,transcrib]'s ,notes ,inconsi/5t spell+s 7e4g4 depol>is] depol>iz]7 & hyph5ation 7e4g4 guttap]*a gutta-p]*a7 are reta9$ z 9 ! orig9al text4 ,m9or punctuation errors are correct$ )\t comm5t4 ,*anges :i* h be5 made to ! text 79 ! case ( typographical errors7 are li/$ at ! end ( ! book4 ,?is ,pla9 ,text v]sion uses symbols f ! ,,ascii "* set only4 ,italic typeface is %[n ) surr\nd+ und]scores2 small capital typeface is %[n by ,,all ,,caps2 sup]script typeface is %[n by a prec$+ c>et 774 ,subscripts 9 *emical =mulae are %[n ) und]scores & braces1 e4g4 ,h#b,,s#d4 ,! foll[+ are us$ to repres5t o!r acc5t$ & special symbols3 3,a1 3,o1 3,u ,a-umlaut1 ,o-umlaut1 ,u-umlaut a a-curcumflex ,,ae1 ae upp] & l[] case ae-ligature 'e1 e'1 e e-acute1 e-grave1 e-circumflex oe oe-ligature batt]y v]tical l9es 7?ick & ?97 box op5 up #c sides ( rectangul> 7op5 side up7 box op5 d[n #c sides ( rectangul> 7op5 side d[n7 deg4 degree symbol ,lambda sans-s]if capital ,lambda rotat$ ,s ,s-l symbol rotat$ #ij deg4 ,l1 ,u1 ,v sans-s]if lett] %apes ,s section symbol 99 99 99 99 99 ,,electric ,,bells ,,& ,,all ,,ab\t ,,!m4 ,a ,practical ,book = ,practical ,m54 ,,) ,,m ,,?an #ajj ,,illu/rations4 ,,by ,s4 ,r4 ,,bottone1 ,,c]tificat$ ,,by ,,s\? ,,k5s+ton 7,,late ,,( ,,! ,,collegio ,,del ,,c>m9e1 ,,tur91 ,,& ,,( ,,! ,,i/ituto ,,bell9o1 ,,nov>a72 ,au?or ( ,! ,dynamo1 ,electrical ,in/rum5ts = ,amateurs1 c4 ,,london3 ,,:ittak] ,,co41 ,,pat]no/] ,,squ>e1 ,e4,c4 #ahhi4 7,all rights res]v$47 ,,preface4 ,s rapidly has ! use ( electric bells & simili> signall+ appliances ext5d$1 9 mod]n h\ses1 (fices1 hotels1 lifts1 & %ips1 t e bell-fitt] mu/ h felt ! ne$ ( accurate k ( ! mann] 9 :i* ^! in/rum5ts act & are made4 ,9 ! foll[+ pages ! au?or has attempt$ to supply ?is ne$1 by giv+ full details z to ! con/ruction ( batt]ies1 bells1 pu%es1 detectors1 etc41 ! mode ( wir+1 te/+1 connect+ up1 localiz+ faults1 &1 9 po9t ( fact1 by direct+ c>eful att5tion to e case t c pres5t itself to ! electric-bell fitt]4 ,,c>%alton1 ,,surrey1 ,novemb]1 #ahhh4 ,,cont5ts4 ,,*ap4 ,,page ,i4 ,,prelim9>y ,,consid]ations #a ,,ii4 ,,on ,,! ,,*oice ,,( ,,batt]ies ,,= ,,electric ,,bell ,,"w #ah ,,iii4 ,,on ,,electric ,,bells ,,& ,,o!r ,,signall+ ,,appliances #ei ,,iv4 ,,on ,,contacts1 ,,pu%es1 ,,swit*es1 ,,keys1 ,,al>ms1 ,,& ,,relays #aji ,v4 ,,on ,,wir+1 ,,connect+ ,,up1 ,,& ,,localis+ ,,faults #add ,,li/ ,,( ,,illu/rations4 ,,fig4 ,,page #a4 ,direction ( curr5t 9 cell #i #b4 out ( cell #aj #c4 ,b> & horse-%oe magnets #ad #d4 ,! ,dynamo #af #e4 ,smee cell #bh #f4 ,daniell cell #cj #g4 ,gravity cell #cb #h4 ,leclan*'e cell & p>ts #cd #i4 ,agglom]ate cell #dj #aj4 ,judson cell #db #aa4 ,batt]y 9 box #dc #ab4 ,g5t cell #dd #ac4 ,bi*romate cell #dh #ad4 ,full] cell #ej #ae4 ,cells c\pl$ 9 s]ies #ed #af4 ,p>allel #eg #ag4 ,outl9e ( electric bell #fa #ah4 ,frame ( bell #fb #ai4 ,e-%ap$ frame #fc #bj4 ,electro-magnet1 old =m #fd #bj;,a4 mod]n =m #fe #ba4 ,magnet frame #ff #ba;,a4 ,w9d] #gb #bb4 ,mode ( jo9+ electromagnet wires #gc #bc4 ,armature spr+ #gd #bd4 ,ano!r =m #gd #be4 ,plat9um tipp$ screw #ge #bf4 spr+ #gf #bg4 ,b9d+ screws #gg #bh4 ,bell or gong #gh #bi4 ,pill> & nuts #gh #cj4 ,wa%]s #gh #ca4 ,trembl+ bell #ha #cb4 ,bell action enclos$ 9 case #hh #cc4 ,ord9>y trembl+ bells #ij #cd4 ,s+le /roke bell #ia #ce4 ,cont9u\s r+ bell #id #cf4 ,release action #ie #cg4 ,cont9u\s r++ ) relay #if #ch4 ,cont9u\s r++ action ) indicator #ig #ci4 ,relay & det5t lev] = indicator #ig #dj4 ,call['s atta*m5t #ii #dj;,a4 ,?orpe's arrangem5t #aja #da4 ,j5s5 bell1 section #ajb #db4 ext]ior #ajd #dc;,a4 ,circul> bell #ajf #dc;,b4 ,m9+ bell #ajf #dd4 ,electric trumpet 7,b9swang]'s7 #ajg #de4 ,v>i\s =ms ( pu%es #aaj #df4 ,pressel #aaa #dg4 ,pull #aab #dh4 ,b$room pull #aac #di;,a4 ,ano!r =m #aad #di;,b4 ,floor contact1 ball =m #aad #ej4 ,burgl> al>m #aae #ea4 ,ano!r =m #aae #eb4 ,floor contact #aae #ec4 ,door contact #aaf #ed4 ,sa% contact #aag #ee4 ,%op door contact #aag #ef;,a4 ,clos$ circuit sy/em1 s+le #aai #ef;,b4 ,clos$ circuit sy/em1 d\ble #aai #eg4 ,modifi$ gravity1 ,daniell #abj #eh4 ,contact = clos$ circuit #aba #ei4 ,!rmomet] al>m #abb #fj4 ,fire al>m #abc #fa;,a4 ,ano!r =m #abc #fa;,b4 9 action #abc #fb4 ,b9swang]'s wat* al>m contact #abe #fc4 ,wat*man's electric tell-tale clock #abf #fd4 ,lev] swit*1 two-way #abh #fe4 ,morse key1 d\ble contact #acc #ff4 ,relay #acd #fg4 ,indicator1 drop #acg #fh4 ,semaphore #ach #fi4 ,fall back #aci #gj4 ,p5dulum #adj #ga4 ,c\pl$ up #adb #gb4 ,g5t's tripol> #adc #gc4 ,sold]+ iron & wires #adh #gd4 ,pu%1 int]ior ( #aea #ge4 ,bell1 batt]y & pu% #aei #gf4 ,& e>? return #afj #gg4 & two pu%es #afa #gh4 two pu%es & "o pull #afa #gi4 ,two bells 9 p>allel #afb #hj4 ,ano!r mode #afb #ha4 ) two-way swit* #afc #hb4 ,s]ies c\pl] #afc #hc4 ,bell ) local batt]y & relay #afd #hd4 ,cont9u\s r++ bell ) wire return #afe #he4 ,bells ) ,morse keys = signall+ #afe #hf4 ,bells ) d\ble contact pu%es = signall+ #aff #hg4 ,bells ) d\ble contact ) "o batt]y only #afg #hh4 ,two-way signall+ ) "o batt]y only #afh #hi4 ,complete in/allation ( bells1 batt]ies1 pu%es1 etc4 #afi #ij4 ,mode ( gett+ out plan or design #agj #ia4 ,lift fitt$ ) bells #agc #ib4 ,magneto bell3 g5]ator #agd #ic4 ,receiv] #age #id4 ,comb9$ #agf #ie4 ,detector or galvanomet] #agf ,,electric ,,bells4 ,,*apt] ,i4 ,,prelim9>y ,,consid]ations4 ,s #a4 ,,electricity4--,! prim>y cause ( all ! effects :i* we are ab\t to consid] resides 9 a =ce kn[n z electricity1 f ! ,greek "n ( amb] 7electron71 ?is be+ ! body 9 :i* ! manife/ations 7 fir/ obs]v$4 ,! anci5ts 7 acqua9t$ ) a few deta*$ facts1 su* z ! attractive p[] acquir$ by amb] aft] friction2 ! b5umb+ %ocks giv5 by ! torp$o2 ! aurora borealis2 ! lightn+ fla%2 & ! sp>ks or /reams ( light :i*1 "u c]ta9 conditions1 are se5 to issue f ! human body4 ,?ales1 a ,grecian philosoph]1 :o fl\ri%$ ab\t #fjj ye>s ,b4,c41 obs]v$ ! =m] ( ^! facts1 b ne>ly tw5ty c5turies elaps$ be=e x 0 suspect$ t any connection exi/$ betwe5 ^! ph5om5a4 ,s #b4 ,accord+ to ! pres5t /ate ( our k1 x w\ld appe> t electricity is a mode ( motion 9 ! con/itu5t p>ticles 7or atoms7 ( bodies v simil> to1 if n id5tical )1 heat & light4 ,^!1 l s\nd1 are kn[n to be dep5d5t on undulatory motion2 b1 :il/ s\nd is elicit$ by ! vibration ( a body z a :ole1 electricity appe>s to dep5d1 9 its manife/ations1 ^u "s motion 7:e!r rot>y1 oscillatory1 or undulatory1 x is n kn[n7 ( ! atoms !mselves4 ,h[ev] ?is be1 x is c]ta9 t :atev] t5ds to set up molecul> motion1 t5ds also to call =? a display ( electricity4 ,h5ce we h sev]al practical means at our disposal = evok+ electrical effects4 ,^! may be conv5i5tly divid$ into ?ree classes1 viz43--#a/1 me*anical2 #bnd1 *emical2 #crd1 *anges ( temp]ature4 ,among ! me*anical may be rang$ friction1 p]cussion1 vibration1 trituration1 cleavage1 etc4 ,among ! *emical we note ! action ( acids & alkalies ^u metals4 ,e *emical action is accompani$ by electrical effects2 b n all su* actions are conv5i5t s\rces ( electricity4 ,*anges ( temp]ature1 :e!r sudd5 or gradual1 call =? electricity1 b ! displays are g5]ally m /rik+ 9 ! =m] ?an 9 ! latt] case1 ow+ to ! accumulat$ effect be+ pres5t$ 9 a %ort] "t4 ,s #c4 ,we may n[ proce$ to /udy a few ( ^! me?ods ( evok+ electricity1 s z to famili>ise ourselves ) ! lead+ prop]ties4 ,if we rub any res9\s sub/ance 7su* z amb]1 copal1 res91 seal+-wax1 ebonite1 etc47 ) a piece ( w>m1 dry flannel1 we %all f9d t x acquires ! p[] ( attract+ light bodies1 su* z small pieces ( pap]1 /raw1 pi?1 etc4 ,aft] rema9+ 9 contact ) ! rubb$ 7or electrifi$7 sub/ance = a %ort "t1 ! pap]1 etc41 w fly (f z if repell$2 & ?is app>5t repulsion w be m evid5t & m quickly produc$ if ! exp]im5t be p]=m$ ov] a metal tray4 ,if a small pi?-ball1 ! size ( a pea1 be susp5d$ f ! ceil+ by a piece ( f9e cotton1 previ\sly damp$ & !n approa*$ by an ebonite comb :i* has be5 briskly rubb$1 x w be vigor\sly attract$1 & nev] repell$2 b if = ! cotton !re be sub/itut$ a ?read or fibre ( v f9e dry silk1 ! pi?-ball w be fir/ attract$ & !n repell$4 ,?is is ow+ to ! fact t ! damp cotton all[s ! electricity to escape along x3 id e/1 damp cotton is a ,,conductor ( electricity1 :ile silk does n p]mit its dissipation2 or1 9 o!r words1 silk is a ,,non-,,conductor4 ,all bodies ) :i* we are acqua9t$ are f\nd1 on trial1 to fall "u "o or o!r ( ! two heads--viz41 conductors & non-conductors4 ,nature kn[s no h>d l9es1 s t we f9d t ev5 ! wor/ conductors w p]mit ! escape ( "s electricity1 :ile ! v be/ conductors oppose a measurable resi/ance to its passage4 ,betwe5 ! limits ( good conductors1 on ! "o h&1 & non-conductors 7or insulators7 on ! o!r1 we h bodies possess+ v>y+ degrees ( conductivity4 ,s #d4 ,z a k ( :i* bodies are1 & :i* are n1 conductors ( electricity is absolutely ess5tial to e "o aspir+ to apply electricity to any practical purpose1 ! foll[+ table is subjo9$1 giv+ ! names ( ! common] bodies1 beg9n+ ) ^? :i* mo/ readily transmit electricity1 or are good conductors1 & end+ ) ^? :i* oppose ! highe/ resi/ance to its passage1 or are insulators1 or non-conductors3-- ,s #e4 ,,table ,,( ,,conductors ,,& ,,insulators4 ---------------------------------------- ---------------------------- ,quality4 ,"n ( ,sub/ance4 ,relative ,resi/ance4 ---------------------------------------- ---------------------------- ,good ,silv]1 anneal$ #a4 ,conductors ,copp]1 anneal$ #a4jfc ,silv]1 h>d drawn #a4jhf ,copp]1 h>d drawn #a4jhf ,gold1 anneal$ #a4cfi ,gold1 h>d drawn #a4cic ,alum9ium1 anneal$ #a4ice ,z9c1 press$ #c4gda ,brass 7v>iable7 #e4jjj ,plat9um1 anneal$ #f4jbb ,iron #f4dej ,/eel1 s(t #f4ejj ,gold & silv] alloy1 #b to #a #g4bbh ,nickel1 anneal$ #h4bhe ,t91 press$ #h4ghd ,lead1 press$ #ac4jej ,g]man silv] 7v>iable7 #ac4ibj ,plat9um-silv] alloy1 #a to #b #af4baj ,/eel1 h>d #be4jjj ,antimony1 press$ #bc4fjj ,m]cury #fb4gcj ,bismu? #hg4bcj ,graphite #ade4jjj ,nitric ,acid #igfjjj4jjj ,imp]fect ,hydro*loric acid #a ,conductors ,sulphuric acid #ajcbjbj4jjj ,solutions ( metallic salts v>ies ) /r5g? ,metallic sulphides #a ,di/ill$ wat] #a #fgedbjh4jjj ,inf]ior ,metallic salts1 solid #a ,conductors4 ,l95 ,cotton & o!r =ms ( #a ,hemp cellulose ,pap] ,alcohol #a ,e!r #a ,dry ,wood #a ,dry ,ice #a ,metallic ,oxides #a ,non-conductors1 ,ice1 at #be c4 #a or ,fats & oils #a ,insulators4 ,ca\t*\c #ajjjjjjjjjjjj4 ,guttap]*a #ajjjjjjjjjjjj4 ,dry air1 gases1 & vap\rs #a ,wool #a ,ebonite #acjjjjjjjjjjj4 ,diamond #a ,silk #a ,glass #a ,wax #a ,sulphur #a ,res9 #a ,amb] #a ,%ellac #a ,p>aff9 #aejjjjjjjjjjj4 ---------------------------------------- ---------------------------- ,footnote #a3 ,^! h n be5 accurately measur$4 ,! figures giv5 z indicat+ ! relative resi/ance ( ! above bodies to ! passage ( electricity mu/ be tak5 z approximate only1 s9ce ! conductivity ( all ^! bodies v>ies v l>gely ) _! purity1 & ) ! temp]ature4 ,metals become worse conductors :5 heat$2 liquids & non-metals1 on ! contr>y1 become bett] conductors4 ,x mu/ be borne 9 m9d t dry air is "o ( ! be/ insulators1 or wor/ conductors1 ) :i* we are acqua9t$2 :ile damp air1 on ! contr>y1 ow+ to ! facility ) :i* x deposits wat] on ! surface ( bodies1 is highly conducive to ! escape ( electricity4 ,s #f4 ,if ! exp]im5t describ$ at ,s #c be repeat$1 sub/itut+ a glass rod = ! ebonite comb1 x w be f\nd t ! pi?-ball w be fir/ attract$ & !n repell$1 z 9 ! case ) ! ebonite2 & if ( two simil> pi?-balls1 ea* susp5d$ by a fibre ( silk1 "o be treat$ ) ! excit$ ebonite & ! o!r ) ! glass rod1 until repulsion occurs1 & !n approa*$ to ea* o!r1 ! two balls w be f\nd to attract ea* o!r4 ,?is proves t ! electrical condition ( ! excit$ ebonite & ( ! excit$ glass mu/ be diff]5t2 = _h x be5 ! same1 ! two balls w\ld h repell$ "o ano!r4 ,f>!r1 x w be f\nd t ! rubb] ) :i* ! ebonite or ! glass rod h be5 excit$ has also acquir$ electrical prop]ties1 attract+ ! pi?-ball1 previ\sly repell$ by ! rod4 ,f ?is we may ga!r t :5 "o body act+ on ano!r1 ei!r me*anically or *emically1 sets up an electrical condition 9 "o ( ! two bodies1 a simil> electrical condition1 b 9 ! opposite s5se1 is produc$ 9 ! o!r3 9 po9t ( fact1 t x is impossible to excite any "o body )\t excit+ a correspond+ b opposite /ate 9 ! o!r4 7,we may take1 z a r\gh me*anical illu/ration ( ?is1 ! effect :i* is produc$ on ! pile ( two pieces ( plu% or fur1 on be+ drawn across "o ano!r 9 opposite directions4 ,on exam9ation we %all f9d t bo? ! piles h be5 laid d[n1 ! upp] 9 ! "o direction1 ! l[] 9 ! o!r47 ,= a long "t ^! two electrical /ates 7 held to dep5d ^u two di/9ct electricities1 :i* 7 call$ respectively vitre\s & res9\s1 to indicate ! nature ( ! bodies f :i* !y 7 d]iv$4 ,lat] on 7:5 x 0 f\nd t ! !ory ( a s+le electricity c\ld be made to acc\nt = all ! ph5om5a1 provid$ x 0 grant$ t "s electrifi$ bodies acquir$ m1 :ile o!rs acquir$ less ?an _! natural %>e ( electricity71 ! two /ates 7 kn[n z positive & negative2 & ^! names are /ill reta9$1 al?\gh x is pretty g5]ally conc$$ t electricity is n an entity 9 itself1 b simply a mode ( motion4 ,s #g4 ,x is usual1 9 treatises on electricity1 to give a long li/ ( ! sub/ances :i* acquire a positive or a negative condition :5 rubb$ aga9/ "o ano!r4 ,su* a table is ( v little use1 s9ce ! slighte/ modification 9 physical condition w influ5ce v consid]ably ! result4 ,= example3 if two simil> %eets ( glass be rubb$ ov] "o ano!r1 no *ange 9 electrical condition is produc$2 b if "o be r\gh$ :ile ! o!r is left poli%$1 ?is latt] becomes positively1 :ile ! =m] becomes negatively1 electrifi$4 ,s1 also1 if "o %eet ( glass be w>m$1 :ile ! o!r be left cold1 ! cold] becomes positively1 & ! latt] negatively1 excit$4 ,z a g5]al law1 t body1 ! p>ticles ( :i* are m easily displac$1 becomes negatively electrifi$4 ,s #h4 ,z1 h[ev]1 ! electricity set up by friction has n hi!rto f\nd any practical application 9 electric bell-r++ or signall+1 we ne$ n to g m deeply into ?is portion ( ! subject1 b pass at once to ! electricity elicit$ by ! action ( acids1 or _! salts1 on metals4 ,"h1 z might be expect$ f ! law enunciat$ above1 ! metal m act$ on by ! acid becomes negatively electrifi$1 :ile ! "o less act$ on becomes positive4#b ,! foll[+ table1 copi$ f ,ganot1 gives an idea ( ! electrical condition :i* ! common] metals & graphite assume :5 two ( !m are imm]s$ at ! same "t 9 dilute acid3-- v ,z9c4 v ,cadmium4 ,t94 ,lead4 ,iron4 ,! portion ,nickel4 ,! portion out imm]s$ 9 ! ,bismu?4 ( ! acid fluid acid fluid4 ,antimony4 ,copp]4 ,silv]4 ,gold4 ,plat9um4 v ,graphite4 ,footnote #b3 ,?is ref]s1 ( c\rse1 to ^? portions ( ! metals :i* are out ( ! acid4 ,= reasons :i* w be expla9$ f>!r on1 ! condition ( ! metals 9 ! acid is j ! opposite to ?is4 ,! mean+ ( ! above table is1 t if we te/ ! electrical condition ( any two ( its memb]s :5 imm]s$ 9 an acid fluid1 we %all f9d t ! ones at ! head ( ! li/ are positive to ^? bel[ !m1 b negative to ^? above !m1 if ! te/ h ref]5ce to ! condition ( ! p>ts )9 ! fluid4 ,on ! contr>y1 we %all f9d t any memb] ( ! li/ w be f\nd to be negative to any "o bel[ x1 or positive to any above x1 if te/$ f ! portion ,,n imm]s$ 9 ! acid fluid4 ,illu/ration3 ,fig4 #a4 ,illu/ration3 ,fig4 #b4 ,s #i4 ,a v simple exp]im5t w make ?is q cle>4 ,two /rips1 "o ( copp] & ! o!r ( z9c1 #a wide by #d long1 h a #ab l5g? ( copp] wire sold]$ to "o extremity ( ea*4 ,a small flat piece ( cork1 ab\t #a long by #a squ>e section1 is plac$ betwe5 ! two plates1 at ! end :]e ! wires h be5 sold]$1 ?is portion be+ !n la%$ toge!r by a few turns ( wax$ /r+4 7,! plates %\ld n t\* ea* o!r at any po9t47 ,if ?is comb9ation 7:i* con/itutes a v primitive galvanic c\ple7 be imm]s$ 9 a tumbl] ?ree-p>ts fill$ ) wat]1 r5d]$ j s\r by ! addition ( a few drops ( sulphuric or hydro*loric acid1 we %all get a manife/ation ( electrical effects4 ,if a delicately pois$ magnetic ne$le be all[$ to take up its natural position ( nor? & s\?1 & !n ! wires proce$+ f ! two metal /rips twi/$ 9 contact1 s z to be p>allel to & ov] ! ne$le1 z %[n 9 ,fig4 #a1 ! ne$le w be impell$ out ( its normal position1 & be deflect$ m or less out ( ! l9e ( ! wire4 ,if ! ne$le be aga9 all[$ to come to re/ ,n4 & ,s4 7! batt]y or c\ple hav+ be5 remov$71 & !n ! tumbl] be held close ov] ! ne$le1 z 9 ,fig4 #b1 s t ! ne$le po9ts f ! copp] to ! z9c /rip1 ! ne$le w be aga9 impell$ or deflect$ out ( its natural position1 b 9 ?is case 9 ! opposite direction4 ,s #aj4 ,x is a well-kn[n fact t if a wire1 or any o!r conductor1 along :i* ! electric undulation 7or1 z is usually said1 ! electric curr5t7 is pass+1 be br\ght ov] & p>allel to a susp5d$ magnetic ne$le1 po9t+ nor? & s\?1 ! ne$le is imm$iately deflect$ f ?is nor? & s\? position1 & assumes a new direction1 m or less ea/ & we/1 accord+ to ! amplitude ( ! curr5t & ! ne>ness ( ! conductor to ! ne$le4 ,moreov]1 ! direction 9 :i* ! nor? pole ( ! ne$le is impell$ is f\nd to be dep5d5t ^u ! direction 9 :i* ! electric waves 7or curr5t7 ent] ! conduct+ body or wire4 ,! law :i* regulates ! direction ( ^! deflections1 & :i* is kn[n1 f ! "n ( its orig9ator1 z ,ampe're's law1 is briefly z foll[s3-- ,s #aa4 ,if a curr5t be caus$ to fl[ ov] & p>allel to a freely susp5d$ magnetic ne$le1 previ\sly po9t+ nor? & s\?1 ! nor? pole w be impell$ to ! ,,left ( ! ent]+ curr5t4 ,if1 on ! contr>y1 ! wire1 or conductor1 be plac$ bel[ ! ne$le1 ! deflection w1 "u simil> circum/ances1 be 9 ! opposite direction1 viz43 ! nor? pole w be impell$ to ! ,,"r ( ! ent]+ curr5t4 ,9 bo? ^! cases ! obs]v] is suppos$ to be look+ along ! ne$le1 ) its ,n4 seek+ pole po9t+ at him4 ,s #ab4 ,f a consid]ation ( ! above law1 9 connection ) ! exp]im5ts p]=m$ at ,s #i1 x w be evid5t t inside ! tumbl] ! z9c is positive to ! copp] /rip2 :ile1 view$ f ! outside conductor1 ! copp] is positive to ! z9c /rip4#c ,footnote #c3 ,f "s rec5t inve/igations1 x w\ld appe> t :at we usually t]m ! negative is really ! po9t at :i* ! undulation takes its rise4 ,s #ac4 ,a prop]ty ( curr5t electricity1 :i* is ! fundam5tal basis ( electric bell-r++1 is t ( conf]r+ ^u iron & /eel ! p[] ( attract+ iron & simil> bodies1 or1 z x is usually said1 ( r5d]+ iron magnetic4 ,if a s(t iron rod1 say ab\t #d long by #a_/b diamet]1 be w\nd ev5ly f end to end ) ?ree or f\r lay]s ( cotton-cov]$ copp] wire1 say ,no4 #bj gauge1 & plac$ 9 proximity to a few iron nails1 etc41 no attractive p[] w be ev9c$2 b let ! two free ends ( ! wire be plac$ 9 metallic contact ) ! wires lead+ f ! simple batt]y describ$ at ,s #i1 & x w be f\nd t ! iron has become p[]fully magnetic1 capable ( su/a9+ sev]al ounces weight ( iron & /eel1 s long z ! wires f ! batt]y are 9 contact ) ! wire encircl+ ! iron2 or1 9 o!r words1 ! s(t iron is a magnet1 s long z an electric curr5t fl[s r\nd x4 ,if contact betwe5 ! batt]y wires & ! coil$ wires be brok51 ! iron loses all magnetic p[]1 & ! nails1 etc41 drop (f imm$iately4 ,a piece ( s(t iron ?us coil$ ) cov]$ or insulat$ wire1 no matt] :at its %ape may be1 is t]m$ an electro-magnet4 ,_! *ief peculi>ities1 z comp>$ ) ! ord9>y p]man5t /eel magnets or lode/ones1 are1 fir/1 _! great attractive & su/a9+ p[]2 secondly1 ! rapidity1 nay1 in/antaneity1 ) :i* !y lose all attractive =ce on ! cessation ( ! electric fl[ ar\nd !m4 ,x is on ^! two prop]ties t _! usefulness 9 bell-r++ dep5ds4 ,s #ad4 ,if1 in/ead ( us+ a s(t iron b> 9 ! above exp]im5t1 we _h sub/itut$ "o ( h>d iron1 or /eel1 we %\ld h f\nd two rem>kable diff]5ces 9 ! results4 ,9 ! fir/ place1 ! b> w\ld h be5 f\nd to reta9 its magnetism in/ead ( los+ x imm$iately on contact ) ! batt]y be+ brok52 &1 9 ! second place1 ! attractive p[] elicit$ w\ld h be5 mu* less ?an 9 ! case ( s(t iron4 ,x is !re=e ( ! highe/ importance1 9 all cases :]e rapid & p[]ful magnetisation is desir$1 t ! cores ( ! electro-magnets %\ld be ( ! v s(te/ iron4 ,long anneal+ & gradual cool+ conduce greatly to ! s(tness ( iron4 ,illu/ration3 ,fig4 #c4 ,,magnets1 %[+ ,l9es ( ,=ce4 ,s #ae4 ,!re is yet ano!r s\rce ( electricity :i* mu/ be notic$ "h1 z x has already f\nd application 9 "s =ms ( electric bells & signall+1 & :i* promises to ent] into m ext5d$ use4 ,if we spr9kle "s iron fil+s ov] a b> magnet1 or a horse-%oe magnet1 we %all f9d t ! fil+s arrange !mselves 9 a def9ite position along ! l9es ( greate/ attractive =ce2 or1 z sci5ti/s usually say1 ! iron fil+s arrange !mselves 9 ! direction ( ! l9es ( =ce4 ,! entire space act$ on by ! magnet is usually kn[n z its field4 ,fig4 #c gives an idea ( ! di/ribution ( ! iron fil+s1 & also ( ! g5]al direction ( ! l9es ( =ce4 ,x is f\nd t if a body be mov$ be=e ! poles ( a magnet 9 su* a direction z to cut ! l9es ( =ce1 electricity is excit$ 9 t body1 & also ar\nd ! magnet4 ,! ord9>y magneto-electric ma*9es ( ! %ops are illu/rations ( ! application ( ?is prop]ty ( magnets4 ,!y consi/ ess5tially 9 a horse-%oe magnet1 9 front ( :i* is caus$ to rotate1 by means ( appropriate ge>+1 or :eel & b&1 an iron bobb91 or pair ( bobb9s1 coil$ ) wire4 ,! ends ( ! wire on ! bobb9s are br\ght out & fa/5$ to insulat$ portions ( ! sp9dle1 & revolve ) x4 ,two spr+s press aga9/ ! sp9dle1 & pick up ! curr5t g5]at$ by ! motion ( ! iron bobb9s be=e ! poles ( ! magnet4 ,x is q indiff]5t :e!r we use p]man5t /eel magnets or electro-magnets to produce ?is effect4 ,if we use ! latt]1 & m especially if we cause a portion ( ! curr5t set up to circulate r\nd ! electro-magnet to ma9ta9 its p[]1 we designate ! app>atus by ! "n ( ,,dynamo4 ,illu/ration3 ,fig4 #d4 ,,typical ,,dynamo1 %[+ ess5tial portions4 ,s #af4 ,our space w n p]mit ( a v ext5d$ description ( ! dynamo1 b ! foll[+ brief outl9e ( its con/ructive details w be f\nd useful to ! /ud5t4 ,a mass ( s(t iron 7%ape immat]ial7 is w\nd ) _m turns ( insulat$ copp] wire1 9 su* a mann] t1 7 an electrical curr5t s5t along ! wire1 ! mass ( iron w\ld become /rongly nor? at "o extremity1 & s\? at ! o!r4 ,z prolongations ( ! electro-magnet ?us produc$ are affix$ two masses ( iron fac+ "o ano!r1 & s fa%ion$ or bor$ out z to all[ a r+1 or cyl9d] ( s(t iron1 to rotate betwe5 !m4 ,?is cyl9d]1 or r+ ( iron1 is also w\nd ) insulat$ wire1 two or m ends ( :i* are br\ght out 9 a l9e ) ! sp9dle on :i* x rotates1 & fa/5$ d[n to z _m insulat$ sections ( brass cyl9d] plac$ ar\nd ! circumf]5ce ( ! sp9dle4 ,two metallic spr+s1 connect$ to b9d+ screws :i* =m ! t]m9als ( ! ma*9e1 s]ve to collect ! electrical wave set up by ! rotation ( ! coil$ cyl9d] 7or armature7 be=e ! poles ( ! electro-magnet4 ,! annex$ cut 7,fig4 #d7 w assi/ ! /ud5t 9 gett+ a cle> idea ( ! ess5tial portions 9 a dynamo3--,e is ! mass ( wr\ght iron w\nd ) insulat$ wire1 & kn[n z ! field-magnet4 ,n & ,s are ca/-iron prolongations ( ! same1 & are usually bolt$ to ! field-magnet4 ,:5 curr5t is pass+ ^! become p[]fully magnetic4 ,a is ! rotat+ iron r+1 or cyl9d]1 kn[n z ! armature1 :i* is also w\nd ) insulat$ wire1 ,b1 ! ends ( :i* are br\ght out & connect$ to ! insulat$ brass segm5ts kn[n z ! commutator1 ,c4 ,^u ?is commutator press ! two spr+s ,d & ,d'1 kn[n z ! bru%es1 :i* s]ve to collect ! electricity set up by ! rotation ( ! armature4 ,^! bru%es are 9 electrical connection ) ! two t]m9als ( ! ma*9e ,f ,f'1 :5ce ! electric curr5t is transmitt$ :]e requir$2 ! latt] be+ also connect$ ) ! wire encircl+ ! field-magnet1 ,e4 ,:5 ! iron mass /&s 9 ! direction ( ! e>?'s magnetic m]idian1 ev5 if x h n previ\sly acquir$ a little magnetism f ! hamm]+1 etc41 to :i* x 0 subject$ dur+ fitt+1 x becomes weakly magnetic4 ,on caus+ ! armature to rotate by connect+ up ! pulley at ! back ( ! %aft 7n %[n 9 cut7 ) any s\rce ( p[]1 a v small curr5t is set up 9 ! wires ( ! armature1 due to ! weak magnetism ( ! iron mass ( ! field-magnet4 ,z ?is curr5t 7or a portion ( x7 is caus$ to circulate ar\nd ?is iron mass1 ?r\gh ! coils ( wire surr\nd+ ! field-magnet1 ?is latt] becomes m p[]fully magnetic 7,s #ac71 &1 be+ m magnetically active1 sets up a m p[]ful electrical di/urbance 9 ! armature4 ,?is increas$ electrical activity 9 ! armature increases ! magnetism ( ?is field-magnet z be=e1 & ?is aga9 reacts on ! armature2 & ^! cumulative effects rapidly increase1 until a limit is rea*$1 dep5d5t p>tly on ! spe$ ( rotation1 p>tly on ! magnetic saturation ( ! iron ( :i* ! dynamo is built up1 & p>tly on ! am\nt ( resi/ance 9 ! circuit4 ,,*apt] ,,ii4 ,,on ,,! ,,*oice ,,( ,,batt]ies ,,= ,,electric ,,bell ,,"w4 ,s #ag4 ,if we imm]se a /rip ( ord9>y comm]cial %eet z9c 9 dilute acid 7say sulphuric acid #a "p by measure1 wat] #af p>ts by measure#d71 we %all f9d t ! z9c is imm$iately act$ on by ! acid1 be+ rapidly corrod$ & dissolv$1 :ile at ! same "t a quantity ( bubbles ( gas are se5 to collect ar\nd1 & f9ally to be evolv$ at ! surface ( ! fluid 9 contact ) ! plate4 ,accompany+ ?is *emical action1 & v>y+ 9 a degree proportionate to ! int5sity ( ! action ( ! acid on ! z9c1 we f9d a m>k$ developm5t ( heat & electricity4 ,if1 :ile ! bubbl+ due to ! extrication ( gas be /ill proce$+1 we imm]se 9 ! same vessel a /rip ( silv]1 or copp]1 or a rod ( graphite1 tak+ c>e t contact does n take place betwe5 ! two elem5ts1 no p]ceptible *ange takes place 9 ! condition ( ?+s2 b if we cause ! two /rips to t\*1 ei!r by incl9+ ! upp] extremities s z to br+ !m 9 contact out ( ! fluid l a lett] ,lambda1 or by connect+ ! upp] extremities toge!r by means ( a piece ( wire 7or o!r conductor ( electricity71 or by caus+ _! l[] extremities 9 ! fluid to t\*1 we notice a v peculi> *ange4 ,! extrication ( bubbles ar\nd ! z9c /rip ceases entirely or almo/ entirely1 :ile ! o!r /rip 7silv]1 copp]1 or graphite7 becomes imm$iately ! seat ( ! evolution ( ! gase\s bubbles4 ,_h ^! exp]im5ts be5 p]=m$ ) *emically pure metallic z9c1 in/ead ( ! ord9>y impure comm]cial metal1 we %\ld h f\nd "s notewor?y diff]5ces 9 behavi\r4 ,9 ! fir/ place1 ! z9c w\ld h be5 absolutely unattack$ by ! acid be=e ! imm]sion ( ! o!r /rip2 &1 secondly1 all evolution ( gas w\ld entirely cease :5 contact betwe5 ! two /rips 0 brok54 ,footnote #d3 ,9 mix+ sulphuric acid ) wat]1 ! acid %\ld be add$ 9 a f9e /ream1 ) con/ant /irr+1 to ! wat]1 & n ! wat] to ! acid1 le/ ! great heat evolv$ %\ld cause ! acid to be scatt]$ ab\t4 ,z ! prop]ty :i* z9c possesses ( caus+ ! extrication ( gas 7"u ! above circum/ances7 has a consid]able influ5ce on ! effici5cy ( a batt]y1 x is well to und]/& ?or\ghly :at *emical action takes place :i* gives rise to ?is evolution ( gas4 ,s #ah4 ,all acids may be conv5i5tly reg>d$ z be+ built up ( two ess5tial portions1 viz43 fir/ly1 a /rongly electro-negative portion1 :i* may ei!r be a s+le body1 su* z *lor9e1 iod9e1 brom9e1 etc41 or a comp\nd radical1 su* z cyanog52 secondly1 ! /rongly electro-positive body hydrog54 ,repres5t+1 = brevity's sake1 hydrog5 by ! lett] ,h41 & *lor9e1 brom9e1 iod9e1 etc41 respectively by ,cl41 ,br41 & ,i41 ! con/itution ( ! acids d]iv$ f ^! bodies may be conv5i5tly repres5t$ by3-- ,h ,cl ,h ,br ,h ,i ---- ---- --- ,hydro*loric#e ,hydrobromic ,hydriodic ,acid4 ,acid4 ,acid4 ,footnote #e3 ,spirits ( salt4 & ! m complex acids1 9 :i* ! electro-negative compon5t is a comp\nd1 su* z sulphuric acid 7built up ( #a atom ( sulphur & #d atoms ( oxyg51 unit$ to #b atoms ( hydrog57 or nitric acid 7consi/+ ( #a nitrog5 atom1 #f oxyg5 atoms1 & #a hydrog5 atom71 may advantage\sly be reta9$ 9 memory by ! aid ( ! abbreviations3-- ,h#b,,s#d ,,hno#f ----------- ------- ,sulphuric & ,nitric ,acid4#f ,acid4#g ,footnote #f3 ,oil ( vitriol4 ,footnote #g3 ,aqua=tis4 ,:5 z9c does act on an acid1 x displaces ! hydrog5 conta9$ 9 x1 & takes its place2 ! acid los+ at ! same "t its *>act]i/ic s\rness & corrosiv5ess1 becom+1 z *emi/s say1 neutraliz$4 ,"o atom ( z9c c replace two atoms ( hydrog51 s t "o atom ( z9c c replace ! hydrog5 9 two equival5ts ( su* acids z conta9 only "o atom ( hydrog54 ,?is p[] ( displacem5t & replacem5t possess$ by z9c is n peculi> to ?is metal1 b is possess$ also by _m o!r bodies1 & is ( v common occurr5ce 9 *emi/ry2 & may be r\ghly lik5$ to ! sub/itution ( a new brick = an old "o 9 a build+1 or "o gird] = ano!r 9 an ar*4 ,x w be well1 !re=e1 to rememb] t 9 all batt]ies 9 :i* acids are us$ to excite electricity by _! behavi\r along ) z9c1 ! foll[+ *emical action w also take place1 accord+ to :i* acid is employ$3-- ,hydro*loric ,acid & ,z9c1 equal ,z9c ,*loride & ,hydrog5 ,gas4 #b;,h,cl ,zn ,zn,cl#b ,h#b or3-- ,sulphuric ,acid & ,z9c1 equal ,z9c ,sulphate & ,hydrog5 ,gas4 ,h#b,,s#d ,zn ,zn,s,o#d ,h#b ,or we may put ?is /atem5t into a g5]al =m1 cov]+ all cases 9 :i* z9c is act$ on by a comp\nd body conta9+ hydrog51 repres5t+ ! o!r or electro-negative portion ( ! comp\nd by ,x3-- ,zn ,h#b,x ,zn,x ,h#b ! f9al result be+ 9 e case ! corrosion & solution ( ! z9c1 & ! extrication ( ! hydrog5 gas displac$4 ,s #ai4 ,we le>n f ! prec$+ /atem5ts t no electricity c be manife/$ 9 a batt]y or cell 7z su* a comb9ation ( z9c acid & metal is call$7 )\t consumption ( z9c4 ,on ! contr>y1 we may safely say t ! m rapidly ! useful consumption ( z9c takes place1 ! great] w be ! electrical effects produc$4 ,b "h x mu/ be borne 9 m9d t if ! z9c is be+ consum$ :5 we are n us+ ! cell or batt]y1 t consumption is %e] wa/e1 q z mu* z if we 7 compell$ to burn fuel 9 an eng9e :e!r ! latt] 7 do+ "w or n4 ,= ?is reason ! use ( comm]cial z9c1 9 its ord9>y condition1 is n advisable 9 batt]ies 9 :i* acids are employ$1 s9ce ! z9c is consum$ 9 su*1 :e!r ! batt]y is call$ ^u to d electrical "w 7by plac+ its plates 9 connection ?r\gh "s conduct+ circuit7 or n4 ,?is s]i\s objection to ! employm5t ( comm]cial z9c c\ld be ov]come by ! employm5t ( *emically purifi$ z9c1 7 x n t ! price ( ?is latt] is s elevat$ z practically to preclude its use = ?is purpose4 ,=tunately1 x is possible to conf]1 on ! ord9>y crude z9c ( comm]ce1 ! p[] ( resi/+ ! attacks ( ! acid 7s long z ! plates are n metallically connect$2 or1 9 o!r words1 s long z ! circuit is brok571 by caus+ x to absorb sup]ficially a c]ta9 am\nt ( m]cury 7quicksilv]74 ,! modes ( do+ ?is1 :i* is te*nically kn[n z amalgamat+ ! z9c1 are v>i\s1 &1 z x is an op]ation :i* e "o :o has ! c>e ( batt]ies is frequ5tly call$ ^u to p]=m1 ! foll[+ work+ details w be f\nd useful3-- ,s #bj4 ,to amalgamate z9c1 x %\ld fir/ be wa%$ ) a /rong solution ( common wa%+ soda1 to remove grease1 !n r9s$ 9 runn+ wat]2 ! z9c plates1 or rods1 %\ld !n be dipp$ into a vessel conta9+ acidulat$ wat] 7,s #ag71 & z soon z bubbles ( hydrog5 gas beg9 to be evolv$1 transf]r$ to a l>ge flat di% conta9+ wat]4 ,:ile "h1 a few drops ( m]cury are p\r$ on ea* plate1 & caus$ to spread quickly ov] ! surface ( ! z9c by rubb+ briskly ) an old nail-bru% or too?-bru%4 ,"s op]ators use a k9d ( mop1 made ( pieces ( rag ti$ on ! end ( a /ick1 & !re is no objection to ?is2 o!rs recomm5d ! use ( ! f+]s = rubb+ 9 ! m]cury4 ,?is latt] plan1 especially if _m plates h to be done1 is v objectionable3 fir/ly1 on ! gr\nd ( heal?1 s9ce ! m]cury is sl[ly b surely absorb$ by ! sy/em1 giv+ rise to salivation1 etc42 &1 secondly1 because any jewell]y1 etc41 worn by ! we>] w be :it5$ & r5d]$ brittle4 ,:5 ! entire surface ( ! z9c becomes respl5d5t l a look+-glass1 ! rubb+ may cease1 & ! z9c plate be re>$ up on edge1 to all[ ! sup]flu\s m]cury to dra9 (f4 ,?is %\ld be collect$ = future op]ations4 ,x is important t ! m]cury us$ = ?is purpose %\ld be pure4 ,mu* comm]cial m]cury conta9s lead & t94 ,^! metals c be remov$ by all[+ ! m]cury to /& = "s "t 9 a vessel conta9+ dilute nitric acid1 occasional agitation be+ resort$ to1 9 ord] to br+ ! acid into g5]al contact ) ! m]cury4 ,all wa/e m]cury1 dra9+s1 bru%+s f old plates1 etc41 %\ld be ?us treat$ ) nitric acid1 & f9ally kept cov]$ ) wat]4 ,sprague1 9 8 admirable "w on electricity1 says3--,:5ev] ! z9c %[s a grey granul> surface 7or r be=e ?is71 bru% x well & re-amalgamate1 rememb]+ t a sav+ ( m]cury is no economy1 & a free use ( x no wa/e2 = x may all be recov]$ ) a little c>e4 ,keep a conv5i5t siz$ j>1 or vessel1 solely = wa%+ z9c 91 & bru% into ?is ! dirty grey p[d] :i* =ms1 & is an amalgam ( m]cury ) z9c1 lead1 t91 etc41 & =ms r\ghnesses :i* r$uce ! protection ( ! amalgamation4 ,roll$ %eet z9c %\ld always be us$ 9 pref]5ce to ca/4 ,?is latt] is v h>d to amalgamate1 & has less electro-motive p[]#h2 b = rods = use 9 por\s j>s1 & p>ticul>ly ) sal9e solutions1 ca/-z9c is v commonly us$4 ,9 ?is case great c>e %\ld be tak5 to use good z9c cutt+s1 remov+ any p>ts ) sold] on !m1 & us+ a little nitre z a flux1 :i* w remove a portion ( ! =eign metals4 ,footnote #h3 ,p[] to set up a curr5t ( electricity4 ,s #ba4 ,ano!r & v conv5i5t mode ( amalgamat+ z9c1 specially useful :]e solid rods or masses ( z9c are to be us$1 consi/s 9 weigh+ up ! z9c & sett+ aside f\r p>ts ( m]cury 7by weight7 = e hundr$ ( ! z9c ?us weigh$ up4 ,! z9c %\ld !n be melt$ 9 a ladle1 ) a little tall[ or res9 ov] ! top z a flux4 ,z soon z melt$1 ! m]cury %\ld be add$ 9 & ! mixture /irr$ ) a /ick4 ,x %\ld !n be p\r$ into m\lds ( ! desir$ %ape4 ,?is is1 p]haps1 ! be/ mode ( amalgamat+ ca/ z9cs4 ,s #bb4 ,"s op]ators recomm5d ! use ( m]curial salts 7su* z m]cury nitrate1 etc47 z advantage\s = amalgamat+2 b1 ap>t f ! fact t ^! salts are g5]ally sold at a high] rate ?an ! m]cury itself1 ! amalgamation result+1 unless a v consid]able "t be all[$ = ! m]curic salts to act1 is nei!r s deep nor s satisfactory z 9 ! case ( m]cury alone4 ,x may "h be not$1 t al?\gh ! effect ( m]cury 9 protect+ ! z9c is v m>k$ 9 ^? batt]ies 9 :i* acids are us$ z ! excit+ fluids1 yet ?is action is n s obs]vable 9 ! cases 9 :i* solutions ( salts are us$ z excit]s2 & 9 a few1 su* z ! ,daniell cell & its cong5]s1 ! use ( amalgamat$ z9c is positively a disadvantage4 ,s #bc4 ,if1 hav+ ?us amalgamat$ ! z9c plate ( ! little batt]y describ$ & figur$ at ,s #i1 we repeat ! exp]im5t !re9 illu/rat$1 namely1 ( jo9+ ! wires proce$+ f ! two plates ov] a susp5d$ magnetic ne$le1 & leave !m s unit$1 we %all f9d t ! magnetic ne$le1 :i* 0 orig9ally v mu* deflect$ out ( ! l9e ( ! magnetic m]idian 7nor? & s\?71 w v quickly return ne> to its old & normal position2 & ?is w be f\nd to take place long be=e ! z9c has be5 all consum$1 or ! acid all neutralis$4 ,( c\rse1 ?is po9ts to a rapid fall+ (f 9 ! transmission ( ! electric di/urbance along ! unit$ wires2 = _h t cont9u$ ( ! same int5sity1 ! deflection ( ! ne$le w\ld evid5tly h rema9$ ! same likewise4 ,:at1 !n1 c h caus$ ?is rapid loss ( p[]8 ,on exam9+ 7)\t remov+ f ! fluid7 ! surface ( ! copp] plate1 we %all f9d t x is lit]ally cov]$ ) a coat+ ( small bubbles ( hydrog5 gas1 &1 if we agitate ! liquid or ! plates1 _m ( !m w rise to ! surface1 :ile ! magnetic ne$le w at ! same "t give a l>g] deflection4 ,if we entirely remove ! plates f ! acid fluid1 & bru% ov] ! surface ( ! copp] plate ) a fea!r or small pl$get ( cotton wool fa/5$ to a /ick1 we %all f9d1 on aga9 imm]s+ ! plates 9 ! acid1 t ! effect on ! ne$le is almo/1 if n q1 z great z at fir/2 ?us prov+ t ! sudd5 loss ( electrical en]gy 0 greatly due to ! adhesion ( ! free hydrog5 gas to ! copp] plate4 ,?is peculi> ph5om5on1 :i* is g5]ally spok5 ( z ! pol>isation ( ! negative plate1 acts 9 a tw(old mann] t[>ds *eck+ ! electrical en]gy ( ! batt]y4 ,9 ! fir/ place1 ! lay] ( hydrog5 7be+ a bad conductor ( electricity7 pres5ts a great resi/ance to ! transmission ( electrical en]gy f ! z9c plate :]e x is set up to ! copp] 7or o!r7 plate :5ce x is transmitt$ to ! wires1 or electrodes4 ,aga91 ! copp] or o!r receiv+ plate1 9 ord] t ! electric en]gy %\ld be duly receiv$ & transmitt$1 %\ld be m electro-negative ?an ! z9c plate2 b ! hydrog5 gas :i* is evolv$1 & :i* ?us adh]es to ! negative plate1 is actually v highly electro-positive1 & ?us r5d]s ! copp] plate incapable ( receiv+ or transmitt+ ! electric di/urbance4 ,?is /ate ( ?+s may be r\ghly lik5$ to t ( two exactly equal & level tanks1 ,z & ,c1 connect$ by a /raight piece ( tub+4 ,if ,z be full & ,c h an outlet1 x is v evid5t t ,z c & w dis*>ge itself into ,c until exhau/$2 b if ,c be all[$ to fill up to ! same level z ,z1 !n no f>!r fl[ c take place betwe5 ! two4 ,x is1 !re=e1 v evid5t t to ensure any?+ l con/ancy 9 ! work+ ( a batt]y1 at lea/ until all ! z9c be consum$ or all ! acid exhau/$1 "s device = remov+ ! lib]at$ hydrog5 mu/ be put into practice4 ,! foll[+ are "s ( ! means t h be5 adopt$ by practical m53-- ,s #bd4 ,r\gh5+ ! surface ( ! negative plate1 :i* r5d]s ! escape ( ! hydrog5 gas easi]4 ,?is mode 0 adopt$ by ,smee 9 ! batt]y :i* be>s 8 "n4 ,x consi/s ( a %eet ( silv]1 plac$ betwe5 two plates ( z9c1 /&+ 9 a cell conta9+ dilute sulphuric acid1 z %[n at ,fig4 #e4 ,illu/ration3 ,fig4 #e4 ,! silv] %eet1 be=e be+ plac$ 9 position1 is plat9is$2 t is to say1 its surface is cov]$ 7by electro-deposition7 ) a coat+ ( plat9um1 9 ! =m ( a f9e black p[d]4 ,?is pres5ts innum]able po9ts ( escape = ! hydrog5 gas2 & = ?is reason ?is batt]y falls (f mu* less rapidly ?an ! pla9 z9c & smoo? copp] =m4 ,a modification ( ,smee's batt]y :i*1 ow+ to ! l>ge negative surface pres5t$1 is v advantage\s1 is ,walk]'s graphite cell4 ,9 ?is we h a plate ( z9c betwe5 two plates ( gas-c>bon 7scurf71 or graphite4 ,! surface ( ?is body is naturally mu* r\gh] ?an metal %eets2 & ?is r\ghness ( surface is fur!r assi/$ by coat+ ! surface ) plat9um1 z 9 ! case ( ! ,smee4 ,! *ief objection to ! use ( graphite is its porosity1 :i* causes x to suck up ! acid fluid 9 :i* ! plates /&1 & ?is1 ( c\rse1 corrodes ! brass connections1 or b9d+ screws4 ,o!r me*anical means ( remov+ ! hydrog5 h be5 sugge/$1 su* z bru%+ ! surface ( ! plate1 keep+ ! liquid 9 a /ate ( agitation by boil+ or siphon+2 b ! only really effici5t practical means ) :i* we are at pres5t acqua9t$ are *emical means4 ,?us1 if we c h pres5t at ! negative plate "s sub/ance :i* is gre$y ( hydrog51 & :i* %all absorb x or comb9e ) x1 we %all evid5tly h solv$ ! problem4 ,?is 0 fir/ effect$ by ,pr(essor ,daniell2 & ! batt]y kn[n by 8 "n /ill reta9s its position z "o ( ! simple/ & be/ ( ! con/ant =ms ( batt]y4 ,! t]m con/ant1 z appli$ to batt]ies1 does n mean t ! batt]y is a con/ancy1 & w run = ev]1 b simply t s long z !re is 9 ! batt]y any fuel 7z9c1 acid1 etc471 ! electrical output ( t batt]y w be con/ant4 ,! ,daniell cell consi/s ess5tially 9 a rod or plate ( z9c imm]s$ 9 dilute sulphuric acid1 & sep>at$ f ! copp] or collect+ plate by a por\s e>!n pot or cell4 ,ar\nd ! por\s cell1 & 9 contact ) ! copp] plate1 is plac$ a solution ( sulphate ( copp]1 :i* is ma9ta9$ saturate by keep+ cry/als ( sulphate ( copp] 7blue /one1 blue vitriol7 9 ! solution4 ,sulphate ( copp] is a comp\nd built up ( copp] ,cu1 & ( sulphur oxide ,,s#d4 ,:5 ! dilute sulphuric acid acts on ! z9c plate or rod 7,s #ah71 sulphate ( z9c is =m$1 :i* dissolves 9 ! wat]1 & hydrog5 is giv5 (f3-- ,zn ,h#b ,,s#d ,zn ,,s#d ,h#b4 ,z9c & sulphuric acid produce z9c sulphate & free hydrog54 ,n[ ?is free hydrog51 by a s]ies ( molecul> int]*anges1 is c>ri$ along until x passes ?r\gh ! por\s cell1 & f9ds itself 9 contact ) ! solution ( copp] sulphate4 ,"h1 z ! hydrog5 has a great] aff9ity =1 or is m gre$y (1 ! sulphur oxide1 ,,s#d1 ?an ! copp] is1 x turns ! latt] out1 takes its place1 sett+ ! copp] free1 & =m+1 ) ! sulphur oxide1 sulphuric acid4 ,! lib]at$ copp] goes1 & adh]es to ! copp] plate1 &1 f> f detract+ f its efficacy1 z ! lib]at$ hydrog5 w\ld h done1 actually increases its effici5cy1 z x is deposit$ 9 a r\gh5$ =m1 :i* pres5ts a l>ge surface = ! collection ( ! electricity4 ,! int]*ange :i* takes place :5 ! free hydrog5 meets ! sulphate ( copp] 7outside ! por\s cells7 is %[n 9 ! foll[+ equation3-- ,h#b ,cu ,,s#d ,h#b ,,s#d ,cu4 ,free hydrog5 & copp] sulphate produce sulphuric acid & free copp]4 ,illu/ration3 ,fig4 #f4 ,,daniell ,,cell4 ,s #be4 ,! orig9al =m giv5 to ?is1 ! ,daniell cell1 is %[n at ,fig4 #f1 9 :i* ,z is ! z9c rod /&+ 9 ! por\s pot ,p1 9 :i* is plac$ ! dilute sulphuric acid4 ,a conta9+ vessel1 ,v1 ( glaz$ e>!nw>e1 provid$ ) a p]=at$ %elf1 ,s1 on :i* are plac$ ! cry/als ( sulphate ( copp]1 s]ves to hold ! copp] %eet1 ,c1 & ! solution ( sulphate ( copp]4 ,t & ,t' are ! t]m9als f :i* ! electricity is l$ :]e desir$4 ,9 ano!r =m1 ! copp] %eet itself takes ! =m & replaces ! conta9+ vessel ,v2 & s9ce ! copp] is n corrod$1 b actually increases 9 ?ickness dur+ action1 ?is is a decid$ advantage4 ,a modification1 9 :i* ! por\s cell is replac$ by s& or by sawdu/1 is also con/ruct$1 & kn[n z ,m9otto's cell3 ?is1 ow+ to ! great] ?ickness ( ! por\s lay]1 (f]s m resi/ance1 & gives1 consequ5tly1 less curr5t4 ,by tak+ advantage ( ! great] specific gravity 7weight1 bulk = bulk7 ( ! solution ( sulphate ( copp] ov] t ( wat] or dilute sulphuric acid1 x is possible to con/ruct a batt]y :i* %all act 9 a mann] precisely simil> to a ,daniell1 )\t ! employm5t ( any por\s p>tition :atsoev]4 ,fig4 #g illu/rates ! con/ruction ( "o ( ^!1 kn[n z ,gravity ,daniells4 ,illu/ration3 ,fig4 #g4 ,,gravity ,,cell4 ,9 ?is we h a plate1 disc1 or spiral ( copp]1 ,c1 connect$ by an insulat$ copp] wire to ! t]m9al ,t'4 ,ov] ?is is plac$ a lay] ( cry/als ( copp] sulphate2 ! j> is !n fill$ ne>ly to ! top ) dilute sulphuric acid1 or ) a /rong solution ( sulphate ( z9c 7:i* is m la/+ 9 its effects1 b n s en]getic z ! dilute sulphuric acid71 & on ! surface ( ?is1 connect$ to ! o!r t]m9al1 ,t1 is all[$ to re/ a ?ick disc ( z9c1 ,z4 ,speak+ ( ^! cells1 ,pr(essor ,ayrton1 9 8 invaluable ,practical ,electricity1 says3--,all gravity cells h ! disadvantage t !y _c be mov$ ab\t2 o!rwise ! liquids mix1 & ! copp] sulphate solution1 com+ into contact ) ! z9c plate1 deposits copp] on x4 ,?is impairs ! action1 by caus+ ! z9c to act electrically1 l a copp] "o4 ,inde$1 )\t any %ak+1 ! liquids mix by diffusion1 ev5 :5 a por\s pot is employ$2 h5ce a ,daniell's cell is f\nd to keep 9 bett] ord] if x be always all[$ to s5d a weak curr5t :5 n 9 use1 s9ce ! curr5t uses up ! copp] sulphate solution1 in/ead ( all[+ x to diffuse4 ,! use ( a solution ( z9c sulphate to act on ! z9c rod1 or plate1 is always to be pref]r$ 9 ! ,daniell cell1 :5 long duration is ( m consequ5ce ?an en]getic action4 ,s #bf4 ,!re are _m o!r bodies :i* c be us$ 9 batt]ies to absorb ! hydrog5 set free4 ,( sev]al ( ^! we ne$ only take a pass+ notice1 z ! batt]ies furni%$ by _! use are unfit = electric bell "w4 ,( ^! we may m5tion nitric acid1 :i* readily p>ts ) a portion ( ! oxyg5 7,s #ah7 & reconv]ts ! free hydrog5 into wat]4 ,?is acid is us$ z ! depol>iz]#i 9 ! ,grove & 9 ! ,buns5 cell4 ,ano!r v en]getic depol>is] is *romic acid1 ei!r 9 solution1 9 dilute sulphuric acid1 or 9 ! =m ( potassic di*romate 7bi*romate ( pota%3 bi*rome74 ,z "o =m ( *romic cell has f\nd fav\r ) "s bell-fitt]s1 we %all /udy its peculi>ities f>!r on4 ,footnote #i3 ,depol>iz] is ! te*nical "n giv5 to any body :i*1 by absorb+ ! free hydrog51 removes ! false pol>ity ( ! negative plate4 ,ano!r class ( bodies :i* readily "p ) _! oxyg51 & ?us act z depol>is]s1 are ! oxides ( lead & manganese4 ,?is latt] oxide =ms ! basis ( "o ( ! mo/ useful cells = electric bell "w1 namely3 ! "o kn[n z ! ,leclan*'e4 ,z ! batt]y has be51 & w probably rema91 long a fav\rite1 ! next p>agraph w be devot$ to its consid]ation4 ,s #bg4 ,! ,leclan*'e cell1 9 its orig9al =m1 consi/s 9 a rod or block ( gas c>bon 7retort scurf3 graphite7 /&+ 9 an upright por\s pot4 ,ar\nd ?is1 s z to rea* ne>ly to ! top ( ! por\s cell1 is tightly pack$ a mixture ( little lumps ( graphite & black oxide ( manganese 7manganic dioxide3 black wad71 ! por\s cell itself be+ plac$ 9 an out] conta9+ vessel1 :i* usually takes ! =m ( a squ>e glass bottle4 ,a z9c rod /&s 9 "o corn] ( ! bottle1 & is prev5t$ f com+ into actual contact ) ! por\s cell by hav+ an indi>ubb] r+ slipp$ ov] its upp] & l[] extremities4 ,! glass conta9+ vessel is !n fill$ to ab\t two-?irds ( its height ) a solution ( ammonium *loride 7sal ammoniac7 9 wat]1 ( ! /r5g? ( ab\t #b oz4 ( ! salt to ea* p9t ( wat]4 ,?is soon p]meates ! por\s cell & rea*es ! mixture inside4 ,! g5]al appe>ance ( ! ,leclan*'e cell is well %[n at ,fig4 #h4 ,illu/ration3 ,fig4 #h4 ,9 ord] to ensure a l>ge surface ( contact = ! t]m9al ( ! c>bon rod or plate1 x is cu/om>y to ca/ a lead5 cap on ! top !re(2 &1 z ! porosity ( ! graphite1 or c>bon1 is v apt to all[ ! fluid 9 ! batt]y to creep up to & corrode ! t]m9al1 & ?us oppose resi/ance to ! passage ( electricity1 ! upp] end ( ! c>bon1 be=e ! lead cap is ca/ on1 is soak$ = "s "t 9 melt$ p>aff9 wax1 at a temp]ature ( #aaj deg4 ,c5tigrade3 t is some:at hott] ?an boil+ wat] heat4 ,?is1 if left on ! outside1 w\ld prev5t ! passage ( electricity almo/ entirely2 s lat]al holes are drill$ into ! c>bon be=e ! cap is f9ally ca/ on4 ,! action t takes place 9 ! ,leclan*'e cell may be summ>is$ z foll[s3-- ,:5 ! z9c1 ,zn1 is act$ on by ! ammonium *loride1 #b,,nh#d;,cl1 ! z9c seizes ! *lor9e & =ms ) x z9c *loride1 ,zn,cl#b1 :ile ! ammonium1 #b,,nh#d1 is lib]at$4 ,b ?is ammonium1 #b,,nh#d1 does n escape4 ,be+ electro-positive1 x is impell$ t[>ds ! negative plate1 & 9 its passage !reto meets ) ano!r molecule ( ammonium *loride1 f :i* x displaces ! ammonium1 9 ?is wise3 #b,,nh#d #b,,nh#d;,cl #b,,nh#d;,cl #b,,nh#d2 9 o!r words1 ?is electro-positive ammonium is able1 by virtue ( its electrical *>ge1 to displace ! ammonium f ! comb9$ *loride4 ,9 s do+1 x sets ! lib]at$ ammonium 9 an electro-positive condition1 z x 0 itself1 los+ at ! same "t its electrical *>ge4 ,?is int]*ange ( molecules goes on 7z we saw 9 ! case ( ! ,daniell's cell1 ,s #bd7 until ! surface ( ! c>bon is rea*$4 ,"h1 z !re is no m ammonium *loride to decompose1 ! ammonium #b,,nh#d imm$iately splits up into ammonia #b,,nh#c & free hydrog5 ,h#b4 ,! ammonia escapes1 & may be detect$ by its smell2 :ile ! hydrog5 ,h#b1 f9d+ itself 9 contact ) ! oxide ( manganese1 #b,mn,o#b1 seizes "o atom ( its oxyg51 ,o1 becom+ !reby conv]t$ into wat] ,h#b,o2 :ile ! manganese dioxide1 #b,mn,o#b1 by los+ "o atom ( oxyg51 is r$uc$ to ! =m ( a l[] oxide ( manganese1 kn[n z manganese sesquioxide1 ,mn#b,o#c4 ,express$ 9 symbols1 ?is action may be =mulat$ z bel[3-- ,9 ! z9c comp>tm5t-- ,zn #b,,nh#d;,cl ,zn,cl#b #b,,nh#c ,h#b ,9 ! p]oxide ( manganese comp>tm5t-- ,h#b #b,mn,o#b ,mn#b,o#c ,h#b,o4 ,ammonia gas !re=e sl[ly escapes :ile ?is batt]y is 9 action1 & ?is corrodes all ! brass "w ) :i* x comes into contact1 produc+ a blui% gre5 v]digris4 ,if !re be n suffici5t ammonium *loride 9 solution1 ! wat] alone acts on ! z9c3 z9c oxide is produc$1 :i* r5d]s ! solution milky4 ,%\ld ?is be ! case1 m sal ammoniac mu/ be add$4 ,x is f\nd t = e #ej gra9s ( z9c consum$ 9 ?is batt]y1 ab\t #hb gra9s ( sal ammoniac & #abd gra9s ( manganese dioxide are ne$$ to neutralize ! hydrog5 set free4 ,x is ess5tial = ! effici5t work+ ( ?is batt]y t bo? ! manganese dioxide & ! c>bon %\ld be free f p[d]1 o!rwise x w cake toge!r1 prev5t ! passage ( ! liquid1 & pres5t a mu* small] surface to ! electricity1 ?an if 9 a granul> =m4 ,= ?is reason1 t manganese dioxide %\ld be pref]r$ :i* is kn[n z ! ne$le =m1 & bo? ?is & ! c>bon %\ld be sift$ to remove du/4 ,s #bh4 ,9 ! admirable s]ies ( pap]s on electric bell fitt+ :i* 0 publi%$ 9 ! ,engli% ,me*anic1 ,mr4 ,f4 ,c4 ,allsop1 speak+ ( ! ,leclan*'e cell1 says3--,a sev]e & prolong$ te/1 ext5d+ ov] _m ye>s1 has prov$ t = g5]al electric bell "w ! ,leclan*'e has no equal2 ?\gh1 9 l>ge hotels1 etc41 :]e ! "w is likely to be v heavy1 x may1 p]haps1 be pref]able to employ a =m ( ! ,full] bi*romate batt]y4 ,x is v important t ! batt]y employ$ %\ld be a ?or\ghly reliable "o & set up 9 a prop] mann]1 z a failure 9 ! batt]y causes a breakd[n 9 ! communication ?r\gh\t ! :ole build+1 :il/ ! failure ( a pu% or wire only affects t portion ( ! build+ 9 :i* ! pu% or wire is fix$4 ,a common fault is t ( putt+ 9 7) a view to economy7 only j en\gh cells 7:5 fir/ set up7 to d ! necess>y "w4 ,?is is false economy1 z :5 ! cells are b slightly exhau/$ ! batt]y p[] becomes insuffici5t2 :]eas1 if ano!r cell or two _h be5 add$1 ! batt]y w\ld h run a mu* long] "t )\t r5ewal1 ow+ to ! fact t ea* cell c\ld h be5 r$uc$ to a l[] /ate ( exhau/ion1 yet /ill ! batt]y w\ld h furni%$ ! necess>y p[]2 & ! writ] has always f\nd t ! extra exp5se ( ! surplus cells is fully repaid by ! increas$ l5g? ( "t ! batt]y runs )\t r5ewal4 ,s #bi4 ,ano!r =m ( ,leclan*'e1 f :i* great ?+s 7 expect$ at its introduction1 is ! "o kn[n z ! ,agglom]ate block1 f ! fact t1 in/ead ( simply plac+ ! c>bon & manganese toge!r loosely 9 a por\s cell1 solid blocks are =m$ by compress+ ^! mat]ials1 "u a pressure ( sev]al tons1 ar\nd a c5tral c>bon core1 to :i* ! t]m9al is atta*$ 9 ! usual mann]4 ,! foll[+ are "s ( ! compositions us$ 9 ! manufacture ( agglom]ate blocks3-- ,no4 #a4 ,manganese dioxide #dj p>ts4 ,p[d]$ gas c>bon #ee ,gum lac res9 #e ,no4 #b4 ,manganese dioxide 7pyrolusite7 #dj p>ts4 ,gas c>bon 7p[d]$7 #eb ,gum lac res9 #e ,potassium bisulphate #c ,^! are to be ?or\ghly incorporat$1 =c$ into /eel m\lds 7conta9+ ! c5tral c>bon core7 at a temp]ature ( #ajj deg4 ,c4 7#bab deg4 ,fahr471 "u a pressure ( #cjj atmosph]es1 say #d1ejj lbs4 to ! squ>e in*4 ,no4 #c4 ,b>bi] & ,leclan*'e's ,pat5t4 ,manganese dioxide #di p>ts4 ,graphite #dd ,pit* 7brai gras7 #i ,sulphur #c_/e ,wat] #b_/e ,! mat]ials hav+ be5 r$uc$ to f9e p[d]1 & ! proportion ( wat] /at$ hav+ be5 add$1 are intimately mix$ toge!r by h& or me*anically4 ,! moi/ mixture is m\ld$ at ! ord9>y temp]ature1 ei!r by a simple compress+ press1 or by a press 9 :i* two pi/ons mov+ t[>ds ea* o!r compress ! block on two opposite faces2 or ! mixture may be compress$ by draw+1 z 9 ! manufacture ( electric light c>bon4 ,aft] compression1 ! products are suffici5tly solid to be manipulat$4 ,!y are !n put 9 a /ove1 or ov51 ! temp]ature ( :i* is gradually rais$ to ab\t #cej deg4 ,c4 7ab\t #ffb deg4 ,fahr472 a temp]ature :i* is insuffici5t to decompose ! depol>is+ sub/ance 7manganese dioxide71 b suffici5t to drive out fir/ ! volatile p>ts ( ! agglom]at+ mat]ial1 & !n to trans=m its fix$ p>ts 9 a body unattackable by ! ammonia ( ! cell4 ,dur+ ! gradual heat+1 or bak+1 :i* la/s ab\t two h\rs1 :at rema9s ( ! wat] 9 ! agglom]ate is driv5 (f2 !n come ! m volatile oils conta9$ 9 ! pit*1 & f9ally ! sulphur4 ,! sulphur is add$ to ! mixture1 n z an agglom]ative1 b z a *emical re-ag5t 7& ?is is a *>act]i/ic feature 9 ! inv5tion71 act+ on :at rema9s ( ! pit*1 z x acts on all c>bo-hydrides at a high temp]ature1 trans=m+ x p>tially into volatile sulphurett$ comp\nds1 :i* are expell$ by ! heat1 & p>tially into a fix$ & unattackable body1 some:at simil> to vulcanite4 ,! action ( ! sulphur on ! pit* c v well be lik5$ to its action on ca\t*\c 7:i* is likewise a hydro-c>bon7 dur+ ! process ( vulcanisation4 ,^! agglom]ate blocks1 h[ev] prep>$1 are plac$ 9 glass or porcela9 conta9+ vessels1 z %[n 9 ,fig4 #i1 ) a rod ( z9c1 sep>at$ f actual contact ) ! c>bon by means ( a c\ple ( cross$ indi>ubb] b&s1 :i* s]ve at ! same "t to hold ! z9c rods upright4 ,! excit+ solution1 z 9 ! case ( ! ord9>y ,leclan*'e consi/s 9 a solution ( ammonium *loride4 ,illu/ration3 ,fig4 #i4 ,among ! v>i\s advantages claim$ = ! agglom]ate =m ( ,leclan*'e ov] ! ord9>y type1 may be m5tion$ ! foll[+3-- #a/4--,! depol>is+ p[] ( ! manganese oxide is us$ to ! be/ advantage1 & t1 ow+ to ?is1 ! electro-motive =ce ( ! batt]y is kept at ! same po9t4 #bnd4--,t1 ow+ to ! abs5ce ( ! por\s cell1 !re is less int]nal resi/ance 9 ! batt]y & !re=e m available curr5t4 #crd4--,t ! resi/ance ( ! batt]y rema9s pretty con/ant1 :atev] "w be put ^u x4 #d?4--,t1 ow+ to ! fact t ! liquid comes into contact ) bo? elem5ts imm$iately1 ! batt]y is ready = use directly on be+ *>g$4 #e?4--,t ! r5ewal or re*>g+ is exce$+ly easy1 s9ce ! elem5ts c be remov$ toge!r1 fre% solution add$1 or new depol>is+ blocks sub/itut$4 ,b :5 ?is batt]y came to be put to ! te/ ( practical "w1 x 0 f\nd ! block =m c\ld n be cr$it$ ) all ^! advantages1 & t _! *ief sup]iority ov] ! old cell consi/$ r 9 _! l[] int]nal resi/ance ?an 9 any?+ else4 ,ev5 ?is is n an advantage 9 ! case ( bell "w1 except :5 sev]al bells are arrang$ 9 p>allel1 s t a l>ge curr5t is requir$4 ,! blocks c]ta9ly pol>ise m quickly ?an ! old =m1 & x does n appe> t !y depol>ise any m rapidly4 ,probably ! enorm\s pressure to :i* ! blocks are subject$1 9 ! fir/ two processes1 r5d]s ! composition almo/ imp]meable to ! passage ( ! fluid1 s t depol>isation _c take place v rapidly4 ,ano!r & s]i\s objection to ^! blocks is t1 aft] a little "w1 pieces break away f ! blocks & settle on ! z9c4 ,?is sets up a %ort circuit1 & ! z9cs are consum$ :e!r ! batt]y is 9 action or n4 ,! au?or has _h no opportunity = mak+ any practical te/s ) ! blocks prep>$ by process ,no4 #c1 b he is "u ! impression t ! blocks w\ld be ev5 m friable ?an ^? prep>$ "u great] pressure4 ,s #cj4 ,a ?ird =m ( ,leclan*'e1 & "o :i* has giv5 consid]able satisfaction1 is ! "o kn[n z ,judson's ,pat5t4 ,?is consi/s1 z %[n at ,fig4 #aj1 9 a cyl9d] ( corrugat$ c>bon encas$ 9 an out] coat+ ( an insulat+ composition4 ,inside ! cell are two or m ?9 c>bon %eets1 cem5t$ to ! sides ( ! cell by ,pr\t's ela/ic glue1 or "s simil> comp\nd1 s z to leave spaces1 :i* are fill$ 9 ) granul> c>bon & manganese4 ,! surface ( ! plates is p]=at$1 s z to all[ ready access to ! excit+ fluid4 ,! z9c rod1 :i* is affix$ to ! cov]1 /&s 9 ! c5tre ( ! cell1 t\*+ x at no "p4 ,ow+ to ! v l>ge surface pres5t$ by ! corrugations 9 ! c>bon1 & by ! p]=at$ c>bon plates1 ! int]nal resi/ance ( ?is =m ( batt]y is v l[2 h5ce ! curr5t1 if employ$ aga9/ a small out] resi/ance1 is l>ge4 ,b ?is1 except 9 ! case ( bells arrang$ 9 p>allel1 is ( no great advantage4 ,illu/ration3 ,fig4 #aj4 ,s #ca4 ,! ord9>y =m ( ,leclan*'e is f\nd 9 m>ket 9 ?ree sizes1 viz41 ,no4 #a1 ,no4 #b1 & ,no4 #c4 ,un=tunately1 all mak]s d n use ^! numb]s 9 ! same mann]1 s t :ile "s call ! smalle/1 or p9t size1 ,no4 #a1 o!rs give ?is "n to ! l>ge/1 or ?ree-p9t1 size4 ,no4 #b is always qu>t size1 & ?is is ! "o commonly employ$4 ,:5 sev]al cells are employ$ to "w a numb] ( bells1 x is well1 9 ord] t !y may n receive injury1 t !y be enclos$ 9 a wood5 box4 ,z x is necess>y t ! batt]ies %\ld be inspect$ f "t to "t1 boxes are specially made ) d\bl$ h+$ top & side1 s t :5 ! cat* is releas$ ^! fall flat2 ?us admitt+ ( easy inspection or removal ( any individual cell4 ,?is =m ( batt]y box is %[n at ,fig4 #aa4 ,illu/ration3 ,fig4 #aa4 ,,batt]y ,,9 ,,box4 ,s #cb4 ,!re are c]ta9 ills to :i* ! ,leclan*'e cells are liable t require notice "h4 ,! fir/ is creep+4 ,by creep+ is meant ! gradual cry/allisation ( ! sal ammonium up ! inside & r\nd ! outside ( ! glass conta9+ j>4 ,!re are two modes ( prev5t+ ?is4 ,! fir/ consi/s 9 fill+ 9 ! neck ) melt$ pit*1 two small funnel-l tubes be+ previ\sly ins]t$ to admit ( ! addition ( fre% sal ammoniac solution1 & = ! escape ( gas4 ,?is mode _c be recomm5d$1 z x is almo/ impossible to remove ! pit* 79 case x be requir$ to r5ew ! z9c1 etc47 )\t break+ ! glass vessel4 ,! be/ way to remove ! pit* is to place ! cell 9 a l>ge saucepan ( cold wat]1 & set x on a fire until ! wat] boils4 ,! pit* is1 by ?is treatm5t1 s f> s(t5$ t ! elem5ts c be remov$ & ! pit* scrap$ away ) a knife4 ,illu/ration3 ,fig4 #ab4 ,by f> ! bett] mode is to rub r\nd ! inside & outside ( ! neck ( ! j> ) tall[1 or melt$ p>aff9 wax1 to ! dep? ( an in* or !reab\ts4 ,?is effectually prev5ts creep+ & ! consequ5t loss ( curr5t4 ,messrs4 ,g5t1 ( ,leice/]1 h introduc$ a v neat modification ( ! ,leclan*'e cell1 ) a view to obviate altoge!r ! evils d]iv+ f creep+4 ,?is cell is illu/rat$ at ,fig4 #ab1 & ! foll[+ is ! description suppli$ by ! pat5tees3--,all :o h _h exp]i5ce ( batt]ies 9 :i* a solution ( salts is us$ are aw>e ( ! difficulty exp]i5c$ 9 prev5t+ x creep+ ov] ! outside ( ! j>1 caus+ local loss1 & (t5times empty+ ! j> ( its solution4 ,_m devices h be5 tri$ to prev5t ?is1 b ! only effectual "o is our pat5t insulat$ j>1 9 :i* a recess surr\nds ! top ( ! j>1 ?is recess be+ fill$ ) a mat]ial to :i* ! salts w n adh]e1 ?us keep+ ! outside ( ! j> p]fectly clean4 ,x is specially adapt$ = use 9 hot climates1 & is ! only cell 9 :i* j>s may t\* ea* o!r & yet reta9 _! insulations4 ,we confid5tly recomm5d a trial ( ?is cell4 ,its price is b little 9 excess ( ! ord9>y ,leclan*'e4 ,! batt]y %\ld be set up 9 z cool a place z possible1 z heat is v conducive to creep+4 ,x is also important t ! batt]y %\ld be plac$ z ne> z conv5i5t to ! bell4 ,sometimes ! z9cs are se5 to become coat$ ) a black sub/ance1 or cov]$ ) cry/als1 rapidly wa/+ away at ! same "t1 al?\gh do+ little or no "w2 a /rong smell ( ammonia be+ giv5 (f at ! same "t4 ,:5 ?is occurs1 x po9ts to an electrical leakage1 or %ort circuit1 & ?is1 ( c\rse1 rapidly exhau/s ! batt]y4 ,x is ( ! utmo/ importance to ! effective work+ ( any batt]y t n ! slighte/ leakage or local action %\ld be all[$ to take place4 ,h[ev] slight su* loss be1 x w ev5tually ru9 ! batt]y4 ,?is leakage may be tak+ place 9 ! batt]y1 z a por\s cell may be brok51 & c>bon may be t\*+ ! z9c2 or out ( ! batt]y1 along ! conduct+ wires1 by "o t\*+ ! o!r1 or ?r\gh p>tial conductivity ( a damp wall1 a metallic /aple1 etc41 or by creep+4 ,if loss or local action has tak5 place1 x is be/1 aft] discov]+ & repair+ ! faults 7see also te/+ wires71 to replace ! old z9cs by new ones1 :i* are n co/ly4 ,s #cc4 ,!re is yet a modification ( ! ,leclan*'e :i* is sometimes us$ to r+ ! l>ge bells 9 hotels1 etc41 kn[n z ! ,leclan*'e rev]s$1 s9ce ! z9c is plac$ 9 ! por\s pot1 ?is latt] be+ /ood 9 ! c5tre ( ! /onew>e j>1 ! space betwe5 ! two be+ pack$ ) brok5 c>bon & manganese dioxide4 ,by ?is means a v mu* l>g] negative surface is obta9$4 ,9 ! ,gr5et cell1 ! por\s cell is replac$ by a canvas bag1 :i* is pack$ full ( lumps ( graphite & c>bon dioxide1 a c5tral rod ( c>bon be+ us$ z ! electrode4 ,?is may be us$ 9 out-(-!-way places :]e por\s cells are n readily obta9able1 b ,i _c recomm5d !m = durability4 ,s #cd4 ,! only o!r type ( batt]y :i* x w be ne$ful to notice 9 connection ) bell "w is "o 9 :i* ! depol>is] is ei!r *romic acid or a comp\nd ( *romic acid ) pota% or lime4 ,*romic acid consi/s ( hydrog5 unit$ to ! metal *romium & oxyg54 ,potassic di*romate 7bi*romate ( pota%3 bi*rome7 conta9s potassium1 *romium1 & oxyg54 ,if we repres5t potassium by ,k1 *romium by ,cr1 & oxyg5 by ,o1 we c get a fair idea ( its con/itution by express+ x z ,k#b;,cr#b,o#g1 by :i* x is %[n t "o molecule ( ?is body conta9s two atoms ( potassium unit$ to two atoms ( *romium & sev5 atoms ( oxyg54 ,bi*romate ( pota% readily p>ts ) its oxyg52 & x is ^u ?is1 & ^u ! relatively l>ge am\nt ( oxyg5 x conta9s1 t its effici5cy z a depol>is] dep5ds4 ,un=tunately1 bi*romate ( pota% is n v soluble 9 wat]2 "o p9t ( wat] w n take up mu* m ?an ?ree ounces ( ?is salt4 ,h5ce1 ?\gh ! solution ( potassium bi*romate is an excell5t depol>is] z long z x conta9s any ( ! salt1 x soon becomes exhau/$4 ,:5 bi*romate ( pota% is us$ 9 a cell along ) sulphuric acid & wat]1 sulphate ( pota% & *romic acid are =m$1 ?us3-- ,k#b;,cr#b,o#g ,h#b,,s#d ,h#b,o ,k#b,,s#d #b;,h#b;,cr,o#d ---------------- ----------- ------ ----------- ------------- #a molecule ( #a molecule #a give #a molecule #b molecules bi*rome4 ( molecule ( ( sulphuric ( sulphate *romic acid4 wat]4 ( pota%4 acid4 ,f ?is we le>n t be=e ! potassium bi*romate ent]s into action 9 ! batt]y1 x is resolv$ into *romic acid4 ,*romic acid is n[ prep>$ *eaply on a l>ge scale1 s t potassium bi*romate may always be advantage\sly replac$ by *romic acid 9 ^! batt]ies2 ! m s z *romic acid is extremely soluble 9 wat]4 ,9 ! pres5ce ( ! hydrog5 evolv$ dur+ ! action ( ! batt]y 7,s #ah7 *romic acid p>ts ) a portion ( its oxyg51 =m+ wat] & sesquioxide ( *romium1 ,cr#b,o#c1 & ?is1 f9d+ itself 9 contact ) ! sulphuric acid1 always us$ to increase ! conductivity ( ! liquid1 =ms sulphate ( *romium4 ,! action ( ! hydrog5 ^u ! *romic acid is %[n 9 ! foll[+ equation3-- #b;,h#b;,cr,o#d #c;,h#b #e;,h#b,o ,cr#b,o#c ------------- ------ ------- ----------- #b molecules ( #c molecules #e molecules #a molecule *romic ( give ( wat]4 ( acid4 hydrog54 *romium sesquioxide4 ,illu/ration3 ,fig4 #ac4 ,s #ce4 ,! bottle =m ( ! bi*romate or *romic acid batt]y 7z illu/rat$ at ,fig4 #ac7 is mu* employ$ :]e p[]ful curr5ts ( %ort duration are requir$4 ,x consi/s ( a globul> bottle ) a r long wide neck1 9 :i* are plac$ two long n>r[ graphite plates1 electrically connect$ to ea* o!r & to "o ( ! b9d+ screws on ! top4 ,betwe5 ^! two plates is a slid+ rod1 c>ry+ at its l[] extremity ! plate ( z9c4 ,?is slid+ rod c be l[]$ & rais$1 or reta9$ 9 any position1 by means ( a set screw4 ,! z9c is 9 metallic connection ) ! o!r b9d+ screw4 ,?is batt]y 7:i*1 ow+ to ! facility ) :i* ! z9c c be remov$ f ! fluid1 is extremely conv5i5t & economical = %ort exp]im5ts7 may be *>g$ ) ei!r ( ! foll[+ fluids3-- ,,fir/ ,,recipe4 ,bi*romate ,solution4 ,bi*romate ( pota% 7f9ely p[d]$7 #c oz4 ,boil+ wat] #a p9t4 ,/ir ) a glass rod1 all[ to cool1 !n add1 9 a f9e /ream1 ) con/ant /irr+1 ,/rong sulphuric acid 7oil ( vitriol7 #c fluid oz4 ,! mixture %\ld be made 9 a glaz$ e>!rn vessel1 & all[$ to cool be=e us+4 ,,second ,,recipe4 ,*romic ,acid ,solution4 ,*romic acid 7*romic trioxide7 #c oz4 ,wat] #a p9t4 ,/ir toge!r till dissolv$1 !n add gradually1 ) /irr+1 ,sulphuric acid #c oz4 ,?is also mu/ n be us$ till cold4 ,9 ei!r case ! bottle mu/ n be m ?an ?ree p>ts fill$ ) ! excit+ fluid1 to all[ pl5ty ( room = ! z9c to be drawn "r out ( ! liquid :5 n 9 use4 ,s #cf4 ,! effects giv5 by ! above batt]y1 ?\gh v p[]ful1 are too transi5t to be ( any s]vice 9 cont9u\s bell "w4 ,! foll[+ modification1 kn[n z ! ,full] cell1 is1 h[ev]1 useful :]e p[]ful curr5ts are requir$1 &1 :5 c>efully set up1 may be made to d good s]vice = five or six mon?s at a /ret*4 ,! ,full] cell consi/s 9 an out] glass or glaz$ e>!rn vessel1 9 :i* /&s a por\s pot4 ,9 ! por\s pot is plac$ a l>ge block ( amalgamat$ z9c1 t is ca/ ar\nd a /\t copp] rod1 :i* c>ries ! b9d+ screw4 ,?is rod mu/ be c>efully protect$ f ! action ( ! fluid1 by be+ cas$ 9 an indi>ubb] tube4 ,! amalgamation ( ! z9c mu/ be kept up by putt+ a small quantity ( m]cury 9 ! por\s cell4 ,! por\s cells mu/ be p>aff9$ to )9 ab\t half an in* ( ! bottom1 to prev5t too rapid diffusion ( ! liquids1 & ! cells !mselves %\ld be *os5 r ?ick & close 9 texture1 z o!rwise ! z9c w be rapidly corrod$4 ,wat] alone is us$ z ! excit+ fluid 9 ! por\s cell along ) ! z9c4 ,speak+ ( ?is =m ( cell1 ,mr4 ,p]r5-,maycock says3--,! base ( ! z9c is m act$ on 7:5 bi*romate cry/als are us$71 because ! por\s cells re/ on ! cry/als2 !re=e let x be well p>aff9$1 z also ! top edge4 ,in/ead ( p>aff9+ ! pot 9 /rips all r\nd 7z _m op]ators d7 p>aff9 ! pot all r\nd1 except at "o /rip ab\t half an in* wide1 & let ?is face ! c>bon plate4 ,if ?is be done1 ! diff]5ce 9 int]nal resi/ance betwe5 ! cell ) p>aff9$ pot & ! same cell ) pot unp>aff9$ w be little2 b if ! portion t is unp>aff9$ be turn$ away f ! c>bon1 x w make v ne>ly an additional #a ohm resi/ance4 ,x is necess>y to h an ounce or s ( m]cury 9 ea* por\s cell1 cov]+ ! foot ( ! z9c2 or ! z9cs may be ca/ %ort1 b ( l>ge diamet]1 holl[$ out at ! top to hold m]cury1 & susp5d$ 9 ! por\s pot4 ,! z9c is less act$ on !n1 = :5 ! bi*romate solution diffuses into ! por\s pot1 x obvi\sly does s m at ! bottom ?an at ! top4 ,illu/ration3 ,fig4 #ad4 ,fig4 #ad illu/rates ! =m usually giv5 to ! modification ( ! ,full] cell z us$ = bell & signall+ "w4 ,s #cg4 ,be=e leav+ ! subject ( batt]ies1 !re are c]ta9 po9ts 9 connection !re) t x is absolutely ess5tial t ! practical man %\ld und]/&1 9 ord] to be able to execute any "w satisfactorily4 ,9 ! fir/ place1 x mu/ be borne 9 m9d t a cell or batt]y1 :5 at "w1 is cont9ually sett+ up electric undulations1 some:at 9 ! same way t an organ pipe1 :5 actuat$ by a pressure ( air1 sets up a cont9u\s s\nd wave4 ,:atev] sets up ! electric di/urbance1 :e!r x be ! action ( sulphuric acid on z9c1 or cau/ic pota% on iron1 etc41 is call$ electromotive =ce1 g5]ally abbreviat$ ,e4,m4,f4 ,j 9 ! same mann] t ! organ pipe c\ld give no s\nd if ! pressure ( air 7 alike inside & out1 s ! cell1 or batt]y1 _c possibly give curr5t1 or evid5ce ( electric fl[1 unless !re is "s means provid$ to all[ ! t5sion1 or increas$ atomic motion set up by ! electromotive =ce1 to di/ribute itself along "s l9e ( conductor or conductors n subject$ to ! same pressure or ,e4,m4,f4 ,9 o!r words1 ! curr5t ( electricity w always t5d to fl[ f t body :i* has ! highe/ t5sion1 t[>ds ! body :]e ! /ra9 or t5sion is less4 ,9 a cell 9 :i* z9c & c>bon1 z9c & copp]1 or z9c & silv] are ! two elem5ts1 ) an acid z an excitant1 ! z9c dur+ ! action ( ! acid becomes ( high] pot5tial ?an ! o!r elem5t1 & consequ5tly ! undulations take place t[>ds ! negative plate 7be x c>bon1 copp]1 or silv]74 ,b by ?is v action ! negative plate imm$iately rea*es a po9t ( equal t5sion1 s t no curr5t is possible4 ,if1 h[ev]1 we n[ connect ! two plates toge!r by means ( any conductor1 say a copp] wire1 !n ! /ra9 to :i* ! c>bon plate is subject$ f9ds its exit along ! wire & ! z9c plate1 :i* is cont9ually los+ its /ra9 "u ! influ5ce ( ! acid1 be+ ?us at a l[] pot5tial 7electrical level1 /ra97 ?an ! c>bon1 c & does actually take 9 & pass on ! electric vibrations4 ,x is !re=e evid5t t no true curr5t c pass unless ! two elem5ts ( a batt]y are connect$ up by a conductor4 ,:5 ?is connection is made1 ! circuit is call$ a clos$ circuit4 ,if1 on ! contr>y1 !re is no electrical connection betwe5 ! negative & positive plates ( a cell or batt]y1 ! circuit is said to be op51 or brok54 ,x may be t ! circuit is clos$ by "s means t is n desirable1 t is to say1 along "s l9e or at "s "t :5 & :]e ! fl[ is n want$2 z1 = in/ance1 ! outside ( a cell may be wet1 & "o ( ! wires re/+ aga9/ x1 :5 ( c\rse leakage w take place z ! circuit w be clos$1 ?\gh no useful "w w be done4 ,on ! o!r h&1 we may actually take advantage ( ! practically unlimit$ am\nt ( ! e>?'s surface1 & ( its *eapness z a conductor to make x act z a portion ( ! conduct+ l9e4 ,x is p]fectly true t ! e>? is a v poor conductor z comp>$ ) metals4 ,let u say1 = ! sake ( example1 t damp e>? conducts #ajj1jjj times worse ?an copp]4 ,x w be evid5t t if a copp] wire #a_/bj ( an in* 9 section c\ld convey a giv5 electric curr5t1 ! same l5g? ( e>? hav+ a section ( #e1jjj in*es w\ld c>ry ! same curr5t equally well1 & co/ virtually no?+1 beyond ! co/ ( a metal plate1 or sack ( coke1 pres5t+ a squ>e surface ( a little ov] #gj in*es 9 ! side at ea* end ( ! l9e4 ,?is mode ( complet+ ! circuit is kn[n z ! e>? plate4 ,s #ch4 ,! next po9t to be rememb]$ 9 connection ) batt]ies is1 t ! electromotive =ce 7,e4,m4,f47 dep5ds on ! nature ( ! elem5ts 7z9c & silv]1 z9c & c>bon1 etc47 & ! excitants us$ 9 ! cell1 & has absolutely no?+ :atev] to d ) _! size4 ,?is may be lik5$ to diff]5ce ( temp]ature 9 bodies4 ,?us1 :e!r we h a block ( ice z l>ge z an iceb]g or an in* squ>e1 ! temp]ature w nev] exce$ #cb deg4,f4 z long z x rema9s ice2 & :e!r we cause a p9t or a ?\s& gallons ( wat] to boil 7"u ord9>y conditions71 its temp]ature w n exce$ #bab deg4,f4 ,! only means we h ( increas+ ! ,e4,m4,f41 or t5sion1 or pot5tial1 ( any giv5 batt]y1 is by connect+ up its con/itu5t cells 9 s]ies2 t is to say1 connect+ ! c>bon or copp] plate ( ! "o cell to ! z9c ( ! next1 & s on4 ,by ?is means we increase ! ,e4,m4,f4 j 9 ! same degree z we add on cells4 ,! accept$ /&>d = ! measure ( electromotive =ce is call$ a ,,volt1 & #a volt is practically a trifle less ?an ! ,e4,m4,f4 set up by a s+le ,daniell's cell2 ! exact am\nt be+ #a4jgi volt1 or #a-a_/ab volt v ne>ly4 ,! ,e4,m4,f4 ( ! ,leclan*'e is v ne>ly #a4f volt1 or ne>ly #a volt & #b_/c4 ,?us 9 ,fig4 #ae1 :i* illu/rates #c ,leclan*'e cells set up 9 s]ies1 we %\ld get #a4f volt #a4f #a4f --------- #d4h volts z ! total electromotive =ce ( ! comb9ation4 ,illu/ration3 ,fig4 #ae4 ,s #ci4 ,! curr5t1 or amplitude ( ! cont9u\s vibrations kept up 9 ! circuit1 dep5ds ^u two ?+s3 #a/1 ! electromotive =ce2 #bnd1 ! resi/ance 9 ! circuit4 ,!re is a c]ta9 am\nt ( resemblance betwe5 ! fl[ ( wat] "u pressure & electricity 9 ?is respect4 ,let u suppose we h a con/ant head ( wat] at our disposal1 & all[ x to fl[ ?r\gh a tube pres5t+ #a in* ap]ture4 ,we get a c]ta9 def9ite fl[ ( wat]1 let u say #ajj gallons ( wat] p] h\r4 ,m we d n get1 ow+ to ! resi/ance oppos$ by ! n>r[ness ( ! tube to a great] fl[4 ,if n[ we d\ble ! capacity ( ! exit tube1 leav+ ! pressure or head ( wat] ! same1 we %all d\ble ! fl[ ( wat]4 ,or we may arrive at ! same result by d\bl+ ! head or pressure ( wat]1 :i* w !n cause a d\ble quantity ( wat] to fl[ out aga9/ ! same resi/ance 9 ! tube1 or conductor4 ,j 9 ! same way1 if we h a giv5 pressure ( electric /ra91 or ,e4,m4,f41 we c get a great] or less] fl[ or curr5t by hav+ less or m resi/ance 9 ! circuit4 ,! /&>d ( fl[+ curr5t is call$ an ,,amp,e',,re2 & #a ampe're is t curr5t :i*1 9 pass+ ?r\gh a solution ( sulphate ( copp]1 w deposit #ah4ce gra9s ( copp] p] h\r4 ,! unit ( resi/ance is kn[n z an ,,ohm4 ,! resi/ance kn[n z #a ohm is v ne>ly t ( a column ( m]cury #a squ>e millime'tre 7#a_/be ( an in*7 9 section1 & #da-a_/d in*es 9 height2 or #a foot ( ,no4 #da gauge pure copp] wire1 #cc_/ajjjj ( an in* 9 diamet]1 at a temp]ature ( #cb deg4 ,fahr41 or #j deg4 ,c5tigrade4 ,s #dj4 ,pr(essor ,ohm1 :o made a special /udy ( ! relative effects ( ! resi/ance ins]t$ 9 ! circuit1 ! electromotive =ce1 & ! curr5t produc$1 enunciat$ ! foll[+ law1 :i*1 aft] him1 has be5 call$ ,,ohm',s ,,law4 ,x is t if we divide ! numb] ( electromotive =ce units 7volts7 employ$ by ! numb] ( resi/ance units 7ohms7 9 ! entire circuit1 we get ! numb] ( curr5t units 7ampe'res7 fl[+ ?r\gh ! circuit4 ,?is1 express$ z an equation is %[n bel[3 ,e_/,r ,c or ,electromotive =ce_/,resi/ance ,curr5t4 ,or if we l to use ! initials ( volts1 ampe'res1 & ohms1 in/ead ( ! g5]al t]ms1 ,e1 ,r1 & ,c1 we may write ,v_/,r ,a1 or ,volts_/,ohms ,ampe'res4 ,f ?is x appe>s t #a volt w s5d a curr5t ( #a ampe're ?r\gh a total resi/ance ( #a ohm1 s9ce #a divid$ by #a equals #a4 ,s also #a volt c s5d a curr5t ( #d ampe'res ?r\gh a resi/ance ( #a_/d ( an ohm1 s9ce #a divid$ by #a_/d is equal to #d4 ,we c !re=e always d\ble ! curr5t by halv+ ! resi/ance2 or we may obta9 ! same result by d\bl+ ! ,e4,m4,f41 all[+ ! resi/ance to rema9 ! same4 ,9 p]=m+ ?is ) batt]ies we mu/ be> 9 m9d t ! metals1 c>bon1 & liquids 9 a batt]y d !mselves set up resi/ance4 ,?is resi/ance is kn[n z int]nal resi/ance1 & mu/ always be reckon$ 9 ^! calculations4 ,we c halve ! int]nal resi/ance by d\bl+ ! size ( ! negative plate1 or :at am\nts to ! same ?+ by connect+ two simil> cells 9 p>allel2 t is to say1 ) bo? _! z9cs toge!r1 to =m a positive plate ( d\ble size1 & bo? c>bons or copp]s toge!r to =m a s+le negative ( twice ! dim5sions ( t 9 "o cell4 ,any numb] ( cells ?us c\pl$ toge!r 9 p>allel h _! resi/ances r$uc$ j 9 proportion z _! numb] is increas$2 h5ce #h cells1 ea* hav+ a resi/ance ( #a ohm if c\pl$ toge!r 9 p>allel w\ld h a jo9t resi/ance ( #a_/h ohm only4 ,! ,e4,m4,f4 w\ld rema9 ! same1 s9ce ?is does n dep5d on ! size ( ! plate 7see ,s #ch74 ,! arrangem5t ( cells 9 p>allel is %[n at ,fig4 #af1 :]e ?ree ,leclan*'e cells are illu/rat$ ?us c\pl$4 ,! foll[+ little table gives an idea ( ! ,e4,m4,f4 9 volts1 & ! int]nal resi/ance 9 ohms1 ( ! cells mo/ly us$ 9 electric bell "w4 ,illu/ration3 ,fig4 #af4 ,,table ,,%[+ ,e4,m4,f4 ,,& ,r4 ,,( ,,batt]ies4 ---------------------------------------- --------------------------- ,"n ( ,cell4 ,capacity ( ,cell4 ,electromotive ,resi/ance 9 =ce 9 ,volts4 ,ohms4 ---------------------------------------- --------------------------- ,daniell #b qu>ts #a4jgi #a ,gravity #b qu>ts #a4jgi #aj ,leclan*'e #a p9t #a4fj #a4ac #b p9ts #a4fj #a4aj #c p9ts #a4fj #j4hg ,agglom]ate #a p9t #a4ee #j4gj #b p9ts #a4ee #j4fj #c p9ts #a4ee #j4ej ,full] #a qu>t #a4hj #j4ej ---------------------------------------- --------------------------- ,f ?is x is evid5t t if we jo9$ up ! two plates ( a ,full] cell ) a %ort wire pres5t+ no appreciable resi/ance1 we %\ld get a curr5t ( 7#a4hj divid$ by #j4ej7 #c4f ampe'res along ! wire2 :]eas if a gravity ,daniell 7 employ$ ! curr5t fl[+ 9 ! same wire w\ld only be a little ov] #a_/aj ( an ampe're1 s9ce #a4jgi_/aj #j4ajgi4 ,b e wire1 no matt] h[ %ort or h[ ?ick1 pres5ts "s resi/ance2 s we mu/ always take into acc\nt bo? ! int]nal resi/ance 7t ( ! batt]y itself7 & ! ext]nal resi/ance 7t ( ! wires1 etc41 lead+ to ! bells or indicators7 9 reckon+ = any giv5 curr5t f any cell or cells4 ,,*apt] ,,iii4 ,,on ,,electric ,,bells ,,& ,,o!r ,,signall+ ,,appliances4 ,s #da4 ,an electric bell is an arrangem5t ( a cyl9drical s(t iron core1 or cores1 surr\nd$ by coils ( insulat$ copp] wire4 ,on caus+ a curr5t ( electricity to fl[ r\nd ^! coils1 ! iron becomes1 = ! "t be+1 p[]fully magnetic 7see ,s #ac74 ,a piece ( s(t iron 7kn[n z ! armature71 support$ by a spr+1 faces ! magnet ?us produc$4 ,?is armature c>ries at its free extremity a rod ) a bob1 clapp] or hamm]1 :i* /rikes a bell1 or gong1 :5 ! armature1 "u ! influ5ce ( ! pull ( ! magnet1 is drawn t[>ds x4 ,9 connection ) ! armature & clapp] is a device :]eby ! fl[ ( ! curr5t c be rapidly int]rupt$1 s t on ! cessation ( ! curr5t ! iron may lose its magnetism1 & all[ ! spr+ to )draw ! clapp] f aga9/ ! bell4 ,?is device is kn[n z ! contact break] & v>ies some:at 9 design1 accord+ to :e!r ! bell belongs to ! trembl+1 ! s+le /roke1 or ! cont9u\s r++ class4 ,s #db4 ,9 ord] t ! electric bell-fitt] may h an intellig5t conception ( 8 "w1 he %\ld make a small electric bell himself4 ,by s do+1 he w ga9 m practical k ( :at are ! requisites ( a good bell1 & :]e defects may be expect$ 9 any he may be call$ ^u to pur*ase or exam9e1 ?an he c obta9 f pages ( writt5 description4 ,= ?is reason ,i reproduce "h 7) "s trifl+ additions & modifications7 ,mr4 ,g4 ,edw9son's directions = mak+ an electric bell3--#aj ,h[ to make a bell4--,! old me?od ( do+ ?is 0 to take a piece ( r\nd iron1 b5d x into ! =m ( a horse-%oe1 anneal x 7by leav+ x = sev]al h\rs 9 a bright fire1 & all[+ x to cool gradually z ! fire goes out71 w9d on ! wire1 & fix x z a magnet on a /\t bo>d ( bee* or mahogany2 a bell 0 !n screw$ to ano!r "p ( ! bo>d1 a piece ( brass hold+ ! hamm] & spr+ be+ fa/5$ to ano!r "p4 ,_m bells made ^u ?is plan are /ill (f]$ = sale & ex*ange1 b _! p]=mance is always liable to v>iation & ob/ruction1 f ! foll[+ causes3--,to insure a /eady1 uni=m vibratory /roke on ! bell1 its hamm] mu/ be nicely adju/$ to move )9 a /rictly def9$ & limit$ space2 ! lea/ fractional dep>ture f ?is adju/m5t results 9 an unsatisfactory p]=mance ( ! hamm]1 & (t5 a total failure ( ! magnet to move x4 ,9 bells con/ruct$ on ! old plan1 ! wood5 base is liable to expansion & contraction1 v>y+ ) ! *ange ( wea!r & ! humidity1 temp]ature1 etc41 ( ! room 9 :i* ! bells are plac$4 ,?us a damp1 foggy night may cause ! wood to swell & place ! hamm] out ( range ( ! bell1 :ile a dry1 hot day may alt] ! adju/m5t 9 ! opposite direction4 ,su* failures z ^!1 f ! above causes alone1 h (t5 br\ght electric bells into disrepute4 ,be/ made bells are1 !re=e1 n[ made ) metallic 7practically inexpansible7 bases1 & x is ?is k9d ,i recomm5d to my read]s4 ,footnote #aj3 ,amateur ,"w4 ,illu/ration3 ,fig4 #ag4 ,illu/ration3 ,fig4 #ah4 ,! ,base1 to :i* all ! o!r p>ts are fa/5$1 is made ( #c_/d 94 mahogany or teak1 #f 94 by #d 941 %ap$ z %[n at ,fig4 #ag1 ) a smoo? surface & ,fr5* poli%$4 ,to ?is is atta*$ ! metallic base-plate1 :i* may be cut out ( %eet-iron1 or %eet-brass 7?is latt] is bett]1 z iron di/urbs ! action ( ! magnet some:at71 & %ap$ z %[n 9 ,fig4 #ah2 or x may be made ( ca/-iron1 or ca/ 9 brass2 or a sub/itute = x may be made 9 wr\ght-iron1 or brass1 z %[n 9 ,fig4 #ai4 ,i pres5t ^! v>i\s =ms to suit ! v>i$ h&icrafts ( my read]s2 = in/ance1 a work] 9 %eet metal may f9d x m conv5i5t to manufacture 8 bell out ( ! p>ts sket*$ 9 ,figs4 #ag1 #ah1 #bj;,a1 #ba1 #bc1 #bd;,a1 & #be2 b1 on ! o!r h&1 a smi? or eng9e] might pref] ! improv$ =m %[n at ,fig4 #ca1 & select ! p>ts %[n at ,figs4 #bj;,a1 #bb1 #ai1 *oos+ ei!r to =ge ! horse-%oe magnet1 ,fig4 #bj1 or to turn up ! two cores1 z %[n at ,fig4 #ba 7,a71 to screw into ! metal base1 ,fig4 #ba ,b1 or to be fa/5$ by nuts1 z %[n at ,fig4 #ai4 ,! result w be ! same 9 ! end1 if good workman%ip is employ$1 & ! prop] c>e tak5 9 fix+ & adju/+ ! p>ts4 ,a t9-plate work] may ev5 cut 8 base-plate out ( /\t block t91 & get z good results z if ! bell 7 made by an eng9e]4 ,9 "s makes1 ! base-plate is cut or /amp$ out ( ?ick %eet-iron1 9 ! =m %[n by ! dott$ l9es on ,fig4 #ah1 & :5 ?us made1 ! "p ,a is turn$ up at "r angles to =m a bracket = ! magnet cores1 ! opposite projection is cut (f1 & a turn$ brass pill> is ins]t$ at ,b to hold ! contact screw1 or contact break] 7,s #da74 ,illu/ration3 ,fig4 #ai4 ,illu/ration3 ,fig4 #bj4 ,illu/ration3 ,fig4 #bj ,a4 ,! ,magnet may be =m$ z %[n at ,fig4 #bj1 or at ,fig4 #bj;,a4 ,its ess5tial p>ts are3 #a/4 ,two s(t iron cores 79 "s =ms a s+le core is n[ employ$72 #bnd4 ,an iron base1 or yoke1 to hold ! cores toge!r2 #crd4 ,two bobb9s w\nd ) wire4 ,! old =m ( magnet is %[n at ,fig4 #bj4 ,9 ?is =m ! cores & yoke are made out ( "o piece ( metal4 ,a l5g? ( r\nd ,sw$i% iron is b5t r\nd 9 ! %ape ( a horse%oe2 ?is is r5d]$ ?or\ghly s(t by anneal+1 z expla9$ fur!r on4 ,x is absolutely ess5tial t ! iron be v s(t & well anneal$1 o!rwise ! iron cores reta9 a consid]able am\nt ( magnetism :5 ! curr5t is n pass+1 :i* makes ! bell sluggi% 9 action1 & necessitates a high] batt]y p[] to make x "w 7see ,s #ad74 ,two bobb9s ( insulat$ wire are fitt$ on ! cores1 & ! magnet is held 9 its place by a transv]se /rip ( brass or iron secur$ by a wood screw pass+ betwe5 ! two bobb9s4 ,! size ( ! iron1 ! wire1 ! bobb9s1 & ! me?od ( w9d+ is ! same z 9 ! =m next describ$1 ! only diff]5ce be+ t ! l5g? ( ! iron core1 be=e b5d+ to ! horse-%oe =m1 mu/ be su* z to all[ ( ! two /raight portions ( ! legs to be #b 94 9 l5g?1 & /& #a-c_/h ap>t :5 b5t4 ,we may n[ consid] ! con/ruction ( a magnet ( ! =m %[n at ,fig4 #bj;,a4 ,to make ! cores ( su* a magnet1 to r+ a #b-a_/b 94 bell1 get two #b in* l5g?s ( #e_/af 94 be/ ,sw$i% r\nd iron1 /raight5 !m1 smoo? !m 9 a la!1 & r$uce #a_/d 94 ( "o end ( ea* to #d_/af ( an 941 leav+ a %>p %\ld]1 z %[n at ,fig4 #ba ,a4 ,next1 get a #b-;94 l5g? ( angle iron1 drill 9 x two holes #a-c_/h ap>t1 ( ! exact diamet] ( ! turn$ ends ( ! cores1 & rivet ^! securely 9 _! places2 ?is may be done by fa/5+ ! cores or legs 9 a vice :il/ !y are be+ rivett$4 ,two holes %\ld be also bor$ 9 ! o!r flange to receive ! two screws1 :i* are to hold ! magnet to ! base1 z %[n at ,fig4 #ba ,b4 ,! magnet is n[ q equal to ! horse-%oe =m1 & mu/ be made q s(t by anneal+4 ,?is is done by heat+ x 9 a cle> coal fire to a bright r$ heat1 !n bury+ x 9 hot a%es1 & all[+ x to cool gradually = a p]iod ( f #ab to #bd h\rs2 or p]haps a bett] guide to ! process w be to say1 bury ! iron 9 ! hot a%es & leave x !re until bo? x & !y are q cold4 ,! iron mu/ be br\ght to a bright *]ry r$ heat be=e all[+ x to cool1 to s(t5 x prop]ly1 & on no acc\nt mu/ ! cool+ be hurri$1 or ! metal w be h>d4 ,iron is r5d]$ h>d by hamm]+1 by be+ rapidly cool$1 ei!r 9 cold air or wat]1 & h>d iron reta9s magnetism = a long] "t ?an s(t iron4 ,z we wi% to h a magnet t w only act z su* :5 a curr5t ( electricity is pass+ ar\nd x1 & %all return to ! /ate ( a simple piece ( unmagnetis$ iron :5 ! curr5t is brok51 we take ! precaution ( hav+ x ( s(t iron4 ,_m bells h fail$ to act prop]ly1 because ?is precaution has be5 neglect$1 ! residual 7or rema9+7 magnetism hold+ d[n ! armature aft] contact has be5 brok54 ,:5 ! magnet has be5 anneal$1 its legs %\ld be poli%$ ) a piece ( em]y clo?1 & ! ends fil$ up level & smoo?4 ,if x is int5d$ to fa/5 ! cores into ! base-plate1 ?is also %\ld be anneal$1 unless x be made ( brass1 9 :i* case a ?9 /rip ( s(t iron %\ld connect ! back ends ( ! two legs be=e !y are atta*$ to ! brass base 7an iron yoke is pref]able1 z x c]ta9ly is conducive to bett] effects to h a massive iron yoke1 ?an to h a m]e /rip z ! connect+ piece74 ,x w also be readily und]/ood & conc$$ t ! cores %\ld be cut long] :5 !y are to be fa/5$ by nuts1 to all[ a suffici5t l5g? = screw+ ! ends to receive ! nuts4 ,! l5g? & size ( ! legs giv5 above are suitable = a #b-a_/b 94 bell only2 = l>g] bells ! size increases #a_/af ( an in*1 & ! l5g? #a_/d ( an in*1 = e #a_/b 94 increase 9 ! diamet] ( ! bell4 ,illu/ration3 ,fig4 #ba4 ,! ,bobb9s1 on :i* ! wire t s]ves to c>ry ! magnetis+ curr5t is to be w\nd1 next dem& our att5tion4 ,!y may be turn$ out ( boxwood1 ebony1 or ebonite1 or out ( any h>d wood /rong en\gh & d5se en\gh to all[ ( be+ turn$ d[n ?9 9 ! body1 a v necess>y requirem5t to br+ ! convolutions ( wire z ne> ! coil z possible )\t t\*+ x4 ,"s amateurs use ! turn$ ends ( cotton reels or spools1 & glue !m on to a tube ( pap] =m$ on ! cores !mselves4 ,if ?is tube be aft]w>ds well cov]$ ) melt$ p>aff9 wax1 ! plan answ]s admirably1 b ( c\rse ! bobb9s become fixtures on ! magnets4 ,!re are "s p]sons :o are clev] en\gh to make firm bobb9s out ( br[n pap] 7l rocket cases71 ) reel ends1 t c be slipp$ (f & on ! magnet cores4 ,to ^! ,i w\ld say1 by all means at y\r comm&1 d s if y c4 ,! size ( ! bobb9s = a #b-a_/b 94 bell %\ld be3 l5g? #a-c_/d 941 diamet] ( heads #c_/d ( an 941 ! l5g? increas+ #a_/d ( an 94 & ! diamet] #a_/h ( an 94 = e additional #a_/b 94 9 ! diamet] ( ! bell4 ,! holes ?r\gh\t ! bobb9s %\ld be ( a size to fit ! iron cores exactly1 & ! cores %\ld project #a_/h ( an in* above ! end ( ! bobb9s :5 ^! are fitt$ on4 ,! wire to be w\nd on ! bobb9s is sold by all deal]s 9 electrical app>atus4 ,x is copp] wire1 cov]$ ) cotton or ) silk1 to ensure insulation4 ,m5tion has already be5 made ( :at is meant by insulation at ,s #c1 b1 9 ord] to refre% ! read]'s memory1 ,mr4 ,g4 ,edw9son's words are quot$ "h4 ,to insulate1 z und]/ood by electricians1 means to protect f leakage ( ! electric curr5t1 by int]pos+ a bad conductor ( electricity betwe5 two good conductors1 ?us insulat+#aa or deta*+ !m f electric contact4 ,footnote #aa3 ,insula 9 ,lat9 means an isl&1 h5ce an electrifi$ body is said to be insulat$ :5 surr\nd$ by non-conductors1 z an isl& by ! sea4 ,! foll[+ li/ w enable my read]s to see at a glance ! value ( ! sub/ances m5tion$ "h z conductors or insulators1 ! be/ conductors be+ arrang$ f ! top d[nw>ds1 & ! bad conductors or insulators oppos$ to !m 9 simil> ord]1 viz41 ! wor/ conductors or be/ insulators be+ at ! top3-- ,conductors4 ,insulators4 ,silv]4 ,p>aff9 ,wax4 ,copp]4 ,guttap]*a4 ,iron4 ,indi>ubb]4 ,brass4 ,%ellac4 ,all ,o!r ,metals4 ,v>ni%es4 ,metallic ,solutions4 ,seal+ ,wax4 ,metallic ,salts4 ,silk & ,cotton4 ,wet ,/one4 ,dry ,clo?+4 ,wet ,wood4 ,dry ,wood4 ,oil1 ,dirt & ,ru/4 ,see also ! m ext5d$ li/ giv5 at ,s #e = a m complete & exact classification4 ,x w be se51 on ref]5ce to ! above1 t copp] is a good conductor1 be+ excell$ by silv] alone 9 ?is respect2 & t silk & cotton are bad conductors4 ,:51 !re=e1 a copp] wire is b\nd r\nd ) silk or ) cotton1 ev5 if two or m /r&s ( su* a cov]$ wire be sup]impos$1 s9ce ^! are electrically sep>at$ by ! non-conduct+ cov]+1 no escape ( electricity f "o /r& to ! o!r c take place1 & ! /r&s are said to be insulat$4 ,if ! copp] wire _h be5 coil$ nak$ r\nd a bobb91 ea* convolution t\*+ its neighb\r1 ! curr5t w\ld n h circl$ r\nd ! :ole l5g? ( ! coils ( wire1 b w\ld h leapt across f "o coil to ! o!r1 & ?us ! desir$ effect w\ld n h be5 obta9$4 ,a simil> result1 diff]+ only 9 degree1 w\ld occur if a badly insulat+ wire 7 us$1 say "o 9 :i* ! cov]+ _h be5 worn 9 places1 or _h be5 badly w\nd1 s z to expose pat*es ( b>e copp] wire4 ,if ! insulation ( a wire be suspect$1 x %\ld be imm]s$ 9 hot melt$ p>aff9 wax1 & !n hung up to dra9 & cool4 ,! size ( wire to be us$ on a #b-a_/b 94 bell %\ld be ,no4 #bd ,b4 ,w4 ,g41 ! size fall+ two numb]s = ea* #a_/b 94 increase 9 ! diamet] ( ! bell4 ,9 ^! wires ! high] ! numb]1 ! f9] ! size1 ,no4 #f be+ #a_/e & ,no4 #dj be+ #a_/bjj ( an in* 9 diamet]4 ,silk-cov]$ wire has an advantage ov] cotton-cov]$ wire1 inasmu* z ! insulat+ mat]ial occupies less space1 h5ce ! convolutions ( wire lie clos] toge!r4 ,?is is important1 z ! curr5t has less effect on ! iron if remov$ fur!r f x1 ! decrease be+ z ! squ>e ( ! di/ance t ! curr5t is remov$ f ! wire4 ,magnets coil$ ) silk-cov]$ wire admit also ( bett] f9i%1 b = mo/ purposes cotton-cov]$ wire w give satisfaction1 especially if well p>aff9$4 ,?is wire mu/ be w\nd on ! bobb9s1 f end to end regul>ly1 ) ! coils side by side1 z a reel ( cotton is w\nd4 ,?is may be done on a la!1 b a little practice w be necess>y be=e ! inexp]i5c$ h& c guide ! wire 9 a regul> mann]4 ,if1 h[ev]1 ! spool ( wire h a metal rod pass$ up its c5tre1 & ?is be held 9 ! h& at a di/ance ( a foot or m f ! bobb9 on ! la!1 ! wire w almo/ guide itself on1 provid+ ! guid+ h& be all[$ to foll[ its c\rse4 ,) a little c>e1 ! wire = ^! little magnets may be w\nd entirely by h&4 ,be=e comm5c+ to w9d on ! bobb9s1 j measure (f #h 94 ( ! wire 7n cutt+ x (f7 & coil ?is l5g? ar\nd a p5cil1 to =m a small coil or helix4 ,! p5cil may !n be )drawn f ! helix ?us =m$1 :i* s]ves to connect ! wire ) "o ( ! po9ts ( contact4 ,?is free end is to be fa/5$ outside ! bobb9 by a nick 9 ! head2 or ! #a_/h 94 l5g?1 be=e be+ =m$ into a helix1 may be pu%$ ?r\gh a small hole made on ! head ( ! bobb91 s t #h 94 project outside ! bobb91 :i* project+ piece may be coil$ into a helix z above describ$4 ,! wire %\ld n[ be w\nd exactly z a reel ( cotton is w\nd1 9 close coils f end to end1 & !n back aga91 until ?ree lay]s ( wire h be5 laid on1 s t ! coil+ f9i%es at ! opposite end to t at :i* x began4 ,to prev5t ?is uncoil+1 x %\ld be fa/5$ by ty+ d[n tightly ) a turn or two ( /rong silk4 ,! wire %\ld n[ be cut f ! hank1 leav+ ab\t #b 94 ( free wire project+ at ! f9i%+ end ( ea* bobb94 ,9 cases :]e _m bobb9s h to be w\nd1 ei!r = bells1 = relays1 or = indicator coils1 a device simil> to t illu/rat$ at ,fig4 #ba ,a may be employ$4 ,?is electric bobb9 w9d] consi/s 9 a table :i* c be /ood on a la! or ne> any o!r driv+ :eel4 ,two c>ri]s1 ,c ,c1 some:at simil> to ! back c5tre & poppet head ( a la!1 holl[ inside1 & furni%$ ) a spr+ & slid+ pi/on sp9dle1 /& "o at ea* end ( ?is table4 ,! slid+ sp9dle ( ! "o c>ries at its extremity a pulley1 ,a1 by means ( :i* motion c be transmitt$ f ! b& ( ! driv+ :eel4 ,! slid+ sp9dles1 ,b ,b1 are fitt$ ) recesses & screws1 ,h ,h ,h ,h1 by means ( :i* ! tempor>y wood5 cores1 or ! p]man5t iron cores1 ( ! bobb9s c be held :ile ! bobb9s are be+ w\nd4 ,! bobb9 is plac$ z %[n at ,d2 a flat piece ( metal1 ,e1 h+$ at ,g1 presses aga9/ ! bobb91 ow+ to ! spr+ ,f4 ,! c5tre figure %[s details ( ! c>ri]1 ,c1 9 section4 ,at ! bottom is %[n ! spool ( wire on a /&>d ,l4 ,! wire passes f ?is spot betwe5 ! two indi>ubb] roll]s1 ,m ,m1 on to ! bobb9 ,d4 ,illu/ration3 ,fig4 #ba ,a4 ,:5 ! bobb9s h be5 w\nd1 !y may be slipp$ ov] ! magnet cores4 ,!y %\ld fit pretty tightly2 if !y d n1 a roll ( pap] may be put r\nd ! magnet cores1 to ensure _! n slipp+ :5 ! bell is at "w4 ,! helix ends ( ! bobb9s %\ld /& upp]mo/1 z %[n at ,fig4 #bb ,a4 ,a %ort l5g? ( ! l[] free ends ( wire 7ne> ! base or yoke7 %\ld n[ be b>$ ( _! cov]+1 clean$ ) em]y pap]1 twi/$ toge!r tightly1 z %[n at ,fig4 #bb ,b1 sold]$ toge!r1 & any excess ( wire cut (f ) a %>p pair ( pli]s4 ,to prev5t any *ance electrical leakage betwe5 ?is b>$ portion ( ! wire & ! iron1 x %\ld be c>efully coat$ ) a little melt$ guttap]*a1 or ,pr\t's electric glue4 ,illu/ration3 ,fig4 #bb4 ,( c\rse1 if ! op]ator has any skill at w9d+1 he may w9d bo? bobb9s ) "o cont9u\s l5g? ( wire1 ?us avoid+ jo9s1 tak+ c>e t ! direction ( ! w9d+ 9 ! f9i%$ coils be z %[n at ,fig4 #bb ,b2 t is to say1 t ! wire f ! "u side ( "o bobb91 %\ld pass ov] to ! next 9 ! same way z ! curls ( ! lett] rotat$ ,s4 ,illu/ration3 ,fig4 #bc4 ,illu/ration3 ,fig4 #bd4 ,illu/ration3 ,fig4 #be4 ,illu/ration3 ,fig4 #bf4 ,illu/ration3 ,fig4 #bg4 ,! "p t next claims our consid]ation is ! armature1 ) its fitt+s4 ,! armature is made out ( #e_/af squ>e b> iron1 ( ! be/ quality1 s(t1 & well anneal$1 & fil$ up smoo? & true4 ,! proportionate l5g? is %[n at ,figs4 #bc & #bd2 & ! size ( ! iron = o!r bells is regulat$ 9 ! same ratio z t ( ! cores4 ,two me?ods ( mak+ & atta*+ ! spr+s & hamm]s are %[n4 ,fig4 #bd %[s ! section ( an armature fitt$ ) back spr+ & contact spr+ 9 "o piece4 ,?is is cut out ( h>d %eet-brass1 z wide z ! armature1 fil$ or hamm]$ d[n to ! desir$ degree ( spr+9ess1 !n fil$ up true on ! edges4 ,x may be atta*$ to ! iron ( ! armature1 ei!r by sold]+1 by rivett+1 or by means ( two small screws4 ,rivett+ is1 p]haps1 ! be/ mode1 z x is n liable to %ake loose by ! vibration ( ! hamm]4 ,! spr+ at its %ank end may be screw$ or rivett$ to ! bracket4 ,mr4 ,edw9son consid]s ?is ! bett] =m ( contact spr+4 ,! o!r =m is made 9 two pieces1 z %[n at ,fig4 #bc1 :]e two /rips ( h>d brass are cut (f1 ( ! wid? ( ! armature1 & ! edges fil$4 ,a slot is !n cut 9 ! back end ( ! armature to receive ! two brass /rips1 & ^! are sold]$ into x4 ,! top /rip is !n b5t back ov] ! armature to =m ! contact-spr+1 ! o!r /rip be+ sold]$ or rivett$ to a small bracket ( angle brass4 ,9 ei!r case a %ort rod ( /\t h>d brass wire is rivett$ or screw$ into ! free end ( ! armature1 & to ! end ( ?is rod is screw$ or sold]$ ! metal bead1 or bob1 :i* =ms ! hamm] or clapp] ( ! bell4 ,! next portion to be made is ! contact pill>1 or bracket1 ) its screw1 z %[n at ,fig4 #be4 ,?is may ei!r be a %ort /\t pill> ( #a_/d 94 brass rod1 ab\t #a 94 high1 tapp$ on "o side to receive ! screw1 :i* %\ld be fitt$ ) a back nut2 or x may1 z %[n 9 ! figure1 be made out ( a /\t piece ( angle brass4 ,! exact size & l5g? ( ! screw is immat]ial2 x mu/1 h[ev]1 be long en\gh to rea* 7:5 put 9 its place beh9d ! contact spr+7 ! spr+ itself1 & /ill h a few ?reads beh9d ! back nut to sp>e4 ,! screw %\ld be nicely fitt$ to ! pill>1 & ! lock nut %\ld cl5* x well1 z :5 once ! adju/m5t ( ! p>ts is f\nd :i* gives good r++1 x is advisable t no motion %\ld take place1 le/ ! p]fection ( r++ be int]f]$ )4 ,"s mak]s use a set screw at ! side ( ! pill> :]e) to hold ! contact screw2 o!rs split ! pill> & spr+ x aga9/ ! contact screw2 b1 all ?+s consid]$1 ! back nut gives ! greate/ satisfaction4 ,:5 ! bell is 9 action1 a t9y sp>k is produc$ at e make & break ( contact betwe5 ! contact spr+ & ?is screw4 ,?is sp>k soon corrodes ! end ( ! screw & ! back ( ! spr+ if brass alone is us$1 z ?is latt] ru/s "u ! influ5ce ( ! sp>k4 ,to prev5t ?is1 a piece ( plat9um mu/ be sold]$ or rivett$ to ! spr+1 at ! po9t :]e ! screw t\*es1 z %[n at ,fig4 #bf1 & also at ! extremity ( ! contact screw itself4 ,x is bett] to rivet ! plat9um ?an to sold] x1 z ! plat9um is v apt to absorb ! sold]1 9 :i* case x ru/s quickly1 & ! goodness ( ! contact is soon spoil$1 :5 ! bell ceases to r+4 ,to rivet ! plat9um piece on to ! spr+1 z %[n at ,fig4 #bf1 x is only ne$ful to procure a %ort l5g? ( ,no4 #af plat9um wire1 say #a_/h 941 !n1 hav+ drill$ a correspond+ hole at ! desir$ spot 9 ! contact spr+1 put ! plat9um wire half way ?r\gh ! hole1 & give x "o or two %>p bl[s on an anvil1 ) a smoo? 7p5$7 hamm]4 ,illu/ration3 ,fig4 #bh4 ,illu/ration3 ,fig4 #bi4 ,?is w at once rivet x 9 its place1 & spread x suffici5tly to make a good surface = contact4 ,! screw mu/ likewise be tipp$ ) plat9um1 by hav+ a small hole bor$ 9 ! c5tre ( its extremity1 ( ! same diamet] z ! plat9um wire1 :i* mu/ !n be pu%$ 91 & rivett$ by hamm]+ ! end1 & burr+ ! sides ( ! screw4 ,:i*ev] me?od be adopt$1 c>e mu/ be tak5 t ! plat9um tip on ! screw & ! speck on ! contact spr+ are adju/$ s z to t\* exactly 9 _! c5tres4 ,x w be h>dly wor? :ile = ! amateur to ca/ or ev5 turn up 8 own bells 7:i* are g5]ally ( ! class kn[n z clock gongs71 z ^! c n[ be procur$ s *eaply already nickell$ 7see ,fig4 #bh74 ,! bell mu/ be adju/$ on its pill> 7see ,fig4 #bi;,a71 :i* is itself screw$ into a hole 9 ! base-plate1 :]e x is held by a nut4 ,! adju/m5t ( ! bell is effect$ by plac+ x ov] ! %\ld] ( ! pill>1 & !n cl5*+ x d[n by screw+ ov] x "o or o!r ( ! nuts %[n at ,fig4 #bi4 ,! bell %\ld cle> ! base1 & %\ld be at su* a height z to be /ruck on its edge by ! hamm] or clapp] atta*$ to ! armature1 ,figs4 #bc & #bd4 ,we /ill ne$1 to complete our bell1 two b9d+ screws1 :i* may take ei!r ( ! =ms %[n at ,fig4 #bg2 & an insulat+ wa%]1 or coll>1 made ( ebonite or boxwood1 soak$ 9 melt$ p>aff91 to prev5t ! contact pill> 7,fig4 #be7 mak+ electrical contact ) ! metal base4 ,! be/ %ape to be giv5 to ^! wa%]s is %[n at ,fig4 #cj4 ,!y consi/ 9 two ?9 circlets ( wood or ebonite1 t w j n meet :5 dropp$1 "o on ! "o side1 & "o on ! o!r ( ! hole ?r\gh :i* ! %ank ( ! contact pill> passes :5 set up on ! base-plate4 ,if a wood5 base be us$ bel[ ! metal base-plate1 !n only "o wa%]1 or coll>1 ne$ be us$--t is1 ! "o above--s9ce ! screw ( ! pill> w pass into ! wood1 & ?is is n a conductor4 ,if ! metal base alone be us$1 bo? wa%]s mu/ be employ$1 & a small nut 7n s l>ge z ! wa%]7 us$ to tight5 up & hold ! pill> firm & immovable 9 its place opposite ! contact spr+4 ,illu/ration3 ,fig4 #cj4 ,hav+ n[ all ! p>ts at h&1 we c proce$ to fit !m toge!r1 :i* is done z foll[s3--,! bell pill>1 ) its bell atta*$1 is fa/5$ by its %ank into ! hole %[n ne> ,b1 ,fig4 #ag1 :]e x is screw$ up tight by ! squ>e nut %[n at ,fig4 #bi c4 ,9 ! same mann]1 we mu/ fa/5 ! contact pill>1 or bracket1 %[n at ,fig4 #bd ,a4 ,:i*ev] =m be us$1 we mu/ take great c>e t x be insulat$ f metallic contact ) ! metal base-plate by wa%]s1 z %[n at ,fig4 #cj 7simil> wa%]s mu/ be us$ = ! two b9d+ screws if ! :ole base-plate be made 9 metal74 ,?is be+ done1 ! metal frame1 ,fig4 #ah1 is put 9 position on ! wood5 base1 z %[n at ,fig4 #ag1 & screw$ d[n !reto by ! screws indicat$ at s s s4 ,! magnet may !n be screw$ d[n to ! metal frame z %[n4 ,! small bracket ( angle brass m>k$ ,b1 9 ,figs4 #bc & #bd1 is next screw$ into its place2 t is1 9 su* a position t ! armature /&s squ>ely fac+ ! poles ( ! electro-magnet1 b n q t\*+ !m 7say #a_/af ( an in* = a #b-a_/b 94 bell74 ,9 sett+ up ?is & ! contact pill>1 ! greate/ c>e mu/ be tak5 t ! plat9um tip ( ! contact screw1 ,fig4 #be1 %\ld t\* lightly ! c5tre ( ! plat9um speck at ! back ( ! spr+1 ,figs4 #bc & #bd1 %[n full size at ,fig4 #bf4 ,! free ends ( ! helically coil$ electro-magnet wires %\ld n[ be ins]t$ into %ort l5g?s ( small indi>ubb] tub+ 7same z us$ = fe$+ bottles71 ! extremities be+ drawn ?r\gh & #a 94 ( ! copp] wire b>$ ( its cov]+ = ! purpose ( mak+ good metallic contact ) ! connections4 ,"o ( ^! ends is to be sold]$1 or o!rwise metallically connect$1 to ! angle brass c>ry+ ! armature1 spr+ & clapp]1 ! o!r be+ simil>ly connect$ ) ! left-h& b9d+-screw1 %[n at ,fig4 #ag4 ,ano!r %ort l5g? ( wire 7also enclos$ 9 rubb] tub+7 mu/ be arrang$ to connect ! contact screw pill> ,fig4 #ag1 ) ! "r-h& b9d+-screw4 ,:5 ?is has be5 done1 we may proce$ to te/ ! work+ ( ! bell by connect+ up ! b9d+ screws ) ! wires proce$+ f a fre%ly-*>g$ ,leclan*'e cell4 ,if all h be5 prop]ly done1 & ! connections duly made1 ! armature %\ld beg9 to vibrate at once1 caus+ ! bob1 or hamm]1 to /rike ! bell rapidly2 t is1 provid$ ! plat9um tipp$ screw t\*es ! plat9um speck on ! contact spr+4 ,%\ld ?is n be ! case1 ! screw mu/ be turn$ until ! plat9um tip t\*es ! plat9um speck4 ,! armature w n[ beg9 to vibrate4 ,x may be t ! clapp] runs too ne> ! bell1 s t x gives a h>%1 ?uddy buzz in/ead ( a cle>1 r++ s\nd2 or1 possibly1 ! clapp] is set too f> f ! bell to /rike x4 ,9 ei!r case a little b5d+ ( ! brass wire c>ry+ ! clapp] 7ei!r f or t[>ds ! bell1 z ! case may dictate7 w rem$y ! defect4 ,x is also possible t ! armature itself may h be5 set too ne>1 or too f> f ! electro-magnet4 ,9 ! latt] case1 ! clapp] w n vibrate /rongly en\gh1 9 ! =m] ! vibration w be too %ort1 & ! clapp] may ev5 /ick to ! poles ( ! electros1 especially if ^! h n be5 c>efully anneal$4 ,a little b5d+ ( ! spr+1 to or f ! magnets1 w rem$y ^! defici5cies1 unless ! di/ance be v mu* too great1 9 :i* case ! b5d+ ( ! spr+ w\ld take ! plat9um tip out ( ! c5tre ( ! plat9um speck4 ,illu/ration3 ,fig4 #ca4 ,s #dc4 ,hav+ ?us con/ruct$ an effici5t electric bell we may proce$ to /udy its action & notice "s ( ! defects to :i* x may be subject4 ,9 ! fir/ place1 if we connect up ! bell ) ! batt]y z %[n 9 ,fig4 #ag1 viz41 ! left-h& b9d+-screw ) ! wire proce$+ f ! c>bon ( ! ,leclan*'e1 & ! "r-h& screw ) ! wire f ! z9c1 !n1 if ! plat9um tipp$ screw t\*es ! plat9um speck1 at ! back ( ! contact spr+1 a curr5t ( electricity fl[s f ! left-h& b9d+-screw all r\nd ! coils ( ! electro-magnets1 passes along ! contact spr+ & plat9um speck1 !nce to ! plat9um tipp$ screw along ! %ort l5g? ( wire to ! "r-h& b9d+-screw1 :5ce x returns to ! z9c elem5t ( ! batt]y1 ?us complet+ ! circuit4 ,! curr5t1 9 ?us pass+ ar\nd ! electro-magnet cores1 conv]ts !m1 pro tem41 into a p[]ful magnet 7see ,s #ac72 consequ5tly1 ! armature1 ) its contact spr+ & hamm]1 is pull$ t[>ds ! electro-magnets & at ! same "t gives a bl[ to ! bell4 ,n[1 if in/ead ( hav+ ! plat9um speck atta*$ to a flexible spr+1 x _h be5 atta*$ bodily to ! rigid iron armature1 directly ! electro-magnets felt ! influ5ce ( ! curr5t1 ! plat9um speck w\ld h also be5 pull$ out ( contact ) ! plat9um screw1 !re=e ! electro-magnet cores w\ld h imm$iately lo/ _! magnetism 7see ,s #ac1 la/ five l9es74 ,?is w\ld h be5 disadvantage\s1 = two reasons3 #a/1 because ! /roke ( ! hamm] w\ld h be5 v %ort1 & consequ5tly ! r+ ( ! bell v weak2 &1 #bnd1 because1 z ev5 ! s(te/ iron requires "s appreciable "t = ! electric curr5t to fl[ r\nd x to magnetise x to its full capacity1 x w\ld ne$ a mu* great] batt]y p[] to produce a giv5 /roke1 if ! contact 7 s v %ort4 ,! use ( an ela/ic contact spr+ is1 !re=e1 j to l5g!n ! "t ( contact4 ,b ! electro-magnets1 ev5 :5 ! flexible spr+ is us$1 d actually pull ! plat9um speck out ( contact ) ! plat9um screw4 ,:5 ?is takes place1 ! circuit is brok51 & no m curr5t c fl[ r\nd ! electro-magnets1 ! spr+ reass]ts its p[]1 & ! contact is aga9 made betwe5 ! contact screw & contact spr+1 to be aga9 rapidly brok51 ea* break & make contact be+ accompani$ by a correspond+ly rapid vibration ( ! armature1 ) its att5dant clapp]1 :i* ?us sets up t *>act]i/ic rapid r++ :i* has e>n$ = ^! bells ! "n ( trembl+1 *att]+1 or vibrat+ bells4 ,s #dd4 ,f a c>eful consid]ation ( ! la/ two sections x w be evid5t t ! possible defects ( electric bells may be class$ "u f\r heads3 viz41 #a/1 ,bad contacts2 #bnd1 ,bad adju/m5t ( ! p>ts2 #crd1 ,defective insulation2 #d?1 ,w>page or %r9kage ( base4 ,we w consid] ^! 9 ! above ord]4 ,fir/ly1 !n1 z to bad contacts4 ,_m op]ators are cont5t ) simply turn+ ! t]m9al wires r\nd ! base ( ! b9d+-screws4 ,unless ! b9d+-screws are firmly held d[n on to ! wires by means ( a back nut1 a great loss is sure to occur at ^! po9ts1 z ! wires may h be5 put on ) sweaty h&s1 :5 a film ( oxide soon =ms1 :i* greatly l[]s ! conductivity ( ! junction4 ,aga91 at ! junction po9ts ( ! wires ) ! contact angle brass & contact pill>1 "s workm5 sold] ! junctions1 us+ kill$ spirits z a flux4 ,a sold]$ contact is c]ta9ly ! be/1 electrically speak+1 b kill$ spirits1 or *loride ( z9c1 %\ld nev] be us$ z a flux 9 any app>atus or at any po9t t _c be wa%$ 9 abundance ( wat]1 z *loride ( z9c is v deliquesc5t 7runs to wat]71 rott5s ! wire1 & spoils ! insulation ( ! adjac5t p>ts4 ,if sold] be us$ at any p>ts1 let res9 be us$ z a flux4 ,ev5 if any excess ( res9 rema9 on ! "w1 x does no h>m & does n de/roy ! insulation ( any ( ! o!r portions4 ,ano!r po9t :]e bad contact may arise is at ! plat9um contacts4 ,plat9um is a metal :i* does n ru/ easily1 ev5 "u ! influ5ce ( ! electric sp>k giv5 at ! po9t ( contact4 ,!re=e1 x is pref]r$ to e o!r metal 7except1 p]haps1 iridium7 = contact break]s4 ,plat9um is an exp5sive metal1 ! retail price be+ ab\t #cjs4 an ounce1 & z x is ne>ly twice z heavy z lead 7,lead #aa4 ,plat9um #ba4e7 v little goes to an ounce4 ,= *eap bells1 !re=e1 !re is a great temptation to use "s o!r :ite metal1 su* z silv]1 g]man silv]1 plat9oid1 etc4 ,! tip ( ! plat9um screw may be te/$ = its be+ v]itably plat9um 9 ! foll[+ mode3 ,t\* ! tip ) ! /opp] ( a bottle conta9+ aqua=tis1 s z to leave a t9y drop on ! extreme po9t ( ! suspect$ plat9um4 ,if x boils up gre51 or turns black1 x is n plat9um2 if x rema9s unalt]$1 x may be silv] or plat9um4 ,aft] x has /ood on ! tip = a m9ute1 draw x along a piece ( :ite pap]1 s z to produce a /reak ( ! acid4 ,expose ! pap] = a few m9utes to sunlight4 ,if ! /reak turns violet or p9ky violet1 ! metal is silv]2 if ! pap] simply %[s a slightly yell[i% /reak1 ! metal is plat9um4 ,! tip ( ! plat9um screw mu/ be c>efully dri$ & clean$ aft] ?is trial be=e be+ replac$4 ,secondly1 z to bad adju/m5t4 ,x is evid5t t ! magnets & ! armature mu/ /& at a c]ta9 di/ance ap>t to give ! be/ effects ) a giv5 batt]y p[]4 ,! di/ance v>ies f #a_/bd 94 9 ! v smalle/1 to #a_/h 94 9 l>ge bells4 ,sometimes 7b only 9 v badly made in/rum5ts7 ! armature adh]es to ! poles ( ! electro-magnet4 ,?is is due to residual magnetism 7see ,s #ad71 & po9ts to h>d or unanneal$ iron 9 ! cores or armature4 ,z a make-%ift1 ?is defect may be p>tially rem$i$ by pa/+ a ?9 piece ( pap] ov] t surface ( ! armature :i* faces ! poles ( ! electro-magnets4 ,ano!r bad adju/m5t is :5 ! plat9um screw does n t\* fairly on ! c5tre ( ! plat9um speck1 b t\*es ! spr+ or ! sold]4 ,ru/ is !n sure to =m1 :i* de/roys ! goodness ( ! contact4 ,to adju/ ! contact spr+ at ! "r di/ance f ! plat9um screw1 hold ! hamm] aga9/ ! bell or gong4 ,! armature %\ld n[ j n t\* ! poles ( ! electro-magnet4 ,n[ screw up ! plat9um screw until x cle>s ! contact spr+ by ab\t ! ?ickness ( a %eet ( br[n pap] 7say #a_/ej ( an in*74 ,let ! hamm] g1 & notice :e!r ! contact spr+ makes good contact ) ! plat9um screw4 ,?is may be tri$ by ! ,leclan*'e cell z well1 s z to make sure ( ! "* ( ! r++4 ,:5 ?is has be5 satisfactorily adju/$ ! back-nut or set screw may be tight5$1 to insure t ! vibration ( ! hamm] %all n alt] ! adju/m5t4 ,x sometimes happ5s t ! spr+ t be>s ! armature is itself ei!r too /rong 7or set back too f>7 or too weak4 ,9 ! =m] case1 ! electro-magnet _c pull ! armature ) suffici5t =ce to give a good bl[2 9 ! latt]1 ! spr+ _c return ! armature1 ) its att5dant contact spr+1 back to its place aga9/ ! plat9um screw4 ,to asc]ta9 :i* ( ^! two defects obta9s1 x is only necess>y1 :ile ! bell is 9 action1 to press ! spr+ lightly ) a bit ( wire1 fir/ t[>ds & !n away f ! electro-magnets4 ,if ! r++ is improv$ 9 ! fir/ case1 ! spr+ is too /rong2 if improvem5t takes place 9 ! latt] case1 ! spr+ is too weak4 ,! ?ird s\rce ( ineffici5t action1 defective insulation1 is n likely to occur 9 a newly-made bell1 except by gross c>elessness4 ,/ill1 x may be well to po9t out :]e electrical leakage is likely to occur1 & h[ its pres5ce may be asc]ta9$1 localiz$1 & rem$i$4 ,if ! wire us$ to w9d ! electro-magnet be old1 badly cov]$1 or b>$ 9 sev]al places 9 w9d+1 x probably w all[ ! curr5t to %ort circuit1 in/ead ( trav]s+ ! :ole l5g? ( ! coils4 ,if ?is be ! case1 ! magnet w be v weak3 ! magnet ( a #b-a_/b-;94 bell %\ld be able to su/a9 easily a #a lb4 weight atta*$ by a piece ( /r+ to a smoo? piece ( #a_/b-;94 squ>e iron plac$ across its poles1 :5 en]giz$ by a s+le p9t ,leclan*'e cell4 ,if x w n d ?is1 ! insulation may be suspect$4 ,if ! wire has be5 w\nd on ! b>e cores 7)\t bobb9s71 z is sometimes done1 b>$ places 9 ! wire may be t\*+ ! iron4 ,?is may be asc]ta9$ by connect+ "o pole ( a bottle bi*romate1 or o!r p[]ful batt]y1 ) "o ( ! wires ( ! electro-magnet coils1 & draw+ ! o!r pole ( ! batt]y across ! clean iron faces ( ! electro-magnet poles4 ,if !re is any leakage1 sp>ks w appe> on mak+ & break+ contact4 ,no?+ b unw9d+ & rew9d+ ) a well cov]$ wire c rem$y ^! defects4 ,! o!r po9ts :]e ! insulation may be defective are betwe5 ! b9d+ screws & ! base1 if ?is be all ( metal2 or betwe5 ! contact spr+ block & ! base1 & ! contact pill>4 ,x is also probable 7if ! connect+ wires h n be5 cov]$ ) indi>ubb] tub+1 z recomm5d$7 t leakage may be tak+ place betwe5 ^! wires & "s portion ( ! metal "w ( ! base or frame4 ,?is mu/ be c>efully exam9$1 & if any po9t ( contact be obs]v$1 a little piece ( ,pr\t's ela/ic glue1 previ\sly heat$1 mu/ be ins]t$ at ! suspect$ places4 ,) reg>d to ! b9d+ screws1 if !y /& on ! wood5 base1 _! insulation 7unless ! base be v damp inde$7 w be suffici5tly good2 b if ! base is entirely metallic1 !n ebonite or boxwood wa%]s mu/ be us$ to insulate !m f contact ) ! base-plate4 ,) reg>d to ! contact spr+ block & ! plat9um screw pill>1 x is p]missible t "o or ! o!r %\ld n be insulat$ f ! base or frame2 b "o or ! o!r mu/ be insulat$ by means ( ebonite or o!r insulat+ wa%]s4 ,p]sonally1 ,i pref] to insulate bo?2 b 9 _m really good bells only ! plat9um screw pill> is ?us insulat$4 ,any su* leakage c be imm$iately detect$ by hold+ "o pole ( a p[]ful batt]y aga9/ ! suspect$ b9d+-screw1 or block1 or pill>1 & :ile 9 ?is position1 draw+ ! o!r pole across "s b>e iron portion ( ! frame or metal base4 ,sp>ks w appe> if !re is any leakage4 ,! f\r? defect--t is1 w>page or %r9kage ( ! base--c only occur 9 badly-made bells1 9 :i* ! entire base is ( wood4 ,a cursory exam9ation w %[ :e!r ! bo>d is w>p$ or swoll51 or :e!r x has %runk4 ,w>p+ or swell+ w ?r[ ! electro-magnet too f> f ! armature1 or set ! pill> out ( place2 %r9kage1 on ! contr>y1 w br+ ! p>ts too close toge!r & jamb ! magnets1 ! armature1 & ! contact pill> into an unworkable position4 ,s #de4 ,be=e quitt+ ! subject ( ! defects ( bells1 x may n be out ( place to m5tion t no bell t is set to d real "w %\ld be fitt$ up )\t a cov] or case4 ,! du/ :i* is sure to accumulate1 n to speak ( damp & fumes1 etc41 w c]ta9ly militate aga9/ good contacts & good action if ?is important po9t be neglect$4 ,! cov] or case g5]ally takes ! =m ( a %all[ box1 z %[n at ,fig4 #cb1 & may be made f #a_/d-;94 teak1 mahogany1 or walnut1 dovetail$ toge!r & well poli%$4 ,x is fa/5$ to ! base 9 ! same mann] z ! sides ( a ,dut* clock1 by means ( /uds1 hooks & eyes4 ,at ! bottom ( ! box is cut a slot1 ( suffici5t wid? & l5g? to admit ! play ( ! hamm] %ank4 ,illu/ration3 ,fig4 #cb4 ,9 ! annex$ table is giv5 a g5]al idea ( ! proportion :i* %\ld be obs]v$ 9 ! con/ruction ( bells ( diff]5t sizes4 ,x mu/ be not$ t if ! bells are to be us$ at long di/ances f ! batt]y1 r m ( a f9] gauge ( wire mu/ be employ$ to w9d ! magnets ?an t h]e9 recomm5d$1 unless1 inde$1 relays be us$ 9 conjunction ) ! bells4 ,s #df4-- ,,table ,%[+ proportions to be obs]v$ 9 ! diff]5t p>ts ( electric bells4 ---------------------------------------- --------------- ,diamet] ,l5g? (,diamet] ,l5g? ,diamet] ,b4 ,w4 ,g4 ( ,magnet ( ,magnet ( ( ,bobb9 ( ,wire ,bell4 ,cores4 ,cores4 ,bobb94 ,head4 on ,bobb94 ---------------------------------------- --------------- #b-a_/b #b #e_/af #a-c_/d #c_/d #bd #c #b-a_/d #c_/h #b #g_/h #bd #c-a_/b #b-a_/b #g_/af #b-a_/d #a #bb #d #b-c_/d #a_/b #b-a_/b #a-a_/h #bb #d-a_/b #c #i_/af #b-c_/d #a-a_/d #bj #e #c-a_/d #e_/h #c #a-c_/h #ah #e-a_/b #c-a_/b #aa_/af #c-a_/d #a-a_/b #af #f #c-c_/d #c_/d #c-a_/b #a-e_/h #af #f-a_/b #d #ac_/af #c-c_/d #a-c_/d #af #g #d-a_/d #g_/h #d #a-g_/h #af #g-a_/b #d-a_/b #ae_/af #d-a_/d #b #ad #h #d-c_/d #a #d-a_/b #b-a_/h #ad #h-a_/b #e #a-a_/af #d-c_/d #b-a_/d #ad #i #e-a_/d #a-a_/h #e #b-c_/h #ad #i-a_/b #e-a_/b #a-c_/af #e-a_/d #b-a_/b #ad #aj #e-c_/d #a-a_/d #e-a_/b #b-e_/h #ad #aj-a_/b #f #a-e_/af #e-c_/d #b-c_/d #ab #aa #f-a_/d #a-c_/h #f #b-g_/h #ab #aa-a_/b #f-a_/b #a-g_/af #f-a_/d #c #aj #ab #f-c_/d #a-a_/b #f-a_/b #c-a_/h #aj ---------------------------------------- --------------- ,illu/ration3 ,fig4 #cc ,a4 ,illu/ration3 ,fig4 #cc ,b4 ,illu/ration3 ,fig4 #cd4 ,s #dg4 ,we c n[ glance at sev]al modifications 9 ! %ape & mode ( action ( electric bells & _! cong5]s4 ,tak+ ,figs4 #cc ,a & ,b z our typical =ms ( trembl+ bell1 ! fir/ notable modification is "o by means ( :i* ! bell is made to give a s+le /roke only1 = ea* contact ) ! batt]y4 ,?is =m1 :i* is kn[n z ! s+le /roke bell1 l5ds itself to ^? cases 9 :i* x may be requir$ to transmit preconc]t$ signals2 z also :]e x is desir$ to place _m bells 9 "o circuit4 ,fig4 #cd illu/rates ! con/ruction ( ! s+le /roke bell4 ,x diff]s f ! trembl+ bell 9 ! mode 9 :i* ! electro-magnet is connect$ up to ! b9d+ screws4 ,9 ! trembl+ bell1 ,fig4 #cc1 ! circuit is complet$ ?r\gh ! plat9um screw pill>1 to ! b9d+ screw m>k$ ,z1 h5ce ! circuit is rapidly made & brok5 z long z by any means contact is made ) ! batt]y1 & ! b9d+ screws ,l & ,z4 ,b 9 ! s+le /roke bell1 ,fig4 #cd1 ! wires f ! electro-magnet are connect$ directly to ! two b9d+ screws ,l & ,z1 s t :5 contact is made ) ! batt]y1 ! armature is drawn to ! poles ( ! electro-magnet1 & kept !re s long z ! batt]y curr5t passes4 ,by ?is means1 only "o /roke or bl[ is giv5 to ! bell = ea* contact ( ! batt]y4 ,( c\rse1 directly ! connection ) ! batt]y is brok51 ! spr+ :i* c>ries ! armature & clapp] flies back ready to be aga9 attract$1 %\ld connection aga9 be made ) ! batt]y4 ,to regulate ! di/ance ( ! armature f ! poles ( ! electro-magnets1 a set screw ,q takes ! place ( ! plat9um screw 9 ! ord9>y =m1 :ile to prev5t ! hamm] rema9+ 9 contact ) ! bell 7:i* w\ld produce a dull ?ud & /op ! cle> r+ ( ! bell71 a /op 7g7 is set ne> ! end ( ! armature1 or two /uds are fix$ on ! tips ( ! poles ( ! electro-magnets4 ,! mode ( adju/+ ?is k9d ( bell1 s z to obta9 ! be/ effect1 diff]s a little f t employ$ 9 ! case ( ! trembl+ bell4 ,! armature mu/ be press$ t[>ds ! poles ( ! electro-magnets1 until x re/s aga9/ ! /op or /uds4 ,a piece ( wood or cork may be plac$ betwe5 ! armature & ! set screw ,q1 to reta9 ! armature 9 ?is position1 :ile ! rod c>ry+ ! hamm] or clapp] is be+ b5t 7if requir$7 until ! hamm] j cle>s ! bell4 ,if x t\*es ! bell1 a ?ud in/ead ( a r+ is ! result2 if x is set (f too f>1 ! r+ w be too weak4 ,! armature c n[ be releas$1 by remov+ ! wood or cork1 & ! set screw ,q driv5 =w>ds or backw>ds until ! be/ effect is produc$ :5 te/$ ) ! batt]y4 ,! t5sion ( ! armature spr+ mu/ be c>efully look$ to 9 ^! s+le /roke bells4 ,if x is too /rong1 ! bl[ w be weak2 if too weak1 ! hamm] trembles1 s t a cle> s+le /roke is n obta9able1 z ! spr+ *att]s4 ,s #dh4 ,! cont9u\s r++ bell is ! modification :i* next dem&s our att5tion4 ,9 ?is1 ! r++ action1 :5 once />t$ by ! pu%1#ab or o!r contact mak]1 hav+ be5 t\*$1 cont9ues ei!r until ! batt]y is exhau/$1 or until x is /opp$ by ! p]son 9 *>ge4 ,! great use ( ?is arrangem5t is self-evid5t 9 cases ( burgl> al>ms1 wat*man's al>ms1 etc41 z ! cont9u\s r++ gives notice t ! call has n receiv$ att5tion4 ,! cont9u\s r++ bell diff]s b little f ! ord9>y trembl+ bell4 ,! *ief diff]5ce lies 9 ! addition ( an automatic device :]eby contact is kept up ) ! batt]y1 ev5 aft] ! pu% contact has ceas$4 ,z x is desirable = ! p]son 9 *>ge to be able to /op ! r++ at w1 )\t proce$+ to ! place :]e ! pu% /&s1 s x is n usual to make ! cont9u\s r++ arrangem5t dep5d5t on ! pu%1 ?\gh1 ( c\rse1 ?is c\ld be done1 by caus+ x to engage 9 a cat*1 :i* w\ld keep up ! contact1 :5 once made4 ,cont9u\s r++ bells may be conv5i5tly divid$ into two classes2 viz41 #a/1 ^? 9 :i* a device is atta*$ to ! framework ( ! bell2 :i* device1 :5 once upset by ! fir/ /roke ( ! bell1 places ! bell 9 direct communication ) ! batt]y indep5d5t ( ! pu% or usual contact2 & #bndly1 ^? 9 :i* a sep>ate device is us$1 = ! same purpose4 ,?is latt] arrangem5t admits ( ! use ( an ord9>y trembl+ bell4 ,footnote #ab3 ,a pu%1 ( :i* sev]al =ms w h]eaft] be describ$ & figur$1 consi/s ess5tially 9 a spr+ c>ry+ a /ud1 /&+ directly ov]1 b n t\*+1 ano!r /ud1 fix$ to a base4 ,! l[] /ud is connect$ to "o t]m9al ( batt]y1 ! spr+ is connect$ to ! bell4 ,:5 ! spr+ is press$ d[n1 ! two /uds come into contact1 ! curr5t fl[s1 & ! bell r+s4 ,illu/ration3 ,fig4 #ce4 ,illu/ration3 ,fig4 #cf4 ,fig4 #ce illu/rates ! action ( bells ( ! fir/ class4 ,9 ! fir/ place x w be notic$ t !re are ?ree b9d+ screws in/ead ( two1 z 9 ! ord9>y patt]n1 "o m>k$ ,c connect$ z usual ) ! c>bon elem5t ( ! batt]y2 ano!r m>k$ ,l1 :i* connects ) l9e wire1 & a ?ird1 ,z1 connect$ by means ( a bran* wire 7%unt wire71 proce$+ f ! z9c ( ! batt]y4 ,x w be se51 t if ! batt]y curr5t is by means ( ! pu% caus$ to fl[ ?r\gh ! coils ( ! electro-magnets1 ! armature is attract$ z usual by !m1 & 9 mov+ t[>ds !m1 releases & lets fall ! lev] contact1 :i*1 re/+ on ! contact screw1 completes ! circuit betwe5 ,z & ,c1 s t ! bell is 9 direct communication ) its batt]y1 indep5d5tly ( ! pu%4 ,h5ce ! bell cont9ues r++1 until ! lev] is replac$4 ,?is c be done1 ei!r by pull+ a *eck /r+ 7l a bell-pull7 atta*$ to an eye 9 ! lev]1 or by means ( a press-button & c\nt]-spr+2 z %[n 9 ,fig4 #cf1 ,a & ,b4 ,illu/ration3 ,fig4 #cg4 ,illu/ration3 ,fig4 #ch4 ,illu/ration3 ,fig4 #ci4 ,9 cont9u\s r++ bells ( ! second class1 a det5t simil> to t %[n at ,fig4 #ce ,d is us$1 b ?is1 in/ead ( be+ actuat$ by ! electro-magnet belong+ to ! bell itself1 is controll$ by a sep>ate & entirely indep5d5t electro-magnet1 :i*1 z x may be w\nd ) _m coils ( f9e wire1 & h a specially light spr+ = ! armature1 c be made v s5sitive4 ,?is second electro-magnet1 :i* s]ves only to make contact ) a batt]y1 is kn[n z a ,relay1 & is ext5sively employ$ 9 _m cases :]e x is desir$ to put "o or m batt]ies into1 or out ( circuit1 f a di/ance4 ,! relay may be look$ ^u z an automatic h&1 :i* c be made to repeat at a di/ant po9t contacts made or brok5 by h& at a ne>] "o4 ,fig4 #cg %[s ?is arrangem5t1 atta*$ to ! same base bo>d z ! bell itself4 ,on contact be+ made ) ! pu%1 ! curr5t ent]s at ,c1 circulates r\nd ! cores ( ! relay1 ?us conv]t+ x into a magnet4 ,! armature a is !reby pull$ to ! magnet1 & 9 s do+ releases ! det5t lev]1 :i* falls on ! contact screw1 ?us at "o & ! same "t break+ ! circuit ?r\gh ! relay1 & mak+ ! circuit ?r\gh ! bell magnets ,b ,b'1 back to ! batt]y by ,z4 ,a second modification ( ?is mode ( caus+ an ord9>y bell to r+ cont9u\sly is %[n at ,fig4 #ch1 ! peculi> =m ( relay us$ !re) be+ illu/rat$ at ,fig4 #ci4 ,"h1 ! relay is plac$ on a sep>ate base bo>d ( its own1 & c\ld1 if necess>y1 be ?r[n out ( circuit altoge!r1 by means ( a swit*1#ac s t ! bell c be us$ z an ord9>y bell or cont9u\s action at w4 ,x w be notic$ t ! relay has 9 ?is sket* only "o core4 ,b ! delicacy ( ! action is n impair$ !reby1 z ! armature1 by means ( ! /eel spr+ s1 is made to =m "p & p>cel ( ! magnet1 s t x becomes magnetis$ z well z ! core1 & is attract$ ) m =ce ?an x w\ld be1 if x 7 magnetically insulat$4 ,! batt]y curr5t ent]s by ! wires ,c & ,w1 passes r\nd ! coils ( ! electro-magnet1 & returns by ,z4 ,9 s do+ x en]gises ! electro-magnet ,e1 :i* imm$iately attracts its armature ,a4 ,! =w>d movem5t ( ! armature ,a1 releases ! pivot$ arm ,l1 to :i* is atta*$ a plat9um-tipp$ contact prong ,p4 ,?is1 x w be notic$1 is 9 metallic connection ) ! pill> ,p'1 & ) ! base1 &1 !re=e1 ?r\gh ! wire ,w1 ) ! batt]y4 ,:5 ! arm ,l falls1 ! contact prong completes ! circuit to ! bell1 ?r\gh ! insulat$ pill> ,x4 ,! relay is ?us ?r[n out ( ! circuit at ! same "t t ! bell is ?r[n 94 ,a device simil> to ^? illu/rat$ at ,fig4 #cf c be employ$ to reset ! arm ,l4 ,footnote #ac3 ,describ$ at ,s #fa4 ,illu/ration3 ,fig4 #dj4 ,a r m complicat$ arrangem5t = cont9u\s bell r++ is %[n at ,fig4 #dj4 ,x is kn[n z ,call['s1 & is peculi>ly adapt$ to r++ sev]al bells f "o atta*m5t1 etc4 ,ow+ to ! relay 9 ?is =m be+ w\nd ) two sets ( wires1 x takes a little m batt]y p[]2 b ?is disadvantage is comp5sat$ by its _m good po9ts4 ,! foll[+ description1 tak5 f ,f4 ,c4 ,allsop's pap]s 9 ! ,engli% ,me*anic1 w r5d] ! work+ ( ,call['s atta*m5t p]fectly cle>4 ,:5 ! button ( ! pu% ,p is press$1 ! curr5t 9 ! ma9 circuit fl[s f ! positive pole ,c ( ! batt]y ,d ?r\gh ! relay coil a1 & !nce by ! wire d & pu% ,p1 to ! z9c ( ! batt]y4 ,?is attracts ! armature ,a ( ! relay ,r1 clos+ ! local bell circuit1 ! curr5t fl[+ f ,c ( ! batt]y to armature ,a ( ! relay ,r1 ?r\gh contact po/ p1 t]m9al ,l ( ! bell1 ?r\gh bell to t]m9al ,z1 & !nce by ! wire g to ! z9c ( ! batt]y4 ,"p ( ! curr5t also fl[s along ! wire f ! bell t]m9al ,l ?r\gh ! relay coil b & swit* ,w1 to t]m9al ,z ( ! bell1 ?us keep+ ! armature ( ! relay d[n1 aft] ! ma9 circuit 7?r\gh ! pu%7 has be5 brok52 ! bell cont9u+ to r+ until ! %unt circuit is brok5 by mov+ ! arm ( ! swit* ,w ov] to ! opposite 7or non-contact7 side4 ,! bell c also be /opp$ by %ort circuit+ ! relay1 :i* c be effect$ by an ord9>y pu%4 ,x w be se5 t m ?an "o bell c be rung f ! same atta*m5t1 & ! bell c1 by mov+ ! arm ( ! swit* ,w1 be made cont9u\s r++ or n1 at w4 ,if ! arm ( ! swit* is mov$ ov] to ! opposite side to :i* x is %[n 9 ! figure1 ! %unt circuit ( ! bell ?r\gh ! relay is brok51 & ! bell w r+ only s long z ! button ( ! pu% is kept 94 ,?is cont9u\s arrangem5t is v conv5i5t = front doors1 etc41 :]e tr\ble is exp]i5c$ 9 secur+ imm$iate att5tion to ! summons4 ,in/ead ( be+ tak5 to ! swit*1 z 9 ,fig4 #dj1 ! two wires are tak5 to a contact piece fix$ on ! side ( ! door frame1 & s arrang$ t :5 ! door is op5$1 x ei!r %ort circuits or breaks ! %unt circuit3 ?us :5 ! pu% is press$1 ! bell r+s until ! door is op5$1 ! cont9ual r++ ( ! bell insur+ prompt att5tion4 ,mr4 ,h4 ,?orpe1 ( #ei1 ,!obald's ,road1 ,london1 has devis$ a v +5i\s arrangem5t = ! cont9u\s r++ ( "o or m bells = a /at$ p]iod ( "t4 ,?is is %[n at ,fig4 #dj ,a4 ,x is set 9 action by pull+ ! r+ outside ! bottom ( ! core4 ,! bell or bells !n />t r++1 z contact is e/abli%$ & kept up4 ,! novelty lies 9 ! fact t ! duration ( ! contact1 & consequ5tly ( ! r++1 c be accurately tim$ f #e seconds to #cj seconds1 by m]ely ins]t+ a p9 at diff]5t holes 9 ! rod1 z %[n4 ,aft] ! bells h rung ! requir$ "t ! in/rum5t automatically resets itself4 ,illu/ration3 ,fig4 #dj ,a4 ,s #di4 ,! modifications we are n[ ab\t to consid]1 diff] f ! ord9>y bell1 ei!r 9 ! %ape or mat]ial ( ! bell itself1 ! relative disposition ( ! p>ts1 or "s /ructural detail2 b n ^u ! introduction ( any new pr9ciple4 ,! mo/ /rik+ is c]ta9ly ! ,j5s5 bell1 :i* is %[n 9 section at ,fig4 #da4 ,illu/ration3 ,fig4 #da4 ,accord+ to ,mr4 ,j5s5's sy/em ( electric bells1 ! bell may take any desir$ =m1 t ( ! ord9>y *ur* bell be+ pref]r$1 & ! electro-magnetic app>atus is plac$ entirely inside ! bell itself4 ,to atta9 ?is end ! electro-magnetic app>atus mu/ be compact 9 =m4 ,a s+le electro-magnet has pole pieces at ea* end opposite to :i* an armature is susp5d$ f a pivot & balanc$ by ! hamm] ( ! bell4 ,at ! back ( ! armature !re may be a make & break arrangem5t1 :]eby a cont9u\s succession ( /rokes is effect$1 or ?is may be omitt$1 9 :i* case a s+le /roke is giv5 :5 ! contact ) ! batt]y is made1 or bo? may be effect$ by sep>ate wires1 make contact ) "o wire1 & a s+le /roke is /ruck2 make x ) ! o!r & ! curr5t passes ?r\gh ! make & break & a succession ( /rokes is he>d4 ,:5 ! contact-break] is us$1 x is s arrang$ t a slight rub is caus$ at e /roke1 s keep+ ! contact clean4 ,! flexible break1 ) ! +5i\s wip+ contact1 is a great improvem5t ov] ! ord9>y screw1 :i* (t5 becomes dis>rang$4 ,! =m ( ! magnet is su* t a consid]able degree ( magnetic =ce is caus$ by a comp>atively small batt]y p[]4 ,! electro-magnetic app>atus be+ )9 ! bell ! latt] =ms a v effective & h&some %ield = ! =m]4 ,n only c ! bell %ield ! electro-magnet f wet b ! :ole ( ! conduct+ wires z well4 ,! bell may be screw$ to a tube ?r\gh :i* passes ! conduct+ wire1 :i* makes contact ) an insulat$ metallic piece 9 ! c5tre ( ! top ( ! bell4 ,bo? ! wire & ! contact piece are z completely %ield$ f ! wea!r z if )9 ! bell itself4 ,illu/ration3 ,fig4 #db4 ,! great po9t ( dep>ture is ! disc>d+ ( ! unsightly magnet box1 & ! hemisph]ical bell 7see ,fig4 #cb71 & sub/itut+ a bell ( ! ,*ur* type 7see ,fig4 #db71 & plac+ inside x an electro-magnet specially arrang$4 ,! inv5tors use a s+le sol5oidal magnet ( a peculi> con/ruction1 by :i* ! armature is attract$ by bo? poles simultane\sly4 ,by ?is means less ?an half ! usual quantity ( wire is requir$1 ?us r$uc+ ! ext]nal resi/ance ( ! circuit "o half4 ,moreov] ! armature1 besides be+ magnetis$ by induction1 z act$ on 9 ! ord9>y me?od ( mak+ electric bells1 is by ,messrs4 ,j5s5's plan directly pol>is$ by be+ 9 actual magnetic contact by ! connection ( ! gimbal 7:i* is "o piece ) ! armature7 ) ! core iron ( _! magnet4 ,x is ?us induc$ to p]=m ! l>ge/ am\nt ( "w ) ! smalle/ electro-motive =ce4 ,in/ead ( ! armature & clapp] be+ 9 a /raight l9e atta*$ to a rigid spr+1 :i* necessitates a consid]able attractive p[] to prim>ily give x mom5tum1 9 ! ,j5s5 ,bell ! armature & hamm] are 9 ! =m ( an inv]t$ ,u1 & be+ p]fectly balanc$ f ! po9t ( susp5sion1 ! l9es ( =ce f a comp>atively small magnetic field suffice to set ?is improv$ =m ( armature into in/ant regul> vibration4 ,by us+ a flexible break & make arrangem5t in/ead ( ! usual armature spr+ & set screw 7at be/ ( mo/ unc]ta9 action71 x is f\nd t a mu* bett] result is atta9$1 & by ?is device ! armature c be set mu* ne>] ! poles ( ! magnet ) suffici5t trav]se ( ! hamm]4 ,?is is 9 /rict accordance ) ! law ( inv]se squ>es1 :i* holds t ! =ce ex]t$ betwe5 two magnetic poles is inv]sely proportionate to ! squ>e ( ! di/ance betwe5 !m1 or1 9 o!r words1 t magnets increase proportionately 9 _! p[] ( attraction z !y decrease 9 ! squ>e ( ! di/ance4 ,x w n[ be se5 :y ^! bells require s little batt]y p[] to r+ !m3 fir/ly1 ! armature & hamm] are s p]fectly balanc$ z to (f] b little resi/ance2 secondly1 ! ext]nal resi/ance to ! curr5t is r$uc$2 & ?irdly1 ! be/ possible use is made ( ! electro-magnetic =ce at disposal4 ,s #ej4 ,! next modification :i* dem&s att5tion is ! s-call$ ,circul> bell4 ,?is diff]s f ! ord9>y =m only 9 hav+ ! action entirely cov]$ by ! dome4 ,except1 p]haps1 9 po9t ( appe>ance1 ?is pres5ts no advantages to t4 ,! bells kn[n z ,m9+ bells resemble some:at 9 outw>d appe>ance ! circul> bell2 b 9 ^! m9+ bells ! action is all enclos$ 9 /rong1 squ>e teak cases1 to protect ! movem5t1 z f> z possible1 f ! effects ( ! damp4 ,all ! p>ts are1 = ! same reason1 made v l>ge & /rong2 ! armature is pivot$ in/ead ( be+ support$ on a spr+1 ! hamm] %ank be+ long1 & furni%$ ) a heavy bob4 ,! domes or bells are f #f in*es to #ab in*es 9 diamet]1 & are g5]ally fitt$ ) s+le /roke movem5t1 s z to enable !m to be us$ = signall+4 ,! hamm] %ank1 ) its bob1 & ! dome1 :i* /&s 9 ! c5tre ( ! case1 are ! only p>ts left uncov]$1 z may be se5 on ref]5ce to ,figs4 #dc ,a & ,b1 :]e ! ext]ior & int]ior ( su* a bell are %[n4 ,illu/ration3 ,fig4 #dc ,a4 ,illu/ration3 ,fig4 #dc ,b4 ,illu/ration3 ,fig #dd4 ,s #ea4 ,9 ! ,electric ,trumpet1 introduc$ by ,messrs4 ,b9swang]1 ( ! ,g5]al ,electric ,company1 we h a v novel & effective arrangem5t ( ! p>ts ( an electric bell & telephone toge!r4 ,?is in/rum5t1 along ) its batt]y1 l9e & pu%1 is illu/rat$ at ,fig4 #dd1 :]e ,a is a holl[ brass cyl9d]1 9 :i* is plac$ an ord9>y electro-magnet simil> to ,figs4 #bj or #bj ,a4 ,at ! front end1 ne> ,b1 is affix$ by its edges a ?9 disc ( %eet iron1 precisely z 9 ! ,bell telephone1#ad & ov] aga9/ x1 at ,b1 is an insulat$ contact screw1 z 9 ! ord9>y trembl+ bell4 ,on ! disc ( %eet iron1 at ! spot :]e ! screw t\*es1 is sold]$ a speck ( plat9um4 ,! wires f ! electro-magnet are connect$1 "o to ! upp] b9d+ screw1 ! o!r to ! brass case ( ! in/rum5t itself1 :i* is 9 metallic communication ) ! %eet iron disc4 ,! return wire f ! contact screw is %[n atta*$ to ! insulat$ piece1 & is fa/5$ to ano!r b9d+ screw 7n visible7 on ! base bo>d4 ,:5 contact is made ) ! batt]y1 ?r\gh ! press or pu%1 ! magnet becomes en]gis$1 & pulls ! iron disc or diaphragm t[>ds x1 caus+ x to buckle inw>ds4 ,9 do+ ?is1 contact is brok5 ) ! screw ,b2 consequ5tly ! diaphragm aga9 /raight5s out1 z ! magnet no long] pulls x4 ,aga9 contact is made2 :5 ( c\rse ! same r\nd ( p]=mances is cont9u\sly repeat$4 ,z ! plate or diaphragm vibrates _m hundr$s ( times p] second1 x sets up a di/9ctly musical & l\d s\nd wave1 n unlike ! note ( a cornet-a-pi/on1 or a l\d h>monium re$4 ,) a numb] ( ^! trumpets1 ea* diaphragm be+ duly tun$ to its prop] pit*1 x w\ld be possible to con/ruct a novel musical in/rum5t1 work+ solely by electricity4 ,! pu%es ne$ only take ! =m ( pian(orte keys to r5d] ! in/rum5t )9 ! grasp ( any pian(orte or organ play]4 ,footnote #ad3 ,see ,electrical ,in/rum5t ,mak+ = ,amateurs4 ,:ittak] ,co4 ,second edition4 ,s #eb4 ,sometimes ! gong or dome ( ! ord9>y bell is replac$ by a coil spr+1 z 9 ! ,am]ican clocks2 sometimes qua9t =ms are giv5 to ! p>ts cov]+ ! movem5t1 s z to imitate ! head ( an owl1 etc4 ,b bells ) ^! *anges 9 outw>d =m w n pres5t any difficulty1 ei!r 9 fix+ or 9 managem5t1 to ^? :o h ma/]$ ! /ructural & work+ details giv5 9 ?is *apt]4 ,,*apt] ,,iv4 ,,on ,,contacts1 ,,pu%es1 ,,swit*es1 ,,keys1 ,,al>ms1 ,,& ,,relays4 ,s #ec4 ,all ! appliances :i* h hi!rto be5 describ$1 w\ld be utt]ly useless = ! purposes int5d$1 _h we n at h& "s means ( easily1 c]ta9ly & rapidly complet+ & break+ ! circuit betwe5 ! bell or bells1 on ! "o h&1 & ! batt]y on ! o!r4 ,?is necess>y piece ( app>atus1 :i* is simply a contact mak]1 receives diff]5t names1 dep5d5t on its application4 ,:5 x is int5d$ to be actuat$ directly by h&1 x is kn[n z a pu%1 a pressel1 or pull1 accord+ to ! mode 9 :i* ! contact is made4 ,at ,fig4 #de1 ,a1 ,b1 ,c1 ,d1 & ,e1 %[ ! outw>d =ms ( v>i\s pu%es1 9 wood & *9a1 z s5t out by ! lead+ mak]s4 7,! ones figur$ are f ,messrs4 ,b9swang] ,co47 ,at ,f is a sectional view ( "o ( ^! pu%es1 & ,g %[s ! int]ior :5 ! cov] has be5 remov$4 ,f ^! two latt] illu/rations x w be easily und]/ood t ! pu% consi/s ess5tially 9 two pieces ( metal "o or bo? ( :i* are spr+s1 & "o ( :i* is connect$ ) "o ( ! wires f ! batt]y1 :ile ! o!r is atta*$ to ! wire proce$+ to ! bell4 ,:5 ! button is press$ ! upp] spr+ comes into contact ) ! l[] metal spr+ or plate4 ,! circuit is n[ complete2 h5ce ! bell r+s4 ,b z soon z ! f+] is remov$ f ! /ud or button ( ! pu%1 ! spr+ returns to its old place1 contact be+ !reby brok5 :5 ! bell ceases to r+1 unless x be fitt$ ) a cont9u\s r++ arrangem5t 7see ,s #dh74 ,9 fa/5+ ! lead+ wires to ^! pu%es1 c>e mu/ be tak5 t ! ends ( ! wires be scrap$1 & s& pap]$ q clean & bright1 b5t into a loop :i* mu/ be ins]t$ "u ! head ( ! screw t holds ! wire to ! spr+ pieces2 ! screws be+ !n tight5$ up c>efully to ensure a good grip & contact ) ! wires4 ,illu/ration3 ,fig4 #de4 ,illu/ration3 ,fig4 #df4 ,s #ed4 ,a pressel 7,fig4 #df7 is simply a pu% :i* in/ead ( be+ made a fixture by be+ fa/5$ 9 ! wall or door1 is atta*$ to a metallic wir$ l9e1 s t x is g5]ally made to resemble some:at 9 outw>d appe>ance ! knob or tassel ( ! bell-pull ( ! la/ g5]ation1 ! int]ior arrangem5t is precisely simil> to t ( ! pu%2 t is to say1 ! pressel consi/s 9 a pe>-%ap$ or acorn-%ap$ holl[ wood5 box1 ) a project+ knob or button bel[4 ,?is button is atta*$ to a spr+1 ! t5sion ( :i* keeps ! knob protrud+ f ! end ( ! box1 & at ! same "t prev5ts contacts ) ! second spr+ at ! bottom ( ! box4 ,two insulat$ wires1 "o f ! batt]y1 ! o!r f ! bell1 are connect$ to sep>ate screws at ! top ( ! pressel4 ,"o ( ^! screws connects ) ! l[] spr+1 ! o!r ) ! upp]4 ,illu/ration3 ,fig4 #dg4 ,s #ee4 ,! pull 7,fig4 #dg71 z its "n implies1 makes contact & r+s ! bell on be+ pull$4 ,! knob has a r long %ank b>1 ar\nd :i* is coil$ a pretty /iff spr+4 ,at ! f>!r extremity is an ebonite or boxwood coll> end+ 9 a r wid] metal r+4 ,! wires f ! bell & batt]y are connect$ respectively to two flat spr+s1 a a'1 by ! screws b b'4 ,:5 ! knob is pull$1 ! metal coll> t\*es bo? spr+s1 & ! circuit is complet$4 ,closely alli$ to ! pull is a =m ( b$room contact1 :i* comb9es pe>-pu% or pressel & pull 9 "o device4 ,?is w be readily und]/ood on ref]5ce to ,fig4 #dh4 ,ano!r =m ( b$room pull1 ) ord9>y rope & tassel1 consi/s 9 a box conta9+ a jo9t$ metal lev]1 /&+ ov] a /ud1 f :i* x is kept out ( contact by a c\nt] spr+4 ,to ! project+ end ( ! lev] is atta*$ ! bell rope4 ,:5 ?is is pull$ ! lev] t\*es ! /ud1 contact is made1 & ! bell r+s4 ,?is is cle>ly %[n 9 ,fig4 #di ,a4 ,9 all ^! contacts1 except ! door pull 7,fig4 #dg7 :]e ! friction ( ! action ( pull+ keeps ! surfaces bright1 ! po9ts ( contact %\ld be tipp$ ) plat9um4 ,ano!r =m ( contact to be let 9 ! floor ( ! d9+-room1 )9 easy rea* ( ! foot ( ! c>v]1 or o!r p]sons at ! head ( ! table1 is %[n at ,fig4 #di ,b4 ,illu/ration3 ,fig4 #dh4 ,illu/ration3 ,fig4 #di ,a4 ,illu/ration3 ,fig4 #di ,b4 ,mr4 ,mack5zie has introduc$ a v +5i\s contrivance :]eby ! r+] may "k :e!r ! bell at ! di/ant end has rung4 ,?is is effect$ by inclos+ 9 ! pu% a device simil> to t %[n at ,fig4 #dc ,a4 ,t is to say1 an electro-magnet w\nd ) wire1 & surm\nt$ by a ?9 iron disc1 is plac$ 9 circuit ) ! l9e wires4 ,! r++ ( ! bell rapidly magnetises & demagnetises ! electro-magnet1 & causes a humm+ s\nd1 :i* cle>ly indicates :e!r ! bell is r++ or n4 ,z ?is device c be made v small1 compact1 & n liable to d]angem5t1 x is ( easy application4 ,s #ef4 ,! next =m ( contact to :i* our att5tion mu/ be direct$1 is t kn[n z ! burgl> al>m1 ) its v>iant ( door-contacts1 sa%-contacts1 till-contacts1 etc4 ,! burgl>'s pe/ 7z ! contrivance we illu/rate is call$7 is "o ( ! mo/ useful applications ( electricity = ! protection ( prop]ty aga9/ ?ieves4 ,x consi/s usually1 fir/1 ( a brass plate 7,fig4 #ej71 ^u :i* a plat9um contact piece is fix$1 & second1 ( a spr+ made ( h>d5$ brass or /eel insulat$ f ! plate2 or ( a cyl9drical box ) a spiral spr+ inside 7see ,fig4 #ea74 ,x is s arrang$ t z long z ! /ud is kept press$ 91 ! plat9um po9ts ( contact are kept ap>t2 ?is is ! position :5 fix$ 9 ! rebate ( a clos$ door or w9d[2 b z soon z op5$1 ! /ud passes outw>d ?r\gh ! hole1 & ! po9ts ( contact come toge!r & complete ! circuit ( ! wires 9 connection ) ! bell4 ,! bell is be/ to be a cont9u\s r++ "o4 ,x may be fix$ 9 ! ma/]'s b$room1 or outside ! premises 9 ! /reet4 ,illu/ration3 ,fig4 #ej4 ,illu/ration3 ,fig4 #ea4 ,legge's ,w9d[ ,bl9d contact is an arrangem5t by :i* ! bl9d is secur$ at ! bottom by atta*+ x to a hook or button4 ,a slight pressure aga9/ ! bl9d 7caus$ by anyone try+ to ent] aft] hav+ brok5 a w9d[7 sets ! electric bell 9 motion unkn[n to ! intrud]4 ,illu/ration3 ,fig4 #eb4 ,illu/ration3 ,fig4 #ec4 ,a =m ( floor contact1 :i* may be plac$ "u a light mat or c>pet1 illu/rat$ at ,fig4 #eb1 s]ves to give notice if anyone be wait+ at ! door1 or /epp+ into places :i* are desir$ to be kept private4 ,all ^! arrangem5ts1 to be s]viceable1 %\ld be connect$ ) cont9u\s r++ bells 7see ,s #dh74 ,:]ev] x is likely t ^! arrangem5ts may /& a long "t )\t be+ call$ into play1 x is bett] to employ "s =m ( contact 9 :i* a rubb+ action 7:i* t5ds to clean ! surfaces & !n make a good contact7 is br\ght into play1 r ?an a m]ely dott+ action4 ,= ?is reason1 spr+ contacts 9 :i* ! spr+s connect$ ) ! wires are kept ap>t by an insulat+ w$ge 7%[n at ,fig4 #ec7 z long z ! door or w9d[ are kept clos$1 are pref]r$4 ,9 ! case ( w9d[s1 /rips ( brass let into ! frame on ea* side ( ! sa%1 are ?r[n into contact by ! spr+s a & a' 9 ! sa% itself1 z %[n at ,fig4 #ed4 ,= %op doors & o!rs1 :]e a %ort contact only is requir$1 & ?is only :5 ! door is op5$1 a contact su* z %[n at ,fig4 #ee is well adapt$4 ,x consi/s1 z w be se51 9 a peculi>ly %ap$ pivot$ trigg] a1 :i* is lift$ =w>ds :5 ! door is op5$1 s t x makes contact ) ! spr+ b4 ,ow+ to ! curv$ %ape ( ! arm ( ! trigg]1 ! contact is n repeat$ :5 ! door is clos$4 ,illu/ration3 ,fig4 #ed4 ,illu/ration3 ,fig4 #ee4 ,s #eg4 ,9 all =ms ( burgl> or ?ief al>ms1 ! ord9>y sy/em ( hav+ ! circuit brok51 until contact is made by ! intrud] involunt>ily mak+ contact at "s po9t1 pres5ts "o great disadvantage2 & t is1 t if notre ami l'ennemi1 viz41 ! ?ief or burgl>1 be any?+ ( an electrician 7& alas6 to :at base uses may n ev5 sci5ce be p]v]t$7 he w beg9 by cutt+ all suspici\s-look+ wires be=e he attempts to set ab\t any s]i\s "w4 ,?is disadvantage may be entirely ov]come by ! adoption ( a simple modification1 kn[n z ! clos$ circuit sy/em ( bell r++4 ,= ?is ! bells1 etc41 are cont9u\sly 9 contact ) ! batt]ies1 b ow+ to ! peculi> connections1 d n r+ unless ! circuit is brok54 ,to r5d] ! work+ ( su* a sy/em cle> to my read]s1 ,i quote ! description giv5 9 ! ,engli% ,me*anic1 by "o ( our lead+ electricians3-- ,writ+ on ! subject ( ,clos$ ,circuit ,bell-r++1 ,mr4 ,p]r5 ,maycock says3--,?is is pr9cipally adopt$ = al>m purposes4 ,its sup]iority ov] ! op5 circuit sy/em lies 9 ! fact t notice is giv5 on op5+ 7break+7 ! circuit1 :i* is ! rev]se to ! usual practice4 ,9 ! ord9>y me?od x becomes necess>y to h a contact mak]1 diff]+ 9 =m = v>i\s purposes & situations1 :i*1 along ) ! lead+ wires1 mu/ be artfully conceal$4 ,all ?is entails great exp5se2 besides :i* "o c nev] be sure t ! contacts & wires are 9 prop] ord] )\t actually try+ ea* "o4 ,on ! o!r h&1 ) ! clos$ circuit sy/em1 "o has m]ely to place ! wire 9 any conv5i5t position1 x be+ bett] se5 ?an hidd54 ,! v fact t al>m is giv5 on break+ ! contact r5d]s ! me?od applicable 9 circum/ances & "u conditions :i* w\ld r5d] ! op5 me?od difficult & exp5sive1 if n impossible4 ,"o c always be c]ta9 t ev]y?+ is 9 ord]4 ,! mod]n burgl>1 electrically educat$ z reg>ds common practise 9 su* matt]s1 w\ld naturally make a po9t ( cutt+ all wires t fall 9 8 pa?4 ,f ^! & o!r obvi\s consid]ations1 x is evid5t h[ simple & yet h[ p]fect a means ( protection su* a sy/em provides4 ,i w n[ proce$ to expla9 ! mann] ( application4 ,! bell us$ diff]s f ! ord9>y1 only 9 ! arrangem5t ( its ext]nal connections4 ,illu/ration3 ,fig4 #ef ,a4 ,fig4 #ef ,a repres5ts a s+le-al>m circuit4 ,:5 contact is brok5 ext]nally1 !re is a clos$ circuit 9 :i* are ! batt]y & bell magnet coils4 ,consequ5tly ! armature is drawn away f ! contact /ud1 close up to ! electro-magnet1 & is held s4 ,:5 a break occurs1 ! armature flies back1 completes ! local circuit1 & r+s s long z ! ext]nal circuit rema9s brok54 ,!re is a swit* = use :5 ! al>m is n requir$4 ,illu/ration3 ,fig4 #ef ,b4 ,illu/ration3 ,fig4 #eg4 ,fig4 #ef ,b repres5ts a case 9 :i* notice is giv5 at two places4 ,by insulat+ a key z %[n1 reply signall+ c be c>ri$ on betwe5 ! po9ts at :i* ! bells are plac$4 ,a special gravity ,daniell modification 7,s #be7 is us$ = ?is class ( "w 7,fig4 #eg73 a n>r[ lead cyl9d]1 ab\t #b 9 diamet]1 wat]tight except at ! bottom1 :]e x op5s out into an inv]t$ cone1 ! surface ( :i* is pi]c$ ) holes4 ,?is /&s imm]s$ 9 dilute sulphuric acid4 ,a saturat$ solution ( copp] sulphate is next c>efully introduc$1 s z to displace ! acid upw>ds4 ,cry/als ( sulphate ( copp] are introduc$ into ! op5 end at ! top ( cyl9d]1 to fill ! p]=at$ portion at ! bottom4 ,f ! wood5 cov] ( cell a ?ick flat r+ ( amalgamat$ z9c hangs susp5d$ 9 ! dilute acid4 ,c>e %\ld be tak5 n to introduce ! z9c till ! two solutions h become well sep>at$4 ,dur+ action ?is becomes copp]$1 :ile 9 contact ) ! sulphate ( copp]1 b x is n attack$ by ! acid4 ,x is1 h[ev]1 pref]able to pa9t t portion ( ! lead1 :i* is surr\nd$ by ! acid4 ,! height ( ! cell is ab\t #ad4'' ,x w be readily und]/ood t if ?is latt] sy/em be employ$1 special contacts1 :i* break contact :5 ! pressure is remov$1 mu/ be employ$ = ! door or w9d[ contacts4 ,a simple =m is %[n at ,fig4 #eh4 ,illu/ration3 ,fig4 #eh4 ,contacts simil> to ,figs4 #ej1 #ec & #ed1 may be fitt$ on tills or draw]s4 ,s #eh4 ,ano!r useful application ( contact is = ! notification ( any rise or fall ( temp]ature beyond c]ta9 fix$ limits4 ,! devices us$ = ?is purpose are kn[n z fire al>ms1 fro/ al>ms1 & !rmomet] al>ms4 ,! !rmomet] al>m is at once ! mo/ effective & tru/wor?y ( ! =ms kn[n1 z1 besides its delicacy1 x has ! advantage ( be+ able to give notice ( l[1 z well z ( abnormally high temp]ature4 ,! =m usually giv5 to ! electric al>m !rmomet]1 is well %[n at ,fig4 #ei4 ,x consi/s 9 an ord9>y !rmomet] ) a wire project+ into ! tube to a c]ta9 po9t1 say #ajj degrees4 ,! m]cury 9 ! bulb be+ also connect$ ) ano!r wire4 ,:5 ! temp]ature is )9 ! usual climatic range1 ! m]cury does n rea* ! upp] wire4 ,if by reason ( fire or any o!r abnormal heat1 ! temp]ature rises beyond t to :i* ! in/rum5t is set1 ! m]cury rises & t\*es ! upp] wire1 contact is ?us e/abli%$1 & ! bell r+s4 ,illu/ration3 ,fig4 #ei4 ,by giv+ ! !rmomet] ! %ape ( a lett] ,u1 x is possible to notify also a fall bel[ a c]ta9 degree1 z well z a rise beyond a c]ta9 fix$ po9t4 ,^! !rmomet]s are specially us$ by nurs]ym5 & o!rs1 to w>n !m ( ! too great l[]+ ( temp]ature1 or vice v]sa1 9 ! h\ses "u _! *>ge4 ,o!r =ms ( fire al>ms are %[n at ,fig4 #fj & #fa4 ,if a /rip be built up ( two ?9 lay]s ( dissimil> metals rivet$ toge!r1 z ! two metals d n exp& at ! same rate1 ! /rip w b5d to ! "r if heat$1 & to ! left if cool$4 ,9 ! in/rum5t %[n at ,fig4 #fj1 ! application ( heat causes ! flexible /rip c>ry+ ! contact screw1 to b5d ov] till x t\*es ! l[] /op1 :51 ( c\rse1 ! bell r+s4 ,if two /ops are employ$ in/ead ( ! l[] "o only1 ! bell w r+ :5 a l[ temp]ature is rea*$1 :i* causes ! /rip to b5d 9 ! opposite direction4 ,illu/ration3 ,fig4 #fj4 ,illu/ration3 ,fig4 #fa4 ,at ,fig4 #fa is illu/rat$ a novel =m1 9 :i* ! expansion ( air causes contact to be made4 ,x consi/s 9 an air *amb] h]metically clos$ by a corrugat$ metal plate ,i1 simil> to t us$ 9 ! an]oid b>omet]s4 ,:5 ! temp]ature rises to a c]ta9 po9t1 ! expansion ( ! air 9 ! *amb] br+s ! metallic plate into contact ) ! screw1 z %[n bel[4 ,?is closes ! circuit & r+s ! bell 9 ! usual mann]4 ,9 all ^! fire or !rmomet] al>ms1 ! exact degree ( heat at :i* ! bell %all r+1 c be pretty accurately adju/$ by means ( ! contact screws4 ,s #ei4 ,closely alli$ to ^! =ms ( contacts are ! devices :]eby an ord9>y clock or wat* c be made to ar\se ! ov]-dr[sy sleep] by ! r++ ( an electric bell1 :i* 9 ?is case %\ld be ( ! cont9u\s type4 ,all ^! dep5d 9 _! action ^u "s arrangem5t :]eby :5 ! h\r h& ( ! clock or wat* arrives at a c]ta9 giv5 po9t 9 its travel1 x makes contact betwe5 ! batt]y & bell4 ,9 g5]al ! contact piece is atta*$ bodily to ! clock1 b 9 ! v +5i\s arrangem5t illu/rat$ at ,fig4 #fb 7devis$ by ,messrs4 ,b9swang]7 ! contacts are atta*$ to an out] case1 & z ! case ( ! wat* itself =ms "o po9t ( contact1 any wat* t w slip 9 ! case1 may be set to r+ ! bell4 ,illu/ration3 ,fig4 #fb4 ,illu/ration3 ,fig4 #fc4 ,messrs4 ,g5t1 ( ,leice/]1 h also p]fect$ an electric wat*man's clock1 :i* records ! numb] ( places ! wat*man 9 *>ge has visit$ or miss$ on 8 r\nds4 ,?is we illu/rate at ,fig4 #fc4 ,we quote ,messrs4 ,g5t's own words1 9 ! foll[+ description3-- ,x consi/s ( an eight-day clock1 to :i* is atta*$ a disc or table revolv+ ^u a v]tical axis & driv5 by ! me*anism ( ! clock4 ,! disc is cov]$ ) a %eet ( pap]1 atta*$ to x by a b9d+ screw s t x c be remov$ :5 us$ & a clean %eet sub/itut$ = x4 ,ea* %eet ( pap] is divid$ longitud9ally into h\rs &1 if necess>y1 p>ts ( h\rs1 & crosswise into z _m divisions z !re are places to be visit$ by ! wat*man--any numb] f "o to tw5ty4 ,ea* division has a correspond+ m>k]1 :i* indicates1 by ! impression x makes ^u ! pap]1 ! "t ! wat*man visits ! place connect$ ) t m>k]4 ,wires are c>ri$ f ! t]m9als ( ! clock1 "o to ! batt]y1 & "o to ea* press-button fix$ at ! po9ts int5d$ to be visit$ by ! wat*man2 ano!r wire is c>ri$ f ea* press-button to ! o!r end ( ! batt]y4 ,! action is v simple3 :5 ! button is press$ 9 ! curr5t passes ?r\gh a coil c>ry+ an armature & contact break] ) a po9t at ! end ( a long arm2 a hamm]-l motion is giv5 to ! po9t]1 & a di/9ct p]=ation made 9 ! c>d4 ,x is usual to h ! press-button 9 a box lock$ up1 ( :i* ! wat*man only has ! key4 ,! clock may be 9 ! (fice or b$room ( ! manag] or head ( ! e/abli%m5t1 :o c ?us1 f "t to "t1 satisfy himself ( ! wat*man's vigilance4 ,! record %\ld be exam9$ 9 ! morn+1 & replac$ by a clean %eet ( c>d4 ,?is clock receiv$ ! special m5tion ( ,h] ,maje/y's ,commission]s 9 ,lunacy1 & has be5 adopt$ by "s ( ! l>ge/ asylums 9 ! c\ntry4 ,we h rec5tly made an important improvem5t by add+ a relay = e m>k]1 ?us enabl+ a local batt]y ( great] p[] to be us$ = actuat+ ! m>k]s4 ,?is has made no alt]ation 9 ! appe>ance ( ! clock1 z ! relays are conta9$ )9 ! cornice at ! top ( ! clock case4 ,s #fj4 ,by means ( a float1 x is possible to give notice ( ! height ( wat] 9 a tank1 a res]voir1 or ev5 ( ! /ate ( ! tide4 ,9 ^! cases all t is ne$$ is a float ) an arm1 hav+ a suitable contact atta*$1 s t :5 ! wat] rises to ! level ( ! float & lifts x1 x causes ! contact piece to complete ! circuit ?r\gh a set screw4 ,or ! float may be atta*$ to an arm hav+ a c]ta9 play 9 bo? directions1 i4e41 up & d[n1 )9 :i* no contact is made1 z ! arm has a contact piece on ei!r side1 :i* c t\* ei!r an upp] or a l[] contact screw1 accord+ to :e!r ! tide is l[ or high1 or :e!r ! lock or tank is ne>ly empty or too full4 ,illu/ration3 ,fig4 #fd4 ,s #fa4 ,sometimes x is conv5i5t to be able to r+ an ord9>y trembl+ bell cont9u\sly1 z :5 a ma/] wi%es to wake a memb] ( 8 family or a s]vant2 or aga91 to cut a giv5 bell or bells out ( circuit altoge!r4 ,! arrangem5ts by :i* ?is c be effect$1 are kn[n z swit*es4 ,( swit*es !re are two k9ds1 namely1 plugswit*es or int]ruptors1 & lev] swit*es4 ,! =m] consi/s ess5tially 9 two /\t plates ( brass affix$ to a base bo>d ( any insulat+ mat]ial4 ,^! brass plates are set p>allel to ea* o!r1 a %ort di/ance ap>t1 & ! c5tre ( ! fac+ edge is holl[$ out to take a brass tap] plug4 ,a b9d+ or o!r screw is fix$ to ea* brass plate1 to connect up to ! lead+ wires4 ,:5 ! plug is 9 its socket1 ! circuit betwe5 ! two plates 7& consequ5tly betwe5 ! batt]y & bell1 etc47 is complete2 :5 ! plug is out1 ! contact is brok54 ,?is =m ( swit* is subject to "w out ( ord]1 ow+ to ! fact t ! tap] plug gradually wid5s ! hole1 s t ! contact becomes unc]ta9 or defective altoge!r4 ,by f> ! bett] =m ( swit* is ! lev] swit*1 z %[n at ,fig4 #fd4 ,?is consi/s 9 a movable metal lev] or arm1 :i* is held by a /rong spr+ 9 contact ) ! upp] b9d+ screw4 ,x c be made to slide ov] to ! "r or left ( ! c5tre1 at its l[] or free end1 z f> z ! b9d+ screws or /uds %[n1 :i* act at once z /ops & po9t ( connection to wires4 ,:5 ! arm or lev] is 9 ! c5tre no contact is made b if x be pu%$ ov] to ! "r1 x slides on a brass /rip let into & ly+ flu% ) ! base4 ,contact is ?us made betwe5 ! upp] b9d+ screw & ! left-h& screw4 ,if !re is ano!r brass /rip on ! left-h& side 7z %[n 9 ! figure71 contact may be made ) ano!r bell1 etc41 by slid+ ! arm to ! left2 or aga91 if no metal /rip be plac$ on ! left side ! contact may be brok5 by pu%+ ! arm t[>ds ! left-h& /ud4 ,s #fb4 ,a key is ano!r =m ( contact1 by means ( :i* a long or %ort completion ( circuit c be made by simply tapp+ on ! knob4 ,x is p>ticul>ly useful :5 x is desir$ to transmit signals1 ei!r by r++ or o!rwise4 ,x consi/s1 z may be se5 at ,fig4 #fe1 ( a lev] or arm ( brass1 pivot$ at its c5tre1 furni%$ ) a spr+ :i* keeps ! portion "u ! knob out ( contact ) ! /ud 9 ! front ( ! base-bo>d4 ,z bo? ! /ud & ! lev] are connect$ to b9d+ screws communicat+ ) ! batt]y & bell1 etc41 x is evid5t t on depress+ ! key ! circuit ) ! bell w be complet$ = a long] or %ort] p]iod1 v>y+ ) ! duration ( ! depression4 ,h5ce1 ei!r by us+ preconc]t$ signals ( %ort & long r+s to signify c]ta9 common words1 su* z a long r+ = ,no1 & a %ort "o = ,yes1 or by an adaptation ( ! ord9>y ,morse code1 intelligible conv]sation c be kept up betwe5 h\se & /able1 etc41 etc41 by means ( a key & a bell4 ,z ,mr4 ,edw9son has giv5 mu* "t to ! elucidation ( ?is sy/em ( bell signall+1 ,i _c d bett] ?an quote 8 in/ructions1 z giv5 9 ,amateur ,"w3-- ,= ?is purpose preconc]t$ signals h be5 agre$ ^u or inv5t$ z requir$1 & ^! h be5 f\nd to be irksome & difficult to rememb]1 because con/ruct$ )\t any ref]5ce to a def9ite plan4 ,we may1 h[ev]1 r$uce bell signals to a def9ite sy/em1 & use ?is sy/em or code z a means to c>ry on conv]sation at a di/ance z intellig5tly z x c be done by a pair ( telegraph in/rum5ts4 ,9 fact1 ! ,morse telegraph code c be easily adopt$ = use ) electric bells ( ! vibrat+ or trembl+ type1 & its alphabet1 z app5d$ bel[1 easily le>nt4 ,! lett]s ( ! alphabet are repres5t$ by long /rokes & %ort /rokes on ! bell1 z "h %[n4-- ,a 4- ,b -444 ,c -4-4 ,d -44 ,e 4 ,f 44-4 ,g --4 ,h 4444 ,i 44 ,j 4--- ,k -4- ,l 4-44 ,m -- ,n -4 ,o --- ,p 4--4 ,q --444 ,r 4-4 ,s 444 ,t - ,u 44- ,v 444- ,w 4-- ,x -44- ,y -4-- ,z --44 ,* ---- 3,a 7ae7 4-4- 3,o 7oe7 ---4 3,u 7ue7 44-- #a 4---- #b 44--- #c 444-- #d 4444- #e 44444 #f -4444 #g --444 #h ---44 #i ----4 #j ----- ,x w be notic$ t ! /rokes to repres5t a lett] d n 9 any case exce$ f\r1 & t all ! figures are repres5t$ by five /rokes ( v>y+ l5g? to ea* figure4 ,/ops1 & o!r m>ks ( punctuation1 are repres5t$ by six /rokes1 :i* are 9 _! comb9ation repres5tations ( two or ?ree lett]s respectively1 z %[n bel[3-- ,comma 717 by ,a ,a ,a or 4-4-4- ,full /op 747 ,i ,i ,i 444444 ,int]rogation 787 ,u ,d 44--44 ,hyph5 7-7 ,b ,a -4444- ,apo/rophe 7'7 ,w ,g 4----4 ,inv]t$ commas 77 ,a ,f 4-44-4 ,p>5!sis 77 ,k ,k -4--4- ,semi-colon 727 ,k ,* 4----- ,surprise 767 ,n ,* -4---- ,colon 737 ,i ,* 44---- ,9 s5d+ signals to indicate /ops1 no reg>d mu/ be _h to ! lett]s :i* !y repres5t2 ^! are only giv5 z aids to memory1 & are n to be repres5t$ sep>ately on ! bell4 ,bell signals mu/ be giv5 ) a c]ta9 am\nt ( regul>ity z to "t2 inde$1 to c>ry on a conv]sation 9 ?is way x is necess>y to be z punctili\s 9 "t z :5 play+ a piece ( music on a piano1 if ! signals are to be und]/ood4 ,! dots ( ! signal %\ld !re=e be repres5t$ 9 "t by "o1 & ! da%es by two1 :il/ ! spaces betwe5 words & figures :]e a /op does n int]v5e %\ld be repres5t$ by a pause equal to t tak5 by a p]son c\nt+ ?ree1 ! space betwe5 a ^w & a /op be+ ( ! same duration4 ,to make ?is m cle> ,i give an example4 ,! mi/ress signals to h] coa*man3-- ,g ,e ,t ,t ,h ,e --4 4 - - 4444 4 #bba #a #b #c #b #aaaa #a #c ,c ,a ,r ,r ,i ,a ,g ,e -4-4 4- 4-4 4-4 44 4- --4 4 #baba #ab #aba #aba #aa #ab #bba #a #c ,r ,e ,a ,d ,y 4-4 4 4- -44 -4-- #aba #a #ab #baa #babb ,! coa*man replies3-- ,r ,e ,a ,d ,y 4-4 4 4- -44 -4-- #aba #a #ab #baa #babb ,:5 ! mi/ress is ready %e signals3-- ,b ,r ,i ,n ,g ,t ,h ,e -444 4-4 44 -4 --4 - 4444 4 #baaa #aba #aa #ba #bba #c #b #aaaa #a #c ,c ,a ,r ,r ,i ,a ,g ,e -4-4 4- 4-4 4-4 44 4- --4 4 #baba #ab #aba #aba #aa #ab #bba #a ,& ! coa*man replies ) a s+le long r+ to signify t he und]/&s4 ,x w be f\nd conv5i5t to h an answ]+ signal f ! receiv+ end ( ! l9e to ea* ^w sep>ately4 ,?is mu/ be s5t 9 ! pause aft] ea* ^w1 & consi/s ( ! %ort signal ,e 4 :5 ! ^w is und]/ood1 or ! d\ble %ort signal ,i 44 :5 ! ^w is n und]/ood4 ,a negative reply to a "q may be giv5 by ! signal = ,n -41 & an affirmative by ! signal = ,,ae 4-4-2 o!r abbreviations may be devis$ & us$ :]e desir$4 ,! code hav+ be5 committ$ to memory1 x w be q easy to transpose ! words & s5d messages 9 cyph] :5 we wi% to make a confid5tial communication2 or ! bells may be muffl$ "u a ?ick cloak1 & ?us1 :il/ ! measur$ beats are he>d by ! p]son = :om ! signal is int5d$1 o!rs outside ! room w n be annoy$ by !m4 ,illu/ration3 ,fig4 #fe4 ,s #fc4 ,at ,s #dh1 we notic$ t a device kn[n z a ,relay is a conv5i5t1 if n an ess5tial mode ( work+ cont9u\s r++ bells4 ,"h we w direct our att5tion to its /ructural arrangem5t1 & to its adaptations4 ,let u suppose t we _h to r+ a bell at a consid]able di/ance1 s f> inde$ t a s+le batt]y w\ld n en]gise ! electro-magnets ( an ord9>y bell1 suffici5tly to produce a di/9ct r+4 ,x is evid5t t if we c\ld signal1 ev] s feebly1 to an att5dant at ! o!r end ( ! l9e to make contact ) ano!r batt]y at ! di/ant end ( ! l9e to 8 bell1 by means1 say1 ( a key simil> to t %[n at ,fig4 #fe1 we %\ld get a cle> r+1 s9ce ?is second batt]y1 be+ close to ! bell1 w\ld s5d pl5ty ( curr5t to en]gise ! bell's magnets4 ,b ?is w\ld require a p]son con/antly 9 att5dance4 ,n[ ! relay does ?is automatically2 x relays ano!r batt]y 9 ! circuit4 ,! mann] 9 :i* x effects ?is w be r5d]$ cle>1 on exam9ation ( ,fig4 #ff4 ,"h we h an armature ,a atta*$ to a light spr+1 :i* c play betwe5 an insulat$ /op ,c1 & a contact screw ,b4 ,! play ( ?is armature c be regulat$ to a nicety by turn+ ! screws ,b or ,c4 ,^! two screws are bo? borne by a d\ble b5t arm 7( metal7 affix$ to ! pill> ,d4 ,?is pill> is sep>at$ f ! re/ ( ! frame by an insulat+ coll> or wa%] ( ebonite1 s t no curr5t c pass f ,e to ,d1 unless ! armature be pull$ d[n s z to make contact ) ! contact screw ,b4 ,j "u ! armature1 /&s ! electro-magnet ,g1 :i* :5 en]gis$ c & does pull d[n ! armature ,a4 ,x w be readily und]/ood t if we connect ! wires f ! electro-magnet ,g1 to ! wires proce$+ f ! batt]y & pu% 7or o!r =m ( contact7 at ! di/ant /ation1 ! electro-magnet1 be+ w\nd ) a l>ge quantity ( f9e wire1 w become suffici5tly magnetiz$ to pull ! armature d[n ?r\gh ! small space int]v5+ betwe5 ,c & ,b2 s t if ! screws ,d & ,e are connect$ respectively to ! free t]m9als ( a batt]y & bell c\pl$ toge!r at ! ne>] /ation1 ?is second batt]y w be ?r[n into circuit ) ! bell1 & cause x to r+ z well & z exactly z if ! mo/ skilful & mo/ tru/wor?y assi/ant 7 9 communication ) ! di/ant signall]4 ,e tap1 e release ( ! contact1 7be x pu%1 key1 or swit*7 made at ! di/ant end1 w be fai?fully reproduc$ at ! ne>] end1 by ! motion ( ! armature ,a4 ,= ?is reason we may use a comp>atively weak batt]y to "w ! relay1 :i* 9 its turn br+s a m p[]ful & local batt]y into play1 = do+ :atev] "w is requir$4 ,9 cases :]e a numb] ( calls are requir$ to be made simultane\sly f "o c5tre1 z 9 ! case ( call+ assi/ance f sev]al fire eng9e /ations at once1 a relay is fix$ at ea* /ation1 ea* connect$ ) its own local batt]y & bell4 ,! curr5t f ! s5d+ /ation passes direct ?r\gh all ! relays1 connect+ all ! local batt]ies & bells at ! same "t4 ,?is is p]haps ! be/ way ( r++ any numb] ( bells f "o pu% or contact1 at a di/ant po9t4 ,ord9>y trembl+ bells1 unless fitt$ ) an appropriate contrivance1 _c well be rung if connect$ up 9 s]ies4 ,?is is ow+ to ! fact t ! clapp]s ( ! bells d n all break or make contact at ! same "t1 s t int]mitt5t r++ & int]ruptions take place4 ,) s+le /roke bells1 ?is is n ! case1 z ! pull+ d[n ( ! armature does n break ! contact4 ,illu/ration3 ,fig4 #ff4 ,illu/ration3 ,fig4 #fg4 ,illu/ration3 ,fig4 #fh4 ,s #fd4 ,we n[ h to consid] ^? contrivances by means ( :i* x is possible = an att5dant to "k :5 a s+le bell is actuat$ by a numb] ( pu%es 9 diff]5t rooms1 etc41 f :5ce ! signal emanates4 ,^! contrivances are kn[n z indicators4 ,indicators may be conv5i5tly divid$ into #c classes1 viz43--#a/1 indicators ) me*anical replacem5ts2 #bnd1 ^? ) electrical replacem5ts2 & #crdly1 ^? :i* are self replac+4 ,( ! =m] class we may m5tion two typical =ms1 namely1 ! ord9>y fall back indicator1 & ! drop indicator4 ,all indicators dep5d 9 _! action on ! sudd5 magnetisation ( an electro-magnet by ! same curr5t t works ! electric bell at ! "t ! call is s5t4 ,to und]/& ! way 9 :i* ?is may be effect$1 let ! read] turn to ! illu/ration ( ! ,relay 7,fig4 #ff71 & let him suppose t ! pill> ,d1 ) its accompany+ rectangle ,b ,c1 7 remov$1 leav+ only ! electro-magnet ,g1 ) its frame & armature ,a4 ,if ?is armature holds up a light tablet or c>d1 on :i* is m>k$ ! numb] ( ! room1 x is evid5t t any d[nw>d motion ( ! armature1 su* z w\ld occur if ! electro-magnet 7 en]gis$ by a curr5t pass+ ar\nd x1 w\ld let ! tablet fall1 s z to become visible ?r\gh a hole cut 9 ! frame conta9+ ?is contrivance4 ,x is also equally evid5t t ! c>d or tablet w\ld require replac+ by h&1 aft] hav+ once fall51 to r5d] x capable ( aga9 notify+ a call4 ,fig4 #fg %[s ! work+ p>ts ( "o ( ^! drop indicators1 z s5t out by ,messrs4 ,b9swang]4 ,9 ano!r modification1 kn[n z ,?orpe's ,semaphore ,indicator1 we h a mo/ +5i\s application ( ! same pr9ciple 9 a v compact =m4 ,9 ?is 7,fig4 #fh71 ! electro-magnet is plac$ directly beh9d a disc-%ap$ iron armature1 on :i* is pa9t$ or m>k$ ! numb] ( ! room etc4 79 ?is case #d72 ?is armature is atta*$ by a spr+y %ank to ! drop b>1 %[n to ! left ( ! electro-magnet4 ,9 front ( ! armature is a light metal disc1 also pivot$ on ! drop b>4 ,?is engages 9 a cat* above1 :5 pu%$ up s z to cov] ! numb]4 ,:5 pu%$ up1 ! spr+ ( ! armature reta9s x 9 its place s t ! numb] is hidd54 ,:5 ! curr5t passes ar\nd ! electro-magnet1 ! armature is pull$ t[>d x1 & ?us frees ! cov]+ disc1 :i* !re=e falls1 & displays ! numb]4 ,! ord9>y =m ( fall back indicator 7a misnom]1 by ! way1 s9ce ! indicator falls =w>ds7 is well illu/rat$ at ,fig #fi4 ,"h we h an ord9>y electro-magnet ,a1 ) its wires w w' /&+ ov] an armature ,b atta*$ to a spr+ ,c1 :i* be>s on its l[] extremity1 a too!d projection :i* s]ves to hold up ! %ort arm ( ! b5t lev] ,d1 :i* supports ! numb] plate ,e4 ,:5 ! electro-magnet ,a is en]gis$ by ! curr5t1 x pulls up ! armature ,b1 :i* releases ! det5t ,d f ! too? ,c2 ! numb] plate !re=e falls =w>ds1 z %[n by ! dott$ l9es1 & %[s itself at ! ap]ture ,e'1 :i* is 9 front ( ! indicator frame4 ,to replace ! numb] out ( sight1 ! att5dant pu%es back ! plate ,e1 till x aga9 engages ! b5t lev] ,d 9 ! too? ,c4 ,?is replacem5t ( ! numb] plate1 :i* ! att5dant 9 *>ge is oblig$ to p]=m1 gives rise to confusion1 if ?r\gh c>elessness x is n effect$ at once1 z two or m numb]s may be left %[+ at "o "t4 ,= ?is reason1 indicators :i* require no extrane\s assi/ance to replace !m1 are pref]r$ by _m4 ,indicators ) electrical replacem5ts meet 9 "p ! necessities ( ! case4 ,?is =m ( indicator consi/s usually ( a p]man5t b> magnet pivot$ ne> its c5tre1 s t x c hang v]tically betwe5 ! two poles ( an electro-magnet plac$ at its l[] extremity4 ,! upp] extremity c>ries ! numb] plate1 :i* %[s ?r\gh ! ap]ture 9 ! frame4 ,?is b> magnet is made a trifle heavi] at ! upp] end1 s t x mu/ re/ aga9/ ei!r ! "o or o!r pole ( ! electro-magnet bel[4 ,if ! nor? pole ( ! b> magnet re/s aga9/ ! "r h& pole ( ! electro-magnet :5 ! numb] does n %[1 we c cause ! b> magnet to cross ov] to ! o!r pole1 & display ! numb] by s5d+ a curr5t ?r\gh ! electro-magnet 9 su* a direction z to make its "r h& pole a nor? pole1 & its left h& a s\? pole4 ,?is is because ! two nor? poles w repel ea* o!r1 :ile ! s\? w attract ! nor?4 ,on be+ once tilt$ ov]1 ! b> magnet _c return to its =m] position1 until ! p]son :o us$ ! bell s5ds a curr5t 9 ! opposite direction 7:i* he c d by means ( a rev]s+ swit*71 :5 ! poles ( ! electro-magnet be+ rev]s$1 ! b> magnet w be pull$ back into its orig9al position4 ,indicators ( ?is class1 ow+ to ! fact t _! replacem5t dep5ds on ! pol>ity ( ! b> magnet1 are also kn[n z pol>is$ indicators4 ,illu/ration3 ,fig4 #fi4 ,s #fe4 ,= g5]al effici5cy & tru/wor?9ess1 ! p5dulum indicator2 z %[n at ,fig4 #gj1 is unsurpass$4 ,x consi/s ( an electro-magnet ) prolongation at ! free end on :i* is delicately pivot$ a s(t iron armature4 ,f ! c5tre ( ?is armature hangs1 p5dulum fa%ion1 a light brass rod c>ry+ a vane ( flut$ silv] glass1 or a c>d ) a numb] on x1 z may be f\nd mo/ conv5i5t4 ,?is vane or c>d hangs j be=e ! ap]ture 9 ! indicator frame4 ,/ops are usually plac$ on ea* side ( ! p5dulum rod to limit ! sw+4 ,:5 ! electro-magnet is magnetis$ by ! passage ( ! curr5t1 ! armature is pull$ sudd5ly on "o side1 & !n ! p5dulum sw+s backw>ds & =w>ds 9 front ( ! ap]ture = "s m9utes be=e x comes to re/4 ,:5 fitt$ ) silv] flut$ glass1 ! motion ( ! vane is cle>ly visible ev5 9 badly light$ places4 ,z ! p5dulum1 aft] p]=m+ sev]al oscillations1 comes to re/ by itself 9 front ( ! ap]ture1 ?is indicator requires no sett+4 ,messrs4 ,b9swang] fit ^! indicators ) d\ble core magnets1 & h a pat5t$ adju/m5t = regulat+ ! duration ( ! sw+s ( ! p5dulum1 :i* may be made to sw+ = two or ?ree m9utes :5 ! circuit is complet$ by press+ ! pu%2 x !n returns to its normal position1 ?us sav+ ! s]vant ! tr\ble ( replac+ ! drop4 ,illu/ration3 ,fig4 #gj4 ,messrs4 ,g5t1 ( ,leice/]1 h also pat5t$ a device 9 connection ) ?is =m ( indicator1 :i* we give 9 ! pat5tee's own words3--,! objection s frequ5tly urg$ aga9/ ! use ( ,electric ,bells1 t ! s]vants _c be dep5d$ ^u to p]=m ! op]ation ( replac+ ! signals1 _c any long] apply1 = ! p5dulum signals require no att5tion :atev]4 ,x consi/s ( an electro-magnet hav+ =ks /&+ up 9 :i* ,v op5+s are made4 ,an armature ( s(t iron1 ) a piece ( ?9 /eel project+ at ea* end lies susp5d$ at ! bottom ( ! ,v op5+1 a brass /em c>ry+ ! signal c>d is screw$ into ! armature1 ! action be+1 t :5 a curr5t is all[$ to pass ?r\gh ! electro-magnet ! armature ) ! p5dulum is drawn t[>ds x & held !re until ! curr5t ceases to pass1 :5 x in/antly looses its hold ( ! armature1 :i* sw+s away & cont9ues to oscillate = two or ?ree m9utes1 s t if ! s]vant happ5s to be out ( ! way1 x may be se5 on h] return :i* p5dulum has be5 set 9 motion4 ,! ,p5dulum ,indicator we h rec5tly pat5t$ is entirely self-conta9$4 ,! magnet has its project+ poles rivet$ into ! brass base :i* c>ries ! flag4 ,! flag is con/ruct$ z ,fig4 #gj1 b sw+s 9 clos$ be>+s1 :i* prev5ts its j]k+ out ( its place1 & enables u to s5d x out 9 position ready = use4 ,x w be se5 ?is pat5t$ improvem5t makes all screws & plates z =m]ly us$ = secur+ ! p>ts unnecess>y4 ,x w be se5 at once t ?is is simplicity itself1 & has no?+ ab\t x :i* may by any possibility be put out ( ord]1 ei!r by w>p+ or %r9k+ ( ! case or c>elessness ( att5dants4 ,illu/ration3 ,fig4 #ga4 ,!re is only "o po9t t ne$s fur!r notice ) reg>d to ^! p5dulum indicators1 & t is1 t s9ce ! rapid break & make contact ( ! r++ bell int]f]es some:at ) ! prop] action ( ! indicator magnet1 x is always advisable to "w ! indicator by means ( a relay 7fix$ 9 ! same frame7 & a local batt]y4 ,?is is %[n 9 ,fig4 #ga1 :]e a second pair ( wires atta*$ to ,c & ,c1 to ! extreme "r ( ! indicator frame1 are br\ght f ! same batt]y to "w ! indicator & conta9$ relay4 ,x is n advisable1 h[ev]1 ) ! p5dulum indicator1 to use ! same batt]y = ! indicator2 ! relay %\ld ?r[ a local batt]y into ! indicator circuit4 ,9 ,fig4 #ga six pu%es are %[n to ! left ( ! indicator frame4 ,^!1 ( c\rse1 are suppos$ to be 9 z _m diff]5t rooms4 ,illu/ration3 ,fig4 #gb4 ,we close ?is *apt] ) an engrav+ ( a v compact & neat =m ( drop indicator devis$ by ,messrs4 ,g5t1 & call$ by !m a ,tripol> ,indicator4 ,x consi/s1 z ! "n implies1 ( a s+le magnet1 hav+ "o end ( ! iron core z "o pole1 ! o!r end ext5d+ on ea* side l a ,v1 =m+1 z x 71 ?ree poles4 ,?\gh b "o bobb9 is us$1 ! effect is v p[]ful4 ,!re are no spr+s or o!r complications1 s t ! arrangem5t is adapt$ = %ip use1 z are also ^? repres5t$ at ,figs4 #fg & #fh4 ,p5dulum & fall-back indicators1 z well z pol>is$ indicators1 ow+ to ! delicacy ( ! adju/m5ts1 are unfitt$ = use on bo>d %ip1 or 9 ! cabs ( lifts1 :]e ! sudd5 jolts & j]ks are sure to move ! indicators1 & falsify ! indications4 ,! tripol> indicator is illu/rat$ at ,fig4 #gb4 ,,*apt] ,v4 ,,on ,,wir+1 ,,connect+ ,,up1 ,,& ,,localis+ ,,faults4 ,s #ff4 ,h[ev] good may be ! bells1 indicators1 batt]ies1 etc41 us$ 9 an electric bell in/allation1 if ! wir+ be 9 any wise faulty1 ! sy/em w surely be cont9ually break+ d[n1 & giv+ rise to dissatisfaction4 ,x is !re=e ( ! highe/ importance t ! workman1 if he value 8 good "n1 %\ld pay ! greate/ att5tion to ensure t ?is "p ( 8 "w be well & ?or\ghly done4 ,?is is all ! m necess>y1 s9ce :ile ! bells1 batt]ies1 relays1 pu%es1 etc41 are easily got at = exam9ation & repair1 ! wires1 :5 once laid1 are n s easily exam9$1 & x entails a great deal ( tr\ble to pull up floor bo>ds1 to remove skirt+s etc41 9 ord] to be able to ov]haul & replace defective wires or jo9ts4 ,! fir/ consid]ation ( c\rse1 is ! k9d & size ( wire fitt$ to c>ry ! curr5t = indoor & outdoor "w4 ,n[ ?is mu/ evid5tly dep5d on ?ree po9ts4 #a/1 ,! am\nt ( curr5t 79 ampe'res7 requir$ to r+ ! bell4 #bnd1 ,! batt]y p[] x is int5d$ to employ4 #crd1 ,! di/ance to :i* ! l9es are to be c>ri$4 ,f practical exp]i5ce ,i h f\nd t x is j possible to r+ a #b-a_/b bell ) #a_/b an ampe're ( curr5t4 ,let u consid] :at ?is w\ld all[ u to use1 9 ! way ( batt]ies & wire1 to r+ su* a bell4 ,! electro-motive =ce ( a s+le ,leclan*e' cell is1 z we h se5 at ,s #ch1 ab\t #a4f volt1 & ! int]nal resi/ance ( ! qu>t size1 ab\t #a4a ohm4 ,no4 #bj gauge copp] wire has a resi/ance ( ab\t #a4b ohm to ! p\nd1 & 9 a p\nd 7( ! cotton cov]$ wire7 !re are ab\t #fj y>ds4 ,suppos+ we 7 to use #fj y>ds ( ?is wire1 we %\ld h a wire resi/ance ( #a4b ohm1 an int]nal resi/ance ( #a4a ohm1 & a bell resi/ance ( ab\t #j4a ( an ohm1 altoge!r ab\t #b4d ohms4 ,s9ce ! ,e4,m4,f4 ( ! cell is #a4f volt1 we mu/ divide ?is by ! total resi/ance to get ! am\nt ( curr5t pass+4 ,t is to say3-- ,ohms4 ,volts4 ,ampe'res4 #b4d7 #a4fj 7#j4ff1 or ab\t #b_/c ( an ampe're2 j a little ov] :at is absolutely necess>y to r+ ! bell4 ,n[ ?is w\ld all[ no?+ = ! det]ioration 9 ! batt]y1 & ! increas$ resi/ance 9 ! pu%es1 jo9ts1 etc4 ,we may safely say1 !re=e1 t no copp] wire1 ( less diamet] ?an ,no4 #ah gauge 7#dh_/ajjj ( an in* diamet]7 %\ld be us$ 9 wir+ up h\se bells1 except only 9 v %ort circuits ( two or ?ree y>ds1 ) "o s+le bell 9 circuit2 & z ! diff]5ce 9 price betwe5 ,no4 #ah & ,no4 #bj is v trifl+1 ,i %\ld /rongly recomm5d ! bell-fitt] to adh]e to ,no4 #ah1 z 8 smalle/ /&>d size4 ,x w\ld also be well to s proportion ! size & arrangem5t ( ! batt]ies & wires1 t1 at ! "t ( sett+ up1 a curr5t ( at lea/ "o ampe're %\ld fl[ ?r\gh ! entire circuit4 ,?is w all[ m>g9 = ! weak5+ ( ! batt]y1 :i* takes place aft] x has be5 = "s mon?s 9 use4 ,z a guide z to :at resi/ance a giv5 l5g? ( copp] wire introduces into any circuit 9 :i* x may be employ$1 ,i subjo9 ! foll[+ table ( ! ,birm+ham wire gauge1 diamet] 9 #a1jjj?s ( an in*1 y>ds p] lb41 & resi/ance 9 ohms p] lb4 or #ajj y>ds1 ( ! wires :i* ! fitt] is likely to be call$ ^u to employ3-- ---------------------------------------- -------------------- ,table ( ,resi/ance & l5g?s p] lbs4 #ajj y>ds ( cotton cov]$ copp] wires4 ---------------------------------------- -------------------- ,birm+ham ,diamet] 9 ,y>ds ,ohms4 ,ohms4 p] ,wire ,gauge4 #ajjj? ( p] lb4 p] lb4 #ajj y>ds4 an in*4 ---------------------------------------- ---------------- ,no4 #ab #ajj #i #j4jcdb #j4jjch #ad #hj #ae #j4jhej #j4jjid #af #fb #bd #j4bbci #j4jbdi #ah #dh #da #j4fijj #j4jgff #bj #da #ei #a4bajj #j4accc #bb #cb #aji #c4ajjj #j4cddd ---------------------------------------- -------------------- ,s #fg4 ,:atev] gauge wire be select$1 x mu/ be c>efully insulat$1 to avoid all *ance contact ) nails1 /aples1 metal pipes or o!r wires4 ,! be/ insulation = wires employ$ indoors is gutta-p]*a1 surr\nd$ ) a coat+ ( cotton w\nd ov] x1 except only 9 cases :5 ! atmosph]e is excessively dry4 ,9 ^!1 z ! gutta-p]*a is apt to crack1 india-rubb] z ! inn] coat+ is pref]able4 ,if ,no4 #ah wire be us$1 ! ?ickness ( ! entire insulat+ coat+ %\ld be ?ick en\gh to br+ x up to ,no4 #aj gauge1 say a little ov] #a_/aj? in* 9 diamet]4 ,!re is "o po9t t w be f\nd v important 9 practice1 & t is to h ! cotton cov]+ on ! wires lead+ to ! bells ( a diff]5t col\r f t on ! return wires2 9 o!r words1 ! wires />t+ f ! z9c poles ( ! batt]y to ! bells1 indicators1 relays1 etc41 %\ld be ( a diff]5t col\r f t lead+ f ! c>bon poles to ! bells1 etc4 ,att5tion to ?is app>5tly trifl+ matt]1 w save an inf9ite am\nt ( tr\ble 9 connect+ up1 repair+1 or add+ on fre% bran* circuits4 ,= outdoor "w1 wire ( ! same gauge 7,no4 #ah7 may g5]ally be us$1 b x mu/ be cov]$ to ! ?ickness ( #a_/aj ) pure gutta-p]*a1 & ov] ?is mu/ be w\nd tape s]v$ ) ,/ockholm t>4 ,wires ( ?is description1 ei!r ) or )\t ! t>r$ tape cov]+1 may be obta9$ f all ! lead+ electricians' sundriesm54 ,_m firms use copp] wire t9n$ previ\s to be+ insulat$4 ,?is t9n+ s]ves two good purposes1 #a/1 ! copp] wire does n v]digris s easily2 #bndly1 x is m easily sold]$4 ,on ! o!r h&1 a t9n$ wire is always a little h>d]1 & pres5ts a little high] resi/ance4 ,:5ev] wires are to be jo9$ toge!r1 ! ends to be jo9$ mu/ be c>efully dive/$ ( _! cov]+ = a l5g? ( ab\t ?ree in*es1 ! copp] c>efully clean$ by scrap+ & s&-pap]+1 twi/$ tightly & ev5ly toge!r1 z %[n 9 ,fig4 #gc ,a1 & sold]$ ) ord9>y s(t sold] 7)\t spirits71 & a little res9 or composite c&le z a flux4 ,a heavy plumb]'s sold]+ iron1 or ev5 a t9man's bit1 is n well adapt$ = ?is purpose1 & ! bl[pipe is ev5 worse1 z ! great heat melts & spoils ! gutta-p]*a cov]+4 ,! be/ =m ( bit1 is "o made out ( a /\t piece ( r\nd copp] wire #a_/d ?ick ) a nick fil$ 9 its upp] surface = ! wire to lie 9 7see ,fig4 #gc ,b74 ,?is may be fa/5$ into a wood5 h&le1 & :5 requir$ heat$ ov] ! flame ( a _s lamp4 ,:5 ! sold]+ has be5 neatly effect$1 ! wa/e ends a & b ( ! wire %\ld be cut (f flu%4 ,! wire mu/ !n be c>efully cov]$ ) w>m ,pr\t's ela/ic or s(t5$ gutta-p]*a1 heat$ & knead$ r\nd ! wire ) ! f+]s 7moi/5$ s z n to /ick7 until ! jo9t is ( ! same size z ! re/ ( ! cov]$ wire4 ,z a fur!r precaution1 ! jo9ts %\ld be wrapp$ ) a lay] ( t>r$ tape4 ,let me /rongly dissuade ! fitt] f ev] be+ cont5t$ ) a simply twi/$ jo9t4 ,al?\gh ?is may & does act :ile ! surfaces are /ill clean1 yet ! copp] soon oxidises1 & a poor non-conduct+ jo9t is ! f9al result4 ,t'll d w n d = electric bell-fitt+4 ,illu/ration3 ,fig4 #gc4 ,s #fh4 ,:5ev] possible1 ! wir+ ( a h\se1 etc41 = bell "w1 %\ld be done z soon z ! walls are up & ! ro( is on4 ,! %orte/ & /raighte/ conv5i5t r\te f bell to batt]y1 etc41 %\ld always be *os5 :]e practicable to facilitate draw+ ! wire ?r\gh & to avoid ! loss ( curr5t :i* ! resi/ance ( long l5g?s ( wire inevitably entails4 ,! wires %\ld be run 9 light z9c tubes nail$ to ! wall4 ,9 jo9+ up sev]al l5g?s ( tub+1 ! end ( "o piece ( tube %\ld be op5$ out consid]ably ( a trumpet %ape = ! o!r piece to slip 92 & ! end ( ?is latt] %\ld also be slightly op5$ out1 s z n to cat* 9 ! cov]+ ( any wire drawn ?r\gh x4 ,! greate/ c>e mu/ be ex]cis$ 9 draw+ ! wires ?r\gh ! tubes or o!rwise1 t ! cov]+ be n abrad$1 or else leakage at ?is po9t may take place4 ,9 cases :]e tubes already exi/1 z 9 replac+ old crank bells by ! electric bells1 ! new wires c be drawn ?r\gh ! tubes1 by ty+ ! ends ( ! new wire to ! old wire1 & c>efully pull+ ?is out1 :5 x br+s ! new wire ) x4 ,or if ! tubes are already empty1 "s /raight /\t wire may be run ?r\gh ! tubes1 to :i* ! new wires may be atta*$1 & !n drawn ?r\gh1 us+1 ( c\rse1 e possible precaution to avoid ! abrasion ( ! insulat+ cov]+ ( ! wire1 :i* w\ld surely entail leakage & loss ( curr5t4 ,all ! old fitt+s1 cranks1 lev]s1 etc41 mu/ be remov$1 & ! holes left1 c>efully fill$ ) d[els or pla/]4 ,9 ^? cases :]e x is q impossible to lay ! wires 9 z9c or wood5 tubes 7z 9 putt+ up wires 9 furni%$ rooms already pap]$1 etc471 ! wires may be run along ! walls1 & susp5d$ by /aples driv5 9 ! lea/ noticeable places2 b 9 no case %\ld ! two wires 7g & return7 lie "u ! same /aple1 = fe> ( a %ort circuit4 ,x mu/ be borne 9 m9d t ea* complete circuit w require at lea/ two wires1 viz41 ! "o lead+ f ! batt]y to ! bell1 & ! o!r back f ! bell to ! batt]y2 & ^! until connection is made betwe5 !m by means ( ! contact 7pull1 pu%1 or key7 mu/ be p]fectly insulat$ f ea* o!r4 ,9 ^! cases1 z f> z possible1 ! wires %\ld be laid 9 slots cut 9 ! joi/s "u ! floor bo>ds1 or1 bett] /ill1 z t5d+ to weak5 ! joi/s less1 small holes may be bor$ 9 ! joi/s & ! wires pass$ ?r\gh !m2 or aga91 ! wires may be l$ along ! skirt+ bo>d1 along ! side ( ! doorpo/1 etc41 & :5 ! sight ( ! wires is objectionable1 cov]$ ) a light ornam5tal wood cas+4 ,:5 ! wires h be5 laid & ! position ( ! pu%es1 etc41 decid$ ^u1 ! blocks to :i* ^! are to be fa/5$ mu/ be b$d$ 9 ! pla/]4 ,^! blocks may be ei!r squ>e or circul> pieces ( elm1 ab\t #c in*es across1 & #a in* ?ick1 bevell$ (f small] above1 s z to be easily & firmly set 9 ! pla/]4 ,!y may be fa/5$ to ! brickwork by two or ?ree brads1 at su* a height to lie level ) ! f9i%$ pla/]4 ,!re mu/ ( c\rse be a hole 9 ! c5tre ( ! block1 ?r\gh :i* ! wires c pass to ! pu%4 ,:5 ! block has be5 fix$ 9 place1 ! z9c tube1 if x does n come q up to ! block1 %\ld h its orifice /opp$ ) a little pap]1 to prev5t any pla/]1 etc41 gett+ into ! tube4 ,a little c>e 9 sett+ ! block w avoid ! necessity ( ?is make%ift4 ,a long nail or screw driv5 into ! block w s]ve to m>k its place1 & save "t 9 hunt+ = x aft] ! pla/]+ has be5 done4 ,:5 ! blocks h be5 put 9 _! places1 & ! pla/]+1 pap]+1 etc41 done1 ! wires are drawn ?r\gh ! bottom hole ( ! pu% 7aft] ! lid or cov] has be5 tak5 (f71 ,fig4 #gd1 & a v small piece ( ! cov]+ ( ! wire hav+ be5 remov$ f ea* wire1 & bright5$ by s& pap]+1 "o piece is pass$ r\nd ! %ank ( ! screw connect$ ) ! l[] spr+1 %[n to ! "r 9 ,fig4 #gd1 & ! o!r r\nd ! %ank ( ! screw connect$ to ! upp] spr+1 %[n to ! left 9 ! ,fig4 ,! screws mu/ be loos5$ to enable ! op]ator to pass ! wire "u _! heads4 ,! screws mu/ !n be tight5$ up to cl5* ! wire q firmly4 ,9 do+ ?is1 we mu/ gu>d aga9/ ?ree ?+s4 ,fir/ly1 9 pull+ ! wire ?r\gh ! block1 n to pull s tightly z to cut ! cov]+ aga9/ ! edge ( ! z9c tube4 ,secondly1 n to uncov] too mu* ( ! wire1 s z to make contact betwe5 ! wires !mselves ei!r at ! back ( ! pu%1 or at any o!r "p ( ! pu% itself4 ,?irdly1 to secure good contact "u ! screws1 by hav+ ! ends ( ! wires q clean1 & tightly screw$ d[n4 ,illu/ration3 ,fig4 #gd4 ,s #fi4 ,9 all cases :]e ! wires h to be tak5 out ( doors1 su* z is necessitat$ by communication f h\se to ou?\ses1 /ables1 gre5h\ses1 etc41 ov] head l9es 7,no4 #ah gauge1 gutta-p]*a tape & t> cov]+7 %\ld be us$4 ,:]e ov]head l9es are n admissible1 ei!r z be+ eyesores1 or o!rwise1 ! wires may be laid 9 squ>e wood5 cas+s ( ?is section box op5 up1 ! op5 "p ( :i* mu/ be cov]$ by a /rip ( wood laid ov] x4 ,! wood mu/ h be5 previ\sly creosot$1 9 ! same mann] z railway sleep]s4 ,?is mode admits ( easy exam9ation4 ,iron pipes mu/1 h[ev]1 be us$ if ! l9es h to pass "u roads1 etc41 :]e !re is any heavy traffic4 ,& x mu/ be borne 9 m9d t h[ev] c>efully ! iron pipes1 etc41 be cem5t$ at ! jo9ts1 to make !m wat]tight1 !re w always be m electrical leakage 9 und]gr\nd l9es ?an 9 ov]head ones4 ,9 c]ta9 r>e cases x may be ne$ful to use iron wires = ?is purpose in/ead ( copp]2 9 ?is case1 z iron is six or sev5 times a worse conductor ?an copp]1 a mu* heavi] wire mu/ be employ$ to get ! same effect4 ,9 o!r words1 :]e iron wire is us$1 its section mu/ be n less ?an sev5 times t ( ! copp] wire :i* x replaces4 ,s #gj4 ,x is always pref]able1 :]e great di/ance 7&1 consequ5tly1 great] exp5se7 d n preclude x1 to use wire = ! lead+ z well z = ! return+ circuit4 ,/ill1 :]e = any reason ?is is n practicable1 x is p]fectly admissible & possible to make a good return circuit ?r\gh ! e>?1 t is to make ! damp soil c>ry ! return curr5t 7see ,s #cg74 ,z recomm5d$ at ! section j quot$1 ?is e>? circuit mu/ h at ea* extremity a mass ( "s good conductor plung$ into ! moi/ gr\nd4 ,9 t[ns1 :]e !re are pl5ty ( wat] ma9s & gas ma9s1 ?is is a matt] ( no difficulty1 ! only po9t be+ to ensure good contact ) ^! masses ( metal4 ,9 o!r places a hole mu/ be dug into ! gr\nd until ! po9t ( con/ant moi/ure is rea*$2 9 ?is mu/ be plac$ a %eet ( lead or copp]1 n less ?an five squ>e feet surface1 to :i* ! e>? wires are sold]$1 ! hole !n fill$ 9 ) ord9>y coke1 well ramm$ d[n to )9 ab\t six in*es ( ! surface1 & !n cov]$ up ) soil well trodd5 d[n4 ,9 mak+ contact ) wat] or gas pipes1 c>e mu/ be tak5 to see t ^! are ma9 pipes1 s t !y d lead to e>?1 & n to a ci/]n or met] only1 z1 if !re are any :ite or r$ lead jo9ts ! circuit w be defective4 ,to secure a good contact ) an iron pipe1 b>e x1 file its surface clean1 rub x ov] ) a bit ( blue /one 7sulphate ( copp]7 dipp$ 9 wat]2 wipe x q dry1 b9d x tightly & ev5ly r\nd ) "s b>e copp] wire 7also well clean$71 ,no4 #af gauge4 ,br+ ! two ends ( ! wire toge!r1 & twi/ !m up tightly = a l5g? ( ?ree or f\r in*es4 ,n[ heat a l>ge sold]+ bit1 put "s res9 on ! copp] wire1 & sold] ! wire1 b9d+ firmly d[n to ! iron pipe4 ,d likewise to ! project+ twi/ ( wire1 & to ?is twi/ sold] ! end ( ! return wire4 ,on no acc\nt %\ld ! two opposite e>? wires be sold]$ to wat] ma9s & gas ma9s at ! same "t1 s9ce x has be5 f\nd t ! diff]5t conditions 9 :i* ^! pipes f9d !mselves is suffici5t to set up a curr5t :i* might s]i\sly int]f]e ) ! work+ ( ! batt]y prop]4 ,sometimes !re is no means ( gett+ a good e>? except ?r\gh ! gas ma93 9 ?is case we mu/ be c>eful to get to ! /reet side ( ! met]1 = ! r$ lead jo9ts w prev5t good conductivity be+ obta9$4 ,9 out ( ! way c\ntry places1 if x is possible to get at ! metal pipe lead+ to ! well ( a pump1 a v good e>? c be obta9$ by sold]+ ! wires to t pipe1 9 ! same mann] z direct$ 9 ! case ( ! wat] ma94 ,! op]ator %\ld 9 no case be cont5t$ ) a m]ely twi/$ jo9t1 = ! m]e contact ( ! two metals 7copp] & iron7 sets up 9 ! moi/ e>? or air a little electric circuit ( its own1 & ?is spe$ily ru/s ?r\gh & de/roys ! wires4 ,! foll[+ sugge/ions1 by ,messrs4 ,g5t1 on ! subject ( wir+1 are s good1 t we feel t we %all be do+ real s]vice to ! read] to quote !m "h 9 full3-- #a/4--,! description ( wire to be us$4 ,x is ( ! utmo/ importance t all wires us$ = electric bell purposes be ( pure copp] & ?or\ghly well insulat$4 ,! mat]ials mo/ly employ$ = insulat+ purposes are indi>ubb]1 gutta-p]*a1 or cotton saturat$ ) p>aff94 ,= ord9>y indoor "w1 9 dry places1 & = connect+ doors & w9d[s ) burgl> al>ms1 or = signall+ 9 case ( fire1 indi>ubb] & cotton cov]$ wires answ] well2 b = connect+ long di/ances1 "p or all und]gr\nd1 or along walls1 or 9 damp cell>s or build+s1 gutta-p]*a cov]$ wire is requir$1 b x %\ld be fix$ :]e x w n be expos$ to heat or ! sun1 or 9 v dry places1 z ! cov]+ s expos$ w p]i%1 crack1 & 9 "t fall (f4 ,?is may be1 to "s ext5t1 prev5t$ by its be+ cov]$ ) cotton2 b we recomm5d = w>m or expos$ positions a specially-prep>$ wire1 9 :i* rubb] & comp\nd =m ! insulat+ mat]ials1 ! outside be+ braid$ or tap$4 ,= ord9>y h\se "w1 we ref] to lay a wire ( ,no4 #ah or #bj copp]1 cov]$ to ,no4 #ad or #aa ) gutta-p]*a1 & an out] cov]+ ( cotton1 :i* we call$ ! 'batt]y' wire1 ?is be+ ! wire :i* conveys ! curr5t f ! batt]y to e pu%1 etc41 no matt] h[ _m or 9 :at position4 ,! reason = select+ ?is k9d is1 t ) ! gutta-p]*a wires ! jo9ts may be m p]fectly cov]$ & made secure aga9/ damp4 ,?is is ( ! utmo/ importance 9 ! case ( 'batt]y wires1' z ! curr5t is always pres5t & ready to take advantage ( any defect 9 ! insulation to escape to an adjo9+ wire1 or to 'e>?1' & s cause a cont9u\s wa/e ( curr5t4 ,! wires lead+ f ! pu%es to ! signall+ app>atus or bell we call ! 'l9e' wires4 ,9 ^!1 & ! re/ ( ! h\se wires1 ! p]fect cov]+ ( ! jo9ts is important4 ,= l9e wires we usually pref] ,no4 #ah or #bj copp]1 cov]$ ) indi>ubb]1 & an out] coat+ ( cotton1 well v>ni%$4 ,9 jo9+ ! 'batt]y wires1' ! place :]e ! junction is to be made mu/ be c>efully uncov]$ = ! di/ance ( ab\t an in*2 ! ends ( ! wire to be jo9$1 well clean$1 & tightly twi/$ toge!r2 ) ! flame ( a _s lamp or c&le ! jo9t mu/ be !n heat$ suffici5tly to melt f9e sold] 9 /rips :5 held ^u x1 hav+ fir/ put a little p[d]$ res9 on ! jo9t z a flux2 ! sold] %\ld be se5 to run well & adh]e firmly to ! copp] wire4 ,a piece ( gutta-p]*a %\ld !n be tak5 & plac$ ^u ! jo9t :ile w>m1 & ) ! aid ( ! _s lamp & wet f+]s1 m\ld$ r\nd until a firm & p]fect cov]+ has be5 =m$4 ,on no acc\nt use spirits 9 sold]+4 ,) ! l9e wire1 x is be/1 z f> z possible1 to convey x all ! way f ! pu% to ! signal box or bell 9 "o cont9u\s l5g?4 ,( c\rse1 :5 two or m pu%es are requir$ to ! same wire1 a junction is unavoidable4 ,! same process ( jo9+ & cov]+1 z giv5 = ! batt]y wire1 applies to ! l9e wire4 ,:]e _m wires are to be br\ght d[n to "o position1 a l>ge tube may be buri$ 9 ! wall1 or a wood cas+ fix$ flu% ) ! pla/]1 ) a removable front4 ,! latt] plan is easie/ = fix+ & = mak+ alt]ations & additions4 ,= /apl+ ! wires1 9 no case %\ld ! wires be left nak$4 ,:5 !y pass along a damp wall1 x is be/ to fix a bo>d & loosely /aple !m4 ,9 no case all[ m ?an "o wire to lie "u ! same /aple1 & d n let ! /aples t\* "o ano!r4 ,9 _m cases1 electric bells h be5 an incessant annoyance & complete failure1 ?r\gh driv+ ! /aples tight up to ! wires1 & sev]al wires to ! same /aple1--?is mu/ n be done on any acc\nt4 ,a numb] ( wires may be twi/$ into a cable1 & run ?r\gh a %ort piece ( gutta-p]*a tube1 & fa/5$ ) ord9>y gas hooks :]e x is an advantage to d s4 ,9 runn+ ! wires1 avoid hot wat] pipes1 & d n take !m along ! same way z plumb] pipes4 ,und]gr\nd wires mu/ be laid betwe5 pieces ( wood1 or 9 a gas or dra9 pipe1 & n expos$ 9 ! b>e e>? )\t protection1 z %>p pieces ( /one are apt to p5etrate ! cov]+ & cause a loss2 9 fact1 9 ?is1 z 9 e "p ( fix+ wires1 ! be/ wire & ! be/ protection is by f> ! *eape/ 9 ! end4 ,! copp] wire 9 ?is case %\ld n be less ?an ,no4 #af ,b4,w4,g41 cov]$ ) gutta-p]*a1 to ,no4 #i or #aj ,b4,w4,g41 & pref]ably an out] cov]+ ( tape or braid well t>r$4 ,outside wire1 :5 run along walls & expos$ to ! wea!r1 %\ld be cov]$ ) rubb] & comp\nd1 & v>ni%$ or t>r$ on an out] cov]+ ( tape or braid4 ,hooks or /aples mu/ be well galvanis$ to prev5t ru/+1 & fix$ loosely4 ,if ! wire is conta9$ )9 an iron pipe1 a light] insulation may be us$3 b ! pipe mu/ be wat]tight4 ,9 a new build+1 wires mu/ be conta9$ )9 z9c or copp] bell tubes4 ,a #c_/h in* tube w hold two wires com=tably4 ,! tubes %\ld be fix$ to t]m9ate 9 ! same positions 9 ! rooms z ord9>y crank bell lev]s1--t is1 ab\t ?ree feet f ! floor4 ,at ! side ( ! fireplace a block ( wood %\ld be fix$ 9 ! wall be=e any pla/] is put on1 & ! end ( ! tube %\ld t]m9ate 9 ! c5tre ( ! same4 ,a l>ge nail or screw may be put 9 to m>k ! place1 s t ! end ( ! tube may be f\nd easily :5 ! pla/]+ is f9i%$4 ,b5d ! tube slightly =w>d at ! end1 & ins]t a %ort peg ( wood to prev5t dirt gett+ into ! tube4 ,d ! same at ! side (1 or ov] ! b$ 9 b$room4 ,if ! tubes are kept clean1 ! wires may be easily drawn up or d[n z ! case may require4 ,! be/ way is to get a l5g? ( ord9>y copp] bell wire1 ,no4 #af1 suffici5t to pass ?r\gh ! tube1 & hav+ /ret*$ x1 pass x ?r\gh & out at ! o!r end4 ,"h h y\r coils ( insulat$ wire1 viz41 "o batt]y wire1 :i* is bran*$ (f to e pu%1 & "o l9e wire1 :i* has to g direct to ! indicator or bells1 & hav+ remov$ a %ort portion ( ! insulation f ! end ( ea*1 !y are ti$ to ! b>e copp] wire & drawn ?r\gh4 ,?is is repeat$ :]ev] a pu% is to be fix$ ?r\gh\t ! build+4 ,9 mak+ connection ) b9d+ screws or metal ( any k9d1 x is ( ! utmo/ importance t ev]y?+ %\ld be p]fectly clean4 ,jo9ts 9 wire1 :e!r t9n$ or unt9n$1 mu/ be sold]$ & cov]$4 ,we _c impress ?is too e>ne/ly on fix]s4 ,nev] bury wires 9 pla/] unprotect$1 & 9 h\ses 9 c\rse ( erection1 ! tubes only %\ld be fix$ until ! pla/]+ is f9i%$1 ! wires to be run 9 at ! same "t t ! o!r "w is complet$4 ,illu/ration3 ,fig4 #ge4 ,s #ga4 ,! wires hav+ be5 laid by any ( ! me?ods indicat$ 9 ! prec$+ five sections1 ! fix] is n[ 9 a position to connect up4 ,no two h\ses or (fices w admit ( ?is be+ done 9 exactly ! same way2 b 9 ! foll[+ sections mo/ ( ! possible cases are describ$ & illu/rat$1 & ! intellig5t fix] w f9d no difficulty1 :5 he has once grasp$ ! pr9ciple1 9 mak+ ^? trifl+ modifications :i* ! p>ticul> requirem5ts may r5d] necess>y4 ,! fir/ & simple/ =m1 :i* engages our att5tion1 is t ( a s+le bell1 batt]y1 & pu%1 connect$ by wire only4 ,?is is illu/rat$ at ,fig4 #ge4 ,"h we see t ! bell is connect$ by means ( "o ( ! wires to ! z9c pole ( ! batt]y1 ! pu% or o!r contact be+ connect$ to ! c>bon pole ( ! same batt]y4 ,a second wire unites ! o!r screw ( ! pu% or contact ) ! second b9d+ screw ( ! bell4 ,!re is no complete circuit until ! pu% is press$1 :5 ! curr5t circulates f ! c>bon or positive pole ( ! batt]y1 ?r\gh ! contact spr+s ( ! pu%1 along ! wire to ! bell1 & !n back aga9 ?r\gh ! "u wire to ! z9c or negative pole ( ! batt]y4#ae ,x mu/ be cle>ly und]/ood t ! exact position ( batt]y1 bell1 & pu% is q immat]ial4 ,:at is ess5tial is1 t ! relative connections betwe5 batt]y1 bell1 & pu% be ma9ta9$ unalt]$4 ,fig4 #gf %[s ! next simple/ case1 viz41 t 9 :i* a s+le bell & pu% are work$ by a s+le cell ?r\gh an e>? return 7see ,s #gj74 ,"h ! curr5t is made to pass f ! c>bon pole ( ! batt]y to ! pu%1 !nce along ! l9e wire to ! bell4 ,aft] pass+ ?r\gh ! bell1 x goes to ! "r-h& e>?-plate ,e1 pass+ ?r\gh ! soil till x rea*es ! left-h& e>?-plate ,e1 !nce back to ! z9c pole ( ! batt]y4 ,x is ( no consequ5ce to ! work+ ( ! bell :e!r ! batt]y be plac$ betwe5 ! pu% & ! left-h& e>?-plate1 or betwe5 ! bell & ! "r-h& e>?-plate2 inde$1 "s op]ators pref] to keep ! batt]y z ne> to ! bell z possible4 ,at ,fig4 #gg is %[n ! mode by :i* a s+le batt]y & s+le bell c be made to r+ f two 7or m7 pu%es situat$ 9 diff]5t rooms4 ,"h x is evid5t t1 :i*ev] ( ! two pu%es be press$1 ! curr5t f9ds its way to ! bell by ! upp] wire1 & back home aga9 ?r\gh ! l[] wire2 &1 ev5 if bo? pu%es are d[n at once1 ! bell r+s j ! same1 = bo? pu%es lead f ! same pole ( ! batt]y 7! c>bon7 to ! same wire 7! l9e wire74 ,footnote #ae3 ,x mu/ be borne 9 m9d t ! negative elem5t is t to :i* ! positive pole is atta*$1 & vice v]sa 7see ss4 #h & #i74 ,illu/ration3 ,fig4 #gf4 ,illu/ration3 ,fig4 #gg4 ,9 ,fig4 #gh1 we h a slight modification ( ! same arrangem5t1 a front-door pull contact be+ ins]t$ 9 ! circuit2 & "h1 9 view ( ! probably increas$ resi/ance ( long] di/ance1 two cells are suppos$ to be employ$ in/ead ( "o1 & ^! are c\pl$ up 9 s]ies 7,s #dj71 9 ord] to ov]come ?is increas$ resi/ance4 ,illu/ration3 ,fig4 #gh4 ,! next case :i* may occur is :]e x is desir$ to r+ two or m bells f "o pu%4 ,!re are two mann]s ( do+ ?is4 ,! fir/ mode is to make ! curr5t divide itself betwe5 ! two bells1 :i* are !n said to be 9 p>allel4 ,?is mode is well illu/rat$ bo? at ,figs4 #gi & #hj4 ,z 9 ^! cases ! curr5t has to divide itself among ! bells1 l>g] cells mu/ be us$1 to provide = ! l>g] dem&2 or sev]al cells may be c\pl$ up 9 p>allel 7,s #dj74 ,at ,fig4 #gi is %[n ! arrangem5t = two adjo9+ rooms2 at ,fig4 #hj1 t to be adopt$ :5 ! rooms are at "s di/ance ap>t4 ,if1 z %[n at ,fig4 #ha1 a swit* simil> to t figur$ 9 ! cut ,fig4 #fd be ins]t$ at ! po9t :]e ! l9e wires conv]ge to meet ! pu%1 x is possible = ! p]son us+ ! pu% to r+ bo? bells at once1 or to r+ ei!r ! "r-h& or ! left-h& bell at w1 accord+ to :e!r he turns ! arm ( ! swit*-lev] on to ! "r-h& or left-h& contact plate4 ,illu/ration3 ,fig4 #gi4 ,illu/ration3 ,fig4 #hj4 ,illu/ration3 ,fig4 #ha4 ,! second mode ( r++ two or m bells f "o pu% is t ( connect+ "o bell to ! o!r1 ! "r-h& b9d+ screw ( ! "o to ! left-h& b9d+ screw ( ! next1 & s on1 & !n connect+ up ! :ole s]ies ( bells to ! pu% & batt]y1 z if !y 7 a s+le bell4 ,?is mode ( dispos+ ! bells is call$ ! s]ies arrangem5t4 ,z we h already notic$ at ,s #fc1 ow+ to ! diff]5ce 9 ! times at :i* ! diff]5t contact spr+s ( ! v>i\s bells make contact1 ?is mode is n v satisfactory4 ,if ! bells are s+le /roke bells1 !y "w v well 9 s]ies2 b1 to get trembl+ bells to "w 9 s]ies1 x is be/ to adopt ! =m ( bell recomm5d$ by ,mr4 ,f4 ,c4 ,allsop4 ,he says3 ,p]haps ! be/ plan is to use ! =m ( bell %[n at ,fig4 #hb1 :i*1 z w be se5 f ! figure1 gov]ns its vibrations1 n by break+ ! circuit1 b by %unt+ its coils4 ,on ! curr5t fl[+ r\nd ! electro-magnet1 ! armature is attract$1 & ! spr+ makes contact ) ! l[] screw4 ,!re n[ exi/s a pa? ( practically no resi/ance f end to end4 ,! curr5t is !re=e div]t$ f ! magnet coils1 & passes by ! armature & l[] screw to ! next bell1 ! armature fall+ back aga9/ ! top screw1 & repeat+ ! previ\s op]ation s long z ! circuit is clos$4 ,?us1 no matt] h[ _m bells !re be 9 ! s]ies1 ! circuit is nev] brok54 ,?is =m ( bell1 h[ev]1 does n r+ s en]getically z ! ord9>y =m1 ) a correspond+ am\nt ( batt]y p[]4 ,illu/ration3 ,fig4 #hb4 ,illu/ration3 ,fig4 #hc4 ,fig4 #hc illu/rates ! mode 9 :i* a bell1 at a long di/ance1 mu/ be c\pl$ up to "w ) a local batt]y & relay4 ,! relay is n %[n sep>ately1 b is suppos$ to be enclos$ 9 ! bell case4 ,"h1 on press+ ! pu% at ! ext]nal left-h& corn]1 ! batt]y curr5t passes into ! relay at ! di/ant /ation1 & out at ! "r-h& e>?-plate ,e return+ to ! left-h& e>?-plate ,e4 ,9 do+ ?is1 x ?r[s 9 circuit 7j z long z ! pu% is held d[n7 ! "r-h& local batt]y1 s t ! bell r+s by ! curr5t s5t by ! local batt]y1 ! m delicate relay work+ by ! curr5t s5t f ! di/ant batt]y4 ,illu/ration3 ,fig4 #hd4 ,illu/ration3 ,fig4 #he4 ,at ,fig4 #hd1 we h illu/rat$ ! mode ( connect+ up a cont9u\s r++ bell1 ) a wire return4 ,( c\rse1 if ! di/ance is great1 or a roadway1 etc41 int]v5e1 an ov]head l9e & an e>? plate may replace ! l9es %[n !re91 or bo? l9es may be buri$4 ,x is possible1 by us+ a ,morse key 7,fig4 #fe7 con/ruct$ s z to make contact 9 "o direction :5 n press$ d[n1 & 9 ! o!r :5 press$ d[n1 to signal f ei!r end ( a circuit1 us+ only "o l9e wire & "o return4 ,! mode ( connect+ up = ?is purpose is %[n at ,fig4 #he4 ,at ea* end we h a batt]y & bell1 ) a d\ble contact ,morse key z %[n1 ! ,morse key at ea* end be+ connect$ ?r\gh ! int]v5tion ( ! l9e wire ?r\gh ! c5tral /ud4 ,! batt]ies & bells at ea* /ation are connect$ to e>? plates1 z %[n4 ,suppose n[ we depress ! ,morse key at ! "r-h& /ation4 ,s9ce by s do+1 we lift ! back end ( ! lev]1 we ?r[ our own bell out ( circuit1 b make contact betwe5 our batt]y & ! l9e wire4 ,!re=e ! curr5t trav]ses ! l9e wire1 ent]s 9 ! left-h& ,morse key1 &1 s9ce ?is is n depress$1 c1 & does1 pass into ! bell1 :i* !re=e r+s1 !n desc5ds to ! left-h& e>?-plate1 return+ along ! gr\nd to ! batt]y f :5ce x />t$ at ! "r-h& ,e4 ,if1 on ! contr>y1 ! left-h& ,morse key be depress$1 :ile ! "r-h& key is n be+ manipulat$1 ! curr5t trav]ses 9 ! opposite direction1 & ! "r-h& bell r+s4 ,in/ead ( ,morse keys1 d\ble contact pu%es 7t is1 pu%es mak+ contact 9 "o direction :5 n press$1 & 9 ! opposite :5 press$7 may advantage\sly be employ$4 ,?is latt] arrangem5t is %[n at ,fig4 #hf4 ,illu/ration3 ,fig4 #hf4 ,x is also possible1 z %[n at ,fig4 #hg1 to s5d signals f two /ations1 us+ b "o batt]y 7:i*1 if ! di/ance is great1 %\ld be ( a proportionate numb] ( cells71 two bells1 & two ord9>y pu%es4 ,?ree wires1 besides ! e>?-plate or return wire1 are requir$ 9 ?is case4 ,! :ole ( ! wires1 except ! return1 mu/ be c>efully insulat$4 ,suppose 9 ?is case we press ! "r-h& button4 ,! curr5t fl[s f ! batt]y along ! l[] wire ?r\gh ?is "r-h& pu% & returns to ! di/ant bell along ! top wire1 d[n ! left-h& dott$ wire back to ! batt]y1 s9ce x _c ent] by ! left-h& press1 :i*1 n be+ pu%$1 makes no contact4 ,! left-h& bell !re=e r+s4 ,if1 on ! o!r h&1 ! left-h& pu% be press$1 ! curr5t f ! c>bon ( ! batt]y passes ?r\gh ! left-h& pu%1 trav]ses ! c5tral l9e wire1 passes into ! bell1 r+s x1 & desc5ds to ! "r-h& e>? plate ,e1 trav]ses ! e>? circuit till x rea*es ! left-h& e>? plate ,e1 :5ce x returns to ! z9c pole ( ! batt]y by ! l[] dott$ l9e4 ,illu/ration3 ,fig4 #hg4 ,fig4 #hh %[s h[ ! same result 7signall+ 9 bo? directions7 may be atta9$1 us+ only two wires1 ) e>? return1 & two ,morse keys4 ,! direction ( ! curr5t is %[n by ! arr[s4 ,bo? wires mu/ be insulat$ & ei!r c>ri$ ov]head or und]gr\nd1 buri$ 9 tubes4 ,fig4 #hi %[s ! prop] mode ( connect+ ! entire sy/em ( bells1 pu%es1 etc41 runn+ ?r\gh a build+4 ,! dott$ l9es are ! wires />t+ f ! two poles ( ! batt]y 7:i* %\ld consi/ ( m cells 9 proportion z !re is m "w to d71 ! pla9 l9es be+ ! wires betwe5 ! pu%es & ! bell & signall+ box4 ,9 ?is illu/ration a door-pull is %[n to ! extreme left4 ,p5dulum indicators are usually connect$ up z %[n 9 ?is figure1 except t ! bell is g5]ally enclos$ 9 ! indicator case4 ,! wire1 !re=e1 has to be c>ri$ f ! left-h& screw ( ! indicator case direct to ! upp] dott$ l9e1 :i* is ! wire return+ to ! z9c pole ( ! batt]y4 ,n4,b4--,:5 ! wires f ! press-buttons are connect$ ) ! b9d+-screw1 ( ! top ( or inside ( ! indicator case1 ! insulat+ mat]ial ( ! wires1 at ! po9t :]e connection is to be made1 mu/ be remov$1 & ! wires c>efully clean$ & tightly clamp$ d[n4 ,illu/ration3 ,fig4 #hh4 ,illu/ration3 ,fig4 #hi4 ,:5 x is desir$ to connect sep>ate bells to r+ 9 o!r p>ts ( ! build+1 ! quicke/ way is to take a bran* wire out ( ! ne>e/ batt]y wire 7! wire com+ f ! c>bon pole71 & c>ry x to ! pu% or pull1 f !nce to ! bell1 & f ! bell back to ! z9c ( ! batt]y4 ,s #gb4 ,we %\ld advise ! fix] always to draw out a little sket* ( ! arrangem5t he int5ds to adopt 9 c>ry+ out any plan1 z any means ( sav+ useless l5g?s ( wire1 etc41 w !n easily be se54 ,9 do+ ?is1 in/ead ( mak+ full sket*es ( batt]ies1 he may use ! conv5tional signs batt]y = ea* cell ( ! batt]y1 ! ?ick /roke mean+ ! c>bon1 ! ?9 "o ! z9c4 ,pu%es may be repres5t$ by 7471 e>?-plates by ,e & pulls1 swit*es1 c41 z %[n 9 ! annex$ cut1 ,fig4 #ij1 :i* illu/rates a mode ( connect+ up a lodge ) a h\se1 cont9u\s bells be+ us$1 9 su* a way t ! lodge bell c be made to r+ f ! lodge pull1 ! h\se bell r++ or n1 accord+ to ! way ! swit* 7%[n at top left-h& corn]7 is set4 ,z x is set 9 ! engrav+1 only ! lodge bell r+s4 ,illu/ration3 ,fig4 #ij4 ,s #gc4 ,!re are /ill two cases ( electric bell & signal fitt+1 to :i* att5tion mu/ be direct$4 ,! fir/ is 9 ! case ( %ips4 ,"h all ! connections c be made exactly z 9 a h\se1 ! only exception to be made be+ t ! indicators mu/ n be ( ! p5dulum1 or o!r easily displac$ type2 b ei!r ( ! =m %[n at ,fig4 #fg or #fh1 9 :i* ! electro-magnet has to lift a lat* to release ! fall or drop1 aga9/ a pretty /iff spr+4 ,besides be+ ?us firmly lock+1 s z n to be affect$ by ! %ip's motion1 all ! wood "w %\ld be soak$ 9 melt$ p>aff9 wax1 ! iron "w japann$1 & ! brass "w well lacqu]$1 to protect all p>ts f damp4 ,! second case requir+ notice is t ( lifts4 ,e well-appo9t$ lift %\ld be fitt$ ) electric bells & indicators4 ,9 ! cab ( ! lift itself %\ld be plac$ an electric bell1 ) z _m d\ble contact pu%es & indicators z !re are floors to be communicat$ )4 ,at ! top & at ! bottom ( ! left %aft1 z ne> to ! l&+ side z possible1 mu/ be set two /\t wood5 blocks 7oak1 elm1 or o!r non-p]i%able wood74 ,f top to bottom ( ! %aft mu/ !n be /ret*$1 9 ! same mann] z a pian(orte is /rung1 on /\t metal p9s1 ) ?read+ holes & squ>e heads1 z _m ,no4 #ab or #ad b>e copp] wires z !re are floors or l&+s1 & two m = ! batt]y & return wire respectively4 ,c>e mu/ be tak5 t ^! wires are /rung p]fectly p>allel1 & t !y are /ret*$ q taut1 b n /ra9$1 o!rwise !y w surely break4 ,to ! top ( ! cab1 & 9 connection 9 ! usual mann] by wires ) ! bell & indicator 7:i*1 z 9 ! case ( %ips1 mu/ be ( ! lock+ type1 le/ ! jolts ( ! cab di/urb _! action7 mu/ be atta*$ a numb] ( spoonbill spr+s1 :i* press aga9/ ! nak$ wires runn+ d[n ! %aft4 ,! %ape ( ^! spr+s 7:i* %\ld be ( brass7 at ! "p :]e !y press aga9/ ! b>e wires1 is simil> to t ( ! spoon break ( a bicycle4 ,"s op]ators use roll]s at ! end ( ! spr+ in/ead ( spoonbills1 b ^! latt] rub ! wires & keep up good contact1 :ile ! roll]s slip ov] ! wires & d n keep !m clean4 ,by means ( ^! spr+s1 ! curr5t f ! batt]ies1 :i* are be/ plac$ ei!r at ! top ( ! lift itself1 or 9 "o ( ! adjac5t rooms 7nev] at ! bottom ( ! %aft1 ow+ to ! damp :i* always reigns !re71 c be tak5 (f & direct$ :]e x is desir$1 precisely z if ! batt]ies 7 9 ! cab itself4 ,x is usual 7?\gh n obligatory7 to use ! two wires fur!/ f ! l&+ z ! g & return batt]y wires1 & f ^!1 ?r\gh ! o!r wires1 all desir$ communication ) ! l&+s c be effect$4 ,to obta9 ?is end1 x w be necess>y to furni% e l&+ ) a d\ble contact pu% & bell1 & ea* bell & pu% mu/ be connect$ up to ! %aft wires 9 ! foll[+ mode3-- ,a wire mu/ be l$ f ! l[] contact spr+ ( ! d\ble contact pu%1 to ! ma9 batt]y c>bon wire 9 ! %aft4 ,a second wire is l$ f ! upp] contact /op ( ! d\ble contact pu% to ! bell1 & !nce to ! ma9 batt]y z9c wire on ! %aft4 ,la/ly1 a ?ird wire is tak5 f ! upp] contact spr+ ( ! pu% & connect$ to t p>ticul> wire 9 ! %aft :i* by means ( ! spoonbill spr+s connects ! p>ticul> pu% & indicator 9 ! cab1 de/9$ to correspond ) x4 ,x w be se5 t ) ! exception ( us+ ! rubb+ spoonbill spr+s & return wires 9 ! %aft1 ?is arrangem5t is simil> to t illu/rat$ at ,fig4 #hg4 ,illu/ration3 ,fig4 #ia4 ,a glance at ,fig4 #ia w r5d] ! :ole sy/em ( wir+ & connect+ up ) lifts & l&+1 p]fectly cle>4 ,9 connect+ ! bran* l9es to ! ma9 b>e copp] wires 9 ! %aft1 9 ord] t ! spoonbill spr+s %\ld n int]f]e ) !m1 !y 7! ends ( ! bran* wires7 mu/ be b5t at "r angles1 l a lett] ,l1 & ! upright portion sold]$ neatly to ! back ( ! %aft wire4 ,any sold] :i* may fl[ ov] to ! front ( ! wire mu/ be c>efully scrap$ (f to prev5t any bumps affect+ ! smoo? work+ ( ! contact spr+s4 ,x w be evid5t on exam9ation ( ,fig4 #ia1 t if any ( ! pu%es on ! l&+s be press$1 ! circuit is complet$ betwe5 ! batt]y at ! top1 ?r\gh ! two batt]y wires to ! bell & "o ( ! indicators to ! cab1 &1 on ! o!r h&1 t if a pu% be press$ 9 ! cab1 a correspond+ bell on ! l&+ w be rung1 precisely z 9 ,fig4 #hg4 ,"s fitt]s employ a _m-/r&$ cable to convey ! curr5t to & f ! batt]y to ! cab & l&+1 in/ead ( ! sy/em ( /ret*$ wires h]e9 recomm5d$2 b ?is practice _c be advocat$1 z ! cont9ual b5d+ & unb5d+ ( ?is cable1 repeat$ s frequ5tly e day1 soon breaks ! lead+ wires conta9$ 9 ! cable4 ,s #gd4 ,9 _m cases :]e a call bell alone is requir$1 ! batt]y may be entirely disp5s$ )1 & a small dynamo 7,s #ae7 employ$ in/ead4 ,! entire app>atus is !n kn[n z ! magneto-bell1 & consi/s ess5tially ( two p>ts1 viz41 ! g5]ator1 ,fig4 #ib1 & ! bell1 ,fig4 #ic4 ,! g5]ator or inductor consi/s ( an armature1 :i* by means ( a project+ h&le & tra9 ( :eels c be revolv$ rapidly betwe5 ! poles ( a p[]ful magnet2 ! :ole be+ enclos$ 9 a box4 ,! curr5t produc$ by ! revolution ( ! armature is l$ to ! two b9d+ screws at ! top ( ! box4 ,by means ( two wires1 or "o wire & an e>? circuit1 ! curr5t is l$ to ! receiv] or bell case1 ,fig4 #ic4 ,"h1 !re are usually two bells1 plac$ v ne> "o ano!r1 & ! armature atta*$ to ! bell clapp] is s arrang$ betwe5 ! poles ( ! d\ble-bell magnets1 t x /rikes alt]nately ! "o & ! o!r1 s t a cle> r++ is kept up z long z ! h&le is be+ turn$ at ! g5]ator4 ,illu/ration3 ,fig4 #ib4 ,illu/ration3 ,fig4 #ic4 ,illu/ration3 ,fig4 #id4 ,if a comb9$ g5]ator & bell be fitt$ at ea* end ( a l9e1 x becomes possible to communicate bo? ways2 "o t]m9al ( ea* in/rum5t mu/ be connect$ to ! l9e1 & ! o!r t]m9al on ea* to e>?4 ,a comb9$ g5]ator & bell is %[n at ,fig4 #id4 ,^! in/rum5ts are always ready = use1 require no batt]y or press-buttons4 ,! g5]ator1 ,fig4 #ib1 w r+ sev5 bells simultane\sly1 if requir$1 s p[]ful is ! curr5t set up2 & by us+ a swit* any numb] ( bells1 plac$ 9 diff]5t positions1 c be rung1 by c>ry+ a sep>ate wire f ! swit* to ! bell4 ,illu/ration3 ,fig4 #ie4 ,s #ge4 ,our "w w\ld n be complete unless we po9t$ out ! means necess>y to detect faults 9 our "w4 ,9 ord] to localise faults1 two ?+s are requisite3 fir/1 a means ( kn[+ :e!r ! batt]y itself is work+ prop]ly1 t is to say1 giv+ ! due am\nt ( curr5t ( ! "r pressure1 or ,e4,m4,f42 secondly1 a means ( detect+ :e!r !re is leakage1 or loss ( curr5t1 or break ( circuit 9 our l9es4 ,=tunately1 ! means ( asc]ta9+ ^! data c be all comb9$ 9 "o in/rum5t1 kn[n z a l9esman's galvanomet] or detector1 ( :i* we give an illu/ration at ,fig4 #ie4 ,x w be rememb]$ 7,s #aj7 t if a curr5t be pass$ ov] or "u a pois$ magnetic ne$le1 p>allel to x1 ! ne$le is imm$iately deflect$ out ( ! p>allel l9e1 & sw+s r\nd to ! "r or left ( ! curr5t1 accord+ to ! direction ( ! curr5t2 likewise t ! ne$le is deflect$ f>!r f ! orig9al position z ! curr5t becomes /rong]4 ,! deflections1 h[ev]1 are n proportionate to ! /r5g? ( ! curr5t1 be+ fairly s up to ab\t #be to #cj degrees ( arc out ( ! orig9al position1 b be+ v mu* less ?an proportionate to ! curr5t /r5g? z ! ne$le gets f>!r f ! l9e ( curr5t2 s t a curr5t ( inf9ite /r5g? w\ld be requir$ to s5d ! ne$le up to #ij deg4 ,on ?is pr9ciple ! detector is con/ruct$4 ,x consi/s ( a loz5ge-%ap$ magnetic ne$le1 susp5d$ v]tically on a light sp9dle1 c>ry+ at "o end a po9t]1 :i* indicates on a c>d1 or metal dial1 ! deflection ( ! ne$le4 ,beh9d ! dial is arrang$ a flat upright coil ( wire 7or two coils 9 _m cases7 p>allel to ! ne$le1 along :i* ! curr5t to be te/$ c be s5t4 ,! ne$le lies betwe5 ! front & back ( ! flat coil4 ,! :ole is enclos$ 9 a neat wood5 box1 ) glaz$ front to %[ ! dial1 & b9d+ screws to connect up to ! enclos$ coil or coils4 ,if ! coil surr\nd+ ! ne$le be ( a few turns ( co>se wire1 s9ce x opposes little resi/ance to ! passage ( ! curr5t1 x w s]ve to detect ! pres5ce ( l>ge quantities ( electricity 7_m ampe'res7 at a l[ pressure2 ?is is call$ a quantity coil4 ,if1 on ! o!r h&1 ! coil be "o ( f9e wire1 9 _m convolutions1 z x requires m pressure1 or ,e4,m4,f41 or int5sity to =ce ! curr5t ?r\gh ! f9e high-resi/ance wire1 ! in/rum5t becomes "o fitt$ to measure ! voltage or pressure ( ! curr5t1 & ! coil is kn[n z ! int5sity4 ,if bo? coils are ins]t$ 9 ! case1 s t ei!r c be us$ at w1 ! in/rum5t is capable ( measur+ ei!r ! quantity ( electricity pass+1 or ! pressure at :i* x is s5t1 & is !n kn[n z a quantity & int5sity detector4 ,no two galvanomet]s give exactly ! same deflection = ! same am\nt ( curr5t1 or ! same pressure2 ! fitt] w !re=e d well to run out a little table 7:i* he w soon le>n by he>t7 ( ! deflection 8 in/rum5t gives ) #a1 #b1 #c1 #d1 #e & #f ,leclan*'e's c\pl$ 9 p>allel1 :5 connect$ ) ! quantity coil4 ,he w f9d ! small] sizes give less curr5t ?an ! l>g] ones4 ,9 te/+ ! deflections giv5 by ! int5sity coil1 he mu/ rememb] to c\ple 8 cells 9 s]ies1 z he w get no increase 9 t5sion or pressure by c\pl+ up 9 p>allel4 ,9 ei!r case ! cells %\ld be new1 & fre%ly set up1 say1 )9 #bd h\rs4 ,z "s ( my read]s may l to try _! skill at con/ruct+ su* a detector1 ,i transcribe ! directions giv5 9 ,amateur "w by ,mr4 ,edw9son3-- ,s #gf4 ,su* an in/rum5t1 suitable = detect+ ! curr5ts 9 an electric bell circuit1 may be made up at ! co/ ( a few %ill+s = mat]ial1 & by ! ex]cise ( a little con/ructive ability4 ,we %all ne$1 fir/ ( all1 a magnetis$ ne$le2 ?is c be made out ( a piece ( wat* spr+4 ,procure a piece ( wat* spr+ two in*es long1 s(t5 x by heat+ x to r$ness1 & all[+ x to cool gradually 9 a b$ ( hot a%es2 !n file x up to ! =m ( a long loz5ge1 drill a small hole 9 ! c5tre to receive ! sp9dle or pivot1 see t ! ne$le is q /raight1 !n h>d5 x by heat+ x aga9 to a bright r$ & plung+ x at once into cold wat]4 ,x n[ has to be magnetis$4 ,to d ?is1 rub x on a p]man5t horse-%oe1 or o!r magnet1 until x w attract an ord9>y sew+ ne$le /rongly1 or wrap x up 9 sev]al turns ( insulat$ l9e wire1 & s5d _m j]ky *>ges ( electricity f a /rong batt]y ?r\gh ! wire4 ,:5 x has be5 well magnetis$1 m\nt x on a sp9dle ( f9e h>d wire1 & secure x by a drop ( sold]4 ,we w next turn our att5tion to ! case1 bobb91 or *amb] 9 :i* ! ne$le has to "w4 ,?is may be made out ( c>dbo>d entirely1 or ! end pieces may be made ( ivory or ebonite1 or x may be made out ( ?9 %eet brass2 = our purpose we w *oose c>dbo>d4 ,procure a piece ( /\t c>dbo>d #d-c_/d in*es long by #b in*es wide1 d\ble x to ! =m ( a ,t3and/ickor mat*-box1 & pi]ce x 9 exactly opposite sides1 & 9 ! c5tre ( ^? sides ) holes = ! ne$le sp9dle4 ,n[ cut ano!r piece ( /\t1 /iff c>dbo>d #b-c_/d in*es long by #c_/d in* wide1 & cut a slit ) a %>p knife to exactly fit ! ends ( ! case or body already prep>$4 ,! sp9dle holes mu/ n[ be bu%$ ) %ort l5g?s ( h>d brass or glass bugles1 or tub+1 made to all[ ! sp9dle free movem5t1 & ^! secur$ 9 position by a little melt$ %ellac1 seal+-wax1 or glue4 ,! ne$le mu/ n[ be plac$ 9 ! case1 ! long end ( ! sp9dle fir/1 !n ! %ort end 9 its be>+2 !n1 :il/ ! case ) ! ne$le enclos$ is held betwe5 ! f+] & ?umb ( ! left h&1 we secure ! jo9t ) a little glue or ) melt$ seal+-wax4 ,! end-pieces are n[ to be put on1 glu$1 or seal$ 9 position1 & set aside to get firm1 :il/ we turn our att5tion to o!r p>ts4 ,! case1 #e in*es by #d in*es by #b in*es 9 dep?1 may be improvis$ out ( an old cig>-box1 b is be/ made ( ?9 mahogany or teak1 nicely poli%$ on ! outside1 & fitt$ ) a cov] slid+ 9 a groove1 or h+$ to =m ! back ( ! in/rum5t4 ,! b9d+ screws %\ld be ( ! patt]n kn[n z ! telegraph patt]n1 fitt$ ) nuts1 %[n at ,fig4 #bg4 ,a small brass h&le to be fitt$ to ! top ( ! in/rum5t1 w also be h&y4 ,a circul> piece ( smoo? c>dbo>d #c-a_/d in*es 9 diamet]1 ) a graduat$ arc1 m>k$ z %[n 9 ,fig4 #ie1 w s]ve ! purpose ( a dial1 & a piece ( ?9 brass1 b5t to ! =m ( box op5 d[n1 w be requir$ z a ne$le gu>d4 ,! face ( ! dial may be a circul> piece ( glass1 held 9 a brass ogee1 or a hole ! size ( ! dial may be cut 9 a piece ( ?9 wood2 ?is1 glaz$ on ! inside ) a squ>e ( glass1 may be made to =m ! front ( ! in/rum5t ov] ! dial4 ,an indicat+ ne$le w also be requir$ = an outside ne$le2 ?is is usually made ( wat* spr+1 & nicely blu$2 b x may be made ( brass or any o!r metal1 "o made ( alum9ium be+ probably ! be/ on acc\nt ( its lightness4 ,x mu/ be pi]c$ ) a hole exactly 9 ! c5tre1 s z to balance x z ! beam ( scales %\ld be balanc$1 & %\ld "o end be heavi] ?an ! o!r x mu/ be fil$ until !y are equal4 ,we w n[ turn our att5tion to ! coil4 ,procure sixp5nywor? ( ,no4 #cf silk-cov]$ copp] wire & w9d ?ree lay]s ( x v ev5ly on ! coil case or bobb91 be+ c>eful 9 pass+ ! ne$le sp9dle n to p9* x or ?r[ x out ( tru?4 ,:5 ?is has be5 w\nd on1 x w be f\nd t "o end ( ! wire po9ts to ! left & ! o!r end to ! "r4 ,^! are de/9$ to be connect$ to ! "u side ( ! b9d+ screws %[n on ! top ( ,fig4 #ie4 ,we !re=e secure !m to _! respective sides ) a t\* ( seal+ wax1 & leave en\gh wire free at ! ends to rea* ! b9d+ screws--say1 ab\t #f in*es4 ,x is h&y to h an additional coil = te/+ /rong curr5ts1 & z ?is may be comb9$ 9 "o in/rum5t at a trifle additional co/1 we w get "s l9e wire 7,no4 #bb7 & w9d six or eight turns ( x ar\nd ! coil outside ! o!r wire2 "o end ( ?is wire w be atta*$ to an additional b9d+ screw plac$ betwe5 ! o!rs1 & ! o!r end to left b9d+ screw %[n4 ,! coil ?us prep>$ may n[ be m\nt$ 9 position4 ,pi]ce ! bo>d dial & ! wood at its back ) a hole l>ge en\gh = ! ne$le sp9dle to pass ?r\gh f ! back to ! c5tre ( ! dial4 ,see t ! ?ick end ( ! inside ne$le hangs d[nw>ds1 !n place ! coil 9 ! position x is int5d$ to occupy1 & note h[ f> ! ne$le sp9dle protrudes on ! face ( ! dial4 ,if ?is is too long1 nip (f ! end & file x up tap] & smoo? until x w "w freely 9 a hole 9 ! ne$le gu>d1 ) all p>ts 9 _! prop] places4 ,?is be+ satisfactory1 secure ! coil 9 its place by seal+ wax1 or1 bett] /ill1 by two ?9 /raps ( brass1 held by screws at ea* end1 plac$ across ! coil4 ,n[ clean ! free ends ( ! coil wires1 ins]t !m "u ! nuts ( ! b9d+ screws1 fix ! indicat+ ne$le on ! end ( ! sp9dle outside1 & see t x hangs 9 a v]tical position ) ! inside ne$le :5 ! in/rum5t is /&+ on a level surface4 ,secure x 9 ?is position1 screw on ! ne$le gu>d1 fa/5 on ! glass face1 & ! in/rum5t w be complete4 ,s #gg4 ,provid$ ?us ) an effici5t detector1 ! fitt] may proce$ to te/ 8 "w4 ,9 cases ( new in/allations1 take ! wire (f ! c>bon b9d+ screw ( ! batt]y & atta* x to "o screw ( ! galvanomet] 7on ! int5sity coil side71 next atta* a piece ( wire f ! o!r b9d+ screw ( ! galvanomet] 7! c5tral "o7 s z to place ! galvanomet] 9 circuit4 ,!re %\ld be no movem5t ( ! ne$le1 & 9 proportion to ! deflection ( ! ne$le1 s w ! loss or wa/e be4 ,if loss is go+ on1 e means mu/ be us$ to rem$y x4 ,x is ( ! utmo/ importance to ! effective work+ ( ! batt]y & bells t n ! slighte/ leakage or local action %\ld be all[$ to rema94 ,h[ev] slight su* loss may be1 x w ev5tually ru9 ! batt]y4 ,let damp places be s\ght out1 & ! wires remov$ f ne> !m4 ,bad or injur$ cov]+s mu/ also be look$ =1 su* z may h be5 caus$ by r\ghly draw+ ! wires across angul> walls1 tread+ on !m1 or driv+ /aples too tightly ov] !m4 ,two or m /aples may be t\*+1 or two or m wires c>elessly all[$ to lie "u "o /aple4 ,! wire may h be5 b>$ 9 "s places 9 pass+ ov] ! %>p edges ( ! z9c tube4 ,! backs ( ! pu%es %\ld be exam9$ to see if too mu* wire has be5 b>$1 & is t\*+ ano!r wire at ! back ( ! pu%-case itself4 ,or ! same ?+ may be tak+ place at ! junction ) ! relays or at ! indicator cases4 ,%\ld ! defect n be at any ( ^! places1 ! indicator %\ld next be exam9$1 & wire by wire deta*$ 7n cut7 until ! p>ticul> wire 9 :i* ! loss is go+ on has be5 f\nd4 ,?is wire %\ld !n be trac$ until ! defect has be5 discov]$4 ,9 te/+ und]gr\nd wires = a loss or break1 x w be necess>y fir/ to unc\ple ! di/ant end1 !n to disconnect ! o!r end f ! in/rum5ts1 & atta* ! wire go+ und]gr\nd to ! screw ( ! galvanomet]4 ,a piece ( wire mu/ !n be tak5 f ! o!r screw ( ! detector to ! c>bon end ( ! batt]y1 & a second wire f ! z9c end ( ! batt]y to ! e>? plate or o!r connection4 ,proce$+ to t "p ( ! wire :]e ! injury is suspect$1 ! wire is tak5 up1 & a tempor>y e>? connection hav+ be5 made 7wat] ma91 gas pipe1 etc471 & by means ( a %>p knife connect$ ) ?is latt]1 ! cov]+ ( ! suspect$ wire p5etrat$ ?r\gh to ! wire1 s z to make a good connection betwe5 ?is suspect$ wire & ! tempor>y e>? plates4 ,if1 :5 ?is is done1 ! ne$le is deflect$ fully1 ! injury is f>!r away f ! te/+ end1 & o!r trials mu/ be made f>!r on1 until ! spot is discov]$4 ,:]ev] ! cov]+ ( ! wire has be5 pi]c$ = te/+1 x mu/ be c>efully recov]$1 f9i%$ (f ) ,pr\t's ela/ic glue1 or gutta-p]*a1 & made q s\nd4 ,! connections ) ! e>? plates v frequ5tly give tr\ble1 ! wires corrode or become deta*$ f ! iron pipes etc41 & !n ! circuit is brok54 ,s #gh4 ,:5 ! fitt] is call$ to localise defects :i* may h occurr$ 9 an in/allation :i* has be5 put up "s "t1 be=e proce$+ to "w let him ask que/ions z to :at k9d ( defect !re is1 & :5 & :]e x ev9ces itself4 ,if all ! bells h brok5 d[n1 & w n r+1 ei!r ! batt]y or ! ma9 g & return wires are at fault4 ,let him proce$ to ! batt]y1 exam9e ! b9d+ screws & connect$ wires = corrosion4 ,if !y are all "r1 let ! batt]ies !mselves be te/$ to see if !y are giv+ ! "r am\nt ( curr5t4 ,?is %\ld be done ) ! quantity coil ( ! detector4 ,%\ld ! batt]y be faulty1 x w be well to r5ew ! z9cs & re*>ge ! batt]y1 if ! por\s cell be /ill 9 good condition2 if n1 new cells %\ld be sub/itut$ = ! old ones4 ,%\ld ! batt]y be all "r1 & /ill none ( ! bells r+1 a break or bad contact1 or %ort circuit 9 ! ma9 wires ne> ! batt]y may be ! cause ( ! mis*ief4 ,if "s bell r+s cont9u\sly1 !re mu/ be a %ort circuit 9 ! pu% or pu%es some:]e2 ! upp] spr+ ( "o ( ! pu%es may h got b5t1 or h o!rwise caught 9 ! l[] spr+4 ,pulls are v subject to ?is defect4 ,by viol5t manipulations on ! "p ( mis*iev\s but*] or bak] boys1 ! return spr+ may be brok51 or s f> weak5$ z n to return ! pull into ! (f position4 ,if1 ! batt]ies be+ 9 good ord]1 any bell r+s feebly1 !re is ei!r leakage along its l9e1 or else bad contact 9 ! pu% or 9 ! connections ( ! wires to & f ! pu%4 ,!re %\ld be plat9um contacts at ! ends ( ! pu% spr+s2 if !re are n1 ! spr+s may h work$ dirty at ! po9ts ( contact1 h5ce ! poor curr5t & poor r++4 ,x is seldom t ! bells !mselves1 unless1 inde$1 ( ! l[e/ quality1 give any s]i\s tr\ble4 ,/ill ! set screw may h %ak5 loose 7:i* mu/ !n be adju/$ & tight5$ up71 or ! plat9um speck has got sold] on its face & !re=e got oxidis$4 ,?is may be scrap$ c>efully ) a p5knife until bright4 ,or1 purposely or inadv]t5tly1 no plat9um is on ! speck at all1 only ! sold]4 ,a piece ( plat9um foil %\ld be sold]$ on ! spot1 if ?is is s4 ,or aga9 7& ?is only 9 v bad bells71 ! electro-magnets be+ ( h>d iron1 may h reta9$ a c]ta9 am\nt ( p]man5t magnetism1 & pull ! armature into p]man5t contact ) itself4 ,?is c be rem$i$ by /ick+ a ?9 piece ( pap] 7/amp pap] w d7 ov] ! poles ( ! magnet1 betwe5 !m & ! armature4 ,9 no case %\ld ! fitt] cut or draw up out ( tubes1 etc41 any wire or wires1 )\t hav+ fir/ asc]ta9$ t ! fault is 9 t wire2 =1 h[ev] c>efully jo9ts are made1 x is r>e t ! jo9t$ places are s ?or\ghly insulat$ z !y 7 be=e ! cutt+ & subsequ5t jo9+ 7 und]tak54 ,to avoid z mu* z possible cutt+ uselessly1 let e b9d+ screw be exam9$ & tight5$ up1 & e l5g? ( wire1 :i* x is possible to get at1 be te/$ = cont9uity be=e any sla%+ at ! wires1 or furi\s onslaughts on ! indicator be consummat$4 ,9 conclusion1 ,i beg to record my ?anks = ! v g5]\s assi/ance :i* ,i h receiv$ 9 ! compilation ( ! =ego+ pages f ! electrical firms ( ,messrs4 ,blakey ,emmot1 ,b9swang]1 ,g5t1 ,judson1 ,j5s51 & ,?orpe4 ,,add5dum4 ,,! ,,gassn] ,,batt]y4 ,s9ce ! compilation ( ! =ego+ pages1 a dry batt]y1 kn[n by ! above "n1 has f\nd great fav\r ) electric-bell fitt]s4 ,its peculi>ity consi/s 9 ! z9c elem5t =m+ ! outside cell4 ,9 ?is is plac$ ! c>bon1 :i* is sep>at$ f ! z9c by a ?ick pa/e or jelly made ( gypsum & oxide ( z9c4 ,! cell c be plac$ 9 any position1 works z well on its side z upright1 is n subject to creep+1 has an ,e4,m4,f4 ( ab\t #a4e volt1 ) an int]nal resi/ance ( only #j4be ohm 9 ! r\nd =m1 & #j4f 9 ! flat =m4 ,! ,gassn] dry batt]y pol>izes mu* less quickly ?an ! ord9>y ,leclan*'e4 ,! only defects at pres5t noticeable1 are ! flimsy connections1 & ! fact t ! out] cases be+ metal mu/ be c>efully gu>d$ f t\*+ "o ano!r4 ,?is c be effect$ by enclos+ 9 a p>tition$ wood5 box4 ,,index4 ,a4 ,acid1 ,*romic1 #cc1 #df ---- ,hydrobromic1 #bj ---- ,hydro*loric1 #bj ---- ,hydriodic1 #bj ---- ,nitric1 #bj ---- ,sulphuric1 #bj ,action 9 ,bi*romate1 #dg ---- ,dott+1 #aaf ---- ( electric bell1 #ha ---- ,leclan*'e1 #ce ---- ,relay1 #acd ---- ,rubb+1 #aaf ---- ( z9c on acids1 #ba ,agglom]ate block1 #ch ---- ,cell1 #ch ---- ,compo1 #ch ,al>ms1 ,burgl>1 #aac ---- ,fire1 #abc ---- ,fro/1 #aba ---- ,!rmomet]1 #abb ---- ,?ief1 #aac ---- ,wat*1 #abd ,amb]1 #a ,ampe're1 #ee ,ampe're's law1 #aa ,anneal+ iron1 #ac ,arrangem5t ( bells = lifts1 #aga ---- ,%ips1 #agj ,attraction1 #c ,b4 ,batt]ies1 #ah ,batt]y agglom]ate1 #ci ,batt]y1 ,bi*romate1 #dh ---- ,buns51 #cc ---- ,*romic acid1 #df ---- ,daniell's1 #bi ---- ,gassn] 7add5dum71 #ahf ---- ,g5t's1 #dd ---- ,gravity1 #ca ---- ,modifi$1 #abj ---- ,gr5et1 #df ---- ,grove1 #cc ---- ,judson's1 #da ---- ,leclan*'e1 #cc ---- ,rev]s$1 #df ---- ,m9otto1 #ca ---- ,smee's1 #bg ---- ,walk]'s1 #bg ,bell action1 case =1 #hh ,blocks1 wood51 #aej ,bobb9s1 electric bell1 #fg ,box = batt]ies1 #dc ,bru%es1 dynamo1 #ag ,c4 ,cable1 _m /r&$1 #agd ,case = bell action1 #hh ,cells 9 p>allel1 #eg ---- s]ies1 #ec ,*>g+ fluid1 recipes1 #dh ---- ,full]1 #di ,circuits1 clos$1 #eb1 #aah ---- ,( bells complete 9 h\se1 #afh ---- ,= signall+1 #afg ---- ,9 bo? directions1 #afh ,circuits ( bells ) ,morse key1 #afe ,9 p>allel1 #afa ,s]ies1 #afb ,) relay1 #afd ,s+le bell & wire1 #aei ,e>?1 #afj ,two pu%es1 #afa ,pu% & pull1 #afa ,op51 #eb ,clos$ circuit sy/em1 #aah ,code = signall+1 #acj ,coil spr+1 #ajh ,conductors1 #c ,connect+ up1 #add1 #aei ,contacts1 burgl> al>m1 #aac ,door1 #aaf ,draw]1 #aba ,floor1 #aac ,= clos$ circuits1 #aba ,mack5zie's humm+1 #aac ,%op door1 #aaf ,till1 #aba ,wat* al>m1 #abd ,w9d[ sa%1 #aaf ,corrugat$ c>bons1 #da ,creep+ 9 cells1 #dc ,to rem$y1 #dd ,call['s atta*m5t1 #ii ,curr5t1 #ed ,to r+ bell1 #ade ,d4 ,daniell's cell1 #bi ,action 91 #bi ,deflection ( ne$le1 #i1 #aa ,detector or galvanomet]1 to make1 #agh ,det5t lev]1 #id ,door contact1 #aaf ,dott+ action1 #aaf ,draw+ out plans1 #afi ,dynamo1 #ae ,armature1 #af ,bru%es1 #ag ,commutator1 #ag ,dynamo1 ,cumulative effects1 #ag ,field magnets1 #af ,e4 ,e>?1 #eb ,plate1 #ec ,return1 #aec ,electric bell1 action (1 #ha ,armature1 #gd ,base1 #fa ,bobb9s1 #fg ,contact screw1 #ge ,cont9u\s1 #ib ,circul> bell1 #ajf ,gong1 #gg ,h[ to make1 #fj ,9 lifts1 #aga ,%ips1 #agj ,j5s5's1 #aja ,jo9+ ,e4 ,m4 wire1 #gc ,magnets1 #fc ,magneto1 #agd ,m9+1 #ajf ,p>aff9+1 #fi ,plat9um tip1 #gf ,putt+ toge!r1 #gh ,s+le /roke1 #ia ,spr+1 #gd ,?orpe's1 #ajj ,trembl+1 #ha1 #ij ,w9d+ wire on1 #ga ,wire =1 #fi ,trumpet1 #ajg ,electricity1 s\rces (1 #b ,electrodes1 #bf ,electro-motive =ce1 #ea ,electron1 #a ,e4,m4,f41 #ea ,excitation1 #f ,f4 ,faults to detect1 #ahb ,fire al>ms1 #abc ,floor contacts1 #aac ,fro/ al>ms1 #aba ,full] *>g+1 #di ,g4 ,galvanomet]1 #agf ,gas evolv$1 #ah ,gassn] batt]y 7add5dum71 #ahf ,g5]ator 7magneto71 #agd ,g5t's batt]y1 #dd ,glue1 ,pr\t's ela/ic1 #adh ,graphite1 #bg ,gravity batt]y1 #ca ,daniell batt]y1 #ca ,modifi$1 #abj ,gr5et batt]y1 #df ,grove batt]y1 #cc ,gutta-p]*a1 #adh ,i4 ,indicator1 #ace ,automatic1 #ach ,drop1 #acf ,electric replacem5t1 #acf ,g5t's1 #adj ,tripol>1 #adc ,me*anical replacem5t1 #acf ,mode ( c\pl+ up1 #adb ,p5dulum1 #aci ,pol>is$1 #aci ,self replac+1 #acf ,semaphore1 #acf ,inductor1 #agd ,insulation1 #fh ,insulators1 #d ,int]nal resi/ance1 #ef ,int]ior ( pu%1 #aea ,iron1 importance ( s(t1 #fe ,yoke1 #ff ,j4 ,j5s5's bell1 #aja ,jo9+ wires to pu%1 #aea ,judson's cell1 #da ,k4 ,key1 ,morse1 #abi ,l4 ,leakage1 #eb ,leclan*'e cell1 #cc rev]s$1 #df ,legge's contact1 #aae ,lev] swit*es1 #abh ,lifts1 bells =1 #aga ,localis+ faults1 #add1 #age ,lodge bell1 #afi ,m4 ,magnetic field1 #ad ,magneto bells1 #age ,electric ma*9es1 #ad1 #ae ,magnets1 #ac ,magnets produc+ electricity1 #ad ,magnetisation ( iron1 #ab ,/eel1 #ac ,manganese oxide1 #cc ,m9otto cell1 #ca ,modifi$ gravity batt]y1 #abj ,morse key1 #abi ,musical in/rum5t1 novel1 #ajh ,n4 ,negative electricity1 #g ,non-conductors1 #c ,novel musical in/rum5t1 #ajh ,o4 ,ohm1 #ee ,ohm's law1 #ee ,op5 circuit1 #eb ,ov]head l9es1 #aeb ,p4 ,p>aff91 #fi1 #agj ,p]*a1 gutta1 #adh ,plans1 draw+ out1 #afi ,plat9um1 rivet+1 #gf ,plat9um1 use (1 #gf ,plug swit*es1 #abh ,pol>isation1 #bf ,positive electricity1 #g ,proportions ( bell p>ts1 table (1 #hi ,pressels1 #aaa ,pr\t's ela/ic glue1 #adh ,pulls1 #aaa ,pu%1 #ib1 #aea1 #aji ,int]ior (1 #aea ,jo9+ wires to1 #aea ,r4 ,relay1 #if1 #acc ,action (1 #acd ,repulsion1 #c ,res9\s electricity1 #g ,resi/ance ( wire1 table (1 #adf ,return curr5t1 #aec ,rivet+ plat9um1 #gf ,rubb+ action1 #aaf ,s4 ,%ips1 bells =1 #agj ,%op door contact1 #aaf ,signall+ by bells1 #acj ,code1 #acj ,silv] plat9is$1 #bg ,s+le cell1 #i ,sizes ( ,leclan*'e's1 #db ,smee's cell1 #bg ,spr+ coil1 #ajh ,/&>d size ( wires1 #adf ,swit*es1 lev]1 #abh ,plug1 #abh ,t4 ,table ( batt]ies1 ,e4,m4,f4 & ,r41 #eh ,conductors & insulators1 #d1 #fh ,metals 9 acid1 #h ,table ( ,proportions ( bell p>ts1 #hi ,wire resi/ance1 etc41 #adf ,te/+ new "w1 #ahb ,old1 #ahc ,!rmomet] al>ms1 #abb ,?orpe's ,ball1 #ajj ,u4 ,use ( plat9um1 #gf ,v4 ,vitre\s electricity1 #g ,volt1 #ec ,w4 ,walk]'s cell1 #bg ,wat*man's clock1 #abd ,wat] level indicator1 #abg ,wa%]1 insulat+1 #gg ,w9d[ sa% contact1 #aaf ,wip+ contact1 #ajb ,wire cov]+1 #adg ,9 iron pipes1 #aeb ,9 wood5 boxes1 #aeb ,iron1 #aeb ,jo9+1 #adh ,to pu%1 #aea ,lay+ 9 tubes1 #adi ,lead+1 #adg1 #aej ,ov]head1 #aeb ,resi/ance1 table (1 #adf ,return1 #adg1 #aej ,sold]+ iron1 #adh ,t9n$1 #adg ,und]gr\nd1 #aeb ,wir+1 g5]al in/ructions1 #aee ,up1 #add ,z4 ,z9c1 amalgamat$1 #bb ,black+1 #de ,consumption1 #ba ,comm]cial1 #ai ,pure1 #ai ,,william ,,rid] ,,& ,,son1 ,,pr9t]s1 ,,london4 99 99 99 99 99 ,small cr[n #hvo1 clo?4 ,) _m ,illu/rations4 ,,:ittak]',s ,,libr>y ,,( ,,arts1 ,,sci5ces1 ,,manufactures ,,& ,,indu/ries4 ,,managem5t ,,( ,,accumulators ,,& ,,private ,,electric ,,light ,,in/allations4 ,a ,practical ,h&book by ,sir ,,david ,,salomons1 ,b>t41 ,m4 ,a4 #d? ,edition1 ,revis$ & ,enl>g$1 ) #cb ,illu/rations4 ,clo? #cs4 ,to say t ?is book is ! be/ ( its k9d w\ld be a poor complim5t1 z x is practically ! only "w on accumulators t has be5 writt54--,electrical ,review4 ,,electrical ,,in/rum5t-,,mak+ ,,= ,,amateurs4 ,a ,practical ,h&book4 ,by ,s4 ,r4 ,,bottone1 ,au?or ( ,! ,dynamo1 c4 ,) #fj ,illu/rations4 ,second ,edition4 ,clo? #cs4 ,,electric ,,bells4 ,by ,s4 ,r4 ,,bottone4 ,) num]\s ,illu/rations4 ,,9 ,,prep>ation4 ,,! ,,protection ,,( ,,build+s ,,f ,,lightn+4 ,a ,treatise on ! ,!ory ( ,lightn+ ,conductors f a ,mod]n ,po9t ( ,view4 ,be+ ! sub/ance ( two lectures deliv]$ be=e ! ,society ( ,arts 9 ,m>*1 #ahhh4 ,by ,,oliv] ,j4 ,,lodge1 ,,ll4,d41 ,d4,sc1 ,f4,r4,s41 ,pr(essor ( ,physics 9 ,univ]sity ,college1 ,liv]pool4 ,publi%$ ) v>i\s amplifications & additions1 ) ! approval ( ! ,society ( ,arts4 ,,electrical ,,influ5ce ,,ma*9es3 ,conta9+ a full acc\nt ( _! hi/orical developm5t1 _! mod]n ,=ms1 & _! ,practical ,con/ruction4 ,by ,j4 ,,gray1 ,b4,sc4 ,,electrical ,,eng9e]+ ,,9 ,,our ,,work%ops4 ,a ,practical ,h&book4 ,by ,,sydney ,f4 ,,walk]4 ,ready ,%ortly 99 99 99 99 99 ,transcrib]'s ,note ,page #ab3 *ang$ guage to gauge 7444 cotton-cov]$ copp] wire1 say ,no4 #bj gauge 4447 ,page #ce3 *ang$ *ange to *>ge 7444 los+ at ! same "t its electrical *>ge 4447 ,page #ee3 *ang$ guage to gauge 7444 #a foot ( ,no4 #da gauge pure copp] wire 4447 ,page #fd3 *ang$ exaet to exact 7444 ( ! exact diamet] ( ! turn$ ends ( ! cores 4447 ,page #gc3 mov$ comma ,rivett+1 is to ,rivett+ is1 7,rivett+1 is p]haps1 ! be/ mode 4447 ,page #ha3 add$ hyph5 7444 along ! %ort l5g? ( wire to ! "r-h& b9d+-screw 4447 ,page #hc3 *ang$ head to heads 7444 ! possible defects ( electric bells may be class$ "u f\r heads3 4447 ,page #ib3 *ang$ its to x 7444 until x re/s aga9/ ! /op or /uds47 ,page #ajb3 *ang$ contract-break] to contact-break] 7,:5 ! contact-break] is us$1 4447 ,page #ajc3 *ang$ in/ead to ,in/ead 7,in/ead ( ! armature & clapp] 4447 ,page #acb3 9 ! ,morse code = ,,br+ ,,!1 ! code = ,h has be5 correct$ f two dots to f\r dots4 ,page #acf3 *ang$ eletro-magnet to electro-magnet 7444 if ! electro-magnet 7 en]gis$ 4447 ,page #acg3 *ang$ idicator to indicator 7s9ce ! indicator falls =w>ds7 ,page #adf3 *ang$ arrangm5t to arrangem5t 7! size & arrangem5t ( ! batt]ies & wires7 ,page #adf3 add$ comma nails1 7444 *ance contact ) nails1 /aples1 metal pipes or o!r wires 4447 ,page #agi3 *ang$ c>bo>d to c>dbo>d 7444 = our purpose we w *oose c>dbo>d47 ,page #agi3 *ang$ ,tan/ickor to ,t3and/ickor 7444 d\ble x to ! =m ( a ,t3and/ickor mat*-box1 4447 ,page #ahe3 suspect$ typo 7un*ang$7 ,emmot %\ld p]haps be ,emmott 7444 ! electrical firms ( ,messrs4 ,blakey ,emmot1 4447 ,page #ahf3 *ang$ ,leclan*e' to ,leclan*'e 7444 pol>izes mu* less quickly ?an ! ord9>y ,leclan*'e47 ,page #ahg3 *ang$ two in/ances ( ,amp'ere to ,ampe're 9 ! index 7,ampe're1 #ee _/ ,ampe're's law1 #aa7