,transcrib]'s ,notes ,text pr9t$ 9 italics has be5 transcrib$ betwe5 und]scores1 bold face text has be5 transcrib$ betwe5 equal signs4 ,small capitals h be5 replac$ ) all capitals4 ,s+le lett]s 9 squ>e brackets1 su* z ,t & ,v1 repres5t %apes r ?an lett]s4 ,m ,transcrib]'s ,notes may be f\nd at ! end ( ?is text4 ,h>p]'s ,practical ,books = ,boys ,a ,,s]ies ,,( ,,new ,,h&y-,,books ,,= ,,am]ican ,,boys ,ea* ,cr[n #hvo1 ) _m ,illu/rations4 ,i ,,h>p]',s ,,outdoor ,,book ,,= ,,boys ,by ,joseph ,h4 ,adams4 ,) ,additional ,contributions by ,kirk ,munroe1 ,tappan ,adney1 ,capt4 ,h[>d ,patt]son1 ,l4 ,m4 ,yale1 & o!rs4 ,clo?1 #a4ge4 ,,ii ,,h>p]',s ,,electricity ,,book ,,= ,,boys ,writt5 & ,illu/rat$ by ,joseph ,h4 ,adams4 ,) a ,diction>y ( ,electrical ,t]ms4 ,clo?1 #a4ge4 ,,9 ,,press ,,iii ,,h>p]',s ,,h[ ,,to ,,und]/& ,,electrical ,,"w ,a ,simple ,explanation ( ,electric ,light1 ,heat1 ,p[]1 & ,traction 9 ,daily ,life4 ,by ,joseph ,b4 ,bak]1 ,te*nical ,editor1 ,u4 ,s4 ,geological ,survey1 =m]ly ( ! ,g5]al ,electric ,company4 ,,iv ,,h>p]',s ,,indoor ,,book ,,= ,,boys ,by ,joseph ,h4 ,adams & o!rs4 ,clo?1 #a4ge4 ,v ,,h>p]',s ,,ma*9]y ,,book ,,= ,,boys ,! ,boy's ,own ,book ( ,eng9es & ,ma*9]y4 ,clo?1 #a4ge4 ,,h>p] ,,bro!rs1 ,,publi%]s1 ,,new ,,york ,illu/ration3 ,copyright1 #aijg1 by ,joseph ,h4 ,adams1 ,n4 ,y4 ,,?omas ,a4 ,,edison ,,dictat+ ,,to ,,8 ,,graphophone ,,h>p]',s ,,electricity ,,book ,,= ,,boys ,,writt5 ,,& ,,illu/rat$ ,,by ,,joseph ,h4 ,,adams ,,au?or ,,( 8,,h>p]',s ,,outdoor ,,book ,,= ,,boys0 ,,) ,,an ,,explanation ,,( ,,electric ,,light1 ,,heat ,,p[]1 ,,& ,,traction ,,by ,,joseph ,b4 ,,bak] ,,te*nical ,,editor1 ,u4 ,s4 ,,geological ,,survey ,,& ,a ,,diction>y ,,( ,,electrical ,,t]ms ,illu/ration ,,h>p] ,,bro!rs ,,publi%]s ,,new ,,york ,,& ,,london ,,mcmvii ,copyright1 #aijg1 by ,,h>p] ,,bro!rs4 ,all rights res]v$4 ,publi%$ ,novemb]1 #aijg4 ,,cont5ts ,,page ,,introduction xi ,"p ,i ,,*apt] ,i4--,,"s ,,g5]al ,,explanations #c ,,an ,,invisible ,,_w-,,p[] -- ,,g5]at+ ,,electricity -- ,,:at ,a ,,boy ,,c ,,d -- ,,inexp5sive ,,tools -- ,,"s ,,practical ,,advice ,,*apt] ,,ii4--,,cells ,,& ,,batt]ies #ab ,,simple ,,& ,,inexp5sive ,,cells -- ,,h[ ,,to ,,make ,,cells ,,& ,,batt]ies -- ,a ,,plunge-,,batt]y -- ,a ,,/orage-,,batt]y -- ,,dry-,,cells ,,& ,,batt]ies ,,*apt] ,,iii4--,,pu%-,,buttons ,,& ,,swit*es #cc ,,h[ ,,to ,,make ,,pu%-,,buttons -- ,,swit*es ,,& ,,cut-,,outs -- ,,table-,,jack ,,swit*es -- ,,b9d+-,,po/s ,,& ,,connectors -- ,,lightn+-,,arre/]s ,,& ,,fuse-,,blocks -- ,,"s ,,practical ,,precautions ,,*apt] ,,iv4--,,magnets ,,& ,,induction-,,coils #ed ,,simple ,,& ,,horse%oe ,,magnets -- ,,induction-,,coils -- ,,an ,,electric ,,buzz] -- ,,electric ,,bells -- ,a ,,l>ge ,,induction-,,coil -- ,,circuit-,,int]rupt]s ,,*apt] ,v4--,,annunciators ,,& ,,bells #gh ,a ,,drum-,,s\nd] -- ,a ,,simple ,,annunciator -- ,a ,,d\ble ,,electric ,,bell -- ,,an ,,electric ,,horn -- ,,h[ ,,to ,,make ,a ,,burgl>-,,al>m -- ,,electric ,,call-,,signals -- ,,clock-,,al>ms -- ,a ,,d9+-,,table ,,call ,,*apt] ,,vi4--,,curr5t-,,detectors ,,& ,,galvanomet]s #ajb ,,h[ ,,to ,,make ,,detectors -- ,,an ,,a/atic ,,curr5t-,,detector -- ,,an ,,a/atic ,,galvanomet] -- ,a ,,tang5t ,,galvanomet] ,"p ,,ii ,,*apt] ,,vii4--,,electrical ,,resi/ance #abe ,,gov]n+ ,,! ,,electric ,,curr5t -- ,,ohm',s ,,law -- ,,resi/ance-,,coils ,,& ,,rheo/ats -- ,,h[ ,,to ,,make ,,simple ,,app>atus -- ,,liquid ,,resi/ance -- ,,importance ,,( ,,swit*es -- ,,uses ,,( ,a ,,h\se-,,curr5t -- ,,runn+ ,a ,,sew+-,,ma*9e1 ,,fan1 ,,or ,,toys -- ,,an ,,easy ,,me?od ,,= ,a ,,boy',s ,,use ,,*apt] ,,viii4--,,! ,,telephone #aef ,,vibratory ,,waves -- ,a ,,bladd] ,,telephone -- ,a ,,s+le 7,,receiv]7 ,,l9e -- ,,plan ,,( ,,in/allation -- ,a ,,d\ble-,,pole ,,receiv] -- ,,! ,,transmitt] -- ,,ano!r ,,=m ,,( ,,transmitt] -- ,,! ,,wir+ ,,sy/em -- ,a ,,telephone ,,induction-,,coil -- ,,an ,,in/allation ,,plan -- ,a ,,portable ,,app>atus ,,*apt] ,,ix4--,,l9e ,,& ,,wireless ,,telegraphs #aij ,a ,,gr\nd ,,telegraph -- ,,h[ ,,to ,,talk ,,f ,,h\se ,,to ,,h\se -- ,,! ,,morse ,,telegraph ,,code -- ,a ,,/ory ,,( ,,edison -- ,,h[ ,,detectives ,,us$ ,,! ,,code -- ,,wireless ,,telegraphy -- ,,its ,,true ,,"* -- ,,h[ ,a ,,boy ,,c ,,make ,a ,,practical ,,app>atus -- ,,receiv+ ,,& ,,s5d+ ,,poles -- ,,induction-,,coils1 ,,batt]ies1 ,,coh]]s ,,& ,,de-,,coh]]s1 ,,etc4 -- ,,work+ ,,plans ,,9 ,,detail -- ,a,,rograms ,,across ,,! ,,atlantic ,,&1 ,,p]haps1 ,,ar\nd ,,! ,,_w ,,*apt] ,x4--,,dynamos ,,& ,,motors #bbi ,,dep5d5ce ,,( ,,mod]n ,,electricity ,,^u ,,! ,,dynamo -- ,a ,,field ,,( ,,=ce ,,cutt+ ,,ano!r ,,field ,,( ,,=ce -- ,,v>ieties ,,( ,,dynamos -- ,,simpl] ,,=ms ,,( ,,g5]ators ,,& ,,motors -- ,,h[ ,,to ,,make ,a ,,uni-,,direction ,,curr5t ,,ma*9e -- ,,p]man5t ,,magnet1 ,,armature1 ,,%afts1 ,,:eels1 ,,etc4 -- ,a ,,small ,,dynamo -- ,,ma*9es ,,to ,,light ,,lamps1 ,,run ,,motors1 ,,etc4 -- ,a ,,split-,,r+ ,,dynamo -- ,a ,,small ,,motor -- ,,! ,,flat-,,b$ ,,motor -- ,,motors ,,( ,,o!r ,,types ,,*apt] ,,xi4--,,galvanism ,,& ,,electro-,,plat+ #bff ,a ,,fasc9at+ ,,use ,,( ,,electricity -- ,a ,,simple ,,electro-,,plat+ ,,outfit -- ,,! ,,sulphate ,,( ,,copp] ,,ba? -- ,,h[ ,,to ,,make ,,! ,,tank ,,& ,,o!r ,,app>atus -- ,a ,,v>iety ,,( ,,beautiful ,,& ,,useful ,,results -- ,,explanations ,,( ,,v>i\s ,,batt]ies -- ,,! ,,cleans+ ,,process -- ,,! ,,plat+-,,ba? -- ,,silv]-,,plat+ -- ,,gold-,,plat+ -- ,,nickel-,,plat+ -- ,,f9i%+ -- ,,electrotyp+ -- ,,practical ,,details ,,( ,,int]e/+ ,,"w ,,*apt] ,,xii4--,,miscellane\s ,,app>atus #bid ,,mak+ ,a ,,rot>y ,,glass-,,cutt] -- ,,to ,,smoo? ,,glass ,,edges -- ,,cutt+ ,,holes ,,9 ,,glass -- ,,anti-,,hum ,,device ,,= ,,metallic ,,l9es -- ,a ,,reel-,,c> ,,= ,,wire -- ,,insulators -- ,,jo9ts ,,& ,,splices -- 8,,gr\nds0 -- ,,! ,,edison ,,roa*-,,kill] -- ,,an ,,electric ,,m\se-,,kill] ,,*apt] ,,xiii4--,,frictional ,,electricity #cab ,,its ,,nature -- ,,limit$ ,,uses -- ,,simplicity ,,( ,,app>atus -- ,a 8,,wim%ur/ ,,influ5ce ,,ma*9e0 -- ,,mat]ials ,,requir$ -- ,,glass1 ,,t9-,,foil1 ,,sp9dles1 ,,uprights1 ,,:eels1 ,,etc4 -- ,a ,,l>ge ,,leyd5-,,j> -- ,,app>atus ,,= ,,int]e/+ ,,exp]im5ts -- ,,necessity ,,( ,,caution ,,*apt] ,,xiv4--,,=mul #cbg ,,acid-,,pro( ,,cem5ts -- ,,h>d ,,cem5t -- ,,s(t ,,cem5t -- ,,v ,,h>d ,,cem5t -- ,,cl>k',s ,,comp\nd -- ,,batt]y ,,fluid -- ,,glass ,,rubb+ -- ,,acetic ,,glue -- ,,insulators -- ,,non-,,conductors -- ,,insulat+ ,,v>ni% -- ,,batt]y ,,wax ,,*apt] ,,xv4--,,electric ,,light1 ,,heat ,,& ,,p[] #ccd 7,by ,joseph ,b4 ,bak]7 ,,! ,,"w ,,( ,,! ,,dynamo -- ,,! ,,electric ,,light -- ,,uses ,,( ,,! ,,arc-,,light -- ,,inc&esc5t ,,& ,,o!r ,,lamps -- ,,electric ,,heat -- ,,electric ,,furnaces -- ,,weld+ ,,metals -- ,,electric ,,c>-,,heat]s -- ,,h\sehold ,,uses -- ,,electric ,,p[] -- ,,p[] ,,f ,,wat]-,,:eels -- ,,trans=m]s -- ,,rot>y ,,conv]t]s -- ,,oil-,,swit*es -- ,,electric ,,traction -- ,,! ,,trolley-,,c> -- ,,! ,,cont9u\s-,,curr5t ,,motor -- ,,! ,,controll] -- ,,electric ,,locomotives -- ,,o!r ,,=ms ,,( ,,electric ,,traction ,a ,,diction>y ,,( ,,electrical ,,t]ms #cei ,,introduction ,if a h&y-book ( electricity l ?is _h fall5 into ! h&s ( ,?omas ,a4 ,edison :5 he 0 a newsboy on ! ,gr& ,trunk ,railway1 or :5 he 0 a telegraph op]ator1 he w\ld h dev\r$ x ) ! utmo/ eag]ness4 ,to be sure1 at t "t1 9 ! e>ly sixties1 all t we knew ( electricity & its applications c\ld h be5 told 9 a v brief compass4 ,x 0 an almo/ unkn[n field1 & ! crude =m ( ! telegraph !n 9 use repres5t$ its mo/ important application4 ,!re 7 no electric lights2 !re 0 no telephone or phonograph2 !re 7 no electric motors4 ,telegraph+1 itself1 0 a sl[ & difficult process4 ,all ! conditions 7 z f> remov$ z possible f ! broad field ( appli$ electricity indicat$ 9 ?is book4 ,b ?is does n mean t we h n[ accompli%$ all t !re is to be done4 ,on ! contr>y1 ! next half-c5tury w be full ( wond]ful advances4 ,?is makes x m ?an ev] ess5tial t we %\ld become acqua9t$ ) ! pr9ciples & pres5t conditions ( a sci5ce :i* is be+ appli$ m & m closely to ! "w ( e-day life4 ,x is necess>y to "k ?is f ! inside1 n simply f g5]al descriptions4 ,!ory is all v well1 b !re is no?+ l ma/]+ pr9ciples1 & !n apply+ !m & work+ out results = "o's self4 ,any active & intellig5t boy ) an inquir+ m9d w f9d a new _w op5$ to him 9 ! satisfaction ( mak+ electrical devices = himself accord+ to ! sugge/ions giv5 9 ?is book4 ,?is w %[ him ! reasons = ?+s 9 concrete =m1 w famili>ize him ) pr9ciples1 & w develop 8 me*anical +5uity4 ,he may be lay+ ! f\ndation = inv5tions ( 8 own or = pr(essional success 9 "s ( ! _m fields :i* electricity n[ (f]s4 ,"w ( ?is k9d br+s out :at is 9 "o1 & !re is no satisfaction great] ?an t ( w9n+ success by "o's own ef=ts4 ,! boy :o makes a pu%-button = 8 own home1 or builds 8 own telephone l9e or wireless telegraph plant1 or by 8 own +5uity makes electricity run 8 "m's sew+-ma*9e & d o!r home "w1 has le>n$ applications ( !ory :i* he w nev] =get4 ,! new _w :i* he w ent] is a mod]n fairyl& ( sci5ce1 = 9 ! use ( electricity he has add$ to himself ! control ( a p[]ful g5ie1 a will+ & mo/ useful s]vant1 :o w d 8 err&s or provide new play?+s1 :o w give him manual tra9+ & a va/ increase 9 g5]al k4 ,! cont5ts ( ?is book1 rang+ f ! prep>ation ( simple cells to ! mak+ ( dynamos & motors1 & ! delightful possibilities ( electro-plat+1 %[s ! ri*ness ( ! field :i* is made accessible by ,mr4 ,adams' practical explanations1 8 c>efully te/$ work+ plans1 & 8 num]\s & admirable draw+s--all ( :i* h be5 made = ?is book4 ,x is 9 keep+ ) ! practical "* ( ! ,electricity ,book t pa9s are tak5 ?r\gh\t to %[ ! simple/ & mo/ inexp5sive way ( *oos+ mat]ials & secur+ results4 ,! actual work+ out ( ^! directions c be done at v small exp5se4 ,fur!rmore1 !re ne$ be no conc]n :atev] z to possible dang] if ! book is read ) reasonable intellig5ce4 ,mr4 ,adams has tak5 pa9s to place dang]-signals :]ev] special precautions are advisable1 &1 z a fa!r ( boys :o are con/antly work+ ) electricity 9 8 laboratory1 he may be reli$ ^u z a safe & sure c\nsellor & guide4 ,:ile ?is book %[s boys :at !y c d !mselves1 its scope has be5 enl>g$ by ,mr4 ,bak]'s *apt] expla9+ briefly ! work+ ( electricity all ab\t u1 9 light & heat1 9 ! trolley-c>1 & o!r daily applications4 ,9 addition1 ,mr4 ,adams has prep>$ a ,diction>y ( ,electrical ,t]ms1 & ^! brief def9itions w be f\nd peculi>ly helpful 9 ! fir/ read+ ( ! book4 ,x is believ$ t !re is no book 9 ?is p>ticul> field comp>able to ,h>p]'s ,electricity ,book 9 its compreh5siv5ess1 practical "*1 & ! numb] & usefulness ( its illu/rations4 ,x foll[s ! successful ,out-door ,book = ,boys 9 ,h>p]'s s]ies ( ,practical ,books = ,boys1 & x w be foll[$ by ,h[ to ,und]/& ,electrical ,"w1 a book1 n ( in/ructions 9 mak+ electrical app>atus1 b ( explanations ( ! comm]cial uses ( electricity all ab\t u4 ,"p ,i ,,electricity ,,book ,,= ,,boys ,*apt] ,i ,,"s ,,g5]al ,,explanations ,we are liv+ 9 ! age ( electricity1 j z our fa!rs liv$ 9 ! age ( /eam4 ,electricity is ! _w-p[]1 ! mo/ p[]ful & t]rible ( nature's hidd5 =ces4 ,yet1 :5 man has le>n$ h[ to h>ness its fi]y en]gies1 electricity becomes ! mo/ docile & useful ( 8 s]vants4 ,unque/ionably1 electricity is to-day ! mo/ fasc9at+ & ! mo/ pr(itable field = ! inve/igator & ! inv5tor4 ,! be/ bra9s ( ! c\ntry are at "w ^u its problems4 ,new discov]ies are con/antly be+ record$1 & no labor is ?\ght too great if x b add its mite to ! sum total ( our k4 ,& yet1 ridicul\s z ! /atem5t may seem1 we d n "k :at electricity is4 ,we only "k c]ta9 ( its manife/ations--:at x c d4 ,all we c say is t x does our bidd+2 x propels our tra9s1 lights our h\ses & /reets1 w>ms u1 cooks = u1 & p]=ms a ?\s& & "o o!r tasks at ! turn ( a button or at ! ?ru/ ( a swit*4 ,b :at x is1 we d n "k4 ,electricity has no weight1 no bulk1 no color4 ,no "o has se5 x2 x _c be classifi$1 nor analyz$1 nor resolv$ into its ultimate elem5ts by any kn[n process ( sci5ce4 ,we mu/ cont5t ourselves ) describ+ x z "o manife/ation ( ! en]gy :i* fills ! univ]se & appe>s 9 a v>iety ( =ms--su* z heat1 light1 magnetism1 *emical aff9ity1 & me*anical motion4 ,9 all probability x is "o ( ^? ph5om5a ( nature t are de/9$ to rema9 =ev] secret4 ,?us x /&s 9 l9e ) gravitation1 magnetism1 ! active pr9ciple ( radium1 & ! p]petual motion ( ! sol> sy/em4 ,electricity 0 kn[n to ! e>ly ,greeks2 inde$1 x d]ives its "n f ! ,greek ^w = amb] 7electron74 ,= _m c5turies amb] 0 cr$it$ ) c]ta9 special or magical p[]s4 ,:5 x 0 rubb$ ) a flannel clo?1 8! hidd5 _s0 came out & laid hold ( small deta*$ objects1 su* z bits ( pap]1 ?read1 *ips1 or pi?-balls4 ,no "o c\ld expla9 ?is ph5om5on4 ,x 0 look$ ^u ) sup]/iti\s awe & ! amb] itself 0 reg>d$ z possess+ ! special attributes ( div9ity4 ,b z "t w5t on1 x 0 discov]$ t 9 v>i\s o!r sub/ances ?is my/]i\s attractive p[] c\ld be excit$1 at w1 ?r\gh ! ag5cy ( friction4 ,rubb+ a piece ( glass rod ) silk or lea!r g5]at$ an 8electricity0 id5tical ) t ( ! amb]2 or ! same result c\ld be obta9$ by excit+ h>d rubb] ) catsk94 ,! conclusion foll[$ t electricity 0 n a prop]ty ( ! special mat]ials employ$ to g5]ate x1 b t x came f )\t1 f t great res]voir ( en]gy1 ! atmosph]e4 ,!n came ,frankl9 ) 8 exp]im5t ( ! kite1 & ! inv5tion ( ! ,leyd5-j> & ! *emical production ( ! electric fluid by means ( batt]ies4 ,x 0 %[n t ! prop]ties ( ! new & /range =ce 7 ! same1 :e!r x 0 produc$ by ! /atic 7frictional7 process or by ! galvanic 7*emical7 me?od4 ,electrical sci5ce z a sci5ce1 _h begun4 ,& yet1 = _m ye>s1 electricity 0 h>dly m ?an a sci5tific toy4 ,x 0 n suppos$ to possess any practical usefulness4 ,! ent]ta9+ exp]im5ts ) ! /atic ma*9e & ! ,leyd5-j> 7*apt] xiii47 7 conf9$ to ! laboratory & ! lecture hall4 ,electricity 0 an amus+ display ( unkn[n en]gy1 b no "o ev] dream$ t x c\ld ev] be made to s]ve ! practical ends ( life4 ,x 0 n until ab\t #ahej t electrical sci5ce became any?+ m ?an a "n4 ,! galvanic & voltaic batt]ies 7*apt] ii47 op5$ ! way = 8curr5t0 electricity1 :i* fl[$ cont9u\sly1 in/ead ( jump+ & disappe>+ l ! sp>k f a ,leyd5-j>4 ,:5 ! cont9u\s curr5t became an e/abli%$ fact1 ! telegraph & telephone head$ ! l9e ( a long s]ies ( developm5ts4 ,f9ally1 ! g5]ation ( electricity 9 great] volume1 & *eaply1 made possible ! application ( its p[] = heat+1 light1 traction1 & ! o!r =ms ( activity 9 :i* x n[ does s l>ge a %>e ( ! _w's "w4 ,h[ electricity works is a "q (t5 ask$1 b n easily answ]$4 ,!re are c]ta9 s-call$ laws1 b we %all be/ arrive at a conclusion by simply /at+ a few ( ! facts t h be5 e/abli%$ ?r\gh ! obs]vation & inve/igation ( sci5ti/s & electrical eng9e]s4#a #a ,explanations ( any te*nical names or phrases us$ 9 ! text w be f\nd 9 ! simple diction>y ( electrical t]ms :i* appe>s z an app5dix4 ,= example1 electricity is always al]t1 ready to move1 & cont9ually on ! look\t = a *ance to obta9 its fre$om4 ,x w nev] g ! longe/ way r\nd if !re is a %ort cut2 & x w heat1 light1 or fuse any?+ 9 its pa? t is too weak to c>ry or resi/ x4 ,= ?is reason1 x mu/ be g5]at$ 9 small volume--t is1 j suffici5t to d ! "w requir$ ( x4 ,if produc$ 9 l>g] volume1 x mu/ be held 9 *eck by resi/ance1 & only s mu* all[$ to escape z may be ne$$ = ! specifi$ "w4 ,aga91 :5 electricity is g5]at$ ?is mu/ be done 9 "o ( two ways--by friction or *emically4 ,b 9 bo? processes !re mu/ be air surr\nd+ ! g5]ators1 & ! fluid mu/ be ( a nature ?r\gh :i* oxyg5 & hydrog5 c circulate freely4 ,wat] fluids are suitable = ?is purpose1 b oils _c be us$1 z !y conta9 hydro-c>bon 9 l>ge quantities & are non-conductors4 ,batt]ies are *emical g5]ators1 dynamos are magneto-electric1 & /atic ma*9es are frictional4 ,n[ ! !ory is t electricity is drawn f ! e!r &1 9 its normal /ate1 is quiet4 ,if x be di/urb$ & collect$ by me*anical or *emical means1 x is always on ! al]t to escape & aga9 take its place 9 ! atmosph]e4 ,z its volume is increas$1 s its en]gy to get away is multipli$1 & ?is en]gy may be trans=m$1 at w1 into p[]1 heat1 or light4 ,to express ! idea 9 ! simple/ language1 x wants to g home1 & 9 its ef=t to d s x expresses itself 9 ! =m ( /or$-up p[]1 precisely l wat] beh9d a dam4 ,x is = man's cunn+ bra9 to devise all sorts ( tasks t ?is p[] mu/ p]=m be=e x c ga9 its release4 ,x c't g home until its "w is done4 ,ne>ly e boy has exp]im5t$1 at "o "t or ano!r1 ) electricity & electrical app>atus1 & :e!r x 0 ) "s ( ! simple frictional or galvanic toys1 or ) ! m complicat$ induction-coils & motors1 he has und\bt$ly f\nd x a mo/ int]e/+ amusem5t & an ev] new & wid5+ field = /udy4 ,!n aga91 _m boys w\ld l to "k some?+ ab\t simple electrical app>atus & h[ to make & use x4 ,b 8 s*ool-books relat+ to ! g5]al subject ( electricity are h>dly def9ite en\gh to s]ve z a practical manual4 ,& yet !re are _m ?+s 9 ! way ( electrical ma*9]y & equipm5t t a boy c easily con/ruct & use4 ,9 ?is book x is my purpose to %[ him j :at c be done ) ! aid ( ! tools t are usually 9 8 possession4 ,:ile "s ?+s may h to be pur*as$ f an electrical supply-h\se or o!r s\rces1 !re is /ill mu* mat]ial to be f\nd ab\t ! h\se t may be put to good use by ! amateur electrician4 ,x is n possible or desirable to describe e v>iety ( electrical equipm5t4 ,we mu/ conf9e ourselves to app>atus :i* c be readily und]/ood & op]at$4 ,! 8practical0 idea is ! "o to be borne 9 m9d4 ,?is book %[s a boy h[ to use 8 bra9s & ! simple tools & mat]ial t may be at 8 comm&4 ,c>e & ?\ght 9 ! con/ruction ( ! app>atus are ! important qualifications = success4 ,! in/ructions are giv5 9 ! cle>e/ possible language2 ! diagrams & draw+s are intelligible to any "o :o w take ! tr\ble to /udy !m4 ,if y\r f9i%$ app>atus does n "w prop]ly1 read ! description aga9 & see if y h n made "s error4 ,a misplac$ or brok5 wire1 a wrong connection1 or a %ort circuit w mean all ! diff]5ce betwe5 success & failure4 ,save 9 "o %ort *apt]1 /atic or frictional electricity 7see ,app5dix7 is n consid]$2 = outside ( laboratory exp]im5t+ & electro-m$ical app>atus1 frictional electricity is b a toy--int]e/+ & useful :5 g5]at$ 9 small volume1 b v dang]\s & difficult ( control :5 9 great volume4 ,= example1 ! bolt ( lightn+ is b ! _m times multipli$ sp>k /or$ 9 ! ,leyd5-j> by ! /atic ma*9e4 ,= all practical purposes1 galvanic electricity1 9 its v>i\s phases ( direct & alt]nat+ curr5t1 meets ! requirem5ts ( man4 ,) ! improv$ app>atus & ! rapid advancem5t along ! l9e ( inv5tion1 electricity is z easily controll$ to-day z /eam--9 fact1 its economical use is ev5 m fully "u control & its adaptability m practical4 ,9 ! foll[+ pages !re are probably illu/rations & descriptions ( _m ?+s t w seem /range to ! boy :o has n he>d ( !m2 b if a book 7 writt5 ea* ye> on ! subject ( electricity1 e new "o w\ld include pr9ciples & facts n kn[n be=e4 ,! field ( electrical rese>* is s broad & s _m are work+ 9 x t new discov]ies are be+ made cont9ually4 ,to ^? famili> ) ! application ( electricity1 x is cle>ly evid5t t1 z yet1 we are only beg9n+ to deal ) ?is unkn[n =ce4 ,= g5]ations to come1 developm5ts w take place & inv5tion foll[ inv5tion until electricity assumes its rightful place z ! motive =ce ( ! _w4 ,to ! boy int]e/$ 9 ?is subject a wide field is op51 & ! y\? ( to-day1 :o are tak+ up ?is /udy1 are de/9$ to become ! successful electrical eng9e]s & inv5tors ( ! future4 ,!re is no bett] education = any boy1 9 ! application & pr9ciples ( electricity1 ?an to beg9 at ! v bottom ( ! ladd] & climb up1 con/ruct+ & /udy+ z he progresses4 ,:5 he attempts to design m te*nical & difficult app>atus ! lessons le>n$ 9 a practical way w be ( ine/imable value1 great] by f> ?an any !oretical pr9ciples d$uc$ f books2 he kn[s 8 subject f ! gr\nd up2 he und]/&s 8 ma*9e because he has con/ruct$ x ) 8 own h&s4 ,z ,i h said already1 ! necess>y tools are few 9 numb] & n exp5sive4 ,!y may include a hamm]1 a plane1 awls1 pli]s1 wire-cutt]s1 & t9-%e>s4 ,! raw mat]ial is also *eap--lead1 t91 wire1 wood1 & simple *emicals4 ,! laboratory may be a corn] 9 ! attic1 or ev5 9 a boy's b$room1 s f> z ! f9] "w is conc]n$1 :ile ! hamm]+ & saw+ may be done 9 ! cell>4 ,! o!r be/ plan1 ( c\rse1 is to get ! use ( a sp>e room :i* may be fitt$ ) %elves1 draw]s1 & appliances = s]i\s "w4 ,to en?usia/ic beg9n]s1 z well z to ^? :o h _h "s exp]i5ce 9 electricity1 a ne$$ w>n+ may be giv5 9 ?ree words3 8,take no *ances40 ,electricity1 ! subtle1 /eal?y1 & ev]-al]t =ce1 w (t5 deal a bl[ :5 lea/ expect$4 ,= t reason1 a boy %\ld nev] m$dle ) a high-t5sion curr5t or ) ! ma9s f dynamos4 ,! curr5t 9 ! h\se1 us$ = light+1 cook+1 or heat+ purposes1 is always an attractive po9t = ! "y electrician1 b ! wires %\ld nev] be t\*$ 9 any way4 ,too _m accid5ts h happ5$1 & ! conductors1 lamp-sockets1 & plugs %\ld be c>efully avoid$4 ,! boy %\ld keep /rictly to 8 batt]ies1 or small dynamos run by wat]-p[] f a faucet2 9 no case %\ld ! wire f p[]-h\ses be tamp]$ )4 ,"o little kn[s :at a curr5t x may be c>ry+ & :at a dea?-deal+ =ce x possesses4 ,always be> 9 m9d t a nak$ wire fall+ f a trolley equipm5t c>ries en\gh =ce to kill any?+ x /rikes4 ,special att5tion is call$ to ! diction>y ( electrical t]ms giv5 9 ! ,app5dix4 ,! "y /ud5t %\ld nev] pass ov] a ^w or a t]m t he does n ?or\ghly und]/&4 ,always look x up at once & e "t x occurs1 until y are sure t its mean+ is fix$ 9 y\r m9d4 ,?is is an education 9 itself1 at lea/ s f> z ! !oretical k ( our subject is conc]n$4 ,z a f9al ^w1 ,i %\ld l e boy int]e/$ 9 electricity to he> :at ,?omas ,a4 ,edison once said to me :5 ,i 0 a boy work+ 9 8 laboratories4 ,i (t5 recall x :5 ?+s d n g j "r at fir/4 ,i ask$ ! great inv5tor "o day if inv5tion 0 n made up l>gely ( inspiration4 ,he look$ at me quizzically = a mom5t1 & !n repli$3 8,my boy1 ,i h little use = a man :o works on inspiration4 ,inv5tion is two p>ts inspiration & n9ety-eight p] c5t4 p]spiration40 ,y w nev] get :at y are aft] unless y "w h>d = x4 ,y mu/ /ick to x until y produce results4 ,if ! hi/ory ( ! _w's mo/ valuable inv5tions c\ld be fully kn[n1 ! fact w\ld be cle>ly e/abli%$ t ! vital sp>k ( inspiration is b ! />t+-po9t4 ,!n foll[ ! days1 weeks1 & sometimes ye>s ( indu/ri\s toil1 failures1 & disappo9tm5ts1 until f9ally ! desir$ end is atta9$4 ,"o mu/ "w = success2 !re is no o!r means ( w9n+ x4 ,z ! table ( cont5ts %[s1 ,"p ,i4 ( ?is book expla9s pr9ciples & ! simpl] =ms ( electrical appliances4 ,f ?is we advance to ,"p ,,ii41 :i* deals ) m complex =ms ( electrical "w1 mo/ ( :i*1 h[ev]1 are )9 ! rea* ( intellig5t boys :o h foll[$ ! *apt]s c>efully f ! fir/4 ,9 a f9al *apt] we h simple explanations ( ! great comm]cial uses ( electricity1 :i* we see all ab\t u1 al?\gh v few ( u h a cle> idea z to _! op]ation4 ,*apt] ,,ii ,,cells ,,& ,,batt]ies ,simple ,cells ,9 ord] to g5]ate electricity x is necess>y to employ cells1 batt]ies1 or dynamos4 ,s9ce ! con/ruction & op]ation ( a dynamo is some:at intricate1 x w be bett] to />t ) ! simpl] me?ods ( electric g5]ation1 & s "w up to ! m complicat$ =ms4 ,= small app>atus1 su* z electric bells & light magnets & motors1 ! z9c-c>bon-sal-ammoniac cell w answ] v well2 b = l>g] ma*9]y1 :]e m curr5t is requir$1 ! blue/one & ! bi-*romate batt]ies w be f\nd necess>y4 ,illu/ration3 ,,fig4 #a ,,fig4 #b ,,fig4 #c ,,fig4 #e ,,simple ,,batt]y ,,elem5ts ,a simple & inexp5sive cell may be made f electric-light c>bons1 ) ! copp] coat+ remov$1 & p5cils ( z9c1 su* z are us$ = electric-bell batt]ies & :i* c be pur*as$ = five c5ts ea*4 ,copp] wire is to be b\nd ar\nd ! top ( ea* p5cil ( c>bon & z9c1 & firmly fa/5$ ) ! pli]s1 s t x w n pull (f or become deta*$4 ,x w be well to cut a groove ) a file ar\nd ! top ( bo? ! c>bon & z9c1 into :i* ! wire w fit4 ,! elem5ts %\ld !n be clamp$ betwe5 two pieces ( wood & held ) screws1 z %[n 9 ,fig4 #a4 ,a m effici5t c>bon pole is made by /rapp+ six or m %ort c>bon p5cils ar\nd "o long "o1 z %[n 9 ,fig4 #c4 ,! %ort pieces ( electric-light c>bons are b\nd to ! longe/ c>bon ) heavy ela/ic b&s1 or cotton /r+ dipp$ 9 p>aff9e or wax1 to make ! cotton imp]vi\s to wat] & ! sal-ammoniac solution4 ,ano!r arrangem5t ( elem5ts is %[n 9 ,fig4 #b1 :]e a z9c rod is susp5d$ betwe5 two c>bons1 ! c>bons be+ connect$ by a wire t mu/ n t\* ! z9c4 ,a fruit-j>1 or a wide-neck$ pickle-bottle1 may be employ$ = a cell1 b be=e ! solution is p\r$ 91 ! upp] edge ( ! glass %\ld be coat$ ) p>aff9e4 ,?is %\ld be melt$ & appli$ ) a bru%1 or ! edge ( ! glass dipp$ 9 ! p>aff9e4 ,! solution is made by dissolv+ f\r ounces ( sal-ammoniac 9 a p9t ( wat]1 & ! j> %\ld be fill$ ?ree-f\r?s full4 ,9 ?is solution ! c>bons & z9c may be susp5d$1 z %[n 9 ! illu/ration 7,fig4 #d7 ( ! sal-ammoniac cell4 ,! wood clamps keep ! c>bon & z9c toge!r1 & ! ext5d+ ends re/ on ! top ( ! j> & hold ! poles 9 susp5sion4 ,plates ( z9c & c>bon may be clamp$ on ei!r side ( a squ>e /ick & susp5d$ 9 ! sal-ammoniac solution1 z %[n 9 ,fig4 #e1 tak+ c>e1 h[ev]1 t ! screws us$ = clamp+ d n t\* ea* o!r4 ,if "o cell is n suffici5tly p[]ful1 sev]al ( !m may be made & c\pl$ up 9 s]ies--t is1 by c>ry+ ! wire f ! z9c ( "o to ! c>bon ( ! next cell1 & s on to ! end1 tak+ c>e t ! wire f ! c>bon 9 ! fir/ cell & t f ! z9c ( ! la/ cell w be ! ones 9 h&1 z %[n 9 ,fig4 #f4 ,?is con/itutes a batt]y4 ,be sure & keep ! ends ( ! wire ap>t1 to prev5t galvanic action & to save ! p[] ( ! batt]ies4 ,?is batt]y is an excell5t "o = bells & small exp]im5tal "w1 & :5 inactive ! z9cs are n eat5 away 7z !y w\ld be if susp5d$ 9 a bi-*romate solution71 = corrosion takes place only z ! electricity is requir$1 or :5 ! circuit is clos$4 ,a s]ies ( batt]ies ( ?is description w la/ ab\t twelve mon?s1 if us$ = a bell1 & at ! end ( t "t w only require a new z9c & fre% solution4 ,! cell 9 :i* ! plates %[n 9 ,fig4 #e are us$ may conta9 a bi-*romate solution2 & = exp]im5tal "w1 :]e electricity is requir$ = a %ort "t only1 ?is w produce a /rong] curr5t4 ,b rememb] t ! solution eats ! z9c rapidly1 & ! plates mu/ be remov$ z soon z y h f9i%$ us+ !m4 ,! bi-*romate solution is made by sl[ly p\r+ f\r ounces ( comm]cial sulphuric acid into a qu>t ( cold wat]4 ,?is %\ld be done 9 an e>!n j>1 s9ce ! heat g5]at$ by add+ acid to wat] is en\gh to crack a glass bottle4 ,nev] p\r ! wat] into ! acid4 ,:5 ! solution is ab\t cold1 add f\r ounces ( bi-*romate ( pota%1 & %ake or mix x occasionally until dissolv$2 !n place x 9 a bottle & label x3 ,,bi-,,*romate ,,batt]y ,,fluid ,,poison ,be=e ! z9cs are imm]s$ 9 ! bi-*romate solution !y %\ld be well amalgamat$ to prev5t ! acid f eat+ !m too rapidly4 ,! amalgamat+ is done by imm]s+ ! z9cs 9 a dilut$ solution ( sulphuric acid = a few seconds1 & !n rubb+ m]cury 7quicksilv]7 on ! surfaces4 ,! m]cury w adh]e to ! *emically clean$ surfaces ( any metal except iron & /eel1 & s prev5t ! corrod+ action ( ! acid4 ,d n get on too mu* m]cury1 b only en\gh to give ! z9c a ?9 coat1 s t x w pres5t a silv]y or %9y surface4 ,a two-fluid cell is made ) an out] glass or porcela9 j> & an inn] por\s cup ?r\gh :i* ! curr5t c pass :5 ! cup is wet4 ,fig4 #g4 ,illu/ration3 ,,fig4 #d ,illu/ration3 ,,fig4 #g ,illu/ration3 ,,fig4 #h ,illu/ration3 ,,fig4 #f ,a por\s cup is an unglaz$ e>!n receptacle1 simil> to a fl[]-pot1 ?r\gh :i* moi/ure w pass sl[ly4 ,! por\s cup conta9s an amalgamat$ plate ( z9c imm]s$ 9 a solution ( dilut$ sulphuric acid--"o ounce to "o p9t ( wat]4 ,! out] cell conta9s a saturat$ solution ( sulphate ( copp] 9 :i* a cyl9drical piece ( ?9 %eet-copp] is held by a ?9 copp] /rap1 b5t ov] ! edge ( ! out] cell4 ,a few lumps or cry/als ( ! copp] sulphate1 or blue/one1 %\ld be dropp$ to ! bottom ( ! j> to keep ! copp] solution saturat$ at all times4 ,:5 n 9 use1 ! z9c %\ld be remov$ f ! inn] cell & wa%$ (f2 & if ! batt]y is n to be employ$ = sev]al days1 x w\ld be well to p\r ! solutions back into bottles & wa% ! sev]al p>ts ( ! batt]y1 s t x may be fre% & /rong :5 next requir$4 ,:5 9 action1 ! solutions 9 bo? cups %\ld be at ! same level1 & be c>eful nev] to all[ ! solutions to get mix$ or ! copp] solution to t\* ! z9c4 ,coat ! top ( ! por\s cell ) p>aff9e to prev5t cry/allization1 & also to keep x clean4 ,take great c>e1 9 h&l+ ! acid solutions1 to we> old clo!s1 & d n let ! liquids spatt]1 = !y are /rong en\gh to eat holes 9 almo/ any?+1 & ev5 to *> wood4 ,! two-fluid cells are mu* /rong] ?an ! "o-solution cells1 & connect$ up 9 s]ies !y w develop consid]able p[]4 ,= telegraph-s\nd]s1 l>ge electric bells1 & z accumulators = *>g+ /orage-batt]ies1 ! gravity-cell w give ! mo/ satisfactory results4 ,! "o %[n 9 ,fig4 #h consi/s ( a deep glass j>1 ?ree /rips ( ?9 copp] rivet$ toge!r1 & a z9c cr[-foot t is caught on ! upp] edge ( ! glass j>4 ,^! p>ts w h to be pur*as$ at a supply-h\se1 toge!r ) a p\nd or two ( sulphate ( copp] 7blue/one74 ,to set up ! cell1 place ! copp] at ! bottom & drop 9 en\gh ( ! cry/als to g5]\sly cov] ! bottom1 b d n try to imb$ ! metallic copp] 9 ! cry/als2 !n fill ! j> half full ( cle> wat]4 ,9 ano!r j> dissolve two ounces ( sulphate ( z9c 9 en\gh wat] to complete ! fill+ ( ! j> to )9 two in*es ( ! top2 !n hang ! z9c cr[-foot on ! edge ( ! j> s t x is imm]s$ 9 ! liquid & is susp5d$ ab\t ?ree in*es above ! top ( ! copp] /rip4 ,! wire t leads up f ! copp] %\ld be insulat$ ) a wat]-pro( coat+ & well cov]$ ) p>aff9e4 ,a numb] ( ^! cells may be connect$ 9 s]ies to increase ! p[] ( ! curr5t1 & = a work+-batt]y ?is w %[ a high effici5cy4 ,note t at fir/ ! solutions w m+le4 ,to sep>ate !m1 jo9 ! two wires & />t ! action2 !n1 9 a few h\rs1 a divid+ l9e w be se5 betwe5 ! :ite1 or cle>1 & ! blue solutions1 & ! action ( ! cell w be /rong]4 ,aft] long-cont9u$ use x may be necess>y to draw (f "s ( ! cle> z9c sulphate1 or top solution1 & replace x ) pure wat]4 ,! action ( ! acids r$uces ! metallic z9c to z9c sulphate & deposits metallic copp] on ! ?9 copp] /rips1 & 9 ?is process an electrical curr5t is g5]at$4 ,a ,plunge-batt]y ,:5 two or m cells 79 :i* sulphuric acid1 bi-*romate ( pota%1 or o!r /rong electropoions are employ$7 are c\pl$ 9 s]ies1 x w\ld be well to arrange ! copp] & z9c1 or ! z9c & c>bon1 poles on a bo>d1 s t all ( !m may be l[]$ toge!r into ! solutions conta9$ 9 ! sev]al j>s4 ,a simple arrangem5t ( ?is k9d is %[n 9 ,fig4 #i1 :]e a rack is built = ! j>s & at ! top ( ! end bo>ds a project+ piece ( wood1 support$ by a bracket1 is made fa/4 ,a n>r[ piece ( bo>d ne>ly ! l5g? ( ! j>-rack is fitt$ ) ! batt]y-poles1 z %[n at ,fig4 #i ,a4 ,! c>bon & z9c1 or copp] & z9c1 poles are atta*$ to small blocks ( wood 7z describ$ = ,fig4 #e71 & ?is block 9 turn is fa/5$ to ! "u side ( ! bo>d ) brass screws4 ,! poles ( ! cells are to be connect$ 7z expla9$ 9 ,fig4 #f71 & :5 ! batt]y is 9 use ! poles are imm]s$ 9 ! solution conta9$ 9 ! j>s4 ,:5 ! batt]y is at re/ ! n>r[ bo>d %\ld be lift$ up & plac$ on ! project+ arms ( ! rack1 s t ! liquid on ! poles may dra9 into ! j>s directly und]nea?4 ,"o or m ( ^! batt]y-racks may be con/ruct$1 b !y _c be made to hold conv5i5tly m ?an f\r or six cells ea*2 if m cells are requir$1 ^? conta9$ 9 ea* rack mu/ be c\pl$ up 9 s]ies4 ,illu/ration3 ,,fig4 #i ,illu/ration3 ,,fig4 #aj ,a simpl] plunge-batt]y is %[n 9 ,fig4 #aj4 ,a cell-rack is made ( wood & giv5 two or ?ree coats ( %ellac4 ,! n>r[ bo>d 7to ! "u side ( :i* ! batt]y-poles are atta*$1 z expla9$ 9 ,fig4 #i7 is hung on *a9s or flexible wires1 :i* 9 turn are made fa/ to an iron %aft runn+ ! entire l5g? ( ! cell-rack4 ,?is %aft is ( half-in* r\nd iron1 & is held 9 place1 at "o end1 by a p9 & wa%]2 :ile at ! o!r ! end is fil$ ) a squ>e %\ld]1 & a h&le & crank is fitt$ to x1 s t ! %aft may be turn$4 ,a small hole1 made at ! side ( ! crank :5 x is hang+ d[n1 w receive a h>d-wood peg1 or a /eel nail1 & ?is w prev5t ! crank f slipp+ :5 ! bo>d hold+ ! poles is rais$4 ,if a ge>-:eel & tongue c be _h to fit on ! %aft1 x w !n be possible to *eck ! %aft securely at any "p ( a turn ( ! crank4 ,! batt]y-poles are to be connect$ 9 s]ies along ! top ( ! portable bo>d1 z expla9$ = ,fig4 #f4 ,:5 two or m ( ^! plunge-batt]ies are us$ at "o "t1 ! wire f ! c>bon ( "o is to be connect$ ) ! z9c pole ( ! next1 & s on4 ,! wire f ! z9c ( ! fir/ batt]y1 & ! wire f ! c>bon ( ! la/ batt]y1 w be ! ones available = use4 ,a ,/orage-batt]y ,:5 m curr5t is desir$ ?an ! simple batt]ies w give1 a /orage-batt]y %\ld be employ$ z an accumulator4 ,?is result c be secur$ by c\pl+ prim>y cells 9 s]ies1 s t !y w be con/antly g5]at+ & fe$+ ! batt]y4 ,/orage-batt]ies are too heavy to be %ift$ ab\t1 l s+le cells or small plunge-batt]ies2 !y %\ld be plac$ 9 a cell>1 :]e ! *>g+ or prim>y cells c be locat$ close by1 &1 unless positively necess>y1 ! batt]y ( cells & ! accumulator %\ld n be mov$4 ,) suffici5tly l>ge insulat$ wires 7,nos4 #ab1 #ad1 or #af copp]71 ! curr5t may be c>ri$ to any "p ( ! h\se = use 9 v>i\s ways--su* z runn+ a light motor or a fan1 light+ a lamp-circuit1 or fus+ metals & *emicals = exp]im5tal purposes4 ,:ile ! batt]y to be describ$ is n a light "o 9 weight1 nor z economical z ! improv$ new ,edison /orage-batt]y1 x is a good & con/ant "o1 &1 if n ov]*>g$ or abus$1 w la/ = sev]al ye>s4 ,! compon5t p>ts ( a /orage-batt]y are lead 9 metallic & *emical =m1 ! electrolyte1 or fluid1 9 :i* ! plates are imm]s$1 & ! wat]-tight & *emical-pro( cell or conta9]4 ,f a plumb]1 a supply-h\se1 or a lead-works1 obta9 a quantity ( ?ree-eigh? by "o-qu>t]-in* /rip-lead ( ! k9d call$ *emical1 or desilv]iz$2 also a l>g] quantity ( lead-tape1 "o-sixty-f\r? ( an in* ?ick & ?ree-eigh?s ( an in* wide4 ,?is la/ is also kn[n z torp$o-lead1 & is kept by electrical supply-h\ses4 ,if ! ?ree-eigh?s by qu>t]-in* /rip-lead _c be _h1 !n pur*ase eight or t5 p\nds ( heavy %eet-lead1 &1 ) a t9-%e>s1 divide x into /rips ?ree-eigh?s ( an in* wide & tw5ty-n9e in*es long1 tak+ c>e to cut x ( uni=m wid? & ) true edges4 ,f h>d-wood ?ree-eigh?s or half an in* ?ick1 cut a block six by sev5 in*es & make f\r c\nt]sunk holes 9 x1 s t x may be screw$ fa/ to a table or b5*1 z %[n 9 ,fig4 #aa ,a4 ,ar\nd ?is ! lead /rips %\ld be %ap$ & beat5 at ! corn]s to make ! angles %>p4 ,f ! ?ree-eigh?s by qu>t]-in*1 or %eet-lead /rips1 make sev5 frames z %[n 9 ,fig4 #ab4 ,?is is done by b9d+ a /rip ( ! lead ar\nd ! block1 z %[n at ,fig4 #aa ,b4 ,:]e ! ends come toge!r ins]t a %ort piece ( lead1 ?ree-eigh?s or half-in*1 z %[n at ,fig4 #ab ,a1 & sold] x fa/4 ,a sold]+-iron may be heat$ ) a ,buns5-burn] gas-flame or 9 a *>coal fire4 ,h[ev]1 if gas is available1 x w\ld be bett] to use ! blue flame f a ,buns5 burn] & direct ! hot bla/ directly on ! "w ) a bl[-pipe1 & s fuse ! lead po9ts toge!r4 ,aft] a little practice ) ! bl[-pipe x w be us$ = _m pieces ( "w 9 pref]5ce to ! sold]+-iron4 ,if ! %eet-lead is us$ = ! frames 9 place ( ! ?ree-eigh?s by qu>t]-in* /rips1 two or ?ree /rips w h to be tak51 s z to build up ! b& ( ! frame to ab\t a qu>t] ( an in* 9 ?ickness4 ,:5 sold]$ toge!r1 or fus$ at ! edges1 ^! built-up frames w be z rigid z ! solid metal4 ,illu/ration3 ,,fig4 #aa ,illu/ration3 ,,fig4 #ab ,illu/ration3 ,,fig4 #ac ,n[ cut a numb] ( /rips ( ! ?9 lead-tape six in*es & a half long1 & o!rs t w necess>ily be some:at long]1 = ea* frame is to be fill$ ) /raight & crimp$ pieces1 z %[n 9 ,fig4 #ac4 ,if !re is a flut+-iron 9 ! h\se1 ! crimp+ may be done 9 ! brass ge>s at "o end ( ! ma*9e4 ,or two :eels may be cut f h>d-wood ) a fret-saw1 & made fa/ to a block ) screws1 z %[n 9 ,fig4 #ad4 ,a h&le1 atta*$ to "o :eel1 w make x possible to turn ! ge>s2 & !y %\ld be plac$ j f> en\gh ap>t to all[ ! tape to pass ?r\gh )\t te>+ or squeez+4 ,put a wa%] betwe5 ! :eel & ! block to prev5t friction4 ,:5 a frame is 9 ! position %[n 9 ,fig4 #ac1 & ly+ on a piece ( slate or flat /one1 y w fir/ put 9 a crimp$ piece ( tape1 z %[n at ,fig4 #ac ,a1 & "u ?is arrange a /raight piece 7,fig4 #ac ,b72 !n1 ) ! bl[-pipe & flame1 fuse fa/ to ! frame & cat* ! flutes ( ! crimp$ piece to ! /raight "o e in* or two4 ,add alt]nate crimp$ & /raight /rips until ! frame is fill$ & pres5ts ! appe>ance ( ,fig4 #ac4 ,:5 ! sev5 frames are ready1 lay ?ree ( !m aside = ! positives & f\r = ! negatives4 ,note t ! positives are r$ & ! negatives a d>k yell[ :5 !y are fill$ ) ! active mat]ial4 ,!re are sev]al me?ods ( deposit+ ! active mat]ial 9 ! me% or net-"w ( ! plates1 b "s ( !m are too te*nical1 o!rs too complicat$1 & /ill o!rs require *>g+ ma*9]y4 ,! foll[+ plan w be ! simple/ & easie/ = ! amateur3 ,at a pa9t-/ore1 or f a :olesale druggi/1 obta9 sev]al p\nds ( oxide ( lead 7r$-lead7 & a simil> quantity ( li?>ge 7yell[-lead74 ,9 an e>!n vessel1 or l>ge j>1 make a solution compos$ ( wat]1 tw5ty ounces1 & comm]cial sulphuric acid1 two ounces4 ,?is is ! mixture commonly kn[n z 8"o to t540 ,place "s r$-lead 7dry7 9 an old saucepan or s\p-plate1 & add a little ( ! acid solution3 !n1 ) an old table-knife or small tr[el1 mix ! lead into a /iff pa/e1 l s(t putty4 ,d n get x too ?9 or x w run2 nor too ?ick1 z !n x w n prop]ly adh]e to ! lead-me% ( ! frames4 ,) ! frame ly+ on its side1 pla/] 9 ! r$ composition betwe5 ! flutes & fill up ! frame solid ) x4 ,treat all ?ree ( ! positive frames 9 ! same mann]1 tak+ c>e t ! expos$ surfaces ( ! composition-fill+ is smoo? & flu% ) ! edges ( ! lead frame & me%4 ,d n di/urb ^! plates = a :ile1 b let !m rema9 9 position1 s z to set & p>tially dry4 ,add acid solution to ! yell[-lead 9 a simil> mann]1 & fill ! f\r negative plates4 ,:5 p>tially dry1 ! plates w be ready to comb9e 9 a pile4 ,illu/ration3 ,,fig4 #ad ,illu/ration3 ,,fig4 #ae ,illu/ration3 ,,fig4 #af ,illu/ration3 ,,fig4 #ag ,at a supply-h\se obta9 "s %eets ( cellul\s fibre1 ?ree-sixte5?s ( an in* ?ick1 or "s asbe/os clo?4 ,if nei!r c be _h1 !n soak "s pieces ( ord9>y br[n c>d-bo>d 9 a solution ( silicate ( soda & let !m dry4 ,lay a negative 7yell[7 plate on ! table ) ! lug at ! left 7,fig4 #ac ,c74 ,on ?is place a squ>e ( ! fibre1 asbe/os1 or c>d-bo>d2 & on top ( x lay a positive 7r$7 plate ) ! lug at ! "r side4 ,cont9ue 9 ?is mann] until ! sev5 plates are /ack$1 ! f\r negative lugs be+ at ! left & ! ?ree positives at ! "r4 ,tie ! plates securely toge!r ) cotton /r+ b\nd ab\t !m 9 bo? directions2 !n /& ! pile up s t ! lugs are at ! top1 z %[n at ,fig4 #ae1 ) e alt]nate lug 9 an opposite direction4 ,obta9 two lead b>s ?ree-eigh?s ( an in* squ>e1 or cut /rips f ! %eet-lead & sold] !m toge!r1 turn+ ! ends z %[n at ,fig4 #ac ,d4 ,drop "o ( ^! b>s into ! lugs ( ! positive plates1 z %[n 9 ,fig4 #ae ,h1 & sold] x fa/ at ! ?ree unions4 ,repeat ?is ) ! o!r b> 9 ! lugs ( ! negative plates1 & ! pile w !n be ready = imm]sion 9 ! electrolyte4 ,to bo? ends ( ea* plate-b> sold] b9d+-po/s1 s t ! conductor-wires c be atta*$ at "o end & ! fe$-wires at ! o!r4 ,if a h>d rubb] or glass cell c be _h = ! batt]y s mu* ! bett]2 if n1 a /\t box may be made f p9e1 :ite-wood1 or cypress1 & ?or\ghly coat$ ) asphaltum v>ni% or asphaltick4 ,at an electrical supply-h\se y c pur*ase "s 8,p & ,b0 comp\nd1 :i* is acid & wat] pro(4 ,?is is excell5t = ! inside coat+ z well z = ! outside ( ! box4 ,! box %\ld be made ( wood n less ?an ?ree-qu>t]s ( an in* ?ick1 & ! sides1 ends1 & bottom %\ld be 9 "o piece1 free f knots1 sappy places1 or cracks4 ,brass screws %\ld be us$ to hold ! bo>ds toge!r1 & be=e ! jo9ts are made ! butt-ends ( wood & ! sides1 aga9/ :i* !y imp+e1 mu/ be ?or\ghly coat$ ) ! asphaltum or comp\nd4 ,put toge!r ! f\r sides fir/ & !n make ! bottom fa/1 plac+ ! screws two in*es ap>t & c\nt]s9k+ ! wood1 s t ! screw-heads w lie flu%1 z %[n 9 ,fig4 #af4 ,! box %\ld be l>ge en\gh to all[ ab\t "o in* ( space all ar\nd ! pile1 & deep en\gh = ! solution to cov] ! plates & two in*es ( space above x to ! top edge ( ! cell4 ,! complete /orage-batt]y w !n appe> z %[n 9 ,fig4 #ag4 ,! electrolyte is compos$ ( sulphuric acid & wat] 9 ! proportion ( "o ounce ( acid to f\r ( wat]1 mak+ a five-"p solution4 ,?is %\ld be mix$ 9 an e>!n or glass j>1 & ! acid p\r$ sl[ly into ! wat]1 ! latt] be+ /irr$ :ile ! acid is add$4 ,:5 ! solution cools 7= add+ acid to wat] creates heat71 add ab\t two ounces ( bic>bonate ( soda1 & mix ! solution ?or\ghly4 ,:5 ! pile is 9 place )9 ! box 7hav+ fir/ remov$ ! /r+ :i* b\nd ! plates toge!r7 p\r ! electrolyte sl[ly into ! cell1 tak+ c>e t none ( x spatt]s1 = x w eat clo?+ or any?+ else t x t\*es4 ,be=e plac+ ! pile1 or electrolyte1 9 ! box1 x %\ld be ?or\ghly te/$ = leaks by all[+ wat] to /& 9 x = sev]al days4 ,inde$1 y %\ld be v g5]\s ) ! asphaltum1 or comp\nd1 :5 coat+ ! angles & po9ts inside ! box2 = if ! acid solution gets at ! screws x w corrode !m & ! box w soon leak & fall ap>t4 ,z a precaution aga9/ ! acid work+ ov] ! top ( ! box1 ! upp] edge1 = an in* or two1 %\ld be coat$ ) p>aff9e ov] ! asphaltum or acid-pro( coat+4 ,a cell con/ruct$ 9 ?is way %\ld accumulate ab\t two volts & "o hundr$ amp]e-h\rs1 & w run a "o-sixte5? horse-p[] motor4 ,! exp5se ( mak+ ^! plates is ab\t tw5ty-five c5ts ea*1 &1 includ+ ! cell & coat+ mat]ials1 ea* /orage-batt]y w co/ approximately two doll>s4 ,! la/+ qualities ( ! batt]y dep5d on ! use or abuse x is put to2 b ) ord9>y c>e x %\ld la/ f ?ree to five ye>s4 ,:5 ! batt]y ceases to accumulate prop]ly ! pile %\ld be remov$1 &1 aft] wa%+ x ?or\ghly1 ! b>s %\ld be cut away & new positive plates made & in/all$4 ,! positive plates are ! ones t det]iorate & ne$ replac+2 ! negatives are almo/ ev]la/+1 & ) prop] usage w live = fifte5 or tw5ty ye>s4 ,directly ! electrolyte is 9 ! cell1 connect ! poles ( y\r prim>y cells s z to beg9 ! accumulation ( curr5t4 ,nev] exhau/ ! *>ge ( electricity f y\r /orage-cell1 & nev] leave x un*>g$ :5 ! electrolyte is 91 or ! plates w be ru9$4 ,a batt]y consi/+ ( f five to tw5ty blue/one cells w be ! be/ ) :i* to *>ge ?is accumulator2 & if m ?an "o cell is desir$1 any numb] ( !m c be made & c\pl$ up 9 s]ies4 ,take c>e1 :5 connect+ ! wires f ! prim>y cells1 to see t ! positive wire is connect$ ) ! positive plates & ! negative ) ! lead b> jo9+ ! yell[ plates4 ,if by accid5t y %\ld make a misconnection1 bubbles w rise f ! electrolyte4 ,?is is n "r1 s rev]se ! wires & ! accumulation ( curr5t w !n take place )\t agitation 9 ! cell4 ,dry-cells & ,batt]ies ,dry-cells are ext5sively us$ n[adays1 s9ce _! cleanl9ess1 high effici5cy1 & l[ int]nal resi/ance make !m pref]able to ! ,leclan* & o!r op5-circuit batt]ies = bells1 annunciators1 & o!r light "w4 ,9 ! dry-cell1 ! electrolyte1 in/ead ( be+ a liquid1 is a gelat9\s or semi-solid mass1 :i* w n run nor slop ov]4 ,:5 ! capp+ ( pit* or t> is 9 place1 ! cell may be plac$ 9 any position1 ) full assurance t ! electrolyte w n become displac$ nor run out4 ,dry-cells may be made ( almo/ any size = conv5i5ce ( h&l+1 b ^? commonly us$ v>y f "o to f\r in*es 9 diamet]1 & f f\r to fifte5 in*es high4 ,= bells & g5]al electric "w1 a cell two in*es & a half 9 diamet] & sev5 in*es high w be f\nd a conv5i5t size to make & h&le4 ,! compon5t p>ts ( a dry-cell are ! cell itself 7:i* is made ( z9c & acts z ! positive pole71 ! c>bon1 ! electrolyte or active excitant elem5t1 & ! pit* or t> cap to hold ! electrolyte & c>bon 9 place4 ,f a t9smi? obta9 "s pieces ( %eet z9c1 & roll !m into cyl9drical =m z %[n 9 ,fig4 #ah ,a4 ,! %eets %\ld measure sev5 by eight in*es1 & :5 =m$ ! edges are to be lapp$ & sold]$4 ,illu/ration3 ,,fig4 #ah ,f a small] piece ( z9c cut r\nd bottoms1 fit !m 9 ! cyl9d]s & sold] securely 9 place1 tak+ c>e to close up all seams or jo9ts to prev5t ! escape ( ! electrolyte4 ,f a supply-h\se obta9 batt]y-c>bons1 "o in* & a half wide by half or ?ree-eigh?s ( an in* ?ick & eight in*es long4 ,^! %\ld be provid$ ) a ?umb-screw or small bolt & nut at ! top s z to make wire connections ) ! c>bon4 ,a /rip ( z9c %\ld be sold]$ to ! outside upp] edge ( ! z9c cup to :i* wire atta*m5ts may be made ) ?umb-screws or small bolts & nuts4 ,:5 ! p>ts are ready to assemble1 make a wood5 m\ld or =m a trifle l>g] ?an ! c>bon4 ,?is is int5d$ to act z a tempor>y plung]1 & is ins]t$1 at fir/1 9 place ( ! c>bon plate4 ,?is wood5 plung] %\ld be smoo?1 & giv5 a coat ( %ellac to prev5t x f absorb+ any moi/ure4 ,ins]t ! plung] 9 ! z9c cup & support x s t x w be at lea/ half an in* above ! bottom & c5tr$ at ! middle ( ! cup4 ,! electrolyte is !n plac$ 9 ! cup1 &1 :5 x has set a little1 ! wood5 plung] is remov$ & ! c>bon ins]t$ 9 its place4 ,! electrolyte is compos$ z foll[s3 ,ammonium *loride #a "p ,z9c *loride #a "p ,pla/] ( ,p>is #c p>ts ,fl\r "p ,wat] #b p>ts ,mix ^! toge!r & place ! comp\nd )9 ! z9c cups1 s t ! mass settles d[n & packs closely ab\t ! plung]4 ,! space left unfill$ ab\t ! c>bon %\ld be fill$ ) a mixture compos$ z foll[s3 ,ammonium *loride #a "p ,z9c *loride #a "p ,manganese b9oxide #a "p ,granulat$ c>bon #a "p ,fl\r #a "p ,pla/] ( ,p>is #c p>ts ,wat] #b p>ts ,^! proportions may be measur$ 9 a t9 cup1 a table-spoon1 or any o!r small receptacle4 ,note t ! measurem5t by p>ts is always by bulk & n by weight4 ,d n fill ! z9c cup to ! top1 b leave an in* ( space1 s t half an in* ( seal+ mat]ial may be add$4 ,see t ! inside top edge ( ! z9c cup is clean2 !n melt "s t> or pit* & p\r x ov] ! top ( ! electrolyte1 s t x b9ds ! z9c cup & c>bon into a solid =m4 ,drive an awl d[n ?r\gh ! capp+ mat]ial :5 x is ne>ly dry1 & leave ! holes op5 = ! escapem5t ( gases4 ,give ! out] surface ( ! z9c cells a coat ( asphaltum v>ni%1 & wrap sev]al ?icknesses ( heavy pap] ab\t !m to prev5t contact & %ort-circuit+4 ,protect ! bottoms 9 a simil> mann]1 & z a result y w h a cell t w appe> z %[n 9 ,fig4 #ah ,b4 ,a batt]y ( cells p[]ful en\gh = any light "w c be made by connect+ ! cells 9 s]ies1 ea* hav+ an electro-motive =ce ( "o & a half volts1 ) an int]nal resi/ance ( less ?an "o-?ird ( an ohm4 ,*apt] ,,iii ,,pu%-,,buttons ,,& ,,swit*es ,pu%-buttons ,pu%-buttons & swit*es are a necessity 9 e home :]e electric bells1 lights1 or fans are us$1 = ) !m connections are made or brok54 ,! telegraph-key & ! commutators on a motor & dynamo are only improv$ =ms ( ! pu%-button1 & ?is simple little device is really an indisp5sable "p ( any electrical equipm5t4 ,! simple/ =m ( pu%-button is a b5t piece ( t9 or ?9 %eet-metal screw$ fa/ to a small block ( wood1 z %[n 9 ,fig4 #a4 ,"u ! screw-head "o end ( a wire is caught1 & ! o!r wire end is secur$ by a wa%] & a screw driv5 into ! block directly "u ! project+ end ( ! /rip ( metal4 ,by press+ a f+] on ! t9 x is br\ght into contact ) ! screw-head "u x1 & ! circuit is clos$2 on releas+ x1 ! t9 flies up & ! circuit is op5$ aga94 ,an enclos$ pu%-button is %[n 9 ,fig4 #b4 ,x is made ( ! cov] or body ( a wood5 box1 a spool-end1 & sev]al o!r small p>ts4 ,a r\nd piece ( ?9 wood is cut to fit inside ! box & s =m ! base = ! button4 ,on ?is ! spr+ /rip is atta*$ ) screws1 & ! wire ends are made fa/1 z %[n 9 ,fig4 #c4 ,! wires are c>ri$ ?r\gh ! bottom ( ! base & along grooves to ! edge1 & !nce to _! f9al de/9ation4 ,! end ( a spool is cut (f & glu$ to ! top ( ! box1 z %[n 9 ,fig4 #b1 & a hole is made 9 ! box to correspond 9 size ) t 9 ! spool4 ,?r\gh ?is ap]ture ! button 7cut f a wood5 d[el or %ap$ out ) a knife7 passes1 s t ! end projects ab\t a qu>t] ( an in* beyond ! spool4 ,to prev5t ! button f fall+ out1 a small /eel nail %\ld be driv5 across ! inn] end1 or a wa%] may be tack$ to ! end ( ! /ick1 z %[n 9 ,fig4 #d4 ,illu/ration3 ,,fig4 #a ,illu/ration3 ,,fig4 #b ,illu/ration3 ,,fig4 #c ,illu/ration3 ,,fig4 #d ,! button is m\nt$ by screw+ ! base fa/ to ! door or w9d[ cas+1 x be+ und]/ood t ! wires h be5 fir/ arrang$ 9 place4 ,! button is !n set 9 ! hole & ! cap is plac$ ov] ! base1 cov]+ x completely4 ,by means ( small screws1 pass$ ?r\gh ! rim ( ! box & into ! edge ( ! base1 ! cap is held 9 place4 ,a coat ( pa9t or v>ni% w f9i% ! wood-"w nicely1 & ?is home-made button %\ld !n answ] e requirem5t4 ,swit*es & ,cut-outs ,9 electrical equipm5t & exp]im5tal "w1 swit*es & cut-outs w be f\nd necess>y1 p>ticul>ly s = telegraph & telephone l9es4 ,c>e %\ld be tak5 to con/ruct !m 9 a /rong & durable fa%ion1 = !y w probably be subject$ to consid]able we> & te>4 ,a simple swit* 7,fig4 #e7 is made f a base-block ( wood ?ree in*es long1 two wide1 & half an in* 9 ?ickness1 toge!r ) "s small metal p>ts4 ,x has b "o contact-po9t1 & t is ! brass-head$ tack 7,t 9 ,fig4 #e7 driv5 ?r\gh ! b9d+-po/1 ! latt] be+ a small plate ( brass1 copp]1 or ev5 t9 screw$ to ! base-block4 ,! end ( a wire is caught "u ! screw-head be=e x is driv5 d[n4 ,a simil> b9d+-po/ is arrang$ at ! l[] side ( ! block1 & ! movable arm is atta*$ to x ) a screw4 ,betwe5 ! arm & ! po/-plate !re %\ld be a small copp] wa%]1 to make x "w m easily4 ,! arm is cut f a ?9 piece ( h>d %eet brass or copp] 7t9 or z9c w also answ] v well71 & at ! loose end ! half ( a small spool is atta*$1 ) a brass screw & wa%]1 to s]ve z a h&le4 ,! end ( ! screw t passes ?r\gh a hole 9 ! arm is rivet$ to ! "u side to hold x securely 9 place4 ,?is arrangem5t is %[n 9 ,fig4 #f4 ,illu/ration3 ,,fig4 #e ,illu/ration3 ,,fig4 #f ,illu/ration3 ,,fig4 #g ,illu/ration3 ,,fig4 #h ,illu/ration3 ,,fig4 #i ,! "u edges ( ! arm may be slightly bevell$ ) a file1 s t x w slip up easily on ! oval head ( ! brass tack4 ,! draw+ %[s an op5 swit*2 :5 ! circuit is clos$ ! arm re/s on ! tack-head4 ,by means ( small screws ?is swit*-bo>d may be fa/5$ to a table or to any "p ( ! wood-"w 9 a h\se4 ,9 ,fig4 #g a complex swit* is %[n4 ,?is is ! pr9ciple ( ! %unt-box swit*1 ( ! resi/ance-coil1 & also ( ! commutators ( a motor4 ,a motorman's controll] on a trolley-c> is a good example ( ! %unt1 &1 ) x & ! resi/ance-coils1 ! c> c be />t$1 /opp$1 or run at any spe$1 accord+ to ! curr5t t is admitt$ to ! motor4 ,! complex swit* is made 9 ! same mann] z describ$ = ! s+le swit*1 except t any numb] ( b9d+-po/s may be employ$1 arrang$ on a radial plan1 s t ! end ( ! arm w re/ on any tack-head at w4 ,bells 9 v>i\s p>ts ( ! h\se may be rung by ?is swit*1 or x may be c\pl$ ) a s]ies ( resi/ance-coils to control any am\nt ( curr5t4 ,! simple cut-out 7,fig4 #h7 is con/ruct$ 9 ! same mann] z ! simple swit*1 except t !re are two po9ts ( contact in/ead ( "o4 ,?is is ! pr9ciple ( ! telephone & telegraph in/rum5t wir+1 s t a bell or s\nd] may be rung f a di/ance4 ,! arm is !n ?r[n ov] & ! bell cut out1 all[+ ! 8phone0 or key to be br\ght into use4 ,9 lift+ ! transmitt] f ! hook on a telephone1 a cut-out is op]at$ & ! bell circuit is ?r[n out ( action4 ,x is 9 op]ation aga9 directly ! transmitt] is return$ to ! hook4 ,! swit* cut-out 7,fig4 #i7 is inactive :5 ! arm is 9 ! position %[n 9 ! illu/ration2 b :5 x is ?r[n ov] 7z %[n by ! dott$ l9e7 x connects ! poles at opposite ends ( ! bo>d4 ,x may be ?r[n ov] 9 bo? directions1 & is a useful swit* = _m purposes4 ,= /rong curr5ts ! lev]-swit*1 t re/s on a brass tack-head1 w n be suitable1 z ! swit*-b> mu/ be held firmly 9 place to make a p]fect connection4 ,/rong curr5ts ?r[ weak swit*es op51 caus+ an op5 or brok5 circuit4 ,a s+le pole-swit*1 to c>ry a curr5t up to "o hundr$ & tw5ty-five volts & tw5ty-five amp]es1 is %[n 9 ,fig4 #aj4 ,?is consi/s ( a base-block1 a b> :i* is atta*$ to ! v]tical e>s ( a b9d+-po/1 & a clut* t w hold ! b> :5 x is press$ d[n betwe5 ! e>s4 ,! base-block %\ld be made f "s non-conduct+ mat]ial1 su* z soap/one1 m>ble1 or slate4 ,if a piece ( soap/one c be procur$1 t w be j ! ?+1 s9ce x is easily work$ into ! prop] %ape & size4 ,soap/one may be saw$ & smoo!d ) a file2 x is easily bor$ into ) a gimlet-bit1 & x is "o ( ! be/ non-conduct+ sub/ances4 ,! base = ?is swit* is six in*es long1 two in*es wide1 & z ?ick z ! soap/one happ5s to be--say ?ree-qu>t]s ( an in*4 ,! top edge may be bevell$ = ! sake ( appe>ance or left squ>e4 ,two pieces ( heavy %eet copp] or brass are to be cut z %[n at ,a 9 ,fig4 #aa4 ,! e>s are half an in* wide1 & ! total height ( ! /rip is two in*es & a half1 :ile ! "p ) two holes 9 x side by side is "o in* & a qu>t] long1 includ+ ! half-in* wid? ( ! v]tical /rip4 ,) r\nd & flat-nos$ pli]s b5d ! long e>s into %ape1 s z to =m a keep] = ! b> :i* is !n to be rivet$ 9 place4 ,omit ! holes at ! ends ( ! long e>s 9 ! o!r plate2 !n b5d x into %ape to =m a clut* t w hold ! b> :5 x is press$ d[n betwe5 ! e>s4 ,^! b9d+-po/s %\ld be made fa/ to ! base-block ) brass ma*9e-screws & nuts1 :i* w fit 9 c\nt]sunk holes 9 ! bottom ( ! soap/one4 ,if h>d-wood is us$ = ! base1 ord9>y brass wood-screws w answ] v well4 ,! connection-b> is cut f metal ! same ?ickness z t employ$ = ! b9d+-po/s & clut*es2 x %\ld be %ap$ s z to appe> z %[n at ,b 9 ,fig4 #aa4 ,a h&le %\ld be driv5 on ! slim end1 & :]e ! l[] edge ent]s betwe5 ! e>s ( ! clut*1 ! corn]s ( ! b> %\ld be r\nd$ ) a file4 ,c\nt]sunk screw-holes are bor$ 9 ! base1 s t x c be made fa/ to ! wood-"w4 ,illu/ration3 ,,fig4 #aj ,illu/ration3 ,,fig4 #aa ,illu/ration3 ,,fig4 #ab ,a d\ble pole-swit* is %[n 9 ,fig4 #ab1 & 9 g5]al con/ruction x is simil> to ! s+le pole-swit* describ$ above4 ,! b9d+ po/s & b>s are cut & b5t f ! patt]ns ,a & ,b 9 ,fig4 #aa2 b 9 ?is case ! long1 slim ends ( ! b>s are omitt$4 ,a %ort turn is made at ! h&le end ( ea* b> & a h>d-wood block is plac$ betwe5 ! b>-ends & held 9 position ) screws driv5 ?r\gh holes made 9 ! b>s & into ! ends ( ! block4 ,a h&le is made fa/ to ! middle ( ! block ) a long & slim wood-screw2 or a /eel-wire nail may be pass$ ?r\gh ! h&le & block1 a burr slipp$ ov] ! end opposite ! head1 & ! small end rivet$ fa/4 ,:5 ! b9d+-po/s 7to :i* ! ends ( ! b>s are atta*$7 are screw$ onto ! base1 be sure & see t ! b>s are p>allel & ! same di/ance ap>t at bo? ends4 ,9 l mann]1 :5 ! cleat b9d+-po/s are made fa/1 see t !y are directly 9 l9e ) ! b>s1 s t ! yoke w drop into ! spaces betwe5 ! e>s )\t hav+ to be pull$ to "o side or ! o!r4 ,?is is a v useful swit* = /rong curr5ts1 & may be plac$ close to a dynamo1 s t ! curr5t 9 bo? wires may be cut out at once4 ,table-jack ,swit*es ,a table-jack swit* is a mo/ conv5i5t piece ( app>atus :]e sev]al l9es ( bells1 al>ms1 or telephone circuits are to be swit*$ on & (f4 ,! s+le table-jack swit*1 %[n 9 ,fig4 #ac1 is made ( a h>d-wood block ?ree-qu>t]s ( an in* ?ick1 five in*es wide1 & sev5 in*es long4 ,x is to be smoo!d & v>ni%$1 or giv5 sev]al coats ( %ellac4 ,at ! f\r corn]s small holes are made to receive slim screws1 & at "o end ( ! block five %ort metal plates are screw$ fa/1 ) ! heads ( ! screws c\nt]sunk1 s t !y w be flu% ) ! top ( ! plates4 ,^! small plates %\ld be half an in* wide & "o in* long1 & may be ( brass1 copp]1 or t94 ,b if !y are ( t9 ! plates are made ( a long] /rip tack$ to ! bo>d & !n b5t ov]1 z %[n at ,a 9 ,fig4 #ad4 ,!y w !re=e =m %ort spr+s1 ! upp] p>ts ( :i* w re/ aga9/ ! long spr+-arms4 ,f spr+ brass or copp] five arms are to be cut & %ap$1 z %[n 9 ,fig4 #ac4 ,holes are made at "o end ( ea*1 & o!rs aga9 two in*es f ^!1 ?r\gh :i* to pass screws4 ,screw-eyes are pass$ ?r\gh copp] wa%]s & ! end holes 9 ! /rips1 & !n screw$ into ! wood plate4 ,^! w act z b9d+-po/s1 :ile ! second l9e ( screws w hold ! plates d[n to ! base4 ,! arms %\ld be b5t1 s t :5 ! screws are driv5 d[n ! l[] edge w press on ! small plates "u !m4 ,! outlet wires are atta*$ to ! b9d+-po/s at ! head ( ! block1 & ! plug 7,a 9 ,fig4 #ac7 is ins]t$ betwe5 ! arm & plate at ! foot1 s t contact & connection are made4 ,?is plug is a small plate ( metal to :i* ! end ( a flexible wire is made fa/4 ,x %\ld be ( copp] or brass1 b = light "w a /rip ( t9 may be b5t ov] ) ! wire caught betwe5 ! plates & a copp] tack pass$ ?r\gh ! sides & rivet$1 z %[n at ,b 9 ,fig4 #ad4 ,a d\ble jack-swit* 7,fig4 #ae7 is made on ! same g5]al plan z ! s+le1 b x has no b9d+-po/s4 ,a block ( ! same size is us$1 & two r[s ( %ort plates are made fa/ at ea* end4 ,! arms are made ) two screw-holes ne> ! middle1 z %[n 9 ,fig4 #ae1 & ?r\gh ^! holes screws are driv5 to hold ! arms d[n to ! base4 ,sev]al plugs are us$ = ea* end1 s t ! 9 & out l9es c be %ift$1 & f "o to f\r l9es us$ at a "t4 ,illu/ration3 ,,fig4 #ac ,,fig4 #ad ,,fig4 #ae ,,fig4 #af ,,table-,,jack ,,swit*es ,a conv5i5t slip-swit* = s+le or d\ble l9e "w is %[n 9 ,fig4 #af4 ,?is consi/s ( a small wood5 base1 on :i* a brass arm & h&le are screw$ fa/ & connect$ ) a b9d+-po/ 7,a 9 ,fig4 #af74 ,a slip-plate is made f a piece ( %eet-brass & b5t s z to =m a pocket into :i* ! arm w fit4 ,?is pocket piece is connect$ ) ! b9d+-po/ ,b4 ,:5 ! swit* is ?r[n out ! circuit is brok51 unless a contact-po9t1 ,c1 is provid$1 f ! "u side ( :i* a wire leads out to a second circuit4 ,:5 ! swit* is 9 place1 z %[n 9 ,fig4 #af1 ! circuit is clos$ ?r\gh ,a & ,b2 b :5 ! arm is ?r[n out ! circuit ?r\gh ,a & ,b is brok5 & t ?r\gh ,a & ,c is clos$4 ,b9d+-po/s & ,connectors ,to make quick connections betwe5 wires & o!r p>ts ( electrical app>atus1 b9d+-po/s are ! mo/ conv5i5t device1 s9ce ! turn ( a screw b9ds or releases a wire in/antly4 ,b9d+-po/s may be made 9 _m =ms1 b ! simple ones t a boy w ne$ c be made f screw-eyes1 burrs1 /ove-bolts1 & nuts1 toge!r ) ?9 /rips ( metal & nails4 ,five simple po/s are %[n 9 ,fig4 #ag4 ,a is made f a screw & two burrs1 ,b f a screw-eye & two burrs1 & ,c f a ?9 plate ( metal & two screws1 ) oval or r\nd heads4 ,?is la/1 h[ev] is m ( a connector ?an a b9d+-po/4 ,! ends ( ! wires to be connect$ %\ld be caught "u ! screw-heads or betwe5 ! burrs be=e ! screws are driv5 d[n4 ,9 ,d a simple arrangem5t ( a /ove-bolt & two nuts is %[n4 ,! "u bolt is screw$ d[n tightly aga9/ ! wood1 & "u ! head a wire is made fa/1 s t ano!r wire may be caught "u ! upp] nut4 ,if a small ?umb-nut c be _h 9 place ( ! pla9 nut1 x w be easi] to b9d ! upp] wire4 ,9 ,fig4 #ag ,e a ?9 /rip ( metal may be fold$ ov]1 & at ! loose ends a hole %\ld be pun*$ ?r\gh :i* a screw-eye w pass4 ,! metal is held to a wood base ) a screw1 "u ! head ( :i* a wire is caught4 ,! second wire end is slipp$ betwe5 ! metal plates1 & a turn ( ! screw-eye w b9d & hold x securely4 ,illu/ration3 ,,fig4 #ag ,illu/ration3 ,,fig4 #ah ,connectors are employ$ to unite ! ends ( wires tempor>ily1 & are made 9 _m =ms4 ,a simple & useful "o is made f a piece ( spiral spr+ fa/5$ to a block ( wood by two /aples1 z %[n at ,fig4 #ah ,a4 ,! ends ( ! wires are press$ d[n into ! coils ( ! spr+ & are held ) suffici5t security = tempor>y use4 ,ano!r connector is made f a block ( wood1 a /rip ( ?9 metal1 & two screw-eyes 7,fig4 #ah ,b74 ,! metal is b5t ar\nd ! ends ( ! block1 & ?r\gh holes made 9 ! ends ( ! /rip screw-eyes are driv5 into ! block4 ,:5 ! ends ( wires are slipp$ "u ! metal1 a turn ( ! eyes w hold !m fa/1 z %[n at ,fig4 #ah ,b4 ,a %ort bolt ?read$ at ea* end & provid$ ) f\r nuts w also act z a connector4 ,! inn] nuts are screw$ on tightly & ! out] ones are loose1 s t :5 wires are plac$ betwe5 !m !y may be tight5$ ) ! f+]s1 z %[n at ,c 9 ,fig4 #ah4 ,^! are a few simple =ms ( connectors2 ! +5i\s boy c devise _m o!rs to suit 8 ne$s & ideas4 ,lightn+-arre/]s & ,fuse-blocks ,all l9es ( expos$ wire t run f out-doors into ! h\se %\ld be provid$ at bo? ends ) lightn+-arre/]s1 p>ticul>ly if !y are telephone or telegraph l9es1 burgl> al>ms1 or mess5g] call-boxes4 ,9 _m in/ances :]e unprotect$ telephone l9es h be5 ! play?+ ( lightn+1 pa9ful accid5ts h happ5$1 & x is only ! "p ( prud5ce to provide aga9/ !m4 ,x is bett] to h an arre/] at bo? ends ( a l9e1 & z ! co/ is insignificant x is h>dly wor? consid]+ z aga9/ its feature ( safety4 ,lightn+-arre/]s may be con/ruct$ 9 _m ways & ( diff]5t mat]ials2 ! ones "h %[n & describ$ are easily made & effici5t4 ,! pr9ciple ( all arre/]s is simply a fuse :i* burns out :5ev] ! wire is c>ry+ a great] am\nt ( curr5t ?an is requir$ = ! prop] work+ ( ! app>atus1 !reby arre/+ ! curr5t & protect+ ! in/rum5ts f de/ruction4 ,induction-coils1 relays1 f9e w9d+s on armatures1 or a magnet helix are quickly de/roy$ if a too p[]ful curr5t is p]mitt$ to pass ?r\gh !m1 & x is !re=e advisable to protect !m4 ,:5 a fuse burns out "u a trolley-c>1 or 9 ! %unt-box ( a motor-c> or eng9e1 x is because a great] am\nt ( curr5t is try+ to pass 9 ?an ! motor w safely /&4 ,:5 a fuse 8bl[s out10 ! app>atus or motor is put out ( commission until ! fuse is replac$1 b ! delicate me*anism & ! f9e wir+ on ! field-magnets or armatures are sav$4 ,! simple/ =m ( s+le pole-fuse is a f9e piece ( lead wire held betwe5 two b9d+-po/s1 z %[n at ,a 9 ,fig4 #ai4 ,! lead wire may be ( any l5g?2 b = small in/rum5ts1 :]e a mod]ate curr5t is employ$ & :]e !re is a possibility ( lightn+ travell+ on ! wire1 ! fuse %\ld be f two to ?ree in*es long4 ,= inside "w1 h[ev]1 :]e x is to be us$ simply z a safety1 ! wire may be %ort] & f9]4 ,to make ! lightn+-arre/] %[n 9 ,fig4 #ai1 cut out a h>d-wood block five in*es long1 an in* wide1 & half an in* ?ick4 ,give ?is sev]al coats ( %ellac2 !n place a piece ( mica1 or asbe/os pap]1 ov] ! top ( ! block1 & make x fa/ ) ?ick %ellac to act z a glue4 ,f small pieces ( copp] or brass cut two plates "o-half by "o in*1 & drill holes 9 !m to take screws & screw-eyes4 ,place copp] burrs "u ! screw-eyes = connectors1 & drive two brass screws half-way d[n 9 ! block ?r\gh ! holes at ! inn] ends ( ! b9d+-po/ plates4 ,see t ^! screws fit snugly 9 ! holes 9 ! plates s t contact is p]fect4 ,if ! holes are too l>ge & ! screws fit loosely1 two copp] burrs w h to be us$ & ! screws driv5 91 s t ! heads b9d ! burrs on ! ends ( ! fuse-wire4 ,f an electrician1 or supply-h\se1 pur*ase a few in*es ( f9e lead fuse-wire--say ,nos4 #bj1 #bb1 or #bd--;& twi/ ! ends ( a l5g? ar\nd ! screws1 z %[n 9 ! draw+4 ,p]fect contact %\ld be _h betwe5 ! lead wire & ! screws2 by way ( precaution1 a bit ( sold] w dispel all d\bt4 ,j t\* ! po9t ) a little sold]+ solution2 !n apply a sold]+-iron hav+ a drop or two ( sold] on ! end4 ,p]fect connection is absolutely necess>y = telephone1 telegraph1 or annunciator "w1 & :]e !re is a lightn+-arre/] & ! l9e is n work+ well1 ! tr\ble may (t5 lie 9 ! poor contact ( lead & brass or copp]1 or possibly 9 us+ wire t is too f9e4 ,lead is a v poor conductor1 & a f9e wire w\ld act z a *eck4 ,= a te/1 fir/ ins]t a piece ( copp] wire to see t ! l9e is work+ prop]ly2 !n use lead wire ( suffici5t size to c>ry ! curr5t z well z ! copp] did4 ,! action ( metals & wire1 z curr5t ret>d]s1 w be expla9$ 9 ! *apt] on resi/ance & resi/ance-coils4 ,= g5]al comm]cial use ! base-blocks ( all lightn+-arre/]s %\ld be made ( porcela91 slate1 or "s ( ! composition non-conductors1 su* z m\ld$ mica1 silex & %ellac1 or fibre4 ,z ^! are n always available1 wood1 ) a cov]+ ( mica1 w answ] e purpose & c be readily adapt$ = use4 ,! app>atus pictur$ 9 ,fig4 #ai is kn[n z a s+le-pole lightn+-arre/]1 & is ! simple/ =m ( ?is k9d ( electrical p>aph]nalia4 ,9 ,fig4 #bj a d\ble-pole arre/] is %[n4 ,?is is con/ruct$ 9 ! same mann] z describ$ = ! s+le "o4 ,! block is five in*es long1 two in*es wide1 & half or five-eigh?s ( an in* ?ick4 ,a c\nt]sunk hole is made 9 ! middle ( all ! lightn+-arre/] blocks ?r\gh :i* a screw c be pass$ to hold ! app>atus fa/ 9 any desir$ location4 ,9 ,fig4 #ba ano!r =m ( fuse is %[n4 ,x is made f a piece ( mica ?ree-qu>t]s ( an in* wide & f\r in*es long1 two pieces ( ?9 %eet-copp]1 & a piece ( lead fuse-wire4 ,! copp] is ?ree-qu>t]s ( an in* wide1 & "o piece ( x is b5t 9 ! =m ( a ,v1 z %[n at ,a 9 ,fig4 #ba4 ,"o end ( ! mica /rip is dropp$ 9 ! ,v1 & ) a pair ( pli]s ! ,v is clos$ up by p9*+ x at ! bottom4 ,to fur!r insure its /ay+ 9 place1 ! top & end1 or op5 edges1 %\ld be sold]$4 ,pun* a small hole ?r\gh ! copp] ends1 at ! inside edge1 slip ! ends ( ! fuse-wire 9 !m1 & t\* ! union ) a drop ( sold] to insure p]fect contact4 ,) %e>s & file cut a ,u f ! side ( "o copp] b& & f ! end ( ! o!r2 ^! w all[ ! copp] ends to pass "u ! heads ( screws1 ?us avoid+ ! necessity ( remov+ ! entire screw f ! block 9 ord] to set ! fuse 9 place4 ,illu/ration3 ,,fig4 #ai ,,fig4 #bj ,,fig4 #ba ,,fig4 #bb ,,fig4 #bc ,,fig4 #bd ,,fig4 #be ,,fig4 #bf ,,lightn+-,,arre/]s ,,& ,,fuse-,,blocks ,! block on :i* ?is fuse is held is %[n 9 ,fig4 #bb1 & is made 9 a simil> mann] to ! "o %[n 9 ,fig4 #ai1 except t ! metal plates are a trifle long] & are b5t up1 z %[n 9 ! draw+4 ,?us ! mica fuse-plate w be elevat$ above ! block4 ,if ! brass or copp] us$ = ! b9d+-po/ plates is too ?9 to /& ! pressure ( ! screws :5 ! fuse ends are screw$ fa/1 put a few burrs on ! screws bel[ ! plates2 !n ! pressure ( ! screws _c b5d d[n ! ext5d+ e>s ( ! plates & make an imp]fect contact4 ,ano!r =m ( fuse-block is %[n 9 ,fig4 #bc4 ,! same sort ( a fuse is employ$ z %[n 9 ,fig4 #ba1 b )\t ! ,u cuts at ! ends4 ,! clut*es are made by b9d+ brass or copp] plates1 z %[n 9 ! draw+2 !y %\ld !n be screw$ fa/ to a base-block five in*es long1 "o in* & a half wide1 & five-eigh?s ( an in* ?ick4 ,! op5+ betwe5 !m %\ld j admit ! copp] ends ( ! fuse1 & pressure %\ld be us$ to =ce ! fuse 9 place s t ! contact w be p]fect4 ,/ill ano!r =m ( fuse is %[n 9 ,fig4 #bd4 ,?is la/ may m prop]ly be call$ a non-sp>k+ fuse1 = ! lead wire is encas$ 9 a glass tube1 & :5 x fuses no sp>ks fly & no small pieces ( melt$ metal c get away f ! inside ( ! tube4 ,! plug is made f a piece ( glass tube half an in* 9 diamet]1 two metal caps1 & a %ort piece ( lead wire4 ,! metal caps are ( ?9 %eet-copp]1 & are caught at ! edges ) sold]4 ,"o end ( ! lead fuse-wire is pass$ ?r\gh a hole 9 ! end ( a cap & sold]$1 z %[n at ,a 9 ,fig4 #bd4 ,! wire is !n pass$ ?r\gh ! tube & ! cap plac$ ov] "o end ( x4 ,?is is repeat$ at ! o!r end & ! wire sold]$ fa/4 ,z a result1 y w h a glass tube ) metal caps held on ! ends ( ! tube1 by means ( ! ?9 lead wire :i* runs ?r\gh ! middle ( ! tube4 ,! base-block to :i* ?is fuse-plug is atta*$ is ( wood "o in* & a half wide1 five or six in*es long1 & five-eigh?s ( an in* ?ick4 ,two metal /raps are made & screw$ fa/ to ! block1 & ! circuit wires are atta*$ "u ! copp] burrs & held d[n by ! screw-eyes4 ,to place or replace a fuse-plug1 unscrew ! eyes & raise ea* /rap slightly1 s t ! copp] cap ends w pass "u !m4 ,a turn or two ( ! eyes w clamp ! plug 9 position & at ! same "t b9d ! circuit wires4 ,a spr+ lightn+-arre/] is %[n 9 ,fig4 #be2 x is simply a modifi$ =m ( t %[n & describ$ 9 ,fig4 #ai4 ,! base-block is five by "o-&-a-qu>t] by five-eigh?s ( an in*1 & is prop]ly protect$ by a %eet ( mica or asbe/os4 ,! two metal plates are cut = ! b9d+-po/s & screw$ 9 place ) screws1 burrs1 & screw-eyes4 ,f spr+-brass wire b5d a hook & slip "o end ( x "u ! screw-head at ! left side ( ! block4 ,f a long] piece ( wire make two or ?ree turns ar\nd a piece ( wood half an in* 9 diamet]2 !n =m a hook at "o end & a turn at ! o!r1 s t x c be made fa/ "u ! screw-head ( ! b9d+-po/4 ,:5 at re/1 ! spr+-hook %\ld /& 9 an upright position1 b :5 sprung & ti$ x occupies ! position %[n 9 ! draw+4 ,! spr+-hook is to be b5t d[n s t ! two hooks are br\ght )9 an in* ( ea* o!r4 ,!y are held 9 ?is position ) a piece ( lead fuse-wire4 ,?is la/ is giv5 a turn ab\t ! hooks & "o or two turns ab\t itself1 close to ea* hook1 to prev5t ! spr+ f te>+ itself away4 ,:5 ! wire is fus$ by a curr5t ! spr+-hook flies up & away f possible contact ) ! %ort hook atta*$ to ! opposite b9d+-po/4 ,?is is ! con/ruction = a s+le-pole-spr+ lightn+-arre/]2 a d\ble "o is made 9 a simil> mann]1 & ! p>ts m\nt$ on a wid] block1 z %[n 9 ,fig4 #bj4 ,= d\btful curr5ts1 :]e !re is no means ( kn[+ h[ /rong !y are1 a comb9$ fuse & s+le-pole swit* is %[n 9 ,fig4 #bf4 ,?is is no?+ m ?an a comb9ation ( ! app>atus %[n 9 ,fig4 #ba1 & ! s+le-pole swit* 7,fig4 #aj74 ,! base block is sev5 in*es long & two in*es wide4 ,or x may be made half an in* wid] if x is to be bevell$ at ! top1 z %[n 9 ! draw+4 ,x %\ld be ?ree-qu>t]s ( an in* ?ick & provid$ ) two c\nt]sunk holes = screws t w hold x 9 place on a l$ge or aga9/ a casem5t4 ,! little angles to hold ! copp]-end$ mica fuse-plate are describ$ = ! app>atus pictur$ 9 ,fig4 #ba4 ,if x is desir$ t "o ( ! ends %\ld be provid$ ) burrs & a screw-eye1 ! little plate ( brass %\ld be an in* long & an in* wide1 ) a half-in*-squ>e piece snipp$ f "o corn]1 z %[n at ,a 9 ,fig4 #bf4 ,x is provid$ ) two holes1 & !n b5t on ! dott$ l9e1 s t ! "p ) ! holes w lie on ! block & ! e> w /& 9 a v]tical position4 ,a rev]se-plate made on ?is patt]n w act z "o side ( ! swit*-b> clut* at ! opposite end ( ! block4 ,= ! metal clut* & keep] at ! middle ( ! block ! metal plate 7be=e x is b5t7 w appe> z %[n at ,b 9 ,fig4 #bf4 ,! long plate ) two holes lies on ! base1 :ile ! fir/ e> 7or ! "o )\t ! hole7 =ms "p ( ! clut* = ! fuse end1 ! e> ) ! hole act+ z "o side ( ! b>-lev] /rap4 ,an opposite plate to ?is =ms ! o!r side ( ! clut* & /rap1 & ! two plates are screw$ side by side1 s t ! fuse-plate w be held securely :5 pu%$ into place4 ,= ! swit*-b> use a piece ( h>d copp] or brass f\r in*es long1 half an in* wide1 & ab\t "o-eigh? ( an in* ?ick1 or ! same ?ickness z ! copp] /raps at ! ends ( ! mica fuse-plate4 ,bore a hole at "o end ( ?is b>1 & ) a copp] rivet atta* x betwe5 ! two upright e>s at ! middle ( ! block4 ,) a file cut away ! two edges at ! o!r end ( ! b> = a di/ance ( an in*1 s t ! b> w h an end z %[n at ,c 9 ,fig4 #bf4 ,drive a small file-h&le on ?is end & give x a coat or two ( %ellac2 !n bevel ! l[] edges ( ! b> ) a file :]e x ent]s betwe5 ! blades ( ! clut*4 ,! circuit wires are made fa/ at bo? ends ( ! block1 & ! curr5t travels ?r\gh ! b9d+-po/s1 ! lead fuse-wire on ! mica plate ,d1 & ! swit*-b>4 ,if ! curr5t is too /rong1 !n :5 ! swit*-b> is pu%$ into ! clut* ! safety-fuse w burn out & save ! app>atus2 or x w arre/ a fla% ( lightn+4 ,*apt] ,,iv ,,magnets ,,& ,,induction-,,coils ,simple & ,horse%oe ,magnets ,e boy has a horse%oe magnet among 8 collection ( useful odds & ends1 & :e!r x is a l>ge or small "o its work+ pr9ciple is ! same4 ,if l>ge en\gh x w lift a jack-knife1 nails1 or solid weights1 su* z a small flat-iron or an iron padlock4 ,a horse%oe magnet is made ( highly temp]$ /eel & magnetiz$ s t "o end is a nor? pole & ! o!r a s\? pole4 ,9 m sci5tific language ^! poles are kn[n z1 respectively1 positive & negative4 ,once magnetiz$ ! in/rum5t reta9s t prop]ty indef9itely1 unless ! p[] is drawn f x by exposure to int5se heat1 & ev5 !n1 by successive heat+ & cool+1 ! magnetism may be p>tially re/or$4 ,an electro-magnet may be made ( any scrap ( s(t iron1 f a piece ( ord9>y telegraph-wire to a gigantic iron %aft4 ,:5 a curr5t ( electricity passes ?r\gh a wire a magnetic 8field0 is produc$ ar\nd ! wire1 & if ! latt] is insulat$ ) a cov]+ & coil$ ab\t a s(t iron object1 su* z a nail1 a bolt1 or a rod1 t object becomes a magnet s long z a curr5t ( electricity is pass+ ?r\gh ! coils ( wire or helix4 ,a coil ( wire 9 ! =m ( a spiral spr+ has a /rong] field ?an a /raight wire c>ry+ ! same curr5t1 = ea* turn or convolution adds its magnetic field to t ( ! o!r turns4 ,a simple =m ( electro-magnet is made by w9d+ sev]al lay]s ( ,no4 #bj insulat$ copp] wire ar\nd a /\t nail or a c>riage-bolt2 by connect+ ! ends to a batt]y ( suffici5t p[]1 "s v heavy objects may be lift$4 ,a s+le magnet1 l ! "o %[n 9 ,fig4 #a1 is made ) a piece ( s(t iron rod six in*es long & half an in* 9 diamet]1 ! ends ( a l>ge spool saw$ (f & work$ on ! rod1 & half a p\nd ( ,no4 #bj insulat$ copp] wire4 ,! spool-ends are arrang$ z %[n 9 ,fig4 #b4 ,an end ( ! wire is pass$ ?r\gh a hole 9 "o flange :5 y beg9 to w9d ! coils1 & :5 f9i%$1 ! o!r end is pass$ ?r\gh a hole at ! out] rim ( ! same flange4 ,?is magnet may be held 9 ! h&s :5 9 use2 or a h&-magnet may be con/ruct$ ( a long] piece ( iron on "o end ( :i* a h&le is driv5 & held 9 place ) a nut & wa%]1 z %[n 9 ,fig4 #c4 ,! wires f ! coil pass ?r\gh holes made 9 ! h&le & come out at ! butt end1 :]e !y may be atta*$ by connectors to ! pole-wires ( a batt]y4 ,to protect ! out] insulat$ coil ( wire f *af+ & a possible %ort-circuit1 x w\ld be well to wrap sev]al ?icknesses ( /\t pap] ar\nd ! coil & glue x fa/2 or a lea!r cov] w answ] z well4 ,illu/ration3 ,,fig4 #a ,,fig4 #b ,,fig4 #c ,,fig4 #d ,,fig4 #e ,,fig4 #f ,,fig4 #g ,,simple ,,& ,,horse%oe ,,magnets ,a m p[]ful magnet may be made f a /\t bolt1 two nuts1 & a wood5 base1 ) ab\t ?ree-qu>t]s ( a p\nd ( ,no4 #ah insulat$ copp] wire to w9d ab\t ! body ( ! bolt4 ,a block ( wood an in* ?ick1 f\r in*es wide1 & six in*es long is provid$ ) a hole at ! middle = ! bolt to pass ?r\gh4 ,a l>g] hole is made at ! "u side ( ! block s t a nut c be easily turn$ 9 x4 ,a ?ree-qu>t]-in* ma*9e-bolt1 ) a squ>e head1 & sev5 in*es long1 is set 9 ! block1 head up1 z %[n 9 ,fig4 #d2 & composition or ?9 wood5 disks or wa%]s are plac$ on ! bolt to hold ! coils ( wire 9 place4 ,! ends ( ! wire pass out ?r\gh ! bottom wa%] & are made fa/ to b9d+-po/s on ! block1 & to ^! latt] ! batt]y-poles are made fa/ :5 ! magnet is 9 use4 ,coils ( wire may be w\nd on an ord9>y spool1 & ! hole 9 ! middle may be fill$ ) l5g?s ( s(t iron wire4 ,:5 a curr5t is pass+ ar\nd ! spool ! wires become highly magnetic1 b lose ! magnetism directly ! curr5t ceases4 ,horse%oe electro-magnets are made by w9d+ coils on ! ends ( ,u-%ap$ pieces ( s(t iron1 b ! w9d+ mu/ be done s t ! curr5t w pass ar\nd !m 9 opposite directions1 o!rwise y w\ld h two negatives in/ead ( a negative & positive4 ,= a small horse%oe magnet a /\t iron /aple may be us$1 b = ! l>g] magnets x w\ld be be/ to h a blacksmi? b5d a piece ( r\nd iron 9 ! desir$ %ape4 ,a p[]ful horse%oe magnet may be made f a piece ( tire-iron b5t z %[n 9 ,fig4 #e ,a2 :5 w\nd ) ,no4 #ah wire x w appe> l ,fig4 #e ,b4 ,a volt or two ( curr5t pass+ ?r\gh ! coils w r5d] ?is magnet p[]ful en\gh to lift sev]al p\nds4 ,= bells1 telegraph-s\nd]s1 & o!r electrical equipm5t requir+ ! horse%oe or d\ble magnet1 sev]al k9ds may be us$1 b ! simple/ is con/ruct$ f two c>riage or ma*9e bolts & a yoke ( s(t iron1 z %[n 9 ,fig4 #f4 ,! yoke is five-eigh?s ( an in* 9 wid?1 two in*es & a half long1 & provid$ ) two ?ree-eigh?s-in* holes1 "o in* & a half ap>t f c5tre to c5tre4 ,two-in* c>riage or ma*9e bolts are us$1 & !y %\ld be ?ree-eigh?s ( an in* 9 diamet]4 ,! nuts are turn$ on ! ?read f> en\gh to admit ! yoke1 & !n ano!r nut is appli$ to hold x 9 place & b9d ! ?ree pieces into "o compact mass4 ,wood5 spool-ends or composition wa%]s are plac$ on ! bolts to hold ! ends ( ! wire coils 9 place1 & ! w9d+ may be done on ea* bolt sep>ately & lock$ to ! yoke aft] ! w9d+ is complet$4 ,d\ble cotton-insulat$ ,no4 #bj or #bb copp] wire %\ld be us$ = ! coils4 ,x is a t$i\s & bo!rsome job to w9d a coil by h&1 & if possible a w9d] %\ld be employ$ = ?is purpose4 ,sev]al v>ieties ( w9d]s are on ! m>ket1 b a simple "o = ord9>y spools may be made f a /ick held 9 an upright piece ( wood ) /aples4 ,?is idea is pictur$ 9 ,fig4 #g1 :]e ! r\nd /ick is %[n cut ) two grooves into :i* ! /aples fit4 ,"o end ( ! /ick is made ) a squ>e %\ld]1 s t a h&le & crank c be fitt$ to x4 ,a few wraps ( wire are tak5 ar\nd ! crank to prev5t x f splitt+1 & x is held to ! r\nd /ick ) a slim /eel nail4 ,! opposite end ( ! r\nd /ick is %av$ (f s t x w fit snugly 9 ! hole ( a spool2 if x %\ld be too small = "s spools1 a few turns ( cord ar\nd ! small end w make x b9d4 ,! block to :i* ! %aft & crank is atta*$ may be held 9 a vise or screw$ to ! edge ( a table4 ,induction-coils ,a simple induction or %ock+ coil may be made ( a two-&-"o-half by five-sixte5?s-in* bolt1 a ?9 wood5 spool1 & two sizes ( insulat$ copp] wire4 ,an induction-coil is a peculi> & wond]ful app>atus2 x figures l>gely 9 electrical exp]im5t+ & is a "p ( e complete equipm5t4 ,a piece ( curta9-pole may be us$ = ! spool4 ,fir/ bore a five-sixte5?s-in* hole ?r\gh ! wood to receive ! bolt2 !n 9 a la! turn x d[n into a spool ) less ?an "o-eigh? ( an in* ( wood ab\t ! hole & ) flanges ab\t "o-eigh? ( an in* 9 ?ickness4 ,smoo? ! spool ) s&-pap]1 :ile x is /ill 9 ! la!1 & give x a ?9 coat or two ( %ellac4 ,slip ! spool on ! w9d] 7,fig4 #g7 & w9d on ?ree lay]s ( ,no4 #bd cotton-insulat$ copp] wire1 tak+ c>e to wrap ! coils ev5ly & close4 ,br+ six in*es ( ! ends out at ei!r end ( ! spool ?r\gh small holes pi]c$ 9 ! flanges2 !n wrap sev]al ?icknesses ( br[n pap] ar\nd ! coil4 ,a curr5t pass+ ar\nd ?is ?ree-lay] coil w magnetize ! bolt4 ,?is is ! prim>y coil & ! "o ?r\gh :i* ! batt]y curr5t w pass4 ,a second>y coil is n[ made ov] ! prim>y "o ) elev5 or ?irte5 lay]s ( ,no4 #cj insulat$ copp] wire4 ,x w take "s "t to c>efully put on ^! lay]s1 & :5 do+ s m>k d[n ea* lay] s z to keep an accurate c\nt1 = !re mu/ be ! "r numb] ( lay]s to make ! coil act prop]ly4 ,no4 #cj wire is q f9e1 & if ! lay]s are n incl9$ to lie smoo?1 make a wrap or two ( br[n pap] betwe5 ea* ?ree lay]s4 ,br+ six in*es ( ea* end ( ! wire out f ! flanges ( ! spool1 & to protect ! out] coil wrap pap] ab\t ! coils & atta* x fa/ ) ?read or p>aff9e4 ,slip ! bolt ?r\gh ! hole & screw ! nut on ! ?read$ end4 ,cut out a wood5 block f\r in*es long1 ?ree in*es wide1 & ?ree-qu>t]s ( an in* ?ick1 & ) two ?9 metal /raps & screws atta* ! coil to ! middle ( ! block1 z %[n 9 ,fig4 #h4 ,make f\r b9d+-po/s & screw !m fa/ at ! corn]s1 & to ,a & ,b ( ,fig4 #h atta* ! ends ( ! heavy wire f ! prim>y coil1 & to ,c & ,d ( ,fig4 #h ! ends ( ! f9e wire f ! second>y coils4 ,! induction-coil is n[ ready = any use to :i* x may be put1 & by m\nt+ x on ! block ) ! delicate wire ends atta*$ to ! b9d+-po/s1 x is 9 less dang] ( damage ?an if ! wire ends 7 left loose = r\gh-&-ready connections4 ,9 ord] to get a %ock f ?is coil x w be necess>y to h a pair ( h&les & a curr5t int]rupt]4 ,! h&les may be made f two pieces ( t9 roll$ into ! =m ( cyl9d]s to :i* wires are sold]$4 ,or1 bett] yet1 use pieces ( ?9 brass tub+ an in* 9 diamet]4 ,! buzz] %[n 9 ,fig4 #i may be employ$ = a curr5t int]rupt]1 & a bi*romate batt]y w furni% ! curr5t4 ,9 ord] to make ! connections1 ! wires f ! h&les are atta*$ to ! b9d+-po/s ,c & ,d 9 ,fig4 #h--t is1 to ! wires ( ! second>y coil4 ,"o spool ( ! batt]y is connect$ ) ,a ( ,fig4 #h & ! o!r ) ,a ( ,fig4 #i4 ,a wire connects ,c ( ,fig4 #i ) ,b ( ,fig4 #h1 & ! circuit is clos$4 ,! buzz] n[ beg9s to vibrate1 & any "o hold+ ! h&les w receive a %ock ! int5sity ( :i* dep5ds on ! /r5g? ( ! batt]ies4 ,a swit* %\ld be introduc$ some:]e 9 ! circuit1 s t x may be op5$ or clos$ at w2 a good place = x is betwe5 a batt]y-pole & ! b9d+-po/ ,a 9 ,fig4 #h4 ,if ! %ock is too int5se x may be weak5$ by draw+ ! c>bon & z9c poles p>tly out ( ! bi*romate solution2 or a regulator may be made ( a l>ge glass tube & a glass pres]v+-j> fill$ ) wat]4 ,if ! tube _c be _h1 an ,arg& gas-burn] *imney w answ] z well4 ,sold] a wire to ! edge ( a small t9 or copp] disk1 z %[n 9 ,fig4 #aj1 on :i* ! *imney re/s at ! bottom ( ! j>1 & ano!r wire to a t9 box-cov] ) "s small holes pun*$ 9 its top1 ?is latt] be+ susp5d$ )9 ! *imney4 ,?is second wire is pass$ out ?r\gh a cork at ! top ( ! *imney made ( a disk ( c>dbo>d & a piece ( wood4 ,"o wire is connect$ ) ,a ( ,fig4 #h & ! o!r ) a batt]y-pole4 ,?is app>atus acts ! same z a resi/ance-coil1 & by rais+ or l[]+ ! box-cov] ! curr5t is increas$ or dim9i%$4 ,! clos] ! cov] comes to ! disk ! /rong] ! curr5t1 z !re is less wat] = ! electricity to pass ?r\gh & !re=e less resi/ance2 :ile if ! cov] t\*es ! disk ! curr5t fl[s z freely z if !re 7 no regulator & ! wires ran directly to ! cell4 ,an app>atus compris+ a coil1 an int]rupt]1 or armature1 & a swit* may be set on "o block1 & ! arrangem5t ( ! sev]al p>ts is cle>ly %[n 9 ! draw+ ( ! complete galvano-f>adic app>atus 7,fig4 #aa74 ,! block %\ld be six in*es long1 f\r in*es wide1 & sev5-eigh?s ( an in* 9 ?ickness4 ,illu/ration3 ,,fig4 #h ,illu/ration3 ,,fig4 #i ,illu/ration3 ,,fig4 #aj ,illu/ration3 ,,fig4 #aa ,illu/ration3 ,,fig4 #ab ,! coil is made z describ$ = ,fig4 #h1 ! spool be+ ?ree in*es long & "o in* & a qu>t] 9 diamet]4 ,a c>riage-bolt ?ree in*es & a half long & five-sixte5?s ( an in* 9 diamet]1 ) a bevell$ head1 is made fa/ 9 ! spool1 & ?is coil is /rapp$ to ! block ) two metal b&s & screws4 ,two b9d+-po/s 7,a & ,b ( ,fig4 #aa7 are arrang$ at ! upp] corn]s1 & to ^! ! ends ( ! second>y coil wires are atta*$4 ,two m b9d+-po/s 7,c & ,d ( ,fig4 #aa7 are arrang$ at ! l[] side & provid$ ) a swit* to op5 & close ! circuit4 ,"o ( ! prim>y coil wires is made fa/ to ,c1 & ! o!r "o to a block :i* conta9s ! set-screw t be>s aga9/ ! vibrat+ armature4 ,its arrangem5t & ! wire connection is expla9$ 9 ,fig4 #i ,b4 ,an armature ( ?9 brass or t9 is made & atta*$ to a block 7,e 9 ,fig4 #aa74 ,at ! loose end t is opposite ! bolt-head sev]al wraps ( t9 are made & sold]$ fa/1 or a small block ( s(t iron may be rivet$ to ! armature4 ,x mu/ be ( iron or t91 h[ev]1 s z to be attract$ by ! electro-magnetiz$ bolt-head4 ,?is arrangem5t may be se5 9 ,fig4 #ab4 ,atta* a ?ick piece ( pap] ov] ! bolt-head1 s t ! lug at ! end ( ! armature w n adh]e to x ?r\gh residual magnetism4 ,9 regul> galvano-f>adic ma*9es ! curr5t regulator is =m$ ( a holl[ cyl9d] :i* is drawn f ! core ( ! coil2 b 9 ?is simple ma*9e ! wat]-j> regulator may be connect$ betwe5 a pole ( ! batt]y & ! b9d+-po/s 7,d or ,e ( ,fig4 #aa74 ,! wires ( ! h&les are atta*$ to po/s 7,a & ,b ( ,fig4 #aa71 & :5 all ! wires are 9 place & ! curr5t turn$ on by means ( ! swit*1 ! vibrator beg9s to "w & ! %ock+-curr5t is felt ?r\gh ! h&les4 ,by means ( ! regulat+-screw t be>s on ! armature1 ! numb] ( vibrations may be increas$ or dim9i%$1 b = f>adic purposes ! vibrations %\ld be z quick z possible4 ,mu* amusem5t may be _h ) ?is app>atus1 & a l>ge numb] ( p may be giv5 a %ock by gett+ !m to jo9 h&s :5 /&+ or sitt+ 9 a circle4 ,an ,electric ,buzz] ,?is piece ( app>atus is1 9 !ory1 no?+ m ?an ! electric bell1 & might prop]ly be includ$ 9 ,*apt] ,v41 on ,annunciators & ,bells4 ,b s9ce x is ! logical developm5t ( pr9ciples j laid d[n1 x has be5 ?\ght be/ to give x its pres5t position4 ,! electric buzz] is con/ruct$ on ! pr9ciple ( ! telegraph-s\nd]1 b in/ead ( mak+ a s+le click or /roke ! curr5t is made to act on ! armature & keep up a cont9u\s motion s long z ! electricity passes ?r\gh ! helix ( ! cores1 ! armature1 & ! contact-po9ts ( ! app>atus4 ,a buzz] has ! same movem5t z an electric bell ) ! r++ app>atus remov$4 ,= (fices1 h\ses1 & quiet calls x is (t5 pref]r$ to ! l\d r++ ( a bell4 ,! electric buzz] %[n 9 ,fig4 #ac is easy to make2 x is op]at$ by ! aid ( a cell & a pu%-button4 ,cut a base-block ?ree in*es & a half wide1 five in*es long1 & ?ree-qu>t]s ( an in* ?ick1 & m\nt a horse%oe magnet made ( bolts & a yoke & coils ab\t at ! middle ( x1 z %[n 9 ,fig4 #i4 ,! magnet is held to ! base by a flat wood5 cleat & a screw pass$ d[n ?r\gh a hole 9 ! cleat & into ! base1 betwe5 ! coils4 ,an armature ( s(t iron1 two in*es long & half an in* wide1 is rivet$ to a piece ( spr+-brass1 z %[n 9 ,fig4 #ad ,a1 & ! end is b5t s t x w fit ar\nd ! corn] ( a block to :i* x is held fa/ ) two screws4 ,?is armature is m\nt$ s t !re is a space "o-sixte5? ( an in* wide betwe5 x & ! bolt-heads1 z y c see 9 ,fig4 #i4 ,! brass is b5t out slightly & runs p>allel ) ! armature = "o in* & a qu>t]4 ,aga9/ ?is ! end ( ! screw m\nt$ 9 block ,b ,fig4 #i re/s4 ,illu/ration3 ,,fig4 #ac ,illu/ration3 ,,fig4 #ad ,! block ,b is a small piece ( h>d-wood screw$ fa/ to ! side ( ! base to hold ! set-screw & also ! wire t comes f ! outside ( ! upp] coil4 ,a small hole is made 9 ! edge ( ! block & ! wire pass$ 91 s t ! end re/s 9 ! screw-hole z %[n by ! dott$ l9e4 ,:5 ! screw is plac$ 9 ! hole & turn$1 x comes into contact ) ! wire & makes a connection4 ,?is block & its atta*m5t is %[n 9 ,fig4 #ad ,b4 ,on ! base1 ne> ! armature-block1 a b9d+-po/ is made fa/1 & ! curr5t1 pass+ 9 ?r\gh ! wire ,a 9 ,fig4 #i1 goes ?r\gh ! coils & ar\nd to ! screw ,b1 !n ?r\gh ! armature to ! block1 & out ?r\gh ! wire ,c4 ,9 its circuit ! bolts are magnetiz$1 & !y draw ! armature1 b ! in/ant !y d s ! loose spr+-brass end is pull$ away f ! screw-po9t ,b & ! circuit is brok51 ! bolts cease to be magnetiz$1 & ! armature flies back "u ! influ5ce ( ! spr+-brass neck at ,d4 ,! loose brass end1 on t\*+ ! screw-po9t1 conducts ! curr5t ?r\gh ! coils aga91 ) a cont9ual vibrat+ action1 s long z ! electric curr5t is pass+ 9 at ,a & out at ,c4 ,! great] ! volume ( curr5t ! great] ! numb] ( vibrations1 & to prop]ly regulate ! contact ! set-screw ,b mu/ be adju/$ at ! "r po9t4 ,pa/e pieces ( heavy pap] ov] ! heads ( ! bolts to ov]come residual magnetism4 ,a s+le electric bell is made ! same z a buzz]1 b cont9u+ on f ! end ( ! armature a wire or rod is m\nt$ ) a ball at ! end :i* /rikes ! bell z ! curr5t causes ! armature to vibrate4 ,! bell-block may be made long]1 & a bell f an old clock or a bicycle %\ld be m\nt$ at ! prop] place on a wood5 d[el driv5 into ! base4 ,a screw passes ?r\gh ! hole at ! middle ( ! bell & into ! top ( ! d[el4 ,! ball at ! end ( ! rod may be made ( brass ) a hole 9 x1 & a drop ( sold] w hold x 9 place4 ,or x may be made ( wire w\nd r\nd ! end & sold]$ into a compact mass4 ,a ,l>ge ,induction-coil ,z has be5 said1 ! induction-coil is "o ( ! my/]i\s ph5om5a ( electrical sci5ce4 ,:ile its practical value is kn[n & recogniz$ 9 all bran*es ( voltaic electricity = use 9 trans=m+ curr5ts1 its actual work+s h nev] be5 cle>ly expla9$4 ,! con/ruction ( a small induction-coil 0 expla9$ 9 ! description ( a %ock] or m$ical batt]y4 ,= bigg] equipm5ts1 wireless telegraphy & o!r uses1 a l>ge induction-coil w be necess>y1 & ! foll[+ illu/rations & descriptions %\ld enable ! "y electrician to con/ruct an app>atus t w be bo? simple & effici5t 9 its work+4 ,= ! tube 79 :i* to w9d ! prim>y coils7 obta9 a piece ( r$ fibre-tub+1 "o in* inside diamet] & n m ?an "o-eigh? ( an in* 9 ?ickness4 ,! l5g? %\ld be t5 in*es4 ,if fibre _c be _h use a pa/e-bo>d tube4 ,f :ite-wood1 half an in* 9 ?ickness1 saw two blocks f\r in*es squ>e & 9 ! c5tre ( ea* cut a hole s t ! tube w pass ?r\gh x & fit snugly4 ,"s %ellac & a few slim brass escut*eon p9s w hold ! blocks 9 place1 z %[n at ,fig4 #ae4 ,! wood blocks & fibre or pap] tube %\ld be treat$ to sev]al successive coats ( %ellac to give !m a good f9i% & prev5t ! absorption ( moi/ure4 ,f\r b9d+-po/s1 ) wood screw-ends1 are to be made fa/ at ! top edges ( ! end-blocks1 z %[n at ,fig4 #ae4 ,holes bor$ 9 ! blocks ne> ! foot ( ! b9d+-po/s w admit ! ends ( ! coil-wires s t contact c be made4 ,! ends ( ! conductor-wires %\ld !n be plac$ 9 ! holes 9 ! b9d+-po/s & held 9 place ) ! ?umb-screws4 ,illu/ration3 ,,fig4 #ae ,illu/ration3 ,,fig4 #af ,! prim>y coil is made by w9d+ f\r lay]s ( ,no4 #bj insulat$ copp] wire on ! tube & betwe5 ! end-blocks1 z %[n at ,fig4 #af4 ,ea* lay] mu/ be w\nd ev5ly1 & ! /r&s %\ld lie close to ea* o!r4 ,:5 ! fir/ lay] is on give x a coat ( %ellac2 !n wrap a piece ( ?9 pap] ab\t x & give t also a coat ( %ellac4 ,:5 ! second lay] is on repeat ! op]ation ( %ellack+ & pap]-coat+1 & cont9ue ) ! ?ird lay]4 ,:5 ! f\r? lay] is on give ! coil a d\ble wrap ( pap] & two or ?ree coats ( %ellac to ?or\ghly insulate x & keep out all moi/ure4 ,! w9d+ may be done by h&1 b x is mu* easi] to d x on a w9d] or reel1 :i* c be op]at$ to revolve ! core1 ! wire unw9d+ f its orig9al spool z x is w\nd on ! tube4 ,a conv5i5t w9d] may be made on a base-bo>d :i* c be clamp$ to a table or b5*4 ,! bo>d is twelve in*es long1 eight or t5 in*es wide1 & sev5-eigh?s ( an in* ?ick4 ,two uprights1 ?ree in*es wide1 t5 in*es long1 & ?ree-qu>t]s ( an in* ?ick1 are screw$ & glu$ to ! ends ( ! base-bo>d4 ,a not* is cut 9 ! top ( ! end-bo>ds1 into :i* ! sp9dle or %aft c re/2 & at ! top ( ! end-pieces two small plates ( wood or metal are screw$ d[n to hold ! sp9dle 9 place :5 ! tube & ends are be+ revolv$4 ,a small hole1 bor$ 9 ea* upright end two in*es above ! top ( ! base-bo>d1 w admit a rod on :i* a spool ( wire c revolve1 z %[n at ,fig4 #ag4 ,two plugs ( wood1 %ap$ l corks1 are made to fit 9 ! ends ( ! fibre-tube4 ,a hole is bor$ ?r\gh ea* "o s t a wire or rod sp9dle w pass ?r\gh !m & fit tightly4 ,"o end ( ! rod is b5t & provid$ ) a small wood5 h&le1 by means ( :i* ! core may be revolv$4 ,?is w9d+-rack makes x easy to h&le ! core-tube :ile putt+ on ! lay]s ( wire1 & x holds ! tube securely :ile ! wraps ( pap] & %ellac are appli$4 ,! second>y coil is laid ov] ! prim>y1 & %\ld be ( ,nos4 #cj to #cf insulat$ copp] wire4 ,! f9] ! wire ! high] ! resi/ance & ! long] ! sp>k1 b no?+ heavi] ?an ,no4 #cj %\ld be us$4 ,beg9 by mak+ "o end ( ! wire fa/ to a b9d+-po/2 !n turn ! core-tube ) "o h&1 hold+ ! wire 9 ! o!r4 ,take c>e n to b9d ! wire nor /ret* x1 b w9d x on smoo?ly & ev5ly1 l ! coils ( ?read on a new spool ( cotton or silk4 ,be v c>eful to avoid k9ks1 breaks1 or un9sulat$ places 9 ! wire4 ,%\ld ! wire become brok51 give ! coil a coat ( %ellac to b9d ! w\nd /r&s2 !n make a f9e twi/$ po9t & cov] x ) ! silk or cotton cov]+1 ) a coat ( %ellac to hold x 9 place1 & proce$ ) ! w9d+4 ,betwe5 ea* lay] ( wire place a ?9 %eet ( pap] & coat x ) p>aff9e1 or %ellac1 to make a p]fect insulation2 !n proce$ ) ! next lay]4 ,) a batt]y & small bell te/ ! wire lay]s occasionally to see t ev]y?+ is all "r1 & t !re are no breaks or %ort circuits4 ,?is is v necess>y to avoid mak+ mi/akes1 &1 consid]+ ! "t & c>e sp5t 9 w9d+ ! coils1 x w\ld be a great disappo9tm5t if ! coil 7 defective4 ,illu/ration3 ,,fig4 #ag ,illu/ration3 ,,fig4 #ah ,ab\t "o p\nd & a half ( wire %\ld con/itute ! second>y coil1 &1 if possible1 x is be/ to h x 9 "o cont9u\s /r&1 )\t splices4 ,ov] ! la/ coil1 aft] ! w9d+ is complet$1 sev]al ?icknesses ( pap] %\ld be laid & well coat$ ) %ellac betwe5 ea* wrap4 ,?is is a protector to insure ! f9e wire /r&s f damage4 ,to improve ! appe>ance ( ! coil a wrap ( ?9 black or color$ lea!r may be glu$ fa/1 ) ! seam or po9t at ! "u side4 ,! ends ( ! wires =m+ ! prim>y coil %\ld be made fa/ to ! b9d+-po/s at "o end1 :ile ^? ( ! second>y coil %\ld be atta*$ to ! po/s at ! o!r end4 ,= ! core1 obta9 "s s(t iron wire1 ab\t ,no4 #ah1 & cut a numb] ( l5g?s4 ,/raight5 ^! %ort wires & fill ! tube ) !m1 pack+ x closely1 s t ! wires w rema9 9 place "u a mutual pressure4 ,x is bett] to make a core ( a numb] ( rods or wires r ?an to h x ( "o solid piece ( s(t iron4 ,n[1 f h>d-wood1 cut a base ?ree-qu>t]s ( an in* ?ick1 five or six in*es wide1 & twelve in*es long4 ,atta* ! coil to ! base by means ( screws pass$ up ?r\gh ! bo>d & into ! l[] edges ( ! end-blocks4 ,! wood is to be /a9$ & giv5 sev]al successive coats ( %ellac4 ,n[ connect ! wires ( a batt]y to ! b9d+-po/s 9 contact ) ! prim>y coil1 & atta* two sep>ate wires to ! second>y coil b9d+-po/s4 ,br+ ^! ends ne> to ea* o!r1 & a sp>k w leap across f "o end to ! o!r1 its size or 8fatness0 dep5d+ on ! /r5g? ( ! batt]y4 ,! complet$ app>atus is %[n at ,fig4 #ah4 ,9 produc+ a long sp>k a cond5s] is an important factor2 x is us$ 9 s]ies ) an induction-coil4 ,!re are sev]al =ms ( cond5s]s1 b p]haps ! simple/ & mo/ effici5t is ! ,fizeau cond5s]1 :i* is made up ( lay]s ( t9-foil ) p>aff9$ pap] z sep>ators4 ,f a flori/'s supply-h\se pur*ase "o hundr$ & fifty %eets ( t9-foil sev5 by n9e in*es1 or %eets t w cut to t size )\t wa/e2 also t5 or twelve extra %eets = /rips4 ,at a pap] supply-h\se obta9 "s cle>1 ?91 t\gh pap] ab\t ! ?ickness ( good writ+-pap]4 ,be c>eful to reject any %eets t are p]=at$ or h any f9e holes 9 !m4 ,! %eets %\ld be eight by t5 in*es1 or half an in* l>g] all ar\nd ?an ^? ( ! t9-foil4 ,! pap] mu/ be ?or\ghly soak$ 9 hot p>aff9e to make x moi/ure-pro( & a p]fect non-conductor4 ,?is is done by plac+ ab\t two hundr$ %eets on ! bottom ( a clean t9 tray1 or photographic develop+-di% ( porcela94 ,don't use glass or rubb]4 ,aft] plac+ "s lumps ( p>aff9e on ! pap]1 put ! tray 9 an ov5 s z to dissolve ! p>aff9e & ?or\ghly soak ! pap]4 ,op5 ! ov5 door &1 ) a p91 raise up ! %eets "o at a "t1 & draw !m out ( ! liquid p>aff9e4 ,z soon z x comes 9 contact ) cool air ! p>aff9e solidifies & ! %eet ( pap] becomes /iff5$4 ,select ea* %eet ) c>e1 s t ^? employ$ = ! cond5s] are free f holes or imp]fect places4 ,f p9e or :ite-wood1 a qu>t] ( an in* 9 ?ickness1 cut two bo>ds1 eight by t5 in*es1 & give !m sev]al good coats ( %ellac4 ,to build up ! cond5s]1 lay "o bo>d on a table & on x place two %eets ( p>aff9$ pap]4 ,on ?is lay a %eet ( t9-foil1 arrang+ x s t half an in* ( pap] w be visible ar\nd ! m>g94 ,f ! odd %eets ( t9-foil cut "s /rips1 "o in* 9 wid? & ?ree in*es long4 ,place "o ( ^! /rips at ! left end ( ! fir/ %eet ( foil1 z %[n at ,fig4 #ai4 ,ov] ?is lay a %eet ( ! p>aff9$ pap]1 !n ano!r %eet ( ! foil4 ,n[ on ?is second %eet ( foil lay ! %ort /rip to ! "r end1 & s proce$ until all ! foil & pap] is 9 place1 arrang+ ea* alt]nate %ort /rip at ! opposite end4 ,c>e mu/ be tak5 to obs]ve ?is ord] if ! cond5s] is to be ( any use4 ,illu/ration3 ,,fig4 #ai ,illu/ration3 ,,fig4 #bj ,:5 ! la/ piece ( foil is laid on1 ) its %ort /rip above x1 add two or ?ree ?icknesses ( pap]1 & !n ! o!r bo>d4 ,) f\r screw-clamps1 "o at ea* corn]1 press toge!r ! mass ( foil1 pap]1 & bo>ds z closely z possible1 !n b9d ! bo>ds ab\t ) adhesive tape1 or /\t tw9e1 & release ! clamps4 ,atta* all ! project+ ends ( foil at "o side by means ( a b9d+-po/1 & ^? at ! o!r end ) ano!r b9d+-po/4 ,! complete cond5s] w !n appe> z %[n 9 ,fig4 #bj4 ,:5 9 op]ation "o wire lead+ f ! second>y coil %\ld be connect$ ) a b9d+-po/ ( ! cond5s]1 s t x is 9 s]ies4 ,! object ( ! cond5s] is to increase ! effici5cy ( induction1 & x %\ld be made 9 proportion to ! size ( ! induction-coil ) :i* x is to be employ$4 ,circuit-,int]rupt]s ,:5 an induction-coil is to be employ$ z a %ock] 7& !re is no vibrat+ armature arrang$ 9 connection ) ! core71 a circuit-int]rupt] mu/ be employ$ to get ! effect ( ! pulsations1 z giv5 out by ! second>y coil :5 a curr5t is pass+ ?r\gh ! prim>y4 ,!re are v>i\s =ms ( circuit-break]s t may be made = ?is purpose1 b = really effici5t s]vice ! type %[n 9 ,fig4 #ba is p]haps ! be/ t c be devis$4 ,?is int]rupt] consi/s ( a metal cog-:eel ) saw-tee?1 a p9ion or axle1 & a h&le4 ,also a base-block1 ) uprights to support x1 & a piece ( spr+-brass wire1 arrang$ s z to be> aga9/ ! :eel4 ,:5 ! :eel is revolv$ ! spr+-wire w be driv5 out by ea* too?2 & :5 releas$ x flies back to ! :eel1 /rik+ ! bevell$ edge ( a too? at ea* trip4 ,two b9d+-po/s1 arrang$ on ! block1 w provide means ( connect+ 9-&-out wires4 ,) a coat or two ( %ellac on ! wood-"w & black asphaltum v>ni% on all surfaces ( ! metal t are n us$ = contact1 ?is circuit-int]rupt] w be ready = any use 9 connection ) an induction-coil4 ,! base-block is ( p9e1 :ite-wood1 or cypress1 sev5-eigh?s ( an in* ?ick1 ?ree in*es wide1 & five in*es long4 ,! uprights1 :i* support ! :eel1 are half an in* ?ick & "o in* wide4 ,! :eel is ?ree in*es 9 diamet] & is made ( brass "o-sixte5? ( an in* ?ick4 ,! design ( ! :eel %\ld be laid out ) a compass & m>k$ ) lead-p5cil or a %>p-po9t$ awl1 :i* w leave a m>k cle> en\gh to be se5 :5 saw+ & fil+ ! tee? & op5 places4 ,illu/ration3 ,,fig4 #ba ,illu/ration3 ,,fig4 #bb ,a true plan is %[n at ,fig4 #ba ,a4 ,?r\gh ! middle ( ! :eel a small hole is bor$ to receive ! axle ( brass :i* is to be sold]$ 9 place4 ,:5 ! :eel is set up1 a metal crank & wood5 h&le %\ld be sold]$ fa/ to "o end ( ! axle4 ,a piece ( spr+-brass wire is fa/5$ to ! block1 ) a /aple1 & ! l[] end b5t s t ! screw 9 "o b9d+-po/ w hold x 9 place4 ,! upp] end ( ! wire is b5t 9 ! =m ( an ,l4 ,f ! o!r b9d+-po/1 ?r\gh ! block & up "o support1 a wire is pass$1 ! end ( :i* comes into contact ) ! axle4 ,! curr5t1 pass+ 9 ?r\gh "o b9d+-po/1 is c>ri$ ?r\gh ?is wire to ! axle1 !n to ! :eel1 & s on out ?r\gh ! spr+-wire & rema9+ b9d+-po/4 ,:5 9 action ! circuit is con/antly be+ brok51 z ! spr+-wire jumps f ! end ( "o too? back to ! face ( ! next too?4 ,! pulsations are increas$ or dim9i%$ by ! fa/ or sl[ spe$ ( ! :eel1 z regulat$ by ! h& motion4 ,! /r5g? ( ! curr5t is regulat$ by ! =ce ( ! batt]y & %\ld be controll$ by a wat] resi/ance1 z describ$ = ! m$ical batt]y1 or %ock+-coil4 ,! int]rupt]1 %[n 9 ,fig4 #bb1 is built up on a block six in*es squ>e & sev5-eigh?s ( an in* ?ick4 ,a circle is cut f %eet-lead & laid on ! face ( ! block1 ?r\gh :i* p9s1 or /eel-wire nails1 are driv54 ,! lead circle is five in*es 9 diamet] & half an in* 9 wid?1 mak+ ! inside diamet] f\r in*es4 ,! p9s or nails are driv5 a qu>t] ( an in* ap>t1 & %\ld be prop]ly & accurately sep>at$1 s t an ev5 make-&-break w be ! result4 ,x is n necess>y to bore holes 9 ! lead1 b ! p9s or nails %\ld be driv5 cle> ?r\gh x1 s t p]fect contact c be _h by ! metal p>ts com+ toge!r4 ,o!rwise ! app>atus w\ld be useless4 ,ov] ! circle ( p9s a brass bridge is erect$1 s t ! cross-/rips w cle> ! heads ( ! p9s4 ,a hole is bor$ at ! middle ( ! bridge s t ! revolv+ axle w pass ?r\gh x4 ,! axle is made f a piece ( /\t wire1 or light rod1 & ne> ! foot ( x1 & ab\t half an in* above ! base-bo>d1 a disk ( metal is sold]$ fa/4 ,a piece ( spr+-brass wire is atta*$ to ?is disk1 s t :5 ! axle is turn$ ! end ( ! wire trips f p9 to p91 ?us mak+ & break+ ! circuit4 ,! upp] "p ( ! axle is b5t & provid$ ) a small wood5 or porcela9 knob4 ,"o wire f ! second>y coil is caught "u a screw t holds "o end ( ! brass bridge to ! base2 & ! o!r to a screw1 :i* may be plac$ at "o corn] ( ! block1 & f :i* a %ort wire leads to ! lead r+4 ,b9d+-po/s may be arrang$ to s]ve ! same purpose1 &1 ( c\rse1 !y are mu* bett] ?an ! screws1 because !y c be easily op]at$ by ! f+]s & d n require a screw-driv] e "t ! int]rupt] is plac$ 9 s]ies ) an induction-coil4 ,an int]rupt] on ?is same ord] may be made f a /raight /rip ( lead ) ! p9s driv5 ?r\gh ! middle ( x4 ,"o wire f ! second>y coil is made fa/ to ! lead plate1 & ! end ( ! o!r wire is pass$ along ! p9s1 ?us mak+ & break+ ! circuit 9 a primitive mann]4 ,*apt] ,v ,,annunciators ,,& ,,bells ,a ,drum ,s\nd] ,a unique electric s\nd] t is sure to attract att5tion is 9 ! %ape ( an electric-bell app>atus1 ) a drum s\nd] 9 place ( a bell1 or knock]less buzz]4 ,fig4 #a4 ,! outfit is m\nt$ on a block f\r in*es & a half wide & sev5 in*es long4 ,! cores & yoke are made z describ$ = ! electric buzz] 7*apt] iv47 & are w\nd ) ,no4 #bb cotton-insulat$ wire4 ,! magnet is !n /rapp$ fa/ to ! block by means ( a h>d-wood plate hav+ a screw pass$ d[n ?r\gh x2 & betwe5 ! coils & into ! block an armature is made & m\nt$ on a metal plate1 :i* 9 turn is screw$ to ! block4 ,ano!r block1 ) a contact-po9t1 is arrang$ to int]rupt ! armature1 & ! s]ies is connect$ z %[n 9 ! draw+ ,fig4 #a4 ,! end ( ! wire project+ above ! armature is provid$ ) a h>d-wood knock] :i* op]ates ^u ! head ( ! drum4 ,! drum is made f a small t9 c1 hav+ "o or two small holes pun*$ 9 ! bottom4 ,ov] ! top a ?9 membrane1 su* z a bladd] or a piece ( %eep-sk9 or cat-sk91 is drawn & la%$ fa/ ) sev]al wraps ( wire1 hav+ ! ends twi/$ toge!r securely4 ,! membrane mu/ be wet :5 drawn ov] ! c end1 & great c>e %\ld be tak5 to get x tight & ev54 ,!n1 :5 x dries1 x w /ret* & draw1 l a drumhead1 & hold its ela/ic1 resonant surface s long z x does n become moi/5$ or wet4 ,?is drum is arrang$ 9 ! prop] position & la%$ fa/ ) wires pass$ ov] ! box & d[n ?r\gh holes 9 ! block2 :]e1 aft] sev]al turns1 ! ends may be securely twi/$ toge!r4 ,9 place ( ! drum a small wood5 box may be la%$ fa/ ) its op5 end aga9/ ! block1 s z to =m a holl[ enclosure4 ,! raps ( ! knock] aga9/ its sides w give =? a resonant xylophone tone4 ,an ,annunciator ,a simple annunciator may be made f a core1 a helix1 & "s brass /rips4 ,a s(t iron core1 made ( a piece ( ?ree-eigh?-in* r\nd iron & ?read$ at "o end1 is conv]t$ into a magnet by hav+ a spool & wire coil arrang$ to enclose x4 ,?is 9 turn is screw$ into a /rip ( brass bor$ & ?read$ to receive x4 ,fig4 #b4 ,?is brass /rip is %ap$ z %[n at ,fig4 #c ,a1 & ! e>s are b5t to s]ve _! sev]al purposes4 ,! l[e/ e>s are turn$ out & ! l[] "p ( ! plate is b5t =w>d s z to =m ! h+e on :i* ! drop-b> turns4 ,! drop-b> is only a /rip ( metal turn$ up at "o end1 on :i* a num]al or lett] c be atta*$2 :ile at ! o!r ! metal %\ld be b5t ov] s z to =m a core into :i* a p9 or wire may be pass$ & ! ext5d+ ends b5t d[n1 aft] be+ caught ?r\gh ! holes 9 ! e>s4 ,above ! magnet ! /rip is b5t =w>d & ! top or end e>s b5t up1 s z to =m ! h+e on :i* ! armature sw+s4 ,holes are made 9 ! long e>s1 ?r\gh :i* screws pass to hold ! annunciator fa/ to ! box or wood-"w4 ,! armature is made f a /rip ( brass & is %ap$ l ,b 9 ,fig4 #c4 ,! two e>s at ! top are b5t d[n & fit )9 ^? at ! top ( ! fir/ /rip4 ,a screw or wire pass$ ?r\gh ! holes 9 ! e>s w complete ! h+e4 ,! /rip is b5t d[n s z to fall 9 front ( ! magnet1 & to its inn] side a button or disk ( %eet-iron is rivet$ fa/1 s z to =m an attraction-plate to be drawn aga9/ ! magnet :5 ! curr5t is pass+ ar\nd x4 ,! l[] "p ( ! armature is b5t 9 hook fa%ion s z to hold up ! drop-b>4 ,a slot is cut 9 ! drop-b> ?r\gh :i* ! hook$ end w project4 ,a %ort spr+ is arrang$ at ! top ( ! annunciator s z to keep ! b> & ! hook 9 place :5 n 9 action4 ,! curr5t pass+ ar\nd ! s(t iron core magnetizes x & draws ! iron button on ! armature t[>ds x4 ,?is action imm$iately releases ! hook f "u ! edge ( ! metal at ! =w>d end ( ! slot1 & ! b> drops1 br++ ! figure d[n & into pla9 sight4 ,x is necess>y1 ( c\rse1 to m\nt ?is annunciator s t ! b> w n drop d[n too f>4 ,?is may be done by hav+ a plat=m or wire run along "u a s]ies ( ! drops1 s t !y w re/ on x4 ,illu/ration3 ,,fig4 #a ,,fig4 #b ,,fig4 #c ,,fig4 #d ,,fig4 #e ,,fig4 #f ,,annunciators ,,& ,,bells ,a ,d\ble ,electric ,bell ,= l\d r++1 & to get ! b5efit ( bo? ! =w>d & backw>d /roke ( ! knock]1 a d\ble bell1 simil> to ! "o %[n 9 ,fig4 #d1 may be con/ruct$ ^u ! g5]al pr9ciple ( ! s+le-/roke buzz] already describ$ 7*apt] iv474 ,two s(t iron cores are made1 z describ$ = ! o!r bells1 b in/ead ( be+ yok$ toge!r ) iron1 s t ! ?ree p>ts w =m a horse%oe magnet1 ! yoke is ( brass or copp]4 ,ea* core w !n be an indep5d5t magnet4 ,! spools are w\nd ) ,no4 #bb insulat$ wire & ! ends left free1 s t ! coils are n connect$ toge!r4 ,if ! draw+ is exam9$ closely y w see t ! armature sw+s on a pivot at ! base ( ! knock]-b>4 ,:5 ! bell is n 9 action ! knock] might re/ naturally aga9/ "o bell or ! o!r2 or x might /& 9 ! c5tre & n t\* a contact-po9t1 7 x n = ! small spr+ :i* draws x to ! left4 ,directly ! curr5t is run ?r\gh ! coils x alt]nately magnetizes fir/ "o & !n ! o!r4 ,?is action is due to ! mak+ & break+ ( ! circuit by ! spr+ on ! armature4 ,x fir/ comes into contact ) "o po9t1 & !n is drawn away f x to come into contact ) ! o!r4 ,fig4 #d %[s ! knock]-b> at re/ betwe5 bo? bells & ! armature unattract$ by ei!r magnet4 ,?is position is purposely giv5 s z to indicate ! balance ( ! armature & ! spaces betwe5 x & ! cores & also ! contact-po9ts above x4 ,! small1 light wire spr+ %[n 9 ! draw+ draws ! knock] to "o side2 !re=e1 :5 at re/1 "o circuit is clos$4 ,o!rwise ! bell w\ld n act :5 ! curr5t is run ?r\gh ! p>ts--9 fact1 ! curr5t c\ld n run ?r\gh at all1 if "o or ! o!r contact 7 n made4 ,! magnets are held fa/ to a base ) a long screw & a small plate ( wood laid across !m z %[n 9 ,fig4 #d4 ,! armature is a piece ( s(t iron "o-eigh? ( an in* ?ick1 half an in* wide1 & ?ree in*es long4 ,?is has a spr+-brass piece atta*$ to x z %[n at ,a ,a 9 ,fig4 #e4 ,small holes are bor$ ?r\gh ! /rip & ! iron1 & escut*eon p9s are pass$ ?r\gh & rivet$4 ,a small hole is made d[n ?r\gh ! middle ( ! iron plate & a p9 is driv5 into x1 s t a qu>t] ( an in* projects at bo? sides4 ,ano!r hole is made ?r\gh ! side ( ! plate = ! knock]-b>4 ,!n ! armature is set 9 place s t !re is a space ( "o-eigh? ( an in* betwe5 x & ! magnet ends4 ,! armature is held 9 place at ! top by a b5t metal /rip 7,b ,b 9 ,fig4 #e74 ,?is is screw$ fa/ to ! base & ! bottom is c\nt]sunk into ! wood4 ,two contact-po9ts 7,c ,c 9 ,fig4 #e7 are arrang$ s t :5 a magnet draws ! armature d[n x br+s ! opposite end ( ! armature spr+ into contact ) a po9t4 ,! wir+ is at ! "u side ( ! base & is %[n 9 ,fig4 #f4 ,! curr5t ent]s b9d+-po/ ,a1 & passes ar\nd coil & magnet ,no4 #a by ent]+ at ,b & leav+ at ,c2 f !nce to ,d1 ent]+ ! armature spr+ at ,e1 :5 ! small spr+ has drawn ! knock]-b> ov] to ! left4 ,! curr5t passes along ! armature & out at ,f2 !n along to b9d+-po/ ,g1 & s on ar\nd ?r\gh batt]y ,k & pu%-button ,l1 ?us complet+ ! circuit4 ,directly t ?is is done ! magnet draws ! spr+ end ( ! armature away f contact-po9t ,d & up aga9/ contact-po9t ,j1 s t ! circuit is brok5 ?r\gh coil ,no4 #a & is s5t ?r\gh coil ,no4 #b4 ,?is imm$iately magnetizes core ,no4 #b & draws ! armature d[n to x1 break+ its contact ) ,j & re-e/abli%+ x ) ,d4 ,! rapid alt]nate mak+ & break+ ( ! circuit1 & ! rapid & /rong motion ( ! armature 9 its seesaw action1 causes ! knock] to rap ! bells s\ndly ea* "t x travels f "r to left & back aga94 ,two bells ( simil> size1 or two drums or wood5 boxes1 may be employ$ = ?is d\ble /rik]1 & ! m curr5t t is run ?r\gh ! coils ! m p[] & a correspond+ increase ( noise4 ,an ,electric ,horn ,"o ( ! mo/ useful pieces ( app>atus :]e a l\d noise is requir$ 7su* z 9 a motor-boat or an automobile7 is ! electric horn4 ,x is a re>rang$ pr9ciple ( ! telephone1 = in/ead ( s\nd ent]+ or /rik+ aga9/ ! membrane or tympanum to be transmitt$ else:]e1 ! di/urbance takes place )9 ! horn & ! s\nd is emitt$4 ,ev]ybody has be5 close to a telephone :5 o!rs h be5 us+ x1 & has he>d noises1 rasp+ s\nds1 & ev5 ! voice ( ! speak] at ! o!r end ( ! l9e4 ,if a cornet 7 play$ at ! o!r end ( ! l9e x c\ld be di/9ctly he>d ?r\gh ! receiv] by _m p]sons 9 ! room1 s9ce its vibrations are l\d en\gh to set up a =cible succession ( s\nd-waves4 ,! same pr9ciple op]ates 9 ! electric horn1 b in/ead ( be+ agitat$ at a long di/ance x is done )9 ! enclosure1 & a v mu* l\d] vibration is consequ5tly produc$4 ,x is q z easy to make an electric horn z to con/ruct a bell1 b c>e mu/ be ex]cis$ to h ! p>ts fit accurately & ! wir+ prop]ly done4 ,if ! draw+s are /udi$ & ! description closely foll[$1 !re is no reason :y a horn _c be made t w dem& any "o's att5tion f "s di/ance away4 ,! complete horn is %[n 9 ! illu/ration ,fig4 #g1 & z x is made ( wood x is easily atta*$ ) screws to a boat or a motor-c>4 ,f :ite-wood1 half an in* ?ick1 cut two blocks ?ree in*es & a qu>t] squ>e4 ,9 "o ( !m 7! re> "o7 bore a hole at ! c5tre1 ( su* size t a piece ( ?ree-eigh?-in* gas-pipe c be screw$ into x4 ,9 ! o!r "o make a hole two in*es 9 diamet]1 s t ! cov] ( a small t9 c w fit into x4 ,outside ?is hole1 & on "o side ( ! block1 cut ! wood away & d[n = "o-eigh? ( an in*1 =m+ a rabbet1 z %[n at ,a 9 ,fig4 #g4 ,?is w be ! back ( ! front block4 ,illu/ration3 ,,fig4 #g ,,an ,,electric ,,horn ,h a gas or /eam fitt] cut a piece ( two-in* iron pipe "o in* & ?ree-qu>t]s long4 ,?is w measure a trifle ov] two in*es & a qu>t]1 outside diamet]1 & w =m ! cyl9d] or cov] = ! me*anism4 ,! piece ( pipe %\ld fit snugly 9 ! front bo>d1 & at ! re> "o ! wood %\ld be cut away s z to let x 9 an eigh? ( an in*1 z %[n 9 ! sectional plan ( ,fig4 #g4 ,obta9 a piece ( ?ree-eigh?-in* gas-pipe1 ?read$ at "o end4 ,cut x ) a hack-saw1 & file ! blunt end s t x w measure "o in* & sev5-eigh?s long1 z %[n at ,c 9 ,fig4 #g4 ,?is is to be screw$ into ! front ( ! re> block s t x w project "o in* & a half4 ,make a spool to fit ! pipe1 z %[n at ,b 9 ,fig4 #g1 or use two wood5 button-m\lds atta*$ to ! pipe ) %ellac or glue4 ,betwe5 !m w9d on ! coils ( ,no4 #bb wire to =m ! helix4 ,cut a hole 9 ! t9-c cov]1 z %[n at ,d 9 ,fig4 #g1 & h a t9smi? sold] a small funnel to x 7= ! horn1 or bell1 z x is call$71 cutt+ away ! l[] "p ( ! funnel s t ! hole 9 x w correspond 9 size ) t 9 ! c cov]4 ,?is jo9t c be made at home by fitt+ ! funnel 9 ! hole & !n turn+ back ! edge1 z %[n 9 ! sectional draw+ at ,e 9 ,fig4 #g4 ,!n1 ) a _s-lamp1 "s sold]+ solution1 & sold]1 make a good jo9t4 ,small holes are to be made at ! corn]s ( ! blocks1 ?r\gh :i* /ove-bolts two in*es & a half long w fit to b9d ! front1 back1 & cyl9d] toge!r4 ,select a good1 clean1 & flat piece ( t9 & cut a disk two in*es & a qu>t] 9 diamet]1 & ?r\gh ! middle make a small hole4 ,cut two pieces ( iron ab\t ! size & ?ickness ( a c5t1 & bore a small hole ?r\gh ! c5tre ( ea*4 ,obta9 a piece ( /\t brass wire1 or ?9 rod1 & file "o end ( x z %[n at ,g 9 ,fig4 #g1 s t ! small end w fit 9 ! holes made 9 ! iron buttons4 ,place "o button on ei!r side ( ! t9 disk1 & pass ! wire ?r\gh2 !n clamp x 9 a vise & rivet ! top ( ! rod s t y w h a disk ) a button at ea* side ( ! c5tre & all atta*$ firmly to a brass rod1 z %[n at ,f 9 ,fig4 #g4 ,! total l5g? ( ?is rod %\ld be two in*es & a half1 & ! l[] end is to be ?read$ & provid$ ) two small brass nuts4 ,a piece ( spr+-brass ?ree-eigh?s or half an in* wide is made fa/ to a small block at ! back ( ! horn1 z %[n at ,h 9 ,fig4 #g1 & at its opposite end a contact-piece ( metal1 b5t at an angle1 is screw$ fa/4 ,ar\nd ! back ( ! back block a wood5 frame is atta*$ to protect ! re> me*anism ( ! horn4 ,! p>ts are n[ ready to assemble4 ,fir/ see t ! metal angle contact-po9t is 9 place ) ! long brass /rip re/+ on x1 & t ?is 9 turn is prop]ly fa/5$ to ! block on ! side opposite ! contact-po9t1 z %[n at ,h 9 ,fig4 #g4 ,!re %\ld be a small hole ?r\gh ! middle ( ! brass /rip directly 9 l9e ) ! middle ( ! hole 9 ! gas-pipe4 ,place ?is back-bo>d d[n on ! table s t x w lie 9 a position z indicat$ 9 ! sectional plan ( ,fig4 #g4 ,! gas-pipe is !n to be screw$ onto ! plate4 ,ov] ?is ! spool ) its lay]s ( wire is to be slipp$ & made fa/1 & ! cyl9d] ( iron is !n plac$ 9 position4 ,ov] ?is ! disk ,f is laid1 s t ! brass rod ext5ds d[n ?r\gh ! pipe & brass /rip2 !n ! nut is screw$ on to hold x 9 place4 ,next comes ! front block1 ) its horn or bell1 & ! entire mass is lock$ toge!r by means ( ! f\r bolts at ! corn]s4 ,! wir+ is simple4 ,"o inlet be+ ?r\gh block ,i1 ! curr5t passes ?r\gh /rip ,j to contact-po9t ,k2 !n ?r\gh ! coil & out at wire ,l4 ,! inlet & outlet wires are connect$ to a batt]y & to a pu%-button or swit*1 s t ! horn c be op]at$4 ,! prop] adju/m5t ( ?is horn dep5ds on ! nuts at ! foot ( ! brass rod4 ,!y mu/ be screw$ on tight en\gh to draw ! /rip ,j s t x re/s on ! contact-po9t ,k4 ,! curr5t1 pass+ 9 at ,i1 ?r\gh ,j1 ,k1 ! coil1 & out at ,l1 magnetizes ! piece ( pipe & draws ! iron buttons or disks atta*$ to ! t9 disk4 ,b s soon z x does s x breaks ! contact betwe5 ,j & ,k1 & ! buttons fly back into place1 hav+ be5 drawn !re by ! rigidity ( ! t9 disk to :i* !y are atta*$4 ,aga9 ! curr5t is clos$ & ! magnet draws ! iron buttons4 ,! brass rod moves b a v slight di/ance up & d[n--en\gh1 h[ev]1 to make & break ! contact betwe5 ,j & ,k4 ,z a result ( ?is rapid movem5t & ! consequ5t snapp+ ( ! t9 disk1 a l\d noise is emitt$ ?r\gh ! bell1 :i* c be he>d a long di/ance & closely resembles a long bla/ bl[n on a fi%-horn4 ,burgl>-al>ms ,a unique burgl>-al>m trap may be made f a plate ( wood1 five by six in*es & half an in* ?ick1 a movable lev]1 & a brass /rip hav+ ! ends turn$ out4 ,^! are arrang$ z %[n 9 ,fig4 #h4 ,! brass /rip is fa/5$ to ! plate ) screws1 & ! ends ext5d out = half an in* f ! bo>d4 ,! lev] is made f a /rip ( brass1 & ! upp] "p is b5t out s z to cle> ! /rip & screws t are "u x4 ,a hole is made at ! l[] end ( ! lev]1 ?r\gh :i* a brass r+ & ! end ( a spr+ may be fa/5$4 ,! opposite end ( ! spr+ is atta*$ to a screw1 & a wire c>ri$ f x to a b9d+-po/1 ,a4 ,ano!r wire connects ! back plate ) b9d+-po/ ,b4 ,a /r+ or piece ( f9e picture-wire is made fa/ to ! r+ & c>ri$ to any "p ( a room4 ,to set ! trap1 make ! block fa/ 9 any conv5i5t place1 su* z ! door-cas+ or ! surbase1 & c>ry ! /r+ out f ! trap & fa/5 ! end ( x4 ,any "o runn+ aga9/ x 9 ! d>k w draw ! lev] ov] to ! "r side & connect ! circuit4 ,illu/ration3 ,,fig4 #h ,illu/ration3 ,,fig4 #i ,illu/ration3 ,,fig4 #aj ,:5 sett+ ! trap1 h ! /r+ adju/$ s t ! lev] is 9 a v]tical position1 z %[n 9 ! draw+ ( ,fig4 #h4 ,:5 ! /r+ is di/urb$ x w pull ! top ( ! lev] ov] to ! "r side2 b if ! /r+ is brok5 by ! p]son runn+ aga9/ x1 ! spr+ atta*$ to ! bottom ( ! lev] draws x ov] to ! "r side ) a snap1 & ! top ( ! lev] goes to ! left side1 :5 ! circuit is clos$ & ! al>m giv54 ,?is trap is connect$ ! same z a pu%-button1 "o wire lead+ to ! bell1 ! o!r to ! batt]y2 !n ! batt]y & bell are connect$ toge!r s t :5 ! circuit is clos$ ! bell w r+ until "s "o ?r[s a swit* op5 to break x4 ,ano!r =m ( circuit-clos] is %[n 9 ! door-trap 7,fig4 #i74 ,?is is a wood5 block t re/s on ! floor close to ! bottom ( a door1 & is held 9 place by means ( f\r %>p-po9t$ nails driv5 d[n ?r\gh ! corn]s ( ! block4 ,! po9ts %\ld project a qu>t] ( an in* or m1 accord+ to :e!r ! block is on a h>d floor or on a c>pet4 ,! front edge ( ! block is bevell$ s t ! bottom ( a door t fits closely to ! floor w pass ov] x4 ,! block is five by sev5 in*es1 & ?ree-qu>t]s ( an in* ?ick4 ,at ! left side a /rip ( metal 7,a7 is held close to ! block ) /raps or wide /aples driv5 ov] x1 b n s close b t x c move freely back & =?4 ,to ! front end a r\nd piece ( wood is made fa/4 ,?is is ! bump] aga9/ :i* ! door w /rike :5 op5$4 ,at ! middle ( ! /rip a screw is rivet$ fa/2 or x may be a ma*9e-screw let into a ?read$ hole 9 ! metal4 ,at ! "r side ( ! block ano!r /rip ( metal 7,b7 is atta*$1 b ?is is held fa/ ) a screw at ! middle & a screw-eye & wa%] at ! re> end to act z a b9d+-po/4 ,! front end ( ?is /rip is turn$ up s z to =m a /op2 !n a movable lev] 7,c7 m\nt$ ov] bo? /rips1 ) "o end b5t up1 is atta*$ to ! block ) a screw4 ,a slot is cut at "o end s t ! screw 9 ! movable /rip 7,a7 w move freely 9 x1 & ne> ! o!r end a small hole is made to receive ! end ( a spiral spr+ 7,d74 ,to set ! trap1 ! block is plac$ on ! floor & ! wires f batt]y & bell are made fa/ to ! b9d+-po/s4 ,! spr+ ,d keeps ! lev] ,c away f ! /rip-end ,b1 :ile at ! same "t x ?r[s ! /rip ,a =w>d4 ,:5 ! door is op5$ x %oves ! bump] & /rip ,a back ?r\gh ! /aples1 :ile ! screw op]ates lev] ,c & causes its loose end to come into contact ) ! end ,b1 !reby clos+ ! circuit & r++ ! bell or buzz]4 ,:5 ! door is clos$ aga9 ! spr+ draws lev] ,c away f ,b1 & ! circuit is op5$4 ,! block acts z an ob/ruction z well z an al>m1 = ! p9s w hold 9 ! floor & ! little block w /& its gr\nd4 ,a simple =m ( contact = doors is %[n at ,fig4 #aj4 ,?is is simply two /rips ( spr+-brass b5t z %[n1 & screw$ fa/ on ei!r side ! crack ( a door1 at ! h+e side1 s t :5 ! door is op5$ "o piece ( metal be>s on ! o!r & ! circuit is clos$4 ,?is is to be op]at$ 9 connection ) a swit*1 s t ! circuit may be op5$ 9 ! daytime :5 ! door is 9 use4 ,signals & ,al>ms ,!re are _m diff]5t k9ds ( electric call-signals us$ 9 & ab\t ! h\se2 among ^! are "s t a boy c readily make--= example1 ! ord9>y call-buttons & ! signals betwe5 h\se & /able or o!r out-build+s4 ,a portable call-bell1 or al>m1 is "o ( ! mo/ conv5i5t ?+s 9 any home4 ,x may be tempor>ily rigg$ up f "o room to ano!r1 or f "o floor to ! next1 ! small1 flexible wire be+ run ov] ! tops ( door-cas+s1 :]e x is held by slim nails or p9s driv5 into ! wood-"w4 ,! ma9 t]m9al ( ?is portable outfit consi/s ( a wood5 box t w hold a l>ge dry-cell1 & to ! side ( :i* an electric bell or buzz] may be atta*$4 ,b9d+-po/s are arrang$ at ano!r side1 to :i* ! ends ( ! flexible wire-cord c be made fa/1 & a cov] fitt$ to ! box to hide ! batt]y & wir+4 ,! complete outfit1 except ! flexible wire-cord & pu%-button1 w appe> z %[n 9 ,fig4 #aa4 ,no def9ite size c be laid d[n = ! con/ruction ( ?is box1 z dry-cells v>y 9 size & %ape1 "s be+ long & ?91 :ile o!rs are %ort & fat4 ,by remov+ ! cov] & look+ into ! box1 x w appe> z %[n 9 ,fig4 #ab4 ,! c>bon is connect$ ) "o b9d+-po/ & ! z9c to "o ( ! poles ( ! bell4 ,! o!r bell-pole is connect$ ) ! rema9+ b9d+-po/1 & x requires b a swit* or pu%-button to close ! circuit betwe5 ! two b9d+-po/s4 ,?is is done by ! long l9e ( flexible wire-cord1 :i* may be ( ! silk or cotton cov]$ k9d1 hav+ ! two /r&s twi/$ toge!r z is cu/om>y ) flexible electric-light wire4 ,a pe>-%ap$ pu%-button may be connect$ at ! end ( ! l9e1 & ?is may be arrang$ at ! head ( a b$ or on a *air plac$ conv5i5tly ne> an invalid's c\*4 ,?is same app>atus is a v conv5i5t ?+ = a lectur] :]e a /]eopticon is us$4 ,a buzz] takes ! place ( ! bell1 :i* w\ld be too l\d 9 a hall or lecture-room1 & ! cord1 pass+ f ! app>atus close to ! op]ator1 is hung ov] ! lectur]'s /&1 or ! button held by him 9 ! h&1 to be press$ :5ev] he desires ! pictures *ang$4 ,illu/ration3 ,,fig4 #aa ,illu/ration3 ,,fig4 #ab ,illu/ration3 ,,fig4 #ac ,?is app>atus c be us$ also 9 connection ) an al>m-clock1 :]e ! w9d+-key is expos$ at ! back1 z x is 9 mo/ ( ! nickel-cas$ clocks t are op]at$ by a spr+ & :i* h to be w\nd ea* day4 ,= ?is purpose obta9 a piece ( h>d rubb] or fibre1 "o-sixte5? ( an in* ?ick1 an in* long1 & half an in* wide4 ,a piece ( /\t c>d-bo>d or a ?9 piece ( h>d-wood soak$ 9 hot p>aff9e w answ] j z well1 if ! fibre or rubb] _c be _h4 ,bore a small hole at ! two upp] corn]s & "o at ! middle ne> ! l[] edge4 ,obta9 ?ree g>t]-clips1 ) spr+s1 & rivet "o ( !m fa/ to ! little plate ( non-conduct+ mat]ial4 ,cut two l5g?s ( old brass wat*-*a91 f\r in*es long1 or obta9 eight in*es ( *a9 at a h>dw>e-/ore1 & divide x 9 half4 ,atta* a g>t]-clip to "o end ( ea* piece1 & make ! o!r end fa/ 9 ! holes at ! corn]s ( ! small plate z %[n 9 ,fig4 #ac4 ,?is w be ! connector & w close ! circuit :5 ! al>m goes (f4 ,:5 ! clock is w\nd & ! al>m-spr+ is tight1 cat* "o b9d+-po/ ) a clip at ! end ( a *a9 & ! o!r po/ ) ! rema9+ clip4 ,place ! clock ne> ! box & grasp ! al>m-key ) ! clip on ! plate4 ,:5 ! al>m goes (f ! bell on ! clock w beg9 to r+1 & :5 ! key has made "o revolution x twi/s ! two pieces ( *a9 toge!r1 closes ! circuit1 & ! electric bell r+s until "s "o unfa/5s "o ( ! clips on ! b9d+-po/s & breaks ! circuit4 ,! great advantage 9 ?is d\ble-al>m outfit is t x keeps ! bell r++ until ! att5tion ( ! sleep] is attract$4 ,! bell on ! clock w /op r++ directly ! spr+ is unw\nd or run d[n2 b 9 s do+ x twi/s ! *a9 & sets ! electric me*anism 9 motion1 to run until x is /opp$1 or until ! batt]y pol>izes or is exhau/$4 ,a ,d9+-table ,call ,"o ( ! mo/ conv5i5t ( h\se electric-calls is t betwe5 ! d9+-room & ! butl]'s pantry or ! kit*51 its purpose be+ to summon ! waitress )\t ! necessity ( r++ a bell at ! table1 or call+4 ,!re are v>i\s =ms ( pu%-buttons = ?is purpose--"s emb$d$ 9 ! floor1 o!rs hang+ f ! c5tre light1 & o!rs aga9 :]e ! wire runs up f "u ! table1 & ! pe>-%ap$ pu% re/s on ! clo? )9 easy rea*4 ,^! la/ are good en\gh 9 _! way1 b are inconv5i5t1 unsightly1 & q liable to get out ( ord]4 ,9 ord] to use ! floor-pu% ! table mu/ /& 9 exactly ! "r place2 ) ! drop-/r+ f a *&eli] ! cord is cont9ually gett+ 9 ! way2 & z = ! portable pu% t comes f "u ! table1 "o mu/ be =ev] hunt+ = ! button e "t ! table is set4 ,& yet x is q possible to avoid all ^! tr\bles & con/ruct an app>atus t is always 9 ord] & always available1 :]ev] ! table may be plac$4 ,a visitor at a c]ta9 h\se notic$ t ! numb] ( ! family pres5t at a meal 0 apt to v>y l>gely1 necessitat+ frequ5t l5g!n+s & %ort5+s ( ! table4 ,& yet ! waitress inv>iably appe>$ j at ! "r "t1 & :e!r "o end or ! o!r ( ! table 0 to be s]v$1 %e 0 always on ! spot :]e %e 0 ne$$4 ,! visitor tri$ to /udy x out1 b 0 f9ally oblig$ to ask = an explanation ( ! my/]y4 ,! boy ( ! h\se smil$ & intimat$ t he 0 responsible = ?is dome/ic miracle2 lat] on1 :5 d9n] 0 ov]1 he remov$ ! c5tre leaves f ! table & display$ ! simple app>atus t he _h con/ruct$ & :i* _h work$ = sev]al ye>s )\t adju/m5t or repairs4 ,! illu/ration 7,fig4 #ad7 repres5ts ! frame ( a d9+-table ) ! middle cross-b> made fa/ to ! side-rails1 s z to support ! me*anism4 ,at bo? ends1 & inside ! rail1 pu%-buttons are arrang$ & wires c>ri$ f !m to b9d+-po/s close at h&1 z may be se5 at ! left side4 ,! cross-b> at ! middle ( ! table supports a l>ge spool on :i* ! flexible cord is w\nd1 & kept taut by means ( a clock-spr+4 ,?is spool takes up ! slack betwe5 ! ends ( ! table :5 x is l5g!n$ or %ort5$1 :ile ! small] "o opposite x keeps taut ! fe$-wires t come up ?r\gh ! floor4 ,a %ort di/ance f ! floor ! wire is provid$ ) a connector1 s t :5 ! rug is remov$ ! fe$-wires may be disconnect$ & slipp$ d[n4 ,! l>ge spool c be _h at any dry-goods /ore :]e braids or fancy cords are kept4 ,x %\ld be ab\t f\r in*es long1 ?ree in*es 9 diamet]1 & ) sides ?ick en\gh to enable screws to be driv5 into x )\t fe> ( splitt+ ! wood4 ,an old clock-spr+ is atta*$ at "o side ( ! spool1 :ile at ! o!r two circul> b&s ( brass are made fa/1 "o )9 ! o!r4 ,an axle ( /\t wire %\ld be driv5 ?r\gh ! spool2 b if ! hole is too l>ge1 wood5 plugs may be glu$ 9 at ea* end s t a front view ( ! spool w appe> z %[n at ,a4 ,! metal b&s are cut ) %e>s f %eet-brass1 & are atta*$ ) f9e /eel nails1 ! heads ( :i* are driv5 9 flu% ) ! wood4 ,a hole is made 9 ! side ( ! spool1 close beside ea* b&1 s t ! ends ( wires may be br\ght ?r\gh !m & atta*$ to ! b&s4 ,?is arrangem5t is illu/rat$ at ,b1 & at ,c ! opposite end is %[n1 ) its clock-spr+1 "o end ( :i* is made fa/ to ! side ( ! spool & ! o!r to ! cross-rail4 ,a small r\nd piece ( wood is slipp$ ov] ! axle1 at ! spr+ side1 & projects a qu>t] ( an in* beyond ! spr+4 ,?is is to keep ! spr+ away f ! arm t /&s out on t side to hold ! spool 9 place4 ,illu/ration3 ,,fig4 #ad ,a ,,d9+-,,table ,,call ,ab\t half an in* ( space is left betwe5 ! spool & ! arm at ! opposite side1 s t ! spr+ contact-/rips may be made fa/ to ! arm & /ill h room to act4 ,a view look+ d[n on ! spool & spr+s is %[n at ,d1 & ,e illu/rates ! arrangem5t ( ! circul> /rips & ! spr+ contact-/rips4 ,if ! table is to rema9 p]man5tly 9 ! same position1 only "o spool w be requir$1 = ! floor wires c come up & connect directly ) ! contact-/rips4 ,b if ! table is to be mov$ ab\t1 a t5sion-spool1 indep5d5t ( ! pu%-button wires1 is necess>y s t ! position ( ! table may be *ang$ )\t unw9d+ ! l>ge spool & dropp+ ! cords d[n to ! floor4 ,! small] spool is made & m\nt$ 9 ! same mann]1 & %\ld be plac$ close to ! l>ge "o4 ,b a light] spr+ w op]ate x4 ,"o end ( a d\ble wire-cord is made fa/ to b9d+-po/s1 m\nt$ on a yoke ( h>d rubb] or fibre1 s t ! t]m9als w be kept ap>t1 z %[n at ,f4 ,! o!r ends are pass$ ?r\gh ! holes at "o side ( ! small spool & sold]$ fa/ to ! circul> /rips1 or a small screw may be pass$ d[n ?r\gh ! hole1 b9d+ ! wire & t\*+ ! edge ( "o /rip4 ,take c>e t x does n t\* ! o!r /rip4 ,! cord is !n w\nd on ! spool1 & x is slipp$ 9 place s t ! loose end ( ! spr+ is caught & held ov] a nail or screw-head4 ,turn ! spool ov] sev]al times to p>tially w9d ! spr+2 !n atta* ! t]m9als to ! wires t come up f ! floor & ! t5sion ( ! spr+ w draw ! wires taut4 ,! two contact-/rips ( brass1 t re/ aga9/ ! brass circles1 h insulat$ wires lead+ out f !m 9 ord] to connect !m ) ! correspond+ wires lead+ f ! /rips ( ! l>g] spool4 ,a simple way to m\nt ! spools is %[n at ,a 9 ,fig4 #ae4 ,a not* is cut 9 ! face ( ! blocks l>ge en\gh to admit ! axle2 !n a face-plate is screw$ ov] ! end ( ! block to hold ! axle 9 place4 ,?is arrangem5t makes x easy to remove ! spool1 9 case ( necessity1 )\t deta*+ ! arms f ! cross-rail4 ,illu/ration3 ,,fig4 #ae ,two sets ( wires are w\nd on ! l>ge spool1 "o lead+ to ! "r-h& & ! o!r to ! left-h& pu%-button on ! table-rails4 ,! ends ( ! wires are arrang$ s t "o lead+ f bo? directions is made fa/ to "o circul> /rip on ! spool1 ! o!r two be+ atta*$ to ! rema9+ b&4 ,?is is m cle>ly %[n at ,b 9 ,fig4 #ae1 :]e ! ends are visible z !y are twi/$ toge!r & pass ?r\gh _! respective holes4 ,! spool is !n turn$ ov]1 & six or eight feet ( wire w\nd on f ea* side4 ,! spr+ is coil$ up & caught on ! nail or screw1 & ! ends ( ! wires are made fa/ to ! b9d+-po/s ne> ! pu%-buttons4 ,! wires f bo? pu%-buttons are !n 9 connection ) ! circul> b&s1 :i* 9 turn are connect$ to ! b&s on ! small] spool1 & lead ! curr5t d[n ?r\gh ! floor wires4 ,by pu%+ ! button at ei!r end ! circuit is clos$ & ! buzz] or bell is rung 9 ! kit*5 or pantry4 ,arrang$ 9 ?is mann]1 ! wires are kept (f ! floor1 no matt] :]e ! table is mov$1 & x c be drawn op5 z wide z may be f\nd necess>y to put 9 leaves4 ,:5 clos$ aga91 ! spr+ causes ! l>ge spool to revolve & w9d up ! wire4 ,*apt] ,,vi ,,curr5t-,,detectors ,,& ,,galvanomet]s ,a curr5t-detector is a necess>y "p ( ! amateur electrician's equipm5t2 te*nically1 ?is piece ( app>atus is call$ a galvanoscope4 ,:5 a wire or a numb] ( !m are br\ght ne> a magnetic ne$le or a small compass1 ! ne$le w be deflect$ f its nor? & s\? l9e & w po9t ea/ & we/1 or we/ & ea/1 accord+ to ! direction 9 :i* ! curr5t is pass+ ?r\gh ! wires4 ,all wires t are conduct+ electricity h a magnetic field1 & :5 br\ght ne> ! magnetiz$ ne$le ( a compass !y h ! p[] to act on x ! same z ano!r & /rong] magnet w\ld4 ,! action ( detectors dep5ds ^u two ?+s--fir/1 ! magnetiz$ ne$le t1 :5 prop]ly balanc$1 w po9t nor? & s\?2 &1 secondly1 a curr5t ( electricity pass+ ?r\gh a wire or wires held above ! ne$le1 or bo? above & bel[ x4 ,?is is m cle>ly %[n 9 ,fig4 #a1 :]e a compass is re/+ on a wire connect$ to a batt]y4 ,! wire also passes ov] ! top ( ! compass1 :i* d\bles ! electro-magnetic field4 ,:5 ! compass 7) ! ne$le po9t+ nor?7 is re/+ on ! wire t is atta*$ to ! z9c pole ( a batt]y1 & :5 ! end ( ! wire t passes back ov] ! top ( ! compass is atta*$ to ! c>bon pole1 ! ne$le w fly ar\nd & po9t to ! ea/4 ,:5 ! wires are rev]s$1 ! ne$le w po9t to ! we/4 ,?us ! comb9ation ( a batt]y or o!r s\rce ( electric curr5t1 a magnetic ne$le1 & a coil ( wire prop]ly arrang$1 make an in/rum5t t w detect electric curr5ts & may be correctly call$ a curr5t-detector4 ,! pressure ( m or less curr5t is det]m9$ by in/rum5ts w\nd ) wire ( diff]5t sizes2 ! f9] ! wire ! m s5sitive ! in/rum5t1 & consequ5tly ! m delicate4 ,a v weak curr5t c only be detect$ ) a delicate & s5sitive in/rum5t4 ,! co>s] ! wire & ! l>g] ! in/rum5t1 ! bett] x w be = te/+ /rong curr5ts t w\ld p]haps burn out ! f9e wire ( ! m delicate app>atus4 ,?is in/rum5t1 :5 plac$ betwe5 a s\rce ( electricity & a piece ( app>atus1 su* z a bell1 a motor1 or lamp1 does n weak5 ! curr5t1 = x requires no wa/e ( electricity to op]ate ! magnetic ne$le4 ,consequ5tly1 :5 a v weak curr5t is be+ us$ = any te/s1 x is well to place a detector betwe5 ! batt]y & ! app>atus to %[ t ! curr5t is actually pass+ ?r\gh ! wire4 ,a simple detector is made by w9d+ fifte5 or tw5ty feet ( cotton-insulat$ copp] wire ,no4 #bf or #bh ar\nd ! l[] end ( a dr9k+-glass4 ,leave six in*es ( ea* end loose2 !n aft] slipp+ ! coil f ! glass1 tie ! wires ) ?read at lea/ f\r times ar\nd ! circle1 s z to b9d ! wires toge!r4 ,press two sides ( ! hoop toge!r s z to flatt5 x2 !n ) p>aff9e atta* ! coil to a squ>e block ( wood1 z %[n 9 ,fig4 #b4 ,illu/ration3 ,,fig4 #a ,illu/ration3 ,,fig4 #b ,illu/ration3 ,,fig4 #c ,illu/ration3 ,,fig4 #d ,illu/ration3 ,,fig4 #e ,f a ?9 clock-spr+1 n m ?an ?ree-eigh?s ( an in* wide1 cut a piece two in*es & a half long1 & ) a /\t pair ( t9-%e>s cut ! ends s z to po9t !m1 z %[n 9 ,fig4 #c ,a4 ,) two pair ( pli]s b5d a hump at ! middle ( ! /rip on ! dott$ l9es %[n 9 ,a1 s t a side-view w appe> l ,b 9 ,fig4 #c4 ,turn ?is /rip ov] on a h>d-wood block or a piece ( lead1 & ) a /\t /eel-wire nail & a hamm] d5t ! inv]t$ ,v at ! middle s t x w re/ on ! top ( a ne$le-po9t )\t fall+ (f4 ,) ?ree little pieces ( wood make a bridge & atta* x to ! wood5 base ov] ! p>aff9e t holds ! wire-coil1 & drive a ne$le d[n 9 ! middle ( x1 tak+ c>e t x does n g ?r\gh ! back & t\* ! wires und]nea?4 ,on ?is ne$le hang ! /rip ( /eel spr+1 &1 if x does n prop]ly balance1 trim x ) ! %e>s or a h>d file until x is adju/$ prop]ly4 ,rub ?is piece ( /eel ov] ! pole ends ( a l>ge horse%oe magnet1 or place x )9 ! helix ( a l>ge coil & turn a p[]ful curr5t ?r\gh ! coil4 ,?is w magnetize ! /rip ( /eel1 :i* w !n become a magnetic ne$le & hold ! magnetism4 ,atta* two b9d+-po/s to corn]s ( ! block1 & make ! loose ends ( ! coil-wires fa/ to !m4 ,y n[ h a curr5t-detector1 or galvanoscope1 z %[n 9 ,fig4 #d4 ,turn ! block s t ! ne$le po9ts to nor? & s\? & p>allel to ! /r&s ( wire4 ,:5 ! conductors f ! poles ( a batt]y or dynamo are made fa/ to ! b9d+-po/s1 ! ne$le w fly ar\nd to a position at "r angles to t :i* x fir/ occupi$1 z %[n by ! dott$ l9e ,a ,a 9 ,fig4 #d4 ,:5 ! connection is brok5 ! ne$le w turn ar\nd aga9 & po9t to nor? & s\?1 s9ce ! magnetic field ab\t ! wire ceases & disappe>s ! in/ant ! circuit is brok54 ,?is is "o ( ! /range & unkn[n ph5om5a ( electricity1 = :ile ! curr5t ex]ts a =ce t deflects ! ne$le1 x does n de/roy its magnetism4 ,on ! break+ ( ! contact1 no matt] h[ long x may h held ! ne$le away f its true c\rse1 x aga9 po9ts to nor?1 & its magnetism is n affect$4 ,ano!r simple curr5t-detector is %[n 9 ,fig4 #e4 ,a piece ( broom/ick is saw$ 9 half & bo? pieces are made fa/ to a block :i* is m\nt$ on a base ( wood ?ree-qu>t]s ( an in* 9 ?ickness4 ,! v]tical block %\ld measure five in*es long1 ?ree in*es high1 & five-eigh?s ( an in* ?ick4 ,! half-circul> pieces ( wood are m\nt$ s t ! flat surfaces are ?ree in*es ap>t & ! l[] edges are "o in* above ! base-block4 ,^! may be held 9 place ) glue & screws driv5 ?r\gh ! back ( ! v]tical block & into ! ends ( ! project+ half-circul> pieces4 ,! base-block is six in*es long & f\r in*es wide1 & ! v]tical block is m\nt$ on x "o in* f an edge4 ,! pieces ( broom/ick are two in*es long1 & at ! front ends a ?9 b> ( brass or copp] is screw$ fa/ to hold !m ap>t & 9 prop] position1 z %[n at ,a 9 ,fig4 #e4 ,to improve ! appe>ance ( ?is m\nt+1 all ! wood-"w may be /a9$ & %ellack$ be=e ! metal p>ts are atta*$4 ,) ,no4 #bf1 #bh1 or #cj cotton-insulat$ wire make f fifte5 to tw5ty wraps ab\t ! middle ( ! half-circul> pieces ( wood & c>ry ! ends d[n ?r\gh small holes 9 ! base-block & !nce ?r\gh grooves cut at ! "u side ( ! block to ! front corn]s1 :]e !y are to be made fa/ to b9d+-po/s4 ,a ne$le is to be set 9 ! base-block midway betwe5 ! two pieces ( half-circul> wood & ?r\gh ! /r&s ( wire4 ,great c>e mu/ be tak5 t ! ne$le does n t\* any b>e wires1 & z a precaution>y measure x w\ld be well to wrap ! ne$le ) a piece ( insulat+-tape :]e x passes ?r\gh ! /r&s ( wire4 ,n[ place on ! top ( x a magnetiz$ piece ( /eel1 z describ$ = ! detector %[n 9 ,fig4 #d4 ,z x may n always be conv5i5t to turn ! in/rum5t s t ! ne$le po9ts nor?1 a small b> ( magnetiz$ /eel or a /\t ne$le t has be5 magnetiz$ ) a horse%oe magnet or a helix1 may be laid across ! half-circul> wood pieces1 s t x is p>allel ) ! top lay] ( wires--9 fact1 x %\ld re/ on top ( !m4 ,by means ( ?is ne$le1 or b>1 ! magnetic piece ( /eel balanc$ on ! v]tical ne$le betwe5 ! upp] & l[] /r&s ( insulat$ wire may be held 9 "o position no matt] :i* way ! block is turn$4 ,:5 ! curr5t passes 9 ?r\gh "o b9d+-po/ & out ?r\gh ! o!r 7hav+ ?us travell$ ?r\gh ! coil on ! half-circul> blocks7 ! ne$le is deflect$ & po9ts out at ! brass b> & back at ! upright block4 ,:5 mak+ any ( ^! pieces ( app>atus1 :]e delicately balanc$ magnetic ne$les are employ$1 all p>ts ( ! m\nt+ blocks or o!r sections mu/ be put toge!r ) glue & brass nails or screws4 ,x w n d to use /eel or iron nails1 screw-eyes1 or wa%]s1 nor pieces ( %eet-iron1 t91 or /eel1 = !y w ex]t _! influ5ce on ! vital p>ts ( ! app>atus & s de/roy _! usefulness4 ,?is is n s important :5 mak+ buzz]s1 bells1 motor-induction coils1 or simil> ?+s1 b 9 delicate in/rum5ts1 :]e magnetic ne$les or electro-magnets are us$ = record+1 measur+1 or detect+1 iron & /eel p>ts %\ld be c>efully avoid$1 except :]e _! use is expressly indicat$4 ,an ,a/atic ,curr5t-detector ,a/atic curr5t-detectors & galvanomet]s are ^? hav+ two magnetic ne$les arrang$ ) ! poles 9 oppos$ directions4 ,! ord9>y magnetic or compass ne$le po9ts to ! ,nor?1 & 9 ord] to deflect x a /rong magnetic field mu/ be creat$ ne> x4 ,= /rong electric curr5ts ! ord9>y s+le-ne$le curr5t-detector meets all requirem5ts1 b = weak curr5ts x w be necess>y to arrange a pair ( ne$les1 "o above ! o!r1 ) _! poles 9 opposite directions1 & plac$ )9 or ne> "o or two coils ( f9e wire4 ,?is app>atus w be affect$ by ! weake/ ( curr5ts1 & w indicate _! pres5ce un]r+ly4 ,! ^w 8a/atic0 means hav+ no magnetic directive t5d5cy4 ,if ! ne$les ( ?is a/atic pair are sep>at$ & pivot$ ea* w po9t to ,nor? & ,s\?1 aft] ! ord9>y fa%ion4 ,= all a/atic in/rum5ts we mu/ employ two magnetic ne$les 9 p>allel1 ei!r side by side or "o above ano!r1 z %[n 9 ,fig4 #f1 ) ! ,n & ,s poles arrang$ z indicat$4 ,?is comb9ation is usually call$ ,nobili's pair4 ,if bo? ne$les are ( equal l5g? & magnetic /r5g?1 !y w be a/atic1 = ! p[] ( "o c\nt]balances t ( ! o!r4 ,z a consequ5t nei!r po9ts to ,nor?4 ,a comp\nd ne$le ( ?is =m requires b a v feeble curr5t to turn x "o way or ! o!r1 & ?is is ! !ory ^u :i* all a/atic in/rum5ts are con/ruct$4 ,a simple a/atic curr5t-detector may be made f a s+le coil ( f9e insulat$ wire1 a pair ( magnetic ne$les1 & a support f :i* to susp5d !m1 toge!r ) a base-block4 ,= ! base-block obta9 a piece ( :ite-wood1 p9e1 or cypress1 f\r in*es squ>e & ?ree-qu>t]s ( an in* ?ick4 ,s&-pap] x smoo?1 & !n give x two or ?ree coats ( %ellac4 ,f a /rip ( copp] or brass 7d n use t9 or iron7 make a bridge1 9 ! =m ( an inv]t$ ,v1 sev5 in*es high1 us+ metal "o-sixte5? ( an in* ?ick & half an in* wide4 ,?is bridge is to be screw$ to ! outside ( ! block1 z %[n at ,fig4 #g1 s t x w be rigid & firm4 ,a small hole is drill$ ?r\gh ! top ( ! bridge to admit a screw-eye = ! t5sion4 ,make a coil ( ,no4 #cj insulat$ wire1 us+ t5 or fifte5 feet1 & w9d x ab\t ! base ( a dr9k+-glass to %ape x2 !n remove x & tie ! coil1 9 sev]al places1 ) cotton or silk ?read1 s z to hold ! /r&s toge!r4 ,%ape x 9 ! =m ( an ellipse & make x fa/ to ! middle ( ! base-bo>d ) small brass or copp] /raps1 & copp] tacks or brass screws4 ,be v c>eful n to use iron1 /eel1 or t9 ab\t ?is in/rum5t1 z ! pres5ce ( ^! metals w\ld deflect ! ne$les & make !m useless4 ,sep>ate ! /r&s at ! top ( ! coil s t "o ( ! ne$les may be slipp$ ?r\gh to occupy a position 9 ! middle ( ! coil4 ,ord9>y l>ge compass ne$les may be employ$ = ?is app>atus1 or magnetiz$ pieces ( highly temp]$ /eel piano-wire w answ] j z well4 ,illu/ration3 ,,fig4 #f ,illu/ration3 ,,fig4 #g ,illu/ration3 ,,fig4 #h ,a %ort piece ( brass1 copp]1 or wood w act z ! c>ri]-b> = ! ne$les4 ,^! %\ld be pu%$ ?r\gh holes made 9 ! b>1 & held 9 place ) a drop ( %ellac or melt$ p>aff9e4 ,a small hole is drill$ at ! top ( ! b>1 or a small eye c be atta*$1 ?r\gh :i* to pass ! end ( a ?read4 ,! upp] end ( ! ?read is ti$ 9 a screw-eye1 ! screw "p ( :i* passes up ?r\gh ! hole 9 ! bridge & into a wood5 button or knob1 :i* c be turn$ to %ort5 or l5g!n ! ?read1 & s raise or l[] ! ne$les4 ,! l[] ne$le mu/ be pivot$ at an equal di/ance betwe5 ! upp] & l[] p>ts ( ! coil4 ,two b9d+-po/s are arrang$ at ! corn]s ( ! base1 & ! ends ( ! coil wires are atta*$ "u ! screw-heads4 ,! 9-&-out wires are to be made fa/ "u ! copp] wa%]s on ! screw-eyes4 ,ow+ to ! a/atic qualities ( ! ne$les1 ! base-block does n h to be turn$ s t ! coil may face ,nor? & ,s\?1 z 9 ! curr5t-detector4 ,:5 ! slighte/ curr5t ( electricity passes ?r\gh ! coil x in/antly affects ! ne$les1 turn+ !m to ! "r or left accord+ to ! way 9 :i* ! curr5t is runn+ ?r\gh ! coil4 ,an ,a/atic ,galvanomet] ,! s5sitiv5ess ( an a/atic detector may be increas$ by ! add$ /r5g? ( ! coil-field = a giv5 curr5t4 ,!re are two ways ( accompli%+ ?is result4 ,! numb] ( turns ( wire may be increas$ 9 ! coil1 or two coils may be us$1 plac$ side by side4 ,! latt] me?od is ! m satisfactory1 s9ce !n ! coil does n h to be op5$ at ! top to admit ! l[] ne$le1 ! latt] be+ dropp$ d[n betwe5 ! coils4 ,?is app>atus is %[n 9 ! illu/ration ( an a/atic galvanomet]1 ,fig4 #h4 ,! g5]al arrangem5t ( ne$les1 bridge1 & coils1 is ! same z describ$ = ! a/atic curr5t-detector4 ,ea* coil is made sep>ately ( t5 feet ( ,no4 #cj insulat$ copp] wire1 w\nd ab\t ! base ( a dr9k+-glass to %ape x2 !n press$ into elliptical %ape1 & fa/5$ to a base-block ) a brass or copp] /rip1 & held d[n ) small brass screws4 ,! base-block %\ld be f\r in*es squ>e1 ) ! corn]s saw$ (f4 ,smoo? ! block ) s&-pap]1 & !n give x sev]al good coats ( %ellac4 ,! bridge is made f brass "o-sixte5? ( an in* ?ick & half an in* wide4 ,! coils ( wire are arrang$ ab\t half an in* ap>t1 & at bo? ends a small sep>ator-block is plac$ betwe5 ! coils1 & !n b\nd ) silk or cotton ?read4 ,a circul> indicator disk ( bri/ol-bo>d %\ld be cut out & m>k$ & atta*$ to ! top ( ! coils ) a few drops ( seal+-wax or p>aff9e2 !n ! ne$les are susp5d$ s z to hang prop]ly1 "o above ! c>d1 ! o!r betwe5 ! coils4 ,?ree b9d+-po/s are plac$ at "o end ( ! block1 & to !m ! end wires ( ! coils are l$ & atta*$4 ,to ! fir/ b9d+-po/ 7at ! left7 ! /r& ( wire lead+ to ! fir/ coil is atta*$4 ,x leads 9 & is coil$ z ! h&s move on a clock1 f left to "r4 ,! lead+-out wire f ! coil is made fa/ to ! middle po/4 ,! lead+-9 wire to ! second coil is also made fa/ to ! middle po/4 ,! coil wires %\ld h ! turns 9 ! same direction z ! fir/ coil2 !n ! la/ wire is atta*$ to ! "r-h& po/4 ,:5 mak+ connections = a /rong curr5t1 use an end & middle po/4 ,?is arrangem5t w op]ate b "o coil4 ,= v weak curr5ts make ! lead+ 9 & out wires fa/ to ! end-po/s4 ,?is latt] plan is m cle>ly %[n 9 ! diagram1 ,fig4 #i4 ,a & ,b repres5t ! coils1 ,c1 ,d1 & ,e ! b9d+-po/s4 ,! curr5t1 ent]+ at ,c1 passes ?r\gh ! coil ,a 7z ! h&s move ab\t ! dial ( a clock7 & out at ,d1 :]e connection is made ) ! wire lead+ 9 to coil ,b4 ,! curr5t passes ?r\gh ?is coil 9 ! same direction z ! clock h&s move1 & out to po/ ,e4 ,be c>eful to arrange ! wir+ & connections aft] ?is exact mann]1 o!rwise ! in/rum5t w n be ( any use4 ,! adju/m5t at ! top ( ! bridge may be made ) an inv]t$ screw-eye & a small cork into :i* ! eye c be screw$1 ?us rais+ or l[]+ ! ne$les to ! prop] position4 ,be sure to h ! ne$les 9 p>allel :5 at re/4 ,z ! ne$les & coils are v s5sitive x w\ld be well to cov] ! in/rum5t ) an inv]t$ glass j>4 ,a blue/one or gravity batt]y j> w answ] v well1 & aft] ! wires are connect$ to ! b9d+-po/s ! glass may be plac$ ov] ! entire app>atus4 ,a ,tang5t ,galvanomet] ,= te/+ ! v>i\s degrees ( int5sity ( a curr5t a tang5t galvanomet] is usually employ$4 ,9 ?is app>atus ! increas$ /r5g? is indicat$ by ! index-po9t] z x plays ov] a scale or graduat$ circle4 ,a simple tang5t galvanomet] may be made f a flat hoop ( wood-fibre or brass1 m\nt$ on a base by means ( two uprights1 toge!r ) ! necess>y compass ne$le1 an index-c>d1 insulat$ wire1 & b9d+-po/s = ! electrical connections4 ,?is piece ( app>atus is %[n 9 ,fig4 #aj4 ,x is built on a base-block six by sev5 in*es & ?ree-qu>t]s ( an in* ?ick4 ,! block %\ld be ( select$ wood1 & aft] x is made smoo? x %\ld be giv5 sev]al coats ( %ellac4 ,two upright pieces ( wood1 five in*es long1 half an in* ?ick1 & "o in* 9 wid?1 are screw$ fa/ to ! re> edges ( ! base-block to support ! hoop on :i* ! insulat$ wire is w\nd4 ,be c>eful n to use any iron or /eel 9 ! con/ruction ( ?is or any o!r record+ in/rum5t1 except :]e x is expressly /at$4 ,screws1 nails1 /aples1 or any bits ( an*or+ wire %\ld be ( copp] or brass4 ,/r+1 ?read1 or silk may be us$1 especially :]e coils ( wire are to be b\nd or fa/5$ to hoops or base-blocks4 ,! balance ( ! indicat+ ne$le is s delicate1 & ! s5sitiv5ess ( ! coils is s easily affect$1 t no?+ ab\t or ne> ! in/rum5ts %\ld be ( iron or /eel4 ,! hoop may be made ( v ?9 hickory wood1 /eam$ & b5t s z to =m a r+ six in*es outside diamet] & "o in* wide4 ,x is ev5 possible to con/ruct a satisfactory hoop f a ribbon ( br[n pap]1 roll$ & lapp$1 ! sev]al ?icknesses be+ glu$ z ! turns are made4 ,if a metal hoop is to be us$1 sold] ! ends ( a ?91 h>d ribbon ( brass1 copp]1 or z9c4 ,?is /rip %\ld be provid$ ) holes1 set 9 pairs ab\t f\r in*es ap>t1 all ar\nd ! hoop1 & :]e ! hoop is to be atta*$ to ! uprights two holes %\ld be made close to ! m>g9s ?r\gh :i* brass screws may pass4 ,across ! middle ( ! hoop a /rip ( wood six in*es long1 an in* wide1 & a qu>t] ( an in* ?ick is made fa/4 ,on ?is ! graduat$ c>d is plac$1 & at ! c5tre ! balanc$ magnetic ne$le is arrang$ on a pivot4 ,aft] ! cross-/ick is 9 place1 w9d five turns ( ,no4 #bd insulat$ copp] wire ab\t ! hoop1 keep+ x z ne>ly 9 ! c5tre z possible4 ,"o end ( ! wire 7! beg9n+7 is to be atta*$ to ! fir/ b9d+-po/ on ! front ( ! base1 & ! o!r end to ! second po/4 ,! wire %\ld be w\nd r\nd ! hoop 9 ! same direction z ! clock h&s travel ab\t a dial4 ,ano!r coil1 compos$ ( t5 turns ( wire1 is made ov] ! fir/ "o1 ! beg9n+ end be+ atta*$ to ! middle b9d+-po/ & ! la/ end to ! ?ird po/4 ,?is arrangem5t is %[n 9 ,fig4 #aa1 ,d & ,e repres5t+ ! coils1 :ile ,a1 ,b1 & ,c are ! b9d+-po/s4 ,! curr5t ent]s at ,a1 passes ?r\gh coil ,d1 & out at po/ ,b4 ,! next passage is 9 at ,b1 ?r\gh ,e1 & out at ,c4 ,a curr5t pass+ 9 at ,a w travel to ,b1 !nce ?r\gh ,e1 & out at ,c4 ,if ! lead+-9 wire is made fa/ to ,a1 & ! out wire to ,c1 ! curr5t w travel ?r\gh ! entire coil4 ,"u ?is plan "o or bo? coils may be us$ 7! %ort or long "o z desir$7 by mak+ connections ) ! fir/ & second b9d+-po/s1 ! second & ?ird1 or ! fir/ & ?ird1 z ! /r5g? ( ! curr5t w w>rant4 ,/rong curr5ts w deflect ! ne$le :5 travell+ ?r\gh a %ort coil1 b ! weak] ! curr5t ! m coils x w h to pass ?r\gh to prop]ly deflect ! ne$le & indicat+ po9t]4 ,illu/ration3 ,,fig4 #aj ,,fig4 #aa ,,fig4 #ab ,,fig4 #ac ,,fig4 #ad ,,fig4 #ae ,,tang5t ,,galvanomet]s ,:5 ! coils are all on1 ! hoop %\ld be atta*$ to ! uprights ) small brass screws driv5 ?r\gh holes 9 ! hoop & into ! wood4 ,! wire is b\nd to ! hoop by means ( ?reads or silk pass$ ?r\gh ea* pair ( holes 9 ! hoop1 & !n ti$ fa/4 ,f9e insulat$ wire may be us$ 9 place ( ! ?read1 b c>e %\ld be tak5 t ! insulation is 9 p]fect %ape on bo? ! b9d+ & coil wires2 o!rwise a %ort-circuit w quickly de/roy ! value ( ! coils4 ,! hoop %\ld n t\* ! base-block1 b %\ld cle> x by a qu>t] or half an in*4 ,make ! coil ends fa/ 7z describ$ = ! a/atic galvanomet] & illu/rat$ at ,fig4 #i7 by means ( b9d+-po/s4 ,! wires ne$ n be c>ri$ ov] ! top ( ! block1 b may run ?r\gh holes "u ! hoop & along grooves cut 9 ! "u side ( ! block & lead+ to ! foot ( ! b9d+-po/s4 ,! graduat$ c>d %\ld be made f a piece ( /\t bri/ol-bo>d or heavy c>d-bo>d hav+ a smoo?1 h>d surface4 ,x is laid out ) a p5cil or p5 compass1 z %[n at ,fig4 #ab1 & %\ld be ?ree in*es 9 diamet]4 ,! c>d is plac$ on ! wood /rip or l$ge1 s t ! z]o m>ks w be at ! front & re>1 or at "r angles to ! hoop & coils ( wire4 ,! compass ne$le1 :5 at re/1 %\ld lie p>allel ) ! coils1 s t ! curr5t w deflect ! ne$le & s5d ! indicator ar\nd to "o side or ! o!r ( z]o1 accord+ to ! direction 9 :i* ! curr5t is pass+ ?r\gh ! coils4 ,?is is m cle>ly %[n at ,fig4 #ac4 ,! circle repres5ts ! outside diamet] ( ! c>d2 ! d>k cross-piece1 ! magnetic ne$le2 & ! po9t$ indicator1 a /iff pap]1 or v ?9 brass or copp] /rip1 cut & atta*$ to ! ne$le ) %ellac or p>aff9e4 ,:5 at re/ ! magnetic ne$le %\ld be p>allel to ! coils4 ,to insure ?is ! in/rum5t mu/ be mov$ s t ! l9es ( wire =m+ ! coil w run ,nor? & ,s\?4 ,o!rwise ! ,n-seek+ end ( ! magnetic %aft w po9t to ,nor?1 irrespective ( ! position occupi$ by ! wire coil4 ,! magnetic ne$le may be made z describ$ = ! compass 7see *apt] iv41 ,magnets & ,induction ,coils74 ,x %\ld be arrang$ to re/ on a brass pivot press$ d[n into ! cross-piece ( wood4 ,! indicator-ne$le may be cut f /iff pap]1 ?9 %eet-fibre1 or v ?9 cold-roll$ brass or copp]1 ! latt] be+ commonly kn[n z h>d or spr+-brass4 ,only "o po9t] is really necess>y--t po9t+ to ! front4 ,b ! weight ( ! mat]ial w\ld h a t5d5cy to upset ! magnetic ne$le1 & !re=e x is bett] to c>ry an equally long tail or end1 on ! opposite side1 to prop]ly balance ! ne$le4 ,a v weak curr5t1 pass+ 9 ?r\gh ! fir/ po/ & out at ! ?ird1 w cause ! indicator to be deflect$ consid]ably1 or s t x w po9t f #dj to #fj on ei!r side ( ! z]o po9t1 accord+ to ! direction 9 :i* ! curr5t is runn+ ?r\gh ! coils4 ,:5 n 9 use ! magnetic ne$le %\ld be remov$ f ! pivot1 & plac$ 9 a box or o!r safe place1 :]e x w n become damag$4 ,a diff]5tly arrang$ tang5t galvanomet] is %[n at ,fig4 #ad4 ,z ! l9e ( b9d+-po/s w\ld indicate1 !re are sev]al coils ( wire ab\t ! circle or hoop4 ,?is galvanomet] c be us$ = ei!r /rong or weak curr5ts1 s9ce x is w\nd ) bo? co>se & f9e insulat$ wire4 ,an upright plate ( wood1 sev5 in*es wide & eight in*es high1 supports ! hoop & compass4 ,! top corn]s are saw$ (f1 & f\r in*es above ! bottom a /raight cut is made across ! plate1 five in*es wide & ar*$ 9 a half-circle five in*es 9 diamet]4 ,a %elf ( wood a qu>t] ( an in* ?ick1 ?ree in*es wide1 & five in*es long is made1 & atta*$ z a l$ge 9 ?is ar*$ op5+1 s t a compass ?ree in*es 9 diamet] may re/ ^u x4 ,! %elf %\ld be arrang$ s t x w hold ! compass 9 ! middle ( ! circle in/ead ( at "o side4 ,! turns ( wire w !n be 9 l9e ) ! magnetic ne$le :5 ! latt] is at re/4 ,a base-block sev5 in*es long1 ?ree in*es wide1 & sev5-eigh?s ( an in* ?ick is cut & atta*$ to ! upright plate by driv+ screws ?r\gh ! bottom ( ! plate & into ! re> edge ( ! base4 ,! corn]s are to be cut f ! front ( ! base1 & t5 small holes are to be bor$ half an in* out f ! upright & ab\t a qu>t] ( an in* ap>t4 ,^! are = ! end wires t w ext5d d[n f ! coils1 & f !nce to ! b9d+-po/ holes4 ,grooves may be cut 9 ! "u side ( ! base-block = ! wires to re/1 91 z %[n at ,fig4 #ae1 :i* is a view ( ! inv]t$ base4 ,a hoop is made ( brass1 six in*es 9 diamet] & an in* wide4 ,x is held to ! upright plate ) copp] wire pass$ ?r\gh a small hole1 bor$ at ! inn] edge ( ! b&1 & back ?r\gh two small holes bor$ 9 ! plate1 ! ends be+ twi/$ toge!r at ! back ( ! plate4 ,a wire at ! top1 bottom1 & bo? sides w be suffici5t to hold x securely 9 place4 ,! fir/ coil ( wire is made ( ,no4 #ah insulat$1 & ! beg9n+ end is made fa/ to ! b9d+-po/ at ! left4 ,! wire is c>ri$ up ?r\gh ! fir/ hole "u ! hoop1 & aft] ?ree turns h be5 made ! end is c>ri$ d[n ?r\gh ! second hole & made fa/ to ! foot ( ! second b9d+-po/4 ,! second coil is ( ,no4 #bd insulat$ copp] wire4 ,! beg9n+ end is made fa/ to ! second b9d+-po/1 c>ri$ up ?r\gh ! ?ird hole1 giv5 five turns ab\t ! hoop1 drawn d[n ?r\gh ! f\r? hole1 & atta*$ to ! ?ird b9d+-po/4 ,! ?ird coil is ( ! same size wire b has t5 turns4 ,! f\r? coil has tw5ty turns1 & ! fif?1 ( ,no4 #cj insulat$ wire1 has ?irty turns1 ! la/ end be+ atta*$ to ! po/ at ! "r4 ,9 all ! coils !re %\ld be a total ( sixty-eight turns1 or ab\t "o hundr$ & five feet ( wire4 ,= /rong curr5ts ! 9-&-out wires may be atta*$ to po/s ,nos4 #a & #b at ! left1 & = weak] curr5ts to ,nos4 #b & #c4 ,= /ill weak] curr5ts1 use ,nos4 #c & #d1 & s on4 ,to detect ! v weake/ curr5ts1 atta* ! 9-&-out wires to ! fir/ & la/ po/1 & let ! curr5t travel ?r\gh all ! coils or ! entire l5g? ( ! wire w\nd ab\t ! hoop4 ,! magnetic ne$le is made 9 ! same mann] z describ$ = ,fig4 #aj1 & ! po9t] is atta*$ 9 a simil> fa%ion4 ,b in/ead ( be+ m\nt$ on a pivot ov] a c>d1 & s expos$ to ! op5 air & possible draughts1 ! delicate me*anism is arrang$ )9 a brass hoop1 :i* is made fa/ to ! l$ge4 ,! graduat$ c>d is at ! bottom ( ! hoop1 or box =m$ by x1 & to protect ! ne$le & prev5t x f be+ displac$ x %\ld be cov]$ ) glass4 ,?is c be done by mak+ a split r+ ( spr+-brass wire & press+ x d[n inside ! hoop4 ,ov] ?is a r\nd piece ( glass is plac$1 & ano!r hoop is press$ 9 above x to hold ! glass 9 position4 ,if ! r+s are c>efully made & ( /\t wire !y w /ay 9 place2 o!rwise a drop ( melt$ seal+-wax or p>aff9e w be necess>y to keep !m :]e !y are want$4 ,! glass %\ld be arrang$ close en\gh to ! ne$le to prev5t x f jump+ or be+ %ak5 (f ! support+ p91 b n s close z to prev5t its mov+ easily4 ,"p ,,ii ,*apt] ,,vii ,,electrical ,,resi/ance ,! sci5ce ( controll+ =ces is s well und]/ood & figur$ out t x becomes a simple me*anical proposition to adapt ! v>i\s types ( controll]s to any =m ( p[] t may be employ$4 ,! trem5d\s =ce /or$ )9 ! me*anism ( a great transatlantic l9] is gov]n$ by ! twi/ ( a man's wri/4 ,! locomotive t w pull a hundr$ c>s load$ ) coal1 repres5t+ a weight ( ?\s&s ( tons1 is />t$ & /opp$ by a %ort lev] t is drawn 9 "o direction or ! o!r by a man's h&4 ,great =ces ( all k9ds are q z easily controll$ z ! supply ( gas ?r\gh a jet--by simply turn+ ! key t lets out s mu* z may be requir$1 no matt] :at ! pressure is back ( ! fl[4 ,?is same pr9ciple applies to electricity1 b ! means ( gov]n+ x is va/ly diff]5t f ! me?ods employ$ = o!r =ces4 ,electricity is an unkn[n & unse5 =ce1 com+ f app>5tly n[h]e & return+ to its undiscov]$ c\ntry imm$iately ^u ! completion ( its "w4 ,! fl[ ( /eam1 wat]1 liquid air1 gas1 & compress$ air ?r\gh pipes is gov]n$ by a ?rottle or cock1 :i* all[s z mu* or z little to pass z may be requir$2 & if ! jo9ts1 unions1 & c\pl+s 9 ! pipes are n absolutely tight !re w be a leakage4 ,electricity is controll$ by resi/ance 9 its passage ?r\gh solid wires1 rods1 or b>s1 & _c be conf9$ )9 a giv5 space l wat]1 nor held 9 tanks or pipes z a vapor or gas4 ,x is invisible1 colorless1 odorless1 & occupies no app>5t space t c be measur$2 x is ! mo/ p[]ful & t]rible & yet docile =ce kn[n to man1 do+ 8 bidd+ at all times :5 prop]ly gov]n$ & regulat$4 ,9 "s respects1 electricity c be comp>$ to wat] /or$ 9 a tank--= in/ance1 if y h a tank ( wat] conta9+ fifty gallons at an elevation ( tw5ty-five feet1 & a pipe lead+ d[n f x1 ! pressure ( ! wat] at ! outlet ( ! pipe w be a giv5 numb] ( p\nds4 ,n[ if ! tank 7 d\ble ! size ! pressure at ! outlet ( ! pipe w\ld be proportionately great]4 ,n[ if y h a batt]y made up ( a numb] ( cells !y w develop a giv5 numb] ( volts1 & if ! numb] ( ! cells be d\bl$ ! voltage w be correspond+ly increas$4 ,or if y h a dynamo giv+ a c]ta9 numb] ( volts1 t numb] may be increas$ by d\bl+ ! size4 ,! wat] conta9$ )9 ! tank repres5ts its pressure at ! outlet ( ! pipe4 ,! curr5t 9 volts1 g5]at$ 9 a batt]y or dynamo1 repres5ts its pressure on an outlet or conductor wire2 & bo? repres5t ! =ce beh9d _! respective conductors4 ,! valve1 or faucet1 at ! end ( ! pipe plus ! friction 9 ! pipe w\ld repres5t ! resi/ance to ! fl[ ( wat]1 :ile ! resi/ance-coils or o!r m$iums plus ! size ( ! wire1 or conductor & swit*1 w\ld regulate ! fl[ ( electric curr5t4 ,! fl[ ( wat] 9 a pipe "u c]ta9 pressure w\ld repres5t its gallons p] m9ute or h\r1 :ile ) electricity its fl[ 9 a wire or o!r conductor w\ld repres5t its amp]age4 ,x is to gov]n ! fl[ ( curr5t t resi/+ m$iums are employ$4 ,! resi/ance ( electric curr5t is measur$ 9 ohms1 & x is ) ?is phase t we are int]e/$ 9 ?is *apt]4 ,if !re is only a small resi/ance put 9 ! pa? ( a curr5t1 !n x requires b a small pressure or voltage to s5d x ?r\gh ! wires or circuit4 ,?is is easily und]/ood by ! boy :o has exp]im5t$ ) small inc&esc5t lamps 9 :i* %ort pieces ( c>bon-filam5t are conta9$4 ,x requires ! pressure ( a few volts only to s5d ! curr5t ?r\gh ! c>bon2 b = ! l>ge c>bon-filam5ts1 measur+ t5 or twelve in*es 9 l5g?1 f "o hundr$ to five hundr$ volts may be necess>y4 ,! ord9>y h\se lamps require "o hundr$ & t5 volts & half an amp]e to give sixte5 c&le-p[]4 ,x is easily und]/ood1 !n1 t x requires a high pressure or voltage to =ce ! curr5t ?r\gh ! resi/+ c>bon-filam5t1 or across ! space f "o c>bon to ! o!r 9 ! arc-lamps us$ = /reet light+4 ,! %ort] & l>g] ! conduct+ wires ! less ! resi/ance1 & consequ5tly ! l[] ! voltage or pressure necess>y to =ce x4 ,contr>iwise ! long] & f9] ! conduct+ w>es1 ! great] ! resi/ance4 ,z copp] is ! be/ comm]cial conductor ( electric curr5ts1 x is 9 univ]sal use1 & 9 x ! m9imum ( resi/ance is (f]$ to ! curr5t4 ,iron wire is a poor] conductor1 & is n us$ = high voltage 7su* z trolleys or transmission ( p[]71 b is conf9$ to telegraph & telephone l9es & l[-pressure "w4 ,g]man-silv] wire1 "o ( ! poore/ conductors1 is n us$ = l9es at all1 b is employ$ solely z a resi/+ m$ium = controll+ curr5t4 ,ohm's ,law ,?is is ! fundam5tal =mula express+ ! relations betwe5 curr5t1 electro-motive =ce1 & resi/ance 9 an active electric circuit4 ,x may be express$ 9 sev]al ways ) ! same result1 z foll[s3 #a4 ,! curr5t /r5g? is equal to ! ,e4 ,m4 ,f4 7electro-motive =ce7 divid$ by ! resi/ance4 #b4 ,! ,e4 ,m4 ,f4 7electro-motive =ce7 is equal to ! curr5t /r5g? multipli$ by ! resi/ance4 #c4 ,! resi/ance is equal to ! ,e4 ,m4 ,f4 7electro-motive =ce7 divid$ by ! curr5t /r5g?4 ,all ^! are diff]5t =ms ( ! same /atem5t2 & :5 figur+ electrical data1 ,c /&s = curr5t1 ,e = electro-motive =ce1 & ,r = resi/ance4 ,resi/ance-coils & ,rheo/ats ,! me?od by :i* electricity is controll$ is resi/ance4 ,no matt] h[ great ! voltage ( a curr5t1 nor its volume 9 amp]es1 x c be br\ght d[n f ! deadly =ce ( ! electric trolley-curr5t to ! mild degree ne$$ to run a small fan-motor1 an electric bell1 or a m9iature lamp4 ,?is is accompli%$ by means ( resi/+ m$iums1 su* z fluids or wires1 :i* hold back ! curr5t1 & all[ only ! small quantity to pass t may be requir$ to op]ate ! app>atus4 ,! jump f ! high voltage ( ! trolley-curr5t to ! l[ "o requir$ = ! electric bell1 a lamp1 or a small motor1 is frequ5tly made 9 traction-"w1 b 9 ?is case regul> trans=m]s are us$4 ,= ! small app>atus1 t may h its curr5t suppli$ f a batt]y1 or a small dynamo driv5 by a wat]-motor1 ! =ms ( resi/ance-coils & rheo/ats describ$ on ! foll[+ pages %\ld meet e requirem5t4 ,! /&>d unit ( resi/ance is call$ an ohm1 s nam$ aft] ,dr4 ,g4 ,s4 ,ohm1 a ,g]man electrician1 ^: !ory on ! subject is accept$ z ! basis on :i* to calculate all electrical resi/ance4 ,! legal ohm is ! resi/ance ( a m]cury column "o squ>e millimetre 9 cross-sectional area & "o hundr$ & six c5timetres 9 l5g?1 & at a temp]ature ( #j ,c5tigrade or #cb ,fahr5heit1 or ! freez+-po9t = wat]4 ,! conductivity ( metals is dep5d5t greatly on _! temp]ature1 a hot wire be+ a mu* bett] conductor ?an a cold "o4 ,s9ce c\nt]-electro-motive =ce sometimes gives a spuri\s resi/ance1 ! ohmic resi/ance is ! true /&>d by :i* all curr5t is gaug$4 ,9 te*nical me*anism & close read+s ! ohmic resi/ance c\nts = a great deal1 b 9 ! simple app>atus t a boy c make ! ,g]man-silv] resi/ance coils & ! liquid resi/ance w answ] e purpose4 ,to give a cle>] idea ( ! pr9ciple ( ! rheo/ats1 a %ort description ( ! m]curial column w fir/ be pres5t$4 ,dur+ ! e>ly "p ( ! la/ c5tury wires 7 n us$ z a resi/+ m$ium = electric curr5ts4 ,9 _! place1 glass tubes1 fill$ ) m]cury seal$ at "o end & cork$ at ! o!r1 7 arrang$ 9 r[s & support$ 9 a wood5 rack4 ,illu/ration3 ,fig4 #a ,wires l$ out f ! top & bottom ( ea* tube1 & 7 br\ght d[n to metal buttons arrang$ 9 a r[ along ! front edge ( ! base-plate1 z %[n 9 ! illu/ration ( a m]curial rheo/at 7,fig4 #a74 ,ea* tube repres5t$ a c]ta9 resi/ance--"o or m ohms1 z requir$4 ,! outlet wire 0 atta*$ to ! button at "o end ( ! r[1 & ! inlet c\ld be mov$ along f button to button1 until ! requir$ am\nt ( curr5t 0 obta9$4 ,! m]curial rheo/at 0 an exp5sive1 cumb]some1 & trea*]\s ?+ to h&le2 x 0 liable to break1 & its weight (t5 prohibit$ its use 9 places :]e ! m conv5i5t & easily h&l$ ,g]man-silv] rheo/ats are n[ 9 univ]sal employm5t4 ,ov]heat+ ! m]cury 9 ! columns caus$ x to exp&1 & sometimes1 be=e ! swit* c\ld be ?r[n op51 an end w\ld be =c$ out & ! m]cury w\ld climb ov] ! edge ( ! glass columns4 ,all metals h a c]ta9 am\nt ( resi/ance = electric curr5ts1 & "s h m ?an o!rs4 ,g]man-silv]1 = in/ance--a metal made ( a mixture ( o!r metals ) ab\t eighte5 p] c5t4 ( nickel 7see ,app5dix7--is consid]$ to be ! be/ comm]cial resi/ance m$ium1 :ile pure copp] is reg>d$ z ! be/ comm]cial conductor4 ,unalloy$ copp] is univ]sally employ$ = electric conductors ( high voltage2 b = telegraph & telephone "w1 galvaniz$ iron wire is /ill us$ ext5sively4 ,! f9] ! wire1 ! high] is its resi/ance1 & ! m resi/ant ! metal1 ! great] are ! numb] ( ohms to a giv5 l5g?4 ,to n9e feet & n9e in*es ( ,no4 #cj copp] wire !re is "o ohm resi/ance1 :ile to ,no4 #bd--:i* is six sizes co>s]--!re is "o ohm to ?irty-n9e feet & "o in*4 ,9 _m cases x is necess>y to use ! co>s] wire & great] l5g?1 z ! curr5t w\ld sup]heat or burn ! f9e wire1 :ile ! co>s] w\ld conduct x safely4 ,= v high voltage & amp]age--su* z us$ 9 traction c>s1 9 p[] /ations1 & 9 manufactur+ plants--ca/+s ( ,g]man-silv] are employ$ & l9k$ 9 s]ies4 ,!y are m easily h&l$ ?an ! coils ( wire1 & a great] numb] ( !m c be accommodat$ 9 a small space4 ,illu/ration3 ,fig4 #b ,= light curr5ts 9 exp]im5tal "w1 :]e batt]ies are employ$1 obta9 a p\nd or two ( b>e ,g]man-silv] wire1 f ,nos4 #bd to #cj1 & w9d ! /r&s on a r\nd piece ( /ick atta*$ to a w9d] 7see ,magnets & ,induction-,coils1 *apt] iv474 ,make sev]al ( ^! coils1 two or ?ree in*es long1 ) ! wire w\nd closely & ev5ly4 ,:5 pull$ ap>t ! coils w appe> z %[n 9 ,fig4 #b ,a1 & w resemble a spiral spr+4 ,?is c be made fa/ ov] a porcela9 knob & ! ends caught d[n1 z %[n at ,b 9 ,fig4 #b1 or x may be drawn ov] a r\nd /ick1 a porcela9 tube1 or a lug made ( pla/] ( ,p>is & dextr9e 7?ree p>ts ( ! =m] to "o ( ! latt]71 z %[n at ,c 9 ,fig4 #b1 & ! ends securely b\nd ) a /r& or two ( wire1 twi/$ tight to keep ! ends f slipp+4 ,! lugs may be made 9 a mold1 us+ z a patt]n a piece ( broom-h&le--%ellack$ & oil$ to prev5t ! pla/] f adh]+ to x4 ,obta9 a small squ>e & deep box1 & drop "s ( ! wet mixture d[n 9 ! bottom2 on ?is place ! broom/ick1 small end d[n 7x %\ld be slightly tap]$71 & ar\nd x p\r 9 ! wet pla/] mixture4 ,:ile x is sett+1 turn ! /ick ) ! ?umb & f+]s1 s z to %ape ! hole p]fectly !n draw x out1 & a true mold w be ! result4 ,:5 dry en\gh1 p\r "s %ellac d[n into ! mold & revolve x1 s t ! %ellac w be ev5ly di/ribut$1 & let x h>d5 = a day4 ,!n saw (f ! end ( ! mold1 s t x w be op5 at bo? ends4 ,9 ord] to make ! lugs1 p\r 9 ! pla/] mixture1 tak+ c>e to oil ! mold be=e ea* p\r+1 s t ! lug c be drawn out :5 ! mixture has set4 ,if x /icks1 tap ! small end g5tly to />t x4 ,= coils :]e !re is little or no heat1 ord9>y pieces ( broom-h&le1 or r\nd /icks hav+ a coat or two ( %ellac1 w answ] v well2 b :]e ! curr5t heats ! core1 x mu/ be ( "s mat]ial t w n *>4 ,ano!r me?od ( mak+ resi/ance-coils is to measure (f a l5g? ( wire2 !n d\ble x1 & ) a small /aple atta* ! loop end at "o end ( ! 7wood57 core4 ,pay out ! two /r&s ( wire an equal di/ance ap>t ) ! ?umb & f+]s1 & ) ! o!r h& twi/ ! core4 ,at ! o!r end ( ! spool cat* ! loose ends ( ! wire "u small /aples1 tak+ great c>e n to let ! /aples t\* or ev5 be driv5 close toge!r4 ,?is arrangem5t is %[n at ,d 9 ,fig4 #b1 & = a field resi/ance-bo>d any numb] ( ^! coils may be made4 ,illu/ration3 ,fig4 #c ,9 ,fig4 #c ! mode ( connect+ coils is %[n4 ,! dots repres5t contact-po9ts to :i* ! movable arm c be %ift$4 ,! wires at ! bottom ( coil1 ,nos4 #a & #b1 are connect$ toge!r1 :ile ^? at ! top ( ,no4 #b & #c are jo9$1 & s on to ! end4 ,! lead+-9 curr5t is connect$ at pole ,h & s on to ,j1 :ile ! lead+-out wire is made fa/ to pole ,i4 ,! swit*-arm is mov$ on ! fir/ dot1 or contact-po9t1 & ! curr5t passes up wire ,a1 d[n coil ,no4 #a1 up coil ,no4 #b1 d[n ,no4 #c1 up ,no4 #d1 & s on to ,no4 #f1 & d[n wire ,g & out at ,i4 ,suppos+ t ?is (f]s too mu* resi/ance1 ! swit*-arm is mov$ up "o po9t4 ,?is cuts out coil ,no4 #a1 z ! curr5t passes up wire ,b1 ?r\gh coil ,no4 #b1 d[n ,no4 #c1 & s on1 & out ?r\gh ,g & pole ,i4 ,ano!r move ( ! swit* & coil ,no4 #b is cut out1 ! curr5t pass+ up wire ,c1 d[n coil ,no4 #c1 up ,no4 #d1 & s on1 & out at ,i4 ,ea* move ( ! swit* cuts out "o coil1 less5+ ! resi/ance2 b :5 mov$ to ! la/ contact-po9t ! curr5t fl[s )\t resi/ance--9 at ,h1 ?r\gh ! swit*-arm1 & out at ,i4 ,! plan ( arrang+ ! coils sugge/$ at ,fig4 #b ,b is %[n 9 ,fig4 #d1 :]e f\r ( ! coils are arrang$ 9 s]ies ov] porcela9 knobs1 & ! l[] ends made fa/ to ! base-bo>d ) small /aples4 ,small pieces ( brass are us$ = ! swit* contact-plates2 ^? are provid$ ) "o pla9 & "o c\nt]sunk hole = a flat & r\nd head$ screw4 ,! screw-heads are arrang$ 9 a semicircul> fa%ion1 s t ! swit*-arm1 atta*$ at "o end to ! screw ,j1 w t\* ea* plate z x is mov$ =w>d or backw>d4 ,illu/ration3 ,fig4 #d ,fig4 #e ,,two ,,simple ,,=ms ,,( ,,rheo/ats ,! curr5t pass+ 9 at b9d+-po/ ,a travels to ,j & ,b1 ! latt] be+ ! re/+-plate = ! swit*-arm4 ,a move ( ! arm to ,c s5ds ! curr5t up ov] ! fir/ coil & d[n2 !n ov] ! second1 ?ird1 & f\r? coils1 & out at ,g2 ?r\gh plate ,h 7:i* is ! re/ at ! "r side71 & out at ,i4 ,a move ( ! swit*-arm to ,d cuts out ! fir/ coil2 a move to ,e1 ! fir/ & second coils2 & s on until ! la/ plate is rea*$1 :5 ! curr5t w pass )\t resi/ance 9 at ,a1 ?r\gh ,j1 & out at ,i4 ,a simple arrangem5t = a resi/ance-coil is %[n 9 ,fig4 #e4 ,?is consi/s ( a set ( small metal plates 9 :i* two holes are made1 "o = a screw1 ! o!r = a screw-eye 7see ,b9d+-po/s1 *apt] iii474 ,two l9es ( /eel-wire nails are driv5 along a bo>d1 & ,g]man-silv] wire is drawn ar\nd !m 9 zig-zag fa%ion1 beg9n+ at ! left & go+ t[>ds ! "r side ( ! bo>d4 ,"o end ( wire is made fa/ "u ! screw-head on plate ,a4 ,! /r& is c>ri$ out ar\nd ! fir/ nail on ! l[] r[ & ov] ! fir/ "o on ! upp] r[1 !n d[n1 up1 d[n until six nails h be5 turn$4 ,! wire is !n c>ri$ d[n to ! screw 9 plate ,b1 giv5 two turns1 & c>ri$ up aga9 & ov] ! nail on ! top r[1 repeat+ ! direction ( zigzag ,no4 #a1 until six ( !m are made4 ,! end ( ! wire is !n made fa/ to plate ,g1 & all ! screws are driv5 9 to hold ! plates & wire securely4 ,! inlet wire is atta*$ to ,a1 ! outlet to ,g1 & any degree ( resi/ance c be _h by mov+ ! inlet wire to ! v>i\s plates along ! l9e1 cutt+ out sections ,nos4 #a to #f z desir$4 ,= heavi] wire ! arrangem5t z %[n 9 ,fig4 #f %\ld be satisfactory4 ,illu/ration3 ,fig4 #f ,illu/ration3 ,fig4 #g ,a frame twelve by fifte5 in*es is con/ruct$ ( wood ?ree-qu>t]s ( an in* ?ick & "o in* & a qu>t] wide1 hav+ ! ends securely fa/5$ ) glue & screws4 ,spirals are w\nd ( ,g]man-silv] wire 7any size f ,no4 #af to #bb71 & drawn ap>t4 ,! ends are caught to ! frame ) small /aples1 & ea* alt]nate coil-end is jo9$1 z %[n 9 ,fig4 #f4 ,! lead+-out wires to ! contact-po9ts on ! swit* %\ld be ( insulat$ copp]1 & are to run d[n ! sides ( ! frame1 & s to ! swit*-bo>d4 ,to cle>ly illu/rate1 h[ev]1 ! plan ( wir+1 ! draw+ is made s z to %[ ! leads f ! coil-ends to ! swit*4 ,c>e %\ld be tak5 to /udy ?is draw+ well1 s z n to make an error 9 connect+ a wrong end to a contact-po9t1 !reby caus+ a %ort circuit4 ,:5 prop]ly connect$ ! curr5t passes 9 at ,a & out at ,i2 b if wires are improp]ly connect$1 ! curr5t w jump :5 ! swit*-arm rea*es ! misconnect$ contact4 ,! swit* is an important "p ( e rheo/at1 & %\ld be c>efully & accurately made4 ,"o ( ! simple/ & mo/ practical swit*es is con/ruct$ f a %ort1 flat b> ( brass or copp] hav+ a knob atta*$ at "o end & a hole provid$ at ! o!r ?r\gh :i* a screw may pass 7see ,swit*es1 *apt] iii474 ,! contact-po9ts are made f "o or two copp] wa%]s1 ) ! holes c\nt]sunk s t a ma*9e screw ( brass1 ) a flat head1 w fit ! hole snugly4 ,! top ( ! head w !n be flu% ) ! top ( ! wa%]1 z %[n at ,fig4 #g ,a4 ,! bolt is pass$ d[n ?r\gh a piece ( bo>d1 !n slate or soap/one1 & caught ) a wa%] & nut1 z %[n at ,fig4 #g ,b4 ,a loop ( wire is pass$ ab\t ! bolt end1 !n ano!r nut is screw$ tightly ov] x to hold x 9 place1 z well z to lock ! fir/ nut4 ,! b9d+-po/s t hold ! inlet & outlet wires may be made ( bolts & nuts also1 z %[n at ,fig4 #g ,b2 b ! bolt mu/ be pass$ ?r\gh ! swit*bo>d s t ! head is at ! re> & ! ends project out to receive ! nuts4 ,a v compact & simple rheo/at & swit* is %[n 9 ,fig4 #h4 ,x is compos$ ( a base-bo>d1 eight blocks ( h>d-wood1 & a top /rip us$ z a b9d] to lock ! upp] ends ( ! blocks toge!r4 ,! h>d-wood blocks are ?ree-qu>t]s ( an in* ?ick1 "o in* & a half wide1 & f\r in*es long4 ,a small hole is made ne> ea* end ( ! block & ?r\gh "o ( !m an end ( ! wire is pass$4 ,! wire is !n w\nd r\nd ! block1 tak+ c>e to lay x on ev5ly1 & ) ab\t "o-eigh? ( an in* ( space betwe5 ea* /r&4 ,:5 ! opposite hole is rea*$1 pass ! end ( ! wire ?r\gh x & clip x4 ,! block w !n resemble ,fig4 #g ,c4 ,!re %\ld be ?ree or f\r in*es ( wire at ea* end = conv5i5ce 9 connection1 & :5 ! eight blocks are w\nd !y are to be m\nt$ on end at ! re> side ( a base-bo>d measur+ t5 in*es long1 ?ree in*es wide at ! ends1 & n9e at ! middle 7or across ! face ( ! swit*bo>d to ! re> edge beh9d ! blocks74 ,use slim /eel-wire nails & glue to atta* ! blocks to ! base2 or sl5d] screws may be employ$4 ,across ! top lay a piece ( wood a qu>t] ( an in* 9 ?ickness1 & drive small nails or screws d[n ?r\gh x & into ! blocks4 ,illu/ration3 ,fig4 #h ,fig4 #aj ,fig4 #i ,,compact ,,=ms ,,( ,,rheo/ats ,connect ! ends ( ! coils toge!r 9 s]ies1 z already describ$1 & c>ry ! wires "u ! base-plate 9 grooves cut ) a ,v-%ap$ *isel4 ,if ! sunk5 wires are bo!rsome1 ! "w may be avoid$ by runn+ ! wires direct to ! foot ( ! contact-po9ts & elevat+ ! rheo/at on f\r small blocks t may be screw$1 or nail$ & glu$1 "u ! corn]s1 z %[n 9 ,fig4 #h4 ,^! w raise ! base half an in* or m above ! table on :i* ! rheo/at w re/ s z to all[ room = ! "u wires4 ,a rheo/at ( r\nd blocks /&+ on end is %[n at ,fig4 #i ,a4 ,^! are pieces ( curta9-pole1 f\r in*es long & w\nd ) loops ( ,no4 #af or #ah wire1 z %[n at ,fig4 #i ,b4 ,! loop & loose ends are caught ) /aples1 & :5 arrang$ on a base-bo>d !y are to be connect$ 9 s]ies z be=e describ$4 ,"o long1 slim screw pass$ up ?r\gh ! base-bo>d & into ! l[] end ( ! block w hold ea* block securely 9 place4 ,to keep x f twi/+1 a little glue may be plac$ "u ! blocks s t :5 ! screw draws ! block d[n to ! base x w /ay !re p]man5tly ^u ! h>d5+ ( ! glue4 ,! lead+ wires %\ld be slipp$ "u ! wa%]s =m+ ! contact-po9ts ( ! swit*2 or !y may be c>ri$ "u ! bo>d to ! nuts t hold ! l[] ends ( ! bolts4 ,ano!r =m ( rheo/at 7,fig4 #aj ,a7 is made by saw+ a "o-in* curta9-pole into f\r-in* l5g?s & cross-cutt+ ea* piece ) eight or t5 not*es1 z %[n at ,fig4 #aj ,b4 ,^! pieces are screw$ & glu$ fa/ along ea* side ( a base-bo>d eight in*es wide & f\rte5 in*es long1 s t ! not*es face ! out] edges ( ! bo>d4 ,! /r& ( wire passes r\nd ^! upright blocks & fits into ! not*es s z to prev5t !m f fall+ d[n4 ,! top end ( wire at ea* pair ( blocks is made fa/ by a turn or two ( ano!r piece ( wire & a twi/ to hold x securely2 !n ! loose end is c>ri$ d[n ?r\gh a hole & along "u ! bo>d to ! foot ( a contact-po9t4 ,any numb] ( ^! upright coils may be made1 & on a long bo>d ! swit* may be arrang$ at "o side in/ead ( at ! end1 z %[n 9 ,fig4 #aj ,a4 ,:5 mak+ t5 or m coils x is be/ to use ?ree or f\r sizes ( wire1 beg9n+ ) f9e & end+ ) co>se4 ,= in/ance1 9 a twelve-coil rheo/at make ?ree coils ( ,no4 #bf1 ?ree ( ,no4 #bb1 & ?ree ( ,no4 #ah2 or if co>s] wire is requir$ use ,nos4 #bj1 #af1 & #ab4 ,g]man-silv] comes b>e & insulat$4 ,x is pref]able to h ! f9e wire insulat$1 b ! heavi] sizes may be b>e1 z x is *eap]2 moreov]1 if heat$ too mu* ! insulation w burn or *> (f4 ,:5 cutt+ out ! coils always beg9 at ! end :]e ! f9] wire is w\nd2 !n z ! curr5t is admitt$ m freely ! heavi] wires w conduct x )\t becom+ ov]heat$4 ,= runn+ a sew+-ma*9e1 fan1 or o!r small direct-curr5t motor w\nd = l[ voltage1 ! h\se curr5t 7if electric lights are us$ 9 ! h\se7 may be br\ght d[n to ! requir$ voltage ) ,g]man-silv] rheo/ats simil> to ^! already describ$4 ,ano!r & v simple me?od is to arrange sixte5-c&le-p[] lamps 9 s]ies1 z %[n 9 ,fig4 #aa4 ,six porcela9 lamp-sockets are screw$ fa/ to a wood base & ! lead+ 9 & out wires br\ght to b9d+-po/s or ! contact-po9ts ( a swit*4 ,! lead+-9 wire to ! s]ies is made fa/ at b9d+-po/ ,a1 :i* 9 turn is connect$ ) screw ,b1 "u ! head ( :i* ! swit*-arm is held4 ,:5 ! swit* is ?r[n ov] to contact-po9t ,c ! curr5t passes ?r\gh lamp ,no4 #a back to po9t ,d2 ?r\gh lamp ,no4 #b back to ,e2 !n ?r\gh lamps ,nos4 #c1 #d1 #e1 & #f1 & out ?r\gh po9t ,i to po/ ,j4 ,a turn ( ! swit* to ,d cuts out lamp ,no4 #a1 to ,e cuts out ,no4 #b1 & s on4 ,! filam5ts ( inc&esc5t lamps 9 _! vacuum are among ! v be/ m$iums ( resi/ance1 & ) a %ort s]ies ( lamps a curr5t ( #bbj volts c quickly be cut d[n to a few volts = light exp]im5tal "w or to run "s small piece ( app>atus4 ,illu/ration3 ,fig4 #aa ,illu/ration3 ,fig4 #ab ,illu/ration3 ,fig4 #ad ,lamps 9 s]ies are (t5 us$ to cut d[n ! curr5t = op]at+ electric toys & tra9s4 ,! adju/m5t ( ! curr5t %\ld nev] be left to *ildr51 h[ev]1 b %\ld be att5d$ to by "s "o qualifi$ to look aft] ! app>atus4 ,o!rwise an unpleasant or ev5 dang]\s %ock may be receiv$4 ,ano!r simple =m ( resi/ance app>atus is made f ! c>bon p5cils us$ = arc lights4 ,%ort pieces w answ] v well1 b if ! long b>e ones c be _h !y w be f\nd pref]able4 ,d n use ! copp]-plat$ ones z !y w\ld conduct ! curr5t too freely2 !y %\ld be b>e & black4 ,n[ ar\nd ! ends ( ea* piece take sev]al turns ( copp] wire = ! t]m9als & cut-out wires4 ,fa/5 ^? p5cils d[n on a bo>d 7z %[n at ,fig4 #ab7 by bor+ small holes ?r\gh ! bo>d1 pass+ a loop ( copp] wire d[n ?r\gh ! holes1 & giv+ ! ends a twi/ und]nea?4 ,! lead+ wires to & f ! contact-po9ts %\ld be insulat$ & may be above or bel[ ! bo>d4 ,f ! descriptions already giv51 ! connections ( ?is rheo/at c readily be und]/ood4 ,! rheo/at %[n 9 ,fig4 #ac is p]haps ! mo/ complete & practical app>atus t a boy c\ld make or w\ld ne$4 ,x is compos$ ( a frame1 six porcela9 tubes1 a swit*bo>d1 & ! necess>y ,g]man-silv] & copp] wire4 ,f an electrical supply-h\se obta9 six porcela9 tubes f\rte5 by ?ree-qu>t] in*4 ,porcela9 tubes & rods w>p 9 ! fir+ & are seldom /raight2 9 pur*as+ ^! select !m z ne>ly p]fect z possible 9 %ape1 size1 & l5g?4 ,illu/ration3 ,fig4 #ac ,a ,,panel ,,rheo/at ,buy1 also1 twelve small porcela9 knobs t are ! "r size to fit inside ! l>ge tubes4 ,^! %\ld h holes bor$ ?r\gh !m to admit screws4 ,con/ruct a frame ( h>d-wood to accommodate ! tubes1 z %[n 9 ! draw+1 & leave "o end loose4 ,) slim screws make ! porcela9 knobs fa/ to ! top & bottom /rips ( ! frame1 z %[n 9 ,fig4 #ad4 ,! porcela9 rods w fit ov] ^! & w ?us be held securely 9 ! frame1 "o small knob ent]+ ! tube at ea* end1 z indicat$ by ! dott$ l9es 9 ,fig4 #ad4 ,! fir/ porcela9 tube to ! left is w\nd ) ,no4 #bb ,g]man-silv] wire1 ! next ) ,no4 #bj1 ! ?ird ) ,no4 #ah1 !n ,nos4 #af1 #ad1 & #ab2 s t 9 ?is field a broad range c be _h = a curr5t ( #aaj volts4 ,! coils are connect$ 9 s]ies1 z expla9$ = ! o!r rheo/ats1 & ! lead+ wires br\ght d[n to ! back ( a swit*bo>d ( :i* ,fig4 #ac ,a is ! front & ,fig4 #ac ,b ! re> view4 ,! swit*bo>d is made ( ?9 slate or soap/one2 or a fibre-bo>d may be employ$4 ,fibre-bo>d is especially made = electrical "w1 & c be _h f a l>ge supply-h\se 9 pieces ( v>i\s ?ickness1 ?ree-eigh?s ( an in* be+ ab\t "r = ?is bo>d4 ,brass bolts & nuts & copp] wa%]s are us$ = ! contact-poles1 & :5 ! ends ( ! lead+ wires are loop$ ar\nd ! bolts ! nuts are to be screw$ d[n tightly s z to make good contacts4 ,?is rheo/at may be us$ :5 ly+ on a table1 or x c be hung up by means ( two screw-eyes driv5 9 ! top ( ! frame1 z %[n 9 ,fig4 #ac ,a4 ,a conv5i5t =m ( rheo/at = f9e wire & high resi/ance is %[n 9 ,fig4 #ae4 ,?is is on ! plan ( ! well-kn[n ,:eat/one rheo/at & does n require a swit*bo>d nor a s]ies ( coils4 ,two roll]s1 "o ( wood ! o!r ( metal or brass-cov]$ wood1 are set 9 a frame1 & by means ( a h&le & project+ ends ) squ>e %\ld]s1 "o or ! o!r ( ! roll]s may be turn$ s t ! wire on "o w9ds up :ile on ! o!r x unw9ds4 ,! wood5 roll] may be made f a piece ( curta9-rod "o in* 9 diamet]1 & x %\ld h a ?read cut on x4 ,?is w h to be done on a screw-cutt+ la!1 & any ma*9i/ w d x = a few c5ts4 ,!re %\ld be f twelve to sixte5 ?reads to ! in*--no m--al?\gh !re may be z few z eight4 ,twelve w be f\nd a good numb]1 z t does n cr[d ! coils & ! risk ( _! t\*+ is m9imiz$4 ,! ends ( ! roll] %\ld h be>+s t w fit 9 holes made 9 ! end-pieces ( ! frame1 & at "o end ( ea* roll] a squ>e %\ld] is to be cut1 z %[n at ,a 9 ,fig4 #af4 ,a %ort h&le may be made f two small pieces ( wood1 z %[n at ,b 9 ,fig4 #af4 ,x mu/ be provid$ ) a squ>e hole s t x w fit on ! roll] ends4 ,! metal roll] may be made f a piece ( light brass tub+ "o in* 9 diamet] ?r\gh :i* a wood5 core is slipp$2 or x c be a piece ( brass-cov]$ curta9-pole ) ! ends %ap$ ! same z ! wood5 "o4 ,! wood roll] %\ld h a coll> ( ?9 brass or copp] 7or o!r s(t metal except lead7 atta*$ to ! front end2 or sev]al turns ( wire may be made ab\t ! roll] s z to =m a contact-po9t4 ,a piece ( spr+ brass1 copp]1 or t9 re/s on ?is coll> & is held fa/ "u a b9d+-po/1 :i* 9 turn is screw$ to ! wood5 frame4 ,a simil> /rip ( spr+ metal is held "u ano!r po/ on ! opposite side ( ! frame & be>s on ! metal roll]4 ,illu/ration3 ,fig4 #ae ,illu/ration3 ,fig4 #af ,g]man-silv] wire is w\nd on ! wood5 roll]1 "o end hav+ be5 made fa/ to ! metal coll>2 & :5 all ! ?read grooves on ! wood roll] are fill$ ! opposite end ( ! wire is atta*$ to ! re> end ( ! metal roll]4 ,! curr5t ent]+ at b9d+-po/ ,no4 #a crosses on ! /rip ( spr+ metal to ! coll>1 travels along ! coil ( wire1 & crosses to ! metal roll] & is conduct$ out at b9d+-po/ ,no4 #b 7see ,fig4 #ae74 ,if ! resi/ance is too great slip ! h&le ov] ! end ( ! metal roll] & give x sev]al turns4 ,! curr5t w !n pass ) great] fre$om z ! wire on ! wood5 roll] becomes %ort]4 ,?is may be readily se5 by connect+ a small lamp 9 s]ies ) a batt]y & ?is rheo/at4 ,z ! metal cyl9d] is turn$ ! curr5t fl[s m freely & ! filam5t becomes r$1 !n :ite1 & f9ally burns to its full capacity4 ,take c>e1 h[ev]1 n to admit too mu* curr5t z x w burn out ! lamp4 ,"s sort ( adju/m5t %\ld be made to prev5t ! roll]s turn+ ( !mselves & ?us all[+ ! wire coils to slack54 ,?is may be done by bor+ ! two holes = ! roll]s to fit 9 & !n1 ) a key-hole saw1 cutt+ ! /ick z %[n at ,c 9 ,fig4 #af1 tak+ c>e n to split x at ! ends4 ,! result w be a long slot :i*1 h[ev]1 has no?+ to d ) ! be>+s4 ,d[n ?r\gh ! middle ( ! /ick make a hole ) an awl1 s t ! screw-eye w move easily 9 ! upp] half b w hold 9 ! l[] half4 ,"u ! head ( ! eye place a small copp] wa%]2 !n ) ! ?umb & f+] drive ! screw-eye d[n until ! head re/s on ! wa%]4 ,a slight turn ( ! eye :5 x is 9 ! "r place w draw ! upp] & l[] p>ts ( ! /ick toge!r & b9d ! wood ab\t ! be>+ ends ( ! roll]s4 ,! roll]s %\ld n be held too tightly z t w\ld /ra9 ! wire :5 w9d+ x f "o to ! o!r4 ,x %\ld be j tight en\gh to keep ! wire taut4 ,two or m ( ^! roll] resi/ance-frames may be made & connect$ 9 s]ies s t a close adju/m5t c be _h :5 us+ batt]y curr5ts = exp]im5t+4 ,liquid ,resi/ance ,ap>t f metallic1 m]curial1 or c>bon resi/ance a =m ( liquid app>atus is frequ5tly us$ 9 laboratory & light exp]im5tal "w4 ,illu/ration3 ,fig4 #ag ,illu/ration3 ,fig4 #ai ,?is /yle ( resi/ance equipm5t is ! lea/ exp5sive to make1 & w give excell5t satisfaction to ! boy :o is us+ light curr5ts = induction-coils1 lamps1 galvanomet]s1 & te/+ 9 g5]al4 ,! simple/ =m ( liquid resi/ance is made by us+ a glass bottle ) ! upp] "p cut away4 ,! cutt+ may be done ) a /eel-:eel glass-cutt]4 ,! bottle %\ld !n be tapp$ on ! cut l9e until ! top "p falls away4 ,g ov] ! %>p edges ) an old file to *afe ! edge & r\nd x2 !n sold] a t91 copp]1 or brass disk to a piece ( well-insulat$ wire & drop x d[n 9 ! bottom ( ! receptacle1 z %[n at ,fig4 #ag4 ,cut a small] disk ( metal1 or use a brass button1 & susp5d x on a copp] wire :i* passes ?r\gh a small hole 9 a piece ( wood at ! top ( ! j>4 ,not*es %\ld be cut at ! "u side ( ?is wood cross-piece s t x w fit on top ( ! j> & /ay 9 place4 ,! j> is to be ne>ly fill$ ) wat]1 hav+ a teaspoonful ( sulphate ( copp] dissolv$ 9 x4 ,?is w turn ! wat] a blui% color & make x a slightly bett] conductor1 p>ticul>ly :5 ! button is l[]$ close to ! r\nd disk4 ,if a high resi/ance is desir$ ! copp] may be omitt$ leav+ ! wat] 9 its pure /ate4 ,! wires lead+ 9 & out ( ! j> %\ld be connect$ betwe5 ! app>atus & ! batt]y s t ! prop] amp]age c be _h by rais+ or l[]+ ! button4 ,a s]ies ( ^! liquid resi/ance-j>s may be made ( glass tubes an in* 9 diamet] & twelve in*es long4 ,"o end ( !m may be /opp$ ) a cem5t made ( pla/] ( ,p>is six p>ts1 gr\nd silex or f9e :ite s& two p>ts1 & dextr9e two p>ts4 ,mix ! +r$i5ts toge!r :5 dry1 tak+ c>e to break all small lumps 9 ! dextr9e2 !n add wat] until x is ( a ?ick consi/5cy l s(t putty4 ,sold] ! ends ( "s copp] wires to disks ( copp] or brass & set !m on ! middle ( bone-buttons2 ^! 9 turn are to be imb$d$ 9 ! mixture aft] ! wire has be5 pass$ ?r\gh a hole 9 ! bottom4 ,_! location c be se5 9 ! bottom ( ! tubes ,fig4 #ah1 & ,fig4 #ai ,a is an enl>g$ figure draw+ ( ! plate1 button1 & wire4 ,! wires are br\ght out "u ! l[] edge ( ! tubes1 & en\gh ( ! composition is float$ ab\t ! bottom & out] edge ( ! tube to =m a base1 z %[n 9 ! draw+4 ,a base-bo>d is made six in*es wide & long en\gh to accommodate ! desir$ numb] ( tubes4 ,two pieces ( wood "o in* wide & ?ree-qu>t]s ( an in* ?ick h holl[ not*es cut f !m at "o side1 z %[n at ,fig4 #ai ,b4 ,9 ^! not*es ! tubes are gripp$4 ,screws are pass$ ?r\gh "o /ick & into ! o!r s z to clamp ! wood & tubes securely toge!r4 ,! re> /ick is support$ on two uprights :i* are made fa/ to ! re> edge ( ! base-plate ) screws & glue4 ,along ! front ( ! base-bo>d small metal contact plates1 or b9d+-po/s1 are arrang$ 7see ,b9d+-po/s1 *apt] iii47 & ! wires l$ to !m f ! tubes1 z %[n 9 ! draw+4 ,! top or drop wires 9 ! tubes are provid$ ) metal buttons at ! ends2 or ! end ( ! wire may be roll$ up s z to =m a little knob4 ,! mann] ( connect+ ! wires 0 freely expla9$ 9 ! resi/ance-coil descriptions & may be /udi$ out by exam9+ ! draw+ closely4 ,9 ?is resi/ance-app>atus !re are two ways ( cutt+ out a m$ium--fir/1 by l[]+ ! wire 9 ! tube s t bo? contact-po9ts meet2 & second1 by cutt+ out ! fir/ tube altoge!r by connect+ ! incom+ wire ) ! second b9d+-po/4 ,!n aga9 ! resi/ance may be regulat$ q accurately by rais+ or l[]+ ! wires 9 ! liquid4 ,= example1 !re is too mu* resi/ance if ! curr5t has to travel ?r\gh all ! tubes4 ,if x is too /rong :5 "o tube is cut out1 ! wire 9 tube ,no4 #a is l[]$ s t ! contacts are an in* ap>t4 ,!n ! m accurate adju/m5t is made by dropp+ ! wire 9 ! second tube1 z %[n 9 ,fig4 #ah4 ,! wires lead+ out at ! top ( ! tubes are p9*$ ov] ! edge to hold !m 9 place4 ,!y %\ld be cotton insulat$ & ! "p t is 9 ! liquid %\ld be coat$ ) hot p>aff9e4 ,! wat] may be made a slightly bett] conductor if a small portion ( sulphate ( z9c1 or sulphate ( copp]1 is add$ to ea* tubeful4 ,illu/ration3 ,fig4 #ah ,hittorf's resi/ance-tube is "o ( ! olde/ on ^! l9es1 & two or m ( !m are c\pl$ 9 s]ies1 z describ$ = ?is wat]-tube resi/ance2 glass tubes are employ$ t h "o end seal$ ) a p]man5t composition1 z describ$ = ,fig4 #ah4 ,a metallic cadmium electrode is plac$ at ! bottom ( ! tube1 & ! tube is !n fill$ ) a solution ( cadmium iodide "o "p & amylic alcohol n9e p>ts1 & !n cork$4 ,a wire pass+ d[n ?r\gh or at ! side ( ! cork is atta*$ to ano!r small piece ( metallic cadmium1 :i* t\*es ! top ( or is susp5d$ a %ort di/ance 9 ! liquid4 ,z ! alcohol is volatile ! cork _c be left out ( ! tube1 & ! wire mu/ be drawn ?r\gh ! cork ) a ne$le s t no op5+ is left = evaporation4 ,a numb] ( ^! tubes may be made & c\pl$ 9 s]ies & ! wires l$ d[n to ! contact-po9ts ( a swit*4 ,*apt] ,,viii ,,! ,,telephone ,= direct communication ov] %ort or mod]ately long di/ances1 no?+ has be5 inv5t$ z yet t w take ! place ( ! telephone4 ,a few ye>s ago1 :5 ?is in/rum5t 0 fir/ br\ght out1 x 0 ! wond] ( ! times1 j z wireless telegraphy is to-day4 ,/>t+ ) ! simple =m ( ! two cups ) membranes across ! ends1 & a /r+ or a wire connect+ !m1 we h to-day ! complex & wond]ful electric telephone1 giv+ p]fect s]vice up to a di/ance ( two ?\s& miles4 ,"s day inv5tors 9 ! sci5ce ( telephony w make x possible to communicate across or "u ! oceans1 & :5 ! boys ( to-day gr[ to manhood !y %\ld be able to transact bus9ess by 'phone f ,san ,francisco to ! ,f> ,ea/1 or f ! cities ne> ! ,atlantic coa/ to ,london1 ,p>is1 or ,b]l94 ,x is h>dly necess>y to ent] into ! hi/ory ( telephones1 z ?is in=mation may be readily f\nd 9 any mod]n encyclopdia or ref]5ce "w4 ,b ! boy :o is int]e/$ 9 electricity wants to "k h[ to make a telephone1 & h[ to d x 9 ! up-to-date way1 ) ! wire & gr\nd l9es1 swit*es1 cut-outs1 bell connections1 & o!r vital p>ts1 prop]ly con/ruct$ & assembl$4 ,9 ?is laudable ambition we w endeavor to help him4 ,! g5]al pr9ciple ( ! telephone may be expla9$ 9 ! /atem5t t x is an app>atus = ! conveyance ( ! human voice1 or inde$ any s\nds :i* are ! direct result ( vibration4 ,s\nd is due to ! vibrations ( matt]4 ,a piano /r+ produces s\nd because ( its vibration :5 /ruck1 or pull$ to "o side & !n releas$4 ,?is vibration sets ! air 9 rapid motion1 & ! result is ! record+ ( ! s\nd on our e>-drums1 ! latt] correspond+ to ! film ( %eepsk9 or bladd] drawn ov] ! holl[ cup or cyl9d] ( a toy telephone4 ,:5 ! head ( a drum is /ruck ) a small /ick x vibrates4 ,9 ?is case ! vibrations are set 9 motion by ! bl[1 :ile 9 ! telephone a simil> ph5om5on is ! result ( vibratory waves fall+ f ! voice on ! ?9 membrane1 or disk ( metal1 9 ! transmitt]4 ,:5 ^! vibrations rea* ! e>-drum ! n]v\s sy/em1 correspond+ to electricity 9 ! me*anical telephone1 c>ries ?is s\nd to our bra9s1 :]e x is record$ & und]/ood4 ,9 ! telephone ! wire1 *>g$ ) electricity1 c>ries ! s\nd f "o place to ano!r1 ?r\gh ! ag5cies ( magnetism & vibration4 ,ov] %ort di/ances1 h[ev]1 magnetism & electricity ne$ n be employ$ = ! transmission ( s\nd4 ,a %ort-l9e telephone may be built on purely vibratory pr9ciples4 ,almo/ e boy has made a 8phone0 ) two tomato-cans ov] :i* a membrane is drawn at "o end & ti$4 ,! middle ( ! membrane is punctur$1 & a button1 or o!r small1 flat object1 is arrang$ 9 connection ) ! wires t lead f c to c4 ,a ,bladd] ,telephone ,a really practical talk+ app>atus ( ?is simple nature may be made f two fre% beef bladd]s obta9$ f a slaught]-h\se or f ! but*]4 ,y w also ne$ two bo>ds ) holes cut 9 !m1 two buttons1 "s tacks1 & a l5g? ( f9e1 h>d1 brass1 copp]1 or t9n$ iron wire4 ,! size %\ld be ,no4 #bb or ,no4 #bd4 ,! bo>ds %\ld be t5 by f\rte5 in*es & half an in* 9 ?ickness4 ,cut holes 9 !m eight in*es 9 diamet]1 hav+ fir/ /ruck a circle ) a compass4 ,?is may be done ) a keyhole saw & ! edges s&-pap]$ to remove r\gh places4 ,prep>e ! bladd]s by bl[+ !m up & tie+ !m4 ,leave !m inflat$ = a day or two until !y h /ret*$1 b d n let !m get h>d or dry4 ,:5 ! bladd]s are ready1 cut (f ! necks1 & also remove ab\t "o-?ird ( ! mat]ial1 measur+ f end to end4 ,soak ! bladd]s 9 w>m wat] until !y become s(t & :ite4 ,/ret* !m1 loosely b ev5ly1 ov] ! op5+ 9 ! bo>ds1 lett+ ! inside ( ! bladd] be on top1 & tack !m tempor>ily all ar\nd1 "o in* f ! edge ( ! op5+4 ,te/ = ev5ness by pu%+ d[n ! bladd] at ! middle4 ,if x /ret*es smoo?ly & )\t wr9kles x w d2 o!rwise ! position & tacks mu/ be *ang$ until x sets p]fectly smoo?4 ,illu/ration3 ,fig4 #a ,illu/ration3 ,fig4 #b ,illu/ration3 ,fig4 #c ,illu/ration3 ,fig4 #d ,! bladd] mu/ n[ be p]man5tly fa/5$ to ! bo>d by means ( a lea!r b& half an in* wide & tacks driv5 closely1 z %[n 9 ,fig4 #a4 ,) a %>p knife trim away ! r\gh edges ( ! bladd] t ext5d beyond ! circle ( lea!r4 ,atta* a piece ( ! f9e wire to a button1 z %[n 9 ,fig4 #b1 & pass ! free end ?r\gh ! c5tre ( ! bladd] until ! button re/s on its surface4 ,!n fa/5 an eight-p\nd weight to ! end ( ! wire & set 9 ! sun = a few h\rs1 until ?or\ghly dry1 z %[n at ,fig4 #c4 ,:5 bo? drums are complete1 place "o at ea* end ( a l9e1 & connect ! %ort wires ) ! long wire1 draw+ ! latt] q taut4 ,! c\rse ( ! ma9 wire %\ld be z /raight z possible1 & %\ld x be too long x may be support$ by /r+ loops fa/5$ to ! limbs ( trees1 or susp5d$ f ! cross-piece ( supports made 9 ! =m ( a gall[s-tree or lett] ,f4 ,to communicate x w be necess>y to tap on ! button ) a lead-p5cil or small h>d-wood /ick4 ,! vibration w be he>d at ! o!r end ( ! l9e & w attract att5tion4 ,by speak+ close to ! bladd] 9 a cle>1 di/9ct tone1 ! s\nd w c>ry = at lea/ a qu>t] ( a mile1 & ! return vibrations ( ! voice at ! o!r end ( ! l9e c be cle>ly recogniz$4 ,a ,s+le 7,receiv]7 ,l9e ,! pr9cipal p>ts ( ! mod]n telephone app>atus are ! transmitt]1 receiv]1 induction-coil1 signal-bell1 pu%-button1 batt]ies1 & swit*4 ,! boxes1 wall-plates1 etc41 etc41 are b accessories to :i* ! active p>ts are atta*$4 ,! fir/ telephone t came into g5]al use 0 ! inv5tion ( ,graham ,bell1 & ! pr9ciple ( 8 receiv] has n be5 mat]ially *ang$ f t day to ?is1 except t n[ a d\ble-pole magnet & two f9e wire coils are employ$ 9 place ( ! s+le magnet & "o coil4 ,a practical =m ( s+le magnet receiv] t any boy c easily con/ruct is %[n 9 ,fig4 #d1 & ,fig4 #e is a sectional draw+ ( ! receiv] drawn z ?\gh x _h be5 slic$ or saw$ 9 two1 f front to re>4 ,x is made f a piece ( curta9-pole "o in* & an eigh? 9 diamet] & ?ree in*es & a half long4 ,a hole ?ree-eigh?s ( an in* 9 diamet] is bor$ its entire l5g? at ! middle1 & ?r\gh ?is ! magnet passes4 ,at "o end ( ?is tube a wood5 pill-box 7,e7 is made fa/ ) glue1 or a wood5 cup may be turn$ out on a la! & atta*$ to ! magnet tube4 ,if ! pill-box is employ$ x %\ld be two in*es & a half 9 diamet]1 & at f\r equidi/ant places inside ! box small lugs ( wood are to be glu$ fa/4 ,into ^! lugs ! screws employ$ to hold ! cap are driv54 ,! walls ( pill-boxes are s ?9 t )\t ^! lugs ! cap c\ld n be fa/5$ ov] ! ?9 disk ( metal 7,d7 unless x 7 ti$ or wir$ on1 & t w\ld n look well4 ,if ! cup is turn$ ! walls %\ld be left ?ick en\gh to pass ! screws into1 & ! inside diamet] %\ld !n be "o in* & ?ree-qu>t]s4 ,illu/ration3 ,fig4 #e ,illu/ration3 ,fig4 #f ,! cap 7,b7 is made f ?9 wood1 fibre1 or h>d rubb]4 ,x is provid$ ) a ?9 rim or coll> to sep>ate its inn] side f ! face ( ! disk 7,d74 ,f\r small holes are bor$ ne> ! edge ( ?is cap1 s t ! screws :i* hold x fa/ to ! cup 7,e7 may pass ?r\gh !m4 ,! magnet 7,m7 is a piece ( h>d /eel ?ree-eigh?s ( an in* 9 diamet] & f\r in*es & a qu>t] long4 ,?is may be pur*as$ at a supply-h\se1 & if x is n h>d en\gh a blacksmi? c make x s by heat+ & plung+ x 9 cold wat] sev]al times4 ,x may be magnetiz$ by rubb+ x ov] ! surface ( a l>ge horse%oe magnet1 or if y live ne> a p[] /ation y c get "o ( ! workm5 to magnetize x = y at a trifl+ co/4 ,%\ld y happ5 to possess a b> magnet ( s(t iron ) a numb] ( coils ( wire1 & also a /orage-batt]y1 ! /eel b> may be sub/itut$ = ! s(t iron core & ! curr5t turn$ on4 ,aft] five m9utes ! /eel c be )drawn4 ,x is n[ a magnet1 & w hold its magnetism indef9itely4 ,n[ h a ?91 flat spool turn$ f maple or boxwood to fit ov] "o end ( ! rod1 & w9d x ) a numb] ( lay]s ( ,no4 #cf copp] wire insulat$ ) silk4 ,?is is kn[n 9 ! electrical supply-h\ses z 8phone0-receiv] insulat$ wire1 & w co/ ab\t fifty c5ts an ounce4 ,"o ounce w be en\gh = two receiv]s4 ,x %\ld be w\nd ev5ly & smoo?ly1 l ! /r&s ( ?read on a spool1 & ?is may be done ) ! aid ( ! w9d] describ$ on page #eh4 ,:5 ! wire is 9 place a drop ( hot p>aff9e w hold ! end s t ! wire w n unw9d4 ,! ends ( ?is spool-w9d+ %\ld be made fa/ to heavi] wires1 :i* are run ?r\gh small holes 9 ! tube 7,a7 & project out at ! end1 z %[n at ,f ,f4 ,! magnet1 ) its wire-w\nd spool on ! end1 is !n pu%$ ?r\gh ! hole 9 ,a until ! top end ( ! rod is slightly bel[ ! edges ( ! cup 7,e71 s t :5 ! metal disk 7,d7 is laid ov] ! cup 7,e7 ! space betwe5 ! magnet & disk1 or diaphragm 7,d71 is "o-sixte5? ( an in* 7see ,fig4 #e74 ,put "s %ellac on ! magnet1 s t :5 x is 9 ! "r place ! %ellac w dry & hold x fa/4 ,! cap 7,b7 holds ! disk 7,d7 9 place1 & protects ! spool & its f9e wire f be+ damag$ & f collect+ du/4 ,aft] giv+ ! ext]ior a coat ( black pa9t & a f9i%+ coat or two ( %ellac1 ! receiv] w be ready = use4 ,! orig9al telephone app>atus 0 made up ( ^! receiv]s only--"o at ea* ( a l9e 9 connection ) a batt]y1 bell1 pu%-button1 & swit*4 ,on a w9d[-cas+1 or ! wall ?r\gh :i* ! wires pass$1 a lightn+-arre/] 0 arrang$ & made fa/4 ,us+ receiv]s only1 x 0 necess>y to speak ?r\gh ! same in/rum5t t "o he>d ?r\gh1 & = a few ye>s ?is unh&y me?od ( communication 0 ! only "o possible4 ,!n ! transmitt] 0 inv5t$4 ,plan ( ,in/allation ,_m ( ^! s+le-receiv] l9es are /ill 9 use1 & z !y require b a small am\nt ( con/ructive skill a diagram ( ! wir+ & ! plan ( arrangem5t is %[n 9 ,fig4 #f4 ,at ! left side1 ,r is ! receiv] at "o end ( ! l9e & ,r #b t at ! o!r1 l9e ,no4 #a be+ a cont9u\s wire betwe5 ! two receiv]s4 ,:5 ! boy at ,r wi%es to call 8 fri5d at ,r #b he uses 8 pu%-button 7,p ,b71 & ! batt]y 7,b ,b7 op]ates ! electric bell 7,e ,b #b7 at ! o!r end4 ,9 ord] to h ! bell connections op]ative1 ! swit* 7,s #b7 mu/ be ?r[n ov] to ! left :5 ! l9e is 8quiet10 :ile ! swit* 7,s7 %\ld be ?r[n to ! "r4 ,) ! swit*es 9 ?is position ! boy at ei!r end may call 8 fri5d at ! opposite end4 ,) ! swit* 7,s #b7 ?r[n to ! left 7! position x %\ld be 91 except :5 talk+ ov] ! l9e71 ! boy at ! o!r end pu%es 8 button 7,p ,b71 fir/ ?r[+ swit* ,s to ! left4 ,?is makes connection = ! batt]y 7,b ,b71 & ! circuit is clos$ ?r\gh wires t jo9 l9e ,no4 #a & l9e ,no4 #b at #a & #b4 ,! bran* l9es to ! bell 7,e ,b #b7 jo9 ! ma9 l9es at #c & #d1 ?r\gh swit* ,s #b1 :5 ! b> is ?r[n to ! left4 ,! circuit be+ complete1 ! batt]ies 7,b ,b7 at "o end ( ! l9e r+ ! bell 7,e ,b #b7 at ! o!r end ( ! l9e4 ,9 ! rev]se mann]1 :5 ! swit* 7,s7 is ?r[n to ! "r1 ! boy at ! opposite end r+s ! bell 7,e ,b7 by press+ on ! button 7,p ,b #b71 fir/ ?r[+ swit* ,s #b ov] to ! "r4 ,if ! boy at ! left is call+ up ! boy at ! "r1 ! swit* 7,s7 %\ld be ?r[n to ! left1 & he keeps r++ until ! o!r op]ator ?r[s swit* ,s #b ov] to ! "r4 ,if n[ he has ! receiv] 7,r7 up to 8 e> he c he> ! vibration ( ! bell 7,e ,b #b7 r++ ?r\gh ! receiv] 7,r7 at 8 end ( ! l9e4 ,b :5 ! boy summon$ to ,r #b takes up ! receiv] & places x to 8 e>1 he ?r[s swit* ,s #b ov] to ! "r side1 & ! boy at ,r leaves swit* ,s ov] on ! left side4 ,?is br+s ! l9es into direct connection ) ! receiv]s 9 s]ies4 ,be c>eful1 :5 sett+ up ?is l9e1 to h ! batt]ies 7,b ,b7 9 s]ies ) ,b #b ,b #b2 o!rwise !re w\ld be c\nt]-action4 ,! c>bon ( "o cell %\ld be connect$ ) ! z9c ( ! next cell1 & s on4 ,ano!r receiv] is %[n at ,fig4 #g4 ,! tube 7,a7 & ! cup are turn$ f "o piece ( wood1 & ! cap 7,b7 f ano!r piece4 ,! l5g? ( ! receiv] is five in*es1 & ! cap is two in*es & a half across4 ,! %ank1 or h&le1 ?r\gh :i* ! magnet is pass$ measures "o in* & a qu>t] 9 diamet]4 ,^! wood p>ts w h to be made by a wood-turn]2 & be=e ! long piece is put 9 a la! ! hole1 ?ree-eigh?s ( an in* 9 diamet]1 %\ld be bor$4 ,x mu/ be done c>efully1 s t ! wood %ell w be ( ev5 ?ickness all ar\nd ! hole4 ,also two small holes %\ld be made ! entire l5g? ( ! h&le1 ?r\gh :i* ! wires lead+ f ! coil to ! b9d+-po/s may pass4 ,illu/ration3 ,fig4 #g ,! spool = ! f9e insulat$ wire coil is turn$ f box-wood or maple1 & w\nd z describ$ 9 *apt] iv41 on ,magnets & ,induction-coils4 ,small b9d+-po/s 7,f ,f7 ) screw ends %\ld be driv5 d[n into ! holes at ! end ( ! h&le & ov] ! b>e ends ( ! wires t project out ( ! holes4 ,! magnet 7,m7 is ?ree-eigh?s ( an in* 9 diamet]1 & is provid$ ) ! spool & coil 7,c7 at ! l>ge end ( ! receiv]4 ,! disk 7,d7 is ( v ?9 iron1 & is held 9 place by ! cap 7,b7 & f\r small brass screws driv5 ?r\gh ! edge ( ,b & into ! cup end ( ,a4 ,a screw-eye %\ld be driv5 into ! small end ( ! receiv] f :i* x may hang f a hook4 ,if a d\ble hook & b> is employ$ ! receiv] w hang 9 ! =k1 be+ held !re by ! rim ( wood turn$ at ! small end ( ,a4 ,a ,d\ble-pole ,receiv] ,illu/ration3 ,fig4 #h ,ano!r =m ( receiv] is %[n at ,fig4 #h4 ,?is is a d\ble-pole receiv]1 ) ! coils ( f9e wire arrang$ on ! ends ( a b5t b& ( /eel & locat$ 9 ! cup 7,a71 s t ! ends ( ! magnet are close to ! diaphragm 7,d74 ,fig4 #h is a sectional view ( an assembl$ receiv]1 b a good idea c be _h f ! draw+s ( ! sep>ate p>ts4 ,! magnet 7,m7 is ( /eel "o-eigh? ( an in* ?ick & five-eigh?s ( an in* wide4 ,a blacksmi? w make ?is at a small co/4 ,x %\ld measure two & "o-half in*es wide1 two & "o-half in*es long1 ! ends be+ five-eigh?s ( an in* ap>t4 ,?9 wood5 spools are made f wood or fibre to fit ov] ! /eel ends1 & are w\nd ) ,no4 #cf silk-insulat$ wire4 ,a wood5 cup1 or %ell 7,a71 is turn$ f *]ry1 maple1 or o!r close-gra9$ wood1 & at ! back a hole is cut j l>ge en\gh = ! magnet ends to slip ?r\gh exclusive ( ! coils w\nd on !m4 ,a plug ( wood 7,a ,a7 is driv5 betwe5 ! ends ( ! magnet to hold !m 9 place4 ,"s %ellac on ! edges ( ! hole & ! plug w h>d5 & keep ! p>ts 9 place4 ,! coils 7,c ,c7 are plac$ on ! magnet ends1 & ! f9e wires are made fa/ to ! b9d+-po/s 7,e ,e71 ! latt] be+ screw$ fa/ to ! %ell 7,a74 ,! diaphragm 7,d7 is !n arrang$ 9 place & held ) ! cap 7,b7 & ! small screws :i* pass ?r\gh x & into ! %ell 7,a74 ,! ,transmitt] ,) any "o ( ^! receiv]s a m complete & conv5i5t telephone c be made by ! addition ( a transmitt] & an induction-coil4 ,foll[+ ! inv5tion ( ! receiv]1 sev]al transmitt]s 7 design$ & pat5t$1 among !m be+ ! ,edison1 ,blake1 ,clamond1 ,we/]n ,union1 & ,hunn+4 ,! ,edison & ,hunn+ are ! ones 9 g5]al use1 & z ei!r ( !m c easily be made by a boy a simplifi$ type ( bo? is %[n 9 ,figs4 #i & #aa4 ,illu/ration3 ,,fig4 #i ,,fig4 #aj ,,fig4 #aa ,,fig4 #ab ,,simplifi$ ,,type ,,( ,,transmitt] ,"s small blocks ( wood1 t9 funnels1 small screws1 granulat$ or p[d]$ c>bon1 "s ?9 pieces ( flat c>bon1 & a piece ( v ?9 f]rotype plate w be ! pr9cipal ?+s ne$$ 9 mak+ a transmitt] simil> to ! "o %[n 9 ,fig4 #i4 ,all t is visible f ! outside is a plate ( wood screw$ to a block ( wood1 & a m\?-piece made fa/ to ! ?9 bo>d4 ,9 ,fig4 #aj an int]ior section is %[n1 :i* :5 once und]/ood w be f\nd extremely simple4 ,! block 7,a7 is ( p9e1 :ite-wood1 bir*1 or *]ry1 & is two in*es & ?ree-qu>t]s squ>e & five-eigh?s or ?ree-qu>t]s ( an in* ?ick4 ,a hole sev5-eigh?s ( an in* 9 diamet] is bor$ 9 ! c5tre ( ?is block1 half an in* deep1 & a pa? is cut at ! face ( ! block "o in* & a half 9 diamet] & "o-eigh? ( an in* deep4 ,be c>eful to cut ^! holes accurately & smoo?ly1 & if x is n possible to d s1 x w\ld be well to h !m put 9 a la! & turn$ out4 ,! face-plate 7,b7 is two in*es squ>e1 ) a ?ree-qu>t]-in* hole 9 x1 & ! "u-side is cut away = "o-eigh? ( an in* 9 dep? & "o in* & a half 9 diamet]4 ,! object ( ^! depressions 9 block ,a & face-plate ,b is to give space = ! diaphragm 7,d7 to vibrate :5 ! voice falls on x ?r\gh ! m\?-piece 7,c74 ,f c>bon "o-eigh? ( an in* 9 ?ickness two r\nd buttons are cut measur+ ?ree-qu>t]s ( an in* across4 ,a small hole is bor$ 9 ! c5tre ( ea* button1 & "o ( !m is provid$ ) a v small brass screw & nut1 z %[n at ,f ,f4 ,"o side ( ! button-hole is c\nt]sunk1 s t ! head ( ! screw w fit d[n into x & be flu% ) ! face ( ! c>bon4 ,) a small ?ree-corn]$ or squ>e file cut ! surface ( ! buttons ) criss-cross l9es1 z %[n at ,f ,f4 ,:5 ! buttons are m\nt$ 9 ! receiv] ^! surfaces w face ea* o!r4 ,cut a small wa%] f felt or flannel1 & place x 9 ! bottom ( ! hole 9 block ,a4 ,l9e ! side ( ! hole ) a n>r[ /rip ( ! same goods2 !n place ! button 7,f ,f7 9 ! hole1 pass ! screw ?r\gh ! hole & ?r\gh ! block 7,a71 & make x fa/ ) ! nut1 z %[n at ,f4 ,place a ?91 flat wa%] "u ! nut1 & twi/ a f9e piece ( insulat$ copp] wire betwe5 wa%] & nut = t]m9al connections1 tak+ c>e t ! end ( ! wire "u ! nut is b>e & bright1 s t p]fect contact is assur$4 ,s9ce ! practice ( telephony involves su* delicate & s5sitive vibratory & electrical ph5om5a1 x is be/ to sold] all jo9ts & unions :]ev] practicable1 & s avoid ! possibility ( loose connections or corrosion ( unit$ wires4 ,f v ?9 f]rotype plate cut a piece two in*es squ>e1 & at ! middle ( x atta* ! o!r c>bon button by means ( a small rivet :i* y c make f a piece ( copp] wire4 ,or a v small brass ma*9e screw may be pass$ ?r\gh ! button & plate2 !n g5tly tapp$ at ! face ( ! plate to rivet x fa/1 z %[n at ,e4 ,lay ! block d[n flat & p>tly fill ! cavity ) c>bon granules until ! button is cov]$4 ,d n fill up to ! top ( ! hole4 ,ov] ?is lay ! disk 7,d71 s t ! c>bon button at ! "u side ( x w fit 9 ! top "p ( ! hole betwe5 ! sides ( felt or flannel4 ,make ! disk fa/ to ! block 7,a7 ) small p9s made by clipp+ ord9>y p9s 9 half & fil+ ! ends4 ,a slim bolt 7,g7 is pass$ ?r\gh ! block 7,a71 & a wire t]m9al is caught "u a nut & betwe5 a wa%] at ! back ( ! block1 z describ$ = ,f4 ,! japan or lacqu] mu/ be scrap$ away f ! disk 7,d7 :]e ! bolt-head t\*es x1 s t p]fect electrical contact w be ! result4 ,a small t9 funnel is cut & made fa/ to ! face-plate 7,b71 or if an electrical supply-h\se is at h& a m\?-piece ( h>d rubb] or composition may be _h = a few c5ts4 ,! block 7,b7 is !n screw$ fa/ to ,a1 =m+ ! transmitt] %[n at ,fig4 #i4 ,:5 ?is transmitt] /&s 9 a v]tical position ! granules1 or small p>ticles ( c>bon1 drop d[n betwe5 ! buttons ( c>bon1 pack+ closely at ! bottom ( ! cavity4 ,at ! middle !y are loosely plac$1 & at ! top !re are none4 ,z ! high or l[ vibrations ( ! voice fall on ! disk 7,d7 !y act accord+ly on ! c>bon granules1 :i* 9 turn conduct ! vibrations to ! re> c>bon button1 &1 by ! aid ( electricity reproduce ! same s\nd1 9 high or l[ tone1 ?r\gh ! receiv] at ! o!r end ( a l9e4 ,?is improv$ transmitt] makes x possible to talk 9 a mod]ate tone ( voice ov] di/ances up to "o ?\s& miles1 :ile ) ! old =m ( ! in/rum5t x 0 necess>y to talk v l\d 9 ord] to be he>d only a few miles away4 ,:]e a portable app>atus is desir$1 ?is block may be atta*$ to a box or an upright /aff4 ,?is transmitt] w n "w :5 on its back or s t ! funnel is on top1 because ! p>ticles ( c>bon w\ld settle on ! re> button & n t\* ! front "o4 ,x is ess5tial t ! c>bon gra9s %\ld t\* bo? buttons at ! same "t1 & at ! l[] "p ( ! cavity !y %\ld lie q solid4 ,x is n necess>y1 h[ev]1 to pack x 91 = ! vibratory action ( ! voice1 or o!r s\nds1 w cause ! p>ticles to adju/ !mselves & settle 9 a compact mass4 ,ano!r ,=m ( ,transmitt] ,9 ,fig4 #aa ano!r /yle ( transmitt] is %[n4 ,x is assembl$ on ! front ( a box4 ,?is front or cov] sw+s on h+es1 & c be op5$ s t ! me*anism 9 ! int]ior ( ! box may be gott5 at easily4 ,a sectional view ( ?is transmitt] is %[n 9 ,fig4 #ab4 ,a hole "o in* & a half 9 diamet] is cut 9 ! cov] 7,a74 ,a r\nd or squ>e block 7,b7 two in*es & a qu>t] across & half an in* ?ick is made fa/ to ! re> ( ! cov]1 & 9 ?is a hole is bor$ sev5-eigh?s ( an in* 9 diamet] & "o-qu>t] ( an in* deep4 ,! sides & bottom ( ?is hole are l9$ ) flannel or felt1 & a c>bon button ) r\gh5$ surface1 z %[n at ,f ,f1 is made fa/ 9 x by a small ma*9e screw & nut 7,f74 ,a diaphragm 7,d7 is cut f ?9 f]rotype plate1 & a c>bon button is made fa/ to ! middle ( x by a small ma*9e screw or a rivet made f s(t copp] or brass4 ,:5 ! block 7,b7 has be5 screw$ fa/ to ,a1 place "s granules ( c>bon 9 ! space 7,h72 !n lay ! diaphragm ov] ! op5+1 & make x fa/ ) small screws or p9s driv5 ar\nd ! edge4 ,f a small t9 funnel & a t9-c cap make a m\?-piece 7,c7 by cutt+ a hole 9 ! cap & slipp+ ! funnel ?r\gh x1 !n cutt+ ! end ( ! funnel t projects ?r\gh ! hole & b5d+ back ! e>s s t !y lap on ! inn] side ( ! cap4 ,^! small e>s may be sold]$ to ! cap s z to hold ! m\?-piece securely 9 place4 ,f felt or flannel cut a wa%] ! size ( ! c top & ab\t ?ree-eigh?s ( an in* 9 wid?4 ,lay ?is ov] ! diaphragm2 !n place ! m\?-piece on x & fa/5 x to ! door 7,a7 ) small screws4 ,! use ( ?is wa%] is to prev5t any false vibrations 9 ! m\?-piece affect+ ! s5sitive diaphragm4 ,make a small hole ?r\gh ,a & ,b & pass a bolt 7,e7 ?r\gh ?is hole1 tak+ c>e to lap a ?9 piece ( %eet-brass on ! diaphragm 7,d71 b5d+ x ov] s t x w lie "u ! head ( ! bolt 7,e74 ,! diaphragm mu/ be scrap$ :]e ! metal t\*es x1 s z to make p]fect electrical connection betwe5 ,d & ,e4 ,at ! re> end ( ,e arrange a wa%] & nut 7,g71 s t ! curr5t pass+ 9 at ,g travels ?r\gh ,e & ,d1 !n ?r\gh ! c>bon buttons & granules1 & out at ,f4 ,f p9e or :ite-wood "o-qu>t] or ?ree-eigh?s ( an in* ?ick make a box f\r in*es wide1 six in*es high1 & two in*es & a half deep4 ,to ! front ( ?is atta* a cov]1 :i* %\ld measure a qu>t] ( an in* l>g] all ar\nd ?an ! wid? & height ( ! box4 ,use brass h+es = ?is "w s t ! cov] may be op5$4 ,fa/5 a transmitt] to ! front ( ! cov]1 or make "o on ! cov]1 z %[n 9 ,fig4 #aa1 & atta* ! box to a back-bo>d or wall-plate five in*es wide & sev5 in*es high made ( p9e or :ite-wood half an in* 9 ?ickness 7see ,fig4 #ac74 ,illu/ration3 ,,fig4 #ac ,illu/ration3 ,,fig4 #ad ,illu/ration3 ,,fig4 #ae ,illu/ration3 ,,fig4 #af ,at ! left side ( ! box cut a slot ?r\gh ! wood1 s t a lev] & hook may project & "w up & d[n4 ,! end ( ?is lev] is provid$ ) a hook on :i* a receiv] may be hung1 z %[n 9 ,fig4 #ac1 & ! inside me*anism is arrang$ z %[n at ,fig4 #ad4 ,a is an angle-piece ( brass or copp]1 :i* acts z a bracket & :i* is screw$ fa/ to ! inside ( ! box4 ,b is ! lev] & hook1 :i* is cut f a /rip ( brass4 ,! atta*$ end is made wid]1 & an e> 7,c71 to :i* a wire is sold]$1 projects d[n beyond ! screw4 ,a view look+ d[n on ?is lev] & bracket is %[n at ,fig4 #ae4 ,a is ! bracket1 ,b ! lev]1 & ,e ! screw or bolt hold+ ! two p>ts toge!r1 ) a ?9 copp] wa%] betwe5 !m to prev5t friction4 ,:5 ! lev] & bracket are made fa/ to ! box1 a spr+ 7,d7 %\ld be arrang$1 s t :5 ! receiv] is remov$ f ! hook ! lev] w be drawn up to ! top ( ! slot4 ,a small contact-plate 7,f7 is made ( brass1 & fa/5$ at ! l[] end ( ! slot4 ,on ?is ! lev] %\ld re/ :5 ! receiv] is on ! hook4 ,a contact-wire is sold]$ to ?is plate1 :i* 9 turn is screw$ fa/ to ! inside ( ! box4 ,?is me*anism is "p ( a make-&-break swit* to cut out & cut 9 ! bells or telephone1 & w be m cle>ly und]/ood by ref]r+ to ! diagram 9 ,fig4 #ag4 ,at ! "r side ( ! box a small pu%-button is made fa/1 & ?is1 ) two b9d+-po/s at ! top & f\r at ! und]side ( ! box1 w complete ! ext]ior equipm5t ( "o end ( a l9e4 ,! con/ruction ( ! pu%-button is %[n 9 ,fig4 #af1 ,a be+ ! box & ,b ! button :i* passes ?r\gh a small hole made 9 ! side ( ! box4 ,c is a /rip ( spr+-brass screw$ fa/ to ! box4 ,x mu/ be /rong en\gh to press ! small bone or h>d rubb] button t[>ds ! outside ( ! box4 ,a wire is caught "u "o screw-head1 & ano!r "o is pass$ "u ! screw-head :i* holds ! o!r spr+ 7,d7 to ! box4 ,:5 ! button 7,b7 is pu%$ 91 x br+s spr+ ,c into contact ) ,d1 & ! circuit is clos$4 ,directly ! f+] is remov$ f ,b ! spr+ 7,c7 pu%es x out & breaks ! circuit4 ,?is button is us$ only 9 connection ) ! call-bells1 & has no?+ to d ) ! telephone4 ,! wires lead+ f ! int]ior ( ! box pass ?r\gh ! wall-plate & along 9 grooves to ! foot ( ! b9d+-po/s1 :i* are arrang$ bel[ ! box on ! back-bo>d1 z %[n 9 ,fig4 #ac4 ,a buzz] or bell is made fa/ to ! inside ( ! box1 unless x is too l>ge to fit conv5i5tly1 9 :i* case x may be atta*$ to ! wall above or bel[ ! box4 ,! ,wir+ ,sy/em ,fig4 #ag %[s ! wir+ sy/em = ?is outfit1 :i*1 :5 prop]ly set up & connect$1 %\ld op]ate on a circuit or l9e sev]al miles 9 l5g?1 provid$ t ! batt]ies are /rong en\gh4 ,?is sy/em may be in/all$ 9 ! box %[n 9 ,fig4 #ac1 ! flexible cord conta9+ two wires be+ atta*$ to ! b9d+-po/s at ! top ( ! box & to ! po/s at ! end ( ! receiv]4 ,?is sy/em diff]s f ! "o %[n 9 ,fig4 #f only 9 ! addition ( receiv]s ,t & ,t #b1 & 9 ! sub/itution ( ! automatic lev]-swit*es 7,l ,s & ,l ,s #b7 = ! pla9 swit*es 7,s & ,s #b7 9 ,fig4 #f4 ,:5 ! l9e is 8quiet0 ! receiv] 7,r7 %\ld be hang+ on ! lev]-swit* 7,l ,s71 :i* re/s on ! contact-plate 7,a74 ,at ! opposite side ( ! l9e ! receiv] 7,r #b7 hangs on ! lev]-swit* 7,l ,s #b71 :i* 9 turn re/s on ! contact-plate 7,a ,a74 ,?is puts ! bell circuit 9 s]vice4 ,illu/ration3 ,,fig4 #ag ,,plan ,,( ,,telephone ,,circuit1 ,,compris+ ,,receiv]s1 ,,transmitt]1 ,,electric ,,buzz]s ,,or ,,bells1 ,,lev]-,,swit*es1 ,,pu%-,,buttons ,,& ,,batt]ies ,,= ,,/ations ,,n ,,ov] ,,five ,,miles ,,ap>t4 ,if ! boy at ! left wi%es to call up ! boy at ! "r he removes ! receiv] 7,r7 f ! hook 7,l ,s7 & presses on ! button 7,p ,b74 ,?is closes ! circuit ?r\gh ! batt]y 7,c ,c ,c71 & op]ates ! electric buzz] or bell 7,e ,b #b7 at ! o!r end ( ! sy/em1 ?r\gh l9e ,no4 #a & l9e ,no4 #b4 ,! op]ation may be cle>ly und]/ood by foll[+ ! l9es 9 ! draw+ ) a po9t]4 ,! boy at ! left may keep on call+ ! boy at ! "r s long z ! receiv] 7,r #b7 hangs on ! lev] 7,l ,s #b7 & holds x d[n aga9/ ! plate 7,a ,a74 ,b directly ! receiv] 7,r #b7 is remov$1 ! lev] 7,l ,s #b7 flies up--be+ drawn upw>d by ! spr+ 7,d7 %[n 9 ,fig4 #ad--;& closes ! telephone circuit ?r\gh ! spr+-contact 7,b ,b71 at ! same "t cutt+ out ! bell circuit4 ,! boy at ! left hav+ already remov$ 8 receiv]1 ! telephone circuit is !n complete ?r\gh l9es ,nos4 #a & #b & batt]ies ,c ,c ,c & ,c #b ,c #b ,c #b1 ! boys at bo? ends speak+ into ! transmitt]s & he>+ ?r\gh ! receiv]s4 ,! contacts ,b & ,b ,b are made f spr+-brass or copp]1 & are atta*$ inside ! boxes at ! back1 s t :5 ! lev]s are up contact is made1 b :5 d[n ! circuit is brok5 or op5$4 ,9 ,fig4 #ah an int]ior view ( a box is %[n1 ! door be+ ?r[n op5 & ! receiv] left hang+ on ! hook4 ,illu/ration3 ,,fig4 #ah ,,fig4 #ai ,,fig4 #bj ,,telephone ,,in/allation4 ,,int]ior ,,view ,,( ,,box ,! arrangem5t ( ! sev]al p>ts w be f\nd conv5i5t & easy ( access4 ,e ,b is ! electric buzz]1 ,l ,s ! lev]-swit*1 ,p ,b ! pu%-button1 ,t ! transmitt]1 & ,r ! receiv]4 ,nos4 #a1 #b1 #c1 #d1 #e1 #f1 #g1 #h are b9d+-po/s or t]m9als1 & ,b is ! spr+-contact aga9/ :i* ! lev]-swit* 7,l ,s7 /rikes :5 drawn up by ! spr+ 7,d74 ,! wires t pass f #f to #g & f #d to #h %\ld be sold]$ fa/ to "o side ( ! h+e1 & ^? runn+ f ! t]m9als or nuts at ! back ( ! transmitt] 7,t7 to #g & #h %\ld be simil>ly secur$4 ,small brass h+es are n liable to become corrod$ at ! jo9ts1 b to insure aga9/ any su* possibility ! ends ( sev]al f9e wires may be sold]$ to ea* leaf ( ! h+e1 s t :5 ! door is clos$ ! wires w be compress$ betwe5 ! h+e-plates4 ,= long-di/ance communication x w be necess>y to in/all an induction-coil1 s t ! direct curr5t furni%$ by ! batt]ies1 9 s]ies ) ! transmitt]1 c by induction be trans=m$ into alt]nat+ curr5t ov] ! l9es connect+ ! two sets ( app>atus4 ,?is sy/em is some:at m complicat$ & requires m c>e 9 mak+ ! connections1 b once 9 op]ation x w be f\nd f> sup]ior to ei!r ( ! sy/ems hi!rto describ$4 ,a ,telephone ,induction-coil ,x w be necess>y to make two induction-coils1 z describ$ 9 *apt] iv41 page #fb1 ,fig4 #h4 ,a telephone coil = mod]ately long-di/ance circuits is made on a wood5 spool turn$ f a piece ( wood ?ree in*es & a half long & "o in* squ>e1 z %[n at ,fig4 #ai4 ,! core-%ea? is turn$ d[n s t x is ab\t "o-sixte5? ( an in* ?ick4 ,?is spool is giv5 a coat or two ( %ellac1 & two holes are made at ea* end1 z %[n 9 ! draw+4 ,! fir/ w9d+ or prim>y coil is made up ( two lay]s ( ,no4 #bj d\ble-insulat$ copp] wire1 "o end project+ f a hole at "o end ( ! spool1 ! o!r f a hole at ! o!r end4 ,?is coil is giv5 two or ?ree ?9 coats ( %ellac to b9d ! /r&s ( wire & ?or\ghly insulate !m1 & ov] ! lay] a piece ( pap] is to be wrapp$ & %ellack$4 ,! second>y coil is made up ( twelve lay]s ( ,no4 #cd silk-insulat$ copp] wire1 & betwe5 ea* lay] a %eet ( pap] %\ld be w\nd s t x w make two complete wraps4 ,ea* pap] sep>ator %\ld be giv5 a coat ( %ellac or hot p>aff9e2 !n ! turns ( wire %\ld be cont9u$ j z ?read is w\nd ^u a spool1 smoo?ly1 closely1 & ev5ly1 until ! la/ wrap is on4 ,?ree or f\r wraps ( pap] %\ld be fa/5$ on ! coil to protect x1 & x may !n be screw$ fa/ inside a box4 ,! core-hole )9 ! coil %\ld be pack$ ) l5g?s ( ,no4 #bd s(t ,sw$es iron wire ?ree in*es & a half long4 ,9 ,fig4 #ai ! wires are %[n project+ f ! end ( a spool1 & ,fig4 #bj depicts a complet$ telephone induction-coil4 ,! in/allation ( ! induction-coils is %[n 9 ,fig4 #ba4 ,illu/ration3 ,,fig4 #ba ,,plan ,,( ,,telephone ,,circuit1 ,,compris+ ,,receiv]s1 ,,transmitt]s1 ,,electric ,,buzz]s ,,or ,,bells1 ,,lev]-,,swit*es1 ,,induction-,,coils1 ,,pu%-,,buttons1 ,,& ,,batt]ies ,,= ,,/ations ,,up ,,to ,,five ,,hundr$ ,,miles ,,ap>t4 ,! wir+ is comp>atively simple1 & may be easily foll[$ if ! description & plan are con/antly consult$ :5 sett+ up ! l9e4 ,r & ,r #b are ! receiv]s1 ,t & ,t #b ! transmitt]s1 ,c #a & ,c #b ! batt]ies1 ,e ,b & ,e ,b #b ! buzz]s or bells1 ,p ,b & ,p ,b #b ! pu%-buttons1 & ,l ,s & ,l ,s #b ! lev]-swit*es4 ,= conv5i5ce ( illu/ration ! induction-coils are sep>at$4 ,! prim>y coil 7,p ,c7 is indicat$ by ! heavy spr+ l9e & ! second>y coil 7,s ,c7 by ! f9e spr+ l9e4 ,:5 ! l9e is 8dead0 bo? receiv]s are hang+ f ! hooks ( ! lev]-swit*es4 ,if ! boy at ! left wi%es to call ! boy at ! "r he lifts ! receiv] 7,r7 f ! hook 7,l ,s7 & presses ! button 7,p ,b74 ,?is ?r[s ! batt]y 7,c #a ,c #a ,c #a7 9 circuit ) l9es ,nos4 #a & #b1 & op]ates ! buzz] 7,e ,b #b74 ,:5 ! boy at ! "r lifts 8 receiv] 7,r #b7 f ! hook 7,l ,s #b71 ! bell circuit is cut out & ! 'phone circuit is cut 94 ,:5 ! lev]-swit*es are drawn up aga9/ ! contact-spr+s 7,a1 ,b1 & ,c & ,a ,a1 ,b ,b1 & ,c ,c71 bo? batt]ies are ?r[n into circuit ) ! transmitt]s at _! respective ends ?r\gh ! prim>y coils 7,p ,c & ,p ,c #b74 ,by inductance ?r\gh ! second>y coils 7,s ,c & ,s ,c #b71 l9es ,nos4 #a & #b are electrifi$1 & :5 ! voice /rikes ! disks 9 ! transmitt]s ! same tone & vibration is he>d ?r\gh ! receiv]s at ! o!r end ( ! l9e4 ,:ile conv]sation is go+ on ! batt]ies at ei!r end are be+ drawn ^u or deplet$2 b z soon z ! receiv]s are hung on ! hooks & ! lev]-swit*es are drawn away f ! contact-spr+s1 ! fl[ ( curr5t is /opp$4 ,! buzz]s or bells consume b a small am\nt ( curr5t :5 op]at$1 & 9 dry cells ! active p>ts recup]ate quickly & depol>ize4 ,! greate/ dra9 on a batt]y1 !re=e1 is :5 ! l9e is clos$ = conv]sation4 ,an ,in/allation ,plan ,a simple mann] 9 :i* to in/all ?is app>atus 9 boxes is %[n 9 ,fig4 #bb4 ,! box is depict$ ) ! front op5$ & ) ! receiv] hang+ on ! hook4 ,:5 ! lev]-swit* 7,l ,s7 is d[n x re/s on ! contact-spr+ 7,a71 ?us ?r[+ 9 ! bell circuit4 ,:5 ! boy at ! o!r end ( ! l9e pu%es ! button on 8 box x op]ates ! buzz] 7,e ,b74 ,?is c be und]/ood by foll[+ ) a po9t] ! wires f ! buzz] to ! outlet-po/s 7,nos4 #a & #c7 at ! bottom ( ! wall-plate4 ,illu/ration3 ,fig4 #bb ,:5 ! receiv] 7,r7 is lift$ f ! hook 7,l ,s71 x cuts out ! bell circuit & cuts 9 ! telephone circuit1 ?r\gh ! spr+-contacts 7,b & ,c74 ,?is circuit may easily be foll[$ ?r\gh ! wires connect+ transmitt]1 receiv]1 induction-coil1 & batt]ies4 ,! heavy l9es lead+ out f ! induction-coil are ! prim>y coil wires1 & ! f9e hair l9es are ^? =m+ ! second>y coil4 ,! m$ium l9es are ^? t connect ! b9d+-po/s1 batt]ies1 & l9es4 ,:5 ! bell circuit is connect$ ! impulse com+ f ! o!r end ( ! l9e ent]s ?r\gh wire ,no4 #aj to po/ ,no4 #c1 !nce to /rip ,e & plate ,g1 & s on to ,e ,b1 :i* x op]ates4 ,! curr5t !n passes f ,e ,b to contact ,a1 ?r\gh ,l ,s to po/ ,no4 #a1 & out on wire ,no4 #aa4 ,to op]ate ! buzz] at o!r end ( ! l9e ! button 7,p ,b7 is pu%$ 94 ,?is moves ! spr+ 7,e7 away f ! plate 7,g71 & br+s x into contact ) ,f4 ,?is connects ! circuit ?r\gh ! batt]y wire 7,no4 #h7 to po/ ,no4 #a to l9e ,no4 #aa )\t go+ into ! box1 & f wire ,no4 #i to po/ ,no4 #b2 !nce to h+e ,no4 #g to plate ,f1 ?r\gh ,e1 d[n to po/ ,no4 #c1 & out ?r\gh wire ,no4 #aj4 ,9 ?is mann] ! curr5t is tak5 f ! batt]ies at ! foot ( wires ,nos4 #h & #i1 & us$ to r+ ! buzz] at ! o!r end ( ! l9e4 ,:5 ! hook 7,l ,s7 is up ! circuit is clos$ ?r\gh ,t1 ,i ,c1 & batt]y4 ,! curr5t runs f ! batt]y ?r\gh wire ,no4 #h to po/ ,no4 #a1 to ,l ,s1 ?r\gh ,c & prim>y coil out to h+e ,no4 #f1 ?r\gh transmitt] to h+e ,no4 #g1 to po/ ,no4 #b1 & back to batt]y ?r\gh wire ,no4 #i4 ,by inductance ! s\nd is c>ri$ ov] ! l9e1 9 at wire ,no4 #aj1 to po/ ,no4 #c1 ?r\gh second>y coil to po/ ,no4 #d1 ?r\gh receiv] ,r to po/ ,no4 #e1 ?r\gh ,b & ,l ,s to po/ ,no4 #a1 & out ?r\gh wire ,no4 #aa4 ,at ! o!r end ( ! l9e x goes ?r\gh ! same p>ts ( ! app>atus4 ,a ,portable ,app>atus ,= conv5i5ce x is (t5 desirable to h a portable transmitt]1 & s avoid ! inconv5i5ce ( hav+ to /& :ile speak+4 ,a neat portable app>atus t w /& on a l$ge or table1 & :i* may be mov$ ab\t )9 ! radius ( ! connect+ l9es1 is %[n 9 ,fig4 #bc4 ,! wood5 base is f\r in*es squ>e & ! upright "o in* & a half squ>e4 ,! /& is twelve in*es high ov] all1 & on ! bottom a plate ( iron or lead mu/ be screw$ fa/ to make x bottom-heavy1 s t x w n topple ov]4 ,! lev]-swit* may be arrang$ at ! back ( ! upright & ! pu%-button at ! front ne> ! base1 z %[n at ,a4 ,! wall-box conta9s ! buzz] & induction-coil1 & )9 x ! wir+ is arrang$ f ! portable /& to ! batt]ies & l9e z %[n at ,c4 ,?is illu/ration is too small1 h[ev]1 to %[ ! complete wir+1 & ! "y electrician is !re=e ref]r$ to ,fig4 #bb4 ,! batt]y 7,b7 is compos$ ( z _m dry or wet cells z may be requir$ to op]ate ! l9e4 ,^! mu/ be connect$ 9 s]ies at bo? ends4 ,at ,d a re> view ( ! upright & transmitt] is %[n to illu/rate ! mann] 9 :i* ! wir+ c be done4 ,if a holl[ upright is made ( f\r ?9 pieces ( wood a mu* neat] appe>ance may be secur$ by enclos+ ! wires4 ,illu/ration3 ,,fig4 #bc ,a ,,portable ,,app>atus ,9 all ( ^! telephone sy/ems "o wire mu/ lead to ! gr\nd1 or be connect$ ) a wat]-pipe1 tak+ c>e1 h[ev]1 to sold] ! wire to a galvaniz$ pipe s t p]fect contact w be ! result4 ,if ! wire is c>ri$ directly to ! gr\nd x mu/ be atta*$ to a plate1 :i* 9 turn is buri$ deep en\gh to rea* moi/ e>?1 z describ$ 9 ! *apt] on ,l9e & ,wireless ,telegraphs1 page #bae4 ,c>e & accuracy w lead to success 9 telephony1 b "o slip or error w ?r[ ! be/ sy/em out ( ord] & r5d] x useless4 ,?is1 inde$1 applies to all electrical app>atus2 !re c be no half-way2 x w ei!r "w or x won't4 ,*apt] ,,ix ,,l9e ,,& ,,wireless ,,telegraphs ,a ,gr\nd ,telegraph ,ne>ly e boy is int]e/$ 9 telegraphy1 & x is a fasc9at+ field = /udy & exp]im5tal "w1 to say no?+ ( ! amusem5t to be gott5 out ( x4 ,! in/rum5ts are n difficult to make1 & two boys c easily h a l9e betwe5 _! h\ses4 ,! key is a modifi$ =m ( ! pu%-button1 & is simply a contact mak] & break] = op5+ & clos+ an electrical circuit4 ,a practical telegraph-key is %[n 9 ,fig4 #a1 & 9 ,fig4 #b is giv5 ! side elevation4 ,! base-bo>d is f\r in*es wide1 six in*es long1 & half an in* 9 ?ickness4 ,at ! front end a small metal connector-plate is screw$ fa/1 & ?r\gh a hole 9 ! middle ( x a brass-head$ uphol/]]'s tack is driv5 = ! und]side ( ! key to /rike aga9/4 ,two ,l pieces ( metal are b5t & atta*$ to ! middle ( ! bo>d to support ! key-b>1 & at ! re> ( ! bo>d ano!r uphol/]]'s tack is driv5 9 ! wood = ! end ( ! b> to /rike on & make a click4 ,! b> is ( brass or iron1 measur+ ?ree-eigh?s by half an in*1 & is provid$ ) a hole bor$ at an equal di/ance f ea* end = a small bolt to pass ?r\gh1 9 ord] to pivot x betwe5 ! ,l plates4 ,a hole made at ! =w>d end w admit a brass screw t 9 turn w hold a spool-end to act z a f+]-piece4 ,! screw %\ld be cut (f & rivet$ at ! und]side4 ,a %ort1 /rong spr+ is to be atta*$ to ! back ( ! base-block & to ! end ( ! key-b> by means ( a hook1 :i* may be made f a /eel-wire nail flatt5$4 ,x is b\nd to ! top ( ! b> ) wire1 z %[n 9 ,figs4 #b & #c4 ,illu/ration3 ,,fig4 #a ,illu/ration3 ,,fig4 #d ,! incom+ & outgo+ wires are made fa/ to "o end ( ! connector-plate & to "o ( ! ,l pieces t support ! key4 ,:5 ! key is at re/ ! circuit is op51 b :5 press$ d[n aga9/ ! brass tack x is clos$1 & :e!r press$ d[n or releas$ x clicks at bo? movem5ts4 ,a simple swit* may be connect$ ) ! ,l-plate & ! connection-po/ at ! opposite side ( ! key-base1 s t1 if necess>y1 ! circuit may be clos$4 ,or an arm may be caught "u ! screw at ! ,l-plate1 & br\ght =w>d s t x c be ?r[n 9 aga9/ a screw-head on ! connector-plate1 z %[n 9 ,fig4 #c4 ,! screw-head may be flatt5$ ) a file1 & ! und]side ( ! swit* bevell$ at ! edges1 s t x w m\nt easily on ! screw4 ,9 ,fig4 #d 7page #aia7 a simple telegraph-s\nd] is %[n4 ,a base-bo>d1 f\r in*es wide1 six in*es long1 & sev5-eigh?s ( an in* 9 ?ickness1 is made ( h>d-wood1 & two holes are bor$1 ) ! c5tres two in*es f "o end1 s t ! l[] nuts ( ! horse%oe magnet w fit 9 !m1 z %[n 9 ,fig4 #e4 ,?is all[s ! yoke to re/ flat on ! top ( ! base1 & ) a /\t screw pass$ d[n ?r\gh a hole 9 ! middle ( ! yoke & into ! wood ! magnets are held 9 an upright position4 ,f ! base-block to ! top ( ! bolt ! magnets are two in*es & a qu>t] high4 ,! b> ( brass or iron to :i* ! armature 7,a 9 ,fig4 #e7 is atta*$ is f\r in*es & a half 9 l5g? & ?ree-eigh?s by half an in* ?ick4 ,at ! middle ( ! b> & ?r\gh ! side a hole is bor$1 ?r\gh :i* a small bolt may be pass$ to hold x betwe5 ! upright blocks ( wood4 ,at ! front end two small holes are to be bor$1 s t its armature may be rivet$ to x ) brass escut*eon-p9s or slim r\nd-head$ screws4 ,! heads are at ! top & ! rivet+ is und]nea?4 ,a small block ( wood is cut1 z %[n 9 ,fig4 #f1 aga9/ :i* ! two upright pieces ( wood are made fa/4 ,?is block is two in*es & a half long1 "o in* & a qu>t] high1 & sev5-eigh?s ( an in* wide4 ,! laps cut f ea* side are an in* wide & a qu>t] ( an in* deep1 to receive ! uprights ( ! same dim5sions4 ,at ! top ( ?is block a brass-head$ nail is driv5 = ! und]side ( ! b> to /rike on4 ,a hook & spr+ are to be atta*$ to ! re> ( ! s\nd]-b>1 z describ$ = ! key1 & at ! front ( ! base two b9d+-po/s are arrang$1 to :i* ! loose ends ( ! coil-wires are atta*$4 ,j beh9d ! yoke1 & directly "u ! armature-b>1 a long screw is driv5 into ! base-block1 z %[n at ,b 9 ,fig4 #e4 ,x mu/ n t\* ! yoke1 & ! head %\ld be less ?an "o-eigh? ( an in* bel[ ! b> :5 at re/4 ,on ?is ! armature-b> /rikes & clicks :5 drawn to ! magnets4 ,! armature mu/ n t\* ! magnets2 o!rwise ! residual magnetism w\ld hold x d[n4 ,! screw mu/ be nicely adju/$1 s t a l\d1 cle> click w result4 ,illu/ration3 ,,fig4 #b ,,fig4 #c ,,fig4 #e ,,fig4 #f ,,fig4 #h ,,telegraph ,,key ,,& ,,s\nd] ,:5 ! s\nd] is at re/ ! re> end lies on ! brass tack 9 ! block1 & ! armature is ab\t a qu>t] ( an in* above ! top ( ! magnets4 ,! armature is ( s(t iron1 two in*es & a half long1 sev5-eigh?s ( an in* wide1 & an eigh? ( an in* ?ick4 ,^! small scraps ( metal may be procur$ at a blacksmi?'s %op1 &1 = a few c5ts1 he w bore ! holes 9 ! requir$ places2 or if y h a brea/ or h& drill ! metal may be held 9 a vise & prop]ly p]=at$4 ,by connect+ "o wire f ! key directly ) "o ( ! b9d+-po/s ( ! s\nd]1 & ! o!r ) ! poles ( a batt]y1 & s on to ! s\nd]1 ! app>atus is ready = use4 ,by press+ on ! key ! circuit is clos$1 & ! magnetism ( ! s\nd]-cores draws ! armature d[n ) a click4 ,on releas+ ! key ! b> flies back to re/1 hav+ be5 pull$ d[n by ! spr+1 & x clicks on ! brass tack-head4 ,^! two in/rum5ts may be plac$ any di/ance ap>t1 miles if necess>y1 s long z suffici5t curr5t is employ$ to "w ! s\nd]4 ,two sets ( in/rum5ts mu/ be made if boys 9 sep>ate h\ses are to h a l9e4 ,ea* "o mu/ h a key1 s\nd]1 & cell1 or sev]al cells connect$ 9 s]ies to =m a batt]y1 accord+ to ! curr5t requir$4 ,9 ! plan ( ! telegraph-l9e connections 7,fig4 #g1 page #aif7 a cle> idea is giv5 = ! wir+2 & if ! l9e & return wires are to be v long1 x w\ld be be/ to h !m ( ,no4 #ad galvaniz$ telegraph-wire1 copp] be+ too exp5sive1 al?\gh mu* bett]4 ,^! wires mu/ n t\* ea* o!r1 & :5 atta*$ to a h\se1 b>n1 or trees1 porcela9 or glass insulators %\ld be us$4 ,if no?+ bett] c be _h1 ! necks ( "s /\t glass bottles may be held ) wood5 p9s or l>ge nails1 & ! wire twi/$ to !m1 z %[n 9 ,fig4 #h4 ,:5 ! l9e is n 9 use ! swit*es on bo? keys %\ld be clos$2 o!rwise x w\ld be impossible = ! boy hav+ ! clos$ swit* to call up ! boy ) ! op5 "o4 ,take great c>e 9 wir+ y\r app>atus to /udy ! plan1 = a misconnect$ wire w ?r[ ! :ole sy/em out ( ord]4 ,illu/ration3 ,,fig4 #g ,to op]ate ! l9e see t all swit*es are clos$ & t ! connections are 9 good condition4 ,:5 ! boy 9 h\se ,no4 #b wants to call up 8 fri5d 9 h\se ,no4 #a he ?r[s op5 ! swit*on key1 z %[n 9 ! plan1 & by press+ d[n on ! f+]-key 8 s\nd] & t 9 h\se ,no4 #a click simultane\sly4 ,z soon z he raises or releases ! key ! armatures rise1 mak+ ! up-click4 ,if he presses 8 key & releases x quickly ! two clicks on ! s\nd] 9 h\se ,no4 #a are close toge!r2 ?is makes :at is call$ a dot4 ,if ! key is held d[n long] x makes a long "t betwe5 clicks1 & ?is is call$ a da%4 ,! dot & da% are ! two elem5ts ( ! telegraphic code4 ,y w und]/& t ! boy 9 h\se ,no4 #b he>s j :at ! "o 9 ,no4 #a is he>+1 s9ce ! electric curr5t pass+ ?r\gh bo? coils causes ! magnets to act 9 unison4 ,s soon z ! op]ator 9 h\se ,no4 #b has f9i%$ he closes 8 swit*1 & ! o!r 9 h\se ,no4 #a op5s 8 swit* on ! key & beg9s 8 reply4 ,?is is ! simple pr9ciple ( ! telegraph1 & all ! improv$ app>atus is bas$ on x1 no matt] h[ complicat$4 ,! complete ,morse alphabet is app5d$3 ,illu/ration3 ,! ,morse ,telegraph ,code ,any p]sev]+ boy c soon le>n ! dot-&-da% lett]s ( ! ,morse code1 & v quickly become a fairly good op]ator4 ,telegraphic messages are s5t & receiv$ 9 ?is way1 & are read by ! s\nd ( ! clicks4 ,v>i\s k9ds ( record+ in/rum5ts are also employ$1 s t :5 an op]ator is away f 8 table ! automatic record] takes d[n ! message on a pap] tape4 ,9 ! /ock-tick]1 employ$ 9 brok]age (fices1 ! record+ is done by lett]s & num]als1 & ! pap] tape drops into a basket beside ! ma*9e1 s t any "o pick+ up ! /rip ( pap] c see ! quotations f ! op5+ ( bus9ess up to ! "t ( read+ !m4 ,^! quotations are s5t out directly f ! floor ( ! ex*anges1 & by ! action ( "o man's h& ?\s&s ( ma*9es are set 9 op]ation all ov] ! city4 ,p]haps ! mo/ unique & wond]ful telegraphic signal-app>atus is t locat$ on ! floor ( ! ,new ,york ,produce ,ex*ange & ! ,*icago ,ex*ange4 ,! dials1 side by side1 are op]at$ by direct wire f ,*icago4 ,:5 ! ,new ,york op]ator fla%es a quotation x appe>s simultane\sly on ! ,new ,york dial & simultane\sly on ! ,*icago dial1 & vice v]sa4 ,electrical in/rum5ts are n ! only means by :i* ! ,morse alphabet may be transmitt$1 = 9 "s in/ances in/rum5ts w\ld be 9 ! way1 :ile 9 o!rs ! wires might be d[n & communication cut (f4 ,?is is int]e/+ly illu/rat$ by an ev5t 9 ,?omas ,a4 ,edison's life4 ,:5 he 0 a boy & an appr5tice telegraph op]ator on ! ,gr& ,trunk ,l9e1 an ice-jam _h brok5 ! cable betwe5 ,port ,huron1 9 ,mi*igan1 & ,s>nia1 9 ,canada1 s t communication by electricity 0 cut (f4 ,! riv] at t po9t is a mile & a half wide1 ! ice made ! passage impossible1 & !re 0 no way ( repair+ ! cable4 ,edison impulsively jump$ on a locomotive /&+ ne> ! riv]-bank & seiz$ ! :i/le-cord4 ,he _h an idea t bla/s ( ! :i/le might be brok5 into long & %ort s\nds correspond+ to ! dots & da%es ( ! ,morse code4 ,9 a mom5t ! :i/le s\nd$ ov] ! riv]3 8,toot1 toot1 toot1 toot1--toot1 tooooot1--tooooot--tooooot--toot1 toot--toot1 toot40 8,halloo1 ,s>nia6 ,d y get me8 ,d y he> :at ,i say80 ,no answ]4 8,d y he> :at ,i say1 ,s>nia80 ,a ?ird1 f\r?1 & fif? "t ! message w5t across1 to receive no response4 ,!n sudd5ly ! op]ator at ,s>nia he>d famili> s\nds1 &1 op5+ ! /ation door1 he cle>ly caught ! toot1 toot ( ! f>-away :i/le4 ,he f\nd a locomotive1 &1 m\nt+ to ! cab1 respond$ to ,edison1 & soon messages 7 toot$ back & =? z freely z ?\gh ! p>t$ cable 7 aga9 9 op]ation4 ,"s ye>s ago ! police ( ,new ,york 7 my/ifi$ ov] a murd] case4 ,! man !y suspect$ _h n fl$1 b 0 /ill 9 8 usual place1 & att5d+ to 8 bus9ess q z ?\gh no?+ _h happ5$ to connect him ) ! trag$y4 ,detectives 9 pla9 clo!s _h be5 foll[+ him & wat*+ closely 8 e move 9 & out ( re/aurants & %ops & at social affairs2 b n ! slighte/ pro( c\ld be secur$ aga9/ him4 ,"o noon-"t !y foll[$ him into a caf1 :]e he _h gone ) a fri5d4 ,! detectives took seats ne> him1 b ea* ( !m sat at diff]5t tables 9 ! room full ( p4 ,:5 9 ! caf ! suspect sat next ! wall1 a habit ! detectives _h notic$4 ,consequ5tly1 only ^? p]sons :o sat at "o side ( him or directly 9 front c\ld see 8 face4 ,dur+ ! "t !y 7 9 ! re/aurant ! detectives communicat$ ) ea* o!r by tapp+ on ! table tops ) a lead-p5cil2 & some?+ ! man said1 :i* ! ne>e/ detective he>d1 l$ to ! climax4 ,"o detective rose1 paid 8 *eck1 & loit]$ ne> ! door2 ano!r got up a little lat] & saunt]$ out1 b return$ ) a c>dbo>d sign4 ,go+ ov] to ! table :]e ! suspect$ crim9al & 8 fri5d sat1 he delib]ately tack$ x on ! wall above !m1 !n w5t out aga91 leav+ ! ?ird detective to wat* ! face ( ! man z he read3 #ajjj ,,rew>d = in=mation lead+ to ! arre/ ( ! murd]] ( ------------ on ,m>* --------1 #ahgf ,! man ca/ a glance ab\t ! re/aurant1 !n said to 8 companion3 8,did ,i %[ any signs ( agitation80 ,! ?ird detective rose1 /epp$ ov] to ! man1 tapp$ him on ! %\ld]1 & said1 8,i want y40 ,!re w\ld h be5 a sc5e ( viol5ce _h n ! o!r two detectives clos$ 9 on ! man1 & )9 six mon?s he paid ! p5alty ( 8 crime4 ,if x _h n be5 = ! dot-&-da% alphabet1 tapp$ out ) lead-p5cils1 ! detectives c\ld n h communicat$2 b l ,edison1 !y us$ ! means at h& to op5 up & c>ry on a sil5t conv]sation4 ,wireless ,telegraphy ,ev]ybody n[adays und]/&s t wireless telegraphy means ! transmission ( electrical vibrations ?r\gh ! e!r & e>? )\t ! aid ( wires or any visible means ( conductivity4 ,! feat ( s5d+ an electrical communication ov] ?\s&s ( miles ( wire1 or ?r\gh subm>9e cables1 is wond]ful en\gh1 = all t cu/om has made x an e-day miracle4 ,to accompli% ?is same end by s5d+ our messages ?r\gh ! app>5tly empty air is inde$ awe-inspir+ & almo/ beyond belief4 ,& yet we "k t wireless telegraphy is to-day a real sci5tific fact4 ,at fir/ sight x w\ld seem t ! in/rum5ts mu/ be complicat$ & necess>ily beyond ! ability ( ! av]age boy to make1 & f> too exp5sive z well4 ,z a matt] ( fact1 ! "y electrician may con/ruct 8 wireless app>atus at a v mod]ate co/1 x be+ und]/ood t ! s5d+ & receiv+ poles may be m\nt$ on a h\setop or b>n4 ,b fir/ let u consid] ! !ory ^u :i* we are to "w4 ,!re is no d\bt b t electricity is ! highe/ kn[n =m ( vibration--s high1 inde$1 t z yet man has be5 unable to inv5t any in/rum5t to record ! numb] ( pulsations p] second4 ,?is vibration w occur 91 & c be s5t ?r\gh1 ! ord9>y =m ( conductor1 su* z metals1 wat]1 fluids & liquids1 wet e>?1 air & ice4 ,also ?r\gh :at we call ! e!r4 ,n[ ! e!r ( ! atmosph]e1 e/imat$ to be fifte5 trillion times light] ?an air1 is ! m$ium ?r\gh :i* ! electrical vibrations pass 9 travell+ 9 _! radial direction f a c5tral po9t1 correspond+ to ! ripples or wavelets =m$ :5 a pond or surface ( /ill wat] is di/urb$4 ,e!r is s f9e a sub/ance t ! organs ( s5se are n delicate en\gh to detect x1 & x is ( su* a volatile & uneasy nature t x is cont9ually 9 motion4 ,x vibrates "u c]ta9 conditions1 & :5 di/urb$ 7z by a dynamo7 x und\bt$ly =ms ! active pr9ciple ( electricity & magnetism4 ,james ,cl>k ,maxwell believ$ t magnetism1 electricity1 & light are all transmitt$ by vibrations 9 "o common e!r1 & he f9ally demon/rat$ 8 !ory by prov+ t pulsations ( light1 electricity1 & magnetism diff]$ only 9 _! wave l5g?s4 ,9 #ahhg ,pr(essor ,h]tz succe$$ 9 e/abli%+ pro( positive t ,maxwell's !ories 7 correct1 &1 aft] elaborate exp]im5ts1 he prov$ t all ^! =ces us$ e!r z a common m$ium4 ,!re=e1 if x 7 n = ! e!r1 wireless telegraphy1 ) all its wond]s1 w\ld n be possible4 ,we und]/&1 !n1 t ! waves ( e!r are set 9 motion f a c5tral di/urb+ po9t1 & ?is c be accompli%$ only by means ( electrical impulse4 ,suppose t we /rike a bell held high 9 ! air4 ,! s\nd is ! result ( ! vibrations ( its mass s5d+ its pulsat+ en]gy ?r\gh ! air4 ,! l5g? ( ! s\nd-waves is measur$ 9 ! direction 9 :i* ! waves are travell+1 & if ! air is quiet & n di/urb$ by w9d ! s\nd w travel equally 9 all directions4 ,! s\nd ( a bell w n travel s well aga9/ a w9d z x w ) x1 j z ! ripples on a pond w\ld be *eck$ by an adv]se set ( wavelets4 ,n[ ! e!r c be made to vibrate 9 a simil> mann] to ! air by a *>ge ( electricity oscillat+ or surg+ to & fro on a wire sev]al hundr$ ?\s& times 9 a second4 ,^! oscillations /rike out & affect ! surr\nd+ e!r1 s t1 accord+ to ! int5sity ( ! disruptive *>ge at ! />t+-po9t1 ! e!r waves may be made to rea* ne> or di/ant po9ts4 ,?is is1 p]haps1 m cle>ly %[n by ! action ( a p5dulum4 ,9 ,fig4 #i ! rod & ball are at re/1 b if drawn to "o side & releas$ x sw+s ov] to ! o!r side ne>ly z f> away f its c5tral position ( re/ z f ! />t+-po9t4 ,if all[$ to sw+ to & fro x w oscillate until at la/ x w come to re/ 9 a v]tical position4 ,?is same oscillation 7oscillation be+ a =m ( vibration7 takes place 9 ! wat] :5 a /one has be5 flung into x1 & 9 ! e!r :5 affect$ by ! electrical dis*>ge4 ,9 ,fig4 #aj are %[n ! pr9cipal v>ieties ( vibration--! oscillat+1 pulsat+1 & alt]nat+4 ,x is kn[n t if ^! oscillations are damp$1 s t ! ov]-int5se agitation ( ! c5tral di/urbance is less5$1 a new s]ies ( vibrations1 su* z ! pulsat+ or alt]nat+1 is set up1 & ^! second>y vibrations possess ! p[] to travel ar\nd ! _w--yes1 & p]haps to o!r worlds 9 ! planet>y cosmos4 ,illu/ration3 ,,fig4 #i ,,fig4 #aj ,,fig4 #aa ,,oscillation ,,& ,,vibration ,! /udy ( e!r di/urbances1 wave curr5ts1 oscillat+ curr5ts1 & ! o!r ph5om5a dep5dant ^u ?is invisible =ce is mo/ int]e/+ & fasc9at+1 & 7 x possible to devote m space to ?is topic sev]al *apt]s c\ld be writt5 on ! sci5tific !ory ( wireless telegraphy4#b #b ,= fur!r in=mation on ?is subject ! /ud5t is ref]r$ to su* well-kn[n books z ,signall+ ,across ,space ,)\t ,wires1 by ,pr(4 ,oliv] ,j4 ,lodge1 & ,wireless ,telegraphy1 by ,c4 ,h4 ,sewall4 ,! pr9ciple diff]5ce betwe5 wire1 or l9e1 & wireless telegraphy is t ! ov]head wire1 or und]gr\nd or subm>9e cable1 is omitt$4 ,9 its /ead ! e!r ( ! air is set 9 vibratory motion by prop]ly con/ruct$ in/rum5ts1 & ! communication is record$ at a di/ance by in/rum5ts especially design$ to receive ! transmitt$ waves4 ,x seems to be ! popul> impression t a wireless message s5t f "o po9t to ano!r travels 9 a /raight l9e1 z indicat$ by ,fig4 #aa1 ,b repres5t+ ,bo/on1 :i* receives ! message f ,n4 ,y41 or ,new ,york4 ,z a matt] ( fact1 if sev]al sets ( wireless receiv+ in/rum5ts 7 locat$ on ! circumf]5ce ( a circle ! same di/ance f ,new ,york 9 all directions1 or ev5 at ne>] or f>!r po9ts1 !y w\ld all receive ! same message4 ,in/ead ( travell+ 9 "o direction1 ! e!r waves are set 9 motion by ! electrical di/urbance1 j z wat] is agitat$ by ! /one ?r[n into x4 ,! ripples1 or wavelets1 are />t$ f ! c5tral po9t ( di/urbance & radiate out1 s t in/ead ( rea*+ ,bo/on only ! waves travel ov] e in* ( gr\nd1 or air space1 9 all directions1 & w\ld be record$ 9 e t[n & village )9 ! sph]e ( en]gy set up by ! orig9al =ce t put ! e!r waves 9 motion4 ,! /rong] ?is initial =ce ! wid] its field ( action4 ,?is is %[n at ,fig4 #ab1 :i* is an area compris+ ,philadelphia1 ,pittsburg1 ,buffalo1 ,wa%+ton1 & o!r cities4 ,moreov]1 ! waves ( electrical di/urbance w\ld c>ry f> beyond 9 all directions1 tak+ 9 ! cities ( ! nor?1 s\?1 & we/1 & at ! ea/1 go+ f> out to sea1 beyond ,bo/on h>bor & bel[ ,cape ,hatt]as1 :]e %ips c>ry+ receiv+ in/rum5ts c\ld pick up ! messages4 ,l ! ripples on ! wat]1 ! radiat+ waves1 or r+s1 become l>g] z !y rea* out f>!r & f>!r f ! c5tre ( di/urbance1 until at la/ !y are imp]ceptible1 & lose _! %ape & =ce4 ,illu/ration3 ,,fig4 #ab ,at great di/ances1 !re=e1 ! e!r di/urbance becomes s slight t x is impossible to record ! vibration or message s5t out2 & until "s improv$ =ms ( app>atus & coh]] are inv5t$1 or ! orig9al di/urb+ =ce is enorm\sly increas$1 x w be impossible to s5d messages at long] di/ances ?an f\r or five ?\s& miles f a c5tral po9t4 ,bo? ,m>coni & ,de ,=re/ ass]t t !y are p]fect+ coh]]s :i* w make x possible to girdle ! e>? ) a message1 & t )9 ! next few ye>s an a]ogram may be s5t out f a /ation1 &1 aft] in/antly encircl+ ! e>? & be+ record$ dur+ its passage at all int]m$iate /ations1 x w return & be receiv$ at ! orig9al s5d+-po9t4 ,?is1 ( c\rse1 is a matt] ( future a*ievem5t2 b n[ t messages across ! ,atlantic are a comm]cial fact1 x seems q possible t ! great] feat ( ov]rid+ space & rea*+ any po9t on ! e>?'s surface w soon be a reality4 ,& n[ to proce$ f !ory to ! con/ruction ( a practical wireless app>atus hav+ a radial area ( action ov] "s t5 or fifte5 miles4 ,! pr9cipal p>ts ( a wireless app>atus include ! ant5nas 7or receiv+ & s5d+ poles ) _! t]m9al connections71 ! induction-coil1 /rong prim>y batt]ies or dynamo1 ! coh]] & de-coh]]1 ! telegraph key & s\nd] 7or a telephone receiv]71 & ! necess>y connection wires1 b9d+-po/s1 & gr\nd-plates4 ,a l>ge induction-coil ) _m lay]s ( f9e insulat$ wire w be necess>y = ! p]fect op]ative outfit4 ,! mo/ practical coil = ! amateur is a ,ruhmkorff induction-coil4 7,see ! directions & illu/rations = con/ruct+ ?is coil1 beg9n+ on page #ei ( *apt] iv47 ,! s5d+ app>atus is practically ! same 9 all outfits1 & consi/s ( a s\rce ( electrical en]gy1 su* z a batt]y1 or dynamo1 ! ess5tial induction-coil & adju/able sp>k-gap betwe5 ! brass balls on t]m9al rods1 & ! make-&-break swit*1 or telegraph-key4 ,x is 9 ! v>i\s =ms ( coh]]s & receiv+ app>atus t ! diff]5t inv5tors claim sup]iority & orig9ality4 ,! sy/ems also diff] 9 _! !ory ( h>monic tun+ or vibratory sympa?y4 ,?is is accompli%$ by means ( coils & cond5s]s1 s t ! messages s5t out on "o set ( in/rum5ts w n be pick$ up or record$ by ! receiv+ app>atus ( competitors4 ,hav+ made or pur*as$ an induction-coil ( prop] & adequate size1 x w n[ be necess>y to con/ruct ! p>ts s t an adju/able sp>k-gap may be secur$4 ,make a holl[ wood5 base = ! induction-coil to re/ on4 ,x %\ld be a trifle long] ?an ! l5g? ( ! coil & ab\t sev5 in*es wide4 ,?is may be made f wood half an in* ?ick4 ,! base %\ld be two in*es high1 s t x w be easy & conv5i5t to make wire connections "u x4 ,m\nt ! induction-coil on ! base & make x fa/ ) screws1 arrang+ x s t ! b9d+-po/s are on ! side r ?an at ! top ( ! coil1 z %[n 9 ,fig4 #ac4 ,cut a ?9 bo>d & m\nt x across ! top ( ! induction-coil on two %ort blocks1 & to ?is atta* two d\ble-pole b9d+-po/s 7,p ,p74 ,! f9e wires f ! induction-coil are made fa/ to ! foot ( ea* po/1 & f ! po/s ! a]ial wire 7,a ,w7 & gr\nd wire 7,g ,w7 lead out4 ,fa/5 two b9d+-po/s at ! =w>d corn]s ( ! base1 & to !m make connection-wires fa/ to ! heavy or prim>y wires ( ! coil4 ,wires ,b & ,c lead out f ^! po/s to ! batt]y & key1 & to complete ?is "p ( ! s5d+1 or transmitt+ app>atus x w be necess>y to h two t]m9al rods & balls atta*$ to ! top ( ! b9d+-po/s 7,p ,p74 ,?is "p ( ! app>atus is g5]ally call$ ! oscillator1 & ! rods are balanc$ on ! po/s1 s t !y c be mov$ 9 ord] to increase or dim9i% ! space 7,s ,g71 or sp>k-gap1 betwe5 ! brass balls4 ,:51 aft] exp]im5t1 ! prop] space has be5 det]m9$1 ! set screw at ! top ( ! po/s w hold ! t]m9al rods securely 9 place4 ,obta9 a piece ( brass1 copp]1 or ,g]man-silv] rod ?ree-sixte5?s ( an in* 9 diamet]4 ,n[ cut two %ort rods1 ea* six in*es long1 & two in*es f "o end flatt5 ! rods ) a hamm]1 z %[n at ,a 9 ,fig4 #ad4 ,flatt5 ! rod 9 two places at ! o!r end1 z %[n at ,b ,b 9 ,fig4 #ad2 !n bore holes ?r\gh ! flatt5$ p>ts 7,a71 s t ! b9d+-screws at ! top ( ! po/s 7,p ,p7 w pass ?r\gh !m4 ,obta9 two brass balls f "o to "o in* & a half 9 diamet]4 ,if !y are solid or ca/ brass !y may be atta*$ to ! ends ( ! t]m9al rods by ?read+1 s t x w be easy to remove !m4 ,if ! balls are ( spun %eet-metal x w be necess>y to sold] !m fa/ to ! ends ( ! rods1 &1 :5 poli%+ ! balls1 ! rods w h to be remov$ f ! b9d+-po/s4 ,x is imp]ative t ! balls %\ld be kept poli%$ & 9 bright condition at all times1 to facilitate ! action ( ! impulsive sp>ks4 ,illu/ration3 ,,fig4 #ac ,illu/ration3 ,,fig4 #ad ,to c\nt]balance ^! balls !re %\ld be h&les at ! long ends ( ! rods4 ,^! h&les may be ( wood1 or made ( composition mold$ directly on ! rods4 ,a good composition t c be easily made & mold$ is compos$ ( eight p>ts pla/] ( ,p>is & two p>ts ( dextr9 made into a ?ick pa/e ) wat]4 ,! dextr9 may be pur*as$ at a pa9t-/ore1 & is ! color ( light-br[n sug>4 ,mix ! dry pla/] & dextr9 toge!r1 s t !y are homog5e\s2 !n add wat] to make ! pa/y mass4 ,use an old table-knife to apply ! wet composition to ! b>s4 ,! flatt5$ p>ts w help to hold ! mass 9 place until x sets4 ,x is be/ to make two mixtures ( ! pa/e & put "o on fir/1 leav+ x r\gh on ! surface1 s t ! la/ coat w /ick to x4 ,:5 ! la/ coat is ne>ly dry x may be rubb$ smoo? ) ! f+]s & a little wat]1 or all[$ to dry h>d1 & !n smoo!d d[n ) an old file & s&-pap]4 ,if solid brass balls are us$ = ! t]m9als ! composition h&les may be made heavi]2 b 9 any ev5t ! prop] am\nt ( composition %\ld be us$1 s t :5 ! rod is balanc$ on a nail or piece ( wire pass$ ?r\gh ! hole x w n tip d[n at "o end or ! o!r1 b w rema9 9 a horizontal position4 ,! ov]head "p ( ! app>atus employ$ to collect ! electric waves is call$ ! ant5n1 & 9 ! v>i\s comm]cial =ms ( wireless app>atus ?is feature diff]s4 ,! g5]al pr9ciple1 h[ev]1 is ! same1 & 9 ,figs4 #ae1 #af1 #ag1 & #ah "s simple =ms ( con/ruction are %[n4 ,great c>e mu/ be tak5 to prop]ly insulate ! rod1 wire1 or f+]s ( ^! ant5n1 s t ! full =ce ( ! vibration is c>ri$ directly d[n to ! coh]] & s\nd] or receiv]4 ,= ?is purpose1 porcela91 glass1 or gutta-p]*a knobs mu/ be employ$4 ,9 ,fig4 #ae ! app>atus consi/s ( an upright /ick1 a cross-/ick1 & a brace1 or bracket1 to hold !m 9 prop] place4 ,porcela9 knobs are made fa/ to ! /icks ) l95 /r+ or /\t cotton l9e4 ,!n an insulat$ copp] wire is run ?r\gh ! holes 9 ! knobs1 & f ! out] knob a rod ( brass1 copp]1 or ,g]man-silv]1 or ev5 a piece ( galvaniz$-iron lightn+-rod1 is susp5d$4 ,c>e %\ld be tak5 to see t ! jo9t betwe5 rod & wire is sold]$ s z to make p]fect contact4 ,o!rwise ru/ or corrosion w cause imp]fect contact ( metals1 & int]rupt$ vibrations w\ld be ! result4 ,! upright /ick %\ld be t5 or fifte5 feet high1 & may be atta*$ to a h\se-top1 a *imney1 or on ! corn] ( a b>n ro(4 ,ano!r =m ( s+le ant5na is %[n 9 ,fig4 #af4 ,?is is a rod held fa/ 9 a porcela9 insulator ) cem5t4 ,! insulator1 9 turn1 is slipp$ ov] ! end ( a /aff1 or pole1 :i* is erect$ on a build+ top or out 9 ! op51 ! same z a flag-pole4 ,ne> ! foot ( ! rod1 & j above ! insulator1 a conduct+-wire is made fa/ & sold]$4 ,?is is run d[n ?r\gh porcela9 insulators to ! app>atus4 ,if ! pole is erect$ on a h\se-top x may be brac$ ) wires1 to /ay x1 b c>e mu/ be tak5 n to h ^! wires come into contact ) ! rod1 or conduct+-wire4 ,illu/ration3 ,,fig4 #ae ,,fig4 #af ,,fig4 #ag ,,fig4 #ah ,,types ,,( ,,ant5n ,ano!r =m ( ant5nas is %[n 9 ,fig4 #ag1 :]e rods are susp5d$ f a wire :i*1 9 turn1 is drawn taut betwe5 two insulators4 ,! insulators are held 9 a framework compos$ ( two uprights & a cross-piece ( wood4 ,?is frame may be nail$ fa/ to a *imney & to ! gable ( a ro(1 z %[n 9 ! draw+2 & to /eady ! rods1 s t !y w n sw+ 9 a high w9d1 ! l[] ends %\ld be ti$ toge!r ) cotton /r+1 ! ends ( :i* %\ld be fa/5$ to ! uprights4 ,! lead+-9 wire is made fa/ to ! top wire1 f :i* ! rods are susp5d$1 & all ! expos$ jo9ts %\ld be sold]$ to insure p]fect contact & conductivity4 ,a modifi$ =m ( ! ,m>coni ant5n is %[n 9 ,fig4 #ah4 ,?is is made ( a metal hoop ?ree ( f\r feet 9 diamet] held 9 %ape by cross-/icks ( wood1 :i* c be la%$ fa/ to ! r+4 ,lead+ d[n f x are num]\s copp] wires :i* t]m9ate 9 a s+le wire1 ! :ole app>atus resembl+ a funnel4 ,! upp] unions :]e ! wires jo9 ! r+ ne$ n be sold]$1 b at ! bottom1 :]e !y all come toge!r & jo9 ! lead+-9 wire1 x is q necess>y t a good sold]$ jo9t be made4 ,?is funnel may be hung betwe5 two upright poles on a h\se-top1 or susp5d$ f ! t[]s or *imneys4 ,almo/ any metal plate w d = ! gr\nd1 or ! gr\nd-wire 7,g ,w 9 ,fig4 #ac7 may be b\nd to a gas or wat] pipe :i* goes d[n deep 9 ! gr\nd1 :]e x is moi/4 ,ru/ or :ite lead 9 ! jo9ts ( gas-ma9s sometimes prev5t p]fect contact1 b 9 wat]-pipes ! curr5t w fl[ readily ?r\gh ei!r ! metal or ! wat]4 ,to insure ! mo/ p]fect results1 x is be/ to h an indep5d5t gr\nd compos$ ( metal1 & connect$ directly ) ! oscillator1 or coh]]1 by an insulat$ copp] wire4 ,a simple & easily con/ruct$ gr\nd is a %eet ( metal1 pref]ably copp]1 brass1 or z9c1 to ! upp] edge ( :i* two wires are sold]$1 z %[n 9 ,fig4 #ai4 ,?is is emb$d$ 9 ! gr\nd ?ree or f\r feet bel[ ! surface4 ,ano!r gr\nd-plate is a %eet ( metal b5t 9 ,v %ape & !n inv]t$4 ,two wires are sold]$ to ! angle1 & ! ends br\ght toge!r & sold]$4 ,?is gr\nd is buri$ ?ree or f\r feet deep1 & /&s 9 a v]tical position1 z %[n at ,fig4 #bj4 ,at ,fig4 #ba a flat gr\nd is %[n4 ,?is is a %eet ( metal cut ) po9t$ ends4 ,! gr\nd-wire is sold]$ to ! middle ( x1 & x is !n buri$ deep en\gh to be emb$d$ 9 moi/ e>?4 ,"o ( ! be/ gr\nds is an old broil] ) a copp] wire sold]$ to ! ends ( ! h&les1 z %[n at ,fig4 #bb4 ,?is is buri$ deep 9 ! gr\nd 9 a v]tical position1 & ! insulat$ copp] wire is c>ri$ up to ! in/rum5ts4 ,! mo/ important "p ( ! wireless telegraphic app>atus is n[ to be con/ruct$1 & ?is requires "s c>e & pati5ce4 ,! coh]] is ! delicate1 s5sitive "p ( ! app>atus on :i* h+es success or failure4 ,!re are v>i\s k9ds ( coh]]s design$ & us$ by diff]5t inv5tors1 b :ile ! mat]ials diff] & ! con/ruction takes v>i\s =ms1 ! same basic pr9ciple applies to all4 ,illu/ration3 ,,fig4 #ai ,,fig4 #bj ,,fig4 #ba ,,fig4 #bb ,,types ,,( ,,gr\nds ,! coh]] c be/ be expla9$ z a %ort glass tube 9 :i* iron or o!r metallic fil+s are enclos$4 ,corks are plac$ 9 bo? ends ( ! tube1 & ?r\gh ^! corks ! ends ( wire are pass$1 s t !y occupy ! position %[n 9 ,fig4 #bc1 ! ends be+ sep>at$ a qu>t] ( an in*4 ,metal fil+s w n conduct an electric curr5t ! same z a solid rod or b> ( ! same metal1 b resi/ ! passage ( curr5t4 ,aft] long p]iods ( exp]im5t+ ) v>i\s devices to detect ! pres5ce ( feeble curr5ts1 or oscillations1 9 ! e!r1 ! coh]] ( metal fil+s 0 adopt$4 ,:5 ! oscillations surge ?r\gh ! resonator1 ! pressure1 or pot5tial1 f9ally breaks d[n ! air film sep>at+ ! little p>ticles ( metal1 & !n g5tly welds _! %>p edges & corn]s toge!r s z to =m a conductor = ! curr5t4 ,be=e ?is process ( cohesion takes place ^! f9e p>ticles (f] a v high resi/ance to ! electrical en]gy g5]at$ by a dry cell or batt]y--s mu* s t no curr5t is p]mitt$ to pass4 ,b once ! oscillations 9 ! e!r cause !m to coh]e--pre/o6 ! resi/ance drops f ?\s&s ( ohms to hundr$s1 & ! curr5t f ! dry cell n[ fl[s easily ?r\gh ! coh]] & deflects ! ne$le ( a galvanomet]4 ,?is is ! common pr9ciple ( all coh]]s ( ! granulat$ metal type1 al?\gh !re are _m modifications ( ! idea4 ,! action ( ! electric & oscillatory curr5ts on p>ticles ( metal c be/ be und]/ood by plac+ "s f9e iron fil+s on a bo>d1 z %[n at ,fig4 #bd1 & !n ins]t+ ! a]ial & gr\nd wires 9 ! fil+s1 b sep>at$ by an eigh? or a qu>t] ( an in*4 ,a tempor>y connection may be made z %[n 9 ,fig4 #be4 ,illu/ration3 ,,fig4 #bc ,illu/ration3 ,,fig4 #bf ,illu/ration3 ,,fig4 #bg ,illu/ration3 ,,fig4 #bd ,illu/ration3 ,,fig4 #be ,a ,a are a]ials on bo? in/rum5ts2 ,c is ! op5 coh]]1 or bo>d ) iron fil+s1 9 :i* ! ends ( ! a]ial & gr\nd wires are emb$d$2 ,d ,c is a dry cell2 & ,r is a telegraphic relay1 or s\nd]4 ,if ! wire across ,c 0 n p>t$ & cov]$ ) fil+s1 ! dry cell w\ld op]ate ,r1 b ! high resi/ance ( ! p>ticles ( metal holds back ! curr5t4 ,on ! opposite side1 ,i ,c is ! induction-coil2 ,k is ! telegraphic key1 or swit*1 :i* makes & breaks ! curr5t2 ,s ,b is ! /orage-batt]ies1 or s\rce ( electric en]gy2 & ,s ,g ! sp>k-gap betwe5 ! brass balls on ! t]m9al rods4 ,by clos+ ! circuit at ,k ! curr5t fl[s ?r\gh ! prim>y ( ! induction-coil1 affects ! second>y coil1 & causes a sp>k to leap across ! gap betwe5 ! brass balls4 ,?is in/antly sets ! e!r 9 motion f ,a on ! "r1 & ! impulse is pick$ up by ,a on ! left4 ,?is oscillation breaks d[n ! resi/ance ( ! fil+s at ,c1 & ! curr5t f batt]y1 or dry cell 7,d ,c71 fl[s ?r\gh ! fil+s & op]ates ! s\nd]1 or relay 7,r74 ,?is op]ation takes place in/antly1 & ! p>ticles ( metal are se5 to coh]e1 or %ift1 s t bett] contact is e/abli%$4 ,b z soon z ! sp>k has jump$ across ! gap ! action ( cohesion ceases until ! key 7,k7 is aga9 op]at$ to close ! circuit & cause ano!r sp>k to leap across ! gap4 ,! %ift+ ( ! metal p>ticles on ! bo>d 7,c7 is :at takes place 9 ! glass tube ( ! coh]]1 ,fig4 #bc1 b 9 ?is conf9$ space ! p>ticles w n drop ap>t aga9 z on ! flat surface1 b w cont9ue to coh]e4 ,a de-coh]] is necess>y1 !re=e1 to knock ! p>ticles ap>t1 s t ! next oscillatory impulse w h a /rong & individual effect4 ,!re are sev]al =ms ( de-coh]]s 9 use1 b = ! amateur telegraph] an electric-bell movem5t )\t ! bell1 or1 9 o!r words1 a buzz] ) a knock] on ! armature1 w answ] e purpose4 7,see description ( buzz] on page #fd47 ,x mu/ be prop]ly m\nt$1 s t on its back /roke1 or reb\nd1 ! knock] w /rike ! glass tube & %ake ! p>ticles ( metal ap>t4 ,= ?is purpose ! vibrations ( ! armature %\ld be s regulat$ z to obta9 ! greate/ possible spe$1 9 ord] t ! dots & da%es 7or %ort & long p]iods7 w be accurately record$ ?r\gh ! coh]] & made audible by ! s\nd] or telephone receiv]4 ,ano!r =m ( coh]] is %[n 9 ,fig4 #bf4 ,?is is made ( a small piece ( glass tube1 two rods t w accurately fit 9 ! tube1 "s nickel fil+s1 two b9d+-po/s1 & a base-block ?ree in*es & a half long4 ,! two b9d+-po/s are m\nt$ on ! block1 & ?r\gh ! holes 9 ! body ( ! po/s ! rods are slipp$4 ,!y pass into ! tube1 & ! blunt ends press ! small mass ( fil+s toge!r1 z %[n 9 ! draw+4 ,by means ( ! b9d+-po/s ^! coh]]-rods may be held 9 place & ! prop] pressure aga9/ ! fil+s adju/$2 !n ma9ta9$ by ! set-screws4 ,! nickel fil+s may be procur$ by fil+ ! edge ( a five-c5t piece4 ,obta9 a few fil+s f ! edge ( a dime & add !m to ! nickel1 s t ! mixture w be 9 ! proportion ( "o "p silv] to n9e p>ts nickel4 ,?is mixture w be f\nd to "w bett] ?an ! iron fil+s alone4 ,! a]ial & gr\nd wires are made fa/ to ! foot-screws ( ! b9d+-po/s1 & ! base on :i* ! coh]] is m\nt$ may be atta*$ to a table or l$ge on :i* ! o!r p>ts ( ! receiv+ & record+ app>atus are also in/all$4 ,ano!r =m ( coh]] is %[n at ,fig4 #bg4 ,?is is con/ruct$ 9 a some:at simil> mann] to ! "o j describ$4 ,a glass tube is provid$ ) two corks hav+ holes 9 !m to receive ! coh]]-rods4 ,two plugs ( silv] are arrang$ to accurately fit )9 ! tube1 & into ^! ! ends ( ! coh]]-rods are screw$ or sold]$4 ,betwe5 ^! silv] plugs1 or t]m9als1 ! fil+s ( nickel & silv] are plac$1 & ! rods are pu%$ toge!r & caught 9 ! b9d+-po/s4 ,! a]ial & gr\nd wires are made fa/ to ! foot-screws ( ! po/s4 ,= long-di/ance communication x is necess>y to h a cond5s] plac$ 9 s]ies ) ! sp>k+ or s5d+-out app>atus4 7,see ! type ( cond5s] describ$ & illu/rat$ 9 *apt] iv41 page #gb47 ,an a/atic galvanomet] is also a valuable "p ( ! receiv+ app>atus1 & ! "o describ$ on page #aaa w %[ cle>ly ! pres5ce ( oscillatory curr5ts by ! rapid & s5sitive deflections ( ! ne$le4 ,= local s]vice1 :]e a mod]ately p[]ful batt]y is employ$1 a telegraph-key1 su* z describ$ on page #aij1 w answ] v well1 b = high-t5sion "w1 :]e a p[]ful /orage-batt]y or small dynamo is employ$1 x w be necess>y to h a non-sp>k+ key1 s t ! direct curr5t w n =m an arc betwe5 ! t]m9als ( a key4 ,mo/ ( ! keys us$ = wireless telegraphy h high insulat$ pressure-knobs1 or ! make & break is done 9 oil1 s t ! sp>k or arc _c jump or be =m$ betwe5 ! po9ts4 ,! plan ( a simple non-sp>k+ dry swit* is %[n at ,fig4 #bh4 ,?is is built up on a block ?ree in*es wide & five in*es long4 ,x consi/s ( a b> 7,a71 two spr+ int]rupt]s 7,b & ,c71 a spr+ 7,d71 & ! b9d+-po/s 7,e ,e74 ,!y are arrang$ z %[n 9 ,fig4 #bh1 & a front elevation is giv5 9 ,fig4 #bi4 ,! /rip 7,b7 lies flat on ! block1 & is connect$ ) "o b9d+-po/ by a wire atta*$ "u "o screw-head & run along ! "u side ( ! base 9 a groove to ! foot ( ! po/4 ,/rip ,c is ( spr+-brass1 & is made fa/ to ! base ) screws4 ,?is is 8dead10 z no curr5t passes ?r\gh x1 & its only use is to int]rupt4 ,! b> 7,a7 is arrang$ z expla9$ = ! l9e telegraph-key1 & ! rema9+ b9d+-po/ is connect$ to x by a wire run "u ! base & br\ght up to "o ( ! angle-pieces =m+ ! h+e4 ,a high wood or porcela9 knob is made fa/ at ! =w>d end ( ! b>1 s t :5 high-t5sion curr5t is employ$ ! sp>k w n jump f ! b> to ! op]ator's h&4 ,! complete key ready = op]ation is %[n at ,fig4 #cj1 & to make x p]man5t x %\ld be screw$ fa/ to ! table1 or cab9et1 on :i* ! coil & cond5s] re/4 ,! plan ( a 8wet0 key is %[n 9 ,fig4 #ca1 & ! complete key 9 ,fig4 #cb4 ,illu/ration3 ,,fig4 #bh ,,fig4 #bi ,,fig4 #cj ,,fig4 #ca ,,fig4 #cb ,,dry ,,& ,,wet ,,non-,,sp>k+ ,,swit*es ,a base ( wood ?ree by five in*es is made & giv5 sev]al coats ( %ellac4 ,obta9 a small rubb] or composition pill or salve box1 & make x fa/ to ! front end ( ! base ) an oval-head$ brass screw driv5 d[n ?r\gh ! c5tre ( ! box4 ,a wire lead+ to "o b9d+-po/ is arrang$ to come into contact ) ! screw1 & ! o!r po/ is connect$ by wire to "o h+e-plate support+ ! b>4 ,! long ma*9e screw1 or rivet1 pass$ d[n ?r\gh ! knob & into ! b>1 ext5ds d[n bel[ ! b> = half an in* or m1 s t :5 ! knob is press$ d[n ! end ( ! screw1 or rivet1 w /rike ! top ( ! screw at ! bottom ( ! box )\t ! b> com+ 9 contact ) ! edge ( ! box4 ,:5 9 op]ation ! composition box is fill$ ) olive oil or ?9 ma*9]y oil1 s t :5 contact is made by press+ ! knob d[n ! circuit w be in/antly brok51 ! spr+ at ! re> end ( ! b> draw+ x back to re/4 ,! oil prev5ts any sp>ks jump+ across2 & also breaks an arc1 %\ld "o =m betwe5 ! contact-po9ts4 ,) ! addition ( a good /orage-batt]y 7! /r5g? ( :i* mu/ be gov]n$ by ! size ( ! induction-coil & ! di/ance ! messages are s5t7 & a dry-cell or two = ! receiv+ app>atus1 ! p>ts ( ! wireless app>atus are n[ ready = assembl+4 ,full directions = mak+ /orage-cells is giv5 9 *apt] ii41 page #ba1 & = dry-cells 9 *apt] ii41 page #bi4 ,= %ort-di/ance "w ! plan %[n 9 ,figs4 #cc & #cd w be f\nd a v satisfactory =m ( app>atus4 ,"o ( ea* k9d ( in/rum5t %\ld be at e po9t :]e communication is to be e/abli%$4 ,9 ! s5d+ app>atus 7,fig4 #cc7 ,s ,c are ! /orage-cells1 ,k ! key1 & ,i ,c ! induction-coil4 ,t ,t are ! t]m9als & balls1 ,s ,g ! sp>k-gap1 & ,p ,p ! po/s t hold ! t]m9al rods4 ,a ,w is ! a]ial wire runn+ up f "o po/1 & ,g ,w ! gr\nd-wire connect+ ! o!r t]m9al po/ ) ! gr\nd-plates4 ,9 ! receiv+ app>atus 7,fig4 #cd7 ,c is ! coh]]1 ,d ,c ! de-coh]]1 ,t ,s ! telegraphic s\nd]1 or relay1 & ,a ,g ! a/atic galvanomet]4 ,b is ! dry-cell1 or batt]y1 & ,d ,c ,s ! de-coh]] swit*1 s t :5 ! app>atus is n 9 use ! dry-cell w n op]ate ! buzz] or de-coh]]4 ,a ,w is ! a]ial wire & ,g ,w ! gr\nd-wire4 ,two or m /orage-cells may be connect$ 9 s]ies 7t is1 ! negative ( "o ) ! positive pole ( ! o!r7 until a suffici5tly p[]ful s\rce ( curr5t is secur$ = ! transmission ( messages4 ,illu/ration3 ,,fig4 #cc ,illu/ration3 ,,fig4 #cd ,to op]ate ! app>atus1 ! circuit is clos$ ) ,k1 & ! curr5t f ,s ,c fl[s ar\nd ! prim>y coil 9 ,i ,c & affects ! second>y coil1 caus+ ! sp>k to leap across ! gap 7,s ,g74 ,?is causes a di/urbance ?r\gh ! wires ,a ,w & ,g ,w1 & ! e!r waves are set 9 oscillatory motion f ! ant5n on ! h\se-top4 ,?is affects ! ant5n at ! receiv+-po9t1 & ! impression is record$ ?r\gh ! coh]] 7,c7 on ! telegraphic s\nd] or relay 7,t ,s71 :i* is op]at$ by ! curr5t f dry-cell or batt]y 7,b71 s9ce ! oscillations h brok5 ! resi/ance ( ! fil+s 9 ! coh]] 7,c74 ,! in/ant t ! curr5t passes ?r\gh ! coh]] & op]ates ,t ,s1 ! a/atic galvanomet] indicates ! pres5ce ( curr5t by ! deflect$ ne$le4 ,illu/ration3 ,,fig4 #ce ,:5 ! app>atus is 9 op]ation ,d ,c ,s is clos$1 s t ! curr5t f ,b op]ates ! coh]] 7,d ,c74 ,directly communication is brok5 (f1 ! swit* 7,d ,c ,s7 %\ld be op5$2 o!rwise ! buzz] w\ld keep up a cont9u\s tapp+4 ,= long-di/ance "w a m effici5t s5d+ app>atus is %[n 9 ,fig4 #ce4 ,?is is compos$ ( an induction-coil1 ) ! t]m9al rods & brass balls =m+ ! sp>k-gap1 an oil key 7,k71 & ?ree or m l>ge /orage-cells1 or a dynamo 7if p[] c be _h to run x74 ,a cond5s] is plac$ 9 connection ) ! a]ial & gr\nd wires1 s t add$ int5sity or high] voltage is giv5 ! sp>k z x leaps across ! gap4 ,9 op]ation ?is app>atus is simil> to ! "o already describ$4 ,:]e contact is made ) ,k ! prim>y coil is *>g$1 & by induction ! curr5t affects ! second>y coil1 ! curr5t or high voltage f :i* is /or$ 9 ! cond5s]4 ,:5 a suffici5t quantity is accumulat$ ! sp>k leaps across ,s ,g & affects wires ,a ,w & ,g ,w4 ,?is action is almo/ in/antane\s1 & directly ! impulse sets ! e!r 9 motion ! same impulse is record$ on ! di/ant coh]]s & s\nd]s4 ,!re are a great _m modifications ( ?is app>atus1 b ! pr9ciples are practically ! same1 & :ile ! con/ruction ( ?is app>atus is )9 ! ability ( ! av]age boy1 _m ( ! m complicat$ =ms ( coh]]s & o!r p>ts w\ld be beyond 8 k & skill4 ,m>coni has realiz$ 8 ambition to s5d messages across ! ocean )\t wires1 & is n[ do+ s on a comm]cial basis1 & at ! rate ( tw5ty-five words a m9ute4 ,x is b ! next /ep to e/abli% communication half-way ar\nd ! _w1 & f9ally to girdle ! e>?4 ,*apt] ,x ,,dynamos ,,& ,,motors ,to adequately treat ( dynamos & motors1 a good-siz$ book r ?an ?is s+le *apt] w\ld be necess>y1 & only a g5]al survey ( ! subject is possible4 ,its importance is unque/ionable2 inde$1 ! :ole sci5ce ( appli$ electricity dates f ! inv5tion ( ! dynamo4 ,)\t me*anical production ( electricity !re c\ld be no su* ?+ z electric traction1 heat1 light1 p[]1 & electro-metallurgy1 s9ce ! *emical g5]ation ( electricity is f> too exp5sive = comm]cial use4 ,surely x is a "p ( ord9>y education n[adays to h a cle> & def9ite idea ( ! pr9ciples ( electrical sci5ce1 & 9 no dep>tm5t ( human k has !re be5 m con/ant & rapid advance4 ,x is only a truism to ass]t t ! s*ool-boy ( to-day kn[s a hundr$fold m ab\t electricity & its v>i$ ph5om5a ?an did ! sci5ti/s & philosoph]s ( old--,volta & ,galvani & ,b5jam9 ,frankl94 ,yet x 0 = ^! =]unn]s to op5 & blaze ! way = o!rs to foll[4 ,a beg9n+ mu/ always be made1 & ! ,m>conis & ,edisons ( to-day are glad to ackn[l$ge _! indebt$ness to ! exp]im5t]s & inv5tors ( ! pa/4 ,& n[ to our subject4 ,all dynamos are con/ruct$ on practically ! same pr9ciple--a field ( =ce rapidly & cont9u\sly cutt+ ano!r field ( =ce1 & s g5]at+ electric curr5t4 ,! common practice 9 all dynamos & motors is to h ! armature fields revolve )91 or cut ! =ces ( ! ma9 fields ( ! app>atus4 ,!re are _m diff]5t k9ds ( dynamos g5]at+ z _m v>ieties ( curr5t--curr5ts ) high voltage & l[ amp]age2 curr5ts ) l[ voltage & high amp]age2 curr5ts direct = light+1 heat+1 & p[]2 curr5ts alt]nat+1 = high-t5sion p[] or transmission1 electro-metallurgy1 & o!r uses4 ,x is n ! int5tion 9 ?is *apt] to review all ( ^! =ms1 nor to expla9 ! complicat$ & intricate sy/ems ( w9d+ fields & armatures = special purposes4 ,consequ5tly1 only a few ( ! simpl] =ms ( g5]ators & motors w be "h describ$1 leav+ ! m complex problems = ! consid]ation ( ! advanc$ /ud5t4 ,= 8 use a li/ ( practical text-books is app5d$ 9 a foot-note4#c #c ,fir/ ,pr9ciples ( ,electricity & ,magnetism1 by ,c4 ,h4 ,w4 ,biggs2 ,! ,dynamo3 ,h[ ,made & ,us$1 by ,s4 ,r4 ,bottone2 ,dynamo ,electric ,ma*9]y1 by ,pr(essor ,s4 ,p4 ,?ompson2 ,practical ,dynamo ,build+ = ,amateurs1 by ,fr$]ick ,walk]4 ,! ,uni-direction ,dynamo ,! uni-direction curr5t ma*9e is ab\t ! simple/ practicable dynamo t a boy c make4 ,x may be op]at$ by h&1 or c be run by motive p[]4 ,! field is a p]man5t magnet simil> to a horse%oe magnet4 ,?is mu/ be made by a blacksmi?1 b if a l>ge p>allel magnet c be pur*as$ at a reasonable price s mu* ! bett]1 z "t & tr\ble w be sav$4 ,?is magnet %\ld measure t5 in*es long & f\r in*es & a half across1 ) a cle> space sev5 in*es long & "o in* & ?ree-qu>t]s wide1 inside measure4 ,! metal %\ld be half an in* ?ick & "o in* & a qu>t] wide4 ,a blacksmi? w make & temp] ?is magnet =m2 !n1 if !re is a p[]-/ation ne> at h& :]e electricity is g5]at$ = traction or light+ purposes1 "o ( ! workm5 w magnetize x = y at a small co/2 or x c be w\nd ) sev]al coils ( wire1 "o ov] ! o!r1 & a curr5t run ?r\gh x4 ,:5 prop]ly magnetiz$ x %\ld be p[]ful en\gh to raise t5 p\nds ( iron4 ,?is may be te/$ by %utt+ (f ! curr5t & try+ its lift+ p[]4 ,if ! magnet is too weak to attract ! weight ! curr5t %\ld be turn$ on & ano!r te/ made a few m9utes lat]4 ,be=e ! /eel is temp]$ !re %\ld be f\r holes bor$ 9 ! magnet & c\nt]sunk1 s t screws may be pass$ ?r\gh x & into ! wood5 base bel[1 z %[n at ,fig4 #a4 ,?is wood5 base is f\rte5 in*es long1 eight in*es wide1 & "o in* 9 ?ickness4 ,x may be made ( p9e1 :ite-wood1 bir*1 or any good dry wood t may be at h&4 ,! blocks on :i* ! magnet re/s are an in* & a qu>t] squ>e & sev5 in*es long4 ,! magnet is m\nt$ directly 9 ! middle ( ! base1 an equal di/ance f bo? edges & ends1 z %[n 9 ! plan draw+ 7,fig4 #aj74 ,! blocks are atta*$ ) glue & brass screws driv5 up f ! und]side ( ! base4 ,f a brass /rip ?ree-eigh?s ( an in* wide & "o-eigh? ( an in* ?ick cut a piece six in*es long1 & bore holes at ei!r end ?r\gh :i* long1 slim1 oval-head$ brass screws may pass4 ,use brass1 copp]1 or ,g]man-silv] = ?is b>1 & n iron or /eel4 ,to ! und]side1 & at ! middle1 sold] or screw fa/ a small block ( brass1 ?r\gh :i* a hole is to be bor$ = ! sp9dle or %aft4 ,?is f9i%$ b> is %[n 9 ,fig4 #b4 ,:5 m\nt$ ov] ! magnet & held d[n ) brass screws driv5 into ! wood base1 its end view w appe> z %[n 9 ,fig4 #c1 ,a be+ ! b>1 ,b ,b ! screws :i* hold x d[n1 ,d ! base into :i* !y are driv51 & ,c ,c ! blocks "u ! magnet 7,n ,s74 ,! object ( ?is b> is to support "o end ( ! armature %aft4 ,f brass "o-eigh? ( an in* ?ick b5d & =m two angles1 z %[n at ,fig4 #d4 ,two holes = screws are to be drill$ 9 ! "p t re/s on ! base1 & "o hole1 = ! %aft to pass ?r\gh1 is bor$ ne> ! top ( ! upright plate4 ,! c5tre ( ?is la/ hole mu/ be ! same height f ! base z is ! hole 9 ! b> 7,fig4 #b7 :5 m\nt$ ov] ! magnet1 z %[n at ,fig4 #c4 ,! location ( ^! plates is %[n 9 ! plan 7,fig4 #aj74 ,!re is "o plate at ea* end ( ! base1 z indicat$ at ,b & ,b ,b1 ! %aft pass+ ?r\gh ! hole 9 ! brass block at ! und]side ( ! b> 7,c74 ,^! angles are ! end-be>+s = ! armature %aft1 & %\ld be accurately c5tr$ s t ! armature w be prop]ly c5tr$ betwe5 ! ,n & ,s b>s ( ! magnet4 ,illu/ration3 ,,fig4 #a ,,fig4 #b ,,fig4 #c ,,fig4 #d ,,fig4 #e ,,fig4 #f ,,fig4 #g ,,fig4 #h ,,fig4 #i ,,details ,,( ,,uni-,,direction ,,dynamo ,! armature is made f s(t1 r\nd iron rod "o in* & a half 9 diamet] & five in*es long4 ,a *annel is cut all ar\nd x1 l5g?wise1 five-eigh?s ( an in* wide & half an in* deep1 z %[n 9 ,fig4 #e4 ,?is w h to be done at a ma*9e-%op 9 a %ort b$-plan]1 s9ce x w\ld be a long & t$i\s job to cut x out ) a hack-saw4 ,! %>p corn]s %\ld be r\nd$ (f f ! c5tral lug1 s t !y w n cut ! /r&s ( f9e wire t are to be w\nd r\nd x4 ,two brass disks1 or wa%]s1 are to be cut1 "o in* & a half 9 diamet] & f "o-eigh? to "o-qu>t] ( an in* ?ick1 = ! armature ends4 ,a qu>t]-in* hole is to be made 9 ! c5tre ( ea* = ! %aft to fit 91 & two small] holes mu/ be drill$ ne> ! edge1 & opposite ea* o!r1 s t ma*9e-screws may pass ?r\gh !m & into holes bor$ & ?read$ 9 ! ends ( ! armature1 z %[n at ,fig4 #e4 ,^! ends w appe> z %[n at ,fig4 #f1 & ! middle hole %\ld be ?read$ s z to receive ! end ( a %aft4 ,:5 ! %aft is screw$ 9 tight ! end t passes ?r\gh ! brass disk mu/ be tapp$ ) a light hamm] to rivet ! end1 & s insure t ! %aft w n unscrew4 ,! %afts %\ld be ( h>d brass or ( /eel4 ,! "o at ! front %\ld be "o in* & a half 9 l5g?1 & t at ! re> six in*es long1 measur+ f ! out] face ( ! brass end to ! end ( ! %aft4 ,f boxwood or maple turn a cyl9d] ?ree-qu>t]s ( an in* 9 diamet] & an in* long1 ) a qu>t]-in* hole ?r\gh x4 ,ov] ?is slip a piece ( ?ree-qu>t]-in* brass or copp] tub+ t fits snugly1 & at opposite sides drill holes & drive 9 %ort screws t w hold ! tube fa/ to ! hub4 ,!y mu/ n be s long z to rea* ! hole ?r\gh ! c5tre4 ,place ?is hub 9 a vise1 & ) a hack-saw cut ! tube across 9 two opposite places1 s t y w h ! cyl9d] ) two half-circul> %ells or commutators screw$ fa/ to x1 z %[n at ,fig4 #g4 ,?is hub w fit ov] ! %aft at ! front end ( ! armature1 & w occupy ! position %[n at ,f 9 ,fig4 #aj4 ,cut two small blocks ( wood = ! bru%es & b9d+-po/s1 & bore a hole ?r\gh !m1 s t ! foot-screw ( a b9d+-po/ may pass ?r\gh ! block & into ! po/1 z %[n at ,fig4 #h4 ,f ?9 spr+ copp] cut a n>r[ /rip & b5d x ov] ! block1 cat*+ x at ! top ) a screw & lapp+ x "u ! b9d+-po/ at ! outside4 ,f boxwood or maple h a small wood5 pulley turn$1 ) a groove 9 x & a qu>t]-in* hole ?r\gh ! c5tre4 ,?is pulley %\ld be half an in* wide & "o in* & a half 9 diamet]1 z %[n at ,fig4 #i4 ,?is is to be atta*$ at ! end ( ! long %aft1 :]e x w occupy ! position %[n at ,e 9 ,fig4 #aj4 ,all ! p>ts are n[ ready = assembl+ except ! armature1 :i* mu/ be w\nd4 ,be=e lay+ on ! turns ( wire ! *annel 9 ! iron mu/ be l9$ ) silk1 held 9 place ) glue or %ellac4 ,a b& ( silk ribbon is giv5 two turns ab\t ! c5tre ( ! iron1 & ! sides are s completely cov]$ ) silk t n a s+le /r& ( wire w come into direct contact ) ! iron4 ,great c>e mu/ be tak51 :5 w9d+ on ! wire1 n to k9k1 *afe1 or "p ! /r&s4 ,! *annel %\ld be fill$ b n ov]cr[d$1 & :5 full sev]al wraps ( insulat+ tape %\ld be made fa/ ab\t ! armature to hold ! wire firmly 9 place & prev5t x f work+ out at ! c5tre :5 ! armature is driv5 at high spe$4 ,! armature1 :5 prop]ly w\nd & wrapp$1 w appe> z %[n at ,a 9 ,fig4 #aa1 & x is !n ready to h ! ends screw$ on4 ,sev]al sizes ( wire may be us$ to w9d ! armature1 accord+ to ! curr5t desir$1 b = g5]al use x w\ld be well to use ,no4 #cj silk-insulat$ copp] wire4 ,illu/ration3 ,,fig4 #aj ,,fig4 #aa ,,plan ,,( ,,! ,,uni-,,direction ,,dynamo ,ab\t f\r ounces %\ld be en\gh = ?is armature1 & ! ends are to be pass$ ?r\gh small holes 9 ! brass end 7,b72 see ,fig4 #aa4 ,"o end mu/ be sold]$ to "o commutator1 ! o!r end to ! o!r commutator4 ,! end-piece 7,b7 is atta*$ to ! iron armature 7,a7 ) ma*9e-screws2 !n ,c is to be made fa/ 9 a simil> mann]4 ,:5 putt+ ! p>ts toge!r1 x w\ld be well to use "s %ellac on ! wood5 cyl9d] & driv+-:eel to make !m hold to ! %aft4 ,by foll[+ ! plan 9 ,fig4 #aj1 x w be an easy matt] to put ! p>ts toge!r2 :5 !y are assembl$ ! complete ma*9e w appe> z %[n 9 ! draw+ 7,fig4 #ab74 ,! driv+-:eel %\ld be ( wood five-eigh?s ( an in* ?ick & six in*es 9 diamet]1 & held 9 ! frame ( wood & metal brackets by a bolt4 ,a %ort h&le c be arrang$ ) :i* to turn ! :eel1 & a small lea!r belt w transmit ! p[] to ! small :eel on ! armature %aft4 ,z ! armature is revolv$ ! l9es ( =ce are cut & ! curr5t is c>ri$ out ?r\gh ! wire atta*$ to ! b9d+-po/s on ! blocks 7,g ,g74 ,illu/ration3 ,,fig4 #ab ,consid]able curr5t may be g5]at$ if ! armature is driv5 at high] spe$ ?an ! h&-:eel w cause x to revolve4 ,?is c be accompli%$ by runn+ ! belt ov] a l>g] :eel1 su* z ! fly-:eel ( a sew+-ma*9e1 or connect+ x to a l>ge pulley on a wat]-motor4 ,! latt] may be atta*$ to a faucet 9 ! wa%-tub if !re is pressure en\gh to d ! "w4 ,a ,small ,dynamo ,all dynamos are con/ruct$ on ! same g5]al pr9ciple z t ( ! uni-direction ma*9e j describ$2 b !y diff] 9 _! w9d+s1 ! quantities ( metal electrifi$1 ! sizes & l5g?s ( wire w\nd on bo? armature & field1 & 9 _! %ape & spe$s4 ,9 l>ge dynamos x is impossible to employ /eel magnets ( ! requir$ size4 ,9 place ( !m s(t iron cores are us$ & magnetiz$ by ext]nal electric curr5t2 or ! wir+ is done 9 8s]ies0 or 8%unt10 s t ! fields w be self-excit+ once ! ma*9e has be5 prop]ly />t$4 ,! pr9cipal diff]5ce 9 dynamos is1 p]haps1 m cle>ly illu/rat$ by ! diagrams %[n 9 ,figs4 #ac1 #ad1 #ae1 & #af4 ,9 ,fig4 #ac ! arrangem5t ( armature & field-magnet is ! same z 9 ! uni-direction ma*9e1 ! field 7,f7 be+ ( magnetiz$ /eel1 :ile ! armature 7,a7 is ( s(t iron w\nd ) coils ( f9e wire1 ! ends ( :i* are br\ght out at ! commutators 7,c71 ?r\gh :i* ! curr5t is c>ri$ to ! bru%es 7,b & ,b ,b74 ,if1 h[ev]1 ! s(t iron cores are us$1 a sep>ate magnetiz+ electric curr5t mu/ be pass$ ?r\gh ! coils ( wire w\nd ab\t ! field-pieces1 s t !y w become tempor>y magnets--! same z ! cores ( an electric bell movem5t1 a telegraph-s\nd]1 or ! induction-coil core :5 a curr5t is pass$ ?r\gh ! prim>y coil4 ,! armature 7,a7 is !n driv5 at high spe$ by p[]1 & ! curr5t is tak5 (f = use ?r\gh wires t lead f ,b & ,b ,b4 ,9 all ( ^! figures ! armatures rotate1 9 ! space betwe5 ! l>ge pole-pieces ( ! field-magnets1 9 ! same direction z ! h&s ( a clock move4 ,9 ^! figure draw+s ! field-magnets1 commutators1 & bru%es only are %[n1 ! armature be+ indicat$ by ! circle 7,a74 ,figure #ac repres5ts a dynamo1 ! field-magnets ( :i* are excit$ by a sep>ate batt]y or g5]ator4 ,?is is kn[n z a 8sep>ately excit$0 ma*9e1 & is employ$ = v>i\s uses4 ,! bru%es 7,b & ,b ,b7 are connect$ to ! ext]nal circuit--t is1 ) ! motor or o!r app>atus = :i* curr5t is to be g5]at$4 ,! magnetic field 9 :i* ! armature rotates w be con/ant if ! excit+ curr5t is con/ant1 l ! magnetism 9 ! magnet ( ! uni-direction curr5t ma*9e4 ,! induc$ electro-motive =ce 7:i* dep5ds ^u ! rate at :i* ! l9es ( =ce are cut7 w be con/ant = ! giv5 spe$ at :i* ! armature rotates4 ,?is action is ! same z t describ$ = ! uni-direction curr5t ma*9e4 ,figure #ad is ! diagram ( a 8s]ies0-w\nd dynamo4 ,! field & armature are s(t gray iron1 & are w\nd 9 s]ies--t is1 "o end ( ! magnet-w9d+ is made fa/ to ! bru% ,b1 ! o!r to ! bru% ,b ,b1 & ! app>atus to be op]at$ by ! curr5t is let 9 betwe5 ,b ,b & ! magnet1 z %[n by ! indicat$ electric arc-light 9 ! illu/ration4 ,! field-magnet coils1 ! armature1 & ! ext]nal conductors are 9 s]ies ) ea* o!r1 =m+ a simple circuit4 ,:5 ! armature is driv5 at high spe$ ! field-magnets become self-excit+1 ) ! result t curr5t is g5]at$4 ,its simple c\rse is ?r\gh ,b ,b to commutators on ! hub1 !nce ?r\gh "o w9d+ on ! iron armature ,a1 to ,b1 ?r\gh field ,f1 & back to ,b ,b aga91 op]at+ 9 its c\rse any pieces ( equipm5t design$ = electric impulse1 su* z motors1 or lamps1 trolley-c>s1 tra9s1 or electric ma*9]y4 ,illu/ration3 ,,fig4 #ac ,illu/ration3 ,,fig4 #ad ,illu/ration3 ,,fig4 #ae ,illu/ration3 ,,fig4 #af ,! ?ird type1 %[n 9 ,fig4 #ae1 is kn[n z 8%unt0-w9d+4 ,! field-magnet coils & ! ext]nal resi/ance are 9 p>allel1 or %unt ) ea* o!r1 in/ead ( 9 s]ies4 ,! bru%es are connect$ ) ! ext]nal circuit1 & also ) ! ends ( ! field-magnet coils4 ,?is is cle>ly %[n 9 ! draw+4 ,! ends ( ! field-coils are connect$ ) bru%es ,b & ,b ,b1 & ! ext]nal circuit wires are connect$ also ) ! same bru%es1 & pass d[n to su* an app>atus z a plat+ ba?1 9 :i* ! curr5t runs ?r\gh ! electrode1 ! electrolyte1 & ! ca?ode1 mo/ ( ! curr5t g5]at$ pass+ ?r\gh ! ext]nal circuit4 ,! field-coils are ( f9e wire1 & :5 ! armature is rotat$ !re w always be a curr5t ?r\gh ! field-magnets1 :e!r ! ext]nal circuit is complete or n4 ,if a break occurs 9 ! ext]nal circuit1 a m p[]ful curr5t w consequ5tly pass ?r\gh ! field-magnets4 ,9 ,fig4 #af a 8comp\nd0-w\nd dynamo is %[n4 ,x is a comb9ation ( ! s]ies & ! %unt ma*9e4 ,! field-magnet coils are compos$ ( two sizes ( wire4 ,!re are comp>atively f\r turns ( /\t wire & _m turns ( f9e wire1 ! ends ( bo? be+ connect$1 z %[n 9 ! draw+4 ,! /\t wire leads out to lamps :i* are arrang$ 9 s]ies1 z %[n at ! foot ( ! draw+4 ,! curr5t develop$ by ?is dynamo is "o ( 8con/ant pot5tial10 & is us$ almo/ exclusively = inc&esc5t lamps1 ! 8con/ant0 curr5t f ! s]ies-w\nd ma*9e be+ us$ = arc-lamps1 p[]1 & o!r comm]cial purposes4 ,x w n be necess>y to use ! fir/ or la/ sy/ems1 nor to exp]im5t ) ! alt]nat+ curr5t1 ) its phases & cycles4 ,all t a boy wants is a good direct-curr5t ma*9e t w light lamps1 run sew+-ma*9es or motors1 & furni% ! p[] = long-di/ance wireless telegraphy & o!r app>atus requir+ consid]able curr5t4 ,to beg9 )1 x w\ld be bett] to make a small dynamo & /udy its pr9ciples z y progress2 !n x w be a great deal easi] to con/ruct a l>g] "o4 ,x w be necess>y to h ! iron p>ts made at a blacksmi?-%op1 s9ce ! v>i\s cutt+1 ?read+1 & tapp+ op]ations call = ! use ( special iron-work+ tools4 ,s(t iron %\ld be us$1 & if a piece ( ca/-iron c be procur$ = ! lugs or magnet ends x w give bett] s]vice ?an wr\ght-iron4 ,f ?ree-qu>t]-in* r\nd iron cut two cores1 ea* ?ree in*es & a half long1 & ?read !m at bo? ends1 z %[n at ,b ,b 9 ,fig4 #ag4 ,f b&-iron five-eigh?s ( an in* ?ick & "o in* & a half wide cut a yoke 7,a71 & bore ! indicat$ holes two in*es & ?ree-qu>t]s ap>t1 c5tre to c5tre4 ,^! %\ld be ?read$ s t ! cores 7,b ,b7 w screw into !m4 ,f a b> ( iron cut (f two blocks "o in* & a half by "o in* & a half by two in*es = ! lugs4 ,n[1 ) a hack-saw & a half-r\nd file1 cut out "o side ( ea* lug1 z %[n at ,c4 ,^! lugs are to be bor$ & ?read$ at "o end1 s t !y c be screw$ on ! l[] ends ( ! cores 7,c ,c74 ,= a l>g] dynamo ! yoke %\ld be made six in*es long1 "o in* ?ick1 & two in*es & a half wide4 ,! cores %\ld be ( "o-in* iron pipe4 ,^! w be holl[1 z %[n at ,b ,b 9 ,fig4 #ah4 ,= ! ends ca/-iron blocks mu/ be made or ca/ f a patt]n two in*es & ?ree-qu>t]s squ>e & f\r in*es high1 z %[n at ,c4 ,! yoke 7,a7 & ! lugs 7,c7 are bor$ & ?read$ to receive ! "o-in* pipe1 & :5 set up ?is w con/itute an iron field-magnet six in*es wide1 two in*es ?ick1 & n9e in*es high4 ,?is1 if prop]ly w\nd1 %\ld develop a qu>t] ( a horse-p[]4 ,illu/ration3 ,,fig4 #ag ,illu/ration3 ,,fig4 #ah ,illu/ration3 ,,fig4 #ai ,illu/ration3 ,,fig4 #bj ,illu/ration3 ,,fig4 #ba ,! p>ts %[n 9 ,fig4 #ag1 :5 screw$ toge!r1 w give y a field-magnet two by "o & a half by five & ?ree-qu>t] in*es high1 & w appe> z %[n 9 ,fig4 #ai1 ,a be+ ! yoke at ! top1 ,b ,b ! cores1 ,c ,c ! lugs1 & ,d a /rip ( brass screw$ fa/ across ! back ( ! lugs 7,c ,c71 & 9 :i* a hole is bor$ to act z a be>+ = "o end ( ! armature %aft4 ,betwe5 ! lugs & ! /rip 7,d7 fibre wa%]s ?ree-eigh?s ( an in* 9 ?ickness are plac$ to keep ! /rip away f ! lugs4 ,a hole is bor$ directly ?r\gh ! middle ( ea* lug1 f front to re>1 & x is ?read$ at ea* end s t a ma*9e-screw w fit 9 x4 ,! brass /rip 7,d7 is five-eigh?s ( an in* wide1 ?ree-sixte5?s ( an in* ?ick1 & f\r in*es long4 ,copp] or ,g]man-silv] may be us$ 9 place ( brass1 b iron or /eel mu/ n be employ$1 s9ce ^! metals are susceptible to magnetism4 ,two holes %\ld be made 9 ! bottom ( ea* lug1 & ?read$1 s t ma*9e-screws may be pass$ ?r\gh a wood5 base & into !m 9 ord] to hold ! dynamo on ! base4 ,figure #bj is an end view ( ! field-magnets %[+ ! yoke at ,a1 ! core at ,b1 ! lug at ,c1 & ! be>+ & b9d+-/rip ( yell[ metal at ,d4 ,two blocks ( h>d-wood1 an in* squ>e & "o in* & a half long1 are cut & provid$ ) holes1 s t !y c be fa/5$ to ! lugs ,c ,c ) long1 slim ma*9e-screws1 z %[n at ,e ,e 9 ,fig4 #ba4 ,?is is a view look+ d[n on ! magnets1 blocks1 & /raps4 ,^! blocks are to support ! bru%es & t]m9als1 & %\ld be l9k$ across ! face ) a brass /rap ,g1 s t ! o!r end ( ! armature %aft may be support$4 ,c>e mu/ be tak51 :5 sett+ /raps ,d & ,g1 to h !m l9e4 ,! holes1 too1 mu/ be c5tr$1 s9ce ! armature mu/ revolve accurately )9 ! field-lugs 7,c ,c7 )\t t\*+ !m1 & !re is b "o-sixte5? ( an in* space betwe5 !m4 ,f h>d-wood half an in* 9 ?ickness cut a base1 six by sev5 in*es1 & two /rips an in* wide & five in*es long4 ,) glue & screws driv5 up f ! und]side ( ! /rips fa/5 !m to ! base1 z %[n at ,fig4 #bb4 ,!n make ! field-magnets fa/ to ! base ) long ma*9e-screws1 us+ wa%]s "u ! heads at ! und]side ( ! base-bo>d4 ,! m\nt+ %\ld !n appe> z %[n 9 ,fig4 #bh4 ,illu/ration3 ,,fig4 #bh ,f /eel1 half an in* 9 diamet]1 cut a %aft five in*es long4 ,h x turn$ d[n small] at "o end = ?ree-eigh?s ( an in*1 & at ! o!r end = a di/ance ( "o in* & a half1 z %[n at ,fig4 #bc4 ,?is is = ! armature1 & x %\ld fit betwe5 ,d & ,g 9 ,fig4 #ba1 & %\ld revolve easily 9 ! holes cut to receive x 9 bo? /raps1 ) n m ?an "o-eigh? ( an in* play =w>d or backw>d4 ,! long1 project+ end %\ld be at ! re>1 & %\ld ext5d beyond /rip ,d = ?ree-qu>t]s ( an in*1 s t ! driv+-pulley c be made fa/ to x4 ,! armature is made up ( segm5ts or lam9ations ( s(t iron & insulat$ copp] wire4 ,! lam9at$ armature works mu* bett] ?an does ! solid metal r+ or lug1 & a patt]n may be made f a piece ( t9 f :i* all ! sections c be cut4 ,) a compass1 /rike a two-in* circle on a cle> piece ( t92 !n m>k x (f1 z %[n at ,fig4 #bd1 & cut x out ) %e>s4 ,! hole at ! c5tre ( ! patt]n ne$ n be bor$1 b a small p9hole %\ld be made s t a c5tre-pun* c be us$ to indicate ! middle ( ea* plate = subsequ5t p]=ation4 ,ord9>y s(t b& iron may be employ$ = ?is purpose1 & ! sections %\ld n be m ?an "o-sixte5? ( an in* 9 ?ickness4 ,x w take "s "t to cut out ! requir$ numb] ( pieces = ?is small armature4 ,:5 !y are all ready !y %\ld be slipp$ ov] ! %aft1 & if !y h be5 prop]ly mat*$ & cut1 !y %\ld appe> z a solid body1 "o in* & a half long4 ,arrange ^! lam9ations on ! armature %aft s t :5 ! %aft is 9 position ! mass ( iron w be )9 ! lugs ( ! field-magnets4 ,! holes ?r\gh ! iron plate %\ld be s snug z to call = "s driv+ to put !m 9 place4 ,ea* disk ( iron %\ld be giv5 a coat ( %ellac to insulate x1 & betwe5 ea* piece !re %\ld be a ?9 c>dbo>d or /\t pap] sep>ator to keep ! disks ap>t4 ,^! pap] wa%]s %\ld be dipp$ 9 hot p>aff9e1 or ?ick %ellac may be us$ to obta9 a good /ick+ effect & s solidify ! lam9ations into a compact mass4 ,:5 ?is op]ation is complet$ ! armature core %\ld appe> z %[n 9 ,fig4 #be4 ,illu/ration3 ,,fig4 #bb ,illu/ration3 ,,fig4 #bc ,illu/ration3 ,,fig4 #bd ,illu/ration3 ,,fig4 #be ,illu/ration3 ,,fig4 #bf ,illu/ration3 ,,fig4 #bg ,illu/ration3 ,,fig4 #bi ,illu/ration3 ,,fig4 #cj ,f maple1 or o!r h>d-wood ) a close gra91 make a cyl9d] ?ree-qu>t]s ( an in* long & "o in* 9 diamet] to fit ! %aft4 ,ov] ?is drive a piece ( copp] or brass tub+1 & at f\r equal di/ances1 ne> ! re> or inn] edge1 make holes & drive small1 r\nd-head$ screws into ! wood4 ,!n1 ) a hack-saw1 cut ! tube into f\r equal p>ts betwe5 ! screws4 ,?is is ! commutator4 ,9 ord] to hold ! qu>t] circul> plates fa/ to ! cyl9d]1 remove "o screw at a "t1 & place ?ick %ellac on ! cyl9d]4 ,!n press ! plate firmly into place & reset ! screw4 ,repeat ?is ) ! o!r ?ree1 & ! armature w be ready = ! w9d+4 ,! voltage & amp]age ( a dynamo is reckon$ by its w9d+s1 ! size ( wire1 ! numb] ( turns1 & ! direction4 ,?is is a matt] ( figur+1 & ne$ n n[ conc]n ! "y electrician1 s9ce x is a te*nical & !oretical subject t may be /udi$ lat] on 9 m advanc$ text-books4 ,= ?is dynamo use ,no4 #bb cotton-insulat$ copp] wire = ! armature1 & ,no4 #af d\ble cotton-insulat$ copp] wire = ! field4 ,! armature1 :5 prop]ly w\nd & ready = assembl+ ) ! bru%es & wir+1 w appe> z %[n 9 ,fig4 #bf4 ,a small driv+-:eel two in*es 9 diamet] & half an in* ?ick mu/ n[ be turn$ f brass & provid$ ) a ,v-%ap$ groove on its face4 ,! hub1 at "o side1 is fitt$ ) a set-screw1 s t x c be b\nd tightly on ! %aft4 ,?is pulley is made fa/ to ! %aft at ! re> ( ! dynamo1 & on ! opposite end to :]e ! commutator hub is atta*$4 ,a diagram ( ! wir+ is %[n 9 ,fig4 #bi1 & 9 ,fig4 #cj ! mode ( atta*+ ! ends ( ! coil wires to ! commutators is indicat$4 ,two complete coils ( wire mu/ be made ab\t ea* *annel ( ! armature1 z illu/rat$ on ! drum ( ,fig4 #cj4 ,^! are sep>at$ by a /rip ( c>dbo>d dipp$ 9 p>aff9e & plac$ at ! c5tre ( a *annel :ile ! w9d+ is go+ on4 ,9 "s armatures ! coils are laid "o ov] ! o!r2 b ) ?is con/ruction1 & 9 ! case ( a %ort-circuit1 a brok5 wire1 or a burn-out1 x is impossible to rea* ! "u coil )\t remov+ ! good "o4 ,beg9 by atta*+ "o end ( ! f9e insulat$ wire to commutator ,no4 #a2 !n half fill ! *annel1 w9d+ ! wire ab\t ! armature1 z indicat$ 9 ,fig4 #cj4 ,:5 ! requir$ numb] ( turns has be5 made1 c>ry ! end ar\nd ! screw 9 commutator ,no4 #b1 b>+ ! wire to insure p]fect contact :5 caught "u ! screw-head4 ,f ,no4 #b c>ry ! wire ar\nd ?r\gh ! *annel at "r angles to ! fir/ "o1 & aft] half fill+ x br+ ! end out to commutator ,no4 #c4 ,c>ry ! wire 9 aga9 & fill up ! o!r half ( ! fir/ *annel1 & br+ ! end out to commutator ,no4 #d4 ,fill up ! rema9+ half ( ! second *annel2 !n atta* ! f9al end to commutator ,no4 #a1 & ! armature w9d+ w be complete )\t hav+ once brok5 ! /r& ( wire4 ,to keep ! coils ( wire 9 place1 & to prev5t !m f fly+ out1 "u ! c5trifugal =ce ( high spe$1 x w\ld be well to b9d ! middle ( ! armature ) wires or adhesive tape4 ,aft] driv+ d[n ! small screws ov] ! lead+-9 & lead+-out wires ! armature w be ready to m\nt 9 ! be>+s4 ,z ! blocks t support ! bru%es & b9d+-po/s p>tly close ! op5+ to ! cavity at ! front1 ! armature w h to be ins]t$ f ! back into ! /rip 7,g7 9 ,fig4 #ba4 ,!n ! back /rip 7,d7 is screw$ 9 place4 ,! armature1 :5 prop]ly m\nt$1 %\ld revolve freely & easily )9 ! field-lugs )\t friction1 & ! lugs mu/ by no means t\* ! armature4 ,f ?9 spr+-copp] bru%es may be cut & m\nt$ on ! block "u ! b9d+-po/s1 s t "o w re/ on top ( ! commutators :ile ! o!r presses up aga9/ ! und]side4 ,! wir+ is !n to be plac$ on ! field-magnets4 ,?is is c>ri$ out z describ$ = ! electric magnets on pages #ed-eh ( *apt] iv41 ea* core receiv+ five or sev5 lay]s1 or z mu* z x w hold )\t ov]lapp+ ! lug or yoke4 ,! ends ( ! wires are connect$ z %[n at ,fig4 #ad or ,fig4 #ae1 ! ends be+ c>ri$ d[n ?r\gh ! base & up aga9 9 ! "r location to meet ! foot ( a b9d+-po/4 ,! complete dynamo w appe> z %[n 9 ,fig4 #bh4 ,be=e ! dynamo is />t$ = ! fir/ "t x w\ld be well to run a /rong curr5t ?r\gh ! field coils4 ,! residual magnetism reta9$ by ! cores & iron p>ts w !n be ready = ! next impulse :5 ! dynamo is />t$ aga94 ,l>g] dynamos may be made ( ?is type4 ,) an armature1 ! core ( :i* is f\r in*es 9 diamet] & six in*es long1 hav+ eight in/ead ( f\r *annels1 & plac$ )9 a field ( proportionate size1 ! dynamo w develop "o horse-p[]4 ,a ,split-r+ ,dynamo ,ano!r type ( dynamo is %[n 9 ,fig4 #ca4 ,?is is compos$ ( a wr\ght or ca/ iron split-r+ w\nd = ! field1 an armature made up ( lam9ations1 & ! necess>y bru%es1 po/s1 commutators1 & wire4 ,illu/ration3 ,,fig4 #ca ,h a blacksmi? %ape an op5 r+ ( iron1 9 ! =m ( a ,c1 ?ree-eigh?s ( an in* ?ick & f\r in*es wide4 ,! op5+ %\ld be ?ree in*es wide1 z %[n 9 ,fig4 #cb4 ,?is r+ %\ld measure five in*es on its outside diamet]1 & ! ends are to be bor$ & ?read$ to receive ma*9e-screws4 ,two lugs are to be made f wr\ght-iron to fit on ^! ends4 ,^! %\ld be f\r in*es long1 an in* & a half high1 & ?ree-qu>t]s ( an in* ?ick at top & bottom4 ,!y %\ld be holl[$ out at ! middle1 s t an armature two in*es 9 diamet] w h "o-eigh? ( an in* play all ar\nd :5 arrang$ to revolve )9 !m4 ,holes are made ?r\gh ! lugs to receive ma*9e-screws1 :i* are driv5 into ! holes 9 ! ends ( ! iron 7,c74 ,wr\ght-iron ,l pieces are made "o in* & a half high & an in* across ! bottom1 & ) ma*9e-screws !y are made fa/ to ! backs ( ! lugs to act z feet on :i* ! field-magnet may re/1 z %[n 9 ,fig4 #cc4 ,across ! back ( ! lugs1 & set away f !m by fibre wa%]s1 a /rap ( brass is made fa/4 ,?is measures ?ree-qu>t]s ( an in* wide & a qu>t] ( an in* ?ick1 & at ! middle ( x a ?ree-eigh?-in* hole is bor$ to receive ! re> end ( ! armature %aft4 ,?is is %[n 9 ,fig4 #cd1 :i* is a front view ( ! field1 or ,c1 iron1 ! lugs 7,l ,l7 & feet 7,f ,f71 ! armature be>+ 7,s71 & ! base 7,b71 ( ?ree-qu>t]-in* h>d-wood4 ,! field-magnet is bolt$ to ! base ) lag-screws1 s t x w be held securely 9 place4 ,! lam9ations = ! armature core are two in*es 9 diamet]1 & are cut f s(t iron "o-sixte5? ( an in* ?ick4 ,!y h eight *annels1 z %[n 9 ,fig4 #ce1 & ! tub+ on ! commutator hub is divid$ into f\r p>ts s t ! t]m9als f ea* coil c be br\ght to a commutator1 z describ$ = ,fig4 #cj4 ,9 ! eight-*annel armature1 h[ev]1 !re is b "o coil ( wire 9 ea* *annel4 ,illu/ration3 ,,fig4 #cb ,,fig4 #cc ,,fig4 #cd ,,fig4 #ce ,,fig4 #cf ,,fig4 #cg ,,fig4 #ch ,,details ,,( ,,split-,,r+ ,,dynamo ,9 ,fig4 #cf a plan ( ! armature is %[n1 ,s repres5t+ ! %aft1 ,b ,b ! be>+s1 ,l ! lam9ations1 ,c ! commutators & hub1 ,p ! driv+-pulley1 & ,n ,n ! nuts t hold ! lam9ations toge!r & lock !m to ! %aft4 ,! %aft is half an in* 9 diamet]1 ! lam9ations f\r in*es ?ick1 & ! commutator b>rel "o in* 9 diamet] & ?ree-qu>t]s ( an in* long4 ,! %aft is turn$ d[n f ! middle to :]e ,p & ,c are atta*$2 !n at ! front end x is made small]1 :]e x passes ?r\gh ! front be>+4 ,) ! detail$ description already giv5 = ! con/ruction ( ! small dynamo1 x %\ld be an easy matt] to c>ry out ! "w on ?is "o1 & a qu>t] horse-p[] g5]ator %\ld be ! result4 ,! field-magnet is w\nd ) five or sev5 lay]s ( ,no4 #af d\ble cotton-insulat$ wire1 & ! armature ) ,no4 #bb silk or cotton-cov]$ wire4 ,! connections may be made = ei!r ! s]ies or ! %unt w9d+s %[n 9 ,figs4 #ad & #ae4 ,ano!r type ( field is %[n 9 ,fig4 #cg1 :]e two plates ( iron are screw$ to "o core1 & ! lugs are1 9 turn1 made fa/ to ! inn] sides ( ! plates )9 :i* ! armature revolves4 ,! 8,man*e/]0 type is %[n 9 ,fig4 #ch1 :]e two cores1 con/ruct$ by a top & bottom yoke1 are excit$ by ! coils1 & ! lugs are arrang$ betwe5 ! cores1 s t ! armature revolves )9 !m4 ,a ,small ,motor ,! %apes1 types1 p[]s1 & =ms ( motors are z v>i$ & diff]5t z ^? ( dynamos1 ea* inv5tor design+ a diff]5t type & claim+ sup]iority4 ,! "o common pr9ciple1 h[ev]1 is ! same--t ( an armature revolv+ )9 a field1 & l9es ( =ce cutt+ l9es ( =ce4 ,a motor is ! rev]se ( a dynamo4 ,in/ead ( g5]at+ curr5t to develop p[] or light1 a curr5t mu/ be run ?r\gh a motor to obta9 p[]4 ,motors are divid$ into two classes3 ! ,d ,c1 or direct curr5t1 & ! ,a ,c1 or alt]nat+ curr5t4 ,= ! amateur ! direct-curr5t motor w meet e requirem5t1 & s9ce ! batt]y1 or dynamo curr5t1 t may be available to run a motor1 is 9 all probability a direct "o1 x w be necess>y to con/ruct a motor t is adapt$ to ?is s\rce ( p[] & = ! pres5t avoid ! complications ( ! alt]nat+ curr5t bo? 9 g5]ation & 9 use4 ,! direct-curr5t motor is an electrical ma*9e driv5 by direct curr5t1 ! latt] be+ g5]at$ 9 any desir$ way4 ,?is curr5t is =c$ ?r\gh ! ma*9e by electro-motive =ce1 or voltage2 ! high] ! pressure1 or voltage1 ! m effici5t ! ma*9e4 ,be c>eful le/ too mu* curr5t 7amp]age7 is all[$ to fl[1 = ! heat develop$ !reby w burn out ! wir+4 ,motors are s con/ruct$ t :5 a curr5t is pass$ ?r\gh ! field & armature coils ! armature is rotat$4 ,! spe$ ( ! armature is regulat$ by ! am\nt ( amp]age & voltage t passes ?r\gh ! s]ies ( magnets1 & ?is rotat+ p[] is call$ ! torque4 ,torque is a twi/+ or turn+ =ce1 & :5 a pulley is made fa/ to ! armature %aft1 & belt$ to connect ) ma*9]y1 ?is torque1 or =ce1 is employ$ = "w4 ,! spe$ ( an armature :5 at full "w is usually f twelve hundr$ to two ?\s& revolutions a m9ute4 ,z few ma*9es are design$ to "w at t velocity1 a sy/em ( spe$+ d[n ) back ge>s1 or c\nt]-%afts & pulleys1 is employ$4 ,! motor itself _c be sl[$ d[n )\t los+ p[]4 ,! effici5cy ( motors is due to ! c5trifugal motion ( ! mass ( iron & wire 9 ! armature & ! mom5tum x develops :5 spurr$ on by ! magnetism ( ! field-magnets act+ ^u c]ta9 electrifi$ sections ( ! armature4 ,! armature ( a work+ motor is usually ( su* high resi/ance t ! curr5t employ$ to run x w\ld heat & burn out ! wires if ! full =ce ( ! curr5t 0 p]mitt$ to fl[ ?r\gh x = any l5g? ( "t4 ,z ! armature rotates x has c\nt] electro-motive =ce impress$ ^u x4 ,?is acts l resi/ance1 & r$uces ! curr5t pass+ ?r\gh4 ,! high] ! spe$ ! less curr5t x takes1 s t aft] a motor has atta9$ its highe/1 or normal spe$1 x is us+ less ?an half ! curr5t requir$ to />t x4 ,r$uction ( curr5t 9 ! armature r$uces torque1 s t ! turn+ =ce ( ! armature is r$uc$ z its spe$ ( rotation increases4 ,on ! o!r h&1 ! mom5tum1 or 8?r[10 produces p[] at high spe$1 toge!r ) an actual sav+ ( curr5t4 ,an armature revolv+ at sixte5 hundr$ revolutions1 & giv+ half a horse-p[] on a curr5t ( five amp]es1 is m economical ?an "o mak+ ?ree to five hundr$ revolutions1 & giv+ half a horse-p[] on a curr5t ( fifte5 to tw5ty amp]es4 ,?us1 a sl[ly turn+ armature takes m curr5t & ex]ts high] torque ?an a rapidly rotat+ "o4 ,to protect ! f9e wire on ! armature f burn+1 9 high-voltage ma*9es a />t+-box1 or rheo/at1 is employ$4 ,! motor beg9s work+ on a r$uc$ curr5t1 & z x picks up spe$ m curr5t is let 91 & s on until ! full =ce ( ! curr5t is fl[+ ?r\gh ! motor4 ,x is !n turn+ fa/ en\gh to protect itself ?r\gh ! c\nt] electro-motive =ce4 ,?is c be und]/ood bett] aft] "s practical exp]i5ce has be5 _h 9 ! con/ruction & runn+ ( motors4 ,( ! v>i\s =ms ( motors b ?ree w be illu/rat$ & describ$2 b ! boy ) ideas c readily design & con/ruct o!r types z he comes to ne$ !m4 ,! ,flat-b$ ,motor ,! simple/ ( all motors is ! flat-b$ type1 illu/rat$ 9 ,fig4 #ci4 ,?is is compos$ ( a magnet on a %aft revolv+ be=e a fix$ magnet atta*$ to ! upright bo>d ( ! base4 ,:]e space is no object1 ?is motor w develop consid]able p[] f a numb] ( dry-cells or a /orage-batt]y4 ,n[1 9 ! section relat+ to dynamos1 f\r diff]5t sy/ems ( wir+ 7 %[n4 ,9 motors ( ! direct-curr5t type b "o sy/em w be describ$--t ( ! s]ies-w9d+1 illu/rat$ 9 ,fig4 #dj4 ,! curr5t1 ent]+ at ,a1 passes to ! bru% 7,b71 !nce ?r\gh ! commutator 7,c7 & ! armature coils4 ,x runs on ?r\gh ! bru% 7,b ,b71 ! field-coils 7,f71 & out at ,d4 ,?is is ! same c\rse ! curr5t takes 9 ! s]ies-w\nd dynamo illu/rat$ 9 ,fig4 #ad1 page #bda1 & ) su* a dynamo curr5t c\ld be g5]at$ to run any s]ies-w\nd1 direct-curr5t motor4 ,illu/ration3 ,,fig4 #ci ,,fig4 #dj ,,fig4 #da ,,fig4 #db ,,fig4 #dc ,a ,,flat-,,b$ ,,motor ,,& ,,p>ts ,f h>d-wood half an in* ?ick cut a base-piece six in*es & a half long by ?ree in*es & a half wide4 ,arrange ?is base on cross-/rips ?ree-qu>t]s ( an in* wide & half an in* ?ick1 mak+ ! union ) glue & screws driv5 up f ! und]side4 ,to "o end ( ?is base atta* an upright or back two in*es & ?ree-qu>t]s high1 & all[ ! l[] edge to ext5d d[n to ! bottom ( ! cross-/rip1 z %[n at ! left ( ,fig4 #ci4 ,make ?is fa/ to ! end ( ! base & side ( ! cross-/rip ) glue & screws2 !n give ! wood a coat ( /a9 & %ellac to prop]ly f9i% x4 ,n[ h a blacksmi? make two ,u pieces ( s(t iron = ! field & armature cores1 z %[n 9 ,fig4 #da4 ,^! are ( qu>t]-in* iron "o in* & a half 9 wid?4 ,!y are "o in* & ?ree-qu>t]s across & ! same 9 l5g?4 ,"o ( !m %\ld h a half-in* hole bor$ 9 ! end 7at ! middle71 & above & bel[ x small] holes = r\nd-head$ screws to pass ?r\gh4 ,by means ( ^! screws ! ,u is held to ! wood5 back4 ,! o!r ,u is to h a ?ree-eigh?-in* hole bor$ 9 x s t x w fit on ! armature %aft4 ,w9d ! ,u irons ) six lay]s ( ,no4 #bj cotton-insulat$ wire1 hav+ fir/ cov]$ ! b>e iron ) sev]al wraps ( pap]4 ,use ?ick %ellac freely aft] ea* lay] is on1 s t ! turns ( wire w be well insulat$ & b\nd to ea* o!r4 ,foll[ ! wir+ diagram %[n 9 ,fig4 #dj :5 w9d+ ^! cores1 & :5 ! field is ready1 make x fa/ to ! back ) ?ree-qu>t]-in* r\nd-head$ brass screws4 ,directly 9 ! middle ( ! hole ?r\gh ! field iron bore a qu>t]-in* hole = ! armature %aft to pass ?r\gh2 !n make an ,l piece1 ( brass1 two in*es high1 ?ree-qu>t]s ( an in* wide1 & ) ! foot an in* long1 z %[n at ,fig4 #db4 ,two holes are made 9 ! foot ?r\gh :i* screws w pass into ! base1 & ne> ! top a qu>t]-in* hole is to be bor$1 ! c5tre ( :i* is to l9e ) t ?r\gh ! back1 at ! middle ( ! field core4 ,! %aft is made f /eel ?ree-eigh?s ( an in* 9 diamet] & six in*es & a half long4 ,"o in* f "o end ! %aft %\ld be turn$ d[n to a qu>t] ( an in* 9 diamet]1 & "o in* & a qu>t] f ! o!r end x mu/ be r$uc$ to a simil> size4 ,! %ort end m\nts 9 ! back & ! long "o receives ! pulley1 aft] ! latt] passes ?r\gh ! ,l be>+4 ,a piece ( ?ree-eigh?-in* brass tub+ an in* long is slipp$ ov] ! %aft two in*es f ! pulley end & secur$ ) a flu% set-screw4 ,?is tub+ is !n ?read$ & provid$ ) two nuts1 "o at ei!r end1 s t :5 ! armature ,u is slipp$ on ! coll> ! nuts c be tight5$ & made to hold ! magnet securely on ! %aft4 ,?is %aft is cle>ly %[n 9 ! sectional draw+s ,fig4 #dc4 ,at ! left side ! %aft 7,s7 passes into ! wood back ?r\gh ! qu>t]-in* hole4 ,at ! outside a brass plate ) a qu>t]-in* hole is screw$ fa/ & acts z a be>+4 ,! %aft does n t\* ! field-magnet 7,f ,m71 because ! hole is l>ge en\gh = ! qu>t]-in* %aft to cle> x4 ,a fibre wa%] 7,f ,w7 is plac$ on ! %aft be=e x is slipp$ ?r\gh ! back4 ,?is prev5ts ! %aft f play+ too mu*1 & dead5s any s\nd ( 8jump+0 :ile rotat+4 ,at ! middle ! %aft 7,s7 passes ?r\gh ! brass coll> on :i* ! ?reads are cut4 ,a ,m repres5ts ! armature magnet1 & ,w ,w ! wa%]s & nuts employ$ to b9d x 9 place4 ,at ! "r1 ,s aga9 repres5ts ! %aft1 ,b ! be>+1 ,c ! commutator hub1 & ,p ! pulley1 :ile ,r is ! small block "u ! hub to :i* ! bru%es & b9d+-po/s are atta*$4 ,f ! descriptions already giv5 ( dynamos1 & ) ^! figure draw+s z a guide1 x %\ld be an easy matt] to assemble ?is motor4 ,! ends ( ! field & armature magnets %\ld be sep>at$ an eigh? ( an in*4 ,! hub = ! commutators is ?ree-qu>t]s ( an in* long & ?ree-qu>t]s ( an in* 9 diamet]4 ,! commutators are made z describ$ = ! uni-direction curr5t ma*9e1 c>e be+ tak5 to keep ! hold+ screws f t\*+ ! %aft4 ,a ?ree-qu>t]-in* cube ( wood is m\nt$ on ! base1 "u ! commutator hub1 & to ?is ! bru%es & b9d+-po/s are made fa/1 z %[n 9 ,fig4 #ci4 ,unless ! armature happ5s to be 9 a c]ta9 position ?is motor is n self-/>t+1 b a twi/ on ! pulley1 z ! curr5t is turn$ on1 w give x ! necess>y />t4 ,its spe$ w !n dep5d on ! am\nt ( curr5t =c$ ?r\gh ! coils4 ,ano!r ,simple ,motor ,ano!r type ( motor is %[n 9 ,fig4 #dd1 :]e "o field-w9d+ magnetizes bo? ! core & ! lugs4 ,! frame ( ?is motor is made up ( two plates ( s(t iron a qu>t] ( an in* ?ick1 six in*es long1 & two in*es & a half wide4 ,ea* plate is b5t at "o end s z to =m a foot ?ree-qu>t]s ( an in* long1 & a half-in* hole is drill$ "o in* & a qu>t] up f ! bottom1 at ! middle ( ea* plate4 ,?r\gh ?is hole pass ! ma*9e-screws :i* hold ! iron core 9 place betwe5 ! side-plates4 ,! core is made ( ?ree-qu>t]-in* r\nd iron two in*es & ?ree-qu>t]s long1 & drill$ & ?read$ at ea* end to receive ! b9d+ ma*9e-screws4 ,two lugs are cut f iron1 & holl[$ at "o side s t an armature two in*es 9 diamet] w rotate )9 !m :5 made fa/ to ! side-plates4 ,! lugs are two in*es & a half long1 an in* wide1 & two in*es & a half high4 ,f iron five-eigh?s ( an in* wide & "o-eigh? ( an in* ?ick make two side-/rips ) ,l ends4 ,^! are f\r in*es long1 & are provid$ ) two holes s t ! ma*9e-screws :i* hold ! lugs to ! inside plates w also hold ^! /rips 9 place1 at ! outside1 z %[n 9 ,fig4 #de4 ,at ! re> ^! /rips ext5d half an in* beyond ! frame4 ,across ! back a brass /rip ( ! same size z ! iron /rips is arrang$4 ,x is held at ! ends by screws1 or small bolts1 made fa/ to ! ,l ends ( ! side-/rips4 ,directly 9 ! middle ( ! back-/rip a hole is made = ! armature %aft1 & beyond x ! pulley is key$ or screw$ fa/ to ! %aft4 ,at ! front a simil> /rip is made & atta*$4 ,?is latt] has a small hole 9 ! middle ( x to s]ve z a be>+ = ! =w>d end ( ! %aft4 ,across ! top ( ! motor a brass /rip or b& is made fa/ ) ma*9e-screws2 & at ! angles =m$ by ! front ends ( ! side-/rips & ! front cross-/rips h>d-wood blocks are atta*$4 ,to ^! ! bru%es & b9d+-po/s are made fa/1 s t "o bru% at ! top ( ! left-h& block re/s on ! top ( ! commutator4 ,! "o at ! und]side ( ! opposite block mu/ re/ on ! und]side ( ! commutator4 ,illu/ration3 ,,fig4 #dd ,illu/ration3 ,,fig4 #de ,! armature core is made up ( lam9ations z describ$ = ! dynamo armatures4 ,9 a really effici5t motor ! armature %\ld h eight or m *annels4 ,! o!r p>ts ( ! motor may be assembl$ & wir$ z describ$ on ! prec$+ pages4 ,! armature %\ld be w\nd ) ,no4 #bj or #bb insulat$ copp] wire1 & ! field ) ,no4 #af or #ah4 ,= high voltage1 h[ev]1 ! armature %\ld be w\nd ) f9] wire & a rheo/at us$ to />t x4 ,a ,?ird ,type ( ,motor ,! ?ird type is b a duplicate ( ! s]ies-w\nd dynamo1 ! g5]al plan ( :i* is %[n 9 ,fig4 #dj4 ,?is motor c be made any size1 b z its dim5sions are increas$ ! weight ( ! field-magnets & armature mu/ be proportionately enl>g$4 ,= an effici5t & p[]ful motor1 ! field %\ld /& t5 in*es high & six in*es broad4 ,! iron cores are five in*es long & "o in* & a half 9 diamet]4 ,^! %\ld be made by a blacksmi? & bolt$ toge!r4 ,! armature is ?ree in*es 9 diamet] & f\r in*es long1 & %\ld develop two-?irds ( a horse-p[] :5 suffici5t curr5t is runn+ ?r\gh ! coils to drive x at sixte5 hundr$ revolutions4 ,! wir+ is c>ri$ out z %[n 9 ,fig4 #dj1 & ! armature hung & w\nd z sugge/$ = ! dynamo %[n 9 ,fig4 #bh1 page #bdf4 ,*apt] ,,xi ,,galvanism ,,& ,,electro-,,plat+ ,simple ,electro-plat+ ,to ! av]age boy exp]im5t]1 electro-plat+ is "o ( ! mo/ fasc9at+ ( ! uses to :i* electricity may be put4 ,9 sci5tific language ! process is kn[n z electrolysis1 & involves ! sep>ation ( a *emical comp\nd into its con/itu5t p>ts or elem5ts by ! action ( an electric curr5t & ! prop] app>atus4 ,electrolysis _c take place1 h[ev]1 unless ! liquid 9 ! tank1 commonly call$ ! electrolyte 7no relation to electric light71 is a conductor4 ,wat]1 or wat] ) mixtures ( *emicals1 su* z sulphate ( copp]1 sulphate ( z9c1 *loride ( nickel1 cyanide & nitrate ( silv]1 or uranium & o!r metallic salts1 are good conductors4 ,oil is a non-conductor1 & a curr5t w n pass ?r\gh x1 no matt] :at ! pressure may be4 ,! simple/ electro-plat+ outfit1 & ! "o t a boy %\ld />t )1 is ! sulphate ( copp] ba?1 su* z is commonly employ$ by mak]s ( electrotypes1 & :i* is 9 ext5sive use by ref9]s ( copp] = high-grade electrical use4 ,m ?an half ( ! total output ( copp] 9 ! _w is us$ = electrical "w--conductors1 swit*es1 & all sorts ( p>ts--& s9ce any impurity 9 ! copp] int]f]es ) its conduct+ p[]s1 x is mo/ important t x %\ld be free f any traces ( c>bon or ars5ic4 ,! electrolytic ref9+ ( copp] is n[ a v important process 9 connection ) electric "w1 & ab\t half a million tons ( copp] are treat$ annually to free x f all impurities4 ,moreov]1 ! gold1 silv]1 & o!r valuable metals :i* may be f\nd 9 copp]-ore are ?us recov]$4 ,! electro-plat+1 electrotyp+1 & ref9+ op]ations are "o & ! same ?+2 b 9 ! fir/ in/ance ! object to be plat$ is left 9 ! solution only a %ort "t or until a blu% ( copp] has be5 appli$4 ,9 ! second process ! wax mold is left 9 long en\gh = a ?9 %ell ( copp] to be deposit$2 & 9 ! ?ird1 ! ka?odes are imm]s$ until !y are heavily coat$ ) copp]4 ,to c>ry on any ( ^! op]ations x w be necess>y to h a small tank or glass j> to hold ! plat+-ba? or electrolyte4 ,pref]ably x %\ld be ( a squ>e or oblong %ape4 ,b a s]viceable tank may be con/ruct$ f :ite-wood1 p9e1 or cypress1 if prop] c>e is tak5 9 mak+ & wat]-pro(+ 7,fig4 #a74 ,= exp]im5tal purposes a tank eighte5 in*es long1 t5 in*es wide1 & twelve in*es deep w be q l>ge en\gh to use z a copp] ba?4 ,= silv]1 nickel1 or gold1 small] tanks %\ld be employ$1 z !y conta9 less liquid1 or electrolyte1 :i* 9 ! m valuable metals is exp5sive4 ,obta9 a cle> plank twelve in*es wide1 well season$1 & free f knots or sappy places4 ,cut two sides tw5ty in*es long & two ends eight in*es long4 ,) *isel1 saw1 & plane %ape ! ends ( ! side planks z %[n at ,fig4 #b2 or if !re is a mill at h& x w\ld be well to h ! ends cut ) a buzz-saw1 ?us insur+ t !y w be accurate & fit snugly4 ,screw-holes are bor$ ) a gimlet-bit1 & c\nt]sunk1 s t screws w pass freely ?r\gh !m & take hold 9 ! edges ( ! bo>ds4 ,screws & pl5ty ( :ite-lead1 or asphaltum v>ni%1 %\ld be us$ on ^! po9ts to make !m wat]-tight2 !n ! l[] edge ( ! frame is prep>$ = ! bottom bo>d4 ,turn ! tank bottom up1 &1 ) a fat /eel-wire nail & a hamm]1 d5t a groove at ! middle ( ! edge ( ! planks all ar\nd1 z %[n 9 ,fig4 #c4 ,x w n d to cut ?is out ) a g\ge-*isel1 because x is int5d$ t ! wood %\ld swell out aga9 if necess>y4 ,! object ( driv+ ! wood d[n is to =m a valley into :i* a l9e ( cotton /r+-wick+1 soak$ 9 asphaltum v>ni% or imb$d$ 9 :ite-lead1 may be laid4 ,?is %\ld be done 7z %[n 9 ,fig4 #d7 be=e ! bottom is screw$ on1 s t aft]w>ds 79 ! ev5t ( ! jo9t leak+7 ! wood w swell & =ce ! wick+ out1 & ?us prop]ly close ! fissure4 ,! bottom bo>d %\ld be provid$ ) holes all ar\nd ! edge1 n m ?an two in*es ap>t1 ?r\gh :i* screws c be driv5 into ! l[] edge ( ! tank4 ,treat ! wood1 bo? 9 & outside1 to sev]al successive coats ( asphaltum v>ni%1 & z a result y w h a tank resembl+ ,fig4 #a4 ,two %all[ grooves are to be cut 9 ! top ( ea* end bo>d ( ! tank1 = ! cross-b>s to fit 9 immovably4 ,^! b>s %\ld be ab\t ?ree in*es ap>t2 & ! ones hold+ ! anodes1 or flat copp] plates1 %\ld be close to "o side1 leav+ pl5ty ( room = objects ( v>i\s sizes to be prop]ly imm]s$4 ,ano!r mann] 9 :i* ! bottom ( ! tank c be atta*$ is %[n 9 ,fig4 #e1 :i* is a view ( ! tank sides turn$ bottom up4 ,a rabbet is cut f ! l[] edges ( ! sides & ends1 be=e !y are screw$ toge!r1 & a bottom is fa%ion$ ( su* %ape z to accurately fit 9 ! lap =m$ by ! rabbet4 ,?is rabbet & ! out] edge ( ! bottom plank %\ld be well sme>$ ) :ite-lead1 & all put toge!r at ! same "t1 driv+ ! screws into ! edge ( ! bottom plank1 ?r\gh ! l[] edges ( ! sides & bottom1 & also ?r\gh ! bottom bo>d into ! l[] edges ( ! sides & ends 7,fig4 #f74 ,/ill ano!r & /rong] way 9 :i* to make a tank = a l>ge ba? is to cut ! planks z %[n at ,fig4 #g4 ,! sides are !n bolt$ toge!r1 lock+ ! ends & bottom1 s t !y _c w>p or get away4 ,! bolts are ( ?ree-eigh?-in* r\nd iron-rod1 ?read$ at bo? ends & provid$ ) nuts4 ,l>ge wa%]s are plac$ aga9/ ! wood & "u ! nuts1 s t :5 ! nuts are screw$ on tightly !y w n te> ! wood1 b w be> on ! wa%]s4 ,! po9ts are all to be well sme>$ ) :ite-lead or acid-pro( cem5t 7see ,=mul7 be=e ! p>ts are put toge!r & bolt$1 s z to avoid any possibility ( leakage4 7,fig4 #h %[s ! complet$ tank47 ,illu/ration3 ,,fig4 #a ,,fig4 #b ,,fig4 #c ,,fig4 #d ,,fig4 #e ,,fig4 #f ,,fig4 #g ,,fig4 #h ,,tank ,,= ,,electro-,,plat+ ,n[ obta9 two copp] rods long en\gh to span ! tank1 ) an in* or two project+ beyond ! tank at ei!r side4 ,at "o end ( ^! atta* b9d+-po/s1 to :i* ! wires f a batt]y c be connect$1 leav+ ! opposite ends free1 z %[n at ,fig4 #i 7see page #bge74 ,anodes1 or pure s(t copp] plates1 are hung on ! positive rod1 :ile on ! negative "o ! objects to be plat$1 or ka?odes1 are susp5d$ on f9e copp] wires j heavy en\gh to prop]ly conduct ! curr5t4 ,! positive wire leads f ! c>bon1 or copp] pole1 ( ! batt]y1 :ile ! negative "o is connect$ ) ! z9c4 ,! anodes are plates ( s(t %eet or ca/ copp]1 & %\ld be z ne>ly pure z possible = electrolytic "w2 b if !y are to be re-deposit$1 to free !m f impurities1 !y may be 9 ?9 +ot =m1 j z ! copp] comes f ! m9es4 ,! g5]al pr9ciple ( electro-ref9+ ( copp] is v simple4 ,a ca/ plate ( ! crude copp] is hung f ! positive pole 9 a ba? ( sulphate ( copp]1 made by dissolv+ all ! sulphate ( copp]1 or blue/one1 t ! wat] w take up4 ,drop a few lumps on ! bottom ( ! tank to supply any defici5cy1 !n add an ounce ( sulphuric acid to ea* gallon ( liquid1 to make x m active & a bett] conductor4 ,! crude copp] plate is to be ! lead+-9 pole = ! curr5t1 :ile a ?9 %eet ( pure copp]1 no ?ick] ?an tissue-pap]1 is susp5d$ f ! opposite rod = ! lead+-out pole2 or 9 place ( ! ?9 %eet1 "s copp] wires may be susp5d$ f ! rod4 ,! electrodes--t is1 ! copp] plate & ! ?9 %eet or wires--are plac$ close toge!r1 s t ! curr5t may pass freely & n cause int]nal resi/ance 9 ! batt]y4 ,! electric curr5t1 9 its passage f ! crude copp] plate to ! pure copp] %eet or wires1 decomposes ! sulphate ( copp] solution & causes x to deposit its metallic copp] on ! %eet or wires2 & at ! same "t x takes f ! crude copp] a l portion ( metallic copp] & conv]ts x into *emical copp]4 ,! electric curr5t really takes ! copp] f ! solution & adds x to ! pure copp] %eet1 :ile ! rema9+ con/itu5ts ( ! decompos$ solution help !mselves to "s copp] f ! crude plate4 ,9 ?is way ! crude copp] dim9i%es & ! pure copp] %eet increases 9 size1 ! impurities z well z ! salts ( o!r metals be+ precipitat$ to ! bottom ( ! tank1 or m+l$ ) ! solution1 :i* mu/ be purifi$ or replac$ f "t to "t by fre% solution4 ,?is is ! process ( copp]-plat+1 & any metal object may be prop]ly cleans$ & coat$ ) copp] by susp5d+ x 9 ! ba? & runn+ ! curr5t ?r\gh x4 ,:5 ! ref9+ process is employ$1 any metal w answ] z a depository = ! copp]1 b z ! int5tion is to produce a pure copp] plate :i* c be melt$ & ca/ into +ots1 x is ( c\rse necess>y to h ! orig9al ka?ode ( ! same metal2 o!rwise an impure mixture w be ! result4 ,if1 = example1 a piece ( ca/-iron be us$ ^u :i* to deposit ! copp]1 !n ! iron w be enclos$ 9 a deposit ( pure copp]2 9 o!r words1 ! result w be a heavily copp]-plat$ piece ( iron1 & ! smelt+ process w br+ ab\t a fusion ( ! two metals4 ,x is n necess>y to h absolutely pure copp] = ! anodes :5 copp]-plat+ or electrotyp+2 b ! pur] ! copp] ! less ! solution is f\l$1 & x w n require repl5i%+ s (t54 ,an object int5d$ to receive a plat+ ( copp] ne$ n be ( metal at all2 x may be ( any mat]ial1 s long z x possesses a conduct+ surface4 ,a mold or a ca/ made ( any pla/ic mat]ial1 su* z wax or cem5t1 may h its surface made conductive by ! application ( graphite1 f9ely pulv]iz$ c>bon1 or metal du/s held on by "s m$ium n soluble 9 wat]4 ,! wax molds1 or impressions ( type & cuts1 are du/$ ) plumbago1 & !n susp5d$ 9 ! copp] solution4 ,a wire f ! negative pole is connect$ s z to come 9 contact ) ! plumbago1 & ! copp] deposit imm$iately beg9s to =m on ! face ( ! wax4 ,:5 ! film ( copp] has become heavy en\gh1 ! mold is drawn out ( ! solution1 & ! ?9 %ell ( metal remov$ f ! wax & cut ap>t1 s t ea* %ell is sep>at$ f its neighbor & fre$ f m>g9al scraps4 ,fl[]s1 leaves1 laces1 & v>i\s o!r objects c be giv5 a coat ( copp] by ?us prep>+ _! surfaces1 & "s mo/ beautiful effects may be secur$ by copp]-coat+ roses2 !n plac+ !m = a %ort "t 9 a gold ba?1 & aft]w>ds *emically treat+ ! surface plat+ s z to imitate ,roman1 ,tuscan1 or ormolu gold1 9 bright or antique f9i%4 ,co9s1 m$allions1 bas-reliefs1 m$als1 & v>i\s o!r ?+s are reproduc$ by ! electro-plat+ process1 & _! surfaces f9i%$ 9 gold1 silv]1 bronze1 or o!r effects4 ,ye>s ago ?is 0 n possible1 because ! old me?od 0 to make a fac-simile ca/ 9 metal ( ! object desir$1 & !n *ase or ref9i% ! surface4 ,?is 0 a co/ly & t$i\s task4 ,:5 ,brugnalelli1 an ,italian electrician1 electro-gild$ two silv] co9s 9 #ahje1 he laid ! f\ndation = ! mod]n process1 b x did n come into g5]al use until ab\t #ahci1 :5 electro-plat+ & ! electro-deposit+ ( metals 0 begun on a practical scale4 ,be=e ! inv5tion ( ! dynamos = g5]at+ curr5t1 batt]ies _h to be employ$1 & ?is made ! process some:at m exp5sive ?an ! pres5t me?od4 ,our boy amateurs1 h[ev]1 w h to be cont5t ) ! batt]y sy/em1 s9ce !y are n suppos$ to h access to direct-curr5t p[]1 su* z is us$ = arc or /reet light+4 ,v>i\s =ms ( batt]ies may be us$ = ?is "w1 & !y w be describ$ 9 detail4 ,= ! copp]-plat+ ba? x w be necess>y to h ! anodes ( s(t1 ca/1 or %eet1 copp] suffici5tly heavy s z n to wa/e away too quickly4 ,^! %\ld be ( ! prop] size to fit )9 ! ba?1 & ei!r "o l>ge "o or sev]al small ones may be employ$4 ,/\t copp] b&s %\ld be rivet$ to ! top ( ! plates1 by means ( :i* !y may be hung on ! b> & s susp5d$ 9 ! solution 7,fig4 #aj74 ,! contact-po9ts %\ld be kept clean & bright1 s t ! curr5t w n meet ) any resi/ance 9 pass+ f ! rod to ! plates4 ,9 ,fig4 #i a complete outfit is %[n = any plat+ process1 ! diff]5ce be+ only 9 ! solution & anodes4 ,= silv]-plat+ a silv] solution & silv] anodes are requir$1 :ile = gold ! gold solution & gold anodes w be necess>y4 ,9 ?is illu/ration1 ,a repres5ts ! tank1 ,b ! batt]y1 ,c ,c ! anodes1 ,d ,d ,d ! ka?odes1 or articles to be plat$1 ,e ! positive rod1 ,f ! negative1 & ,g1 ,h ! lead+-9 & lead+-out wires4 ,!re is (t5 a d\bt 9 a boy's m9d z to h[ ! batt]y is to be connect$ up to ! ba? & ! articles susp5d$ 9 x4 ,b !re w be no difficulty ab\t x once t ! pr9ciple ( ! process is ?or\ghly und]/ood4 ,illu/ration3 ,,fig4 #i4 ,x is well to rememb] t ! electro-plat+ ba? is j ! rev]se ( a batt]y 9 its action4 ,! process c>ri$ on 9 a batt]y is ! g5]ation ( electricity by ! action ( ! acid on ! positive metal1 accompani$ by ! =mation ( a salt on "o ( ! elem5ts2 :ile 9 ! plat+-ba? ! curr5t f an ext]nal s\rce 7! batt]y or dynamo7 breaks up ! salts 9 solution & deposits ! metal on "o ( ! elem5ts 7! ka?ode74 ,! rema9+ elem5t 9 ! solution attacks ! salts1 9 *emical lumps or granul> =m1 & dissolves !m to take ! place ( ! exhau/$ salts2 or x attacks ! metal anode f :i* ^! salts 7 orig9ally made1 & eats (f ! portion necess>y to replace ! loss caus$ by ! action ( ! curr5t 9 deposit+ ! fruits ( ?is robb]y 9 metallic =m ^u ! article to be plat$ 7! ka?ode74 ,!re %\ld be no confusion 9 ! matt] ( prop]ly connect+ ! poles if "o rememb]s t ! curr5t is fl[+ ?r\gh ! batt]y z well z ?r\gh ! wires & ! solution 9 ! tank4 ,get cle>ly 9 y\r m9d t ! curr5t orig9ates 9 ! batt]y ( z9c & c>bon or z9c & copp]4 ,! z9c is electro-positive to c>bon or copp]1 & at a high] electric level ! curr5t fl[s f ! z9c plate inside ! cell to ! c>bon or copp]2 !re=e1 ! z9c is ! positive pole4 ,n[ ! curr5t1 hav+ fl[$ ?r\gh ! batt]y f z9c to c>bon1 or ! negative plate1 is b\nd to fl[ out ( ! batt]y f ! c>bon ?r\gh ! app>atus & back aga9 to ! z9c 9 ! batt]y4 ,!re=e1 ! wire 7,g7 atta*$ to ! c>bon ( ! batt]y leads a positive or curr5t1 al?\gh ! c>bon is negative2 9 ! batt]y1 & ! wire 7,h7 lead+ out is negative1 or -1 al?\gh x returns ! curr5t to ! positive pole ( ! batt]y4 ,?is is ! simple explanation ( ! circulation ( curr5t2 b to cut x d[n /ill m1 always rememb] to atta* ! wire f ! anode rod to ! c>bon1 or copp]1 ( ! batt]y1 & ! ka?ode rod to ! z9c ( ! batt]y4 ,9 copp]-plat+ ?is is easy to det]m9e )\t any reg>d to wires1 because if ! wires are misconnect$ !re w be no deposit1 & ! ka?ode w turn a d>k color4 ,if ev]y?+ is all "r a slight rose-color$ blu% ( copp] w appe> at once on ! ka?ode4 ,too little curr5t w make ! process a long & t$i\s "o1 :ile too mu* curr5t w deposit a br[n mud on ! ka?ode1 :i* w h to be wa%$ (f or remov$ & ! article ?or\ghly cleans$ be=e a new action is all[$ to take place4 ,) a s]ies ( cells x is an easy matt] to prop]ly gov]n ! curr5t by cutt+ out "s ( ! cells or by us+ resi/ance-coils 7see *apt] vii4 on ,electrical ,resi/ance74 ,cells & batt]ies = electro-plat+ may be made or pur*as$1 & prim>y batt]ies %\ld be us$4 ,! use ( ! second>y or /orage-batt]y is n necess>y = plat+ purposes1 s9ce no great volume ( curr5t is ne$$1 & x c be g5]at$ 9 a batt]y ( cells :ile ! "w is go+ on4 ,"o ( ! be/ prim>y batt]ies is ! ,b5son cell1 %[n 9 connection ) ! plat+-ba?1 & also 9 ,fig4 #aa4 ,x consi/s ( an out] glass j> 7,g ,j71 :i* conta9s a cyl9d] ( amalgamat$ z9c 7,z 1 or positive7 cov]$ ) dilut$ sulphuric acid--"o "p acid to ?ree p>ts wat]4 ,an inn] por\s cup 7,p ,c7 conta9s conc5trat$ nitric acid1 into :i* ! c>bon 7,c -1 or negative7 is plung$4 ,! liquid 9 ! inn] cup & glass cell %\ld be at ! same level4 ,illu/ration3 ,,fig4 #aj ,,fig4 #aa ,,fig4 #ab ,,! ,,b5son ,,cell ,,prim>y ,,batt]y ,!re is no pol>iz+ 9 ?is cell1 = ! hydrog5 lib]at$ at ! z9c plate1 9 pass+ ?r\gh ! nitric acid on its way to ! c>bon-pole1 decomposes ! nitric acid & is itself oxidiz$4 ,a cell ) a glass j> six in*es 9 diamet] & eight in*es high w develop ab\t two volts ( electro-motive =ce2 & z its int]nal resi/ance is v l[ x w furni% a /eady curr5t = sev]al h\rs4 ,any numb] ( ^! cells may be made & connect$ 9 s]ies2 b :5 n 9 use x w\ld be well to remove & wa% ! z9cs4 ,any bi*romate batt]y w answ] v well = plat+1 ! ,gr5et be+ an especially good "o4 ,a well-amalgamat$ z9c plate =ms "o pole1 & a pair ( c>bon plates1 "o on ea* side ( ! z9c & jo9$ at ! top1 make up ! o!r pole4 ,:5 n 9 use ! entire plunge "p %\ld be remov$ f ! bi*romate solution1 r9s$ (f 9 wat]1 & laid across ! top ( ! j>1 ready = its next employm5t4 ,! z9c & c>bons mu/ be jo9$ toge!r s t !y are well insulat$1 & ) no *ance ( ! z9c com+ into contact ) ! c>bons4 ,?is may be done ) f\r pieces ( h>d-wood soak$ 9 hot p>aff9e & !n lock$ toge!r ) /ove-bolts & nuts1 z %[n at ,fig4 #ab4 ,holes mu/ be made 9 ! top corn]s ( ! c>bons & z9c1 & ) small bolts & nuts ! connect+ wires c be made fa/4 ,to *>ge ?is batt]y1 add five fluid ounces ( sulphuric acid to ?ree p9ts ( cold wat]1 p\r+ ! acid sl[ly into ! wat] & /irr+ x at ! same "t ) a glass or c>bon rod4 ,:5 ?is becomes cold1 aft] /&+ a few h\rs1 add six ounces ( f9ely pulv]iz$ bi*romate ( pota%4 ,mix ?is ?or\ghly1 & p\r "s ( ! solution into ! glass cell until x is ?ree-f\r?s full2 !n x w be ready to receive ! c>bons & z9c4 ,:5 arrang+ ! wood-clamps on ! c>bon & z9c plates x w\ld be well to make two ( ! clamps long] ?an ! o!rs s t !y w ext5d out f> en\gh to re/ on ! top edge ( ! j>4 ,to keep !m 9 position at ! middle ( ! j>1 not*es %\ld be cut at ! und]side ( ^! clamps1 s t !y w fit d[n ov] ! edge ( ! j>4 ,any numb] ( ^! cells may be connect$ toge!r to obta9 ! desir$ am\nt ( curr5t1 or electro-motive =ce4 ,o!r batt]ies suitable = electro-plat+ are ! ,edison prim>y1 ,taylor1 ,full]1 ,daniell1 gravity1 ,groves1 & ,m]d+]s4 ,all ( ^! may be pur*as$ at l>ge electrical equipm5t or supply h\ses4 ,! ,cleans+ ,process ,"o ( ! mo/ important op]ations ( ! plat+ process is to prop]ly cleanse ! articles to be plat$ be=e !y are plac$ 9 ! ba?4 ,:5 once clean$ ! surfaces ( ^! objects mu/ n be t\*$ ) ! f+]s1 or any du/y or greasy object2 o!rwise ! electro-deposit$ metal w n hold on ! surface1 b w peel (f1 9 "t1 or bli/]4 ,a v small trace ( =eign matt] is suffici5t to prev5t ! deposit f adh]+ to ! surface to be plat$2 !re=e1 great c>e mu/ be tak5 to elim9ate all trace ( any?+ t w\ld int]f]e ) ! p]fect transmission ( metallic molecules to ! prep>$ surfaces4 ,acids are *iefly employ$ to remove =eign matt] f new metallic surfaces2 & = copp]1 brass1 iron1 z9c1 gold1 & silv] a table is giv5 on page #bha :i* w %[ ! "r proportion ( acids to wat] 9 ord] to cleanse ! v>i\s metals4 ,9 ! foll[+ scale ! num]als /& = p>ts4 ,= example3 ! fir/ "o means #ajj p>ts wat]1 #ej p>ts nitric acid1 #ajj p>ts sulphuric acid1 & #b p>ts hydro*loric acid--mak+ 9 all #beb p>ts4 ,^! c be measur$ 9 a glass graduate4 ---------------------------------------- -------- ,nitric,sulphuric,hydro*loric ,wat] ,acid ,acid ,acid ---------------------------------------- -------- ,copp] & brass #ajj #ej #ajj #b ,gold #ajj 444 444 #ae ,silv] #ajj #aj 444 444 ,wr\ght-iron #ajj #b #h #b ,ca/-iron #ajj #c #ab #c ,z9c #ajj 444 #aj 444 ---------------------------------------- -------- ,twi/ a piece ( f9e copp] wire ab\t "p ( ! object to be clean$ & plat$2 !n dip x 9 ! acid & r9se (f 9 clean w>m or hot wat]1 & rub ! surface briskly ) a bru% dipp$ 9 ! liquid4 ,dip x aga9 sev]al times1 & r9se 9 ! same mann]2 !n1 :5 x is bright & clean1 place x 9 ! ba?1 twi/ ! loose end ( ! wire ar\nd ! negative rod1 & />t ! curr5t fl[+1 tak+ c>e t ! object is ?or\ghly imm]s$4 ,t>ni%$ gold or silv] articles may be clean$ by imm]s+ !m 9 a hot solution ( cyanide ( potassium2 or a /rong w>m solution ( c>bonate ( ammonia w loos5 ! t>ni% on silv]1 s t x c be bru%$ (f4 ,corrod$ brass1 copp]1 ,g]man-silv]1 & bronze %\ld be cleans$ 9 a solution compos$ ( sulphuric acid1 ?ree ounces2 nitric acid1 "o & ?ree-qu>t]s ounces2 & wat]1 f\r ounces4 ,?is soon loos5s & dissolves ! corrosion2 !n ! article %\ld be bru%$ (f1 dipp$ 9 hot wat]1 & r9s$4 ,!n replace x 9 ! solution = a m9ute or two & r9se aga91 :5 x w be ready = ! plat+-ba?4 ,corrod$ z9c %\ld be imm]s$ 9 a solution ( sulphuric acid1 "o ounce2 hydro*loric acid1 two ounces2 & di/ill$ or ra9 wat]1 "o gallon4 ,x %\ld be well bru%$ aft] ! acid has bitt5 (f ! corrosion4 ,ru/y iron or /eel %\ld be pickl$ 9 a solution ( sulphuric acid1 six ounces1 hydro*loric acid1 "o ounce1 & wat]1 "o gallon4 ,:5 ! ru/ has be5 remov$1 imm]se ! object 9 a solution compos$ ( sulphuric acid1 "o p9t1 & di/ill$ wat]1 "o gallon4 ,be=e ! acid is add$ to ! wat] dissolve "o-qu>t]-p\nd ( sulphate ( z9c 9 ! wat]2 !n add ! acid1 p\r+ x sl[ly & /irr+ ! wat]4 ,lead1 t91 pewt]1 & _! comp\nds may be cleans$ by imm]s+ !m 9 a hot solution ( cau/ic soda or pota%1 !n r9s+ 9 hot wat]4 ,take great c>e if cau/ic is us$1 z x w burn ! sk9 & tissues ( ! body4 ,d n let ! f+]s come into contact ) any cleans$ article1 because ! oily secretions ( ! body w /ick to ! metal & cause ! coat ( deposit$ metal to /rip (f or pres5t a spott$ appe>ance4 ,! ,plat+-ba? ,! object to be plat$ %\ld n t\* ! bottom or sides ( ! plat+-vat1 & x %\ld be f> en\gh away f ! anodes to avoid any possibility ( com+ into contact ) !m4 ,x w n d to place ! anode & ka?ode too close toge!r1 z ! plate w be deposit$ unev5ly2 ! ?ick] coat+ w appe> on ! p>ts close/ to ! anode4 ,nei!r %\ld !y be sep>at$ too f>1 z ! resi/ance ( ! cell is !reby increas$1 & ( c\rse ?is means a wa/e ( en]gy4 ,! k ( h[ to arrange ! anode & ka?ode is a matt] to be le>n$ by exp]i5ce1 b by c>efully wat*+ ! deposit x w n be a difficult matt] to det]m9e ! prop] positions4 ,= _m reasons ! glass tank is pref]able = amateur electro-plat+ "w1 s9ce ! objects may be wat*$ )\t di/urb+ _! electric connections & )\t remov+ !m f ! liquid4 ,a v good plan = ! copp] ba?1 :5 sph]ical1 cyl9drical1 or holl[ objects are to be plat$1 is to l9e ! inside ( ! tank ) /rips or a %eet ( copp]1 hung on hooks t w cat* on ! sides2 !n connect ! positive wire directly to ^! /rips4 ,) ?is arrangem5t b "o rod1 ! negative1 is 9 use1 & ! objects to be plat$ are susp5d$ f x4 ,x foll[s t ! objects w take up ! copp] deposit f all sides1 & a m ev5ly di/ribut$ coat+ w be ! result4 ,x is bett] to />t up ! curr5t gradually1 r ?an to put on at ! beg9n+ a l>ge am\nt ( electro-motive =ce4 ,by wat*+ ! "* ( ! deposit y c soon tell if y h ! prop] /r5g? ( curr5t4 ,if ev]y?+ is work+ prop]ly ! copp] deposit w h a beautiful fle% t9t2 b if ! curr5t is too /rong x takes on a d>k-r$ tone & resembles ! surface ( a brick4 ,?is is n "r1 & ! object mu/ be remov$ & wa%$ (f1 ! curr5t r$uc$1 & ! object replac$ 9 ! ba?4 ,:5 a suffici5tly heavy coat+ ( ! copp] has be5 appli$1 remove ! object & wa% ?or\ghly 9 runn+ or w>m wat] to free x f any rema9+ copp] fluid4 ,if ?is is n done ! surface1 9 dry+1 w turn a dull br[n1 & w h to be bitt5 (f ) ! acid solution = cleans+ copp]4 ,! f9] ! copp] deposit ! bett] & smoo!r x w be2 ! gra9 w be small]1 & x w n pres5t a r\gh surface1 :i* is always difficult to plate ov] ) silv] or gold1 unless a fro/$ effect is desir$4 ,non-conduct+ objects are usually plat$ ) copp] fir/1 & !n replat$ ) ! metal desir$ = ! f9al f9i%4 ,to make ! surface conductive1 f9ely p[d]$ black-lead1 or plumbago ( ! be/ k9d1 or f9ely pulv]iz$ gas-c>bon is bru%$ ov] ! surface4 ,?is mu/ be ?or\ghly done2 & if ! deposit is sl[ ab\t appe>+ at any spot x may be ha/5$ by t\*+ x ) ! end ( an insulat$ wire atta*$ to ! ma9 conductor4 ,?is1 ( c\rse1 w only answ] = objects /rong en\gh to /& ! bru%+ treatm5t2 x w n d = fl[]s1 insects1 & o!r delicate ?+s1 t are to be silv] or gold plat$4 ,^! %\ld be giv5 a film ( silv] by soak+ 9 a solution ( alcohol & nitrate ( silv]1 made by %ak+ two p>ts ( ! *emical into "o hundr$ p>ts ( gra9-alcohol1 ) ! aid ( heat & 9 a well-cork$ bottle4 ,:5 dry1 ! object %\ld be subject$ to a ba? ( sulphurett$ hydrog5 gas "u a hood4 ,! sulphurett$ hydrog5 is made by br++ a b> ( wr\ght-iron to a :ite-heat 9 ! kit*5 range or furnace fire1 & t\*+ x ) a /ick ( sulphur4 ,! iron w melt & drop l wax4 ,^! drops %\ld be collect$ 9 a bottle4 ,n[ p\r ov] !m dilut$ sulphuric acid1 "o "p acid to ?ree p>ts wat]1 & ! gas w at once rise4 ,x w be quickly recogniz$ by its odor1 :i* is simil> to t ( ov]-ripe eggs4 ,x c be l$ (f ?r\gh a tube to ! place :]e y wi% to use x1 & :5 ?r\gh1 ! op]ation ( gas-g5]ation may be /opp$ by p\r+ (f ! liquid4 ,all objects prep>$ 9 ?is way %\ld be giv5 a prelim9>y coat+ ( ?9 copp] be=e !y are plat$ ) any o!r metal4 ,silv]-plat+ ,plat+ 9 silv] is done 9 practically ! same way z describ$ = ! copp]+ process4 ,?9 /rips or %eets ( pure silv] are us$ = ! anodes1 & ! electrolyte is compos$ ( nitrate ( silv]1 cyanide ( potassium1 & wat]4 ,dissolve ?ree & "o-half ounces ( nitrate ( silv] 9 "o gallon ( wat]2 or if m wat] is ne$$ to fill ! tank1 add x 9 ! proportion ( ?ree & "o-half ounces ( ! nitrate to ea* gallon ( wat]4 ,dissolve two ounces ( cyanide ( potassium 9 a qu>t ( wat]1 & sl[ly add ?is to ! nitrate solution4 ,a precipitate ( cyanide ( silv] w be =m$4 ,keep add+ & /irr+ until no m precipitate is =m$1 b be c>eful n to get an excess ( ! cyanide 9 ! solution4 ,ga!r ?is precipitate1 & wa% x on filt]+-pap] by p\r+ wat] ov] x4 ,! filt]-pap] %\ld be roll$ 9 a funnel %ape ?us p]mitt+ ! wat] to run away & leav+ ! precipitate 9 ! pap]4 ,?is precipitate is to be dissolv$ 9 m cyanide solution1 & add$ to ! quantity 9 ! tank4 ,!re %\ld be ab\t two ounces ( ! potassium cyanide p] gallon ov] & above :at 0 orig9ally put 94 ,! silv] anodes %[ ! condition ( ! fluid4 ,if ! solution is 9 good ord] !y w h a cle>1 creamy appe>ance1 b w t>ni% or turn p9k if !re is n suffici5t free cyanide 9 ! solution4 ,! prop] /r5g? ( curr5t is indicat$ by ! appe>ance ( ! plat$ objects4 ,a cle> :ite surface %[s t ev]y?+ is all "r1 ! solution 9 prop] work+ ord]1 & ! prop] curr5t to d ! "w4 ,too mu* curr5t w make ! color ( ! ka?odes yell[ or gray1 :ile too little curr5t w act sl[ly & require a long "t to deposit ! silv]4 ,! adhesion ( silv]-plate is r5d]$ m p]fect by amalgamat+ ! objects 9 a solution ( nitrate ( m]cury1 "o ounce to "o gallon ( wat]4 ,aft] ! objects h be5 prop]ly cleans$ !y are imm]s$ 9 ?is solution = a m9ute1 !n plac$ 9 ! silv]-ba? & connect$ ) ! negative-rod1 s t ! electro-deposit+ action beg9s at once4 ,gold-plat+ ,! gold-ba? is made 9 ! same mann] z ! silv] "o j describ$1 ) ! exception t *loride ( gold is us$ 9 place ( ! nitrate ( silv] 9 ! fir/ solution4 ,?is solution mu/ be heat$ to #aej ,fahr5heit :5 ! process is go+ on2 or a cold ba? may be made ( wat]1 #ejjj p>ts2 potassium cyanide1 "o hundr$ p>ts2 & pure gold1 fifty p>ts4 ,! gold mu/ be dissolv$ 9 hydro*loric acid1 & add$ to ! wat] & potassium4 ,v pretty effects may be obta9$ 9 gold-plat+ by *ang+ ! tones f yell[ to a gre5i% hue by ! addition ( a little cyanide ( silv] to ! solution1 or by ! use ( a silv] anode4 ,a r$di% t+e may be _h by add+ a small portion ( sulphate ( copp] to ! solution1 or hang+ a small copp] anode beside ! gold "o4 ,9 ! hot gold-ba? ! articles %\ld be kept 9 motion1 or ! solution /irr$ ab\t !m ) a glass rod4 ,:5 ! solution is p]fectly balanc$ & work+ "r ! anodes %\ld be a cle> dead yell[1 & ! articles 9 process ( plat+ %\ld be ( ! same hue4 ,a gold-plat+ outfit is %[n 9 ,fig4 #ac1 & consi/s ( ! tank & ba?1 a cell1 & a resi/ance-coil 7,r71 ?r\gh :i* ! /r5g? ( ! curr5t is regulat$4 ,! curr5t1 pass+ out ( ! cell f ! c>bon 7,c71 is regulat$ ?r\gh ! resi/ance-coils 7,r7 by ! swit* 7,s74 ,f !nce x passes to ! rod f :i* ! anode 7,a7 is susp5d$1 across ! electrolyte 7,e7 to ! ka?ode 7,k71 on :i* ! metal is deposit$1 & !n returns ?r\gh ! negative wire to ! z9c 7,z7 9 ! cell4 ,if ! hot ba? is us$ ! gold solution may be conta9$ 9 a glaz$ e>!n j> or a porcela9-l9$ metal j> or kettle4 ,b if ! latt] is us$ c>e mu/ be tak5 to see t none ( ! enamel is *ipp$1 or a %ort-circuit w be e/abli%$ betwe5 ! rods4 ,?is j> or kettle may !n be plac$ on a gas-/ove1 & a !rmomet] %\ld be susp5d$ s t ! m]cury bulb is half an in* bel[ ! surface ( ! liquid1 z %[n at ,t 9 ,fig4 #ac4 ,z ! liquid simm]s or evaporates away a little wat] %\ld be add$ f "t to "t to keep ! bulk ( ! liquid up to its normal or orig9al quantity4 ,illu/ration3 ,,fig4 #ac ,nickel-plat+ ,! nickel-plat+ process is simil>1 9 a g5]al way1 to ! o!rs2 x is c>ri$ on 9 a cold ba?--t is1 at ! normal temp]ature1 )\t be+ heat$ or *ill$ artificially4 ,!re are a great _m =mul = ! nickel z well z = ! o!r ba?s1 b ! g5]ally accept$ "o is compos$ ( d\ble nickel ammonium-sulphate1 ?ree p>ts2 ammonium c>bonate1 ?ree p>ts2 & wat]1 "o hundr$ p>ts4 ,ano!r good "o is compos$ ( nickel sulphate1 nitrate1 or *loride1 "o "p2 sodium bisulphate1 "o "p2 & wat]1 tw5ty p>ts4 ,nickel anodes are us$ 9 ba? to ma9ta9 ! /r5g?1 & great c>e mu/ be tak5 to h ! ba? p]fectly balanc$--t is1 n too acid nor too alkal9e4 ,to te/ ?is1 h "s blue-&-r$ litmus pap]4 ,if ! blue pap] is dipp$ 9 an acid solution1 x w turn r$2 & back to blue aga9 if plac$ 9 an alkal9e solution4 ,if ! nickel solution is too /rong ) alkali1 a trifle m ( ! nickel salts mu/ be add$1 s t bo? ! r$-&-blue litmus pap]1 :5 dipp$ 9 ! liquid1 w n *ange color4 ,if ! ba? is too alkal9e1 x w give a disagreeable yell[i% color to ! deposit ( metal on ! ka?ode2 & if too acid1 ! metal w n adh]e prop]ly to ! ka?ode1 & w /rip1 peel1 or bli/] (f4 ,f9i%+ ,:5 ! articles h be5 plat$ !y w h a some:at diff]5t appe>ance to :at may h be5 expect$4 ,= in/ance1 copp]-plat$ articles w h a bright fle%y-p9k hue2 silv]1 an opaque creamy-:ite2 gold1 a dead lemon-yell[ color1 & nickel mu* ! appe>ance ( ! silv]1 b slightly blu] 9 its tone4 ,articles remov$ f ! ba? %\ld be %ak5 ov] ! ba? s z to remove ! solution2 !n !y %\ld be imm$iately plung$ into hot wat]1 r9s$ ?or\ghly1 & all[$ to dry sl[ly4 ,:5 a silv]$ or gild$ object is p]fectly dry x %\ld be rubb$ rapidly ) a bru% & "s f9e silv]-poli%+ p[d] until ! opaque :ite or yell[ gives place to a silv] or gold lu/re4 ,x w !n be ready = burni%+ ) a /eel burni%]1 or ! article may be left ) a fro/$ silv] or gold surface4 ,/eel burni%]s c be _h at any tool-supply h\se1 & :5 us$ !y %\ld be frequ5tly dipp$ 9 ca/ile soapy wat] to lubricate !m4 ,!y w !n glide smoo?ly ov] ! surface ( ! deposit$ metal1 driv+ ! gra9 d[n & mak+ x bright at ! same "t4 ,if ! soapy wat] 7 n us$ ! action ( ! h>d burni%] ov] ! plate w\ld h a t5d5cy to te> away ! film ( deposit$ metal4 ,! burni%] mu/ always be clean & bright1 o!rwise x w\ld scrat* ! plat$ articles2 &1 :5 n 9 use1 keep ! bright poli%+ surfaces wrapp$ 9 a piece ( oil$ flannel4 ,small articles1 su* z sleeve-buttons1 r+s1 /uds1 & o!r ?+s n l>g] ?an a tw5ty-five-c5t piece1 may be poli%$ by be+ tumbl$ 9 a sawdu/ bag4 ,a cotton bag is made1 ?ree feet long & six in*es 9 diamet]1 clos$ at "o end & half-fill$ ) f9e sawdu/4 ,! articles are !n put 9 ! bag & ! end clos$4 ,grasp ! ends ( ! bag ) bo? h&s1 z if to jump rope ) x2 !n sw+ x to & fro1 until ! articles h _h a good tumbl+4 ,look at !m to see if !y are bright en\gh2 if n1 keep up ! tumbl+4 ,:5 old "w is to be re-plat$1 or gone ov]1 x w be necess>y to remove all ( ! old plate be=e a really good job c be done4 ,9 "s cases x may be remov$ ) a scrat*-bru% or pumice-/one2 b1 z a rule1 x c be remov$ mu* quick] & m satisfactorily ) acids4 ,silv] may be remov$ f copp]1 brass1 or ,g]man-silv] ) a solution ( sulphuric acid1 ) "o ounce ( nitrate ( pota% to ea* two qu>ts ( acid4 ,/ir ! pota% into ! acid1 !n imm]se ! article4 ,if ! action becomes weak be=e ! silv] is all (f1 !n heat ! solution & add m ( ! pota% 7saltpetre74 ,gold may be remov$ f silv] by heat+ ! article to a *]ry-r$1 & dropp+ x into dilut$ sulphuric acid--"o "p acid to two p>ts wat]4 ,?is w cause ! gold to peel & fall (f easily4 ,electrotyp+ ,! t]m electrotyp+ is int]pret$ 9 sev]al ways1 b1 9 g5]al1 x means ! process ( electro-plat+ an article1 or mold1 ) a metal coat+1 g5]ally copp]1 ( suffici5t ?ickness1 s t :5 x is remov$1 or sep>at$ f its orig9al1 x =ms an indep5d5t object :i*1 to all appe>ances1 w be a fac-simile ( ! orig9al4 ,to obta9 a positive copy a ca/ has to be tak5 f a negative or rev]se4 ,?is negative is call$ ! mold or matrix1 & c be ( pla/]1 glue1 wax1 or o!r compositions4 ,!re are a numb] ( processes 9 use1 b ! ,adams process 7no relation to ! au?or7 w give a boy a cle> idea ( ?is electro-*emical & me*anical art4 ,?is process 0 pat5t$ 9 #ahgj1 & is said to give a p]fect conduction to wax & o!r molds1 ) great] c]ta9ty & rapidity ?an any o!r1 & w accompli% 9 a few m9utes t :i* plumbago 7black-lead7 alone w\ld require f two to f\r h\rs to effect4 ,z appli$ to ! electrotyp+ ( type1 & cuts = illu/ration1 ! w>m wax impression is tak5 by press+ ! *ase or =m ( type into a b$ ( wax by p[] or hydraulic pressure4 ,!n remove x1 & :ile ! wax is /ill w>m1 p[d]$ t91 bronze1 or :ite bronze p[d] is freely du/$ all ov] x ) a s(t hair-bru%1 until ! surface pres5ts a bright1 metallic appe>ance4 ,! sup]flu\s p[d] is !n du/$ (f1 & ! mold is imm]s$ 9 alcohol1 & aft]w>ds wa%$ 9 wat] to remove ! air f ! surface4 ,x is !n plac$ 9 ! copp] ba? & ! connection made f ! negative pole to ! face ( ! mold1 s t ! curr5t w fl[ ov] its entire surface4 ,a deposit ( copp] w quickly appe>1 & become heavi] z ! mold is left 9 long]4 ,:5 a mold has receiv$ ! requir$ deposit x %\ld be tak5 f ! ba? & ! copp] film remov$ f x4 ,?is is done by plac+ ! mold 9 an incl9$ position & pass+ a /ream ( hot wat] ov] ! back ( ! copp] film4 ,?is s(t5s ! wax & enables "o to /rip ! film (f1 tak+ c>e at ! same "t n to crack or b5d ! ?9 copp] positive4 ,! ?9 coat+ ( wax1 :i* adh]es to ! face ( ! copp]1 c be remov$ by plac+ x1 face up1 on a wire rack & p\r+ a solution ( cau/ic pota% ov] x1 :i*1 9 dra9+ ?r\gh1 w fall into a vessel or tank b5ea? ! rack4 ,! pota% dissolves ! wax 9 a %ort "t1 & ! electro-deposit$ %ell may !n be r9s$ 9 sev]al *anges ( cold wat]1 or held "u ! faucet until ?or\ghly fre$ f ! cau/ic4 ,z _m1 if n all1 ( ! *emicals us$ 9 ! v>i\s plat+ processes1 & also ! clean+ fluids1 are highly poison\s1 great c>e %\ld be tak5 :5 h&l+ !m4 ,d n let ! f+]s or h&s come 9 contact ) cau/ic solutions or cyanide ba?s4 ,nev] use any ( ^! solutions if y h rec5tly cut y\r f+]s or h&s1 & d n all[ ! cyanides or cau/ics to get "u ! f+]-nails4 ,nev] add any acid to liquids conta9+ cyanide or f]ro-cyanide :ile 9 a clos$ room4 ,?is %\ld always be done 9 ! op5 air1 :]e ! fumes c pass away1 = ! gases :i* rise f ^! admixtures are poison\s :5 inhal$4 ,*apt] ,,xii ,,miscellane\s ,,app>atus ,! field ( appli$ electricity is su* a wide "o z to preclude any exhau/ive h&l+ ( ! subject 9 a book ( ?is size4 ,! aim has be5 to acqua9t ! "y /ud5t ) ! basic pr9ciples ( ! sci5ce1 & x is 8 "p to develop ^! pr9ciples along ! l9es indicat$ 9 ! prec$+ pages4 ,b !re are "s practical applications t may be prop]ly gr\p$ "u ! head+ ( ?is *apt]4 ,!y may s]ve z a /imulus to ! inv5tive faculties ( ! y\?ful exp]im5t]1 & s9ce ! pieces ( app>atus n[ to be describ$ are useful 9 !mselves1 ! "t sp5t 9 _! con/ruction w n be wa/$4 ,a ,rot>y ,glass-cutt] ,:5 mak+ a circle ( glass x is g5]ally be/ to let a glazi] cut ! disk1 o!rwise _m panes are likely to get brok5 be=e ! "y workman succe$s 9 gett+ out a p]fect "o4 ,b ) a rot>y glass-cutt] ! task is a comp>atively simple "o1 & ! tool is really an indisp5sable piece ( app>atus 9 e electrician's kit4 7,see ,figs4 #a & #b47 ,! wood5 =m is turn$ f p9e or :ite-wood1 & is ?ree in*es 9 diamet] at ! l>ge end1 or bottom1 "o in* 9 diamet] at ! top1 & two in*es high4 ,x is cov]$ ) felt held on ) glue4 ,directly 9 ! middle ( ! top a small hole is bor$ "o-eigh? ( an in* 9 diamet]1 & 9 ?is ap]ture an awl or m>k] is plac$1 h&le up1 z %[n 9 ,fig4 #b4 ,notice t ! awl is n made fa/ to ! =m1 b is removable at pleasure4 ,a h>d brass /rip twelve in*es long1 five-eigh?s ( an in* wide1 & "o-eigh? ( an in* ?ick is cut at ! end to receive a /eel-:eel glass-cutt]1 z %[n at ! foot ( ,fig4 #a4 ,a numb] ( "o-eigh?-in* holes are bor$ along ! /rip1 & half an in* ap>t1 measur+ f c5tre to c5tre4 ,to cut a disk ( glass ! =m is plac$ at ! c5tre ( ! pane1 ! latt] be+ impos$ on a smoo? table-top ov] a piece ( clo?4 ,! /rip1 or arm1 is laid on ! =m1 & ov] a small wa%]1 s t "o ( ! holes l9es ) t 9 ! =m4 ,! awl is pass$ d[n ?r\gh ! /rip & into ! block1 & ! cutt] is arrang$ 9 ! slot at ! end ( ! arm4 ,press d[n lightly on ! h&le ( ! awl1 to keep ! =m f slipp+2 !n ! cutt] is drawn ar\nd ! glass1 describ+ ! circle1 & cutt+ ! surface ( ! glass1 z %[n by ! solid l9e 9 ,fig4 #d4 ,! disk mu/ n be remov$ f ! pane until ! m>g9 is brok5 away4 ,) a /raight-edge & a cutt] score ! glass across ! corn]s1 z indicat$ by ! dott$ l9es 9 ,fig4 #d2 !n tap ! glass at ! und]side along ! l9e & break (f ! corn]s4 ,aft] ! corn]s h be5 remov$ tap ! glass aga91 foll[+ ! l9e ( ! circle2 !n break away ! rema9+ fragm5ts & smoo? ! edge4 ,illu/ration3 ,,fig4 #a ,,fig4 #b ,,fig4 #c ,,fig4 #d ,,fig4 #e ,,fig4 #f ,,glass-,,cutt+ ,,appliances ,to ,smoo? ,glass ,edges ,to smoo? ! r\gh edge ( glass !re are sev]al me?ods4 ,! simple/ way is to hold ! disk or /raight-edge aga9/ a f9e gr9d/one & use pl5ty ( wat]4 ,! glass mu/ be held edgewise1 z %[n 9 ,fig4 #e1 & n flatwise1 z %[n 9 ,fig4 #f4 ,to prop]ly gr9d a disk two workm5 are necess>y1 "o to turn ! /one1 & ! o!r to hold ! disk by spread+ ! h&s & grasp+ x at ! middle on bo? sides 7see ,fig4 #e74 ,9 ?is mann] ! glass may be held securely1 & sl[ly turn$1 s t an ev5 surface w be gr\nd4 ,:5 ! flat edge is smoo!d1 tilt ! glass fir/ to "o side & !n ! o!r1 & gr9d (f ! %>p edges4 ,ano!r me?od is to lay ! glass on a table1 ^u a piece ( felt or clo?1 & all[ ! edge to project ov] ! table = two or ?ree in*es4 ,hold ! glass d[n ) "o h& to prev5t its slipp+2 !n1 ) a piece ( corundum1 or a r\gh :et/one & glyc]9e1 "w d[n ! edge until x is smoo?1 turn+ ! glass cont9ually s t ! edge y are work+ on hangs ov] ! table4 ,?is process ( gr9d+ is some:at t$i\s1 b p]sev]ance & pati5ce w w9 out4 ,to ,cut ,holes 9 ,glass ,holes may be cut 9 glass 9 sev]al ways by an exp]t1 b ! boy :o is a novice 9 ?is l9e %\ld /ick to sl[ & sure me?ods & take no *ances4 ,=tunately1 glass is little us$ 9 voltaic electricity1 b x is indisp5sable 9 ! con/ruction ( ! frictional ma*9es1 ,leyd5-j>s1 & cond5s]s1 :]e glass is us$ z ! dielectric1 also = ! cov]+-plates to in/rum5ts4 ,! simple/ me?od is t ( rotat+ a copp] tube =w>d & backw>d ov] ! glass1 us+ f9e em]y du/ = ! cutt+ m$ium & oil ( turp5t9e z a lubricant4 ,! copp] tube mu/ be held 9 a rack1 s t its location w n %ift dur+ ! rotat+ or cutt+ motion4 ,! rack 9 :i* ! tube is held may be ( any size1 b to take a disk or squ>e ( glass1 tw5ty in*es across1 ! frame %\ld be tw5ty-two in*es long1 t5 in*es wide1 & twelve in*es high1 z %[n 9 ,fig4 #c4 ,! side-plates are elev5 in*es high & t5 in*es wide1 ! top is tw5ty-two in*es long & t5 in*es wide1 :ile ! "u l$ge is tw5ty & a qu>t] in*es long by t5 in*es wide4 ,?is frame is put toge!r ) glue & screws4 ,across ! back1 f ! corn]s d[n to ! middle ( ! "u l$ge1 batt5s or braces are made fa/ to prev5t ! frame f rack+4 ,a hole is made ?r\gh ! middle ( ! top & "u l$ge = ! copp] tube to pass ?r\gh4 ,if diff]5t-siz$ tubes are to be us$1 blocks to fit ! top & "u bo>d are to be cut & bor$1 s t !y may be held 9 place ) screws :5 9 use4 ,to cut a hole 9 glass1 place ! disk or pane on a felt or clo?-cov]$ table1 & ov] x arrange ! frame1 s t ! tube w re/ on ! spot to be drill$4 ,drop ! copp] tube d[n ?r\gh ! hole1 hav+ fir/ spread ! bottom ( ! tube slightly1 s t x w n split ! glass4 ,n[ put "s em]y inside ! tube s t x w fall on ! glass2 !n place a wood5 plug 9 ! top ( ! tube & arrange an awl1 or h&-plate1 s t ! tube may be press$ d[n4 ,take "o turn ab\t ! tube ) a l95 l9e1 or gut-?ong1 & make ! ends fa/ to a b[1 s t x w draw ! /r+ taut b n too tight4 ,lubricate ! foot ( ! tube ) oil ( turp5t9e1 & draw ! b[ back & =?4 ,at fir/ ! motion w cause ! copp] to scrat* ! glass1 & !n cut x1 until f9ally a p]fectly drill$ hole is =m$4 ,dur+ ! op]ation bo? glass & frame mu/ be held securely1 & ! b[ drawn ev5ly & )\t any j]k+ motion4 ,holes ( diff]5t sizes may be cut ) tubes ( v>i\s diamet]s4 ,small holes may be cut ) a highly temp]$ /eel-drill & glyc]9e1 ! drill be+ held 9 a h&-drill+ tool or 9 a brace4 ,anti-hum ,device = ,metallic ,l9es ,9 ov]head wires1 :]e galvaniz$ or h>d copp] wire is us$1 ! hum due to ! t5sion ( ! wires1 & ! w9d bl[+ ?r\gh !m1 causes a musical vibration :i* becomes mo/ annoy+ at times4 ,?is c be ov]come by a simple device kn[n z an 8anti-hum40 ,x consi/s ( a knob made ( wood or rubb]1 ?r\gh :i* a hole is bor$1 & ar\nd :i* a groove is cut4 ,"o end ( ! wire is pass$ ?r\gh ! hole & a loop =m$1 ! loose end be+ wrapp$ ab\t ! incom+ wire4 ,! o!r end ( ! l9e is pass$ ar\nd ! knob 9 ! groove1 & ! end twi/$ ab\t ! l9e-wire4 ,! knob is !n an insulator & a s\nd-dead5] at ! same "t4 ,to complete ! metallic circuit a loop ( wire is pass$ "u ! knob1 ! ends ( :i* are made fa/ to ! l9e-wires1 z %[n at ,fig4 #g4 ,illu/ration3 ,,fig4 #g ,illu/ration3 ,,fig4 #h ,a ,reel-c> = ,wire ,x is n always conv5i5t nor possible to c>ry ab\t a heavy roll ( wire :5 hang+ a l9e1 especially if x is ,no4 #ab galvaniz$ wire1 ( :i* !re are f fifty to a hundr$ p\nds 9 "o roll4 ,wire %\ld be unw\nd z x is paid out1 & n slipp$ (f f ! coil1 s9ce x is liable to k9k2 !re=e1 "s portable means ( transport+ x %\ld be provid$4 ,l9e-wires ov] long di/ances are paid out f a reel-truck drawn by horses4 ,= ! use ( ! amateur electrician ! reel-c> %[n 9 ,fig4 #h %\ld meet all requirem5ts4 ,! reel is made f two six-in* bo>ds1 a b>rel-head or a r\nd plat=m ( bo>ds1 f\r trunk-roll]s1 & a bolt4 ,f a six-in* bo>d cut two pieces five feet long4 ,eighte5 in*es f ei!r end cut "o edge away s z to =m h&les1 z %[n at ,c ,c ,c ,c 9 ,fig4 #h1 r\nd+ ! upp] & "u edges to take (f ! %>p corn]s4 ,cut f\r cross-pieces sixte5 in*es long2 & f two-by-f\r-in* spruce joi/ cut f\r legs twelve in*es long1 & plane ! f\r sides4 ,nail two ( ! cross-pieces to ! legs2 !n nail on ! side-bo>ds & s =m ! frame ( ! reel4 ,bore a half-in* hole ?r\gh a piece ( joi/2 !n nail x betwe5 ! rema9+ two cross-bo>ds1 tak+ c>e to get x 9 ! c5tre1 z %[n at ,a4 ,arrange ^! pieces at ! middle ( ! frame1 mak+ !m fa/ ) nails driv5 ?r\gh ! side-bo>ds & into ! ends ( ^! cross-pieces4 ,drive "s pieces ( mat*$ bo>ds toge!r1 & ) a /r+1 a nail1 & a p5cil describe a circle tw5ty in*es 9 diamet]4 ,) a compass-saw cut ! bo>ds on ! l9e1 & jo9 !m ) f\r batt5s made fa/ at ! und]side ) nails4 ,d n make ! batt5s s t !y w ext5d out to ! edge ( ! circle1 b keep !m 9 an in* or two1 s t ! "u edge ( ! turn-table w re/ on f\r trunk-roll]s screw$ fa/ to ! top edges ( ! side-bo>ds & end cross-pieces1 z %[n at ,b4 ,a half-in* bolt is pass$ d[n ?r\gh a hole made at ! middle ( ! table1 & ?r\gh ! block4 ,betwe5 ! block & ! und]side ( ! table sev]al l>ge iron wa%]s %\ld be plac$ on ! bolt1 s t !y w keep ! table slightly above ! roll]s1 ! ma9 weight ( ! table & its load ( wire be+ held by ! middle cross-brace4 ,! object ( ! trunk-roll]s is to relieve ! side /ra9 on ! bolt1 & also to prev5t friction betwe5 ! edge ( ! table & ! frame1 9 case ! t5sion on ! wire pulls x to "o side4 ,bore six holes 9 ! table1 on a circle ( twelve in*es1 & drive h>d-wood pegs 9 !m1 z %[n 9 ,fig4 #h4 ,:5 a roll ( wire is ly+ on ! table two boys c easily lift & c>ry ! c>1 & z !y d s ! wire w pay out4 ,give all ! wood-"w a coat ( d>k-gre5 pa9t1 & oil ! trunk-roll]s & ! wood :]e ! bolt passes ?r\gh4 ,a pair ( nuts %\ld be plac$ on ! l[] end ( ! bolt & a wa%] "u its head4 ,^! lock-nuts mu/ be screw$ on ) two monkey-wr5*es1 =c$ 9 opposite directions1 s t "o nut w be driv5 tightly aga9/ ! o!r4 ,?is is to prev5t ! turn+ ( ! table f unscrew+ ! nuts4 ,insulators ,= telegraph & telephone l9es1 :]e pole1 tree1 or build+ atta*m5ts are necess>y1 insulators mu/ be us$ to c>ry ! wires )\t loss ( curr5t4 ,! regul> glass1 porcela91 or h>d rubb] insulators1 made = pole & bracket use1 are ( c\rse ! be/4 ,!y c be pur*as$ at any supply-h\se = a few c5ts ea*1 b !re are o!r devices :i* w answ] equally well & :i* w co/ little or no?+4 ,obta9 "s bottles ( /\t glass1 ! gre5 or d>k glass be+ ! t\ghe/2 !n c>efully break ! bottle "p away4 ,9 do+ ?is hold ! bottle by ! neck1 ) a piece ( old clo? wrapp$ ab\t x1 to prev5t ! glass *ips f fly+4 ,save all ( ! neck & "p ( ! %\ld]1 z %[n 9 ,fig4 #i1 s t ! wire & its an*or+ loop w n slip (f & fall d[n on ! peg or cross-tree4 ,h>d-wood pegs cut f /icks "o in* & a half squ>e %\ld be :ittl$ d[n s t !y w fit 9 ! neck & come up to ! top4 ,! pegs %\ld be long en\gh at ! bottom to p]mit ( _! be+ fa/5$ to ! support+ poles1 trees1 or build+4 ,9 ,fig4 #aj ?ree ways ( atta*+ insulators are %[n4 ,at ,a ! peg is nail$ to ! top ( a pole1 or a hole is bor$ 9 ! pole & ! peg driv5 d[n 9 x4 ,at ,b two /icks ) peg ends are nail$ to a pole 9 ! =m ( a ,v1 & across ! /icks a cross-brace is made fa/ to prev5t ! /icks f spread+ or dropp+ d[n4 ,?is cross-brace is made fa/ to bo? ! /icks & ! pole s z to =m a rigid triangle4 ,at ,c ! usual =m ( cross-tree1 or ,t brace1 is %[n4 ,! pegs may be nail$ to ! face ( ! cross-plate1 or holes may be bor$ 9 ! top & ! pegs driv5 d[n into !m4 ,if ! cross-piece is m ?an two feet long1 bracket-iron %\ld be screw$ fa/ to ! pole & brace at bo? sides1 z %[n at ,c4 ,:]e a cross-plate is made fa/ to a pole1 a lap %\ld be cut out s t ! plate c lie aga9/ a flat surface r ?an on a r\nd "o 7see ,d 9 ,fig4 #aj74 ,! %\ld] ( ! bottle-necks mu/ n re/ on a cross-piece1 or t\* any?+ t w\ld lead to ! gr\nd or to o!r wires4 ,! %\ld] acts z a coll>1 & s %$s wat] t 9 wet wea!r ! curr5t _c be gr\nd$ ?r\gh ! ra94 ,! und]side ( ! coll> %\ld always be dry1 & also t "p ( ! peg protect$ by ! coll>1 !reby insur+ aga9/ ! loss ( curr5t4 ,! relative position ( insulator & peg is %[n at ,fig4 #i1 & if ! pegs are cut c>efully ! bottle-necks %\ld fit !m accurately4 ,jo9ts & ,splices ,x is ess5tial 9 electrical "w to h jo9ts1 splices1 unions1 & contacts made p]fectly tight1 s t ! curr5t w fl[ ?r\gh !m un9t]rupt$ly4 ,a poor contact or weak jo9t may ?r[ a :ole sy/em out ( ord]4 ,= ?is reason all jo9ts %\ld be sold]$ :]ev] practicable4 ,9 l9e "w1 h[ev]1 ?is is impossible1 except :]e trolley-wires are jo9$1 & ^! are braz$ 9 ! op5 air by an app>atus especially design$ = ! purpose4 ,9 telegraph & telephone l9es p]fect contact is absolutely necess>y1 & :]e atta*m5ts are made to insulators ! ma9-l9e %\ld nev] be turn$ ar\nd ! insulator4 ,! wire is br\ght up aga9/ ! insulator1 & ) a ,u wire ! ma9-l9e is tightly b\nd to x1 z %[n at ,fig4 #aa4 ,if x is necess>y to b9d ! ma9-l9e m securely to ! insulator1 "o or two turns may be tak5 ar\nd ! insulator ) ! ,u or an*or+ wire2 !n ) a pair ( ply]s a tight wrap is made4 ,:5 jo9+ two ends ( wire toge!r1 nev] make loops z %[n 9 ,fig4 #ab ,a4 ,?is con/ruction gives poor contact1 = ! wire loops w we> & f9ally break ap>t4 ,moreov]1 ! ru/ t =ms betwe5 ! loops w (t5 cause an op5 circuit & "o difficult to locate4 ,c>e mu/ be tak5 to make all splices secure & ) p]fect contact ( wires1 & ! only mann] 9 :i* ?is c be done is to pass ! ends ( wires toge!r = ?ree or f\r in*es1 z %[n 9 ,fig4 #ab ,b4 ,illu/ration3 ,,fig4 #i ,illu/ration3 ,,fig4 #aj ,illu/ration3 ,,fig4 #aa ,illu/ration3 ,,fig4 #ab ,illu/ration3 ,,fig4 #ac ,grasp "o wire ) a pair ( ply]s1 & ) ! f+]s />t ! coil or twi/1 !n ) ano!r pair ( ply]s f9i% ! wrapp+ ev5ly & snugly4 ,treat ! o!r end 9 a simil> mann]1 & z a result y w h ! splice pictur$ 9 ,fig4 #ab ,b1 ! _m wraps insur+ p]fect contact4 ,?is same me?od is to be employ$ = inside wires1 & aft] ! wrap is made heat ! jo9t & t\* x ) sold]+ solution4 ,! sold] w run 9 betwe5 ! coils & p]man5tly unite ! jo9t4 ,! b>e wires %\ld !n be cov]$ ) adhesive tape4 ,avoid %>p turns & angles 9 l9es1 & :]e x is n possible to arrange !m o!rwise x w\ld be well to put 9 a curv$ loop1 z %[n at ,fig4 #ac4 ,a repres5ts a pole1 ,b ,b ! l9e1 & ,c ! qu>t]-circul> loop let 9 to avoid ! %>p turn ab\t ! insulator4 ,! curr5t w pass ar\nd ! angle z well z ?r\gh ! loop1 b a galvanomet] te/ w\ld %[ t ! great] curr5t pass$ ?r\gh ! loop & avoid$ ! %>p turn4 8,gr\nds0 ,illu/ration3 ,,fig4 #ad ,illu/ration3 ,,fig4 #ae ,illu/ration3 ,,fig4 #af ,9 ! *apt] on wireless telegraphy sev]al good 8gr\nds0 7 describ$1 any "o ( :i* w\ld be admirably adapt$ to telegraph or telephone circuits4 ,9 ,figs4 #ad1 #ae1 & #af are illu/rat$ ?ree o!r 8gr\nds0 t c easily be made f inexp5sive mat]ial4 ,! fir/ "o1 ,fig4 #ad1 is an ord9>y t9 pan ) ! wire sold]$ to ! middle ( ! bottom4 ,! wire mu/ be sold]$ to be ( use1 z ! pan w\ld soon ru/ ar\nd a simple hole & make ! 8gr\nd0 a high-resi/ance "o4 ,if ! pan is buri$ deep en\gh 9 ! e>?1 & bottom up1 x w la/ = sev]al ye>s1 or s long z ! air does n get at x to induce corrosion4 ,! />-%ap$ 8gr\nd0 is cut f a piece ( %eet z9c1 copp]1 or brass1 & is ab\t twelve in*es 9 diamet]4 ,! wire is sold]$ to ! middle ( x1 & x is buri$ f\r feet deep1 ly+ flat at ! bottom ( ! hole4 ,9 ,fig4 #af a pail or l>ge t9 c is %[n ) ! wire pass+ d[n ?r\gh ! int]ior & f9ally rea*+ ! bottom1 :]e x is sold]$ fa/4 ,! c is fill$ ) small *unks ( c>bon1 or *>coal1 & "s holes are pun*$ ar\nd ! out] edge & bottom to let ! wat] out4 ,! c is !n buri$ ?ree or f\r feet 9 ! gr\nd4 ,use no?+ b copp] wire = 8gr\nds10 & x %\ld be heavy--no?+ small] ?an ,no4 #ad4 ,! wire %\ld be well insulat$ d[n to & bel[ ! surface = a foot or two1 s t p]fect action w take place & a complete 8gr\nd0 secur$4 ,! ,edison ,roa*-kill] ,:5 ,edison 0 a boy he inv5t$ ! fir/ electrocution app>atus on record4 ,at a c]ta9 /ation on ! ,gr& ,trunk ,railroad1 :]e ,edison 0 employ$ z a telegraph op]ator1 ! roa*es 7 s ?ick t at night !y w\ld crawl up ! p>tition betwe5 ! w9d[s & rea* ! ceil+1 :]e !y w\ld g to sleep4 ,dur+ ! day !y 7 apt to become dizzy1 lose _! foot+1 & drop d[n on ! heads ( ! op]ators4 ,?is did n suit "y ,edison1 s he devis$ a s*eme = _! de/ruction4 ,:ile wat*+ a piece ( telegraph app>atus "o day1 he saw a roa* try to /ep f a b> *>g$ ) positive electricity to "o ?r\gh :i* a negative curr5t fl[$4 ,! insect's feet 7 moi/ & s made a connection betwe5 ! two b>s4 ,z a consequ5ce a %ort-circuit ( high t5sion pass$ ?r\gh its body & x dropp$ dead4 ,?is put an idea into ,edison's head1 & ! electrocution app>atus 0 soon 9 work+ ord]4 ,! 8kill]0 0 ! mo/ simple device "o c\ld imag9e1 & 0 compos$ ( two long1 n>r[ /rips ( heavy t9-foil pa/$ side by side on a smoo? bo>d1 ) a space ( "o-eigh? ( an in* betwe5 !m1 z %[n at ,fig4 #ag4 ,to "o /rip a positive wire 0 connect$1 :ile to ! o!r a negative or gr\nd 0 made fa/4 ,high-t5sion curr5t1 or t f an induction-coil1 0 connect$ ) ! wires1 & ! result+ voltage 0 /rong en\gh to give "o a sev]e %ock if ! f+]s ( "o h& 7 plac$ on "o plate & ^? ( ! o!r h& on ! o!r plate4 ,?is device 0 arrang$ across ! w9d[-cas+ 9 ! pa? ! roa*es 7 accu/om$ to travel on _! nightly trips up ! side wall4 ,x 0 n long aft] d>k be=e roa* numb] "o saunt]$ up ! wall1 cross$ ! "u /rip1 & /epp$ ov] on ! upp] "o4 ,b he w5t no f>!r1 & he1 ) _m ( 8 fri5ds & relations1 7 ga!r$ up 9 a du/-pan ! next morn+ & ?r[n into ! /ove4 ,illu/ration3 ,,fig4 #ag ,illu/ration3 ,,fig4 #ah ,9 electricity1 z 9 _m o!r ?+s1 simplicity is ! key-note ( success2 & f ?is little device to employ ! alt]nat+ curr5t = ridd+ a h\se ( an insect nuisance sprang ! grim app>atus kn[n z ! 8dea? *air10 us$ 9 ! execution ( fir/-degree crim9als 9 ! ,/ate ( ,new ,york4 ,_m p ?9k ! me*anism = electrocution is a complicat$ "o1 b x is q z simple z ! ,edison roa*-kill]4 ,"o pole is plac$ at ! head ( ! crim9al & ! o!r at ! feet1 ! latt] be+ b\nd fa/ s t p]fect contact c be _h4 ,!n an alt]nat+ curr5t ( fifte5 hundr$ to two ?\s& volts is run ?r\gh ! body1 & dea? is in/antane\s & void ( pa94 ,an ,electric ,m\se-kill] ,a modification ( ! simple roa*-kill] 0 rec5tly us$ by ! au?or 9 8 laboratory to get rid ( "s tr\blesome mice4 ,a piece ( bo>d 0 cut twelve in*es squ>e1 ! edges be+ bevell$ s t x w\ld be an easy matt] = ! mice to climb up on x4 ,an in*-wide circle ( %eet brass 0 prep>$ measur+ elev5 in*es outside diamet] & n9e in*es inside4 ,ano!r circle 0 cut measur+ eight in*es & a half outside & six in*es inside diamet]4 ,bo? circles 7 atta*$ to ! bo>d ) copp] tacks & poli%$ z bright z possible1 ! f9i%$ bo>d appe>+ z %[n 9 ,fig4 #ah4 ,wires 7 sold]$ to ea* /rip1 & ^! 9 turn 7 connect$ to a high-t5sion curr5t ( sev]al ?\s& volts4 ,crumbs & small pieces ( meat 7 plac$ on ! bo>d inside ! circles1 & ! trap 0 set 9 a conv5i5t place on ! floor ( ! laboratory4 ,! next morn+ sev]al mice lay dead on ! floor1 b at "s di/ance f ! bo>d1 & ?is seem$ a little my/]i\s4 ,! foll[+ night ! au?or work$ late 9 ! laboratory4 ,aft] f9i%+ :at he _h on h&1 he turn$ d[n ! lights & sat d[n & wat*$ ! trap4 ,pres5tly ,mr4 ,m\se appe>$ f some:]e4 ,he sniff$ ! air1 !n approa*$ clos] to ! bo>d1 sniff$ aga91 &1 evid5tly conclud+ t he 0 on ! "r trail1 he climb$ up ! side ( ! bo>d & /ood on ! out] /rip4 ,he plac$ "o =e-foot on ! inn] /rip1 &1 bang6 up he w5t 9 ! air1 & l&$ on ! floor a foot or m away4 ,8 jump into space 0 due to ! electric action on 8 muscles1 = ! curr5t lit]ally tore 8 n]v\s sy/em into %r$s4 ,mr4 ,m\se lo/ a great _m fri5ds & relatives t season 9 ! same mann]1 & ! app>atus is confid5tly recomm5d$ z a c]ta9 & humane ag5t = ! de/ruction ( all small v]m94 ,*apt] ,,xiii ,,frictional ,,electricity ,frictional electricity is high pot5tial1 curr5t alt]nat+1 & ( high voltage b v l[ amp]age4 ,ap>t f c]ta9 uses 9 laboratory & m$ical practice1 x is valueless4 ,9 its great] volume x is ak9 to ! lightn+-bolt & is dang]\s2 b 9 its small] volume x is a comp>atively h>mless toy4 ,f ! glass rod1 or ! amb]1 rubb$ on a catsk9 to ! mod]n /atic ma*9es is a long jump1 & ! p]iod ( exploitation cov]s c5turies ( int]e/+ exp]im5ts1 mo/ ( :i*1 h[ev]1 h be5 practically useless = any comm]cial purpose4 ,/atic or frictional electricity is g5]at$ by friction only1 )\t ! aid ( magnets1 coils ( wire1 or armatures rotat+ at high spe$4 ,! simple process ( ! glass & catsk9 has be5 v>i\sly modifi$1 until at la/ ,wim%ur/ inv5t$ & p]fect$ :at is kn[n z ! 8,wim%ur/ ,influ5ce ,ma*9e40 ,x is self-*>g+1 & does n require 8/>t+40 ,x w "w all ! ye> r\nd 9 any climate & temp]ature1 & is ! greate/ improvem5t ev] made 9 /atic electric ma*9es4 ,ap>t f its effici5cy "u all conditions1 x is ! simple/ ( all ma*9es to make1 & c easily be con/ruct$ by a boy :o is h&y ) tools1 & :o c obta9 ! glass & brass p>ts necess>y 9 its con/ruction4 ,! pr9cipal p>ts ( an influ5ce ma*9e are ! glass disks1 wood5 bosses1 driv+ pulleys & crank1 glass /&>ds1 brass arms ) ! sp>k-balls at ! ends1 & ! base ) ! uprights on :i* ^! p>ts are built up & held 9 position4 ,a ,wim%ur/ ,influ5ce ,ma*9e ,obta9 a /iff piece ( br[n pap] tw5ty in*es squ>e1 & ) a compass describe a circle tw5ty in*es 9 diamet]4 ,inside ( ?is circle make ano!r "o f\rte5 in*es 9 diamet]1 & ne> ! c5tre a ?ird circle six in*es 9 diamet]4 ,ano!r circle f\r in*es 9 diamet] %\ld be drawn inside ( ! six-in* circle1 s t :5 ! bosses are made fa/ to ! glass plates !y c be prop]ly c5tr$4 ,also m>k sixte5 l9es radiat+ f ! c5tre1 equal di/ances ap>t1 z %[n 9 ,fig4 #a4 ,f a deal] 9 glass pur*ase two cle>1 :ite panes ( glass eighte5 in*es squ>e4 ,be c>eful n to get ! gre5 glass1 z ?is is n ne>ly s good z ! :ite = /atic ma*9e con/ruction4 ,if x is possible to get cry/al plate s mu* ! bett]4 ,! panes %\ld be ?91 or ab\t "o-sixte5? ( an in* 9 ?ickness1 & free f bubbles1 wavy places1 scrat*es1 or o!r blemi%es4 ,f ^! panes cut two disks sixte5 in*es 9 diamet] ) a rot>y cutt]1 z describ$ 9 ! *apt] on ,miscellane\s ,app>atus1 page #bid1 & rub ! edges ) a wat]-/one 7see *apt] on ,=mul1 page #ccj47 ,f flat1 ?9 t9-foil cut ?irty-two w$ge-%ap$ pieces f\r in*es long4 ,!y %\ld be "o in* & a half wide at "o end & ?ree-qu>t]s ( an in* at ! o!r1 z %[n at ,fig4 #b ,a4 ,give ea* plate ( glass two ?9 coats ( %ellac on bo? sides2 !n lay "o on ! pap] patt]n 7,fig4 #a7 s t ! outside edge ( ! glass w lie on ! l>ge/ circle4 ,place a weight at ! middle ( ! glass to hold x 9 place2 !n make sixte5 ( ! t9-foil sectors fa/ to ! plate1 us+ %ellac z ! /ick+ m$ium4 ,b fir/ give "o side ( ea* sector a ?9 coat ( %ellac1 all[+ x to dry2 !n give x ano!r coat :5 apply+ x to ! glass4 ,! sectors are to be symmetrically arrang$ on ! glass1 us+ a l9e ( ! patt]n z a c5tre = ea* piece 7z %[n at ,a 9 ,fig4 #a71 & ! f\rte5 & six in* circles z ! out] & inn] b\nd>ies4 ,ea* piece1 z x is appli$1 %\ld be press$ d[n ^u ! glass1 s t x w /ick smoo?ly1 )\t air bubbles or creases4 ,a v good plan is to lay a piece ( s(t blott+-pap] ov] ! sector & drive x d[n ) a small squeegee-roll] su* z is us$ 9 photography1 tak+ c>e1 h[ev]1 n to %ift ! sector f its prop] position4 ,:5 all ! sectors are on1 ! plate %\ld appe> z %[n 9 ,fig4 #b4 ,aft] ! %ellac1 :i* holds ! sectors to ! glass1 is dry1 run a bru% full ( %ellac ar\nd ! inn] & out] extremities ( ! t9-foil /rips = half or ?ree-qu>t]s ( an in* 9 f ! ends4 ,! %ellac w hold ! sectors firmly to ! glass1 & w slightly insulate !m z well1 !reby prev5t+ ! escape ( electricity4 ,apply ! rema9+ sectors to ! o!r plate ( glass 9 a simil> mann]2 & z a result two disks ( glass1 ) ! appli$ /rips1 w be ready to m\nt 9 ! frame4 ,illu/ration3 ,,fig4 #a ,,fig4 #b ,,fig4 #c ,,fig4 #d ,,fig4 #e ,,fig4 #f ,,details ,,( ,,wim%ur/ ,,influ5ce ,,ma*9e ,a hole ?ree-qu>t]s ( an in* 9 diamet] %\ld be made 9 ea* glass plate1 s t a ?ree-eigh?s sp9dle may pass ?r\gh !m & into ! bosses1 s z to keep !m 9 prop] l9e4 ,x is pref]able1 h[ev]1 n to bore ^! holes if bosses & accurately bu%$ holes c be made 9 ! uprights ( ! frame :i* support ^! disks4 ,at a wood-work+ mill h two bosses made t w measure f\r in*es 9 diamet] at ! l>ge end1 & "o in* & a half at ! small "o4 ,!y %\ld be ( su* l5g? t :5 ! plates & two bosses are arrang$ 9 l9e 7to appe> z %[n 9 ,a ,a at ,fig4 #i7 !y w fill ! entire space betwe5 ! uprights ,b ,b4 ,ne> ! small end a groove is turn$ 9 ea* boss1 s t a r\nd lea!r belt w fit 9 x1 z %[n 9 ,fig4 #c4 ,! base is made f p9e1 :ite-wood1 cypress1 or any o!r wood t is s(t & easily work$4 ,x is compos$ ( two /rips tw5ty-f\r in*es long1 ?ree in*es wide1 & "o in* & a qu>t] 9 ?ickness1 & two cross-pieces f\rte5 in*es long1 ?ree in*es wide1 & "o in* & a half ?ick4 ,^! are put toge!r ) glue & screws1 & at bo? sides ( ! base not*es are cut to accommodate ! feet ( ! uprights4 ,! uprights are sev5te5 in*es high1 ?ree in*es wide1 & "o in* & a half ?ick4 ,! not* at ! foot ( ea* "o is cut s t1 :5 fitt$ 9 place1 ! foot ( ! upright w re/ on a table on a l9e ) ! bottom ( ! end cross-pieces "u ea* corn]4 ,at ! foot ( ! uprights a piece ( %eet rubb] %\ld be made fa/1 ) glue or %ellac1 s t :5 9 op]ation ! ma*9e w n move ab\t or slide4 ,a groove is cut at "o side ( ea* upright six in*es above ! bottom1 z %[n at ,fig4 #d ,a4 ,9 ?is groove ! driv+-:eel axles fit1 & ne> ! top holes are made 9 ! uprights ?r\gh :i* ! sp9dles pass1 :i* 9 turn support ! bosses & glass disks4 ,at ! middle ( ea* cross-piece =m+ ! ends ( ! base a "o-in* hole1 = ! glass /&>d rods1 is bor$ ?r\gh ! wood1 z %[n at ,fig4 #d ,b ,b4 ,aft] atta*+ ! uprights to ! base ) glue & screws1 & giv+ all ! wood-"w sev]al successive coats ( %ellac1 ! frame w be ready = its m\nt+s4 ,! driv+-:eels are ( wood sev5-eigh?s ( an in* ?ick & sev5 in*es 9 diamet]2 !y %\ld be turn$ on a la! & a groove cut 9 ! edge s t a r\nd lea!r belt w fit 9 x4 ,^! :eels are m\nt$ on a wood5 axle t c be made f a r\nd curta9-pole1 ) a half-in* hole bor$ ?r\gh its entire l5g?4 ,! axle is z long z ! di/ance betwe5 uprights ,b ,b 9 ,fig4 #i4 ,! :eels are to be arrang$ & glu$ fa/ to ! axle1 s t ! grooves w l9e directly "u ^? 9 ! bosses1 z %[n 9 ,fig4 #i4 ,a half-in* axle is driv5 ?r\gh ! hub1 & at "o end x is ?read$ & provid$ ) two wa%]s & nuts2 or a squ>e %\ld] & "o wa%] & nut may be us$1 s t a crank & h&le may be held fa/4 ,%ellac %\ld be put on ! %aft to make x hold fa/ 9 ! hub4 ,! complete app>atus ( :eels1 axle1 hub1 & h&le is %[n at ,fig4 #e1 & 9 ! frame ?is is s hung t ! iron axle re/s 9 ! grooves cut 9 ! uprights4 ,to hold ?is 9 place two metal /raps1 z %[n 9 ,fig4 #f1 are made & screw$ fa/ to ! wood4 ,:5 f9ally adju/$ ! driv+-:eels %\ld rotate freely :5ev] ! crank is turn$4 ,! wood5 bosses1 ,fig4 #c1 are giv5 two or ?ree coats ( %ellac2 !n !y are made fa/ to ! glass disks on ! same side to :i* ! t9-foil sectors are atta*$4 ,! disks %\ld be plac$ ov] ! pap] plan1 ,fig4 #a1 & s adju/$ t ! out] l9e tallies ) ! l>ge circle4 ,acetic glue#d is !n appli$ to ! flat surface ( ! boss1 & ! latt] is plac$ at ! middle ( ! disk to l9e ) ! small circle4 ,place a weight on ! end ( ! boss to hold x d[n1 & leave x = t5 or twelve h\rs or until ?or\ghly dry4 #d ,see ,=mul1 ,*apt] xiv41 = ! recipe ( acetic glue4 ,bo? bosses %\ld be set at ! same "t s t !y may dry toge!r4 ,if ! bosses are turn$ on a la! a hole %\ld be made 9 ea* "o ab\t half-way ?r\gh f ! small end4 ,?is1 9 turn1 %\ld be bu%$ or l9$ ) a piece ( brass tube1 :i* %\ld fit snugly 9 ! hole4 ,a little %ellac pa9t$ on ea* piece ( tube w make x /ick4 ,pieces ( /eel rod t w j fit )9 ! tub+ are to be cut long en\gh to ent] ! full l5g? ( ! hole1 pass ?r\gh ! holes made 9 ! top ( ! uprights1 & ext5d half an in* beyond1 z %[n 9 ,fig4 #i4 ,! bosses & axles w !n appe> z %[n 9 ,fig4 #g4 ,flat places %\ld be fil$ on ea* rod :]e x passes ?r\gh ! wood upright2 a set-screw w !n hold x fa/ & keep x f revolv+4 ,:5 ! hole1 or tub+1 is oil$ s t ! boss & disk w revolve freely on ! axle1 ! disks1 bosses1 & axles are ready to be m\nt$ 9 ! frame4 ,a r$ fibre wa%]1 su* z is us$ 9 faucets1 %\ld be made fa/ to "o glass disk at ! c5tre1 s z to sep>ate ! disks & prev5t !m f t\*+ :5 !y are revolv+ 9 opposite directions4 ,^! fibre wa%]s c be _h f a plumb] or pur*as$ at a h>dw>e /ore4 ,%ellac or acetic glue w hold ! wa%]s 9 place4 ,illu/ration3 ,,fig4 #g ,illu/ration3 ,,fig4 #h ,illu/ration3 ,,fig4 #i ,illu/ration3 ,,fig4 #aj ,m\nt "o disk by hold+ ! boss ) ! small end opposite a hole 9 "o upright1 & slip an axle ?r\gh f ! outside ( ! upright4 ,hold ! o!r disk 9 place1 & slip ! rema9+ axle ?r\gh ! o!r upright & into ! boss4 ,:5 bo? plates are 9 place & c5tr$1 turn ! set-screws d[n on ! flatt5$ axles to hold !m 9 place4 ,to r$uce ! friction betwe5 ! bosses & ! uprights x w\ld be well to place a fibre wa%] betwe5 !m4 ,a few drops ( oil on ^! wa%]s w lubricate !m prop]ly1 & all[ ! ma*9e to run easi]4 ,an end view ( ! app>atus1 z s f> assembl$1 w appe> z %[n 9 ,fig4 #i1 ,a be+ ! disks1 bosses1 & axles1 ,b ,b ! uprights support+ !m1 ,c ! hub1 & ,d ,d ! driv+-:eels4 ,! h&le & crank 7,e7 ext5ds out f> en\gh f ! side to all[ a free sw++ motion )\t hitt+ ! upright or base4 ,hav+ arrang$ ^! disks & :eels s z to revolve freely1 x w n[ be necess>y to con/ruct & add ! o!r vital p>ts & ! connect+ l9ks 9 ! *a9 ( ! complete work+ me*anism4 ,f a supply-h\se obta9 two solid glass rods an in* 9 diamet] & fifte5 in*es long4 ,^! fit 9 ! holes 7,b ,b7 bor$ 9 ! end-pieces ( ! base1 ,fig4 #d4 ,procure two brass balls1 two or two & a half in*es 9 diamet]1 su* z come on brass b$s1 & two %ort pieces ( brass tub+1 "o in* inside diamet]1 t w fit ov] ! ends ( ! rods4 ,^! tub+s are to be sold]$ fa/ to ! balls s t bo? tubes & balls w rema9 at ! top ( ! glass rods4 ,f brass rod ?ree-sixte5?s or a qu>t] ( an in* 9 diamet] make two =ks1 z %[n at ,fig4 #h1 & sold] small brass balls at ! ends ( ! rods4 ,! prongs ( ! =k are six in*es long & ! %ank f\r in*es 9 l5g?4 ,along ! inside ( ! =ks small holes are bor$1 & brass wires1 or 8po9ts10 are sold]$ fa/4 ,^! ext5d out = half an in* f ! rods1 & are kn[n z ! 8comb10 or collectors4 ,! =ks %\ld be s f> ap>t t :5 m\nt$ ) ! glass disks revolv+ betwe5 !m ! po9ts w n t\* or scrat* ! t9-foil sectors1 & yet be z close to !m z possible4 ,a hole %\ld be bor$ 9 ! brass balls1 & ! %ank ( ! =k pass$ ?r\gh & sold]$ 9 place1 z %[n 9 ,fig4 #aj4 ,a ?ree-eigh?-in* hole is bor$ directly 9 ! top ( ea* brass ball to hold ! quadrant rods1 :i* ext5d ov] ! top ( ! disks4 ,9 ! illu/ration ( ! complete ma*9e 7,fig4 #ab7 ! arrangem5t ( ! glass pill>s1 balls1 combs1 & quadrant rods is %[n4 ,! rods are ?ree-eigh?s ( an in* 9 diamet] & are loose 9 ! holes at ! top ( ! balls1 s t !y c be mov$ or %ift$ ab\t1 accord+ z to :e!r x is a left or a "r h&$ p]son :o may be turn+ ! crank4 ,at ! upp] end ( ea* rod a brass ball is sold]$1 "o be+ ?ree-qu>t]s ( an in* 9 diamet]1 ! o!r two in*es4 ,! project+ ends ( ! =ks %\ld be provid$ ) metal h&les or brass balls1 z %[n 9 ,fig4 #ab2 ^! may be slipp$ ov] ! end or sold]$ fa/4 ,obta9 two small brass balls ) %anks1 su* z screw on iron b$-po/s1 & h ! ext5d+ ends ( ! axles t support ! bosses ?read$1 s t ! balls w screw on !m4 ,bore a qu>t]-in* hole ?r\gh ea* ball1 & slip a brass rod ?r\gh x & sold] x fa/4 ,ea* end ( ^! rods %\ld be tipp$ ) a bun* ( t9sel or f9e copp] wires4 ,^! are ! 8neutraliz]s10 & ! ends are curv$ s t ! bru%es ( f9e wires w j t\* ! disks :5 ! latt] are revolv$1 z %[n 9 ,fig4 #ab4 ,! ball hold+ ! rod is to be screw$ fa/ to ! axle2 !n ! axle is pu%$ back into ! boss & made fa/ 9 ! head ( ! upright ) ! set-screw4 ,illu/ration3 ,,fig4 #ab ,! rod-&-ball at ! opposite side ( ! disks is arrang$ 9 a simil> mann]1 b ! rod po9ts 9 an opposite direction to t on ! fir/ side4 ,cord or lea!r belts connect ! driv+-pulleys & bosses1 ! belt on "o side runn+ up /raight ov] ! boss & d[n aga9 ar\nd ! driv+-pulley4 ,! belt at ! opposite side is cross$1 s t ! direction ( ! boss is rev]s$2 & 9 ?is mann] ! disks are made to revolve 9 opposite directions1 al?\gh ! driv+-pulleys are bo? go+ 9 ! same direction4 ,a portion ( ! sectors are omitt$ 9 ! illu/ration 7,fig4 #ab7 s t a bett] view ( ! work+ p>ts may be _h4 ,:5 ! disks are revolv+ ! accumulat$ electricity dis*>ges f "o ball to ! o!r1 above ! plates1 9 ! =m ( bright blue sp>ks suffici5tly p[]ful to puncture c>dbo>d if x is held midway betwe5 ! balls4 ,a ,l>ge ,leyd5-j> ,:5 exp]im5t+ ) ?is ma*9e x w\ld be well to h "o or m ,leyd5-j>s to accumulate /atic *>ges4 ,a l>ge "o ( consid]able capacity is easily made f a batt]y j>1 t9-foil1 brass rods & *a91 & "s o!r small p>ts4 ,obta9 a blue/one batt]y j>1 & aft] heat+ x to drive all moi/ure f ! surface1 give x a coat ( %ellac inside & out4 ,) t9-foil1 set ) %ellac1 cov] ! bottom & inside ( ! j> = two-?irds ( its height f ! bottom1 z %[n 9 ,fig4 #aa4 ,cov] ! outside & bottom 9 a simil> mann]1 & ! same height f ! bottom1 & provide a cork1 or wood5 cap1 = ! top4 ,if a l>ge1 flat cork _c be _h1 !n make a /opp] by cutt+ two circul> pieces ( wood1 ea* half an in* ?ick1 ! inn] "o to fit snugly )9 ! j>1 ! o!r to lap ov] ! edges a qu>t] ( an in* all ar\nd4 ,fa/5 ^! pieces toge!r ) glue1 z %[n at ,fig4 #ac1 & give !m sev]al good coats ( %ellac4 ,make a small hole at ! middle ( ?is cap & pass a qu>t]-in* rod ?r\gh x1 leav+ six in*es above & bel[ ! cap4 ,to ! top ( ! rod sold] a brass ball4 ,at ! foot a piece ( brass *a9 is to be made fa/1 s t sev]al l9ks ( x re/ on ! t9-foil at ! bottom ( ! j>4 ,to *>ge a j> f ! ,wim%ur/ ma*9e1 /& ! j> on a glass-legg$ /ool1 & connect a copp] wire betwe5 "o ( ! ov]head balls on ! ma*9e & ! ball at ! top ( ! rod 9 ! /opp] ( ! j>4 ,make ano!r wire fa/ to ! o!r ball at ! top ( ! ma*9e1 & place x "u ! j> s t ! t9-foil on ! bottom t\*es x4 ,by op]at+ ! ma*9e ! j> is *>g$4 ,to dis*>ge ! j> make a ,t-yoke1 z %[n at ,fig4 #ad1 by nail+ a brass rod fa/ to a wood5 h&le & sold]+ brass knobs1 or hamm]+ a lead bullet1 on ! ends ( ! rod4 ,hold "o knob aga9/ ! top knob ( ! j> & br+ ! o!r ne> ! foil coat+ at ! outside1 :5 a sp>k w jump f ! foil to ! knob ) a l\d snap4 ,a ,glass-legg$ ,/ool ,"o ( ! mo/ useful accessories 9 play+ ) frictional electricity w be a glass-legg$ /ool4 ,a /ool ) glass feet is p]haps too exp5sive = a boy to pur*ase1 b "o may be made at little or no co/ f a piece ( /\t plank1 f\r glass telegraph l9e-insulators1 & ! wood5 screw-p9s on :i* !y re/ :5 atta*$ to a pole4 ,illu/ration3 ,,fig4 #aa ,illu/ration3 ,,fig4 #ac ,illu/ration3 ,,fig4 #ad ,illu/ration3 ,,fig4 #ae ,illu/ration3 ,,fig4 #af ,! g5]al plan ( ! /ool is %[n at ,fig4 #ae1 & ! top measures twelve by fifte5 by two in*es4 ,"u ea* corn] a screw-p9 is made fa/ by bor+ a hole 9 ! wood & sett+ ! p9 9 glue4 ,! p9s are cut at ! top1 z %[n 9 ,fig4 #af1 & :5 !y are set 9 place ! glass insulators may be screw$ on4 ,! wood-"w %\ld be giv5 a few coats ( %ellac to l5d x a good appe>ance & help to insulate x4 ,!re are a great _m int]e/+ exp]im5ts t may be p]=m$ ) /atic or frictional electricity1 & ^! may be look$ up 9 ! text-books on electricity us$ 9 s*ool4 ,a ^w ( caution w n be misplac$4 ,rememb] t ! curr5t1 9 l>ge volume1 is dang]\s4 ,= example1 a s]ies ( *>g$ ,leyd5-j>s may conta9 en\gh electricity to give a v sev]e %ock to ! n]v\s sy/em ( ! p]son :o *ances to dis*>ge x4 ,its m$ical use %\ld be "u ! advice & sup]vision ( a physician4 ,*apt] ,,xiv ,,=mul ,9 ! con/ruction ( electrical app>atus !re are _m ?+s1 su* z pa9t1 cem5t1 non-conduct+ comp\nds1 & acid-pro( sub/ances1 t are necess>y 9 assembl+ ! p>ts :i* make up complete work+ outfits4 ,accurate =mulas & directions = ^! ?+s w save ! amateur tr\ble & exp5se1 s9ce !y indicate ! mat]ials :i* h be5 put to ! te/ ( "t & we> by o!rs :o h _h abundant exp]i5ce along ^! l9es4 ,! amateur w n ne$ a l>ge numb] ( comp\nds1 b su* z are necess>y %\ld be ( ! be/4 ,^? :i* are describ$ 9 ?is *apt] c be reli$ ^u to give work+ results4 ,acid-pro( ,cem5ts ,"o ( ! be/ acid-pro( cem5ts is made by add+ %ellac1 dissolv$ 9 gra9 alcohol1 to r$-lead until x is at ! "r consi/5cy4 ,x c be us$ 9 liquid =m or 9 a putty-l pa/e4 ,! consi/5cy is gov]n$ by ! am\nt ( %ellac add$ to ! r$-lead4 ,! lead %\ld be pulv]iz$ & free f lumps4 ,?is cem5t c be mix$ 9 a small t9 cup or on a piece ( glass1 ) a knife hav+ a ?9 blade4 ,x %\ld be us$ z soon z x is mix$1 s9ce x 8sets0 z quickly z %ellac1 & !n dries f ! outside t[>ds ! middle4 ,9 a week or two x w become dry & h>d l /one4 ,ano!r cem5t1 :i* w also dry z h>d z a /one & w hold soap/one slabs toge!r z if !y 7 ( "o solid piece1 is made ( li?>ge 7yell[ lead7 & glyc]9e4 ,! glyc]9e is add$ to ! pulv]iz$ li?>ge to make a pa/e1 or x c be mix$ & knead$ l ?9 putty4 ,x %\ld be us$ v soon aft] mix+1 z x sets rapidly4 ,h>d ,cem5t ,a m$ium h>d cem5t is made f pla/] ( ,p>is1 six p>ts2 silex1 or f9e s&1 two p>ts2 dextr9e1 two p>ts 7by measure74 ,mix ) wat] until s(t2 !n "w ) a tr[el or knife4 ,s(t ,cem5t ,a good s(t cem5t is made ( pla/] ( ,p>is1 five p>ts2 pulv]iz$ asbe/os1 five p>ts 7by weight74 ,add wat] en\gh to make a s(t pa/e1 & use ) a tr[el or knife4 ,?is is a heat-pro( comp\nd & is commonly kn[n z asbe/os cem5t4 ,v ,h>d ,cem5t ,"o ( ! h>de/ cem5ts t c be made is compos$ ( hydraulic cem5t 7,portl& or ,edison71 five p>ts2 silex1 or :ite s&1 five p>ts 7by measure74 ,mix ) wat] & use l pla/] ) a tr[el or spatula4 ,c>e mu/ be tak5 :5 ! p>ts are comb9$ to see t ! cem5t is free f lumps4 ,^! mu/ be brok5 be=e ! silex1 or s&1 & wat] are add$4 ,!n ! two p>ts %\ld be mix$ toge!r at fir/ & moi/5$ aft]w>ds4 ,! prop] way is to place "s wat] at ! bottom ( a pan2 !n add ! dry mixture by ! h&fuls1 spr9kl+ x ar\nd s t ! wat] c ent] into x )\t =m+ lumps4 ,keep add+ & mix+ until ! mass is at ! "r consi/5cy to "w4 ,all ^! cem5ts are acid-pro(4 ,cl>k's ,comp\nd ,= ext]ior insulation1 :]e ! p>ts are expos$ to ! wea!r1 a sup]ior comp\nd is made up ( m9]al pit*1 t5 p>ts2 silica1 six p>ts2 t>1 "o "p 7all p>ts by weight74 ,?is is call$ ,cl>k's comp\nd1 aft] ! man :o inv5t$ x & us$ x successfully4 ,x is heat$1 ?or\ghly mix$1 & us$ ) a bru% or spatula4 ,batt]y ,fluid ,a depol>iz+ solution = use 9 z9c-c>bon batt]ies l ! ,gr5et is compos$ z foll[s3 ,dissolve "o p\nd ( bi*romate pota% or soda 9 t5 p\nds ( wat] 7by weight74 ,:5 x is ?or\ghly dissolv$ add two & "o-half p\nds ( sulphuric acid1 sl[ly p\r+ x into ! bi*romate solution & /irr+ x ) a glass rod4 ,! addition ( ! acid w heat ! solution4 ,d n use x until x has entirely cool$4 ,glass ,rubb+ ,to rub ! edges ( glass1 su* z ! disks = ,wim%ur/ ma*9es1 obta9 a piece ( h>d s&/one1 su* z is us$ = %>p5+ knives or scy!s4 ,! glass is plac$ on a table s t ! edge ext5ds beyond4 ,oil ( turp5t9e is rubb$ or dropp$ on ! surface ( ! /one1 & ! edge ( ! glass is moi/5$ ) a rag soak$ 9 ! turp5t9e4 ,hold ! glass d[n securely ) "o h&1 & ) ! o!r grasp ! /one & give x a =w>d & backw>d motion1 gr9d+ ! glass along its edge & n crosswise4 ,) c>e & pati5ce a r\gh edge c soon be br\ght to a smoo? "o1 & a s(t1 r\nd$ corn] sub/itut$ = ! h>d1 angul>1 cutt+ edge t makes ! glass a difficult ?+ to h&le4 ,use pl5ty ( lubricant 9 ! =m ( oil ( turp5t9e to make ! "w easy4 ,acetic ,glue ,"o ( ! be/ glues = glass & wood or glass & fibre is made by plac+ "s high-grade glue 7ei!r flake or granulat$7 9 a cup or t9 & cov]+ x ) cold wat]4 ,all[ x to /& sev]al h\rs until ! glue absorbs all ! wat] x w & becomes s(t2 !n p\r ! wat] (f1 & add glacial acetic acid to cov] ! glue4 ,! proportion %\ld be eighte5 p>ts ( glue to two ( acid4 ,heat ! mass until x is r$uc$ to liquid1 /irr+ x until x is ?or\ghly mix$4 ,:5 ready = use x %\ld be p\r$ into a bottle & well cork$ to keep ! air away f x4 ,insulators ,ap>t f glass & porcela91 insulators c be made f non-conduct+ comp\nds1 ! be/ ( :i* is mold$ mica4 ,gr\nd mica or mica du/ is mix$ ) ?ick %ellac until x is 9 a putty-l /ate4 ,x may !n be =c$ into oil$ molds ( any desir$ %ape4 ,hydraulic pressure is employ$ = almo/ e =m ( mold$ mica t is made = comm]cial purposes2 b z a boy _c employ t means to get ! be/ results1 he mu/ use all ! pressure t 8 h&s & a flat bo>d w give4 ,ano!r comp\nd is made f pulv]iz$ asbe/os & %ellac1 ) a small portion ( gr\nd or pulv]iz$ mica add$1 9 ! proportion ( asbe/os1 six p>ts2 mica1 f\r p>ts4 ,%ellac is add$ to make a pa/y mass1 :i* is knead$ into a ?ick putty & =c$ into oil$ molds until x sets4 ,x is !n remov$ & all[$ to dry 9 ! op5 air1 & ! mold us$ = m insulators4 ,non-conductors ,:5 work+ 9 diff]5t mat]ials t seem adapt$ to electrical app>atus1 x is necess>y to "k :e!r !y c be us$ safely or n4 ,(t5 a mat]ial seems to be j ! ?+1 b if x %\ld be a p>tial conductor1 :5 a non-conductor is desir$1 x w\ld be haz>d\s to use x4 ,a li/ ( non-conductors is !re=e valuable to ! amateur4 ,"s ( ! pr9cipal non-conductors1 among ! _m1 are z foll[s3 glass1 porcela91 slate1 m>ble1 h>d /one1 soap/one1 concrete 7dry71 h>d rubb]1 s(t rubb]1 composition fibre1 mica1 asbe/os1 pit*1 t>1 %ellac1 cotton1 silk2 cotton1 silk & wooll5 fabrics1 transite 7dry71 electrobe/us 7dry71 duranoid2 celluloid1 dry wood 7well season$71 pap]1 pi?1 lea!r1 & oil4 ,:ile ?is acc\nt ( =mul & mat]ial might be ext5d$1 ?is is n necess>y inasmu* z ! =mul & practical directions :i* h be5 giv5 w answ] all usual practical requirem5ts4 ,insulat+ ,v>ni% ,!re are sev]al good insulat+ v>ni%es t c be us$ 9 electrical "w1 ! mo/ valuable be+ %ellac dissolv$ 9 alcohol & appli$ ) a bru%4 ,to make good %ellac1 pur*ase ! orange-color$ flake %ellac by ! p\nd f a pa9t-/ore1 place "s ( x 9 a wide-neck$ bottle1 & cov] x ) alcohol2 !n cork ! bottle & let x /& = a few h\rs4 ,%ake ! bottle occasionally until ! %ellac is ?or\ghly dissolv$4 ,x c be ?9n$ by add+ alcohol4 ,always keep ! bottle cork$1 tak+ out only :at is necess>y f "t to "t4 ,ano!r v>ni% c be made by dissolv+ r$ seal+-wax 9 alcohol & add+ a small portion ( %ellac4 ,?is c be appli$ ) a s(t bru%1 & is a good v>ni%4 ,:5 colors are to be appli$ to di/+ui% ! poles1 r$ is us$ = ! positive curr5t-poles & blue or black = ! negative1 if !y are color$ at all4 ,a v good black v>ni% is made by add+ lampblack to %ellac2 ano!r consi/s ( ?ick asphaltum or asphaltum v>ni%4 ,?is is wat]pro(1 & dries h>d1 yet ) an ela/ic f9i%4 ,batt]y ,wax ,= ! upp] edges ( glass cells1 su* z ! ,leclan* or o!r op5-circuit batt]ies1 !re is no?+ sup]ior to hot p>aff9e bru%$ ab\t ! upp] edge to prev5t ! sal-ammoniac or o!r fluids f creep+ up ov] ! top4 ,! p>aff9e c be color$ ) r$-lead1 gre5 du/1 or p[d]s ( v>i\s colors if desir$1 b g5]ally ! p>aff9e is us$ )\t color1 s t x has a fro/$-glass appe>ance :5 x is cool & dry4 ,a black wax = use 9 /opp+ ! tops ( dry cells & coat+ ! tops ( c>bons is compos$ ( p>aff9e1 eight p>ts2 pit*1 "o "p2 lampblack1 "o "p4 ,heat ! mixture & /ir x until ?or\ghly mix$2 !n apply ) a bru%1 or dip ! p>ts into ! w>m fluid4 ,ano!r good black wax is compos$ ( t> & pit* 9 equal p>ts4 ,!y are made into a pa/y mass ) turp5t9e heat$ ov] a /ove1 b n ov] an op5 flame1 because ! +r$i5ts are inflammable4 ,! comp\nd %\ld be l v ?ick molasses1 & c be work$ ) an old table-knife4 ,*apt] ,,xv ,,electric ,,light1 ,,heat1 ,,& ,,p[] ,= ! use ( ! cuts 9 ?is *apt]1 ! ,publi%]s desire to ackn[l$ge ! c\rtesy ( ! ,g5]al ,electric ,company1 ! ,?omson ,electric ,weld+ ,company1 & ! ,coop] ,hewitt ,electric ,company4 ,) ! discov]y ( ! rev]sibility ( ! dynamo1 ! inv5tion ( ! telephone1 & ! improvem5ts 9 ! electric light began ! great mod]n developm5t ( electricity :i* prov$ t m>vell\s ag5t to be a ma/]-workman4 ,_m ( ! ?+s electrical t we ord9>ily ?9k ( z mod]n inv5tions are m]ely mod]n applications ( ph5om5a t 7 discov]$ _m ye>s ago4 ,! pione]s 9 ! sci5ce ( dynamic electricity p]=m$ _! exp]im5ts ) ! electric light1 electro-magnets1 etc41 by us+ galvanic batt]ies4 ,b = practical purposes ! consum+ ( z9c & *emicals 9 su* batt]ies 0 too exp5sive a way to g5]ate electricity1 & prev5t$ any comm]cial use ( ! results ( _! exp]im5ts until *eap] electricity c\ld be _h4 ,! ,"w ( ! ,dynamo ,! inv5tion ( ! dynamo1 ) :i* we obta9 electricity f me*anical p[]1 *ang$ all t4 ,in/ead ( consum+ z9c 9 prim>y batt]ies1 m5 c\ld obta9 x by burn+ coal1 :i* is mu* *eap]1 "u ! boil] ( a /eam-eng9e us$ to drive ! dynamo4 ,?us x is t mod]n electricity comes f me*anical p[]4 ,x is really ! en]gy ( a /eam-eng9e or a wat]-:eel1 or "s o!r 8prime mov]10 work+ ?r\gh ! m$ium ( electricity1 t is transmitt$ to a di/ance & di/ribut$ ov] wires4 ,! electricity may !n be transmut$ into light1 heat1 or *emical en]gy z ! case may be1 to light our electric lamps1 develop ! int5se heat ( ! electric furnace1 & *>ge /orage-batt]ies4 ,moreov]1 "s "t aft] ! inv5tion ( ! dynamo x 0 f\nd t ! me*anical p[] put into "o ( ^! ma*9es c\ld be transmitt$ electrically & reproduc$ z me*anical p[]4 ,9 o!r words1 a dynamo c\ld be made to revolve & give out p[]1 z a motor1 by supply+ x ) curr5t f ano!r dynamo4 ,?is %[$ ! way to transmute electricity back aga9 into me*anical p[]1 to run our electric c>s & tra9s1 & all k9ds ( ma*9]y 9 our factories & else:]e4 ,n[adays ! dynamo is us$ to g5]ate ne>ly all ! electricity t we ne$4 ,ev5 9 su* comp>atively old electrical applications z electro-plat+ & ! telegraph & telephone1 prim>y batt]ies are be+ supplant$ by motor dynamos1 :i* we %all le>n ab\t lat]4 ,x is f ! inv5tion ( ! dynamo & ! discov]y t x 0 rev]sible t we date ! beg9n+ ( :at are kn[n z heavy electrical eng9e]+ applications1 includ+ electric light1 heat1 & p[]4 ,9 ?is clos+ *apt] x is purpos$ to le>n a little ab\t ^! applications1 & 9 s do+ to summ>ize briefly ! ?+s t we h already /udi$4 ,! ,electric ,light ,9 ! *apt] on ,electrical ,resi/ance we le>n$ t an electric curr5t always enc\nt]s a resi/ance 9 pass+ ?r\gh a conductor1 & t :5 ! curr5t is /rong en\gh ! conductor is heat$ up4 ,! electric light is produc$ by ! heat+ ( a conductor ( "o k9d or ano!r to inc&esc5ce by ! electrical friction ( ! curr5t pass+ ?r\gh x4 ,! fir/ electric light 0 made by ,sir ,humphry ,davy ov] a hundr$ ye>s ago4 ,he discov]$ t :5 a curr5t f a great _m cells ( batt]y 0 int]rupt$ ! sp>k did n simply appe> = an in/ant & !n g out1 z x does :5 only a few cells are us$1 b rema9$ play+ betwe5 ! t]m9als ( ! circuit4 ,he f\nd by exp]im5t t if pieces ( c>bon are us$ z ! t]m9als--or 8electrodes10 z !y are call$--! electricity passes betwe5 !m 9 an int5sely hot flame1 or 8arc40 ,! latt]1 :i* is due to ! electrical resi/ance ( ! vapor ( c>bon1 heats up ! c>bon-po9ts s t !y give a brilliant :ite light4 ,illu/ration3 ,fig4 #a ,illu/ration3 ,fig4 #b ,be=e ! dynamo came into use1 ! electric light 0 r>ely se51 except z a philosophical exp]im5t2 b z soon z *eap electricity became available1 comm]cial electric arc-lamps 7 made by _m inv5tors & h be5 cont9ually improv$4 ,fig4 #a %[s "o =m ( mod]n arc-lamp1 ) its case remov$ to %[ ! int]ior me*anism4 ,9 mo/ arc-lamps ! lamp itself consi/s ( a pair ( c>bon or o!r electrodes 9 ! =m ( long rods arrang$ v]tically1 ) _! tips normally 9 contact4 ,:5 ! curr5t is turn$ on1 ! me*anism lifts ! upp] electrode away f ! l[] "o4 ,! int]ruption ( ! circuit ?us caus$ 8/rikes ! arc0 betwe5 ! tips1 & ! me*anism keeps ! arc-di/ance un*ang$ z ! c>bons burn away4 ,"s arc-lamps are made to burn on cont9u\s-curr5t1 & o!rs on alt]nat+-curr5t circuits4 ,:5 cont9u\s curr5t is us$1 ! upp] 7or positive7 c>bon burns away ab\t twice z fa/ z ! l[] "o1 =m+ a cup1 or 8crat]10 f :i* mo/ ( ! light comes4 ,uses ( ! ,arc-,light ,! fir/ comm]cial use ( ! arc-light on a l>ge scale 0 = /reet-light+1 to replace ! old-fa%ion$ gas-lamps4 ,b ano!r important use is 9 se>*-lights1 9 :i* ! arc-lamp is fitt$ ) a p[]ful reflector = ?r[+ a v bright light to a di/ance4 ,fig4 #b is a view ( a se>*-light arrang$ to g on top ( a %ip's pilot-h\se4 ,9 w>-"t ! %ips c>ry se>*-lights to help !m f9d ! enemy's %ips & repel attack2 & !y are us$ 9 ! army also1 by hav+ a portable dynamo & eng9e drawn by horses4 ,! arc is also employ$ 9 projectors = lecture-rooms1 & sometimes = ! headlights ( /eam & electric locomotives & int]urban electric c>s4 ,inc&esc5t & ,o!r ,lamps ,! arc-lamp came into wide use = light+ l>ge spaces l /reets1 /ores1 & public halls1 b 0 f\nd to be too int5se = light+ small] places l private h\ses4 ,aft] _m exp]im5ts1 ,edison succe$$ 9 subdivid+ ! electric light into ! small pe>-%ap$ 8inc&esc5t0 lamps t we n[ see ev]y:]e4 ,9 ?is k9d ( electric lamp ! light comes f a ?9 8filam5t0 ( c>bon1 conta9$ 9 a glass globe f :i* all air has be5 remov$4 ,s9ce !re is no oxyg5 to support combu/ion1 ! filam5t may be heat$ :ite-hot by ! curr5t )\t be+ consum$4 ,illu/ration3 ,fig4 #c ,9 c]ta9 o!r =ms ( inc&esc5t lamps t are j com+ into use1 ! filam5ts are made ( r>e metals--osmium1 tantalum1 etc4--t w /& a high temp]ature )\t melt+4 ,! ,n]n/ lamp has a filam5t consi/+ ( a mixture ( c]ta9 mat]ials t has to be heat$ be=e x w conduct electricity4 ,!n !re are ! s-call$ 8vapor0 lamps1 consi/+ ( a glass tube full ( conduct+ metallic vapor :i* gives out light :5 a curr5t is pass$ ?r\gh x4 ,! be/-kn[n =m is ! ,coop] ,hewitt m]cury vapor-lamp %[n 9 ,fig4 #c1 :i* gives a peculi> gre5i% light4 ,f ! po9t ( view ( effici5cy1 ! electric light1 wond]ful z x is1 leaves mu* to be desir$4 ,! light always comes f a hot resi/ance2 & :e!r ?is resi/ance is a mass ( conduct+ vapor1 z 9 ! arc & vapor lamps1 or a solid conduct+ filam5t1 z 9 ! s-call$ 8inc&esc5t0 lamps1 mu* m heat ?an light is produc$4 ,a ne$$ improvem5t1 !re=e1 is 9 ! direction ( obta9+ a great] p]c5tage ( light = a giv5 am\nt ( electrical en]gy4 ,electric ,heat ,! g5]ation ( heat 9 electrical devices usually means wa/$ en]gy--sometimes a v s]i\s wa/e1 z we h j se54 ,!re are c]ta9 k9ds ( electrical app>atus1 h[ev]1 t are design$ to trans=m all ( ! electrical en]gy deliv]$ to !m into heat1 = v>i\s indu/rial & h\sehold purposes4 ,illu/ration3 ,fig4 #d ,electric ,furnaces ,by f> ! mo/ important application ( electric heat1 z su*1 is 9 electric furnaces1 by means ( :i* we atta9 ! highe/ temp]atures kn[n to man4 ,! electric furnace consi/s ( a *amb] ( 8refractory0 mat]ial1 conta9+ ! sub/ances to be act$ ^u by ! heat1 ) a pair ( big c>bon electrodes ?ru/ into ! c5tre1 z %[n 9 ,fig4 #d1 :i* is a picture ( ,moissan's electric furnace = ! di/illation ( metals1 & suppli$ ) heavy cont9u\s or alt]nat+ curr5ts4 ,! app>atus is !re=e a sort ( gigantic electric arc-lamp1 s enclos$ t ! :ole ( ! int5se heat ( ! arc is conf9$ & conc5trat$ on ! smelt+ or o!r "w4 ,9 _m places :]e *eap electric p[] is to be _h--z 9 ! vic9ity ( ! great ,niag>a ,falls p[]-plants--electric furnaces are employ$ 9 :at are kn[n z electrometallurgical & electro*emical manufactur+ processes4 ,by _! aid _m metals & o!r sub/ances t 7 =m]ly sci5tific curiosities1 or entirely unkn[n1 are produc$ comm]cially2 su* z alum9um1 c]ta9 r>e metals1 & calcium c>bide1 f :i* t wond]ful illum9ant1 acetyl5e-gas1 is obta9$4 ,weld+ ,metals ,ano!r useful application ( electric heat is 9 ! weld+ ( metals4 ,in/ead ( heat+ ! pieces to be weld$ 9 a =ge1 _! ends are simply butt$ toge!r & ! electricity--g5]ally f an alt]nat+-curr5t trans=m]--turn$ on4 ,! heat develop$ by ! 8contact resi/ance0 betwe5 ! pieces quickly s(t5s ! metal s t ! pieces may be =c$ toge!r1 =m+ a p]fect weld 9 a few m9utes )\t any hamm]+4 ,fig4 #e is a view ( "o =m ( electric weld+-ma*9e 9 :i* ?is is accompli%$4 ,! electric process c weld c]ta9 metals t _c be jo9$ securely by ord9>y weld+ me?ods1 & is us$ 9 sev]al special arts4 ,weld+ is also p]=m$ by ! heat ( a special electric arc-lamp1 :i* a workman holds 9 8 h& l a bl[-pipe or tor*4 ,?is process is especially useful 9 jo9+ ! edges ( %eet-/eel1 9 mak+ tanks = electric 8trans=m]s10 etc4 ,! workm5 h to we> smok$ glasses 9 ord] to protect _! eyes f ! int5se gl>e ( ! arc4 ,illu/ration3 ,fig4 #e ,electric ,c>-heat]s ,p]haps ! simple/ & be/-kn[n application ( electric heat is ! electric c>-heat]1 consi/+ ( coils ( high-resi/ance wire--su* z iron or ,g]man-silv] wire--m\nt$ on an insulat+1 non-combu/ible frame :i* is plac$ "u ! seats ( ! c>4 ,"p ( ! curr5t f ! trolley wire or ?ird rail passes ?r\gh ! resi/ance-coils1 heat+ !m up & !reby w>m+ ! air 9 ! c>4 ,h\sehold ,uses ,n[adays electric heat is be+ m & m widely utiliz$ 9 :at are kn[n z h\sehold electric heat+-appliances4 ,"o ( ! mo/ useful ( ^! is ! electric flat-iron1 %[n 9 ,fig4 #f4 ,?is flat-iron is design$ to d away ) ! use ( a hot /ove ( any k9d1 & is int]nally heat$ by means ( a resi/ance-coil ( peculi> %ape plac$ 9 ! bottom ( ! iron close aga9/ its work+ face4 ,! iron is connect$ to an electric-light socket by means ( an atta*+ plug on ! end ( a long1 flexible cord4 ,x takes only a few m9utes to get hot1 & its use saves mu* "t & labor4 ,! li/ ( special heat+-appliances t are n[ made includes curl+-iron heat]s2 heat+-pads1 = tak+ ! place ( hot-wat] bags 9 ! sick-room2 cig>-light]s1 9 :i* a little grid 8resi/ance0 is made inc&esc5t by press+ a button2 foot-w>m]s2 & radiators to dry wet %oes or skirts on ra9y days4 ,= indu/rial use !re are glue-pots1 = bookb9d]s & patt]n-mak]s2 l>ge flat-irons1 = tailor-%ops & laundries2 & electric ov5s1 = dry+ c]ta9 p>ts ( electrical ma*9es & = cook+ v>i\s k9ds ( 8prep>$ foods40 ,_m electric cook+-ut5sils are made = ! h\sehold1 su* z c(fee-p]colators1 egg-boil]s1 ov5s1 disk /oves1 etc4 ,ea* "o is equipp$ ) a resi/ance-coil l t 9 ! electric flat-iron j describ$1 s t x conta9s its own s\rce ( heat1 :i* is "u p]fect control by means ( a swit*4 ,an 8electric kit*50 consi/s ( a numb] ( ^! ut5sils1 wir$ to a conv5i5t table or /&1 z %[n 9 ,fig4 #g4 ,illu/ration3 ,fig4 #f ,illu/ration3 ,fig4 #g ,electric ,p[] ,we h se5 t ! mod]n way to g5]ate electricity is f me*anical en]gy appli$ ?r\gh a dynamo1 & t ! 8electric p[]0 ?us g5]at$ may be transmitt$ ov] wires to a di/ance & !re trans=m$ into o!r =ms ( en]gy1 su* z light1 heat1 & *emical en]gy1 or reproduc$ aga9 z me*anical en]gy4 ,! la/ m5tion$ ( ^! trans=mations is ! mo/ important ( !m all1 because x is ! "o t means ! mo/ = ! advancem5t ( civilization4 ,be=e ! inv5tion ( ! dynamo & ! discov]y t x 0 rev]sible1 me*anical p[] c\ld be employ$ only 9 ! place :]e x 0 g5]at$1 s t its use 0 re/rict$2 :]eas n[adays ! field ( p[] is broad5$ & its co/ r$uc$ by electrical transmission & di/ribution4 ,9 ! *apt] on ,dynamos & ,motors we le>n$ h[ to make & use ^? ma*9es4 ,let u review1 v briefly1 j :at happ5s 9 ! d\ble trans=mation--( me*anical en]gy into electricity & !n back aga9 at ! end ( a l9e ( wires--t we call electric-p[] transmission4 ,9 ! dynamo1 ! p[] ( ! wat]-:eel1 or :atev] o!r prime mov] is us$1 is ex]t$ 9 g5]at+ electricity by =c+ ! electric conductors ( ! ma*9e ?r\gh a magnetic field4 ,! electricity is l$ away to a di/ance--a hundr$ miles1 p]haps--by wires & all[$ to ent] ano!r ma*9e simil> to ! dynamo1 b op]at+ z a motor4 ,"h ! fir/ process is rev]s$3 ! electricity pass+ ?r\gh ! conductors ( ! motor reacts ^u its magnetic field1 caus+ ! ma*9e to revolve & ?us g5]at+ me*anical p[] aga94 ,! l9e-wires c>ry ! p[] j z positively z ?\gh a long %aft ran f ! prime mov] to ! receiv+ end ( ! l9e1 & mu* m economically4 ,! action t goes on is simil> to ! op]ation ( ! telephone--:i* is inde$ a special case ( electric-p[] transmission--z already expla9$ 9 a =m] *apt]3 ! s\nd ( ! voice be+ trans=m$1 at ! telephone-transmitt]1 into electrical en]gy 9 ! =m ( alt]nat+ curr5ts1 !n c>ri$ z su* ov] ! l9e & f9ally reproduc$ z s\nd aga9 at ! receiv]4 ,p[] f ,wat]-:eels 8,hydro-electric0 transmissions--i4 e41 electric transmissions ( p[] f a wat]-:eel z prime mov]--are ! mo/ important because !y br+ into use *eap wat]-p[] t =m]ly ran to wa/e4 ,!re are _m hydro-electric transmissions 9 ?is c\ntry1 ,mexico1 & ,canada1 "s ( !m utiliz+ ! p[] ( wat]falls or rapids locat$ 9 m\nta9\s & inaccessible p>ts4 ,! alt]nat+ curr5t is ne>ly always us$ because by x m5 c mu* m easily & safely g5]ate1 transmit1 & receive ! high voltages t h to be us$ ?an by ! cont9u\s curr5t4 ,! ma*9]y at ! 8ma9 g5]at+ /ation0 consi/s ( big alt]nat+-curr5t dynamos1 :i* sometimes h v]tical %afts in/ead ( horizontal ones1 s t !y may be driv5 directly by turb9es4 ,! curr5t is g5]at$ at a mod]ate pot5tial1 :i* is !n 8/epp$-up10 by 8/atic trans=m]s10 to ! comp>atively high-l9e voltage t is requir$ 9 long-di/ance transmissions4 ,illu/ration3 ,fig4 #h ,trans=m]s ,fig4 #h is a view ( a v l>ge trans=m] ( ov] #bejj electrical horse-p[] capacity4 ,9 ! picture ! conta9+-tank is repres5t$ z transp>5t1 s z to %[ ! trans=m] prop] inside4 ,! latt] is really a special k9d ( induction-coil1 ) prim>y & second>y w9d+s1 & a core1 weigh+ _m tons1 built up ( ?9 %eets ( /eel4 ,9 ?is k9d ( trans=m]1 ! tank is fill$ ) oil1 to keep ! trans=m] cool 9 op]ation1 & to help insulate x aga9/ ! high pot5tial to :i* x is subject$4 ,at ! receiv+ end1 or 8sub-/ation10 ! high-voltage electric p[] ent]s a set ( 8/ep-d[n0 trans=m]s1 f :i* x is deliv]$ aga91 at mod]ate pot5tial1 to ! motors4 ,sometimes p[] is di/ribut$ f a s+le great g5]at+ /ation to sev]al sub-/ations4 ,9 ! ,necaxa transmission1 9 ,mexico1 ov] #ce1jjj horse-p[] is tak5 f a wat]fall 9 ! m\nta9s & transmitt$ at #fj1jjj volts pot5tial to ,mexico ,city1 #ajj miles away1 & to ! m9+ t[n ( ,el ,oro1 sev5ty-f\r miles f>!r on4 ,sev]al k9ds ( motors are us$ at ! receiv+ end ( electric-p[] transmission-l9es1 accord+ to ! "w t !y are call$ ^u to d4 ,= 8/ation>y0 "w1 l driv+ ! ma*9es 9 mills & factories1 two pr9cipal k9ds ( alt]nat+-curr5t motors are employ$--syn*ron\s & induction motors4 ,! =m] are built j l alt]nat+-curr5t dynamos1 & :5 !y are runn+ !y keep 89 /ep0 ) ! dynamo at ! o!r end ( ! l9e2 i4 e41 ! motion ( _! field w9d+s relatively to _! armatures keeps exact pace ) ! same motion at ! dynamo1 j z ?\gh a long %aft ran f "o ma*9e to ! o!r in/ead ( ! electric wires ( ! transmission-l9e4 ,a motor ( ?is type1 at "w driv+ an air-compressor1 is %[n 9 ,fig4 #i4 ,! induction-motor is really a sort ( trans=m]1 ! prim>y w9d+ ( :i* is ! fix$ "p1 or field1 & ! second>y w9d+ ! rotat+ armature4 ,x does n keep 9 /ep ) ! dynamo1 l ! syn*ron\s motor1 b adapts its spe$ to ! 8load10 or am\nt ( "w t x is call$ ^u to d1 l a cont9u\s-curr5t motor4 ,illu/ration3 ,fig4 #i ,rot>y ,conv]t]s ,sometimes alt]nat+-curr5t electric p[] is trans=m$ at ! sub-/ation into cont9u\s-curr5t p[]4 ,?is is done by a special k9d ( trans=m] call$ a 8rot>y conv]t]40 ,! /atic trans=m]s ( :i* we h j be5 speak+ are built1 l ord9>y r$uction-coils1 ) no mov+ p>ts1 & op]ate by tak+ 9 alt]nat+ curr5ts at a giv5 pot5tial & giv+ out alt]nat+ curr5ts at a diff]5t pot5tial1 high] or l[] z ! case may be4 ,! rot>y conv]t]1 h[ev]1 is built some?+ l a dynamo1 ) a /ation>y field & a revolv+ armature1 & ord9>ily op]ates by receiv+ an alt]nat+ curr5t at a giv5 pot5tial & deliv]+ a cont9u\s curr5t ( ! same or a diff]5t pot5tial4 ,?is k9d ( trans=mation is employ$ :]ev] x is desir$ to obta9 any l>ge am\nt ( cont9u\s curr5t f an alt]nat+-curr5t transmission-l9e2 & especially to obta9 8#ejj-volt cont9u\s curr5t0 = op]at+ /reet & int]urban electric railways1 z we %all see "u ! next head+4 ,fig4 #aj %[s "o =m ( rot>y conv]t] built = supply+ cont9u\s curr5t = trolley s]vice4 ,illu/ration3 ,fig4 #aj ,(t5times ! sub-/ation ( a transmission sy/em conta9s bo? /atic trans=m]s & rot>y conv]t]s1 to supply bo? alt]nat+ curr5t & cont9u\s curr5t f ! same high-voltage alt]nat+-curr5t l9e4 ,:5 ! cont9u\s curr5t has to be trans=m$ f "o voltage to ano!r1 a 8motor dynamo0 is us$1 consi/+ ( an electric motor driv+ a dynamo on a common %aft4 ,"o ( ! mo/ int]e/+ features ( electric-p[] transmission is ! c>e t is tak5 to avoid ! t]rible dang] f ! high pot5tials1 & at ! same "t prev5t loss ( p[] on ! way4 ,! electricity 9 ! ma*9]y & 9 ! l9e-wires t ext5d across ! c\ntry is v]itable lightn+1 & has to be c>efully gu>d$ f do+ any damage or escap+4 ,to prev5t leakage1 ! insulation ( all ( ! /ation ma*9]y & app>atus is made extra good1 ) 8high dielectric /r5g?10 s t x w n be punctur$ by ! high voltage2 & ! l9e-insulators are made v l>ge1 & electrically & me*anically /rong--q unlike ! ord9>y-siz$ glass or porcela9 insulators t are employ$ = telegraph & telephone l9es4 ,ea* insulator be=e be+ put up is te/$ "u a 8breakd[n voltage0 mu* high] ?an x is to /& 9 actual s]vice4 ,oil-swit*es ,! swit*+ ( high-voltage electric p[] is a knotty problem4 ,! circuit _c be int]rupt$ by 8air-break0 swit*es1 su* z are us$ 9 ord9>y electric-light /ations1 = any attempt to d s w\ld result 9 a de/ructive arc _m feet long1 t c\ld n be ext+ui%$4 ,!re=e 8oil-swit*es0 are always us$ to control ! l9e-circuits at ! ma9 g5]at+ /ation & ! sub-/ations4 ,9 ^! oil-swit*es--:i* are design$ to be op]at$ f a di/ance1 by h&-lev]s1 or sometimes by electric motors--! circuit is made & brok5 "u ! surface ( oil1 :i* prev5ts ! =mation ( an arc4 ,moreov]1 ! swit*bo>d att5dant does n h to come any:]e ne> ! deadly high-voltage wires1 b c make ! necess>y connections at a safe di/ance4 ,electric ,traction ,! use ( ! electric motor to propel vehicles ( all k9ds is call$ electric traction4 ,x is1 ( c\rse1 a bran* ( electric p[]1 :i* we h j be5 consid]+2 & x is 9 _m respects ! mo/ important bran*4 ,! weal? ( a c\ntry is l>gely built up & ma9ta9$ by its facilities = transportation1 su* z its canals1 highways1 railroads1 & /reet & int]urban c>-l9es4 ,9 ?is field electric p[] is play+ a mo/ important "p1 al?\gh x 0 n _m ye>s ago t ! fir/ exp]im5tal electric c>s 7 put 9 to replace horses on ! /reet-railways ( our cities4 ,! *ange 0 f\nd to be s successful t ! field ( ! trolley-c> 0 wid5$ & ext5d$ v rapidly1 until n[ we h our great suburban & int]urban electric railways1 ) c>s almo/ or q z big z ^? on ! /eam-railroads & runn+ at ev5 high] spe$s4 ,dur+ ! la/ few ye>s1 also1 ! sph]e ( ! /eam-railroad itself has be5 invad$ by electricity1 by ! con/ruction ( p[]ful electric locomotives to draw pass5g] & freight tra9s4 ,! ,trolley-c> ,let u consid] j :at x is t makes a trolley-c> g4 ,s9ce electric p[] is only me*anical en]gy 9 ano!r =m1 we "k t ! motionless copp] trolley-wire1 susp5d$ ov] ! track 9 our /reets1 is ! means ( propell+ ! c> j z truly--?\gh 9 a diff]5t way--z if x 7 a mov+ /eel cable to :i* ! c> 0 atta*$4 ,we mu/ keep 9 m9d ! fact t ! electricity is n itself ! s\rce ( p[]1 b only ! m$ium ( transmission4 ,! eng9e 9 ! p[]-h\se1 by turn+ a dynamo !re1 ma9ta9s a con/ant electric pressure1 or 8con/ant pot5tial10 z x is t]m$1 9 ! trolley-wire4 ,?is pressure ( electricity =ces ! p[] ?r\gh ! motors ( ! c> z soon z ! motorman makes ! connection to !m by turn+ ! h&le ( 8 8controll]40 ,illu/ration3 ,fig4 #aa ,! ,cont9u\s-curr5t ,motor ,fig4 #aa is a view ( "o =m ( cont9u\s-curr5t motor4 ,!re is n mu* ( ! motor itself to be se51 because x is entirely enclos$ 9 a ca/-iron case4 ,! %aft ( ! motor has a small 8spur ge>0 fix$ on "o end1 driv+ a ge>-:eel :i* is fix$ on ! c> axle4 ,by ?is arrangem5t m ?an "o revolution ( ! motor armature is requir$ to make "o revolution ( ! c>-:eel1 :i* multiplies ! =ce ex]t$ 9 turn+ ! :eel4 ,illu/ration3 ,fig4 #ab ,! ,controll] ,fig4 #ab is a view ( a type ( controll] t is us$ on ! plat=m ( trolley-c>s4 ,! cov] is remov$ to %[ ! contacts1 inside1 by :i* ! electric p[] is turn$ on gradually by ! controll] h&le4 ,! tra9s ( electric c>s t run on ! elevat$ /ructures & 9 ! subways ( our l>ge cities are suppli$ ) p[] f a 8?ird rail0 plac$ by ! side ( ! track1 on insulat+ supports1 & ! motors on all ! c>s are controll$ f a s+le 8ma/]-controll]0 on ! front plat=m ( ! =w>d c>4 ,?is sy/em ( control1 kn[n z ! 8multiple-unit0 sy/em1 gives electric tra9s sev]al advantages ov] ! old k9d1 drawn by /eam-locomotives2 su* z !y us$ to h on ! ,new ,york elevat$ roads1 = example4 ,= "o ?+1 ! tra9 c be />t$ mu* m quickly1 s9ce all ! motors beg9 to turn ! c>-:eels at ! same in/ant4 ,!n aga91 ! sy/em enables a long tra9 ( c>s to be controll$ z easily z a s+le c>1 & bett] 8traction0 betwe5 :eels & track is obta9$4 ,electric ,locomotives ,sev]al ( ! great /eam-railroads are n[ adopt+ ! electric locomotive to draw _! tra9s4 ,fig4 #ac is a view ( "o ( ! great cont9u\s curr5t electric locomotives t are us$ by ! ,new ,york ,c5tral ,railroad to h&le _m ( its pass5g]-tra9s 9 & out ( ! ,gr& ,c5tral ,/ation1 9 ,new ,york city4 ,! motors ( ?is p[]ful electric eng9e1 unlike ^? ( trolley-c>s1 are 8ge>less02 t is1 _! armatures are fix$ directly on ! locomotive axles s t !y revolve at ! same spe$ z ! driv+-:eels4 ,illu/ration3 ,fig4 #ac ,all ( ! railway motors consid]$ ?us f> h be5 ( ! cont9u\s-curr5t type1 al?\gh ! curr5t to op]ate !m is (t5 obta9$ f alt]nat+ curr5t transmission-sy/ems1 ?r\gh rot>y conv]t]s1 z describ$ above4 ,! alt]nat+ curr5t is also beg9n+ to be employ$ to drive c>s & tra9s4 ,"o type ( alt]nat+ curr5t railway motor1 design$ = 8s+le-phase0 op]ation1 is 9 use on sev]al int]urban sy/ems 9 ?is c\ntry1 runn+ on high-voltage alt]nat+ curr5t mo/ ( ! "t1 b on cont9u\s curr5t :5 )9 ! city limits4 ,o!r ,=ms ( ,electric ,traction ,electric traction also includes electric automobiles1 suppli$ by /orage-batt]ies2 a sl[-spe$ electric locomotive = draw+ canal-boats1 & call$ 8! electric mule02 & an +5i\s gasol5e-electric outfit = driv+ c>s by electric motors )\t any trolley1 ?ird rail1 or /orage-batt]y4 ,! la/-m5tion$ arrangem5t consi/s ( a set ( electric c>-motors m\nt$ on ! trucks 9 ! usual way1 b suppli$ ) curr5t by a dynamo m\nt$ on ! c> itself & driv5 by a gasol5e-eng9e4 ,?us ! c> c>ries its own p[]-/ation ab\t ) x1 & is indep5d5t ( any outside s\rce ( electricity4 99 99 99 99 99 ,! old al*emi/s s\ght to transmute matt] f "o =m to ano!r2 & especially lead & o!r 8base metals0 into gold1 9 ord] t !y might gr[ ri* by conc5trat+ ! preci\s metal 9 _! own selfi% h&s4 ,! mod]n miracle t electricity works = u1 ! transmutation ( en]gy1 is a high] & broad] ?+1 because x multiplies & di/ributes ! _w's good ?+s4 ,,app5dix ,a ,,diction>y ,,( ,,electrical ,,t]ms ,,& ,,phrases ,ev]ybody is int]e/$ 9 electricity1 b ! ord9>y read]1 & p>ticul>ly ! boy :o attempts to use ?is manual intellig5tly1 w come across _m te*nical words & t]ms t require explanation4 ,x w\ld be impossible to incorporate all ne$ful def9itions 9 ! text prop]1 & ! read] is !re=e ref]r$ to ! te*nical diction>y on ! succe$+ pages4 ,c>e has be5 tak5 9 its compilation to make ! def9itions complete1 simple1 & concise4 ,"s ( ! m advanc$ te*nical t]ms h be5 purposely omitt$ z n necess>y 9 a book deal+ ) elem5t>y pr9ciples4 ,! /ud5t 9 ! high] bran*es ( ! sci5ce w consult1 ( c\rse1 ! m advanc$ text-books4 ,b = our practical purposes ?is elem5t>y diction>y %\ld answ] e requirem5t4 ,to read x ov] is an education 9 itself1 & ! "y exp]im5t] 9 electrical sci5ce %\ld always ref] to x :5 he comes across a ^w or phrase t he does n fully und]/&4 ,a ,a4 ,an abbreviation = ! ^w anode4 ,absolute4 ,complete by itself4 ,9 quantities x ref]s to fix$ units4 ,a galvanomet] gives absolute read+s if x is graduat$ to read direct amp]es or volts4 ,an absolute vacuum is "o 9 :i* all residual gases are exhau/$2 an absolute void is ! !oretical consequ5t4 ,! absolute unit ( curr5t is measur$ 9 "o1 two1 ?ree1 or m amp]es or volts4 ,a-,c4 ,an abbreviation express+ alt]nat+ curr5t4 ,accel]ation4 ,! rate ( *ange 9 velocity4 ,! increase or decrease ( motion :5 act$ ^u by ! electric curr5t4 ,accumulator4 ,a t]m appli$ to a second>y batt]y1 commonly call$ a /orage-batt]y4 ,accumulator1 ,electro/atic4 7,see ,electro/atic ,accumulator47 ,accumulator1 ,/orage4 ,a /orage-batt]y4 ,acid4 ,a comp\nd ( hydrog5 capable ( unit+ ) a base to =m salts4 ,s\r1 resembl+ v9eg>4 ,a %>p1 bit+ fluid4 ,acidomet]4 ,a hydromet] us$ to det]m9e ! gravity ( acids4 ,x is employ$ *iefly 9 runn+ /orage-batt]ies to det]m9e :5 ! *>ge is complete4 ,adapt]4 ,a screw-c\pl+ to engage ) diff]5t size screws on ei!r end1 & us$ *iefly to connect inc&esc5t lamps to gas-fixtures4 ,adh]5ce4 ,! attraction betwe5 surfaces ( iron due to electro-magnetic action4 ,! t]m is us$ 9 connection ) electric brakes--electro-magnetic adh]5ce4 ,adju/m5t4 ,any *ange 9 an app>atus r5d]+ x m effici5t & correct 9 its "w4 ,a]ial ,conductor4 ,a wire or electric conductor c>ri$ ov] h\setops or poles1 or o!rwise susp5d$ 9 ! air1 z di/+ui%$ f und]gr\nd or subm>9e conductors4 ,aff9ity4 ,! attraction ( atoms & molecules = ea* o!r1 due to *emical or electrical action4 ,air-cond5s]4 ,a /atic cond5s] ^: dielectric is air4 ,air-l9e ,wire4 ,9 telegraphy t portion ( ! l9e-wire :i* is /rung on poles & c>ri$ ?r\gh ! air4 ,al>m1 ,burgl>4 ,a sy/em ( circuits ) an al>m-bell1 ! wires ( :i* ext5d ov] a h\se or build+1 connect+ ! w9d[s & doors ) ! annunciator4 ,al>m1 ,electric4 ,an appliance = call+ att5tion1 g5]ally ?r\gh ! r++ ( a bell or ! op]at+ ( a horn4 ,al>m1 ,fire & ,heat4 ,an expansion app>atus t automatically closes a circuit & r+s a bell4 ,alive1 or 8,live40 ,a t]m appli$ to a wire or circuit t is *>g$ ) electricity4 ,a 8live0 wire4 ,active circuits or wires4 ,alloy4 ,any mixture ( two or m metals mak+ a sci5tific comp\nd4 ,= example3 copp] & z9c to =m brass2 copp]1 t91 & z9c to =m bronze2 copp]1 nickel1 & z9c to =m ,g]man-silv]4 ,alt]nat+ ,curr5t4 7,see ,curr5t1 ,alt]nat+47 ,alt]nat+ ,curr5t-p[]4 ,electrical di/ribution employ+ ! alt]nat+ curr5t f dynamos or conv]t]s4 ,alt]nation4 ,a *ange 9 ! direction ( a curr5t2 to & fro4 ,alt]nations may take place ) a frequ5cy rang+ f #ejj to #aj1jjj or m vibrations p] second4 ,alt]nator4 ,an electric g5]ator-dynamo supply+ an alt]nat+ curr5t4 ,amalgam4 ,a comb9ation ( m]cury ) any o!r metal4 ,amalgamation4 ,! application ( m]cury to a metal1 ! surface ( :i* has be5 cleans$ ) acid4 ,m]cury w adh]e to all metals1 except iron & /eel1 & p>ticul>ly to z9c1 :i* is treat$ ) m]cury to ret>d ! corrosive action ( acid on its surface4 ,amb]4 ,a fossil res91 valuable only 9 frictional electric exp]im5ts4 ,mo/ ( x is ga!r$ on ! %ores ( ! ,baltic ,sea betwe5 ,knigsb]g & ,memel4 ,x is also f\nd 9 small quantities at ,gay ,head1 ,massa*usetts1 & 9 ! ,new ,j]sey gre5 s&4 ,:5 rubb$ ) a clo? x becomes excit$ ) negative electricity4 ,ammet]4 ,! comm]cial "n = an amp]e-met]4 ,an in/rum5t design$ to %[1 by direct read+1 ! numb] ( amp]es ( curr5t :i* are pass+ ?r\gh a circuit4 ,amp]e4 ,! practical unit ( electric curr5t /r5g?4 ,x is ! measure ( ! curr5t produc$ by an electro-motive =ce ( "o volt ?r\gh a resi/ance ( "o ohm4 ,amp]e-curr5ts4 ,! curr5ts !oretically assum$ to be ! cause ( magnetism4 ,amp]e-h\r4 ,! quantity ( electricity pass$ by a curr5t ( "o amp]e 9 "o h\r4 ,x is us$ by electric light & p[] companies z ! unit ( en]gy suppli$ by !m1 & on :i* !y base _! reckon+ = measur+ ! *>ges = curr5t consum$4 ,amp]e-r+4 ,a conductor =m+ a r+ or circle4 ,us$ 9 electric balances = measur+ curr5t4 ,animal ,electricity4 ,a =m ( electricity ( high t5sion g5]at$ 9 c]ta9 animal sy/ems--! ,torp$o1 ,gymnotus1 & ,clurus4 ,! %ocks giv5 by ^! fi%1 & p>ticul>ly ! electric eel1 are (t5 v sev]e4 ,anneal+4 ,! process ( s(t5+ yell[ metals by heat+ !m to a *]ry r$ness1 !n all[+ !m to cool gradually 9 ! air4 ,electric anneal+ is done by pass+ a curr5t ?r\gh ! body to be anneal$1 & heat+ x to r$ness2 !n all[+ x to cool gradually4 ,annunciator4 ,an app>atus = giv+ a call f "o place to ano!r1 z f a liv+-room to a hotel (fice1 or = designat+ a w9d[ or door t may h be5 op5$ :5 protect$ by a burgl>-al>m4 ,annunciator-drop4 ,! little %utt] :i* is dropp$ by "s =ms ( annunciators1 & ^: fall discloses a numb] or lett]1 designat+ ! location f :i* ! call 0 s5t4 ,anode4 ,! positive t]m9al 9 a brok51 metallic1 or true conduct+ circuit4 ,! t]m9al connect$ to ! c>bon-plate ( a batt]y1 or to its equival5t 9 any o!r =m ( electric g5]ator1 su* z a dynamo or a voltaic pile4 ,! copp]1 nickel1 gold1 or silv] plates hung 9 an electro-plat+ ba?1 & f :i* ! metal is suppli$ to fill ! defici5cy made by ! electro-deposition ( metal on ! ka?ode or negative object 9 ! ba?4 ,anti-hum4 ,a %ackle ins]t$ directly 9 a l9e-wire ne> a pole4 ,x is provid$ ) a wa%] or cu%ion ( rubb] to take up ! vibrations ( a wire4 ,to cont9ue ! circuit a bridle1 or curv$ piece ( wire1 is connect$ ) ! l9e-wires t are atta*$ to ! %ackle4 ,arc4 ,a t]m appli$ to an electric curr5t fl[+ f c>bon to c>bon1 or f metals sep>at$ by a %ort gap1 z 9 ! arc /reet-lamps4 ,! orig9al arc 0 produc$ by two v]tical rods1 ?r\gh :i* ! curr5t pass$ up & d[n4 ,:5 n 9 action ! upp] ends t\*$1 b z ! curr5t fl[$ ! ends 7 sep>at$1 s t ! curr5t1 pass+ up "o c>bon across ! gap & d[n ! o!r1 =m$ ! segm5t ( a circle 9 jump+ f "o tip to ! o!r4 ,an arc ( electric flame is ( brilliant & dazzl+ :it5ess4 ,! voltaic arc is ! s\rce ( ! mo/ int5se heat & light yet produc$ by man4 ,! light is due pr9cipally to ! inc&esc5ce ( ! ends ( c>bon-p5cils1 :5 a curr5t ( suffici5t /r5g? is pass+ ?r\gh !m & jump+ ov] ! gap4 ,und\bt$ly ! transf]r$ c>bon p>ticles h mu* to d ) its =mation4 ,! conductivity ( ! int]v5+ air & ! int5se heat+ to :i* x is subject$1 toge!r ) its coeffici5t ( resi/ance1 are o!r factors 9 ! brilliant light produc$4 ,arc-lamp4 ,an electric lamp :i* d]ives its light f ! voltaic arc1 by means ( c>bon-p5cils & a curr5t jump+ f "o to ! o!r4 ,arc1 ,quiet4 ,an arc free f ! hiss+ s\nd s common 9 arc-lights4 ,arc1 ,simple4 ,a voltaic arc produc$ betwe5 only two electrodes4 ,armature4 ,a body ( iron or o!r mat]ial susceptible to magnetization1 & :i* is plac$ on or ne> ! poles ( a magnet4 ,t "p ( an electric me*anism :i* by magnetism is drawn to or repell$ f a magnet4 ,! core ( a dynamo or motor :i* revolves )9 ! field magnets1 & :i* is ! active pr9ciple 9 ! g5]ation ( curr5t by me*anical means1 or 9 ! di/ribution ( p[] ?r\gh electrical influ5ce4 ,armatures are sometimes made ( /eel1 & are p]man5t magnets4 ,^! are us$ 9 magneto-g5]ators1 telegraph in/rum5ts1 & o!r app>atus4 ,armature-b>4 ,an armature 9 a dynamo or motor ^: w9d+ is made up ( conductors 9 ! =m ( b>s4 ,armature-coil4 ,! insulat$ wire w\nd ar\nd ! core ( ! armature ( an electric curr5t-g5]ator or motor4 ,armature-core4 ,! c5tral mass ( iron on :i* ! insulat$ wire is w\nd2 x is rotat$ 9 ! field ( an electric curr5t-g5]ator or motor4 ,armor$4 ,protect$ by armor2 z cables may be surr\nd$ by a prop] %ea?+ to gu>d !m f injury4 ,a/atic4 ,hav+ no magnetic directive t5d5cy1 ! latt] be+ a g5]al consequ5t ( ! e>?'s magnetism4 ,a/atic ,circuit4 7,see ,circuit1 ,a/atic47 ,a/atic ,c\ple4 7,see ,c\ple1 ,a/atic47 ,a/atic ,ne$le4 ,a comb9ation ( two magnetic ne$les s adju/$ z to h z slight directive t5d5cy z possible4 ,! comb9ation is g5]ally made up ( two ne$les arrang$ "o above ! o!r ) ! poles 9 opposite directions--commonly call$ 8,nobili's ,pair40 ,^! ne$les require b a slight electro-=ce to turn !m "o way or ! o!r1 & are us$ 9 a/atic galvanomet]s4 ,atmosph]ic ,electricity4 7,see ,electricity1 ,atmosph]ic47 ,atom4 ,! ultimate p>ticle or division ( an elem5t>y sub/ance4 ,electricity is l>gely responsible = ! pres5ce ( atoms 9 ! atmosph]e4 ,atomic ,attraction4 ,! attraction ( atoms = ea* o!r4 ,pr9cipally due to electric di/urbance4 ,attraction4 ,! t5d5cy to approa* & adh]e or coh]e :i* is %[n 9 all =ms ( matt]4 ,x includes gravitation1 cohesion1 adhesion1 *emical aff9ity1 electro-magnetic & dynamic attraction4 ,aurora4 ,a lum9\s electric display se5 9 ! nor!rn heav5s4 ,x is commonly ?\ght to be ! electric dis*>ges ( ! e>? into ! atmosph]e1 due to revolution ( ! =m] & to ! heat produc$ at ! equator4 ,z comp>$ to ! /atic ma*9e = g5]at+ frictional electricity1 ! e>? repres5ts ! revolv+ :eel ga!r+ ! curr5t & dis*>g+ x at ! poles4 ,automatic ,cut-out4 ,an electro-magnetic swit* introduc$ into a circuit1 s z to break ! circuit ( ! latt] %\ld x become ov]load$ ) curr5t2 x also acts 9 ! ev5t ( a me*anical int]ruption4 ,automatic ,regulation4 ,a spe$ regulator work$ by electricity s t a uni=m fl[ ( curr5t may be secur$ automatically4 ,ayrton's ,cond5s]4 ,?is is a pile ( glass plates sep>at$ by small pieces ( glass at ! f\r com]s1 s t ! plates _c t\* ea* o!r4 ,t9-foil is pa/$ on bo? sides ( e plate1 & ! two coat+s are connect$4 ,! t9-foil on ea* second plate is small] 9 area ?an t on ! o!rs1 & ! plates are connect$ 9 two sets1 negative & positive4 ,9 ?is con/ruction x w be se5 t ! glass is n ! dielectric prop]1 b acts only z ! plane to :i* ! t9-foil is pa/$4 ,"o set ( plates are connect$ to a b9d+-po/ by /rips ( t9-foil1 & ! o!r set are connect$ to ano!r b9d+-po/ 9 a simil> mann]4 ,b ,b4 ,an abbreviation = ,beaum1 ! inv5tor ( ! hydromet] scale4 ,?us1 9 speak+ ( ! gravity ( fluids1 #bj ,b4 means tw5ty degrees ,beaum4 ,back ,induction4 ,a demagnetiz+ =ce produc$ 9 a dynamo :5 a lead is giv5 to ! bru%es4 7,see also ,induction1 ,back47 ,back ,%ock4 ,a lightn+ /roke receiv$ aft] ! ma9 dis*>ge4 ,x is caus$ by a *>ge induc$ 9 neighbor+ surfaces by ! ma9 dis*>ge4 ,bad ,e>?4 ,a poor gr\nd connection1 or "o hav+ comp>atively /rong electrical resi/ance4 ,balance4 ,a prop] adju/m5t betwe5 ! app>atus & ! electro-motive =ce1 ?us secur+ ! be/ possible results4 ,b4 ,s4 ,w-,g4 ,abbreviations = ,br[n ,%>p & wire-gauge1 & ref]r+ to ! sizes ( wire & %eet-metal ?icknesses t are consid]$ /&>ds 9 ,am]ica4 ,b>-armature4 ,an armature 9 :i* ! conductors are con/ruct$ ( b>s4 ,b>-magnet4 ,"o ^: core pres5ts ! appe>ance ( a /raight b>1 or rod1 )\t curve or b5d4 ,b>e-c>bons4 ,electric light c>bons ^: surfaces are n electro-plat$ ) copp]4 ,b>omet]4 ,an app>atus = measur+ ! pressure ex]t$ by ! atmosph]e4 ,x consi/s ( a glass tube #ca in*es long1 clos$ at "o end1 fill$ ) m]cury1 & !n inv]t$1 ) its op5 end imm]s$ 9 a ci/]n ( m]cury4 ,! column ( m]cury falls to a height proportional to ! pressure ( ! atmosph]e4 ,at ! sea-level x ranges f #cj to #ca in*es4 ,b>-w9d+s4 ,! w9d+s ( an armature con/ruct$ ( copp] b>s4 ,ba?4 ,9 electro-plat+1 ! solution or electrolyte us$ = deposit+ metal on ! object to be plat$4 ,x may be a solution ( copp]1 silv]1 nickel1 or o!r metal4 ,9 electro-!rapeutics x is a ba? ( wat] ) suitable electrodes & connections = treat+ pati5ts ) electricity4 ,ba?-/ripp+4 ,a solution us$ = /ripp+ or remov+ ! metal plat+ f an object4 ,batt54 ,a /rip ( wood groov$ longitud9ally1 9 :i* electric light or p[] wires are set4 ,! groov$ /rip is screw$ to ! wall1 ! wires be+ laid 9 ! grooves1 & !n cov]$ ) a ?9 wood5 /rip fa/5$ on ) small nails4 ,batt]y4 ,a comb9ation ( p>ts1 or elem5ts1 = ! production ( electrical action4 ,a numb] ( cells connect$ p>allel or 9 s]ies = ! g5]ation ( electricity4 ,"u ?is head+ !re are at lea/ "o hundr$ diff]5t k9ds4 ,n[adays ! dynamo is ! *eap & effici5t g5]ator ( electricity4 ,batt]y ,cell1 ,elem5ts (4 ,! plates ( z9c & c>bon1 or ( z9c & copp]1 9 a cell are call$ elem5ts4 ,! plate unattack$ by ! solution1 su* z ! c>bon or copp]1 is ! negative elem5t1 :ile ! "o attack$ & corrod$ by ! electrolyte is ! positive4 ,batt]y1 ,dry4 ,a =m ( op5 circuit cell 9 :i* ! electrolyte is made practically solid1 s t ! cell may be plac$ 9 any position4 ,a z9c cup is fill$ ) ! electrolyte & a c>bon-rod plac$ 9 ! middle1 c>e be+ tak5 to avoid contact betwe5 cup & c>bon at ! bottom ( ! cell4 ,! gelat9\s *emical mass is !n pack$ 9 closely ab\t ! c>bon1 s z to ne>ly fill ! cup4 ,a capp+ ( asphaltum1 wax1 or o!r non-conduct+ & seal+ mat]ial is plac$ ov] ! electrolyte1 & ?is h>d5s ab\t ! c>bon & ar\nd ! top inn] edge ( ! z9c cup4 ,! latt] becomes ! positive pole1 ! c>bon ! negative4 ,b9d+-po/s1 or connections1 may be atta*$ to ! z9c & c>bon to facilitate connections4 ,batt]y1 ,galvanic4 ,! old "n = a voltaic batt]y4 ,batt]y1 ,gravity4 ,a batt]y 9 :i* ! sep>ation ( fluids is obta9$ ?r\gh _! diff]5ce 9 specific gravity--= example1 ! blue/one cell4 ,! sulphate ( copp] solution1 be+ ! m d5se1 goes to ! bottom1 :ile ! z9c solution /ays at ! top4 ,9 its action ! acid at ! top corrodes ! z9c1 :ile at ! bottom ! solution is decompos$ & deposits metallic copp] on ! ?9 copp] plates4 ,batt]y1 ,leclan*4 ,an op5 circuit batt]y consi/+ ( a j>1 a por\s cup1 & ! c>bon & z9c elem5ts1 ! electrolyte ( :i* is a solution ( ammonium *loride 7sal-ammoniac74 ,! c>bon plate is plac$ 9 ! por\s cup1 & pack$ 9 ) a mixture ( p[d]$ manganese b9oxide & graphite1 to s]ve z a depol>iz]4 ,a half-saturat$ solution ( sal-ammoniac is plac$ 9 ! out] j>1 & a rod ( z9c susp5d$ 9 x4 ,ano!r =m ( ! batt]y is to omit ! por\s cup & use twice ! bulk ( c>bon1 bo? elem5ts be+ susp5d$ 9 ! "o solution ( sal-ammoniac2 ?is =m ( batt]y is us$ = op5-circuit "w only1 su* z bells1 buzz]s1 & annunciators4 ,x is n adapt$ = lights1 p[]1 or plat+ purposes4 ,batt]y ,mud4 ,a deposit ( mud-l "* :i* =ms at ! bottom ( gravity batt]ies1 & :i* consi/s ( metallic copp] precipitat$ by ! z9c4 ,x only occurs :]e wa/eful action has tak5 place4 ,batt]y ( ,dynamos4 ,a t]m us$ 9 speak+ ( a numb] ( dynamos c\pl$ to supply ! same circuit4 ,!y may be c\pl$ 9 s]ies or p>allel4 ,batt]y1 ,plunge4 ,a batt]y 9 a cab9et or frame1 s arrang$ t ! active plates c be remov$ or rais$ out ( ! solutions4 ,?is is usually accompli%$ by hav+ ! plates atta*$ to a movable frame :i*1 by means ( a rat*et-%aft & *a9s1 c be rais$ or l[]$4 ,its object is to prev5t ! corrosion ( ! plates :5 n 9 use4 ,batt]y1 ,prim>y4 ,a voltaic cell or batt]y g5]at+ electric en]gy by direct consumption ( mat]ial4 ,! ord9>y voltaic cell1 or galvanic batt]y1 is a prim>y batt]y4 ,batt]y1 ,second>y4 ,a /orage-batt]y1 an accumulator4 ,batt]y ,solution4 ,! active excitant liquid1 or electrolyte1 plac$ )9 a cell to corrode ! positive elem5t4 ,also call$ ,electropoion4 ,batt]y1 ,/orage4 ,a second>y batt]y2 an accumulator2 a batt]y :i* accumulates electricity g5]at$ by prim>y cells or a dynamo4 ,batt]y-gauge4 ,a galvanomet] us$ = te/+ batt]ies & connections4 ,x is usually small 9 size1 & may be c>ri$ 9 a pocket4 ,batt]y-j>4 ,a glass1 e>!n1 or lead vessel :i* conta9s ! fluids & elem5ts ( ea* sep>ate cell ( a batt]y4 ,baum ,hydromet]4 7,see ,hydromet]1 ,baum47 ,becqu]el ,ray & ,radiation4 ,an invisible ray discov]$ by ,becqu]el1 :i* is giv5 out by "s comp\nds & *emicals--notably uranium--& :i* has ! p[] to p5etrate _m opaque bodies & objects imp5etrable to ! act9ic rays ( ord9>y light4 ,^! rays are us$ *iefly 9 connection ) ! photographic dry-plate4 ,bell1 ,electric4 ,a bell rung by electricity4 ,! curr5t excites an electro-magnet1 attract+ or releas+ an armature :i* is atta*$ to a vibrat+ or pivot$ arm1 on ! end ( :i* ! knock] is fa/5$4 ,bi*romate ( ,pota%4 ,a /rong1 yell[i%-r$ *emical1 us$ *iefly 9 batt]y fluids & electrolytes4 ,bifil> ,w9d+4 ,! me?od foll[$ 9 w9d+ resi/ance-coils4 ,to prev5t !m f creat+ fields ( =ce1 ! wire is d\bl$ & ! loop$ end />t$ 9 ! coil4 ,s9ce ! curr5t passes 9 opposite s5ses 9 ! two lays ( ! w9d+1 no field ( =ce is produc$4 ,b9d+4 ,unatta*$ wire w\nd r\nd armature-coils to hold !m 9 place4 ,b9d+-po/4 ,an arrangem5t = receiv+ ! loose ends ( wires 9 an electric circuit & secur+ !m1 by means ( screws1 s t p]fect contact w be ! result4 ,bi-pol>4 ,possess+ two poles4 ,bi-telephone4 ,a pair ( telephones arrang$ ) a curv$ connect+ arm or spr+ s t !y c be simultane\sly appli$ to bo? e>s4 ,bla/+1 ,electric4 ,! ignition ( a bla/+ *>ge ( p[d]1 dynamite1 or o!r high explosive by an electric sp>k1 or by ! heat+1 to r$ or :ite heat1 ( a ?9 wire imb$d$ 9 ! explosive4 ,block ,sy/em4 ,a sy/em ( signall+ on railroads4 ,signal-po/s are arrang$ at /at$ spaces1 & on ^! signals appe> automatically1 %[+ ! location ( tra9s to ! eng9e]s ( tra9s 9 ! re>4 ,blue/one4 ,a trade "n = sulphate ( copp] 9 a cry/alliz$ /ate4 ,bobb94 ,a spool ( wood or o!r non-conduct+ sub/ance w\nd ) insulat$ wire4 ,9 a tang5t galvanomet] ! bobb9 becomes a r+ ) a *annel to receive ! wire4 ,boil+4 ,9 second>y1 or /orage1 batt]ies ! escap+ ( hydrog5 & oxyg5 gases1 :5 ! batt]y is fully *>g$1 resembles wat] boil+4 ,bond$ ,rails4 ,rails us$ 9 an electric traction sy/em1 & :i* are l9k$ or connect$ toge!r to =m a p]fect circuit4 ,us$ pr9cipally 9 ! ?ird-rail sy/em4 ,brake1 ,electro-magnetic4 ,a brake to /op ! :eels ( a mov+ c>4 ,x consi/s ( a %oe1 or r+1 :i* by magnetic =ce is drawn aga9/ a rotat+ :eel to /op its revolution4 ,bran*4 ,a conductor :i* leads (f f a ma9 l9e to di/ribute curr5t locally4 ,brass+4 ,a process ( electro-deposit+ brass 9 a ba? conta9+ bo? copp] & z9c4 ,a plate ( brass is us$ z an anode4 ,braz+1 ,electric4 ,a process 9 :i* ! spelt] is melt$ by electric curr5t1 s t ! two p>ts are unit$ z "o4 ,break4 ,a po9t :]e an electric conductor is brok51 z by a swit* or a cut-out4 ,bridge4 ,a special b> ( copp] connect+ ! dynamos ) ! bus wire 9 electric light+ or p[] /ations4 ,bronz+4 ,! deposition ( bronze by electro-plat+ me?ods4 ,! mixture is ( copp] & t91 & a ca/ bronze plate is us$ z an anode4 ,bru%4 ,a t]m appli$ to ! pieces ( copp]1 c>bon1 or o!r conduct+ m$ium 9 dynamos & motors1 t be> aga9/ ! cyl9drical surface ( ! commutators to collect or fe$ 9 ! curr5t4 ,bug4 ,any fault or tr\ble 9 ! connections or work+s ( an electrical app>atus4 ,! t]m orig9at$ 9 quadruplex telegraphy1 & probably _h "s connection ) ! ,edison bug-kill] t he inv5t$ :5 a boy4 ,buoy1 ,electric4 ,a buoy to indicate dang]\s *annels 9 h>bors & to m>k wrecks & reefs4 ,x is provid$ ) an electric light at night1 & ) a gong or an electric horn by day4 ,burn]1 ,electric4 ,a gas-burn] s arrang$ t ! flame may be light$ by electricity op]at$ by a pu%-button at "s di/ance f ! fixture1 or1 close at h&1 by means ( a *a9 or pull-/r+4 ,burn+4 ,9 a dynamo1 ! improp] contact ( bru%es & commutator1 :]eby a sp>k is produc$ & an arc =m$ :i* g5]ates heat & causes ! metal p>ts to burn4 ,bus-rod4 ,a copp] conductor us$ 9 p[]-plants to receive ! curr5t f ! batt]y ( dynamos4 ,! di/ribut+ leads are connect$ to ^! rods4 ,butt-jo9t4 ,a jo9t made by br++ ! ends ( wires toge!r s t ! ends butt4 ,!y are !n sold]$ or braz$4 ,button1 ,electric4 ,a =m ( swit* t is op]at$ by pu%+ a button m\nt$ on a suitable base4 ,us$ pr9cipally = r++ bells1 op]at+ lights1 etc4 ,buzz]4 ,an electric al>m1 or call1 produc$ by ! rapid vibration ( an armature act$ ^u by electro-magnetism4 ,! s\nd is magnifi$ by enclos+ ! me*anism 9 a resonant box4 ,an app>atus resembl+ an electric bell m9us ! bell & clapp]4 ,! buzz] is us$ 9 places :]e ! l\d r+ ( a bell w\ld be a nuisance4 ,c ,c4 ,an abbreviation = c5tigrade :5 speak+ ( !rmal temp]ature4 ,9 *emi/ry ! c5tigrade scale is us$ ext5sively1 b 9 air temp]atures ! ,fahr5heit scale is univ]sally employ$4 ,cable1 ,a]ial4 ,a cable t conta9s a numb] ( wires sep>ately insulat$1 ! entire mass be+ protect$ by an ext]nal insulation4 ,x is susp5d$ 9 ! air f pole to pole1 & sometimes its weight is s great t a support+ wire is c>ri$ along ) x 7usually ov]head71 ! l>ge cable be+ susp5d$ f x by cable-hang]s4 ,cable ,box4 ,a box to receive cable ends & protect !m2 also1 ! box 9 :i* cable ends & l9e-wires are jo9$4 ,subm>9e cable boxes are usually ne> ! gr\nd1 :ile telephone & telegraph cable boxes are m\nt$ on poles1 ! cables runn+ f ! gr\nd & up ! poles to ! boxes4 ,cable-core4 ,! conductors ( a cable :i* make up its int]ior mass4 ,= ! conv5i5ce ( l9em5 ! wires are (t5 insulat$ ) diff]5t-color$ mat]ials s t te/+ is n necess>y :5 mak+ connections4 ,cable-hang]4 ,a metallic grip1 usually ( %eet metal1 arrang$ to clasp two or m wires4 ,x is fa/5$ to ! support+ wire by a hook & eye1 or by small bolts ) ?umb-nuts4 ,cable-head4 ,a rectangul> bo>d equipp$ ) b9d+-po/s & fuse wires s t ! connections may be made betwe5 ! cable ends & ! ov]head or l9e-wires ( a sy/em4 ,cables4 ,an insulat$ electric conductor ( l>ge diamet]1 (t5 protect$ by armor or metallic %ea?+1 & g5]ally conta9+1 or made up1 ( sev]al sep>ately insulat$ wires4 ,cables supply curr5t to traction l9es2 p[]1 ?r\gh subt]ranean passages2 communication1 by subm>9e connection2 & light1 by ov]head or und]gr\nd conduits4 ,call-bell4 ,a bell t is rung by press+ a button1 & :i* is op]at$ by electricity4 ,call+-drop4 ,a drop-%utt] :i* is work$ by electricity 9 a telegraph or telephone ex*ange2 x d5otes ! location f :i* ! call 0 s5t 94 ,small r$ inc&esc5t lamps h tak5 ! place ( ! drops 9 mo/ ( ! l>ge telephone ex*anges1 = !y are noiseless & d n annoy ! op]ators z ! drops & buzz]s did4 ,c&le-p[]4 ,! am\nt ( light giv5 by ! /&>d c&le4 ,! legal ,engli% & ,am]ican /&>d is a sp]m c&le burn+ two gra9s a m9ute4 ,c&le1 ,/&>d4 ,! /&>d ( illum9at+ p[]2 a flame :i* consumes two gra9s ( sp]m wax p] m9ute1 & produces a light ( a brightness equal to "o c&le-p[]4 ,ca\t*\c4 ,india-rubb]4 ,s nam$ because orig9ally its *ief use 0 to erase or rub (f p5cil m>ks4 ,x is a sub/ance exi/+1 9 a ?ick fluid /ate1 9 ! sap or juices ( c]ta9 tropical trees & v9es2 x possesses a v high value z an insulator = wire & circuits4 ,! unwork$1 crude rubb] is call$ virg9 gum1 b aft] x is knead$ x is call$ ma/icat$ or pure gum rubb]4 ,capacity4 ,a t]m us$ :5 speak+ ( ! c>ry+ p[] ( a wire or circuit4 ,! capacity ( a wire1 rod1 b>1 or o!r conductor is suffici5t s long z ! curr5t does n heat x4 ,directly electric heat is g5]at$1 we speak ( ! conductor z be+ ov]load$ or hav+ its capacity ov]tax$4 ,capacity ( a ,telegraph ,conductor4 ,! electric capacity may be id5tical 9 quality ) t ( any o!r conductor4 ,9 quantity x v>ies n only 9 diff]5t wires1 b = ! same wire "u diff]5t conditions4 ,a wire react+ ?r\gh ! surr\nd+ air1 or o!r dielectric1 ^u ! e>? repres5ts "o elem5t ( a cond5s]1 ! e>? 9 g5]al repres5t+ ! o!r4 ,a wire plac$ ne> ! e>? has great] capacity ?an "o /rung ^u high poles1 al?\gh ! wires may be ( id5tical l5g? & size & ( ! same metal4 ,! effect ( high capacity is to ret>d ! transmission ( curr5t1 ! l[ capacity facilitates transmission4 ,capacity1 ,/orage4 ,9 second>y batt]ies1 ! quantity ( electric curr5t !y c supply1 :5 fully *>g$1 )\t exhau/ion4 ,?is capacity is measur$ or reckon$ 9 amp]e-h\rs4 ,c>bon4 ,"o ( ! elem5ts 9 graphitic =m us$ z an electric-curr5t conductor4 ,x is ! only sub/ance :i* conducts electricity1 & :i* _c be melt$ ) comp>ative ease by increase ( curr5t4 ,x exi/s 9 ?ree modifications--*>coal1 graphite1 & ! diamond4 ,9 its graphitic =m x is us$ z an electro-curr5t conductor1 z 9 batt]ies & arc-light electrodes1 & z filam5ts 9 inc&esc5t lamps4 ,9 arc-lamp use ! c>bons are usually electro-plat$ on ! outside ) a film ( copp] :i* acts z a bett] conductor4 ,c>bon1 ,artificial4 ,c>bon-du/1 p[d]$ coke1 or gas c>bon is mix$ ) molasses1 coal-t>1 syrup1 or "s simil> c>bonace\s fluid1 s t ! mass is pla/ic4 ,x c !n be m\ld$ or press$ into %apes1 & heat$ to full r$ness = sev]al h\rs by artificial or electric heat4 ,= lamp-c>bons ! mixture is =c$ ?r\gh a r\nd die by heavy pressure1 & is cut into suitable l5g?s1 !n fir$ or bak$4 ,aft] remov+ & cool+1 ! c>bons are sometimes dipp$ aga9 into ! fluid us$ = cem5t+ ! orig9al mass & re-ignit$4 ,?is process is t]m$ 8n\ri%+40 ,all c>bon is a resi/+ m$ium1 b at high temp]ature ! resi/ance is only ab\t "o-?ird z great2 t is1 ! curr5t w pass ?r\gh a r$-hot c>bon ?ree times bett] ?an ?r\gh ! cold c>bon2 or a curr5t ( ?irty amp]es w be conduct$ z easily ?r\gh a hot c>bon z t5 amp]es ?r\gh a cold "o4 ,c>bon-cor$4 ,a c>bon = arc-lamps1 ! core be+ ( s(t] c>bon ?an ! out] surface4 ,x is suppos$ to give a /eadi] light1 & fixes ! position ( ! arc4 ,c>bon-dioxide4 ,a comp\nd gas1 or c>bonic-acid gas4 ,x is a dielectric4 ,c>bon-hold]s4 ,9 arc-lamps1 ! clamps arrang$ to hold ! c>bon-p5cils4 ,c>bonization4 ,! ignition ( an organic sub/ance 9 a clos$ vessel1 s z to expel all con/itu5ts f x except ! c>bon4 ,a de/ructive di/illation4 ,c>bon ,resi/ance4 7,see ,resi/ance1 ,c>bon47 ,c>bon ,volatilization4 ,9 arc-lamps ! heat is s int5se t x is believ$ a "p ( ! c>bon-p5cil is volatiliz$1 z vapor1 be=e be+ burn$ or oxidiz$ by ! oxyg5 ( ! air4 ,c>bons1 ,b>e4 7,see ,b>e ,c>bons47 ,c>ry+ ,capacity4 ,9 a curr5t-conductor1 its c>ry+ capacity up to ! heat+-po9t4 ,x is express$ 9 amp]es4 ,cascade4 ,! arrangem5t ( a s]ies ( ,leyd5-j>s 9 prop]ly insulat$ /ools1 or supports1 = accumulat+ frictional electricity4 ,!y are arrang$ 9 a mann] some:at simil> to a batt]y ( galvanic cells1 ! inn] coat+ ( "o be+ connect$ to ! out] coat+ ( ! next1 & s on ?r\gh ! s]ies4 ,case-h>d5+1 ,electric4 ,a process by :i* ! surface ( iron is conv]t$ into /eel by apply+ a prop] c>bonace\s mat]ial to x :ile x is be+ heat$ by an electric curr5t4 ,caut]y1 ,electric4 ,an electro-surgical appliance = remov+ diseas$ p>ts or arre/+ hemorrhages4 ,x takes ! place ( ! knife or o!r cutt+ in/rum5t4 ,x is a loop ( plat9um wire heat$ to :it5ess by an electric curr5t4 ,c4,c4 ,an abbreviation commonly us$ = cubic-c5timet]4 ,x is usually writt5 9 small lett]s1 z #ej c4c41 mean+ #ej cubic-c5timet]s4 ,cell1 ,electrolytic4 ,a vessel conta9+ ! electrolyte us$ = electro-plat+4 ,cell1 ,reg5]at$4 ,a cell re/or$ to its prop] functions by a process ( re*>g+4 ,cell1 ,/&>d4 ,mean+ ! same z batt]y4 ,! vessel1 includ+ its cont5ts1 9 :i* electricity is g5]at$4 ,cell1 ,/orage4 ,two plates ( metal1 or comp\nds ( metal1 ^: *emical relations are *ang$ by ! passage ( an electric curr5t f "o plate to ! o!r ?r\gh an electrolyte 9 :i* !y are imm]s$4 ,cem5ts1 ,electrical4 ,cem5ts ( a non-conduct+ nature1 su* z m>9e glue & /icky comp\nds1 us$ 9 electrical "w4 ,c5trifugal ,=ce4 ,a diametric revolv+ =ce :i* ?r[s a body away f its axis ( rotation4 ,a m]ry-g-r\nd is a simple example ( ?is =ce4 ,! m rapidly ! plat=m revolves ! great] ! t5d5cy = ^? on x to be ?r[n (f & out f ! c5tre4 ,! high velocity atta9$ by ! armatures 9 motors & dynamos w\ld ?r[ ! wires out ( place & cause !m to rub aga9/ ! surfaces ( ! field-magnets4 ,consequ5tly1 wire b&s or b9d]s are necess>y to keep ! coils ( wire f spread+ "u ! influ5ce ( ! c5trifugal =ce4 ,*>ge4 ,! quantity ( electricity t is pres5t on ! surface ( a body or conductor4 ,! compon5t *emical p>ts t are employ$ to excite ! elem5ts ( a cell 9 g5]at+ electric curr5t4 ,*>ge1 ,residual4 ,aft] a ,leyd5-j>1 or o!r cond5s]1 has be5 dis*>g$ by ! ord9>y me?ods1 a second dis*>ge 7( less am\nt7 c be _h aft] a few m9utes' wait+4 ,?is is due to :at is kn[n z ! residual *>ge1 & is connect$ 9 "s way ) ! molecul> di/ortion ( ! dielectric4 ,*emical ,*ange4 ,:5 bodies unite s z to satisfy aff9ity1 or to br+ ab\t ! free+ ( !rmal or o!r en]gy1 ! union is usually accompani$ by s5sible heat or light4 ,sulphuric acid add$ to wat] produces heat2 a mat* 9 burn+ produces light4 ,ano!r =m ( *emical *ange is decomposition or sep>ation 7! rev]se ( comb9ation71 su* z takes place 9 ! voltaic-batt]y1 ! electro-plat+ ba?1 & o!r =ms ( electrolysis4 ,?is is n accompani$ by heat or light1 b by ! evolution ( electricity4 ,*emical ,elem5t4 7,see ,elem5t1 ,*emical47 ,*emi/ry4 ,! sci5ce :i* treats ( ! atomic & molecul> relations ( ! elem5ts & _! *emical comp\nds4 ,*emi/ry is divid$ into _m dep>tm5ts1 b electro-*emi/ry treats only ( ! sci5ce :]e9 electricity plays an active "p1 su* z batt]ies1 electro-plat+1 & electro-metallurgy4 ,*ok+-coil4 7,see ,coil1 ,*ok+47 ,circle1 ,magic4 ,a =m ( electro-magnet4 ,x is a ?ick circle ( r\nd iron us$ 9 connection ) a magnetiz$ coil to illu/rate electro-magnetic attraction4 ,circuit4 ,a conduct+-pa? = electric curr5ts4 ,prop]ly speak+1 a complete circuit has ! ends jo9$1 & includes a s\rce ( curr5t1 an app>atus1 & o!r elem5ts introduc$ 9 ! pa?4 ,:5 ! circuit is complete x is call$ active4 ,! t]m circuit is also appli$ to portions ( a true circuit--z1 an int]nal or ext]nal circuit4 ,circuit1 ,a/atic4 ,a circuit s w\nd1 ) ref]5ce to ! direction ( ! curr5ts pass+ ?r\gh x1 t ! t]re/rial or o!r l9es ( =ce h no directive effect ^u x4 ,circuit-break]4 ,any app>atus = op5+ & clos+ a circuit1 su* z swit*es1 automatic cut-outs1 lightn+-arre/]s1 & ! l4 ,a rat*et-:eel engag$ ) a spr+1 or wire1 :i* re/s aga9/ ! tee?4 ,! curr5t passes ?r\gh ! wire1 ! :eel1 & axle4 ,! :eel is revolv$ by a crank1 & z ! rat*ets pass ! spr+1 or wire1 an in/antane\s make-&-break occurs4 ,! spe$ ( ! :eel regulates ! frequ5cy ( ! int]ruptions4 ,circuit1 ,ext]nal4 ,a portion ( ! circuit n includ$ )9 ! g5]ator1 su* z a second>y telegraph key & s\nd]4 ,circuit1 ,gr\nd$4 ,a circuit 9 :i* ! gr\nd is us$ z a conductor4 ,?is is common 9 telegraph & telephone l9es1 p>ticul>ly = %ort di/ances :]e ! conductivity ( ! e>? does n (f] too mu* resi/ance4 ,circuit1 ,inc&esc5t4 ,a circuit 9 :i* inc&esc5t lamps are in/all$4 ,circuit ,indicator4 ,a pocket-compass1 galvanomet]1 or o!r device = indicat+ or detect+ ! condition ( a wire1 :e!r x is active or dead1 &1 if active1 9 :i* direction ! curr5t is fl[+4 ,x may also give a g5]al idea ( its /r5g?4 ,circuit1 ,int]nal4 ,t portion ( an electric circuit :i* is includ$ )9 ! g5]ator4 ,circuit ,loop4 ,a m9or circuit introduc$1 9 s]ies1 into ano!r circuit by a swit* or cut-out1 s t x becomes a "p ( ! ma9 circuit4 ,circuit1 ,ma94 a circuit or ma9 l9e1 includes ! app>atus supply+ curr5t to x4 ,?us di/+ui%$ f a local circuit4 ,circuit1 ,metallic4 ,a circuit 9 :i* ! curr5t outside ! g5]ator passes ?r\gh metal p>ts or wire1 b n ?r\gh ! gr\nd4 ,electric light & p[] l9es are always metallic circuits4 ,an electro-plat+ app>atus may be prop]ly t]m$ a metallic circuit1 al?\gh a "p ( ! circuit is =m$ by ! electrolyte 9 ! ba?4 ,! ess5tial mean+ ( ! words metallic circuit is t ! e>? does n =m a "p ( ! return circuit4 ,circuit1 ,op54 ,a circuit 9 :i* a swit* has be5 op5$ to prev5t ! cont9u\s fl[ ( curr5t1 su* z an electric-bell circuit1 :i* normally rema9s op51 & :i* is active only :5 ! pu%-button is press$1 !reby clos+ ! circuit & op]at+ ! bell4 ,an op5-circuit batt]y is "o t rema9s inactive :5 ! circuit is op54 ,circuit1 ,p>allel4 ,a t]m signify+ a multiple circuit4 ,circuit1 ,quadruple4 ,a s+le circuit capable ( hav+ f\r messages transmitt$ ov] x simultane\sly--two 9 "o direction1 & two 9 ! o!r4 ,circuit1 ,return4 ,9 telegraphy ! gr\nd is us$ z ! return circuit4 ,x is also t portion ( a circuit :i* leads f an app>atus back to ! t]m9al ( a dynamo or batt]y1 usually ! negative wire4 ,circuit1 ,%ort4 ,a connection betwe5 two p>ts ( a circuit1 caus+ ! curr5t to skip a great "p ( its appo9t$ pa?4 ,%ort-circuits prev5t ! prop] work+ ( any electrical app>atus4 ,circuit1 ,simple4 ,a circuit conta9+ a s+le g5]ator1 ! prop] wire = c>ry+ ! curr5t1 & a swit* to op]ate x4 ,an electric-bell l9e1 a s+le telegraph l9e1 or a direct telephone l9e are all simple circuits4 ,clamp4 ,a tool = grasp+ & hold+ ! ends ( wires :ile jo9+ !m4 ,! appliance = hold+ ! c>bon-p5cils 9 arc-lamps4 ,cleats4 ,blocks ( wood1 porcela91 or o!r insulat+ mat]ial us$ to hold wires aga9/ a wall or beam4 ,!y h "o1 two1 & ?ree not*es at "o side1 = s+le1 d\ble1 & ?ree wire sy/ems4 ,clut*1 ,electric4 ,a =m ( magnetic brake appli$ to c>-:eels1 ! armatures ( motors1 & o!r revolv+ me*anism1 :]eby ! curr5t1 pass+ ?r\gh a coil1 magnetizes a mass ( ca/-iron1 & br+s x to be> frictionally ^u ! mov+ p>ts ( ! me*anism4 ,code1 ,ciph]4 ,a set ( disconnect$ words :i*1 9 accordance ) a pre>rang$ key1 /& = :ole s5t5ces & phrases4 ,comm]cially ! sy/em is us$ z a %ort-cut--t5 words p]haps mean+ :at o!rwise x w\ld take =ty or fifty words to express4 ,x is us$ ext5sively 9 telegraphy1 bo? z an abbreviat$ message & z a means = secur+ secrecy4 ,coh]]4 ,conduct+ p>ticles con/itut+ a semi-conduct+ bridge betwe5 two electrodes1 & s]v+ to detect electro-magnetic waves4 ,! coh]] 9 wireless telegraphy is und]/ood to mean t =m ( radio-receiv] :i*1 be+ normally at high resi/ance1 is1 "u ! influ5ce ( ,h]tzian-waves1 *ang$ to a l[ resi/ance1 ?us becom+ relatively a conductor4 ,tubes ( v>i\s k9ds h be5 us$ = ?is purpose4 ,)9 !m is a fill+ ( c>bon granules1 copp] fil+s1 nickel & silv] fil+s1 & o!r sub/ances4 ,m>coni's coh]] consi/s ( a tube "o & "o-half in*es long & "o-twelf? in* int]nal diamet]4 ,?is is fill$ ) fil+s--#ij p] c5t4 ( nickel1 #aj p] c5t4 ( silv]4 ,a globule ( m]cury coats ! out] surface ( ea* gra9 ) a ?9 film ( ! quicksilv]4 ,into bo? ends a piece ( pure silv] wire is plugg$4 ,^! latt] are a qu>t] ( an in* long1 & fit ! tube v accurately4 ,! tube is ?us seal$1 & x is consid]$ pref]able to h a slight vacuum )9 x4 ,coil4 ,a /r& ( wire w\nd 9 circul> =m ab\t a spool1 a s(t-iron core1 or 9 lay]s1 z a coil ( rope4 ,an electro-magnetic g5]ator4 ,a helix4 7,see also ,induction1 ,resi/ance1 ,magnetiz+47 ,coil1 ,*ok+4 ,a =m ( resi/ance to regulate ! fl[ ( curr5t4 ,any coil ( insulat$ wire w\nd ^u a lam9at$ or divid$ iron core =ms a *ok+-coil4 ,9 alt]nat+-curr5t "w special *ok+-coils are us$4 ,!y h a movable iron core1 & by ?ru/+ x 9 or out ! p[] is increas$ or dim9i%$1 ?us rais+ or l[]+ ! lights1 ! same z gas is regulat$4 ,coil1 ,f>adic4 ,! "n giv5 to a m$ical induction-coil or f>adic ma*9e4 ,coil1 ,induction4 ,a coil 9 :i* ! electro-motive =ce ( a portion ( a circuit is1 by induction1 made to produce high] or l[] electro-motive =ces 9 an adjac5t circuit1 or 9 a circuit a "p ( :i* adjo9s ! orig9al circuit4 ,!re are ?ree pr9cipal p>ts to all induction-coils--! core1 ! prim>y coil1 & ! second>y coil4 ,! core is a mass ( s(t iron1 ca/ or wr\ght1 b pref]ably divid$--= example1 a bundle ( rods or b>s4 ,! prim>y coil ( comp>atively l>g] wire is w\nd ab\t ?is core1 ea* lay] be+ prop]ly insulat$ & v>ni%$1 or coat$ ) melt$ p>aff9e1 to b9d ! wires4 ,! second>y coil is ( f9e wire1 & is w\nd ab\t ! prim>y coil4 ,a great _m turns ( ! f9e wire are necess>y1 & c>e mu/ be tak5 to prop]ly insulate ea* lay] & %ellac ! wires4 ,! prim>y mu/ be well insulat$ f ! second>y coil1 s z to prev5t sp>k+1 :i* w\ld de/roy ! insulation4 ,a make-&-break is op]at$ by ! prim>y coil1 & is con/ruct$ ^u ! g5]al =m ( an electric bell or buzz] movem5t4 ,extra curr5ts :i* int]f]e ) ! action ( an induction-coil are avoid$ by ! use ( a cond5s]4 7,see also ,cond5s]47 ,! induction-coil produces a rapid succession ( sp>ks :i* may spr+ across a gap ( ?irty or =ty in*es1 accord+ to ! size ( ! coil4 ,induction-coils are us$ ext5sively 9 electric "w1 especially 9 telephone transmitt]s1 wireless telegraphy1 electric weld+1 & 9 ! alt]nat+-curr5t sy/em4 ,coil1 ,magnetiz+4 ,a coil ( insulat$ wire s w\nd t a well or ap]ture w be =m$4 ,)9 ?is well a piece ( /eel is plac$1 s t an electric curr5t1 pass+ ?r\gh ! wires1 w magnetize ! /eel2 or a /eel rod may be pass$ 9 & out ( ! hole sev]al times :ile a /rong curr5t is travell+ ?r\gh ! coil1 ?us magnetiz+ ! rod4 ,coil1 ,resi/ance4 ,a coil s con/ruct$ t x w (f] resi/ance to a /eady curr5t ( too great electro-motive =ce = ! safety ( ! app>atus4 ,g5]ally ! coil is made by d\bl+ ! wire )\t break+ x1 !n />t+ at ! d\bl$ end to w9d x 9 coil or spr+ fa%ion4 ,if ! wire is too heavy to w9d d\ble1 a s+le /r& is w\nd on a squ>e or triangul> insulator 9 :i* not*es are made4 ,!n1 alt]nately betwe5 ! coils1 ! second /r& is w\nd4 ,! /r&s are jo9$ at "o end ( ! coil1 b ^? at ! o!r are left free = unions ) o!r wires4 7,see also ,resi/ance47 ,coil1 ,ret>d+4 ,a *ok+-coil4 ,a resi/ance-coil4 ,coil1 ,ribbon4 ,in/ead ( wire1 flat1 ?9 /rips ( %eet-metal are sometimes us$ = resi/ance-coils1 d\bl$1 z expla9$ above4 ,! wraps are insulat$ ) %eet-mica1 micanite1 or asbe/os1 to prev5t %ort-circuit+4 ,coil1 ,ruhmkorff4 ,a common type ( induction-coil ) a vibrator or circuit-break]4 ,us$ ) con/ant & direct curr5t4 ,a /ep-up trans=m] ) a circuit-break] atta*m5t4 ,coils1 ,idle4 ,coils 9 a dynamo 9 :i* no electro-motive =ce is be+ g5]at$ or develop$4 ,coils t1 ?r\gh brok5 connections or %ort circuits1 are inactive4 ,column1 ,electric4 ,an old "n = ! voltaic pile4 ,! app>atus made up ( a pile ( disks ( copp] & z9c1 sep>at$ by pieces ( flannel wet ) acidulat$ wat]4 ,comb4 ,a b> f :i* a numb] ( tee? project l ! tee? ( a comb4 ,x is us$ z a collector ( electricity f ! plate ( a frictional electric ma*9e4 ,commutator4 ,an app>atus us$ on motors & dynamos & induction-coils = *ang+ ! direction ( curr5ts4 ,x is made 9 a v>iety ( types1 b usually 9 ! %ape ( insulat$ b>s closely pack$ ab\t an armature %aft4 ,commutator-b>s4 ,! metallic segm5ts ( a dynamo or motor-commutator4 ,commutators1 ,quiet4 ,commutators t d n sp>k dur+ ! revolutions ( ! armature4 ,compass4 ,an app>atus = indicat+ ! directive =ce ( ! e>? ^u ! magnetic ne$le4 ,x consi/s ( a case cov]$ ) glass1 9 :i* a magnetiz$ ne$le1 normally po9t+ to ! nor?1 is balanc$ on a po9t at ! c5tre4 ,"u ! ne$le a c>d is arrang$ on :i* ! degrees or po9ts ( ! compass are inscrib$4 ,a valuable in/rum5t 9 electrical "w1 magnetism1 etc4 ,compass1 ,liquid4 ,a =m ( m>9e compass4 ,! ne$le is atta*$ to a c>d or disk :i* floats 9 alcohol or o!r spirits1 s z to *eck undue oscillation4 ,compass1 ,m>9]s'4 ,a compass 9 :i* ! ne$le is atta*$ to a c>d t rotates 9 po9t+ to ! nor?4 ,a m>k1 call$ ! 8lubb]'s m>k10 is made ^u ! case1 & ?is is 9 l9e ) ! %ip's keel1 s t a glance at ! c>d w indicate ! direction 9 :i* ! %ip is head$4 ,compass1 ,_s4 ,a =m ( m>9]s' compass 9 :i* ! b[l1 or case1 is seal$ & fill$ ) alcohol4 ,! compass-c>d works z a sp9dle1 &1 by a s]ies ( air comp>tm5ts1 floats on ! alcohol4 ,! friction ( ! pivot is !reby greatly dim9i%$1 mak+ ! compass a v s5sitive "o4 ,compass1 ,/&>d4 ,a compass employ$ z a /&>d by :i* to comp>e o!r compasses4 ,cond5s]4 ,an appliance = /or+ up electro-/atic *>ges2 x is also call$ a /atic accumulator4 ,! telegraphic cond5s] consi/s ( a box pack$ full ( %eets ( t9-foil hav+ a %eet ( p>aff9$ pap] or %eet-mica betwe5 e two %eets4 ,! alt]nate %eets ( t9-foil are connect$ toge!r1 & ea* set has its b9d+-po/4 7,see also ,electro/atic ,accumulator47 ,cond5s]1 ,air4 7,see ,air-cond5s]47 ,cond5s]1 ,ayrton's4 7,see ,ayrton's ,cond5s]47 ,cond5s]-plate4 7,see ,plate1 ,cond5s]47 ,cond5s]1 ,slid+4 ,an app>atus 9 ! =m ( a ,leyd5-j> ^: coat+s c be slid pa/ ea* o!r to dim9i% or increase ! face area1 & also to dim9i% or increase ! capacity ( ! cond5s]4 ,conductance4 ,! conduct+ p[] ( a mass ( mat]ial1 v>y+ accord+ to its %ape & dim5sions4 ,! cyl9drical or r\nd conductor is ! be/ type = ! conveyance ( electric curr5ts4 ,conduction4 ,! transmission ( electricity ?r\gh an immobile m$ium1 su* z a wire1 or rod1 or a b>4 ,conductivity4 ,ability to conduct electric curr5ts4 ,! conductivity ( a wire is its p[] to conduct or transmit a curr5t4 ,glass has no conductivity1 & x is !re=e a non-conductor4 ,conductivity1 ,v>iable4 ,! *ange 9 ! conduct+ or transmitt+ p[]s ( metals & sub/ances "u diff]5t temp]atures4 ,hot metal conducts an electric curr5t bett] ?an cold4 ,a hot c>bon-p5cil 9 an arc-light conducts ! curr5t bett] ?an :5 ! light is fir/ />t$1 = z x w>ms up "u ! influ5ce ( ! arc-flame ! curr5t passes m freely4 ,five m9utes aft] ! curr5t is turn$ on ! lamps 9 ! circuit give a /eady light1 & d n sputt] z :5 !y fir/ />t up4 ,conductor4 ,any?+ :i* p]mits ! passage ( electric curr5t4 ,! t]m conductor is a relative "o1 &1 except+ a vacuum1 !re is probably no sub/ance t has n "s conductive p[]4 ,metals1 beg9n+ ) silv]1 are ! be/ conductors1 liquids next1 glass ! wor/4 ,! e!r1 or air1 is a conductor ( s\nd & electric vibratory di/urbances1 b n 9 ! same s5se z ! gr\nd4 ,! air conducts frictional electricity1 :ile ! gr\nd acts z a conductor = ! galvanic curr5t1 or 8curr5t electricity40 ,by ?is la/ t]m is meant electricity :i* fl[s cont9ually1 in/ead ( dis*>g+ all at once1 ) an accompany+ sp>k or fla%4 ,conductor1 ,ov]head4 ,ov]head electric l9es1 wires or cables1 = conduct+ curr5t4 ,g5]ally poles are erect$ = ?is purpose4 ,conductor1 ,prime4 ,a cyl9drical or sph]ical body ) no po9ts or angles1 b r\nd$ ev]y:]e & g5]ally ( metal4 ,if made ( o!r mat]ial1 su* z wood1 glass1 or composition1 its entire surface is r5d]$ conductive by be+ cov]$ ) %eet-metal1 su* z t9-foil1 gold-leaf or t9sel1 appli$ to x ) pa/e1 %ellac1 or glue4 ,a prime conductor %\ld be m\nt$ on an insulat$ /&2 x is employ$ to collect & reta9 frictional electricity g5]at$ by a /atic ma*9e4 ,conductor1 ,und]gr\nd4 ,an insulat$ conductor :i* is plac$ "u ! surface ( ! e>?1 pass+ ?r\gh conduits4 ,connect4 ,! act ( br++ two ends ( wire toge!r1 ei!r tempor>ily or p]man5tly4 ,br++ "o end ( a conductor into contact ) ano!r s z to e/abli% an electric connection4 ,connector4 ,a sleeve1 ) screws or o!r clamp+ device1 into :i* ! ends ( wires or rods may be pass$ & held securely4 ,a b9d+-po/ & spr+-jack comes "u ?is head4 ,contact4 ,! electrical union ( two conductors1 :e!r tempor>y or p]man5t4 ,x may be e/abli%$ by t\*+ ! ends or t]m9als ( a circuit ?r\gh ! ag5cy ( a pu%-button1 a telegraph-key1 an electric swit*1 etc4 ,contact-break]4 7,! same z ,circuit-break]1 :i* see47 ,contact1 ,loose4 ,a contact =m$ by two or sev]al surfaces impos$ "o ^u ano!r & held by _! weight alone4 ,contact-po9t4 ,a po9t1 or /ud1 (t5 ( silv] or plat9um1 arrang$ to come into t\* ) a contact-spr+1 su* z ! vibrat+ armature ( an electric bell4 ,contact-spr+4 ,a spr+ connect$ at "o end ( a lead & arrang$ to press aga9/ ano!r spr+ or plate1 s t a plug may be ins]t$ betwe5 ! contact-po9ts4 ,controll]4 ,! lev] or h&le on ! swit*-bo>d ( a resi/ance-coil1 by means ( :i* electric curr5t is let 9 or kept out ( a circuit4 ,controll+ ,=ce4 ,9 galvanomet]s & simil> in/rum5ts1 ! =ce us$ to br+ ! ne$le or indicator back to z]o4 ,conv]t]4 ,an induction-coil us$ ) ! alt]nat+ curr5t = *ang+ ! pot5tial diff]5ce & inv]t+ ! available curr5t4 ,high alt]nat+ voltage may be conv]t$ into l[] direct-curr5t voltage1 !reby increas+ ! amp]age or curr5t4 ,a conv]t] consi/s ( a core ( ?9 iron %eets1 w\nd ) a prim>y coil ( f9e insulat$ wire1 ) _m convolutions or turns4 ,also1 a second>y coil made up ( co>se insulat$ wire ) few] convolutions4 ,! coil may be jacket$ ) iron to increase ! p]man5ce4 ,conv]t]1 ,rot>y4 ,a comb9$ motor & dynamo ^: function is to trans=m a curr5t ( high or l[ voltage 7,a-,c41 or ,d-,c47 into any o!r k9d ( curr5t desir$4 ,convolution4 ,! /ate ( be+ convolv$2 a turn1 wrap1 fold1 or :orl4 ,a clock-spr+ is a famili> example4 ,copp]-ba?4 ,a solution ( sulphate ( copp] us$ 9 electro-plat+1 electrotyp+1 & copp]-ref9+ by electricity4 ,cord1 ,flexible4 ,a flexible-wire conductor made up ( _m /r&s ( f9e wire & prop]ly insulat$ s t x may be easily twi/$1 b5t1 or wrapp$4 ,flexible wire is us$ z ! conductors = portable electric lights1 pu%-buttons1 m$ical coils1 etc4 ,core4 ,! iron mass 7g5]ally locat$ 9 ! c5tre ( a coil or helix7 :i* becomes highly magnetic :5 a curr5t is fl[+ ar\nd x1 b :i* looses its magnetism imm$iately t ! curr5t ceases to fl[4 ,a conductor or ! conductors ( an electric cable made up ( a s+le /r& or _m /r&s laid toge!r & twi/$4 ,^! may be ( b>e metal1 or ea* "o insulat$ f ! o!rs4 ,core-disks4 ,disks ( ?9 wire1 = build+ up armature-cores4 ,! usual =m ( a core is r\nd or cyl9drical4 ,a numb] ( ?9 disks1 or lam9ations1 ( iron /rung ^u ! c5tral %aft1 & press$ firmly toge!r by ! end-nuts or keys4 ,?is arrangem5t gives a cyl9d] z a base on :i* to w9d ! insulat$ wire t =ms a "p ( ! armature4 ,core-disks1 ,pi]c$4 ,core-disks = an armature ( a motor or dynamo1 :i* h be5 pi]c$ or bor$ out ar\nd ! p]iph]y4 ,tubes ( insulat+ mat]ial1 su* z fibre1 rubb]1 or p>aff9$ pap]1 are ins]t$ 9 ! holes & ?r\gh ^! ! w9d+s ( wire are c>ri$4 ,! coils are ?us imb$d$ 9 ! solid mass ( iron1 & are protect$ f eddy curr5ts2 also !y act to r$uce ! reluctance ( ! air-gaps4 ,?is arrangem5t is v good1 f a me*anical po9t ( view1 b 9 practice its use is conf9$ to small motors only1 & dynamos g5]at+ "u "o hundr$ volts4 ,core-disks1 ,too!d4 ,core-disks ( an armature or motor :]e not*es are cut f ! p]iph]y4 ,:5 !y are lock$ toge!r1 to =m ! armature-core1 ! coils ( wire lie 9 ! grooves =m$ by a numb] ( ! disks b\nd toge!r4 ,?is con/ruction r$uces ! actual air-gaps & keeps ! coils equally spac$4 ,core1 ,lam9at$4 ,! core ( an armature1 an induction-coil1 a conv]t]1 or any simil> piece ( app>atus1 :i* is made up ( plates or disks1 insulat$ m or less p]fectly f "o ano!r by means ( mica or p>aff9$ pap]4 ,! object ( lam9ations is to prev5t ! =mation ( ,f\cault curr5ts4 ,a core built up ( disks is sometimes call$ a radially lam9at$ core4 ,core1 ,r+4 ,a dynamo or motor armature-core :i* =ms a complete r+4 ,core1 ,/r&$4 ,! core ( a cable1 or a conduct+ core made up ( a numb] ( sep>ate wires or /r&s laid or twi/$ toge!r4 ,core1 ,tubul>4 ,tubes us$ z cores = electro-magnets1 & also to produce small magnetiz+ p[]4 ,tubul> cores are ne>ly z effici5t z solid ones 9 /raight magnets1 because ! pr9cipal reluctance is due to ! air-pa?4 ,on increas+ ! curr5t1 h[ev]1 ! tubul> core becomes less effici5t4 ,c\lomb4 ,! practical unit ( electrical quantity4 ,x is ! quantity pass$ by a curr5t ( "o amp]e int5sity 9 "o second4 ,c\ple4 ,! comb9ation ( two electrodes & a liquid1 ! electrodes be+ imm]s$ 9 ! latt]1 & be+ act$ on diff]5tially by ! liquid4 ,?is comb9ation con/itutes a s\rce ( electro-motive =ce1 &1 consequ5tly ( curr5t1 & is call$ ! galvanic or voltaic cell or batt]y4 ,c\ple1 ,a/atic44 ,a t]m sometimes appli$ to a/atic ne$les :5 work+ 9 pairs4 ,c\pl+4 ,! union ( cells or g5]ators con/itut+ a batt]y2 ! volume ( curr5t1 or electro-motive =ce1 is !reby increas$4 ,c4 ,p4 ,an abbreviation = 8c&le p[]02 also mean+ 8*emically pure10 :5 speak+ ( *emicals4 ,crat]4 ,! depression t =ms 9 ! positive c>bon ( a voltaic-arc4 ,creep+4 ,a ph5om5a met ) 9 solution batt]ies4 ,! electrolyte creeps up ! sides ( ! conta9+ j> & evaporates1 leav+ a deposit ( salts4 ,/ill m solution creeps up ?r\gh ! salts until x gets cle> to ! top & runs ov]4 ,to prev5t ?is ! tops ( ! j>s %\ld be bru%$ ) hot p>aff9e = a di/ance ( two in*es f ! upp] edge4 ,! salts w n =m on p>aff9e4 ,oil is sometimes p\r$ on ! top ( ! batt]y solution1 b ?is affects ! elem5ts if x t\*es !m1 & makes _! surfaces non-conduct+4 ,crucible1 ,electric4 ,a crucible = melt+ refractory sub/ances1 or = r$uc+ ores by means ( ! electric arc produc$ )9 x4 ,probably ! result obta9$ is due m to curr5t inc&esc5ce ?an to ! action ( ! arc4 ,cry/allization1 ,electric4 ,"u prop] conditions _m sub/ances & liquids take a cry/all9e =m4 ,:5 su* action is br\ght ab\t by means ( electricity ! t]m electric cry/allization may be appli$ to ! ph5om5on4 ,a solution ( nitrate ( silv]1 :5 decompos$ by a curr5t1 w give cry/als ( metallic silv]4 ,a solution ( common salt or br9e1 :5 electrically decompos$1 w produce sodium & *lor9e4 ,! sodium appe>s at ! lead+-out electrode & readily unites ) c>bonic-acid gas1 :i* is inject$ into ! app>atus4 ,! result ( ! comb9ation is c>bonate ( soda1 "o ( ! mo/ important products ( ! alkali indu/ry4 ,curr5t1 ,alt]nat+4 ,a curr5t fl[+ alt]nately 9 opposite directions4 ,x is a succession ( curr5ts1 ea* ( %ort duration & ( direction opposite to t ( its pr$ecessor4 ,abbreviation1 ,a-,c4 ,curr5t1 ,amp]age4 ,! volume ( electricity pass+ ?r\gh any circuit p] second1 ! fl[ be+ uni=m4 ,curr5t1 ,con/ant4 ,an unv>y+ curr5t4 ,a con/ant-curr5t sy/em is "o 9 :i* ! curr5t is uni=mly ma9ta9$--= example1 9 electric light1 p[]1 & heat plants4 ,curr5t1 ,cont9u\s4 ,a curr5t ( "o direction only1 or ! rev]se ( an alt]nat+ curr5t4 ,curr5t1 ,direct4 ,a curr5t ( unv>y+ direction1 z di/+ui%$ f ! alt]nat+4 ,abbreviation1 ,d-,c4 ,curr5t ,di/ribution1 ,uni=m4 ,a /eady curr5t2 a curr5t ^: d5sity 9 a conductor is always ! same at all po9ts4 ,curr5t1 ,induc$4 ,a curr5t caus$ by electro-dynamic induction4 ,curr5t1 ,l[ ,pot5tial4 ,a curr5t ( l[ pressure4 ,a t]m appli$ to l[ electro-motive =ce4 ,curr5t1 ,make-&-break4 ,a curr5t :i* is cont9ually brok5 or int]rupt$ & />t$ aga94 ,! t]m is appli$ only :]e ! int]ruptions occur 9 rapid succession1 z 9 ! action ( an induction-coil or pole-*ang]4 ,! alt]nat+ curr5t4 ,curr5t-met]4 ,an app>atus = indicat+ ! /r5g? ( a curr5t1 su* z an ammet]4 ,curr5t1 ,oscillat+4 ,a curr5t p]iodically alt]nat+4 ,curr5t1 ,p]iodic4 ,a curr5t ) p]iodically v>y+ /r5g? or direction4 ,a curr5t alt]nat+ p]iodically4 ,curr5t1 ,pol>iz+4 ,a curr5t :i* causes pol>ization4 ,curr5t-rev]s]4 ,a swit* or o!r contrivance = rev]s+ ! direction ( a curr5t 9 a conductor4 ,curr5t1 ,undulat+4 ,a curr5t ^: direction is con/ant b ^: /r5g? is cont9u\sly v>y+4 ,curr5ts1 ,eddy4 ,useless curr5ts 9 an armature1 9 ! pole pieces1 & 9 ! magnetic cores ( dynamos & motors4 ,!y are creat$ by ! high spe$ ( ! armature 9 its rotation1 or by o!r electric curr5ts induc$ by ! armature's motion ?r\gh magnetic fields4 ,curr5ts1 ,f>adic4 ,induc$ curr5ts4 ,!y take _! "n f ,mi*ael ,f>aday1 ! orig9al inve/igator ( ! ph5om5a ( electro-magnetic induction4 ,! second>y or induc$ electro-magnetic curr5ts & _! accompany+ ph5om5a4 ,a s]ies ( alt]nat+ electro-/atic dis*>ges f influ5ce ma*9e1 su* z ! ,holtz & ,wim%ur/4 ,! simple & commonly und]/ood ,f>adic curr5ts are ^? produc$ 9 ! m$ical batt]y1 & us$ 9 m$ical !rapeutics4 ,curr5ts1 ,f\cault4 ,a =m ( curr5ts produc$ 9 revolv+ armature-cores2 sometimes call$ eddy curr5ts4 ,!y are useless4 ,curr5ts1 ,h>monic4 ,curr5ts :i* alt]nate p]iodically1 & v>y h>monically4 ,curr5ts :i* vibrate at c]ta9 pit*es1 z1 = in/ance1 ! curr5ts 9 wireless telegraphy4 ,two in/rum5ts mu/ be tun$ to ! same pit* 9 ord] to be responsive4 ,?us an in/rum5t s5d+ out waves ( #gj1jjj vibrations _c be record$ by "o tun$ mu* bel[ or above ! same numb]4 ,s\nd waves ( sympa!tic or h>monic vibrations4 ,curr5ts1 ,positive4 7,see ,positive ,curr5ts47 ,cut-94 ,to electrically connect a piece ( me*anism or a conductor ) a circuit4 ,cut-out4 ,! rev]se ( ! cut-94 ,to remove f a circuit any conduct+ device4 ,! cut-out may be s arrang$ z to leave ! circuit complete 9 "s o!r way4 ,an appliance = remov+ a piece ( app>atus f a circuit s t no m curr5t %all pass ?r\gh ! =m]4 ,cut-out1 ,automatic4 ,a safety device = automatically cutt+ out a circuit to prev5t accid5t or ! burn+-out ( an app>atus1 due to an ov]load ( curr5t4 ,x is work$ by an electro-magnet & spr+4 ,an ov]load ( curr5t causes a magnet ( high resi/ance to draw an armature t[>ds x1 & ?is1 9 turn1 releases ! spr+ ( ! cut-out device4 ,sometimes a /rip or wire ( fusible metal is employ$ :i* is 9 circuit ) a swit*4 ,! excess ( curr5t fuses ! metal1 & ! brok5 circuit releases a spr+-jack1 :i*1 9 turn1 breaks ! circuit4 ,cut-out1 ,safety4 ,a block ( non-conduct+ mat]ial1 su* z m>ble1 slate1 or porcela91 c>ry+ a safety-fuse or plugs4 ,9 ^! is enclos$ a piece ( fusible wire1 :i* burns out or melts & breaks ! circuit be=e ! app>atus is damag$4 ,cut-out1 ,w$ge4 ,a cut-out op]at$ by a w$ge1 su* z a spr+-jack or ! plugs at ! end ( ! flexible wires on ! swit*-bo>ds ( telephone ex*anges4 ,d ,damp]4 ,a frame ( copp] on :i* ! wire 9 a galvanomet] is sometimes coil$4 ,x acts to *eck ! ne$le oscillations4 ,a brass or copp] %ea?+ or tube plac$ betwe5 ! prim>y & second>y coils ( an induction-coil to cut (f induction & dim9i% ! curr5t & pot5tial ( ! second>y circuit4 ,:5 ! tube is drawn out gradually ! induction increases4 ,x is commonly us$ 9 m$ical coils to adju/ _! /r5g? ( action4 ,d-,c4 ,an abbreviation = direct curr5t4 ,dead ,e>?4 ,a fault 9 telegraph & telephone l9es :i* consi/s 9 ! gr\nd-wire be+ improp]ly gr\nd$1 or n fully connect$ ) ! e>?4 ,dead ,turns4 ,a t]m appli$ to ! t5 to tw5ty p] c5t4 ( ! convolutions or turns ( wire on an armature :i* are consid]$ to be dead4 ,!re are suppos$ to be ab\t eighty p] c5t4 ( ! turns on an armature t are active 9 magnetiz+ ! core2 ! balance are outside ! magnetic field & are t]m$ dead1 al?\gh !y are necess>y to ! production ( electro-motive =ce4 ,dead ,wire4 ,a wire 9 ! electric circuit ?r\gh :i* no curr5t is pass+4 ,a disus$ or ab&on$ electric conductor1 su* z a telegraph wire1 or a wire :i* may be 9 circuit1 b ?r\gh :i* at ! "t ( speak+ no electrical action is tak+ place4 ,dea?1 ,electrical4 ,dea? result+ f an electric curr5t pass+ ?r\gh ! animal body--electrocution2 accid5tal dea? by electric %ock2 prem$itat$ dea? ?r\gh br++ ! body 9 direct contact ) conductors c>ry+ high electro-motive =ce4 ,high electro-motive =ce is ess5tial1 & ! alt]nat+ curr5t is mo/ fatal4 ,decomposition1 ,electrolytic4 ,! decomposition or sep>ation ( a comp\nd liquid into its con/itu5ts by electrolysis4 ,! liquid mu/ be a conductor or electrolyte1 & ! decomposition is c>ri$ on by means ( electricity4 ,! conv]sion ( two or m *emicals into a new comp\nd or sub/ance4 ,deflection4 ,9 magnetism1 ! movem5t ( ! ne$le out ( ! plane4 ,x is due to di/urbance1 or to ! ne$le's attraction t[>ds a mass ( iron or /eel or ano!r magnet4 ,demagnetization4 ,! removal ( magnetism f a p>amagnetic sub/ance4 ,! process is pr9cipally 9 use = wat*es :i* h become magnetiz$ by exposure to ! magnetic field surr\nd+ dynamos or motors4 ,d5sity1 ,electric4 ,! relative quantity ( electricity1 z a *>ge1 ^u a unit area ( surface4 ,x may be positive or negative4 ,surface d5sity1 z ! *>ge ( a ,leyd5-j>4 ,depol>ization4 ,a t]m appli$ to ! removal ( p]man5t magnetism1 su* z t f a horse%oe magnet1 a wat*1 or a b>-magnet4 ,heat is ! common depol>iz]1 b c\nt] electro-magnetic =ces are employ$ also 9 ! v>i\s =ms ( app>atus kn[n z demagnetiz]s4 ,deposit1 ,electrolytic4 ,! metal or o!r sub/ances precipitat$ by ! action ( a batt]y or o!r curr5t-g5]ator1 z 9 ! plat+ processes4 ,detector4 ,a portable galvanomet]1 by means ( :i* a curr5t & its approximate /r5g? c be detect$ & measur$4 ,diaphragm4 ,9 telephones & microphones1 a disk ( iron ?r[n into motion by s\nd-waves or by electric impulse4 ,x is usually a ?9 plate ( japann$ iron1 su* z is us$ 9 ! f]rotype photographic process = mak+ t9-types4 ,dielectric4 ,any sub/ance ?r\gh :i* electro/atic induction is all[$ to occur1 su* z glass or rubb]4 ,x is a non-conductor = all electric curr5ts4 ,dielectric ,resi/ance4 ,! resi/ance a body (f]s to p]=ation or de/ruction by an electric dis*>ge4 ,dimm]4 ,an adju/able *oke or resi/ance coil us$ = regulat+ ! int5sity ( electric inc&esc5t lamps4 ,x is employ$ ext5sively 9 !atres = rais+ or l[]+ ! brilliancy ( lights4 ,dipp+4 ,! process ( clean+ articles by dipp+ !m 9 acids or cau/ic soda1 prep>atory to electro-plat+4 ,simple imm]sion1 ) or )\t curr5t1 to put a blu% ( metal on a clean$ surface4 ,dipp+-ne$le4 ,a magnetic ne$le m\nt$ on a horizontal be>+ s t x w dip v]tically :5 excit$ by a curr5t pass+ horizontally ab\t x4 ,! ord9>y compass-ne$le is m\nt$ on a po9t1 & sw+s freely to ! "r or left only4 ,direct ,curr5t4 7,see ,curr5t1 ,direct47 ,dis*>ge4 ,! eruptive dis*>ge f a ,leyd5-j> or accumulator ( a volume ( electricity /or$ )9 x4 ,! ab/raction ( a *>ge f a conductor by connect+ x to ! e>? or to ano!r conductor4 ,dis*>ge1 ,disruptive4 ,! dis*>ge ( a /atic *>ge ?r\gh a dielectric4 ,x involves ! me*anical p]=ation ( ! dielectric4 ,disconnect4 ,to break an electric circuit or op5 x s z to /op ! fl[ ( curr5t2 to remove a "p ( a circuit or a piece ( app>atus f a circuit4 ,di/illation1 ,electric4 ,! di/ill+ ( a liquid by ! employm5t ( electricity1 :i*1 by electrify+ ! liquid1 assi/s ! effects ( heat4 ,x is ass]t$ t ! process is accel]at$ by ! electrification ( ! liquid or fluid1 b x mu/ be a conductor liquid or electrolyte4 ,oil1 be+ a non-conductor1 is n affect$ by any electric curr5t1 no matt] :at its specific gravity may be4 ,di/ribut+ ,c5tre4 ,! c5tre ( di/ribution 9 a sy/em hav+ bran* circuits1 su* z ! electric-light or telephone outlets f a ma9 /ation4 ,door-op5]1 ,electric4 ,a magnetic contrivance arrang$ 9 connection ) a lock1 by means ( :i* ! lat* is releas$ by press+ a di/ant pu%-button4 ,?is device is us$ 9 flats & ap>tm5t-h\ses = op5+ a door f any ( ! ap>tm5ts 9 ! h\se4 ,d\ble ,filam5t ,lamp4 ,an inc&esc5t lamp hav+ two filam5ts1 "o ) a high capacity1 ! o!r ) a l[ "o4 ,! high capacity may be f sixte5 to fifty c&le-p[]1 ! o!r f "o to five4 ,a turn ( ! bulb 9 its socket1 or ! pull+ ( a /r+ :i* op]ates a swit* 9 ! socket1 cuts out ! curr5t f ! long filam5t & s5ds x ?r\gh ! %ort] & f9] "o1 ?us giv+ a weak] light4 ,^! 8hy-lo0 lamps are useful z night lamps 9 halls1 ba?-rooms1 or 9 sick-rooms1 :]e a l[ or weak light is requir$ all night4 ,d\ble ,pole-swit*4 ,a cut-out t is arrang$ to cut out ! circuit ( bo? ! negative & positive leads at ! same "t4 ,d\ble-pu%4 ,a contact-pu% hav+ two contacts & arrang$ s t pressure ^u x op5s "o contact & closes ! o!r4 ,d\ble ,?r[-swit*4 ,a swit* s arrang$ t x c be ?r[n into ei!r "o ( two contacts2 a ?r[-ov] swit*4 ,driv+-pulley4 ,! broad-fac$ or *annell$ pulley on an armature %aft by means ( :i* ! p[] f a motor may be transmitt$ me*anically4 ,dry ,batt]y4 7,see ,batt]y1 ,dry47 ,duct4 ,! space 9 an und]gr\nd conduit = a s+le wire or cable4 ,duplex ,wire4 ,an insulat$ conductor hav+ two di/9ct wires twi/$ or laid toge!r1 b prop]ly insulat$ f ea* o!r4 ,dynamic ,electricity4 ,electricity 9 motion or fl[+1 z di/+ui%$ f /atic or frictional electricity4 ,electricity ( relatively l[ pot5tial or electro-motive =ce 9 l>ge quantity or amp]age4 ,dynamo4 ,an app>atus consi/+ ( a core & field-magnets1 prop]ly w\nd ) insulat$ wire1 :i*1 :5 put into op]ation by revolv+ ! core or armature at high spe$1 develops electric curr5t2 a me*anical g5]ator ( electricity4 ,dynamo1 ,motor4 7,see ,motor-dynamo47 ,e ,e>?4 ,! accid5tal gr\nd+ ( a circuit is t]m$ an 8e>?40 ,e>?-plate4 ,a plate buri$ 9 ! gr\nd to receive ! ends ( telegraph l9es & o!r circuits1 & s give a gr\nd connection4 ,copp] plates are (t5 us$1 b 9 h\ses ! gr\nd is usually =m$ by atta*+ a wire to ! gas or wat] pipes4 ,e>? ,return4 ,! gr\nd+ ( a wire 9 a circuit at bo? ends gives ! circuit an e>? return4 ,?is me?od is commonly us$ 9 telegraph l9es1 bo? 9 ! wire & wireless sy/ems4 ,eddy ,curr5ts4 7,see ,curr5ts1 ,eddy47 ,edison ,di/ribut+-box4 ,a box us$ 9 ! ,edison 8?ree-wire0 sy/em1 f :i* ! outlets pass to local circuits4 ,edison ,lal&e ,cell4 ,a z9c-copp] batt]y hav+ a depol>iz+ coat+ ( copp] oxide on ! copp] elem5t1 ! c\ple be+ imm]s$ 9 an electrolyte compos$ ( pota% or cau/ic soda4 ,ediswan4 ,a t]m appli$ to ! inc&esc5t lamps inv5t$ by ,edison & ,swan & us$ ext5sively 9 ,great ,brita94 ,also appli$ to o!r app>atus design$ by ! two inv5tors4 ,effici5cy4 ,! relation ( "w done to ! electrical en]gy absorb$4 ,! effici5cy is n equal to ! en]gy absorb$1 because x always takes m p[] to g5]ate a curr5t ?an is giv5 back 9 actual effici5cy4 ,?is is due to me*anical friction & to ! resi/ance ( ! air 9 a me*anism su* z a dynamo :5 revolv+ at high spe$4 ,effici5cy1 ,electrical4 ,9 a g5]ator x is ! total electrical en]gy produc$1 bo? t wa/$ & t actually us$ 9 driv+ ma*9]y or app>atus4 ,effloresc5ce4 ,! dry salts on a j> or vessel conta9+ liquid t collects above ! wat] or evaporation l9e4 ,?is is due to creep+4 ,ela/icity4 ,a prop]ty 9 "s bodies & =ces ?r\gh :i* !y recov] _! =m] figure1 %ape1 or dim5sions :5 ! ext]nal pressure or /ress is remov$4 ,wat] has no ela/icity4 ,air is v ela/ic2 /eam has a great volume ( ela/icity2 :ile electricity is und\bt$ly ! mo/ ela/ic ( all 9 its motion ?r\gh air1 wat]1 & o!r conduct+ m$iums4 ,electric4 ,p]ta9+ to electricity2 any?+ connect$ ) ! use ( electricity4 ,x has be5 a mu*-abus$ ^w1 & its mean+ has be5 g>bl$ by ! impo/or1 ! crook1 & ! 8bus9ess ?ief0 9 foi/+ on ! public w>es 9 :i* !re 0 no electrical prop]ty :atev]4 8,electric0 too?bru%es1 combs1 corsets1 belts1 & ! l may conta9 a few bits ( magnetiz$ /eel1 b !y possess no active !rapeutic value4 ,electrical ,eng9e]4 ,! pr(ession ( electrical eng9e] calls = ! highe/ k ( electricity1 bo? !oretical & practical4 ,x embraces ! design+ & in/allation ( all k9ds ( electrical app>atus4 ,electrician4 ,"o v]s$ 9 ! practices & sci5ce ( electricity2 a practical l9eman or wireman4 ,electricity4 ,"o ( ! hidd5 & my/]i\s p[]s ( nature1 :i* man has br\ght "u control to s]ve 8 ends1 & :i* manife/s itself ma9ly ?r\gh attraction & repulsion2 ! mo/ p[]ful & yet ! mo/ docile =ce kn[n to man1 com+ f n[h]e & )\t =m1 weight1 or color1 invisible & inaudible2 an en]gy :i* fills ! univ]se & :i* is ! active pr9ciple 9 heat1 light1 magnetism1 *emical aff9ity1 & me*anical motion4 ,electricity1 ,atmosph]ic4 ,! electric curr5ts ( ! atmosph]e1 v>iable b nev] abs5t4 ,!y include lightn+1 frictional electricity1 ! ,aurora ,borealis1 ! electric waves us$ 9 wireless telegraphy1 etc4 ,b5jam9 ,frankl9 indicat$ ! me?od ( draw+ electricity f ! cl\ds4 ,9 ,june1 #ageb1 he flew a kite1 & by its moi/5$ cord drew an electric curr5t f ! cl\ds s t sp>ks 7 visible on a brass key at ! gr\nd end ( ! cord4 ,lat]1 :5 a f9e wire 0 sub/itut$ = ! cord1 & a kite 0 fl[n 9 a ?und]-/orm1 ! electric sp>k 0 vivid4 ,?is exp]im5t confirm$ 8 hypo!sis t lightn+ 0 id5tical ) ! disruptive dis*>ges ( electricity4 ,electricity1 ,lat5t4 ,! b\nd *>ge ( /atic electricity4 ,electricity1 ,negative4 7,see ,negative ,electricity47 ,electricity1 ,positive4 7,see ,positive ,electricity47 ,electricity1 ,voltaic4 ,electricity ( l[ pot5tial diff]5ce & l>ge curr5t int5sity4 ,electricity produc$ by a voltaic batt]y or dynamo z oppos$ to /atic electricity1 :i* is frictional & practically uncontrollable = comm]cial purposes4 ,electrification4 ,! process ( imp>t+ an electric *>ge to a surface4 ,! t]m is appli$ *iefly to electro-/atic ph5om5a4 ,electrization4 ,9 electro-!rapeutics1 ! subjection ( ! human sy/em to electric treatm5t4 ,an electric tonic imp>t$ by electro-m$ical ba?s ?r\gh ! n]v\s sy/em4 ,electro-*emi/ry4 ,t bran* ( sci5ce :i* treats ( ! relations betwe5 electric & *emical =ces 9 _! diff]5t reactions & comp\nds4 ,x deals ) electro-plat+1 electro-fus+1 electrolysis1 etc4 ,electro-culture4 ,! application ( electricity to ! cultivation ( plants4 ,! use ( electricity has be5 f\nd v b5eficial 9 "s =ms ( plant gr[?4 ,electrocution4 ,capital puni%m5t inflict$ by electric curr5t f a dynamo ( high electro-motive =ce4 ,! curr5t us$ is f #aejj to #bjjj volts1 & x acts to break d[n ! tissues ( ! body4 ,electrode4 ,! t]m9als ( an op5 electric circuit4 ,! t]m9als betwe5 :i* an electric arc is =m$1 z 9 ! arc-light4 ,! t]m9als ( ! conductors ( an electric circuit imm]s$ 9 an electrolytic solution1 su* z ! c>bon & z9c ( a batt]y4 ,electroli]4 ,a fixture = support+ electric lamps1 simil> to a *&eli] = gas or c&les4 ,comb9ation electroli]s conduct bo? gas & electricity4 ,electrolysis4 ,! sep>ation ( a *emical comp\nd into its con/itut$ p>ts by ! action ( an electric curr5t4 ,electrolyte4 ,a body susceptible ( decomposition by ! electric curr5t4 ,x mu/ be a fluid body & a conductor capable ( diffusion z well z composite 9 its make-up4 ,an elem5tal body su* z pure wat] _c be an electrolyte4 ,electrolytic ,decomposition4 7,see ,decomposition1 ,electrolytic47 ,electrolytic ,deposit4 7,see ,deposit1 ,electrolytic47 ,electrolytic ,resi/ance4 7,see ,resi/ance1 ,electrolytic47 ,electro-magnetic ,induction4 7,see ,induction1 ,electro-,magnetic47 ,electro-magnetism4 ,magnetism creat$ by electric curr5t4 ,t bran* ( electrical sci5ce :i* treats ( ! magnetic relations ( a field ( =ce produc$ by a curr5t4 ,electro-m$ical ,ba?4 ,a ba? provid$ ) connections & electrodes = caus+ a curr5t ( electricity to pass ?r\gh ! body ( ! pati5t4 ,electromet]4 ,an in/rum5t us$ = measur+ /atic electricity4 ,electromet]s are diff]5t f galvanomet]s1 s9ce ! latt] dep5d on a curr5t fl[+ ?r\gh wires to create an action ( ! magnetic ne$les4 ,electro-motive ,=ce4 ,voltage4 ,x may be comp>$ to ! pressure ( wat] 9 hydraulic sy/ems4 ,! unit ( electro-motive =ce is ! volt4 ,electro-motor4 ,a t]m sometimes appli$ to a curr5t-g5]ator1 su* z a small dynamo or voltaic batt]y4 ,electro-plat+4 7,see ,plat+1 ,electro47 ,electropoion ,fluid4 ,an acid depol>iz+ solution = use 9 z9c-c>bon c\ples1 su* z ! 8,gr5et0 & 8,daniell0 cells4 ,! bi-*romate-(-pota% & sulphuric-acid solution = batt]y *>ges is a good example4 ,electroscope4 ,an app>atus = indicat+ ! pres5ce ( an electric *>ge & :e!r ! *>ge is negative or positive4 ,electro/atic ,accumulator4 ,two conduct+ surfaces1 sep>at$ by a dielectric & arrang$ = ! opposite *>g+ ( ! two surfaces4 ,a f>adic or /atic ma*9e = accumulat+ frictional electricity is an example4 ,electro/atics4 ,t division ( electric sci5ce :i* treats ( ! ph5om5a ( ! electric *>ge1 or ( electricity 9 repose1 z contra/$ ) electro-dynamics or electricity 9 motion4 ,electrotype4 ,! reproduction ( a =m ( type or engrav+ by ! copp] electro-plat+ process4 ,! orig9al is coat$ ) plumbago & a wax impression tak5 ( x4 ,! face ( ! negative is made conductive ) plumbago or t9 du/1 !n susp5d$ 9 a copp] ba? & connect$ ) ! curr5t4 ,a film ( copp] w be deposit$ on ! face ( ! wax impression4 ,elem5t1 ,*emical4 ,orig9al =ms ( matt] t _c be sep>at$ into simple con/itu5ts by any kn[n process4 ,!re are ab\t sev5ty 9 all1 b z sci5ce advances ! li/ is con/antly be+ revis$4 ,new elem5ts are discov]$ & kn[n ones are be+ resolv$ into simpl] =ms4 ,elem5ts ( ,batt]y ,cell4 7,see ,batt]y ,cell1 ,elem5ts (47 ,em]g5cy ,swit*4 ,an auxili>y swit* us$ z a controll] on a c> to rev]se ! action ( ! motor4 ,e-,m-,f4 ,an abbreviation = electro-motive =ce1 or voltage4 ,equaliz]4 ,a t]m appli$ to a wire or b> 9 electro-magnetic me*anism = equaliz+ ! pressure ov] a sy/em4 ,excit]4 ,a g5]ator us$ = excit+ ! field-magnets ( a dynamo4 ,ext5sion ,call-bell4 ,a bell connect$ ) a telephone call-bell1 & locat$ 9 ano!r "p ( a build+ s z to give a di/ant summons4 ,ext]nal ,circuit4 7,see ,circuit1 ,ext]nal47 ,f ,f4 ,! sign commonly employ$ to designate ,fahr5heit4 ,?us1 #cj ,f4 means #cj degrees ,fahr5heit1 or #cj degrees above z]o4 ,false ,magnetic ,poles4 7,see ,magnetic ,poles1 ,false47 ,f>adic4 ,induc$ curr5t produc$ f induction-coils & f>adic ma*9es4 ,a s]ies ( alt]nat+ electro/atic dis*>ges1 z f a ,holtz influ5ce ma*9e4 ,f>adic ,coil4 7,see ,coil1 ,f>adic47 ,f>adic ,curr5ts4 7,see ,curr5ts1 ,f>adic47 ,f>adic ,ma*9e4 ,an app>atus design$ to produce f>adic curr5t4 ,fe$4 ,to furni% an electric curr5t1 also spok5 ( 9 connection ) ! me*anism t moves ! c>bons 9 arc-lamps4 ,fe$]s1 or ,fe$ ,wires4 ,! conductors :i* convey electric curr5ts at diff]5t po9ts1 z 9 ! trolley sy/em4 ,! curr5t is c>ri$ along 9 l>ge cables /rung on poles or laid und]gr\nd1 & at prop] di/ances l9es are run 9 to fe$ ! trolley wire4 ,field4 ,! space 9 ! neighborhood ( a dynamo or motor1 or o!r g5]ator ( electric curr5t1 f :i* ! app>atus takes its electricity1 bo? electro/atic & magnetic4 ,field-magnet4 7,see ,magnet1 ,field47 ,field ( ,=ce4 ,! space 9 ! neighborhood ( an attract+ or repell+ mass or sy/em4 ,!re are two k9ds ( fields ( =ce--! electro-magnetic & ! /atic--f :i* ! respective pieces ( app>atus draw _! /ore ( electricity4 ,filam5t4 ,a long1 ?9 piece ( solid sub/ance4 ,x is g5]ally z ?9 z a ?read & flexible en\gh to be b5t4 ,! hairlike elem5t 9 an inc&esc5t lamp :i*1 :5 heat$ by a curr5t1 gl[s & radiates light4 ,filam5ts1 ,pap]4 ,filam5ts = inc&esc5t lamps made ( c>boniz$ pap]4 ,!y 7 ! ones orig9ally us$ 9 electric lamps1 b h be5 sup]s$$ by o!r sub/ances easi] to h&le & m durable4 ,fl[4 ,! volume ( a curr5t or /ream escap+ ?r\gh a conductor1 su* z a wire1 rod or pipe4 ,fluoresc5ce4 ,! prop]ty ( conv]t+ e!r waves ( "o l5g? into waves ( ano!r l5g?4 ,! ph5om5on is utiliz$ 9 ! production ( ,geissl] tubes & ,x-rays4 ,fluoroscope4 ,an app>atus = mak+ exam9ations by means ( ! ,x-rays4 ,fluoroscopic ,scre54 ,a scre5 ov]spread ) fluoresc5t mat]ial & employ$ = fluoroscopic exam9ations 9 connection ) ! ,x-rays4 ,=ce4 ,any *ange 9 ! condition ( matt] ) respect to motion or re/4 ,=ce is measur$ by ! accel]ation or *ange ( motion t x c imp>t to a body ( a unit mass 9 a unit ( "t4 ,= in/ance1 t5 p\nds pressure ( /eam w be indicat$ on a gauge made = measur+ /eam4 ,t pressure ( /eam1 ) ! prop] volume beh9d x1 is capable ( in/antly produc+ a giv5 "p ( a horse-p[]4 ,9 ! same way t5 volts ( electro-motive =ce is capable ( pu%+ a curr5t s z to ex]t a c]ta9 fraction ( horse-p[]4 ,=ce1 ,electro-magnetic4 ,! =ce ( attraction or repulsion ex]t$ by ! electro-magnet4 ,x is also kn[n z electric =ce 9 ! electro-magnetic sy/em4 ,f\cault ,curr5ts4 7,see ,curr5ts1 ,f\cault47 ,fractional ,di/illation4 ,! process ( evaporat+ liquids by heat1 ! mo/ volatile be+ ! fir/ treat$4 ,:5 t has be5 evaporat$ & di/ill$ ! heat is rais$ & ! next mo/ volatile liquid is evaporat$1 & s on until all are evaporat$1 leav+ z a residue ! solids t 7 a "p ( ! orig9al mass ( liquid4 ,friction4 ,! effect ( rubb+1 or ! resi/ance :i* a mov+ body enc\nt]s :5 9 contact ) ano!r body4 ,frictional ,electric ,ma*9e4 ,an app>atus = ! developm5t or g5]ation ( high-t5sion frictional electricity4 ,frictional ,electricity4 ,electricity produc$ by ! friction ( dissimil> sub/ances4 ,full ,load4 ,a complete load4 ,! greate/ load a ma*9e or second>y batt]y w c>ry p]man5tly4 ,! full capacity ( a motor runn+ at its regi/]$ spe$ = its horse-p[]4 ,furnace1 ,electric4 ,a furnace 9 :i* ! heat is produc$ by ! electric arc4 ,x is ! hotte/ furnace kn[n to man1 & temp]atures z high z #gejj ,fahr5heit h be5 develop$ 9 x4 ,fuse1 ,electric4 ,a fuse = ignit+ an explosive *>ge by electricity4 ,x is made by br++ ! t]m9als or ends ( wires close toge!r1 s t !y w sp>k :5 a curr5t passes ?r\gh !m4 ,or a ?9 piece ( highly resi/ant wire may be imb$d$ 9 an explosive & br\ght to :ite heat by curr5t4 ,fuse-block4 ,an insulator hav+ a safety-fuse made fa/ to x4 ,fuse-box4 ,a box conta9+ a safety-fuse1 g5]ally ( porcela91 enamell$ iron1 or "s o!r non-conductor4 ,fuse-l9ks4 ,l9ks compos$ ( /rips or plates ( fusible metal s]v+ ! purpose ( safety-fuses4 ,fus+-curr5t4 ,a curr5t ( suffici5t /r5g? to cause ! bl[+ or fus+ ( a metal4 ,g ,galvanic4 ,voltaic4 ,relat+ to curr5t electricity or ! electro-*emical relations ( metals4 ,galvanic ,ta/e4 ,a salty ta/e 9 ! m\? result+ f ! passage ( a light curr5t f a voltaic batt]y1 ! ends ( ! wires be+ held to ei!r side ( ! tongue4 ,?is has be5 call$ ta/+ electricity1 b x is really ! decomposition ( saliva on ! surface ( ! tongue1 due to electrolysis or ! passage ( a curr5t ?r\gh a liquid4 ,galvanism4 ,! sci5ce ( voltaic1 or curr5t1 electricity4 ,galvaniz+4 ,coat+ iron ) a ?9 lay] ( z9c by imm]s+ ! object 9 ! molt5 metal4 ,galvano-f>adic4 ,9 m$ical electricity ! %ock+-coil4 ,! application ( ! voltaic curr5t1 induc$ by a second>y curr5t 7induction-coil71 to any "p ( ! body4 ,galvanomet]4 ,an in/rum5t = measur+ curr5t /r5g?4 ,a magnetic ne$le influ5c$ by ! passage ( a curr5t ?r\gh a wire or coil locat$ ne> x4 ,galvanomet]1 ,tang5t4 ,a galvanomet] provid$ ) two magnetic ne$les diff]+ 9 l5g?1 ! %ort] "o s]v+ to measure tang5ts1 ! long] be+ us$ = s9e measurem5ts ( curr5t /r5g?4 ,galvanoscope4 ,an in/rum5t1 g5]ally ( ! galvanomet] type1 us$ to asc]ta9 :e!r a curr5t is fl[+ or n4 ,g5]ator4 ,an app>atus = ma9ta9+ an electric curr5t1 su* z a dynamo1 a f>adic ma*9e1 a batt]y1 etc4 ,g]man-silv]4 ,an alloy ( copp]1 nickel1 & z9c4 ,us$ *iefly 9 resi/ance-coils1 ei!r 9 ! =m ( wire or 9 /rips ( ! %eet-metal4 ,gold-ba?4 ,a solution ( gold us$ = deposit+ t metal 9 ! electro-plat+ ba?4 ,graphite4 ,a =m ( c>bon4 ,x occurs 9 nature z a m9]al1 & also is made artificially by ! ag5cy ( electric heat4 ,gravity ,batt]y4 7,see ,batt]y1 ,gravity47 ,gr\nd$ ,circuit4 7,see ,circuit1 ,gr\nd$47 ,gr\nd-plate4 7,see ,plate1 ,gr\nd47 ,gr\nd-wire4 ,! contact ( a conductor1 9 an electric circuit1 ) ! e>?4 ,x p]mits ! escape ( curr5t if ano!r gr\nd-wire exi/s4 ,gu>d ,tube4 ,a tube ins]t$ 9 a wood5 or brick p>tition to insulate wires t may pass ?r\gh x4 ,^! tubes are made ( porcela91 gutta-p]*a1 compositions ( a non-conduct+ nature1 & fibre4 ,gutta-p]*a4 ,ca\t*\c treat$ ) sulphur to h>d5 x2 sometimes call$ vulcaniz$ rubb] or vulcanite4 ,x is a product obta9$ f tropical trees1 & :5 prop]ly treat$ x is a valuable insulator 9 electrical "w1 p>ticul>ly 9 subm>9e cables1 s9ce x (f]s great resi/ance to ! de/ructive ag5cies ( ! ocean's dep?s4 ,h ,h& ,g5]ator4 ,a magneto-g5]ator driv5 by h& = ! g5]ation ( light curr5ts4 ,h>monic ,curr5ts4 7,see ,curr5ts1 ,h>monic47 ,h>monic ,receiv]4 ,a receiv] conta9+ a vibrat+ re$ act$ on by an electro-magnet4 ,su* a re$ answ]s only to impulses tun$ to its pit*4 ,heat4 ,"o ( ! =ce ag5ts ( nature4 ,x is recogniz$ 9 its effects ?r\gh expansion1 fusion1 evaporation1 & g5]ation ( en]gy4 ,heat1 ,electric4 ,caus$ by a resi/+ m$ium1 su* z c>bon or ,g]man-silv]1 :5 too mu* curr5t is =c$ ?r\gh x4 ,! pr9ciple ( ! c>-w>m]s1 electric iron1 electric *af+-di%1 etc4 ,helix4 ,a coil ( wire4 ,prop]ly a coil ( wire s w\nd z to foll[ ! outl9es ( a screw )\t ov]lay+ itself4 ,horse-p[]1 ,electric4 ,mean+ ! same z 9 me*anics4 ,ref]r$ to :5 speak+ ( ! work+ capacity ( a motor or ! p[] requir$ to drive a dynamo4 ,horse-p[] ,h\r4 ,a unit or /&>d ( electrical "w !oretically equal to t accompli%$ by "o horse dur+ "o h\r4 ,horse%oe ,magnet4 7,see ,magnet1 ,horse%oe47 ,h-,p4 ,abbreviation = horse-p[]4 ,hydromet]4 ,an in/rum5t employ$ to det]m9e ! am\nt ( moi/ure 9 ! atmosph]e4 ,an in/rum5t = det]m9+ ?r\gh flotation ! d5sity or specific gravity ( liquids & fluids4 ,x consi/s ( a weight$ glass bulb or holl[ metallic cyl9d] ) a long /em on :i* ! ,baum scale is m>k$4 ,dropp+ x into a liquid x floats 9 a v]tical position1 & s9ks to a level consi/5t ) ! gravity ( ! fluid4 ,hydromet]1 ,baum4 ,an app>atus = te/+ ! gravity ( fluids4 ,! z]o po9t corresponds to ! specific gravity ( wat] = liquids heavi] ?an wat]4 ,a gauge1 valuable 9 te/+ acids & o!r fluids us$ 9 electrical "w4 ,i ,ignit]4 ,a me*anical h& app>atus1 9 :i* a batt]y1 induction-coil1 & vibrator are locat$1 & ^: sp>k1 jump+ across a gap at ! end ( a rod1 ignites or lights a gas flame1 bla/+-p[d]1 or dynamite4 ,i-,h-,p4 ,an abbreviation = indicat$ horse-p[]4 ,illum9at+ ,p[]4 ,any s\rce ( light z comp>$ ) a /&>d light--z1 = in/ance1 ! illum9at+ p[] ( an electric light reckon$ 9 c&le-p[]4 ,illum9ation4 ,a light giv5 f any s\rce & project$ on a surface1 p] unit ( area1 directly or by reflection4 ,x is /at$ 9 t]ms--z1 = in/ance1 ! c&le-p[] ( a lamp4 ,:5 speak+ ( an inc&esc5t lamp we say x illum9ates equal to f\r c&le-p[] or x gives a light equal to sixte5 c&le-p[]4 ,imm]sion1 ,simple4 ,plat+1 )\t ! aid ( a batt]y1 by simply imm]s+ ! metal 9 a solution ( metallic salt4 ,impulse4 ,! motion produc$ by ! sudd5 or mom5t>y action ( a =ce ^u a body4 ,an electro-magnetic impulse is ! action produc$ by ! electro-magnetic waves 9 magnetiz+ a mass ( s(t iron & attract+ to x ano!r mass ( iron or /eel4 ,an electro-motive impulse is "o :]e ! =ce rises s high z to produce an impulsive dis*>ge su* z t f a ,leyd5-j>4 ,inc&esc5ce1 ,electric4 ,! heat+ ( a conductor to r$ or :ite heat by ! passage ( an electric curr5t4 ,= example1 an inc&esc5t lamp4 ,inc&esc5t ,circuit4 7,see ,circuit1 ,inc&esc5t47 ,inc&esc5t ,lamp-filam5t4 7,see ,filam5t47 ,india-rubb]4 7,see ,ca\t*\c & ,gutta-p]*a47 ,indicator-c>d4 ,! c>d us$ 9 galvanoscopes1 volt & amp]e met]s1 & o!r in/rum5ts4 ,x is provid$ ) a mov+ ne$le & is m>k$ ) a graduat$ scale4 ,induc$4 ,caus$ by induction1 & n directly4 ,induc$ ,curr5t4 7,see ,curr5t1 ,induc$47 ,inductance4 ,t capacity ( a circuit :i* enables x to ex]cise induction & create l9es ( =ce4 ,inductance is ! ratio betwe5 ! total induction ?r\gh a circuit to ! curr5t produc+ x4 ,induction1 ,back4 ,a demagnetiz+ =ce produc$ 9 a dynamo armature :5 a lead is giv5 to ! bru%es4 ,:5 ! bru%es are s set ! w9d+s on ! armature are virtually divid$ into two sets3 "o a direct magnetiz+ set1 ! o!r a cross-magnetiz+ set :i* ex]ts a demagnetiz+ action on ! o!r set4 ,! position ( ! bru%es on a dynamo or motor is indicat$ by _! location1 & if *ang$ back induction w be ! result4 ,induction-coil4 7,see ,coil1 ,induction47 ,induction1 ,electro-magnetic4 ,:5 negative & positive curr5ts are br\ght t[>ds ea* o!r aga9/ _! mat]ial repulsive t5d5cies ! result is "w1 or en]gy1 & ! consequ5t en]gy increases ! int5sity ( bo? curr5ts tempor>ily4 ,! v>iations ?us tempor>ily produc$ 9 ! curr5ts are examples ( electro-magnetic induction4 ,a curr5t is surr\nd$ by l9es ( =ce4 ,! approa* ( two circuits--"o negative1 ! o!r positive--involves a *ange 9 ! l9es ( =ce ab\t ! second>y circuit4 ,l9es ( =ce & curr5t are s intimately connect$ t a *ange 9 "o compels a *ange 9 ! o!r4 ,!re=e1 ! induc$ curr5t 9 ! second>y may be attribut$ to ! *ange 9 ! field ( =ce 9 :i* x lies4 ,! inn] & out] coils ( wire ab\t ! s(t iron wire compos+ an induction-coil are ! be/ & simple/ examples ( electro-magnetic induction4 ,induction1 ,magnetic4 ,! magnetization ( iron or o!r p>amagnetic sub/ances by a magnetic field4 ,! magnetic influ5ce ( a b> excit$ "u ^! conditions is %[n by ?r[+ iron fil+s ^u x4 ,!y w adh]e to bo? ends 7t is at ! negative & positive poles7 b n at ! middle4 ,inductor4 ,a mass ( iron 9 a curr5t g5]ator :i* is mov$ pa/ a magnet-pole to increase ! numb] ( l9es ( =ce issu+ !refrom4 ,x is g5]ally lam9at$1 & is us$ 9 inductor dynamos & motors ( ! alt]nat+-curr5t type4 ,influ5ce1 ,electric4 ,electric induction or influ5ce :i* may be electro-/atic1 curr5t1 or electro-magnetic4 ,influ5ce ,ma*9e4 ,a /atic electric ma*9e work$ by induction1 & us$ to build up *>ges ( opposite nature on two sep>ate prime-conductors4 ,in/allation4 ,! entire app>atus1 build+1 & appurt5ances ( a te*nical or manufactur+ plant or p[]-h\se4 ,an electric-light in/allation w\ld mean ! ma*9]y1 /reet-l9es1 lamps1 etc4 ,insulat+ ,jo9t4 ,us$ = ! purpose ( insulat+ a gas-pipe f an electric circuit4 ,insulat+ ,v>ni%4 ,a v>ni% compos$ ( insulat+ mat]ial1 su* z gums1 %ellac1 or dilut$ rubb]4 ,%ellac dissolv$ 9 alcohol is p]haps ! be/4 ,x is easy to make & dries quickly1 mak+ an insulat+ surface practical = almo/ e ord9>y use4 ,insulation4 ,! dielectric or non-conduct+ mat]ials :i* are us$ to prev5t ! leakage ( electricity4 ,! cov]+ = magnet wires1 & ov]head conduits = p[] l9es & electric light+4 ,insulation1 ,oil4 ,any non-combu/ible oil may be employ$ z an insulator to prev5t electrical leakage 9 induction-coils1 trans=m]s1 & ! l4 ,its pr9cipal advantage lies 9 its be+ 9 liquid =m1 p]mitt+ ( easy h&l+4 ,moreov]1 if pi]c$ by a sp>k f a coil1 x at once closes aga9 )\t becom+ ignit$4 ,a solid insulator1 if pi]c$1 is p]man5tly injur$4 ,insulator4 ,any insulat+ sub/ance or mat]ial to prev5t ! escape ( curr5t4 ,! knobs ( porcela9 or glass to :i* wires are made fa/4 ,insulator1 ,porcela94 ,an insulator made ( porcela9 & us$ to support a wire4 ,int5sity4 ,! int5sity or /r5g? ( a curr5t is its amp]age4 ,! /r5g? ( a magnetic field1 its p[] to attract or magnetize4 ,int]nal ,circuit4 7,see ,circuit1 ,int]nal47 ,int]nal ,resi/ance4 7,see ,resi/ance1 ,int]nal47 ,int]rupt]4 ,a circuit-break]4 ,any device :i* breaks or int]rupts a circuit4 ,x may be op]at$ by h& or automatically4 ,! vibrator ( an induction-coil4 ,! commutators ( an armature4 ,isolat$ ,plant4 ,! sy/em ( supply+ electric en]gy by indep5d5t g5]at+ dynamos = ea* h\se1 factory1 or traction l9e4 ,isolation1 ,electric4 ,a t]m appli$ to 8electric sun/roke40 ,exposure to p[]ful arc-light produces effects resembl+ ^? ( sun/roke4 ,j ,jo9t4 ,! po9t :]e two or m electric conductors jo94 ,jo9t ,resi/ance4 ,! unit$ resi/ance (f]$ by a numb] ( resi/ances connect$ 9 p>allel4 ,jump]4 ,a %ort circuit-%unt employ$ tempor>ily ar\nd an app>atus1 lamp1 or motor to cut out ! curr5t4 ,jump-sp>k4 ,a disruptive sp>k excit$ betwe5 two conduct+ surfaces 9 di/9ction f a sp>k excit$ by a rubb+ contact4 ,k ,kaol94 ,a =m ( e>? or product ( decompos$ feldsp> compos$ ( silica & alum9a4 ,x is s]viceable 9 insulat+ comp\nds4 ,ka?ode4 ,! t]m9al ( an electric circuit :5ce an electrolyz+ curr5t passes f a solution4 ,x is ! t]m9al connect$ to ! z9c pole ( a batt]y or ! article on :i* ! electro-deposit is made4 ,key4 ,! arm ( a telegraphic s\nd] by :i* ! circuit is made & brok54 ,a pivot$ lev] ) a f+]-piece :i*1 :5 depress$1 makes contact betwe5 a po9t & a /ation>y contact on ! base4 ,keybo>d4 ,a bo>d1 or table1 on :i* keys or swit*es are m\nt$4 ,a swit*bo>d4 ,kil[att4 ,a comp\nd unit2 "o ?\s& watts2 an electric-curr5t measure4 ,abbreviation1 ,k-,w4 ,kil[att ,h\r4 ,! result 9 "w equal to ! exp5diture or ex]tion ( "o kil[att 9 "o h\r4 ,k9etoscope4 ,a photographic in/rum5t inv5t$ by ,edison = obta9+ ! effect ( a panorama or mov+ objects by ! display ( pictures 9 rapid succession--9 famili> p>lance1 8mov+ pictures40 ,knife ,swit*4 ,a swit* ) a n>r[ & deep1 movable blade1 or b> ( copp] or brass1 :i* resembles ! blade ( a knife4 ,x is =c$ betwe5 two spr+-clamps atta*$ to "o t]m9al s z to make p]fect contact4 ,l ,lam9at$4 ,made up ( ?9 plates1 z an armature-core4 ,lam9at$ ,core4 7,see ,core1 ,lam9at$47 ,lamp-,arc4 ,a lamp 9 :i* ! light is produc$ by a voltaic arc4 ,c>bon electrodes are us$1 & a special me*anism op]ates & regulates ! space betwe5 ! c>bons s t a p]fect arc may be ma9ta9$4 ,lamp1 ,inc&esc5t4 ,a lamp 9 :i* ! light is produc$ ?r\gh heat+ a filam5t to :it5ess by ! electric curr5t4 ,x consi/s ( a glass bulb f :i* ! air is exhau/$ & seal$1 aft] ! filam5t is enclos$4 ,! ends ( ! filam5t are atta*$ to plat9um wires1 :i* 9 turn are made fa/ to ! contact-plates at ! head ( ! lamp1 s z to connect ) ! curr5t4 ,lamp-socket4 ,a receptacle = an inc&esc5t lamp4 ,x is g5]ally made ( brass & provid$ ) a key-swit* to turn ! curr5t on & (f4 ,lat5t ,electricity4 7,see ,electricity1 ,lat5t47 ,lead4 7,n ! metal47 ,an insulat$ conductor :i* leads to & f a s\rce ( p[]2 an insulat$ conductor to & f a telegraph or telephone in/rum5t2 a circuit1 a batt]y1 or a /ation4 ,n a "p ( ! l9e circuit4 ,t "p ( an electric light or p[] circuit :i* leads f ! ma9 to ! lamps or motors4 ,lead+-9 ,wires4 ,! wires :i* lead into a build+ f an a]ial circuit4 ,! wires :i* lead 9 & out f a lamp1 batt]y1 or in/rum5t4 ,leak4 ,an escape ( electrical en]gy ?r\gh leakage4 ,?is is m liable to occur 9 b>e ?an 9 insulat$ wires4 ,! escape ( curr5t f b>e trolley wires is mu* great] ?an t f ! insulat$ conductors1 p>ticul>ly 9 damp or ra9y wea!r4 ,leclan* ,batt]y4 7,see ,batt]y1 ,leclan*47 ,leyd5-j>4 ,a type ( /atic cond5s]4 ,its usual =m is a glass j>4 ,t9-foil is pa/$ ab\t its inn] & out] surfaces cov]+ ab\t half ! wall4 ,! balance ( ! glass is pa9t$ ) %ellac or insulat+ v>ni%4 ,! m\? is clos$ ) a cork /opp]1 & ?r\gh its c5tre a brass rod is pass$ :i*1 by a %ort *a91 is connect$ ) ! int]ior coat+ ( ! j>4 ,! top ( ! rod is provid$ ) a brass knob or ball1 & f ?is la/ ! sp>k is drawn4 ,lightn+4 ,! electro-/atic dis*>ge ( cl\ds float+ 9 ! atmosph]e4 ,x is ! highe/ =m ( frictional electricity1 uncontrollable & v dang]\s1 s9ce ! /r5g? ( a s+le fla% may run into hundr$s ( ?\s&s ( volts4 ,lightn+-arre/]4 ,an app>atus = use ) electric l9es to c>ry (f to e>? any lightn+ dis*>ges t su* l9es may pick up2 or x may be a =m ( fuse :i* burns out be=e ! curr5t c d any h>m to ! electrical me*anism4 ,l9e-insulator4 ,an insulator s]v+ to support an a]ial l9e4 ,l9eman4 ,a workman ^: bus9ess is ! practical "p ( electrical con/ruction 9 l9es & conduct+ circuits4 ,l9k-fuse4 ,a plate ( fusible metal 9 ! %ape ( a l9k4 ,x is us$ z a safety-fuse 9 connection ) copp] t]m9als4 ,liquefaction1 ,electric4 ,! conv]sion ( a solid into a liquid by ! sole ag5cy ( electricity 9 its heat action ^u ! solid4 ,liquid ,resi/ance4 7,see ,resi/ance1 ,liquid47 ,li?anode4 ,a block ( compress$ lead b9oxide1 ) plat9um connections1 = use 9 a /orage batt]y4 ,li?>ge4 ,yell[-lead4 ,a *emical =m ( metallic lead4 ,load4 ,9 a dynamo1 ! amp]es ( curr5t deliv]$ by x "u giv5 conditions ( spe$1 etc4 ,local ,action4 ,9 a batt]y1 ! loss ( curr5t due to impurities 9 ! z9c4 ,! curr5ts may circulate 9 exce$+ly m9ute circles1 b !y wa/e z9c & *emicals & contribute no?+ to ! effici5cy ( ! batt]y4 ,9 a dynamo1 ! loss ( en]gy ?r\gh ! =mation ( eddy curr5ts 9 its core or armature1 9 ! pole pieces1 or 9 o!r conduct+ bodies4 ,lode/one4 ,! sci5tific "n is magnetite4 ,"s samples possess pol>ity & attract iron2 ^! are call$ lode/ones4 ,loop4 ,a portion ( a circuit introduc$ 9 s]ies into ano!r circuit4 ,l[ ,frequ5cy4 ,a frequ5cy 79 curr5t vibrations7 ( comp>atively few alt]nations p] second4 ,l[ ,pot5tial ,curr5t4 7,see ,curr5t1 ,l[ ,pot5tial47 ,lum9esc5ce4 ,! p[] or prop]ties "s bodies h ( giv+ out light :5 _! molecul> mass is excit$4 ,= example1 phosphorus & radium4 ,lum9\s ,heat4 ,! radiation ( heat by electric curr5t1 :i* at ! same "t produces light4 ,= example1 ! filam5t 9 an inc&esc5t lamp4 ,lum9\s ,j>4 ,a ,leyd5-j> ^: coat+s are ( loz5ge-%ap$ pieces ( t9-foil betwe5 :i* are v %ort spaces4 ,:5 dis*>g$1 sp>ks appe> all ov] ! surface :]e ! small plates ( metal ne>ly jo94 ,m ,magnet4 ,a sub/ance or metal hav+ ! p[] to attract iron & /eel4 ,magnet-b>4 ,a magnet 9 ! %ape ( a /raight b>4 7,see ,b>-magnet47 ,magnet-coil4 ,a coil ( insulat$ wire enclos+ a core ( s(t iron ?r\gh :i* a curr5t ( electricity is pass$ to magnetize ! iron4 ,magnet-core4 ,an iron b> or mass ( iron ar\nd :i* insulat$ wire is w\nd 9 ord] to create an electro-magnet4 ,magnet1 ,electric4 ,a magnet consi/+ ( a b> ( iron1 a bundle ( iron wires1 or an iron tube1 ar\nd :i* a coil ( insulat$ wire is w\nd4 ,:5 a curr5t is pass+ ?r\gh ! coil its influ5ce magnetizes ! iron core1 b directly ! curr5t ceases ! magnetism disappe>s4 ,magnet1 ,field4 ,! electro or p]man5t magnet 9 a dynamo or motor1 us$ to produce ! area ( electric en]gy4 ,magnet1 ,horse%oe4 ,a magnet ( ,u %ape ) ! poles or ends br\ght clos] toge!r ?an ! o!r p>ts ( ! limbs4 ,a s(t iron b> is plac$ across ! poles :5 n 9 use1 z ?is s]ves to cons]ve ! magnetism4 ,magnet1 ,p]man5t4 ,a t]m appli$ to a h>d /eel magnet possess+ high ret5tivity1 or ! p[] to hold its magnetism indef9itely4 ,magnet1 ,regulator4 ,an electro-magnet ^: armature moves 9 su* a mann] z to automatically %ift ! commutator-bru%es1 on a motor or dynamo1 to a position :i* insures ! pres]vation ( bo? bru%es & commutator-b>s1 & also produces a con/ant curr5t4 ,magnet1 ,simple4 ,a magnet made ( "o piece ( metal4 ,magnet ,wire4 ,insulat$ wire us$ = coils4 ,cotton or silk cov]$ wire is ! mo/ s]viceable = w9d+ magnets4 ,magnetic ,adh]5ce4 ,! t5d5cy ( a mass ( iron to adh]e to ! poles ( a magnet4 ,magnetic ,attraction & ,repulsion4 ,! attraction ( a magnet = iron1 /eel1 nickel1 & cobalt2 also ( unlike poles ( magnets = ea* o!r4 ,! l poles repel4 ,magnetic ,circuit-break]s4 ,an automatic swit*1 or break]1 ^: action is excit$ & controll$ by an electro-magnet4 ,magnetic ,conc5tration ( ,ores4 ,! sep>ation ( iron & /eel f _! gangue by magnetic attraction4 ,x is applicable only :5 ei!r ! ore or ! gangue is susceptible to ! magnet4 ,magnetic ,control4 ,! control ( a magnetic ne$le1 magnet1 index1 armature1 or o!r iron indicator 9 a galvanomet]1 ammet]1 or voltmet] by a magnetic field4 ,magnetic ,dip4 ,! incl9ation f ! horizontal position ( a magnetic ne$le t is free to move 9 a v]tical plane4 ,magnetic ,field1 ,rot>y4 ,a magnetic field result+ f a rot>y curr5t4 ,magnetic ,field1 ,%ift+4 ,a magnetic field :i* rotates4 ,its l9es ( magnetic =ce v>y1 !re=e1 9 position4 ,magnetic ,field1 ,uni=m4 ,a field ( uni=m /r5g? 9 all portions1 su* z ! magnetic field ( ! e>?4 ,magnetic ,=ce4 ,! p[] ( attraction & repulsion ex]cis$ by a magnet2 ! =ce ( attraction & repulsion :i* a magnet ex]cises1 & :i*1 9 its ultimate ess5ce1 is unkn[n to sci5ce4 ,magnetic ,induction4 7,see ,induction1 ,magnetic47 ,magnetic ,ne$le4 ,a magnet hav+ a cup or small depression at its c5tre1 & pois$ on a %>p p9 ( brass1 s z to be free to rotate4 ,its ,n pole po9ts to ! nor?1 & its ,s pole to ! s\?4 ,a compass ne$le4 ,magnetic ,poles4 ,! t]re/rial po9ts t[>ds :i* ! nor? or s\? poles ( ! magnetic ne$le are attract$4 ,!re are two poles3 ! arctic1 or negative1 :i* attracts ! positive or ,n pole ( ! magnetic ne$le2 & ! ant>ctic1 or positive1 :i* attracts ! ,s pole ( ! ne$le4 ,magnetic ,poles1 ,false4 ,x has be5 e/abli%$ t !re are o!r poles on ! e>? t attract ! magnetic ne$le :5 ! latt] is br\ght into _! vic9ity4 ,^! are call$ false poles1 & are probably caus$ by l>ge deposits ( iron ly+ close to ! surface ( ! e>?4 ,magnetic ,sep>ator4 ,an app>atus = sep>at+ magnetic sub/ances f mixtures4 ,x is us$ *iefly 9 sep>at+ iron ore f e>? & rock4 ,! m9]al falls on an iron cyl9d]1 or drum1 magnetiz$ by coils1 & adh]es !re1 :ile ! e>? or cru%$ rock drops bel[4 ,! p>ticles ( iron are aft]w>ds remov$ by a scrap]4 ,! ma*9e is also us$ 9 sep>at+ iron fil+s & *ips f brass1 copp]1 or o!r metals1 ! iron adh]+ to ! magnet1 :ile ! brass & o!r *ips drop und]nea?4 ,magnetism4 ,! ph5om5a ( attraction ex]t$ by "o body = ano!r4 ,x has be5 commonly und]/ood t magnetism & electricity are v closely relat$1 = )\t electricity magnetism c\ld n exi/1 al?\gh x has n be5 %[n cle>ly t magnetism plays any "p 9 ! g5]ation ( electricity4 ,magnetism is ! ph5om5al =ce ex]t$ by "o body hav+ two poles 7negative & positive7 = l bodies4 ,! horse%oe magnet or a b> ( magnetiz$ /eel are ! simple/ examples ( ?is4 ,if bo? ends ( ! horse%oe 7 positive !y w\ld n attract1 b w\ld repel4 ,if bo? ends ( a b> 7 positive !y w\ld repel2 b z "o is negative1 or nor?-seek+1 & ! o!r positive1 !y ex]t l9es ( =ce :i* attract l bodies1 su* z bits ( iron1 nails1 & ne$les4 ,no en]gy is requir$ to ma9ta9 magnetism 9 a temp]$ /eel object1 su* z ! wir+ ab\t a s(t iron core :5 x has be5 magnetiz$1 b electric curr5t mu/ fl[ ab\t ! s(t iron core 9 ord] to r5d] x a magnet4 ,s soon z ! curr5t ceases to fl[ ! magnetism ceases & ! s(t iron fails to attract4 ,magnetism1 ,uni=m4 ,magnetism t is uni=m ?r\gh\t a mass ( magnetic /eel1 or a core t is electro-magnetic4 ,magnetize4 ,to imp>t magnetic prop]ty to a sub/ance capable ( receiv+ x4 ,magnetiz+-coil4 7,see ,coil1 ,magnetiz+47 ,magneto ,call-bell4 ,a call-bell us$ pr9cipally 9 telephone sy/ems1 & op]at$ by a curr5t f a magneto-electric g5]ator4 ,! curr5t is excit$ by turn+ ! h&le at ! side ( ! telephone-box be=e remov+ ! receiv] f ! hook4 ,magneto-g5]ator4 ,a curr5t-g5]ator compos$ ( a p]man5t magnet & a revolv+ armature :i* is rotat$ betwe5 ! poles ( ! p]man5t magnet4 ,ma9 ,circuit4 7,see ,circuit1 ,ma947 ,ma9 ,fe$]4 ,! ma9 wire 9 a di/rict to :i* all ! fe$] wires are atta*$4 ,ma9 ,swit*4 ,! swit* connect$ to ! ma9 wire ( a l9e1 or ! ma9-swit* controll+ a numb] ( auxili>y swit*es4 ,ma9s1 ,electric4 ,! l>ge conductors 9 a sy/em ( electric light or p[] di/ribution4 ,make & ,break1 ,automatic4 ,an app>atus :i* enables ! armature ( a magnet to make & break its circuit automatically4 ,make-&-break ,curr5t4 7,see ,curr5t1 ,make-&-break47 ,m]curial ,air-pump4 ,an air-pump op]at$ by m]cury to obta9 a high vacuum1 & us$ ext5sively = exhau/+ inc&esc5t-lamp bulbs4 ,m]cury ,tube4 ,a glass tube seal$ & conta9+ m]cury4 ,x is s arrang$ z to give out fluoresc5t light :5 %ak5 or agitat$ by an electric curr5t4 ,= example1 ! ,geissl] tubes1 ! ,coop]-,hewitt light1 ,crook's tubes1 etc4 ,metallic ,arc4 ,an arc :i* =ms betwe5 metallic electrodes4 ,metallic ,circuit4 7,see ,circuit1 ,metallic47 ,metallic ,conductor4 ,a conductor compos$ ( a metal4 ,metallic ,filam5t4 ,a metal wire us$ 9 an inc&esc5t lamp--! filam5t4 ,metallic ,resi/ance4 7,see ,resi/ance1 ,metallic47 ,metallurgy4 ,! art ( work+ metals4 ,electro-metallurgy applies to ! processes :]e9 electricity plays ! mo/ important "p4 ,mica4 ,a natural m9]al ( %eet =m & transluc5t1 us$ ext5sively z an insulator 9 electrical equipm5t & me*anism4 ,mica1 ,m\ld$4 ,a composition compos$ ( gr\nd mica & %ellac z a b9d]4 ,:5 heat$ & press$ into v>i\s %apes & =ms1 x is a valuable insulator1 & is employ$ = hooks1 locks1 tubes1 sockets1 & ! l4 ,micanite4 ,an insulat+ mat]ial made by cem5t+ lam9ations ( pure mica toge!r & cem5t+ !m ) %ellac or o!r suitable non-conduct+ adhesives4 ,molecul> ,adhesion4 ,! attraction ( simil> molecules = ea* o!r4 ,molecul> ,attraction4 ,! attraction ( molecules1 or physical aff9ity4 ,molecul> ,resi/ance4 ,! resi/ance :i* a mass or electrolyte (f]s :5 conta9$ 9 an insulat$ vessel & a curr5t ( electricity is pass$ ?r\gh x4 ,molecule4 ,"o ( ! invisible p>ticles suppos$ to con/itute matt] ( e k9d2 ! smalle/ p>ticle ( matt] t c exi/ indep5d5tly4 ,x is made up ( atoms1 b an atom _c exi/ alone4 ,morse ,receiv]4 ,! receiv+ in/rum5t once univ]sally us$ 9 ! ,morse sy/em ( telegraphy1 b n[ sup]s$$ by ! s\nd]4 ,morse ,record]4 ,an app>atus :i* automatically records on a ribbon ( pap] ! dots & da%es ( ! ,morse telegraph alphabet4 ,morse ,s\nd]4 ,an electro-magnetic in/rum5t design$ to make a %>p1 click+ s\nd :5 its armature lev] is drawn d[n by ! attraction ( ! magnets4 ,morse ,sy/em4 ,a telegraphic sy/em inv5t$ by ,pr(4 ,s4 ,f4 ,b4 ,morse1 9 :i*1 by means ( alt]nat+ makes & breaks ( v>y+ duration1 ! dots & da%es ( ! ,morse alphabet are reproduc$ & receiv$ at a di/ance ?r\gh ! ag5cy ( wires & ! electro-magnetic s\nd]4 ,motor1 ,electric4 ,a ma*9e or app>atus = conv]t+ electric en]gy into me*anical k9etic en]gy or p[]4 ,! electrical en]gy is usually g5]at$ by a dynamo1 & di/ribut$ on conductors to motors locat$ at v>i\s po9ts4 ,electric motors are ( two types--! ,a-,c41 or alt]nat+ curr5t1 & ! ,d-,c41 or direct curr5t4 ,motor-c>1 ,electric4 ,a self-propell+ c> driv5 by /or$ electricity4 ,motor-dynamo4 ,a motor driv5 by a dynamo ^: armature is firmly atta*$ or connect$ to t ( ! dynamo4 ,x is us$ = modify+ a curr5t4 ,if ! dynamo g5]ates an alt]nat+ curr5t ( high pot5tial1 ! motor conv]ts x into a direct curr5t ( l[] voltage b increas$ amp]age4 ,motor-trans=m]4 ,a trans=m] :i* is op]at$ by a motor4 ,a dynamo-electric ma*9e provid$ ) two armature w9d+s1 "o s]v+ to receive curr5t1 z a motor1 ! o!r to deliv] curr5t1 z a g5]ator1 to a second>y circuit4 ,n ,n4 ,an abbreviation = ! nor?-seek+ pole 9 a magnet4 ,natural ,magnet4 ,a load/one4 ,ne$le4 ,a t]m appli$ to a b>-magnet pois$ horizontally ^u a v]tical po9t4 ,a magnetic ne$le1 or ! magnet 9 a m>9]'s compass4 ,negative4 ,oppos$ to positive4 ,negative ,electricity4 ,! k9d ( electricity ) :i* a piece ( amb] is *>g$ by friction ) flannel4 ,9 a galvanic batt]y or cell ! surface ( ! z9c is *>g$ ) negative electricity4 ,negative electricity1 accord+ to ! !ory ( "s sci5ti/s1 really means a defici5cy ( electricity4 ,negative ,electrode4 ,! same z ,negative ,elem5t4 ,negative ,elem5t4 ,! plate n dissolv$ by ! solution 9 a voltaic cell2 ! "o :i* is positively *>g$4 ,! c>bon1 plat9um1 or copp] plate or pole 9 a batt]y4 ,negative ,fe$]4 ,! conductor :i* connects ! negative ma9s ) ! negative poles ( a g5]ator4 ,negative ,plate4 7,see ,plate1 ,negative47 ,negative ,pole4 7,see ,pole1 ,negative47 ,neutral ,fe$]4 ,! same z ,neutral ,wire4 ,neutral ,wire4 ,! c5tral wire 9 a ?ree-wire sy/em4 ,nickel-ba?4 ,a ba? = ! electro-deposition ( nickel4 ,non-arc+ ,fuse4 ,a fuse-wire :i* is enclos$ 9 a tube pack$ ) asbe/os or silk1 & :i* does n produce an arc :5 x fuses or bl[s out4 ,x is practically noiseless1 save = a slight hiss+ s\nd1 accompani$ by a light puff ( smoke1 :i* escapes f a v5?ole 9 ! side ( ! tube4 ,non-conductor4 ,a mat]ial or sub/ance (f]+ v high resi/ance to ! passage ( ! electric curr5t4 ,non-magnetic ,/eel4 ,alloys ( iron incapable ( be+ magnetiz$4 ,!y are compos$ ( iron & manganese1 nickel1 /eel1 etc4 ,normal4 ,regul>4 ,! av]age value ( obs]v$ quantities4 ,normal curr5t is a regul> curr5t )\t v>iations4 ,! =ce ( a curr5t at :i* a sy/em is int5d$ to "w4 ,normal ,voltage4 ,! same z ,normal ,curr5t4 ,nor? ,pole4 ,! nor?-seek+ pole ( a magnet4 ,! pole ( a magnet :i* t5ds to po9t to ! nor?1 & :5ce l9es ( =ce are assum$ to issue on _! c\rse to ! o!r pole ( ! magnet4 ,o ,o4 ,an abbreviation = ,ohm4 ,o]/$'s ,discov]y4 ,o]/$ discov]$1 9 #ahbj1 t a magnetic ne$le t5d$ to place itself at "r angles to a curr5t ( electricity4 ,?is fundam5tal pr9ciple is ! basis ( ! galvanomet]1 ! dynamo1 & ! motor4 ,ohm4 ,! practical unit ( resi/ance4 ,a legal ohm is ! resi/ance ( a column ( m]cury "o squ>e millimetre 9 cross-sectional area & #ajf4bd c5timetres 9 l5g?4 ,ohm1 ,true4 ,! true ohm is ! resi/ance ( a column ( m]cury #ajf4bd c5timetres long & "o squ>e millimetre 9 cross-sectional area4 ,an ohm may be measur$ by a ,no4 #cj copp] wire n9e feet & n9e in*es long4 ,if l>g] size wire is us$ ! piece mu/ be proportionately long]1 s9ce ! resi/ance is less4 ,ohmic ,resi/ance4 ,true resi/ance z di/+ui%$ f spuri\s resi/ance1 or c\nt] electro-motive =ce4 7,see also ,resi/ance1 ,ohmic47 ,ohm's ,law4 ,! basic law :i* expresses ! relations betwe5 curr5t1 electro-motive =ce1 & resi/ance 9 active circuits4 ,x is =mulat$ z foll[s3 #a4 ,! curr5t /r5g? is equal to ! electro-motive =ce divid$ by ! 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 ,o4 ,k4 ,a telegraphic signal mean+ yes1 or all "r4 ,x is suppos$ to be a misspell$ =m ( all correct1 8,oll ,k]rekt40 ,okonite4 ,a =m ( insulation = wires & conductors2 a trade "n appli$ to insulations1 & protect$ by copyright4 ,op5 ,arc4 ,a voltaic arc n enclos$4 ,op5 ,circuit4 7,see ,circuit1 ,op547 ,oscillat+ ,curr5t4 7,see ,curr5t1 ,oscillat+47 ,outlet4 ,t "p ( an electroli] or electric light fixture out ( :i* ! wires are l$ = atta*m5t to inc&esc5t light sockets4 ,outside ,wir+4 ,! wir+ = an electric circuit :i* is locat$ outside a build+ or o!r /ructure4 ,ov]head ,fe$]s4 ,! same z ov]head conductors4 ,ov]head ,trolley4 ,! sy/em 9 :i* ! curr5t = ! propulsion ( trolley-c>s is tak5 f ov]head fe$]s or wires4 ,ov]head ,trolley-wire4 ,a nak$1 h>d copp] wire drawn at high t5sion1 & susp5d$ ov] or at ! side ( a c>-track1 & f :i* ! trolley-:eel takes its curr5t4 ,ov]load4 ,9 an electric motor1 an excess ( me*anical load prev5ts economical work+1 caus+ ! armature to revolve sl[ly & ! wir+ to heat4 ,9 ?is case heat+ implies wa/e ( en]gy4 ,ov]load ,swit*4 ,a swit* :i* op]ates automatically to op5 a circuit 9 l9e ) a motor1 & s save ! motor f ov]heat+ or burn+ 9 ! ev5t ( an ov]load4 ,p ,pap] ,cable4 ,a cable insulat$ ) wax$ or p>aff9$ pap]4 ,p>aff9e4 ,a residuum ( petroleum oil1 valuable z an insulat+ m$ium 9 electrical "w4 ,a hydro-c>bon composition ( ! highe/ resi/ance kn[n4 ,x is ext5sively us$ 9 cond5s]s & o!r electrical app>atus z a dielectric & insulator4 ,p>allel ,di/ribution4 ,a di/ribut+ sy/em = electricity :]e9 ! receptive contrivances are adju/$ betwe5 e two ( a numb] ( p>allel conductors runn+ to ! limits ( ! sy/em4 ,:5 two or m conductors connect two ma9s ( comp>atively l>ge size & l[ resi/ance1 !y are said to be 9 p>allel or 9 multiple4 ,?is ord] is easily pictur$ by imag9+ ! ma9s to be ! sides ( a ladd] & ! conductors ! rungs4 ,9 ! latt] ! lamps are plac$4 ,x foll[s t ! curr5t fl[s f "o ma9 to ! o!r ?r\gh ! conductors & lamps4 ,p>amagnetic4 ,sub/ances :i* h magnetic prop]ties1 or ^? :i* are attract$ by magnetic bodies4 ,a p>amagnetic sub/ance has high multiply+ p[] = l9es ( =ce1 !re=e a b> ( iron :i* is a p>amagnetic sub/ance ( ! highe/ quality becomes magnetic :5 plac$ )9 a circle ( electric l9es ( =ce4 ,! fir/ example ( p>amagnetic sub/ance br\ght to ! att5tion ( man 0 ! lode/one1 f :i* ! anci5t m>9]s fa%ion$ _! crude compass ne$les4 ,p-,c4 ,an abbreviation = por\s cup4 ,pe> ,pu%4 ,a pu%-button enclos$ 9 a h&le hav+ ! %ape ( a pe>4 ,x is g5]ally atta*$ to ! end ( a flexible wire cord4 ,p]iodic ,curr5t4 7,see ,curr5t1 ,p]iodic47 ,p]man5cy1 ,electric4 ,! p[] ( conductors to reta9 _! conductivity unaffect$ by ! lapse ( "t4 ,p]man5t ,magnet4 7,see ,magnet1 ,p]man5t47 ,phase4 ,"o complete oscillation4 ,! int]val elaps+ f ! "t a p>ticle moves ?r\gh ! middle po9t ( its c\rse to ! in/ant :5 ! phase is to be /at$4 ,simple h>monic motion4 ,oscillation4 ',phone4 ,an abbreviation = ! ^w ,telephone4 ,phonograph4 ,an app>atus = reproduc+ s\nd4 ,x is vibratory & n electric 9 its action1 except t ! me*anism may be driv5 by electricity4 ,x consi/s ( a rotat+ cyl9d] ( a waxlike mat]ial & a glass diaphragm c>ry+ a ne$le-po9t t lightly t\*es ! surface ( ! wax5 cyl9d]4 ,if ! diaphragm is agitat$ ! ne$le vibrates1 mak+ ind5tations 9 ! surface ( ! wax4 ,if ! ne$le is set back & ! cyl9d] rotat$ s z to c>ry ! po9t ov] ! ind5tations1 ! s\nd is giv5 back ?r\gh ! vibration ( ! diaphragm4 ,pickle4 ,an acid solution us$ to cleanse metallic surfaces prep>atory to electro-plat+4 ,pilot ,wires4 ,wires br\ght f di/ant p>ts ( electric light & p[] ma9s1 & lead+ to voltmet]s at a c5tral /ation4 ,?r\gh _! ag5cy ! pot5tial en]gy ( e "p ( ! sy/em may be measur$4 ,pi?-balls4 ,balls made f ! pi? ( light wood1 su* z eld]4 ,!y are us$ 9 ! con/ruction ( electroscopes & = o!r exp]im5ts 9 /atic electricity4 ,plant4 ,! app>atus = g5]at+ electric curr5t1 includ+ eng9es1 boil]s1 dynamos1 ma9s1 & subsidi>y app>atus4 ,plate1 ,cond5s]4 ,9 a /atic app>atus1 ! cond5s] hav+ a flat piece ( glass = a dielectric4 ,x is m\nt$ on an axle s t x may be revolv$4 ,plate1 ,gr\nd4 ,9 a lightn+-arre/]1 ! plate connect$ to ! e>? or gr\nd wire4 ,plate1 ,negative4 ,9 a voltaic batt]y1 ! plate :i* is unattack$ by ! fluid4 ,x is made ( c>bon1 plat9um1 or copp]4 ,plate1 ,positive4 7,see ,positive ,plate47 ,plat+-ba?4 ,a vessel ( solution = ! deposition ( metal by electrolysis4 ,us$ 9 electro-plat+4 ,plat+1 ,electro4 ,! process ( deposit+ metal on surfaces ( metals or o!r sub/ances by ! aid ( an electrolyte & ! electric curr5t4 ,plat9um ,fuse4 ,a sl5d] wire ( plat9um r\s$ to inc&esc5ce by curr5t1 & us$ to explode a *>ge ( p[d] or o!r combu/ible sub/ance4 ,plug4 ,a piece ( metal1 ) a h&le1 us$ to make electric connections by be+ ins]t$ betwe5 two slightly sep>at$ plates or blocks ( metal4 ,a w$ge ( metal1 slightly tap]$1 & us$ to ?ru/ betwe5 two conductors to close or complete a circuit4 ,plumbago4 ,s(t1 lu/r\s graphite2 a native =m ( c>bon sometimes *emically purifi$4 ,x is us$ *iefly 9 electrotyp+ = du/+ ! wax m\lds to make ! surface an electric conductor4 ,plunge-batt]y4 7,see ,batt]y1 ,plunge47 ,pol>4 ,p]ta9+ to "o ( ! poles ( a magnet4 ,pol>ity4 ,! disposition 9 a body to place its axis 9 a p>ticul> direction :5 influ5c$ by magnetism4 ,= example1 ! attraction & repulsion at ! opposite ends ( a magnet4 ,! ,n & ,s seek+ poles ( a compass ne$le is ! simple/ example4 ,pol>ity1 ,electric4 ,! disposition 9 a p>amagnetic body to be influ5c$ by electric waves & l9es ( =ce4 ,! o!rwise non-magnetic body or mass becomes magnetic to attract or repulse :5 influ5c$ by electricity1 b ceases to reta9 ! ph5om5a aft] ! electric influ5ce is remov$4 ,a piece ( s(t iron wire1 a nail1 or a %ort rod ( iron w become electro-pol>iz$ :5 a curr5t ( electricity is s5t ?r\gh a coil ( insulat$ wire s w\nd t "o end w be ,n ! o!r ,s4 ,s soon z ! circuit is brok5 ! pol>ity ceases4 ,pol>ization4 ,! depriv+ ( a voltaic cell ( its prop] electro-motive =ce4 ,?is may be br\ght ab\t ?r\gh ! solution becom+ sp5t1 or 9 ! ev5t ( ! acid be+ saturat$ ) z9c1 & s fail+ to act on ! metallic z9c4 ,c\nt] electro-motive =ce due to ! accumulation ( hydrog5 on ! negative plate4 ,pol>iz+-curr5t4 7,see ,curr5t1 ,pol>iz+47 ,pol> ,surface4 ,! surface ( a magnetic sub/ance ?r\gh :i* ! magnetic flux passes 9 or out4 ,pole-*ang]4 ,an automatic1 oscillat+ swit* or contact-break] :i* rev]ses ! direction ( ! curr5t4 ,pole1 ,negative4 ,! ,s pole 9 a magnet or compass ne$le4 ,pole1 ,positive4 7,see ,positive ,pole47 ,pole-swit*1 ,s+le4 ,a swit* design$ to op5 or close "o lead only4 ,poles4 ,! t]m9als ( an op5 electric circuit at :i* !re necess>ily exi/s a pot5tial diff]5ce4 ,! t]m9als ( an op5 magnetic circuit1 or ! ends ( a magnetiz$ mass ( iron4 ,porcela94 ,a f9e v>iety ( e>!nw>e1 valuable = insulators & insulat+ purposes4 ,porosity4 ,! /ate or prop]ty ( hav+ small int]/ices or holes4 ,! opposite ( d5sity4 ,por\s ,cup or ,cell4 ,a cup or cell made ( pipe-clay or ( unglaz$ e>!nw>e ?r\gh :i* a curr5t ( electricity c pass :5 wet or 9 a liquid4 ,por\s cups are us$ 9 cells & batt]ies to keep two liquids ap>t1 & yet p]mit electrolysis & electrolytic conduction4 ,positive ,curr5ts4 ,curr5ts :i* deflect ! ne$le to ! left4 ,positive ,electricity4 ,! curr5t t fl[s f ! active elem5t1 ! z9c 9 a batt]y1 to ! c>bon4 ,! negative electricity fl[s f ! c>bon to ! z9c4 ,positive ,electrode4 ,! electrode :i* is connect$ ) ! positive pole ( a s\rce ( electric en]gy4 ,positive ,fe$]s4 ,! lead or wire 9 a set ( fe$]s :i* is connect$ to ! positive t]m9al ( ! g5]ator4 ,positive ,plate4 ,9 a voltaic cell1 ! plate :i* is act$ ^u & corrod$4 ,! curr5t f ! positive plate is negative electricity4 ,positive ,pole4 ,! ,n pole 9 a magnet or magnetic ne$le4 ,s call$ because x seeks ! nor? or negative pole ( ! e>?4 ,positive ,wire1 or ,conductor4 ,! wire1 or conductor1 connect$ ) ! positive pole ( any app>atus :i* produces electro-motive =ce4 ,pot5tial1 ,electric4 ,! p[] to p]=m electric "w4 ,pot5tial ,en]gy4 ,capacity = do+ "w4 ,pot5tial en]gy :5 lib]at$ becomes actual en]gy = ! p]=mance ( "w4 ,p[]-g5]ator4 ,any s\rce f :i* p[] is g5]at$4 ,p[]-h\se4 ,a /ation 9 :i* ! plant ( an electric p[] sy/em is op]at$ & ! curr5t di/ribut$ to local or long-di/ance po9ts4 ,p[]-h\ses are ei!r prim>y or second>y /ations4 ,9 ! prim>y /ation ! curr5t is g5]at$ directly by ! aid ( me*anical p[]1 ei!r ! /eam-eng9e or ! /eam-turb9e4 ,! second>y /ation1 or sub-/ation1 is locat$ at a di/ance f ! ma9 p[]-h\se1 & has no me*anical means ( g5]at+ curr5t4 ,! curr5t1 usually ( high alt]nat+ voltage1 is suppli$ to ! sub-/ation f ! ma9 p[]-h\se2 & by means ( trans=m]s & conv]t]s1 ! high-voltage curr5t is trans=m$ into "o ( l[] ,e-,m-,f & high] amp]age1 = di/ribution ov] local l9es4 ,p[]-unit4 ,! unit ( electric p[] is ! volt-amp]e or watt4 ,pressure1 ,electric4 ,electro-motive =ce or voltage4 ,prim>y4 ,a t]m us$ to designate ! induction-coil 9 an induction-app>atus or trans=m]4 ,x is an abbreviation = prim>y coil4 ,prim>y ,batt]y4 7,see ,batt]y1 ,prim>y47 ,prime ,conductor4 7,see ,conductor1 ,prime47 ,pu%-button4 ,a swit* = clos+ a circuit by means ( pressure appli$ to a button4 ,! button is provid$ ) a spr+1 s t :5 pu%$ 9 & releas$ x flies back1 reop5+ ! circuit4 ,pyrogravure4 ,a process ( engrav+ by ! use ( plat9um po9ts heat$ to r$ness by ! electric curr5t4 ,q ,q4 ,abbreviation or symbol = electric quantity4 ,quadrant4 ,! qu>t] ( a circle or ( its circumf]5ce4 ,quadruple ,circuit4 7,see ,circuit1 ,quadruple47 ,quantity4 ,! t]m is appli$ to express arrangem5ts ( electrical connections = giv+ ! l>ge/ possible am\nt ( curr5t4 ,quantity1 ,electro-magnetic4 ,! electro-magnetic curr5t measur$ by its int5sity = a second ( "t4 ,quick-break4 ,a break affect$ 9 an electric curr5t by ! employm5t ( a quick-break swit*4 ,quick5+4 ,! amalgamat+ ( ! surface ( a metallic object be=e electro-plat+ x ) silv]4 ,?is secures bett] adhesion ( ! deposit1 & is done by dipp+ ! article into a solution ( m]curial salts--"o "p ( m]curic nitrate to "o hundr$ p>ts ( wat]4 ,r ,radiant ,en]gy4 ,en]gy exi/+ 9 ! lum9if]\s e!r & ex]cis$ 9 wave transmission1 creat+ light or s\nd4 ,radium possesses ! highe/ =m ( radiant en]gy4 ,radiate4 ,to emit or s5d out 9 direct l9es f a po9t or po9ts1 z radiat+ heat1 light1 or s\nd4 ,! radiations are s5t out 9 all directions f a c5tral po9t1 j z a /one ?r[n 9 a pond ( /ill wat] w radiate waves or ripples f ! c5tral po9t4 ,radiation4 ,! travell+ or motion ( e!r waves ?r\gh space4 ,radiator1 ,electric4 ,a s]ies ( plates or wire-coils heat$ by curr5t4 ,!y radiate heat & s w>m ! surr\nd+ air4 ,radiograph4 ,a photographic picture tak5 by ! ,x-ray process4 ,receiv]4 ,9 telephony or telegraphy1 an in/rum5t = receiv+ ! message z di/+ui%$ f ! in/rum5t s5d+ or transmitt+ ! message4 ,! telephone piece held to ! e> is ! receiv]4 ,receiv+ ,end4 ,! end ( a l9e :]e ! op]ative curr5ts are receiv$1 z oppos$ to ! end at :i* !y are transmitt$4 ,receptacle4 ,a device = ! in/allation ( an atta*m5t or ext5sion plug4 ,us$ 9 connection ) electric-light+ circuits4 ,recoil ,kick4 ,reaction result+ f a disruptive dis*>ge4 ,record]4 ,9 telegraphy1 ! receiv+ app>atus = record+ ! dot-&-da% signals on a /rip or tape ( pap]4 ,r$uction4 ,! influ5ce ex]t$ )\t app>5t communication by a magnetic field or a *>g$ mass ^u neighbor+ bodies4 ,! induction-coil is a simple example ( ?is =ce4 ,! curr5t passes ?r\gh ! prim>y or inn] coil ab\t a core ( s(t iron1 & 9 do+ s x develops l9es ( =ce 9 ! second>y or out] coils1 al?\gh no curr5t is fl[+ directly ?r\gh !m f a batt]y or dynamo4 ,r$uction ,ge>4 ,a ge> :i* acts to r$uce a spe$ bel[ t ( a motor 9 full motion )\t less5+ its motive =ce4 ,refract4 ,to break ! natural c\rse ( light 9 an ela/ic m$ium4 ,! rays ( light1 z !y pass f a r>e into a d5se m$ium1 are refract$4 ,regi/]1 ,electric4 ,an app>atus = regi/]+ & record+ ! movem5ts ( employs ab\t a build+4 ,press-buttons are arrang$ ?r\gh\t ! build+1 & :5 a man passes a /ation he presses ! button1 & ! "t is record$ by ! app>atus4 ,regulator ,magnet4 7,see ,magnet1 ,regulator47 ,relay4 ,a telegraphic or telephonic receiv+ in/rum5t :i* op5s & closes a local circuit ?r\gh movem5ts caus$ by ! impulses ( curr5ts receiv$4 ,! relay batt]y may be v delicate s z to "w ) weak curr5ts4 ,! function ( ! relay is to op5 & close circuits = ! admission ( a new curr5t to pu% on ! s\nd or vibration to a m di/ant po9t4 ,! ma9 batt]y may be ( any desir$ p[]4 ,relay ,connection4 ,a connection us$ 9 telegraphy1 includ+ a local batt]y1 ) a %ort circuit1 normally op51 b clos$ at w by a swit* & s\nd]1 or o!r appliance4 ,a v weak curr5t w "w ! app>atus4 ,relay1 ,ord9>y4 ,a relay t is n pol>iz$4 ,relay1 ,repeat+4 ,9 telegraphy1 a relay = repeat+ ! signals ?r\gh a second l9e4 ,reluctance4 ,magnetic resi/ance4 ,repeat]4 ,9 telegraphy1 an in/rum5t = repeat+ ! signals ?r\gh a second l9e4 ,x is virtually a relay :i* is controll$ by ! s5d]1 & :i*1 9 turn1 op]ates ! re/ ( ! ma9 l9e4 ,x is usually locat$ at ab\t ! middle ( ! total di/ance cov]$4 ,repeat+-/ation4 ,a telegraph /ation locat$ on a long l9e1 & occupy+ a position at ! juncture ( ! sections into :i* ! l9e is divid$4 ,! curr5ts receiv$ ?r\gh "o section are repeat$ into ! o!r sections by means ( a repeat]4 ,repulsion1 ,electric4 ,! t5d5cy :i* exi/s betwe5 two bodies *>g$ alike to mutually repel ea* o!r4 ,residual ,*>ge4 7,see ,*>ge1 ,residual47 ,resili5ce4 ,! p[] to spr+ back to a =m] position4 ,electricity is resili5t1 al?\gh its ela/icity _c be measur$ accurately4 ,res94 ,a solid inflammable sub/ance or gum1 & a good non-conductor 9 electrical "w4 ,x is ! product obta9$ by di/ill+ ! sap ( ! pit*-p9e4 ,! "n is also appli$ to ! product ( di/ill+ ! sap ( o!r trees4 ,common res91 %ellac1 lac1 ,dragon's-blood1 & o!r sub/ances ( a simil> nature are res9s4 ,!y are all dielectrics1 & ! s\rce ( negative frictional electricity :5 rubb$ ) cotton1 wool1 flannel1 silk1 or fur4 ,resi/ance4 ,t quality ( an electric conductor 9 virtue ( :i* x opposes ! passage ( an electric curr5t1 caus+ ! disappe>ance or modification ( electro-motive =ce1 & conv]t+ electric en]gy into heat en]gy4 ,resi/ance-box4 ,a box fill$ ) resi/ance-coils connect$ 9 s]ies & provid$ ) a swit*1 s t any numb] ( ! coils may be cut out4 ,resi/ance1 ,c>bon4 ,a resi/ance compos$ ( c>bon z a sub/itute = a coil ( wire4 ,c>bon rods are plac$ close toge!r hav+ an air space betwe5 !m1 ) alt]nate ends connect$4 ,piles may be built up ( c>bon plates1 ^: resi/ance is made to v>y by *ang+ ! pressure4 ,resi/ance-coil4 ,a coil ( wire metal or o!r sub/ances hav+ ! p[] to resi/ a curr5t ( electricity4 ,a coil ( wire us$ to measure an unkn[n resi/ance by virtue ( its own kn[n resi/ance4 7,see also ,coil1 ,resi/ance47 ,resi/ance1 ,dielectric4 7,see ,dielectric ,resi/ance47 ,resi/ance1 ,electrolytic4 ,! resi/ance ( an electrolyte to ! passage ( a curr5t decompos+ x4 ,x is almo/ entirely due to electrolysis1 & is int5sifi$ by c\nt]-electro-motive =ce4 ,:5 a curr5t ( a voltage s l[ z n to decompose an electrolyte is pass$ ?r\gh ! latt]1 ! resi/ance appe>s v high & sometimes almo/ inf9ite4 ,if ! voltage is increas$ until ! electrolyte is decompos$ ! resi/ance sudd5ly drops to a po9t l[] ?an ! true resi/ance4 ,resi/ance1 ,int]nal4 ,! resi/ance ( a batt]y1 or g5]ator1 9 an electric circuit z di/+ui%$ f ! resi/ance ( ! re/ ( ! circuit4 ,resi/ance1 ,liquid4 ,a liquid ( v>y+ specific gravity us$ to create resi/ance to ! passage ( ! electric curr5t4 ,resi/ance effect$ by ! use ( liquid ?r\gh :i* a curr5t mu/ pass to complete a circuit4 ,resi/ance1 ,metallic4 ,! resi/ance ( metals to ! electric curr5t4 ,g]man-silv] resi/ance z di/+ui%$ f t ( wat]1 c>bon1 or o!r sub/ances4 ,resi/ance1 ,ohmic4 ,true resi/ance measur$ 9 ohms z di/+ui%$ f c\nt] electro-motive =ce4 7,see also ,ohmic ,resi/ance47 ,resi/ance1 ,spuri\s4 ,! c\nt]-electro-motive =ce4 ,9 its effect ( oppos+ a curr5t & 9 resi/+ its =mation x diff]s f true resi/ance4 ,true resi/ance dim9i%es curr5t /r5g?1 absorbs en]gy1 & develops heat4 ,spuri\s resi/ance opposes & dim9i%es a curr5t )\t absorption ( en]gy or production ( heat4 ,resi/ance1 ,/&>d4 ,a kn[n resi/ance employ$ to det]m9e unkn[n resi/ances by comp>ison4 ,resi/ance1 ,true4 ,! true resi/ance measur$ 9 ohms z di/+ui%$ f c\nt]-electro-motive =ce4 ,resonator1 ,electric4 ,a small1 op5 electric circuit ) ends ne>ly t\*+4 ,:5 expos$ to electric resonance1 or to a sympa!tic electric oscillat+ dis*>ge1 a sp>k passes across ! gap4 ,! sp>k is due to inductance 9 ! resonator4 ,ret5tiv5ess4 ,t prop]ty :i* enables /eel to reta9 its magnetism4 ,return4 ,a l9e or conductor :i* c>ries curr5t back to its />t+-po9t aft] x has trav]s$ a circuit4 ,! be/ def9ition ( a return is a circuit on :i* no new app>atus is in/all$4 ,return-circuit4 7,see ,circuit1 ,return47 ,return-circuit1 ,railway4 ,a gr\nd$ circuit us$ 9 trolley sy/ems = gr\nd returns ?r\gh ! tracks1 !y be+ jo9$ by l9ks or flexible wires s z to =m p]fect conductors4 ,x is ! negative side ( ! sy/em1 ! positive be+ 9 ! ov]head or und]gr\nd fe$-wire or rail4 ,rev]sibility4 ,! pr9ciple by :i* any =m ( g5]ator = produc+ a giv5 =m ( en]gy may be rev]s$ to absorb en]gy4 ,! dynamo ( ! rev]sible type driv5 to g5]ate curr5t may be rev]s$ & w develop p[] if a curr5t is run ?r\gh x4 ,rheo/at4 ,an adju/able resi/ance4 ,an app>atus = *ang+ ! resi/ance1 )\t op5+ ! circuit1 by ?r[+ a swit*-b> across contact po9ts4 ,rod ,clamp4 ,a clamp us$ 9 ! lamp rod ( an arc-light to hold ! c>bon4 ,rntg5 ,effects4 ,ph5om5a obta9$ by ! use ( ! ,x or ,rntg5 rays4 ,rntg5-ray ,scre54 ,a scre5 ^: surface is cov]$ ) fluoresc5t mat]ial = ! purpose ( receiv+ & display+ ! ,rntg5 image4 ,rntg5 ,rays4 ,a peculi> =m ( light radiation discov]$ by ,rntg51 & :i* is emitt$ f t portion ( a high vacuum tube ^u :i* ! ka?ode rays fall4 ,rot>y ,magnetic ,field4 7,see ,magnetic ,field1 ,rot>y47 ,ruhmkorff ,coil4 7,see ,coil1 ,ruhmkorff47 ,s ,safety ,fuse4 ,a device to prev5t ov]heat+ ( any portion ( a circuit by excessive curr5t4 ,x g5]ally consi/s ( a /rip ( fusible metal :i*1 if ! curr5t atta9s too great /r5g?1 melts & op5s ! circuit4 ,salt4 ,a *emical comp\nd conta9+ two atoms or radicals :i* saturate ea* o!r4 ,"o is electro-positive1 ! o!r electro-negative4 ,salts are decompos$ by electrolysis1 & 9 sep>at+ !y comb9e to =m new molecules4 ,saturat$4 ,a liquid is said to be saturat$ :5 x has dissolv$ all ! salts x w take up4 ,se>*-light4 ,an app>atus = produc+ a p[]ful beam ( light & project+ x 9 any desir$ direction4 ,second>y4 ,a t]m appli$ to ! second>y coil ( a trans=m] or induction-coil4 ,second>y ,batt]y4 7,see ,batt]y1 ,second>y47 ,second>y ,plates4 ,! plates ( a second>y batt]y or /orage-batt]y4 ,:5 *>g$1 ! negative plate %\ld be br[n or deep r$di% 9 color1 & ! positive slate-color$4 ,self-excit$4 ,electrifi$ by its own curr5t4 ,self-w9d+ ,clock4 ,a clock :i* automatically w9ds itself by electricity4 ,x is op]at$ by a small electro-magnetic motor :i* obta9s its curr5t f an outside s\rce4 ,semaphore1 ,electric4 ,an app>atus = exhibit+ signals4 ,us$ 9 ! railway block sy/em4 ,s]ies4 ,arrang$ 9 succession4 ,:5 inc&esc5t lamps are in/all$ s t ! curr5t goes 9 & out ( "o lamp1 & s on to ! next & ! succe$+ ones1 !y are said to be arrang$ 9 s]ies4 ,x takes high ,e-,m-,f & curr5t1 or amp]age1 to op]ate su* lamps4 ,s]ies batt]ies are arrang$ ) ! z9c pole ( "o connect$ to ! c>bon pole ( ! next4 ,s]ies ,arc ,cut-out4 ,a device by means ( :i* a %ort circuit is e/abli%$ pa/ a defective lamp1 !reby secur+ ! undi/urb$ op]ation ( all ! o!r lamps 9 ! circuit4 ,s]ies ,di/ribution4 ,a di/ribution ( electricity 9 :i* ! receptive devices are arrang$ 9 successive ord] ^u "o conductor1 ext5d+ ! entire l5g? ( ! circuit4 ,s]ies ,dynamo4 ,a s]ies-w\nd dynamo4 ,s]ies ,inc&esc5t ,lamp4 ,an inc&esc5t lamp adapt$ = s]vice 9 a s]ies circuit4 ,s]ies ,motor4 ,a motor adapt$ = use 9 a s]ies circuit2 a motor ^: field-coil w9d+ is 9 s]ies ) ! armature4 ,s]ies1 ,multiple4 ,an arrangem5t ( electric app>atus 9 :i* ! p>ts are gr\p$ 9 sets 9 p>allel1 & ^! sets are connect$ 9 s]ies4 ,s]ies ,w9d+4 ,a me?od ( w9d+ a g5]ator or motor 9 :i* "o ( ! commutator bru% connections is jo9$ to ! field-magnet w9d+4 ,! o!r end ( ! magnet w9d+ is connect$ ) ! out] circuit1 & ! second armature bru% is c\pl$ ) ! rema9+ t]m9al ( ! out] circuit4 ,s]vice ,wires4 ,wires connect$ to ! supply circuit or ma9 wires1 & :i* run into build+s to supply curr5t = heat1 light1 & p[]4 ,%ellac4 ,a res9 gum1 ga!r$ f c]ta9 ,asiatic trees4 ,x is soluble 9 alcohol1 & is us$ ext5sively 9 electric "w z an insulator4 ,%ift+ ,magnetic ,field4 7,see ,magnetic ,field1 ,%ift+47 ,%ock1 ,electric4 ,! effect ^u ! animal sy/em ( ! dis*>ge ( an electric curr5t ( high pot5tial diff]5ce4 ,! voltage is ! ma9 elem5t 9 a %ock4 ,%oe4 ,z appli$ to electric railways1 ! ca/+ employ$ to be> on ! ?ird rail to take 9 positive curr5t & electro-motive =ce4 ,! ca/-iron plate ( an electric break1 :i*1 by magnetism1 adh]es to ano!r iron surface4 ,%ort ,circuit4 7,see ,circuit1 ,%ort47 ,%unt-box4 ,a resi/ance-box design$ = use z a galvanomet] %unt4 ,! box conta9s a s]ies ( resi/ance-coils :i* c be plugg$ 9 or out z requir$4 ,%unt-w9d+4 ,a dynamo or motor is %unt-w\nd :5 ! field-magnet w9d+ is p>allel ) ! w9d+ ( ! armature4 ,silv]-ba?4 ,a solution ( a salt ( silv] us$ 9 ! electro-plat+ process4 ,silv]-plat+4 ,deposit+ a coat+ ( silv] on a metallic surface by ! acid ( electro-metallurgy4 ,silv]-/ripp+ ,ba?4 ,an acid solution us$ = /ripp+ silv] f a metallic surface be=e re-plat+ x4 ,simple ,circuit4 7,see ,circuit1 ,simple47 ,simple ,imm]sion4 7,see ,imm]sion1 ,simple47 ,simple ,magnet4 7,see ,magnet1 ,simple47 ,s+le-trolley ,sy/em4 ,a trolley sy/em employ+ only "o ov]head conduct+ wire1 ! track & gr\nd s]v+ z ! return-circuit4 ,s+le-w\nd ,wire4 ,wire insulat$ by w9d+ or ov]lay+ ) b a s+le lay] ( mat]ial4 ,slid+-cond5s]4 7,see ,cond5s]1 ,slid+47 ,snap-swit*4 ,a swit* s contriv$ z to give a quick break4 ,a spiral spr+ is fa/5$ betwe5 ! h&le & arm 9 su* a mann] t :5 ! h&le is drawn back ! spr+ op]ates & quickly draws a knife-b> f ! keep]1 break+ ! contact in/antly & )\t ! =mation ( an arc4 ,socket4 ,a receptacle = an inc&esc5t lamp or plug4 ,sol5oid4 ,a helical coil ( wire ( uni=m diamet] or cyl9drical 9 %ape4 ,x is useful 9 exp]im5ts ) electro-magnetism4 ,solution4 ,a fluid compos$ ( dissolv$ salts2 a mixture ( liquids & fluids4 ,s\nd ,waves4 ,waves produc$ 9 an ela/ic m$ium by sonor\s vibration1 z 9 wireless telegraphy4 ,s\nd]4 ,9 telegraphy1 ! in/rum5t op]at$ on by ! key at ! o!r end ( a l9e4 ,v>i\s devices are employ$ to increase _! resonance--z1 = in/ance1 holl[ boxes4 ,s\nd]s are g5]ally plac$ on local circuits & are actuat$ by relays4 ,s\nd]1 ,repeat+4 ,a telegraphic in/rum5t :i* repeats a message into ano!r circuit4 ,s-,p4 ,an abbreviation = s+le pole4 ,sp>k-arre/]4 ,a scre5 ( wire-nett+ fitt$ ar\nd ! c>bons ( arc-lamps to prev5t ! *ips or hot sp>ks f fly+4 ,sp>k-coil4 ,a coil = produc+ a sp>k f a s\rce ( comp>atively l[ electro-motive =ce4 ,! induction-coil is an example4 ,sp>k1 ,electric4 ,! ph5om5on obs]v$ :5 a disruptive *>ge leaves an accumulator or induction-coil & passes ?r\gh an air gap4 ,sp>k-gap4 ,! space left betwe5 ! ends ( an electric resonator across :i* ! sp>k spr+s4 ,sp>k+4 ,! production ( sp>ks at ! commutator1 betwe5 ! b>s & ! bru%es ( dynamos & motors4 ,!y are m9ute voltaic arcs1 & %\ld n be all[$ to occur1 z !y cut away ! metal & score ! surface ( ! commutator4 ,sp>k-tube4 ,a tube us$ z a gauge to det]m9e :5 ! exhau/ion ( ! vacuum *amb]1 or bulb1 ( an inc&esc5t lamp is suffici5tly high4 ,specific ,gravity4 ,! relative weight or d5sity ( a body z comp>$ ) a /&>d4 ,wat] is usually tak5 z a /&>d = solids & liquids1 & air = gases4 ,spe$-c\nt]4 ,an in/rum5t :i* records ! numb] ( revolutions a %aft makes 9 a giv5 "t4 ,sp5t ,acid4 ,acid :i* has become exhau/$4 ,9 a batt]y ! acid becomes sp5t f comb9ation ) z9c2 x also loses its depol>iz+ p[]4 ,spr+-contact4 ,a spr+ connect$ to "o lead ( an electric circuit4 ,x is arrang$ to press aga9/ ano!r spr+ or contact1 :i* x op5s or closes by ! introduction ( a plug or w$ge4 ,spr+-jack4 ,an arrangem5t ( spr+-arm conductors "u :i* plugs ) wires atta*$ c be slipp$ to make a new connection or to cut out c]ta9 circuits4 ,spuri\s ,resi/ance4 7,see ,resi/ance1 ,spuri\s47 ,/&>d ,c&le4 7,see ,c&le1 ,/&>d47 ,/&>d ,resi/ance4 7,see ,resi/ance1 ,/&>d47 ,/>t+-box4 ,a resi/ance or %unt box us$ = lett+ curr5t pass gradually into motors1 in/ead ( ?r[+ on ! full curr5t at once4 ,/atic ,electricity4 ,electricity g5]at$ by friction2 frictional electricity1 su* z lightn+2 electricity ( high electro-motive =ce & practically uncontrollable = comm]cial purposes4 ,/atic ,%ock4 ,a t]m us$ 9 electro-!rapeutics = describ+ ! dis*>ge f a small cond5s] or ,leyd5-j>2 also ! effect produc$ by ! action ( ! vibrator ( ! induction-coil4 ,/ation1 ,c5tral4 ,! build+ or place 9 :i* ! electrical app>atus is in/all$ = ! g5]ation ( curr5t2 ! headqu>t]s ( telephone l9es4 ,/eady ,curr5t4 ,an electric curr5t ^: /r5g? is fix$ or inv>iable4 ,/ock-tick]4 ,an in/rum5t employ$ to give quotations ( /ocks by telegraphic record4 ,a pap] tape runs ?r\gh an electrical ma*9e :i* pr9ts on x ! figures & lett]s t /& = /ocks & _! values4 ,! :ole sy/em is op]at$ f a /ation locat$ 9 ! ,/ock-ex*ange4 ,/orage ,accumulator4 7,see ,accumulator1 ,/orage47 ,/orage-batt]y4 7,see ,batt]y1 ,/orage47 ,/r5g? ( ,curr5t4 ,amp]age2 ! quantity ( curr5t 9 a circuit4 ,/ripp+4 ,! process ( remov+ electro-plat+1 or ?9 metal coat+s1 f an object be=e x is re-electro-plat$4 ,/ripp+ ,liquid4 ,! liquid 9 a /ripp+-ba? us$ = remov+ metals f surfaces be=e re-plat+ !m4 ,subm>9e ,cable4 ,a telegraphic cable laid at ! bottom ( ! sea or any body ( wat]4 ,subm>9e ,se>*-light4 ,an inc&esc5t light :i* works "u wat]4 ,sub-/ation4 ,a g5]at+ or conv]t+ plant subsidi>y to a c5tral /ation1 & plac$ s z to supply curr5t 9 a di/rict situat$ at a di/ance f ! ma9 p[]-h\se4 ,subway1 ,electric4 ,an und]gr\nd passageway utiliz$ = c>ry+ cables & wires4 ,sweat+4 ,a process by :i* ! ends ( cables are br\ght toge!r & sold]$4 ,s-,w-,g4 ,an abbreviation = /&>d wire gauge4 ,swit*4 ,a device = op5+ & clos+ an electric circuit4 ,made 9 a great v>iety ( =ms1 su* z pu%-button1 telegraph-key1 knife swit*1 automatic swit*1 lev] swit*1 rheo/at1 etc4 ,swit*-bell4 ,a comb9$ bell & swit*4 ,! bell is op]at$ :5 ! swit* is op5$ or clos$4 ,swit*-blade4 ,! blade ( a swit*2 a conduct+ /rip connect+ two contact-jaws4 ,swit*-bo>d4 ,a bo>d or table to :i* wires are l$ & connect$ ) cross-b>s or o!r devices by :i* connections c be made4 ,syn*ronize4 ,to agree 9 po9t ( "t2 to effect concurr5ce ( phase 9 two alt]nat+-curr5t ma*9es1 9 ord] to comb9e !m electrically4 ,t ,table-pu%4 ,a pu%-button connect$ ) a call-bell & fix$ on a table = conv5i5ce 9 us+4 ,tamad9e4 ,a =m ( cellulose us$ = mak+ ! filam5ts ( inc&esc5t lamps4 ,! mat]ial is cut into prop] %apes1 c>boniz$1 & fla%$4 ,tang5t ,galvanomet]4 7,see ,galvanomet]1 ,tang5t47 ,tape1 ,insulat+4 ,prep>$ tape us$ 9 cov]+ ! b>$ ends ( wires or jo9ts4 ,tap-wires4 ,! conductors 9 trolley sy/ems t at /at$ int]vals1 take ! curr5t f ! ma9s & supply x to ! b>e fe$-wires4 ,telegraph4 ,a sy/em ( electric communication inv5t$ by ,s4 ,f4 ,b4 ,morse1 9 :i* ! dot-&-da% *>act]s are us$4 ,!re are v>i\s modifications ( ! sy/em--d\ble 7or duplex71 multiplex1 & quadruplex--by means ( :i* a numb] ( messages may be s5t out ov] ! same wires at "o "t4 ,communication f place to place is _h ov] wires m\nt$ on poles1 or by und]gr\nd or subm>9e cables4 ,telegraphy1 ,wireless4 ,a sy/em ( telegraphy c>ri$ on )\t ! aid ( wires1 us+ in/ead ! e!r waves ( ! atmosph]e to conduct ! vibrations ov]head1 & ! gr\nd1 or e>?1 z a return4 ,! pres5t limit ( its work+ is ab\t f\r ?\s& miles4 ,telephone4 ,an in/rum5t & app>atus = ! transmission ( articulate spee* by ! electric curr5t4 ,a magnet is encas$ 9 a tube & is encircl$ at "o end by a coil ( f9e1 insulat$ wire4 ,a diaphragm ( ?9 iron is fix$ 9 front ( ! coil & close to ! end ( ! magnet4 ,! ends ( ! coil-wires are connect$ ) a l9e1 at ! o!r end ( :i* ano!r & simil> in/rum5t is in/all$4 ,! voice causes ! s5d+ diaphragm to vibrate1 & ^! waves are transmitt$ to ! o!r in/rum5t1 :]e !y c be he>d ?r\gh contra-vibrations ( ! receiv+ diaphragm4 ,telephone1 ,long-di/ance4 ,a telephone ( mod]n con/ruction1 9 :i* ! s\nd-record+ me*anism is s s5sitive z to make ! vibrations ( ! voice audible at long di/ances4 ,x w "w satisfactorily at "o ?\s& or ev5 fifte5 hundr$ miles4 ,t]m9al4 ,! end ( any op5 electric circuit1 or ( any electric app>atus1 z ! electrodes ( a batt]y4 ,!rmo/at1 ,electric4 ,an app>atus simil> 9 "s respects to a !rmomet]1 & us$ = clos+ an electric circuit :5 ! latt] becomes heat$4 ,x is us$ 9 connection ) automatic fire-al>ms to give w>n+ ( fire4 ,= ?is purpose ! metal coil is arrang$ to close ! contact at a temp]ature ( #abe ,f4 ,x usually consi/s ( a comp\nd /rip ( metal w\nd 9 ! =m ( a spiral & fa/5$ at "o end4 ,to ?is end "o t]m9al ( a circuit is connect$4 ,! expansion ( ! coil causes its loose end to t\* a contact-po9t & close ! circuit4 ,?ird ,rail4 ,a railway motive sy/em :i* employs a ?ird rail in/ead ( an ov]head trolley fe$-wire4 ,! rail is laid on or "u ! surface ( ! gr\nd & prop]ly insulat$4 ,a %oe f ! c> be>s on ! rail & takes up ! curr5t4 ,?ree-wire ,circuit4 ,a sy/em inv5t$ by ,edison = ! di/ribution1 f two dynamos1 ( curr5t = multiple arc or con/ant pot5tial s]vice4 ,"o wire or lead />ts f ! positive pole ( "o dynamo1 ano!r f ! negative pole ( ! o!r dynamo1 & betwe5 ! two dynamos ! c5tral or neutral lead is made fa/4 ,illu/ration ,n[ ! dynamos may g5]ate a curr5t ( #bbj volts1 & s5d x1 at ?is /r5g?1 ?r\gh ! out] wires2 b if lamps are connect$ betwe5 ei!r ( ! out] & ! neutral wires1 ! curr5t1 pass+ ?r\gh ! lamps1 w be r$uc$ to #aaj volts4 ,"t-ball1 ,electric4 ,a ball :i*1 by means ( electricity1 is made to drop f ! top ( a high pole1 giv+ a visual signal = twelve o'clock or any o!r h\r t may be designat$4 ,traction1 ,electric4 ,! propulsion ( a c> or conveyance by means ( electricity4 ,trans=m]4 ,9 alt]nat+-curr5t sy/ems1 ! induction-coil by means ( :i* ! prim>y curr5t1 ) high initial electro-motive =ce1 is *ang$ into a second>y curr5t ) l[ initial electro-motive =ce4 ,transmission4 ,! conveyance ( electric en]gy & curr5ts f "o po9t to ano!r by ! prop] means ( conduction4 ,transmitt]4 ,an in/rum5t :i* orig9ates ! signals :i* are s5t ?r\gh a l9e or circuit4 ,! ,morse key 9 telegraphy & ! ,blake transmitt] 9 telephony are examples4 ,tri-phase4 ,?ree-phase4 ,trolley4 ,a contact-:eel ( bronze :i* rolls "u ! supply-wire 9 an ov]head traction sy/em & takes (f ! curr5t necess>y to run ! c> motors4 ,trolley-:eel4 ,! same z ,trolley4 ,trolley-wire4 ,! ov]head wire 9 a traction sy/em :i* fe$s ! curr5t ?r\gh a trolley-:eel & pole to ! motors ( a c> runn+ und]nea?4 ,true ,ohm4 7,see ,ohm1 ,true47 ,true ,resi/ance4 7,see ,resi/ance1 ,true47 ,two-wire ,circuit4 ,! s+le sy/em univ]sally us$ = light & p[] transmission ( curr5t4 ,u ,undulat+ ,curr5t4 7,see ,curr5t1 ,undulat+47 ,uni=m ,magnetic ,field4 7,see ,magnetic ,field1 ,uni=m47 ,unipol>4 ,hav+ b "o pole4 ,unit4 ,! s+le /&>d ( =ce1 light1 heat1 magnetism1 attraction1 repulsion1 resi/ance1 etc4 ,v ,vacuum4 ,a space empty or void ( all matt]2 a space f :i* all gases h be5 exhau/$4 ,vacuum ,tubes4 ,tubes ( glass ?r\gh :i* electric dis*>ges are pass$ aft] ! gases h be5 p>tially remov$2 = example1 ! ,x-ray tube ( ,rntg5 & ! ,crooke tubes4 ,vibrator1 ,electro-magnetic4 ,! make-&-break me*anism us$ on induction-coils1 or o!r simil> app>atus1 9 :i*1 ?r\gh alt]nate attractions1 an arm or spr+ is kept 9 motion4 ,vitriol1 ,blue4 ,a trade "n = copp] sulphate4 7,blue/one47 ,vitriol1 ,gre54 ,a trade "n = f]r\s sulphate4 7,copp]as47 ,vitriol1 ,:ite4 ,a trade "n = z9c sulphate4 7,salts ( z9c47 ,volt4 ,! practical unit ( electro-motive =ce2 ! volume & pressure ( an electric curr5t4 ,voltage4 ,electric-motive =ce express$ 9 volts--z1 a voltage ( #ajj volts4 ,voltaic4 ,a t]m d]iv$ f ! "n ( ! ,italian sci5ti/ ,volta1 & us$ 9 _m ways z appli$ to electrical curr5t & devices4 ,=m]ly ! t]m galvanic 0 commonly employ$4 ,voltaic ,electricity4 7,see ,electricity1 ,voltaic47 ,voltimet]4 ,an in/rum5t = measur+ ! voltage ( a curr5t4 ,vulcanite4 ,vulcaniz$ rubb]4 ,valuable = its insulat+ prop]ties & inductive capability4 ,w ,watt4 ,! practical unit ( electrical activity2 ! rate ( "w or rate ( en]gy4 ,x is a unit ( en]gy or ( "w repres5t$ by a curr5t ( "o amp]e urg$ on by "o volt ( electro-motive =ce4 ,! volt-amp]e4 ,! /&>d ( electrical en]gy correspond+ to horse-p[] 9 me*anics4 ,watt-h\r4 ,a unit ( electric en]gy or "w2 "o watt ex]t$ or exp5d$ ?r\gh "o h\r4 ,waves1 ,electro-magnetic4 ,e!r waves caus$ by electro-magnetic di/urbances affect+ ! lum9if]\s e!r4 ,weld+1 ,electric4 ,weld+ by ! use ( ! electric curr5t4 ,wim%ur/ ,electric ,ma*9e4 ,an influ5ce ma*9e = produc+ high pot5tial or /atic electricity4 ,?9 disks ( glass are m\nt$ on insulat$ be>+s & revolv$ by p[]4 ,bru%es collect ! frictional electricity1 :i* is dis*>g$ into a ,leyd5-j> or o!r =m ( accumulator4 ,x is ( no practical use except+ 9 electro-!rapeutics4 ,wire1 ,flexible4 ,a cord ( f9e wire /r&s laid toge!r & insulat$ s t x may be easily b5t or wrapp$4 ,wir+4 ,in/all+ wires s z to =m a circuit = ! conveyance ( curr5t = light1 heat1 & p[]4 ,x ,x-rays4 ,a curi\s ph5om5on involv+ ! radiation ( invisible rays ( light1 :i* h ! p[] to travel ?r\gh v>i\s opaque bodies4 ,! rays are us$ 9 detect+ =eign sub/ances 9 ! human body & = photograph+ invisible or hidd5 objects )\t di/urb+ _! surr\nd+s4 ,x-ray ,lamp4 ,a high vacuum tube lamp ^: int]ior walls are cov]$ ) cry/als ( calcium or o!r fluoresc5t sub/ances1 & :i*1 :5 expos$ to ! ,x-rays1 give out a lum9\s light4 ,y ,yoke4 ,a piece ( s(t iron :i* connects ! ends ( two portions ( a core on :i* wire coils are w\nd4 ,x is locat$ at ! ends f>!/ f ! poles4 ,! s(t-iron b> plac$ across ! ends ( a horse%oe magnet to reta9 its magnetism4 ,z ,z9c-batt]y4 ,a batt]y :i* decomposes z9c 9 an electrolyte1 !reby produc+ a curr5t4 ,z9c ,curr5ts4 ,negative curr5ts4 ,z9c-plat+4 ,! employm5t ( z9c 9 electro-plat+4 ,,! ,,end ,transcrib]'s ,notes ,inconsi/5t spell+1 hyph5ation1 etc4 h be5 reta9$1 unless m5tion$ "u ,*anges ,made bel[4 ,te*nical descriptions h be5 kept z pr9t$1 ev5 :5 !y seem d\btful1 wrong or dang]\s4 ,dep5d+ on ! h>d- & s(tw>e & _! sett+s us$ to read ?is text1 n all elem5ts may display z int5d$4 ,*anges ,made ,footnotes & illu/rations h be5 mov$ outside text p>agraphs4 ,:]e lett]s 7su* z ,v or ,l7 are us$ to d5ote a %ape r ?an ! lett]1 !y h be5 transcrib$ z ,v or ,l = consi/5cy ) o!r1 simil>ly us$ lett]s su* z ,u4 ,"s m9or obvi\s typographical errors h be5 correct$ sil5tly4 ,page #ajh3 call$ ,nobile's pair *ang$ to call$ ,nobili's pair4 ,page #ahb3 %allack$ *ang$ to %ellack$4 ,page #ahd3 7,a1 ,b1 & ,c7 & ,a ,a1 ,b ,b1 & ,c ,c7 *ang$ to 7,a1 ,b1 & ,c & ,a ,a1 ,b ,b1 & ,c ,c74 ,diction>y3 sev]al entries h be5 mov$ to _! prop] alphabetical position4 ,page #ccd3 mod]n applications ( ph5onema *ang$ to applications ( ph5om5a ,page #cgb3 ,coil1 ,ruhmk(f *ang$ to ,coil1 ,ruhmkorff4 ,page #chb3 ,daniells *ang$ to ,daniell4 ,page #cif3 graphite a native2 =m ( c>bon *ang$ to graphite2 a native =m ( c>bon4 ,page #dja3 ,ruhmk(f ,coil4 7,see ,coil1 ,ruhmk(f47 *ang$ to ,ruhmkorff ,coil4 7,see ,coil1 ,ruhmkorff47