( ?is leakage curr5t is proportional to ! diff]5ce ( pot5tial1 &1 !re=e1 9 proportion to ! /r5g? ( ! curr5t pass+ ?r\gh ! conductors4 ,moreov]1 z !re is a con/ant diff]5ce ( pot5tial betwe5 ! two conductors ?r\gh\t ! entire ext5t t is expos$ to ! solution1 ! curr5t d5sity ?r\gh su* solution is ! same at all correspond+ po9ts1 & h5ce ! deposit is uni=m along ! :ole ( "o ( ! conductors1 :ile ! metal is tak5 away uni=mly f ! o!r4 ,! resi/ance ( "o conductor is by ?is means dim9i%$1 :ile t ( ! o!r is increas$1 bo? 9 proportion to ! /r5g? ( ! curr5t pass+ ?r\gh ! conductors4 ,f su* v>iation 9 ! resi/ance ( ei!r or bo? ( ! conductors =m+ ! positive & negative electrodes ( ! cell1 ! curr5t en]gy exp5d$ may be readily comput$4 ,figs4 #bbi & #bcj illu/rate two =ms ( su* a met]4 ,illu/ration3 ,,fig4 #bbi4 ,9 ,fig4 #bbi ,g designates a direct-curr5t g5]ator4 ,l ,l are ! conductors ( ! circuit ext5d+ !refrom4 ,a is a tube ( glass1 ! ends ( :i* are seal$1 z by means ( insulat+ plugs or caps ,b ,b4 ,c ,c' are two conductors ext5d+ ?r\gh ! tube ,a1 _! ends pass+ out ?r\gh ! plugs ,b to t]m9als !reon4 ,^! conductors may be corrugat$ or =m$ 9 o!r prop] ways to (f] ! desir$ electrical resi/ance4 ,r is a resi/ance connect$ 9 s]ies ) ! two conductors ,c ,c'1 :i* by _! free t]m9als are connect$ up 9 circuit ) "o ( ! conductors ,l4 ,! me?od ( us+ ?is device & comput+ by means !re( ! en]gy ( ! curr5t w be readily und]/ood4 ,fir/1 ! resi/ances ( ! two conductors ,c ,c'1 respectively1 are accurately measur$ & not$4 ,!n a kn[n curr5t is pass$ ?r\gh ! in/rum5t = a giv5 "t1 & by a second measurem5t ! increase & dim9ution ( ! resi/ances ( ! two conductors are respectively tak54 ,f ^! data ! con/ant is obta9$--t is to say1 = example1 ! increase ( resi/ance ( "o conductor or ! dim9ution ( ! resi/ance ( ! o!r p] lamp h\r4 ,^! two measurem5ts evid5tly s]ve z a *eck1 s9ce ! ga9 ( "o conductor %\ld equal ! loss ( ! o!r4 ,a fur!r *eck is af=d$ by measur+ bo? wires 9 s]ies ) ! resi/ance1 9 :i* case ! resi/ance ( ! :ole %\ld rema9 con/ant4 ,illu/ration3 ,,fig4 #bcj4 ,9 ,fig4 #bcj ! conductors ,c ,c' are connect$ 9 p>allel1 ! curr5t device at ,x pass+ 9 "o bran* fir/ ?r\gh a resi/ance ,r' & !n ?r\gh conductor ,c1 :ile on ! o!r bran* x passes fir/ ?r\gh conductor ,c'1 & !n ?r\gh resi/ance ,r''4 ,! resi/ances ,r' ,r'' are equal1 z also are ! resi/ances ( ! conductors ,c ,c'4 ,x is1 moreov]1 pref]able t ! respective resi/ances ( ! conductors ,c ,c' %\ld be a kn[n & conv5i5t fraction ( ! coils or resi/ances ,r' ,r''4 ,x w be obs]v$ t 9 ! arrangem5t %[n 9 ,fig4 #bcj !re is a con/ant pot5tial diff]5ce betwe5 ! two conductors ,c ,c' ?r\gh\t _! entire l5g?4 ,x w be se5 t 9 bo? cases illu/rat$1 ! proportionality ( ! increase or decrease ( resi/ance to ! curr5t /r5g? w always be pres]v$1 = :at "o conductor ga9s ! o!r loses1 & ! resi/ances ( ! conductors ,c ,c' be+ small z comp>$ ) ! resi/ances 9 s]ies ) !m4 ,x w be und]/ood t aft] ea* measurem5t or regi/ration ( a giv5 v>iation ( resi/ance 9 "o or bo? conductors1 ! direction ( ! curr5t %\ld be *ang$ or ! in/rum5t rev]s$1 s t ! deposit w be tak5 f ! conductor :i* has ga9$ & add$ to t :i* has lo/4 ,?is pr9ciple is capable ( _m modifications4 ,= in/ance1 s9ce !re is a section ( ! circuit--to wit1 ! conductor ,c or ,c'--t v>ies 9 resi/ance 9 proportion to ! curr5t /r5g?1 su* v>iation may be utiliz$1 z is done 9 _m analog\s cases1 to effect ! op]ation ( v>i\s automatic devices1 su* z regi/]s4 ,x is bett]1 h[ev]1 = ! sake ( simplicity to compute ! en]gy by measurem5ts ( resi/ance4 ,! *ief advantages ( ?is arrangem5t are1 fir/1 t x is possible to read (f directly ! am\nt ( ! en]gy exp5d$ by means ( a prop]ly con/ruct$ ohm-met] & )\t resort+ to weigh+ ! deposit2 secondly x is n necess>y to employ %unts1 = ! :ole ( ! curr5t to be measur$ may be pass$ ?r\gh ! in/rum5t2 ?ird1 ! accuracy ( ! in/rum5t & correctness ( ! indications are b slightly affect$ by *anges 9 temp]ature4 ,x is also said t su* met]s h ! m]it ( sup]ior economy & compactness1 z well z ( *eapness 9 con/ruction4 ,electrolytic met]s seem to ne$ e auxili>y advantage to make !m p]man5tly popul> & successful1 no matt] h[ mu* +5uity may be %[n 9 _! design4 ,,*apt] ,,xxxvi4 ,,!rmo-,,magnetic ,,motors ,,& ,,pyro-,,magnetic ,,g5]ators4 ,no electrical inv5tor ( ! pres5t day deal+ ) ! problems ( light & p[] consid]s t he has done himself or 8 opportunities ju/ice until he has attack$ ! subject ( !rmo-magnetism4 ,z f> back z ! beg9n+ ( ! sev5te5? c5tury x 0 %[n by ,dr4 ,william ,gilb]t1 ! fa!r ( mod]n electricity1 t a load/one or iron b> :5 heat$ to r$ness loses its magnetism2 & s9ce t "t ! influ5ce ( heat on ! magnetic metals has be5 inve/igat$ frequ5tly1 ?\gh n ) any mat]ial or practical result4 ,= a man ( ,mr4 ,tesla's inv5tive ability1 ! problems 9 ?is field h naturally _h no small fasc9ation1 & ?\gh he has b glanc$ at !m1 x is to be hop$ he may f9d "t to pursue ! /udy deep] & fur!r4 ,= su* z he1 ! inve/igation mu/ und\bt$ly be> fruit4 ,mean:ile he has work$ out "o or two op]ative devices wor?y ( note4#ab ,he obta9s me*anical p[] by a reciprocat+ action result+ f ! jo9t op]ations ( heat1 magnetism1 & a spr+ or weight or o!r =ce--t is to say he subjects a body magnetiz$ by induction or o!rwise to ! action ( heat until ! magnetism is suffici5tly neutraliz$ to all[ a weight or spr+ to give motion to ! body & less5 ! action ( ! heat1 s t ! magnetism may be suffici5tly re/or$ to move ! body 9 ! opposite direction1 & aga9 subject ! same to ! demagnetiz+ p[] ( ! heat4 #ab ,x w1 ( c\rse1 be inf]r$ f ! nature ( ^! devices t ! vibration obta9$ 9 ?is mann] is v sl[ ow+ to ! inability ( ! iron to foll[ rapid *anges 9 temp]ature4 ,9 an int]view ) ,mr4 ,tesla on ?is subject1 ! compil] le>n$ ( an exp]im5t :i* w int]e/ /ud5ts4 ,a simple horse%oe magnet is tak5 & a piece ( %eet iron b5t 9 ! =m ( an ,l is br\ght 9 contact ) "o ( ! poles & plac$ 9 su* a position t x is kept 9 ! attraction ( ! opposite pole delicately susp5d$4 ,a _s lamp is plac$ "u ! %eet iron piece & :5 ! iron is heat$ to a c]ta9 temp]ature x is easily set 9 vibration oscillat+ z rapidly z #djj to #ejj times a m9ute4 ,! exp]im5t is v easily p]=m$ & is int]e/+ pr9cipally on acc\nt ( ! v rapid rate ( vibration4 ,use is made ( ei!r an electro-magnet or a p]man5t magnet1 & ! heat is direct$ aga9/ a body t is magnetiz$ by induction1 r ?an directly aga9/ a p]man5t magnet1 !reby avoid+ ! loss ( magnetism t might result 9 ! p]man5t magnet by ! action ( heat4 ,mr4 ,tesla also provides = less5+ ! volume ( ! heat or = int]cept+ ! same dur+ t portion ( ! reciprocation 9 :i* ! cool+ action takes place4 ,9 ! diagrams are %[n "s ( ! num]\s arrangem5ts t may be made use ( 9 c>ry+ out ?is idea4 ,9 all ( ^! figures ! magnet-poles are m>k$ ,n ,s1 ! armature ,a1 ! ,buns5 burn] or o!r s\rce ( heat ,h1 ! axis ( motion ,m1 & ! spr+ or ! equival5t !re(--namely1 a weight--is m>k$ ,w4 ,illu/ration3 ,,fig4 #bcb4 ,illu/ration3 ,,fig4 #bca4 ,illu/ration3 ,,fig4 #bcc4 ,9 ,fig4 #bca ! p]man5t magnet ,n is connect$ ) a frame1 ,f1 support+ ! axis ,m1 f :i* ! arm ,p hangs1 & at ! l[] end ( :i* ! armature ,a is support$4 ,! /ops #b & #c limit ! ext5t ( motion1 & ! spr+ ,w t5ds to draw ! armature ,a away f ! magnet ,n4 ,x w n[ be und]/ood t ! magnetism ( ,n is suffici5t to ov]come ! spr+ ,w & draw ! armature ,a t[>d ! magnet ,n4 ,! heat act+ ^u ! armature ,a neutralizes its induc$ magnetism suffici5tly = ! spr+ ,w to draw ! armature ,a away f ! magnet ,n & also f ! heat at ,h4 ,! armature n[ cools1 & ! attraction ( ! magnet ,n ov]comes ! spr+ ,w & draws ! armature ,a back aga9 above ! burn] ,h1 s t ! same is aga9 heat$ & ! op]ations are repeat$4 ,! reciprocat+ movem5ts ?us obta9$ are employ$ z a s\rce ( me*anical p[] 9 any desir$ mann]4 ,usually a connect+-rod to a crank ^u a fly-:eel %aft w\ld be made use (1 z indicat$ 9 ,fig4 #bdj4 ,illu/ration3 ,,fig4 #bcd4 ,illu/ration3 ,,fig4 #bcf4 ,illu/ration3 ,,fig4 #bce4 ,fig4 #bcb repres5ts ! same p>ts z be=e describ$2 b an electro-magnet is illu/rat$ 9 place ( a p]man5t magnet4 ,! op]ations1 h[ev]1 are ! same4 ,9 ,fig4 #bcc are %[n ! same p>ts z 9 ,figs4 #bca & #bcb1 b !y are diff]5tly arrang$4 ,! armature ,a1 in/ead ( sw++1 is /ation>y & held by arm ,p'1 & ! core ,n ,s ( ! electro-magnet is made to sw+ )9 ! helix ,q1 ! core be+ susp5d$ by ! arm ,p f ! pivot ,m4 ,a %ield1 ,r1 is connect$ ) ! magnet-core & sw+s ) x1 s t aft] ! heat has demagnetiz$ ! armature ,a to su* an ext5t t ! spr+ ,w draws ! core ,n ,s away f ! armature ,a1 ! %ield ,r comes betwe5 ! flame ,h & armature ,a1 !reby int]cept+ ! action ( ! heat & all[+ ! armature to cool1 s t ! magnetism1 aga9 prepond]at+1 causes ! movem5t ( ! core ,n ,s t[>d ! armature ,a & ! removal ( ! %ield ,r f above ! flame1 s t ! heat aga9 acts to less5 or neutralize ! magnetism4 ,a rot>y or o!r movem5t may be obta9$ f ?is reciprocation4 ,fig4 #bcd corresponds 9 e respect ) ,fig4 #bcc1 except t a p]man5t horse%oe-magnet1 ,n ,s is repres5t$ z tak+ ! place ( ! electro-magnet 9 ,fig4 #bcc4 ,9 ,fig4 #bce is %[n a helix1 ,q1 ) an armature adapt$ to sw+ t[>d or f ! helix4 ,9 ?is case !re may be a s(t-iron core 9 ! helix1 or ! armature may assume ! =m ( a sol5oid core1 !re be+ no p]man5t core )9 ! helix4 ,illu/ration3 ,,fig4 #bcg4 ,illu/ration3 ,,fig4 #bch4 ,illu/ration3 ,,fig4 #bci4 ,fig4 #bcf is an end view1 & ,fig4 #bcg a plan view1 illu/rat+ ! me?od z appli$ to a sw++ armature1 ,a1 & a /ation>y p]man5t magnet1 ,n ,s4 ,9 ?is in/ance ,mr4 ,tesla applies ! heat to an auxili>y armature or keep]1 ,t1 :i* is adjac5t to & pref]ably 9 direct contact ) ! magnet4 ,?is armature ,t1 9 ! =m ( a plate ( %eet-iron1 ext5ds across f "o pole to ! o!r & is ( suffici5t section to practically =m a keep] = ! magnet1 s t :5 ! armature ,t is cool ne>ly all ! l9es ( =ce pass ov] ! same & v little free magnetism is exhibit$4 ,!n ! armature ,a1 :i* sw+s freely on ! pivots ,m 9 front ( ! poles ,n ,s1 is v little attract$ & ! spr+ ,w pulls ! same way f ! poles into ! position indicat$ 9 ! diagram4 ,! heat is direct$ ^u ! iron plate ,t at "s di/ance f ! magnet1 s z to all[ ! magnet to keep comp>atively cool4 ,?is heat is appli$ b5ea? ! plate by means ( ! burn]s ,h1 & !re is a connection f ! armature ,a or its pivot to ! gas-cock #f1 or o!r device = regulat+ ! heat4 ,! heat act+ ^u ! middle portion ( ! plate ,t1 ! magnetic conductivity ( ! heat$ portion is dim9i%$ or de/roy$1 & a great numb] ( ! l9es ( =ce are deflect$ ov] ! armature ,a1 :i* is n[ p[]fully attract$ & drawn into l9e1 or ne>ly s1 ) ! poles ,n ,s4 ,9 s do+ ! cock #f is ne>ly clos$ & ! plate ,t cools1 ! l9es ( =ce are aga9 deflect$ ov] ! same1 ! attraction ex]t$ ^u ! armature ,a is dim9i%$1 & ! spr+ ,w pulls ! same away f ! magnet into ! position %[n by full l9es1 & ! op]ations are repeat$4 ,! arrangem5t %[n 9 ,fig4 #bcf has ! advantages t ! magnet & armature are kept cool & ! /r5g? ( ! p]man5t magnet is bett] pres]v$1 z ! magnetic circuit is con/antly clos$4 ,9 ! plan view1 ,fig4 #bch1 is %[n a p]man5t magnet & keep] plate1 ,t1 simil> to ^? 9 ,figs4 #bcf & #bcg1 ) ! burn]s ,h = ! gas b5ea? ! same2 b ! armature is pivot$ at "o end to "o pole ( ! magnet & ! o!r end sw+s t[>d & f ! o!r pole ( ! magnet4 ,! spr+ ,w acts aga9/ a lev] arm t projects f ! armature1 & ! supply ( heat has to be p>tly cut (f by a connection to ! sw++ armature1 s z to less5 ! heat act+ ^u ! keep] plate :5 ! armature ,a has be5 attract$4 ,illu/ration3 ,,fig4 #bdj4 ,illu/ration3 ,,fig4 #bda4 ,fig4 #bci is simil> to ,fig4 #bch1 except t ! keep] ,t is n made use ( & ! armature itself sw+s into & out ( ! range ( ! int5se action ( ! heat f ! burn] ,h4 ,fig4 #bdj is a diagram simil> to ,fig4 #bca1 except t 9 place ( us+ a spr+ & /ops1 ! armature is %[n z connect$ by a l9k1 to ! crank ( a fly-:eel1 s t ! fly-:eel w be revolv$ z rapidly z ! armature c be heat$ & cool$ to ! necess>y ext5t4 ,a spr+ may be us$ 9 addition1 z 9 ,fig4 #bca4 ,9 ,fig4 #bda ! armatures ,a ,a are connect$ by a l9k1 s t "o w be heat+ :ile ! o!r is cool+1 & ! attraction ex]t$ to move ! cool$ armature is avail$ ( to draw away ! heat$ armature in/ead ( us+ a spr+4 ,mr4 ,tesla has also devot$ 8 att5tion to ! developm5t ( a pyromagnetic g5]ator ( electricity#ac bas$ ^u ! foll[+ laws3 ,fir/1 t electricity or electrical en]gy is develop$ 9 any conduct+ body by subject+ su* body to a v>y+ magnetic influ5ce2 & second1 t ! magnetic prop]ties ( iron or o!r magnetic sub/ance may be p>tially or entirely de/roy$ or caus$ to disappe> by rais+ x to a c]ta9 temp]ature1 b re/or$ & caus$ to reappe> by aga9 l[]+ its temp]ature to a c]ta9 degree4 ,^! laws may be appli$ 9 ! production ( electrical curr5ts 9 _m ways1 ! pr9ciple ( :i* is 9 all cases ! same1 viz41 to subject a conductor to a v>y+ magnetic influ5ce1 produc+ su* v>iations by ! application ( heat1 or1 m /rictly speak+1 by ! application or action ( a v>y+ temp]ature ^u ! s\rce ( ! magnetism4 ,?is pr9ciple ( op]ation may be illu/rat$ by a simple exp]im5t3 ,place end to end1 & pref]ably 9 actual contact1 a p]man5tly magnetiz$ /eel b> & a /rip or b> ( s(t iron4 ,ar\nd ! end ( ! iron b> or plate w9d a coil ( insulat$ wire4 ,!n apply to ! iron betwe5 ! coil & ! /eel b> a flame or o!r s\rce ( heat :i* w be capable ( rais+ t portion ( ! iron to an orange r$1 or a temp]ature ( ab\t #fjj deg4 c5tigrade4 ,:5 ?is condition is rea*$1 ! iron some:at sudd5ly loses its magnetic prop]ties1 if x be v ?91 & ! same effect is produc$ z ?\gh ! iron _h be5 mov$ away f ! magnet or ! heat$ section _h be5 remov$4 ,?is *ange ( position1 h[ev]1 is accompani$ by a %ift+ ( ! magnetic l9es1 or1 9 o!r words1 by a v>iation 9 ! magnetic influ5ce to :i* ! coil is expos$1 & a curr5t 9 ! coil is ! result4 ,!n remove ! flame or 9 any o!r way r$uce ! temp]ature ( ! iron4 ,! l[]+ ( its temp]ature is accompani$ by a return ( its magnetic prop]ties1 & ano!r *ange ( magnetic conditions occurs1 accompani$ by a curr5t 9 an opposite direction 9 ! coil4 ,! same op]ation may be repeat$ indef9itely1 ! effect ^u ! coil be+ simil> to t :i* w\ld foll[ f mov+ ! magnetiz$ b> to & f ! end ( ! iron b> or plate4 #ac ,! *ief po9t to be not$ is t ,mr4 ,tesla attack$ ?is problem 9 a way :i* 01 f ! /&po9t ( !ory1 & t ( an eng9e]1 f> bett] ?an t f :i* "s e>li] trials 9 ?is direction />t$4 ,! enl>gem5t ( ^! ideas w be f\nd 9 ,mr4 ,tesla's "w on ! pyromagnetic g5]ator1 treat$ 9 ?is *apt]4 ,! *ief ef=t ( ! inv5tor 0 to economize ! heat1 :i* 0 accompli%$ by inclos+ ! iron 9 a s\rce ( heat well insulat$1 & by cool+ ! iron by means ( /eam1 utiliz+ ! /eam ov] aga94 ,! con/ruction also p]mits ( m rapid magnetic *anges p] unit ( "t1 mean+ l>g] output4 ,! device illu/rat$ bel[ is a means ( obta9+ ?is result1 ! features ( novelty 9 ! inv5tion be+1 fir/1 ! employm5t ( an artificial cool+ device1 &1 second1 inclos+ ! s\rce ( heat & t portion ( ! magnetic circuit expos$ to ! heat & artificially cool+ ! heat$ "p4 ,^! improvem5ts are applicable g5]ally to ! g5]ators con/ruct$ on ! plan above describ$--t is to say1 we may use an artificial cool+ device 9 conjunction ) a v>iable or v>i$ or uni=m s\rce ( heat4 ,illu/ration3 ,,fig4 #bdb4 ,illu/ration3 ,,fig4 #bdc4 ,fig4 #bdb is a c5tral v]tical longitud9al section ( ! complete app>atus & ,fig4 #bdc is a cross-section ( ! magnetic armature-core ( ! g5]ator4 ,let ,a repres5t a magnetiz$ core or p]man5t magnet ! poles ( :i* are bridg$ by an armature-core compos$ ( a cas+ or %ell ,b inclos+ a numb] ( holl[ iron tubes ,c4 ,ar\nd ?is core are w\nd ! conductors ,e ,e'1 to =m ! coils 9 :i* ! curr5ts are develop$4 ,9 ! circuits ( ^! coils are curr5t-consum+ devices1 z ,f ,f'4 ,d is a furnace or clos$ fire-box1 ?r\gh :i* ! c5tral portion ( ! core ,b ext5ds4 ,above ! fire is a boil] ,k1 conta9+ wat]4 ,! flue ,l f ! fire-box may ext5d up ?r\gh ! boil]4 ,g is a wat]-supply pipe1 & ,h is ! /eam-exhau/ pipe1 :i* communicates ) all ! tubes ,c 9 ! armature ,b1 s t /eam escap+ f ! boil] w pass ?r\gh ! tubes4 ,9 ! /eam-exhau/ pipe ,h is a valve ,v1 to :i* is connect$ ! lev] ,i1 by ! movem5t ( :i* ! valve is op5$ or clos$4 ,9 su* a case z ?is ! heat ( ! fire may be utiliz$ = o!r purposes aft] z mu* ( x z may be ne$$ has be5 appli$ to heat+ ! core ,b4 ,!re are special advantages 9 ! employm5t ( a cool+ device1 9 t ! metal ( ! core ,b is n s quickly oxidiz$4 ,moreov]1 ! diff]5ce betwe5 ! temp]ature ( ! appli$ heat & ( ! /eam1 air1 or :atev] gas or fluid be appli$ z ! cool+ m$ium1 may be increas$ or decreas$ at w1 :]eby ! rapidity ( ! magnetic *anges or fluctuations may be regulat$4 ,,*apt] ,,xxxvii4 ,,anti-,,sp>k+ ,,dynamo ,,bru% ,,& ,,commutator4 ,9 direct curr5t dynamos ( great electromotive =ce--su*1 = in/ance1 z ^? us$ = arc light+--:5 "o commutator b> or plate comes out ( contact ) ! collect+-bru% a sp>k is apt to appe> on ! commutator4 ,?is sp>k may be due to ! break ( ! complete circuit1 or to a %unt ( l[ resi/ance =m$ by ! bru% betwe5 two or m commutator-b>s4 ,9 ! fir/ case ! sp>k is m app>5t1 z !re is at ! mom5t :5 ! circuit is brok5 a dis*>ge ( ! magnets ?r\gh ! field helices1 produc+ a great sp>k or fla% :i* causes an un/eady curr5t1 rapid we> ( ! commutator b>s & bru%es1 & wa/e ( p[]4 ,! sp>k+ may be r$uc$ by v>i\s devices1 su* z provid+ a pa? = ! curr5t at ! mom5t :5 ! commutator segm5t or b> leaves ! bru%1 by %ort-circuit+ ! field-helices1 by increas+ ! numb] ( ! commutator-b>s1 or by o!r simil> means2 b all ^! devices are exp5sive or n fully available1 & seldom atta9 ! object desir$4 ,to prev5t ?is sp>k+ 9 a simple mann]1 ,mr4 ,tesla "s ye>s ago employ$ ) ! commutator-b>s & int]v5+ insulat+ mat]ial1 mica1 asbe/os pap] or o!r insulat+ & incombu/ible mat]ial1 arrang$ to be> on ! surface ( ! commutator1 ne> to & beh9d ! bru%4 ,9 ! draw+s1 ,fig4 #bdd is a section ( a commutator ) an asbe/os insulat+ device2 & ,fig4 #bde is a simil> view1 repres5t+ two plates ( mica ^u ! back ( ! bru%4 ,9 #bdd1 ,c repres5ts ! commutator & int]v5+ insulat+ mat]ial2 ,b ,b1 ! bru%es4 d d are %eets ( asbe/os pap] or o!r suitable non-conduct+ mat]ial4 f f are spr+s1 ! pressure ( :i* may be adju/$ by means ( ! screws g g4 ,9 ,fig4 #bde a simple arrangem5t is %[n ) two plates ( mica or o!r mat]ial4 ,x w be se5 t :5ev] "o commutator segm5t passes out ( contact ) ! bru%1 ! =mation ( ! arc w be prev5t$ by ! int]v5+ insulat+ mat]ial com+ 9 contact ) ! insulat+ mat]ial on ! bru%4 ,illu/ration3 ,,fig4 #bdd4 ,illu/ration3 ,,fig4 #bde4 ,asbe/os pap] or clo? impregnat$ ) z9c-oxide1 magnesia1 zirconia1 or o!r suitable mat]ial1 may be us$1 z ! pap] & clo? are s(t1 & s]ve at ! same "t to wipe & poli% ! commutator2 b mica or any o!r suitable mat]ial c be employ$1 provid$ ! mat]ial be an insulator or a bad conductor ( electricity4 ,a few ye>s lat] ,mr4 ,tesla turn$ 8 att5tion aga9 to ! same subject1 z1 p]haps1 0 v natural 9 view ( ! fact t ! commutator _h always be5 prom95t 9 8 ?\ghts1 & t s mu* ( 8 "w 0 ev5 aim$ at disp5s+ ) x entirely z an objectionable & unnecess>y "p ( dynamos & motors4 ,9 ^! lat] ef=ts to rem$y commutator tr\bles1 ,mr4 ,tesla con/ructs a commutator & ! collectors !re= 9 two p>ts mutually adapt$ to "o ano!r1 &1 s f> z ! ess5tial features are conc]n$1 alike 9 me*anical /ructure4 ,select+ z an illu/ration a commutator ( two segm5ts adapt$ = use ) an armature ! coils or coil ( :i* h b two free ends1 connect$ respectively to ! segm5ts1 ! be>+-surface is ! face ( a disc1 & is =m$ ( two metallic quadrant segm5ts & two insulat+ segm5ts ( ! same dim5sions1 & ! face ( ! disc is smoo!d (f1 s t ! metal & insulat+ segm5ts are flu%4 ,! "p :i* takes ! place ( ! usual bru%es1 or ! collector1 is a disc ( ! same "* z ! commutator & has a surface simil>ly =m$ ) two insulat+ & two metallic segm5ts4 ,^! two p>ts are m\nt$ ) _! faces 9 contact & 9 su* mann] t ! rotation ( ! armature causes ! commutator to turn ^u ! collector1 :]eby ! curr5ts induc$ 9 ! coils are tak5 (f by ! collector segm5ts & !nce convey$ (f by suitable conductors lead+ f ! collector segm5ts4 ,?is is ! g5]al plan ( ! con/ruction adopt$4 ,aside f c]ta9 adjuncts1 ! nature & functions ( :i* are set =? lat]1 ?is means ( commutation w be se5 to possess _m important advantages4 ,9 ! fir/ place ! %ort-circuit+ & ! break+ ( ! armature coil connect$ to ! commutator-segm5ts occur at ! same in/ant1 & f ! nature ( ! con/ruction ?is w be done ) ! greate/ precision2 secondly1 ! duration ( bo? ! break & ( ! %ort circuit w be r$uc$ to a m9imum4 ,! fir/ results 9 a r$uction :i* am\nts practically to a suppression ( ! sp>k1 s9ce ! break & ! %ort circuit produce opposite effects 9 ! armature-coil4 ,! second has ! effect ( dim9i%+ ! de/ructive effect ( a sp>k1 s9ce ?is w\ld be 9 a measure proportional to ! duration ( ! sp>k2 :ile less5+ ! duration ( ! %ort circuit obvi\sly increases ! effici5cy ( ! ma*9e4 ,illu/ration3 ,,fig4 #bdf4 ,illu/ration3 ,,fig4 #bdg4 ,! me*anical advantages w be bett] und]/ood by ref]r+ to ! accompany+ diagrams1 9 :i* ,fig4 #bdf is a c5tral longitud9al section ( ! end ( a %aft ) ! improv$ commutator c>ri$ !reon4 ,fig4 #bdg is a view ( ! inn] or be>+ face ( ! collector4 ,fig4 #bdh is an end view f ! armature side ( a modifi$ =m ( commutator4 ,figs4 #bdi & #bej are views ( details ( ,fig4 #bdh4 ,fig4 #bea is a longitud9al c5tral section ( ano!r modification1 & ,fig4 #beb is a sectional view ( ! same4 ,a is ! end ( ! armature-%aft ( a dynamo-electric ma*9e or motor4 ,a' is a sleeve ( insulat+ mat]ial ar\nd ! %aft1 secur$ 9 place by a screw1 a'4 ,illu/ration3 ,,fig4 #bdh4 ,illu/ration3 ,,fig4 #bdi4 ,illu/ration3 ,,fig4 #bej4 ,! commutator prop] is 9 ! =m ( a disc :i* is made up ( f\r segm5ts ,d ,d' ,g ,g'1 simil> to ^? %[n 9 ,fig4 #bdh4 ,two ( ^! segm5ts1 z ,d ,d'1 are ( metal & are 9 electrical connection ) ! ends ( ! coils on ! armature4 ,! o!r two segm5ts are ( insulat+ mat]ial4 ,! segm5ts are held 9 place by a b&1 ,b1 ( insulat+ mat]ial4 ,! disc is held 9 place by friction or by screws1 g' g'1 ,fig4 #bdh1 :i* secure ! disc firmly to ! sleeve ,a'4 ,! collector is made 9 ! same =m z ! commutator4 ,x is compos$ ( ! two metallic segm5ts ,e ,e' & ! two insulat+ segm5ts ,f ,f'1 b\nd toge!r by a b&1 ,c4 ,! metallic segm5ts ,e ,e' are ( ! same or practically ! same wid? or ext5t z ! insulat+ segm5ts or spaces ( ! commutator4 ,! collector is secur$ to a sleeve1 ,b'1 by screws g g1 & ! sleeve is arrang$ to turn freely on ! %aft ,a4 ,! end ( ! sleeve ,b' is clos$ by a plate1 f1 ^u :i* presses a pivot-po9t$ screw1 h1 adju/able 9 a spr+1 ,h1 :i* acts to ma9ta9 ! collector 9 close contact ) ! commutator & to comp5sate = ! play ( ! %aft4 ,! collector is s fix$ t x _c turn ) ! %aft4 ,= example1 ! diagram %[s a slott$ plate1 ,k1 :i* is design$ to be atta*$ to a /ation>y support1 & an arm ext5d+ f ! collector & c>ry+ a clamp+ screw1 ,l1 by :i* ! collector may be adju/$ & set to ! desir$ position4 ,mr4 ,tesla pref]s ! =m %[n 9 ,figs4 #bdf & #bdg to fit ! insulat+ segm5ts ( bo? commutator & collector loosely & to provide "s means--z1 = example1 light spr+s1 e e1 secur$ to ! b&s ,a' ,b'1 respectively1 & be>+ aga9/ ! segm5ts--to ex]t a light pressure ^u !m & keep !m 9 close contact & to comp5sate = we>4 ,! metal segm5ts ( ! commutator may be mov$ =w>d by loos5+ ! screw a'4 ,! l9e wires are f$ f ! metal segm5ts ( ! collector1 be+ secur$ !reto 9 any conv5i5t mann]1 ! plan ( connections be+ %[n z appli$ to a modifi$ =m ( ! commutator 9 ,fig4 #bea4 ,! commutator & ! collector 9 ?us pres5t+ two flat & smoo? be>+ surfaces prev5t mo/ effectually by me*anical action ! occurr5ce ( sp>ks4 ,! insulat+ segm5ts are made ( "s h>d mat]ial capable ( be+ poli%$ & =m$ ) %>p edges4 ,su* mat]ials z glass1 m>ble1 or soap/one may be advantage\sly us$4 ,! metal segm5ts are pref]ably ( copp] or brass2 b !y may h a fac+ or edge ( durable mat]ial--su* z plat9um or ! l--:]e ! sp>ks are liable to occur4 ,illu/ration3 ,,fig4 #bea4 ,illu/ration3 ,,fig4 #beb4 ,9 ,fig4 #bdh a some:at modifi$ =m ( ! inv5tion is %[n1 a =m design$ to facilitate ! con/ruction & replac+ ( ! p>ts4 ,9 ?is modification ! commutator & collector are made 9 sub/antially ! same mann] z previ\sly describ$1 except t ! b&s ,b ,c are omitt$4 ,! f\r segm5ts ( ea* "p1 h[ev]1 are secur$ to _! respective sleeves by screws g' g'1 & "o edge ( ea* segm5t is cut away1 s t small plates a b may be slipp$ into ! spaces ?us =m$4 ,( ^! plates a a are ( metal1 & are 9 contact ) ! metal segm5ts ,d ,d'1 respectively4 ,! o!r two1 b b1 are ( glass or m>ble1 & !y are all bett] squ>e1 z %[n 9 ,figs4 #bdi & #bej1 s t !y may be turn$ to pres5t new edges %\ld any edge become worn by use4 ,light spr+s d be> ^u ^! plates & press ^? 9 ! commutator t[>d ^? 9 ! collector1 & insulat+ /rips c c are secur$ to ! p]iph]y ( ! discs to prev5t ! blocks f be+ ?r[n out by c5trifugal action4 ,^! plates are1 ( c\rse1 useful at ^? edges ( ! segm5ts only :]e sp>ks are liable to occur1 &1 z !y are easily replac$1 !y are ( great advantage4 ,x is consid]$ be/ to coat !m ) plat9um or silv]4 ,9 ,figs4 #bea & #beb is %[n a con/ruction :]e1 in/ead ( solid segm5ts1 a fluid is employ$4 ,9 ?is case ! commutator & collector are made ( two insulat+ discs1 ,s ,t1 & 9 lieu ( ! metal segm5ts a space is cut out ( ea* "p1 z at ,r ,r'1 correspond+ 9 %ape & size to a metal segm5t4 ,! two p>ts are fitt$ smoo?ly & ! collector ,t held by ! screw h & spr+ ,h aga9/ ! commutator ,s4 ,z 9 ! o!r cases1 ! commutator revolves :ile ! collector rema9s /ation>y4 ,! ends ( ! coils are connect$ to b9d+-po/s s s1 :i* are 9 electrical connection ) metal plates t t )9 ! recesses 9 ! two p>ts ,s ,t4 ,^! *amb]s or recesses are fill$ ) m]cury1 & 9 ! collector "p are tubes ,w ,w1 ) screws w w1 c>ry+ spr+s ,x & pi/ons ,x'1 :i* comp5sate = ! expansion & contraction ( ! m]cury "u v>y+ temp]atures1 b :i* are suffici5tly /rong n to yield to ! pressure ( ! fluid due to c5trifugal action1 & :i* s]ve z b9d+-po/s4 ,9 all ! above cases ! commutators are adapt$ = a s+le coil1 & ! device is p>ticul>ly suit$ to su* purposes4 ,! numb] ( segm5ts may be increas$1 h[ev]1 or m ?an "o commutator us$ ) a s+le armature4 ,al?\gh ! be>+-surfaces are %[n z planes at "r angles to ! %aft or axis1 x is evid5t t 9 ?is p>ticul> ! con/ruction may be v greatly modifi$4 ,,*apt] ,,xxxviii4 ,,auxili>y ,,bru% ,,regulation ,,( ,,direct ,,curr5t ,,dynamos4 ,an int]e/+ me?od devis$ by ,mr4 ,tesla = ! regulation ( direct curr5t dynamos1 is t :i* has come to be kn[n z ! ?ird bru% me?od4 ,9 ma*9es ( ?is type1 devis$ by him z f> back z #ahhe1 he makes use ( two ma9 bru%es to :i* ! ends ( ! field magnet coils are connect$1 an auxili>y bru%1 & a bran* or %unt connection f an int]m$iate po9t ( ! field wire to ! auxili>y bru%4#ad #ad ,! compil] has le>n$ p>tially f /atem5ts made on sev]al occasions 9 j\rnals & p>tially by p]sonal inquiry ( ,mr4 ,tesla1 t a great deal ( "w 9 ?is int]e/+ l9e is unpubli%$4 ,9 ^! inv5tions z w be se51 ! bru%es are automatically %ift$1 b 9 ! broad me?od b>ely sugge/$ "h ! regulation is effect$ )\t any *ange 9 ! position ( ! bru%es4 ,?is auxili>y bru% inv5tion1 x w be rememb]$1 0 v mu* discuss$ a few ye>s ago1 & x may be ( int]e/ t ?is "w ( ,mr4 ,tesla1 !n unkn[n 9 ?is field1 is n[ br\ght to light4 ,! relative positions ( ! respective bru%es are v>i$1 ei!r automatically or by h&1 s t ! %unt becomes inop]ative :5 ! auxili>y bru% has a c]ta9 position ^u ! commutator2 b :5 ! auxili>y bru% is mov$ 9 its relation to ! ma9 bru%es1 or ! latt] are mov$ 9 _! relation to ! auxili>y bru%1 ! electric condition is di/urb$ & m or less ( ! curr5t ?r\gh ! field-helices is div]t$ ?r\gh ! %unt or a curr5t is pass$ ov] ! %unt to ! field-helices4 ,by v>y+ ! relative position ^u ! commutator ( ! respective bru%es automatically 9 proportion to ! v>y+ electrical conditions ( ! work+-circuit1 ! curr5t develop$ c be regulat$ 9 proportion to ! dem&s 9 ! work+-circuit4 ,fig4 #bec is a diagram illu/rat+ ! inv5tion1 %[+ "o core ( ! field-magnets ) "o helix w\nd 9 ! same direction ?r\gh\t4 ,figs4 #bed & #bee are diagrams %[+ "o core ( ! field-magnets ) a portion ( ! helices w\nd 9 opposite directions4 ,figs4 #bef & #beg are diagrams illu/rat+ ! electric devices t may be employ$ = automatically adju/+ ! bru%es1 & ,fig4 #beh is a diagram illu/rat+ ! positions ( ! bru%es :5 ! ma*9e is be+ en]giz$ at ! />t4 a & b are ! positive & negative bru%es ( ! ma9 or work+-circuit1 & c ! auxili>y bru%4 ,! work+-circuit ,d ext5ds f ! bru%es a & b1 z usual1 & conta9s electric lamps or o!r devices1 ,d'1 ei!r 9 s]ies or 9 multiple arc4 ,m ,m' repres5t ! field-helices1 ! ends ( :i* are connect$ to ! ma9 bru%es a & b4 ,! bran* or %unt wire c' ext5ds f ! auxili>y bru% c to ! circuit ( ! field-helices1 & is connect$ to ! same at an int]m$iate po9t1 x4 ,illu/ration3 ,,fig4 #bec4 ,h repres5ts ! commutator1 ) ! plates ( ord9>y con/ruction4 ,:5 ! auxili>y bru% c occupies su* a position ^u ! commutator t ! electro-motive =ce betwe5 ! bru%es a & c is to ! electro-motive =ce betwe5 ! bru%es c & b z ! resi/ance ( ! circuit a ,m c' c ,a is to ! resi/ance ( ! circuit b ,m' c' c ,b1 ! pot5tials ( ! po9ts x & ,y w be equal1 & no curr5t w fl[ ov] ! auxili>y bru%2 b :5 ! bru% c occupies a diff]5t position ! pot5tials ( ! po9ts x & ,y w be diff]5t1 & a curr5t w fl[ ov] ! auxili>y bru% to & f ! commutator1 accord+ to ! relative position ( ! bru%es4 ,if1 = in/ance1 ! commutator-space betwe5 ! bru%es a & c1 :5 ! latt] is at ! neutral po9t1 is dim9i%$1 a curr5t w fl[ f ! po9t ,y ov] ! %unt c to ! bru% b1 ?us /r5g!n+ ! curr5t 9 ! "p ,m'1 & p>tly neutraliz+ ! curr5t 9 "p ,m2 b if ! space betwe5 ! bru%es a & c is increas$1 ! curr5t w fl[ ov] ! auxili>y bru% 9 an opposite direction1 & ! curr5t 9 ,m w be /r5g!n$1 & 9 ,m'1 p>tly neutraliz$4 ,by comb9+ ) ! bru%es a1 b1 & c any usual automatic regulat+ me*anism1 ! curr5t develop$ c be regulat$ 9 proportion to ! dem&s 9 ! work+ circuit4 ,! p>ts ,m & ,m' ( ! field wire may be w\nd 9 ! same direction4 ,9 ?is case !y are arrang$ z %[n 9 ,fig4 #bec2 or ! "p ,m may be w\nd 9 ! opposite direction1 z %[n 9 ,figs4 #bed & #bee4 ,illu/ration3 ,,fig4 #bed4 ,x w be app>5t t ! respective cores ( ! field-magnets are subject$ to neutraliz+ or int5sify+ effects ( ! curr5t 9 ! %unt ?r\gh c'1 & ! magnetism ( ! cores w be p>tially neutraliz$1 or ! po9ts ( greate/ magnetism %ift$1 s t x w be m or less remote f or approa*+ to ! armature1 & h5ce ! aggregate en]giz+ actions ( ! field magnets on ! armature w be correspond+ly v>i$4 ,9 ! =m indicat$ 9 ,fig4 #bec ! regulation is effect$ by %ift+ ! po9t ( greate/ magnetism1 & 9 ,figs4 #bed & #bee ! same effect is produc$ by ! action ( ! curr5t 9 ! %unt pass+ ?r\gh ! neutraliz+ helix4 ,! relative positions ( ! respective bru%es may be v>i$ by mov+ ! auxili>y bru%1 or ! bru% c may rema9 /ation>y & ! core ,p be connect$ to ! ma9-bru% hold] ,a1 s z to adju/ ! bru%es a b 9 _! relation to ! bru% c4 ,if1 h[ev]1 an adju/m5t is appli$ to all ! bru%es1 z se5 9 ,fig4 #beg1 ! sol5oid %\ld be connect$ to bo? a & c1 s z to move !m t[>d or away f ea* o!r4 ,!re are sev]al kn[n devices = giv+ motion 9 proportion to an electric curr5t4 ,9 ,figs4 #bef & #beg ! mov+ cores are %[n z conv5i5t devices = obta9+ ! requir$ ext5t ( motion ) v slight *anges 9 ! curr5t pass+ ?r\gh ! helices4 ,x is und]/ood t ! adju/m5t ( ! ma9 bru%es causes v>iations 9 ! /r5g? ( ! curr5t indep5d5tly ( ! relative position ( ^? bru%es to ! auxili>y bru%4 ,9 all cases ! adju/m5t %\ld be su* t no curr5t fl[s ov] ! auxili>y bru% :5 ! dynamo is runn+ ) its normal load4 ,9 ,figs4 #bef & #beg ,a ,a indicate ! ma9-bru% hold]1 c>ry+ ! ma9 bru%es1 & ,c ! auxili>y-bru% hold]1 c>ry+ ! auxili>y bru%4 ,^! bru%-hold]s are movable 9 arcs conc5tric ) ! c5tre ( ! commutator-%aft4 ,an iron pi/on1 ,p1 ( ! sol5oid ,s1 ,fig4 #bef1 is atta*$ to ! auxili>y-bru% hold] ,c4 ,! adju/m5t is effect$ by means ( a spr+ & screw or tight5]4 ,9 ,fig4 #beg in/ead ( a sol5oid1 an iron tube inclos+ a coil is %[n4 ,! pi/on ( ! coil is atta*$ to bo? bru%-hold]s ,a ,a & ,c4 ,:5 ! bru%es are mov$ directly by electrical devices1 z %[n 9 ,figs4 #bef & #beg1 ^! are s con/ruct$ t ! =ce ex]t$ = adju/+ is practically uni=m ?r\gh ! :ole l5g? ( motion4 ,illu/ration3 ,,fig4 #bee4 ,x is true t auxili>y bru%es h be5 us$ 9 connection ) ! helices ( ! field-wire2 b 9 ^! in/ances ! helices receive ! entire curr5t ?r\gh ! auxili>y bru% or bru%es1 & ^! bru%es c\ld n be tak5 (f )\t break+ ! circuit ?r\gh ! field4 ,^! bru%es cause1 moreov]1 heavy sp>k+ at ! commutator4 ,9 ! pres5t case ! auxili>y bru% causes v little or no sp>k+1 & c be tak5 (f )\t break+ ! circuit ?r\gh ! field-helices4 ,! arrangem5t has1 besides1 ! advantage ( facilitat+ ! self-excitation ( ! ma*9e 9 all cases :]e ! resi/ance ( ! field-wire is v great comp>atively to ! resi/ance ( ! ma9 circuit at ! />t--= in/ance1 on arc-light ma*9es4 ,9 ?is case ! auxili>y bru% c is plac$ ne> to1 or bett] /ill 9 contact )1 ! bru% b1 z %[n 9 ,fig4 #beh4 ,9 ?is mann] ! "p ,m' is completely cut out1 & z ! "p ,m has a consid]ably small] resi/ance ?an ! :ole l5g? ( ! field-wire ! ma*9e excites itself1 :]eupon ! auxili>y bru% is %ift$ automatically to its normal position4 ,illu/ration3 ,,fig4 #bef4 ,illu/ration3 ,,fig4 #beg4 ,9 a fur!r me?od devis$ by ,mr4 ,tesla1 "o or m auxili>y bru%es are employ$1 by means ( :i* a portion or ! :ole ( ! field coils is %unt$4 ,accord+ to ! relative position ^u ! commutator ( ! respective bru%es m or less curr5t is caus$ to pass ?r\gh ! helices ( ! field1 & ! curr5t develop$ by ! ma*9e c be v>i$ at w by v>y+ ! relative positions ( ! bru%es4 ,illu/ration3 ,,fig4 #beh4 ,9 ,fig4 #bei1 a & b are ! positive & negative bru%es ( ! ma9 circuit1 & c an auxili>y bru%4 ,! ma9 circuit ,d ext5ds f ! bru%es a & b1 z usual1 & conta9s ! helices ,m ( ! field wire & ! electric lamps or o!r work+ devices4 ,! auxili>y bru% c is connect$ to ! po9t x ( ! ma9 circuit by means ( ! wire c'4 ,h is a commutator ( ord9>y con/ruction4 ,x w h be5 se5 f :at 0 said already t :5 ! electro-motive =ce betwe5 ! bru%es a & c is to ! electromotive =ce betwe5 ! bru%es c & b z ! resi/ance ( ! circuit a ,m c' c ,a is to ! resi/ance ( ! circuit b ,c ,b c c' ,d1 ! pot5tials ( ! po9ts x & y w be equal1 & no curr5t w pass ov] ! auxili>y bru% c2 b if t bru% occupies a diff]5t position relatively to ! ma9 bru%es ! electric condition is di/urb$1 & curr5t w fl[ ei!r f y to x or f x to y1 accord+ to ! relative position ( ! bru%es4 ,9 ! fir/ case ! curr5t ?r\gh ! field-helices w be p>tly neutraliz$ & ! magnetism ( ! field magnets w be dim9i%$4 ,9 ! second case ! curr5t w be increas$ & ! magnets ga9 /r5g?4 ,by comb9+ ) ! bru%es at a b c any automatic regulat+ me*anism1 ! curr5t develop$ c be regulat$ automatically 9 proportion to ! dem&s ( ! work+ circuit4 ,9 ,figs4 #bfd & #bfe "s ( ! automatic means are repres5t$ t maybe us$ = mov+ ! bru%es4 ,! core ,p1 ,fig4 #bfd1 ( ! sol5oid-helix ,s is connect$ ) ! bru% a to move ! same1 & 9 ,fig4 #bfe ! core ,p is %[n z )9 ! helix ,s1 & connect$ ) bru%es a & c1 s z to move ! same t[>d or f ea* o!r1 accord+ to ! /r5g? ( ! curr5t 9 ! helix1 ! helix be+ )9 an iron tube1 ,s'1 t becomes magnetiz$ & increases ! action ( ! sol5oid4 ,9 practice x is suffici5t to move only ! auxili>y bru%1 z %[n 9 ,fig4 #bfd1 z ! regulation is v s5sitive to ! slighte/ *anges2 b ! relative position ( ! auxili>y bru% to ! ma9 bru%es may be v>i$ by mov+ ! ma9 bru%es1 or bo? ma9 & auxili>y bru%es may be mov$1 z illu/rat$ 9 ,fig4 #bfe4 ,9 ! latt] two cases1 x w be und]/ood1 ! motion ( ! ma9 bru%es relatively to ! neutral l9e ( ! ma*9e causes v>iations 9 ! /r5g? ( ! curr5t indep5d5tly ( _! relative position to ! auxili>y bru%4 ,9 all cases ! adju/m5t may be su* t :5 ! ma*9e is runn+ ) ! ord9>y load1 no curr5t fl[s ov] ! auxili>y bru%4 ,! field helices may be connect$1 z %[n 9 ,fig4 #bei1 or a "p ( ! field helices may be 9 ! outgo+ & ! o!r "p 9 ! return circuit1 & two auxili>y bru%es may be employ$ z %[n 9 ,figs4 #bfa & #bfb4 ,in/ead ( %unt+ ! :ole ( ! field helices1 a portion only ( su* helices may be %unt$1 z %[n 9 ,figs4 #bfj & #bfb4 ,! arrangem5t %[n 9 ,fig4 #bfb is advantage\s1 z x dim9i%es ! sp>k+ ^u ! commutator1 ! ma9 circuit be+ clos$ ?r\gh ! auxili>y bru%es at ! mom5t ( ! break ( ! circuit at ! ma9 bru%es4 ,illu/ration3 ,,fig4 #bei4 ,illu/ration3 ,,fig4 #bfj4 ,illu/ration3 ,,fig4 #bfa4 ,illu/ration3 ,,fig4 #bfb4 ,illu/ration3 ,,fig4 #bfc4 ,! field helices may be w\nd 9 ! same direction1 or a "p may be w\nd 9 opposite directions4 ,! connection betwe5 ! helices & ! auxili>y bru% or bru%es may be made by a wire ( small resi/ance1 or a resi/ance may be int]pos$ 7,r1 ,fig4 #bfc17 betwe5 ! po9t x & ! auxili>y bru% or bru%es to divide ! s5sitiv5ess :5 ! bru%es are adju/$4 ,illu/ration3 ,,fig4 #bfd4 ,illu/ration3 ,,fig4 #bfe4 ,! accompany+ sket*es also illu/rate improvem5ts made by ,mr4 ,tesla 9 ! me*anical devices us$ to effect ! %ift+ ( ! bru%es1 9 ! use ( an auxili>y bru%4 ,fig4 #bff is an elevation ( ! regulator ) ! frame p>tly 9 section2 & ,fig4 #bfg is a section at ! l9e x x1 ,fig4 #bff4 ,c is ! commutator2 ,b & ,b'1 ! bru%-hold]s1 ,b c>ry+ ! ma9 bru%es a a'1 & ,b' ! auxili>y or %unt bru%es b b4 ,! axis ( ! bru%-hold] ,b is support$ by two pivot-screws1 p p4 ,! o!r bru%-hold]1 ,b'1 has a sleeve1 d1 & is movable ar\nd ! axis ( ! bru%-hold] ,b4 ,9 ?is way bo? bru%-hold]s c turn v freely1 ! friction ( ! p>ts be+ r$uc$ to a m9imum4 ,ov] ! bru%-hold]s is m\nt$ ! sol5oid ,s1 :i* re/s ^u a =k$ column1 c4 ,?is column also af=ds a support = ! pivots p p1 & is fa/5$ ^u a solid bracket or projection1 ,p1 :i* ext5ds f ! base ( ! ma*9e1 & is ca/ 9 "o piece ) ! same4 ,! bru%-hold]s ,b ,b' are connect$ by means ( ! l9ks e e & ! cross-piece ,f to ! iron core ,i1 :i* slides freely 9 ! tube ,t ( ! sol5oid4 ,! iron core ,i has a screw1 s1 by means ( :i* x c be rais$ & adju/$ 9 its position relatively to ! sol5oid1 s t ! pull ex]t$ ^u x by ! sol5oid is practically uni=m ?r\gh ! :ole l5g? ( motion :i* is requir$ to effect ! regulation4 ,9 ord] to effect ! adju/m5t ) great] precision1 ! core ,i is provid$ ) a small iron screw1 s'4 ,! core be+ fir/ br\ght v ne>ly 9 ! requir$ position relatively to ! sol5oid by means ( ! screw s1 ! small screw s' is !n adju/$ until ! magnetic attraction ^u ! core is ! same :5 ! core is 9 any position4 ,a conv5i5t /op1 t1 s]ves to limit ! upw>d movem5t ( ! iron core4 ,to *eck some:at ! movem5t ( ! core ,i1 a da%-pot1 ,k1 is us$4 ,! pi/on ,l ( ! da%-pot is provid$ ) a valve1 ,v1 :i* op5s by a d[nw>d pressure & all[s an easy d[nw>d movem5t ( ! iron core ,i1 b closes & *ecks ! movem5t ( ! core :5 x is pull$ up by ! action ( ! sol5oid4 ,to balance ! oppos+ =ces1 ! weight ( ! mov+ p>ts1 & ! pull ex]t$ by ! sol5oid ^u ! iron core1 ! weights ,w ,w may be us$4 ,! adju/m5t is su* t :5 ! sol5oid is trav]s$ by ! normal curr5t x is j /rong en\gh to balance ! d[nw>d pull ( ! p>ts4 ,illu/ration3 ,,fig4 #bff4 ,illu/ration3 ,,fig4 #bfg4 ,! electrical circuit-connections are sub/antially ! same z indicat$ 9 ! previ\s diagrams1 ! sol5oid be+ 9 s]ies ) ! circuit :5 ! translat+ devices are 9 s]ies1 & 9 %unt :5 ! devices are 9 multiple arc4 ,! op]ation ( ! device is z foll[s3 ,:5 ^u a decrease ( ! resi/ance ( ! circuit or = "s o!r reason1 ! curr5t is increas$1 ! sol5oid ,s ga9s 9 /r5g? & pulls up ! iron core ,i1 ?us %ift+ ! ma9 bru%es 9 ! direction ( rotation & ! auxili>y bru%es 9 ! opposite way4 ,?is dim9i%es ! /r5g? ( ! curr5t until ! oppos+ =ces are balanc$ & ! sol5oid is trav]s$ by ! normal curr5t2 b if f any cause ! curr5t 9 ! circuit is dim9i%$1 !n ! weight ( ! mov+ p>ts ov]comes ! pull ( ! sol5oid1 ! iron core ,i desc5ds1 ?us %ift+ ! bru%es ! opposite way & increas+ ! curr5t to ! normal /r5g?4 ,! da%-pot connect$ to ! iron core ,i may be ( ord9>y con/ruction2 b x is bett]1 especially 9 ma*9es = arc lights1 to provide ! pi/on ( ! da%-pot ) a valve1 z indicat$ 9 ! diagrams4 ,?is valve p]mits a comp>atively easy d[nw>d movem5t ( ! iron core1 b *ecks its movem5t :5 x is drawn up by ! sol5oid4 ,su* an arrangem5t has ! advantage t a great numb] ( lights may be put on )\t dim9i%+ ! light-p[] ( ! lamps 9 ! circuit1 z ! bru%es assume at once ! prop] position4 ,:5 lights are cut out1 ! da%-pot acts to ret>d ! movem5t2 b if ! curr5t is consid]ably increas$ ! sol5oid gets abnormally /rong & ! bru%es are %ift$ in/antly4 ,! regulator be+ prop]ly adju/$1 lights or o!r devices may be put on or out ) sc>cely any p]ceptible diff]5ce4 ,x is obvi\s t in/ead ( ! da%-pot any o!r ret>d+ device may be us$4 ,,*apt] ,,xxxix4 ,,improvem5t ,,9 ,,! ,,con/ruction ,,( ,,dynamos ,,& ,,motors4 ,?is inv5tion ( ,mr4 ,tesla is an improvem5t 9 ! con/ruction ( dynamo or magneto electric ma*9es or motors1 consi/+ 9 a novel =m ( frame & field magnet :i* r5d]s ! ma*9e m solid & compact z a /ructure1 :i* requires few] p>ts1 & :i* involves less tr\ble & exp5se 9 its manufacture4 ,x is applicable to g5]ators & motors g5]ally1 n only to ^? :i* h indep5d5t circuits adapt$ = use 9 ! ,tesla alt]nat+ curr5t sy/em1 b to o!r cont9u\s or alt]nat+ curr5t ma*9es ( ! ord9>y type g5]ally us$4 ,fig4 #bfh %[s ! ma*9e 9 side elevation4 ,fig4 #bfi is a v]tical sectional view ( ! field magnets & frame & an end view ( ! armature2 & ,fig4 #bgj is a plan view ( "o ( ! p>ts ( ! frame & ! armature1 a portion ( ! latt] be+ cut away4 ,! field magnets & frame are ca/ 9 two p>ts4 ,^! p>ts are id5tical 9 size & %ape1 & ea* consi/s ( ! solid plates or ends ,a ,b1 f :i* project inw>dly ! cores ,c ,d & ! side b>s or bridge pieces1 ,e ,f4 ,! precise %ape ( ^! p>ts is l>gely a matt] ( *oice--t is to say1 ea* ca/+1 z %[n1 =ms an approximately rectangul> frame2 b x might obvi\sly be m or less oval1 r\nd1 or squ>e1 )\t dep>ture f ! inv5tion4 ,x is also desirable to r$uce ! wid? ( ! side b>s1 ,e ,f1 at ! c5t] & to s proportion ! p>ts t :5 ! frame is put toge!r ! spaces betwe5 ! pole pieces w be practically equal to ! arcs :i* ! surfaces ( ! poles occupy4 ,! be>+s ,g = ! armature %aft are ca/ 9 ! side b>s ,e ,f4 ,! field coils are ei!r w\nd on ! pole pieces or on a =m & !n slipp$ on ov] ! ends ( ! pole pieces4 ,! l[] "p or ca/+ is secur$ to ! base aft] be+ f9i%$ (f4 ,! armature ,k on its %aft is !n m\nt$ 9 ! be>+s ( ! l[] ca/+ & ! o!r "p ( ! frame plac$ 9 position1 d[el p9s ,l or any o!r means be+ us$ to secure ! two p>ts 9 prop] position4 ,illu/ration3 ,,fig4 #bfh4 ,illu/ration3 ,,fig4 #bfi4 ,illu/ration3 ,,fig4 #bgj4 ,9 ord] to secure an easi] fit1 ! side b>s ,e ,f1 & end pieces1 ,a ,b1 are s ca/ t slots ,m are =m$ :5 ! two p>ts are put toge!r4 ,?is ma*9e possesses sev]al advantages4 ,= example1 if we magnetize ! cores alt]nately1 z indicat$ by ! *>act]s ,n ,s1 x w be se5 t ! magnetic circuit betwe5 ! poles ( ea* "p ( a ca/+ is complet$ ?r\gh ! solid iron side b>s4 ,! be>+s = ! %aft are locat$ at ! neutral po9ts ( ! field1 s t ! armature core is n affect$ by ! magnetic condition ( ! field4 ,! improvem5t is n re/rict$ to ! use ( f\r pole pieces1 z x is evid5t t ea* pole piece c\ld be divid$ or m ?an f\r =m$ by ! %ape ( ! ca/+4 ,,*apt] ,,xl4 ,,tesla ,,direct ,,curr5t ,,arc ,,light+ ,,sy/em4 ,at "o "t1 soon aft] 8 arrival 9 ,am]ica1 ,mr4 ,tesla 0 greatly int]e/$ 9 ! subject ( arc light+1 :i* !n occupi$ public att5tion & readily enli/$ ! support ( capital4 ,he !re=e work$ out a sy/em :i* 0 confid$ to a company =m$ = its exploitation1 & !n proce$$ to devote 8 en]gies to ! p]fection ( ! details ( 8 m celebrat$ rot>y field motor sy/em4 ,! ,tesla arc light+ app>atus appe>$ at a "t :5 a great _m o!r lamps & ma*9es 7 9 ! m>ket1 b x comm&$ notice by its +5uity4 ,its *ief purpose 0 to less5 ! manufactur+ co/ & simplify ! processes ( op]ation4 ,we w take up ! dynamo fir/4 ,fig4 #bga is a longitud9al section1 & ,fig4 #bgb a cross section ( ! ma*9e4 ,fig4 #bgc is a top view1 & ,fig4 #bgd a side view ( ! magnetic frame4 ,fig4 #bge is an end view ( ! commutator b>s1 & ,fig4 #bgf is a section ( ! %aft & commutator b>s4 ,fig4 #bgg is a diagram illu/rat+ ! coils ( ! armature & ! connections to ! commutator plates4 ,! cores c c c c ( ! field-magnets are tap]+ 9 bo? directions1 z %[n1 = ! purposes ( conc5trat+ ! magnetism ^u ! middle ( ! pole-pieces4 ,! connect+-frame ,f ,f ( ! field-magnets is 9 ! =m indicat$ 9 ! side view1 ,fig4 #bgd1 ! l[] "p be+ provid$ ) ! spread+ curv$ ca/ legs e e1 s t ! ma*9e w re/ firmly ^u two base-b>s1 r r4 ,to ! l[] pole1 ,s1 ( ! field-magnet ,m is fa/5$1 by means ( babbitt or o!r fusible diamagnetic mat]ial1 ! base ,b1 :i* is provid$ ) be>+s b = ! armature-%aft ,h4 ,! base ,b has a projection1 ,p1 :i* supports ! bru%-hold]s & ! regulat+ devices1 :i* are ( a special "* devis$ by ,mr4 ,tesla4 ,! armature is con/ruct$ ) ! view to r$uce to a m9imum ! loss ( p[] due to ,f\cault curr5ts & to ! *ange ( pol>ity1 & also to %ort5 z mu* z possible ! l5g? ( ! inactive wire w\nd ^u ! armature core4 ,illu/ration3 ,,fig4 #bga4 ,x is well kn[n t :5 ! armature is revolv$ betwe5 ! poles ( ! field-magnets1 curr5ts are g5]at$ 9 ! iron body ( ! armature :i* develop heat1 & consequ5tly cause a wa/e ( p[]4 ,ow+ to ! mutual action ( ! l9es ( =ce1 ! magnetic prop]ties ( iron1 & ! spe$ ( ! diff]5t portions ( ! armature core1 ^! curr5ts are g5]at$ pr9cipally on & ne> ! surface ( ! armature core1 dim9i%+ 9 /r5g? gradually t[>d ! c5tre ( ! core4 ,_! quantity is "u "s conditions proportional to ! l5g? ( ! iron body 9 ! direction 9 :i* ^! curr5ts are g5]at$4 ,by subdivid+ ! iron core electrically 9 ?is direction1 ! g5]ation ( ^! curr5ts c be r$uc$ to a great ext5t4 ,= in/ance1 if ! l5g? ( ! armature-core is twelve in*es1 & by a suitable con/ruction x is subdivid$ electrically1 s t !re are 9 ! g5]at+ direction six in*es ( iron & six in*es ( int]v5+ air-spaces or insulat+ mat]ial1 ! wa/e curr5ts w be r$uc$ to fifty p] c5t4 ,z %[n 9 ! diagrams1 ! armature is con/ruct$ ( ?9 iron discs ,d ,d ,d1 ( v>i\s diamet]s1 fa/5$ ^u ! armature-%aft 9 a suitable mann] & arrang$ accord+ to _! sizes1 s t a s]ies ( iron bodies1 i i i1 is =m$1 ea* ( :i* dim9i%es 9 ?ickness f ! c5tre t[>d ! p]iph]y4 ,at bo? ends ( ! armature ! inw>dly curv$ discs d d1 ( ca/ iron1 are fa/5$ to ! armature %aft4 ,! armature core be+ con/ruct$ z %[n1 x w be easily se5 t on ^? portions ( ! armature t are ! mo/ remote f ! axis1 & :]e ! curr5ts are pr9cipally develop$1 ! l5g? ( iron 9 ! g5]at+ direction is only a small fraction ( ! total l5g? ( ! armature core1 & besides ?is ! iron body is subdivid$ 9 ! g5]at+ direction1 & !re=e ! ,f\cault curr5ts are greatly r$uc$4 ,ano!r cause ( heat+ is ! %ift+ ( ! poles ( ! armature core4 ,9 consequ5ce ( ! subdivision ( ! iron 9 ! armature & ! increas$ surface = radiation1 ! risk ( heat+ is less5$4 ,! iron discs ,d ,d ,d are insulat$ or coat$ ) "s insulat+-pa9t1 a v c>eful insulation be+ unnecess>y1 z an electrical contact betwe5 sev]al discs c only occur at places :]e ! g5]at$ curr5ts are comp>atively weak4 ,an armature core con/ruct$ 9 ! mann] describ$ may be revolv$ betwe5 ! poles ( ! field magnets )\t %[+ ! slighte/ increase ( temp]ature4 ,illu/ration3 ,,fig4 #bgb4 ,illu/ration3 ,,fig4 #bgc4 ,! end discs1 d d1 :i* are ( suffici5t ?ickness &1 = ! sake ( *eapness1 ( ca/-iron1 are curv$ inw>dly1 z indicat$ 9 ! draw+s4 ,! ext5t ( ! curve is dep5d5t on ! am\nt ( wire to be w\nd ^u ! armatures4 ,9 ?is ma*9e ! wire is w\nd ^u ! armature 9 two sup]impos$ p>ts1 & ! curve ( ! end discs1 d d1 is s calculat$ t ! fir/ "p--t is1 practically half ( ! wire--j fills up ! holl[ space to ! l9e x x2 or1 if ! wire is w\nd 9 any o!r mann]1 ! curve is su* t :5 ! :ole ( ! wire is w\nd1 ! outside mass ( wires1 w1 & ! inside mass ( wires1 w'1 are equal at ea* side ( ! plane x x4 ,9 ?is case ! passive or electrically-inactive wires are ( ! smalle/ l5g? practicable4 ,! arrangem5t has fur!r ! advantage t ! total l5g?s ( ! cross+ wires at ! two sides ( ! plane x x are practically equal4 ,illu/ration3 ,,fig4 #bgd4 ,to equalize fur!r ! armature coils at bo? sides ( ! plates t are 9 contact ) ! bru%es1 ! w9d+ & connect+ up is effect$ 9 ! foll[+ mann]3 ,! :ole wire is w\nd ^u ! armature-core 9 two sup]impos$ p>ts1 :i* are ?or\ghly insulat$ f ea* o!r4 ,ea* ( ^! two p>ts is compos$ ( ?ree sep>at$ gr\ps ( coils4 ,! fir/ gr\p ( coils ( ! fir/ "p ( wire be+ w\nd & connect$ to ! commutator-b>s 9 ! usual mann]1 ?is gr\p is insulat$ & ! second gr\p w\nd2 b ! coils ( ?is second gr\p1 in/ead ( be+ connect$ to ! next foll[+ commutator b>s1 are connect$ to ! directly opposite b>s ( ! commutator4 ,! second gr\p is !n insulat$ & ! ?ird gr\p w\nd1 ! coils ( ?is gr\p be+ connect$ to ^? b>s to :i* !y w\ld be connect$ 9 ! usual way4 ,! wires are !n ?or\ghly insulat$ & ! second "p ( wire is w\nd & connect$ 9 ! same mann]4 ,suppose1 = in/ance1 t !re are tw5ty-f\r coils--t is1 twelve 9 ea* "p--& consequ5tly tw5ty-f\r commutator plates4 ,!re w be 9 ea* "p ?ree gr\ps1 ea* conta9+ f\r coils1 & ! coils w be connect$ z foll[s3 ,gr\ps4 ,commutator ,b>s4 ,fir/ #a--e ,fir/ "p ( wire ,second #ag--ba ,?ird #i--ac ,fir/ #ac--ag ,second "p ( wire ,second #e--i ,?ird #ba--a ,9 con/ruct+ ! armature core & w9d+ & connect+ ! coils 9 ! mann] indicat$1 ! passive or electrically inactive wire is r$uc$ to a m9imum1 & ! coils at ea* side ( ! plates t are 9 contact ) ! bru%es are practically equal4 ,9 ?is way ! electrical effici5cy ( ! ma*9e is increas$4 ,illu/ration3 ,,fig4 #bge4 ,illu/ration3 ,,fig4 #bgf4 ,! commutator plates t are %[n z outside ! be>+ b ( ! armature %aft4 ,! %aft ,h is tubul> & split at ! end portion1 & ! wires are c>ri$ ?r\gh ! same 9 ! usual mann] & connect$ to ! respective commutator plates4 ,! commutator plates are ^u a cyl9d]1 u1 & insulat$1 & ?is cyl9d] is prop]ly plac$ & !n secur$ by exp&+ ! split end ( ! %aft by a tap]+ screw plug1 v4 ,illu/ration3 ,,fig4 #bgg4 ,! arc lamps inv5t$ by ,mr4 ,tesla = use on ! circuits f ! above describ$ dynamo are ^? 9 :i* ! sep>ation & fe$ ( ! c>bon electrodes or _! equival5ts is accompli%$ by means ( electro-magnets or sol5oids 9 connection ) suitable clut* me*anism1 & 7 design$ = ! purpose ( rem$y+ c]ta9 faults common to arc lamps4 ,he propos$ to prev5t ! frequ5t vibrations ( ! movable c>bon po9t & flick]+ ( ! light aris+ !refrom2 to prev5t ! fall+ into contact ( ! c>bons2 to disp5se ) ! da% pot1 clock "w1 or ge>+ & simil> devices2 to r5d] ! lamp extremely s5sitive1 & to fe$ ! c>bon almo/ imp]ceptibly1 & !reby obta9 a v /eady & uni=m light4 ,9 t class ( lamps :]e ! regulation ( ! arc is effect$ by =ces act+ 9 opposition on a free1 movable rod or lev] directly connect$ ) ! electrode1 all or "s ( ! =ces be+ dep5d5t on ! /r5g? ( ! curr5t1 any *ange 9 ! electrical condition ( ! circuit causes a vibration & a correspond+ flick] 9 ! light4 ,?is difficulty is mo/ app>5t :5 !re are only a few lamps 9 circuit4 ,to less5 ?is difficulty lamps h be5 con/ruct$ 9 :i* ! lev] or armature1 aft] ! e/abli%+ ( ! arc1 is kept 9 a fix$ position & _c vibrate dur+ ! fe$ op]ation1 ! fe$ me*anism act+ indep5d5tly2 b 9 ^! lamps1 :5 a clamp is employ$1 x frequ5tly occurs t ! c>bons come into contact & ! light is mom5t>ily ext+ui%$1 & frequ5tly p>ts ( ! circuit are injur$4 ,9 bo? ^! classes ( lamps x has be5 cu/om>y to use da% pot1 clock "w1 or equival5t ret>d+ devices2 b ^! are (t5 unreliable & objectionable1 & increase ! co/ ( con/ruction4 ,mr4 ,tesla comb9es two electro-magnets--"o ( l[ resi/ance 9 ! ma9 or lamp circuit1 & ! o!r ( comp>atively high resi/ance 9 a %unt ar\nd ! arc--a movable armature lev]1 & a special fe$ me*anism1 ! p>ts be+ arrang$ s t 9 ! normal work+ position ( ! armature lev] ! same is kept almo/ rigidly 9 "o position1 & is n affect$ ev5 by consid]able *anges 9 ! electric circuit2 b if ! c>bons fall into contact ! armature w be actuat$ by ! magnets s z to move ! lev] & />t ! arc1 & hold ! c>bons until ! arc l5g!ns & ! armature lev] returns to ! normal position4 ,aft] ?is ! c>bon rod hold] is releas$ by ! action ( ! fe$ me*anism1 s z to fe$ ! c>bon & re/ore ! arc to its normal l5g?4 ,fig4 #bgh is an elevation ( ! me*anism made use ( 9 ?is arc lamp4 ,fig4 #bgi is a plan view4 ,fig4 #bhj is an elevation ( ! balanc+ lev] & spr+2 ,fig4 #bha is a deta*$ plan view ( ! pole pieces & armatures ^u ! friction clamp1 & ,fig4 #bhb is a section ( ! clamp+ tube4 ,m is a helix ( co>se wire 9 a circuit f ! l[] c>bon hold] to ! negative b9d+ screw -4 ,n is a helix ( f9e wire 9 a %unt betwe5 ! positive b9d+ screw & ! negative b9d+ screw -4 ,! upp] c>bon hold] ,s is a p>allel rod slid+ ?r\gh ! plates ,s' ,s#b ( ! frame ( ! lamp1 & h5ce ! electric curr5t passes f ! positive b9d+ po/ ?r\gh ! plate ,s#b1 c>bon hold] ,s1 & upp] c>bon to ! l[] c>bon1 & !nce by ! hold] & a metallic connection to ! helix ,m4 ,illu/ration3 ,,fig4 #bgh4 ,illu/ration3 ,,fig4 #bgi4 ,illu/ration3 ,,fig4 #bhj4 ,illu/ration3 ,,fig4 #bha4 ,illu/ration3 ,,fig4 #bhb4 ,! c>bon hold]s are ( ! usual "*1 & to insure electric connections ! spr+s l are made use ( to grasp ! upp] c>bon hold+ rod ,s1 b to all[ ! rod to slide freely ?r\gh ! same4 ,^! spr+s l may be adju/$ 9 _! pressure by ! screw m1 & ! spr+ l maybe su/a9$ ^u any suitable support4 ,!y are %[n z connect$ ) ! upp] end ( ! core ( ! magnet ,n4 ,ar\nd ! c>bon-hold+ rod ,s1 betwe5 ! plates ,s' ,s#b1 !re is a tube1 ,r1 :i* =ms a clamp4 ,?is tube is c\nt]-bor$1 z se5 9 ! section ,fig4 #bhb1 s t x be>s ^u ! rod ,s at its upp] end & ne> ! middle1 & at ! l[] end ( ?is tubul> clamp ,r !re are armature segm5ts r ( s(t iron4 ,a frame or arm1 n1 ext5d+1 pref]ably1 f ! core ,n#b1 supports ! lev] ,a by a fulcrum-p91 o4 ,?is lev] ,a has a hole1 ?r\gh :i* ! upp] end ( ! tubul> clamp ,r passes freely1 & f ! lev] ,a is a l9k1 q1 to ! lev] t1 :i* lev] is pivot$ at y to a r+ ^u "o ( ! columns ,s#c4 ,?is lev] t has an op5+ or b[ surr\nd+ ! tubul> clamp ,r1 & !re are p9s or pivotal connections w betwe5 ! lev] t & ?is clamp ,r1 & a spr+1 r#b1 s]ves to support or susp5d ! weight ( ! p>ts & balance !m1 or ne>ly s4 ,?is spr+ is adju/able4 ,at "o end ( ! lev] ,a is a s(t-iron armature block1 a1 ov] ! core ,m' ( ! helix ,m1 & !re is a limit+ screw1 c1 pass+ ?r\gh ?is armature block a1 & at ! o!r end ( ! lev] ,a is a s(t iron armature block1 b1 ) ! end tap]+ or w$ge %ap$1 & ! same comes close to & 9 l9e ) ! lat]al projection e on ! core ,n#b4 ,! l[] ends ( ! cores ,m' ,n#b are made ) lat]ally project+ pole-pieces ,m#c ,n#c1 respectively1 & ^! pole-pieces are concave at _! out] ends1 & are at opposite sides ( ! armature segm5ts r at ! l[] end ( ! tubul> clamp ,r4 ,! op]ation ( ^! devices is z foll[s3 ,9 ! condition ( inaction1 ! upp] c>bon re/s ^u ! l[] "o1 & :5 ! electric curr5t is turn$ on x passes freely1 by ! frame & spr+ l1 ?r\gh ! rods & c>bons to ! co>se wire & helix ,m1 & to ! negative b9d+ po/ ,v & ! core ,m' !reby is en]giz$4 ,! pole piece ,m#c attracts ! armature r1 & by ! lat]al pressure causes ! clamp ,r to grasp ! rod ,s'1 & ! lev] ,a is simultane\sly mov$ f ! position %[n by dott$ l9es1 ,fig4 #bgh1 to ! normal position %[n 9 full l9es1 & 9 s do+ ! l9k q & lev] t are rais$1 lift+ ! clamp ,r & ,s1 sep>at+ ! c>bons & =m+ ! arc4 ,! magnetism ( ! pole piece e t5ds to hold ! lev] ,a level1 or ne>ly s1 ! core ,n#b be+ en]giz$ by ! curr5t 9 ! %unt :i* conta9s ! helix ,n4 ,9 ?is position ! lev] ,a is n mov$ by any ord9>y v>iation 9 ! curr5t1 because ! armature b is /rongly attract$ by ! magnetism ( e1 & ^! p>ts are close to ea* o!r1 & ! magnetism ( e acts at "r angles to ! magnetism ( ! core ,m'4 ,if1 n[1 ! arc becomes too long1 ! curr5t ?r\gh ! helix ,m is less5$1 & ! magnetism ( ! core ,n#c is increas$ by ! great] curr5t pass+ ?r\gh ! %unt1 & ?is core ,n#c1 attract+ ! segm5tal armature r1 less5s ! hold ( ! clamp ,r ^u ! rod ,s1 all[+ ! latt] to slide & less5 ! l5g? ( ! arc1 :i* in/antly re/ores ! magnetic equilibrium & causes ! clamp ,r to hold ! rod ,s4 ,if x happ5s t ! c>bons fall into contact1 !n ! magnetism ( ,n#b is less5$ s mu* t ! attraction ( ! magnet ,m w be suffici5t to move ! armature a & lev] ,a s t ! armature b passes above ! normal position1 s z to sep>ate ! c>bons in/antly2 b :5 ! c>bons burn away1 a great] am\nt ( curr5t w pass ?r\gh ! %unt until ! attraction ( ! core ,n#b w ov]come ! attraction ( ! core ,m' & br+ ! armature lev] ,a aga9 into ! normal horizontal position1 & ?is occurs be=e ! fe$ c take place4 ,! segm5tal armature pieces r are %[n z ne>ly semicircul>4 ,!y are squ>e or ( any o!r desir$ %ape1 ! ends ( ! pole pieces ,m#c1 ,n#c be+ made to correspond 9 %ape4 ,9 a modification ( ?is lamp1 ,mr4 ,tesla provid$ means = automatically )draw+ a lamp f ! circuit1 or cutt+ x out :51 f a failure ( ! fe$1 ! arc rea*$ an abnormal l5g?2 & also means = automatically re9s]t+ su* lamp 9 ! circuit :5 ! rod drops & ! c>bons come into contact4 ,fig4 #bhc is an elevation ( ! lamp ) ! case 9 section4 ,fig4 #bhd is a sectional plan at ! l9e x x4 ,fig4 #bhe is an elevation1 p>tly 9 section1 ( ! lamp at "r angles to ,fig4 #bhc4 ,fig4 #bhf is a sectional plan at ! l9e y y ( ,fig4 #bhc4 ,fig4 #bhg is a section ( ! clamp 9 ab\t full size4 ,fig4 #bhh is a deta*$ section illu/rat+ ! connection ( ! spr+ to ! lev] t c>ries ! pivots ( ! clamp1 & ,fig4 #bhi is a diagram %[+ ! circuit-connections ( ! lamp4 ,9 ,fig4 #bhc1 ,m repres5ts ! ma9 & ,n ! %unt magnet1 bo? securely fa/5$ to ! base ,a1 :i* ) its side columns1 ,s ,s1 are ca/ 9 "o piece ( brass or o!r diamagnetic mat]ial4 ,to ! magnets are sold]$ or o!rwise fa/5$ ! brass wa%]s or discs a a a a4 ,simil> wa%]s1 b b1 ( fibre or o!r insulat+ mat]ial1 s]ve to insulate ! wires f ! brass wa%]s4 ,! magnets ,m & ,n are made v flat1 s t _! wid? exce$s ?ree times _! ?ickness1 or ev5 m4 ,9 ?is way a comp>atively small numb] ( convolutions is suffici5t to produce ! requir$ magnetism1 :ile a great] surface is (f]$ = cool+ (f ! wires4 ,illu/ration3 ,,fig4 #bhf4 ,illu/ration3 ,,fig4 #bhc4 ,illu/ration3 ,,fig4 #bhe4 ,illu/ration3 ,,fig4 #bhd4 ,illu/ration3 ,,fig4 #bhg4 ,illu/ration3 ,,fig4 #bhh4 ,! upp] pole pieces1 m n1 ( ! magnets are curv$1 z indicat$ 9 ! draw+s1 ,fig4 #bhc4 ,! l[] pole pieces m' n'1 are br\ght ne> toge!r1 tap]+ t[>d ! armature g1 z %[n 9 ,figs4 #bhd & #bhf4 ,! object ( ?is tap] is to conc5trate ! greate/ am\nt ( ! develop$ magnetism ^u ! armature1 & also to all[ ! pull to be ex]t$ always ^u ! middle ( ! armature g4 ,?is armature g is a piece ( iron 9 ! %ape ( a holl[ cyl9d]1 hav+ on ea* side a segm5t cut away1 ! wid? ( :i* is equal to ! wid? ( ! pole pieces m' n'4 ,! armature is sold]$ or o!rwise fa/5$ to ! clamp r1 :i* is =m$ ( a brass tube1 provid$ ) gripp+-jaws e e1 ,fig4 #bhg4 ,^! jaws are arcs ( a circle ( ! diamet] ( ! rod ,r1 & are made ( h>d5$ ,g]man silv]4 ,! guides f f1 ?r\gh :i* ! c>bon-hold+ rod ,r slides1 are made ( ! same mat]ial4 ,?is has ! advantage ( r$uc+ greatly ! we> & corrosion ( ! p>ts com+ 9 frictional contact ) ! rod1 :i* frequ5tly causes tr\ble4 ,! jaws e e are fa/5$ to ! inside ( ! tube r1 s t "o is a little l[] ?an ! o!r4 ,! object ( ?is is to provide a great] op5+ = ! passage ( ! rod :5 ! same is releas$ by ! clamp4 ,! clamp r is support$ on be>+s w w1 ,figs4 #bhc1 #bhe & #bhg1 :i* are j 9 ! middle betwe5 ! jaws e e4 ,! be>+s w w are c>ri$ by a lev]1 t1 "o end ( :i* re/s ^u an adju/able support1 q1 ( ! side columns1 ,s1 ! o!r end be+ connect$ by means ( ! l9k e' to ! armature-lev] ,l4 ,! armature-lev] ,l is a flat piece ( iron 9 ,n %ape1 hav+ its ends curv$ s z to correspond to ! =m ( ! upp] pole-pieces ( ! magnets ,m & ,n4 ,x is hung ^u ! pivots v v1 ,fig4 #bhd1 :i* are 9 ! jaw x ( ! top plate ,b4 ,?is plate ,b1 ) ! jaw1 is ca/ 9 "o piece & screw$ to ! side columns1 ,s ,s1 t ext5d up f ! base ,a4 ,to p>tly balance ! ov]weight ( ! mov+ p>ts1 a spr+1 s'1 ,figs4 #bhd & #bhh1 is fa/5$ to ! top plate1 ,b1 & hook$ to ! lev] t4 ,! hook o is t[>d "o side ( ! lev] or b5t a little sidewise1 z se5 9 ,fig4 #bhh4 ,by ?is means a slight t5d5cy is giv5 to sw+ ! armature t[>d ! pole-piece m' ( ! ma9 magnet4 ,! b9d+-po/s ,k ,k' are screw$ to ! base ,a4 ,a manual swit*1 = %ort-circuit+ ! lamp :5 ! c>bons are r5ew$1 is also fa/5$ to ! base4 ,?is swit* is ( ord9>y "*1 & is n %[n 9 ! draw+s4 ,! rod ,r is electrically connect$ to ! lamp-frame by means ( a flexible conductor or o!rwise4 ,! lamp-case receives a removable cov]1 s#b1 to inclose ! p>ts4 ,! electrical connections are z indicat$ diagrammatically 9 ,fig4 #bhi4 ,! wire 9 ! ma9 magnet consi/s ( two p>ts1 x' & p'4 ,^! two p>ts may be 9 two sep>at$ coils or 9 "o s+le helix1 z %[n 9 ! draw+s4 ,! "p x' be+ normally 9 circuit1 is1 ) ! f9e wire ^u ! %unt-magnet1 w\nd & trav]s$ by ! curr5t 9 ! same direction1 s z to t5d to produce simil> poles1 ,n ,n or ,s ,s1 on ! correspond+ pole-pieces ( ! magnets ,m & ,n4 ,! "p p' is only 9 circuit :5 ! lamp is cut out1 & !n ! curr5t be+ 9 ! opposite direction produces 9 ! ma9 magnet1 magnetism ( ! opposite pol>ity4 ,! op]ation is z foll[s3 ,at ! />t ! c>bons are to be 9 contact1 & ! curr5t passes f ! positive b9d+-po/ ,k to ! lamp-frame1 c>bon-hold]1 upp] & l[] c>bon1 insulat$ return-wire 9 "o ( ! side rods1 & f !re ?r\gh ! "p x' ( ! wire on ! ma9 magnet to ! negative b9d+-po/4 ,^u ! passage ( ! curr5t ! ma9 magnet is en]giz$ & attracts ! clamp+-armature g1 sw++ ! clamp & gripp+ ! rod by means ( ! gripp+ jaws e e4 ,at ! same "t ! armature lev] ,l is pull$ d[n & ! c>bons are sep>at$4 ,9 pull+ d[n ! armature lev] ,l ! ma9 magnet is assi/$ by ! %unt-magnet ,n1 ! latt] be+ magnetiz$ by magnetic induction f ! magnet ,m4 ,illu/ration3 ,,fig4 #bhi4 ,x w be se5 t ! armatures ,l & g are practically ! keep]s = ! magnets ,m & ,n1 & ow+ to ?is fact bo? magnets ) ei!r "o ( ! armatures ,l & g may be consid]$ z "o horse%oe magnet1 :i* we might t]m a comp\nd magnet4 ,! :ole ( ! s(t-iron p>ts ,m1 m'1 g1 n'1 ,n & ,l =m a comp\nd magnet4 ,! c>bons be+ sep>at$1 ! f9e wire receives a portion ( ! curr5t4 ,n[1 ! magnetic induction f ! magnet ,m is su* z to produce opposite poles on ! correspond+ ends ( ! magnet ,n2 b ! curr5t trav]s+ ! helices t5ds to produce simil> poles on ! correspond+ ends ( bo? magnets1 & !re=e z soon z ! f9e wire is trav]s$ by suffici5t curr5t ! magnetism ( ! :ole comp\nd magnet is dim9i%$4 ,) reg>d to ! armature g & ! op]ation ( ! lamp1 ! pole m' may be consid]$ z ! clamp+ & ! pole n' z ! releas+ pole4 ,z ! c>bons burn away1 ! f9e wire receives m curr5t & ! magnetism dim9i%es 9 proportion4 ,?is causes ! armature lev] ,l to sw+ & ! armature g to desc5d gradually "u ! weight ( ! mov+ p>ts until ! end p1 ,fig4 #bhc1 /rikes a /op on ! top plate1 ,b4 ,! adju/m5t is su* t :5 ?is takes place ! rod ,r is yet gripp$ securely by ! jaws e e4 ,! fur!r d[nw>d movem5t ( ! armature lev] be+ prev5t$1 ! arc becomes long] z ! c>bons are consum$1 & ! comp\nd magnet is weak5$ m & m until ! clamp+ armature g releases ! hold ( ! gripp+-jaws e e ^u ! rod ,r1 & ! rod is all[$ to drop a little1 ?us %ort5+ ! arc4 ,! f9e wire n[ receiv+ less curr5t1 ! magnetism increases1 & ! rod is clamp$ aga9 & slightly rais$1 if necess>y4 ,?is clamp+ & releas+ ( ! rod cont9ues until ! c>bons are consum$4 ,9 practice ! fe$ is s s5sitive t = ! greate/ "p ( ! "t ! movem5t ( ! rod _c be detect$ )\t "s actual measurem5t4 ,dur+ ! normal op]ation ( ! lamp ! armature lev] ,l rema9s practically /ation>y1 9 ! position %[n 9 ,fig4 #bhc4 ,%\ld x happ5 t1 ow+ to an imp]fection 9 x1 ! rod & ! c>bons drop too f>1 s z to make ! arc too %ort1 or ev5 br+ ! c>bons 9 contact1 a v small am\nt ( curr5t passes ?r\gh ! f9e wire1 & ! comp\nd magnet becomes suffici5tly /rong to act z at ! />t 9 pull+ ! armature lev] ,l d[n & sep>at+ ! c>bons to a great] di/ance4 ,x occurs (t5 9 practical "w t ! rod /icks 9 ! guides4 ,9 ?is case ! are rea*es a great l5g?1 until x f9ally breaks4 ,!n ! light goes out1 & frequ5tly ! f9e wire is injur$4 ,to prev5t su* an accid5t ,mr4 ,tesla provides ?is lamp ) an automatic cut-out :i* op]ates z foll[s3 ,:51 ^u a failure ( ! fe$1 ! arc rea*es a c]ta9 pr$et]m9$ l5g?1 su* an am\nt ( curr5t is div]t$ ?r\gh ! f9e wire t ! pol>ity ( ! comp\nd magnet is rev]s$4 ,! clamp+ armature g is n[ mov$ aga9/ ! %unt magnet ,n until x /rikes ! releas+ pole n'4 ,z soon z ! contact is e/abli%$1 ! curr5t passes f ! positive b9d+ po/ ov] ! clamp r1 armature g1 insulat$ %unt magnet1 & ! helix p' ^u ! ma9 magnet ,m to ! negative b9d+ po/4 ,9 ?is case ! curr5t passes 9 ! opposite direction & *anges ! pol>ity ( ! magnet ,m1 at ! same "t ma9ta9+ by magnetic induction 9 ! core ( ! %unt magnet ! requir$ magnetism )\t rev]sal ( pol>ity1 & ! armature g rema9s aga9/ ! %unt magnet pole n'4 ,! lamp is ?us cut out z long z ! c>bons are sep>at$4 ,! cut out may be us$ 9 ?is =m )\t any fur!r improvem5t2 b ,mr4 ,tesla arranges x s t if ! rod drops & ! c>bons come 9 contact ! arc is />t$ aga94 ,= ?is purpose he proportions ! resi/ance ( "p p' & ! numb] ( ! convolutions ( ! wire ^u ! ma9 magnet s t :5 ! c>bons come 9 contact a suffici5t am\nt ( curr5t is div]t$ ?r\gh ! c>bons & ! "p x' to de/roy or neutralize ! magnetism ( ! comp\nd magnet4 ,!n ! armature g1 hav+ a slight t5d5cy to approa* to ! clamp+ pole m'1 comes out ( contact ) ! releas+ pole n'4 ,z soon z ?is happ5s1 ! curr5t ?r\gh ! "p p' is int]rupt$1 & ! :ole curr5t passes ?r\gh ! "p x4 ,! magnet ,m is n[ /rongly magnetiz$1 ! armature g is attract$1 & ! rod clamp$4 ,at ! same "t ! armature lev] ,l is pull$ d[n out ( its normal position & ! arc />t$4 ,9 ?is way ! lamp cuts itself out automatically :5 ! arc gets too long1 & re9s]ts itself automatically 9 ! circuit if ! c>bons drop toge!r4 ,,*apt] ,,xli4 ,,improvem5t ,,9 ,,unipol> ,,g5]ators4 ,ano!r int]e/+ class ( app>atus to :i* ,mr4 ,tesla has direct$ 8 att5tion1 is t ( unipol> g5]ators1 9 :i* a disc or a cyl9drical conductor is m\nt$ betwe5 magnetic poles adapt$ to produce an approximately uni=m field4 ,9 ! disc armature ma*9es ! curr5ts induc$ 9 ! rotat+ conductor fl[ f ! c5tre to ! p]iph]y1 or conv]sely1 accord+ to ! direction ( rotation or ! l9es ( =ce z det]m9$ by ! signs ( ! magnetic poles1 & ^! curr5ts are tak5 (f usually by connections or bru%es appli$ to ! disc at po9ts on its p]iph]y & ne> its c5tre4 ,9 ! case ( ! cyl9drical armature ma*9e1 ! curr5ts develop$ 9 ! cyl9d] are tak5 (f by bru%es appli$ to ! sides ( ! cyl9d] at its ends4 ,9 ord] to develop economically an electromotive =ce available = practicable purposes1 x is necess>y ei!r to rotate ! conductor at a v high rate ( spe$ or to use a disc ( l>ge diamet] or a cyl9d] ( great l5g?2 b 9 ei!r case x becomes difficult to secure & ma9ta9 a good electrical connection betwe5 ! collect+ bru%es & ! conductor1 ow+ to ! high p]iph]al spe$4 ,x has be5 propos$ to c\ple two or m discs toge!r 9 s]ies1 ) ! object ( obta9+ a high] electro-motive =ce2 b ) ! connections h]et(ore us$ & us+ o!r conditions ( spe$ & dim5sion ( disc necess>y to secur+ good practicable results1 ?is difficulty is /ill felt to be a s]i\s ob/acle to ! use ( ?is k9d ( g5]ator4 ,^! objections ,mr4 ,tesla has s\ght to avoid by con/ruct+ a ma*9e ) two fields1 ea* hav+ a rot>y conductor m\nt$ betwe5 its poles4 ,! same pr9ciple is involv$ 9 ! case ( bo? =ms ( ma*9e above describ$1 b ! description n[ giv5 is conf9$ to ! disc type1 :i* ,mr4 ,tesla is incl9$ to favor = t ma*9e4 ,! discs are =m$ ) flanges1 aft] ! mann] ( pulleys1 & are connect$ toge!r by flexible conduct+ b&s or belts4 ,! ma*9e is built 9 su* mann] t ! direction ( magnetism or ord] ( ! poles 9 "o field ( =ce is opposite to t 9 ! o!r1 s t rotation ( ! discs 9 ! same direction develops a curr5t 9 "o f c5tre to circumf]5ce & 9 ! o!r f circumf]5ce to c5tre4 ,contacts appli$ !re=e to ! %afts ^u :i* ! discs are m\nt$ =m ! t]m9als ( a circuit ! electro-motive =ce 9 :i* is ! sum ( ! electro-motive =ces ( ! two discs4 ,x w be obvi\s t if ! direction ( magnetism 9 bo? fields be ! same1 ! same result z above w be obta9$ by driv+ ! discs 9 opposite directions & cross+ ! connect+ belts4 ,9 ?is way ! difficulty ( secur+ & ma9ta9+ good contact ) ! p]iph]ies ( ! discs is avoid$ & a *eap & durable ma*9e made :i* is useful = _m purposes--su* z = an excit] = alt]nat+ curr5t g5]ators1 = a motor1 & = any o!r purpose = :i* dynamo ma*9es are us$4 ,illu/ration3 ,,fig4 #bij4 ,illu/ration3 ,,fig4 #bia4 ,fig4 #bij is a side view1 p>tly 9 section1 ( ?is ma*9e4 ,fig4 #bia is a v]tical section ( ! same at "r angles to ! %afts4 ,9 ord] to =m a frame ) two fields ( =ce1 a support1 ,a1 is ca/ ) two pole pieces ,b ,b' integral ) x4 ,to ?is are jo9$ by bolts ,e a ca/+ ,d1 ) two simil> & correspond+ pole pieces ,c ,c'4 ,! pole pieces ,b ,b' are w\nd & connect$ to produce a field ( =ce ( giv5 pol>ity1 & ! pole pieces ,c ,c' are w\nd s z to produce a field ( opposite pol>ity4 ,! driv+ %afts ,f ,g pass ?r\gh ! poles & are j\rnal$ 9 insulat+ be>+s 9 ! ca/+ ,a ,d1 z %[n4 ,h ,k are ! discs or g5]at+ conductors4 ,!y are compos$ ( copp]1 brass1 or iron & are key$ or secur$ to _! respective %afts4 ,!y are provid$ ) broad p]iph]al flanges ,j4 ,x is ( c\rse obvi\s t ! discs may be insulat$ f _! %afts1 if s desir$4 ,a flexible metallic belt ,l is pass$ ov] ! flanges ( ! two discs1 &1 if desir$1 may be us$ to drive "o ( ! discs4 ,x is bett]1 h[ev]1 to use ?is belt m]ely z a conductor1 & = ?is purpose %eet /eel1 copp]1 or o!r suitable metal is us$4 ,ea* %aft is provid$ ) a driv+ pulley ,m1 by :i* p[] is imp>t$ f a driv+ %aft4 ,n ,n are ! t]m9als4 ,= ! sake ( cle>ness !y are %[n z provid$ ) spr+s ,p1 t be> ^u ! ends ( ! %afts4 ,?is ma*9e1 if self-excit+1 w\ld h copp] b&s ar\nd its poles2 or conductors ( any k9d--su* z wires %[n 9 ! draw+s--may be us$4 99 99 99 99 99 ,x is ?\ght appropriate by ! compil] to app5d "h "s notes on unipol> dynamos1 writt5 by ,mr4 ,tesla1 on a rec5t occasion4 ,,notes ,,on ,a ,,unipol> ,,dynamo4#ae #ae ,article by ,mr4 ,tesla1 contribut$ to ,! ,electrical ,eng9e]1 ,n4 ,y41 ,sept4 #b1 #ahia4 ,x is *>act]i/ic ( fundam5tal discov]ies1 ( great a*ievem5ts ( intellect1 t !y reta9 an undim9i%$ p[] ^u ! imag9ation ( ! ?9k]4 ,! memorable exp]im5t ( ,f>aday ) a disc rotat+ betwe5 ! two poles ( a magnet1 :i* has borne su* magnific5t fruit1 has long pass$ into e-day exp]i5ce2 yet !re are c]ta9 features ab\t ?is embryo ( ! pres5t dynamos & motors :i* ev5 to-day appe> to u /rik+1 & are wor?y ( ! mo/ c>eful /udy4 ,consid]1 = in/ance1 ! case ( a disc ( iron or o!r metal revolv+ betwe5 ! two opposite poles ( a magnet1 & ! pol> surfaces completely cov]+ bo? sides ( ! disc1 & assume ! curr5t to be tak5 (f or convey$ to ! same by contacts uni=mly f all po9ts ( ! p]iph]y ( ! disc4 ,take fir/ ! case ( a motor4 ,9 all ord9>y motors ! op]ation is dep5d5t ^u "s %ift+ or *ange ( ! resultant ( ! magnetic attraction ex]t$ ^u ! armature1 ?is process be+ effect$ ei!r by "s me*anical contrivance on ! motor or by ! action ( curr5ts ( ! prop] "*4 ,we may expla9 ! op]ation ( su* a motor j z we c t ( a wat]-:eel4 ,b 9 ! above example ( ! disc surr\nd$ completely by ! pol> surfaces1 !re is no %ift+ ( ! magnetic action1 no *ange :atev]1 z f> z we "k1 & yet rotation ensues4 ,"h1 !n1 ord9>y consid]ations d n apply2 we _c ev5 give a sup]ficial explanation1 z 9 ord9>y motors1 & ! op]ation w be cle> to u only :5 we %all h recogniz$ ! v nature ( ! =ces conc]n$1 & fa?om$ ! my/]y ( ! invisible connect+ me*anism4 ,consid]$ z a dynamo ma*9e1 ! disc is an equally int]e/+ object ( /udy4 ,9 addition to its peculi>ity ( giv+ curr5ts ( "o direction )\t ! employm5t ( commutat+ devices1 su* a ma*9e diff]s f ord9>y dynamos 9 t !re is no reaction betwe5 armature & field4 ,! armature curr5t t5ds to set up a magnetization at "r angles to t ( ! field curr5t1 b s9ce ! curr5t is tak5 (f uni=mly f all po9ts ( ! p]iph]y1 & s9ce1 to be exact1 ! ext]nal circuit may also be arrang$ p]fectly symmetrical to ! field magnet1 no reaction c occur4 ,?is1 h[ev]1 is true only z long z ! magnets are weakly en]giz$1 = :5 ! magnets are m or less saturat$1 bo? magnetizations at "r angles seem+ly int]f]e ) ea* o!r4 ,= ! above reason alone x w\ld appe> t ! output ( su* a ma*9e %\ld1 = ! same weight1 be mu* great] ?an t ( any o!r ma*9e 9 :i* ! armature curr5t t5ds to demagnetize ! field4 ,! extraord9>y output ( ! ,=bes unipol> dynamo & ! exp]i5ce ( ! writ] confirm ?is view4 ,aga91 ! facility ) :i* su* a ma*9e may be made to excite itself is /rik+1 b ?is may be due--besides to ! abs5ce ( armature reaction--to ! p]fect smoo?ness ( ! curr5t & non-exi/5ce ( self-induction4 ,if ! poles d n cov] ! disc completely on bo? sides1 !n1 ( c\rse1 unless ! disc be prop]ly subdivid$1 ! ma*9e w be v ineffici5t4 ,aga91 9 ?is case !re are po9ts wor?y ( notice4 ,if ! disc be rotat$ & ! field curr5t int]rupt$1 ! curr5t ?r\gh ! armature w cont9ue to fl[ & ! field magnets w lose _! /r5g? comp>atively sl[ly4 ,! reason = ?is w at once appe> :5 we consid] ! direction ( ! curr5ts set up 9 ! disc4 ,illu/ration3 ,,fig4 #bib4 ,ref]r+ to ! diagram ,fig4 #bib1 d repres5ts ! disc ) ! slid+ contacts ,b ,b' on ! %aft & p]iph]y4 ,n & ,s repres5t ! two poles ( a magnet4 ,if ! pole ,n be above1 z indicat$ 9 ! diagram1 ! disc be+ suppos$ to be 9 ! plane ( ! pap]1 & rotat+ 9 ! direction ( ! arr[ ,d1 ! curr5t set up 9 ! disc w fl[ f ! c5tre to ! p]iph]y1 z indicat$ by ! arr[ ,a4 ,s9ce ! magnetic action is m or less conf9$ to ! space betwe5 ! poles ,n ,s1 ! o!r portions ( ! disc may be consid]$ inactive4 ,! curr5t set up w !re=e n :olly pass ?r\gh ! ext]nal circuit ,f1 b w close ?r\gh ! disc itself1 & g5]ally1 if ! disposition be 9 any way simil> to ! "o illu/rat$1 by f> ! great] portion ( ! curr5t g5]at$ w n appe> ext]nally1 z ! circuit ,f is practically %ort-circuit$ by ! inactive portions ( ! disc4 ,! direction ( ! result+ curr5ts 9 ! latt] may be assum$ to be z indicat$ by ! dott$ l9es & arr[s m & n2 & ! direction ( ! en]giz+ field curr5t be+ indicat$ by ! arr[s a b c d1 an inspection ( ! figure %[s t "o ( ! two bran*es ( ! eddy curr5t1 t is1 ,a ,b' m ,b1 w t5d to demagnetize ! field1 :ile ! o!r bran*1 t is1 ,a ,b' n ,b1 w h ! opposite effect4 ,!re=e1 ! bran* ,a ,b' m ,b1 t is1 ! "o :i* is approa*+ ! field1 w repel ! l9es ( ! same1 :ile bran* ,a ,b' n ,b1 t is1 ! "o leav+ ! field1 w ga!r ! l9es ( =ce ^u itself4 ,9 consequ5ce ( ?is !re w be a con/ant t5d5cy to r$uce ! curr5t fl[ 9 ! pa? ,a ,b' m ,b1 :ile on ! o!r h& no su* opposition w exi/ 9 pa? ,a ,b' n ,b1 & ! effect ( ! latt] bran* or pa? w be m or less prepond]at+ ov] t ( ! =m]4 ,! jo9t effect ( bo? ! assum$ bran* curr5ts might be repres5t$ by t ( "o s+le curr5t ( ! same direction z t en]giz+ ! field4 ,9 o!r words1 ! eddy curr5ts circulat+ 9 ! disc w en]gize ! field magnet4 ,?is is a result q contr>y to :at we might be l$ to suppose at fir/1 = we w\ld naturally expect t ! result+ effect ( ! armature curr5ts w\ld be su* z to oppose ! field curr5t1 z g5]ally occurs :5 a prim>y & second>y conductor are plac$ 9 inductive relations to ea* o!r4 ,b x mu/ be rememb]$ t ?is results f ! peculi> disposition 9 ?is case1 namely1 two pa?s be+ af=d$ to ! curr5t1 & ! latt] select+ t pa? :i* (f]s ! lea/ opposition to its fl[4 ,f ?is we see t ! eddy curr5ts fl[+ 9 ! disc p>tly en]gize ! field1 & = ?is reason :5 ! field curr5t is int]rupt$ ! curr5ts 9 ! disc w cont9ue to fl[1 & ! field magnet w lose its /r5g? ) comp>ative sl[ness & may ev5 reta9 a c]ta9 /r5g? z long z ! rotation ( ! disc is cont9u$4 ,! result w1 ( c\rse1 l>gely dep5d on ! resi/ance & geometrical dim5sions ( ! pa? ( ! result+ eddy curr5t & on ! spe$ ( rotation2 ^! elem5ts1 namely1 det]m9e ! ret>dation ( ?is curr5t & its position relative to ! field4 ,= a c]ta9 spe$ !re w\ld be a maximum en]giz+ action2 !n at high] spe$s1 x w\ld gradually fall (f to z]o & f9ally rev]se1 t is1 ! resultant eddy curr5t effect w\ld be to weak5 ! field4 ,! reaction w\ld be be/ demon/rat$ exp]im5tally by arrang+ ! fields ,n ,s1 ,n' ,s'1 freely movable on an axis conc5tric ) ! %aft ( ! disc4 ,if ! latt] 7 rotat$ z be=e 9 ! direction ( ! arr[ ,d1 ! field w\ld be dragg$ 9 ! same direction ) a torque1 :i*1 up to a c]ta9 po9t1 w\ld g on increas+ ) ! spe$ ( rotation1 !n fall (f1 &1 pass+ ?r\gh z]o1 f9ally become negative2 t is1 ! field w\ld beg9 to rotate 9 opposite direction to ! disc4 ,9 exp]im5ts ) alt]nate curr5t motors 9 :i* ! field 0 %ift$ by curr5ts ( diff]+ phase1 ?is int]e/+ result 0 obs]v$4 ,= v l[ spe$s ( rotation ( ! field ! motor w\ld %[ a torque ( #ijj lbs4 or m1 measur$ on a pulley #ab in*es 9 diamet]4 ,:5 ! spe$ ( rotation ( ! poles 0 increas$1 ! torque w\ld dim9i%1 w\ld f9ally g d[n to z]o1 become negative1 & !n ! armature w\ld beg9 to rotate 9 opposite direction to ! field4 ,to return to ! pr9cipal subject2 assume ! conditions to be su* t ! eddy curr5ts g5]at$ by ! rotation ( ! disc /r5g!n ! field1 & suppose ! latt] gradually remov$ :ile ! disc is kept rotat+ at an increas$ rate4 ,! curr5t1 once />t$1 may !n be suffici5t to ma9ta9 itself & ev5 increase 9 /r5g?1 & !n we h ! case ( ,sir ,william ,?omson's curr5t accumulator4 ,b f ! above consid]ations x w\ld seem t = ! success ( ! exp]im5t ! employm5t ( a disc n subdivid$#af w\ld be ess5tial1 = if !re %\ld be a radial subdivision1 ! eddy curr5ts c\ld n =m & ! self-excit+ action w\ld cease4 ,if su* a radially subdivid$ disc 7 us$ x w\ld be necess>y to connect ! spokes by a conduct+ rim or 9 any prop] mann] s z to =m a symmetrical sy/em ( clos$ circuits4 #af ,mr4 ,tesla "h ref]s to an int]e/+ article :i* appe>$ 9 ,july1 #ahfe1 9 ! ,phil4 ,magaz9e1 by ,sir ,w4 ,?omson1 9 :i* ,sir ,william1 speak+ ( 8 uni=m electric curr5t accumulator1 assumes t = self-excitation x is desirable to subdivide ! disc into an inf9ite numb] ( inf9itely ?9 spokes1 9 ord] to prev5t diffusion ( ! curr5t4 ,mr4 ,tesla %[s t diffusion is absolutely necess>y = ! excitation & t :5 ! disc is subdivid$ no excitation c occur4 ,! action ( ! eddy curr5ts may be utiliz$ to excite a ma*9e ( any con/ruction4 ,= in/ance1 9 ,figs4 #bic & #bid an arrangem5t is %[n by :i* a ma*9e ) a disc armature might be excit$4 ,"h a numb] ( magnets1 ,n ,s1 ,n ,s1 are plac$ radially on ea* side ( a metal disc ,d c>ry+ on its rim a set ( insulat$ coils1 ,c ,c4 ,! magnets =m two sep>ate fields1 an int]nal & an ext]nal "o1 ! solid disc rotat+ 9 ! field ne>e/ ! axis1 & ! coils 9 ! field fur!r f x4 ,assume ! magnets slightly en]giz$ at ! />t2 !y c\ld be /r5g!n$ by ! action ( ! eddy curr5ts 9 ! solid disc s z to af=d a /rong] field = ! p]iph]al coils4 ,al?\gh !re is no d\bt t "u prop] conditions a ma*9e might be excit$ 9 ?is or a simil> mann]1 !re be+ suffici5t exp]im5tal evid5ce to w>rant su* an ass]tion1 su* a mode ( excitation w\ld be wa/eful4 ,b a unipol> dynamo or motor1 su* z %[n 9 ,fig4 #bib1 may be excit$ 9 an effici5t mann] by simply prop]ly subdivid+ ! disc or cyl9d] 9 :i* ! curr5ts are set up1 & x is practicable to d away ) ! field coils :i* are usually employ$4 ,su* a plan is illu/rat$ 9 ,fig4 #bie4 ,! disc or cyl9d] ,d is suppos$ to be arrang$ to rotate betwe5 ! two poles ,n & ,s ( a magnet1 :i* completely cov] x on bo? sides1 ! cont\rs ( ! disc & poles be+ repres5t$ by ! circles d & d#a respectively1 ! upp] pole be+ omitt$ = ! sake ( cle>ness4 ,! cores ( ! magnet are suppos$ to be holl[1 ! %aft ,c ( ! disc pass+ ?r\gh !m4 ,if ! unm>k$ pole be bel[1 & ! disc be rotat$ screw fa%ion1 ! curr5t w be1 z be=e1 f ! c5tre to ! p]iph]y1 & may be tak5 (f by suitable slid+ contacts1 ,b ,b'1 on ! %aft & p]iph]y respectively4 ,9 ?is arrangem5t ! curr5t fl[+ ?r\gh ! disc & ext]nal circuit w h no appreciable effect on ! field magnet4 ,illu/ration3 ,,fig4 #bic4 ,illu/ration3 ,,fig4 #bid4 ,b let u n[ suppose ! disc to be subdivid$ spirally1 z indicat$ by ! full or dott$ l9es1 ,fig4 #bie4 ,! diff]5ce ( pot5tial betwe5 a po9t on ! %aft & a po9t on ! p]iph]y w rema9 un*ang$1 9 sign z well z 9 am\nt4 ,! only diff]5ce w be t ! resi/ance ( ! disc w be augm5t$ & t !re w be a great] fall ( pot5tial f a po9t on ! %aft to a po9t on ! p]iph]y :5 ! same curr5t is trav]s+ ! ext]nal circuit4 ,b s9ce ! curr5t is =c$ to foll[ ! l9es ( subdivision1 we see t x w t5d ei!r to en]gize or de-en]gize ! field1 & ?is w dep5d1 o!r ?+s be+ equal1 ^u ! direction ( ! l9es ( subdivision4 ,if ! subdivision be z indicat$ by ! full l9es 9 ,fig4 #bie1 x is evid5t t if ! curr5t is ( ! same direction z be=e1 t is1 f c5tre to p]iph]y1 its effect w be to /r5g!n ! field magnet2 ,:]eas1 if ! subdivision be z indicat$ by ! dott$ l9es1 ! curr5t g5]at$ w t5d to weak5 ! magnet4 ,9 ! =m] case ! ma*9e w be capable ( excit+ itself :5 ! disc is rotat$ 9 ! direction ( arr[ ,d2 9 ! latt] case ! direction ( rotation mu/ be rev]s$4 ,two su* discs may be comb9$1 h[ev]1 z indicat$1 ! two discs rotat+ 9 opposite fields1 & 9 ! same or opposite direction4 ,illu/ration3 ,,fig4 #bie4 ,illu/ration3 ,,fig4 #bif4 ,simil> disposition may1 ( c\rse1 be made 9 a type ( ma*9e 9 :i*1 in/ead ( a disc1 a cyl9d] is rotat$4 ,9 su* unipol> ma*9es1 9 ! mann] indicat$1 ! usual field coils & poles may be omitt$ & ! ma*9e may be made to consi/ only ( a cyl9d] or ( two discs envelop$ by a metal ca/+4 ,in/ead ( subdivid+ ! disc or cyl9d] spirally1 z indicat$ 9 ,fig4 #bie1 x is m conv5i5t to int]pose "o or m turns betwe5 ! disc & ! contact r+ on ! p]iph]y1 z illu/rat$ 9 ,fig4 #bif4 ,a ,=bes dynamo may1 = in/ance1 be excit$ 9 su* a mann]4 ,9 ! exp]i5ce ( ! writ] x has be5 f\nd t in/ead ( tak+ ! curr5t f two su* discs by slid+ contacts1 z usual1 a flexible conduct+ belt may be employ$ to advantage4 ,! discs are 9 su* case provid$ ) l>ge flanges1 af=d+ a v great contact surface4 ,! belt %\ld be made to be> on ! flanges ) spr+ pressure to take up ! expansion4 ,sev]al ma*9es ) belt contact 7 con/ruct$ by ! writ] two ye>s ago1 & work$ satisfactorily2 b = want ( "t ! "w 9 t direction has be5 tempor>ily susp5d$4 ,a numb] ( features po9t$ out above h also be5 us$ by ! writ] 9 connection ) "s types ( alt]nat+ curr5t motors4 ,,"p ,,iv4 ,,app5dix4--,,e>ly ,,phase ,,motors ,,& ,,! ,,tesla ,,me*anical ,,& ,,electrical ,,oscillator4 ,,*apt] ,,xlii4 ,,mr4 ,,tesla',s ,,p]sonal ,,exhibit ,,at ,,! ,,_w',s ,,fair4 ,:ile ! exhibits ( firms engag$ 9 ! manufacture ( electrical app>atus ( e description at ! ,*icago ,_w's ,fair1 af=d$ ! visitor ample opportunity = ga9+ an excell5t k ( ! /ate ( ! art1 !re 7 also numb]s ( exhibits :i* br\ght out 9 /rong relief ! "w ( ! individual inv5tor1 :i* lies at ! f\ndation ( mu*1 if n all1 indu/rial or me*anical a*ievem5t4 ,prom95t among su* p]sonal exhibits 0 t ( ,mr4 ,tesla1 ^: app>atus occupi$ "p ( ! space ( ! ,we/+h\se ,company1 9 ,electricity ,build+4 ,?is app>atus repres5t$ ! results ( "w & ?\ght cov]+ a p]iod ( t5 ye>s4 ,x embrac$ a l>ge numb] ( diff]5t alt]nat+ motors & ,mr4 ,tesla's e>li] high frequ5cy app>atus4 ,! motor exhibit consi/$ ( a v>iety ( fields & armatures = two1 ?ree & multiphase circuits1 & gave a fair idea ( ! gradual evolution ( ! fundam5tal idea ( ! rotat+ magnetic field4 ,! high frequ5cy exhibit includ$ ,mr4 ,tesla's e>li] ma*9es & disruptive dis*>ge coils & high frequ5cy trans=m]s1 :i* he us$ 9 8 inve/igations & "s ( :i* are ref]r$ to 9 8 pap]s pr9t$ 9 ?is volume4 ,fig4 #big %[s a view ( "p ( ! exhibits conta9+ ! motor app>atus4 ,among ^! is %[n at ,a a l>ge r+ int5d$ to exhibit ! ph5om5a ( ! rotat+ magnetic field4 ,! field produc$ 0 v p[]ful & exhibit$ /rik+ effects1 revolv+ copp] balls & eggs & bodies ( v>i\s %apes at consid]able di/ances & at great spe$s4 ,?is r+ 0 w\nd = two-phase circuits1 & ! w9d+ 0 s di/ribut$ t a practically uni=m field 0 obta9$4 ,?is r+ 0 prep>$ = ,mr4 ,tesla's exhibit by ,mr4 ,c4 ,f4 ,scott1 electrician ( ! ,we/+h\se ,electric & ,manufactur+ ,company4 ,illu/ration3 ,,fig4 #big4 ,a small] r+1 %[n at ,b1 0 arrang$ l ! "o exhibit$ at ,a b design$ especially to exhibit ! rotation ( an armature 9 a rotat+ field4 ,9 connection ) ^! two r+s !re 0 an int]e/+ exhibit %[n by ,mr4 ,tesla :i* consi/$ ( a magnet ) a coil1 ! magnet be+ arrang$ to rotate 9 be>+s4 ,) ?is magnet he fir/ demon/rat$ ! id5tity betwe5 a rotat+ field & a rotat+ magnet2 ! latt]1 :5 rotat+1 exhibit$ ! same ph5om5a z ! r+s :5 !y 7 en]giz$ by curr5ts ( diff]+ phase4 ,ano!r prom95t exhibit 0 a model illu/rat$ at ,c :i* is a two-phase motor1 z well z an induction motor & trans=m]4 ,x consi/s ( a l>ge out] r+ ( lam9at$ iron w\nd ) two sup]impos$1 sep>at$ w9d+s :i* c be connect$ 9 a v>iety ( ways4 ,?is is "o ( ! fir/ models us$ by ,mr4 ,tesla z an induction motor & rotat+ trans=m]4 ,! armature 0 ei!r a /eel or wr\ght iron disc ) a clos$ coil4 ,:5 ! motor 0 op]at$ f a two phase g5]ator ! w9d+s 7 connect$ 9 two gr\ps1 z usual4 ,:5 us$ z an induction motor1 ! curr5t induc$ 9 "o ( ! w9d+s ( ! r+ 0 pass$ ?r\gh ! o!r w9d+ on ! r+ & s ! motor op]at$ ) only two wires4 ,:5 us$ z a trans=m] ! out] w9d+ s]v$1 = in/ance1 z a second>y & ! inn] z a prim>y4 ,! model %[n at ,d is "o ( ! e>lie/ rotat+ field motors1 consi/+ ( a ?9 iron r+ w\nd ) two sets ( coils & an armature consi/+ ( a s]ies ( /eel discs p>tly cut away & arrang$ on a small arbor4 ,at ,e is %[n "o ( ! fir/ rotat+ field or induction motors us$ = ! regulation ( an arc lamp & = o!r purposes4 ,x comprises a r+ ( discs ) two sets ( coils hav+ diff]5t self-inductions1 "o set be+ ( ,g]man silv] & ! o!r ( copp] wire4 ,! armature is w\nd ) two clos$-circuit$ coils at "r angles to ea* o!r4 ,to ! armature %aft are fa/5$ lev]s & o!r devices to effect ! regulation4 ,at ,f is %[n a model ( a magnetic lag motor2 ?is embodies a ca/+ ) pole projections protrud+ f two coils betwe5 :i* is arrang$ to rotate a smoo? iron body4 ,:5 an alt]nat+ curr5t is s5t ?r\gh ! two coils ! pole projections ( ! field & armature )9 x are simil>ly magnetiz$1 & ^u ! cessation or rev]sal ( ! curr5t ! armature & field repel ea* o!r & rotation is produc$ 9 ?is way4 ,ano!r int]e/+ exhibit1 %[n at ,g1 is an e>ly model ( a two field motor en]giz$ by curr5ts ( diff]5t phase4 ,!re are two indep5d5t fields ( lam9at$ iron jo9$ by brass bolts2 9 ea* field is m\nt$ an armature1 bo? armatures be+ on ! same %aft4 ,! armatures 7 orig9ally s arrang$ z to be plac$ 9 any position relatively to ea* o!r1 & ! fields also 7 arrang$ to be connect$ 9 a numb] ( ways4 ,! motor has s]v$ = ! exhibition ( a numb] ( features2 among o!r ?+s1 x has be5 us$ z a dynamo = ! production ( curr5ts ( any frequ5cy betwe5 wide limits4 ,9 ?is case ! field1 in/ead ( be+ en]giz$ by direct curr5t1 0 en]giz$ by curr5ts diff]+ 9 phase1 :i* produc$ a rotation ( ! field2 ! armature 0 !n rotat$ 9 ! same or 9 opposite direction to ! movem5t ( ! field2 & s any numb] ( alt]nations ( ! curr5ts induc$ 9 ! armature1 f a small to a high numb]1 det]m9$ by ! frequ5cy ( ! en]giz+ field coils & ! spe$ ( ! armature1 0 obta9$4 ,illu/ration3 ,,fig4 #bih4 ,! models ,h1 ,i1 ,j1 repres5t a v>iety ( rotat+ field1 syn*ron\s motors :i* are ( special value 9 long di/ance transmission "w4 ,! pr9ciple embodi$ 9 ^! motors 0 enunciat$ by ,mr4 ,tesla 9 8 lecture be=e ! ,am]ican ,in/itute ( ,electrical ,eng9e]s1 9 ,may1 #ahhhag4 ,x involves ! production ( ! rotat+ field 9 "o ( ! elem5ts ( ! motor by curr5ts diff]+ 9 phase & en]giz+ ! o!r elem5t by direct curr5ts4 ,! armatures are ( ! two & ?ree phase type4 ,k is a model ( a motor %[n 9 an enl>g$ view 9 ,fig4 #bih4 ,?is ma*9e1 toge!r ) t %[n 9 ,fig4 #bii1 0 exhibit$ at ! same lecture1 9 ,may1 #ahhh4 ,!y 7 ! fir/ rotat+ field motors :i* 7 indep5d5tly te/$1 hav+ = t purpose be5 plac$ 9 ! h&s ( ,pr(4 ,an?ony 9 ! w9t] ( #ahhg-hh4 ,f ^! te/s x 0 %[n t ! effici5cy & output ( ^! motors 0 q satisfactory 9 e respect4 #ag ,see ,"p ,i1 ,*ap4 ,,iii1 page #i4 ,illu/ration3 ,,fig4 #bii4 ,x 0 int5d$ to exhibit ! model %[n 9 ,fig4 #bii1 b x 0 unavailable = t purpose ow+ to ! fact t x 0 "s "t ago h&$ ov] to ! c>e ( ,pr(4 ,ayrton 9 ,engl&4 ,?is model 0 orig9ally provid$ ) twelve indep5d5t coils2 ?is numb]1 z ,mr4 ,tesla po9t$ out 9 8 fir/ lecture1 be+ divisible by two & ?ree1 0 select$ 9 ord] to make v>i\s connections = two & ?ree-phase op]ations1 & dur+ ,mr4 ,tesla's exp]im5ts 0 us$ 9 _m ways ) f two to six phases4 ,! model1 ,fig4 #bih1 consi/s ( a magnetic frame ( lam9at$ iron ) f\r pol> projections betwe5 :i* an armature is support$ on brass bolts pass+ ?r\gh ! frame4 ,a great v>iety ( armatures 0 us$ 9 connection ) ^! two & o!r fields4 ,"s ( ! armatures are %[n 9 front on ! table1 ,fig4 #big1 & sev]al are also %[n enl>g$ 9 ,figs4 #cjj to #caj4 ,an int]e/+ exhibit is t %[n at ,l1 ,fig4 #big4 ,?is is an armature ( h>d5$ /eel :i* 0 us$ 9 a demon/ration be=e ! ,society ( ,arts 9 ,bo/on1 by ,pr(4 ,an?ony4 ,ano!r curi\s exhibit is %[n enl>g$ 9 ,fig4 #cja4 ,?is consi/s ( ?ick discs ( wr\ght iron plac$ l5g?wise1 ) a mass ( copp] ca/ ar\nd !m4 ,! discs 7 arrang$ longitud9ally to af=d an easi] />t+ by reason ( ! induc$ curr5t =m$ 9 ! iron discs1 :i* diff]$ 9 phase f ^? 9 ! copp]4 ,?is armature w\ld />t ) a s+le circuit & run 9 syn*ronism1 & repres5ts "o ( ! e>lie/ types ( su* an armature4 ,fig4 #cje is ano!r /rik+ exhibit4 ,?is is "o ( ! e>lie/ types ( an armature ) holes b5ea? ! p]iph]y1 9 :i* copp] conductors are imb$d$4 ,! armature has eight clos$ circuits & 0 us$ 9 _m diff]5t ways4 ,fig4 #cjd is a type ( syn*ron\s armature consi/+ ( a block ( s(t /eel w\nd ) a coil clos$ ^u itself4 ,?is armature 0 us$ 9 connection ) ! field %[n 9 ,fig4 #bih & gave excell5t results4 ,illu/ration3 ,,fig4 #cjj4 ,illu/ration3 ,,fig4 #cja4 ,illu/ration3 ,,fig4 #cjb4 ,illu/ration3 ,,fig4 #cjc4 ,illu/ration3 ,,fig4 #cjd4 ,illu/ration3 ,,fig4 #cje4 ,illu/ration3 ,,fig4 #cjf4 ,illu/ration3 ,,fig4 #cjg4 ,illu/ration3 ,,fig4 #cjh4 ,illu/ration3 ,,fig4 #cji4 ,illu/ration3 ,,fig4 #caj4 ,fig4 #cjb repres5ts a syn*ron\s armature ) a l>ge coil ar\nd a body ( iron4 ,!re is ano!r v small coil at "r angles to ! fir/4 ,?is small coil 0 us$ = ! purpose ( increas+ ! />t+ torque & 0 f\nd v effective 9 ?is connection4 ,figs4 #cjf & #cjh %[ a favorite con/ruction ( armature2 ! iron body is made up ( two sets ( discs cut away & plac$ at "r angles to ea* o!r1 ! int]/ices be+ w\nd ) coils4 ,! "o %[n 9 ,fig4 #cjh is provid$ ) an additional groove on ea* ( ! projections =m$ by ! discs1 = ! purpose ( increas+ ! />t+ torque by a wire w\nd 9 ^! projections4 ,fig4 #cjg is a =m ( armature simil>ly con/ruct$1 b ) f\r indep5d5t coils w\nd ^u ! f\r projections4 ,?is armature 0 us$ to r$uce ! spe$ ( ! motor ) ref]5ce to t ( ! g5]ator4 ,fig4 #cjj is /ill ano!r armature ) a great numb] ( indep5d5t circuits clos$ ^u !mselves1 s t all ! dead po9ts on ! armature are done away )1 & ! armature has a l>ge />t+ torque4 ,fig4 #cjc is ano!r type ( armature = a f\r-pole motor b ) coils w\nd ^u a smoo? surface4 ,a numb] ( ^! armatures h holl[ %afts1 z !y h be5 us$ 9 _m ways4 ,figs4 #cji & #caj repres5t armatures to :i* ei!r alt]nat+ or direct curr5t 0 convey$ by means ( slid+ r+s4 ,fig4 #cji consi/s ( a s(t iron body ) a s+le coil w\nd ar\nd x1 ! ends ( ! coil be+ connect$ to two slid+ r+s to :i*1 usually1 direct curr5t 0 convey$4 ,! armature %[n 9 ,fig4 #caj has ?ree insulat$ r+s on a %aft & 0 us$ 9 connection ) two or ?ree phase circuits4 ,all ^! models %[n repres5t e>ly "w1 & ! enl>g$ engrav+s are made f photographs tak5 e>ly 9 #ahhh4 ,!re is a great numb] ( o!r models :i* 7 exhibit$1 b :i* are n br\ght out %>ply 9 ! engrav+1 ,fig4 #big4 ,= example at ,m is a model ( a motor compris+ an armature ) a holl[ %aft w\nd ) two or ?ree coils = two or ?ree-phase circuits2 ! armature 0 arrang$ to be /ation>y & ! g5]at+ circuits 7 connect$ directly to ! g5]ator4 ,ar\nd ! armature is arrang$ to rotate on its %aft a ca/+ =m+ six clos$ circuits4 ,on ! outside ?is ca/+ 0 turn$ smoo? & ! belt 0 plac$ on x = driv+ ) any desir$ appliance4 ,?is also is a v e>ly model4 ,on ! left side ( ! table !re are se5 a l>ge v>iety ( models1 ,n1 ,o1 ,p1 etc41 ) fields ( v>i\s %apes4 ,ea* ( ^! models involves "s di/9ct idea & !y all repres5t gradual developm5t *iefly int]e/+ z %[+ ,mr4 ,tesla's ef=ts to adapt 8 sy/em to ! exi/+ high frequ5cies4 ,on ! "r side ( ! table1 at ,s1 ,t1 are %[n1 on sep>ate supports1 l>g] & m p]fect$ armatures ( comm]cial motors1 & 9 ! space ar\nd ! table a v>iety ( motors & g5]ators supply+ curr5ts to !m 0 exhibit$4 ,! high frequ5cy exhibit embrac$ ,mr4 ,tesla's fir/ orig9al app>atus us$ 9 8 inve/igations4 ,!re 0 exhibit$ a glass tube ) "o lay] ( silk-cov]$ wire w\nd at ! top & a copp] ribbon on ! inside4 ,?is 0 ! fir/ disruptive dis*>ge coil con/ruct$ by him4 ,at ,u is %[n ! disruptive dis*>ge coil exhibit$ by him 9 8 lecture be=e ! ,am]ican ,in/itute ( ,electrical ,eng9e]s1 9 ,may1 #ahia4ah ,at ,v & ,w are %[n "s ( ! fir/ high frequ5cy trans=m]s4 ,a numb] ( v>i\s fields & armatures ( small models ( high frequ5cy app>atus z %[n at ,x & ,y1 & o!rs n visible 9 ! picture1 7 exhibit$4 ,9 ! annex$ space ! dynamo !n us$ by ,mr4 ,tesla at ,columbia ,college 0 exhibit$2 also ano!r =m ( high frequ5cy dynamo us$4 #ah ,see ,"p ,,ii1 ,*ap4 ,,xxvi41 page #ade4 ,illu/ration3 ,,fig4 #caa4 ,9 ?is space also 0 arrang$ a batt]y ( ,leyd5 j>s & 8 l>ge disruptive dis*>ge coil :i* 0 us$ = exhibit+ ! light ph5om5a 9 ! adjo9+ d>k room4 ,! coil 0 op]at$ at only a small fraction ( its capacity1 z ! necess>y cond5s]s & trans=m]s c\ld n be _h & z ,mr4 ,tesla's /ay 0 limit$ to "o week2 not)/&+1 ! ph5om5a 7 ( a /rik+ "*4 ,9 ! room 7 arrang$ two l>ge plates plac$ at a di/ance ( ab\t eighte5 feet f ea* o!r4 ,betwe5 !m 7 plac$ two long tables ) all sorts ( phosphoresc5t bulbs & tubes2 _m ( ^! 7 prep>$ ) great c>e & m>k$ legibly ) ! names :i* w\ld %9e ) phosphoresc5t gl[4 ,among !m 7 "s ) ! names ( ,helmholtz1 ,f>aday1 ,maxwell1 ,h5ry1 ,frankl91 etc4 ,mr4 ,tesla _h also n =gott5 ! greate/ liv+ poet ( 8 own c\ntry1 ,zmaj ,jovan2 two or ?ree 7 prep>$ ) inscriptions1 l ,welcome1 ,electricians1 & produc$ a beautiful effect4 ,ea* repres5t$ "s phase ( ?is "w & /ood = "s individual exp]im5t ( importance4 ,outside ! room 0 ! small batt]y se5 9 ,fig4 #caa1 = ! exhibition ( "s ( ! imp$ance & o!r ph5om5a ( int]e/4 ,?us1 = in/ance1 a ?ick copp] b> b5t 9 ar*$ =m 0 provid$ ) clamps = ! atta*m5t ( lamps1 & a numb] ( lamps 7 kept at inc&esc5ce on ! b>2 !re 0 also a little motor %[n on ! table op]at$ by ! disruptive dis*>ge4 ,z w be rememb]$ by ^? :o visit$ ! ,exposition1 ! ,we/+h\se ,company made a l9e exhibit ( ! v>i\s comm]cial motors ( ! ,tesla sy/em1 :ile ! twelve g5]ators 9 ,ma*9]y ,hall 7 ( ! two-phase type con/ruct$ = di/ribut+ light & p[]4 ,mr4 ,tesla1 also exhibit$ "s models ( 8 oscillators4 ,,*apt] ,,xliii4 ,,! ,,tesla ,,me*anical ,,& ,,electrical ,,oscillators4 ,on ! ev5+ ( ,friday1 ,augu/ #be1 #ahic1 ,mr4 ,tesla deliv]$ a lecture on 8 me*anical & electrical oscillators1 be=e ! memb]s ( ! ,electrical ,congress1 9 ! hall adjo9+ ! ,agricultural ,build+1 at ! ,_w's ,fair1 ,*icago4 ,besides ! app>atus 9 ! room1 he employ$ an air compressor1 :i* 0 driv5 by an electric motor4 ,mr4 ,tesla 0 introduc$ by ,dr4 ,eli%a ,gray1 & began by /at+ t ! problem he _h set out to solve 0 to con/ruct1 fir/1 a me*anism :i* w\ld produce oscillations ( a p]fectly con/ant p]iod indep5d5t ( ! pressure ( /eam or air appli$1 )9 ! wide/ limits1 & also indep5d5t ( frictional losses & load4 ,secondly1 to produce electric curr5ts ( a p]fectly con/ant p]iod indep5d5tly ( ! work+ conditions1 & to produce ^! curr5ts ) me*anism :i* %\ld be reliable & positive 9 its action )\t resort+ to sp>k gaps & breaks4 ,?is he successfully accompli%$ 9 8 app>atus1 & ) ?is app>atus1 n[1 sci5tific m5 w be provid$ ) ! necess>ies = c>ry+ on inve/igations ) alt]nat+ curr5ts ) great precision4 ,^! two inv5tions ,mr4 ,tesla call$1 q appropriately1 a me*anical & an electrical oscillator1 respectively4 ,! =m] is sub/antially con/ruct$ 9 ! foll[+ way4 ,!re is a pi/on 9 a cyl9d] made to reciprocate automatically by prop] dispositions ( p>ts1 simil> to a reciprocat+ tool4 ,mr4 ,tesla po9t$ out t he _h done a great deal ( "w 9 p]fect+ 8 app>atus s t x w\ld "w effici5tly at su* high frequ5cy ( reciprocation z he contemplat$1 b he did n dwell on ! _m difficulties enc\nt]$4 ,he exhibit$1 h[ev]1 ! pieces ( a /eel arbor :i* _h be5 actually torn ap>t :ile vibrat+ aga9/ a m9ute air cu%ion4 ,) ! pi/on above ref]r$ to !re is associat$ 9 "o ( 8 models 9 an indep5d5t *amb] an air spr+1 or da% pot1 or else he obta9s ! spr+ )9 ! *amb]s ( ! oscillator itself4 ,to appreciate ! beauty ( ?is x is only necess>y to say t 9 t disposition1 z he %[$ x1 no matt] :at ! rigidity ( ! spr+ & no matt] :at ! weight ( ! mov+ p>ts1 9 o!r words1 no matt] :at ! p]iod ( vibrations1 ! vibrations ( ! spr+ are always iso*ron\s ) ! appli$ pressure4 ,ow+ to ?is1 ! results obta9$ ) ^! vibrations are truly wond]ful4 ,mr4 ,tesla provides = an air spr+ ( trem5d\s rigidity1 & he is enabl$ to vibrate big weights at an enorm\s rate1 consid]+ ! in]tia1 ow+ to ! recoil ( ! spr+4 ,?us1 = in/ance1 9 "o ( ^! exp]im5ts1 he vibrates a weight ( approximately #bj p\nds at ! rate ( ab\t #hj p] second & ) a /roke ( ab\t #g_/h in*1 b by %ort5+ ! /roke ! weight c\ld be vibrat$ _m hundr$ times1 & has be51 9 o!r exp]im5ts4 ,to />t ! vibrations1 a p[]ful bl[ is /ruck1 b ! adju/m5t c be s made t only a m9ute ef=t is requir$ to />t1 &1 ev5 )\t any special provision x w />t by m]ely turn+ on ! pressure sudd5ly4 ,! vibration be+1 ( c\rse1 iso*ron\s1 any *ange ( pressure m]ely produces a %ort5+ or l5g!n+ ( ! /roke4 ,mr4 ,tesla %[$ a numb] ( v cle> draw+s1 illu/rat+ ! con/ruction ( ! app>atus f :i* its work+ 0 pla9ly disc]nible4 ,special provisions are made s z to equalize ! pressure )9 ! da% pot & ! out] atmosph]e4 ,= ?is purpose ! inside *amb]s ( ! da% pot are arrang$ to communicate ) ! out] atmosph]e s t no matt] h[ ! temp]ature ( ! enclos$ air might v>y1 x /ill reta9s ! same mean d5sity z ! out] atmosph]e1 & by ?is means a spr+ ( con/ant rigidity is obta9$4 ,n[1 ( c\rse1 ! pressure ( ! atmosph]e may v>y1 & ?is w\ld v>y ! rigidity ( ! spr+1 & consequ5tly ! p]iod ( vibration1 & ?is feature con/itutes "o ( ! great beauties ( ! app>atus2 =1 z ,mr4 ,tesla po9t$ out1 ?is me*anical sy/em acts exactly l a /r+ tightly /ret*$ betwe5 two po9ts1 & ) fix$ nodes1 s t slight *anges ( ! t5sion d n 9 ! lea/ alt] ! p]iod ( oscillation4 ,! applications ( su* an app>atus are1 ( c\rse1 num]\s & obvi\s4 ,! fir/ is1 ( c\rse1 to produce electric curr5ts1 & by a numb] ( models & app>atus on ! lecture plat=m1 ,mr4 ,tesla %[$ h[ ?is c\ld be c>ri$ out 9 practice by comb9+ an electric g5]ator ) 8 oscillator4 ,he po9t$ out :at conditions mu/ be obs]v$ 9 ord] t ! p]iod ( vibration ( ! electrical sy/em might n di/urb ! me*anical oscillation 9 su* a way z to alt] ! p]iodicity1 b m]ely to %ort5 ! /roke4 ,he comb9es a cond5s] ) a self-induction1 & gives to ! electrical sy/em ! same p]iod z t at :i* ! ma*9e itself oscillates1 s t bo? toge!r !n fall 9 /ep & electrical & me*anical resonance is obta9$1 & ma9ta9$ absolutely unv>i$4 ,next he %[$ a model ( a motor ) delicate :eelwork1 :i* 0 driv5 by ^! curr5ts at a con/ant spe$1 no matt] :at ! air pressure appli$ 01 s t ?is motor c\ld be employ$ z a clock4 ,he also %[$ a clock s con/ruct$ t x c\ld be atta*$ to "o ( ! oscillators1 & w\ld keep absolutely correct "t4 ,ano!r curi\s & int]e/+ feature :i* ,mr4 ,tesla po9t$ out 0 t1 in/ead ( controll+ ! motion ( ! reciprocat+ pi/on by means ( a spr+1 s z to obta9 iso*ron\s vibration1 he 0 actually able to control ! me*anical motion by ! natural vibration ( ! electro-magnetic sy/em1 & he said t ! case 0 a v simple "o1 & 0 q analog\s to t ( a p5dulum4 ,?us1 suppos+ we _h a p5dulum ( great weight1 pref]ably1 :i* w\ld be ma9ta9$ 9 vibration by =ce1 p]iodically appli$2 n[ t =ce1 no matt] h[ x might v>y1 al?\gh x w\ld oscillate ! p5dulum1 w\ld h no control ov] its p]iod4 ,mr4 ,tesla also describ$ a v int]e/+ ph5om5on :i* he illu/rat$ by an exp]im5t4 ,by means ( ?is new app>atus1 he is able to produce an alt]nat+ curr5t 9 :i* ! ,e4 ,m4 ,f4 ( ! impulses 9 "o direction prepond]ates ov] t ( ^? 9 ! o!r1 s t !re is produc$ ! effect ( a direct curr5t4 ,9 fact he express$ ! hope t ^! curr5ts w\ld be capable ( application 9 _m in/ances1 s]v+ z direct curr5ts4 ,! pr9ciple involv$ 9 ?is prepond]at+ ,e4 ,m4 ,f4 he expla9s 9 ?is way3 ,suppose a conductor is mov$ into ! magnetic field & !n sudd5ly )drawn4 ,if ! curr5t is n ret>d$1 !n ! "w p]=m$ w be a m]e fractional "o2 b if ! curr5t is ret>d$1 !n ! magnetic field acts z a spr+4 ,imag9e t ! motion ( ! conductor is arre/$ by ! curr5t g5]at$1 & t at ! in/ant :5 x /ops to move into ! field1 !re is /ill ! maximum curr5t fl[+ 9 ! conductor2 !n ?is curr5t w1 accord+ to ,l5z's law1 drive ! conductor out ( ! field aga91 & if ! conductor has no resi/ance1 !n x w\ld leave ! field ) ! velocity x ent]$ x4 ,n[ x is cle> t if1 in/ead ( simply dep5d+ on ! curr5t to drive ! conductor out ( ! field1 ! me*anically appli$ =ce is s tim$ t x helps ! conductor to get out ( ! field1 !n x might leave ! field ) high] velocity ?an x ent]$ x1 & ?us "o impulse is made to prepond]ate 9 ,e4 ,m4 ,f4 ov] ! o!r4 ,) a curr5t ( ?is nature1 ,mr4 ,tesla en]giz$ magnets /rongly1 & p]=m$ _m int]e/+ exp]im5ts be>+ out ! fact t "o ( ! curr5t impulses prepond]ates4 ,among !m 0 "o 9 :i* he atta*$ to 8 oscillator a r+ magnet ) a small air gap betwe5 ! poles4 ,?is magnet 0 oscillat$ up & d[n #hj times a second4 ,a copp] disc1 :5 ins]t$ )9 ! air gap ( ! r+ magnet1 0 br\ght into rapid rotation4 ,mr4 ,tesla rem>k$ t ?is exp]im5t also seem$ to demon/rate t ! l9es ( fl[ ( curr5t ?r\gh a metallic mass are di/urb$ by ! pres5ce ( a magnet 9 a mann] q indep5d5tly ( ! s-call$ ,hall effect4 ,he %[$ also a v int]e/+ me?od ( mak+ a connection ) ! oscillat+ magnet4 ,?is 0 accompli%$ by atta*+ to ! magnet small insulat$ /eel rods1 & connect+ to ^! rods ! ends ( ! en]giz+ coil4 ,z ! magnet 0 vibrat$1 /ation>y nodes 7 produc$ 9 ! /eel rods1 & at ^! po9ts ! t]m9als ( a direct curr5t s\rce 7 atta*$4 ,mr4 ,tesla also po9t$ out t "o ( ! uses ( curr5ts1 su* z ^? produc$ 9 8 app>atus1 w\ld be to select any giv5 "o ( a numb] ( devices connect$ to ! same circuit by pick+ out ! vibration by resonance4 ,!re is inde$ little d\bt t ) ,mr4 ,tesla's devices1 h>monic & syn*ron\s telegraphy w receive a fre% impetus1 & va/ possibilities are aga9 op5$ up4 ,mr4 ,tesla 0 v mu* elat$ ov] 8 late/ a*ievem5ts1 & said t he hop$ t 9 ! h&s ( practical1 z well z sci5tific m51 ! devices describ$ by him w\ld yield important results4 ,he laid special /ress on ! facility n[ af=d$ = inve/igat+ ! effect ( me*anical vibration 9 all directions1 & also %[$ t he _h obs]v$ a numb] ( facts 9 connection ) iron cores4 ,illu/ration3 ,,fig4 #cab4 ,! engrav+1 ,fig4 #cab1 %[s1 9 p]spective1 "o ( ! =ms ( app>atus us$ by ,mr4 ,tesla 9 8 e>li] inve/igations 9 ?is field ( "w1 & its int]ior con/ruction is made pla9 by ! sectional view %[n 9 ,fig4 #cac4 ,x w be not$ t ! pi/on ,p is fitt$ into ! holl[ ( a cyl9d] ,c :i* is provid$ ) *annel ports ,o ,o1 & ,i1 ext5d+ all ar\nd ! inside surface4 ,9 ?is p>ticul> app>atus !re are two *annels ,o ,o = ! outlet ( ! work+ fluid & "o1 ,i1 = ! inlet4 ,! pi/on ,p is provid$ ) two slots ,s ,s' at a c>efully det]m9$ di/ance1 "o f ! o!r4 ,! tubes ,t ,t :i* are screw$ into ! holes drill$ into ! pi/on1 e/abli% communication betwe5 ! slots ,s ,s' & *amb]s on ea* side ( ! pi/on1 ea* ( ^! *amb]s connect+ ) ! slot :i* is remote f x4 ,! pi/on ,p is screw$ tightly on a %aft ,a :i* passes ?r\gh fitt+ boxes at ! end ( ! cyl9d] ,c4 ,! boxes project to a c>efully det]m9$ di/ance into ! holl[ ( ! cyl9d] ,c1 ?us det]m9+ ! l5g? ( ! /roke4 ,surr\nd+ ! :ole is a jacket ,j4 ,?is jacket acts *iefly to dim9i% ! s\nd produc$ by ! oscillator & z a jacket :5 ! oscillator is driv5 by /eam1 9 :i* case a some:at diff]5t arrangem5t ( ! magnets is employ$4 ,! app>atus "h illu/rat$ 0 int5d$ = demon/ration purposes1 air be+ us$ z mo/ conv5i5t = ?is purpose4 ,a magnetic frame ,m ,m is fa/5$ s z to closely surr\nd ! oscillator & is provid$ ) en]giz+ coils :i* e/abli% two /rong magnetic fields on opposite sides4 ,! magnetic frame is made up ( ?9 %eet iron4 ,9 ! int5sely conc5trat$ field ?us produc$1 !re are arrang$ two pairs ( coils ,h ,h support$ 9 metallic frames :i* are screw$ on ! %aft ,a ( ! pi/on & h additional be>+s 9 ! boxes ,b ,b on ea* side4 ,! :ole is m\nt$ on a metallic base re/+ on two wood5 blocks4 ,illu/ration3 ,,fig4 #cac4 ,! op]ation ( ! device is z foll[s3 ,! work+ fluid be+ admitt$ ?r\gh an inlet pipe to ! slot ,i & ! pi/on be+ suppos$ to be 9 ! position indicat$1 x is suffici5t1 ?\gh n necess>y1 to give a g5tle tap on "o ( ! %aft ends protrud+ f ! boxes ,b4 ,assume t ! motion imp>t$ be su* z to move ! pi/on to ! left 7:5 look+ at ! diagram7 !n ! air ru%es ?r\gh ! slot ,s' & tube ,t into ! *amb] to ! left4 ,! pressure n[ drives ! pi/on t[>ds ! "r &1 ow+ to its in]tia1 x ov]%oots ! position ( equilibrium & all[s ! air to ru% ?r\gh ! slot ,s & tube ,t into ! *amb] to ! "r1 :ile ! communication to ! left h& *amb] is cut (f1 ! air ( ! latt] *amb] escap+ ?r\gh ! outlet ,o on ! left4 ,on ! return /roke a simil> op]ation takes place on ! "r h& side4 ,?is oscillation is ma9ta9$ cont9u\sly & ! app>atus p]=ms vibrations f a sc>cely p]ceptible quiv] am\nt+ to no m ?an #a ( an in*1 up to vibrations ( a little ov] #c_/h ( an in*1 accord+ to ! air pressure & load4 ,x is inde$ int]e/+ to see h[ an inc&esc5t lamp is kept burn+ ) ! app>atus %[+ a sc>cely p]ceptible quiv]4 ,to p]fect ! me*anical "p ( ! app>atus s t oscillations are ma9ta9$ economically 0 "o ?+1 & ,mr4 ,tesla h9t$ 9 8 lecture at ! great difficulties he _h fir/ enc\nt]$ to accompli% ?is4 ,b to produce oscillations :i* w\ld be ( con/ant p]iod 0 ano!r task ( no mean proportions4 ,z already po9t$ out1 ,mr4 ,tesla obta9s ! con/ancy ( p]iod 9 ?ree di/9ct ways4 ,?us1 he provides prop]ly calculat$ *amb]s1 z 9 ! case illu/rat$1 9 ! oscillator itself2 or he associates ) ! oscillator an air spr+ ( con/ant resili5ce4 ,b ! mo/ int]e/+ ( all1 p]haps1 is ! ma9t5ance ( ! con/ancy ( oscillation by ! reaction ( ! electromagnetic "p ( ! comb9ation4 ,mr4 ,tesla w9ds 8 coils1 by pref]5ce1 = high t5sion & associates ) !m a cond5s]1 mak+ ! natural p]iod ( ! comb9ation fairly approximat+ to ! av]age p]iod at :i* ! pi/on w\ld oscillate )\t any p>ticul> provision be+ made = ! con/ancy ( p]iod "u v>y+ pressure & load4 ,z ! pi/on ) ! coils is p]fectly free to move1 x is extremely susceptible to ! influ5ce ( ! natural vibration set up 9 ! circuits ( ! coils ,h ,h4 ,! me*anical effici5cy ( ! app>atus is v high ow+ to ! fact t friction is r$uc$ to a m9imum & ! weights :i* are mov$ are small2 ! output ( ! oscillator is !re=e a v l>ge "o4 ,!oretically consid]$1 :5 ! v>i\s advantages :i* ,mr4 ,tesla holds out are exam9$1 x is surpris+1 consid]+ ! simplicity ( ! arrangem5t1 t no?+ 0 done 9 ?is direction be=e4 ,no d\bt _m inv5tors1 at "o "t or o!r1 h ent]ta9$ ! idea ( g5]at+ curr5ts by atta*+ a coil or a magnetic core to ! pi/on ( a /eam eng9e1 or g5]at+ curr5ts by ! vibrations ( a tun+ =k1 or simil> devices1 b ! disadvantages ( su* arrangem5ts f an eng9e]+ /&po9t mu/ be obvi\s4 ,mr4 ,tesla1 h[ev]1 9 ! introductory rem>ks ( 8 lecture1 po9t$ out h[ by a s]ies ( conclusions he 0 driv5 to take up ?is new l9e ( "w by ! necessity ( produc+ curr5ts ( con/ant p]iod & z a result ( 8 endeavors to ma9ta9 electrical oscillation 9 ! mo/ simple & economical mann]4 ,,index4 ,alt]nate ,curr5t ,electro/atic ,app>atus #cib ,alt]nat+ ,curr5t ,g5]ators = ,high ,frequ5cy #aeb1 #cgd1 #bbd ,alt]nat+ ,motors & ,trans=m]s #g ,am]ican ,in/itute ,electrical ,eng9e]s ,lecture #ade ,an?ony1 ,w4 ,a41 ,te/s ( ,tesla ,motors #h ,app>atus = ,produc+ ,high ,vacua #bgf ,arc ,light+1 ,tesla ,direct1 ,sy/em #dea ,auxili>y ,bru% ,regulation #dch ,biography1 ,tesla #d ,bru%1 ,anti-,sp>k+ #dcb ,bru%1 ,?ird1 ,regulation #dch ,bru%1 ,ph5om5a 9 ,high ,vacuum #bbf ,c>borundum ,button = ,tesla ,lamps #adj1 #bec ,commutator1 ,anti-,sp>k+ #dcb ,comb9ation ( ,syn*roniz+ & ,torque ,motor #ie ,cond5s]s ) ,plates 9 ,oil #dah ,conv]sion ) ,disruptive ,dis*>ge #aic1 #bjd1 #cjc ,curr5t or ,dynamic ,electricity ,ph5om5a #cbg ,direct ,curr5t ,arc ,light+ #dea ,dis*>g]s1 ,=ms ( #cje ,disruptive ,dis*>ge ,coil #bjg1 #bba ,disruptive ,dis*>ge ,ph5om5a #bab ,dynamos1 ,improv$ ,direct ,curr5t #ddh ,e>ly ,phase ,motors #dgg ,effects ) ,high ,frequ5cy & ,high ,pot5tial ,curr5ts #aai ,electrical ,congress ,lecture1 ,*icago4 #dhf ,electric ,resonance #cdj ,electric ,dis*>ges 9 ,vacuum ,tubes #cif ,electrolytic ,regi/]+ ,met] #dbj ,eye1 ,obs]vations on ! #bid ,flames1 ,electro/atic1 ,non-,consum+ #aff1 #bgb ,=bes ,unipol> ,g5]ator #dfh1 #dgd ,frankl9 ,in/itute ,lecture #bid ,g5]ators1 ,pyromagnetic #dbi ,high ,pot5tial1 ,high ,frequ5cy3 ,bru% ,ph5om5a 9 ,high ,vacuum #bbf ,c>borundum ,buttons #adj1 #bec ,disruptive ,dis*>ge ,ph5om5a #bab ,flames1 ,electro/atic1 ,non-,consum+ #aff1 #bgb ,imp$ance1 ,novel ,ph5om5a #aid1 #cch ,light+ ,lamps ,?r\gh ,body #cei ,lum9\s ,effects ) ,gases #cfh ,massage ) ,curr5ts #cid ,motor ) ,s+le ,wire #bcd1 #ccj ,no ,wire ,motors #bce ,oil ,insulation ( ,induction ,coils #agc1 #bba ,ozone1 ,production ( #aga ,phosphoresc5ce #cfg ,physiological ,effects #afb1 #cid ,resonance #cdj ,sp9n+ ,filam5t #afh ,/ream+ ,dis*>ges ( ,high ,t5sion ,coil #aee1 #afc ,telegraphy )\t ,wires #cdf ,imp$ance1 ,novel ,ph5om5a #aid1 #cch ,improvem5ts 9 ,unipol> ,g5]ators #dfe ,improv$ ,direct ,curr5t ,dynamos & ,motors #ddh ,induction ,motors #ib ,in/itution ,electrical ,eng9e]s ,lecture #aih ,lamps & ,motor op]at$ on a ,s+le ,wire #ccj ,lamps ) ,s+le ,/raight ,fib] #ahc ,lamps conta9+ only a ,gas #ahh ,lamps ) ,refractory ,button #agg1 #bci1 #cfj ,lamps = ,simple ,phosphoresc5ce #ahg1 #bhb1 #cfd ,lecture1 ,tesla be=e3 ,am]ican ,in/itute ,electrical ,eng9e]s #ade ,royal ,in/itution #abd ,in/itution ,electrical ,eng9e]s #aih ,frankl9 ,in/itute & ,national ,electric ,light ,association #bid ,electrical ,congress1 ,*icago #dhf ,light+ ,lamps ,?r\gh ! ,body #cei ,light ,ph5om5a ) ,high ,frequ5cies #cdi ,lum9\s ,effects ) ,gases at ,l[-,pressure #cfh ,magnetic ,lag ,motor #fg ,massage ) ,curr5ts ( ,high ,frequ5cy #cid ,me*anical & ,electrical ,oscillators #dhf ,me?od ( obta9+ ,direct f ,alt]nat+ curr5ts #dji ,me?od ( obta9+ ,diff]5ce ( ,phase by ,magnetic ,%ield+ #ga ,motors3 ,) ,circuits ( ,diff]5t ,resi/ance #gi ,) ,clos$ ,conductors #i ,comb9ation ( ,syn*roniz+ & ,torque #ie ,) ,cond5s] 9 ,armature ,circuit #aja ,) ,cond5s] 9 "o ( ! ,field ,circuits #ajf ,) ,co9cid+ ,maxima ( ,magnetic ,effect 9 ,armature & ,field #hc ,) ,curr5t ,lag ,artificially ,secur$ #eh ,e>ly ,phase #dgg ,) ,equal ,magnetic ,en]gies 9 ,field & ,armature #ha ,or ,g5]ator1 obta9+ ,desir$ ,spe$ ( #cf ,improv$ ,direct ,curr5t #ddh ,induction #ib ,magnetic ,lag #fg ,no ,wire #bce ,) ,phase ,diff]5ce 9 ,magnetization ( ,inn] & ,out] ,p>ts ( ,core #hh ,regulator = ,rot>y ,curr5t #de ,s+le ,circuit1 ,self-/>t+ ,syn*roniz+ #ej ,s+le ,phase #gf ,) ,s+le ,wire to ,g5]ator #bcd1 #ccj ,syn*roniz+ #i ,!rmo-,magnetic #dbd ,utiliz+ ,cont9u\s ,curr5t ,g5]ators #ca ,national ,electric ,light ,association ,lecture #bid ,no ,wire ,motor #bce ,obs]vations on ! ,eye #bid ,oil1 ,cond5s]s ) ,plates 9 #dah ,oil ,insulation ( ,induction ,coils #agc1 #bba ,oscillators1 ,me*anical & ,electrical #dhf ,ozone1 ,production ( #aga ,ph5om5a ,produc$ by ,electro/atic ,=ce #cah ,phosphoresc5ce & ,sulphide ( ,z9c #cfg ,physiological ,effects ( ,high ,frequ5cy #afb1 #cid ,polyphase ,sy/ems #bf ,polyphase ,trans=m] #aji ,pyromagnetic ,g5]ators #dbi ,regulator = ,rot>y ,curr5t ,motors #de ,resonance1 ,electric1 ,ph5om5a ( #cdj ,resultant ,attraction #g ,rotat+ ,field ,trans=m]s #i ,rotat+ ,magnetic ,field #i ,royal ,in/itution ,lecture #abd ,scope ( ,lectures #aai ,s+le ,phase ,motor #gf ,s+le ,circuit1 ,self-,/>t+ ,syn*roniz+ ,motors #ej ,sp9n+ ,filam5t ,effects #afh ,/ream+ ,dis*>ges ( ,high ,t5sion ,coil #aee1 #afc ,syn*roniz+ ,motors #i ,telegraphy )\t ,wires #bdf ,trans=m] ) ,%ield betwe5 ,prim>y & ,second>y #aac ,!rmo-,magnetic ,motors #dbd ,?omson1 ,j4 ,j41 on ,vacuum ,tubes #cig1 #djb1 #djf ,?omson1 ,sir ,w41 ,curr5t ,accumulator #dga ,trans=m]s3 ,alt]nat+ #g ,magnetic ,%ield #aac ,polyphase #aji ,rotat+ ,field #i ,tubes3 ,coat$ ) ,yttria1 etc4 #ahg ,coat$ ) ,sulphide ( ,z9c1 etc4 #bij1 #cfg ,unipol> ,g5]ators #dfe ,unipol> ,g5]ator1 ,=bes #dfh1 #dgd ,yttria1 ,coat$ ,tubes #ahg ,z9c1 ,tubes ,coat$ ) ,sulphide ( #cfg