,,w>n+3 ,?is book ( "o hundr$ ye>s ago describes exp]im5ts :i* are too dang]\s to attempt by ei!r adults or *ildr54 ,x is publi%$ = hi/orical int]e/ only4 ,,! ,,h[-,,to-,,d-,,x ,,books ,,electricity ,,= ,,boys ,illu/ration3 ,fig4 #a4 ,,"w ,,b5* ,,! ,,h[-,,to-,,d-,,x ,,books ,,electricity ,,= ,,boys ,a work+ guide1 9 ! successive /eps ( electricity1 describ$ 9 simple t]ms ,,) ,,_m ,,orig9al ,,illu/rations ,by ,j4 ,s4 ,,z]be1 ,m4,e4 ,,au?or ,,( ,,c>p5try ,,= ,,boys ,,practical ,,me*anics ,,= ,,boys ,illu/ration3 ,pr9t]'s ,m>k ,,! ,,new ,,york ,,book ,,company ,,new ,,york ,,copyright1 #aiad1 ,,by ,,! ,,new ,,york ,,book ,,company ,,cont5ts ,,introductory ,page #a ,i4 ,,electricity ,,consid]$4 ,,brief ,,hi/orical ,,ev5ts ,page #e ,! ,/udy ( ,electricity4 ,fir/ ,hi/orical ,acc\nts4 ,bottl+ ,electricity4 ,discov]y ( ,galvanic ,electricity4 ,electro-motive ,=ce4 ,measur+ ,in/rum5ts4 ,rapidity ( ,mod]n ,progress4 ,h[ to ,acquire ! ,va/ ,k4 ,! ,means ,employ$4 ,,ii4 ,,:at ,,tools ,,& ,,app>atus ,,are ,,ne$$ ,page #aa ,prep>+ ! ,work%op4 ,uses ( ,our ,work%op4 ,:at to ,build4 ,:at to ,le>n4 ,uses ( ! ,electrical ,devices4 ,tools4 ,magnet-w9d+ ,reel4 ,,iii4 ,,magnets1 ,,coils1 ,,armatures1 ,,etc4 ,page #ah ,! ,two ,k9ds ( ,magnets4 ,p]man5t ,magnets4 ,electro-,magnets4 ,magnetism4 ,mat]ials = ,magnets4 ,non-magnetic ,mat]ial4 ,action ( a ,second ,magnet4 ,:at ,nor? & ,s\? ,pole ,mean4 ,repulsion & ,attraction4 ,positives & ,negatives4 ,magnetic ,l9es ( ,=ce4 ,! ,e>? z a ,magnet4 ,:y ! ,compass ,po9ts ,nor? & ,s\?4 ,peculi>ity ( a ,magnet4 ,action ( ! ,electro-,magnet4 ,ext]ior ,magnetic ,influ5ce ,ar\nd a ,wires ,c>ry+ a ,curr5t4 ,p>allel ,wires4 ,,iv4 ,,frictional1 ,,voltaic ,,or ,,galvanic ,,& ,,electro-,,magnetic ,,electricity ,page #bi ,?ree ,electrical ,s\rces4 ,frictional ,electricity4 ,leyd5 ,j>4 ,voltaic or ,galvanic ,electricity4 ,voltaic ,pile2 ,h[ ,made4 ,plus & ,m9us ,signs4 ,! ,common ,prim>y ,cell4 ,batt]y ,resi/ance4 ,electrolyte & ,curr5t4 ,electro-magnetic ,electricity4 ,magnetic ,radiation4 ,diff]5t ,k9ds ( ,dynamos4 ,direct ,curr5t ,dynamos4 ,simple ,magnet ,con/ruction4 ,h[ to ,w9d4 ,! ,dynamo ,fields4 ,! ,armature4 ,armature ,w9d+s4 ,m\nt+ ! ,armature4 ,! ,commutator4 ,commutator ,bru%es4 ,dynamo ,w9d+s4 ,! ,field4 ,s]ies-w\nd ,field4 ,%unt-w\nd4 ,comp\nd-w\nd4 ,v4 ,,h[ ,,to ,,detect ,,& ,,measure ,,electricity ,page #di ,measur+ ,in/rum5ts4 ,! ,detector4 ,direction ( ,curr5t4 ,simple ,curr5t ,detector4 ,h[ to ,place ! ,detector4 ,diff]5t ,ways to ,measure a ,curr5t4 ,! ,sulphuric ,acid ,voltamet]4 ,! ,copp] ,voltamet]4 ,! ,galvanoscope ,electro-magnetic ,me?od4 ,! ,calorimet]4 ,! ,light ,me?od4 ,! ,pref]r$ ,me?od4 ,h[ to ,make a ,sulphuric ,acid ,voltamet]4 ,h[ to ,make a ,copp] ,voltamet]4 ,objections to ! ,calorimet]4 ,,vi4 ,,volts1 ,,amp]es1 ,,ohms ,,& ,,watts ,page #fj ,und]/&+ ,t]ms4 ,int5sity & ,quantity4 ,voltage4 ,amp]age ,mean+ ( ,watts & ,kil[att4 ,a ,/&>d ( ,measurem5t4 ,! ,amp]e ,/&>d4 ,! ,voltage ,/&>d4 ,! ,ohm4 ,calculat+ ! ,voltage4 ,,vii4 ,,pu% ,,buttons1 ,,swit*es1 ,,annunciators1 ,,bells ,,& ,,l ,,app>atus ,page #fe ,simple ,swit*es4 ,a ,two-,pole ,swit*4 ,d\ble-,pole ,swit*4 ,slid+ ,swit*4 ,rev]s+ ,swit*4 ,pu% ,buttons4 ,electric ,bells4 ,h[ ,made4 ,h[ ,op]at$4 ,annunciators4 ,burgl> ,al>m4 ,wire ,circuit+4 ,circuit+ ,sy/em ) ,two ,bells & ,pu% ,buttons4 ,! ,pu% ,buttons1 ,annunciators & ,bells4 ,wir+ ,up a ,h\se4 ,,viii4 ,,accumulators1 ,,/orage ,,or ,,second>y ,,batt]ies ,page #hb ,/or+ ,up ,electricity4 ,! ,accumulator4 ,accumulator ,plates4 ,! ,grid4 ,! ,negative ,pole4 ,connect+ ,up ! ,plates4 ,*>g+ ! ,cells4 ,! ,initial ,*>ge4 ,! ,*>g+ ,curr5t4 ,,ix4 ,,! ,,telegraph ,page #ij ,me*anism 9 ,telegraph ,circuit4 ,! ,s5d+ ,key4 ,! ,s\nd]4 ,connect+ ,up ! ,key & ,s\nd]4 ,two ,/ations 9 ,circuit4 ,! ,d\ble ,click4 ,illu/rat+ ! ,dot & ! ,da%4 ,! ,morse ,telegraph ,code4 ,example 9 ,use4 ,x4 ,,high-,,t5sion ,,app>atus1 ,,cond5s]s1 ,,etc4 ,page #ih ,induction4 ,l[ & ,high ,t5sion4 ,ela/ic ,prop]ty ( ,electricity4 ,! ,cond5s]4 ,connect+ up a ,cond5s]4 ,! ,int]rupt]4 ,uses ( ,high-t5sion ,coils4 ,,xi4 ,,wireless ,,telegraphy ,page #ajd ,telegraph+ ,)\t ,wires4 ,surg+ ,"* ( ,high-t5sion ,curr5ts4 ,! ,coh]]4 ,h[ ,made4 ,! ,decoh]]4 ,! ,s5d+ ,app>atus4 ,! ,receiv+ ,app>atus4 ,h[ ! ,circuits are ,=m$4 ,,xii4 ,,! ,,telephone ,page #aaj ,vibrations4 ,! ,ac\/ic ,telephone4 ,s\nd ,waves4 ,he>+ ,electricity4 ,! ,diaphragm 9 a ,magnetic ,field4 ,a ,simple ,telephone ,circuit4 ,h[ to ,make a ,telephone4 ,telephone ,connections4 ,complete ,in/allation4 ,! ,microphone4 ,light ,contact ,po9ts4 ,h[ to ,make a ,microphone4 ,microphone1 ! ,fa!r ( ! ,transmitt]4 ,automatic ,cut-outs = ,telephones4 ,complete ,circuit+ ) ,transmitt]s4 ,,xiii4 ,,electrolysis1 ,,wat] ,,purification1 ,,electroplat+ ,page #abc ,decompos+ ,liquids4 ,mak+ ,hydrog5 & ,oxyg54 ,purify+ ,wat]4 ,ru/4 ,oxyg5 z a ,purifi]4 ,composition ( ,wat]4 ,common ,air ,n a ,good ,purifi]4 ,pure ,oxyg5 a ,wat] ,purifi]4 ,! ,use ( ,hydrog5 9 ,purification4 ,alum9um ,electrodes4 ,electric ,h& ,purifi]4 ,purification & ,sep>ation ( ,metals4 ,electroplat+4 ,plat+ ,iron ) ,copp]4 ,direction ( ,curr5t4 ,,xiv4 ,,electric ,,heat+4 ,,!rmo-,,electricity ,page #ace ,g5]at+ ,heat 9 a ,wire4 ,resi/ance ( ,sub/ances4 ,signs ( ,connectors4 ,comp>ison ( ,metals4 ,a ,simple ,electric ,heat]4 ,h[ to ,arrange = ,quantity ( ,curr5t ,us$4 ,an ,electric ,iron4 ,!rmo-,electricity ,conv]t+ ,heat ,directly into ,electricity ,metals4 ,electric1 ,positive1 ,negative4 ,!rmo-electric ,c\pl]4 ,,xv4 ,,alt]nat+ ,,curr5ts1 ,,*ok+ ,,coil1 ,,trans=m] ,page #ade ,direct ,curr5t4 ,alt]nat+ ,curr5t4 ,! ,magnetic ,field4 ,action ( a ,magnetiz$ ,wire4 ,! ,movem5t ( a ,curr5t 9 a ,*>g$ ,wire4 ,curr5t ,rev]s+ ,itself4 ,self-,induction4 ,bru%es 9 a ,direct ,curr5t ,dynamo3 ,alt]nat+1 ,positive & ,negative ,poles4 ,h[ an ,alt]nat+ ,curr5t ,dynamo is ,made4 ,! ,w9d+s4 ,! ,armature ,wires4 ,*ok+ ,coils4 ,! ,trans=m]4 ,h[ ! ,voltage is ,det]m9$4 ,voltage & ,amp]age 9 ,trans=m]s4 ,,xvi4 ,,electric ,,light+ ,page #afa ,e>ly conditions4 ,fuels4 ,rev]sibility ( ,dynamo4 ,electric arc4 ,me*anism to ma9ta9 ! arc4 ,resi/ance coil4 ,p>allel c>bons = mak+ arc4 ,s]ies curr5t4 ,inc&esc5t sy/em4 ,multiple circuit4 ,subdivision ( electric light4 ,! filam5t4 ,! glass bulb4 ,metallic filam5ts4 ,vapor lamps4 ,directions = improvem5ts4 ,heat 9 electric light+4 ,curi\s sup]/itions conc]n+ electricity4 ,magnetism4 ,amb]4 ,discov]y ( ! prop]ties ( a magnet4 ,electricity 9 m\nta9 regions4 ,e>ly beliefs z to magnetism & electricity4 ,! lightn+ rod4 ,prote/s aga9/ us+ x4 ,pl9y's explanation ( electricity4 ,,xvii4 ,,p[]1 ,,& ,,v>i\s ,,o!r ,,electrical ,,manife/ations ,page #age ,e>ly beliefs conc]n+ ! dynamo4 ,exp]im5ts ) magnets4 ,physical action ( dynamo & motor4 ,electrical influ5ce 9 w9d+s4 ,comp>+ motor & dynamo4 ,h[ ! curr5t acts 9 a dynamo4 ,its =ce 9 a motor4 ,loss 9 p[] transmission4 ,! f\r ways 9 :i* p[] is dissipat$4 ,disadvantages ( electric p[]4 ,its advantages4 ,transmission ( en]gy4 ,high voltages4 ,! trans=m]4 ,/ep-d[n trans=m]s4 ,electric furnaces4 ,weld+ by electricity4 ,m]g+ ! p>ticles ( ! jo9$ ends4 ,,xviii4 ,x-,,ray1 ,,radium ,,& ,,! ,,l ,page #ahd ,! cam]a & ! eye4 ,act9ic rays4 ,h]tzian waves4 ,high-t5sion app>atus4 ,vacuum tubes4 ,"* ( ! ultra-violet rays4 ,h[ di/+ui%$4 ,! infra-r$ rays4 ,_! uses4 ,x-rays n capable ( reflection4 ,n subject to refraction4 ,transmission ?r\gh opaque sub/ances4 ,r$uc+ rates ( vibration4 ,radium4 ,radio-activity4 ,radio-active mat]ials4 ,pit*bl5de4 ,a new =m ( en]gy4 ,electrical s\rce4 ,heal+ p[]4 ,problems = sci5ti/s4 ,,li/ ,,( ,,illu/rations ,,fig4 #a4 ,"w b5* ,frontispiece ,,page #b4 ,top ( magnet-w9d+ reel #ad #c4 ,side ( magnet-w9d+ reel #ad #d4 ,j\rnal block #ae #e4 ,pla9 magnet b> #ai #f4 ,sev]$ magnet #bj #g4 ,rev]s$ magnets #ba #h4 ,horse%oe magnet #bb #i4 ,e>?'s magnetic l9es #bc #aj4 ,two p]man5t magnets #bd #aa4 ,magnets 9 e>?'s magnetic field #bd #ab4 ,armatures = magnets #be #ac4 ,magnetiz$ field #bf #ad4 ,magnetiz$ b> #bf #ae4 ,direction ( curr5t #bg #af4 ,direction ( induction curr5t #bh #ag4 ,frictional-electricity ma*9e #cj #ah4 ,leyd5 j> #cb #ai4 ,galvanic electricity4 ,cr[n ( cups #cc #bj4 ,voltaic electricity #cd #ba4 ,prim>y batt]y #cf #bb4 ,dynamo field & pole piece #ci #bc4 ,base & fields assembl$ #da #bd4 ,details ( ! armature1 core #db #be4 ,details ( ! armature1 body #db #bf4 ,armature ,j\rnals #dc #bg4 ,commutator #dc #bh4 ,end view ( armature1 m\nt$ #dd #bi4 ,top view ( armature on base #de #cj4 ,field w9d+ #dg #ca4 ,s]ies-w\nd #dg #cb4 ,%unt-w\nd #dh #cc4 ,comp\nd-w\nd #dh #cd4 ,compass magnet1 sw+ to ! "r #ej #ce4 ,magnetic compass #ej #cf4 ,magnet1 sw+ to ! left #ej #cg4 ,indicat+ direction ( curr5t #ea #ch4 ,! bridge ( ! detector #eb #ci4 ,details ( detector #ec #dj4 ,cross-section ( detector #ed #da4 ,acid voltamet] #ef #db4 ,copp] voltamet] #ef #dc4 ,two-pole swit* #ff #dd4 ,d\ble-pole swit* #ff #de4 ,slid+ swit* #fg #df4 ,rheo/at =m ( swit* #fh #dg4 ,rev]s+ swit* #fi #dh4 ,pu% button #gj #di4 ,electric bell #ga #ej4 ,armature ( electric bell #gb #ea4 ,v]tical section ( annunciator #gb #eb4 ,front view ( annunciator #gb #ec4 ,horizontal section ( annunciator #gb #ed4 ,front plate ( annunciator #gb #ee4 ,al>m swit* on w9d[ #gf #ef4 ,burgl> al>m on w9d[ #gf #eg4 ,burgl> al>m contact #gg #eh4 ,neutral position ( contact #gh #ei4 ,circuit+ = electric bell #gi #fj4 ,annunciators 9 circuit #hj #fa4 ,wir+ sy/em = a h\se #hj #fb4 ,accumulator grids #hc #fc4 ,assemblage ( accumulator grids #he #fd4 ,connect+ up /orage batt]y 9 s]ies #hg #fe4 ,p>allel s]ies #hh #ff4 ,*>g+ circuit #hh #fg4 ,telegraph s5d+ key #ia #fh4 ,telegraph s\nd] #ib #fi4 ,a telegraph circuit #id #gj4 ,induction coil & circuit #ii #ga4 ,illu/rat+ ela/icity #ajj #gb4 ,cond5s] #aja #gc4 ,high-t5sion circuit #ajb #gd4 ,curr5t int]rupt] #ajc #ge4 ,wireless-telegraphy coh]] #aje #gf4 ,wireless s5d+-app>atus #ajg #gg4 ,wireless receiv+-app>atus #ajh #gh4 ,ac\/ic telephone #aaa #gi4 ,illu/rat+ vibrations #aaa #hj4 ,! magnetic field #aab #ha4 ,section ( telephone receiv] #aad #hb4 ,! magnet & receiv] head #aae #hc4 ,simple telephone connection #aaf #hd4 ,telephone /ations 9 circuit #aag #he4 ,illu/rat+ light contact po9ts #aah #hf4 ,! microphone #aai #hg4 ,! transmitt] #aai #hh4 ,complete telephone circuit #aba #hi4 ,device = mak+ hydrog5 & oxyg5 #abd #ij4 ,electric-wat] purifi] #abg #ia4 ,portable electric purifi] #abi #ib4 ,section ( positive plate #acj #ic4 ,section ( negative plate #acj #id4 ,positive & negative 9 position #acj #ie4 ,=m ( ! insulator #acj #if4 ,simple electric heat] #acg #ig4 ,side view ( resi/ance device #aci #ih4 ,top view ( resi/ance device #aci #ii4 ,plan view ( electric iron #adj #ajj4 ,section ( electric iron #ada #aja4 ,!rmo-electric c\ple #adc #ajb4 ,cutt+ a magnetic field #adf #ajc4 ,alt]nations1 fir/ position #adh #ajd4 ,alt]nations1 second position #adh #aje4 ,alt]nations1 ?ird position #adh #ajf4 ,alt]nations1 f\r? position #adh #ajg4 ,increas+ alt]nations1 fir/ view #adi #ajh4 ,increas+ alt]nations1 second view #adi #aji4 ,connection ( alt]nat+ dynamo armature #aej #aaj4 ,direct curr5t dynamo #aea #aaa4 ,circuit wires 9 direct curr5t dynamo #aeb #aab4 ,alt]nat+ pol>ity l9es #aed #aac4 ,alt]nat+ curr5t dynamo #aee #aad4 ,*ok+ coil #aeg #aae4 ,a trans=m] #aeh #aaf4 ,p>allel c>bons #afd #aag4 ,arc-light+ circuit #afe #aah4 ,int]rupt$ conductor #aff #aai4 ,inc&esc5t circuit #afg #abj4 ,magnetic action 9 dynamo1 #a/ #agg #aba4 ,magnetic action 9 dynamo1 #b;d #agg #abb4 ,magnetic action 9 dynamo1 #c;d #agh #abc4 ,magnetic action 9 dynamo1 #d? #agh #abd4 ,magnetic action 9 motor1 #a/ #agi #abe4 ,magnetic action 9 motor1 #b;d #agi #abf4 ,magnetic action 9 motor1 #c;d #ahj #abg4 ,magnetic action 9 motor1 #d? #ahj ,,introductory ,electricity1 l e sci5ce1 pres5ts two phases to ! /ud5t1 "o belong+ to a !oretical k1 & ! o!r :i* p]ta9s to ! practical application ( t k4 ,! boy is directly int]e/$ 9 ! practical use :i* he c make ( ?is wond]ful ph5om5on 9 nature4 ,x is1 9 reality1 ! mo/ successful av5ue by :i* he may obta9 ! !ory1 = he le>ns ! ab/ract m readily f concrete examples4 ,x is an art 9 :i* %op practice is a great] educator ?an c be possible ) books4 ,boys are n1 g5]ally1 incl9$ to speculate or !orize on ph5om5a ap>t f ! "w itself2 b once put !m into contact ) ! me*anism itself1 let !m become a liv+ "p ( x1 & !y w comm5ce to reason & ?9k = !mselves4 ,x w\ld be a dry1 dull & un9t]e/+ ?+ to tell a boy t electricity c be g5]at$ by rivet+ toge!r two pieces ( dissimil> metals1 & apply+ heat to ! juncture4 ,b put into 8 h&s ! metals1 & set him to p]=m ! actual "w ( rivet+ ! metals toge!r1 !n wir+ up ! ends ( ! metals1 heat+ !m1 &1 ) a galvanomet]1 wat*+ = results1 x w at once make him see some?+ 9 ! exp]im5t :i* nev] occurr$ :5 ! ab/ract !ory 0 prop\nd$4 ,he w inquire fir/ :at metals %\ld be us$ to get ! be/ results1 & f9ally1 he w speculate z to ! reasons = ! ph5om5a4 ,:5 he le>ns t all metals are positive-negative or negative-positive to ea* o!r1 he has grasp$ a new idea 9 ! realm ( k1 :i* he unconsci\sly traces back /ill fur!r1 only to le>n t he has ent]$ a field :i* relates to ! con/itution ( matt] itself4 ,z he foll[s ! subject ?r\gh its v>i\s *annels he w le>n t !re is a common s\rce ( all ?+s2 a manife/ation common to all matt]1 & t all sub/ances 9 nature are l9k$ toge!r 9 a mo/ wond]ful way4 ,an impulse mu/ be giv5 to a boy's tra9+4 ,! "t is pa/ = ! rule-&-rote me?od4 ,! rule c be le>n$ bett] by a manual application ?an by committ+ a s5t5ce to memory4 ,9 ! prep>ation ( ?is book1 !re=e1 ,i h made practice & "w ! pr$om9at+ factors4 ,x has be5 my aim to sugge/ ! be/ =m 9 :i* to d ! ?+s 9 a practical way1 & f t "w1 z ! boy c>ries x out1 to d$uce c]ta9 laws & develop ! pr9ciples :i* und]lie !m4 ,:]ev] x is deem$ possible to d s1 x is plann$ to h ! boy make ^! discov]ies = himself1 s z to enc\rage him to become a ?9k] & a reason] in/ead ( a m]e ma*9e4 ,a boy does n develop into a philosoph] or a sci5ti/ ?r\gh be+ told he mu/ le>n ! pr9ciples ( ?is tea*+1 or ! fundam5tals ( t s*ool ( reason+4 ,he w unconsci\sly imbibe ! _s & ! will+ness if we b place be=e him ! tools by :i* he may build ev5 ! simple ma*9]y t displays ! v>i\s electrical manife/ations4 ,,*apt] ,i ,,! ,,/udy ,,( ,,electricity4 ,,hi/orical ,!re is no /udy s pr(\nd z electricity4 ,x is a m>vel to ! sci5ti/ z well z to ! novice4 ,x is simple 9 its manife/ations1 b mo/ complex 9 its organization & 9 its ramifications4 ,x has be5 %[n t light1 heat1 magnetism & electricity are ! same1 b t !y diff] m]ely 9 _! modes ( motion4 ,,fir/ ,,hi/orical ,,acc\nt4--,! fir/ hi/orical acc\nt ( electricity dates back to #fjj ye>s ,b4 ,c4 ,?ales ( ,miletus 0 ! fir/ to describe ! prop]ties ( amb]1 :i*1 :5 rubb$1 attract$ & repell$ light bodies4 ,! anci5ts also describ$ :at 0 probably t\rmal9e1 a m9]al :i* has ! same qualities4 ,! torp$o1 a fi% :i* has ! p[] ( emitt+ electric impulses1 0 kn[n 9 v e>ly times4 ,f t p]iod d[n to ab\t ! ye> #afjj no acc\nts ( any hi/orical value h be5 giv54 ,dr4 ,gilb]t1 ( ,engl&1 made a numb] ( rese>*es at t "t1 pr9cipally ) amb] & o!r mat]ials1 & ,boyle1 9 #afej1 made num]\s exp]im5ts ) frictional electricity4 ,sir ,isaac ,newton also took up ! subject at ab\t ! same p]iod4 ,9 #agje ,hawksbee made num]\s exp]im5ts2 also ,gray1 9 #agbj1 & a ,wel%man1 ,dufay1 at ab\t ! same "t4 ,! ,g]mans1 f #agdj to #aghj1 made _m exp]im5ts4 ,9 #agdj1 at ,leyd51 0 discov]$ ! j> :i* be>s t "n4 ,be=e t "t1 all exp]im5ts began & end$ ) frictional electricity4 ,! fir/ attempt to bottle electricity 0 attempt$ by ,mus*5broeck1 at ,leyd51 :o conceiv$ ! idea t electricity 9 mat]ials might be reta9$ by surr\nd+ !m ) bodies :i* did n conduct ! curr5t4 ,he electrifi$ "s wat] 9 a j>1 & communication hav+ be5 e/abli%$ betwe5 ! wat] & ! prime conductor1 8 assi/ant1 :o 0 hold+ ! bottle1 on try+ to dis5gage ! communicat+ wire1 receiv$ a sudd5 %ock4 ,9 #agdg ,sir ,william ,watson fir$ gunp[d] by an electric sp>k1 &1 lat] on1 a p>ty f ! ,royal ,society1 9 conjunction ) ,watson1 conduct$ a s]ies ( exp]im5ts to det]m9e ! velocity ( ! electric fluid1 z x 0 !n t]m$4 ,b5jam9 ,frankl91 9 #agej1 %[$ t lightn+ 0 electricity1 & lat] on made 8 int]e/+ exp]im5ts ) ! kite & ! key4 ,,discov]+ ,,galvanic ,,electricity4--,! great discov]y ( ,galvani1 9 #agij1 l$ to ! recognition ( a new elem5t 9 electricity1 call$ galvanic or voltaic 7nam$ aft] ! exp]im5t]1 ,volta71 & n[ kn[n to be id5tical ) frictional electricity4 ,9 #ahje ,poisson 0 ! fir/ to analyze electricity2 & :5 ,,oer/$ ( ,cop5hag51 9 #ahbj1 discov]$ ! magnetic action ( electricity1 x (f]$ a great /imulus to ! sci5ce1 & pav$ ! way = inve/igation 9 a new direction4 ,amp]e 0 ! fir/ to develop ! idea t a motor or a dynamo c\ld be made op]ative by means ( ! electro-magnetic curr5t2 & ,f>aday1 ab\t #ahcj1 discov]$ electro-magnetic rotation4 ,,electro-,,magnetic ,,=ce4--,f ?is "t on ! k ( electricity grew ) amaz+ rapidity4 ,ohm's def9ition ( electro-motive =ce1 curr5t /r5g? & resi/ance ev5tuat$ into ,ohm's law4 ,?omson greatly simplifi$ ! galvanomet]1 & ,:eat/one inv5t$ ! rheo/at1 a means ( measur+ resi/ance1 ab\t #ahej4 ,!n prim>y batt]ies 7 br\ght =w>d by ,daniels1 ,grove1 ,buns5 & ,?omson1 & electrolysis by ,f>aday4 ,!n came ! in/rum5ts ( precision--! electromet]1 ! resi/ance bridge1 ! ammet]1 ! voltmet]--all ( ! utmo/ value 9 ! sci5ce4 ,,measur+ ,,in/rum5ts4--,! p]fection ( measur+ in/rum5ts did m to advance electricity ?an almo/ any o!r field ( endeavor2 s t aft] #ahge ! inv5tors took up ! subject1 & by _! en]gy develop$ & put into practical op]ation a mo/ wond]ful array ( me*anism1 :i* has become valuable 9 ! s]vice ( man 9 almo/ e field ( human activity4 ,,rapidity ,,( ,,mod]n ,,progress4--,?is brief hi/ory is giv5 m]ely to %[ :at wond]s h be5 accompli%$ 9 a few ye>s4 ,! art is really less ?an fifty ye>s old1 & yet s rapidly has x gone =w>d t x is n at all surpris+ to he> ! rem>k1 t ! end ( ! wond]s has be5 rea*$4 ,less ?an tw5ty-five ye>s ago a high (ficial ( ! ,unit$ ,/ates ,pat5t ,(fice /at$ t x 0 probable ! end ( electrical rese>* _h be5 rea*$4 ,! mo/ wond]ful developm5ts h be5 made s9ce t "t2 & n[1 z 9 ! pa/1 "o discov]y is b ! prelude to ano!r /ill m rem>kable4 ,we are beg9n+ to le>n t we are only on ! ?re%old ( t /oreh\se 9 :i* nature has lock$ h] secrets1 & t !re is no limit to human +5uity4 ,,h[ ,,to ,,acquire ,,! ,,va/ ,,k4--,z ! boy1 ) 8 limit$ vision1 surveys ?is va/ accumulation ( tools1 in/rum5ts & ma*9]y1 & sees :at has be5 & is n[ be+ accompli%$1 x is n to be wond]$ at t he %\ld ent] ! field ) timidity4 ,9 8 m9d ! great "q is1 h[ to acquire ! k4 ,!re is s mu* to le>n4 ,h[ c x be accompli%$8 ,! answ] to ?is is1 t ! /ud5t ( to-day has ! advantage ( ! k ( all :o h gone be=e2 & n[ ! p]t95t ?+ is to acquire t k4 ,,! ,,means ,,employ$4--,?is br+s u def9itely d[n to an exam9ation ( ! means t we %all employ to in/il ?is k1 s t x may become a p]man5t asset to ! /ud5t's /ore ( in=mation4 ,! mo/ significant ?+ 9 ! hi/ory ( electrical developm5t is ! k t ( all ! great sci5ti/s n "o ( !m ev] add$ any k to ! sci5ce on purely speculative reason+4 ,all ( !m 7 exp]im5t]s4 ,!y practically appli$ & develop$ _! !ories 9 ! laboratory or ! work%op4 ,! natural inf]5ce is1 !re=e1 t ! boy :o />ts out to acquire a k ( electricity1 mu/ n only !orize1 b t he %all1 prim>ily1 conduct ! exp]im5ts1 & !reby acquire ! in=mation 9 a practical way1 "o example ( :i* w make a m la/+ impression ?an pages ( dry text4 ,?r\gh\t ^! pages1 !re=e1 ,i %all1 z briefly z possible1 po9t out ! !ories involv$1 z a f\ndation = ! "w1 & !n illu/rate ! /ructural types or samples2 & ! "w is s arrang$ t :at is done to-day is m]ely a prelude or /epp+-/one to ! next phase ( ! art4 ,9 reality1 we %all travel1 to a consid]able ext5t1 ! c\rse :i* ! great inve/igators foll[$ :5 !y 7 grop+ = ! facts & discov]+ ! great manife/ations 9 nature4 ,,*apt] ,,ii ,,:at ,,tools ,,& ,,app>atus ,,are ,,ne$$ ,,prep>+ ,,! ,,work%op4--,be=e comm5c+ actual exp]im5ts we %\ld prep>e ! work%op & tools4 ,s9ce we are go+ into ?is "w z pione]s1 we %all h to be dep5d5t ^u our own ef=ts = ! production ( ! electrical app>atus1 s z to be able1 ) our home-made factory1 to provide ! p[]1 ! heat & ! electricity4 ,!n1 f9d+ we are successful 9 ^! ent]prises1 we may look =w>d = m worlds to conqu]4 ,by ?is "t our neighbors w become int]e/$ 9 & solicit "w f u4 ,,uses ,,( ,,our ,,work%ops4--,!y may want u to te/ batt]ies1 & x !n becomes necess>y to con/ruct me*anism to detect & measure electricity2 to in/all new & improv$ app>atus2 & to put 9 & connect up electric bells 9 _! h\ses1 z well z burgl> al>ms4 ,to meet ! requirem5ts1 we put 9 a telegraph l9e1 hav+ le>n$1 z well z we are able1 h[ !y are made & op]at$4 ,b we f9d ! telegraph too sl[ & altoge!r unsuit$ = our purposes1 z well z = ! uses ( ! neighborhood1 s we conclude to put 9 a telephone sy/em4 ,,:at ,,to ,,build4--,x is necess>y1 !re=e1 to comm5ce "r at ! bottom to build a telephone1 a transmitt]1 a receiv] & a swit*-bo>d = our sy/em4 ,f ! telephone we soon see ! desirability ( gett+ into t\* ) ! great outside _w1 & wireless telegraphy absorbs our "t & en]gies4 ,b z we le>n m & m ( ! wond]ful ?+s electricity w d1 we are br\ght into contact ) problems :i* directly int]e/ ! home4 ,sanitation attracts our att5tion4 ,:y _c electricity act z an ag5t to purify our dr9k+ wat]1 to /]ilize sewage & to arre/ (f5sive odors8 ,we mu/1 !re=e1 le>n some?+ ab\t ! subject ( electrolysis4 ,,:at ,,to ,,le>n4--,! decomposition ( wat] is n ! only ?+ t we %all describe p]ta9+ to ?is subject4 ,we g a /ep fur!r1 & f9d t we c decompose metals z well z liquids1 & t we c make a pure metal out ( an impure "o1 z well z make ! f\le/ wat] pure4 ,b we %all also1 9 ! c\rse ( our exp]im5ts1 f9d t a *eap metal c be coat$ ) a co/ly "o by means ( electricity--t we c electroplate by electrolysis4 ,,uses ,,( ,,! ,,electrical ,,devices4--,:ile all ?is is progress+ & our factory is turn+ out an amaz+ v>iety ( useful articles1 we are l$ to inquire into ! uses to :i* we may devote our surplus electricity4 ,! curr5t may be div]t$ = boil+ wat]2 = weld+ metals2 = heat+ sad-irons1 z well z = o!r purposes :i* are daily requir$4 ,,tools4--,to d ^! ?+s tools are necess>y1 & = ! pres5t !y %\ld n be exp5sive4 ,a small1 rigidly built b5* is ! fir/ requirem5t4 ,?is may be made1 z %[n 9 ,fig4 #a1 ( ?ree #b-;in* planks1 ea* #aj in*es wide & #f feet long1 m\nt$ on legs #cf in*es 9 height4 ,9 ! front "p are ?ree draw]s = y\r mat]ial1 or ! small odds & ends1 z well z = su* little tools z y may accumulate4 ,!n y w ne$ a small vise1 say1 ) a #b-;in* jaw1 & y w also require a h& reel = w9d+ magnets4 ,?is w be fully describ$ h]eaft]4 ,y c also1 probably1 get a small1 *eap anvil1 :i* w be ( ! greate/ s]vice 9 y\r "w4 ,x %\ld be m\nt$ close up to ! "w b5*4 ,two small hamm]s1 "o ) an ,a-%ap$ peon1 & ! o!r ) a r\nd peon1 %\ld be select$1 & also a plane & a small wood saw ) f9e tee?4 ,a bit /ock1 or a rat*et drill1 if y c af=d x1 ) a v>iety ( small drills2 two wood *isels1 say ( #c_/h-;in* & #c_/d-;in* wid?s2 small cold *isels2 hack saw1 #aj-;in* blade2 small iron squ>e2 pair ( divid]s2 t9 %e>s2 wire cutt]s2 #b pairs ( pli]s1 "o flat & ! o!r r\nd-nos$2 #b awls1 c5t]+ pun*1 wire cutt]s1 &1 f9ally1 sold]+ tools4 ,illu/ration3 ,fig4 #b4 ,top ,view ,,magnet-,,w9d+ ,,reel ,illu/ration3 ,fig4 #c4 ,side ,view ,,magnet-,,w9d+ ,,reel ,if a gas /ove is n available1 a braz+ tor* is an ess5tial tool4 ,num]\s small tor*es are be+ made1 :i* are *eap & easily op]at$4 ,a small sold]+ iron1 ) po9t$ end1 %\ld be provid$2 also metal %e>s & a small squ>e2 an awl & sev]al sizes ( gimlets2 a screwdriv]2 pair ( pli]s & wire cutt]s4 ,f ! =ego+ x w be se5 t ! co/ ( tools is n a v exp5sive item4 ,?is entire outfit1 n includ+ ! anvil & vise1 may be pur*as$ new = ab\t #bj4jj1 s we h n be5 extravagant4 ,,magnet-,,w9d+ ,,reel4--,"s little prep>ation mu/ be made1 s we may be enabl$ to h&le our "w by ! con/ruction ( me*anical aids4 ,illu/ration3 ,fig4 #d4 ,j\rnal ,block4 ,fir/ ( ^! is ! magnet-w9d+ reel1 a plan view ( :i* is %[n 9 ,fig4 #b4 ,?is1 = our pres5t "w1 w be made :olly ( wood4 ,select a plank #a-a_/b in*es ?ick & #h in*es wide1 & f ?is cut (f two pieces 7,a71 ea* #g in*es long1 & !n trim (f ! corn]s 7,b1 ,b71 z %[n 9 ,fig4 #d4 ,to s]ve z ! m&rel 7,c1 ,fig4 #b71 select a piece ( broom/ick #i in*es long4 ,bore a hole 7,d7 9 ea* block 7,a7 a half in* bel[ ! upp] m>g9 ( ! block1 ?is hole be+ ( su* diamet] t ! broom/ick m&rel w fit & easily turn !re94 ,place a crank 7,e71 #e in*es long1 on ! out] end ( ! m&rel1 z 9 ,fig4 #c4 ,!n m\nt "o block on ! end ( ! b5* & ! o!r block #c in*es away4 ,affix !m to ! b5* by nails or screws1 pref]ably ! latt]4 ,on ! inn] end ( ! m&rel put a block 7,f7 ( h>d wood4 ,?is is done by bor+ a hole #a in* deep 9 ! c5t] ( ! block1 into :i* ! m&rel is driv54 ,on ! out] face ( ! block is a squ>e hole l>ge en\gh to receive ! head ( a #c_/h-;in* bolt1 & into ! depression ?us =m$ a screw 7,g7 is driv5 ?r\gh ! block & into ! end ( ! m&rel1 s z to hold ! block 7,f7 & m&rel firmly toge!r4 ,:5 ^! p>ts are prop]ly put toge!r1 ! inn] side ( ! block w re/ & turn aga9/ ! inn] j\rnal block 7,a74 ,! tailpiece is made ( a #b #d scantl+ 7,h71 #aj in*es long1 "o end ( x be+ nail$ to a transv]se block 7,i7 #b #b #d4 ,! inn] face ( ?is block has a depression 9 :i* is plac$ a ,v-%ap$ cup 7,j71 to receive ! end ( ! magnet core 7,k7 or bolt1 :i* is to be us$ = ?is purpose4 ,! tailpiece 7,h7 has a longitud9al slot 7,l7 #e in*es long adapt$ to receive a #a_/b-;in* bolt 7,m71 :i* passes d[n ?r\gh ! b5*1 & is1 !re=e1 adju/able1 s x may be mov$ to & f ! j\rnal be>+ 7,a71 !reby provid+ a place = ! bolts to be put 94 ,^! bolts are ! magnet cores 7,k71 #f in*es long1 b !y may be ev5 long]1 if y bore sev]al holes 7,n7 ?r\gh ! b5* s y may set ov] ! tailpiece4 ,) a s+le tool made sub/antially l ?is1 ov] a ?\s& ( ! f9e/ magnets h be5 w\nd4 ,its value w be appreciat$ aft] y h _h ! exp]i5ce ( w9d+ a few magnets4 ,,ord] ,,9 ,,! ,,work%op4--,select a place = ea* tool on ! re> upright ( ! b5*1 & make x a rule to put ea* tool back into its place aft] us+4 ,?is1 if p]si/$ 91 w soon become a habit1 & w save y h\rs ( "t4 ,hunt+ = tools is ! unpr(itable "p ( any "w4 ,,*apt] ,,iii ,,magnets1 ,,coils1 ,,armatures1 ,,etc4 ,,! ,,two ,,k9ds ,,( ,,magnet4--,g5]ally speak+1 magnets are ( two k9ds1 namely1 p]man5t & electro-magnetic4 ,,p]man5t ,,magnets4--,a p]man5t magnet is a piece ( /eel 9 :i* an electric =ce is ex]t$ at all times4 ,an electro-magnet is a piece ( iron :i* is magnetiz$ by a w9d+ ( wire1 & ! magnet is en]giz$ only :ile a curr5t ( electricity is pass+ ?r\gh ! wire4 ,,electro-,,magnet4--,! electro-magnet1 !re=e1 is ! m useful1 because ! pull ( ! magnet c be controll$ by ! curr5t :i* actuates x4 ,! electro-magnet is ! mo/ ess5tial ( all contrivances 9 ! op]ation & use ( electricity4 ,x is ! piece ( me*anism :i* does ! physical "w ( almo/ e electrical app>atus or ma*9e4 ,x is ! device :i* has ! p[] to conv]t ! unse5 electric curr5t into motion :i* may be obs]v$ by ! human eye4 ,)\t x electricity w\ld be a useless ag5t to man4 ,:ile ! electro-magnet is1 !re=e1 ! =m ( device :i* is almo/ :olly us$1 x is necess>y1 fir/1 to und]/& ! pr9ciples ( ! p]man5t magnet4 ,,magnetism4--,! curi\s =ce ex]t$ by a magnet is call$ magnetism1 b its orig9 has nev] be5 expla9$4 ,we "k its manife/ations only1 & laws h be5 =mulat$ to expla9 its v>i\s phases2 h[ to make x m or less int5se2 h[ to make its pull m effective2 ! %ape & =m ( ! magnet & ! mat]ial mo/ useful 9 its con/ruction4 ,illu/ration3 ,fig #e4 ,,pla9 ,,magnet ,,b> ,,mat]ials ,,= ,,magnets4--,iron & /eel are ! be/ mat]ials = magnets4 ,"s metals are non-magnetic1 ?is apply+ to iron if comb9$ ) manganese4 ,o!rs1 l sulphur1 z9c1 bismu?1 antimony1 gold1 silv] & copp]1 n only are non-magnetic1 b !y are actually repell$ by magnetism4 ,!y are call$ ! diamagnetics4 ,,non-,,magnetic ,,mat]ials4--,any non-magnetic body 9 ! pa? ( a magnetic =ce does n scre5 or dim9i% its action1 :]eas a magnetic sub/ance w4 ,9 ,fig4 #e we %[ ! simple/ =m ( magnet1 m]ely a b> ( /eel 7,a7 ) ! magnetic l9es ( =ce pass+ f end to end4 ,x w be und]/ood t ^! l9es ext5d out on all sides1 & n only along two sides1 z %[n 9 ! draw+4 ,! object is to expla9 cle>ly h[ ! l9es run4 ,illu/ration3 ,fig4 #f4 ,,sev]$ ,,magnet ,,action ,,( ,a ,,sev]$ ,,magnet4--,n[1 let u suppose t we sev] ?is b> 9 ! middle1 z 9 ,fig4 #f1 or at any o!r po9t betwe5 ! ends4 ,9 ?is case ea* "p becomes a p]fect magnet1 & a new nor? pole 7,n7 & a new s\? pole 7,s7 are made1 s t ! movem5t ( ! magnetic l9es ( =ce are /ill 9 ! same direction 9 ea*--t is1 ! curr5t fl[s f ! nor? pole to ! s\? pole4 ,,:at ,,nor? ,,& ,,s\? ,,poles ,,mean4--,if ^! two p>ts are plac$ close toge!r !y w attract ea* o!r4 ,b if1 on ! o!r h&1 "o ( ! pieces is rev]s$1 z 9 ,fig4 #g1 !y w repel ea* o!r4 ,f ?is comes ! /atem5t t likes repel & unlikes attract ea* o!r4 ,,repulsion ,,& ,,attraction4--,?is physical act ( repulsion & attraction is made use ( 9 motors1 z we %all see h]e9aft]4 ,x w be well to be> 9 m9d t 9 treat+ ( electricity ! nor? pole is always associat$ ) ! plus sign 77 & ! s\? pole ) ! m9us sign 7-74 ,or ! ,n sign is positive & ! ,s sign negative electricity4 ,illu/ration3 ,fig4 #g4 ,,rev]s$ ,,magnets ,,positives ,,& ,,negatives4--,!re is really no diff]5ce betwe5 positive & negative electricity1 s call$1 b ! =ego+ me?od m]ely s]ves z a means ( id5tify+ or classify+ ! opposite ends ( a magnet or ( a wire4 ,,magnetic ,,l9es ,,( ,,=ce4--,x w be notic$ t ! magnetic l9es ( =ce pass ?r\gh ! b> & !n g f end to end ?r\gh ! atmosph]e4 ,air is a poor conductor ( electricity1 s t if we c f9d a %ort] way to conduct ! curr5t f ! nor? pole to ! s\? pole1 ! effici5cy ( ! magnet is increas$4 ,?is is accompli%$ by means ( ! well-kn[n horse%oe magnet1 :]e ! two ends 7,n1 ,s7 are br\ght close toge!r1 z 9 ,fig4 #h4 ,,! ,,e>? ,,z ,a ,,magnet4--,! e>? is a huge magnet & ! magnetic l9es run f ! nor? pole to ! s\? pole ar\nd all sides ( ! globe4 ,illu/ration3 ,fig4 #h4 ,,horse%oe ,,magnet ,! nor? magnetic pole does n co9cide ) ! true nor? pole or ! pivotal po9t ( ! e>?'s rotation1 b x is suffici5tly ne> = all practical purposes4 ,fig4 #i %[s ! magnetic l9es runn+ f ! nor? to ! s\? pole4 ,,:y ,,! ,,compass ,,po9ts ,,nor? ,,& ,,s\?4--,n[1 let u try to asc]ta9 :y ! compass po9ts nor? & s\?4 ,let u assume t we h a l>ge magnet 7,a1 ,fig4 #aj71 & susp5d a small magnet 7,b7 above x1 s t x is )9 ! magnetic field ( ! l>ge magnet4 ,?is may be done by means ( a %ort p9 7,c71 :i* is locat$ 9 ! middle ( ! magnet 7,b71 ! upp] end ( ?is p9 hav+ !reon a loop to :i* a ?read 7,d7 is atta*$4 ,! p9 also c>ries !reon a po9t] 7,e71 :i* is direct$ t[>d ! nor? pole ( ! b> 7,b74 ,illu/ration3 ,fig4 #i4 ,,e>?',s ,,magnetic ,,l9es ,y w n[ take note ( ! int]ior magnetic l9es 7,x71 & ! ext]ior magnetic l9es 7,z7 ( ! l>ge magnet 7,a71 & comp>e ! direction ( _! fl[ ) ! simil> l9es 9 ! small magnet 7,b74 ,! small magnet has bo? its ext]ior & its int]ior l9es )9 ! ext]ior l9es 7,z7 ( ! l>ge magnet 7,a71 s t z ! small magnet 7,b7 is capable ( sw++ ar\nd1 ! ,n pole ( ! b> 7,b7 w po9t t[>d ! ,s pole ( ! l>g] b> 7,a74 ,! small b>1 !re=e1 is influ5c$ by ! ext]ior magnetic field 7,z74 ,illu/ration3 ,fig4 #aj4 ,,two ,,p]man5t ,,magnets ,illu/ration3 ,fig4 #aa4 ,,magnets ,,9 ,,! ,,e>?',s ,,magnetic ,,field ,let u n[ take ! outl9e repres5t$ by ! e>?'s surface 7,fig4 #aa71 & susp5d a magnet 7,a7 at any po9t1 l ! ne$le ( a compass1 & x w be se5 t ! ne$le w arrange itself nor? & s\?1 )9 ! magnetic field :i* fl[s f ! nor? to ! s\? pole4 ,,peculi>ity ,,( ,a ,,magnet4--,"o *>act]i/ic ( a magnet is t1 :ile app>5tly ! magnetic field fl[s out at "o end ( ! magnet1 & moves inw>dly at ! o!r end1 ! p[] ( attraction is j ! same at bo? ends4 ,9 ,fig4 #ab are %[n a b> 7,a7 & a horse%oe magnet 7,b74 ,! b> 7,a7 has metal blocks 7,c7 at ea* end1 & ea* ( ^! blocks is attract$ to & held 9 contact ) ! ends by magnetic influ5ce1 j ! same z ! b> 7,d7 is attract$ by & held aga9/ ! two ends ( ! horse%oe magnet4 ,^! blocks 7,c7 or ! b> 7,d7 are call$ armatures4 ,?r\gh !m is repres5t$ ! visible motion produc$ by ! magnetic field4 ,illu/ration3 ,fig4 #ab4 ,,armatures ,,= ,,magnets ,,action ,,( ,,! ,,electro-,,magnet4--,! electro-magnet ex]ts its =ce 9 ! same mann] z a p]man5t magnet1 s f> z attraction & repulsion are conc]n$1 & x has a nor? & a s\? pole1 z 9 ! case ) ! p]man5t magnet4 ,an electro-magnet is simply a b> ( iron ) a coil or coils ( wire ar\nd x2 :5 a curr5t ( electricity fl[s ?r\gh ! wire1 ! b> is magnetiz$4 ,! mom5t ! curr5t is cut (f1 ! b> is demagnetiz$4 ,! "q t n[ arises is1 :y an electric curr5t fl[+ ?r\gh a wire1 "u ^? conditions1 magnetizes ! b>1 or core1 z x is call$4 ,illu/ration3 ,fig4 #ac4 ,,magnetiz$ ,,field ,illu/ration3 ,fig4 #ad4 ,,magnetiz$ ,,b> ,9 ,fig4 #ac is %[n a piece ( wire 7,a74 ,let u assume t a curr5t ( electricity is fl[+ ?r\gh ?is wire 9 ! direction ( ! d>ts4 ,:at actually takes place is t ! electricity ext5ds out beyond ! surface ( ! wire 9 ! =m ( ! clos$ r+s 7,b74 ,if1 n[1 ?is wire 7,a7 is w\nd ar\nd an iron core 7,c1 ,fig4 #ad71 y w obs]ve t ?is electric field1 z x is call$1 entirely surr\nds ! core1 or r1 t ! core is )9 ! magnetic field or influ5ce ( ! curr5t fl[+ ?r\gh ! wire1 & ! core 7,c7 !reby becomes magnetiz$1 b x is magnetiz$ only :5 ! curr5t passes ?r\gh ! wire coil 7,a74 ,illu/ration3 ,fig4 #ae4 ,,direction ,,( ,,curr5t ,f ! =ego+1 x w be und]/ood t a wire c>ry+ a curr5t ( electricity n only is affect$ )9 its body1 b t x also has a sph]e ( influ5ce ext]iorly to ! body ( ! wire1 at all po9ts2 & advantage is tak5 ( ?is ph5om5on 9 con/ruct+ motors1 dynamos1 electrical measur+ devices & almo/ e k9d ( electrical me*anism 9 exi/5ce4 ,,ext]ior ,,magnetic ,,influ5ce ,,ar\nd ,a ,,wire ,,c>ry+ ,a ,,curr5t4--,be> 9 m9d t ! wire coil 7,a1 ,fig4 #ad7 does n come into contact ) ! core 7,c74 ,x is insulat$ f ! core1 ei!r by air or by rubb] or o!r insulat+ sub/ance1 & a curr5t pass+ f ,a to ,c "u ^? conditions is a curr5t ( induction4 ,on ! o!r h&1 ! curr5t fl[+ ?r\gh ! wire 7,a7 f end to end is call$ a conduction curr5t4 ,rememb] ^! t]ms4 ,9 ?is connection !re is also ano!r ?+ :i* y w d well to be> 9 m9d4 ,9 ,fig4 #ae y w notice a core 7,c7 & an insulat$ wire coil 7,b7 w\nd ar\nd x4 ,! curr5t1 ?r\gh ! wire 7,b71 z %[n by ! d>ts 7,d71 moves 9 "o direction1 & ! induc$ curr5t 9 ! core 7,c7 travels 9 ! opposite direction1 z %[n by ! d>ts 7,d74 ,illu/ration3 ,fig4 #af4 ,,direction ,,( ,,induction ,,curr5t ,,p>allel ,,wires4--,9 l mann]1 if two wires 7,a1 ,b1 ,fig4 #af7 are p>allel ) ea* o!r1 & a curr5t ( electricity passes along ! wire 7,a7 9 "o direction1 ! induc$ curr5t 9 ! wire 7,b7 w move 9 ! opposite direction4 ,^! fundam5tal pr9ciples %\ld be ?or\ghly und]/ood & ma/]$4 ,,*apt] ,,iv ,,frictional1 ,,voltaic ,,or ,,galvanic1 ,,& ,,electro-,,magnetic ,,electricity ,,?ree ,,electrical ,,s\rces4--,x has be5 f\nd t !re are ?ree k9ds ( electricity1 or1 to be m accurate1 !re are ?ree ways to g5]ate x4 ,^! w n[ be describ$4 ,:5 man fir/ began exp]im5t+1 he produc$ a curr5t by frictional means1 & collect$ ! electricity 9 a bottle or j>4 ,electricity1 s /or$1 c\ld be drawn f ! j>1 by atta*+ !reto suitable connection4 ,?is c\ld be effect$ only 9 "o way1 & t 0 by dis*>g+ ! entire accumulation in/antane\sly4 ,at t "t !y knew ( no means :]eby ! curr5t c\ld be made to fl[ f ! j> z f a batt]y or cell4 ,,frictional ,,electricity4--,) a view ( expla9+ ! pr9ciples involv$1 we %[ 9 ,fig4 #ag a ma*9e = produc+ electricity by friction4 ,illu/ration3 ,fig4 #ag4 ,,friction-,,electricity ,,ma*9e ,?is is made up z foll[s3 ,a repres5ts ! base1 hav+ !reon a flat memb] 7,b71 on :i* is m\nt$ a pair ( p>allel po/s or /&>ds 7,c1 ,c71 :i* are connect$ at ! top by a cross piece 7,d74 ,betwe5 ^! two po/s is a glass disc 7,e71 m\nt$ ^u a %aft 7,f71 :i* passes ?r\gh ! po/s1 ?is %aft hav+ at "o end a crank 7,g74 ,two lea!r collect+ surfaces 7,h1 ,h71 :i* are 9 contact ) ! glass disc 7,e71 are held 9 position by arms 7,i1 ,j71 ! arm 7,i7 be+ support$ by ! cross piece 7,d71 & ! arm 7,j7 held by ! base piece 7,b74 ,a rod 7,k71 ,u-%ap$ 9 =m1 passes ov] ! /ructure "h ?us describ$1 its ends be+ secur$ to ! base 7,b74 ,! arms 7,i1 ,j7 are bo? electrically connect$ ) ?is rod1 or conductor 7,k71 jo9$ to a ma9 conductor 7,l71 :i* has a t]m9at+ knob 7,m74 ,on ea* side & close to ! t]m9al end ( ea* lea!r collector 7,h7 is a =k-%ap$ collector 7,n74 ,^! two collectors are also connect$ electrically ) ! conductor 7,k74 ,:5 ! disc is turn$ electricity is g5]at$ by ! lea!r flaps & accumulat$ by ! collectors 7,n71 aft] :i* x is ready to be dis*>g$ at ! knob 7,m74 ,9 ord] to collect ! electricity ?us g5]at$ a vessel call$ a ,leyd5 j> is us$4 ,,leyd5 ,,j>4--,?is is %[n 9 ,fig4 #ah4 ,! j> 7,a7 is ( glass coat$ ext]iorly at its l[] end ) t9foil 7,b71 :i* ext5ds up a little m ?an halfway f ! bottom4 ,?is j> has a wood5 cov] or top 7,c71 provid$ c5trally ) a hole 7,d74 ,! j> is design$ to receive )9 x a tripod & /&>d 7,e7 ( lead4 ,)9 ?is lead /&>d is fitt$ a metal rod 7,f71 :i* projects upw>dly ?r\gh ! hole 7,d71 its upp] end hav+ !reon a t]m9al knob 7,g74 ,a slid+ cork 7,h7 on ! rod 7,f7 s]ves z a means to close ! j> :5 n 9 use4 ,:5 9 use ?is cork is rais$ s ! rod may n come into contact1 electrically1 ) ! cov] 7,c74 ,! j> is half fill$ ) sulphuric acid 7,i71 aft] :i*1 9 ord] to *>ge ! j>1 ! knob 7,g7 is br\ght into contact ) ! knob 7,m7 ( ! friction g5]ator 7,fig4 #ag74 ,,voltaic ,,or ,,galvanic ,,electricity4--,! second me?od ( g5]at+ electricity is by *emical means1 s call$1 because a liquid is us$ z "o ( ! ag5ts4 ,illu/ration3 ,fig4 #ah4 ,,leyd5 ,,j> ,galvani1 9 #agij1 made ! exp]im5ts :i* l$ to ! g5]ation ( electricity by means ( liquids & metals4 ,! fir/ batt]y 0 call$ ! cr[n ( cups1 %[n 9 ,fig4 #ai1 & consi/+ ( a r[ ( glass cups 7,a71 conta9+ salt wat]4 ,^! cups 7 electrically connect$ by means ( b5t metal /rips 7,b71 ea* /rip hav+ at "o end a copp] plate 7,c71 & at ! o!r end a z9c plate 7,d74 ,! fir/ plate 9 ! cup at "o end is connect$ ) ! la/ plate 9 ! cup at ! o!r end by a conductor 7,e7 to make a complete circuit4 ,illu/ration3 ,fig4 #ai4 ,,galvanic ,,electricity4 ,,cr[n ,,( ,,cups ,,! ,,cell ,,& ,,batt]y4--,f ! =ego+ x w be se5 t )9 ea* cup ! curr5t fl[s f ! z9c to ! copp] plates1 & ext]iorly f ! copp] to ! z9c plates ?r\gh ! conductors 7,b & ,e74 ,a few ye>s aft]w>ds ,volta devis$ :at is kn[n z ! voltaic pile 7,fig4 #bj74 ,,voltaic ,,pile--,,h[ ,,made4--,?is is made ( alt]nate discs ( copp] & z9c ) a piece ( c>dbo>d ( correspond+ size betwe5 ea* z9c & copp] plate4 ,! c>dbo>d discs are moi/5$ ) acidulat$ wat]4 ,! bottom disc ( copp] has a /rip :i* connects ) a cup ( acid1 & "o wire t]m9al 7,a7 runs !refrom4 ,! upp] disc1 :i* is ( z9c1 is also connect$1 by a /rip1 ) a cup ( acid f :i* ext5ds ! o!r t]m9al wire 7,b74 ,illu/ration3 ,fig4 #bj4 ,,voltaic ,,electricity ,plus & ,m9us ,signs4--,x w be not$ t ! positive or copp] disc has ! plus sign 77 :ile ! z9c disc has ! m9us 7-7 sign4 ,^! signs d5ote ! positive & ! negative sides ( ! curr5t4 ,! liquid 9 ! cells1 or 9 ! moi/5$ pap]1 is call$ ! electrolyte & ! plates or discs are call$ electrodes4 ,to def9e !m m cle>ly1 ! positive plate is ! anode1 & ! negative plate ! ca?ode4 ,! curr5t1 ^u ent]+ ! z9c plate1 decomposes ! wat] 9 ! electrolyte1 !reby =m+ oxyg54 ,! hydrog5 9 ! wat]1 :i* has also be5 =m$ by ! decomposition1 is c>ri$ to ! copp] plate1 s t ! plate f9ally is s coat$ ) hydrog5 t x is difficult = ! curr5t to pass ?r\gh4 ,?is condition is call$ pol>ization1 & to prev5t x has be5 ! aim ( all inv5tors4 ,to x also we may attribute ! great v>iety ( prim>y batt]ies1 ea* hav+ "s di/9ctive claim ( m]it4 ,,! ,,common ,,prim>y ,,cell4--,! mo/ common =m ( prim>y cell conta9s sulphuric acid1 or a sulphuric acid solution1 z ! electrolyte1 ) z9c = ! anode1 & c>bon1 in/ead ( copp]1 = ! ca?ode4 ,! ends ( ! z9c & copp] plates are call$ t]m9als1 & :ile ! z9c is ! anode or positive elem5t1 its t]m9al is designat$ z ! positive pole4 ,9 l mann]1 ! c>bon is ! negative elem5t or ca?ode1 & its t]m9al is designat$ z negative pole4 ,fig4 #ba w %[ ! relative arrangem5t ( ! p>ts4 ,x is cu/om>y to t]m t end or elem5t f :i* ! curr5t fl[s z positive4 ,a cell is reg>d$ z a :ole1 & z ! curr5t passes out ( ! cell f ! copp] elem5t1 ! copp] t]m9al becomes positive4 ,illu/ration3 ,fig4 #ba4 ,,prim>y ,,batt]y ,,batt]y ,,resi/ance1 ,,electrolyte ,,& ,,curr5t4--,! foll[+ %\ld be c>efully memoriz$3 ,a cell has ref]5ce to a s+le vessel4 ,:5 two or m cells are c\pl$ toge!r !y =m a batt]y4 ,resi/ance is opposition to ! movem5t ( ! curr5t4 ,if x is (f]$ by ! electrolyte1 x is designat$ ,int]nal ,resi/ance4 ,if1 on ! o!r h&1 ! opposition takes place1 = in/ance1 ?r\gh ! wire1 x is !n call$ ,ext]nal ,resi/ance4 ,! electrolyte mu/ be ei!r acid1 or alkal9e1 or sal9e1 & ! electrodes mu/ be ( dissimil> metals1 s ! electrolyte w attack "o ( !m4 ,! curr5t is measur$ 9 amp]es1 & ! =ce ) :i* x is caus$ to fl[ is measur$ 9 volts4 ,9 practice ! ^w curr5t is us$ to designate amp]e fl[2 & electromotive =ce1 or ,e4 ,m4 ,f41 is us$ in/ead ( voltage4 ,,electro-,,magnetic ,,electricity4--,! ?ird me?od ( g5]at+ electricity is by electro-magnets4 ,! value & use ( induction w n[ be se51 & y w be enabl$ to utilize ! lesson conc]n+ magnetic action ref]r$ to 9 ! previ\s *apt]4 ,,magnetic ,,radiation4--,y w rememb] t e piece ( metal :i* is )9 ! pa? ( an electric curr5t has a space all ab\t its surface f end to end :i* is electrifi$4 ,?is electrifi$ field ext5ds out a c]ta9 di/ance f ! metal1 & is suppos$ to ma9ta9 a movem5t ar\nd x4 ,if1 n[1 ano!r piece ( metal is br\ght )9 range ( ?is electric or magnetic zone & mov$ across x1 s z to cut ?r\gh ?is field1 a curr5t w be g5]at$ !reby1 or r add$ to ! curr5t already ex]t$1 s t if we />t ) a feeble curr5t1 x c be increas$ by rapidly cutt+ ! l9es ( =ce1 z x is call$4 ,,diff]5t ,,k9ds ,,( ,,dynamo4--,:ile !re are _m k9ds ( dynamo1 !y all1 )\t exception1 are con/ruct$ 9 accordance ) ?is pr9ciple4 ,!re are also _m v>ieties ( curr5t4 ,= in/ance1 a dynamo may be made to produce a high voltage & a l[ amp]age2 ano!r ) high amp]age & l[ voltage2 ano!r :i* gives a direct curr5t = light+1 heat+1 p[]1 & electroplat+2 /ill ano!r :i* g5]ates an alt]nat+ curr5t = high t5sion p[]1 or transmission1 arc-light+1 etc41 all ( :i* w be expla9$ h]eaft]4 ,9 ?is place1 h[ev]1 a full description ( a direct-curr5t dynamo w expla9 ! pr9ciple involv$ 9 all dynamos--t to g5]ate a curr5t ( electricity makes x necess>y = u to move a field ( =ce1 l an armature1 rapidly & cont9u\sly ?r\gh ano!r field ( =ce1 l a magnetic field4 ,,direct-,,curr5t ,,dynamo4--,we %all n[ make ! simple/ =m ( dynamo1 us+ = ?is purpose a pair ( p]man5t magnets4 ,illu/ration3 ,fig4 #bb4 ,,dynamo ,,field ,,& ,,pole ,,piece ,,simple ,,magnet ,,con/ruction4--,a simple way to make a pair ( magnets = ?is purpose is %[n 9 ,fig4 #bb4 ,a piece ( r\nd #c_/d-;in* /eel core 7,a71 #e-a_/b in*es long1 is ?read$ at bo? ends to receive at "o end a nut 7,b71 :i* is screw$ on a suffici5t di/ance s t ! end ( ! core 7,a7 projects a half in* beyond ! nut4 ,! o!r end ( ! /eel core has a pole piece ( iron 7,c7 #b #b #d1 ) a hole midway betwe5 ! ends1 ?read$ entirely ?r\gh1 & provid$ along "o side ) a concave *annel1 )9 :i* ! armature is to turn4 ,n[1 be=e ! pole piece 7,c7 is put on1 we w slip on a disc 7,e71 made ( h>d rubb]1 !n a ?9 rubb] tube 7,f71 & f9ally a rubb] disc 7,g71 s z to provide a positive insulation = ! wire coil :i* is w\nd on ! bobb9 ?us made4 ,,h[ ,,to ,,w9d4--,9 practice1 & z y g fur!r along 9 ?is "w1 y w le>n ! value1 fir/1 ( w9d+ "o lay] ( insulat$ wire on ! spool1 coat+ x ) %ellac1 & !n putt+ on ! next lay]1 & s on2 :5 completely w\nd1 ! two wire t]m9als may be br\ght out at "o end2 b = our pres5t purpose1 & to r5d] ! explanation cle>]1 ! wire t]m9als are at ! opposite ends ( ! spool 7,h1 ,h'74 ,,! ,,dynamo ,,fields4--,two ( ^! spools are s made & !y are call$ ! fields ( ! dynamo4 ,we w next prep>e an iron b> 7,i71 #e in*es long & #a_/b in* ?ick & #a-a_/b in*es wide1 !n bore two holes ?r\gh x s ! di/ance measures #c in*es f c5t] to c5t]4 ,^! holes are to be ?read$ = ! #c_/d-;in* cores 7,a74 ,?is b> holds toge!r ! upp] ends ( ! cores1 z %[n 9 ,fig4 #bc4 ,illu/ration3 ,fig4 #bc4 ,,base ,,& ,,fields ,,assembl$ ,we !n prep>e a base 7,j7 ( any h>d wood1 #b in*es ?ick1 #h in*es long & #h in*es wide1 & bore two #c_/d-;in* holes #c in*es ap>t on a middle l9e1 to receive a pair ( #c_/d-;in* cap screws 7,k71 :i* pass upw>dly ?r\gh ! holes 9 ! base & screw into ! pole pieces 7,c74 ,a wood5 b> 7,l71 #a-a_/b #a-a_/b1 #h in*es long1 is plac$ "u ea* pole piece1 :i* is also provid$ ) holes = ! cap screws 7,k74 ,! l[] side ( ! base 7,j7 %\ld be c\nt]sunk1 z at ,m1 s ! head ( ! nut w n project4 ,! fields ( ! dynamo are n[ secur$ 9 position to ! base4 ,illu/ration3 ,fig4 #bd4 ,,details ,,( ,,! ,,armature1 ,,core ,fig4 #be4 ,,details ,,( ,,! ,,armature1 ,,body ,,! ,,armature4--,a b> ( iron 7,fig4 #bd71 #a #a & #b-a_/d in*es long1 is next provid$4 ,?r\gh ?is b> 7#a7 are !n bor$ two #e_/af-;in* holes #a-c_/d in*es ap>t1 & on ! opposite sides ( ?is b> are two half-r\nd$ plates ( iron 7#c7 7,fig4 #be74 ,,armature ,,w9d+4--,ea* plate is #a_/b in* ?ick1 #a-c_/d in*es wide & #d in*es long1 ea* plate hav+ holes 7#d7 to co9cide ) ! holes 7#b7 ( ! b> 7#a71 s t :5 ! two plates are appli$ to opposite sides ( ! b>1 & rivet$ toge!r1 a cyl9drical memb] is =m$1 ) two *annels runn+ longitud9ally1 & transv]sely at ! ends2 & 9 ^! *annels ! insulat$ wires are w\nd f end to end ar\nd ! c5tral block 7#a74 ,,m\nt+ ,,! ,,armature4--,x is n[ necess>y to provide a means = revolv+ ?is armature4 ,to ?is end a brass disc 7#e1 ,fig4 #bf7 is made1 #b in*es 9 diamet]1 #a_/h in* ?ick4 ,c5trally1 at "o side1 is a project+ /em 7#f7 ( r\nd brass1 :i* projects out #b in*es1 & ! out] end is turn$ d[n1 z at #g1 to =m a small be>+ surface4 ,illu/ration3 ,fig4 #bf4 ,,j\rnals ,fig4 #bg4 ,,commutator1 ,,armature ,,m\nt+s ,! o!r end ( ! armature has a simil> disc 7#h71 ) a c5tral /em 7#i71 #a-a_/b in*es long1 turn$ d[n to #a_/d-;in* diamet] up to )9 #a_/d in* ( ! disc 7#g71 s z to =m a %\ld]4 ,,! ,,commutator4--,9 ,fig4 #bg is %[n1 at #aj1 a wood5 cyl9d]1 #a in* long & #a-a_/d in*es 9 diamet]1 ) a hole 7#aa7 bor$ ?r\gh axially1 s t x w fit tightly on ! /em 7#f7 ( ! disc 7#e74 ,on ?is wood5 cyl9d] is driv5 a brass or copp] tube 7#ab71 :i* has holes 7#ac7 opposite ea* o!r4 ,screws are us$ to hold ! tube to ! wood5 cyl9d]1 & aft] !y are prop]ly secur$ toge!r1 ! tube 7#ab7 is cut by a saw1 z at #ad1 s z to =m two indep5d5t tubul> surfaces4 ,illu/ration3 ,fig4 #bh4 ,,end ,,view ,,armature1 ,,m\nt$ ,^! tubul> sections are call$ ! commutator plates4 ,illu/ration3 ,fig4 #bi4 ,,top ,,view ,,( ,,armature ,,on ,,base ,9 ord] to m\nt ?is armature1 two be>+s are provid$1 ea* compris+ a b> ( brass 7#ae1 ,fig4 #bh71 ea* #a_/d in* ?ick1 #a_/b in* wide & #d-a_/b in*es long4 ,two holes1 #c in*es ap>t1 are =m$ ?r\gh ?is b>1 to receive r\nd-head$ wood screws 7#af71 ^! screws be+ #c in*es long1 s !y w pass ?r\gh ! wood5 pieces 7,i7 & ent] ! base 7,j74 ,midway betwe5 ! ends1 ea* b> 7#ae7 has an iron be>+ block 7#ag71 #c_/d #a_/b & #a-a_/b in*es high1 ! #a_/d-;in* hole = ! j\rnal 7#g7 be+ midway betwe5 its ends4 ,,commutator ,,bru%es4--,fig4 #bh %[s ! base1 armature & commutator assembl$ 9 position1 & to ^! p>ts h be5 add$ ! commutator bru%es4 ,! bru% hold] 7#ah7 is a horizontal b> made ( h>d rubb] loosely m\nt$ ^u ! j\rnal p9 7#g71 :i* is #b-a_/b in*es long4 ,at ea* end is a "r-angl$ metal arm 7#ai7 secur$ to ! b> 7#ah7 by screws 7#bj74 ,to ^! arms ! bru%es 7#ba7 are atta*$1 s t _! spr+ ends engage ) ! commutator 7#ab74 ,an adju/+ screw 7#bb7 9 ! be>+ po/ 7#ag71 ) ! head !re( be>+ aga9/ ! bru%-hold] 7#ah71 s]ves z a means = revolubly adju/+ ! bru%es ) relation to ! commutator4 ,,dynamo ,,w9d+s4--,!re are sev]al ways to w9d ! dynamos4 ,^! c be %[n bett] by ! foll[+ diagrams 7,figs4 #cj1 #ca1 #cb1 #cc73 ,,! ,,field4--,if ! field 7,a1 ,fig4 #cj7 is n a p]man5t magnet1 x mu/ be excit$ by a cell or batt]y1 & ! wires 7,b1 ,b'7 are connect$ up ) a batt]y1 :ile ! wires 7,c1 ,c'7 may be connect$ up to run a motor4 ,?is w\ld1 !re=e1 be :at is call$ a sep>ately excit$ dynamo4 ,9 ?is case ! batt]y excites ! field & ! armature 7,d71 cutt+ ! l9es ( =ce at ! pole pieces 7,e71 s t ! armature ga!rs ! curr5t = ! wires 7,c1 ,c'74 ,illu/ration3 ,fig4 #cj4 ,,field ,,w9d+ ,illu/ration3 ,fig4 #ca4 ,,s]ies-,,w\nd ,,s]ies-,,w\nd ,,field4--,fig4 #ca %[s a s]ies-w\nd dynamo4 ,! wires ( ! fields 7,a7 are connect$ up 9 s]ies ) ! bru%es ( ! armature 7,d71 & ! wires 7,g1 ,g'7 are l$ out & connect$ up ) a lamp1 motor or o!r me*anism4 ,9 ?is case1 z well z 9 ,figs4 #cb & #cc1 bo? ! field & ! armature are made ( s(t gray iron4 ,) ?is w9d+ & means ( connect+ ! wires1 ! field is con/antly excit$ by ! curr5t pass+ ?r\gh ! wires4 ,,%unt-,,w\nd ,,field4--,fig4 #cb repres5ts :at is kn[n z a %unt-w\nd dynamo4 ,"h ! field wires 7,h1 ,h7 connect ) ! opposite bru%es ( ! armature1 & ! wires 7,i1 ,i'7 are also connect$ ) ! bru%es1 ^! two wires be+ provid$ to p]=m ! "w requir$4 ,?is is a m useful =m ( w9d+ = electroplat+ purposes4 ,illu/ration3 ,fig4 #cb4 ,,%unt-,,w\nd ,fig4 #cb4 ,,comp\nd-,,w\nd ,,comp\nd-,,w\nd ,,field4--,fig4 #cc is a diagram ( a comp\nd-w\nd dynamo4 ,! regul> field w9d+ 7,j7 has its opposite ends connect$ directly ) ! armature bru%es4 ,!re is also a w9d+1 ( a comp>atively few turns1 ( a ?ick] wire1 "o t]m9al 7,k7 ( :i* is connect$ ) "o ( ! bru%es & ! o!r t]m9al 7,k'7 =ms "o side ( ! light+ circuit4 ,a wire 7,l7 connects ) ! o!r armature bru% to =m a complete light+ circuit4 ,,*apt] ,v ,,h[ ,,to ,,detect ,,& ,,measure ,,electricity ,,measur+ ,,in/rum5ts4--,! production ( an electric curr5t w\ld n be ( mu* value unless we _h "s way by :i* we might detect & measure x4 ,! p\nd weight1 ! foot rule & ! qu>t measure are v simple devices1 b )\t !m v little bus9ess c\ld be done4 ,!re mu/ be a /&>d ( measurem5t 9 electricity z well z 9 deal+ ) iron or vegetables or fabrics4 ,z electricity _c be se5 by ! human eye1 "s me*anism mu/ be made :i* w reveal its movem5ts4 ,,! ,,detector4--,x has be5 %[n 9 ! prec$+ *apt] t a curr5t ( electricity pass+ ?r\gh a wire w cause a curr5t to pass ?r\gh a p>allel wire1 if ! two wires are plac$ close toge!r1 b n actually 9 contact ) ea* o!r4 ,an in/rum5t :i* reveals ?is condition is call$ a galvanomet]4 ,x n only detects ! pres5ce ( a curr5t1 b x %[s ! direction ( its fl[4 ,we %all n[ see h[ ?is is done4 ,= example1 ! wire 7,a1 ,fig4 #ce7 is connect$ up 9 an electric circuit ) a p]man5t magnet 7,b7 susp5d$ by a f9e wire 7,c71 s t ! magnet 7,b7 may freely revolve4 ,illu/ration3 ,fig4 #cd4 ,fig4 #ce4 ,fig4 #cf4 ,,to ,,! ,,"r1 ,,compass ,,magnet1 ,,to ,,! ,,left ,= conv5i5ce1 ! magnetic field is %[n fl[+ 9 ! direction ( ! d>ts1 9 :i* ! d>t 7,d7 repres5ts ! curr5t )9 ! magnet 7,b7 fl[+ t[>d ! nor? pole1 & ! d>ts 7,e7 %[+ ! ext]ior curr5t fl[+ t[>d ! s\? pole4 ,n[1 if ! wire 7,a7 is br\ght up close to ! magnet 7,b71 & a curr5t pass$ ?r\gh ,a1 ! magnet 7,b7 w be affect$4 ,fig4 #ce %[s ! normal condition ( ! magnetiz$ b> 7,b7 p>allel ) ! wire 7,a7 :5 a curr5t is n pass+ ?r\gh ! latt]4 ,,direction ,,( ,,curr5t4--,if ! curr5t %\ld g ?r\gh ! wire 7,a7 f "r to left1 z %[n 9 ,fig4 #cd1 ! magnet 7,b7 w\ld sw+ 9 ! direction tak5 by ! h&s ( a clock & assume ! position %[n 9 ,fig4 #cd4 ,if1 on ! o!r h&1 ! curr5t 9 ! wire 7,a7 %\ld be rev]s$ or fl[ f left to "r1 ! magnet 7,b7 w\ld sw+ c\nt]-clock-wise1 & assume ! position %[n 9 ,fig4 #cf4 ,! little po9t] 7,g7 w\ld1 9 ei!r case1 po9t 9 ! direction ( ! fl[ ( ! curr5t ?r\gh ! wire 7,a74 ,illu/ration3 ,fig4 #cg4 ,,indicat+ ,,direction ,,( ,,curr5t ,,simple ,,curr5t ,,detector4--,a simple curr5t detector may be made z foll[s3 ,prep>e a base #c' #d' 9 size & #a in* ?ick4 ,at ea* corn] ( "o end fix a b9d+ po/1 z at ,a1 ,a'1 ,fig4 #cg4 ,!n select #bj feet ( ,no4 #bh cotton-insulat$ wire1 & make a coil 7,b7 #b in*es 9 diamet]1 leav+ ! ends free1 s !y may be affix$ to ! b9d+ po/s 7,a1 ,a'74 ,n[ glue or nail six blocks 7,c7 to ! base1 ea* block be+ #a #a #b1 & lay ! coil on ^! blocks4 ,!n drive an ,l-%ap$ nail 7,d7 d[n into ea* block1 on ! inside ( ! coil1 z %[n1 s z to hold ! latt] 9 place4 ,illu/ration3 ,fig4 #ch4 ,,! ,,bridge ,n[ make a bridge 7,e1 ,fig4 #ch7 ( a /rip ( brass #a_/b in* wide1 #a_/af in* ?ick & long en\gh to span ! coil1 & b5d ! ends d[n1 z at ,f1 s z to =m legs4 ,a screw hole 7,g7 is =m$ 9 ea* foot1 s x may be screw$ to ! base4 ,midway betwe5 ! ends ?is bridge has a transv]se slot 7,h7 9 "o edge1 to receive !re9 ! pivot p9 ( ! sw++ magnet4 ,9 ord] to hold ! pivot p9 9 place1 cut out an ,h-%ap$ piece ( %eet brass 7,i71 :i*1 :5 laid on ! bridge1 has its ends b5t ar\nd ! latt]1 z %[n at ,j1 & ! crossb> ( ! ,h-%ap$ piece !n w prev5t ! pivot p9 f com+ out ( ! slot 7,h74 ,illu/ration3 ,fig4 #ci4 ,,details ,,( ,,detector ,! magnet is made ( a b> ( /eel 7,k1 ,fig4 #ci7 #a-a_/b in*es long1 #c_/h in* wide & #a_/af in* ?ick1 a piece ( a clock spr+ be+ v s]viceable = ?is purpose4 ,! pivot p9 is made ( an ord9>y p9 7,l71 & z x is difficult to sold] ! /eel magnet 7,k7 to ! p91 sold] only a small disc 7,m7 to ! p9 7,l74 ,!n bore a hole 7,n7 ?r\gh ! middle ( ! magnet 7,k71 l>g] 9 diamet] ?an ! p9 7,l71 &1 aft] putt+ ! p9 9 ! hole1 p\r seal+ wax into ! hole1 & !reby secure ! two p>ts toge!r4 ,ne> ! upp] end ( ! p9 7,l7 sold] ! end ( a po9t] 7,o71 ?is po9t] be+ at "r angles to ! armature 7,k74 ,x is bett] to h a metal socket = ! l[] end ( ! p94 ,:5 ^! p>ts are put toge!r1 z %[n 9 ,fig4 #cg1 a removable glass top1 or cov]1 %\ld be provid$4 ,?is is %[n 9 ,fig4 #dj1 9 :i* a squ>e1 wood5 frame 7,p7 is us$1 & a glass 7,q7 fitt$ into ! frame1 ! glass be+ s arrang$ t :5 ! cov] is 9 position x w be 9 close proximity to ! upp] project+ end ( ! pivot p9 7,l71 & ?us prev5t ! magnet f becom+ misplac$4 ,illu/ration3 ,fig4 #dj4 ,,cross ,,section ,,( ,,detector ,,h[ ,,to ,,place ,,! ,,detector4--,if ! detector is plac$ nor? & s\?1 z %[n by ! two m>k+s1 ,n & ,s 7,fig4 #cg71 ! magnet b> w po9t nor? & s\?1 be+ affect$ by ! e>?'s magnetism2 b :5 a curr5t ( electricity fl[s ?r\gh ! coil 7,b71 ! magnet w be deflect$ to ! "r or to ! left1 s t ! po9t] 7,o7 w !n %[ ! direction 9 :i* ! curr5t is fl[+ ?r\gh ! wire 7,r7 :i* y are te/+4 ,! next /ep ( importance is to measure ! curr5t1 t is1 to det]m9e its /r5g? or int5sity1 z well z ! fl[ or quantity4 ,,diff]5t ,,ways ,,( ,,measur+ ,a ,,curr5t4--,!re are sev]al ways to measure ! prop]ties ( a curr5t1 :i* may be def9$ z foll[s3 #a4 ,,! ,,sulphuric ,,acid ,,voltamet]4--,by means ( an electrolytic action1 :]eby ! curr5t decomposes an acidulat$ solution--t is1 wat] :i* has 9 x a small am\nt ( sulphuric acid--& !n measur+ ! gas g5]at$ by ! curr5t4 #b4 ,,! ,,copp] ,,voltamet]4--,by electro-*emical means1 9 :i* ! curr5t passes ?r\gh plates imm]s$ 9 a solution ( copp] sulphate4 #c4 ,,! ,,galvanoscope4--,by hav+ a coil ( insulat$ wire1 ) a magnet susp5d$ s z to turn freely )9 ! coil1 =m+ :at is call$ a galvanoscope4 #d4 ,,electro-,,magnetic ,,me?od4--,by us+ a pair ( magnets & s5d+ a curr5t ?r\gh ! coils1 & !n measur+ ! pull on ! armature4 #e4 ,,! ,,p[] ,,or ,,spe$ ,,me?od4--,by us+ an electric fan1 & not+ ! revolutions produc$ by ! curr5t4 #f4 ,,! ,,calorimet]4--,by us+ a coil ( b>e wire1 imm]s$ 9 p>aff9e oil1 & !n measur+ ! temp]ature by means ( a !rmomet]4 ,illu/ration3 ,fig4 #da4 ,,acid ,,voltamet] ,illu/ration3 ,fig4 #db4 ,,copp] ,,voltamet] #g4 ,,! ,,light ,,me?od4--,la/ly1 by means ( an electric light1 :i* %[s1 by its brightness1 a great] or less curr5t4 ,,! ,,pref]r$ ,,me?ods4--,x has be5 f\nd t ! fir/ & second me?ods are ! only ones :i* w accurately regi/] curr5t /r5g?1 & ^! me?ods h ?is advantage--t ! *emical effect produc$ is n dep5d5t ^u ! size or %ape ( ! app>atus or ! plates us$4 ,,h[ ,,to ,,make ,a ,,sulphuric ,,acid ,,voltamet]4--,9 ,fig4 #da is %[n a simple =m ( sulphuric acid voltamet]1 to illu/rate ! fir/ me?od4 ,a is a j>1 tightly clos$ by a cov] 7,b74 ,)9 is a pair ( plat9um plates 7,c1 ,c71 ea* hav+ a wire 7,d7 ?r\gh ! cov]4 ,! cov] has a v]tical glass tube 7,e7 ?r\gh x1 :i* ext5ds d[n to ! bottom ( ! j>1 ! electrolyte !re9 be+ a weak solution ( sulphuric acid4 ,:5 a curr5t passes ?r\gh ! wires 7,d71 ! solution is p>tially decompos$--t is1 conv]t$ into gas1 :i* passes up into ! vacant space 7,f7 above ! liquid1 &1 z x _c escape1 x presses ! liquid d[nw>dly1 & causes ! latt] to fl[ upw>dly into ! tube 7,e74 ,x is !n an easy matt]1 aft] ! curr5t is on = a c]ta9 "t1 to det]m9e its /r5g? by ! height ( ! liquid 9 ! tube4 ,,h[ ,,to ,,make ,a ,,copp] ,,voltamet]4--,! second1 or copp] voltamet]1 is %[n 9 ,fig4 #db4 ,! glass j> 7,a7 conta9s a solution ( copp] sulphate1 kn[n 9 comm]ce z blue vitriol4 ,a pair ( copp] plates 7,b1 ,b'7 are plac$ 9 ?is solution1 ea* be+ provid$ ) a connect+ wire 7,c74 ,:5 a curr5t passes ?r\gh ! wires 7,c71 "o copp] plate 7,b7 is eat5 away & deposit$ on ! o!r plate 7,b'74 ,x is !n an easy matt] to take out ! plates & f9d out h[ mu* 9 weight ,b' has ga9$1 or h[ mu* ,b has lo/4 ,9 ?is way1 9 comp>+ ! /r5g? (1 say1 two sep>ate curr5ts1 "o %\ld h ea* curr5t pass ?r\gh ! voltamet] ! same l5g? ( "t z ! o!r1 s z to obta9 comp>ative results4 ,x is n necess>y1 9 ! fir/ & second me?ods1 to consid] ! %apes1 ! sizes ( ! plates or ! di/ances betwe5 !m4 ,9 ! fir/ me?od ! gas produc$1 )9 a giv5 "t1 w be ! same1 & 9 ! second me?od ! am\nt deposit$ or eat5 away w be ! same "u all conditions4 ,,disadvantages ,,( ,,! ,,galvanoscope4--,) ! ?ird me?od 7us+ ! galvanoscope7 x is necess>y1 9 ord] to get a positively correct read+ in/rum5t1 to foll[ an absolutely accurate plan 9 con/ruct+ ea* "p1 9 e detail1 & great c>e mu/ be ex]cis$1 p>ticul>ly 9 w9d+4 ,x is necess>y also to be v c>eful 9 select+ ! sizes ( wire us$ & 9 ! numb] ( turns made 9 ! coils4 ,?is is equally true ( ! f\r? me?od1 us+ ! electro-magnet1 because ! magnetic pull is dep5d5t ^u ! size ( wire f :i* ! coils are made & ! numb] ( turns ( wire4 ,,objections ,,to ,,! ,,calorimet]4--,! calorimet]1 or six? me?od1 has ! same objection4 ,! galvanoscope & electro-magnet d n respond equally to all curr5ts1 & ?is is also true1 ev5 to a great] ext5t1 ) ! calorimet]4 ,,*apt] ,,vi ,,volts1 ,,amp]es1 ,,ohms ,,& ,,watts ,,und]/&+ ,,t]ms4--,we mu/ n[ try to asc]ta9 ! mean+ ( "s ( ! t]ms s frequ5tly us$ 9 connection ) electricity4 ,if y int5d$ to sell or measure produce or goods ( any k9d1 x w\ld be ess5tial to "k h[ _m p9ts or qu>ts are conta9$ 9 a gallon1 or 9 a bu%el1 or h[ _m in*es !re are 9 a y>d1 & y also ought to "k j :at ! quantity t]m bu%el or ! measurem5t y>d means4 ,,int5sity ,,& ,,quantity4--,electricity1 :ile x has no weight1 is capable ( be+ measur$ by means ( its int5sity1 or by its quantity4 ,light may be measur$ or te/$ by its brilliancy4 ,if "o light is ( less int5sity ?an ano!r & bo? ( !m receive _! impulses f ! same s\rce1 !re mu/ be some?+ :i* int]f]es ) t light :i* %[s ! lea/ brilliancy4 ,electricity c also be int]f]$ )1 & ?is int]f]5ce is call$ resi/ance4 ,,voltage4--,wat] may be made to fl[ ) great] or less =ce1 or velocity1 ?r\gh a pipe1 ! degree ( same dep5d+ ^u ! height ( ! wat] :i* supplies ! pipe4 ,s ) electricity4 ,x may pass ov] a wire ) great] or less =ce "u "o condition ?an ano!r4 ,?is =ce is call$ voltage4 ,if we h a l>ge pipe1 a mu* great] quantity ( wat] w fl[ ?r\gh x ?an w pass ?r\gh a small pipe1 provid+ ! pressure 9 ea* case is alike4 ,?is quantity 9 electricity is call$ amp]age4 ,9 ! case ( wat]1 a column #a #a1 #bh in*es 9 height1 weighs #a p\nd2 s t if a pipe #a in* squ>e draws wat] f ! bottom x fl[s ) a pressure ( #a p\nd4 ,if ! pipe has a measurem5t ( #b squ>e in*es1 d\ble ! quantity ( wat] w fl[ !refrom1 at ! same pressure4 ,,amp]age4--,if1 on ! o!r h&1 we h a pipe #a in* squ>e1 & !re is a dep? ( #ef in*es ( wat] 9 ! res]voir1 we %all get z mu* wat] f ! res]voir z ?\gh we _h a pipe ( #b squ>e in*es draw+ wat] f a res]voir :i* is #bh in*es deep4 ,,mean+ ,,( ,,watts4--,x is obvi\s1 !re=e1 t if we multiply ! height ( ! wat] 9 in*es ) ! area ( ! pipe1 we %all obta9 a factor :i* w %[ h[ mu* wat] is fl[+4 ,"h are two examples3 #a4 #bh in*es height ( ! wat] 9 ! res]voir4 #b squ>e in*es size ( ! pipe4 ,multiply #bh #b #ef4 #b4 #ef height ( ! wat] 9 ! res]voir4 #a squ>e in* size ( ! pipe4 ,multiply #ef #a #ef4 ,?us ! two problems are equal4 ,a ,,kil[att4--,n[1 9 electricity1 rememb]+ t ! height ( ! wat] corresponds ) voltage 9 electricity1 & ! size ( ! pipe ) amp]age1 if we multiply volts by amp]es1 or amp]es by volts1 we get a result :i* is indicat$ by ! t]m watts4 ,"o ?\s& ( ^! watts make a kil[att1 & ! latt] is ! /&>d ( measurem5t by :i* a dynamo or motor is judg$ or rat$4 ,?us1 if we h #e amp]es & #aaj volts1 ! result ( multiply+ !m w\ld be #eej watts1 or #e volts & #aaj amp]es w\ld produce #eej watts4 ,a ,,/&>d ,,( ,,measurem5t4--,b ) all ?is we mu/ h "s /&>d4 ,a bu%el measure is ( a c]ta9 size1 & a foot has a def9ite l5g?1 s 9 electricity !re is a recogniz$ =ce & quantity :i* are det]m9$ z foll[s3 ,,! ,,amp]e ,,/&>d4--,x is necess>y1 fir/1 to det]m9e :at an amp]e is4 ,= ?is purpose a /&>d solution ( nitrate ( silv] is us$1 & a curr5t ( electricity is pass$ ?r\gh ?is solution4 ,9 do+ s ! curr5t deposits silv] at ! rate ( #j4jjaaah gra9s p] second = ea* amp]e4 ,,! ,,voltage ,,/&>d4--,9 ord] to det]m9e ! voltage we mu/ "k some?+ ( resi/ance4 ,diff]5t metals d n transmit a curr5t ) equal ease4 ,! size ( a conductor1 also1 is an important factor 9 ! passage ( a curr5t4 ,a l>ge conductor w transmit a curr5t mu* bett] ?an a small conductor4 ,we mu/ !re=e h a /&>d = ! ohm1 :i* is ! measure ( resi/ance4 ,,! ,,ohm4--,x is calculat$ 9 ?is way3 ,!re are sev]al /&>ds1 b ! "o mo/ g5]ally employ$ is ! ,int]national ,ohm4 ,to det]m9e x1 by ?is sy/em1 a column ( pure m]cury1 #ajf4c millimet]s long & weigh+ #ad4deba grams1 is us$4 ,?is w\ld make a squ>e tube ab\t #id in*es long1 & a little ov] #a_/be ( an in* 9 diamet]4 ,! resi/ance to a curr5t fl[ 9 su* a column w\ld be equal to #a ohm4 ,,calculat+ ,,! ,,voltage4--,9 ord] to arrive at ! voltage we mu/ use a conductor1 :i*1 ) a resi/ance ( #a ohm1 w produce #a amp]e4 ,x mu/ be rememb]$ t ! volt is ! practical unit ( electro-motive =ce4 ,:ile x w\ld be difficult = ! boy to conduct ^! exp]im5ts 9 ! abs5ce ( suitable app>atus1 /ill1 x is well to und]/& ?or\ghly h[ & :y ^! /&>ds are made & us$4 ,,*apt] ,,vii ,,pu% ,,buttons1 ,,swit*es1 ,,annunciators1 ,,bells ,,& ,,l ,,app>atus ,,simple ,,swit*es4--,we h n[ gone ov] ! simpl] or elem5t>y outl9es ( electrical ph5om5a1 & we may comm5ce to d "s ( ! practical "w 9 ! art4 ,we ne$ c]ta9 app>atus to make connections1 :i* w be con/ruct$ fir/4 ,a ,,two-,,pole ,,swit*4--,a simple two-pole swit* = a s+le l9e is made z foll[s3 ,a base block 7,a1 ,fig4 #dc7 #c in*es long1 #b in*es wide & #c_/d in* ?ick1 has on x1 at "o end1 a b9d+ screw 7,b71 :i* holds a pair ( f+]s 7,c7 ( brass or copp]1 ^! f+]s be+ b5t upw>dly & s arrang$ z to s]ve z f+]s to hold a swit* b> 7,d7 betwe5 !m4 ,?is b> is also ( copp] or brass & is pivot$ to ! f+]s4 ,ne> ! o!r end ( ! base is a simil> b9d+ screw 7,e7 & f+]s 7,f7 to receive ! blade ( ! swit* b>4 ,! b> has a h&le 7,g7 ( wood4 ,! wires are atta*$ to ! respective b9d+ screws 7,b1 ,e74 ,,d\ble-,,pole ,,swit*4--,a d\ble-pole swit* or a swit* = a d\ble l9e is %[n 9 ,fig4 #dd4 ,?is is made simil> 9 all respects to ! "o %[n 9 ,fig4 #dc1 except+ t !re are two swit* blades 7,a1 ,a7 connect$ by a cross b> 7,b7 ( insulat+ mat]ial1 & ?is b> c>ries ! h&le 7,c74 ,illu/ration3 ,fig4 #dc4 ,,two-,,pole ,,swit* ,illu/ration3 ,fig4 #dd4 ,,d\ble-,,pole ,,swit* ,o!r types ( swit* w be f\nd v useful4 ,9 ,fig4 #de is a simple slid+ swit* 9 :i* ! base block has1 at "o end1 a pair ( copp] plates 7,a1 ,b71 ea* held at "o end to ! base by a b9d+ screw 7,c71 & hav+ a be>+ or contact surface 7,d7 at its o!r end4 ,at ! o!r end ( ! base is a copp] plate 7,e7 held by a b9d+ screw 7,f71 to ! inn] end ( :i* plate is h+$ a sw++ swit* blade 7,g71 ! free end ( :i* is adapt$ to engage ) ! plates 7,a1 ,b74 ,illu/ration3 ,fig4 #de4 ,,slid+ ,,swit* ,,slid+ ,,swit*4--,?is slid+ swit* =m may h ! contact plates 7,a1 ,b & ,c1 ,fig4 #df7 circul>ly arrang$ & any numb] may be locat$ on ! base1 s !y may be engag$ by a s+le swit*+ lev] 7,h74 ,x is ! =m usually adopt$ = rheo/ats4 ,,rev]s+ ,,swit*4--,a rev]s+ swit* is %[n 9 ,fig4 #dg4 ,! base has two plates 7,a1 ,b7 at "o end1 to :i* ! p>allel swit* b>s 7,c1 ,d7 are h+$4 ,! o!r end ( ! base has ?ree contact plates 7,e1 ,f1 ,g7 to engage ! sw++ swit* b>s1 ^! latt] be+ at su* di/ance ap>t t !y w engage ) ! middle & "o ( ! out] plates4 ,! inlet wires1 positive & negative1 are atta*$ to ! plates 7,a1 ,b1 respectively71 & "o ( ! outlet wires 7,h7 is atta*$ to ! middle contact plate 7,f71 :ile ! o!r wire is connect$ up ) bo? ( ! outside plates4 ,:5 ! swit* b>s 7,c1 ,d7 are ?r[n to ! left s z to be 9 contact ) ,e1 ,f1 ! outside plate 7,e7 & ! middle plate 7,f7 w be positive & negative1 respectively2 b :5 ! swit* is ?r[n to ! "r1 z %[n 9 ! figure1 plate ,f becomes positive & plate ,e negative1 z %[n4 ,illu/ration3 ,fig4 #df4 ,,rheo/at ,,=m ,,( ,,swit* ,,pu% ,,buttons4--,a pu% button is b a modifi$ /ructure ( a swit*1 & !y are s]viceable because !y are op]at+1 or ! circuit is =m$ only :ile ! f+] is on ! button4 ,illu/ration3 ,fig4 #dg4 ,,rev]s+ ,,swit* ,9 its simple/ =m 7,fig4 #dh7 ! pu% button has m]ely a circul> base 7,a7 ( insulat+ mat]ial1 & ne> "o m>g91 on ! flat side1 is a rectangul> plate 7,b71 int5d$ to s]ve z a contact plate z well z a means = atta*+ "o ( ! wires !reto4 ,9 l9e ) ?is plate is a spr+ f+] 7,c71 b5t upw>dly s t x is normally out ( contact ) ! plate 7,b71 its end be+ held by a b9d+ screw 7,d74 ,to effect contact1 ! spr+ end ( ! f+] 7,c7 is press$ aga9/ ! b> 7,b71 z at ,e4 ,?is is enclos$ 9 a suitable cas+1 su* z w readily sugge/ itself to ! novice4 ,,electric ,,bell4--,"o ( ! fir/ ?+s ! boy wants to make1 & "o :i* is also an int]e/+ piece ( "w1 is an electric bell4 ,to make ?is he w be br\ght1 exp]im5tally1 9 t\* ) sev]al important features 9 electrical "w4 ,he mu/ make a batt]y = ! production ( curr5t1 a pair ( electro-magnets to be act$ ^u by ! curr5t1 a swit* to control x1 &1 f9ally1 he mu/ le>n h[ to connect x up s t x may be op]at$ n only f "o1 b f two or m pu% buttons4 ,illu/ration3 ,fig4 #dh4 ,,pu% ,,button ,,h[ ,,made4--,9 ,fig4 #di is %[n an electric bell1 z usually con/ruct$1 s modifi$ z to %[ ! /ructure at a glance1 ) its connections4 ,a is ! base1 ,b1 ,b' ! b9d+ po/s = ! wires1 ,c1 ,c ! electro-magnets1 ,c' ! bracket = hold+ ! magnets1 ,d ! armature1 ,e ! ?9 spr+ :i* connects ! armature ) ! po/ ,f1 ,g ! clapp] arm1 ,h ! bell1 ,i ! adju/+ screw on ! po/ ,j1 ,k ! wire lead f ! b9d+ po/ ,b to ! fir/ magnet1 ,l ! wire :i* connects ! two magnets1 ,m ! wire :i* runs f ! second magnet to ! po/ ,j1 & ,n a wire lead+ f ! armature po/ to ! b9d+ po/ ,b'4 ,illu/ration3 ,fig4 #di4 ,,electric ,,bell ,! pr9ciple ( ! electric bell is ?is3 ,9 look+ at ,fig4 #di1 y w note t ! armature b> ,d is held aga9/ ! end ( ! adju/+ screw by ! small spr+ ,e4 ,:5 a curr5t is turn$ on1 x passes ?r\gh ! connections & conduits z foll[s3 ,wire ,k to ! magnets1 wire ,m to ! b9d+ po/ ,j1 & set screw ,i1 !n ?r\gh ! armature to ! po/ ,f1 & f po/ ,f to ! b9d+ po/ ,b'4 ,illu/ration3 ,fig4 #ej4 ,,armature ,,( ,,electric ,,bell ,,electric ,,bell--,,h[ ,,op]at$4--,! mom5t a curr5t passes ?r\gh ! magnets 7,c1 ,c71 ! core is magnetiz$1 & ! result is t ! armature 7,d7 is attract$ to ! magnets1 z %[n by ! dott$ l9es 7,o71 :5 ! clapp] /rikes ! bell4 ,b :5 ! armature moves ov] to ! magnet1 ! connection is brok5 betwe5 ! screw 7,i7 & armature 7,d71 s t ! cores ( ! magnets are demagnetiz$ & lose _! pull1 & ! spr+ 7,e7 succe$s 9 draw+ back ! armature4 ,?is op]ation ( vibrat+ ! armature is repeat$ ) great rapidity1 alt]nately break+ & re-e/abli%+ ! circuit1 by ! action ( ! curr5t4 ,9 mak+ ! bell1 y mu/ obs]ve "o ?+1 ! b9d+ po/s 7,b1 ,b'7 mu/ be insulat$ f ea* o!r1 & ! po/ ,j1 or ! po/ ,f1 %\ld also be insulat$ f ! base4 ,= conv5i5ce we %[ ! po/ ,f insulat$1 s z to necessitate ! use ( wire 7,n7 f po/ 7,f7 to b9d+ po/ 7,b'74 ,! =ego+ assumes t y h us$ a ca/ metal base1 z mo/ bells are n[ made2 b if y use a wood5 base1 ! b9d+ po/s 7,b1 ,b'7 & ! po/s 7,f1 ,j7 are insulat$ f ea* o!r1 & ! con/ruction is mu* simplifi$4 ,x is bett]1 9 practice1 to h a small spr+ 7,p1 ,fig4 #ej7 betwe5 ! armature 7,d7 & ! end ( ! adju/+ screw 7,i71 s z to give a return impetus to ! clapp]4 ,! object ( ! adju/+ screw is to pu% & hold ! armature close up to ! ends ( ! magnets1 if x seems necess>y4 ,if two bells are plac$ on ! base ) ! clapp] m\nt$ betwe5 !m1 bo? bells w be /ruck by ! sw++ motion ( ! armature4 ,an easily removable cap or cov] is usually plac$ ov] ! coils & armature1 to keep out du/4 ,a v simple annunciator may be atta*$ to ! bell1 z %[n 9 ! foll[+ figures3 ,illu/ration3 ,figs4 #ea-ed4 ,,annunciator ,,annunciators4--,make a box ( wood1 ) a base 7,a7 #d #e & #a_/b in* ?ick4 ,on ?is y c p]man5tly m\nt ! two side pieces 7,b7 & two top & bottom pieces 7,c71 respectively1 s !y project outw>dly #d-a_/b in*es f ! base4 ,on ! op5 front place a wood or metal plate 7,d71 provid$ ) a squ>e op5+ 7,d71 z 9 ,fig4 #ed1 ne> its l[] end4 ,?is plate is held to ! box by screws 7,e74 ,)9 is a magnet 7,f71 screw$ into ! base 7,a71 z %[n 9 ,fig4 #ea2 & pivot$ to ! bottom ( ! box is a v]tical armature 7,g71 :i* ext5ds upw>dly & contacts ) ! core ( ! magnet4 ,! upp] end ( ! armature has a %\ld] 7,h71 :i* is 9 su* position t x s]ves z a re/ = a ,v-%ap$ /irrup 7,i71 :i* is h+$ at ,j to ! base 7,c74 ,?is /irrup c>ries ! numb] plate 7,k71 & :5 x is rais$ to its highe/ po9t x is held on ! %\ld] 7,h71 unless ! electro-magnet draws ! armature out ( range ( ! /irrup4 ,a spr+ 7,l7 be>+ aga9/ ! inn] side ( ! armature keeps its upp] end normally away f ! magnet core4 ,:5 ! magnet draws ! armature inw>dly1 ! numb] plate drops & exposes ! num]al ?r\gh ! op5+ 9 ! front ( ! box4 ,9 ord] to return ! numb] plate to its orig9al position1 z %[n 9 ,fig4 #ea1 a v]tical trigg] 7,m7 passes up ?r\gh ! bottom1 its upp] end be+ )9 range ( "o ( ! limbs ( ! /irrup4 ,?is is easily made by ! +5i\s boy1 & w be q an acquisition to 8 /ock ( in/rum5ts4 ,9 practice1 ! annunciator may be locat$ 9 any conv5i5t place & wires run to t po9t4 ,illu/ration3 ,fig4 #ee4 ,,al>m ,,swit* ,,on ,,w9d[ ,illu/ration3 ,fig4 #ef4 ,,burgl> ,,al>m ,,atta*m5t ,,to ,,w9d[ ,,burgl> ,,al>m4--,9 ord] to make a burgl> al>m connection ) a bell1 pu% buttons or swit*es may be put 9 circuit to connect ) ! w9d[s & doors1 & by means ( ! annunciators y may locate ! door or w9d[ :i* has be5 op5$4 ,! simple/ =m ( swit* = a w9d[ is %[n 9 ! foll[+ figures3 ,! base piece 7,a71 :i* may be ( h>d rubb] or fib]1 is #a_/d in* ?ick & #a #a-a_/b 9 size4 ,illu/ration3 ,fig4 #eg4 ,,burgl> ,,al>m ,,contact ,at "o end is a brass plate 7,b71 ) a hole = a wood screw 7,c71 ?is screw be+ design$ to pass ?r\gh ! plate & also into ! w9d[-frame1 s z to s]ve z a means ( atta*+ "o ( ! wires !reto4 ,! inn] end ( ! plate has a hole = a r\nd-head$ screw 7,c'7 t also goes ?r\gh ! base & into ! w9d[-frame4 ,x also passes ?r\gh ! l[] end ( ! he>t-%ap$ metal swit*-piece 7,d74 ,! upp] end ( ! base has a brass plate 7,e71 also secur$ to ! base & w9d[ by a screw 7,f7 at its upp] end4 ,! he>t-%ap$ swit* is ( su* l5g? & wid? at its upp] end t :5 x is swung to ! "r ) "o ( ! lobes project+ pa/ ! edge ( ! w9d[-frame1 ! o!r lobe w be out ( contact ) ! plate 7,e74 ,illu/ration3 ,fig4 #eh4 ,,neutral ,,position ,,( ,,contact ,! w9d[ sa% 7,g7 has a removable p9 7,h71 :i*1 :5 ! sa% moves upw>dly1 is 9 ! pa? ( ! lobe ( ! he>t-%ap$ swit*1 z %[n 9 ,fig4 #ef1 & 9 ?is mann] ! p9 7,h7 moves ! upp] end ( ! swit* 7,d7 inw>dly1 s t ! o!r lobe contacts ) ! plate 7,e71 & e/abli%es an electric circuit1 z %[n 9 ,fig4 #eg4 ,dur+ ! daytime ! p9 7,h7 may be remov$1 & 9 ord] to protect ! swit* ! he>t-%ap$ piece 7,d7 is swung inw>dly1 z %[n 9 ,fig4 #eh1 s t nei!r ( ! lobes is 9 contact ) ! plate 7,e74 ,,wire ,,circuit+4--,= ! purpose ( und]/&+ fully ! circuit+1 diagrams w be %[n ( ! simple electric bell ) two pu% buttons2 next 9 ord]1 ! circuit+ ) an annunciator & !n ! circuit+ necess>y = a s]ies ( w9d[s & doors1 ) annunciator atta*m5ts4 ,illu/ration3 ,fig4 #ei4 ,,circuit+ ,,= ,,electric ,,bell ,,circuit+ ,,sy/em ,,) ,a ,,bell ,,& ,,two ,,pu% ,,buttons4--,fig4 #ei %[s a simple circuit+ sy/em :i* has two pu% buttons1 al?\gh any numb] may be us$1 s t ! bell w r+ :5 ! circuit is clos$ by ei!r button4 ,,! ,,pu% ,,buttons ,,& ,,! ,,annunciator ,,bells4--,fig4 #fj %[s ?ree pu% buttons & an annunciator = ea* button4 ,^! ?ree circuits are indicat$ by ,a1 ,b & ,c1 s t :5 ei!r button makes contact1 a complete circuit is =m$ ?r\gh ! correspond+ annunciator4 ,illu/ration3 ,fig4 #fj4 ,annunciators ,illu/ration3 ,fig4 #fa4 ,,wir+ ,,sy/em ,,= ,a ,,h\se ,,wir+ ,,up ,a ,,h\se4--,! sy/em ( wir+ up a h\se s t all doors & w9d[s w be connect$ to =m a burgl> al>m outfit1 is %[n 9 ,fig4 #fa4 ,x w be und]/ood t1 9 practice1 ! bell is m\nt$ on or at ! annunciator1 & t1 = conv5i5ce1 ! annunciator box has also a receptacle = ! batt]y4 ,! circuit+ is %[n diagramatically1 z x is call$1 s z fully to expla9 h[ ! l9es are run4 ,two w9d[s & a door are connect$ up ) an annunciator hav+ ?ree drops1 or numb]s #a1 #b1 #c4 ,! circuit runs f "o pole ( ! batt]y to ! bell & !n to "o po/ ( ! annunciator4 ,f ! o!r po/ a wire runs to "o t]m9al ( ! swit* at ! door or w9d[4 ,! o!r swit* t]m9al has a wire runn+ to ! o!r pole ( ! batt]y4 ,a1 ,b1 ,c repres5t ! circuit wires f ! t]m9als ( ! w9d[ & door swit*es1 to ! annunciators4 ,x is entirely immat]ial :i* side ( ! batt]y is connect$ up ) ! bell4 ,f ! =ego+ x w readily be und]/ood h[ to connect up any ord9>y app>atus1 rememb]+ t 9 all cases ! magnet mu/ be br\ght into ! electric circuit4 ,,*apt] ,,viii ,,accumulators4 ,,/orage ,,or ,,second>y ,,batt]ies ,,/or+ ,,up ,,electricity4--,9 ! =ego+ *apt]s we h se5 t1 orig9ally1 electricity 0 conf9$ 9 a bottle1 call$ ! ,leyd5 j>1 f :i* x 0 :olly dis*>g$ at a s+le impulse1 z soon z x 0 connect$ up by ext]nal means4 ,lat] ! prim>y batt]y & ! dynamo 7 inv5t$ to g5]ate a con/ant curr5t1 & aft] ^! came ! second =m ( /or+ electricity1 call$ ! /orage or second>y batt]y1 & lat] /ill recogniz$ z accumulators4 ,,! ,,accumulator4--,! t]m accumulator is1 /rictly speak+1 ! m ne>ly correct1 z electricity is1 9 reality1 /or$ 9 an accumulator4 ,b :5 an accumulator is *>g$ by a curr5t ( electricity1 a *emical *ange is gradually produc$ 9 ! active elem5t ( :i* ! accumulator is made4 ,?is *ange or decomposition cont9ues s long z ! *>g+ curr5t is on4 ,:5 ! accumulator is disconnect$ f ! *>g+ batt]y or dynamo1 & its t]m9als are connect$ up ) a light+ sy/em1 or ) a motor1 = in/ance1 a rev]se process is set up1 or ! p>ticles re-=m !mselves into _! orig9al compositions1 :i* causes a curr5t to fl[ 9 a direction opposite to t ( ! *>g+ curr5t4 ,x is immat]ial to ! purposes ( ?is *apt]1 z to ! *>g+ s\rce1 :e!r x be by batt]ies or dynamos2 ! same pr9ciples w apply 9 ei!r case4 ,illu/ration3 ,fig4 #fb4 ,,accumulator ,,grids ,,accumulator ,,plates4--,! elem5ts us$ = accumulator plates are r$ lead = ! positive plates1 & precipitat$ lead1 or ! well-kn[n li?>ge1 = ! negative plates4 ,exp]i5ce has %[n t ! be/ way to hold ?is mat]ial is by means ( lead grids4 ,fig4 #fb %[s ! typical =m ( "o ( ^! grids4 ,x is made ( lead1 ca/ or mold$ 9 "o piece1 usually squ>e1 z at ,a1 ) a w+ or projection 7,b71 at "o m>g91 ext5d+ upw>dly & provid$ ) a hole 7,c74 ,! grid is ab\t a qu>t] ( an in* ?ick4 ,,! ,,grid4--,! op5 space1 call$ ! grid1 prop]1 comprises cross b>s1 integral ) ! plate1 made 9 a v>iety ( %apes4 ,fig4 #fb %[s ?ree =ms ( con/ruct+ ^! b>s or ribs1 ! object be+ to provide a =m :i* w hold 9 ! lead pa/e1 :i* is press$ 9 s z to make a solid-look+ plate :5 complet$4 ,,! ,,positive ,,plate4--,! positive plate is made 9 ! foll[+ mann]3 ,make a /iff pa/e ( r$ lead & sulphuric acid2 us+ a solution1 say1 ( "o "p ( acid to two p>ts ( wat]4 ,! grid is laid on a flat surface & ! pa/e =c$ into ! p]=ations ) a /iff knife or spatula4 ,turn ov] ! grid s z to get ! pa/e 9 ev5ly on bo? sides4 ,! grid is !n /ood on its edge1 f #ah to #bj h\rs1 to dry1 & aft]w>ds imm]s$ 9 a conc5trat$ solution ( *loride ( lime1 s z to conv]t x into lead p]oxide4 ,:5 ! action is complete x is ?or\ghly r9s$ 9 cold wat]1 & is ready to use4 ,,! ,,negative ,,plate4--,! negative plate is fill$1 9 l mann]1 ) precipitat$ lead4 ,?is lead is made by putt+ a /rip ( z9c into a /&>d solution ( acetate ( lead1 & cry/als w !n =m on ! z9c4 ,^! w be v ?91 & w adh]e toge!r1 firmly1 =m+ a por\s mass4 ,?is1 :5 saturat$ & kept "u wat] = a %ort "t1 may be put into ! op5+s ( ! negative plate4 ,illu/ration3 ,fig4 #fc4 ,,assemblage ,,( ,,accumulator ,,plates ,,connect+ ,,up ,,! ,,plates4--,! next /ep is to put ^! plates 9 position to =m a batt]y4 ,9 ,fig4 #fc is %[n a collection ( plates connect$ toge!r4 ,= simplicity 9 illu/rat+1 ! cell is made up ( glass1 porcela91 or h>d rubb]1 ) five plates 7,a71 ,a1 ,a repres5t+ ! negative & ,b1 ,b ! positive plates4 ,a base ( groov$ /rips 7,c1 ,c7 is plac$ 9 ! batt]ies ( ! cell to receive ! l[] ends ( ! plates4 ,! positive plates are held ap>t by means ( a %ort section ( tub+ 7,d71 :i* is clamp$ & held )9 ! plates by a bolt 7,e71 ?is bolt also be+ design$ to hold ! t]m9al /rip 7,f74 ,9 l mann]1 ! negative plates are held ap>t by ! two tubul> sections 7,g71 ea* ( :i* is ( ! same l5g? z ! section ,d ( ! positives4 ,! bolt 7,h7 holds ! negatives toge!r z well z ! t]m9al 7,i74 ,! t]m9als %\ld be lead /rips1 & x w\ld be well1 ow+ to ! acid fumes :i* are =m$1 to coat all brass "w1 screws1 etc41 ) p>aff9e wax4 ,! electrolyte or acid us$ 9 ! cell1 = work+ purposes1 is a pure sulphuric acid1 :i* %\ld be dilut$ ) ab\t f\r times its weight 9 wat]4 ,rememb]1 y %\ld always add ! /rong acid to ! wat]1 & nev] p\r ! wat] into ! acid1 z ! latt] me?od causes a dang]\s ebullition1 & does n produce a good mixture4 ,put en\gh ( ?is solution into ! cell to cov] ! tops ( ! plates1 & ! cell is ready4 ,illu/ration3 ,fig4 #fd4 ,,connect+ ,,up ,,/orage ,,batt]y ,,9 ,,s]ies ,,*>g+ ,,! ,,cells4--,! *>ge ( ! curr5t mu/ nev] be less ?an #b4e volts4 ,ea* cell has an output1 9 voltage1 ( ab\t #b volts1 h5ce if we h1 say1 #aj cells1 we mu/ h at lea/ #be volts *>g+ capacity4 ,we may arrange ^! 9 "o l9e1 or 9 s]ies1 z x is call$1 s f> z ! connections are conc]n$1 & *>ge !m ) a dynamo1 or o!r electrical s\rce1 :i* %[s a pressure ( #be volts1 z illu/rat$ 9 ,fig4 #fd1 or1 in/ead ( ?is1 we may put !m into two p>allel sets ( #e cells ea*1 z %[n 9 ,fig4 #fe1 & use #ab4e volts to *>ge )4 ,9 ?is case x w take d\ble ! "t because we are *>g+ ) only "o-half ! voltage us$ 9 ! fir/ case4 ,! positive pole ( ! dynamo %\ld be connect$ ) ! positive pole ( ! accumulator cell1 & negative ) negative4 ,:5 ?is has be5 done run up ! ma*9e until x slightly exce$s ! voltage ( ! cells4 ,?us1 if we h #ej cells 9 p>allel1 l 9 ,fig4 #fd1 at lea/ #abe volts w be requir$1 & ! excess necess>y %\ld br+ up ! voltage 9 ! dynamo to #ace or #adj volts4 ,illu/ration3 ,fig4 #fe4 ,,p>allel ,,s]ies ,illu/ration3 ,fig4 #ff4 ,,*>g+ ,,circuit ,,! ,,initial ,,*>ge4--,x is usual initially to *>ge ! batt]y f p]iods rang+ f #cf to #dj h\rs1 & to let x /& = #ab or #ae h\rs1 aft] :i* to re-*>ge1 until ! positive plates h turn$ to a *ocolate color1 & ! negative plates to a slate or gray color1 & bo? plates give (f l>ge bubbles ( gas4 ,9 *>g+1 ! temp]ature ( ! electrolyte %\ld n exce$ #ajj ,fahr5heit4 ,:5 us+ ! accumulators !y %\ld nev] be fully dis*>g$4 ,,! ,,*>g+ ,,circuit4--,! diagram 7,fig4 #ff7 %[s h[ a *>g+ circuit is =m$4 ,! lamps are connect$ up 9 p>allel1 z illu/rat$4 ,ea* #af-;c&le-p[] #aje-volt lamp w c>ry #a_/b amp]e1 s t1 suppos+ we h a dynamo :i* gives #aaj volts1 & we want to *>ge a #d-volt accumulator1 !re w be #e-volt surplus to g to ! accumulator4 ,if1 = in/ance1 y want ! cell to h a *>ge ( #b amp]es1 f\r ( ^! lamps %\ld be connect$ up 9 p>allel4 ,if #c amp]es are requir$1 use #f lamps1 & s on4 ,,*apt] ,,ix ,,! ,,telegraph ,! telegraph is a v simple in/rum5t4 ,! key is no?+ m or less ?an a swit* :i* turns ! curr5t on & (f alt]nately4 ,! signals s5t ov] ! wires are simply ! audible s\nds made by ! armature1 z x moves to & f ! magnets4 ,,me*anism ,,9 ,,telegraph ,,circuits4--,a telegraph circuit requires ?ree pieces ( me*anism at ea* /ation1 namely1 a key us$ by ! s5d]1 a s\nd] = ! receiv]1 & a batt]y4 ,,! ,,s5d+ ,,key4--,! base ( ! s5d+ in/rum5t is six in*es long1 f\r in*es wide1 & ?ree-qu>t]s ( an in* ?ick1 made ( wood1 or any suitable non-conduct+ mat]ial4 ,! key 7,a7 is a piece ( brass ?ree-eigh?s by "o-half in* 9 ?ickness & six in*es long4 ,midway betwe5 its ends is a cross hole1 to receive ! pivot p9 7,b71 :i* also passes ?r\gh a pair ( metal brackets 7,c1 ,d71 ! bracket ,c hav+ a screw to hold "o ( ! l9e wires1 & ! o!r bracket hav+ a metal swit* 7,e7 h+$ !reto4 ,?is swit* b>1 l ! brackets1 is made ( brass1 "o-half in* wide by "o-sixte5? ( an in* ?ick4 ,bel[ ! =w>d end ( ! key 7,a7 is a cross b> ( brass 7,f71 screw$ to ! base by a screw at "o end1 to receive ! o!r l9e wire4 ,directly bel[ ! key 7,a7 is a screw 7,g71 s t ! key w /rike x :5 mov$ d[nw>dly4 ,! o!r end ( ! b> 7,f7 contacts ) ! =w>d end ( ! swit* b> 7,e7 :5 ! latt] is mov$ inw>dly4 ,illu/ration3 ,fig4 #fg4 ,,telegraph ,,s5d+ ,,key ,! =w>d end ( ! key 7,a7 has a knob 7,h7 = ! f+]s1 & ! re> end has an ela/ic 7,i7 atta*$ !reto :i* is secur$ to ! end ( ! base1 s t1 normally1 ! re> end is held aga9/ ! base & away f ! screw head 7,g74 ,! head 7,j7 ( a screw projects f ! base at its re> end4 ,key ,a contacts ) x4 ,:5 ! key ,a contacts ) ! screw heads ,g1 ,j1 a click is produc$1 "o :5 ! key is press$ d[n & ! o!r :5 ! key is releas$4 ,y w notice t ! two plates ,c1 ,f are connect$ up 9 circuit ) ! batt]y1 s t1 z ! swit* ,e is ?r[n1 s z to be out ( contact1 ! circuit is op51 & may be clos$ ei!r by ! key ,a or ! swit* ,e4 ,! use ( ! swit* w be illu/rat$ 9 connection ) ! s\nd]4 ,illu/ration3 ,fig4 #fh4 ,,telegraph ,,s\nd] ,:5 ! key ,a is depress$1 ! circuit ( c\rse goes ?r\gh plate ,c1 key ,a & plate ,f to ! /ation signall$4 ,,! ,,s\nd]4--,! s\nd] is ! in/rum5t :i* c>ries ! electro-magnet4 ,9 ,fig4 #fh ?is is %[n 9 p]spective4 ,! base is six in*es long & f\r in*es wide1 be+ made1 pref]ably1 ( wood4 ,ne> ! =w>d end is m\nt$ a pair ( electro-magnets 7,a1 ,a71 ) _! t]m9al wires connect$ up ) plates ,b1 ,b'1 to :i* ! l9e wires are atta*$4 ,midway betwe5 ! magnets & ! re> end ( ! base is a pair ( upw>dly project+ brackets 7,c74 ,betwe5 ^! are pivot$ a b> 7,d71 ! =w>d end ( :i* re/s betwe5 ! magnets & c>ries1 !reon1 a cross b> 7,e7 :i* is directly above ! magnets1 & s]ves z ! armature4 ,! re> end ( ! base has a screw 7,f7 directly b5ea? ! b> ,d ( su* height t :5 ! re> end ( ! b> ,d is 9 contact !re) ! armature ,e w be out ( contact ) ! magnet cores 7,a1 ,a74 ,a spiral spr+ 7,g7 secur$ to ! re> ends ( ! arm & to ! base1 respectively1 s]ves to keep ! re> end ( ! key normally 9 contact ) ! screw ,f4 ,,connect+ ,,up ,,! ,,key ,,& ,,s\nd]4--,hav+ made ^! two in/rum5ts1 we mu/ next connect !m up 9 ! circuit1 or circuits1 =m$ = !m1 z !re mu/ be a batt]y1 a key1 & a s\nd] at ea* end ( ! l9e4 ,9 ,fig4 #fi y w note two gr\ps ( ^? in/rum5ts4 ,n[ obs]ve h[ ! wires connect !m toge!r4 ,!re are two l9e wires1 "o 7,a7 :i* connects up ! two batt]ies1 ! wire be+ atta*$ s t "o end connects ) ! positive t]m9al ( ! batt]y1 & ! o!r end ) ! negative t]m9al4 ,illu/ration3 ,fig4 #fi4 ,a ,,telegraph ,,circuit ,! o!r l9e wire 7,b71 betwe5 ! two /ations1 has its opposite ends connect$ ) ! t]m9als ( ! electro-magnet ,c ( ! s\nd]s4 ,! o!r t]m9als ( ea* electro-magnet are connect$ up ) "o t]m9al ( ea* key by a wire 7,d71 & to complete ! circuit at ea* /ation1 ! o!r t]m9al ( ! key has a wire 7,e7 to its own batt]y4 ,,two ,,/ations ,,9 ,,circuit4--,! illu/ration %[s /ation #b telegraph+ to /ation #a4 ,?is is indicat$ by ! fact t ! swit* ,f' ( t in/rum5t is op51 & ! swit* ,f ( /ation #a clos$4 ,:51 !re=e1 ! key ( /ation #b is depress$1 a complete circuit is =m$ :i* transmits ! curr5t ?r\gh wire ,e' & batt]y1 ?r\gh l9e ,a1 !n ?r\gh ! batt]y ( /ation #a1 ?r\gh wire ,e to ! key1 & f ! key1 ?r\gh wire ,d1 to ! s\nd]1 & f9ally f ! s\nd] ov] l9e wire ,b back to ! s\nd] ( /ation #b1 complet+ ! circuit at ! key ?r\gh wire ,d'4 ,:5 ! op]ator at /ation #b closes ! swit* ,f'1 & ! op]ator at /ation #a op5s ! swit* ,f1 ! rev]se op]ation takes place4 ,9 bo? cases1 h[ev]1 ! s\nd] is 9 at bo? ends ( ! l9e1 & only ! circuit ?r\gh ! key is cut out by ! swit* ,f1 or ,f'4 ,,! ,,d\ble ,,click4--,! importance ( ! d\ble click ( ! s\nd] w be und]/ood :5 x is realiz$ t ! receiv+ op]ator mu/ h "s means ( det]m9+ if ! s\nd] has transmitt$ a dot or a da%4 ,:e!r he depresses ! key = a dot or a da%1 !re mu/ be "o click :5 ! key is press$ d[n on ! screw head ,g 7,fig4 #fb71 & also ano!r click1 ( a diff]5t k9d1 :5 ! key is rais$ up s t its re> end /rikes ! screw head ,j4 ,?is action ( ! key is in/antly duplicat$ by ! b> ,d 7,fig4 #fh7 ( ! s\nd]1 s t ! s\nd] z well z ! receiv] kn[s ! "t betwe5 ! fir/ & ! second click1 & by t means he le>ns t a dot or a da% is made4 ,,illu/rat+ ,,! ,,dot ,,& ,,! ,,da%4--,to illu/rate3 ,let u suppose1 = conv5i5ce1 t ! d[nw>d movem5t ( ! lev] 9 ! key1 & ! b> 9 ! s\nd]1 make a %>p click1 & ! return ( ! lev] & b> make a dull click4 ,9 ?is case ! e>1 aft] a little practice1 c le>n readily h[ to di/+ui% ! numb] ( d[nw>d impulses t h be5 giv5 to ! key4 ,! ,morse ,telegraph ,code ,a 4 - ,n - 4 4 444 ,b - 444 ,o 44 #a 4 - - 4 ,c 44 4 ,p 44444 #b 44 - 44 ,d - 4 4 ,q 44 - 4 #c 444 - 4 ,e 4 ,r 4 44 #d 4444 - ,f 4 - 4 ,s 444 #e - - - ,g - - 4 ,t - #f 444444 ,h 4444 ,u 44 - #g - - 44 ,i 44 ,v 444 - #h - 4444 ,j - 4 - 4 ,w 4 - - #i - 44 - ,k - 4 - ,x 4 - 44 #j ---- ------ ,l -- ,y 44 44 ,m - - ,z 444 4 ,,example ,,9 ,,use4--,let u take an example 9 ! ^w electrical4 ,e ,l ,e ,c ,t ,r ,i ,c ,a ,l 4 -- 4 44 4 - 4 44 44 44 4 4 - -- ,! op]ator fir/ makes a dot1 :i* means a %>p & a dull click close toge!r2 !re is !n a brief int]val1 !n a lapse1 aft] :i* !re is a %>p click1 foll[$1 aft] a comp>atively long] int]val1 ) ! dull click4 ,n[ a da% by itself may be an ,l1 a ,t1 or ! figure #j1 dep5d5t ^u its l5g?4 ,! %ort da% is ,t1 & ! longe/ da% ! figure #j4 ,! op]ator w soon le>n :e!r x is ei!r ( ^! or ! lett] ,l1 :i* is int]m$iate 9 l5g?4 ,9 "t ! s5d] z well z receiv] w give a uni=m l5g? to ! da% impulse1 s t x may be readily di/+ui%$4 ,9 ! same way1 we f9d t ,r1 :i* is indicat$ by a dot1 is foll[$1 aft] a %ort int]val1 by two dots4 ,?is might readily be mi/ak5 = ! s+le dot = ,e & ! two dots = ,i1 7 x n t ! "t elem5t 9 ,r is n z long betwe5 ! fir/ & second dots1 z x ord9>ily is betwe5 ! s+le dot ( ,e :5 foll[$ by ! two dots ( ,i4 ,,*apt] ,x ,,high ,,t5sion ,,app>atus1 ,,cond5s]s1 ,,etc4 ,,induction4--,"o ( ! mo/ rem>kable ?+s 9 electricity is ! action ( induction--t prop]ty ( an electric curr5t :i* enables x to pass f "o conductor to ano!r conductor ?r\gh ! air4 ,ano!r s+ul> & int]e/+ ?+ is t ! curr5t s transmitt$ across spaces *anges its direction ( fl[1 &1 fur!rmore1 ! t5sion ( su* a curr5t may be *ang$ by transmitt+ x f "o conductor to ano!r4 ,,l[ ,,& ,,high ,,t5sion4--,9 ord] to effect ?is latt] *ange--t is1 to conv]t x f a l[ t5sion to a high t5sion--coils are us$1 "o coil be+ w\nd ^u ! o!r2 "o ( ^! coils is call$ ! prim>y & ! o!r ! second>y4 ,! prim>y coil receives ! curr5t f ! batt]y1 or s\rce ( electrical p[]1 & ! second>y coil receives *>ges1 & transmits ! curr5t4 ,= an illu/ration ( ?is exam9e ,fig4 #gj1 9 :i* y w note a coil ( heavy wire 7,a71 ar\nd :i* is w\nd a coil ( f9e wire 7,b74 ,if1 = in/ance1 ! prim>y coil has a l[ voltage1 ! second>y coil w h a high voltage1 or t5sion4 ,advantage is tak5 ( ?is phase to use a few cells1 z a prim>y batt]y1 & !n1 by a set ( ,induction ,coils1 z !y are call$1 to build up a high-t5sion electro-motive =ce1 s t ! sp>k w jump across a gap1 z %[n at ,c1 = ! purpose ( ignit+ ! *>ges ( gas 9 a gasol9e motor2 or ! curr5t may be us$ = m$ical batt]ies1 & = o!r purposes4 ,illu/ration3 ,fig4 #gj4 ,,induction ,,coil ,,& ,,circuit ,! curr5t passes1 by induction1 f ! prim>y to ! second>y coil4 ,x passes f a l>ge conductor to a small conductor1 ! small conductor hav+ a mu* great] resi/ance ?an ! l>ge "o4 ,,ela/ic ,,prop]ty ,,( ,,electricity4--,:ile electricity has no resili5cy1 l a spr+1 = in/ance1 /ill x acts 9 ! mann] ( a cu%ion "u c]ta9 conditions4 ,x may be lik5$ to an oscillat+ spr+ act$ ^u by a b>4 ,ref]r+ to ,fig4 #ga1 we w assume t ! b> ,a 9 fall+ d[n ^u ! spr+ ,b compresses ! latt]1 s t at ! "t ( greate/ compression ! b> goes d[n z f> z ! dott$ l9e ,c4 ,x is obvi\s t ! spr+ ,b w ?r[ ! b> upw>dly4 ,n[1 electricity appe>s to h a k9d ( ela/icity1 :i* *>act]i/ic is tak5 advantage ( 9 ord] to increase ! effici5cy ( ! induction 9 ! coil4 ,illu/ration3 ,fig4 #ga4 ,,illu/rat+ ,,ela/icity ,,! ,,cond5s]4--,to make a cond5s]1 prep>e two p9e bo>ds l ,a1 say1 eight by t5 in*es & a half in* ?ick1 & %ellac ?or\ghly on all sides4 ,!n prep>e %eets ( t9foil 7,b71 six by eight in*es 9 size1 & also %eets ( p>aff9$ pap] 7,c71 sev5 by n9e in*es 9 dim5sions4 ,also cut out f ! wa/e pieces ( t9foil /rips 7,d71 "o in* by two in*es4 ,to build up ! cond5s]1 lay d[n a %eet ( p>aff9$ pap] 7,c71 !n a %eet ( t9foil 7,b71 & be=e putt+ on ! next %eet ( p>aff9$ pap] lay d[n "o ( ! small /rips 7,d7 ( t9foil1 z %[n 9 ! illu/ration1 s t its end projects ov] "o end ( ! bo>d ,a2 !n on ! second %eet ( p>aff9e pap] lay ano!r %eet ( t9foil1 & on ?is1 at ! opposite end1 place "o ( ! small /rips 7,d71 & s on1 us+ f #ej to #ajj ( ! t9foil %eets4 ,:5 ! la/ p>aff9e %eet is laid on1 ! o!r bo>d is plac$ on top1 & ! :ole b\nd toge!r1 ei!r by wrapp+ cords ar\nd ! same or by clamp+ !m toge!r ) bolts4 ,illu/ration3 ,fig4 #gb4 ,,cond5s] ,y may n[ make a hole ?r\gh ! project+ ends ( ! /rips1 & y w h two sets ( t9foil %eets1 alt]nately connect$ toge!r at opposite ends ( ! cond5s]4 ,c>e %\ld be ex]cis$ to leave ! p>aff9e %eets p]fect or )\t holes4 ,y c make ^! %eets y\rself by soak+ !m 9 melt$ p>aff9e wax4 ,,connect+ ,,up ,a ,,cond5s]4--,:5 complet$1 "o end ( ! cond5s] is connect$ up ) "o t]m9al ( ! second>y coil1 & ! o!r end ( ! cond5s] ) ! o!r second>y t]m9al4 ,illu/ration3 ,fig4 #gc4 ,,high-,,t5sion ,,circuit ,9 ,fig4 #gc a high-t5sion circuit is %[n4 ,two coils1 side by side1 are always us$ to %[ an induction coil1 & a cond5s] is g5]ally %[n1 z illu/rat$1 by means ( a pair ( =ks1 "o re/+ )9 ! o!r4 ,,! ,,int]rupt]4--,"o o!r piece ( me*anism is necess>y1 & t is an ,int]rupt]1 = ! purpose ( gett+ ! effect ( ! pulsations giv5 out by ! second>y coil4 ,a simple curr5t int]rupt] is made z foll[s3 ,prep>e a wood5 base 7,a71 "o in* ?ick1 six in*es wide1 & twelve in*es long4 ,^u ?is m\nt a too!d :eel 7,b71 six in*es 9 diamet]1 ( ?9 %eet metal1 or a brass ge> :eel w answ] ! purpose4 ,! /&>d 7,c71 :i* supports ! :eel1 may be ( metal b5t up to =m two po/s1 betwe5 :i* ! crank%aft 7,d7 is j\rnal$4 ,! base ( ! po/s has an ext5sion plate 7,e71 ) a b9d+ po/ = a wire4 ,at ! front end ( ! base is an ,l-%ap$ /rip 7,f71 ) a b9d+ po/ = a wire connection1 & ! upw>dly project+ "p ( ! /rip contacts ) ! too!d :eel4 ,:5 ! :eel ,b is rotat$ ! spr+ f+] 7,f7 snaps f "o too? to ! next1 s t1 mom5t>ily1 ! curr5t is brok51 & ! frequ5cy is dep5d5t ^u ! spe$ imp>t$ to ! :eel4 ,illu/ration3 ,fig4 #gd4 ,,curr5t ,,int]rupt] ,,uses ,,( ,,high-,,t5sion ,,coils4--,?is high-t5sion coil is made use (1 & is ! ess5tial app>atus 9 wireless telegraphy1 z we %all see 9 ! *apt] treat+ ^u t subject4 ,,*apt] ,,xi ,,wireless ,,telegraphy ,,telegraph+ ,,)\t ,,wires4--,wireless telegraphy is an outgr[? ( ! ord9>y telegraph sy/em4 ,:5 ,maxwell1 &1 lat] on1 ,h]tz1 discov]$ t electricity1 magnetism1 & light 7 transmitt$ ?r\gh ! e!r1 & t !y diff]$ only 9 _! wave l5g?s1 !y laid ! f\ndations = wireless telegraphy4 ,e!r is a sub/ance :i* is millions & millions ( times light] ?an air1 & x p]vades all space4 ,x is s un/able t x is con/antly 9 motion1 & ?is phase l$ "s "o to sugge/ t if a prop] electrical app>atus c\ld be made1 ! e!r w\ld !reby be di/urb$ suffici5tly s t its impulses w\ld ext5d out a di/ance proportion$ to ! int5sity ( ! electrical agitation !reby creat$4 ,,surg+ ,,"* ,,( ,,high-,,t5sion ,,curr5ts4--,:5 a curr5t ( electricity is s5t ?r\gh a wire1 hundr$s ( miles 9 l5g?1 ! curr5t surges back & =? on ! wire _m ?\s&s ( times a second4 ,light comes to u f ! sun1 ov] #ij1jjj1jjj ( miles1 ?r\gh ! e!r4 ,x is z reasonable to suppose1 or inf]1 t ! e!r c1 !re=e1 convey an electrical impulse z readily z does a wire4 ,x is on ?is pr9ciple t impulses are s5t = ?\s&s ( miles1 & no d\bt !y ext5d ev5 f>!r1 if ! prop] me*anism c\ld be devis$ to detect movem5t ( ! waves s propagat$4 ,,! ,,coh]]4--,! in/rum5t = detect+ ^! impulses1 or di/urbances1 9 ! e!r is g5]ally call$ a coh]]1 al?\gh detector is ! t]m :i* is mo/ satisfactory4 ,! "n coh]] comes f ! fir/ practical in/rum5t made = ?is purpose4 ,illu/ration3 ,fig4 #ge4 ,,wireless ,,telegraphy ,,coh]] ,,h[ ,,made4--,! coh]] is simply a tube1 say1 ( glass1 )9 :i* is plac$ iron fil+s4 ,:5 ! oscillations surge ?r\gh ! second>y coil ! pressure or pot5tiality ( ! curr5t f9ally causes x to leap across ! small space sep>at+ ! fil+s &1 z x 71 x welds toge!r _! edges s t a curr5t freely passes4 ,! br++ toge!r ( ! p>ticles1 "u ^! conditions1 is call$ coh]+4 ,fig4 #ge %[s ! simple/ =m ( coh]]4 ,! po/s 7,a7 are firmly affix$ to ! base 7,b71 ea* po/ hav+ an adju/+ screw 7,c7 9 its upp] end1 & ^! screw d[nw>dly aga9/ & s]ve to b9d a pair ( horizontal rods 7,d71 ! inn] ends ( :i* closely approa* ea* o!r4 ,^! may be adju/$ s z to be z ne> toge!r or z f> ap>t z desir$4 ,e is a glass tube 9 :i* ! ends ( ! rods 7,d7 re/1 & betwe5 ! sep>at$ ends ( ! rods 7,d7 ! iron fil+s 7,f7 are plac$4 ,,! ,,decoh]]s4--,= ! purpose ( caus+ ! metal fil+s to fall ap>t1 or decoh]e1 ! tube is tapp$ lightly1 & ?is is done by a little object l ! clapp] ( an electric bell4 ,9 practice1 ! coils & ! p>ts directly connect$ ) x are put toge!r on "o base4 ,,! ,,s5d+ ,,app>atus4--,fig4 #gf %[s a section ( a coil ) its connection 9 ! s5d+ /ation4 ,! sp>k gap rods 7,a7 may be swung s z to br+ !m clos] toge!r or f>!r ap>t1 b !y mu/ n at any "t contact ) ea* o!r4 ,! induction coil has "o t]m9al ( ! prim>y coil connect$ up by a wire 7,b7 ) "o po/ ( a telegraph key1 & ! o!r po/ ( ! key has a wire connection 7,c71 ) "o side ( a /orage batt]y4 ,! o!r side ( ! batt]y has a wire 7,d7 runn+ to ! o!r t]m9al ( ! prim>y4 ,illu/ration3 ,fig4 #gf4 ,,wireless ,,s5d+ ,,app>atus ,! second>y coil has "o ( its t]m9als connect$ ) a b9d+ po/ 7,e74 ,?is b9d+ po/ has an adju/able rod ) a knob 7,f7 on its end1 & ! o!r b9d+ po/ 7,g71 :i* is connect$ up ) ! o!r t]m9al ( ! second>y coil1 c>ries a simil> adju/+ rod ) a knob 7,h74 ,f ! po/ 7,e7 is a wire 7,i71 :i* ext5ds upw>dly1 & is call$ ! a]ial wire1 or wire = ! ant5n1 & ?is wire also connects ) "o side ( ! cond5s] by a conductor 7,j74 ,! gr\nd wire 7,k7 connects ) ! o!r b9d+ po/ 7,g71 & a bran* wire 7,l7 also connects ! gr\nd wire 7,k7 ) "o end ( ! cond5s]4 ,illu/ration3 ,fig4 #gg4 ,,wireless ,,receiv+ ,,app>atus ,,! ,,receiv+ ,,app>atus4--,! receiv+ /ation1 on ! o!r h&1 has nei!r cond5s]1 induction coil1 nor key4 ,:5 ! app>atus is 9 op]ation1 ! coh]] swit* is clos$1 & ! in/ant a curr5t passes ?r\gh ! coh]] & op]ates ! telegraph s\nd]1 ! galvanomet] indicates ! curr5t4 ,( c\rse1 :5 ! coh]] swit* is clos$1 ! batt]y op]ates ! decoh]]4 ,,h[ ,,! ,,circuits ,,are ,,=m$4--,by ref]r+ aga9 to ,fig4 #gf1 x w be se5 t :5 ! key is depress$1 a circuit is =m$ f ! batt]y ?r\gh wire ,b to ! prim>y coil1 & back aga9 to ! batt]y ?r\gh wire ,d4 ,! second>y coil is !reby en]giz$1 &1 :5 ! full pot5tial is rea*$1 ! curr5t leaps across ! gap =m$ betwe5 ! two knobs 7,f1 ,h71 !reby sett+ up a di/urbance 9 ! e!r :i* is transmitt$ ?r\gh space 9 all directions4 ,x is ?is impulse1 or di/urbance1 :i* is receiv$ by ! coh]] at ! receiv+ /ation1 & :i* is indicat$ by ! telegraph s\nd]4 ,,*apt] ,,xii ,,! ,,telephone ,,vibrations4--,e manife/ation 9 nature is by way ( vibration4 ,! beat+ ( ! he>t1 ! action ( ! legs 9 walk+1 ! w9k+ ( ! eyelid2 ! impulses f ! sun1 :i* we call light2 s\nd1 ta/e & color appeal to our s5ses by vibratory means1 &1 z we h h]e9be=e /at$1 ! manife/ations ( electricity & magnetism are m]ely vibrations ( diff]5t wave l5g?s4 ,,! ,,ac\/ic ,,telephone4--,t s\nd is m]ely a product ( vibrations may be prov5 9 _m ways4 ,"o ( ! e>lie/ =ms ( telephones 0 simply a s\nd telephone1 call$ ! ,ac\/ic ,telephone4 ,! pr9ciple ( ?is may be illu/rat$ z foll[s3 ,take two cups 7,a1 ,b71 z 9 ,fig4 #gh1 pun* a small hole ?r\gh ! bottom ( ea*1 & run a /r+ or wire 7,c7 f ! hole ( "o cup to t ( ! o!r1 & secure x at bo? ends s x may be drawn taut4 ,n[1 by talk+ into ! cup 7,a7 ! bottom ( x w vibrate to & fro1 z %[n by ! dott$ l9es & !reby cause ! bottom ( ! o!r cup 7,b7 to vibrate 9 l mann]1 & 9 s vibrat+ x w receive n only ! same amplitude1 b also ! same "* ( vibrations z ! cup 7,a7 gave =?4 ,illu/ration3 ,fig4 #gh4 ,,ac\/ic ,,telephone ,illu/ration3 ,fig4 #gi4 ,,illu/rat+ ,,vibrations ,,s\nd ,,waves4--,s\nd waves are long & %ort2 ! long waves giv+ s\nds :i* are l[ 9 ! musical scale1 & ! %ort waves high musical tones4 ,y may easily det]m9e ?is by ! foll[+ exp]im5t3 ,/ret* a wire1 z at ,b 7,fig4 #gi71 fairly tight1 & !n vibrate x4 ,! amplitude ( ! vibration w be z indicat$ by dott$ l9e ,a4 ,n[1 /ret* x v tight1 z at ,c1 s t ! amplitude ( vibration w be z %[n at ,e4 ,by putt+ y\r e> close to ! /r+ y w f9d t :ile ,a has a l[ pit*1 ,c is v mu* high]4 ,?is is ! pr9ciple on :i* /r+$ in/rum5ts are built4 ,y w note t ! wave l5g?1 :i* repres5ts ! di/ance betwe5 ! dott$ l9es ,a is mu* great] ?an ,e4 ,,he>+ ,,electricity4--,9 electricity1 me*anism has be5 made to enable man to note ! action ( ! curr5t4 ,by means ( ! armature1 vibrat+ 9 front ( a magnet1 we c see its manife/ations4 ,x is n[ b a /ep to devise "s means :]eby we may he> x4 ,9 ?is1 z 9 ev]y?+ else electrically1 ! magnet comes into play4 ,illu/ration3 ,fig4 #hj4 ,,! ,,magnetic ,,field ,9 ! *apt] on magnetism1 x 0 /at$ t ! magnetic field ext5d$ out beyond ! magnet1 s t if we 7 able to see ! magnetism1 ! end ( a magnet w\ld appe> to u some?+ l a mov+ field1 repres5t$ by ! dott$ l9es 9 ,fig4 #hj4 ,! magnetic field is %[n 9 ,fig4 #hj at only "o end1 b its manife/ations are alike at bo? ends4 ,x w be se5 t ! magnetic field ext5ds out to a consid]able di/ance & has q a radius ( influ5ce4 ,,! ,,diaphragm ,,9 ,a ,,magnetic ,,field4--,if1 n[1 we put a diaphragm 7,a7 9 ?is magnetic field1 close up to ! end ( ! magnet1 b n s close z to t\* x1 & !n pu% x 9 & out1 or talk into x s t ! s\nd waves /rike x1 ! movem5t or ! vibration ( ! diaphragm 7,a7 w di/urb ! magnetic field emanat+ f ! magnet1 & ?is di/urbance ( ! magnetic field at "o end ( ! magnet also affects ! magnetic field at ! o!r end 9 ! same way1 s t ! di/urbance !re w be ( ! same amplitude4 ,x w also display ! same *>act]i/ics z did ! magnetic field :5 ! diaphragm 7,a7 di/urb$ x4 ,a ,,simple ,,telephone ,,circuit4--,f ?is simple fact grew ! telephone4 ,if two magnets are connect$ up 9 ! same circuit1 s t ! magnetic fields ( ! two magnets h ! same s\rce ( electric p[]1 ! di/urbance ( "o diaphragm w affect ! o!r simil>ly1 j ! same z ! two magnetic fields ( ! s+le magnet are di/urb$ 9 unison4 ,,h[ ,,to ,,make ,a ,,telephone4--,= exp]im5tal & te/+ purposes two ( ^! telephones %\ld be made at ! same "t4 ,! case or hold] 7,a7 may be made ei!r ( h>d wood or h>d rubb]1 s t x is ( insulat+ mat]ial4 ,! core 7,b7 is ( s(t iron1 #c_/h in* 9 diamet] & #e in*es long1 bor$ & ?read$ at "o end to receive a screw 7,c7 :i* passes ?r\gh ! end ( ! case 7,a74 ,! enl>g$ end ( ! case %\ld be1 ext]iorly1 #b-a_/d in*es 9 diamet]1 & ! body ( ! case #a in* 9 diamet]4 ,illu/ration3 ,fig4 #ha4 ,,section ,,( ,,telephone ,,receiv] ,int]iorly1 ! l>ge end ( ! case is provid$ ) a circul> recess #a-c_/d in*es 9 diamet] & adapt$ to receive !re9 a spool :i* is1 diametrically1 a little small] ?an ! recess4 ,! spool fits fairly tight ^u ! end ( ! core1 & :5 9 position re/s aga9/ an annul> %\ld] 9 ! recess4 ,a holl[ space 7,f7 is ?us provid$ beh9d ! spool 7,d71 s ! two wires f ! magnet may h room :]e !y em]ge f ! spool4 ,! spool is a little %ort] ?an ! di/ance betwe5 ! %\ld] 7,e7 & ! end ( ! cas+1 at ,g1 & ! core projects only a %ort di/ance beyond ! end ( ! spool1 s t :5 ! diaphragm 7,h7 is put ^u ! end ( ! case1 & held !re by screws 7,i7 x w n t\* ! end ( ! core4 ,a wood5 or rubb] m\?piece 7,j7 is !n turn$ up to fit ov] ! end ( ! case4 ,illu/ration3 ,fig4 #hb4 ,,! ,,magnet ,,& ,,receiv] ,,head ,! spool 7,d7 is made ( h>d rubb]1 & is w\nd ) ,no4 #bd silk-cov]$ wire1 ! w9d+s to be well insulat$ f ea* o!r4 ,! two ends ( ! wire are br\ght out1 & ?read$ ?r\gh holes 7,k7 drill$ longitud9ally ?r\gh ! walls ( ! case1 & affix$ to ! end by means ( screws 7,l71 s t ! two wires may be br\ght toge!r & connect$ ) a duplex wire 7,m74 ,z ! screw 7,c71 :i* holds ! core 9 place1 has its head hidd5 )9 a recess1 :i* c be clos$ up by wax1 ! two t]m9als ( ! wires are well sep>at$ s t %ort-circuit+ _c take place4 ,,telephone ,,connections4--,! simple/ =m ( telephone connection is %[n 9 ,fig4 #hc4 ,?is has m]ely ! two telephones 7,a & ,b71 ) a s+le batt]y 7,c7 to supply electricity = bo?4 ,"o l9e wire 7,d7 connects ! two telephones directly1 :ile ! o!r l9e 7,e7 has ! batt]y 9 its circuit4 ,illu/ration3 ,fig4 #hc4 ,,simple ,,telephone ,,connection ,,complete ,,in/allation4--,to in/all a m complete sy/em requires1 at ea* end1 a swit*1 a batt]y & an electro-magneto bell4 ,y may use1 = ?is purpose1 a bell1 made z %[n 9 ! *apt] on bells4 ,fig4 #hd %[s su* a circuit4 ,we n[ disp5se ) "o ( ! l9e wires1 because x has be5 f\nd t ! gr\nd betwe5 ! two /ations s]ves z a conductor1 s t only "o l9e wire 7,a7 is necess>y to connect directly ) ! telephones ( ! two /ations4 ,! telephones 7,b1 ,b'1 respectively7 h wires 7,c1 ,c'7 runn+ to ! pivots ( d\ble-?r[ swit*es 7,d1 ,d'71 "o t]m9al ( ! swit*es hav+ wires 7,e1 ,e'71 :i* g to electric bells 7,f1 ,f'71 & f ! bells are o!r wires 7,g1 ,g'71 :i* g to ! gr\nd4 ,! gr\nd wires also h wires 7,h1 ,h'71 :i* g to ! o!r t]m9als ( ! swit* 7,d1 ,d'74 ,! d\ble-?r[ swit* 7,d1 ,d'71 9 ! two /ations1 is ?r[n ov] s ! curr5t1 if any %\ld pass ?r\gh1 w g ?r\gh ! bell to ! gr\nd1 ?r\gh ! wires 7,e1 ,g or ,e'1 ,g'74 ,illu/ration3 ,fig4 #hd4 ,,telephone ,,/ations ,,9 ,,circuit ,n[1 suppos+ ! swit* 7,d'71 9 /ation #b1 %\ld be ?r[n ov] s x contacts ) ! wire 7,h'74 ,x is obvi\s t ! curr5t w !n fl[ f ! batt]y 7,i'7 ?r\gh wires 7,h'1 ,c'7 & l9e 7,a7 to /ation #a2 !n ?r\gh wire ,c1 swit* ,d1 wire ,e to ! bell ,f1 to ! gr\nd ?r\gh wire ,g4 ,f wire ,g ! curr5t returns ?r\gh ! gr\nd to /ation #b1 :]e x fl[s up wire ,g' to ! batt]y1 !reby complet+ ! circuit4 ,illu/ration3 ,fig4 #he4 ,,illu/rat+ ,,light ,,contact ,,po9ts ,! op]ator at /ation #b1 hav+ giv5 ! signal1 aga9 ?r[s 8 swit* 7,d'7 back to ! position %[n 9 ,fig4 #hd1 & ! op]ator at /ation #a ?r[s on 8 swit* 7,d71 s z to r+ ! bell 9 /ation #b1 !reby answ]+ ! signal1 :i* means t bo? swit*es are aga9 to be ?r[n ov] s !y contact ) ! batt]y wires 7,h & ,h'71 respectively4 ,:5 bo? are ?us ?r[n ov]1 ! bells 7,g1 ,g'7 are cut out ( ! circuit1 & ! batt]ies are bo? ?r[n 91 s t ! telephones are n[ ready = talk+ purposes4 ,,microphone4--,orig9ally ?is =m ( telephone sy/em 0 g5]ally employ$1 b x 0 f\nd t = long di/ances a m s5sitive in/rum5t 0 necess>y4 ,,light ,,contact ,,po9ts4--,9 #ahgg ,pr(essor ,hughes discov]$1 accid5tally1 t a light contact po9t 9 an electric circuit augm5t$ ! s\nd 9 a telephone circuit4 ,if1 = in/ance1 a light p91 or a nail 7,a1 ,fig4 #he7 %\ld be us$ to connect ! sev]$ ends ( a wire 7,b71 ! s\nds 9 ! telephone n only w\ld be l\d]1 b !y w\ld be m di/9ct1 & ! fir/ in/rum5t made practically1 to demon/rate ?is1 is %[n 9 ,fig4 #hf4 ,illu/ration3 ,fig4 #hf4 ,,microphone ,illu/ration3 ,fig4 #hg4 ,,transmitt] ,,h[ ,,to ,,make ,a ,,microphone4--,?is in/rum5t has simply a base 7,a7 ( wood1 & ne> "o end is a p]p5dicul> s\nd+-bo>d 7,b7 ( wood1 to "o side ( :i* is atta*$1 by wax or o!rwise1 a pair ( c>bon blocks 7,c1 ,d74 ,! l[] c>bon block 7,c7 has a cup-%ap$ depression 9 its upp] side1 & ! upp] block has a simil> depression 9 its l[] side4 ,a c>bon p5cil 7,e7 is lightly held )9 ^! cups1 s t ! lighte/ contact ( ! upp] end ( ! p5cil ) ! c>bon block1 makes ! in/rum5t s s5sitive t a fly1 walk+ ^u ! s\nd+-bo>d1 may be di/9ctly he>d ?r\gh ! telephone :i* is 9 ! circuit4 ,,microphone ,,! ,,fa!r ,,( ,,! ,,transmitt]4--,?is in/rum5t has be5 greatly modifi$1 & is n[ us$ z a transmitt]1 ! latt] !reby tak+ ! place ( ! p9 7,a71 %[n 9 ,fig4 #he4 ,,automatic ,,cut-,,outs ,,= ,,telephones4--,9 ! op]ation ( ! telephone1 ! great drawback orig9ally 0 9 induc+ us]s ( ! l9es to replace or adju/ _! in/rum5ts c>efully4 ,:5 swit*es 7 us$1 !y w\ld =get to ?r[ !m back1 & all sorts ( tr\ble result$4 ,x 0 f\nd necess>y to provide an automatic means = ?r[+ 9 & cutt+ out an in/rum5t1 ?is be+ done by hang+ ! telephone on ! hook1 s t ! act m]ely ( leav+ ! telephone made x necess>y1 9 replac+ ! in/rum5t1 to cut out ! app>atus4 ,be=e describ+ ! circuit+ requir$ = ^! improvem5ts1 we %[1 9 ,fig4 #hg1 a section ( a transmitt]4 ,a cup-%ap$ case 7,a7 is provid$1 made ( "s insulat+ mat]ial1 :i* has a diaphragm 7,b7 secur$ at its op5 side4 ,?is diaphragm c>ries ! c>bon p5cil 7,c7 on "o side & f ! blocks :i* support ! c>bon p5cil ! wires run to b9d+ po/s on ! case4 ,( c\rse ! c>bon support+ po/s mu/ be insulat$ f ea* o!r1 s ! curr5t w g ?r\gh ! c>bon p5cil 7,c74 ,,complete ,,circuit+ ,,) ,,transmitt]4--,9 %[+ ! circuit+ 7,fig4 #hh7 x w n be possible to illu/rate ! boxes1 or cas+s1 :i* receive ! v>i\s in/rum5ts4 ,= in/ance1 ! hook :i* c>ries ! telephone or ! receiv]1 is h+$ )9 ! transmitt] box4 ,! circuit+ is all t x is int5d$ to %[4 ,illu/ration3 ,fig4 #hh4 ,,complete ,,telephonic ,,circuit ,! batt]ies ( ! two /ations are connect$ up by a wire 7,a71 unless a gr\nd circuit is us$4 ,! o!r side ( ea* batt]y has a wire connection 7,b1 ,b'7 ) "o t]m9al ( ! transmitt]1 & ! o!r t]m9al ( ! transmitt] has a wire 7,c1 ,c'7 :i* goes to ! receiv]4 ,f ! o!r t]m9al ( ! receiv] is a wire 7,d1 ,d'7 :i* leads to ! upp] /op contact 7,e1 ,e'7 ( ! telephone hook4 ,a wire 7,f1 ,f'7 f ! l[] /op contact 7,g1 ,g'7 ( ! hook goes to "o t]m9al ( ! bell1 & f ! o!r t]m9al ( ! bell is a wire 7,h1 ,h'7 :i* makes connection ) ! l9e wire 7,a74 ,9 ord] to make a complete circuit betwe5 ! two /ations1 a l9e wire 7,i7 is run f ! pivot ( ! hook 9 /ation #a to ! pivot ( ! hook 9 /ation #b4 ,9 ! diagram1 x is assum$ t ! receiv]s are on ! hooks1 & t bo? hooks are1 !re=e1 9 circuit ) ! l[] contacts 7,g1 ,g'71 s t ! transmitt] & receiv] are bo? out ( circuit ) ! batt]ies1 & ! bell 9 circuit2 b ! mom5t ! receiv]1 = in/ance1 9 /ation #a is tak5 (f ! hook1 ! latt] spr+s up s t x contacts ) ! /op 7,e71 ?us e/abli%+ a circuit ?r\gh ! l9e wire 7,i7 to ! hook ( /ation #b1 & f ! hook ?r\gh l9e 7,f'7 to ! bell4 ,f ! bell1 ! l9e 7,a7 c>ries ! curr5t back to ! batt]y ( /ation 7,a71 !nce ?r\gh ! wire 7,b7 to ! transmitt] wire 7,c7 to receiv] & wire 7,d7 to ! po/ 7,e71 !reby complet+ ! circuit4 ,:51 at /ation #b1 ! receiv] is tak5 (f ! hook1 & ! latt] contacts ) ! po/ 7,e'71 ! transmitt] & receiv] ( bo? /ations are 9 circuit ) ea* o!r1 b bo? bells are cut out4 ,,*apt] ,,xiii ,,electrolysis1 ,,wat] ,,purification1 ,,electroplat+ ,,decompos+ ,,liquids4--,dur+ ! e>li] exp]im5ts 9 ! field ( electricity1 aft] ! batt]y or cell 0 discov]$1 x 0 not$ t :5 a curr5t 0 =m$ 9 ! cell1 ! electrolyte 0 *>g$ & gases evolv$ f x4 ,a simil> action takes place :5 a curr5t ( electricity passes ?r\gh a liquid1 ) ! result t ! liquid is decompos$--t is1 ! liquid is brok5 up into its orig9al comp\nds4 ,?us1 wat] is compos$ ( two p>ts1 by bulk1 ( hydrog5 & ( oxyg51 s t if two electrodes are plac$ 9 wat]1 & a curr5t is s5t ?r\gh ! electrodes 9 ei!r direction1 all ! wat] w f9ally disappe> 9 ! =m ( hydrog5 & oxyg5 gases4 ,,mak+ ,,hydrog5 ,,& ,,oxyg54--,dur+ ?is electrical action1 ! hydrog5 is set free at ! negative pole & ! oxyg5 at ! positive pole4 ,a simple app>atus1 :i* any boy c make1 to g5]ate pure oxyg5 & pure hydrog51 is %[n 9 ,fig4 #hi4 ,x is con/ruct$ ( a glass or e>!n j> 7,a71 pref]ably squ>e1 to :i* is fitt$ a wood5 top 7,b71 ?is top be+ provid$ ) a pack+ r+ 7,c71 s z to make x air-tight4 ,)9 is a v]tical p>tition 7,d71 ! edges ( :i*1 bel[ ! cap1 fit tightly aga9/ ! inn] walls ( ! j>4 ,?is p>tition ext5ds d[n into ! j> a suffici5t di/ance s x w t]m9ate bel[ ! wat] level4 ,a pipe is fitt$ ?r\gh ! top on ea* side ( ! p>tition1 & ea* pipe has a valve4 ,an electrode1 ( any conv5i5t metal1 is secur$ at its upp] end to ! top ( ! cap1 on ea* side ( ! p>tition4 ,^! electrodes ext5d d[n to ! bottom ( ! j>1 & an electric wire connects ) ea* ( !m at ! top4 ,illu/ration3 ,fig4 #hi4 ,,device ,,= ,,mak+ ,,hydrog5 ,,& ,,oxyg5 ,if a curr5t ( electricity is pass$ ?r\gh ! wires & ! electrodes1 9 ! direction %[n by ! d>ts1 hydrog5 w =m at ! negative pole1 & oxyg5 at ! positive pole4 ,^! gases w escape upw>dly1 s t !y w be trapp$ 9 _! respective comp>tm5ts1 & may be drawn (f by means ( ! pipes4 ,,purify+ ,,wat]4--,advantage is tak5 ( ?is electrolytic action1 to purify wat]4 ,oxyg5 is ! mo/ wond]ful *emical 9 nature4 ,x is call$ ! acid-mak] ( ! univ]se4 ,! "n is d]iv$ f two words1 oxy & g52 "o d5ot+ oxydation1 & ! o!r t x g5]ates4 ,9 o!r words1 x is ! g5]ator ( oxides4 ,x is ! elem5t :i*1 :5 unit$ ) any o!r elem5t1 produces an acid1 an alkali or a neutral comp\nd4 ,,ru/4--,= in/ance1 iron is l>gely compos$ ( f]ric acid4 ,:5 oxyg51 9 a free or gase\s /ate1 comes into contact ) iron1 x produces f]r\s oxide1 :i* is recogniz$ z ru/4 ,,oxyg5 ,,z ,a ,,purifi]4--,b oxyg5 is also a purifi]4 ,all l[ =ms ( animal life1 l bact]ia or g]ms 9 wat]1 succumb to free oxyg54 ,by free oxyg5 is meant oxyg5 9 ! =m ( gas4 ,,composition ,,( ,,wat]4--,n[1 wat]1 9 :i* h>mful g]ms live1 is "o-?ird oxyg54 ,nev]!less1 ! g]ms ?rive 9 wat]1 because ! oxyg5 is 9 a comp\nd /ate1 &1 !re=e1 n an active ag5t4 ,b if oxyg51 9 ! =m ( gas1 c be =c$ ?r\gh wat]1 x w attack ! g]ms1 & de/roy !m4 ,,common ,,air ,,n ,a ,,good ,,purifi]4--,wat] may be purifi$1 to a c]ta9 ext5t1 by =c+ common air ?r\gh x1 & ! f\le/ wat]1 if run ov] rocks1 w be purifi$1 9 a measure1 because air is int]m+l$ ) x4 ,b common air is compos$ ( f\r-fif?s nitrog51 & only "o-fif? oxyg51 &1 z nitrog5 is ! /aple article ( food = bact]ia1 ! purify+ me?od by air is n effectual4 ,,pure ,,oxyg54--,:51 h[ev]1 oxyg5 is g5]at$ f wat]1 by means ( electrolysis1 x is pure2 h5ce is m active & is n ta9t$ by a life-giv+ sub/ance = g]ms1 su* z nitrog54 ,! me*anism usually employ$ = purify+ wat] is %[n 9 ,fig4 #ij4 ,a ,,wat] ,,purifi]4--,! case 7,a1 ,fig4 #ij7 may be made ( metal or ( an insulat+ mat]ial4 ,if made ( metal x mu/ be insulat$ )9 ) slate1 glass1 m>ble or h>d rubb]1 z %[n at ,b4 ,! case is provid$ ) ext]ior flanges 7,c1 ,d71 ) upp] & l[] ends1 & x is m\nt$ ^u a base plate 7,e7 & affix$ !reto by bolts4 ,! upp] end has a conically-=m$ cap 7,f7 bolt$ to ! flanges 7,c71 & ?is has an outlet to :i* a pipe 7,g7 is atta*$4 ,! wat] inlet pipe 7,h7 passes ?r\gh ! l[] end ( ! case 7,a74 ,! electrodes 7,i1 ,j7 are secur$1 v]tically1 )9 ! case1 sep>at$ f ea* o!r equidi/ant1 ea* alt]nate electrode be+ connect$ up ) "o wire 7,k71 & ! alt]nate electrodes ) a wire 7,l74 ,illu/ration3 ,fig4 #ij4 ,,electric ,,wat] ,,purifi] ,:5 ! wat] passes upw>dly1 ! decompos$ or gase\s oxyg5 p]colates ?r\gh ! wat] & ?us attacks ! g]ms & de/roys !m4 ,,! ,,use ,,( ,,hydrog5 ,,9 ,,purification4--,on ! o!r h&1 ! hydrog5 also plays an important "p 9 purify+ ! wat]4 ,?is dep5ds ^u ! mat]ial ( :i* ! electrodes are made4 ,alum9um is by f> ! be/ mat]ial1 z x is "o ( nature's mo/ active purifi]s4 ,all clay conta9s alum9um1 9 :at is kn[n z ! sulphate =m1 & wat] pass+ ?r\gh ! clay ( ! e>? !reby becomes purifi$1 because ( ?is elem5t4 ,,alum9um ,,electrodes4--,:5 ?is mat]ial is us$ z ! electrodes 9 wat]1 hydrate ( alum9um is =m$1 or a comp\nd ( hydrog5 & oxyg5 ) alum9um4 ,! product ( decomposition is a floccul5t matt] :i* moves upw>dly ?r\gh ! wat]1 giv+ x a milky appe>ance4 ,?is sub/ance is l gelat9e1 s t x entangles or enme%es ! g]m life & prev5ts x f pass+ ?r\gh a filt]4 ,if no filt] is us$1 ?is floccul5t matt]1 z soon z x has giv5 (f ! gases1 w settle to ! bottom & c>ry ) x all decompos$ matt]1 su* z g]ms & o!r organic matt] attack$ by ! oxyg51 :i* has become entangl$ 9 ! alum9um hydrate4 ,,electric ,,h& ,,purifi]4--,an int]e/+ & s]viceable little purifi] may be made by any boy ) ! simple/ tools1 by cutt+ out ?ree pieces ( %eet alum9um4 ,h>d roll$ is be/ = ! purpose4 ,x is bett] to h "o ( ! %eets 7,a71 ! middle "o1 ?ick] ?an ! two out] plates 7,b74 ,illu/ration3 ,fig4 #ia4 ,,portable ,,electric ,,purifi] ,let ea* %eet be #a-a_/b in*es wide & #e-a_/b in*es ?ick4 ,"o-half in* f ! upp] ends ( ! two outside plates 7,b1 ,b7 bore bolt holes 7,c71 ea* ( ^! holes be+ a qu>t] ( an in* f ! edge ( ! plate4 ,! inside plate 7,a7 has two l>ge holes 7,d7 correspond+ ) ! small holes 7,c7 9 ! outside plates4 ,at ! upp] end ( ?is plate =m a w+ 7,e71 #a_/b in* wide & #a_/b in* long1 provid$ ) a small hole = a bolt4 ,next cut out two h>d-rubb] blocks 7,f71 ea* #a-a_/b in*es long1 #a in* wide & #c_/h in* ?ick1 & !n bore a hole 7,g7 ?r\gh ea*1 correspond+ ) ! small holes 7,c7 9 ! plates 7,b74 ,! ma*9e is n[ ready to be assembl$4 ,if ! inn] plate is #a_/h in* ?ick & ! out] plates ea* #a_/af in* ?ick1 use two small eigh?-in* bolts #a-a_/d in*es long1 & clamp toge!r ! ?ree plates ) ^! bolts4 ,"o ( ! bolts may be us$ to atta* !reto "o ( ! electric wires 7,h71 & ! o!r wire 7,i7 is atta*$ by a bolt to ! w+ 7,e74 ,illu/ration3 ,figs4 #ib-ie4 ,,details ,,( ,,portable ,,purifi] ,su* a device w answ] = a #aaj-volt circuit1 9 ord9>y wat]4 ,n[ fill a glass ne>ly full ( wat]1 & /& ! purifi] 9 ! glass4 ,)9 a few m9utes ! action ( electrolysis w be app>5t by ! =mation ( num]\s bubbles on ! plates1 foll[$ by ! decomposition ( ! organic matt] 9 ! wat]4 ,at fir/ ! floccul5t decompos$ matt] w rise to ! surface ( ! wat]1 b be=e _m m9utes x w settle to ! bottom ( ! glass & leave cle> wat] above4 ,,purification ,,& ,,sep>ation ,,( ,,metals4--,?is electrolytic action is utiliz$ 9 metallurgy = ! purpose ( produc+ pure metals1 b x is m l>gely us$ to sep>ate copp] f its base4 ,9 ord] to utilize a curr5t = ?is purpose1 a high amp]e fl[ & l[ voltage are requir$4 ,! %eets ( copp]1 conta9+ all ( its impurities1 are plac$ )9 a tank1 p>allel ) a ?9 copp] %eet4 ,! impure %eet is connect$ ) ! positive pole ( an electroplat+ dynamo1 & ! ?9 %eet ( copp] is connect$ ) ! negative pole4 ,! electrolyte 9 ! tank is a solution ( sulphate ( copp]4 ,! action ( ! curr5t w cause ! pure copp] 9 ! impure %eet to dis9tegrate & x is !n c>ri$ ov] & deposit$ ^u ! ?9 %eet1 ?is action cont9u+ until ! impure %eet is entirely eat5 away4 ,all ! impurities :i* 7 9 ! %eet fall to ! bottom ( ! tank4 ,o!r metals are treat$ 9 ! same way1 & ?is treatm5t has a v wide range ( usefulness4 ,,electroplat+4--,! next feature to be consid]$ 9 electrolysis is a mo/ int]e/+ & useful "o1 because a *eap or inf]ior metal may be coat$ by a m exp5sive metal4 ,silv] & nickel plat+ are br\ght ab\t by ?is action ( a curr5t pass+ ?r\gh metals1 :i* are imm]s$ 9 an electrolyte4 ,,plat+ ,,iron ,,) ,,copp]4--,we h room 9 ?is *apt] = only "o concrete example ( ?is "w1 :i*1 ) suitable modifications1 is an example ( ! art z practic$ comm]cially4 ,iron1 to a consid]able ext5t1 is n[ be+ coat$ ) copp] to pres]ve x f ru/4 ,to c>ry out ?is "w1 h[ev]1 an electroplat+ dynamo1 ( l>ge amp]age1 is requir$1 ! amp]age1 ( c\rse1 dep5d+ ^u ! surface to be treat$ at "o "t4 ,! pressure %\ld n exce$ #e volts4 ,! iron surface to be treat$ %\ld fir/ be ?or\ghly cleans$1 & !n imm$iately put into a tank conta9+ a cyanide ( copp] solution4 ,two =ms ( copp] solution are us$1 namely1 ! cyanide1 :i* is a salt solution ( copp]1 & ! sulphate1 :i* is an acid solution ( copp]4 ,cyanide is fir/ us$ because x does n attack ! iron1 z w\ld be ! case if ! sulphate solution %\ld fir/ come into contact ) ! iron4 ,a %eet ( copp]1 t]m$ ! anode1 is !n plac$ )9 ! tank1 p>allel ) ! surface to be plat$1 kn[n z ! ca?ode1 & s m\nt$ t x may be adju/$ to or f ! iron surface1 or ca?ode4 ,a direct curr5t ( electricity is !n caus$ to fl[ ?r\gh ! copp] plate & into ! iron plate or surface1 & ! plat+ proce$$ ) until ! iron surface has a ?9 film ( copp] deposit$ !reon4 ,?is is a sl[ process ) ! cyanide solution1 s x is discont9u$ z soon z possible1 aft] ! iron surface has be5 completely cov]$ ) copp]4 ,?is copp] surface is ?or\ghly clean$ (f to remove !refrom ! sal9e or alkal9e solution1 & x is !n imm]s$ )9 a ba?1 conta9+ a solution ( sulphate ( copp]4 ,! curr5t is !n ?r[n on & all[$ s to rema9 until x has deposit$ ! prop] ?ickness ( copp]4 ,,direction ,,( ,,curr5t4--,if a copp] & an iron plate are put into a copp] solution & connect$ up 9 circuit ) ea* o!r1 a prim>y batt]y is !reby =m$1 :i* w g5]ate electricity4 ,9 ?is case1 ! iron w be positive & ! copp] negative1 s t ! curr5t )9 su* a cell w\ld fl[ f ! iron 79 ?is in/ance1 ! anode7 to ! negative1 or ca?ode4 ,! action ( electroplat+ rev]ses ?is process & causes ! curr5t to fl[ f ! copp] to ! iron 79 ?is in/ance1 ! ca?ode74 ,,*apt] ,,xiv ,,electric ,,heat+1 ,,!rmo ,,electricity ,,g5]at+ ,,heat ,,9 ,a ,,wire4--,:5 a curr5t ( electricity passes ?r\gh a conductor1 l a wire1 m or less heat is develop$ 9 ! conductor4 ,?is heat may be s small t x _c be measur$1 b x is1 nev]!less1 pres5t 9 a great] or less degree4 ,conductors (f] a resi/ance to ! passage ( a curr5t1 j ! same z wat] f9ds a resi/ance 9 pipes ?r\gh :i* x passes4 ,?is resi/ance is measur$ 9 ohms1 z expla9$ 9 a prec$+ *apt]1 & x is ?is resi/ance :i* is utiliz$ = electric heat+4 ,,resi/ance ,,( ,,sub/ances4--,silv] (f]s less resi/ance to ! passage ( a curr5t ?an any o!r metal1 ! next 9 ord] is copp]1 :ile iron is1 comp>atively1 a poor conductor4 ,! foll[+ is a p>tial li/ ( metals1 %[+ _! relative conductivity3 ,silv] #a4 ,copp] #a4jd to #a4ji ,gold #a4ch to #a4da ,alum9um #a4fd ,z9c #c4gi ,nickel #d4fi ,iron #f4ef ,t9 #h4i ,lead #ac4b ,g]man ,silv] #ab4b to #ae ,f ?is table x w be se5 t1 = in/ance1 iron (f]s six & a half times ! resi/ance ( silv]1 & t ,g]man silv] has fifte5 times ! resi/ance ( silv]4 ,?is table is made up ( /r&s ( ! diff]5t metals ( ! same diamet]s & l5g?s1 s z to obta9 _! relative values4 ,,sizes ,,( ,,conductors4--,ano!r ?+1 h[ev]1 mu/ be und]/ood4 ,if two conductors ( ! same metal1 hav+ diff]5t diamet]s1 receive ! same curr5t ( electricity1 ! small conductor w (f] a great] resi/ance ?an ! l>ge conductor1 h5ce w g5]ate m heat4 ,?is c be (fset by increas+ ! diamet] ( ! conductor4 ,! metal us$ is1 !re=e1 ( importance1 on acc\nt ( ! co/ involv$4 ,,comp>ison ,,( ,,metals4--,a conductor ( alum9um1 say1 #aj feet long & ( ! same weight z copp]1 has a diamet] two & a qu>t] times great] ?an copp]2 b z ! resi/ance ( alum9um is #ej p] c5t4 m ?an t ( silv]1 x w be se5 t1 weight = weight1 copp] is ! *eap]1 p>ticul>ly z alum9um co/s fully ?ree times z mu* z copp]4 ,illu/ration3 ,fig4 #if4 ,,simple ,,electric ,,heat] ,! table %[s t ,g]man silv] has ! highe/ resi/ance4 ,( c\rse1 !re are o!r metals1 l antimony1 plat9um & ! l1 :i* h /ill high] resi/ance4 ,g]man silv]1 h[ev]1 is mo/ commonly us$1 al?\gh !re are v>i\s alloys ( metal made :i* h high resi/ance & are *eap]4 ,! pr9ciple ( all electric heat]s is ! same1 namely1 ! resi/ance ( a conductor to ! passage ( a curr5t1 & an illu/ration ( a wat] heat] w %[ ! elem5t>y pr9ciples 9 all ( ^! devices4 ,a ,,simple ,,electric ,,heat]4--,9 ,fig4 #if ! illu/ration %[s a cup or hold] 7,a7 = ! wire1 made ( h>d rubb]4 ,?is may be ( su* diamet] z to fit ^u & =m ! cov] = a glass 7,b74 ,! rubb] %\ld be #a_/b in* ?ick4 ,two holes are bor$ ?r\gh ! rubb] cup1 & ?r\gh !m are screw$ two r\nd-head$ screws 7,c1 ,d71 ea* screw be+ #a-a_/b in*es long1 s !y w project an in* bel[ ! cap4 ,ea* screw %\ld h a small hole 9 its l[] end to receive a p9 7,e7 :i* w prev5t ! resi/ance wire f slipp+ (f4 ,! resi/ance wire 7,f7 is coil$ = a suitable l5g?1 dep5d5t ^u ! curr5t us$1 "o end be+ fa/5$ by wrapp+ x ar\nd ! screw 7,c74 ,! o!r end ( ! wire is !n br\ght upw>dly ?r\gh ! int]ior ( ! coil & secur$ 9 l mann] to ! o!r screw 7,d74 ,caution mu/ be us$ to prev5t ! diff]5t coils or turns f t\*+ ea* o!r4 ,:5 complet$1 ! coil may be imm]s$ 9 wat]1 ! curr5t turn$ on1 & left s until ! wat] is suffici5tly heat$4 ,illu/ration3 ,figs4 #ig-ih4 ,,resi/ance ,,device ,,h[ ,,to ,,arrange ,,= ,,quantity ,,( ,,curr5t ,,us$4--,x is difficult to det]m9e j ! prop] l5g? ! coil %\ld be1 or ! sizes ( ! wire1 unless y "k :at k9d ( curr5t y h4 ,y may1 h[ev]1 rig up y\r own app>atus = ! purpose ( mak+ x fit y\r heat]1 by prep>+ a base ( wood 7,a7 #h in*es long1 #c in*es wide & #a in* ?ick4 ,on ?is m\nt f\r electric lamp sockets 7,b74 ,!n connect ! inlet wire 7,c7 by means ( %ort pieces ( wire 7,d7 ) all ! sockets on "o side4 ,! outlet wire 7,e7 %\ld !n be connect$ up ) ! o!r sides ( ! sockets by ! %ort wires 7,f74 ,if1 n[1 we h "o #af-;c&lep[] lamp 9 "o ( ! sockets1 !re is a half amp]e go+ ?r\gh ! wires 7,c1 ,f74 ,if !re are two lamps on ! bo>d y w h #a amp]e1 & s on4 ,by ?is means y may readily det]m9e h[ mu* curr5t y are us+ & x w also af=d y a means ( f9d+ out :e!r y h too mu* or too little wire 9 y\r coil to d ! "w4 ,illu/ration3 ,fig4 #ii4 ,,plan ,,view ,,( ,,electric ,,iron ,,an ,,electric ,,iron4--,an electric iron is made 9 ! same way4 ,! upp] side ( a flatiron has a circul> or oval depression 7,a7 ca/ !re91 & a spool ( slate 7,b7 is made s x w fit into ! depression & ! high resi/ance wire 7,c7 is w\nd ar\nd ?is spool1 & insulat+ mat]ial1 su* z asbe/os1 mu/ be us$ to pack ar\nd x4 ,c5trally1 ! slate spool has an upw>dly project+ circul> ext5sion 7,d7 :i* passes ?r\gh ! cap or cov] 7,e7 ( ! iron4 ,! wires ( ! resi/ance coil are !n br\ght ?r\gh ?is circul> ext5sion & are connect$ up ) ! s\rce ( electrical supply4 ,wires are n[ sold = ?is purpose1 :i* are adapt$ to )/& an int5se heat4 ,illu/ration3 ,fig4 #ajj4 ,,section ,,( ,,electric ,,iron ,! =ego+ example ( ! use ( ! curr5t1 ?r\gh resi/ance wires1 has a v wide application1 & any boy1 ) ^! examples be=e him1 c readily make ^! devices4 ,,!rmo ,,electricity4--,x has long be5 ! dream ( sci5ti/s to conv]t heat directly into electricity4 ,! pres5t practice is to use a boil] to g5]ate /eam1 an eng9e to provide ! motion1 & a dynamo to conv]t t motion into electricity4 ,! result is t !re is loss 9 ! process ( conv]t+ ! fuel heat into /eam2 loss to *ange ! /eam into motion1 & loss to make electricity out ( ! motion ( ! eng9e4 ,by us+ wat]-p[] !re is less actual loss2 b wat]-p[] is n available ev]y:]e4 ,,conv]t+ ,,heat ,,directly ,,into ,,electricity4--,heat may be conv]t$ directly into electricity )\t us+ a boil]1 an eng9e or a dynamo1 b x has n be5 successful f a comm]cial /&po9t4 ,x is int]e/+1 h[ev]1 to "k & und]/& ! subject1 & = t reason x is expla9$ h]e94 ,,metals2 ,,electric ,,positive-,,negative4--,to und]/& ! pr9ciple1 x may be /at$ t all metals are electrically positive-negative to ea* o!r4 ,y w rememb] t x has h]e9be=e be5 /at$ t if1 = in/ance1 iron & copp] are put into an acid solution1 a curr5t w be creat$ or g5]at$ !reby4 ,s ) z9c & copp]1 ! usual prim>y batt]y elem5ts4 ,9 all su* cases an electrolyte is us$4 ,!rmo-electricity disp5ses ) ! electrolyte1 & no?+ is us$ b ! metallic elem5ts & heat4 ,! ^w !rmo means heat4 ,if1 n[1 we c select two /rips ( diff]5t metals1 & place !m z f> ap>t z possible--t is1 9 _! positive-negative relations ) ea* o!r1 & unite ! end ( "o ) "o end ( o!r by means ( a rivet1 & !n heat ! rivet$ ends1 a curr5t w be g5]at$ 9 ! /rips4 ,if1 = in/ance1 we use an iron 9 conjunction ) a copp] /rip1 ! curr5t w fl[ f ! copp] to ! iron1 because copp] is positive to iron1 & iron negative to copp]4 ,x is f ?is t ! t]m positive-negative is tak54 ,! two metals mo/ available1 :i* are ?us f>!/ ap>t 9 ! scale ( positive-negative relation1 are bismu? & antimony4 ,illu/ration3 ,fig4 #aja4 ,,!rmo-,,electric ,,c\ple ,9 ,fig4 #aja is %[n a !rmo-electric c\ple 7,a1 ,b7 rivet$ toge!r1 ) ?9 out] ends connect$ by means ( a wire 7,c7 to =m a circuit4 ,a galvanomet] 7,d7 or o!r curr5t-te/+ means is plac$ 9 ?is circuit4 ,a lamp is plac$ bel[ ! jo9$ ends4 ,,!rmo-,,electric ,,c\ples4--,any numb] ( ^! c\ples may be put toge!r & jo9$ at ea* end to a common wire & a fairly l>ge fl[ ( curr5t obta9$ !reby4 ,"o ?+ mu/ be obs]v$3 ,a curr5t w be g5]at$ only s long z !re exi/s a diff]5ce 9 temp]ature betwe5 ! inn] & ! out] ends ( ! b>s 7,a1 ,b74 ,?is may be accompli%$ by wat]1 or any o!r cool+ means :i* may sugge/ itself4 ,,*apt] ,,xv ,,alt]nat+ ,,curr5ts1 ,,*ok+ ,,coils1 ,,trans=m]s1 ,,conv]t]s ,,& ,,rectifi]s ,,direct ,,curr5t4--,:5 a curr5t ( electricity is g5]at$ by a cell1 x is assum$ to move along ! wire 9 "o direction1 9 a /eady1 cont9u\s fl[1 & is call$ a direct curr5t4 ,?is direct curr5t is a natural "o if g5]at$ by a cell4 ,,alt]nat+ ,,curr5t4--,on ! o!r h&1 ! natural curr5t g5]at$ by a dynamo is alt]nat+ 9 its "*--t is1 x is n a direct1 /eady fl[ 9 "o direction1 b1 in/ead1 x fl[s = an in/ant 9 "o direction1 !n 9 ! o!r direction1 & s on4 ,a direct-curr5t dynamo su* z we h %[n 9 ,*apt] ,,iv1 is mu* easi] to expla91 h5ce x is illu/rat$ to %[ ! ?ird me?od us$ 9 g5]at+ an electric curr5t4 ,x is a difficult matt] to expla9 ! pr9ciple & op]ation ( alt]nat+ curr5t ma*9es1 )\t becom+1 9 a measure1 too te*nical = ! purposes ( ?is book1 b x is important to "k ! fundam5tals involv$1 s t ! op]ation & uses ( c]ta9 app>atus1 l ! *ok+ coil1 trans=m]s1 rectifi]s & conv]t]s1 may be expla9$4 ,,! ,,magnetic ,,field4--,x has be5 /at$ t :5 a wire passes ?r\gh ! magnetic field ( a magnet1 s z to cut ! l9es ( =ce fl[+ out f ! end ( a magnet1 ! wire w receive a *>ge ( electricity4 ,illu/ration3 ,fig4 #ajb4 ,,cutt+ ,a ,,magnetic ,,field ,to expla9 ?is1 /udy ,fig4 #ajb1 9 :i* is a b> magnet 7,a74 ,if we take a metal wire 7,b7 & b5d x 9 ! =m ( a loop1 z %[n1 & m\nt ! ends on j\rnal-be>+ blocks1 ! wire may be rotat$ s t ! loop w pass ?r\gh ! magnetic field4 ,:5 ?is takes place1 ! wire receives a *>ge ( electricity1 :i* moves1 say1 9 ! direction ( ! d>ts1 & w make a complete circuit if ! ends ( ! loop$ wire are jo9$1 z %[n by ! conductor 7,d74 ,,action ,,( ,,! ,,magnetiz$ ,,wire4--,y w rememb]1 also t we h po9t$ out h[1 :5 a curr5t passes ov] a wire1 x has a magnetic field ext5d+ out ar\nd x at all po9ts1 s t :ile x is pass+ ?r\gh ! magnetic field ( ! magnet 7,a71 x becomes1 9 a measure1 a magnet ( its own & tries to set up 9 bus9ess = itself z a g5]ator ( electricity4 ,b :5 ! loop leaves ! magnetic field1 ! magnetic or electrical impulse 9 ! wire also leaves x4 ,,! ,,movem5t ,,( ,a ,,curr5t ,,9 ,a ,,*>g$ ,,wire4--,y\r att5tion is direct$1 also1 to ano!r /atem5t1 h]et(ore made1 namely1 t :5 a curr5t f a *>g$ wire passes by induction to a wire across space1 s z to *>ge x ) an electric curr5t1 x moves along ! *>g$ wire 9 a direction opposite to t ( ! curr5t 9 ! *>g+ wire4 ,n[1 ! d>ts %[ ! direction 9 :i* ! curr5t moves :ile x is approa*+ & pass+ ?r\gh ! magnetic field4 ,b ! mom5t ! loop is ab\t to pass out ( ! magnetic field1 ! curr5t 9 ! loop surges back 9 ! opposite direction1 & :5 ! loop has made a revolution & is aga9 ent]+ ! magnetic field1 x mu/ aga9 *ange ! direction ( fl[ 9 ! curr5t1 & ?us produce alt]nations 9 ! fl[ !re(4 ,let u illu/rate ?is by %[+ ! f\r positions ( ! revolv+ loop4 ,9 ,fig4 #ajc ! loop 7,b7 is 9 ! middle ( ! magnetic field1 mov+ upw>dly 9 ! direction ( ! curv$ d>t 7,a71 & :ile 9 t position ! voltage1 or ! electrical impulse1 is ! mo/ int5se4 ,! curr5t us$ fl[s 9 ! direction ( ! d>ts 7,c7 or to ! left4 ,9 ,fig4 #ajd1 ! loop 7,a7 has gone beyond ! influ5ce ( ! magnetic field1 & n[ ! curr5t 9 ! loop tries to return1 or rev]se itself1 z %[n by ! d>t 7,d74 ,x is a reaction t causes ! curr5t to die out1 s t :5 ! loop has rea*$ ! po9t f>!/ f ! magnet1 z %[n 9 ,fig4 #aje1 !re is no curr5t 9 ! loop1 or1 if !re is any1 x moves fa9tly 9 ! direction ( ! d>t 7,e74 ,illu/ration3 ,figs4 #ajc-ajf4 ,,illu/rat+ ,,alt]nations ,,curr5t ,,rev]s+ ,,itself4--,:5 ! loop rea*es its l[e/ po9t 7,fig4 #ajf7 x aga9 comes )9 ! magnetic field & ! curr5t comm5ces to fl[ back to its orig9al direction1 z %[n by d>ts 7,c74 ,,self-,,induction4--,?is t5d5cy ( a curr5t to rev]se itself1 "u ! conditions cit$1 is call$ self-induction1 or inductance1 & x w\ld be well to keep ?is 9 m9d 9 pursu+ ! /udy ( alt]nat+ curr5ts4 ,y w see f ! =ego+1 t ! alt]nations1 or ! *ange ( direction ( ! curr5t1 dep5ds ^u ! spe$ ( rotation ( ! loop pa/ ! end ( ! magnet4 ,illu/ration3 ,figs4 #ajg-ajh4 ,,=m ,,= ,,increas+ ,,alt]nations ,in/ead1 !re=e1 ( us+ a s+le loop1 we may make f\r loops 7,fig4 #ajg71 :i* at ! same spe$ z we _h 9 ! case ( ! s+le loop1 w give f\r alt]nations1 in/ead ( "o1 & /ill fur!r1 to increase ! p]iods ( alt]nation1 we may use ! f\r loops & two magnets1 z 9 ,fig4 #ajh4 ,by hav+ a suffici5t numb] ( loops & ( magnets1 !re may be #dj1 #ej1 #fj1 #hj1 #ajj or #abj su* alt]nat+ p]iods 9 ea* second4 ,"t1 !re=e1 is an elem5t 9 ! op]ation ( alt]nat+ curr5ts4 ,let u n[ illu/rate ! mann] ( connect+ up & build+ ! dynamo1 s z to d]ive ! curr5t f x4 ,9 ,fig4 #aji1 ! loop 7,a7 %[s1 = conv5i5ce1 a pair ( be>+s 7,b74 ,a contact f+] 7,c7 re/s on ea*1 & to ^! ! circuit wire 7,d7 is atta*$4 ,d n confuse ^! contact f+]s ) ! commutator bru%es1 %[n 9 ! direct-curr5t motor1 z !y are !re m]ely = ! purpose ( mak+ contact betwe5 ! revolv+ loop 7,a7 & /ation>y wire 7,d74 ,illu/ration3 ,fig4 #aji4 ,,connection ,,( ,,alt]nat+ ,,dynamo ,,armature ,,bru%es ,,9 ,a ,,direct-,,curr5t ,,dynamo4--,! object ( ! bru%es 9 ! direct-curr5t dynamo1 9 connection ) a commutator1 is to conv]t ?is inductance ( ! wire1 or ?is ef=t to rev]se itself into a curr5t :i* w g 9 "o direction all ! "t1 & n 9 bo? directions alt]nately4 ,to expla9 ?is m fully att5tion is direct$ to ,figs4 #aaj & #aaa4 ,let ,a repres5t ! armature1 ) a pair ( grooves 7,b7 = ! wires4 ,! commutator is made ( a split tube1 ! p>ts s divid$ be+ insulat$ f ea* o!r1 & 9 ,fig4 #aaj1 ! upp] "o1 we %all call & designate ! positive 77 & ! l[] "o ! negative 7-74 ,! armature wire 7,c7 has "o end atta*$ to ! positive commutator t]m9al & ! o!r end ( ?is wire is atta*$ to ! negative t]m9al4 ,illu/ration3 ,fig4 #aaj4 ,,direct ,,curr5t ,,dynamo ,"o bru% 7,d7 contacts ) ! positive t]m9al ( ! commutator & ! o!r bru% 7,e7 ) ! negative t]m9al4 ,let u assume t ! curr5t impulse imp>t$ to ! wire 7,c7 is 9 ! direction ( ! d>t 7,f1 ,fig4 #aaj74 ,! curr5t w !n fl[ ?r\gh ! positive 77 t]m9al ( ! commutator to ! bru% 7,d71 & f ! bru% 7,d7 ?r\gh ! wire 7,g7 to ! bru% 7,e71 :i* contacts ) ! negative 7-7 t]m9al ( ! commutator4 ,?is w cont9ue to be ! case1 :ile ! wire 7,c7 is pass+ ! magnetic field1 & :ile ! bru% 7,d7 is 9 contact ) ! positive 77 t]m9al4 ,b :5 ! armature makes a half turn1 or :5 x rea*es t po9t :]e ! bru% 7,d7 contacts ) ! negative 7-7 t]m9al1 & ! bru% 7,e7 contacts ) ! positive 77 t]m9al1 a *ange 9 ! direction ( ! curr5t ?r\gh ! wire 7,g7 takes place1 unless some?+ has happ5$ to *ange x be=e x has rea*$ ! bru%es 7,d1 ,e74 ,illu/ration3 ,fig4 #aaa4 ,,circuit ,,wires ,,9 ,,direct ,,curr5t ,,dynamo ,n[1 ?is *ange is j exactly :at has happ5$ 9 ! wire 7,c71 z we h expla9$4 ,! curr5t attempts to rev]se itself & />t out on bus9ess ( its own1 s to speak1 ) ! result t :5 ! bru%es 7,d & ,e7 contact ) ! negative & positive t]m9als1 respectively1 ! surg+ curr5t 9 ! wire 7,c7 is go+ 9 ! direction ( ! d>t 7,h7--t is1 :ile1 9 ,fig4 #aaj1 ! curr5t fl[s f ! wire 7,c7 into ! positive t]m9al1 & out ( ! negative t]m9al into ! wire 7,c71 ! conditions are exactly rev]s$ 9 ,fig4 #aaa4 ,"h ! curr5t 9 wire ,c fl[s into ! negative 7-7 t]m9al1 & f ! positive 77 t]m9al into ! wire ,c1 s t 9 ei!r case ! curr5t w fl[ out ( ! bru% ,d & into ! bru% ,e1 ?r\gh ! ext]nal circuit 7,g74 ,x w be se51 !re=e1 t 9 ! direct-curr5t motor1 advantage is tak5 ( ! surg+1 or back-&-=? movem5t1 ( ! curr5t to pass x along 9 "o direction1 :]eas 9 ! alt]nat+ curr5t no su* *ange 9 direction is attempt$4 ,,alt]nat+ ,,positive ,,& ,,negative ,,poles4--,! alt]nat+ curr5t1 ow+ to ?is surg+ movem5t1 makes ! poles alt]nately positive & negative4 ,to express ?is m cle>ly1 suppos+ we take a l9e 7,a1 ,fig4 #aab71 :i* is call$ ! z]o l9e1 or l9e ( no electricity4 ,! curr5t may be repres5t$ by ! zigzag l9e 7,b74 ,! l9es 7,b7 above z]o 7,a7 may be designat$ z positive1 & ^? bel[ ! l9e z negative4 ,! pol>ity rev]ses at ! l9e ,a1 goes up to ,d1 :i* is ! maximum int5sity or voltage above z]o1 &1 :5 ! curr5t falls & crosses ! l9e ,a1 x goes 9 ! opposite direction to ,e1 :i* is its maximum voltage 9 ! o!r direction4 ,9 po9t ( "t1 if x takes "o second = ! curr5t to g f ,c to ,f1 on ! d[n l9e1 !n x takes only a half second to g f ,c to ,g1 s t ! l9e ,a repres5ts ! "t1 & ! l9e ,h ! int5sity1 a complete cycle be+ =m$ f ,c1 ,d1 ,f1 !n ?r\gh ,f1 ,e1 ,c1 & s on4 ,illu/ration3 ,fig4 #aab4 ,,alt]nat+ ,,pol>ity ,,l9es ,,h[ ,,an ,,alt]nat+ ,,dynamo ,,is ,,made4--,x is n[ necess>y to apply ^! pr9ciples 9 ! con/ruction ( an alt]nat+-curr5t ma*9e4 ,fig4 #aac is a diagram repres5t+ ! v>i\s elem5ts1 & ! circuit+4 ,illu/ration3 ,fig4 #aac4 ,,alt]nat+ ,,curr5t ,,dynamo ,let ,a repres5t ! r+ or frame conta9+ ! inw>dly project+ field magnet cores 7,b74 ,c is ! %aft on :i* ! armature revolves1 & ?is c>ries ! :eel 7,d71 :i* has z _m radially dispos$ magnet cores 7,e7 z !re are ( ! field magnet cores 7,b74 ,! %aft 7,c7 also c>ries two pulleys ) r+s !reon4 ,"o ( ^! r+s 7,f7 is = "o end ( ! armature w9d+1 & ! o!r r+ 7,g7 = ! o!r end ( ! armature wire4 ,,! ,,w9d+s4--,! w9d+ is z foll[s3 ,"o wire1 z at ,h1 is fir/ coil$ ar\nd "o magnet core1 ! turn+s be+ to ! "r4 ,! outlet t]m9al ( ?is wire is !n c>ri$ to ! next magnet core & w\nd ar\nd t1 9 ! opposite direction1 & s on1 s t ! t]m9al ( ! wire is br\ght out1 z at ,i1 all ( ^! wires be+ connect$ to b9d+ po/s 7,j1 ,j'71 to :i*1 also1 ! work+ circuits are atta*$4 ,,! ,,armature ,,wires4--,! armature wires1 9 l mann]1 run f ! r+ 7,g7 to "o armature core1 be+ w\nd f "r to left1 !n to ! next core1 :i* is w\nd to ! "r1 aft]w>d to ! next core1 :i* is w\nd to ! left1 & s on1 ! f9al end ( ! wire be+ connect$ up ) ! o!r r+ 7,f74 ,! nor? 7,n7 & ! s\? 7,s7 poles are indicat$ 9 ! diagram4 ,,*ok+ ,,coil4--,! self-induction 9 a curr5t ( ?is k9d is utiliz$ 9 transmitt+ electricity to great di/ances4 ,wires (f] resi/ance1 or !y imp$e ! fl[ ( a curr5t1 z h]e9be=e /at$1 s t x is n economical to transmit a direct curr5t ov] long di/ances4 ,?is c be done m effici5tly by means ( ! alt]nat+ curr5t1 :i* is subject to f> less loss ?an is ! case ) ! direct curr5t4 ,x af=ds a means :]eby ! fl[ ( a curr5t may be *eck$ or r$uc$ )\t dep5d+ ^u ! resi/ance (f]$ by ! wire ov] :i* x is transmitt$4 ,?is is done by means ( :at is call$ a *ok+ coil4 ,x is m]ely a coil ( wire1 w\nd ^u an iron core1 & ! curr5t to be *ok$ passes ?r\gh ! coil4 ,to illu/rate ?is1 let u take an arc lamp design$ to use a #ej-volt curr5t4 ,if a curr5t is suppli$ to x c>ry+ #ajj volts1 x is obvi\s t !re are #ej volts m ?an are ne$$4 ,we mu/ take c>e ( ?is excess ( #ej volts )\t los+ x1 z w\ld happ5 7 we to locate a resi/ance ( "s k9d 9 ! circuit4 ,?is result we accompli% by ! introduction ( ! *ok+ coil1 :i* has ! effect ( absorb+ ! excessive #ej volts1 ! action be+ due to its quality ( self-induction1 ref]r$ to 9 ! =ego+4 ,illu/ration3 ,fig4 #aad4 ,,*ok+ ,,coil ,9 ,fig4 #aad1 ,a is ! *ok+ coil & ,b an arc lamp1 connect$ up1 9 s]ies1 ) ! *ok+ coil4 ,,! ,,trans=m]4--,x is m economical to transmit #aj1jjj volts a long di/ance ?an #a1jjj volts1 because ! l[] ! pressure1 or ! voltage1 ! l>g] mu/ be ! conductor to avoid loss4 ,x is = ?is reason t #ejj volts1 or m1 are us$ on electric railways4 ,= electric light purposes1 :]e ! curr5t goes into dwell+s1 ev5 ?is is too high1 s a trans=m] is us$ to take a high-voltage curr5t f ! ma9 l9e & trans=m x into a l[ voltage4 ,?is is done by means ( two di/9ct coils ( wire1 w\nd ^u an iron core4 ,illu/ration3 ,fig4 #aae4 ,a ,,trans=m] ,9 ,fig4 #aae ! core is ,o-%ap$1 s t a prim>y w9d+ 7,a71 f ! electrical s\rce1 c be w\nd ^u "o limb1 & ! second>y w9d+ 7,b7 w\nd ar\nd ! o!r limb4 ,! wires1 to supply ! lamps1 run f ! second>y coil4 ,!re is no electrical connection betwe5 ! two coils1 b ! action f ! prim>y to ! second>y coil is solely by induction4 ,:5 a curr5t passes ?r\gh ! prim>y coil1 ! surg+ movem5t1 h]et(ore expla9$1 is transmitt$ to ! iron core1 & ! iron core1 9 turn1 transmits ?is electrical en]gy to ! second>y coil4 ,,h[ ,,! ,,voltage ,,is ,,det]m9$4--,! voltage produc$ by ! second>y coil w dep5d ^u sev]al ?+s1 namely1 ! /r5g? ( ! magnetism transmitt$ to x2 ! rapidity1 or p]iodicity ( ! curr5t1 & ! numb] ( turns ( wire ar\nd ! coil4 ,! voltage is dep5d5t ^u ! l5g? ( ! w9d+4 ,b ! voltage may also be increas$1 z well z decreas$4 ,if ! prim>y has1 we w say1 #ajj turns ( wire1 & has #bjj volts1 & ! second>y has #ej turns ( wire1 ! second>y w give =? only "o-half z mu* z ! prim>y1 or #ajj volts4 ,if1 on ! o!r h&1 #djj volts w\ld be requir$1 ! second>y %\ld h #bjj turns 9 ! w9d+4 ,,voltage ,,& ,,amp]age ,,9 ,,trans=m]s4--,x mu/ n be und]/ood t1 by increas+ ! voltage 9 ?is way1 we are gett+ t mu* m electricity4 ,if ! prim>y coil1 ) #ajj turns1 produces a curr5t ( #bjj volts & #ej amp]es1 :i* w\ld be #bjj #ej #aj1jjj watts1 & ! second>y coil has #ej turns1 we %all h #ajj volts & #ajj amp]es3 #ajj 7,v47 #ajj 7,a47 #aj1jjj watts4 ,or1 if1 on ! o!r h&1 our second>y w9d+ is compos$ ( #bjj turns1 we %all h #djj volts & #be amp]es1 #djj 7volts7 #be 7amp]es7 also gives #aj1jjj watts4 ,necess>ily1 !re w be "s loss1 b ! =ego+ is (f]$ z ! !oretical basis ( calculation4 ,,*apt] ,,xvi ,,electric ,,light+ ,! mo/ important /ep 9 ! electric field1 aft] ! dynamo _h be5 br\ght to a fairly workable condition1 0 its utilization to make light4 ,x 0 long kn[n prior to ! discov]y ( practical electric dynamos1 t ! electric curr5t w\ld produce an int5se heat4 ,ord9>y fuels "u c]ta9 favorable conditions w produce a temp]ature ( #d1ejj degrees ( heat2 b by means ( ! electric arc1 z high z six1 eight & t5 ?\s& degrees are available4 ,! fact t :5 a conductor1 9 an electric curr5t1 is sev]$1 a sp>k w foll[ ! draw+ "p ( ! brok5 ends1 l$ _m sci5ti/s to believe1 ev5 be=e ! dynamo 0 9 a practical %ape1 t electricity1 soon] or lat]1 w\ld be employ$ z ! great light+ ag5t4 ,:5 ! dynamo f9ally rea*$ a /age 9 developm5t :]e its op]ation c\ld be dep5d$ on1 & 0 made rev]sible1 ! fir/ active /eps 7 tak5 to n only produce1 b to ma9ta9 an arc betwe5 two electrodes4 ,x w\ld be difficult & t$i\s to foll[ out ! fir/ exp]im5ts 9 detail1 & x might1 also1 be useless1 z in=mation1 9 view ( ! pres5t k ( ! sci5ce4 ,a few /eps 9 ! c\rse ( ! developm5t are1 h[ev]1 necess>y to a complete und]/&+ ( ! subject4 ,ref]5ce has be5 made 9 a previ\s *apt] to :at is call$ ! ,electric ,arc1 produc$ by slightly sep>at$ conductors1 across :i* ! electric curr5t jumps1 produc+ ! brilliantly light$ area4 ,?is light is produc$ by ! combu/ion ( ! c>bon ( :i* ! electrodes are compos$4 ,?us1 ! illum9ation is ! result ( directly burn+ a fuel4 ,! curr5t1 9 pass+ f "o electrode to ! o!r1 ?r\gh ! gap1 produces su* an int5se heat t ! fuel ?r\gh :i* ! curr5t passes is consum$4 ,c>bon 9 a comp>atively pure /ate is difficult to ignite1 ow+ to its great resi/ance to heat4 ,at ab\t #g1jjj degrees x w fuse1 & pass into a vapor :i* causes ! int5se illum9ation4 ,! e>lie/ =m ( electric light+ 0 by means ( ! arc1 9 :i* ! light is ma9ta9$ s long z ! electrodes 7 kept a c]ta9 di/ance ap>t4 ,to d ?is requires delicate me*anism1 = ! reason t :5 contact is made1 & ! curr5t fl[s ?r\gh ! two electrodes1 :i* are connect$ up directly ) ! coils ( a magnet1 ! cores1 or armatures1 w be magnetiz$4 ,! result is t ! electrode1 connect$ ) ! armature ( ! magnet1 is drawn away f ! o!r electrode1 & ! arc is =m$1 betwe5 ! sep>at$ ends4 ,z ! curr5t also passes ?r\gh a resi/ance coil1 ! mom5t ! ends ( ! electrodes are sep>at$ too great a di/ance1 ! resi/ance prev5ts a fl[ ( ! normal am\nt ( curr5t1 & ! armature is compell$ to r$uce its pull4 ,! effect is to cause ! two electrodes to aga9 approa* ea* o!r1 & 9 do+ s ! arc becomes bright]4 ,x w be se51 !re=e1 t !re is a con/ant fight betwe5 ! resi/ance coil & ! magnet1 ! comb9$ action ( ! two be+ su*1 t1 if prop]ly arrang$1 & ) p[]s 9 correct relation to ea* o!r1 ! light may be ma9ta9$ )\t undue flick]+4 ,su* devices are n[ univ]sally us$1 & !y af=d a /eady & reliable means ( illum9ation4 ,_m improvem5ts are made 9 ?is direction1 z well z 9 ! +r$i5ts ( ! electrodes4 ,a v novel device = assur+ a p]fect sep>ation at all times betwe5 ! electrodes1 is by means ( a pair ( p>allel c>bons1 held ap>t by a non-conductor su* z clay1 or "s mixture ( e>?1 a =m ( :i* is %[n 9 ,fig4 #aaf4 ,! draw+ %[s two electrodes1 sep>at$ by a non-conduct+ mat]ial1 :i* is ( su* a "* t x w break d[n & crumble away1 z ! ends ( ! electrodes burn away4 ,illu/ration3 ,fig4 #aaf4 ,p>allel ,c>bons4 ,?is device is admirable :]e ! alt]nat+ curr5t is us$1 because ! curr5t moves back & =?1 & ! two electrodes are ?us burn$ away at ! same rate ( spe$4 ,9 ! direct or cont9u\s curr5t ! movem5t is 9 "o direction only1 & z a result ! positive electrode is eat5 away twice z fa/ z ! negative4 ,?is is ! arc =m ( lamp univ]sally us$ = light+ l>ge spaces or areas1 su* z /reets1 railway /ations1 & ! l4 ,x is important also z ! means = utiliz+ se>*light illum9ation1 & frequ5tly = locomotive headlights4 ,arc lights are produc$ by :at is call$ ! s]ies curr5t4 ,?is means t ! lamps are all connect$ 9 a s+le l9e4 ,?is is illu/rat$ by ref]5ce to ,fig4 #aag1 9 :i* ,a repres5ts ! wire f ! dynamo1 & ,b1 ,c ! two electrodes1 %[+ ! curr5t pass+ ?r\gh f "o lamp to ! next4 ,illu/ration3 ,fig4 #aag4 ,arc-,light+ ,circuit4 ,a high voltage is necess>y 9 ord] to cause ! curr5t to leap across ! gap made by ! sep>ation ( ! electrodes4 ,,! ,,inc&esc5t ,,sy/em4--,?is me?od is entirely diff]5t f ! arc sy/em4 ,x has be5 /at$ t c]ta9 metals conduct electricity ) great] facility ?an o!rs1 & "s h high] resi/ance ?an o!rs4 ,if a c]ta9 am\nt ( electricity is =c$ ?r\gh "s metals1 !y w become heat$4 ,?is is true1 also1 if metals1 :i*1 ord9>ily1 w conduct a curr5t freely1 are made up into su* small conductors t x is difficult = ! curr5t to pass4 ,illu/ration3 ,fig #aah4 ,int]rupt$ ,conductor4 ,9 ! arc me?od high voltage is ess5tial2 9 ! inc&esc5t plan1 curr5t is ! important consid]ation4 ,9 ! arc1 ! light is produc$ by virtue ( ! break 9 ! l9e ( ! conductor2 9 ! inc&esc5t1 ! sy/em is clos$ at all times4 ,suppos+ we h a wire ,a1 a qu>t] ( an in* 9 diamet]1 c>ry+ a curr5t (1 say1 #ejj amp]es1 & at any po9t 9 ! circuit ! wire is made v small1 z %[n at ,b1 9 ,fig4 #aah1 x is obvi\s t ! small wire w\ld n be l>ge en\gh to c>ry ! curr5t4 ,! result w\ld be t ! small connection ,b w\ld heat up1 &1 f9ally1 be fus$4 ,:ile ! l>ge "p ( ! wire w\ld c>ry #ejj amp]es1 ! small wire c\ld n possibly c>ry m ?an1 say1 #aj amp]es4 ,n[ ^! little wires are ! filam5ts 9 an electric bulb1 & orig9ally ! attempt 0 made to h !m s connect$ up t !y c\ld be illum9at$ by a s+le wire1 z ) ! arc sy/em above expla9$1 "o foll[+ ! o!r z %[n 9 ,fig4 #aag4 ,illu/ration3 ,fig4 #aai4 ,inc&esc5t ,circuit4 ,x 0 discov]$1 h[ev]1 t ! addition ( ea* successive lamp1 s wir$1 w\ld n give light 9 proportion to ! addition1 b at only ab\t "o-f\r? ! illum9ation1 & su* a c\rse w\ld1 !re=e1 make electric light+ enorm\sly exp5sive4 ,?is k result$ 9 an entirely new sy/em ( wir+ up ! lamps 9 a circuit4 ,?is is expla9$ 9 ,fig4 #aai4 ,9 ?is figure ,a repres5ts ! dynamo1 ,b1 ,b ! bru%es1 ,c1 ,d ! two l9e wires1 ,e ! lamps1 & ,f ! %ort-circuit+ wires betwe5 ! two ma9 conductors ,c1 ,d4 ,x w be obs]v$ t ! wires ,c1 ,d are l>g] ?an ! cross wires ,f4 ,! object is to %[ t ! ma9 wires might c>ry a v heavy amp]age1 :ile ! small cross wires ,f require only a few amp]es4 ,?is is call$ ! multiple circuit1 & x is obvi\s t ! entire amp]age produc$ by ! dynamo w n be requir$ to pass ?r\gh ea* lamp1 b1 on ! o!r h&1 ea* lamp takes only en\gh necess>y to r5d] ! filam5t inc&esc5t4 ,?is inv5tion at once solv$ ! problem ( ! inc&esc5t sy/em & 0 call$ ! subdivision ( ! electric light4 ,by ?is means ! co/ 0 mat]ially r$uc$1 & ! wir+ up & in/allation ( lights mat]ially simplifi$4 ,b ! divisibility ( ! light did n1 by any means1 solve ! great problem t has occupi$ ! att5tion ( electricians & exp]im5t]s ev] s9ce4 ,! great "q 0 & is to pres]ve ! little filam5t :i* is heat$ to inc&esc5ce1 & f :i* we get ! light4 ,! ef=t ( ! curr5t to pass ?r\gh ! small filam5t meets ) su* a great resi/ance t ! sub/ance is heat$ up4 ,if x is made ( metal !re is a po9t at :i* x w fuse1 & ?us ! lamp is de/roy$4 ,x 0 f\nd t c>bon1 prop]ly treat$1 w\ld heat to a brilliant :ite heat )\t fus+1 or melt+1 s t ?is mat]ial 0 employ$4 ,b n[ foll[$ ano!r difficulty4 ,z ?is int5se heat consum$ ! p>ticles ( c>bon1 ow+ to ! pres5ce ( oxyg51 means 7 s\ght to exclude ! air4 ,?is 0 f9ally accompli%$ by mak+ a bulb ( glass1 f :i* ! air 0 exhau/$1 & z su* a globe _h no air to support combu/ion1 ! filam5ts 7 f9ally made s t !y w\ld la/ a long "t be=e be+ f9ally dis9tegrat$4 ,! que/ n[ is1 & has be51 to f9d "s mat]ial ( a purely metallic "*1 :i* w h a v high fus+ po9t1 & :i* w1 !re=e1 disp5se ) ! co/ ( ! exhau/$ bulb4 ,"s metals1 z = in/ance1 osmium1 tantalum1 ?orium1 & o!rs1 h be5 us$1 & o!rs1 also1 ) great success1 s t ! m>* ( improvem5ts is n[ go+ =w>d ) rapid /rides4 ,,vapor ,,lamps4--,"o ( ! directions 9 :i* consid]able en]gy has be5 direct$ 9 ! pa/1 0 to produce light f vapors4 ,! ,coop] ,hewitt m]cury vapor lamp is a tube fill$ ) ! vapor ( m]cury1 & a curr5t is s5t ?r\gh ! vapor :i* produces a gre5i% light1 & ow+ to t peculi> color1 has n met ) mu* success4 ,x is m]ely cit$ to %[ t !re are o!r directions ?an ! use ( metallic conductors & filam5ts :i* w produce light1 & ! day is no d\bt close at h& :5 we may expect "s important developm5ts 9 ! production ( light by means ( ! ,h]tzian waves4 ,,directions ,,= ,,improvem5ts4--,electricity1 h[ev]1 is n a *eap me?od ( illum9ation4 ,! enorm\s heat develop$ is l>gely wa/$4 ,! que/ ( ! inv5tor is to f9d a means :]eby light c be produc$ )\t ! g5]ation ( ! imm5se heat necess>y4 ,man has n yet f\nd a means :]eby he c make a heat )\t increas+ ! temp]ature1 z nature does x 9 ! gl[ worm1 or 9 ! firefly4 ,a c]ta9 electric en]gy w produce bo? light & heat1 b x is f\nd t mu* m ( ?is en]gy is us$ 9 ! heat ?an 9 ! light4 ,:at wond]ful possibilities are 9 /ore = ! inv5tor :o c make a heatless light6 ,x is a direction = ! ex]cise ( +5uity t w well repay any ef=ts4 ,curi\s ,sup]/itions ,conc]n+ ,electricity ,electricity1 z exhibit$ 9 light1 has be5 ! great m>vel ( all times4 ,! ^w electricity itself comes f ! ?und]bolt ( ! anci5t ,god ,zeus1 :i* is kn[n to be synonym\s ) ! ?und]bolt & ! lightn+4 ,magnetism1 :i* we "k to be only ano!r =m ( electricity1 0 n reg>d$ ! same z electricity by ! anci5ts4 ,iron :i* _h ! prop]ty to attract1 0 fir/ f\nd ne> ! t[n ( ,magnesia1 9 ,lydia1 & = t reason 0 call$ magnetism4 ,lat] on1 a glimm] ( ! tru? seem$ to dawn on ! e>ly sci5ti/s1 :5 !y saw ! resemblance betwe5 ! actions ( ! amb] & ! load/one1 z bo? attract$ p>ticles4 ,& "h ano!r curi\s ?+ result$4 ,amb] w attract p>ticles o!r ?an metals4 ,! magnet did n2 & f ?is imp]fect obs]vation & und]/&+1 grew a belief t electricity1 or magnetism w\ld attract all sub/ances1 ev5 human fle%1 & _m devices 7 made f magnets1 & us$ z cures = ! g\t1 & to affect ! bra91 or to remove pa94 ,ev5 z e>ly z #b1ejj ye>s be=e ! bir? ( ,*ri/ ! ,*9ese knew ( ! prop]ties ( ! magnet1 & also discov]$ t a b> ( ! p]man5t magnet w\ld arrange itself nor? & s\?1 l ! m>9]s' compass4 ,!re is no evid5ce1 h[ev]1 t x 0 us$ z a m>9]'s compass until c5turies aft]w>ds4 ,b ! matt] connect$ ) light1 z an electrical developm5t1 :i* int]e/s u1 is its manife/ations to ! anci5ts 9 ! =m ( lightn+4 ,! electricity ( ! e>? conc5trates itself on ! tops ( m\nta9s1 or 9 %>p peaks1 & acc\nts = ! magnific5t electrical displays always f\nd 9 m\nta9\s regions4 ,"s ye>s ago1 a not$ sci5ti/1 ,dr4 ,siem5s1 :ile /&+ on ! top ( ! great pyramid ( ,*eops1 9 ,egypt1 dur+ a /orm1 not$ t an electrical dis*>ge fl[$ f 8 h& :5 ext5d$ t[>d ! heav5s4 ,! curr5t manife/$ itself 9 su* a mann] t ! hiss+ noise 0 pla9ly p]ceptible4 ,! lit]ature ( all ages & ( all c\ntries %[s t ?is manife/ation ( electrical dis*>ges 0 not$1 & became ! subject ( discussions among le>n$ m54 ,all ^! displays 7 reg>d$ z ! bolts ( an angry ,god1 & hi/orians give _m acc\nts ( in/ances :]e1 9 ,8 ang]1 ,he s5t d[n ! lightn+ to de/roy4 ,among ! ,romans ,jupit] ?us hurl$ =? 8 wra?2 & among _m anci5t p1 ev5 d[n to ! "t ( ,*>lemagne1 any space /ruck by lightn+ 0 consid]$ sacr$1 & made consecrat$ gr\nd4 ,f ?is grew ! belief t x 0 sacrilegi\s to attempt to imitate ! lightn+ ( ! sky--t ,deity w\ld visit dire puni%m5t on any man :o attempt$ to produce an electric light4 ,virgil relates acc\nts :]e c]ta9 pr9ces attempt$ to imitate ! lightn+1 & 7 /ruck by ?und]bolts z puni%m5ts4 ,less ?an a c5tury ago ,b5jam9 ,frankl9 devis$ ! lightn+ rod1 9 ord] to prev5t lightn+ f /rik+ objects4 ,! lit]ature ( t day ab\nds ) in/ances ( prote/s made1 on ! "p ( ^? :o 7 z sup]/itions z ! p 9 anci5t times1 :o urg$ t x 0 impi\s to attempt to w>d (f ,heav5's lightn+s4 ,x 0 argu$ t ! lightn+ 0 "o way 9 :i* ! ,creator manife/$ ,8 displeasure1 & ex]cis$ ,8 p[] to /rike ! wick$4 ,:5 su* writ]s z ,pl9y w gravely set =? an explanation ( ! causes ( lightn+1 z foll[s 9 ! p>agraph bel[1 we c und]/& :y x inculcat$ sup]/iti\s fe>s 9 ! p ( anci5t times4 ,he says3 ,mo/ m5 are ignorant ( t secret1 :i*1 by close obs]vation ( ! heav5s1 deep s*ol>s & pr9cipal m5 ( le>n+ h f\nd out1 namely1 t !y are ! fires ( ! upp]mo/ planets1 :i*1 fall+ to ! e>?1 are call$ lightn+2 b ^? especially :i* are seat$ 9 ! middle1 t is ab\t ,jupit]1 p]haps because p>ticipat+ 9 ! excessive cold & moi/ure f ! upp] circle ( ,saturn1 & ! immod]ate heat ( ,m>s1 t is next b5ea?1 by ?is means he dis*>ges 8 sup]fluity1 & !re=e x is commonly said1 ',t ,jupit] %oote? & d>te? lightn+4' ,!re=e1 l z out ( a burn+ piece ( wood a coal flie? =? ) a crack1 ev5 s f a /> is spit out1 z x 71 & void$ =? ?is cele/ial fire1 c>ry+ ) x presages ( future ?+s2 s t ! heav5s %[e? div9e op]ations1 ev5 9 ^! p>cels & portions :i* are reject$ & ca/ away z sup]flu\s4 ,,*apt] ,,xvii ,,p[]1 ,,& ,,v>i\s ,,o!r ,,electrical ,,manife/ations ,x w\ld be difficult to m5tion any direction 9 human activity :]e electricity does n s]ve z an ag5t 9 "s =m or mann]4 ,man has le>n$ t ! ,creator gave ?is great p[] into ! h&s ( man to use1 & n to curse4 ,:5 ! dynamo 0 fir/ develop$ x did n appe> possible t x c\ld g5]ate electricity1 & !n use t electricity 9 ord] to turn ! dynamo 9 ! opposite direction4 ,x all seems s v natural to u n[1 t su* a ?+ %\ld practically foll[2 b man _h to le>n ?is4 ,let u try to make ! /atem5t pla9 by a few simple illu/rations4 ,by c>efully go+ ov] ! *apt] on ! mak+ ( ! dynamo1 x w be evid5t t ! basis ( ! g5]ation ( ! curr5t dep5ds on ! *ang+ ( ! direction ( ! fl[ ( an electric curr5t4 ,look at ! simple horse-%oe magnet4 ,if two ( !m are gradually mov$ t[>d ea* o!r1 s t ! nor? pole ( "o approa*es ! nor? pole ( ! o!r1 !re is a s5sible attempt = !m to pu% away f ea* o!r4 ,if1 h[ev]1 "o ( !m is turn$1 s t ! nor? pole ( "o is opposite ! s\? pole ( ! o!r1 !y w draw toge!r4 ,9 ?is we h ! f\ndation physical action ( ! dynamo & ! motor4 ,:5 p[] is appli$ to an armature1 & x moves ?r\gh a magnetic field1 ! action is j ! same z 9 ! case ( ! h& draw+ ! nor? & ! s\? pole ( ! two approa*+ magnets f ea* o!r4 ,! influ5ce ( ! electrical di/urbance produc$ by t act p]meat$ ! entire w9d+ ( ! field & armature1 & ext5d$ out on ! :ole l9e ) :i* ! dynamo 0 connect$4 ,9 ?is way a curr5t 0 e/abli%$ & transmitt$1 & ) prop] wires 0 s5t 9 ! =m ( circuits & di/ribut$ s z to d "w4 ,b an electric curr5t1 )\t suitable me*anism1 is ( no value4 ,x mu/ h me*anism to use x1 z well z to make x4 ,9 ! case ( light1 we h expla9$ h[ ! arc & ! inc&esc5t lamps utilize x = t purpose4 ,b n[1 attempt+ to get some?+ f x 9 ! way ( p[]1 means ano!r piece ( me*anism4 ,?is is done by ! motor1 & ?is motor is simply a conv]t]1 or a device = rev]s+ ! action ( ! electricity4 ,att5tion is call$ to ,figs4 #abj & #aba4 ,let u assume t ! field magnets ,a1 ,a are ! positives1 & ! magnets ,b1 ,b ! negatives4 ,! revolv+ armature has also f\r magnet coils1 two ( !m1 ,c1 ,c1 be+ positive1 & ! o!r two1 ,d1 ,d1 negative1 ea* ( ^! magnet coils be+ s connect$ up t !y w rev]se ! pol>ities ( ! magnets4 ,illu/ration3 ,figs4 #abj-aba4 ,,action ,,( ,,magnets ,,9 ,a ,,dynamo ,n[ 9 ! p>ticul> position ( ! revolv+ armature1 9 ,fig4 #abj1 ! magnets ( ! armature h j pass$ ! respective poles ( ! field magnets1 & ! belt ,e is compell$ to turn ! armature pa/ ! pole pieces by =ce 9 ! direction ( ! arr[ ,f4 ,aft] ! armature magnets h gone to ! positions 9 ,fig4 #aba1 ! positives ,a try to draw back ! negatives ,d ( ! armature1 & at ! same "t ! negatives ,b repel ! negatives ,d1 because !y are ( ! same pol>ities4 ,?is repulsion ( ! negatives ,a1 ,b cont9ues until ! armature poles ,c1 ,d h slightly pass$ !m1 :5 ! pol>ities ( ! magnets ,c1 ,d are *ang$2 s t x w be se51 by ref]5ce to ,fig4 #abb1 t ,d is n[ retreat+ f ,b1 & ,c is go+ away f ,a--t is1 be+ =c$ away contr>y to _! natural attractive influ5ces1 & 9 ,fig4 #abc1 :5 ! complete cycle is ne>ly f9i%$1 ! positives are aga9 approa*+ ea* o!r & ! negatives mov+ toge!r4 ,illu/ration3 ,figs4 #abb-abc4 ,,cycle ,,action ,,9 ,,dynamo ,9 ?is mann]1 at e po9t1 ! sets ( magnets are compell$ to move aga9/ _! magnetic pull4 ,?is expla9s ! dynamo4 ,n[ take up ! cycle ( ! motor1 & note 9 ,fig4 #abd t ! negative magnets ,d ( ! armature are closely approa*+ ! positive & negative magnets1 on "o side2 & ! positive magnets ,c are ne>+ ! positive & negatives on ! o!r side4 ,! positives ,a1 !re=e1 attract ! negatives ,d1 & ! negative ,b ex]t a pull on ! positives ,c at ! same "t4 ,! result is t ! armature is caus$ to revolve1 z %[n by ! d>t ,g1 9 a direction opposite to ! d>t 9 ,fig4 #abj4 ,illu/ration3 ,figs4 #abd-abe4 ,,action ,,( ,,magnets ,,9 ,,motor ,:5 ! pole pieces ( ! magnets ,c1 ,d are ab\t to pass magnets ,a1 ,b1 z %[n 9 ,fig4 #abe1 x is necess>y to *ange ! pol>ities ( ! armature magnets ,c1 ,d2 s t by ref]5ce to ,fig4 #abf1 x w be se5 t !y are n[ indicat$ z ,c-1 & ,d1 respectively1 & h mov$ to a po9t midway betwe5 ! poles ,a1 ,b 7z 9 ,fig4 #abe71 :]e ! pull on "o side1 & ! pu% on ! o!r are aga9 ! same1 & ! la/ ,figure #abg %[s ! cycle ne>ly complet$4 ,! %aft ( ! motor armature is n[ ! elem5t :i* turns ! me*anism :i* is to be op]at$4 ,to conv]t electrical impulses into p[]1 z ?us %[n1 results 9 great loss4 ,! fir/ /ep is to take ! /eam boil]1 :i* is ! fir/ /age 9 t s\rce :i* is ! mo/ common & univ]sal1 & by means ( fuel1 conv]t+ wat] into /eam4 ,! second is to use ! pressure ( ?is /eam to drive an eng9e2 ! ?ird is to drive ! dynamo :i* g5]ates ! electrical impulse2 & ! f\r? is ! conv]sion f ! dynamo into a motor %aft4 ,loss is met ) at ea* /ep1 & ! great problem is to elim9ate ?is wa/e4 ,illu/ration3 ,figs4 #abf-abg4 ,,positions ,,( ,,magnets ,,9 ,,motor ,! great advantage ( electrical p[] is n 9 utiliz+ x = consumption at close ranges1 b :]e x is desir$ to transmit x = long di/ances4 ,su* illu/rations may be f\nd 9 electric railways1 & :]e wat] p[] c be obta9$ z ! primal s\rce ( en]gy1 ! co/ is n excessive4 ,x is f\nd1 h[ev]1 t ev5 ) ! mo/ improv$ =ms ( me*anism1 9 electrical con/ruction1 ! int]nal combu/ion eng9es are f> m economical4 ,transmission ( ,en]gy ,"o ( ! great problems has be5 ! transmission ( ! curr5t to great di/ances4 ,by us+ a high voltage x may be s5t hundr$s ( miles1 b to use a curr5t ( t "* 9 ! c>s1 or %ops1 or homes1 w\ld be exce$+ly dang]\s4 ,to meet ?is requirem5t trans=m]s h be5 devis$1 :i* w take a curr5t ( v high voltage1 & deliv] a curr5t ( l[ t5sion1 & capable ( be+ us$ any:]e ) ! ord9>y motors4 ,,! ,,trans=m]4--,?is is an electrical device made up ( a core or cores ( ?9 %eet metal1 ar\nd :i* is w\nd sets ( insulat$ wires1 "o set be+ design$ to receive ! high voltage1 & ! o!r set to put out ! l[ voltage1 z describ$ 9 a =m] *apt]4 ,^! may be made :]e ! orig9al output is a v high voltage1 s t !y w be /epp$ d[n1 fir/ f "o voltage to a l[]1 & !n f t to ! next l[] /age4 ,?is is call$ ! ,/ep d[n trans=m]1 & is n[ us$ ov] ! entire _w1 :]e l>ge voltages are g5]at$4 ,,electric ,,furnaces4--,! mo/ important developm5t ( electricity 9 ! direction ( heat is its use 9 furnaces4 ,z be=e /at$1 an int5se heat is capable ( be+ g5]at$ by ! electric curr5t1 s t x becomes ! great ag5t to use = ! treatm5t ( refractory mat]ial4 ,9 furnaces ( ?is k9d ! electric arc is ! me*anical =m us$ to produce ! great heat1 ! only diff]5ce be+ 9 ! size ( ! app>atus4 ,! electric furnace is simply an imm5se =m ( arc light1 capable ( tak+ a high voltage1 & su* an arc is enclos$ )9 a suitable ov5 ( refractory mat]ial1 :i* /ill fur!r cons]ves ! heat4 ,,weld+ ,,by ,,electricity4--,! next /ep is to use ! high heat ?us capable ( be+ produc$1 to fuse metals s t !y may be weld$ toge!r4 ,x is a difficult matt] to unite two l>ge pieces ( metal by ! =g+ me?od1 because ! highe/ heat is requir$1 ow+ to _! bulk1 & 9 addition imm5se hamm]s1 weigh+ tons1 mu/ be employ$4 ,electric weld+ (f]s a simple & easy me?od ( accompli%+ ! result1 & 9 ! do+ ( :i* x avoids ! oxidiz+ action ( ! =g+ heat4 ,in/ead ( heat+ ! pieces to be weld$ 9 a =ge1 z is n[ done1 ! ends to be unit$ are simply br\ght into contact1 & ! curr5t is s5t ?r\gh ! ends until !y are 9 a s(t condition1 aft] :i* ! p>ts are press$ toge!r & unit$ by ! simple m]g+ ( ! pla/ic condition 9 :i* !y are r$uc$ by ! high electric heat4 ,?is =m ( weld+ makes ! mo/ p]fect jo9t1 & requires no hamm]+1 z ! mass ( ! metal fl[s f "o "p or end to ! o!r2 ! unity is a p]fect "o1 & ! advantage is t ! metals c be kept 9 a semi-fluid /ate = a consid]able "t1 ?us assur+ a p]fect admixture ( ! two p>ts4 ,) ! ord9>y =m ( weld+ x is necess>y to drive ! heat$ p>ts toge!r )\t any delay1 & at ! lea/ cool+ mu/ be reheat$1 or ! jo9t w n be p]fect4 ,! smalle/ k9ds ( electric heat+ app>atus are n[ be+ made1 s t small articles1 %eet metal1 small rods1 & l p>ts c be unit$ ) ! greate/ facility4 ,,*apt] ,,xviii ,x-,,ray1 ,,radium1 ,,& ,,! ,,l ,! cam]a sees ?+s invisible to ! human eye4 ,its mo/ effective "w is done ) beams :i* are beyond human p]ception4 ,! photograph] uses ! ,act9ic rays4 ,ord9>y light is compos$ ( ! sev5 prim>y colors1 ( :i* ! l[e/ 9 ! scale is ! r$1 & ! highe/ to violet4 ,^? bel[ ! r$ are call$ ! ,infra-r$1 & !y are ! ,h]tzian waves1 or ^? us$ 9 wireless telegraphy4 ,^? above ! violet are call$ ,ultra-violet1 & ^! are employ$ = ,x-ray "w4 ,! =m] are produc$ by ! high t5sion electric app>atus1 :i* we h describ$ 9 ! *apt] relat+ to wireless telegraphy2 & ! latt]1 call$ also ! ,ro5tg5 rays1 are g5]at$ by ! ,crookes' ,tube4 ,?is is a tube f :i* all ! atmosph]e has be5 extract$ s t x is a practical vacuum4 ,)9 ?is are plac$ electrodes s z to div]t ! action ( ! electrical dis*>ge 9 a p>ticul> direction1 & ?is light1 :5 dis*>g$1 is ( su* a peculi> "* t its discov]y made a s5sation 9 ! sci5tific _w4 ,! reason = ?is great wond] 0 n 9 ! fact t x project$ a light1 b because ( its "*4 ,ord9>y light1 z we see x ) ! eye1 is capable ( be+ reflect$1 z :5 we look into a mirror at an angle4 ,! ,x-ray w n reflect1 b in/ead1 pass directly ?r\gh ! glass4 ,!n1 ord9>y light is capable ( refraction4 ,?is is %[n by a ray ( light b5d+ z x passes ?r\gh a glass ( wat]1 :i* is notic$ :5 ! light is at an angle to ! surface4 ,! ,x-ray w pass ?r\gh ! wat] )\t be+ *ang$ f a /raight l9e4 ,! =ego+ be+ ! case1 x 0 b a simple /ep to conclude t if x 7 possible to f9d a means :]eby ! human eye c\ld see )9 ! ultra-violet beam1 x w\ld be possible to see ?r\gh opaque sub/ances4 ,f ! discov]y s important & f> rea*+ x 0 n long until x 0 f\nd t if ! ultra-violet rays1 ?us propagat$1 7 transmitt$ ?r\gh c]ta9 sub/ances1 _! rates ( vibration w\ld be br\ght d[n to ! spe$s :i* s5d =? ! visible rays1 & n[ ! eye is able to see1 9 a measure at lea/1 :at ! act9ic rays %[4 ,?is discov]y 0 b ! =]unn] ( a /ill m important developm5t1 namely1 ! discov]y ( radium4 ,! actual f9d+ ( ! metal 0 prec$$ by ! k t c]ta9 m9]als1 & wat]1 z well1 possess$ ! prop]ty ( radio-activity4 ,radio-activity is a ^w us$ to express t quality 9 metals or o!r mat]ial by means ( :i* obscure rays are emitt$1 t h ! capacity ( dis*>g+ electrifi$ bodies1 & ! p[] to ionize gases1 z well z to actually affect photograph plates4 ,c]ta9 metals _h ?is prop]ty to a rem>kable degree1 p>ticul>ly uranium1 ?orium1 polonium1 act9ium1 & o!rs1 & 9 #ahih ! ,curies1 husb& & wife1 ,fr5* *emi/s1 isolat$ an elem5t1 v ductile 9 its "*1 :i* 0 a :ite metal1 & _h a mo/ brilliant lu/]4 ,pit*bl5de1 ! base metal f :i* ?is 0 extract$1 0 discov]$ to be highly radio-active1 & on mak+ te/s ( ! product tak5 f x1 !y 7 surpris$ to f9d t x emitt$ a =m ( en]gy t f> exce$$ 9 calculations any computations made on ! basis ( radio-activity 9 ! metals hi!rto exam9$4 ,b ?is 0 n ! mo/ rem>kable "p ( ! developm5ts4 ,! en]gy1 :atev] x 01 _h ! p[] to *ange _m o!r sub/ances if br\ght into close proximity4 ,x d>k5s ! color ( diamonds1 qu>tz1 mica1 & glass4 ,x *anges "s ( ! latt] 9 color1 "s k9ds be+ turn$ to br[n & o!rs into violet or purple t+es4 ,radium has ! capacity to r$d5 ! sk91 & affect ! fle% ( p]sons1 ev5 at "s consid]able di/ance1 & x is a mo/ p[]ful g]micide1 de/roy+ bact]ia1 & has be5 f\nd also to produce "s rem>kable cures 9 diseases ( a canc]\s nature4 ,! rem>kable simil>ity ( ! rays propagat$ by ?is sub/ance1 ) ! ,x-rays1 lead _m to believe t !y are electrical 9 _! "*1 & ! :ole sci5tific _w is n[ /riv+ to use ?is sub/ance1 z well z ! m famili> light waves ( ! ,ro5tg5 tube1 9 ! heal+ ( diseases4 ,x is n at all rem>kable t ?is use ( x %\ld fir/ be consid]$1 z x has be5 ! hi/ory ( ! electrical developm5ts1 f ! e>lie/ times1 t ea* successive /age %\ld f9d advocates :o w\ld urge its virtues to heal ! sick4 ,x 0 s :5 ! dynamo 0 inv5t$1 :5 ! high t5sion curr5t 0 produc$2 & electrical !rapeutics became a lead+ !me :5 transmission by induction became recogniz$ z a sci5tific fact4 ,x is n _m ye>s s9ce ! ,x-rays 7 discov]$1 & ! fir/ ann\ncem5t 0 conc]n+ its wond]ful heal+ p[]s4 ,?is 0 p>ticul>ly true 9 ! case ( radium1 b = "s reason1 aft] ! fir/ te/s1 all exp]im5t]s 7 ?w>t$ 9 _! !ories1 because ! sci5ce1 l all o!rs1 requir$ inf9ite pati5ce & exp]i5ce4 ,x 0 discov]$1 9 ! case ( ! ,x-ray1 t x mu/ be us$ 9 a modifi$ =m1 & accord+ly1 v>i\s modifications ( ! waves 7 introduc$1 call$ ! m & ! n rays1 z well z _m o!rs1 ea* hav+ "s peculi> qualification4 ,9 "t1 no d\bt1 ! inve/igators w f9d ! "r quality = ea* disease1 & le>n h[ to apply x4 ,?us1 electricity1 t mo/ allur+ ?+ :i*1 9 itself1 _c be se51 & is ( su* a "* t x _c ev5 be def9$ 9 t]ms :i* w suit ! exact sci5tific m9d1 is daily br++ new wond]s = our inve/igation & use4 ,x is1 inde$1 a /udy :i* is s broad t x has no limitations1 & a field :i* nev] w be exhau/$4 ,,! ,,end ,,gloss>y ,,( ,,words ,,us$ ,,9 ,,text ,,( ,,?is ,,volume ,acid4 ,accumulator mat]ial is sulphuric acid1 dilut$ ) wat]4 ,active ,t "p ( ! mat]ial 9 accumulator plates ,mat]ial4 :i* is act$ ^u by ! electric curr5t4 ,accumulator4 ,a cell1 g5]ally kn[n z a /orage batt]y1 :i* :ile x initially receives a *>ge ( electricity1 is nev]!less1 ( su* a "*1 ow+ to ! active mat]ial ( :i* x is made1 t x accumulates1 or1 z x 71 g5]ates electricity4 ,a]ial ,wire1 ,! wire :i*1 9 wireless telegraphy1 is c>ri$ or ,conductor4 up into ! air to connect ! ant5n ) ! receiv+ & s5d+ app>atus4 ,al>m1 ,burgl>4 ,a circulat+ sy/em 9 a build+1 connect$ up ) a bell or o!r signal+ means4 ,alloy4 ,a mixture ( two or m metals2 z copp] & z9c to make brass2 nickel & z9c to =m ,g]man silv]4 ,alt]nat+ ,curr5t4 ,a curr5t :i* goes back & =? 9 opposite directions1 unlike a direct curr5t :i* fl[s cont9u\sly 9 "o direction ov] a wire4 ,alt]nation4 ,! t]m appli$ to a *ange 9 ! direction ( an alt]nat+ curr5t1 ! frequ5cy ( ! alt]nations rang+ up to #bj1jjj or m vibrations p] second4 ,amb]4 ,a res91 yell[ 9 color1 :i* :5 rubb$ ) a clo?1 becomes excit$ & gives =? negative electricity4 ,ammet]4 ,an in/rum5t = measur+ ! quantity or fl[ ( electricity4 ,amp]e4 ,! unit ( curr5t2 ! t]m 9 :i* /r5g? ( ! curr5t is measur$4 ,an amp]e is an electromotive =ce ( "o volt ?r\gh a resi/ance ( "o ohm4 ,annunciator4 ,a device :i* indicates or signals a call giv5 f "s di/ant po9t4 ,anode4 ,! positive t]m9al 9 a conduct+ circuit1 l ! t]m9al ( ! c>bon plate 9 a batt]y4 ,x is a plate 9 an electroplat+ ba? f :i* ! curr5t goes ov] to ! ca?ode or negative plate or t]m9al4 ,arc4 ,a t]m employ$ to designate ! gap1 or ! curr5t :i* fl[s across betwe5 ! conductors1 l ! space betwe5 ! two c>bons ( an arc lamp1 :i* gives ! light4 ,armature4 ,a body ( iron1 or o!r suitable metal1 :i* is 9 ! magnetic field ( a magnet4 ,armature ,b>4 ,! piece :i* holds ! armature4 ,also "o ( a s]ies ( b>s :i* =m ! conductors 9 armature w9d+s4 ,armature ,coil4 ,! w9d+ ar\nd an armature1 or ar\nd ! core ( an armature4 ,armature ,core4 ,! "p 9 a dynamo or motor :i* revolves1 & on :i* ! wire coils are w\nd4 ,a/atic 7,galvanomet]74 ,t :i* has no magnetic action to direct or div]t any?+ ext]ior to x4 ,atom4 ,! ultimate p>ticle ( an elem5t>y sub/ance4 ,attraction4 ,t prop]ty ( matt] :i* causes p>ticles to adh]e1 or coh]e1 to ea* o!r4 ,x is kn[n "u a v>iety ( t]ms1 su* z gravitation1 *emical aff9ity1 electro-magnetism & dynamic attraction4 ,automatic ,cut-out4 ,a device :i* acts ?r\gh ! op]ation ( ! me*anism ) :i* x is connect$4 ,x is usually appli$ to a device :i* cuts out a curr5t :5 x ov]*>ges or ov]loads ! wire4 ,ba?4 ,9 electroplat+1 ! vessel or tank :i* holds ! electroplat+ solution4 ,batt]y4 ,a comb9ation ( two or m cells4 ,batt]y1 ,dry4 ,a prim>y batt]y 9 :i* ! electrolyte is made 9 a solid =m4 ,batt]y1 ,galvanic4 ,a batt]y :i* is bett] kn[n by ! "n ( ! ,voltaic ,pile1 made up ( z9c & copp] plates :i* alt]nate1 & ) a lay] ( acidulat$ pap] betwe5 ea* pair ( plates4 ,batt]y1 ,/orage4 ,a batt]y :i* accumulates electricity g5]at$ by a prim>y batt]y or a g5]ator4 ,bru%4 ,a t]m appli$ to ! conduct+ m$ium t be>s aga9/ ! cyl9drical surface ( a commutator4 ,buzz]4 ,an electric call produc$ by a rapidly mov+ armature ( an electro-magnet4 ,cable4 ,a numb] ( wires or conductors assembl$ 9 "o /r&4 ,c&le-p[]4 ,! am\nt ( light giv5 by ! legal-/&>d c&le4 ,?is /&>d is a sp]m c&le1 :i* burns two gra9s a m9ute4 ,capacity4 ,! c>ry+ p[] ( a wire or circuit1 )\t heat+4 ,:5 heat$ !re is an ov]load1 or ! capacity ( ! wire is ov]tax$4 ,capacity1 ,/orage4 ,! quantity ( electricity 9 a second>y batt]y :5 fully *>g$1 usually reckon$ 9 amp]e h\rs4 ,c>bon4 ,a mat]ial1 l coke1 gr\nd or cru%$1 & =m$ into /icks or plates by mold+ or compression4 ,x requires a high heat to melt or burn1 & is us$ z electrodes = arc lamps & = batt]y elem5ts4 ,x has poor conductivity1 & = arc lamps is coat$ ) copp] to increase its conductivity4 ,cell1 ,electrolytic4 ,a vessel conta9+ an electrolyte = electroplat+ purposes4 ,*>ge4 ,! quantity ( electricity on ! surface ( a body or conductor4 ,*emical ,*ange4 ,:5 a curr5t passes ?r\gh electrodes 9 a solution1 a *ange takes place :i* is *emical 9 its "*4 ,add+ sulphuric acid to wat] produces heat4 ,if electrodes ( opposite pol>ity are plac$ 9 su* an acid solution1 a *emical *ange is produc$1 :i* is trans=m$ into electricity4 ,*ok+ ,coil4 ,an in/rum5t 9 a circuit :i* by a =m ( resi/ance regulates ! fl[ ( ! curr5t1 or returns "p ( x to ! s\rce ( its g5]ation4 ,c\nt]-electromotive ,=ce4 ,cells :i* are ins]t$ 9 opposition to a batt]y to r$uce high voltage4 ,circuit1 ,a/atic4 ,a circuit 9 an in/rum5t s w\nd t ! e>?'s magnetism w n affect x4 ,circuit ,break]4 ,any in/rum5t 9 a circuit :i* cuts out or int]rupts ! fl[ ( a curr5t4 ,circuit1 ,ext]nal4 ,a curr5t fl[s ?r\gh a wire or conductor1 & also along ! air outside ( ! conductor1 ! latt] be+ ! ext]nal circuit4 ,circuit ,indicator4 ,an in/rum5t1 l a galvanomet]1 t %[s ! direction 9 :i* a curr5t is fl[+ ?r\gh a conductor4 ,circuit1 ,return4 ,usually ! gr\nd return1 or ! negative wire f a batt]y4 ,circuit1 ,%ort4 ,any connection betwe5 ! ma9s or p>allel l9es ( a circuit :i* does n g ?r\gh ! app>atus = :i* ! circuit is int5d$4 ,coh]]4 ,a tube1 or o!r /ructure1 conta9+ normally high resi/ance p>ticles :i* =m a pa? or bridge betwe5 ! opposite t]m9als ( a circuit4 ,coil4 ,a wire1 usually insulat$1 w\nd ar\nd a spool4 ,coil1 ,induction4 ,"o ( a pair ( coils design$ to *ange ! voltage ( a curr5t ( electricity1 f a high] to a l[]1 or f a l[] to a high] electro-motive =ce4 ,coil1 ,resi/ance4 ,a coil s w\nd t x w (f] a resi/ance to a /eady curr5t1 or r$uce ! fl[ ( electricity4 ,commutator4 ,a cyl9d] on ! end ( ! armature ( a dynamo or motor & provid$ ) a pair ( contact plates = ea* p>ticul> coil 9 ! armature1 9 ord] to *ange ! direction ( ! curr5t4 ,compass4 ,an app>atus :i* indicates ! direction or fl[ ( ! e>?'s magnetism4 ,cond5s]4 ,a device = /or+ up electro-/atic *>ges4 ,conductance4 ,t quality ( a conductor to c>ry a curr5t ( electricity1 dep5d5t on its %ape = ! be/ results4 ,conduction4 ,! transmission ( a curr5t ?r\gh a rod1 wire or conductor4 ,conductivity4 ,t quality :i* has ref]5ce to ! capacity to conduct a curr5t4 ,conductor4 ,any body1 su* z a b>1 rod1 wire1 or ma*9e1 :i* w c>ry a curr5t4 ,connector4 ,a b9d+ po/1 clamp1 screw1 or o!r means to hold ! end ( a wire1 or electric conductor4 ,contact4 ,to unite any p>ts 9 an electric circuit4 ,controll]4 ,! h&le ( a swit*bo>d1 or o!r contact mak+ & break+ means 9 a circuit4 ,conv]t]4 ,an induction coil 9 an alt]nat+ circuit = *ang+ pot5tial diff]5ce1 su* z high alt]nat+ voltage into l[ direct curr5t voltage4 ,convolution4 ,to w9d l a clock spr+4 ,core4 ,! inn] portion ( an electro-magnet4 ,! inside "p ( an armature w\nd ) wire4 ,core1 ,lam9at$4 ,:5 ! core is built up ( a numb] ( sep>ate pieces ( ! same mat]ial1 b n insulat$ f ea* o!r4 ,c\lomb4 ,! unit ( electrical quantity4 ,x is ! quantity pass$ by a curr5t ( "o amp]e int5sity 9 "o second ( "t4 ,c\ple1 ,electric4 ,two or m electrodes 9 a liquid to produce an electric =ce4 ,curr5t1 ,alt]nat+4 ,a natural curr5t produc$ by ! action ( electro-magnets4 ,x is a succession ( %ort impulses 9 opposite directions4 ,curr5t1 ,con/ant4 ,a curr5t :i* is uni=mly ma9ta9$ 9 a /eady /ream4 ,curr5t1 ,induc$4 ,a curr5t produc$ by electro-dynamic induction4 ,curr5t ,met]4 ,an app>atus = indicat+ ! /r5g? ( a curr5t4 ,an ammet]4 ,curr5t1 ,oscillat+4 ,a curr5t :i* p]iodically alt]nates4 ,curr5t1 ,p]iodic4 ,a p]iodically v>y+ curr5t /r5g?4 ,curr5t1 ,undulat+4 ,a curr5t :i* has a con/ant direction1 b has a cont9u\sly v>y+ /r5g?4 ,decomposition4 ,! sep>ation ( a liquid1 su* z an electrolyte1 into its prime elem5ts1 ei!r electrically or o!rwise4 ,deflection4 ,! *ange ( movem5t ( a magnetic ne$le out ( its regul> direction ( movem5t4 ,demagnetization4 ,:5 a curr5t passes ?r\gh a coil w\nd on an iron core1 ! core becomes magnetiz$4 ,:5 ! curr5t ceases ! core is no long] a magnet4 ,x is !n said to be demagnetiz$4 ,x also has ref]5ce to ! process = mak+ a wat* non-magnetic s t x w n be affect$ :5 9 a magnetic field4 ,d5sity4 ,! quantity ( an electric *>ge 9 a conductor or sub/ance4 ,depol>ization4 ,! removal ( magnetism f a p]man5t magnet1 or a horse-%oe magnet1 = in/ance4 ,x is g5]ally accompli%$ by apply+ heat4 ,deposition1 ,! act ( c>ry+ metal f "o pole ( a cell to ,electrolysis4 ano!r pole1 z 9 electroplat+4 ,detector4 ,me*anism = indicat+ ! pres5ce ( a curr5t 9 a circuit4 ,diaphragm4 ,a plate 9 a telephone1 :i*1 9 ! receiv]1 is 9 ! magnetic field ( a magnet1 & 9 a transmitt] c>ries ! light contact po9ts4 ,dielectric4 ,a non-conductor = an electric curr5t1 b ?r\gh :i* electro-/atic induction w take place4 ,= example3 glass & rubb] are dielectrics4 ,dis*>ge4 ,! curr5t fl[+ f an accumulator4 ,dis9tegration4 ,! break+ up ( ! plate or active mat]ial4 ,disruptive4 ,a /atic dis*>ge pass+ ?r\gh a dielectric4 ,duplex ,wire4 ,a pair ( wires usually twi/$ toge!r & insulat$ f ea* o!r to =m ! conduct+ circuit ( a sy/em4 ,dynamic ,electricity4 ,! t]m appli$ to a curr5t fl[+ ?r\gh a wire4 ,dynamo4 ,an app>atus1 consi/+ ( core & field magnets1 :i*1 :5 ! core is turn$1 w develop a curr5t ( electricity4 ,e>? ,returns4 ,in/ead ( us+ two wires to c>ry a circuit1 ! e>? is us$ = :at is call$ ! return circuit4 ,effici5cy4 ,! total electrical en]gy produc$1 9 :i* t wa/$1 z well z t us$1 is calculat$4 ,ela/icity4 ,t prop]ty ( any matt] :i*1 aft] a /ress1 w cause ! sub/ance to return to its orig9al =m or condition4 ,electricity has ela/icity1 :i* is utiliz$ 9 cond5s]s1 z an in/ance4 ,electricity1 ,lightn+1 &1 9 %ort1 any curr5t or electrical ,atmosph]ic4 impulse1 l wireless telegraphic waves1 is call$ atmosph]ic4 ,electricity1 ,electricity ) a l[ pot5tiality & l>ge curr5t ,voltaic4 d5sity4 ,electrification4 ,! process ( imp>t+ a *>ge ( electricity to any body4 ,electro-*emi/ry4 ,! /udy ( :i* treats ( electric & *emical =ces1 su* z electric plat+1 electric fus+1 electrolysis1 & ! l4 ,electrode4 ,! t]m9als ( a batt]y1 or ( any circuit2 z1 = in/ance1 an arc light4 ,electrolyte4 ,any mat]ial :i* is capable ( be+ decompos$ by an electric curr5t4 ,electro-magnetism4 ,magnetism :i* is creat$ by an electric curr5t4 ,electromet]4 ,an in/rum5t = measur+ /atic electricity1 diff]+ f a galvanomet]1 :i* measures a curr5t 9 a wire t acts on ! magnetic ne$le ( ! galvanomet]4 ,electro-motive ,voltage1 :i* is ! measure or unit ( e4 m4 f4 ,=ce4 7,e4 ,m4 ,f47 ,electroscope4 ,a device = indicat+ n only ! pres5ce ( electricity1 b :e!r x is positive or negative4 ,electro-/atic ,surfaces sep>at$ by a dielectric = opposite ,accumulator4 *>g+ ( ! surface4 ,elem5t4 ,9 electricity a =m ( matt]1 z1 = in/ance1 gold1 or silv]1 t has no o!r matt] or comp\nd4 ,orig9al elem5ts _c be sep>at$1 because !y are n made up ( two or m elem5ts1 l brass1 = in/ance4 ,excessive ,*>ge4 ,a /orage batt]y *>g$ at too high a rate4 ,excessive ,dis*>ge4 ,a /orage batt]y dis*>g$ at too high a rate4 ,excessive ,ov]*>ge4 ,*>g+ = too long a "t4 ,excit]4 ,a g5]ator1 ei!r a dynamo or a batt]y1 = excit+ ! field ( a dynamo4 ,exhau/ive ,dis*>ge4 ,an excessive ov]-dis*>ge ( an accumulator4 ,f4 ,! sign us$ to indicate ! heat t]m ,fahr5heit4 ,fall ( ,voltage4 ,! diff]5ce betwe5 ! initial & ! f9al voltage 9 a curr5t4 ,field4 ,! space or region ne> a magnet or *>g$ wire4 ,also ! electro-magnets 9 a dynamo or motor4 ,fl[4 ,! volume ( a curr5t go+ ?r\gh a conductor4 ,=ce1 ,electro-magnetic4 ,! pull develop$ by an electro-magnet4 ,frictional ,a curr5t produc$ by rubb+ dissimil> ,electricity4 sub/ances toge!r4 ,full ,load4 ,! greate/ load a batt]y1 accumulator or dynamo w su/a94 ,galvanic4 ,p]ta9+ to ! electro-*emical relations ( metals t[>d ea* o!r4 ,galvaniz+4 ,! art ( coat+ "o metal ) ano!r1 su*1 = in/ance1 z imm]s+ iron 9 molt5 z9c4 ,galvanometry4 ,an in/rum5t hav+ a p]man5tly magnetiz$ ne$le1 :i* is influ5c$ by a coil or a wire 9 close proximity to x4 ,galvanoscope4 ,an in/rum5t1 l a galvanomet]1 :i* det]m9es :e!r or n a curr5t is pres5t 9 a te/$ wire4 ,g5]ator4 ,a t]m us$ to g5]ally indicate any device :i* orig9ates a curr5t4 ,g]man ,silv]4 ,an alloy ( copp]1 nickel & z9c4 ,graphite4 ,"o =m ( c>bon4 ,x is made artificially by ! electric curr5t4 ,grid4 ,! metallic frame ( a plate us$ to hold ! active mat]ial ( an accumulator4 ,gravity4 ,! attraction ( mass = mass4 ,weight4 ,! accel]at+ t5d5cy ( mat]ial to move t[>d ! e>?4 ,gutta ,p]*a4 ,ca\t*\c1 :i* has be5 treat$ ) sulphur1 to h>d5 x4 ,x is produc$ f ! sap ( tropical trees1 & is a good insulator4 ,h>monic ,receiv]4 ,a vibrat+ re$ act$ on by an electro-magnet1 :5 tun$ to its pit*4 ,high ,e4 ,m4 ,f4 ,a t]m to indicate curr5ts :i* h a high voltage1 & usually l[ amp]age4 ,ignit]4 ,me*anism compos$ ( a batt]y1 induction coil & a vibrator1 = mak+ a jump sp>k1 to ignite gas1 p[d]1 etc4 ,i4 ,h4 ,p4 ,abbreviation1 :i* means ,indicat$ ,horse ,p[]4 ,impulse4 ,a sudd5 motion ( "o body act+ aga9/ ano!r4 ,an electro-magnetic wave magnetiz+ s(t iron1 & ?is iron attract+ ano!r piece ( iron1 z an example4 ,inc&esc5ce1 ,a conductor heat$ up by a curr5t s x w ,electric4 gl[4 ,induc$ ,curr5t4 ,a curr5t ( electricity :i* sets up l9es ( =ce at "r angles to ! body ( ! wire ?r\gh :i* ! curr5t is transmitt$4 ,induction1 ,magnetic4 ,a body )9 a magnetic field :i* is excit$ by ! magnetism4 ,in/allation4 ,ev]y?+ belong+ to an equipm5t ( a build+1 or a circuit+ sy/em to d a c]ta9 ?+4 ,insulation4 ,a mat]ial or sub/ance :i* resi/s ! passage ( a curr5t plac$ ar\nd a conductor4 ,int5sity4 ,! /r5g? ( a magnetic field1 or ( a curr5t fl[+ ov] a wire4 ,int]nal ,resi/ance4 ,! curr5t /r5g? ( electricity ( a wire to resi/ ! passage4 ,int]rupt]4 ,a device 9 a wire or circuit = *eck+ a curr5t4 ,x also ref]s to ! vibrator ( an induction coil4 ,jo9t4 ,! place :]e two or m conductors are unit$4 ,jo9t ,resi/ance4 ,! comb9$ resi/ance (f]$ by two or m sub/ances or conductors4 ,jump ,sp>k4 ,a sp>k1 disruptive 9 its "*1 betwe5 two conduct+ po9ts4 ,initial ,*>ge4 ,! *>ge requir$ to />t a batt]y4 ,ka?ode1 or ,ca?ode4 ,! negative plate or side ( a batt]y4 ,! plate on :i* ! electro deposit is made4 ,key4 ,! arm ( a telegraph s\nd]4 ,a b> ) a f+] piece1 :i* is h+$ & s arrang$ t x w make & break contacts 9 an electric circuit4 ,keybo>d4 ,a swit*-bo>d2 a bo>d on :i* is m\nt$ a numb] ( swit*es4 ,kil[att4 ,a unit1 repres5t+ #a1jjj watts4 ,an electric curr5t measure1 usually express$ ?us3 ,k4,w4 ,kil[att ,h\r4 ,! computation ( "w equal to ! ex]tion ( "o kil[att 9 "o h\r4 ,knife ,swit*4 ,a b> ( a blade-l =m1 adapt$ to move d[n betwe5 two f+]s1 & ?us e/abli% metallic connections4 ,lam9at$4 ,made up ( ?9 plates ( ! same mat]ial1 laid toge!r1 b n insulat$ f ea* o!r4 ,lamp ,arc4 ,a voltaic arc lamp1 us+ c>bon electrodes1 ) me*anism = fe$+ ! electrodes regul>ly4 ,lamp1 ,inc&esc5t4 ,a lamp ) a filam5t heat$ up to a gl[ by ! action ( an electric curr5t4 ,! filam5t is )9 a vacuum 9 a glass globe4 ,leak4 ,loss ( electrical en]gy ?r\gh a fault 9 wir+1 or 9 us+ b>e wires4 ,load4 ,! amp]e curr5t deliv]$ by a dynamo "u c]ta9 conditions4 ,l[ ,frequ5cy4 ,a curr5t 9 :i* ! vibrations are ( few alt]nations p] second4 ,magnet4 ,a metallic sub/ance :i* has p[] to attract iron & /eel4 ,magnet ,b>4 ,a /raight piece ( metal4 ,magnet ,coil4 ,a coil ( wire1 insulat$1 surr\nd+ a core ( iron1 to receive a curr5t ( electricity4 ,magnet ,core4 ,a b> ( iron adapt$ to receive a w9d+ ( wire4 ,magnet1 ,field4 ,a magnet 9 a dynamo4 ,a motor to produce electric en]gy4 ,magnet1 ,p]man5t4 ,a %ort /eel =m1 to hold magnetism = a long "t4 ,magnetic ,adh]5ce4 ,! adh]5ce ( p>ticles to ! poles ( a magnet4 ,magnetic ,t quality ( a metal :i* draws metals4 ,also ,attraction & ! pull+ action ( unlike poles = ea* ,repulsion4 o!r1 & pu%+ away ( l poles :5 br\ght toge!r4 ,magnetic ,=ce4 ,! action ex]cis$ by a magnet ( attract+ or repell+4 ,magnetic ,pole4 ,! e>? has ,nor? & ,s\? magnetic poles4 ,! s\? pole ( a magnetic ne$le is attract$ s x po9ts to ! nor? magnetic pole2 & ! nor? pole ( ! ne$le is attract$ to po9t to ! s\? magnetic pole4 ,magneto-g5]ator4 ,a p]man5t magnet & a revolv+ armature = g5]at+ a curr5t4 ,maximum ,voltage4 ,! f9al voltage aft] *>g+4 ,molecule4 ,invisible p>ticles made up ( two or m atoms ( diff]5t matt]4 ,an atom is a p>ticle ( "o sub/ance only4 ,morse ,s\nd]4 ,an electric in/rum5t design$ to make a click+ s\nd1 :5 ! armature is drawn d[n by a magnet4 ,motor-dynamo4 ,a motor & a dynamo hav+ _! armatures connect$ toge!r1 :]eby ! motor is driv5 by ! dynamo1 s z to *ange ! curr5t into a diff]5t voltage & amp]age4 ,motor-trans=m]4 ,a motor :i* deliv]s ! curr5t l a g5]ator4 ,ne$le4 ,a b> magnet horizontally pois$ on a v]tical pivot po9t1 l ! ne$le ( a m>9]'s compass4 ,negative ,amb]1 :5 rubb$1 produces negative electricity4 ,electricity4 ,a batt]y has positive z well z negative electricity4 ,negative ,elem5t4 ,t plate 9 ! solution ( a batt]y cell :i* is n dis9tegrat$4 ,normal4 ,! usual1 or ord9>y4 ,! av]age4 ,9 a curr5t ! regul> =ce requir$ to d ! "w4 ,nor? ,pole1 ,! t]m appli$ to ! =ce locat$ ne> ,electric4 ! nor? pole ( ! globe1 to :i* a p]man5t magnet w po9t if all[$ to sw+ freely4 ,o4 ,abbreviation = ,ohm4 ,ohm4 ,! unit ( resi/ance4 ,equal to ! resi/ance ( a column ( m]cury "o squ>e millimet] 9 cross section1 & #ajf4bd c5timet]s 9 l5g?4 ,ohm's ,law4 ,x is express$ z foll[s3 #a4 ,! curr5t /r5g? is equal to ! electro-motive =ce divid$ by its resi/ance4 #b4 ,! electro-motive =ce is equal to ! curr5t /r5g? multipli$ by ! resi/ance4 #c4 ,! resi/ance is equal to ! electro-motive =ce divid$ by ! curr5t /r5g?4 ,ov]load4 ,9 a motor an excess ( me*anical "w :i* causes ! armature to turn too sl[ly & produces heat4 ,phase4 ,"o complete oscillation4 ,! special =m ( a wave at any in/ant1 or at any int]val ( "t4 ,plate1 ,cond5s]4 ,9 a /atic ma*9e x is usually a plate ( glass & revoluble4 ,plate1 ,negative4 ,! plate 9 a batt]y1 su* z c>bon1 copp] or plat9um1 :i* is n attack$ by ! solution4 ,plat+1 ,electro-4 ,! me?od ( coat+ "o metal ) ano!r by electrolysis4 ,pol>ity4 ,! peculi>ity1 9 a body1 ( arrang+ itself ) ref]5ce to magnetic influ5ce4 ,p>allel4 ,:5 a numb] ( cells are c\pl$ s t _! simil> poles are gr\p$ toge!r4 ,t is to say1 z ! c>bon plates1 = in/ance1 are connect$ ) "o t]m9al1 & all ! z9c plates ) ! o!r t]m9al4 ,pol>ization4 ,:5 ! cell is depriv$ ( its electro-motive =ce1 or any "p ( x1 pol>ization is ! result4 ,x is usually caus$ by coat+ ( ! plates4 ,porosity4 ,hav+ small int]/ices or holes4 ,positive ,curr5t4 ,"o :i* deflects a ne$le to ! left4 ,positive ,any curr5t fl[+ f ! active elem5t1 ,electricity4 su* z z9c1 9 a batt]y4 ,! negative electricity fl[s f ! c>bon to ! z9c4 ,pot5tial1 ,electric4 ,! p[] :i* p]=ms "w 9 a circuit4 ,pot5tial ,en]gy4 ,t =m ( =ce1 :i*1 :5 lib]at$1 does or p]=ms "w4 ,p[] ,unit4 ,! volt-amp]es or watt4 ,prim>y4 ,! induction coil 9 induction ma*9es1 or 9 a trans=m]4 ,pu% ,button4 ,a ?umb piece :i* s]ves z a swit* to close a circuit :ile be+ press$ inw>dly4 ,quantity4 ,su* arrangem5t ( electrical connections :i* give (f ! l>ge/ am\nt ( curr5t4 ,receiv]4 ,an in/rum5t 9 telephony & telegraphy :i* receives or takes 9 ! s\nd or impulses4 ,relay4 ,! device :i* op5s or closes a circuit s z to admit a new curr5t :i* is s5t to a m di/ant po9t4 ,repulsion1 ,t t5d5cy 9 bodies to repel ea* o!r :5 ,electric4 simil>ly *>g$4 ,resili5ce4 ,! spr++ back to its =m] condition or position4 ,electricity has resili5ce4 ,resi/ance4 ,! quality 9 all conductors to oppose ! passage ( a curr5t4 ,resi/ance ,coil4 ,a coil made up ( wire :i* prev5ts ! passage ( a curr5t to a great] or less degree4 ,resi/ance1 ,! c\nt] =ce 9 an electrolyte :i* seeks ,electrolytic4 to prev5t a decompos+ curr5t to pass ?r\gh x4 ,resi/ance3 ,int]nal1 ,! oppos+ =ce to ! movem5t ( a curr5t ,ext]nal4 :i* is 9 ! cell or g5]ator4 ,?is is call$ ! int]nal4 ,t opposite action outside ( ! cell or g5]ator is ! ext]nal4 ,resonator1 ,an op5-circuit$ conductor = electrically ,electric4 res\nd+ or giv+ back a vibration1 usually exhibit$ by means ( a sp>k4 ,rheo/at4 ,a device :i* has an adju/able resi/ance1 s arrang$ t :ile adju/+ ! same ! circuit w n be op54 ,safety ,fuse4 ,a piece ( fusible metal ( su* resi/ance t x breaks d[n at a c]ta9 curr5t /r5g?4 ,saturat$4 ,:5 a liquid has tak5 up a soluble mat]ial to ! fulle/ ext5t x is !n completely saturat$4 ,second>y4 ,"o ( ! two coils 9 a trans=m]1 or induction coil4 ,second>y ,plates4 ,! br[n or deep r$ plates 9 a /orage batt]y :5 *>g$4 ,self-excit$4 ,produc+ electricity by its own curr5t4 ,s]ies4 ,arrang$ 9 regul> ord]4 ,f "o to ! o!r directly4 ,if lamps1 = in/ance1 %\ld be arrang$ 9 circuit on a s+le wire1 !y w\ld be 9 s]ies4 ,s]ies1 ,multiple4 ,:5 lamps are gr\p$ 9 sets 9 p>allel1 & ^! sets are !n connect$ up 9 s]ies4 ,s]ies ,w9d+s4 ,a g5]ator or motor w\nd 9 su* a mann] t "o ( ! commutator bru% connections is jo9$ to ! field magnet w9d+1 & ! o!r end ( ! magnet w9d+ jo9$ to ! out] circuit4 ,%unt4 ,go+ ar\nd4 ,%unt ,w9d+4 ,a dynamo 9 :i* ! field w9d+ is p>allel ) ! w9d+ ( ! armature4 ,snap ,swit*4 ,a swit* s arrang$ t x w quickly make a break4 ,s\nd]4 ,! app>atus at "o end ( a l9e actuat$ by a key at ! o!r end ( ! l9e4 ,sp>k ,coil4 ,a coil1 to make a sp>k f a l[ electro-motive =ce4 ,sp>k1 ,electric4 ,! fla% caus$ by draw+ ap>t ! ends ( a conductor4 ,specific ,gravity4 ,! weight or d5sity ( a body4 ,/atic ,electricity4 ,g5]at$ by friction4 ,also lightn+4 ,any curr5t g5]at$ by a high electro-motive =ce4 ,/r5g? ( ,curr5t4 ,! quantity ( electricity 9 a circuit4 ,syn*ronize4 ,op]at+ toge!r2 act+ 9 unison4 ,t]m9al4 ,! end ( any electric circuit or ( a body or ma*9e :i* has a curr5t pass+ ?r\gh x4 ,!rmo/at1 ,electric4 ,an electric !rmomet]4 ,usually made ) a metal coil :i* exp&s ?r\gh ! action ( ! electricity pass+ ?r\gh x1 &1 9 exp&+1 x makes a contact & closes a circuit4 ,trans=m]4 ,! induction coil ) a high initial ,e4 ,m4 ,f4 *anges into a l[ electro-motive =ce4 ,unit4 ,a /&>d ( light1 heat1 electricity1 or ( o!r ph5om5a4 ,vacuum4 ,a space f :i* all matt] has be5 exhau/$4 ,vibrator4 ,me*anism = mak+ & break+ circuits 9 induction coils or o!r app>atus4 ,volt4 ,! unit ( electro-motive =ce4 ,voltage4 ,electro-motive =ce :i* is express$ 9 volts4 ,voltaic4 ,a t]m appli$ to electric curr5ts & devices4 ,volt-met]4 ,an app>atus = %[+ ! diff]5ce ( pot5tial1 or ,e4 ,m4 ,f4 9 ! t]m ( volts4 ,watt4 ,! unit ( electrical activity4 ,! product ( amp]es multipli$ by volts4 ,watt ,h\r4 ,"o watt ma9ta9$ ?r\gh "o h\r ( "t4 ,waves1 ,electric ,waves 9 ! e!r caus$ by electro-magnetic ,magnetic4 di/urbances4 ,x-rays4 ,! radiation ( invisible rays ( light1 :i* p5etrate or pass ?r\gh opaque sub/ances4 ,yoke1 or ,b>4 ,a s(t iron body across ! ends ( a horse%oe magnet1 to enable ! magnet to reta9 its magnetism an indef9ite "t4 ,z9c ,batt]y4 ,a batt]y :i* uses z9c = "o ( its elem5ts4 ,,index ,a ,accumulat$1 #ca4 ,accumulation1 #bi4 ,accumulator cell1 #hg4 ,accumulators1 #hb1 #hh1 #hi4 ,accumulators1 plates1 #hc4 ,acid1 #cd1 #cg1 #abe4 ,acid mak]1 #abe4 ,acid1 sulphuric1 #ca1 #hd4 ,acidulat$1 #ee4 ,acidulat$ wat]1 #cd4 ,ac\/ics1 #aaj4 ,act9ic rays1 #ahd1 #ahe4 ,act9ium1 #ahf4 ,active elem5t1 #hb4 ,adju/able rod1 #ajg4 ,adju/+ screw1 #gj1 #ga1 #gb1 #gc1 #ajf4 ,a]ial wire1 #ajh4 ,ag5ts1 #ac1 #cb4 ,al>ms1 burgl>1 #aa1 #gf1 #hj4 ,alkali1 #abe4 ,alkal9e1 #cg4 ,alt]nate1 #abg4 ,alt]nat+1 #ch1 #adi1 #aej1 #aec1 #aed1 #aee1 #aef4 ,alt]nat+ curr5t1 #ade4 ,alt]nat+ p]iods1 #adi4 ,alt]nations1 #adg4 ,alum9um1 #abh1 #abi1 #ace1 #acg4 ,alum9um hydrate1 #abi4 ,amb]1 #e1 #aga4 ,ammet]1 #g1 #hh4 ,amp]age1 #ch1 #fa1 #fb1 #acb1 #aei1 #afj1 #afh4 ,amp]e1 #g1 #cg1 #fj1 #fc1 #aci1 #adj1 #afg4 ,amplitude1 #aaa4 ,annunciator1 #fe1 #gd1 #gf1 #gi1 #hj1 #ha4 ,annunciator bells1 #aa4 ,anode1 #ce1 #acc1 #acd4 ,ant5n1 #ajh4 ,antimony #acg1 #adc4 ,anvil1 #ac1 #ad4 ,app>atus1 #aa1 #eg1 #ajf1 #aci1 #ade4 ,arc1 #afc1 #ahb4 ,arc light+1 #ch1 #afe4 ,arc sy/em1 #aff4 ,armature1 #ah1 #be1 #ch1 #dj1 #db1 #dc1 #de1 #df1 #dg1 #dh1 #ec1 #ee1 #gj1 #gb1 #gc1 #gd1 #ij1 #ic1 #aab1 #aea1 #aeb1 #aee1 #afc1 #agf1 #agg1 #agh1 #agi1 #ahj4 ,armature bru%1 #dh4 ,armature po/1 #ga4 ,armature1 v]tical1 #ge4 ,armature w9d+1 #db1 #dc1 #aef4 ,asbe/os1 #adj4 ,a/atic galvanomet]1 #ajh4 ,atmosph]e1 #ahd4 ,attract1 #cj4 ,attract$1 #gb4 ,attraction1 #ba1 #be4 ,attractive1 #agh4 ,automatic1 #abj4 ,auxili>y1 #dd4 ,awls1 #ad4 ,b ,bact]ia1 #abf1 #ahg4 ,b>1 cross1 #ff4 ,b>1 horizontal1 #df4 ,b>1 p>allel swit*1 #fg4 ,b>1 swit*1 #fe1 #fh4 ,base block1 #ff4 ,batt]ies1 #aa1 #ic1 #abb4 ,batt]y1 #bi1 #cj1 #cb1 #ce1 #cf1 #df1 #dg1 #hj1 #ha1 #hb1 #hc1 #he1 #hf1 #hh1 #ib1 #id1 #ie1 #ajg1 #ajh1 #aaf1 #aag1 #aah1 #aba1 #acd1 #adb4 ,batt]y *>g+1 #hb4 ,be>+s1 #de1 #df4 ,bells1 #fe1 #gc1 #gf1 #abb4 ,bells1 electric1 #gj4 ,b5*1 #ac1 #ae1 #ag4 ,b9d+ po/1 #eb1 #gj1 #ga1 #gb1 #ajc1 #ajg1 #ajh1 #aba4 ,b9d+ screw1 #fe1 #ff4 ,bismu?1 #ah1 #adc4 ,bit1 #ac4 ,blue vitriol1 #eg4 ,brass plate1 #gg1 #gh4 ,braz+1 #ag1 #fe4 ,bridge1 #eb4 ,bru% hold]1 #df4 ,bru%es1 #dh1 #aej1 #aea1 #aec1 #afg4 ,burgl>1 #aa4 ,burgl> al>m1 #gf1 #hj4 ,buttons1 contact1 #hj4 ,buttons1 pu%1 #fe1 #fh1 #fi1 #gj1 #gf1 #gi4 ,c ,calorimet]1 #ef4 ,canc]\s1 #ahg4 ,c&le p[]1 #hi1 #aci4 ,cap1 removable1 #gc4 ,cap screws1 #db4 ,c>bon1 #ce1 #aai1 #aba1 #afb1 #afc1 #afi4 ,c>bon block1 #abj4 ,c>bon p5cil1 #aai4 ,ca?ode1 #ce1 #cf1 #acc1 #acd4 ,cell1 #bi1 #cc4 ,cell1 accumulator1 #hg4 ,cell1 *>g+1 #hg4 ,*annel1 #dc4 ,*annel1 concave1 #dj4 ,*>g$1 #abj4 ,*>g$ batt]y1 #hb4 ,*>g+ circuit1 #hb1 #hi4 ,*>g+ s\rce1 #hc4 ,*>g$ wire1 #adg4 ,*emical1 #eg4 ,*isels1 #ac4 ,*loride ( lime1 #hd4 ,*ok$1 #aeg4 ,*ok+ coils1 #ade1 #adf1 #aef1 #aeh4 ,circuit1 #cc1 #fi1 #gc1 #gf1 #gh1 #hj1 #ha1 #ij1 #ib1 #ic1 #aji1 #aac1 #aaf1 #aba1 #abb1 #aca1 #acd1 #adc1 #aef4 ,circuit1 prim>y1 #ii4 ,circuit1 second>y1 #ii4 ,circuit+1 #ha1 #aee4 ,circuit+ sy/em1 #gi4 ,clapp] arm1 #gj4 ,clos$ r+s1 #bf4 ,coh]]1 #aje1 #ajh1 #aji4 ,coh]+1 #ajf4 ,coils1 #ah1 #bf1 #eb1 #ee1 #gd1 #afj4 ,coils1 *ok+1 #ade1 #adf1 #aef1 #aeh4 ,coils1 induction1 #ii1 #ajb4 ,coils1 prim>y1 #aji4 ,coils1 second>y1 #ajb1 #aji4 ,co9cide1 #db4 ,cold1 #ad4 ,collect+ surfaces1 #cj4 ,collector1 #ca4 ,column1 #fa4 ,combu/ion1 #afi4 ,commutator1 #dd1 #df1 #aea1 #aeb4 ,commutator bru%es1 #df4 ,commutator plates1 #de4 ,compass1 #bb1 #bd1 #agb4 ,composition1 #hc1 #abd4 ,comp\nd w\nd1 #dg4 ,concave *annel1 #dj4 ,cond5s]1 #ih1 #ajj1 #aja1 #ajb1 #ajh4 ,conduct1 #f1 #ajh4 ,conduction1 #ace1 #acf1 #ach1 #aff1 #agj4 ,conduction curr5t1 #bg4 ,conductor1 #ba1 #ca1 #cc1 #fc1 #ih1 #aaf1 #afa1 #afb4 ,conduit1 #gb4 ,conically =m$1 #abf4 ,conjunction1 #adc4 ,connect+ wire1 #eh4 ,connection1 #gb1 #gf4 ,con/ruction1 magnet1 #ci4 ,consumption1 #ahj4 ,contact1 #abb1 #abc1 #aeb1 #afb4 ,contact f+]1 #aej4 ,contact plate1 #fg1 #fh1 #gi4 ,contact screws1 #ic4 ,contact surface1 #ff4 ,cont9u\s1 #ade4 ,conv]t]1 #agf4 ,conv]t+1 #adb1 #ade1 #adf4 ,copp]1 #ah1 #cd1 #cf1 #fe1 #ff1 #acb1 #acc1 #acd1 #ace1 #acf1 #acg1 #adb1 #adc4 ,copp] cyanide1 #acc4 ,copp] plate1 #cc1 #ce1 #eh1 #fg4 ,copp] sulphate1 #eg4 ,copp] voltamet]1 #ee1 #eg4 ,core1 #bg1 #bh1 #cf1 #ci1 #dj1 #aae4 ,core1 magnet1 #ge1 #ic4 ,c\nt]1 clock-wise1 #ea4 ,c\pl$1 #cf4 ,crank1 #cj4 ,crookes' tube1 #ahd4 ,cross b>1 #eb1 #ff4 ,cr[n ( cups1 #cb4 ,cry/al1 #he4 ,curr5t1 #f1 #g1 #ac1 #ah1 #bf1 #bg1 #bh1 #ce1 #cf1 #cg1 #ch1 #dg1 #ej1 #ea1 #eb1 #ee1 #ef1 #eg1 #eh1 #ei1 #fb1 #fc1 #gj1 #gb1 #gc1 #ij1 #ie1 #ih1 #aje1 #ajh1 #aaf1 #acc1 #acd1 #ace1 #acf1 #ach1 #aci1 #adj1 #ada1 #adb1 #adc1 #adg1 #adh1 #adi1 #aej1 #aeb1 #aec1 #aeg1 #afj1 #afa1 #afc1 #afe1 #aff1 #agj4 ,curr5t1 alt]nat+1 #aej4 ,curr5t *ang+1 #hb4 ,curr5t conduction1 #bg4 ,curr5t1 cont9u\s1 #afd4 ,curr5t1 direct1 #ade1 #aej4 ,curr5t direction1 #ej4 ,curr5t1 ext]ior1 #ej1 #aej4 ,curr5t1 rev]s+1 #adh4 ,curr5t /r5g?1 #g1 #eg4 ,curr5t te/+1 #adc4 ,cut-out1 #abj4 ,cutt]1 #ad4 ,cutt+1 l9es ( =ce1 #ch4 ,cyl9d]1 #dd4 ,cyl9drical1 #dc4 ,d ,da%1 #ie1 #ig4 ,decoh]]1 #ajf1 #ajh4 ,decompos$1 #eg1 #abh4 ,decomposes1 #ee4 ,decompos+1 #abc4 ,decomposition1 #ab1 #ce1 #hb4 ,deflect$1 #ed4 ,degree1 #ace1 #afb4 ,demagnetiz$1 #bd1 #gb4 ,deposit$1 #eh1 #acc4 ,depression1 #ae1 #adj4 ,detect+ curr5t1 #di4 ,detector1 #di1 #eb1 #ed1 #aje4 ,devices1 measur+1 #bg4 ,diagrams1 #df1 #dh1 #gi1 #hi4 ,diagrammatically1 #ha4 ,diamagnetic1 #ai4 ,diametrically1 #aad4 ,diaphragm1 #aab1 #aac1 #aaf1 #abj1 #abb4 ,diamonds1 #ahf4 ,dilut$1 #hf4 ,direct curr5t1 #ch1 #adj4 ,direction ( curr5t1 #ej4 ,direction ( fl[1 #ih4 ,dis*>ge1 #agb4 ,dis9tegrate1 #acb4 ,disk1 #dc4 ,dissimil>1 #cg4 ,di/urbance1 #agf4 ,divid]s1 #ad4 ,divisibility1 #afh4 ,dot1 #if1 #ig4 ,dot & da%1 #if4 ,d\ble click1 #ie4 ,d\ble l9e1 #fe4 ,d\ble-pole swit*1 #fe4 ,d\ble-?r[ swit*1 #aag4 ,draw+1 #bj4 ,drill1 rat*et1 #ac4 ,drops1 #ha4 ,ductile1 #ahf4 ,duplex wire1 #aae4 ,dynamo1 #g1 #bg1 #ch1 #db1 #df1 #dh1 #fb1 #hb1 #hc1 #hg1 #hi1 #acb1 #ada1 #adb1 #ade1 #aej1 #aee1 #afa1 #afe1 #afg1 #age1 #agf1 #ahj1 #ahg4 ,dynamo fields1 #dj1 #da4 ,e ,e>?1 #bb4 ,ela/icity1 #ajj1 #adb4 ,electric1 #f1 #ca1 #di1 #ej1 #gf1 #gh1 #ha1 #aca1 #adb1 #aeh1 #afb1 #agc1 #agf4 ,electric arc1 #fc1 #afc4 ,electric bell1 #ai1 #fi1 #gj1 #ga1 #gb1 #ajf1 #aag4 ,electric bulbs1 #afg4 ,electric circuit1 #aah4 ,electric fan1 #ee4 ,electric field1 #gf4 ,electric h& purifi]1 #abi4 ,electric heat+1 #ace1 #acg1 #afa4 ,electric iron1 #acj1 #ada4 ,electric lamp socket1 #aci4 ,electric light1 #ef1 #ff4 ,electric light+1 #afa4 ,electric p[]1 #aac4 ,electric weld+1 #ahc4 ,electrical1 #h1 #aa1 #fe1 #if1 #ih1 #ajd1 #ada1 #aei1 #ahj1 #ahd1 #ahg4 ,electrical impulses1 #aje1 #adg1 #adh4 ,electrical manife/ations1 #age4 ,electrically1 #cb1 #gj4 ,electricity1 #e1 #f1 #g1 #h1 #i1 #ab1 #ac1 #ah1 #ba1 #bf1 #bg1 #bh1 #bi1 #ch1 #di1 #ed1 #fj1 #fa1 #fb1 #hb1 #ig1 #ih1 #ajj1 #ajd1 #aaj1 #aab1 #aaf1 #abc1 #abd1 #acc1 #acd1 #acf1 #ach1 #ade1 #adf1 #adg1 #aed1 #aef1 #afj1 #aff1 #agj1 #aga1 #agb1 #age1 #ahb1 #ahg4 ,electricity measur+1 #di4 ,electricity1 !rmo-1 #adb4 ,electrifi$1 #cg1 #ahf4 ,electro-*emical1 #ee4 ,electrode1 #ce1 #abd1 #abg1 #abh1 #afa1 #afb1 #afc1 #afd1 #afe1 #ahd4 ,electrolysis1 #g1 #abc1 #abf1 #acb4 ,electrolyte1 #cc1 #ce1 #cf1 #eg1 #hf1 #hh1 #abc1 #acb1 #adb4 ,electrolytic1 #ee1 #abc1 #abe4 ,electro-magnet1 #ei1 #gh4 ,electro-magnetic1 #g1 #bd1 #be1 #bi1 #cg1 #ee1 #ib1 #ic1 #id4 ,electro-magnetic =ce1 #g4 ,electro-magnetic rotation1 #g4 ,electro-magnetic swit*1 #aaf4 ,electro-met]1 #g4 ,electro-motive =ce1 #cg1 #fc1 #ii4 ,electroplate1 #ab1 #ch1 #dh1 #abc1 #acb1 #acd4 ,electro-positive-negative1 #adb1 #adc4 ,elem5ts1 #cf1 #hc4 ,eng9e en]gy1 #agj1 #ahj4 ,equidi/ant1 #abg4 ,e!r1 #ajd4 ,example1 #fa4 ,excit$1 #dg4 ,ext5sion plate1 #ajc4 ,ext]ior1 #c4 ,ext]ior magnetic1 #bg4 ,ext]nal1 #cg4 ,ext]nal circuit1 #aec4 ,ext]nal curr5t1 #ej4 ,ext]nal resi/ance1 #cg4 ,f ,factor1 #fa4 ,f]r\s oxide1 #abe4 ,field1 #df1 #dg4 ,field1 dynamo1 #dj1 #da4 ,field magnet cores1 #aee4 ,field1 magnetic1 #ch4 ,field ( =ce1 #cc4 ,field wire1 #dh4 ,filam5t1 #afh1 #afi1 #agj4 ,filt]1 #abh4 ,flat iron1 #adj4 ,floccul5t1 #abh4 ,=ce1 #ej4 ,=mulat$1 #ai4 ,friction1 #cb4 ,frictional1 #f1 #g1 #bi4 ,fuse1 #afi4 ,g ,galvani1 #g4 ,galvanic1 #g1 #bc1 #cj4 ,galvanomet]1 #g1 #di1 #ajh1 #adc4 ,galvanoscope1 #ee1 #eh1 #ei4 ,gase\s1 #abh4 ,gasol9e1 #ii4 ,gas /ove1 #ag4 ,gelat9e1 #abh4 ,g5]ate1 #bi1 #ch1 #acd1 #acf1 #ade4 ,g5]at$1 #ee4 ,g5]at+1 #cb1 #acd4 ,g5]ation1 #agj4 ,g5]ator1 #cb1 #abe1 #adg4 ,g]man silv]1 #acf1 #acg4 ,g]micide1 #ahg4 ,gimlets1 #ag4 ,glass1 #cj1 #hf1 #abf1 #ahf4 ,gold1 #ace4 ,grid1 #hd4 ,gr\nd circuit1 #aba4 ,gunp[d]1 #f4 ,h ,hack-saw1 #ad4 ,hamm]1 #ac4 ,he>t-%ap$ swit*1 #gg4 ,heat]1 #acf4 ,heat+1 #ac1 #ch4 ,h]tzian rays1 #agj4 ,h]tzian wave1 #ahd4 ,high t5sion1 #ch1 #ajb1 #ahd4 ,high t5sion app>atus1 #ih4 ,high t5sion coils1 #ajc4 ,high voltage1 #aeh4 ,horizontal b>1 #df4 ,horse%oe magnet1 #bb1 #bd1 #age4 ,hydrate ( alum9um1 #abi4 ,hydrog51 #ce1 #abc1 #abe1 #abh4 ,i ,ignit+1 #ii4 ,illum9ation1 #afb1 #afc1 #afe1 #afg1 #agj4 ,imm]s$1 #acc4 ,impulses1 #fj1 #fb1 #if1 #ajd1 #aji1 #aeb1 #agi4 ,inc&esc5t1 #aff1 #afh4 ,induc$1 #bh4 ,inductance1 #adi1 #aej4 ,induction1 #bg1 #cg1 #ih1 #adg4 ,induction coils1 #ii1 #ajb1 #ajf4 ,influ5ces1 #agh4 ,initial *>ge1 #hh4 ,insulat$1 #bg1 #bh1 #dj1 #dc1 #eb1 #ee1 #gc1 #aae1 #aea1 #ahj4 ,insulat+1 #ff1 #fi1 #abj1 #adj1 #afd4 ,insulat+ mat]ial1 #aad4 ,insulation1 #dj1 #aaf4 ,in/rum5ts1 #di1 #id1 #aab1 #aah1 #abj4 ,in/rum5ts1 measur+1 #h4 ,int5sity1 #ee1 #fj1 #ajd1 #aed4 ,int]ior1 magnetic1 #bc4 ,int]nal resi/ance1 #cg4 ,int]ruption1 #ajb1 #ajc4 ,in/allation1 #afh4 ,ionize1 #ahf4 ,iron1 #ai1 #acb1 #acc1 #acf1 #adb1 #aga4 ,isolat$1 #ahf4 ,j ,j>1 #bi1 #ca1 #cb4 ,j\rnal1 #df4 ,j\rnal block1 #af1 #adf4 ,jump sp>k1 #ii4 ,k ,key1 #ij1 #ia1 #ie4 ,key1 s5d+1 #ij4 ,knob1 #cb4 ,knob1 t]m9al1 #ca4 ,l ,laboratory1 #i4 ,lead1 #ca1 #acf4 ,lead1 precipitat$1 #hc1 #he4 ,lead1 r$1 #hc1 #hd4 ,lev] swit*+1 #fg4 ,light1 #ajd4 ,light me?od1 #ef4 ,light+1 #i1 #ch4 ,light+ circuit1 #dh4 ,light+ sy/em1 #hb4 ,lightn+1 #f1 #aga1 #agb1 #agc4 ,lightn+ rod1 #agc4 ,lime1 *loride (1 #hd4 ,l9e ( =ce1 #adf4 ,l9e wire1 #abb4 ,l9e1 magnetic1 #bb1 #bc4 ,liquid1 #cb4 ,li?>ge1 #hc4 ,load/one1 #ag4 ,locomotives1 #afe4 ,l[ t5sion1 #ch1 #ih1 #ajb1 #agi4 ,m ,magnet b>1 #bj4 ,magnet core1 #af1 #ge1 #ic4 ,magnet1 electro1 #ei1 #gh4 ,magnet1 horse%oe1 #bb1 #be1 #age4 ,magnet l9es1 #bb1 #bc4 ,magnet1 p]man5t1 #be1 #ch1 #df1 #ej1 #agb4 ,magnet1 rev]s$1 #bj4 ,magnet1 /eel1 #ec4 ,magnet1 sw++1 #ec4 ,magnetic1 #g1 #ai1 #bj1 #ba1 #bb1 #be1 #aac1 #agh4 ,magnetic con/ruction1 #ci4 ,magnetic ext]ior1 #bg4 ,magnetic field1 #bb1 #bd1 #bg1 #ch1 #ej1 #aab1 #adf1 #adh1 #aee4 ,magnetic int]ior1 #bc4 ,magnetic pull1 #ei4 ,magnetic radiator1 #cg4 ,magnetism1 #ai1 #ed1 #ajd1 #aaj1 #aei1 #aga4 ,magnetiz$1 #ah1 #be1 #bg1 #ej4 ,magnetiz$ wire1 #adf4 ,magnets1 #ac1 #ad1 #ah1 #ai1 #bj1 #ba1 #bb1 #bc1 #bd1 #be1 #ci1 #ea1 #ec1 #ed1 #gj1 #ga1 #gc1 #ge1 #ha1 #ij1 #ic1 #aab1 #aac1 #aae1 #adg1 #aej1 #afc1 #agf1 #agg1 #agh4 ,ma9 conductor1 #ca4 ,m&rel1 #ae1 #af4 ,manganese1 #ai4 ,manife/ations1 #ai4 ,m>9]1 #agb4 ,mat]ial1 non-conduct+1 #ij4 ,maximum1 #aed4 ,measure1 #ee1 #ef1 #fj1 #fb4 ,measurem5t1 #fb4 ,measur+ devices1 #bg4 ,measur+ in/rum5ts1 #h4 ,me*anism1 #dg1 #ahj4 ,m$ical batt]ies1 #ii4 ,m]cury1 #fc1 #afi4 ,metal base1 #gc4 ,mica1 #ahf4 ,microphone1 #aah1 #aai1 #abj4 ,millimet]1 #fc4 ,m9us1 #cd4 ,m9us sign1 #ba4 ,morse code1 #gf4 ,motor1 #g1 #ba1 #bg1 #df1 #dg1 #fb1 #hb1 #ii1 #aej1 #agf1 #ahj4 ,m\?piece1 #aae4 ,m\?piece rays1 #ahh4 ,mov+ field1 #aag4 ,multiple1 #afh4 ,musical scale1 #aaa4 ,n ,negative1 #ba1 #ce1 #cf1 #fh1 #hc1 #hf1 #hg1 #id1 #abe1 #aea1 #aeb1 #aed1 #afe1 #agg1 #agh1 #agi4 ,neutral1 #abe4 ,neutral plate1 #hd4 ,nickel1 #acf4 ,nickel plat+1 #acb4 ,nitrate ( silv]1 #fb4 ,nitrog51 #abf4 ,non-conduct+ mat]ial1 #ij4 ,non-conductor1 #afd4 ,non-magnetic1 #ai4 ,nor? pole1 #bj1 #ba1 #bb1 #bc1 #be1 #ej1 #ed1 #aef4 ,numb] plate1 #ge4 ,n-ray1 #ahh4 ,o ,ohms1 #fj1 #fc4 ,ohms1 int]national1 #fc4 ,ohms law1 #g4 ,op]ator1 #ie1 #aah4 ,oscillat+1 #ii1 #aje4 ,osmium1 #afi4 ,oxides1 #abe4 ,oxidiz+1 #ahc4 ,oxyg51 #ce1 #abc1 #abe1 #abf1 #abh1 #abi1 #afi4 ,p ,pack+ r+1 #abd4 ,p>aff9e1 #ef1 #ajj1 #aja1 #ajb4 ,p>aff9e wax1 #hf4 ,p>allel1 #hg1 #hh1 #hi4 ,p>allel swit* b>1 #fg4 ,p>allel wires1 #bh1 #di4 ,p>tition1 #abd4 ,peon1 #ac4 ,p]colate1 #abh4 ,p]iodicity1 #aei4 ,p]iods ( alt]nations1 #adi4 ,p]man5t1 #ah1 #ai1 #ej4 ,p]man5t magnet1 #be1 #ch1 #df1 #ej1 #agb4 ,phase1 #ai4 ,ph5om5on1 #bg1 #fe4 ,photograph1 #ahf4 ,physical1 #ba4 ,pile1 voltaic1 #cc4 ,pipe1 #fa4 ,pit*bl5de1 #ahf4 ,pivot p91 #ec4 ,pivotal1 #bb4 ,plane1 #ac4 ,plate1 #eg1 #ic4 ,plate1 contact1 #fg1 #fh1 #gi4 ,plate1 copp]1 #cc1 #ce1 #eh1 #fg4 ,plate1 negative1 #hd4 ,plate1 numb]1 #ge4 ,plate1 positive1 #hd1 #hh4 ,plate1 z9c1 #cc4 ,plat9um1 #ac1 #eg1 #acg4 ,pli]s1 #ad4 ,plus sign1 #ba1 #bd4 ,po9t]1 #ec4 ,pol>ity1 #aed1 #agg1 #agh1 #agi4 ,pol>ization1 #ce4 ,pole1 nor?1 #bj1 #ba1 #bb1 #bc1 #be1 #ej1 #ed1 #aef4 ,pole piece1 #dj1 #db4 ,pole1 s\?1 #bj1 #ba1 #bb1 #be1 #ej1 #ed1 #aef4 ,poles1 #agg1 #agi4 ,polonium1 #ahf4 ,porcela91 #hf4 ,por\s1 #he4 ,positive1 #d1 #ba1 #be1 #cf1 #dj1 #fh1 #hc1 #hf1 #hg1 #id1 #abc1 #abe1 #aea1 #aeb1 #aec1 #aee1 #afe4 ,po/1 b9d+1 #eb1 #ga4 ,pot5tiality1 #aje1 #aji4 ,p[]1 #ch1 #ahf4 ,p[]1 c&le1 #hi1 #aci4 ,precipitate ( lead1 #hc1 #he4 ,precision1 #g4 ,pressure1 #hg4 ,prim>y1 #ce1 #fb1 #ih1 #acd1 #adb1 #aei1 #ahd4 ,prim>y batt]y1 #g1 #ii4 ,prim>y circuit1 #ii4 ,prim>y coil1 #ajf1 #aji4 ,prime conductor1 #f4 ,project$1 #ahe4 ,propagat$1 #aje1 #ahe4 ,prop]ties1 #ee4 ,purification1 #abc1 #abh4 ,purifi]1 #abf1 #aca4 ,pu% button1 #fe1 #fh1 #fi1 #gj1 #gf1 #gi4 ,q ,quantity1 #ee1 #fj1 #fa1 #ach4 ,qu>tz1 #ahf4 ,r ,radio-activity1 #ahf4 ,radium1 #ahd1 #ahe1 #ahg1 #ahh4 ,rat*et drill1 #ac4 ,reaction1 #adh4 ,receiv]1 #ab1 #ij1 #ig1 #aba1 #abb4 ,receiv+ /ation1 #aji4 ,rectangul>1 #fi4 ,rectifi]s1 #adf4 ,r$ lead1 #hc1 #hd4 ,reel1 #ac4 ,reflect$1 #ahe4 ,refraction1 #ahe4 ,refractory1 #ahb4 ,regi/]1 #eg4 ,removable1 #ed4 ,removable cap1 #gc4 ,repel1 #bj4 ,repulsion1 #ba1 #abh4 ,res]voir1 #fa1 #fb4 ,resili5cy1 #ii4 ,resi/ance1 #g1 #cf1 #cg1 #fj1 #fc1 #ii1 #ace1 #acf1 #acg1 #ach1 #adj1 #ada1 #aef1 #aeg1 #afc1 #aff1 #afh4 ,resi/ance bridge1 #g4 ,resi/ance1 ext]nal1 #cg4 ,resi/ance1 int]nal1 #cg4 ,rheo/at1 #g4 ,rev]s$1 #bj1 #ej1 #aec4 ,rev]sible1 #afc4 ,rev]s+1 #agf4 ,rev]s+ swit*1 #fg4 ,revolubly1 #df4 ,revolve1 #agi4 ,revolv+1 #agg4 ,ro5tg5 rays1 #ahd4 ,ro5tg5 tube1 #ahg4 ,rotation1 #adi4 ,rubb]1 #dj1 #df1 #gg1 #aae1 #abf1 #acj1 #ach4 ,s ,sad-irons1 #ac4 ,sal9e1 #acc4 ,sanitation1 #ab4 ,saturat$1 #he4 ,screw1 #ae4 ,screw1 b9d+1 #fe1 #ff4 ,screw-driv]1 #ad4 ,screw1 set1 #gb4 ,seal+ wax1 #ec4 ,second>y1 #fb1 #ih1 #aje1 #aeh1 #aei1 #afj4 ,second>y circuit1 #ii4 ,second>y coil1 #ajg1 #ajh4 ,self-induction1 #adi1 #aef4 ,s5d]1 #ij1 #ig4 ,s5d+ app>atus1 #ajf4 ,s5d+ key1 #ij4 ,sep>ately excit$1 #df4 ,s]ies-w\nd1 #dg4 ,sev]$ magnet1 #bj4 ,sewage1 #ab4 ,%aft1 #cj4 ,%e>s1 #ad1 #ag4 ,%ellac1 #dj4 ,%unt-w\nd1 #dg4 ,signal1 #aah4 ,silv]1 #ai1 #fc1 #abe4 ,silv] nitrate1 #fb4 ,socket1 #ed1 #aci4 ,sold]+1 #ad4 ,sold]+ iron1 #ag4 ,solution1 #ee1 #eg1 #fb1 #fc1 #hd1 #hf1 #acc1 #acd1 #adb4 ,s\nd]1 #ij1 #ib1 #ie1 #if4 ,s\nd+ bo>d1 #aai4 ,s\rce1 *>g+1 #hc4 ,s\? pole1 #bj1 #ba1 #bb1 #be1 #ej1 #ed1 #aef4 ,sp>k gap1 #ajb1 #ajf4 ,sp>k jump1 #ii4 ,spr+ f+]1 #fi4 ,squ>e1 #ad1 #ag4 ,/&>d1 #fb1 #fc4 ,/ation1 #id1 #ie1 #aag1 #abb4 ,/eel1 #ah1 #ai4 ,/eel magnet1 #ec4 ,/]iliz$1 #ab4 ,/irrup1 #ge4 ,/ock bit1 #ac4 ,/ock contact1 #aba4 ,/orage1 #hb4 ,/orage batt]y1 #ajg4 ,/or+1 #hb4 ,sub/ances1 #ace4 ,sulphate1 #ee1 #abh1 #acc4 ,sulphur1 #ai4 ,sulphuric acid1 #ca1 #hd4 ,sulphuric acid voltamet]1 #ee1 #eg4 ,sup]/ition1 #aga1 #agc4 ,surg+1 #aec1 #aed4 ,sw++ magnet1 #ec4 ,sw++ swit* blade1 #fg4 ,swit* blades1 #ff4 ,swit*es1 #fe1 #ff1 #gj1 #gg1 #gh1 #ij1 #aag4 ,swit*es1 b>1 #fe1 #fh1 #ij1 #ia4 ,swit*es1 b>1 p>allel1 #fg4 ,swit*es1 he>t-%ap$1 #gh4 ,swit*es1 piece1 #gg4 ,swit*es1 rev]s+1 #fg4 ,swit*es1 slid+1 #fg1 #hj4 ,swit*es1 t]m9al1 #h4 ,swit*es1 two-pole1 #fe4 ,sy/em1 circuit+1 #gi4 ,t ,tail-piece1 #af4 ,tantalum1 #afi4 ,telegraph1 #aa1 #ij1 #if4 ,telegraph key1 #ajf4 ,telegraph s\nd]1 #ajh1 #aji4 ,telegraph+1 #id4 ,telephone1 #ab1 #aaj1 #aac1 #aag1 #aah1 #aai1 #abj4 ,telephone circuit1 #aah4 ,telephone connections1 #aaf4 ,telephone hook1 #abb4 ,temp]ature1 #ef1 #hh1 #acd1 #afa1 #agj4 ,t5sion1 high1 #ch1 #ajb1 #ahd4 ,t5sion1 l[1 #ch1 #ih1 #ajb1 #agi4 ,t]m9al1 #ca1 #cd1 #ce1 #dj1 #dh1 #hb1 #hf1 #ic1 #ie1 #ajg1 #aaf1 #aba1 #abb1 #aea1 #aeb1 #aec1 #aed1 #aef4 ,t]m9al knob1 #ca4 ,t]m9al1 second>y1 #ajb4 ,t]m9al swit*1 #ha4 ,!oretical1 #afj4 ,!rapeutics1 #ahg4 ,!rmo-electric c\ples1 #adf4 ,!rmo-electricity1 #ace4 ,!rmomet]1 #ef4 ,?orium1 #afi1 #ahf4 ,?und]bolt1 #aga1 #agc4 ,t91 #acf4 ,t9foil1 #ca1 #aja4 ,tools1 #aa1 #ac1 #ag4 ,tor*1 braz+1 #ag4 ,trans=m]1 #ade1 #adf1 #aeh1 #aei1 #ahj1 #ahb4 ,trans=m]1 /ep-d[n1 #ahb4 ,transmission1 #ch1 #ahg4 ,transmit1 #fc1 #ie1 #aeg4 ,transmitt]1 #ab1 #abj1 #aba1 #abb1 #abc4 ,transv]se1 #af1 #eb4 ,transv]sely1 #dc4 ,trigg]1 #ge4 ,tripod1 #ca4 ,tubul>1 #dd1 #de4 ,two-pole swit*1 #fe4 ,u ,ultra-violet1 #ahe4 ,uranium1 #ahf4 ,v ,vacuum1 #ahd4 ,vapor lamps1 #afi4 ,velocity1 #fj1 #gc4 ,v]tical armature1 #ge4 ,vibration1 #aaj1 #aaa1 #aac4 ,vibratory1 #aaj4 ,vise1 #ac4 ,voltage1 #cg1 #ch1 #fj1 #fa1 #fb1 #fc1 #hg1 #hh1 #ii1 #adg1 #aed1 #afe1 #ahj1 #ahb4 ,voltage1 high1 #aeh4 ,voltaic1 #bi1 #cb4 ,voltaic pile1 #cc4 ,voltamet]1 #g1 #eh1 #hh4 ,voltamet]1 sulphuric1 acid1 #ee1 #eg4 ,volts1 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