,transcrib]'s ,notes3 ,text pr9t$ 9 italics1 bold face & small capitals 9 ! orig9al "w h be5 transcrib$ betwe5 und]scores1 equal signs & ,,all ,,capitals1 respectively4 ,dep5d+ on ! h>d- & s(tw>e us$ to read ?is text & _! sett+s1 n all *>act]s may display z int5d$4 ,m ,transcrib]'s ,notes may be f\nd at ! end ( ?is text4 ,books by ,hor/mann ,t\sley ,motion ,picture ,op]ation1 ,/age ,electrics & ,illusions4 #b4jj 7,ready ,july #a1 #aiad47 ,alt]nat+ ,curr5t ,!ory1 ,practice & ,diagrams4 #b4jj ,mod]n ,electric ,illum9ation4 #b4jj ,practical ,armature & ,magnet ,w9d+4 #a4ej ,mod]n ,electrical ,con/ruction4 #a4ej ,electrical ,wir+ & ,con/ruction ,tables4 #a4ej ,dynamo ,t5d+ = ,eng9e]s4 #a4ej ,mod]n ,wir+ ,diagrams & ,descriptions4 #a4ej ,electricians' ,op]at+ & ,te/+ ,manual4 #a4ej ,motion ,picture ,op]ation ,,/age ,,electrics ,,& ,,illusions ,a ,practical ,h&-book & ,guide = ,!at] ,electricians1 ,motion ,picture ,op]ators & ,manag]s ( ,!at]s & ,productions ,by ,h5ry ,c4 ,hor/mann & ,victor ,h4 ,t\sley ,au?ors ( 8,alt]nat+ ,curr5t10 8,mod]n ,wir+ ,diagrams10 8,mod]n ,electrical ,con/ruction10 8,electrical ,wir+ & ,con/ruction ,tables10 8,practical ,armature & ,magnet ,w9d+10 8,electricians' ,op]at+ & ,te/+ ,manual10 8,mod]n ,illum9ation40 ,,illu/rat$ ,illu/ration ,*icago ,,fr$]ick ,j4 ,,drake ,,co4 ,publi%]s ,copyright #aiad1 by ,,h5ry ,c4 ,,hor/mann & ,,victor ,h4 ,,t\sley ,,preface ,9 ?is volume ! au?ors h attempt$ to lay be=e ! ,motion-,picture ,op]ators & ,!atrical ,employes g5]ally1 a ref]5ce & h&book mak+ a specialty ( electrical requirem5ts ab\t !at]s4 ,a work+ k ( electricity 9 g5]al is assum$1 & !re=e elem5t>y ideas h be5 treat$ sp>+ly4 ,a specialty1 h[ev]1 has be5 made ( all matt]s peculi> to !at]s1 & x is ?\ght t !at] electricians w f9d 9 ?is volume ev]y?+ t !y ne$ :e!r !y be op]at+ motion-picture ma*9es or swit*bo>ds 9 fir/-class h\ses4 ,! two special *apt]s 8,portable ,/age ,equipm5t0 & 8,!at] ,wir+0 h be5 arrang$ s t !y are p>ticul>ly valuable = ref]5ce4 ,!y %\ld be consult$ be=e und]tak+ any electrical con/ruction "w1 ei!r = ! /age or = ! auditorium4 ,^! *apt]s embody all ( ! practical k t has come to ! notice ( ! au?ors 9 _m ye>s ( actual exp]i5ce ) !atrical con/ruction4 ,! aim ( ?is volume has be5 to pres5t 9 a simple & practical way ! ess5tial pr9ciples ( ,motion-,picture ,"w4 ,,! ,,au?ors4 ,table ( ,cont5ts ,,page ,,*apt] ,i ,! ,electrical ,circuit & ,electrical ,haz>ds #i ,,*apt] ,,ii ,! ,arc ,lamp #ai ,,*apt] ,,iii ,projection #ca ,,*apt] ,,iv ,motion ,pictures #ee ,,*apt] ,v ,! ,motion-,picture ,ma*9e #fb ,,*apt] ,,vi ,! ,film #hi ,,*apt] ,,vii ,g5]al ,h9ts on ,in/allation1 ,op]ation & ,c>e ( ,ma*9es #if ,,*apt] ,,viii ,light #aac ,,*apt] ,,ix ,pr9ciples ( ,vision #abb ,,*apt] ,x ,reflection #abf ,,*apt] ,,xi ,refraction #acg ,,*apt] ,,xii ,optical ,in/rum5ts #adg ,,*apt] ,,xiii ,optical ,illusions #aee ,,*apt] ,,xiv ,!at] ,build+s #afc ,,*apt] ,,xv ,op]at+ ,room ,equipm5t #agf ,,*apt] ,,xvi ,curr5t ,control = ,arc ,lamps #aij ,,*apt] ,,xvii ,managem5t ( ,g5]ators & ,motors #bac ,,*apt] ,,xviii ,!at] ,wir+ #bah ,,*apt] ,,xix ,portable ,/age ,equipm5t #caa ,,*apt] ,,xx ,useful ,facts & ,=mulas #cec ,,*apt] ,,xxi ,gloss>y ( ,electrical1 ,me*anical & ,optical ,words1 ,t]ms & ,phrases #ceh ,index #che ,,motion ,,picture ,,op]ation ,,/age ,,electrics ,,& ,,illusions ,,*apt] ,i4 ,,! ,,electrical ,,circuit ,,& ,,electrical ,,haz>ds4 ,two & ,?ree-,wire ,sy/ems4--,if ! !at] electrician w take ! tr\ble to trace ! circuits 9 ! build+ to _! supply1 he w f9d !m ent]+ ! build+ ei!r z two-wire or ?ree-wire circuits4 ,illu/ration3 ,,figure #a4 ,a two-wire circuit is diagrammatically %[n 9 ,figure #a4 ,! circuit1 com+ f #a1 ent]s ! build+1 passes ?r\gh ! fuses #b1 & ?r\gh swit* #c to ! lights4 ,a two-wire sy/em w ord9>ily be f\nd op]at+ at #aaj volts1 ! curr5t v>y+ accord+ to ! numb] ( lights turn$ on4 ,9 ! draw+1 = in/ance1 only "o light is %[n ) ! swit* clos$1 ! o!r ?ree swit*es be+ op54 ,! curr5t 9 ! circuit is equal to t :i* passes ?r\gh ! s+le lamp4 ,if ano!r swit* be clos$1 ano!r light w burn & ! curr5t w be increas$1 s t ! m lights be turn$ on1 ! great] w be ! curr5t4 ,illu/ration3 ,,figure #b4 ,! ?ree-wire sy/em1 ,figure #b1 is almo/ univ]sally us$ :]e ! supply is f ! outside & :]e any consid]able numb] ( lights are connect$4 ,! *ief advantage ( ! ?ree-wire sy/em lies 9 its economy ( copp]4 ,! middle or neutral wire ord9>ily does n c>ry curr5t1 b x is a necessity :5ev] ! numb] ( lights burn+ on ! two sides ( ! sy/em are n equal4 ,) ! neutral wire omitt$1 we h a /raight two-wire sy/em us+ d\ble ! voltage ( ! ord9>y two-wire sy/em & always op]at+ two #aaj-volt lamps 9 s]ies4 ,two lamps w\ld always h to be turn$ on at ! same "t & if "o ( !m %\ld burn out1 ! o!r w\ld be ext+ui%$ also4 ,a sy/em us+ d\ble voltage requires only half ! curr5t & consequ5tly b half ! copp]4 ,9 ord] to obviate ! necessity ( always us+ two lamps toge!r & at ! same "t economiz+ 9 copp]1 ! neutral wire is provid$4 ,z long z ! same numb] ( lamps are burn+ on ea* side ( ! neutral wire1 ! same curr5t always passes ?r\gh two lamps 9 s]ies & !re is no curr5t 9 ! neutral4 ,%\ld1 h[ev]1 ! gr\p on "o side be turn$ out1 ! o!r w\ld /ill cont9ue to burn2 b ! pa? ( ! curr5t to ! dynamo1 or bank ( trans=m]s1 w\ld be ?r\gh ! neutral wire4 ,! sy/em is ?us se5 to possess all ! advantages ( ! ord9>y two-wire sy/em s9ce ea* lamp c be op]at$ by itself & at ! l[ voltage1 :ile ! actual supply voltage = ! :ole sy/em is d\ble t :i* is actually us$ at any lamp4 ,we h ?us two voltages at our comm&2 #aaj & #bbj be+ ! voltages 9 common use4 ,electrical ,haz>ds4--,s9ce ?is "w is n int5d$ = m]e beg9n]s1 we %all n ent] into elem5t>y consid]ations1 b %all take up ! matt] ( fire & life haz>d1 bo? ( :i* are important items to :i* att5tion _c be too (t5 call$4 ,! electrical curr5t may cause fire by ov]heat+ ! wires4 ,?is ov]heat+ may be due to ! willful ov]load+ ( circuits2 & to prev5t ?is1 no wire %\ld ev] be us$ to c>ry m curr5t ?an is all[$ by ! table ( c>ry+ capacities giv5 on page #bch4 ,! ov]heat+ may also be due to an unkn[n load :i* is caus$ by a 8gr\nd0 or a p>tial %ort circuit4 8,gr\nd0 is ! te*nical t]m us$ to designate ! connection ( a wire to any sub/ance ov] :i* electricity may be c>ri$ to ! wire ( opposite pol>ity4 ,a gr\nd may be caus$ by a b>e wire com+ 9 contact ) ! iron framework ( a build+1 wet wood1 or moi/ sub/ances ( any k9d4 ,"o su* gr\nd on a circuit c d no h>m2 b1 if "o gr\nd exi/s1 9 ! c\rse ( "t ano!r "o may come on &1 :5 ! second "o appe>s1 if x is on ! side ( ! circuit opposite to ! fir/1 !re w be tr\ble at once4 ,if ! two gr\nds are bo? 8good0--t is1 if !y are ( l[ resi/ance--we %all h a %ort circuit & probably bl[ a fuse2 b if !y are n 8good10 we may h b a small curr5t :i* may cont9ue unnotic$ = mon?s4 ,su* a curr5t may eat away ! copp] ( ! positive pole & 9 "t cause ! wire to break1 creat+ an electric arc & p]haps caus+ a fire4 ,x may also cause wet wood ?r\gh :i* x fl[s to become *>r$ & f9ally ignit$4 ,! gr\nd is ! bane ( ! electrical work]4 ,if a sy/em c be kept free ( gr\nds1 ! *ances ( tr\ble are va/ly r$uc$4 ,! cause ( mo/ gr\nds is moi/ure4 ,ne>ly all sub/ances except metals are fairly good insulators if dry2 & ne>ly all ( !m are fairly good conductors if suffici5tly wet4 ,ano!r v prolific s\rce ( fires is ! electrical sp>k1 l>ge & small4 ,! sp>k1 due to ! break+ ( an inc&esc5t lamp1 (t5 causes fires :5 x comes 9 contact ) inflammable mat]ial or gases4 ,! ord9>y lamp cord also causes _m fires because x is easily damag$ & liable to %ort circuits :i* (t5 result 9 arc+4 ,%ort circuit+ two wires or break+ a wire c>ry+ curr5t may easily ignite inflammable mat]ial 9 ! vic9ity4 ,! be/ way to r$uce ! fire haz>d to a m9imum1 is to in/all all electrical "w c>efully accord+ to ! rules laid d[n 9 ! 8,national ,electrical ,code04 ,! life haz>d is "o :i* conc]ns ! op]ator p]sonally & is especially great to ^? travel+ ) %[s4 ,travel+ m5 are (t5 oblig$ to get along ) all sorts ( make %ifts1 especially 9 ! small] t[ns :]e "o-night /&s are ! rule4 ,"h x is (t5 necess>y to connect to trolley circuits or p[] l9es ( diff]5t voltages1 frequ5cies1 etc4 ,a p]son may suff] injury directly f a curr5t ( electricity by mak+ himself "p ( ! circuit4 ,if ! sy/em on :i* he is work+ is alive & gr\nd$1 he may easily cause injury to himself by t\*+ a live wire ) 8 h&s :ile /&+ ^u any?+ t is gr\nd$4 ,by s do+ he completes a pa? = ! curr5t ?r\gh 8 body4 ,he may also become "p ( a circuit by hold+ a wire ) bo? h&s :ile someone is cutt+ x betwe5 8 two h&s4 ,z long z a wire s held is intact1 no %ock c be receiv$ except to gr\nd1 b :5 ! wire is cut or breaks1 a v high voltage may be produc$ = an in/ant :i* w cause a curr5t ?r\gh ! body ( ! man hold+ ! wire4 ,! extra high voltage is produc$ only if ! wire is c>ry+ curr5t at ! "t x is be+ cut4 ,"u ^! circum/ances !re w (t5 be a /rong fla%1 due to ! mom5t>y increase 9 voltage1 produc$ by ! break+ ( ! circuit1 :i* may be excessive1 especially if !re is consid]able inductance 9 ! circuit4 ,! mo/ frequ5t cause ( injury is due to mak+ contact ) ! two opposite pol>ities ( a sy/em4 ,z a rule circuits1 ) :i* op]ators ord9>ily h to "w1 are l[ voltage1 i4e41 n ov] #bbj volts4 ,b _m dea?s h be5 caus$ by ?is voltage1 sometimes directly & at o!r times indirectly z1 = in/ance1 by caus+ a fall4 ,p ^: he>ts are 9 any way defective %\ld be c>eful ab\t expos+ !mselves to %ocks ev5 at #aaj volts4 ,x is true t _m wirem5 are 9 ! habit ( te/+ #bbj-volt circuits by all[+ ! curr5t to pass ?r\gh _! bodies1 b x w be notic$ t !y are v c>eful n to make a good contact4 ,! curr5t :i* passes ?r\gh ! body1 :5 "o t\*es two wires ( opposite pol>ity v lightly ) ! f+] tips1 is b a fraction ( :at "o w\ld receive if he 7 unwitt+ly to grab two wires ( opposite pol>ities ) ! h&s1 especially if ! h&s 7 moi/4 ,num]\s cases are on record ( p]sons hav+ be5 kill$ by #aaj volts "u favorable circum/ances2 z1 = in/ance1 :ile 9 ! ba? receiv+ a %ock f a s-call$ vibrator4 ,! body p>tly imm]s$ 9 wat] & p]haps a foot re/+ aga9/ a wat] pipe =ms a conductor ( v l[ resi/ance1 & a comp>atively /rong curr5t may pass ?r\gh ! body4 ,! mo/ important precautions aga9/ injury :ile work+ on live circuits are3 7#a7 ,insulate y\rself f ! gr\nd4 7#b7 ,h&le only "o side ( a l9e at a "t4 7#c7 ,if possible1 "w ) only "o h& at a "t 9 contact ) ! wires4 7#d7 ,use rubb] gloves1 or rubb] boots :]e necess>y1 b be> 9 m9d t !y are ( little value unless kept dry4 ,moi/ure w all[ "s curr5t to pass ov] ! surface ( any sub/ance no matt] h[ good an insulator x may o!rwise be4 7#e7 ,always place y\rself s t a slight %ock :i* might cause y to lose y\r balance w n give y a bad fall4 7#f7 ,rememb] t if once y make good contact ) an alt]nat+-curr5t circuit1 y _c let g4 7#g7 ,fix firmly 9 y\r m9d ! directions = resuscitation f electric %ock1 on pages #ae-ah4 ,:5 en]gy is obta9$ ?r\gh trans=m]s1 !re is ano!r dang] to be add$ to ! above1 viz41 ! possibility ( ! break+ d[n ( ! insulation betwe5 prim>y & second>y wires ( ! trans=m]4 ,if ?is happ5s1 we h sudd5ly & )\t w>n+1 in/ead ( ! #aaj or #bbj volts suppos$ to exi/ betwe5 ! wires =m+ ! circuit1 #b1jjj or #c1jjj volts4 ,su* accid5ts are especially likely dur+ ?und] /orms :5 lightn+ (t5 breaks d[n trans=m]s4 ,9 ord] to r$uce ?is dang] to a m9imum1 ! second>ies ( trans=m]s are gr\nd$4 ,x w be well = ! electrician to assure himself t ! second>ies ( ! trans=m]s f :i* he is gett+ 8 supply are gr\nd$4 ,?is c be te/$ by an inc&esc5t lamp4 ,connect ! lamp to gr\nd ) "o wire &1 ) ! o!r1 try ! two sides ( ! circuit4 ,if ! trans=m] second>ies are prop]ly gr\nd$1 ! lamp w burn at full c&le p[] f "o ( ! wires2 ?is w %[ t ! o!r wire is gr\nd$4 ,a p]son work+ on su* a circuit is ( c\rse m likely to receive a l[ voltage %ock ?an if ! second>ies 7 n gr\nd$1 b he is fairly well protect$ aga9/ ! prim>y voltage or lightn+4 ,,resuscitation ,,f ,,electric ,,%ock4 ,rules recomm5d$ by commission on resuscitation f electric %ock1 repres5t+ ,! ,am]ican ,m$ical ,association1 ,! ,national ,electric ,light ,association1 ,! ,am]ican ,in/itute ( ,electrical ,eng9e]s3 ,dr4 ,w4 ,b4 ,cannon1 *airman2 pr(essor ( physiology1 ,h>v>d ,univ]sity4 ,dr4 ,y&ell ,h5d]son1 pr(essor ( physiology1 ,yale ,univ]sity2 ,dr4 ,s4 ,j4 ,meltz]1 head ( dep>tm5t ( physiology & ph>macology1 ,rockefell] ,in/itute = ,m$ical ,rese>*2 ,dr4 ,edw4 ,an?ony ,spitzka1 director & pr(essor ( g5]al anatomy1 ,daniel ,baugh ,in/itute ( ,anatomy1 ,jeff]son ,m$ical ,college2 ,dr4 ,george ,w4 ,crile1 pr(essor ( surg]y1 ,we/]n ,res]ve ,univ]sity2 ,w4 ,c4 ,l4 ,egl91 pa/-presid5t ,national ,electric ,light ,association2 ,dr4 ,a4 ,e4 ,k5nelly1 pr(essor ( electrical eng9e]+1 ,h>v>d ,univ]sity2 ,dr4 ,elihu ,?omson1 electrician1 ,g5]al ,electric ,company2 ,w4 ,d4 ,weav]1 secret>y1 editor ,electrical ,_w4 ,issu$ & copyright$ by ,national ,electric ,light ,association4 ,repr9t$ by p]mission4 ,foll[ ^! in/ructions ev5 if victim appe>s dead4 ,i4 ,,imm$iately ,,break ,,! ,,circuit4 ,) a s+le quick motion1 free ! victim f ! curr5t4 ,use any dry non-conductor 7clo?+1 rope1 bo>d7 to move ei!r ! victim or ! wire4 ,bew>e ( us+ metal or any moi/ mat]ial4 ,:ile free+ ! victim f ! live conductor h e ef=t also made to %ut (f ! curr5t quickly4 ,,ii4 ,,in/antly ,,att5d ,,to ,,! ,,victim',s ,,brea?+4 #a4 ,z soon z ! victim is cle> ( ! conductor1 rapidly feel ) y\r f+] 9 8 m\? & ?roat & remove any =eign body 7tobacco1 false tee?1 etc47 ,!n beg9 artificial respiration at once4 ,d n /op to loos5 ! victim's clo?+ n[2 e mom5t ( delay is s]i\s4 ,proce$ z foll[s3 a4 ,lay ! subject on 8 belly1 ) arms ext5d$ z /raight=w>d z possible & ) face to "o side1 s t nose & m\? are free = brea?+1 see ,figure on page #ag4 ,let an assi/ant draw =w>d ! subject's tongue4 ,illu/ration3 ,,inspiration--,,pressure ,,(f4 b4 ,kneel /raddl+ ! subject's ?ighs & fac+ 8 head2 re/ ! palms ( y\r h&s on ! lo9s 7on ! muscles ( ! small ( ! back71 ) f+]s spread ov] ! l[e/ ribs1 z 9 ,figure on page #ag4 c4 ,) arms held /raight1 sw+ =w>d sl[ly s t ! weight ( y\r body is gradually1 b n viol5tly1 br\ght to be> ^u ! subject1 see ,figure on page #ah4 ,?is act %\ld take f two to ?ree seconds4 ,imm$iately sw+ backw>d s z to remove ! pressure1 ?us return+ to ! position %[n 9 ! ,figure on page #ag4 d4 ,repeat delib]ately twelve to fifte5 times a m9ute ! sw++ =w>d & back--a complete respiration 9 f\r or five seconds4 e4 ,z soon z ?is artificial respiration has be5 />t$1 & :ile x is be+ cont9u$1 an assi/ant %\ld loos5 any tight clo?+ ab\t ! subject's neck1 *e/ or wai/4 ,illu/ration3 ,,expiration--,,pressure ,,on4 #b4 ,cont9ue ! artificial respiration 7if necess>y1 at lea/ an h\r71 )\t int]ruption1 until natural brea?+ is re/or$1 or until a physician arrives4 ,if natural brea?+ /ops aft] be+ re/or$1 use artificial respiration aga94 #c4 ,d n give any liquid by m\? until ! subject is fully consci\s4 #d4 ,give ! subject fre% air1 b keep him w>m4 ,,iii4 ,,s5d ,,= ,,ne>e/ ,,doctor ,,z ,,soon ,,z ,,accid5t ,,is ,,discov]$4 ,,*apt] ,,ii4 ,,! ,,arc ,,lamp4 ,g5]al ,discussion ( ! ,electrical ,arc4--,! "n ( ! electrical arc lamp is d]iv$ f ! ar*-l appe>ance ( ! vapors :i* give out ! light :5 ! c>bons are plac$ horizontally4 ,! horizontal arc 0 ! e>lie/ =m1 h5ce ! "n :i* x c>ries to ?is day4 ,! arc prop] is due to ! vapors ( volatiliz$ c>bon or o!r mat]ials =m+ ! electrodes1 :i* may be consum$ by ! passage ( an electrical curr5t f "o electrode to ano!r ?r\gh ! int]v5+ m$ium4 ,9 ord] t an arc may be =m$1 x is necess>y fir/ to br+ ! electrodes toge!r4 ,?is1 if ! circuit is prop]ly arrang$1 />ts ! curr5t & :5 ! circuit is p>tly int]rupt$1 z by sl[ly sep>at+ ! po9ts ( ! electrodes1 ! curr5t passes ?r\gh ! int]v5+ space1 ) ! result t a high degree ( heat 7ab\t #c1ejj c5tigrade7 is produc$4 ,?is results 9 volatiliz+ ! c>bon or any o!r mat]ial ( :i* "o or bo? electrodes may consi/4 ,z long z ! di/ance betwe5 ! electrode po9ts is small1 ! curr5t w be q /rong & a hiss+ or fry+ s\nd w be giv5 out4 ,9 ord] to keep ! curr5t )9 b\nds dur+ ! "t t ! electrodes are toge!r or :ile !y are sep>at$ only a v %ort di/ance1 "s resi/ance1 or reactance 9 ! case ( alt]nat+-curr5t arcs1 is always connect$ 9 s]ies 9 ! circuit4 ,if ?is 7 n done1 !re w\ld be a %ort circuit at ! "t ( />t+ or /rik+ ! arc4 ,! arc =m$ ) v %ort sep>ation ( electrodes is g5]ally spok5 ( z a l[ t5sion arc & requires v h>d c>bons & ab\t #be volts4 ,?is type ( arc is v little us$ = illum9at+ purposes4 ,if ! di/ance betwe5 ! electrodes is increas$ gradually1 ! light becomes v un/eady & flick]s consid]ably until at a c]ta9 po9t x beg9s to improve & give ! long quiet arc4 ,?is condition w occur :51 ) direct curr5t1 ! electrodes are ab\t "o-eigh? ( an in* ap>t4 ,x w !n be f\nd t ! voltage across ! arc is f #de to #ej volts1 :i* is ! be/ voltage to use ) op5 arcs4 ,if ! sep>ation be c>ri$ /ill fur!r1 ! arc w gr[ long] & become flam+ until f9ally x breaks entirely4 ,! resi/ance ( ! arc is closely proportional to ! cross section ( ! electrodes & increases ) ! di/ance ( ! arc gap4 ,x acts1 h[ev]1 v mu* z ?\gh !re 7 a small c\nt] e4 m4 f4 set up )9 x4 ,! color ( ! light giv5 (f v>ies ) ! l5g? ( ! arc some:at1 b dep5ds ma9ly ^u ! mat]ial ( :i* ! electrodes consi/4 ,9 ! s-call$ flam+ arcs1 ! peculi> color is obta9$ by c]ta9 *emicals imb$d$ 9 ! mat]ial compos+ ! electrodes4 ,:5ev] an arc is all[$ to burn d[n until x rea*es ! electrode hold]s1 a gre5i% light is giv5 (f :i* is due to ! volatilization ( ! metal--usually brass--9 ^! hold]s4 ,! light ( a /rong arc is extremely injuri\s to ! eyes & %\ld only be view$ ?r\gh color$ glass4 ,_m v pa9ful exp]i5ces h result$ f p]sons gaz+ ^u arcs ( #bjj or #cjj amp]es1 su* z are us$ sometimes 9 cutt+ away metals ( old build+s1 etc4 ,! mo/ p[]ful arcs kn[n at ! pres5t "t are ^? us$ 9 "s /eel mills = ref9+ /eel4 ,^! use upw>d ( #aj1jjj amp]es4 ,illu/ration3 ,,figure #c4 ,illu/ration3 ,,figure #d4 ,! l5g? ( ! ord9>y arc v>ies f "o ?irty-second ( an in* to "o in*4 ,! light is n ( mu* use & is r un/eady until ! electrodes h assum$ a %ape some:at simil> to t %[n 9 ,figure #c = direct curr5t1 & ,figure #d = alt]nat+ curr5t4 ,) direct-curr5t arcs1 a crat] is =m$ at ! bottom ( ! positive electrode &1 f ?is crat]1 ab\t #hj p] c5t ( ! light is emitt$4 ,:]e ! light is want$ 9 a d[nw>d direction1 ! crat] is always =m$ at ! top & = ?is purpose ! top electrode mu/ be made positive2 t is1 ! electricity mu/ fl[ f ! top electrode into ! l[] "o4 ,9 "s cases1 :]e special illum9ation effects are desir$1 ! bottom electrode is made ! positive ) ! result t mo/ ( ! light is ?r[n upw>d4 ,9 su* cases /rong %ad[s are ?r[n aga9/ ! ceil+ & ! lamp is said to be burn+ 8upside d[n40 ,! positive electrode c always be di/+ui%$ f ! negative 7a7 by ! %ad[s ca/2 7b7 by ! =m ( ! electrodes2 & 7c7 by ! fact t s9ce x is heat$ to a great] degree1 x w1 :5 ! lamp is turn$ (f1 rema9 hot = "s "t aft] ! negative electrode has cool$ (f4 ,9 case ! arc is drawn out v long & op]at$ 9 ?is way = a consid]able "t1 ! crat] w almo/ :olly disappe> & ! electrodes w appe> r\nd$ (f4 ,9 an alt]nat+-curr5t circuit1 ! positive & negative poles rev]se g5]ally ab\t #abj times p] second & bo? electrodes 9 ! alt]nat+-curr5t arc are positive & negative to ! same degree4 ,!y are !re=e v ne>ly alike1 except t ! heat ris+ f ! l[] "o increases slightly ! volatilization ( ! upp]4 ,! positive electrode 9 ! direct-curr5t arc is consum$ approximately twice z fa/ z ! negative electrode4 ,! consumption ( ! two electrodes 9 an alt]nat+-curr5t arc is ab\t equal & a crat] mu* small] ?an ! k9d =m$ 9 a direct-curr5t arc is1 !re=e1 =m$ on ea* electrode1 in/ead ( only on ! positive electrode z 9 ! case ( ! direct-curr5t arc4 ,! g5]al =m ( alt]nat+-curr5t arc c>bons is giv5 9 ,figure #d4 ,! small elevations %[n 9 ! cuts are due to impurities & d n appe> ) fir/-class c>bons4 ,:5 arc lamps are op]at$ on alt]nat+-curr5t circuits1 ! be/ voltage = ! arc is ab\t #bh2 & consequ5tly1 = ! same quantity ( light1 ! curr5t mu/ be increas$ s t ! amp]age ( alt]nat+-curr5t lamps is always mu* great] ?an t ( direct-curr5t lamps4 ,! alt]nat+-curr5t arc is mu* noisi] ?an ! direct-curr5t arc1 b ) v high frequ5cies ?is noise ceases4 ,9 g5]al1 arc lamps d n "w v well on l[ frequ5cies4 ,! "t at :i* ! curr5t is practically z]o is long en\gh to all[ ! vapor betwe5 ! electrode po9ts to cool (f suffici5tly to int]f]e ) successful op]ation4 ,any arc light is affect$ by draughts ( air & c ev5 be bl[n out4 ,if ?is occurs (t51 !re w be rapid fe$+1 a %ort arc1 & great wa/e ( electrode4 ,a magnet held close to an arc c be made to bl[ x out or =ce x to "o side4 ,?is fact is made use ( 9 "s lightn+ arre/]s4 ,g5]ally speak+1 arc lamps are ( two k9ds1 op5 & enclos$4 ,! enclos$ arc op]ates at a mu* high] voltage & is b little us$ ab\t !at]s4 ,! op5 arc is almo/ univ]sally us$ = /age "w & ?is is ab\t ! only place :]e x is /ill consid]$ useful4 ,?is k9d ( arc lamp is1 h[ev]1 v haz>d\s 9 localities :]e inflammable mat]ial ab\nds & = ?is reason x is always enclos$ ) wire me% :5 possible4 ,l5s lamps c be tightly enclos$ s9ce none ( ! light is want$ except t :i* passes ?r\gh ! l5s 9 front4 ,illu/ration3 ,,figure #e4 ,illu/ration3 ,,figure #f4 ,! s-call$ flood lamps are usually provid$ ) wire gauze 9 front ( ! arc1 :i* prev5ts ! escape ( pieces ( ! electrodes & also prev5ts p>ts ( sc5]y1 etc41 f com+ 9 contact ) ! arc4 ,! lamp h\ses %\ld be ( su* dim5sions t1 ) ! highe/ amp]age ! lamp is capable ( us+1 ! out] walls w n become excessively hot4 ,illu/rations ( /&>d l5s & flood lamps1 z made by ! ,*icago ,/age ,light+ ,company1 are %[n 9 ,figures #e & #f4 ,op]ation ( ,arc ,lamps4--,f ! /&po9t ( op]ation1 arc lamps may be divid$ into two classes1 viz43 h&-fe$ & automatic-fe$4 ,! h&-fe$ lamp is g5]ally us$ 9 !at]s & is practically ! only k9d admitt$ on ! /age1 or = /age illum9at+ purposes4 ,only a v few h\ses n[ use arc lamps = g5]al illum9ation4 ,! op]ation ( h&-fe$ lamps#a is ord9>ily q simple & w be fully treat$ "u ! head ( 8,projection01 s t we may n[ consid] only ! automatic lamps4 ,at ! pres5t "t ^! are us$ mo/ly1 if at all1 = ! illum9ation ( ! ext]ior ( ! !at]4 #a ,full diagrams & descriptions are 9 ano!r "w ( ! au?ors'1 entitl$ 8,electricians' ,op]at+ & ,te/+ ,manual10 s t no space ne$ be giv5 to ^! "h1 save 9 a v g5]al way4 ,! op]ator %\ld fir/ famili>ize himself ) ! con/ruction & pr9ciples ^u :i* ! me*anism ( 8 lamp is bas$4 ,= ?is purpose he %\ld remove ! out] jacket1 ?us expos+ ! work+ me*anism2 turn on ! curr5t2 & endeavor to le>n ! significance ( ea* "p4 ,x is ( c\rse necess>y t ! op]ator und]/& ! haz>ds due to manipulat+ live wires & t he %\ld be v c>eful n to make %ort circuits or gr\nds :i* might de/roy p>ts ( ! lamp4 ,automatic-fe$ lamps are usually trimm$ 9 ! foll[+ mann]3 ,br+ ! lamp )9 rea*2 remove ! globe2 take out ! l[] electrode2 let d[n ! upp] electrode rod & ?or\ghly clean x ) crocus clo?4 ,?is upp] electrode rod is ! pr9cipal ?+ t conc]ns ! lamp trimm]2 x mu/ be p]fectly /raight & c>e mu/ be ex]cis$ n to b5d x accid5tally2 x mu/ be clean s t ! clut*es may prop]ly grip x2 x mu/ n be greasy4 ,if x gr[s dirty or greasy1 x w soon become pitt$ f ! curr5t t passes f ! contacts to x4 ,! next op]ation is to remove ! upp] electrode & place x 9 ! l[] electrode hold]4 7,! l5g? ( electrode necess>y %\ld be kn[n4 ,! l[] "o g5]ally burns out fir/--x be+ %ort]--& if ! arc rea*es ! l[] electrode hold]1 w beg9 to consume x2 if ! l[] c>bon is too long1 ! arc is liable to rea* ! upp] electrode hold] & de/roy x47 ,! upp] electrode may !n be plac$ 9 position & align$ ) ! l[]4 ,to d ?is x is be/ to turn x ab\t & try x until x aligns 9 all positions4 ,! two electrodes %\ld =m a /raight l9e1 up & d[n1 no matt] :i* way ! upp] is turn$4 ,9 "s =ms ( enclos$ lamps1 ! clut* grips ! electrode direct4 ,9 su* a case all ( ! upp] electrode mu/ be c>efully exam9$ to see t x is /raight & free f burs1 & t x c pass freely into ! op5+ at ! top ( ! inn] globe4 ,! successful op]ation ( enclos$ arcs dep5ds ^u ! conf9em5t ( ! gas 9 ! inn] globe4 ,?is globe mu/1 !re=e1 be kept z tight z possible )\t int]f]+ ) ! op]ation ( ! electrodes :i* pass ?r\gh x4 ,) enclos$ arcs1 ! c>e ( ! inn] globe is ( great importance1 because impurities are ca/ (f :i* soon coat ! inn] globe & absorb mu* ( ! light4 ,! c>e ( ! out] globes 9 g5]al is also an important matt]4 ,a dirty globe looks v unsightly & absorbs mu* light4 ,! foll[+ po9ts %\ld be c>efully consid]$ 9 h&l+ & trimm+ lamps3 7#a7 ,be sure t y und]/& y\r sy/em & "k :e!r x is a con/ant-curr5t or a con/ant-pot5tial sy/em ( di/ribution4 ,) con/ant-curr5t sy/ems1 ! curr5t is con/ant & ! voltage ov] ! arc is regulat$2 :ile ) con/ant-pot5tial sy/ems1 ! voltage is con/ant & ! curr5t ?r\gh ! arc is regulat$4 7#b7 ,) con/ant-curr5t or s]ies lamps1 ! l9e mu/ nev] be op5$1 b mu/ be %unt$ ar\nd ! lamp if a lamp is to be cut out4 7#c7 ,) con/ant-pot5tial lamps1 ! lamp mu/ nev] be %unt$ b ! circuit mu/ be op5$4 7#d7 ,9 all cases ea* lamp %\ld be controll$ by a d\ble pole swit*4 7#e7 ,con/ant-pot5tial lamps _c be op]at$ )\t resi/ance 9 ! circuit2 ?is resi/ance may be 9 ! lamp itself or outside4 7#f7 ,nev] h&le high t5sion lamps )\t insulat+ y\rself f ! gr\nd2 & h&le live wires only ) "o h& at a "t4 7#g7 ,provide sp>k arre/]s = all op5-arc lamps 9 ! vic9ity ( inflammable mat]ial4 7#h7 ,nev] leave a lamp )\t globes :]e ! w9d c /rike x4 ,x w be bl[n out or fe$ (t51 ?us consum+ ! electrodes v fa/ & at ! same "t yield+ a v poor light4 ,gre5 light emitt$ by ! lamp w indicate t ! electrode hold]s are burn+4 ,/rong %ad[s ca/ upw>ds indicate a lamp burn+ 8upside d[n04 ,! positive electrode reta9s heat long] ?an ! negative4 ,! quality & size ( electrodes has mu* to d ) successful op]ation4 ,always use ! k9d ( electrodes recomm5d$ by ! mak] ( ! lamp4 ,direct-curr5t arc lamps d n require mu* 9 ! %ape ( reflectors z !y naturally ?r[ mo/ ( ! light d[nw>d1 :5 ! upp] electrode is positive4 ,!y %\ld z a rule be susp5d$ high4 ,alt]nat+-curr5t arc lamps ?r[ mo/ ( ! light f ! upp] electrode slightly bel[ ! horizontal & t f ! l[] electrode some:at above4 ,if ! light is want$ 9 a d[nw>d direction1 suitable reflectors mu/ be provid$4 ,te/+ ( ,arc ,lamps4--,! con/ant-pot5tial arc lamp is usually design$ = a c]ta9 curr5t & voltage4 ,! enclos$ arcs z a rule op]ate s+ly on #aaj volts1 :ile op5 arcs are run two 9 s]ies on ! same voltage4 ,9 ord] to te/ & see t ! voltage & curr5t are "r1 an ammet] & a voltmet] are ne$$4 ,! curr5t & voltage c bo? be adju/$ by alt]+ ! resi/ance1 :i* is always 9 s]ies ) su* lamps4 ,to get ! correct voltage ov] ! arc1 be sure to connect ! voltmet] to ! two electrode hold]s s z to elim9ate any o!r pot5tial drops t may affect ! read+4 ,te/+ ,c>bons4--,! color ( ! light & ! /ead9ess ( x c ( c\rse only be det]m9$ by actual op]ation te/s4 ,! arc obta9$ by us+ l>ge electrodes ) l[ curr5t d5sity is liable to rotate ar\nd ! electrodes1 burn un/eadily1 & flick]4 ,?is is due to ! fact t ! arc t5ds to e/abli% itself at ! po9t ( lea/ resi/ance4 ,9 ord] t ! arc may burn uni=mly1 ! curr5t d5sity mu/ be great en\gh to =ce all ( ! electrode po9ts into use4 ,z a rule ! be/ electrode is ! "o t has ! longe/ range f ! l[ voltage po9t ( hiss+ to ! high voltage po9t ( flam+4 ,) su* an electrode ! greate/ range 9 light c be obta9$ )\t ei!r ! hiss+ or ! flam+4 ,! same qualities t give an electrode long range1 z above1 also indicate its purity & if we make a te/ = range1 we %all !re=e at ! same "t make a te/ = purity4 ,! te/ = range c be c>ri$ out by any ord9>y h&-fe$ lamp4 ,to make x1 ! electrodes are ins]t$ & all[$ to burn until _! po9ts h assum$ ! prop] %ape4 ,! arc c !n be %ort5$ until ! famili> hiss+ s\nd is he>d4 ,note ! voltage at :i* ?is occurs1 be+ c>eful to h ! voltmet] connect$ s z to get ! voltage across ! arc only4 ,n[ sep>ate ! electrodes sl[ly until !y beg9 to flame & note ?is voltage4 ,ord9>ily ! hiss+ voltage w be ab\t #db & ! flam+ voltage ab\t #fb4 ,! great] ! diff]5ce betwe5 ! two1 ! bett] ! c>bons are assum$ to be4 ,9 mak+ comp>ative te/s on electrodes 9 ?is mann]1 c>e %\ld be tak5 t all ( ! conditions ( curr5t & size ( electrodes be ! same4 ,! te/ = comp>ative life ( electrodes is be/ made by arrang+ ! diff]5t electrodes s t ! same curr5t w pass ?r\gh ea* = ! same l5g? ( "t4 ,if ?is is done1 all t is necess>y is to weigh ! electrodes be=e & aft] burn+4 ,! approximate useful life ( an electrode c be easily det]m9$ by burn+ x = a /at$ l5g? ( "t1 not+ ! l5g? consum$ & comp>+ x ) ! l5g? available = burn+4 ,,*apt] ,,iii4 ,,projection4 ,sett+ & ,adju/m5t ( ,c>bons4--,to project a picture ^u a scre5 prop]ly is an art & requires close /udy & "s k ( all ! factors involv$4 ,! mo/ important factor is t ( ! light4 ,electric light is s univ]sally us$ at ! pres5t "t t x is h>dly necess>y to m5tion ! o!r s\rces ( illum9ation4 ,illu/ration3 ,,figure #g4 ,! electric curr5t ) :i* ! op]ator has to deal may be ei!r alt]nat+ or direct1 & ! k9d is ( great importance4 ,! color ( ! light obta9$ f a direct-curr5t arc is n only sup]ior to t obta9$ f an alt]nat+-curr5t arc b is obta9$ at a mu* l[] co/ s9ce1 z we %all pres5tly see1 x is s mu* m effici5t4 ,to project cle> :ite light ^u ! scre5 is impossible1 "s color w always be 9 x4 ,b by c>eful att5tion & by tra9+ himself to notice slight degrees ( color1 ! op]ator c le>n to r5d] a light :i* w be cle> en\gh to satisfy ! majority ( ! spectators4 ,9 ord] to obta9 ?is light1 ! s\rce f :5ce x comes %\ld be locat$ exactly 9 ! optical axis ( ! l5s sy/em2 t is1 a /raight l9e drawn ?r\gh ! c5t] ( all ( ! l5ses %\ld pass also directly ?r\gh ! c5t] ( ! arc z indicat$ 9 ,figure #g4 7,= compreh5sive treatise on l5ses1 see ,*apt] ,,xii47 ,illu/ration3 ,,figure #h4 ,illu/ration3 ,,figure #i4 ,illu/ration3 ,,figure #aj4 ,illu/ration3 ,,figure #aa4 ,illu/ration3 ,,figure #ab4 ,illu/ration3 ,,figure #ac4 ,mo/ ( ! light1 we h already se51 is emitt$ f ! crat] ( an arc ( :i* !re is b "o 9 a direct-curr5t arc & two 9 an alt]nat+ curr5t arc4 ,9 ord] to obta9 ! mo/ light ) ! lea/ exp5diture ( curr5t & heat 9 ! lamp h\se1 ! crat] mu/ be =m$ 9 su* a mann] z to face ! c5t] ( ! cond5s]s z ne>ly z possible4 ,s9ce1 h[ev]1 !re are always two electrodes & ! curr5t mu/ pass f "o to ! o!r1 ! crat] always t5ds to face ! l[] electrode if ! upp] "o is positive4 ,x is1 !re=e1 impossible to get ! full b5efit ( ! light = ! cond5s]2 we mu/ be satisfi$ ) gett+ a "p ( x1 & to d ?is su* sett+s ( electrodes z are %[n 9 ,figures #h to #ac are us$4 ,ab\t ! relative m]its ( ^! v>i\s sett+s !re is consid]able dispute & ! be/ advice t c be giv5 to any new com] 9 ! op]at+ l9e is to make 8 own exp]im5ts & f9d out = himself4 ,! fact t a c]ta9 po9t is mu* disput$1 alone indicates t !re is no exact k available2 = we v seldom h any diff]5ces ( op9ion ab\t ! ?+s t we c prove4 ,9 ! op]at+ l9e v mu* dep5ds ^u ! judgm5t ( ! op]ator4 ,electrode sett+ l t ( ,figure #h may be good = an op]ator :o is extremely c>eful & has a reliable ma*9e :i* requires a m9imum ( att5tion4 ,b x c readily be se5 t if ! top electrode 7 f$ a trifle too f> =w>d1 ! crat] w\ld =m und]nea? & ! l5ses w\ld receive b a small "p ( ! light4 ,ea* ( ! sett+s giv5 has its peculi>ities & x is be/ = any op]ator :o has n done s1 to try !m all out & f9d :i* "o be/ suits him & 8 conditions4 ,figures #h to #aj %[ ! sett+s us$ ) direct-curr5t arcs2 :ile ^? illu/rat$ by ,figures #aa to #ac are us$ ) alt]nat+-curr5t arcs4 ,) alt]nat+-curr5t arcs ! problem is ev5 m difficult ?an ) direct1 = we h "h two crat]s to deal )2 & if we wi% to use ! light f bo?1 we %all h to be v c>eful ab\t x4 ,if ! electrodes are n set exactly "r1 we may get a d\ble spot & poor illum9ation at ! c5t] ( ! scre54 ,p]haps mo/ op]ators w soon give up ! idea ( us+ ! light ( bo? crat]s & w settle d[n to an electrode sett+ some?+ l t %[n 9 ,a1 ,figure #g4 ,9 ?is sett+ bo? electrodes are angl$ & ! l[] "o is set a little ahead ( ! upp]4 ,?is has a t5d5cy to draw ! crat] ( ! upp] electrode =w>d1 ?us improv+ ! light on ! cond5s]2 b if ?is be c>ri$ too f>1 ! l[] electrode w ob/ruct ! l[] "p ( ! l5s4 ,! l[] electrode mu/ always be set s t x all[s all p>ts ( ! cond5s] to receive direct rays ( light f ! crat] ( ! upp]4 ,! electrode mu/ align p]fectly 9 ! v]tical plane z %[n 9 ,b1 ,figure #g1 or ! arc w move :ile burn+4 ,9 ord] to enable ! op]ator to arrange 8 electrodes at any angle & to br+ !m into ! c5t] ( ! optical sy/em1 arc lamps are made up 9 v>i\s ways z illu/rat$ 9 ,figures #ad to #ai4 ,! simpl] types are us$ only 9 /age light+ lamps :]e ! c5t]+ is n s important4 ,! m elaborate lamps are provid$ = motion picture arc lamps & all[ ( all necess>y adju/m5ts :i* are3 fe$ electrodes2 move lamps =w>d or back2 up or d[n2 sideways & angle electrodes4 ,:]e direct curr5t is us$1 ! upp] electrode mu/ be f$ approximately twice z fa/ z ! l[]2 b ) alt]nat+ curr5t1 !y bo? fe$ at practically ! same rate4 ,illu/ration3 ,,figure #ad4 ,figure #ad %[s a =m ( ,mc,intosh /]eopticon lamp4 ,illu/ration3 ,,figure #ae4 ,figure #ae is a ,kliegl lamp = op5 arc lamps4 ,illu/ration3 ,,figure #af4 ,figure #af is an ,edison lamp us$ = motion picture "w4 ,illu/ration3 ,,figure #ag4 ,figure #ag is a ,kliegl lamp us$ = focus+ purposes4 ,illu/ration3 ,,figure #ah4 ,figure #ah %[s ! ,p[]s lamp4 ,illu/ration3 ,,figure #ai4 ,figure #ai %[s "o ( ! ,motiograph ,company lamps4 ,optical ,sy/em4--,9 ,figure #bj we h ! complete optical sy/em ( ! mov+ picture or /]eopticon outfit4 ,! crat] ( ! arc lamp & ! c5t] ( ! objective l5s are at ! conjugate focal po9ts 7see ,optics7 & mu/ always be 9 ?is relation4 ,! size ( ! picture project$ ^u ! scre5 is gov]n$ entirely by ! focal l5g? ( ! objective l5s & ! di/ance ( ! scre5 f ?is l5s4 ,! %ort] ! focal l5g?1 ! great] w be ! bulg+ out or r\nd+ ( ! l5s1 & ! l>g] ! picture project$4 ,! objective l5s is always fitt$ ) an adju/+ device ( "s k9d by :i* x c be mov$ =w>d or back a little to focus ! picture prop]ly4 ,illu/ration3 ,,figure #bj4 ,9 ord] to project a picture prop]ly1 x is necess>y t ! c5t] ( ! arc or o!r illum9ant1 ! c5t] ( ! cond5s]s1 & ! c5t] ( ! objective1 all fall 9 "o /raight l9e z indicat$ 9 ,figure #bj4 ,! cond5s]s are provid$ = ! purpose ( ga!r+ & cond5s+ z _m ( ! scatt]+ light rays ( ! arc lamp z possible & br++ !m to be> ^u ! slide & ! objective4 ,! light us$ mu/ come ei!r f a reasonably small s\rce or f a l>g] s\rce f> en\gh away s t ! rays c be consid]$ z p>allel4 ,! focal po9t = p>allel rays w\ld1 h[ev]1 diff] some:at f t ( a po9t s\rce & su* illum9ation is seldom us$2 9 fact1 x is us$ only :]e special arrangem5ts are made = x4 ,"o ( ! pr9cipal po9ts to be borne 9 m9d 9 try+ to project a good cle> picture is to keep ! arc d[n to z small a po9t z is practicable4 ,a long arc c be tol]at$ only :5 x is absolutely impossible to obta9 suffici5t illum9ation f a %ort arc2 z1 = in/ance1 9 op]at+ ! ,k9emacolor ma*9es1 9 :i* f #hj to #ajj amp]es are us$ ) a v long arc4 ,! above exp$i5t is imp]ative because ! color$ discs ?r\gh :i* ! light mu/ pass absorb a great am\nt ( x & ! def9ition or outl9e ( ! picture is apt to be poor4 ,! position ( ! arc ) ref]5ce to ! cond5s]s is also an important po9t to consid]4 ,! focal l5g? ( ! cond5s]s det]m9es ! po9t at :i* ! arc mu/ be ma9ta9$4 ,! flatt] ! cond5s]s are1 ! f>!r away ! arc may be1 & ! less w be ! heat+2 b ?is position is accompani$ ) consid]able loss ( light4 ,= ! purpose ( projection we c use only ! light :i* /rikes ! cond5s]s direct f ! arc4 ,rays reflect$ by ! lamp h\se d n pass ?r\gh ! cond5s]s 9 ! same direction z ^? com+ directly f ! crat] & w n focus ) !m4 ,h5ce1 ! f>!r ! arc is f ! cond5s]s1 ! small] w be ! p]c5tage ( light us$2 ! %ort] ! focal l5g? ( ! cond5s]s1 ! clos] to !m mu/ ! arc be ma9ta9$1 & ! great] w be ! p]c5tage ( light us$4 ,b if ! light is br\ght too close1 !re w be undue heat+ ( ! cond5s]s & ^!1 especially ! "o ne>e/ ! light1 w be likely to break4 ,s great is ! heat produc$ t sometimes ! two l5ses are p>tially melt$ & weld$ toge!r4 ,?is is a frequ5t occurr5ce 9 cases :]e v heavy curr5ts are us$4 ,x mu/ be recall$ t ! heat produc$ is proportional to ! squ>e ( ! curr5t & t o!r ?+s be+ equal1 #hj amp]es w\ld produce f\r times ! heat ( #dj amp]es4 ,cond5s] breakage is q an important subject & "o ^u :i* !re is mu* argum5t among op]ators4 ,_m ( ! !ories held are1 h[ev]1 n plausible en\gh to m]it m5tion4 ,! pr9cipal cause is no d\bt ov]heat+ )\t all[+ suffici5t room = expansion 9 ! sett+4 ,no l5s %\ld ev] be set s t x does n move freely ev5 :ile x is hot4 ,ev5 if free :ile cold1 ! expansion1 :]e ! heat+ is great1 may be suffici5t to tight5 x 9 ! cas+1 & ?is is likely to cause breakage4 ,! be/ me?ods ( prev5t+ heat+ are3 a l>ge lamp h\se well v5tilat$ & cond5s]s ( su* focal l5g? z to all[ ! arc to be ma9ta9$ at "s di/ance f !m4 ,drafts ( air are (t5 giv5 z ! cause ( breakage1 b ! tru? ( ?is is r problematical4 ,!re is no d\bt t sudd5 contraction1 due to rapid cool+1 w\ld h a /rong t5d5cy to break !m2 b ! air 9 op]at+ rooms is n (t5 cold & is n likely to /rike ! l5s anyway4 ,x mu/ be not$ t x is usually ! inn] l5s1 :i* is ord9>ily enclos$1 t breaks4 ,illu/ration3 ,,figure #ba4 ,9 ! projection ( mov+ pictures !re are two important po9ts t mu/ always be consid]$4 7#a7 ! size ( ! spot on ! gate at :i* ! film appe>s1 & 7#b7 ! cle>ness ( ! field or light on ! scre54 ,by prop]ly adju/+ ! arc1 we c make ! spot any size we desire2 & ! small] we make x1 s long z x cov]s ! :ole ap]ture1 ! bright] ! light w be4 ,b if we make ?is spot too small1 we %all br+ 9 ! fr+e ( color :i* always appe>s at ! out] edge4 ,color ( ?is k9d is objectionable & mu/ be avoid$ z mu* z possible2 b x is n necess>y to g to extremes4 ,a little color+ w n be notic$ by ! audi5ce & w !re=e n be objectionable4 ,) a giv5 sy/em !re w ?us be a c]ta9 size ( spot :i* gives ! be/ results obta9able4 ,consid]+ t if ! spot is increas$ 9 size1 ! light becomes cle>] b also less int5se2 & t if ! spot is decreas$ 9 size1 ! light on ! scre51 ?\gh m brilliant1 is liable to %[ color+1 a good op]ator %\ld practice di/+ui%+ ! color+ & make himself z pr(ici5t 9 ?is art z possible4 ,! cu/om>y proportions ( spot & ap]ture are %[n 9 ,figure #ba4 ,color+ appe>s1 h[ev]1 f ano!r cause also1 viz41 improp] c5t]+ or adju/m5t ( ! arc lamp ) ref]5ce to ! cond5s]s4 ,if ! arc is n prop]ly adju/$1 b&s ( color su* z are indicat$ 9 ,figure #bb may appe> 9 any ( ! positions %[n4 ,?is is commonly spok5 ( z ! 8gho/01 & x mu/ be elim9at$4 ,x is n possible to get rid ( x entirely1 b by a little skill1 pati5ce1 & exp]i5ce1 x c be r$uc$ to a negligible am\nt4 ,:5 ! spot is "r & ! scre5 cle>1 ! picture may be focus$ by adju/+ ! objective l5s4 ,illu/ration3 ,,figure #bb4 ,to focus %>ply1 x is advisable to move ! l5s 9 "o direction until ! picture appe>s a trifle blurr$2 !n move x 9 ! opposite direction until at ?is po9t !re is also a blurr$ picture4 ,! exact focus w be at a po9t half way betwe5 ! two4 ,to focus ! l5s 9 ?is mann] is important :]e ! slide or film has "s play1 z :5 ! ap]ture plate on a ma*9e is worn & all[s ! film "s movem5t4 ,curr5t ,requir$4--,! measurem5t ( ! c&le p[] ( arc lamps has nev] be5 satisfactorily tak51 & ! difficulties enc\nt]$ 9 det]m9+ x = a project+ arc are especially great because only a small "p ( ! total light c be utiliz$ & ?is is con/antly v>y+4 ,! light may1 h[ev]1 be assum$ z proportional to ! wattage ( ! arc1 h5ce1 we c be/ judge x by not+ ! volts & amp]es4 ,:]e a v /rong light is desirable1 ! arc is usually drawn out to "s l5g?2 & z !re is a rise 9 voltage1 ) a long arc1 9 su* a case1 ! light increases at a great] rate ?an ! amp]age4 ,9 ord9>y projection "w1 ! arc is kept q %ort because ( ! bett] def9ition obta9able by ! use ( su* an arc2 & we may assume t ! light obta9$ is ne>ly directly proportional to ! amp]age4 ,?is relation ( light & ! curr5t input to ! lamp w be practically correct1 especially if ! size ( ! electrodes *os5 is proportional to ! amp]age4 ,curr5t ,requir$ = ,project+4--,! value ( ! curr5t to be us$ = projection is a matt] ( "s dispute among op]ators & probably mu* ( ?is is caus$ by ! abs5ce ( ammet]s1 mo/ op]ators m]ely guess+ at :at !y are us+1 or be+ guid$ by m>k+s ( rheo/ats or comp5sators4 ,9 mo/ cases some?+ l #dj amp]es seems to be ! rule4 ,9 ord] to give ! read] a cle> und]/&+ ( ! !oretical requirem5ts1 ,table ,i has be5 prep>$4 ,?is table is n int5d$ to act z an accurate guide1 b m]ely to %[ ! amp]age !oretically requir$ ) diff]5t siz$ pictures1 to br+ ab\t ! same illum9ation 9 ea* case4 ,,table ,i4 ,,curr5t ,,requir$ ,,= ,,diff]5t ,,size ,,pictures4 ---------------------------------------- --------- ,greate/ ,amp]es ,dim5sion ,area ----------------------- ( ,picture ,illum9at$4 ,direct ,alt]nat+ 9 feet4 ,curr5t4 ,curr5t4 ---------------------------------------- -------- #e #ci #h #ab #f #ef #aa #af #g #gg #ae #bb #h #ajj #bj #cj #i #abg #be #cg #aj #aeg #ca #de #aa #ahi #ch #eg #ab #bbd #de #fg #ac #bfj #eb #gh #ad #cjg #fj #ij ---------------------------------------- -------- ,two errors are v common 9 ! computation ( ! light int5sity = a giv5 picture3 7#a7 ! l5g? ( ?r[ gov]ns ! amp]age2 & 7#b7 ! amp]age dep5ds ^u ! actual space to be illum9at$4 ,app>5tly only an oblong squ>e ( exactly ! proportions ( ! ap]ture 9 ! ma*9e is illum9at$1 b 9 reality ! light mu/ be spread out s t its total illum9ation cov]s a circle enclos+ ! actual visible picture4 ,?is is illu/rat$ 9 ,figure #bc :]e ! enclos$ oblong squ>e repres5ts ! space illum9at$ on ! scre5 & ! circle repres5ts ! area ov] :i* ! light mu/ be spread4 ,! portion %[n by %ad+ is ne>ly equal to ! cle> portion & %[s t half ( ! light is wa/$ s9ce x is block$ out by ! cool+ plate 9 ! ma*9e or ! framework ( ! slides4 ,) increas+ size ( picture1 ! light is1 h[ev]1 dim9i%$ 9 proportion to ! area ( ! circle & n 9 proportion to ! area ( ! picture4 ,if1 = in/ance1 ! picture 7 to reta9 its wid? & be r$uc$ 9 height by "o half1 or ev5 m1 !re w\ld /ill be ab\t ! same quantity ( illum9ation requir$4 ,= ?is reason we h1 9 ,table ,i1 giv5 only ! maximum dim5sion ( ! picture & h bas$ ! amp]age calculation ^u ! area ( ! circle :i* encloses ! picture4 ,illu/ration3 ,,figure #bc4 ,! values giv5 are less ?an are g5]ally us$ = small pictures & m ?an are g5]ally us$ = l>ge pictures4 ,z a rule mu* light is wa/$ on small pictures because ! app>atus is at h& to deliv] x2 ) l>ge pictures1 ! illum9ation is (t5 poor because trans=m]s & rheo/ats are seldom fitt$ to deliv] m ?an #fj amp]es4 ,mu* light c easily be wa/$ if ! picture is made too bright4 ,9 su* a case1 mu* ( ! light is reflect$ back to ! auditorium & ?is 9 turn makes ! picture appe> less bright4 ,9 det]m9+ ! amp]age necess>y to %[ a picture prop]ly1 ! foll[+ conditions mu/ be borne 9 m9d1 any "o ( :i* may appreciably affect ! result3 7#a7 ,nature ( ,scre54--,a good scre5 w reflect m light ?an a poor "o4 7#b7 ,size ( ,picture4--,! l>g] ! picture1 ! m light w be requir$4 7#c7 ,"* ( ,film4--,"s films are v d>k & require extra illum9ation4 7#d7 ,h\se ,illum9ation4--,9 "s cities ! law requires fairly bright illum9ation ( auditoriums & ?is makes ! picture appe> less bright4 7#e7 ,atmosph]e4--,:]e ! air is full ( du/1 or :]e smok+ is all[$2 mu* light w be absorb$4 7#f7 ,l5ses4--,"s l5ses are badly discolor$ & absorb mu* light4 7#g7 ,electrodes & ,electrode ,sett+4--,?is is a v important factor & "o :i* a good op]ator w nev] neglect4 ,selection ( ,l5ses4--,^u ! prop] selection ( l5ses dep5ds v mu* ! quality ( ! picture4 ,! size ( ! picture1 "u giv5 circum/ances1 dep5ds entirely ^u ! focal l5g? ( ! objective4 ,) a giv5 di/ance betwe5 l5s & scre5 !re is practically b "o size ( picture obta9able4 ,if we wi% to obta9 a picture ( ano!r size by ! use ( ! same l5s1 ?is c be done only by sacrific+ ! def9ition & _h bett] n be attempt$4 ,v l>ge pictures are desirable only 9 l>ge halls 9 :i* portions ( ! audi5ce are v f> f ! scre54 ,su* a picture requires v mu* light &1 on acc\nt ( its size1 %[s _m imp]fections to ^? :o sit 9 ! front r[s4 ,x is bett] to limit ! size ( ! picture to "o :i* c be easily illum9at$1 & ?us avoid su* imp]fections4 ,,table ,,ii4 ,,motion ,,picture ,,l5ses4 ,,table ,,%[+ ,,size ,,( ,,scre5 ,,image ,,:5 ,,mov+-,,picture ,,films ,,are ,,project$4 ,size ( ,mat op5+ #aa-af #ae-af in*4 ---------------------------------------- ----------------- ,e4,e4 #ae #bj #be #cj #ce #dj #de #ej #fj #gj #hj #ij #ajj ,94 ft4 ft4 ft4 ft4 ft4 ft4 ft4 ft4 ft4 ft4 ft4 ft4 ft4 ---------------------------------------- ----------------- #b-a_/h #d4h #f4d #h4j #i4faa4cab4iad4eaf4a #f4e #h4gaa4jac4bae4dag4fai4hbb4j ---------------------------------------- ----------------- #b-a_/b #e4d #f4h #h4b #i4faj4iab4cac4gaf4d #g4d #i4caa4bac4aad4iaf4hah4gbb4d ---------------------------------------- ----------------- #c #d4e #e4g #f4h #h4j #i4aaj4caa4dac4gaf4j #f4b #g4g #i4caj4iab4dad4jae4fah4gba4h ---------------------------------------- ----------------- #c-a_/b #d4i #e4h #f4h #g4h #h4h #i4haa4gac4gae4g #f4f #h4j #i4caj4fab4jac4caf4jah4gba4d ---------------------------------------- ----------------- #d #d4b #e4a #f4j #f4h #g4g #h4eaj4cab4jac4gae4d #e4h #g4j #h4a #i4caj4eaa4fad4jaf4cah4gba4j ---------------------------------------- ----------------- #d-a_/b #d4e #e4c #f4b #f4h #g4g #i4aaj4fab4bac4gae4d #f4b #g4b #h4d #i4caj4eab4dad4eaf4fah4gba4j ---------------------------------------- ----------------- #e #d4h #e4d #f4a #f4h #h4b #i4faj4iab4cac4g #f4e #g4d #h4d #i4caa4bac4jad4iaf4hah4g ---------------------------------------- ----------------- #e-a_/b #d4c #d4i #e4f #f4b #g4d #h4g #i4iaa4bab4d #e4i #f4g #g4f #h4daj4baa4iac4fae4cag4j ---------------------------------------- ----------------- #f #d4e #e4a #e4g #f4h #h4j #i4aaj4caa4d #f4b #g4j #g4g #i4caj4iab4dad4jae4f ---------------------------------------- ----------------- #f-a_/b #d4g #e4b #f4c #g4c #h4d #i4faj4f #f4d #g4a #h4faj4jaa4dac4jad4e ---------------------------------------- ----------------- #g #d4d #d4i #e4h #f4h #g4h #h4h #i4h #f4j #f4f #h4j #i4caj4fab4jac4c ---------------------------------------- ----------------- #g-a_/b #d4e #e4d #f4d #g4c #h4b #i4a #f4b #g4d #h4gaj4jaa4bab4c ---------------------------------------- ----------------- #h #e4a #f4j #f4h #g4g #h4e #g4j #h4a #i4caj4eaa4f ---------------------------------------- ----------------- ,example3 ,) a l5s ( #e-a_/b in* focus at a di/ance ( #ce ft4 ! scre5 image w be #d4ce4i2 at #dj ft41 #d4if4g2 at #de ft41 #e4fg4f2 etc4 ,note3 ,:5 ord]+ l5ses1 give size ( picture want$1 & di/ance f ma*9e to scre54 ,,table ,,iii4 ,,/]eopticon ,,l5ses4 ,,table ,,%[+ ,,size ,,( ,,scre5 ,,image ,,:5 ,,lant]n ,,slides ,,are ,,project$4 ,size ( ,mat op5+ #b-c_/d #c in*es4 ---------------------------------------- ----------------- ,e4,f4 #ae #bj #be #cj #ce #dj #de #ej #fj #gj #hj #ij #ajj ,94 ft4 ft4 ft4 ft ft4 ft4 ft4 ft4 ft4 ft4 ft4 ft4 ft4 ---------------------------------------- ----------------- #e #h4jaj4hac4eaf4cai4j #h4haa4had4hag4hbj4h ---------------------------------------- ----------------- #e-a_/bg4c #i4hab4cad4hag4cai4h #g4iaj4gac4daf4aah4hba4f ---------------------------------------- ----------------- #f #f4f #h4iaa4bac4eae4hah4abj4d #g4c #i4hab4cad4hag4cai4hbb4c ---------------------------------------- ----------------- #f-a_/bf4a #h4baj4dab4ead4faf4gah4h #f4g #i4jaa4cac4fae4iah4bbj4e ---------------------------------------- ----------------- #g #e4g #g4f #i4faa4fac4eae4eag4eai4d #f4b #h4caj4eab4fad4haf4iai4jba4b ---------------------------------------- ---------------- #g-a_/be4c #g4a #h4iaj4hab4fad4daf4cah4a #e4h #g4h #i4haa4hac4hae4hag4hai4h ---------------------------------------- ----------------- #h #f4f #h4daj4aaa4hac4eae4bag4jbj4d #g4c #i4aaa4jab4iad4haf4fah4ebb4c ---------------------------------------- ----------------- #h-a_/b #f4b #g4i #i4eaa4aab4gad4caf4jai4b #f4h #h4faj4cab4aac4iae4fag4dbj4i ---------------------------------------- ----------------- #i #e4i #g4d #h4iaj4eab4jac4eae4aah4aba4a #f4d #h4a #i4haa4dac4aad4haf4dai4hbc4a ---------------------------------------- ----------------- #i-a_/b #e4f #g4j #h4e #i4iaa4dab4had4bag4abj4j #f4a #g4f #i4baj4hab4dad4jae4eah4gba4i ---------------------------------------- ----------------- #aj #e4c #f4f #h4j #i4daj4hab4bac4eaf4cai4jba4h #e4h #g4c #h4haj4caa4hac4cad4hag4hbj4hbc4h ---------------------------------------- ----------------- #ab #e4e #f4f #g4h #h4iaj4aaa4bac4eae4hah4abj4d #f4j #g4c #h4e #i4haa4jab4cad4hag4cai4hbb4c ---------------------------------------- ----------------- #ad #e4f #f4f #g4f #h4f #i4faa4fac4eae4eag4eai4d #f4b #g4c #h4c #i4daj4eab4fad4haf4iai4jba4b ---------------------------------------- ----------------- #af #e4h #f4f #g4e #h4daj4aaa4hab4eae4bag4j #f4c #g4c #h4b #i4aaa4jab4iad4haf4fah4e ---------------------------------------- ----------------- #ah #e4a #e4i #f4f #g4d #h4iaj4eab4jac4eae4a #e4f #f4d #g4c #h4a #i4haa4dac4aad4haf4d ---------------------------------------- ----------------- #bj #e4c #f4j #f4f #h4j #i4daj4hab4bac4e #e4h #f4e #g4c #h4haj4caa4hac4cad4h ---------------------------------------- ----------------- #bb #e4d #f4j #g4c #h4e #i4haa4jab4c #e4i #f4f #g4i #i4caj4gab4jac4d ---------------------------------------- ----------------- #bd #e4e #f4f #g4h #h4iaj4aaa4b #f4j #g4c #h4e #i4haa4jab4c ---------------------------------------- ----------------- ,example3 ,) l5s ( #aj-;in* focus at a di/ance ( #bj ft4 ! scre5 image w be #e4ce4h2 at #be ft41 #f4fg4c2 at #cj ft41 #h4jh4h2 at #ej ft41 #ac4ead4h42 etc4 ,table ,,ii %[s ! size ( picture obta9able f films1 & ,table ,,iii1 ! size obta9able f lant]n slides4 ,s9ce ! slide pictures mu/ be %[n ^u ! same scre5 z ! film1 x c be se5 f ! tables t l5ses ( diff]5t focal l5g? mu/ be us$ = ! two4 ,! aim %\ld be to get ! two pictures to mat* z ne>ly z possible1 b z !y are n ( ! same proportions1 x is impossible to mat* !m exactly 9 bo? directions4 ,! ne>e/ approximation t c be br\ght ab\t by /&>d l5ses is illu/rat$ 9 ,figure #bd4 ,! heavy l9es %[ ! dim5sion ( ! picture project$ ?r\gh ! film1 & ! light & dott$ l9es %[ ! dim5sions obta9able by ! use ( slides4 ,if ! slide picture is mat*$ to ! height ( ! film1 x w be consid]ably n>r[]2 if x is mat*$ to ! sides1 x w be consid]ably high]4 ,x w\ld ( c\rse be possible to trim d[n slides s t ! dim5sions ( ! two pictures w\ld be exactly alike2 b z mo/ all /]eopticon slides belong to travel+ actors ?is is n practicable4 ,illu/ration3 ,,figure #bd4 ,if ! focal l5g? ( a l5s is n kn[n1 x c easily be measur$ by focus+ "s di/ant object1 an inc&esc5t lamp = in/ance1 aga9/ ! wall ( a room or aga9/ "s scre5 plac$ ^u a table z %[n 9 ,figure #be4 ,9 ! case ( a s+le plano-convex l5s1 ! measurem5ts mu/ be made f bo? sides--fir/ "o side turn$ t[>d ! light1 & !n ! o!r4 ,!re w always be "s diff]5ce betwe5 ! two measurem5ts & we mu/ take ! mean ( ! two4 ,to get ! measurem5t accurately1 place a rule ^u a table & set up "s suitable object ^u :i* ! picture c be project$4 ,turn ! flat side ( ! l5s t[>d ! scre5 & focus "s di/ant object by mov+ ! l5s to a po9t at :i* ! object select$ w appe> cle>ly ^u ! scre54 ,note ! di/ance ( ! flat side ( ! l5s f ! picture4 ,n[ turn ! l5s half way ar\nd & focus aga9 9 ! same mann]1 not+ ?is di/ance also4 ,add ! two measurem5ts & divide by two2 ?is w give ! focal l5g? ( ! l5s4 ,9 ! case ( an objective l5s1 we mu/ turn ! side :i* bulges out mo/ t[>d ! scre5 & focus 9 ! same mann]4 ,illu/ration3 ,,figure #be4 ,) ! objective l5s we h two possible focal l5g?s to consid]4 ,if we measure f ! c5t] ( ! l5s to ! scre51 we %all obta9 :at is call$ ! equival5t focal l5g? 7usually abbreviat$ ,e4,f4 or e4f474 ,if1 in/ead1 we take measurem5ts f ! face ( ! l5s ne>e/ ! scre51 we %all obta9 :at is t]m$ ! back focus1 or b4f41 ( ! l5s4 ,9 all cases x is important1 :5 ord]+1 to /ate :i* ( ! two is meant4 ,l5ses may also be te/$ = *romatic & sph]ical ab]ration4 ,*romatic ab]ration is ! fault ( %[+ colors unduly4 ,x is impossible to avoid a fr+e ( color :5 us+ only a s+le l5s1 b :]e we h a complete optical sy/em1 consi/+ ( two cond5s]s & an objective1 x mu/ be possible to adju/ ! comb9ation s t practically no color is visible4 ,sph]ical ab]ration is be/ te/$ = by lay+ out v accurately1 z 9 ,figure #bf1 a set ( small squ>es ^u "s mat]ial t w n be damag$ by ! heat ( ! lamp--mica = in/ance--& project+ ?is ^u ! scre54 ,if ! l5ses are all good1 ! l9es w all appe> squ>e2 if ! l5ses are poor1 ! l9es w appe> curv$ a little1 or p]haps consid]ably4 ,illu/ration3 ,,figure #bf4 ,! diamet] ( ! ord9>y cond5s] l5s is #d-a_/b in*es4 ,small] l5ses ?an ?is _c well be us$ because !y w\ld n cov] ! diagonal ( lant]n slides4 ,a v common focal l5g? ( cond5s] is #f-a_/b in*es4 ,!re is no v accurate relation necess>y betwe5 ! focal l5g? ( cond5s] & objective4 ,!re is consid]able diff]5ce ( op9ion on ?is subject & mu* ( x is induc$ by ! possibility ( cond5s] breakage :i* is increas$ by us+ cond5s]s ( %ort focal l5g?1 b 9 ?is case1 z 9 _m o!rs1 ! op]ator mu/ f9d out by 8 own exp]im5ts4 ,a v good plan--s9ce1 on acc\nt ( breakage1 extra l5ses mu/ be c>ri$ anyway--is to c>ry two #g-a_/b-;in* & two #f-a_/b-;in* cond5s]s & exp]im5t ) ^!4 ,! two ( ! same diamet]s may be tri$ toge!r & also ^? ( diff]5t focal l5g?s1 us+ ! "o ( %ort] focal l5g? ei!r 9 front ( or beh9d ! o!r4 ,,h9ts ,,on ,,managem5t ,,( ,,project+ ,,arcs4 ,be=e />t+ to "w ab\t ! lamp1 be sure ! swit* is (f4 ,see t ! lamp h\se is clean & sp>k tight4 ,! gauze provid$ at ! top mu/ be kept free f dirt & c>bon a%1 or ! h\se itself may get too hot4 ,! h\se %\ld be ( su* dim5sions1 relative to ! l5g? ( electrodes us$1 t ! latt] _c t\* ei!r at ! top or bottom & ?us gr\nd ! circuit on ! lamp h\se & possibly burn a hole 9 x4 ,see t y\r lamp me*anism is well align$ s t electrodes c5t] at all positions4 ,all ( ! screws & adju/m5ts %\ld be well lubricat$ frequ5tly4 ,! heat 9 ! lamp h\se soon evaporates all lubrication4 ,:]e lamps are us$ mu* & c>ry heavy curr5ts1 ! lead+ 9 wires w probably ne$ reconnect+ ab\t once a week4 ,x is be/ to reconnect !m "s "t be=e !y burn (f r ?an be oblig$ to d ?is dur+ a %[4 ,see t y\r pol>ity is "r4 ,) direct curr5t1 ! upp] electrode w reta9 its heat long] ?an ! l[] if connections are made prop]ly4 ,) alt]nat+ curr5t ! pol>ity is immat]ial4 ,always po9t y\r electrodes1 especially ! l[]4 ,if ! l[] electrode is n po9t$1 x w int]f]e ) ! light ( ! crat]4 ,! recomm5dations = sizes ( upp] & l[] electrodes v>y some:at b run mo/ly to #e_/h in* = upp] & #a_/b in* = l[]4 ,! size dep5ds v mu* ^u ! curr5t us$4 ,if ! electrodes are too l>ge1 ! arc w travel ar\nd ! outside & yield a poor & unev5 light4 ,always use cor$ c>bons = alt]nat+ curr5t4 ,! be/ l5g? = electrodes is ab\t #f in*es1 if !y d n /rike ! lamp h\se4 ,not* ! c>bon electrode a little be=e attempt+ to break x (f4 ,_m op]ators are 9 ! habit ( wat*+ ! arc1 op5+ ! lamp-h\se door to look at x4 ,n only is ?is injuri\s to ! eyes b x also int]f]es ) prop] judgm5t ( ! illum9ation ( ! picture4 ,a bett] way is to pun* a v small hole 9 ! lamp h\se exactly opposite ! arc4 ,ov] ?is op5+ a l5s may be plac$1 & a picture ( ! arc may be ?r[n aga9/ a wall or scre5 set up = t purpose4 ,a picture ( ! arc is also obta9able 9 ano!r way3 ,if ! lamp is once set exactly "r1 a cross may be pa9t$ at ! prop] place on ! scre5 :i* w indicate ! exact po9t :]e ! arc %\ld be ma9ta9$4 ,! arc w ( c\rse appe> inv]t$4 ,ano!r me?od ( keep+ ! arc always 9 view )\t inconv5i5ce consi/s 9 arrang+ a small mirror1 at an angle to ! peep glass 9 ! door1 s t x w reflect ! arc t[>ds ! op]ator4 ,an adju/able resi/ance %\ld always be kept 9 rea* s t ! curr5t may be v>i$ to suit diff]5t films or /]eopticon lamps4 ,keep y\r h&s z free f c>bon du/ z possible4 ,?is du/ is responsible = mu* damage to films4 ,,*apt] ,,iv4 ,,motion ,,pictures4 ,/rictly speak+ !re are no pictures ( motion4 ,:at we see z su* is simply an optical illusion4 ,?is illusion is produc$ by pres5t+ a s]ies ( pictures ( an object 9 a sy/ematic mann]1 ea* picture %[+ "s slight *ange f ! prec$+ "o4 ,if ^! *anges be all 9 a c]ta9 direction & br\ght be=e our eyes 9 regul> ord]1 we %all p]ceive ! appe>ance ( motion 9 t direction4 ,su* pictures may be made by means ( photography4 ,a v simple =m ( motion picture is made up 9 ! =m ( a small book conta9+ a numb] ( leaves t may be run (f "u ! f+] ( ! hold]4 ,if ^! leaves conta9 su* a s]ies ( pictures z is m5tion$ above1 ! hold]1 on manipulat+ !m prop]ly1 w see motion reproduc$ q naturally4 ,! mann] 9 :i* ! illusion ( motion is produc$ c p]haps be/ be illu/rat$ by ,figure #bg4 ,"h we h an ord9>y film1 or x may be any piece ( :ite pap]1 ^u :i* are drawn a s]ies ( black dots z %[n4 ,if ?is film--! obs]v] be+ able to see only t "p 9 ! ap]ture ,a--be drawn d[nw>d ! l5g? ( "o section v quickly2 all[$ to re/ a mom5t2 !n1 9 ! same mann]1 be drawn d[n ano!r section2 & ?is process repeat$ at prop] spe$1 until ! full l5g? ( ! film has pass$ ! ap]ture1 we %all h receiv$ ! impression t ! black dot mov$ f ! l[] left-h& corn] to ! upp] "r-h& corn] ( ! ap]ture4 ,9 ord] t su* an illusion might be p]fect1 we %\ld h to move ! film s rapidly t ! eye w\ld n p]ceive ! movem5t4 ,?is is n possible except ) v weak illum9ation & we %\ld actually1 9 ! above exp]im5t1 receive a blurr$ impression1 because we c\ld n help see+ ! dots :ile !y 7 mov+1 & our eyes w\ld behold a mixture ( /ation>y & mov+ dots4 ,9 ord] to produce ! impression ( p]fect motion1 x is necess>y to %ut (f ! light dur+ ! "t t ! film is actually 9 motion4 ,?us1 p>adoxical z x may seem1 9 ord] to simulate motion1 we mu/ h ! object :i* is to appe> 9 motion always p]fectly /ill be=e our eyes4 ,illu/ration3 ,,figure #bg4 ,9 ord] t we may n notice t ! film is out ( sight1 x mu/ be mov$ v quickly4 ,! actual "t dur+ :i* ! picture on ! av]age film is hidd5 f view1 & 9 :i* ! picture is *ang$1 is ab\t #a_/hj? ( a second & ! "t dur+ :i* ! picture is /ation>y is ab\t #d_/hj? ( a second4 ,! possibility ( ! illusion ( motion pictures dep5ds ^u a faculty ( ! eye kn[n z p]si/5ce ( vision4 ,! eye reta9s an impression = some?+ l #a_/be? ( a second4 ,:5 an object is 9 motion1 we see1 !re=e1 n only "o position ( ! object b all positions ( x dur+ ! "t ( p]si/5ce ( vision4 ,?is "t v>ies some:at ) ! int5sity ( ! light or ! impression made ^u ! eye4 ,if x is equal to #a_/be? ( a second 9 ! case ( a ball ?r[n at ! rate ( "o hundr$ feet p] second1 !n we %\ld see1 in/ead ( "o ball1 a l>ge numb] ( balls m]g+ imp]ceptibly into "o ano!r1 or1 9 o!r words1 a /reak ( balls f\r feet long4 ,?us1 9 actual life1 we obta9 f ! mov+ ball b a blurr$ impression4 ,we see ?us t 9 ord] to produce ! impression ( motion1 we mu/ pres5t ! picture to ! eye long en\gh to /imulate x prop]ly2 we mu/ v quickly remove t picture & sub/itute ano!r diff]+ to a slight ext5t f ! =m]2 & we mu/ repeat ?is process a numb] ( times4 ,! ord9>y mov+ picture film conta9s #af pictures p] foot1 & is run (f at ! rate ( ab\t #fj feet p] m9ute1 s t 9 "o m9ute1 we see #ifj diff]5t pictures4 ,9 ord] to make motion visible1 we mu/ br+ x )9 a c]ta9 spe$ limit4 ,?us1 to %[ ! motion ( a swiftly ?r[n ball 9 detail1 we mu/ make x appe> to move m sl[ly ?an x really does2 & to %[ ! developm5t ( a gr[+ plant1 x mu/ appe> to gr[ mu* fa/] ?an x actually does4 ,bo? ( ^! requirem5ts c easily be fulfill$ by ! motion picture cam]a & ! project+ ma*9e4 ,a man1 walk+ at ! rate ( ?ree miles an h\r1 displaces himself ab\t ?ree in*es dur+ ! "t ( ! exposure ( "o picture1 or #a_/af? ( a second4 ,at ?is rate we obta9 ! impression ( ev5 & cont9u\s motion unless he be too close to ! cam]a4 ,9 ord] to obta9 pictures ( o!r objects mov+ at fa/] or sl[] rates1 we mu/ take !m at int]vals 9 ord] t ! displacem5t betwe5 pictures w be ab\t ! same or at lea/ n any m4 ,?is means t pictures ( rapidly mov+ objects mu/ be tak5 at %ort int]vals & ^? ( sl[ly mov+ objects1 at long int]vals4 ,a k]nel ( corn develops into a /alk six feet high 9 ab\t n9ety days4 ,if a photograph ( ?is is tak5 e day dur+ its gr[? & ^! pictures arrang$ 9 prop] ord]1 !y w be run (f at normal spe$ 9 less ?an six seconds1 ?us %[+ u 9 six seconds ! gr[? :i* actually takes place 9 n9ety days4 ,! motion picture cam]a enables u n only to produce ! illusion ( motion1 b to see 9 detail :at actually takes place 9 connection ) ! mov+ object at any in/ant4 ,if we take pictures ( a runn+ horse1 = in/ance1 at %ort en\gh int]vals1 we %all be able to see1 on ! films1 j h[ he holds or places 8 feet or any o!r "p ( 8 body at any "t4 ,9 ord] to obta9 a p]fect picture simulat+ motion1 we mu/ pres5t ! fir/ picture long en\gh to /imulate ! eye2 !n we mu/ %ut (f ! light1 remove ! fir/ picture1 & sub/itute ! second2 remove ! second & sub/itute ! ?ird1 etc41 z long z desir$4 ,dur+ ! "t t ! light is %ut (f1 ! fir/ picture mu/ p]si/ 9 our vision until ! new "o has appe>$4 ,! two pictures ?us mix until ! fir/ "o has fad$1 & ?us we obta9 ! illusion ( motion4 ,if ! bright picture rema9s too long1 ! pupil contracts--z expla9$ 9 ! *apt] on ,optics--& :5 next ! light is %ut (f1 ! d>kness is noticeable & gives rise to ! disagreeable ph5om5on ( flick]4 ,9 ord] to prev5t ?is ov]-/imulation ( ! eye1 ! long p]iod ( exposure is int]rupt$ by a %utt] at lea/ once &1 9 "s cases1 two times2 & "s ma*9es are equipp$ ) a ?ree-blade %utt]4 ,?is ?ree-blade %utt] has a wide blade :i* %uts (f ! light :ile ! film is 9 motion & two n>r[] blades :i* pass across ! light dur+ ! "t t ! film is /ation>y1 to prev5t ! ov]-/imulation ( ! eye4 ,color$ ,pictures4--,!re are two g5]al me?ods ( produc+ color$ motion pictures3 ,"o is t ( h& color+ or t9t+1 & ! o!r is :at is kn[n z ! ,k9emacolor process4 ,9 ! latt] process1 no color :atev] is us$ on ! film2 ! color+ is suppli$ by a %utt] ) a gre5 & a r$ blade :i* are alt]nately ?ru/ into ! light by :i* ! picture is project$ ^u ! scre54 ,9 ord] t ?is process may be us$1 ! film pictures mu/ fir/ be tak5 ?r\gh scre5s ( correspond+ color4 ,! film 9 ! ,k9emacolor cam]a1 or project+ ma*9e1 mu/ run at m ?an d\ble ! spe$ ( t :i* is us$ 9 ! ord9>y process2 & ea* alt]nate picture mu/ be photograph$ ?r\gh a r$ scre52 ! o!rs1 ?r\gh a gre5 scre54 ,! r$ scre5 w all[ only r$ light to pass2 h5ce1 any "p ( an object t conta9s no r$ w n affect ! photographic emulsion4 ,simil>ly1 ! gre5 scre5 w all[ only gre5 light to pass2 & su* p>ts ( ! objects z conta9 no gre5 w n affect ! emulsion4 ,! alt]nate sections ( film w ?us be entirely diff]5t f ea* o!r4 ,9 ord] to reproduce ! orig9al color ( ! object ^u ! scre51 x is b necess>y to arrange t ! pictures %all 9 turn be project$ ?r\gh ! same or simil> color scre5s4 ,9 ord] to accompli% ?is1 ! ,k9emacolor ma*9e has1 9 addition to ! regul> %utt] :i* cuts (f ! light dur+ ! "t ! film is 9 motion1 an additional two-w+ %utt] :i* ins]ts ! prop]ly color$ scre5s be=e ea* picture1 z x comes to a /&/ill 9 ! film w9d[4 ,?us we see 9 alt]nation1 a r$ picture & a gre54 ,p]si/5ce ( vision1 :i* is expla9$ 9 ,*apt] ,,ix1 helps u to mix ! two colors & we see ! object approximately 9 its own colors4 ,! color effect is n v good1 ow+ p>tly to ! fact t only two colors are us$4 ,if ! ?ree prim>y colors--r$1 blue1 & yell[--c\ld be us$1 ! effect w\ld d\btless be bett]2 b ! complications w\ld be multipli$4 ,9 ord] to get ! be/ results ) ! ,k9emacolor process1 colors ( a c]ta9 %ade are us$ & ! size & dep? ( color+ 9 ! two %utt]s is v>iable4 ,"o ( ! colors is adju/able & mu/ be s arrang$ t :5 ! ma*9e is run )\t film1 x w ?r[ approximately :ite light ^u ! scre54 ,! high spe$ ) :i* ! film mu/ be run makes x impossible to turn ! ma*9e by h& & x is always motor-driv54 ,! color$ %utt]s are con/antly 9 ! light & absorb a l>ge portion ( x & ?is mu/ be comp5sat$ = by an extraord9>y high amp]age4 ,?is process requires m ?an two times z mu* curr5t z ! ord9>y projection ( black & :ite pictures4 ,9 ord] to obta9 ! greate/ possible am\nt ( light1 op]ators usually run a v long arc & ?is (t5 results 9 imp]fect def9ition4 ,9 arrang+ = an exhibition1 x is important t ! film & ! color$ scre5s be correctly plac$ ) ref]5ce to ea* o!r2 to facilitate ?is1 an id5tify+ m>k is plac$ on ! side ( "o ( ! colors4 ,,*apt] ,v4 ,,! ,,motion-,,picture ,,ma*9e4 ,a diagrammatic sket* ( ! ess5tials ( a good motion picture ma*9e is giv5 9 ,figure #bh4 ,?is does n repres5t any ma*9e 9 p>ticul> & no ma*9e exactly l x w be f\nd2 x does1 h[ev]1 %[ ! !oretical elem5ts necess>y to ! projection ( motion pictures & ! usual safety devices ) :i* /&>d ma*9es are provid$4 ,z a v>iation f ,figure #bh1 ! exact me?od ( ?read+ ! film ?r\gh ! ,edison ma*9e is giv5 9 ,figure #bi4 ,9 ,figure #bh1 ! p>ts are designat$ z foll[s3 ,a--fe$ reel or upp] reel ,b--fe$ reel magaz9e or upp] magaz9e ,c--magaz9e fire traps1 or film valves1 or fire valves ,d--upp] /eady-fe$ sprocket ,e--press] roll]s1 or friction roll]s1 or idl]s ,f--upp] fe$ loop or upp] loop ,g--film-/eady drum or film /eadi] ,h--film gate ,i--t5sion spr+ ,j--automatic fire %utt] ,k--revolv+ %utt] ,l--int]mitt5t sprocket ,m--l[] fe$ loop ,n--l[] /eady-fe$ sprocket ,o--take-up reel & l[] magaz9e ,p--fram+ device or adju/+ lev] 7n %[n7 ,q--film %ields ,illu/ration3 ,,figure #bh4 ,illu/ration3 ,,figure #bi4 ,9 addition to ! above1 !re are ! ge>+ & ! belt+ :i* transmit motion to ! v>i\s sprockets & drums %[n4 ,! :ole function ( ! ma*9e1 h[ev]1 is ! prop] mov+ ( ! film along ! l9es indicat$ 9 ! figure1 ! heavy black l9e repres5t+ ! film4 ,! film is unw\nd f ! upp] reel by ! upp] /eady fe$ sprocket ,d4 ,aft] =m+ ! upp] loop ,f1 x passes ov] ,g1 ?r\gh ! film gate ,h1 to ! int]mitt5t sprocket ,l4 ,?is sprocket moves ! film by an int]mitt5t motion all[+ ! film to rema9 /ation>y 9 ! light = ab\t f\r-eightie?s ( a second & %ift+ x dur+ ab\t "o-eightie? ( a second4 ,aft] leav+ ! int]mitt5t sprocket1 ! film =ms ! l[] loop & !n passes to ! l[] /eady fe$ sprocket1 :i* prev5ts ! take-up f pull+ ! loop away f ! int]mitt5t sprocket4 ,! object ( ! upp] & l[] loops is to light5 ! "w ( ! int]mitt5t sprocket z mu* z possible by mak+ x unnecess>y to move any?+ b ! film betwe5 ! two loops4 ,illu/ration3 ,,figure #cj4 ,all ( ! sprockets & ! %utt] ,k are connect$ toge!r by a tra9 ( ge>s 7see ,figure #cj1 :i* is ! ge>+ ( ! ,motiograph ma*9e7 & :5 prop]ly adju/$ !y all "w 9 prop] relation to ea* o!r4 ,! upp] /eady-fe$ sprocket fe$s j z mu* film into ! upp] loop z ! int]mitt5t sprocket takes away2 :ile ! l[] /eady-fe$ sprocket takes away j z mu* z ! int]mitt5t sprocket fe$s to x4 ,! film is unw\nd f ! upp] reel & rew\nd ^u ! l[]2 b be=e x is us$ aga91 x mu/ be rew\nd f ! l[] reel ^u ano!r "o4 ,if x 7 to be exhibit$ f ! l[] reel )\t ?is rew9d+1 ! pictures w\ld be exhibit$ backw>ds4 ,,discussion ,,( ,,p>ts4 ,a--,upp]1 or ,fe$ ,reel4--,! fe$ reel is usually ei!r #aj or #ab in*es 9 diamet]4 ,a #aj-;in* reel accommodates #a1jjj feet ( film & a #ab-;in* reel1 ab\t #b1jjj feet4 ,! reel fits loosely ^u be>+s 9 ! upp] magaz9e & ! film is unw\nd f ! reel1 :i* revolves1 by ! upp] /eady-fe$ sprocket4 ,to prev5t its unw9d+ m film ?an is want$1 a small spr+ is arrang$ to cause a slight friction4 ,x is be/ to keep good reels 9 ! op]at+ room = use z fe$ reels4 ,a reel to be us$ = ?is purpose %\ld be p]fectly true & 9 good ord]2 reels s5t out f ! ex*anges are (t5 b5t or h loose p>ts :i* cause tr\ble4 ,a good op]ator w keep a supply ( good reels always on h&4 ,b--,upp] ,magaz9e4--,! upp] magaz9e is a /eel box made up )\t sold] & fitt$ ) a /eel door on ! crank side ( ! ma*9e4 ,x exi/s = ! purpose ( protect+ ! film aga9/ fire or injury f o!r causes4 ,x is important t ! door be kept clos$ =1 )\t ?is precaution1 !re is no fire protection4 ,9 "s cities1 x is requir$ t ! door be provid$ ) spr+ h+es to keep x clos$1 b x is d\btful :e!r ?is is a wise provision2 = s9ce ! door mu/ be op5$ to *ange films & s9ce !re is ne>ly always great ha/e 9 mak+ ! *ange1 x is likely t ! op]ator w block ! door op5 if ! spr+ h+es int]f]e ) him4 ,all doors n[ sw+ to ! side1 b x seems z ?\gh x w\ld be a great improvem5t if ! doors 7 arrang$ to drop d[n4 ,! door w\ld !n1 ev5 if op51 prev5t fire f bel[ rea*+ ! film4 ,! magaz9e might z well be entirely miss+ z to be left ) ! side-sw++ door op54 ,_m op]ators h ! habit ( op5+ ! door to wat* ! progress ( ! reel in/ead ( not+ x on ! scre51 or ( prep>+ = a *ange ( reel by op5+ ! door long be=e necess>y & />t+ ! new run be=e clos+ ! doors4 ,ne$less to say1 ?is is highly repreh5sible4 ,9 ord] to put out a fire 9 case x %\ld communicate to ! reel1 ! magaz9es h be5 connect$ ) wat] pip+ & a valve s arrang$ t ! wat] c\ld be turn$ on in/antly ?us fill+ ! magaz9es4 ,if ! door ( ! magaz9e is kept clos$1 ! progress ( a fire w be comp>atively sl[4 ,c--,fire ,traps4--,! fire traps are an important adjunct4 ,_! object is to prev5t fire1 :i* (t5 occurs at ! ap]ture1 f rea*+ ! film on ! reel4 ,all ( ! v>i\s makes ( fire traps h be5 te/$ & w ord9>ily prev5t fire f pass+ ?r\gh !m4 ,! l>g] ! roll] & ! small] ! space ar\nd ! film1 ! bett] ! traps seem to be4 ,! metal ( ! roll]s has a cool+ effect ^u ! flame & ?is is und\bt$ly "o reason :y !y d _! "w s well4 ,none ( !m1 h[ev]1 is absolutely sure4 ,if ! op5+ ?r\gh :i* ! film passes is made too n>r[1 ! film is likely to bru% "o side or ! o!r & we> grooves 9 x1 or cut entirely ?r\gh x1 ) ! result t a splice may be caught 9 ! op5+ & ! film torn4 ,fire traps1 cut 9 ?is mann]1 h be5 ! cause ( _m fires4 ,?is tr\ble is due ma9ly to improp] alignm5t ( ! magaz9e ) ! fire traps4 ,exam9e !m (t5 &1 if ! lea/ we> %[s1 improve ! alignm5t4 ,x is advisable t e op]ator te/ 8 traps ) pieces ( film & assure himself t !y w n1 "u ord9>y circum/ances1 c>ry fire2 b he mu/ nev] rely too mu* ^u !m z safegu>ds1 = al?\gh !y w *eck a small blaze1 su* z w\ld result f ! burn+ ( a few in*es ( film1 !y w\ld probably n ext+ui% a fire occurr+ :5 !re 0 mu* film cr[d$ ar\nd !m1 z might be ! case :5 a take-up reel or ! int]mitt5t sprocket fail$ to "w4 ,if ! film cat*es fire & !re is any possible *ance to d s1 ! op]ator %\ld te> x (f at ! upp] & l[] magaz9es1 & ?us break ! communication4 ,b if !re happ5s to be a lot ( film ly+ loosely ab\t1 x is advisable = ! op]ator to get away z quick z possible4 ,d--,upp] ,/eady-,fe$ ,sprocket4--,! (fice ( ! upp] /eady-fe$ sprocket is to unw9d ! film f ! reel & fe$ x t[>d ! int]mitt5t sprocket4 ,9 ord] t x may d its "w well & relieve ! int]mitt5t sprocket ( all unnecess>y /ra91 !re mu/ be a loop ,f4 ,! upp] /eady-fe$ sprocket is 9 cont9ual /eady motion & fe$s j z mu* film to ! loop z ! int]mitt5t sprocket takes f x by p]iodical j]ks4 ,! ma9 tr\ble ) all sprockets is 9 ! we> ( ! tee?1 z 9 "t !y we> away ne> ! body ( ! sprocket & =m hooks4 ,! be/ sprockets h a numb] ( tee? to engage ! film4 ,9 "s ( ! old] ma*9es1 only two tee? cat* ! film1 9 :i* case1 if two holes 9 ! film are torn out1 ! film may /& /ill4 ,e--,press] or ,friction ,roll]s4--,! press] or friction roll]s exi/ m]ely to hold ! film 9 its prop] place4 ,!y are sometimes spok5 ( z friction roll]s al?\gh !y h no?+ to d ) friction4 ,f--,upp] ,loop4--,! upp] loop is provid$ = ! purpose ( /or+ slack film :i* ! int]mitt5t sprocket may pull away ) a v rapid j]k4 ,x avoids plac+ unnecess>y /ra9 ^u ! film4 ,! upp] loop (t5 causes tr\ble by enl>g+2 ?is occurs :5 ! int]mitt5t sprocket fails to "w :ile ! /eady sprocket cont9ues to fe$4 ,! mo/ frequ5t cause ( ?is is due to faulty films4 ,9 ord] to prev5t ! excess film 9 ! upp] loop f fall+ ov] 9 front ( ! light ( ! arc lamp 7:i* w\ld quickly set x on fire71 ! film %ields ,q are provid$4 ,9 _m ma*9es !y are too %ort or too n>r[ to be ( mu* use4 ,g--,film-,/eady ,drum1 or ,film ,/eadi]4--,! film /eadi] is n f\nd 9 all ma*9es4 ,if ! upp] portion ( ! ma*9e head is prop]ly arrang$1 ! film may fe$ directly into ! gate4 ,h--,film ,gate4--,! film gate is to hold ! film 9 position4 ,9 ord] t ! picture may be prop]ly project$1 ! film mu/ lie p]fectly flat & at a fix$ di/ance f ! l5ses4 ,if ?is di/ance v>ies1 !re w be improp] focus+ ( ! picture4 ,! film mu/ also be held 9 its prop] position lat]ally & v]tically4 ,! film gate has no?+ to d ) ! height ( ! film4 ,?is is tak5 c>e ( by ! fram+ device4 ,! film gate we>s q rapidly & :5 badly worn all[s ! film too mu* play4 ,9 ord] to avoid ! wobbl+ ( ! picture1 a new gate mu/ be provid$4 ,!re %\ld be consid]able metal surr\nd+ ! ap]ture & !re %\ld also be an air space & "s little v5tilation4 ,! metal surr\nd+ ! gate is subject to ! heat f ! arc lamp rays &1 unless prop]ly con/ruct$1 may ov]heat & damage ! t5sion spr+s1 if x does n set fire to ! film4 ,i--,t5sion ,spr+s4--,! t5sion spr+s are provid$ to hold ! film flat aga9/ ! film gate & also to *eck its motion z soon z ! int]mitt5t sprocket has /opp$ pull+ x4 ,a c]ta9 int]mitt5t movem5t is adv]tis$ to make ! *ange f "o picture to ano!r 9 #a_/if ( a second at normal op]at+ spe$4 ,! film mov$ at ?is rate ( spe$ acquires consid]able mom5tum2 & ! (fice ( ! t5sion spr+ is to br+ x to re/ z quickly z possible4 ,if ! spr+s are set too tight1 !y w cause ! ma*9e to run h>d & may also be ! cause ( te>+ out splices4 ,!y %\ld be set j tight en\gh to keep ! picture /eady2 any?+ beyond ?is w m]ely cause unnecess>y we> ( ! p>ts1 besides call+ = unnecess>y ex]tions on ! "p ( ! op]ator4 ,j--,automatic ,fire ,%utt]4--,! automatic fire %utt] is provid$ = ! purpose ( %utt+ (f ! light :5 ! ma*9e is n 9 motion4 ,x is requir$ by mo/ city ord9ances4 ,! ideal fire %utt] w\ld be "o s controll$ by ! film t x w\ld rema9 up only :ile ! film is mov+ at op]at+ spe$4 ,! %utt]s 9 use at ! pres5t "t v>y widely 9 details ( con/ruction4 ,"s ( !m are rais$ & admit ! light to ! film ! in/ant ! h&le is press$ suffici5tly to />t ! ma*9e4 ,o!r types are rais$ only aft] ! ma*9e has ne>ly atta9$ its prop] spe$4 ,"s op]ate z indicat$ 9 ! figure & o!rs op]ate f ! side4 ,all ( !m are liable to become d]ang$ at times1 & x is no unusual ?+ to f9d !m ti$ up 9 "s way because !y fail$ to "w prop]ly4 ,! %utt] is a great conv5i5ce :5 9 prop] ord] & has probably prev5t$ _m fires2 b x is good practice to consid] x z entirely abs5t & n get into ! habit ( rely+ ^u x4 ,! op]ator %\ld always pu% 8 lamp to ! side :5ev] any?+ is out ( ord]4 ,?is act is necess>y 9 mo/ h\ses at ! end ( e run ( film %[+ /]eopticon slides4 ,x w\ld inconv5i5ce ! op]ator b little to d ?is at all times1 & !n ! habit w\ld be =m$ & become second nature4 ,on ! ma*9es n[ 9 use1 !re is no automatic %utt] gov]n$ by ! action ( ! film1 :i* w\ld give protection 9 case ! film %\ld come to re/1 z old films (t5 d :5 _! sprocket holes are torn out1 or1 z (t5 happ5s1 :5 ! film splits along ! r[ ( holes4 ,9 "s ma*9es ! fire %utt] is made up ( su* ?9 mat]ial & re/s s close to ! film t ! light may heat x suffici5tly to fire ! film bel[ x4 ,pieces ( film (t5 become deta*$ at ! ap]ture & rema9 9 ! light long en\gh to be ignit$4 ,aga9/ su* occurr5ces z ^! !re is no protection :atev] except ! wat*fulness ( ! op]ator4 ,if ! film fits snugly into ! gate & is well enclos$1 su* fires d n usually spread4 ,k--,! ,revolv+ ,%utt]4--,! revolv+ %utt] is sometimes arrang$ 9 front ( ! ma*9e & (t5 betwe5 ! film & ! l5ses4 ,! %utt] ,k is ( ! 8b>rel0 type & is fur!r illu/rat$ 9 ,figure #ca at ! left4 ,! object ( ! %utt] is to %ut (f ! light dur+ ! "t t ! film is 9 motion s t ! impressions made ^u ! eye by ! succession ( /ation>y pictures may n be blurr$ by ! motion ( ! film :5 x is *ang$4 ,! ideal %utt] is "o t %uts ! light (f in/antly &1 at ! expiration ( ! necess>y "t1 all[s x z quickly to come to view aga94 ,! b>rel-type %utt] all[s ! light to pass ?r\gh :ile x is 9 ! position %[n by solid l9es1 ,figure #ca1 & has x entirely %ut (f :5 9 ! position indicat$ by brok5 l9es4 ,:5 x is 9 motion1 ! upp] w+ beg9s to %ut (f ! light f ! top & ! l[] f ! bottom1 ?us caus+ ! total eclipse ( light 9 "o-half ( ! "t t a s+le w+ %utt] c\ld d x4 ,illu/ration3 ,,figure #ca4 ,at ! "r ( ,figure #ca1 we h a cone %utt] su* z is us$ 9 ! ,motiograph4 ,! /em & ge>+ ( ?is %utt] are set at an angle ( =ty-five degrees to ! rays ( light1 = ! purpose ( arrang+ !m inside ( ! me*anism )\t tak+ up too mu* room4 ,!re are two cones ( ! k9d illu/rat$ 9 ,figures #cb & #cc & !y move 9 opposite directions1 ?us %utt+ (f ! light 9 ab\t ! same "t t a b>rel %utt] c\ld be made to d x4 ,^! two figures %[ ! positions ( w+s j be=e %utt+ (f ! la/ ve/ige ( light & j z !y are beg9n+ to admit x aga94 ,illu/ration3 ,,figure #cb4 ,illu/ration3 ,,figure #cc4 ,! disk type ( %utt] is mu* us$4 ,x may h ei!r "o1 two1 or ?ree blades & may also be d\ble1 i4e41 two disks revolv+ 9 opposite directions s z to %ut (f ! light f two sides ( ! op5+ at once4 ,?ree types ( disk %utt]s are %[n 9 ,figures #cd to #cf4 ,9 ord] to obta9 a flick]less picture1 x is necess>y to cut (f ! light n only dur+ ! "t t ! film is 9 motion1 b also dur+ "p ( ! "t t x is /&+ /ill4 ,if ! light 7 n int]rupt$ dur+ ! "t ( exposure1 ! light int]val w\ld be s long t ! diff]5ce betwe5 ! d>k p]iod1 :5 x is %ut (f entirely1 & ! light p]iod w\ld be great en\gh to be notic$ 9 ! =m ( a flick]4 ,illu/ration3 ,,figure #cd4 ,illu/ration3 ,,figure #ce4 ,illu/ration3 ,,figure #cf4 ,if a s+le-blade %utt] is us$1 x mu/ make two revolutions dur+ ! "t t a s+le picture is expos$2 once to %ut (f ! light :ile ! film is be+ mov$ & once to int]rupt ! p]iod ( illum9ation4 ,?is %utt] w\ld ?us h to run twice z fa/ z ! two- or ?ree-blade %utt]1 ! ?ree-blade %utt] int]rupt+ ! light twice dur+ ! "t ! film is /&+ /ill4 ,! ?ree-blade %utt] has "o wide blade :i* mu/ be 9 front ( ! light :ile ! film is mov+ & two n>r[] ones :i* int]rupt ! light dur+ ! "t ( exposure4 ,! two-blade %utt] mu/ h bo? blades ( ! same size & run "o & "o-half times z fa/ z ! ?ree-blade %utt] to obta9 ! same effect1 i4e41 cause two int]ruptions ( light dur+ ! "t ( exposure4 ,9 ord] to %ut ! light (f v rapidly ) a blade1 :i* approa*es ! op5+ f "o side only1 ! disk %utt] mu/ be ( suffici5t size to produce great angul> velocity4 ,x c n well be us$1 !re=e1 inside ( ! me*anism1 b is usually plac$ 9 front ( ! ma*9e2 & x is mu* l>g] ?an ! ap]ture :i* x mu/ cov]4 ,! %utt]s mu/ all be set s z to %ut (f ! light dur+ ! "t t ! film is 9 motion4 ,:5 ! divid+ l9e betwe5 two film pictures is 9 ! c5t] ( ! ap]ture1 ! %utt] %\ld h x entirely cov]$4 ,x is possible1 h[ev]1 to arrange ! %utt] s t ! film may move a trifle be=e ! light is %ut (f & cont9ue 9 motion also = a v %ort "t aft] ! light is aga9 admitt$4 ,?is is practicable ) ! 8,g5eva0 int]mitt5t movem5t :i* />ts & /ops ! film gradually4 ,a %utt] %\ld be adapt$ to ! spe$ ( ! film movem5t4 ,!re is no ne$ ( keep+ ! film cov]$ any long] ?an x is 9 motion4 ,a quick film movem5t & a n>r[ %utt] w add consid]ably to ! light obta9$ f a giv5 lamp & a giv5 curr5t consumption4 ,if ! %utt] is n prop]ly adju/$1 !re w be :at is kn[n z 8travel gho/01 8light ra901 or 8halo04 ,^! are due to ! improp] tim+ ( ! %utt]1 all[+ a "p ( ! picture to be se5 :ile 9 motion4 ,! travel gho/ may be se5 ei!r at ! top or ! bottom1 accord+ to :e!r ! %utt] is set too fa/ or too sl[4 ,illu/ration3 ,,figure #cg4 ,illu/ration3 ,,figure #ch4 ,l--,int]mitt5t ,sprocket4--,! int]mitt5t sprocket is a v important "p ( ! ma*9e4 ,ow+ to ! swiftness ) :i* x /rikes ! film1 ! tee? on x are m subject to we> ?an ^? on ! o!r sprockets4 ,! numb] ( tee? t engage ! film is also an important item4 ,9 ord] to obta9 ! be/ picture ) ! lea/ exp5diture ( light1 ! film %\ld be mov$ v rapidly s z to all[ ! greate/ possible l5g? ( "t = ! /ation>y picture4 ,! film %\ld1 fur!rmore1 be />t$ sl[ly2 !n increas$ 9 spe$2 & ! spe$ %\ld decrease gradually until br\ght to re/1 & ?us avoid unnecess>y j]k+4 ,x is also necess>y to prev5t all motion ( ! film dur+ ! "t ! me*anism :i* moves x is prep>+ = ! next succe$+ movem5t4 ,all ( ^! conditions are admirably fulfill$ by ! 8,g5eva0 movem5t1 ,figure #cg4 ,! p9 :eel ,w is 9 cont9u\s motion & ! p9 is s plac$ ^u x t x ent]s "o slot ( ! cross & c>ries x along ) x1 ?us caus+ a qu>t] revolution ( ! cross ea* "t ! p9 :eel makes "o revolution4 ,! cam b& ,p is cut away suffici5tly to all[ ! cross to make a qu>t] revolution1 b ! rema9+ portion ( x is made to fit ! cross snugly1 s t :5 ! cross is n 9 motion x is held rigid4 ,figure #cg %[s ! movem5t j />t+ & ,figure #ch %[s x half complet$4 ,x c be se5 t ! motion beg9s v sl[ly2 comes to a maximum :5 x is 9 ! middle2 & ends sl[ly2 ?us subject+ ! film to ! lea/ possible /ra94 ,?is movem5t is widely us$ & may be arrang$ ) "o p91 z %[n1 or ) two4 ,if ! p9 :eel is equipp$ ) two p9s1 x w move only half z fa/ z ) "o p9 & ?us ! proportionate "t t ! film is 9 motion w be l5g!n$4 ,by mak+ ! p9 :eel l>ge z comp>$ ) ! cross or />1 ! "t dur+ :i* ! motion takes place c be r$uc$ z mu* z desir$2 b ! *>act]i/ic feature ( />t+ & /opp+ ! film gradually w be lo/ directly 9 proportion z ! relative size ( ! p9 :eel is increas$4 ,illu/ration3 ,,figure #ci4 ,! 8,g5eva0 movem5t requires extremely accurate con/ruction & c>eful managem5t4 ,if du/y or insuffici5tly lubricat$1 x we>s v rapidly4 ,x is (t5 arrang$ s t x c be imm]s$ 9 oil :ile runn+4 ,figure #ci %[s a practical application ( ! 8,g5eva0 z us$ 9 ! ,motiograph4 ,! cov] %[n at ! "r entirely encloses x4 ,illu/ration3 ,,figure #dj4 ,illu/ration3 ,,figure #da4 ,illu/ration3 ,,figure #db4 ,illu/ration3 ,,figure #dc4 ,a =m ( int]mitt5t movem5t :i* has lately come out & is us$ on ! ,p[]s ,no4 #f ,cam]agraph is %[n 9 ,figures #dj to #db inclusive4 ,! mov+ elem5t ( ?is int]mitt5t movem5t is a diamond-%ap$ projection on ! surface ( a revolv+ disk4 ,! driv5 elem5t is a cross c>ry+ f\r p9s--t]m$ a 8p9 cross0--& is indicat$ by brok5 l9es4 ,! rais$ portion ,a ( ! diamond /rikes "o ( ! p9s ( ! cross & />ts x 9 motion z indicat$ 9 ,figure #da4 ,! movem5t ( ! cross c be trac$ by ! black dot indicat+ "o ( ! p9s4 ,at e revolution ( ! driv+ disk1 ! cross makes "o qu>t] ( a revolution & :5 n 9 motion is held rigidly lock$ by ! lock+ r+ ,r1 :i* fits snugly betwe5 ! p9s4 ,?is movem5t probably moves ! film 9 ! %orte/ "t ( any4 ,x is entirely encas$1 runs 9 oil1 & is practically noiseless4 ,! mann] 9 :i* x is in/all$ 9 ! ma*9e is indicat$ 9 ,figure #dc4 ,m--,l[] ,fe$ ,loop4--,! l[] fe$ loop is provid$ to prev5t ! l[] sprocket f pull+ on ! film & ?us int]f]+ ) ! "w ( ! int]mitt5t sprocket4 ,! int]mitt5t sprocket fe$s ! loop1 by j]ks1 ?ree-f\r?s ( an in* ( ! film at a "t2 & ! l[] sprocket is ge>$ to take away t mu* by /eady motion4 ,?us1 ev]y?+ work+ prop]ly1 ! loop rema9s ( ! same size4 ,9 case ! l[] sprocket is n work+ prop]ly1 ! loop may become enl>g$ & ! film may run onto ! floor4 ,sometimes ! int]mitt5t sprocket does n "w prop]ly & ! l[] sprocket pulls away all ( ! loop4 ,n--,l[] ,/eady-,fe$ ,sprocket4--,! l[] /eady-fe$ sprocket ma9ta9s ! loop & re/ra9s ! film4 ,if x 7 n = ?is sprocket1 ! take-up me*anism w\ld pull directly on ! int]mitt5t sprocket & keep ! film jiggl+4 ,illu/ration3 ,,figure #dd4 ,o--,take-up ,reel4--,! take-up reel is id5tical ) ! upp] reel &1 9 fact1 ! two are g5]ally us$ int]*angeably4 ,9 bo? cases1 only p]fect reels %\ld be us$2 & reels deliv]$ by ex*anges are v (t5 untru/wor?y4 ,! pr9ciple ( ! take-up me*anism is %[n 9 ,figure #dd4 ,:5 a run ( film is />t$1 ! diamet] ( ! roll ( film be+ small1 ! reel mu/ travel comp>atively fa/ to take up ! film z fa/ z x is unw\nd f ! upp] reel4 ,z m & m film is ga!r$ by ! l[] reel1 ! travel mu/ become sl[] until f9ally1 ) a twelve-in* reel1 ! numb] ( revolutions p] m9ute are b ab\t "o-f\r? z _m z at ! beg9n+4 ,9 ,figure #dd1 ,a is ! reel :i* is fa/5$ to ! sp9dle ,b2 ,c is a coll> also fa/5$ to ! same sp9dle4 ,d is a loose pulley capable ( revolv+ ar\nd ! sp9dle )\t imp>t+ motion to x & arrang$ s t x c be driv5 by a belt4 ,e is a spiral spr+ :i* is controll$ by ! small coll> ,f1 & x presses ! loose pulley aga9/ ! coll> ,c4 ,if ! loose pulley is press$ aga9/ ,c ) suffici5t =ce1 x w cause ,c to revolve ) x2 & ! movem5t ( ,c w imp>t motion to ! reel & w9d up ! film :i* is fa/5$ to x4 ,d mu/ revolve fa/ en\gh s t1 ev5 :5 ! reel is empty1 x w take up all ( ! film f$ to x4 ,z ! film is w\nd up1 ! size ( ! roll ( film increases & ! spe$ mu/ become less2 ?us ,d beg9s to slip a little on ,c & ?is slippage increases until ! end ( ! run4 ,friction 9 "o =m or ano!r is ! only me?od by :i* take-up reels are n[ op]at$2 b 9 "s ( !m ?is friction may be 9 a belt1 z well z 9 ! two disks z %[n4 ,sometimes a fib] wa%] is int]pos$ betwe5 ! two friction disks4 ,9 ! ,motiograph take-up1 ,figure #de1 ! necess>y friction & slip are all 9 ! belt+4 ,illu/ration3 ,,figure #de4 ,if ! take-up is n h&l+ ! film prop]ly1 x is due to a loose belt or to insuffici5t t5sion on ! spr+4 ,! take-up probably causes m tr\ble ?an any o!r "p ( ! me*anism & x %\ld be c>efully wat*$4 ,on acc\nt ( ! tr\ble incurr$ f x1 !re are /ill _m op]ators :o pref] to run films into a tank2 al?\gh ! take-up saves !m mu* "t4 ,a c>eful op]ator :o und]/&s ! c>e ( ma*9]y w\ld h little tr\ble ) a take-up2 :ile ! "o :o has n ! faculty ( keep+ ?+s 9 ord] w\ld1 p]haps1 be bett] (f 7fire haz>d neglect$7 ) a tank4 ,) mo/ ma*9es1 ! take-up magaz9e is locat$ :]e x is v difficult = ! op]ator to wat* its op]ation4 ,^? ma*9es 9 :i* x is locat$ 9 easy sight ( ! op]ator h consid]able advantage 9 ?is respect4 ,a c>eless op]ator is (t5 compell$ to op5 ! l[] magaz9e door & turn ! reel by h& :5 ! take-up t5sion is out ( ord]4 ,rememb] t ! take-up c cause tr\ble only :5 x is out ( ord] & t a good op]ator w nev] all[ x to get out ( ord] & he w inspect x c>efully be=e e %[4 ,p--,fram+ ,device4--,! ap]ture 9 ! film gate is j l>ge en\gh to fit ! picture on ! film4 ,if ! film is accurately plac$1 ! :ole picture w %[ ^u ! scre54 ,9 ord] to br+ ?is ab\t1 ! ma*9e mu/ ei!r be provid$ ) a means ( adju/m5t1 or a c]ta9 "p ( ! film mu/ be plac$ ^u a c]ta9 sprocket too?4 ,?is latt] me?od causes consid]able annoyance & wa/e ( "t2 fur!rmore1 e splice 9 a film w\ld h to be made exactly "r or ! :ole succe$+ "p ( ! %[ w\ld be 8out ( frame04 ,9 ord] to avoid ^! tr\bles1 e ma*9e is provid$ ) a s-call$ fram+ device4 ,some:]e ab\t ! ma*9e1 conv5i5t to ! op]ator1 w be f\nd a lev] by :i*1 dur+ ! op]ation ( ! ma*9e & )\t int]ruption1 ! position ( ! film ) ref]5ce to ! film w9d[ & ! l5s may be adju/$ ei!r up or d[n4 ,! precise mann] 9 :i* ?is is done v>ies ) diff]5t ma*9es4 ,! fram+ device mu/ be capable ( adju/+ ! film to some:at m ?an ! wid? ( "o picture4 ,! splice %\ld be s made t fram+ becomes unnecess>y & ?is is accompli%$ by cutt+ out full pictures s z to leave ea* picture ) ! full f\r holes4 ,if a picture is left1 = in/ance1 ) only two holes1 x w appe> ^u ! scre5 ) ! black l9e1 :i* %\ld be hidd5 9 ! c5t]4 ,if ?is happ5s1 by mov+ ! fram+ lev] ei!r up or d[n1 ! picture c aga9 be c5t]$ ^u ! scre54 ,illu/ration3 ,,figure #df4 ,q--,film ,%ields4--,! film %ield is an important "p ( ! ma*9e2 al?\gh x is (t5 v mu* neglect$ & 9 _m ma*9es is s small z to be practically useless4 ,x %\ld prev5t films f cr[d+ out into ! light :5 ! loops enl>ge4 ,_m op]ators d n take k9dly to ma*9es t enclose ! film too tightly2 = 9 case ! take-up fails to "w prop]ly1 x is (t5 a conv5i5ce to be able to h&le ! film4 ,?is is also ! case :]e v badly torn or old film is us$4 ,_m old films are s badly worn t !y w n run prop]ly on ! sprockets & mu/ be v closely wat*$4 ,illu/ration3 ,,figure #dg4 ,illu/ration3 ,,figure #dh4 ,x is n ?\ght necess>y or advisable to g into ! details ( con/ruction ( any p>ticul> ma*9e z *anges are made ne>ly e ye> s t su* description w\ld n be ( great value & might1 9 fact1 be mislead+4 ,any p]son possess+ a little me*anical +5uity & tak+ an int]e/ 9 su* matt]s c readily le>n ! peculi>ities ( any ( ! ma*9es4 ,!y are1 aft] all1 :5 "o has ma/]$ ! pr9ciples1 q simple affairs4 ,all progressive manufactur]s1 fur!rmore1 publi% in/ruction books :i* are issu$ :5ev] a *ange is made 9 any ma*9e2 & ^! are always obta9able4 ,illu/ration3 ,,figure #di4 ,9 ,figure #df we h a g5]al view ( ! ,ed5graph ma*9e4 ,x w be notic$ t ! total l5g? ( film betwe5 ! two magaz9es is expos$ to view mak+ ?read+ ( ! film v easy2 also t ! revolv+ %utt] works betwe5 ! objective l5s & ! film gate4 ,! well-kn[n ,edison ma*9e is %[n 9 ,figure #dg4 ,?is is "o ( ! be/ kn[n ma*9es2 & x is v compact & durable4 ,illu/ration3 ,,figure #ej4 ,! ,motiograph is %[n 9 ,figure #dh4 ,! take-up1 %[n on ! l[] magaz9e1 is diff]5t 9 ?is ma*9e f :at x is 9 ! o!rs4 ,?is ma*9e also has a special rew9d feature4 ,by an adju/m5t ( ! op]at+ h&le1 ! film1 aft] hav+ be5 run (f onto ! take-up reel1 c be rew\nd ^u ! upp] reel )\t tak+ x out ( ! magaz9es4 ,figure #di %[s a g5]al view ( ! ,p[]s ,no4 #f ,cam]agraph me*anism4 ,! ,simplex me*anism is %[n 9 ,figure #ej4 ,9 ?is ma*9e ! film is entirely enclos$ betwe5 ! two magaz9es4 ,,*apt] ,,vi4 ,,! ,,film4 ,film ,mak+ & ,*>act]i/ics4--,all film is ( celluloid4 ,! comm]cial film us$ = ! projection ( motion pictures comes 9 long /rips1 is ab\t "o & ?ree-eigh?s in*es wide1 & ab\t "o two-hundr$?s ( an in* ?ick4 ,^u "o side ( ?is film is a photographic emulsion ( gelat9e impregnat$ ) a solution ( bromide ( silv]4 ,?is silv] is s5sitive to ! light & has ! prop]ty ( turn+ black1 dur+ ! process ( develop+1 9 proportion to ! quantity ( light t has /ruck ! diff]5t p>ts ( ! emulsion4 ,:]ev] ! light has be5 v int5se or has be5 appli$ = a suffici5tly long "t1 ! film1 aft] treatm5t ) a prop] develop+ fluid1 becomes v black2 :]e no light has rea*$ x1 x rema9s :ite2 & 9 ! int]m$iate portions1 ! %ad+ is 9 proportion to ! light t has rea*$ ^? p>ts4 ,film t has n be5 expos$ & develop$ is ( a creamy yell[i% color &1 if imm]s$ 9 a solution ( hyposulphite ( soda1 w turn p]fectly cle> & (f] no ob/ruction to ! light4 ,if1 on ! o!r h&1 x is completely expos$ & develop$1 x w become solid black2 su* black pieces are sometimes us$ z lead]s & tails 9 connection ) motion pictures4 ,! emulsion on ! film melts at a temp]ature ( ab\t #ij degrees ,fahr5heit & w !n run (f ! film4 ,x is also soluble 9 w>m wat]4 ,! celluloid ( ! film is v inflammable & bur/s into flame at a temp]ature ( #bhd degrees ,fahr5heit4 ,if x is ignit$ :ile tightly w\nd ^u a reel1 x burns some:at sl[ly2 if x is ignit$ 9 a tank1 ! beg9n+ ( ! fire is also sl[2 b z soon z ! air 9 ! tank atta9s ! prop] temp]ature1 ! :ole ( ! film bur/s into flame at once4 ,x acts 9 ?is respect v mu* l gunp[d]4 ,9 burn+1 ! film gives (f a d5se br[ni% mass ( poison\s smoke4 ,film w burn ev5 :5 x has no access to ! air & a film fire _c be put out by smo!r+4 ,be=e s5d+ out _! films1 ! manufactur]s treat !m ) glyc]9e4 ,?is is = ! purpose ( keep+ !m pliable z long z possible4 ,9 "t1 h[ev]1 a film dries out & !re is !n v little t c be done ) x4 ,at any rate1 :atev] is to be done %\ld be done by ! ex*ange1 z no op]ator has facilities = h&l+ x4 ,"s films are wat]pro($ & a little wat] w n damage !m mu*2 b o!r films mu/ be kept dry4 ,if by accid5t a roll ( film %\ld become wet1 x c be sav$ by v quickly unroll+ x & spread+ x out to dry4 ,if x c be spread out quickly en\gh1 x w n be h>m$2 b if x is n spread out at once1 ! emulsion w /ick to ! celluloid & w come (f :5 ! film is f9ally unw\nd4 ,!re is also a process ( firepro(+ film4 ,?is mu/ n1 h[ev]1 be too ?or\ghly reli$ ^u1 especially if ! film is old4 ,firepro( film is a valuable aid1 b x is be/ to treat x exactly l o!r film 9 respect to ! fire haz>d4 ,on acc\nt ( its inflammable "*1 film %\ld always be kept 9 firepro( enclosures4 ,! film conta9s sixte5 pictures to ea* foot & = e picture !re are f\r sprocket holes on ea* side ( ! film4 ,! size ( ! ap]ture plate & also ! size ( ! actual picture on ! film is #aa_/af in* high by #ae_/af in* wide4 ,if ! picture on ! scre5 is enl>g$ to #ah feet #i in*es 9 wid? & #ac feet #i in*es high1 e "p ( ! picture on ! film w appe> #eg1fjj times z l>ge on ! scre5 z x is 9 ! film4 ,9 view+ a #ajjj-;foot film1 ! audi5ce w see #af1jjj sep>ate pictures foll[+ ea* o!r s rapidly t ! *ange f "o to ! o!r w be unnoticeable4 ,if a ?ree-blade %utt] is us$1 ! behold] w see ! light %ut (f & turn$ on #dh1jjj times 9 ! same run ( film1 b w n be able to notice x if ! spe$ ) :i* x is done is correct4 ,new film com+ directly f ! ex*ange is likely to be too moi/ & cause tr\ble f t condition2 :ile old film is likely to be too dry & cause tr\ble by w>p+ or b5d+ out ( %ape4 ,pat*+ ,film4--,all reels ( films conta9 pat*es & b little tr\ble w arise f !m1 provid$ !y are prop]ly made & reasonable c>e is ex]cis$ 9 wat*+ !m4 ,9 ord] to obta9 a satisfactory splice1 x %\ld n be made m ?an #c_/af in* long2 a great] l5g? ?an ?is w rea* two sprocket tee? & ?is is objectionable because ! splice /iff5s ! film & w prev5t x f fitt+ ! tee? prop]ly4 ,! splice %\ld be s made t x does n ?r[ ! pictures out ( frame4 ,if made prop]ly1 x w nev] be notic$ 9 ! runn+ picture at all1 unless a l>ge quantity ( film is cut out4 ,if h[ev]1 ! splice be made ov] "p ( a picture--z w\ld be ! case if an improp] numb] ( holes 7 cut out--! picture1 :5 project$1 w\ld appe> out ( frame1 i4e41 ! divid+ l9e betwe5 two pictures w\ld !n appe> on ! scre5 & w\ld cont9ue to %[ until ! fram+ lev] _h be5 adju/$ to cov] ! divid+ l9es aga94 ,c>e mu/ also be tak5 t ! film is /raight aft] be+ splic$4 ,if ! ends are n fitt$ squ>ely to ea* o!r1 !re w be a b5d 9 ! film at ! po9t ! splice is made2 & ?is may cause tr\ble4 ,_m op]ators h a plate ( gr\nd glass fitt$ into a "w b5* at ! place :]e splices are to be made & a small lamp "u ?is glass4 ,?is is v conv5i5t =1 z a rule1 ! illum9ation 9 an op]at+ room is v poor al?\gh a good light is necess>y to mat* film prop]ly4 ,if gr\nd glass is us$1 ! r\gh side mu/ be at ! bottom2 o!rwise x w be difficult to clean (f ! cem5t :i* adh]es to ! glass4 ,by mak+ e splice 9 exactly ! same ord]1 ! op]ator w acquire ! habit ( do+ x nicely & quickly4 ,mo/ splices are made 9 a hurry 7be=e or aft] a %[7 & 9 ?is1 z well z 9 all ?+s t mu/ be done ha/ily & at a mom5t's notice1 habit & practice are v important4 ,"o does n become exp]t until he has practic$ x (t5 en\gh to be able to d x me*anically4 ,illu/ration3 ,,figure #ea4 ,proce$ z foll[s & z outl9$ 9 ,figure #ea3 ,cut exactly along ! divid+ l9e ( "o picture & save ?is to become ! top piece4 7,! emulsion side ( ! two sections ( film mu/ always be ei!r up or d[n1 & = conv5i5ce x is well to =m ! habit ( hav+ !m always "o way or ! o!r47 ,n[1 ) a %>p knife1 scrape ! celluloid side ( ?is piece until all ( ! gloss is remov$ = a wid? ( a little m ?an #c_/af in*4 ,d n scrape any m ?an necess>y1 b be sure t all dirt & oil are remov$4 ,n[ take up ! o!r "p ( ! film & cut (f ! bad portion1 leav+ a /rip a trifle less ?an #c_/af in* beyond ! divid+ l9e4 ,?is /rip ne$ n be scrap$ on ! back1 b all ( ! emulsion mu/ be scrap$ f ! front side ( x4 ,to scrape ! front side nicely1 lay a %ort rul] across x to act z a guide = ! knife & scrape up to ?is rul]4 ,scrape only to ! divid+ l9e1 b give p>ticul> att5tion to ! sprocket holes & ! edges1 = x is at ! edges & sprocket holes t film fir/ beg9s to "w loose & :]e x is mo/ difficult to secure prop] adhesion4 ,bo? p>ts ( ! film %\ld be s scrap$ t1 :5 f9i%$1 ea* w furni% half ( ! divid+ l9e4 ,n[ apply a lib]al coat+ ( cem5t to ! latt] section & c>efully lay ! fir/ ^u x1 tak+ great c>e t ! sprocket holes 9 ! two sections ov]lap & mat* p]fectly4 ,x is = ?is mat*+ purpose t ! glass 9 ! table 7) a small lamp und]nea? x7 is valuable4 ,! sprocket holes mu/ mat* accurately & ! films mu/ l9e up /raight4 ,aft] ! upp] film is plac$1 x mu/ be press$ d[n = a few seconds until ! cem5t has set4 ,wipe (f all sup]flu\s cem5t be=e x has "t to set4 ,be sure t !re are f\r sprocket holes = ea* picture4 ,keep a knife on h& & use x = no o!r purpose4 ,keep also a suitable /one on :i* to %>p5 ?is knife1 =1 unless ! knife is v %>p1 x w d only poor "w & ! edge on x w n la/ long at any rate4 ,ord9>y cem5t w n hold non-inflammable film1 & wat]-pro( film mu/ be m ?or\ghly scrap$ ?an ord9>y film4 ,9 ! b5*1 provide a recess into :i* ! cem5t vessel may be set & :]e x w always rema94 ,provide also a pair ( scissors = cutt+ ! film4 ,illu/ration3 ,,figure #eb4 ,! ,edison film m5d] is %[n 9 ,figure #eb4 ,?is is made ) ?ree gates or h+es4 ,^? on ! "r & left clamp d[n to hold ! film1 :ile ! n>r[] "o 9 ! c5t] clamps d[n on ! cem5t$ edge4 ,to m5d a film1 place "o ( ! pieces to be jo9$ 9 ! m5d]4 ,place t "p ( ! gage m>k$ 8cut0 9 position1 cutt+ betwe5 fir/ & second p]=ations above ! floor l9e sep>at+ ! picture4 ,! rema9+ piece ( film %\ld be plac$ 9 ! o!r side ( ! m5d] & cut exactly on ! l9e4 ,set ! opposite end ( ! gage m>k$ 8scrape0 on ! fir/ section2 remove ! emulsion2 cut to ! floor l9e ) a %>p p5 knife1 moi/5+ x s t ! emulsion w come (f easily4 ,aft] apply+ ! cem5t ) a bru% to ! scrap$ piece1 lay ! o!r piece ov] x 9 ! m5d]1 clamp+ x d[n2 & leave x = an in/ant to adh]e4 ,,*apt] ,,vii4 ,,g5]al ,,h9ts ,,on ,,in/allation1 ,,op]ation1 ,,& ,,c>e ,,( ,,ma*9es4 ,tools4--,fir/ ( all provide a suitable & suffici5t set ( tools4 ,!re %\ld be an assortm5t ( screw driv]s1 l>ge & small1 to fit ! diff]5t sizes ( screws us$ n only ) ! ma*9e b ab\t ! op]at+ room & ) o!r devices z well4 ,keep ^! screw driv]s fil$ or gr\nd to prop] %apes4 ,a screw driv] r\nd$ (f1 or too small1 or b5t1 w ru9 ! heads ( ! screws4 ,!re %\ld also be a collection ( pli]s 7especially su* z are commonly t]m$ 8gas pli]s071 files1 raps1 *isels 7= wood & metal71 pun*]s1 drills1 & monkey wr5*es2 a hack saw1 a bl[ tor*1 & a vise w also come 9 h&y4 ,tools1 h[ev]1 dep5d ^u ! man :o uses !m4 ,!re are m5 :o w\ld be no bett] (f ) su* a collection at _! disposal2 on ! o!r h&1 a clev] man w\ld be able to make use ( all ^! tools & %[ 8 skill !reby4 ,align+ ! ,ma*9e4--,! fir/ ?+ to d 9 sett+ up a new ma*9e1 aft] x has be5 unpack$ & put toge!r1 is to l9e x up prop]ly4 ,?is c be done by /ret*+ a /r+ f ! lamp h\se1 ?r\gh ! c5t] ( ! cond5s] op5+1 film gate1 & objective l5ses4 ,^! mu/ all be 9 su* a position relative to "o ano!r t a taut /r+ w pass ?r\gh ! c5t] ( ea*4 ,! c5t] c be det]m9$ by measurem5t ei!r ) a suitable rule or a pair ( calip]s4 ,an*or+ ! ,ma*9e4--,! next /ep is to an*or ! ma*9e s z to r$uce vibration to a m9imum4 ,vibration is (t5 due to a flimsy floor :i* w n /& ! /ra9 ( ! unavoidable vibration & ?us helps to increase x4 ,(t51 h[ev]1 ! vibration is due to "s "p ( ! runn+ ge> ( ! ma*9e1 su* z ! revolv+ %utt]1 = in/ance1 be+ out ( balance4 ,if !re is undue vibration1 ! ma*9]y %\ld be look$ aft] fir/1 = x is mu* bett] to prev5t ! vibration by remov+ ! cause ?an to seek to re/ra9 x by bolts & braces4 ,if ! ma*9e runs v badly1 x _c be bolt$ d[n ) any satisfactory results4 ,inspection4--,aft] ! ma*9e is l9$ up & runn+ smoo?ly1 ! next /ep %\ld be to inspect e "p ( x ?or\ghly = loose screws1 p9s1 ge>s1 or o!r p>ts4 ,x is be/ to d ?is by beg9n+ at "o end & cont9u+ to ! o!r s t no "p may be ov]look$4 ,upp] ,magaz9e4--,see t ! spr+ 9 ! upp] magaz9e1 or on ! door ( x1 :i* prev5ts ! mom5tum ( ! upp] reel f runn+ (f film aft] ! sprocket has ceas$ pull+1 is 9 good ord] & ! reel true4 ,a crook$ reel w g5]ally cause tr\ble & =ce ! op]ator to keep ! magaz9e door op5 s z to be able to aid ! movem5t ( ! film4 ,fire ,trap4--,! fire trap mu/ next be look$ aft]4 ,! upp] magaz9e1 ! fire trap1 & ! sprockets mu/ all be 9 p]fect alignm5t & ! film mu/ run ?r\gh ! trap )\t t\*+ ei!r side4 ,film we>s ! metal v fa/ & a day's run ) ! film bru%+ "o side ( a valve w %[ decid$ we>4 ,if x is all[$ to run ?is way1 x w soon cut ?r\gh ! side ( ! valve1 =m+ an op5+ 9 :i* ! film w run & 9 :i* x w (t5 cat* & te> splices4 ,special c>e mu/ be ex]cis$ to see t ! traps are kept clean &1 :5 n 9 use1 !y %\ld always be cov]$4 ,! film is drawn ?r\gh ! traps v rapidly & any k9d ( dirt accumulat+ on !m is apt to scrat* x4 ,aft] a fire1 burn$ film is likely to be f\nd 9 ! trap1 & ?is1 :5 cold1 becomes h>d & is difficult to remove4 ,clean+ ,ma*9e4--,aft] ! ma*9e has be5 us$ = a consid]able "t1 x is advisable to wa% out ! ge>s ?or\ghly4 ,n only ! ge>+1 b ! be>+s also1 %\ld be rea*$ by ?is process4 ,if "o has pl5ty ( gasol9e & a suitable receptacle1 ! quicke/ way is to take out ! l5ses & imm]se ! :ole ma*9e = a :ile 9 a vessel fill$ ) gasol9e4 ,x c !n be tak5 out1 work$ a little1 & imm]s$ aga92 ?is process be+ repeat$ until all ( ! old & h>d5$ grease is work$ out4 ,if facilities = imm]s+ ! ma*9e are n at h&1 ! be>+s may easily be clean$ by us+ k]os5e or gasol9e to oil !m & !n runn+ ! ma*9e a little2 ?is w "w all ( ! old grease out ( ! be>+s4 ,! ge>+ c be clean$ 9 ! same way4 ,if gasol9e is us$1 x w quickly evaporate & leave ! ma*9e 9 good ord]4 ,oil+ ,ma*9e4--,aft] ! ma*9e is ?or\ghly clean$1 x may be oil$ aga94 ,! be/ lubricants to be us$ range all ! way f sew+-ma*9e oil to beeswax4 ,beeswax is us$ only = ! ge>+ & only :]e t is some:at worn4 ,x is solid en\gh to comp5sate = "s ( ! we>4 ,t "p ( x :i* works out on ! sides %\ld be wip$ (f at once4 ,!re are _m lubricants to be recomm5d$2 9 g5]al1 h[ev]1 ! p>ticul> k9d to be *os5 dep5ds ^u ! p>ts to be lubricat$4 ,a "p mov+ rapidly ) no great friction c be well s]v$ ) a light lubricant1 b heavi] p>ts1 or p>ts t fit s closely z to cause mu* friction are be/ s]v$ by "s lubricant t has m body4 ,if a light oil is us$1 x w ( c\rse h to be appli$ (t5] ?an a heavy oil4 ,none ( ! extremely light oils %\ld be us$ because !y run (f too fa/4 ,c>e ( ,sprockets4--,hav+ ?us clean$ & oil$ ! ma*9e1 ! next /ep is to look aft] ! sprockets4 ,9 an old ma*9e x is likely t ! sprocket tee? w be s worn z some:at to resemble hooks4 ,a little we> ( ?is k9d w d no great h>m1 b beyond a c]ta9 po9t ( we>1 ! sprocket tee? t5d to c>ry ! film f>!r ?an is necess>y & 9 s do+ te> out ! holes4 ,"s sprockets are made rev]sible & ! tr\ble c be rem$i$ by turn+ ! sprocket :eel ar\nd4 ,9 mo/ cases x w1 h[ev]1 be advisable1 :5 ! old tee? are badly worn1 to get a new set ( sprockets4 ,! sprockets mu/ also be exam9$ = accumulation ( dirt1 = 9 case !re is mu* dirt on a sprocket1 x w n guide ! film prop]ly4 ,! dirt w cause x to jump1 & ?us br+ ab\t an un/eady picture2 or1 if ! accumulation ( dirt is suffici5t1 x may ev5 cause ! film to jump (f ! sprocket4 ,hundr$s ( feet ( film h be5 ru9$ 9 ?is way4 ,! sprockets %\ld be clean$ e day ) a suitable bru%4 ,an op]ator too c>eless to clean 8 ma*9e prop]ly1 is also z a rule too c>eless to wat* ! picture prop]ly2 & he sudd5ly f9ds himself ) a l5g? ( film ru9$ by sprocket tee? :i* h cut a r[ ( holes ?r\gh ! c5t] ( x4 ,! sprocket %\ld be made to align p]fectly ) ! upp] & l[] magaz9es1 ! fire valves1 ! film gate1 & ! pa? ( ! film4 ,!y may be align$ ) a /raight edge made ( a flexible piece ( /eel or1 if no?+ else is available1 a piece ( film may be plac$ ^u ! sprockets4 ,be sure to exam9e ! film c>efully be=e us+ x = ?is purpose2 old film is apt to be w>p$4 ,! film mu/ fit p]fectly 9 ! ap]ture & on ! diff]5t sprockets4 ,! sprockets mu/ h little or no end play1 especially ! int]mitt5t1 or x may cause ! picture to wiggle sideways4 ,! idl]s1 or press] roll]s1 %\ld n fit tight en\gh to b9d1 b mu/ fit closely en\gh to hold ! film securely4 ,9 ! adju/m5t ( ^! & all o!r p>ts ( a mov+ picture ma*9e1 consid]able practice & judgm5t are necess>y to e/imate h[ mu* fre$om ( movem5t is p]missible4 ,adju/+ ,int]mitt5t ,sprocket4--,! 8,g5eva0 we>s rapidly :5 x is n well oil$ or protect$2 & x becomes necess>y to adju/ x4 ,!re are o!r ways ( do+ ?is b g5]ally x is done by means ( an ecc5tric bu%+ :i* mu/ be set to comp5sate = ! we>4 ,9 _m op]at+ rooms1 !re is a wide range ( temp]ature &1 z heat exp&s ! metals1 !y w b9d unduly :5 !y become w>m$ up1 if ! /> & cam :eel are set too close :ile cold4 ,9 _m ma*9es ! heat f ! lamp w>ms !m up irrespective ( ! temp]ature 9 ! op]at+ room4 ,automatic ,fire ,%utt]4--,"s means ( adju/+ & regulat+ ! automatic fire %utt] is usually provid$2 ?is %\ld be adju/$ s t x w n rise be=e ! ma*9e is 9 motion & w fall be=e x has come to re/4 ,"u no conditions %\ld ! /ation>y film be all[$ 9 ! pa? ( ! light4 ,!re are fire %utt]s t d n dep5d ^u ! motion ( ! ma*9e1 b are rais$ z soon z ! h&le is press$ to give motion to ! ma*9e4 ,?is type ( %utt] is rais$ z soon z ! h&le is press$ & may expose ! /ation>y film to ! light4 ,su* a %utt] %\ld n be tol]at$ at all4 ,! fire %utt] %\ld be c>efully te/$ to see t x op]ates prop]ly "u all conditions4 ,if "o is n acqua9t$ ) ! p>ticul> type ( fire %utt] 9 use1 x is advisable = him to te/ x ) ! lamp turn$ on x = "s "t4 ,"s %utt]s are s ?9 & are plac$ s close to ! film !y are suppos$ to protect1 t x is possible to fire ! film ?r\gh !m4 ,! ,revolv+ ,%utt]4--,9 "s ma*9es ! light is %ut (f be=e ! film beg9s to move1 & 9 o!rs a v slight movem5t ( ! film is p]mitt$ be=e ! %utt] closes out ! light entirely4 ,! g5]al object ( ! %utt] is to %ut (f ! light :ile ! film is mov+ & to int]rupt ! long p]iod ( light s t x may n affect ! eye too /rongly & give rise to ! s5sation ( flick]4 ,! exact mann] ( sett+ ! %utt] v>ies ) diff]5t ma*9es1 b 9 g5]al ! above consid]ation mu/ be kept 9 view4 ,:]e a %utt] has sev]al blades1 x is always ! l>g] "o t %uts (f ! light :ile ! film is mov+ & ?is is ! only "o to :i* any att5tion mu/ be paid :ile sett+4 ,! be/ te/ = ! sett+ ( ! %utt] is ! appe>ance ( ! picture4 ,! be/ k9d ( picture ) :i* to judge a %utt] is "o t has /rong contra/s ( light & d>kness4 ,if a picture conta9s a v bright object1 ! travel gho/ w appe> if !re is any motion :ile ! light is on ! film4 ,if ! %utt] is set too late1 ! travel gho/ w be 9 ! l[] "p ( ! scre52 & if too soon1 9 ! upp]4 ,if ! %utt] is made too small1 ! travel gho/ _c be entirely elim9at$ b mu/ be divid$ half on ! l[] & half on ! upp] side ( ! picture4 ,! travel gho/ & o!r imp]fections ( a picture are mu* m noticeable to p]sons close to ! scre5 ?an to ^? f> away4 ,z ! op]ator himself is ! f>!/ away ( all spectators1 he is likely to miss _m imp]fections t are pla9ly visible to ! audi5ce4 ,= ?is reason _m op]ators h op]a glasses ?r\gh :i* !y view _! pictures4 ,fram+4--,:5 ! ma*9e is f9ally ?read$1 ! film %\ld be s plac$ on ! upp] sprocket t1 ) a prop] loop1 ! picture w be 9 frame :5 ! fram+ lev] is ab\t 9 ! middle position4 ,?is position w all[ ! op]ator to frame ei!r up or d[n )\t s]i\sly affect+ ! loop4 ,! fram+ is be/ done by look+ at ! picture ?r[n ^u ! scre54 ,film ,gate4--,! film gate ne$s special att5tion :5 new film is be+ us$4 ,v (t5 new film is s damp t "s ( ! emulsion /icks to ! gate4 ,wet film runn+ ?r\gh a ma*9e makes x "w h>d & is likely to cause mu* tr\ble4 ,) su* film x is (t5 necess>y to /op dur+ a run & clean (f ! gate & x is always necess>y to d s aft] ea* run4 ,nev] use a %>p tool or any?+ t may scrat* ! gate or r\gh5 ! be>+ surfaces :]e ! film runs4 ,! gate mu/ be wat*$ closely = we>2 if worn too mu*1 ! picture may be out ( focus or jump 9 all directions4 ,t5sion ,spr+s4--,! t5sion spr+s w repay c>eful /udy by ! op]ator4 ,! object ( ! spr+s is tw(old3 ,fir/1 to hold ! film flat1 & second1 to introduce suffici5t friction to ov]come quickly ! slight mom5tum :i* ! film has acquir$ :ile 9 motion4 ,! spr+s %\ld be j tight en\gh to d ?is4 ,! pressure ( ! spr+s necess>y to ov]come ! mom5tum ( ! film is proportional to ! spe$ at :i* ! film moves4 ,if ! film is to be run at a high rate ( spe$--z is (t5 ! case :5 a cr[d is wait+ outside ! doors--! t5sion mu/ be increas$1 unless x 0 orig9ally great en\gh to hold ! film at ?is rate ( spe$4 ,z ! film v>ies 9 ?ickness1 ! adju/m5t _c be made too close2 b ! spr+s mu/ be made tight en\gh s t !y w hold ! film at ! highe/ rate ( spe$ :5 ! ?9ne/ "p ( ! film is pass+ ?r\gh4 ,if ! spr+s are n suffici5tly tight1 ! picture w seem to move a trifle4 ,!y mu/ be j tight en\gh to prev5t ?is at ! highe/ rate ( spe$ at :i* ! ma*9e is to op]ate4 ,! ,take-,up4--,! l[] sprocket exi/s = ! purpose ( re/ra9+ ! take-up f pull+ on ! int]mitt5t sprocket4 ,!re is ?us actually always a /ra9 t ! "o puts on ! o!r4 ,= ?is reason ! t5sion on ! take-up %\ld be no great] ?an necess>y4 ,excessive t5sion w increase ! we> on ! ma*9e2 may cause ! te>+ ( _m splices2 & w cause ! ma*9e to run h>d1 ?us impos+ extra labor on ! op]ator4 ,:ile ! l[] reel is ne>ly empty1 ! /ra9 is small2 b z x fills up1 ! /ra9 becomes great]4 ,! driv+ :eel or belt mu/ move at a fix$ rate ( spe$ :ile ! slip ( ! driv5 :eel becomes great] ) e turn4 ,?us ! en]gy exp5d$ 9 friction becomes great] z ! picture progresses4 ,defective belt+1 crook$ reels1 or poor adju/m5t ( t5sion are ! mo/ frequ5t cause ( annoyance 9 ! take-up & ! take-up z a :ole gives probably m tr\ble ?an any o!r "p ( ! equipm5t4 ,cov]4--,e ma*9e %\ld be cov]$ :5 n 9 use & ! cov] %\ld be du/ tight4 ,gett+ ,ready = ! ,%[4--,! fir/ ?+ = ! op]ator to d be=e ent]+ ! op]at+ room is to put away all smok+ p>aph]nalia he may h ab\t him4 ,no smok+ tobacco or mat*es %\ld ev] be f\nd inside ( any op]at+ room4 ,aft] tak+ ?is precaution ! next ?+ w be to rew9d & inspect ! films to be us$ = ! next p]=mance4 ,if ! reel happ5s to be prop]ly w\nd :5 receiv$1 x is n absolutely necess>y to rew9d x &1 9 an em]g5cy1 "o may take a *ance & run x ?r\gh )\t previ\s inspection4 ,:5 possible1 h[ev]1 ! op]ator %\ld always inspect 8 film be=e us+ & also famili>ize himself ) its cont5ts4 ,a film is be/ inspect$ by rew9d+ x sl[ly f "o reel onto ano!r1 gripp+ x ) a g5tle pressure1 & all[+ x to run betwe5 ! f+]s4 ,?is me?od w cat* all splices & also all split films4 ,films are frequ5tly split along ! l9e ( ! sprocket holes4 ,! film %\ld be run ?r\gh ! f+]s 9 ?is mann] twice3 once to cat* su* irregul>ities z make !mselves manife/ along ! out] edge & aga9 to cat* ! defects t exi/ only 9 ! middle ( ! film4 ,e splice %\ld be c>efully inspect$ to note h[ ! sprocket holes mat* & :e!r ! splice w ?r[ ! picture out ( frame4 ,all splices t are n prop]ly made %\ld be re-made z direct$ 9 ,*apt] ,,vi4 ,if !re is suffici5t "t1 x w\ld be well to run ! film ?r\gh ! ma*9e 9 ! regul> way4 ,?us ! op]ator c famili>ize himself ) ! picture & note e place :]e improvem5ts c be made by adju/+ ! spe$1 = v (t5 a picture may be improv$ by sl[+ d[n or increas+ ! spe$ 9 c]ta9 sc5es4 ,! flick] v>ies ) ! illum9ation2 ! bright] ! light ! great] w be ! t5d5cy to flick]1 if ! ma*9e is n run at prop] spe$4 ,! op]ator %\ld "k be=e h& j :5 8 brighte/ sc5es w come on s z to adju/ ! spe$ or1 9 case he mu/ run sl[ly1 s z to r$uce ! flick] by r$uc+ ! illum9ation4 ,runn+ ! film ?r\gh w also %[ e place :]e ! picture goes out ( frame & all su* places c be correct$4 ,all bad places %\ld be cut out ( ! film1 b n m ?an necess>y4 ,e additional section cut out ( a film w increase ! j]k9ess ( ! motion4 ,a few are n notic$1 b "o (t5 sees 9 old reels1 sc5es t are simply ridicul\s because too mu* film has be5 cut out4 ,su* effects are especially noticeable if a picture is run sl[ly4 ,! op]ator mu/ always be prep>$ to run pictures at abnormal spe$s4 ,x is bad practice to d s b (t5 unavoidable2 = in/ance1 if ! next numb] on ! program is delay$1 x is desirable to ext5d ! picture until x is ready 9 ord] t ! audi5ce may n be dissatisfi$2 or if all ! seats are fill$ & p are wait+ outside1 ! manag] may dem& extra spe$ s z to make room = ! outsid]s4 ,! op]ator :o is wise & has _h exp]i5ce w provide himself ) a receptacle 9 :i* he c /ore ! pieces he cuts out ( films4 ,sav+ su* pieces & tak+ !m to ! ex*ange w (t5 make an impression ^u ! ex*ange managem5t & induce great] c>e 9 ! inspection ( films at ! ex*ange4 ,su* pieces w sometimes be good evid5ce 9 ! h&s ( an op]ator1 too1 9 case he is *>g$ ) hav+ damag$ a film4 ,:ile ! film is be+ run ?r\gh ! ma*9e1 x c also be measur$4 ,e turn ( ! crank means "o foot ( film4 ,be=e ! film is w\nd ^u ! reel f :i* x is to be exhibit$1 an opaque piece ( film ab\t two feet 9 l5g? %\ld be atta*$ to ! tail end ( ! film4 ,?is piece ( film w 9 "s cases s]ve a d\ble purpose4 ,) "s ma*9es ! film c be rew\nd f ! l[] magaz9e into ! upp] )\t tak+ x out ( ei!r1 if ?is tail piece is long en\gh to rema9 fa/ to ! upp] reel aft] ! :ole film is run (f ! upp] reel4 ,?us ! op]ator :5 ?r\gh runn+ ! picture may imm$iately *ange 8 crank &1 )\t delay1 beg9 to rew9d4 ,! ma9 purpose ( ?is tail piece1 h[ev]1 is to %ut (f ! light imm$iately aft] ! la/ section ( ! picture has be5 exhibit$4 ,if ! light is left on ! scre5 :ile ! op]ator sl[s d[n ! ma*9e1 x w cause a disagreeable flick] to appe> be=e ! eyes ( ! audi5ce imm$iately aft] ! picture is ov]1 & ?us leave an unpleasant impression4 ,! beg9n+ ( ! film %\ld be provid$ ) a lead] f ?ree to five feet long4 ,! purpose ( ?is lead] is to all[ ! op]ator "t to frame 8 picture & get 8 lamp adju/$ be=e ! title appe>s1 or is f9i%$1 s t :5 ! picture actually beg9s1 ev]y?+ w be runn+ smoo?ly4 ,! film mu/ be rew\nd ^u ! reel 9 su* a mann] t :5 ?read$1 ! emulsion side w face ! lamp4 ,if ?is is n done1 ! titles w read f "r to left in/ead ( f left to "r z !y %\ld4 ,x w be well = ! op]ator to =m ! habit ( regul>ly te/+ 8 film by ! actual projection to see t 8 titles are "r4 ,!re are (t5 _m o!r ?+s to ?9k ( & cases ( abs5t-m9d$ness are n uncommon4 ,if ! title %[s wrong1 ! reel may be tak5 out & turn$ ar\nd2 ?is w rev]se x1 b ord9>ily x is be/ to w9d x 9 "o c]ta9 way4 ,e op]ator %\ld h a full supply ( good reels = use 9 ! ma*9e & %\ld nev] let ^! get out ( 8 h\se4 ,! reels furni%$ by ! ex*anges are (t5 v bad & if p]*ance a real good "o is s5t out1 "s wide-awake op]ator w surely keep x4 ,al?\gh x is be/ to rew9d a reel z sl[ly z y\r "t w p]mit1 x is necess>y sometimes to d x v rapidly4 ,! reel f :i* ! film is be+ unw\nd %\ld be "u a /eady t5sion & "s =m ( brake is (t5 provid$4 ,! practice ( 8pull+ d[n10 :i* is indulg$ 9 by s _m op]ators1 is highly repreh5sible4 ,x causes ! emulsion side ( ! film to slide ov] ! o!r & any dirt or du/ t may be betwe5 ! two is ?us gr\nd into !m4 ,! scrat*es ?us caus$ soon fill up ) dirt & cause /reaks 9 ! picture :i* are commonly t]m$ 8ra940 ,! dirt--especially ! c>bon du/1 :i* is s pl5tiful 9 an op]at+ room & :i* is v %>p & cuts badly into ! emulsion or ! celluloid--disfigures ! picture v mu*4 ,a good film box %\ld be locat$ 9 e op]at+ room & x %\ld be s conv5i5tly locat$ t ! op]ator w use x 9 pref]5ce to any?+ else4 ,su* a box %\ld be provid$ ) automatic self-clos+ cov]s & %\ld be ne> ! floor1 z ! film is less liable to dry out !re ?an if plac$ ne> ! ceil+ :]e ! heat is great]4 ,no?+ :atev] %\ld be plac$ ^u ! floor itself & x %\ld be kept absolutely clean4 ,al?\gh x is v bad practice to run film on ! floor & x %\ld n be done1 !re are occasions :5 x w be done &1 if ! floor is cle> ( all ob/ruction1 ! haz>d ( do+ s is mu* r$uc$4 ,an op]ator :o1 hav+ tr\ble ) 8 take-up & hav+ run ! film on ! floor1 has _h x entangl$1 w appreciate ?is fact4 ,! spasmodic bur/s ( applause :i* an impati5t audi5ce is apt to (f] :ile ! %[ is be+ delay$ are n especially com=t+ to any "o 9 su* a position4 ,"u no circum/ances %\ld film ev] be left expos$4 ,occasional small fires at ! ap]ture plate are unavoidable & 9 su* cases ! op]ator w seek to te> (f ! burn+ film & ?r[ x on ! floor1 & x may !n ignite ! film ly+ ab\t4 ,=m ! habit ( keep+ y\r film "u cov]2 & make up y\r m9d t x is absolutely necess>y4 ,keep+ films "u cov] w also t5d to save !m f dry+ out & prev5t accumulation ( du/4 ,a slide ) ! words 8,j a mom5t please10 or "s equival5t expression1 w reassure ! audi5ce2 "o %\ld always be kept 9 place & :5 any tr\ble causes an int]ruption ( ! %[1 ! lamp %\ld be pu%$ ov] ?us exhibit+ ?is sign4 ,! habit ( pu%+ ! lamp ov] 9 case ( int]ruption is also a v good "o4 ,x is ! simple/ & mo/ natural way ( tak+ ! light (f ! film & satisfy+ ! audi5ce at ! same "t4 ,?is practice %\ld become a habit4 ,x w be a great protection aga9/ fire 9 addition to ! o!r safety devices4 ,all ! "w ( mak+ ready %\ld if possible be done be=e a consid]able "p ( ! audi5ce is 9 ! h\se4 ,x is be/ to let none ( !m see ! process ( gett+ ! %[ 9 read9ess4 ,z has be5 /at$ be=e1 an occasional fire at ! ap]ture is unavoidable4 ,sometimes pieces ( film are torn loose1 /ick :]e !y are subject to ! light1 & 9 "t cat* fire4 ,a fire ?us />t$ may easily consume all ( ! film betwe5 ! two magaz9es & w progress sl[ly t[>d ! l[] "o1 b t[>ds ! upp] "o v rapidly4 ,if ! doors ( ! magaz9es are tightly clos$ & fit tight & if ! fire traps are 9 good ord]1 !re w be b a small *ance ( fire gett+ at ! rolls ( film t may be 9 ei!r magaz9e4 ,e ef=t %\ld1 h[ev]1 be made to ext+ui% x be=e x rea*es ! fire traps4 ,j :at c be done dep5ds ^u ! design ( ! ma*9e4 ,9 ord] to be prep>$ = su* an em]g5cy1 ! op]ator %\ld /udy 8 ma*9e & decide :at w\ld be be/ to d4 ,9 _m cases ! film c be torn (f be=e ! fire ext5ds to ! magaz9e & ?us break ! connection4 ,9 "s ma*9es ! film runs 9 su* a n>r[ groove t ! fire is g5]ally ext+ui%$ !re )\t any outside help4 ,"s op]ators h be5 kn[n to op5 _! magaz9es & attempt to remove ! film aft] a fire _h />t$1 result+ 9 burn+ all _! film4 ,x is f> bett] to leave ! film 9 ! magaz9e & tru/ to ! fire traps ?an to attempt to remove x4 ,no visitors %\ld be all[$ 9 any op]at+ room dur+ ! "t t ! audi5ce is 9 ! h\se1 m especially :5 ! "t = op5+ ! %[ approa*es4 ,!re %\ld be no?+ to di/ract ! op]ator's att5tion f 8 duties4 ,! arc lamp %\ld be />t$ a few m9utes be=e ! %[ is to beg9 s t ! electrodes may burn to _! prop] %ape & ! light be adju/$4 ,be=e ! %[ beg9s1 ! h\se %\ld be made d>k = a few m9utes4 ,?is w make ! picture appe> bright]4 ,9 case ! film te>s dur+ a run1 "s op]ators h ! habit ( p9n+ ! pieces toge!r ) ! int5tion ( mak+ ! splice aft] ! picture is run4 ,?is practice is well en\gh = an op]ator :o feels sure t he w n =get ab\t ! p91 b ) "o :o is =getful or abs5t-m9d$1 or :o has a lot ( o!r duties :i* might take 8 m9d (f ! film1 x is a bad practice4 ,! film may be rew\nd ) ! p9 rema9+ 9 position & cause v s]i\s tr\ble4 ,x is saf] to put ! film on ! take-up )\t p9n+4 ,9 a g5]al way ! po9ts allud$ to 9 ! foll[+ li/ %\ld be c>efully look$ aft]4 ,?is is a li/ :i* is us$ by ! ,electrical ,inspection ,bureau ( ! ,city ( ,*icago 9 *eck+ up op]ators & _! equipm5t4 ,!atre address444444444444444444444444444444444 4444444444444444444444 ,p]m4 ,op]ator's "n 4444444444444444444444444444444444444444 444444444 ,temp4 ,address44444444444444444444444444444444 44 ,lic4 ,no4 4444444444444444444 ,,mov+ ,,picture ,,ma*9e ,,inspection4 ,an x indicates defect2 a *eck1 satisfactory condition4 ---------------------------------------- --------------------------- #a ,smok+8 #be ,fan ,motor8 ---------------------------------------- --------------------------- #b ,mat*es8 #bf ,gu>ds on inc4 lights8 ---------------------------------------- --------------------------- #c ,condition ( ,films8 #bg ,unau?oriz$ p]sons8 ---------------------------------------- --------------------------- #d ,magaz9e clos$8 #bh ,rew9d approv$8 ---------------------------------------- --------------------------- #e ,film expos$8 #bi ,rew9d location8 ---------------------------------------- --------------------------- #f ,arc enclos$8 #cj ,rheo/at1 #e ft4 above floor8 ---------------------------------------- --------------------------- #g ,gu>d fa/5$8 #ca ,rheo/at1 contacts enclos$8 ---------------------------------------- --------------------------- #h ,upp] fire gu>d8 #cb ,rheo/at1 safe location8 ---------------------------------------- --------------------------- #i ,l[] fire gu>d8 #cc ,box = films1 approv$8 ---------------------------------------- --------------------------- #aj ,upp] magaz9e approv$8 #cd ,box = films1 cov]8 ---------------------------------------- --------------------------- #aa ,l[] magaz9e approv$8 #ce ,%utt]s1 guides8 ---------------------------------------- --------------------------- #ab ,upp] magaz9e1 lock well8 #cf ,%utt's self-clos+1 supports8 ---------------------------------------- --------------------------- #ac ,l[] magaz9e1 lock well8 #cg ,boo? l9+8 ---------------------------------------- --------------------------- #ad ,light %utt]8 #ch ,floor8 ---------------------------------------- --------------------------- #ae ,fuses enclos$8 #ci ,%elv+8 ---------------------------------------- --------------------------- #af ,fuses1 prop] size8 #dj ,g5]al appe>ance8 ---------------------------------------- --------------------------- #ag ,inc4 circuit8 #da ,door1 self-clos+8 ---------------------------------------- --------------------------- #ah ,arc swit*es1 enclos$8 #db ,box (fice8 ---------------------------------------- --------------------------- #ai ,arc swit*es1 control #dc ,unapprov$ display8 rheo/at8 ---------------------------------------- --------------------------- #bj ,arc swit*es1 condition8 #dd ,ma9 cut\t cab9et8 ---------------------------------------- --------------------------- #ba ,h[ mu* op5 arc wire8 #de ,em]g5cy cut\t cab9et8 ---------------------------------------- --------------------------- #bb ,h[ mu* op5 inc4 wir+8 #df ,numb] em]g5cy lights8 ---------------------------------------- --------------------------- #bc ,op5 contacts8 #dg ,fan motors auditorium8 ---------------------------------------- --------------------------- #bd ,flexible or ,,bx cord8 #dh ,rheo/at 9 base4 cond48 ---------------------------------------- --------------------------- #di ,exits444448 ,gas444448 ,sp]m ,oil444448 ,electric444448 ---------------------------------------- ------------------------------ 44444444444444444444444444444 ,inspector4 ,^! defects mu/ be correct$ )944444444444444days4 ,! ,electrical ,inspection ,bureau mu/ be notifi$ z soon z repairs are made4 ,,*apt] ,,viii4 ,,light4 ,light is emitt$ f a lum9\s body4 ,a lum9\s body is "o 9 :i* all ( ! p>ticles are conceiv$ to be 9 viol5t motion1 :i* motion is transmitt$ to a suppos$ e!r4 ,! exi/5ce ( su* e!r _c be demon/rat$1 b x is suppos$ to exi/ because x is impossible to ?9k ( any?+ be+ transmitt$ except ?r\gh "s m$ium4 ,?is e!r is a r impond]able sub/ance2 x is suppos$ to p]vade all space2 & x exi/s 9 all matt] & 9 e vacuum4 ,x is suppos$ to be ela/ic )\t weight & capable ( transmitt+ motion )\t loss ( en]gy or friction4 ,x is1 h[ev]1 assum$ to be modifi$ to "s ext5t by ! matt] 9 connection ) :i* x exi/s4 ,?us ! rate ( transmission ( light waves is diff]5t = air1 glass1 wat]1 & o!r sub/ances ?r\gh :i* !y may pass & su* bodies z are entirely opaque are suppos$ to suppress ! e!r vibrations1 result+ 9 light entirely4 ,light is !n a mode ( motion ( ?is univ]sal e!r :i* p]vades all space ev5 to ! f>!/ />4 ,! motion ( ?is e!r is conceiv$ to be ab\t z illu/rat$ 9 ,figure #ec4 ,if we take a heavy /r+ or a small rope &1 /ret*+ x reasonably taut1 j]k x =w>d & back quickly a few times1 x w be se5 to move & assume ! appe>ance %[n 9 ! figure2 & t portion %[n betwe5 ! two v]tical l9es repres5ts "o complete wave4 ,illu/ration3 ,,figure #ec4 ,! assumption ( ?is e!r & ! vibratory motions ( x =m ! only explanation t is capable ( acc\nt+ = all ( ! ph5om5a ( light4 ,all o!r !ories advanc$ h fail$ to /& ! te/2 soon] or lat] "s ph5om5a h appe>$ :i* c\ld n be expla9$ by !m4 ,light waves are kn[n to travel ?r\gh space 9 /raight l9es until !y meet ) "s m$ium :i* is capable ei!r ( reflect+1 refract+1 or absorb+ !m4 ,! rectil9e> propagation ( light1 consi/+ ( vibratory motion1 is "o ( ! mo/ difficult p>ts ( ! !ory to expla94 ,x involves r deep /udy & m ma!matics ?an ! scope ( ?is "w w w>rant4 ,suffice x to say t ! rectil9e> propagation is br\ght ab\t ?r\gh ! int]f]5ce ( light waves4 ,an analogy ( ?is c be f\nd 9 a /ream ( wat]4 ,x is well kn[n t a /ream ( wat] issu+ f ! nozzle ( a g>d5 hose moves 9 a /raight l9e until gradually =c$ into a spray by ! resi/ance ( ! air4 ,yet ! wat] pass+ ?r\gh ! hose is int]f]$ ) on all sides & on all sides !re is a t5d5cy to deflect x4 ,if ! wat] 7 to move along sl[ly s t we c\ld obs]ve ! action on "o side indep5d5tly ( ! balance ( ! /ream1 we %\ld see a s]ies ( waves be+ =m$ by e p>ticle ( ! hose :i* (f]s resi/ance to ! fl[4 ,! waves =m$ 9 ! int]ior ( ! hose on all sides are int]f]$ ) by waves f all o!r directions & ! result is motion 9 a /raight l9e4 ,9 a simil> way x may be conceiv$ t ! millions ( light waves emitt$ f a lum9\s body int]f]e ) ea* o!r & ?us cause light rays to move 9 a /raight l9e4 ,light is a =m ( en]gy & c be conv]t$ into o!r =ms ( en]gy4 ,x c be conv]t$ into heat1 = in/ance1 or c be us$ to produce *emical effects4 ,light diff]s f heat only 9 ! rate ( vibration & ! l5g? ( ! e!r waves4 ,heat c be reflect$ 9 ! same mann] z light1 z ! foll[+ exp]im5t w %[3 ,arrange two ord9>y reflectors z %[n 9 ,figure #ed4 ,9 ! focal po9t ( "o1 place a heat$ iron ball or some?+ ( ! k9d2 if ?is be hot en\gh1 x w ignite pap] susp5d$ 9 ! focal po9t ( ! o!r reflector1 al?\gh a !rmomet] plac$ any:]e betwe5 ! two reflectors w give only a small indication ( a rise 9 temp]ature4 ,illu/ration3 ,,figure #ed4 ,all light rays z well z heat rays are 9 !mselves invisible2 we c see only ! object :i* emits or reflects !m4 ,if a beam ( light be all[$ to ent] a d>k5$ room1 z %[n 9 ,figure #ee1 we %all probably be able to see ! :ole pa? ( ! rays illum9at$1 z well z ! spot on ! floor4 ,b ?is w be because ( p>ticles ( du/ 9 ! air :i* reflect ! rays to our eyes4 ,if we introduce "s smoke into ! room1 we %all see ! light mu* m pla9ly because !re are n[ m p>ticles ( matt] to reflect x4 ,on ! o!r h&1 if special precautions are tak5 to h ! air absolutely cle> ( du/1 we %all be able to see no?+ b ! spot on ! floor4 ,illu/ration3 ,,figure #ee4 ,light travels ?r\gh space at ! rate ( ab\t #ahf1jjj miles p] second4 ,:ite light is a comb9ation ( light ( _m colors1 b ! spe$ ( transmission is ! same = all colors4 ,! l5g? ( waves & ! rate ( vibrations1 h[ev]1 v>y4 ,! r$ rays h ! longe/ waves & ! sl[e/ rate ( vibration2 !y vibrate ab\t ?ree hundr$ n9ety-five billion times p] second & ! wave l5g? is ab\t #j4jjjh millimet]s4 ,! violet rays possess a wave l5g? ( ab\t sev5 hundr$ sixty-?ree billion p] second4 ,!re are light waves :i* are long] ?an ! r$ rays & ^! are kn[n z infra r$4 ,!y are n visible to ! eye b _! exi/5ce c be prov$ 9 _m ways4 ,light waves %ort] ?an ! violet are also invisible & are kn[n z ultra violet4 ,^! h mu* importance 9 photography & to ?is class belong ! ,x ray4 ,illu/ration3 ,,figure #ef4 ,we h m5tion$ above t :ite light is a comb9ation ( light rays ( _m colors4 ,?is c be prov$ by ! foll[+ exp]im5ts3 ,if we arrange to h a beam ( sunlight pass ?r\gh a small hole into a d>k5$ room1 x w pass to ! wall on ! opposite side 9 a /raight l9e & give u :ite illum9ation ^u a small spot4 ,if we n[ arrange a prism 9 ! pa? ( ?is ray or beam ( light1 we %all f9d t ! light no long] passes /raight to ! wall b t in/ead1 x is b5t 9 a c]ta9 direction & fur!rmore %[s u a brilliant array ( colors4 ,?is is illu/rat$ 9 ,figure #ef4 ,! rays are ?us %[n to be sep>at$ into _! con/itu5t colors2 r$ is %[n at ! top & ! foll[+ colors m]ge imp]ceptibly into "o ano!r--orange1 yell[1 gre51 blue1 indigo1 & f9ally violet at ! bottom4 ,! reason = ?is *ange is t ! rays ( light on ent]+ ! glass are sl[$ d[n--^? ( ! high] rate ( vibration m ?an ! o!rs4 ,! violet rays are ?us said to be m refrangible ?an ! r$1 = in/ance4 ,! colors ?us produc$ are simple colors4 ,?is is prov$ by ! fact t if ! light is pass$ on ?r\gh ano!r prism1 x w be aga9 reflect$ b w n be resolv$ into o!r colors2 al?\gh :i*ev] color is c>ri$ to ! next prism w spread out & %[ f9] gradations 9 its color4 ,illu/ration3 ,,figure #eg4 ,! colors giv5 above are ^? obta9able f ! decomposition ( sunlight & make up :at is kn[n z ! sol> spectrum4 ,if in/ead ( sunlight "s o!r illum9ant be us$1 ! arrangem5t ( colors w be diff]5t2 & x has be5 f\nd possible to tell f ! colors ( ! spectrum :at sub/ances are burn+1 or heat$ to a lum9\s degree1 9 ! s\rce f :i* ! light comes4 ,?is me?od is kn[n z spectrum analysis4 ,!re are sev]al ways 9 :i* light1 :i* has ?us be5 sep>at$ into its fundam5tal colors1 c be re-compos$ s z to give u :ite light aga94 ,"o ( ^! me?ods consi/s 9 arrang+ an inv]t$ prism to receive ! light1 z %[n 9 ,figure #eg4 ,! rays leave ! second prism p>allel & produce ! effect ( :ite light4 ,ano!r me?od consi/s 9 ga!r+ ! rays f ! prism by a l5s1 z %[n 9 ,figure #eh4 ,fur!rmore1 if we take a disc & pa9t ! colors ( ! sol> spectrum ^u x 9 ! prop] proportions1 z indicat$ 9 ,figure #ei1 & cause ?is disc to be rapidly revolv$1 we %all see x z almo/ :ite4 ,illu/ration3 ,,figure #eh4 ,illu/ration3 ,,figure #ei4 ,ano!r fact :i* goes to prove ! undulatory1 or motion1 !ory ( light is t two s\rces ( light arrang$ to oppose ea* o!r c actually be made to produce d>kness4 ,to d ?is1 ! waves ( "o s\rce ( light mu/ be made s t !y exactly oppose ^? ( ! o!r2 ?us !y de/roy ea* o!r & de/roy :at light !re is 9 ei!r4 ,!re are o!r me?ods1 b ?is c be p>tially accompli%$ 9 ! foll[+ mann]3 ,two small mirrors ( black glass or ( metal are plac$1 z %[n 9 ,figure #fj1 v close toge!r & s t !y =m an angle ( ne>ly #ahj degrees4 ,a beam ( light arrang$ to fall ^u bo? ( ! mirrors w be reflect$ 9 su* a mann] t ! two halves int]f]e ) ea* o!r & cause b&s ( light & d>kness to appe>4 ,! d>k l9es are due to ! opposition & nullification ( c]ta9 ( ! light waves4 ,illu/ration3 ,,figure #fj4 ,illu/ration3 ,,figure #fa4 ,! int5sity ( light dim9i%es directly z ! squ>e ( ! di/ance ?r\gh :i* x is transmitt$4 ,?is is illu/rat$ 9 ,figure #fa4 ,! light1 />t+ f a po9t1 is limit$ by ! size ( ! fir/ squ>e at ! left2 x spreads out m & m1 & illum9ates l>g] & l>g] spaces4 ,exact measurem5t w %[ t ! spaces illum9at$ by a ray ( light are always exactly proportional to ! squ>e ( ! di/ance f ! po9t ( light4 ,?is law1 h[ev]1 applies /rictly only if ! di/ances consid]$ are long comp>$ to ! s\rce ( light1 s t ! light may be consid]$ z be+ a ma!matical po9t1 t is1 hav+ no physical dim5sions4 ,if ! s\rce ( light1 = in/ance1 7 ( ! same size z ! fir/ op5+ & ( uni=m int5sity !re w\ld result ! same int5sity ( illum9ation ( a simil> space at all di/ances4 ,!re w\ld1 h[ev]1 be an out] fr+e ( light :i* w\ld be proportional to ! law ( inv]se squ>es4 ,_m reflectors are arrang$ to ?r[ v ne>ly p>allel rays2 & ) ^! ! int5sity rema9s ! same except = absorption1 :i* is ord9>ily n v great4 ,we see ?+s only ?r\gh ! rays ( light !y reflect4 ,all color$ bodies h ?is peculi>ity1 viz41 t !y are capable ( reflect+ only su* rays z make up ! color ! body is said to possess4 ,a r$ body1 = in/ance1 absorbs all colors except r$ & reflects r$ only4 ,a black body absorbs all rays & a p]fectly dull black body is visible only by contra/2 t is1 we d n see x b we are aw>e t !re is some?+ invisible be=e our eyes4 ,:5 we are 9 a p]fectly d>k room1 we see no?+ b we h blackness be=e our eyes4 ,a p]fectly :ite body is "o :i* reflects all ( ! rays ( light & absorbs none4 ,:5 we view ?+s ?r\gh color$ glasses1 we see !m only 9 ! colors :i* ! glass w transmit4 ,if we view a r$ body ?r\gh a gre5 glass or "u a gre5 light1 x w appe> black because x is capable ( reflect+ only r$ rays & 9 ! gre5 light !re are no r$ rays2 h5ce !re is no?+ to be reflect$ & ! r$ appe>s black4 ,,*apt] ,,ix4 ,,pr9ciples ,,( ,,vision4 ,?r\gh ! m$ium ( our eyes we see objects by means ( ! light :i* is reflect$ f !m4 ,?is light ent]s ! eye & =ms an inv]t$ image ( ! object ^u ! ret9a1 j z an inv]t$ image is =m$ ^u ! gr\nd glass ( a cam]a4 ,?is impression made ^u ! eye is correct$ automatically1 s t1 al?\gh we see ev]y?+ upside d[n1 we are n at all aw>e ( s do+4 ,! pro( ( ?is peculi>ity ( ! eye is f\nd 9 cases :]e p]sons born bl9d h lat] ?r\gh op]ations acquir$ sight4 ,9 ! eyes ( slaught]$ cattle also ! image c be se5 inv]t$4 ,a fur!r pro( t we are able ?us to adju/ ourselves is f\nd 9 ! exp]i5ce ( p]sons us+ cam]as ) gr\nd glass scre5s4 ,! image on ^! scre5s is always inv]t$ bo? horizontally & v]tically4 ,! us] soon le>ns to see 8 object1 al?\gh inv]t$1 9 ! natural way1 t is1 v]tically1 because ?is is s pla9 t he mu/ take x into acc\nt at e focus+4 ,he does n1 h[ev]1 accommodate himself to ! rev]sal f "r to left because ?is is ( no consequ5ce ord9>ily & is n notic$4 ,_m photograph]s1 :o h be5 accu/om$ to ! v]tical inv]sion1 /ill f9d !mselves confus$ :5 try+ to locate ! "r & left ( a view se5 ?r\gh ! l5s4 ,unless a special arrangem5t ( l5ses is provid$1 all images ca/ ^u scre5s ?r\gh small op5+s appe> inv]t$4 ,! reason = ?is c be se5 f ,figure #fb4 ,x is obvi\s t no o!r light c rea* ! bottom ( ! scre5 ?r\gh ! p9 hole ,o1 at ! left ( ! figure1 except t com+ f ! flame ( ! c&le2 also t no o!r light c rea* ! top ( ! scre5 except t reflect$ f ! bottom ( ! c&le at ! "r4 ,h5ce ! image ( ! c&le appe>s inv]t$4 ,illu/ration3 ,,figure #fb4 ,illu/ration3 ,,figure #fc4 ,a g5]al und]/&+ ( ! /ructure ( ! eye c be _h f ,figure #fc4 ,w indicates a wat]y sub/ance 9 ! front ( ! eye2 ,i is ! iris :i* has p[] to contract or exp& & ?us regulate ! quantity ( light admitt$ to ! eye2 ,p is ! pupil2 ,l is ! l5s2 & ,r is ! ret9a :i* connects ) ! optic n]ve & ! bra94 ,! l5s is made up ( sev]al p>ts hav+ diff]5t indexes ( refraction4 ,! :ole resembles an ord9>y convex l5s b has consid]able p[] ( adju/m5t4 ,:5 look+ at objects close by1 = in/ance1 ! pupil c (t5 be se5 to bulge out :i* is its me?od ( accommodat+ itself to objects close at h&4 ,to ! iris falls ! duty ( regulat+ ! quantity ( light :i* is to rea* ! ret9a4 ,if confront$ by a bright light1 x closes p>tially2 9 a dim light1 x op5s out wide4 ,:5 subject to a flick]+ light1 !re is a t5d5cy to foll[ ! flick]+s by rapid op5+ & clos+1 :i* causes pa94 ,if subject to flick]+s long en\gh1 h[ev]1 ! pa9 becomes some:at less1 probably because ! iris has come to re/ on an int]m$iate po9t4 ,an image =m$ ^u ! ret9a rema9s = "s "t1 ! "t v>y+ ) ! int5sity ( ! light4 ,v int5se impressions are suppos$ to la/ ab\t "o tw5ty-fif? ( a second2 mild] ones z long z "o-t5? ( a second4 ,?is t5d5cy to reta9 images is kn[n z ! p]si/5ce ( vision & c be notic$ 9 _m ways4 ,a tw5ty-five cycle alt]nat+ curr5t falls to z]o fifty times 9 "o second2 & fifty times 9 ea* second !re is a slight cool+ (f ( ! inc&esc5t filam5t4 ,yet ! v>iation 9 ! int5sity ( ! light is noticeable4 ,_m ( ! sleight-(-h& tricks dep5d ^u ?is p]si/5ce ( vision & ! projection ( mov+ pictures w\ld be impossible )\t x4 ,we are able to judge di/ance pr9cipally ?r\gh ! fact t we h two eyes4 ,if our eyes 7 immovable1 we %\ld see two images = e object4 ,b z !y are movable & z bo? normally po9t directly at ! object we are look+ at1 _! axes =m angles ) ea* o!r & 9 ?is way we are enabl$ to judge ! di/ance1 z well z o!r qualities ( objects4 ,:5 bo? eyes are c5t]$ ^u an object1 ! impressions receiv$ by ! bra9 f bo? s\rces are mix$1 & ! picture we become consci\s ( is a composite ( ! two images 9 ! eyes4 ,?is is v]ifi$ by ! fact t _m p]sons ) defective vision c see mu* m cle>ly ) "o eye ?an ) bo?4 ,!y are n able to focus bo? eyes ^u ! same po9t & ?us ! p]fectly cle> picture :i* may exi/ 9 "o eye is mix$ ) an unc]ta9 picture 9 ! o!r4 ,9 y\? normal eyes are able to adju/ !mselves to diff]5t int5sities ( light & diff]5t di/ances v rapidly4 ,?is p[] is l>gely curtail$ z age advances4 ,:]e a "y p]son c almo/ in/antly1 aft] gaz+ at "s di/ant object1 turn to a newspap] & read1 ! eyes ( a p]son ( advanc$ age g5]ally require consid]able "t be=e !y c adju/ !mselves 9 ! same way4 ,q frequ5tly1 h[ev]1 v old p rega9 _! p[]s ( vision & become able to d )\t ! glasses =m]ly us$4 ,all ( ! above facts %\ld be ?or\ghly und]/ood by ^? hav+ to d ) illum9ation us$ by a mix$ audi5ce4 ,light t may seem p]fectly satisfactory to "o may be entirely unsuitable = ano!r4 ,,*apt] ,x4 ,,reflection4 ,light may be reflect$ f opaque or transp>5t bodies su* z glass4 ,9 ! case ( transp>5t bodies1 ! reflect$ rays are n noticeable unless ! gr\nd beh9d ! reflect+ body is d>k4 ,if !re is mu* light beh9d a pane ( glass1 = in/ance1 ! pupil ( ! eye w be p>tially clos$ & n be able to see ! fa9t light :i* is reflect$4 ,z we gradually d>k5 ! space beh9d ! glass1 ! image beg9s to appe> m & m di/9ct1 p>tly f contra/ ) ! d>k backgr\nd & p>tly on acc\nt ( ! increas$ op5+ ( ! pupil4 ,?is c be readily notic$ if "s ev5+ out ( a dimly-light$ room we look at "s object j disc]nible4 ,if we !n turn on ! light sudd5ly1 ! object w at once disappe> b reflections w appe> 9 ! glass :]e !re 7 none be=e4 ,! reflections f cle> glass are mu* /rong] at an angle ?an :5 ! rays are ?r[n /raight back4 ,?is c be se5 by plac+ any object directly 9 front ( a pane ( glass ) a d>k backgr\nd4 ,if we place ! eye s z to receive only ^? rays :i* are reflect$ directly back1 we %all obta9 b a weak reflection4 ,if1 h[ev]1 we place ! object a little to "o side & /& close to ! glass1 we %all see ! object almo/ z pla9ly z 9 a regul> mirror4 ,a ray ( light is always reflect$ at exactly ! same angle at :i* x /rikes1 ! reflect+ body2 t is1 ! angle ( incid5ce is equal & opposite to ! angle ( reflection4 ,?is c be illu/rat$ by ,figure #fd4 ,if a mirror be atta*$ to ! po9t] 9 ! position %[n at an angle ( exactly n9ety degrees & a beam ( light be all[$ to ent] ?r\gh ! slit at ! top1 x w be reflect$ back exactly to ! spot at :i* x ent]$4 ,if we !n turn ! po9t] slightly1 we %all notice t ! reflection ( ! beam ( light moves twice z fa/ z ! po9t] &1 :5 ! po9t] occupies ! position indicat$ by brok5 l9es1 ! light w be reflect$ at "r angles to ! l9e along :i* x ent]s4 ,if ! mirror is turn$ /ill m1 ! same law w hold2 s t1 if ! mirror 7 turn$ ?r\gh an angle ( ne>ly n9ety degrees1 ! reflect$ beam ( light w\ld 9 ! same space ( "t make an angle ( ne>ly "o hundr$ eighty degrees4 ,illu/ration3 ,,figure #fd4 ,reflect$ light results 9 ! =mation ( images 9 mirrors & o!r reflect+ bodies &1 by be>+ 9 m9d ! law ( reflection giv5 above1 we c readily expla9 h[ ^! images are =m$ & ! mann] 9 :i* !y appe> to u4 ,illu/ration3 ,,figure #fe4 ,let ,n1 ,figure #fe be an object 9 front ( ! mirror4 ,! only rays t are reflect$ back to ! eye are ^? t /rike ! mirror at ! prop] angle4 ,all o!rs are wa/$ ) ref]5ce to ! p>ticul> position ( ! eye4 ,if ! eye & ! object reflect$ are equally di/ant f ! mirror1 we ne$ b draw a l9e at "r angles to ! mirror & half way betwe5 ! eye & ! object &1 f ^! two1 draw l9es to ! po9t at :i* ! p]p5dicul> l9e /rikes ! mirror4 ,! two l9es ?us drawn w give u ! pa? ( ! incid5t & ! reflect$ rays4 ,! image w appe> to lie 9 ! direction f :i* ! reflect$ ray comes & z f> beh9d ! mirror z ! object is 9 front ( x4 ,if ! eye & ! object to be reflect$ are n equally di/ant f ! mirror1 x is m difficult to f9d ! pa?s ( ! rays & x simplifies matt]s v mu* to use ! foll[+ con/ruction3 ,draw a l9e f ! object be=e ! mirror at "r angles to ! mirror & ext5d x beh9d ! mirror z f> z ! object is 9 front ( x4 ,f ?is po9t beh9d ! mirror1 draw ano!r l9e to ! eye4 ,by draw+ a ?ird l9e f ! object to ! po9t 9 ! mirror :]e ?is l9e1 f back ( ! mirror to ! eye1 crosses x1 we %all obta9 ! pa?s ( ! rays & ! position ( ! image 9 ! mirror4 ,! image w exi/ 9 ! mirror at ! po9t :]e ! reflect$ & incid5t rays meet b w h ! appe>ance ( ly+ "s di/ance beh9d ! mirror4 ,?is is illu/rat$ 9 ,figure #fe1 ,n be+ ! object reflect$ & ,m ! app>5t position ( ! image to ! eyes z locat$ 9 ! cut4 ,illu/ration3 ,,figure #ff4 ,illu/ration3 ,,figure #fg4 ,illu/ration3 ,,figure #fh4 ,9 ,figures #ff & #fg ! same con/ruction is us$ to %[ ! appe>ance ( arr[s z !y are reflect$ f a mirror to ! eye4 ,objects /&+ erect ov] horizontal mirrors or arrang$ at "r angles to mirrors & look$ at1 z 9 ,figure #fh1 always appe> inv]t$4 ,?is c be notic$ 9 quiet ponds ( cle> wat] :i* give reflections ( trees & o!r objects4 ,figure #fh %[s two arr[s1 "o horizontal1 ! o!r v]tical2 by ! con/ruction 9 ! figure "o appe>s inv]t$1 ! o!r n4 ,if ! arr[ 7 plac$ 9 ! position indicat$ by brok5 l9es1 ! eye w\ld see only ! butt4 ,if ! arr[ 7 plac$ a little ne>] ! horizontal1 x w\ld appe> 9 its natural position2 if a little m v]tical1 x w\ld appe> inv]t$ 9 ! mirror4 ,illu/ration3 ,,figure #fi4 ,all objects se5 9 mirrors are rev]s$ ) ref]5ce to "r & left4 ,a pocket on ! left side ( a p]son fac+ a mirror w appe> to be on ! "r side4 ,pr9t$ matt] held be=e a mirror w appe> j z x w\ld if se5 ?r\gh ! pap] f ! back side & w h to be read f "r to left4 ,illu/ration3 ,,figure #gj4 ,illu/ration3 ,,figure #ga4 ,illu/ration3 ,,figure #gb4 ,if an object be plac$ betwe5 two p>allel mirrors z ,b1 ,figure #fi1 !re w be a va/ numb] ( reflections visible at ! po9t ,d4 ,sev]al reflections ( ,b w come to ! eye 9 ! mann] indicat$ b !re w be a l>ge numb] ( additional reflections4 ,if ! mirrors are exactly p>allel & absolutely smoo?1 ! numb] ( reflections w\ld !oretically be inf9ite4 ,at ea* reflection1 h[ev]1 "s light is absorb$ & "s diffus$ s t _m ( ! reflections are n disc]nible4 ,two mirrors set opposite ea* o!r w also give _m reflections ( ea* o!r z indicat$ 9 ,figure #gj4 ,! images se5 9 p>allel mirrors all appe> arrang$ 9 /raight l9es on bo? sides1 z indicat$ 9 ,figure #fi4 ,if n[ "o ( ! mirrors be incl9$ s z to =m an angle ) ! o!r1 ! long l9e ( images w seem to become curv$ & f9ally lie 9 a circle4 ,if ! mirrors be plac$ at "r angles to ea* o!r1 z 9 ,figure #ga1 !re w be ?ree reflections ( ! object ,c visible & ^! w rea* ! eye by ! pa?s %[n4 ,if ! mirrors be plac$ at an angle ( sixty degrees to ea* o!r1 five images w appe> z %[n 9 ,figure #gb1 9 :i* ,a is ! object be+ reflect$4 ,! foll[+ tabulation %[s ! numb] ( images obta9able at diff]5t angles betwe5 ! mirrors4 -------------------------- ,angle betwe5 ,numb] ( mirrors images -------------------------- #ij degrees #c #gb degrees #d #fj degrees #e #de degrees #g #cj degrees #aa -------------------------- ,illu/ration3 ,,figure #gc4 ,in/ead ( be+ pla91 mirrors may be ei!r concave or convex4 ,a concave mirror is holl[$ out 9 con=mity ) a small section ( ! surface ( a sph]e4 ,if a piece ( glass be cut out ( a holl[ sph]e1 ! inn] side ( x w %[ ! surface ( a concave1 & ! out] side1 ! surface ( a convex mirror4 ,a section ( a concave mirror is %[n 9 ,figure #gc4 ,c is ! c5t] ( curvature & any l9e drawn f ! surface ( ! mirror to ?is c5t] is at "r angles1 or normal1 to ! curvature ( ! mirror4 ,a ray ( light emanat+ f ?is c5t] w be reflect$ /raight back to x4 ,if ! s\rce ( light be mov$ a little ne>] to ! mirror1 ! light reflect$ w be spread out m & come to a focus f>!r back f ! glass2 if x be mov$ f>!r back f ! glass1 ! rays w be focus$ ne>] ! mirror4 ,?us if a light be plac$ at ,a1 its rays w be focus$ at ,d & a light plac$ at ,d w focus at ,a4 ,?is c be se5 by ! l9es :i* repres5t ! rays ( light4 ,! two po9ts at :i* a s\rce ( light w ?us focus are kn[n z ! conjugate foci ( ! mirror4 ,if su* a mirror receives p>allel rays ( light1 !y w be reflect$ & come to a focus at a po9t midway betwe5 ! mirror & ! c5t] ( curvature4 ,?is po9t is kn[n z ! pr9cipal focus ( ! mirror1 & ! di/ance betwe5 x & ! mirror is call$ ! focal l5g? ( ! mirror4 ,a s\rce ( light plac$ at ?is po9t w ?r[ out p>allel rays f ! mirror4 ,if ! light be mov$ clos] to ! mirror1 ! reflect$ rays w spread out2 :ile if mov$ f>!r away1 ! light w come to a focus at "s di/ant po9t1 z %[n above4 ,figure #gd c be us$ to illu/rate ! mann] 9 :i* a concave mirror reflects ! light f an object plac$ be=e x4 ,f ! upp] po9t ( ! l>ge arr[1 rays ( light emanate 9 all directions4 ,all t /rike ! face ( ! mirror are ?r[n to a c]ta9 po9t :i* c be f\nd by trac+ out ! l9es1 us+ ! small arr[s z guides4 ,at ?is po9t w appe> ! image ( ! top ( ! arr[4 ,x w be not$ t x is inv]t$4 ,! rays f ! l[] "p ( ! arr[ are ( c\rse all reflect$ 9 ! same mann]4 ,illu/ration3 ,,figure #gd4 ,) mirrors ( ?is k9d1 ! position ( ! object ) ref]5ce to ! focal l5g? & c5t] ( curvature is ( great importance4 ,if ! object be plac$ 9 ! position %[n z ! image 9 ,figure #gd1 ! image w appe> z ?\gh x 7 9 place ( ! object2 x w be mu* enl>g$ & also inv]t$4 ,if ! object is plac$ betwe5 ! pr9cipal focus & ! mirror1 x w appe> to lie beh9d ! mirror z %[n 9 ,figure #ge4 ,9 ?is case x w n be inv]t$4 ,illu/ration3 ,,figure #ge4 ,:5 concave mirrors =m+ l>ge sections ( sph]es are us$1 ! rays reflect$ f ! out] edges w n all meet exactly at ! focal po9t4 ,!re w !n be a some:at fuzzy image =m$4 ,?is is illu/rat$ 9 ,figure #gf4 ,9 ord] to obta9 a p]fectly cle> & di/9ct image1 only ! c5tral "p ( concave mirrors %\ld be us$4 ,illu/ration3 ,,figure #gf4 ,convex mirrors are n mu* us$4 ,sometimes glass sph]es are set up to %[ m9iature reflections ( sc5]y2 convex mirrors are also f\nd 9 ! lobbies ( !at]s & 9 places ( amusem5t to amuse ! patrons ) ! c>icatures ( !mselves reflect$ 9 !m4 ,illu/ration3 ,,figure #gg4 ,all ( ! rays t /rike a convex mirror are reflect$ back 9 su* a mann] t !y seem to come f a common po9t beh9d ! mirror4 ,?is is %[n 9 ,figure #gg4 ,! c5t] ( curvature "h is beh9d ! mirror b ! pa?s ( ! v>i\s rays c be det]m9$ z be=e expla9$4 ,?us we %all f9d t e ray1 /rik+ ! mirror f a c]ta9 po9t1 is reflect$ back 9 a direction :i* gives x ! appe>ance ( com+ f a c]ta9 po9t beh9d ! mirror4 ,two su* po9ts are %[n 9 ,figure #gg4 ,illu/ration3 ,,figure #gh4 ,9 ,figure #gh we h drawn ! arr[ & ! image x w\ld produce 9 ! mirror4 ,if ! mirror =ms a section ( a sph]e1 ! object reflect$ w appe> r$uc$ 9 size 9 all directions4 ,if ! mirror =ms m]ely a section ( a cyl9d]1 a p]son /&+ 9 front ( x w appe> v mu* %ort] ?an natural b ( full wid? ?us pres5t+ a ridicul\s appe>ance4 ,convex & concave mirrors are (t5 comb9$ & if prop]ly set1 a p]son /&+ 9 front ( "o may see himself ei!r v mu* elongat$ or %ort5$4 ,,*apt] ,,xi4 ,,refraction4 ,if a /raight /ick or p5cil be plung$ into a vessel conta9+ wat]1 x w appe> to be b5t4 ,! reason = ?is appe>ance is giv5 9 detail 9 ,figure #gi4 ,! only light :i* c rea* ! eye f ! l[] extremity ( ! /ick mu/ rea* x by a pa? simil> to t ( ! b5d$ ray at ! left4 ,accord+ to ?is1 ! rays ( light leav+ ! bottom ( ! /ick at ,e b5d at ! wat]'s edge & meet ! eye z %[n4 ,to ! eye ! rays1 by :i* x sees ! end ( ! /ick1 appe> to come f ! direction ,f2 h5ce ! /ick is se5 crook$4 ,:5 a ray ( light passes f air into a d5s] m$ium su* z wat] or glass1 ! ray appe>s to be b5t some:at1 z illu/rat$ at ! left ( ,figure #gi4 ,?is b5d+ ( ! rays ( light is call$ refraction4 ,illu/ration3 ,,figure #gi4 ,! fact ( refraction c be fur!r v]ifi$ by plac+ an object ,g into an empty vessel 9 ! position %[n4 ,9 ?is position ! object is n visible to ! eye4 ,by sl[ly fill+ ! vessel ) wat]1 ! object w gradually appe> & w seem to lie 9 ! direction ( ! /raight dott$ l9e4 ,illu/ration3 ,,figure #hj4 ,! b5d+ or refraction ( light rays is gov]n$ by a law :i* holds 9 all cases4 ,! b5d+ diff]s ) diff]5t k9ds ( glass1 ) wat]1 ) oils1 or ev5 ) wat] mix$ ) *emicals2 b no matt] h[ mu* ! b5d+ may diff] ) diff]5t mat]ials1 = ea* mat]ial !re is a fix$ ratio betwe5 ! angle at :i* ! light ent]s & ! angle at :i* x cont9ues 9 ! mat]ial4 ,?is ratio is kn[n z ! index ( refraction4 ,= wat] x is ab\t #a4cc2 = glass ab\t #a4e2 = ! diamond ab\t #b4e2 etc4 ,?is c p]haps be mo/ easily expla9$ by ref]5ce to ,figure #hj4 ,"h ! top ( ! %ad$ space repres5ts ! surface ( ! glass at :i* ! light ent]s4 ,! l9e ,e is drawn at "r angles to ?is surface & ! v>i\s l9es1 meet+ 9 ! c5t] ( ! circle1 repres5t diff]5t rays ( light fall+ ^u ! glass at diff]5t angles4 ,! heavy l9e %[s ! ray ( light /rik+ ! glass & pass+ ?r\gh x4 ,simil>ly ea* l9e is drawn diff]5tly & ! nature ( ! l9es w act z a guide by :i* ! angle ( incid5ce ^u ! glass & ! angle at :i* ! rays cont9ue ?r\gh ! glass c be trac$4 ,:5 x is said t glass has an index ( refraction ( #a4e1 or #c_/b1 x means t ! s9e ( ! angle ( incid5ce is #a4e times z great z ! s9e ( ! angle ( refraction4 ,! s9e ( ! angle ( incid5ce is proportional to ! l5g? ( a l9e drawn f ! v]tical ,e to ! p]iph]y ( a circle1 outside ( ! glass or o!r sub/ance1 to :]e x meets ! ray2 & ! s9e ( ! angle ( refraction is proportional to ! l5g? ( a l9e drawn f ! same v]tical to ! p]iph]y ( ! same circle1 inside ( ! glass or o!r sub/ance1 :]e x meets ! ray4 ,9 ord] to lay out ! pa? ( a ray ?r\gh ! mat]ial1 its angle ( incid5ce be+ kn[n1 we may resort to ! con/ruction %[n 9 ,figure #hj4 ,draw ! incid5t ray at its prop] angle & ! v]tical l9e at "r angles to ! surface ( ! mat]ial4 ,f ! po9t ,a1 :]e ! ray ent]s ! circle1 & at "r angles to ! v]tical l9e1 draw ! l9e #a4 ,measure ! di/ance f ,a to ! v]tical l9e & divide x by ! index ( refraction2 & on a cont9uation ( ! l9e #a1 lay (f ! di/ance z f\nd4 ,f ! po9t s locat$1 draw a l9e p>allel to ! v]tical until x int]sects ! circle at ! bottom4 ,f ! po9t at :i* ! ray ent]s ! m$ium1 draw ano!r l9e to :]e ! la/ l9e drawn /rikes ! circle4 ,?is l9e w give ! direction 9 :i* ! ray is propagat$ 9 ! m$ium4 ,= glass1 ! index ( refraction is tak5 z #c_/b2 h5ce ! l9e #a mu/ conta9 ?ree p>ts1 :ile ! cont9uation conta9s two ( ! same l5g?4 ,^u leav+ ! m$ium1 ! ray is b5t back aga9 s t x cont9ues 9 a direction p>allel to t at :i* x ent]$1 z %[n 9 ,fig4 #ha2 & ?us ! case is rev]s$4 ,illu/ration3 ,,figure #ha4 ,illu/ration3 ,,figure #hb4 ,figure #hb is an illu/ration ( h[ bo? refract$ & reflect$ rays may be sev]al times reflect$4 ,if "o w hold a mat* close to a mirror1 look+ at x some:at f ! side1 !re w be visible six or eight di/9ct reflections ( x4 ,^! w be ( diff]5t int5sity4 ,if a s\rce ( light has its orig9 9 a m$ium d5s] ?an air1 x w be b5t z %[n 9 ,figure #hc4 ,9 su* a case "s ( ! rays d n leave ! m$ium at all b are reflect$ back into x1 z indicat$ at ! "r4 ,! heavy l9e indicates :at is commonly kn[n z ! critical angle4 ,?is angle v>ies ) diff]5t sub/ances & is ! angle at :i* ! refract$ ray ( light skims along ! surface & does n pass out4 ,all rays emitt$ at a l[] angle are return$ back into ! m$ium4 ,if an electric light 7 imm]s$ 9 wat]1 only ! rays ( light at ! left ( ! black l9e w\ld be visible to an eye outside4 ,illu/ration3 ,,figure #hc4 ,figure #hd is an illu/ration ( an equilat]al prism4 ,"h we h refraction on bo? surfaces & a light plac$ at ,a w\ld be se5 by ! eye z locat$ at ,b4 ,) prisms x is easily possible to locate a light s t x may be se5 9 two positions at ! same "t4 ,illu/ration3 ,,figure #hd4 ,figure #he %[s a d\ble convex l5s4 ,bo? sides ( x are segm5ts ( circles or sections ( a sph]e4 ,! c5t] ( curvature or ! radius ( "o side is at ,a & t ( ! o!r at ,b4 ,ea* m9ute p>ticle on ! surface ( su* a "p ( a sph]e may be look$ ^u z ! surface ( a prism1 ! incl9ation ( x be+ indicat$ by a l9e drawn at "r angles to a l9e pass+ f ! po9t ?r\gh ! c5t] ( curvature4 ,?is is illu/rat$ 9 ! figure by ! %ort heavy l9es at "r angles to ! brok5 l9es c5t]+ at ,a & ,b4 ,illu/ration3 ,,figure #he4 ,by us+ ! con/ruction expla9$ ) ,figure #hj & us+ = ! left-h& surface ! circle ( brok5 l9es & = ! surface at ,e ! circle ( solid l9es1 we f9d ! pa? ( ! ray com+ f ,c to cross ! pr9cipal optical axis at ,a4 ,a simil> con/ruction = a ray at ! l[] side ( ! l5s w\ld br+ x to ! same po9t & fur!rmore all p>allel rays w\ld focus at ?is po9t4 ,?is po9t is ?us kn[n z ! pr9cipal focus ( ! l5s1 & ! di/ance betwe5 ?is po9t & ! l5s is call$ ! focal l5g? ( ! l5s4 ,e l5s has two pr9cipal foci1 "o on ei!r side & at equal di/ances f ! l5s4 ,illu/ration3 ,,figure #hf4 ,illu/ration3 ,,figure #hg4 ,if1 in/ead ( subject+ ! l5s to p>allel rays1 we use rays emanat+ f a c5tral po9t on ! optical axis1 !y w come to a focus at "s diff]5t po9t on ! o!r side ( ! l5s1 z illu/rat$ 9 ,figure #hf4 ,if ! light be plac$ at ! pr9cipal focus ( ! l5s1 ! rays leav+ ! l5s w be p>allel4 ,if ! light be br\ght ne>] ! l5s1 ! rays leav+ x w spread out z %[n 9 ,figure #hg2 !y w leave ! l5s 9 a direction su* z to make ^u an obs]v] f 9 front ! impression t !y are com+ f ! po9t ,c beh9d ! l5s4 ,if ! light be plac$ beyond ! pr9cipal focus ( ! l5s1 ! rays w conv]ge to a po9t "s di/ance ahead ( x4 ,?is di/ance v>ies ) ! position ( ! light & ! two po9ts 7light on "o side & focus on ! o!r7 are kn[n z conjugate foci ( ! l5s4 ,illu/ration3 ,,figure #hh4 ,if an object be project$ ?r\gh a l5s z1 = in/ance1 ! arr[ at ! "r ( ,figure #hh1 x w appe> ^u a scre5 plac$ on ! opposite side1 b w be inv]t$4 ,! reason = ?is is t ! rays ( light /rik+ ! l5s f ! top ( ! arr[ w be refract$ z %[n1 cross ! focal po9t ,f1 & meet ^? :i* come f ! same po9t & pass ?r\gh ! c5t] ( ! l5s 9 a /raight l9e2 & ?us ! image ( ! arr[ head w appe> at ! bottom2 9 a simil> mann] ! image ( ! tail ( ! arr[ w appe> at ! top4 ,! flatt] ! l5s1 ! f>!r away w be ! po9t at :i* ! image is =m$4 ,illu/ration3 ,,figure #hi4 ,if su* a l5s be plac$ ov] an object1 ! light w come to ! eye z %[n 9 ,figure #hi4 ,! solid l9es %[ ! rays by :i* ! eye receives ! light & ! brok5 l9es %[ ! direction f :i* x appe>s to come4 ,?us we see ! object mu* enl>g$4 ,a l5s us$ 9 ?is mann] is spok5 ( z a read+ glass1 & ! great] ! curvature1 ! great] its magnify+ p[]4 ,illu/ration3 ,,figure #ij4 ,illu/ration3 ,,figure #ia4 ,9 ,figure #ij is illu/rat$ a d\ble concave l5s4 ,p>allel rays ent]+ ?is l5s are scatt]$ by x1 z %[n4 ,!re=e1 if su* a l5s be plac$ ov] an object1 ! light f ! extremity ( ! object w come to ! eye z indicat$ 9 ,figure #ia1 b w give ! appe>ance ( com+ along ! l9es ,h & ,i4 ,?us ! object w be se5 mu* r$uc$ 9 size4 ,su* l5ses are sometimes us$ by arti/s to br+ l&scapes to a r$uc$ size s t !y may be view$ z a :ole m easily4 ,illu/ration3 ,,figure #ib4 ,! g5]al =ms ( l5ses are %[n 9 ,figure #ib1 7a7 ,is a plano-convex l5s 7b7 ,is a d\ble convex l5s 7c7 ,is a convexo-concave l5s1 or convex m5iscus 7d7 ,is a plano-concave l5s 7e7 ,is a d\ble concave l5s 7f7 ,is a concavo-convex l5s1 or concave m5iscus4 ,,*apt] ,,xii4 ,,optical ,,in/rum5ts4 ,9 mo/ optical in/rum5ts1 l5ses are us$ = ! purpose ( ga!r+ a l>ge numb] ( rays ( light & alt]+ ! app>5t direction ( ! rays s t an enl>g$ picture may be pres5t$ to ! eye4 ,9 ord] to accompli% ?is1 x is necess>y t ! rays ( light be b5t or refract$4 ,?is refraction1 we h already se51 is always accompani$ by a disp]sion :i* causes ! light to be dissolv$ into its orig9al colors m or less4 ,?is has be5 illu/rat$ by means ( prisms4 ,illu/ration3 ,,figure #ic4 ,illu/ration3 ,,figure #id4 ,:]ev] a s+le l5s is us$1 ! light ar\nd ! edges ( ! illum9at$ space is always m or less color$1 v>y+ ) ! illum9ant us$4 ,su* color+ is mo/ noticeable along ! edges ( project$ pictures b x also exi/s1 ?\gh to a less noticeable degree1 ov] ! :ole field1 %[+ lea/ 9 ! c5t]4 ,! light :i* is ?us refract$ & disp]s$ by "o prism may be ga!r$ aga9 by ano!r1 z %[n 9 ,figure #ic1 b ! light rays aft] pass+ ?r\gh ! second prism w be exactly p>allel to ! ray /rik+ ! fir/4 ,! light com+ out ( ! second prism w appe> :ite b x w be impossible ei!r to enl>ge or dim9i% ! size ( a picture 9 ?is way2 h5ce l5ses1 correct$ to give :ite light 9 ?is mann]1 w\ld be ( no use4 ,=tunately x has be5 f\nd t1 ) diff]5t k9ds ( glass1 ! ratio ( refraction to disp]sion is diff]5t2 & by comb9+ two pieces ( glass ( diff]5t nature1 x is possible to recomb9e ! colors )\t caus+ ! em]g5t ray to become p>allel to ! incid5t ray4 ,consid]1 = in/ance1 ,figure #id 9 :i* we h drawn a prism made up ( two diff]5t k9ds ( glass4 ,if ! "r half 7 ( a glass hav+ ! same index ( refraction z ! left1 = ! r$ rays = in/ance1 ^! w\ld cont9ue ?r\gh bo? 9 a /raight l9e4 ,if ! disp]sion 7 less 9 ! "r half1 i4e41 if ! violet rays 7 refract$ less--suffici5tly less to cause !m to approa* ! r$--!y w\ld meet ! latt] at "s po9t outside ( ! prism & comb9e into :ite light aga91 ?us elim9at+ ! colors ord9>ily visible ?r\gh s+le glass l5ses4 ,illu/ration3 ,,figure #ie4 ,:5ev] x is necess>y to project especially good pictures ^u a scre51 l5ses correct$ 9 "s su* mann] z outl9$ above are always us$ & ! l5ses are (t5 comb9$ z %[n 9 ,figure #ie4 ,9 ?is figure1 ,r indicates ! l9e1 ?r\gh ! pr9cipal axis1 at :i* ! r$ rays refract$ by l5s #a alone w\ld /rike2 & ,v1 ! l9e :]e ! violet rays w\ld be project$4 ,! addition ( l5s #b br+s ! r$ & violet toge!r aga9 at ,w4 ,a comb9ation ( two su* l5ses1 plac$ ! prop] di/ance ap>t & ! surfaces prop]ly proportion$1 may be made to comb9e any two ( ! colors ( ! spectrum4 ,h5ce ev5 ) ^! correct$ l5ses !re is always "s color+ on ! scre5 al?\gh x is h>dly noticeable4 ,illu/ration3 ,,figure #if4 ,illu/ration3 ,,figure #ig4 ,illu/ration3 ,,figure #ih4 ,figures #if1 #ig1 & #ih are draw+s %[+ ! mann] 9 :i* objective l5ses are usually made up4 ,! types at ! "r & left are us$ = cam]a "w1 :ile ! "o %[n 9 ! c5t] is us$ mo/ly = mov+ picture & /]eopticon projection4 ,! end hav+ ! sep>ate l5ses is turn$ t[>ds ! light4 ,^? %[n 9 contact are glu$ toge!r by ! use ( ,canadian balsam4 ,illu/ration3 ,,figure #ii4 ,! optical sy/em ( ! ord9>y telescope is %[n 9 ,figure #ii4 ,light f ! di/ant object ,a is ga!r$ by ! l>ge l5s ,b & an image is =m$ z indicat$ by ! small arr[4 ,?is image acts z ! object to l5s ,c & is project$ to l5s ,d :]e ! rays ( light are /rongly refract$1 ent]+ ! eye by angles :i* cause an enl>g$ view ( ! object at ,e1 z indicat$4 ,!re mu/ ( c\rse be "s means by :i* ! l5ses may be adju/$ to ea* o!r = focus+4 ,illu/ration3 ,,figure #ajj4 ,! arrangem5t ( ! op]a glass 9 ,figure #ajj is q diff]5t f ! above because ( ! r$uc$ size ( ! in/rum5t & = ! reason t an erect picture is desir$1 :]eas ! telescope above gives an inv]t$ "o4 ,! pr9cipal diff]5ce betwe5 ! two is 9 ! eyepiece4 ,9 ! op]a glass ?is is a concave l5s :ile 9 ! o!r x is a convex l5s4 ,9 ?is case x is necess>y to h ! eye v close to ! l5s to cat* ! rays ( light4 ,! op]a glass1 z well z ! telescope1 mu/ be provid$ ) means ( v>y+ ! di/ance betwe5 ! l5ses accord+ to ! di/ance ( ! object view$1 = ! purpose ( focus+4 ,9 "s telescopes & also op]a glasses1 prisms are us$ = ! purpose ( obta9+ erect images4 ,figure #aja w %[ h[ ! rays ( light ent]+ a prism are reflect$ & ! image rev]s$ !reby4 ,illu/ration3 ,,figure #aja4 ,figure #ajb is an explanation ( ! reflect+ /]eoscope4 ,let ! black circles repres5t ! eyes ( ! obs]v] & let ,m repres5t two mirrors plac$ z %[n4 ,if two pictures tak5 by a /]eoscopic cam]a are plac$ z indicat$ by ! arr[s at ! "r & ! left1 !y w appe> sup]impos$ 9 ! position ( ! arr[ 9 ! re>4 ,illu/ration3 ,,figure #ajb4 ,illu/ration3 ,,figure #ajc4 ,! refract+ /]eoscope is ! "o mo/ly us$ & ! plan ( x is %[n 9 ,figure #ajc4 ,pictures = use ) /]eoscopes are tak5 by special cam]as provid$ ) two l5ses plac$ ab\t z f> ap>t z ! human eyes & m\nt$ toge!r4 ,/]eoscopic effects may1 h[ev]1 be produc$ ev5 )\t ?is precaution & x is possible to obta9 "s que] results by comb9+ c]ta9 pictures4 ,9 ! s-call$ 8,cam]a ,lucida01 prisms ( ! type %[n 9 ,figures #ajd & #aje are us$4 ,at ! left is a comb9ation l5s & reflect+ prism :i* gives an erect image1 & ,figure #aje is a prism also design$ to give erect images4 ,su* in/rum5ts are us$ = sket*+4 ,!y may be made to ?r[ an image ^u a small scre5 :]e its l9es may be trac$ out by ! arti/4 ,illu/ration3 ,,figure #ajd4 ,illu/ration3 ,,figure #aje4 ,! mo/ important optical in/rum5t ) :i* we h to deal is ! project+ arc lamp & its optical sy/em4 ,! passage ( light ?r\gh ?is sy/em ( l5ses is altoge!r diff]5t f t pass+ ?r\gh a cam]a l5s = in/ance4 ,9 a cam]a l5s ! picture is =m$ ^u ! gr\nd glass scre5 by ! light reflect$ f ! object4 ,f any s+le po9t ( ! object1 rays ( light /rike all p>ts ( ! l5s1 pass ?r\gh x1 & are recomb9$ or focus$ at "s po9t beh9d x4 ,"u ^! conditions1 focus c be obta9$ only at a c]ta9 di/ance beh9d ! l5s1 ?is di/ance v>y+ ) ! di/ance ( ! object ^: light is be+ receiv$ by ! l5s4 ,illu/ration3 ,,figure #ajf4 ,illu/ration3 ,,figure #ajg4 ,illu/ration3 ,,figure #ajh4 ,) our project+ l5s we h no reflect$ light leav+ ! object 9 all directions1 b in/ead we h rays ( light hav+ def9ite directions4 ,?is c be se5 f ,figure #ajf4 ,! light us$ mu/ come f a po9t s\rce1 ! small] & ! m int5se x is ! bett]4 ,?is light is ga!r$ by cond5s]s1 z %[n at ,c1 :i* are s arrang$ z to focus ! light 9 ! c5t] ( ! objective l5s ,d4 ,9 ! mov+-picture ma*9e ! light1 be=e rea*+ ! objective l5s1 is pass$ ?r\gh ! film z indicat$1 ! arr[s repres5t+ sections ( film4 ,! picture project$ 9 ?is mann] c be made to appe> ^u a scre5 9 front ( ! object l5ses at any di/ance1 b ! f>!r away x is1 ! l>g] x w be & ! less bright ! illum9ation ( x4 ,a picture project$ 9 ?is mann] is always inv]t$1 &1 9 ord] to h x appe> "r side up1 x mu/ be plac$ 9 position upside d[n4 ,figures #ajg & #ajh %[ arrangem5t ( l5ses frequ5tly us$ z cond5s]s4 ,,*apt] ,,xiii4 ,,optical ,,illusions4 ,illu/ration3 ,,figure #aji4 ,illu/ration3 ,,figure #aaj4 ,illu/ration3 ,,figure #aaa4 ,illu/ration3 ,,figure #aab4 ,! eye is easily deceiv$ & is also v inaccurate 9 its judgm5t4 ,9 ,figures #aji to #aaa1 all ( ! l9es are ( precisely ! same l5g?1 yet !y appe> to diff] consid]ably4 ,! reason = ?is error 9 ! e/imation ( objects is n kn[n4 ,x is especially noticeable ) su* objects z a high hat2 almo/ any "o w e/imate ! height ( a silk hat z mu* great] ?an x really is4 ,9 g5]al1 :ite objects also appe> to be mu* l>g] ?an black objects4 ,?is c be se5 by ! two inscrib$ squ>es "o black & ! o!r :ite 9 ,figure #aab2 bo? ( ^! are ( exactly ! same size4 ,probably ! fact t m light rea*es ! eye f a light-color$ object ?an f a d>k-color$ "o ( equal proportions causes ! impression ( great] size4 ,t ! m9d has ! p[] ( mix+ contradictory or conflict+ impressions made ^u x is prov$ by _m facts4 ,if a />1 ,figure #aac1 be p9n$ to ! c5t] ( a :eel & rapidly revolv$1 ! c5t] ( x w appe> jet black2 :ile ! out] portions1 made up ( ! po9ts & ! :ite backgr\nd1 w appe> grey :i* w gradually fade to a light] %ade f ! c5t] black spot outw>d4 ,illu/ration3 ,,figure #aac4 ,illu/ration3 ,,figure #aad4 ,if a c>d be provid$ ) a picture ( a bird on "o side & a r+ on ! o!r1 ,figure #aad1 & ?is be rapidly spun on "o corn]1 aft] ! mann] ( a top1 ! bird w appe> to be 9 ! c5t] ( ! r+4 ,?is effect is due to ! p]si/5ce ( vision2 an image =m$ ^u ! ret9a requires "s "t be=e x c be elim9at$ s t bo? images appe> toge!r4 ,?is p]si/5ce ( vision & ! p[] ( sugge/ion are made use ( 9 a well-kn[n act :i* consi/s ( app>5tly ?r[+ some?+1 = in/ance a gu9ea pig1 into ! air & caus+ x to vani%4 ,to p]=m ?is trick1 ! op]ator holds ! pig 9 8 h& & makes a few motions sugge/ive ( toss+ x into ! air4 ,!n1 ) a f9al m extreme motion on ! d[nw>d sw+ ( 8 h&1 he drops ! pig & swiftly moves 8 empty h& upw>d4 ,due to ! p]si/5ce ( vision1 ! audi5ce actually /ill sees ! pig & due to ! sugge/ion ( toss+ ! eyes look upw>d1 & ?us ! p]si/5ce ( vision & ! p[] ( sugge/ion create ! illusion4 ,illu/ration3 ,,figure #aae4 ,dissolv+ ,views ( ,liv+ ,pictures4--,?is act requires a l>ge glass plate ( good cle> quality arrang$ ^u ! /age1 z %[n 9 ,figure #aae4 ,"o ( ! poses is arrang$ z at ! black circle beh9d ! glass & :5 illum9at$ is se5 by ! audi5ce4 ,! o!r is arrang$ at "o side4 ,! light+ ( bo? is connect$ to ! same dimm]s 9 su* a mann] t :5 ! light ( "o is increas+1 t ( ! o!r is dim9i%+4 ,?us ! two figures are dissolv$ into "o ano!r4 ,! pa?s ( ! v>i\s rays ( light to diff]5t p>ts ( ! auditorium are %[n 9 ! draw+ & x is possible to procure p]fect regi/ry4 ,human ,figure ,float+ or ,p]=m+ 9 ,air4--,?is act is arrang$ by means ( a l>ge mirror plac$ ^u ! /age z %[n 9 ,figure #aaf4 ,9 ! pit out ( sight ( ! audi5ce is a revolv+ table drap$ 9 dull black & all ( ! pit is drap$ 9 ! same mann]4 ,a figure ly+ ^u ?is table dress$ 9 light clo!s w appe> erect 9 ! mirror z indicat$ by ! arr[4 ,if n[ ! table is revolv$1 ! figure w be se5 z turn+ ov] 9 ! mirror4 ,! figure ^u ! table may p]=m a numb] ( evolutions sugge/ive ( float+1 fly+1 etc4 ,! black clo? ( ! pit w reflect no light & only ! figure w be visible4 ,if a glass plate is us$ in/ead ( a mirror1 suitable sc5]y may be arrang$ back ( x4 ,! figure mu/ ( c\rse be brightly illum9at$4 ,by mov+ ! table ^u :i* ! figure re/s across ! pit1 ! figure w appe> to move along4 ,illu/ration3 ,,figure #aaf4 ,head ,susp5d$ 9 ,air4--,?is act is work$ out 9 bright light4 ,x requires a mirror ) a hole 9 ! c5t] ( x l>ge en\gh to admit ! head ( a p]son1 z %[n 9 ,figure #aag4 ,above ! mirror suitable decorations are provid$ :i* cause "o look+ at ! mirror to imag9e see+ ! back wall ( a room4 ,! ceil+ mu/ ( c\rse be kept out ( view z mu* z possible4 ,a p]son look+ on sees ! head & ! mirror gives him ! impression ( vacant space ab\t x4 ,! head mu/ be surr\nd$ by a coll> or drap]y ( "s k9d s t no reflection ( x w be visible4 ,illu/ration3 ,,figure #aag4 ,illu/ration3 ,,figure #aah4 ,magic ,cab9et4--,9 ?is act a p]son ent]s ! cab9et1 ,figure #aah4 ,! out] doors are clos$ = an in/ant & !n op5$4 ,! p]son has disappe>$6 ,! disappe>ance is br\ght ab\t by pull+ ! two mirrors1 arrang$ inside ( ! cab9et1 into ! position indicat$ by ! dott$ l9es4 ,:5 ! cab9et is op5 = inspection1 ^! are swung to ! side & are invisible4 ,! backs are ( ! same design z ! re/ ( ! int]ior cab9et4 ,:5 !y are pull$ toge!r & hide ! p]son beh9d !m1 !y reflect ! side walls ( ! cab9et & are n notic$4 ,if ! cab9et is well made & ! act skilfully p]=m$1 ! out] doors may ev5 be omitt$4 ,head ,re/+ on ,table4--,= ?is act a hole l>ge en\gh to all[ a p]son's head to project ?r\gh is cut 9 ! top ( a table1 ,figure #aai4 ,?is table has only two legs & is fitt$ up ) mirrors1 z indicat$ by %ad+4 ,! reflection ( ! two legs 9 ! mirror causes ! obs]v] to see f\r & imag9e t ! space bel[ ! table is vacant4 ,illu/ration3 ,,figure #aai4 ,multiplication ( ,images4--,if ?ree l>ge mirrors be arrang$ 9 ! =m ( an equilat]al triangle1 z indicat$ 9 ,figure #abj1 a p]son /&+ 9 ! c5t] w see 8 image reflect$ s _m times t he w receive ! impression ( be+ 9 ! mid/ ( a cr[d4 ,he w see ! reflections ( reflections repeat$ until by absorption s mu* light is lo/ t !y f9ally become invisible4 ,illu/ration3 ,,figure #abj4 ,illu/ration3 ,,figure #aba4 ,trick ,mirror4--,r />tl+ effects c be produc$ by a ?9ly coat$ mirror ,a1 ,figure #aba1 beh9d :i* an electric light is arrang$ s t x may be easily turn$ on4 ,! space beh9d ! mirror be+ d>k1 no "o suspects t x is any?+ b a common look+ glass4 ,x is1 h[ev]1 q transp>5t :5 ! light beh9d x is turn$ on4 ,! p]son 9 front view+ himself may ?us sudd5ly be br\ght to see any?+ t is beh9d ! mirror4 ,if ano!r set ( mirrors is arrang$1 z %[n by %ad$ l9es1 ! p]son 9 front ( ! mirror may sudd5ly be made to see a head float+ 9 ! air 9 front ( him4 ,illu/ration3 ,,figure #abb4 ,! mann] 9 :i* "o c see ?r\gh a brick is illu/rat$ 9 ,figure #abb4 ,f\r mirrors reflect ! light ar\nd x4 ,if ! mirrors are prop]ly arrang$1 ! p]son w imag9e he is look+ ?r\gh ! brick4 ,illu/ration3 ,,figure #abc4 ,! face ( a p]son may be ?r[n ^u a scre5 among cl\ds or o!r pictures 9 ! mann] %[n 9 ,figure #abc4 ,! face occupies ! space m>k$ by a half circle & two arc lamps ) cond5s]s are tra9$ ^u x at v close range4 ,! face itself acts z a reflector project+ itself ?r\gh ! object l5s 9 ! c5t]4 ,?is act is v try+ on ! p]son ^: face is reflect$4 ,at a c]ta9 di/ance f a concave mirror1 an object w be se5 inv]t$4 ,if ! mirror be br\ght clos]1 ! image w gradually g out ( focus &1 by br++ ! mirror /ill clos]1 x w gradually come into focus aga9 b ?is "t erect4 ,prop]ly arrang$ su* a mirror c be made to give weird effects1 = in/ance a skeleton1 ru%+ at ! obs]v]2 & ! image w appe> to /ep out ( ! mirror4 ,,*apt] ,,xiv4 ,,!at] ,,build+s4 ,g5]al ,requirem5ts4--,9 mo/ cities x is requir$ t !at]s be built 9 locations :i* give free space = exits on two or m sides4 ,a common requirem5t is t two sides adjo9 public /reets or alleys & "o or bo? ! o!r sides be provid$ ) an op5 c\rt all[+ space = fire escapes & connections to /reet or alley4 ,! build+s are also1 z a rule1 requir$ to be ( firepro( con/ruction & divid$ practically into two p>ts by /rong fire walls2 "o ( ^! p>ts be+ ! auditorium1 t portion ( ! build+ us$ by ! public1 & ! o!r1 ! /age & its belong+s4 ,! ma9 fire haz>d ( c\rse is on ! /age & e possible precaution %\ld be tak51 fir/ to keep a fire f />t+1 & second1 to keep x1 %\ld x />t1 f communicat+ to ! auditorium4 ,9 ord] to protect ! audi5ce 9 case a fire />ts do+ damage on ! /age1 a /eel & asbe/os firepro( curta9 is g5]ally provid$1 l>ge en\gh to cov] ! :ole prosc5ium op5+ & equipp$ ) ! necess>y app>atus to l[] x in/antly 9 case ( necessity4 ,9 ord] to keep ?is curta9 9 fir/-class work+ ord] x is l[]$ at ! end ( e act & 9 ! case ( cont9u\s vaudeville p]=mances1 :i* are n divid$ into acts1 at lea/ once or twice dur+ ea* p]=mance4 ,?is curta9 mu/ be /rong en\gh to )/& ! /ra9 ( air pressure :i* w\ld exi/ 9 case ( a fire rag+ beh9d x4 ,?is /ra91 :5 "o consid]s ! quantity ( oil-pa9t$ sc5]y c>ri$ by _m ( ! l>ge %[s1 is apt to be consid]able1 9 case ( fire4 ,9 ord] fur!r to protect ! audi5ce1 a l>ge v5t flue is requir$ above ! /age4 ,! purpose ( ?is v5t is to c>ry (f ! smoke & gases4 ,! ,*icago law requires ! v5t to be equal 9 area to "o-tw5tie? ( ! area ( ! /age & to ext5d fifte5 feet above ! highe/ po9t ( ! ro(4 ,! haz>d to ! audi5ce is n s mu* t ( ! actual fire1 z ( ! rapid consumption ( oxyg5 by ! flames4 ,?is causes /rangl+4 ,9 ! case ( ! ,iroquois ,!at] fire ! dea? ( _m 0 due almo/ entirely to ?is cause4 ,! flames spread+ rapidly consum$ all ( ! oxyg5 9 ! tightly clos$ !at]2 at ! same "t ! smoke & gases 7 spread+ & hundr$s ( ! audi5ce inhal$ ?is heat$ & vitiat$ air ) almo/ in/antly fatal results4 ,z a fur!r precaution aga9/ fire1 x is n[ requir$ 9 all l>ge cities1 t all sc5]y be firepro($ to su* an ext5t t x w n c>ry fire4 ,! usual te/ = ?is is1 to hold a mat* to a "p ( ! clo? long en\gh to burn a hole ?r\gh x4 ,! fire mu/ g out z soon z ! mat* is )drawn4 ,! foll[+ are extracts f ! ,*icago ord9ances gov]n+ !at]s ( ! l>g] class3 ,! build+ mu/ be ( firepro( con/ruction4 ,x mu/ adjo9 two public highways "o ( :i* may be an alley4 ,!re mu/ be an op5 space on bo? sides ( ! audi5ce room & 9 front4 ,all balconies1 gall]ies1 ma9 floor1 & /age mu/ connect ) ?is op5 space by means ( doors or fire escapes4 ,!re mu/ be an op5+ into ?is free space also f bo? sides ( /age4 ,! floor level ( ! highe/ bank ( seats on ! ma9 floor %all n be m ?an ?ree feet above ! sidewalk level & ! l[e/ bank ( seats n m ?an eight feet bel[ ?is level4 ,all /airways mu/ h a wid? ( tw5ty in*es = ea* "o hundr$ seats 9 ! room1 b no /airway %all be less ?an f\r feet 9 wid?4 ,an iron /airway mu/ lead f ! /age to ! fly floor1 rigg+ l(t1 & out onto ! ro(4 ,all op5+s lead+ f ! /age to ! outside mu/ be ve/ibul$4 ,above ! /age !re mu/ be a v5tilat+ flue :i* mu/ ext5d fifte5 feet above ! highe/ po9t ( ! ro( & mu/ equal 9 area "o-tw5tie? ( ! area ( ! /age4 ,no seat mu/ be less ?an tw5ty in*es wide & ?irty-f\r in*es f back to back4 ,e aisle mu/ lead directly to an exit4 ,betwe5 ! /age & ! auditorium !re mu/ be a wall ( masonry & all op5+s 9 ?is wall mu/ be equipp$ ) self-clos+ doors4 ,!re mu/ be a /eel curta9 provid$ to close ! ma9 /age op5+ & ! l[]+ ( ?is curta9 mu/ be controll$ at two diff]5t places4 ,! use ( wood is all[$ only = ! /age floor & ?is mu/ be at lea/ two & ?ree-f\r?s in*es ?ick4 ,automatic spr9kl]s mu/ be provid$ 9 pa9t room1 /or]oom1 prop]ty room1 sc5e /orage room1 c>p5t] %op1 & dress+ rooms4 ,a special fire al>m sy/em mu/ be provid$ on ! /age4 ,all sc5]y mu/ be treat$ ) a suitable firepro(+ comp\nd4 ,all p>ts ( ! build+ us$ by ! audi5ce mu/ be equipp$ ) two sep>ate light+ sy/ems1 "o ( :i* is kn[n z ! 8,em]g5cy ,light+0 & mu/ be kept light$ at all times :ile ! audi5ce is 9 ! build+4 ,a suitable supply ( axes1 pike poles1 & fire ext+ui%]s mu/ be kept on h&4 ,!re mu/ be regul> drills ( employes on ! use ( ^! appliances & 9 ! op]ations ( doors & v5ts4 ,all doors mu/ sw+ to ! outside4 ,illu/ration3 ,,figure #abd4 ,! ,/age4--,figure #abd is a floor plan ( a typical /age1 %[+ ! or*e/ra pit ,o1 foot lights ,f1 /eel curta9 ,c1 swit*bo>d ,s1 /age pockets ,q1 prosc5ium side lights ,p1 & g5]al arrangem5t ( sc5]y4 ,! foot lights are n always curv$ b x seems advantage\s to arrange !m 9 ?is way4 ,! r[s ( seats are ( necessity curv$ s z to face ea* patron squ>ely t[>d ! /age4 ,if !n ! /age & foot lights are curv$ 9 ! same way1 ! actors w be able to come t mu* clos] to ! audi5ce & c ?us make !mselves m easily he>d4 ,! curv+ ( ! foot lights w h ! fur!r advantage ( illum9at+ ! sides ( an actor m ?an w\ld be ! case if !y 7 laid out 9 a /raight l9e4 ,at ea* side ( ! /eel curta9 are ! prosc5ium side lights4 ,9 "s cases ^! lights are arrang$ on ! audi5ce side ( ! curta91 ! object be+ to arrange !m z f> 9 front ( ! /age z possible4 ,! location ( ^! lights is awkw>d & x is difficult to get light f !m 9 a useful direction4 ,9 mo/ !at]s ! swit*bo>d is locat$ on ! "r-h& side ( ! /age1 fac+ ! audi5ce4 ,?is is ! side f :i* ! /age manag] pref]s to "w & ! op]at+ electrician %\ld be close to him4 ,9 mo/ well-arrang$ !at]s1 ! swit*bo>d is rais$ above ! /age level s t x may n ob/ruct ! exits ( ! actors4 ,:]e practicable1 ! bo>d %\ld be let into ! prosc5ium wall s z to all[ ! op]ator to /& z close to ! prosc5ium op5+ z possible4 ,he %\ld h a full view ( ! /age at all times1 s9ce _m ( 8 cues are giv5 by movem5ts ( ! actors4 ,! /age pockets are laid out f> en\gh f ! c5t] ( ! /age to insure _! be+ always beh9d ! sc5]y4 ,if !y are br\ght 9 too close1 x is possible t1 9 a panorama sett+1 = in/ance1 !y w\ld be visible to ! audi5ce4 ,doors lead+ f ! /age to ! outside are always ve/ibul$ 9 good h\ses4 ,! ve/ibule prev5ts ! w9d f bl[+ ! drap]y ab\t unduly & also %ields ! actors f unpleasant drafts4 ,dress+ rooms are arrang$ :]ev] ! conditions ( ! build+ all[ suitable space4 ,_m ( !m are "u ! /age & o!rs are arrang$ on "o or bo? sides ( ! /age1 sometimes v high up4 ,a view ( ! /age look+ f ! re> is %[n 9 ,figure #abe4 ,?is figure %[s ! v5t1 ! me?od ( bord] light susp5sion1 bridges = support ( arc lamps or o!r s\rces ( illum9ation1 ! fly floor1 & ! rigg+ l(t1 or 8grid04 ,! rigg+ l(t is g5]ally con/ruct$ entirely ( iron slats ) op5 spaces betwe5 !m4 ,?is is necess>y to insure v5tilation 9 case ( fire4 ,illu/ration3 ,,figure #abe4 ,9 mo/ !at]s ! height f /age to ceil+ is ab\t sev5ty feet or m4 ,! height mu/ be great en\gh to all[ ! sc5]y to be hoi/$ out ( sight above ! prosc5ium op5+4 ,!re mu/ also be suffici5t space above ! rigg+ l(t to all[ m5 to walk ab\t /raight5+ out ropes1 etc4 ,! total height %\ld1 !re=e1 be ne>ly two & "o-half times t ( ! prosc5ium op5+4 ,illu/ration3 ,,figure #abf4 ,z a rule no op5+s ( any k9d are arrang$ 9 any ( ! enclos+ walls ( ! /age1 except ^? t are necess>y z entrances4 ,9 h\ses :i* are likely to orig9ate %[s1 a pa9t bridge is g5]ally provid$ along ! back wall4 ,illu/ration3 ,,figure #abg4 ,mov+-,picture ,!at]4--,figure #abf is a plan ( a typical small mov+-picture !at]4 ,a spaci\s lobby is an important adjunct to any su* !at] & ?is space is (t5 z valuable z ! seat+ space inside4 ,x af=ds %elt] to ^? :o _c be seat$ at ! mom5t4 ,x is especially conv5i5t 9 localities :]e race suicide is n yet v noticeable & :]e x =ms a repository = _m baby c>riages4 ,a view %[+ ! location ( a picture-ma*9e boo? is giv5 9 ,figure #abg4 ,?is is ! arrangem5t mo/ 9 use al?\gh !re are localities :]e x is requir$ t ! op]at+ room be at ! end ( ! !at] opposite ! ma9 entrance1 ! object be+ to avoid ! necessity ( ! audi5ce pass+ "u ! fire to ! outside 9 case a fire %\ld occur 9 ! op]at+ room4 ,?is plan has s _m disadvantages t x is nev] foll[$ except :]e ! law requires x4 ,if a prop]ly arrang$ op]at+ room is provid$1 !re is no necessity :atev] = x4 ,illu/ration3 ,,figure #abh4 ,! *ief use ( ,figure #abg is to illu/rate ! importance ( adju/+ ! height at :i* ! picture is ?r[n ^u ! curta9 to ! pit* ( ! floor4 ,! curv$ l9es 9 ! upp] "p ( ! picture indicate ! floor conditions :i* w\ld give ea* seat ! same cle>ance ov]-!-"o-9-front-(-x to a view at ! bottom ( ! picture4 ,! upp] l9e %[s ! bottom ( ! picture1 level ) highe/ seat1 ! o!r ) ! same po9t some:at bel[ x4 ,illu/ration3 ,,figure #abi4 ,figures #abh & #abi %[ ! plan & ! elevation ( a l>ge op]at+ room4 ,e op]at+ room %\ld be ( ample size to all[ ! op]ator to walk on all sides ( ! ma*9e4 ,x %\ld be /rictly firepro(1 well-v5tilat$1 & provid$ ) a door giv+ easy exit to a floor outside1 level ) ! floor ( ! room4 ,9 altoge!r too _m rooms ! only means ( gett+ 9 or out is by a ladd] :i* leads directly into ! room ?r\gh a small trap door4 ,su* an arrangem5t is extremely dang]\s 9 case ( fire4 ,! fumes ( burn+ film are poison\s if inhal$ & spread v fa/4 ,if two m5 %\ld happ5 to be 9 su* a room at ! "t ! film is ignit$1 x is likely t !y w\ld w$ge ea* o!r into ! n>r[ op5+ & bo? p]i%4 ,! door to ! op]at+ room %\ld op5 outw>d & be self-clos+4 ,all op5+s 9 ! op]at+ room mu/ be fitt$ ) firepro( %utt]s by :i* !y c be in/antly clos$ 9 case ( fire4 ,!re %\ld also be suitable v5tilation to ! outside to c>ry (f all smoke f burn+ film4 ,! ,scre54--,! scre5 ^u :i* ! picture is project$ %\ld be a cle> :ite b ( a dull f9i%4 ,all gl>e %\ld be avoid$ & :]ev] !re is a poli%$ surface1 ?is gl>e is always conspicu\s4 ,!re are a numb] ( pat5t or special makes ( scre5s on ! m>ket1 b x is n ! purpose at ?is "t to discuss any ( !m4 ,x w be suffici5t to po9t out "s ( ! simpl] me?ods by :i* scre5s may be made4 ,a simple pla/] wall is (t5 us$ & is v s]viceable1 b x mu/ n be poli%$ & mu/ be coat$ 9 "s way to all[ ( wa%+ (f occasionally4 ,p]haps1 all ?+s consid]$1 a musl9 scre5 is ! be/ ( all4 ,su* a scre51 if well /ret*$1 gives a good flat surface entirely )\t gl>e & has ! fur!r advantage t x c easily be tak5 d[n & laund]$ z (t5 z necess>y4 ,x is be/ to provide duplicate sets s t !re may be "o = use :ile ! o!r is 9 ! wa%4 ,! only real objection to a musl9 scre5 is ! loss ( light :i* x entails4 ,x is n only a poor reflector ( light1 b x all[s mu* ( ! light to pass ?r\gh x4 ,) _m su* scre5s1 ! picture is z well visible beh9d ! scre5 z x is 9 front ( x4 ,?is indicates a great loss ( light & x is to prev5t ?is loss ( light t ! o!r =ms ( scre5s h be5 devis$4 ,! mo/ noticeable ( ^! is ! mirror scre51 :i* is a mirror ( gr\nd glass4 ,x is v economical 9 light b exp5sive 9 fir/ co/ & h>d to keep clean4 ,x mu/ be wa%$ q frequ5tly & c>eless m5 are apt to use too mu* wat] & get "s ( x on ! back :]e x w soon beg9 to loos5 ! silv] coat+ & ru9 ! mirror4 ,! scre5 %\ld be surr\nd$ s t no o!r light except t com+ f ! picture c rea* ! audi5ce4 ,to ?is end !re %\ld be a black frame ar\nd x & ?is black frame mu/ also be a dull black & )\t gl>e4 ,velvet drap]y is ! v be/ ?+ t c be provid$ & %\ld be br\ght 9 s close f all sides t no :ite rim ar\nd ! picture w be visible1 z su* a :ite rim w\ld detract greatly f ! illum9ation ( ! picture4 ,! decorations ar\nd ! prosc5ium %\ld pref]ably be ( a d>k color & kept dull1 especially 9 cities :]e x is necess>y to ma9ta9 em]g5cy illum9ation4 ,if ! front is light 9 color1 !re w be consid]able reflection :i* w detract f ! picture & require a high] illum9ation ( x4 ,:]ev] !re is an opportunity to d s1 ! scre5 %\ld be set well away f ! ne>e/ r[ ( seats4 ,?is w n affect ! view ( ^? 9 ! re>1 & x w v mu* improve ! view ( ^? 9 front4 ,x mu/ ( c\rse be se5 to t a cle> view f bo? sides is possible4 ,,*apt] ,,xv4 ,,op]at+ ,,room ,,equipm5t4 ,con/ruction & ,v5tilation4--,! op]at+ room %\ld be built ( firepro( mat]ial1 su* z cem5t1 brick1 or tile4 ,if x is ( wood1 x may be made ne>ly firepro( by l9+ ! inside ) heavy %eet iron4 ,x w be well if asbe/os is plac$ betwe5 ! %eet iron & ! wood :i* x cov]s4 ,all woodwork1 :e!r w9d[ frames1 doors1 or %elv+ %\ld be ?us l9$4 ,x may be tak5 z practically c]ta9 t soon] or lat] "o or m reels ( film w be burn$ 9 ! room & e precaution %\ld be tak5 to prev5t ! fire f spread+4 ,if ?is is done !re w probably be no s]i\s results1 = 9 ! pa/ !re h be5 s _m film fires :i* h be5 successfully conf9$ to ! op]at+ room t audi5ces h become pretty well accu/om$ to !m4 ,if all op]at+ rooms are /rongly built & ( ample dim5sions1 ) all op5+s z small z practicable1 x w help to inspire confid5ce 9 ! audi5ce & !re w be b little likelihood ( a panic4 ,! *ief dang] is to ! op]ator4 ,x is true t he is g5]ally to blame1 b x is n always possible ev5 ) ! utmo/ c>e to prev5t a fire4 ,above all ! op]ator %\ld be giv5 e possible *ance to get away 9 case ( fire4 ,an op]ator :o feels t he c get away at ! la/ mom5t is f> m likely to /ay & fight a fire ?an "o :o is p5n$ up 9 a coop f :i* x is difficult to get out rapidly4 ,!re are 9 exi/5ce1 at ! pres5t "t1 op]at+ rooms :]e x is necess>y to crawl on h&s & knees "s twelve or fifte5 feet to get f ! ma*9e to ! exit1 & :]e ! exit is by means ( a trap door at ! head ( a ladd]4 ,su* op]at+ rooms are an abom9ation & no self respect+ op]ator w\ld "w 9 "o ( !m4 ,! entrance & exit f ! boo? %\ld be by means ( a door at ! "r h& or crank side ( ! ma*9e4 ,! door %\ld be self clos+ & %\ld op5 into a space hav+ a floor level ) ! floor ( ! op]at+ room4 ,! door %\ld pref]ably be kept clos$ b if ! provision illu/rat$ 9 ,figure #abh is made !re c be no s]i\s objection to leav+ ! door op5 = v5tilation4 ,a ?9 b> ( iron is fa/5$ to ! door by a screw eye & is us$ to block ! door op54 ,a p]son ru%+ out w naturally knock ?is away & ! door w close4 ,! door c\ld also be arrang$ to be held op5 by means ( ! /r+s1 to be describ$ lat]1 :i* hold ! %utt]s 9 place4 ,! v5tilation ( ! op]at+ room %\ld be by means ( a firepro( duct lead+ to ! out] air4 ,?is flue %\ld pref]ably ext5d above ! highe/ po9t ( ! ro( & %\ld be ( good size4 ,! smoke f burn+ film is heavy & does n rise v fa/ b x is g5]at$ ) extreme rapidity4 ,film burns at a temp]ature ( #bhd degrees ,fahr5heit4 ,if x is incas$ 9 a tank & fire communicates ) x1 ! :ole body ( ! film w be rais$ to ?is temp]ature 9 a v %ort "t & w burn ) ! rapidity ( an explosion4 ,9 ! magaz9es1 :i* are 9 g5]al use 9 ! new] h\ses1 ! combu/ion w be sl[] b nev]!less w take n m ?an ab\t "o m9ute4 ,x has (t5 be5 sugge/$ t a motor be provid$ 9 ! v5tilat+ flue1 ?is motor to be kept runn+ dur+ ! "t ! ma*9e is 9 op]ation4 ,?is w\ld no d\bt help cle> away all smoke v quickly b !re is no assurance t x w be runn+ at ! "t :5 x is mo/ ne$$4 ,a simple way to help out ! v5tilation )\t ! exp5se & noise ( a motor1 w\ld be to arrange ! v5tilat+ flue directly above ! arc lamps s t heat ris+ f ^! w\ld cause a draft4 ,?is c be fur!r help$ out by locat+ all resi/ances 9 ?is flue4 ,!y w !n be out ( ! way 9 a safe place & assi/ 9 v5tilat+ ! room4 ,! v5tilat+ flue w ne$ to be fitt$ ) a damp] = use 9 cold wea!r4 ,?is damp] %\ld be arrang$ to op5 by gravity & be held clos$ by a /r+ connect$ to ! %utt] /r+s s t ! damp] may op5 :5 ! %utt]s close4 ,! floor ( ! op]at+ room is a v important "p ( x4 ,x %\ld1 above all1 be extremely rigid s t ! ma*9e may be fa/5$ solid & ?us obviate any vibration :i* w cause movem5t ( ! picture4 ,all floors t are con/ruct$ ( wood are some:at ela/ic & aid ?is vibration4 ,movem5t ( ! picture is especially noticeable & annoy+ to ^? compell$ to sit close to x4 ,floors mu/ fur!rmore be l9$ ) firepro( mat]ial & ! only mat]ial us$ is %eet iron :i*1 ^u ! floor1 is v noisy & c h>dly be nail$ suffici5tly to elim9ate ! noise4 ,a metal floor l9+ has ! fur!r disadvantage ( af=d+ a good 8gr\nd10 s t any "o /&+ ^u x & t\*+ a live "p ( ! lamp is liable to receive a sev]e electrical %ock4 ,x w also soon we> ?r\gh1 make pockets to cat* dirt1 & all[ a fire to communicate ) ! woodwork b5ea? x4 ,! be/ floor mat]ial is cem5t1 b ?is1 :5 wet1 also becomes a fairly good conductor & %ocks may easily be obta9$ :ile /&+ ^u x4 ,!re is no reason1 h[ev]1 :y x %\ld ev] be wet 9 an op]at+ room & x is !re=e advisable to use cem5t4 ,! floor ( ! op]at+ room %\ld be kept cle> z f> z possible4 ,c>eless op]ators (t5 all[ _! take-up magaz9es to become d]ang$ & :5 !y fail to "w1 all[ ! film to run on ! floor4 ,a ?\s& feet ( film scatt]$ loosely ab\t occupies consid]able space & is v likely to become badly tangl$ 9 case !re is any?+ on ! floor = x to tangle )4 ,! writ] has witness$ cases :]e x 0 necess>y to take "s ( ! film outside ( ! boo? 9 ord] to get x /raight5$ out4 ,any op]ator :o has be5 9 a simil> pr$icam5t w appreciate ! advantage ( hav+ e possible ob/acle to a spe$y re-adju/m5t remov$4 ,above all1 resi/ances & o!r s\rces ( heat %\ld be kept (f ! floor4 ,e mov+-picture ma*9e requires at lea/ two op5+s2 "o ?r\gh :i* ! picture is project$1 :i* ne$ n be v l>ge2 ano!r ?r\gh :i* ! op]ator mu/ view 8 picture1 & ?is mu/ be l>ge en\gh to all[ him to sit 9 com=t :ile wat*+ ! picture4 ,9 "s op]at+ rooms ! op5+ ?r\gh :i* ! picture is project$ is clos$ by a metal funnel :i* cov]s ! op5+ & ext5ds back enclos+ ! front ( ! project+ l5s4 ,?is arrangem5t is v simple 9 ! case ( ma*9es 9 :i* ! revolv+ %utt] is beh9d ! l5s4 ,) _m ma*9es1 h[ev]1 ?is %utt] works 9 front ( ! l5s & ! funnel w\ld h to be ext5d$ s z to enclose ! revolv+ %utt]4 ,!re is no reason :y /rong cle> glass c\ld n be us$ 9 ! op]ator's peep hole4 ,?is w\ld ( c\rse int]f]e slightly ) ! cle>ness ( 8 vision = focus+1 b e op]ator %\ld be provid$ ) an op]a glass = ?is purpose anyway1 s t ?is objection w\ld be easily ov]come4 ,! same consid]ations :i* apply to motion-picture ma*9es also applies to /]eopticon lamps4 ,9 ! m pret5ti\s h\ses a spot light is g5]ally ma9ta9$4 ,?is is = ! purpose ( illum9at+ vaudeville p]=m]s4 ,! op5+1 provid$ = ?is lamp1 mu/ be l>ge en\gh to all[ ! light to foll[ an actor ab\t ! /age1 & glass _c well be us$ 9 x4 ,! be/ color = ! op]at+ room is gre5 b x mu/ be a dull d>k gre54 ,e ve/ige ( light ma9ta9$ 9 ! room helps dull ! vision ( ! op]ator to ! light ^u ! scre54 ,!re is1 fur!rmore1 mu* light reflect$ f ! film :]e ! light /rikes x & x is unavoidable t ! op]ator %\ld be bo!r$ by ?is at times4 ,all o!r light %\ld be kept away f 8 eyes :ile ! picture is runn+4 ,all ( ! op5+s 9 ! room mu/ be equipp$ ) fire %utt]s4 ,^! are g5]ally made ( heavy iron & are arrang$ s t1 if necess>y1 !y c be in/antly releas$ & made to close all ! op5+s1 ?us prev5t+ ! escape ( fire & smoke into ! auditorium4 ,illu/ration3 ,,figure #acj4 ,! be/ arrangem5t ( su* a %utt] is illu/rat$ 9 ,figure #acj at ,a4 ,! %ad$ portion %[s ! op5+2 above is ! iron slide1 pref]ably "o-sixte5? in* metal held up by a /r+4 ,at ! top is a /ep :i* w prev5t ! %utt] f be+ pull$ up out ( ! guides1 = _m op]ators w\ld d ?is if ! /ep 7 n !re4 ,x is be/ to m\nt ! %utt] on a l>ge piece ( heavy metal :i* c !n be bolt$ to ! wall ( ! room4 ,! hole 9 ! wall c !n be cut to ! "r proportions4 ,:5 ! ma*9e is 9 place ! %utt] c be plac$ v accurately4 ,9 ?is way x w be possible to arrange = ! smalle/ possible op5+ ?r\gh :i* ! ma*9e c "w4 ,mak+ up ! %utt]1 z sugge/$ above1 is fur!r ( great advantage 9 old op]at+ rooms ( flimsy wood con/ruction4 ,if ! guides 9 su* places are fa/5$ indep5d5tly to ! wall x is possible t !y w n always rema9 9 l9e ) ea* o!r4 ,a slight giv+ ( ! flimsy wall on "o side may cause !m to b9d ! %utt] & prev5t its free desc5t4 ,if ! metal on :i* ! %utt] guides are m\nt$ is /rong & heavy & ! guides !mselves sub/antially made1 !re w be b little *ance to get !m askew4 ,9 t "p ( ! guides 9 :i* ! %utt] runs !re mu/ be no screws1 rivets1 or any?+ else t c\ld "w loose & ob/ruct ! %utt]s4 ,good me?ods ( mak+ up ! guides are %[n 9 ,figure #acj1 at ,b & ,c4 ,!y %\ld be loose en\gh to "w )\t lubrication4 ,at ! bottom !re %\ld be a bump] to /op ! fall at ! prop] place4 ,?is bump] %\ld be padd$ ) "s firepro( or sl[-burn+ mat]ial & %\ld be n>r[4 ,if x is made wide ! op]ator is apt to use x z a %elf = tools or o!r ?+s & ?is w\ld prev5t x f clos+ prop]ly 9 case ( fire4 ,all ( ! %utt]s mu/ be normally self-clos+ & mu/ be held op5 by "s arrangem5t :i* c readily be work$ by ! op]ator2 or1 9 case he fails to close !m1 !y %\ld be arrang$ s t ! flames w cause !m to close automatically4 ,?is is (t5 arrang$ = by simply atta*+ a light /rong /r+ to ea* %utt]1 runn+ x ?r\gh a hook eye directly above & atta*+ x to a ma/] /r+ :i* is l$ ov] e place at :i* !re is ?\ght to be a likelihood ( fire4 ,! idea is1 t ! fir/ spread ( flames %all /rike ?is /r+ & by burn+ x1 release all ( ! %utt]s4 ,9 ord] to enable ! op]ator to drop ! %utt] p]haps be=e ! flames h spread at all1 ! /r+ is c>ri$ to ! door & fa/5$ s t he1 on leav+ ! room1 may quickly release x4 ,x is ev5 bett] to c>ry x /ill f>!r s t "o c release x f ! outside4 ,"s p h recomm5d$ t ^! /r+s be soak$ 9 oil to make !m m inflammable & t>r$ rope has ev5 be5 made m&atory = simil> purposes 9 ord9ances4 ,?is might make ! /r+ m readily inflammable1 b x w\ld at ! same "t make x la/ long]4 ,a /r+ or rope s treat$ w\ld act l a lamp wick & ! bett] soak$ or t>r$ x might be1 ! long] w\ld x la/ & ?us fail to its purpose4 ,illu/ration3 ,,figure #aca4 ,! pr9ciple ( ! arrangem5t ( /r+s is %[n 9 ,figure #aca4 ,! /r+ is fa/5$ at ! door 9 a mann] all[+ ( easy & quick removal4 ,in/ead ( ! /r+s1 light *a9s may be us$ provid$ t at a suffici5t numb] ( places fusible l9ks are ins]t$4 ,su* l9ks are made up ( an alloy :i* melts at a l[ temp]ature & all[s ! %utt]s to drop j z !y w\ld 9 ! case ( a /r+ burn+ 9 two4 ,9 _m cases ! /r+s are run ov] groov$ pulleys4 ,?is is1 h[ev]1 inadvisable4 ,exp]i5ce has prov$ t v (t5 ! /r+ has come out ( ! groove & is w$g$ 9 betwe5 ! %aft ( ! pulley & ! side s t x w n all[ ! %utt] to desc5d at all4 ,a sub/antial hook eye is mu* bett] ?an any pulley4 ,! /ra9 be+ tak5 (f ! /r+ :5 x sep>ates1 !re is no friction & x slides ?r\gh ! eyes v readily4 ,! door & ! v5t flue may all be br\ght "u control ( ! same /r+ s t all w op]ate toge!r1 ! v5t ( c\rse op5+ :ile ! o!rs close4 ,:]e !re is b "o door !re is little ne$ ( connect+ x ) ! %utt]s1 s9ce1 if x is provid$ ) spr+ h+es x w naturally close aft] ! op]ator has pass$ ?r\gh x4 ,9 "s op]at+ rooms1 h[ev]1 !re are two doors & bo? are (t5 f\nd op54 ,9 case ( fire 9 su* a boo? x is extremely likely t "o ( ! doors w\ld be left op5 unless x is provid$ ) "s automatic mann] ( clos+4 ,at ,d1 ,figure #acj is %[n a %utt]1 provid$ ) /rong spr+ h+es1 :i* closes ov] ! op5+ f ! outside4 ,su* %utt]s %\ld n be us$ :]e !re is room = ! drop %utt]s4 ,:]e x is necess>y to h !m1 !y %\ld always be arrang$ on ! outside ( ! boo?2 if on ! inside !re is too mu* *ance ( ob/acles be+ 9 ! way to prev5t _! clos+4 ,x is v desirable t all ( ! %utt]s be clos$ aft] ea* %[4 ,if ?is is done !re w be /rong assurance t !y w be 9 work+ ord] 9 case ( ne$ & ?is is ab\t ! only way 9 :i* !y c be kept 9 ord]4 ,! /r+ arrangem5t above describ$ is1 h[ev]1 n well suit$ to ?is purpose unless ea* %utt] /r+ be deta*able f ! ma9 /r+4 ,!re are also v>i\s o!r ways ( accompli%+ ?is :i* w readily sugge/ !mselves to ! op]ator4 ,9 e op]at+ room !re %\ld be ample provision = keep+ tools b x is advisable to h all tools1 t are n kept 9 ! lock]s1 on hooks in/ead ( %elves4 ,x is be/ to limit ! am\nt ( %elv+ to :at is actually necess>y4 ,%elv+ (f]s great temptation = ! accumulation ( rubbi%4 ,!re mu/ be a %elf ^u :i* to locate ! rew9d+ app>atus & ^u :i* to place ! ma*9e :ile look+ x ov] or mak+ repairs1 also a %elf to hold a small vise1 etc4 ,b ?is is all2 any additional %elv+ w be inexp$i5t4 ,a lock] = tools c easily be arrang$ "u ! rew9d %elf4 ,a good safe place is an enc\ragem5t to an op]ator to keep a supply ( good tools & no?+ is m ess5tial to ! prop] managem5t ( a ma*9e ?an good tools4 ,if ! op]at+ room is l>ge en\gh1 x may also conta9 a lock] = clo!s b ?is %\ld be firepro(4 ,pref]ably1 h[ev]1 ! clo!s lock] %\ld be outside ( ! room1 s9ce a film fire gives "o b little "t to pick up clo!s or any?+ else4 ,!re %\ld1 fur!r1 be a metal pail or receptacle ( "s k9d = hot c>bons tak5 f ! lamps f "t to "t4 ,a wise op]ator w also provide himself ) a small receptacle 9 :i* he c keep ! pieces ( film :i* he f9ds x is necess>y to cut out ( films receiv$ f ! ex*anges4 ,! inspection ( films 9 ! ex*ange is (t5 v p]functory & _m l5g?s are left 9 t %\ld be cut out4 ,cutt+ !m out & sav+ !m = a "t w (t5 help an op]ator to w9 out 9 disputes ) 8 film ex*ange4 ,!re are op]at+ rooms :i* h film boxes built into ! wall 9 firepro( mann]1 "s ( !m ev5 surr\nd$ by wat]4 ,at ! pres5t "t !re are a numb] ( good portable boxes on ! m>ket s t ?is is unnecess>y4 ,wir+ ( ,op]at+ ,room4--,e op]at+ room mu/ h at lea/ two circuits run into x2 "o = ! arc lamp & ano!r = "o or m inc&esc5t lights4 ,9 ! l>g] cities an em]g5cy light+ sy/em is requir$ = all p>ts ( ! h\se us$ by ! audi5ce4 ,?is sy/em is always entirely indep5d5t ( ! ma9 s]vice & is suppos$ to furni% suffici5t light = ! audi5ce 9 case ! o!r light+ sy/em %\ld fail4 ,x w be well if "o light connect$ to ! em]g5cy sy/em is arrang$ 9 ! op]at+ room4 ,if ?is is done1 !re mu/ be special provisions t no cords1 fan motors1 or portables be connect$ to x4 ,a %ort circuit1 or tr\ble ( any k9d on ?is light might put ! :ole em]g5cy sy/em out ( op]ation4 ,if su* a light is in/all$1 x %\ld be at ! ceil+ & protect$ by a /rong wire gu>d fa/5$ to ! outlet box4 ,all wires c>ri$ into ! op]at+ room %\ld be 9 conduit1 ) ! exception ( ! asbe/os cov]$ wires us$ ) arc lamps & resi/ances4 ,9 addition to ! inc&esc5t light above m5tion$1 !re %\ld be sev]al o!r lights s arrang$ t good light c be obta9$ 9 any "p ( ! room4 ,! color ( walls be+ d>k !re is b little reflection & a s+le light w only illum9ate a small space4 ,"o light %\ld be arrang$ above ! rew9d reel & !re is (t5 ano!r arrang$ "u a piece ( glass 9 a %elf above :i* films are pat*$4 ,only ! be/ re9=c$ cord %\ld be us$ & all "w t is /ation>y %\ld be 9 conduit4 ,sev]al outlets %\ld be arrang$ = portable cords s t "o may h a light to br+ d[n to ! take-up reel or close to ! floor if necess>y4 ,e inc&esc5t lamp 9 ! op]at+ room %\ld be protect$ by a sub/antial wire gu>d fa/5$ to ! socket4 ,fan motors %\ld be provid$ ) /rong brackets locat$ ne> ! ceil+ & close to ! outlet f :i* ! motor is to be run4 ,fan motors %\ld nev] be all[$ ^u ! floor4 ,:]e rew9d+ is to be done by motor1 x w be well to arrange a sep>ate circuit = ?is motor indep5d5t ( all lights4 ,! commutator "p ( ! motor %\ld be enclos$ s t !re may be no possibility ( a sp>k ignit+ ! film4 ,illu/ration3 ,,figure #acb4 ,figure #acb is a sket* illu/rat+ ! arrangem5t ( wir+ by :i* two arc lamps may be connect$ to ma9s ( suffici5t c>ry+ capacity = "o only4 ,f is ! fuse box 9 :i* ! arc lamp fuses are enclos$ & may be l>ge en\gh to accommodate a set ( fuses = ! inc&esc5t-lamp circuit also4 ,9 _m cases ^! are1 h[ev]1 tak5 f ! h\se circuit s9ce ! met] rate = arc lamps is usually diff]5t f t = inc&esc5t lamps4 ,s is ! ma9 arc-lamp swit* by :i* ! :ole in/allation 9 ! room c be cut (f4 ,?is is necess>y especially if s-call$ comp5s>cs1 economy coils1 or trans=m]s are us$1 = ^! always take "s curr5t if left alive ev5 if ! arc lamp be n burn+4 ,at ,c is ! resi/ance or economy coil :i* s]ves = bo? lamps & at ,s is ! ?r[-ov] swit*4 ,?is swit* is provid$ to make x impossible to burn ! two arcs at ! same "t z ?is w\ld ov]load ! small capacity ma9s4 ,! above is a *eap arrangem5t & is in/all$ only :]e a set ( ma9s exi/s :i* is too small to supply m ?an "o arc at a "t4 ,x is n to be advis$ = a new in/allation because x is ( great advantage to be able to burn bo? arcs at ! same "t4 ,:5 *ang+ rapidly f "o ma*9e to ! o!r x is ( advantage to h ! second "o on = a %ort "t be=e ! fir/ is (f1 n only to save a little "t1 b also = br++ electrode po9ts to ! prop] %ape4 ,:]ev] x is possible to d s always provide ma9s ( suffici5t size to fe$ all ( ! arcs & give ea* lamp its own fuse1 swit*1 & resi/ance or trans=m]4 ,illu/ration3 ,,figure #acc4 ,figure #acc %[s a me?od by :i* x is possible to arrange = ei!r "o ( two arcs to be run f a rectifi] ,r1 indicat$ by ! squ>e at ! left1 or trans=m] ,t1 at ! "r4 ,9 case rectifi]s1 heavy trans=m]s t _c well be rais$ to ! ceil+1 or motor g5]ators are to be in/all$1 !y %\ld be locat$ 9 a sep>ate enclosure :i* mu/ be firepro(4 ,9 g5]al1 all ( ! wir+ 9 ! op]at+ rooms mu/ be in/all$ 9 accordance ) ! rules giv5 9 ! *apt] on ,!at] & ,/age ,wir+4 ,^! are ! rules ( ,! ,national ,bo>d ( ,fire ,und]writ]s & are famili>ly kn[n z ! 8,national ,electrical ,code10 or 8,n4,e4,c40 ,,*apt] ,,xvi4 ,,curr5t ,,control ,,= ,,arc ,,lamps4 ,voltages ,requir$4--,! comm]cial di/ribution ( electrical en]gy is at voltages ( #aaj or #bbj1 9 mo/ cases1 & occasionally runs z high z #eej4 ,! direct-curr5t arc requires = its be/ op]ation a voltage ( f #de to #ej1 :ile ! alt]nat+-curr5t arc uses f #cj to #dj4 ,9 ord] to secure satisfactory op]ation ( arc lamps1 x becomes necess>y to provide "s means ( r$uc+ ! voltage at ! arc to ! prop] am\nt4 ,resi/ance ,control4--,! simple/ me?od & ! "o univ]sally applicable is t ( ins]t+ resi/ance 9 s]ies ) ! arc4 ,! drop 9 voltage is equal to ! curr5t multipli$ by ! resi/ance2 h5ce1 if we wi% to decrease our voltage1 say #fe volts1 z w\ld be ! case 9 connection ) a #aaj-volt circuit & a #de-volt arc1 us+ #be amp]es1 we %\ld ne$ a resi/ance ( #b4f ohms4 ,tw5ty-five times #b4f equals #fe volts lo/1 :i* leaves #de volts to op]ate ! arc )4 ,9 connection ) arc lamps1 h[ev]1 x is n only necess>y to l[] ! voltage b "s provision mu/ be made s t ! curr5t1 :5 ! electrodes are br\ght toge!r1 w n become excessive4 ,at ! "t ! arc is /ruck1 i4e41 at ! "t ! electrodes are br\ght 9 contact ) ea* o!r1 ! curr5t is limit$ only by ! extra resi/ance 9 ! circuit1 = ! electrodes !n =m a %ort circuit4 ,9 ! above case1 #aaj volts & a rheo/at ) #b4f ohms resi/ance we %\ld obta91 dur+ ! "t ! electrodes are toge!r1 a curr5t equal to #aaj divid$ by #b4f :i* equals ab\t #dc amp]es4 ,if x 7 n = ?is resi/ance ! curr5t w\ld rise to sev]al times ?is value & bl[ out any fuse we might provide4 ,x is n necess>y t ?is resi/ance be 9 any p>ticul> place2 if we h a v long run ( small wire f ! s]vice to ! arc1 !re may be suffici5t resi/ance 9 ?is s t v little extra resi/ance is requir$4 ,some:]e1 h[ev]1 !re mu/ be "s provision ins]t$ 9 ! circuit to prev5t ! curr5t f becom+ too great at ! "t ! electrodes are br\ght toge!r4 ,9 pass+ x may be not$ at ?is po9t t an arc c be />t$ )\t any resi/ance 9 ! circuit by bridg+ ! space betwe5 ! electrodes ) a small fuse wire :i* w melt ! in/ant ! curr5t is turn$ on & e/abli% ! arc4 ,! resi/ance me?od is v wa/eful ( en]gy1 z ! foll[+ tabulation w %[2 b ) direct curr5ts x is ! only me?od available1 unless we are will+ to provide a motor g5]ator to give u ! prop] voltage4 ,= alt]nat+ curr5ts1 resi/ances are n mu* us$1 except ) travel+ %[s :]e ! portability ( ! control z well z its fitness = all possible conditions is an important consid]ation4 ,,table ,,iv4 ,,%[+ ,,wa/e ,,( ,,en]gy ,,) ,,use ,,( ,,resi/ances ,,= ,,v>i\s ,,voltages4 ---------------------------------------- -- ,volts ,curr5t ,watts ,lo/ ,useful ,watts ---------------------------------------- -- #aaj #cj #aiej #acej #bbj #cj #ebej #acej #eej #cj #aeaej #acej ---------------------------------------- -- ,! tabulation 9 ,table ,,iv %[s t ! high] our voltage ! great] ! loss ( en]gy caus$ by ! use ( resi/ances4 ,! figures apply1 z giv51 only to cases :]e only a s+le arc lamp is us$4 ,:]e sev]al c be us$ 9 s]ies ! loss due to high voltage ne$ n be great] ?an ) l[] voltage4 ,illu/ration3 ,,figure #acd4 ,9 ,figure #acd we h %[n diagrammatically ! usual repres5tation ( a resi/ance4 ,! m wire !re is 9 circuit1 ! high] w be ! resi/ance & ! great] ! drop caus$ by a giv5 curr5t4 ,if we l5g!n ! arc1 ! curr5t w be some:at decreas$ & ! drop 9 voltage ov] ! resi/ance w be less1 ?us all[+ a rise 9 ! voltage at ! t]m9als ( ! lamp4 ,! en]gy lo/ 9 resi/ances takes ! =m ( heat & all resi/ances1 us$ = ! control ( arc lamps1 give (f mu* heat & mu/ be locat$ 9 safe places4 ,! heat+ also makes !m objectionable 9 small op]at+ rooms 9 summ]1 b some:at welcome 9 w9t]4 ,! heat g5]at$ 9 a wire is proportional to ! squ>e ( ! curr5t2 h5ce if we d\ble ! curr5t ?r\gh a c]ta9 resi/ance we %all h f\r times ! heat4 ,if sev]al resi/ances are connect$ 9 s]ies ! total resi/ance w be equal to ! sum ( ! individual resi/ances1 & ! curr5t w be correspond+ly decreas$4 ,if we wi% to get m curr5t ?an c be obta9$ ) ! use ( "o resi/ance we may connect up two or m 9 p>allel4 ,two equal resi/ances connect$ 9 p>allel w give approximately d\ble ! curr5t t c be obta9$ ?r\gh "o ( !m4 ,illu/ration3 ,,figure #ace4 ,reactance ,control4--,a reactance1 %[n diagrammatically 9 ,figure #ace1 may take ! place ( ! resi/ance 9 alt]nat+-curr5t circuits & is pref]able because x wa/es comp>atively little en]gy4 ,x l[]s ! voltage ov] ! arc b its op]ation dep5ds ^u a c\nt] e4m4f4 :i* opposes ! impress$ e4m4f4 ( ! circuit & mu/ be subtract$ f ! latt]4 ,! nature ( reactances z well z ( trans=mation1 etc41 has be5 fully treat$ 9 ano!r "w ( ! au?ors'1 entitl$1 8,alt]nat+ ,curr5t ,!ory1 ,practice & ,diagrams0 & w\ld c>ry u too f> 7 x to be discuss$ 9 ?is "w4 ,e reactive coil is made up ( copp] wire w\nd ^u an iron core & conta9s bo? resi/ance & reactance4 ,s f> z ! resi/ance 9 x is conc]n$1 ?is causes a wa/e ( en]gy1 b x is always v small4 ,!re is also a wa/e ( en]gy due to ! hy/]esis & eddy-curr5t losses 9 ! iron1 b ?is is also small4 ,! reactance is proportional to ! squ>e ( ! numb] ( turns ( wire1 if ! iron core is fix$1 & may be controll$ ei!r by adju/+ ! position ( an iron core 9 a helix1 or by adju/+ ! numb] ( turns ( wire ar\nd a fix$ iron core4 ,! light obta9able ?r\gh a reactance is n ( ! be/ quality & reactances are n mu* us$4 ,trans=mation ,control4--,ano!r me?od ( l[]+ ! voltage is by means ( ! trans=m]4 ,a diagram ( an ord9>y trans=m] w9d+ is giv5 9 ,figure #acf4 ,! f9e-wire w9d+ is ! prim>y w9d+ or coil1 if ! trans=m] is us$ to l[] ! voltage2 & ! o!r is kn[n z ! second>y w9d+ or coil4 ,! en]gy 9 bo? coils ( ! trans=m]1 neglect+ ! iron & copp] losses1 is always exactly equal4 ,! ratio ( voltage betwe5 ! prim>y & second>y t]m9als is 9 direct proportion to ! numb] ( turns ( wire 9 ea*4 ,if !re are half z _m turns 9 ! second>y w9d+ z 9 ! prim>y1 ! voltage w be j "o-half1 b ! curr5t w be d\ble4 ,! trans=m] is self-regulat+1 )9 ! limits ( its capacity1 & :atev] en]gy is tak5 f ! second>y1 ! prim>y w automatically supply4 ,illu/ration3 ,,figure #acf4 ,a trans=m] mu/ be specially built = ! voltage & frequ5cy1 at :i* x is to be us$2 b _m ( !m are provid$ ) taps1 su* z %[n 9 ,figure #acf1 by :i* small adju/m5ts ( voltage or curr5t c be made4 ,a trans=m] mu/ always be connect$ s t ! swit*1 :5 op51 w disconnect ! prim>y wires4 ,if ^! rema9 clos$ !re w be a small curr5t ?r\gh ! prim>y w9d+ :i* w mean a consid]able wa/e ( en]gy4 ,auto-trans=m] ,control4--,! auto-trans=m] is a special type ( trans=m] us$ to obta9 r$uc$ voltage & increas$ curr5t4 ,its pr9ciple may be ga!r$ f ,figure #acg4 ,!re is an iron core & two coils ( wire z 9 ord9>y trans=m]s b ! two coils are connect$ 9 s]ies1 z %[n 9 ! figure4 ,x w also be not$ t ! arc is connect$ directly across "o ( ! coils4 ,! l[] portion ( ! w9d+ or coil is trav]s$ by ! alt]nat+ curr5t f ! ma9s at all times & ?is curr5t also passes ?r\gh ! arc lamp :5 ! circuit ?r\gh x is clos$4 ,! curr5t pass+ ?r\gh ! l[] coil & ! arc induces a curr5t 9 ! upp] portion ( ! w9d+ & ^! two curr5ts !n pass 9 p>allel ?r\gh ! lamp4 ,illu/ration3 ,,figure #acg4 ,illu/ration3 ,,figure #ach4 ,:5 ! arc circuit is op51 bo? coils are 9 s]ies & act z *oke coils s t b v little curr5t is us$4 ,! auto-trans=m] may be design$ to r$uce ! voltage to any desirable am\nt & ! curr5t w be correspond+ly increas$1 neglect+ all losses4 ,illu/ration3 ,,figure #aci4 ,if ! r$uc$ voltage 7 to be obta9$ f an ord9>y trans=m]1 ! second>y coil w\ld be call$ ^u to c>ry ! full curr5t us$ by ! lamp1 :ile ) ?is connection x c>ries mu* less4 ,if ! two coils are equal1 ! voltage w be r$uc$ "o-half1 ! curr5t w be d\bl$1 & only half ( ! curr5t w pass ?r\gh ! second>y coil4 ,! ne>] equal ! prim>y & second>y voltages are1 ! great] ! sav+ 9 copp] 9 ! second>y coil4 ,if x 7 int5d$ to trans=m f #aaj to #ajj volts1 ! capacity ( ! second>y w9d+ w\ld ne$ to be only "o-elev5? ( ! total capacity4 ,! auto-trans=m] is a v useful device b on acc\nt ( ! fact t ! high voltage exi/s 9 all ( its p>ts1 x is n safe to use ) ! high comm]cial voltages outside4 ,illu/ration3 ,,figure #adj4 ,if ! auto-trans=m] is connect$ z %[n 9 ,figure #ach1 x c be us$ to raise ! voltage2 b 9 ?is case ! curr5t w be decreas$4 ,^! auto-trans=m]s1 z well z ! ord9>y trans=m]1 mu/ always be connect$ to ! s\rce ( en]gy by means ( a swit* s t !y may be disconnect$ :5 n 9 use2 o!rwise !re w be a small curr5t 9 ! prim>y circuit all ! "t :i* w %[ up q /rong on ! watt h\r met]4 ,trans=m]s & auto-trans=m]s are arrang$ to be portable4 ,a g5]al view is giv5 9 ,figures #aci & #adj2 ! =m] be+ ! ,edison & ! latt] ! ,=t ,wayne4 ,motor-,g5]ator ,control4--,! prop] voltage = ! op]ation ( arc lamps c be obta9$ by ! use ( motor-g5]ators4 ,a motor-g5]ator is a g5]ator driv5 by a motor1 ! two armatures be+ plac$ ^u "o %aft or belt$ toge!r4 ,! motor may be driv5 by a curr5t ( any voltage desir$4 ,! diagram ( su* an outfit = direct curr5t is %[n 9 ,figure #ada4 ,?is type ( ma*9e is us$1 z a rule1 only :]e ! supply voltage is mu* high] ?an t us$ at ! arc4 ,resi/ance mu/ be us$ at ea* arc lamp4 ,illu/ration3 ,,figure #ada4 ,figure #adb %[s ! connections ( an alt]nat+-curr5t to a direct-curr5t motor-g5]ator ( ! ,=t ,wayne ,electric ,company4 ,! swit* ,a is us$ to />t x & is %[n connect$ to a ?ree-phase l9e4 ,aside f ! field w9d+ !re are ?ree wires lead+ to ! g5]ator4 ,! wire ,b c>ries a comp\nd w9d+ inside ( ! g5]ator :i* opposes ! magnetization ( ! %unt w9d+4 ,! wire ,c c>ries ano!r comp\nd w9d+ :i* is arrang$ to /r5g!n ! %unt field4 ,d is a box conta9+ two resi/ances1 "o = ea* arc lamp %[n4 ,if only "o lamp is to burn1 ! swit* ,e is clos$ & ! arc />t$ 9 ! usual way4 ,:5 ready to *ange to ! o!r arc lamp1 swit* ,e mu/ be op5$1 ! swit* on ! second arc lamp clos$1 & ! arc /ruck4 ,!n ext+ui% ! fir/ arc & close ! swit* ,e aga94 ,if bo? lamps are to be us$ cont9ually1 swit* ,e mu/ be left op54 ,illu/ration3 ,,figure #adb4 ,z long z curr5t is us$ ?r\gh wire ,b1 !re is no loss ( en]gy 9 any resi/ance & %\ld ! curr5t 9 ! arc rise1 z :5 ! electrodes are br\ght toge!r1 ! increas$ curr5t 9 ! s]ies w9d+1 cut into ?is wire1 w\ld weak5 ! field & ?us keep ! curr5t d[n4 ,:5 curr5t is us$ ?r\gh ! wire ,c1 ! s]ies field w9d+ /r5g!ns ! field & builds up ! voltage suffici5tly s t ! lamps may be op]at$ ?r\gh ! resi/ances4 ,! field /r5g? may be fur!r regulat$ by ! rheo/at ,r4 ,ano!r connection ( ! ,=t ,wayne motor-g5]ator is %[n 9 ,figure #adc4 ,9 ?is case ! lamps may be op]at$ ei!r f ! comp5s>c ,c or ! g5]ator4 ,by ?r[+ ei!r "o ( ! swit*es connect$ to ! arc lamps up1 ! correspond+ arc lamp is connect$ to ! comp5s>c4 ,by ?r[+ ! swit* d[n x is f$ f ! g5]ator4 ,! lamp1 by :i* ! picture is be+ project$1 %\ld be f$ f ! g5]ator & :5 ne>ly ready to *ange1 ! o!r may be />t$ on ! comp5s>c4 ,?is lamp w burn ) a %ort arc & :5 x is connect$ 9 p>allel ) ! "o on ! g5]ator1 x w imm$iately ext+ui% ! latt]4 ,no attempt mu/ be made to burn bo? arcs f ei!r ! comp5s>c or ! g5]ator4 ,?is g5]ator is also w\nd to protect itself aga9/ an ov]load4 ,illu/ration3 ,,figure #adc4 ,:]e ^! connections are to be in/all$1 x w be be/ to consult ! local inspection dep>tm5ts conc]n+ ! necess>y fus+ = ! comp5s>c & ! g5]ator4 ,9 "s localities ! possibility ( ?r[+ bo? arcs on ei!r comp5s>c or g5]ator1 :]e ^! h capacity = b "o arc at a "t1 w be consid]$ v objectionable4 ,illu/ration3 ,,figure #add4 ,ano!r comb9ation ( motor & g5]ator sometimes us$ is %[n 9 ,figure #add4 ,by trac+ out ! circuits x w be se5 t ! armatures ( bo? are 9 s]ies & t ! electrodes1 :5 !y come toge!r1 =m a %unt ab\t ,b4 ,) ! electrodes sep>at$1 if curr5t is turn$ on1 x mu/ pass ?r\gh bo? armatures 9 s]ies4 ,?us ! c\nt] e4m4f4 ( bo? armatures opposes t ( ! l9e & !y op]ate at a c]ta9 spe$4 ,ea* motor has a natural t5d5cy to s5d curr5t 9 opposition to t impress$ ^u x by ! l9e4 ,if !n ! electrodes are br\ght toge!r1 !y at once =m a %ort circuit ar\nd ! armature ( ,b4 ,! curr5t 9 ,b rev]ses & x !n beg9s to act z a g5]ator & s5ds curr5t ?r\gh ! arc lamp4 ,! curr5t :i* passes ?r\gh ! armature ( ,a also passes ?r\gh ! arc lamp4 ,a is !n a motor & op]ates ,b z a g5]ator4 ,! voltage at ! arc is less ?an ! l9e voltage by z mu* z ! c\nt] e4m4f4 ( motor ,a am\nts to1 neglect+ ! drop 9 voltage due to resi/ance4 ,no resi/ance is ne$$ if ! w9d+ is prop]ly arrang$ & !re is n ! less 9 heat :i* goes ) ! use ( resi/ances4 ,?is arrangem5t c be us$ ) direct-curr5t circuits only4 ,x is n suitable :]e ! supply voltage is v mu* high] ?an ! voltage us$ at ! arc4 ,a field rheo/at is provid$ to adju/ ! field /r5g? ( ,b4 ,a is equipp$ ) ! ord9>y motor-/>t+ rheo/at only4 ,rot>y ,conv]t] ,control4--,?is is a ma*9e us$ only :]e ! supply is alt]nat+ curr5t4 ,! voltage deliv]$ to ! conv]t] mu/ be ! same z t desir$ at ! direct-curr5t t]m9als4 ,?is ma*9e has an armature ess5tially simil> to t ( a direct-curr5t dynamo4 ,alt]nat+ curr5t is suppli$ to x at "o set ( t]m9als & direct curr5t is tak5 f ! o!rs4 ,?is armature acts z motor & g5]ator at ! same "t4 ,:atev] voltage regulat+ is necess>y ) ?is ma*9e mu/ be done on ! alt]nat+-curr5t side4 ,*ang+ ! field /r5g? does n mat]ially affect ! voltage s t no means = regulat+ ! field /r5g? is provid$4 ,! pol>ity ( ! direct-curr5t t]m9als dep5ds ^u ! position ! armature happ5s to be 9 :5 ! alt]nat+ curr5t is appli$ to x & is v apt to come 9 wrong :5 ! ma*9e is />t$4 ,x is !re=e necess>y to h a pol>ity indicat+ voltmet] 9 ! circuit & to wat* x :5 />t+ ! ma*9e4 ,if ! pol>ity is wrong1 ! swit* mu/ be op5$ & 9 a mom5t ?r[n 9 aga92 & if /ill wrong1 ?is process mu/ be repeat$ until ! pol>ity comes "r4 ,ea* arc lamp f$ f a conv]t] mu/ be equipp$ ) resi/ance4 ,illu/ration3 ,,figure #ade4 ,! ,m>t9 rot>y conv]t] is especially design$ = motion-picture "w & may be provid$ ) ! prop] connections = ei!r s+le-phase1 two-phase1 or ?ree-phase "w4 ,!re is a /ator r+ :i* entirely surr\nds ! armature4 ,?is r+ is made up ( lam9at$ disks ) squirrel-cage b>s & slots alt]nat+4 ,! squirrel-cage b>s are jo9$ at ! end to a copp] b> & x is by ! aid ( ?is squirrel-cage t ! motor may be />t$ & br\ght into /ep4 ,! squirrel-cage also prev5ts 8hunt+0 :i* is "o ( ! common tr\bles exp]i5c$ ) syn*ron\s motors or conv]t]s4 ,into ! slots are w\nd special comp5sat+ coils to balance ! armature reaction & keep ! neutral po9t 9 con/ant position f no load to full load4 ,?is prev5ts sp>k+ at ! bru%es4 ,on ! outside ( ?is damp] r+ or squirrel-cage w9d+ is ! regul> %unt-field w9d+ us$ ) direct-curr5t motors or g5]ators4 ,figure #ade is a diagram %[+ ! connections ( ! ,m>t9 ,rot>y ,conv]t] z in/all$ by ! ,nor?we/]n ,electric ,company ( ,*icago4 ,?is swit*bo>d is equipp$ to op]ate two mov+-picture arcs1 two dissolv+ /]eopticon lamps1 & "o spot light4 ,ea* lamp is provid$ ) a ?r[-ov] swit* s t curr5t may be us$1 ei!r f ! alt]nat+-curr5t ma9s direct or f ! direct-curr5t side ( ! conv]t]4 ,figure #adf is ano!r panel bo>d = mov+-picture "w made up by ! same company4 ,9 ?is case resi/ances are provid$ = use :5 ! arc lamps are op]at$ f ! conv]t]4 ,9 case x is desir$ to run f ! alt]nat+-curr5t ma9s1 trans=m]s or comp5s>cs are us$4 ,! em]g5cy feature ( ^! panel bo>ds is highly to be recomm5d$4 ,x mu/ be borne 9 m9d t "o may sudd5ly be =c$ to deal ) an op]ator :o has nev] se5 a conv]t] & kn[s no?+ ( its op]ation2 & !re is also always ! possibility ( "s tr\ble ) ! ma*9e4 ,illu/ration3 ,,figure #adf4 ,a ,m>t9 rot>y conv]t] to be op]at$ f a s+le-phase l9e is %[n 9 ,figure #adg4 ,?is ma*9e is />t$ ?r\gh ! commutator side4 ,9 ord] to />t ?is ma*9e x is necess>y fir/ to close ! ma9 swit*4 ,next ?r[ ! swit* #b to ! "r & leave x !re = ab\t five seconds4 ,x may !n be ?r[n ov] to ! runn+ position at ! left & all[$ to rema9 9 ?is position4 ,if ! pol>ity is n correct1 ! swit* mu/ be op5$ aga9 = an in/ant & clos$ aga92 & ?is process mu/ be repeat$ until ! pol>ity comes 9 "r4 ,to /op ! conv]t]1 fir/ op5 ! ma9 swit* & !n ! ?r[-ov] swit*4 ,! mann] 9 :i* ! above ma*9es are pref]ably set up is %[n 9 ,figure #adh4 ,illu/ration3 ,,figure #adg4 ,illu/ration3 ,,figure #adh4 ,! ,m]cury-,arc ,rectifi] ,control4--,! m]cury-arc rectifi] has ?ree ess5tial p>ts3 ! rectifi] tube1 ! ma9 reactance1 & ! panel4 ,! rectifi] tube1 ,figure #adi1 is a glass vessel f :i* ! air has be5 exhau/$ & 9 :i* !re are two graphite electrodes1 ,a & ,a1 & "o m]cury electrode ,b4 ,f ! two upp] electrodes curr5t c pass 9 ! direction ( ! m]cury only4 ,!y are always positive & ! t]m anode is usually appli$ to !m4 ,b is always negative & ! t]m ca?ode applies to x4 ,ea* anode is connect$ to a sep>ate side ( an alt]nat+-curr5t circuit & is ?us subject alt]nately to positive or negative pot5tial4 ,:5 curr5t has once be5 />t$1 ! tube is fill$ ) ioniz$ m]cury vapor ?r\gh :i* ! electricity c fl[1 f :i*ev] ( ! two anodes is positive1 t[>d ! ca?ode ,b4 ,"u no conditions1 h[ev]1 c electricity fl[ f ! m]cury 9 ! tube t[>d ! anodes4 ,! action ( ! tube is />t$ by tilt+ x suffici5tly1 s t ! m]cury 9 ! bottom ( x connects ! />t+ anode ,c to ,a4 ,?is />ts ! curr5t & :5 ! tube is return$ to its upright position1 ! m]cury bridge f ,c to ,a is int]rupt$2 b ! curr5t !n cont9ues f "o or ! o!r ( ! anodes4 ,%\ld ! curr5t be int]rupt$1 ev5 = an in/ant1 ! tube w\ld cease to "w until x _h be5 tilt$ aga94 ,9 ord] to provide t ! curr5t1 :i* is alt]nat+ & comes to z]o twice 9 e cycle1 may nev] cease 9 ! tube1 x is necess>y to provide "s reactance4 ,su* a reactance causes ! curr5t to lag beh9d ! e4m4f4 & 9 consequ5ce lap ov] ! "t :5 x w\ld o!rwise fall to z]o4 ,:ile ! curr5t f ! rectifi] is always 9 ! same direction1 positive f ,b to ! lamp1 x is also a pulsat+ curr5t *ang+ 9 value to "s ext5t4 ,9 ,figure #adi a complete diagram ( ! connections ( ! ,g5]al ,electric ,company ,m]cury ,arc ,rectifi] = mov+-picture arcs is giv54 ,?is type ( rectifi] is entirely automatic & is mu* us$4 ,! front & back connections are %[n 9 ,figure #aej4 ,! foll[+ in/ructions are tak5 f a publication ( ! ,g5]al ,electric ,company3 ,! leads m>k$ ,a ,c %\ld be connect$ to ! l[] side ( a d\ble-pole swit* locat$ ne> ! mov+-picture ma*9e4 ,! upp] /uds ( ! swit* %\ld be connect$ to ! ,a ,c s\rce ( supply4 ,illu/ration3 ,,figure #adi4 ,! leads m>k$ & - %\ld be connect$1 respectively1 to ! positive 7upp]7 & negative 7l[]7 electrodes ( ! mov+-picture lamp4 ,if ! ,a ,c supply voltage is #aaj volts2 !n connect ! flexible lead m>k$ ,z to /ud m>k$ #ab2 & flexible lead m>k$ ,y to /ud m>k$ #f4 ,if ! ,a ,c supply voltage is #bbj volts2 !n connect lead ,z to /ud #g1 & lead ,y to /ud #a4 ,,note3--,d n di/urb ! o!r connections t are made on /uds #a1 #f1 #g1 & #ab1 b only place leads ,y & ,z z direct$4 ,illu/ration3 ,,figure #aej4 ,! tube hold] %\ld be rev]s$ s t ! clip & support w be turn$ away f ! panel in/ead ( t[>ds ! panel1 z x is :5 %ipp$4 ,remove ! tube f its box1 be+ v c>eful n to h&le x r\ghly & n to /ra9 ! seals 9 any way :atev]4 ,c>e mu/ also be tak5 to prev5t ! m]cury f sudd5ly fl[+ into any ( ! arms2 o!rwise ! resultant p\nd+ might damage !m4 ,exam9e ! tube = vacuum by not+ ! s\nd ! m]cury makes :5 all[$ to roll g5tly ab\t 9 ! l>ge *amb]4 ,if x makes a cle>1 metallic click1 ! vacuum is good2 b1 if ! s\nd is dull & ! m]cury sluggi% 9 mov+1 ! vacuum is ei!r p>tially or :olly de/roy$4 ,if ! vacuum is poor1 ! life ( ! tube may be %ort or x may n />t at all4 ,to insure c>eful h&l+ & safe deliv]y1 ,m]cury-,arc ,rectifi] tubes are always %ipp$ by express 9 ! special box z !y come f ! factory4 ,place ! tube 9 ! hold] by ins]t+ ! small "p ( ! tube j above ! anode arms 9 ! upp] clip2 !n g5tly l[] x until x re/s firmly on ! l[] support4 ,connect ! tube & bead$ leads accord+ to ! above diagram4 ,adju/m5t ( curr5t 7numb] ( amp]es7 at ! arc is obta9$ by connect+ leads m>k$ ,x to /uds m>k$ #aa1 #i1 #g1 #e1 #c1 or #a ( ! regulat+ reactance4 ,/ud #a gives ! maximum & /ud #aa ! m9imum numb] ( amp]es4 ,9 />t+ up ! fir/ "t x is be/ to />t ) lead ,x on /ud #aa & move t[>d ! maximum position by /eps until ! desir$ curr5t is obta9$1 z indicat$ by ! ammet]4 ,= ?is adju/m5t x is advisable to connect an ammet] 9 s]ies ) ! arc 9 ! mov+-picture ma*9e4 ,) ! above in/ructions c>ri$ out1 all t is necess>y to />t is to close ! swit* 9 ! ,a ,c l9e2 !n br+ ! electrodes ( ! arc toge!r4 ,! automatic %ak+ device %\ld !n rock ! tube until ! arc 9 ! tube />ts2 z soon z ! arc 9 ! tube />ts sep>ate ! electrodes4 ,! be/ & :ite/ light c be obta9$ :5 a #e_/h-;in* cor$-c>bon electrode is us$ above & a #a_/b-;in* solid-c>bon electrode bel[1 c>e be+ tak5 n to get solid c>bons too h>d4 ,! av]age curr5t 9 ! arc %\ld n exce$ #cj amp]es & x w be f\nd t excell5t pictures c be obta9$ ) #be amp]es or ev5 less & ! co/ ( en]gy1 c>bons1 & cond5s]s w be less4 ,,*apt] ,,xvii4 ,,managem5t ,,( ,,g5]ators ,,& ,,motors4 ,op]ation ( ,g5]ators4--,! g5]ator %\ld be locat$ 9 a clean dry place4 ,if x is belt driv51 ! belt %\ld be run horizontal if possible & s t ! slack side w be on top4 ,?is increases ! arc ( contact ) ! pulleys & all[s ! belt to run ) less tight5+4 ,! frame %\ld be provid$ ) a slide = ! purpose ( adju/+ & tight5+4 ,! proportion betwe5 ! l>ge/ & ! smalle/ pulleys us$ close toge!r %\ld n be great] ?an ab\t #f to #a4 ,to />t a dynamo x is be/ fir/ to disconnect x f ! swit*bo>d4 ,/>t x runn+ & adju/ ! voltage by ! field rheo/at4 ,:5 ! voltage has aris5 to its prop] value & ev]y?+ is runn+ smoo?ly1 ! ma9 swit* may be clos$4 ,if !re is mu* ( a load1 x w probably be f\nd t ! voltage has fall5 (f a little & x w be necess>y to re-adju/ x4 ,next1 look c>efully aft] ! bru%es & set !m at ! po9ts :]e !re w be ! lea/ sp>k+4 ,a good mod]n g5]ator %\ld n sp>k at all4 ,all ( ! be>+s mu/ be c>efully look$ aft] & wat*$ = heat+4 ,if !y are n prop]ly oil$ or 9 good condition1 !y may heat consid]ably4 ,! armature %\ld run ) consid]able end play z ?is helps to di/ribute ! oil ov] ! be>+s & ev5 up ! we> on ! commutator surface4 ,small g5]ators sometimes lose _! residual magnetism & x is !n impossible to />t !m g5]at+4 ,9 su* a case ! fields may be connect$ to a live-light+ circuit2 or a small excit+ curr5t may be obta9$ f a batt]y4 ,"o %\ld "k :i* is ! positive pole ( ! field & apply ! batt]y or l9e curr5t accord+ly4 ,a te/ = pol>ity may be made by plac+ ! ends ( wires ( opposite pol>ity 9 a vessel ) wat] & br++ !m )9 an in* or s ( ea* o!r4 ,"u ^! conditions bubbles w be giv5 (f at ! negative pole4 ,! pol>ity ( ! g5]ator w v>y ) ! pol>ity ( ! field1 ! direction ( rotation1 & ! connection ( ! bru%es4 ,by rev]s+ any "o ( ^! we may rev]se ! pol>ity ( ! curr5t deliv]$4 ,%unt dynamos _c well be op]at$ 9 p>allel2 :]e x is desir$ to op]ate sev]al dynamos toge!r1 comp\nd-w\nd ma*9es are us$4 ,op]ation ( ,motors4--,! spe$ ( a direct-curr5t motor is always su* t ! c\nt] e4m4f4 ( ! motor becomes ne>ly equal to ! impress$ e4m4f4 ( ! l9e4 ,9 ord] to spe$ up a motor x is necess>y to weak5 ! fields2 & conv]sely1 to sl[ x d[n we mu/ /r5g!n ! fields4 ,! above me?ods are necess>y if ! motor is to run at a ne>ly fix$ spe$ ) a v>iable load4 ,! spe$ c also be controll$ by a v>iable resi/ance plac$ 9 ! armature circuit4 ,?is me?od1 h[ev]1 does n result 9 a /eady spe$ ) a v>iable load4 ,x has v little effect if ! load is light1 & v mu* if x is heavy4 ,9 ord] to />t a motor x is necess>y to h "s resi/ance 9 ! armature circuit4 ,9 v small motors ! armatures are usually w\nd ) suffici5t resi/ance s t no ext]nal resi/ance is requir$4 ,! l>g] motors are1 h[ev]1 equipp$ ) />t+ boxes :i* limit ! curr5t ?r\gh ! armature until x has atta9$ suffici5t spe$ s t its c\nt] e4m4f4 w keep ! curr5t 9 *eck4 ,^! />t+ boxes are usually w\nd ) f9e wire & _c /& ! />t+ curr5t v long4 ,! h&le mu/ be mov$ ov] /eadily & sl[ly & n all[$ to rema9 on an int]m$iate position unless x is kn[n t ! box is meant to be us$ z a spe$ controll] z well z a />t+ box4 ,! direction ( rotation ( a direct-curr5t motor c be rev]s$ by rev]s+ ei!r ! field or ! armature curr5t4 ,if bo? are rev]s$1 x w cont9ue to run 9 ! same direction4 ,alt]nat+-,curr5t ,motors4--,syn*ron\s alt]nat+-curr5t motors are n us$ 9 !at] "w b ! rot>y conv]t] is frequ5tly us$ & may be consid]$ z su*4 ,?is ma*9e mu/ run at a c]ta9 spe$ :i* dep5ds ^u ! frequ5cy ( ! curr5t suppli$ & ! numb] ( poles on ! ma*9e4 ,rot>y conv]t]s are ( diff]5t types & may be />t$ ei!r f ! direct-curr5t side or f ! alt]nat+-curr5t side4 ,"s ( !m are provid$ ) connections s t ! alt]nat+ curr5t may be appli$ on ! direct-curr5t side ( ! armature4 ,= />t+ & op]at+ ^! conv]t]s1 ! in/ruction ( ! mak] %\ld be consult$4 ,= motor-g5]ators :]e alt]nat+ curr5t is us$1 ! induction motor is g5]ally employ$4 ,x may be ei!r s+le-phase1 two-phase1 or ?ree-phase4 ,all ( ^! are ess5tially con/ant-spe$ motors4 ,simple repulsion motors & s+le-phase induction motors t />t z repulsion motors are rev]s$ by %ift+ ! bru%es4 ,alt]nat+-curr5t s]ies motors are rev]s$ 9 ! same mann] z direct-curr5t motors by rev]s+ ei!r field or armature4 ,if bo? are rev]s$1 ! motor w cont9ue to run 9 ! same direction4 ,a ?ree-phase induction motor w rev]se its direction ( rotation if any two ( ! l9e wires connect$ to ! prim>y w9d+ be rev]s$4 ,if all ?ree wires are *ang$ 9 ord]1 ! direction ( rotation w rema9 un*ang$4 ,syn*ron\s motors :5 />t$ z induction motors are also gov]n$ 9 ?is way4 ,^! motors ( ! l>g] size are g5]ally />t$ ?r\gh an auto-trans=m]4 ,= ! small] ones1 x is cu/om>y to provide a ?r[-ov] swit*1 "o side only ( ! swit* be+ fus$4 ,! motor at />t+ takes v /rong curr5ts :i* w\ld bl[ ! runn+ fuse4 ,to rev]se a two-phase induction motor ! two wires ( "o phase mu/ be rev]s$4 ,,g5]al ,,h9ts4 ,be sure t all belts are suffici5tly tight4 ,see t all be>+s are well oil$4 ,let all %afts h suffici5t end play4 ,use no oil cans ( iron ar\nd dynamos or motors4 ,keep files & o!r iron or /eel away4 ,see t all connections are good & tight4 ,all[ no metal du/ or gritty sub/ances to accumulate at ! insulation ( expos$ p>ts4 ,see t ! bru%es fit prop]ly & d n cut or scrat*4 ,use no em]y pap] on commutators4 ,lubricate ! commutators v sp>+ly & wipe (f z mu* ( ! lubricant z y c4 ,keep ev]y?+ ab\t ! ma*9es clean & all[ no oil dripp+s to accumulate4 ,place ! />t+ box = a motor s y c see ! motor />t f ! box4 ,always place a swit* :i* w disconnect all ( ! wires close to ! motor4 ,if possible arrange motors s !y may />t )\t load4 ,all[ no motor or g5]ator to be plac$ 9 ! op]at+ room ( a mov+-picture !at]4 ,,*apt] ,,xviii4 ,,!at] ,,wir+4 ,! wireman %\ld n fail to consult local rules or inspection dep>tm5ts z to :e!r any rules conflict ) ^? giv5 bel[4 ,he mu/ be w>n$ to consult local au?orities or rules1 too1 because safety rules are liable to *ange4 ,! purpose ( ?is *apt] is to furni% a ready ref]5ce "w conc]n+ que/ions ( electrical con/ruction 9 !at]s :i* come up daily 9 all progressive play h\ses4 ,to ?is end ! subjects h be5 arrang$ 9 alphabetical ord] & ! practical consid]ations1 z well z extracts f ! ,national ,electrical ,code gov]n+ con/ruction1 h be5 giv5 toge!r4 ,! aim has be5 to enable ! workman to f9d all in=mation conc]n+ con/ruction "w gr\p$ toge!r1 s z to obviate ! necessity ( look+ ?r\gh v>i\s p>ts ( ! book = ! in=mation s\ght4 ,?is ord] ( ?+s w probably avoid ! tr\bles n[ (t5 caus$ by ov]look+ c]ta9 po9ts t %\ld be consid]$4 ,aisle ,light4--,figure #aea is an illu/ration ( an aisle light4 ,su* lights are (t5 plac$ along /eps & aisles4 ,! light illum9ates only ! floor4 ,aisle lights %\ld be arrang$ on a sep>ate circuit & controll$ by a swit* at ! door4 ,alt]nat+ ,curr5t4--,all wires ( any circuit or ma9s or sub-ma9s ( any sy/em mu/ be run 9 ! same conduit4 ,failure to d ?is w cause an unnecess>y drop 9 voltage & heat+ ( ! conduit4 ,arc ,lamps4--,= treatm5t & con/ruction ( portable arc lamps1 see ! *apt] on 8,portable ,/age ,equipm5t04 ,p]man5tly locat$ arc lamps are us$ ab\t !at]s mo/ly = out-door light+4 ,v (t51 two or m lamps are arrang$ 9 front ( ! h\se4 ,su* lamps are mo/ly ( ! flam+ arc lamp type & are hung up high4 ,illu/ration3 ,,figure #aea4 ,9 "s ( ! *eap] !at]s a pair ( arc lamps is us$ on ! /age1 b !y d n give satisfaction4 ,! light is n ev5 & /eady en\gh & _c be prop]ly 8dimm$04 ,:]e arc lamps are to be arrang$ = /age illum9ation !y mu/ be susp5d$ amid ! sc5]y & enclos$ ) wire gu>ds4 ,9 "s cities ! use ( arc lamps susp5d$ above ! /age is prohibit$4 ,9 ! auditorium1 arc lamps are sometimes in/all$1 b ?is practice c n be recomm5d$ &1 ) ! pres5t high effici5cy inc&esc5t lamps1 !re is b little excuse = x4 ,! only advantage 9 us+ arc lamps lies 9 ! fir/ co/ ( wir+1 & ?is is m ?an balanc$ by ! difficulties ( trimm+ lamps locat$ 9 su* places4 ,:]ev] arc lamps are us$ x is ess5tial t !y be hung high & ^? t d n naturally ?r[ ! light d[nw>d mu/ be equipp$ ) suitable reflectors4 ,! "q ( drop 9 voltage ne$ n be consid]$ ) arc lamps unless runs are v long4 ,national ,electrical ,code ,rules = ,arc ,lamps4 ,arc ,lamps 9 ,g5]al4 ,mu/ be provid$ ) reliable /ops to prev5t c>bons f fall+ out 9 case ! clamps become loose4 ,all expos$ p>ts mu/ be c>efully insulat$ f ! circuit4 ,mu/1 = con/ant-curr5t sy/ems1 be provid$ ) an approv$ h& swit*1 & an automatic swit* t w %unt ! curr5t ar\nd ! c>bons1 %\ld !y fail to fe$ prop]ly4 ,! h& swit* to be approv$1 if plac$ any:]e except on ! lamps itself1 mu/ comply ) requirem5ts = swit*es on hang]-bo>ds4 ,t]m9als mu/ be design$ to secure a ?or\ghly good & p]man5t contact ) ! supply wires1 :i* contact mu/ n become loos5$ by motion ( ! lamp dur+ trimm+4 ,sp>k arre/]s mu/ s close ! upp] orifice ( ! globe t x w be impossible = any sp>ks1 ?r[n (f by ! c>bons1 to escape4 ,s]ies ,arc ,lamps4 ,mu/ be c>efully isolat$ f inflammable mat]ial4 ,mu/ be provid$ at all times ) a glass globe surr\nd+ ! arc1 & securely fa/5$ ^u a clos$ base4 ,brok5 or crack$ globes mu/ n be us$4 ,mu/ be provid$ ) a wire nett+ 7hav+ a me% n exce$+ "o & "o-f\r? in*es7 ar\nd ! globe & an approv$ sp>k arre/]1 :5 readily inflammable mat]ial is 9 ! vic9ity ( ! lamps1 to prev5t escape ( sp>ks ( c>bon or melt$ copp]4 ,outside arc lamps mu/ be susp5d$ at lea/ eight feet above sidewalks4 ,inside arc lamps mu/ be plac$ out ( rea* or suitably protect$4 ,arc lamps1 :5 us$ 9 places :]e !y are expos$ to fly+s ( easily inflammable mat]ial1 mu/ h ! electrodes enclos$ completely 9 a tight globe 9 su* mann] z to avoid ! necessity = sp>k arre/]s4 8,enclos$ arc0 lamps1 hav+ tight inn] globes may be us$1 & ! requirem5ts ( b & c above w\ld1 ( c\rse1 n apply to !m4 ,:]e hang]-bo>ds are n us$1 lamps mu/ be hung f insulat+ supports o!r ?an _! conductors4 ,lamps :5 arrang$ to be rais$ & l[]$ ei!r = c>bon+ or o!r purposes1 %all be connect$ up ) /r&$ conductors f ! la/ po9t ( support to ! lamp1 :5 su* conductor is l>g] ?an ,no4 #ad ,b4 ,s4 gauge4 ,arc ,lamps on ,con/ant-,pot5tial ,circuits4 ,mu/ h a cut-out = ea* lamp or ea* s]ies ( lamps4 ,! bran* conductors mu/ h a c>ry+ capacity ab\t fifty p] c5t 9 excess ( ! normal curr5t requir$ by ! lamp4 ,mu/ only be furni%$ ) su* resi/ances or regulators z are enclos$ 9 non-combu/ible mat]ial1 su* resi/ances be+ treat$ z s\rces ( heat4 ,inc&esc5t lamps mu/ n be us$ = ?is purpose4 ,arc ,lamps ,us$ z a ,"p ( a ,mov+-,picture ,ma*9e4 ,mu/ be con/ruct$1 s f> z practicable1 simil> to arc lamps ( !at]s1 & wir+ to same mu/ n be ( less capacity ?an ,no4 #f ,b4 ,s4 gauge4 ,see 8,portable ,/age ,equipm5t04 ,/age & ,gall]y ,pockets4 ,mu/ be ( approv$ type1 insulat$ f gr\nd & controll$ f swit*bo>d1 ea* receptacle to be ( n less ?an #ce amp]e rat+ = arc lamps nor #ae amp]es = inc&esc5t lamps1 & ea* receptacle to be wir$ to its full capacity4 ,arc pockets to be wir$ ) wire n small] ?an ,no4 #f ,b4 ,s4 gauge & inc&esc5t pockets ) n less ?an ,no4 #ab ,b4 ,s4 gauge4 ,plugs = arcs & inc&esc5t pockets mu/ n be int]*angeable4 ,armor$ ,cable4--,all wires 9 ! /age "p ( !at]s mu/ be enclos$ 9 conduit or armor$ cable4 ,armor$ cable is ?us ! only flexible conductor all[$ = p]man5t "w4 ,?is cable is v conv5i5t :]e wires mu/ be 8fi%$01 or run ar\nd beams or o!r ob/acles mak+ _m b5ds necess>y4 ,x %\ld1 h[ev]1 be us$ only :]e ! rigid conduit _c well be in/all$ & x is advisable to use ! latt]1 ev5 :]e ! additional exp5se is consid]able4 ,wires run 9 rigid conduit c be tak5 out & replac$ by new ones at any "t1 :ile ?is is n ! case ) armor$ cable4 ,%\ld a wire incas$ 9 armor$ cable develop a s]i\s fault1 ! old cable w\ld h to be ab&on$ & a new circuit run1 :i* 9 _m cases w\ld mean ! te>+ up ( p>ts ( ! build+4 ,illu/ration3 ,,figure #aeb4 ,:]e armor$ cable is to be us$ great c>e %\ld be ex]cis$ to see t b5ds are n made too %ort1 & t ea* l5g? ( cable is te/$ = gr\nds1 %ort circuits1 & op5 circuits4 ,special att5tion mu/ be giv5 to ! wires at ! place :]e ! armor has be5 cut4 ,c>eless workm5 c d great damage at ?is po9t4 ,! mann] ( cutt+ ! armor is %[n 9 ,figure #aeb4 ,ea* /r& ( ! armor is p>tly cut ) a saw & may !n be brok5 (f1 tak+ c>e t no %>p edge is left 9 position to pi]ce ! wire4 ,in/allation rules are giv5 bel[4 ,be=e in/all+ any armor$ cable1 be sure t x is ( approv$ make & gu>ante$ to pass inspection4 ,national ,electrical ,code ,rule = ,armor$ ,cables4 ,mu/ be cont9u\s f outlet to outlet or to junction boxes or cab9ets1 & ! armor ( ! cable mu/ prop]ly ent] & be secur$ to all fitt+s1 & ! entire sy/em mu/ be me*anically secur$ 9 position4 ,9 case ( s]vice connections & ma9 runs1 ?is involves runn+ su* armor$ cable cont9u\sly into a ma9 cut-out cab9et or gutt] surr\nd+ ! panel bo>d1 z ! case may be4 ,mu/ be equipp$ at e outlet ) an approv$ outlet box or plate1 z requir$ 9 conduit "w4 ,outlet plates mu/ n be us$ :]e x is practicable to in/all outlet boxes4 ,= conceal$ "w 9 walls & ceil+s compos$ ( pla/] on wood5 joi/ or /ud con/ruction1 outlet boxes or plates & also cut-out cab9ets mu/ be s in/all$ t ! front edge w n be m ?an "o-f\r? in* back ( ! f9i%$ surface ( ! pla/]1 & if ?is surface is brok5 or incomplete x %all be repair$ s t x w n %[ any gaps or op5 spaces ar\nd ! edges ( ! outlet box or plate or ( ! cut-out cab9et4 ,on wood5 walls or ceil+s1 outlet boxes or plates & cut-out cab9ets mu/ be s in/all$ t ! front edge w ei!r be flu% ) ! f9i%$ surface or project !refrom4 ,?is w n apply to conceal$ "w 9 walls or ceil+s compos$ ( concrete1 tile or o!r non-combu/ible mat]ial4 ,9 build+s already con/ruct$ :]e ! conditions are su* t nei!r outlet box nor plate c be in/all$1 ^! appliances may be omitt$ by special p]mission1 provid$ ! armor$ cable is firmly & rigidly secur$ 9 place4 ,mu/ h ! metal armor ( cables p]man5tly & effectually gr\nd$ to wat] pip+1 gas pip+1 or o!r suitable gr\nds1 provid$ t :5 connections are made to gas pip+1 !y mu/ be on ! /reet side ( ! met]4 ,if ! armor$ cable sy/em consi/s ( sev]al sep>ate sections1 ! sections mu/ be bond$ to ea* o!r1 & ! sy/em gr\nd$1 or ea* section may be sep>ately gr\nd$1 z requir$ above4 ,! armor ( cables & gas pipes mu/ be securely fa/5$ 9 outlet boxes1 junction boxes1 & cab9ets1 s z to secure good electrical connection4 ,if armor ( cables & metal ( c\pl+s1 outlet boxes1 junction boxes1 cab9ets1 or fitt+s hav+ protective coat+ ( non-conduct+ mat]ial1 su* z enamel1 are us$1 su* coat+ mu/ be ?or\ghly remov$ f ?reads ( bo? c\pl+s & ! armor ( cables1 & f surfaces ( ! boxes1 cab9ets1 & fitt+s :]e ! armor ( cables or gr\nd clamp is secur$ 9 ord] to obta9 ! requisite good connection4 ,gr\nd$ pipes mu/ be clean$ ( ru/1 scale1 etc41 at place ( atta*m5t ( gr\nd clamp4 ,connections to gr\nd$ pipes & to armor ( cables mu/ be expos$ to view or readily accessible1 & mu/ be made by means ( approv$ gr\nd clamps1 to :i* ! gr\nd wires mu/ be sold]$4 ,gr\nd wires mu/ be ( copp]1 at lea/ ,no4 #aj ,b4 ,s4 gauge 7:]e l>ge/ wire conta9$ 9 cable is n great] ?an ,no4 #j ,b4 ,s4 gauge71 & ne$ n be great] ?an ,no4 #d ,b4 ,s4 gauge 7:]e l>ge/ wire conta9$ 9 cable is great] ?an ,no4 #j ,b4 ,s4 gauge74 ,!y mu/ be protect$ f me*anical injury4 ,! gr\nd = ! armor$ cable sy/em is n to be consid]$ z a gr\nd = a second>y sy/em4 ,:5 in/all$ 9 s-call$ firepro( build+s 9 c\rse ( con/ruction1 or aft]w>ds if expos$ to moi/ure1 or :]e x is expos$ to ! wea!r1 or 9 damp places1 su* z brew]ies1 /ables1 etc41 ! cable mu/ h a lead cov]+ plac$ betwe5 ! out] braid ( ! conductors & ! /eel armor4 ,! lead cov]+ is n to be requir$ :5 ! cable is run aga9/ brick walls1 or laid 9 ord9>y pla/] walls unless same are cont9u\sly damp4 ,:]e ent]+ junction boxes1 & at all o!r outlets1 etc41 mu/ be provid$ ) approv$ t]m9al fitt+s :i* w protect ! insulation ( ! conductors f abrasion1 unless su* junction or outlet boxes are specially design$ & approv$ = use ) ! cable4 ,junction boxes mu/ always be in/all$ 9 su* a mann] z to be accessible4 ,= alt]nat+-curr5t sy/ems mu/ h ! two or m conductors ( ! circuit enclos$ 9 "o metal armor4 ,all b5ds mu/ be s made t ! armor ( ! cable w n be injur$4 ,! radius ( ! curve ( ! inn] edge ( any b5d n to be less ?an #a-a_/b in*es4 ,asbe/os4--,z all wir+ 9 !at]s is requir$ to be run 9 conduit1 & metal cab9ets are compulsory 9 ?is connection1 !re is b little opportunity to use asbe/os4 ,:]ev] ! use ( asbe/os is advisable x mu/ con=m to ! g5]al requirem5ts z giv5 = wood5 cut\t cab9ets1 viz43 8= l9+ wood5 cab9ets1 "o-eigh? in* rigid asbe/os bo>d may be us$ :5 firmly secur$ 9 place by screws or tacks04 ,atta*m5t ,plugs4--,atta*m5t plugs %\ld be us$ to connect all portable app>atus4 ,all plugs %\ld be ( approv$ type & con/ruct$ s z to pull out 9 case /ra9 is put on !m4 ,on ! /age1 p9-plug connectors %\ld be us$ 9 place ( atta*m5t plugs1 z none ( ! latt] are suffici5tly rugg$ to )/& ! h>d usage4 ,national ,electrical ,code ,rules = ,atta*m5t ,plugs4 ,l9k fuse atta*m5t plugs ( ! types n[ on ! m>ket are consid]$ unsafe1 z "u entirely possible conditions an arc may be produc$ :5 ! fuses bl[1 damag+ ! plug & p]haps caus+ fire4 ,atta*m5t plugs are n approv$ = m ?an six hundr$ & sixty watts or two hundr$ & fifty volts4 ,auditorium4--,two sep>ate sy/ems ( light+ are requir$3 ,see em]g5cy or exit light+4 ,metal m\ld+1 z well z armor$ cable or conduit1 is p]missible 9 wir+ ! auditorium "p ( ! !at]4 ,auto-,/>t]s4--,auto-/>t]s p]=m ! same s]vice ) alt]nat+-curr5t motors t resi/ances d ) direct-curr5t motors4 ,!y are us$ ) motors f two or ?ree horse p[] upw>d1 & n g5]ally ) ! small] motors4 ,! foll[+ are extracts f ! 8,national ,electrical ,code0 conc]n+ _! use3 ,9 all wet1 du/y1 or l9ty places1 auto-/>t]s1 unless equipp$ ) tight cas+s enclos+ all curr5t-c>ry+ p>ts1 mu/ be enclos$ 9 du/-tight firepro( cab9ets4 ,:]e !re is any liability ( %ort circuits1 caus$ by accid5tal contacts1 across _! expos$ live p>ts a rail+ mu/ be erect$ ar\nd !m4 ,! swit* on ! auto-/>t] mu/ provide an (f position1 a runn+ position1 & at lea/ "o />t+ position4 ,x mu/ be s arrang$ t x w be held 9 (f & runn+ position1 b n 9 />t+ position or )\t ! prop] runn+ ov]load-protection devices 9 ! circuit4 ,= curr5ts above #cj amp]es1 lugs1 into :i* ! connect+ wires may be sold]$1 or approv$ sold]less connectors mu/ be us$4 ,clamps or lugs w n be requir$ :5 leads are provid$ z a "p ( ! device4 ,! foll[+ rules are drawn = rheo/ats b may also apply to auto-/>t]s3 ,:]e ! circuit-break+ device on ! motor-/>t+ rheo/at disconnects all ( ! wires ( ! circuit1 ! swit* call$ = 9 ?is section 7to disconnect all app>atus7 may be omitt$4 ,ov]load-release devices on motor-/>t+ rheo/ats w n be consid]$ to take ! place ( ! cut\t requir$ to protect ! motor & ! rheo/at4 ,balconies4--,! illum9ation ( balconies is a difficult matt]4 ,! ceil+s "u gall]ies above are always l[1 & to obta9 ev5 illum9ation requires ! use ( _m small c&le-p[] lamps4 ,^! %\ld be set well back s z n to be visible too mu* to ! audi5ce4 ,/age-pocket capacity = "o or m arc lamps %\ld always be provid$4 ,:]e !re are gall]ies above1 ! arc lamps us$ = /age illum9ation are g5]ally plac$ !re1 b x (t5 happ5s t a mov+-picture ma*9e mu/ be in/all$ & x is v disadvantage\s if ?is mu/ be locat$ 9 ! gall]ies4 ,balconies require ! same exit & em]g5cy light s]vice z is requir$ 9 ! auditorium4 ,batt]ies4--,see ,portable ,/age ,equipm5t4 ,bells4--,sy/ems ( call bells are g5]ally arrang$ betwe5 ! box (fice or ! manag]'s (fice & ! /age swit* bo>d2 also f ! /age swit* bo>d to ! fly floor by :i* signals = rais+ & l[]+ ! curta9 may be giv52 also to ! or*e/ra lead]4 ,9 "s cities all ( ?is wir+ is requir$ to be 9 conduit4 ,^! signal+ circuits %\ld be c>efully in/all$1 = !y are z important z any "p ( ! wir+4 ,only ! v be/ bells & pu% buttons %\ld be us$1 & x is advisable to avoid ! use ( ! ord9>y annunciator wire s (t5 se5 9 connection ) bell "w4 ,num]\s diagrams & mu* in=mation conc]n+ bell wir+ is giv5 9 8,mod]n ,wir+ ,diagrams & ,descriptions01 :i* %\ld be consult$ 9 case "s complicat$ annunciator sy/em is to be in/all$4 ,figure #aec is a diagram ( a simple call-&-return-call sy/em4 ,illu/ration3 ,,figure #aec4 ,illu/ration3 ,,figure #aed4 ,bord]s4--,! numb] ( bord]s us$ 9 !at]s v>ies f "o to six1 ! latt] numb] be+ suffici5t = almo/ any /age4 ,!y are g5]ally made ( a l5g? ab\t equal to ! prosc5ium op5+4 ,! bord]s plac$ 9 ! re> are ( less importance ?an ^? 9 front & consequ5tly are made %ort] & are n provid$ ) s _m lights4 ,ea* bord] %\ld h at lea/ ?ree circuits1 "o = ea* color2 ea* circuit be+ tak5 ?r\gh a sep>ate dimm] s t any color may be us$ alone & dimm$ z desir$4 ,figures #aed & #aee %[ types ( bord]s1 & ! me?od ( wir+ is %[n 9 ,figure #aef4 ,illu/ration3 ,,figure #aee4 ,illu/ration3 ,,figure #aef4 ,l>ge bord]s are v heavy & are usually susp5d$ by wire rope & provid$ ) c\nt]weights to make h&l+ easy4 ,! wire rope %\ld be kept well protect$ by oil+2 ! moi/ure giv5 (f by firepro($ sc5]y is liable to ru/ !m v fa/1 & z ! ropes are made up ( v f9e /r&s ! ru/ soon cuts entirely ?r\gh !m4 ,! susp5d+ ropes & also cables supply+ lights mu/ be long en\gh to admit ( br++ ! bord] )9 five or six feet ( ! /age floor = lamp r5ewals & clean+4 ,! clean+ is v important z ! du/ :i* accumulates may absorb a l>ge "p ( ! light4 ,! ,national ,electrical ,code ,rules ,gov]n+ ,bord] & ,prosc5ium ,sidelight ,con/ruction4 ,mu/ be con/ruct$ ( /eel ( a ?ickness n less ?an ,no4 #bj ,u4 ,s4 %eet metal gauge2 treat$ to prev5t oxidation2 be suitably /ay$ & support$2 & s design$ t flanges ( reflectors w protect lamps4 ,mu/ be s wir$ t no set ( lamps requir+ m ?an #a1cbj watts nor m ?an #bf receptacles %all be dep5d5t ^u "o cut-out4 ,mu/ be wir$ 9 approv$ conduit or armor$ cable1 ea* lamp receptacle to be enclos$ )9 an approv$ outlet box1 or ! lamp receptacles may be m\nt$ 9 an iron or /eel box1 metal to be ( a ?ickness n less ?an ,no4 #bj ,u4 ,s4 %eet metal gauge treat$ to prev5t oxidation1 s con/ruct$ z to enclose all wires4 ,wires to be sold]$ to lugs ( receptacles4 ,mu/ be provid$ ) suitable gu>ds to prev5t sc5]y or o!r combu/ible mat]ial com+ 9 contact ) lamps4 ,cable = bord]s mu/ be ( approv$ type & suitably support$2 conduit con/ruction mu/ be us$ f swit*bo>d to po9t :]e cables mu/ be flexible to p]mit ( ! rais+ & l[]+ ( bord]4 ,= ! wir+ ( ! bord] prop]1 wire ) approv$ sl[-burn+ insulation mu/ be us$4 ,bord]s mu/ be suitably susp5d$1 & if a wire rope is us$ same mu/ be insulat$ by at lea/ "o /ra9 insulator ins]t$ at ! bord]4 ,box ,(fice4--,! box (fice is (t5 a v /uffy place 9 summ] & v cold 9 w9t]4 ,!re %\ld be an outlet = a fan motor1 & also "o = a heat]4 ,v _m box (fices dep5d ^u electric heat+ = com=t 9 w9t]4 ,pl5ty ( light %\ld be provid$ & ! light %\ld be at ! ceil+1 out ( ! way1 & directly ov] ! ticket w9d[4 ,brackets4--,any brackets us$ 9 !at]s %\ld be at lea/ sev5 feet above ! floor4 ,brackets us$ = em]g5cy or exit lights mu/ be fitt$ ) keyless sockets4 ,see 8,fixtures04 ,bran* ,circuits4--,! t]m1 8bran* circuit01 z "h us$ ref]s to ! wires leav+ ! la/ cut-outs & connect+ directly to ! lamps or o!r devices4 ,ma9s are (t5 run f ! swit*bo>d to v>i\s p>ts ( ! build+ to fe$ cut-out c5t]s1 & ! bran* circuits are !n run f ^! c5t]s4 ,?is is (t5 ! *eape/ me?od1 b x is by no means ! be/4 ,9 a well design$ !at] all bran* circuits lead out f ! vic9ity ( ! swit*bo>d s t1 9 case ( any tr\ble ) fuses1 !y may be replac$ )\t int]f]+ ) any "p ( ! audi5ce & 9 ! %orte/ possible "t4 ,?is me?od ( wir+ involves "s long runs ( bran* circuit wires & ,table ,v1 :i* %[s ! drop 9 voltage1 0 prep>$ = ! conv5i5ce ( wirem54 ,if possible ! circuits %\ld be s arrang$ t ! lamps f$ are closely toge!r s all may receive ne>ly ! same voltage4 ,! drop %\ld n mu* exce$ two p] c5t4 ,table %[+ drop 9 voltage due to #f amp]es1 ) sizes ( wire & di/ances giv53 ,,table ,v4 ,,drop ,,9 ,,voltage ,,due ,,to #f ,,amp]es ,,) ,,size ,,( ,,wire ,,& ,,di/ance ,,giv54 ---------------------------------------- ------------------ ,di/ance #ej #ge #ajj #abe #aej #age #bjj #bbe #bej #cjj 9 feet ---------------------------------------- ------------------ ,size ( ,wire #a4eh #b4cg #c4af #c4ie #d4gd #e4ec #f4cb #g4aa #g4ij #i4dh ,no4 #ad ---------------------------------------- ------------------ ,size ( ,wire #j4ii #a4dh #a4ih #b4dg #b4ig #c4de #c4if #d4de #d4ie #e4id ,no4 #ab ---------------------------------------- ------------------ ,size ( ,wire #j4fc #j4id #a4be #a4ef #a4hg #b4ai #b4ej #b4ha #c4ab #c4ge ,no4 #aj ---------------------------------------- ------------------ ,size ( ,wire #j4ci #j4ei #j4gh #j4ig #a4ag #a4cf #a4ef #a4ge #a4ie #b4cd ,no4 #h ---------------------------------------- ------------------ ,national ,electrical ,code ,rules ,gov]n+ ,size ( ,wire = ,bran* ,circuits & ,fuses = ,same4 ,no wire small] ?an ,no4 #ad ,b4 ,s4 gauge mu/ be us$4 ,ea* bran* circuit mu/ be protect$ by fuses1 :i* mu/ be s plac$ t no set ( small motors1 small heat+ devices1 or inc&esc5t lamps1 :e!r gr\p$ on "o fixture or on sev]al fixtures or p5dants 7nor m ?an #af sockets or receptacles7 requir+ m ?an #ffj watts1 w be dep5d5t ^u "o cut-out4 ,by special p]mission1 9 cases :]e wir+ equal 9 size & insulation to ,no4 #ad ,b4 ,s4 gauge approv$ rubb]-cov]$ wire is c>ri$ direct into keyless sockets or receptacles1 & :]e ! location ( sockets & receptacles is su* z to r5d] unlikely ! atta*m5t ( flexible cords !reto1 ! circuits may be s arrang$ t n m ?an #a1cbj watts 7or ?irty-two sockets or receptacles7 w be dep5d5t ^u ! f9al cut-out4 ,except = signs & outl9e light+1 sockets & receptacles w be consid]$ z requir+ n less ?an #dj watts ea*4 ,all bran*es or taps1 f any ?ree-wire sy/em1 :i* are directly connect$ to lamp sockets or o!r translat+ devices1 mu/ be run z two-wire circuits if ! fuses are omitt$ 9 ! neutral1 or if ! diff]5ce ( pot5tial betwe5 ! two outside wires is ov] #bej volts1 & bo? wires ( su* bran* or tap circuits mu/ be protect$ by prop] fuses4 ,! above %all also apply to motors1 except t small motors may be gr\p$ "u ! protection ( a s+le set ( fuses1 provid$ ! rat$ capacity ( ! fuses does n exce$ #aj amp]es4 ,:5 #a1cbj watts are dep5d5t ^u "o fusible cut-out1 z is all[$ 9 !at] wir+1 outl9e light+ & l>ge *&eli]s1 ! fuses may be 9 accordance ) ! foll[+3 #abe volts or less #bj amp]es #abe to #bej volts #aj amp]es ,bus-,b>s4--,bus-b>s may be made ( b>e metal4 ,!y mu/1 h[ev]1 be protect$ aga9/ accid5tal contact4 ,! metal %\ld be ample s t x w n heat m ?an #ej degrees ,fahr5heit above ! surr\nd+ air4 ,x is cu/om>y to calculate ! metal ne$$1 on ! basis ( #a1jjj amp]es p] squ>e-in* cross section4 ,on ?is basis b>s ( ! sizes giv5 bel[ w\ld h ! c>ry+ capacities 9 amp]es giv5 9 ! body ( ! table4 ,,table ,,vi4 ,,curr5t-,,c>ry+ ,,capacity ,,( ,,bus-,,b>s4 ---------------------------------------- ------------------ ,?ickness #b_/cbc_/cbd_/cbe_/cbf_/cbg_/cbh_/cbi_/c baj_/cbab_/cbaf_/cb ---------------------------------------- ----------------- #a_/b #cj #de #fj #ge #ij #aje #abj #ace #aej #afe #ahj ---------------------------------------- ------------ #e_/h #cg #eg #ge #id #ajh #acb #aej #afh #ahh #bjf #bbe ---------------------------------------- ------------ #f_/h #de #fh #ij #aab #ace #aeh #ahj #bjb #bbe #bdh #bgj ---------------------------------------- ------------ ,wid? #g_/h #ec #gi #aje #acj #aeh #ahd #baj #bcf #bfc #bhi #cae ---------------------------------------- ------------ 9 #a4j #fj #ij #abj #aej #ahj #baj #bdj #bgj #cjj #ccj #cfj ---------------------------------------- ------------ ,9- #a-a_/d #ge #aab #aej #ahh #bbe #bfc #cjj #cch #cge #dab #dej *es ---------------------------------------- ------------ #a-a_/b #ij #ace #ahj #bbe #bgj #cae #cfj #dje #dej #die #edj ---------------------------------------- ------------ #a-c_/d #aje #aeg #baj #bfc #cae #cfg #dbj #dgc #ebe #egg #fcj ---------------------------------------- ------------ #b4jj #abj #ahj #bdj #cjj #cfj #dbj #dhj #edj #fjj #ffj #gbj ---------------------------------------- ------------ #c4jj #ahj #bgj #cfj #dej #edj #fcj #gbj #haj #ijj #iij #ajhj ---------------------------------------- ----------------- ,cab9ets4--,cab9ets are requir$ to enclose all fuses4 ,x is advis$ t !y be arrang$ s t x w n be necess>y to op5 ! fuse comp>tm5t to op]ate swit*es4 ,c>e %\ld be ex]cis$ 9 locat+ cut-out cab9ets4 ,!y %\ld be 9 a dry place1 easily accessible to au?oriz$ p]sons1 & n accessible to ! g5]al public or miscellane\s employes4 ,if too accessible !y are likely to be made receptacles = all sorts ( rubbi%4 ,wood5 or composition cab9ets mu/ n be us$ 9 !at]s4 ,use only approv$ cab9ets4 ,9 "s cities special rules1 gov]n+ ! con/ruction ( cab9ets = !at]s1 exi/ & ^! %\ld be look$ up4 ,cables4--,= con/ruction rules1 see 8,/age ,cables0 9 ! *apt] on 8,portable ,/age ,equipm5t04 ,cables are requir$ to connect bord] lights4 ,! cable is usually run f an outlet on ! grid floor above ! c5t] ( ! bord]4 ,x mu/ be long en\gh to all[ ! bord] to be l[]$ = ! clean+ & r5ewal ( lamps4 ,! slack cable mu/ be tak5 up :5 ! bord] is rais$ & "s provision mu/ be made to support ! cable )\t injury to ! insulation4 ,wire ropes or cables are g5]ally us$ to support ! bord]s1 b ! l[] end1 :i* is h&l$ by ! /age crew1 is ( ord9>y manilla rope4 ,wire cables mu/ be insulat$ f ! bord] by /ra9 insulators4 ,canopies4--,v _m !at]s are provid$ ) canopies :i* ext5d ov] ! /reet4 ,sometimes ^! are fitt$ out ) glass signs beh9d :i* inc&esc5t lamps are in/all$4 ,(t51 also1 a r[ ( lights is arrang$ ar\nd ! bottom ( ! canopy ceil+4 ,! numb] ( lights to be us$ dep5ds ^u ! design ( ! canopy1 b ! effect is be/ if a l>ge numb] ( small c&le-p[] lamps are us$4 ,^! lamps %\ld be ( l[ intr9sic brilliancy4 ,if possible1 ! lamps & sockets %\ld be arrang$ to be out ( ! wea!r4 ,9 addition to ! small outl9e lamps1 o!r lights are (t5 plac$ "u canopy to provide bright illum9ation4 ,ea* circuit may c>ry #a1cbj watts4 ,national ,electrical ,code ,rule4 ,:]e insulat+ jo9ts are requir$1 fixture canopies ( metal mu/ be ?or\ghly & p]man5tly insulat$ f metal walls or ceil+s1 or f pla/] walls or ceil+s on metal la?+1 & f outlet boxes4 ,canopy insulators mu/ be securely fa/5$ 9 place1 s z to sep>ate ! canopies ?or\ghly & p]man5tly f ! surfaces & outlet boxes f :i* !y are design$ to be insulat$4 ,c>riage ,call4--,see 8,program ,bo>d04 ,c>ry+ ,capacity ( ,wires4--,table ,,vii is design$ to help ! wirem5 select ! prop] size ( wire to use 9 supply+ a c]ta9 numb] ( lights4 ,! fir/ column at ! left gives ! ,b4 ,s4 gauge numb]4 ,! second column gives ! numb] ( amp]es all[$ on ea* wire accord+ to ! ,national ,electrical ,code4 ,! ?ird column gives ! di/ance 9 feet :i* w cause a loss ( #b volts ) ! curr5t giv52 ?us a curr5t ( #gj amp]es 9 a ,no4 #d ,b4 ,s4 gauge wire w lose #b volts ov] a di/ance ( #ef feet4 ,! prop] size ( wire to be us$ c easily be det]m9$ f ! table4 ,! loss w always be 9 proportion to ! product ( di/ance & curr5t4 ,! balance ( ! table is devot$ to %[+ ! numb] ( watts & lamps ( v>i\s sizes ! wires w be all[$ to supply4 ,ceil+ ,fans4--,mu/ be hung f insulat$ hooks1 or else !re mu/ be an insulator int]pos$ betwe5 ! motor & its support4 ,n m ?an #ffj watts may be on "o circuit4 ,*&eli]s4--,l>ge & elaborate *&eli]s are sometimes us$ 9 ! c5t] ( ! auditorium ceil+ = purposes ( illum9ation4 ,su* *&eli]s %\ld be susp5d$ 9 a mann] :i* w admit ( readily rais+ or l[]+ !m = lamp+ up or repairs4 ,= rules gov]n+ wir+1 see 8,fixtures04 ,,table ,,vii4 ,,table ,,%[+ ,,c>ry+ ,,capacity ,,( ,,wires2 ,,di/ance ,,to ,,:i* ,,full ,,load ,,may ,,be ,,c>ri$ ,,at #b ,,volts ,,drop ,,& ,,numb] ,,( ,,lights ,,equival5t ,,to ,,full ,,curr5t ,,giv54 ,b4 ,s4,rubb] ,di/ance ,total ,total ,numb] ( ,lamps ( ,gage ,insu- 9 ,feet ,capacity 9 ,diff]5t ,voltages & lation ,caus+ ,watts ,wattages t may be suppli$ ,amp]esa ,loss --------------------------- ( #b #be-,watt #dj-,watt #fj-,watt ,volts ----------------------------------- #aaj #bbj #aaj #bbj #aaj #bbj #aaj #bbj ,v4 ,v4 ,v4 ,v4 ,v4 ,v4 ,v4 ,v4 ---------------------------------------- ----------------- #ad #ae #bf #afej #ccjj #ff #acb #da #hb #bg #ed #ab #bj #cj #bbjj #ddjj #hh #agf #ee #aaj #cf #gc #aj #be #ch #bgej #eejj #aaj #bbj #fh #acg #df #ia #h #ce #dc #chej #ggjj #aed #cjh #if #aib #fd #abh #f #ej #ej #eejj #aajjj #bbj #ddj #acg #bge #ia #ahc #e #ee #ef #fjej #abajj #bdb #dhd #aea #cjb #ajj #bja #d #gj #ef #ggjj #aedjj #cjh #faf #aib #che #abh #bef #c #hj #fa #hhjj #agfjj #ceb #gjd #bbj #ddj #adf #bib #b #ij #fh #iijj #aihjj #cif #gib #bdg #did #afe #ccj #a #ajj #fg #aajjj #bbjjj #ddj #hhj #bge #eej #ahc #cff #j #abe #gh #acgej #bgejj #eejaajj #cdc #fhf #bbi #deh #jj #aej #hb #afejj #ccjjj #ffjacbj #dab #hbd #bge #eej #jjj #age #hi #aibej #chejj #ggjaedj #dha #ifb #cbj #fdj #jjjj #bbe #hg #bdgej #diejj #iijaihj #fahabcf #dab #hbd #bjjjjj #bjj #ib #bbjjj #ddjjj #hhjagfj #eejaajj #cfg #gcd #cjjjjj #bge #aja #cjbej #fjejjabajbdbj #gefaeab #ejdajjh #djjjjj #cbe #aad #cegej #gaejjadcjbhfj #hicaghf #eifaaib #ejjjjj #djj #aag #ddjjj #hhjjjagfjcebjaajjbbjj #gccadee #fjjjjj #dej #abc #diejj #iijjjaihjcifjabcgbdgd #hbeafej #gjjjjj #ejj #acj #eejjjaajjjjbbjjddjjacgebgej #iafahcb #hjjjjj #eej #ace #fjejjabajjjbdbjdhdjaeabcjbdajjhbjaf #ijjjjj #fjj #aci #ffjjjacbjjjbfdjebhjafejccjjaajjbbjj #ajjjjjj #fej #adc #gaejjadcjjjbhfjegbjaghgcegdaaiabchb #aajjjjj #fij #adg #geijjaeahjjcjcffjgbahigcgidabfdbebh #abjjjjj #gcj #aea #hjcjjafjfjjcbabfdbdbjjgdjadacchbfgf #acjjjjj #ggj #aee #hdgjjafidjjcchhfggfbaagdbcdadabbhbd #adjjjjj #haj #afa #hiajjaghbjjcefdgabhbbbgddedadhebigj #aejjjjj #hej #afd #icejjahgjjjcgdjgdhjbccgdfgdaeehcaaf ---------------------------------------- ----------------- ,rubb] ,di/ance ,total ,total ,numb] ( ,lamps ( ,insu- 9 ,feet ,capacity 9 ,diff]5t ,voltages & ,b4 ,s4lation ,caus+ ,watts ,wattages t may be suppli$ ,gage ,amp]esa ,loss --------------------------- ( #b #ajj-,watt#aej-,watt#bej-,watt ,volts ----------------------------------- #aaj #bbj #aaj #bbjaaj #bbjaajbbj ,v4 ,v4 ,v4 ,v4 ,v4 ,v4 ,v4 ,v4 ---------------------------------------- ----------------- #ad #ae #bf #afej #ccjj #af #cc #aa #bb #f #ac #ab #bj #cj #bbjj #ddjj #bb #dd #ad #bi #h #ag #aj #be #ch #bgej #eejj #bg #ee #ah #cf #aa #bb #h #ce #dc #chej #ggjj #ch #gg #be #fa #ae #cj #f #ej #ej #eejj #aajjj #ee #aaj #cf #gc #bb #dd #e #ee #ef #fjej #abajj #fj #aba #dj #hj #bd #dh #d #gj #ef #ggjj #aedjj #gg #aed #di #ii #cj #fa #c #hj #fa #hhjj #agfjj #hh #agf #eh #aag #ce #gj #b #ij #fh #iijj #aihjj #ii #aih #ff #acb #ci #gh #a #ajj #fg #aajjj #bbjjjaaj #bbj #gc #adf #dd #hh #j #abe #gh #acgej #bgejjacg #bgd #ia #ahb #eeaaj #jj #aej #hb #afejj #ccjjjafe #ccjaaj #bbj #ffacb #jjj #age #hi #aibej #chejjaib #chdabh #bef #ggaed #jjjj #bbe #hg #bdgej #diejjbdg #djdafe #ccj #iiaih #bjjjjj #bjj #ib #bbjjj #ddjjjbbj #ddjadf #bib #hhagf #cjjjjj #bge #aja #cjbej #fjejjcjb #fjdbja #djbababdb #djjjjj #cbe #aad #cegej #gaejjceg #gadbch #dgfadcbhf #ejjjjj #djj #aag #ddjjj #hhjjjddj #hhjbic #ehfagfceb #fjjjjj #dej #abc #diejj #iijjjdie #iijccj #ffjaihcif #gjjjjj #ejj #acj #eejjjaajjjjeejaajjcff #gcbbbjddj #hjjjjj #eej #ace #fjejjabajjjfjeabajdjc #hjfbdbdhd #ijjjjj #fjj #aci #ffjjjacbjjjffjacbjddj #hhjbfdebh #ajjjjjj #fej #adc #gaejjadcjjjgaeadcjdgf #iebbhfegb #aajjjjj #fij #adg #geijjaeahjjgeiaeahejfajabcjcfjf #abjjjjj #gcj #aea #hjcjjafjfjjhjcafjfeceajgjcbafdb #acjjjjj #ggj #aee #hdgjjafidjjhdgafidefdaabhcchfgf #adjjjjj #haj #afa #hiajjaghbjjhiaaghbeidaahhcefgab #aejjjjj #hej #afd #icejjahgjjjiceahgjfbcabdfcgdgdh ---------------------------------------- ----------------- ,national ,electrical ,code ,rules = ,fus+ ,*&eli] ,circuits4 ,:5 #a1cbj watts are dep5d5t ^u "o cut-out1 z is all[$ 9 !at] wir+1 outl9e light+1 & l>ge *&eli]s1 ! fuse may be 9 accordance ) ! foll[+3 #abe volts or less #bj amp]es #abe to #bej volts #aj amp]es ,circuit ,break]s4--,circuit break]s are n us$ mu* ab\t !at]s4 ,!y are us$ mo/ly 9 connection ) motors & on swit*bo>ds ( isolat$ plants4 ,!y are m s5sitive & quick] to act ?an fuses &1 9 case ( a bl[-out1 c be m easily replac$4 ,:]e circuit break]s are us$ x is good practice to set !m = a high] amp]age ?an ! fuses s t1 9 case ( a heavy %ort circuit1 ! break] may act :ile ! fuse w take c>e ( an ov]load :i* comes on m gradually4 ,national ,electrical ,code ,rides = ,circuit ,break]s4 ,) motors an automatic circuit break]1 disconnect+ all wires ( ! circuit1 may s]ve z bo? swit* & cut-out4 ,:]e ! circuit-break+ device on ! motor-/>t+ rheo/at disconnects all wires ( ! circuit1 ! swit* may be omitt$4 ,circuit break]s mu/ n be set m ?an ?irty p] c5t above ! all[able c>ry+ capacity ( ! wires1 unless a fusible cut-out is also in/all$ on ! circuit4 ,:5 in/all$ )\t o!r automatic ov]load protective devices1 automatic ov]load circuit break]s mu/ h ! poles & trip coils s arrang$ z to af=d complete protection aga9/ ov]loads & %ort circuits &1 if also us$ 9 place ( ! swit*1 mu/ be s arrang$ t no "o pole c be op5$ manually )\t disconnect+ all ! wires4 ,conceal$ ,"w4--,all conceal$ "w mu/ be 9 conduit or armor$ cable4 ,:]ev] possible1 rigid conduit %\ld be us$4 ,armor$ cable %\ld be us$ only :]e ! :ole cable may at any "t be )drawn1 or :]e x is impracticable to use rigid conduit4 ,conduit ,"w4--,?is is n[ consid]$ ! /&>d me?od ( con/ruction4 ,x is1 h[ev]1 some:at ov]-rat$ &1 especially 9 wet places1 has l$ to mu* disappo9tm5t4 ,x is g5]ally recogniz$ t wires1 plac$ 9 conduit1 w cause m tr\ble ?an ^? plac$ 9 any o!r /&>d mann]4 ,! tr\ble is1 h[ev]1 conf9$ to ! int]ior ( ! conduit &1 if ! conduit sy/em be kept 9 good ord]1 & fuses at _! prop] limit1 !re is no *ance ( fire f ! wire conf9$ )9 ! conduit4 ,!re are ?ree po9ts :i*1 if c>efully obs]v$1 w avoid mo/1 if n all1 ( ! conduit tr\bles3 ,avoid z f> z possible locat+ conduit 9 wet or damp places4 ,run all conduits s t !y w dra94 ,give p>ticul> att5tion to jo9ts 9 outlet or junction boxes2 tape !m heavily2 & arrange !m s !y are n press$ aga9/ metal m ?an is necess>y2 use l>ge boxes4 ,wires us$ 9 conduits mu/ h approv$ rubb] insulation & d\ble braid4 ,national ,electrical ,code ,rules = ,wires & ,int]ior ,conduits4 ,wires = ,conduit ,"w4 ,mu/ h an approv$ rubb] insulat$ cov]+ 7,type ,lett] ,r4 ,d471 & mu/ )9 ! conduit tub+ be )\t splices or taps4 ,mu/ n be drawn 9 until all me*anical "w on ! build+ has be51 z f> z possible1 complet$4 ,conductors 9 v]tical conduit ris]s mu/ be support$ )9 ! conduit sy/em 9 accordance ) ! foll[+3 ,no4 #ad to #j e #ajj feet ,no4 #jj to #jjjj e #hj feet ,no4 #jjjj to #cej1jjj ,c4 ,m4 e #fj feet #cej1jjj ,c4 ,m4 to #ejj1jjj ,c4 ,m4 e #ej feet #ejj1jjj ,c4 ,m4 to #gej1jjj ,c4 ,m4 e #dj feet #gej1jjj ,c4 ,m4 e #ce feet ,! foll[+ me?ods ( support+ cables are recomm5d$3 7#a7 ,a turn ( #ij degrees 9 ! conduit sy/em w con/itute a satisfactory support4 7#b7 ,junction boxes may be ins]t$ 9 ! conduit sy/em at ! requir$ int]vals1 9 :i* insulat+ supports ( approv$ type mu/ be in/all$ & secur$ 9 a satisfactory mann] s z to )/& ! weight ( ! conductors atta*$ !reto1 ! boxes to be provid$ ) prop] cov]s4 7#c7 ,cables may be support$ 9 approv$ junction boxes on two or m insulat+ supports s plac$ t ! conductors w be deflect$ at an angle ( n less ?an #ij degrees1 & c>ri$ a di/ance ( n less ?an twice ! diamet] ( ! cable f its v]tical position4 ,cables s susp5d$ may be additionally secur$ to ^! insulators by tie wires4 ,o!r me?ods may be us$ if specially approv$4 ,mu/1 = alt]nat+-curr5t sy/ems1 h two or m wires ( a circuit drawn 9 ! same conduit4 ,x is sugge/$ t ?is be done = direct-curr5t sy/ems1 also1 s t !y may be *ang$ to alt]nat+ sy/ems at any "t1 induction tr\bles prev5t+ su* a *ange if ! wires are 9 sep>ate conduits4 ,except 9 ! case ( /age pocket & bord] circuits ! same conduit mu/ n conta9 m ?an f\r two-wire1 or ?ree ?ree-wire circuits ( ! same sy/em1 except by special p]mission1 & mu/ nev] conta9 circuits ( diff]5t sy/ems4 ,int]ior ,conduits4 ,no conduit small] ?an "o-half in* electrical-trade size %all be us$4 ,mu/ be cont9u\s f outlet to outlet or to junction boxes or cab9ets1 & ! conduit mu/ prop]ly ent]1 & be secur$ to all fitt+s & ! entire sy/em mu/ be me*anically secur$ 9 position4 ,9 case ( s]vice connections & ma9 runs1 ?is involves runn+ ea* conduit cont9u\sly into a ma9 cut-out cab9et or gutt] surr\nd+ ! panel bo>d1 z ! case may be4 ,dep>ture f ?is rule may be au?oriz$ 9 case ( und]gr\nd s]vices by special p]mission4 ,mu/ be fir/ in/all$ z a complete conduit sy/em1 )\t ! conductors4 ,mu/ be equipp$ at e outlet ) an approv$ outlet box or plate4 ,at expos$ ends ( conduit 7b n at fixture outlets71 :]e wires pass f ! conduit sy/em )\t splice1 jo9t1 or tap1 an approv$ fitt+1 hav+ sep>ately bu%$ holes = ea* conductor1 mu/ be us$4 ,dep>ture f ?is rule may be au?oriz$ by special p]mission4 ,outlet plates mu/ n be us$ :]e x is practicable to in/all outlet boxes4 ,= conceal$ "w 9 walls & ceil+s compos$ ( pla/] on wood5 joi/ or /ud con/ruction1 outlet boxes or plates1 & also cut-out cab9ets mu/ be s in/all$ t ! front edge w n be m ?an "o-f\r? in* back ( ! f9i%$ surface ( ! pla/]2 & if ?is surface is brok5 or incomplete x %all be repair$ s t x w n %[ any gaps or op5 spaces ar\nd ! edges ( ! outlet box or plate or ( ! cut-out cab9et4 ,on wood5 walls or ceil+s1 outlet boxes or plates & cut-out cab9ets mu/ be s in/all$ t ! front edge w ei!r be flu% ) ! f9i%$ surface or project !refrom4 ,?is w n apply to conceal$ "w 9 walls or ceil+s compos$ ( concrete1 tile or o!r non-combu/ible mat]ial4 ,9 build+s already con/ruct$ :]e ! conditions are su* t nei!r outlet box or plate c be in/all$1 ^! appliances may be omitt$1 provid+ ! conduit ends are bu%$ & secur$4 ,x is sugge/$ t outlet boxes & fitt+s1 hav+ conductive coat+s1 be us$ 9 ord] to secure bett] electrical contact at all po9ts ?r\gh ! conduit sy/em4 ,metal conduits1 :]e !y ent] junction boxes & at all o!r outlets1 etc41 mu/ be provid$ ) approv$ bu%+s or fa/5+ plates fitt$ s z to protect wire f abrasion1 except :5 su* protection is obta9$ by ! use ( approv$ nipples1 prop]ly fitt$ 9 boxes or devices4 ,mu/ h ! metal ( ! conduit p]man5tly & effectually gr\nd$ to wat] pip+1 gas pip+1 or o!r suitable gr\nds1 provid$ t :5 connections are made to gas pip+1 !y mu/ be on ! /reet side ( ! met]4 ,if ! conduit sy/em consi/s ( sev]al sep>ate sections1 ! sections mu/ be bond$ to ea* o!r1 & ! sy/em gr\nd$2 or ea* section may be sep>ately gr\nd$1 z requir$ above4 ,:]e %ort sections ( conduit 7or pipe ( equival5t /r5g?7 are us$ = ! protection ( expos$ wir+ on side walls1 & su* conduit or pipe & wir+ is in/all$ z requir$ by ! ,code ,rules1 ! conduit or pipe ne$ n be gr\nd$4 ,conduits & gas pipes mu/ be securely fa/5$ 9 outlet boxes1 junction boxes1 & cab9ets1 s z to secure good electrical connections4 ,if conduits1 c\pl+s1 outlet boxes1 junction boxes1 cab9ets or fitt+s1 hav+ protective coat+ ( non-conduct+ mat]ial su* z enamel1 are us$1 su* coat+ mu/ be ?or\ghly remov$ f ?reads ( bo? c\pl+s & conduit1 & su* surfaces ( boxes1 cab9ets1 & fitt+s1 :]e ! conduit or gr\p clamp is secur$1 9 ord] to obta9 ! requisite good connection4 ,gr\nd$ pipes mu/ be clean$ ( ru/1 scale1 etc41 at place ( atta*m5t ( gr\nd clamp4 ,connections to gr\nd$ pipes & to conduits mu/ be expos$ to view or readily accessible1 & mu/ be made by means ( approv$ gr\nd clamps to :i* ! gr\nd wires mu/ be sold]$4 ,gr\nd wires mu/ be ( copp]1 at lea/ ,no4 #aj ,b4 ,s4 gauge 7:]e l>ge/ wire conta9$ 9 conduit is n great] ?an ,no4 #j ,b4 ,s4 gauge71 & ne$ n be great] ?an ,no4 #d ,b4 ,s4 gauge 7:]e l>ge/ wire conta9$ 9 conduit is great] ?an ,no4 #j ,b4 ,s4 gauge74 ,!y %all be protect$ f me*anical injury4 ,! gr\nd on ! conduit sy/em is n to be consid]$ z a gr\nd = a second>y sy/em4 ,junction boxes mu/ always be in/all$ 9 su* a mann] z to be accessible4 ,all elb[s or h&s mu/ be s made t ! conduit w n be injur$4 ,! radius ( ! curve ( ! inn] edge ( any elb[ mu/ n be less ?an ?ree & "o-half in*es1 & mu/ h n m ?an ! equival5t ( f\r qu>t] b5ds f outlet to outlet1 ! b5ds at ! outlets n be+ c\nt$4 ,contacts4--,mu/ be m\nt$ on non-combu/ible non-absorption insulat$ bases4 ,o!r mat]ials ?an slate1 m>ble1 or porcela9 mu/ be submitt$ = special exam9ation be=e be+ us$4 ,cord4--,! use ( flexible cord %\ld be r$uc$ to a m9imum4 ,:]ev] drop lights are necess>y !y %\ld be wir$ ) re9=c$ cord or /age cable4 ,curr5t ,taps4--,mu/ be ( approv$ con/ruction & may be us$ if prop]ly in/all$4 ,national ,electrical ,code ,rules = ,curr5t ,taps4 ,:]e1 9 addition to sockets or receptacles already in/all$1 connections are desir$ to light+ circuits = portable lamps1 = motors1 or o!r special appliances requir+ only small am\nts ( curr5t1 multiple-curr5t taps may be us$1 provid$ ! entire circuit does n require m ?an #ffj watts1 & provid$ _! use w n1 "u any conditions1 involve a dep>ture f ! requirem5ts ( ,rule #bc-;d ( ! ,national ,electrical ,code4 ,curr5t taps mu/ n be us$ 9 key or pull sockets if ! device1 controll$ ?r\gh su* sockets1 requires m ?an #bej watts4 ,cut-,outs4--,all cut-outs %\ld be on ! /age swit*bo>d4 ,?is requires consid]able extra wire1 b x w be pr(itable 9 ! end4 ,fuses %\ld be inspect$ occasionally to see t contacts are bright & screws kept tight4 ,!re is ev]y:]e a v /rong t5d5cy to ov]-fuse1 & ! pr9cipal reason = x is ! failure to keep screws tightly fa/5$4 ,!re is no fuse bett] ?an ! plug fuse b x is n p]mitt$ ) voltages high] ?an #abe or ) m ?an #cj amp]es4 ,refillable fuses mu/ n be us$4 ,c>tridge fuses1 especially1 require to be kept clean4 ,! spr+ contacts on ^! (t5 gr[ weak & cause heat+ :i* helps to bl[ ! fuse4 ,! neutral fuse 9 ?ree-wire in/allations %\ld be l>g] ?an ! outside fuses4 ,l9k fuses %\ld be avoid$ on acc\nt ( ! delay t may be caus$ ?r\gh difficulty ( in/all+4 ,x is advisable n to place swit*es 9 ! same cab9et ) fuses4 ,national ,electrical ,code ,rules = ,automatic ,cut-outs 7,fuses & ,circuit-,break]s74 ,con/ant-,pot5tial ,sy/ems4 ,mu/ be plac$ on all s]vice wires1 ei!r ov]head or und]gr\nd1 9 ! ne>e/ accessible place to ! po9t :]e !y ent] ! build+1 inside ! walls1 & arrang$ to cut (f ! entire curr5t f ! build+4 ,dep>ture f ?is rule may be au?oriz$ only "u special p]mission 9 writ+4 ,:]e ! s]vice swit* is inside ! build+1 ! cut-out requir$ by ?is section mu/ be plac$ s z to protect x4 ,= ?ree-wire 7n ?ree-phase7 sy/ems ! fuse 9 ! neutral wire may be omitt$1 provid$ ! neutral wire is ( equal c>ry+ capacity to ! l>g] ( ! outside wires & is gr\nd$4 ,mu/ be plac$ at e po9t :]e a *ange is made 9 ! size ( wire 7unless ! cut-out 9 ! l>g] wire w protect ! small]74 ,= ?ree-wire direct curr5t or s+le-phase sy/ems ! fuse 9 ! neutral wire1 except t call$ = "u ,section d1 may be omitt$1 provid$ ! neutral wire is gr\nd$4 ,mu/ be 9 pla9 sight1 or enclos$ 9 an approv$ cab9et1 & readily accessible4 ,!y mu/ n be plac$ 9 ! canopies or %ells ( fixtures4 ,l9k fuses may be us$ only :5 m\nt$ on approv$ bases & mu/ be enclos$ 9 du/-tight1 firepro($ cab9ets1 except on swit*bo>ds4 ,mu/ be s plac$ t no set ( small motors1 small heat+ devices1 or inc&esc5t lamps1 :e!r gr\p$ on "o fixture or on sev]al fixtures or p5dants 7nor m ?an #af sockets or receptacles7 requir+ m ?an #ffj watts1 w be dep5d5t ^u "o cut-out4 ,by special p]mission1 9 cases :]e wir+ equal 9 size & insulation to ,no4 #ad ,b4 ,s4 gauge approv$ rubb]-cov]$ wire is c>ri$ direct into keyless sockets or receptacles1 & :]e ! location ( sockets & receptacles is su* z to r5d] unlikely ! atta*m5t ( flexible cords !reto1 ! circuits may be s arrang$ t n m ?an #a1cbj watts 7or ?irty-two sockets or receptacles7 w be dep5d5t ^u ! f9al cut-out4 ,except = signs & outl9e light+1 sockets & receptacles w be consid]$ z requir+ n less ?an #dj watts ea*4 ,all bran*es or taps f any ?ree-wire sy/em :i* are directly connect$ to lamp sockets or o!r translat+ devices1 mu/ be run z two-wire circuits if ! fuses are omitt$ 9 ! neutral or if ! diff]5ce ( pot5tial betwe5 ! two outside wires is ov] #bej volts1 & bo? wires ( su* bran* or tap circuits mu/ be protect$ by prop] fuses4 ,! above %all also apply to motors1 except t small motors may be gr\p$ "u ! protection ( a s+le set ( fuses1 provid$ ! rat$ capacity ( ! fuses does n exce$ #aj amp]es4 ,:5 #a1cbj watts are dep5d5t ^u "o fusible cut-out1 z is all[$ 9 !at] wir+1 outl9e light+1 & l>ge *&eli]s1 ! fuses may be 9 accordance ) ! foll[+3 #abe volts or less #bj amp]es #abe to #bej volts #aj amp]es ,! rat$ capacity ( fuses mu/ n exce$ ! all[able c>ry+ capacity ( ! wire4 ,circuit break]s mu/ n be set m ?an #cj p] c5t above all[able c>ry+ capacity ( ! wire1 unless a fusible cut-out is also in/all$ on ! circuit4 ,fixture wire or flexible cord ( ,no4 #ah ,b4 ,s4 gauge1 w be consid]$ z prop]ly protect$ by #aj-;amp]e fuses4 ,ea* wire ( motor circuits1 except on ma9 swit*bo>d or :5 o!rwise subject to compet5t sup]vision1 mu/ be protect$ by an approv$ fuse :e!r automatic ov]load circuit break]s are in/all$ or n4 ,s+le-phase motors may h "o side protect$ by an approv$ automatic ov]load circuit break] only if ! o!r side is protect$ by an approv$ fuse4 ,= circuits hav+ a maximum capacity great] ?an t = :i* enclos$ fuses are approv$1 circuit break]s alone w be approv$4 ,! ord9>y porcela9 l9k fuse cut-out w n be approv$4 ,l9k fuses may be us$ only :5 m\nt$ on slate or m>ble bases con=m+ to ! rules1 & mu/ be enclos$ 9 du/-tight1 fire-pro($ cab9ets1 except on swit*bo>ds locat$ well away f combu/ible mat]ial1 z 9 ! ord9>y eng9e & dynamo room1 & :]e ^! conditions w be ma9ta9$4 ,damp ,places4--,x is be/ to avoid wir+ 9 damp places if possible4 ,if wires mu/ be run 9 su* places1 !y %\ld be lead cov]$4 ,if armor$ cable is us$1 ! wires 9 cable mu/ be incas$ 9 lead4 ,wea!rpro( sockets mu/ be us$ & ! use ( cords %\ld be avoid$4 ,:]e cords mu/ be us$ !y %\ld be ( ! brew]y or pack+-h\se type4 ,if outside ( ! !at]1 prop] op5 "w may be us$4 ,conduit "w is p]missible b n advisable1 except :]e wires are subject to me*anical injury4 ,decorative ,light+ ,sy/ems4--,! comm]cial decorative light+ sy/ems are n suitable = use inside ( !at]s & %\ld be us$ only outside4 ,national ,electrical ,code ,rule = ,decorative ,light+ ,sy/ems4 ,special p]mission may be giv5 9 writ+ = ! tempor>y in/allation ( approv$ sy/ems ( decorative light+1 provid$ ! diff]5ce ( pot5tial betwe5 ! wires ( any circuit %all n be ov] #aej volts & also provid$ t no gr\p ( lamps requir+ m ?an #a1cbj watts %all be dep5d5t on "o cut-out4 ,illu/ration3 ,,figure #aeg4 ,dimm]s4--8,dimm]0 is ! "n giv5 to ! resi/ances :i* are us$ to dim ! electric lights on ! /age4 ,!y are usually m\nt$ at ! top or bottom ( ! swit*bo>d ) ! op]at+ h&les 9 easy rea* ( ! op]ator4 ,a dimm] %\ld be provid$ = ea* color 9 e bord] light & also = ! foot lights4 ,9 "s cases ! prosc5ium side lights are also arrang$ = sev]al colors4 ,! dimm]s %\ld be m\nt$ s t ea* "o is directly above ! swit* :i* controls ! circuit to :i* x belongs4 ,!y %\ld be protect$ by wire gu>ds aga9/ rubbi%1 :i* is likely to accumulate among !m if !y are n enclos$4 ,good v5tilation mu/ be provid$4 ,a c]ta9 dimm] c be us$ only :ile ! amp]age rema9s )9 ! prop] limitations4 ,if c>bon lamps1 = in/ance1 are *ang$ = tung/51 ! amp]age w be mu* r$uc$ & ! dimm] may n "w prop]ly4 ,mod]n dimm]s are all ( ! int]lock+ type s t ! :ole bank may be work$ toge!r or any "o s+ly4 ,figure #aeg is an illu/ration ( a small bank ( dimm]s4 ,door ,swit*es4--,door swit*es are us$ mo/ly 9 connection ) dress+ rooms4 ,:5 ! light 9 ! room is burn+1 op5+ & clos+ ! door w turn x out4 ,dress+ ,rooms4--,_m dress+ rooms are wir$ ) lights on p5dant cords1 b ?is me?od is n to be recomm5d$4 ,x is bett] to arrange ! lights 9 sockets fitt$ into ! outlet boxes4 ,x w be well if ea* dress+ room is provid$ ) a circuit = flatirons4 ,if ?is is consid]$ too exp5sive1 ! fuses on circuits lead+ into dress+ rooms mu/ be kept small en\gh to bl[ 9 case a flatiron is connect$4 ,_m actors are 9 ! habit ( c>ry+ flatirons & w use !m on inc&esc5t-light circuits if no o!r circuit is provid$4 ,if metal gu>ds are fa/5$ on securely1 mu* ( ! tr\ble f flatirons w be avoid$1 b !y mu/ be fa/5$ s t an ord9>y screwdriv] w n loos5 ! screws4 ,dress+ room illum9ation1 if prop]ly c>ri$ out1 w save ! proprietor mu* annoyance4 ,actors h ways ( obta9+ ! light !y want by fair means or f\l1 & x is mu* bett] to arrange ! light+ s t x w be satisfactory to ^? us+ x1 ?an to h x cont9ually tamp]$ )4 ,a bright illum9ation is ess5tial = mak+ up & bo? sides ( ! face %\ld be fully illum9at$4 ,to accompli% ?is x is necess>y to provide at lea/ two lights = ea* mirror4 ,e lamp %\ld be provid$ ) a sub/antial gu>d :i* may be securely fa/5$ to ! outlet box4 ,?is is especially necess>y if small c&le p[] lamps are furni%$4 ,=1 if ! light furni%$ is insuffici5t1 !re w be /rong ef=ts made to replace ! small lamps by l>g] ones4 ,gu>ds are also necess>y z a protection aga9/ fire4 ,actors are 9 ! habit ( dry+ small articles ( clo?+ on ! lamps1 & fires h be5 kn[n to />t f ?is cause4 ,! gu>ds on ! lamps ?r[ %ad[s on ! faces ( ! actors1 & = ?is reason are n lik$4 ,9 ord] to avoid ! %ad[s1 fro/$ lamps may be us$1 or two lamps on ea* side ( ! mirror4 ,"o lamp w !n illum9ate ! %ad[s caus$ by ! o!r4 ,:]e !re are long dress+ tables1 z 9 rooms occupi$ by ! *orus1 mirrors may be plac$ betwe5 ea* two lamps on ea* side ( ! table & ! lamps /agg]$ v]tically4 ,9 ?is way ea* p>ty w receive ! b5efit ( at lea/ f\r lamps & ! %ad[s w be less noticeable4 ,! color value ( ! lamps us$ 9 dress+ rooms %\ld mat* t ( ! lamps us$ on ! /age4 ,"s /ages1 = in/ance1 are illum9at$ by flam+ arcs :i* may give an altoge!r diff]5t effect to a 8make up0 ?an ! tung/5 lamps1 = in/ance4 ,:]e !re are a l>ge numb] ( sockets )\t lamps 9 !m1 x is advisable to close ! socket by a fuse plug f :i* ! fuse has be5 remov$1 or 9 "s simil> mann] 9 ord] to avoid ! *ance ( %ort circuits f hat p9s or simil> objects us$ 9 dress+ rooms4 ,drop ,lights4--,drop lights %\ld be avoid$ z mu* z possible4 ,:]e !y mu/ be in/all$ re9=c$ cord1 armor$ cable1 or flexible /eel armor$ cord %\ld be us$4 ,em]g5cy ,light+4--,e !at] mu/ h an em]g5cy light+ sy/em z outl9$ 9 ! rules bel[4 ,! object ( ?is is to provide a d\ble sy/em ( illum9ation s z to r$uce ! likelihood ( ! !at] be+ left 9 total d>kness4 ,?is is a frequ5t occurr5ce :]e ! !at] is suppli$ by an isolat$ plant1 & may also occur :]e ! supply is obta9$ f a l>ge outside light+ sy/em al?\gh ! latt] is usually m reliable4 ,e unnecess>y light t is add$ to an em]g5cy sy/em increases ! likelihood ( tr\ble4 ,a suffici5t numb] ( lights add$ to x to illum9ate ! space us$ by ! audi5ce 9 gett+ out is1 !re=e1 necess>y b m ?an ?is is a detrim5t r ?an a help4 ,! practice ( connect+ all ( ! hall & lobby lights to ! em]g5cy sy/em is to be condemn$1 s9ce x defeats ! purpose ( ! rule :i* provides a d\ble illum9ation sy/em = e "p ( ! !at] us$ by ! audi5ce4 ,! two sy/ems %\ld be c>ri$ into ! auditorium1 all /airways1 exits1 & lobby cle> to ! /reet4 ,!y %\ld1 fur!rmore1 be kept entirely sep>ate1 9 sep>ate conduits & us+ sep>ate met]s4 ,! rule does n specify ! numb] ( exit & em]g5cy lights requir$4 ,good practice requires a light = e #djj squ>e feet or s4 ,if ea* ( ^! outlets be fitt$ ) a #ej watt lamp ! illum9ation w int]f]e ) _m ( ! acts & s1 small] lamps are g5]ally us$4 ,"o em]g5cy light = ea* #fj seats w fill ! bill nicely4 ,illu/ration3 ,,figure #aeh4 ,ov] ea* exit1 an exit light mu/ be provid$1 b z ^! exit lights are usually incas$ 9 ruby glass su* z %[n 9 ,figure #aeh !y _c be c\nt$ z giv+ any illum9ation4 ,9 _m !at]s gas is us$ = em]g5cy & exit light+ & 9 _m respects ?is seems to be a good practice4 ,9 "s qu>t]s1 h[ev]1 x is believ$ t a fire 9 ! sc5]y ( a !at] might create su* an air pressure 9 ! build+ z to ov]come ! l[ gas pressure & ?us put out ! gas at ! v "t :5 x is mo/ ne$$4 ,! v be/ sugge/ion t c be made is t ( a /orage batt]y to supply ! em]g5cy sy/em4 ,:]e alt]nat+ curr5t is us$ ?is1 h[ev]1 introduces "s complications & becomes q exp5sive4 ,avoid ! use ( key sockets1 fan motors1 or any unnecess>y device on em]g5cy or exit light circuits4 ,national ,electrical ,code ,rules = ,s]vices4 ,:]e supply may be obta9$ f two sep>ate /reet ma9s1 two sep>ate & di/9ct s]vices mu/ be in/all$1 "o s]vice to be ( suffici5t capacity to supply curr5t = ! entire equipm5t ( !at]1 :ile ! o!r s]vice mu/ be at lea/ ( suffici5t capacity to supply curr5t = all em]g5cy lights4 ,:]e supply _c be obta9$ f two sep>ate s\rces1 ! fe$ = em]g5cy lights mu/ be tak5 f a po9t on ! /reet side ( ma9 s]vice fuses4 ,by 8em]g5cy lights0 are meant exit lights & all lights 9 lobbies1 /airways1 corridors1 & o!r portions ( !at] to :i* ! public h access1 :i* are normally kept light$ dur+ ! p]=mance4 ,:]e ! s\rce ( supply is an isolat$ plant )9 ! same build+1 an auxili>y s]vice ( at lea/ suffici5t capacity to supply all em]g5cy lights mu/ be in/all$ f "s outside s\rce1 or a suitable /orage batt]y )9 ! premises may be consid]$ ! equival5t ( su* s]vice4 ,illu/ration3 ,,figure #aei4 ,exit lights mu/ n h m ?an "o set ( fuses betwe5 same & s]vice fuses4 ,exit lights & all lights 9 halls1 corridors1 or any o!r "p ( ! build+ us$ by audi5ce1 except ! g5]al auditorium light+1 mu/ be f$ indep5d5tly ( ! /age light+1 & mu/ be controll$ only f ! lobby or o!r conv5i5t place 9 front ( ! h\se4 ,all fuses mu/ be enclos$ 9 approv$ cab9ets4 ,figure #aei %[s a diagram ( an em]g5cy light+ sy/em toge!r ) t ( ! h\se light+ sy/em4 ,! ma9 h\se swit* is sometimes arrang$ ) two sets ( fuses1 s t x ne$ only be ?r[n ov] :5 a fuse bl[s4 ,see ,figure #aei at ! "r4 ,exit ,lights4--,exit lights are usually requir$ ov] all doors lead+ f any "p ( ! auditorium to ! lobby or outside ( ! !at]4 ,!y are usually incas$ 9 ruby glass on :i* ! ^w ,,exit has be5 et*$ 9 l>ge lett]s4 ,see also ,em]g5cy ,light+4 ,fan ,motors4--,9 l>ge !at]s1 sometimes z _m z t5 or twelve fan motors are arrang$ along ! walls ( ! auditorium1 to bl[ air t[>d ! audi5ce4 ,9 small !at]s !re is a /rong temptation to connect ^! to ! em]g5cy circuit1 b ?is %\ld nev] be done4 ,! motors are too noisy to be all[$ to run dur+ an act & mu/ be wir$ s t !y c all be ?r[n on or (f toge!r f ! /age swit*bo>d4 ,n m ?an #ffj watts %\ld be connect$ to any "o circuit & ! connection %\ld be by means ( atta*m5t plugs & re9=c$ cord1 a bracket = ! motor be+ plac$ z ne> z possible to ! outlet1 s z to r$uce ! am\nt ( cord requir$ to a m9imum4 ,fire ,al>m4--,9 "s ( ! cities a special signal sy/em betwe5 /age & box (fice is requir$ & x is necess>y to consult au?orities ab\t ?is4 ,ord9>ily a bell circuit1 su* z %[n "u 8,bells10 w answ]4 ,fi% ,"w4--,! fi%+ ( wires incas$ 9 loom1 z is p]mitt$ 9 o!r places1 is n p]missible 9 !at]s4 ,if wires are to be 8fi%$0 !y mu/ be incas$ 9 metal armor4 ,fixtures4--,fixtures require c>eful inspection be=e in/all+4 ,x is seldom t ! pip+ is prop]ly ream$ out z requir$ by ! rule4 ,*a9 fixtures especially1 mu/ be closely wat*$4 ,!re is little if any tr\ble to be expect$ f ! wires lac$ among ! *a9 l9ks1 b !re is mu* tr\ble to be look$ = f ! wires at ! po9ts :]e !y leave ! *a9 support & :]e !y ent] ! socket4 ,! op5+s = ! wires at ^! po9ts are seldom l>ge en\gh to admit ( ! prop] wire be+ us$1 & !y are n well ream$ ei!r4 ,! result ( ^! conditions is t ! wire is v quickly abrad$ & %ort circuits are common4 ,fixtures may be te/$ = %ort circuit by connect+ a magneto at ! fe$ end ( ! wires & turn+ x briskly4 ,if a r+ is obta9$ x is an indication t some?+ 9 wrong4 ,! te/ = op5 circuit may be made ) ! same connection4 ,ins]t a screw driv] or a plug into ea* socket2 if x is n possible to obta9 a r+ !re mu/ be an op5 circuit4 ,! te/ = 8gr\nd0 may be made by connect+ bo? fe$ wires to "o pole ( ! magneto1 & ! o!r pole to ! metal ( ! fixture tak+ c>e t !re is no lacqu] on t "p ( ! fixture4 ,if a r+ is obta9$ x is an indication t "s b>e spot on ! wire is 9 contact ) ! fixture4 ,fixtures us$ = em]g5cy light+ mu/ c>ry no key sockets & mu/ n fe$ fan motors4 ,national ,electrical ,code ,rules = ,fixture ,wire & ,fixtures4 ,wires = ,fixture ,"w4 ,mu/ n be small] ?an ,no4 #ah ,b4 ,s4 gauge1 & mu/ h an approv$ rubb] insulat+ cov]+4 ,9 wir+ c]ta9 designs ( %[-case fixtures1 ceil+ bull-eyes1 & simil> appliances 9 :i* ! wir+ is expos$ to temp]ature 9 excess ( #abj degrees ,fahr5heit 7#di degrees c5tigrade71 f ! heat ( ! lamps1 approv$ sl[-burn+ wire mu/ be us$4 ,all su* =ms ( fixtures mu/ be submitt$ = exam9ation1 te/ & approval be=e be+ introduc$ = use4 ,supply conductors1 & especially ! splices to fixture wires1 mu/ be kept cle> ( ! gr\nd$ "p ( gas pipes1 &1 :]e %ells or outlet boxes are us$1 !y mu/ be made suffici5tly l>ge to all[ ! fulfillm5t ( ?is requirem5t4 ,mu/1 :5 fixtures are wir$ outside1 be s secur$ z n to be cut or abrad$ by ! pressure ( ! fa/5+s or motion ( ! fixture4 ,wires ( diff]5t sy/ems mu/ nev] be conta9$ 9 or atta*$ to ! same fixture1 & "u no circum/ances mu/ !re be a diff]5ce ( pot5tial ( m ?an #cjj volts betwe5 wires conta9$ 9 or atta*$ to ! same fixtures4 ,on *a9s ( simil> p>ts :]e conductors are n completely enclos$ 9 metal1 wires mu/ be /r&$ & mu/ h rubb] insulation n less ?an "o ?irty-second ( an in* 9 ?ickness2 or approv$ p5dant or portable cord may be us$4 ,fixtures4 ,:5 support$ at outlets 9 metal conduit1 armor$ cable1 or metal-mold+ sy/ems1 or f gas pip+ or any gr\nd$ metal "w1 or :5 in/all$ on metal walls or ceil+s1 or on pla/] walls or ceil+s conta9+ metal la?1 or on walls or ceil+s 9 firepro( build+s1 fixtures mu/ be insulat$ f su* supports by approv$ insulat+ jo9ts plac$ z close z possible to ! ceil+s or walls4 ,! insulat+ jo9t may be omitt$ 9 conduit1 armor$ cable1 or metal-mold+ sy/ems ) /raight electric fixtures 9 :i* ! insulation ( conductors is ! equival5t ( insulation 9 o!r p>ts ( ! sy/em1 & provid$ t approv$ sockets1 receptacles1 or wireless clu/]s are us$ ( a type hav+ porcela9 or equival5t insulation betwe5 live metal p>ts & out] metal %ells1 if any4 ,:]e insulat+ jo9ts are requir$1 fixture canopies ( metal mu/ be ?or\ghly & p]man5tly insulat$ f metal walls or ceil+s1 or f pla/] walls or ceil+s on metal la?+1 & f outlet boxes4 ,canopy insulators mu/ be securely fa/5$ 9 place s z to sep>ate ! canopies ?or\ghly & p]man5tly f ! surfaces & outlet boxes f :i* !y are design$ to be insulat$4 ,fixtures hav+ s-call$ flat canopies1 tops1 or backs1 w n be approv$ = in/allation1 except :]e outlet boxes are us$4 ,9 non-metallic fixtures wireways mu/ be metal-l9$ unless approv$ armor$ conductors ) suitable fitt+s are us$4 ,fla%]s4--,fla%]s are us$ to economize electrical en]gy 9 sign illum9ation4 ,an electric sign is (t5 j z effective if only "o side or "o lett] is 9 use at a "t & 9 su* a case !re is consid]able sav+ by ! use ( a fla%]4 ,illu/ration3 ,,figure #afj4 ,fla%]s are made up 9 a v>iety ( =ms1 "o ( !m be+ %[n 9 ,figure #afj4 ,! mann] ( wir+ to ! sign w be readily und]/ood by ref]5ce to ! figure4 ,! neutral wire is c>ri$ direct to ! sign & fuses = t wire are (t5 in/all$ up 9 ! sign1 :ile ^? = ! o!r side ( ! circuits mu/ be close to ! fla%] to comply ) ! rule :i* requires fuse protection :]e a small wire is tapp$ (f f a l>g] "o1 unless ! fuse 9 ! l>g] wire is bel[ ! c>ry+ capacity ( ! small]4 ,national ,electrical ,code ,rule = ,fla%]s4 ,"t swit*es1 sign fla%]s1 & simil> appliances mu/ be ( approv$ design & enclos$ 9 approv$ cab9ets4 ,flat ,irons4--,see ,heat]s4 ,flexible ,cord4--,! ord9>y flexible cord %\ld n be us$ 9 any "p ( a !at]4 ,x is recomm5d$ t only ^? cords describ$ bel[ be us$1 ea* ( c\rse 9 its prop] place4 ,approv$ re9=c$ cord = p5dants4 ,approv$ asbe/os-cov]$ cord = portable heat]s4 ,approv$ ,/age & ,bord] ,cables on ,/age4 ,see 8,/age ,cables40 ,flexible ,tub+4--,flexible tub+ is n p]missible 9 !at]s4 ,floor ,pockets4--,^! are always a s\rce ( tr\ble & _! use %\ld be avoid$ z mu* z possible4 ,if x is necess>y to use any !y mu/ be ( a type approv$ by ! inspection dep>tm5t hav+ jurisdiction4 ,fly ,floor4--,?is is ! "n giv5 to t "p ( ! gall]y above ! /age ^u :i* ^? employes1 ^: duty x is to raise & l[] curta9s & sc5]y1 "w4 ,no great illum9ation is requir$1 b ! lights %\ld be arrang$ s z to be conv5i5t to ! m5 = read+ dur+ long waits4 ,if ?is is n done !re w always be consid]able objectionable cord wir+ f\nd 9 ?is place4 ,fly-floor & rigg+-l(t lights %\ld be provid$ ) ?ree way swit*es s t lights may be turn$ on or (f ei!r at ! /age swit*bo>d or on ! fly floor4 ,footlights4--,^! =m ! mo/ important & effective "p ( ! p]man5tly locat$ /age lights4 ,to locate !m prop]ly requires c>eful consid]ation4 ,if !y are br\ght too high !y w ob/ruct ! view ( ! audi5ce2 if locat$ too l[ !y w n illum9ate ! l[] "p ( ! /age4 ,op9ion is some:at divid$ z to :e!r !y ought to be arrang$ 9 circul> =m or be laid out /raight across ! /age4 ,9 l>ge !at]s !re is a circul> space betwe5 ! front seats & ! front ( ! /age4 ,a circul> /age w utilize ?is space & ?is =m ( /age ) footlights arrang$ 9 a simil> mann] w also all[ ! actors to approa* m closely to ! audi5ce & w procure = !m "s illum9ation f ! side4 ,! difficulty ( mak+ up a circul> /rip ( footlights is some:at great] ?an t ( mak+ !m up 9 a /raight l9e4 ,illu/ration3 ,,figure #afa4 ,illu/ration3 ,,figure #afb4 ,! footlights are g5]ally made to ext5d ne>ly ! full op5+ ( ! /age & ! lights %\ld be cr[d$ into !m z closely z possible4 ,! light+ %\ld be divid$ into ?ree gr\ps suitable = ?ree colors4 ,x is cu/om>y to h ab\t half ( ! lights :ite & ! rema9+ half divid$ into two equal p>ts = diff]5t colors4 ,a small "p ( ! :ite lights %\ld be arrang$ ^u a sep>ate circuit s t !y may be us$ = rehe>sals or o!r purposes1 :5 n v mu* light is ne$$4 ,no v def9ite recomm5dations conc]n+ ! type ( lamp to be us$ c be giv54 ,9 "s !at]s ! /age is v solid & tung/5 lamps are us$ to advantage2 9 o!rs ! j>r+ prev5ts _! use4 ,! :ite lights %\ld be arrang$ s t _! light ne$ n pass ?r\gh ! color$ lamps4 ,9 vaudeville h\ses "s protection 9 ! =m ( *a9s or gu>ds is (t5 provid$ to prev5t objects f be+ roll$ or ?r[n aga9/ ! lights4 ,figures #afa & #afb %[ types ( footlights & ! mann] ( in/all+ ! sockets4 ,! ,national ,electrical ,code ,rules = ,wir+ ,footlights4 ,mu/ be wir$ 9 approv$ conduit or armor$ cable1 ea* lamp receptacle be+ enclos$ )9 an approv$ outlet box1 or ! lamp receptacles may be m\nt$ 9 an iron or /eel box1 metal to be ( a ?ickness n less ?an ,no4 #bj ,u4 ,s4 %eet metal gauge treat$ to prev5t oxidation & s con/ruct$ z to enclose all ! wires4 ,wires to be sold]$ to lugs ( receptacles4 ,mu/ be s wir$ t no set ( lamps requir+ m ?an #a1cbj watts nor m ?an #bf receptacles %all be dep5d5t ^u "o cut-out4 ,fuses4--,see 8,cut-outs40 ,gall]y ,light+4--,! prop] light+ ( gall]ies is a difficult matt] :]e !re is ano!r gall]y above4 ,9 su* a case ! ceil+ is always v l[4 ,an ev5 di/ribution ( light requires ! use ( _m small inc&esc5t lamps ev5ly di/ribut$4 ,?is w make ! wir+ exp5sive4 ,! light %\ld be tak5 pretty well f ! re> s z to avoid plac+ lights 9 ! range ( visions ( ! audi5ce4 ,em]g5cy lights %\ld be provid$ "h z well z 9 ! ma9 auditorium4 ,gall]y ,pockets4--,pockets = arc lamps are (t5 provid$1 z x (t5 happ5s t a mov+-picture ma*9e mu/ be plac$ 9 ! gall]y4 ,! /age pockets %\ld be wir$ ) numb] #f ,b4 ,s4 gauge wire1 ?is be+ ! smalle/ wire all[$ to fe$ a mov+-picture arc4 ,! /age pocket %\ld be controll$ by a swit* on ! swit*bo>d4 ,x (t5 happ5s t ! op]ator at ! lamp has a wrong cue & 8 light c !n be controll$ by ! /age manag] at ! /age swit*bo>d4 ,gas ,light+4--,electric gas light+ is v little us$ at ! pres5t "t1 b 9 _m !at]s ! em]g5cy light+ is by gas &1 9 ord] to save ! "t necess>y to light ^! by h& be=e e p]=mance1 an automatic gas light+ sy/em has be5 in/all$ 9 "s !at]s4 ,a diagram ( su* a sy/em is %[n 9 ,figure #afc4 ,a batt]y ( consid]able capacity is necess>y & also a sp>k coil ,s4 ,at ea* gas jet a magnet ,m is in/all$ :i*1 :5 en]giz$1 is capable ( turn+ ! gas on & at ! same "t produc+ a sp>k4 ,?is magnet is also capable ( turn+ ! gas (f4 ,two buttons are provid$1 "o to turn ! gas on & ! o!r to turn x (f4 ,illu/ration3 ,,figure #afc4 ,z ! wir+ is always us$ 9 connection ) gas pip+1 gr\nds are ( frequ5t occurr5ce1 & 9 ord] to indicate a gr\nd z soon z x comes on1 ! bell & batt]y %[n are provid$4 ,if a gr\nd causes a cont9u\s curr5t1 ! sp>k coil w attract ! armature1 ?us caus+ ! bell to r+ cont9u\sly4 ,national ,electrical ,code ,rule = ,gas ,light+4 ,electric gas light+1 unless x is ! frictional sy/em1 mu/ n be us$ on ! same fixtures ) ! electric light4 ,grid ,floor4--,?is is ! t]m giv5 to ! framework :i* supports ! pulleys ov] :i* ! cables = h&l+ curta9s & sc5]y run4 ,x is usually made up ( p>allel iron slats or b>s2 h5ce ! "n4 ,a fairly good illum9ation %\ld be provid$ "h & all ( ! lights %\ld be arrang$ on ?ree-way swit*es4 ,"o light = e #djj squ>e feet w be suffici5t4 ,national ,electrical ,code ,rule = ,gr\nd ,clamps4 ,connections to gr\nd$ pipes & to conduit mu/ be expos$ to view or be readily accessible1 & mu/ be made by means ( approv$ gr\nd clamps to :i* ! gr\nd wire mu/ be sold]$4 ,national ,electrical ,code ,rule = ,gr\nd+4 ,! metal ( conduit1 armor$ cable1 or metal mold+ mu/ be p]man5tly & effectually gr\nd$ to wat] pip+1 gas pip+1 or o!r suitable gr\nds1 provid$ t1 :5 connections are made to gas pip+1 !y mu/ be on ! /reet side ( ! met]4 ,if ! conduit sy/em consi/s ( sev]al sep>ate sections1 ! sections mu/ be bond$ to ea* o!r1 & ! sy/em gr\nd$2 or ea* section may be sep>ately gr\nd$1 z requir$ above4 ,conduits & gas pipes mu/ be securely fa/5$ 9 outlet boxes1 junction boxes1 & cab9ets1 s z to secure good electrical connections4 ,if conduit1 c\pl+s1 outlet boxes1 junction boxes1 cab9ets1 or fitt+s1 hav+ protective coat+ ( non-conduct+ mat]ial su* z enamel1 are us$1 su* coat+ mu/ be ?or\ghly remov$ f ?reads ( bo? c\pl+s & conduit & su* surfaces ( boxes1 cab9ets & fitt+s :]e ! conduit or gr\nd clamp is secur$ 9 ord] to obta9 ! requisite good connection4 ,gr\nd$ pipes mu/ be clean$ ( ru/1 scale1 etc41 at place ( atta*m5t ( gr\nd clamp4 ,connections to gr\nd$ pipes & to conduit mu/ be expos$ to view or readily accessible1 & mu/ be made by means ( approv$ gr\nd clamps to :i* ! gr\nd wires mu/ be sold]$4 ,gr\nd wires mu/ be ( copp]1 at lea/ ,no4 #aj ,b4 ,s4 gauge 7:]e l>ge/ wire conta9$ 9 conduit is n great] ?an ,no4 #j ,b4 ,s4 gauge71 & ne$ n be great] ?an ,no4 #d ,b4 ,s4 gauge 7:]e l>ge/ wire conta9$ 9 conduit is great] ?an ,no4 #j ,b4 ,s4 gauge74 ,!y %all be protect$ f me*anical injury4 ,! gr\nd on ! conduit sy/em is n to be consid]$ z a gr\nd = a second>y sy/em4 ,gu>ds4--,a gu>d rail %\ld be provid$ ar\nd ! /age swit*bo>d to prev5t actors f com+ 9 contact ) any live "p ( ! swit*bo>d4 ,all inc&esc5t lamps ab\t ! /age1 dress+ rooms1 fly-floor1 grid-floor1 etc41 %\ld be provid$ ) gu>ds4 ,hang]-,bo>ds4--,hang]-bo>ds are n compulsory b :]e n us$1 arc lamps mu/ be hung f insulat+ supports o!r ?an _! conductors4 ,national ,electrical ,code ,rule = ,hang]-,bo>ds = ,s]ies ,arc ,lamps4 ,hang]-bo>ds mu/ be s con/ruct$ t all wires & curr5t-c>ry+ devices !reon w be expos$ to view & ?or\ghly insulat$ by be+ m\nt$ on a non-combu/ible1 non-absorptive1 insulat+ sub/ance4 ,all swit*es atta*$ to ! same mu/ be s con/ruct$ t !y %all be automatic 9 _! action1 cutt+ (f bo? poles to ! lamps1 n /opp+ betwe5 po9ts :5 />t$1 & prev5t+ an arc betwe5 po9ts "u all circum/ances4 ,heat]s4--,heat]s are us$ sometimes 9 cold dress+ rooms1 9 box (fices & 9 o!r small spaces :]e o!r adequate heat+ arrangem5ts h n be5 made4 ,! fire haz>d incid5t to ! use ( electric heat]s is consid]able & !y %\ld be c>efully in/all$ accord+ to ! rules giv5 bel[4 ,f "o-half to ?ree watts p] cubic foot w be requir$ to heat a room4 ,! quantity ( heat necess>y to be suppli$ dep5ds l>gely ^u ! v5tilation4 ,x w be small 9 clos$ dress+ rooms & l>ge1 = in/ance1 9 ! box (fice4 ,always place a heat] :]e ! air ent]s a room2 nev] :]e x leaves4 ,national ,electrical ,code ,rules = ,electric ,heat]s4 ,ea* heat] ( m ?an #f amp]es or #ffj watts capacity mu/ be protect$ by a cut-out1 & controll$ by a swit* or plug connector pla9ly indicat+ :e!r 8on0 or 8(f0 & locat$ )9 sight ( ! heat]4 ,heat]s ( #f amp]es or #ffj watts capacity1 or less1 may be gr\p$ "u ! protection ( a s+le set ( fuses1 provid$ ! rat$ capacity ( ! fuses does n exce$ #aj amp]es2 or may be connect$ individually to light+ circuits4 ,flexible conductors = smoo?+ irons & sad irons1 & = all devices requir+ ov] #bej watts1 mu/ h an approv$ insulation & cov]+4 ,) portable heat+ devices1 approv$ plug connectors mu/ be us$ s arrang$ t ! plug may be pull$ out to op5 ! circuit )\t leav+ any live p>ts s expos$ z to r5d] likely accid5tal contact !re)4 ,! connector may be locat$ at ei!r end ( ! flexible conductor or ins]t$ 9 ! conductor itself4 ,smoo?+ irons1 sad irons1 & o!r heat+ devices t are int5d$ to be appli$ to combu/ible articles1 mu/ be provid$ ) approv$ /&s4 ,/ation>y heat]s su* z radiators1 ranges1 plate w>m]s1 etc41 mu/ be s locat$ z to furni% ample protection betwe5 ! device & surr\nd+ combu/ible mat]ial4 ,mu/ ea* be provid$ ) a "n-plate1 giv+ ! mak]'s "n & ! normal capacity 9 volts & amp]es4 ,high ,pot5tial4--,! ,national ,electrical ,code classifies all voltages bel[ #eej z l[4 ,nev]!less voltages above #bbj %\ld n be consid]$ 9 ! auditorium1 /age1 or dress+ rooms ( any !at]4 ,& ?is voltage only 9 connection ) a ?ree-wire sy/em :]e ! high voltage exi/s only betwe5 ! outside wires1 & #aaj volts are us$ = lamps & o!r devices4 ,high pot5tial sy/ems %\ld be us$ only on ! outside4 ,illum9ation4--,illum9ation is m an art ?an a sci5ce & ! rules t c be giv5 h only a v g5]al application4 ,! be/ practice1 :]e really good illum9ation is desir$1 is to in/all a l>ge numb] ( circuits 9 proportion to ! numb] ( lights1 s t lamps ( l>ge c&le p[] may be us$ :]ev] desirable4 ,! quantity ( light ne$$ 9 !at]s v>ies greatly ) ! color ( decorations & ) _! condition4 ,du/ accumulates rapidly 9 !at]s & may absorb half ( ! light4 ,if !re is pl5ty ( capacity ! c&le p[] ( lamps may be *ang$ to suit conditions & obta9 any result desir$4 ,! numb] ( sockets in/all$ 9 ! auditorium v>ies widely4 ,9 "s ( ! *eap] !at]s "o light = ea* tw5ty seats is consid]$ suffici5t2 :ile 9 elaborately light$ h\ses1 !re are cases :]e ! numb] ( sockets is equal to ab\t half ! numb] ( seats4 ,good illum9ation requires t ! light come f ! back1 b v (t5 ! purpose is to obta9 a brilliant effect by plac+ lights 9 front ( ! audi5ce4 ,9 su* cases1 h[ev]1 ! lamps are always ( l[ c&le p[] & %\ld be fro/$4 ,inc&esc5t ,lamps4--,practically all inc&esc5t lamps are n[ rat$ 9 watts4 ,!y c be obta9$ 9 voltages rang+ f #b to #bej & may be op]at$ 9 s]ies or 9 multiple4 ,all b ! tantalum lamp op]ates equally well on alt]nat+ or direct curr5t4 ,! tantalum _c be recomm5d$ = alt]nat+-curr5t circuits4 ,no inc&esc5t lamps w op]ate well on frequ5cies l[] ?an =ty cycles4 ,! natural di/ribution ( light is mo/ly 9 ! horizontal plane & = good illum9ation reflectors %\ld be provid$4 ,! color value is 9 ! foll[+ ord]3 ,tung/51 tantalum1 graphitiz$ filam5t1 c>bon filam5t4 ,none are equal = color-mat*+ purposes to ! int5sifi$ arc or ! ,moore tube4 ,! life ( all inc&esc5t lamps v>ies inv]sely ) ! voltage4 ,an increase 9 voltage w produce an increase 9 ! effici5cy ( ! lamp b %ort5 its life4 ,! effici5cy decreases ) cont9u$ use1 & x is g5]ally consid]$ t ! useful life ( a lamp is ov] :5 its effici5cy has fall5 to #hj p] c5t ( its orig9al value4 ,fro/+ or color+ %ort5s ! life ( lamps f #cj to #ej p] c5t & r$uces ! c&le p[] f #c to #aj p] c5t1 b ! lamp yields a m pleas+ light4 ,fro/+ is ord9>ily us$ only :]e lamps are plac$ s z to come 9 ! l9e ( vision4 ,b[l fro/+ does n mat]ially r$uce ! life ( a lamp4 ,effici5cy ( ,lamps4 ,) inc&esc5t lamps ! t]m 8effici5cy0 has a mean+ q diff]5t f t usually giv51 x be+ ! numb] ( watts p] c&le p[]4 ,! l[] ! effici5cy ( an inc&esc5t lamp1 ! bett] x is & ! m light x yields p] watt consum$4 ,mazda ,lamp4 ,! ,mazda lamp has an effici5cy ( ab\t #a4be & is ! mo/ effici5t ( all4 ,x may be recomm5d$ 9 all places :]e lamps may be susp5d$ v]tically2 :]e !re is n too mu* j>r+2 :]e !re is ord9>y c>e 9 h&l+2 & :]e ! lamps are burn+ a l>ge "p ( ! "t4 ,! op]at+ exp5se ( ?is lamp is l[1 b ! initial co/ is high & ! breakage is likely to be consid]able4 ,if lamps are mu* h&l$ & n burn$ mu*1 ! co/ ( brok5 lamps may exce$ ! sav+ 9 en]gy4 ,x is be/ n to clean ,mazda lamps :5 cold4 ,%ock absorb]s %\ld be us$ :]e !re is mu* j>r+4 ,! illum9ation %\ld be laid out = ! use ( lamps n small] ?an #fj watts4 ,! lamps %\ld n be us$ = tempor>y "w or = color+4 ,arrange lamps z f> z possible to be controll$ by swit*es4 ,brok5 filam5ts c (t5 be unit$ aga9 by %ak+ ! lamps g5tly until ! brok5 ends come toge!r4 ,! curr5t w !n weld !m4 ,:5 a bank ( ,mazda lamps is turn$ on !re is an excessive curr5t = an in/ant4 ,tantalum ,lamp4 ,! effici5cy ( ?is lamp is f #a4h to #b watts p] c&le p[]4 ,?is lamp is mu* us$ = /reet-c> & simil> illum9ation because x /&s j>r+ v well4 ,x %\ld n be us$ on alt]nat+-curr5t circuits4 ,! filam5t c (t5 be unit$ 9 ! same mann] z ! ,mazda4 ,graphitiz$ ,filam5t ,lamp4 ,?is lamp has an effici5cy ( #b4e watts p] c&le p[]4 ,c>bon ,filam5t ,lamp4 ,?is lamp us$ on #aaj-volt circuits has an effici5cy ( f #c to #c4b watts p] c&le p[]4 ,! effici5cy ( ! small] sizes is f #d to #e watts p] c&le p[]4 ,! c>bon filam5t lamp is ! mo/ exp5sive ( all to op]ate1 b on acc\nt ( ! /r5g? & *eapness ( ! lamp x c be recomm5d$ 9 places :]e ! breakage is liable to be great or :]e ! light is us$ = comp>atively brief p]iods4 ,national ,electrical ,code ,rules = ,inc&esc5t ,lamps4 ,mu/ be provid$ ) gu>ds :5 liable to come 9 contact ) inflammable mat]ial or subject to r\gh usage4 ,mu/ be protect$ by vapor-pro( globes :]e inflammable gases exi/4 ,national ,electrical ,code ,rules = ,insulat+ ,jo9ts4 ,:5 support$ at outlets 9 metal conduit1 armor$ cable1 or metal mold+ sy/ems1 or f gas pip+ or any gr\nd$ metal "w2 or :5 in/all$ on metal walls or ceil+s1 or on pla/] walls or ceil+s conta9+ metal la?1 or on walls or ceil+s 9 firepro( build+s1 fixtures mu/ be insulat$ f su* supports by approv$ insulat+ jo9ts plac$ z close z possible to ! ceil+s or walls4 ,! insulat+ jo9t may be omitt$ 9 conduit1 armor$ cable1 or metal mold+ sy/ems ) /raight electric fixtures 9 :i* ! insulation ( conductors is ! equival5t to insulation 9 o!r p>ts ( ! sy/em1 & provid$ t approv$ sockets1 receptacles1 or wireless clu/]s are us$ ( a type hav+ porcela9 or equival5t insulation betwe5 live metal p>ts & out] metal %ells1 if any4 ,:]e insulat+ jo9ts are requir$1 fixture canopies ( metal mu/ be ?or\ghly & p]man5tly insulat$ f metal walls or ceil+s1 or f pla/] walls or ceil+s on metal la?+1 & f outlet boxes4 ,canopy insulators mu/ be securely fa/5$ 9 place1 s z to sep>ate ! canopies ?or\ghly & p]man5tly f ! surfaces & outlet boxes f :i* !y are design$ to be insulat$4 ,inv]t$ ,light+4--,9 ?is me?od ( light+ ! light is fir/ ?r[n upw>d aga9/ ! ceil+ & !n reflect$ back4 ,?is me?od c be us$ to advantage ) light color$ ceil+s only4 ,x is especially suit$ = l[ ceil+s & ) high ceil+s ! advantage disappe>s4 ,! light obta9$ 9 ?is mann] is v ev5 & almo/ %ad[less4 ,mu* light is lo/ ?r\gh absorption b1 ow+ to ! fact t ! light is ( su* an ev5 quality1 ! eye readily accommodates itself to a l[] quantity & ! net increase 9 en]gy requir$ to illum9ate suitable spaces is n s v great4 ,^? :o wi% to g into ! subject ( illum9ation ?or\ghly w f9d x treat$ fully 9 8,mod]n ,illum9ation ,!ory & ,practice04 ,jo9ts4--,me?ods ( mak+ jo9ts are illu/rat$ 9 ,figure #afd4 ,be c>eful n to ov]heat1 especially at po9ts :]e !re is a /ra9 on ! wire4 ,national ,electrical ,code ,rule = ,jo9ts4 ,wires mu/ be s splic$ or jo9$ z to be bo? me*anically & electrically secure )\t sold]4 ,! jo9ts mu/ !n be sold]$ unless made ) "s =m ( approv$ splic+ device1 & cov]$ ) an insulation equal to t on ! conductors4 ,illu/ration3 ,,figure #afd4 ,/r&$ wires 7except 9 flexible cords7 mu/ be sold]$ be=e be+ fa/5$ "u clamps or b9d+ screws2 &1 :e!r /r&$ or solid1 :5 !y h a conductivity great] ?an t ( ,no4 #h ,b4 ,s4 gauge !y mu/ be sold]$ into lugs = all t]m9al connections1 except :]e an approv$ sold]less t]m9al connector is us$4 ,junction ,boxes4--,junction boxes are in/all$ 9 conduit sy/ems = ! purpose ( facilitat+ ! draw+ 9 ( ! wire or ( bran*+ (f f a ma9 run4 ,see 8,conduit ,"w40 ,lamps4--,see 8,inc&esc5t ,lamps40 ,lobby4--,! lobby g5]ally requires a numb] ( lights & ! aim (t5 is to create a lavi% display4 ,v (t5 a cut-out c5t] is arrang$ at "s conv5i5t place4 ,! exit & em]g5cy lights mu/ be controll$ f ! lobby4 ,sometimes outlets are provid$ = electric bullet9 bo>ds or small signs4 ,lugs4--,= sold]less lugs1 su* z are us$ on rheo/ats or = arc lamps1 see 8,portable ,/age ,equipm5t40 ,national ,electrical ,code ,rule = ,lugs4 ,= fuses rat$ ov] #cj amp]es lugs1 firmly screw$ or bolt$ to ! t]m9als & into :i* ! conduct+ wires are sold]$1 mu/ be us$4 ,on rheo/ats1 resi/ances1 etc41 lugs w n be requir$ :5 leads are provid$ z a "p ( ! device4 ,swit*es = curr5t ( ov] #cj amp]es mu/ be equipp$ ) lugs1 firmly screw$ or bolt$ to ! swit*1 & into :i* ! conduct+ wires %all be sold]$4 ,= ! small] siz$ swit*es simple clamps c be employ$1 provid$ !y are heavy en\gh to /& consid]able h>d usage4 ,:]e lugs are n provid$1 a rugg$ d\ble-,v groove clamp is advis$4 ,a set screw gives a contact at only "o po9t1 is m likely to become loos5$1 & is almo/ sure to cut into ! wire4 ,= ! small] sizes1 a screw & wa%] connection ) up-turn$ lugs on ! swit* t]m9al gives a satisfactory contact4 ,national ,electrical ,code ,rules = ,metal ,mold+s4 ,mu/ n be us$ on /age side ( prosc5ium wall4 ,mu/ n be us$ = circuits c>ry+ m ?an #a1cbj watts4 ,wire us$ mu/ be /&>d rubb] cov]$1 b may be s+le braid4 ,mu/ nev] be conceal$ or run 9 damp places4 ,mu/ n be us$ :]e ! diff]5ce ( pot5tial exce$s #cjj volts4 ,mu/ be cont9u\s f outlet to outlet1 to junction boxes1 or approv$ fitt+s design$ especially = use ) metal mold+s1 & mu/ at all outlets be provid$ ) approv$ t]m9al fitt+s :i* w protect ! insulation ( conductors f abrasion1 unless su* protection is af=d$ by ! con/ruction ( ! boxes or fitt+s4 ,su* mold+ :]e pass+ ?r\gh a floor mu/ be c>ri$ ?r\gh an iron pipe ext5d+ f ! ceil+ bel[ to a po9t five feet above ! floor1 :i* w s]ve z an additional me*anical protection & exclude ! pres5ce ( moi/ure (t5 preval5t 9 su* locations4 ,:]e ! me*anical /r5g? ( ! mold+ itself is adequate1 ?is rul+ may be modifi$ to require ! protect+ pip+ f ! ceil+ bel[ to a po9t at lea/ ?ree in*es above ! floor+4 ,:]e su* mold+s pass ?r\gh a p>tition ! iron pipe1 requir$ = pass+ ?r\gh floors1 may be omitt$ & ! mold+ pass$ directly ?r\gh1 provid+ ! p>tition is dry & ! mold+ is 9 a cont9u\s l5g? ) no jo9t or c\pl+ )9 ! p>tition4 ,back+ mu/ be secur$ 9 position by screws or bolts1 ! heads ( :i* mu/ be flu% ) ! metal4 ,mu/ h ! metal ( mold+ p]man5tly & effectually gr\nd$ to wat] pip+1 gas pip+1 or o!r suitable gr\nds1 provid$ t :5 connections are made to gas pip+1 !y mu/ be on ! /reet side ( ! met]4 ,if ! metal mold+ sy/em consi/s ( sev]al sep>ate sections1 ! sections mu/ be bond$ to ea* o!r & ! sy/em gr\nd$1 or ea* section may be sep>ately gr\nd$1 z requir$ above4 ,metal mold+s & gas pipes mu/ be securely fa/5$ to outlet boxes1 junction boxes1 & cab9ets1 s z to secure a good electrical connection4 ,mold+ mu/ be s in/all$ t adjac5t l5g?s ( mold+ w be me*anically & electrically secur$ at all po9ts4 ,if metal mold+1 c\pl+s1 outlet boxes1 junction boxes1 cab9ets1 or fitt+s hav+ protective coat+ ( non-conduct+ mat]ial su* z enamel are us$1 su* coat+ mu/ be ?or\ghly remov$ f ?reads ( c\pl+s & metal mold+s1 & f ! surfaces ( boxes1 cab9ets1 & fitt+s1 :]e ! metal mold+ or gr\nd clamp is secur$ 9 ord] to obta9 ! requisite good connection4 ,gr\nd$ pipes mu/ be clean$ ( ru/1 scale1 etc41 at ! place ( atta*m5t ( ! gr\nd clamp4 ,connection to gr\nd$ pipes & to metal mold+s mu/ be expos$ to view1 or readily accessible1 & mu/ be made by means ( approv$ gr\nd clamps1 to :i* ! wires mu/ be sold]$4 ,gr\nd wires mu/ be ( copp]1 at lea/ ,no4 #aj ,b4 ,s4 gauge4 ,!y %all be protect$ f me*anical injury4 ,illu/ration3 ,,figure #afe4 ,mu/ be in/all$ s t = alt]nat+-curr5t sy/ems ! two or m wires ( a circuit w be 9 ! same metal mold+4 ,x is sugge/$ t ?is be done = direct-curr5t sy/ems also s t !y may be *ang$ to ! alt]nat+-curr5t sy/em at any "t1 induction tr\bles prev5t+ su* *ange if ! wires are 9 sep>ate mold+s4 ,met]s4--,a good job ( met] sett+ requires t ! met] fitt+s :i* are n[ on ! m>ket be us$4 ,two sep>ate met]s w be requir$ 9 ea* !at]2 "o = ! g5]al light+ & "o = ! em]g5cy sy/em4 ,met] ,read+4--,met] read+s are indicat$ by po9t]s1 arrang$ to move ov] dials z %[n 9 ,figure #afe4 ,! v>i\s po9t]s are connect$ toge!r by ge>+ 9 su* a mann]1 t alt]nate po9t]s move 9 opposite directions1 z indicat$ by ! figures on ! dials4 ,! ge>+ mov+ ! po9t]s 9 ,figure #afe is ( su* proportions t a total revolution ( any po9t] repres5ts "o-t5? ( a revolution ( ! po9t] to ! left ( x4 ,?us t5 revolutions ( "o po9t] causes "o revolution ( ! "o at ! left4 ,illu/ration3 ,,figure #aff4 ,illu/ration3 ,,figure #afg4 ,at ! top ( ea* dial ! value ( ! read+ ( t dial is %[n4 ,:]e ! figures giv5 are foll[$ by ! lett] 8s01 z 9 ,figures #afg & #afh1 x signifies t ea* division ( ! dial repres5ts ! am\nt ( en]gy indicat$ by ! figures at ! top4 ,= in/ance1 9 ,figure #afh ea* division ( ! dial at ! "r repres5ts "o-t5? ( "o kil[att h\r & a total revolution ( ! po9t] t5-t5?s1 or "o kil[att h\r4 ,if ! figures giv5 at ! top ( ! dial are n foll[$ by ! lett] 8s01 or z %[n 9 ,figure #aff1 ea* division ( ! dial repres5ts "o-t5? ( ! am\nt %[n at ! top ( ! dial1 ! dial at ! "r ( ,figure #aff indicat+ n9e-t5?s ( t5 kil[atts or n9e kil[atts4 ,illu/ration3 ,,figure #afh4 ,! met] mu/ always be read f "r to left1 ! l[e/ indicat+ dial be+ ! "o at ! extreme "r1 & ! l[] read+ ones always be+ us$ to *eck ! high] ones j at ! left4 ,! foll[+ example w illu/rate ! mann] ( read+ met]s3 ,9 ,figure #afe ! "r-h& po9t] regi/]s n9e-t5?s ( #ajjj1 or #ijj watt h\rs2 ! po9t] next to x regi/]s eight1 s9ce x _c be consid]$ z fully up to any numb] unless ! po9t] at ! "r ( x has j arriv$ at or pass$ #j4 ,by ! same tok5 ! middle po9t] also regi/]s #h & z ! middle po9t] has n rea*$ #j ! "o at ! left ( x mu/ be read z "o1 ! la/ dial also indicates "o & ! total read+ is #a1ahh1ijj4 ,on "s types ( met]s a multipli] is us$4 ,?is is g5]ally giv5 on ! met] dial & ! read+s giv5 by ! po9t]s mu/ be multipli$ by ?is numb] to obta9 ! correct read+ ( ! met]4 ,motors4--,motors are us$ 9 !at]s = v5tilation1 = rais+ & l[]+ ! /eel curta9 9 cities :]e su* are requir$1 & also 9 "s cases = op]at+ drop curta9s1 b = ?is la/ purpose !y h n f\nd mu* favor4 ,9 "s localities motors are requir$ to keep up a c]ta9 wat] pressure to be us$ 9 case ( fire4 ,voltages high] ?an #eej are n consid]$ 9 !at] "w4 ,national ,electrical ,code ,rules = #eej-volt ,motors & ,less4 ,motors op]at+ at a pot5tial ( #eej volts or less mu/ be ?or\ghly insulat$ f ! gr\nd :]ev] feasible4 ,wood5 base frames us$ = ?is purpose1 & wood5 floors1 :i* are dep5d$ ^u = insulation :]e1 = any reason1 x is necess>y to omit ! base frames1 mu/ be kept fill$ to prev5t absorption ( moi/ure1 & mu/ be kept clean & dry4 ,:]e frame insulation is impracticable special p]mission 9 writ+ may be giv5 = its omission1 9 :i* case ! frame mu/ be p]man5tly & effectively gr\nd$4 ,! motor leads or bran* circuits mu/ be design$ to c>ry a curr5t at lea/ #be p] c5t great] ?an t = :i* ! motor is rat$4 ,:]e ! wires "u ?is rule w\ld be ov]-fus$ 9 ord] to provide = ! />t+ curr5t1 z 9 ! case ( _m ( ! alt]nat+-curr5t motors1 ! wires mu/ be ( su* size z to be prop]ly protect$ by ^! l>g] fuses4 ,ea* motor & resi/ance box mu/ be protect$ by a cut-out & controll$ by a swit*2 said swit* pla9ly indicat+ :e!r 8on0 or 8(f04 ,small motors may be gr\p$ "u ! protection ( a s+le set ( fuses1 provid$ ! rat$ capacity ( ! fuses does n exce$ #f amp]es4 ,) motors ( "o-f\r? horse p[] or less1 on circuits :]e ! voltage does n exce$ #cjj1 s+le-pole swit*es may be us$4 ,! swit* & rheo/at mu/ be locat$ )9 sight ( ! motor1 except 9 cases :]e special p]mission to locate !m else:]e is giv51 9 writ+4 ,:]e ! circuit-break+ device on ! motor-/>t+ rheo/at disconnects all wires ( ! circuit1 ! swit* call$ = 9 ?is section may be omitt$4 ,ov]load-release devices on motor-/>t+ rheo/ats w n be consid]$ to take ! place ( ! cut-out requir$ by ?is section4 ,an automatic circuit-break] disconnect+ all wires ( ! circuit may s]ve z bo? swit* & cut-out4 ,auto />t]s1 unless equipp$ ) tight cas+s enclos+ all curr5t-c>ry+ p>ts1 9 all wet1 du/y1 or l9ty places1 mu/ be enclos$ 9 du/-tight1 firepro( cab9ets4 ,:]e !re is any liability ( %ort circuits across _! expos$ live p>ts be+ caus$ by accid5tal contacts1 a rail+ mu/ be erect$ ar\nd !m4 ,mu/ n be run 9 s]ies-multiple or multiple-s]ies1 except on con/ant-pot5tial sy/ems1 & !n only by special p]mission4 ,mu/1 :5 comb9$ ) ceil+ fans1 be hung f insulat$ hooks1 or else !re mu/ be an insulator int]pos$ betwe5 ! motor & its support4 ,mu/ ea* be provid$ ) a "n-plate1 giv+ ! mak]'s "n1 ! capacity 9 volts & amp]es1 & ! normal spe$ 9 revolutions p] m9ute4 ,all v>y+ 7or v>iable7 spe$ alt]nat+-curr5t motors except ^? us$ = railway s]vice mu/ be m>k$ ) ! maximum curr5t :i* !y c safely c>ry = #cj m9utes1 />t+ cold4 ,t]m9al blocks :5 us$ on motors mu/ be made ( approv$ non-combu/ible1 non-absorptive1 insulat+ mat]ial su* z slate1 m>ble1 or porcela94 ,adju/able-spe$ motors1 unless ( special & appropriate design1 if controll$ by means ( field regulation1 mu/ be s arrang$ & connect$ t !y _c be />t$ "u weak5$ field4 ,! use ( s(t rubb] bu%+s to protect ! lead wires com+ ?r\gh ! frames ( motors is p]mitt$1 except :5 in/all$ :]e oils1 grease1 oily vapors1 or o!r sub/ances kn[n to h rapid delet]i\s effect on rubb] are pres5t 9 su* quantities & 9 su* proximity to motors z may cause su* bu%+s to be liable to rapid de/ruction4 ,9 su* cases h>dwood prop]ly fill$1 or pref]ably porcela9 or micanite bu%+s mu/ be us$4 ,! foll[+ table %[s ! sizes ( wire recomm5d$ to be us$ ) motors ( ! horsep[] giv54 ,?is table is an extract f ! rules ( ! ,dep>tm5t ( ,gas & ,electricity ( ! ,city ( ,*icago4 ,! column head$ 8,ma9s0 may be us$ :5 !re are a numb] ( motors f$ by a s+le l9e4 ,= all l9es :i* supply a s+le motor only1 ! column head$ 8,bran*es0 mu/ be us$4 ,! diff]5ce betwe5 ! two is due to ! fact t x is n believ$ t sev]al motors f$ by a s+le l9e w all be />t$ at ! same "t2 h5ce x is n necess>y to provide ! ov]load capacity = all ( ! motors z x is :]e b a s+le motor is in/all$4 ,,table ,,viii4 ,,size ,,( ,,wires ,,= ,,motors ,,( ,,diff]5t ,,horse ,,p[]4 ,,direct ,,curr5t ---------------------------------------- -------------------------- #aaj ,volts #bbj ,volts ---------------------------------------- --------------------- ,h4 ,p4 ,full- ,size ( ,size ( ,full- ,size ( ,size ( load ,wire ,wire load ,wire ,wire ,curr5t ,ma9s ,bran*es ,curr5t ,ma9s ,bran*es ---------------------------------------- --------------------- #a #h #ad #ad #d #ad #ad #b #ae #ad #ab #h #ad #ad #c #bc #aj #h #ab #ad #ad #d #cj #h #f #ae #ad #ab #e #ch #f #f #ai #ab #aj #g4e #ef #e #d #bh #h #h #aj #ge #c #a #ch #f #f ---------------------------------------- --------------------- ,,s+le-,,phase ---------------------------------------- --------------------- #a #ab 444 #ab #f 444 #ad #b #bc 444 #h #aa 444 #ab #c #cc 444 #f #af 444 #aj #d #dd 444 #d #bb 444 #h #e #ec 444 #c #bf 444 #f ---------------------------------------- --------------------- ,,?ree-,,phase ---------------------------------------- --------------------- #a 444 444 444 #c #ad #ad #b 444 444 444 #e #ad #ad #c 444 444 444 #h #ad #ad #d 444 444 444 #aj #ad #ad #e 444 444 444 #ac #ad #ab #g4e 444 444 444 #ai #ab #h #aj 444 444 444 #bf #h #f ---------------------------------------- --------------------- ,music ,/&s4--,music /&s are us$ by ! musicians & are g5]ally plac$ betwe5 ! fir/ r[ ( seats & ! /age4 ,ea* musician %\ld be provid$ ) an individual /&1 al?\gh if necess>y1 two or ?ree c get along ) "o /&4 ,no fir/-class !at] %\ld be fitt$ up ) less ?an tw5ty outlets = musicians' lights4 ,9 ! ,metropolitan ,op]a ,h\se ( ,new ,york !re are "o hundr$4 ,h\ses us$ exclusively = vaudeville d n1 h[ev]1 ne$ t _m4 ,9 h\ses devot$ to gr& op]a1 (t5 z _m z "o hundr$ or m musicians are employ$ at ! same "t4 ,to take c>e ( su* a numb]1 ! music /&s %\ld be wir$ ) p9-plug connectors s t connections may be made f "o to ! o!r4 ,long flexible connections are necess>y = mo/ music /&s4 ,sometimes x is necess>y to cr[d ! or*e/ra "u ! /age & at o!r times1 ) musical com$ies1 = in/ance1 !y mu/ be br\ght out :]e !y c see ! movem5ts ( ! actors4 ,! m ! circuits are subdivid$1 & ! diff]5t lights made indep5d5t ( ea* o!r1 ! bett] x w be & ! less ! annoyance 9 case a fuse bl[s4 ,! fuses %\ld always be arrang$ at ! swit*bo>d s t x w n be necess>y = ! electrician to "w 9 front ( ! audi5ce 9 cases ( tr\ble4 ,= ?is reason extra /&s %\ld also be kept on h&4 ,a ma9 swit* controll+ ! lights %\ld be plac$ :]e "o ( ! musicians c h&le x4 ,9 d>k sc5es ^! lights mu/ (t5 be turn$ out4 ,if ^! lights are left "u ! control ( ! /age electrician !y w be m likely to be =gott5 at ! critical mom5t ?an if "u ! control ( ! m5 :o ne$ !m4 ,an eight c&le-p[] lamp = ea* /& w be suffici5t & ?is is usually plac$ inside a special reflector :i* all[s ! light to fall ^u ! music %eet only4 ,/age cable ( good quality %\ld be us$ = ! connections2 !re is too mu* r\gh h&l+ = re9=c$ cord4 ,! use ( ! ord9>y atta*m5t plug %\ld be avoid$2 use approv$ p9-plug connectors4 ,op5 ,"w4--,op5 "w is n all[$ 9 !at]s4 ,op]at+ ,room4--,see special *apt] on 8,op]at+ ,room40 ,panel ,bo>ds4--,panel bo>ds are really small swit*bo>ds1 ! swit*es & cut-outs be+ m\nt$ usually ^u slate4 ,! slate mu/ be free ( metal seams2 ^!1 if pres5t1 (t5 manife/ !mselves by heat+4 ,panel bo>ds1 unless locat$ 9 ! imm$iate vic9ity ( ! ma9 swit*bo>d1 & :]e !y are enclos$ 9 a comp>tm5t1 mu/ always be plac$ 9 /&>d metal cab9ets4 ,national ,electrical ,code ,rules = ,panel ,bo>ds4 ,! foll[+ specifications are int5d$ to apply to all panel & di/ribut+ bo>ds us$ = ! control ( light & p[] circuits1 b n to su* swit*bo>ds 9 c5tral /ations1 sub-/ations1 or isolat$ plants z directly control en]gy d]iv$ f g5]ators or trans=m+ devices4 ,design4 ,! specifications = con/ruction ( swit*es & cut-outs giv5 9 ! foll[+ pages mu/ be foll[$ z f> z !y apply4 ,9 ! relative arrangem5t ( fuses & swit*es1 ! fuses may be plac$ betwe5 ! bus-b>s & ! swit*es1 or betwe5 ! swit*es & ! circuits1 except 9 ! case ( s]vice swit*es4 ,:5 ! bran* swit*es are betwe5 ! fuses & ! bus-b>s1 ! connections mu/ be s arrang$ t ! blades w be dead :5 ! swit*es are op54 ,:5 !re are expos$ live-metal p>ts on ! back ( a bo>d1 a space ( at lea/ "o-half in* mu/ be provid$ betwe5 su* live metal p>ts & ! cab9et 9 :i* ! bo>d is m\nt$4 ,spac+s4 ,,table ,,ix4 ,,! ,,m9imum ,,di/ance ,,t ,,mu/ ,,be ,,ma9ta9$ ,,betwe5 ,,b>e ,,live ,,metal ,,p>ts 7,,bus-,,b>s1 ,,etc47 ---------------------------------------- -------------------- ,betwe5 ,p>ts ( ,opposite ,pol>ity1 ,except at ,swit*es & ,betwe5 ,l9k ,fuses ,p>ts ( -------------------------- ,same ,pol>ity ,:5 at ,l9k ,m\nt$ on ,:5 ,held ,fuses ! ,same ,free 9 ,air ,surface ---------------------------------------- ,n ov] #abe volts #c_/d in* #a_/b in* #a_/b in* ,n ov] #bej volts #a-a_/d in* #c_/d in* #c_/d in* ,n ov] #fjj volts #b in* #a-c_/d in* ---------------------------------------- ------------------- ,at swit*es or enclos$ fuses1 p>ts ( ! same pol>ity may be plac$ z close toge!r z conv5i5ce 9 h&l+ w all[4 ,x %\ld be not$ t ! above di/ances are ! m9imum all[able1 & x is urg$ t great] di/ances be adopt$ :]ev] ! conditions w p]mit4 ,! spac+s giv5 9 ! fir/ column apply to ! bran* conductors :]e enclos$ fuses are us$4 ,:]e l9k fuses or knife swit*es are us$1 ! spac+s mu/ be at lea/ z great z ^? giv5 9 ! foll[+ section on fuse spac+4 ,! spac+s giv5 9 ! second column above apply to ! di/ance betwe5 ! rais$ ma9 b>s & betwe5 ^! b>s & ! bran* b>s ov] :i* !y pass4 ,! spac+s giv5 9 ! ?ird column are int5d$ to prev5t ! melt+ ( a l9k fuse by ! bl[+ ( an adjac5t fuse ( ! same pol>ity4 ,panel bo>ds ( special design1 9 :i* ! insulation & sep>ation betwe5 ! bus-b>s1 & betwe5 ! o!r curr5t-c>ry+ p>ts is secur$ by means ( b>ri]s or insulat+ mat]ials in/ead ( by ! spac+s giv5 above1 mu/ be submitt$ = special exam9ation & approv$ be=e be+ us$4 ,fuse ,spac+s4 ,spac+s mu/ be at lea/ z great z ^? giv5 9 ,table ,x1 :i* applies only to pla91 op5 l9k fuses4 ,! spaces giv5 are correct = fuse blocks to be us$ on direct-curr5t sy/ems1 & c !re=e be safely foll[$ 9 devices design$ = alt]nat+ curr5ts4 ,if ! copp] fuse tips ov]hang ! edges ( ! fuse block t]m9als1 ! spac+s %\ld be measur$ betwe5 ! ne>e/ edges ( ! tips4 ,a space mu/ be ma9ta9$ betwe5 fuse t]m9als ( ! same pol>ity ( at lea/ "o-half ( an in* = voltages up to #abe & ( at lea/ ?ree-qu>t]s ( an in* = voltages f #abe to #bej4 ,?is is ! m9imum di/ance all[able1 & great] sep>ation %\ld be provid$ :5 practicable4 ,= #bej volts1 bo>ds1 or blocks ) ! ord9>y front-connect$ t]m9als1 except :]e ^! h a mass ( compact =m equival5t to ! back-connect$ t]m9als usually f\nd 9 swit*bo>d "w1 a sub/antial b>ri] ( insulat+ mat]ial1 n less ?an "o-eigh? ( an in* 9 ?ickness1 mu/ be plac$ 9 ! 8break0 gap--?is b>ri] to ext5d out f ! base at lea/ "o-eigh? ( an in* f>!r ?an any b>e live "p ( ! fuse-block t]m9al1 includ+ b9d+ screws1 nuts & ! l4 ,= ?ree-wire sy/ems cut-outs mu/ h ! break-di/ance requir$ = circuits ( ! pot5tial ( ! outside wires4 ,,table ,x4 ,,fuse ,,spac+s4 ---------------------------------------- ---------------- ,m9imum ,sep>ation ( ,m9imum ,ne>e/ ,metal ,p>ts ( ,break ,opposite ,pol>ity ,di/ance ,n ov] #abe volts3 ----------------------------------- #aj amp]es or less #c_/d in* #c_/d in* #aa-ajj amp]es #a in* #c_/d in* #aja-cjj amp]es #a in* #a in* #cja-a1jjj amp]es #a-a_/d in*es #a-a_/d in*es ---------------------------------------- ---------------- ,m9imum ,sep>ation ( ,m9imum ,ne>e/ ,metal ,p>ts ( ,break ,opposite ,pol>ity ,di/ance ,n ov] #bej volts3 ----------------------------------- #aj amp]es or less #a-a_/b in*es #a-a_/d in*es #aa-ajj amp]es #a-c_/d in*es #a-a_/d in*es #aja-cjj amp]es #b in*es #a-a_/b in*es #cja-a1jjj amp]es #b-a_/b in*es #b in*es ---------------------------------------- ---------------- ,swit* ,spac+s & ,dim5sions4 ,:5 design$ ) #bej-volt spac+s betwe5 adjac5t blades1 triple-pole swit*es mu/ be m>k$ #bej volts & may be us$ on #c-wire ,d4 ,c4 or s+le-phase sy/ems hav+ n m ?an #bej volts betwe5 adjac5t wires & n m ?an #ejj volts betwe5 ! two outside wires4 ,spac+s & dim5sions mu/ be at lea/ z great z ^? giv5 bel[3 ,,table ,,xi ,a4 ,,swit* ,,spac+s ,,& ,,dim5sions ,,= ,,swit*-,,bo>ds ,,& ,,panel ,,bo>ds4 ,n ,ov] #abe ,volts ,d4 ,c4 & ,a4 ,c4 ---------------------------------------- -------------------- ,m9imum ,sep>ation ( ,curr5t ,wid? & ,?ickness ,ne>e/ ,metal ,m9imum ---------------------------------- p>ts ( ,break ,blades ,clips & ,opposite ,di/ance ,h+es ,pol>ity ---------------------------------------- ------------------- #cj amp4 #a_/b in* by #a_/b in* by #a in* #c_/d in* #fj amp4 #e_/fd in* #c_/fd in* #a-a_/d in* #a-c_/d in* ---------------------------------------- ------------------- ,,table ,,xi ,b4 ,,swit* ,,spac+s ,,& ,,dim5sions ,,= ,,individual ,,swit*es4 ,n ,ov] #abe ,volts ,d4 ,c4 & ,a4 ,c4 ,in* ,in* ,in* ,in* #cj amp]es #a_/b by #e_/fd #a_/b by #c_/fd #a-a_/d #a #fj & #ajj amp]es #a-a_/b #a-a_/d #bjj amp]es #b-a_/d #b #djj & #fjj amp]es #b-c_/d #b-a_/b #hjj & #ajjj amp]es #c #b-c_/d ,a #cjj-;amp]e swit* ) ! spac+s ( ! #bjj-;amp]e swit* above may be us$ on swit*bo>ds4 ,,table ,,xi ,c4 ,,swit* ,,spac+s ,,& ,,dim5sions ,,= ,,all ,,swit*es4 #bej ,volts ,only ,d4 ,c4 & ,a4 ,c4 ,in* ,in* ,in* ,in* #cj amp]es #a_/b by #e_/fd #a_/b by #c_/fd #a-c_/d #a-a_/b ,,table ,,xi ,d4 ,,swit* ,,spac+s ,,& ,,dim5sions ,,= ,,all ,,swit*es4 ,n ,ov] #bej ,volts ,d4 ,c4 nor ,ov] #ejj ,volts ,a4 ,c4 ,in* ,in* ,in* ,in* #cj amp]es #e_/h by #a_/h #e_/h by #a_/af #b-a_/d #b #fj & #ajj amp]es #b-a_/d #b #bjj amp]es #b-a_/b #b-a_/d #djj & #fjj amp]es #b-c_/d #b-a_/b #hjj & #ajjj amp]es #c #b-c_/d ,a #cjj-;amp]e swit* ) ! spac+s ( ! #bjj-;amp]e swit* above may be us$ on swit*bo>ds4 ,cut-out t]m9als on swit*es = ov] #bej volts mu/ be design$ & spac$ = #fjj-volt fuses4 ,,table ,,xi ,e4 ,,swit* ,,spac+s ,,& ,,dim5sions ,,= ,,all ,,swit*es4 ,n ,ov] #fjj ,volts ,d4 ,c4 & ,a4 ,c4 ,in* ,in* ,in* ,in* #cj amp]es #e_/h by #a_/h #e_/h by #a_/af #d #c-a_/b #fj amp]es #d #c-a_/b #ajj amp]es #d-a_/b #d ,pa9t ,bridge4--,! pa9t bridge is usually a scaffold :i* c be rais$ & l[]$1 & :i* s]ves ! purpose ( c>ry+ sc5e pa9t]s at "w on ! curta9s4 ,a long /rip is ! be/ means ( illum9ation & x mu/ be connect$ ) long /age cable s z to be portable4 ,pa9t ,room4--,rooms 9 :i* pa9ts are /or$ %\ld n conta9 swit*es or cut-outs4 ,lamps %\ld be incas$ 9 vapor-tight globes4 ,program ,bo>d4--,a simple =m ( program bo>d is %[n 9 ,figure #afi4 ,except at ! top & ! bottom1 :]e ?ree lamps are %[n toge!r 9 "o comp>tm5t1 ea* lamp is incas$ by itself4 ,9 front ( ! lamps is usually color$ glass1 be>+ numb]s or lett]s4 ,! lamp beh9d any numb] be+ turn$ on1 t numb] becomes visible4 ,! top & bottom are usually label$1 8,special01 or 8,extra04 ,illu/ration3 ,,figure #afi4 ,ano!r =m ( program bo>d is %[n 9 ,figure #agj4 ,?is requires mu* m wir+4 ,ea* lamp on ! bo>d is connect$ to a plug or swit* at ! op]ator's /ation4 ,:i*ev] swit* is clos$ on ! small bo>d at ! "r causes a correspond+ light on ! l>ge bo>d to appe>4 ,illu/ration3 ,,figure #agj4 ,two program bo>ds are usually in/all$1 "o at ea* side ( ! /age1 fac+ ! audi5ce at angles1 s t "o c be se5 f ! extreme "r1 ! o!r f ! extreme left4 ,illu/ration3 ,,figure #aga4 ,a sy/em t is (t5 us$ = c>riage call is %[n 9 ,figure #aga4 ,! lights are arrang$ on circuits z indicat$ by numb]s4 ,all lamps be>+ ! same numb] be+ connect$ to "o wire lead+ to ! controll+ /ation4 ,?us !re are eight controll+ or swit* wires & !re is "o wire common to all4 ,a special swit* is provid$ :i* has a contact po9t = ea* wire4 ,pap] c>ds1 p]=at$ specially = ! numb]s !y repres5t1 are us$4 ,if a c>d be>+ a c]ta9 numb] is ins]t$ 9 ! prop] place & ! swit* clos$1 ! numb] pr9t$ on ! c>d w appe> on ! sign4 ,if1 = in/ance1 ! %ad$ circles 9 ! c>d at ! left ( ! figure all[ contact to be made1 ! lights indicat$ by black circles w light up & make ! figure 8#f04 ,ano!r =m ( program or call bo>d is %[n 9 ,figure #agb4 ,?is requires m wires ?an ! "o j describ$1 "o wire be+ c>ri$ to ! controll+ bo>d f ea* lamp4 ,! connections may be made 9 v>i\s ways4 ,sometimes !y are made ) knife swit*es4 ,if x is desir$ to make ! figure #a1 = in/ance1 only ! ?ree lights 9 a v]tical r[ 9 ! c5t] ne$ be light$1 & to d ?is ! ?ree wires f ^? lamps mu/ be connect$ to "o swit*4 ,to make ! figure #b1 sev5 lamps w\ld h to be lit by ano!r swit*4 ,x is capable ( mak+ any lett] or numb] & :5 us$ z a program bo>d only may be some:at simplifi$4 ,illu/ration3 ,,figure #agb4 ,9 connection ) ^! signs a l>ge numb] ( wires may be requir$ & att5tion %\ld be giv5 to ! foll[+ rule3 ,national ,electrical ,code ,rule = ,wir+ ,program & ,call ,bo>ds4 ,except 9 ! case ( /age pockets ! same conduit mu/ nev] conta9 m ?an f\r two-wire1 or ?ree ?ree-wire circuits ( ! same sy/em except by special p]mission1 & mu/ nev] conta9 circuits ( diff]5t sy/ems4 ,prosc5ium ,side ,lights4--,^! lights are locat$ on ea* side ( ! /age1 z ne> z possible to ! edge ( ! prosc5ium op5+ & (t5 9 front ( ! /eel curta94 ,!y are ( m use 9 musical productions1 :]e *oruses spread ov] ! :ole /age1 ?an 9 dramatic productions :]e ! int]e/ is m 9 ! c5t] ( ! /age4 ,9 "s !at]s ! prosc5ium side lights ext5d ! full height ( ! op5+ & are arrang$ = ?ree colors 9 ! same mann] z footlights & bord]s4 ,v (t51 h[ev]1 only t5 or twelve lights are arrang$ on ea* side ( ! /age4 ,! con/ruction rules are ! same z ^? gov]n+ foot-lights4 ,lamps mu/ be protect$ by /rong wire me%4 ,?is is ess5tial z 9 _m cases actors are v likely to back into !m :ile pass+ (f ! /age4 ,portable /rips are sometimes us$ z prosc5ium side lights4 ,receptacles4--,see 8,/age ,pockets04 ,retir+ ,rooms4--,9 ^! places a quiet subdu$ illum9ation is usually desir$4 ,!re are also (t5 qua9t objects & effects to be illum9at$4 ,a l>ge numb] ( outlets conv5i5tly locat$ = ! use ( table lamps1 fire places1 & illum9ation ( pictures1 %\ld be provid$4 ,rheo/ats4 ,national ,electrical ,code ,rules = ,rheo/ats4 ,location4 ,mu/ be plac$ on a swit*bo>d1 or at a di/ance ( at lea/ "o foot f combu/ible mat]ial1 or sep>at$ !refrom by a slab or panel ( non-combu/ible1 non-absorptive1 insulat+ mat]ial su* z slate1 soap/one1 or m>ble1 some:at l>g] ?an ! rheo/at1 :i* mu/ be secur$ 9 position indep5d5tly ( ! rheo/at supports4 ,bolts = support+ ! rheo/at %all be c\nt]sunk at lea/ "o-eigh? in* bel[ ! surface at ! back ( ! slab & ! bolt heads %all be cov]$ ) insulat+ mat]ial4 ,= prop] me*anical /r5g?1 slab %\ld be ( a ?ickness consi/5t ) ! size & weight ( ! rheo/at1 & 9 no case to be less ?an "o-half in*4 ,if resi/ance devices are in/all$ 9 rooms :]e du/ or combu/ible fly+s w\ld be liable to accumulate on !m1 !y mu/ be equipp$ ) du/-pro( face plates4 ,mat]ials4 ,mu/ be made entirely ( non-combu/ible mat]ials1 except su* m9or p>ts z h&les1 magnet insulation1 etc4 ,all segm5ts1 lev] arms1 etc41 mu/ be m\nt$ on non-combu/ible1 non-absorptive1 insulat+ mat]ial4 ,connections4 ,clamps = connect+ wires to ! t]m9als mu/ be s design$ z to insure a ?or\ghly good connection & mu/ be suffici5tly /rong & heavy to )/& h>d usage4 ,= curr5ts above #cj amp]es1 lugs into :i* ! connect+ wires may be sold]$1 or approv$ sold]less connectors mu/ be us$4 ,clamps or lugs w n be requir$ :5 leads are provid$ z a "p ( ! device4 ,no-,voltage ,release4 ,motor-/>t+ rheo/ats mu/ be s design$ t ! contact arm _c be left on int]m$iate segm5ts1 & = direct-curr5t circuits mu/ be provid$ ) an automatic device :i* w int]rupt ! supply circuit be=e ! spe$ ( ! motor falls to less ?an "o-?ird ( its normal value4 ,9 motor-/>t+ rheo/ats = alt]nat+-curr5t circuits ! automatic int]rupt+ device may be omitt$4 ,ov]load ,release4 ,ov]load-release devices :i* are inop]ative dur+ ! process ( />t+ a motor w n be approv$1 unless o!r circuit-break]s or fuses are in/all$ 9 connection ) !m4 ,signals4--,signals are necess>y betwe5 ! manag]'s (fice & ! /age electrician's /ation2 = ?is purpose telephones are g5]ally us$4 ,9 _m cities a fire-al>m signal sy/em is also requir$ & x is specifi$ to :at "p ( ! h\se x %all lead4 ,9 addition to ! above1 a means ( signall+ ! fly floor & ! or*e/ra lead] mu/ be provid$4 ,buzz]s are us$ = ^! signals4 ,x is be/ to use batt]ies = all ^! signals in/ead ( attempt+ to run !m f light+ circuits4 ,means ( signall+ ! arc-lamp /ation 9 ! gall]y or ! balcony %\ld also be provid$ = use 9 connection ) lant]n slides1 etc4 ,telephone connection to ?is po9t w also be v useful 9 ord] to give in/ructions to ! lamp op]ator4 ,return-call sy/ems are advisable 9 all places s t ! electrician c be call$ f any po9t4 ,9 "s cities ! local laws require ^! wires to be 9 conduit s z to preclude any possibility ( _! communicat+ fire to any?+4 ,at any rate ! wires %\ld be v c>efully in/all$4 ,signs4--,9 ne>ly all electric signs us$ ab\t !at]s ! lett]s are outl9$ by inc&esc5t lamps4 ,small c&le-p[] lamps are always us$4 ,!y are n only economical b mu* m attractive because ! gl>e f too mu* light is v annoy+4 ,_m signs are equipp$ ) l[ c&le-p[] tung/5 lamps wir$ 9 s]ies4 ,9 ord] t ! lett]s %\ld %[ to full advantage !y %\ld be glossy :ite & be kept clean4 ,su* lett]s w %[ z bright z ! lamps4 ,x is be/ to wire ! sign s t ei!r side c be us$ indep5d5t ( ! o!r4 ,9 _m cases1 also1 signs are wir$ s t ea* lett] is indep5d5t ( ! o!rs = use ) fla%]s4 ,attraction signs are us$ to adv]tise ! attractions :i* appe> f "t to "t4 ,indep5d5t portable lett]s are us$ & *ang$ z (t5 z ! attractions *ange4 ,ea* lett] mu/ be fitt$ ) cable & atta*m5t plug ( "s k9d & %\ld h a sep>ate circuit4 ,cut-outs are g5]ally locat$ on ! frame & mu/ be protect$ f ! wea!r4 ,sockets4--,sockets mu/ be ( approv$ con/ruction4 ,key sockets mu/ n be us$ = em]g5cy or exit light+4 ,sockets ) fib] l9+s mu/ n be us$ unless protect$ by insulat+ jo9ts4 ,9 damp places wea!rpro( sockets mu/ be us$4 ,:]e inflammable gases exi/1 lamps mu/ be incas$ 9 vapor-pro( globes4 ,porcela9 sockets %\ld n be us$ 9 !at]s4 ,wea!rpro( sockets are g5]ally us$ = portable purposes because !y h no screws1 etc41 to "w loose4 ,/age ,cable4--,/age cables are all[$ 9 !at]s only :]e flexible conductors are absolutely necess>y4 ,all wir+ t c possibly be in/all$ 9 conduit or /rip con/ruction %\ld be s arrang$4 ,by ! use ( plugg+ boxes ! quantity ( /age cable necess>y c be mu* r$uc$4 ,plugs = arc & inc&esc5t lights mu/ n be int]*angeable4 ,/age ,flues4--,9 mo/ cities /age flues1 z describ$ 9 ! *apt] on 8,!at] ,build+s01 are requir$4 ,! requirem5t is also1 (t51 t !y be releas$ by electrical means4 ,! rule bel[ contemplates a circuit conta9+ an electro-magnet & at lea/ two swit*es 9 s]ies4 ,! magnet mu/ be en]giz$ to hold ! v5tilator clos$4 ,if ! curr5t fails or a swit* is op5$ ! damp]s mu/ fly op5 at once4 ,:]e direct curr5t is available ! magnet is usually w\nd = #aaj volts & connect$ to a circuit t is always alive4 ,9 case ( an isolat$ plant :i* is %ut d[n at night "s arrangem5t = ty+ ! damp]s d[n %\ld be made1 b x is n always advisable1 z once ti$ !y are likely to rema9 s & sure to fail :5 ne$$4 ,magnets d n "w well on alt]nat+ curr5ts & 9 su* cases ! magnet %\ld be w\nd = a small curr5t to be obta9$ f a gravity batt]y :i* may be all[$ to be always work+4 ,locate ! batt]y :]e x w n freeze4 ,national ,electrical ,code ,rules = ,control ( ,/age ,flues4 ,9 cases :]e damp]s are releas$ by an electric device1 ! electric circuit op]at+ same mu/ be normally clos$4 ,magnet op]at+ damp]s mu/ be w\nd to take full voltage ( circuit by :i* x is suppli$1 us+ no resi/ance device1 & mu/ n heat m ?an normal = app>atus ( simil> con/ruction4 ,x mu/ be locat$ 9 l(t above sc5]y1 & be in/all$ 9 a suitable iron box ) a tight1 self-clos+ door4 ,su* damp]s mu/ be controll$ by at lea/ two /&>d s+le-pole swit*es m\nt$ )9 approv$ iron boxes provid$ ) self-clos+ doors )\t lock or lat*1 & locat$1 "o at ! electrician's /ation & ! o!rs z designat$4 ,/age & ,gall]y ,pockets4--,/age pockets are usually locat$ on ea* side ( ! /age j f> en\gh f ! c5t] to be safely back ( ! sc5]y4 ,! m pockets !re are ! bett] x w be4 ,ea* pocket usually conta9s f\r circuits1 & "o ( ^! at lea/ %\ld be = inc&esc5t lights4 ,x w be conv5i5t if ! /age pockets are divid$ into f\r gr\ps1 ea* gr\p "u control ( a sep>ate swit* & ! :ole aga9 "u control ( a ma9 swit*4 ,?is w enable ! op]ator to ?r[ (f all ( ! pockets at once1 if necess>y1 or to make any comb9ation desir$4 ,illu/ration3 ,,figure #agc4 ,sometimes lights f$ ?r\gh /age pockets require to be dimm$2 b x is h>dly practicable to arrange dimm]s = app>atus c>ri$ by travel+ companies1 s9ce a dimm] mu/ be select$ ) respect to ! amp]age x is to control4 ,9 addition to ! rules giv5 bel[1 "s cities require ! bottom ( /age pockets to be op51 s z to avoid an accumulation ( du/4 ,?is is a v ess5tial precaution1 z o!rwise ! pockets soon fill up or require v frequ5t clean+4 ,! cov]s mu/ be sub/antial z heavy trucks are sometimes run ov] !m4 ,two illu/rations ( /age pockets are giv5 9 ,figures #agc & #agd4 ,! plugs us$ ) ^! boxes are %[n 9 ,figure #age4 ,illu/ration3 ,,figure #agd4 ,illu/ration3 ,,figure #age4 ,gall]y pockets are n usually laid 9 ! floor b along ! rail+4 ,! gall]y pockets %\ld be "u sep>ate control f ! /age swit*bo>d4 ,national ,electrical ,code ,rules = ,/age & ,gall]y ,pockets4 ,mu/ be ( approv$ type1 insulat$ f gr\nd & controll$ f swit*bo>d1 ea* receptacle to be ( n less ?an #ce-;amp]e rat+ = arc lamps nor #ae-;amp]e = inc&esc5t lamps1 & ea* receptacle to be wir$ to its full capacity4 ,arc pockets to be wir$ ) wire n small] ?an ,no4 #f ,b4 ,s4 gauge & inc&esc5t pockets ) n less ?an ,no4 #ab ,b4 ,s4 gauge4 ,plugs = arcs & inc&esc5t pockets mu/ n be int]*angeable4 ,swit*es4--,all knife swit*es %\ld be enclos$ 9 cab9ets unless !y are locat$ on a swit*bo>d4 ,9 expos$ places1 flu% swit*es %\ld be us$4 ,! usual height at :i* scatt]$ swit*es are locat$ is ab\t f\r & "o-half feet above floor4 ,door swit*es are ( use pr9cipally 9 dress+ rooms4 ,illu/ration3 ,,figure #agf4 ,diagrams ( ?ree-way swit*es are giv5 9 ,figures #agf & #agg4 ,9 ,figure #agg1 ! wir+ by :i* a light c be controll$ f ?ree diff]5t po9ts is %[n4 ,! middle swit* mu/ be a pole-*ang+ swit*4 ,9 ?is case a ?r[-ov] knife swit* is wir$ to p]=m ?is function4 ,omitt+ ! knife swit* we h two ?ree-way swit*es controll+ ! light4 ,:5 bo? swit*es 7indicat$ by brok5 l9es7 connect to ! same wire ! light burns4 ,illu/ration3 ,,figure #agg4 ,9 ,figure #agf1 :5 bo? swit*es connect to ! same pol>ity ! light is out2 :5 "o ( !m is connect$ to ! o!r pole ! light burns4 ,"u c]ta9 conditions ?is arrangem5t is m economical 9 wire b has ! disadvantage :i* ! o!r me?od avoids1 ( br++ bo? poles to ea* swit*4 ,?is me?od _c be us$ ) direct-curr5t arc lamps4 ,?ree-way swit*es are useful on /airways1 enabl+ "o to turn on a light at ! bottom ( ! /airway & turn x (f :5 at ! top or vice v]sa4 ,national ,electrical ,code ,rules = ,swit*es & ,connections4 ,swit*es4 ,mu/ be plac$ on all s]vice wires1 ei!r ov]head or und]gr\nd1 9 ! ne>e/ readily accessible place to ! po9t :]e ! wires ent] ! build+1 & arrang$ to cut (f ! entire curr5t4 ,dep>ture f ?is rule may be au?oriz$ only "u special p]mission 9 writ+4 ,swit*es controll+ em]g5cy light+ mu/ be locat$ only 9 ! lobby4 ,mu/ :5 us$ = s]vice swit*es1 indicate1 on inspection1 :e!r ! curr5t be 8on0 or 8(f04 ,swit* cab9ets mu/ be deep en\gh to all[ ! door to be clos$ :5 #cj amp]e bran*-circuit swit*es are 9 any position1 & :5 l>g] s+le-?r[ swit*es are ?r[n op5 z f> z _! con/ruction & in/allation w p]mit4 ,mu/1 = con/ant-curr5t sy/ems1 close ! ma9 circuit & disconnect ! bran* wires :5 turn$ 8(f02 mu/ be s con/ruct$ t !y %all be automatic 9 action1 n /opp+ betwe5 po9ts :5 />t$1 & mu/ prev5t an arc betwe5 ! po9ts "u all circum/ances4 ,!y mu/ indicate :e!r ! curr5t be 8on0 or 8(f04 ,s]vice cut-out & swit* mu/ be arrang$ to cut (f curr5t f all devices includ+ met]s4 ,mu/ always be plac$ 9 dry1 accessible places1 & be gr\p$ z f> z possible4 ,s+le-?r[ knife swit*es mu/ be s plac$ t gravity w n t5d to close !m4 ,d\ble-?r[ knife swit*es may be m\nt$ s t ! ?r[ w be ei!r v]tical or horizontal z pref]r$1 b if ! ?r[ be v]tical a lock+ device mu/ be provid$1 s con/ruct$ z to insure ! blades rema9+ 9 ! op5 position :5 s set4 ,:5 practicable swit*es mu/ be s wir$ t blades w be 8dead0 :5 ! swit* is op54 ,:5 swit*es are us$ 9 rooms :]e combu/ible fly+s w\ld be likely to accumulate ar\nd !m1 !y mu/ be enclos$ 9 du/-tight cab9ets4 ,up to #bej volts & ?irty amp]es1 approv$ indicat+ snap swit*es are sugge/$ 9 pref]5ce to knife swit*es on light+ circuits4 ,s+le-pole swit*es mu/ nev] be us$ z s]vice swit*es nor = ! control ( outdoor signs or circuits locat$ 9 damp places1 nor plac$ 9 ! neutral wire ( a ?ree-wire sy/em1 except 9 ! two-wire bran* or tap circuit supply+ n m ?an #ffj watts4 ,:]e flu% swit*es or receptacles are us$1 :e!r ) conduit sy/ems or n1 !y mu/ be enclos$ 9 an approv$ box con/ruct$ ( iron or /eel1 9 addition to ! porcela9 enclosure ( ! swit* or receptacle4 ,h+es ( knife swit*es mu/ n be us$ to c>ry curr5t unless !y are equipp$ ) spr+ wa%]s1 held by lock-nuts or p9s1 or _! equival5t1 s arrang$ t a firm & secure connection w be ma9ta9$ at all positions ( ! swit* blades4 ,spr+ wa%]s mu/ be ( suffici5t /r5g? to take up any we> 9 ! h+e & ma9ta9 a good contact at all times4 ,connections4 ,swit*es = curr5ts ( ov] ?irty amp]es mu/ be equipp$ ) lugs1 firmly screw$ or bolt$ to ! swit*1 & into :i* ! conduct+ wire %all be sold]$4 ,= ! small] siz$ swit*es simple clamps c be employ$1 provid$ !y are heavy en\gh to /& consid]able h>d usage4 ,:]e lugs are n provid$1 a rugg$ d\ble-,v groove clamp is advis$4 ,a set screw gives a contact at only "o po9t1 is m likely to become loos5$1 & is almo/ sure to cut into ! wire4 ,= ! small] sizes1 a screw & wa%] connection ) up-turn$ lugs on ! swit* t]m9al gives a satisfactory contact4 ,spac+s4 ,see 8,panel ,bo>ds04 ,swit*bo>ds4--,! /age swit*bo>d is usually locat$ on ! "r-h& side ( ! /age4 ,?is position enables ! op]ator to wat* cues easily & h&le 8 swit*es ) ! "r h&4 ,?is side is also ! "o f :i* ! /age manag] pref]s to "w4 ,x is pref]able to h ! bo>d rais$ high en\gh above /age level to all[ all space on ! /age to be us$ by actors4 ,if ! swit*bo>d is locat$ on /age level x takes up mu* room t is valuable & makes /age exits = actors difficult4 ,! wir+ ( a good swit*bo>d %\ld be divid$ into ?ree p>ts1 ea* "p indep5d5t ( ! o!rs1 s t any "o "p c be entirely cut (f )\t int]f]+ ) ! o!r4 ,all ( ! h\se lights %\ld be f$ ?r\gh "o ma9 swit*1 & all ( ! /age light connect$ to ano!r set ( bus-b>s1 b x is be/ n to h ! /age side ( ! bo>d z a :ole controll$ by a ma9 swit*4 ,if ! /age side ( ! bo>d is controll$ by a s+le swit* !re exi/s ! possibility t ?is swit* may be us$ to cut (f ev]y?+ = a d>k sc5e & :5 light is aga9 want$ a "p ( ! light+ ( ! previ\s sett+ may be left on & possibly int]f]e ) ! new sc5e4 ,illu/ration3 ,,figure #agh4 ,! /age light+ is usually divid$ into f\r gr\ps1 viz43 ?ree color gr\ps & a gr\p ( /age pockets4 ,! numb] ( :ite lights is usually equal to t ( all ( ! colors4 ,figure #agh %[s a well laid out swit*bo>d4 ,all ( ! lights 9 ! auditorium are controll$ by swit*es %[n 9 ! upp] "r-h& corn] & all ( ^! are "u ! control ( ! ma9 swit*4 ,! h\se lights are usually ?r[n on or (f z a :ole & ?is ma9 swit* mu/ be conv5i5t = ! op]ator4 ,! /age pockets are controll$ by ! bank ( swit*es %[n at ,e4 ,lights burn+ (f ! /age pockets g5]ally are controll$ by special op]ators on ! /age or by actors1 & ne$ n be s v conv5i5t to ! swit*bo>d op]ator4 ,!y mu/1 h[ev]1 be "u 8 control :5 necess>y2 b "h also a ma9 swit* is n advisable4 ,9 addition to ! ?ree gr\ps ( lights spok5 ( above1 !re are a numb] ( lights :i* %\ld be controll$ f ! swit*bo>d b mu/ be s connect$ t !y w be left on1 no matt] :at is done ) ei!r h\se or /age light4 ,9 ?is gr\p belong a few lights m\nt$ at ! top ( ! swit*bo>d :i* enable ! op]ator to see 8 swit*es :5 all else is d>k4 ,^! lights are g5]ally %ield$ s z to ?r[ no light 9 ! direction ( ! /age op5+4 ,! or*e/ra lights also belong 9 ?is gr\p1 b a special swit* may1 ) advantage1 be arrang$ on ?is circuit to br+ x "u ! control ( "o ( ! musicians4 ,9 "s d>k sc5es ^! lights are turn$ out = a %ort "t1 b x is v important t !y be turn$ on aga9 at ! prop] mom5t1 & ?is is m c]ta9ly assur$1 by giv+ ! musicians control1 ?an by leav+ x to an electrician on ! /age :o may be v busy ) o!r matt]s at ! "t4 ,! lights on ! fly floor & 9 ! rigg+ l(t1 z well z ^? 9 dress+ rooms & basem5t1 mu/ also be indep5d5t4 ,fan motor circuits %\ld also be indep5d5t ( ! h\se circuit4 ,!y are (t5 ne$$ :5 ! h\se lights are ?r[n (f4 ,) ! swit*bo>d illu/rat$ 9 ,figure #agh we h %[n only ! swit*es gov]n+ ! h\se & /age prop]4 ,! swit*es gov]n+ ! o!r lights are usually work$ into ! vacant spaces betwe5 ! two gr\ps4 ,ea* swit* %\ld be label$ 9 su* a mann] t a new op]ator c le>n ! bo>d easily4 ,! mo/ important "p ( ! bo>d is t "p gov]n+ ! /age light+1 & ?is %\ld always be plac$ z conv5i5tly z possible to ! op]ator4 ,a /age swit*bo>d is l a h\se 9 t no "o is :olly satisfi$ ) ! "o he has1 b ?9ks he c\ld improve x a little if he c\ld build x ov] aga94 ,! arrangem5t %[n 9 ,figure #agh is1 h[ev]1 q satisfactory = g5]al purposes4 ,! :ite lights pr$om9ate 9 ! ratio ( two to "o & are laid out 9 two gr\ps ,a & ,b4 ,bo? gr\ps are controll$ by ! swit* ,c4 ,! swit*es ,a & ,b d n control ! lights at all if ! small] ?r[-ov] swit*es at ! "r are ?r[n d[nw>d4 ,a diagram ( ^! swit* connections is giv5 9 ,figure #agi :]e ! swit*es ,b & ,c are indicat$4 ,! object ( ! swit*es ,a & ,b is to help 9 quickly increas+ or decreas+ ! illum9ation on ! /age4 ,if 9 ! beg9n+ ( a c]ta9 sc5e1 = in/ance1 only a small quantity ( light is want$1 :ile a little lat] full illum9ation is desir$1 ! l[ illum9ation may be obta9$ by ?r[+ ! prop] swit*es d[n2 ! additional illum9ation :i* w be ne$$ a few m9utes lat] may be prep>$ = by sett+ ! o!r swit*es ne$$ to ! upw>d position & at ! prop] mom5t clos+ swit* ,b2 ?is w in/antly produce ! effect :i* o!rwise w\ld be possible only by op]at+ a numb] ( swit*es 9 succession4 ,9 ! same way1 by a rev]sal ( ?is process1 ! illum9ation may be r$uc$ 9 any am\nt4 ,?is feature is v valuable 9 _m /age sett+s4 ,illu/ration3 ,,figure #agi4 ,to ?r[ (f all ( ! :ite lights ! swit* ,c mu/ be op5$4 ,! swit*es ,d & ,f are ma9 swit*es controll+ color$ lamps4 ,all lamps ( "o color %\ld be connect$ to "o or ! o!r ( ^! gr\ps unless "s special color effect is desir$4 ,f ! ?ree gr\ps ( swit*es1 circuits ext5d into ! foot lights1 into e bord]1 & into ! prosc5ium side-light /rips s t ! color s*eme may be c>ri$ out 9 any ( ^!4 ,! h&les ( all swit*es 9 a r[ %\ld be ( ! same height s t ! op]ator may m readily accu/om himself to cat* !m quickly4 ,x is bett] to h swit*es ( "s excess capacity1 z ! heavy metal /&s ! arc+ mu* bett]4 ,a ma9 swit* by :i* ! :ole bo>d may be cut (f %\ld be in/all$ b ?is ne$ n be on ! front ( ! bo>d4 ,,*apt] ,,xix4 ,,portable ,,/age ,,equipm5t4 ,! g5]al rule is t all wires 9 !at]s mu/ be 9 conduit or armor$ cable4 ,metal mold+ is n consid]$ suitable = ! /age side ( ! !at]4 ,!re are1 h[ev]1 /age requirem5ts :i* make ! use ( "s sort ( flexible & portable connection necess>y & = su* purposes /age cables are all[$4 ,all wir+ t c be p]man5tly fa/5$ to batt5s or fa/5$ 9 o!r ways2 or t is run inside ( po/s or /atu>y1 mu/ be 9 conduit or armor$ cable4 ,! ,national ,electrical ,code ,rules are quot$ 9 ?is *apt] :]ev] !y apply & %\ld be foll[$1 n only because ^! rules outl9e ! be/ practice b because1 ?r\gh\t ! c\ntry1 inspections w g5]ally be gov]n$ by ^! requirem5ts4 ,ev5 :]e ! local rules v>y some:at f ^! rules1 x w be f\nd t all app>atus con/ruct$ accord+ to !m w be favor$ to a consid]able ext5t4 ,anvil ,sp>ks4--,^! are sometimes produc$ by arrang+ ! anvil z "o pole ( a circuit & ! hamm] z ! o!r4 ,:5 ! hamm] leaves ! anvil1 ! sp>k occurs4 ,a resi/ance mu/ always be ins]t$ 9 ! circuit if a light or p[] circuit is employ$4 ,"o ( ! mo/ successful me?ods ( produc+ anvil sp>ks is %[n 9 ,figure #ahj4 ,:5 ! hamm] /rikes ! anvil ! spr+ foll[s & /rikes ! head ( ! hamm]2 & :5 x reb\nds ! sp>k occurs4 ,if x is n desir$ to use a p[] circuit ! sp>k may be obta9$ f batt]ies by ! use ( a sp>k coil4 ,sp>ks 9 duel+ sc5es may be produc$ 9 mu* ! same mann]4 ,9 "s cities ! inspection laws require all arcs or sp>ks1 us$ on ! /age1 to be enclos$4 ,s f> z ! au?ors are aw>e no really satisfactory me?od ( enclos+ anvil sp>ks has ev] be5 made up4 ,if su* an enclosure is to be con/ruct$ x mu/ be borne 9 m9d t x mu/ n spoil ! illusion nor m> ! tone 9 case ! anvil is tun$ = use 9 s++ acts4 ,a special comb9ation ( metals is on sale at /age-supply deal]s by :i* sp>ks c be produc$ )\t ! use ( curr5t4 ,illu/ration3 ,,figure #ahj4 ,arc ,lamps4--,9 ,figure #aha1 !re is %[n an op5 or flood lamp1 also kn[n z ! 8,olivet04 ,?is /yle ( lamp is us$ on ! /age only = g5]al illum9ation4 ,z ! light f ?is lamp spreads 9 all directions x mu/ be br\ght close to ! "p to be illum9at$ & ?is usually br+s x close to ! sc5]y4 ,all portable /age lamps are h& fe$ & require close att5tion on ! "p ( op]ators4 ,:ile travel+ x sometimes occurs t only high voltage su* z #ejj or #fjj volts is available & 9 su* a case a suitable numb] ( lamps mu/ be connect$ 9 s]ies4 ,h&-fe$ arc lamps are difficult to />t "u su* circum/ances & ! foll[+ me?od is (t5 resort$ to3 ,place ! c>bons ( all ! lamps connect$ 9 s]ies ! prop] di/ance ap>t & connect a small fuse across ea* gap4 ,:5 ! curr5t is turn$ on x w melt ! fuses & e/abli% ! arc4 ,illu/ration3 ,,figure #aha4 ,illu/ration3 ,,figure #ahb4 ,9 ,figure #ahb we h an illu/ration ( :at is kn[n z ! spot or l5s lamp4 ,?is /yle ( lamp is us$ on ! /age1 on bridges1 or 89 front0 79 front be+ ! t]m by :i* ! balcony or gall]ies are designat$ 9 ?is case74 ,9 ! figure a 8,sciopticon0 atta*m5t is %[n :i* is removable4 ,ev5 v unpret5ti\s %[s c>ry at lea/ "o spot lamp & ! l>ge/ %[s (t5 c>ry #cj or #dj op5 & spot lamps4 ,arc lamps are (t5 imitat$ by an inc&esc5t lamp plac$ )9 a suitable globe ) ! hood made up 9 ! %ape ( an arc lamp4 ,illu/ration3 ,,figure #ahc4 ,figure #ahc is a cut ( a /]eopticon outfit4 ,dissolv+ views require at lea/ two lamps & sometimes ?ree1 ! ?ird be+ = ! purpose ( provid+ a frame = ! views or add+ an extra effect1 su* z fall+ sn[4 ,two lamps at lea/ are always 9 use at ! same "t & x is necess>y to provide cables ( suffici5t c>ry+ capacity = two or ?ree lamps1 z ! case may be4 ,! ,national ,electrical ,code ,rules = ,arc ,lamps to be ,us$ on ! ,/age4 ,mu/ be con/ruct$ entirely ( metal except :]e ! use ( approv$ insulat+ mat]ial is necess>y4 ,mu/ be sub/antially con/ruct$1 & s design$ z to provide = prop] v5tilation1 & to prev5t sp>ks be+ emitt$ f lamps :5 same are 9 op]ation2 & mica mu/ be us$ = frame insulation4 ,front op5+ mu/ be provid$ ) self-clos+ h+$ door frame1 9 :i* wire gauze or glass mu/ be ins]t$1 except 9 ! case ( l5s lamps1 :]e ! front may be /ation>y1 & a solid door be provid$ on back or side4 ,mu/ be s con/ruct$ t nei!r c>bons nor live p>ts w be br\ght into contact ) metal ( hood dur+ op]ation1 & arc-lamp frames & /&>ds mu/ be s in/all$ & protect$ z to prev5t ! liability ( _! be+ gr\nd$4 ,swit* on /&>d mu/ be s con/ruct$ t accid5tal contact ) any live portion ( same w be impossible4 ,all /r&$ connections 9 lamp & at swit* & rheo/at mu/ be provid$ ) approv$ lugs4 ,rheo/ats mu/ be pla9ly m>k$ ) _! rat$ capacity 9 volts & amp]es1 &1 if m\nt$ on a /&>d1 mu/ be rais$ to a height ( at lea/ ?ree in*es above ! floor4 ,resi/ance mu/ be enclos$ 9 a sub/antial & prop]ly v5tilat$ metal case :i* af=ds a cle>ance ( at lea/ "o in* betwe5 ! case & ! resi/ance elem5t4 ,a compet5t op]ator mu/ be 9 *>ge ( ea* arc lamp1 except t "o op]ator may h *>ge ( two lamps1 :5 !y are n m ?an t5 feet ap>t & are s locat$ t he c prop]ly wat* & c>e = bo? lamps4 ,ea* lamp %\ld be provid$ ) its own fuses & swit*4 ,baby ,spot ,lamp4--,?is is ! "n giv5 to a small l5s lamp 9 :i* an inc&esc5t lamp is us$ in/ead ( an arc lamp4 ,su* a lamp _c be us$ = projection v well b is well suit$ to illum9ate p>ts ( an act t d n require v bright illum9ation4 ,x is sometimes us$ to take ! place ( prosc5ium side lights4 ,9 "o well-kn[n production twelve su* lamps 7 us$ ^u scaffold+ directly above ! prosc5ium op5+4 ,! inc&esc5t lamp is movable = ! purpose ( focus+2 b x n be+ a 8po9t s\rce01 no su* accurate focus+ is possible z ) arc lamps4 ,batt]ies4--,bo? prim>y & second>y1 or /orage1 batt]ies are ext5sively us$ ^u ! /age4 ,small dry cells are (t5 us$ to r+ bells or light m9iature lamps 9 ! hair or clo!s ( ! *orus4 ,! electromotive =ce ( a cell is indep5d5t ( ! size & dep5ds only ^u ! mat]ials us$2 b ! curr5t :i* a batt]y c deliv] v>ies directly ) its size4 ,if we wi% to increase ! voltage we mu/ connect sev]al cells 9 s]ies1 z indicat$ 9 ,figure #ahd2 if we h suffici5t voltage b lack curr5t we mu/ connect1 z 9 ,figure #ahe4 ,z a g5]al rule1 9 any circuit1 we mu/ connect ! batt]y s t its resi/ances %all mo/ ne>ly equal ! resi/ance ( ! device :i* x fe$s4 ,?is means t if ! resi/ance ( ! device is great] ?an t ( ! batt]y we mu/ connect our batt]y 9 s]ies2 if x is less we mu/ connect ! cells 9 multiple1 z indicat$ by ,figure #ahe4 ,:5 connect+ cells 9 multiple ^? ( ! same k9d %\ld always be select$4 ,any cell ^: electromotive =ce is n fully equal to ! o!rs w absorb en]gy & be *>g$ by ! o!rs4 ,! resi/ance ( small cells is high & x is be/1 :]e size is n objectionable1 to use l>ge cells4 ,/orage1 or second>y batt]ies1 h l[ resi/ance & are capable ( deliv]+ v /rong curr5ts1 ev5 ?\gh ! voltage be l[4 ,! heat is proportional to ! squ>e ( ! curr5t & a c]ta9 amp]age1 ) two volts back ( x1 w produce j z mu* heat 9 giv5 resi/ance z ! same amp]age ) sev]al hundr$ volts4 ,! sp>k+ 9 case ( a brok5 circuit or a fuse bl[+ w\ld1 h[ev]1 be h>dly noticeable ) ! l[ voltage4 ,illu/ration3 ,,figure #ahd4 ,illu/ration3 ,,figure #ahe4 ,no def9ite rule is giv5 conc]n+ ! fus+ ( l[-voltage /orage batt]ies1 b x is good practice to ins]t a d\ble-pole fuse 9 ea* bran* circuit2 ! fuse to be small en\gh to protect ! smalle/ wire f$ ?r\gh x4 ,! capacity ( /orage batt]ies is usually giv5 9 8amp]e h\rs04 ,a #fj-;amp]e-h\r batt]y1 = in/ance1 c deliv] ?ree amp]es = tw5ty h\rs or t5 amp]es = six h\rs4 ,) e batt]y !re is1 h[ev]1 a c]ta9 maximum rate ( dis*>ge :i* %\ld n be exce$$4 ,! batt]y %\ld n be all[$ to run d[n too l[ & %\ld be kept well *>g$4 ,x is be/ to foll[ ! in/ructions :i* ! mak]s s5d out ) !m4 ,bells4--,electric bells are us$ on ! /age = _m purposes4 ,sometimes !y are us$ z musical in/rum5ts1 ! gongs be+ prop]ly tun$2 at o!r times !y are provid$ to r+ 9 connection ) c]ta9 acts2 & !y are also us$ = ! purpose ( signal+4 ,:5 signals are to be giv51 :i* ! audi5ce mu/ n he>1 x is bett] to provide buzz]s4 ,illu/ration3 ,,figure #ahf4 ,bells c be arrang$ to op]ate f p[] circuits by plac+ an inc&esc5t lamp1 or "s o!r suitable resi/ance1 9 s]ies ) !m2 b x is n advisable to d s4 ,x is n safe f a fire-haz>d po9t ( view1 & also n v practical1 s9ce 9 _m places alt]nat+ curr5t only c be _h & ! ord9>y bell does n op]ate well ) x4 ,batt]ies %\ld always be us$ = bells & o!r l[-voltage devices4 ,:]e x is desir$ to op]ate a numb] ( bells toge!r1 !y may be arrang$ 9 s]ies1 z %[n 9 ,figure #ahf1 9 :i* ! vibrator ( "o bell is cut out ( circuit s t ! vibrations ( ?is bell are gov]n$ by ^? ( ! o!r4 ,sets ( bells prop]ly tun$ are (t5 scatt]$ ab\t & controll$ f a keybo>d4 ,!re are usually eighte5 bells 9 su* a set4 ,bl9d+ ,lights4--,9 c]ta9 acts x is necess>y = ! actor to "w "p ( ! "t unse5 by ! audi5ce4 ,?is may easily be arrang$ = by ! use ( a numb] ( bright lights plac$ betwe5 him & ! audi5ce4 ,^! lights1 :5 burn+1 bl9d ! audi5ce s t !y _c see beyond !m4 ,! lamps mu/ be plac$ 9 reflectors :i* ?r[ all light t[>d ! audi5ce4 ,!y are arrang$ ei!r ^u ! floor ( ! /age or ar\nd cab9ets or o!r devices4 ,! bl9d+ effect dep5ds ^u ! contra/ betwe5 ! front & ! re> ( ! lamps4 ,lights %\ld be v bright b ! quantity ( light mu/ n be suffici5t to cause reflect$ light f ! front to illum9ate ! back ( ! /age4 ,:]e em]g5cy lights are kept burn+ dur+ ! p]=mance x is q difficult to c>ry out ! bl9d+ effect = any consid]able l5g? ( "t4 ,brackets4--,brackets are made up 9 any ( ! ?ree ways %[n 9 ,figure #ahg4 ,if ! /em is l>ge en\gh to admit ! cable1 :i* %\ld be us$ to ! p9-plug connector1 no splice ( any k9d w be necess>y4 ,if ! bracket /em is too small = ?is1 fixture wire mu/ be us$ & a connection f x to ! cable mu/ be made4 ,if ?is is made1 z at ! extreme "r1 ! back ( ! canopy mu/ be enclos$ 9 sub/antial metal4 ,on no acc\nt %\ld fixture wire be all[$ to ext5d outside ( ! /em4 ,! bracket mu/ h "s provision by :i* x c be made to hold its prop] position :5 9 place4 ,sometimes hooks are provid$ = ?is purpose & at o!r times x is held 9 place by screws 9 ! sc5]y1 z sugge/$ by ! back ( ! canopy %[n at ,a4 ,national ,electrical ,code ,rule = ,lights on ,sc5]y4 ,:]e brackets are us$ !y mu/ be wir$ entirely on ! inside2 fixture /em mu/ come ?r\gh to ! back ( ! sc5]y & end ( /em be prop]ly bu%$4 ,illu/ration3 ,,figure #ahg4 ,bun* ,lights4--,bun* lights are made up accord+ to ! plans %[n 9 ,figure #ahh4 ,!y are us$ only on ! /age4 ,no v brilliant illum9ation c be obta9$ f !m4 ,9 "o well-kn[n production a bun* light conta9+ "o hundr$ #cb c4-p4 lamps 0 us$ )\t obta9+ ! result desir$4 ,! light _c be conc5trat$ z c t f arc lamps4 ,bun* lights1 h[ev]1 h ! advantage ( n requir+ s mu* att5tion z arc lamps & c (t5 be us$ on a %all[ /age :]e arc lamps w\ld be out ( place4 ,bun* lights are sometimes made d\ble1 two on "o /&2 two colors c ?us be us$ at ! same "t & c]ta9 color *anges facilitat$4 ,color effects or *anges 9 colors are br\ght ab\t by ins]t+ color$ gelat9e slides 9 front ( ! lights4 ,national ,electrical ,code ,rules = ,bun* ,lights4 ,mu/ be sub/antially con/ruct$ ( metal & mu/ n conta9 any expos$ wir+4 ,illu/ration3 ,,figure #ahh4 ,! cable1 fe$+ same1 mu/ be bu%$ 9 an approv$ mann] :]e pass+ ?r\gh ! metal1 & mu/ be prop]ly secur$ to prev5t any me*anical /ra9 on ! connection4 ,*&eli]s4--,! rule :i* requires all wir+ ab\t brackets to be enclos$1 naturally w\ld apply "h also4 ,9 connection ) *a9 fixtures1 :i* are at pres5t v popul>1 ?is requirem5t is g5]ally ov]look$ if good re9=c$ cord is us$4 ,ord9>y fixture wire or flexible cord %\ld n be us$4 ,! weake/ "p ( a *a9 fixture is indicat$ 9 ,figure #ahi by ! arr[4 ,! op5+ at ?is place is1 z a rule1 too small & n well ream$ out4 ,fixtures us$ on ! road are con/antly giv+ way at ?is po9t4 ,! op5+ %\ld be l>ge en\gh to pass re9=c$ cord & %\ld be well ream$ out4 ,if ! op5+ _c be made l>ge en\gh to give ! wire a little free movem5t1 x is advisable to wrap tape ar\nd ! wire & ! metal 9 su* a way z to prev5t all motion ( ! wire at ?is po9t4 ,! same obs]vations also apply to ! o!r end :]e ! cord ent]s ! socket4 ,illu/ration3 ,,figure #ahi4 ,illu/ration3 ,,figure #aij4 ,illu/ration3 ,,figure #aia4 ,ano!r frequ5t s\rce ( tr\ble ) *&eli]s is f\nd at ! end ( ! /em :]e connection is made to ! cable :i* fe$s ! fixture4 ,see ,figure #aij4 ,v (t5 fixture wire is br\ght out "h1 b ?is w soon break4 ,! /age cable1 or re9=c$ cord1 %\ld be run d[n to ! bottom ( ! fixture & connections !re made to ! wires lead+ to ! v>i\s arms4 ,!re are _m fixture hooks made up aft] ! mann] %[n 9 ,figure #aia :i* h a small op5+ = ! wire at ! po9t indicat$ by ! arr[4 ,?is op5+ is always too small & 9 su* a case x is be/ to arrange a tee z %[n4 ,a *&eli] mu/ always be hung 9 su* a mann] z to avoid /ra9 com+ on ! electrical conductors4 ,illu/ration3 ,,figure #aib4 ,colors4--,:]e a c]ta9 color is want$1 dur+ ! :ole %[1 f a c]ta9 light s\rce1 ! inc&esc5t lamps !mselves may be color$4 ,prep>$ colors = ?is purpose are on ! m>ket & x is be/ to use !m4 ,:]e ! colors 9 a sc5e *ange rapidly !re mu/ be "s color$ mat]ial available :i* c be quickly int]pos$ betwe5 ! light & ! sc5e4 ,! mann] 9 :i* ?is is done = bun* lights is indicat$ 9 ,figure #ahh4 ,! same me?od is also us$ 9 connection ) op5-arc lamps1 b = spot lights !re is ano!r me?od1 %[n 9 ,figure #aib4 ,?is is a s-call$ color :eel & ! colors c be *ang$ by simply revolv+ ! :eel until ! prop] color is 9 front ( ! l5s4 ,an automatic color :eel is on ! m>ket :i* all[s ! op]ator to control colors at a di/ance by means ( an electric circuit & magnet4 ,?is device _c be us$ ) flood lamps & has ! fur!r disadvantage ( ca/+ unavoidable %ad[s dur+ ! *ange ( colors4 ,:]e deta*able color hold]s are us$1 x is possible to *ange f "o color to ano!r by almo/ imp]ceptible degrees by hold+ ! frame 9 ! h& & br++ x gradually f a di/ance to ! front ( ! lamp4 ,9 ?is mann] ! %ad[s ca/ by ! frame c be avoid$ & ! color br\ght v gradually into ! sc5e4 ,illu/ration3 ,,figure #aic4 ,dimm] ,box4--,! dimm] box1 z ! "n implies is a box :i* conta9s ! resi/ances requir$ = dimm+ lights us$ on ! /age4 ,x comes into s]vice only ) ! m pret5ti\s %[s :i* c>ry foot-lights or bord]-lights4 ,a typical wir+ diagram is %[n 9 ,figure #aic4 ,?is diagram supposes t n m ?an ?ree colors are us$4 ,a small c&le p[] inc&esc5t lamp %\ld always be in/all$ 9 ! box s t ! op]ator may see :at is necess>y 9 d>k sc5es4 ,?is lamp %\ld h its own fuse protection4 ,?is is a po9t v (t5 ov]look$ by op]ators4 ,! box is usually made ( wood & l9$ ) metal4 ,x %\ld be deep & ne>ly squ>e1 s z to occupy a m9imum ( space4 ,if a %all[ box is us$1 x w be necess>y to place ! swit*es 9 a sep>ate comp>tm5t f ! fuses1 s t ! latt] may be always enclos$1 ev5 :ile ! dimm]s & fuses are be+ op]at$4 ,illu/ration3 ,,figure #aid4 ,provisions %\ld be made = ! cables to lead out ?r\gh suitable bu%+s at ! side in/ead ( ov] ! top ( ! box z is s (t5 done4 ,9 "s dimm] boxes ! slip connectors are fitt$ into ! side ( a box s t ! male end may be ins]t$ f outside4 ,?is makes x unnecess>y to bu% ! cables ?r\gh ! box4 ,electric ,sign ,imitations4--,^! are us$ mo/ly 9 repres5tations ( city night sc5es4 ,a fla%] sign c be imitat$ by cutt+ small r\nd holes 9 ! curta9 to outl9e ! read+ matt] on ! sign4 ,beh9d ^! holes a moon box is plac$1 ! lamps 9 x be+ on a fla%] or controll$ by 8ske$oodle0 sockets1 ?us giv+ ! effect ( an electric sign on a fla%]4 ,9 case ! effect ( a /eady burn+ sign is want$ ! fla%] is omitt$4 ,electric signs imitat+ fall+ wat] h 9 turn be5 imitat$ accord+ to ! plan outl9$ 9 ,figure #aid4 ,on ! side ne>e/ ! audi5ce is ! curta9 ,a1 ^u :i* ! sign is pa9t$ & 9 :i* !re are a numb] ( holes repres5t+ ! electric lamps 9 ! orig9al sign2 beh9d ?is curta9 is a grat+ ,b1 also full ( holes2 & beh9d ?is revolves a spiral ,c1 s arrang$ z to ob/ruct int]mitt5tly ! light :i* is beh9d x4 ,! object is to imitate1 z ne>ly z possible1 ! action ( ! lights 9 ! orig9al sign4 ,electric ,/age ,effects4--,a l>ge numb] ( /age effects c be produc$ by prop]ly pa9t$ mica discs :i* are caus$ to move 9 front ( ! l5s ( a spot light arrang$ = ! purpose4 ,a view ( su* a contrivance is giv5 9 ,figure #ahb & is kn[n z ! 8,sciopticon04 ,! effects are *ang$ by clockwork :i* is adju/able z to spe$4 ,! device is arrang$ to slip 9 front ( ! l5ses & c be atta*$ 9 a mom5t4 ,a li/ ( "s ( ! effects obta9able is giv5 bel[3 ,avalan*e ,climb+ monkeys ,cyclone ) fly+ objects ,fall+ leaves ,fireworks ,flame ,fl[+ wat] ,fly+ birds ,lightn+ ,mov+ cl\ds ,niag>a ,falls ,ocean waves ,ra9b[ ,ra9 ,ris+ fire & smoke ,roll+ lava ,s& /orm ,sn[ /orm ,swimm+ fi% ,tw9kl+ />s ,volcano ,wat] falls ,! above li/ is giv5 to illu/rate ! possibilities ( ?is me?od ( produc+ effects4 ,!y are1 h[ev]1 r exp5sive & "s ( !m require sev]al ma*9es to be 9 op]ation at ! same "t4 ,explosions4--,ne>ly all explosions are set (f by ! melt+ ( a fuse ?r\gh an electrical %ort circuit4 ,! explosive p[d] is plac$ above1 encloses ! fuse1 & is ignit$ :5 ! fuse bl[s4 ,illu/ration3 ,,figure #aie4 ,su* explosions are (t5 =bidd5 by inspectors b !re is no dang] f !m if ! p[d]1 etc41 is enclos$ 9 a suitable wire me% op5 on all sides4 ,?is w n int]f]e ) ! explosion & w prev5t ! flame1 :i* la/s b an in/ant1 f com+ 9 contact ) sc5]y or p4 ,:]e su* explosions are us$ !y are g5]ally ! mo/ important "p ( ! act1 & e possible precaution mu/ be tak5 to avoid ! *ance ( failure4 ,!y are1 !re=e1 (t5 arrang$ on two circuits ) a ?r[-ov] swit* s t 9 case "o fuse fails ! circuit c be imm$iately clos$ on ! o!r4 ,see ,figure #aie4 ,x requires "s "t to ?r[-ov] a swit*1 & 9 ord] to make d\bly sure t ! fuse w bl[ at ! "r "t1 two fuses & two sep>ate wires may be us$ & connect$ at ! same "t by a simple d\ble-pole swit*4 ,! latt] arrangem5t has ! disadvantage t "o ( ! wires might be brok51 or ! contacts bad1 )\t ! defect ev] be+ notic$ until ! o!r wire also fails & ! explosion misses entirely4 ,x is be/ to use ! ?r[-ov] swit* & to use ! wires = ! fir/ connection 9 alt]nation s t a defect may be notic$ at once4 ,if ! same wire 7 us$ ea* "t ! ?r[-ov] swit* w\ld be op5 to ! same objection z ! d\ble-pole swit*4 ,9 select+ fuses = ?is "w x mu/ be borne 9 m9d t ! p[d] :i* is plac$ ov] ! fuse has a c]ta9 cool+ & conduct+ effect1 & t (t51 !re=e1 a fuse :i* w\ld readily bl[ if 9 ! op5 w\ld n bl[ if cov]$ ) metallic p[d]4 ,face-,o-,graph4--,?is is an arrangem5t ( two p[]ful arc lamps ) ! necess>y l5ses & objective by :i* ! face ( an actor c be project$ ^u a scre54 ,?is effect is v try+ to ! face & eyes ( ! actor4 ,! face mu/ be br\ght v close to ! arc lamps & mu/ be held upside d[n dur+ ! p]=mance4 ,f =ty to fifty amp]es are us$ 9 ea* arc lamp4 ,! optical pr9ciple is expla9$ 9 ano!r *apt]4 ,fe/oons4--,fe/oons %\ld be made up z %[n 9 ,figure #aif4 ,wea!rpro( sockets are g5]ally us$ because ! common brass %ell sockets h too _m p>ts t are liable to "w loose on acc\nt ( ! con/ant h&l+ ! fe/oons are subject$ to ) travel+ productions4 ,! use ( porcela9 sockets1 h[ev]1 %\ld be avoid$2 mica sockets seem to be g5]ally pref]r$4 ,! sold]+ also %\ld be c>efully done & only at ! end1 z indicat$ by ! arr[ 9 ! cut4 ,! bran* wires are (t5 tap$ to ! ma9 cable z indicat$1 b (t5 also1 circul> loom is slipp$ ov] ! cable 9 su* a mann] t ! bran* wires are support$ by x4 ,%ort l5g?s ( loom mu/ be slipp$ on ! cable be=e ! tapes are made4 ,a really well made fe/oon w la/ a long "t & give v little tr\ble2 :ile a poorly made "o w cause mu* annoyance & mu* unfavorable comm5t f inspectors4 ,mo/ ( ! fe/oon tr\bles are due to poor support ( ! bran* wires4 ,a s+le fe/oon does n (t5 c>ry m ?an t5 or twelve lights & usually n m ?an six or eight4 ,illu/ration3 ,,figure #aif4 ,a c]ta9 /yle ( %ade is v mu* 9 vogue 9 connection ) fe/oon lamps & ?is %ade makes ! use ( lamp gu>ds impossible4 ,if ! %ade is made ( gelat9e !re w be b little ne$ = ! gu>d1 b celluloid %ades %\ld n be all[$4 ,all combu/ible mat]ial t is to come ne> ! lamp or ! socket %\ld be firepro($4 ,! ,national ,electrical ,code ,rule = ,/r+ or ,fe/oon$ ,lights4 ,wir+ ( same mu/ be ( approv$ type2 jo9ts to be prop]ly made1 sold]$1 & tap$1 & /agg]$ :]e practicable4 ,:]e lamps are us$ 9 lant]ns or simil> devices1 approv$ gu>ds mu/ be employ$4 ,fire ,dance4--,?is effect is g5]ally illum9at$ f bel[ ! /age1 ! light be+ ?r[n upw>d ?r\gh glass4 ,special arc lamps1 equipp$ ) p[]ful reflectors1 are (t5 us$ & g5]ally sev]al ( !m are requir$ to produce ! prop] effect4 ,if spot lamps are to be us$ !y %\ld n be turn$ upw>d b in/ead reflectors plac$ at an angle ( =ty-five degrees1 %\ld be provid$ to ?r[ ! light upw>d4 ,see ,figure #aig4 ,if a spot lamp is turn$ upw>d1 ! heat ( ! arc ris+ w be great en\gh to make cond5s] breakage a v s]i\s problem4 ,x is also difficult to keep a horizontal arc work+ prop]ly4 ,illu/ration3 ,,figure #aig4 ,fireflies4--,! 8fireflies0 are m9iature inc&esc5t lamps /rung ab\t among ! sc5]y & on ! clo?+ or 9 ! hair ( p]=m]s4 ,no attempt %\ld be made to op]ate ^! f any o!r s\rce ?an a l[-voltage1 l[-amp]age batt]y4 ,x is be/ to subdivide !m z mu* z possible to avoid %ort circuits4 ,a %ort circuit on "o lamp w\ld put out a gr\p ( "o hundr$ z quickly z x w\ld t54 ,su* lamps are (t5 arrang$ on a keybo>d by :i* s+le lamps or small gr\ps may be light$ int]mitt5tly1 ?us giv+ ! effect ( fireflies flitt+ ab\t4 ,fireplaces4--,! commone/ & be/ fireplace is made up ( a few lights arrang$ 9 regul> /rip fa%ion1 ! /rip be+ plac$ 9 a practical fireplace fill$ ) coal or l>ge pieces ( glass1 su* z brok5 pieces ( l5ses4 ,= a v simple effect1 r$ color$ globes are us$4 ,! effect c be enhanc$ by us+ lamps ( amb]1 r$1 & :ite & connect+ ea* lamp to a dimm] :i* c be work$ (f ! /age4 ,?is is capable ( produc+ a flam+ effect4 ,a fur!r enhancem5t ( ! effect is sometimes produc$ by plac+ color$ asbe/os ab\t ! lights4 ,?is or o!r suitable mat]ial c be made to repres5t gl[+ a%es v nicely4 ,v (t5 ! illum9ation ( ! fireplace is by means ( color$ globes /rung ab\t among ! logs4 ,= ?is purpose !y mu/ be equipp$ ) /rong gu>ds & wir$ ) /age cable4 ,actual gas flames are also (t5 mix$ 9 ) ! electric illum9ation4 ,9 a me*anical way ! effect ( flame is (t5 imitat$ by color$ clo? s arrang$ t a small fan motor plac$ b5ea? x c bl[ x upw>d4 ,9 a c]ta9 well-kn[n production1 an imitation ( ! crat] ( a volcano is made by arrang+ a numb] ( fan motors "u a l>ge piece ( silk :i* re/s ^u a frame & revolves ov] ! motors4 ,p>ts ( ?is silk are provid$ ) pockets & are loose s t !y may be bl[n upw>d to repres5t flame :ile ! major portion only undulates1 repres5t+ a sea ( molt5 lava4 ,/rips ) r$ lights are us$ to int5sify ! effect4 ,a small motor op]at+ a suitable rat*et has be5 us$ to imitate ! s\nds ( wood crackl+ 9 ! fire4 8,*emical smoke0 is also (t5 us$ to enhance ! effect4 ,?is c be pur*as$ ( supply h\ses4 ,flat ,irons4--,see 8,heat]s04 ,fl[]s4--,on ! vaudeville /age1 electrically light$ fl[]s are sometimes us$4 ,^! are (t5 wir$ by simply runn+ fixture wire or flexible cord along a wire /em & fa/5+ a small socket to x4 ,fl[]s light$ 9 ?is mann]1 h[ev]1 w n be all[$ 9 !at]s :]e !re is inspection4 ,a bett] me?od is %[n 9 ,figure #aih4 ,armor$ cord is us$ = ! /em & a m9iature socket is plac$ at ! end4 ,all splices are )9 ! junction box :i* supports ! /ems4 ,in/ead ( ! armor$ cord ord9>y fixture tub+ may be us$4 ,baskets ( fl[]s & small b\quets are g5]ally light$ f batt]ies4 ,illu/ration3 ,,figure #aih4 ,f\nta9s4--,! illum9ation = electrically light$ f\nta9s is sometimes obta9$ f inc&esc5t lamps1 b no v %[y effects c be produc$ ) !m4 ,:]e !y are us$ 9 a mann] :i* subjects !m to moi/ure !y mu/ be wir$ 9 wat]pro( conduit & fitt+s & ! lamps mu/ be cov]$ by a wat]tight globe4 ,= brilliant effects arc-lamp illum9ation is necess>y & ! arc mu/ ( c\rse be bel[ ! wat]4 ,z arc lamps :5 tilt$ upw>d break cond5s]s v rapidly1 ! light is usually reflect$ upw>d by means ( mirrors set z indicat$ 9 ,figure #aig4 ,fuses4--,!re is no "p ( ! electrical equipm5t ( a travel+ production s mu* abus$ z ! fuse4 ,x is provid$ prim>ily = ! protection ( app>atus & %\ld nev] be ( great] capacity ?an is ne$$ to c>ry ! load put ^u x4 ,!re is no?+ :atev] ga9$ by ! use ( l>g] fuses4 ,if ! load is n 9 excess ( six amp]es1 a six amp]e fuse w c>ry x z readily z a tw5ty amp]e fuse4 ,if a %ort circuit occurs ! tw5ty amp]e fuse w bl[ z readily z ! six amp]e fuse &1 9 addition1 w cause de/ruction ( a socket or :atev] may be ! cause ( ! tr\ble z well z an increas$ fire haz>d4 ,not)/&+ ! above1 x is a r>e exception :5 "o f9ds ! circuits ( a travel+ outfit prop]ly fus$4 ,= ?is !re are two reasons4 ,"o is t1 ow+ to frequ5t h&l+ & mov+1 fuses "w loose2 & ?us1 to ! natural heat produc$ by ! load1 !re is add$ a c]ta9 am\nt ( heat produc$ 9 ! poor contacts4 ,tr\ble ( su* a nature c be less5$ by ! use ( l>g] fuses1 b only to a v small ext5t4 ,x is f> bett] to g ov] "o's fuses two or ?ree times a week & tight5 ! screws & contacts to avoid ?is tr\ble ?an to use ov]-l>ge fuses4 ,ano!r reason = ! ov]fus+1 ( plugg+ boxes especially1 is f\nd 9 ! fact t arc & inc&esc5t plugs are int]*angeable4 ,if1 !re=e1 ea* circuit is fus$ at ?irty amp]es "o ne$ n worry ab\t :i* pocket an arc lamp is connect$ to4 ,?is practice is1 h[ev]1 v bad1 a table lamp1 = in/ance1 ) a ?irty-amp]e fuse beh9d x w\ld be likely to cause fla% & smoke en\gh to al>m an audi5ce4 ,"s provisions %\ld be made s t "o c easily di/+ui% betwe5 arc & inc&esc5t pockets or divisions 9 plugg+ boxes4 ,! ma9 requisite :i* det]m9es ! /yle ( fuse to be in/all$ = /age effects is t ( quick r5ewal 9 case ( bl[-out4 ,illu/ration3 ,,figure #aii4 ,gas ,globes4--,electric light is s conv5i5t on ! /age t ev5 gas light is imitat$ by x4 ,9 "o production 9 :i* x 0 desirable to %[ ! front ( a !at] illum9at$ by gas1 ! gas globes 7 made up ( clo? cut z %[n 9 ,figure #aii4 ,beh9d ea* imitation globe a small inc&esc5t lamp 0 arrang$4 ,glass ,%ades4--,an imitation ( ^! = small desk or table lamps is (t5 made by plac+ a /rip ( color$ gelat9e betwe5 two lay]s ( wire me%4 ,! wire scre5 keeps ! gelat9e /raight & ! :ole is m s]viceable ?an glass & less liable to break4 ,heat]s4--,"u ?is head come flatirons & wat] heat]s4 ,flatirons are c>ri$ by _m actors :o cause mu* tr\ble by connect+ !m to light+ circuits4 ,9 _m places ! h\se electrician prev5ts _! use by fus+ 8 light+ circuits s l[ t ! addition ( a flatiron imm$iately bl[s ! fuse4 ,if us$ at all1 ! flatirons %\ld be ( ! small] k9d4 ,small heat]s are also ext5sively us$ ^u ! /age4 ,national ,electrical ,code ,rule = ,electric ,heat]s4 ,x is (t5 desirable to connect 9 multiple ) ! heat]s & betwe5 ! heat] & ! swit* controll+ ! same1 an inc&esc5t lamp ( l[-c&le p[]1 z ?is %[s at a glance :e!r or n ! swit* is op51 & t5ds to prev5t its be+ left clos$ ?r\gh ov]sight4 ,mu/ be protect$ by a cut-out & controll$ by indicat+ swit*es4 ,swit*es mu/ be d\ble-pole except :5 ! device controll$ does n require m ?an #ffj watts ( en]gy4 ,mu/ nev] be conceal$2 b mu/ at all times be 9 pla9 sight4 ,special p]mission may be giv5 9 writ+1 by ! ,inspection ,dep>tm5t hav+ jurisdiction1 = dep>ture f ?is rule4 ,flexible conductors = smoo?+ irons & sadirons & = all devices requir+ ov] #bej watts mu/ h an approv$ insulation & cov]+4 ,= portable heat+ devices ! flexible conductors mu/ be connect$ to an approv$ plug device1 s arrang$ t ! plug w pull out & op5 ! circuit 9 case any abnormal /ra9 is put ^u ! flexible conductor4 ,?is device may be /ation>y1 or x may be plac$ 9 ! cord itself4 ,! cable or cord mu/ be atta*$ to ! heat+ app>atus 9 su* a mann] t x w be protect$ f k9k+1 *af+1 or l injury at or ne> ! po9t ( connection4 ,smoo?+ irons1 sadirons1 & o!r heat+ appliances t are int5d$ to be appli$ to inflammable articles1 su* z clo?+1 mu/ con=m to ! above rules s f> z !y apply4 ,!y mu/ also be provid$ ) an approv$ /&1 on :i* !y %\ld be plac$ :5 n 9 use4 ,/ation>y electric heat+ app>atus1 su* z radiators1 ranges1 plate w>m]s1 etc41 mu/ be plac$ 9 a safe location1 isolat$ f inflammable mat]ials1 & be treat$ z s\rces ( heat4 ,devices ( ?is description w (t5 require a suitable heat-resi/+ mat]ial plac$ betwe5 ! device & its surr\nd+s4 ,su* protection may be/ be secur$ by in/all+ two or m plates ( t9 or %eet /eel ) a "o-in* air space betwe5 or by alt]nate lay]s ( %eet /eel & asbe/os ) a simil> air space4 ,mu/ ea* be provid$ ) "n-plate1 giv+ ! mak]'s "n & ! normal capacity 9 volts & amp]es4 ,ligh?\se ,effect4--,to increase ! effect ( a ligh?\se pa9t$ ^u ! sc5]y1 a /rip ( suitable l5g? ) "o light at ea* end is provid$4 ,! /rip circuit conta9s a fla%] s t bo? lights are turn$ on & (f at regul> int]vals4 ,"o lamp mu/ be beh9d ! head ( ! ligh?\se1 ! o!r :]e ! reflection ( ! upp] light w\ld appe> 9 ! wat]4 ,lightn+4--,! /&>d me?od ( produc+ lightn+ effects ^u ! /age is by means ( ! device %[n 9 ,figure #bjj4 ,a magnet & ! arc-/rik+ c>bons are arrang$ 9 s]ies & take curr5t ?r\gh a resi/ance4 ,normally ! c>bons are 9 contact & :5 ! swit* is clos$ ! curr5t passes ?r\gh ! magnet & c>bons4 ,! curr5t en]gizes ! magnet & causes ! upp] c>bon to sep>ate f ! l[]1 ?us /rik+ ! arc4 ,! arrangem5t mu/ be su* t ! arc is imm$iately brok51 ?us de-en]giz+ ! magnet2 ?is all[s ! movable c>bon to close ! circuit aga91 ?us repeat+ ! op]ation4 ,?is device if un9t]rupt$ w give a rapid succession ( lightn+ effects & x may be susp5d$ 9 ! w+s z x is entirely automatic4 ,at ! "r ( ,figure #bjj is %[n ano!r lightn+ /rik] :i* is op]at$ by h&4 ,illu/ration3 ,,figure #bjj4 ,:]e x is n prohibit$1 a v good lightn+ effect c be obta9$ by arrang+ a file & a piece ( c>bon z opposite poles ( ! circuit & scrap+ !m toge!r4 ,x is a bad practice1 h[ev]1 to /rike an op5 arc on any /age4 ,!re %\ld always be wire me% ar\nd x to prev5t ! escape ( sp>ks4 ,automatic /rik]s c be pur*as$ :i* w make an op5 arc lamp produce good lightn+ effects4 ,ano!r me?od ( produc+ lightn+ is t ( fla%+ "s ( ! bord] lights4 ,?is w d 9 an em]g5cy b does n comp>e ) ! o!r me?ods4 ,sometimes ! effect ( a bolt ( lightn+ /rik+ a c]ta9 place is imitat$ by an arc slid+ swiftly d[n a wire4 ,9 ord] to /rike ! arc at ! prop] mom5t1 ! app>atus be+ some:]e up 9 ! flies1 a small fuse is connect$ f "o c>bon to ! o!r4 ,! curr5t :5 turn$ on passes ?r\gh ! fuse1 melts x1 & e/abli%es ! arc4 ,! c>bons are incas$ 9 a v small wire-me% enclosure & ! :ole device is made to slide swiftly d[n a tight wire lead+ to ! prop] place4 ,! m pret5ti\s %[s (t5 use sev]al lightn+ ma*9es to avoid ! monoton\s effect ( all lightn+ /rokes com+ f ! same direction4 ,"o resi/ance may be made to s]ve = any numb] ( lightn+ ma*9es provid$ only "o ma*9e is us$ at a "t4 ,illu/ration3 ,,figure #bja4 ,lugs4--,lugs mu/ be provid$ = all leads :]e m ?an #cj amp]es are us$4 ,x is ev5 m necess>y to foll[ ?is rule 9 connection ) portable !at] equipm5t ?an ) o!r wires because !y are m apt to "w loose4 ,= ! connections to ! arc lamp & rheo/ats x is n practicable to use sold]$ lugs because no sold] w /& ! heat4 ,two /yles ( lugs t may be us$ are %[n 9 ,figure #bja4 ,! cuts w also expla9 ! mann] ( connect+ ! lugs4 ,at ! left1 ! b>e lugs are %[n2 9 ! c5t] ! copp] ( ! conductors is %[n ins]t$ into ! lugs1 & at ! "r ! :ole conductor is %[n b5t back1 ! metal ( ! lug cat*+ ov] ! insulation to keep x f fray+ out4 ,! wires fe$+ arc lamps are always asbe/os cov]$ & ?is cov]+ fits loosely to ! wire & mu/ be held 9 "s su* mann]4 ,a /ock ( su* lugs %\ld always be c>ri$1 z ! lead+-9 wires to arc lamps1 us+ heavy curr5ts1 frequ5tly burn (f4 ,illu/ration3 ,,figure #bjb4 ,moon ,boxes4--,^! boxes are g5]ally made up z %[n at ! left 9 ,figure #bjb4 ,! op5+ is f twelve to f\rte5 in*es 9 diamet]4 ,f\r lamps give v good illum9ation4 ,! frame mu/ be provid$ ) hooks s t x may be susp5d$ at any desir$ "p ( ! sc5]y4 ,x is always hung close beh9d a curta9 & mu/ be s arrang$ t ! lamps _c t\* ! curta94 ,! wires %\ld be entirely enclos$ 9 metal ( ,no4 #bj %eet metal gauge aft] ! mann] ( /rips4 ,v *eap productions (t5 c>ry moon boxes made up ( an inc&esc5t lamp fa/5$ 9 a t9 di%1 simil> to ! "o %[n at ! "r 9 ,figure #bjb4 ,moonlight on ,wat]4--,?is & all simil> effects c be produc$ ?r\gh ! 8,sciopticon0 b ?is requires ! use ( an arc lamp & is exp5sive4 ,a *eap way ( produc+ ! effect is illu/rat$ 9 ,figure #bjc1 :i* repres5ts a metal cyl9d]1 p]=at$ z %[n1 inside ( :i* !re are a numb] ( inc&esc5t lamps color$ to suit4 ,! cyl9d] is sl[ly revolv$ & ! mov+ %ad[s & /reams ( light ?r[n ^u ! sc5e produce ! effect4 ,illu/ration3 ,,figure #bjc4 ,illu/ration3 ,,figure #bjd4 ,a some:at simil> me?od ( produc+ ?is effect1 z also t ( a wat]fall1 is illu/rat$ 9 ,figure #bjd4 ,9 ?is case a spiral capable ( be+ mov$ by clock "w is revolv$ ab\t an electric lamp & gives ! effect ( fall+ wat]4 ,bo? ( ^! devices "w beh9d curta9s4 ,musical ,acts4--,!re are num]\s musical acts ^u ! road 9 :i* ! beat ( ! music is emphasiz$ by light+ color$ lamps 9 "t ) ! tunes4 ,x is advisable to arrange all su* acts to op]ate by batt]ies4 ,9 _m places inspectors w n all[ high-voltage contacts to be us$ op51 & x is (t5 difficult to enclose !m 9 a practical mann]4 ,by us+ dry batt]ies ! app>atus is tak5 out ( ! jurisdiction ( inspectors & all dang] ( fire is also elim9at$4 ,musical ,bells4--,sets ( musical bells prop]ly tun$ & connect$ to a keybo>d f :i* !y c be op]at$ electrically are c>ri$ 9 /ock by deal]s 9 !atrical supplies4 ,sets are usually made up ( eighte5 bells & !y may be play$ f a di/ance4 ,oil ,lamps4--,^! h be5 imitat$ by arrang+ a small batt]y inside ( ! base ( ! lamp4 ,?is batt]y w\ld supply curr5t only dur+ ! %ort "t t ! lamp 0 be+ c>ri$ ab\t4 ,! base ( ! lamp is also fitt$ ) electrical contacts :i* re/ ^u simil> contacts fitt$ into ! table1 & ?r\gh :i* ! lamp is kept burn+ by a /orage batt]y :ile x is re/+ ^u ! table4 ,a small dry batt]y1 su* z is plac$ 9 ! base ( an oil lamp1 w\ld n keep ! light burn+ = a long en\gh "t4 ,p9-,plug ,connectors4--,^! are provid$ to connect cables to effects us$ on ! /age4 ,! ess5tial po9ts ( a good connector are3 ,x %\ld grip ! :ole cable1 ?us mak+ x unnecess>y to /rip ! out] braid f any expos$ "p ( ! cable2 & x %\ld (f] no live screws or contacts on ! outside4 ,^! conditions are fulfill$ by ! connector %[n 9 ,figure #bje4 ,9 "s ( ^! connectors1 h[ev]1 ! "p t grips ! cable 7indicat$ by ! arr[7 is made ( metal1 & ?is1 if =c$ d[n too tight1 may cut into ! cable & cause a %ort circuit4 ,sev]al in/ances ( ?is k9d h be5 kn[n to occur4 ,p9-plug connectors mu/ always be connect$ s t ! project+ p9s are dead :5 ! plug is disconnect$4 ,illu/ration3 ,,figure #bje4 ,illu/ration3 ,,figure #bjf4 ,a special w>n+ aga9/ ! use ( su* connectors z are illu/rat$ at ! "r ( ,figure #bje is necess>y4 ,_! *eapness br+s !m into use v (t51 especially ) acts t d n c>ry compet5t electricians4 ,! wires are always work+ loose2 project+ ends are b>e1 & if ! connector is twi/$1 a %ort circuit results4 ,:]e !y mu/ be us$ 9 an em]g5cy1 !y %\ld be heavily tap$1 ! tape be+ plac$ betwe5 ! conductors & all ar\nd ! plug1 z %[n 9 ! figure4 ,bran*-(f connectors su* are %[n 9 ,figure #bjf are (t5 us$ to tap (f lights f ! ma9 cable4 ,:]e plug connectors are us$ = arc lamps !y mu/ be made up z %[n 9 ,figure #bjg4 ,! asbe/os-cov]$ wires necess>y to be us$ ) arc lamps _c be us$ 9 cable b mu/ be sep>ately connect$4 ,illu/ration3 ,,figure #bjg4 ,! ,national ,electrical ,code ,rules = ,p9-,plug ,connectors4 ,mu/ be ( an approv$ type1 s in/all$ t ! female "p ( ! plug w be on ! live end ( ! cable1 & mu/ be s con/ruct$ t t5sion on ! cable w n cause s]i\s me*anical /ra9 on ! connections4 ,plugg+ ,boxes4--,plugg+ boxes are us$ to obviate ! necessity ( runn+ a l>ge numb] ( wires ov] ! /age to ! diff]5t /age pockets4 ,!y are also a necessity because _m !at]s are n equipp$ ) a suffici5t numb] ( /age pockets to accommodate all ( ! devices l>ge productions c>ry4 ,! plugg+ box %\ld be firepro(2 %\ld h self-clos+ doors s t !re may be no liability ( op5 fuses be+ left among ! sc5]y :]e !y are us$4 ,mo/ ( ! plugg+ boxes 9 use at ! pres5t "t are arrang$ = l9k fuses4 ,a l9k fuse1 h[ev]1 requires m "t to in/all ?an a c>tridge fuse & ! latt] w\ld !re=e seem mu* m desirable4 ,a cut ( a mu*-us$ plugg+ box is %[n 9 ,figure #bjh4 ,illu/ration3 ,,figure #bjh4 ,! ,national ,electrical ,code ,rules = ,portable ,plugg+ ,boxes4 ,mu/ be con/ruct$ s t no curr5t-c>ry+ "p w be expos$1 & ea* receptacle mu/ be protect$ by approv$ fuses m\nt$ on slate or m>ble bases & enclos$ 9 a firepro( cab9et equipp$ ) self-clos+ doors4 ,ea* receptacle mu/ be con/ruct$ to c>ry ?irty amp]es )\t undue heat+1 & ! bus-b>s mu/ h a c>ry+ capacity equival5t to ! curr5t requir$ = ! total numb] ( receptacles1 & approv$ lugs mu/ be provid$ = ! connection ( ! ma/] cable4 ,rheo/ats4--,portable /age equipm5t be+ int5d$ = use 9 all p>ts ( ! c\ntry mu/ be adju/able to all k9ds ( light+ sy/ems4 ,= ?is reason x is n practicable to use auto-trans=m]s z is commonly ! case :]e arc lamps are f$ f alt]nat+-curr5t circuits4 ,simple rheo/ats or resi/ances are !re=e always us$4 ,) ^! x is immat]ial :e!r ! curr5t be alt]nat+ or direct except 9 s f> z ! quantity is conc]n$4 ,alt]nat+ curr5t be+ less effici5t 9 ! production ( useful light ?an direct curr5t1 ! amp]age mu/ be great] & ?is produces a great] loss 9 voltage1 ! loss be+ always proportional to ! product ( curr5t times resi/ance4 ,! drop 9 voltage ov] a c]ta9 resi/ance is !re=e always great]1 :5 an alt]nat+-curr5t arc is us$1 ?an x is ) direct2 b z ! alt]nat+-curr5t arc op]ates at a l[] voltage ?an ! direct ?is is n objectionable & simple resi/ances give satisfactory results :e!r us$ ) "o k9d ( curr5t or ! o!r4 ,! travel+ %[ mu/ also be prep>$ = diff]5t voltages & a suitably arrang$ gr\p ( resi/ances is v conv5i5t 9 ?is respect4 ,figure #bji %[s a box made by ! ,*icago ,/age ,light+ ,company conta9+ a numb] ( resi/ances :i* may be connect$ 9 v>i\s ways to obta9 diff]5t results4 ,9 ,figure #baj at ,a is giv5 a diagram repres5t+ ! wire 9 a s+le section4 ,"o su* section plac$ 9 s]ies ) an arc lamp w give a c]ta9 curr5t4 ,if we connect two ( !m 9 p>allel1 z 9 ,b1 we %all obta9 n q d\ble ! curr5t1 s9ce ?is arrangem5t does n affect ! resi/ance ( ! arc :i* also influ5ces ! curr5t /r5g?4 ,if ! connections are made z 9 ,c1 we %all h b half ! curr5t obta9able by ! use ( "o section1 or ! same curr5t 9 case we are deal+ ) d\ble ! voltage4 ,if ,a is suitable = #aaj volts1 !n ,c is suitable = #bbj volts & ,d = #eej4 ,9 ,e we h ! connection :i* w\ld give u1 = #bbj volts1 ! same curr5t ,b w\ld give ) #aaj4 ,x c ?us be se5 t a gr\p ( su* resi/ances c be made to fit an arc lamp to almo/ any voltage t is likely to be met )4 ,illu/ration3 ,,figure #bji4 ,no?+ b metal & porcela9 mu/ be us$ 9 ! con/ruction ( ^! resi/ances & !y mu/ be on /&s :i* raise !m well above ! floor4 ,! connections to ! resi/ances %\ld ord9>ily be made ) asbe/os cable4 ,x is necess>y to keep close wat* ( ! wire us$ to make up ! resi/ance especially if x becomes v hot dur+ a run4 ,a resi/ance 9 :i* ! wire becomes r$ hot %\ld n be us$4 ,!re are productions 9 :i* x is necess>y to place ! arc lamps & _! rheo/ats directly 9 ! way ( fly+ pap] us$ to make 8sn[04 ,9 su* cases ! resi/ances mu/ be tightly enclos$4 ,?is de/roys ! v5tilation & !y w readily become ov]heat$4 ,= use ) su* productions resi/ances may be specially w\nd & arrang$1 or !y may be made sep>ate f ! arc & plac$ 9 a safe location4 ,illu/ration3 ,,figure #baj4 ,/age ,cables4--,/age cables are subject to v r\gh usage1 b !re are "s v good makes on ! m>ket1 & by pur*as+ ! be/1 "o c expect long s]vice4 ,cuts ( v>i\s k9ds ( cable likely to be us$ ^u ! /age are giv5 9 ,figure #baa4 ,a is ! ord9>y /age cable2 ,b is us$ = heat]s2 ,c is re9=c$ cord2 & ,d is ! p>allel cord4 ,! la/ two mu/ n be us$ on ! floor4 ,! size ( ! wire to be us$ dep5ds ^u ! app>atus :i* ! cable mu/ supply & c be det]m9$ f ,table ,,vii :i* gives ! c>ry+ capacities4 ,only approv$ cables %\ld be us$4 ,illu/ration3 ,,figure #baa4 ,/rips4--,/rips are us$ = ! illum9ation ( special p>ts ( ! sc5]y4 ,!y usually conta9 f "o to twelve lights4 ,a /rip is subject to r\gh usage & %\ld be /rongly made4 ,cuts ( sev]al k9ds ( /rips are giv5 9 ,figure #bab4 ,! *ief tr\ble ) /rips is f\nd to be 9 ! work+ loose ( screws :i* hold ! sockets 9 place1 & ! connection at ! po9t at :i* ! cable leaves ! /rip4 ,! ,national ,electrical ,code ,rules = ,/rips4 ,mu/ be con/ruct$ ( /eel ( a ?ickness n less ?an ,no4 #bj ,u4 ,s4 %eet metal gauge1 treat$ to prev5t oxidation1 & suitably /ay$ & support$ & s design$ t flanges w protect ! lamps4 ,illu/ration3 ,,figure #bab4 ,cables mu/ be bu%$ 9 a suitable mann] :]e pass+ ?r\gh ! metal1 & mu/ be prop]ly secur$ to prev5t s]i\s me*anical /ra9 on ! connections4 ,mu/ be wir$ 9 approv$ conduit or armor$ cable1 ea* lamp receptacle be+ enclos$ )9 an approv$ outlet box1 or ! lamp receptacles may be m\nt$ 9 an iron or /eel box1 metal to be ( a ?ickness n less ?an ,no4 #bj ,u4 ,s4 %eet metal gauge1 treat$ to prev5t oxidation1 s con/ruct$ z to enclose all wires4 ,wires to be sold]$ to lugs ( receptacles4 ,illu/ration3 ,,fig4 #bac4 ,sunrise4--,sunrise effects may be produc$ by means ( ! ,sciopticon1 b a *eap] me?od is (t5 resort$ to4 ,?is is illu/rat$ 9 ,figure #bac & consi/s ( a roll ( suitably color$ silk :i* may be unroll$ 9 front ( an arc lamp4 ,to produce sunrise x is unroll$ 9 "o direction1 ! d>ke/ colors com+ fir/ & gradually giv+ way to light]4 ,= sunset x is work$ ! o!r way4 ,9 special cases a simil> %eet ( color$ silk wide en\gh to cov] op5 arcs has be5 /ret*$ f ! floor to ! top ( ! sc5]y & sev]al arc lamps arrang$ beh9d x 9 su* a mann] t !y c\ld be gradually rais$1 ?us produc+ ! same effect ) m impressiv5ess1 b ) a mu* great] quantity ( light4 ,illu/ration3 ,,figure #bad4 ,illu/ration3 ,,figure #bae4 ,swit*es4--,knife swit*es on ! /age are g5]ally requir$ to be enclos$4 ,x is n suffici5t to provide a box ) a cov] t c be clos$1 b ! swit* %\ld be 9 a box :i* ne$ n be op5$ to op]ate ! swit*4 ,see ,figure #bad4 ,(t5 x is necess>y to in/all swit*es 9 a l5g? ( /age cable s t ! swit* may be portable4 ,su* swit*es %\ld be in/all$ z %[n 9 ,figure #bae1 9 :i* a flu% swit* is %[n 9 a regul> metal enclosure4 ,illu/ration3 ,,figure #baf4 ,table ,lamps4--,! table lamp is a small device1 b x causes a great deal ( annoyance & tr\ble4 ,! bottom ( ! lamp %\ld be enclos$ ) metal1 especially if !re are any splices4 ,! /em :]e ! wire ent]s %\ld be well ream$ out 7see ! arr[ 9 ,figure #baf7 & !re %\ld be a /rong well-fa/5$ bu%+ :]e ! wire leaves ! lamp4 ,! h>d-rubb] bu%+s :i* come ) ! common table lamps d n rema9 9 place v long & are frequ5tly brok5 or lo/4 ,/age cable is g5]ally requir$ ^u ! /age1 b x is cu/om>y1 9 connection ) ^! lamps1 to all[ a good grade ( re9=c$ cord or ev5 f9e silk-cov]$ cord1 provid$ x is n long en\gh to trail on ! floor :]e x might be /epp$ ^u4 ,! glass %ades :i* are (t5 call$ = 9 connection ) ! lamps also cause mu* tr\ble2 & to avoid ?is tr\ble1 color$ gelat9e has be5 us$1 back$ up ) f9e wire scre5 to keep x 9 place4 ,?is ( c\rse _c always be done because _m lamps are n suit$ to x4 ,"t ,beat]s4--,?is is a small keybo>d locat$ at ! or*e/ra lead]'s /&2 x controls ! light :i* may be back ( ! /age & indicates ! "t to ! *orus beh9d sc5es4 ,wat] ,falls4--,! devices %[n 9 ,figure #bjd = use z moonlight on ! wat] c also be us$ to produce ! effect ( a wat]fall or ( wat] rippl+ d[n/ream4 ,,*apt] ,,xx4 ,,useful ,,facts ,,& ,,=mulas4 ,"o turn ( ! crank runs (f #a foot ( film4 ,"o foot ( film conta9s #af pictures4 ,! audi5ce sees ab\t #ifj diff]5t pictures 9 e m9ute t a film is be+ run4 ,! relative numb] ( revolutions made by two pulleys connect$ toge!r by belt+ or friction is 9 proportion to _! diamet]s4 ,! relative numb] ( revolutions made by two ge>s connect$ toge!r is 9 proportion to _! numb] ( tee?4 ,a !at] seat occupies f #d to #e squ>e feet4 ,"o #be-watt tung/5 lamp or its equival5t provid$ = e #bj seats w give fairly good illum9ation 9 a small !at]4 #c to #e watts p] cubic foot w be requir$ to heat small spaces by electricity4 ,ohm's ,law4 ,direct curr5t equals e4m4f4 divid$ by resi/ance4 ,alt]nat+ curr5t equals e4m4f4 divid$ by imp$ance4 ,electromotive =ce1 d4c41 equals curr5t "t resi/ance4 ,electromotive =ce1 a4c41 equals curr5t "t imp$ance4 ,resi/ance equals e4m4f4 divid$ by curr5t4 ,imp$ance equals e4m4f4 divid$ by curr5t4 ,! jo9t resi/ance ( two conductors connect$ 9 p>allel is equal to ! product ( _! resi/ances divid$ by _! sum3 r 7r r7 7r r7 ,! jo9t resi/ance ( any numb] ( resi/ances connect$ 9 p>allel is ! reciprocal ( ! sum ( ! reciprocals4 ,! reciprocal ( a numb] is #a divid$ by t numb]3 #a r -------------------------- #a #a #a ---- ---- ---- 44444 r r r ,! total resi/ance ( a numb] ( resi/ances 9 s]ies is equal to ! sum ( all ( !m3 r r r r 44444 ,! heat+ ( a rheo/at is proportional to ! squ>e ( ! curr5t x c>ries4 ,drop 9 voltage is proportional to ! product ( ! curr5t & resi/ance = a direct-curr5t circuit1 & ! product ( curr5t & imp$ance = an alt]nat+-curr5t circuit4 ,if a reactance is us$ 9 place ( a rheo/at 9 an alt]nat+-curr5t circuit1 ! loss ( en]gy is greatly r$uc$4 ,if ! same int5sity ( illum9ation is to be provid$ = pictures ( diff]5t sizes1 ! amp]age mu/ v>y ab\t z3 7,w #a4b7 :]e ,w is ! wid? ( picture on scre54 ,= a giv5 p[] ! curr5t 9 conductors is3 ,w = direct curr5t ,i --- ,e ,w = s+le-phase a4c4 ,i ------------- ,e p4 f4 ,w = two-phase a4c4 ,i 4#e ------------- ,e p4 f4 ,w = ?ree-phase a4c4 ,i 4#eh ------------- ,e p4 f4 9 :i* ,i is ! curr5t 9 amp]es1 ,w is ! watts1 ,e is ! voltage1 & p4 f4 is ! p[] factor4 ,l5s ,=mulas4 ,to f9d ! size ( a picture obta9able "u giv5 conditions & l5s3 ,multiply di/ance f c5t] ( l5s to scre5 by "o dim5sion ( slide or film & divide by e4f4 focal l5g? ( l5s1 tak+ all measurem5ts 9 in*es4 ,example3 ,slide #b-c_/d in*es4 ,l5g? ( ?r[ #cfj in*es4 e4 f4 #aj in*es #b-c_/d #cfj #aj #ii in*es4 ,to f9d focal l5g? ne$$ = a giv5 slide or film to produce a giv5 size ( picture3 ,multiply slide or film dim5sion by l5g? ( ?r[ & divide by dim5sion ( picture1 tak+ all measurem5ts 9 in*es4 ,example3 ,same dim5sions z above3 #b-c_/d #cfj #ii #aj in*es4 ,to f9d l5g? ( ?r[ ne$$ to obta9 a c]ta9 size ( picture3 ,multiply requir$ picture dim5sion by focal l5g? ( l5s & divide by slide or film dim5sion4 ,example3 ,same dim5sions z above3 #ii #aj #b-c_/d #cfj in*es4 ,to f9d slide size necess>y to produce a c]ta9 size ( picture "u fix$ conditions3 ,multiply focal l5g? ( l5s by size ( picture & divide by l5g? ( ?r[4 ,example3 ,same dim5sions z above3 #aj #ii #cfj #b-c_/d in*es4 ,measurem5t ( ,surfaces4 ,to f9d ! area ( a p>allelogram3 ,multiply ! base by ! altitude4 ,to f9d ! area ( a triangle :5 base & altitude are giv53 ,multiply ! base by ! altitude & take half ! product4 ,to f9d ! area ( any angul> surface3 ,divide x into triangles & f9d ! area ( ! diff]5t triangles & add !m toge!r4 ,to f9d ! circumf]5ce ( a circle3 ,multiply ! diamet] by 2 or #c4adaf4 ,to f9d ! diamet] ( a circle :5 ! circumf]5ce is giv53 ,divide ! circumf]5ce by 1 or #c4adaf4 ,to f9d ! area ( a circle :5 ! radius is giv53 ,multiply ! squ>e ( ! radius by #c4adaf4 ,:5 diamet] is giv53 ,multiply ! squ>e ( ! diamet] by 4#ghed4 ,to f9d ! radius ( a circle :5 ! area is giv53 ,divide ! area by #c4adaf & extract ! squ>e root ( ! quoti5t4 ,measurem5t ( ,solids4 ,to f9d ! lat]al area ( a "r prism3 ,multiply ! p]imet] ( ! base by ! altitude4 ,to f9d ! lat]al area ( a "r cyl9d]3 ,multiply ! circumf]5ce ( ! base by ! altitude4 ,to f9d ! volume ( a cyl9d] or prism3 ,multiply ! area ( ! base by ! altitude4 ,to f9d ! lat]al area ( a "r pyramid3 ,multiply ! p]imet] ( ! base by ! slant height & take half ! product4 ,to f9d ! lat]al area ( a cone3 ,multiply ! circumf]5ce ( ! base by ! slant height & take half ! product4 ,to f9d ! volume ( a pyramid or cone3 ,multiply ! area ( ! base by ! altitude & take "o-?ird ( ! product4 ,to f9d ! surface ( a sph]e3 ,multiply ! squ>e ( ! diamet] by #c4adaf4 ,to f9d ! volume ( a sph]e3 ,multiply ! cube ( ! diamet] by "o-six? ( #c4adaf or 4#ebcf4 ,9 a "r-angl$ triangle1 ! sum ( ! squ>es ( ! base & ! p]p5dicul> equals ! squ>e ( ! hypot5use4 ,to f9d ! l5g? ( ! hypot5use3 ,extract ! squ>e root ( ! sum ( ! squ>es ( ! base & ! p]p5dicul>4 ,to f9d ! base or ! p]p5dicul>3 ,f ! squ>e ( ! hypot5use subtract ! squ>e ( ! o!r giv5 side & extract ! squ>e root ( ! rema9d]4 ,,*apt] ,,xxi4 ,,gloss>y ,,( ,,electrical1 ,,me*anical1 ,,& ,,optical ,,words1 ,,t]ms1 ,,& ,,phrases4 ,ab]ration4--,! conv]g5ce to diff]5t foci1 by a l5s or mirror1 ( rays ( light emanat+ f "o & ! same po9t or ! deviation ( su* f a s+le focus4 a4 c4--,an abbreviation = alt]nat+ curr5t4 ,accumulator4--,a t]m (t5 us$ to designate a /orage batt]y4 ,a*romatic4--,free f false coloration4 ,a*romatic ,l5s4--,a l5s :i* does n %[ color 9 ! light :i* x projects2 usually a comb9ation ( l5ses ( diff]5t k9ds ( glass4 ,act9ic ,rays4--,! rays ( light t cause *emical *anges4 ,airdome4--,a !at] arrang$ 9 ! op5 air4 ,alloy4--,any comp\nd ( two or m metals4 ,alt]nat+ ,curr5t4--,an electric curr5t und]go+ p]iodical *anges 9 direction4 ,amalgam4--,a comp\nd ( m]cury ) o!r metals4 ,ammet]4--,an in/rum5t us$ = measur+ ! value ( an electric curr5t4 ,amp]age4--,! numb] ( amp]es2 ! curr5t /r5g? 9 ! circuit2 n ! quantity b ! rate ( fl[4 ,amp]e4--,! unit ( curr5t /r5g?4 ,x is equal to a rate ( fl[ ( electricity ( "o c\lomb p] second4 ,amp]e ,h\r4--,"o amp]e fl[+ = "o h\r2 or its equival5t4 ,anamorphosis4--,a grossly di/ort$ image1 su* z c be obta9$ f a curv$ mirror4 ,angul> ,velocity4--,! rate at :i* a body revolves ar\nd a fix$ axis1 usually measur$ 9 radians p] second4 ,! radian is equal to #cfj #b degrees4 ,annul> ,space4--,! space betwe5 an inn] & an out] r+ or cyl9d]4 ,annunciator4--,an electric device provid$ ) "o or m magnets & indicators1 :i* s]ve to indicate ! po9ts at :i* "o or m electric contacts h be5 clos$4 ,anode4--,! positive pole2 a t]m us$ mo/ly ) electrolytic devices1 also ) ! m]cury arc rectifi] & ! electric arc4 ,aplanatic4--,free f sph]ical ab]ration4 ,app>5t ,p[]4--,! product ( volts & amp]es 9 an alt]nat+-curr5t circuit4 ,! true p[] 9 an alt]nat+-curr5t circuit is always less ?an ! app>5t p[] if pressure & curr5t are n 9 phase4 ,arbor4--,an axle or sp9dle on :i* a :eel turns4 ,arc1 ,electric4--,! heat$ portion ( an electric circuit betwe5 two electrodes :]e ! curr5t passes f "o to ! o!r2 ! s\rce ( light ( ! electric arc lamp4 ,armature4--,t "p ( a g5]ator1 9 :i* ! electrical pressure is g5]at$1 :i* causes a curr5t if ! armature w9d+ =ms "p ( a clos$ circuit4 ,automatic4--,a t]m appli$ to ma*9]y 9 :i* c]ta9 movem5ts1 usually made by h&1 are made by ! ma*9e4 ,auto-,trans=m]4--,a trans=m] provid$ ) only "o w9d+2 a "p ( ! w9d+ be+ trav]s$ by bo? ! prim>y & second>y curr5ts4 ,axis4--,! /raight l9e1 real or imag9>y1 :i* passes ?r\gh a body1 & on :i* ! body revolves1 or may be suppos$ to revolve4 ,axis ( ,l5s4--,! /raight l9e pass+ ?r\gh its c5t] & p]p5dicul> to its surface4 ,axle4--,a transv]se b> connect+ opposite :eels4 ,babbitt ,metal4--,a s(t :ite antifriction metal ( v>y+ composition2 z #d p>ts ( copp]1 #h ( antimony1 & #bd or #if ( t94 ,! l>g] ! am\nt ( t91 ! h>d] ! resultant alloy4 ,baby ,spot ,lamp4--,an inc&esc5t lamp plac$ )9 a hood simil> to t ( a !at] arc lamp2 also usually provid$ ) a l5s4 ,back ,focus4--,?is t]m is us$ to designate ! di/ance f ! l5s ne>e/ ! slide to ! position ( ! slide :5 ! picture is 9 focus on ! scre54 ,see also ,equival5t ,focus4 ,balance ,:eel4--,a :eel add$ to ma*9]y = ! purpose ( prev5t+ too sudd5 v>iations 9 spe$2 also call$ fly :eel4 ,ball ,be>+4--,a j\rnal fitt$ ) balls ^u :i* ! %aft turns4 ,balsam1 ,canadian4--,a cem5t us$ to cem5t l5ses1 etc4 ,b&4--,a small belt pass+ ov] two pulleys4 ,batt]y4--,a t]m us$ to describe a numb] ( voltaic cells connect$ s z to act z a s+le cell2 %\ld nev] be us$ 9 ref]5ce to a s+le cell4 ,bayonet4--,a p9 :i* plays 9 & out ( holes made to receive x & s]ves to engage p>ts ( ma*9]y4 ,be>+4--,t "p ( a ma*9e 9 contact ) :i* a %aft moves2 ! j\rnal boxes4 ,b$4--,! f\ndation or ma9 fix$ "p ( a ma*9e4 ,bell ,crank4--,a rectangul> lev] by :i* ! direction ( rotation is *ang$ ?r\gh an angle ( n9ety degrees4 ,belt4--,a /rap or b& ( flexible mat]ial pass+ ar\nd two or m :eels & communicat+ motion to !m4 ,bevel ,ge>4--,a ge> 9 :i* ! two :eels work+ toge!r lie 9 planes t are n p>allel4 ,bifocal4--,hav+ two foci4 ,b9ocul>4--,p]ta9+ to bo? eyes1 z b9ocul> vision 9 microscope or telescope4 ,bl9d+ ,lights4--,lights us$ on ! /age 9 c]ta9 acts to bl9d ! audi5ce2 ?us all[+ p]sons to "w beh9d !m unse5 by ! audi5ce4 ,boss4--,! enl>g$ "p ( a %aft on :i* a :eel is key$4 ,brace4--,a curv$ tool ( iron or wood adapt$ to turn & hold bits4 ,brake4--,a piece ( me*anism adapt$ to /op or hold p>ts ( ma*9]y4 ,bru%es4--,t "p ( a dynamo by :i* ! curr5t is tak5 to or f ! commutator4 ,buff]4--,a cu%ion1 ) spr+s or o!r mat]ial1 arrang$ to dead5 ! bl[ ( a mov+ body4 ,buff+ ,:eel4--,a rapidly revolv+ :eel adapt$ to buff or poli% mat]ials4 ,burn]2 ,automatic1 ,electric4--,an electric device1 = turn+ on & light+ gas1 :i* may be op]at$ f a di/ance by press+ a button4 ,bu%+4--,! l9+ ( a hole ) a r+ or a p]=at$ sub/ance ( metal or o!r mat]ial4 ,calip]s4--,a compass ) curv$ legs2 us$ = measur+ r\nd b>s or op5+s1 ! ?ickness ( objects1 & ! di/ance betwe5 two po9ts4 ,cam4--,a project+ "p ( a :eel or o!r mov+ piece1 s %ap$ z to give an alt]nat+ or v>iable motion to ano!r piece press+ aga9/ x4 ,cam ,:eel4--,a :eel1 or "p ( a :eel1 ( irregul> outl9e employ$ to produce a v>iable or alt]nat+ motion 9 ma*9]y4 ,canadian ,balsam4--,a cem5t us$ to cem5t l5ses1 etc4 ,c&le ,p[]4--,?is t]m1 z commonly us$1 d5otes ! light-giv+ p[] ( a lamp 9 t]ms ( a /&>d c&le4 ,its mean+ is n v def9ite unless qualifi$ by "s ( ! foll[+ t]ms3 app>5t c&le p[]2 equival5t c&le p[]2 mean horizontal c&le p[]2 mean l[] hemisph]ical c&le p[]2 mean sph]ical c&le p[]2 maximum c&le p[]2 mean zonul> c&le p[]4 ,all ( ^! t]ms are fully expla9$ 9 8,mod]n ,electric ,illum9ation1 ,!ory & ,practice40 ,c>bons4--,! rods ( artificial c>bon us$ z electrodes 9 arc lamps4 ,c>bons1 ,cor$4--,c>bons1 z above1 b provid$ ) a core ( s(t] mat]ial4 ,case ,h>d5+4--,! act or process ( conv]t+ ! surface ( iron into /eel :ile leav+ ! c5t] s(t & malleable4 ,ca?ode4--,! negative pole4 ,a t]m usually us$ 9 connection ) electrolytic app>atus1 m]cury arc rectifi]s1 & electric arcs4 ,cell1 ,voltaic4--,a cup or j> conta9+ electrodes & an electrolyte ei!r = produc+ an electromotive =ce or electrolysis4 ,9 ! latt] case x is call$ an electrolytic cell4 ,a numb] ( cells connect$ toge!r make a batt]y4 ,c5ti4--,z a prefix x means ! hundr$? "p2 z c5timet]4 ,*oke ,coil4--,a coil ( wire w\nd ^u an iron core 9 su* a mann] z to acquire a v high self-inductance2 simil> to a reactance4 ,*uck4--,a contrivance fix$ to ! m&ril ( a turn+ la! = hold+ ! mat]ial to be work$ ^u4 ,clut*4--,a project+ too?1 or o!r piece ( ma*9]y1 = connect+ %afts ) ea* o!r or ) :eels 9 su* a mann] z to be readily dis5gag$4 ,cog ,:eel4--,a :eel ) cogs or tee?4 ,coll>4--,a r+-l "p ( a ma*9e usually fa/5$ to "s "p ( x & us$ = keep+ some?+ 9 place4 ,commutator4--,t "p ( a dynamo-electric ma*9e to :i* all ( ! armature wires are connect$ & 9 :i* ! alt]nat+-electromotive =ce1 actually g5]at$ 9 ! armature w9d+1 is made to appe> z a direct-electromotive =ce 9 ! ext]nal circuit4 ,compasses4--,an in/rum5t = describ+ circles1 measur+1 etc41 consi/+ ( two po9t$ bran*es fa/5$ toge!r at ! top by a rivet or screw4 ,comp5s>c4--,a trade t]m us$ to describe a trans=m] or an auto-trans=m]2 us$ 9 connection ) projection-arc lamps4 ,comp\nd ,w9d+4--,a g5]ator1 9 :i* ! fields are provid$ ) a %unt w9d+ & 9 addition ) a s]ies w9d+ :i* c>ries all ( ! curr5t ar\nd ! fields2 is said to be comp\nd w\nd1 & ! w9d+ is ref]r$ to z a comp\nd w9d+4 ,concave4--,curv$ & holl[2 ! inside ( a holl[ sph]e or cyl9d]4 ,conc5tric4--,hav+ a common c5t]4 ,cond5s]4--,a l5s or a set ( l5ses1 us$ to ga!r ! div]g5t rays f a s\rce ( illum9ation & br+ !m to a focus4 ,conductor4--,any sub/ance us$ to c>ry electricity4 ,mo/ ( ! comm]cial conductors are ( copp]4 ,cone4--,a solid body hav+ a plane = its base & a po9t = its top1 ! surface be+ =m$ by l9e segm5ts jo9+ e po9t ( ! outl9e ( ! base to ! po9t top4 ,conical4--,approximat+ a cone 9 %ape4 ,conjugate ,foci4--,! two po9ts 9 ! pr9cipal axis ( a l5s & at opposite sides ( x2 "o po9t be+ ! light s\rce & ! o!r ! po9t at :i* rays ( light f ?is s\rce are br\ght to a focus4 ,controll]4--,a resi/ance us$ = controll+ ! spe$ ( a motor or ! field /r5g? ( a dynamo4 ,conv]t]4--,any app>atus us$ = *ang+ f "o =m ( curr5t to ano!r2 g5]ally us$ to indicate a syn*ron\s or rot>y conv]t]4 ,convex4--,ris+ or swell+2 ! outside ( a sph]e or cyl9d]4 ,convexo-,plano4--,convex on "o side & plane on ! o!r2 plano-convex is m (t5 us$4 ,cool+ ,plate4--,! metal ar\nd ! projection ap]ture ( a motion-picture ma*9e :i* protects ! film f ! rays ( light4 ,cott]4--,a w$ge-%ap$ piece ( wood1 iron1 or o!r mat]ial us$ = fa/5+ ! p>ts ( a /ructure2 a key4 ,cott] ,p94--,a p9 made up ( d\bl$ wire exp&$ at top & bottom s z to hold its place :5 ins]t$ 9 a hole4 ,c\lomb4--,! unit ( quantity ( electricity4 ,x is equal to ! curr5t multipli$ by ! "t t x fl[s2 viz41 amp]e times second4 ,c\nt]%aft4--,a second>y %aft driv5 f ano!r %aft2 n ! ma9 or driv+ %aft4 ,c\nt]s9k4--,a drill or cutt+ tool us$ to enl>ge ! out] edges ( a hole 9 c\nt]s9k+4 ,cr[n ,:eel4--,a :eel1 ) cogs or tee? set at "r angles to its plane4 ,cycle4--,a complete recurr5ce ( any p]iodic *ange4 ,! two imm$iately succe$+ half waves ( an alt]nat+ curr5t or e4m4f4 con/itute a cycle4 ,damp+ ,coils1 ,damp]s4--,coils ( wire or b>s ( copp] plac$ on1 or imb$d$ 91 ! pole pieces ( a dynamo-electric ma*9e2 us$ mo/ly 9 connection ) syn*ron\s motors or rot>y conv]t]s to prev5t hunt+4 ,dead ,c5t]4--,ei!r ( ! two opposite po9ts1 9 ! orbit ( a crank1 at :i* ! crank & a driv+ rod lie 9 a /raight l9e4 ,diffus+ ,globes4--,globes ( gr\nd glass or o!r m$ium :i* causes diffusion ( light4 ,us$ to r$uce ! intr9sic brilliancy ( illum9ants4 ,! light is emitt$ f a l>g] surface & is less try+ to ! eyes4 ,diffusion4--,! scatt]+ ( light by diffuse reflection1 z f an irregul> surface su* z gr\nd glass4 ,diffusion ,projection4--,a me?od ( projection sometimes resort$ to :5 cond5s]s are brok54 ,gr\nd glass is us$ 9 place ( ! cond5s]s4 ,direct ,curr5t4--,a curr5t ( electricity ma9ta9$ 9 "o direction z di/+ui%$ f an alt]nat+ curr5t :i* is regul>ly alt]nat+ 9 direction4 ,dog4--,a "p ( ma*9]y act+ z a cat* or a clut*4 ,dovetail4--,to unite by a t5on1 9 ! =m ( a pigeon's tail spread out1 let into a bo>d or timb]4 ,d[el ,p94--,a p9 ( wood or metal us$ = jo9+ two pieces2 "p ( its l5g? ent]+ "o piece1 & ! re/ ent]+ a correspond+ hole 9 ! o!r4 ,d[s]4--,a h& %utt] arrang$ 9 front ( ! l5s ( an arc lamp by :i* ! light may be %ut (f4 ,drift4--,a conical tool ( /eel = enl>g+ or %ap+ a hole 9 metal by be+ driv5 into or ?r\gh x4 ,drill4--,a po9t$ in/rum5t us$ = bor+ holes2 especially 9 h>d sub/ances4 ,drop 9 ,pot5tial4--,a t]m (t5 us$ to designate a loss ( electrical pressure4 ,9 d4c4 circuits x is equal to curr5t times resi/ance4 ,9 a4c4 circuits x is equal to curr5t times imp$ance4 ,drum4--,a %ort cyl9d] revolv+ on an axis4 ,dynamo4--,a dynamo electric ma*9e = conv]t+ electrical en]gy into me*anical1 or vice v]sa4 ,:5 ! trans=mation is f electrical to me*anical en]gy ! ma*9e is op]at+ z a motor2 & :5 ! trans=mation is f me*anical to electrical en]gy ! ma*9e is op]at+ z a g5]ator4 e4 f4--,abbreviation = equival5t focus4 e4 m4 f4--,abbreviation = electromotive =ce4 ,! unit ( electromotive =ce4 ,! unit ( electromotive =ce is ! volt4 ,ecc5tric4--,a :eel or disc hav+ its axis ( revolution out ( its c5t]2 us$ to conv]t circul> motion into reciprocat+4 ,economiz]4--,a trade "n appli$ to a trans=m] or auto-trans=m]1 us$ 9 connection ) projection-arc lamps4 ,economy ,coils4--,an auto-trans=m]4 ,?is t]m is us$ v mu* 9 connection ) auto-trans=m]s1 & also trans=m]s us$ 9 connection ) arc lamps4 ,effici5cy ( ,inc&esc5t ,lamps4--,! effici5cy ( inc&esc5t lamps is express$ 9 watts p] c&le p[]4 ,! l[] ! num]ical expression = effici5cy1 ! great] is ! light obta9$ p] unit ( en]gy4 ,electrodes4--,! t]m9als ( an electric s\rce2 9 an arc lamp1 ! two c>bons4 ,electrolysis4--,*emical decomposition by an electric curr5t4 ,! positive pole1 or anode1 is eat5 away ) direct curr5t2 ! effect ) alt]nat+ curr5t is v slight4 ,em]g5cy ,lights4--,^? lights arrang$ 9 !at]s1 ! object ( :i* is to furni% ! necess>y illum9ation by :i* ! audi5ce may leave ! !at] 9 case ( a failure ( ! regul> illum9ation4 ,em]g5cy & exit lights are g5]ally gr\p$ toge!r b mu/ n be confus$ ) ea* o!r4 ,equival5t ,focus4--,! di/ance f ! c5t] ( a set ( l5ses to ! slide1 :5 ! picture on ! slide is 9 focus on ! scre54 ,exit ,lights4--,! lights plac$ directly above exits2 usually color$ r$4 ,expansion ,bolt4--,a bolt adapt$ to be ins]t$ into a socket :i*1 exp&$ by ! ins]tion1 ?us holds ! bolt 9 place4 ,face ,plate4--,! disc atta*$ to ! revolv+ sp9dle ( a la! to :i* ! "w is (t5 fa/5$4 ,fe$]s4--,! ma9 wires ext5d+ f ! supply to ! di/ribut+ c5t]4 ,field4--,a t]m commonly us$ to designate ! space trav]s$ by ! l9es ( ! =ce ( magnetism :i* is suppos$ to exi/4 ,! fields ( a dynamo consi/ ( ! pole pieces ar\nd :i* ! excit+ curr5t circulates4 ,fire ,trap4--,! arrangem5t ( roll]s & _! enclosure1 usually plac$ on magaz9e or film tanks1 ?r\gh :i* ! film is l$1 to prev5t a flame f foll[+ ! film 9 case ( fire4 ,flange4--,a project+ edge or rim on a :eel or %aft by :i* x may be kept 9 place or fa/5$4 ,fla%]4--,! t]m by :i* a contrivance = regul>ly1 & at frequ5t int]vals1 turn+ lights on & (f is describ$2 us$ mo/ly 9 connection ) electric signs4 ,flick]4--,! un/eady illum9ation ( a motion picture2 caus$ mo/ly by insuffici5t spe$ ( film or too brilliant illum9ation4 ,fly ,floor4--,a floor above ! /age ^u :i* ! sc5e %ift]s1 ^: duty x is to raise & l[] ! curta9s1 "w4 ,footlights4--,a r[ ( lights plac$ at ! /age level & directly 9 front ( ! actors4 ,=g+4--,a piece ( metal %ap$ by hamm]+2 n a ca/+4 ,fram+ ,device4--,a device atta*$ to e motion-picture ma*9e by :i* ! relative position ( ! film to ! optical sy/em may be adju/$ to make ! picture appe> 9 its prop] place on ! scre54 ,frequ5cy4--,! numb] ( cycles p] second2 also spok5 ( z ! p]iodicity4 ,! mo/ common frequ5cies are #be & #fj cycles p] second4 ,ge>+4--,! p>ts by :i* motion giv5 to "o "p ( a ma*9e is transmitt$ to o!r p>ts4 ,9 a n>r[] s5se x ref]s only to cog :eels4 ,a spur ge> is "o 9 :i* ! tee? are arrang$ ei!r on ! outside or inside ( ! rim 9 ! direction ( radii f ! c5t] ( ! :eel4 ,a bevel ge> is "o 9 :i* ! %afts ( ! two ge>s are n p>allel4 ,a friction ge> is "o 9 :i* friction takes ! place ( ! tee?4 ,a worm ge> is "o 9 :i* "o ( ! memb]s is 9 ! =m ( a screw4 ,! pit* ( ! screw may1 or may n1 be su* z to prev5t x f be+ turn$ by ! o!r4 ,a h]r+-bone ge> is "o 9 :i* ! tee? are cut across ! face ( ! :eel at an angle4 ,! tee? may be made to conv]ge t[>d ! c5t] ( ! face or may be cut 9 a l9e across x4 ,?is ge> is us$ :]e noiseless op]ation is requir$4 ,g5]ator4--,a t]m frequ5tly us$ to describe a dynamo-electric ma*9e us$ 9 conv]t+ me*anical en]gy into electrical en]gy4 ,g5eva4--,a =m ( int]mitt5t movem5t fir/ us$ 9 ,g5eva1 ,switz]l&2 h5ce ! "n4 ,x is ! =m ( int]mitt5t me*anism mo/ us$4 ,gov]nor4--,a contrivance us$ 9 connection ) ma*9]y to regulate ! spe$4 ,grid1 or ,grid ,floor4--,?is t]m ref]s to ! topmo/ floor above ! /age ( a !at] :]e ! pulleys & ! cables1 by :i* sc5]y is rais$ & l[]$1 are plac$4 ,x is usually made up ( iron b>s ) spaces betwe5 !m2 h5ce ! "n4 ,gr\nd4---,?is t]m is us$ to describe any connection ( an electrical conductor to any conduct+ m$ium1 o!r ?an t to :i* x belongs1 :i* may be common to o!r conductors or :i* may convey curr5t to ! opposite pole 9 a mann] n desir$4 ,gudgeon4--,! piece ( iron 9 ! end ( a wood5 %aft on :i* x turns 9 a coll> or on a gudgeon block4 ,heat ,%ield4--,a "p ( a motion-picture ma*9e :i* %ields ! film & adjac5t p>ts f ! heat ( ! light4 ,helix4--,see ,sol5oid4 ,horsep[]4--,a unit or /&>d by :i* ! capability ( ma*9]y is measur$4 ,p[] suffici5t to raise "o p\nd #cc1jjj feet 9 "o m9ute is call$ "o horsep[]4 ,electrically x is equal to #gdf watts4 ,hunt+4--,?is t]m describes ! regul> & p]si/5t *anges 9 ! spe$ ( syn*ron\s app>atus runn+ 9 p>allel1 :i* are due to fluctuations 9 ! load on ! g5]ators or 9 ! spe$ ( ! prime mov]2 & causes cross curr5ts4 ,9 !at]s !y w\ld be noticeable only 9 connection ) rot>y conv]t]s :i* are sometimes us$ to conv]t a4c4 into d4c4 = arc lamps4 ,idl]4--,a :eel plac$ betwe5 two o!r :eels to convey motion f "o to ! o!r )\t *ang+ ! direction ( motion4 ,imp$ance4--,imp$ance is to an alt]nat+-curr5t circuit :at resi/ance is to a direct-curr5t circuit4 ,! e4m4f4 divid$ by ! imp$ance equals ! curr5t4 ,! symbol = imp$ance is ,z4 ,impress$ e4m4f4--,! electromotive =ce br\ght to be> on any circuit to produce a curr5t !re92 ! appli$ e4m4f4 ,index ( ,refraction4--,! index ( refraction1 or ! refraction index1 is ! ratio ! s9e ( ! angle ( incid5ce be>s to ! s9e ( ! angle ( refraction4 ,= glass ! index ( refraction is ab\t #a4e4 ,indirect ,light+4--,a sy/em ( illum9ation 9 :i* all ( ! light is fir/ ?r[n to ! ceil+ & reflect$ !refrom4 ,inductance4--,t prop]ty ( an electric circuit :i* causes a curr5t 9 x to create l9es ( =ce & ?us g5]ate a c\nt] e4m4f4 :5 ! curr5t *anges 9 value4 ,induction ,motor4--,a mu* us$ alt]nat+-curr5t motor 9 :i* !re is no electrical connection betwe5 ! prim>y & second>y or rotor & /ator w9d+s4 ,x may be ei!r s+le or polyphase4 ,int]mitt5t ,movem5ts4--,!re are num]\s types ( int]mitt5t movem5ts b ! ,g5eva & ! p9 cross are ! only ones us$ ) ! late/ types ( motion-picture projection ma*9es4 ,! o!r movem5ts h mo/ly come into use 9 connection ) cam]as4 ,! beat] movem5t is "o 9 :i* a c]ta9 l5g? ( film is pu%$ to "o side at ea* movem5t4 ,! claw movem5t is "o 9 :i* claws rea* up & pull d[n a fix$ am\nt ( film at ea* movem5t4 ,o!r int]mitt5t movem5ts are kn[n z1 ! drunk5 screw2 rat*et2 pitman & grip4 ,!y h mo/ly only a hi/orical int]e/4 ,intr9sic ,brilliancy4--,?is t]m ref]s to ! c&le p[] p] unit area ( a s\rce ( light4 ,a light hav+ a l>ge c&le p[] 9 proportion to its size is said to h a high intr9sic brilliancy4 ,lamps ( high intr9sic brilliancy %\ld nev] be plac$ 9 ! l9e ( vision4 ,inv]t$ ,light+4--,synonym\s ) indirect light+4 ,key4--,a w$ge-%ap$ piece ( wood or metal us$1 to hold some?+ 9 place2 a cott]4 ,key ,seat4--,a groove cut into a %aft to fit a simil> groove 9 a :eel or flange1 & into :i* a key may be fitt$4 ,key to ,curta94--,a fictiti\s article1 9 que/ ( :i* novices employ$ 9 !at]s are (t5 s5t2 a hoax4 ,kil[att4--#ajjj watts4 ,lagg+ ,curr5t4--,a curr5t1 ! maximum value ( :i* occurs lat] ?an t ( ! e4m4f4 produc+ x4 ,lam9at$4--,made up ( %eets4 ,all iron p>ts subject to ! influ5ce ( alt]nat+ fields mu/ be lam9at$ to r$uce ! losses due to ,f\cault or eddy curr5ts4 ,lead+ ,curr5t4--,a curr5t1 ! maximum value ( :i* occurs e>li] ?an t ( ! e4m4f4 produc+ x4 ,9 connection ) syn*ron\s conv]t]s ! curr5t may be made ei!r lagg+ or lead+ by adju/+ ! field excitation4 ,l5s4--,a piece ( glass1 or o!r transp>5t sub/ance1 gr\nd ) two opposite regul> surfaces4 ,9 practice ! curv$ surfaces are g5]ally sph]ical b sometimes !y are made cyl9drical4 ,( sph]ical l5ses !re are six v>ieties3 plano-concave2 d\ble-concave2 plano-convex2 d\ble-convex2 m5iscus2 & concave-convex4 ,a d\ble-convex l5s1 ) "o radius six times t ( ! o!r1 is call$ a cross$ l5s4 ,a multiply+ l5s or glass is "o consi/+ ( a numb] ( plane faces on "o side & a convex surface on ! o!r4 ,! plane faces are incl9$ to "o ano!r & ea* pres5ts a diff]5t picture2 ?us giv+ ! appe>ance ( ! multiplication ( images4 ,a polyzonal l5s is "o t is made up ( a l>ge numb] ( pieces arrang$ 9 zones or r+s4 ,?is k9d ( l5s is us$ only = sizes 9 :i* x is difficult to use pieces l>ge en\gh to h ! l5s 9 "o piece4 ,lime ,light4--,a light produc$ by means ( a cyl9d] ( lime :i* is subject$ to a flame ( gas or ( oxyg5 & hydrog54 ,l9es ( ,=ce4--,e magnetic field is suppos$ to be made up ( imag9>y l9es call$ l9es ( =ce4 ,! numb] ( ^! l9es p] unit area p]p5dicul> to ! field is a measure ( ! /r5g? ( ! field4 ,lo/ ,motion4--,ref]s to ! loss or irregul>ity ( motion caus$ by we> ( ma*9]y or poor adju/m5t4 ,magic ,pane4--,?is is a cond5s] =m$ ( a %eet ( glass1 "o side ( :i* is cov]$ by pieces ( t9 foil ) spaces left betwe54 ,! spaces betwe5 may be arrang$ to repres5t any design & on ! dis*>ge ( ! cond5s] ! design is illum9at$ by ! sp>ks :i* jump ov] ! spaces4 ,male ,?read or ,c\pl+4--,9 connection ) pip+1 hose1 etc41 a c\pl+ arrang$ to ent] into ano!r1 is spok5 ( z 8male02 t "p :i* is ent]$ into is kn[n z 8female40 ,m&rel4--,a b> ( metal ins]t$ 9 ! "w to hold x1 z 9 a la!1 dur+ ! process ( manufacture4 ,also ! sp9dle :i* c>ries ! c5t] *uck ( a la!1 an arbor4 ,mat*$ ,l5ses4--,! l5ses 9 two /]eopticon lamps to be us$ toge!r mu/ be mat*$ to give ! same size ( picture4 ,micromet]4--,an in/rum5t us$ = measur+ v small diamet]s or ?icknesses1 ! adju/m5ts be+ made by a screw arrang$ to indicate v slight *anges 9 ! op5+ 9 :i* ! object is ins]t$4 ,mil4--,! "o-?\s&? "p ( an in*4 ,! circul>-mil area ( a circul> area1 su* z ! cross section ( a wire1 c be f\nd by squ>+ ! diamet]4 ,mirage4--,an optical illusion due to an unequal refraction 9 ! l[] atmosph]e :i* causes remote objects to be se5 d\ble & susp5d$ 9 ! air4 ,a mirage c be arrang$ = by a prism or by a piece ( bevel$ glass4 ,mit] ,:eels4--,a pair ( bevel :eels ( equal diamet] work+ toge!r1 usually ) _! axes at "r angles4 ,motion ,head4--,by ?is t]m ! :ole ( ! motion-picture ma*9e is usually designat$4 ,motor4--,see dynamo4 ,motor ,g5]ator4--,a g5]ator driv5 by a motor4 ,multiple ,s]ies4--,a sy/em ( wir+ 9 :i* sev]al lamps are connect$ 9 s]ies & a numb] ( su* s]ies comb9ations connect$ 9 multiple4 ,neutral ,wire4--,! wire ( a ?ree-wire sy/em :i* ord9>ily c>ries no curr5t4 ,9 a ?ree-wire sy/em x is usually run 9 ! c5t]4 ,ohm4--,! ohm is ! unit ( electrical resi/ance4 ,ohmic ,drop4--,?is is ! loss ( pot5tial due to ! resi/ance1 z di/+ui%$ f t due to ! reactance4 ,x is always equal to ! curr5t multipli$ by ! resi/ance1 ! curr5t be+ measur$ 9 amp]es & ! resi/ance 9 ohms4 ,ohm's ,law4--,?is is a /atem5t def9+ ! relations exi/+ betwe5 electrical pressure1 curr5t1 & resi/ance4 ,! curr5t is equal to ! electrical pressure divid$ by ! resi/ance4 ,! resi/ance is equal to ! electrical pressure divid$ by ! curr5t4 p4 d4--,an abbreviation = diff]5ce ( pot5tial4 ,pawl4--,a %ort movable piece or b> connect$ at "o end1 by a jo9t1 ) "s "p ( a ma*9e2 :ile ! o!r end falls into not*es or tee? on ano!r "p1 9 su* a mann] z to p]mit motion 9 "o direction only4 ,p]iod4--,! "t requir$ = "o complete cycle4 ,photomet]4--,an in/rum5t us$ = comp>+ or measur+ ! c&le p[] ( illum9ants4 ,p9ion4--,a small :eel ) leaves or tee? work+ into ! tee? ( a l>g] :eel or rack2 especially su* a :eel hav+ its leaves =m$ ( ! sub/ance ( ! arbor or sp9dle on :i* x turns2 a too!d arbor4 ,pit*4--,! di/ance f c5t] to c5t] ( any two adjac5t tee? ( ge>+ measur$ on ! pit* l9e4 ,! di/ance measur$ on a l9e p>allel to ! axis betwe5 two adjac5t ?reads or convolutions ( a screw4 ,pit* ,l9e4--,a circle conc5tric ) ! circumf]5ce ( a too!d :eel & cutt+ its tee? at su* a di/ance f _! po9ts z to t\* ! correspond+ circle ( ! ge> work+ ) x4 ,! two circles mu/ h a common velocity4 ,plung]4--,a "p ( ma*9]y :i* is subject to a plung+ motion4 ,pol>ity4--,a diff]5ce ( pol>ity exi/s betwe5 any two wires1 or po9ts 9 "o wire1 :]e !re is any t5d5cy to produce a curr5t4 ,9 practice1 h[ev]1 ! t]m is us$ to designate wires p]ta9+ to ! two opposite poles ( a sy/em4 ,polyphase4--,ref]r+ to m ?an "o phase1 multiphase4 ,p[]4--,?is t]m designates ! rate ( do+ "w4 ,p[] ,factor4--,?is t]m expresses ! ratio ( ! true p[] 9 an alt]nat+-curr5t circuit to ! app>5t p[]4 ,x is always less ?an #a4 ,! app>5t p[] 7product ( volts & amp]es measur$ by indep5d5t in/rum5ts7 mu/ be multipli$ by ! p[] factor to obta9 ! true p[] 9 alt]nat+-curr5t circuits4 ,prim>y ,batt]y4--,a batt]y 9 :i* ! p4d4 is produc$ by prim>y action ( ! +r$i5ts us$1 in/ead ( by second>y action z 9 second>y batt]ies or accumulators4 ,prim>y ,coil4--,t coil ( a trans=m]1 induction motor1 or induction coil :i* is connect$ to ! s\rce ( electrical en]gy4 ,prism4--,a transp>5t body usually hav+ ?ree rectangul> faces & triangul> ends4 ,x is us$ 9 exp]im5ts on optics to %[ refraction & may also be made to produce total reflection4 ,prismatic ,colors4--,! sev5 colors into :i* sunlight is resolv$ :5 pass$ ?r\gh a prism4 ,an a*romatic prism is "o made up ( two k9ds ( glass ( diff]5t disp]sive p[]s by :i* a ray ( light may be refract$ )\t %[+ color4 ,pulley4--,a broad-rimm$ :eel us$ = transmitt+ p[] by means ( a belt4 ,a n>r[-rimm$ :eel ) a groove us$ = ! same purpose is t]m$ a %eave4 ,a cone pulley is a pulley made 9 ! %ape ( a cone & us$ 9 conjunction ) a simil> pulley & a belt connect+ !m = ! purpose ( v>y+ ! velocity4 ,a fa/ pulley is "o :i* is rigidly atta*$ to ! %aft4 ,a loose pulley is "o :i* is us$ 9 conjunction ) ano!r pulley ( ! same size to c>ry ! belt :ile ! %aft atta*$ to ! o!r is /ill4 ,pulsat+ ,curr5t4--,a curr5t ( electricity v>y+ regul>ly 9 /r5g? b n 9 direction4 ,rack & ,p9ion4--,a /raight b> ) tee? on its edge to "w ) ! tee? ( a p9ion :i* is to drive or foll[ x4 ,rat*et4--,a b> or piece ( me*anism turn+ ^u a pivot :ile ! o!r end falls into ! tee? ( a :eel or rack all[+ ! latt] to move 9 "o direction only4 ,x may be us$ = prev5t+ backw>d motion 9 ma*9]y or = conv]t+ reciprocat+ motion into =w>d motion4 ,rat*et ,drill4--,a drill atta*$ to a rat*et4 ,rat*et ,:eel4--,a :eel hav+ tee? by :i* x may be mov$ =w>d z by a lev] & cat*1 or by a pawl arrang$ to engage ! tee?4 ,! pawl may also be arrang$ to engage ! tee? = ! purpose ( prev5t+ backw>d motion4 ,reactance ,coil4--,see ,*oke ,coil4 ,reactive ,drop4--,! drop 9 pot5tial caus$ ?r\gh ! pres5ce ( reactance 9 ! circuit1 z di/+ui%$ f t caus$ by ohmic resi/ance :i* is kn[n z ! ohmic drop4 ,rectifi]4--,any app>atus us$ to *ange an alt]nat+ curr5t to a direct curr5t by p]iodically int]rupt+ or *ang+ ! direction ( ! alt]nat+ curr5t s t ! d]iv$ curr5t is always 9 ! same direction4 ,relay4--,a device actuat$ by an electric curr5t to op5 or close ano!r circuit4 ,rheo/at4--,an adju/able resi/ance4 ,rock ,%aft4--,a %aft t vibrates or oscillates in/ead ( mak+ complete revolutions4 ,call$ also rock] or rock+ %aft4 ,rot>y ,conv]t]4--,a rotat+ ma*9e hav+ a field excit$ by a direct curr5t & an armature w9d+ connect$ to a commutator & a set ( collector r+s4 ,x is us$ to conv]t alt]nat+ curr5t into direct1 or vice v]sa2 also call$ syn*ron\s conv]t]4 ,rotor4--,! mov+ "p ( an alt]nat+-curr5t g5]ator or motor4 ,second>y ,batt]y4--,a /orage batt]y2 an accumulator4 ,second>y ,coil4--,! coil ( a trans=m] or an induction coil into :i* curr5ts are induc$2 ! coil :i* is n connect$ to ! s\rce ( en]gy4 ,s]ies ,connection4--,a connection 9 :i* a numb] ( devices are jo9$ s t ! same curr5t passes ?r\gh all ( !m4 ,s]ies ,multiple4--,a sy/em ( wir+ 9 :i* a numb] ( devices are connect$ 9 multiple & sev]al ( su* gr\ps !n connect$ 9 s]ies4 ,! same curr5t mu/ pass ?r\gh ea* gr\p4 ,%ak+ ,coil4--,a coil us$ 9 connection ) a m]cury-arc rectifi] = tilt+ or %ak+ ! tube & />t+ ! app>atus4 ,%unt4--,a by-pass4 ,a wire :i* c>ries "p or all ( ! curr5t 9 a circuit ar\nd "s o!r device connect$ 9 ! circuit4 ,s+le-,phase4--,an alt]nat+-curr5t sy/em us+ only two wires & only "o e4m4f4 ,x is sometimes t]m$ uniphase or monophase4 ,slip ( ,induction ,motor4--,! diff]5ce 9 ! numb] ( revolutions made by ! revolv+ field & ! rotor ( ! motor4 ,x is usually express$ 9 p] c5t ( ! syn*ron\s spe$ :i* is t ( ! revolv+ field4 ,sol5oid4--,a r\nd coil ( wire g5]ally us$ to control an iron core2 an electromagnetic helix4 ,spid]4--,a ca/+ or "p ( a ma*9e hav+ projections or arms radiat+ f x s z some:at to resemble a spid]4 ,sp9dle4--,! revolv+ arbor ( a ma*9e tool2 an axis4 ,spiral ,ge> or ,ge>+4--,a ge>+ consi/+ ( :eels work+ toge!r ) _! axes at an angle to ea* o!r d\ble t ( ! angle ( ! tee? ) ! axes4 ,x is sometimes us$ 9 light ma*9]y 9 place ( bevel ge>+4 ,spiral ,:eel4--,a :eel hav+ its tee? cut at an angle ) its axis or s t !y =m small p>ts ( screws or spirals4 ,spl9e4--,a rectangul> piece fitt+ ! key seats ( a hub & %aft s t1 :ile ! "o may slide endwise on ! o!r1 bo? mu/ revolve toge!r4 ,spur ,:eel4--,a :eel 9 :i* ! tee? are p]p5dicul> to ! axis & 9 ! direction ( ! radii4 ,/atic ,electricity4--,! "n usually giv5 to electricity g5]at$ by friction1 z f belt+ 9 ma*9e %ops1 etc4 ,/ator4--,! /ation>y "p ( an alt]nat+-curr5t motor or g5]ator4 ,/ay ,bolt4--,a bolt connect+ opposite plates to keep !m f bulg+4 ,/epd[n ,trans=m]4--,a trans=m] us$ = r$uc+ voltage4 ,/epup ,trans=m]4--,a trans=m] us$ = increas+ voltage4 ,/rik+ ! ,arc4--,! act ( br++ ! c>bons ( an arc lamp toge!r & imm$iately sep>at+ !m & e/abli%+ ! arc is call$ /rik+ ! arc4 ,/ud4--,a projection ( a bolt adapt$ to hold a lug or connection ( "s k9d4 ,/ud ,bolt4--,a bolt ) ?reads on bo? ends1 to be screw$ into a fix$ "p at "o end & receive a nut ^u ! o!r4 ,su/a9+ ,coil4--,! "n sometimes giv5 to a reactance us$ 9 connection ) a m]cury-arc rectifi] to cause an ov]lapp+ ( ! two curr5ts f ! anodes4 ,swivel or ,swivel ,jo9t4--,a jo9t1 ! two pieces ( :i* c be turn$ ar\nd indep5d5tly ( ea* o!r4 ,syn*ronism4--,be+ 9 "t or occurr+ at ! same "t 9 regul> ord] ) "s o!r ev5t4 ,syn*ron\s ,conv]t]4--,see rot>y conv]t]4 ,tap ,bolt4--,a bolt ) a head on "o end & a ?read on ! o!r to be screw$ into "s "p in/ead ( pass+ ?r\gh & be+ fa/5$ ) a nut4 ,?ree-,phase4--,ref]s to a sy/em ( electrical di/ribution mak+ use ( ?ree sep>ate curr5ts4 ,^! curr5ts may be sup]impos$ & g5]ally only ?ree wires are us$ 9 ! transmission4 ,?umb ,screw4--,a screw arrang$ s t x c be set up ) ! f+]s4 ,simil> to a w+ nut4 ,?umb ,spot4--,a di/+ui%+ m>k usually plac$ on /]eopticon slides s z to m>k ! spot at :i* ! ?umb ( ! "r h& %\ld be plac$ :5 ins]t+ ! slide to insure its prop] plac+ 9 ! hold]4 ,travel ,gho/4--,! peculi> hazy appe>ance (t5 se5 9 a motion picture2 x is produc$ by ! improp] sett+ ( ! revolv+ %utt]4 ,trunnion4--,projection lugs on ! sides ( "s piece ( ma*9]y ^u :i* x is support$ & ^u :i* x c move4 ,two-,phase4--,?is t]m ref]s to an a4c4 sy/em ( electrical di/ribution mak+ use ( two curr5ts ( diff]5t phase4 ,x may be arrang$ ) ?ree or f\r wires4 ,unbalanc$4--,?is t]m is us$ 9 connection ) ?ree-wire & ?ree-phase sy/ems4 ,! ?ree-wire sy/em is said to be unbalanc$ :5 "o ( ! outside wires is c>ry+ m curr5t ?an ! o!r4 ,! ?ree-phase sy/em is said to be unbalanc$ :5 ! load is unev5ly di/ribut$ ov] ! ?ree-phase wires4 ,univ]sal ,jo9t4--,a contrivance us$ = jo9+ two %afts or p>ts ( ma*9]y endwise s t "o may give rot>y motion to ! o!r :ile at an angle4 ,volt4--,! unit ( electromotive =ce4 ,voltmet]4--,an in/rum5t us$ = measur+ pot5tial diff]5ce4 ,wat] ,rheo/at4--,a resi/ance 9 :i* wat] is us$ to c>ry ! curr5t4 ,plates ( metal proportional to ! curr5t to be us$ are ins]t$ 9 ! wat] & by ins]t+ !m to a great] ext5t or mov+ !m clos] toge!r ! curr5t c be increas$4 ,watt4--,! unit ( p[]4 ,wattless ,curr5t4--,t "p ( an alt]nat+ curr5t :i* is ei!r ahead ( or beh9d ! e4 m4 f4 ( ! circuit4 ,watt ,met]4--,an in/rum5t us$ = measur+ electrical en]gy4 ,yoke4--,a clamp resembl+ an ox yoke some:at & adapt$ to jo9 two pieces ( a ma*9e4 ,,index ,,page ,ab]ration1 *romatic1 #ea ,ab]ration1 sph]ical1 #ea ,adju/+ int]mitt5t sprocket1 #ajj ,aisle lights1 #bah ,align+ ma*9e1 #if ,alt]nat+ curr5t1 #bah ,alt]nat+ curr5t motor1 #bae ,amp]age = projection1 #dc1 #dd ,amp]age1 det]m9ation (1 #de1 #df ,an*or+ ma*9e1 #ig ,anvil sp>ks1 #caa ,arc1 color (1 #ai1 #bj1 #ca ,enclos$1 #bc ,=m ( c>bons1 #bb ,l5g? (1 #ba ,l[ t5sion1 #bj ,op51 #bc ,resi/ance (1 #bj ,upside d[n1 #bb ,arc lamps1 #ai1 #bah1 #cab ,automatic1 #be ,edison1 #cf ,h& fe$1 #be ,kliegl1 #ce1 #cf ,mc,intosh1 #cd ,motiograph1 #cg ,op]ation (1 #be1 #bg ,p[]s1 #cg ,te/+ (1 #bh ,arc light1 injuri\s1 #ba ,armor$ cable1 #bbb ,asbe/os1 #bbf ,atta*m5t plugs1 #bbf ,auto-/>t]s1 #bbg ,automatic fire %utt]1 #fb1 #gj1 #ga1 #aja ,axis ( l5s1 #cfj ,baby spot lamp1 #caf ,balconies1 #bbh ,batt]ies1 #caf ,bells1 #bbh1 #cah ,bl9d+ lights1 #cai ,bord]s1 #bbi ,brackets1 #bcb1 #cai ,bran* circuits1 #bcb ,bran*-(f connectors1 #cdc ,bun* lights1 #cbj ,bus-b>s1 #bcd ,cab9ets1 #bce ,cables1 #bce ,call-bo>d1 #bic ,canopies1 #bcf ,cam]a lucida1 #aeb ,c>bons1 adju/+ (1 #ca ,be/ to use1 #bi ,cor$1 #ec ,sett+ (1 #ca1 #cb1 #cd ,te/+ (1 #bh ,c>e ( sprockets1 #ii ,c>riage call1 #bic ,c>ry+ capacity1 #bcg ,ceil+ fans1 #bcg ,*&eli]s1 #bcg1 #cba1 #cbb ,*romatic ab]ration1 #ea ,clean+ ma*9e1 #ih ,circuit break]s1 #bci ,colors = arc lamps1 #cbc ,color$ pictures1 #ei ,comp>ison ( /]eopticon & motion picture ma*9e pictures1 #di ,concavo-convex l5s1 #adf ,concave m5iscus l5s1 #adf ,conceal$ "w1 #bdj ,cond5s]s1 #ch1 #aec ,breakage1 #dj ,diamet] (1 #ea ,focal l5g? (1 #ej ,conduit "w1 #bdj ,conjugate foci ( l5s1 #adc ,conjugate foci ( mirror1 #acc ,contacts1 #bde ,convexo-concave l5s1 #adf ,convex m5iscus l5s1 #adf ,cord1 #bde ,correct$ l5ses1 #adh ,cov] = ma*9e1 #ajd ,critical angle ( refraction1 #adj ,curr5t control = arc lamps1 #aij ,auto-trans=m]1 #aie ,m]cury-arc rectifi]1 #bjg ,motor g5]ators1 #aih ,reactances1 #aic ,resi/ances1 #aij ,rot>y conv]t]s1 #bjb ,trans=mation1 #aid ,curr5t requir$ = projection1 #dc1 #dd ,curr5t taps1 #bde ,cut-outs1 #bdf ,damp places1 #bdi ,decorative light+ sy/ems1 #bdi ,dimm]s1 #bej ,dimm] box1 #cbd ,door swit*es1 #bea ,d\ble concave l5s1 #adf ,d\ble convex l5s1 #adf ,dress+ rooms1 #afh1 #bea ,drop lights1 #beb ,ed5graph motion head1 #hc1 #hf ,edison motion head1 #fd1 #hd ,effici5cy ( inc&esc5t lamps1 #bgj ,electric sign imitations1 #cbe ,electric /age effects1 #cbf ,em]g5cy light+ sy/em1 #bec ,equival5t focal l5g?1 #ej ,exit lights1 #bef ,explosions1 #cbg ,eye1 !1 #abd ,mix+ ( impressions1 #abe ,rega9+ ( vision by ag$1 #abe ,face-o-graph1 #afa1 #cbh ,fan motors1 #bef ,fe/oons1 #cbh ,film1 #hi ,box =1 #ajh ,burn+ (1 #ij1 #agc1 #agg ,emulsion on1 #hi ,fire1 #aaj ,gate1 #fb1 #fi1 #gj1 #ajb ,inspection (1 #aje ,lead]s & tails1 #ajf1 #ajg ,m5d]1 #id ,pat*+1 #ia1 #ic ,pictures1 p] foot1 #eg ,p9n+ (1 #aaj ,receptacle =1 #ajf ,rew9d+1 #ajh ,%ields1 #fb1 #hc ,/eadi] drum1 #fb1 #fi ,fire al>m1 #bef ,fire dance1 #ccj ,fire haz>d1 #aa ,fire flies1 #ccj ,fire places1 #cca ,fire pro( film1 #ij ,fire traps1 #fb1 #fg1 #ig ,te/+ (1 #fh ,fi% "w1 #bef ,fixtures1 #beg ,fla%]s1 #bei ,flexible cord1 #bfa ,flexible tub+1 #bfa ,flood lamps1 #bd ,floor pockets1 #bfa ,fl[]s1 #ccb ,fly door1 #bfa ,focal l5g? ( concave mirror1 #acc ,focus+1 #db ,foot-lights1 #bfa1 #bfb ,=mulas1 #cec ,f\nta9s1 #ccb ,fram+1 #ajb ,fram+ device1 #fb1 #hb ,friction roll]s1 #fb1 #fi ,fuses1 #ccc ,fuse spac+s1 #bhh ,gall]y light+1 #bfc ,gall]y pockets1 #bfc1 #cjj ,gas globes1 #ccd ,gas light+1 #bfd ,g5]ators1 managem5t (1 #bac 8,g5eva0 movem5t1 #gf1 #gg ,gett+ ready = ! %[1 #ajd 8,gho/01 #db ,glass %ades1 #ccd ,gloss>y ( me*anical1 electrical & optical words1 t]ms & phrases1 #ceh ,grid floor1 #bfe ,gr\nd1 #aa ,gr\nd+1 #bfe ,gu>ds1 #bff ,hang] bo>ds1 #bff ,heat1 #aae ,heat]s1 #bfg1 #cce ,high pot5tial1 #bfh ,h9ts on managem5t ( project+ arcs1 #eb ,hiss+ voltage ( arc1 #bi ,illum9ation1 #bfi ,illusions1 optical1 #aee ,dissolv+ liv+ pictures1 #aeg ,face 9 cl\ds1 #afa ,figure float+ 9 air1 #aeg ,head re/+ on table1 #afj ,head susp5d$ 9 air1 #aeh ,magic cab9et1 #aei ,( motion1 #ee ,multiplication ( images1 #afj ,trick mirror1 #afj ,see+ ?r\gh a brick1 #afa ,image inv]sion1 by l5s1 #add ,by p9 hole1 #abc ,by prism1 #aea ,inc&esc5t lamps1 #bfi ,index ( refraction1 #ach ,inspect+ films1 #aje ,inspect+ ma*9e1 #ig ,inspection memor&a1 #aab ,insulat+ jo9ts1 #bgb ,int]ior conduit1 #bdb ,int]mitt5t sprocket1 #fb1 #ge ,inv]sion ( images1 #abc1 #add1 #aea ,inv]t$ light+1 #bgc ,iris1 !1 #abd ,jo9ts1 #bgc ,junction boxes1 #bge ,k9emacolor process1 #ei ,l5s lamp1 #bd ,l5ses1 conjugate foci (1 #adc ,d\ble concave1 #ade ,d\ble convex1 #ada1 #adb ,focal l5g? (1 #adb ,heat+ (1 #dj ,inv]sion ( image by1 #add ,measur+ focal l5g?1 #di ,objective1 #adi ,pr9cipal focus (1 #adb ,selection (1 #df ,tables (1 #dg1 #dh ,types (1 #adf ,life haz>d1 #ac ,light1 #aac ,infra r$ rays (1 #aag ,int5sity (1 #abj ,int]f]5ce (1 #abj ,law ( inv]se squ>es1 #aba ,reflection (1 #aba1 #abg ,re-composition (1 #aah1 #adh ,s\rce be/ = projection1 #ci ,ultra violet rays (1 #aag ,vibratory1 !ory (1 #aad ,wa/e (1 9 projection1 #de ,wave l5g?s1 #aaf ,ligh?\se effect1 #ccf ,lightn+1 #ccf ,lobby1 #bge ,l[] fe$ loop1 #fb1 #gi ,l[] magaz9e1 #fb ,l[] /eady fe$ sprocket1 #fb1 #gi ,lugs1 #bge1 #cch ,magnify+ glass1 #ade ,metal mold+1 #bgf ,met]s1 #bgh ,met] read+1 #bgi ,mirrors1 #abh ,concave1 #acb ,convex1 #acb1 #ace ,conjugate foci (1 #acc ,pr9cipal focus (1 #acc ,moon boxes1 #cci ,moonlight on wat]1 #cdj ,motiograph motion head1 #he ,motion pictures1 #ee ,motion picture ma*9e1 #fb ,diagram (1 #fc ,discussion ( p>ts (1 #ff ,ge>+ (1 #fe ,motors1 #bha ,op]ation (1 #bad ,/>t+ boxes =1 #bae ,musical acts1 #cdj ,musical bells1 #cda ,music /&s1 #bhe ,objective l5ses1 #adi ,ohm's law1 #cec ,oil+ ma*9e1 #ih ,oil lamps1 imitation (1 #cda ,op5 "w1 #bhf ,op]a glass1 #aej ,op]at+ room1 #agb ,color (1 #ahj ,con/ruction (1 #agf ,entrance & exit1 #agg ,equipm5t (1 #agf ,fire %utt]s =1 #aha ,floor (1 #agh1 #agi ,%utt]1 /r+s =1 #ahc ,tools =1 #ahe ,v5tilation (1 #agf ,wir+ =1 #ahf1 #ahi ,op]ation ( motors1 #bad ,op]ation ( motion picture ma*9es1 #if ,optical illusions1 #aee ,optical in/rum5ts1 #adg ,optical sy/em ( project+ arcs1 #ch ,panel bo>ds1 #bhf ,pa9t bridge1 #bia ,pa9t room1 #bia ,p]si/5ce ( vision1 #ef1 #abd 8,p9 cross0 movem5t1 #gg1 #gh ,p9 plug connectors1 #cda ,plano-concave l5s1 #adf ,plano-convex l5s1 #adf ,plugg+ boxes1 #cdc ,portable /age equipm5t1 #caa ,p[]s motion head1 #hf ,press] roll]s1 #fi ,pr9ciples ( vision1 #abb ,prisms1 #aag1 #aah1 #ada1 #adg1 #aea ,program bo>d1 #bia ,projection1 #ca ,project+ arc lamps1 #ch1 #eb ,prosc5ium side lights1 #afg1 #bid ,reactances1 #aic ,read+ glass1 #add1 #ade ,reflection1 #abf ,inv]sion ( image by1 #abi1 #acj ,multiplication ( image by1 #acj1 #aca ,refraction1 #acg ,critical angle (1 #adj ,index (1 #ach ,pa?s ( rays ( light1 #aci ,refraction & reflection comb9$1 #adj ,retir+ rooms1 #bie ,resi/ance1 #aij ,resuscitation1 #ae ,revolv+ %utt]1 #fb1 #gb1 #aja ,sett+ (1 #ge ,rew9d+1 #ajh ,rheo/ats1 #bie1 #cde ,rigg+ l(t1 #afh ,sciopticon1 #cac ,scre5s1 #agc ,signals1 #big ,signs1 #big ,size ( picture1 #ch ,simplex motion head1 #hg ,slides1 #aji ,sockets1 #bih ,sol> spectrum1 #aah ,spectrum analysis1 #aah ,sph]ical ab]ration1 #ea ,spot on gate1 size (1 #da ,/age cable1 #bih1 #cdg ,/age flues1 #bii ,/age1 plan (1 #afg ,pockets1 #afh1 #cjj ,swit*bo>d1 #afg1 #cje ,/]eopticon lamps1 #cad ,/]eoscope1 reflect+1 #aea ,refract+1 #aea ,/rips1 #cdh ,sunrise1 #cej ,swit* bo>d1 #afg ,swit*es1 #cja1 #cej ,knife1 #cja ,spac+s (1 #bhi ,?ree way1 #cjb ,table ( amp]age = projection1 #dd ,capacity ( bus-b>s1 #bce ,capacity ( wires1 #bch ,drop due to #f amp]es1 #bcc ,fuse spac+s1 #bhi ,motion picture l5ses1 #dg ,( multiple reflections1 #acb ,panel bo>d spac+s1 #bhg ,size ( wire = motors1 #bhd ,/]eopticon l5ses1 #dh ,wa/e ( en]gy by resi/ance1 #aia ,table lamps1 #cea ,take up1 #fb1 #gi1 #ajc1 #ajd ,telescope1 #aej ,t5sion spr+s1 #fb1 #gj1 #ajc ,te/+ arc lamps1 #bh ,c>bons1 #bh1 #bi ,fire traps1 #fh ,!at] build+s1 #afc ,= motion pictures1 #aga ,wir+ (1 #bah ,?ree-wire sy/em1 #aj ,"t beat]s1 #ceb ,tools = op]at+ motion picture ma*9e1 #if ,trans=m]s1 #aid ,trick mirror1 #afj ,two-wire sy/em1 #i ,upp] fe$ reel1 #ff ,upp] loop1 #fb1 #fi ,upp] magaz9e1 #fb1 #ff1 #ig ,upp] /eady fe$ sprocket1 #fb1 #fh ,useful light ( project+ arc1 #dj ,v5tilat+ flues1 #agh ,vision1 p]si/5ce (1 #ef ,visitors1 #aaj ,wat] falls1 #ceb ,wat]pro( film1 #ij ,wire sy/ems1 #i ,books ,t ,really ,tea* y ! 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,,r$ ,,book ,,s]ies ,,( ,,trade ,,s*ool ,,manuals ,by ,f4 ,maire #af mo41 ,clo?1 ,illu/rat$4 ,price1 ea*1 #j4fj ,ext]ior ,pa9t+1 ,wood1 ,iron & ,brick4 ,int]ior ,pa9t+1 ,wat] & ,oil ,colors4 ,colors1 ,:at ,!y ,are & ,:at to ,expect f ,!m4 ,gra9+ & ,m>bl+4 ,c>riage ,pa9t+4 ,! ,wood ,f9i%]4 ,,! ,,automobile ,,h&-,,book ,,ov] #bjj1jjj ,,sold ,by ,,elliott ,,brookes1 ,assi/$ by ,o!r ,well-,kn[n ,exp]ts ,revis$ & ,enl>g$ ,new ,edition--,! l>ge/ & mo/ practical "w publi%$4 ,us$ by all up-to-date automobile s*ools z _! e-day text-book4 ov] #gbj pages & ov] #cbi illu/rations4 ,full ,lea!r ,limp1 ,r\nd ,corn]s1 ,r$ ,edges4 ,price1 #b4jj4 ,illu/ration ,at ! pres5t "t ne>ly all automobile tr\bles or breakd[ns may1 9 almo/ e case1 be trac$ to ! lack ( k or c>elessness ( ! own] or op]ator ( ! c>1 r ?an to ! c> itself4 ,! automobile h& book is a "w ( practical in=mation = ! use ( own]s1 op]ators & automobile me*anics1 giv+ full & concise in=mation on all que/ions relat+ to ! con/ruction1 c>e & op]ation ( gasol9e & electric automobiles1 includ+ road tr\bles1 motor tr\bles1 c>buretor tr\bles1 ignition tr\bles1 batt]y tr\bles1 clut* tr\bles1 />t+ tr\bles4 ,) num]\s tables1 useful rules & =mul1 wir+ diagrams & ov] #cbi illu/rations4 ,special ef=ts h be5 put =? to treat ! subjects ( ignition1 & ignition devices1 9 a mann] befitt+ _! importance4 ,a l>ge section has be5 devot$ to ^! subjects1 includ+ batt]ies1 prim>y & second>y1 magnetos1 c>burators1 sp>k plugs1 & 9 fact all devices us$ 9 connection ) ! production ( ! sp>k4 ,p[] transmission is ?or\ghly discuss$1 & ! v>i\s sy/ems ( transmitt+ ! p[] f ! motor to ! driv+ axle are analyz$ & comp>$4 ,! p]usal ( ?is "w = a few m9utes :5 tr\bles occur1 w (t5 n only save "t1 money1 & worry1 b give great] confid5ce 9 ! c>1 ) reg>d to its go+ qualities on ! road1 :5 prop]ly & intellig5tly c>$ =4 ,a ,,^w ,,to ,,! ,,wise ,! "t is at h& :5 any p]son c>+ = & op]at+ any k9d ( self-propell+ vehicle 9 a public or private capacity1 w h to und]go a rigid exam9ation be=e a /ate bo>d ( exam9]s & secure a lic5se be=e !y c collect _! sal>y or get employm5t4 ,already ,new ,york ,/ate has enact$ su* a law & be=e long1 ) a positive c]ta9ty e /ate 9 ! ,union w pass su* an ord9ance = ! protection ( life & prop]ty4 ,rememb] ?is is a br& new book f cov] to cov]1 j f ! press--,new ,edition--& mu/ n be conf\nd$ ) any =m] editions ( ?is popul> "w4 ,s5t prepaid to any address ^u receipt ( price ,,fr$]ick ,j4 ,,drake ,,co41 ,publi%]s #acbe ,mi*igan ,av5ue ,,*icago1 ,u4 ,s4 ,a4 ,,complete ,,exam9ation ,,que/ions ,,& ,,answ]s ,,= ,,m>9e ,,& ,,/ation>y ,,eng9e]s ,by ,calv9 ,f4 ,sw+le1 ,m4 ,e4 ,au?or ( ,sw+le's ,tw5tie? ,c5tury ,h& ,book = ,/eam ,eng9e]s & ,electricians4 ,mod]n ,locomotive ,eng9e]+ ,h&y ,book1 & ,/eam ,boil]s--,_! con/ruction1 c>e & managem5t ,illu/ration ,?is book is a comp5dium ( useful k1 & practical po9t]s1 = all eng9e]s1 :e!r 9 ! m>9e1 or /ation>y s]vice4 ,= busy m5 & = ^? :o are n incl9$ to sp5d any m "t at /udy ?an is absolutely necess>y1 ! book w prove a ri* m9e f :i* !y may draw nuggets ( j ! k9d ( in=mation t !y are look+ =4 ,! me?od pursu$ by ! au?or 9 ! compilation ( ! "w & 9 ! arrangem5t ( ! subject matt]1 is su* t a man 9 se>* ( any p>ticul> item ( in=mation relative to ! op]ation ( 8 /eam or electric plant1 w exp]i5ce no tr\ble 9 f9d+ t p>ticul> item1 & he w n be "u ! necessity ( go+ ov] a c\ple ( hundr$ pages1 ei!r1 be=e he f9ds x because ! matt] is sy/ematically arrang$ & classifi$4 ,! book w be a valuable addition to any eng9e]'s libr>y1 n alone z a conv5i5t ref]5ce book1 b also z a book = /udy4 ,x also conta9s a complete *apt] on refrig]ation = eng9e]s4 #cfg pages fully illu/rat$1 durably b\nd 9 full ,p]sian ,morocco limp1 r\nd corn]s1 r$ edges4 ,,price #a4ej ,sold by ,booksell]s g5]ally or s5t po/paid to any address ^u receipt ( price by ! ,publi%]s ,,fr$]ick ,j4 ,,drake ,,co4 ,,*icago4 ,u4 ,s4 ,a4 ,transcrib]'s ,notes3 ,! /ructure ( ! pr9t$ book reg>d+ head+s1 sections & 7sub-7sub-sections 0 inconsi/5t & occasionally uncle>4 ,z a consequ5ce1 !re are "s sub-sub-sections t are n "p ( sub-sections 7= example1 sub-sub-section national code rules = gr\nd+1 :]e !re is no sub-section gr\nd+71 & 9-l9e section head]s are n m>k$ z su*4 ,inconsi/5t spac+ ( abbreviations1 capitalisation1 spell+ & hyph5ation h be5 reta9$4 ,! alphabetic ord] ( sections 9 ,*apt]s ,,xviii & ,,xix is n always correct1 ?is has n be5 *ang$4 ,on v>i\s pages !re are ref]5ces to o!r sections & rules ( ! ,national ,electric ,code4 ,^! sections & rules are n li/$ z su*1 & x is !re=e uncle> :e!r ! section or rule ref]r$ to is giv5 9 ?is "w4 ,page #cai3 444 :i* %\ld be us$ to ! p9-plug connector 4443 !re is probably a ^w miss+ 78connect0 or simil>74 ,adv]tisem5t ,automobile ,h&-,book1 444 ov] #gbj pages3 !re is probably a ^w miss+4 ,*anges made ,illu/rations h be5 mov$ out ( p>agraphs1 footnotes h be5 mov$ to directly bel[ ! p>agraph !y ref] to4 ,obvi\s m9or typographical & punctuation errors h be5 correct$ sil5tly4 ,o!r *anges3 ,page #aj3 444 lights turn$ on 444 *ang$ to 444 lights be turn$ on 444 ,page #be1 footnote3 au?or's *ang$ to au?ors' ,page #bf3 misplac$ l9e mov$ to prop] place on page ,page #aic3 au?or's *ang$ to au?ors' ,page #ee3 ap]ature *ang$ to ap]ture 7#bx7 ,page #bji3 8,y0 *ang$ to ,y z o!r ref]5ce lett]s ,page #bch1 la/ r[1 column #be-,watt1 #aaj ,v43 #gdcj *ang$ to #cgdj ,page #cgc3 misplac$ l9e mov$ to prop] place on page4