file :i* includes ! orig9al illu/rations4 ,see #ddffe-;h4htm or #ddffe-;h4zip3 7https3_/_/www4gut5b]g4org_/ca*e_/epub_/ #ddffe_/pg#ddffe-;images4html7 or 7https3_/_/www4gut5b]g4org_/files_/#ddff e_/ddffe-;h4zip7 ,images ( ! orig9al pages are available ?r\gh ,int]net ,ar*ive4 ,see https3_/_/ar*ive4org_/details_/?+sboy%\l dk#jj/jo ,transcrib]'s note3 ,text enclos$ by und]scores is 9 italics 7italics74 ,text enclos$ by equal signs is 9 bold face 7bold74 ,*>act]s enclos$ by curly brackets aft] an und]score are subscripts 7example3 ,cu,s,o#d ! *emical =mula ( copp] sulfate74 ,,?+s ,a ,,boy ,,%\ld ,,"k ,,ab\t ,,electricity ,illu/ration 99 99 99 99 99 ,,by ,,! ,,same ,,au?or4 ,,fun ,,) ,,magnetism4 ,a book & complete outfit ( app>atus = ,sixty-,"o ,exp]im5ts4 ,,fun ,,) ,,electricity4 ,a book & complete outfit ( app>atus = ,sixty ,exp]im5ts4 ,,fun ,,) ,,puzzles4 ,a book1 key & complete outfit = ,f\r ,hundr$ ,puzzles4 ,,fun ,,) ,,soap-,,bubbles4 ,a book & complete outfit ( app>atus = ,fancy ,bubbles & ,films4 ,,fun ,,) ,,%ad[s4 ,includ+ book ( in/ructions ) "o hundr$ illu/rations & a complete outfit ( app>atus = ,%ad[ ,pictures1 ,pantomimes1 ,ent]ta9m5ts1 etc41 etc4 ,,hu/le-,,ball4 ,an ,am]ican game4 ,play$ by means ( magic w&s & poli%$ balls ( /eel4 ,,j+o4 ,! great w> game1 includ+ ,,j+o ,,junior4 ,,h[ ,,two ,,boys ,,made ,,_! ,,own ,,electrical ,,app>atus4 ,a book conta9+ complete directions = mak+ all k9ds ( simple app>atus = ! /udy ( elem5t>y electricity4 ,,! ,,/udy ,,( ,,elem5t>y ,,electricity ,,& ,,magnetism ,,by ,,exp]im5t4 ,?is book is design$ z a text-book = amateurs1 /ud5ts1 & o!rs :o wi% to take up a sy/ematic c\rse ( simple exp]im5ts at home or 9 s*ool4 ,,?+s ,a ,,boy ,,%\ld ,,"k ,,ab\t ,,electricity4 ,?is book expla9s1 9 simple1 /raight=w>d language1 _m ?+s ab\t electricity2 ?+s 9 :i* ! ,am]ican boy is int5sely int]e/$2 ?+s he wants to "k2 ?+s he %\ld "k4 ,,ans41 ,,or ,,accuracy1 ,,neatness ,,& ,,spe$4 ,= tea*]s & pupils4 ,conta9+ /udy-*>ts1 practice devices & special me?ods = accurate1 rapid "w ) figures4 ,ask ,y\r ,booksell]1 ,/ation]1 or ,toy ,deal] = our ,books1 ,games1 ,puzzles1 ,educational ,amusem5ts1 ,etc4 ,,catalogue ,,^u ,,application ,?omas ,m4 ,/4 ,john1 #djg ,we/ #ea/ ,/41 ,new ,york4 99 99 99 99 99 ,,?+s ,a ,,boy ,,%\ld ,,"k ,,ab\t ,,electricity by ,,?omas ,m4 ,,/4 ,,john1 ,met4 ,e4 ,au?or ( ,fun ,) ,magnetism1 ,fun ,) ,electricity1 ,h[ ,two ,boys ,made ,_! ,own ,electrical ,app>atus1 ,! ,/udy ( ,elem5t>y ,electricity & ,magnetism by ,exp]im5t1 etc4 ,,second ,,edition ,illu/ration ,new ,york ,?omas ,m4 ,/4 ,john #djg ,we/ #ea/ ,/reet #aijc ,copyright1 #aijj4 ,by ,?omas ,m4 ,/4 ,john4 ,,?+s ,a ,,boy ,,%\ld ,,"k ,,ab\t ,,electricity ,,table ,,( ,,cont5ts ,,*apt] ,,page ,i4 ,ab\t ,frictional ,electricty #g ,,ii4 ,ab\t ,magnets & ,magnetism #ba ,,iii4 ,h[ ,electricity is ,g5]at$ by ! ,voltaic ,cell1 #cb ,,iv4 ,v>i\s ,voltaic ,cells1 #cf ,v4 ,ab\t ,pu%-,buttons1 ,swit*es & ,b9d+-,po/s1 #dc ,,vi4 ,units & ,app>atus = ,electrical ,measurem5ts1 #dh ,,vii4 ,*emical ,effects ( ! ,electric ,curr5t1 #eh ,,viii4 ,h[ ,electroplat+ & ,electrotyp+ are ,done1 #fj ,,ix4 ,! ,/orage ,batt]y1 & ,h[ x ,works1 #fc ,x4 ,h[ ,electricity is ,g5]at$ by ,heat1 #fh ,,xi4 ,magnetic ,effects ( ! ,electric ,curr5t1 #ga ,,xii4 ,h[ ,electricity is ,g5]at$ by ,induction1 #gg ,,xiii4 ,h[ ! ,induction ,coil ,works1 #hj ,,xiv4 ,! ,electric ,telegraph1 & ,h[ x ,s5ds ,messages1 #hd ,,xv4 ,! ,electric ,bell & ,"s ( its ,uses1 #ia ,,xvi4 ,! ,telephone & ,h[ x ,transmits ,spee*1 #ie ,,xvii4 ,h[ ,electricity is ,g5]at$ by ,dynamos1 #aja ,,xviii4 ,h[ ! ,electric ,curr5t is ,trans=m$1 #aji ,,xix4 ,h[ ,electric ,curr5ts are ,di/ribut$ = ,use1 #aad ,,xx4 ,h[ ,heat is ,produc$ by ! ,electric ,curr5t1 #abd ,,xxi4 ,h[ ,light is ,produc$ by ! ,inc&esc5t ,lamp1 #abi ,,xxii4 ,h[ ,light is ,produc$ by ! ,arc ,lamp1 #ace ,,xxiii4 ,x-,rays1 & ,h[ ! ,bones ( ! ,human ,body are ,photograph$1 #ada ,,xxiv4 ,! ,electric ,motor1 & ,h[ x ,does ,"w1 #adg ,,xxv4 ,electric ,c>s1 ,boats & ,automobiles1 #aed ,,xxvi4 ,a ,^w ,ab\t ,c5tral ,/ations1 #afb ,,xxvii4 ,miscellane\s ,uses ( ,electricity1 #afe ,,to ,,! ,,read] ,= ! b5efit ( ^? :o wi% to make _! own electrical app>atus = exp]im5tal purposes1 ref]5ces h be5 made ?r\gh\t ?is "w to ! ,app>atus ,book2 by ?is is meant ! au?or's ,h[ ,two ,boys ,made ,_! ,own ,electrical ,app>atus4 ,= ^? :o wi% to take up a c\rse ( elem5t>y electrical exp]im5ts t c be p]=m$ ) simple1 home-made app>atus1 ref]5ces h be5 made to ,/udy2 by ?is is meant ,! ,/udy ( ,elem5t>y ,electricity & ,magnetism by ,exp]im5t4 ,,! ,,au?or4 ,?+s ,a ,boy ,%\ld ,"k ,ab\t ,electricity ,,*apt] ,i4 ,,ab\t ,,frictional ,,electricity4 #a4 ,"s ,simple ,exp]im5ts4 ,h y ev] %uffl$ y\r feet along ov] ! c>pet on a w9t]'s ev5+ & !n quickly t\*$ y\r f+] to ! nose ( an unsuspect+ fri5d8 ,did he jump :5 a bright sp>k leap$ f y\r f+] & /ruck him fairly on ! v tip ( 8 s5sitive nasal organ8 ,illu/ration3 ,fig4 #a4 ,did y ev] succe$ 9 prov+ to ! pussy-cat1 ,fig4 #a1 t some?+ unusual occurs :5 y ?or\ghly rub 8 w>m fur ) y\r h&8 ,did y notice ! bright sp>ks t pass$ to y\r h& :5 x 0 held j above ! cat's back8 ,y %\ld be able to see1 he>1 & feel ^! sp>ks1 especially :5 ! air is dry & y are 9 a d>k room4 ,did y ev] heat a piece ( pap] be=e ! fire until x 0 real hot1 !n lay x ^u ! table & rub x f end to end ) y\r h&1 & f9ally see x cl+ to ! wall8 ,7 y ev] 9 a factory :]e !re 7 l>ge belts runn+ rapidly ov] pulleys or :eels1 & :]e l>ge sp>ks w\ld jump to y\r h&s :5 held ne> ! belts8 ,if y h nev] p]=m$ any ( ! f\r exp]im5ts m5tion$1 y %\ld try !m ! fir/ "t a *ance occurs4 ,!re are doz5s ( simple1 fasc9at+ exp]im5ts t may be p]=m$ ) ?is k9d ( electricity4 #b4 ,"n4 ,z ?is v>iety ( electricity is made1 or g5]at$1 by ! friction ( sub/ances ^u ea* o!r1 x is call$ frictional electricity4 ,x is also call$ /atic electricity1 because x g5]ally /&s /ill ^u ! surface ( bodies & does n fl[ 9 curr5ts z easily z "s ( ! o!r v>ieties4 ,/atic electricity may be produc$ by induction z well z by friction4 ,illu/ration3 ,fig4 #b4 #c4 ,hi/ory4 ,x has be5 kn[n = ov] #b1jjj ye>s t c]ta9 sub/ances act que]ly :5 rubb$4 ,amb] 0 ! fir/ sub/ance ^u :i* electricity 0 produc$ by friction1 & z ! ,greek "n = amb] is elektron1 bodies s affect$ 7 said to be electrifi$4 ,:5 a body1 l ebonite1 is rubb$ ) a flannel clo?1 we say t x becomes *>g$ ) electricity4 ,j :at happ5s to ! ebonite is n cle>ly und]/ood4 ,we "k1 h[ev]1 t x w attract light bodies1 & !n quickly repel !m if !y be conductors4 ,fig4 #b %[s a piece ( tissue-pap] jump+ t[>d a %eet ( ebonite t has be5 electrifi$ ) a flannel clo?4 #d4 ,conductors & ,non-,conductors4 ,electricity c be produc$ ^u glass & ebonite because !y d n c>ry or conduct x away4 ,if a piece ( iron be rubb$1 ! electricity passes f ! iron into ! e>? z fa/ z x is g5]at$1 because ! iron is a conductor ( electricity4 ,glass is an insulator or non-conductor4 ,frictional electricity resides ^u ! outside1 only1 ( conductors4 ,a holl[ t9 box w hold z great a *>ge z a solid piece ( metal hav+ ! same outside size & %ape4 ,:5 frictional electricity passes f "o place to ano!r1 sp>ks are produc$4 ,lightn+ is caus$ by ! passage ( /atic electricity f a cl\d to ! e>?1 or f "o cl\d to ano!r4 ,9 ?is case air =ms ! conductor4 7,= exp]im5ts1 see ,/udy1 ,*apt] ,,vii47 ,illu/ration3 ,fig4 #c4 #e4 ,electroscopes4 ,a piece ( c>bon1 pi?1 or ev5 a small piece ( damp tissue-pap] w s]ve z an electroscope to te/ ! pres5ce ( /atic electricity4 ,! pi? is usually ti$ to a piece ( silk ?read :i* is a non-conductor4 ,fig4 #c %[s ! ord9>y =m ( pi?-ball electroscope4 ,! leaf electroscope is a v delicate app>atus4 ,gold-leaf is g5]ally us$1 b alum9um-leaf w /& h&l+ & w d = all ord9>y purposes4 ,fig4 #d %[s a common =m1 ! glass be+ us$ to keep curr5ts ( air f ! leaves & at ! same "t to insulate !m f ! e>?4 ,electroscopes are us$ to %[ ! pres5ce1 relative am\nt1 or k9d ( /atic electricity on a body4 7,see ,/udy1 ,*apt] ,,xi47 ,illu/ration3 ,fig4 #d4 #f4 ,two ,k9ds ( ,electrification4 ,x c be %[n t ! electrification produc$ on all bodies by friction is n ! same2 = example1 t g5]at$ ) glass & silk is n ! same z t made ) ebonite & flannel4 ,x has be5 agre$ to call t produc$ by glass & silk positive1 & t by ebonite & flannel negative4 ,! signs & - are us$ = positive & negative4 #g4 ,laws ( ,electrification4 7#a7 ,*>ges ( ! same k9d repel ea* o!r2 7#b7 *>ges ( unlike k9ds attract ea* o!r2 7#c7 ei!r k9d ( a *>ge attracts & is attract$ by a neutral body4 #h4 ,/atic ,electric ,ma*9es4 ,9 ord] to produce /atic electricity 9 quantities = exp]im5ts1 "s device is necess>y4 ,! electrophorus 7e-lec-troph-o-rus7 is ab\t ! simple/ =m ( ma*9e4 ,fig4 #e %[s a simple electrophorus 9 :i* are two insulators & "o conductor4 ,! ebonite %eet ,e ,s is us$ ) a flannel clo? to g5]ate ! electricity4 ,! metal cov] ,e ,c is lift$ by ! insulat+ h&le ,e ,r4 ,! cov] ,e ,c is plac$ ^u ! ?or\ghly *>g$ %eet ,e ,s1 & !n x is t\*$ = an in/ant ) ! f+]1 be=e lift+ x by ,e ,r4 ,! *>ge ^u ,e ,c c !n be remov$ by br++ ! h& ne> x4 ,! bright sp>k t passes f ,e ,c to ! h& indicates t ,e ,c has dis*>g$ itself into ! e>?4 ,! action ( ! electrophorus dep5ds ^u induction4 7,= exp]im5ts1 details ( action1 induc$ electrification1 etc41 see ,! ,/udy ( ,elem5t>y ,electricity & ,magnetism by ,exp]im5t1 ,*apt]s ,,viii4 & ,,ix47 ,illu/ration3 ,fig4 #e4 ,! fir/ electric ma*9e consi/$ ( a ball ( sulphur fa/5$ to a sp9dle :i* c\ld be turn$ by a crank4 ,by hold+ ! h&s or a pad ( silk ^u ! revolv+ ball1 electricity 0 produc$4 ,illu/ration3 ,fig4 #f4 ,illu/ration3 ,fig4 #g4 #i4 ,! ,cyl9d] ,electric ,ma*9e consi/s1 z %[n 9 ,fig4 #f1 ( a glass cyl9d] s m\nt$ t x c be turn$ by a crank4 ,friction is produc$ by a pad ( lea!r ,c1 :i* presses aga9/ ! cyl9d] z x turns4 ,electric sp>ks c be tak5 f ! l>ge conductors :i* are insulat$ f ! e>?4 ,! opposite electricities unite ) sp>ks across ,d & ,e4 ,if use is to be made ( ! electricity1 ei!r ! rubb] or ! prime conductor mu/ be connect$ ) ! gr\nd4 ,9 ! =m] case positive electricity is obta9$2 9 ! latt]1 negative4 #aj4 ,! ,plate ,electrical ,ma*9e4 ,fig4 #g also %[s an old =m ( ma*9e4 ,su* ma*9es are made ( circul> plates ( glass or ebonite1 two rubb+ pads be+ usually employ$1 "o on ea* side ( ! plate4 ,"o op]ator is se5 on an insulat$ /ool 7,fig4 #g71 ! electricity pass+ ?r\gh him be=e ent]+ ! e>? by way ( ! body ( ! man at ! "r4 ,illu/ration3 ,fig4 #h4 #aa4 ,! ,toepl]-,holtz ,ma*9e1 9 "o =m1 is %[n 9 ,fig4 #h4 ,! electricity is produc$ by ! pr9ciple ( induction1 & n by m]e friction4 ,?is ma*9e1 us$ 9 connection ) cond5s]s1 produces l>ge sp>ks4 #ab4 ,! ,wim%ur/ ,ma*9e is ( rec5t date1 & n be+ easily affect$ by atmosph]ic *anges1 is v useful = ord9>y laboratory "w4 ,fig4 #i %[s "o =m ( ?is ma*9e4 #ac4 ,influ5ce ,ma*9es = ,m$ical ,purposes are made 9 a l>ge v>iety ( =ms4 ,a ,wim%ur/ ma*9e is g5]ally us$ z an excit] to *>ge ! plates ( ! l>ge ma*9e :5 !y lose _! *>ge on acc\nt ( excessive moi/ure 9 ! atmosph]e4 ,fig4 #aj %[s a l>ge ma*9e4 ,illu/ration3 ,fig4 #i4 #ad4 ,uses ( ,electrical ,ma*9es4 ,/atic electricity has be5 us$ = _m ye>s 9 ! laboratory = exp]im5tal purposes1 = *>g+ cond5s]s1 = m$ical purposes1 etc4 ,x is n[ be+ us$ = ,x-ray "w1 & consid]able advancem5t has be5 made )9 a few ye>s 9 ! con/ruction & effici5cy ( ! ma*9es4 ,illu/ration3 ,fig4 #aj4 ,) ! mod]n ma*9es l>ge sp>ks are produc$ by m]ely turn+ a crank1 en\gh electricity be+ produc$ to imitate a small ?und]/orm4 ,! sp>ks ( home-made lightn+ w jump sev]al in*es4 ,d n ?9k t electricity is g5]at$ 9 a comm]cial way by /atic electric ma*9es4 ,! practical uses ( /atic electricity are v few :5 comp>$ ) ^? ( curr5t electricity f batt]ies & dynamos4 #ae4 ,cond5sation ( ,/atic ,electricity4 ,by means ( app>atus call$ cond5s]s1 a t]rific *>ge ( /atic electricity may be /or$4 ,fig4 #aa %[s ! mo/ common =m ( cond5s]1 kn[n z ! ,leyd5 j>4 ,x consi/s ( a glass j> ) an inside & outside coat+ ( t9-foil4 ,illu/ration3 ,fig4 #aa4 ,illu/ration3 ,fig4 #ab4 ,to *>ge ! j> x is held 9 ! h& s t ! outside coat+ %all be connect$ ) ! e>?1 ! sp>ks f an electric ma*9e be+ pass$ to ! knob at ! top1 :i* is connect$ by a *a9 to ! inside coat+4 ,to dis*>ge ! j>1 ,fig4 #ab1 a conductor ) an insulat+ h&le is plac$ aga9/ ! outside coat2 :5 ! o!r end ( ! conductor is swung ov] t[>ds ! knob1 a bright sp>k passes betwe5 !m4 ,?is device is call$ a dis*>g]4 ,fig4 #ac %[s a dis*>ge ?r\gh e!r :i* ! sp>k ignites4 ,illu/ration3 ,fig4 #ac4 #af4 ,! ,leyd5 ,batt]y1 ,fig4 #ad1 consi/s ( sev]al j>s connect$ 9 su* a way t ! area ( ! inn] & out] coat+s is greatly increas$4 ,! batt]y has a l>g] capacity ?an "o ( its j>s4 7,= ,exp]im5ts 9 ,cond5sation1 see ,/udy1 ,*apt] ,x47 ,illu/ration3 ,fig4 #ad4 #ag4 ,electromotive ,=ce ( ,/atic ,electricity4 ,al?\gh ! sp>ks ( /atic electricity are l>ge1 ! quantity ( electricity is v small4 ,x w\ld take ?\s&s ( galvanic cells to produce a sp>k an in* long4 ,:ile ! quantity ( /atic electricity is small1 its pot5tial1 or electromotive =ce 7,e4 ,m4 ,f471 is v high4 ,we say t an ord9>y gravity cell has an ,e4 ,m4 ,f4 ( a little ov] "o volt4 ,five su* cells jo9$ 9 ! prop] way w\ld h an ,e4 ,m4 ,f4 ( a little ov] five volts4 ,y w und]/&1 !n1 :at is meant :5 we say t ! ,e4 ,m4 ,f4 ( a lightn+ fla% is millions ( volts4 #ah4 ,atmosph]ic ,electricity4 ,! air is usually electrifi$1 ev5 9 cle> wea!r1 al?\gh its cause is n ?or\ghly und]/ood4 ,9 #ageb x 0 prov$ by ,b5jam9 ,frankl9 7,fig4 #ae71 ) 8 fam\s kite exp]im5t1 t atmosph]ic & frictional electricities are ( ! same nature4 ,by means ( a kite1 ! /r+ be+ wet by ! ra91 he succe$$1 dur+ a ?und]/orm1 9 draw+ sp>ks1 *>g+ cond5s]s1 etc4 ,illu/ration3 ,fig4 #ae4 ,illu/ration3 ,fig4 #af4 #ai4 ,lightn+ may be produc$ by ! passage ( electricity betwe5 cl\ds1 or betwe5 a cl\d & ! e>? 7,fig4 #af71 :i*1 ) ! int]v5+ air1 h ! effect ( a cond5s]4 ,:5 ! attraction betwe5 ! two electrifications gets great en\gh1 a sp>k passes4 ,:5 ! sp>k has a zigzag motion x is call$ *a9 lightn+4 ,9 hot wea!r fla%es are (t5 se5 :i* light :ole cl\ds1 no ?und] be+ he>d4 ,?is is call$ heat lightn+1 & is g5]ally consid]$ to be due to di/ant dis*>ges1 ! light ( :i* is reflect$ by ! cl\ds4 ,! lightn+ fla% repres5ts billions ( volts4 ,illu/ration3 ,fig4 #ag4 #bj4 ,?und] is caus$ by ! viol5t di/urbances produc$ 9 ! air by lightn+4 ,cl\ds1 hills1 etc41 produce e*oes1 :i*1 ) ! orig9al s\nd1 make ! roll+ effect4 #ba4 ,lightn+-,rods1 :5 well con/ruct$1 (t5 prev5t viol5t dis*>ges4 ,_! po9t$ prongs at ! top all[ ! negative electricity ( ! e>? to pass quietly into ! air to neutralize ! positive 9 ! cl\d above4 ,9 case ( a dis*>ge1 or /roke ( lightn+1 ! rods aid 9 conduct+ ! electricity to ! e>?4 ,! ends ( ! rods are plac$ deep 9 ! e>?1 ,fig4 #ag4 #bb4 ,/4 ,elmo's ,fire4 ,electrification f ! e>? is (t5 drawn up f ! e>? ?r\gh ! ma/s ( %ips1 ,fig4 #ah1 to neutralize t 9 ! cl\ds1 &1 z x escapes f ! po9ts ( ! ma/s1 light is produc$4 ,illu/ration3 ,fig4 #ah4 #bc4 ,aurora ,borealis1 also call$ ,nor!rn ,lights1 are lum9\s effects1 ,fig4 #ai1 (t5 se5 9 ! nor?4 ,!y (t5 occur at ! same "t ) magnetic /orms1 :5 telegraph & telephone "w may be di/urb$4 ,! exact cause ( ?is light is n kn[n1 b x is ?\ght by _m to be due to di/urbances 9 ! e>?'s magnetism caus$ by ! action ( ! sun4 ,illu/ration3 ,fig4 #ai4 ,,*apt] ,,ii4 ,,ab\t ,,magnets ,,& ,,magnetism4 #bd4 ,natural ,magnets4 ,hundr$s ( ye>s ago x 0 discov]$ t a c]ta9 ore ( iron1 call$ lode/one1 _h ! p[] ( pick+ up small pieces ( iron4 ,x 0 us$ to indicate ! nor? & s\? l9e1 & x 0 discov]$ lat] t small pieces ( /eel c\ld be p]man5tly magnetiz$ by rubb+ !m ^u ! lode/one4 #be4 ,artificial ,magnets4 ,pieces ( /eel1 :5 magnetiz$1 are call$ artificial magnets4 ,!y are made 9 _m =ms4 ,! electromagnet is also an artificial magnet2 ?is w be treat$ sep>ately4 ,illu/ration3 ,fig4 #bj #bf4 ,! ,horse%oe ,magnet1 ,fig4 #bj1 is1 h[ev]1 ! "o ) :i* we are ! mo/ famili>4 ,!y are always pa9t$ r$1 b ! r$ pa9t has no?+ to d ) ! magnetism4 ,! little end-piece is call$ ! keep]1 or armature2 x %\ld always be kept 9 place :5 ! magnet is n 9 use4 ,! magnet itself is made ( /eel1 :ile ! armature is made ( s(t iron4 ,/eel reta9s magnetism = a long "t1 :ile s(t iron loses x almo/ in/antly4 ,! ends ( ! magnet are call$ its poles1 & ne>ly all ! /r5g? ( ! magnet seems to reside at ! poles1 ! curv$ "p hav+ no attraction = outside bodies4 ,"o ( ! poles ( ! magnet is m>k$ ) a l9e1 or ) ! lett] ,n4 ,?is is call$ ! nor? pole ( ! magnet1 ! o!r be+ its s\? pole4 ,illu/ration3 ,fig4 #ba4 #bg4 ,b> ,magnets are /raight magnets4 ,fig4 #ba %[s a r\nd b> magnet4 ,! screw 9 ! end is = use 9 ! telephone1 describ$ lat]4 #bh4 ,comp\nd ,magnets4 ,:5 sev]al ?9 /eel magnets are rivet$ toge!r1 a comp\nd magnet is =m$4 ,^! c be made ) consid]able /r5g?4 ,fig4 #bb %[s a comp\nd horse%oe magnet4 ,fig4 #bc %[s a =m ( comp\nd b> magnet us$ 9 telephones4 ,! use ( ! coil ( wire w be expla9$ lat]4 ,a ?ick piece ( /eel c n be magnetiz$ ?r\gh & ?r\gh4 ,9 ! comp\nd magnet we h ! effect ( a ?ick magnet practically magnetiz$ ?r\gh & ?r\gh4 ,illu/ration3 ,fig4 #bb4 ,illu/ration3 ,fig4 #bc4 #bi4 ,magnetic & ,diamagnetic ,bodies4 ,iron1 & sub/ances conta9+ iron1 are ! ones mo/ readily attract$ by a magnet4 ,iron is said to be magnetic4 ,"s sub/ances1 l nickel1 = example1 are visibly attract$ by v /rong magnets only4 ,/range z x may seem1 "s sub/ances are actually repell$ by /rong magnets2 ^! are call$ diamagnetic bodies4 ,brass1 copp]1 z9c1 etc41 are n visibly affect$ by a magnet4 ,magnetism w act ?r\gh pap]1 glass1 copp]1 lead1 etc4 ,illu/ration3 ,fig4 #bd4 #cj4 ,mak+ ,magnets4 ,"o ( ! /range/ prop]ties t a magnet has is its p[] to give magnetism to ano!r piece ( /eel4 ,if a sew+-ne$le be prop]ly rubb$ ^u "o ( ! poles ( a magnet1 x w become /rongly magnetiz$ & w reta9 its magnetism = ye>s4 ,/rong p]man5t magnets are made ) ! aid ( electromagnets4 ,any numb] ( little magnets may be made f a horse%oe magnet )\t injur+ x4 ,illu/ration3 ,fig4 #be4 #ca4 ,magnetic ,ne$les & ,compasses4 ,if a b> magnet be susp5d$ by a /r+1 or float$ ^u a cork1 :i* c easily be done ) ! magnet made f a sew+-ne$le1 ,fig4 #bd1 x w sw+ ar\nd until its poles po9t nor? & s\?4 ,su* an arrangem5t is call$ a magnetic ne$le4 ,9 ! regul> compass1 a magnetic ne$le is support$ ^u a pivot4 ,compasses h be5 us$ = _m c5turies by m>9]s & o!rs4 ,fig4 #be %[s an ord9>y pocket compass1 & ,fig4 #bf a =m ( m>9]'s compass1 9 :i* ! small b> magnets are fa/5$ to a c>d :i* floats1 ! :ole be+ s m\nt$ t x keeps a horizontal position1 ev5 ?\gh ! vessel rocks4 ,illu/ration3 ,fig4 #bf4 #cb4 ,action ( ,magnets ,^u ,ea* ,o!r4 ,by mak+ two small sew+-ne$le magnets1 y c easily /udy ! laws ( attraction & repulsion4 ,by br++ ! two nor? poles1 or ! two s\? poles1 ne> ea* o!r1 a repulsion w be notic$4 ,unlike poles attract ea* o!r4 ,! attraction betwe5 a magnet & iron is mutual2 t is1 ea* attracts ! o!r4 ,ei!r pole ( a magnet attracts s(t iron4 ,9 magnetiz+ a ne$le1 ei!r end may be made a nor? pole at w2 9 fact1 ! poles ( a weak magnet c easily be rev]s$ by prop]ly rubb+ x ^u a /rong] magnet4 #cc4 ,!ory ( ,magnetism4 ,ea* little p>ticle ( a piece ( /eel or iron is suppos$ to be a magnet1 ev5 be=e x t\*es a magnet4 ,:5 ^! little magnets are ?or\ghly mix$ up 9 ! /eel1 !y pull 9 all sorts ( directions ^u ea* o!r & t5d to keep ! /eel f attract+ outside bodies4 ,:5 a magnet is prop]ly rubb$ ^u a b> ( /eel1 ! nor? poles ( ! little molecul> magnets ( ! /eel are all made to po9t 9 ! same direction4 ,z ! nor? poles help ea* o!r1 ! :ole b> c attract outside bodies4 ,by j>r+ a magnet its molecules are ?or\ghly %ak5 up2 9 fact1 mo/ ( ! magnetism c be knock$ out ( a weak magnet by hamm]+ x4 #cd4 ,ret5tivity4 ,! p[] t a piece ( /eel has to hold magnetism is call$ ret5tivity4 ,diff]5t k9ds ( /eel h diff]5t ret5tivities4 ,a sew+-ne$le ( good /eel w reta9 magnetism = ye>s1 & x is almo/ impossible to knock ! magnetism out by hamm]+ x4 ,s(t /eel has v little ret5tivity1 because x does n conta9 mu* c>bon4 ,s(t iron1 :i* conta9s less c>bon ?an /eel1 holds magnetism v poorly2 s x is n us$ = p]man5t magnets4 ,a little magnetism1 h[ev]1 w rema9 9 ! s(t iron aft] x is remov$ f a magnet4 ,?is is call$ residual magnetism4 #ce4 ,heat & ,magnetism4 ,/eel w completely lose its magnetism :5 heat$ to r$ness1 & a magnet w n attract r$-hot iron4 ,! molecules ( a piece ( r$-hot iron are 9 su* a /ate ( rapid vibration t !y refuse to be br\ght into l9e by ! magnet4 #cf4 ,induc$ ,magnetism4 ,a piece ( s(t iron may be induc$ to become a magnet by hold+ x ne> a magnet1 absolute contact n be+ necess>y4 ,:5 ! s(t iron is remov$1 aga91 f ! influ5ce ( ! magnet1 its magnetism ne>ly all disappe>s4 ,x is said to h tempor>y magnetism2 x _h induc$ magnetism4 ,if a piece ( s(t iron be held ne> ! nor? pole ( a magnet1 z 9 ,fig4 #bg1 poles w be produc$ 9 ! s(t iron1 ! "o ne>e/ ! magnet be+ ! s\? pole1 & ! o!r ! nor? pole4 ,illu/ration3 ,fig4 #bg4 ,illu/ration3 ,fig4 #bh4 #cg4 ,magnetic ,field4 ,if a b> magnet be laid ^u ! table1 & a compass be mov$ ab\t x1 ! compass-ne$le w be attract$ by ! magnet1 & x w po9t 9 a diff]5t direction = e position giv5 to ! compass4 ,?is /range p[]1 call$ magnetism1 rea*es out on all sides ( a magnet4 ,! magnet may be said to act by induction ^u ! compass-ne$le4 ,! space ar\nd ! magnet1 9 :i* ?is inductive action takes place1 is call$ ! magnetic field4 ,fig4 #bh %[s "s ( ! positions tak5 by a compass-ne$le :5 mov$ ab\t on "o side ( a b> magnet4 ,illu/ration3 ,fig4 #bi4 ,illu/ration3 ,fig4 #cj4 #ch4 ,magnetic ,figures c be made by spr9kl+ iron fil+s ^u a %eet ( pap] "u :i* is plac$ a magnet4 ,fig4 #bi %[s a magnetic figure made ) an ord9>y b> magnet4 ,! magnet 0 plac$ ^u ! table & ov] ?is 0 laid a piece ( smoo? pap]4 ,f9e iron fil+s 7 sift$ ^u ! pap]1 :i* 0 g5tly tapp$ s t ! fil+s c\ld arrange !mselves4 ,z ea* p>ticle ( iron became a little magnet1 by induction1 its poles 7 attract$ & repell$ by ! magnet2 & :5 ! pap] 0 tapp$ !y swung ar\nd to _! f9al positions4 ,notice t ! fil+s h arrang$ !mselves 9 l9es4 ,^! l9es %[ ! positions ( "s ( ! l9es ( magnetic =ce :i* surr\nd$ ! magnet4 ,^! l9es ( =ce pass f ! nor? pole ( a magnet ?r\gh ! air on all sides to its s\? pole4 ,illu/ration3 ,fig4 #ca4 ,fig4 #cj %[s a magnetic figure made f two b> magnets plac$ side by side1 _! unlike poles be+ next to ea* o!r4 ,fig4 #ca %[s ! magnetic figure ( a horse%oe magnet ) r\nd poles1 ! poles be+ upp]mo/4 #ci4 ,! ,use ( ,armatures4 ,a magnet attracts iron mo/ /rongly at its poles1 because x is at ! poles t ! greate/ numb] ( l9es ( =ce pass into ! air4 ,l9es ( =ce pass easily ?r\gh s(t iron1 :i* is said to be a good conductor ( !m4 ,air is n a good conductor ( ! l9es ( =ce2 9 ord]1 !n1 = ! l9es ( =ce to pass f ! nor? pole ( a magnet to its s\? pole1 !y mu/ ov]come ?is resi/ance ( ! air1 unless ! armature is 9 place4 ,a magnet w gradually gr[ weak] :5 its armature is left (f4 #dj4 ,t]re/rial ,magnetism4 ,z ! compass-ne$le po9ts to ! nor? & s\?1 ! e>? mu/ act l a magnet4 ,!re is a place v f> nor?1 ab\t a ?\s& miles f ! nor? pole ( ! e>?1 :i* is call$ ! e>?'s nor? magnetic pole4 ,compass-ne$les po9t to ?is place1 & n to ! e>?'s real nor? pole4 ,y c see1 !n1 t if a compass be tak5 nor? ( ?is magnetic pole1 its nor? pole w po9t s\?4 ,l9es ( =ce pass f ! e>?'s nor? magnetic pole ?r\gh ! air on all sides ( ! e>? & ent] ! e>?'s s\? magnetic pole4 ,! compass-ne$le1 9 po9t+ t[>d ! nor? magnetic pole1 m]ely takes ! direction ( ! e>?'s l9es ( =ce1 j z ! p>ticles ( iron fil+s arrange !mselves 9 ! magnetic figures4 #da4 ,decl9ation4 ,z ! magnetic ne$le does n po9t exactly to ! nor?1 an angle is =m$ betwe5 ! true nor? & s\? l9e & ! l9e ( ! ne$le4 ,9 ,fig4 #cb ! l9e m>k$ ,n ,s is ! true nor? & s\? l9e4 ,! angle ( v>iation1 or ! decl9ation1 is ! angle ,a betwe5 ! l9e ,n ,s & ! compass-ne$le4 ,illu/ration3 ,fig4 #cb4 ,illu/ration3 ,fig4 #cc4 #db4 ,dip or ,incl9ation4 ,if a piece ( /eel be c>efully balanc$ ^u a support1 & !n magnetiz$1 x w be f\nd t x w no long] balance4 ,! nor? pole w dip or po9t d[nw>d4 ,fig4 #cc %[s :at happ5s to a ne$le :5 x is held 9 diff]5t positions ov] a b> magnet4 ,x simply takes ! directions ( ! l9es ( =ce z !y pass f ! nor? to ! s\? pole ( ! magnet4 ,z ! e>?'s l9es ( =ce pass 9 curves f ! nor? to ! s\? magnetic pole1 y c see :y ! magnetic ne$le dips1 unless its s\? pole is made heavi] ?an its nor?4 ,magnetic ne$les are balanc$ aft] !y are magnetiz$4 ,illu/ration3 ,fig4 #cd4 ,fig4 #cd %[s a simple =m ( dipp+ ne$le4 ,^! are (t5 us$ by geologi/s & m9]s4 ,9 ! h&s ( ! prospector1 ! m9]'s compass1 or dipp+ ne$le1 proves a s]viceable guide to ! discov]y & location ( magnetic iron ore4 ,9 ?is in/rum5t ! magnetic ne$le is c>efully balanc$ ^u a horizontal axis )9 a graduat$ circle1 & 9 :i* ! ne$le w be f\nd to assume a position incl9$ to ! horizon4 ,?is angle ( deviation is call$ ! incl9ation or dip1 & v>ies 9 diff]5t latitudes1 & ev5 at diff]5t times 9 ! same place4 #dc4 ,! ,e>?'s ,inductive ,influ5ce4 ,! e>?'s magnetism acts inductively ^u pieces ( /eel or iron ^u its surface4 ,if a piece ( /eel or iron1 l a /ove pok]1 = example1 be held 9 a nor? & s\? l9e ) its nor? end dipp+ consid]ably1 x w be 9 ! be/ position = ! magnetism ( ! e>? to act ^u x2 t is1 x w lie 9 ! direction tak5 by ! e>?'s l9es ( =ce4 ,if ! pok] be /ruck two or ?ree times ) a hamm] to %ake up its molecules1 we %all f9d1 ^u te/+ x1 t x has become magnetiz$4 ,by ?is me?od we c p\nd magnetism "r out ( ! air ) a hamm]4 ,if ! magnetiz$ pok] be held level1 9 an ea/ & we/ direction1 x w no long] be act$ ^u to advantage by ! inductive influ5ce ( ! e>?1 & we c easily hamm] ! magnetism out ( x aga94 7,= exp]im5ts on magnets & magnetism see ,/udy1 ,"p ,i47 ,,*apt] ,,iii4 ,,h[ ,,electricity ,,is ,,g5]at$ ,,by ,,! ,,voltaic ,,cell4 #dd4 ,e>ly ,exp]im5ts4 ,9 #aghf ,galvani1 an ,italian physician1 made exp]im5ts to /udy ! effect ( /atic electricity ^u ! n]v\s excitability ( animals1 & especially ^u ! frog4 ,he f\nd t electric ma*9es 7 n necess>y to produce muscul> contractions or kicks ( ! frog's legs1 & t !y c\ld be produc$ :5 two diff]5t metals1 ,fig4 #ce1 l iron & copp]1 = example1 7 plac$ 9 prop] contact ) a n]ve & a muscle & !n made to t\* ea* o!r4 ,galvani fir/ ?\ght t ! frog g5]at$ ! electricity in/ead ( ! metals4 ,illu/ration3 ,fig4 #ce4 ,volta prov$ t ! electricity 0 caus$ by ! contact ( ! metals4 ,he us$ ! cond5s+ electroscope z "o means ( prov+ t two dissimil> metals become *>g$ diff]5tly :5 9 contact4 ,volta also c>ri$ out 8 belief by con/ruct+ :at is call$ a ,voltaic ,pile4 ,he ?\ght t by mak+ sev]al pairs ( metals s arrang$ t all ! little curr5ts w\ld help ea* o!r1 a /rong curr5t c\ld be g5]at$4 ,fig4 #cf %[s a pile1 x be+ made by plac+ a pair ( z9c & copp] discs 9 contact ) "o ano!r1 !n lay+ on ! copp] disc a piece ( flannel soak$ 9 br9e1 !n on top ( ?is ano!r pair1 etc41 etc4 ,by connect+ ! fir/ z9c & ! la/ copp]1 q a little curr5t 0 produc$4 ,?is 0 a />t f :i* has be5 built our pres5t k ( electricity4 ,/rictly speak+1 electricity is n g5]at$ by comb9ations ( metals or by cells2 !y really keep up a diff]5ce ( pot5tial1 z w be se54 ,illu/ration3 ,fig4 #cf4 ,illu/ration3 ,fig4 #cg4 ,illu/ration3 ,fig4 #ch4 #de4 ,! ,simple ,cell4 ,x has be5 /at$ t two diff]5t k9ds ( electrifications may be produc$ by friction2 "o positive1 ! o!r negative4 ,ei!r c be produc$1 at w1 by us+ prop] mat]ials4 ,fig4 #cg %[s a section ( a simple cell2 ,fig4 #ch %[s ano!r view4 ,cu is a piece ( copp]1 & ,zn a piece ( z9c4 ,:5 !y are plac$ 9 dilute sulphuric acid1 x c be %[n by delicate app>atus t !y become *>g$ diff]5tly1 because ! acid acts diff]5tly ^u ! plates4 ,!y become *>g$ by *emical action1 & n by friction4 ,! z9c is gradually dissolv$1 & x is ?is *emical burn+ ( ! z9c t furni%es en]gy = ! electric curr5t 9 ! simple cell4 ,! electrification1 or *>ge1 on ! plates t5ds to fl[ f ! place ( high] to ! place ( l[] pot5tial1 j z wat] t5ds to fl[ d[n hill4 ,if a wire be jo9$ to ! two metals1 a con/ant curr5t ( electricity w fl[ ?r\gh x1 because ! acid cont9ues to act ^u ! plates4 ,! simple cell is a s+le-fluid cell1 z b "o liquid is us$ 9 its con/ruction4 #de;a4 ,plates & ,poles4 ,! metal /rips us$ 9 voltaic cells are call$ plates or elem5ts4 ,! "o mo/ act$ ^u by ! acid is call$ ! positive 77 plate4 ,9 ! simple cell ! z9c is ! plate1 & ! copp] ! negative 7-7 plate4 ,! end ( a wire atta*$ to ! - plate is call$ ! pole1 or electrode4 ,fig4 #cg %[s ! negative 7-7 electrode z ! end ( ! wire atta*$ to ! plate4 #df4 ,direction ( ,curr5t4 ,9 ! cell ! curr5t passes f ! z9c to ! copp]2 t is1 f ! positive to ! negative plate1 :]e bubbles ( hydrog5 gas are deposit$4 ,9 ! wire connect+ ! plates1 ! curr5t passes f ! copp] to ! z9c plate4 ,9 mo/ cells1 c>bon takes ! place ( copp]4 7,see ,/udy1 #bfh47 #dg4 ,local ,curr5ts2 ,amalgamation4 ,ord9>y z9c conta9s impurities su* z c>bon1 iron1 etc41 & :5 ! acid comes 9 contact ) ^!1 !y =m ) ! z9c a small cell4 ,?is t5ds to eat away ! z9c )\t produc+ useful curr5ts4 ,! little curr5ts 9 ! cell f ?is cause are call$ local curr5ts4 7,see ,/udy1 ,exp4 #aaa1 #bgc47 ,?is is l>gely ov]come by coat+ ! z9c ) m]cury4 ,?is process is call$ amalgamation4 ,x makes ! z9c act l pure z9c1 :i* is n act$ ^u by dilute sulphuric acid :5 ! curr5t does n pass4 7,see ,/udy1 #beg1 #bgd47 #dh4 ,pol>ization ( ,cells4 ,bubbles ( hydrog5 gas are =m$ :5 z9c is dissolv$ by an acid4 ,9 ! ord9>y simple cell ^! bubbles collect on ! copp] plate1 & n on ! z9c plate1 z might be expect$4 ,! hydrog5 is n a conductor ( electricity1 s ?is film ( gas holds ! curr5t back4 ,! hydrog5 acts l a metal & sets up a curr5t t opposes ! z9c to ! copp] curr5t4 ,sev]al me?ods are employ$ to get rid ( ! hydrog54 7,see ,/udy1 #bgh1 #bgi1 #bhj47 ,,*apt] ,,iv4 ,,v>i\s ,,voltaic ,,cells4 #di4 ,s+le-,fluid & ,two-,fluid ,cells4 ,! simple cell 7 #de7 is a s+le-fluid cell4 ,! liquid is call$ ! electrolyte1 & ?is mu/ act ^u "o ( ! plates2 t is1 *emical action mu/ take place 9 ord] to produce a curr5t4 ,! simple cell pol>izes rapidly1 s some?+ mu/ be us$ ) ! dilute sulphuric acid to de/roy ! hydrog5 bubbles4 ,?is is done 9 ! bi*romate ( pota% cell4 ,9 ord] to get complete depol>ization--t is1 to keep ! c>bon plate almo/ p]fectly free f hydrog51 x is necess>y to use two-fluid cells1 or ^? to :i* "s solid depol>iz] is add$ to ! "o fluid4 #ej4 ,op5 & ,clos$ ,circuit ,cells4 ,if we consid] a voltaic cell1 ! wires atta*$ to x1 & p]haps "s in/rum5t ?r\gh :i* ! curr5t passes1 we h an electric circuit4 ,:5 ! curr5t passes1 ! circuit is clos$1 b :5 ! wire is cut1 or 9 any way disconnect$ s t ! curr5t c n pass1 ! circuit is op5 or brok54 7,see ,/udy1 #bff47 ,op5 ,circuit ,cells are ^? :i* c give mom5t>y curr5ts at int]vals1 su* z are ne$$ = bells1 telephones1 etc4 ,^! mu/ h pl5ty ( "t to re/1 z !y pol>ize :5 ! circuit is clos$ = a long "t4 ,! ,leclan* & dry cells are ! mo/ common op5 circuit cells4 ,clos$ ,circuit ,cells4 ,= telegraph l9es1 motors1 etc41 :]e a curr5t is ne$$ = "s "t1 ! cell mu/ be ( su* a nature t x w n pol>ize quickly2 x mu/ give a /rong & con/ant curr5t4 ,! bi*romate & gravity cells are examples ( ?is v>iety4 7,see ,/udy1 #bhf47 #ea4 ,bi*romate ( ,pota% ,cells are v useful = g5]al laboratory "w4 ,!y are especially useful = op]at+ induction coils1 small motors1 small inc&esc5t lamps1 = heat+ plat9um wires1 etc4 ,^! cells h an ,e4,m4,f4 ( ab\t #b volts4 ,dilute sulphuric acid is us$ z ! excit+ fluid1 & 9 ?is is dissolv$ ! bi*romate ( pota% :i* keeps ! hydrog5 bubbles f ! c>bon plate4 7,see ,app>atus ,book1 #bf47 ,z9c & c>bon are us$ = ! plates1 ! pole be+ ! wire atta*$ to ! c>bon4 ,illu/ration3 ,fig4 #ci4 ,fig4 #ci %[s "o =m ( bi*romate cell4 ,x furni%es a l>ge quantity ( curr5t1 & z ! z9c c be rais$ f ! fluid1 x may be kept *>g$ ready = use = _m mon?s1 & c be set 9 action any "t :5 requir$ by l[]+ ! z9c into ! liquid4 ,two ( ^! cells w burn a "o c&le-p[] m9iature inc&esc5t lamp sev]al h\rs4 ,! c>bon is inde/ructible4 ,note4 ,= v>i\s =ms ( home-made cells1 see ,app>atus ,book1 ,*apt] ,i41 & = batt]y fluids see ,*apt] ,,ii4 #eb4 ,! ,gr5et ,cell4 ,fig4 #dj is ano!r =m ( bi*romate cell4 ,! c>bon plates are left 9 ! fluid con/antly4 ,! z9c plate %\ld be rais$ :5 ! cell is n 9 use1 to keep x f be+ uselessly dissolv$4 ,illu/ration3 ,fig4 #dj4 ,illu/ration3 ,fig4 #da4 #ec4 ,plunge ,batt]ies4 ,two or m cells are (t5 arrang$ s t _! elem5ts c be quickly l[]$ into ! acid solution4 ,su* a comb9ation1 ,fig4 #da1 is call$ a plunge batt]y4 ,! b9d+-po/s are s arrang$ t curr5ts ( diff]5t /r5g?s c be tak5 f ! comb9ation4 ,! two b9d+-po/s on ! "r ( ! batt]y w give ! curr5t ( "o cell2 ! two b9d+-po/s on ! left ( ! batt]y w give ! curr5t ( two cells1 & ! two end b9d+-po/s w give ! curr5t ( all ?ree cells4 ,:5 n 9 use ! elem5ts mu/ always be hung on ! hooks & kept out ( ! solution4 #ed4 ,l>ge ,plunge ,batt]ies4 ,fig4 #db1 are arrang$ ) a w9* & a b> above ! cells2 ^! af=d a ready & conv5i5t means ( lift+ or l[]+ ! elem5ts & avoid+ wa/e4 ,9 ! batt]y %[n1 ,fig4 #db1 ! z9cs are #df in*es2 ! c>bons h ! same dim5sions1 b !re are two c>bon plates to ea* z9c1 ?us giv+ d\ble ! c>bon surface4 ,illu/ration3 ,fig4 #db4 #ee4 ,! ,full] ,cell1 ,fig4 #dc1 is ano!r type ( bi*romate cell1 us$ l>gely = long-di/ance telephone s]vice1 = telephone ex*ange & swit* s]vice1 = runn+ small motors1 etc4 ,x consi/s ( a glass j>1 a c>bon plate1 ) prop] connections1 a clay por\s cup1 conta9+ ! z9c1 :i* is made 9 ! =m ( a cone4 ,a little m]cury is plac$ 9 ! por\s cup to keep ! z9c well amalgamat$4 ,ei!r bi*romate ( pota% or bi*romate ( soda c be us$ z a depol>iz]4 ,illu/ration3 ,fig4 #dc4 ,illu/ration3 ,fig4 #dd4 #ef4 ,! ,gravity ,cell1 sometimes call$ ! blue/one or cr[foot cell1 is us$ l>gely = telegraph1 police1 & fire-al>m signal s]vice1 laboratory & exp]im5tal "w1 or :5ev] a clos$ circuit cell is requir$4 ,! ,e4,m4,f4 is ab\t "o volt4 ,?is is a modifi$ =m ( ! ,daniell cell4 ,fig4 #dd %[s a home-made gravity cell4 ,a copp] plate is plac$ at ! bottom ( ! glass j>1 & ^u ?is re/s a solution ( copp] sulphate 7blue/one74 ,! z9c plate is support$ ab\t f\r in*es above ! copp]1 & is surr\nd$ by a solution ( z9c sulphate :i* floats ^u ! top ( ! blue solution4 ,an insulat$ wire rea*es f ! copp] to ! top ( ! cell & =ms ! positive pole4 7,see ,app>atus ,book1 #aa to #ae1 = home-made gravity cell1 its regulation1 etc4 ,= exp]im5ts ) two-fluid ,daniell cell1 see ,/udy1 ,exp4 #aac1 #bha to #bhf47 ,illu/ration3 ,fig4 #de4 #ef;a4 ,buns5 ,cells1 ,fig4 #de1 are us$ = motors1 small inc&esc5t lamps1 etc4 ,a c>bon rod is inclos$ 9 a por\s cup1 on ! outside ( :i* is a cyl9d] ( z9c t /&s 9 dilute sulphuric acid1 ! c>bon be+ 9 nitric acid4 #eg4 ,! ,leclan* ,cell is an op5 circuit cell4 ,sal ammoniac is us$ z ! excit+ fluid1 c>bon & z9c be+ us$ = plates4 ,manganese dioxide is us$ z ! depol>iz]2 ?is surr\nds ! c>bon plate1 ! two be+ ei!r pack$ toge!r 9 a por\s cup or held toge!r 9 ! =m ( cakes4 ,! por\s cup1 or press$ cake1 /&s 9 ! excit+ fluid4 ,! ,e4 ,m4 ,f4 is ab\t #a4e volts4 ,illu/ration3 ,fig4 #df4 ,illu/ration3 ,fig4 #dg4 ,illu/ration3 ,fig4 #dh4 ,illu/ration3 ,fig4 #di4 ,fig4 #df %[s a =m ) por\s cup4 ,! b9d+-po/ at ! top ( ! c>bon plate =ms ! electrode1 ! curr5t leav+ ! cell at ?is po9t4 ,! ,gonda ,prism ,cell 7,fig4 #dg71 is a =m ( ,leclan* 9 :i* ! depol>iz] is 9 ! =m ( a cake4 #eh4 ,dry ,cells are op5 circuit cells1 & c be c>ri$ ab\t1 al?\gh !y are moi/ inside4 ,! pole is ! end ( ! c>bon plate4 ,z9c is us$ z ! outside case & plate4 ,fig4 #dh %[s ! ord9>y =ms4 ,fig4 #di %[s a numb] ( dry cells arrang$ 9 a box ) swit* 9 front1 s t ! curr5t c be regulat$ at w4 ,illu/ration3 ,fig4 #ej4 #ei4 ,! ,edison-,lel&e ,cells1 ,fig4 #ej1 are made 9 sev]al sizes & types4 ,z9c & copp] oxide1 :i* is press$ into plates1 =m ! elem5ts4 ,! excit+ fluid consi/s ( a #be p] c5t4 solution ( cau/ic pota% 9 wat]4 ,!y are design$ = bo? op5 & clos$ circuit "w4 ,,*apt] ,v4 ,,ab\t ,,pu%-,,buttons1 ,,swit*es ,,& ,,b9d+-,,po/s4 #fj4 ,electrical ,connections4 ,9 exp]im5tal "w1 z well z 9 ! ev]yday "w ( ! electrician1 electrical connections mu/ con/antly be made4 ,"o wire mu/ be jo9$ to ano!r1 j = a mom5t1 p]haps1 or "o piece ( app>atus mu/ be put 9 an electric circuit ) o!r app>atus1 or ! curr5t mu/ be turn$ on or (f f motors1 lamps1 etc4 ,9 ord] to conv5i5tly & quickly make su* connections1 app>atus call$ pu%-buttons1 swit*es & b9d+-po/s are us$4 ,illu/ration3 ,fig4 #ea4 ,illu/ration3 ,fig4 #eb4 #fa4 ,pu%-,buttons4 ,! simple act ( press+ y\r f+] ^u a movable button1 or knob1 may r+ a bell a mile away1 or d "s o!r equally wond]ful ?+4 ,fig4 #ea %[s a simple pu%-button1 some:at l a simple key 9 con/ruction4 ,if we cut a wire1 ?r\gh :i* a curr5t is pass+1 !n jo9 "o ( ! free ends to ! screw ,a & ! o!r end to screw ,c1 we %all be able to let ! curr5t pass at any in/ant by press+ ! spr+ ,b firmly ^u ,a4 ,pu%-buttons are made 9 all sorts ( %apes & sizes4 ,fig4 #eb gives an idea ( ! g5]al int]nal con/ruction4 ,! curr5t ent]s ,a by "o wire1 & leaves by ano!r wire z soon z ! button is pu%$ & ,b is =c$ d[n to ,a4 ,! bottom ( ! little button re/s ^u ! top ( ,b4 ,fig4 #ec %[s a ,table ,clamp-,pu% = use on d9+-tables1 c>d-tables1 *airs1 desks1 & o!r movable furniture4 ,fig4 #ed %[s a comb9ation ( pu%-button1 speak+-tube1 & lett]-box us$ 9 city ap>tm5t h\ses4 ,fig4 #ee %[s an ,indicat+ ,pu%4 ,! buzz] indicates1 by ! s\nd1 :e!r ! call has be5 he>d2 t is1 ! p]son call$ answ]s back4 ,illu/ration3 ,fig4 #ec4 ,illu/ration3 ,fig4 #ed4 ,modifications ( ord9>y pu%-buttons are us$ = floor pu%-buttons1 on doors1 w9d[s1 etc41 = burgl>-al>ms1 = turn+ (f or on lights1 etc41 etc4 7,see ,app>atus ,book1 ,*apt] ,,iii41 = home-made pu%-buttons47 ,illu/ration3 ,fig4 #ee4 #fb4 ,swit*es h a movable b> or plug ( metal1 mov+ on a pivot1 to make or break a circuit1 or transf] a curr5t f "o conductor to ano!r4 ,fig4 #ef %[s a s+le po9t swit*4 ,! curr5t ent]+ ! pivot$ arm c g no f>!r :5 ! swit* is op51 z %[n4 ,to close ! circuit1 ! arm is pu%$ ov] until x presses d[n ^u ! contact-po9t4 ,= neatness1 bo? wires are jo9$ to ! "u side ( ! swit* or to b9d+-po/s4 ,illu/ration3 ,fig4 #ef4 ,fig4 #eg %[s a knife swit*4 ,copp] blades are press$ d[n betwe5 copp] spr+ clips to close ! circuit4 ,! h&le is made ( insulat+ mat]ial4 ,pole-*ang+ swit*es1 ,fig4 #eh1 are us$ = *ang+ or rev]s+ ! poles ( batt]ies1 etc4 ,fig4 #ei %[s a home-made swit*1 useful 9 connection ) resi/ance coils4 ,by jo9+ ! ends ( ! coils ,a1 ,b1 ,c1 ,d1 ) ! contact-po9ts #a1 #b1 #c1 etc41 m or less resi/ance c be easily ?r[n 9 by simply sw++ ! lev] ,e ar\nd to ! left or "r4 ,if ,e be turn$ to #a1 ! curr5t w be oblig$ to pass ?r\gh all ! coils ,a1 ,b1 etc41 be=e x c pass out at ,y4 ,if ,e be mov$ to #c1 coils ,a & ,b w be cut out ( ! circuit1 ?us decreas+ ! resi/ance to ! curr5t on its way f ,x to ,y4 ,curr5t regulators are made ^u ?is pr9ciple4 7,see ,app>atus ,book1 ,*apt] ,,iv41 = home-made swit*es47 ,illu/ration3 ,fig4 #eg4 ,illu/ration3 ,fig4 #eh4 ,illu/ration3 ,fig4 #ei4 ,swit*bo>ds are made conta9+ f two or ?ree to hundr$s ( swit*es1 & are us$ 9 telegraph & telephone "w1 9 electric light /ations1 etc41 etc4 7,see ,*apt] on ,c5tral ,/ations47 ,fig4 #fj %[s a swit* us$ = inc&esc5t light+ curr5ts4 ,illu/ration3 ,fig4 #fj4 ,illu/ration3 ,fig4 #fa4 #fc4 ,b9d+-,po/s are us$ to make connections betwe5 two pieces ( app>atus1 betwe5 two or m wires1 betwe5 a wire & any app>atus1 etc41 etc4 ,!y all[ ! wires to be quickly fa/5$ or unfa/5$ to ! app>atus4 ,a l>ge "p ( ! app>atus %[n 9 ?is book has b9d+-po/s atta*$4 ,fig4 #fa %[s a few ( ! common =ms us$4 7,see ,app>atus ,book1 ,*apt] ,v41 = home-made b9d+-po/s47 ,,*apt] ,,vi4 ,,units ,,& ,,app>atus ,,= ,,electrical ,,measurem5ts4 #fd4 ,electrical ,units4 ,9 ord] to measure electricity = exp]im5tal or comm]cial purposes1 /&>ds or units are j z necess>y z ! in* or foot = measur+ di/ances4 #fe4 ,pot5tial2 ,electromotive ,=ce4 ,if wat] 9 a tall tank be all[$ to squirt f two holes1 "o ne> ! bottom1 ! o!r ne> ! top1 x is evid5t t ! =ce ( ! wat] t comes f ! hole at ! bottom w be ! great]4 ,! pressure at ! bottom is great] ?an t ne> ! top1 because ! head is great]4 ,:5 a sp>k ( /atic electricity jumps a long di/ance1 we say t ! *>ge has a high pot5tial2 t is1 x has a high electrical pressure4 ,pot5tial1 = electricity1 means ! same z pressure1 = wat]4 ,! great] ! pot5tial1 or electromotive =ce 7,e4,m4,f47 ( a cell1 ! great] its p[] to pu% a curr5t ?r\gh wires4 7,see ,/udy1 #bif to #cje1 ) exp]im5ts47 #ff4 ,unit ( ,e4,m4,f42 ! ,volt4--,9 speak+ ( wat]1 we say t its pressure is s _m p\nds to ! squ>e in*1 or t x has a fall1 or head1 ( s _m feet4 ,we speak ( a curr5t z hav+ s _m volts2 = example1 we say t a wire is c>ry+ a #aaj-volt curr5t4 ,! volt is ! unit ( ,e4,m4,f4 ,an ord9>y gravity cell has an ,e4,m4,f4 ( ab\t "o volt4 ,?is "n 0 giv5 9 honor ( ,volta4 #fg4 ,measurem5t ( ,electromotive ,=ce4 ,!re are sev]al ways by :i* ! ,e4,m4,f4 ( a cell1 = example1 c be measur$4 ,x is usually measur$ relatively1 by comp>ison ) ! ,e4 ,m4 ,f4 ( "s /&>d cell4 7,see ,/udy1 ,exp4 #adj1 = measur+ ! ,e4 ,m4 ,f4 ( a cell by comp>ison ) ! two-fluid cell47 ,illu/ration3 ,fig4 #fb4 ,voltmet]s are in/rum5ts by means ( :i* ,e4 ,m4 ,f4 c be read on a pr9t$ scale4 ,!y are a v>iety ( galvanomet]1 & are made ) coils ( su* high resi/ance1 comp>$ ) ! resi/ance ( a cell or dynamo1 t ! ,e4 ,m4 ,f4 c be read direct4 ,! reason = ?is w be se5 by ref]r+ to ,ohm's law 7,/udy1 #cef72 ! resi/ance is s great t ! /r5g? ( ! curr5t dep5ds entirely ^u ! ,e4 ,m4 ,f4 ,illu/ration3 ,fig4 #fc4 ,voltmet]s measure electrical pressure j z /eam gauges measure ! pressure ( /eam4 ,fig4 #fb %[s "o =m ( voltmet]4 ,fig4 #fc %[s a voltmet] ) illum9at$ dial4 ,an electrical bulb beh9d ! in/rum5t furni%es light s t ! read+s c be easily tak54 #fh4 ,electrical ,resi/ance4 ,did y ev] ride d[n hill on a h&-sl$8 ,h[ easily ! sl$ glides ov] ! sn[6 ,:at happ5s1 ?\gh1 :5 y /rike a b>e place1 or a place :]e "s evil-m9d$ p]son has spr9kl$ a%es8 ,does ! sl$ pass easily ov] b>e gr\nd or a%es8 ,sn[ (f]s v little resi/ance to ! sl$1 :ile a%es (f] a great resi/ance4 ,illu/ration3 ,fig4 #fd4 ,all sub/ances d n all[ ! electric curr5t to pass ?r\gh !m ) ! same ease4 ,ev5 ! liquid 9 a cell t5ds to hold ! curr5t back & (f]s int]nal resi/ance4 ,! v>i\s wires & in/rum5ts connect$ to a cell (f] ext]nal resi/ance4 7,see ,/udy1 ,*apt] ,,xviii41 = exp]im5ts1 etc47 #fi4 ,unit ( ,resi/ance4 ,! ,ohm is ! "n giv5 to ! unit ( resi/ance4 ,ab\t #i ft4 #i 94 ( ,no4 #cj copp] wire1 or #ci feet #a 94 ( ,no4 #bd copp] wire1 w make a fairly accurate ohm4 ,resi/ance coils1 hav+ c>efully measur$ resi/ances1 are made = /&>ds4 7,see ,app>atus ,book1 ,*apt] ,,xvii41 = home-made resi/ance coils47 ,fig4 #fd %[s a comm]cial =m ( a /&>d resi/ance coil4 ,! coil is inclos$ 9 a case & has l>ge wires lead+ f its ends = connections4 ,fig4 #fe gives an idea ( ! way 9 :i* coils are w\nd & us$ ) plugs to build up resi/ance boxes1 ,fig4 #ff4 #gj4 ,laws ( ,resi/ance4 #a4 ,! resi/ance ( a wire is directly proportional to its l5g?1 provid$ its cross-section1 mat]ial1 etc41 are uni=m4 #b4 ,! resi/ance ( a wire is inv]sely proportional to its area ( cross-section2 or1 9 o!r words1 inv]sely proportional to ! squ>e ( its diamet]1 o!r ?+s be+ equal4 ,illu/ration3 ,fig4 #fe4 #c4 ,! resi/ance ( a wire dep5ds ^u its mat]ial1 z well z ^u its l5g?1 size1 etc4 #d4 ,! resi/ance ( a wire increases z its temp]ature rises4 7,see ,/udy1 ,*apt]s ,,xviii4 & ,,xix41 = exp]im5ts on resi/ance1 its measurem5t1 etc47 ,illu/ration3 ,fig4 #ff4 #ga4 ,curr5t ,/r5g?4 ,! /r5g? ( a curr5t at ! end ( a circuit dep5ds n only ^u ! electrical pressure1 or ,e4 ,m4 ,f41 :i* drives ! curr5t1 b also ^u ! resi/ance :i* has to be ov]come4 ,! great] ! resi/ance ! weak] ! curr5t at ! end ( its j\rney4 #gb4 ,unit ( ,curr5t ,/r5g?2 ,! ,amp]e4 ,a curr5t hav+ an ,e4 ,m4 ,f4 ( "o volt1 pu%+ its way ?r\gh a resi/ance ( "o ohm1 w\ld h a unit ( /r5g?1 call$ "o amp]e4 ,?is curr5t1 "o amp]e /rong1 w\ld deposit1 "u prop] conditions1 4#jjjcbgg gramme ( copp] 9 "o second f a solution ( copp] sulphate4 #gc4 ,measurem5t ( ,curr5t ,/r5g?4 ,a magnetic ne$le is deflect$ :5 a curr5t passes ar\nd x1 z 9 in/rum5ts l ! galvanomet]4 ,! galvanoscope m]ely indicates ! pres5ce ( a curr5t4 ,galvanomet]s measure ! /r5g? ( a curr5t1 & !y are made 9 _m =ms1 dep5d+ ^u ! nature & /r5g? ( ! curr5ts to be measur$4 ,galvanomet]s are /&>diz$1 or calibrat$1 by special measurem5ts1 or by comp>ison ) "s /&>d in/rum5t1 s t :5 ! deflection is a c]ta9 numb] ( degrees1 ! curr5t pass+ ?r\gh x is kn[n to be ( a c]ta9 /r5g?4 ,illu/ration3 ,fig4 #fg4 ,fig4 #fg %[s an a/atic galvanomet]4 ,fig4 #fh %[s a tang5t galvanomet]1 9 :i* ! /r5g? ( ! curr5t is proportional to ! tang5t ( ! angle ( deflection4 ,fig4 #fi %[s a ,d',arsonval galvanomet]1 9 :i* a coil ( wire is susp5d$ betwe5 ! poles ( a p]man5t horse%oe magnet4 ,! l9es ( =ce are conc5trat$ by ! iron core ( ! coil4 ,! two ?9 susp5d+ wires convey ! curr5t to ! coil4 ,a ray ( light is reflect$ f ! small mirror & acts z a po9t] z 9 o!r =ms ( reflect+ galvanomet]s4 ,illu/ration3 ,fig4 #fh4 #gd4 ,! ,ammet]1 ,fig4 #gj1 is a =m ( galvanomet] 9 :i* ! /r5g? ( a curr5t1 9 amp]es1 c be read4 ,9 ^! ! /r5g? ( curr5t is proportional to ! angul> deflections4 ,! coils are made ) a small resi/ance1 s t ! curr5t w n be greatly r$uc$ 9 /r5g? 9 pass+ ?r\gh !m4 ,illu/ration3 ,fig4 #fi4 #ge4 ,voltamet]s measure ! /r5g? ( a curr5t by *emical means1 ! quantity ( metal deposit$ or gas g5]at$ be+ proportional to ! "t t ! curr5t fl[s & to its /r5g?4 ,9 ! wat] voltamet]1 ,fig4 #ga1 ! hydrog5 & oxyg5 produc$ 9 a giv5 "t are measur$4 7,see ,/udy1 ,*apt] ,,xxi47 ,illu/ration3 ,fig4 #gj4 ,! copp] voltamet] measures ! am\nt ( copp] deposit$ 9 a giv5 "t by ! curr5t4 ,fig4 #gb %[s "o =m4 ,! copp] ca?ode is weigh$ be=e & aft] ! curr5t fl[s4 ,! weight ( copp] deposit$ & ! "t tak5 are us$ to calculate ! curr5t /r5g?4 ,illu/ration3 ,fig4 #ga4 #gf4 ,unit ( ,quantity2 ,! ,c\lomb is ! quantity ( electricity giv51 9 "o second1 by a curr5t hav+ a /r5g? ( "o amp]e4 ,"t is an important elem5t 9 consid]+ ! "w a curr5t c d4 ,illu/ration3 ,fig4 #gb4 #gg4 ,electrical ,horse-p[]2 ,! ,watt is ! unit ( electrical p[]4 ,a curr5t hav+ ! /r5g? ( "o amp]e1 & an ,e4 ,m4 ,f4 ( "o volt has a unit ( p[]4 #gdf watts make "o electrical horse-p[]4 ,watts amp]es volts4 ,fig4 #gc %[s a direct read+ wattmet] bas$ on ! int]national volt & amp]e4 ,!y save tak+ simultane\s ammet] & voltmet] read+s1 :i* are o!rwise necess>y to get ! product ( volts & amp]es1 & are also us$ on alt]nat+ curr5t measurem5ts4 ,illu/ration3 ,fig4 #gc4 ,!re are also =ms ( wattmet]s1 ,fig4 #gd1 9 :i* ! watts are read f dials l ^? on an ord9>y gas-met]1 ! records be+ p]man5t4 ,fig4 #ge %[s a voltmet] ,v1 & ammet] ,a1 s plac$ 9 ! circuit t read+s c be tak54 ,d repres5ts a dynamo4 ,a is plac$ s t ! :ole curr5t passes ?r\gh x1 :ile ,v is plac$ betwe5 ! ma9 wires to measure ! diff]5ce 9 pot5tial4 ,! product ( ! two read+s 9 volts & amp]es gives ! numb] ( watts4 ,illu/ration3 ,fig4 #gd4 #gh4 ,*emical ,met]s also measure ! quantity ( curr5t t is us$2 = example1 "o may be plac$ 9 ! cell> to measure ! quantity ( curr5t us$ to light ! h\se4 ,illu/ration3 ,fig4 #ge4 ,fig4 #gf %[s a *emical met]1 a "p ( ! curr5t pass+ ?r\gh a j> conta9+ z9c plates & a solution ( z9c sulphate4 ,metallic z9c is dissolv$ f "o plate & deposit$ ^u ! o!r4 ,! increase 9 weight %[s ! am\nt ( *emical action :i* is proportional to ! amp]e h\rs4 ,kn[+ ! relation betwe5 ! quantity ( curr5t t c pass ?r\gh ! solution to t :i* c pass ?r\gh ! met] by ano!r conductor1 a calculation c be made :i* w give ! curr5t us$4 ,a lamp is s arrang$ t x automatically lights be=e ! met] gets to ! freez+-po9t2 ?is w>ms x up to ! prop] temp]ature1 at :i* po9t ! light goes out aga94 ,illu/ration3 ,fig4 #gf4 ,,*apt] ,,vii4 ,,*emical ,,effects ,,( ,,! ,,electric ,,curr5t4 #gi4 ,electrolysis4 ,x has be5 se5 t 9 ! voltaic cell electricity is g5]at$ by *emical action4 ,sulphuric acid acts ^u z9c & dissolves x 9 ! cell1 hydrog5 is produc$1 etc4 ,:5 ?is process is rev]s$1 t is1 :5 ! electric curr5t is pass$ ?r\gh "s solutions1 !y are decompos$1 or brok5 up into _! con/itu5ts4 ,?is process is call$ electrolysis1 & ! comp\nd decompos$ is ! electrolyte4 7,see ,/udy1 #cfi1 etc41 ) exp]im5ts47 ,illu/ration3 ,fig4 #gg4 ,fig4 #gg %[s h[ wat] c be decompos$ into its two con/itu5ts1 hydrog5 & oxyg51 !re be+ twice z mu* hydrog5 =m$ z oxyg54 ,fig4 #gh %[s a glass j> 9 :i* are plac$ two metal /rips1 ,a & ,c1 ^! be+ connect$ ) two cells4 ,9 ?is j> may be plac$ v>i\s conduct+ solutions to be te/$4 ,if1 = example1 we use a solution ( copp] sulphate1 its *emical =mula be+ ,cu,s,o#d1 ! curr5t w break x up into ,cu 7copp]7 & ,,s#d4 ,! ,cu w be deposit$ ^u ,c z ! curr5t passes f ,a to ,c ?r\gh ! solution4 ,a is call$ ! anode1 & ,c ! ca?ode4 ,illu/ration3 ,fig4 #gh4 ,fig4 #gi %[s ano!r =m ( j> us$ to /udy ! decomposition ( solutions by ! electric curr5t4 ,illu/ration3 ,fig #gi4 #hj4 ,ions4 ,:5 a solution is decompos$ into p>ts by a curr5t1 ! p>ts are call$ ! ,ions4 ,:5 copp] sulphate 7,cu ,,s#d7 is us$1 ! ions are ,cu1 :i* is a metal1 & ,,s#d1 call$ an acid radical4 ,:5 silv] nitrate 7,ag ,,no#c7 is us$1 ,ag & ,,no#c are ! ions4 ,! metal "p ( ! comp\nd goes to ! ca?ode4 ,,*apt] ,,viii4 ,,h[ ,,electroplat+ ,,& ,,electrotyp+ ,,are ,,done4 #ha4 ,electricity & ,*emical ,action4 ,we h j se51 ,*apt] ,,vii41 t ! electric curr5t has ! p[] to decompose c]ta9 comp\nds :5 !y are 9 solution4 ,by *oos+ ! "r solutions1 !n1 we %all be able to get copp]1 silv]1 & o!r metals set free by electrolysis4 #hb4 ,electroplat+ consi/s 9 coat+ sub/ances ) metal ) ! aid ( ! electric curr5t4 ,if we wi% to electroplate a piece ( metal ) copp]1 = example1 we c use ! arrangem5t %[n 9 ,fig4 #gh1 9 :i* ,c is ! ca?ode plate to be cov]$1 & ,a is a copp] plate4 ,! two are 9 a solution ( copp] sulphate1 &1 z expla9$ 9 #gi1 ! solution w be decompos$4 ,copp] w be deposit$ ^u ,c1 & ! ,,s#d "p ( ! solution w g to ! anode ,a1 :i* x w attack & gradually dissolve4 ,! ,,s#d1 act+ ^u ! copp] anode1 makes ,cu,s,o#d aga91 & ?is keeps ! solution at a uni=m /r5g?4 ,! am\nt ( copp] dissolv$ f ! copp] anode equals1 ne>ly1 ! am\nt deposit$ ^u ! ca?ode4 ,! metal is c>ri$ 9 ! direction ( ! curr5t4 ,if we wi% to plate some?+ ) silv] or gold1 x w be necess>y to use a solution ( silv] or gold = ! electrolyte1 a plate ( metallic silv] or gold be+ us$ = ! anode1 z ! case may be4 ,great c>e is us$ 9 clean+ sub/ances to be plat$1 all dirt & grease be+ c>efully remov$4 ,fig4 #hj %[s a plat+ ba? 9 :i* sev]al articles c be plat$ at ! same "t by hang+ !m ^u a metal b> :i* really =ms a "p ( ! ca?ode4 ,if1 = example1 we wi% to plate knives1 spoons1 etc41 ) silv]1 !y w\ld be hung f ! b> %[n1 ea* be+ a "p ( ! ca?ode4 ,! vat w\ld conta9 a solution ( silv]1 & f ! o!r b> w\ld be hung a silv] plate hav+ a surface ab\t equal to t ( ! comb9$ knives1 etc4 ,illu/ration3 ,fig4 #hj4 ,mo/ metals are coat$ ) copp] be=e !y are plat$ ) silv] or gold4 ,:5 plat+ is done on a l>ge scale1 a curr5t f a dynamo is us$4 ,= exp]im5tal purposes a ,gravity cell w d v well4 7,see ,/udy1 #cgd to #chj ) exp]im5ts47 #hc4 ,electrotyp+4 ,x 0 obs]v$ by ,de ,la ,rue 9 #ahcf t 9 ! ,daniell cell an ev5 coat+ ( copp] 0 deposit$ ^u ! copp] plate4 ,f ?is 0 develop$ ! process ( electrotyp+1 :i* consi/s 9 mak+ a copy 9 metal ( a wood-cut1 page ( type1 etc4 ,a m\ld or impression ( ! type or co9 is fir/ made 9 wax1 or o!r suitable mat]ial4 ,^! m\lds are1 ( c\rse1 ! rev]se ( ! orig9al1 & z !y d n conduct electricity1 h to be coat$ ) graphite4 ,?is ?9 coat+ l9es ! m\ld ) conduct+ mat]ial s t ! curr5t c get to e "p ( ! m\ld4 ,^! are !n hung ^u ! ca?ode 9 a ba? ( copp] sulphate z describ$ 9 #hb4 ,! electric curr5t :i* passes ?r\gh ! vat deposits a ?9 lay] ( metallic copp] next to ! graphite4 ,:5 ?is copp] gets ?ick en\gh1 ! wax is melt$ away f x1 leav+ a ?9 %ell ( copp]1 ! side next to ! graphite be+ exactly alike 9 %ape to ! type1 b made ( copp]4 ,^! ?9 copp] %eets are too ?9 to /& ! pressure necess>y on pr9t+ presses1 s !y are /r5g!n$ by back+ !m ) s(t metal :i* fills e crevice1 mak+ solid plates ab\t 94 ?ick4 ,^! plates or electrotypes are us$ to pr9t f1 ! orig9al type be+ us$ to set up ano!r page4 ,,*apt] ,,ix4 ,,! ,,/orage ,,batt]y1 ,,& ,,h[ ,,x ,,works4 #hd4 ,pol>ization4 ,x has be5 /at$ t a simple cell pol>izes rapidly on acc\nt ( hydrog5 bubbles t =m ^u ! copp] plate4 ,!y t5d to s5d a curr5t 9 ! opposite direction to t ( ! ma9 curr5t1 :i* is !reby weak5$4 ,illu/ration3 ,fig4 #ha4 #he4 ,electromotive ,=ce ( ,pol>ization4 ,x has be5 %[n1 ,fig4 #ga1 t wat] c be decompos$ by ! electric curr5t4 ,hydrog5 & oxyg5 h a /rong attraction or *emical aff9ity = ea* o!r1 or !y w\ld n unite to =m wat]4 ,?is attraction has to be ov]come be=e ! wat] c be decompos$4 ,z soon z ! decompos+ curr5t ceases to fl[1 ! gases =m$ try to ru% toge!r aga92 9 fact1 if ! wat] voltamet] be disconnect$ f ! cells & connect$ ) a galvanoscope1 ! pres5ce ( a curr5t w be %[n4 ,?is voltamet] w give a curr5t ) an ,e4 ,m4 ,f4 ( ne>ly #a4e volts2 s x is evid5t t we mu/ h a curr5t ) a high] voltage ?an ?is to decompose wat]4 ,?is ,e4 ,m4 ,f41 due to pol>ization1 is call$ ! ,e4 ,m4 ,f4 ( pol>ization4 #hf4 ,second>y or ,/orage ,batt]ies1 also call$ accumulators1 d n really /ore electricity4 ,!y mu/ be *>g$ by a curr5t be=e !y c give out any electricity4 ,*emical *anges are produc$ 9 ! /orage cells by ! *>g+ curr5t j z !y are 9 voltamet]s1 electroplat+ solutions1 etc42 s x is pot5tial *emical en]gy t is really /or$4 ,:5 ! new products are all[$ to g back to _! orig9al /ate1 by jo9+ ! electrodes ( ! *>g$ cell1 a curr5t is produc$4 ,fig4 #ha %[s two lead plates1 ,a & ,b1 imm]s$ 9 dilute sulphuric acid1 & connect$ ) two ord9>y cells4 ,a /rong curr5t w pass ?r\gh ! liquid betwe5 ,a & ,b at fir/1 b x w quickly become weak]1 z *emical *anges take place 9 ! liquid4 ,?is may be %[n by a galvanomet] put 9 ! circuit be=e beg9n+ ! exp]im5t4 ,by disconnect+ ! wires f ! cells & jo9+ !m to ! galvanomet]1 x w be %[n t a curr5t comes f ! lead plates4 ,?is arrangem5t may be call$ a simple /orage cell4 ,regul> /orage cells are *>g$ ) ! curr5t f a dynamo4 7,see ,/udy1 ,exp4 #aea47 ,illu/ration3 ,fig4 #hb4 ,! fir/ /orage cells 7 made ( pla9 lead plates1 roll$ up 9 su* a way t !y 7 close to ea* o!r1 b did n t\*4 ,^! 7 plac$ 9 dilute sulphuric acid4 ,!y 7 *>g$ 9 alt]nate directions sev]al times1 until ! lead became prop]ly act$ ^u1 at :i* "t ! cell w\ld furni% a curr5t4 ,a great improvem5t 0 made 9 #ahha1 by ,faure1 :o coat$ ! plates ) r$ lead4 ,illu/ration3 ,fig4 #hc4 ,! me?od n[ g5]ally practic$ is to ca/ a frame ( lead1 ) rais$ "r-angl$ ribs on ea* side1 ?us =m+ little depress$ squ>es1 or to pun* a lead plate full ( holes1 :i* squ>es or holes are !n fill$ ) a pa/y mixture ( r$ oxide ( lead 9 positive plates1 & ) li?>ge 9 negatives4 ,9 a =m call$ ! *loride batt]y1 in/ead ( cem5t+ lead oxide pa/e into or aga9/ a lead fram+ 9 ord] to obta9 ! necess>y active mat]ial1 ! latt] is obta9$ by a /rictly *emical process4 ,fig4 #hb %[s a /orage cell ) plates1 etc41 conta9$ 9 a glass j>4 ,fig4 #hc %[s a cell ( #da plates1 set up 9 a lead-l9$ wood tank4 ,fig4 #hd %[s ?ree cells jo9$ 9 s]ies4 ,_m /orage cells are us$ 9 c5tral electric light /ations to help ! dynamos dur+ ! ru% h\rs at night4 ,!y are *>g$ dur+ ! day :5 ! load on ! dynamos is n heavy4 ,fig4 #he %[s ano!r =m ( /orage cell conta9+ a numb] ( plates4 ,illu/ration3 ,fig4 #hd4 #hg4 ,! ,uses ( ,/orage ,batt]ies are almo/ numb]less4 ,! curr5t c be us$ = ne>ly ev]y?+ = :i* a con/ant curr5t is adapt$1 ! foll[+ be+ "s ( its applications3 ,c>riage propulsion2 electric laun* propulsion2 tra9 light+2 ya*t light+2 c>riage light+2 bicycle light+2 m9]s' lamps2 d5tal1 m$ical1 surgical1 & laboratory "w2 phonographs2 k9etoscopes2 automaton pianos2 sew+-ma*9e motors2 fan motors2 telegraph2 telephone2 electric bell2 electric fire-al>m2 heat regulat+2 railroad swit* & signal app>atus4 ,by ! in/all+ ( a /orage plant _m natural b small s\rces ( p[] may be utiliz$ 9 furni%+ light & p[]2 s\rces :i* o!rwise are n available1 because n l>ge en\gh to supply maximum dem&s4 ,! =ce ( ! tides1 ( small wat] p[]s f irrigat+ dit*es1 & ev5 ( ! w9d1 come "u ?is head+4 ,illu/ration3 ,fig4 #he4 ,z a regulator ( pressure1 9 case ( fluctuations 9 ! load1 ! value ( a /orage plant is ine/imable4 ,^! fluctuations ( load are p>ticul>ly noticeable 9 electric railway plants1 :]e ! dem& is con/antly ris+ & fall+1 sometimes jump+ f almo/ no?+ to ! maximum1 & vice v]sa1 9 a few seconds4 ,if = no o!r reason ?an ! prev5tion ( sev]e /ra9 on ! eng9es & g5]ators1 caus$ by ^! fluctuations ( dem&1 a /orage plant w be valuable4 ,,*apt] ,x4 ,,h[ ,,electricity ,,is ,,g5]at$ ,,by ,,heat4 #hh4 ,!rmoelectricity is ! "n giv5 to electricity t is g5]at$ by heat4 ,if a /rip ( iron1 ,i1 be connect$ betwe5 two /rips ( copp]1 ,c ,c1 ^! be+ jo9$ by a copp] wire1 ,c ,w1 we %all h an arrangem5t t w g5]ate a curr5t :5 heat$ at ei!r ( ! junctions betwe5 ,c & ,i4 ,:5 x is heat$ at ,a ! curr5t w fl[ z %[n by arr[s1 f ,c to ,i4 ,if we heat at ,b1 ! curr5t w fl[ 9 ! opposite direction ?r\gh ! metals1 al?\gh x w /ill g f ,c to ,i z be=e4 ,su* curr5ts are call$ !rmoelectric curr5ts4 ,illu/ration3 ,fig4 #hf4 ,diff]5t pairs ( metals produce diff]5t results4 ,antimony & bismu? are g5]ally us$1 because ! greate/ effect is produc$ by !m4 ,if ! end ( a /rip ( bismu? be sold]$ to ! end ( a simil> /rip ( antimony1 & ! free ends be connect$ to a galvanomet] ( l[ resi/ance1 ! pres5ce ( a curr5t w be %[n :5 ! po9t ( contact becomes hott] ?an ! re/ ( ! circuit4 ,! curr5t w fl[ f bismu? to antimony across ! jo9t4 ,by cool+ ! juncture bel[ ! temp]ature ( ! re/ ( ! circuit1 a curr5t w be produc$ 9 ! opposite direction to ! above4 ,! en]gy ( ! curr5t is kept up by ! heat absorb$1 j z x is kept up by *emical action 9 ! voltaic cell4 #hi4 ,pelti] ,effect4 ,if an electric curr5t be pass$ ?r\gh pairs ( metals1 ! p>ts at ! junction become slightly w>m] or cool] ?an be=e1 dep5d+ ^u ! direction ( ! curr5t4 ,?is action is really ! rev]se ( t 9 :i* curr5ts are produc$ by heat4 ,illu/ration3 ,fig4 #hg4 #ij4 ,!rmopiles4 ,z ! ,e4,m4,f4 ( ! curr5t produc$ by a s+le pair ( metals is v small1 sev]al pairs are usually jo9$ 9 s]ies1 s t ! diff]5t curr5ts w help ea* o!r by fl[+ 9 ! same direction4 ,su* comb9ations are call$ !rmoelectric piles1 or simply !rmopiles4 ,fig4 #hg %[s su* an arrangem5t1 9 :i* a l>ge numb] ( elem5ts are plac$ 9 a small space4 ,! junctures are s arrang$ t ! alt]nate ones come toge!r at "o side4 ,fig4 #hh %[s a !rmopile connect$ ) a galvanomet]4 ,! heat ( a mat*1 or ! cold ( a piece ( ice1 w produce a curr5t1 ev5 if held at "s di/ance f ! !rmopile4 ,! galvanomet] %\ld be a %ort-coil a/atic "o4 7,see ,/udy1 ,*apt] ,,xxiv41 = exp]im5ts & home-made !rmopile47 ,illu/ration3 ,fig4 #hh4 ,,*apt] ,,xi4 ,,magnetic ,,effects ,,( ,,! ,,electric ,,curr5t4 #ia4 ,electromagnetism is ! "n giv5 to magnetism t is develop$ by electricity4 ,we h se5 t if a magnetic ne$le be plac$ 9 ! field ( a magnet1 its ,n pole w po9t 9 ! direction tak5 by ! l9es ( =ce z !y pass f ! ,n to ! ,s pole ( ! magnet4 ,illu/ration3 ,fig4 #hi4 #ib4 ,l9es ( ,=ce ab\t a ,wire4 ,:5 a curr5t passes ?r\gh a wire1 ! magnetic ne$le plac$ ov] or "u x t5ds to take a position at "r angles to ! wire4 ,fig4 #hi %[s su* a wire & ne$le1 & h[ ! ne$le is deflect$2 x twi/s "r ar\nd f its ,n & ,s position z soon z ! curr5t beg9s to fl[4 ,?is %[s t ! l9es ( =ce pass ar\nd ! wire & n 9 ! direction ( its l5g?4 ,! ne$le does n sw+ entirely p]p5dicul> to ! wire1 t is1 to ! ,e & ,w l9e1 because ! e>? is at ! same "t pull+ its ,n pole t[>d ! ,n4 ,fig4 #ij %[s a b5t wire ?r\gh :i* a curr5t passes f ,c to ,z4 ,if y look along ! wire f ,c t[>d ! po9ts ,a & ,b1 y w see t "u ! wire ! l9es ( =ce pass to ! left4 ,look+ along ! wire f ,z t[>d ,d y w see t ! l9es ( =ce pass opposite to ! above1 z ! curr5t comes t[>d y4 ,?is is le>n$ by exp]im5t4 7,see ,/udy1 ,exp4 #aeb1 #che1 etc47 ,illu/ration3 ,fig4 #ij4 ,illu/ration3 ,fig4 #ia4 ,rule4 ,hold ! "r h& ) ! ?umb ext5d$ 7,fig4 #hi7 & ) ! f+]s po9t+ 9 ! direction ( ! curr5t1 ! palm be+ t[>d ! ne$le & on ! opposite side ( ! wire f ! ne$le4 ,! nor?-seek+ pole w !n be deflect$ 9 ! direction 9 :i* ! ?umb po9ts4 #ic4 ,curr5t ,detectors4 ,z !re is a magnetic field ab\t a wire :5 a curr5t passes ?r\gh x1 & z ! magnetic ne$le is affect$1 we h a means ( detect+ ! pres5ce ( a curr5t4 ,:5 ! curr5t is /rong x is simply necess>y to let x pass once ov] or "u a ne$le2 :5 x is weak1 ! wire mu/ pass sev]al times above & bel[ ! ne$le1 ,fig4 #ia1 to give ! ne$le motion4 7,see ,app>atus ,book1 ,*apt] ,,xiii41 = home-made detectors47 ,illu/ration3 ,fig4 #ib4 #id4 ,a/atic ,ne$les & ,detectors4 ,by arrang+ two magnetiz$ ne$les ) _! poles opposite ea* o!r1 ,fig4 #ib1 an a/atic ne$le is =m$4 ,! po9t+-p[] is almo/ no?+1 al?\gh _! magnetic fields are reta9$4 ,?is comb9ation is us$ to detect feeble curr5ts4 ,9 ! ord9>y detector1 ! t5d5cy ( ! ne$le to po9t to ! ,n & ,s has to be ov]come by ! magnetic field ab\t ! coil be=e ! ne$le c be mov$2 b 9 ! a/atic detector & galvanoscope ?is po9t+-p[] is done away )4 ,fig4 #ic %[s a simple a/atic galvanoscope4 ,fig4 #fg %[s an a/atic galvanomet] = measur+ weak curr5ts4 ,illu/ration3 ,fig4 #ic4 #ie4 ,pol>ity ( ,coils4 ,:5 a curr5t ( electricity passes ?r\gh a coil ( wire1 ! coil acts v mu* l a magnet1 al?\gh no iron ent]s into its con/ruction4 ,! coil becomes magnetiz$ by ! electric curr5t1 l9es ( =ce pass f x into ! air1 etc4 ,fig4 #id %[s a coil connect$ to copp] & z9c plates1 s arrang$ ) cork t ! :ole c float 9 a di% ( dilute sulphuric acid4 ,! curr5t passes z %[n by ! arr[s1 & :5 ! ,n pole ( a magnet is br\ght ne> ! "r-h& end1 !re is a repulsion1 %[+ t t end ( ! coil has a ,n pole4 ,rule4 ,:5 y face ! "r-h& end ( ! coil1 ! curr5t is se5 to pass ar\nd x 9 an anti-clockwise direction2 ?is produces a ,n pole4 ,:5 ! curr5t passes 9 a clockwise direction a ,s pole is produc$4 ,illu/ration3 ,fig4 #id4 #if4 ,electromagnets4 ,a coil ( wire has a /rong] field ?an a /raight wire c>ry+ ! same curr5t1 because ea* turn adds its field to ! fields ( ! o!r turns4 ,by hav+ ! c5tral "p ( ! coil made ( iron1 or by hav+ ! coil ( insulat$ wire w\nd ^u an iron core1 ! /r5g? ( ! magnetic field ( ! coil is greatly increas$4 ,l9es ( =ce d n pass z readily ?r\gh air z ?r\gh iron2 9 fact1 l9es ( =ce w g out ( _! way to g ?r\gh iron4 ,) a coil ( wire ! l9es ( =ce pass f its ,n pole ?r\gh ! air on all sides ( ! coil to its ,s pole2 !y !n pass ?r\gh ! inside ( ! coil & ?r\gh ! air back to ! ,n pole4 ,:5 ! resi/ance to _! passage ?r\gh ! coil is decreas$ by ! core1 ! magnetic field is greatly /r5g!n$1 & we h an electromagnet4 ,! coil ( wire tempor>ily magnetizes ! iron core2 x c p]man5tly magnetize a piece ( /eel us$ z a core4 7,see ,/udy1 ,*apt] ,,xxii41 = exp]im5ts47 ,illu/ration3 ,fig4 #ie4 #ig4 ,=ms ( ,electromagnets4 ,fig4 #ie %[s a /raight1 or b> electromagnet4 ,fig4 #if %[s a simple =m ( horse%oe electromagnet4 ,z ?is =m is n easily w\nd1 ! coils are g5]ally w\nd on two sep>ate cores :i* are !n jo9$ by a yoke4 ,! yoke m]ely takes ! place ( ! curv$ "p %[n 9 ,fig4 #if4 ,9 ,fig4 #ig is %[n ! ord9>y =m ( horse%oe electromagnet us$ = all sorts ( electrical in/rum5ts4 7,see ,app>atus ,book1 ,*apt] ,,ix41 = home-made electromagnets47 #ih4 ,yokes & ,armatures4 ,9 ! horse%oe magnet !re are two poles to attract & two to induce4 ,! l9es ( =ce pass ?r\gh ! yoke on _! way f "o core to ! o!r1 in/ead ( go+ ?r\gh ! air4 ,?is r$uces ! resi/ance to !m4 ,if we _h no yoke we %\ld simply h two /raight electromagnets1 & ! resi/ance to ! l9es ( =ce w\ld be s great t ! total /r5g? w\ld be mu* r$uc$4 ,yokes are made ( s(t iron1 z well z ! cores & armature4 ,! armature1 z ) p]man5t horse%oe magnets1 is /rongly drawn t[>d ! poles4 ,z soon z ! curr5t ceases to fl[1 ! attraction also ceases4 ,illu/ration3 ,fig4 #if4 ,illu/ration3 ,fig4 #ig4 ,illu/ration3 ,fig4 #ih4 ,beautiful magnetic figures c be made ) horse%oe magnets4 ,fig4 #ih %[s t ! coils mu/ be jo9$ s t ! curr5t c pass ar\nd ! cores 9 opposite directions to make unlike poles4 7,see ,/udy1 ,exp4 #afd to #agc47 ,,*apt] ,,xii4 ,,h[ ,,electricity ,,is ,,g5]at$ ,,by ,,induction4 #ii4 ,electromagnetic ,induction4 ,we h se5 t a magnet has ! p[] to act ?r\gh space & induce ano!r piece ( iron or /eel to become a magnet4 ,a *>ge ( /atic electricity c induce a *>ge ^u ano!r conductor4 ,we h n[ to see h[ a curr5t ( electricity 9 "o conductor c induce a curr5t 9 ano!r conductor1 n 9 any way connect$ ) ! fir/1 & h[ a magnet & a coil c g5]ate a curr5t4 ,illu/ration3 ,fig4 #ii4 ,illu/ration3 ,fig4 #ajj4 #ajj4 ,curr5t f ,magnet & ,coil4 ,if a b> magnet1 ,fig4 #ii1 be sudd5ly ?ru/ into a holl[ coil ( wire1 a mom5t>y curr5t ( electricity w be g5]at$ 9 ! coil4 ,no curr5t passes :5 ! magnet & coil are /ill2 at lea/ "o ( !m mu/ be 9 motion4 ,su* a curr5t is said to be induc$1 & is an inv]se "o :5 ! magnet is ins]t$1 & a direct "o :5 ! magnet is )drawn f ! coil4 #aja4 ,induc$ ,curr5ts & ,l9es ( ,=ce4 ,p]man5t magnets are con/antly s5d+ out ?\s&s ( l9es ( =ce4 ,fig4 #ajj %[s a b> magnet ent]+ a coil ( wire2 ! numb] ( l9es ( =ce is increas+1 & ! induc$ curr5t passes 9 an anti-clockwise direction :5 look+ d[n into ! coil along ! l9es ( =ce4 ,?is produces an indirect curr5t4 ,if an iron core be us$ 9 ! coil1 ! induc$ curr5t w be greatly /r5g!n$4 ,illu/ration3 ,fig4 #aja4 ,x takes =ce to move a magnet ?r\gh ! c5t] ( a coil1 & x is ?is "w t is ! s\rce ( ! induc$ curr5t4 ,we h1 9 ?is simple exp]im5t1 ! key to ! action ( ! dynamo & o!r electrical ma*9es4 #ajb4 ,curr5t f two ,coils4 ,fig4 #aja %[s two coils ( wire1 ! small] be+ connect$ to a cell1 ! l>g] to a galvanomet]4 ,by mov+ ! small coil up & d[n inside ( ! l>ge "o1 induc$ curr5ts are g5]at$1 fir/ 9 "o direction & !n 9 ! opposite4 ,we h "h two entirely sep>ate circuits1 9 no way connect$4 ,! prim>y curr5t comes f ! cell1 :ile ! second>y curr5t is an induc$ "o4 ,by plac+ a core 9 ! small coil ( ,fig4 #aja1 ! induc$ curr5t w be greatly /r5g!n$4 ,x is n necess>y to h ! two coils s t "o or bo? ( !m c move4 ,!y may be w\nd on ! same core1 or o!rwise arrang$ z 9 ! induction coil4 7,see ,/udy1 ,*apt] ,,xxv41 = exp]im5ts on induc$ curr5ts47 ,,*apt] ,,xiii4 ,,h[ ,,! ,,induction ,,coil ,,works4 #ajc4 ,! ,coils4 ,we saw1 #ajb1 t an induc$ curr5t 0 g5]at$ :5 a curr5t-c>ry+ coil1 ,fig4 #aja1 0 ?ru/ into ano!r coil connect$ ) a galvanomet]4 ,! galvanomet] 0 us$ m]ely to %[ ! pres5ce ( ! curr5t4 ,! prim>y coil is ! "o connect$ ) ! cell2 ! o!r "o is call$ ! second>y coil4 ,illu/ration3 ,fig4 #ajb4 ,:5 a curr5t sudd5ly beg9s to fl[ ?r\gh a coil1 ! effect ^u a neighbor+ coil is ! same z t produc$ by sudd5ly br++ a magnet ne> x2 & :5 ! curr5t /ops1 ! opposite effect is produc$4 ,x is evid5t1 !n1 t we c keep ! small coil ( ,fig4 #aja ) its core inside ( ! l>ge coil1 & g5]ate induc$ curr5ts by m]ely mak+ & break+ ! prim>y circuit4 ,we may consid] t :5 ! prim>y circuit is clos$1 ! l9es ( =ce %oot out ?r\gh ! turns ( ! second>y coil j z !y d :5 a magnet or a curr5t-c>ry+ coil is ?ru/ into x4 ,^u op5+ ! circuit1 ! l9es ( =ce cease to exi/2 t is1 we may imag9e !m drawn 9 aga94 #ajd4 ,con/ruction4 ,fig4 #ajb %[s "o =m ( home-made induction coil1 giv5 "h m]ely to expla9 ! action & connections4 ,ne>ly all induction coils h "s =m ( automatic curr5t int]rupt]1 plac$ 9 ! prim>y circuit1 to rapidly turn ! curr5t (f & on4 ,details ( ,figs4 #ajb & #ajc4 ,wires #e & #f are ! ends ( ! prim>y coil1 :ile wires #g & #h are ! t]m9als ( ! second>y coil4 ,! prim>y coil is w\nd on a bolt :i* s]ves z ! core1 & on ?is coil is w\nd ! second>y :i* consi/s ( _m turns ( f9e wire4 ,! wires f a batt]y %\ld be jo9$ to b9d+-po/s ,w & ,x1 & ! h&les1 f :i* ! %ock is felt1 to ,y & ,z4 ,fig4 #ajc %[s ! details ( ! int]rupt]4 ,illu/ration3 ,fig4 #ajc4 ,if ! curr5t f a cell ent]s at ,w1 x w pass ?r\gh ! prim>y coil & out at ,x1 aft] go+ ?r\gh #e1 ,r1 ,f1 ,s ,i1 ,b1 ,e & ,c4 ,! in/ant ! curr5t passes1 ! bolt becomes magnetiz$2 ?is attracts ,a1 :i* pulls ,b away f ! end ( ,s ,i1 ?us automatically op5+ ! circuit4 ,b at once spr+s back to its =m] position aga9/ ,,si1 z ,a is no long] attract$2 ! circuit be+ clos$1 ! op]ation is rapidly repeat$4 ,a cond5s] is usually connect$ to comm]cial =ms4 ,x is plac$ "u ! wood-"w & decreases sp>k+ at ! int]rupt]4 7,see ,app>atus ,book1 ,*apt] ,,xi41 = home-made induction coils47 ,illu/ration3 ,fig4 #ajd4 ,fig4 #ajd %[s "o =m ( coil4 ,! batt]y wires are jo9$ to ! b9d+-po/s at ! left4 ,! second>y coil ends 9 two rods1 & ! sp>k jumps f "o to ! o!r4 ,! int]rupt] & a swit* are %[n at ! left4 ,fig4 #aje %[s a small coil = m$ical purposes4 ,a dry cell is plac$ "u ! coil & all is includ$ 9 a neat box4 ,! h&les =m ! t]m9als ( ! second>y coil4 #aje4 ,! ,curr5ts4 ,x %\ld be not$ t ! curr5t f ! cell does n get into ! second>y coil4 ,! coils are ?or\ghly insulat$ f ea* o!r4 ,! second>y curr5t is an induc$ "o1 its voltage dep5d+ ^u ! relative numb] ( turns ( wire !re are 9 ! two coils4 7,see ,trans=m]s47 ,! second>y curr5t is an alt]nat+ "o2 t is1 x fl[s 9 "o direction = an in/ant & !n imm$iately rev]ses its direction4 ,! rapidity ( ! alt]nations dep5ds ^u ! spe$ ( ! int]rupt]4 ,coils are made t give a second>y curr5t ) an enorm\s voltage2 s high1 9 fact1 t ! sp>k w pass _m in*es1 & o!rwise act l ^? produc$ by /atic electric ma*9es4 ,illu/ration3 ,fig4 #aje4 #ajf4 ,uses ( ,induction ,coils4 ,gas-jets c be light$ at a di/ance ) ! sp>k f a coil1 by ext5d+ wires f ! second>y coil to ! jet4 ,p[d] c be fir$ at a di/ance1 & o!r ?+s p]=m$1 :5 a high voltage curr5t is ne$$4 ,its use 9 m$ic9e has be5 not$4 ,x is l>gely us$ 9 telephone "w4 ,( late1 great use has be5 made ( ! second>y curr5t 9 exp]im5ts ) vacuum-tubes1 ,x-ray "w1 etc4 ,,*apt] ,,xiv4 ,,! ,,electric ,,telegraph1 ,,& ,,h[ ,,x ,,s5ds ,,messages4 #ajg4 ,! ,complete ,telegraph ,l9e consi/s ( sev]al in/rum5ts1 swit*es1 etc41 etc41 b its ess5tial p>ts are3 ,! ,l9e1 or wire1 :i* connects ! diff]5t /ations2 ! ,transmitt] or ,key2 ! ,receiv] or ,s\nd]1 & ! ,batt]y or ,dynamo4 #ajh4 ,! ,l9e is made ( /rong copp]1 iron1 or s(t /eel wire4 ,to keep ! curr5t 9 ! l9e x is insulat$1 g5]ally ^u poles1 by glass insulators4 ,= v %ort l9es two wires c be us$1 ! l9e wire & ! return2 b = long l9es ! e>? is us$ z a return1 a wire f ea* end be+ jo9$ to l>ge metal plates sunk 9 ! e>?4 ,illu/ration3 ,fig4 #ajf4 #aji4 ,telegraph ,keys are m]ely in/rum5ts by :i* ! circuit c be conv5i5tly & rapidly op5$ or clos$ at ! w ( ! op]ator4 ,an ord9>y pu%-button may be us$ to turn ! curr5t (f & on1 b x is n s conv5i5t z a key4 ,fig4 #ajf %[s a side view ( a simple key :i* c be put any:]e 9 ! circuit1 "o end ( ! cut wire be+ atta*$ to ,x & ! o!r to ,y4 ,by mov+ ! lev] ,c up & d[n accord+ to a previ\sly arrang$ set ( signals1 a curr5t w be all[$ to pass to a di/ant /ation4 ,z ,x & ,y are insulat$ f ea* o!r1 ! curr5t c pass only :5 ,c presses aga9/ ,y4 ,fig4 #ajg %[s a regul> key1 ) swit*1 :i* is us$ to all[ ! curr5t to pass ?r\gh ! in/rum5t :5 receiv+ a message4 ,illu/ration3 ,fig4 #ajg4 #aaj4 ,telegraph ,s\nd]s receive ! curr5t f "s di/ant /ation1 & ) its electromagnet produce s\nds t c be translat$ into messages4 ,illu/ration3 ,fig4 #ajh4 ,fig4 #ajh %[s simply an electromagnet ,h1 ! coil be+ connect$ 9 s]ies ) a key ,k & a cell ,d ,c4 ,! key & ,d ,c are %[n by a top view4 ,! lev] ( ,k does n t\* ! o!r metal /rap until x is press$ d[n4 ,a little above ! core ( ,h is held a /rip ( iron1 on armature ,i4 ,z soon z ! circuit is clos$ at ,k1 ! curr5t ru%es ?r\gh ! circuit1 & ! core attracts ,i mak+ a di/9ct click4 ,z soon z ,k is rais$1 ,i spr+s away f ! core1 if x has be5 prop]ly held4 ,9 regul> in/rum5ts a click is also made :5 ! armature spr+s back aga94 ,! "t betwe5 ! two clicks c be %ort or long1 to repres5t dots or da%es1 :i*1 toge!r ) spaces1 repres5t lett]s4 7,= ,telegraph ,alphabet & complete directions = home-made keys1 s\nd]s1 etc41 see ,app>atus ,book1 ,*apt] ,,xiv47 ,illu/ration3 ,fig4 #aji4 ,illu/ration3 ,fig4 #aaj4 ,fig4 #aji %[s a =m ( home-made s\nd]4 ,fig4 #aaj %[s "o =m ( telegraph s\nd]4 ,ov] ! poles ( ! horse%oe electromagnet is an armature fix$ to a metal b> t c rock up & d[n4 ,! in/ant ! curr5t passes ?r\gh ! coils ! armature comes d[n until a /op-screw /rikes firmly ^u ! metal frame1 mak+ ! d[n click4 ,z soon z ! di/ant key is rais$1 ! armature is firmly pull$ back & ano!r click is made4 ,! two clicks diff] 9 s\nd1 & c be readily recogniz$ by ! op]ator4 #aaa4 ,connections = ,simple ,l9e4 ,fig4 #aaa %[s complete connections = a home-made telegraph l9e4 ,! capital lett]s are us$ = ! "r side1 ,r1 & small lett]s = ! left side1 ,l4 ,gravity cells1 ,b & b1 are us$4 ,! s\nd]s1 ,s & s1 & ! keys1 ,k & k1 are %[n by a top view4 ,! broad black l9es ( ,s & s repres5t ! armatures :i* are directly ov] ! electromagnets4 ,! keys h swit*es1 ,e & e4 ,! two /ations1 ,r & ,l1 may be 9 ! same room1 or 9 diff]5t h\ses4 ,! return wire1 ,r ,w1 passes f ! copp] ( b to ! z9c ( ,b4 ,?is is important1 z ! cells mu/ help ea* o!r2 t is1 !y are 9 s]ies4 ,! l9e wire1 ,l ,w1 passes f "o /ation to ! o!r1 & ! return may be ?r\gh ! wire1 ,r ,w1 or ?r\gh ! e>?2 b = %ort l9es a wire is be/4 ,illu/ration3 ,fig4 #aaa4 #aab4 ,op]ation ( ,simple ,l9e4 ,suppose two boys1 ,r 7"r7 & ,l 7left7 h a l9e4 ,fig4 #aaa %[s t ,r's swit*1 ,e1 is op51 :ile e is clos$4 ,! entire circuit1 !n1 is brok5 at b "o po9t4 ,z soon z ,r presses 8 key1 ! circuit is clos$1 & ! curr5t f bo? cells ru%es ar\nd f ,b1 ?r\gh ,k1 ,s1 ,l ,w1 s1 k1 b1 ,r ,w1 & back to ,b4 ,?is makes ! armatures ( ,s & s come d[n ) a click at ! same "t4 ,z soon z ! key is rais$1 ! armatures lift & make ! up-click4 ,z soon z ,r has f9i%$1 he closes 8 swit* ,e4 ,z ! armatures are !n held d[n1 ,l kn[s t ,r has f9i%$1 s he op5s 8 swit* e1 & answ]s ,r4 ,bo? ,e & e are clos$ :5 ! l9e is n 9 use1 s t ei!r c op5 8 swit* at any "t & call up ! o!r4 ,clos$ circuit cells mu/ be us$ = su* l9es4 ,on v l>ge l9es dynamos are us$ to furni% ! curr5t4 #aac4 ,! ,relay4 ,ow+ to ! l>ge resi/ance ( long telegraph l9es1 ! curr5t is weak :5 x rea*es a di/ant /ation1 & n /rong en\gh to "w an ord9>y s\nd]4 ,to get ar\nd ?is1 relays are us$2 ^! are v delicate in/rum5ts t replace ! s\nd] 9 ! l9e wire circuit4 ,_! coils are usually w\nd ) _m turns ( f9e wire1 s t a feeble curr5t w move its nicely adju/$ armature4 ,! relay armature m]ely acts z an automatic key to op5 & close a local circuit :i* includes a batt]y & s\nd]4 ,! l9e curr5t does n ent] ! s\nd]2 x passes back f ! relay to ! s5d+ /ation ?r\gh ! e>?4 ,illu/ration3 ,fig4 #aab4 ,fig4 #aab gives an idea ( simple relay connections4 ,! key ,k1 & cell ,d ,c1 repres5t a di/ant s5d+ /ation4 ,e is ! electromagnet ( ! relay1 & ,r ,a is its armature4 ,l ,w & ,r ,w repres5t ! l9e & return wires4 ,r ,a w vibrate t[>d ,e e "t ,k is press$1 & close ! local circuit1 :i* includes a local batt]y1 ,l ,b1 & a s\nd]4 ,x is evid5t t z soon z ,k is press$ ! s\nd] w "w ) a good /rong click1 z ! local batt]y c be made z /rong z desir$4 ,fig4 #aac %[s a regul> in/rum5t :i* op5s & closes ! local circuit at ! top ( ! armature4 ,illu/ration3 ,fig4 #aac4 #aad4 ,ink ,writ+ ,regi/]s are frequ5tly us$ in/ead ( s\nd]s4 ,fig4 #aad %[s a writ+ regi/] t />ts itself promptly at ! op5+ ( ! circuit1 & /ops automatically z soon z ! circuit returns to its normal condition4 ,a /rip ( n>r[ pap] is sl[ly pull$ f ! reel by ! ma*9e1 a m>k be+ made ^u x e "t ! armature ( an inclos$ electromagnet is attract$4 ,:5 ! circuit is simply clos$ = an in/ant1 a %ort l9e1 repres5t+ a dot1 is made4 ,regi/]s are built bo? s+le p5 & d\ble p54 ,9 ! latt] case1 z ! record ( "o wire is made ) a f9e p51 & ! o!r ) a co>se p51 !y c always be id5tifi$4 ,! record be+ block$ out ^u :ite tape 9 solid black color1 9 a s]ies ( clean-cut dots & da%es1 x c be read at a glance1 & z x is indelible1 x may be read ye>s aft]w>d4 ,regi/]s are made = local circuits1 = use 9 connection ) relays1 or = direct use on ma9 l9es1 z is usually desirable 9 fire-al>m circuits4 ,illu/ration3 ,fig4 #aad4 ,,*apt] ,,xv4 ,,! ,,electric ,,bell ,,& ,,"s ,,( ,,its ,,uses4 ,illu/ration3 ,fig4 #aae4 ,illu/ration3 ,fig4 #aaf4 #aae4 ,automatic ,curr5t ,int]rupt]s are us$ on mo/ common bells1 z well z on induction coils1 etc4 7,see #ajd47 ,fig4 #aae %[s a simple =m ( int]rupt]4 ,! wire #a1 f a cell ,d ,c1 is jo9$ to an iron /rip ,i a %ort di/ance f its end4 ,! o!r wire f ,d ,c passes to "o end ( ! electromagnet coil ,h4 ,! rema9+ end ( ,h is plac$ 9 contact ) ,i z %[n1 complet+ ! circuit4 ,z soon z ! curr5t passes1 ,i is pull$ d[n & away f ! upp] wire #b1 break+ ! circuit4 ,i1 be+ held by its left-h& end firmly 9 ! h&1 imm$iately spr+s back to its =m] position1 clos+ ! circuit aga94 ,?is action is repeat$1 ! rapidity ( ! vibrations dep5d+ some:at ^u ! position ( ! wires on ,i4 ,9 regul> in/rum5ts a plat9um po9t is us$ :]e ! circuit is brok52 ?is /&s ! sp>k+ :5 ! armature vibrates4 #aaf4 ,electric ,bells may be illu/rat$ by ref]r+ to ,fig4 #aaf1 :i* %[s a circuit simil> to t describ$ 9 #aae1 b :i* also conta9s a key ,k1 9 ! circuit4 ,?is all[s ! circuit to be op5$ & clos$ at a di/ance f ! vibrat+ armature4 ,! circuit mu/ n be brok5 at two places at ! same "t1 s wires %\ld t\* at ! end ( ,i be=e press+ ,k4 ,^u press+ ,k ! armature ,i w vibrate rapidly4 ,by plac+ a small bell ne> ! end ( ! vibrat+ armature1 s t x w be /ruck by ,i at ea* vibration1 we %\ld h a simple electric bell4 ,?is =m ( electric bell is call$ a trembl+ bell1 on acc\nt ( its vibrat+ armature4 ,illu/ration3 ,fig4 #aag4 ,illu/ration3 ,fig4 #aah4 ,fig4 #aag %[s a =m ( trembl+ bell ) cov] remov$4 ,fig4 #aah %[s a s+le-/roke bell1 us$ = fire-al>ms & o!r signal "w4 ,9 ?is ! armature is attract$ b once ea* "t ! curr5t passes4 ,z _m taps ( ! bell c be giv5 z desir$ by press+ ! pu%-button4 ,fig4 #aai %[s a gong = railway cross+s1 signals1 etc4 ,fig4 #abj %[s a circuit includ+ cell1 pu%-button1 & bell1 ) extra wire = l5g!n+ ! l9e4 ,illu/ration3 ,fig4 #aai4 ,electro-,me*anical ,gongs are us$ to give l\d signals = special purposes4 ,! me*anical device is />t$ by ! electric curr5t :5 ! armature ( ! electromagnet is attract$4 ,spr+s1 weights1 etc41 are us$ z ! p[]4 ,fig4 #aba %[s a small bell ( ?is k9d4 ,illu/ration3 ,fig4 #abj4 #aag4 ,magneto ,te/+ ,bells1 ,fig4 #abb1 are really small h&-p[] dynamos4 ,! armature is made to revolve betwe5 ! poles ( /rong p]man5t magnets1 & x is s w\nd t x gives a curr5t ) a l>ge ,e4 ,m4 ,f41 s t x c r+ ?r\gh ! l>ge resi/ance ( a long l9e to te/ x4 ,magneto ,signal ,bells1 ,fig4 #abc1 are us$ z g5]ator & bell 9 connection ) telephones4 ,! g5]ator1 us$ to r+ a bell at a di/ant /ation1 /&s at ! bottom ( ! box4 ,! bell is fa/5$ to ! lid1 & receives curr5t f a di/ant bell4 ,illu/ration3 ,fig4 #aba4 ,illu/ration3 ,fig4 #abb4 ,illu/ration3 ,fig4 #abc4 ,illu/ration3 ,fig4 #abd4 #aah4 ,electric ,buzz]s h ! same g5]al con/ruction z electric bells2 9 fact1 y w h a buzz] by remov+ ! bell f an ord9>y electric bell4 ,buzz]s are us$ 9 places :]e ! l\d s\nd ( a bell w\ld be objectionable4 ,fig4 #abd %[s ! usual =m ( buzz]s1 ! cov] be+ remov$4 ,,*apt] ,,xvi4 ,,! ,,telephone1 ,,& ,,h[ ,,x ,,transmits ,,spee*4 #aai4 ,! ,telephone is an in/rum5t = reproduc+ s\nds at a di/ance1 & electricity is ! ag5t by :i* ?is is g5]ally accompli%$4 ,! "p spok5 to is call$ ! transmitt]1 & ! "p :i* gives s\nd out aga9 is call$ ! receiv]4 ,s\nd itself does n pass ov] ! l9e4 ,:ile ! same app>atus c be us$ = bo? transmitt] & receiv]1 !y are g5]ally diff]5t 9 con/ruction to get ! be/ results4 ,illu/ration3 ,fig4 #abe4 ,illu/ration3 ,fig4 #abf4 ,illu/ration3 ,fig4 #abg4 #abj4 ,! ,bell or ,magneto-transmitt] g5]ates its own curr5t1 & is1 /rictly speak+1 a dynamo t is run by ! voice4 ,x dep5ds ^u induction = its action4 ,illu/ration3 ,fig4 #abh4 ,fig4 #abe %[s a coil ( wire1 ,h1 ) s(t iron core1 ! ends ( ! wires be+ connect$ to a delicate galvanoscope4 ,if "o pole ( ! magnet ,h ,m be sudd5ly mov$ up & d[n ne> ! core1 an alt]nat+ curr5t w be g5]at$ 9 ! coil1 ! circuit be+ complet$ ?r\gh ! galvanoscope4 ,z ,h ,m approa*es ! core ! curr5t w fl[ 9 "o direction1 & z ,h ,m is )drawn x w pass 9 ! opposite direction4 ,! comb9ation makes a m9iature alt]nat+ dynamo4 ,illu/ration3 ,fig4 #abi4 ,if we imag9e ! s(t iron core ( ,h1 ,fig4 #abe1 tak5 out1 & "o pole ( ,h ,m1 or pref]ably t ( a b> magnet /uck ?r\gh ! coil1 a feeble curr5t w also be produc$ by mov+ ! s(t iron back & =? ne> ! magnet's pole4 ,?is is really :at is done 9 ! ,bell transmitt]1 s(t iron 9 ! %ape ( a ?9 disc 7,d1 ,fig4 #abf7 be+ made to vibrate by ! voice imm$iately 9 front ( a coil hav+ a p]man5t magnet = a core4 ,! disc1 or diaphragm1 z x is call$1 is fix$ ne>1 b x does n t\*1 ! magnet4 ,x is "u a con/ant /ra91 be+ attract$ by ! magnet1 s its slighte/ movem5t *anges ! /r5g? ( ! magnetic field1 caus+ m or less l9es ( =ce to %oot ?r\gh ! turns ( ! coil & induce a curr5t4 ,! coil consi/s ( _m turns ( f9e1 insulat$ wire4 ,! curr5t g5]at$ is an alt]nat+ "o1 & al?\gh exce$+ly small c =ce its way ?r\gh a long l5g? ( wire4 ,illu/ration3 ,fig4 #acj4 ,fig4 #abg %[s a section ( a regul> transmitt]1 & ,fig4 #abh a =m ( comp\nd magnet frequ5tly us$ 9 ! transmitt]4 ,fig4 #abi %[s a transmitt] ) cords :i* conta9 flexible wires4 ,illu/ration3 ,fig4 #aca4 #aba4 ,! ,receiv]1 = %ort l9es1 may h ! same con/ruction z ! ,bell transmitt]4 ,fig4 #acj %[s a diagram ( two ,bell receiv]s1 ei!r be+ us$ z ! transmitt] & ! o!r z ! receiv]4 ,z ! alt]nat+ curr5t goes to ! di/ant receiv]1 x flies ?r\gh ! coil fir/ 9 "o direction & !n 9 ! o!r4 ,?is alt]nately /r5g!ns & weak5s ! magnetic field ne> ! diaphragm1 caus+ x to vibrate back & =? z ! magnet pulls m or less4 ,! receiv] diaphragm repeats ! vibrations 9 ! transmitt]4 ,no?+ b ! induc$ electric curr5t passes ov] ! wires4 ,illu/ration3 ,fig4 #acb4 #abb4 ,! ,microphone4 ,if a curr5t ( electricity be all[$ to pass ?r\gh a circuit l t %[n 9 ,fig4 #aca1 :i* includes a batt]y1 a ,bell receiv]1 & a microphone1 any slight s\nd ne> ! microphone w be greatly magnifi$ 9 ! receiv]4 ,! microphone consi/s ( pieces ( c>bon s fix$ t !y =m loose contacts4 ,any slight movem5t ( ! c>bon causes ! resi/ance to ! curr5t to be greatly *ang$4 ,! rapidly v>y+ resi/ance all[s m or less curr5t to pass1 ! result be+ t ?is pulsat+ curr5t causes ! diaphragm to vibrate4 ,! diaphragm has a con/antly v>y+ pull ^u x :5 ! c>bons are 9 any way di/urb$ by ! voice1 or by ! tick+ ( a wat*1 etc4 ,?is pr9ciple has be5 made use ( 9 c>bon transmitt]s1 :i* are made 9 a l>ge v>iety ( =ms4 ,illu/ration3 ,fig4 #acc4 #abc4 ,! ,c>bon ,transmitt] does n1 9 itself1 g5]ate a curr5t l ! magneto-transmitt]2 x m]ely produces *anges 9 ! /r5g? ( a curr5t t fl[s ?r\gh x & t comes f "s outside s\rce4 ,9 ,fig4 #acb1 ,x & ,y are two c>bon buttons1 ,x be+ atta*$ to ! diaphragm ,d4 ,button ,y presses g5tly aga9/ ,x1 all[+ a little curr5t to pass ?r\gh ! circuit :i* includes a batt]y1 ,d ,c1 & a receiv]1 ,r4 ,:5 ,d is caus$ to vibrate by ! voice1 ,x is made to press m or less aga9/ ,y1 & ?is all[s m or less curr5t to pass ?r\gh ! circuit4 ,?is direct undulat+ curr5t *anges ! pull ^u ! diaphragm ( ,r1 caus+ x to vibrate & reproduce ! orig9al s\nds spok5 into ! transmitt]4 ,9 regul> l9es1 ( c\rse1 a receiv] & transmitt] are connect$ at ea* end1 toge!r ) bells1 etc41 = signal+4 ,illu/ration3 ,fig4 #acd4 #abd4 ,induction ,coils 9 ,telephone ,"w4 ,z ! resi/ance ( long telephone l9es is great1 a high electrical pressure1 or ,e4,m4,f4 is desir$4 ,:ile ! curr5t f "o or two cells is suffici5t to "w ! transmitt] prop]ly1 & cause undulat+ curr5ts 9 ! %ort l9e1 x does n h p[] en\gh to =ce its way ov] a long l9e4 ,to get ar\nd ?is difficulty1 an induction coil1 ,fig4 #acc1 is us$ to trans=m ! batt]y curr5t1 t fl[s ?r\gh ! c>bon transmitt] & prim>y coil1 into a curr5t ) a high ,e4 ,m4 ,f4 ,! batt]y curr5t 9 ! prim>y coil is undulat+1 b always passes 9 ! same direction1 mak+ ! magnetic field ar\nd ! core weak] & /rong]4 ,?is causes an alt]nat+ curr5t 9 ! second>y coil & ma9 l9e4 ,9 ,fig4 #acc ,p & ,s repres5t ! prim>y & second>y coils4 ,p is jo9$ 9 s]ies ) a cell & c>bon transmitt]2 ,s is jo9$ to ! di/ant receiv]4 ,"o end ( ,s c be gr\nd$1 ! curr5t complet+ ! circuit ?r\gh ! e>? & into ! receiv] ?r\gh ano!r wire ent]+ ! e>?4 ,illu/ration3 ,fig4 #ace4 #abe4 ,v>i\s =ms ( telephones are %[n 9 ,figs4 #acd1 #ace1 #acf4 ,fig4 #acd %[s a =m ( desk telephone2 ,fig4 #ace %[s a common =m ( wall telephone2 ,fig4 #acf %[s head-telephones = swit*bo>d op]ators4 ,illu/ration3 ,fig4 #acf4 ,,*apt] ,,xvii4 ,,h[ ,,electricity ,,is ,,g5]at$ ,,by ,,dynamos4 #abf4 ,! ,dynamo1 ,dynamo-,electric ,ma*9e or ,g5]ator1 is a ma*9e = conv]t+ me*anical en]gy into an electric curr5t1 ?r\gh electromagnetic induction4 ,! dynamo is a ma*9e t w conv]t /eam p[]1 = example1 into an electric curr5t4 ,/rictly speak+1 a dynamo creates electrical pressure1 or electromotive =ce1 & n electricity1 j z a =ce-pump creates wat]-pressure1 & n wat]4 ,!y are g5]ally run by /eam or wat] p[]4 ,illu/ration3 ,fig4 #acg4 #abg4 ,induc$ ,curr5ts4 ,we h already spok5 ab\t curr5ts be+ induc$ by mov+ a coil ( wire 9 a magnetic field4 ,we %all n[ see h[ ?is pr9ciple is us$ 9 ! dynamo :i* is a g5]ator ( induc$ curr5ts4 ,illu/ration3 ,fig4 #ach4 ,fig4 #acg %[s h[ a curr5t c be g5]at$ by a b> magnet & a coil ( wire4 ,fig4 #ach %[s h[ a curr5t c be g5]at$ by a horse%oe magnet & a coil ( wire hav+ an iron core4 ,! ends ( ! coil are to be connect$ to an a/atic galvanoscope2 ?is =ms a clos$ circuit4 ,! coil may be mov$ pa/ ! magnet1 or ! magnet pa/ ! coil4 ,illu/ration3 ,fig4 #aci4 ,illu/ration3 ,fig4 #adj4 ,illu/ration3 ,fig4 #ada4 ,illu/ration3 ,fig4 #adb4 ,fig4 #aci %[s h[ a curr5t c be g5]at$ by two coils1 ,h be+ connect$ to an a/atic galvanoscope & ,e to a batt]y4 ,by sudd5ly br++ ,e t[>d ,h or ! core ( ,e pa/ t ( ,h1 a curr5t is produc$4 ,we h 9 ?is arrangem5t ! ma9 features ( a dynamo4 ,we c rev]se ! op]ation1 hold+ ,e 9 "o position & mov+ ,h rapidly t[>d x4 ,9 ?is case ,h w\ld repres5t ! armature & ,e ! field-magnet4 ,:5 ,h is mov$ t[>d ,e1 ! induc$ curr5t 9 ,h fl[s 9 "o direction1 & :5 ,h is sudd5ly )drawn f ,e ! curr5t is rev]s$ 9 ,h4 7,see ,/udy1 ,*apt] ,,xxv41 = exp]im5ts47 ,illu/ration3 ,fig4 #adc4 #abh4 ,induc$ ,curr5ts by ,rot>y ,motion4 ,! motions ( ! coils 9 /raight l9es are n suitable = produc+ curr5ts /rong en\gh = comm]cial purposes4 ,9 ord] to g5]ate curr5ts ( consid]able /r5g? & pressure1 ! coils ( wire h to be pu%$ pa/ magnets1 or electromagnets1 ) great spe$4 ,9 ! dynamo ! coils are s w\nd t !y c be giv5 a rapid rot>y motion z !y fly pa/ /rong electromagnets4 ,9 ?is way ! coil c keep on pass+ ! same magnets1 9 ! same direction1 z long z =ce is appli$ to ! %aft t c>ries !m4 ,illu/ration3 ,fig4 #add4 #abi4 ,field-,magnets2 ,armature2 ,commutator4 ,:at we ne$ !n1 to produce an induc$ curr5t by a rot>y motion1 is a /rong magnetic field1 a rotat+ coil ( wire prop]ly plac$ 9 ! field1 & "s means ( lead+ ! curr5t f ! ma*9e4 ,illu/ration3 ,fig4 #ade4 ,illu/ration3 ,fig4 #adf4 ,if a loop ( wire1 ,fig4 #adj1 be s arrang$ on be>+s at its ends t x c be made to revolve1 a curr5t w fl[ ?r\gh x 9 "o direction dur+ "o-half ( ! revolution1 & 9 ! opposite direction dur+ ! o!r half1 x be+ insulat$ f all ext]nal conductors4 ,?is agrees ) ! exp]im5ts sugge/$ 9 #abg1 :5 ! curr5t g5]at$ 9 a coil pass$ 9 "o direction dur+ its motion t[>d ! /ronge/ "p ( ! field1 & 9 ! opposite direction :5 ! coil pass$ out ( x4 ,a coil mu/ be cut by l9es ( =ce to g5]ate a curr5t4 ,a curr5t inside ( ! ma*9e1 z 9 ,fig4 #adj1 w\ld be ( no value2 x mu/ be l$ out to ext]nal conductors :]e x c d "w4 ,"s sort ( slid+ contact is necess>y to connect a revolv+ conductor ) outside /ation>y ones4 ,! magnet1 call$ ! field-magnet1 is m]ely to furni% l9es ( magnetic =ce4 ,! "o turn ( wire repres5ts ! simple/ =m ( armature4 ,fig4 #ada %[s ! ends ( a coil jo9$ to two r+s1 ,x1 ,y1 insulat$ f ea* o!r1 & rotat+ ) ! coil4 ,! two /ation>y pieces ( c>bon1 ,a1 ,b1 call$ bru%es1 press aga9/ ! r+s1 & to ^! are jo9$ wires1 :i* complete ! circuit1 & :i* lead out :]e ! curr5t c d "w4 ,! arr[s %[ ! direction ( ! curr5t dur+ "o-half ( a revolution4 ,! r+s =m a collector1 & ?is arrangem5t gives an alt]nat+ curr5t4 ,illu/ration3 ,fig4 #adg4 ,9 ,fig4 #adb ! ends ( ! coil are jo9$ to ! two halves ( a cyl9d]4 ,^! halves1 ,x & ,y1 are insulat$ f ea* o!r1 & f ! axis4 ,! curr5t fl[s f ,x onto ! bru% ,a1 ?r\gh "s ext]nal circuit1 to d ! "w1 & !nce back ?r\gh bru% ,b onto ,y4 ,by ! "t t ,y gets ar\nd to ,a1 ! direction ( ! curr5t 9 ! loop has rev]s$1 s t x passes t[>d ,y1 b x /ill ent]s ! outside circuit ?r\gh ,a1 because ,y is !n 9 contact ) ,a4 ,?is device is call$ a commutator1 & x all[s a con/ant or direct curr5t to leave ! ma*9e4 ,illu/ration3 ,fig4 #adh4 ,9 regul> ma*9es1 ! field-magnets are electromagnets1 ! :ole or a "p ( ! curr5t f ! dynamo pass+ ar\nd !m on its way out1 to excite !m & make a p[]ful field betwe5 ! poles4 ,to less5 ! resi/ance to ! l9es ( =ce on _! way f ! ,n to ! ,s pole ( ! field-magnets1 ! armature coils are w\nd on an iron core2 ?is greatly increases ! /r5g? ( ! field1 z ! l9es ( =ce h to jump across b two small air-gaps4 ,!re are _m loops ( wire on regul> armatures1 & _m segm5ts to ! commutator1 c>efully insulat$ f ea* o!r1 ea* gett+ its curr5t f ! coil atta*$ to x4 #acj4 ,types ( ,dynamos4 ,:ile !re is an almo/ endless numb] ( diff]5t makes & %apes ( dynamos1 !y may be divid$ into two great types2 ! cont9u\s or direct curr5t1 & ! alt]nat+ curr5t dynamo4 ,direct curr5t ma*9es give out a curr5t :i* con/antly fl[s 9 "o direction1 & ?is is because a commutator is us$4 ,alt]nat+ curr5ts come f collectors or r+s1 z %[n 9 ,fig4 #ada2 & z an alt]nat+ curr5t _c be us$ to excite ! fields1 an outside curr5t f a small direct curr5t ma*9e mu/ be us$4 ,^! are call$ excit]s4 ,illu/ration3 ,fig4 #adi4 ,9 direct curr5t ma*9es en\gh residual magnetism is left 9 ! field to induce a slight curr5t 9 ! armature :5 ! ma*9e is />t$4 ,?is imm$iately adds /r5g? to ! field-magnets1 :i*1 9 turn1 induce a /rong] curr5t 9 ! armature4 #aca4 ,w9d+ ( ,dynamos4 ,!re are sev]al ways ( w9d+ dynamos1 dep5d+ ^u ! special uses to be made ( ! curr5t4 ,! s]ies w\nd dynamo1 ,fig4 #adc1 is s arrang$ t ! entire curr5t passes ar\nd ! field-magnet cores on its way f ! ma*9e4 ,9 ! %unt w\nd dynamo1 ,fig4 #add1 a "p1 only1 ( ! curr5t f ! ma*9e is c>ri$ ar\nd ! field-magnet cores ?r\gh _m turns ( f9e wire4 ,! comp\nd w\nd dynamo is really a comb9ation ( ! two me?ods j giv54 ,9 sep>ately-excit$ dynamos1 ! curr5t f a sep>ate ma*9e is us$ to excite ! field-magnets4 #acb4 ,v>i\s ,ma*9es4 ,fig4 #ade %[s a h& p[] dynamo :i* produces a curr5t = exp]im5tal "w4 ,fig4 #adf %[s a magneto-electrical g5]ator :i* produces a curr5t = m$ical use4 ,figs4 #adg1 #adh %[ =ms ( dynamos1 & ,fig4 #adi %[s h[ arc lamps are connect$ 9 s]ies to dynamos4 ,illu/ration ,,*apt] ,,xviii4 ,,h[ ,,! ,,electric ,,curr5t ,,is ,,trans=m$4 #acc4 ,electric ,curr5t & ,"w4 ,! am\nt ( "w a curr5t c d dep5ds ^u two factors2 ! /r5g? 7amp]es71 & ! pressure1 or ,e4 ,m4 ,f4 7volts74 ,a curr5t ( #aj amp]es ) a pressure ( #a1jjj volts #aj #a1jjj #aj1jjj watts4 ,?is furni%es ! same am\nt ( en]gy z a curr5t ( #ej amp]es at #bjj volts2 #ej #bjj #aj1jjj watts4 #acd4 ,transmission ( ,curr5ts4 ,x is (t5 necess>y to c>ry a curr5t a long di/ance be=e x is us$4 ,a curr5t ( #ej amp]es w\ld ne$ a copp] conductor #be times z l>ge 7sectional area7 z "o to c>ry ! #aj amp]e curr5t m5tion$ 9 #acc4 ,z copp] conductors are v exp5sive1 electric light companies1 etc41 g5]ally try to c>ry ! curr5t on z small a wire z possible4 ,to d ?is1 ! voltage is kept high1 & ! amp]age l[4 ,?us1 z se5 9 #acc1 ! curr5t ( #a1jjj volts & #aj amp]es c\ld be c>ri$ on a mu* small] wire ?an ! o!r curr5t ( equal en]gy4 ,a curr5t ( #a1jjj volts1 h[ev]1 is n adapt$ = lights1 etc41 s x has to be *ang$ to l[] voltage by "s =m ( trans=m] be=e x c be us$4 #ace4 ,trans=m]s1 l induction coils1 are in/rum5ts = *ang+ ! ,e4 ,m4 ,f4 & /r5g? ( curr5ts4 ,!re is v little loss ( en]gy 9 well-made trans=m]s4 ,!y consi/ ( two coils ( wire on "o core2 9 fact1 an induction coil may be consid]$ a trans=m]1 b 9 ?is a direct curr5t has to be int]rupt$4 ,if ! second>y coil has #ajj times z _m turns ( wire z ! prim>y1 a curr5t ( #ajj volts c be tak5 f ! second>y coil :5 ! prim>y curr5t is b #a volt2 b ! /r5g? 7amp]es7 ( ?is new curr5t w be b "o-hundr$? t ( ! prim>y curr5t4 ,by us+ ! coil ( f9e wire z ! prim>y1 we c l[] ! voltage & increase ! /r5g? 9 ! same proportion4 ,illu/ration3 ,fig4 #aej4 ,illu/ration3 ,fig4 #aea4 ,fig4 #aej %[s ab\t ! simple/ =m ( trans=m] ) a solid iron core1 on :i* are w\nd two coils1 ! "o1 ,p1 be+ ! prim>y1 & ! o!r1 ,s1 ! second>y4 ,fig4 #aea %[s ! g5]al appe>ance ( "o make ( trans=m]4 ,! op]ation ( ?is app>atus1 z already m5tion$1 is to r$uce ! high pressure alt]nat+ curr5t s5t out ov] ! conductors f ! dynamo1 to a pot5tial at :i* x c be employ$ ) conv5i5ce & safety1 = illum9ation & o!r purposes4 ,!y consi/ ( two or m coils ( wire mo/ c>efully insulat$ f "o ano!r4 ,a core or magnetic circuit ( s(t iron1 compos$ ( v ?9 pun*+s1 is !n =m$ ar\nd ^! coils1 ! purpose ( ! iron core be+ to r$uce ! magnetic resi/ance & increase ! inductive effect4 ,"o set ( ^! coils is connect$ ) ! prim>y or high-pressure wires1 :ile ! o!r set1 :i* are call$ ! second>y coils1 is connect$ to ! h\se or l[-pressure wires1 or :]ev] ! curr5t is requir$ = use4 ,! rapidly alt]nat+ curr5t impulses 9 ! prim>y or high-pressure wires induce second>y curr5ts simil> 9 =m b opposite 9 direction 9 ! second>y coils4 ,^! curr5t impulses are ( a mu* l[] pressure1 dep5d+ ^u ! ratio ( ! numb] ( turns ( wire 9 ! respective coils1 x be+ cu/om>y to w9d trans=m]s 9 su* a mann] z to r$uce f #a1jjj or #b1jjj-volt prim>ies to #ej or #ajj-volt second>ies1 at :i* voltage ! second>y curr5t is p]fectly h>mless4 ,illu/ration3 ,fig4 #aeb4 #acf4 ,motor-,dynamos4 ,fig4 #aeb4 ,^! consi/ ess5tially ( two belt-type ma*9es on a common base1 direct c\pl$ toge!r1 "o ma*9e act+ z a motor to receive curr5t at a c]ta9 voltage1 & ! o!r act+ z a dynamo to give out ! curr5t usually at a diff]5t voltage4 ,z !y trans=m curr5t f "o voltage to ano!r1 motor-dynamos are sometimes call$ ,d\ble ,field ,direct ,curr5t ,trans=m]s4 ,! l>g] sizes h ?ree be>+s1 "o be>+ be+ betwe5 ! two ma*9es1 :ile ! small] sizes h b two be>+s1 ! two armatures be+ fa/5$ to a common spid]4 ,illu/ration3 ,fig4 #aec4 ,applications4 ,! uses to :i* motor-dynamos are put are v v>i\s4 ,!y are ext5sively us$ 9 ! l>g] sizes z ,boo/]s1 = giv+ ! necess>y extra =ce on long electric supply circuits to c>ry ! curr5t to ! end ) ! same pressure z t :i* rea*es ! ends ( ! %ort] circuits f ! /ation4 ,motor-dynamos h ! advantage ov] dynamotors1 describ$ lat]1 ( hav+ ! second>y voltage easily & economically v>i$ ov] wide ranges by means ( a regulator 9 ! dynamo field4 #acg4 ,dynamotors4 ,fig4 #aec4 ,9 ,dynamotors ! motor & dynamo armatures are comb9$ 9 "o1 ?us requir+ a s+le field only4 ,! prim>y armature w9d+1 :i* op]ates z a motor to drive ! ma*9e1 & ! second>y or dynamo w9d+1 :i* op]ates z a g5]ator to produce a new curr5t1 are ^u ! same armature core1 s t ! armature reaction ( "o w9d+ neutralizes t ( ! o!r4 ,!y !re=e h no t5d5cy to sp>k1 & d n require %ift+ ( ! bru%es ) v>y+ load4 ,hav+ b "o field & two be>+s1 !y are also m effici5t ?an motor-dynamos4 ,applications4 ,!y h l>gely displac$ batt]ies = telegraph "w4 ,! size %[n1 occupy+ a space ( ab\t #h-;in* cube1 & hav+ an output ( #dj watts1 w displace ab\t #hjj gravity cells1 occupy+ a space ( ab\t #aj feet cube4 ,! co/ ( ma9t5ance ( su* a batt]y p] ye>1 exclusive ( r5t1 is ab\t #hjj1 :]eas ! #a-f dynamotor c be op]at$ at an annual exp5se ( #aej4 ,dynamotors are l>gely us$ by telephone companies = *>g+ /orage batt]ies1 & = trans=m+ f direct to alt]nat+ curr5t1 = r++ telephone bells4 ,electro-caut]y1 electroplat+1 & electric heat+ also give use to dynamotors4 ,,*apt] ,,xix4 ,,h[ ,,electric ,,curr5ts ,,are ,,di/ribut$ ,,= ,,use4 ,illu/ration3 ,fig4 #aed4 ,illu/ration3 ,fig4 #aee4 ,illu/ration3 ,fig4 #aef4 #ach4 ,conductors & ,insulators4 ,to c>ry ! p[]ful curr5t f ! g5]at+ /ation to di/ant places :]e x is to give heat1 p[]1 or light1 or ev5 to c>ry ! small curr5t ( a s+le cell f "o room to ano!r1 conductors mu/ be us$4 ,to keep ! curr5t f pass+ into ! e>? be=e x rea*es its de/9ation insulators mu/ be us$4 ,! =m ( conductors & insulators us$ w dep5d ^u ! curr5t & _m o!r conditions4 ,x %\ld be rememb]$ t ! curr5t has to be c>ri$ to ! lamp or motor1 ?r\gh :i* x passes1 & !n back aga9 to ! dynamo1 to =m a complete circuit4 ,a break any:]e 9 ! circuit /ops ! curr5t4 ,insulators are z important z conductors4 ,illu/ration3 ,fig4 #aeg4 ,illu/ration3 ,fig4 #aeh4 #aci4 ,ma9s1 ,s]vice ,wires1 etc4 ,f ! swit*bo>d ! curr5t fl[s out ?r\gh ! /reets 9 l>ge conductors1 or ma9s1 ! supply be+ kept up by ! dynamos1 j z wat]-pressure is kept up by ! con/ant work+ ( pumps4 ,bran*es1 call$ s]vice wires1 are l$ (f f ! ma9s to supply h\ses or factories1 "o wire lead+ ! curr5t into ! h\se f "o ma91 & a simil> "o lead+ x out ( ! h\se aga9 to ! o!r ma94 ,illu/ration3 ,fig4 #aei4 ,illu/ration3 ,fig4 #afj4 ,9 l>ge build+s1 pairs ( wires1 call$ ris]s1 bran* out f ! s]vice wires & c>ry ! curr5t up ?r\gh ! build+4 ,^! h /ill o!r bran*es--floor ma9s1 etc41 t pass ?r\gh halls1 etc41 small] bran*es f9ally rea*+ ! lamps4 ,! sizes ( all ( ^! wires dep5d ^u h[ mu* curr5t has to pass ?r\gh !m4 ,! ma9s 9 l>ge cities are usually plac$ und]gr\nd4 ,9 "s places !y are c>ri$ on poles4 ,illu/ration3 ,fig4 #afa4 #adj4 ,electric ,conduits are und]gr\nd passages = electric wires1 cables1 etc4 ,!re are sev]al ways ( insulat+ ! conductors4 ,sometimes !y are plac$ 9 e>!nw>e or iron tubes1 or 9 wood t has be5 treat$ to make x wat]-pro(4 ,at %ort di/ances are plac$ man-holes1 :]e ! diff]5t l5g?s are jo9$1 & :]e bran*es are atta*$4 ,illu/ration3 ,fig4 #afb4 ,fig4 #aed %[s creosot$ wood5 pipes2 ,fig4 #aee %[s ano!r =m ( wood5 pipe4 ,fig4 #aef %[s a c\pl+-box us$ to jo9 ,edison tubes4 ,! ?ree wires1 us$ 9 ! ?ree-wire sy/em1 are insulat$ f ea* o!r1 ! :ole be+ surr\nd$ by an iron pipe ( conv5i5t l5g? = h&l+4 ,fig4 #aeg %[s sections ( man-holes & v>i\s devices us$ 9 conduit "w4 ,illu/ration3 ,fig4 #afc4 #ada4 ,miscellane\s ,appliances4 ,:5 ! curr5t ent]s a h\se = inc&esc5t light+ purposes1 = example1 q a numb] ( ?+s are necess>y4 ,to measure ! curr5t a met] is usually plac$ 9 ! cell>4 ,9 new h\ses ! insulat$ conductors are usually run ?r\gh "s sort ( tube :i* acts z a d\ble protection1 all be+ hidd5 f view4 ,fig4 #aeh %[s a %ort l5g? ( iron tube ) a l9+ ( insulat+ mat]ial4 ,wires are (t5 run ?r\gh tubes made ( rubb] & v>i\s o!r insulat+ mat]ials4 ,:]e ! curr5t is to be put into h\ses aft] ! pla/]+ has be5 done1 ! wires are usually run ?r\gh m\ld+s or support$ by cleats4 ,fig4 #aei %[s a cross-section ( m\ld+4 ,! insulat$ wires are plac$ 9 ! slots1 :i* are !n cov]$4 ,illu/ration3 ,fig4 #afd4 ,illu/ration3 ,fig4 #afe4 ,illu/ration3 ,fig4 #aff4 ,illu/ration3 ,fig4 #afg4 ,fig4 #afj %[s a =m ( porcela9 cleat4 ,^! are fa/5$ to ceil+s or walls1 & firmly hold ! insulat$ wires 9 place4 ,fig4 #afa %[s a wood cleat4 ,fig4 #afb %[s small porcela9 insulators4 ,^! may be screw$ to walls1 etc41 ! wire be+ !n fa/5$ to !m4 ,fig4 #afc %[s h[ telegraph wires are support$ & insulat$4 ,fig4 #afd %[s h[ wires may be c>ri$ by tree & insulat$ f !m4 ,illu/ration3 ,fig4 #afh4 ,illu/ration3 ,fig4 #afi4 ,illu/ration3 ,fig4 #agj4 #adb4 ,safety ,devices4 ,we h se5 t :5 too l>ge a curr5t passes ?r\gh a wire1 ! wire becomes heat$ & may ev5 be melt$4 ,build+s are wir$ to use c]ta9 curr5ts1 & if f any cause mu* m curr5t ?an ! regul> am\nt %\ld sudd5ly pass ?r\gh ! s]vice wires into ! h\se1 ! v>i\s small] wires w\ld become ov]heat$1 & p]haps melt or />t a fire4 ,an accid5tal %ort circuit1 = example1 w\ld s r$uce resi/ance t too mu* curr5t w\ld sudd5ly ru% ?r\gh ! wires4 ,!re are sev]al devices by :i* ! ov]-heat+ ( wires is obviat$4 ,illu/ration3 ,figs4 #aga to #age4 ,fig4 #afe %[s a safety fuse1 or safety cut-out1 :i* consi/s ( a %ort l5g? ( easily fusible wire1 call$ fuse wire1 plac$ 9 ! circuit & support$ by a porcela9 block4 ,^! wires are te/$1 diff]5t sizes be+ us$ = diff]5t curr5ts4 ,z soon z !re is any t5d5cy t[>d ov]-heat+1 ! fuse bl[s2 t is1 x promptly melts & op5s ! circuit be=e any damage c be done to ! regul> conductors4 ,fig4 #aff %[s a cross-section ( a fuse plug t c be screw$ into an ord9>y socket4 ,! fuse wire is %[n black4 ,fig4 #afg %[s a fuse l9k4 ,^! are also ( fusible mat]ial1 & s made t !y c be firmly held "u screw-heads4 ,= heavy curr5ts fuse ribbons are us$1 or sev]al wires or l9ks may be us$ side by side4 ,fig4 #afh %[s a fusible rosette4 ,fig4 #afi %[s two fuse wires fix$ betwe5 screw-heads1 ! curr5t pass+ ?r\gh !m 9 opposite directions1 bo? sides ( ! circuit be+ includ$4 ,fig4 #agj %[s v>i\s =ms ( cut-outs4 ,illu/ration3 ,fig4 #agf4 #adc4 ,wires & ,cables are made 9 _m sizes4 ,figs4 #aga to #age %[ v>i\s ways ( mak+ small conductors4 ,!y are made v flexible1 = "s purposes1 by twi/+ _m small copp] wires toge!r1 ! :ole be+ !n cov]$ ) insulat+ mat]ial4 ,illu/ration3 ,fig4 #agg4 ,figs4 #agf1 #agg1 %[ sections ( subm>9e cables4 ,su* cables consi/ ( copp] conductors insulat$ ) pure gutta-p]*a4 ,^! are !n surr\nd$ by hemp5 y>n or o!r ela/ic mat]ial1 & ar\nd ! :ole are plac$ galvaniz$ iron armor wires = protection4 ,ea* core1 or conductor1 conta9s a conductor consi/+ ( a s+le copp] wire or a /r& ( ?ree or m twi/$ copp] wires4 #add4 ,lamp ,circuits4 ,z has be5 not$ be=e1 9 ord] to h ! electric curr5t d its "w1 we mu/ h a complete circuit4 ,! curr5t mu/ be br\ght back to ! dynamo1 mu* ( x1 ( c\rse1 hav+ be5 us$ to produce light1 heat1 p[]1 etc4 ,= light+ purposes ?is is accompli%$ 9 two pr9cipal ways4 ,illu/ration3 ,fig4 #agh4 ,fig4 #agh %[s a numb] ( lamps s arrang$1 9 s]ies1 t ! same curr5t passes ?r\gh !m all1 "o aft] ! o!r4 ,! total resi/ance ( ! circuit is l>ge1 z all ( ! lamp resi/ances are add$ toge!r4 ,illu/ration3 ,fig4 #agi4 ,fig4 #agi %[s lamps arrang$ side by side1 or 9 p>allel1 betwe5 ! two ma9 wires4 ,! curr5t divides1 a "p go+ ?r\gh ea* lamp t op]ates4 ,! total resi/ance ( ! circuit is n z l>ge z 9 ! s]ies arrangem5t1 z ! curr5t has _m small pa?s 9 go+ f "o ma9 wire to ! o!r4 ,fig4 #agi also %[s ! ord9>y two-wire sy/em = inc&esc5t light+1 ! two ma9 wires hav+ usually a diff]5ce ( pot5tial equal to #ej or #aaj volts4 ,^! comp>atively small pressures require fairly l>ge conductors4 ,! ,?ree-,wire ,sy/em1 ,fig4 #ahj1 uses ! curr5t f two dynamos1 arrang$ ) ?ree ma9 wires4 ,:ile ! total voltage is #bbj1 "o ( ! wires be+ neutral1 #aaj volts c be _h = ord9>y lamps4 ,?is voltage saves 9 ! co/ ( conductors4 ,illu/ration3 ,fig4 #ahj4 ,illu/ration3 ,fig4 #aha4 ,! ,alt]nat+ ,sy/em1 ,fig4 #aha1 uses trans=m]s4 ,! high pot5tial ( ! curr5t all[s small ma9 wires1 f :i* bran*es c be run to ! prim>y coil ( ! trans=m]4 ,! second>y coil s5ds out an induc$ curr5t ( #ej or #aaj volts1 :ile t 9 ! prim>y may be #a1jjj to #aj1jjj volts4 ,,*apt] ,,xx4 ,,h[ ,,heat ,,is ,,produc$ ,,by ,,! ,,electric ,,curr5t4 #ade4 ,resi/ance & ,heat4 ,we h se5 t all wires & conductors (f] resi/ance to ! electric curr5t4 ,! small] ! wire ! great] its resi/ance4 ,:5ev] resi/ance is (f]$ to ! curr5t1 heat is produc$4 ,by prop] appliances1 ! heat ( resi/ance c be us$ to advantage = _m comm]cial ent]prises4 ,dynamos are us$ to g5]ate ! curr5t = heat+ & light+ purposes4 ,illu/ration3 ,fig4 #ahb4 ,fig4 #ahb %[s h[ ! curr5t f two /rong cells c be us$ to heat a %ort l5g? ( v f9e plat9um or ,g]man-silv] wire4 ,! copp] conductors atta*$ to ! cells d n (f] v mu* resi/ance4 ,x w be se5 f ! above t 9 all electrical "w ! sizes ( ! wires us$ h to be su* t !y d n ov]heat4 ,! coils ( dynamos1 motors1 trans=m]s1 amp]e-met]s1 etc41 etc41 become some:at heat$ by ! curr5ts pass+ ?r\gh !m1 great c>e be+ tak5 t !y are prop]ly design$ & v5tilat$ s t !y w n burn out4 ,illu/ration3 ,fig4 #ahc4 ,illu/ration3 ,fig4 #ahd4 #adf4 ,electric ,weld+4 ,fig4 #ahc %[s "o =m ( electric weld+ ma*9e4 ,! pr9ciple involv$ 9 ! art ( electric weld+ is t ( caus+ curr5ts ( electricity to pass ?r\gh ! abutt+ ends ( ! pieces ( metal :i* are to be weld$1 !reby g5]at+ heat at ! po9t ( contact1 :i* also becomes ! po9t ( greate/ resi/ance1 :ile at ! same "t me*anical pressure is appli$ to =ce ! p>ts toge!r4 ,z ! curr5t heats ! metal at ! junction to ! weld+ temp]ature1 ! pressure foll[s up ! s(t5+ surface until a complete union or weld is effect$2 &1 z ! heat is fir/ develop$ 9 ! int]ior ( ! p>ts to be weld$1 ! int]ior ( ! jo9t is z effici5tly unit$ z ! visible ext]ior4 ,) su* a me?od & app>atus1 x is f\nd possible to accompli% n only ! common k9ds ( weld+ ( iron & /eel1 b also ( metals :i* h h]et(ore resi/$ attempts at weld+1 & h _h to be braz$ or sold]$4 ,illu/ration3 ,figs4 #ahe to #ahi4 ,! introduction ( ! electric trans=m] enables enorm\s curr5ts to be s appli$ to ! weld z to sp5d _! en]gy j at ! po9t :]e heat+ is requir$4 ,!y ne$1 !re=e1 only to be appli$ = a few seconds1 & ! op]ation is complet$ be=e ! heat g5]at$ at ! weld has _h "t to escape by conduction to any o!r "p4 ,al?\gh ! quantity ( ! curr5t s employ$ 9 ! pieces to be weld$ is enorm\s1 ! pot5tial at :i* x is appli$ is extremely l[1 n mu* exce$+ t ( ! batt]ies ( cells us$ = r++ electric bells 9 h\ses4 ,illu/ration3 ,fig4 #aij4 #adg4 ,miscellane\s ,applications4 ,magneto ,bla/+ ,ma*9es are n[ 9 v common use = bla/+ rocks1 etc4 ,fig4 #ahd %[s "o1 x be+ really a small h& dynamo1 occupy+ less ?an "o-half a cubic foot ( space4 ,! armature is made to revolve rapidly betwe5 ! poles ( ! field-magnet by means ( a h&le t works up & d[n4 ,! curr5t is c>ri$ by wires f ! b9d+-po/s to fuses4 ,! heat g5]at$ by resi/ance 9 ! fuse ignites ! p[d] or o!r explosive4 ,electric sold]+ irons1 flat-irons1 teakettles1 griddles1 broil]s1 glue pots1 *af+-di%es1 /oves1 etc41 etc41 are n[ made4 ,figs4 #ahe to #ahi %[ "s ( ^! applications4 ,! coils = produc+ ! resi/ance are inclos$ 9 ! app>atus4 ,illu/ration3 ,fig4 #aia4 ,fig4 #aij %[s a complete electric kit*54 ,any kettle or "p ( ! outfit c be made hot by simply turn+ a swit*4 ,fig4 #aia %[s an electric heat] plac$ "u a c> seat4 ,_m l>ge indu/ries t make use ( ! heat+ effects ( ! curr5t are n[ be+ c>ri$ on4 ,,*apt] ,,xxi4 ,,h[ ,,light ,,is ,,produc$ ,,by ,,! ,,inc&esc5t ,,lamp4 ,illu/ration3 ,fig4 #aib4 ,illu/ration3 ,fig4 #aic4 #adh4 ,inc&esc5ce4 ,we h j se5 t ! electric curr5t produces heat :5 x fl[s ?r\gh a conductor t (f]s consid]able resi/ance to x4 ,z soon z ?is 0 discov]$ m5 began to exp]im5t to f9d :e!r a practical light c\ld also be produc$4 ,x 0 f\nd t a wire c\ld be kept hot by con/antly pass+ a curr5t ?r\gh x1 & t ! light giv5 out f x became :it] & :it] z ! wire became hott]4 ,! wire 0 said to be inc&esc5t1 or gl[+ ) heat4 ,z metal wires are good conductors ( electricity1 !y _h to be made extremely f9e to (f] en\gh resi/ance2 too f9e1 9 fact1 to be prop]ly h&l$4 #adi4 ,! ,inc&esc5t ,lamp4 ,_m sub/ances 7 exp]im5t$ ^u to f9d a prop] mat]ial out ( :i* c\ld be made a filam5t t w\ld give ! prop] resi/ance & at ! same "t be /rong & la/+4 ,x 0 f\nd t hair-l pieces ( c>bon (f]$ ! prop] resi/ance to ! curr5t4 ,:5 heat$ 9 ! air1 h[ev]1 c>bon burns2 s x became necess>y to place ! c>bon filam5ts 9 a globe f :i* all ! air _h be5 pump$ be=e pass+ ! curr5t ?r\gh !m4 ,?is prov$ to be a success4 ,illu/ration3 ,fig4 #aid4 ,illu/ration3 ,fig4 #aie4 ,illu/ration3 ,fig4 #aif4 ,fig4 #aib %[s ! ord9>y =m ( lamp4 ,! c>bon filam5t is atta*$1 by c>bon pa/e1 to %ort plat9um wires t are seal$ 9 ! glass1 _! l[] ends be+ connect$ to %ort copp] wires t are jo9$ to ! t]m9als ( ! lamp4 ,:5 ! lamp is screw$ into its socket1 ! curr5t c pass up "o side ( ! filam5t & d[n ! o!r4 ,! filam5ts us$ h be5 made ( e =m ( c>boniz$ vegetable matt]4 ,bamboo has be5 l>gely us$1 f9e /rips be+ cut by dies & !n heat$ 9 air-tight boxes conta9+ f9e c>bon until !y 7 ?or\ghly c>boniz$4 ,?is bak+ ( ! bamboo produces a t\gh fib] ( c>bon4 ,v>i\s =ms ( ?read h be5 c>boniz$ & us$4 ,filam5ts are n[ made by press+ f9ely pulv]iz$ c>bon1 ) a b9d+ mat]ial1 ?r\gh small dies4 ,! filam5ts are made ( su* sizes & l5g?s t w adapt !m to ! p>ticul> curr5t ) :i* !y are to be us$4 ,! long] ! filam5t1 ! great] its resi/ance1 & ! great] ! voltage necess>y to pu% ! curr5t ?r\gh x4 ,illu/ration3 ,fig4 #aig4 ,illu/ration3 ,fig4 #aih4 ,aft] ! filam5ts are prop]ly atta*$1 ! air is pump$ f ! bulb or globe4 ,?is is done ) "s =m ( m]cury pump1 & ! air is s ?or\ghly remov$ f ! bulb t ab\t "o-million? only ( ! orig9al air rema9s4 ,be=e seal+ (f ! lamp1 a curr5t is pass$ ?r\gh ! filam5t to drive out absorb$ air & gases1 & ^! are c>ri$ away by ! pump4 ,by prop] treatm5t ! filam5ts h a uni=m resi/ance ?r\gh\t1 & gl[ uni=mly :5 ! curr5t passes4 ,illu/ration3 ,fig4 #aii4 ,illu/ration3 ,fig4 #bjj4 #aej4 ,c&le-,p[]4 ,a lamp is said to h #d1 #h1 #af or m c&le-p[]4 ,a #af-;c&le-p[] lamp1 = example1 means "o t w give z mu* light z sixte5 /&>d c&les4 ,a /&>d sp]m c&le burns two gra9s a m9ute4 ,! c&le-p[] ( a lamp c be increas$ by =c+ a /rong curr5t ?r\gh x1 b ?is %ort5s its life4 ,! ,curr5t us$ = inc&esc5t lamps has to be /rong en\gh to =ce its way ?r\gh ! filam5t & produce a heat suffici5t to give a good light4 ,! usual curr5t has #ej or #aaj volts1 al?\gh small lamps are made t c be run by two or ?ree cells4 ,if ! voltage ( ! curr5t is less ?an t = :i* ! lamp 0 made1 ! light w be dim4 ,! filam5t c be in/antly burn$ out by pass+ a curr5t ( too high pressure ?r\gh x4 ,ev5 ) ! prop] curr5t1 lamps soon beg9 to det]iorate1 z small p>ticles ( c>bon leave ! filam5t & cl+ to ! glass4 ,?is is due to ! evaporation1 & x makes ! filam5t small]1 & a high] pressure is !n ne$$ to =ce ! curr5t ?r\gh ! increas$ resi/ance2 besides ?is1 ! d>k5$ bulb does n prop]ly let ! light out4 ,! curr5t may be direct or alt]nat+4 ,illu/ration3 ,fig4 #bja4 ,illu/ration3 ,fig4 #bjb4 #aea4 ,! ,uses to :i* inc&esc5t lamps are put are almo/ numb]less4 ,fig4 #aic %[s a decorative lamp4 ,fancy lamps are made 9 all colors4 ,fig4 #aid %[s a conic c&le lamp1 to imitate a c&le4 ,:at corresponds to ! body ( ! c&le 7see figure ,b to ,c7 is a delicately t9t$ opal glass tube surm\nt$ 7see figure ,a to ,b7 by a f9ely proportion$ conic lamp ) fro/$ globe4 ,c to ,d 9 ! figure repres5ts ! regul> base1 & ?us ! relative proportions ( ! p>ts are %[n4 ,fig4 #aie %[s ano!r =m ( c&elabra lamp4 ,fig4 #aif %[s small d5tal lamps4 ,fig4 #aig %[s a small lamp ) mirror = use 9 ! ?roat4 ,fig4 #aih %[s lamp ) half %ade atta*$1 us$ = libr>y tables4 ,fig4 #aii %[s an electric p5dant = sev]al lamps1 ) %ade4 ,fig4 #bjj %[s a lamp gu>d4 ,fig4 #bja %[s a lamp socket1 into :i* ! lamp is screw$4 ,fig4 #bjb %[s inc&esc5t bulbs jo9$ 9 p>allel to ! & - ma9s4 ,fig4 #bjc %[s h[ ! lamp cord c be adju/$ to desir$ l5g?4 ,fig4 #bjd %[s a lamp ) reflector plac$ on a desk4 ,fig4 #bje %[s a =m ( %ade & reflector4 ,illu/ration3 ,fig4 #bjc4 ,illu/ration3 ,fig4 #bjd4 ,illu/ration3 ,fig4 #bje4 ,,*apt] ,,xxii4 ,,h[ ,,light ,,is ,,produc$ ,,by ,,! ,,arc ,,lamp4 #aeb4 ,! ,electric ,arc4 ,:5 a /rong curr5t passes f "o c>bon rod to ano!r across an air-space1 an electric arc is produc$4 ,:5 ! ends ( two c>bon rods t\*1 a curr5t c pass f "o to ! o!r1 b ! imp]fect contact causes resi/ance en\gh to heat ! ends r$-hot4 ,if ! rods be sep>at$ slightly1 ! curr5t w cont9ue to fl[1 z ! int5sely heat$ air & fly+ p>ticles ( c>bon r$uce ! resi/ance ( ! air-space4 ,fig4 #bjf %[s two c>bon rods :i* are jo9$ to ! two t]m9als ( a dynamo4 ,! upp]1 or positive1 c>bon gradually we>s away & becomes slightly holl[4 ,! heat$ crat]1 z x is call$1 is ! hotte/ "p4 ,! negative c>bon becomes po9t$4 ,! arc w pass 9 a vacuum1 & ev5 "u wat]4 ,illu/ration3 ,fig4 #bjf4 ,z ! electric arc is extremely hot1 metals are easily vaporiz$ 9 x2 9 fact1 ev5 ! c>bon rods !mselves sl[ly melt & vaporize4 ,?is extreme heat is us$ = _m indu/rial purposes4 ,illu/ration3 ,fig4 #bjg4 ,illu/ration3 ,fig4 #bjh4 ,! ph5om5on ( ! electric arc 0 fir/ notic$ by ,humphrey ,davy 9 #ahjj1 & its explanation appe>s to be ! foll[+3 ,be=e contact ! diff]5ce ( pot5tial betwe5 ! po9ts is insuffici5t to p]mit a sp>k to leap across ev5 #a_/ajjjj ( an in* ( air-space1 b :5 ! c>bons are made to t\*1 a curr5t is e/abli%$4 ,on sep>at+ ! c>bons1 ! mom5t>y extra curr5t due to self-induction ( ! circuit1 :i* possesses a high electromotive =ce1 c leap ! %ort di/ance1 & 9 do+ s volatilizes a small quantity ( c>bon betwe5 ! po9ts4 ,c>bon vapor1 be+ a p>tial conductor1 all[s ! curr5t to cont9ue to fl[ across ! gap1 provid$ x be n too wide2 b z ! c>bon vapor has a v high resi/ance x becomes int5sely heat$ by ! passage ( ! curr5t1 & ! c>bon po9ts also gr[ hot4 ,s9ce1 h[ev]1 solid matt] is a bett] radiator ?an gase\s matt]1 ! c>bon po9ts emit f> m light ?an ! arc itself1 ?\gh !y are n s hot4 ,x is obs]v$1 also1 t p>ticles ( c>bon are torn away f ! electrode1 :i* becomes holl[$ out to a cup-%ape1 & "s ( ^! are deposit$ on ! - electrode4 ,illu/ration3 ,fig4 #bji4 #aec4 ,arc ,lamps4 ,z ! c>bons gradually we> away1 "s device is necess>y to keep _! ends ! "r di/ance ap>t4 ,if !y are too ne>1 ! arc is v small2 & if too f> ap>t1 ! curr5t c n pass & ! light goes out4 ,! positive c>bon gives ! m int5se light & we>s away ab\t twice z fa/ z ! - c>bon1 s x is plac$ above ! - c>bon1 to ?r[ ! light d[nw>ds4 ,illu/ration3 ,fig4 #baj4 ,illu/ration3 ,fig4 #baa4 ,arc lamps conta9 "s device by :i* ! prop] di/ance betwe5 ! c>bons c be kept4 ,mo/ ( !m grip ! upp] c>bon & pull x f> en\gh above ! l[] "o to e/abli% ! arc4 ,z soon z ! di/ance betwe5 !m gets too great aga91 ! grip on ! upp] c>bon is loos5$1 all[+ ! c>bon to drop until x comes 9 contact ) ! l[] "o1 ?us />t+ ! curr5t aga94 ,^! motions are accompli%$ by electromagnets4 ,fig4 #bjg %[s a =m ( arc lamp ) s+le c>bons t w burn f #g to #i h\rs4 ,illu/ration3 ,fig4 #bab4 ,illu/ration3 ,fig4 #bac4 ,illu/ration3 ,fig4 #bad4 ,fig4 #bjh %[s ! me*anism by :i* ! c>bons are regulat$4 ,fig4 #bji %[s a =m ( d\ble c>bon1 or all-night lamp1 "o set ( c>bons be+ fir/ us$1 ! o!r set be+ automatically swit*$ 9 at ! prop] "t4 ,illu/ration3 ,fig4 #bae4 ,figs4 #baj1 #baa %[ =ms ( %ort arc lamps1 = use "u l[ ceil+s1 s common 9 basem5ts1 etc4 ,fig4 #bab %[s a h&-fe$ focuss+ type ( arc lamp4 ,9 regul> /reet lamps1 ! upp] c>bon only is f$ by me*anism1 z x burns away ab\t twice z fa/ z ! l[] "o1 ?us br++ ! arc l[] & l[]4 ,:5 x is desir$ to keep ! arc at ! focus ( a reflector1 bo? c>bons mu/ be f$4 ,fig4 #bac %[s a !atre arc lamp1 us$ to ?r[ a /rong beam ( light f ! balcony to ! /age4 ,fig4 #bad %[s ! arc lamp us$ z a se>*-light4 ,! reflector ?r[s a p[]ful beam ( light t c be se5 = miles2 9 fact1 ! light is us$ = signall+ at night4 ,fig4 #bae %[s h[ se>*-lights are us$ at night on w>-vessels4 ,,*apt] ,,xxiii4 ,x-,,rays1 ,,& ,,h[ ,,! ,,bones ,,( ,,! ,,human ,,body ,,are ,,photograph$4 ,illu/ration3 ,fig4 #baf4 ,illu/ration3 ,fig4 #bag4 #aed4 ,disruptive ,dis*>ges4 ,we h se51 9 ! /udy ( induction coils1 t a sp>k c jump sev]al in*es betwe5 ! t]m9als ( ! second>y coil4 ,! attraction betwe5 ! two oppositely *>g$ t]m9als gets s great t x ov]comes ! resi/ance ( ! air-space betwe5 !m1 a brilliant sp>k passes1 & !y are dis*>g$4 ,?is sudd5 dis*>ge is said to be disruptive1 & x is accompani$ by a fla% ( light & a l\d report4 ,! pa? ( ! dis*>ge may be ne>ly /raight1 or crook$1 dep5d+ ^u ! nature ( ! mat]ial 9 ! gap betwe5 ! t]m9als4 ,illu/ration3 ,fig4 #bah4 ,illu/ration3 ,fig4 #bai4 #aee4 ,effect ( ,air ,pressure on ,sp>k4 ,! disruptive sp>k takes place 9 air at ord9>y pressures4 ,! nature ( ! sp>k is greatly *ang$ :5 ! pressure ( ! air decreases4 ,fig4 #baf %[s an air-tight glass tube s arrang$ t ! air c be sl[ly remov$ ) an air-pump4 ,! upp] rod %[n c be rais$ or l[]$ to increase ! di/ance betwe5 x & ! l[] rod1 ^! act+ z ! t]m9als ( an induction coil4 ,be=e exhau/+ any air1 ! sp>k w jump a small di/ance betwe5 ! rods & act z 9 op5 air4 ,z soon z a small am\nt ( air is remov$1 a *ange takes place4 ,! sp>k is n s int5se & has no def9ite pa?1 !re be+ a g5]al gl[ ?r\gh\t ! tube4 ,z ! air pressure becomes /ill less1 ! gl[ becomes bright]1 until ! entire tube is full ( purple light t is able to pass ! entire l5g? ( x2 t is1 ! dis*>ge takes place bett] 9 r>efi$ air ?an x does 9 ord9>y air4 #aef4 ,vacuum-,tubes4 ,z electricity passes ?r\gh r>efi$ gases mu* easi] ?an ?r\gh ord9>y air1 regul> tubes1 call$ vacuum-tubes1 are made = su* /udy4 ,fig4 #bag %[s a pla9 tube ( ?is k9d1 plat9um t]m9als be+ fus$ 9 ! glass = connections4 ,^! tubes are (t5 made 9 complicat$ =ms1 ,fig4 #bah1 ) color$ glass1 & are call$ ,geissl] tubes4 ,!y are (t5 made 9 su* a way t ! electrodes are 9 ! %ape ( discs1 etc41 & are call$ ,crookes tubes1 ,fig4 #bai4 ,a slight am\nt ( gas is left 9 ! tubes4 ,illu/ration3 ,fig4 #bbj4 ,illu/ration3 ,fig4 #bbj-;,a4 #aeg4 ,ca?ode ,rays4 ,! ca?ode is ! electrode ( a vacuum-tube by :i* ! curr5t leaves ! tube1 & x has be5 kn[n = "s "t t "s k9d ( influ5ce passes 9 /raight l9es f ?is po9t4 ,%ad[s1 ,fig4 #bai1 are ca/ by su* rays1 a scre5 be+ plac$ 9 _! pa?4 #aeh4 ,x-,rays4 ,pr(essor ,ro5tg5 ( ,wrzburg discov]$ t :5 ! ca?ode rays are all[$ to fall ^u a solid body1 ! solid body gives out /ill o!r rays :i* diff] some:at f ! orig9al ca?ode rays4 ,!y c p5etrate1 m or less1 ?r\gh _m bodies t are usually consid]$ opaque4 ,! h&1 = example1 may be us$ z a negative = produc+ a photograph ( ! bones1 z ! rays d n pass equally well ?r\gh fle% & bone4 ,illu/ration3 ,fig4 #bba4 ,fig4 #bbj %[s a ,crookes tube fitt$ ) a metal plate1 s t ! ca?ode rays com+ f ,c w /rike x4 ,! ,x-rays are giv5 out f ,p4 ,^! rays are invisible & are ev5 giv5 out :]e ! ca?ode rays /rike ! glass4 ,"s *emical comp\nds are made lum9\s by ^! rays2 s scre5s are made & coat$ ) !m 9 ord] t ! %ad[s produc$ by ! ,x-rays c be se5 by ! eye4 ,pr(essor ,ro5tg5 nam$ ^! ! ,x-rays4 ,fig4 #bbj-;,a %[s a fluoroscope t conta9s a scre5 cov]$ ) prop] *emicals4 ,illu/ration3 ,fig4 #bbb4 ,illu/ration3 ,fig4 #bbc4 #aei4 ,x-,ray ,photographs4 ,bone does n all[ ! ,x-rays to pass ?r\gh x z readily z fle%1 s if ! h& be plac$ ov] a s5sitiz$ photographic plate1 ,fig4 #bba1 & prop] connections be made ) ! induction coil1 etc41 ! h& acts z a photographic negative4 ,^u develop+ ! plate1 z 9 ord9>y photography1 a picture or %ad[ ( ! bones w be se54 ,fig4 #bbb %[s ! arrangem5t ( batt]y1 induction coil1 focus tube1 etc41 = exam9+ ! bones ( ! human body4 ,fig4 #bbc %[s ! bones ( a fi%4 ,su* photographs h be5 v valuable 9 discov]+ ! location ( bullets1 ne$les1 etc41 t h become imb$d$ 9 ! fle%1 z well z 9 locat+ breaks 9 ! bones4 ,,*apt] ,,xxiv4 ,,! ,,electric ,,motor1 ,,& ,,h[ ,,x ,,does ,,"w4 #afj4 ,curr5ts & ,motion4 ,we h se51 ,*apt] ,,xii41 t :5 coils ( wire are rapidly mov$ across a /rong magnetic field1 a curr5t ( electricity is g5]at$4 ,we h n[ to deal ) ! opposite ( ?is2 t is1 we are to /udy h[ motion c be produc$ by all[+ a curr5t ( electricity to pass ?r\gh ! armature ( a ma*9e4 ,illu/ration3 ,fig4 #bbd4 ,illu/ration3 ,fig4 #bbe4 ,fig4 #bbd %[s1 by diagram1 a coil ,h1 susp5d$ s t x c move easily1 its ends be+ jo9$ to a curr5t rev]s]1 & ?is1 9 turn1 to a dry cell ,d ,c4 ,a magnet1 ,h ,m1 w attract ! core ( ,h :5 no curr5t passes4 ,:5 ! curr5t is all[$ to pass fir/ 9 "o direction & !n 9 ! opposite direction1 by us+ ! rev]s]1 ! core ( ,h w jump back & =? f "o pole ( ,h ,m to ! o!r4 ,!re are _m ways by :i* motion c be produc$ by ! curr5t1 b to h x practical1 ! motion mu/ be a rot>y "o4 7,see ,/udy1 ,*apt] ,,xxvi41 = num]\s exp]im5ts47 ,illu/ration3 ,fig4 #bbf4 #afa4 ,! ,electric ,motor is a ma*9e = trans=m+ electric en]gy into me*anical p[]4 ,! con/ruction ( motors is v simil> to t ( dynamos4 ,!y h field-magnets1 armature coils1 commutator1 etc42 9 fact1 ! armature ( an ord9>y direct curr5t dynamo w revolve if a curr5t be pass$ ?r\gh x1 ent]+ by "o bru% & leav+ by ! o!r4 ,!re are _m little diff]5ces ( con/ruction1 = me*anical & electrical reasons1 b we may say t ! g5]al con/ruction ( dynamos & motors is ! same4 ,fig4 #bbe %[s a coil ( wire1 ! ends ( :i* are connect$ to copp] & z9c plates4 ,^! plates are float$ 9 dilute sulphuric acid1 & =m a simple cell :i* s5ds a curr5t ?r\gh ! wire1 z %[n by ! arr[s4 ,illu/ration3 ,fig4 #bbg4 ,we h se5 t a curr5t-c>ry+ wire has a magnetic field & acts l a magnet2 s x w be easily se5 t if a magnet be held ne> ! wire x w be ei!r attract$ or repell$1 ! motion dep5d+ ^u ! poles t come ne> ea* o!r4 ,z %[n 9 ! figure1 ! ,n pole ( ! magnet repels ! field ( ! wire1 caus+ x to revolve4 ,we see t ?is action is j ! rev]se to t 9 galvanomet]s1 :]e ! coil is fix$1 & ! magnet1 or magnetic ne$le1 is all[$ to move4 ,z soon z ! "p ( ! wire1 m>k$ ,a 9 ,fig4 #bbe1 gets a little di/ance f ! pole1 ! opposite side ( ! wire1 ,b1 beg9s to be attract$ by x1 ! attraction gett+ /rong] & /rong]1 until x gets opposite ! ,n pole4 ,if ! ,n pole 7 /ill held 9 place1 ,b w\ld vibrate back & =? a few times1 & f9ally come to re/ ne> ! pole4 ,if1 h[ev]1 z soon z ,b gets opposite ,n ! ,s pole ( ! magnet be quickly turn$ t[>d ,b1 ! coil w be repell$ & ! rot>y motion w cont9ue4 ,illu/ration3 ,fig4 #bbh4 ,illu/ration3 ,figs4 #bbi to #bca4 ,illu/ration3 ,fig4 #bcb4 ,illu/ration3 ,fig4 #bcc4 ,let u n[ see h[ ?is helps to expla9 electric motors4 ,we may consid] ! wire ( ,fig4 #bbe z "o coil ( an armature1 & ! plates1 ,c & ,z1 z ! halves ( a commutator4 ,9 ?is arrangem5t1 x mu/ be not$1 ! curr5t always fl[s ?r\gh ! armature coil 9 ! same direction1 ! rotation be+ kept up by rev]s+ ! poles ( ! field-magnet4 ,9 ord9>y simple motors ! curr5t is rev]s$ 9 ! armature coils1 ! field-magnets rema9+ 9 "o position )\t *ang+ ! poles4 ,?is produces ! same effect z ! above4 ,! curr5t is rev]s$ automatically z ! bru%es all[ ! curr5t to ent] fir/ "o commutator b> & !n ! opposite "o z ! armature revolves4 ,! regul> armatures h _m coils & _m commutator b>s1 z w be se5 by exam9+ ! illu/rations %[n4 ,! ord9>y galvanomet] may be consid]$ a =m ( motor4 ,by prop]ly op5+ & clos+ ! circuit1 ! rot>y motion ( ! ne$le c be kept up z long z curr5t is suppli$4 ,ev5 an electric bell or telegraph s\nd] may be consid]$ a motor1 giv+ motion /raight =w>d & back4 #afb4 ,! ,uses ( ,motors are _m4 ,x w\ld be impossible to m5tion all ! ?+s t are done ) ! p[] f motors4 ,a few illu/rations w give an idea ( ! way motors are atta*$ to ma*9es4 ,fig4 #bbf %[s "o =m ( motor1 ! p>ts be+ %[n 9 ,fig4 #bbg4 ,illu/ration3 ,fig4 #bcd4 ,fig4 #bbh %[s a fan motor run by a batt]y4 ,!y are g5]ally run by ! curr5t f ! /reet4 ,figs4 #bbi-bca %[ o!r =ms ( fan motors4 ,fig4 #bcb %[s an electric hat poli%]4 ,a *ur* organ bell[s is %[n 9 ,fig4 #bcc1 s arrang$ t x c be pump$ by an electric motor4 ,fig4 #bcd %[s a motor direct connect$ to a drill press4 #afc4 ,/>t+ ,boxes4 ,if too mu* curr5t 7 sudd5ly all[$ to pass into ! armature ( a motor1 ! coils w\ld be ov]-heat$1 & p]haps de/roy$1 be=e x atta9$ its full spe$4 ,a rapidly revolv+ armature w take m curr5t1 )\t be+ ov]heat$1 ?an "o n 9 motion4 ,a motor at full spe$ acts l a dynamo1 & g5]ates a curr5t :i* t5ds to fl[ f ! ma*9e 9 a direction opposite to t :i* produces ! motion4 ,x is evid5t1 !n1 t :5 ! armature is at re/1 all ! curr5t turn$ on passes ?r\gh x )\t meet+ ) ?is oppos+ curr5t4 ,illu/ration3 ,fig4 #bce4 ,illu/ration3 ,fig4 #bcf4 ,fig4 #bce %[s a />t+1 /opp+1 & regulat+ box1 inside ( :i* are a numb] ( ,g]man-silv] resi/ance coils prop]ly connect$ to contact-po9ts at ! top4 ,by turn+ ! knob1 ! field ( ! motor is imm$iately *>g$ fir/ ?r\gh resi/ance1 !n direct1 & !n ! curr5t is put on ! armature gradually ?r\gh a s]ies ( coils1 ! am\nt ( curr5t dep5d+ ^u ! di/ance ! swit* is turn$4 ,fig4 #bcf %[s a cross section ( ! same4 ,,*apt] ,,xxv4 ,,electric ,,c>s1 ,,boats1 ,,& ,,automobiles4 #afd4 ,electric ,c>s1 z well z boats1 automobiles1 etc41 etc41 are mov$ by ! p[] t comes f electric motors1 ^! receiv+ curr5t f ! dynamos plac$ at "s c5tral /ation4 ,we h already se5 h[ ! motor c d _m k9ds ( "w4 ,by prop]ly ge>+ x to ! c> :eels1 motion c be giv5 to !m :i* w move ! c>4 ,illu/ration3 ,fig4 #bcg4 ,fig4 #bcg %[s two dynamos :i* w be suppos$ to be at a p[] h\se & :i* s5d out a curr5t to propel c>s4 ,f ! figure x w be se5 t ! wires ov] ! c>s1 call$ trolley-wires1 are connect$ to ! positive 77 t]m9als ( ! dynamos1 & t ! negative 7-7 t]m9als are connect$ to ! tracks4 ,9 case a wire 7 all[$ to jo9 ! trolley-wire & track1 we %\ld h a %ort circuit1 & curr5t w\ld n only ru% back to ! dynamo )\t do+ useful "w1 b x w\ld probably injure ! ma*9es4 ,:5 "s ( ! curr5t is all[$ to pass ?r\gh a c>1 motion is produc$ 9 ! motors1 z has be5 expla9$4 ,z ! numb] ( c>s increases1 m curr5t passes back to ! dynamos1 :i* mu/ d m "w to furni% su* curr5t4 ,trolley-poles1 fa/5$ to ! top ( ! c>s & :i* end 9 groov$ :eels1 call$ trolley-:eels1 are press$ by spr+s aga9/ ! trolley-wires4 ,! curr5t passes d[n ^! ?r\gh swit*es to controll]s at ea* end ( ! c>1 "o set be+ us$ at a "t4 ,illu/ration3 ,fig4 #bch4 ,illu/ration3 ,fig4 #bci4 #afe4 ,! ,controll]s1 z ! "n sugge/s1 control ! spe$ ( ! c> by all[+ m or less curr5t to pass ?r\gh ! motors4 ,! motors1 resi/ance coils & controll]s are s connect$ ) ea* o!r t ! am\nt ( curr5t us$ c be regulat$4 ,illu/ration3 ,fig4 #bdj4 ,illu/ration3 ,fig4 #bda4 ,:5 ! motorman turns ! h&le ( ! controll] to ! fir/ not*1 ! curr5t passes ?r\gh all ( ! resi/ance wires plac$ "u ! c>1 !n ?r\gh "o motor aft] ! o!r4 ,! motors be+ jo9$ 9 s]ies by ! prop] connections at ! controll]1 ! greate/ resi/ance is (f]$ to ! curr5t & ! c> runs at ! sl[e/ spe$ at ?is fir/ not*4 ,z m resi/ance is cut out by turn+ ! h&le to o!r not*es1 ! c> increases its spe$2 b z ! resi/ance wires become heat$ & ! heat passes into ! air1 !re is a loss ( en]gy4 ,x is n economical to run a c> at su* a spe$ t en]gy is wa/$ z heat4 ,z soon z ! resi/ance is all cut out1 ! curr5t simply passes ?r\gh ! motors jo9$ 9 s]ies4 ,?is gives a fairly sl[ spe$ & "o t is economical because all ! curr5t t5ds to produce motion4 ,by all[+ ! curr5t to pass ?r\gh ! motors jo9$ 9 p>allel1 t is1 by all[+ ea* to take a "p ( ! curr5t1 ! resi/ance is greatly r$uc$1 & a high] spe$ atta9$4 ,?is is n in/antly done1 h[ev]1 z too mu* /ra9 w\ld be put ^u ! motors4 ,z soon z ! next not* is rea*$1 ! motors are jo9$ 9 p>allel & ! resi/ance also ?r[n 9 aga94 ,by turn+ ! h&le /ill m1 resi/ance is gradually cut out1 & ! highe/ spe$ produc$ :5 ! curr5t passes only ?r\gh ! motors 9 p>allel4 ,illu/ration3 ,fig4 #bdb4 ,illu/ration3 ,fig4 #bdc4 ,fig4 #bch repres5ts a controll]1 by diagram1 %[+ ! relative positions ( ! controll] cyl9d]1 rev]s+ & cut-out cyl9d]s1 arrangem5ts = bl[+ out ! %ort electric arcs =m$1 etc4 ,a rat*et & pawl is provid$1 :i* indicates positively ! runn+ not*es1 at ! same "t p]mitt+ ! cyl9d] to move ) ease4 ,fig4 #bci %[s a top view ( ! controll]4 ,illu/ration3 ,fig4 #bdd4 #aff4 ,ov]head & ,und]gr\nd ,sy/ems4 ,:5 wires = furni%+ curr5t are plac$ ov] ! tracks1 z 9 ,fig4 #bcg1 we h ! ov]head sy/em4 ,9 cities ! und]gr\nd sy/em is l>gely us$4 ,! location ( ! conduct+ wires b5ea? ! surface ( ! /reet removes all dang] to ! public1 & protects !m f all int]f]5ce1 leav+ ! /reet free f poles & wires4 ,fig4 #bdj %[s a cross-section ( an und]gr\nd conduit4 ,! rails1 ,r ,r1 are support$ by ca/-iron yokes1 ,a1 plac$ five feet ap>t1 & ?or\ghly imb$d$ 9 concrete4 ,! conduit has sew] connections e #ajj feet4 ,conduct+ b>s1 ,c ,c1 are plac$ on ea* side ( ! conduit1 & ^! are divid$ into sections ( ab\t #ejj feet4 ,insulators1 ,d ,d1 are plac$ e #ae feet4 ,!y are atta*$ to1 & directly "u1 ! slot-rails1 ! /em pass+ ?r\gh ! conductor b>4 ,illu/ration3 ,fig4 #bde4 ,figs4 #bdj & #bda %[ ! pl[ ,e4 ,! contact plates are c>ri$ on coil$ spr+s to all[ a free motion4 ,two guide-:eels1 ,f ,f1 are atta*$ to ! leg ( ! pl[4 ,! conduct+ wires are c>ri$ up ?r\gh ! leg ( ! pl[4 #afg4 ,appliances4 ,a l>ge numb] ( articles are ne$$ 9 ! con/ruction ( electric railroads4 ,a few1 only1 c be %[n t are us$ = ! ov]head sy/em4 ,fig4 #bdb %[s a pole insulator4 ,fig4 #bdc %[s a fe$]-wire insulator4 ,fig4 #bdd %[s a l9e susp5sion4 ,fig4 #bde %[s a =m ( "r-angle cross :i* all[s ! trolley-:eels ( cross+ l9es to pass4 ,fig4 #bdf %[s a swit*4 ,9 w9t] a "p ( ! curr5t is all[$ to pass ?r\gh electric heat]s plac$ "u ! seats ( electric c>s4 ,illu/ration3 ,fig4 #bdf4 #afh4 ,electric ,boats are run by ! curr5t f /orage batt]ies :i* are usually plac$ "u ! seats4 ,an electric motor l>ge en\gh to run a small boat takes up v little room & is g5]ally plac$ "u ! floor4 ,?is leaves ! entire boat = ! use ( pass5g]s4 ,! motor is connect$ to ! %aft t turns ! screw4 ,fig4 #bdg %[s "o design4 #afi4 ,electric ,automobiles repres5t ! highe/ type ( electrical & me*anical con/ruction4 ,! runn+-ge> is usually made ( ! be/ cold-drawn seamless /eel tub+1 to get ! greate/ /r5g? f a giv5 weight ( mat]ial4 ,! :eels are made 9 a v>iety ( /yles1 b ne>ly all h ball be>+s & pneumatic tires4 ,9 ! lighte/ /yles ! :eels h wire spokes4 ,! electric motors1 support$ by ! runn+-ge>1 are ge>$ to ! re> :eels4 ,! motors are made z ne>ly du/-pro( z possible4 ,/orage batt]ies are put 9 a conv5i5t place1 dep5d+ ^u ! design ( ! c>riage1 & f ^! ! motors receive ! curr5t4 ,^! c be *>g$ f ! ord9>y #aaj-volt light+ circuits or f private dynamos4 ,! prop] plugs & atta*m5ts are usually furni%$ by ! v>i\s mak]s = connect+ ! batt]ies ) ! /reet curr5t1 :i* is %ut (f :5 ! batt]ies are full by an automatic swit*4 ,illu/ration3 ,fig4 #bdg4 ,controll]s are us$1 z on electric c>s1 ! lev] = />t+1 /opp+1 etc41 be+ usually plac$ on ! left-h& side ( ! seat4 ,! /e]+ is done by a lev] t moves ! front :eels4 ,/rong brakes1 & ! ability to quickly rev]se ! motors1 all[ electric c>riages to be /opp$ sudd5ly 9 case ( accid5ts4 ,electric automobiles are l>gely us$ 9 cities1 or :]e ! curr5t c be easily _h4 ,! batt]ies mu/ be re-*>g$ aft] !y h run ! motors = a c]ta9 "t :i* dep5ds ^u ! spe$ & road1 z well z ^u ! con/ruction4 ,:]e c>riages are to be run almo/ con/antly1 z is ! case ) ^? us$ = g5]al pass5g] s]vice 9 cities1 duplicate batt]ies are necess>y1 s t "o or two sets c be *>g$ :ile ano!r is 9 use4 ,fig4 #bdh %[s "o =m ( electric vehicle1 ! /orage batt]ies be+ plac$ "u & back ( ! seat4 ,illu/ration3 ,fig4 #bdh4 ,,*apt] ,,xxvi4 ,a ,,^w ,,ab\t ,,c5tral ,,/ations4 #agj4 ,c5tral ,/ations1 z ! ^w implies1 are places :]e1 = example1 electricity is g5]at$ = ! inc&esc5t or arc lights us$ 9 a c]ta9 neighborhood2 :]e telephone or telegraph messages are s5t to be res5t to "s o!r /ation2 :]e op]ators are kept to swit* diff]5t l9es toge!r1 s t ^? on "o l9e c talk to ^? on ano!r1 etc41 etc4 ,!re are _m k9ds ( c5tral /ations1 ea* requir+ a l>ge am\nt ( special app>atus to c>ry on ! "w4 ,fig4 #bdi gives a h9t 9 reg>d to ! way c> l9es get _! p[] f a c5tral p[] /ation4 ,z a l>ge "p ( ! app>atus requir$ 9 ord9>y c5tral /ations has already be5 describ$1 x is n necess>y to g into ! details ( su* /ations4 ,illu/ration3 ,fig4 #bdi4 ,9 light+ /ations1 = example1 we h ?ree pr9cipal k9ds ( app>atus4 ,boil]s produce ! /eam t runs ! /eam eng9es1 & ^! run ! dynamos t give ! curr5t4 ,besides ^! !re are _m o!r ?+s ne$$4 ,! electrical en]gy t goes ov] ! wires to furni% light1 heat1 & p[]1 really comes indirectly f ! coal t is us$ to boil wat] & conv]t x into /eam4 ,! v>i\s p>ts ( ! c5tral /ation m]ely aid 9 ?is trans=mation ( en]gy4 ,illu/ration3 ,fig4 #bej4 ,illu/ration3 ,fig4 #bea4 ,! dynamos are connect$ to ! eng9es by belts1 or !y are direct connect$4 ,figs4 #bej1 #bea1 %[ dynamos connect$ to eng9es )\t belts4 ,! curr5t f ! dynamos is l$ to l>ge swit*bo>ds :i* conta9 swit*es1 voltmet]s1 ammet]s1 lightn+ arre/]s1 & v>i\s o!r app>atus = ! prop] control & measurem5t ( ! curr5t4 ,f ! swit*bo>d x is all[$ to pass ?r\gh ! v>i\s /reet ma9s1 f :i* x is f9ally l$ to lamps1 motors1 etc4 ,wat]-p[] is frequ5tly us$ to drive ! dynamos in/ead ( /eam eng9es4 ,! wat] turns "s =m ( wat]-:eel :i* is connect$ to ! dynamos4 ,at ,niag>a ,falls1 = example1 imm5se quantities ( curr5t are g5]at$ = light1 heat1 p[]1 & indu/rial purposes4 ,illu/ration ,,*apt] ,,xxvii4 ,,miscellane\s ,,uses ,,( ,,electricity4 #aga4 ,! ,_m ,uses to :i* ! electric curr5t is put are almo/ numb]less4 ,new uses are be+ f\nd = x e day4 ,"s ( ! common applications are giv5 bel[4 #agb4 ,automatic ,electric ,program ,clocks1 ,fig4 #beb1 are l>gely us$ 9 all sorts ( e/abli%m5ts1 s*ools1 etc41 = r++ bells at c]ta9 /at$ p]iods4 ,! l[] dial %[n has _m contact-po9ts t c be ins]t$ to correspond to giv5 times4 ,z ?is revolves1 ! circuits are clos$1 "o aft] ! o!r1 & x may be s set t bells w be rung 9 diff]5t p>ts ( ! h\se e five m9utes1 if desir$4 ,illu/ration3 ,fig4 #beb4 ,illu/ration3 ,fig4 #bec4 #agc4 ,call ,boxes are us$ to s5d 9 calls ( v>i\s k9ds to c5tral /ations4 ,fig4 #bec %[s "o =m4 ,! numb] ( diff]5t calls provid$ includes mess5g]1 c>ri]1 c\p1 express wagon1 doctor1 labor]1 police1 fire1 toge!r ) ?ree m1 :i* may be made special to suit ! conv5i5ce ( ! individual cu/om]4 ,! in/rum5ts are provid$ ) app>atus = receiv+ a return signal1 ! object ( :i* is to notify ! subscrib] t 8 call has be5 receiv$ & is hav+ att5tion4 ,illu/ration3 ,fig4 #bed4 ,illu/ration3 ,fig4 #bee4 ,fig4 #bed %[s ano!r =m ( call box1 ! h&le be+ mov$ ar\nd to ! call desir$4 ,z x spr+s back to ! orig9al position1 an int]rupt$ curr5t passes ?r\gh ! box to ! c5tral /ation1 caus+ a bell to tap a c]ta9 numb] ( times1 giv+ ! call & location ( ! box4 #agd4 ,electric ,gas-,light]s4 ,fig4 #bee %[s a rat*et burn]4 ,! fir/ pull ( ! *a9 turns on ! gas ?r\gh a f\r-way gas-cock1 gov]n$ by a rat*et-:eel & pawl4 ,! issu+ gas is light$ by a wipe-sp>k at ! tip ( ! burn]4 ,alt]nate pulls %ut (f ! gas4 ,z ! lev] br+s ! atta*$ wire ,a1 9 contact ) ! wire ,b1 a bright sp>k passes1 :i* ignites ! gas1 ! burn] be+ jo9$ ) a batt]y & induction or sp>k coil4 ,automatic burn]s are us$ :5 x is desir$ to light gas at a di/ance f ! pu%-button4 ,fig4 #bef %[s "o =m4 ,two electromagnets are %[n1 "o be+ g5]ally jo9$ to a :ite pu%-button = turn+ on ! gas & light+ x1 ! o!r be+ jo9$ to a black button :i* turns (f ! gas :5 x is press$4 ,! armatures ( ! magnets "w ! gas-valve4 ,sp>ks ignite ! gas1 z expla9$ above4 ,illu/ration3 ,fig4 #bef4 ,illu/ration3 ,fig4 #beg4 #age4 ,door ,op5]s4 ,fig4 #beg %[s "o =m4 ,!y conta9 electromagnets s arrang$ t :5 ! armature is attract$ by ! pu%+ ( a button any:]e 9 ! build+1 ! door c be pu%$ op54 #agf4 ,d5tal ,outfits4 ,fig4 #beh %[s a motor arrang$ to run d5tal app>atus4 ,! motor c be connect$ to an ord9>y inc&esc5t light socket4 ,9 case ! curr5t gives out1 ! drills1 etc41 c be run by foot p[]4 ,illu/ration3 ,fig4 #beh4 #agg4 ,annunciators ( v>i\s k9ds are us$ 9 hotels1 factories1 etc41 to indicate a c]ta9 room :5 a bell r+s at ! (fice4 ,! bell indicates t "s "o has call$1 & ! annunciator %[s ! location ( ! call by display+ ! numb] ( ! room or its location4 ,fig4 #bei %[s a small annunciator4 ,!y conta9 electromagnets :i* are connect$ to pu%-buttons locat$ 9 ! build+1 & :i* br+ ! numb]s into place z soon z ! curr5t passes ?r\gh !m4 ,illu/ration3 ,fig4 #bei4 ,,index4 ,numb]s ref] to p>agraphs4 ,see ,table ( ,cont5ts = ! titles ( ! v>i\s *apt]s4 ,action ( magnets ^u ea* o!r1 #cb4 ,adju/]1 = lamp cords1 #aea4 ,air pressure1 effect ( sp>k ^u1 #aee4 ,alum9um-leaf1 = electroscopes1 #e4 ,alt]nat+ curr5t1 #abi1 #acj2 sy/em ( wir+ =1 #add4 ,amalgamation ( z9cs1 #dg4 ,amb]1 electrification ^u1 #c4 ,ammet]1 !1 #gd2 h[ plac$ 9 circuit1 #gg4 ,amp]e1 !1 #gb4 ,annunciators1 #agg4 ,anode1 #gi1 #hb4 ,app>atus = electrical measurem5ts1 ,*ap4 ,,vi4 ,appliances1 = di/ribution ( curr5ts1 #ada2 = electric railways1 #afg2 = heat+ by electricity1 #adg4 ,arc1 ! electric1 #aeb4 ,arc lamp1 !1 #aec2 h[ light is produc$ by1 ,*ap4 ,,xxii42 d\ble c>bon1 #aec2 h&-fe$ focuss+1 #aec2 = se>*-lights1 #aec2 %ort1 = basem5ts1 #aec2 s+le c>bon1 #aec2 = !at] use1 #aec4 ,armature1 ( dynamo1 #abg1 #abi2 ( electromagnets1 #ih2 ( horse%oe magnet1 #bf2 ( motors1 #afa2 uses (1 #ci4 ,artificial magnets1 #be4 ,a/atic1 detectors1 #id2 galvanomet]1 #gc2 ne$les1 #id4 ,aurora borealis1 #bc4 ,automatic1 curr5t int]rupt]s1 #ajd1 #aae2 gas light]s1 #agd2 program clocks1 #agb4 ,automobiles1 #afi2 controll]s =1 #afi2 motors =1 #afi2 /e]+ (1 #afi2 /orage batt]ies =1 #afi4 ,bamboo filam5ts1 #adi4 ,b> magnets1 #bg2 magnetic figures (1 #ch4 ,batt]ies1 l>ge plunge1 #ed2 plunge1 #ec2 second>y1 #hf2 /orage1 & h[ !y "w1 ,*ap4 ,,ix4 ,bell1 ! electric1 & "s ( its uses1 ,*ap4 ,,xv42 electric1 #aaf2 magneto te/+1 #aag2 trembl+1 etc41 #aaf4 ,bell transmitt]1 #abj4 ,belts1 electricity g5]at$ by friction ^u1 #a4 ,b5jam9 ,frankl91 #ah4 ,bi*romate ( pota% cells1 #ea1 etc4 ,b9d+-po/s1 ,*ap4 ,v42 common =ms (1 #fc4 ,bla/+1 by electricity1 #adg2 electric ma*9es =1 #adg4 ,blue/one cell1 #ef4 ,boats1 electric1 #afh4 ,boil]s1 use ( 9 c5tral /ations1 #agj4 ,bones1 photograph$ by x-rays1 ,*ap4 ,,xxiii4 ,boo/]s1 #acf4 ,bru%es1 #abi4 ,buns5 cells1 #ef;a4 ,burn]1 automatic1 #agd2 = gas-lights1 #agd2 rat*et1 #agd4 ,buzz]s1 electric1 #aah4 ,cables & wires1 #adc4 ,call boxes1 electric1 #agc4 ,c>bon1 9 arc lamps1 #aeb1 #aec2 filam5t1 #adi2 transmitt]1 #abc4 ,c>pet1 electricity g5]at$ ^u1 #a4 ,c>s1 electric1 #afd2 controll]s =1 #afe2 heat+ by electricity1 #afg2 ov]head sy/em =1 #aff2 und]gr\nd sy/em =1 #aff4 ,cat1 electricity g5]at$ ^u1 #a4 ,ca?ode1 def9ition (1 #gi2 rays1 #aeg4 ,cells1 ,buns51 #ef;a2 bi*romate ( pota%1 #ea2 clos$ circuit1 #ej2 dry1 #eh2 ,edison-,lel&e1 #ei2 electricity g5]at$ by1 ,*ap4 ,,iii42 ,full]1 #ee2 ,gonda1 #eg2 gravity1 #ef2 ,gr5et1 #eb2 ,leclan*1 #eg2 op5 circuit1 #ej2 plates & poles (1 #de;a2 pol>ization (1 #dh2 simple1 #de1 #di2 s+le-fluid1 #di2 two-fluid1 #di2 v>i\s voltaic1 ,*ap4 ,,iv4 ,c5tral /ations1 #agj2 a ^w ab\t1 ,*ap4 ,,xxvi4 ,*a9 lightn+1 #ai4 ,*af+-di%es1 electrical1 #adg4 ,*>g+ cond5s]s1 #ae4 ,*emical action1 & electricity1 #ha4 ,*emical effects ( electric curr5t1 ,*ap4 ,,vii4 ,*emical met]s1 #gh4 ,*ur* organs1 pump$ by motors1 #afb4 ,circuits1 electric1 #ej2 = lamps1 #add4 ,cleats1 porcela91 #ada2 wood51 #ada4 ,clocks1 automatic electric1 #agb4 ,clos$ circuit cells1 #ej4 ,coils1 induction1 & h[ !y "w1 ,*ap4 ,,xiii42 induction1 con/ruction (1 #ajd2 me?od ( jo9+1 #ih2 prim>y & second>y1 #ajc2 resi/ance1 #fi2 rotation (1 #ie2 ( trans=m]s1 #ace4 ,collectors on dynamos1 #abi4 ,commutators1 #abi4 ,compasses1 magnetic1 #ca4 ,comp\nd1 magnets1 #bh2 w\nd dynamo1 #aca4 ,cond5sation ( /atic electricity1 #ae4 ,cond5s]s1 #ae2 = induction coils1 #ajd4 ,conductors1 & insulators1 #d1 #ach4 ,conduits1 electric1 #adj4 ,connections1 electrical1 #fj2 = telegraph l9es1 #aaa4 ,controll]s1 = automobiles1 #afi2 = electric c>s1 #afe4 ,copp] sulphate1 effects ( curr5t on1 #hb2 =mula (1 #gi4 ,copp] voltamet]s1 #ge4 ,cords1 adju/able = lamps1 #aea4 ,c\lomb1 !1 #gf4 ,crat] ( hot c>bons1 #aeb4 ,crookes tubes1 #aef1 #aeh4 ,curr5t1 detectors1 #ic2 direction ( 9 cell1 #df2 f magnet & coil1 #ajj2 f two coils1 #ajb2 induc$1 #abg2 ( induction coils1 #aje2 int]rupt]s1 automatic1 #ajd1 #aae2 local1 #dg2 prim>y & second>y1 #ajb2 trans=mation (1 ,*ap4 ,,xviii42 transmission (1 #acd4 ,curr5ts1 & motion1 #afj2 h[ di/ribut$ = use1 ,*ap4 ,,xix4 ,curr5t /r5g?1 #ga2 measurem5t (1 #gc2 unit (1 #gb4 ,cyl9d] electric ma*9es1 #i4 ,daniell cell1 #ef4 ,d',arsonval galvanomet]1 #gc4 ,decl9ation1 #da4 ,decorative inc&esc5t lamps1 #aea4 ,d5tal1 lamps1 #aea2 outfits1 #agf4 ,detectors1 a/atic1 #id2 curr5t1 #ic4 ,diamagnetic bodies1 #bi4 ,diaphragm = telephones1 #abj4 ,dip1 ( magnetic ne$le1 #db4 ,direct curr5t1 #abi1 #acj4 ,direction ( curr5t 9 cell1 #df4 ,dis*>g+ cond5s]s1 #ae4 ,disruptive dis*>ges1 #aed4 ,di/ribution ( curr5ts = use1 ,*ap4 ,,xix4 ,door op5]1 electric1 #age4 ,dots & da%es1 #aaj4 ,drill press1 run by motor1 #afb4 ,dry cells1 #eh4 ,dynamo1 !1 #abf2 alt]nat+ curr5t1 #acj2 commutator (1 #abi2 comp\nd w\nd1 #aca2 direct curr5t1 #acj2 lamps connect$ to1 #acb2 s]ies w\nd1 #aca2 %unt w\nd1 #aca2 us$ z motor1 #afa2 use ( 9 c5tral /ations1 #agj2 us$ ) wat] p[]1 #agj4 ,dynamos1 electricity g5]at$ by1 ,*ap4 ,,xvii42 types (1 #acj2 v>i\s ma*9es1 #acb2 w9d+ (1 #aca4 ,dynamotors1 #acg4 ,e>?1 inductive influ5ce (1 #dc2 l9es ( =ce ab\t1 #dj1 #db4 ,ebonite1 electricity by friction ^u1 #c1 #d4 ,edison-,lel&e cells1 #ei4 ,electric1 automobiles1 #afi2 bell1 & "s ( its uses1 ,*ap4 ,,xv42 boats1 #afh2 buzz]s1 #aah2 c>s1 #afd2 conduits1 #adj2 fans1 #afb2 flat-irons1 #adf2 gas light]s1 #agd2 griddles1 #adg2 kit*51 #adg2 lights1 arc1 ,*ap4 ,,xxii42 lights1 inc&esc5t1 ,*ap4 ,,xxi42 ma*9es1 /atic1 #g to #ac2 ma*9es1 uses (1 #ad2 motor1 !1 #afa2 motor1 & h[ x does "w1 ,*ap4 ,,xxiv42 sold]+ irons1 #adf2 telegraph1 & h[ x s5ds messages1 ,*ap4 ,,xiv42 telephone1 & h[ x transmits spee*1 ,*ap4 ,,xvi42 weld+1 #adf4 ,electric curr5t1 & "w1 #acc2 & *emical action1 #ha2 *emical effects (1 ,*ap4 ,,vii42 h[ di/ribut$ = use1 ,*ap4 ,,xix42 magnetic effects (1 ,*ap4 ,,xi42 h[ trans=m$1 ,*ap4 ,,xviii4 ,electrical1 connections1 #fj2 horse-p[]1 #gg2 measurem5ts1 ,*ap4 ,,vi42 resi/ance1 #fh2 resi/ance1 unit (1 #fi2 units1 ,*ap4 ,,vi4 ,electricity1 ab\t frictional1 ,*ap4 ,i42 & *emical action1 #ha2 atmosph]ic1 #ah2 heat produc$ by1 ,*ap4 ,,xx42 hi/ory (1 #c2 h[ g5]at$ ^u cat1 #a2 h[ g5]at$ by dynamos1 ,*ap4 ,,xvii42 h[ g5]at$ by heat1 ,*ap4 ,x42 h[ g5]at$ by induction1 ,*ap4 ,,xii42 h[ g5]at$ by voltaic cell1 ,*ap4 ,,iii42 orig9 ( "n1 #b4 ,electrification1 k9ds (1 #f2 laws (1 #g4 ,electrolysis1 #gi4 ,electrolyte1 #gi4 ,electromagnetic induction1 #ii4 ,electromagnetism1 #ia4 ,electromagnets1 #if2 =ms (1 #ig4 ,electro-me*anical gong1 #aaf4 ,electromotive =ce1 def9$1 #fe1 #ga2 measurem5t (1 #fg2 ( pol>ization1 #he2 ( /atic electricity1 #ag2 unit (1 #ff4 ,electrophorus1 !1 #h4 ,electroplat+1 #hb4 ,electroscopes1 #e4 ,electrotyp+1 #hc4 ,exp]im5ts1 e>ly1 ) curr5ts1 #dd2 "s simple1 #a4 ,ext]nal resi/ance1 #fh4 ,fan motors1 #afb4 ,field1 magnetic1 #cg4 ,field-magnets1 #abi4 ,figures1 magnetic1 #ch4 ,filam5ts1 c>bon1 #adi2 bamboo1 etc41 #adi4 ,fire1 ,/4 ,elmo's1 #bb4 ,flat-irons1 electric1 #adg4 ,floor ma9s1 #aci4 ,fluoroscope1 #aeh4 ,=ce1 & induc$ curr5ts1 #aja2 l9es ( magnetic1 #ch2 l9es ( ab\t a wire1 #ib1 #if2 l9es ( ab\t a magnet1 #cg1 #ch4 ,frictional electricity1 ab\t1 ,*ap1 ,i42 location ( *>ge (1 #d2 sp>ks f1 #d4 ,full] cell1 !1 #ee4 ,fuse1 l9k1 #adb2 plug1 #adb2 ribbons1 #adb2 wire1 #adb4 ,fusible rosettes1 #adb4 ,galvani1 e>ly exp]im5ts (1 #dd4 ,galvanomet]s1 #gc2 a/atic1 #gc2 consid]$ z motor1 #afa2 ,d',arsonval1 #gc2 tang5t1 #gc4 ,galvanoscope1 #gc2 a/atic1 #id4 ,gas light]s1 electric1 #agd4 ,geissl] tubes1 #aef4 ,g5]ators1 electric1 #abf4 ,glass1 electricity g5]at$ ^u1 #d4 ,glue pots1 electric1 #adg4 ,gold-leaf1 = electroscopes1 #e4 ,gold plat+1 #hb4 ,gonda cell1 #eg4 ,gong1 electro-me*anical1 #aaf4 ,gravity cell1 !1 #ef2 replac$ by dynamotors1 #acg4 ,gr5et cell1 #eb4 ,griddles1 electric1 #adg4 ,gu>d1 = lamps1 #aea4 ,heat1 h[ g5]at$ by electricity1 ,*ap4 ,x42 & magnetism1 #ce2 & resi/ance1 #ade4 ,heat lightn+1 #ai4 ,heat]s1 = c>s1 #afg4 ,hi/ory ( electricity1 #c4 ,horse-p[]1 electrical1 #gg4 ,horse%oe1 p]man5t magnets1 #bf2 electromagnets1 #ig1 #ih4 ,human body1 bones (1 photograph$ by x-rays1 ,*ap4 ,,xxiii4 ,hydrog51 action ( 9 cell1 #dh2 attraction ( = oxyg51 #he4 ,inc&esc5ce1 #adh4 ,inc&esc5t lamp1 #adi2 c&le-p[] (1 #aej2 curr5t =1 #aej2 light produc$ by1 ,*ap4 ,,xxi42 con/ruction (1 #adi2 uses (1 #aea4 ,incl9ation ( magnetic ne$le1 #db4 ,indicat+ pu%-button1 #fa4 ,induc$ curr5ts1 #abg2 & l9es ( =ce1 #aja2 by rot>y motion1 #abh2 ( induction coils1 #aje2 ( trans=m]s1 #ace4 ,induc$ magnetism1 #cf4 ,induction1 electricity g5]at$ by1 ,*ap4 ,,xii42 electromagnetic1 #ii4 ,induction coils1 cond5s]s =1 #ajd2 con/ruction (1 #ajd2 curr5ts (1 #aje2 h[ !y "w1 ,*ap4 ,,xiii42 9 telephone "w1 #abd2 uses (1 #ajf4 ,inductive influ5ce ( e>?1 #dc4 ,influ5ce ma*9es = m$ical purposes1 #ac4 ,ink writ+ regi/]s1 #aad4 ,insulat+ tub+1 #ada4 ,insulators1 #ada2 & conductors1 #d1 #ach2 fe$]-wire1 #afg2 = poles1 #afg2 porcela91 #ada4 ,int]nal resi/ance1 #fh4 ,int]rupt]s1 automatic curr5t1 #ajd1 #aae4 ,ions1 #hj4 ,iron1 electricity ^u1 by friction1 #d4 ,j>1 ,leyd51 #ae4 ,j>r+ magnets1 effects (1 #cc4 ,keep] ( magnets1 #bf4 ,keys1 telegraph1 #aji4 ,k9ds ( electrification1 #f4 ,kit*51 electric1 #adg4 ,knife swit*1 #fb4 ,lamp1 inc&esc5t1 c&le-p[] (1 #aej2 cord1 adju/able1 #aea2 curr5t =1 #aej2 d5tal1 #aea2 = desks1 #aea2 = ?roat1 #aea2 gu>d =1 #aea2 inc&esc5t1 #adi2 socket1 #aea2 ) half %ade1 #aea4 ,lamp1 ! arc1 #aec2 h[ light is produc$ by1 ,*ap4 ,,xxii42 d\ble c>bon1 #aec2 h&-fe$ focuss+1 #aec2 = se>*-lights1 #aec2 s+le c>bon1 #aec2 %ort1 = basem5ts1 #aec2 = !at] use1 #aec4 ,lamp circuits1 alt]nat+ sy/em1 #add4 ,lamps1 9 p>allel1 #add2 lamps 9 s]ies1 #add2 ?ree-wire sy/em1 #add2 two-wire sy/em1 #add4 ,laws1 ( electrification1 #g2 ( magnetic attraction1 #cb2 ( resi/ance1 #gj4 ,leaf electroscopes1 #e4 ,leclan* cell1 #eg4 ,leyd51 batt]y1 #af2 j>1 #ae4 ,light1 h[ produc$ by arc lamp1 ,*ap4 ,,xxii42 h[ produc$ by inc&esc5t lamp1 ,*ap4 ,,xxi4 ,lightn+1 #ai2 rods1 #ba4 ,l9e1 telegraph1 ,*ap4 ,,xiv42 connections =1 #aaa2 op]ation (1 #aab4 ,l9e susp5sion1 = trolley-wires1 #afg4 ,l9e wire1 #aaa4 ,l9es ( =ce1 conductors (1 #ci1 #if2 ab\t ! e>?1 #dj1 #db2 & induc$ curr5ts1 #aja2 ab\t a magnet1 #ch2 ab\t a wire1 #ib4 ,local curr5ts1 #dg4 ,magnetic1 bodies1 #bi2 decl9ation1 #da2 effects ( electric curr5t1 ,*ap4 ,,xi42 field1 #cg2 figure ( "o b> magnet1 #ch2 figure ( two b> magnets1 #ch2 figure ( horse%oe magnet1 #ch2 ne$le1 dip (1 #db2 ne$les & compasses1 #ca4 ,magnetism1 & heat1 #ce2 induc$1 #cf2 laws (1 #cb2 residual1 #cd2 ret5tivity1 #cd2 tempor>y1 #cf2 t]re/rial1 #dj2 !ory (1 #cc4 ,magneto1 signal bells1 #aag2 te/+ bells1 #aag2 transmitt]1 #abj4 ,magnets1 action ^u ea* o!r1 #cb2 artificial1 #be2 b>1 #bg2 comp\nd1 #bh2 effects ( j>r+1 #cc2 electro1 #if2 electro1 =ms (1 #ig2 horse%oe1 #bf2 & magnetism1 ab\t1 ,*ap4 ,,ii42 mak+ (1 #cj2 natural1 #bd4 ,ma9s1 electric1 #aci4 ,man-holes1 9 conduits1 #adj4 ,measurem5ts1 electric1 ,*ap4 ,,vi42 ( curr5t /r5g?1 #gc2 ( ,e4,m4,f41 #fg4 ,met]s1 *emical1 #gh2 p]man5t record1 #gg4 ,microphone1 !1 #abb4 ,motion & curr5ts1 #afj4 ,motor1 act+ l dynamo1 #afc2 armature (1 #afa2 controll+ spe$ (1 #afe2 electric1 #afa2 electric1 & h[ x does "w1 ,*ap4 ,,xxiv42 fans1 #afb2 = automobiles1 #afi2 = boats1 #afh2 = pump+ bell[s1 #afb2 = runn+ drill press1 #afb2 p>ts (1 #afb2 />t+ boxes =1 #afc2 uses (1 #afb4 ,motor-dynamos1 #acf4 ,m\ld+s1 = wires1 #ada4 ,"n1 electricity1 orig9 (1 #b4 ,natural magnets1 #bd4 ,ne$les1 a/atic1 #id2 dipp+1 #db2 magnetic1 #ca4 ,negative electrification1 #e4 ,non-conductors1 #d4 ,nor? pole1 magnetic ( e>?1 #dj2 ( magnets1 #bf4 ,nor!rn lights1 #bc4 ,ohm1 !1 #fi4 ,op5 circuit cells1 #ej4 ,op5]s1 = doors1 #age4 ,outfits1 d5tal1 #age4 ,ov]head trolley sy/em1 #aff4 ,oxyg51 attraction = hydrog51 #he4 ,p>allel arrangem5t ( lamps1 #add4 ,pelti] effect1 #hi4 ,p5dant1 electric1 #aea4 ,pi?-ball electroscope1 #e4 ,plate electrical ma*9e1 #aj4 ,plates ( cells1 #de;a4 ,plunge batt]ies1 #ec2 l>ge1 #ed4 ,pol>ity ( coils1 #ie4 ,pol>ization1 #hd2 electromotive =ce (1 #he2 ( cells1 #dh4 ,pole-*ang+ swit*1 #fb4 ,poles1 ( cells1 #de;a2 ( horse%oe magnet1 #bf4 ,positive electrification1 #f4 ,pot5tial1 def9$1 #fe4 ,pu%-buttons1 ,*ap4 ,v42 indicat+1 #fa2 modifications (1 #fa2 table clamp1 #fa4 ,quantity ( electricity1 #gf2 unit (1 #gf4 ,rays1 ca?ode1 #aeg2 x-rays1 #aeh4 ,receiv]1 telephone1 #aba4 ,reflectors1 = lamps1 #aea4 ,regi/]s1 ink writ+1 #aad4 ,relay1 !1 #aac4 ,residual magnetism1 #cd4 ,resi/ance1 coils & boxes1 #fi2 electrical1 #fh2 ext]nal1 #fh2 & heat1 #ade2 int]nal1 #fh2 laws (1 #gj2 unit (1 #fi4 ,ret5tivity1 #cd4 ,ris]s1 9 build+s1 #aci4 ,rods1 lightn+1 #ba4 ,ro5tg51 ,pr(41 #aeh4 ,rosette1 fusible1 #adb4 ,runn+-ge>1 ( automobiles1 #afi4 ,safety1 devices1 #adb2 fuse1 #adb2 fuse l9k1 #adb2 fuse plug1 #adb2 fuse ribbon1 #adb2 fuse wire1 #adb4 ,se>*-lights1 #aec2 signals s5t by1 #aec4 ,second>y batt]ies1 #hf2 uses (1 #hg4 ,s]ies arrangem5t ( lamps1 #add4 ,s]ies w\nd dynamo1 #aca4 ,s]vice wires1 #aci4 ,%unt-w\nd dynamo1 #aca4 ,signal bells1 magneto1 #aag4 ,simple cell1 !1 #de1 #di4 ,s+le-fluid cells1 #di4 ,s+le-po9t swit*1 #fb4 ,s+le-/roke bell1 #aaf4 ,socket1 = inc&esc5t lamps1 #aea4 ,sold]+ irons1 electric1 #adg4 ,s\nd]s1 telegraph1 #aaj2 home-made1 #aaj4 ,sp>k1 effect ( air pressure on1 #aee4 ,sp>ks1 f cells1 #ag2 f frictional electricity1 #d4 ,/4 ,elmo's fire1 #bb4 ,/>t+ boxes1 = motors1 #afc4 ,/atic electric ma*9es1 #h4 ,/atic electricity1 cond5sation (1 #ae2 electromotive =ce (1 #ag2 to te/ pres5ce (1 #e2 uses (1 #ad4 ,/eam eng9es1 9 c5tral /ations1 #agj4 ,/eel1 inductive influ5ce ( e>? ^u1 #dc2 ret5tivity (1 #bf4 ,/orage batt]ies1 !1 & h[ !y "w1 ,*ap4 ,,ix42 = automobiles1 #afi2 = boats1 #afh2 = natural s\rces ( p[]1 #hg4 ,/oves1 electric1 #adg4 ,/r5g? ( curr5t1 #ga2 measurem5t (1 #gc2 unit (1 #gb4 ,swit*bo>ds1 #fb4 ,swit*es1 ,*ap4 ,v42 knife1 #fb2 pole-*ang+1 #fb2 s+le po9t1 #fb2 = trolley l9es1 #afg4 ,table clamp-pu%1 #fa4 ,tang5t galvanomet]1 #gc4 ,teakettles1 electric1 #adg4 ,telegraph1 electric1 & h[ x s5ds messages1 ,*ap4 ,,xiv42 ink writ+ regi/]s1 #aad2 keys1 #aji2 relay1 #aac2 s\nd]s1 #aaj4 ,telegraph l9e1 #ajg1 #ajh2 op]ation (1 #aab2 simple connections (1 #aaa4 ,telephone1 !1 & h[ x transmits spee*1 ,*ap4 ,,xvi42 receiv]1 #aba2 transmitt]1 #abj2 use ( induction coil )1 #abd2 v>i\s =ms (1 #abe4 ,tempor>y magnetism1 #cf4 ,t]re/rial magnetism1 #dj4 ,!ory ( magnetism1 #cc4 ,!rmoelectricity1 #hh4 ,!rmopiles1 #ij4 ,?ree-wire sy/em1 #add4 ,?roat1 lamp =1 #aea4 ,?und]1 #bj4 ,toepl]-,holtz ma*9es1 #aa4 ,trans=m]s1 #ace4 ,trans=m+ electric curr5t1 ,*ap4 ,,xviii42 = electric weld+1 #adf4 ,transmission ( curr5ts1 #acd4 ,transmitt]1 ,bell1 #abj2 c>bon1 #abc4 ,trembl+ bell1 #aaf4 ,trolley-wires1 #afd2 -poles1 #afd2 -:eels1 #afd4 ,tubes1 ,crookes1 #aef1 #aeh2 ,geissl]1 #aef2 vacuum1 #aef4 ,two-fluid cells1 #di4 ,two-wire sy/em1 #add4 ,und]gr\nd trolley sy/em #aff2 conduits =1 #aff4 ,unit1 ( curr5t /r5g?1 #gb2 ( electromotive =ce1 #ff2 ( quantity1 #gf2 ( resi/ance1 #fi4 ,units1 electrical1 ,*ap4 ,,vi4 ,uses1 ( armatures1 #ci2 ( electricity1 miscellane\s1 ,*ap4 ,,xxvii42 ( induction coils1 #ajf2 ( motors1 #afb2 ( /orage batt]ies1 #hg4 ,vacuum-tubes1 #aef4 ,v>iation1 angle (1 #da4 ,volt1 !1 #ff4 ,volta1 #ff2 e>ly exp]im5ts (1 #dd4 ,voltaic cell1 electricity g5]at$ by1 ,*ap4 ,,iii4 ,voltaic pile1 #dd4 ,voltamet]s1 #ge2 copp]1 #ge2 wat]1 #ge4 ,voltmet]s1 #fg1 #gg4 ,wat]1 decomposition (1 #gi2 p[]1 s\rce ( en]gy1 #agj2 voltamet]s1 #gc4 ,watt1 !1 #gg4 ,wattmet]s1 #gg4 ,weld+1 electric1 #adf4 ,wim%ur/ electric ma*9e1 #ab4 ,wires & cables1 #adc4 ,wir+1 = alt]nat+ sy/em1 #add2 ?ree-wire sy/em1 #add2 two-wire sy/em1 #add4 ,"w1 & electric curr5t1 #acc4 ,x-ray photographs1 #aei4 ,x-rays1 #aef2 & h[ ! bones ( ! human body are photograph$1 ,*ap4 ,,xxiii4 ,yokes1 #ig1 #ih4 ,z9cs1 amalgamation (1 #dg4 ,,?+s ,a ,,boy ,,%\ld ,,"k ,,ab\t ,,electricity4 ,by ,,?omas ,m4 ,,/4 ,,john1 ,met4 ,e4 ,! book conta9s #ahj pages1 & #bfj illu/rations2 x measures #e x #g 941 & is b\nd 9 clo?4 ,,price1 ,,po/-,,paid1 #a4jj4 ,,cont5ts3 ,*apt] ,i4 ,ab\t ,frictional ,electricity4--,,ii4 ,ab\t ,magnets & ,magnetism4--,,iii4 ,h[ ,electricity is ,g5]at$ by ! ,voltaic ,cell4--,,iv4 ,v>i\s ,voltaic ,cells4--,v4 ,ab\t ,pu%-,buttons1 ,swit*es & ,b9d+-,po/s4--,,vi4 ,units & ,app>atus = ,electrical ,measurem5ts4--,,vii4 ,*emical ,effects ( ! ,electric ,curr5t4--,,viii4 ,h[ ,electroplat+ & ,electrotyp+ are ,done4--,,ix4 ,! ,/orage ,batt]y & ,h[ x ,works4--,x4 ,h[ ,electricity is ,g5]at$ by ,heat4--,,xi4 ,magnetic ,effects ( ! ,electric ,curr5t4--,,xii4 ,h[ ,electricity is ,g5]at$ by ,induction4--,,xiii4 ,h[ ! ,induction ,coil ,works4--,,xiv4 ,! ,electric ,telegraph1 & ,h[ x ,s5ds ,messages4--,,xv4 ,! ,electric ,bell & ,"s ( its ,uses4--,,xvi4 ,! ,telephone1 & ,h[ x ,transmits ,spee*4--,,xvii4 ,h[ ,electricity is ,g5]at$ by ,dynamos4--,,xviii4 ,h[ ! ,electric ,curr5t is ,trans=m$4--,,xix4 ,h[ ,electric ,curr5ts are ,di/ribut$ = ,use4--,,xx4 ,h[ ,heat is ,produc$ by ! ,electric ,curr5t4--,,xxi4 ,h[ ,light is ,produc$ by ! ,inc&esc5t ,lamp4--,,xxii4 ,h[ ,light is ,produc$ by ! ,arc ,lamp4--,,xxiii4 ,x-,rays1 & ,h[ ! ,bones ( ! ,human ,body are ,photograph$4--,,xxiv4 ,! ,electric ,motor & ,h[ x ,does ,"w4--,,xxv4 ,electric ,c>s1 ,boats & ,automobiles4--,,xxvi4 ,a ,^w ,ab\t ,c5tral ,/ations4--,,xxvii4 ,miscellane\s ,uses ( ,electricity4 ,?is book expla9s1 9 simple1 /raight=w>d language1 _m ?+s ab\t electricity2 ?+s 9 :i* ! ,am]ican boy is int5sely int]e/$2 ?+s he wants to "k2 ?+s he %\ld "k4 ,x is free f te*nical language & rhetorical frills1 b x tells h[ ?+s "w1 & :y !y "w4 ,x is brimful ( illu/rations--! be/ t c be _h--illu/rations t are tak5 directly f app>atus & ma*9]y1 & t %[ :at !y are int5d$ to %[4 ,?is book does n conta9 exp]im5ts1 or tell h[ to make app>atus2 our o!r books d t4 ,aft] expla9+ ! simple pr9ciples ( electricity1 x %[s h[ ^! pr9ciples are us$ & comb9$ to make electricity d e-day "w4 ,ev]yone ,%\ld ,"k ,ab\t ,electricity4 ,a ,,v ,,appropriate ,,pres5t ,,?ird ,,edition ,h[ ,two ,boys ,made ,_! ,own ,electrical ,app>atus4 ,conta9+ complete directions = mak+ all k9ds ( simple electrical app>atus = ! /udy ( elem5t>y electricity4 ,by ,,pr(essor ,,?omas ,m4 ,,/4 ,,john1 ,new ,york ,city4 ,! book measures #e #g 941 & is beautifully b\nd 9 clo?4 ,x conta9s #ada pages & #abe illu/rations4 ,complete directions are giv5 = mak+ #aeb diff]5t pieces ( ,app>atus = ! practical use ( /ud5ts1 tea*]s1 & o!rs :o wi% to exp]im5t4 ,,price1 ,,po/-,,paid1 #a4jj4 ,! %ock+ coils1 telegraph in/rum5ts1 batt]ies1 electromagnets1 motors1 etc41 etc41 are s simple 9 con/ruction t any boy ( av]age ability c make !m2 9 fact1 ! illu/rations h be5 made directly f app>atus con/ruct$ by "y boys4 ,! au?or has be5 work+ along ?is l9e = sev]al ye>s1 & he has be5 able1 ) ! help ( boys1 to devise a complete l9e ( simple electrical app>atus4 ,,! ,,app>atus ,,is ,,simple because ! designs & me?ods ( con/ruction h be5 work$ out practically 9 ! s*ool-room1 absolutely no ma*9e-"w be+ requir$4 ,,! ,,app>atus ,,is ,,practical because x has be5 design$ = real use 9 ! exp]im5tal /udy ( elem5t>y electricity4 ,,! ,,app>atus ,,is ,,*eap because mo/ ( ! p>ts c be made ( old t9 cans & crack] boxes1 bolts1 screws1 wires & wood4 ,address1 ,,?omas ,m4 ,,/4 ,,john1 #djg ,we/ #ea/ ,/reet1 ,new ,york4 ,h[ ,two ,boys ,made ,_! ,own ,electrical ,app>atus4 ,,cont5ts3 ,*apt] ,i4 ,cells & ,batt]ies4--,,ii4 ,batt]y ,fluids & ,solutions4--,,iii4 ,miscellane\s ,app>atus & ,me?ods ( ,con/ruction4--,,iv4 ,swit*es & ,cut-,outs4--,v4 ,b9d+-,po/s & ,connectors4--,,vi4 ,p]man5t ,magnets1--,,vii4 ,magnetic ,ne$les & ,compasses4--,,viii4 ,yokes & ,armatures4--,,ix4 ,electro-,magnets4--,x4 ,wire-,w9d+ ,app>atus4--,,xi4 ,induction ,coils & ,_! ,atta*m5ts4--,,xii4 ,contact ,break]s & ,curr5t ,int]rupt]s4--,,xiii4 ,curr5t ,detectors & ,galvanomet]s4--,,xiv4 ,telegraph ,keys & ,s\nd]s4--,,xv4 ,electric ,bells & ,buzz]s4--,,xvi4 ,commutators & ,curr5t ,rev]s]s4--,,xvii4 ,resi/ance ,coils4--,,xviii4 ,app>atus = ,/atic ,electricity4--,,xix4 ,electric ,motors4--,,xx4 ,odds & ,ends4--,,xxi4 ,tools & ,mat]ials4 ,! au?or ( ?is book is a tea*] & wiri] ( great +5uity1 & we imag9e t ! effect ( su* a book z ?is fall+ into juv5ile h&s mu/ be highly /imulat+ & b5eficial4 ,x is full ( explicit details & in/ructions 9 reg>d to a great v>iety ( app>atus1 & ! mat]ials requir$ are all )9 ! compass ( v mode/ pocket-money4 ,moreov]1 x is sy/ematic & entirely )\t rhetorical frills1 s t ! /ud5t c g "r along )\t be+ div]t$ f good helpful "w t w lead him to build useful app>atus & make him und]/& :at he is ab\t4 ,! draw+s are pla9 & excell5t4 ,we he>tily comm5d ! book4--,electrical ,eng9e]4 ,^? :o visit$ ! electrical exhibition la/ ,may _c h fail$ to notice on ! s\? gall]y a v int]e/+ exhibit1 consi/+1 z x did1 ( electrical app>atus made by boys4 ,! v>i\s devices !re %[n1 compris+ electro-magnets1 telegraph keys & s\nd]s1 resi/ance coils1 etc41 7 turn$ out by boys foll[+ ! in/ructions giv5 9 ! book ) ! above title1 :i* is unque/ionably "o ( ! mo/ practical little works yet writt5 t treat ( simil> subjects1 = ) b a limit$ am\nt ( me*anical k1 & by closely foll[+ ! in/ructions giv51 almo/ any electrical device may be made at v small exp5se4 ,t su* a book fills a long-felt want may be inf]r$ f ! numb] ( inquiries we are con/antly receiv+ f p]sons desir+ to make _! own induction coils & o!r app>atus4--,electricity4 ,at ! electrical %[ 9 ,new ,york la/ ,may "o ( ! mo/ int]e/+ exhibits 0 t ( simple electrical app>atus made by ! boys 9 "o ( ! private s*ools 9 ! city4 ,?is app>atus1 made by boys ( ?irte5 to fifte5 ye>s ( age1 0 f designs by ! au?or ( ?is clev] little book1 & x 0 rem>kable to see :at an +5i\s use _h be5 made ( old t9 tomato-cans1 crack]-boxes1 bolts1 screws1 wire1 & wood4 ,) ^! simple mat]ials telegraph in/rum5ts1 coils1 buzz]s1 curr5t detectors1 motors1 swit*es1 armatures1 & an almo/ endless v>iety ( app>atus 7 made1 ,9 ?is book ,mr4 ,/4 ,john has giv5 directions 9 simple language = mak+ & us+ ^! devices1 & has illu/rat$ ^! directions ) admirable diagrams & cuts4 ,! little volume is unique1 & w prove exce$+ly helpful to ^? ( our "y read]s :o are =tunate en\gh to possess !mselves ( a copy4 ,= s*ools :]e a c\rse ( elem5t>y sci5ce is taught1 no bett] text-book 9 ! fir/-/eps 9 electricity is obta9able4--,! ,great ,r\nd ,_w4 ,exhibit ( ,exp]im5tal ,electrical ,app>atus ,,at ,,! ,,electrical ,,%[1 ,,madison ,,squ>e ,,g>d51 ,,new ,,york4 ,:ile only #dj pieces ( simple app>atus 7 %[n 9 ?is exhibit1 x gave visitors some?+ ( an idea ( :at "y boys c d if giv5 prop] designs4 ,illu/ration3 ,,h[ ,,two ,,boys ,,made ,,_! ,,own ,,electrical ,,app>atus ,gives ,prop] ,designs--,designs = ov] #aej ,?+s4 ,fun ,) ,photography ,,book ,,& ,,complete ,,outfit4 ,illu/ration ,,photography is n[ an educational amusem5t1 & to _m x is ! mo/ fasc9at+ ( all amusem5ts4 ,! magic ( sun%9e1 ! wond]s ( nature1 & ! beauties ( art are tools 9 ! h& ( ! amateur photograph]4 ,a great _m ?+s c be done ) ?is outfit1 & x w give an insight into ?is mo/ popul> pa/ime4 ,,! ,,outfit conta9s ev]y?+ necess>y = mak+ ord9>y pr9ts--toge!r ) o!r articles to be us$ 9 v>i\s ways4 ,! foll[+ ?+s are includ$3 ,"o ,illu/rat$ ,book ( ,in/ructions1 call$ ,fun ,) ,photography2 #a ,package ( ,s5sitiz$ ,pap]2 #a ,pr9t+ ,frame1 includ+ ,glass1 ,back1 & ,spr+2 #a ,set ( ,masks = ,pr9t+ ,frame2 #a ,set ( ,patt]ns = ,fancy ,%apes2 #a ,book ( ,negatives 7,pat5t ,p5d+7 ,ready = ,use2 #f ,%eets ( ,blank ,negative ,pap]2 #a ,alphabet ,%eet2 #a ,package ( ,c>d ,m\nts2 #a ,package ( ,fold+ ,m\nts2 #a ,package ( ,fixo4 ,,cont5ts ,,( ,,book3--,*apt] ,i4 ,introduction4--,photography4--,magic ,sun%9e4--,! ,outfit4--,,ii4 ,g5]al ,in/ructions4--,! ,s5sitiz$ ,pap]4--,h[ ! ,effects are ,produc$4--,negatives4--,pr9ts4--,pr9t+ ,frames4--,our ,pr9t+ ,frame4--,putt+ ,negatives 9 ,pr9t+ ,frame4--,pr9t+4--,develop+4--,fix+4--,d ry+4--,trimm+4--,fancy ,%apes4--,m\nt+4--,,iii4 ,negatives & ,h[ to ,make ,!m4--,! ,pap]4--,mak+ ,transp>5t ,pap]4--,mak+ ! ,negatives4--,pr9t$ ,negatives4--,p]=at$ ,negatives4--,negatives ,made f ,magaz9e ,pictures4--,gr\nd ,glass ,negatives4--,,iv4 ,nature ,photography4--,aids to ,nature ,/udy4--,f]ns & ,leaves4--,photograph+ ,leaves4--,p]=at+ ,leaves4--,dry+ ,leaves1 ,f]ns1 etc41 = ,negatives4--,fl[]s4--,v4 ,miscellane\s ,photographs4--,magnetic ,photographs4--,comb9ation ,pictures4--,initial ,pictures4--,"n ,plates4--,*ri/mas1 ,ea/] & ,bir?day ,c>ds4 ,! ,book & ,complete ,outfit w be s5t1 by mail or express1 ,*>ges ,prepaid1 ^u receipt ( #fe ,c5ts1 by ,,?omas ,m4 ,,/4 ,,john1 #djg ,w4 #ea/ ,/41 ,new ,york4 ,fun ,) ,magnetism4 ,,book ,,& ,,complete ,,outfit ,,= ,,sixty-,,"o ,,exp]im5ts ,,9 ,,magnetism444 ,illu/ration ,*ildr5 l to d exp]im5ts2 & 9 ?is way1 bett] ?an 9 any o!r1 a practical k ( ! elem5ts ( magnetism may be obta9$4 ,^! exp]im5ts1 al?\gh arrang$ to amuse boys & girls1 h be5 f\nd to be v useful 9 ! class-room to supplem5t ! ord9>y ex]cises giv5 9 text-books ( sci5ce4 ,to secure ! be/ possible quality ( app>atus1 ! horse%oe magnets 7 made at ,%effield1 ,engl&1 especially = ^! sets4 ,!y are new & /rong4 ,o!r p>ts ( ! app>atus h also be5 select$ & made ) great c>e1 to adapt !m p>ticul>ly to ^! exp]im5ts4--,f ! au?or's preface4 ,,cont5ts4--,exp]im5ts ,) ,horse%oe ,magnet4--,exp]im5ts ,) ,magnetiz$ ,ne$les4--,exp]im5ts ,) ,ne$les1 ,corks1 ,wires1 ,nails1 etc4--,exp]im5ts ,) ,b> ,magnets4--,exp]im5ts ,) ,float+ ,magnets4--,miscellane\s ,exp]im5ts4--,miscellane\s ,illu/rations %[+ :at v small *ildr5 c d ) ! ,app>atus4--,diagrams %[+ h[ ,magnetiz$ ,ne$les may be us$ by little *ildr5 to make hundr$s ( pretty designs ^u pap]4 ,,amus+ ,,exp]im5ts4--,some?+ = ,n]v\s ,p to ,try4--,! ,j]sey ,mosquito4--,! ,/amp$e4--,! ,runaway4--,! ,dog-fight4--,! ,:irligig4--,! ,naval ,battle4--,a ,/r+ ( ,fi%4--,a ,magnetic ,gun4--,a ,top ,upsid$[n4--,a ,magnetic ,w9dmill4--,a ,compass ,upsid$[n4--,! ,magnetic ,acrobat4--,! ,busy ,ant-hill4--,! ,magnetic ,bridge4--,! ,m]ry-g-,r\nd4--,! ,tight-rope ,walk]4--,a ,magnetic ,motor ,us+ ,attractions & ,repulsions4 ,! ,book & ,complete ,outfit w be s5t1 ,po/-paid1 ^u receipt ( #ce ,c5ts1 by ,,?omas ,m4 ,,/4 ,,john1 #djg ,w4 #ea/ ,/41 ,new ,york4 ,,fun ,,) ,,%ad[s ,,book ,,& ,,complete ,,outfit ,,= ,,%ad[ ,,pictures1 ,,pantomimes1 ,,ent]ta9m5ts1 ,etc41 ,etc4 ,illu/ration ,%ad[ ,mak+ has be5 a v popul> amusem5t = sev]al c5turies4 ,!re is a great deal ( fun & in/ruction 9 x1 & its long life is due to ! fact t x has always be5 a s\rce ( ke5 delight to gr[n p z well z to *ildr54 ,9 gett+ mat]ial toge!r = ?is little book1 ! au?or has be5 greatly aid$ by ,engli%1 ,fr5* & ,am]ican au?ors1 "s ( :om are pr(essional %ad[i/s4 ,x has be5 ! au?or's special ef=t to get ! subject & app>atus into a practical1 *eap =m = boys & girls4 ,,! ,,outfit conta9s ev]y?+ necess>y = all ord9>y %ad[ pictures1 %ad[ ent]ta9m5ts1 %ad[ plays1 etc4 ,! foll[+ articles are includ$3 ,"o book ( ,in/ructions call$ ,fun ) ,%ad[s2 #a ,%ad[ ,scre52 #b ,%eets ( ,trac+ ,pap]2 #a ,coil ( ,wire = ,movable ,figures2 #a ,c>dbo>d ,frame = ,circul> ,scre52 #a ,c>dbo>d ,h\se = ,/age ,sc5]y2 #a ,jo9t$ ,wire ,fi%-pole & ,l9e2 #b ,b5t ,wire ,sc5]y ,hold]s2 #d ,clamps = ,scre52 #a ,wire ,figure ,support2 #a ,wire = ,o>2 #b ,spr+ ,wire ,table ,clamps2 #a ,wire ,c&le/ick ,hold]2 #e ,c>dbo>d ,plates conta9+ ! foll[+ pr9t$ figures t %\ld be cut out ) %e>s3 #ab ,"* ,hats2 #a ,boat2 #a ,o>-blade2 #a ,fi%2 #a ,c&le/ick2 #a ,c>dbo>d ,plate conta9+ pr9t$ p>ts = mak+ movable figures4 ,,cont5ts ,,( ,,book3 ,"o ,hundr$ ,illu/rations & ,diagrams1 includ+ ,t5 ,full-page ,book ,plates1 toge!r ) ,six ,full-page ,plates on ,c>dbo>d4 ,*apt] ,i4 ,introduction4--,,ii4 ,g5]al ,in/ructions4--,,iii4 ,h& ,%ad[s ( ,animals4--,,iv4 ,h& ,%ad[s ( ,heads1 ,"* ,faces1 etc4--,v4 ,mov+ ,%ad[ ,figures & ,h[ to ,make ,!m4--,,vi4 ,%ad[ ,pantomimes4--,,vii4 ,miscellane\s ,%ad[s4 ,! ,book & ,complete ,outfit w be s5t1 ,,po/-,,paid1 ^u receipt ( #ce c5ts1 by ,,?omas ,m4 ,,/4 ,,john1 #djg ,we/ #ea/ ,/41 ,new ,york ,city4 ,fun ,) ,electricity4 ,,book ,,& ,,complete ,,outfit ,,= ,,sixty ,,exp]im5ts ,,9 ,,electricity4444 ,illu/ration ,en\gh ( ! pr9ciples ( electricity are br\ght out to make ! book in/ructive z well z amus+4 ,! exp]im5ts are sy/ematically arrang$1 & make a fasc9at+ sci5ce c\rse4 ,no *emicals1 no dang]4 ,! book is conv]sational & n at all s*ooly1 ,h>ry & ,n$ be+ two boys :o p]=m ! exp]im5ts & talk ov] ! results z !y g along4 ,! book reads l a /ory4--,an appropriate pres5t = a boy or girl4--,intellig5t p>5ts w appreciate ',fun ,) ,electricity4'--,v complete1 because x conta9s bo? book & app>atus4--,!re is no end to ! fun :i* a boy or girl c h ) ?is fasc9at+ amusem5t4 ,,!re ,,is ,,fun ,,9 ,,^! ,,exp]im5ts4--,*a9 ,lightn+4--,an ,electric ,:irligig4--,! ,baby ,?und]/orm4--,a ,race ) ,electricity4--,an ,electric ,frog ,pond4--,an ,electric ,d+-,dong4--,! ,magic ,f+]4--,daddy ,long-,legs4--,jump+ ,sally4--,an ,electric ,kite4--,v ,%ock+4--,cond5s$ ,lightn+4--,an ,electric ,fly-,trap4--,! ,m]ry ,p5dulum4--,an ,electric ,f]ry-,boat4--,a ,funny ,piece ( ,pap]4--,a ,joke on ! ,family ,cat4--,electricity ,plays ,leap-,frog4--,lightn+ ,goes ,ov] a ,bridge4--,electricity ,c>ries a ,lant]n4--,& #dj ,o!rs4 ,! ,,outfit conta9s #bj diff]5t articles4 ,! ,,book ,,( ,,in/ruction measures #e x #g in*es1 & has #ch illu/rations1 #ee pages1 good pap] & cle> type4 ,! ,book1 & ,complete ,outfit w be s5t1 by mail or express1 ,*>ges ,prepaid1 ^u receipt ( #fe ,c5ts1 by ,,?omas ,m4 ,,/4 ,,john1 #djg ,w4 #ea/ ,/41 ,new ,york4 ,fun ,) ,puzzles4 ,,book1 ,,key1 ,,& ,,complete ,,outfit ,,= ,,f\r ,,hundr$ ,,puzzles444 ,! ,,book measures #e #g in*es4 ,x is well pr9t$1 nicely b\nd1 & conta9s #ae *apt]s1 #hj pages1 & #abh illu/rations4 ,! ,,key is illu/rat$4 ,x is b\nd ) ! book1 & conta9s ! solution ( e puzzle4 ,! ,,complete ,,outfit is plac$ 9 a neat box ) ! book4 ,x consi/s ( numb]s1 c\nt]s1 figures1 pictures1 etc41 = do+ ! puzzles4 ,,cont5ts3 ,*apt] 7#a7 ,secret ,writ+4 7#b7 ,magic ,triangles1 ,squ>es1 ,rectangles1 ,hexagons1 ,crosses1 ,circles1 etc4 7#c7 ,dropp$ ,lett] & ,dropp$ ,^w ,puzzles4 7#d7 ,mix$ ,prov]bs1 ,prose & ,rhyme4 7#e7 ,^w ,diamonds1 ,squ>es1 ,triangles1 & ,rhomboids4 7#f7 ,num]ical ,enigmas4 7#g7 ,jumbl$ ,writ+ & ,magic ,prov]bs4 7#h7 ,dissect$ ,puzzles4 7#i7 ,hidd5 & ,conceal$ ,words4 7#aj7 ,divid$ ,cakes1 ,pies1 ,g>d5s1 ,f>ms1 etc4 7#aa7 ,bicycle & ,boat ,puzzles4 7#ab7 ,v>i\s ,^w & ,lett] ,puzzles4 7#ac7 ,puzzles ) ,c\nt]s4 7#ad7 ,comb9ation ,puzzles4 7#ae7 ,mazes & ,labyr9?s4 ,fun ,) ,puzzles is a book t e boy & girl %\ld h4 ,x is amus+1 in/ructive1--educational4 ,x is j ! ?+ to wake up boys & girls & make !m ?9k4 ,!y l x1 because x is real fun4 ,?is sort ( educational play %\ld be giv5 9 e s*ool-room & 9 e home4 ,fun ,) ,puzzles w puzzle y\r fri5ds1 z well z y\rself2 x conta9s "s real bra9-splitt]s4 ,ov] #cjj new & orig9al puzzles are giv51 besides _m t are hundr$s ( ye>s old4 ,secret ,writ+4 ,among ! _m ?+s t ,f4 ,w4 ,p4 conta9s1 is ! key to secret writ+4 ,x %[s y a v simple way to write lett]s to y\r fri5ds1 & x is simply impossible = o!rs to read :at y h writt51 unless !y "k ! secret4 ,?is1 alone is a valuable ?+ = any boy or girl :o wants to h "s fun4 ,! ,book1 ,key1 & ,complete ,outfit w be s5t1 po/paid1 ^u receipt ( #ce c5ts1 by ,,?omas ,m4 ,,/4 ,,john1 #djg ,we/ #ea/ ,/41 ,new ,york ,city4 ,fun ,) ,soap-,bubbles4 ,,book ,,& ,,complete ,,outfit ,,= ,,fancy ,,bubbles ,,& ,,films4444 ,illu/ration ,,! ,,outfit conta9s ev]y?+ necess>y = ?\s&s ( beautiful bubbles & films4 ,all highly color$ articles h be5 c>efully avoid$1 z *eap pa9ts & dyes are positively dang]\s 9 *ildr5's m\?s4 ,! outfit conta9s ! foll[+ articles3 ,"o ,book ( ,in/ructions1 call$ ,fun ,) ,soap-,bubbles1 #a ,metal ,base = ,bubble ,/&1 #a ,wood5 ,rod = ,bubble ,/&1 #c ,l>ge ,wire ,r+s = ,bubble ,/&1 #a ,small ,wire ,r+1 #c ,/raws1 #a ,package ( ,prep>$ ,soap1 #a ,bubble ,pipe1 #a ,wat]-pro( ,bubble ,horn4 ,! complete outfit is plac$ 9 a neat box ) ! book4 7,extra ,horns1 ,soap1 etc41 furni%$ at slight co/47 ,,cont5ts ,,( ,,book4--,tw5ty-"o ,illu/rations4--,introduction4--,! ,colors ( ,soap-bubbles4--,! ,outfit4--,soap ,mixture4--,useful ,h9ts4--,bubbles ,bl[n ,) ,pipes4--,bubbles ,bl[n ,) ,/raws4--,bubbles ,bl[n ,) ! ,horn4--,float+ ,bubbles4--,baby ,bubbles4--,smoke ,bubbles4--,bomb%ell ,bubbles4--,danc+ ,bubbles4--,bubble ,games4--,support$ ,bubbles4--,bubble ,clu/]4--,susp5d$ ,bubbles4--,bubble ,lamp ,*imney4--,bubble ,l5ses4--,bubble ,basket4--,bubble ,bell[s4--,to ,draw a ,bubble ,?r\gh a ,r+4--,bubble ,acorn4--,bubble ,bottle4--,a ,bubble ,)9 a ,bubble4--,ano!r ,way4--,bubble ,%ade4--,bubble ,hammock4--,wre/l+ ,bubbles4--,a ,smok+ ,bubble4--,soap ,films4--,! ,t5nis ,racket ,film4--,fi%-net ,film4--,pan-%ap$ ,film4--,b[ & ,arr[ ,film4--,bubble ,dome4--,d\ble ,bubble ,dome4--,pyramid ,bubbles4--,turtle-back ,bubbles4--,soap-bubbles & ,frictional ,electricity4 ,!re is no?+ m beautiful ?an ! airy-fairy soap-bubble ) its ev]*ang+ colors4 ,,! ,,be/ ,,possible ,,amusem5t ,,= ,,old ,,& ,,"y4 ,! ,book & ,complete ,outfit w be s5t1 ,,po/-,,paid1 ^u receipt ( #ce c5ts1 by ,,?omas ,m4 ,,/4 ,,john1 #djg ,we/ #ea/ ,/41 ,new ,york ,city4 ,! ,/udy ( ,elem5t>y ,electricity & ,magnetism by ,exp]im5t4 ,by ,,?omas ,m4 ,,/4 ,,john1 ,met4 ,e4 ,! book conta9s #bbj pages & #afh illu/rations2 x measures #e #g 94 & is b\nd 9 gre5 clo?4 ,,price1 ,,po/-,,paid1 #a4be4 ,?is book is design$ z a text-book = amateurs1 /ud5ts1 & o!rs :o wi% to take up a sy/ematic c\rse ( elem5t>y electrical exp]im5ts at home or 9 s*ool4 ,full directions are giv5 =4444444 ,two ,hundr$ ,simple ,exp]im5ts4 ,! exp]im5ts are discuss$ by ! au?or1 aft] ! /ud5t has be5 l$ to =m 8 own op9ion ab\t ! results obta9$ & ! po9ts le>n$4 ,9 select+ ! app>atus = ! exp]im5ts 9 ?is book1 ! au?or has kept con/antly 9 m9d ! fact t ! av]age /ud5t w n buy ! exp5sive pieces usually describ$ 9 text-books4 ,! two hundr$ exp]im5ts giv5 c be p]=m$ ) simple app>atus2 9 fact1 ! /ud5t %\ld make at lea/ a "p ( 8 own app>atus1 & = ! b5efit ( ^? :o wi% to d ?is1 ! au?or has giv51 ?r\gh\t ! "w1 explanations t w aid 9 ! con/ruction ( c]ta9 pieces especially adapt$ to ^! exp]im5ts4 ,= ^? :o h ! au?or's ,h[ ,two ,boys ,made ,_! ,own ,electrical ,app>atus1 con/ant ref]5ces h be5 made to x z ! ,app>atus ,book1 z ?is conta9s full details = mak+ almo/ all k9ds ( simple app>atus ne$$ 9 ,! ,/udy ( ,elem5t>y ,electricity & ,magnetism by ,exp]im5t4 ,if y wi% to take up a sy/ematic c\rse ( exp]im5ts--exp]im5ts t may be p]=m$ ) simple1 inexp5sive app>atus1--?is book w s]ve z a valuable guide4 ,cond5s$ ,li/ ( ,app>atus ,,= ,! ,/udy ( ,elem5t>y ,electricity & ,magnetism by ,exp]im5t4 ,numb] #a4 ,/eel ,ne$les2 package ( tw5ty-five4--#b4 ,flat ,cork4--#c4 ,c&le4--#d-ae4 ,anneal$ ,iron ,wires2 assort$ l5g?s4--#af4 ,horse%oe ,magnet2 be/ quality2 ,engli%4--#ag4 ,iron ,fil+s4--#ah4 ,p>ts = ,compass4--#ai1 #bj4 ,wire ,nails2 s(t /eel4--#ba1 #bb4 ,spr+ ,/eel2 = b> magnets4--#bc4 ,iron ,r+4--#bd4 ,sift]2 = iron fil+s4--#be4 ,spr+ ,/eel2 = flexible magnet4--#bf1 #bg4 ,ebonite ,%eets2 ) special surface4--#bh4 ,ebonite ,rod4--#bi4 ,ebonite ,rod2 %ort4--#cj4 ,flannel ,clo?4--#ca4 ,tissue ,pap]4--#cb4 ,cotton ,?read4--#cc4 ,silk ,?read4--#cd4 ,support ,base4--#ce4 ,support ,rod4--#cf4 ,support ,wire4--#cg4 ,wire ,sw+4--#ch4 ,%eet ( ,glass4--#ci4 ,hairp94--#dj4 ,circul> ,conductor4--#da4 ,circul> ,conductor4--#db4 ,electrophorus ,cov]4--#dc4 ,insulat+ ,table4--#dd4 ,insulat$ ,copp] ,wire4--#de4 ,rubb] ,b&4--#df4 ,b5t ,wire ,clamps4--#dg4 ,cyl9drical ,conductor4--#dh4 ,dis*>g]2 = cond5s]4--#di4 ,alum9um-,leaf4--#ej4 ,wires4 #ea4 ,dry ,cell4--#eb4 ,m]cury4--#ec4 ,insulat$ ,copp] ,wire2 = connections4--#ed4 ,spr+ ,connectors2 two doz54--#ee4 ,p>ts = ,key4--#ef4 ,metal ,connect+ ,plates4--#eg4 ,p>ts = ,curr5t ,rev]s]4--#eh4 ,p>ts = ,galvanoscope4--#ei4 ,p>ts = ,a/atic ,galvanoscope4--#fj-fc4 ,z9c ,/rips4--#fd4 ,c>bon ,rod4--#fe1 #ff4 ,glass ,tumbl]s4--#fg1 #fh4 ,copp] ,/rips4--#fi4 ,galvaniz$ ,iron ,nail4--#gj1 #ga4 ,wood5 ,cross-,pieces4--#gb4 ,brass ,screws2 "o doz54--#gc4 ,por\s ,cup4--#gd4 ,z9c ,rod4--#ge4 ,copp] ,plate4--#gf4 ,iron ,/rip4--#gg1 #gh4 ,lead ,/rips4--#gi4 ,p>ts = ,resi/ance ,coil4--#hj4 ,p>ts = ,:eat/one's ,bridge4--#ha4 ,g]man-,silv] ,wire2 ,size ,no4 #cj4--hb4 ,g]man-,silv] ,wire2 ,no4 #bh4--hc--he4 ,plate ,b9d+-,po/s4--#hf4 ,copp] ,sulphate4--#hg4 ,copp] ,burs2 "o doz54--#hh4 ,comb9ation ,rule4--#hi4 ,coil ( ,wire2 on spool = electromagnet4--#ij4 ,coil ( ,wire2 on spool = electromagnet4--#ia4 ,c>bon ,rod4--#ib1 #ic4 ,s(t ,iron ,cores ) ,screws4--#id4 ,comb9$ ,base & ,yoke4--#ie4 ,comb9ation ,connect+ ,plates4--#if4 ,long ,iron ,core4--#ig4 ,r\nd ,b> ,magnet1 #e #c_/h 94--#ih4 ,?9 ,electromagnet4--#ii4 ,degree-,c>d2 = galvanoscope4--#ajj4 ,scale = ,bridge4--#aja1 #ajb4 ,s(t ,iron ,cores ) ,heads4--#ajc1 #ajd4 ,flat ,b> ,magnets2 ^! are #f 942 highly poli%$ /eel2 poles m>k$4--#aje4 ,compass4 ,illu/rat$ ,price ,catalogue ^u ,application4 ,electrical ,app>atus ,= ,sale ,a ,,complete ,,electric ,,& ,,magnetic ,,cab9et ,,= ,,/ud5ts1 ,,s*ools ,,& ,,amateurs4 ,,six ,,extraord9>y ,,(f]s ,?is ,cab9et ( ,electrical ,exp]im5ts conta9s ?ree ma9 p>ts3 7,a7 ,app>atus2 7,b7 ,text-,book2 7,c7 ,app>atus ,li/4 7,a7 ,! ,app>atus furni%$ consi/s ( "o hundr$ & five pieces4 ,ov] ?ree hundr$ sep>ate articles are us$ 9 mak+ up ?is set4 ,mo/ ( x is ready = use :5 receiv$4 ,sev5 pieces1 h[ev]1 are n assembl$2 b ! p>ts c be readily f9i%$ & put toge!r4 7,sold1 also1 all pieces assembl$47 7,b7 ,! ,text-,book--call$ ,! ,/udy ( ,elem5t>y ,electricity & ,magnetism by ,exp]im5t--gives full directions = two hundr$ exp]im5ts4 7,see table ( cont5ts1 etc47 ,price1 po/-paid1 #a4be4 7,c7 ,! ,app>atus ,li/ is an illu/rat$ book devot$ entirely to ?is special set ( app>atus4 ,n giv5 ) fir/ (f]4 ,,! ,,app>atus ,,is ,,simple because ! designs & me?ods ( con/ruction h be5 work$ out ) great c>e4 ,,! ,,app>atus ,,is ,,practical because x has be5 design$ = real use 9 ,! ,/udy ( ,elem5t>y ,electricity & ,magnetism by ,exp]im5t4 ,,! ,,app>atus ,,is ,,*eap because ! v>i\s p>ts are s design$ t !y c be turn$ out 9 quantity by ma*9]y4 #a/ ,(f]3 ,pieces #a to #ej #a4jj #b;d ,(f]3 ,pieces #ea to #aje1 ) "p 7,c7 #c4ej #c;d ,(f]3 ,pieces #a to #aje1 ) "p 7,c7 #d4jj #d? ,(f]3 ,complete ,cab9et1 p>ts 7,a71 7,b71 7,c7 #e4jj #e? ,(f]3 ,app>atus only1 all pieces assembl$ #d4fj #f? ,(f]3 ,complete ,cab9et1 all pieces assembl$ #e4fj ,express *>ges mu/ be paid by y4 ,e/imates giv54 ,a ,special ,catalogue1 p]ta9+ to ! above1 ) complete price-li/1 w be mail$ ^u application4 ,,?omas ,m4 ,,/4 ,,john1 #djg ,we/ #ea/ ,/41 ,new ,york ,city ,fun ,) ,telegraphy ,,book ,,& ,,complete ,,outfit4 ,illu/ration ,,telegraphy is ( ! greate/ importance to all civiliz$ nations1 & ^u x dep5d "s ( ! _w's mo/ important ent]prises4 ,e boy & girl c make practical use ( telegraphy 9 "o way or ano!r1 & ! "t x takes to le>n x w be well sp5t4 ,,! ,,outfit4--,mr4 ,/4 ,john has work$ = a numb] ( ye>s to produce a telegraph outfit t w\ld be simple1 *eap1 & practical = ^? :o wi% to make a /udy ( telegraphy4 ,aft] mak+ & exp]im5t+ ) ne>ly "o hundr$ models1 _m ( :i* 7 good1 he has at la/ p]fect$ an in/rum5t s simple1 orig9al1 & effective t x is n[ be+ made 9 l>ge quantities4 ,! s\nd]s are s design$ t !y w "w prop]ly ) any dry cell ( ord9>y /r5g?1 & ?is is a great advantage = practice l9es4 ,dry batt]ies are *eap & clean1 & !re are no dang]s f acids4 ,! outfit consi/s ( ! foll[+ articles1 plac$ 9 a neat box3 ,"o ,book ( ,in/ruction1 call$ ,fun ,) ,telegraphy2 "o ,telegraph ,key2 "o ,telegraph ,s\nd]2 ,insulat$ ,copp] ,wires = connections4 ,! key & s\nd] are m\nt$1 ) prop] b9d+-po/s1 ^u a base ( peculi> con/ruction1 :i* aids 9 giv+ a l>ge volume ( s\nd4 ,,cont5ts ,,( ,,book4--,telegraphy4--,! ,outfit4--,a ,complete ,telegraph ,l9e4--,connections4--,! ,telegraph ,key4--,! ,s\nd]4--,! ,batt]y4--,a ,practice ,l9e4--,a ,two-in/rum5t ,l9e4--,op]ation ( ,l9e4--,! ,morse ,telegraph ,alphabet4--,aids to ,le>n+ ,alphabet4--,cautions4--,(fice ,calls4--,receiv+ ,messages4--,rememb]4--,extra ,p>ts4 ,,ab\t ,,batt]ies4--,= ^? :o _c easily secure batt]ies1 we w furni% small dry cells1 po/-paid1 at #ae c5ts ea*1 9 ord] to deliv] ! outfits complete to our cu/om]s4 ,?is price b>ely cov]s ! total co/ to u1 po/age alone be+ #f c5ts4 ,,fun ,,) ,,telegraphy1 includ+ ,book1 ,key1 ,s\nd]1 & ,wire 7no batt]y71 po/-paid1 #ej c5ts1 by ,,?omas ,m4 ,,/4 ,,john1 #hdh ,n9? ,ave41 ,new ,york ,tool ,sets = ,/ud5ts ,! foll[+ tool sets h be5 arrang$ especially = ^? :o wi% to make use ( ! designs conta9$ 9 ,h[ ,two ,boys ,made ,_! ,own ,electrical ,app>atus1 ,real ,electric ,toy-,mak+ = ,boys1 ,electric ,in/rum5t-,mak+1 etc4 ,x is v poor economy to wa/e valuable "t & en]gy 9 ord] to save ! co/ ( a few extra tools4 ,,note4--,save money by buy+ y\r tools 9 sets4 ,we d n pay express or freight *>ges at ! special prices bel[4 ,,= #a4jj4--,"o ,/eel ,pun*2 r\nd1 knurl$ head4--,"o light ,hamm]2 poli%$1 nickel-plat$1 v>ni%$ h&le4--,"o ,iron ,clamp2 japann$1 #b 94--,"o ,screw-,driv]2 temp]$ & poli%$ blade1 *]ry /a9$ h>dwood h&le1 nickel f]rule4--,"o ,wr5*2 ret9n$ skeleton frame1 gilt adju/+ :eel4--,"o ,awl2 temp]$ /eel po9t1 turn$ & /a9$ wood h&le1 ) f]rule4--,"o ,vise2 full malleable1 nicely ret9n$1 #a-c_/h 94 jaws1 full malleable screw ) spr+4--,"o pair ,/eel ,pli]s2 #d 94 long1 poli%$ tool /eel1 unbreakable1 be/ groov$ jaw4--,"o pair ( ,%e>s2 c>boniz$ /eel blades1 h>d5$ edge1 nickel-plat$1 heavy brass nut & bolt4--,"o ,file2 triangul>1 good /eel4--,"o ,file ,h&le2 good wood1 brass f]rule4--,"o ,foot ,rule2 v>ni%$ wood1 has ,engli% & metric sy/em4--,"o ,sold]+ ,set2 conta9s sold]+ iron1 sold]1 res91 sal ammoniac1 & directions4 ,"o ,c5t]-,pun*2 f9ely temp]$ /eel4 ,,= #b4jj4--;,all t is conta9$ 9 ! #a4jj set ( tools1 toge!r ) ! foll[+3 ,"o pair ( ,t9n]'s ,%e>s2 cut1 #b 941 ca/ iron1 h>d5$1 suitable = cutt+ ?9 metal4--,"o ,holl[ ,h&le ,tool ,set2 v useful2 poli%$ h&le holds #aj tools1 gimlet1 brad-awls1 *isel1 etc4--,"o ,try ,squ>e2 #f-;94 blue /eel blade1 m>k$ 9 #a_/hs1 /rongly rivet$4--,"o #a-lb4 ,hamm]2 full size1 poli%$ head1 w$g$ v>ni%$ h>dwood h&le4--,"o ,hack ,saw2 /eel frame1 #i-;94 poli%$ /eel blade1 black enamel h&le2 v useful4 ,,= #c4ej4--,two ,/eel ,pun*es2 diff]5t sizes1 "o solid r\nd1 knurl$ head1 poli%$2 ! o!r1 po9t & head brightly poli%$1 full nickel1 c5t] "p knurl$4--,"o ,light ,hamm]2 poli%$ & nickel plat$1 v>ni%$ h&le4--,"o regul> ,ma*9i/'s ,hamm]2 ball pe51 solid ca/ /eel1 ) v>ni%$ h>dwood h&le2 a sup]ior article4--,two ,iron ,clamps2 "o op5s #b 941 ! o!r #c 941 japann$4--,"o ,screw-,driv]2 temp]$ & poli%$ blade1 firmly set 9 *]ry /a9$ h>dwood h&le ) nickel f]rule4--,"o ,wr5*2 ret9n$1 skeleton frame1 gilt adju/+ :eel4--,"o ,awl2 temp]$ /eel blade1 gr\nd to po9t1 firmly set 9 turn$ & /a9$ h&le ) f]rule4--,"o ,/eel ,vise2 #b-;941 jaws1 /eel screw1 bright poli%$ jaws & h&le2 a good /rong vise4--,"o pair ( ,/eel ,pli]s2 #f 94 long1 bright /eel1 flat nose1 #b wire-cutt]s1 practically unbreakable4--,"o pair ( ,%e>s2 c>boniz$ /eel blades1 h>d5$ edges1 nickel plat$1 heavy brass nut & bolt4--,"o ,file2 triangul> & ( good /eel4--,"o ,file ,h&le2 good wood1 ) brass f]rule4--,"o ,foot ,rule2 v>ni%$ wood1 has bo? ! ,engli% & metric sy/ems4--,"o ,sold]+ ,set2 conta9s sold]+ iron1 sold]1 res91 sal ammoniac1 & directions2 a v h&y article4--,"o ,c5t]-,pun*2 f9ely temp]$ /eel4--,"o pair ( ,t9n]'s ,%e>s2 ^! are be/ grade1 inlaid /eel cutt+ edges1 poli%$ & temp]$1 japann$ h&les2 ?or\ghly reliable4--,"o ,holl[ ,h&le ,tool ,set2 v useful2 ! poli%$ h&le holds #aj tools1 gimlet1 *isel1 brad-awl1 etc4--,"o ,try ,squ>e2 #f-;94 blue /eel blade1 m>k$ bo? sides 9 #a_/hs1 /rongly rivet$ ) brass rivets4--,"o ,hack ,saw2 /eel frame1 #i-;94 poli%$ /eel blade1 black enamel h&le2 v useful = saw+ small pieces ( wood4 ,,= #e4jj w be includ$ ev]y?+ 9 ! #c4ej (f]1 & ! foll[+3 ,"o ,glue-,pot2 m$ium size1 ) bru% & be/ wood glue2 inside pot has h+e cov]4--,"o ,rat*et ,screw-,driv]2 great improvem5t ov] ord9>y screw-driv]s2 well made & useful4--,"o ,h& ,drill2 frame malleable iron2 holl[ screw top hold+ #f drills2 bores f #a-af to #c-af-;94 holes2 solid ge> tee?2 #c-;jaw$ nickel plat$ *uck2 a sup]ior tool1 & almo/ a necessity4 ,,give ,,! ,,boy ,a ,,set ,,( ,,tools ,,?omas ,m4 ,,/4 ,,john1 #hdh ,n9? ,ave41 ,new ,york ,,real ,,electric ,,toy-,,mak+ ,,= ,,boys ,by ,,?omas ,m4 ,,/4 ,,john1 ,met4 ,e4 ,?is book conta9s #adj pages & ov] "o hundr$ orig9al draw+s1 diagrams1 & full-page plates4 ,x measures #e x #g 941 & is b\nd 9 clo?4 ,price1 po/-paid1 #a4jj ,,cont5ts3 ,*apt] ,i4 ,toys ,op]at$ by ,p]man5t ,magnets4--,,ii4 ,toys ,op]at$ by ,/atic ,electricity4--,,iii4 ,mak+ ,electromagnets = ,toys4--,,iv4 ,electric ,batt]ies4--,v4 ,circuits & ,connections4--,,vi4 ,toys ,op]at$ by ,electromagnets4 ,,vii4 ,mak+ ,sol5oids = ,toys4--,,viii4 ,toys ,op]at$ by ,sol5oids4--,,ix4 ,electric ,motors4--,x4 ,p[]1 ,spe$1 & ,ge>+4--,,xi4 ,%aft+ & ,be>+s4--,,xii4 ,pulleys & ,w9d+-,drums4--,,xiii4 ,belts & ,cables4--,,xiv4 ,toys ,op]at$ by ,electric ,motors4--,,xv4 ,miscellane\s ,electric ,toys4--,,xvi4 ,tools4--,,xvii4 ,mat]ials4--,,xviii4 ,v>i\s ,aids to ,con/ruction4 ,:ile plann+ ?is book1 ,mr4 ,/4 ,john def9itely decid$ t he w\ld n fill x ) descriptions ( complicat$1 ma*9e-made in/rum5ts & app>atus1 "u ! "n ( ,toy-,mak+1 = x is j z impossible = mo/ boys to get ! p>ts = su* ?+s z x is = !m to d ! requir$ ma*9e "w ev5 aft] !y h ! raw mat]ials4 ,great c>e has be5 tak5 9 design+ ! toys :i* are describ$ 9 ?is book1 9 ord] to make !m s simple t any boy ( av]age ability c con/ruct !m out ( ord9>y mat]ials4 ,! au?or c p]sonally gu>antee ! designs1 = !re is no guesswork ab\t !m4 ,e toy 0 made1 *ang$1 & exp]im5t$ ) until x 0 z simple z possible2 ! draw+s 7 !n made f ! p]fect$ models4 ,z ! result ( ! enorm\s am\nt ( "w & exp]im5t+ :i* 7 requir$ to orig9ate & p]fect s _m new models1 ! au?or feels t ?is book may be truly call$ ,real ,electric ,toy-,mak+ = ,boys4 ,e ,boy ,%\ld ,make ,electrical ,toys4 ,! ,electric ,%oot+ ,game ,a ,,mo/ ,,orig9al ,,& ,,fasc9at+ ,,game ,,pat5t ,,appli$ ,,= ,,& ,,copyright$ ,illu/ration ,,%oot+ ,,by ,,electricity ,! ,electric ,%oot+ ,game is an entirely new idea1 & "o t br+s into use t mo/ my/]i\s some?+--electricity4 ,! game is s simple t small *ildr5 c play x1 & z !re are no batt]ies1 acids1 or liquids ( any k9d1 !re is absolutely no dang]4 ,! electricity is ( su* a nature t x is p]fectly h>mless--b v active4 ,! game-pres]ve is neat & attractive1 be+ pr9t$ 9 colors1 & ! birds & animals are well wor? hunt+4 ,ea* has a fix$ value--& "s ( !m mu/ n be %ot at all--s !re is ample opportunity = a display ( skill 9 br++ d[n ^? :i* c\nt mo/4 ,electric bullets are actually %ot f ! electric gun by electricity4 ,?is in/ructive game w furni% a va/ am\nt ( amusem5t to all4 ,! ,game-,pres]ve1--! ,electric ,gun1--! ,%oot+-,box1--! ,electric ,bullets1--9 fact1 ! entire electrical outfit1 toge!r ) complete illu/rat$ directions1 w be s5t 9 a neat box1 ,po/-,paid1 ^u receipt ( #ej c5ts1 by ,,?omas ,m4 ,,/4 ,,john1 #hdh ,n9? ,ave41 ,new ,york 99 99 99 99 99 ,transcrib]'s note3 ,obvi\s punctuation errors 7 correct$4 ,page #df1 turnnd *ang$ to turn$ 7be turn$ to #a7 ,page #ff1 ^w a add$ to text 79 a glass j>7