,,! ,,/ory ,,( ,,electricity ,,by ,,john ,,munro ,,au?or ,,( ,,electricity ,,& ,,its ,,uses1 ,,pione]s ,,( ,,electricity1 ,,h]oes ,,( ,,! ,,telegraph1 ,,etc41 ,,& ,,jo9t ,,au?or ,,( ,,munro ,,& ,,jamieson',s ,,pocket-,,book ,,( ,,electrical ,,rules ,,& ,,tables ,,preface4 ,a "w on electricity ne$s little recomm5dation to /imulate ! int]e/ ( ! g5]al read]4 ,electricity 9 its manifold applications is s l>ge a factor 9 ! com=t & conv5i5ce ( our daily life1 s ess5tial to ! indu/rial organization :i* embraces e dwell] 9 a civiliz$ l&1 s important 9 ! developm5t & ext5sion ( civilization itself1 t a k ( its pr9ciples & ! means ?r\gh :i* !y are direct$ to ! s]vice ( mank9d %\ld be a "p ( ! m5tal equipm5t ( ev]yone :o pret5ds to education 9 its true/ s5se4 ,let anyone /op to consid] h[ he individually w\ld be affect$ if all electrical s]vice 7 sudd5ly to cease1 & he _c fail to appreciate ! claims ( electricity to att5tive /udy4 ,! purpose ( ?is little book is to pres5t ! ess5tial facts ( electrical sci5ce 9 a popul> & int]e/+ way1 z befits ! s*eme ( ! s]ies to :i* x belongs4 ,electrical ph5om5a h be5 obs]v$ s9ce ! fir/ man view$ "o ( ! mo/ spectacul> & magnific5t ( !m all 9 ! ?und]/orm1 b ! s]vices ( electricity :i* we enjoy are ! product solely ( sci5tific a*ievem5t 9 ! n9ete5? c5tury4 ,x is to ^! s]vices t ! ma9 "p ( ! foll[+ discussion is devot$4 ,! introductory *apt]s deal ) v>i\s s\rces ( electrical en]gy1 9 friction1 *emical action1 heat & magnetism4 ,! re/ ( ! book describes ! applications ( electricity 9 electroplat+1 communication by telegraph1 telephone1 & wireless telegraphy1 ! production ( light & heat1 ! transmission ( p[]1 transportation ov] rails & 9 vehicles1 & ! multitude ( o!r uses4 ,july1 #aiae4 ,,publi%]s' ,,note4 ,= our edition ( ?is "w ! t]m9ology has be5 alt]$ to con=m ) ,am]ican usage1 "s new matt] has be5 add$1 & a few ( ! cuts h be5 *ang$ & "s new ones introduc$1 9 ord] to adapt ! book fully to ! practical requirem5ts ( ,am]ican read]s4 ,,cont5ts4 ,i4 ,,! ,,electricity ,,( ,,friction ,,ii4 ,,! ,,electricity ,,( ,,*emi/ry ,,iii4 ,,! ,,electricity ,,( ,,heat ,,iv4 ,,! ,,electricity ,,( ,,magnetism ,v4 ,,electrolysis ,,vi4 ,,! ,,telegraph ,,& ,,telephone ,,vii4 ,,electric ,,light ,,& ,,heat ,,viii4 ,,electric ,,p[] ,,ix4 ,,m9or ,,uses ,,( ,,electricity ,x4 ,,! ,,wireless ,,telegraph ,,xi4 ,,electro-,,*emi/ry ,,& ,,electro-,,metallurgy ,,xii4 ,,electric ,,railways ,,app5dix ,,! ,,/ory ,,( ,,electricity4 ,,*apt] ,i4 ,,! ,,electricity ,,( ,,friction4 ,a s*oolboy :o rubs a /ick ( seal+-wax on ! sleeve ( 8 jacket1 !n holds x ov] du/y %r$s or bits ( /raw to see !m fly up & cl+ to ! wax1 repeats )\t kn[+ x ! fundam5tal exp]im5t ( electricity4 ,9 rubb+ ! wax on 8 coat he has electrifi$ x1 & ! dry du/ or bits ( wool are attract$ to x by reason ( a my/]i\s process :i* is call$ induction4 ,electricity1 l fire1 0 probably discov]$ by "s primeval savage4 ,accord+ to ,humboldt1 ! ,indians ( ! ,or9oco sometimes amuse !mselves by rubb+ c]ta9 beans to make !m attract wisps ( ! wild cotton1 & ! cu/om is d\btless v old4 ,c]ta9ly ! anci5t ,greeks knew t a piece ( amb] _h :5 rubb$ ! prop]ty ( attract+ light bodies4 ,?ales ( ,miletus1 wise/ ( ! ,sev5 ,sages1 & fa!r ( ,greek philosophy1 expla9$ ?is curi\s effect by ! pres5ce ( a s\l 9 ! amb]1 :atev] he meant by t4 ,?ales fl\ri%$ #fjj ye>s be=e ! ,*ri/ian era1 :ile ,croesus reign$ 9 ,lydia1 & ,cyrus ! ,great1 9 ,p]sia1 :5 ! r5[n$ ,solon gave 8 laws to ,a!ns1 & ,necos1 ,k+ ( ,egypt1 made w> on ,josiah1 ,k+ ( ,judah1 & aft] defeat+ him at ,megiddo1 d$icat$ ! corslet he _h worn dur+ ! battle to ,apollo ,didymaeus 9 ! temple ( ,bran*idas1 ne> ,miletus4 ,amb]1 ! fossil res9 ( a p9e tree1 0 f\nd 9 ,sicily1 ! %ores ( ! ,baltic1 & o!r p>ts ( ,europe4 ,x 0 a preci\s /one !n z n[1 & an article ( trade ) ! ,pho5icians1 ^? e>ly m]*ants ( ! ,m$it]ranean4 ,! attractive p[] might enhance ! value ( ! gem 9 ! eyes ( ! sup]/iti\s anci5ts1 b !y d n seem to h inve/igat$ x1 & beyond ! speculation ( ,?ales1 !y h told u no?+ m ab\t x4 ,t[>ds ! end ( ! sixte5? c5tury ,dr4 ,gilb]t ( ,col*e/]1 physician to ,que5 ,elizabe?1 made ?is prop]ty ! subject ( exp]im5t1 & %[$ t1 f> f be+ peculi> to amb]1 x 0 possess$ by sulphur1 wax1 glass1 & _m o!r bodies :i* he call$ electrics1 f ! ,greek ^w elektron1 signify+ amb]4 ,?is great discov]y 0 ! />t+-po9t ( ! mod]n sci5ce ( electricity4 ,t feeble & my/]i\s =ce :i* _h be5 ! wond] ( ! simple & ! amusem5t ( ! va9 c\ld n be slight$ any long] z a curi\s freak ( nature1 b assur$ly none dreamt t a day 0 dawn+ 9 :i* x w\ld trans=m ! _w4 ,otto von ,gu]icke1 burgoma/] ( ,magdeburg1 0 ! fir/ to inv5t a ma*9e = excit+ ! electric p[] 9 l>g] quantities by simply turn+ a ball ( sulphur betwe5 ! b>e h&s4 ,improv$ by ,sir ,isaac ,newton & o!rs1 :o employ$ glass rubb$ ) silk1 x creat$ sp>ks sev]al in*es long4 ,! ord9>y frictional ma*9e z n[ made is illu/rat$ 9 figure i1 :]e ,p is a disc ( plate glass m\nt$ on a sp9dle & turn$ by h&4 ,rubb]s ( silk ,r1 sme>$ ) an amalgam ( m]cury & t91 to increase _! effici5cy1 press ! rim ( ! plate betwe5 !m z x revolves1 & a brass conductor ,c1 insulat$ on glass po/s1 is fitt$ ) po9ts l ! tee? ( a comb1 :i*1 z ! electrifi$ surface ( ! plate passes by1 collect ! electricity & *>ge ! conductor ) positive electricity4 ,ma*9es ( ?is sort h be5 made ) plates #g feet 9 diamet]1 & yield+ sp>ks ne>ly #b feet long4 ,! prop]ties ( ! electric fire1 z x 0 n[ call$1 7 *iefly inve/igat$ by ,dufay4 ,to ref9e on ! primitive exp]im5t let u replace ! %r$s by a pi?ball hung f a support by a silk ?read1 z 9 figure #b4 ,if we rub ! glass rod vigor\sly ) a silk h&k]*ief & hold x ne>1 ! ball w fly t[>d ! rod4 ,simil>ly we may rub a /ick ( seal+ wax1 a b> ( sulphur1 inde$1 a great v>iety ( sub/ances1 & by ?is easy te/ we %all f9d !m electrifi$4 ,glass rubb$ ) glass w n %[ any sign ( electrification1 nor w wax rubb$ on wax2 b :5 ! rubb] is ( a diff]5t mat]ial to ! ?+ rubb$1 we %all f9d1 on us+ prop] precautions1 t electricity is develop$4 ,9 fact1 ! prop]ty :i* 0 once ?\ght peculi> to amb] is f\nd to belong to all bodies4 ,,any ,,sub/ance1 ,,:5 ,,rubb$ ,,) ,a ,,diff]5t ,,sub/ance1 ,,becomes ,,electrifi$4 ,! electricity ?us produc$ is t]m$ frictional electricity4 ,( c\rse !re are "s mat]ials1 su* z amb]1 glass1 & wax1 :i* display ! effect mu* bett] ?an o!rs1 & h5ce its orig9al discov]y4 ,9 dry fro/y wea!r ! friction ( a tortoise-%ell comb w electrify ! hair & make x cl+ to ! tee?4 ,sometimes p]sons emit sp>ks 9 pull+ (f _! flannels or silk /ock+s4 ,! fur ( a cat1 or ev5 ( a g>m5t1 /rok$ 9 ! d>k ) a w>m dry h& w be se5 to gl[1 & p]haps he>d to crackle4 ,dur+ w9t] a p]son c electrify himself by %uffl+ 9 8 slipp]s ov] ! c>pet1 & light ! gas ) a sp>k f 8 f+]4 ,glass & seal+-wax are1 h[ev]1 ! mo/ conv5i5t means = inve/igat+ ! electricity ( friction4 ,a glass rod :5 rubb$ ) a silk h&k]*ief becomes1 z we h se51 highly electric1 & w attract a pi?ball 7fig4 #b74 ,moreov]1 if we sub/itute ! h&k]*ief = ! rod x w also attract ! ball 7fig4 #c74 ,cle>ly1 !n1 ! h&k]*ief :i* rubb$ ! rod z well z ! rod itself is electrifi$4 ,at fir/ we might suppose t ! h&k]*ief _h m]ely rubb$ (f "s ( ! electricity f ! rod1 b a little inve/igation w soon %[ t is n ! case4 ,if we all[ ! pi?ball to t\* ! glass rod x w /eal "s ( ! electricity on ! rod1 & we %all n[ f9d ! ball ,,repell$ by ! rod1 z illu/rat$ 9 figure #d4 ,!n1 if we )draw ! rod & br+ =w>d ! h&k]*ief1 we %all f9d ! ball ,,attract$ by x4 ,evid5tly1 !re=e1 ! electricity ( ! h&k]*ief is ( a diff]5t k9d f t ( ! rod4 ,aga91 if we all[ ! ball to t\* ! h&k]*ief & rub (f "s ( its electricity1 ! ball w be ,,repell$ by ! h&k]*ief & ,,attract$ by ! rod4 ,?us we arrive at ! conclusion t :]eas ! glass rod is *>g$ ) "o k9d ( electricity1 ! h&k]*ief :i* rubb$ x is *>g$ ) ano!r k9d1 &1 judg+ by _! contr>y effects on ! *>g$ ball or indicator1 !y are ( opposite k9ds4 ,to di/+ui% ! two sorts1 "o is call$ ,,positive & ! o!r ,,negative electricity4 ,fur!r exp]im5ts ) o!r sub/ances w %[ t sometimes ! rod is negative :ile ! rubb] is positive4 ,?us1 if we rub ! glass rod ) cat's fur in/ead ( silk1 we %all f9d ! glass negative & ! fur positive4 ,aga91 if we rub a /ick ( seal+-wax ) ! silk h&k]*ief1 we %all f9d ! wax negative & ! silk positive4 ,b 9 e case "o is ! opposite ( ! o!r1 & moreov]1 an equal quantity ( bo? sorts ( electricity is develop$1 "o k9d on ! rod & ! o!r on ! rubb]4 ,h5ce we conclude t ,,equal ,,& ,,opposite ,,quantities ,,( ,,electricity ,,are ,,simultane\sly ,,develop$ ,,by ,,friction4 ,if any two ( ! foll[+ mat]ials be rubb$ toge!r1 t high] 9 ! li/ becomes positively & ! o!r negatively electrifi$3-- ,,positive 774 ,cats' fur4 ,poli%$ glass4 ,wool4 ,cork1 at ord9>y temp]ature4 ,co>se br[n pap]4 ,cork1 heat$4 ,:ite silk4 ,black silk4 ,%ellac4 ,r\gh glass4 ,,negative 7-74 ,! li/ %[s t quality1 z well z k9d1 ( mat]ial affects ! production ( electricity4 ,?us poli%$ glass :5 rubb$ ) silk is positive1 :]eas r\gh glass is negative4 ,cork at ord9>y temp]ature is positive :5 rubb$ ) hot cork4 ,black silk is negative to :ite silk1 & x has be5 obs]v$ t ! be/ radiator & absorb] ( light & heat is ! mo/ negative4 ,black clo?1 = in/ance1 is a bett] radiator ?an :ite1 h5ce 9 ! ,arctic regions1 :]e ! body is mu* w>m] ?an ! surr\nd+ air1 _m wild animals get a :ite coat 9 w9t]1 & 9 ! tropics1 :]e ! sun%9e is hott] ?an ! body1 ! ,european dons a :ite suit4 ,! exp]im5ts ( figures #a1 #b1 & #c h also %[n u t :5 ! pi?ball is *>g$ ) ! positive electricity ( ! glass rod x is ,,repell$ by ! l *>ge ^u ! rod1 & ,,attract$ by ! negative or unlike *>ge on ! h&k]*ief4 ,aga91 :5 x is *>g$ ) ! negative electricity ( ! h&k]*ief x is ,,repell$ by ! l *>ge on ! h&k]*ief & ,,attract$ by ! positive or unlike *>ge on ! rod4 ,!re=e x is usual to say t ,,l ,,electricities ,,repel ,,& ,,unlike ,,electricities ,,attract ,,ea* ,,o!r4 ,we h said t all bodies yield electricity "u ! friction ( dissimil> bodies2 b ?is _c be prov$ = e body by simply hold+ x 9 "o h& & rubb+ x ) ! excitor1 z may be done 9 ! case ( glass4 ,= in/ance1 if we take a brass rod 9 ! h& & apply ! rubb] vigor\sly1 x w fail to attract ! pi?ball1 = !re is no trace ( electricity ^u x4 ,?is is because ! metal diff]s f ! glass 9 ano!r electrical prop]ty1 & !y mu/ !re=e be diff]5tly treat$4 ,brass1 9 fact1 is a conductor ( electricity & glass is n4 ,9 o!r words1 electricity is conduct$ or l$ away by brass1 s t1 z soon z x is g5]at$ by ! friction1 x fl[s ?r\gh ! h& & body ( ! exp]im5t]1 :i* are also conductors1 & is lo/ 9 ! gr\nd4 ,glass on ! o!r h&1 is an ,,insulator1 & ! electricity rema9s on ! surface ( x4 ,if1 h[ev]1 we atta* a glass h&le to ! rod & hold x by t :il/ rubb+ x1 ! electricity _c !n escape to ! e>?1 & ! brass rod w attract ! pi?-ball4 ,all bodies are conductors ( electricity 9 "s degree1 b !y v>y s enorm\sly 9 ?is respect t x has be5 f\nd conv5i5t to divide !m into two extreme classes--conductors & insulators4 ,^! run into ea* o!r ?r\gh an int]m$iate gr\p1 :i* are nei!r good conductors nor good insulators4 ,! foll[+ are ! *ief examples ( ^! classes3-- ,,conductors4--,all ! metals1 c>bon4 ,,int]m$iate 7bad conductors & bad insulators74--,wat]1 aque\s solutions1 moi/ bodies2 wood1 cotton1 hemp1 & pap] 9 any b a dry atmosph]e2 liquid acids1 r>efi$ gases4 ,,insulators4--,p>aff9 7solid or liquid71 ozok]it1 turp5t9e1 silk1 res91 seal+-wax or %ellac1 india-rubb]1 gutta-p]*a1 ebonite1 ivory1 dry wood1 dry glass or porcela91 mica1 ice1 air at ord9>y pressures4 ,x is rem>kable t ! be/ conductors ( electricity1 t is to say1 ! sub/ances :i* (f] lea/ resi/ance to its passage1 = in/ance ! metals1 are also ! be/ conductors ( heat1 & t insulators made r$ hot become conductors4 ,air is an excell5t insulator1 & h5ce we are able to p]=m our exp]im5ts on frictional electricity 9 x4 ,we c also run b>e telegraph wires ?r\gh x1 by tak+ c>e to insulate !m ) glass or porcela9 f ! wood5 poles :i* support !m above ! gr\nd4 ,wat]1 on ! o!r h&1 is a p>tial conductor1 & a great enemy to ! /orage or conveyance ( electricity1 f its habit ( soak+ into por\s metals1 or deposit+ 9 a film ( dew on ! cold surfaces ( insulators su* z glass1 porcela91 or ebonite4 ,! rem$y is to exclude x1 or keep ! insulators w>m & dry1 or coat !m ) %ellac v>ni%1 wax1 or p>aff94 ,subm>9e telegraph wires runn+ "u ! sea are usually insulat$ f ! surr\nd+ wat] by india-rubb] or gutta-p]*a4 ,! di/9ction betwe5 conductors & non-conductors or insulators 0 fir/ obs]v$ by ,/eph5 ,gray1 a p5sion] ( ! ,*>t]-h\se4 ,gray actually transmitt$ a *>ge ( electricity along a pack-?read insulat$ ) silk1 to a di/ance ( sev]al hundr$ y>ds1 & ?us took an important /ep 9 ! direction ( ! electric telegraph4 ,x has s9ce be5 f\nd t ,,frictional ,,electricity ,,appe>s ,,only ,,on ,,! ,,ext]nal ,,surface ,,( ,,conductors4 ,?is is well %[n by a device ( ,f>aday resembl+ a small butt]fly net insulat$ by a glass h&le 7fig4 #e74 ,if ! net be *>g$ x is f\nd t ! electrification is only outside1 & if x be sudd5ly drawn outside 91 z %[n by ! dott$ l9e1 ! electrification is /ill f\nd outside1 prov+ t ! *>ge has %ift$ f ! inn] to ! out] surface4 ,9 ! same way if a holl[ conductor is *>g$ ) electricity1 none is discov]able 9 ! int]ior4 ,moreov]1 its di/ribution on ! ext]ior is influ5c$ by ! %ape ( ! out] surface4 ,on a sph]e or ball x is ev5ly di/ribut$ all r\nd1 b x accumulates on %>p edges or corn]s1 & mo/ ( all on po9ts1 f :i* x is easily dis*>g$4 ,a neutral body c1 z we h se5 7fig4 #d71 be *>g$ by ,,contact ) an electrifi$ body3 b x c also be *>g$ by ,,induction1 or ! influ5ce ( ! electrifi$ body at a di/ance4 ,?us if we electrify a glass rod positively 77 & br+ x ne> a neutral or unelectrifi$ brass ball1 insulat$ on a glass support1 z 9 figure #f1 we %all f9d ! side ( ! ball next ! rod no long] neutral b negatively electrifi$ 7-71 & ! side away f ! rod positively electrifi$ 774 ,if we take away ! rod aga9 ! ball w return to its neutral or non-electric /ate1 %[+ t ! *>ge 0 tempor>ily induc$ by ! pres5ce ( ! electrifi$ rod4 ,aga91 if1 z 9 figure #g1 we h two insulat$ balls t\*+ ea* o!r1 & br+ ! rod up1 t ne>e/ ! rod w become negative & t f>!/ f x positive4 ,x appe>s f ^! facts t electricity has ! p[] ( di/urb+ or decompos+ ! neutral /ate ( a neighb\r+ conductor1 & attract+ ! unlike :ile x repels ! l induc$ *>ge4 ,h5ce1 too1 x is t ! electrifi$ amb] or seal+-wax is able to attract a light /raw or pi?ball4 ,! effect supplies a simple way ( develop+ a l>ge am\nt ( electricity f a small initial *>ge4 ,= if 9 figure #f ! positive side ( ! ball be connect$ = a mom5t to e>? by a conductor1 its positive *>ge w escape1 leav+ ! negative on ! ball1 & z !re is no long] an equal positive *>ge to recomb9e ) x :5 ! excit+ rod is )drawn1 x rema9s z a negative *>ge on ! ball4 ,simil>ly1 if we sep>ate ! two balls 9 figure #g1 we ga9 two equal *>ges--"o positive1 ! o!r negative4 ,^! processes h only to be repeat$ by a ma*9e 9 ord] to develop v /rong *>ges f a feeble s\rce4 ,f>aday saw t ! int]v5+ air play$ a "p 9 ?is action at a di/ance1 & prov$ conclusively t ! value ( ! induction dep5d$ on ! nature ( ! m$ium betwe5 ! induc$ & ! induc+ *>ge4 ,he %[$1 = example1 t ! induction ?r\gh an int]v5+ cake ( sulphur is great] ?an ?r\gh an equal ?ickness ( air4 ,?is prop]ty ( ! m$ium is t]m$ its ,,inductive ,,capacity4 ,! ,electrophorus1 or c>ri] ( electricity1 is a simple device = develop+ & convey+ a *>ge on ! pr9ciple ( induction4 ,x consi/s1 z %[n 9 figure #h1 ( a metal plate ,b hav+ an insulat+ h&le ( glass ,h1 & a flat cake ( res9 or ebonite ,r4 ,if ! res9 is laid on a table & briskly rubb$ ) cat's fur x becomes negatively electrifi$4 ,! brass plate is !n lift$ by ! h&le & laid ^u ! cake4 ,x t\*es ! electrifi$ surface at a few po9ts1 takes a m9ute *>ge f ^! by contact4 ,! re/ ( x1 h[ev]1 is insulat$ f ! res9 by ! air4 ,9 ! ma91 !re=e1 ! negative *>ge ( ! res9 is free to induce an opposite or positive *>ge on ! l[] surface & a negative *>ge on ! upp] surface ( ! plate4 ,by t\*+ ?is upp] surface ) ! f+]1 z %[n 9 figure #h1 ! negative *>ge w escape ?r\gh ! body to ! gr\nd or e>?1 z x is te*nically call$1 & ! positive *>ge w rema9 on ! plate4 ,we c )draw x by lift+ ! plate1 & prove its exi/5ce by draw+ a sp>k f x ) ! knuckle4 ,! process c be repeat$ z long z ! negative *>ge cont9ues on ! res94 ,^! t9y sp>ks f ! electrophorus1 or ! bigg] dis*>ges ( an electrical ma*9e1 c be /or$ 9 a simple app>atus call$ a ,leyd5 j>1 :i* 0 discov]$ by accid5t4 ,"o day ,cuneus1 a pupil ( ,mus*5broeck1 pr(essor 9 ! ,univ]sity ( ,leyd51 0 try+ to *>ge "s wat] 9 a glass bottle by connect+ x ) a *a9 to ! sp>kl+ knob ( an electrical ma*9e4 ,hold+ ! bottle 9 "o h&1 he undid ! *a9 ) ! o!r1 & receiv$ a viol5t %ock :i* ca/ ! bottle on ! floor4 ,mus*5broeck1 eag] to v]ify ! ph5om5on1 repeat$ ! exp]im5t1 ) a /ill m lively & conv9c+ result4 ,84 n]ves 7 %ak5 = two days1 & he aft]w>ds prote/$ t he w\ld n suff] ano!r %ock = ! :ole k+dom ( ,france4 ,! ,leyd5 j> is illu/rat$ 9 figure #i1 & consi/s 9 g5]al ( a glass bottle p>tly coat$ inside & out ) t9foil ,f1 & hav+ a brass knob ,k connect+ ) its int]nal coat4 ,:5 ! *>g$ plate or conductor ( ! electrophorus t\*es ! knob ! inn] foil takes a positive *>ge1 :i* induces a negative *>ge 9 ! out] foil ?r\gh ! glass4 ,! correspond+ positive *>ge induc$ at ! same "t escapes ?r\gh ! h& to ! gr\nd or e>?4 ,! inn] coat+ is n[ positively & ! out] coat+ negatively electrifi$1 & ^! two opposite *>ges b9d or hold ea* o!r by mutual attraction4 ,! bottle w !re=e cont9ue *>g$ = a long "t2 9 %ort1 until x is purposely dis*>g$ or ! two electricities comb9e by leakage ov] ! surface ( ! glass4 ,to dis*>ge ! j> we ne$ only connect ! two foils by a conductor1 & ?us all[ ! sep>at$ *>ges to comb9e4 ,?is %\ld be done by jo9+ ! ,,out] to ! ,,inn] coat ) a /\t wire1 or1 bett] /ill1 ! dis*>g+ tongs ,t1 z %[n 9 ! figure4 ,o!rwise1 if ! tongs are fir/ appli$ to ! inn] coat1 ! op]ator w receive ! *>ge ?r\gh 8 arms & *e/ 9 ! mann] ( ,cuneus & ,mus*5broeck4 ,leyd5 j>s c be connect$ toge!r 9 batt]ies1 s z to give v p[]ful effects4 ,"o me?od is to jo9 ! inn] coat ( "o to ! out] coat ( ! next4 ,?is is kn[n z connect+ 9 s]ies1 & gives a v long sp>k4 ,ano!r me?od is to jo9 ! inn] coat ( "o to ! inn] coat ( ! next1 & simil>ly all ! out] coats toge!r4 ,?is is call$ connect+ 9 p>allel1 or quantity1 & gives a big1 b n a long sp>k4 ,( late ye>s ! pr9ciple ( induction1 :i* is ! secret ( ! ,leyd5 j> & electrophorus1 has be5 appli$ 9 con/ruct+ influ5ce ma*9es = g5]at+ electricity4 ,p]haps ! mo/ effective ( ^! is ! ,wim%ur/1 :i* we illu/rate 9 figure #aj1 :]e ,,pp are two circul> glass plates :i* rotate 9 opposite directions on turn+ ! h&le4 ,on ! out] rim ( ea* is cem5t$ a r[ ( radial slips ( metal at equal int]vals4 ,! slips at opposite ends ( a diamet] are connect$ toge!r twice dur+ ea* revolution ( ! plates by wire bru%es ,s1 & collect+ combs ,,tt s]ve to *>ge ! positive & negative conductors ,,cc1 :i* yield v p[]ful sp>ks at ! knobs ,k above4 ,! giv5 !ory ( ?is ma*9e may be op5 to "q1 b !re c be no d\bt ( its wond]ful p]=mance4 ,a small "o produces a viol5t sp>k #h or #aj in*es long aft] a few turns ( ! h&le4 ,! electricity ( friction is s unmanageable t x has n be5 appli$ 9 practice to any great ext5t4 ,9 #agec ,mr4 ,*>les ,morrison1 ( ,gre5ock1 publi%$ ! fir/ plan ( an electric telegraph 9 ! ,scots ,magaz9e1 & propos$ to *>ge an insulat$ wire at ! ne> end s z to make x attract pr9t$ lett]s ( ! alphabet at ! f> end4 ,sir ,francis ,ronalds also inv5t$ a telegraph actuat$ by ?is k9d ( electricity1 b nei!r ( ^! came into use4 ,morrison1 an obscure g5ius1 0 be=e 8 age1 & ,ronalds 0 politely in=m$ by ! ,gov]nm5t ( 8 day t telegraphs ( any k9d 7 :olly unnecess>y4 ,little in/rum5ts = light+ gas by means ( ! sp>k are1 h[ev]1 made1 & ! noxi\s fumes ( *emical & lead works are cond5s$ & laid by ! dis*>ge f ! ,wim%ur/ ma*9e4 ,! electricity %$ 9 ! air causes ! du/ & smoke to adh]e by induction & settle 9 flakes ^u ! sides ( ! flues4 ,p]haps ! old rem>k t smuts or blacks fall+ to ! gr\nd on a sultry day are a sign ( ?und] is traceable to a simil> action4 ,! mo/ important practical result ( ! e>ly exp]im5ts ) frictional electricity 0 ,b5jam9 ,frankl9's great discov]y ( ! id5tity ( lightn+ & ! electric sp>k4 ,"o day 9 ,june1 #agib1 he w5t to ! common at ,philadelphia & flew a kite b5ea? a ?und]cl\d1 tak+ c>e to insulate 8 body f ! cord4 ,aft] a %[] _h wett$ ! /r+ & made x a conductor1 he 0 able to draw sp>ks f x ) a key & to *>ge a ,leyd5 j>4 ,! man :o _h robb$ ,jupit] ( 8 ?und]bolts became celebrat$ ?r\gh\t ! _w1 & lightn+ rods or conductors = ! protection ( life & prop]ty 7 soon br\ght out4 ,^!1 9 _! simple/ =m1 are tapes or /r&$ wires ( iron or copp] atta*$ to ! walls ( ! build+4 ,! l[] end ( ! conductor is sold]$ to a copp] plate buri$ 9 ! moi/ subsoil1 or1 if ! gr\nd is r dry1 9 a pit conta9+ coke4 ,sometimes x is m]ely sold]$ to ! wat] ma9s ( ! h\se4 ,! upp] end rises above ! highe/ *imney1 turret1 or spire ( ! edifice1 & bran*es into po9ts tipp$ ) incorrosive metal1 su* z plat9um4 ,x is usual to connect all ! outside metal ( ! h\se1 su* z ! gutt]s & f9ials to ! rod by means ( sold]$ jo9ts1 s z to =m "o cont9u\s metallic network or art]y = ! dis*>ge4 ,:5 a ?und]cl\d *>g$ ) electricity passes ov] ! gr\nd1 x induces a *>ge ( an opposite k9d ^u x4 ,! cl\d & e>? ) air betwe5 are analog\s to ! *>g$ foils ( ! ,leyd5 j> sep>at$ by ! glass4 ,! two electricities ( ! j>1 we "k1 attract ea* o!r1 & if ! insulat+ glass is too weak to hold !m asund]1 ! sp>k w pi]ce x4 ,simil>ly1 if ! insulat+ air _c resi/ ! attraction betwe5 ! ?und]cl\d & ! e>?1 x w be ruptur$ by a fla% ( lightn+4 ,! metal rod1 h[ev]1 t5ds to all[ ! two *>ges ( ! cl\d & e>? to comb9e quietly or to %unt ! dis*>ge pa/ ! h\se4 ,,*apt] ,,ii4 ,,! ,,electricity ,,( ,,*emi/ry4 ,a m tractable k9d ( electricity ?an t ( friction 0 discov]$ at ! beg9n+ ( ! pres5t c5tury4 ,! /ory goes t "s edible frogs 7 sk9n$ to make a s\p = ,madame ,galvani1 wife ( ! pr(essor ( anatomy 9 ! ,univ]sity ( ,bologna1 :o 0 9 delicate heal?4 ,z ! frogs 7 ly+ 9 ! laboratory ( ! pr(essor !y 7 obs]v$ to twit* ea* "t a sp>k 0 drawn f an electrical ma*9e t /ood by4 ,a simil> twit*+ 0 also notic$ :5 ! limbs 7 hung by copp] skew]s f an iron rail4 ,galvani ?\ght ! spasms 7 due to electricity 9 ! animal1 & produc$ !m at w by t\*+ ! n]ve ( a limb ) a rod ( z9c1 & ! muscle ) a rod ( copp] 9 contact ) ! z9c4 ,x 0 prov$1 h[ev]1 by ,alessanjra ,volta1 pr(essor ( physics 9 ! ,univ]sity ( ,pavia1 t ! electricity 0 n 9 ! animal b g5]at$ by ! contact ( ! two dissimil> metals & ! moi/ure ( ! fle%4 ,go+ a /ep fur!r1 9 ! ye> #ahjj he inv5t$ a new s\rce ( electricity on ?is pr9ciple1 :i* is kn[n z ,volta's pile4 ,x consi/s ( plates or discs ( z9c & copp] sep>at$ by a waf] ( clo? moi/5$ ) acidulat$ wat]4 ,:5 ! z9c & copp] are jo9$ ext]nally by a wire1 a ,,curr5t ( electricity is f\nd 9 ! wire ,"o pair ( plates ) ! liquid betwe5 makes a c\ple or elem5t2 & two or m1 built "o above ano!r 9 ! same ord] ( z9c1 copp]1 z9c1 copp]1 make ! pile4 ,! extreme z9c & copp] plates1 :5 jo9$ by a wire1 are f\nd to deliv] a curr5t4 ,?is =m ( ! voltaic1 or1 z x is sometimes call$1 galvanic batt]y1 has giv5 place to ! cell %[n 9 figure ,,ii1 :]e ! two plates ,z ,c are imm]s$ 9 acidulat$ wat] )9 ! vessel1 & connect$ outside by ! wire ,w4 ,! z9c plate has a positive & ! copp] a negative *>ge4 ,! positive curr5t fl[s f ! z9c to ! copp] inside ! cell & f ! copp] to ! z9c outside ! cell1 z %[n by ! arr[s4 ,x ?us makes a complete r\nd1 :i* is call$ ! voltaic circuit1 & if ! circuit is brok5 any:]e x w n fl[ at all4 ,! positive electricity ( ! z9c appe>s to trav]se ! liquid to ! copp]1 f :i* x fl[s ?r\gh ! wire to ! z9c4 ,! effect is t ! end ( ! wire atta*$ to ! copp] is positive 771 & call$ ! positive pole or electrode1 :ile ! end atta*$ to ! z9c is negative 7-71 & call$ ! negative pole or electrode4 ,a simple & easy way to avoid confusion z to ! direction ( ! curr5t1 is to rememb] t ! ,,positive curr5t fl[s ,,f ! ,,copp] ,,to ! ,,z9c at ! po9t ( ,,metallic contact4 ,! g5]ation ( ?is curr5t is accompani$ by *emical action 9 ! cell4 ,exp]im5t %[s t ! m]e ,,contact ( dissimil> mat]ials1 su* z copp] & z9c1 electrifies !m--z9c be+ positive & copp] negative2 b contact alone does n yield a cont9u\s curr5t ( electricity4 ,:5 we plunge ! two metals1 /ill 9 contact1 ei!r directly or ?r\gh a wire1 into wat] pref]ably acidulat$1 a *emical action is set up1 ! wat] is decompos$1 & ! z9c is consum$4 ,wat]1 z is well kn[n1 consi/s ( oxyg5 & hydrog54 ,! oxyg5 comb9es ) ! z9c to =m oxide ( z9c1 & ! hydrog5 is set free z gas at ! surface ( ! copp] plate4 ,s long z ?is process goes on1 t is to say1 z long z !re is z9c & wat] left1 we get an electric curr5t 9 ! circuit4 ,! exi/5ce ( su* a curr5t may be prov$ by a v simple exp]im5t4 ,place a p5ny above & a dime bel[ ! tip ( ! tongue1 !n br+ _! edges into contact1 & y w feel an acid ta/e 9 ! m\?4 ,figure #ab illu/rates ! suppos$ *emical action 9 ! cell4 ,on ! left h& are ! z9c & copp] plates 7,z ,c7 disconnect$ 9 ! liquid4 ,! atoms ( z9c are %[n by small circles2 ! molecules ( wat]1 t is1 oxyg51 & hydrog5 7,h#b,o7 by loz5ges ( unequal size4 ,on ! "r h& ! plates are connect$ by a wire outside ! cell2 ! curr5t />ts1 & ! *emical action beg9s4 ,an atom ( z9c unites ) an atom ( oxyg51 leav+ two atoms ( hydrog5 ?us set free to comb9e ) ano!r atom ( oxyg51 :i* 9 turn frees two atoms ( hydrog54 ,?is int]*ange ( atoms goes on until ! two atoms ( hydrog5 :i* are fre$ la/ abide on ! surface ( ! copp]4 ,! contact electricity ( ! z9c & copp] probably beg9s ! process1 & ! *emical action keeps x up4 ,oxyg51 be+ an electro-negative elem5t 9 *emi/ry1 is attract$ to ! z9c1 & hydrog51 be+ electro-positive1 is attract$ to ! copp]4 ,! diff]5ce ( electrical condition or pot5tial betwe5 ! plates by :i* ! curr5t is />t$ has be5 call$ ! electromotive =ce1 or =ce :i* puts ! electricity 9 motion4 ,! ob/ruction or h9drance :i* ! electricity ov]comes 9 pass+ ?r\gh its conductor is kn[n z ! ,,resi/ance4 ,obvi\sly ! high] ! electromotive =ce & ! l[] ! resi/ance1 ! /rong] w be ! curr5t 9 ! conductor4 ,h5ce x is desirable to h a cell :i* w give a high electromotive =ce & a l[ int]nal resi/ance4 ,voltaic cells are gr\p$ toge!r 9 ! mode ( ,leyd5 j>s4 ,figure #ac %[s h[ !y are jo9$ 9 s]ies1 ! z9c or negative pole ( "o be+ connect$ by wire to ! copp] or positive pole ( ! next4 ,?is arrangem5t multiplies alike ! electromotive =ce & ! resi/ance4 ,! electromotive =ce ( ! batt]y is ! sum ( ! electromotive =ces ( all ! cells1 & ! resi/ance ( ! batt]y is ! sum ( ! resi/ances ( all ! cells4 ,high electromotive =ces or pressures capable ( ov]com+ high resi/ances outside ! batt]y c be obta9$ 9 ?is way4 ,figure #ad %[s h[ ! z9cs are jo9$ 9 p>allel1 ! z9c or negative pole ( "o be+ connect$ by wire to ! z9c or negative pole ( ! re/1 & all ! copp] or positive poles toge!r4 ,?is arrangem5t does n increase ! electromotive =ce1 b dim9i%es ! resi/ance4 ,9 fact1 ! batt]y is equival5t to a s+le cell hav+ plates equal 9 area to ! total area ( all ! plates4 ,al?\gh unable to ov]come a high resi/ance1 x c produce a l>ge volume or quantity ( electricity4 ,num]\s voltaic comb9ations & v>ieties ( cell h be5 f\nd out4 ,9 g5]al1 :]e-ev] two metals 9 contact are plac$ 9 a liquid :i* acts ) m *emical en]gy on "o ?an on ! o!r1 z sulphuric acid does on z9c 9 pref]5ce to copp]1 !re is a developm5t ( electricity4 ,read]s may h se5 h[ an iron f5ce po/ corrodes at its junction ) ! lead t fixes x 9 ! /one4 ,?is decay is ow+ to ! wet =m+ a voltaic c\ple ) ! two dissimil> metals & ru/+ ! iron4 ,9 ! foll[+ li/ ( mat]ials1 :5 any two 9 contact are plung$ 9 dilute acid1 t :i* is high] 9 ! ord] becomes ! positive plate or negative pole to t :i* is l[]3-- ,,positive ,iron ,silv] ,z9c ,nickel ,gold ,cadmium ,bismu? ,plat9um ,t9 ,antimony ,graphite ,lead ,copp] ,,negative ,!re be+ no *emical union betwe5 ! hydrog5 & copp] 9 ! z9c & copp] c\ple1 t gas accumulates on ! surface ( ! copp] plate1 or is lib]at$ 9 bubbles4 ,n[1 hydrog5 is positive comp>$ ) copp]1 h5ce !y t5d to oppose ea* o!r 9 ! comb9ation4 ,! hydrog5 dim9i%es ! value ( ! copp]1 ! curr5t gr[s weak]1 & ! cell is said to pol>ise4 ,x foll[s t a simple wat] cell is n a good arrangem5t = ! supply ( a /eady curr5t4 ,! ,daniell cell is "o ( ! be/1 & gives a v con/ant curr5t4 ,9 ?is batt]y ! copp] plate is surr\nd$ by a solution ( sulphate ( copp] 7,cu ,,s#d71 :i* ! hydrog5 decomposes1 =m+ sulphuric acid 7,h#b,,s#d71 ?us tak+ itself out ( ! way1 & leav+ pure copp] 7,cu7 to be deposit$ z a fre% surface on ! copp] plate4 ,a fur!r improvem5t is made 9 ! cell by surr\nd+ ! z9c plate ) a solution ( sulphate ( z9c 7,zn ,,s#d71 :i* is a good conductor4 ,n[1 :5 ! oxide ( z9c is =m$ by ! oxyg5 unit+ ) ! z9c1 ! free sulphuric acid comb9es ) x1 =m+ m sulphate ( z9c1 & ma9ta9+ ! ,,conductivity ( ! cell4 ,x is only necess>y to keep up ! supply ( z9c1 wat]1 & sulphate ( copp] to procure a /eady curr5t ( electricity4 ,! ,daniell cell is con/ruct$ 9 v>i\s ways4 ,9 ! e>li] models ! two plates ) _! solutions 7 sep>at$ by a por\s j> or p>tition1 :i* all[$ ! solutions to meet )\t mix+1 & ! curr5t to pass4 ,sawdu/ moi/5$ ) ! solutions is sometimes us$ = ?is por\s sep>ator1 = in/ance1 on bo>d %ips = lay+ subm>9e cables1 :]e ! roll+ ( ! waves w\ld bl5d ! liquids4 ,9 ! gravity ,daniell ! solutions are kept ap>t by _! specific gravities1 yet m+le by sl[ diffusion4 ,figure #ae illu/rates ?is common type ( cell1 :]e ,z is ! z9c plate 9 a solution ( sulphate ( z9c1 & ,c is ! copp] plate 9 a solution ( sulphate ( copp]1 f$ by cry/als ( ! blue vitriol4 ,! wires to connect ! plates are %[n at ,,ww4 ,x %\ld be notic$ t ! z9c is ca/ l a :eel to expose a l>g] surface to oxidation1 & to r$uce ! resi/ance ( ! cell1 ?us increas+ ! yield ( curr5t4 ,! ext5t ( surface is n s important 9 ! case ( ! copp] plate1 :i* is n act$ on1 & 9 ?is case is m]ely a spiral ( wire1 help+ to keep ! solutions ap>t & ! cry/als d[n4 ,! ,daniell cell is mu* employ$ 9 telegraphy4 ,! ,buns5 cell consi/s ( a z9c plate 9 sulphuric acid1 & at c>bon plate 9 nitric acid1 ) a por\s sep>ator betwe5 ! liquids4 ,dur+ ! action ( ! cell1 hydrog51 :i* is lib]at$ at ! c>bon plate1 is remov$ by comb9+ ) ! nitric acid4 ,! ,grove cell is a modification ( ! ,buns51 ) plat9um in/ead ( c>bon4 ,! ,smee cell is a z9c plate side by side ) a plat9is$ silv] plate 9 dilute sulphuric acid4 ,! silv] is coat$ ) r\gh plat9um to increase ! surface & help to dislodge ! hydrog5 z bubbles & keep x f pol>is+ ! cell4 ,! ,buns51 ,grove1 & ,smee batt]ies are1 h[ev]1 m us$ 9 ! laboratory ?an else:]e4 ,! ,leclan*e is a fairly con/ant cell1 :i* requires little att5tion4 ,x pol>ises 9 action b soon rega9s its normal /r5g? :5 all[$ to re/1 & h5ce x is useful = work+ electric bells & telephones4 ,z %[n 9 figure #af1 x consi/s ( a z9c rod ) its connect+ wire ,z1 & a c>bon plate ,c ) its b9d+ screw1 betwe5 two cakes ,m ,m ( a mixture ( black oxide ( manganese1 sulphur1 & c>bon1 plung$ 9 a solution ( sal-ammoniac4 ,! oxide ( manganese relieves ! c>bon plate ( its hydrog54 ,! /r5g? ( ! solution is ma9ta9$ by sp>e cry/als ( sal-ammoniac ly+ on ! bottom ( ! cell1 :i* is clos$ to prev5t evaporation1 b has a v5?ole = ! escape ( gas4 ,! ,bi*romate ( ,pota% cell pol>ises m ?an ! ,leclan*e1 b yields a m p[]ful curr5t = a %ort "t4 ,x consi/s1 z %[n 9 figure #ag1 ( a z9c plate ,z betwe5 two c>bon plates ,c ,c imm]s$ 9 a solution ( bi*romate ( pota%1 sulphuric acid 7vitriol71 & wat]4 ,! z9c is always lift$ out ( ! solution :5 ! cell is n 9 use4 ,! gas :i* collects 9 ! c>bons1 & weak5s ! cell1 c be set free by rais+ ! plates out ( ! liquid :5 ! cell is n want$4 ,/irr+ ! solution has a simil> effect1 & sometimes ! con/ancy ( ! cell is ma9ta9$ by a circulation ( ! liquid4 ,9 ,full]'s bi*romate cell ! z9c is amalgamat$ ) m]cury1 :i* is kept 9 a pool beside x by means ( a por\s pot4 ,de la ,rue's *loride ( silv] cell 7fig4 #ah7 is1 f its con/ancy & small size1 well adapt$ = m$ical & te/+ purposes4 ,! plates are a little rod or p5cil ( z9c ,z1 & a /rip or wire ( silv] ,s1 coat$ ) *loride ( silv] & %ea!d 9 p>*m5t pap]4 ,!y are plung$ 9 a solution ( ammonium *loride ,a1 conta9$ 9 a glass phial or beak]1 :i* is clos$ to suppress evaporation4 ,a tray =m ( ! cell is also made by lay+ a %eet ( silv] foil on ! bottom ( ! %all[ j>1 & /rew+ x ) dry *loride ( silv]1 on :i* is laid a jelly to support ! z9c plate4 ,! jelly is prep>$ by mix+ a solution ( *loride ( ammonium ) ag>-ag>1 or ,ceylon moss4 ,?is type p]mits ! use ( l>g] plates1 & adapts ! batt]y = light+ small electric lamps4 ,skrivan(f has modifi$ ! ,de la ,rue cell by sub/itut+ a solution ( cau/ic pota% = ! ammonium *loride1 & 8 batt]y has be5 us$ = /> lights1 t is to say1 ! t9y electric lamps ( ! ballet4 ,! ,s*ans*ieff batt]y1 consi/+ ( z9c & c>bon plates 9 a solution ( basic sulphate ( m]cury1 is suitable = read+1 m9+1 & o!r portable lamps4 ,! ,latim] ,cl>k /&>d cell is us$ by electricians 9 te/+1 z a con/ant electromotive =ce4 ,x consi/s ( a pure z9c plate sep>at$ f a pool ( m]cury by a pa/e ( m]cur\s proto-sulphate & saturat$ solution ( sulphate ( z9c4 ,plat9um wires connect ) ! z9c & m]cury & =m ! poles ( ! batt]y1 & ! m\? ( ! glass cell is plugg$ ) solid p>aff94 ,z x is apt to pol>ise1 ! cell mu/ n be employ$ to yield a curr5t1 & o!rwise mu* c>e %\ld be tak5 ( x4 ,dry cells are m cleanly & portable ?an wet1 !y require little or no att5tion1 & are well suit$ = h\sehold or m$ical purposes4 ,! z9c plate =ms ! vessel conta9+ ! c>bon plate & *emical reag5ts4 ,figure #ai repres5ts a section ( ! ,e4 ,c4 ,c4 v>iety1 :]e ,z is ! z9c /&+ on an insulat+ sole ,i1 & fitt$ ) a connect+ wire or t]m9al ,t 7-71 :i* is ! negative pole4 ,! c>bon ,c is emb$d$ 9 black pa/e ,m1 *iefly compos$ ( manganese dioxide1 & has a b9d+ screw or t]m9al ,t 771 :i* is ! positive pole4 ,! black pa/e is surr\nd$ by a :ite pa/e ,z1 consi/+ ma9ly ( lime & sal-ammoniac4 ,!re is a lay] ( silicate cotton ,s ,c above ! pa/e1 & ! m\? is seal$ ) black pit* ,p1 ?r\gh :i* a wa/e-tube ,w ,t all[s ! gas to escape4 ,! ,helles5 dry cell is l ! ,e4 ,c4 ,c41 b conta9s a holl[ c>bon1 & is pack$ ) sawdu/ 9 a millbo>d case4 ,! ,leclan*e-,b>bi] dry cell is a modification ( ! ,leclan*e wet cell1 hav+ a pa/e ( sal-ammoniac in/ead ( a solution4 ,all ! =ego+ cells are call$ prim>y1 because !y are g5]ators ( electricity4 ,!re are1 h[ev]1 batt]ies kn[n z second>y1 :i* /ore ! curr5t z ! ,leyd5 j> /ores up ! dis*>ge f an electrical ma*9e4 ,9 ! action ( a prim>y cell1 z we h se51 wat] is split into its con/itu5t gases1 oxyg5 & hydrog54 ,moreov]1 x 0 discov]$ by ,c>lisle & ,ni*olson 9 ! ye> #ahjj t ! curr5t ( a batt]y c\ld decompose wat] 9 ! out] "p ( ! circuit4 ,_! exp]im5t is usually p]=m$ by !4 app>atus %[n 9 figure #bj1 :i* is t]m$ a voltamet]1 & consi/s ( a glass vessel ,v1 conta9+ wat] acidulat$ ) a little sulphuric acid to r5d] x a bett] conductor1 & two glass te/-tubes ,,oh inv]t$ ov] two plat9um /rips or electrodes1 :i* rise up f ! bottom ( ! vessel & are connect$ und]nea? x to wires f ! positive & negative poles ( ! batt]y ,c ,z4 ,x w be und]/ood t ! curr5t ent]s ! wat] by ! positive electrode1 & leaves x by ! negative electrode4 ,:5 ! p[] ( ! batt]y is suffici5t ! wat] 9 ! vessel is decompos$1 & oxyg5 be+ ! negative elem5t1 collects at ! positive foil or electrode1 :i* is cov]$ by ! tube ,o4 ,! hydrog51 on ! o!r h&1 be+ positive1 collects at ! negative foil "u ! tube ,h4 ,^! facts c be prov$ by dipp+ a r$-hot wick or tap] into ! gas ( ! tube ,o & see+ x blaze 9 pres5ce ( ! oxyg5 :i* fe$s ! combu/ion1 !n dipp+ ! light$ tap] into ! gas ( ! tube ,h & wat*+ x burn ) ! blue flame ( hydrog54 ,! volume ( gas at ! ,,ca?ode or negative electrode is always twice t at ! ,,anode or positive electrode1 z x %\ld be accord+ to ! kn[n composition ( wat]4 ,n[1 if we disconnect ! batt]y & jo9 ! two plat9um electrodes ( ! voltamet] by a wire1 we %all f9d a curr5t fl[+ out ( ! voltamet] z ?\gh x 7 a batt]y1 b 9 ! rev]se direction to ! orig9al curr5t :i* decompos$ ! wat]4 ,?is second>y or react+ curr5t is evid5tly due to ! pol>isation ( ! foils--t is to say1 ! electro- positive & electro-negative gases collect$ on !m4 ,pr(essor ,groves con/ruct$ a gas batt]y on ?is pr9ciple1 ! plates be+ ( plat9um & ! two gases surr\nd+ !m oxyg5 & hydrog51 b ! mo/ useful developm5t ( x is ! accumulator or /orage batt]y4 ,! fir/ practicable second>y batt]y ( ,ga/on ,plante 0 made ( %eet lead plates or electrodes1 kept ap>t by l95 clo? soak$ 9 dilute sulphuric acid1 aft] ! mann] ( ,volta's pile4 ,x 0 *>g$ by connect+ ! plates to a prim>y batt]y1 & p]oxide ( lead 7,pb,o#b7 0 =m$ on "o plate & spongy lead 7,pb7 on ! o!r4 ,:5 ! *>g+ curr5t 0 cut (f ! p]oxide plate became ! positive & ! spongy plate ! negative pole ( ! second>y cell4 ,faure improv$ ! ,plante cell by add+ a pa/e ( r$ lead or m9ium 7,pb#bjd7 & dilute sulphuric acid 7,h#b,,s#d71 by :i* a l>ge quantity ( p]oxide & spongy lead c\ld be =m$ on ! plates4 ,sellon & ,volckm> increas$ its effici5cy by putt+ ! pa/e into holes ca/ 9 ! lead4 ,! ,e4 ,p4 ,s4 accumulator ( ! ,electrical ,p[] ,/orage ,company is illu/rat$ 9 figure #ba1 & consi/s ( a glass or teak box conta9+ two sets ( lead5 grids p]=at$ ) holes1 :i* are prim$ ) ! pa/e & /eep$ 9 dilute sulphuric acid4 ,alt]nate grids are jo9$ to ! poles ( a *>g+ batt]y or g5]ator1 ^? connect$ to ! positive pole be+ conv]t$ into p]oxide ( lead & ! o!rs into spongy lead4 ,! t]m9al ( ! p]oxide plates1 be+ ! positive pole ( ! accumulator1 is pa9t$ r$1 & t ( ! spongy plates or negative pole black4 ,accumulators ( ?is k9d are highly useful z res]voirs ( electricity = ma9ta9+ ! electric light1 or work+ electric motors 9 tramc>s1 boats1 & o!r c>riages4 ,,*apt] ,,iii4 ,,! ,,electricity ,,( ,,heat4 ,9 ! ye> #ahba ,pr(essor ,seebeck1 ( ,b]l91 discov]$ a ?ird s\rce ( electricity4 ,volta _h f\nd t two dissimil> metals 9 contact w produce a curr5t by *emical action1 & ,seebeck %[$ t heat might take ! place ( *emical action4 ,?us1 if a b> ( antimony ,a 7fig4 #bb7 & a b> ( bismu? ,s are 9 contact at "o end1 & ! junction is heat$ by a _s lamp to a high] temp]ature ?an ! re/ ( ! b>s1 a diff]5ce 9 _! electric /ate or pot5tial w be set up1 & if ! o!r ends are jo9$ by a wire ,w1 a curr5t w fl[ ?r\gh ! wire4 ,! direction ( ! curr5t1 indicat$ by ! arr[1 is f ! bismu? to ! antimony across ! jo9t1 & f ! antimony to ! bismu? ?r\gh ! ext]nal wire4 ,?is comb9ation1 :i* is call$ a !rmo-electric c\ple1 is cle>ly analog\s to ! voltaic c\ple1 ) heat 9 place ( *emical aff9ity4 ,! direction ( ! curr5t )9 & )\t ! c\ple %[s t ! bismu? is positive to ! antimony4 ,?is prop]ty ( g5]at+ a curr5t ( electricity by contact "u ! influ5ce ( heat is n conf9$ to bismu? & antimony1 or ev5 to ! metals1 b is common to all dissimil> sub/ances 9 _! degree4 ,9 ! foll[+ li/ ( bodies ea* is positive to ^? b5ea? x1 negative to ^? above x1 & ! fur!r ap>t any two are 9 ! scale ! great] ! effect4 ,?us bismu? & antimony give a mu* /rong] curr5t ) ! same heat+ ?an copp] & iron4 ,bismu? & sel5ium produce ! be/ result1 b sel5ium is exp5sive & n easy to manipulate4 ,copp] & ,g]man silv] w make a *eap exp]im5tal c\ple3-- ,,positive ,bismu? ,cobalt ,potassium ,nickel ,sodium ,lead ,t9 ,copp] ,plat9um ,silv] ,z9c ,cadmium ,ars5ic ,iron ,r$ phosphorus ,antimony ,tellurium ,sel5ium ,,negative ,o!r ?+s be+ equal1 ! hott] ! jo9t 9 comp>ison ) ! free ends ( ! b>s ! /rong] ! curr5t ( electricity4 ,)9 c]ta9 limits ! curr5t is1 9 fact1 proportional to ?is diff]5ce ( temp]ature4 ,x always fl[s 9 ! same direction if ! jo9t is n ov]heat$1 or1 9 o!r words1 rais$ above a c]ta9 temp]ature4 ,! electromotive =ce & curr5t ( a !rmo-electric c\ple is v mu* small] ?an t giv5 by an ord9>y voltaic cell4 ,we c1 h[ev]1 multiply ! effect by connect+ a numb] ( pairs toge!r1 & s =m+ a pile or batt]y4 ,?us figure #bc %[s ?ree c\ples jo9$ 9 s]ies1 ! positive pole ( "o be+ connect$ to ! negative pole ( ! next4 ,n[1 if all ! junctions on ! left are hot & ^? on ! "r are cool1 we w get ! unit$ effect ( ! :ole1 & ! total curr5t w fl[ ?r\gh ! wire ,w1 jo9+ ! extreme b>s or positive & negative poles ( ! batt]y4 ,x mu/ be borne 9 m9d t al?\gh ! bismu? & antimony ( ?is !rmo-electric batt]y1 l ! z9c & copp] ( ! voltaic or *emico-electric batt]y1 are respectively positive & negative to ea* o!r1 ! poles or wires atta*$ to ^! metals are1 on ! contr>y1 negative & positive4 ,?is peculi>ity arises f ! curr5t />t+ betwe5 ! bismu? & antimony at ! heat$ junction4 ,! int]nal resi/ance ( a !rmo-electric pile is1 ( c\rse1 v slight1 ! metals be+ good conductors1 & ?is fact gives x a c]ta9 advantage ov] ! voltaic batt]y4 ,moreov]1 x is clean] & less tr\blesome ?an ! *emical batt]y1 = x is only necess>y to keep at ! requir$ diff]5ce ( temp]ature betwe5 ! hot & cold junctions 9 ord] to get a /eady curr5t4 ,no solutions or salts are requir$1 & !re appe>s to be little or no wa/e ( ! metals4 ,x is important1 h[ev]1 to avoid sudd5 heat+ & cool+ ( ! jo9ts1 z ?is t5ds to de/roy !m4 ,clammond1 ,gul*]1 & o!rs h con/ruct$ useful !rmo-piles = practical purposes4 ,figure #bd illu/rates a ,clammond !rmo- pile ( #ge c\ples or elem5ts4 ,! metals =m+ ^! pairs are an alloy ( bismu? & antimony = "o & iron = ! o!r4 ,prisms ( ! alloy are ca/ on /rips ( iron to =m ! junctions4 ,!y are b5t 9 r+s1 ! junctions 9 a s]ies mak+ a zig-zag r\nd ! circle4 ,! r+s are built "o ov] ! o!r 9 a cyl9d] ( c\ples1 & ! inn] junctions are heat$ by a ,buns5 gas-burn] 9 ! holl[ core ( ! batt]y4 ,a gas- pipe se5 9 front leads to ! burn]1 & ! wires ,,ww connect$ to ! extreme b>s or poles are ! electrodes ( ! pile4 ,!rmo-piles are int]e/+ f a sci5tific po9t ( view z a direct means ( trans=m+ heat into electricity4 ,a s5sitive pile is also a delicate detector ( heat by virtue ( ! curr5t set up1 :i* c be measur$ ) a galvanomet] or curr5t met]4 ,piles ( antimony & bismu? are made :i* c indicate ! heat ( a light$ mat* at a di/ance ( sev]al y>ds1 & ev5 ! radiation f c]ta9 ( ! />s4 ,!rmo-batt]ies h be5 us$ 9 ,france = work+ telegraphs1 & !y are capable ( supply+ small in/allations ( ! electric light or electric motors = dome/ic purposes4 ,! action ( ! !rmo-pile1 l t ( a voltaic cell1 c be rev]s$4 ,by s5d+ a curr5t ?r\gh ! c\ple f ! antimony to ! bismu? we %all f9d ! junction cool$4 ,?is ,pelti] effect1 z x is t]m$1 aft] its discov]]1 has be5 kn[n to freeze wat]1 b no practical application has be5 made ( x4 ,a v feeble !rmo-electric effect c be produc$ by heat+ ! junction ( two diff]5t pieces ( ! same sub/ance1 or ev5 by mak+ "o "p ( ! same conductor hott] ?an ano!r4 ,?us a s5sitive galvanomet] w %[ a weak curr5t if a copp] wire connect$ 9 circuit ) x be w>m$ at "o po9t4 ,moreov]1 x has be5 f\nd by ,"l ,kelv9 t if an iron wire is heat$ at any po9t1 & an electric curr5t be pass$ ?r\gh x1 ! hot po9t w %ift along ! wire 9 a direction contr>y to t ( ! curr5t4 ,,*apt] ,,iv4 ,,! ,,electricity ,,( ,,magnetism4 ,we h already se5 h[ electricity 0 fir/ produc$ by ! simple me?od ( rubb+ "o body on ano!r1 !n by ! less obvi\s means ( *emical union1 & next by ! f9] ag5cy ( heat4 ,9 all ^!1 x w be obs]v$1 a sub/antial contact is necess>y4 ,we h n[ to consid] a /ill m subtle process ( g5]ation1 n requir+ actual contact1 :i*1 z might be expect$1 0 discov]$ lat]1 t1 ma9ly ?r\gh ! m$ium ( magnetism4 ,! curi\s m9]al :i* has ! prop]ty ( attract+ iron 0 kn[n to ! ,*9ese sev]al ?\s& ye>s ago1 & c]ta9ly to ! ,greeks 9 ! times ( ,?ales1 :o1 z 9 ! case ( ! rubb$ amb]1 ascrib$ ! prop]ty to its possession ( a s\l4 ,lode/one1 a magnetic oxide ( iron 7,,fe#c,o#d71 is f\nd 9 v>i\s p>ts ( ,*9a1 especially at ,t'sz*\ 9 ,s\!rn ,*ihli1 :i* 0 =m]ly kn[n z ! ,city ( ! ,magnet4 ,x 0 call$ by ! ,*9ese ! love-/one or ?su-*y1 & ! /one t snat*es iron or ny-?y-*y1 & p]*ance its prop]ty ( po9t+ out ! nor? & s\? direction 0 discov]$ by dropp+ a light piece ( ! /one1 if n a sew+ ne$le made ( x1 on ! surface ( /ill wat]4 ,at all ev5ts1 we read 9 ,p]e ,du ,halde's ,description de la ,*9e1 t sometime 9 or ab\t ! ye> #bfce ,b4,c4 ! great ,emp]or ,hoang-ti1 hav+ lo/ 8 way 9 a fog :il/ pursu+ ! rebelli\s ,pr9ce ,t*iye\ on ! pla9s ( ,t*\-l\1 con/ruct$ a *>iot :i* %[$ ! c>d9al po9ts1 ?us enabl+ him to ov]take & put ! pr9ce to dea?4 ,a magnetic c> prec$$ ! ,emp]ors ( ,*9a 9 c]emonies ( /ate dur+ ! f\r? c5tury ( our era4 ,x conta9$ a g5ius 9 a fea!r dress :o po9t$ to ! s\?1 & 0 d\btless mov$ by a magnet float+ 9 wat] or turn+ on a pivot4 ,?is rude appliance 0 aft]w>ds ref9$ into ! ne$le compass = guid+ m>9]s on ! sea1 & assi/+ ! pr(essors ( f5g- %ui or geomancy 9 _! magic rites4 ,magnetite 0 also f\nd at ,h]aclea 9 ,lydia1 & at ,magnesium on ! ,me&] or ,magnesium at ,sipylos1 all 9 ,asia ,m9or4 ,x 0 call$ ! ,h]aclean ,/one by ! p1 b came at l5g? to be> ! "n ( ,magnet aft] ! city ( ,magnesia or ! my?ical %eph]d ,magnes1 :o 0 said to h discov]$ x by ! attraction ( 8 iron crook4 ,! anci5ts knew t x _h ! p[] ( communicat+ its attractive prop]ty to iron1 = we read 9 ,plato's ,ion t a numb] ( iron r+s c be support$ 9 a *a9 by ! ,h]aclean ,/one4 ,lucretius also describes an exp]im5t 9 :i* iron fil+s are made to rise up & rave 9 a brass bas9 by a magnet held und]nea?4 ,we are told by o!r writ]s t images ( ! gods & goddesses 7 susp5d$ 9 ! air by lode/one 9 ! ceil+s ( ! temples ( ,diana ( ,ephesus1 ( ,s]apis at ,alex&ria1 & o!rs4 ,x is surpris+1 h[ev]1 t nei!r ! ,greeks nor ,romans1 ) all _! philosophy1 w\ld seem to h discov]$ its directive prop]ty4 ,dur+ ! d>k ages pieces ( ,lode/one m\nt$ z magnets 7 employ$ 9 ! black arts4 ,a small natural magnet ( ?is k9d is %[n 9 figure #be1 :]e ,l is ! /one %od ) two iron pole-pieces1 :i* are jo9$ by a keep] ,a or sep>able bridge ( iron c>ry+ a hook = support+ weights4 ,app>5tly x 0 n until ! twelf? c5tury t ! compass f\nd its way into ,europe f ! ,ea/4 ,9 ! ,l&nammabok ( ,ari ,frode1 ! ,norse hi/orian1 we read t ,flocke ,vild]g]s51 a r5[n$ vik+1 sail$ f ,norway to discov] ,icel& 9 ! ye> #hfh1 & took ) him two rav5s z guides1 = 9 ^? days ! seam5 _h no lode/one 7t is1 no lid> /e91 or lead+ /one7 9 ! nor!rn c\ntries4 ,! ,bible1 a poem ( ,guiot de ,prov9s1 m9/rel at ! c\rt ( ,b>b>ossa1 :i* 0 writt5 9 or ab\t ! ye> #hij1 conta9s ! fir/ m5tion ( ! magnet 9 ! ,we/4 ,guiot relates h[ m>9]s h an art :i* _c deceive ( f9d+ ! position ( ! pole/>1 t does n move4 ,aft] t\*+ a ne$le ) ! magnet1 an ugly br[n /one :i* draws iron to itself1 he says !y put ! ne$le on a /raw & float x on wat] s t its po9t turns to ! hidd5 />1 & enables !m to keep _! c\rse4 ,arab trad]s _h probably borr[$ ! float+ ne$le f ! ,*9ese1 = ,bailak ,kibdjaki1 au?or ( ! ,m]*ant's ,treasure1 writt5 9 ! ?irte5? c5tury1 speaks ( its use 9 ! ,syrian sea4 ,! fir/ ,crusad]s 7 probably in/rum5tal 9 br++ x to ,france1 at all ev5ts ,jacobus de ,vitry 7#abjd-ae7 & ,v9c5t de ,beauvais 7#abej7 m5tion its use1 ,de ,beauvais call+ ! poles ( ! ne$le by ! ,arab words aphron & zohran4 ,ere long ! ne$le 0 m\nt$ on a pivot & provid$ ) a mov+ c>d %[+ ! pr9cipal directions4 ,! v>iation ( ! ne$le f ! true nor? & s\? 0 c]ta9ly kn[n 9 ,*9a dur+ ! twelf?1 & 9 ,europe dur+ ! ?irte5? c5tury4 ,columbus also f\nd t ! v>iation *ang$ its value z he sail$ t[>ds ,am]ica on 8 memorable voyage ( #adib4 ,moreov]1 9 #aegf1 ,norman1 a compass mak] 9 ,london1 %[$ t ! nor?- seek+ end ( ! ne$le dipp$ bel[ ! horizontal4 ,9 ^! e>ly days x 0 suppos$ t lode/one 9 ! pole- />1 t is to say1 ! lode/> ( ! poets or 9 m\nta9s ( ! f> nor?1 attract$ ! trembl+ ne$le2 b 9 ! ye> #afjj1 ,dr4 ,gilb]t1 ! f\nd] ( electric sci5ce1 demon/rat$ beyond a d\bt t ! :ole e>? 0 a great magnet4 ,a magnet1 z is well kn[n1 has1 l an electric batt]y1 always two poles or c5tres ( attraction1 :i* are situat$ ne> its extremities4 ,sometimes1 inde$1 :5 ! magnet is imp]fect1 !re are consequ5t poles ( weak] =ce betwe5 !m4 ,"o ( ! poles is call$ ! nor?1 & ! o!r ! s\?1 because if ! magnet 7 freely pivott$ l a compass ne$le1 ! =m] w\ld turn to ! nor? & ! latt] to ! s\?4 ,ei!r pole w attract iron1 b s(t or anneal$ iron does n reta9 ! magnetism ne>ly s well z /eel4 ,h5ce a boy's te/ = ! /eel ( 8 knife is only efficaci\s :5 ! blade itself becomes magnetic aft] be+ t\*$ ) ! magnet4 ,a piece ( /eel is readily magnetis$ by /rok+ x f end to end 9 "o direction ) ! pole ( a magnet1 & 9 ?is way compass ne$les & p[]ful b> magnets c be made4 ,! poles attract iron at a di/ance by induction1 j z a *>ge ( electricity1 be x positive or negative1 w attract a neutral pi? ball2 & ,dr4 ,gilb]t %[$ t a nor? pole always repels ano!r nor? pole & attracts a s\? pole1 :ile1 on ! o!r h&1 a s\? pole always repels a s\? pole & attracts a nor? pole4 ,?is c be prov$ by susp5d+ a magnetic ne$le l a pi?ball1 & approa*+ ano!r t[>ds x1 z illu/rat$ 9 figure #bf1 :]e ! nor? pole ,n attracts ! s\? ,s4 ,obvi\sly !re are two opposite k9ds ( magnetic poles1 z ( electricity1 :i* always appe> toge!r1 & l magnetic poles repel1 unlike magnetic poles attract ea* o!r4 ,x foll[s t ! magnetic pole ( ! compass ne$le :i* turns to ! nor? mu/ be unlike ! nor? & l ! s\? magnetic pole ( ! e>?4 ,in/ead ( call+ x ! nor?1 x w\ld be less confus+ to call x ! nor?-seek+ pole ( ! ne$le4 ,gilb]t made a t]ella1 or m9iature ( ! e>?1 z a magnet1 & n only demon/rat$ h[ ! compass ne$le sets along ! l9es jo9+ ! nor? & s\? magnetic poles1 b expla9$ ! v>iation & ! dip4 ,he imag9$ t ! magnetic poles co9cid$ ) ! geographical poles1 b1 z a matt] ( fact1 !y d n1 &1 moreov]1 !y are sl[ly mov+ r\nd ! geographical poles1 h5ce ! decl9ation ( ! ne$le1 t is to say its angle ( div]g5ce f ! true m]idian or nor? & s\? l9e1 is gradually *ang+4 ,! nor? magnetic pole ( ! e>? 0 actually discov]$ by ,sir ,john ,ross nor? ( ,briti% ,am]ica1 on ! coa/ ( ,boo?ia 7latitude #gj degrees #e' ,n1 longitude #if degrees #df' ,w71 :]e1 z =ese51 ! ne$le entirely lo/ its directive prop]ty & /ood upright1 or1 s to speak1 on its head4 ,! s\? magnetic pole lies 9 ! ,pr9ce ,alb]t range ( ,victona ,l&1 & 0 almo/ rea*$ by ,sir ,james ,cl>k ,ross4 ,! magnetism ( ! e>? is su* z might be produc$ by a p[]ful magnet inside1 b its orig9 is unkn[n1 al?\gh !re is reason to believe t masses ( lode/one or magnetic iron exi/ 9 ! cru/4 ,c\lomb f\nd t n only iron1 b all sub/ances are m or less magnetic1 & ,f>aday %[$ 9 #ahde t :ile "s are attract$ by a magnet o!rs are repell$4 ,! =m] he call$ p>amagnetic & ! latt] diamagnetic bodies4 ,! foll[+ is a li/ ( ^!4-- ,p>amagnetic ,diamagnetic ,iron ,bismu? ,nickel ,phosphorus ,cobalt ,antimony ,alum9ium ,z9c ,manganese ,m]cury ,*romium ,lead ,c]ium ,silv] ,titanium ,copp] ,plat9um ,wat] ,_m ores & ,alcohol salts ( ! ,tellurium above metals ,sel5ium ,oxyg5 ,sulphur ,?allium ,hydrog5 ,air ,we h !ories ( magnetism t r$uce x to a ph5om5on ( electricity1 ?\gh we are ignorant ( ! real nature ( bo?4 ,if we take a ?9 b> magnet & break x 9 two1 we f9d t we h n[ two %ort] magnets1 ea* ) its nor? & s\? poles1 t is to say1 poles ( ! same k9d z ! s\? & nor?--magnetic poles ( ! e>?4 ,if we break ea* ( ^! aga91 we get f\r small] magnets1 & we c repeat ! process z (t5 z we l4 ,x is suppos$1 !re=e1 t e atom ( ! b> is a little magnet 9 itself hav+ its two opposite poles1 & t 9 magnetis+ ! b> we h m]ely p>tially turn$ all ^! atoms 9 "o direction1 t is to say1 ) _! nor? poles po9t+ "o way & _! s\? poles ! o!r way1 z %[n 9 figure #bg4 ,! pol>ity ( ! b> only %[s itself at ! ends1 :]e ! molecul> poles are1 s to speak1 free4 ,!re are _m exp]im5ts :i* support ?is view4 ,= example1 if we heat a magnet r$ hot x loses its magnetism1 p]haps because ! heat has dis>rang$ ! p>ticles & set ! molecul> poles 9 all directions4 ,aga91 if we magnetise a piece ( s(t iron we c de/roy its magnetism by /rik+ x s z to agitate its atoms & ?r[ !m out ( l9e4 ,9 /eel1 :i* is iron ) a small admixture ( c>bon1 ! atoms are n s free z 9 s(t iron1 & h5ce1 :ile iron easily loses its magnetism1 /eel reta9s x1 ev5 "u a %ock1 b n "u a *]ry r$- heat4 ,nev]!less1 if we put ! atoms ( s(t iron "u a /ra9 by b5d+ x1 we %all f9d x reta9 its magnetism m l a bit ( /eel4 ,x has be5 f\nd1 too1 t ! atoms %[ an indisposition to be mov$ by ! magnetis+ =ce :i* is kn[n z ,,hy/]esis4 ,!y h a c]ta9 in]tia1 :i* c be ov]come by a slight %ock1 z ?\gh !y _h a difficulty ( turn+ 9 ! ranks to take up _! new positions4 ,ev5 if ?is molecul> !ory is true1 h[ev]1 x does n help u to expla9 :y a molecule ( matt] is a t9y magnet4 ,we h only pu%$ ! my/]y back to ! atom4 ,some?+ m is want$1 & electricians look = x 9 ! con/itution ( ! atom1 & 9 ! lum9if]\s e!r :i* is believ$ to surr\nd ! atoms ( matt]1 & to propagate n m]ely ! waves ( light1 b induction f "o electrifi$ body to ano!r4 ,we "k 9 pro( ( ?is e!real action t ! space ar\nd a magnet is magnetic4 ,?us1 if we lay a horse-%oe magnet on a table & spr9kle iron fil+s r\nd x1 !y w arrange !mselves 9 curv+ l9es betwe5 ! poles1 z %[n 9 figure #bh4 ,ea* fil+ has become a little magnet1 & ^! set !mselves end to end z ! molecules 9 ! metal are suppos$ to d4 ,! field ab\t ! magnet is replete ) ^! l9es1 :i* foll[ c]ta9 curves dep5d+ on ! arrangem5t ( ! poles4 ,9 ! horse- %oe magnet1 z se51 !y *iefly issue f "o pole & sweep r\nd to ! o!r4 ,!y are nev] brok51 & app>5tly !y are l9es ( /ress 9 ! circumambi5t e!r4 ,a pivot$ magnet t5ds to range itself along ^! l9es1 & ?us ! compass guides ! sailor on ! ocean by keep+ itself 9 ! l9e betwe5 ! nor? & s\? magnetic poles ( ! e>?4 ,f>aday call$ !m l9es ( magnetic =ce1 & said t ! /rong] ! magnet ! m ( ^! l9es pass ?r\gh a giv5 space4 ,along !m magnetic induction is suppos$ to be propagat$1 & a magnet is ?us enabl$ to attract iron or any o!r magnetic sub/ance4 ,! pole induces an opposite pole to itself 9 ! ne>e/ "p ( ! induc$ body & a l pole 9 ! remote "p4 ,consequ5tly1 z unlike poles attract & l repel1 ! s(t iron is attract$ by ! induc+ pole mu* z a pi?ball is attract$ by an electric *>ge4 ,! resemblances ( electricity & magnetism did n escape att5tion1 & ! d]angem5t ( ! compass ne$le by ! lightn+ fla%1 =m]ly s disa/r\s at sea1 po9t$ to an intimate connection betwe5 !m1 :i* 0 ultimately disclos$ by ,pr(essor ,o]/$1 ( ,cop5hag51 9 ! ye> #ahbj4 ,o]/$ 0 on ! outlook = ! requir$ clue1 & a happy *ance is said to h rew>d$ him4 ,8 exp]im5t is %[n 9 figure #bi1 :]e a wire convey+ a curr5t ( electricity fl[+ 9 ! direction ( ! arr[ is held ov] a pivot$ magnetic ne$le s t ! curr5t fl[s f s\? to nor?4 ,! ne$le w t5d to set itself at "r angles to ! wire1 its nor? or nor?-seek+ pole mov+ t[>ds ! we/4 ,if ! direction ( ! curr5t is rev]s$1 ! ne$le is deflect$ 9 ! opposite direction1 its nor? pole mov+ t[>ds ! ea/4 ,fur!r1 if ! wire is held bel[ ! ne$le1 9 ! fir/ place1 ! nor? pole w turn t[>ds ! ea/1 & if ! curr5t be rev]s$ x w move t[>ds ! we/4 ,! direction ( a curr5t c ?us be told ) ! aid ( a compass ne$le4 ,:5 ! wire is w\nd _m times r\nd ! ne$le on a bobb91 ! :ole =ms :at is call$ a galvanoscope1 z %[n 9 figure #cj1 :]e ,n is ! ne$le & ,b ! bobb94 ,:5 a prop] scale is add$ to ! ne$le by :i* its deflections c be accurately read1 ! in/rum5t becomes a curr5t measur] or galvanomet]1 = )9 c]ta9 limits ! deflection ( ! ne$le is proportional to ! /r5g? ( ! curr5t 9 ! wire4 ,a rule commonly giv5 = rememb]+ ! movem5t ( ! ne$le is z foll[s3--,imag9e y\rself laid along ! wire s t ! curr5t fl[s f y\r feet to y\r head2 !n if y face ! ne$le y w see its nor? pole g to ! left & its s\? pole to ! "r4 ,i f9d x simpl] to recollect t if ! curr5t fl[s f y\r head to y\r feet a nor? pole w move r\nd y f left to "r 9 front4 ,or1 aga91 if a curr5t fl[s f nor? to s\?1 a nor? pole w move r\nd x l ! sun r\nd ! e>?4 ,! influ5ce ( ! curr5t on ! ne$le implies a magnetic action1 & if we du/ iron fil+s ar\nd ! wire we %all f9d !y cl+ to x 9 conc5tric lay]s1 %[+ t circul> l9es ( magnetic =ce enclose x l ! wat] waves caus$ by a /one dropp$ into a pond4 ,figure #ca repres5ts ! section ( a wire c>ry+ a curr5t1 ) ! iron fil+s arrang$ 9 circles r\nd x4 ,s9ce a magnetic pole t5ds to move 9 ! direction ( ! l9es ( =ce1 we n[ see :y a nor? or s\? pole t5ds to move ,,r\nd a curr5t1 & :y a compass ne$le tries to set itself at "r angles to a curr5t1 z 9 ! orig9al exp]im5t ( ,o]/$4 ,! ne$le1 hav+ two opposite poles1 is pull$ 9 opposite directions by ! l9es1 & be+ pivot$1 sets itself tang5tically to !m4 ,7 x free & flexible1 x w\ld curve itself along "o ( ! l9es4 ,did x consi/ ( a s+le pole1 x w\ld revolve r\nd ! wire4 ,action & re-action are equal & opposite1 h5ce if ! ne$le is fix$ & ! wire free ! curr5t w move r\nd ! magnet2 & if bo? are free !y w circle r\nd ea* o!r4 ,apply+ ! above rule we %all f9d t :5 ! nor? pole moves f left to "r ! curr5t moves f "r to left4 ,amp]e ( ,p>is1 foll[+ ,o]/$1 promptly %[$ t two p>allel wires c>ry+ curr5ts attract$ ea* o!r :5 ! curr5ts fl[$ 9 ! same direction1 & repell$ ea* o!r :5 !y fl[$ 9 opposite directions4 ,?us1 9 figure #cb1 if ,a & ,b are ! two p>allel wires1 & ,a is m\nt$ on pivots & free to move 9 liquid contacts ( m]cury1 x w be attract$ or repell$ by ,b accord+ z ! two curr5ts fl[ 9 ! same or 9 opposite directions4 ,if ! wires cross ea* o!r at "r angles !re is no attraction or repulsion4 ,if !y cross at an acute angle1 !y w t5d to become p>allel l two compass ne$les1 :5 ! curr5ts are 9 "o direction1 & to op5 to a "r angle & close up ! o!r way :5 ! curr5ts are 9 opposite directions1 always t5d+ to arrange !mselves p>allel & fl[+ 9 ! same direction4 ,^! effects arise f ! circul> l9es ( =ce ar\nd ! wire4 ,:5 ! curr5ts are simil> ! l9es act z unlike magnetic poles & attract1 b :5 ! curr5ts are dissimil> ! l9es act z l magnetic poles & repel ea* o!r4 ,ano!r important discov]y ( ,amp]e is t a circul> curr5t behaves l a magnet2 & x has be5 sugge/$ by him t ! atoms are magnets because ea* has a circul> curr5t fl[+ r\nd x4 ,a s]ies ( circul> curr5ts1 su* z ! spiral ,s 9 figure #cc gives1 :5 connect$ to a batt]y ,c ,z1 is 9 fact a skeleton ,,electro-,,magnet hav+ its nor? & s\? poles at ! extremities4 ,if a rod or core ( s(t iron ,i be susp5d$ by fibres f a support1 x w be suck$ t[>ds ! middle ( ! coil z into a vortex1 by ! circul> magnetic l9es ( e spire or turn ( ! coil4 ,su* a comb9ation is sometimes call$ a sol5oid1 & is useful 9 practice4 ,:5 ! core ga9s ! int]ior ( ! coil x becomes a v]itable electromagnet1 z f\nd by ,arago1 hav+ a nor? pole at "o end & a s\? pole at ! o!r4 ,figure #cd illu/rates a common pok] magnetis$ 9 ! same way1 & support+ nails at bo? ends4 ,! pok] has become ! core ( ! electromagnet4 ,on rev]s+ ! direction ( ! curr5t ?r\gh ! spiral we rev]se ! poles ( ! core1 = ! pok] be+ ( s(t or wr\ght iron1 does n reta9 its magnetism l /eel4 ,if we /op ! curr5t altoge!r x ceases to be a magnet1 & ! nails w drop away f x4 ,amp]e's exp]im5t 9 figure #cb has %[n u t two curr5ts1 m or less p>allel1 influ5ce ea* o!r2 b 9 #ahca ,pr(essor ,f>aday ( ! ,royal ,in/itution1 ,london1 also f\nd t :5 a curr5t is />t$ & /opp$ 9 a wire1 x induces a mom5t>y & opposite curr5t 9 a p>allel wire4 ,?us1 if a curr5t is ,,/>t$ 9 ! wire ,b 7fig4 #cb7 9 direction ( ! arr[1 x w induce or give rise to a mom5t>y curr5t 9 ! wire ,a1 fl[+ 9 a contr>y direction to itself4 ,aga91 if ! curr5t 9 ,b be ,,/ope$1 a mom5t>y curr5t is set up 9 ! wire ,a 9 a direction ! same z t ( ! excit+ curr5t 9 ,b4 ,:ile ! curr5t 9 ,b is quietly fl[+ !re is no induc$ curr5t 9 ,a2 & x is only at ! />t or ! /oppage ( ! induc+ or ,,prim>y curr5t t ! induc$ or ,,second>y curr5t is set up4 ,"h aga9 we h ! influ5ce ( ! magnetic field ar\nd ! wire convey+ a curr5t4 ,?is is ! pr9ciple ( ! induction coil s mu* employ$ 9 m$ical electricity1 & ( ! trans=m] or conv]t] us$ 9 electric illum9ation4 ,x consi/s ess5tially1 z %[n 9 figure #ce1 ( two coils ( wire1 "o enclos+ ! o!r1 & bo? p>allel or conc5tric4 ,! inn] or prim>y coil ,p ,c is ( %ort ?ick wire ( l[ resi/ance1 & is trav]s$ by ! induc+ curr5t ( a batt]y ,b4 ,to increase its inductive effect a core ( s(t iron ,i ,c occupies its middle4 ,! out] or second>y coil ,s ,c is ( long ?9 wire t]m9at+ 9 two dis*>g+ po9ts ,d#a ,d#b4 ,an int]rupt] or hamm] key int]rupts or makes & breaks ! circuit ( ! prim>y coil v rapidly1 s z to excite a great _m induc$ curr5ts 9 ! second>y coil p] second1 & produce en]getic sp>ks betwe5 ! t]m9als ,d#a ,d#b4 ,! int]rupt] is actuat$ automatically by ! magnetism ( ! iron core ,i ,c1 = ! hamm] ,h has a s(t iron head :i* is attract$ by ! core :5 ! latt] is magnetis$1 & be+ ?us drawn away f ! contact screw ,c ,s ! circuit ( ! prim>y is brok51 & ! curr5t is /opp$4 ,! iron core !n ceases to be a magnet1 ! hamm] ,h spr+s back to ! contact screw1 & ! curr5t aga9 fl[s 9 ! prim>y circuit only to be int]rupt$ aga9 z be=e4 ,9 ?is way ! curr5t 9 ! prim>y coil is rapidly />t$ & /opp$ _m times a second1 & ?is1 z we "k1 induces correspond+ curr5ts 9 ! second>y :i* appe> z sp>ks at ! dis*>g+ po9ts4 ,! effect ( ! app>atus is enhanc$ by int]polat+ a cond5s] ,c ,c 9 ! prim>y circuit4 ,a cond5s] is a =m ( ,leyd5 j>1 suitable = curr5t electricity1 & consi/s ( lay]s ( t9foil sep>at$ f ea* o!r by %eets ( p>aff9 pap]1 mica1 or "s o!r conv5i5t insulator1 & alt]nate foils are connect$ toge!r4 ,! wires jo9+ ea* set ( plates are ! poles ( ! cond5s]1 & :5 ^! are connect$ 9 ! circuit ( a curr5t ! cond5s] is *>g$4 ,x c be dis*>g$ by jo9+ its two poles ) a wire1 & lett+ ! two opposite electricities on its plates ru% toge!r4 ,n[1 ! sudd5 dis*>ge ( ! cond5s] ,c ,c ?r\gh ! prim>y coil ,p ,c enhances ! inductive effect ( ! curr5t4 ,! batt]y ,b1 "h %[n by ! conv5tional symbol ,electrical ,symbol :]e ! ?ick da% is ! negative & ! ?9 da% ! positive pole1 is connect$ betwe5 ! t]m9als ,t#a ,t#b1 & a ,,commutator or pole- *ang] ,r1 turn$ ) a h&le1 p]mits ! direction ( ! curr5t to be rev]s$ at w4 ,figure #cf repres5ts ! ext]ior ( an ord9>y induction coil ( ! ,ruhmkorff patt]n1 ) its two coils1 "o ov] ! o!r ,c1 its commutator ,r1 & its sp>kl+ po9ts ,d#a;,d#b1 ! :ole be+ m\nt$ on a mahogany base1 :i* holds ! cond5s]4 ,! int]mitt5t1 or r alt]nat+1 curr5ts f ! second>y coil are (t5 appli$ to ! body 9 c]ta9 n]v\s disord]s4 ,:5 s5t ?r\gh glass tubes fill$ ) r>efi$ gases1 sometimes call$ ,geissl] tubes1 !y elicit gl[s ( _m col\rs1 vie+ 9 beauty ) ! fleet+ t9ts ( ! aurora pol>is1 :i*1 inde$1 is probably a simil> effect ( electrical dis*>ges 9 ! atmosph]e4 ,! action ( ! induction is rev]sible4 ,we c n only s5d a curr5t ( l[ pressure f a g5]ator ( weak electromotive =ce ?r\gh ! prim>y coil1 & ?us excite a curr5t ( high pressure 9 ! second>y coil1 b we c s5d a curr5t ( high pressure ?r\gh ! second>y coil & provoke a curr5t ( l[ pressure 9 ! prim>y coil ,! trans=m] or conv]t]1 a modifi$ induction coil us$ 9 di/ribut+ electricity to electric lamps & motors1 c n only trans=m a l[ pressure curr5t into a high1 b a high pressure curr5t into a l[4 ,z ! high pressure curr5ts are be/ able to ov]come ! resi/ance ( ! wire conv5+ !m1 x is cu/om>y to transmit high pressure curr5ts f ! g5]ator to ! di/ant place :]e !y are want$ by means ( small wires1 & !re trans=m !m into curr5ts ( ! pressure requir$ to light ! lamps or drive ! motors4 ,we come n[ to ano!r consequ5ce ( ,o]/$'s great discov]y1 :i* is d\btless ! mo/ important ( all1 namely1 ! g5]ation ( electricity f magnetism1 or1 z x is usually call$1 magneto-electric induction4 ,9 ! ye> #ahca ! illu/ri\s ,mi*ael ,f>aday fur!r succe$$ 9 demon/rat+ t :5 a magnet ,m is ?ru/ into a holl[ coil ( wire ,c1 z %[n 9 figure #cg1 a curr5t ( electricity is set up 9 ! coil :il/ ! motion la/s4 ,:5 ! magnet is )drawn aga9 ano!r curr5t is induc$ 9 ! rev]se direction to ! fir/4 ,if ! coil be clos$ ?r\gh a small galvanomet] ,g ! movem5ts ( ! ne$le to "o side or ! o!r w indicate ^! tempor>y curr5ts4 ,x foll[s f ! pr9ciple ( action & reaction t if ! magnet is kept /ill & ! coil ?ru/ ov] x simil> curr5ts w be induc$ 9 ! coil4 ,all t is necess>y is = ! wires to cut ! l9es ( magnetic =ce ar\nd ! magnet1 or1 9 o!r words1 ! l9es ( =ce 9 a magnetic field ,we h se5 already t a wire convey+ a curr5t c move a magnetic pole1 & we are !re=e prep>$ to f9d t a magnetic pole mov$ ne> a wire c excite a curr5t 9 x4 ,figure #ch illu/rates ! conditions ( ?is rem>kable effect1 :]e ,n & ,s are two magnetic poles ) l9es ( =ce betwe5 !m1 & ,w is a wire cross+ ^! l9es at "r angles1 :i* is ! be/ position4 ,if1 n[1 ?is wire be mov$ s z to s9k bodily ?r\gh ! pap] away f ! read]1 an electric curr5t fl[+ 9 ! direction ( ! arr[ w be induc$ 9 x4 ,if1 on ! contr>y1 ! wire be mov$ across ! l9es ( =ce t[>ds ! read]1 ! induc$ curr5t w fl[ oppositely to ! arr[4 ,moreov]1 if ! poles ( ! magnet ,n & ,s ex*ange places1 ! directions ( ! induc$ curr5ts w also be rev]s$4 ,?is is ! fundam5tal pr9ciple ( ! well kn[n dynamo-electric ma*9e1 popul>ly call$ a dynamo4 ,aga91 if we s5d a curr5t f "s ext]nal s\rce ?r\gh ! wire 9 ! direction ( ! arr[1 ! wire w move ,,( ,,itself across ! l9es ( =ce away f ! read]1 t is to say1 9 ! direction x w\ld ne$ to be mov$ 9 ord] to excite su* a curr5t2 & if1 on ! o!r h&1 ! curr5t be s5t ?r\gh x 9 ! rev]se direction to ! arr[1 x w move t[>ds ! read]4 ,?is is ! pr9ciple ( ! equally well-kn[n electric motor4 ,figure #ci %[s a simple me?od ( rememb]+ ^! directions4 ,let ! "r h& re/ on ! nor? pole ( a magnet & ! =ef+] be ext5d$ 9 ! direction ( ! l9es ( =ce1 !n ! out/ret*$ ?umb w indicate ! direction 9 :i* ! wire or conductor moves & ! b5t middle f+] ! direction ( ! curr5t4 ,^! ?ree digits1 z w be notic$1 are all at "r angles to ea* o!r1 & ?is relation is ! be/ = induc+ ! /ronge/ curr5t 9 a dynamo or ! mo/ en]getic movem5t ( ! conductor 9 an electric motor4 ,( c\rse 9 a dynamo-electric g5]ator ! /rong] ! magnetic field1 ! less ! resi/ance ( ! conductor1 & ! fa/] x is mov$ across ! l9es ( =ce1 t is to say1 ! m l9es x cuts 9 a second ! /rong] is ! curr5t produc$4 ,simil>ly 9 an electric motor1 ! /rong] ! curr5t & magnetic field ! fa/] w ! conductor move4 ,! mo/ conv5i5t motion to give ! conductor 9 practice is "o ( rotation1 & h5ce ! dynamo usually consi/s ( a coil or s]ies ( coils ( insulat$ wire t]m$ ! armature1 :i* is m\nt$ on a sp9dle & rapidly rotat$ 9 a /rong magnetic field betwe5 ! poles ( p[]ful magnets4 ,curr5ts are g5]at$ 9 ! coils1 n[ 9 "o direction !n 9 ano!r1 z !y revolve or cross diff]5t p>ts ( ! field2 &1 by means ( a device t]m$ a commutator1 ^! curr5ts c be collect$ or sift$ at w1 & l$ away by wires to an electric lamp1 an accumulator1 or an electric motor1 z desir$4 ,! "* ( ! electricity is precisely ! same z t g5]at$ 9 ! voltaic batt]y4 ,! commutator may only collect ! curr5ts z !y are g5]at$1 & supply :at is call$ an alt]nat+ curr5t1 t is to say1 a curr5t :i* alt]nates or *anges its direction sev]al hundr$ times a second1 or x may sift ! curr5ts z !y are produc$ & supply :at is t]m$ a cont9u\s curr5t1 t is1 a curr5t always 9 ! same direction1 l t ( a voltaic batt]y4 ,"s ma*9es are made to supply alt]nat+ curr5ts1 o!rs cont9u\s curr5ts4 ,ei!r class ( curr5t w d = electric lamps1 b only cont9u\s curr5ts are us$ = electo-plat+1 or1 9 g5]al1 = electric motors4 ,9 ! magneto-electric ma*9e ! ,,field ,,magnets are simply /eel b>s p]man5tly magnetis$1 b 9 ! ord9>y dynamo ! field magnets are electro-magnets excit$ to a high pit* by means ( ! curr5t g5]at$ 9 ! mov+ conductor or armature4 ,9 ! s]ies-w\nd ma*9e ! :ole ( ! curr5t g5]at$ 9 ! armature also goes ?r\gh ! coils ( ! field magnets4 ,su* a ma*9e is sket*$ 9 figure #dj1 :]e ,a is ! armature1 consi/+ ( an iron core surr\nd$ by coils ( wire & rotat+ 9 ! field ( a p[]ful electro-magnet ,,ns 9 ! direction ( ! arr[s4 ,= ! sake ( simplicity only twelve coils are repres5t$4 ,!y are all 9 circuit "o ) ano!r1 & a wire connects ! ends ( ea* coil to correspond+ metal b>s on ! commutator ,c4 ,^! b>s are insulat$ f ea* o!r on ! sp9dle ,x ( ! armature4 ,n[1 z ea* coil passes ?r\gh ! magnetic field 9 turn1 a curr5t is excit$ 9 x4 ,ea* coil !re=e resembles an individual cell ( a voltaic batt]y1 connect$ 9 s]ies4 ,! curr5t is drawn (f f ! r+ by two copp] bru%es b1 be :i* rub ^u ! b>s ( ! commutator at opposite ends ( a diamet]1 z %[n4 ,"o bru% is ! positive pole ( ! dynamo1 ! o!r is ! negative1 & ! curr5t w fl[ ?r\gh any wire or ext]nal circuit :i* may be connect$ ) ^!1 :e!r electric lamps1 motors1 accumulators1 electro-plat+ ba?s1 or o!r device4 ,! small arr[s %[ ! movem5ts ( ! curr5t ?r\gh\t ! ma*9e1 & ! t]m9als are m>k$ 77 positive & 7-7 negative4 ,x w be obs]v$ t ! curr5t excit$ 9 ! armature also fl[s ?r\gh ! coils ( ! electro-magnets1 & ?us keeps up _! /r5g?4 ,:5 ! ma*9e is fir/ />t$ ! curr5t is feeble1 because ! field ( ! magnets 9 :i* ! armature revolves is m]ely t due to ! dregs or residual magnetism left 9 ! s(t iron cores ( ! magnet s9ce ! la/ "t ! ma*9e 0 us$4 ,b ?is feeble curr5t exalts ! /r5g? ( ! field-magnets1 produc+ a /rong] field1 :i* 9 turn excites a /ill /rong] curr5t 9 ! armature1 & ?is process ( give & take goes on until ! full /r5g? or saturation ( ! magnets is atta9$4 ,su* is ! s]ies dynamo1 ( :i* ! well-kn[n ,gramme ma*9e is a type4 ,figure #da illu/rates ?is ma*9e z x is actually made1 ,a be+ ! armature revolv+ betwe5 ! poles ,,ns ( ! field-magnets ,m1 ,m1 ,m' ,m'1 on a sp9dle :i* is driv5 by means ( a belt on ! pulley ,p f a sep>ate eng9e ,! bru%es b b' ( ! commutator ,c collect ! curr5t1 :i* 9 ?is case is cont9u\s1 or con/ant 9 its direction4 ,! curr5t ( ! s]ies ma*9e v>ies ) ! resi/ance ( ! ext]nal or work+ circuit1 because t is includ$ 9 ! circuit ( ! field magnets & ! armature4 ,?us1 if we v>y ! numb] ( electric lamps f$ by ! ma*9e1 we %all v>y ! curr5t x is capable ( yield+4 ,) arc lamps 9 s]ies1 by add+ to ! numb] 9 circuit we increase ! resi/ance ( ! out] circuit1 & !re=e dim9i% ! /r5g? ( ! curr5t yield$ by ! ma*9e1 because ! curr5t1 weak5$ by ! increase ( resi/ance1 fails to excite ! field magnets z /rongly z be=e4 ,on ! o!r h&1 ) gl[ lamps arrang$ 9 p>allel1 ! rev]se is ! case1 & putt+ m lamps 9 circuit increases ! p[] ( ! ma*9e1 by dim9i%+ ! resi/ance ( ! out] circuit 9 provid+ m cross-cuts = ! curr5t4 ,?is1 ( c\rse1 is a drawback to ! s]ies ma*9e 9 places :]e ! numb] ( lamps to be light$ v>ies f "t to "t4 ,9 ! %unt-w\nd ma*9e ! field magnets are excit$ by div]t+ a small portion ( ! ma9 curr5t f ! armature ?r\gh !m1 by means ( a %unt or loop circuit4 ,?us 9 figure #db :]e ,c is ! commutator & b b' ! bru%es1 ,m is a %unt circuit ?r\gh ! magnets1 & ,e is ! ext]nal or work+ circuit ( ! ma*9e4 ,! small arr[s indicate ! directions ( ! curr5ts4 ,) ?is arrangem5t ! addition ( m gl[ lamps to ! ext]nal circuit ,e ,,dim9i%es ! curr5t1 because ! portion ( x :i* fl[s ?r\gh ! by-pa? ,m1 & excites ! magnets1 is less n[ t ! alt]native r\te = ! curr5t ?r\gh ,e is ( l[] resi/ance ?an be=e4 ,:5 few] gl[ lamps are 9 ! ext]nal circuit ,e1 & its resi/ance !re=e high]1 ! curr5t 9 ! %unt circuit ,m is great] ?an be=e1 ! magnets become /rong]1 & ! electromotive =ce ( ! armature is increas$4 ,! ,edison ma*9e is ( ?is type1 & is illu/rat$ 9 figure #dc1 :]e ,m ,m' are ! field magnets ) _! poles ,n ,s1 betwe5 :i* ! armature ,a is revolv$ by means ( ! belt ,b1 & a pulley se5 beh9d4 ,! lead+ wires ,w ,w convey ! curr5t f ! bru%es ( ! commutator to ! ext]nal circuit4 ,9 ?is ma*9e ! conductors ( ! armature are n coils ( wire1 b sep>ate b>s ( copp]4 ,9 %unt ma*9es ! v>iation ( curr5t due to a v>y+ numb] ( lamps 9 use occasions a rise & fall 9 ! brightness ( ! lamps :i* is undesirable1 & h5ce a ?ird class ( dynamo has be5 devis$1 :i* comb9es ! pr9ciples ( bo? ! s]ies & %unt ma*9es4 ,?is is ! comp\nd-w\nd ma*9e1 9 :i* ! magnets are w\nd p>tly 9 %unt & p>tly 9 s]ies ) ! armature1 9 su* a mann] t ! /r5g? ( ! field-magnets & ! electromotive =ce ( ! curr5t d n v>y mu*1 :atev] be ! numb] ( lamps 9 circuit4 ,9 alt]nate curr5t ma*9es ! electromotive =ce keeps con/ant1 z ! field- magnets are excit$ by a sep>ate ma*9e1 giv+ a cont9u\s curr5t4 ,we h already se5 t ! action ( ! dynamo is rev]sible1 & t j z a wire mov$ across a magnetic field supplies an electric curr5t1 s a wire at re/1 b conduct+ a curr5t across a magnetic field1 w move4 ,! electric motor is !re=e ess5tially a dynamo1 :i* on be+ trav]s$ by an electric curr5t f an ext]nal s\rce puts itself 9 motion4 ,?us1 if a curr5t be s5t ?r\gh ! armature ( ! ,gramme ma*9e1 %[n 9 figure #da1 ! armature w revolve1 & ! sp9dle1 by means ( a belt on ! pulley ,p1 c communicate its en]gy to ano!r ma*9e4 ,h5ce ! electric motor c be employ$ to "w la!s1 hoi/s1 lifts1 drive ! screws ( boats or ! :eels ( c>riages1 & = _m o!r purposes4 ,!re are num]\s types ( electric motor z ( ! dynamo 9 use1 b !y are all modifications ( ! simple cont9u\s or alt]nat+ curr5t dynamo4 ,obvi\sly1 s9ce me*anical p[] c be conv]t$ into electricity by ! dynamo1 & reconv]t$ into me*anical p[] by ! motor1 x is suffici5t to connect a dynamo & motor toge!r by insulat$ wire 9 ord] to transmit me*anical p[]1 :e!r x be d]iv$ f w9d1 wat]1 or fuel1 to any reasonable di/ance4 ,,*apt] ,v4 ,,electrolysis4 ,hav+ se5 h[ electricity c be g5]at$ & /or$ 9 consid]able quantity1 let u n[ turn to its practical uses4 ,( ^! by f> ! mo/ important are bas$ on its prop]ty ( develop+ light & heat z 9 ! electric sp>k1 *emical action z m ! voltamet]1 & magnetism z 9 ! electromagnet4 ,! words curr5t1 pressure1 & s on po9t to a c]ta9 analogy betwe5 electricity & wat]1 :i* helps ! imag9ation to figure :at c nei!r be se5 nor h&l$1 ?\gh x mu/ n be trac$ too f>4 ',wat]1 = example1 runs by ! =ce ( gravity f a place ( high] to a place ( l[] level4 ,! pressure ( ! /ream is great] ! m ! diff]5ce ( level or head ( wat] ,! /r5g? ( ! curr5t or quantity ( wat] fl[+ p] second is great] ! high] ! pressure1 & ! less ! resi/ance ( its *annel4 ,! p[] ( ! wat] or its rate ( do+ me*anical "w is great] ! high] ! pressure & ! /rong] ! curr5t4 ,s1 too1 electricity fl[s by ! electromotive =ce f a place ( high] to a place ( l[] electric level or pot5tial4 ,! electric pressure is great] ! m ! diff]5ce ( pot5tial or electromotive =ce4 ,! /r5g? ( ! electric curr5t or quantity ( electricity fl[+ p] second is great] ! high] ! pressure or electromotive =ce & ! less ! resi/ance ( ! circuit ,! p[] ( ! electricity or its rate ( do+ "w is great] ! high] ! electromotive =ce & ! /rong] ! curr5t4 ,x foll[s t a small quantity ( wat] or electricity at a high pressure w give u ! same am\nt ( en]gy z a l>ge quantity at a l[ pressure1 & our *oice ( "o or ! o!r w dep5d on ! purpose we h 9 view4 ,z a rule1 h[ev]1 a l>ge curr5t at a comp>atively l[ or mod]ate pressure is f\nd ! m conv5i5t 9 practice4 ,! electricity ( friction belongs to ! =m] category1 & ! electricity ( *emi/ry1 heat1 & magnetism to ! latt]4 ,! sp>k ( a factional or influ5ce ma*9e c be comp>$ to a highl& cat>act ( l(ty height b small volume1 :i* is m picturesque ?an useful1 & ! curr5t f a voltaic batt]y1 a !rmopile1 or a dynamo to a l[l& riv] :i* c be damm$ to turn a mill4 ,x is ! diff]5ce betwe5 a skitti% geld+ & a tame c>?orse4 ,n ! sp>k f an induction coil or ,leyd5 j>1 b a /rong & /eady curr5t at a l[ pressure1 is adapt$ = electrolysis or electrodeposition1 & h5ce ! voltaic batt]y or a special =m ( dynamo is usually employ$ 9 ?is "w4 ,a fla% ( lightn+ is ! v symbol ( t]rific p[]1 & yet1 accord+ to ! illu/ri\s ,f>aday1 x conta9s a small] am\nt ( electricity ?an ! feeble curr5t requir$ to decompose a s+le drop ( ra94 ,9 our simile ( ! mill dam & ! batt]y or dynamo1 ! dam corresponds to ! positive pole & ! riv] or sea bel[ ! mill to ! negative pole4 ,! mill-race w /& = ! wire jo9+ ! poles1 t is to say1 ! ext]nal circuit1 & ! mill-:eel = ! "w to be done 9 ! circuit1 :e!r x be a *emical = decomposition1 a telegraph in/rum5t1 an electric lamp1 or any o!r appliance4 ,z ! curr5t 9 ! race dep5ds on ! head ( wat]1 or diff]5ce ( level betwe5 ! dam & ! sea z well z on ! resi/ance ( ! *annel1 s ! curr5t 9 ! circuit dep5ds on ! electromotive =ce1 or diff]5ce ( pot5tial betwe5 ! positive & negative poles1 z well z on ! resi/ance ( ! circuit4 ,! relation betwe5 ^! is express$ by ! well-kn[n law ( ,ohm1 :i* runs3 ,a curr5t ( electricity is directly proportional to ! electromotive =ce & inv]sely proportional to ! resi/ance ( ! circuit4 ,9 practice electricity is measur$ by v>i\s units or /&>ds nam$ aft] celebrat$ electricians4 ,?us ! unit ( quantity is ! c\lomb1 ! unit ( curr5t or quantity fl[+ p] second is ! amp]e1 ! unit ( electromotive =ce is ! volt1 & ! unit ( resi/ance is ! ohm4 ,! quantity ( wat] or any o!r electrolyte decompos$ by electricity is proportional to ! /r5g? ( ! curr5t4 ,"o amp]e decomposes 4#jjjjicbd gramme ( wat] p] second1 lib]at+ 4#jjjjajchd gramme ( hydrog5 & 4#jjjjhbhf gramme ( oxyg54 ,! quantity 9 grammes ( any o!r *emical elem5t or ion :i* is lib]at$ f an electrolyte or body capable ( electro*emical decomposition 9 a second by a curr5t ( "o amp]e is giv5 by :at is call$ ! electro*emical equival5t ( ! ion4 ,?is is f\nd by multiply+ its ord9>y *emical equival5t or comb9+ weight by 4#jjjjajchd1 :i* is ! electro*emical equival5t ( hydrog54 ,?us ! weight ( metal deposit$ f a solution ( any ( its salts by a curr5t ( s _m amp]es 9 s _m seconds is equal to ! numb] ( amp]es multipli$ by ! numb] ( seconds1 & by ! electro*emical equival5t ( ! metal4 ,! deposition ( a metal f a solution ( its salt is v easily %[n 9 ! case ( copp]4 ,9 fact1 we h already se5 t 9 ! ,daniell cell ! curr5t decomposes a solution ( sulphate ( copp] & deposits ! pure metal on ! copp] plate4 ,if we simply make a solution ( blue vitriol 9 a glass beak] & dip ! wires f a voltaic cell into x1 we %all f9d ! wire f ! negative pole become fre%ly coat$ ) p>ticles ( new copp]4 ,! sulphate has be5 brok5 up1 & ! lib]at$ metal1 be+ positive1 ga!rs on ! negative electrode4 ,moreov]1 if we exam9e ! positive electrode we %all f9d x slightly eat5 away1 because ! sulphuric acid set free f ! sulphate has comb9$ ) ! p>ticles ( t wire to make new sulphate4 ,?us ! copp] is deposit$ on "o electrode1 namely1 ! ca?ode1 by :i* ! curr5t leaves ! ba?1 & at ! exp5se ( ! o!r electrode1 t is to say1 ! anode1 by :i* ! curr5t ent]s ! ba?4 ,! fact t ! weight ( metal deposit$ 9 ?is way f its salts is proportional to ! curr5t1 has be5 utilis$ = measur+ ! /r5g? ( curr5ts ) a f9e degree ( accuracy4 ,if1 = example1 ! tubes ( ! voltamet] describ$ on page #ch 7 graduat$1 ! volume ( gas evolv$ w\ld be a measure ( ! curr5t4 ,usually1 h[ev]1 x is ! weight ( silv] or copp] deposit$ f _! salts 9 a c]ta9 "t :i* gives ! curr5t 9 amp]es4 ,electro-plat+ is ! pr9cipal application ( ?is *emical process4 ,9 #ahje ,brugnatelli took a silv] m$al & coat$ x ) gold by mak+ x ! ca?ode 9 a solution ( a salt ( gold1 & us+ a plate ( gold = ! anode4 ,! %ops ( our jewell]s are n[ bright ) teapots1 salt cell>s1 spoons1 & o!r articles ( ! table made ( inf]ior metals1 b beautifi$ & pres]v$ f ru/ 9 ?is way4 ,figure #dd illu/rates an electro-plat+ ba? 9 :i* a numb] ( spoons are be+ plat$4 ,a portion ( ! vat ,v is cut away to %[ ! int]ior1 :i* conta9s a solution ,s ( ! d\ble cyanide ( gold & potassium :5 gold is to be laid1 & ! d\ble cyanide ( silv] & potassium :5 silv] is to be deposit$4 ,! electrodes are hung f metal rods1 ! anode ,a be+ a plate ( gold or silv] ,g1 z ! case may be1 & ! ca?ode ,c ! spoons 9 "q4 ,:5 ! curr5t ( ! batt]y or dynamo passes ?r\gh ! ba? f ! anode to ! ca?ode1 gold or silv] is deposit$ on ! spoons1 & ! ba? recup]ates its /r5g? by consum+ ! gold or silv] plate4 ,enorm\s quantities ( copp] are n[ deposit$ 9 a simil> way1 sulphate ( copp] be+ ! solution & a copp] plate ! anode4 ,l>ge articles ( iron1 su* z ! p>ts ( ordnance1 are sometimes copp]-plat$ to pres]ve !m f ! action ( ! atmosph]e4 ,seamless copp] pipes = convey+ /eam1 & wires ( pure copp] = conduct+ electricity1 are also deposit$1 & x is n unlikely t ! kettle ( ! future w be made by electrolysis4 ,nickel-plat+ is ano!r ext5sive bran* ( ! indu/ry1 ! :ite nickel =m+ a cloak = metals m subject to corrosion4 ,nickel is f\nd to deposit be/ f a solution ( ! d\ble sulphate ( nickel & ammonia4 ,alum9ium1 h[ev]1 has n yet be5 successfully deposit$ by electricity4 ,9 #ahcf ,de la ,rue obs]v$ t copp] laid 9 ?is mann] on ano!r surface took on its "u side an accurate impression ( t surface1 ev5 to ! scrat*es on x1 & ?ree ye>s lat] ,jacobi1 ( ,/4 ,pet]sburg1 & ,jordan1 ( ,london1 appli$ ! me?od to mak+ copies or replicas ( m$als & woodcuts4 ,ev5 non-metallic surfaces c\ld be reproduc$ 9 copp] by tak+ a ca/ ( !m 9 wax & l9+ ! m\ld ) f9e plumbago1 :i*1 be+ a conductor1 s]v$ z a ca?ode to receive ! lay] ( metal4 ,x is by ! process ( electrotyp+ or galvano- pla/ics t ! copp] faces = pr9t+ woodcuts are prep>$1 & copies made ( seals or m$als4 ,natural objects1 su* z fl[]s1 f]ns1 leaves1 fea!rs1 insects1 & liz>ds1 c be prettily coat$ ) bronze or copp]1 n to speak ( gold & silv]1 by a simil> process4 ,!y are too delicate to be coat$ ) black lead 9 ord] to receive ! sk9 ( metal1 b !y c be dipp$ 9 solutions1 leav+ a film :i* c be r$uc$ to gold or silv]4 ,= in/ance1 !y may be soak$ 9 an alcoholic solution ( nitrate ( silv]1 made by %ak+ #b p>ts ( ! cry/als 9 #ajj p>ts ( alcohol 9 a /opp]$ bottle4 ,:5 dry1 ! object %\ld be susp5d$ "u a glass %ade & expos$ to a /ream ( sulphurett$ hydrog5 gas2 or x may be imm]s$ 9 a solution ( #a "p ( phosphorus 9 #ae p>ts ( bisulphide ( c>bon1 #a "p ( bees-wax1 #a "p ( spirits ( turp5t9e1 #a "p ( asphaltum1 & #a_/h "p ( ca\t*\c dissolv$ 9 bisulphide ( c>bon4 ,?is leaves a sup]ficial film :i* is metallis$ by dipp+ 9 a solution ( #bj gra9s ( nitrate ( silv] to a p9t ( wat]4 ,on ?is metallic film a ?ick] lay] ( gold & silv] 9 diff]5t %ades c be deposit$ by ! curr5t1 & ! silv] surface may also be oxidis$ by wa%+ x 9 a weak solution ( plat9um *loride4 ,electrolysis is also us$ to "s ext5t 9 r$uc+ metals f _! ores1 9 blea*+ fibre1 9 manufactur+ hydrog5 & oxyg5 f wat]1 & 9 ! *emical treatm5t ( sewage4 ,,*apt] ,,vi4 ,,! ,,telegraph ,,& ,,telephone4 ,l ! philosoph]'s /one1 ! elixir ( y\?1 & p]petual motion1 ! telegraph 0 long a dream ( ! imag9ation4 ,9 ! sixte5? c5tury1 if n be=e1 x 0 believ$ t two magnetic ne$les c\ld be made sympa!tic1 s t :5 "o 0 mov$ ! o!r w\ld likewise move1 h[ev] f> ap>t !y 71 & ?us enable two di/ant fri5ds to communicate _! m9ds to "o ano!r4 ,! idea 0 prophetic1 al?\gh ! means ( giv+ effect to x 7 mi/ak54 ,x became practicable1 h[ev]1 :5 ,o]/$ discov]$ t a magnetic ne$le c\ld be swung to "o side or ! o!r by an electric curr5t pass+ ne> x4 ,! illu/ri\s ,laplace 0 ! fir/ to sugge/ a telegraph on ?is pr9ciple4 ,a wire connect+ ! two poles ( a batt]y is trav]s$1 z we "k1 by an electric curr5t1 :i* makes ! r\nd ( ! circuit1 & only fl[s :5 t circuit is complete4 ,h[ev] long ! wire may be1 h[ev] f> x may run betwe5 ! poles1 ! curr5t w foll[ all its w9d+s1 & f9i% its c\rse f pole to pole ( ! batt]y4 ,y may lead ! wire across ! ocean & back1 or r\nd ! _w if y w1 & ! curr5t w travel ?r\gh x4 ,! mom5t y break ! wire or circuit1 h[ev]1 ! curr5t w /op4 ,by its electromotive =ce x c ov]come ! resi/ance ( ! _m miles ( conductor2 b unless x be unusually /rong x _c leap across ev5 a m9ute gap ( air1 :i* is "o ( ! be/ insulators4 ,if1 !n1 we h a simple device easily manipulat$ by :i* we c int]rupt ! circuit ( ! batt]y1 9 accordance ) a giv5 code1 we %all be able to s5d a s]ies ( curr5ts ?r\gh ! wire & make s5sible signals :]ev] we *oose4 ,^! signs c be produc$ by ! deviation ( a magnetic ne$le1 z ,laplace po9t$ out1 or by caus+ an electro-magnet to attract s(t iron1 or by *emical decomposition1 or any o!r s5sible effect ( ! curr5t4 ,amp]e develop$ ! idea ( ,laplace into a def9ite plan1 & 9 #ahcj or !reab\t ,rit*ie1 9 ,london1 & ,b>on ,s*ill+1 9 ,/4 ,pet]sburg1 exhibit$ exp]im5tal models4 ,9 #ahcc & aft]w>ds ,pr(essors ,gauss & ,web] in/all$ a private telegraph betwe5 ! obs]vatory & ! physical cab9et ( ! ,univ]sity ( ,gott+54 ,moreov]1 9 #ahcf ,william ,fo!rgill ,cooke1 a retir$ surgeon ( ! ,madras army1 att5d+ lectures on anatomy at ! ,univ]sity ( ,heidelb]g1 saw an exp]im5tal telegraph ( ,pr(essor ,moncke1 :i* turn$ all 8 ?\ghts to ! subject4 ,on return+ to ,london he made ! acqua9tance ( ,pr(essor ,:eat/one1 ( ,k+'s ,college1 :o 0 also exp]im5t+ 9 ?is direction1 & 9 #ahcf !y took out a pat5t = a ne$le telegraph4 ,x 0 tri$ successfully betwe5 ! ,eu/on t]m9us & ! ,camd5 ,t[n /ation ( ! ,london & ,nor?-,we/]n ,railway on ! ev5+ ( ,july #be?1 #ahcg1 9 pres5ce ( ,mr4 ,rob]t ,/eph5son1 & o!r em95t eng9e]s4 ,:eat/one1 sitt+ 9 a small room ne> ! book+-(fice at ,eu/on1 s5t ! fir/ message to ,cooke at ,camd5 ,t[n1 :o at once repli$4 ,nev]1 said ,:eat/one1 did ,i feel su* a tumultu\s s5sation be=e1 z :51 all alone 9 ! /ill room1 ,i he>d ! ne$les click1 & z ,i spell$ ! words ,i felt all ! magnitude ( ! inv5tion pron\nc$ to be practicable )\t cavil or dispute4 ,! importance ( ! telegraph 9 work+ railways 0 manife/1 & yet ! directors ( ! company 7 s purbl9d z to ord] ! removal ( ! app>atus1 & x 0 n until two ye>s lat] t ! ,great ,we/]n ,railway ,company adopt$ x on _! l9e f ,padd+ton to ,we/ ,drayton1 & subsequ5tly to ,sl\gh4 ,?is 0 ! fir/ telegraph = public use1 n m]ely 9 ,engl&1 b ! _w4 ,! *>ge = a message 0 only a %ill+1 nev]!less few p]sons avail$ !mselves ( ! new inv5tion1 & x 0 n until its fame 0 spread abroad by ! clev] capture ( a murd]] nam$ ,tawell t x began to prosp]4 ,tawell _h kill$ a woman at ,sl\gh1 & on leav+ 8 victim took ! tra9 = ,padd+ton4 ,! police1 appris$ ( ! murd]1 telegraph$ a description ( him to ,london4 ,! orig9al five ne$le in/rum5t1 n[ 9 ! museum ( ! ,po/ ,(fice1 _h a dial 9 ! %ape ( a diamond1 on :i* 7 m>k$ ! lett]s ( ! alphabet1 & ea* lett] ( a ^w 0 po9t$ out by ! movem5ts ( a pair ( ne$les4 ,! dial _h no lett] q1 & z ! man 0 describ$ z a quak] ! ^w 0 s5t kwak]4 ,:5 ! tram arriv$ at ,padd+ton he 0 %ad[$ by detectives1 & to 8 utt] a/oni%m5t 0 quietly arre/$ 9 a tav]n ne> ,cannon ,/reet4 ,9 ,cooke & ,:eat/one's e>ly telegraph ! wire travell$ ! :ole r\nd ( ! circuit1 b x 0 soon f\nd t a return wire 9 ! circuit 0 unnecess>y1 s9ce ! e>? itself c\ld take ! place ( x4 ,"o wire f ! s5d+ /ation to ! receiv+ /ation 0 suffici5t1 provid$ ! app>atus at ea* end 7 prop]ly connect$ to ! gr\nd4 ,?is use ( ! e>? n only sav$ ! exp5se ( a return wire1 b dim9i%$ ! resi/ance ( ! circuit1 because ! e>? (f]$ practically no resi/ance4 ,figure #de is a diagram ( ! connections 9 a simple telegraph circuit4 ,at ea* ( ! /ations !re is a batt]y ,b ,b'1 an int]ruptor or s5d+ key ,k ,k'to make & break ! cont9uity ( ! circuit1 a receiv+ in/rum5t ,r ,r'to indicate ! signal curr5ts by _! s5sible effects1 & connections ) gr\nd or e>? plates ,e ,e' to engage ! e>? z a return wire4 ,^! are usually copp] plates buri$ 9 ! moi/ subsoil or ! wat] pipes ( a city4 ,! l9e wire is commonly ( iron support$ on poles1 b insulat$ f !m by e>!nw>e cups or insulators4 ,at ! /ation on ! left ! key is 9 ! act ( ,,s5d+ a message1 & at ! po/ on ! "r x is con=mably 9 ! position = receiv+ ! message4 ,! key is s con/ruct$ t :5 x is at re/ x puts ! l9e 9 connection ) ! e>? ?r\gh ! ,,receiv+ ,,in/rum5t & ! e>? plate4 ,! key ,k consi/s ess5tially ( a spr+-lev]1 ) two plat9um contacts1 s plac$ t :5 ! lev] is press$ d[n by ! h& ( ! telegraphi/ x breaks contact ) ! receiv] ,r1 & puts ! l9e-wire ,l 9 connection ) ! e>? ,e ?r\gh ! batt]y ,b1 z %[n on ! left4 ,a curr5t !n fl[s into ! l9e & trav]ses ! receiv] ,r' at ! di/ant /ation1 return+ or seem+ to return to ! s5d+ batt]y by way ( ! e>? plate ,e' on ! "r & ! int]m$iate gr\nd4 ,! duration ( ! curr5t is at ! w ( ! op]ator :o works ! s5d+-key1 & x is pla9 t signals c be made by curr5ts ( v>i\s l5g?s4 ,9 ! ,morse code ( signals1 :i* is n[ univ]sal1 only two l5g?s ( curr5t are employ$-- namely1 a %ort1 mom5t>y pulse1 produc$ by in/ant contact ( ! key1 & a jet giv5 by a contact ab\t ?ree times long]4 ,^! two signals are call$ dot & da%1 & ! code is m]ely a suitable comb9ation ( !m to signify ! sev]al lett]s ( ! alphabet4 ,?us e1 ! commone/ lett] 9 ,engli%1 is telegraph$ by a s+le dot1 & ! lett] t by a s+le da%1 :ile ! lett] a is indicat$ by a dot foll[$ aft] a brief int]val or space by a da%4 ,obvi\sly1 if two k9ds ( curr5t are us$1 t is to say1 if ! poles ( ! batt]y are rev]s$ by ! s5d+-key1 & ! direction ( ! curr5t is consequ5tly rev]s$ 9 ! circuit1 !re is no ne$ to alt] ! l5g? ( ! signal curr5ts1 because a mom5t>y curr5t s5t 9 "o direction w /& = a dot & 9 ! o!r direction = a da%4 ,z a matt] ( fact1 ! code is us$ 9 bo? ways1 accord+ to ! nature ( ! l9e & receiv+ in/rum5t4 ,on subm>9e cables & ) ne$le & mirror in/rum5ts1 ! signals are made by rev]s+ curr5ts ( equal duration1 b on l& l9es work$ by ,morse in/rum5ts & s\nd]s1 !y are produc$ by %ort & long curr5ts4 ,! ,morse code is also us$ 9 ! army = signall+ by wav+ flags or fla%+ lights1 & may also be s]viceable 9 private life4 ,telegraph cl]ks h be5 kn[n to speak ) ea* o!r 9 company by w9k+ ! "r & left eye1 or tapp+ ) _! teaspoon on a cup & sauc]4 ,any two di/9ct signs1 h[ev] made1 c be employ$ z a telegraph by means ( ! ,morse code1 :i* runs z %[n 9 figure #df4 ,! receiv+ in/rum5ts ,r ,r' may consi/ ( a magnetic ne$le pivott$ on its c5tre & surr\nd$ by a coil ( wire1 ?r\gh :i* ! curr5t passes & deflects ! ne$le to "o side or ! o!r1 accord+ to ! direction 9 :i* x fl[s4 ,su* 0 ! pione] in/rum5t ( ,cooke & ,:eat/one1 :i* is /ill employ$ 9 ,engl& 9 a simplifi$ =m z ! s+le & d\ble ne$le-in/rum5t on "s ( ! local l9es & 9 railway telegraphs4 ,! signals are made by s5d+ mom5t>y curr5ts 9 opposite directions by a d\ble curr5t key1 :i* 7unlike ! key ,k 9 figure #de7 rev]ses ! poles ,a 4- ,j -4-4 ,b -444 ,k -4- ,c 444 ,l -- ,d -44 ,m - - ,e 4 ,n -4 ,f 4-4 ,o 4 4 ,g --4 ,q 44-4 ,h 4 44 ,r 4 44 ,i 44 ,s 444 #a 4--4 ,t - #b 44-44 ,u 44- #c 444-4 ,v 444- #d 4444- ,w 4- #e --- ,x 4-44 #f 444444 ,y 44 44 #g --44 ,z 444 4 #h -44 44 4 44 #i -44- ,p]iod 44--44 #j ---- ,comma 4-4- ,! ,int]national 7,morse7 code us$ else:]e is ! same z ! above1 ) ! foll[+ exceptions3 ,c -4-4 ,q --4- ,f 4 -4 ,r 4-4 ,j 4--- ,x -44- ,l 4-44 ,y -4-- ,o --- ,z --44 ,p 4--4 ,,fig4 #df4--,morse ,signal ,alphabet4 ( ! batt]y1 9 putt+ ! l9e to "o or ! o!r1 & ?us mak+ ! dot signal ) ! positive & ! da% signal ) ! negative pole4 ,x foll[s t if ! dot is indicat$ by a ?r[ ( ! ne$le to ! "r side1 a da% w be giv5 by a ?r[ to ! left4 ,mo/ ( ! telegraph in/rum5ts = l& l9es are bas$ on ! pr9ciple ( ! electro-magnet4 ,we h already se5 7page #ei7 h[ ,amp]e f\nd t a spiral ( wire ) a curr5t fl[+ 9 x behav$ l a magnet & 0 able to suck a piece ( s(t iron into x4 ,if ! iron is all[$ to rema9 !re z a core1 ! comb9ation ( coil & core becomes an electro-magnet1 t is to say1 a magnet :i* is only a magnet s long z ! curr5t passes4 ,figure #dg repres5ts a simple horse-%oe electro-magnet z inv5t$ by ,/urgeon4 ,a ,u-%ap$ core ( s(t iron is w\nd ) insulat$ wire ,w1 & :5 a curr5t is s5t ?r\gh ! wire1 ! core is f\nd to become magnetic ) a nor? pole 9 "o end & a s\? pole 9 ! o!r4 ,^! poles are !re=e able to attract a sep>ate piece ( s(t iron or armature ,a4 ,:5 ! curr5t is /opp$1 h[ev]1 ! core ceases to be a magnet & ! armature drops away4 ,9 practice ! electromagnet usually takes ! =m %[n 9 figure #dh1 :]e ! poles are two bobb9s or sol5oids ( wire #fa hav+ /raight cores ( iron :i* are unit$ by an iron b> ,b1 & ,a is ! armature4 ,su* an electromagnet is a m p[]ful device ?an a sw++ ne$le1 & bett] able to actuate a me*anism4 ,x became ! f\ndation ( ! record+ in/rum5t ( ,samuel ,morse1 ! fa!r ( ! telegraph 9 ,am]ica4 ,! ,morse1 or1 r1 ,morse & ,vail in/rum5t1 actually m>ks ! signals 9 dots & da%es on a ribbon ( mov+ pap]4 ,figure #di repres5ts ! ,morse in/rum5t1 9 :i* an electromagnet ,m attracts an iron armature ,a :5 a curr5t passes ?r\gh its bobb9s1 & by means ( a lev] ,l connect$ ) ! armature raises ! edge ( a small disc out ( an ink-pot ,i aga9/ ! surface ( a travell+ slip ( pap] ,p1 & m>ks a dot or da% ^u x z ! case may be4 ,! re/ ( ! app>atus consi/s ( details & accessories = its action & adju/m5t1 toge!r ) ! s5d+-key ,k1 :i* is us$ 9 ask+ = repetitions ( ! words1 if necess>y4 ,a p]man5t record ( ! message is ( c\rse conv5i5t1 nev]!less ! op]ators pref] to read ! signals by ! e>1 r ?an ! eye1 &1 to ! annoyance ( ,morse1 w\ld li/5 to ! click ( ! m>k+ disc r ?an deciph] ! m>ks on ! pap]4 ,consequ5tly ,alfr$ ,vail1 ! collaborator ( ,morse1 :o really inv5t$ ! ,morse code1 produc$ a modification ( ! record+ in/rum5t work+ solely = ! e>4 ,! s\nd]1 z x is call$1 has l>gely driv5 ! pr9t] f ! field4 ,?is neat little in/rum5t is %[n 9 figure #ej1 :]e ,m is ! electromagnet1 & ,a is ! armature :i* *att]s up & d[n betwe5 two metal /ops1 z ! curr5t is made & brok5 by ! s5d+-key1 & ! op]ator li/5+ to ! s\nds int]prets ! message lett] by lett] & ^w by ^w4 ,! motion ( ! armature 9 bo? ( ^! in/rum5ts takes a s5sible "t1 b ,alex&] ,ba91 ( ,?urso1 by trade a wat*mak]1 & by nature a g5ius1 inv5t$ a *emical telegraph :i* 0 capable ( a prodigi\s activity4 ,! in/rum5t ( ,ba9 resembl$ ! ,morse 9 m>k+ ! signals on a tape ( mov+ pap]1 b ?is 0 done by electrolysis or electro-*emical decomposition4 ,! pap] 0 soak$ 9 a solution ( iodide ( potassium 9 />* & wat]1 & ! signal curr5ts 7 pass$ ?r\gh x by a m>k+ /ylus or p5cil ( iron4 ,! electricity decompos$ ! solution 9 its passage & left a blue /a9 on ! pap]1 :i* correspond$ to ! dot & da% ( ! ,morse app>atus4 ,! ,ba9 telegraph c record ov] #ajjj words a m9ute z aga9/ #dj to #ej by ! ,morse or s\nd]1 nev]!less x has fall5 into disuse1 p]haps because ! solution 0 tr\blesome4 ,x is /at$ t a c]ta9 bl9d op]ator c\ld read ! signals by ! smell ( ! *emical action2 & we c well believe x4 ,9 fact1 ! telegraph appeals to e s5se1 = a deaf cl]k c feel ! movem5ts ( a s\nd]1 & ! signals ( ! curr5t c be told )\t any in/rum5t by ! m]e ta/e ( ! wires ins]t$ 9 ! m\?4 ,a skilful telegraphi/ c transmit tw5ty-five words a m9ute ) ! s+le-curr5t key1 & ne>ly twice z _m by ! d\ble-curr5t key1 & if we rememb] t an av]age ,engli% ^w requires fifte5 sep>ate signals1 ! numb] w seem rem>kable2 b by means ( ,:eat/one's automatic s5d] #aej words or m c be s5t 9 a m9ute4 ,among telegraphs design$ to pr9t ! message 9 ,roman type1 t ( ,pr(essor ,david ,edw>d ,hughes is d\btless ! fitte/1 s9ce x is n[ 9 g5]al use on ! ,cont95t1 & conveys our ,cont95tal news4 ,9 ?is app>atus ! electromagnet1 on attract+ its armature1 presses ! pap] aga9/ a revolv+ type :eel & receives ! pr9t ( a type1 s t ! message c be read by a novice4 ,to ?is effect ! type :eel at ! receiv+ /ation has to keep 9 p]fect "t z x revolves1 s t ! "r lett] %all be above ! pap] :5 ! curr5t passes4 ,small v>ieties ( ! type-pr9t] are employ$ = ! di/ribution ( news & prices 9 mo/ ( ! l>ge t[ns1 be+ locat$ 9 hotels1 re/aurants1 saloons1 & o!r public places1 & report+ prices ( /ocks & bonds1 horse races1 & sport+ & g5]al news4 ,! duplex sy/em1 :]eby two messages1 "o 9 ei!r direction1 c be s5t ov] "o wire simultane\sly )\t int]f]+1 & ! quadruplex sy/em1 :]eby f\r messages1 two 9 ei!r direction1 are also s5t at once1 h come into use :]e ! traffic ov] ! l9es is v great4 ,bo? ( ^! sy/ems & _! modifications dep5d on an +5i\s arrangem5t ( ! app>atus at ea* end ( ! l9e1 by :i* ! signal curr5ts s5t out f "o /ation d n influ5ce ! receiv]s !re1 b leave !m free to indicate ! curr5ts f ! di/ant /ation4 ,:5 ! ,:eat/one ,automatic ,s5d] is employ$ ) ^! sy/ems ab\t #ejj words p] m9ute c be s5t ?r\gh ! l9e4 ,press news is g5]ally s5t by night1 & x is on record1 t dur+ a great debate 9 ,p>liam5t1 z _m z half a million words p\r$ out ( ! ,c5tral ,telegraph ,/ation at ,/4 ,m>t9's-le-,gr& 9 a s+le night to all p>ts ( ! c\ntry4 ,errors occur n[ & !n ?r\gh bad p5man%ip or ! simil>ity ( c]ta9 signals1 & amus+ telegrams h be5 s5t out1 z :5 ! nom9ation ( ,mr4 ,br& = ! ,speak]%ip ( ! ,commons took ! =m ( ,propos$ to br& ,speak]2 & an excursion p>ty assur$ _! fri5ds at home ( _! security by ! message1 ,arriv$ all tight4 ,telegraphs1 9 ! lit]al s5se ( ! ^w1 :i* actually write ! message z ) a p51 & make a copy or facsimile ( ! orig9al1 h be5 inv5t$ f "t to "t4 ,su* are ! telegraphic p5 ( ,mr4 ,e4 ,a4 ,c[p]1 & ! telautographs ( ,mr4 ,j4 ,h4 ,rob]tson & ,mr4 ,eli%a ,gray4 ,! fir/ two are bas$ on a me?od ( v>y+ ! /r5g? ( ! curr5t 9 accordance ) ! curves ( ! h&writ+1 & mak+ ! v>i$ curr5t actuate by means ( magnetism a writ+ p5 or /ylus at ! di/ant /ation4 ,! in/rum5t ( ,gray1 :i* is ! mo/ successful1 works by int]mitt5t curr5ts or electrical impulses1 t excite electro-magnets & move ! /ylus at ! f> end ( ! l9e4 ,!y are too complicat$ = description "h1 & are n ( mu* practical importance4 ,telegraphs = transmitt+ sket*es & draw+s h also be5 devis$ by ,d',abl9c\rt & o!rs1 b !y h n come into g5]al use4 ,( late ano!r /ep =w>d has be5 tak5 by ,mr4 ,am/utz1 :o has inv5t$ an app>atus = transmitt+ photographic pictures to a di/ance by means ( electricity4 ,! sy/em may be describ$ z a comb9ation ( ! photograph & telegraph4 ,an ord9>y negative picture is tak51 & !n impress$ on a gelat9e plate s5sitis$ ) bi*romate ( pota%4 ,! p>ts ( ! gelat9e 9 light become insoluble1 :ile ! p>ts 9 %ade c be wa%$ away by wat]4 ,9 ?is way a relief or engrav+ ( ! picture is obta9$ on ! gelat9e1 & a cross section ?r\gh ! plate w\ld1 if look$ at edgeways1 appe> s]rat$1 or up & d[n1 l a section ( c\ntry or ! trace ( ! /ylus 9 ! record ( a phonograph4 ,! gelat9e plate ?us c>v$ by ! action ( light & wat] is wrapp$ r\nd a revolv+ drum or b>rel1 & a spr+ /ylus or po9t is caus$ to pass ov] x z ! b>rel revolves1 aft] ! mann] ( a phonographic cyl9d]4 ,9 do+ s ! /ylus rises & falls ov] ! projections 9 ! plate & works a lev] aga9/ a set ( telegraph keys1 :i* op5 electric contacts & break ! connections ( an electric batt]y :i* is jo9$ betwe5 ! keys & ! e>?4 ,!re are f\r keys1 & :5 !y are unt\*$ ! curr5t splits up ?r\gh f\r by-pa?s or bobb9s ( wire be=e x ent]s ! l9e wire & passes to ! di/ant /ation4 ,:5 any ( ! keys are t\*$1 h[ev]1 ! correspond+ by-pa? or bobb9 is cut out ( circuit4 ,! suppression ( a by-pa? or *annel = ! curr5t has ! effect ( add+ to ! resi/ance ( ! l9e1 & !re=e ( dim9i%+ ! /r5g? ( ! curr5t4 ,:5 all ! keys are unt\*$ ! resi/ance is lea/ & ! curr5t /ronge/4 ,on ! o!r h&1 :5 all ! keys b ! la/ are t\*$1 ! resi/ance is greate/ & ! curr5t weake/4 ,by ?is device x is easy to see t z ! /ylus or trac] s9ks into a holl[ ( ! gelat9e1 or rises ov] a height1 ! curr5t 9 ! l9e becomes /rong] or weak]4 ,at ! di/ant /ation ! curr5t passes ?r\gh a sol5oid or holl[ coil ( wire connect$ to ! e>? & magnetises x1 s z to pull ! s(t iron plug or core ) great] or less =ce into its holl[ int]ior4 ,! up & d[n movem5t ( ! plug actuates a grav+ /ylus or po9t ?r\gh a lev]1 & engraves a copy ( ! orig9al gelat9e trace on ! surface ( a wax or gelat9e plate ov]ly+ ano!r b>rel or drum1 :i* revolves at a rate correspond+ to t ( ! b>rel at ! transmitt+ /ation4 ,9 ?is way a facsimile ( ! gelat9e picture is produc$ at ! di/ant /ation1 & an electrotype or cli*e ( x c be made = pr9t+ purposes4 ,! me?od is1 9 fact1 a species ( electric l9e grav+1 & ,mr4 ,am/utz hopes to apply x to engrav+ on gold1 silv]1 or any s(t metal1 n necess>ily at a di/ance4 ,we "k t an electric curr5t 9 "o wire c induce a transi5t curr5t 9 a neighb\r+ wire1 & ! fact has be5 utilis$ 9 ! ,unit$ ,/ates by ,phelps & o!rs to s5d messages f mov+ tra9s4 ,! signal curr5ts are int]mitt5t1 & :5 !y are pass$ ?r\gh a conductor on ! tra9 !y excite correspond+ curr5ts 9 a wire run along ! track1 :i* c be int]pret$ by ! hum !y make 9 a telephone4 ,exp]im5ts rec5tly made by ,mr4 ,w4 ,h4 ,preece = ! ,po/ ,(fice %[ t ) curr5ts ( suffici5t /r5g? & prop] app>atus messages c be s5t ?r\gh ! air = five miles or m by ?is me?od ( induction4 ,we come n[ to ! subm>9e telegraph1 :i* diff]s 9 _m respects f ! ov]l& telegraph4 ,obvi\sly1 s9ce wat] & moi/ e>? is a conductor1 a wire to convey an electric curr5t mu/ be insulat$ if x is int5d$ to lie at ! bottom ( ! sea or buri$ und]gr\nd4 ,! be/ mat]ials = ! purpose yet discov]$ are gutta-p]*a & india-rubb]1 :i* are bo? flexible & v good insulators4 ,! fir/ subm>9e cable 0 laid across ! ,*annel f ,dov] to ,calais 9 #ahea1 & consi/$ ( a copp] /r&1 coat$ ) gutta-p]*a1 & protect$ f injury by an out] %ea? ( hemp & iron wire4 ,x is ! g5]al type ( all ! subm>9e cables :i* h be5 deposit$ s9ce !n 9 e "p ( ! _w4 ,z a rule1 ! arm\r or %ea?+ is made heavi] = %ore wat] ?an x is = ! deep sea1 b ! electrical portion1 or core1 t is to say1 ! insulat$ conductor1 is ! same ?r\gh\t4 ,! fir/ ,atlantic cable 0 laid 9 #aheh by ,cyrus ,w4 ,field & a company ( ,briti% capitali/s1 b x broke d[n1 & x 0 n until #ahff t a new & successful cable 0 laid to replace x4 ,figure #ea repres5ts v>i\s cross-sections ( an ,atlantic cable deposit$ 9 #ahid4 ,! inn] /> ( twelve copp] wires is ! conductor1 & ! black circle r\nd x is ! gutta-p]*a or insulator :i* keeps ! electricity f escap+ into ! wat]4 ,! core 9 %all[ wat] is protect$ f ! bites ( t]$oes by a brass tape1 & ! envelope or arm\r consi/s ( hemp & iron wire pres]v$ f corrosion by a cov]+ ( tape & a comp\nd ( m9]al pit* & s&4 ,! circuit ( a subm>9e l9e is ess5tially ! same z t ( a l& l9e1 except t ! e>? connection is usually ! iron %ea?+ ( ! cable 9 lieu ( an e>?-plate4 ,on a cable1 h[ev]1 at lea/ a long cable1 ! in/rum5ts = s5d+ & receiv+ ! messages are diff]5t f ^? employ$ on a l& l9e4 ,a cable is virtually a ,leyd5 j> or cond5s]1 & ! signal curr5ts 9 ! wire induce opposite curr5ts 9 ! wat] or e>?4 ,z ^! *>ges hold ea* o!r ! signals are ret>d$ 9 _! progress1 & alt]$ f %>p sudd5 jets to lagg+ undulations or waves1 :i* t5d to run toge!r or coalesce4 ,! result is t ! sep>ate signal curr5ts :i* ent] a long cable issue f x at ! o!r end 9 "o cont9u\s curr5t1 ) pulsations at e signal1 t is to say1 9 a laps+ /ream1 l a jet ( wat] fl[+ f a con/rict$ sp\t4 ,! receiv+ in/rum5t mu/ be suffici5tly delicate to manife/ e pulsation ( ! curr5t4 ,its indicator1 9 fact1 mu/ respond to e rise & fall ( ! curr5t1 z a float rides on ! ripples ( a /ream4 ,su* an in/rum5t is ! beautiful mirror galvanomet] ( ,"l ,kelv91 ,ex-,presid5t ( ! ,royal ,society1 :i* we illu/rate 9 figure #eb1 :]e ,c is a coil ( wire ) a small magnetic ne$le susp5d$ 9 its he>t1 & ,d is a /eel magnet support$ ov] x4 ,! ne$le 7,m figure #ec7 is made ( wat* spr+ cem5t$ to ! back ( a t9y mirror ! size ( a half-dime :i* is hung by a s+le fibre ( floss silk inside an air cell or *amb] ) a glass l5s ,g 9 front1 & ! coil ,c surr\nds x4 ,a ray ( light f a lamp ,l 7figure #eb7 falls on ! mirror1 & is reflect$ back to a scale ,s1 on :i* x makes a bright spot4 ,n[1 :5 ! coil ,c is connect$ betwe5 ! end ( ! cable & ! e>?1 ! signal curr5t pass+ ?r\gh x causes ! t9y magnet to sw+ f side to side1 & ! mirror mov+ ) x ?r[s ! beam up & d[n ! scale4 ,! op]ator sitt+ by wat*es ! spot ( light z x flits & flick]s l a fire-fly 9 ! d>kness1 & spells out ! my/]i\s message4 ,a cond5s] jo9$ 9 ! circuit betwe5 ! cable & ! receiv]1 or betwe5 ! receiv] & ! e>?1 has ! effect ( %>p5+ ! waves ( ! curr5t1 & consequ5tly ( ! signals4 ,! d\ble-curr5t key1 :i* rev]ses ! poles ( ! batt]y & all[s ! signal curr5ts to be ( "o l5g?1 t is to say1 all dots1 is employ$ to s5d ! message4 ,ano!r receiv+ in/rum5t employ$ on mo/ ( ! long] cables is ! siphon record] ( ,"l ,kelv91 %[n 9 figure #ed1 :i* m>ks or writes ! message on a slip ( travell+ pap]4 ,ess5tially x is ! inv]se ( ! mirror in/rum5t1 & consi/s ( a light coil ( wire ,s susp5d$ 9 ! field betwe5 ! poles ( a /rong magnet ,m4 ,! coil is atta*$ to a f9e siphon 7,t#e7 fill$ ) ink1 & sometimes kept 9 vibration by an induction coil s z to %ake ! ink 9 f9e drops ^u a slip ( mov+ pap]4 ,! coil is connect$ betwe5 ! cable & ! e>?1 &1 z ! signal curr5t passes ?r\gh1 x sw+s to "o side or ! o!r1 pull+ ! siphon ) x4 ,! ink1 !re=e1 m>ks a wavy l9e on ! pap]1 :i* is 9 fact a del9eation ( ! rise & fall ( ! signal curr5t & a record ( ! message4 ,! dots 9 ?is case are repres5t$ by ! waves above1 & ! da%es by ! waves bel[ ! middle l9e1 z may be se5 9 ! foll[+ alphabet1 :i* is a copy ( "o actually writt5 by ! record] on a long subm>9e cable4 ,ow+ to induction1 ! spe$ ( signall+ on long cables is mu* sl[] ?an on l& l9es ( ! same l5g?1 & only rea*es f #be to #de words a m9ute on ! ,atlantic cables1 or #cj to #ej words ) an automatic s5d+-key2 b ?is rate is practically d\bl$ by employ+ ! ,muirhead duplex sy/em ( s5d+ two messages1 "o f ea* end1 at ! same "t4 ,! relation ( ! telegraph to ! telephone is analog\s to t ( ! l[] animals & man4 ,9 a telegraph circuit1 ) its click+ key at "o end & its *att]+ s\nd] at ! o!r1 we h1 9 fact1 an api% =]unn] ( ! exquisite telephone1 ) its my/]i\s microphone & oracul> plate4 ,nev]!less1 ! telephone desc5d$ f ! telegraph 9 a v indirect mann]1 if at all1 & c]ta9ly n ?r\gh ! s\nd]4 ,! fir/ practical sugge/ion ( an electric telephone 0 made by ,m4 ,*>les ,b\rseul1 a ,fr5* telegraphi/1 9 #ahed1 b to all appe>ance no?+ came ( x4 ,9 #ahfj1 h[ev]1 ,philipp ,reis1 a ,g]man s*oolma/]1 con/ruct$ a rudim5t>y telephone1 by :i* music & a few spok5 words 7 s5t4 ,f9ally1 9 #ahgf1 ,mr4 ,alex&] ,graham ,bell1 a ,scot*man1 resid+ 9 ,canada1 & subsequ5tly 9 ! ,unit$ ,/ates1 exhibit$ a capable speak+ telephone ( 8 inv5tion at ! ,c5t5nial ,exhibition1 ,philadelphia4 ,figure #ef repres5ts an outside view & section ( ! ,bell telephone z x is n[ made1 :]e ,m is a b> magnet hav+ a small bobb9 or coil ( f9e insulat$ wire ,c girdl+ "o pole4 ,9 front ( ?is coil !re is a circul> plate ( s(t iron capable ( vibrat+ l a diaphragm or ! drum ( ! e>4 ,a cov] %ap$ l a m\?piece ,o fixes ! diaphragm all r\nd1 & ! wires ,w ,w s]ve to connect ! coil 9 ! circuit4 ,! s(t iron diaphragm is1 ( c\rse1 magnetis$ by ! induction ( ! pole1 & w\ld be attract$ bodily to ! pole 7 x n fix$ by ! rim1 s t only its middle is free to move4 ,n[1 :5 a p]son speaks into ! m\?piece ! sonor\s waves imp+e on ! diaphragm & make x vibrate 9 sympa?y ) !m4 ,be+ magnetic1 ! movem5t ( ! diaphragm to & f ! bobb9 excites correspond+ waves ( electricity 9 ! coil1 aft] ! fam\s exp]im5t ( ,f>aday 7page #fd74 ,if ?is undulatory curr5t is pass$ ?r\gh ! coil ( a simil> telephone at ! f> end ( ! l9e1 x w1 by a rev]se action1 set ! diaphragm 9 vibration & reproduce ! orig9al sonor\s waves4 ,! result is1 t :5 ano!r p]son li/5s at ! m\?piece ( ! receiv+ telephone1 he w he> a fai?ful imitation ( ! orig9al spee*4 ,! ,bell telephone is virtually a small magneto-electric g5]ator ( electricity1 & :5 two are jo9$ 9 circuit we h a sy/em = ! transmission ( en]gy4 ,z ! voice is ! motive p[]1 its talk1 ?\gh di/9ct1 is comp>atively feeble1 & fur!r improvem5ts 7 made be=e ! telephone became z s]viceable z x is n[4 ,edison1 9 #ahgg1 0 ! fir/ to inv5t a work+ telephone1 :i*1 in/ead ( g5]at+ ! curr5t1 m]ely controll$ ! /r5g? ( x1 z ! sluice ( a mill-dam regulates ! fl[ ( wat] 9 ! lead4 ,du ,moncel _h obs]v$ t p[d] ( c>bon alt]$ 9 electrical resi/ance "u pressure1 & ,edison f\nd t lamp-black 0 s s5sitive z to *ange 9 resi/ance "u ! impact ( ! sonor\s waves4 ,8 transmitt] consi/$ ( a button or waf] ( lamp-black beh9d a diaphragm1 & connect$ 9 ! circuit4 ,on speak+ to ! diaphragm ! sonor\s waves press$ x aga9/ ! button1 & s v>i$ ! /r5g? ( ! curr5t 9 a sympa!tic mann]4 ,! receiv] ( ,edison 0 equally +5i\s1 & consi/$ ( a cyl9d] ( prep>$ *alk kept 9 rotation & a brass /ylus rubb+ on x4 ,:5 ! undulatory curr5t pass$ f ! /ylus to ! *alk1 ! /ylus slipp$ on ! surface1 &1 be+ connect$ to a diaphragm1 made x vibrate & repeat ! orig9al s\nds4 ,?is electro- motograph receiv] 01 h[ev]1 giv5 up1 & a comb9ation ( ! ,edison transmitt] & ! ,bell receiv] came into use4 ,at ! end ( #ahgg ,pr(essor ,d4 ,e4 ,hughes1 a di/+ui%$ ,wel%man1 inv5tor ( ! pr9t+ telegraph1 discov]$ t any loose contact betwe5 two conductors _h ! prop]ty ( transmitt+ s\nds by v>y+ ! /r5g? ( an electric curr5t pass+ ?r\gh x4 ,two pieces ( metal--= in/ance1 two nails or ends ( wire--:5 br\ght into a loose or crazy contact "u a slight pressure1 & trav]s$ by a curr5t1 w transmit spee*4 ,two pieces ( h>d c>bon are /ill bett] ?an metals1 & if prop]ly adju/$ w make ! tread ( a fly q audible 9 a telephone connect$ ) !m4 ,su* is ! fam\s microphone1 by :i* a fa9t s\nd c be magnifi$ to ! e>4 ,figure #eg repres5ts :at is kn[n z ! p5cil microphone1 9 :i* ,m is a po9t$ rod ( h>d c>bon1 delicately pois$ betwe5 two brackets ( c>bon1 :i* are connect$ 9 circuit ) a batt]y ,b & a ,bell telephone ,t4 ,! jo9ts ( rod & bracket are s s5sitive t ! curr5t fl[+ across !m is affect$ 9 /r5g? by ! slighte/ vibration1 ev5 ! walk+ ( an insect4 ,if1 !re=e1 we speak ne> ?is microphone1 ! sonor\s waves1 caus+ ! p5cil to vibrate1 w s v>y ! curr5t 9 accordance ) !m z to reproduce ! s\nds ( ! voice 9 ! telephone4 ,! true nature ( ! microphone is n yet kn[n1 b x is evid5t t ! air or e!r betwe5 ! surfaces 9 contact plays an important "p 9 v>y+ ! resi/ance1 &1 !re=e1 ! curr5t4 ,9 fact1 a small voltaic arc1 n lum9\s1 b d>k1 seems to be =m$ betwe5 ! po9ts1 & ! vibrations probably alt] its l5g?1 &1 consequ5tly1 its resi/ance4 ,! fact t a microphone is rev]sible & c act z a receiv]1 ?\gh a poor "o1 t5ds to confirm ?is !ory4 ,moreov]1 x is n unlikely t ! slipp+ ( ! /ylus 9 ! electromotograph is due to a simil> cause4 ,be ?is z x may1 !re c be no d\bt t c>bon p[d] & ! lamp-black ( ! ,edison button are ess5tially a clu/] ( microphones4 ,_m v>ieties ( ! ,hughes microphone "u diff]5t names are n[ employ$ z transmitt]s 9 connection ) ! ,bell telephone4 ,figure #eh repres5ts a simple micro-telephone circuit1 :]e ,m is ! ,hughes microphone transmitt]1 ,t ! ,bell telephone receiv]1 ,,jb ! batt]y1 & ,e ,e ! e>?-plates2 b sometimes a return wire is us$ 9 place ( ! e>?4 ,! l9e wire is usually ( copp] & its alloys1 :i* are m suitable ?an iron1 especially = long di/ances4 ,j z ! signal curr5ts 9 a subm>9e cable induce correspond+ curr5ts 9 ! sea wat] :i* ret>d !m1 s ! curr5ts 9 a l& wire induce correspond+ curr5ts 9 ! e>?1 b 9 a]ial l9es ! e>? is g5]ally s f> away t ! consequ5t ret>dation is negligible except 9 fa/ work+ on long l9es4 ,! ,bell telephone1 h[ev]1 is extremely s5sitive1 & ?is induction affects x s mu* t a conv]sation ?r\gh "o wire c be ov]he>d on a neighb\r+ wire4 ,moreov]1 !re is su* a ?+ z self-induction 9 a wire--t is to say1 a curr5t 9 a wire t5ds to induce an opposite curr5t 9 ! same wire1 :i* is practically equival5t to an increase ( resi/ance 9 ! wire4 ,x is p>ticul>ly obs]v$ at ! />t+ & /opp+ ( a curr5t1 & gives rise to :at is call$ ! extra-sp>k se5 9 break+ ! circuit ( an induction coil4 ,x is also active 9 ! vibratory curr5ts ( ! telephone1 &1 l ord9>y induction1 t5ds to ret>d _! passage4 ,copp] be+ less susceptible ( self-induction ?an iron1 is pref]r$ = trunk l9es4 ,! di/urb+ effect ( ord9>y induction is avoid$ by us+ a return wire or loop circuit1 & cross+ ! go+ & com+ wires s z to make !m ex*ange places at int]vals4 ,moreov]1 x is f\nd t an induction coil 9 ! telephone circuit1 l a cond5s] 9 ! cable circuit1 improves ! work+1 & h5ce x is usual to jo9 ! batt]y & transmitt] ) ! prim>y wire1 & ! second>y wire ) ! l9e & ! receiv]4 ,! longe/ telephone l9e z yet made is t f ,new ,york to ,*icago1 a di/ance ( #iej miles4 ,x is made ( ?ick copp] wire1 erect$ on c$> poles #ce feet above ! gr\nd4 ,induction is s /rong on subm>9e cables ( #ej or #ajj miles 9 l5g? t ! delicate waves ( ! telephone curr5t are smoo!d away1 & ! spee* is ei!r muffl$ or entirely /ifl$4 ,nev]!less1 a telephone cable #bj miles long 0 laid betwe5 ,dov] & ,calais 9 #ahia1 & ano!r betwe5 ,/ranra] & ,donaghadee m rec5tly1 ?us plac+ ,great ,brita9 on speak+ t]ms ) ,france & o!r p>ts ( ! ,cont95t4 ,figure #ei %[s a =m ( telephone app>atus employ$ 9 ! ,unit$ ,k+dom4 ,9 x ! transmitt] & receiv]1 toge!r ) a call-bell1 :i* are requir$ at ea* end ( ! l9e1 are neatly comb9$4 ,! transmitt] is a ,blake microphone1 9 :i* ! loose jo9t is a contact ( plat9um on h>d c>bon4 ,x is fitt$ up inside ! box1 toge!r ) an induction coil1 & ,m is ! m\?piece = speak+ to x4 ,! receiv] is a pair ( ,bell telephones ,t ,t1 :i* are deta*$ f _! hooks & held to ! e>4 ,a call-bell ,b s]ves to r+ up ! correspond5t at ! o!r end ( ! l9e4 ,except+ private l9es1 ! telephone is work$ on ! ex*ange sy/em--t is to say1 ! wires runn+ to diff]5t p]sons conv]ge 9 a c5tral ex*ange1 :]e1 by means ( an app>atus call$ a swit* bo>d1 !y are connect$ toge!r = ! purpose ( conv]sation ,a telephone ex*ange w\ld make an excell5t subject = ! arti/4 ,he delights to pa9t u a r[ ( ,v5etian bead /r+]s or a b& ( ,sevilhan cig>ette mak]s1 b :y does he %irk a bevy ( indu/ri\s girls work+ a telephone ex*ange8 ,let u peep into "o ( ^! retir$ haunts1 :]e ! mod]n ,fates are cutt+ & jo9+ ! l9es ( electric spee* betwe5 man & man 9 a great city4 ,! sc5e is a long1 h&some room or gall]y1 ) a s+ul> piece ( furniture 9 ! %ape ( an ,l occupy+ ! middle4 ,?is is ! swit*bo>d1 9 :i* ! wires f ! (fices & homes ( ! subscrib]s are conc5trat$ l ! n]ves 9 a ganglion4 ,x is kn[n z ! multiple swit*bo>d1 an ,am]ican inv5tion1 & is divid$ into sections1 ov] :i* ! op]ators preside4 ,! l9es ( all ! subscrib]s are br\ght to ea* section1 s t ! op]ator c cross connect any two l9es 9 ! :ole sy/em )\t leav+ h] *air4 ,ea* section ( ! bo>d is1 9 fact1 an epitome ( ! :ole1 b x is physically impossible = a s+le op]ator to make all ! connections ( a l>ge ex*ange1 & ! "w is di/ribut$ among/ !m4 ,a multiplicity ( wires is !re=e ne$$ to connect1 say1 two ?\s& subscrib]s4 ,^! are all conceal$1 h[ev]1 at ! back ( ! bo>d1 & 9 *>ge ( ! electricians4 ,! "y lady op]ators h no?+ to d ) ^!1 & s mu* ! bett] = !m1 z x w\ld puzzle _! m9ds a good deal worse ?an a ravell$ ske9 ( ?read4 ,_! duty is to sit 9 front ( ! bo>d 9 com=table seats at a long table & make ! ne$ful connections4 ,! call signal ( a subscrib] is giv5 by ! drop ( a disc be>+ 8 numb]4 ,! op]ator !n asks ! subscrib] by telephone :at he wants1 & on he>+ ! numb] ( ! o!r subscrib] he wi%es to speak )1 %e takes up a pair ( brass plugs c\pl$ by a flexible conductor & jo9s ! l9es ( ! subscrib]s on ! swit*bo>d by simply ?ru/+ ! plugs into holes correspond+ to ! wires4 ,! subscrib]s are !n free to talk ) ea* o!r undi/urb$1 & ! end ( ! conv]sation is signall$ to ! op]ator4 ,e in/ant ! call discs are dropp+1 ! connect+ plugs are ?ru/ into ! holes1 & ! girls are ask+ ,hullo6 hullo6 ,are y !re8 ,:o are y8 ,h y f9i%$8 ,yet all ?is con/ant activity goes on quietly1 deftly --we might say elegantly--& 9 comp>ative sil5ce1 = ! l[ tones ( ! girli% voices are s(t & pleas+1 & ! h>%] s\nds ( ! subscrib] are unhe>d 9 ! room by all save ! op]ator :o att5ds to him4 ,,*apt] ,,vii4 ,,electric ,,light ,,& ,,heat4 ,! electric sp>k 01 ( c\rse1 famili> to ! e>ly exp]im5t]s ) electricity1 b ! electric light1 z we "k x1 0 fir/ discov]$ by ,sir ,humphrey ,davy1 ! ,corni% philosoph]1 9 ! ye> #ahaa or !reab\t4 ,) ! magic ( 8 g5ius ,davy trans=m$ ! sp>k into a brilliant gl[ by pass+ x betwe5 two po9ts ( c>bon in/ead ( metal4 ,if1 z 9 figure #fj1 we twi/ ! wires 7 &--7 :i* come f a voltaic batt]y1 say ( #bj cells1 ab\t two c>bon p5cils1 & br+ _! tips toge!r 9 ord] to />t ! curr5t1 !n draw !m a little ap>t1 we %all produce an artificial or mimic />4 ,a %eet ( dazzl+ light1 :i* is call$ ! electric arc1 is se5 to bridge ! gap4 ,x is n a true flame1 = !re is little combu/ion1 b r a nebul\s blaze ( silv]y lu/re 9 a blui% veil ( heat$ air4 ,! po9ts ( c>bon are :ite-hot1 & ! positive is eat5 away into a holl[ or crat] by ! curr5t1 :i* viol5tly te>s its p>ticles f _! seat & :irls !m into ! fi]ce vortex ( ! arc4 ,! negative rema9s po9t$1 b x is also worn away ab\t half z fa/ z ! positive4 ,?is wa/+ ( ! c>bons t5ds to wid5 ! arc too mu* & break ! curr5t1 h5ce 9 arc lamps meant to yield ! light = h\rs ! /icks are made ( a good l5g?1 & a self- act+ me*anism fe$s !m =w>d to ! arc z !y are sl[ly consum$1 ?us ma9ta9+ ! spl5d\r ( ! illum9ation4 ,_m +5i\s lamps h be5 devis$ by ,s]r91 ,dubosq1 ,siem5s1 ,brockie1 & o!rs1 "s regulat+ ! arc by clockwork & electro-magnetism1 or by !rmal & o!r effects ( ! curr5t4 ,!y are *iefly us$ = light+ halls & railway /ations1 /reets & op5 spaces1 se>*-lights & ligh?\ses4 ,!y are sometimes nak$1 b z a rule _! brightness is temp]$ by globes ( gr\nd or opal glass4 ,9 se>*-lights a p>abolic mirror projects all ! rays 9 any "o direction1 & 9 ligh?\ses ! arc is plac$ 9 ! focus ( ! cond5s+ l5ses1 & ! beam is visible = at lea/ tw5ty or ?irty miles on cle> nights4 ,v p[]ful arc lights1 equival5t to hundr$s ( ?\s&s ( c&les1 c be se5 = #ajj or #aej miles4 ,figure #fa illu/rates ! ,pils5 lamp1 9 :i* ! positive ,c>bon ,g runs on roll]s rr ?r\gh ! holl[ int]ior ( two sol5oids or coils ( wire ,,mm' & c>ries at its middle a sp9dle-%ap$ piece ( s(t iron ,c4 ,! curr5t fl[s ?r\gh ! sol5oid ,m on its way to ! arc1 b a bran* or %unt$ portion ( x fl[s ?r\gh ! sol5oid ,m'1 & z bo? ( ^! sol5oids act z electromagnets on ! s(t iron ,c1 ea* t5d+ to suck x into its int]ior1 ! iron re/s betwe5 !m :5 _! p[]s are balanc$4 ,:51 h[ev]1 ! arc gr[s too wide1 & ! curr5t !re=e becomes too weak1 ! %unt sol5oid ,m' ga9s a pur*ase ov] ! ma9 sol5oid ,m1 &1 pull+ ! iron core t[>ds x1 fe$s ! positive c>bon to ! arc4 ,9 ?is way ! balance ( ! sol5oids is readju/$1 ! curr5t rega9s its normal /r5g?1 ! arc its prop] wid?1 & ! light its brilliancy4 ,figure #fb is a diagrammatic repres5tation ( ! ,bru% arc lamp4 ,x & ,y are ! l9e t]m9als connect+ ! lamp 9 circuit4 ,on ! "o h&1 ! curr5t splits & passes ar\nd ! holl[ spools ,h ,h'1 !nce to ! rod ,n ?r\gh ! c>bon ,k1 ! arc1 ! c>bon ,k'1 & !nce ?r\gh ! lamp frame to ,y4 ,on ! o!r h&1 x runs 9 a resi/ance f9e-wire coil ar\nd ! magnet ,t1 !nce to ,y4 ,! op]ation ( ! lamp is z foll[s3 ,k & ,k' be+ 9 contact1 a /rong curr5t />ts ?r\gh ! lamp en]gis+ ,h & ,h'1 :i* suck 9 _! core pieces ,n & ,s1 lift+ ,c1 & by x ! wa%]-clut* ,w & ! rod ,n & c>bon ,k1 e/abli%+ ! arc4 ,k is lift$ until ! increas+ resi/ance ( ! l5g!n+ arc weak5s ! curr5t 9 ,h ,h' & a balance is e/abli%$4 ,z ! c>bons burn away1 ,c gradually l[]s until a /op "u ,w holds x horizontal & all[s ,n to drop ?r\gh ,w1 & ! lamp />ts anew4 ,if = any reason ! resi/ance ( ! lamp becomes too great1 or ! circuit is brok51 ! increas$ curr5t ?r\gh ,t draws up its armature1 clos+ ! contacts ,m1 ?us %ort-circuit+ ! lamp ?r\gh a ?ick1 heavy wire coil on ,t1 :i* !n keeps ,m clos$1 & prev5ts ! dead lamp f int]f]+ ) ! o!rs on its l9e4 ,num]\s modifications ( ?is lamp are 9 v g5]al use4 ,davy also f\nd t a cont9u\s wire or /ick ( c>bon c\ld be made :ite-hot by s5d+ a suffici5t curr5t ?r\gh x1 & ?is fact is ! basis ( ! inc&esc5t lamp n[ s common 9 our homes4 ,wires ( plat9um1 iridium1 & o!r inoxidisable metals rais$ to inc&esc5ce by ! curr5t are useful 9 fir+ m9es1 b !y are n q suitable = yield+ a light1 because at a v high temp]ature !y beg9 to melt4 ,e solid body becomes r$-hot--t is to say1 emits rays ( r$ light1 at a temp]ature ( ab\t #ajjj degrees ,fahr5heit1 yell[ rays at #acjj degrees1 blue rays at #aejj degrees1 & :ite light at #bjjj degrees4 ,x is f\nd1 h[ev]1 t z ! temp]ature ( a wire is pu%$ beyond ?is figure ! light emitt$ becomes f> m brilliant ?an ! increase ( temp]ature w\ld seem to w>rant4 ,x !re=e pays to elevate ! temp]ature ( ! filam5t z high z possible4 ,un=tunately ! mo/ refractory metals1 su* z plat9um & alloys ( plat9um ) iridium1 fuse at a temp]ature ( ab\t #cdej degrees ,fahr5heit4 ,electricians h !re=e =sak5 metals1 & fall5 back on c>bon = produc+ a light4 ,9 #ahde ,mr4 ,/aite devis$ an inc&esc5t lamp consi/+ ( a f9e rod or /ick ( c>bon r5d]$ :ite-hot by ! curr5t1 & to pres]ve ! c>bon f burn+ 9 ! atmosph]e1 he enclos$ x 9 a glass bulb1 f :i* ! air 0 exhau/$ by an air pump4 ,edison & ,swan1 9 #ahgh1 & subsequ5tly1 w5t a /ep fur!r1 & sub/itut$ a filam5t or f9e ?read ( c>bon = ! rod4 ,! new lamp unit$ ! advantages ( wire 9 po9t ( =m ) ^? ( c>bon z a mat]ial4 ,! ,edison filam5t 0 made by cutt+ ?9 slips ( bamboo & *>r+ !m1 ! ,swan by c>bonis+ l95 fibre ) sulphuric acid4 ,x 0 subsequ5tly f\nd t a h>d sk9 c\ld be giv5 to ! filam5t by fla%+ x--t is to say1 heat+ x to inc&esc5ce by ! curr5t 9 an atmosph]e ( hydroc>bon gas4 ,! filam5t ?us treat$ becomes d5se & resili5t4 ,figure #fc repres5ts an ord9>y gl[ lamp ( ! ,edison-,swan type1 :]e ,e is ! filam5t1 m\ld$ into a loop1 & cem5t$ to two plat9um wires or electrodes ,p p5etrat+ ! glass bulb ,l1 :i* is exhau/$ ( air4 ,plat9um is *os5 because x exp&s & contracts ) temp]ature ab\t ! same z glass1 & h5ce !re is little *ance ( ! glass crack+ ?r\gh unequal /ress4 ,! vacuum 9 ! bulb is made by a m]curial air pump ( ! ,spr5gel sort1 & ! pressure ( air 9 x is only ab\t "o-million? ( an atmosph]e4 ,! bulb is fa/5$ ) a hold] l t %[n 9 figure #fd1 :]e two little hooks ,h connect$ to screw t]m9als ,t ,t are provid$ to make contact ) ! plat9um t]m9als ( ! lamp 7,p1 figure #fc71 & ! spiral spr+1 by press+ on ! bulb1 ensures a good contact4 ,fig4 #fe is a cut ( ! ord9>y ,edison lamp & socket4 ,"o end ( ! filam5t is connect$ to ! metal screw f]ule at ! base4 ,! o!r end is atta*$ to ! metal button 9 ! c5tre ( ! extreme bottom ( ! base4 ,screw+ ! lamp into ! socket automatically connects ! filam5t on "o end to ! screw1 on ! o!r to an insulat$ plate at ! bottom ( ! socket4 ,! resi/ance ( su* a filam5t hot is ab\t #bjj ohms1 & to produce a good light f x ! batt]y or dynamo ought to give an electromotive =ce ( at lea/ #ajj volts4 ,few voltaic cells or accumulators h an electromotive =ce ( m ?an #b volts1 !re=e we require a batt]y ( #ej cells jo9$ 9 s]ies1 ea* cell giv+ #b volts1 & ! :ole set #ajj volts4 ,! /r5g? ( curr5t 9 ! circuit mu/ also be tak5 into acc\nt4 ,to yield a good light su* a lamp requires or takes ab\t #a_/b an amp]e4 ,h5ce ! cells mu/ be *os5 ) reg>d to _! size & int]nal resi/ance z well z to _! k9d1 s t :5 ! batt]y1 9 s]ies1 is connect$ to ! lamp1 ! resi/ance ( ! :ole circuit1 includ+ ! filam5t or lamp1 ! batt]y itself1 & ! connect+ wires %all give by ,ohm's law a curr5t ( #ab an amp]e4 ,x w be und]/ood t ! curr5t has ! same /r5g? 9 e "p ( ! circuit1 no matt] h[ x is made up4 ,?us1 if #a_/b ( an amp]e is fl[+ 9 ! lamp1 x is also fl[+ 9 ! batt]y & wires4 ,an ,edison-,swan lamp ( ?is model gives a light ( ab\t #ae c&les1 & is well adapt$ = illum9at+ ! int]ior ( h\ses4 ,! temp]ature ( ! c>bon filam5t is ab\t #cdej degrees ,fahr--t is to say1 ! temp]ature at :i* plat9um melts4 ,simil> lamps ( v>i\s sizes & %apes are also made1 "s equival5t to z _m z #ajj c&les1 & fitt$ = l>ge halls or /reets1 o!rs emitt+ a t9y beam l ! sp>k ( a gl[-worm1 & design$ = m$ical exam9ations1 or light+ fl[]s1 jewels1 & dresses 9 !atres or ball-rooms4 ,! electric inc&esc5t lamp is pure & heal?y1 s9ce x nei!r burns nor pollutes ! air4 ,x is also cool & safe1 = x produces little heat1 & _c ignite any inflammable /uffs ne> x4 ,h5ce its peculi> m]it z a light = colli]s work+ 9 fi]y m9es4 ,indep5d5t ( air1 x acts equally well "u wat]1 & is !re=e us$ by div]s4 ,moreov]1 x c be fix$ :]ev] a wire c be run1 does n t>ni% gild+1 & l5ds itself to ! mo/ arti/ic decoration4 ,electric lamps are usually connect$ 9 circuit on ! s]ies1 p>allel1 & ?ree wire sy/em4 ,! s]ies sy/em is %[n 9 figure #ff1 :]e ! lamps ,l ,l foll[ ea* o!r 9 a r[ l beads on a /r+4 ,x is commonly res]v$ = ! arc lamp1 :i* has a resi/ance s l[ t a mod]ate electromotive =ce c ov]come ! add$ resi/ance ( ! lamps1 b1 ( c\rse1 if ! circuit breaks at any po9t all ! lamps g out4 ,! p>allel sy/em is illu/rat$ 9 figure #fg1 :]e ! lamps are connect$ betwe5 two ma9 conductors cross-wise1 l ! /eps ( a ladd]4 ,! curr5t is ?us divid$ into cross *annels1 l wat] us$ = irrigat+ fields1 & x is obvi\s t1 al?\gh ! circuit is brok5 at "o po9t1 say by ! rupture ( a filam5t1 all ! lamps d n g out4 ,fig4 #fh exhibits ! ,edison ?ree-wire sy/em1 9 :i* two batt]ies or dynamos are connect$ toge!r 9 s]ies1 & a ?ird or c5tral ma9 conductor is run f _! middle poles4 ,! plan saves a return wire1 = if two g5]ators _h be5 us$ sep>ately1 f\r ma9s w\ld h be5 necess>y4 ,! p>allel & ?ree-wire sy/ems 9 v>i\s gr\ps1 ) or )\t accumulators z local res]voirs1 are *iefly employ$ = inc&esc5t lamps4 ,! ma9 conductors convey+ ! curr5t f ! dynamos are commonly ( /\t copp] insulat$ ) air l telegraph wires1 or cables coat$ ) india-rubb] or gutta-p]*a1 & buri$ und]gr\nd or susp5d$ ov]head4 ,! bran* & lamp conductors or leads are f9] wires ( copp]1 insulat$ ) india-rubb] or silk4 ,! curr5t ( an in/allation or section ( "o is made & brok5 at w by means ( a swit* or key turn$ by h&4 ,x is simply a s]ies ( metal contacts insulat$ f ea* o!r & connect$ to ! conductors1 ) a slid+ contact connect$ to ! dynamo :i* travels ov] !m4 ,to gu>d aga9/ an excess ( curr5t on ! lamps1 cut-outs1 or safety-fuses1 are ins]t$ betwe5 ! swit* & ! conductors1 or at o!r lead+ po9ts 9 ! circuit4 ,!y are usually made ( %ort slips ( metal foil or wire1 :i* melt or deflagrate :5 ! curr5t is too /rong1 & ?us int]rupt ! circuit4 ,!re is "s prospect ( ! lum9osity excit$ 9 a vacuum tube by ! alt]nat+ curr5ts f a dynamo or an induction coil becom+ an illum9ant4 ,crookes has obta9$ exquisitely beautiful gl[s by ! phosphoresc5ce ( gems & o!r m9]als 9 a vacuum bulb l t %[n 9 figure #fi1 :]e ,a & ,b are ! metal electrodes on ! outside ( ! glass4 ,a heap ( diamonds f v>i\s c\ntries emit r$1 orange1 yell[1 gre51 & blue rays4 ,ruby1 sapphire1 & em]ald give a deep r$1 crimson1 or lilac phosphoresc5ce1 & sulphate ( z9c a magnific5t gre5 gl[4 ,tesla has also %[n t vacuum bulbs c be lit inside )\t any outside connection ) ! curr5t1 by means ( an app>atus l t %[n 9 figure #gj1 :]e ,d is an alt]nat+ dynamo1 ,c a cond5s]1 ,p ,s ! prim>y & second>y coils ( a sp>k+ trans=m]1 ,t ,t two metal %eets or plates1 & ,,sb ! exhau/$ bulbs4 ,! alt]nat+ or see-saw curr5t 9 ?is case *>ges ! cond5s] & excites ! prim>y coil ,p1 :ile ! induc$ curr5t 9 ! second>y coil #e *>ges ! t]m9al plates ,t ,t4 ,s long z ! bulbs or tubes are kept )9 ! space betwe5 ! plates1 !y are fill$ ) a s(t radiance1 & x is easy to see t if ^! plates cov]$ ! opposite walls ( a room1 ! vacuum lamps w\ld yield a light 9 any "p ( x4 ,electric heat+ bids fair to become almo/ z important z electric illum9ation4 ,:5 ! arc 0 fir/ discov]$ x 0 notic$ t plat9um1 gold1 qu>tz1 ruby1 & diamond--9 f9e1 ! mo/ refractory m9]als--7 melt$ 9 x1 & ran l wax4 ,ores & salts ( ! metals 7 also vap\ris$1 & x 0 cle> t a p[]ful eng9e ( rese>* _h be5 plac$ 9 ! h&s ( ! *emi/4 ,z a matt] ( fact1 ! temp]ature ( ! c>bons 9 ! arc is comp>able to t ( ! ,sun4 ,x measures #ejjj to #aj1jjj degrees ,fahr5heit1 & is ! highe/ artificial heat kn[n4 ,sir ,william ,siem5s 0 among ! fir/ to make an electric furnace heat$ by ! arc1 :i* fus$ & vap\ris$ metallic ores1 s t ! metal c\ld be extract$ f !m4 ,alum9ium1 *romium1 & o!r valuable metals are n[ smelt$ by its means1 & r\gh brilliants su* z ^? f\nd 9 diamond m9es & meteoric /ones h be5 cry/allis$ f ! fumes ( c>bon1 l ho> fro/ 9 a cold mi/4 ,! electric arc is also appli$ to ! weld+ ( wires1 boil] plates1 rails1 & o!r metal "w1 by heat+ ! p>ts to be jo9$ & fus+ !m toge!r4 ,cook+ & heat+ by electricity are com+ m & m into fav\r1 ow+ to _! cleanl9ess & conv5i5ce4 ,kit*5 ranges1 includ+ ov5s & grills1 entirely heat$ by ! electric curr5t1 are f9d+ _! way into ! be/ h\ses & hotels4 ,mo/ ( ^! are bas$ on ! pr9ciple ( inc&esc5ce1 ! curr5t heat+ a f9e wire or o!r conductor ( high resi/ance 9 pass+ ?r\gh x4 ,figure #ga repres5ts an electric kettle ( ?is sort1 :i* requires no outside fire to boil x1 s9ce ! curr5t fl[s ?r\gh f9e wires ( plat9um or "s highly resi/+ metal emb$d$ 9 firepro( insulat+ cem5t 9 its bottom4 ,figures #gb & #gc are a sauce-pan & a flat-iron heat$ 9 ! same way4 ,figure #gd is a cig>-light] = smok+ rooms1 ! fusee ,f consi/+ ( %ort plat9um wires1 :i* become r$-hot :5 x is unhook$1 & at ! same "t ! lamp ,z is automatically lit4 ,figure #ge is an electric radiator = heat+ rooms & passages1 aft] ! mann] ( /oves & hot wat] pipes4 ,quilts = b$s1 w>m$ by f9e wires inside1 h also be5 br\ght out1 a con/ant temp]ature be+ ma9ta9$ by a simple regulator1 & x is n unlikely t p]sonal clo?+ ( ! k9d w soon be at ! s]vice ( invalids & *illy mortals1 m especially to make !m com=table on _! travels4 ,an +5i\s device places an electric heat] inside a hot wat] bag1 ?us keep+ x at a uni=m temp]ature = sick-room & hospital use4 ,,*apt] ,,viii4 ,,electric ,,p[]4 ,on ! discov]y ( electromagnetism 7,*ap4 ,,iv471 ,f>aday1 ,b>l[1 & o!rs devis$ exp]im5tal app>atus = produc+ rot>y motion f ! electric curr5t1 & 9 #ahca1 ,joseph ,h5ry1 ! fam\s ,am]ican electrician1 inv5t$ a small electromagnetic eng9e or motor4 ,^! e>ly ma*9es 7 actuat$ by ! curr5t f a voltaic batt]y1 b 9 ! middle ( ! c5tury ,jacobi f\nd t a dynamo-electric g5]ator c also "w z a motor1 & t by c\pl+ two dynamos 9 circuit--"o z a g5]ator1 ! o!r z a motor--x 0 possible to transmit me*anical p[] to any di/ance by means ( electricity4 ,figure #gf is a diagram ( a simple circuit = ! transmission ( p[]1 :]e ,d is ! te*nical symbol = a dynamo z a g5]ator1 hav+ its poles 7 & -7 connect$ by wire to ! poles ( ,m1 ! di/ant dynamo1 z a motor4 ,! g5]ator ,d is driv5 by me*anical en]gy f any conv5i5t s\rce1 & trans=ms x into electric en]gy1 :i* fl[s ?r\gh ! circuit 9 ! direction ( ! arr[s1 &1 9 trav]s+ ! motor ,m1 is re-trans=m$ into me*anical en]gy4 ,!re is1 ( c\rse1 a c]ta9 wa/e ( en]gy 9 ! process1 b ) good ma*9es & conductors1 x is n m ?an #aj to #be p] c5t41 or ! effici5cy ( ! in/allation is f #ge to #ij p] c5t--t is to say1 = e #ajj horse-p[] put into ! g5]ator1 f #ge to #ij horse-p[] are giv5 out aga9 by ! motor4 ,x 0 n until #ahgj1 :5 ,gramme _h improv$ ! dynamo1 t p[] 0 practically transmitt$ 9 ?is way1 & appli$ to pump+ wat]1 & o!r "w4 ,s9ce !n great progress has be5 made1 & electricity is n[ recognis$1 n only z a rival ( /eam1 b z ! be/ means ( di/ribut+ /eam1 w9d1 wat]1 or any o!r p[] to a di/ance1 & br++ x to be> on ! prop] po9t4 ,! fir/ electric railway1 or1 r1 tramway1 0 built by ,dr4 ,w]n] von ,siem5s at ,b]l9 9 #ahgi1 & 0 soon foll[$ by _m o!rs4 ,! :eels ( ! c> 7 driv5 by an electric motor draw+ its electricity f ! rails1 :i* 7 insulat$ f ! gr\nd1 & be+ connect$ to ! g5]ator1 s]v$ z conductors4 ,x 0 f\nd v difficult to insulate ! rails1 & keep ! electricity f leak+ to ! gr\nd1 h[ev]1 & at ! ,pans ,electrical ,exhibition ( #ahha1 von ,siem5s made a %ort tramway 9 :i* ! curr5t 0 drawn f a b>e copp] conductor runn+ on poles1 l a telegraph wire1 along ! l9e4 ,! sy/em w be und]/ood f figure #gg1 :]e ,l is ! ov]head conductor jo9$ to ! positive pole ( ! dynamo or g5]ator 9 ! p[] h\se1 & ,c is a roll+ contact or trolley :eel travell+ ) ! c> & connect$ by ! wire ,w to an electric motor ,m "u ! c>1 & ge>$ to ! axles4 ,aft] pass+ ?r\gh ! motor ! curr5t escapes to ! rail ,r by a bru% or slid+ contact ,c'1 & s returns to ! negative pole ( ! g5]ator4 ,a v g5]al way is to all[ ! return curr5t to escape to ! rails ?r\gh ! :eels4 ,_m tramways1 cov]+ ?\s&s ( miles1 are n[ work$ on ?is plan 9 ! ,unit$ ,/ates4 ,at ,bangor1 ,ma9e1 a modification ( x is 9 use :]eby ! conductor is divid$ into sections1 alt]nately connect$ to ! positive & negative poles ( two g5]ators1 c\pl$ toge!r z 9 ! ?ree-wire sy/em ( electric light+ 7page #aai71 _! middle poles be+ jo9$ to ! e>? --t is to say1 ! rails4 ,x enables two c>s to be run on ! same l9e at once1 & ) a consid]able sav+ ( copp]4 ,to make ! c> indep5d5t ( ! conductor ,l = a %ort "t1 z 9 swit*+1 a batt]y ( accumulators ,b may be add$ & *>g$ f ! conductor1 s t :5 ! motor is disconnect$ f ! conductor1 ! dis*>ge f ! accumulator may /ill "w x & drive ! :eels4 ,attempts h be5 made to run tramc>s ) ! electricity suppli$ by accumulators alone1 b ! sy/em is n economical ow+ to ! dead weight ( ! cells1 & ! p]iodical tr\ble ( re*>g+ !m at ! g5]at+ /ation4 ,on heavy railroads work$ by electricity ! ov]head conductor is replac$ by a ?ird rail along ! middle ( ! track1 & insulat$ f ! gr\nd ,9 ano!r sy/em ! middle conductor is buri$ und]gr\nd1 & ! curr5t is tapp$ at int]vals by ! motor connect+ ) x = a mom5t by means ( spr+ contacts z ! c> travels ,9 ea* case1 h[ev]1 ! out] rails s]ve z ! return conductors ,ano!r sy/em puts "o or bo? ! conductors 9 a conduit und]gr\nd1 ! trolley pole ent]+ ?r\gh a n>r[ slot simil> to t us$ on cable roads ,! fir/ electric c>riages = ord9>y roads 7 con/ruct$ 9 #ahhi by ,mr4 ,magnus ,volk ( ,brighton4 ,figure #gh repres5ts "o ( ^! made = ! ,sultan ( ,turkey1 & propell$ by a "o- horse-p[] ,immis* electric motor1 ge>$ to "o ( ! h9d :eels by means ( a *a94 ,! curr5t = ! motor 0 suppli$ by ?irty ,,eps accumulators /[$ 9 ! body ( ! vehicle1 & ( suffici5t p[] to give a spe$ ( t5 miles an h\r4 ,! driv] /e]s ) a h& lev] z %[n1 & controls ! spe$ by a swit* 9 front ( him4 ,vans1 ba? *airs1 & tricycles are also driv5 by electric motors1 b ! weight ( ! batt]y is a drawback to _! use4 ,9 or ab\t ! ye> #ahci1 ,jacobi sail$ an electric boat on ! ,neva1 ) ! help ( an electromagnetic eng9e ( "o horse- p[]1 f$ by ! curr5t f a batt]y ( ,grove cells1 & 9 #ahhb a screw laun*1 c>ry+ sev]al pass5g]s1 & propell$ by an electric motor ( ?ree horse-p[]1 work$ by =ty-five accumulators1 0 tri$ on ! ,?ames4 ,be+ sil5t & smokeless 9 its action1 ! electric boat soon came into fav\r1 & !re is n[ q a flotilla on ! riv]1 ) p[] /ations = *>g+ ! accumulators at v>i\s po9ts along ! banks4 ,figure #gi illu/rates ! int]ior ( a h&some electric laun*1 ! ,lady ,coop]1 built = ! ,e ,p ,s1 or ,electric ,p[] ,/orage ,company4 ,an electric motor 9 ! aft] "p ( ! hull is c\pl$ directly to ! %aft ( ! screw propell]1 & f$ by ,e ,p ,s accumulators 9 teak boxes lodg$ "u ! deck amid%ips4 ,! screw is controll$ by a swit*1 & ! rudd] by an ord9>y helm4 ,! cab9 is sev5 feet long1 & light$ by electric lamps4 ,al>m signals are giv5 by an electric gong1 & a se>*-light c be br\ght into op]ation :5ev] x is desirable4 ,! spe$ atta9$ by ! ,lady ,coop] is f t5 to fifte5 knots4 ,m4 ,g\bet1 a ,fr5*man1 has con/ruct$ a subm>9e boat = dis*>g+ torp$oes & explor+ ! sea bottom1 :i* is propell$ by a screw & an electric motor f$ by accumulators4 ,x c travel entirely "u wat]1 bel[ ! agitation ( ! waves1 :]e sea-sickness is impossible1 & ! inv5tor hopes t vessels ( ! k9d w yet c>ry pass5g]s across ! ,*annel4 ,! screw propell] ( ! ,edison & ,sim's torp$o is also driv5 by an electric motor4 ,9 ?is case ! curr5t is convey$ f ! %ip or =t :i* dis*>ges ! torp$o by an insulat$ conductor runn+ (f a reel c>ri$ by ! torp$o1 ! e>? or return half ( ! circuit be+ ! sea-wat]4 ,all sorts ( ma*9]y are n[ work$ by ! electric motor--= in/ance1 cranes1 elevators1 cap/ans1 rivett]s1 la!s1 pumps1 *aff-cutt]s1 & saws4 ,( dome/ic appliances1 figure #hj %[s an air propell] or v5tilation fan1 :]e ,f is a screw-l fan atta*$ to ! sp9dle ( ! motor ,m1 & revolv+ ) its armature4 ,figure #ha repres5ts a ,tr\ve motor work+ a sew+- ma*9e1 :]e ,n is ! motor :i* ge>s ) ,p ! driv+ axle ( ! ma*9e4 ,figure #hb repres5ts a f9e drill actuat$ by a ,griscom motor4 ,! motor ,m is susp5d$ f a bracket ,a ,b ,c by ! tackle ,d ,e1 & transmits ! rotation ( its armature by a flexible %aft ,s ,t to ! t]m9al drill ,o1 :i* c be appli$ at any po9t1 & is useful 9 bor+ tee?4 ,n[ t electricity is manufactur$ & di/ribut$ 9 t[ns & villages = ! electric light1 x is m & m employ$ = driv+ ! light] ma*9]y4 ,/eam1 h[ev]1 is m economical on a l>ge scale1 & /ill cont9ues to be us$ 9 great factories = ! heavi] ma*9]y4 ,nev]!less a day is com+ :5 coal1 in/ead ( be+ c>ri$ by rail to di/ant works & cities1 w be burn$ at ! pit m\?1 & its heat trans=m$ by means ( eng9es & dynamos into electricity = di/ribution to ! surr\nd+ c\ntry4 ,i h %[n else:]e t peat c be utilis$ 9 a simil> mann]1 & h[ ! great ,bog ( ,all5 is virtually a neglect$ gold field 9 ! he>t ( ,irel&4 ,footnote3 ,! ,n9ete5? ,c5tury = ,decemb] #ahid4 ,! sun%9e ( des]ts1 & p]haps ! electricity ( ! atmosph]e1 b at all ev5ts ! p[] ( w9ds1 waves1 & wat]falls are also de/9$ to :irl ! dynamo1 & yield u light1 heat1 or motion4 ,mu* has already be5 done 9 ?is direction4 ,9 #ahia ! p[] ( turb9es driv5 by ! ,falls ( ,neck> at ,lauff5 0 trans=m$ into electricity1 & transmitt$ by a small wire to ! ,electrical ,exhibition ( ,frank=t-on-!-,ma91 #aag miles away4 ,! city ( ,rome is n[ light$ f ! ,falls ( ,tivoli1 #af miles di/ant4 ,! f9e/ cat>act 9 ,great ,brita91 ! ,falls ( ,foy]s1 9 ! ,highl&s1 :i* p]sons ( ta/e & culture wi%$ to pres]ve = ! nation1 is be+ sacrific$ to ! _s ( trade1 & depriv$ ( its wat]s = ! purpose ( g5]at+ electricity to r$uce alum9ium f its ores4 ,! great s*eme rec5tly complet$ = utiliz+ ! p[] ( ,niag>a ,falls by means ( electricity is a triumph ( human ent]prise :i* outrivals "s ( ! bold creations ( ,jules ,v]ne4 ,:5 9 #afgh ! ,fr5* mission>ies ,la ,salle & ,h5nep9 discov]$ ! /up5d\s cat>act on ! ,niag>a ,riv] betwe5 ,lake ,ont>io & ,lake ,erie1 ! sci5ce ( electricity 0 9 its e>ly infancy1 & little m 0 kn[n ab\t ! my/]i\s =ce :i* is p]=m+ miracles 9 our day ?an its manife/ation on rubb$ amb]1 seal+-wax1 glass1 & o!r bodies4 ,ne>ly a hundr$ ye>s _h /ill to pass ere ,frankl9 %\ld demon/rate ! id5tity ( ! electric fire ) lightn+1 & ne>ly ano!r hundr$ be=e ,f>aday %\ld reveal a mode ( g5]at+ x f me*anical p[]4 ,assur$ly1 nei!r ,la ,salle nor 8 contempor>ies ev] dream$ ( a "t :5 ! wat]-p[] ( ! ,falls w\ld be di/ribut$ by means ( electricity to produce light or heat & s]ve all mann] ( indu/ries 9 ! surr\nd+ di/rict4 ,! awe/ruck ,iroquois ,indians _h nam$ ! cat>act ,oniagahra1 or ,?und] ( ! ,wat]s1 & believ$ x ! dwell+-place ( ! ,_s ( ,?und]4 ,?is poetical "n is none ! less appropriate n[ t ! mod]n electrician is prep>+ to draw 8 lightn+s f its wat]s & compel ! g5ius loci to become 8 will+ bondsman4 ,! ,falls ( ,niag>a are situat$ ab\t tw5ty-"o miles f ,lake ,erie1 & f\rte5 miles f ,lake ,ont>io4 ,at ?is po9t ! ,niag>a ,riv]1 ne>ly a mile broad1 fl[+ betwe5 level banks1 & p>t$ by sev]al isl&s1 is sudd5ly %ot ov] a precipice #agj feet high1 & mak+ a %>p b5d to ! nor?1 pursues its c\rse ?r\gh a n>r[ gorge t[>ds ,lake ,ont>io4 ,! ,falls are divid$ at ! br9k by ,goat ,isl&1 ^: primeval woods are /ill ?riv+ 9 _! spray4 ,! ,horse%oe ,fall on ! ,canadian side is #hab y>ds1 & ! ,am]ican ,falls on ! s\? side are #cbe y>ds wide4 ,= a consid]able di/ance bo? above & bel[ ! ,falls ! riv] is turbul5t ) rapids4 ,! wat]-p[] ( ! cat>act has be5 employ$ f old5 times4 ,! ,fr5* fur-trad]s plac$ a mill beside ! upp] rapids1 & ! e>ly ,briti% settl]s built ano!r to saw ! timh] us$ 9 _! /ockades4 ,by-&-by1 ! ,/$man & ,port] mills 7 e/abli%$ bel[ ! ,falls2 & subsequ5tly1 o!rs :i* d]iv$ _! wat]-supply f ! l[] rapids by means ( raceways or leads4 ,ev5tually1 an op5 hydraulic canal1 ?ree- f\r?s ( a mile long1 0 cut across ! elb[ ( l& on ! ,am]ican side1 ?r\gh ! t[n ( ,niag>a ,falls1 betwe5 ! rapids above & ! v]ge ( ! *asm bel[ ! ,falls1 :]e1 s9ce #ahgd1 a clu/] ( factories has aris51 :i* dis*>ge _! sp5t wat] ov] ! cliff 9 a s]ies ( cascades almo/ rivall+ ,niag>a itself4 ,?is canal1 :i* only taps a m]e drop f ! ocean ( p[] t is runn+ to wa/e1 has be5 utilis$ to ! full2 & ! decrease ( wat]-privileges 9 ! ,new ,engl& ,/ates1 ow+ to ! cle>+ ( ! =e/s & settlem5t ( ! c\ntry1 toge!r ) ! gr[? ( ! electrical indu/ries1 h l$ to a fur!r dem& on ! res\rces ( ,niag>a4 ,) ! example ( ,m9neapolis1 :i* draws ! p[] = its _m mills f ! ,falls ( ,/4 ,an?ony1 9 ! ,mississippi ,riv]1 be=e !m1 a gr\p ( f>-see+ & ent]pris+ citiz5s ( ,niag>a ,falls resolv$ to satisfy ?is requirem5t by ! f\ndation ( an indu/rial city 9 ! neighb\rhood ( ! ,falls4 ,!y p]ceiv$ t a bett] site c\ld n[h]e be f\nd on ! ,am]ican ,cont95t4 ,ap>t f its heal?y air & attractive sc5]y1 ,niag>a is a k9d ( half-way h\se betwe5 ! ,ea/ & ,we/1 ! consum+ & ! produc+ ,/ates4 ,by ! ,erie ,canal at ,tonaw&a x comm&s ! great wat]way ( ! ,lakes & ! ,/4 ,lawr5ce4 ,a sy/em ( trunk railways f diff]5t p>ts ( ! ,/ates & ,canada are focuss$ !re1 & cross ! riv] by ! ,cantilev] & ,susp5sion bridges bel[ ! ,falls4 ,! ,new ,york ,c5tral & ,hudson ,riv]1 ! ,lehigh ,valley1 ! ,buffalo1 ,ro*e/]1 & ,pittsburgh1 ! ,mi*igan ,c5tral1 & ! ,gr& ,trunk ( ,canada1 are "s ( ^! l9es4 ,dra9+ z x does ! great lakes ( ! int]ior1 :i* h a total area ( #ib1jjj squ>e miles1 ) an aggregate bas9 ( #bij1jjj squ>e miles1 ! volume ( wat] 9 ! ,niag>a ,riv] pass+ ov] ! cat>act e second is some?+ l #cjj1jjj cubic feet2 & ?is1 ) a fall ( #bgf feet f ! head ( ! upp] rapids to ! :irlpool rapids bel[1 is equival5t to ab\t n9e million1 or1 all[+ = wa/e 9 ! turb9es1 say1 sev5 million horse- p[]4 ,moreov]1 ! great lakes dis*>g+--into ea* o!r =m a *a9 ( imm5se res]voirs1 & ! level ( ! riv] be+ little affect$ by flood or dr\ght1 ! supply ( pure wat] is practically con/ant all ! ye> r\nd4 ,mr4 ,r4 ,c4 ,reid has %[n t a ra9fall ( ?ree in*es 9 tw5ty-f\r h\rs ov] ! bas9 ( ,lake ,sup]ior w\ld take n9ety days to run (f into ,lake ,huron1 :i*1 ) ,lake ,mi*igan1 w\ld take z long to ov]fl[ into ,lake ,erie2 &1 !re=e1 six mon?s w\ld elapse be=e ! full effect ( ! flood 0 exp5d$ at ! ,falls4 ,! fir/ outcome ( ! movem5t 0 ! ,niag>a ,riv] ,hydraulic ,p[] & ,sew] ,company1 incorporat$ 9 #ahhf1 & succe$$ by ! ,niag>a ,falls ,p[] ,company4 ,! old plan ( utilis+ ! wat] by means ( an op5 canal 0 unsuit$ to ! circum/ances1 & ! company adopt$ t ( ! late ,mr4 ,?omas ,ev]%$1 divisional eng9e] ( ! ,new ,york ,/ate ,canals4 ,l ! o!r1 x consi/s 9 tapp+ ! riv] above ! ,falls1 & us+ ! pressure ( ! wat] to drive ! numb] ( turb9es1 !n re/or+ ! wat] to ! riv] bel[ ! ,falls2 b in/ead ( a surface canal1 ! tail-race is a hydraulic tunnel or und]gr\nd conduit4 ,to ?is end "s fifte5 hundr$ acres ( sp>e l&1 hav+ a frontage j above ! upp] rapids1 0 quietly secur$ at ! l[ price ( ?ree hundr$ doll>s an acre2 & we believe its rise 9 value ow+ to ! progress ( ! works is su* t a ye>ly r5tal ( two hundr$ doll>s an acre c ev5 n[ be got = x4 ,?is l& has be5 laid out z an indu/rial city1 ) a resid5tial qu>t] = ! op]atives1 :>ves along ! riv]1 & sid+s or %ort l9es to connect ) ! trunk railways4 ,9 c>ry+ out _! purpose ! company has budd$ & bran*$ into o!r companies--"o = ! pur*ase ( ! l&2 ano!r = mak+ ! railways2 & a ?ird1 ! ,cat>act ,con/ruction ,company1 :i* is *>g$ ) ! c>ry+ out ( ! eng9e]+ works1 = ! utilisation ( ! wat]-p[]1 & is !re=e ! mo/ important ( all4 ,a subsidi>y company has also be5 =m$ to transmit by electricity a portion ( ! available p[] to ! city ( ,buffalo1 at ! head ( ! ,niag>a ,riv]1 on ,lake ,erie1 "s tw5ty miles di/ant4 ,all ^! affiliat$ bodies are1 h[ev]1 "u ! directorate ( ! ,cat>act ,con/ruction ,company2 & among/ ^? :o h tak5 ! mo/ active "p 9 ! "w we may m5tion ! presid5t1 ,mr4 ,e4 ,d4 ,adams2 ,pr(essor ,coleman ,sell]s1 ! consult+ eng9e]2 & ,pr(essor ,george ,=bes1 ,f4 ,r4 ,s41 ! consult+ electrical eng9e]1 a son ( ! late ,pr9cipal ,=bes ( ,ed9burgh4 ,9 secur+ ! necess>y "r ( way = ! hydraulic tunnel or 9 ! acquisitom ( l&1 ! ,company has %[n consummate tact4 ,a few proprietors decl9$ to accept its t]ms1 & ! ,company select$ a p>allel r\te4 ,hav+ obta9$ ! "r ( way = ! latt]1 x in=m$ ! refractory own]s on ! fir/ l9e ( _! success1 & intimat$ t ! ,company c\ld n[ disp5se ) t4 ,on ?is ! /ickl]s pr(ess$ _! will+ness to accept ! orig9al t]ms1 & ! b>ga9 0 conclud$1 ?us leav+ ! ,company 9 possession ( ! rights ( way = two tunnels1 bo? ( :i* !y propose to utilise4 ,! lib]al policy ( ! directors is des]v+ ( ! highe/ comm5dation4 ,!y h ris5 above m]e *auv9ism1 & in/ead ( n>r[ly conf9+ ! "w to ,am]ican eng9e]s1 !y h avail$ !mselves ( ! be/ sci5tific c\nsel :i* ! entire _w c\ld af=d4 ,! great "q z to ! be/ means ( di/ribut+ & apply+ ! p[] at _! comm& _h to be settl$2 & 9 #ahij1 aft] ,mr4 ,adams & ,dr4 ,sell]s _h made a visit ( inspection to ,europe1 an ,int]national ,commission 0 appo9t$ to consid] ! v>i\s me?ods submitt$ to !m1 & aw>d prizes to ! successful competitors4 ,"l ,kelv9 7!n ,sir ,william ,?omson7 0 ! presid5t1 & ,pr(essor ,w4 ,c4 ,unw91 ! well-kn[n exp]t 9 hydraulic eng9e]+1 ! secret>y1 :ile o!r memb]s 7 ,pr(essor ,masc>t ( ! ,in/itute1 a lead+ ,fr5* electrician2 ,colonel ,turret9i ( ,g5eva1 & ,dr4 ,sell]s4 ,a l>ge numb] ( s*emes 7 s5t 91 & _m di/+ui%$ eng9e]s gave evid5ce be=e ! ,commission4 ,! relative m]its ( compress$ air & electricity z a means ( di/ribut+ ! p[] 7 discuss$1 & on ! :ole ! balance ( op9ion 0 9 fav\r ( electricity4 ,prizes ( two hundr$ & two hundr$ & fifty p\nds 7 aw>d$ to a numb] ( firms :o _h submitt$ plans1 b none ( ^! 7 tak5 up by ! ,company4 ,! impulse turb9es ( ,messrs4 ,faes* ,picc>d1 ( ,g5eva1 :o ga9$ a prize ( two hundr$ & fifty p\nds1 h1 h[ev]1 be5 adopt$ s9ce4 ,x is ano!r pro( ( ! det]m9ation ( ! ,company to procure ! be/ in=mation on ! subject1 reg>dless ( co/1 t ,pr(essor ,=bes _h c>te blan*e to g to any "p ( ! _w & make a report on any sy/em ( electrical di/ribution :i* he might ?9k fit4 ,) ! selection ( electricity ano!r "q arose z to ! exp$i5cy ( employ+ cont9u\s or alt]nat+ curr5ts4 ,at t "t cont9u\s curr5ts 7 *iefly 9 vogue1 & x speaks well = ! sagacity & presci5ce ( ,pr(essor ,=bes t he boldly advocat$ ! adoption ( alt]nat+ curr5ts1 m especially = ! transmission ( p[] to ,buffalo4 ,8 proposals enc\nt]$ /rong opposition1 ev5 9 ! highe/ qu>t]s2 b s9ce !n1 p>tly ow+ to ! /rik+ success ( ! ,lauff5 to ,frank=t exp]im5t 9 transmitt+ p[] by alt]nat+ curr5ts ov] a b>e wire on poles a di/ance ( m ?an a hundr$ miles1 ! directors & eng9e]s h come r\nd to 8 view ( ! matt]1 & alt]nat+ curr5ts h be5 employ$1 at all ev5ts = ! ,buffalo l9e1 & also = ! *ief supply ( ! indu/rial city4 ,cont9u\s curr5ts1 fl[+ always 9 ! same direction1 l ! curr5t ( a batt]y1 c1 x is true1 be /or$ 9 accumulators1 b !y _c be conv]t$ to high] or l[] pressure 9 a trans=m]4 ,alt]nat+ curr5ts1 on ! o!r h&1 :i* see-saw 9 direction _m times a second1 _c be /or$ 9 accumulators1 b !y c be s5t at high pressure along a v f9e wire1 & !n conv]t$ to high] or l[] pressures :]e !y are want$1 & ev5 to cont9u\s curr5ts4 ,ea* k9d1 !re=e1 has its peculi> advantages1 & bo? w be employ$ to "s ext5t4 ,) reg>d to ! eng9e]+ works1 ! hydraulic tunnel />ts f ! bank ( ! riv] :]e x is navigable1 at a po9t a mile & a half above ! ,falls1 & aft] keep+ by ! %ore1 x cuts across ! b5d b5ea? ! city ( ,niag>a ,falls1 & t]m9ates bel[ ! ,susp5sion ,bridge "u ! ,falls at ! level ( ! wat]4 ,x is #fgjj y>ds long1 & ( a horse%oe section1 #ai feet wide by #ba feet high4 ,x has be5 cut #afj feet bel[ ! surface ?r\gh ! lime/one & %ale1 b is ar*$ ) brick1 hav+ rubble above1 & at ! outfall is l9$ on ! inv]t or "u side ) iron4 ,! gradi5t is #cf feet 9 ! mile1 & ! total fall is #bje feet1 ( :i* #adj feet are available = use4 ,! capacity ( ! tunnel is #ajj1jjj horse- p[]4 ,9 ! l&s ( ! company x is #djj feet f ! m>g9 ( ! riv]1 to :i* x is connect$ by a canal1 :i* is ov] #aejj feet long1 #ejj feet wide at ! m\?1 & #ab feet deep4 ,out ( ?is canal1 head-races fitt$ ) sluices conduct ! wat] to a numb] ( :eel-pits #afj feet deep1 :i* h be5 dug ne> ! edge ( ! canal1 & communicate bel[ ) ! tunnel4 ,at ! bottom ( ea* :eel-pit a #ejjj horse-p[] ,gir>d d\ble turb9e is m\nt$ on a v]tical %aft1 :i* drives a propell] %aft ris+ to ! surface ( ! gr\nd2 a dynamo ( #ejjj horse- p[] is fix$ on ! top ( ?is %aft1 & s driv5 by x4 ,! upw>d pressure ( ! wat] is +5i\sly contriv$ to relieve ! f\ndation ( ! weight ( ! turb9e %aft & dynamo4 ,tw5ty ( ^! turb9es1 :i* are made by ! ,i4 ,p4 ,morris ,company ( ,philadelphia1 f ! designs ( ,messrs4 ,faes* & ,picc>d1 w be requir$ to utilize ! full capacity ( ! tunnel4 ,! company possesses a /rip ( l& ext5d+ two miles along ! %ore2 & 9 excavat+ ! tunnel a c(f]-dam 0 made ) ! extract$ rock1 to keep ! riv] f flood+ ! works4 ,?is dam n[ =ms "p ( a sy/em by :i* a tract ( l& has be5 reclaim$ f ! riv]4 ,"p ( x has already be5 acquir$ by ! ,niag>a ,pap] ,pulp ,company1 :i* is build+ gigantic factories1 & w employ ! tailrace or tunnel ( ! ,cat>act ,con/ruction ,company4 ,:>fs = ! use ( %ips & canal boats w also be con/ruct$ on ?is frontage4 ,by l& & wat] ! raw mat]ials ( ! ,we/ w be convey$ to ! indu/rial t[n :i* is n[ com+ into exi/5ce2 gra9 f ! prairies ( ,ill9ois & ,dakota2 timb] f ! =e/s ( ,mi*igan & ,wiscons92 coal & copp] f ! m9es ( ,lake ,sup]ior2 & :at n4 ,x is expect$ t "o indu/ry hav+ a seat !re w attract o!rs4 ,?us1 ! pulp mills w br+ ! mak]s ( pap] :eels & b>rels2 ! smelt+ ( iron w draw f\ndries & eng9e works2 ! electrical ref9+ ( copp] w lead to ! e/abli%m5t ( wire-works1 cable factories1 dynamo %ops1 & s on4 ,alum9um1 too1 promises to create an important indu/ry 9 ! future4 ,9 ! meantime1 ! ,cat>act ,con/ruction ,company is ab\t to />t an electrical factory ( its own1 :i* w give employm5t to a l>ge numb] ( m54 ,x has also und]tak5 ! wat] supply ( ! adjac5t city ( ,niag>a ,falls4 ,! ,cat>act ,electric ,company ( ,buffalo has obta9$ ! exclusive "r to use ! electricity transmitt$ to t city1 & ! l9e w be run 9 a subway4 ,?is und]gr\nd l9e w be m exp5sive to make ?an an ov]head l9e1 b x w n require to be r5ew$ e eight to fifte5 ye>s1 & x w n be liable to int]ruption f ! heavy gales t sweep across ! lakes1 or ! weight ( froz5 sleet3 moreov]1 x w be m easily inspect$1 & q safe = ! public4 ,we %\ld also add t1 9 addition to ! contemplat$ duplicate tunnel ( #ajj1jjj horse-p[]1 ! ,cat>act ,con/ruction ,company owns a concession = utilis+ #bej1jjj horse-p[] f ! ,horse%oe ,falls on ! ,canadian side 9 ! same mann]4 ,x has ?us a virtual monopoly ( ! available wat]-p[] ( ,niag>a1 & ! promot]s h n ! lea/ d\bt t ! ent]prise w be a great f9ancial success4 ,already ! ,pittsburg ,r$uction ,company h begun to use ! electricity 9 r$uc+ alum9um f ! m9]al kn[n z bauxite1 an oxide ( ! metal1 by means ( ! electric furnace4 ,ano!r portion ( ! p[] is to be us$ to produce c>bide ( calcium = ! manufacture ( acetyl5e gas4 ,at a rec5t electrical exhibition held 9 ,new ,york city a model ( ! ,niag>a plant 0 op]at$ by an electric curr5t br\ght f ,niag>a1 #dej miles di/ant2 & a collection ( telephones 7 s connect$ t ! spectator c\ld he> ! ro> ( ! real cat>act4 ,?anks to ! =esight ( ,new ,york ,/ate & ,canada1 ! sc5]y ( ! ,falls has be5 pres]v$ by ! in/itution ( public p>ks1 & ! works 9 "q w d no?+ to spoil x1 especially z !y w be free f smoke4 ,mr4 ,bog>ts1 ,/ate ,eng9e] ( ,new ,york1 e/imates t ! wat] drawn f ! riv] w only l[] ! mean dep? ( ! ,falls ab\t two in*es1 & w !re=e make no appreciable diff]5ce 9 ! view4 ,altoge!r1 ! ent]prise is some?+ new 9 ! hi/ory ( ! _w4 ,x is n only ! gr&e/ application ( electrical p[]1 b "o ( ! mo/ rem>kable feats 9 an age :5 romance has become sci5ce1 & sci5ce has become romance4 ,,*apt] ,,ix4 ,,m9or ,,uses ,,( ,,electricity4 ,! electric trembl+ bell1 n[ 9 common use1 0 fir/ inv5t$ by ,john ,mir& 9 #ahej4 ,figure #hc %[s ! s*eme ( ! circuit1 :]e ,b is a small batt]y1 say two or ?ree dry or ,leclan*e cells1 jo9$ by insulat$ wire to ,p1 a press-button or contact key1 & ,g an electromagnetic gong or bell4 ,on press+ ! button ,p1 a spr+ contact is made1 & ! curr5t fl[+ ?r\gh ! circuit /rikes ! bell4 ,! action ( ! contact key w be und]/ood f figure #hd1 :]e ,p is ! press-button remov$ to %[ ! und]ly+ me*anism1 :i* is m]ely a metal spr+ ,a ov] a metal plate ,b4 ,! spr+ is connect$ by wire to a pole ( ! batt]y1 & ! plate to a t]m9al or b9d+ screw ( ! bell1 or vice v]sa4 ,:5 ! button ,p is press$ by ! f+] ! spr+ is =c$ aga9/ ! plate1 ! circuit is made1 & ! bell r+s4 ,on releas+ ! button x spr+s back1 ! circuit is brok51 & ! bell /ops4 ,figure #he %[s ! inn] me*anism ( ! bell1 :i* consi/s ( a d\ble-pol$ electromagnet ,m1 hav+ a s(t iron armature ,a h+$ on a /raight spr+ or tongue ,s1 ) "o end fix$1 & ! o!r re/+ aga9/ a screw contact ,t4 ,! hamm] ,h projects f ! armature beside ! edge ( ! gong ,e4 ,9 pass+ ?r\gh ! in/rum5t ! curr5t proce$s f "o t]m9al1 say t on ! "r1 by ! wire ,w to ! screw contact ,t1 & !nce by ! spr+ ,s ?r\gh ! bobb9s ( ! electromagnet to ! o!r t]m9al4 ,! electromagnet attracts ! armature ,a1 & ! hamm] ,h /rikes ! gong2 b 9 ! act ! spr+ ,s is drawn f ! contact ,t1 & ! circuit is brok54 ,consequ5tly ! electromagnet1 no long] excit$1 lets ! armature g1 & ! spr+ leaps back aga9/ ! contact ,t1 )draw+ ! hamm] f ! gong4 ,b ! in/rum5t is n[ z x 0 at fir/1 ! curr5t aga9 fl[s1 & ! hamm] /rikes ! gong1 only to fly back a second "t4 ,9 ?is way1 z long z ! button is press$ by ! op]ator1 ! hamm] w cont9ue to tap ! bell & give a r++ s\nd4 ,press-buttons are ( v>i\s patt]ns1 & ei!r affix$ to ! wall or ins]t$ 9 ! h&le ( an ord9>y bell-pull1 z %[n 9 figure #hf4 ,! ord9>y electric bell actuat$ by a batt]y is liable to get out ( ord] ow+ to ! batt]y sp5d+ its =ce1 or to ! contacts becom+ dirty4 ,magnetoelectric bells h1 !re=e1 be5 introduc$ ( late ye>s4 ,) ^! no batt]y or int]rupt+ contacts are requir$1 s9ce ! bell-pull or press- button is made 9 ! =m ( a small dynamo :i* g5]ates ! curr5t :5 x is pull$ or pu%$4 ,figure #hg illu/rates a =m ( ?is app>atus1 :]e ,m ,p is ! bell-pull & ,b ! bell1 ^! be+ connect$ by a d\ble wire ,w1 to convey ! curr5t4 ,! bell-pull consi/s ( a horse%oe magnet ,m1 hav+ a bobb9 ( insulat$ wire betwe5 its poles1 & m\nt$ on a sp9dle4 ,:5 ! key ,p is turn$ r\nd by ! h&1 ! bobb9 moves 9 ! magnetic field betwe5 ! poles ( ! magnet1 & ! curr5t ?us g5]at$ circulates 9 ! wires ,w1 & pass+ ?r\gh an electromagnet "u ! bell1 attracts its armature1 & /rikes ! hamm] on ! bell4 ,( c\rse ! bell may be plac$ at any di/ance f ! g5]ator4 ,9 o!r types ! curr5t is g5]at$ & ! bell rung by ! act ( pull+1 z 9 a common h\se-bell4 ,electric bells 9 l>ge h\ses & hotels are usually fitt$ up ) indicators1 z %[n 9 figure #hh1 :i* tell ! room f :i* ! call proce$s4 ,!y are s]viceable z in/antane\s signals1 annunciators1 & al>ms 9 _m diff]5t ways4 ,an outbreak ( fire c be ann\nc$ by caus+ ! undue rise ( temp]ature to melt a piece ( tall[ or fusible metal1 & ?us release a weight1 :i* tails on a press-button1 & closes ! circuit ( an electric bell4 ,or1 ! ris+ temp]ature may exp& ! m]cury 9 a tube l t ( a !rmomet] until x connects two plat9um wires fus$ ?r\gh ! glass & 9 circuit ) a bell4 ,"s employ a curv+ bi-metallic spr+ to make ! necess>y contact4 ,! spr+ is made by sold]+ /rips ( brass & iron back to back1 & z ^! metals exp& unequally :5 heat$1 ! spr+ is de=m$1 & t\*es ! contact :i* is connect$ 9 ! circuit1 ?us p]mitt+ ! curr5t to r+ ! bell4 ,a /ill bett] device1 h[ev]1 is a small box conta9+ a ?9 metallic diaphragm1 :i* exp&s ) ! heat1 & sagg+ 9 ! c5tre1 t\*es a contact screw1 ?us complet+ ! circuit1 & all[+ ! curr5t to pass4 ,^! automatic or self-act+ fire-al>ms c1 ( c\rse1 be connect$ 9 ! circuit ( ! ord9>y /reet fire-al>ms1 :i* are usually work$ by pull+ a h&le to make ! necess>y contact4 ,f :at has be5 said1 x w be easy to und]/& h[ ! /eal?y entrance ( burgl>s into a h\se c be ann\nc$ by an electric bell or w>n+ lamp4 ,if press-buttons or contact-keys are plac$ on ! sa%es ( ! w9d[s1 ! po/s ( ! door1 or ! treads ( ! /air1 s t :5 ! w9d[ or door is op5$1 or ! tread b5ds "u ! foot/ep1 an electric circuit is clos$1 ! al>m w be giv54 ,( c\rse1 ! connections ne$ only be arrang$ :5 ! device is want$4 ,%ops & (fices c be gu>d$ by mak+ ! curr5t %[ a r$ light f a lamp hung 9 front ( ! premises1 s t ! night wat*man c see x on 8 beat4 ,?is c readily be done by adju/+ an electromagnet to drop a scre5 ( r$ glass be=e ! flame ( ! lamp4 ,safes & %[cases =cibly op5$ c be made to signal ! fact1 & rec5tly 9 ! ,unit$ ,/ates a ?ief 0 photograph$ by a fla%light k9dl$ 9 ?is way1 & aft]w>ds captur$ ?r\gh ! lik5ess4 ,! level ( wat] 9 ci/]ns & res]voirs1 c be told 9 a simil> mann] by caus+ a float to rise ) ! wat] & make ! requir$ contact4 ,! degree ( fro/ 9 a cons]vatory c also be ann\nc$ by means ( ! m]cury !rmo/at1 already describ$1 or "s equival5t device4 ,!re are1 inde$1 _m actual or possible applications ( a simil> k9d4 ,! ,massey log is an in/rum5t = tell+ ! spe$ ( a %ip by ! revolutions ( a fly z x is t[$ ?r\gh ! wat]1 & by mak+ ! fly complete a circuit z x revolves ! numb] ( turns a second c be /ruck by a bell on bo>d4 ,9 "o =m ( ! electric log1 ! curr5t is g5]at$ by ! *emical action ( z9c & copp] plates atta*$ to ! log1 & imm]s$ 9 ! sea wat]1 & 9 o!rs provid$ by a batt]y on ! %ip4 ,capta9 ,m',evoy has inv5t$ an al>m = torp$oes & torp$o boats1 :i* is a v]itable wat*dog ( ! sea4 ,x consi/s ( an iron bell-j> inv]t$ 9 ! wat]1 & moor$ at a dep? bel[ ! agitation ( ! waves4 ,9 ! upp] "p ( ! j>1 :]e ! pressure ( ! air keeps back ! wat]1 !re is a delicate ne$le contact 9 circuit ) a batt]y & an electric bell or lamp1 z ! case may be1 on ! %ore4 ,waves ( s\nd pass+ ?r\gh ! wat] f ! screw propell] ( ! torp$o1 or1 inde$1 any %ip1 make & break ! s5sitive contact1 & r+ ! bell or light ! lamp4 ,! app>atus is int5d$ to al>m a fleet ly+ at an*or or a port 9 "t ( w>4 ,electricity has also be5 employ$ to regi/] ! movem5ts ( wea!rcocks & anemomet]s4 ,a few ye>s ago x 0 appli$ successfully to telegraph ! c\rse m>k$ by a /e]+ compass to ! navigat+ (fic] on ! bridge4 ,?is 0 done )\t imp$+ ! motion ( ! compass c>d by caus+ an electric sp>k to jump f a light po9t] on ! c>d to a s]ies ( metal plates r\nd ! b[l ( ! compass1 & actuate an electric al>m4 ,! ,dome/ic ,telegraph1 an ,am]ican device1 is a little dial app>atus by :i* a citiz5 c signal = a policeman1 doctor1 mess5g]1 or c>riage1 z well z a fire eng9e1 by ! simple act ( sett+ a h& on ! dial4 ,alex&] ,ba9 0 ! fir/ to drive a clock ) electricity in/ead ( weights1 by employ+ a p5dulum hav+ an iron bob1 :i* 0 attract$ to "o side & ! o!r by an electromagnet1 b z its rate dep5ds on ! con/ancy ( ! curr5t1 :i* is n easy to ma9ta91 ! inv5tion has n come into g5]al use4 ,! butt]fly clock ( ,lemo9e1 :i* we illu/rate 9 figure #hi1 is an improv$ type1 9 :i* ! bob ( s(t iron ,p sw+s to & fro ov] ! poles ( a d\ble electro magnet ,m 9 circuit ) a batt]y & contact key4 ,:5 ! rate is too sl[ ! key is clos$1 & a curr5t pass+ ?r\gh ! electromagnet pulls on ! p5dulum1 ?us correct+ ! clock4 ,?is is done by ! +5i\s device ( ,hipp1 %[n 9 figure #ij1 :]e ,m is ! electromagnet1 ,p ! iron bob1 f :i* projects a wire be>+ a light vane ,b ( mica 9 ! %ape ( a butt]fly4 ,z ! bob sw+s ! wire drags ov] ! hump ( ! metal spr+ ,s1 & :5 ! bob is go+ too sl[ly ! wire ?ru/s ! spr+ into contact ) ano!r spr+ ,t bel[1 ?us clos+ ! circuit1 & s5d+ a curr5t ?r\gh ! magnet ,m1 :i* attracts ! bob & gives a fillip to ! p5dulum4 ,local clocks controll$ f a /&>d clock by electricity h be5 m successful 9 practice1 & are employ$ 9 sev]al t[ns--= example1 ,glasg[4 ,beh9d local dials are electromagnets :i*1 by means ( an armature work+ a frame & rat*et :eel1 move ! h&s =w>d e m9ute or half-m9ute z ! curr5t is s5t f ! /&>d clock4 ,! electrical *ronograph is an in/rum5t = measur+ m9ute int]vals ( "t by means ( a /ylus trac+ a l9e on a b& ( travell+ pap] or a revolv+ b>rel ( smok$ glass4 ,! curr5t1 by excit+ an electromagnet1 j]ks ! /ylus1 & ! int]val betwe5 two j]ks is f\nd f ! l5g? ( ! trace betwe5 !m & ! spe$ ( ! pap] or smok$ surface4 ,ret>d$ clocks are sometimes employ$ z electric met]s = regi/]+ ! consumption ( electricity4 ,9 ^! ! curr5t to be measur$ fl[s ?r\gh a coil b5ea? ! bob ( ! p5dulum1 :i* is a magnet1 & ?us affects ! rate4 ,9 o!r met]s ! curr5t passes ?r\gh a species ( galvanomet] call$ an amp]e met]1 & controls a clockwork c\nt]4 ,9 a ?ird k9d ( met] ! *emical effect ( ! curr5t is br\ght into play-- t ( ,edison1 = example1 decompos+ sulphate ( copp]1 or m commonly ( z9c4 ,! electric light is n[ us$ = signall+ & adv]tis+ by night 9 a v>iety ( ways4 ,inc&esc5t lamps inside a transluc5t balloon1 & _! light controll$ by a curr5t key1 z 9 a telegraph circuit1 s z to give long & %ort fla%es1 accord+ to ! ,morse code1 are employ$ 9 ! army4 ,signals at sea are also made by a set ( r$ & :ite gl[-lamps1 :i* are comb9$ accord+ to ! code 9 use4 ,! p[]ful arc lamp is extremely useful z a se>* light1 especially on m5 ( w> & =tifications1 & x has also be5 tri$ 9 signall+ by project+ ! beam on ! cl\ds by way ( a scre51 & eclips+ x accord+ to a giv5 code4 ,9 #ahgi1 ,pr(essor ,graham ,bell1 ! inv5tor ( ! speak+ telephone1 & ,mr ,summ] ,tamt]1 br\ght out an +5i\s app>atus call$ ! photophone1 by :i* music & spee* 7 s5t along a beam ( light = sev]al hundr$ y>ds4 ,! action ( ! photophone is bas$ on ! peculi> fact obs]v$ 9 #ahgc by ,mr ,j ,e ,mayhew1 t ! electrical resi/ance ( cry/all9e sel5ium dim9i%es :5 a ray ( light falls ^u x4 ,figure #ia %[s h[ ,bell & ,tamt] utilis$ ?is prop]ty 9 ! telephone4 ,a beam ( sun or electric light1 conc5trat$ by a l5s ,l1 is reflect$ by a ?9 mirror ,m1 & aft] trav]s+ ano!r l5s ,l1 travels to ! p>abolic reflector ,r1 9 ! focus ( :i* !re is a sel5ium resi/ance 9 circuit ) a batt]y ,s & two telephones ,t ,t'4 ,n[1 :5 a p]son speaks into ! tube at ! back ( ! mirror ,m1 ! light is caus$ to vibrate ) ! s\nds1 & a wav]+ beam falls on ! sel5ium1 *ang+ its resi/ance to ! curr5t4 ,! /r5g? ( ! curr5t is ?us v>i$ ) ! sonor\s waves1 & ! words spok5 by ! transmitt] are he>d 9 ! telephones by ! receiv]4 ,! photophone is1 h[ev]1 m ( a sci5tific toy ?an a practical in/rum5t4 ,becqu]el1 ! ,fr5* *emi/1 f\nd t two plates ( silv] fre%ly coat$ ) silv] f a solution ( *loride ( silv] & plung$ into wat]1 =m a voltaic cell :i* is s5sitive to light4 ,?is c be se5 by connect+ ! plates ?r\gh a galvanomet]1 & all[+ a ray ( light to fall ^u !m4 ,o!r comb9ations ( ! k9d h be5 discov]$1 & ,pr(essor ,m9*91 ! ,iri% physici/1 has us$ "o ( ^! cells to measure ! int5sity ( />light4 ,! induction balance ( ,pr(essor ,hughes is f\nd$ on ! well-kn[n fact t a curr5t pass+ 9 "o wire c induce a sympa!tic curr5t 9 a neighb\r+ wire4 ,! arrangem5t w be und]/ood f figure #ib1 :]e ,p & ,p#a are two simil> coils or bobb9s ( ?ick wire 9 circuit ) a batt]y ,b & a microphone ,m1 :ile ,s & ,s#a are two simil> coils or bobb9s ( f9e wire 9 circuit ) a telephone ,t4 ,x ne$ h>dly be said t :5 ! microphone ,m is di/urb$ by a s\nd1 ! curr5t 9 ! prim>y coils ,p ,p#a w induce a correspond+ curr5t 9 ! second>y coils ,s ,s#a2 b ! coils ,s ,s#a are s w\nd t ! induction ( ,p on ,s neutralises ! induction ( ,p#a on ,s#a2 & no curr5t passes 9 ! second>y circuit1 h5ce no s\nd is he>d 9 ! telephone4 ,:51 h[ev]1 ?is balance ( induction is upset by br++ a piece ( metal--say1 a co9--ne> "o or o!r ( ! coils ,s ,s#a1 a s\nd w be he>d 9 ! telephone4 ,! induction balance has be5 us$ z a ,sonomet] = measur+ ! s5se ( he>+1 & also = tell+ base co9s4 ,! writ] devis$ a =m ( x = div9+ ! pres5ce ( gold & metallic ores :i* has be5 appli$ by ,capta9 ,m',evoy 9 8 subm>9e detector = explor+ ! sea bottom = lo/ an*ors & sunk5 treasure4 ,:5 ,presid5t ,g>field 0 %ot1 ! position ( ! bullet 0 asc]ta9$ by a simil> arrangem5t4 ,! microphone z a means ( magnify+ feeble s\nds has be5 employ$ = localis+ ! leaks 9 wat] pipes & 9 m$ical exam9ations4 ,"s ye>s ago x sav$ a ,russian lady f premature burial by r5d]+ ! fa9t beat+ ( h] he>t audible4 ,edison's electric p5 is useful 9 copy+ lett]s4 ,x works by punctur+ a r[ ( m9ute holes along ! l9es ( ! writ+1 & ?us produc+ a /5cil plate1 :i*1 :5 plac$ ov] a clean %eet ( pap] & bru%$ ) ink1 gives a duplicate ( ! writ+ by ! ink p5etrat+ ! holes to ! pap] bel[4 ,x is illu/rat$ 9 figure #ic1 :]e ,p is ! p51 consi/+ ( a holl[ /em 9 :i* a f9e ne$le actuat$ by ! armature ( a small electromagnet plies rapidly up & d[n & pi]ces ! pap]4 ,! curr5t is d]iv$ f a small batt]y ,b1 & an ink+ roll] l t us$ 9 pr9t+ s]ves to apply ! ink4 ,9 #ahgh ,mr4 ,edison ann\nc$ 8 inv5tion ( a ma*9e = ! /orage & reproduction ( spee*1 & ! ann\ncem5t 0 receiv$ ) a good deal ( incr$ulity1 not)/&+ ! p>tial success ( ,fab] & o!rs 9 devis+ me*anical articulators4 ,! simplicity ( ,edison's inv5tion :5 x 0 se5 & he>d elicit$ mu* admiration1 & al?\gh 8 fir/ in/rum5t 0 obvi\sly imp]fect1 x 0 nev]!less reg>d$ z ! g]m ( some?+ bett]4 ,if ! words spok5 into ! in/rum5t 7 he>d 9 ! fir/ place1 ! lik5ess ( ! reproduction 0 f\nd to be unmi/akable4 ,inde$1 s fai?ful 0 ! replica1 t a memb] ( ! ,academy ( ,sci5ces1 ,p>is1 /\tly ma9ta9$ t x 0 due to v5triloquism or "s o!r trick]y4 ,x 0 evid5t1 h[ev]1 t be=e ! phonograph c\ld become a practical in/rum5t1 fur!r improvem5ts 9 ! nicety ( its articulation 7 requir$4 ,! introduction ( ! electric light div]t$ ,mr4 ,edison f ! task ( improv+ x1 al?\gh he does n seem to h lo/ fai? 9 8 pet inv5tion4 ,dur+ ! next t5 ye>s he accumulat$ a l>ge =tune1 & 0 ! pr9cipal means ( introduc+ bo? electric light & p[] to ! _w at l>ge4 ,?is done1 h[ev]1 he return$ to 8 e>li] love1 & has at l5g? succe$$ 9 p]fect+ x s z to r$eem 8 pa/ promises & fulfill 8 hopes reg>d+ x4 ,! old in/rum5t consi/$1 z is well kn[n1 ( a vibrat+ tympan or drum1 f ! c5tre ( :i* project$ a /eel po9t or /ylus1 9 su* a mann] t on speak+ to ! tympan its vibrations w\ld urge ! /ylus to dig into a %eet ( t9foil mov+ pa/ its po9t4 ,! foil 0 support$ on a groov$ b>rel1 s t ! holl[ ( ! groove beh9d x p]mitt$ ! foil to give "u ! po9t ( ! /ylus1 & take a corrugat$ or wavy surface correspond+ to ! vibrations ( ! spee*4 ,?us record$ on a yield+ b some:at /iff mat]ial1 ^! undulations c\ld be pres]v$1 & at a future "t made to deflect ! po9t ( a simil> /ylus1 & set a correspond+ diaphragm or tympan into vibration1 s z to give out ! orig9al s\nds1 or an imitation ( !m4 ,t9foil1 h[ev]1 is n a v satisfactory mat]ial on :i* to receive ! vibrations 9 ! fir/ place4 ,x does n precisely respond to ! movem5ts ( ! m>k+ /ylus 9 tak+ ! impression1 & does n guide ! receiv+ /ylus suffici5tly well 9 reproduc+ s\nds4 ,mr4 ,edison has !re=e adopt$ wax 9 pref]5ce to x2 & in/ead ( t9foil spread on a groov$ support1 he n[ employs a cyl9d] ( wax to take ! pr9t ( ! vibrations4 ,moreov]1 he no long] uses ! same k9d ( diaphragm to pr9t & receive ! s\nds1 b employs a m delicate "o = receiv+ !m4 ,! m>k+ cyl9d] is n[ kept 9 motion by an electric motor1 in/ead ( by h&-turn+1 z 9 ! e>li] in/rum5t4 ,! new phonograph1 :i* we illu/rate 9 figure #id1 is ab\t ! size ( an ord9>y sew+ ma*9e1 & is ( exquisite workman%ip1 ! p]=mance dep5d+ to a great ext5t on ! p]fection & fitness ( ! me*anism4 ,x consi/s ( a horizontal sp9dle ,s1 c>ry+ at "o end ! wax cyl9d] ,c1 on :i* ! sonor\s vibrations are to be impr9t$4 ,ov] ! cyl9d] is support$ a diaphragm or tympan ,t1 provid$ ) a conical m\?piece ,m = speak+ into4 ,"u ! tympan !re is a delicate ne$le or /ylus1 ) its po9t project+ f ! c5tre ( ! tympan d[nw>ds to ! surface ( ! wax cyl9d]1 s t :5 a p]son speaks into ! m\?piece1 ! voice vibrates ! tympan & drives ! po9t ( ! /ylus d[n into ! wax1 mak+ an impr9t m or less deep 9 accordance ) ! vibrations ( ! voice4 ,! cyl9d] is kept revolv+ 9 a spiral pa?1 at a uni=m spe$1 by means ( an electric motor ,e1 fitt$ ) a s5sitive regulator & situat$ at ! base ( ! ma*9e4 ,! result is t a delicate & ridgy trace is cut 9 ! surface ( wax along a spiral l9e4 ,?is is ! s\nd record1 & by sub/itut+ a f9] tympan = ! "o us$ 9 produc+ x1 ! ridges & inequalities ( ! trace c be made to agitate a light /ylus re/+ on !m1 & cause x to set ! delicate tympan into vibrations correspond+ v accurately to ^? ( ! orig9al s\nds4 ,! tympan employ$ = receiv+ is made ( gold-beat]'s sk91 hav+ a /ud at its c5tre & a spr+y /ylus ( /eel wire4 ,! s\nds emitt$ by ?is device are almo/ a :isp] z comp>$ to ! orig9al ones1 b !y are fai?ful 9 articulation1 :i* is ! ma9 object1 & !y are convey$ to ! e> by means ( flexible he>+-tubes4 ,^! tympans are int]*angeable at w1 & ! arm :i* c>ries !m is also provid$ ) a turn+ tool = smoo?+ ! wax cyl9d] prior to its receiv+ ! pr9t4 ,! cyl9d]s are made ( diff]5t sizes1 f #a to #h in*es long & #d in*es 9 diamet]4 ,! =m] has a /orage capacity ( #bjj words4 ,! next 9 size has twice t1 or #djj words1 & s on4 ,mr4 ,edison /ates t f\r ( ! l>ge #h-;in* cyl9d]s c record all ,ni*olas ,nickleby1 :i* c\ld !re=e be automatically read to a private invalid or to a numb] ( pati5ts 9 a hospital simultane\sly1 by means ( a bun* ( he>+-tubes4 ,! cyl9d]s c be readily po/$ l lett]s1 & made to deliv] _! cont5ts viva voce 9 a duplicate phonograph1 e tone & expression ( ! writ] be+ r5d]$ ) m or less fidelity4 ,! phonograph has prov$ s]viceable 9 record+ ! languages & dialects ( vani%+ races1 z well z 9 tea*+ pronunciation4 ,! dim5sions1 =m1 & consequ5t appe>ance ( ! pres5t comm]cial ,am]ican phonograph are q diff]5t f t above describ$1 b ! und]ly+ pr9ciples & op]ations are id5tical4 ,a device = light+ gas by ! electric sp>k is %[n 9 figure #ie1 :]e ,a is a flat vulcanite box1 conta9+ ! app>atus :i* g5]ates ! electricity1 & a /em or po9t] ,l1 :i* applies ! sp>k to ! gas jet4 ,! g5]ator consi/s ( a small influ5ce ma*9e1 :i* is />t$ by press+ ! ?umb- key ,c on ! side ( ! box4 ,! rotation ( a disc inside ! box produces a supply ( /atic electricity1 :i* passes 9 a /ream ( sp>ks betwe5 two contact-po9ts 9 ! op5 end ( ! /em ,d4 ,! latt] is tubul>1 & conta9s a wire insulat$ f ! metal ( ! tube1 & =m+ ) ! tube ! circuit = ! electric dis*>ge4 ,! h&le enables ! contrivance to be readily appli$4 ,! app>atus is "o ( ! few successful practical applications ( /atic electricity4 ,o!r electric gas-light]s consi/ ( metal po9ts plac$ on ! burn]1 s t ! electric sp>k f a small induction coil or dynamo k9dles ! jet4 ,a plat9um wire made :ite-hot by ! passage ( a curr5t is sometimes us$ to light lamps1 z %[n 9 figure #if1 :]e ,w is a small spiral ( plat9um connect$ 9 circuit ) a g5]ator by ! t]m9als ,t ,t4 ,:5 ! lamp ,l is press$ aga9/ ! button ,b ! wire gl[s & lights x4 ,explosives1 su* z gunp[d] & guncotton1 are also ignit$ by ! electric sp>k f an induction coil or ! inc&esc5ce ( a wire4 ,figure #ig %[s ! int]ior ( an ord9>y electric fuse = bla/+ or explod+ und]gr\nd m9es4 ,x consi/s ( a box ( wood or metal prim$ ) gunp[d] or o!r explosive1 & a plat9um wire ,p sold]$ to a pair ( /\t copp] wires ,w1 insulat$ ) gutta-p]*a4 ,:5 ! curr5t is s5t along ^! wires1 ! plat9um gl[s & ignites ! explosive4 ,detonat+ fuses are prim$ ) fulm9ate ( m]cury4 ,spr+s = wat*es & o!r purposes are temp]$ by heat+ !m ) ! curr5t & qu5*+ !m 9 a ba? ( oil4 ,electrical caut]y is p]=m$ ) an inc&esc5t plat9um wire 9 lieu ( ! knife1 especially = su* op]ations z ! removal ( ! tongue or a tum\r4 ,x 0 kn[n to ! anci5ts t a fi% call$ a torp$o exi/$ 9 ! ,m$it]ranean :i* 0 capable ( adm9i/]+ a %ock to p]sons & b5umb+ !m4 ,! torp$o1 or electric ray1 is f\nd 9 ! ,atlantic z well z ! ,m$it]ranean1 & is alli$ to ! skate4 ,x has an electric organ compos$ ( #hjj or #ajjj polygonal cells 9 its head1 & ! dis*>ge1 :i* appe>s to be a vibratory curr5t1 passes f ! back or positive pole to ! belly or negative pole ?r\gh ! wat]4 ,! gymotus1 or ,sur9am eel1 :i* atta9s a l5g? ( five or six feet1 has an electric organ f head to tail1 & c give a %ock suffici5t to kill a man4 ,humboldt has left a vivid picture ( ! frantic /ruggles ( wild horses driv5 by ! ,indians ( ,v5ezuela into ! ponds ( ! savannahs infe/$ by ^! eels1 9 ord] to make !m dis*>ge _! ?und]bolts & be readily caught4 ,o!r fi%es--! silurus1 malapt]urus1 & s on--are likewise end[$ ) electric batt]ies = /unn+ & captur+ _! prey4 ,! action ( ! organs is /ill a my/]y1 z1 inde$1 is ! :ole subject ( animal electricity4 ,nobili & ,matteucci discov]$ t feeble curr5ts are g5]at$ by ! excitation ( ! n]ves & ! contraction ( ! muscles 9 ! human subject4 ,electricity promises to become a valuable rem$y1 & curr5ts-- cont9u\s1 int]mitt5t1 or alt]nat+--are appli$ to ! body 9 n]v\s & muscul> affections ) good effect2 b ?is %\ld only be done "u m$ical advice1 & ) prop] app>atus4 ,9 _m cases ( sev]e electric %ock or lightn+ /roke1 dea? is m]ely app>5t1 & ! p]son may be br\ght back to life by ! me?od ( artificial respiration & rhy?mic traction ( ! tongue1 z appli$ to ! victims ( dr[n+ or dead fa9t4 ,a good lightn+ conductor %\ld n h a high] electrical resi/ance ?an #aj ohms f ! po9t to ! gr\nd1 includ+ ! e>? contact4 ,exceptionally good conductors h only ab\t #e ohms4 ,a high resi/ance 9 ! rod is due ei!r to a flaw 9 ! conductor or a bad e>? connection1 & 9 su* a case ! rod may be a s\rce ( dang] in/ead ( security1 s9ce ! dis*>ge is apt to f9d its way ?r\gh "s "p ( ! build+ to ! gr\nd1 r ?an entirely by ! rod4 ,x is1 !re=e1 important to te/ lightn+ conductors f "t to "t1 & ! magneto-electric te/] ( ,siem5s1 :i* we illu/rate 9 figures #ih & #ii1 is v s]viceable = ! purpose1 & requires no batt]y4 ,! app>atus consi/s ( a magneto-electric ma*9e ,,at1 :i* g5]ates ! te/+ curr5t by turn+ a h&le1 & a ,:eat/one bridge4 ,! latt] comprises a r+ ( ,g]man silv] wire1 =m+ two bran*es4 ,a contact lev] ,p moves ov] ! r+1 & is us$ z a batt]y key4 ,a small galvanomet] ,g %[s ! indications ( ! te/+ curr5t4 ,a brass slid+ piece ,s puts ! galvanomet] ne$le 9 & out ( action4 ,!re are also sev]al connect+ t]m9als1 b b'1 l1 c41 & a comp>ison resi/ance ,r 7figure #ih74 ,a small key ,k is fix$ to ! t]m9al l 7figure #ii71 & us$ to put ! curr5t on ! lightn+-rod1 or take x (f at w4 ,a lea!r bag ,a at "o side ( ! wood5 case 7figure #ii7 holds a d\ble conductor lead+ wire1 :i* is us$ = connect+ ! magneto-electric ma*9e to ! bridge4 ,on turn+ ! h&le ( ,m ! curr5t is g5]at$1 & on clos+ ! key ,k x circulates f ! t]m9als ( ! ma*9e ?r\gh ! bridge & ! lightn+-rod jo9$ ) ! latt]4 ,! ne$le ( ! galvanomet] is deflect$ by x1 until ! resi/ance 9 ! box ,r is adju/$ to balance t 9 ! rod4 ,:5 ?is is s1 ! galvanomet] ne$le rema9s at re/4 ,9 ?is way ! resi/ance ( ! rod is told1 & any *ange 9 x not$4 ,9 ord] to effect ! te/1 x is necess>y to h two e>? plates1 ,e#a & ,e#b1 "o 7,el7 t ( ! rod1 & ! o!r 7,e#b7 t = connect+ to ! te/+ app>atus by ! t]m9al b#a 7figure #ii74 ,! :ole in/rum5t only weighs ab\t #i lbs4 ,9 ord] to te/ ! e>? alone1 a copp] wire %\ld be sold]$ to ! rod at a conv5i5t height above ! gr\nd1 & t]m9al screws fitt$ to x1 z %[n at ,t 7figure #ii71 s t in/ead ( jo9+ ! :ole rod 9 circuit ) ! app>atus1 only t "p f ,t d[nw>ds is connect$4 ,! ,hon4 ,r4 ,ab]crombie has rec5tly drawn att5tion to ! fact t !re are ?ree types ( ?und]/orm 9 ,great ,brita94 ,! fir/1 or squall ?und]/orms1 are squalls associat$ ) ?und] & lightn+4 ,!y =m on ! sides ( prim>y cyclones4 ,! second1 or commone/ ?und]/orms1 are associat$ ) second>y cyclones1 & are r>ely accompani$ by squalls ,! ?ird1 or l9e ?und]/orms1 take ! =m ( n>r[ b&s ( ra9 & ?und]--= example1 #ajj miles long by #e to #aj miles broad4 ,!y cross ! c\ntry rapidly1 & ne>ly broadside on4 ,^! are usually prec$$ by a viol5t squall1 l t :i* capsiz$ ! ,eurydice4 ,! gloom ( ,janu>y1 #ahif1 ) its w> & rum\rs ( w>1 01 at all ev5ts1 reliev$ by a s+le bright spot4 ,electricity has surpris$ ! _w ) a new m>vel1 :i* confirms h] title to be reg>d$ z ! mo/ miracul\s ( all ! sci5ces4 ,)9 ! pa/ tw5ty ye>s %e has giv5 u ! telephone ( ,bell1 enabl+ ,london to speak ) ,p>is1 & ,*icago ) ,new ,york2 ! microphone ( ,hughes1 :i* makes ! tread ( a fly s\nd l ! tramp ( an elephant1 z ,"l ,kelv9 has said2 ! phonograph ( ,edison1 9 :i* we c he> aga9 ! voices ( ! dead2 ! electric light :i* gl[s )\t air & und]wat]1 electric heat )\t fire1 electric p[] )\t fuel1 & a great deal m beside4 ,to ^! triumphs we mu/ n[ add a means ( photograph+ unse5 objects1 su* z ! bony skeletons 9 ! liv+ body1 & s reveal+ ! invisible4 ,:e!r x be t ! press & g5]al public are gr[+ m enlight5$ 9 matt]s ( sci5ce1 or t ,pr(essor ,rontg5's discov]y appeals 9 a peculi> way to ! popul> imag9ation1 x has c]ta9ly evok$ a liveli] & m sudd5 int]e/ ?an ei!r ! telephone1 microphone1 or phonograph4 ,i 0 pres5t :5 ,"l ,kelv9 fir/ ann\nc$ ! inv5tion ( ! telephone to a ,briti% audi5ce1 & %[$ ! in/rum5t itself1 b ! intellig5ce 0 receiv$ s apa!tically t ,i suspect its importance 0 h>dly realis$4 ,x fell to my own lot1 a few ye>s aft]w>ds1 to publi% ! fir/ acc\nt ( ! phonograph 9 ?is c\ntry1 & ,i rememb] t1 betwe5 incr$ulity on ! "o h&1 & p]haps lack ( sci5tific int]e/ on ! o!r1 a consid]able "t elaps$ be=e ! public at l>ge 7 really impress$ by ! inv5tion4 ,p]haps ! uncanny & my/]i\s results ( ,rontg5's discov]y1 :i* seem to l9k x ) ! black arts1 h some?+ to d ) ! quickness ( its reception by all mann] ( p4 ,l mo/1 if n all1 discov]ies & inv5tions1 x is ! outcome ( "w already done by o!r m54 ,9 ! e>ly days ( electricity x 0 f\nd t :5 an electric sp>k f a frictional ma*9e 0 s5t ?r\gh a glass bulb f :i* ! air _h be5 suck$ by an air pump1 a cl\dy light fill$ ! bulb1 :i* 0 !re=e call$ an electric egg4 ,hittorf & o!rs improv$ on ?is effect by employ+ ! sp>k f an induction coil & l>ge tubes1 highly exhau/$ ( air1 or conta9+ a r>e infusion ( o!r gases1 su* z hydrog54 ,by ?is means beautiful gl[s ( v>i\s col\rs1 resembl+ ! t5d] hues ( ! tropical sky1 or ! fleet+ t9ts ( ! aurora borealis1 7 produc$1 & h become famili> to u 9 ! well-kn[n ,geissl] tubes4 ,crookes1 ! celebrat$ ,engli% *emi/1 w5t /ill fur!r1 & by exhau/+ ! bulbs ) an improv$ ,spr5gel air-pump1 obta9$ an extremely high vacuum1 :i* gave rem>kable effects 7page #abj74 ,! diffus$ gl[ or cl\dy light ( ! tube n[ %rank into a s+le /ream1 :i* jo9$ ! sp>k+ po9ts ins]t$ ?r\gh ! ends ( ! tube z ) a lum9\s ?read ,a magnet held ne> ! tube b5t ! /ream] f its c\rse2 & !re 0 a d>k space or gap 9 x ne> ! negative po9t or ca?ode1 f :i* proce$$ invisible rays1 hav+ ! prop]ty ( impress+ a photographic plate1 & ( r5d]+ matt] 9 g5]al on :i* !y imp+$ phosphoresc5t1 &1 9 c\rse ( "t1 r$-hot4 ,:]e !y /rike on ! glass ( ! tube x is se5 to gl[ ) a gre5 or blui% phosphoresc5ce1 & x w ultimately s(t5 ) heat4 ,^! are ! fam\s ca?ode rays ( :i* we h rec5tly he>d s mu*4 ,app>5tly !y _c be produc$ except 9 a v high vacuum1 :]e ! pressure ( ! air is ab\t #a-ajj? million? ( an atmosph]e1 or t :i* x is "s #ij or #ajj miles above ! e>?4 ,mr ,crookes reg>ds !m z a /ream ( airy p>ticles electrifi$ by contact ) ! ca?ode or negative dis*>g+ po9t1 & repell$ f x 9 /raight l9es4 ,! r>ity ( ! air 9 ! tube enables ^! p>ticles to keep _! l9e )\t be+ jo/l$ by ! o!r p>ticles ( air 9 ! tube4 ,a molecul> bomb>dm5t f ! ca?ode is1 9 8 op9ion1 go+ on1 & :5 ! %ots1 t is to say1 ! molecules ( air1 /rike ! wall ( ! tube1 or any o!r body )9 ! tube1 ! %ock gives rise to phosphoresc5ce or fluoresc5ce & to heat4 ,?is1 9 brief1 is ! celebrat$ hypo!sis ( radiant matt]1 :i* has be5 support$ 9 ! ,unit$ ,k+dom by *ampions su* z ,"l ,kelv91 ,sir ,gabriel ,/okes1 & ,pr(essor ,fitzg]ald1 b que/ion$ abroad by ,gold/em1 ,jaumann1 ,wi$emann1 ,eb]t1 & o!rs4 ,l5>d1 a "y ,hung>ian1 pupil ( ! illu/ri\s ,he9ri* ,h]tz1 0 ! fir/ to inflict a s]i\s bl[ on ! hypo!sis1 by %[+ t ! ca?ode rays c\ld exi/ outside ! tube 9 air at ord9>y pressure4 ,h]tz _h f\nd t a ?9 foil ( alum9ium 0 p5etrat$ by ! rays1 & ,l5>d made a tube hav+ a w9d[ ( alum9ium1 ?r\gh :i* ! rays d>t$ into ! op5 air4 ,_! pa? c\ld be trac$ by ! blui% phosphoresc5ce :i* !y excit$ 9 ! air1 & he succe$$ 9 gett+ !m to p5etrate a ?9 metal box & take a photograph inside x4 ,b if ! rays are a /ream ( radiant matt] :i* c only exi/ 9 a high vacuum1 h[ c !y survive 9 air at ord9>y pressure8 ,l5>d's exp]im5ts c]ta9ly fav\r ! hypo!sis ( _! be+ waves 9 ! lum9if]\s e!r4 ,pr(essor ,rontg51 ( ,wirzburg1 pr(it+ by ,l5>d's results1 accid5tally discov]$ t ! rays com+ f a ,crookes tube1 ?r\gh ! glass itself1 c\ld photograph ! bones 9 ! liv+ h&1 co9s inside a purse1 & o!r objects cov]$ up or hid 9 ! d>k4 ,"s bodies1 su* z fle%1 pap]1 wood1 ebonite1 or vulcanis$ fibre1 ?9 %eets ( metal1 & s on1 are m or less transp>5t1 & o!rs1 su* z bones1 c>bon1 qu>tz1 ?ick plates ( metal1 are m or less opaque to ! rays4 ,! human h&1 = example1 consi/+ ( fle% & bones1 all[s ! rays to pass easily ?r\gh ! fle%1 b n ?r\gh ! bones4 ,consequ5tly1 :5 x is int]pos$ betwe5 ! rays & a photographic plate1 ! skeleton inside is photograph$ on ! plate4 ,a lead p5cil photograph$ 9 ?is way %[s only ! black lead1 & a razor ) a horn h&le only ! blade4 ,?anks to ! c\rtesy ( ,mr4 ,a4 ,a4 ,campbell ,sw9ton1 ( ! firm ( ,sw9ton ,/anton1 ! well-kn[n electrical eng9e]s1 ( ,victoria ,/reet1 ,we/m9/]1 a skilful exp]im5tali/1 :o 0 ! fir/ to turn to ! subject 9 ,engl&1 ,i h witness$ ! tak+ ( ^! %ad[ photographs1 z !y are call$1 some:at errone\sly1 = radiographs or cryptographs w\ld be a bett] ^w1 & %all briefly describe 8 me?od4 ,rontg5 employs an induction coil insulat$ 9 oil to excite ! ,crookes tube & yield ! rays1 b ,mr4 ,sw9ton uses a high frequ5cy curr5t1 obta9$ f app>atus simil> to t ( ,tesla1 & %[n 9 figure #ajj1 namely1 a high frequ5cy induction coil insulat$ by means ( oil & excit$ by ! cont9u\s dis*>ge ( twelve half-gallon ,leyd5 j>s *>g$ by an alt]nat+ curr5t at a pressure ( #bj1jjj volts produc$ by an ord9>y l>ge induction coil sp>k+ across its high pressure t]m9als4 ,a vacuum bulb connect$ betwe5 ! dis*>ge t]m9als ( ! high frequ5cy coil1 z %[n 9 figure #aja1 0 illum9at$ ) a p9k gl[1 :i* /ream$ f ! negative to ! positive pole--t is to say1 ! ca?ode to ! anode1 & ! glass became lum9\s ) blui% phosphoresc5ce & gre5i% fluoresc5ce4 ,imm$iately "u ! bulb 0 plac$ my nak$ h& re/+ on a photographic slide conta9+ a s5sitive bromide plate cov]$ ) a plate ( vulcanis$ fibre4 ,an exposure ( five or t5 m9utes is suffici5t to give a good picture ( ! bones1 z w be se5 f ! frontispiece4 ,! t]m %ad[ photograph requires a ^w ( explanation4 ,! bones d n appe> z flat %ad[s1 b r\nd$ l solid bodies1 z ?\gh ! active rays pass$ ?r\gh _! sub/ance4 ,accord+ to ,rontg51 ^! x rays1 z he calls !m1 are n true ca?ode rays1 p>tly because !y are n deflect$ by a magnet1 b ca?ode rays trans=m$ by ! glass ( ! tube2 & !y are probably n ultra-violet rays1 because !y are n refract$ by wat] or reflect$ f surfaces4 ,he ?9ks !y are ! miss+ longitud9al rays ( light ^: exi/5ce has be5 conjectur$ by ,"l ,kelv9 & o!rs--t is to say1 waves 9 :i* ! e!r sways to & fro along ! direction ( ! ray1 z 9 ! case ( s\nd vibrations1 & n f side to side across x z 9 ord9>y light4 ,be ?is z x may1 8 discov]y has op5$ up a new field ( rese>* & inv5tion4 ,x has be5 f\nd t ! imm$iate s\rce ( ! rays is ! fluoresc5ce & phosphoresc5ce ( ! glass1 & !y are m effective :5 ! fluoresc5ce is gre5i%-yell[ or can>y col\r4 ,c]ta9 salts--= example1 ! sulphates ( z9c & ( calcium1 b>ium plat9o-cyanide1 tung/ate ( calcium1 & ! d\ble sulphate ( uranyle & potassium--are m active ?an glass1 & ev5 emit ! rays aft] exposure to ord9>y light1 if n also 9 ! d>k4 ,salvioni ( ,p]ugia has inv5t$ a cryptoscope1 :i* enables u to see ! hidd5 object )\t ! aid ( photography by all[+ ! rays to fall on a plate coat$ ) "o ( ^! phosphoresc5t sub/ances4 ,already ! new me?od has be5 appli$ by doctors 9 exam9+ mal=mations & diseases ( ! bones or int]nal organs1 & 9 localis+ & extract+ bullets1 ne$les1 or o!r =eign matt]s 9 ! body4 ,!re is little d\bt t x w be v useful z an adjunct to hospitals1 especially 9 w>f>e1 &1 if ! app>atus c be r$uc$ 9 size1 x w be employ$ by ord9>y practition]s4 ,x has also be5 us$ to photograph ! skeleton ( a mummy1 & to detect true f artificial gems4 ,h[ev]1 "o _c n[ easily pr$ict its future value1 & applications w be f\nd out "o aft] ano!r z "t goes on4 ,,*apt] ,x4 ,,! ,,wireless ,,telegraph4 ,magnetic waves g5]at$ 9 ! e!r 7see pp4 #ec-ie7 by an electric curr5t fl[+ 9 a conductor are n ! only waves :i* c be set up 9 x by aid ( electricity4 ,a m]ely /ation>y or /atic *>ge ( electricity on a body1 say a brass ball1 c also di/urb ! e!r2 & if ! /r5g? ( ! *>ge is v>i$1 e!r oscillations or waves are excit$4 ,a simple way ( produc+ ^! electric waves 9 ! e!r is to v>y ! /r5g? ( *>ge by draw+ sp>ks f ! *>g$ body4 ,( c\rse ?is c be done accord+ to ! ,morse code2 & z ! waves aft] travell+ ?r\gh ! e!r ) ! spe$ ( light are capable ( influ5c+ conductors at a di/ance1 x is easy to see t signals c be s5t 9 ?is way4 ,! fir/ to d s 9 a practical mann] 0 ,sign] ,m>coni1 a "y ,italian hi!rto unkn[n to fame4 ,9 c>ry+ out 8 inv5tion1 ,m>coni made use ( facts well kn[n to !oretical electricians1 "o ( :om1 ,dr1 ,oliv] ,j4 ,lodge1 _h ev5 s5t signals ) !m 9 #ahid2 b x (t5 happ5s 9 sci5ce z 9 lit]ature t ! recognis$ pr(essors1 ! m5 :o seem to h ev]y?+ 9 _! fav\r--k1 ev5 tal5t--! m5 :om mo/ p w\ld expect to give u an orig9al discov]y or inv5tion1 are beat5 by an outsid] :om nobody he>d (1 :o _h nei!r le>n+1 leisure1 nor app>atus1 b :at he c\ld pick up = himself4 ,m>coni produces 8 waves 9 ! e!r by electric sp>ks pass+ betwe5 f\r brass balls1 a device ( ,pr(essor ,righi1 foll[+ ! classical exp]im5ts ( ,he9ri* ,h]tz4 ,! balls are electrifi$ by connect+ !m to ! well-kn[n in/rum5t call$ an induction coil1 sometimes us$ by physicians to adm9i/] g5tle %ocks to invalids2 & z ! work+ ( ! coil is />t$ & /opp$ by an ord9>y telegraph key = int]rupt+ ! electric curr5t1 ! sp>k+ c be controll$ accord+ to ! ,morse code4 ,9 our diagram1 :i* expla9s ! app>atus1 ! f\r balls are se5 at ,d1 ! inn] & l>g] pair be+ p>tly imm]s$ 9 vasel9e oil1 ! out] & small] pair be+ connect$ to ! second>y or induc$ circuit ( ! induction coil ,c1 :i* is repres5t$ by a wavy l9e4 ,! prim>y or induc+ circuit ( ! coil is connect$ to a batt]y ,b ?r\gh a telegraph signall+ key ,k1 s t :5 ?is key is op5$ & clos$ by ! telegraphi/ accord+ to ! ,morse code1 ! induction coil is excit$ = a long] or %ort] "t by ! curr5t f ! batt]y1 9 agreem5t ) ! long] & %ort] signals ( ! message4 ,at ! same "t long] or %ort] s]ies ( sp>ks correspond+ to ^! signals pass across ! gaps betwe5 ! f\r balls1 & give rise to long] or %ort] s]ies ( e!ric waves repres5t$ by ! dott$ l9e4 ,s mu* = ! ,transmitt]4 ,b h[ does ,m>coni trans=m ^! invisible waves into visible or audible signals at ! di/ant place8 ,he does ?is by virtue ( a prop]ty discov]$ by ,mr4 ,s4 ,a4 ,v>ley z f> back z #ahff1 & inve/igat$ by ,mr4 ,e4 ,branly 9 #ahhi4 ,!y f\nd t p[d] ( metals1 c>bon1 & o!r conductors1 :ile (f]+ a great resi/ance to ! passage ( an electric curr5t :5 9 a loose /ate1 coh]es toge!r :5 electric waves act ^u x1 & opposes mu* less resi/ance to ! electric curr5t4 ,x foll[s t if a ,morse telegraph in/rum5t at ! di/ant place be connect$ 9 circuit ) a batt]y & "s loose metal du/1 x c be adju/$ to "w :5 ! e!ric waves pass ?r\gh ! du/1 & only !n4 ,9 ! diagram ,r is ?is ,morse ,receiv] jo9$ 9 circuit ) a batt]y ,b#a2 & a ?9 lay] ( nickel & silv] du/1 mix$ ) a trace ( m]cury1 is plac$ betwe5 two cyl9drical knobs or electrodes ( silv] fus$ into ! glass tube d1 :i* is exhau/$ ( air l an electric gl[ lamp4 ,n[1 :5 ! e!ric waves proce$+ f ! transmitt+ /ation trav]se ! glass ( ! tube & act ^u ! metal du/1 ! curr5t ( ! batt]y ,b#a works ! ,morse receiv]1 & m>ks ! signals 9 ink on a /rip ( travell+ pap]4 ,inasmu* z ! du/ t5ds to /ick toge!r aft] a wave passes ?r\gh x1 h[ev]1 x requires to be %ak5 loose aft] ea* signal1 & ?is is done by a small r\nd hamm] head se5 on ! "r1 :i* gives a slight tap to ! tube4 ,! hamm] is work$ by a small electromagnet ,e1 connect$ to ! ,morse in/rum5t1 & ano!r batt]y b 9 :at is call$ a relay circuit2 s t aft] ! ,morse in/rum5t m>ks a signal1 ! hamm] makes a tap on ! tube4 ,z ?is tap has a bell-l s\nd1 ! telegraphi/ c also read ! signals ( ! message by 8 e>4 ,two self-induction bobb9s1 ,l ,ll1 a well-kn[n device ( electricians = oppos+ resi/ance to electric waves1 are includ$ 9 ! circuit ( ! ,morse in/rum5t ! bett] to conf9e ! action ( ! waves to ! p[d] 9 ! tube4 ,fur!r1 ! tube d is connect$ to two metal conductors ,v ,vl1 :i* may be comp>$ to resonators 9 music4 ,!y c be adju/$ or attun$ to ! electric waves z a /r+ or pipe is to sonor\s waves4 ,9 ?is way ! receiv] c be made to "w only :5 electric waves ( a c]ta9 rate are pass+ ?r\gh ! tube1 j z a tun+-=k res\nds to a c]ta9 note2 x be+ und]/ood t ! l5g? ( ! waves c be regulat$ by adju/+ ! balls ( ! transmitt]4 ,z ! e!ric waves produc$ by ! sp>ks1 l ripples ( wat] caus$ by dropp+ a /one into a pool1 travel 9 all directions f ! balls1 a s+le transmitt] c "w a numb] ( receiv]s at diff]5t /ations1 provid$ ^! are tun$ by adju/+ ! conductors ,v ,vl to ! l5g? ( ! waves4 ,?is inde$ 0 ! condition ( affairs at ! "t :5 ! "y ,italian transmitt$ messages f ,france to ,engl& 9 ,m>*1 #ahii1 & x is a me?od t s9ce has be5 f\nd useful ov] limit$ di/ances4 ,b to ! inv5tor !re seem$ no reason :y wireless telegraphy %\ld be limit$ by any su* di/ances4 ,accord+ly he imm$iately develop$ 8 me?od & 8 app>atus1 hav+ 9 m9d ! transmission ( signals ov] consid]able int]vals4 ,! fir/ "q t arose 0 ! effect ( ! curvature ( ! ,e>? & :e!r ! waves foll[ ! surface ( ! ,e>? or 7 propagat$ 9 /raight l9es1 :i* w\ld require ! erection ( a]ial t[]s & wires ( consid]able height4 ,!n !re 0 ! "q ( ! am\nt ( p[] involv$ & :e!r g5]ators or o!r devices c\ld be us$ to furni% waves ( suffici5t int5sity to trav]se consid]able di/ances4 ,little by little progress 0 made & 9 ,janu>y1 #aija1 wireless communication 0 e/abli%$ betwe5 ! ,isle ( ,wight & ,liz>d 9 ,cornwall1 a di/ance ( #ahf miles ) t[]s less ?an #cjj feet 9 height1 s t x 0 demon/rat$ t ! curvature ( ! ,e>? did n s]i\sly affect ! transmission ( ! waves1 z t[]s at lea/ a mile high w\ld h be5 requir$ 9 case ! waves 7 s cut (f4 ,?is 0 a s\rce ( consid]able enc\ragem5t to ,m>coni1 & 8 app>atus 0 fur!r improv$ s t ! resonance ( ! circuit & ! v>iation ( ! capacity ( ! prim>y circuit ( ! oscillation trans=m] made = increas$ effici5cy4 ,! coh]] 0 /ill reta9$ & by ! end ( #aijj en\gh _h be5 accompli%$ to w>rant ,m>coni 9 arrang+ = trans-,atlantic exp]im5ts betwe5 ,poldhu1 ,cornwall & ! ,unit$ ,/ates1 /ations be+ locat$ on ,cape ,cod & 9 ,newf\ndl&4 ,! trans-,atlantic transmission ( signals 0 q a diff]5t matt] f work+ ov] #ajj miles or s 9 ,great ,brita94 ,! s+le a]ial wire 0 supplant$ by a set ( fifty almo/ v]tical wires1 support$ at ! top by a horizontal wire /ret*$ betwe5 two ma/s #aeg #a_/b feet high & #eb #a_/b feet ap>t1 conv]g+ toge!r at ! l[] end 9 ! %ape ( a l>ge fan4 ,! capacity ( ! cond5s] 0 increas$ & in/ead ( ! batt]y a small g5]ator 0 employ$ s t a sp>k #a #a_/b in*es 9 l5g? w\ld be dis*>g$ betwe5 sph]es #c in*es 9 diamet]4 ,at ! end ( ! ye> #aija tempor>y /ations at ,newf\ndl& 7 e/abli%$ & exp]im5ts 7 c>ri$ on ) a]ial wires rais$ 9 ! air by means ( kites4 ,x 0 "h realiz$ t v>i\s ref9em5ts 9 ! receiv+ app>atus 7 necess>y1 & in/ead ( ! coh]] a telephone 0 ins]t$ 9 ! second>y circuit ( ! oscillation trans=m]1 & ) ?is device on ,febru>y #ab? ! fir/ signals to be transmitt$ across ! ,atlantic 7 he>d4 ,^! e>ly exp]im5ts 7 s]i\sly affect$ by ! fact t ! ant5nae or a]ial wires 7 con/antly v>y+ 9 height ) ! movem5t ( ! kites1 & x 0 f\nd t a p]man5t arrangem5t ( receiv+ wires1 indep5d5t ( kites or balloons1 0 ess5tial4 ,yet x 0 demon/rat$ at ?is "t t ! transmission ( electric waves & _! detection ov] di/ances ( #bjjj miles 0 di/9ctly possible4 ,a m sy/ematic & ?or\gh te/ occurr$ 9 ,febru>y1 #aijb1 :5 a receiv+ /ation 0 in/all$ on ! /eam%ip ,philadelphia1 proce$+ f ,s\?ampton to ,new ,york4 ,! receiv+ a]ial 0 rigg$ to ! ma9ma/1 ! top ( :i* 0 #aig feet above ! level ( ! sea1 & a syntonic receiv] 0 employ$1 enabl+ ! signals to be record$ on ! tape ( an ord9>y ,morse record]4 ,on ?is voyage readable messages 7 receiv$ f ,poldhu up to a di/ance ( #aeea miles1 & te/ lett]s 7 receiv$ z f> z #bjii miles4 ,x 0 on ?is voyage t ,m>coni made ! int]e/+ discov]y ( ! effect ( sunlight on ! propagation ( electric waves ov] great di/ances4 ,he f\nd t ! waves 7 absorb$ dur+ ! daytime mu* m ?an at night & he ev5tually rea*$ ! conclusion t ! ultraviolet light f ! sun ioniz$ ! gase\s molecules ( ! air1 & ioniz$ air absorbs ! en]gy ( ! electric waves1 s t ! fact 0 e/abli%$ t cle> sunlight & blue skies1 ?\gh transp>5t to light1 s]ve z a fog to ! p[]ful ,h]tzian waves ( wireless telegraphy4 ,= t reason ! transmission ( messages is c>ri$ on ) great] facility on ! %ores ( ,engl& & ,newf\ndl& across ! ,nor? ,atlantic ?an 9 ! cle>] atmosph]e ( l[] latitudes4 ,b atmosph]ic conditions d n affect all =ms ( waves ! same1 & long waves ) small amplitudes are f> less subject to ! effect ( daylight ?an ^? ( l>ge amplitude & %ort wave l5g?1 & g5]ators & circuits 7 arrang$ to produce ! =m]4 ,b ! difficulty did n prove insup]able1 z ,m>coni f\nd t increas+ ! en]gy ( ! transmitt+ /ation dur+ ! daytime w\ld m ?an make up = ! loss ( range4 ,! exp]im5ts begun at ,newf\ndl& 7 transf]r$ to ,nova ,scotia1 & at ,glace ,bay 9 #aijb 0 e/abli%$ a /ation f :i* messages 7 transmitt$ & exp]im5tal "w c>ri$ on until its "w 0 tempor>ily int]rupt$ by fire 9 #aiji4 ,"h f\r wood5 lattice t[]s1 ea* #baj feet 9 height1 7 built at ! corn] ( a squ>e #bjj feet on a side1 & a conical arrangem5t ( #djj copp] wires support$ on /ays betwe5 ! tops ( ! t[]s & connect$ 9 ! middle at ! g5]at+ /ation 0 built4 ,additional ma*9]y 0 in/all$ & at ! same "t a /ation at ,cape ,cod = comm]cial "w 0 built4 ,9 ,decemb]1 #aijb1 regul> communication 0 e/abli%$ betwe5 ,glace ,bay & ,poldhu1 b x 0 only satisfactory f ,canada to ,engl& z ! app>atus at ! ,poldhu /ation 0 less p[]ful & effici5t ?an t in/all$ 9 ,canada4 ,! transmission ( a message f ,presid5t ,roosevelt to ,k+ ,edw>d m>k$ ! practical beg9n+ ( trans-,atlantic wireless telegraphy4 ,by ?is "t a new device = ! detection ( messages 0 employ$1 z ! coh]] we h describ$ ev5 9 its improv$ =ms 0 f\nd to possess its limitations ( s5sitiv5ess & did n respond satisfactorily to long di/ance signals4 ,a magnetic detector 0 devis$ by ,m>coni :ile o!r inv5tors _h contriv$ electrolytic1 m]curial1 !rmal1 & o!r =ms ( detector1 us$ = ! mo/ "p ) a telephone receiv] 9 ord] to detect m9ute v>iations 9 ! curr5t caus$ by ! reception ( ! electro-magnetic waves4 ,) "o ( ,m>coni's magnetic detectors signals f ,cape ,cod 7 read at ,poldhu4 ,9 #aijc wireless telegraphy _h rea*$ su* a developm5t t ! transmission ( news messages 0 attempt$ 9 ,m>* & ,april ( t ye>4 ,b ! s]vice 0 susp5d$1 ow+ to defects :i* manife/$ !mselves 9 ! app>atus1 & 9 ! meantime a new /ation 9 ,irel& 0 erect$4 ,b !re 0 no cessation ( ! practical exp]im5ts c>ri$ on1 & 9 #aijc ! ,cun>d /eam%ip ,lucania receiv$1 dur+ h] entire voyage across f ,new ,york to ,liv]pool1 news transmitt$ direct f %ore to %ore4 ,9 ! meantime int]communication betwe5 %ips _h be5 develop$ & ! use ( wireless 9 naval op]ations 0 recogniz$ z a necessity4 ,v>i\s improvem5ts f "t to "t 7 made 9 ! a]ial wires1 & 9 #aije a numb] ( horizontal wires 7 connect$ to an a]ial ( ! inv]t$ cone type previ\sly us$4 ,! directional a]ial ) ! horizontal wires 0 tri$ at ,glace ,bay1 & adopt$ = all ! long di/ance /ations1 af=d+ consid]able /r5g!n+ ( ! receiv$ signals at ,poldhu /ations4 ,likewise improvem5ts 9 ! app>atus 7 effect$ at bo? trans-,atlantic /ations1 consi/+ ( ! adoption ( air cond5s]s compos$ ( insulat$ metallic plate susp5d$ 9 ! air1 :i* 7 f\nd mu* bett] ?an ! cond5s]s :]e glass 0 previ\sly us$ to sep>ate ! plates4 ,= produc+ ! en]gy employ$ = transmitt+ ! signals a high t5sion cont9u\s curr5t dynamo is us$4 ,an oscillatory curr5t ( high pot5tial is produc$ 9 a circuit :i* consi/s ( rapidly rotat+ disks 9 connection ) ! dynamo & suitable cond5s]s4 ,! production ( electric oscillations c be accompli%$ 9 sev]al ways & waves ( ! desir$ frequ5cy & amplitude produc$4 ,?us 9 #aijc x 0 f\nd by ,p\ls51 elaborat+ on a pr9ciple fir/ discov]$ by ,duddell1 t an oscillatory curr5t may be d]iv$ f an electric arc ma9ta9$ "u c]ta9 conditions & t undamp$ high frequ5cy waves s produc$ 7 suitable = wireless telegraphy4 ,?is discov]y 0 ( importance1 z x 0 f\nd t ! waves s g5]at$ 7 undamp$1 t is1 capable ( proce$+ to _! de/9ation )\t loss ( amplitude4 ,on ?is acc\nt !y 7 especially suitable = wireless telephony :]e !y 7 e>ly appli$1 z x 0 f\nd possible s to arrange a circuit ) an ord9>y microphone transmitt] t ! amplitude ( ! waves w\ld be v>i$ 9 h>mony ) ! vibrations ( ! human voice4 ,^! waves s modulat$ c\ld be receiv$ by "s =m ( s5sitive wave detector at a di/ant /ation & reproduc$ 9 ! =m ( s\nd ) an ord9>y telephone receiv]4 ,) undamp$ waves f ! arc & f special =ms ( g5]ators wireless telephony ov] di/ances z great z #bjj miles has be5 accompli%$ & ov] %ort] di/ances1 especially at sea & = sea to %ore1 communication has f\nd consid]able application4 ,x is1 h[ev]1 an art t is j at ! beg9n+ ( its usefulness1 /&+ 9 mu* ! same relation to wireless telegraphy t ! ord9>y telephone does to ! famili> sy/em employ+ metallic conductors4 ,on ! sp>k & arc sy/ems v>i\s me?ods ( wireless telegraphy h be5 develop$ & improv$ s t ,m>coni no long] has any monopoly ( me?ods or in/rum5ts4 ,v>i\s companies & gov]nm5t (ficials h devis$ or modifi$ sy/ems s t to-day wireless is practically univ]sal & is gov]n$ by an int]national conv5tion to :i* lead+ nations ( ! _w subscribe4 ,"o ( ! rec5t features ( wireless telegraphy ( int]e/ is ! success ( v>i\s directional devices4 ,z we h se51 v>i\s s*emes 7 tri$ by ,m>coni rang+ f metallic reflectors us$ by ,h]tz 9 8 e>ly exp]im5ts ) ! electric waves to ! m successful arrangem5t ( a]ial conductors4 ,9 ,europe ,bell9i & ,tosi h develop$ a me?od = obta9+ direct$ a]ial waves :i* promises to be ( consid]able utility1 enabl+ !m to be project$ 9 a s+le direction j z a se>*light beam & ?us re/rict ! numb] ( po9ts at :i* ! signals c\ld be int]cept$ & read4 ,likewise an arrangem5t 0 p]fect$ :i* enabl$ a /ation to det]m9e ! direction 9 :i* ! waves 7 be+ project$ & consequ5tly ! be>+ ( ano!r vessel or ligh?\se or o!r /ation4 ,! fundam5tal pr9ciple 0 ! arrangem5t ( ! ant5nae1 two triangul> sy/ems be+ provid$ on ! same ma/1 b 9 "o ! curr5t is br\ght d[n 9 a p]p5dicul> direction4 ,! action dep5ds ^u ! diff]5ce ( ! curr5t 9 ! two triangles4 ,wireless telegraph app>atus is f\nd in/all$ 9 almo/ e seago+ pass5g] vessel ( l>ge size engag$ 9 regul> traffic1 & z a means ( safety z well z a conv5i5ce its usefulness has be5 demon/rat$4 ,?us on ! ,nor? ,atlantic ! l>ge/ l9]s are nev] out ( t\* ) l& on "o side ( ! ocean or ! o!r1 & news is suppli$ = daily pap]s :i* are publi%$ on %ipbo>d4 ,e %ip 9 ?is "p ( ! ocean equipp$ ) ! ,m>coni sy/em1 = example1 is 9 communication on an av]age ) f\r vessels suppli$ ) in/rum5ts ( ! same sy/em e tw5ty-f\r h\rs4 ,9 case ( dang] or disa/] signals go+ out ov] ! sea spe$ily c br+ succ\r1 z cle>ly 0 demon/rat$ 9 ! case ( ! collision betwe5 ! ,:ite ,/> /eam%ip ,republic & ! /eam%ip ,florida on ,janu>y #bf1 #aiji4 ,"h wireless dang] messages 7 s5t out z long z ! ,republic 0 afloat & its wireless app>atus work+4 ,^! br\ght aid f v>i\s /eam]s 9 ! vic9ity & ! pass5g]s 7 spe$ily transf]r$ f ! s9k+ ,republic4 ,on ,april #ae1 #aiab1 ! ,:ite ,/> l9] ,titanic1 ! l>ge/ %ip afloat1 sank (f ,newf\ndl&1 aft] collid+ ) an iceb]g4 ,wireless ,,sos calls = help br\ght sev]al /eam%ips to ! sc5e1 & #gjc p]sons f a total ( #b1bjf1 7 rescu$4 ,on ,octob] #i1 #aiac1 ! ,uranium l9] ,volturno caught fire 9 mid- ocean1 & h] wireless calls br\ght t5 /eam%ips to h] aid1 :i*1 despite a heavy sea1 rescu$ #ecb p]sons f a total ( #feg4 ,aga91 on ,novemb] #ad1 #aiac1 ! ,spani% /eam%ip ,balmes caught fire (f ,b]muda1 & at h] wireless call ! ,cun>d l9] ,pannonia sav$ all ( h] pass5g]s--#ajc4 ,! ,titanic horror l$ ! pr9cipal m>itime nations to take imm$iate /eps to p]fect _! wireless sy/ems1 & ! in/allation ( app>atus & op]ators soon became a prime requisite ( ! equipm5t ( ! _w's %ipp+4 ,wireless telegraphy has be5 develop$ to great effici5cy 9 all ! lead+ navies1 & p[]ful plants are in/all$ on all w>%ips4 ,! ,unit$ ,/ates1 ,great ,brita91 & ,g]many1 mo/ noticeably1 h e/abli%$ %ore /ations1 by :i* !y c talk all ar\nd ! _w f any %ip or /ation4 ,9 op]ation secrecy is mo/ important4 ,= 9 ! navy practically all important messages are s5t 9 code or ciph] "u all conditions :ile 9 comm]cial "w ! tapp+ ( l& wires or ! /eal+ ( messages :ile illegal is physically possible = ! evil dispos$ yet has nev] prov$ 9 practice a s]i\s evil4 ,! problem ( int]f]5ce1 h[ev]1 seems to h be5 fairly solv$ by ! l>ge sy/ems ?\gh ! activity ( amateurs is (t5 a s]i\s di/urbance = gov]nm5t & o!r /ations4 ,despite ! progress ( wireless telegraphy x has n yet supplant$ ! subm>9e cable & ! l& wire1 & 9 cons]vative op9ion x w be _m ye>s be=e x w d s4 ,9 fact1 s9ce ,m>coni's "w !re has be5 no dim9ution 9 ! numb] or am\nt ( cables laid & ! bus9ess h&l$1 nor is !re prospect ( su* = ye>s to come4 ,:ile ! cable has answ]$ admirably = telegraphic purposes yet = telephony ov] consid]able di/ances x has fail$ entirely s t wireless telephony ov] oceans />ts ) a m ?an favorable outlook4 ,b wireless telegraphy to a l>ge ext5t has made its own field & "h its "w has be5 greatly successful4 ,?us :5 ,pe>y's message ann\nc+ 8 discov]y ( ! ,nor? ,pole came out ( ! ,froz5 ,nor?1 x 0 by way ( ! wireless /ation on ! di/ant ,labrador coa/ t x rea*$ an anxi\s & int]e/$ civilization4 ,x is ?is same wireless t wat*es ! progress ( ! fi%+ fleets at /ations :]e comm]cial consid]ations w\ld r5d] impossible ! ma9t5ance ( a subm>9e cable4 ,x is ! wireless telegraph t ma9ta9s communication 9 ! int]ior ( ,alaska & betwe5 isl&s 9 ! ,pacific & else:]e :]e conditions ( developm5t d n p]mit ( ! m exp5sive in/allation ( subm>9e cable or climatic or o!r conditions r5d] impossible ov]l& l9es4 ,at sea its advantages are obvi\s4 ,ev]y:]e ! e!r responds to ! impulses ( ! crackl+ sp>ks1 & ev5 f ! air%ip we soon may expect wireless messages z ! few untrodd5 regions ( our globe are explor$4 ,,*apt] ,,xl ,,electro-,,*emi/ry ,,& ,,electro-,,metallurgy4 ,9 no dep>tm5t ( ! application ( electricity to practical "w has !re be5 a great] developm5t ?an 9 electro- metallurgy & electro-*emi/ry4 ,to-day !re are va/ indu/ries dep5d+ ^u electrical processes & ! developm5ts ( a qu>t] ( a c5tury h be5 truly rem>kable4 ,already m ?an "o-half ( ! copp] us$ 9 ! arts is d]iv$ by electrolytic ref9+4 ,! production ( alum9um dep5ds entirely on electricity1 ! electric furnace z a possible rival to ! bla/ furnace = ! production ( iron & /eel is be+ s]i\sly consid]$1 & _m o!r metallurgical processes are be+ und]tak5 on a l>ge scale4 ,we h se5 9 our *apt] on ,electrolysis h[ a metal may be deposit$ f a solution ( its salt & h[ ?is process c\ld be us$ = d]iv+ a pure metal or = plat+ or coat+ ) ! desir$ metal ! surface ( ano!r metal or "o cov]$ ) graphite4 ,9 ! foll[+ pages x is int5d$ to take up "s ( ! m notable accompli%m5ts 9 ?is field a*iev$ by electricity1 :i* h be5 develop$ to a /ate ( comm]cial importance4 ,! electric arc n only supplies light1 b heat ( great int5sity :i* ! electrical eng9e] z well z ! pure sci5ti/ has f\nd s valuable = _m practical op]ations4 ,x is ( c\rse obvi\s t = mo/ *emical op]ations1 & especially 9 ! field ( metallurgy1 heat is requir$ = ! sep>ation ( comb9ations ( v>i\s elem5ts1 = _! purification1 z well z = ! comb9ation ) o!r elem5ts into alloys or comp\nds ( direct utility4 ,! usual me?od ( g5]at+ heat is by ! combu/ion ( "s fuel1 su* z coal1 coke1 gas or oil1 & ?is has be5 utiliz$ = hundr$s ( ye>s 9 smelt+ metals & ores & 9 ref9+ ! mat]ial f a crude /ate4 ,n[ x may happ5 t a nation or region may be ri* 9 metallif]\s ores1 b possess few1 if any1 coal deposits4 ,accord+ly ! ore mu/ be m9$ & transport$ consid]able di/ances = treatm5t & ! advantages ( manufactur+ indu/ries are lo/ to ! neighborhood ( its orig9al production4 ,b if wat] p[] is available1 z x is 9 _m m\nta9\s c\ntries :]e v>i\s ores are f\nd1 !n ?is p[] c be trans=m$ into electricity :i* is available z p[] n only 9 v>i\s manufactur+ op]ations1 b = prim>y metallurgical "w 9 smelt+ ! ores & obta9+ ! metal !refrom4 ,a /rik+ in/ance ( ?is is ! k+dom ( ,sw$51 :i* conta9s b little coal1 yet is ri* 9 m9]als & 9 wat] p[]1 s t its wat]falls h be5 picturesquely allud$ to z ! c\ntry's :ite coal4 ,likewise1 at ,niag>a ,falls a portion ( ! va/ wat] p[] develop$ !re has be5 us$ 9 ! manufacture ( alum9um1 calcium c>bide1 c>borundum1 & o!r mat]ials1 :ile at o!r po9ts 9 ! ,unit$ ,/ates & ,canada1 n to m5tion ,europe1 l>ge indu/ries :]e electricity is us$ = metallurgical or *emical "w are c>ri$ on & ! erection ( new plants is contemplat$4 ,! application ( electricity to metallurgical & *emical "w has be51 9 ne>ly all cases1 ! result ( sci5tific rese>*1 & elaborate exp]im5tal laboratories are ma9ta9$ by ! v>i\s corporations int]e/$ 9 ! pres5t or future use ( electrical processes4 ,x is recogniz$ by _m ( ! old] work]s 9 ?is field t electrical developm5ts are b\nd to come 9 ! ne> future1 & :ile !y h n in/all$ su* appliances 9 _! works yet !y are keep+ close wat* ( pres5t developm5ts1 & 9 _m cases exp]im5tal inve/igation & rese>* is be+ c>ri$ on :]e electrical me?ods h n yet be5 introduc$ g5]ally into ! plant4 ,prior to #ahhf ! ref9+ ( copp] 0 ! only electro- metallurgical indu/ry & at t "t x 0 c>ri$ on on a v limit$ scale4 ,to-day ! production ( electrolytic copp] z an indu/ry is second 9 importance only to ! actual production ( t metal4 ,f ! small ref9]y />t$ by ,james ,elk+ton at ,pembury 9 ,s\? ,wales1 a va/ indu/ry has develop$ 9 :i* !re has be5 a *ange 9 ! size ( op]ations & 9 ! details ( me?ods r ?an 9 ! fundam5tal process4 ,= a solution ( copp] sulphate is employ$ z ! electrolyte1 blocks ( raw copp] z ! anodes1 & ?9 %eets ( pure copp] z ! ca?odes4 ,! passage ( ! electric curr5t1 z we h se5 on page #gi1 9 ! *apt] on ,electrolysis1 is able to decompose ! copp] 9 ! electrolyte & to precipitate *emically pure copp] on ! ca?ode1 ! copp] ( ! solution be+ repl5i%$ f ! raw mat]ial us$ z ! anode by :i* ! curr5t is pass$ into ! ba?4 ,at ?is ,wel% factory #bej tons ye>ly 7 produc$1 & small e>!nw>e pots suffic$ = ! electrolyte4 ,?irty ye>s lat] "o ,am]ican factory alone 0 able to produce at lea/ #cej tons ( electrolytic copp] 9 tw5ty-f\r h\rs1 & ov] #djj1jjj tons is ! aggregate output ( ! ref9]ies ( ! _w1 :i* is ab\t #ec p] c5t1 ( ! total raw copp] production4 ,( ?is am\nt #he p] c5t1 comes f ,am]ican ref9]ies1 ^: output has m ?an d\bl$ s9ce #aijj4 ,! *ief reason = ?is increas$ output ( electrolytic copp] has be5 ! great dem& = its use 9 ! electrical indu/ries :]e n only a va/ am\nt is consum$1 b :]e copp] ( high purity1 to give ! maximum conductivity requir$ by ! electrical eng9e]1 is dem&$4 ,:5 x is realiz$ t e dynamo is w\nd ) copp] wire & t ! same mat]ial is us$ = ! trolley wire & = ! di/ribution wires 9 electric light+1 x w be app>5t h[ ! dem& = copp] has increas$ 9 ! la/ qu>t] ( a c5tury4 ,electrolytic me?ods n only supply a pur] article & are economical to op]ate1 especially if !re is wat] p[] 9 ! vic9ity1 b ! copp] ores conta9 v>y+ am\nts ( silv] & gold :i* c be recov]$ f ! slimes obta9$ 9 ! electrolytic process4 ,:]ev] possible ma*9]y has be5 sub/itut$ = h& labor1 ! raw copp] anodes h be5 ca/1 & ! *>g+ & dis*>g+ ( ! vats is c>ri$ on by ! mo/ mod]n me*anical me?ods 9 :i* effici5cy & economy are secur$4 ,on ! *emical side ( ! process attempts h be5 made to improve ! electrolyte1 notably by ! addition ( a small am\nt ( hydro*loric acid to prev5t ! loss ( silv] 9 ! slimes1 & ?is "p ( ! "w is wat*$ ) q z mu* c>e z ! o!r /ages4 ,electric furnaces h also be5 con/ruct$ = smelt+ copp] ores1 b ^! h n f\nd wide application1 & ! problem is "o ( ! future4 ,= ! mo/ "p ! copp] electrically ref9$ is produc$ 9 an ord9>y smelt]4 ,! m9ts ( ! ,unit$ ,/ates are n[ all equipp$ ) electrolytic ref9+ plants to produce ! pure metal ne$$ = co9age & !y h prov$ mo/ satisfactory & economical4 ,z ! electrolytic production ( copp] is an indu/ry ( great pres5t importance1 s ! production ( iron & /eel by electricity promises to be ( ! greate/ future importance4 ,electric furnaces = mak+ /eel are n[ ma9ta9$1 & ! indu/ry has pass$ beyond an exp]im5tal condition4 ,b x has n rea*$ ! po9t :]e x is compet+ ) ! ,bessem] or ! op5 he>? process ( ! manufacture ( /eel1 :ile = ! smelt+ ( iron ores ! electric furnace has n yet be5 f\nd practical f an economic /&po9t4 ,be=e #ahhj ,sir ,william ,siem5s %[$ t an electric arc c\ld be us$ to melt iron or /eel 9 a crucible1 & he pat5t$ an electric crucible furnace :i* 0 ! fir/ attempt to use electricity 9 iron & /eel manufacture4 ,he /at$ t ! process w\ld n be too co/ly & t x _h a great future be=e x4 ,?is 0 an application ( ! int5se heat ( ! arc1 :i* supplies a high] temp]ature ?an any s\rce kn[n except t ( ! sun4 ,?is heat is us$ to melt ! metal1 9 :i* condition v>i\s impurities c be remov$ & necess>y +r$i5ts add$4 ,siem5s' furnace did n f9d ext5sive application1 l>gely on acc\nt ( ! great metallurgical developm5ts !n tak+ place 9 ! iron indu/ry & ! ?or\gh k ( metallurgical processes z c>ri$ on1 possess$ by metallurgical eng9e]s4 ,b ! idea by no means langui%$1 & 9 #ahii ,paul ,h]\lt & o!r electro-metallurgi/s 7 active 9 develop+ a practical electric furnace = iron & /eel "w4 ,! ,sw$i% eng9e]1 ,f4 ,a4 ,kjell91 0 also active & z ! result ( ! ef=ts ( ^! & o!r work]s1 by #aiji electric furnaces 7 employ$1 n only 9 ! manufacture ( special /eels ^: composition & mak+ 7 att5d$ ) special c>e1 b = rails & /ructural mat]ial4 ,!re 7 report$ to be betwe5 ?irty & =ty electric /eel plants 9 v>i\s c\ntries1 & ! outlook = ! future 0 di/9ctly bright4 ,! application ( electro- metallurgy at ?is "t 0 conf9$ to ! manufacture ( /eel1 z ! smelt+ ( iron _h n em]g$ f ! exp]im5tal /age ( its developm5t1 ?\gh ext5sive trials on a l>ge scale ( v>i\s furnaces h be5 und]tak5 9 ,europe & by ! ,canadian gov]nm5t at ,sault ,/e4 ,m>ie1 :]e ! ,h]\lt furnace1 soon to be describ$1 0 employ$4 ,electro-metallurgy ( /eel1 z 9 all utilization ( electrical p[]1 dep5ds ^u obta9+ electricity at a reasonable co/1 & !n utiliz+ ! heat ( ! arc or ( ! curr5t 9 ! mo/ practical & economical =m4 ,"o ( ! pione] furnaces = ?is purpose :i* has se5 consid]able developm5t & practical application is ! ,h]\lt furnace1 :i* is a tilt+ furnace ( ! crucible type1 ^: op]ation dep5ds ^u bo? ! heat ( ! arc & on ! heat produc$ by ! resi/ance ( ! molt5 mat]ial4 ,9 ! ,h]\lt process ! impurities ( ! molt5 iron are wa%$ out by treatm5t ) suitable slags4 ,! furnace consi/s ( a crucible 9 ! =m ( a clos$ %all[ iron tank1 ?ickly l9$ ) dolomite & magnazite brick1 ) a he>? ( cru%$ dolomite4 ,! electric curr5t ent]s ! crucible ?r\gh two massive electrodes ( solid c>bon1 #gj in*es 9 l5g? & #ad in*es 9 diamet]1 s m\nt$ t !y c be mov$ ei!r v]tically or horizontally by ! electrician 9 *>ge4 ,^! electrodes are wat]-jacket$ to r$uce ! rate ( consumption4 ,! furnace conta9s an inlet = an air bla/ & op5+s 9 its cov]+ = *>g+ ! mat]ial & = ! escape ( ! gases4 ,! actual process ( /eel-mak+ consi/s ( *>g+ ! crucible ) /eel scrap1 pig iron1 iron ore1 & lime ( ! prop] quality & 9 ! "r proportions1 plac+ ?is mat]ial on ! he>? ( ! furnace4 ,comb9$ arc & resi/ance heat+ is appli$ to raise ! *>ge to ! melt+ po9t4 ,! curr5t is ( #abj volts or ! same z t us$ 9 an ord9>y inc&esc5t light+ circuit1 b is alt]nat+ & ( #d1jjj amp]es4 ,?is is = a ?ree-ton furnace4 ,z ! mat]ial melts ! lime & silicates =m a slag :i* fuses rapidly & cov]s ! iron & /eel 9 ! crucible1 s t ! molt5 ba? is protect$ f ! action ( ! gases :i* are lib]at$ & ! oxyg5 9 ! atmosph]e4 ,! next /ep 9 ! process is to l[] ! electrodes until !y j t\* b5ea? ! surface ( ! molt5 slag s t subsequ5t heat+ is due n to ! effect ( ! arc b to ! resi/ance :i* ! ba? (f]s to ! passage ( ! curr5t4 ,air f an air bla/ is introduc$ into ! crucible to oxidize ! impurities ( ! metal1 p>ticul>ly ! sulphur & ! phosphorus :i* are c>ri$ into ! slag & ?is is remov$ by ! tilt+ ( ! furnace4 ,fre% quantities ( lime1 etc41 are add$1 & ! op]ation is repeat$ until a comp>atively pure metal rema9s1 :5 an alloy high 9 c>bon is add$ & :atev] o!r con/itu5ts are desir$ = ! f9i%$ /eel4 ,! *>ge is !n tipp$ into ! ca/+ ladle & ! "p ( ! electric furnace is f9i%$4 ,= ?ree tons ( /eel eight to t5 h\rs are requir$ 9 ! ,h]\lt crucible furnace4 ,furnaces ( an altoge!r diff]5t type are ^? employ+ an alt]nat+ curr5t1 su* z ! ,kjell9 & ,ro*l+ furnaces1 :]e ! metal to be heat$ really =ms ! second>y circuit ( a l>ge & novel =m ( trans=m] :i* 9 pr9ciple is analog\s to ! famili> trans=m] se5 to /ep d[n ! pot5tial ( alt]nat+ curr5t z = h\se light+4 ,= su* a trans=m] ! prim>y coil is =m$ ( heavy wire & ! second>y circuit is ! molt5 metal :i* is conta9$ 9 an annul> *annel4 ,! curr5t obta9$ 9 ! metal is ( consid]able int5sity1 b at l[] pot5tial ?an t 9 ! prim>y coil1 & r\ghly is equal to t ( ! prim>y multipli$ by ! numb] ( turns 9 ! coil4 ,! condition is simil> to t 9 ! ord9>y induction coil :]e ! curr5t f a batt]y at l[ pot5tial fl[s ar\nd a coil ( a few turns & is surr\nd$ by a second coil ) a l>ge numb] ( turns ( f9e wire 9 :i* curr5t ( small int5sity b ( high pot5tial is g5]at$4 ,9 ! induction furnace ! rev]se takes place & ! curr5t fl[+ 9 ! metal d]iv$ f t ( ! heavy coil 9 ! prim>y is ( great int5sity4 ,= ?is type ( furnace molt5 metal is requir$ & ! furnace is nev] entirely empti$1 s t its process is cont9u\s4 ,! temp]ature atta9$ is n z high z 9 ! arc furnace1 s t ! raw mat]ials us$ h to be ( a high degree ( purity1 & ?is has prov$ a re/riction ( ! field ( usefulness ( ?is type ( furnace 9 _m cases4 ,x1 h[ev]1 has be5 improv$ rec5tly & two r+s ( molt5 metal employ$ in/ead ( "o s t a wide c5tre tr\gh is obta9$ 9 :i* ! metal is subject$ to ord9>y resi/ance heat by direct or alt]nat+ curr5ts4 ,?is furnace p]mits ( v>i\s metallurgical op]ations & ! elim9ation ( impurities z 9 ! ,h]\lt type4 ,a ?ird type ( furnace t is meet+ ) "s ext5sive use is ! ,gir\d1 :i*1 l ! ,h]\lt furnace1 is bas$ on ! arc & resi/ance 9 pr9ciple1 b 9 its con/ruction has a numb] ( diff]5t features4 ,z ! curr5t passes horizontally f ! upp] electrodes ?r\gh ! slag & molt5 metal 9 ! furnace *amb] to ! base electrodes ( ! furnace1 x p]mits ( ! easy regulation ( ! arcs & ! use ( l[] electromotive =ce1 :ile !re is only "o arc 9 ! pa? ( ! curr5t in/ead ( two z 9 ! ,h]\lt type4 ,suffici5t quantities ( /eel h be5 made 9 electric furnaces to p]mit ( ! det]m9ation ( ! quality ( ! product z well z ! economy ( ! process4 ,x has be5 f\nd 9 ,g]many t rail /eel made 9 ! induction furnace has a mu* high] b5d+ & break+ limit ?an ord9>y ,bessem] or ,?omas rail /eel1 & 9 ,g]many 9 #aijh rails s made comm&$ a consid]ably high] price p] ton ?an ^? ( ord9>y rail /eel4 ,aft] trial ord]s _h prov$ satisfactory1 9 #aijh #e1jjj tons ( rails 7 ord]$ = ! ,italian & ,swiss gov]nm5ts at a ,g]man works1 :]e furnaces ( eight tons capacity _h be5 in/all$4 ,9 ! ,unit$ ,/ates only a few electric /eel furnaces are 9 op]ation1 & ^!1 = ! mo/ "p1 = purposes ( demon/ration & exp]im5t4 ,b 9 ,europe ! indu/ry is well e/abli%$1 & :ile at pres5t small1 is con/antly gr[+ & possesses an assur$ future4 ,9 addition to ! manufacture ( /eel1 ! application ( ! electric furnace = produc+ :at are kn[n z f]ro-alloys1 or alloys ( iron1 silicon1 *romium1 manganese1 tung/5 & vanadium1 is n[ a l>ge & important indu/ry4 ,special /eels h _! uses 9 diff]5t me*anical applications & ! advantage ( alloy+ !m ) ! r>] metals has be5 demon/rat$ = sev]al important purposes1 z = example1 ! use ( *rome /eel = armor plate1 & /eel conta9+ vanadium = p>ts ( motor c>s4 ,^! indu/ries = ! mo/ "p conta9 electric arc furnaces & h1 z _! object1 ! manufacture ( f]ro-alloys1 :i* are introduc$ into ! /eel1 x hav+ be5 f\nd advantage\s to use ! r>e metals 9 ?is =m r ?an 9 _! crude /ate4 ,!re is "o electro-metallurgical process t has made possible ! production 9 comm]cial =m & = ord9>y use ( a metal t once 0 little m ?an a *emical curiosity4 ,9 #ahhe !re 7 produc$ #c4ab tons ( alum9um1 & its value 0 r\ghly e/imat$ at ab\t #ab a p\nd4 ,by #aijh ,am]ica alone produc$ ov] #i1jjj tons valu$ at ov] #ejj1jjj1jjj1 :ile ,european manufactur]s 7 also l>ge produc]s4 ,9 #ahhh ! electrolytic manufacture ( alum9um 0 comm5c$ 9 ,am]ica & 9 ! foll[+ ye> x 0 begun 9 ,switz]l&4 ,alum9um is =m$ by ! electrolysis ( ! alum9um oxide 9 a fus$ ba? ( cryolite & fluorsp>4 ,! alum9um may be obta9$ 9 ! =m ( bauxite1 & is produc$ 9 l>ge rectangul> iron pots ) a ?ick c>bon l9+4 ,! pot itself is ! ca?ode1 :ile l>ge graphite rods susp5d$ 9 ! ba? s]ve z ! anodes4 ,aft] ! arc is =m$ & ! heat ( ! ba? rises to a suffici5t degree ! mat]ial is decompos$ & ! metal is sep>at$ out s t x c be remov$ by ladl+ or ) a siphon4 ,! application ( heat to obta9 ?is metal previ\s to ! inv5tion ( ! electric furnace c\ld only be consid]$ a laboratory problem & ! exp5se involv$ did n p]mit ( comm]cial application4 ,n[1 h[ev]1 alum9um is univ]sally available & ) ! expiration ( c]ta9 pat5ts1 ! mat]ial has sold z l[ z #be c5ts a p\nd4 ,electrolytic me?ods s]ve also = ! ref9+ ( nickel & = ! production ( lead1 & z 9 o!r fields ( metallurgy1 ^! processes are attract+ ! att5tion ( *emi/s & ( eng9e]s4 ,:ile t9 z yet has n yield$ to electrolytic or electro-!rmal me?ods ) any success1 ! removal ( t9 f t9 scraps & cutt+s has be5 c>ri$ on ) consid]able success4 ,) z9c ! electrolytic & electro-!rmal processes h n be5 able yet to compete ) ! old] metallurgical me?od ( di/illation1 b an important indu/ry is electro- galvaniz+1 :]e a solution ( z9c sulphate is deposit$ on iron & gives a protective coat+4 ,exp]im5tal me?ods ) ! use ( electricity 9 extract+ z9c f its ores are be+ te/$ at v>i\s ,european plants1 b ! matt] has n yet rea*$ a comm]cial scale4 ,"o ( ! e>lie/ notable uses ( ! electric furnace 9 a l>ge electro-*emical indu/ry 0 = ! production ( c>borundum1 a c>bide ( silicon1 :i* is rem>kably useful z an abrasive1 be+ available 9 ! manufacture ( gr9d+ /ones & o!r l purposes to replace em]y & corundum4 ,x is produc$ by ! use ( a simple electric furnace ( ! resi/ance type1 :]e coke1 s&1 & sawdu/ are heat$ to a temp]ature ( betwe5 #bjjj degrees & #cjjj degrees ,c4 ,! *emical reaction involves ! production ( c>bon monoxide1 & gives a c>bide ( silicon1 a cry/all9e solid :i* has ! excell5t abrasive prop]ties m5tion$4 ,! manufacture 0 fir/ />t$ by its inv5tor1 ,e4 ,g4 ,a*eson1 ab\t #ahia on a small scale1 & 9 ! foll[+ ye> #a1jjj p\nds ( ! mat]ial 7 produc$ at ! ,niag>a ,falls works4 ,)9 fifte5 ye>s its output _h increas$ to well ov] six million p\nds4 ,! electric furnaces at ,niag>a ,falls h suppli$ _m int]e/+ electro-*emical processes4 ,aft] mak+ a c>bide 9 ! electric furnace x 0 f\nd possible to decompose x by fur!r increas+ ! heat to a po9t :]e ! second elem5t is volatiliz$ & ! pure c>bon 9 ! =m ( artificial graphite rema9s4 ,9 m rec5t "w ! c>bide conta9+ ! silicon has be5 done away ) & ord9>y an?racite coal us$ z a *>ge f :i* ! pure graphite is obta9$4 ,?is graphite has be5 f\nd especially useful 9 electrical "w z = electrodes1 :ile a m rec5t process enables a s(t v>iety ( graphite to be obta9$ :i* becomes a competitor ( ! natural mat]ial4 ,"o ( ! mo/ int]e/+ ( ! _m electro-*emical processes is ! heat+ ( lime & coke 9 ! electric furnace s z to obta9 a product 9 ! =m ( calcium c>bide1 :i*1 on solution 9 wat]1 =ms acetyl5e gas1 a useful & valuable illum9ant4 ,?is process dates f #ahic :5 ,t4 ,l4 ,willson 9 ! ,unit$ ,/ates fir/ />t$ its manufacture on a l>ge scale1 & ! great electro*emi/1 ,h5ri ,moiss91 ab\t ! same "t indep5d5tly inv5t$ a simil> process z a result ( 8 notable "w ) ! electric furnace4 ,! process involves m]ely a trans=mation at a high temp]ature1 a portion ( ! c>bon 9 ! =m ( coke1 unit+ ) pulv]iz$ lime to give ! calcium c>bide or ,ca,c#b4 ,n[ ?is mat]ial1 :5 wat] is add$ to x1 decomposes1 & acetyl5e or ,c#b;,h#b is =m$1 :i* is a gas ( high illum9at+ value z ! c>bon sep>ates & gl[s brightly aft] be+ heat$ to inc&esc5ce 9 ! flame4 ,! electric furnace at ,niag>a ,falls has be5 able to produce /ill ano!r comb9ation 9 ! =m ( siloxicon by heat+ c>bon & silicon to a temp]ature slightly bel[ t requir$ to produce c>borundum4 ,?is product is a highly refractory mat]ial & is valuable = ! manufacture ( crucibles1 muffles1 bricks1 etc41 = "w :]e extreme temp]atures are employ$4 ,! electric furnace enables v>i\s elem5ts to be isolat$1 su*4 z silicon1 sodium1 & phosphorus1 & :5 obta9$ 9 _! pure /ate !y f9d wide application4 ,! mo/ important electro-*emical "w ( ! future is to devise "s means ( obta9+ nitrog5 f ! air4 ,x is /at$ by sci5ti/s t ! nitrog5 ( ! soil is be+ exhau/$ & t at "s future "t ! ,e>? may n be able to be> crops suffici5t = ! su/5ance ( man1 unless "s artificial means be f\nd to repl5i% ! nitrog54 ,unlimit$ supplies ( nitrog5 exi/ 9 ! air1 b to fix x ) o!r mat]ials 9 su* =m t x w be useful z a f]tiliz] has be5 "o ( ! problems to :i* ! electro-*emi/s h rec5tly devot$ mu* att5tion4 ,by ! use ( ! electric arc & pass+ air ?r\gh a furnace1 v>i\s sub/ances h be5 tri$ to take up ! nitrog5 ( ! air4 ,?us :5 calcium c>bide is heat$ & br\ght into contact ) nitrog5 "o atom ( c>bon is giv5 up & two atoms ( nitrog5 take its place1 result+ 9 ! production ( cyanamide4 ,o!r important electro-*emical processes are involv$ 9 ! electrolysis ( ! v>i\s alkal9e salts to obta9 metallic sodium & su* products z *lorates4 ,?us by ! electrolysis ( sodium *loride metallic sodium & *lor9e is obta9$4 ,f ! metallic sodium solid cau/ic soda is !n d]iv$ by a second>y reaction1 :ile ! *lor9e is comb9$ ) lime to =m *loride ( lime or blea*+ p[d]4 ,9 "s processes ! electrolysis af=ds directly an alkal9e hypo*lorite or a *lorate1 ! =m] be+ ( wide comm]cial use z a blea*+ ag5t 9 textile works & 9 ! pap] indu/ry4 ,! same process employ$ 9 ! electrolysis ( sodium salts is us$ 9 ! case ( magnesium & calcium4 ,electrolysis is also made use ( 9 ! manufacture ( *lor(orm & iod(orm1 z ! *lor9e or iod9e :i* is produc$ 9 ! electrolytic cell is all[$ to act ^u ! alcohol or acetone "u su* conditions t *lor(orm or iod(orm is produc$4 ,electro-*emi/ry plays an important "p 9 _m o!r indu/ries ^: omission f our description mu/ n be consid]$ z indicat+ any lack ( _! importance4 ,new processes con/antly are be+ discov]$ :i* may range all ! way f ! production ( artificial gems to ! :olesale production ( ! mo/ common *emicals us$ 9 ! arts4 ,9 _m bran*es ( *emical indu/ry manufactur+ processes h be5 completely *ang$1 & f ! rese>* laboratories1 :i* all l>ge progressive manufactur]s n[ ma9ta91 z well z f work]s 9 univ]sities & sci5tific s*ools1 new me?ods & discov]ies are con/antly =?com+4 ,,*apt] ,,xii4 ,,electric ,,railways4 ,! electric railway ( ,dr4 ,w]n] von ,siem5s con/ruct$ at ,b]l9 9 #ahgi 0 ! =]unn] ( a numb] ( sy/ems :i* h _h ! effect ( *ang+ mat]ially ! problems ( transportation 9 all p>ts ( ! _w4 ,! electric railway n only 0 f\nd suitable z a sub/itute = ! tramway ) its horse-drawn c>1 b f> m economical ?an ! cable c>s1 :i* 7 in/all$ to meet ! transportation problems ( l>ge cities ) heavy traffic1 or1 z 9 ! case ( c]ta9 cities on ! ,pacific slope1 :]e heavy grades made transportation a s]i\s problem4 ,fur!rmore1 ! electric railway 0 f\nd s]viceable = rural l9es :]e small /eam eng9es or dummies 7 op]at$ ) limit$ success1 & !n only "u exceptional conditions4 ,z a result1 practically e c\ntry ( ! _w :]e ! d5sity ( population & ! /ate ( civilization has w>rant$1 is trav]s$ by a network ( electric railways1 secur+ ! mo/ complete int]communication betwe5 ! v>i\s localities & h&l+ local transportation 9 a mann] impossible = a railway l9e employ+ /eam locomotives4 ,! great advance 9 electric transportation1 aside f its meet+ an economic ne$1 has be5 due to ! developm5t ( sy/ems ( g5]at+ & transmitt+ p[] economically ov] long di/ances4 ,if wat] p[] is available1 turb9es & electric g5]ators c be in/all$ & p[] produc$ & transmitt$ ov] long di/ances1 z1 = example1 f ,niag>a ,falls to ,buffalo1 or ev5 to mu* great] di/ances z 9 ! case ( p[] plants on ! ,pacific coa/ :]e m\nta9 /reams & lakes are employ$ = ?is purpose ) consid]able effici5cy4 ,a high t5sion alt]nat+ curr5t ?us c be transmitt$ ov] consid]able di/ances & !n trans=m$ into direct curr5t :i* fl[s along ! trolley wires & is utiliz$ 9 ! motors4 ,?is trans=mation is usually accompli%$ by means ( a rot>y conv]t]1 t is1 an alt]nat+ curr5t motor :i* c>ries ) x ! ess5tial elem5ts ( a direct curr5t dynamo & receiv+ ! alt]nat+ curr5t ( high pot5tial turns x out 9 ! =m ( direct curr5t at a1 l[] & /&>d pot5tial4 ,! alt]nat+ curr5t at high pot5tial c be transmitt$ ov] long di/ances ) a m9imum ( loss1 :ile ! direct curr5t at l[] pot5tial is m suitable = ! motor & c be us$ ) great] advantage1 yet its pot5tial or pressure decreases rapidly ov] long l5g?s ( l9e1 s t x is m economical to use sub-/ations to conv]t ! alt]nat+ curr5t f ! p[] plant4 ,x mu/ n be inf]r$1 h[ev]1 t all electric railways employ direct curr5t ma*9]y4 ,9 ,europe alt]nat+ curr5t has be5 us$ ) great success & also 9 ! ,unit$ ,/ates :]e a numb] ( l9es h be5 equipp$ ) ?is =m ( p[]4 ,b ! great] numb] ( in/allations employ ! direct curr5t at ab\t #ejj-fjj volts & ?is is n[ ! usual practice4 ,:e!r x w cont9ue s 9 ! future or n is p]haps an op5 "q4 ,! electric c>1 z we h se51 employs a motor :i* is ge>$ to ! axle ( ! driv+ trucks1 & ! curr5t is d]iv$ f ! trolley wire by ! famili> pole & :eel & aft] fl[+ ?r\gh ! controll] to ! motor returns by ! rail4 ,! spe$ ( ! c> is regulat$ by ! am\nt ( curr5t :i* ! motorman all[s to pass ?r\gh ! motor & ! circuits ?r\gh :i* x fl[s 9 ord] to produce diff]5t effects 9 ! magnetic attraction ( ! magnet & ! armature4 ,9 ! ord9>y electric c> = urban or suburban uses !re has be5 a con/ant increase 9 ! p[] ( ! motor & size ( ! c>s1 z x has be5 f\nd t ev5 l>ge c>s c be h&l$ ) ! requir$ facility necess>y 9 cr[d$ /reets & t !y are correspond+ly m economical to ma9ta9 & op]ate4 ,! success ( electric traction 9 l>ge cities _h be5 demon/rat$ b a few ye>s :5 x 0 appreciat$ t ! ov]head wires ( ! trolley 7 unsightly & dang]\s1 especially 9 ! case ( fire or ! break+ ( ! wires or supports4 ,accord+ly a sy/em 0 develop$ :]e ! curr5t 0 obta9$ f conductors laid 9 a conduit on insulat$ supports ?r\gh a slot 9 ! c5tre ( ! track betwe5 ! rails4 ,a pl[ susp5d$ f ! bottom ( ! c> 0 9 contact ) ! conductors :i* 7 /eel rails m\nt$ on insulat$ supports1 & ?r\gh !m ! curr5t pass$ by suitable conductors to ! controll] & motors4 ,?is sy/em f\nd an imm$iate vogue 9 ,am]ican cities1 & ?\gh m co/ly to in/all ?an ! ov]head trolley1 0 f> m satisfactory 9 its results & appe>ance4 ,9 c]ta9 cities1 ,wa%+ton1 ,d4 ,c41 = example1 ! conduit is us$ 9 ! built-up portion ( ! t[n & :5 ! suburbs are rea*$ ! pl[ is remov$ & ! motors are connect$ ) ! trolley wire by ! usual pole & :eel4 ,p]haps ! mo/ important feature ( ! electric railway 9 ! ,unit$ ,/ates has be5 ! developm5t & increase ( its effici5cy4 ,:]ev] possible traffic conditions w>rant$1 x 0 comp>atively easy to secure ! "r ( way along c\ntry highways ) little1 if any1 exp5se1 & ! con/ruction ( track & poles = su* "w 0 n a p>ticul>ly heavy outlay4 ,x 0 f\nd1 z we h se51 t ! curr5t c\ld be transmitt$ ov] consid]able di/ances s t ! opportunity 0 af=d$ to supply transportation betwe5 two t[ns at "s small di/ance :]e ! local bus9ess at ! "t ( ! con/ruction ( ! road w\ld n w>rant ! outlay4 ,?is l$ to ! sy/ems ( int]urban l9es1 small at fir/1 b z _! success 0 demon/rat$1 gradually ext5d+ & unit+ s t n only two important t[ns 7 connect$1 b ev5tually a l>ge t]ritory 0 suppli$ ) adequate transportation facilities & ev5 mail1 express1 & light freight c\ld be h&l$4 ,aga9 ! success ( su* ent]prises made x feasible = ! electric railways to =sake ! public highway & to secure a "r ( way ( _! own1 & gradually to develop express & ?r\gh s]vice1 (t5 9 direct competition ) ! local s]vice ( ! /eam railways 9 ! same t]ritory4 ,"h l>g] c>s 7 requir$ & p[] /ations ( ! mo/ mod]n & effici5t type 9 ord] to secure prop] economy ( op]ation4 ,! g5]al "* ( ma*9]y1 bo? g5]ators & motors1 0 pres]v$ ev5 = ^! long di/ance l9es1 & _! op]ation became simply an eng9e]+ problem to secure ! maximum effici5cy ) a m9imum exp5diture4 ,) ! success ( electric railways 9 cities & = suburban & int]urban s]vice naturally arose ! "q1 :y electric p[] ^: availability & economy _h be5 %[n 9 s _m circum/ances c\ld n be us$ = ! great trunk l9es :]e /eam locomotives h be5 develop$ & employ$ = s _m ye>s8 ,! "q is n entirely "o ( eng9e]+ unless z "p ( ! eng9e]+ problem we consid] ! v>i\s economic elem5ts t ent] into ! "q1 & _! inve/igation is ! important task ( ! tw5tie? c5tury eng9e]4 ,= he mu/ answ] ! "q n only is a me?od possible me*anically1 b is x pr(itable f a practical & economic /&po9t8 ,& x is "h t ! "q ( ! electrification ( trunk l9es n[ re/s4 ,! /eam locomotive has be5 develop$ to a po9t p]haps ( almo/ maximum effici5cy :]e ! greate/ spe$ & p[] h be5 secur$ t are possible on ma*9es limit$ by ! /&>d gauge ( ! track1 #d feet #h #a_/b in*es1 & ! curves :i* pres5t railway l9es & conditions ( con/ruction dem&4 ,n[1 )al1 ! /eam locomotive me*anically consid]$ is ineffici5t1 z x mu/ take ) x a l>ge weight ( fuel & wat] :i* mu/ be trans=m$ into /eam "u fix$ conditions4 ,if = example1 we h "o tra9 a day work+ ov] a c]ta9 l9e1 !re w\ld be no "q ( ! economy ( a /eam locomotive1 b ) a numb]1 we are simply ma9ta9+ isolat$ units = ! production ( p[] :i* c\ld be develop$ to f> great] advantage 9 a c5tral plant4 ,j z ! factory is m economical ?an a numb] ( work]s engag$ at _! homes1 & ! l>ge e/abli%m5t ( ! tru/ /ill m economical 9 production ?an a numb] ( factories1 s ! c5tral p[] /ation produc+ electricity :i* c be transmitt$ along a l9e & us$ z requir$ is obvi\sly m advantage\s ?an sep>ate units produc+ p[] on ! spot ) v>i\s losses inh]5t 9 small ma*9es4 ,b ev5 if ! c5tral /ation is !oretically sup]ior & m economical x does n imply t x is ei!r good policy or economy to electrify at once all ! trunk l9es ( a c\ntry su* z ! ,unit$ ,/ates & to s5d to ! scrap heap ?\s&s ( good locomotives at ! sacrifice ( millions ( doll>s & ! outlay ( millions m = electrical equipm5t4 ,9 o!r words1 unless ! f9ancial returns w w>rant x1 !re is no good & positive reason = ! electrification ( our great trans- cont95tal l9es & ev5 %ort] railroads4 ,t is ! situation to-day1 b to-morr[ is ano!r "q1 & ! f>- see+ railroad man mu/ be ready ) 8 answ] & ) 8 prep>ations4 ,to-day t]m9al s]vices 9 l>ge cities c bett] be p]=m$ by electricity1 & n only is !re economy 9 _! op]ation1 b ! abs5ce ( dirt1 smoke & noise is 9 accord ) public s5tim5t if n positively dem&$ by /atute or ord9ance4 ,suburban s]vice c be work$ mu* m economically & effectively by tra9s ( motor c>s1 & "t table & s*$ule are n limit$ by ! numb] ( available locomotives on a l9e s equipp$4 ,on m\nta9 grades1 :]e auxili>y p[] or eng9es ( extreme capacity are requir$1 electricity g5]at$ by wat] p[] f melt+ sn[ or m\nta9 lakes or /reams 9 ! vic9ity may be avail$ (4 ,"u su* conditions p[]ful motors c be us$ on m\nta9 divisions1 n only ) economy1 b ) increas$ com=t to pass5g]s1 especially :]e !re are long tunnels4 ,all ?is & m ! railway man ( to-day realizes1 & electrification to ?is ext5t has be5 accompli%$ or is 9 c\rse ( con/ruction4 ,= ea* "o ( ! s]vices m5tion$ typical in/allations c be giv5 z examples1 & to accompli% ! v>i\s ends1 !re is n only "o sy/em b sev]al sy/ems ( electrical work+1 :i* h be5 devis$ by electrical eng9e]s to meet ! difficulties4 ,to summ>ize !n1 electric work+ ( a trunk l9e results 9 increas$ economy ov] /eam locomotives by conc5tration ( ! p[] & especially by ! use ( wat] p[] :]e possible4 ,?us economy is secur$ to ! greate/ ext5t by a complete electrical s]vice & n by a mix$ s]vice ( electric & /eam locomotives4 ,electrification gives an increase 9 capacity bo? 9 ! haulage by a locomotive1 an electric locomotive be+ capable ( m "w ?an a /eam locomotive1 & 9 s*$ule & rate ( spe$1 z motor c> tra9s & electric t]m9al facilities make possible augm5t$ traffic1 & an increas$ use ( dead p>ts ( ! sy/em su* z track & roadb$4 ,!re is a great ga9 9 "t ( accel]ation & = /opp+1 & = ! ,bo/on t]m9al x 0 e/imat$ t ) electricity #ej p] c5t1 m traffic c\ld be h&l$1 z ! headway c\ld be r$uc$ f ?ree to two m9utes4 ,! mod]n t5d5cy ( electrification deals ei!r ) special conditions or :]e ! traffic is comp>atively d5se4 ,f su* a beg9n+ x is inevitable t electric work+ %\ld be ext5d$ & t is ! t5d5cy 9 all mod]n in/allations1 z = example1 at ! ,new ,york t]m9al ( ! ,new ,york ,c5tral & ,hudson ,riv] ,railroad :]e ! electric zone1 fir/ in/all$ )9 little m ?an /ation limits1 is gradually be+ ext5d$4 ,z examples ( d5sity ( traffic suitable = electrification1 yet at ! same "t possess+ problems ( _! own1 are ! great t]m9als su* z ! ,gr& ,c5tral ,/ation ( ! ,new ,york ,c5tral & ,hudson ,riv] ,railroad 9 ,new ,york ,city1 ! new ,p5nsylvania ,/ation 9 ! same city1 & t ( ! ,ill9ois ,c5tral ,/ation 9 ! city ( ,*icago4 ,n only is !re d5sity "h b ! v>i$ "* ( ! s]vice r5d]$1 su* z express1 local1 suburban1 & freight1 involves ! prompt & effici5t h&l+ ( tra9s & c>s4 ,n[1 ) suburban tra9s made up ( motor c>s1 a c]ta9 numb] ( locomotives o!rwise employ$ are releas$2 = ^! c>s c be op]at$ or %ift$ by _! own p[]4 ,su* t]m9al /ations are (t5 comb9$ ) tunnel sections1 z 9 ! case ( ! great ,p5nsylvania t]m9al1 :]e ! tunnel beg9s at ,b]g51 ,new ,j]sey1 & ext5ds "u ! ,hudson ,riv]1 b5ea? ,manhattan ,isl& & "u ! ,ea/ ,riv] to ,long ,isl& ,city4 ,x is "h t electric work+ is ess5tial = ! com=t ( pass5g]s z well z = effici5t op]ation4 ,b !re are tunnel sections n connect$ ) su* va/ t]m9als1 z 9 ! case ( ! ,/4 ,clair tunnel "u ! ,detroit ,riv]4 ,:ile ! field & future direction ( electrification is fairly well outl9$ & its future is assur$1 yet ?is future w be "o ( /eady progress r ?an "o ( sudd5 upheaval = ! economic reasons be=e /at$4 ,to-day !re are no f9al /&>ds ei!r ( sy/ems or ( motors & ! field is op5 = ! f9al evolution ( ! mo/ effici5t me?ods4 ,not)/&+ ! extraord9>y progress t has be5 made _m fur!r developm5ts are n only possible n[ b w be dem&$ ) ! progress ( ! art4 ,! great problem ( ! electric railway is ! transmission ( en]gy1 & :ile p[] may be economically g5]at$ at ! c5tral /ation1 yet1 z ,mr4 ,frank ,j4 ,sprague1 "o ( ! pione]s & =emo/ work]s 9 ! electrical eng9e]+ ( railways has s aptly said1 x is /ill at t c5tral /ation & x w suff] a c]ta9 dim9ution 9 be+ c>ri$ to ! po9t ( utilization z well z 9 be+ trans=m$ into p[] to move locomotives1 s t ^! two consid]ations lie at ! bottom ( ! electric railway & on !m dep5d ! *oice ( ! sy/em & ! design & con/ruction ( ! motor4 ,! two fundam5tal sy/ems = electric railways1 z 9 o!r p[] problems1 are ! direct curr5t & ! alt]nat+ curr5t4 ,9 ! =m] we h ! famili> trolley wire1 f$ p]haps by auxili>y conductors c>ri$ on ! support+ poles or ! und]gr\nd trolley 9 ! conduit1 or ! ?ird rail laid at ! side ( ! track4 ,all ( ^! h become /&>d practice & are op]at$ at ! usual voltage ( f #ejj to #fjj volts4 ,! curr5t on l9es ( any consid]able l5g? is alt]nat+ curr5t1 suppli$ f l>ge c5tral g5]at+ /ations & trans=m$ to direct z occasion may dem& at suitable sub-/ations4 ,rec5tly !re has be5 a t5d5cy to employ high voltage direct curr5t sy/ems :]e ! advantages ( ! use ( direct curr5t motors are comb9$ ) ! economies ( high voltage transmission1 *ief ( :i* are ! avoid+ ( p[] losses 9 transmission & ! economy 9 ! fir/ co/ ( copp]4 ,^! high voltage direct curr5t l9es 7 fir/ us$ 9 ,europe1 & dur+ ! ye> #aijg exp]im5tal l9es on ! ,vi5na railway 7 te/$4 ,,9 ,g]many & ,switz]l& te/s 7 made ( direct curr5t sy/em ( #b1jjj & #c1jjj volts & 9 #aijh !re 0 complet$ ! fir/ section ( a #a1bjj-volt direct curr5t l9e betwe5 ,indianapolis & ,l\isville1 :i* m>k$ ! fir/ use ( high t5sion direct curr5t 9 ! ,unit$ ,/ates1 & ?is 0 foll[$ by o!r successful in/allations4 ,) alt]nat+ curr5t !re c be us$ ! v>i\s =ms ( s+le phase or polyphase curr5t famili> 9 p[] "w1 b ! latt] is n[ pref]r$1 & 9 ,europe & 9 ! ,unit$ ,/ates 9 ! latt] "p ( #aijh ! numb] ( s+le phase l9es 0 e/imat$ at #bg & #bh respectively1 ) a total mileage ( #ghb & #ifg miles4 ,a trolley wire or susp5d$ conductor is us$4 ,to employ a s+le phase curr5t1 motors ( ei!r ! repulsion type or ( ! s]ies type are us$ & are ( heavi] weight ?an ! direct curr5t motors1 z !y mu/ comb9e ! functions ( a trans=m] & a motor4 ,x is = ?is reason t we (t5 see two electric locomotives at ! head ( a s+le tra9 on l9es :]e ! s+le phase sy/em is employ$1 :ile on neighbor+ l9es us+ direct curr5t1 "o locomotive ( h>dly l>g] size suffices4 ,) ! polyphase curr5t a motor ) a rotat+ field is us$1 & !y h consid]able effici5cy z reg>ds weight :5 comp>$ ) ! s+le phase & ) ! direct curr5t motor4 ,! polyphase motor1 h[ev]1 is op5 to ! objection t x does n l5d itself to regulations z well z ! direct curr5t =m1 & ) +5i\s devices involv+ ! arrangem5t ( ! magnetic field & ! comb9ation ( motors1 v>i\s runn+ spe$s c be _h4 ,! usual voltage = ^! motors is #c1jjj volts1 b 9 ! polyphase plant design$ = ! ,cascade ,tunnel #f1jjj volts are to be us$4 ,!y possess _m advantages1 especially _! ability to run at ov]load1 & consequ5tly a locomotive ) polyphase motor w run up grade )\t s]i\s loss ( spe$4 ,! s+le phase sy/em has be5 c>ri$ on on ,swiss & ,italian railroads1 notably on ! ,simplon ,tunnel & ! ,baltel9a l9es ) great success1 & ! di/ribution problems are r$uc$ to a m9imum4 ,9 ! ,unit$ ,/ates a notable in/allation has be5 on ! ,new ,york1 ,new ,hav5 ,h>t=d ,railroad1 :]e ! section betwe5 ,/am=d & ,new ,york has be5 work$ by electricity exclusively s9ce ,july #a1 #aijh4 ,"h ! s+le phase motors use direct curr5t :ile runn+ ov] ! tracks ( ! ,new ,york ,c5tral f ,woodlawn to ! ,gr& ,c5tral ,t]m9al4 ,on bo? ! ,new ,york1 ,new ,hav5 ,h>t=d & ! ,new ,york ,c5tral locomotives ! armature is =m$ directly on ! axle ( ! driv+ :eels1 s consequ5tly mu* int]e/ atta*es to ! new design adopt$ = ! ,p5nsylvania tunnels1 :]e ! armatures ( ! direct curr5t motors are connect$ ) ! driv+ :eels by connect+ rods some:at aft] ! fa%ion ( ! /eam locomotive1 & foll[+ 9 ?is respect "s successful ,european practice4 ,,app5dix4 ,,units ,,( ,,measurem5t4 7,f ,munro & ,jamieson's ,pocket-book ( ,electrical ,rules & ,tables74 ,i4 ,,fundam5tal ,,units4--,! electrical units are d]iv$ f ! foll[+ me*anical units3-- ,! ,c5timetre z a unit ( l5g?2 ,! ,gramme z a unit ( mass2 ,! ,second z a unit ( "t4 ,! ,c5timetre is equal to #j4cicg in* 9 l5g?1 & nom9ally repres5ts "o ?\s&-million? "p1 or #a_/a1jjj1jjj1jjj ( a quadrant ( ! e>?4 ,! ,gramme is equal to #ae4dcb gra9s1 & repres5ts ! mass ( a cubic c5timetre ( wat] at #d degrees ,c4 ,mass is ! quantity ( matt] 9 a body4 ,! ,second is ! "t ( "o sw+ ( a p5dulum mak+ #hf1afd4ji sw+s 9 a sid]eal day1 or #a_/hf1djj "p ( a mean sol> day4 ,,ii4 ,,d]iv$ ,,me*anical ,,units4- ,area4-,! unit ( area is ! squ>e c5timetre4 ,volume4--,! unit ( volume is ! ,,cubic ,,c5timetre4 ,,velocity is rate ( *ange ( position4 ,x involves ! idea ( direction z well z t ( magnitude4 ,,velocity is ,,uni=m :5 equal spaces are trav]s$ 9 equal int]vals ( "t ,! unit ( velocity is ! velocity ( a body :i* moves ?r\gh unit di/ance 9 unit "t1 or ! ,,velocity ,,( ,,"o ,,c5timetre ,,p] ,,second4 ,,mom5tum is ! quantity ( motion 9 a body1 & is measur$ by mass x velocity4 ,,accel]ation is ! rate ( *ange ( velocity1 :e!r t *ange take place 9 ! direction ( motion or n4 ,! unit ( accel]ation is ! accel]ation ( a body :i* und]goes unit *ange ( velocity 9 unit "t1 or an accel]ation ( "o c5timetre-p]-second p] second ,! accel]ation due to gravity is consid]ably great] ?an ?is1 = ! velocity imp>t$ by gravity to fall+ bodies 9 "o second is ab\t #iha c5timetres p] second 7or ab\t #cb4b feet p] second74 ,! value diff]s slightly 9 diff]5t latitudes4 ,at ,gre5wi* ! value ( ! accel]ation due to gravity is g#iha4ag2 at ! ,equator g#igh4a2 at ! ,nor? ,pole g#ihc4a4 ,,=ce is t :i* t5ds to alt] a body's natural /ate ( re/ or ( uni=m motion 9 a /raight l9e4 ,,=ce is measur$ by ! accel]ation :i* x imp>ts to mass--i4 e41 mass x accel]ation4 ,,! ,,unit ,,( ,,=ce1 or ,,dyne1 is t =ce :i*1 act+ = "o second on a mass ( "o gramme1 gives to x a velocity ( "o c5timetre p] second4 ,! =ce ) :i* ! e>? attracts any mass is usually call$ ! weight ( t mass1 & its value obvi\sly diff]s at diff]5t po9ts ( ! e>?'s surface ,! =ce ) :i* a body gravitates--i e1 its weight 79 dynes71 is f\nd by multiply+ its mass 79 grammes7 by ! value ( g at ! p>ticul> place :]e ! =ce is ex]t$4 ,"w is ! product ( a =ce & a di/ance ?r\gh :i* x acts4 ,! unit ( "w is ! "w done 9 ov]com+ unit =ce ?r\gh unit di/ance--i e1 9 pu%+ a body ?r\gh a di/ance ( "o c5timetre aga9/ a =* ( "o dyne4 ,x is call$ ! ,erg4 ,s9ce ! weight ( "o gramme is #a ,x #iha or #iha dynes1 ! "w ( rais+ "o gramme ?r\gh ! height ( "o c5timetre aga9/ ! =ce ( gravity is #iha ergs or g ergs4 ,"o kilogramme-metre #ajj1jjj 7g7 ergs #i #h #a ,x #ajg ergs4 ,"o foot- p\nd #ac1hbe 7g7 ergs1 #a #cef ,x #ajg ergs4 ,en]gy is t prop]ty :i*1 possess$ by a body1 gives x ! capability ( do+ "w4 ,k9etic en]gy is ! "w a body c d 9 virtue ( its motion4 ,pot5tial en]gy is ! "w a body c d 9 virtue ( its position4 ,! unit ( en]gy is ! ,erg4 ,p[] or ,activity is ! rate ( "w2 ! practical unit is call$ ! ,watt--#ajg ergs p] second4 ,a ,horse-p[] #cc1jjj ft--,ibs p] m9ute #eej ft--,ibs p] second1 b z se5 above "u ,"w1 #a ft--,ib #a #cef ,x #ajg ergs1 & "u ,p[]1 #a ,watt #ajg ergs p] sec a ,horsep[] #eej ,x #a #cef ,x #ajg ergs #gdf ,watts2 or1 ,,ec_/#gdf;,c#b,r_/#gdf;,e#b_/7gdf ,r7 ,,hp :]e ,e volts1 ,c amp]es1 & ,r ohms4 ,! ,fr5* =ce de *eval #ge kilogramme metres p] sec #gcf ,watts #edb #dh ft--lbs4 p] sec4 4#ihfc ,h4,p42 or "o ,h4,p4 #a4jache =ce de *eval4 ,,d]iv$ ,,electrical ,,units4--,!re are two sy/ems ( electrical units d]iv$ f ! fundam5tal ,c4,g4,s4 units1 "o set be+ bas$ ^u ! =ce ex]t$ betwe5 two quantities ( electricity1 & ! o!r ^u ! =ce ex]t$ betwe5 two magnetic poles4 ,! =m] set are t]m$ electro-/atic units1 ! latt] electro-magnetic units4 ,,iii4 ,,electro/atic ,,units4-- ,,unit ,,quantity ( electricity is t :i* repels an equal & simil> quantity at unit di/ance ) unit =ce 9 air4 ,,unit ,,curr5t is t :i* conveys unit quantity ( electricity along a conductor 9 a second4 ,,unit ,,electromotive ,,=ce1 or unit ,,diff]5ce ,,( ,,pot5tial exi/s betwe5 two po9ts :5 ! unit quantity ( electricity 9 pass+ f "o to ! o!r w d ! unit am\nt ( "w4 ,,unit ,,resi/ance is t ( a conductor ?r\gh :i* unit electromotive =ce betwe5 its ends c s5d a unit curr5t4 ,,unit ,,capacity is t ( a cond5s] :i* conta9s unit quantity :5 *>g$ to unit diff]5ce ( pot5tial4 ,,iv4 ,,magnetic ,,units4-- ,,unit ,,magnetic ,,pole is t :i* repels an equal & simil> pole at unit di/ance ) unit =ce 9 air4 ,,/r5g? ,,( ,,magnetic ,,field at any po9t is measur$ by ! =ce :i* w\ld act on a unit magnetic pole plac$ at t po9t4 ,,unit ,,int5sity ,,( ,,field is t int5sity ( field :i* acts on a unit pole ) unit =ce4 ,,mom5t ,,( ,a ,,magnet is ! /r5g? ( ei!r pole multipli$ by ! di/ance betwe5 ! poles4 ,,int5sity ,,( ,,magnetisation is ! magnetic mom5t ( a magnet divid$ by its volume4 ,,magnetic ,,pot5tial4--,! pot5tial at a po9t due to a magnet is ! "w t mu/ be done 9 remov+ a unit pole f t po9t to an inf9ite di/ance aga9/ ! magnetic attraction1 or 9 br++ up a unit pole f an inf9ite di/ance to t po9t aga9/ ! magnetic repulsion4 ,,unit ,,diff]5ce ,,( ,,magnetic ,,pot5tial4--,unit diff]5ce ( magnetic pot5tial exi/s betwe5 two po9ts :5 x requires ! exp5diture ( "o erg ( "w to br+ an 7,n4 or ,s47 unit magnetic pole f "o po9t to ! o!r aga9/ ! magnetic =ces4 ,v4 ,,electro-,,magnetic ,,units4-- ,,unit ,,curr5t is t :i* 9 a wire ( unit l5g?1 b5t s z to =m an arc ( a circle ( unit radius1 w\ld act ^u a unit pole at ! c5tre ( ! circle ) unit =ce4 ,,unit ,,quantity ( electricity is t :i* a unit curr5t conveys 9 unit "t4 ,,unit ,,electro-,,motive ,,=ce or ,,diff]5ce ,,( ,,pot5tial is t :i* is produc$ 9 a conductor mov+ ?r\gh a magnetic field at su* a rate z to cut "o unit l9e p] second4 ,,unit ,,resi/ance is t ( a conductor 9 :i* unit curr5t is produc$ by unit electro-motive =ce betwe5 its ends4 ,,unit ,,capacity is t ( a cond5s] :i* w be at unit diff]5ce ( pot5tial :5 *>g$ ) unit quantity4 ,electric & magnetic =ce v>ies inv]sely z ! squ>e ( ! di/ance4 ,,practical ,,units ,,( ,,electricity4 ,,resi/ance-,r4--,! ,ohm is ! resi/ance ( a column ( m]cury #ajf4c c5timetres long1 #a squ>e millimetre 9 cross-section1 weigh+ #ad4deba grammes1 & at a temp]ature ( #j degrees c5tigrade4 ,/&>ds ( wire are us$ = practical purposes4 ,! ohm is equal to a ?\s& million1 #aji1 electromagnetic or ,c5timetre-,gramme-,second 7,c4 ,g4 ,s47 units ( resi/ance4 ,! megohm is "o million ohms4 ,! microhm is "o million? ( an ohm4 ,,electromotive ,,=ce--,e4--,! ,volt is t electromotive =ce :i* ma9ta9s a curr5t ( "o amp]e 9 a conductor hav+ a resi/ance ( "o ohm4 ,! electromotive =ce ( a ,cl>k /&>d cell at a temp]ature ( #ae degrees c5tigrade is #a4dcd volts4 ,! volt is equal to a hundr$ million1 #ajh1 ,c4 ,g4 ,s4 units ( electromotive =ce4 ,,curr5t--,c4--,! ,amp]e is t curr5t :i* w decompose #j4jicbd milligramme ( wat] 7,h#b,o7 p] second or deposit #a4aah milligrammes ( silv] p] second4 ,x is equal to "o-t5? ( a ,c4 ,g4 ,s4 unit ( curr5t4 ,! milliamp]e is "o ?\s&? ( an amp]e4 ,,quantity--,q4--,! ,c\lomb is ! quantity ( electricity convey$ by an amp]e 9 a second4 ,x is equal to "o-t5? ( a ,c4 ,g4 ,s4 unit ( quantity4 ,! micro-c\lomb is "o million? ( a c\lomb4 ,,capacity--,k4--,! f>ad is t capacity ( a body1 say a ,leyd5 j> or cond5s]1 :i* a c\lomb ( electricity w *>ge to ! pot5tial ( a volt4 ,x is equal to "o ?\s&-million? ( a ,c4 ,g4 ,s4 unit ( capacity4 ,! micro-f>ad is "o million? ( a ,f>ad4 ,by ,ohm's ,law1 ,curr5t ,electromotive ,=ce_/ ,resi/ance1 or ,c ,e_/,r ,amp]e ,volt_/,ohm ,h5ce :5 we "k any two ( ^! quantities1 we c f9d ! ?ird4 ,= example1 if we "k ! electromotive =ce or diff]5ce ( pot5tial 9 volts & ! resi/ance 9 ohms ( an electric circuit1 we c easily f9d ! curr5t 9 amp]es4 ,,p[]--,p4--,! ,watt is ! p[] convey$ by a curr5t ( "o amp]e ?r\gh a conductor ^: ends diff] 9 pot5tial by "o volt1 or1 9 o!r words1 ! rate ( do+ "w :5 an amp]e passes ?r\gh an ohm4 ,x is equal to t5 million1 #ajg1 ,c4 ,g4 ,s4 units ( p[] or ergs p] second1 t is to say1 to a ,j\le p] second1 or #a_/gdf ( a horse-p[]4 ,a ,watt volt ,x amp]e1 & a ,horse-p[] ,watts_/#gdf4 ,,heat ,,or ,,"w--,w4--,! ,j\le is ! "w done or heat g5]at$ by a ,watt 9 a second1 t is1 ! "w done or heat g5]at$ 9 a second by an amp]e fl[+ ?r\gh ! resi/ance ( an ohm4 ,x is equal to t5 million1 #ajg1 ,c4 ,g4 ,s4 units ( "w or ergs4 ,assum+ ,j\le's equival5t ( heat & me*anical en]gy to be #da1fjj1jjj1 x is ! heat requir$ to raise 4#bd gramme ( wat] #a degrees c5tigrade4 ,a ,j\le ,volt x amp]e x second4 ,s9ce #a horse-p[] #eej foot p\nds ( "w p] second1 ,w #eej_/gdf ,e4 ,q4 4#gcgc ,e4 ,q4 foot p\nds4 ,,heat ,,units4 ,! ,briti% ,unit is ! am\nt ( heat requir$ to raise "o p\nd ( wat] f #fj degrees to #fa degrees ,fahr5heit4 ,x is #bea4i times great] ?an ! metric unit1 !rm or calorie1 :i* is ! am\nt ( heat requir$ to raise "o gramme ( wat] f #d degrees to #e degrees c5tigrade4 ,j\le's ,equival5t--,j4--is ! am\nt ( en]gy equival5t to a !rm or calorie1 ! metric unit ( heat4 ,x is equal to #da1fjj1jjj ergs4 ,! heat 9 !rms g5]at$ 9 a wire by a curr5t ,volt ,x amp]e ,x "t 9 seconds ,x #j4bd4 ,,light ,,units ,! ,briti% ,unit is ! light ( a sp]maceti c&le #g_/h-;in* 9 diamet]1 burn+ #abj gra9s p] h\r 7six c&les to ! p\nd74 ,!y sometimes v>y z mu* z #aj p] c5t1 f ! /&>d4 ,mr4 ,v]non ,h>c\rt's /&>d flame is equal to an av]age /&>d c&le4 ,! ,fr5* ,unit is ! light ( a ,c>cel lamp1 & is equival5t to #i ,t_/,z ,briti% units4