,?is file 0 produc$ f page images at ! ,int]net ,ar*ive4 ,transcrib]'s ,note ,?is book 0 transcrib$ f scans ( ! orig9al f\nd at ! ,int]net ,ar*ive4 ,tables are repres5t$ z images4 ,! index ( ! orig9al book has be5 remov$1 b ! catalog ( books f ! publi%] has be5 includ$4 ,!re 0 no book cov] image 9 ! scans s ,i creat$ "o4 ,illu/ration3 ,frontispiece4 99,plate ,i4 ,electrical ,conv5tions499 ,,wireless ,,telegraph ,,con/ruction ,,= ,,amateurs ,,by ,,alfr$ ,,p[ell ,,morgan ,,editor ,,me*anical ,,& ,,electrical ,,dep>tm5t ,,( ,,! ,,boys' ,,magaz9e ,,au?or ,,( ,,wireless ,,telegraphy ,,& ,,telephony ,,) #afg ,,illu/rations 99,?ird ,edition1 ,revis$ & ,enl>g$99 ,,) ,a ,,complete ,,description ,,( ,,! ,,new ,,wireless ,,law ,,new ,,york3 ,d4 ,,van ,,no/r& ,,company #be ,,p>k ,,place #aiad ,copyright1 #aiaj1 #aiac1 by ,d4 ,,van ,,no/r& ,,company ,/anhope ,press ,f4 ,h4 ,,gilson ,,company ,,bo/on4 ,u4,s4,a4 ,,preface4 ,9 ?is "w1 ! au?or has endeavor$ to pres5t a book embrac+ practical in=mation = ^? :o may wi% to build = private or exp]im5tal use a set ( wireless in/rum5ts :i* are m ?an toys b yet n s exp5sive z ! comm]cial app>atus4 ,_m books h be5 publi%$ on ! subject ( wireless telegraphy1 b 9 !m ! int]e/s ( ! novice h be5 r neglect$ & 9 ord] to build an outfit he has be5 =c$ to rely ^u a s]ies ( disconnect$ articles publi%$ 9 ! amateur p]iodicals4 ,x is ! object ( ?is book to %[ ! con/ruction ( simple1 effici5t in/rum5ts by means ( cle> draw+s1 & to give en\gh elem5t>y !ory & practical h9ts to enable ! exp]im5t] to build a size & type 9 keep+ ) 8 ne$s & res\rces4 ,! tiresome h[ to make /yle has be5 avoid$ z f> z possible4 ,hi/ory & all unimportant details are omitt$ to give 9 _! place a concise explanation ( ! p>ts play$ by ! diff]5t in/rum5ts & ! influ5ce ( develop+ _! v>i\s factors4 ,a small la! & a set ( taps & dies are necess>y to produce app>atus hav+ a good appe>ance1 b a little +5uity display$ 9 adapt+ screws & p>ts ( old electrical in/rum5ts (t5times at h& w make ^! tools unnecess>y4 ,ord9>y precaution & pl5ty ( "t %\ld be us$ 9 ! "w4 ,x is obvi\s t if a l>ge coil is to be made1 x is well to insure its successful completion by pa9/ak+ c>e & ! use ( prop] mat]ials4 ,nei!r is x wise to /ra9 an in/rum5t ?r\gh becom+ impati5t & us+ x be=e x is prop]ly complet$ & adju/$4 ,:]ev] possible in/ructions h be5 giv5 reg>d+ ! adju/m5t ( ! app>atus1 b x is only by actual practice t ! op]ator w acqua9t himself ) ! mo/ effici5t manipulation4 ,extracts f articles contribut$ by ! ,au?or to ,popul> ,electricity h be5 us$ 9 ! *apt]s on ,sp>k ,gaps1 ,oscillation ,detectors & ,telephone ,receiv]s1 ?r\gh ! c\rtesy ( ! editor1 ,mr4 ,h4 ,w4 ,"y4 ,9 conclusion1 ! writ] wi%es to express 8 ?anks to ! ,unit$ ,wireless ,telegraph ,company = views ( _! app>atus & to ! o!r firms :o h loan$ electrotypes & suppli$ in=mation4 ,to ^? :o h assi/$ 9 ! prep>ation ( ! book1 m especially to ,mr4 ,saf=d ,adams1 = num]\s sugge/ions & criticisms1 ! ,au?or desires to express 8 full ackn[l$gm5ts4 ,,alfr$ ,,p[ell ,,morgan4 ,,upp] ,,montclair1 ,n4,j4 ,june1 #aiaj4 ,,preface ,,to ,,! ,,?ird ,,edition4 ,! success ( ! previ\s editions ( ?is book has made a new & ?ird "o necess>y4 ,!re h n be5 any />tl+ *anges or new discov]ies made 9 ! field ( wireless telegraphy s9ce ! fir/ edition 0 publi%$1 b ! art has und]gone a numb] ( small *anges & improvem5ts :i* h increas$ ! effici5cy & selectivity ( ! app>atus4 ,s9ce !n a f$]al law re/rict+ & controll+ wireless telegraphy has be5 pass$4 ,its effect has be5 to place wireless telegraphy ^u a m c]ta9 basis1 & to give a recogniz$ /&+ to ! amateur exp]im5t]4 ,?is new law has be5 includ$ 9 ?is edition 9 ! =m ( an app5dix4 ,! amateur w d well to read x c>efully4 ,compliance ) its regulations w prove b5eficial r ?an a h9drance4 ,a fully illu/rat$ *apt] expla9+ exactly h[ to comply ) ! law & h[ to build ! app>atus requir$ has be5 add$4 ,complete descriptions ( sev]al new types ( detectors are also includ$4 ,all old matt] has be5 ?or\ghly revis$ & sev]al illu/rations replac$ by ones m up-to-date & ( direct int]e/4 ,,alfr$ ,p4 ,,morgan4 ,,upp] ,,montclair1 ,n4,j4 ,may1 #aiac4 ,,preface4 4444444444444444444444444444444444444444 444444444444444444 ,,preface ,,to ,,! ,,?ird ,,edition4 4444444444444444444444444444444444444 ,,*apt] ,i4 ,,introductory4 4444444444444444444444444444444444444444 44 ,! ,transmission & ,reception ( ,electric ,waves4 444444444444444 ,,*apt] ,,ii4 ,,! ,,app>atus4 4444444444444444444444444444444444444444 ,,*apt] ,,iii4 ,,a]ials ,,& ,,e>? ,,connections4 44444444444444444444444 ,,*apt] ,,iv4 ,,induction ,,coils4 44444444444444444444444444444444444444 ,,*apt] ,v4 ,,int]rupt]s4 4444444444444444444444444444444444444444 44 ,,*apt] ,,vi4 ,,trans=m]s4 4444444444444444444444444444444444444444 4 ,con/ruction ( a #b-,k4,w4 ,trans=m]4 444444444444444444444444444 ,,*apt] ,,vii4 ,,oscillation ,,cond5s]s ,,& ,,leyd5 ,,j>s4 44444444444444 ,,*apt] ,,viii4 ,,sp>k ,,gaps ,,or ,,oscillators4 44444444444444444444444444 ,,*apt] ,,ix4 ,,transmitt+ ,,helixes4 444444444444444444444444444444444 ,,*apt] ,x4 ,,keys4 4444444444444444444444444444444444444444 4444444444 ,,*apt] ,,xi4 ,,a]ial ,,swit*es ,,& ,,an*or ,,gaps4 4444444444444444444444 ,,*apt] ,,xii4 ,,hot ,,wire ,,ammet]4 444444444444444444444444444444444444 ,,*apt] ,,xiii4 ,,oscillation ,,detectors4 444444444444444444444444444444 ,,univ]sal ,,detector4 4444444444444444444444444444444444444444 444 ,,electrolytic ,,detectors4 4444444444444444444444444444444444444444 4 ,,tantalum ,,detector4 4444444444444444444444444444444444444444 444444 ,,cry/al ,,detectors4 4444444444444444444444444444444444444444 444444 ,,lead ,,p]oxide ,,detector4 4444444444444444444444444444444444444444 4 ,,! ,,m>coni ,,magnetic ,,detector4 4444444444444444444444444444444444 ,,*apt] ,,xiv4 ,,tun+ ,,coils ,,& ,,trans=m]s4 44444444444444444444444 ,,*apt] ,,xv4 ,,receiv+ ,,cond5s]s4 444444444444444444444444444444444 ,,*apt] ,,xvi4 ,,telephone ,,receiv]s ,,& ,,headb&s4 4444444444444444444 ,,*apt] ,,xvii4 ,,op]ation4 4444444444444444444444444444444444444444 44 ,,electrical ,,t]ms ,,& ,,def9itions4 4444444444444444444444444444444 ,,*apt] ,,xviii4 ,,! ,,amateur ,,& ,,! ,,wireless ,,law4 ,,:at ,,x ,,is2 ,,h[ ,,to ,,comply2 ,,h[ ,,to ,,secure ,a ,,lic5se4 4444444444444444444444444444444444 ,,app>atus ,,requir$ ,,9 ,,_m ,,in/ances ,,9 ,,ord] ,,to ,,comply ,,) ,,! ,,wireless ,,law4 4444444444444444444444444444444444444444 44444444444 ,receiv+ ,app>atus4 4444444444444444444444444444444444444444 4444 ,frontispiece4 99,plate ,i4 ,electrical ,conv5tions499 4444444444444444 ,fig #a4 ,h]tz ,oscillator & ,resonator4 4444444444444444444444444444 ,fig4 #b4 ,hydraulic ,oscillator4 4444444444444444444444444444444444444 ,fig4 #c4 ,hydraulic ,transmitt] & ,receptor4 444444444444444444444 ,fig4 #d4 ,simple ,wireless ,telegraph ,transmitt] & ,receptor4 4444444 ,fig4 #e4 ,electric ,waves & ,l9es ( ,/ra94 44444444444444444444444 ,fig4 #f4 ,resonance ,tube4 4444444444444444444444444444444444444444 444 ,fig4 #g4 ,lag & ,lead4 4444444444444444444444444444444444444444 44444 ,fig4 #h4 ,tun$ ,hydraulic ,transmitt] & ,receptor4 44444444444444444 ,fig4 #i4 ,tun$ ,wireless ,telegraph ,transmitt] & ,receptor 444444444 ,fig4 #aj4 ,long-di/ance ,receiv+ ,set4 44444444444444444444444444444 ,fig4 #aa4 ,murdock ,receiv+ ,set4 44444444444444444444444444444444444 ,fig4 #ab4 ,clapp-,ea/ham ,receiv+ ,set4 44444444444444444444444444444 ,fig4 #ac4 ,prague ,receiv+ ,set4 444444444444444444444444444444444444 ,fig4 #ad4 ,receiv+ ,set4 4444444444444444444444444444444444444444 444 ,fig4 #ae4 ,receiv+ ,set4 4444444444444444444444444444444444444444 444 ,fig4 #af4 ,murdock ,transmitt+ & ,receiv+ ,set4 444444444444444444 ,fig4 #ag4 ,unit$ ,wireless ,portable ,outfit4 4444444444444444444444444 99,plate ,,ii4 ,a]ial ,sy/ems499 444444444444444444444444444444444444444 ,fig4 #ah4 ,electrose ,insulators4 444444444444444444444444444444444444 ,fig4 #ai4 ,guy ,insulator4 4444444444444444444444444444444444444444 444 ,fig4 #bj4 ,insulat+ ,tube4 4444444444444444444444444444444444444444 4 ,fig4 #ba4 ,high-t5sion ,cable & ,insulator4 444444444444444444444444 ,fig4 #bb4 ,flat-top ,t ,a]ial4 444444444444444444444444444444444444444 ,fig4 #bc4 ,gr\nd ,clamp4 4444444444444444444444444444444444444444 4444 ,fig4 #bd4 ,swit* = ,lightn+ ,protection4 4444444444444444444444444 ,fig4 #be4 ,diagram ( an ,induction ,coil4 4444444444444444444444444444 ,fig4 #bf4 ,induction ,coil ,core4 4444444444444444444444444444444444444 ,fig4 #bg4 ,!oretical & practical =m ( second>y4 4444444444444 ,fig4 #bh4 ,lay] ,w9d+ = ,small ,coils4 444444444444444444444444444 ,fig4 #bi4 ,section ,w9d]4 4444444444444444444444444444444444444444 44 ,fig4 #cj4 ,impregnator = ,silk ,cov]$ ,wire4 44444444444444444444444 ,fig4 #ca4 ,me?ods ( ,connect+ ! ,second>y ,sections4 444444444444 ,fig4 #cb4 ,coil ,case4 4444444444444444444444444444444444444444 4444444 ,fig4 #cc4 ,simple ,int]rupt]4 44444444444444444444444444444444444444 ,fig4 #cd4 ,indep5d5t ,int]rupt]4 444444444444444444444444444444444 ,fig4 #ce4 ,details ( ,magnets4 44444444444444444444444444444444444444 ,fig4 #cf4 ,details ( ,mov+ ,p>ts4 444444444444444444444444444444444 ,fig4 #cg4 ,details ( ,/&>d & ,screws4 44444444444444444444444444 ,fig4 #ch4 ,diagram ( ,connections = an ,indep5d5t ,int]rupt]4 444 ,fig4 #ci4 ,con/ruction ( a ,pap] ,cond5s]4 44444444444444444444444 ,fig4 #dj4 ,w5helt & ,simon ,electrolytic ,int]rupt]s4 4444444444444 ,fig4 #da4 ,con/ruction ( ,electrolytic ,int]rupt]s4 444444444444444 ,fig4 #db4 ,details ( ,electrolytic ,int]rupt]s4 44444444444444444444 ,fig4 #dc4 ,electrolytic ,int]rupt]4 44444444444444444444444444444444 ,fig4 #dd4 ,assembly & ,dim5sions ( ,core4 4444444444444444444444444 ,fig4 #de4 ,fib] ,head & ,sep>ator4 44444444444444444444444444444444 ,fig4 #df4 ,section ,=m4 4444444444444444444444444444444444444444 4444 ,fig4 #dg4 ,me?ods ( ,connect+ ,sections4 44444444444444444444444444 ,fig4 #dh4 ,assembly ( ,leg4 4444444444444444444444444444444444444444 4 ,fig4 #di4 ,trans=m] ) ,"o ,second>y remov$4 444444444444444444 ,fig4 #ej4 ,wir+ ,diagram4 4444444444444444444444444444444444444444 44 ,fig4 #ea4 ,clapp-,ea/ham #a_/d-,k4,w4 ,trans=m]4 4444444444444444444444 ,fig4 #eb4 ,unit$ ,wireless ,motor-,g5]ator set = supply+ ,alt]nat+ ,curr5t to ! ,trans=m]4 444444444444444444444444444 ,fig4 #ec4 ,simple ,cond5s]4 4444444444444444444444444444444444444444 ,fig4 #ed4 ,leyd5 ,j>4 4444444444444444444444444444444444444444 444444 ,fig4 #ee4 ,a]ial ,swit*4 4444444444444444444444444444444444444444 4 ,fig4 #ef4 ,amco ,oscillation ,cond5s]4 444444444444444444444444444444 ,fig4 #eg4 ,clapp-,ea/ham ,oscillation ,cond5s]4 444444444444444444444 ,fig4 #eh4 ,me?ods ( ,v>y+ ,capacity4 44444444444444444444444444444 ,fig4 #ei4 ,sp>k ,gaps4 4444444444444444444444444444444444444444 444444 ,fig4 #fj4 ,sp>k ,gap4 4444444444444444444444444444444444444444 4444444 ,fig4 #fa4 ,closely ,c\pl$ ,helix4 44444444444444444444444444444444444 99,plate ,,iii4 ,transmitt+ ,circuits499 4444444444444444444444444444444 ,fig4 #fb4 ,prague ,transmitt+ ,helix4 4444444444444444444444444444444 ,fig4 #fc4 ,closely ,c\pl$ ,tun+ ,circuit4 44444444444444444444444444 ,fig4 #fd4 ,loosely ,c\pl$ ,transmitt+ ,helix & ,contact ,clip4 44444 ,fig4 #fe4 ,loosely ,c\pl$ ,transmitt+ ,circuit4 44444444444444444444 ,fig4 #ff4 ,unit$ ,wireless ,helix1 ,sp>k ,gap & ,cond5s]4 4444444444 ,fig4 #fg4 ,morse ,key fitt$ ) ,ext5sion ,lev]4 4444444444444444444 ,fig4 #fh4 ,wireless ,key4 4444444444444444444444444444444444444444 4444 ,fig4 #fi4 ,unit$ ,wireless ,type ,key4 444444444444444444444444444444 ,fig4 #gj4 ,connections = ,a]ial ,swit*4 444444444444444444444444444 ,fig4 #ga4 ,a]ial ,swit*es4 4444444444444444444444444444444444444444 4 ,fig4 #gb4 ,detail ( ,contacts4 44444444444444444444444444444444444444 ,fig4 #gc4 ,details ( ,swit* ,p>ts4 444444444444444444444444444444444 ,fig4 #gd4 ,me?od ( ,fa/5+ ,knife4 4444444444444444444444444444444 ,fig4 #ge4 ,t ,a]ial ,swit*4 444444444444444444444444444444444444444 ,fig4 #gf4 ,unit$ ,wireless ,lightn+ ,swit*4 4444444444444444444444 ,fig4 #gg4 ,%oemak] ,tun+ ,coil & ,a]ial ,swit*4 44444444444444444 ,fig4 #gh4 ,unit$ ,wireless ,an*or ,gaps4 444444444444444444444444444 ,fig4 #gi4 ,an*or ,gap4 4444444444444444444444444444444444444444 444444 ,fig4 #hj4 ,simple ,hot ,wire ,met]4 44444444444444444444444444444444444 ,fig4 #ha4 ,met] ) ,case ,remov$4 444444444444444444444444444444444 ,fig4 #hb4 ,glass ,comp5sat+ ,/rip4 44444444444444444444444444444444 ,fig4 #hc4 ,details ( ,hot ,wire ,supports4 44444444444444444444444444 ,fig4 #hd4 ,details ( ,movem5t4 4444444444444444444444444444444444444 ,fig4 #he4 ,complete ,movem5t4 444444444444444444444444444444444444444 ,fig4 #hf4 ,side ,view ( ,hot ,wire & ,movem5t4 4444444444444444444444 ,fig4 #hg4 ,unit$ ,wireless ,hot ,wire ,ammet]4 444444444444444444444444 ,fig4 #hh4 ,univ]sal ,detector4 44444444444444444444444444444444444444 ,fig4 #hi4 ,details ( ,univ]sal ,detector4 444444444444444444444444444 ,fig4 #ij4 ,p>ts ( ,univ]sal ,detector4 44444444444444444444444444444 ,fig4 #ia4 ,b>e ,po9t ,electrolytic ,detector4 444444444444444444444444 ,fig4 #ib4 ,effect ( ,expos+ too mu* ,wire4 444444444444444444444444 ,fig4 #ic4 ,electrolytic ,detector ,circuits4 44444444444444444444444444 ,fig4 #id4 ,electrolytic ,detector4 44444444444444444444444444444444444 ,fig4 #ie4 ,=m+ ,glass ,po9t4 44444444444444444444444444444444444 ,fig4 #if4 ,%oemak] ,detector4 44444444444444444444444444444444444444 ,fig4 #ig4 ,%oemak] ,detector ,circuits4 44444444444444444444444444444 ,fig4 #ih4 ,lamp ,detector4 4444444444444444444444444444444444444444 444 ,fig4 #ii4 ,simple ,electrolytic ,detector4 4444444444444444444444444444 ,fig4 #ajj4 ,electrolytic ,detector4 4444444444444444444444444444444444 ,fig4 #aja4 ,details ( ,electrolytic ,detector4 44444444444444444444444 ,fig4 #ajb4 ,increas+ ! ,s5sitiv5ess ( an ,electrolytic ,detector4 ,fig4 #ajc4 ,tantalum ,detector4 44444444444444444444444444444444444444 ,fig4 #ajd4 ,unit$ ,wireless ,c>borundum ,detector 7horizontal type74 4 ,fig4 #aje4 ,unit$ ,wireless ,c>borundum ,detector 7v]tical type74 444 ,fig4 #ajf4 ,clapp-,ea/ham ,f]ron ,detector4 44444444444444444444444444 ,fig4 #ajg4 ,silicon ,cry/al 9 ,cup4 444444444444444444444444444444444 ,fig4 #ajh4 ,silicon ,detector ,circuits4 444444444444444444444444444444 ,fig4 #aji4 ,p]ikon ,detector ,elem5ts4 444444444444444444444444444444 ,fig4 #aaj4 ,p]ikon ,detector4 444444444444444444444444444444444444444 ,fig4 #aaa4 ,p]oxide ( ,lead ,detector4 444444444444444444444444444444 ,fig4 #aab4 ,m>coni ,magnetic ,detector4 444444444444444444444444444444 ,fig4 #aac4 ,details ( ,trans=m]4 444444444444444444444444444444444 ,fig4 #aad4 ,me?od ( ,jo9+ ,ends ( ,b&4 4444444444444444444444444 ,fig4 #aae4 ,pulley4 4444444444444444444444444444444444444444 444444444 ,fig4 #aaf4 ,pulley ,be>+s4 4444444444444444444444444444444444444444 ,fig4 #aag4 ,circuit ( ,magnetic ,detector4 444444444444444444444444444 ,fig4 #aah4 ,flem+ ,oscillation ,valve4 444444444444444444444444444444 ,fig4 #aai4 ,flame ,audion4 4444444444444444444444444444444444444444 444 ,fig4 #abj4 ,circuit ( ,flame ,audion4 44444444444444444444444444444444 ,fig4 #aba4 ,d\ble-slide ,tun+ ,coil4 4444444444444444444444444444444 ,fig4 #abb4 ,slid]s4 4444444444444444444444444444444444444444 44444444 ,fig4 #abc4 ,d\ble-slide ,tun+ ,coil ,circuits4 4444444444444444444444 99,plate ,,iv4 ,receiv+ ,circuits4 7,/raightaway ,a]ial4799 444444444444 ,fig4 #abd4 ,murdock ,d\ble-slide ,tun+ ,coil4 44444444444444444444444 ,fig4 #abe4 ,unit$ ,wireless ,receiv+ ,set4 44444444444444444444444444 ,fig4 #abf4 ,unit$ ,wireless ,portable ,receiv+ ,set4 44444444444444444 ,fig4 #abg4 ,oscillation ,trans=m]4 44444444444444444444444444444444 ,fig4 #abh4 ,unit$ ,wireless ,receiv+ ,trans=m]4 444444444444444444 ,fig4 #abi4 ,details ( ,receiv+ ,trans=m]4 44444444444444444444444 ,fig4 #acj4 ,slid] = ,loose ,c\pl]4 4444444444444444444444444444444 ,fig4 #aca4 ,loosely ,c\pl$ ,tun+ ,circuits4 444444444444444444444444 ,fig4 #acb4 ,comb9ation ,loosely & ,closely ,c\pl$ ,tun]4 4444444444 ,fig4 #acc4 ,clapp-,ea/ham ,loose ,c\pl]4 4444444444444444444444444444 ,fig4 #acd4 ,a ,highly ,effici5t ,=m ( ,loose ,c\pl]4 444444444444444 ,fig4 #ace4 ,pot5tiomet]4 4444444444444444444444444444444444444444 44 ,fig4 #acf4 ,amco ,pot5tiomet]4 4444444444444444444444444444444444444 99,plate ,v4 ,receiv+ ,circuits499 444444444444444444444444444444444444 ,fig4 #acg4 ,tun+ ,circuit ) & )\t an ,adju/able ,cond5s]4 4 ,fig4 #ach4 ,tubul> ,cond5s]4 44444444444444444444444444444444444444 ,fig4 #aci4 ,v>iable ,cond5s]4 4444444444444444444444444444444444444 ,fig4 #adj4 ,details ( ,v>iable ,cond5s]4 44444444444444444444444444 ,fig4 #ada4 ,slid+ ,plate ,v>iable ,cond5s]4 44444444444444444444444 ,fig4 #adb4 ,types ( ,p]man5t ,magnets4 44444444444444444444444444444 ,fig4 #adc4 ,gr9d+ ,tool4 4444444444444444444444444444444444444444 44 ,fig4 #add4 ,p>ts ( a ,holtz] ,cabot ,receiv]4 4444444444444444444444 ,fig4 #ade4 ,holtz] ,cabot ,head ,set4 444444444444444444444444444444444 ,fig4 #adf4 ,adju/able ,head ,b&4 44444444444444444444444444444444444 ,fig4 #adg4 ,m>coni ,/ation at ,siasconset1 ,mass4 44444444444444444444 99,plate ,,vi4 ,de,forest & ,m>coni ,sy/ems499 4444444444444444444444444 ,fig4 #adh4 ,exp]im5tal ,amateur ,/ation ( ,w4 ,haddon1 ,brooklyn1 ,n4 ,y4 ,fig4 #adi4 ,complete ,receiv+ ,outfit ,consi/+ ( ,receiv+ ,trans=m]1 ,detector1 ,fix$ ,cond5s]1 ,load+ ,coil1 ,two ,v>iable ,cond5s]s1 ,pot5tiomet]1 ,batt]y1 ,swit*es1 etc4 4444444444444444 ,fig4 #aej4 ,receiv+ ,outfit ,consi/+ ( ,receiv+ ,trans=m]1 ,fix$ ,cond5s] & ,detector4 4444444444444444444444444444444444444 ,fig4 #aea4 ,amco ,oscillation ,helix4 444444444444444444444444444444444 ,fig4 #aeb4 ,details ( ,oscillation ,helix ,con/ruction4 44444444444444 ,fig4 #aec4 ,qu5*$ ,gap4 4444444444444444444444444444444444444444 444 ,fig4 #aed4 ,qu5*$ ,gap4 4444444444444444444444444444444444444444 444 ,fig4 #aee4 ,details ( ,disk & ,r+4 4444444444444444444444444444444 ,fig4 #aef4 ,explanatory ,draw+ ( ,qu5*$ ,gap4 44444444444444444444 ,fig4 #aeg4 ,amco ,rot>y ,gap4 4444444444444444444444444444444444444444 ,fig4 #aeh4 ,details ( ,revolv+ ,p>ts ( ,rot>y ,gap4 444444444444444 ,fig4 #aei4 ,details ( ,rot>y ,gap4 4444444444444444444444444444444444 ,fig4 #afj4 ,me?ods ( ,prev5t+ ,kick ,back4 4444444444444444444444 ,fig4 #afa4 ,v>iomet]4 4444444444444444444444444444444444444444 44444 ,fig4 #afb4 ,silicon ,detector4 444444444444444444444444444444444444444 ,fig4 #afc4 ,pyron ,detector4 4444444444444444444444444444444444444444 4 ,fig4 #afd4 ,gal5a ,detector4 4444444444444444444444444444444444444444 ,fig4 #afe4 ,audion4 4444444444444444444444444444444444444444 444444444 ,fig4 #aff4 ,audion ,circuit4 4444444444444444444444444444444444444444 4 ,fig4 #afg4 ,rot>y ,v>iable ,cond5s]4 444444444444444444444444444444 ,,*apt] ,i4 ,,introductory4 ,be+ desir\s ( keep+ ?is book z f> z possible )9 ! limits prescrib$ by ! title1 x is n possible to g deeply into ! !ory ( ! propagation ( electric waves1 b at ! same "t x is n deem$ advisable to plunge sudd5ly into ! con/ruction ( wireless app>atus )\t giv+ "s explanation ( ! und]ly+ pr9ciples4 ,if ! read] desires in=mation ^u ?is subject he is ref]r$ to ,flem+'s ,electric ,wave ,telegraphy or ! same au?or's ,elem5t>y ,manual ( ,radio-telegraphy & ,radio-telephony4 ,! explanations giv5 9 ?is *apt] d n involve any actual !ory ( ! transmission & reception ( electric waves4 ,!y are m]ely int5d$ to %[ ! tra9 ( actions :i* take place & may be obs]v$ 9 a physical s5se4 ,) ?is purpose 9 view1 sev]al ref]5ces h be5 made to simple hydraulic app>atus & an analogy drawn to r5d] ! explanation cle>]4 ,! ,transmission & ,reception ( ,electric ,waves4 ,wireless telegraphy by means ( electromagnetic waves may be divid$ into f\r di/9ct op]ations1 namely3 #a4 ,! g5]ation ( electrical oscillations4 #b4 ,! trans=mation ( electrical oscillations into electrical waves4 #c4 ,! trans=mation ( electrical waves into electrical oscillations4 #d4 ,! detection ( ! electrical oscillations4 ,! fir/ two op]ations comprise ^? tak+ place at ! transmitt]1 :ile ! la/ two1 :i* are ! conv]se ( ! fir/1 are 9 evid5ce only :5 receiv+4 ,illu/ration3 ,fig #a4 ,h]tz ,oscillator & ,resonator4 ,fig4 #a illu/rates ! orig9al ,h]tz oscillator & resonator1 :i* is ! simple/ =m a wireless in/allation may take4 ,t repres5ts ! transmitt+ app>atus & ,r ! receptor4 ,at ! transmitt+ /ation a telegraph key is plac$ 9 s]ies ) a batt]y & an induction coil4 ,two l>ge metal plates1 t & t'1 are connect$ to ! opposite sides ( ! sp>k gap1 :i* 9 turn is connect$ to ! second>y ( ! induction coil4 ,:5 ! key is press$ ! electrical circuit is complet$ & ! voltage ( ! batt]y is rais$ suffici5tly by ! induction coil to *>ge ! metal plates t & t'4 ,! key s]ves to break ! curr5t into p]iods correspond+ to ! dots & da%es ( ! telegraph code4 ,:5 ! high voltage ( ! induction coil is impress$ ^u ! plates !y become *>g$1 & be+ ( opposite pol>ity1 :5 at a maximum ! en]gy ru%es across ! gap & produces a disruptive sp>k4 ,ea* dis*>ge1 al?\gh appe>+ l a s+le sp>k pass+ 9 "o direction1 is 9 reality made up ( a l>ge numb] ( rapid oscillations or surg+s4 ,! fir/ passage ( curr5t s]ves to m ?an dis*>ge ! plates & !y become *>g$ 9 ! opposite direction4 ,a rev]se dis*>ge !n occurs :i* also ov]/eps itself1 & ?us ! oscillations g on1 b gradually become weak] & weak] until !y die completely or are damp$ out4 ,! heat$ air ( ! sp>k gap becomes a conductor dur+ ! passage ( ! sp>k1 & ! oscillations are enabl$ to surge back & =? at ! rate ( #ae1jjj to #a1jjj1jjj p] second1 al?\gh ! actual dis*>ge may take only a fraction ( a second4 ,illu/ration3 ,fig4 #b4 ,hydraulic ,oscillator4 ,! g5]ation ( electrical oscillations may p]haps be made m cle> by ref]5ce to ! hydraulic app>atus illu/rat$ 9 ,fig4 #b4 ,t & ,t' are communicat+ tubes divid$ by an ela/ic membrane ,m4 ,! tubes may be lik5$ to ! metal plates t & t' or ! arms ( ! oscillator4 ,! membrane may be lik5$ to ! lay] ( air betwe5 ! knobs :i* sep>ates ! opposite arms ( ! oscillator4 ,p is a pump connect$ to ! two tubes ,t & ,t'1 & ! brok5 l9es 9 ! app>atus repres5t wat]4 ,! pump corresponds to ! induction coil 9 ,fig4 #a1 & ! wat] to ! second>y curr5ts ( ! induction coil4 ,:5 ! pump is set 9 op]ation1 ! wat] is drawn f ! tube ,t & inject$ into ,t'4 ,! pump valves prev5t x f fl[+ back4 ,:5 ! level becomes v high 9 ,t'1 ! great pressure di/5ds ! membrane 9 ! direction %[n by ! dott$ l9e until f9ally x bur/s & ! wat] is all[$ to fl[ ) a ru% into ! tube ,t4 ,b ! in]tia ( ! wat] causes x to rise high] 9 ! tube ?an its f9al position ( equilibrium1 :ile 9 return+ & endeavor+ to seek its level its in]tia c>ries x bel[ ?is position4 ,?us ! wat] oscillates back & =? until f9ally x comes to re/4 ,simil>ly ! diff]5ce ( pot5tial ( ! oscillator arms is n imm$iately equaliz$ ^u ! break+ d[n ( ! air gap1 & ! app>atus becomes ! seat ( extremely rapid electrical oscillations1 z expla9$ above4 ,all space is suppos$ to be fill$ ) a highly att5uat$1 invisible & weightless m$ium call$ e!r4 ,:5 ! electrical oscillations surge back & =? ?r\gh ! arms ( ! oscillator1 portions ( ! en]gy are ?r[n (f f ! app>atus & travel 9 enl>g+ circles l ! ripples on a pond4 ,^! consi/ ( l9es ( dielectric /ress or electro/atic flux :i* pass ?r\gh ! e!r & con/itute electromagnetic waves4 ,! receptor or resonator ,r1 ,fig4 #a1 consi/s ( a circle ( wire hav+ 9 x a small sp>k gap capable ( m9ute adju/m5t4 ,two metal plates r & r' are sometimes atta*$ to ! opposite sides ( ! sp>k gap4 ,:5 ! key is press$ at ! transmitt+ /ation & waves are s5t out ?r\gh ! e!r1 !y /rike ! resonator & set up !re9 electrical oscillations :i* pass across ! gap 9 ! %ape ( sp>ks4 ,illu/ration3 ,fig4 #c4 ,hydraulic ,transmitt] & ,receptor4 ,to make ! explanation cle>]1 let u consid] ,fig4 #c 9 :i* two floats or blocks ( wood are repres5t$ z re/+ on ! surface ( a tank or pool ( wat]4 ,"o float1 ,a1 is connect$ by a rope & pulley s t by j]k+ ! rope ! float may be made to oscillate & cause little ripples or waves to pass outw>ds 9 a gradually enl>g+ circle4 ,:5 ! waves rea* ! float1 ,b1 !y cause x to rise & fall ) ea* wave or to oscillate & reproduce ! movem5ts ( ! float1 ,a4 ,likewise ! oscillations set up by a wireless transmitt] are s5t out into space to be caught & duplicat$ at ! receiv+ /ation4 ,( c\rse ?is analogy to ! propagation & reception ( electric waves is n ! same z ! true electrical actions1 b is m]ely a graphical1 repres5tation4 ,illu/ration3 ,fig4 #d4 ,simple ,wireless ,telegraph ,transmitt] & ,receptor4 ,! wireless telegraph outfit illu/rat$ 9 ,fig4 #a w\ld n s]ve = m ?an %ort di/ances ( a few feet1 & s a some:at simil> b m effici5t app>atus is employ$ 9 practice4 ,fig4 #d %[s su* a sy/em 9 its simple/ =m4 ,9 ?is case ! second>y or high pot5tial leads ( ! induction coil are connect$1 "o to an e>? & ! o!r to an a]ial or ant5na compos$ ( a numb] ( b>e copp] wires insulat$ & susp5d$ f a ma/4 ,all electrically *>g$ bodies are surr\nd$ by an electro/atic field ( =ce1 ! nature ( :i* 9 !ory is a /ate ( /ra94 ,! action ( an induction coil connect$ z 9 ,fig4 #d is to *>ge ! upp] "p ( ! a]ial above ! sp>k gap1 say ) negative electricity & e/abli% a field ( =ce 9 its vic9ity v>y+ 9 area f a few feet to sev]al miles4 ,:5 ! *>ge rea*es a c]ta9 pot5tial x is suffici5t to puncture ! lay] ( air 9 ! gap & a sp>k takes place1 sett+ up electrical oscillations4 ,illu/ration3 ,fig4 #e4 ,electric ,waves & ,l9es ( ,/ra94 ,previ\s to ! rupture ( ! sp>k gap1 l9es ( electric /ra9 or =ce /ret* f ! a]ial to ! e>? on all sides z 9 ! c5t] ( ,fig4 #e4 ,a l9e ( =ce may be def9$ z a curve drawn 9 ! electric field s t ! direction ( ! curve is ! same z t ( ! electric int5sity at t po9t4 ,! a]ial & ! e>? act l ! two metal plates 9 ,fig4 #a or l ! opposite plates ( a cond5s]4 ,z soon z ! air gap is punctur$ x becomes conductive & ! a]ial *>ge ru%es d[n into ! e>?4 ,) ! dis*>ge1 ! /ra9 9 ! electro/atic field is releas$ & ! a]ial *>ge ru%es d[n into ! e>?1 b 9 s relax+ produces a new curr5t & builds up a /ra9 ar\nd ! ant5na opposite 9 direction to ! fir/4 ,?is process repeats itself v rapidly & electrical oscillations are ?us set up 9 ! ant5na4 ,e oscillation *anges ! direction ( ! magnetic flux or dielectric /ra9 & causes ! imag9>y l9es :i* orig9ally /ret*$ f ! a]ial to ! e>? to be displac$ & ! ends t]m9at+ at ! a]ial to run d[n x & =m semi-loops or inv]t$ ,u's /&+ ) _! ends on ! e>? 9 a circul> ripple ar\nd ! a]ial & mov+ away f x ) ! spe$ ( light4 ,9 ,fig4 #e ?ree oscillations are suppos$ to h tak5 place4 ,! %orte/ di/ance betwe5 two adjac5t po9ts at :i* ! electric /ra9 is at a maximum 9 ! same direction & p]iod ( "t is ! wave l5g? emitt$ by ! a]ial4 ,! sep>ate /&+ gr\ps ( dielectric /ra9 mov+ away f ! ant5na are electromagnetic waves4 ,9 ! figure1 ! adjac5t gr\ps are sep>at$ by half a wave l5g?4 ,^! waves are emitt$ at "r angles to ! transmitt+ a]ial1 :5ce !y pass ?r\gh ! e!r to ! o!r /ation4 ,:5 !y rea* ! receiv+ a]ial !y set up electrical oscillations !re9 :i* are too weak to be p]ceptible 9 ! %ape ( sp>ks z 9 ! orig9al ,h]tz oscillator & resonator because ( ! great di/ance sep>at+ ! /ations1 s !y are made to fl[ ?r\gh a detector1 :i* 9 ,fig4 #d is repres5t$ z be+ a cry/al ( a m9]al call$ silicon4 ,:5 ! high frequ5cy curr5ts /rike ! silicon1 !y set up a weak pulsat+ direct curr5t4 ,?is action is due to a peculi> rectify+ prop]ty ( ! m9]al4 ,! direct curr5t fl[s ?r\gh ! telephone receiv] & produces an audible s\nd4 ,if ! a]ial & gr\nd 7 connect$ directly to ! t]m9als ( ! telephone receiv]1 )\t ! silicon1 ! oscillations w\ld n pass because ( ! imp$+ or *ok+ action ( ! electro-magnets 9 ! telephone receiv]s4 99,tun+499--,x is sometimes desirable t messages %\ld be made selective or secretive4 ,x is obvi\s t if !re 7 sev]al l>ge /ations 9 ! same neighborhood !y c\ld n all op]ate at ! same "t unless "s means ( prev5t+ ! /ations f receiv+ m ?an "o message at a "t 7 possible4 ,?is is ! object 9 view ( ! s-call$ tun+ ( wireless telegraphy4 ,x also accompli%es a second purpose :i* is p]haps consid]$ m important ?an ! fir/4 ,! l5g? ( ! a]ial may be too great or too %ort = ! am\nt ( en]gy & ! l5g? ( ! waves :i* x emits or receives4 ,:5 ?is is ! case1 ! oscillations are quickly damp$ out & d n g5]ate v p[]ful waves or produce /rong signals at ! receiv+ /ation & ?us by prop]ly adju/+ ! circuit all undesirable messages may be cut out z well z ! signal+ range greatly increas$4 ,e electrical circuit has a def9ite p]iod or electrical l5g?1 det]m9$ by its inductance & capacity4 ,a circuit emits waves ( only "o l5g? = giv5 values ( inductance & capacity1 & mu/ also be ( a c]ta9 l5g? be=e x w respond to waves s5t out by ano!r transmitt]4 ,! c>eful adju/m5t ( a circuit to emit or receive a giv5 wave con/itutes tun+4 ,illu/ration3 ,fig4 #f4 ,resonance ,tube4 ,?is may be made m cle> by ! comp>ison ( an electrical circuit ) a column ( air4 ,fig4 #f repres5ts a cross section ( a glass tube1 ,t1 ly+ 9 a horizontal position & conta9+ a cork1 ,c1 :i* c be slid to v>i\s positions4 ,by adju/+ ! cork we are able to obta9 v>i\s dep?s ( air 9 ! tube f its op5 end1 ,m1 to ! cork1 ,c4 ,:5 a vibrat+ tun+ =k1 ,f1 is held opposite ! op5 m\? & ! cork slid back & =? x is f\nd t ! s\nd ( ! tun+ =k is greatly increas$ 9 volume at a c]ta9 position ( ! cork4 ,if ! cork is !n remov$ f ?is position ! s\nd decreases 9 int5sity4 ,:5 ! cork is 9 su* a position t ! s\nd ( ! =k is re5=c$1 we h secur$ resonance4 ,:5 9 ?is condition & ! prong ( ! vibrat+ =k is mov+ t[>d ! op5 m\? ( ! tube a cond5s$ pulse ( air travels d[n ! tube & back aga91 hav+ be5 reflect$ at ! cork & rea*+ ,m j z ! prong ( ! =k beg9s its excursion away f ! op5 m\? ( ! tube4 ,:5 ! prong ( ! =k is mov+ away f ,m a r>efi$ pulse ( air moves f ,m to ,c & back aga9 by ! "t ! prong is ready to beg9 its next vibration4 ,:5 ! tube is n 9 resonance1 ! successive cond5sations & r>efactions pass+ up & d[n ! air column int]f]e ) "o ano!r & decrease in/ead ( increase ! s\nd ( ! tun+ =k4 ,if we sub/itute ! s\nd waves emitt$ by ! tun+ =k = high frequ5cy oscillations & ! air column = ! electrical circuit we may readily see t by adju/+ its l5g?1 resonance c be produc$4 ,if ! l5g? ( ! air column is measur$ x w be f\nd t ! re5=c+ ( ! s\nd ( ! =k rea*es a maximum :5 ! dep? ( ! air column is "o-f\r? ( ! s\nd wave l5g? giv5 by ! =k4 ,likewise resonance is produc$ 9 wireless telegraphy :5 ! l5g? ( ! circuit is approximately "o-f\r? ! l5g? ( ! waves4 ,vice v]sa1 ! wave emitt$ f an ord9>y clos$ circuit transmitt] is approximately f\r times ! l5g? ( ! a]ial wire4 ,= example1 an a]ial #be met]s long w emit waves hav+ a l5g? 9 ! neighborhood ( #ajj met]s4 ,z /at$ above1 tun+ is accompli%$ & resonance or syntony e/abli%$ by v>y+ ! inductance & capacity ( ! circuit4 ,! capacity ( a circuit may be def9$ z its relative ability to reta9 an electrical *>ge1 :ile inductance is ! prop]ty ( an electric circuit by virtue ( :i* l9es ( =ce are develop$ ar\nd x4 ,capacity & inductance are opposite or reactive 9 _! effects ^u a circuit4 ,if ! value ( "o is decreas$ ! influ5ce ( ! o!r 9 increas$4 ,fig4 #g & ! foll[+ explanation w s]ve to illu/rate ?is4 ,illu/ration3 ,fig4 #g4 ,lag & ,lead4 ,alt]nat+ curr5ts d n always keep /ep ) ! voltage impulses ( a circuit4 ,if !re is inductance 9 ! circuit1 ! curr5t w lag beh9d ! voltage1 & if !re is capacity1 ! impulses ( ! curr5t w lead4 ,fig4 #g ,a illu/rates ! lag produc$ by inductance & ,b ! lead produc$ by capacity4 ,9 ,a ! impulses ( ! curr5t1 repres5t$ by ! full l9e1 occur a little lat] ?an ^? ( ! volts z repres5t$ by ! dott$ l9e4 ,9 ,b ! effect is j ! opposite & ! curr5t leads4 ,^! reactive effects ( inductance & capacity are v pron\nc$ ) ! high frequ5cy curr5ts ( wireless telegraphy1 &1 z /at$ be=e1 are ! factors :i* det]m9e ! p]iod ( ! circuit4 ,illu/ration3 ,fig4 #h4 ,tun$ ,hydraulic ,transmitt] & ,receptor4 ,tun+ is repres5t$ graphically 9 ,fig4 #h4 ,! two floats ,a & ,b are n only re/+ on ! surface ( a pool ( wat] z 9 ,fig4 #c b are also susp5d$ f ! spr+s ,s & ,s'4 ,! spr+s w h1 l a p5dulum1 a def9ite "t ( ris+ & fall+1 or p]iod ( oscillation1 dep5d+ ^u _! l5g?4 ,if we /rike ! float ,a ! spr+ w cause ! float to rise & fall at a def9ite rate & s5d out a little wave or ripple ) e oscillation4 ,if ! spr+s ,s & ,s' are ( ! same l5g?1 ! float ,b w be caus$ to oscillate ) e wave s5t out by ,a1 =1 ! p]iods ( ! spr+s be+ equal1 ,b w be p]mitt$ to rise ) a wave & fall aga9 j 9 "t to be rais$ by ! next oncom+ ripple4 ,on ! o!r h&1 if ! spr+s are ( diff]5t l5g?s1 ,b may only rise slightly & 9 fall+ meet an oncom+ wave :i* w cause x to rise be=e x has rea*$ its l[e/ po9t & s damp5 or weak5 its oscillations t !y ei!r d n become v /rong or are entirely oblit]at$4 ,?us sev]al floats hav+ diff]5t p]iods ( oscillation might be s5d+ out ripples 9 ! same pool1 & ! float ,b c\ld be made to respond to any ( !m by adju/+ ! l5g? ( ! spr+4 ,we may also see 9 ?is illu/ration ! "p t tun+ plays 9 caus+ ! app>atus to emit or receive m p[]ful impulses4 ,:5 ! rope 9 ! untun$ app>atus illu/rat$ 9 ,fig4 #c is j]k$1 ! block ,a oscillates only once or twice be=e a new j]k is requir$ to keep x 9 motion4 ,9 ,fig4 #h x is q ! contr>y1 = :5 an impulse has be5 giv5 to ! float ,a x w oscillate mu* long] ?an ! untun$ float be=e x requires to be set 9 motion aga94 ,likewise ! float ,b 9 ,fig4 #h w oscillate long] & m p[]fully ?an ! float ,b 9 ,fig4 #c1 :5 once x has be5 set 9 motion4 ,illu/ration3 ,fig4 #i4 ,tun$ ,wireless ,telegraph ,transmitt] & ,receptor ,fig4 #i %[s a diagram ( a simple wireless telegraph sy/em employ+ an inductance & capacity = tun+ ! circuits4 ,:5 ! induction coil is 9 op]ation x *>ges a cond5s]4 ,! cond5s] dis*>ges ?r\gh ! s5d+ helix & across ! sp>k gap4 ,! s5d+ helix is m]ely a spiral coil ( wire ( l>ge diamet]1 & con/itutes ! great] "p ( ! inductance 9 ! circuit4 ,two movable contacts1 ,a & ,b1 make connections ) ! helix4 ,! sp>k gap1 cond5s] & l[] portion ( ! helix up to ! movable contact ,a are kn[n z ! clos$ circuit4 ,by %ift+ ,a1 m or less inductance may be includ$ 9 ! clos$ circuit until resonance is secur$4 ,! a]ial1 ! inductance f ! contact ,b d[n1 ! cond5s] & ! gr\nd compose ! op5 circuit4 ,by v>y+ ! contact ,b m or less inductance may be includ$ 9 ! op5 circuit & its p]iod alt]$ until ! oscillatory curr5ts ( bo? circuits fl[ 9 ! same p]iod ( "t4 ,! clos$ & op5 portions ( ! transmitt+ helix =m an auto trans=m]1 & ! voltages ( ! op5 circuit are rais$ above ^? ( ! clos$ circuit4 ,! tun$ receptor %[n 9 ,fig4 #i is ! simple/ =m possible & is kn[n z ! s+le slide sy/em4 ,! tun+ coil or helix is mu* long] 9 proportion to its diamet] ?an ! s5d+ helix1 & is made ( f9] wire1 s9ce x does n c>ry su* heavy curr5ts4 ,:5 ! contact is slid up or d[n on ! tun+ coil1 ! inductance ( ! circuit is v>i$4 ,s9ce ! oscillat+ curr5ts 9 ! receiv+ a]ial h ! same frequ5cy z ^? 9 ! radiat+ a]ial1 ! receptor mu/ h ! same relative values ( inductance & capacity4 ,?is condition is obta9$ by v>y+ ! slid] until ! signals 9 ! telephone receiv]s are ! l\de/4 ,9 practice m ?an "o slid+ contact is us$1 & ^! toge!r ) adju/able cond5s]s make ! circuit m complicat$4 ,^! devices are necess>y because oscillations may be =c$ on a receptor by a ne>-by transmitt] unless o!r precautions ?an ! s+le slid] are tak54 ,su* circuits are illu/rat$ 9 ,plates ,,iv & ,v4 ,) !m x is possible to obta9 a consid]able degree ( selectivity & tune out an undesirable message4 ,,*apt] ,,ii4 ,,! ,,app>atus4 ,x is g5]ally ! receiv+ app>atus :i* fir/ attracts ! att5tion ( ! amateur op]ator1 & s x w be consid]$ fir/ "h4 ,an effici5t receiv+ set consi/s ( "s =m ( ,detector1 ,tun+ ,coil1 ,telephone ,receiv]s1 & ,cond5s]4 ,o!r accessories su* z adju/able cond5s]s1 pot5tiomet]1 batt]y & te/+ buzz] improve ! outfit & make x m complete4 ,! *oice ( ! type ( in/rum5ts mu/ be left entirely to ! p]son :o is con/ruct+ !m4 ,8 res\rces w det]m9e :e!r he is to use #a1jjj ohm telephone receiv]s built especially = wireless "w or ord9>y ones hav+ a resi/ance ( only #ge ohms4 ,x is !re=e be/ to read c>efully ! *apt]s devot$ to ! diff]5t pieces ( receiv+ app>atus & select ! type ( detector1 tun+ coil1 etc41 :i* x is desirable to use be=e comm5c+ ! con/ruction ( any4 ,= beg9n]s1 ,i w\ld recomm5d an outfit consi/+ ( a silicon detector1 a d\ble slide tun+ coil1 a cond5s] ( fix$ capacity & #ge-ohm telephone receiv]s4 ,su* an outfit ) a #ej-;foot a]ial w receive messages ab\t #aej miles4 ,if #a1jjj ohm telephone receiv]s are us$1 messages may be read up to #djj miles4 ,mu* dep5ds ^u ! location ( ! /ation & ! ability ( ! op]ator4 ,a m elaborate & effici5t set consi/s ( an electrolytic or ,p]ikon detector1 a trans=m+ tun]1 two adju/able cond5s]s1 a pot5tiomet] & a pair ( #a1jjj ohm telephone receiv]s4 ,?is outfit & a #ge-;foot a]ial c\ld be made to receive #ejj to #a1jjj miles by a c>eful op]ator4 ,sev]al cuts ( wireless app>atus built = private in/allation are %[n bo? 9 ?is *apt] & fur!r ?r\gh ! book1 to give an idea ( h[ ! bett] in/rum5ts ( ?is type are con/ruct$ & f9i%$4 ,illu/ration3 ,fig4 #aj4 ,long-di/ance ,receiv+ ,set4 ,fig4 #aj illu/rates a selective receiv+ set built by ! ,long ,di/ance ,wireless ,company4 ,! set is m\nt$ on a mahogany base & ! in/rum5ts are f9i%$ 9 poli%$ h>d rubb] & lacqu]$ brass4 ,!y comprise a detector /& s arrang$ t any ( ! s5sitive m9]als us$ 9 wireless "w may be us$4 ,! tun+ coil is ( ! d\ble slide type4 ,! cond5s] is seal$ up 9 a squ>e lacqu]$ brass tube fitt$ ) h>d rubb] ends & b9d+ po/s4 ,! arrangem5t & con/ruction ( ! outfit may be readily und]/ood f ! cut4 ,illu/ration3 ,fig4 #aa4 ,murdock ,receiv+ ,set4 ,fig4 #aa illu/rates a receiv+ set manufactur$ by ! ,wm4 ,j4 ,murdock ,company4 ,! tun+ coil is fitt$ ) h>d rubb] composition ends & is w\nd on a special core :i* is n affect$ by temp]ature *anges4 ,! detector is ( ! cry/al type & is ( r unique con/ruction1 s9ce ! small fix$ cond5s] is m\nt$ 9 ! base ( ! detector itself4 ,! ,clapp-,ea/ham set 9 ,fig4 #ab employs a receiv+ trans=m] :i* makes great selectivity possible4 ,! detector is m\nt$ at ! left-h& side ( ! outfit4 ,a v s5sitive m9]al call$ ,f]ron is us$ 9 ! detector4 ,! fix$ cond5s] is enclos$ 9 a brass tube fitt$ ) h>d rubb] ends & is locat$ on ! front ( ! base1 directly 9 ! c5t]4 ,a v>iable cond5s] ( ! rot>y type is plac$ at ! "r-h& corn]4 ,illu/ration3 ,fig4 #ab4 ,clapp-,ea/ham ,receiv+ ,set4 ,! ,prague ,electric ,company manufacture ! app>atus %[n 9 ,fig4 #ac4 ,! cab9et is mahogany & is fitt$ ) a h>d rubb] cov]4 ,a fix$ cond5s] & a d\ble slide tun+ coil are m\nt$ )9 ! cab9et4 ,! slid]s ( ! tun+ coil project ?r\gh two long slots 9 ! cab9et4 ,a univ]sal detector m\nt$ on top ( ! cab9et is s design$ t any mat]ial may be exp]im5t$ ) or te/$4 ,illu/ration3 ,fig4 #ac4 ,prague ,receiv+ ,set4 ,fig4 #ad %[s a receiv+ set built up f app>atus describ$ 9 ?is book4 ,! cab9et is #ab x #af in*es & #d in*es deep4 ,! wood %\ld be #a_/b in* ?ick1 & 9 ord] to pres5t a good appe>ance is pref]ably ( mahogany4 ,z mahogany is sometimes v h>d to procure & exp5sive1 "s may f9d r$ bir* an excell5t sub/itute4 ,:5 /a9$ ) a mahogany /a9 x pres5ts a f9e appe>ance4 ,illu/ration3 ,fig4 #ad4 ,receiv+ ,set4 ,v>ni%+ & poli%+ are wa/$ "t :5 appli$ to ! av]age amateur's in/rum5ts 9 view ( ! r\gh h&l+ & scrat*+ :i* !y receive4 ,! be/ plan is to /a9 ! wood ) an oil /a9 & give x a wax f9i%4 ,an oil /a9 conta9s no v>ni% b is m]ely color+ matt] & oil4 ,a good coat %\ld be appli$ ) a wide bru% & ! surplus /a9 imm$iately wip$ (f by rubb+ ! :ole surface ) a piece ( *eeseclo?4 ,z soon z ! /a9 is ?or\ghly dry ! wood is wax$4 ,cut up "s beeswax into f9e %r$s & place x 9 a j>4 ,p\r "s turp5t9e ov] ! beeswax & let ! mixture /& = five or six h\rs1 giv+ x an occasional /ir4 ,all[ x to /& fur!r if necess>y until ! wax melts & !n add en\gh turp5t9e to give ! mixture a consi/5cy simil> to t ( ?ick cream4 ,apply ! prep>ation to ! wood ) a rag1 & !n rub ) a piece ( clean *eeseclo? until ! f9i% is h>d & dry4 ,wax+ produces a gloss :i* is n s bright z a ,fr5* poli% b yet is m durable & n s easily scrat*$ or m>r$4 ,a d\ble slide tun+ coil made z describ$ 9 ,*apt] ,,xiv is m\nt$ on top ( ! cab9et 9 ! re>4 ,a univ]sal detector is m\nt$ 9 ! c5t]1 directly 9 front ( ! tun+ coil4 ,a tubul> cond5s] ( fix$ capacity is plac$ on ! left-h& side ( ! detector1 & a pot5tiomet] on ! opposite side4 ,a d\ble po9t swit* plac$ directly 9 front ( ! detector enables ! pot5tiomet] to be br\ght into play :5 a batt]y is us$4 ,f\r b9d+ po/s are m\nt$ on ! front ( ! cab9et4 ,! gr\nd & a]ial are connect$ to ! left-h& pair & ! telephone receiv]s to ^? on ! "r h&4 ,! wir+ diagram is %[n also 9 ,fig4 #ad4 ,by plac+ ! swit* ,a on contact #a1 ! pot5tiomet] is br\ght into use4 ,:5 on contact #b1 ! pot5tiomet] is cut out4 ,! swit* ,b mu/ be op5$ :5 ! detector is n 9 use s z n to run d[n ! batt]y4 ,illu/ration3 ,fig4 #ae4 ,receiv+ ,set4 ,fig4 #ae %[s a receiv+ set some:at simil> to t %[n 9 ,fig4 #ad b m elaborate & effici5t4 ,! cab9et 9 ?is case measures #ad x #bb in*es & is #f in*es deep4 ,a loosely c\pl$ or trans=m+ tun+ coil is us$ 9 place ( ! closely c\pl$ d\ble slide type4 ,two v>iable cond5s]s are m\nt$ on ei!r side ( ! tun+ coil4 ,! detector & pot5tiomet] occupy ! space directly 9 front ( ! tun+ coil1 :ile a fix$ cond5s] is plac$ at _! "r4 ,! two swit*es = break+ ! batt]y circuit & disconnect+ ! pot5tiomet] are 9 front ( ! detector4 ,! a]ial1 gr\nd & telephone receiv] leads are connect$ to b9d+ po/s m\nt$ on ! front ( ! cab9et4 ,! batt]ies1 9 bo? cases1 are plac$ inside ! cab9et4 ,! details & con/ruction ( all ! sep>ate in/rum5ts w be f\nd 9 ! respective *apt]s z d5ot$ by ! titles4 99,transmitt+ ,range499--,a simple transmitt+ outfit capable ( s5d+ ab\t two miles consi/s ( ! necess>y batt]ies1 a "o-in* sp>k induction coil1 a small z9c sp>k gap & a key4 ,! connections ( su* a transmitt+ outfit are %[n 9 ,fig4 #d4 ,if ! same coil is us$ ) a transmitt+ helix & a cond5s]1 ! range may be increas$ f #c to #e miles4 ,a #a #a_/b-;in* sp>k induction coil us+ a cond5s] & a transmitt+ helix w s5d ab\t #aj miles1 & a #c-;in* coil "u ! same conditions ab\t #bj miles4 ,a #d & a #f in* coil w transmit ab\t #cj & #dj miles respectively4 ,illu/ration3 ,fig4 #af4 ,murdock ,transmitt+ & ,receiv+ ,set4 ,! "o qu>t] kil[att trans=m] ) a helix & f\r two-qu>t leyd5 j>s or an equival5t cond5s] w transmit at lea/ #ej miles ) a suitable a]ial4 ,us$ z a "o half kil[att trans=m] ) a helix & eight two-qu>t leyd5 j>s1 x w s5d ab\t #ajj miles4 ,( c\rse1 z 9 ! case ( ! receiv+ outfits1 ^! di/ances are approximate & dep5d ^u ! location ( ! /ation1 ! nature ( ! gr\nd ov] :i* ! messages are transmitt$1 ! k9d ( receptor us$ at ! receiv+ /ation & ! effici5cy ( ! op]ator himself4 ,fig4 #af illu/rates a complete ,murdock transmitt+ & receiv+ set4 ,! transmitt+ outfit consi/s ( a #ae-watt induction coil giv+ ab\t a "o-in* sp>k1 a s5d+ helix1 oscillation cond5s]1 a key & a d\ble pole d\ble ?r[ swit* = *ang+ ! ant5na & gr\nd f ! transmitt+ to ! receiv+ in/rum5ts or vice v]sa4 ,! sp>k gap is m\nt$ on top ( ! coil4 ,! receiv+ outfit is ! same z t illu/rat$ 9 ,fig4 #aa4 99,a complete wireless /ation99--outside ( ! a]ial consi/s prim>ily ( a s\rce ( electrical en]gy1 a trans=m] or induction coil = *>g+ ! oscillation cond5s]1 an oscillation cond5s]1 a transmitt+ helix1 a key = break+ ! prim>y curr5t1 a sp>k gap1 an a]ial swit*1 a hot wire ammet] = tun+ ! transmitt+ circuits1 a detector1 a receiv+ tun]1 auxili>y tun+ app>atus su* z fix$ & v>iable cond5s]s1 a pot5tiomet] & batt]y1 & a pair ( telephone receiv]s ) a headb&4 ,o!r app>atus su* z swit*es1 insulators1 an*or gaps1 te/+ buzz]s1 reactance coils1 gr\nd+ swit*es1 etc41 h be5 describ$ 9 v>i\s places ?r\gh\t ! book & _! use sugge/$ :5ev] x is ( any advantage4 ,! *oice ( transmitt+ in/rum5ts1 z ) ! receiv+ app>atus1 is left entirely ) ! exp]im5t] s t he may suit 8 ideas & means4 ,:]ev] possible ! range & p[] ( ! in/rum5ts h be5 giv5 & sugge/ions made z to ! o!r app>atus :i* %\ld be us$ 9 connection ) !m s t ! complet$ outfit w be> "s s5se ( proportion4 ,illu/ration3 ,fig4 #ag4 ,unit$ ,wireless ,portable ,outfit4 ,fig4 #ag illu/rates ! portable wireless telegraph set manufactur$ by ! ,unit$ ,wireless ,telegraph ,company = army s]vice & explor+ exp$itions or isolat$ camps4 ,! a]ial & ! ma/ c be unload$1 erect$1 & all p>ts be ready = op]ation 9 fifte5 m9utes4 ,! ma/ is made ( int]*angeable wood5 sections4 ,! curr5t = ! transmitt] is furni%$ by a portable /orage batt]y4 ,! :ole outfit is capable ( furni%+ effici5t s]vice = di/ances ( #be to #cj miles4 ,,*apt] ,,iii4 ,,a]ials ,,& ,,e>? ,,connections4 ,! a]ial or ant5na ord9>ily consi/s ( a numb] ( wires elevat$ 9 ! air to emit or int]cept ! ,h]tzian waves4 ,9 fitt+ up a wireless /ation ! location & erection ( an a]ial are ( prime importance1 & ! successful reception & transmission ( wireless messages w dep5d l>gely ^u its condition4 ,a few ye>s ago ! wireless ant5na consi/$ ( a metal plate high 9 ! air & hav+ a wire susp5d$ f x1 b to-day usually exi/s 9 "o ( ! =ms illu/rat$ 9 ,plate ,,ii4 ,! high] an a]ial is plac$ above ! surface ( ! e>?1 ! wid] w be its electro/atic field1 & consequ5tly m p[]ful electrical waves w be develop$4 ,b aft] a height ( #ahj-bjj feet is atta9$1 ! eng9e]+ difficulties & ! exp5ses increase s rapidly t few /ations exce$ x4 ,o!r ?+s be+ equal1 ! increas$ range 9 transmitt+ v>ies z ! squ>e ( ! height ( ! radiat+ wires4 ,= example1 a #be-;foot a]ial capable ( transmitt+ "o mile !oretically w s5d waves #af miles if made #ajj feet high4 ,! actual ratio is (t5 great]1 b mu* is dep5d5t ^u ! _m meteorological conditions4 ,aft] ! limit 9 a v]tical direction has be5 rea*$1 ! only rema9+ possibilities are to increase ! surface & spread out horizontally4 ,! flat top a]ials are us$ on %ipbo>d or :]ev] x is an advantage to susp5d ! wires betwe5 two ma/s4 ,!y are especially recomm5d$ = amateur use1 s9ce !y ne$ n be s high z ! o!r a]ials1 to be effici5t4 ,! flat top a]ials are directive1 t is1 !y receive or radiate waves bett] 9 c]ta9 directions4 ,! b5t or inv]t$ ,l type is "o ( ^! & exhibits a pref]5ce = waves com+ f a direction opposite to t 9 :i* its free end po9ts4 ,?is directive action ( an inv]t$ ,l ant5na may be some:at less5$ if ! leads are tak5 (f at ! c5t] & x is made a ,t a]ial4 ,?is is ! mo/ common =m ( flat top a]ial 9 use on %ips4 ,! inv]t$ ,u type is n us$ ext5sively because ! two opposite leads or rat-tails make a c5trally locat$ op]at+ room necess>y4 ,! loop a]ial is us$ by ! ,unit$ ,wireless ,company1 9 bo? _! %ip & l& /ations4 ,?is type ( a]ial is well adapt$ to long waves & close tun+4 ,! ,lodge-,muirhead capacity a]ial does n make use ( a gr\nd & is r>ely se5 9 ?is c\ntry4 ,lately ! ,unit$ ,/ates ,signal ,corps h appli$ x to _! balloons :]e an e>? connection w\ld be impossible4 ,! upp] "p ( ! balloon is cov]$ ) a network ( wires :i* s]ves z ! upp] a]ial1 & a second sy/em ( wires is susp5d$ bel[ ! balloon to take ! place ( ! gr\nd4 ,by ?is means !y h _h little difficulty 9 e/abli%+ successful communication betwe5 ! balloons & ! e>?4 ,! pyramid a]ial is ! type us$ by ,m>coni 9 long-di/ance ultra-p[]ful /ations1 b is deb>r$ f ext5sive in/allation on acc\nt ( ! l>ge co/ ( erection4 ,! cage & grid a]ials are ( ! v]tical type & are excell5t :]e a high support to elevate !m c be secur$4 ,!y are at pres5t us$ pr9cipally by ! ,massie & ,/one ,companies4 ,illu/ration3 99,plate ,,ii4 ,a]ial ,sy/ems499 ,! desirable feature ( an a]ial is a quantity kn[n z its electro/atic capacity & is measur$ by ! *>ge requir$ to raise its pot5tial "o unit4 ,an increase 9 capacity enables m en]gy to be accumulat$ 9 ! ant5na1 & consequ5tly great] radiation results4 ,! capacity ( an a]ial may be increas$ by add+ wires1 b mu/ n be c>ri$ too f> or ! transmitt+ app>atus w n be able to raise its pot5tial suffici5tly4 ,ow+ to an effect caus$ by mutual induction betwe5 ! wires1 ! l9es ( /ra9 are n di/ribut$ symmetrically1 & ! capacity w n v>y directly b r approximately z ! squ>e root ( ! numb] ( wires4 ,9 ord] to decrease ?is action & use ! surface mo/ effici5tly1 ! wires %\ld n be plac$ ne>] ?an "o-fiftie? ( _! l5g? & pref]ably f>!r ap>t4 ,! mat]ials us$ = ! insulation & susp5sion ( an a]ial mu/ be reliable1 s t 9 ev5t ( bad wea!r ! /ation w n lose en]gy or be put out ( work+ ord] because ! a]ial blew d[n4 ,porcela9 cleats or a /r+ ( porcela9 insulat+ knobs make inexp5sive insulators4 ,! /&>d insulator = wireless telegraph "w is ! ,electrose insulator4 ,^! are made ( a mold$ composition1 & h iron r+s set firmly 9 ! ends s t !y c )/& a v heavy /ra94 ,h>d rubb] is undesirable = an a]ial insulator because x becomes c>boniz$ & cov]$ ) a conduct+ lay]4 ,illu/ration3 ,fig4 #ah4 ,electrose ,insulators4 ,high frequ5cy curr5ts p]meate copp] wire only ab\t "o ?ree-hundr$? ( an in*1 & s1 9 ord] to increase ! surface & decrease ! resi/ance1 x is be/ to make ! a]ial ( /r&$ wire4 ,a phosphor bronze wire = ?is purpose :i* is v flexible b /ill does n sag or /ret*1 is compos$ ( #g /r&s ( ,no4 #bj ,b4 ,s4 gauge4 ,su* a wire #aej feet long susp5d$ v]tically & insulat$ f ! e>? w h a capacity ( f #j4jjjc to #j4jjjd ( a micr(>ad4 ,! a]ial mu/ receive v p>ticul> att5tion if ! /ation is "o kil[att or ov] 9 p[]4 ,9 t case /r&$ wire is necess>y4 ,! insulation ( ! a]ial mu/ be z ?or\gh z possible1 & proximity to l>ge conductors su* z smoke/acks1 telephone l9es1 etc41 avoid$4 ,rope /ays & guys are advisable 9 ord] to prev5t dissipation ( en]gy4 ,if wire /ays mu/ be us$ !y %\ld be divid$ up at frequ5t int]vals by insulators4 ,fig4 #ai illu/rates a guy insulator us$ by ! ,unit$ ,wireless ,telegraph ,company4 ,x is made ( two /rips ( well p>aff9$ wood sep>at$ by two porcela9 knob insulators4 ,illu/ration3 ,fig4 #ai4 ,guy ,insulator4 ,copp] wire is ! mo/ desirable = an a]ial4 ,iron wire mu/ nev] be us$ unless x is v heavily galvaniz$1 & ev5 !n x is n to be recomm5d$4 ,alum9um wire is undesirable except = kite su/a9$ a]ials4 ,:5 us$ on an a]ial & expos$ to smoke & o!r fumes x becomes quickly coat$ ) a lay] ( oxide4 ,all connections made 9 alum9um wire mu/ be sold]$4 ,?is necessity may be bett] und]/ood :5 x is expla9$ t electro-magnets on dynamos1 etc41 are sometimes w\nd ) b>e alum9um wire & t ! natural coat+ ( oxide on ! wire is suffici5t insulation to sep>ate ! turns4 ,illu/ration3 ,fig4 #bj4 ,insulat+ ,tube4 ,:]e ! a]ial ent]s ! build+ 9 :i* ! in/rum5ts are locat$ x mu/ be v c>efully insulat$4 ,! simple/ me?od is to bore a hole ?r\gh ! wall & pu% a porcela9 tube ?r\gh x4 ,! rat-tail or lead+-9 wire is !n pass$ ?r\gh & ! int]/ices betwe5 x & ! tube p\r$ full ( melt$ p>aff94 ,! be/ me?od is to bore a hole 9 ! w9d[ pane & pass ! wire ?r\gh a h>d rubb] insulat+ tube4 ,fig4 #bj %[s su* a tube4 ,x is ?ree-qu>t]s ( an in* 9 outside diamet] & has an int]nal bore ( ?ree-eigh?s ( an in*4 ,! tube is ?read$ ?r\gh\t its entire l5g?4 ,two h>d rubb] flanges in* ?ick & #b in*es 9 diamet] are ?read$ to screw on ! tube4 ,! tube is ins]t$ 9 ! hole 9 ! w9d[ pane & ! flanges screw$ on ei!r side4 ,if a s(t rubb] wa%] is plac$ betwe5 ! h>d rubb] flanges & ! pane !re w be less likelihood ( crack+ ! glass4 ,! lead+-9 wire is !n pass$ ?r\gh ! tube4 ,! hole 9 ! w9d[ pane may be bor$ by us+ a copp] tube hav+ an ext]nal diamet] equal to t ( ! requir$ hole4 ,! tube is set 9 a brace & us$ l an ord9>y bit1 b mu/ be kept well sme>$ ) em]y & oil or else x w n cut4 ,?is me?od ( lead+ 9 ! rat-tail is ! only "o to be recomm5d$ if ! transmitt] is "o-qu>t] kil[att or ov] 9 p[]4 ,illu/ration3 ,fig4 #ba4 ,high-t5sion ,cable & ,insulator4 ,! lead-9 %\ld be an*or$ j outside ( ! w9d[ s z to relieve ! glass pane & ! tube f all /ra94 ,pirelli cable or ! high-t5sion cable :i* is us$ = ! second>y wir+ ( an automobile is ! be/ conductor to use = ! a]ial 9 ! int]ior ( a build+4 ,! way to lead x ov] ! ceil+ is to support x on a porcela9 cleat simil> to t %[n 9 ,fig4 #ba4 ,_m are "u ! errone\s impression t f\r times ! l5g? ( ! a]ial is ! wave l5g? :i* ! /ation w emit4 ,?is is only at ! be/ a v r\gh approximation1 = _m undet]m9able factors su* z ! nature & location ( surr\nd+ objects1 trees1 etc41 s affect ! capacity & inductance ( ! a]ial t ! wave l5g? mu/ be det]m9$ empirically aft] ! a]ial is 9 op]ation4 ,! /&>d wave l5g? ( ! ,unit$ ,/ates ,navy = %ip in/allations is #dbe met]s4 ,an inv]t$ ,l a]ial1 calculat$ be=e erection to h a wave l5g? z ne> z possible to ?is1 has ! foll[+ dim5sions3 ,f\r horizontal /r&$ phosphor bronze wires 7#g /r&s ,no4 #bj ,b4 ,s47 ea* #afj feet long & spac$ #e feet ap>t1 f\r v]tical wires #he feet long & a #ce-;foot rat-tail4 ,x is always desirable t ! wave l5g? %\ld be z long z possible1 = ! waves w !n travel f>!r & are n absorb$ to su* an ext5t by trees1 etc4 ,! absorption due to trees is said to v>y z ! f\r? p[] ( ! frequ5cy4 ,x is sometimes v conv5i5t to calculate ! /ra9 on insulators or ma/s caus$ by a horizontal ant5na4 ,?is is easily f\nd by ! foll[+ equation3 ,p equals ,l x ,w_/#h,s :]e ,p is ! requir$ /ra9 9 lbs41 ,w ! weight 9 lbs4 p] foot ( a]ial1 ,l ! l5g? ( ! a]ial & ,s ! sag ( ! wire 9 feet4 ,:5 erect+ an a]ial1 x is be/ to fa/5 a pulley at ! top ( ! support+ ma/ & hoi/ ! a]ial up aft] ! pole is 9 position4 ,!n 9 case ! wires become twi/$ or brok5 !y may be l[]$ & repair$ )\t any difficulty4 99,erection ( an ,a]ial499--,! av]age amateur a]ial is g5]ally f #dj to #fj feet high & support$ at "o end by a %ort pole plac$ on ! h\se & at ! o!r end by a ma/ set 9 ! gr\nd or la%$ to a tree4 ,fig4 #bb illu/rates su* an arrangem5t :]eby a flat-top ,t a]ial is support$ at "o end by a %ort pole fa/5$ to ! h\se & at ! o!r end by a pole set 9 ! gr\nd4 ,illu/ration3 ,fig4 #bb4 ,flat-top ,t ,a]ial4 ,! flat-top loop a]ial is pref]r$ by "s amateurs & x is to be recomm5d$ = receiv+ b is an ineffici5t radiator4 ,:5 ?is type ( a]ial is us$ ! two lead+-9 wires %\ld be connect$ to a swit* s t :5 ! swit* is clos$ !y are connect$4 ,! a]ial may !n be us$ z a /raight-away a]ial = transmitt+1 & by op5+ ! swit*1 z a loop a]ial = receiv+4 ,?is precaution is advis$ :5 a loop a]ial is to be us$ ) a l[-p[]$ induction coil z a transmitt]1 = o!rwise !re w be a loss ( en]gy at ! an*or gap4 ,a l>ge a]ial is ( no advantage :5 us$ ) a small trans=m] or induction coil because x _c become prop]ly *>g$4 ,to erect a flat-top ,t a]ial1 fir/ select its location4 ,if possible take advantage ( two trees & la% a %ort pole 9 ! top ( ea*1 s t ! a]ial may be rais$ up cle> ( ! leaves4 ,ano!r good plan is to erect a pole at ea* end ( ! h\se4 ,9 any case1 ! di/ance sep>at+ ! poles mu/ n be great] ?an ?ree times ! height above gr\nd or ! directive action ( ! a]ial w be v pron\nc$4 ,an a]ial #ej to #fj feet high %\ld h a l5g? ( f #hj to #ajj feet4 ,/r&$ wire is no advantage = receiv+1 b mu/ be us$ if ! transmitt] is o!r ?an a small induction coil4 ,secure two spruce /icks ab\t #b in*es 9 diamet] & #aj feet long4 ,fa/5 an insulator #f in*es f ea* end ( ! sp>s & two m ea* #c ,j feet f ! ends4 ,?is arrangem5t w sep>ate ea* ( ! f\r wires :i* compose ! a]ial by ?ree feet4 ,! two sp>s are !n laid on ! gr\nd at a di/ance ap>t equal to ! desir$ l5g? ( ! a]ial4 ,f\r wires1 ei!r /r&$ or ,no4 #ab ,b4 ,s4 gauge copp]1 are cut to equal l5g?s & fa/5$ to ! correspond+ insulators4 ,! middle ( ea* wire is f\nd & a long copp] wire sold]$ to x4 ,^! f\r wires con/itute ! rat-tail or lead-94 ,!y %\ld be ( ! same l5g?1 & are n connect$ toge!r until !y are ab\t to ent] ! build+4 ,a %ort rope ti$ to ea* end ( ! sp>s & fa/5$ to ! rope :i* passes ov] ! pulley on ! top ( ! pole1 s]ves z a bridle to prev5t ! a]ial f twi/+4 ,! a]ial is !n hoi/$ up b all[$ to hang slightly slack4 ,!re is consid]able diff]5ce ( op9ion among exp]ts z to :e!r or n ! ends ( ! horizontal wires %\ld be connect$1 & x is impossible to say ) good reason :i* me?od is bett]4 ,h[ev]1 :5 erect+ a flat top a]ial1 ex]cise e c>e to make all ! wires ( exactly ! same l5g?4 ,an a]ial ( ! size & type j describ$ w s5d & receive ! foll[+ di/ances4 ,^! di/ances are only approximate & w v>y ) ! effici5cy ( ! op]ator & ! location ( ! /ation4 ,:5 any ( ! trans=m]s describ$ lat] are us$1 ! a]ial %\ld be #hj to #ajj feet high4 ,9 ?is case ! la/ nam$ receiv+ outfit w h a range ( f #ejj to #a1jjj miles4 99,gr\nd ,connections499--,! importance ( a good e>? or gr\nd connection c h>dly be ov]e/imat$4 ,:5ev] possible comm]cial /ations are locat$ on moi/ gr\nd or ne> a body ( wat] s t a good gr\nd may be secur$ by imb$d+ z9c or copp] plates 9 ! e>? or wat]4 ,a gr\nd on %ipbo>d is easily secur$ by fa/5+ a conductor to "o ( ! %ip's plates4 ,if ! gr\nd connection is poor1 ! natural p]iod ( ! oscillation circuit is made irregul> & %ort1 s t ! curr5ts are *ok$ 9 pass+ 9 & out ( ! e>?4 ,! result is an undesirable rise ( pot5tial at ! l[] end ( ! a]ial & (t5 h>mful sp>k+ at ! gr\nd connection4 ,! transmitt+ & receiv+ ranges ( a /ation are v consid]ably r$uc$ ?r\gh a poor e>?4 ,gr\nd connection c (t5 be obta9$ 9 ! c\ntry by imm]s+ metal plates 9 a well or a ci/]n4 ,:]e connection is made to a wat] supply pipe "s sort ( a gr\nd clamp %\ld be us$ to insure a good contact4 ,illu/ration3 ,fig4 #bc4 ,gr\nd ,clamp4 ,an effici5t e>? = portable outfits may be quickly =m$ by spread+ a l>ge area ( wire nett+ ov] ! gr\nd4 ,prop] precautions = protection aga9/ lightn+ by gr\nd+ ! a]ial outside ( ! build+ %\ld be tak54 ,! wise/ plan is to in/all a heavy s+le pole d\ble ?r[ swit* outside ( ! build+ :]e ! rat-tail ent]s4 ,! knife ( ! swit* %\ld be connect$ to ! a]ial1 "o contact to ! h\se lead & ! o!r to a heavy wire gr\nd$ on ! outside ( ! build+ z 9 ,fig4 #bd4 ,:5 ! app>atus is n 9 use ! a]ial %\ld be gr\nd$ by ?r[+ ! swit* on ! gr\nd$ contact4 ,illu/ration3 ,fig4 #bd4 ,swit* = ,lightn+ ,protection4 ,! rul+s ( ! ,national ,bo>d ( ,fire ,und]writ]s gov]n+ ?is class ( "w are app5d$ bel[4 #a4 ,a]ial conductors to be p]man5tly & effectively gr\nd$ at all times :5 ! /ation is n 9 op]ation by a conductor n small] ?an ,no4 #d ,b4 ,s4 gauge copp] wire1 run 9 a direct l9e z possible to wat] pipe on /reet side ( said wat] pipe )9 ! premises or to "s o!r equally satisfactory e>? connection4 #b4 ,a]ial conductors :5 gr\nd$ z above specifi$ mu/ be effectually cut (f f all app>atus )9 ! build+4 #c4 ,or ! a]ial to be p]man5tly connect$ at all times to e>? 9 ! mann] specifi$ above1 ?r\gh a %ort gap lightn+ arre/]2 said arre/] to h a gap ( n ov] 4#jae ( an in* betwe5 brass or copp] plates n less ?an #b #a_/b in*es 9 l5g?1 p>allel to ! gap1 & #a #a_/b in*es ! o!r way1 ) a ?ickness ( n less ?an "o-eigh? ( an in*1 m\nt$ on non-combu/ible1 non-absorptive insulat+ mat]ial ( su* dim5sions z to give ample /r5g?4 ,o!r approv$ arre/]s ( equally l[ resi/ance & equally sub/antial con/ruction may be us$4 #d4 ,9 cases :]e ! a]ial is gr\nd$ z specifi$ 9 p>agraph #a1 ! swit* employ$ to jo9 ! a]ial to ! gr\nd connection %all n be small] ?an a /&>d #ajj-;amp]e jack-knife swit*4 ,notice ( wir+ done = ^! in/allations %\ld be s5t to ! ,bo>d1 ! same z = all o!r "w4 ,,*apt] ,,iv4 ,,induction ,,coils4 ,"s means ( *>g+ ! cond5s] :i* produces ! oscillatory dis*>ge is necess>y4 ,an induction coil is ! mo/ practical = ! amateur4 ,! induction coil consi/s ( a prim>y coil ( wire w\nd ar\nd a c5tral iron core & surr\nd$ by a second>y coil consi/+ ( _m ?\s& turns ( c>efully insulat$ wire4 ,! prim>y coil is connect$ to a s\rce ( direct curr5t :i* also includes an int]rupt] to make & break ! curr5t 9 rapid succession4 ,e make ( ! circuit & consequ5t magnetization ( ! core induces a mom5t>y inv]se curr5t 9 ! second>y1 & e break & correspond+ demagnetization a mom5t>y direct curr5t4 ,normally1 ! induc$ curr5ts w\ld be equal1 b by means ( a cond5s] %unt$ across ! int]rupt] ! circuit :5 made requires consid]able "t = ! curr5t & magnetization ( ! core to rea* a maximum value1 :ile :5 brok5 ! demagnetization & curr5t drop are ne>ly in/antane\s4 ,! value ( ! induc$ electromotive =ce 9 a circuit v>ies z ! spe$ at :i* ! magnetic l9es ( =ce cut ! circuit1 & s ! induc$ e4m4f4 at break is ?us r5d]$ high en\gh to leap across a gap 9 ! %ape ( sp>ks4 ,! =mulas connect$ ) induction coils dep5d ^u conditions :i* are nev] met 9 actual practice & _c be reli$ ^u4 ,to con/ruct a coil ( a giv5 size1 x is necess>y to use dim5sions obta9$ empirically4 ,!re=e x is well = ! amateur to /ick closely to l9es & h9ts :i* are giv5 "h or :i* appe> 9 "s up to date book on induction coil build+4 ,illu/ration3 ,fig4 #be4 ,diagram ( an ,induction ,coil4 ,= a long "t ! induction coil 0 an exp5sive1 ineffici5t in/rum5t1 until wireless telegraphy dem&$ ( x m rigid & effici5t design & con/ruction4 ,x 0 ! aim ( manufactur]s to produce ! longe/ possible sp>k l5g? ) a m9imum am\nt ( second>y wire4 ,z a result ( ?is dem&1 wireless coils are n[ made ) a core ( l>ge diamet] & give heavi] & ?ick] sp>ks4 ,! second>y 9 ?is case is %ort & uses wire ( l>ge cross section 9 ord] to r$uce ! resi/ance & m9imize ! heat+4 ,no "o "p ( an induction coil may be develop$ to its maximum effici5cy )\t s]i\sly influ5c+ & l[]+ ! effici5cy ( ! o!r p>ts4 ,! foll[+ sugge/ions reg>d+ ! con/ruction are giv5 t !y may prove a useful guide to ! amateur coil build]4 ,! p>ts w be consid]$ 9 _! natural ord] ( con/ruction4 99,core499--,"s exp]im5t]s n q famili> ) ! pr9ciples ( magnetism reason t if an induction coil 7 provid$ ) a clos$ core z ! trans=m]1 ! effici5cy ( ! coil w\ld be mat]ially increas$4 ,b ?is is n s1 = ! magnetization & demagnetization ( ! iron _c take place rapidly en\gh 9 a clos$ core :5 an int]rupt$ direct curr5t is employ$ 9 place ( an alt]nat+ curr5t4 ,! core ( an induction coil is !re=e always /raight4 ,= ! same reason1 x is nev] solid b is made up ( a bundle ( s(t iron wires 9 ord] t rapid *anges 9 magnetism may take place4 ,! wires are always ( z high a p]meability z possible s z to create a /rong magnetic field4 ,sw$i% or ,russian iron ( a good quality is ! be/1 z its hy/]esis losses are small4 ,! small] ! diamet] ( ! wire ! less w be ! eddy curr5t losses & heat+1 b ! p]meability is also r5d]$ less & ! core w n be s effective1 z ! am\nt ( iron is !reby decreas$ & ! oxidiz$ surface increas$4 ,no4 #bb ,b4 ,s4 gauge wire is ! be/ size = ! av]age core4 ,wires ( a good quality may be pur*as$ already cut to v>i\s l5g?s4 ,to buy !m 9 ?is =m w save a great deal ( ! labor requir$ 9 build+ a core4 ,if ! wires are n q /raight !y may be /raight5$ by roll+ !m1 "o at a "t1 betwe5 two bo>ds4 ,x is be/ to reanneal ! wires 9 ! foll[+ mann]4 ,place !m 9 an iron pipe & plug ! ends ( ! pipe ) clay4 ,!n lay x 9 a coal fire until ! :ole mass atta9s a r$ heat4 ,! fire is !n all[$ to die out gradually ) ! pipe & wires rema9+ 9 ! a%es until cool4 ,:5 cool remove !m f ! pipe & rub ea* "o ) em]y pap] until bright4 ,aft] ?is clean+1 ! wires are dipp$ 9 hot wat] & dri$4 ,!y are !n dipp$ 9 a good quality ( v>ni% & all[$ to dry aga94 ,illu/ration3 ,fig4 #bf4 ,induction ,coil ,core4 ,! v>ni% s]ves to int]pose resi/ance to ! eddy curr5ts g5]at$ 9 ! core & r5d]s ! losses due to ?is cause mu* less4 ,a /rong pap] tube hav+ an int]nal diamet] equal to ! diamet] ( ! f9i%$ core is made by roll+ ! pap] on a =m & cem5t+ ) %ellac4 ,:5 p]fectly dry4 ! tube is remov$ & ! wires tightly pack$ 9 x4 ,! foll[+ table gives ! core dim5sions = practical coils ( diff]5t sizes4 99,prim>y ,w9d+499--,! ratio ( ! numb] ( prim>y turns ( an induction coil to ! numb] ( second>y turns be>s no relation to ! ratio ( ! prim>y & ! second>y curr5ts4 ,x has be5 f\nd 9 practice t two lay]s ( wire w\nd tightly on ! core con/itute ! be/ prim>y4 ,! prim>y %\ld always be ?or\ghly %ellack$ or cov]$ ) insulat+ v>ni%4 ,s9ce !re is almo/ no v5tilation 9 ! prim>y ! wire mu/ be l>ge en\gh to avoid all heat+4 ,a table conta9+ ! v>i\s sizes ( prim>y wires is giv5 bel[4 ,9 l>ge coils1 ! inductance ( ! prim>y causes a kick back & sp>ks are liable to pass betwe5 ! adjac5t turns4 ,= ?is reason1 x is always well to use d\ble cotton cov]$ wire & to fur!r ?or\ghly insulate x by soak+ ! prim>y & core 9 a pan ( melt$ p>aff9 & all[+ !m to h>d5 !re94 ,aft]w>ds ! pan is slightly w>m$ to loos5 ! cake ( p>aff9 & ! excess ( wax remov$ by scrap+ ) a blunt in/rum5t s z n to injure ! wires4 ,p>aff9 contracts ^u h>d5+1 & ! prop] me?od to impregnate a por\s sub/ance is to all[ x to soak & become set 9 x ^u cool+4 ,a good me?od ( r$uc+ ! kick back & also ! size ( ! cond5s] %unt$ across ! int]rupt] is to =m ! prim>y ( a numb] ( turns ( small] wire 9 p>allel1 ! effect be+ to give a conductivity equal to a s+le wire ( l>ge diamet] & at ! same "t to make a m compact w9d+ ( ! prim>y on ! core4 ,?is me?od ( w9d+ is v desirable 9 l>ge coils1 z x r$uces ! cross section ( ! prim>y & all[s ! second>y to be plac$ ne>] ! core1 :]e ! magnetic field is ! /ronge/4 ,! prim>y w9d+ ought to occupy ne>ly ! :ole l5g? ( ! core1 s9ce !re is no ga9 9 c>ry+ ! end ( ! core v f> beyond ! end ( ! prim>y1 = mo/ ( ! magnetic l9es ( =ce b5d at ! end ( ! prim>y & return )\t pass+ ?r\gh ! extreme ends ( ! core4 99,insulat+ ,tube499--,! successful op]ation ( an induction coil )\t break+ d[n :5 "u /ra9 dep5ds l>gely ^u ! insulat+ tube :i* sep>ates ! prim>y & second>y4 ,h>d rubb] tubes are p]haps ! be/4 ,a tube may be easily built up ( sev]al lay]s ( #a_/b-;in* %eet h>d rubb] by /eam+ x s z to s(t5 x & !n wrapp+ x ar\nd a =m4 ,! tube %\ld fit ! prim>y tightly & be ab\t "o in* %ort] ?an ! core4 ,aft] ! tube is 9 place x is p\r$ full ( beeswax & ros9 9 ord] to fill all int]/ices & prev5t sp>ks due to ! cond5s] effect ( ! w9d+s f jump+ f ! inside ( ! tube to ! prim>y4 99,second>y499--,a coil us$ z a wireless telegraph transmitt] mu/ h wire ( l>ge cross section 9 its second>y s z to obta9 a heavy disruptive dis*>ge4 ,numb]s #cd & #cb ,b4 ,s4 are g5]ally us$ = small coils & numb]s #cj & #bh ,b4 ,s4 = l>ge coils4 ,silk cov]$ wire is ! usual practice1 b enamel$ wire is com+ into use4 ,cotton cov]$ wire takes up too mu* space & has poor] insulat+ qualities4 ,enamel$ wire is insulat$ by a coat+ ( cellulose acetate1 :i* has a dielectric /r5g? ( ab\t twice t ( cotton & takes up mu* less room ?an silk4 ,!re is1 !n1 ) enamel$ wire a great sav+ 9 space1 & a great] numb] ( turns may be plac$ on ! second>y )\t increas+ its mean di/ance f ! core4 ,! foll[+ table %[s ! comp>ative diamet]s ( silk & enamel cov]$ wires suitable 9 size = use on ! second>ies ( induction coils4 ,9 w9d+ enamel$ wire x mu/ be tak5 into consid]ation t ! insulation ( enamel$ wire is rigid & has no give4 ,consequ5tly1 to all[ = expansion1 enamel$ wire mu/ be m loosely w\nd ?an fib] or silk cov]$ wire4 ,! occasional ins]tion ( a lay] ( pap] 9 w9d+ w give room = expansion & at ! same "t n add greatly to ! diamet]4 ,illu/ration3 ,fig4 #bg4 ,!oretical & practical =m ( second>y4 ,! l5g? ( ! second>y is g5]ally n mu* m ?an "o-half ! l5g? ( ! core4 ,coils giv+ sp>ks up to #b in*es 9 l5g? may be w\nd 9 two sections or 9 lay] w9d+s1 b ! lay] w9d+ is n recomm5d$ = coils giv+ sp>ks ov] "o in*4 ,x is be/ 9 a coil ( ?is k9d to ins]t an occasional lay] ( pap]4 ,! pap] %\ld be well %ellack$ or p>aff9$ & be ( a good grade ( l954 ,x %\ld project ab\t "o-qu>t] ( an in* f ! ends ( ! second>y z %[n by ! sectional draw+ 9 ,fig4 #bh4 ,?is ins]tion ( pap] increases ! insulation & r5d]s ! liability ( sp>ks jump+ f lay] to lay] mu* less1 z is ! case :5 ! lay]s are v long4 ,illu/ration3 ,fig4 #bh4 ,lay] ,w9d+ = ,small ,coils4 ,! second>ies ( l>ge coils are made up ( pies or pancakes f "o-eigh? to ?ree-eigh?s ( an in* 9 ?ickness4 ,! pies are sep>at$ f ea* o!r by a triple ?ickness ( blott+ pap] :i* has be5 ?or\ghly dri$ & !n soak$ 9 melt$ p>aff94 ,9 cutt+ ! blott+ pap]1 mu* labor may be sav$ if a metal template ( ! requir$ size is fir/ cut f %eet brass & !n laid on ! blott+ pap]1 :i* is cut by scor+ ar\nd ! edge ( ! template ) a %>p knife4 ,illu/ration3 ,fig4 #bi4 ,section ,w9d]4 ,! pies are w\nd 9 a bobb9 or =m su* z is %[n 9 ,fig4 #bi4 ,! disks or flanges are made ( %eet brass & m\nt$ on an arbor s t ! =m may be plac$ 9 a la! or "s o!r contrivance = revolv+ x4 ,! core is bevel$ 9 ord] to facilitate ! removal ( a complet$ pie f ! w9d]4 ,! flanges ( ! w9d] are clamp$ aga9/ ! core by two nuts plac$ on ei!r side4 ,! pie is remov$ by unscrew+ "o ( ! nuts & remov+ "o ( ! flanges4 ,9 w9d+ silk cov]$ wire x is fir/ pass$ ?r\gh a mixture ( beeswax & ros9 or a ba? ( melt$ p>aff94 ,! excess ( wax is remov$ by pass+ ! wire ?r\gh a slit made 9 a pad ( pap] or by rubb+ aga9/ a piece ( felt4 ,fig4 #cj %[s su* a contrivance4 ,illu/ration3 ,fig4 #cj4 ,impregnator = ,silk ,cov]$ ,wire4 ,! wire passes f ! reel ov] an ord9>y spool d[n into ! pan ( p>aff91 out ( ! p>aff91 ov] ano!r spool1 & rubs aga9/ a piece ( felt to remove ! surplus p>aff94 ,! spools are m\nt$ ) a screw & a wa%] s t !y w turn )\t friction4 ,! wire is guid$1 :5 w9d+1 by ! f+]s4 ,if x is wrapp$ ) a piece ( felt & held betwe5 ! ?umb & =ef+] x w run )\t friction & n cut ! f+]s4 ,x is necess>y t ! wire %\ld be closely wat*$ = k9ks1 etc4 :i* w\ld cause ! wire to break4 ,(t5times ! wire is brok5 b is held toge!r by ! insulation4 ,!re=e ea* pie %\ld be te/$ = cont9uity :5 complet$4 ,?is is be/ accompli%$ by means ( a galvanomet] & batt]y4 ,all imp]fect pies %\ld be reject$1 z "o ( !m w\ld cause s]i\s tr\ble if embodi$ 9 ! coil4 ,9 sold]+ ! second>y wires1 acid mu/ n be us$ z x soon corrodes ! f9e wires4 ,ros9 is ! be/ flux = ?is purpose4 ,:5 build+ a small coil ) a lay] w9d+ x is absolutely necess>y t ! wire %\ld be w\nd on 9 smoo? ev5 lay]s4 ,9 a built-up second>y hav+ pies n great] ?an #a_/d in* 9 ?ickness su* great c>e is n necess>y4 ,illu/ration3 ,fig4 #ca4 ,me?ods ( ,connect+ ! ,second>y ,sections4 ,fig4 #ca %[s ! me?ods ( connect+ up ! pies or pancakes4 ,9 ,a1 ! inside ( "o section is connect$ to ! outside ( ! next1 & s on4 ,! maximum voltage :i* c exi/ betwe5 ! adjac5t sections 9 ?is case is equal to ! e4m4f4 g5]at$ by "o pie & is equal ?r\gh\t4 ,9 ,b1 ! coils are connect$ alt]nately inside & out4 ,! voltage ranges f z]o at ! po9ts :]e !y are connect$1 to a value equal to twice ! e4m4f4 develop$ by "o section4 ,x w\ld seem t !re w\ld be a sav+ 9 insulation space ( "o-half 9 ! fir/ case1 b x is n s s9ce ! connect+ wire passes betwe5 ! pies & !re=e ! insulation mu/ be twice z ?ick or exactly equal to t 9 ! second case4 ,! latt] me?od 7,fig4 #ca ,b7 is ! be/ & mo/ conv5i5t4 ,:5 ! pies are connect$ 9 ?is mann] ! curr5t mu/ fl[ ?r\gh alt]nate sections 9 opposite directions4 ,to accompli% ?is x is n necess>y to w9d e alt]nate coil 9 an opposite direction1 b m]ely to turn !m ar\nd & connect !m ) ! direction ( _! w9d+s rev]s$ z %[n by ! arr[s & ! bevels 9 ,fig4 #ca4 ,! connections betwe5 ! sections mu/ be v c>efully sold]$4 ,aft] ! second>y is assembl$ ! coil %\ld be plac$ 9 a tight receptacle or tank conta9+ melt$ p>aff94 ,! tank is !n connect$ to an air pump or aspirator & ! air exhau/$4 ,! dim9ution ( pressure causes any air bubbles 9 ! w9d+s to exp& & be pump$ out4 ,aft] /&+ a :ile1 ! pressure ( ! atmosph]e is readmitt$ & ! place ( ! bubbles w be occupi$ by p>aff9 :i* has be5 =c$ 9 "u pressure4 99,m\nt+499--,a coil = wireless "w is be/ m\nt$ z %[n 9 ,fig4 #cb & us$ ) an indep5d5t int]rupt]4 ,! coil may !n be plac$ "u ! op]at+ table or on ! wall1 out ( h>m's way1 & ! int]rupt] on ! table1 :]e x is h&y to ! adju/m5t ( ! op]ator4 ,illu/ration3 ,fig4 #cb4 ,coil ,case4 ,! case is simply a rectangul> h>dwood box l>ge en\gh to conta9 ! complet$ coil4 ,two b9d+ po/s m\nt$ on ! side ( ! box connect ) ! prim>y w9d+ & two on ! top ( ! box lead to ! second>y t]m9als4 ,! box is fill$ ) boil$ oil or melt$ p>aff9 & seal$ up by screw+ on ! lid4 ,if desirable1 ! second>y b9d+ po/s may be m\nt$ on ! top ( a %ort piece ( h>d rubb] rod z illu/rat$ 9 ! draw+4 ,magnetic p]meability is ! conduct+ p[] = l9es ( magnetic =ce4 ,see hy/]esis "u ,magnetic ,detector4 ,,*apt] ,v4 ,,int]rupt]s4 ,we n[ come to :at is ! greate/ s\rce ( tr\ble & annoyance 9 an induction coil1 namely ! int]rupt]4 ,too mu* importance _c be atta*$ to ?is in/rum5t1 = ^u x dep5ds l>gely ! satisfactory work+ ( ! coil4 ,! op]ation ( an induction coil & ! "p play$ by ! int]rupt] 7 fully expla9$ 9 ! *apt] on induction coils4 ,an adju/able int]rupt] is necess>y = l>ge coils1 t is1 "o n only ^: spe$ may be gov]n$1 b also ! "t & duration ( ! break4 ,illu/ration3 ,fig4 #cc4 ,simple ,int]rupt]4 ,! rapidity ( oscillation ( a me*anical int]rupt] is a v diff]5t ?+ f ! spe$ ( break4 ,! ideal spe$ ( break is in/antane\s4 ,9 wireless telegraphy1 v fa9t signals are he>d m di/9ctly 9 telephone receiv]s if ! rate ( int]ruption at ! /ation s5d+ !m is high4 ,! human e> is some:at m s5sitive to s\nds high] ?an ^? ord9>ily produc$ 9 ! telephone receiv]s ( a wireless receptor4 ,?is seems to argue ! use ( a high-spe$ int]rupt] to make & break ! curr5t4 ,b ! effect on ! coil mu/ also be consid]$4 ,9 ! fir/ place1 :]e a cond5s] is %unt$ across ! t]m9als ( ! second>y z is ! case ) a wireless transmitt]1 a high-spe$ int]rupt] w\ld be v likely to set up h>mful oscillations 9 ! second>y ( ! coil itself4 ,second1 if too fa/1 ! rise & fall ( ! second>y curr5ts w be caus$ to run into ea* o!r1 s9ce ! break w occur be=e ! prim>y curr5t has rea*$ a maximum & ! rev]se second>y curr5t has di$ away4 ,?ird1 ! diamet] ( ! core ( a wireless coil is g5]ally mu* l>g] ?an t ( ! ord9>y coil1 & if a v rapid int]rupt] is employ$ !re is n "t en\gh to prop]ly magnetize ! core be=e ! curr5t is brok54 ,f\r?1 ! /r5g? ( ! losses 9 ! core caus$ by ! eddy curr5ts & hy/]esis are proportional to ! int]ruptions 9 ! prim>y circuit & !re=e a l[ spe$ w be ! mo/ effici5t4 ,a rapid int]rupt] requires a high] voltage & amp]age ?an ! same int]rupt] run at a l[] spe$4 ,^! are "s ( ! reasons :y x is v desirable to use an atomic int]rupt] or "o s adju/able t ! rate ( ! "t & duration ( ! make & break may be closely regulat$4 ,an ideal int]rupt] is design$ to give ! longe/ "t possible aft] contact is e/abli%$ & be=e ! break occurs4 ,x does n pay to con/ruct an int]rupt] = an induction coil giv+ sp>ks up to #b in*es 9 l5g?4 ,! type ( int]rupt] 9 use on automobile coils is p]fectly well adapt$ to small coils1 & may be pur*as$ complete ) ! plat9um po9ts = z l[ a price z #a4ej4 ,! me*anical break describ$ bel[ is design$ s t v>i\s adju/m5ts are possible & x may be adapt$ to almo/ any coil4 ,s9ce x is indep5d5t1 x ne$ n be m\nt$ directly on ! coil1 b may be plac$ 9 ! position mo/ conv5i5t to ! op]ator = adju/m5t4 ,! int]rupt] w n op]ate coils well on an electromotive =ce above #cj volts1 = ! excessive voltage causes a sp>k at ! contacts :5 ! circuit is brok5 & prolongs ! decad5ce ( ! prim>y curr5t4 ,illu/ration3 ,fig4 #cd4 ,indep5d5t ,int]rupt]4 99,indep5d5t ,atomic ,int]rupt]499--,fig4 #cd illu/rates two views ( ! int]rupt]4 ,curr5t is furni%$ to ! electromagnets by a six volt batt]y indep5d5t ( ! s\rce supply+ ! coil4 ,! int]rupt] is set 9 op]ation by clos+ ! circuit break] on ! a]ial swit*4 ,:5 ! prim>y circuit ( ! transmitt] is !n complet$ by press+ ! key1 ! coil w respond imm$iately because ! int]rupt] is already 9 vibration4 ,! electromagnets 7,fig4 #ce7 are a pair ( f\r ohm telegraph s\nd] magnets4 ,a hole is bor$ 9 ! c5t] ( ! top ( ea* magnet core & ?read$ ) an #h-cb tap s t ! pole pieces may be fa/5$ !reto1 ,! %ape & dim5sions ( ^! projections1 :i* mu/ be made ( s(t iron1 are illu/rat$ 9 ,fig4 #ce4 ,illu/ration3 ,fig4 #ce4 ,details ( ,magnets4 ,a s(t iron yoke ,y1 #b #a_/b x #g_/h x #a_/d in*es1 connects ! bottom ( ! magnets & supports !m 9 an upright position4 ,an #h-cb ma*9e screw pass+ upw>d ?r\gh ! base & yoke holds !m firmly4 ,! base is pref]ably ( h>d rubb] #d x #c #a_/d x #c_/d in*es4 ,illu/ration3 ,fig4 #cf4 ,details ( ,mov+ ,p>ts4 ,! mov+ p>ts are illu/rat$ 9 ,fig4 #cf4 ,! ma9 spr+1 ,d1 is a /rip ( spr+ /eel1 #b #a_/h in*es long1 #a_/b in* wide1 & #a_/cb in* ?ick4 ,! s(t iron armature1 ,a1 is fa/5$ to ! spr+ by means ( two small #d-cf ma*9e screws4 ,m is a piece ( brass rod1 #a #a_/b in*es long1 b5t 9 ! =m ( a hook & ?read$ ) a #d-cf die to screw 9 a simil>ly ?read$ hole 9 ! back ( ! armature ,a4 ,! hook$ portion ( ,m is fitt$ ) a small piece ( h>d rubb] rod1 ,r1 to insulate x :]e x comes into contact ) ! spr+1 ,g4 ,! spr+1 ,d1 c>ries a second hook1 ,e1 rivet$ to ! c5t] ( ! spr+ #a #e_/h in*es f ! l[] end4 ,! hook1 :i* is ab\t #c_/h in* long1 passes ?r\gh a hole 9 ! top ( ! spr+1 ,f1 & engages x s t x is set 9 op]ation by ! vibratory motion ( ! spr+1 ,d4 ,! spr+1 ,f1 is #a #c_/d in*es long1 #e_/af in* wide1 & ir #a_/fd in* ?ick4 ,x c>ries a plat9um rivet #c_/d in* f its l[] end4 ,! spr+1 ,g1 is #b #a_/b in*es long1 #e_/af in* wide & #a_/fd in* ?ick4 ,a heavy plat9um rivet is fa/5$ #b #a_/d in*es f ! l[] end4 ,an elongat$ hole1 #a_/d in* long & #c_/af in* wide1 p]mits ! hook1 ,m1 to pass ?r\gh ! op5+4 ,a #e_/cb in* hole1 #a #a_/d in*es f ! bottom1 all[s ! adju/+ screw to pass ?r\gh & make contact ) ! plat9um rivet on ! spr+1 ,f4 ,two rectangul> pieces ( brass1 ,o1 #a #a_/d x #a_/b x #e_/af in*es are fa/5$ to ! base to support ! spr+s4 ,illu/ration3 ,fig4 #cg4 ,details ( ,/&>d & ,screws4 ,! /&>d1 ,u1 support+ ! adju/+ ?umbscrews is a piece ( #c_/h-;in* brass1 #b #a_/b in*es high4 ,x tap]s f #a #a_/b in*es at ! bottom to #c_/d in* at ! top4 ,a hole #b #a_/d in*es f ! bottom is ?read$ ) a #aj-cb tap to receive ! ?umbscrew1 ,b4 ,a second hole #a #a_/d in*es f ! base is ?read$ ) an #h-cb tap to fit ! adju/+ screw1 ,s4 ,bo? ( ! adju/+ ?umbscrews c>ry heavy plat9um po9ts4 ,! /&>d is held upright to ! base by means ( two ma*9e screws pass+ ?r\gh ! base4 ,a #c_/cb in* brass rod #a #c_/d in*es long is ?read$ to fit a hole 9 ! top ( ! armature4 ,a slid+ weight1 ,w1 may be clamp$ 9 any position on ! rod by means ( a ?umb-screw4 ,rais+ or l[]+ ! position ( ! weight decreases or increases ! natural p]iod ( vibration ( ! int]rupt]4 ,screw+ ! hook1 ,m1 9 or out s z to %ort5 or l5g!n x1 decreases or increases ! ratio ( ! make to ! break4 ,illu/ration3 ,fig4 #ch4 ,diagram ( ,connections = an ,indep5d5t ,int]rupt]4 ,fig4 #ch %[s a diagram ( ! connections ( ! int]rupt]4 ,! /&>d1 ! ?umbscrew1 ,b1 & ! spr+1 ,g1 =m "p ( ! prim>y circuit ( ! induction coil4 ,! /&>d1 ! ?umbscrew1 ,s1 ! spr+1 ,f1 & ! electromagnets are plac$ 9 s]ies ) a six-volt batt]y & connect$ to ! circuit break] on ! a]ial swit*1 s t :5 ! swit* is ?r[n 9 position = transmitt+1 ! int]rupt] w be set 9 op]ation4 ,a cond5s] mu/ be %unt$ across ! l>g] contacts ( ! int]rupt] 9 ord] to ha/5 ! demagnetization ( ! core ( ! induction coil & create a high] e4m4f4 9 ! second>y4 ,! cond5s] mu/ be suit$ 9 size to ! induction coil ) :i* ! int]rupt] is to be us$ & s ! foll[+ table is app5d$ to s]ve z a guide4 ,! cond5s]s are built up ( alt]nate %eets ( t9 foil & p>aff9$ pap]4 ,connections are made to ! %eets by means ( t9 foil /rips :i* project out alt]nately f opposite sides z 9 ! illu/ration4 ,! pap] %\ld be ab\t two in*es l>g] ea* way s z to leave a "o in* m>g9 on all sides ( ! t9 foil4 ,illu/ration3 ,fig4 #ci4 ,con/ruction ( a ,pap] ,cond5s]4 ,:5 ! alt]nate %eets ( t9 foil & pap] h all be5 assembl$1 ! cond5s] is w>m$ s z to s(t5 ! p>aff94 ,x is !n plac$ betwe5 two flat bo>ds & subject$ to great pressure 9 a lett] press or a vice4 ,! capacity ( a press$ cond5s] is (t5 sev]al times t ( a cond5s] ( ! same dim5sions b n press$4 99,m]cury ,int]rupt]s499--,! m]cury turb9e int]rupt] is "o ( ! mo/ conv5i5t & successful breaks 9 use4 ,! con/ruction is su* t a /ream ( m]cury is made to play aga9/ a numb] ( saw %ap$ metal tee?4 ,a spiral worm t]m9at+ 9 a nozzle at ! top is rapidly revolv$ by an electric motor4 ,! l[] end ( ! tubul> worm dips 9 a m]cury res]voir1 s t :5 ! spiral is revolv$ ! m]cury is caus$ by c5trifugal action to rise 9 ! tube & be ?r[n out 9 ! =m ( a jet at ! upp] end4 ,:5 ! revolv+ jet /rikes "o ( ! metal tee?1 ! circuit is clos$ & ! curr5t fl[s f ! m]cury jet into ! tee?4 ,:5 ! m]cury jet passes betwe5 ! op5+s betwe5 ! tee?1 ! circuit is int]rupt$4 ,by rais+ & l[]+ ! saw tee? s t ! m]cury /rikes ei!r ! l[] or upp] "p ( !m1 ! ratio betwe5 ! make & break may be made small] or l>g]4 ,by regulat+ ! spe$ ( ! motor driv+ ! jet1 ! numb] ( int]ruptions may be v>i$ f #aj to #aj1jjj p] second4 ,! bottom & sides ( ! m]cury res]voir are ribb$ to prev5t ! m]cury f atta9+ a rot>y motion4 ,a some:at simpl] & m easily con/ruct$ type ( m]cury int]rupt] consi/s ( a h>d rubb] disk hav+ a brass rod runn+ ?r\gh f ! p]iph]y to ! c5t]1 :]e x connects ) ! %aft4 ,! l[] edge ( ! disk dips at an angle 9 a m]cury ba? & is rapidly revolv$ by an electric motor4 ,:5 ! rod is "u ! surface ( ! m]cury1 ! circuit is made ?r\gh ! m]cury to ! rod4 ,! circuit is brok5 :5 ! rod is above ! surface4 ,! m]cury is cov]$ ) a lay] ( alcohol1 :i* prev5ts excessive sp>k+ & makes a quick] break4 ,an int]rupt] ( ?is k9d :5 run by a motor ( ! magnetic attraction type is exce$+ly simple4 ,! break ( any ( ! m]cury type int]rupt]s :5 prop]ly adju/$ is mu* quick] ?an ! hamm] spr+ break & gives ?ick] sp>ks4 ,aft] ! m]cury has be5 9 use a:ile x becomes *urn$ up into small globules ( a black color1 b may be easily clean$ & re/or$ = use by %ak+ up ) "s /rong sulphuric acid4 ,c>e mu/ be tak5 t ! m]cury is p]fectly dry & free f acid be=e replac+ 9 ! int]rupt]4 99,electrolytic ,int]rupt]s499--,fig4 #dj %[s a diagram ( a ,wehnelt int]rupt]4 ,! ca?ode or negative electrode is a lead plate imm]s$ 9 dilute sulphuric acid4 ,! anode is a piece ( plat9um wire plac$ 9 a porcela9 tube & project+ ?r\gh a small hole 9 ! bottom1 s t only a v small surface ( ! wire is expos$ to ! liquid4 ,:5 a /rong electrical curr5t is pass$ ?r\gh ! acid electrolyte1 ! curr5t is v rapidly int]rupt$ by ! =mation ( gases on ! small plat9um electrode4 ,! spe$ ( ! int]rupt] is v>iable ?r\gh great ranges by mov+ ! plat9um electrode up or d[n & *ang+ ! am\nt ( surface expos$ to ! liquid4 ,! only disadvantage ( ?is int]rupt] is t ! electrolyte soon becomes heat$1 & unless ! int]rupt] is provid$ ) a wat] jacket or "s device = cool+1 ! bubbles ( gas d n =m freely4 ,a pot5tial ( at lea/ #dj volts is requir$ to op]ate a ,wehnelt or o!r electrolytic break4 ,illu/ration3 ,fig4 #dj4 ,w5helt & ,simon ,electrolytic ,int]rupt]s4 ,a ,wehnelt int]rupt] may easily be made by seal+ a plat9um wire 9 a glass tube4 ,x is well to make sev]al su* tubes ) ! plat9um project+ f "o-sixte5? to "o-qu>t] ( an in*4 ,! diff]5t tubes w ea* h a diff]5t spe$ ( int]ruption1 & "o %\ld be pick$ out :i* seems to be mo/ suitable = ! coil ^u te/+4 ,connection to ! plat9um wire is e/abli%$ by fill+ ! tube ) m]cury & dipp+ a wire 9 x4 ,fig4 #dj also %[s a diagram ( a ,simon electrolytic int]rupt]4 ,x consi/s ( a vessel conta9+ dilute sulphuric acid & divid$ into two p>ts by a ?9 porcela9 diaphragm hav+ a small hole 9 ! c5t]4 ,a lead electrode dips into ea* ( ! divisions4 ,! int]ruption is caus$ by exce$+ a c]ta9 curr5t d5sity 9 ! small hole at ! diaphragm4 ,^u ! passage ( ! curr5t ! liquid is s heat$ t x becomes vaporiz$4 ,! vapor is a poor conductor to l[ voltages & s ! curr5t is brok54 ,imm$iately ^u ! cessation ( ! curr5t1 ! vapor cond5ses & ! circuit is e/abli%$ aga94 ,?is cycle repeats itself ) a spe$ dep5d+ ^u ! size ( ! ap]ture & ! am\nt ( curr5t fl[+4 ,a crude =m ( ?is type ( int]rupt] may be made by heat+ ! end ( a te/ tube 9 a p9 flame1 & !n bl[+ on ! op5 end ( ! tube s z to bur/ ! s(t glass & =m a small hole4 ,sev]al su* te/ tubes %\ld be prep>$ hav+ holes v>y+ f #a_/cb to #a_/h ( an in* 9 diamet]4 ,! "o :i* gives ! be/ results ^u trial is select$ = use4 ,a numb] ( holes 9 a s+le tube1 if n too _m or too l>ge 9 diamet]1 increases ! effici5cy & ! spe$ ( int]ruption4 ,! tube %\ld be imm]s$ 9 a glass j> conta9+ dilute sulphuric acid4 ,"o lead electrode is plac$ inside ( ! te/ tube & ! o!r outside4 ,x makes no diff]5ce :i* way ! curr5t fl[s ?r\gh ?is int]rupt]4 ,! ,caldwell int]rupt] is a modification ( ! ,simon type 9 :i* ! size ( ! ap]ture is made adju/able by means ( a po9t$ glass rod :i* may be rais$ or l[]$ 9 ! hole & ! spe$ ( int]ruption v>i$4 ,an int]rupt] ( ! te/ tube type z describ$ above may be modifi$ to ?is =m by locat+ ! hole directly 9 ! c5t] ( ! bottom ( ! tube & ins]t+ 9 x a h>d glass rod :i* has be5 drawn out to a po9t4 ,electrolytic int]rupt]s d n require any cond5s] connect$ across ! break4 ,illu/ration3 ,fig4 #da4 ,con/ruction ( ,electrolytic ,int]rupt]s4 ,fig4 #da %[s 9 section m sub/antial =ms ( bo? ! ,wehnelt & ,simon-,caldwell int]rupt]s4 ,! conta9]s are ord9>y #e x #g in* batt]y j>s4 ,!y are fitt$ ) cov]s made ( two ?icknesses1 ,c & ,b1 ( #c_/d-;in* wood4 ,! upp] piece1 ,c1 is #f in*es 9 diamet]1 :ile ! "u "o %\ld fit snugly into ! int]ior ( ! j>4 ,! wood mu/ be boil$ 9 p>aff9 to protect x f ! action ( ! acid4 ,a slit is made 9 ! left-h& side ( bo? cov]s = ! passage ( a lead electrode1 ,l1 #a in* wide & #a_/d in* ?ick4 ,! upp] end ( ! electrode is b5t ov] & fitt$ ) a b9d+ po/4 ,illu/ration3 ,fig4 #db4 ,details ( ,electrolytic ,int]rupt]s4 ,! me*anism = adju/+ ! int]rupt]s is ! same 9 bo? cases4 ,! dim5sions are indicat$ 9 ,fig4 #db4 ,a brass yoke1 ,y1 is m\nt$ on ! cov] 9 ! position %[n4 ,a #a_/b-;in* hole is bor$ ?r\gh ! upp] "p ( ! yoke & a piece ( brass tub+1 ,s1 #a in* long sold]$ 9 a v]tical position 9 ! hole4 ,a #a_/d-;in* ?read$ brass rod passes ?r\gh ! tube1 #e4 ,a groove is mill$ 9 ,a along its entire l5g? & engages a p9 9 ! wall ( ,s4 ,! rod is ?us enabl$ to slide up & d[n 9 ! tube b is prev5t$ f revolv+4 ,a fib] head1 ,h1 is fitt$ ) a brass sleeve or bu%+ 9 its c5t]4 ,! bu%+ %\ld fit tightly into ! fib] head & is ?read$ to fit ! rod1 ,a4 ,! electrode may !n be c>efully rais$ or l[]$ by revolv+ ! head4 ,! tube1 ,v1 = ! ,simon-,caldwell int]rupt] is a h>d glass te/ tube4 ,a #a_/h-;in* hole is bl[n 9 ! bottom ( ! tube4 ,a h>d glass rod1 ,g1 is drawn out to a po9t & fa/5$ to ! l[] end ( ! rod1 ,a1 by means ( a %ort l5g? ( flexible rubb] tub+1 ,r4 ,! tube1 ,n1 = ! ,wehnelt break is made f a piece ( h>d rubb] tub+ #f in*es long1 hav+ a bore ( ,j in*4 ,illu/ration3 ,fig4 #dc4 ,electrolytic ,int]rupt]4 ,! l[] end is fitt$ ) a sp>k plug porcela94 ,! porcela9 mu/ fit ! tube tightly & n leak4 ,! electrode1 ,p1 is a piece ( brass wire :i* w j pass ?r\gh ! hole 9 ! porcela94 ,! upp] end ( ! electrode1 ,p1 is sold]$ or fa/5$ o!rwise to ! l[] end ( ! rod1 ,a4 ,a small hole1 h1 %\ld be made 9 ! tubes1 ,n & ,v1 above ! level ( ! electrolyte 9 ! j>4 ,:5 ! int]rupt] is 9 op]ation ! electrolyte gradually rises 9 ! tubes1 & w\ld corrode ! l[] end ( ,a if x 7 n able to pass out ?r\gh ! v5ts4 ,9 ! ,simon-,caldwell int]rupt]1 a /rip ( lead passes f ! b9d+ po/ m\nt$ on ! foot ( ! yoke d[n inside ( ! te/ tube4 ,! size ( ! hole 9 ! tube is regulat$ by revolv+ ! fib] head s t ! glass po9t$ rod w be ins]t$ 9 or )drawn f ! hole4 ,! frequ5cy ( ! int]ruption w also dep5d some:at on ! conc5tration ( ! acid solution4 ,x is !re=e be/ to />t ) a weak solution & add acid sl[ly until x is ( ! prop] /r5g?4 ,,*apt] ,,vi4 ,,trans=m]s4 ,:]e alt]nat+ curr5t is available 9 comm]cial wireless telegraph /ations1 ! induction coil has be5 gradually sup]s$$ by ! m mod]n trans=m] = *>g+ ! oscillation cond5s]4 ,s9ce ! trans=m] is less exp5sive to con/ruct ?an an induction coil capable ( transmitt+ ! same di/ance1 x is favor$ by _m amateur exp]im5t]s4 ,a "o qu>t] kil[att trans=m] has a s5d+ range ( ov] #ej miles :5 us$ ) a prop]ly con/ruct$ a]ial ab\t #hj feet high4 ,?is is probably ! size be/ suit$ to ! av]age private in/allation4 ,! second>y ( a wireless trans=m] seldom develops pot5tials exce$+ #ae1jjj to #bj1jjj volts1 :ile ^? ( an induction coil range f #a #e1jjj to #cjj1jjj volts4 ,h[ev]1 ! /r5g? ( ! second>y curr5t ( a trans=m] is s mu* great] ?an t ( an induction coil1 t m p[]ful & p5etrat+ waves are develop$4 ,= ^! reasons a trans=m] is always rat$ by its output 9 watts or kil[atts r ?an by ! sp>k l5g? produc$ at ! second>y t]m9als4 ,! sp>k ( a "o qu>t] kil[att trans=m] is only #j4be to #j4ej ( an in*1 :ile ! sp>k ( a "o half kil[att trans=m] may be ! same l5g? b /ill repres5t m en]gy4 ,!re are two di/9ct types ( trans=m]s 9 use1 kn[n z ! op5 & clos$1 accord+ly :e!r ! core is /raight l ! core ( an induction coil or 9 ! =m ( a holl[ rectangle4 ,! op5 core type is us$ 9 ! gov]nm5t /ations & by ! ,unit$ ,wireless ,telegraph ,co4 ,x is ! simpl] & m easily con/ruct$ ( ! two1 b is also less effici5t & requires t m mat]ial be exp5d$ to br+ x up to a def9ite rat+4 ,9 pr9ciple x is simply an induction coil op]at$ on alt]nat+ curr5t m9us ! int]rupt] & cond5s]4 ,9 view ( ! great] curr5ts employ$1 ! w9d+s mu/ be l>g] & heavi] ?an ^? ( ! induction coil to prev5t heat+4 ,be=e comm5c+ ! con/ruction ( a trans=m] "o %\ld read ! *apt] on induction coils & use ! same c>e emphasiz$ !re 9 reg>d to build+ coils4 99,op5 ,core ,trans=m]499--,! trans=m] describ$ bel[ w transmit f #bj to #ge miles & consume ab\t #cjj watts on ! no volt #fj cycle alt]nat+ curr5t4 ,! core is #af in*es long & #b in*es 9 diamet]4 ,x is built up ( s(t iron wires 9 ! same mann] z if x 7 ! core ( an induction coil4 ,! prim>y is compos$ ( two lay]s ( ,no4 #ad d\ble cotton cov]$ ,b4 ,s4 gauge magnet wire4 ,! prim>y is #ad in*es long & is wrapp$ ) a lay] ( micanite clo? #c_/h in* ?ick to sep>ate x f ! second>y w9d+4 ,x is nev] advisable to use %ellack$ cotton clo? z insulation4 ,:5 cotton is dri$ & %ellack$1 x is at fir/ a good insulator1 b soon becomes capable ( absorb+ moi/ure4 ,%ellac c>bonizes at a l[ temp]ature1 & if a trans=m] or coil hav+ any ( ?is sort ( insulation ent]+ into its con/ruction is ov]heat$1 ! insulation is liable to become a conductor4 ,micanite clo? is ! be/ insulation = trans=m]s4 ,! dielectric /r5g?s ( ! diff]5t =ms ( micanite are %[n by ! foll[+ table4 ,! second>y is w\nd 9 t5 sections ov] ! micanite insulation4 ,ea* section is #f in*es 9 diamet] & #a #a_/d in*es ?ick & is w\nd ) ,no4 #cj ,b4 ,s4 s+le silk cov]$ wire4 ,! sections are sep>at$ by disks ( blott+ pap] #a_/h in* ?ick & #g in*es 9 diamet]1 treat$ z describ$ 9 ,*apt] ,,iv4 ,! complet$ trans=m] %\ld be plac$ 9 a box & cov]$ ) oil4 99,a ,"o ,qu>t] ,kil[att ,clos$ ,core ,trans=m]499 ,! simple/ =m ( a clos$ core trans=m] consi/s ( two indep5d5t coils ( insulat$ wire w\nd ^u an iron r+4 ,:5 an alt]nat+ curr5t is pass$ ?r\gh "o ( ! coils1 kn[n z ! prim>y1 x g5]ates a magnetic flux 9 ! iron core4 ,! l9es ( =ce pass+ ?r\gh ! core induce 9 ! second>y coil an electromotive =ce ! magnitude ( :i* is 9 ne>ly ! same ratio to ! prim>y induc+ electromotive =ce z ! numb] ( turns ( wire 9 ! second>y is to ! numb] ( turns 9 ! prim>y4 ,= example1 if x is desir$ to raise ! pot5tial ( ! no volt alt]nat+ curr5t to #bb1jjj volts1 ! numb] ( turns 9 ! second>y ( ! trans=m] mu/ be at lea/ #bjj times ! numb] 9 ! prim>y4 ,a circul> r+ ( iron wire pres5ts sev]al !oretical advantages z a trans=m] core b x w\ld be difficult to =m & aft]w>ds place ! w9d+s 9 position4 ,! core is !re=e usually 9 ! =m ( a holl[ rectangle1 built up ( v ?9 %eets or lam9ations ( s(t iron c>efully insulat$ f "o ano!r by a coat ( v>ni%4 ,if ! core 7 solid or ! sep>ate lam9ations n insulat$ f "o ano!r1 heavy curr5ts1 kn[n z eddy curr5ts1 w\ld be set up 9 ! iron & cause heat+4 ,a consid]able loss 9 ! effici5cy ( ! trans=m] w\ld also result4 ,"o half ( bo? ! second>y & ! prim>y w9d+s ( a prop]ly design$ trans=m] are plac$ on opposite sides or legs ( ! core 9 ord] to r$uce ! magnetic leakage & increase ! effici5cy4 ,! only difficulty involv$ 9 su* con/ruction is ! prop] insulation ( ! prim>y f ! second>y1 b if c>eful att5tion is giv5 to ?is po9t no difficulty w be exp]i5c$4 99,core499--,! dim5sions & me?od ( assembl+ ! core lam9ations are indicat$ by ,fig4 #dd4 ,long /rips are cut f s(t ,russian or ,sw$i% /ovepipe iron4 ,! /rips1 :i* are #a #c_/d in*es wide are !n cut up into %ort l5g?s1 "o half ( :i* are #g #c_/d in*es long & ! o!r half #d #c_/d in*es4 ,en\gh are cut to =m two piles ( ea* size #a #c_/d in*es high :5 compress$4 ,! complet$ core w !n =m a holl[ rectangle #i #a_/b x #f #a_/b x #a #c_/d in*es4 ,illu/ration3 ,fig4 #dd4 ,assembly & ,dim5sions ( ,core4 ,! /rips mu/ be dipp$ 9 "s good insulat+ v>ni% su* z ,p4 ,b4 comp\nd & ?or\ghly dri$ be=e !y are assembl$4 ,bo? legs 7! longe/ sides7 are laid on a table ) ! alt]nate ends ov]lapp+ z %[n by ,a & ,b 9 ,fig4 #dd4 ,aft] ! %ort pieces ,c & ,d h be5 slipp$ betwe5 ! ov]lapp+ ends ! :ole core is squ>$ up4 ,! /rips ,d are !n c>efully remov$ & "o end ( ! core ?us left op5 until all ! w9d+s are 9 place4 ,?ree or f\r lay]s ( well v>ni%$ l95 clo? are w\nd tightly ov] ! legs prep>atory to w9d+ on ! prim>y4 99,prim>y499--,f\r fib] heads1 ,h1 #d #c_/d in*es squ>e1 #a_/b in* ?ick & hav+ a squ>e hole #a #g_/h x #a #g_/h in*es cut 9 ! c5t] are requir$4 ,"o ( ! fib] heads is plac$ on ea* end ( ! assembl$ leg z %[n 9 ,fig4 #dh4 ,illu/ration3 ,fig4 #de4 ,fib] ,head & ,sep>ator4 ,! prim>y w9d+ is w\nd 9 six lay]s1 #d #a_/b in*es long1 ?ree lay]s on ea* leg4 ,ab\t ?ree p\nds ( ,no4 #af ,b4 ,s4 gauge d\ble cotton cov]$ magnet wire are requir$ = ! w9d+4 ,! t]m9als ( ! two halves ( ! prim>y are l$ ?r\gh ! fib] heads at ! same end ( ! trans=m]4 ,! w9d+s are n to be c>ri$ close up to ! fib] heads b beg9 & end ab\t #a_/d in* f !m1 s t ! rema9+ space may be fill$ by w9d+ 9 a /rip ( micanite clo? #a_/d in* wide4 ,! prim>y & second>y w9d+s are sep>at$ by a /rip ( micanite clo? #e in*es wide1 w\nd ov] bo? ( ! prim>y w9d+s close up to ! heads until a lay] #a_/b in* ?ick is =m$4 99,second>y499--,! =m on :i* ! second>y sections are w\nd is illu/rat$ 9 ,fig4 #df4 ,all ! p>ts are cut out ( wood except ! %aft & are made ( ! dim5sions indicat$4 ,if ! c5t] ( ! =m is slightly tap]$ x w greatly facilitate ! removal ( ! complet$ sections4 ,sixte5 sections are requir$4 ,:5 remov$ f ! w9d] !y w be 9 ! =m ( holl[ squ>es #d #a_/b x #d #a_/b x #g_/af in*es4 ,illu/ration3 ,fig4 #df4 ,section ,=m4 ,ab\t t5 p\nds ( ,no4 #cd ,b4 ,s4 gauge silk cov]$ wire are requir$ to w9d ! sections4 ,cotton cov]$ wire mu/ n be us$ to avoid exp5se1 because ) x a suffici5t numb] ( second>y turns _c be secur$ to br+ ! second>y curr5t up to ! prop] voltage4 ,by obs]v+ explicitly ! in/ructions & precautions giv5 bel[ no tr\ble w be exp]i5c$ 9 h&l+ enamel$ wire & =m+ ! sections4 ,! =m %\ld be plac$ 9 a la! *uck or "s o!r ma*9e :i* is conv5i5t & :]eby ! =m may be rapidly revolv$ "u ! control ( ! op]ator4 ,saw slots are cut 9 ! wood5 flanges & ! c5t] ( ! =m z %[n 9 ! illu/ration s t silk ?reads may be pass$ "u & ar\nd ! complet$ section & ti$ s t a possible cave 9 ( ! wire is prev5t$4 ,aft] ty+ up ! section %\ld be remov$ f ! =m by unscrew+ ! nut & tak+ (f ! flange4 ,illu/ration3 ,fig4 #dg4 ,me?ods ( ,connect+ ,sections4 ,:5 w9d+ ! wire x mu/ be v c>efully wat*$ = loops or k9ks & only be laid on 9 ev5 lay]s4 ,x mu/ also be borne 9 m9d t enamel$ wire _c be z tightly w\nd z fib] cov]$ wire = reasons h]et(ore expla9$4 ,9 case ! wire becomes brok51 x mu/ be smoo?ly splic$ & sold]$4 ,d n "u any consid]ation use acid z a flux or heat ! wire ) a flame4 ,acid w corrode ! f9e wire1 & ! flame w badly oxidize or melt x4 ,use a %ort piece ( ,no4 #h ,b4 ,s4 gauge t9n$ copp] wire set 9 a small file h&le z a sold]+ iron1 & ros9 z a flux4 ,p>aff9 "s silk b9d+ tape su* z dressmak]s use & wrap ! jo9t ) a small piece4 ,! sections z !y are remov$ f ! w9d] mu/ be tap$ & !n c>efully m>k$ ) an arr[ :i* po9ts 9 ! direction ( ! w9d+4 ,fig4 #dg illu/rates ! two me?ods ( connect+ up ! sections4 ,x w be notic$ 9 ! second me?od t ! arr[ d5ot+ ! direction ( w9d+ po9ts d[n on e alt]nate section4 ,?is does n indicate necess>ily t e alt]nate section is w\nd 9 an opposite direction f ! o!r1 b t !y h m]ely be5 turn$ ar\nd s t ! arr[s come on a rev]se side ( ! core & po9t 9 an opposite direction4 ,?is precaution mu/ be tak5 9 ord] t ! curr5t w fl[ ?r\gh all ! sections1 & is made necess>y because ! inside t]m9al ( "o section is connect$ to ! inside t]m9al ( ! adjac5t section & ! outside t]m9al ( t section is connect$ to ! outside t]m9al ( ! next adjac5t section4 ,! fir/ me?od1 ,a1 illu/rat$ 9 ,fig4 #dd1 is less complicat$ & does n require ?is rev]sal1 b = v>i\s reasons is n to be recomm5d$ 9 place ( ,b4 ,eight ( ! complet$ & tap$ sections are plac$ on ea* leg ( ! trans=m]1 ) "o ( ! fib] sep>ators betwe5 ea* pair z 9 ,figs4 #dh & #di4 ,:5 ea* leg has be5 completely assembl$1 sold] all ! second>y t]m9als toge!r s z to connect z 9 ,fig4 #dg4 ,illu/ration3 ,fig4 #dh4 ,assembly ( ,leg4 ,!n place ! rema9+ fib] head1 ,s1 on ea* ( ! legs & f9i% assembl+ ! core by slipp+ 9 ! end /rips ,d4 ,squ>e ! core up p]fectly true & fa/5 by f\r fib] /rips ,m1 ,fig4 #di1 #i #c_/d in*es long1 #a #c_/d in*es wide & #a_/b-;in* ?ick4 ,! /rips are plac$ 9 ! position %[n 9 ,fig4 #df & a hole ,p bor$ 9 ! end ( ea*4 ,f\r #a_/d-;in* bolts1 two ( :i* are #c in*es long & two #c #a_/b in*es1 pass ?r\gh ! holes 9 ! /rips1 s t :5 ! nuts are screw$ on ! core is clamp$ firmly4 ,! two long] bolts are plac$ at ! same end ( ! trans=m]4 ,illu/ration3 ,fig4 #di4 ,trans=m] ) ,"o ,second>y remov$4 ,! t]m9als ( ! prim>y lead out to f\r b9d+ po/s m\nt$ on ! fib] /rips4 ,! pill>s :i* support ! second>y b9d+ po/s are fib] rods1 #a in* 9 diamet] & #b in*es long4 ,! l[] end ( ea* is bor$ & tapp$ to fit ! upp] ends ( ! long] bolts :i* clamp ! fib] /rips toge!r4 ,an insulat+ %ield mu/ be plac$ betwe5 ! two second>y w9d+s to prev5t sp>ks f jump+ across4 ,a piece ( fib] #e x #e x #a_/h in*es w s]ve nicely = ?is purpose4 ,if ! prim>y w9d+s are plac$ 9 s]ies ! trans=m] w consume ab\t #cjj watts4 ,:5 ! trans=m] is plac$ 9 a box & ! box fill$ ) "s boil$ amb] petroleum1 ! w9d+s may be connect$ 9 p>allel & ! trans=m] w consume ab\t #ejj watts4 ,x w !n transmit ov] #ajj miles provid+ ! a]ial is at lea/ #ajj feet high4 ,! wir+ connections are diagram$ 9 ,fig4 #ej4 ,a v>iable inductance or reactance coil is connect$ 9 s]ies ) ! prim>y circuit to /eady ! curr5t1 z expla9$ 9 ! p>agraph "u reactance4 ,a reactance suitable = ?is trans=m] may be con/ruct$ by w9d+ two lay]s ( ,no4 #ab ,b4 ,s4 gauge cotton cov]$ wire1 six in*es long1 ar\nd a holl[ wood5 tube made ( cig> box wood4 ,! core is built up ( s(t %eet iron to =m a rectangle #h x #a #c_/d x #a #c_/d in*es :i* w j slide 9 & out ( ! tube4 ,! w9d+s %\ld be ab\t six in*es long4 ,illu/ration3 ,fig4 #ej4 ,wir+ ,diagram4 ,five half-gallon ,leyd5 j>s =m ab\t ! "r capacity = ! second>y ( ! trans=m] :5 ! w9d+s are 9 s]ies4 ,twice t numb] mu/ be us$ :5 ! w9d+s are 9 p>allel4 ,! second>y sections mu/ always be kept 9 s]ies1 z o!rwise ! voltage w\ld n be high en\gh to prop]ly *>ge ! cond5s]4 ,con/ruction ( a #b-,k4,w4 ,trans=m]4 99,core499--,/rips #b #a_/b in*es wide are cut f s(t %eet iron4 ,"o half ( !m %\ld be #aa #a_/b in*es long & ! o!r half #f #a_/b in*es4 ,en\gh are cut to make two piles ( ea* size #b #a_/b in*es high4 ,bo? sides 7! longe/ /rips7 ( ! core are built up ) ! ends ov]lapp+ z 9 ,fig4 #da4 ,! ends 7! %ort pieces7 are !n slipp$ betwe5 ! ov]lapp+ ends ( ! long /rips & ! :ole core squ>$ up4 ,! complet$ core %\ld h a cross section ( #b #a_/b in*es squ>e & =m a holl[ rectangle #h x #ad in*es4 ,! /rips ( iron mu/ be dipp$ 9 ,p4 ,b4 insulat+ v>ni% & dri$ be=e !y are assembl$4 99,prim>y499--,f\r fib] heads #f in*es squ>e1 #a_/b in* ?ick & hav+ a hole #b #a_/b in*es squ>e are made4 ,"o ( ^! is plac$ on ! core legs z %[n by ,fig4 #dh4 ,two or ?ree lay]s ( well v>ni%$ l95 are w\nd ov] ! core prep>atory to w9d+ ! prim>y4 ,room mu/ be left = ! o!r head to be plac$ on ! opposite end aft] ! w9d+s are all 9 place4 ,! prim>y consi/s ( #ajj d\ble turns ( ,no4 #ab ,b4 ,s4 gauge d\ble cotton cov]$ magnet wire4 ,fifty ( ! d\ble turns are w\nd on ea* leg4 ,! f\r t]m9als ( ! prim>y are l$ out ?r\gh ! fib] heads4 ,c>e %\ld be tak5 to di/+ui% !m f ea* o!r s t !y may be id5tifi$ :5 ! trans=m] is complet$4 ,! prim>y is !n w\nd ) a /rip ( micanite or empire clo? #h in*es wide until x measures #d in*es squ>e ov] all4 99,second>y499--,! second>y coils1 :i* are eight 9 numb]1 are w\nd on a =m #d in*es squ>e & #a #a_/b in*es betwe5 ! flanges4 ,! con/ruction ( ! =m is simil> to t %[n 9 ,fig4 #df b is l>g]4 ,! slots are also necess>y "h s t ! complet$ section may be ti$ up4 ,ab\t t5 p\nds ( ,no4 #cj ,b4 ,s4 gauge s+le silk cov]$ wire are requir$ to w9d ! second>y4 ,! sections are w\nd 9 smoo? ev5 lay]s until !y are six in*es 9 outside diamet]4 ,!y are !n ti$ up & remov$ f ! w9d]4 ,! sections are sep>at$ by %eets ( fib] #f #a_/b in*es squ>e on ! outside1 #a_/b in* ?ick1 hav+ a hole #d in*es squ>e cut 9 ! c5t]4 ,! sections are all connect$ 9 s]ies & ! t]m9als sold]$ to /rips ( copp]4 ,aft] ! second>y coils are all 9 place & connect$1 ! fib] head is slipp$ on ! end ( ! leg4 ,!n ! %ort l5g?s ( ! core1 :i* _h be5 pull$ out aga9 aft] squ>+ ! core up1 are slipp$ into place4 ,! core is squ>$ up aga9 & fa/5$ toge!r by bor+ a #c_/h-;in* hole completely ?r\gh ! core at ea* corn]4 ,two /rips ( fib] #ab x #b #a_/b x #a_/b in*es are bor$ ) correspond+ holes 9 _! ends4 ,^! /rips are plac$ at ! end ( ! trans=m]1 on top ( ! core1 & #a_/d-;in* bolts pass$ ?r\gh ! holes 9 ! fib] & ! core4 ,! bolts are wrapp$ ) micanite clo? :]e !y pass ?r\gh ! core1 & an insulat+ wa%] is plac$ "u ! nuts1 s t ! iron core lam9ations are n electrically connect$4 ,! nuts are tight5$ until ! core is held firmly toge!r4 ,! fib] /rips also s]ve z insulat$ supports = ! b9d+ po/s4 ,! copp] t]m9als ( ! second>y lead to two b9d+ po/s m\nt$ on two fib] or h>d rubb] pill>s #a in* diamet] & #d in*es high4 ,! rods are arrang$ z expla9$ 9 ! section "u ! head+ ( a #a_/d-,k4,w4 trans=m]4 ,! trans=m] is design$ = use on a #fj-;cycle #aaj-volt curr5t4 ,x may be us$ on #bbj volts if ! two prim>y coils are connect$ 9 s]ies4 ,:5 ! prim>ies are 9 s]ies1 & ! trans=m] is us$ on ! #aaj-volt curr5t1 x w deliv] a voltage ( ab\t #ab1jjj at ! second>y4 ,) ei!r prim>y alone ! voltage w be ab\t #ab1jjj1 & ) bo? 9 p>allel ab\t #be1jjj4 ,x w !n deliv] a v heavy curr5t at ! second>y & draw f ! l9e ab\t #bj amp]es 9 ! prim>y4 ,if us$ ) a prop] tun+ helix1 cond5s] & a]ial1 ! trans=m] is capable ( s5d+ ab\t #cjj miles "u favorable conditions4 ,if ! trans=m] is to be us$ = long p]iods at a "t1 x is be/ to place x 9 a tight wood5 box #ah in*es squ>e & #ab in*es deep4 ,! box is !n fill$ ) boil$ l9se$ oil or amb] petroleum4 ,a rheo/at or imp$ance & reactance coil %\ld be plac$ 9 s]ies ) ! trans=m] to regulate ! curr5t & also to prev5t arc+ across ! sp>k gap4 99,reactance499--,9 ,*apt] ,i1 ! lag & lead ( a circuit 7 expla9$ 9 connection ) tun+4 ,?is is a prop]ty ( e alt]nat+ circuit & is br\ght to our notice aga9 9 ! trans=m] :i* *>ges ! cond5s]4 ,! curr5t develop$ by a trans=m] is a lead+ curr5t1 s9ce ! in/antane\s values ( ! curr5t d n correspond to ! proportionate values ( ! voltage supply+ ! curr5t4 ,9 ord] to =ce ! curr5t values ( ! *>g+ curr5t to correspond ) ! voltage x is necess>y to produce a lag4 ,?is is accompli%$ by means ( an adju/able reactance 9 s]ies ) ! prim>y ( ! trans=m]4 ,a reactance or inductance suitable = ! #b-,k4,w4 trans=m] may be made by build+ up a coil 9 ! same mann] z describ$ "u ! head+ ( ! ,j-,k4,w4 trans=m]4 ,! reactance w h to be some:at l>g] on acc\nt ( ! heavi] curr5ts4 ,! core is built up ( %eet iron to measure #b #a_/b x #b #a_/b x #aj in*es :5 complet$4 ,! coil is w\nd ar\nd a wood5 =m & is compos$ ( ab\t #ajj turns ( ,no4 #h ,b4 ,s4 gauge d\ble cotton cov]$ magnet wire4 ,by v>y+ ! am\nt ( core ins]t$ 9 ! holl[ coil ! en]gy may be adju/$ z desir$4 ,illu/ration3 ,fig4 #ea4 ,clapp-,ea/ham #a_/d-,k4,w4 ,trans=m]4 ,fig4 #ea illu/rates ! #a_/d-,k4,w4 trans=m] manufactur$ by ! ,clapp-,ea/ham ,company4 ,! core is s con/ruct$ t a small metal tongue ( s(t iron projects f "o side ( ! core t[>ds ! opposite side betwe5 ! w9d+s1 b is sep>at$ f ! opposite side by a small air gap4 ,sev]al objects are accompli%$ by ?is tongue1 :i* gives rise to magnetic leakage2 ! inductance ( ! prim>y is increas$ !reby to su* an ext5t t ! trans=m] is self-controll+1 s t x may be connect$ directly to ! s\rce ( alt]nat+ curr5t supply ( ord9>y comm]cial frequ5cies & pot5tial1 & ! curr5t fl[+ 9 ?is circuit be regulat$ by v>y+ ! numb] ( turns 9 ! prim>y coil4 ,z ?is magnetic leakage gives rise to a loose c\pl+ effect1 ! prim>y & second>y circuits may be br\ght into resonance by plac+ a suitable capacity across ! second>y t]m9als4 ,?is condition ( resonance br+s ! p[] factor to a mat]ially high] p]c5tage4 ,:ile ! p[] factor ( ! op5 or clos$ core trans=m] is seldom above #ej1 ?is type ( trans=m] has a p[] factor ( #hj to #ij :5 us$ ) a suitable cond5s]4 ,illu/ration3 ,fig4 #eb4 ,unit$ ,wireless ,motor-,g5]ator set = supply+ ,alt]nat+ ,curr5t to ! ,trans=m]4 ,ano!r po9t ( consid]able advantage is ! almo/ entire fre$om f arc+ at ! sp>k gap :5 ?is type ( trans=m] is us$4 ,! sp>k gap is connect$ directly across ! second>y t]m9als ( ! trans=m] & ! cond5s]4 ,! prim>y turns ( ! helix & ! sp>k gap are connect$ 9 s]ies4 ,:5 ! trans=m] is 9 op]ation1 ?is cond5s] be+ across ! second>y1 ! trans=m] is 9 resonance & ! cond5s] is *>g$ to su* a po9t t x w jump ! sp>k gap4 ,at ! in/ant t ! sp>k passes1 ! second>y ( ! trans=m] is practically %ort circuit$ ?r\gh ! sp>k gap4 ,z ?is circuit is n[ clos$ & ! cond5s] out ( circuit1 ! second>y circuit ( ! trans=m] is no long] 9 resonance & ! en]gy imm$iately drops (f1 de/roy+ at once ! t5d5cy = an arc to =m4 ,z soon z ! sp>k has pass$1 ! cond5s] ( c\rse comes 9 to play & ! condition ( resonance be+ ree/abli%$ ! same process is repeat$4 ,! ,clapp-,ea/ham ,company h made application = a pat5t on any trans=m] employ+ ?is or any simil> con/ruction = use 9 *>g+ a cond5s]4 ,,*apt] ,,vii4 ,,oscillation ,,cond5s]s ,,& ,,leyd5 ,,j>s4 ,a cond5s] consi/s ( two conduct+ surfaces sep>at$ by an insulator or dielectric4 ,fig4 #ec %[s a diagram ( a simple cond5s] 9 :i* ,a & ,b are two t9foil %eets sep>at$ by a %eet ( glass1 ,c4 ,illu/ration3 ,fig4 #ec4 ,simple ,cond5s]4 ,if ,a is connect$ by means ( a wire to a /atic ma*9e a positive *>ge w collect on ! glass at ,a & induce a negative *>ge at ,b1 s t if ,a & ,b are connect$ to a small sp>k gap ! *>ge w leap ! gap 9 ! =m ( a sp>k4 ,:5 a cond5s] dis*>ges ?r\gh a coil ( wire1 ! dis*>ge consi/s ( a l>ge numb] ( exce$+ly rapid oscillations or surg+s4 ,! fir/ passage ( curr5t m ?an empties ! cond5s] & x becomes *>g$ 9 ! opposite direction1 t is1 ! conduct+ coat+s *ange _! pol>ity4 ,a rev]se dis*>ge !n occurs :i* also ov]/eps itself & ! oscillations ?us g on b become rapidly weak] until !y die completely4 ,! "t consum$ 9 ! dis*>ge may h be5 only a fraction ( a second1 b dur+ t %ort p]iod ! curr5t p]haps oscillat$ sev]al ?\s& times4 ,if a cond5s] is dis*>g$ ?r\gh a conductor ( high resi/ance ! dis*>ge passes out sl[ly1 & dies away gradually 9 "o direction )\t oscillat+4 ,"o ( ! fundam5tal equations ( wireless telegraphy is !re=e t !re w be oscillations 9 a circuit if ! resi/ance 9 ohms is n great] ?an ! squ>e root ( f\r times ! inductance 9 h5ries divid$ by ! capacity ( ! cond5s] 9 micr(>ads4 ,! capacity or ! ability ( a cond5s] to /ore electricity dep5ds ^u ! area & =m ( ! conduct+ surfaces1 ! ?ickness ( ! dielectric betwe5 !m1 & a factor kn[n z ! specific inductive capacity ( ! dielectric4 ,! unit ( capacity is call$ ! f>ad & is def9$ z ! cond5s] :i* w\ld be rais$ to a pot5tial ( "o volt by a *>ge ( "o amp]e fl[+ = "o second4 ,a cond5s] ( su* a capacity is1 because ( its enorm\s size1 impractical to con/ruct1 & ! unit ord9>ily us$ is !re=e ! micr(>ad1 or "o million? ( a f>ad4 ,capacity may be calculat$ f ! foll[+ =mula3 ,capacity equals ,k7,a_/,d71 :]e ,k equals a con/ant dep5d+ ^u ! specific inductive capacity ( ! dielectric1 ,a ! total area ( t9foil & ,d ! ?ickness ( ! dielectric4 99,leyd5 ,j>s499--,transmitt+ cond5s]s 9 a wireless telegraph /ation usually take ! conv5i5t =m ( a j>1 coat$ inside & out ) t9foil & kn[n z a ,leyd5 j>4 ,! j>s %\ld be ( good ,bohemian or ,j5a h>d glass & coat$ ) t9foil only = ab\t ?ree-qu>t]s ( _! height1 z o!rwise ! dis*>ge is liable to pass ov] ! top4 ,! t9foil mu/ be ?ick to avoid bli/]+1 & is /uck to ! glass ) %ellac v>ni%4 ,! bli/]+ ( ,leyd5 j>s is a s]i\s fault1 = :5 ?is condition exi/s1 ! capacity is !reby alt]$ to su* an ext5t t ! p]iod ( ! clos$ circuit may be suffici5tly alt]$ to ?r[ ! sy/em out ( tune & decrease ! radiation ( en]gy4 ,consid]able exp5se may be sav$ if ! glass j>s are pur*as$ & coat$ by ! amateur4 ,! be/ j>s are ^? import$ f ,g]many1 :i* h wide m\?s s t !y may be easily coat$ inside ) t9foil4 ,illu/ration3 ,fig4 #ed4 ,leyd5 ,j>4 ,! j>s mu/ be ?or\ghly clean$ & dri$ be=e !y are coat$4 ,give ! inside a ?or\gh bru%+ ov] ) %ellac v>ni%1 & be=e x is dry1 c>efully ins]t ! t9foil & press x smoo?ly aga9/ ! glass4 ,! outside ( ! j> is treat$ & coat$ 9 ! same mann]4 ,! inside & outside ( ! bottom are also coat$ by cutt+ ! t9foil 9 circul> pieces & %ellack+ !m on4 ,illu/ration3 ,fig4 #ee4 ,a]ial ,swit*4 ,! :ole upp] "p ( ! j> is giv5 "o or two coats ( %ellac 9 ord] to prev5t ! collection ( moi/ure & bru% dis*>g+4 ,a wood5 plug fitt$ 9 ! top ( ! j> supports a brass rod1 t]m9at+ at ! l[] end 9 a *a9 or spiral spr+ :i* connects ) ! inn] coat+4 ,:5 tr\ble is exp]i5c$ because ( an imp]fect contact betwe5 ! coat+ & ! *a9 or rod1 a lay] ( brass fil+s an in* or two deep plac$ 9 ! bottom ( ! j> w rem$y ! difficulty4 ,! upp] end ( ! rod usually t]m9ates 9 a small brass ball or a b9d+ po/4 ,! wood5 plug or cov] is dri$ 9 an ov5 to expel all moi/ure & !n boil$ 9 p>aff94 ,small ,leyd5 j>s may be v conv5i5tly made f six-in* te/ tubes & m\nt$ 9 a rack s t ! capacity ( ! cond5s] w be adju/able by remov+ "o or m ( ! tubes4 ,an ord9>y te/ tube rack su* z is us$ 9 *emical laboratories s]ves v well = ?is purpose4 ,! tubes %\ld be connect$ 9 p>allel1 t is1 all ! outside coat+s toge!r & all ! inside coat+s toge!r4 ,figs4 #ee & #ef illu/rate cond5s]s ( ?is type :i* are on ! m>ket4 ,! tubes are all sep>ately removable s t ! capacity may be adju/$4 ,illu/ration3 ,fig4 #ef4 ,amco ,oscillation ,cond5s]4 99,glass ,plate ,cond5s]s499--,glass plate cond5s]s (f] sev]al advantages ov] ,leyd5 j>s & are com+ into wide use4 ,!y are n s bulky or exp5sive &1 above all1 d n bli/]4 ,plate cond5s]s are (t5 plac$ 9 a rack & made adju/able by means ( movable contacts4 ,mu* ! bett] plan is to place ! plates 9 oil1 z ?is elim9ates all corona or bru% dis*>ges & mu* %>p] tun+ is r5d]$ possible4 ,! conta9] is usually a tight wood5 box fill$ ) oil or p>aff9 aft] ! plates are 9 place4 ,x is impossible to /ate ! size ( cond5s] suitable = induction coils ( a giv5 p[] or sp>k l5g?1 because _m factors su* z inductance1 l5g? ( a]ial1 etc41 :i* diff] 9 v>i\s /ations1 influ5ce ! capacity4 ,a cond5s] ( conv5i5t size suitable = coils or small trans=m]s consum+ f #bej to #cjj watts is t describ$ bel[4 ,x is ab\t ! prop] size = ! small op5 core & #a_/d-,k4,w4 clos$ core trans=m]s1 describ$ 9 ! la/ *apt]4 ,illu/ration3 ,fig4 #eg4 ,clapp-,ea/ham ,oscillation ,cond5s]4 ,! glass plates may be secur$ by remov+ ! emulsion f old #h x #aj in* photograph plates4 ,hot wat] w s(t5 ! gelat9 on ! plates s t x may be v easily scrap$ (f4 ,tw5ty-f\r plates ( ?is size are requir$4 ,! t9foil is cut #h x #h in*es1 s t an in* m>g9 is left on all sides4 ,! alt]nate %eets are connect$ toge!r by heavy t9foil or ?9 copp] foil /rips4 ,! cond5s] %\ld be plac$ 9 a conv5i5t siz$ wood5 box & p\r$ full ( p>aff94 ,! plate cond5s] %[n 9 ,fig4 #eg is ( 4#jb micr(>ad capacity4 ,! cond5s] is m\nt$ 9 a pla9 wood5 box ) sev]al b9d+ po/s br\ght out1 s t ! capacity may be v>i$ by connect+ 9 v>i\s sections4 ,! cond5s] is manufactur$ & design$ by ! ,clapp-,ea/ham ,company = use ) ! trans=m] illu/rat$ 9 ,fig4 #ea4 ,x is v necess>y to h ! transmitt+ cond5s] adju/able s t its capacity may be v>i$1 = ! prop] value dep5ds ^u ! wave l5g?1 sp>k frequ5cy1 p[] & p]si/5cy ( ! wave tra94 ,:5 ! cond5s] capacity is too small ! sp>k w be some:at flam+ l an arc1 & ! pot5tial to :i* ! a]ial is *>g$ w be l[4 ,if too mu* capacity is us$ ! sp>k w be v irregul> & int]mitt5t4 ,illu/ration3 ,fig4 #eh4 ,me?ods ( ,v>y+ ,capacity4 ,fig4 #eh %[s cond5s]s connect$ 9 s]ies & 9 p>allel & a comb9ation ( ! two4 ,two cond5s]s ( equal capacity connect$ 9 p>allel h twice ! capacity ( "o1 :ile 9 s]ies !y w h only "o-half ! capacity ( ei!r4 ,?is may be o!rwise /at$ z ! capacity 9 s]ies is equal to ! reciprocal ( ! sum ( ! reciprocals ( _! capacities sep>ately4 ,by ?is means ( connect+ ei!r 9 s]ies or 9 p>allel almo/ any desir$ adju/m5t ( capacity may be br\ght ab\t4 ,(t5times a high voltage may be divid$ betwe5 two cond5s]s by plac+ !m 9 s]ies & ?us us+ !m safely on a voltage :i* w\ld rupture ei!r "o alone4 ,= example1 two cond5s]s built = #bj1jjj volts & to be us$ on #cj1jjj volts c\ld be made to p]=m ?is duty safely & only und]go a pot5tial ( #ae1jjj volts1 :i* is a l>ge m>g9 ( safety4 ,x is obvi\s t if ! capacity ( ! circuit 7 to rema9 con/ant1 f\r cond5s]s connect$ up 9 s]ies-p>allel w\ld be necess>y4 ,9 case ( sev]al ,ley d5 j>s or cond5s]s connect$ up 9 a transmitt+ circuit1 ! leads or conduct+ wires connect+ ! v>i\s units %\ld all be ( z ne>ly ! same l5g? z x is possible to h !m4 ,! resi/ance ( metallic conductors to high frequ5cy curr5ts is sev]al times _! normal resi/ance to con/ant curr5ts4 ,! l>g] ! diamet] ( ! wire ! great] is ?is ratio4 ,?is increase ( resi/ance is due to ! fact t ! high frequ5cy curr5ts p]meate wires only a v %ort di/ance4 ,9 ! case ( copp]1 ! dep? is only ab\t "o ?ree-hundr$? ( an in* & ) o!r metals mu* less4 ,!re=e x is advisable to use z leads & conductors ( l>ge cond5s]s1 /r&$ wires or flat ribbons ( %eet copp] 9 ord] to pres5t m surface & (f] less resi/ance ?an solid conductors ( an equal cross sectional area4 ,iron mu/ nev] be us$1 z its resi/ance to ^! curr5ts is ov] fifty times t ( copp]4 ,aft] connections are once e/abli%$ betwe5 ! j>s or ! cond5s] units1 !y _c be alt]$ nor ! capacity *ang$ )\t re tun+ ! circuits aft]w>ds4 ,,*apt] ,,viii4 ,,sp>k ,,gaps ,,or ,,oscillators4 ,! oscillator or sp>k gap is "o ( ! mo/ important yet (t5 ! mo/ poorly adju/$ "p ( a wireless /ation4 ,to obta9 a good oscillatory dis*>ge ) little damp+ x is necess>y t ! resi/ance ( ! circuit %\ld be kept l[1 & s9ce ! greate/ "p ( ! resi/ance is 9 ! sp>k gap x w\ld appe> z if ?is mu/ be v %ort4 ,:ile !re are reasons = keep+ x %ort !re are on ! o!r h& v good reasons :y x %\ld n be made too %ort1 & ! prop] l5g? %\ld be a sort ( compromise to be det]m9$ by exp]im5t4 ,if ! gap is too %ort1 ! dis*>ge w =m an arc & ! only oscillations tak+ place w be ^? correspond+ to ! frequ5cy ( ! *>g+ curr5t4 ,p[] consumption is also 9 favor ( a long gap1 s9ce x causes ! induction coil or trans=m] to draw less curr5t f ! l9e4 ,ano!r argum5t 9 favor ( a long gap is ! fact t ! cond5s] is *>g$ to a high] voltage & m en]gy /or$ up1 :i* makes a great] di/ance ( transmission possible4 ,b z /at$ above 7& !re always is a t5d5cy = ! amateur op]ator to op5 out 8 gap z long z ! sp>ks w cont9ue to jump /eadily7 ! dis*>ge w n oscillate b w m]ely set up a unidirectional curr5t4 ,!re exi/s a prop] gap l5g? = a giv5 circuit :i* w cause t circuit to emit a maximum am\nt ( en]gy & :i* may be det]m9$ accurately only by means ( a hot-wire ammet] plac$ 9 ! a]ial circuit4 ,! prop] gap l5g? is !n indicat$ by ! maximum deflection ( ! met]4 ,! correct adju/m5t ( ! gap may be approximat$ by ! exp]i5c$ op]ator4 ,if too %ort1 ! sp>k w be hiss+ & flam+ & is 9 extreme cases r$ or yell[ color$4 ,x %\ld be l5g!n$ out until x is ?ick & :ite & a slight increase 9 s\nd is not$4 ,! sp>k %\ld n be1 z commonly ?\ght1 /r+y & crackl+4 ,arc+ is (t5 caus$ by insuffici5t cond5s] capacity 9 ! circuit4 ,b if ! capacity is increas$ to rem$y ! arc+1 ! gap l5g? %\ld also be increas$ or o!rwise ! pot5tial ( ! cond5s] may n be suffici5tly rais$ to p]mit a disruptive dis*>ge to take place4 ,illu/ration3 ,fig4 #ei4 ,sp>k ,gaps4 ,! be/ sp>k gap = use ) a small untun$ transmitt]1 mak+ use ( nei!r tun+ helix nor cond5s]1 is %[n at ! left 9 ,fig4 #ei4 ,x consi/s ( two brass balls support$ on suitable d\ble b9d+ po/s4 ,! balls t5d to ?ick5 ! sp>k & make x m disruptive ?an if x pass$ betwe5 rods or po9ts4 ,! balls also increase ! pot5tial requir$ to leap ! gap )\t increas+ its l5g? & p]mit ! a]ial to become m highly *>g$ be=e a dis*>ge takes place4 ,= ?is reason ! balls or knobs mu/ always be kept free f small r\gh spots or po9ts by frequ5t poli%+4 ,silv] has "s peculi> prop]ty :i* makes x ! mo/ effici5t mat]ial = a sp>k gap1 b its co/ prohibits its use & s brass or z9c1 :i* are next 9 ord]1 is g5]ally us$4 ,! type ( gap illu/rat$ at ! "r 9 ,fig4 #ei is v conv5i5t & effici5t = small tun$ transmitt]s employ+ coils ( l[ p[]4 ,illu/ration3 ,fig4 #fj4 ,sp>k ,gap4 ,! z9c tips are pieces ( #c_/h-;in* z9c batt]y rod #c_/d in* long4 ,!y are bor$ & ?read$ to fit a pair ( brass rods #a_/h in* diamet] & #b #a_/b in*es long4 ,! rods are support$ by two d\ble b9d+ po/s & are fitt$ ) two pieces ( h>d rubb] rod #a_/b in* diamet] & #a in* long to s]ve z h&les4 ,if desirable "o ( ! rods & b9d+ po/s may be ?read$ s t ! adju/m5t ( ! gap c be accompli%$ by revolv+ ! h&le & screw+ ! gap 9 or out4 ,a gap ( ! size & type j describ$ w\ld n be suitable 9 connection ) a l>ge trans=m] or an induction coil4 ,! heavy dis*>ge ( su* p[]ful in/rum5ts w\ld v rapidly heat ! small brass p>ts & corrode or ev5 melt ! z9c4 ,! sp>k gap su* z is %[n 9 ,fig4 #ei may be us$ ) a v l>ge coil or ! two kil[att trans=m] if ! same proportions are kept & x is made "o-half aga9 z l>ge4 ,us+ ! dim5sions %[n 9 ! figure1 ! sp>k gap is suit$ to ei!r ! op5 core or ! #a_/d & #a_/b kil[att trans=m]s4 ,two pieces ( h>d rubb] rod1 #c_/d in* diamet] & #b in*es long s]ve z ! /&>ds4 ,?ree grooves #a_/h in* wide1 #a_/h in* deep & #a_/h in* ap>t bett] ! appe>ance & r$uce ! liability ( leakage b are n necess>y4 ,two holes #b in*es ap>t are bor$ 9 ,s1 a /rip ( brass #c x #c_/d x #a_/d in*es4 ,two screws pass ?r\gh ^! holes into ! rubb] /&>ds ,,bb & hold ,s firmly 9 position4 ,! end ( ,s is b5t d[n at "r angles & bor$ to receive a b9d+ po/4 ,a hole is bor$ 9 ,s halfway betwe5 ! /&>ds & tapp$ to receive a ?read$ brass rod #b in*es long & #a_/d in* diamet]4 ,! l[] ends ( ! h>d rubb] /&>ds are ea* bor$ & tapp$ to receive a screw :i* fa/5s !m to ! base4 ,! electrodes are z9c or brass cyl9d]s #c_/d in* diamet] & #e_/h in* long4 ,! upp] electrode is adju/able by means ( a knurl$ h>d rubb] head #b in*es diamet] & #a_/b in* ?ick4 ,! l[] "o is fa/5$ to a brass plate #b in*es long1 #a in* wide & #a_/h in* ?ick4 ,"o end ( ! plate is fitt$ ) a b9d+ po/4 ,! base is a piece ( h>d rubb] #e #a_/b x #c in*es x #c_/d in*4 ,,*apt] ,,ix4 ,,transmitt+ ,,helixes4 ,! transmitt+ helix or tun+ coil supplies ! great] "p ( ! inductance :i* is s necess>y = ! production ( electrical oscillations 9 ! transmitt+ circuit4 ,x consi/s m]ely ( a few turns ( heavy copp] or brass wire w\nd 9 a helix ar\nd a =m4 ,two or m movable contacts p]mit v>i\s am\nts ( ! inductance to be ins]t$ 9 ! op5 or clos$ circuits4 ,! tun+ helixes describ$ 9 ?is *apt] are (f]$ pr9cipally to s]ve z guides4 ,!y h be5 design$ z c>efully z possible to suit ! transmitt]s = :i* !y are recomm5d$4 ,!re are factors1 su* z ! a]ial1 etc41 :i* v>y greatly 9 /ations ( ! same rat$ p[] & make x be/ to det]m9e ! l5g? ( ! helix by actual exp]im5t4 ,a c]ta9 am\nt ( inductance is necess>y 9 ! clos$ circuit = ! production ( electrical oscillations & to transf] en]gy to ! op5 circuit4 ,inductance beyond t necess>y to receive en]gy f ! clos$ circuit less5s ! radiation & makes x necess>y to increase ! p]iod ( ! op5 circuit by add+ wires to ! a]ial4 ,! op5 & clos$ circuits ( a tun+ helix con/itute an oscillation trans=m]1 & ! two circuits if !y are v close toge!r or int]tw9$ are said to be closely c\pl$4 ,:5 sep>at$ or f> ap>t !y are loosely c\pl$4 99,closely ,c\pl$ ,helix499--,fig4 #fa illu/rates a closely c\pl$ tun+ helix1 suitable = ord9>y induction coils giv+ sp>ks up to #c or #d in*es 9 l5g?4 ,! heads ( ! helix are circul> pieces ( h>d wood #a in* ?ick & #ab in*es 9 diamet]4 ,six rectangul> not*es are made at equal di/ances along ! edges ( ! heads4 ,six uprights #c_/d x #a_/b in* & #h #c_/d in*es long are fa/5$ 9 ! not*es ) small r\nd head$ brass screws s t ! heads are sep>at$ a di/ance ( #f #c_/d in*es4 ,grooves are cut 9 ! outside face ( ea* ( ! uprights at a di/ance ( #g_/h in* ap>t4 ,! wire =m+ ! helix is #a_/d in* brass4 ,brass wire is spr+y & reta9s its %ape bett] ?an copp]4 ,ab\t tw5ty-two feet w be requir$4 ,! wire is w\nd 9 ! grooves 9 ! uprights & held 9 place by a few d\ble po9t$ tacks plac$ judici\sly4 ,! adjac5t turns ( wire w !n h a sep>ation ( ab\t #e_/h in*4 ,illu/ration3 ,fig4 #fa4 ,closely ,c\pl$ ,helix4 ,! helix is rais$ above ! level ( ! op]at+ b5* or table by ?ree small feet fa/5$ to ! "u head1 #abj degrees ap>t4 ,illu/ration3 99,plate ,,iii4 ,transmitt+ ,circuits499 ,if x is desir$ to use ?is helix ) ! "o qu>t] ,k4,w4 trans=m]1 ! diamet] ( ! wire %\ld be increas$ to #e_/af in*4 ,! two ,k4,w4 trans=m] w require sev5 turns ( #a_/b-;in* h>d drawn brass wire two feet 9 diamet]4 ,illu/ration3 ,fig4 #fb4 ,prague ,transmitt+ ,helix4 ,:5 sett+ up a transmitt+ /ation1 x is a good plan to coil up a long piece ( ! wire to be us$ on ! helix ar\nd a r\gh =m4 ,! adjac5t turns %\ld be ! same di/ance ap>t z !y are to be on ! f9i%$ in/rum5t4 ,tune up ! /ation ) ?is improvis$ helix & asc]ta9 ! am\nt ( inductance requir$4 ,x is !n easy to design a helix conta9+ ! prop] am\nt ( wire4 ,f\r or five feet extra %\ld be includ$ to all[ pl5ty ( range 9 case x is ev] necess>y to make any *anges 9 ! a]ial or cond5s]4 ,illu/ration3 ,fig4 #fc4 ,closely ,c\pl$ ,tun+ ,circuit4 ,plate ,,iii illu/rates ! transmitt+ circuits ( ! v>i\s comm]cial sy/ems4 ,! circuit us$ w det]m9e ! numb] ( b9d+ po/s & movable clips necess>y4 ,fig4 #fc gives ! diagram ( a v good circuit4 99,loosely ,c\pl$ ,helix994 ,! heads ( ! prim>y coil ( ! loosely c\pl$ helix illu/rat$ 9 ,fig4 #fd are circul> pieces ( h>d wood #a in* ?ick & #ah in*es 9 diamet]4 ,six uprights #c_/d x #a_/b in* & #aa in*es long are set into not*es 9 ! upp] head & fa/5$ to ! base s t ! space betwe5 ! heads = w9d+ ! wire is #aj in*es4 ,illu/ration3 ,fig4 #fd4 ,loosely ,c\pl$ ,transmitt+ ,helix & ,contact ,clip4 ,a squ>e wood5 pill> #a #a_/b x #a #a_/b in*es & #cb in*es long passes ?r\gh a squ>e hole #a #a_/b x #a #a_/b in*es 9 ! c5t] ( ! heads & projects #bj in*es above ! upp] "o4 ,! heads ( ! second>y coil are ea* #ab in*es 9 diamet]4 ,! di/ance betwe5 !m is also #ab in*es4 ,a squ>e hole #a #a_/b in*es x #a #a_/b in*es 9 ! c5t] ( ea* ( ! heads p]mits ! :ole second>y coil to slide up & d[n on ! pill>4 ,sev]al #a_/d in* holes bor$ #a in* ap>t 9 ! pill> admit a small peg ( ! same diamet]4 ,! c\pl+ betwe5 ! two coils is v>i$ by *ang+ ! height ( ,s above ,p & ins]t+ ! peg to hold ! upp] coil 9 position4 ,! prim>y w9d+ ( ! trans=m] %\ld consi/ ( ab\t #bj turns #ae in*es 9 diamet]1 & may range 9 size ( wire f ,no4 #b to ,no4 #h ,b4 ,s4 gauge4 ,! second>y is #aj in*es 9 diamet] & w require ab\t #dj turns ( ,no4 #aj to ,no4 #af ,b4 ,s4 gauge4 ,! l>ge/ sizes ( wire are = ! "o-qu>t] & "o-half ,k4,w4 trans=m]s :ile ! small] sizes are be/ suit$ to small induction coils4 ,fig4 #fd also illu/rates a clip = mak+ connections to ! turns ( ! helix4 ,! h&le is a piece ( h>d rubb] rod #b #a_/b in*es long & #e_/h in* 9 diamet]4 ,a saw slot #a in* deep is cut d[n ! c5t] ( "o end4 ,two /rips ( spr+ brass #b in*es long1 #e_/h in* wide & #c_/fd in* ?ick are b5t z %[n 9 ! illu/ration4 ,! /raight ends are slipp$ 9 ! slot 9 ! h&le & clamp$ toge!r by bor+ a hole & pass+ a ma*9e screw ?r\gh4 ,! upp] end may be fitt$ ) a nut or a b9d+ po/ to facilitate connection4 ,flexible copp] ribbons or /r&$ wire %\ld be ! only conductor us$ = ! tun+ leads4 ,illu/ration3 ,fig4 #fe4 ,loosely ,c\pl$ ,transmitt+ ,circuit4 99,tun+ a ,transmitt]499--,fig4 #fb %[s a complete wir+ diagram ( a transmitt] ) a hot wire ammet] ins]t$ 9 ! a]ial circuit4 ,to tune su* a transmitt] place bo? contacts ,a & ,b toge!r on a turn ( wire ne> ! c5t] ( ! helix4 ,set ! transmitt] 9 op]ation by press+ ! key & move bo? contacts toge!r along ! v>i\s turns ( wire until ! met] %[s a maximum read+4 ,!n v>y ,b alone until ! read+ is /ill high]4 ,%ift+ ,a v>ies ! inductance 9 ! clos$ circuit & ,b t ( ! op5 circuit4 ,fig4 #fe illu/rates ! circuit ( a loosely c\pl$ transmitt]4 ,to tune su* a circuit x is necess>y to connect a small ne$le sp>k gap betwe5 ! a]ial & ! gr\nd4 ,illu/ration3 ,fig4 #ff4 ,unit$ ,wireless ,helix1 ,sp>k ,gap & ,cond5s]4 ,a suitable sp>k gap = ?is purpose may be made ( two d>n+ ne$les m\nt$ 9 d\ble b9d+ po/s4 ,set ! clips1 ,a & ,b1 at ! c5t] turns ( _! respective coils4 ,press ! key to op]ate ! transmitt] & adju/ ! clip1 ,a1 until ! be/ sp>k is obta9$ 9 ! small ne$le gap4 ,!n adju/ ,b until ! sp>k is /ill bett]4 ,if sev]al wires seem to give ! same results1 move ! second>y a little fur!r away f ! prim>y & try aga94 ,aft] secur+ ! be/ sp>k x is possible to obta91 remove ! ne$le gap1 :i* is only us$ 9 te/+4 ,! hot wire ammet] %\ld !n be plac$ 9 s]ies ) ! a]ial4 ,by sl[ly & c>efully adju/+ ! clips & v>y+ ! c\pl+1 ! hot wire ammet] w indicate ! prop] tune4 ,! second>y ( ! loosely c\pl$ tun+ coil produces a kick back effect on ! prim>y1 due to induction1 & unless ! two coils are some:at sep>at$1 ! wave emitt$ f ! transmitt] w h m ?an "o hump & a p]son receiv+ ! wave w be able to tune x 9 on two places on 8 tun+ coil4 ,a loosely c\pl$ tun+ coil does n radiate s mu* en]gy z a closely c\pl$ helix1 b w1 :5 prop]ly tun$1 emit a wave :i* is n s highly damp$4 ,!re=e z f> z di/ance is conc]n$ ! loosely c\pl$ type is p]haps ! mo/ effici5t4 ,,*apt] ,x4 ,,keys4 ,,! keys us$ 9 wireless "w diff] f ^? us$ 9 comm]cial wire telegraphy 9 be+ mu* heavi] & /rong]1 s z to conduct & break ! heavi] curr5ts )\t heat+4 ,:]e v p[]ful curr5ts mu/ be brok5 ! contacts ( ! key usually op]ate "u oil or 9 ! magnetic field ( a pair ( electromagnets4 ,9 o!r cases a small key is us$ to op]ate a heavy relay4 ,9 ! =m] type a metal arm projects d[nw>d f ! lev] ( an ord9>y ,morse telegraph key into a comp>tm5t fill$ ) oil4 ,! arm is provid$ ) a plat9um po9t :i* makes contact ) ano!r simil> po9t on ! bottom ( ! comp>tm5t1 s t ! break is made "u oil & ! key rema9s cool & does n arc4 ,9 ! second =m ! same result is accompli%$ by a magnetic bl[\t4 ,! bl[\t is m]ely an electromagnet connect$ 9 s]ies ) ! key & its poles at "r angles to ! contacts ( ! key4 ,:5 ! circuit is brok5 ! magnetic field ext+ui%es ! arc :i* t5ds to =m betwe5 ! contacts ( ! key4 ,an ord9>y ,morse key may be us$ ) coils op]at$ on batt]ies if !y d n give m ?an a f\r-in* sp>k4 ,l>g] coils or trans=m]s1 especially if !y are op]at$ on ! #aaj-volt curr5t1 require a heavi] key4 ,:]e an ord9>y ,morse key is us$ ) a #c-;in* or #d-;in* coil x is a v good plan to provide an auxili>y conductor1 "o end ( :i* is fa/5$ to ! metal base & ! o!r end to ! adju/+ screw on ! back ( ! lev]4 ,a piece ( flexible lamp cord is suitable = ?is purpose4 ,?is precaution saves ! pivots ( ! key f heat+ & possible burn+ by heavy curr5ts4 ,illu/ration3 ,fig4 #fg4 ,morse ,key fitt$ ) ,ext5sion ,lev]4 ,! mo/ conv5i5t me?od is to fit up an old ,morse key 9 ! mann] %[n 9 ,fig4 #fg4 ,! lev] is ext5d$ by a piece ( alum9um or brass #f in*es long & #e_/af in* ?ick4 ,! exact %ape & ! dim5sions are indicat$ 9 ! illu/ration4 ,! ext5sion lev] is provid$ ) a #a_/b-;in* r\nd brass or nickel /eel contact #g_/h in* long4 ,! l[] end ( ! contact is bor$ & tapp$ to receive a %ort ma*9e screw4 ,! o!r contact is a simil> piece project+ d[nw>ds f a small arm fa/5$ to ! top ( a /&>d #a_/b in* diamet] & #b in*es long4 ,! arm is a /rip ( brass #a_/b in* wide1 #a_/d in* ?ick1 & #a #a_/b in*es long1 fa/5$ to ! top ( ! /&>d ) a ma*9e screw4 ,! brass /&>d is held 9 an upright position by means ( a small ma*9e screw :i* passes ?r\gh ! base4 ,a wire connects ) ?is screw to a heavy b9d+ po/ m\nt$ on ! base4 ,connection is made ) contact on ! ext5sion lev] by means ( a piece ( heavy flexible lamp cord1 :i* also runs to a b9d+ po/ m\nt$ on ! base4 ,! contact is insulat$ f ! ext5sion lev] by means ( two mica insulat+ wa%]s & a bu%+4 ,avoid runn+ ! connection to ! base ( ! key s t ! curr5t mu/ pass ?r\gh ! be>+s4 ,! contacts %\ld be fil$ until !y are p]fectly flat & squ>e across & make contact ov] _! entire surface4 ,:5 c>efully con/ruct$ a key ( ?is type w c>ry )\t heat+ almo/ any curr5ts 9 rea* ( ! amateur op]ator & :i* 8 induction coil or trans=m] w /&4 ,illu/ration3 ,fig4 #fh4 ,wireless ,key4 ,! plans & dim5sions = a heavi] key are %[n 9 ,fig4 #fh4 ,a wood5 patt]n ( ! base & be>+s is made & tak5 to a brass f\ndry :]e a ca/+ 9 brass may be secur$4 ,! patt]n %\ld be ( ! same %ape & size z ! f9i%$ article repres5t$ 9 ! figure4 ,x is giv5 a slight tap] s t x may be easily )drawn f ! s& mold4 ,! brass ca/+ is f9i%$ up squ>e & smoo? by gr9d+ on an em]y :eel or by c>eful fil+4 ,! lev] is a piece ( brass rod #a_/b in* squ>e & #f #a_/b in*es long4 ,"o end is fitt$ ) an ord9>y h>d rubb] ,morse key knob4 ,! knurl$ nuts & ?umbscrews are ( ! same size z ^? us$ on an ord9>y key1 & may be pur*as$ f an electrical supply h\se4 ,illu/ration3 ,fig4 #fi4 ,unit$ ,wireless ,type ,key4 ,! pivot is a piece ( #c_/af in* r\nd /eel #a in* long1 & passes ?r\gh ! lev] #a #a_/b in*es f ! re> end4 ,! ends are gr\nd or turn$ to %>p po9ts & re/ 9 be>+s =m$ by bor+ a recess 9 ! ends ( ! ?umbscrews4 ,! ?umbscrews pass ?r\gh ! c5t] ( ! be>+1 /&>ds #c_/d in* above ! base4 ,! lev] is clamp$ to ! c5t] ( ! pivot by means ( a small ma*9e screw4 ,a heavy piece ( spr+ brass1 ,s1 #a_/b in* wide & #c in*es long1 is fa/5$ to ! base at "o end ) a %ort #h-cb screw4 ,! o!r end is b5t upw>d s t x presses h>d aga9/ ! l[] end ( an adju/+ screw1 :i* passes ?r\gh ! lev] #a #a_/d in*es =w>d ( ! pivot4 ,?is spr+ s]ves z an auxili>y conductor & saves ! key f c>ry+ an excessive curr5t ?r\gh its be>+s4 ,by adju/+ ! ?umbscrew1 ! t5sion ( ! key may be regulat$ to suit ! op]ator4 ,! contacts ( ! key are #a_/h-;in* r\nd nickel /eel alloy or pure silv]1 set 9 %ort #a_/d-;in* ma*9e screws :i* fit into correspond+ly ?read$ holes 9 ! base & ! lev]4 ,?is makes ! contacts easily removable = r5ewal4 ,! l[] contact is set 9 a long] screw ?an ! upp] "o s t connection may be made to x4 ,x is insulat$ f ! base by a h>d rubb] bru%+4 ,! contacts mu/ be directly above "o ano!r & 9 p]fect alignm5t or else !y w pit & /ick4 ,,*apt] ,,xi4 ,,a]ial ,,swit*es ,,& ,,an*or ,,gaps4 ,"s =m ( swit* = quickly connect+ ! a]ial & gr\nd to ei!r ! transmitt+ or receiv+ app>atus is necess>y4 ,l[ p[]$ /ations us+ an induction coil z a transmitt] w f9d a #bej-volt d\ble pole1 d\ble ?r[ porcela9 base swit* to be suitable4 ,su* a swit* is connect$ up accord+ to ! diagram %[n 9 ,fig4 #gj4 ,z cle>ly illu/rat$1 ! receiv+ app>atus is 9 use :5 ! swit* is ?r[n to ! "r1 & ! transmitt] is ready = op]ation :5 ! swit* is 9 ! left-h& position4 ,! ease & spe$ ) :i* su* a swit* may be ?r[n f "r to left or vice v]sa may be mu* facilitat$ by fitt+ x ) a l>g] & long] h&le ?an ! "o usually provid$4 ,illu/ration3 ,fig4 #gj4 ,connections = ,a]ial ,swit*4 ,an ord9>y d\ble pole1 d\ble ?r[ swit* %\ld be m\nt$ on ! wall )9 easy rea* ( ! op]ator1 :ile ! two types ( swit* ab\t to be describ$ are be/ situat$ directly on ! op]at+ table alongside ( ! transmitt+ key4 ,all insulat$ p>ts ( an a]ial swit* su* z ! base1 insulat+ b>1 h&le1 etc41 %\ld be made ( "s good insulat+ mat]ial1 z porcela91 h>d rubb] or ebonite4 ,all insulation :i* is us$ 9 p[] swit*es su* z slate1 wood1 m>ble1 etc41 is wor?less & %\ld n be us$4 ,if a loop a]ial sy/em is us$1 a swit* is necess>y1 :i* w break ! prim>y transmitt+ curr5t s t 9 case ( an accid5tal t\* ( ! key :ile receiv+1 ! high voltage dis*>ge w n pass across ! an*or gap into ! receptor & badly damage ! same or %ock ! op]ator4 ,! connections ( su* a swit* & ! loop a]ial are %[n 9 ! wir+ diagram ( ! ,de ,=e/ sy/em4 ,illu/ration3 ,fig4 #ga4 ,a]ial ,swit*es4 ,a swit* may be easily con/ruct$ f a #ej amp]e1 s+le ?r[1 triple pole1 fuseless p[] swit*4 ,if x is m\nt$ on a slate base remove x & set x up on a base ( ! same size made ( fib] or porcela94 ,flat unglaz$ tiles ( v>i\s sizes are obta9able f tile sett]s at a v l[ co/4 ,!y may be easily bor$ ) an ord9>y /eel twi/ drill4 ,su* tiles are excell5t insulators :5 n expos$ to moi/ure & are useful = bases1 etc41 9 _m cases4 ,a heavy coat ( %ellac v>ni% w make ! tile imp]vi\s to moi/ure4 ,a h>d rubb] rod1 ,s1 #c in*es long & #e_/h in* diamet]1 is m\nt$ on bo? sides ( ! base 9 alignm5t ) ! contacts4 ,a /rip ( h>d rubb]1 ,y1 #a in* wide1 #a_/b in* ?ick & #f #a_/b in*es long is fitt$ ) two contacts simil> to ^? m\nt$ on ! base ( ! swit*4 ,! contacts are m\nt$ at a di/ance ap>t equal to ! di/ance betwe5 ! outside knife blades ( ! swit*4 ,a #a_/h-;in* hole is bor$ ?r\gh ! /rip at bo? ends1 ?r\gh ! axis ( ! rods along _! entire l5g? & ?r\gh ! base4 ,a piece ( brass rod #d in*es long & ?read$ at bo? ends ) an #h-cb die is pass$ ?r\gh ! holes & yoke1 s t ! rods may be held firmly to ! base & ! /rip to ! tops ( ! rods by two nuts screw$ on ! ends ( ! brass rod4 ,illu/ration3 ,fig4 #gb4 ,detail ( ,contacts4 ,! upp] contacts %\ld be directly ov] ! two outside l[] ones4 ,!y are made f a /rip ( brass #a_/b in* wide1 #c #a_/b in*es long & #a_/af in* ?ick 7b5t z 9 ,fig4 #gb74 ,a b9d+ po/ is m\nt$ on ! yoke directly above & connect+ ) ea* "o ( ! contacts4 ,! middle pole ( ! swit* is connect$ to ! prim>y ( ! coil or trans=m]1 s t :5 ! swit* is d[n1 ! prim>y circuit is complet$1 & :5 x is up x is brok54 ,illu/ration3 ,fig4 #gc4 ,details ( ,swit* ,p>ts4 ,"s may pref] to make ! complete swit*1 & 9 t case ! dim5sions giv5 9 ,fig4 #gc may be ( aid4 ,! knife blades are #f in*es long1 #e_/h in* wide & #a_/h in* ?ick4 ,?ree are requir$4 ,a #a_/h-;in* hole is bor$ #c_/h in* f "o end1 & ! o!r end is cut out 9 ! %ape %[n 9 ! illu/ration4 ,an insulat+ b> #e x #c_/d x #e_/h in*es is made ( h>d rubb] & ?ree not*es are cut 9 ! back face1 "o directly 9 ! c5t] & "o #b in*es on ei!r side4 ,illu/ration3 ,fig4 #gd4 ,me?od ( ,fa/5+ ,knife4 ,?ree #a_/h-;in* holes are bor$ "o 9 ! c5t] ( ea* groove & at "r angles to x4 ,an #h-cb ma*9e screw #c_/d in* long is plac$ 9 ! not* 9 ! end ( ! knife blade & ! screw pass$ ?r\gh ! hole 9 ! insulat+ b>4 ,! blade may !n be clamp$ tightly 9 place by putt+ a nut on ! end ( ! screw4 ,! screw :i* holds ! middle knife blade 9 place is long] ?an ! o!r two s t a h&le may be fitt$ on4 ,! be>+s are made ! same size & %ape z ! contacts illu/rat$ 9 ,fig4 #gb1 ) ! exception t a #a_/h-;in* hole is bor$ ?r\gh ne> ! top s t a small bolt may be slipp$ 9 to hold ! knife blades 9 place4 ,! base ( ! swit* measures #h x #i x #c_/d in*es4 ,! p>ts are assembl$ z 9 ,fig4 #ga4 ,ano!r type ( a]ial swit* call$ a ,t swit* is illu/rat$ 9 ! same figure4 ,a piece ( #c_/d-;in* h>d rubb] is saw$ 9 ! %ape ( a ,t1 #c #a_/b in*es high & #f #a_/b in*es wide at ! top4 ,! upp] contacts are m\nt$ on arms ( ! ,t & connect$ to b9d+ po/s plac$ imm$iately above !m1 ,a slot1 #a_/b in* wide & #c in*es long1 saw$ 9 ! c5t] ( ! leg ( ! ,t1 p]mits ! middle knife blade to move )\t ob/ruction4 ,illu/ration3 ,fig4 #ge4 ,t ,a]ial ,swit*4 ,a d\ble pole1 d\ble ?r[ swit* may be easily adapt$ to =m a ,t swit*4 ,two knives are cut f %eet brass1 ( ! same %ape z ^? already on ! swit* b twice z long4 ,! contacts at "o end ( ! porcela9 base are remov$ & ! be>+s ( ! knife blade fa/5$ !re 9 _! /ead4 ,?is =ms a s+le ?r[1 d\ble pole swit* hav+ knife blades twice ! l5g? ( ! orig9al d\ble pole1 d\ble ?r[ swit*4 ,a ,t %ap$ support = ! upp] contacts may be saw$ out ( #a_/b-;in* h>d rubb] & smoo!d up ) a file4 ,! support is fa/5$ upright by means ( two screws :i* pass ?r\gh holes 9 ! c5t] ( ! base :]e ! knife be>+s orig9ally 74 ,! two contacts :i* 7 remov$ f ! base are fa/5$ to ! support directly ov] ! knife blades s t !y make a good contact :5 ! swit* is up4 ,two b9d+ po/s m\nt$ above ! contacts make connection ) !m4 ,if desirable ! swit* may be fitt$ ) a ?ird knife blade & contact s t :5 ! swit* is up 9 position = receiv+1 ! prim>y circuit ( ! induction coil or small trans=m] is op54 ,x is obvi\s t ! dim5sions1 etc41 ne$ n be ! same z ^? giv5 "h b may be adapt$ to suit ! size & design ( ! swit* :i* is to be alt]$4 ,! knives %\ld always be z long z conv5i5t & ! contacts sep>at$ by a wide space4 ,illu/ration3 ,fig4 #gf4 ,unit$ ,wireless ,lightn+ ,swit*4 ,illu/ration3 ,fig4 #gg4 ,%oemak] ,tun+ ,coil & ,a]ial ,swit*4 ,figs4 #gf & #gg illu/rate ! a]ial swit*es us$ 9 ! in/allations ( ! ,unit$ ,wireless ,telegraph ,company4 ,^! illu/rations give a good idea ( ! long knife blades employ$4 ,! lightn+ swit* is fitt$ ) a micromet] sp>k gap on top ( ! swit* :i* is 9 s]vice :5 ! h&le is up4 ,! small sp>k gap af=ds a pa? = ! lightn+ to jump into ! gr\nd1 b _c be bridg$ by ! receiv+ curr5ts4 99,an*or ,gaps499--,:5 a loop a]ial sy/em is employ$ = bo? transmitt+ & receiv+1 a device kn[n z an an*or gap becomes necess>y4 ,illu/ration3 ,fig4 #gh4 ,unit$ ,wireless ,an*or ,gaps4 ,! con/ruction & connection ( a simple an*or gap are %[n 9 ,fig4 #gi4 ,a r+ #a #c_/d in*es outside & #a #a_/d in*es inside is cut out ( #e_/h-;in* h>d rubb] or fib] & smoo!d up4 ,?ree #a_/h-;in* holes are bor$ 9 ! p]iph]y ( ! r+ at #abj degrees to ea* o!r4 ,! holes are ?read$ ) a #aj-bd tap4 ,?ree small b9d+ po/s are ea* fitt$ ) a #c_/af-;in* brass rod #g_/h in* long1 hav+ a #aj-bd ?read s t !y may be screw$ into ! holes 9 ! r+4 ,illu/ration3 ,fig4 #gi4 ,an*or ,gap4 ,! gap betwe5 ! ends ( ! two rods connect$ to ! a]ial & ! receiv+ app>atus is adju/$ until x is ab\t #a_/h in* long4 ,! ?ird po9t is screw$ 9 until x all b t\*es ! o!r two4 ,,*apt] ,,xii4 ,,hot ,,wire ,,ammet]4 ,:5 a curr5t passes ?r\gh a conductor1 x g5]ates heat 9 proportion to ! resi/ance (f]$ & ! am\nt ( curr5t fl[+4 ,heat causes metals to exp& suffici5tly s t ^! two prop]ties may be appli$ to ! con/ruction ( a hot wire ammet] = ! measurem5t ( alt]nat+ curr5ts ( high frequ5cy & pot5tial4 ,! hot wire ammet] is plac$ 9 s]ies ) ! a]ial1 s t by not+ ! deflection ( ! po9t]1 ! inductance1 capacity & sp>k gap may be adju/$ until ! met] gives a maximum read+4 ,illu/ration3 ,fig4 #hj4 ,simple ,hot ,wire ,met]4 ,a simple & crude =m ( met] :i* is suffici5tly s5sitive = mo/ exp]im5tal "w is illu/rat$ 9 ,fig4 #hj4 ,a piece ( ,no4 #cf ,b4 ,s4 plat9um wire is seal$ 9 ! bulb ( an ord9>y air !rmomet]4 ,:5 ! wire becomes heat$ by a pass+ curr5t ( electricity1 x causes ! air 9 ! bulb to exp& & *ange ! height ( ! color$ liquid 9 ! tube4 ,an air-!rmomet] is simply a glass tube ( f9e bore hav+ a bulb bl[n at ! upp] end & ! free end imm]s$ 9 a res]voir ( ink or "s o!r color$ liquid4 ,! in/rum5t is put 9 work+ ord] by grasp+ ! bulb 9 ! palm ( ! h&1 s t ! w>m? ( ! h& w exp& ! air & cause "s ( x to escape f ! l[] end ( ! tube4 ,^u remov+ ! h&1 ! air w contract & suck "s ( ! liquid up into ! tube4 ,x %\ld rise only ab\t half way to ! bulb1 & ! tube %\ld be ab\t #ah in*es long s z to leave room = *anges 9 ! position ( ! column due to v>iations 9 ! outside atmosph]e4 ,a c>dbo>d scale graduat$ 9 in*es & read+ d[nw>d is fa/5$ 9 back ( ! tube4 ,! tube %\ld h a f9e bore s z to make ! in/rum5t z s5sitive z possible4 ,! be/ liquid to use is alcohol1 color$ ) a little anil9e dye4 ,alcohol has a l[] specific gravity ?an wat]1 & ! column w be m s5sitive to small *anges ( pressure4 ,! same figure %[s a =m ( met] devis$ & us$ ) success by ! au?or4 ,two tubes are fitt$ to ! bulb1 a l>ge "o hav+ a bore ( ab\t #j4a ( an in* & ano!r ab\t #j4jd in*4 ,connection is e/abli%$ by ! aid ( two corks & a %ort l5g? ( glass tub+ "o in* 9 diamet]4 ,! tubes are b5t ,u %ap$1 & a little color$ alcohol is plac$ 9 ea*1 s t ! bottle res]voir is unnecess>y4 ,! tube ( l>ge bore is fitt$ at ! top ) an ord9>y glass /opcock su* z t us$ 9 *emical laboratories4 ,! /opcock is left op5 & ! transmitt] is set 9 op]ation by hold+ d[n ! key4 ,! helix1 etc41 are adju/$ until ! l>g] tube %[s a maximum read+4 ,! /op-cock is !n clos$ & ! in/rum5ts fur!r adju/$ by not+ ! read+ 9 ! f9] tube :i* corresponds to mu* small] *anges 9 curr5t4 ,! f9] bore _c at fir/ be us$ alone because ! l>ge *anges ( curr5t w\ld bl[ ! liquid out ( ! tube4 ,9 lieu ( a glass /opcock1 a piece ( rubb] tub+ may be plac$ ov] ! end ( ! tube & clos$1 :5 necess>y1 ) a p9* cock4 ,illu/ration3 ,fig4 #ha4 ,met] ) ,case ,remov$4 ,fig4 #ha %[s a m elaborate & s5sitive =m ( met] :i* is n only suitable = exp]im5tal outfits b may be us$ ) good results = m c>eful "w4 ,! advantage ( ! =m ( met] "h describ$ is t x is pivotless s to speak1 & conta9s no be>+s :i* require jewels to elim9ate friction4 ,! hot wire is plat9um1 & 9 ord] to comp5sate = ext]nal *anges ( ! atmosph]ic temp]ature1 is m\nt$ on a /rip ( glass4 ,glass & plat9um exp& at ne>ly ! same rate1 & ! wire is ?us kept taut & prev5t$ f *ang+ ! position ( ! po9t] except :5 ! curr5t passes4 ,illu/ration3 ,fig4 #hb4 ,glass ,comp5sat+ ,/rip4 ,drill f\r #a_/h-;in* holes 9 a piece ( w9d[ glass #f in*es long & #a in* wide4 ,! location ( ! holes is %[n 9 ,fig4 #hb4 ,! two at ! ends s]ve to m\nt ! /&>ds1 ,a & ,b1 & ^? at ! c5t] to fa/5 d[n ! /rip to ! base4 ,! holes are drill$ ) a small ?ree-corn]$ file :i* has be5 brok5 (f & set 9 a brea/ drill4 ,! brok5 end %\ld be us$ to drill ! glass & be kept ?or\ghly lubricat$ ) camphor & turp5t9e4 ,) a little c>e & pati5ce ! holes may be drill$ )\t break+ ! glass4 ,illu/ration3 ,fig4 #hc4 ,details ( ,hot ,wire ,supports4 ,two brass /&>ds are fa/5$ on ea* end ( ! glass4 ,!y are b5t out ( %eet brass & are #c_/d in* high & #c_/h in* wide4 ,a brass spr+ ( ! same wid? & #a #a_/d in*es long is clamp$ "u "o /&>d4 ,! /&>d :i* holds ! spr+ 9 position is tapp$ = a small ?umbscrew :i* may be secur$ f a b9d+ po/4 ,sold] a small brass p9 to ! top ( ! spr+ & ano!r "o to ! top ( ! /&>d :i* is fa/5$ at ! opposite end ( ! glass /rip4 ,"s pap] or rubb] wa%]s mu/ be plac$ betwe5 ! feet ( ! /&>ds & ! glass /rip to prev5t x f crack+ :5 ! screws are tight5$4 ,= a /ation up to "o-half ,k4,w4 9 p[] ! hot wire mu/ be ,no4 #dj ,b4 ,s4 gauge plat9um4 ,= l>g] /ations a s+le ,no4 #cf wire may be us$ or ?ree ,no4 #dj wires 9 p>allel4 ,! wire mu/ be ab\t #g in*es long4 ,/ret* x betwe5 ! /&>d1 ,a1 & ! spr+1 ,c4 ,wrap ! ends ar\nd ! p9s & sold] !m !re1 us+ z small am\nt ( sold] z possible4 ,! t5sion ( ! wire1 :i* %\ld be taut1 is adju/$ ) ! ?umbscrew4 ,take a piece ( ! plat9um wire ab\t #a_/b in* long & make a little eyelet at "o end4 ,wrap ! /raight end ar\nd ! c5t] ( ! long hot wire & tie a piece ( silk 9 ! eyelet4 ,illu/ration3 ,fig4 #hd4 ,details ( ,movem5t4 ,! glass /rip & its /&>ds support+ ! hot wire may !n be fa/5$ to ! basebo>d ( ! in/rum5t by means ( two r\nd head$ brass wood screws4 ,two rubb] wa%]s mu/ be int]pos$ betwe5 ! glass & ! wood4 ,a piece ( #c_/cb in* brass #a_/b in* wide & #c #a_/d in*es long is b5t 9 ! %ape %[n by ,f 9 ,fig4 #hd4 ,! upp] end is bor$ & tapp$ to receive a ?umbscrew simil> to ! "o 9 ! /&>d on ! glass /rip4 ,two brass spr+s #a_/fd in* ?ick1 #c_/h in* wide & #a #a_/d in*es long are sold]$ or rivet$ at opposite ends ( ,f 9 ! positions %[n 9 ,fig4 #he4 ,! spr+s %\ld project "o in* f ! upright4 ,a small hook made f an ord9>y p9 is sold]$ to ! outside end ( ea*4 ,illu/ration3 ,fig4 #he4 ,complete ,movem5t4 ,! movem5t is %[n 9 p]spective by ,fig4 #he4 ,g is a rectangle ( v ?9 copp]1 #a_/b in* long & #a_/d in* wide1 hav+ a little projection #a_/d in* long b5t 9 a curve s t x =ms a sextant ( a circle1 ( :i* ! int]section ( ! diagonals ( ,g w\ld be ! c5t]4 ,! po9t] is a piece ( /eel wire #e in*es long4 ,x is slightly flatt5$ by hamm]+ s t x w reta9 its %ape & n curl4 ,ab\t #a_/b in* is all[$ to project ?r\gh ,g & is weight$ ) a lead %ot s z to p>tly c\nt]balance its weight4 ,two loops ( wire are fa/5$ to ! corn]s ( ,g by ty+ !m 9 holes :i* are bor$ !re = t purpose4 ,! wire is f9e phosphor bronze 4#jjc-4jje ( an in* 9 diamet]1 :i* is us$ = susp5d+ ! movem5ts ( delicate galvanomet]s4 ,pass ! loops ov] ! hooks on ! spr+s & adju/ until ! po9t] moves horizontally4 ,!n fa/5 ! wires p]man5tly to ! hooks by means ( a small drop ( sold]4 ,illu/ration3 ,fig4 #hf4 ,side ,view ( ,hot ,wire & ,movem5t4 ,! movem5t is m\nt$ 9 ! position %[n by ,fig4 #hf4 ,! silk ?read ti$ to ! eyelet runs to ! little sextant & is cem5t$ at ! fur!r end by means ( a small drop ( seal+ wax4 ,! scale is a piece ( %eet copp] or brass1 cov]$ ) :ite pap] & calibrat$ 9 degrees or made to read 9 amp]es by connect+ x 9 s]ies ) an ammet] & a s\rce ( direct curr5t4 ,a rheo/at %\ld be includ$ 9 ! circuit & ! curr5t v>i$ s t v>i\s values may be m>k$ (f4 ,all ! diff]5t po9ts mu/ be locat$ by s5d+ an actual curr5t ( t value ?r\gh ! met]4 ,an error is liable to result if any ( ! po9ts are m>k$ by guesswork1 = ! divisions gr[ small] & small] z !y become f>!r away f z]o4 ,= example a position ( ! po9t] correspond+ to #j4a ( an amp]e w n be half way betwe5 z]o & #j4b b w be ne>] ! #j4b division4 ,! resi/ance ( wires to high frequ5cy curr5ts is mu* high] ?an _! resi/ance to con/ant curr5ts4 ,?is w\ld seem at fir/ to indicate t our met] w give a high] read+ = an equal curr5t value1 :5 us$ ) a high frequ5cy curr5t aft] be+ calibrat$ ) a direct curr5t4 ,b ) wires ( v small diamet] su* z ,no4 #dj ,b4 ,s4 gauge !re is almo/ no p]ceptible diff]5ce & consequ5tly no error unless ! frequ5cy ( ! oscillations exce$s #a1jjj1jjj p] second1 :i* is v unlikely ) ! sp>k me?od ( wireless telegraphy4 ,fig4 #hg illu/rates ! =m ( hot wire ammet] us$ by ! ,unit$ ,wireless ,telegraph ,co4 = tun+ _! in/allations4 ,illu/ration3 ,fig4 #hg4 ,unit$ ,wireless ,hot ,wire ,ammet]4 ,! pivotless met] j describ$ %\ld be fitt$ ) heavy b9d+ po/s :i* are connect$ to ! brass /&>ds m\nt$ on ! glass /rip by means ( /r&$ copp] wire4 ,! met] %\ld be fitt$ ) a case & glass cov] to exclude du/ & prev5t injury to ! work+ p>ts4 ,x %\ld be m\nt$ 9 su* a position t ! weight ( ! po9t] is suffici5t to keep ! silk ?read taut s t :5 ! wire exp&s ! po9t] :i* is normally at z]o w fall ( its own weight4 ,:5 ! wire cools aft] ! curr5t has ceas$ to fl[1 x w contract & draw ! po9t] up aga94 ,plat9um wire w give good results1 b = m accurate "w an alloy kn[n z plat9oid is mo/ suitable4 ,detail$ in/ructions = tun+ ! transmitt+ circuits by means ( a hot wire ammet] are giv5 9 ! *apt] on ,transmitt+ ,helixes4 ,,*apt] ,,xiii4 ,,oscillation ,,detectors4 ,,univ]sal ,,detector4 ,! purpose & position ( ! detector 9 a wireless telegraph sy/em has already receiv$ "s notice 9 ! fir/ *apt]1 b its op]ation & adju/m5t are s important t ?is *apt] des]ves ! mo/ c>eful consid]ation4 ,! receiv+ range ( a /ation is n z mu* dep5d5t ^u ! a]ial sy/em z x is ^u ! adju/m5t ( ! tun+ circuits & ! detector itself4 ,x is sugge/$ t ! amateur exp]im5t] n conf9e 8 "w to receiv+ only ) a s+le type ( detector b r accu/om himself to ! diff]5t in/rum5ts4 ,dur+ ! pa/ few ye>s _m wireless telegraph detectors h be5 inv5t$ :i* l5d !mselves readily to amateur con/ruction4 ,x is some:at ( a conv5i5ce to h a univ]sal detector :i* ) a little manipulation may be us$ z m ?an "o type & ?us save unnecess>y exp5se & mu* labor4 ,! univ]sal detector %[n 9 ,fig4 #hh has be5 s design$ z to pres5t a good appe>ance & at ! same "t be successfully op]at$ z an electrolytic1 tantalum1 p]oxide ( lead1 silicon1 c>borundum or any ( ! cry/al type detectors4 ,illu/ration3 ,fig4 #hh4 ,univ]sal ,detector4 ,illu/ration3 ,fig4 #hi4 ,details ( ,univ]sal ,detector4 ,! /&>d1 ,r1 is a #c_/d-;in* h>d rubb] rod1 #a #a_/d in*es long1 ) a #c_/af in* hole bor$ ?r\gh its axis4 ,a spr+1 ,s1 is made aft] ! plan %[n 9 ,fig4 #hf4 ,x is #b in*es long & #a_/af in* ?ick4 ,a brass coll> #a_/h in* ?ick & #c_/h in* diamet] is sold]$ on ! small] end ( ! spr+ 9 ord] to s re5=ce x t x may be bor$ & ?read$ ) an #h-cb tap to receive a ?umbscrew4 ,! brass /&>d1 ,d1 is a small cyl9d] #c_/h in* high & #a_/b in* 9 diamet]4 ,a #c_/af in* hole is bor$ ?r\gh its axis4 ,! arm1 ,a1 is brass & measures #a #a_/b x #a_/b x #a_/d in*es4 ,! ends are r\nd$ by fil+ or gr9d+ s t !y co9cide ) ! semi-circumf]5ce ( a circle hav+ a diamet] ( #a_/b in*4 ,two holes are bor$ on ! c5t] l9e #a_/d in* f ea* end4 ,"o is a #a_/h-;in* hole & ! o!r is ?read$ ) a #aj-cb tap to fit ! l>ge adju/+ screw4 ,! adju/+ screw1 ,h1 is #a #a_/d in*es long & has a #aj-cb ?read4 ,a h>d rubb] head #a in* ?ick & #a #a_/d in*es 9 diamet] is clamp$ to ! upp] end by means ( two hexagonal brass nuts4 ,a small brass wa%] %\ld be plac$ betwe5 ! head & ea* ( ! nuts to give x a m f9i%$ appe>ance & prev5t ! nuts f m>r+ ! rubb]4 ,illu/ration3 ,fig4 #ij4 ,p>ts ( ,univ]sal ,detector4 ,! brass b$ plate1 ,b1 is #a_/h in* ?ick1 #c in*es long & #b in*es wide4 ,two holes are drill$ on ! c5t] l9e #i_/af in* & #g_/h in* f ei!r end4 ,"o is #c_/h in* 9 diamet] & ! o!r is ?read$ ) an #h-cb tap4 ,an insulat+ bu%+ 9 ! %ape ( a h>d rubb] wa%] on ! l[] end ( ,r1 #a_/h in* ?ick & #c_/h in* 9 diamet]1 has a #c_/af-;in* hole bor$ 9 its c5t] & is fitt$ 9 ! l>g] hole 9 ! b$plate4 ,! :ole detector is assembl$ & m\nt$ on a h>d rubb] base #d x #e x #d in*es4 ,a brass b9d+ rod1 ,m1 #c #a_/d in*es long & hav+ an #h-cb ?read1 is pass$ successively ?r\gh ! arm1 ! brass /&>d1 ! spr+1 ! h>d rubb] /&>d & ! b$plate4 ,a hexagonal brass nut on ! "u side ( ! base & a ?umb nut on ! brass arm s]ves to b9d ! :ole tightly toge!r4 ,f\r b9d+ po/s are m\nt$ on ! f\r corn]s ( ! base4 ,two are connect$ to ! brass b9d+ rod & two to ! b$plate4 ,?is completes ! univ]sal "p ( ! detector4 ,! rema9+ p>ts are ea* describ$ "u ! head+s ( ! respective detectors to :i* !y belong4 ,,electrolytic ,,detectors4 99,b>e ,po9t ,type499--,al?\gh ! electrolytic is ! olde/ ( a long l9e ( v s5sitive detectors1 x /ill holds fir/ rank :5 9 ! h&s ( an exp]i5c$ & skillful op]ator4 ,x exi/s 9 two diff]5t =ms1 b ! m favor$ is t kn[n z ! ,fess5d5 b>e po9t type1 :i* consi/s ( a v f9e ,woola/on plat9um wire 74#jja-4jjjjb ( an in* 9 diamet]7 dipp+ 9 a small cup ( dilute acid4 ,! acid is ei!r #bj p] c5t *emically pure nitric or sulphuric4 ,illu/ration3 ,fig4 #ia4 ,b>e ,po9t ,electrolytic ,detector4 ,a l>ge electrode ( plat9um wire or foil dips into or is seal$ 9 ! bottom ( ! cup s z to make an electrical connection ) ! liquid4 ,! f9e ,woola/on wire is clamp$ ov] ! cup 9 a hold] :i* p]mits ( v]tical adju/m5t1 by means ( a ?umbscrew1 s t ! dep? ( imm]sion 9 ! acid may be regulat$4 ,illu/ration3 ,fig4 #ib4 ,effect ( ,expos+ too mu* ,wire4 ,woola/on wire is cov]$ ) a comp>atively ?ick coat+ ( silv]1 :i* be=e us+ mu/ be remov$ f ! end = ab\t #a_/cb in* by dipp+ x 9 /rong nitric acid1 :i* w dissolve ! silv] & expose ! almo/ invisible plat9um core4 ,too mu* ( ! f9e plat9um core mu/ n be expos$ or else ! surface t5sion ( ! acid w cause ! wire to curl ov] & pres5t a l>ge flat surface in/ead ( a f9e po9t4 ,?is is a v necess>y & important precaution1 = ! detector is m s5sitive z ! area ( contact betwe5 ! f9e wire & ! liquid is small]4 ,:5ev] ?is condition is rea*$ ! end ( ! wire %\ld be cut (f ) a pair ( %>p scissors & a new po9t expos$4 ,illu/ration3 ,fig4 #ic4 ,electrolytic ,detector ,circuits4 ,! detector circuit is %[n 9 ,fig4 #ic4 ,! f9e b>e po9t is always made ! positive or anode ( ! batt]y circuit4 ,o!rwise ! detector w n op]ate4 ,a pot5tiomet] mu/ be %unt$ across ! t]m9als ( ! batt]y to r$uce ! voltage to a value j bel[ t :i* is requir$ to break d[n ! ?9 film ( oxyg5 gas :i* collects on ! b>e po9t & pol>izes x or insulates x f ! liquid s t little or no batt]y curr5t c fl[4 ,?is film ( gas is caus$ by ! electrolysis ( ! acid solution & ! decomposition ( ! wat] into hydrog5 & oxyg5 gas4 ,:5 oscillations are set up 9 ! receiv+ a]ial & !y surge ?r\gh ! detector1 a suffici5t e4m4f4 is g5]at$ to break d[n ! film ( gas & p]mit ! batt]y curr5t to fl[ aga94 ,! passage ( curr5t causes ! signals 9 ! telephone receiv]s4 ,! electrolytic cup = ! univ]sal detector is illu/rat$ 9 ,fig4 #ij4 ,x is made ( a piece ( h>d rubb] rod #c_/d in* 9 diamet] & #c_/d in* high4 ,a recess #a_/b in* 9 diamet] & #c_/h in* deep is cut 9 ! top to conta9 ! acid4 ,a small hole #a_/d in* deep is bor$ 9 ! "u side & ?read$ ) an #h-cb tap4 ,a brass p9 #a_/b in* long1 hav+ a correspond+ ?read1 is fitt$ 9 ! hole4 ,! p9 may !n be screw$ into ! small hole 9 ! b$plate4 ,a piece ( ,no4 #cj ,b4 ,s4 gauge plat9um wire or a /rip ( plat9um foil is clamp$ betwe5 ! bottom ( ! cup & ! b$plate & !n b5t ov] ! top ( ! cup into ! liquid4 ,illu/ration3 ,fig4 #id4 ,electrolytic ,detector4 ,a #a_/af-;in* hole #a_/d in* deep is bor$ 9 ! l[] end ( a ?umbscrew hav+ an #h-cb ?read4 ,a piece ( ,woola/on wire #a_/b in* long is plac$ 9 ! c5t] ( ! hole & t9foil pack$ into ! surr\nd+ space ) ! head ( a sew+ ne$le until ! wire is held firmly 9 position4 ,! free end ( ! wire mu/ !n be dipp$ 9 "s /rong nitric acid to remove ! silv]4 ,! ?umbscrew is plac$ 9 ! coll> on ! end ( ! spr+ ( ! univ]sal detector & l[]$ until ! b>e po9t almo/ t\*es ! surface ( ! electrolyte 9 ! cup b5ea?4 ,pressure mu/ !n be appli$ to ! spr+ by turn+ ! l>ge adju/+ screw until ! b>e po9t t\*es ! liquid & a click is he>d 9 ! telephone receiv]s & a fa9t bubbl+ s\nd is also audible4 ,! adju/+ screw mu/ !n be sl[ly & c>efully turn$ 9 ! opposite direction s z to raise ! po9t until ! bubbl+ *anges to a hiss+ s\nd4 ,! po9t is !n above ! level ( ! electrolyte 9 ! cup b is /ill 9 contact ) x because ( ! capill>y action ( ! f9e wire & ! liquid4 ,by us+ ! l>ge adju/+ screw z mu* z possible1 in/ead ( ! small ?umbscrew1 ! po9t is rais$ or l[]$ )\t giv+ x a circul> motion & mu* f9] adju/m5t is made possible4 ,! pot5tiomet] is adju/$ until ! hiss+ noise caus$ by excessive batt]y voltage j disappe>s4 ,! detector is !n 9 its mo/ s5sitive condition = receiv+ signals4 ,:5 ! detector is 9 use = long p]iods1 ! pot5tiomet] mu/ be frequ5tly readju/$ to comp5sate ! gradual loss 9 voltage ( ! batt]y4 ,x is well to provide a small swit* :i* w disconnect ! batt]y f ! pot5tiomet] :5 ! detector is n 9 use4 ,9 ! same case ! acid %\ld be remov$ & plac$ 9 a tightly /opp]$ bottle4 ,a pipette or f\nta9 p5 fill] furni%es ! mo/ conv5i5t means = fill+ or empty+ ! cup4 ,! acid mu/ be kept p]fectly pure & out ( contact ) all metals o!r ?an plat9um4 ,great c>e %\ld be ex]cis$ 9 fill+ ! cup1 = ! acid1 if spill$1 w n only badly corrode ! metal fitt+s1 b w also provide a curr5t leak & s]i\sly weak5 ! signals4 99,%oemak] & ,/one ,detectors499--,^! two types ( detectors make use ( glass po9ts1 s call$ because ! f9e plat9um wire is seal$ 9 a glass tube & ! end ( ! tube is !n gr\nd d[n on a f9e oil/one until ! plat9um wire is expos$4 ,?is results 9 a v f9e contact area & insures con/ant imm]sion ( ! po9t )\t readju/m5t4 ,illu/ration3 ,fig4 #ie4 ,=m+ ,glass ,po9t4 ,! f9e plat9um wire = a glass po9t may be secur$ f "o ( ! flam+ pocket cig> light]s mak+ use ( spongy plat9um4 ,! c5t] ( a ?ick wall$ glass tube is s(t5$ by heat & contract$ z %[n at ,a-,b 9 ,fig4 #ie4 ,aft] cool+1 ! tube is cut 9 half at ! po9t indicat$ by ! dott$ l9e4 ,! plat9um wire is plac$ 9 ! contract$ end ( ! tube & c>efully fus$ 9 s t ab\t "o-half ( ! wire1 :i* is ab\t #a_/b in* long1 is emb$d$ 9 ! glass4 ,! contract$ end ( ! tube conta9+ ! wire %\ld be clos$4 ,connection is e/abli%$ to ! upp] end ( ! f9e plat9um wire by fill+ ! tube ) m]cury & dipp+ a piece ( flexible conductor 9 ! m]cury4 ,! upp] end ( ! tube is clos$ & ! m]cury prev5t$ f escap+ by a small dab ( seal+ wax4 ,! po9t is sl[ly & c>efully rubb$ on a f9e oil/one kept well wet ) wat]4 ,! tube mu/ be held 9 a v]tical position s t ! glass w be gr\nd away at "r angles4 ,:5 x is ?\ght t ! plat9um wire has be5 expos$ by ! gr9d+1 connect ! flexible conductor to "o pole ( a batt]y4 ,! o!r pole ( ! batt]y is connect$ to a pair ( s5sitive telephone receiv]s & ! telephone receiv]s to a vessel conta9+ dilute acid4 ,if ! plat9um wire is expos$1 a %>p click w be he>d 9 ! telephone receiv]s :5 ! po9t is dipp$ 9 ! acid4 ,d n confuse ! %>p click ) ! s\nd :i* may be occasion$ because ! outside ( ! glass tube is damp or wet4 ,aft] ! po9t has be5 suffici5tly gr\nd1 disconnect ! te/+ app>atus & connect ! free end ( ! flexible conductor to a b9d+ po/ plac$ on ! end ( ! detector spr+1 ,s4 ,! detector circuit is simil> to t ( ! b>e po9t type4 ,illu/ration3 ,fig4 #if4 ,%oemak] ,detector4 ,! illu/ration %[s :at is sometimes call$ a prim>y cell detector because x furni%es its own curr5t & does n require a batt]y4 ,a ,/one detector may be v easily *ang$ to "o ( ! ,%oemak] type by sub/itut+ an amalgamat$ z9c rod = ! plat9um wire anode :i* makes connection ) ! liquid 9 ! cup4 ,?is comb9ation ( plat9um & z9c results 9 an electromotive =ce ( ab\t #j4g volt1 & ! telephone receiv]s are connect$ directly to ! t]m9als ( ! detector )\t any local batt]y or pot5tiomet]4 ,! electrolyte 9 ! cup mu/ be a #bj p] c5t solution ( pure sulphuric acid1 z nitric acid w\ld dissolve ! z9c 9 a v few m9utes4 ,! z9c mu/ be kept well amalgamat$ ) m]cury4 ,illu/ration3 ,fig4 #ig4 ,%oemak] ,detector ,circuits4 ,! ,%oemak] sy/em makes use ( a loop a]ial1 & ! circuits ) a s+le & d\ble coil tun] are illu/rat$ 9 ,fig4 #ig4 ,x is n necess>y to use ^!1 & ! detector w op]ate j exactly z well on a /raightaway a]ial4 99,lamp ,detector499--,all electrolytic detectors1 m especially ^? ( ! glass po9t type1 are subject to ! annoyance ( burn-outs4 ,t is1 ! f9e plat9um wire melts :5 receiv+ /rong signals f a ne>-by /ation4 ,9 su* case1 ! b>e po9t mu/ be l[]$ until x aga9 makes contact ) ! liquid1 & ! glass po9t regr\nd until ! wire is aga9 expos$4 ,:5 ?is tr\ble comes (t5 x is v conv5i5t to h at h& a simple detector :i* w n burn out & :i* may be sub/itut$ = ! usual "o :5 great s5sitiv5ess is n requir$4 ,illu/ration3 ,fig4 #ih4 ,lamp ,detector4 ,su* an in/rum5t is made by snipp+ (f ! tip ( a small inc&esc5t electric lamp & remov+ ! filam5t ) a wire4 ,"o ( ! lead+-9 wires is brok5 (f z close z possible to ! glass /ub & ! globe half fill$ ) a #bj p] c5t acid solution4 ,! brok5 wire mu/ be made ! negative or ca?ode & connect$ l a ,fess5d5 or ,/one detector4 ,?is lamp detector ?\gh crude w give good s]vice )\t burn+ out :5 us$ to receive f ne>-by /ations4 ,9 place ( a lamp detector1 a glass po9t hav+ a l>g] wire ?an t ( ! cig> light] may be us$ in/ead ( ! usual po9t1 b x w n be s s5sitive4 ,fig4 #ii illu/rates a simple =m ( electrolytic detector :i* is n s s5sitive z t %[n 9 ,fig4 #ajj b is /ill v s]viceable4 ,! cup is made f ! c>bon ( an old dry cell1 ! brass connect+ cap s]v+ v well to make ! connections to4 ,x has a recess ab\t #a_/b in* 9 diamet] & #a_/d in* deep cut 9 ! top to conta9 ! electrolyte4 ,! cup %\ld be ab\t "o in* high4 ,a file w smoo? up any r\gh edges & give x a good appe>ance4 ,illu/ration3 ,fig4 #ii4 ,simple ,electrolytic ,detector4 ,! yoke is made ( a piece ( #a_/h-;in* %eet brass ab\t #c_/d in* wide1 b5t 9 ! %ape %[n 9 ! illu/ration4 ,two small holes are drill$ 9 ! feet1 to s]ve to fa/5 ! yoke firmly to ! base & also to make connection to4 ,! adju/+ screw may be made f ! screw tak5 f ! c>bon ( an old dry cell4 ,to p]mit ( accurate adju/m5t1 x %\ld be fitt$ ) a l>ge head made f a piece ( #a_/d-;in* h>d rubb] or fib] cut 9 a circle ab\t #a #a_/d in*es 9 diamet]4 ,bore a small hole ab\t #a_/h in* 9 diamet] ?r\gh ! c5t] ( ! head & =ce x on ! screw4 ,a nut screw$ on ! "u side w !n clamp x tightly aga9/ ! brass head4 ,a hole is bor$ 9 ! c5t] ( ! yoke & a batt]y nut :i* w fit ! adju/+ screw sold]$ directly "u x4 ,! plat9um wire may be ei!r sold]$ to ! adju/+ screw or fa/5$ ) t9foil 9 ! me?od :i* has be5 describ$4 ,! cup & yoke are be/ m\nt$ on a piece ( h>d rubb] #a_/b in* ?ick1 #c in*es wide & #d in*es long4 ,a b9d+ po/ is plac$ ne> ea* ( ! f\r corn]s4 ,x is possible to d extremely f9e & long di/ance "w ) ! detector illu/rat$ 9 ,fig4 #ajj4 ,x is s arrang$ t ! b>e po9t ne$ n necess>ily be revolv$ :5 mak+ an adju/m5t1 & s x is possible to place x 9 a v s5sitive condition4 ,a brass /&>d1 ,u1 #a #a_/d in*es long is cut f a piece ( #a_/b-;in* rod4 ,a hole bor$ 9 ! top & bottom ( ! /&>d is ?read$ ) an #h-cb tap4 ,a brass rod1 ,r1 #b in*es long is ?read$ ) an #h-cb die ?r\gh\t its entire l5g?4 ,"o end is screw$ 9 ! top ( ,u4 ,a piece ( brass tub+1 ,p1 #a #a_/d in*es long & hav+ an int]nal bore ( #a_/b in* is slipp$ ov] ,u4 ,a slot cut 9 ,p fits ov] a small p9 set 9 ,u & p]mits ,p to be slid up & d[n b n to turn ar\nd4 ,illu/ration3 ,fig4 #ajj4 ,electrolytic ,detector4 ,a head 9 ! =m ( a circul> brass wa%]1 ,e1 #a_/h in* ?ick1 #a_/b in* 9 diamet] & hav+ a #e_/cb-;in* hole bor$ 9 ! c5t] is sold]$ 9 ! top ( ! tube1 ,p4 ,a circul> piece ( h>d rubb]1 ,h1 #b in*es 9 diamet] & #a_/b in* ?ick is fitt$ ) a brass bu%+ hav+ a hole 9 ! c5t] ) an #h-cb ?read to screw on ! rod1 ,r4 ,a spiral spr+ is plac$ ar\nd ,r betwe5 ,u & ! head ,e4 ,a small brass wa%] %\ld be plac$ betwe5 ,h & ,e 9 ord] to elim9ate friction4 ,:5 ,h is turn$ 9 "o direction1 ! spr+ w cause ,p to rise1 & :5 turn$ 9 ! o!r direction x w be l[]$4 ,a brass arm1 ,a1 #a_/d x #a_/d x #a #a_/b in*es c>ries a small ?umbscrew1 r1 at "o end1 :ile ! o!r end is sold]$ to ,p z %[n 9 ,fig4 #if4 ,! ,woola/on wire is sold]$ to ,t4 ,illu/ration3 ,fig4 #aja4 ,details ( ,electrolytic ,detector4 ,a small c>bon cup #c_/d x #c_/d in* s]ves to hold ! electrolyte4 ,a #c_/h-;in* hole is bor$ #a_/d in* deep 9 ! bottom ( ! cup & p\r$ full ( melt$ lead4 ,! lead is !n bor$ & tapp$ to fit a ma*9e screw :i* fa/5s ! cup to ! base4 ,connection is made f a b9d+ po/ to ! ma*9e screw4 ,a second b9d+ po/ is connect$ to ! screw :i* fits into ! bottom ( ,u & holds x to ! base4 ,if desirable a circul> piece ( h>d wood1 ,f1 may be turn$ out & glu$ to ! base ar\nd ! cup 9 ord] to give x a m f9i%$ appe>ance4 ,! ?umbscrew1 ,t1 is us$ to l[] ! b>e po9t until x almo/ t\*es ! liquid1 & !n ! l>ge head1 ,h1 is br\ght into play to make ! f9] adju/m5t4 99,increas+ ! ,s5sitiv5ess ( an ,electrolytic ,detector499 ,! s5sitiv5ess ( an electrolytic detector may be increas$ 9 ?ree ways1 viz41 by connect+ two detectors 9 s]ies1 by w>m+ ! electrolyte & by agitat+ x4 ,! fir/ me?od is cle>ly app>5t4 ,! second is accompli%$ by plac+ ! detector ov] a s& ba? & g5tly w>m+ x4 ,x w !n %[ a m>k$ increase 9 ! /r5g? ( ! signals at a temp]ature ( ab\t #cj ,c4 ,?is increase w cont9ue to rise ) ! temp]ature until x rea*es a maximum at ab\t #fj ,c4 ,illu/ration3 ,fig4 #ajb4 ,increas+ ! ,s5sitiv5ess ( an ,electrolytic ,detector4 ,branly discov]$ t a f9e /ream ( gas pass$ ?r\gh ! electrolyte 9 ord] to agitate x increases ! /r5g? ( ! signals 9 ! phones4 ,he devis$ a detector provid$ ) two extra plat9um t]m9als seal$ 9 ! cup4 ,:5 connect$ 9 s]ies ) a batt]y & an adju/able resi/ance1 ^! t]m9als cause electrolysis ( ! wat]1 & a f9e /ream ( oxyg5 & hydrog5 gas fl[s ?r\gh ! acid electrolyte4 ,! /ream ( gas agitates ! liquid j suffici5tly s t :5 oscillations /rike ! detector !y augm5t ! break+ d[n ( ! film ( gas :i* collects on ! f9e plat9um po9t4 ,?is results 9 an increase 9 ! batt]y curr5t fl[+ ?r\gh ! telephone receiv]s ( f two to f\r times & a correspond+ increase 9 ! volume ( s\nd4 ,! adju/able resi/ance is us$ to regulate ! decomposition ( ! electrolyte & =mation ( gas1 = if ?is proce$s too rapidly an undesirable rumbl+ noise w be produc$ 9 ! telephone receiv]s4 ,,tantalum ,,detector4 ,! tantalum detector is especially suitable = ! amateur exp]im5t] because its *ange 9 resi/ance :5 /ruck by oscillations is s great t high resi/ance telephone receiv]s are n necess>y4 ,its normal resi/ance is ab\t #ajjj-bjjj ohms1 & ?is sometimes drops z l[ z #abe-ajj ohms :5 /ruck by oscillations ( ord9>y /r5g?4 ,x is n ne>ly s s5sitive z ! electrolytic or cry/al detectors1 b gives v mu* l\d] tones 9 ! telephone receiv]s :5 us$ = %ort di/ance "w4 ,illu/ration3 ,fig4 #ajc4 ,tantalum ,detector4 ,! detector is easily made by sub/itut+ a piece ( tantalum wire = ! ,woola/on wire ( an ord9>y electrolytic detector4 ,! dilute acid solution is remov$ f ! cup & replac$ by "s pure m]cury4 ,! connections rema9 ! same z = ! b>e po9t4 ,! pot5tiomet] is adju/$ until ! pot5tial ( ! batt]y is 9 ! neighborhood ( #j4b-j4d volt4 ,! tantalum wire may be easily secur$ by break+ ! globe ( a tantalum lamp & us+ a piece ( ! filam5t4 ,x is be/ to snip (f ! lamp tip be=e break+ ! globe4 ,?is precaution admits ! air & prev5ts an explosion :i* w\ld %att] ! glass & scatt] ! filam5t 9 fragm5ts4 ,if ! univ]sal detector is us$ ) a tantalum po9t1 turn ! small ?umbscrew until ! wire almo/ t\*es ! surface ( ! m]cury4 ,!n l[] x ) ! l>ge adju/+ screw until ! tantalum t\*es ! surface & a %>p click is he>d 9 ! telephone receiv]s4 ,adju/ ! pot5tiomet] until ! signals are ! l\de/4 ,,cry/al ,,detectors4 ,c]ta9 m9]als & cry/als1 pr9cipally memb]s ( ! c>bon & sulphur gr\ps1 possess ! peculi> prop]ty ( rectify+ electrical oscillations & conv]t+ !m into a pulsat+ direct curr5t4 ,^! cry/als conduct ! curr5t bett] 9 "o direction ?an 9 ! o!r4 ,9 ! case ( a curr5t hav+ a pot5tial ( t5 volts & appli$ to ! ends ( a c>borundum cry/al1 ! curr5t may be "o hundr$ times great] :5 fl[+ 9 "o direction ?an :5 fl[+ 9 ! o!r4 ,?is ratio decreases z ! voltage is rais$1 = ) #be volts x may be only ab\t =ty times great]4 ,! cry/als :5 prop]ly ins]t$ 9 ! a]ial circuit are enabl$ to rectify ! oscillations & produce s\nds 9 ! telephone receiv]s )\t ! aid ( a batt]y4 ,! foll[+ is a p>tial li/ ( ! m9]als & cry/als exhibit+ ^! prop]ties to a suffici5t ext5t t !y are ( value z oscillation detectors 9 wireless telegraphy4 ,9 ! case ( iron pyrites ! writ] has f\nd t a specim5 ( ?is m9]al conta9+ v little or no copp] z an impurity does n exhibit ^! prop]ties to an appreciable ext5t4 ,illu/ration3 ,fig4 #ajd4 ,unit$ ,wireless ,c>borundum ,detector 7horizontal type74 ,9 ord] to use ! univ]sal detector = m9]als1 a special contact simil> to t %[n 9 ,fig4 #ij mu/ be made4 ,! contact is bor$ & ?read$ on its "u side to fit a brass p9 #c_/d in* long & hav+ an #h-cb ?read4 ,! o!r end ( ! p9 screws into ! hole 9 ! b$plate4 ,! l>ge knurl$ portion ( ! contact p]mits x to be rais$ or l[]$ )\t ! f+]s com+ 9 contact ) ! cry/al4 ,! cry/al is clamp$ betwe5 ! contact & ! spr+1 ,s4 ,! position is v>i$ until a s5sitive spot is f\nd & !n ! pressure is c>efully regulat$ by means ( ! l>ge adju/+ screw until ! signals 9 ! telephone receiv]s are ! l\de/4 ,if possible avoid t\*+ ! cry/als ) ! f+]s1 z ! oil & dirt1 ev5 ?\gh x _c always be se51 spoils _! value = long di/ance "w4 ,use in/ead a pair ( /eel =ceps4 ,illu/ration3 ,fig4 #aje4 ,unit$ ,wireless ,c>borundum ,detector 7v]tical type74 ,! ,unit$ ,wireless ,telegraph ,co4 makes use ( c>borundum 9 ! detectors %[n 9 ,figs4 #ajd & #aje4 ,! pr9cipal advantage ( c>borundum ov] su* sub/ances z silicon1 etc41 is t x is n affect$ by ! heavy dis*>ge ( ! transmitt+ app>atus & does n require a new adju/m5t aft] ea* p]iod ( s5d+4 ,all ! cry/als w n "w1 & s a l>ge cake %\ld be pur*as$ & ! desir$ cry/als select$4 ,! d>k blue portions ( ! mass1 :i* are ! h>de/1 w give ! cle>e/ tones 9 ! telephone receiv]s1 & are pref]able to ! light] color$ cry/als4 ,s9ce ! cry/als conduct bett] 9 "o direction ?an 9 ! o!r1 z expla9$ above1 ! adju/m5t mu/ be made ) ! view ( det]m9+ 9 :i* position ! p>ticul> cry/al w "w ! be/4 ,c>borundum w produce s\nds 9 ! telephone receiv]s )\t ! aid ( any batt]y1 b = c>eful "w a batt]y & a pot5tiomet] are necess>y4 ,! o!r cry/als giv5 9 ! column m]ely require t ! telephone receiv]s be connect$ to ! detector t]m9als z 9 ! wir+ diagram 9 ,fig4 #ajh4 ,! ,clapp-,ea/ham detector makes use ( a cry/al ( iron pyrites held 9 a brass reta9+ cup b5ea? ! metal contact po9t4 ,x is n affect$ by /rong signals & requires no batt]y or pot5tiomet]4 ,:5 adju/$ x w rema9 9 a s5sitive condition = a long "t )\t fur!r att5tion4 ,illu/ration3 ,fig4 #ajf4 ,clapp-,ea/ham ,f]ron ,detector4 99,silicon ,detector499--,:ile ! silicon & p]ikon detectors are class$ z m9]al or cry/al detectors !y des]ve special att5tion4 ,illu/ration3 ,fig4 #ajg4 ,silicon ,cry/al 9 ,cup4 ,silicon gives fair results if a cry/al is plac$ betwe5 two metal electrodes z1 = in/ance1 betwe5 ! contact & spr+ ( ! univ]sal detector1 b is mu* m s5sitive :5 prop]ly m\nt$4 ,a brass cup su* z t %[n 9 ,fig4 #ij is made & ! int]ior bright5$ by scrap+ ) a file4 ,! cup is !n p\r$ full ( a molt5 fusible alloy & ! silicon press$ 9 x until x cools & becomes set4 ,x %\ld !n pres5t an appe>ance simil> to t %[n by ,a 9 ,fig4 #ajg4 ,! silicon is gr\nd d[n by rubb+ on ! surface ( a clean oil/one kept well wet ) wat]1 until ! surface is flat & %[s a poli%4 ,illu/ration3 ,fig4 #ajh4 ,silicon ,detector ,circuits4 ,! cup conta9+ ! silicon is plac$ ov] ! hole 9 ! b$plate ( ! univ]sal detector4 ,a knurl$ brass ?umbscrew hav+ a po9t on its l[] end is screw$ into ! coll> on ! spr+1 ,s1 & br\ght to be> on ! poli%$ surface ( ! silicon4 ,! pressure may be easily regulat$ by means ( ! l>ge adju/+ screw until ! signals 9 ! telephone receiv]s are ! l\de/4 ,x is n advisable to fa/5 ! cup to ! b$plate b m]ely to bright5 ! bottom s z to insure a good contact4 ,! cup may !n be mov$ ar\nd s t diff]5t portions ( ! poli%$ surface ( ! silicon may be br\ght into play :5 desirable4 ,if ! knurl$ brass ?umbscrew is fitt$ ) a plat9um po9t :i* c be br\ght to be> on ! surface ( ! silicon1 ! effici5cy ( ! detector w be mat]ially increas$4 ,:5 m\nt+ silicon or o!r cry/als "s c>eless exp]im5t]s use lead or a metal hav+ a high melt+ po9t in/ead ( a fusible alloy4 ,?is is poor policy because ! high temp]ature coats ! surface ( ! cry/als & ! int]ior ( ! cup ) a non-conduct+ lay] :i* de/roys ! s5sitiv5ess & makes x unfit = long di/ance "w4 ,a fusible alloy melt+ at ab\t ! boil+ po9t ( wat] or ev5 l[] %\ld be us$4 ,su* alloys are usually compos$ ( t91 lead & bismu?4 ,! addition ( a little cadmium s]ves to make ! fus+ po9t consid]ably l[] 9 ea* case4 ,! alloys may be prep>$ by ! exp]im5t] f ! foll[+ =mulae1 or are obta9able f a firm manufactur+ fire plugs = automatic fire ext+ui%]s4 ,! lead %\ld be melt$ fir/ & !n ! bismu?1 t9 & cadmium add$ 9 ! ord] nam$4 99,p]ikon ,detector499--,! ,p]ikon detector is "o ( ! late/ types to come into ext5sive use4 ,x consi/s ( two cry/als1 z9cite & *alcopyrites1 set 9 cups 9 ! mann] j describ$ & plac$ 9 contact ) ea* o!r4 ,! m9]als are m\nt$ simil> to ^? 9 ,fig4 #aje4 ,! z9cite %\ld pres5t a r flat surface ) ! gra9 ( ! cry/al p>allel to ! sides ( ! cup s t ! top surface corresponds to ! end ( a /ick ( wood saw$ at "r angles to ! gra94 ,m ?an "o cry/al ( z9cite is usually set 9 ! same cup4 ,! *alcopyrites %\ld pres5t a r blunt po9t4 ,! cup conta9+ ! *alcopyrites is ! small] & is bor$ & ?read$ to fit a ?umbscrew :i* passes ?r\gh ! coll> 9 ! spr+1 ,s1 ( ! univ]sal detector4 ,! bottom ( ! cup conta9+ ! z9cite is bright5$ s z to insure a good contact & !n plac$ on ! b$ plat$ "u ! cup conta9+ ! *alcopyrites :i* is fa/5$ to ! ?umbscrew4 ,! z9cite may !n be mov$ ar\nd until ! mo/ s5sitive portion is f\nd4 ,! *alcopyrites is l[]$ until x comes into contact ) ! z9cite & !n ! pressure regulat$ by means ( ! l>ge adju/+ screw4 ,illu/ration3 ,fig4 #aji4 ,p]ikon ,detector ,elem5ts4 ,! ,p]ikon detector gives excell5t results )\t a batt]y & is pref]ably us$ 9 t mann]4 ,if a batt]y is us$1 a pot5tiomet] to l[] ! voltage is necess>y4 ,:5 adju/+ ?is or ! c>borundum detector :]e a batt]y is us$1 ! pressure mu/ be v c>efully regulat$ until x is f\nd to be ! be/4 ,:5 ! pressure is light ! signals 9 ! phones are due to an imp]fect contact1 & :5 x is slightly increas$ ! rectify+ prop]ties ( ! cry/al are br\ght into play4 ,! ,p]ikon detector illu/rat$ 9 ,fig4 #aaj is some:at simil> to t us$ = comm]cial "w4 ,! /&>ds or po/s support+ ! cups :i* conta9 ! elem5ts are brass rods #a_/b in* squ>e & #a #a_/b in*es high4 ,a hole is bor$ 9 ! bottom ( ea* & ?read$ ) an #h-cb tap to receive a ma*9e screw :i* passes ?r\gh ! base & holds !m 9 an upright position4 ,a hole is bor$ #a #a_/h in*es f ! bottom1 9 ! face ( "o /&>d & ?read$ ) an #h-cb tap4 ,a brass rod #a #a_/d in*es long1 c>ry+ at "o end a cup #a in* 9 diamet] & #c_/h in* deep1 is ?read$ to fit 9 ! hole 9 ! /&>d4 ,! z9cite is m\nt$ 9 ?is cup4 ,illu/ration3 ,fig4 #aaj4 ,p]ikon ,detector4 ,! o!r /&>d is cut 9 half ) a hack saw & a #a_/h-;in* hole bor$ #a_/d in* deep 9 ! axis ( ea* piece4 ,a p91 #a_/b in* long1 is set 9 ! l[] half by sold]+ x 9 ! hole4 ,! upp] half ( ! /&>d is plac$ ov] ! p9 & left free to move :5 twi/$4 ,a #a_/h-;in* brass tube1 #a in* long1 passes ?r\gh ! upp] "p ( ! /&>d4 ,a #a_/h-;in* brass rod1 #a #c_/d in*es long1 passes ?r\gh ! tube4 ,! small cup conta9+ ! z9cite is m\nt$ on "o end ( ! rod & a h>d rubb] h&le on ! o!r4 ,a brass spr+ is plac$ betwe5 ! cup & ! /&>d 9 ord] to press ! *alcopyrites aga9/ ! z9cite4 ,! cup is m\nt$ out ( c5t] s t by revolv+ x & twi/+ ! /&>d at ! same "t ! *alcopyrites may be br\ght into contact ) any portion ( ! z9cite4 ,by screw+ ! rod support+ ! z9cite cup 9 or out ( ! /&>d ! pressure ) :i* ! two elem5ts are press$ toge!r may be regulat$4 ,! base ( ! detector is h>d rubb] ( ! dim5sions indicat$ 9 ! illu/ration4 ,f\r b9d+ po/s on ea* corn] ( ! base are necess>y4 ,! detector is connect$ 9 a simil> mann] to ! silicon detector %[n 9 ,fig4 #ajh4 ,if a batt]y is us$ ! circuit %\ld be l t ( ! b>e po9t electrolytic1 & ! curr5t mu/ fl[ f ! z9cite to ! *alcopyrites4 ,,lead ,,p]oxide ,,detector4 ,! p]oxide ( lead detector makes use ( no liquids1 b /ill may be class$ z an electrolytic s9ce its action is ( t nature4 ,illu/ration3 ,fig4 #aaa4 ,p]oxide ( ,lead ,detector4 ,x consi/s ( a pellet ( lead p]oxide held betwe5 an electrode ( lead & "o ( plat9um4 ,contr>y to mo/ o!r detectors1 ! resi/ance is increas$ ^u ! passage ( electrical oscillations4 ,! oscillations /imulate *emical action & increase a c\nt]-electromotive =ce suffici5tly s t a decrease 9 ! curr5t s5t ?r\gh ! phones by ! local batt]y takes place4 ,! action may be outl9$ m 9 detail z foll[s4 ,! curr5t ( ! local batt]y decomposes "p ( ! lead p]oxide into its compon5ts1 lead & oxyg54 ,! lead ions are positively electrifi$ & s !y t5d to pass upw>d t[>d ! lead electrode :i* is negative4 ,! negative ions ( oxyg5 gas t5d to pass d[nw>ds t[>ds ! plat9um4 ,b ! lead & plat9um electrodes ) ! int]v5+ lead p]oxide con/itute a small cell act+ indep5d5tly ( ! local batt]y & s5d+ a curr5t 9 ! opposite direction4 ,?is c\nt]-electromotive =ce t5ds to s5d ! ions 9 an opposite direction to t 9 :i* !y are s5t by ! batt]y curr5t4 ,^u ! passage ( electrical oscillations ?is c\nt] electromotive =ce is increas$ & suffici5t ions s5t out 9 opposition to ^? ( ! batt]y curr5t s t an appreciable drop 9 ! curr5t fl[+ ?r\gh ! telephone receiv]s takes place4 ,! sudd5 curr5t drop produces a s\nd 9 ! receiv]s4 ,! lead pellets may be secur$ f a druggi/ :o c mold !m 9 8 tablet press4 ,!y %\ld be subject$ to z great a pressure z possible 9 ord] to r$uce resi/ance & prev5t crumbl+4 ,a piece ( plat9um foil ab\t #a_/b in* squ>e is plac$ b5ea? ! pellet on ! cry/al electrode4 ,a piece ( clean1 bright %eet lead #c_/h in* 9 diamet] & #a_/h in* ?ick is laid on ! pellet & ! :ole clamp$ toge!r by tight5+ ! ?umbscrew pass+ ?r\gh ! coll> on ! spr+1 ,s4 ,! detector is connect$ up simil> to ! b>e po9t1 ,! plat9um is made ! positive ( ! local batt]y4 ,adju/m5t is secur$ by regulat+ ! pressure4 ,x is v necess>y t ! pellets be kept dry1 z o!rwise a l\d s++ & hiss+ noise1 due to ! decomposition ( ! wat]1 w r5d] ! reception ( signals v difficult4 ,,! ,,m>coni ,,magnetic ,,detector4 ,:5 an oscillatory dis*>ge takes place ?r\gh a coil ( wire surr\nd+ a ne$le1 x magnetizes ! ne$le 9 a totally diff]5t mann] f a voltaic curr5t4 ,! ne$le w h sev]al poles ?r\gh\t its l5g?1 _m ( !m rev]s$4 ,ru!r=d appli$ ?is ph5om5on to ! detection ( electrical oscillations1 b x rema9$ = ,m>coni to improve x & give ! magnetic detector its exi/+ =m4 ,?is type ( detector is v s5sitive1 free f all adju/m5t & is n made inop]ative by ! heavi] dis*>ge ( ! transmitt] dur+ ea* p]iod ( s5d+4 ,illu/ration3 ,fig4 #aab4 ,m>coni ,magnetic ,detector4 ,a small trans=m] is provid$ ) a core compos$ ( a b& or cord ( iron wires 9 ! =m ( an endless belt :i* passes ar\nd two pulleys kept 9 motion by a clockwork motor4 ,! b& revolves 9 ! field ( a /rong horse%oe magnet & passes directly ov] ! poles aft] issu+ f ! trans=m] bobb91 s t ! portion approa*+ ! bobb9 are con/antly 9 a /ate ( increas+ magnetism4 ,! actual op]ation is bas$ ^u ! prop]ty ( iron call$ hy/]esis1 = ! magnetism ( ! core lags beh9d t ( ! p]man5t magnet & is ( a diff]5t degree f :at x ought to be1 9 view ( its position 9 ! vic9ity ( ! p]man5t magnet4 ,! mom5t ! oscillations pass ?r\gh ! prim>y coil ( ! trans=m]1 ?is lag is set free & ! magnetism assumes its full value4 ,! *ange 9 magnetism induces a curr5t 9 ! second>y1 :i* regi/]s z a s\nd 9 ! telephone receiv]s4 ,illu/ration3 ,fig4 #aac4 ,details ( ,trans=m]4 ,! prim>y coil is made up ( a s+le lay] ( ,no4 #cf ,b4 ,s4 gauge silk cov]$ wire w\nd on a ?9 wall$ glass or h>d rubb] tube4 ,! ends ( ! tube1 :i* is #b in*es long & #a_/d in* ext]nal diamet]1 are slightly fl>$ s z n to *afe ! b&4 ,! prim>y is ?or\ghly %ellack$ & cov]$ ) a s+le lay] ( pap]4 ,! second>y is also ( ,no4 #cf ,b4 ,s4 silk cov]$ wire & is w\nd betwe5 two disks ( h>d rubb]1 #a_/d in* ?ick & #a #a_/b in*es 9 diamet]1 plac$ #c_/h in* ap>t 9 ! c5t] ( ! second>y & ! int]v5+ space w\nd full ( wire4 ,! t]m9als ( bo? ! prim>y & second>y are ext5d$ to b9d+ po/s m\nt$ on ! case ( ! in/rum5t4 ,illu/ration3 ,fig4 #aad4 ,me?od ( ,jo9+ ,ends ( ,b&4 ,! core or revolv+ b& is made by w9d+ #ajj /r&s ( ,no4 #cf silk cov]$ s(t iron wire betwe5 two small pegs1 plac$ a di/ance ap>t1 equal to twice ! circumf]5ce ( ! oval =m$ by ! two pulleys4 ,! wire is all w\nd 9 ! same direction4 ,x %\ld be c>efully remov$ f ! pegs & kept taut :ile x is slightly twi/$1 d\bl$1 & !n fur!r twi/$ into a rope or cord4 ,! ends are ?read$ toge!r ) a sep>ate piece ( insulat$ wire1 into a l9k :i* w pass easily ?r\gh ! prim>y tube4 ,illu/ration3 ,fig4 #aae4 ,pulley4 ,! pulleys ar\nd :i* ! b& revolves are made ( h>d wood4 ,!y are #d in*es 9 diamet] & #c_/h in* ?ick & h a ,v-%ap$ groove cut 9 ! edge4 ,9 ord] to m9imize friction & we>1 x is advisable to fit !m ) a be>+ :i* may be made out ( brass tub+ & a c\ple ( wa%]s4 ,"o ( ! pulleys is ge>$ to a clockwork motor s t ! b& makes a complete revolution ab\t once e two m9utes4 ,an old eight day clock may be adapt$ = ?is purpose1 or1 :at is mu* bett]1 ! motor f an old phonograph4 ,illu/ration3 ,fig4 #aaf4 ,pulley ,be>+s4 ,! horse%oe magnet is m\nt$ ) its nor? pole po9t+ t[>ds & ne>ly t\*+ ! middle ( ! outside ( ! second>y4 ,! s\? pole is plac$ opposite ! end ( ! prim>y tube :i* is on ! side t[>ds :i* ! b& is revolv+1 t is1 ! b& 9 revolv+ passes fir/ ov] ! nor? pole & !n ov] ! s\?4 ,two magnets are sometimes us$ ) _! nor? poles toge!r 9 ! c5t] ( ! second>y1 & a s\? pole opposite ea* end ( ! prim>y tube4 ,illu/ration3 ,fig4 #aag4 ,circuit ( ,magnetic ,detector4 ,! comm]cial in/rum5t is plac$ 9 a glass cov]$ case :i* protects x f du/ & injury4 ,! clockwork motor is conceal$ 9 ! l[] "p ( ! case4 ,?is is a good plan b an exp]im5tal detector may be m]ely m\nt$ on a flat wood5 base z illu/rat$ 9 ,fig4 #aab4 ,! second>y t]m9als are connect$ directly to ! telephone receiv]s :ile ! prim>y leads to ! a]ial & ! gr\nd4 ,:5 ! detector is />t$ up x %\ld make a v slight hiss+ s\nd 9 ! telephone receiv]s z ! b& passes sl[ly ?r\gh ! coils4 ,?is %[s ! in/rum5t to be 9 good work+ ord] & ready = ! reception ( signals4 99,! ,audion499--,dr4 ,lee ,de,forest 0 l$ by ! flick]+ ( a s5sitive gas flame to inve/igate :e!r or n x w\ld respond to ,h]tzian vibrations z well z to ^? ( heat & s\nd4 ,8 exp]im5ts l$ to ! inv5tion ( ! audion1 a peculi> in/rum5t mak+ use ( ioniz$ gas = its op]ation4 ,! audion consi/s ( an inc&esc5t lamp hav+ a metallic filam5t1 on ei!r side ( :i* are a grid & a plate made ( nickel4 ,:5 ! filam5t is light$ x ?r[s (f ions :i* act z a relay to high frequ5cy oscillations pass+ betwe5 ! plate & ! grid4 ,a prop]ly con/ruct$ audion is exce$+ly s5sitive & produces v l\d tones 9 ! telephone receiv]s4 ,x has ! fur!r advantages ( entire abs5ce ( adju/m5t except ! gov]n+ ( ! batt]y voltage1 & is capable ( extremely f9e tun+4 ,illu/ration3 ,fig4 #aah4 ,flem+ ,oscillation ,valve4 ,flem+ orig9at$ ! oscillation valve illu/rat$ 9 ,fig4 #aah4 ,x consi/s ( an ord9>y inc&esc5t lamp ) a c>bon filam5t1 hav+ a metal cyl9d]1 ,c1 plac$ ar\nd ! filam5t1 b atta*$ to an indep5d5tly insulat$ plat9um wire seal$ 9 ! glass4 ,:5 ! lamp is light$ by pass+ a curr5t ?r\gh ! filam5t1 ! inc&esc5t c>bon lib]ates negative ions4 ,if oscillations are !n set up 9 a circuit :i* includes a pair ( s5sitive telephone receiv]s & is =m$ by connect+ ! negative t]m9al ( ! filam5t ) ! plat9um cyl9d]1 negative electricity w be enabl$ to pass f ! filam5t to ! cyl9d] b n 9 ! opposite direction1 & s s\nds w be produc$ 9 ! telephone receiv]s4 ,high frequ5cy oscillations !mselves c\ld n be made to pass ?r\gh ! telephone receiv]s because ( ! *ok+ action ( ! iron cores ( ! electromagnets4 ,illu/ration3 ,fig4 #aai4 ,flame ,audion4 ,! simple b s5sitive =m ( detector illu/rat$ 9 ,fig4 #aai is n ( practical value = comm]cial "w1 b is v int]e/+ z ! prog5itor ( ! audion1 & provides a good field = amateur inve/igation4 ,its only drawback is t ! gas flame is v difficult to keep /eady & e flick] regi/]s z a s\nd 9 ! telephone receiv]s4 ,a ,buns5 burn] us+ coal gas furni%es ! flame1 & a salt ( an alkal9e metal heat$ 9 ! flame1 ! ions4 ,! hydroxides ( caesium1 potassium & sodium give ! be/ results 9 ! ord] nam$4 ,! salt is conta9$ 9 a piece ( tr\gh-%ap$ plat9um foil1 ab\t #c_/h in* long & #a_/af in* wide4 ,?is tr\gh is made ! ca?ode or negative ( ! telephone circuit & plac$ 9 ! out] oxidiz+ flame j above its juncture ) ! int]ior r$uc+ flame & mu/ be kept inc&esc5t4 ,! upp] electrode or anode is a piece ( plat9um wire ab\t #a_/af in* above ! tr\gh4 ,illu/ration3 ,fig4 #abj4 ,circuit ( ,flame ,audion4 ,! arrangem5t & con/ruction ( ! detector is cle>ly indicat$ by ! draw+ s t x is unnecess>y to g into details4 ,! block1 ,e1 :i* fits on ! tube ( ! ,buns5 burn]1 is made ( fib]4 ,two d\ble b9d+ po/s1 ,d1 are fa/5$ to ,e to support ! rods1 ,r1 :i* are fitt$ at ! tops ) b9d+ po/s1 ,b1 into :i* ! electrodes may be clamp$4 ,twelve dry cells are connect$ ) a multiple po9t swit* s t an electromotive =ce ( #f-ah volts1 v>y+ 9 /eps ( "o cell at a "t1 may be secur$4 ,! flame is be/ provid$ ) a mica *imney to protect x f drafts4 ,by keep+ pl5ty ( salt 9 ! tr\gh & c>efully adju/+ ! voltage1 ?is detector may be made m>vel\sly s5sitive4 ,! diff]5t detectors 9 ord] ( _! s5sitiv5ess are electrolytic1 p]ikon1 magnetic1 silicon1 c>borundum4 ,peacock ore or bornite1 :i* consi/s ( ab\t #fj p>ts ( copp]1 #ad p>ts ( iron & #bf p>ts ( sulphur1 may be sub/itut$ = ! *alcopyrites ) excell5t results4 ,,*apt] ,,xiv4 ,,tun+ ,,coils ,,& ,,trans=m]s4 ,a tun+ coil is m]ely a v>iable inductance w\nd 9 s+le lay] on a suitable =m4 ,fig4 #aba illu/rates a d\ble slide tun]4 ,! base is a piece ( h>d wood1 #ab in*es long1 #a in* ?ick & #e #a_/b in*es wide4 ,two wood5 heads #d x #d x #c_/d in*es support ! =m ^u :i* ! coil is w\nd4 ,illu/ration3 ,fig4 #aba4 ,d\ble-slide ,tun+ ,coil4 ,! =m is a piece ( wood5 curta9 pole1 #i in*es long & #c in*es 9 diamet]4 ,"s may pref] to use a c>dbo>d tube 9 place ( ! curta9 pole4 ,a tube c be made by w9d+ a long /rip ( c>dbo>d #i in*es wide ar\nd a suitable =m & cem5t+ ! lay]s toge!r ) %ellac4 ,! lib]al use ( %ellac w /iff5 ! tube & cause x to bett] reta9 its %ape4 ,! tube is held tightly betwe5 ! two heads by means ( a brass rod :i* passes ?r\gh ! c5t] & is clamp$ by two nuts4 ,a squ>e brass rod #aj #a_/b in*es long is fa/5$ to ! c5t] ( ! top ( ! heads & a simil> rod to ! c5t] ( ! front face4 ,illu/ration3 ,fig4 #abb4 ,slid]s4 ,fig4 #abb %[s two =ms ( slid]s4 ,! fir/ "o is ! bett] & to be pref]r$4 ,a %ort squ>e brass tube1 ,s1 fits snugly ^u ! squ>e brass rod1 ,r4 ,x _c turn ar\nd b is free to slide back & =?4 ,a /rip ( spr+ brass1 ,c1 is sold]$ to ! l[] face ( ! squ>e tube4 ,x is b5t 9 a d\ble turn & a pun* m>k made ne> ! l[] end z %[n 9 ! illu/ration4 ,! ind5tation is made ) a c5t] pun*1 b %\ld n be deep en\gh to break ?r\gh ! metal4 ,illu/ration3 ,fig4 #abc4 ,d\ble-slide ,tun+ ,coil ,circuits4 ,! little projection on ! "u side ( ,c caus$ by ! pun* m>k is ! only "p ( ! slid] :i* %\ld make contact ) ! wire on ! tun+ coil4 ,x %\ld slide easily b firmly along ! wires & t\* only "o at a "t4 ,long di/ance signals w be consid]ably weak5$ if ! slid] t\*es m ?an "o wire at a "t & %ort-circuits a turn4 ,illu/ration3 99,plate ,,iv4 ,receiv+ ,circuits4 7,/raightaway ,a]ial4799 ,! slid]1 ,b1 is simil> to ,a except t x has a %ort l5g? ( brass tub+1 ,t1 sold]$ to ! "u side ( ,s 9 place ( ! brass /rip1 ,c4 ,a small ball be>+ :i* j fits ! bore ( ! tube is pu%$ d[n into contact ) ! wire by means ( a small spiral spr+ inside ( ! tube4 ,bo? slid]s are fitt$ ) a h>d rubb] h&le s t !y may be adju/$ )\t ! r+]s com+ into contact ) ! metal4 ,illu/ration3 ,fig4 #abd4 ,murdock ,d\ble-slide ,tun+ ,coil4 ,illu/ration3 ,fig4 #abe4 ,unit$ ,wireless ,receiv+ ,set4 ,two good circuits employ+ ! d\ble slide tun] are giv5 9 ,fig4 #abc4 ,plates ,,iv & ,v illu/rate ! oscillation or tun+ circuits ( ! mo/ prom95t receptor sy/ems4 ,if a loop a]ial is us$1 m ?an "o tun+ coil is necess>y z %[n by ! loop a]ial oscillation circuits 9 ,plate ,v4 ,figs4 #abe & #abf illu/rate ! in/rum5ts employ$ = receiv+ by ! ,unit$ ,wireless ,company4 ,illu/ration3 ,fig4 #abf4 ,unit$ ,wireless ,portable ,receiv+ ,set4 ,9 ,fig4 #abe ! h&les :i* are atta*$ to ! slid]s ( ! tun+ coils project ?r\gh long slots cut 9 ! top & "o side ( ! cab9et4 ,! tun+ coils 9 ! portable outfit are m\nt$ 9 a v]tical position 9 back ( ! a]ial swit*4 99,loosely ,c\pl$ ,tun+ ,coil499--,by ! use ( a loosely c\pl$ receiv+ tun] or trans=m]1 ! range ( a /ation is consid]ably increas$1 z is also ! /r5g? ( ! signals1 & mu* f9] tun+ & selectivity made possible4 ,fig4 #abg illu/rates ! con/ruction ( su* an oscillation trans=m]4 ,! base is wood & measures #ad x #e #a_/b x #a in*es4 ,! prim>y w9d+ is w\nd on a c>dbo>d or fib] tube #d #a_/d in*es long1 hav+ an int]nal diamet] ( #b #c_/d in*es & an ext]nal diamet] ( #c in*es4 ,! heads1 ,l & ,m1 are ! same size z ^? ( ! d\ble slide tun+ coil4 ,! head1 ,l1 has a circul> hole #b #c_/d in*es 9 diamet] cut 9 ! c5t] 9 ord] to p]mit ! second>y coil to slide 9 & out ( ! prim>y4 ,illu/ration3 ,fig4 #abg4 ,oscillation ,trans=m]4 ,! second>y coil is a piece ( r\nd curta9 pole #b #a_/b in*es 9 diamet] & #c in*es long4 ,a #e_/af-;in* hole is bor$ ?r\gh its axis4 ,! head1 ,k1 ( ! second>y coil is #c #c_/d x #c #c_/d x #c_/d in*es4 ,a t5-po9t swit* on ,k is s connect$ t x divides ! second>y into t5 equal p>ts & p]mits any numb] ( ! divisions to be us$ z desir$4 ,illu/ration3 ,fig4 #abh4 ,unit$ ,wireless ,receiv+ ,trans=m]4 ,a wood5 po/1 ,j1 #b #a_/b in*es high & #a #a_/d in*es wide1 supports "o end ( a #a_/d-;in* brass rod ^u :i* ! second>y slides back & =?4 ,illu/ration3 ,fig4 #abi4 ,details ( ,receiv+ ,trans=m]4 ,no4 #bd ,b4 ,s4 gauge copp] wire may be us$ = w9d+ bo? ! prim>y & second>y4 ,x is also ! prop] size to use on ! d\ble slide tun]4 ,! be/ me?od is to use b>e wire1 w\nd ) a ?read s t a ?read is int]pos$ betwe5 adjac5t turns ( ! w9d+4 ,give ! :ole w9d+ "o or two coats ( ?ick %ellac & all[ x to h>d54 ,!n use a /rip ( s&pap] to remove ! %ellac 9 a long n>r[ pa? imm$iately bel[ ! slid]s s t !y may make contact ) ! wire4 ,illu/ration3 ,fig4 #acj4 ,slid] = ,loose ,c\pl]4 ,"s may pref] to make a loosely c\pl$ tun] 9 :i* ! inductance ( bo? coils is adju/able by means ( a slid+ contact4 ,9 su* a case ! slid] on ! second>y coil mu/ be con/ruct$ z illu/rat$ 9 ,fig4 #acj4 ,! contact is long & n>r[ s t x c t\* ! inn]mo/ turns1 :5 plac$ )9 ! prim>y4 ,by slipp+ ! slid] (f ! end ( ! rod & rev]s+ x1 ! contact c be made to t\* ! turns next to ! head4 ,! squ>e brass rod is set 9 a not* cut 9 ! coil head s t ! rod is flu% ) ! top4 ,:5 tun+ a receiv+ trans=m]1 place bo? v>iable cond5s]s 9 a halfway position & adju/ ! slid+ contacts1 fir/ on ! prim>y & !n on ! second>y1 until ! signals are ! l\de/4 ,!n adju/ ! cond5s]s4 ,illu/ration3 ,fig4 #aca4 ,loosely ,c\pl$ ,tun+ ,circuits4 ,to cut out an undesirable /ation1 v>y ! c\pl+ betwe5 ! two coils by slid+ ! second>y away f ! prim>y4 ,:5 sev]al turns on ! second>y seem to give ! same results also v>y ! c\pl+4 ,illu/ration3 ,fig4 #acb4 ,comb9ation ,loosely & ,closely ,c\pl$ ,tun]4 ,fig4 #acb illu/rates ! wir+ diagram ( a comb9ation loosely & closely c\pl$ tun]4 ,two slid+ contacts are plac$ on ! prim>y coil ( ! receiv+ trans=m] & connect$ ) a d\ble pole d\ble ?r[ swit* z 9 ! diagram4 ,:5 ! swit* is ?r[n on contacts #a & #b1 ! prim>y is connect$ to ! detector z a d\ble slide tun]1 & :5 on #c & #d bo? ! prim>y & second>y are br\ght into use z a trans=m]4 ,?is arrangem5t may seem cumb]some & is recomm5d$ only z a conv5i5ce 9 exp]im5t+4 ,a loosely c\pl$ tun+ coil is capable ( exact tun+1 & unless "o und]/&s h[ to use x1 he may n he> a /ation because ! tun] is n prop]ly adju/$4 ,by us+ ! d\ble slide tun] fir/ & !n ?r[+ ! swit* s z to tune 9 on ! trans=m]1 ?is difficulty may be elim9at$4 ,illu/ration3 ,fig4 #acc4 ,clapp-,ea/ham ,loose ,c\pl]4 99,pot5tiomet]499--,a pot5tiomet] is n prop]ly class$ "u ! head+ ( tun+ coils1 b ! con/ruction may be made s simil> t x well appe>s "h4 ,! pot5tiomet] is m]ely a v>iable resi/ance %unt$ across ! t]m9als ( ! detector batt]y 9 ! mann] illu/rat$ 9 ! num]\s detector circuits4 ,x is us$ to r$uce ! voltage ( ! batt]y to a value slightly bel[ ! critical voltage ( ! detector4 ,! critical voltage ( a detector is ! voltage at :i* its action comm5ces4 ,9 ! case ( an electrolytic detector1 x is ! voltage requir$ to break d[n ! ?9 film ( gas :i* collects on ! b>e po9t4 ,illu/ration3 ,fig4 #acd4 ,a ,highly ,effici5t ,=m ( ,loose ,c\pl]4 ,9 con/ruction1 ! pot5tiomet] illu/rat$ 9 ,fig4 #ace is 9 reality a small edition ( a d\ble slide tun+ coil4 ,x is w\nd ) ,no4 #bh ,b4 ,s4 gauge ,g]man silv] wire4 ,?ree b9d+ po/s are m\nt$ on ! base1 two ( !m connect+ ) ! ends ( ! coil & "o ) ! slid+ contact4 ,illu/ration3 ,fig4 #ace4 ,pot5tiomet]4 ,9 a f9ely balanc$ circuit :]e long di/ance "w & close tun+ are desir$1 ! pot5tiomet] mu/ be non-inductive4 ,illu/ration3 ,fig4 #acf4 ,amco ,pot5tiomet]4 ,?is may be accompli%$ by us+ two pot5tiomet]s w\nd 9 opposite directions f "o ano!r & connect$ 9 s]ies4 ,! two t]m9als ( ! w9d+s are !n connect$ across ! batt]y & ! slid+ contacts l$ to ! detector4 ,illu/ration3 99,plate ,v4 ,receiv+ ,circuits499 ,,*apt] ,,xv4 ,,receiv+ ,,cond5s]s4 ,cond5s]s play an important "p 9 tun+ & adju/+ ! receiv+ circuits ( a wireless telegraph /ation4 ,!y are ins]t$ 9 ! circuits = v>i\s purposes4 ,9 "s places a small cond5s] %unts ! detector to some:at equalize any small *anges 9 capacity :i* might occur 9 ! detector & ?r[ ! circuit out ( tune4 ,9 o!r cases :]e selectivity is desir$ !y provide a pa? = undesirable oscillations & all[ !m to fl[ into ! gr\nd )\t pass+ ?r\gh ! detector4 ,:]ev] ! d\ble slide tun] or ! ,fess5d5 s+le slid] circuit is us$1 a cond5s] mu/ be ins]t$ 9 ! circuit to prev5t ! wire ( ! tun+ coil f %ort-circuit+ ! telephone receiv]s & batt]y4 ,illu/ration3 ,fig4 #acg4 ,tun+ ,circuit ) & )\t an ,adju/able ,cond5s]4 ,! value ( a cond5s] may be readily appreciat$ by ! foll[+ exp]im5t4 ,connect up a detector accord+ to ! diagram %[n by ,a ( ,fig4 #acg4 ,?is circuit w give good results & ! signals w be cle>4 ,b *ange x to t %[n 9 ,b1 by connect+ "o side ( a v>iable cond5s] to ! upp] contact ( ! tun+ coil & lead+ ! o!r side to ! gr\nd4 ,consid]able selectivity may n[ be atta9$ & ! signals w be #ej p] c5t l\d]4 ,to be ( any value = a receiv+ circuit ! capacity ( ! cond5s] mu/ be adju/able1 b !re are _m places :]e a fix$ cond5s] is ( s]vice4 ,! av]age capacity ( su* cond5s]s g5]ally ranges ar\nd 4#jjc ( a micr(>ad1 b _c be pr$et]m9$1 z x dep5ds ^u _m factors :i* v>y greatly 9 diff]5t /ations4 ,ev5 if specific dim5sions 7 giv5 = ! con/ruction ( a pap] cond5s] ( /at$ capacity1 ! exp]im5t] w\ld v seldom succe$ 9 con/ruct+ 8 cond5s] & h x ( ?is value :5 f9i%$4 ,! pap] us$ z ! dielectric & ! pressure appli$ to ! cond5s] w\ld make ! diff]5ce4 ,! be/ plan is to build "o up 9 ! =m ( a roll z foll[s4 ,?ree ?9 t9 foil /rips #c #a_/b in*es wide & f\r feet long are sep>at$ by /rips ( ?9 p>aff9$ pap] #d in*es wide & f\r & "o-half feet long4 ,! two outside /rips ( t9 foil are connect$ toge!r & =m "o t]m9al ( ! cond5s]4 ,! middle /rip ( t9 foil is ! o!r4 ,! outside /rips ( t9 foil are cov]$ ) p>aff9$ pap] & ! :ole roll$ up4 ,if ?9 pap] & t9 foil are us$ ! cond5s] w =m a roll #d in*es long & less ?an an in* 9 diamet]4 ,two or ?ree su* cond5s]s %\ld be con/ruct$1 & "o ( !m connect$ up 9 ! circuit :]e x is desirable to use x4 ,by unroll+ a little ( ! cond5s] & cutt+ "o or two in*es (f at a "t ! prop] size may be det]m9$4 ,z expla9$ 9 ,*apt] ,,vii1 two equal cond5s]s connect$ 9 s]ies h "o-half ! capacity ( ei!r4 ,by connect+ !m 9 p>allel ! capacity is ! sum ( ! two4 ,9 ?is mann] x is n h>d to fir/ f9d ! approximate capacity1 :i* gives ! be/ results be=e cutt+ ! cond5s]4 ,illu/ration3 ,fig4 #ach4 ,tubul> ,cond5s]4 ,:5 ! prop] value is f\nd1 place ! cond5s] 9 a brass tube ab\t #e in*es long & #a in* 9 diamet]4 ,! tube is fitt$ ) h>d rubb] flanges to close ! ends4 ,a b9d+ po/ is m\nt$ on ea* flange1 & connects ) ! t]m9al ( ! cond5s] to :i* x is ne>e/4 ,m\nt+ a cond5s] 9 ?is mann] gives x a mu* bett] appe>ance & x occupies less space ?an o!rwise4 ,fix$ cond5s]s are us$ 9 two cases only1 to %unt ! cond5s] & to prev5t ! tun+ coil f %ort-circuit+ ! telephone receiv]s4 ,9 any o!r position !y are wor?less4 99,v>iable ,cond5s]s499--,a simple =m ( adju/able cond5s] :i* may be quickly made = a special exp]im5t is con/ruct$ 9 ! foll[+ mann]4 ,a wood5 curta9 pole #b in*es 9 diamet] & #ah in*es long is cov]$ ) a lay] ( t9 foil4 ,! t9 foil mu/ be laid on smoo?ly & cem5t$ ) %ellac4 ,a lay] ( p>aff9$ pap] is !n plac$ ov] ! t9 foil4 ,a piece ( %eet copp] or t9 #f #c_/d in*es wide & #ah in*es long is roll$ up 9 a cyl9d] to fit ov] ! rod ) its t9 foil & pap]4 ,! rod is fa/5$ at "o end to a base bo>d ab\t #bj in*es long & #d in*es wide1 by means ( a bracket1 or x may be m\nt$ on a small] base 9 a v]tical position4 ,connections are made to ! t9 foil & to ! outside metal tube4 ,by slid+ ! tube back & =? on ! rod ! cond5s] may be giv5 a v>iable capacity4 ,illu/ration3 ,fig4 #aci4 ,v>iable ,cond5s]4 ,! be/ v>iable cond5s]s are con/ruct$ s t ! dielectric betwe5 ! two plates is =m$ by air4 ,!re are consequ5tly no losses ( en]gy 9 ! cond5s]1 = ?is mode ( con/ruction elim9ates all dielectric hy/]esis4 ,fig4 #aci %[s su* a v>iable cond5s] & ,fig4 #adj ! details4 ,x is possible to d v close1 selective tun+ ) ?is in/rum5t4 ,! effici5cy ( ! receiv+ circuit may be consid]ably improv$ if "o is us$ :]ev] a cond5s] is requir$4 ,a rectangul> box is built up 9 ! mann] %[n 9 ,fig4 #ace4 ,! sides1 ,d1 are #f in*es long1 #d #aa_/af in*es wide & #a_/b in* ?ick4 ,! top1 ,a1 is #f in*es long1 #a #ac_/af in*es wide & #a_/b in* ?ick4 ,! bottom1 ,b1 has ! same wid? & ?ickness b is #aa in*es long4 ,elev5 grooves are cut 9 ,a & ,b z %[n 9 ! cross section4 ,! grooves are #a_/af in* wide1 #c_/af in* deep & #a_/af in* ap>t4 ,!y are =m$ by sett+ ! blade ( a circul> saw s t x projects #c_/af in* above ! table or b$4 ,aft] cutt+ "o groove1 ! guide is mov$ #a_/h in* & ano!r cut made4 ,illu/ration3 ,fig4 #adj4 ,details ( ,v>iable ,cond5s]4 ,elev5 metal plates1 ,p1 are requir$1 six fix$ & five movable4 ,!y are made ( ,no4 #bb gauge %eet brass & measure #d x #f in*es4 ,six ( !m are plac$ 9 ! grooves 9 ! box 9 su* a mann] t an empty groove is left betwe5 ea* "o4 ,! six plates are !n electrically connect$ toge!r by sold]+ a /rip ( brass across _! re> ends4 ,illu/ration3 ,fig4 #ada4 ,slid+ ,plate ,v>iable ,cond5s]4 ,five slots ea* #a_/d in* deep & #a_/d in* ap>t are made ) a hack saw 9 a piece ( brass1 ,c1 #a #a_/b in*es long1 #c_/d in* wide & #a_/b in* ?ick4 ,a small p9 #a_/b in* long is set 9 ! c5t] ( ,c on ! opposite side f ! saw cuts4 ,a fib] h&le #a_/b in* 9 diamet] & #a #a_/b in*es long is fa/5$ to ! p94 ,! five movable brass plates are set 9 ! grooves betwe5 ! six fix$ plates4 ,!y are all[$ to project ?ree or f\r in*es out ( ! box4 ,! yoke1 ,c1 is !n sold]$ across ! ends s t ea* "o ( ! movable plates fits into its correspond+ saw cut4 ,! capacity ( ! cond5s] is v>i$ by slid+ ! movable plates back & =? betwe5 ! fix$ plates4 ,a b9d+ po/ is sold]$ to ! yoke1 ,c1 & ano!r "o to ! /rip :i* holds ! fix$ plates toge!r4 ,connections are made to ! b9d+ po/s ) lamp cord or "s o!r flexible conductor :i* w n int]f]e ) ! movem5t ( ! plates4 ,! in/rum5t is f9i%$ by /a9+ ! woodwork & giv+ x a coat ( v>ni% or %ellac4 ,,*apt] ,,xvi4 ,,telephone ,,receiv]s ,,& ,,headb&s4 ,a pair ( high resi/ance telephone receiv]s 9 nice adju/m5t con/itute "o ( ! mo/ s5sitive electrical in/rum5ts 9 exi/5ce & w detect an exce$+ly weak curr5t4 ,! only type ( receiv] ( mu* s]vice 9 wireless telegraphy is t kn[n z a wat* case or pony receiv]4 ,x is small & compact s t x may be atta*$ to a headb& & clamp$ aga9/ ! e>4 ,illu/ration3 ,fig4 #adb4 ,types ( ,p]man5t ,magnets4 ,! p]man5t magnets ( a wat*-case receiv] are usually 9 ! =m ( ei!r a r+ or a horse%oe z %[n by ,fig4 #adb4 ,! fir/ =m has consequ5t poles & is consid]$ some:at sup]ior to ! horse%oe1 s9ce ! l9es ( =ce are n s liable to pass across ! pole pieces be=e !y pass ?r\gh ! electromagnets & ! diaphragm4 ,! ord9>y l[ resi/ance telephone receiv] is p]fectly well suit$ to ! telephone "w = :i* x 0 design$ & adju/$1 & w give good s]vice on a wireless receptor = %ort di/ances1 b c be consid]ably improv$ by foll[+ ! sugge/ions & in/ructions giv5 bel[4 ,! pr9cipal objection to ! ord9>y receiv] is t x does n conta9 en\gh turns ( wire on its bobb9s4 ,?is is easily rem$i$ by c>efully rew9d+ !m ) a v f9e silk cov]$1 pure copp] magnet wire no l>g] ?an ,no4 #dj ,b4 ,s4 gauge4 ,?is w increase ! numb] ( turns & also ! resi/ance1 b x mu/ n be inf]r$ t resi/ance is to be desir$4 ,?is is a common impression ( amateurs :o d n und]/& ! und]ly+ pr9ciple1 t ! /r5g? ( an electromagnet v>ies directly z ! numb] ( turns ( wire1 multipli$ by ! amp]es fl[+ ?r\gh ! magnet4 ,:5 a telephone receiv] is w\nd ) a f9] wire ! resi/ance is increas$1 cutt+ d[n bo? ! curr5t & ! /r5g? ( ! magnet4 ,b if pure copp] wire is us$1 & ! w9d+ n c>ri$ beyond ! po9t :]e ! circumf]5ce ( ! outside lay] becomes twice z great z ! circumf]5ce ( ! fir/ lay]1 ! numb] ( turns increases fa/] ?an ! resi/ance & ! magnet /r5g? is consid]ably great] ?an be=e ! receiv] 0 rew\nd4 ,no4 #dj ,b4 ,s4 gauge silk cov]$ wire is (t5 us$ = ?is purpose1 b ! be/ results are obta9$ ) enamel$ cov]$ wire ( ! same size4 ,x is possible to w9d almo/ ?ree times z mu* ( ! enamel$ wire on a telephone bobb9 z silk wire ( ! same size4 ,! diff]5ce is due to ! ?ickness ( ! insulation4 ,an ord9>y d\ble pole wat*-case receiv] w h a resi/ance ( #hjj-a1jjj ohms :5 w\nd ) silk cov]$ wire & #a1ejj-a1hjj ohms :5 w\nd ) enamel$ wire4 ,to rew9d a telephone receiv]1 fir/ unscrew ! cap & remove ! diaphragm1 !n remove ! bobb9s by unloos5+ ! screws ) ! aid ( a screw driv]4 ,unw9d ! old wire & exam9e ! empty bobb9s to see t :]ev] ! wire is liable to come into contact ) ! metal t x is well insulat$ ) p>aff9$ pap] or "s o!r equally good mat]ial4 ,!n w9d ! new wire on 9 smoo? ev5 lay]s & :5 x is complet$ fa/5 ! bobb9s back on ! p]man5t magnets & connect !m up4 ,! curr5t %\ld fl[ ?r\gh 9 opposite directions s t ! nor? pole ( "o & ! s\? pole ( ! o!r is on top4 ,d n tru/ splice connections b sold] !m us+ acid z a flux4 ,! ,navy ,dep>tm5t specifies t its wireless receiv]s %all be w\nd ) copp] wire ( n less ?an #j4jjae in* 9 diamet] & ! diaphragm to h a diamet] ( #a #c_/d in*es & a ?ickness ( #j4jjd in*4 ,! resi/ance ( ! coils is specifi$ at #a1jjj-a1ajj ohms4 ,!re is n mu* advantage 9 greatly exce$+ ! numb] ( turns possible ) ?is w9d+1 = to obta9 !m a mu* f9] wire ?an ,no4 #dj ,b4 ,s4 gauge is necess>y & ! ratio betwe5 resi/ance & turns becomes great]4 ,! second objection to ! ord9>y receiv] is t ! diaphragms are v (t5 too ?ick4 ,a receiv] hav+ a ?9 diaphragm is pref]able because :5 a weak curr5t is s5t ?r\gh ! coils1 ! *ange 9 magnet /r5g? is great]4 ,b ?is may be c>ri$ to excess & ! diaphragm made s ?9 t x _c absorb suffici5t l9es ( =ce to prop]ly play its "p4 ,! be/ ?ickness !n = a diaphragm c only be det]m9$ exp]im5tally & dep5ds mu* ^u ! diamet]4 ,! di/ance f ! poles & ! /r5g? ( ! magnets w also h consid]able be>+ on ! ?ickness4 ,! ord9>y phone w be v s5sitive & give cle> tones ) diaphragms rang+ f 4#ja-4jjd in*4 ,! relation betwe5 ! ?ickness & ! diamet] is %[n by ! foll[+3 ,if ! diaphragm ( a receiv] is increas$ 9 diamet]1 ! tones w become m di/9ct1 b if ! increase is c>ri$ too f> !y w become indi/9ct & ! only rem$y is to ?ick5 ! diaphragm4 ,likewise if aft] cle>ness is secur$ ! diaphragm is ?ick5$ s t ! tones aga9 become indi/9ct1 ! diamet] mu/ be increas$4 ,illu/ration3 ,fig4 #adc4 ,gr9d+ ,tool4 ,! ?ird objection is t su* receiv]s are n c>efully & prop]ly adju/$4 ,! adju/m5t is also a matt] ( exp]im5t & is accompli%$ by comp>ison ( ! receiv] 9 "q ) "o :i* is kn[n to be 9 a s5sitive condition4 ,! adju/+ may be done by means ( ! tool %[n 9 ,fig4 #adc4 ,?is tool is made f an ord9>y file by gr9d+ (f ! tee? on "o side save = a di/ance ( ab\t #c_/d in* 9 ! middle4 ,! gr9d+ may be done on an em]y :eel4 ,! "p 7a7 is us$ = fil+ ! pole pieces & ?us mak+ ! di/ance betwe5 !m & ! diaphragm great]4 ,! tool has ! advantage ov] an ord9>y file ( p]mitt+ ! poles to be fil$ )\t removal f ! receiv] & )\t groov+ ! diaphragm b$ or ! receiv] case4 ,to less5 ! di/ance betwe5 ! poles & ! diaphragm1 lay ! receiv] b$ d[nw>d on a piece ( f9e em]y pap] & rub ) a circul> sc\r+ motion4 ,if ! em]y pap] is plac$ on a p]fectly flat surface no tr\ble w be exp]i5c$ 9 gr9d+ ! b$ d[n ev5ly4 ,:5 fil+ ! pole pieces rub ) ! same circul> motion s z to gr9d (f all sides ev5ly4 ,te/ f "t to "t by pass+ a /raight edge ov] ! b$ 9 all directions :ile hold+ to ! light & look+ betwe5 ! /raight edge & ! poles4 ,9 ?is mann] ! di/ance sep>at+ ! diaphragm & ! poles may be gaug$ & :e!r or n x is ! same on all sides4 ,be> 9 m9d t if ! diaphragm is ?91 ! attraction ( ! p]man5t magnets w cause x to b5d 9 t[>ds ! poles4 ,9 case y h a pair ( receiv]s built = wireless "w1 :i* appe> to be 9 good condition b d n give _! =m] results1 ! la/ ?+ to d is to tamp] ) ! adju/m5t4 ,! mo/ common cause1 :5 ! tones are impair$1 is dirt or du/ accumulat$ on ! poles or diaphragm & damp+ its vibration4 ,! cap %\ld be c>efully unscrew$ & ! diaphragm exam9$ to see if x is b5t4 ,if s1 replace ) a new "o ( ! same size4 ,remove any dirt or fil+s1 & if ! diaphragm is ru/y clean x by lay+ x on a flat surface & rubb+ x ) a piece ( f9e em]y pap]4 ,!n give x a ?9 coat ( colorless lacqu]4 ,exam9e ! magnets & pole pieces to see if !y h become loos5$ & if s tight5 !m4 ,or ! tr\ble may be t ! p]man5t magnets h lo/ "p ( _! magnetism1 & almo/ any receiv] :i* has be5 9 use = "s l5g? ( "t w be> hav+ its magnets /r5g!n$4 ,if !y are f\nd to be weak !y %\ld be remov$ & remagnetiz$4 ,?is is accompli%$ by w9d+ a coil ( ,no4 #ah ,b4 ,s4 gauge wire ar\nd !m & s5d+ a heavy direct curr5t ?r\gh = a few m9utes4 ,illu/ration3 ,fig4 #add4 ,p>ts ( a ,holtz] ,cabot ,receiv]4 ,9 c>ry+ out any ( ^! sugge/ions rememb] to "w ) "o receiv] at a "t1 keep+ ! o!r = comp>ison1 s t by repeat$ te/s y may tell :e!r or n an improvem5t is be+ made & :5 well en\gh is rea*$1 let x alone4 ,fig4 #add %[s ! con/ruction ( a telephone receiv] manufactur$ by ! ,holtz] ,cabot ,co4 ( ,brookl9e1 ,mass4 ,! p]man5t magnets & bobb9s are m\nt$ 9 a metal cup1 ,b1 :i* supports ! diaphragm1 ,a4 ,! metal cup is enclos$ 9 a h>d rubb] %ell1 ,c1 & fitt$ ) a cap1 ,d4 ,! complete receiv]s are m\nt$ on an adju/able headb& & fitt$ ) pneumatic e> cu%ions :i* make !m set m com=tably & %ut out extrane\s noise4 ,^! receiv]s are w\nd to all resi/ances us$ 9 ! wireless field b1 = ! exp]im5t]1 ^? hav+ a resi/ance ( #ajjj ohms apiece w give ! be/ all ar\nd results4 ,illu/ration3 ,fig4 #ade4 ,holtz] ,cabot ,head ,set4 ,x is v desirable t ! receiv]s %\ld be fitt$ ) a com=table headb& :i* w hold ! telephones 9 close adju/m5t to ! e>s4 ,fig4 #adf %[s ! con/ruction ( su* a b&4 ,illu/ration3 ,fig4 #adf4 ,adju/able ,head ,b&4 ,two brass /raps1 #a in* wide1 #ab in*es long & #a_/af in* ?ick are necess>y4 ,two #a_/h-;in* holes1 mm1 are bor$ 9 !m #c_/af in* f "o end & ! end b5t up at an angle along a l9e #c_/h in* f ! end z %[n by ! draw+4 ,a cov] is made = ! /raps1 by sew+ two /rips ( lea!r #a #a_/d in*es wide & #ab in*es long1 toge!r along _! edges4 ,! cov]s may !n be slipp$ ov] ! /raps4 ,two #a_/af-;in* brass /rips1 #c_/h in* wide & a little long] ?an "o-half ! circumf]5ce ( ! wat*-case receiv] to be fitt$ to ! head b&1 are b5t into /irrups z %[n 9 ! illu/ration by ,y4 ,! ends ( ! /irrups are fitt$ ) two pivots1 ,,pp1 :i* are rivet$ 9 a hole4 ,two holes or recesses are bor$ 9 ! %ell ( ea* receiv]1 on ! sides #ahj degrees ap>t4 ,! pivots1 ,,pp1 fit into ^! holes & =m be>+s 9 :i* ! receiv]s c turn & adju/ !mselves to ! e>s4 ,! /irrup has two small holes1 hh1 bor$ #c_/h in* ap>t at ! top & tapp$ to receive a small screw4 ,! screws pass ?r\gh ! holes1 mm1 & hold ! /irrups at ! end ( _! respective /rap4 ,! lea!r-cov]$ /raps are b\nd toge!r by means ( two clamps :i* p]mit ! head b& to be adju/$ to suit ! we>]4 ,! clamps1 ,c1 are made f #a_/af-;in* brass #c_/h in* wide4 ,_! =m & con/ruction may be be/ und]/ood f ! draw+4 ,a small screw eye is cut 9 half & sold]$ to ! c5t] ( ! upp] side ( ! clamp s t ! receiv] cord may be pass$ ?r\gh ! eyelet1 ,e4 ,! telephone receiv]s %\ld be connect$ 9 s]ies by means ( a flexible telephone cord4 ,,*apt] ,,xvii4 ,,op]ation4 ,! fir/ ess5tial 9 ord] to manage a wireless /ation1 aft] le>n+ ! con/ruction & h&l+ ( ! in/rum5ts1 is to acquire a ?or\gh k ( ! telegraph codes4 ,! two codes 9 use 9 wireless s]vice are ! ,morse & ! ,cont95tal4 ,!y are giv5 bel[4 ,9 "s cases1 ! int5d+ wireless op]ator has _h "s exp]i5ce ) a ,morse s\nd] & !n x is m]ely a matt] ( transition & ( accu/om+ ! e> to a new s\nd4 ,h[ev] x is always be/ to le>n ! ,morse code fir/ z ,cont95tal is m]ely an adaptation 9 :i* no space *>act]s appe>4 ,a beg9n] may le>n to receive mo/ easily by communicat+ ) ano!r p]son to :om x is also new4 ,!y %\ld fir/ memorize all ! lett]s ( ! code & practice transmitt+ be=e comm5c+ any communication4 ,x is a great mi/ake = a beg9n] to />t by writ+ d[n ! dots & da%es z he receives !m on pap]4 ,he %\ld make an ef=t to translate !m & set ! *>act]s & words d[n directly4 ,?is at fir/ w sacrifice spe$ b w make a bett] op]ator & enable "o to become pr(ici5t soon] ?an if he beg9s o!rwise4 ,9 case two complete sets ( wireless app>atus are n conv5i5t1 "o may le>n to read f a buzz] connect$ to a key & a batt]y4 ,! signals may be read directly f ! s\nd ( ! buzz] itself1 b if a pair ( telephone receiv]s are connect$ across ! t]m9als1 a s\nd w be produc$ 9 ! phones simil> to t ( a wireless receptor4 ,9 s5d+1 avoid a %ort1 *oppy or j]ky /yle & h&le ! key ) a light b firm t\*4 ,keep ! dots & da%es firm & ( ! prop] relative l5g?1 z also ! spaces betwe5 lett]s & words4 ,! foll[+ sugge/ions & in/ructions adapt$ f ! ,rules & ,regulations gov]n+ ,naval ,wireless ,telegraph ,/ations may be ( value & s]vice to _m 9 op]at+ _! in/rum5ts4 ,! op]at+ room %\ld be well light$ & free f vibration4 ,! room %\ld h a well insulat$ entrance = ! a]ial & %\ld be fitt$ ) an op]at+ table ab\t two & "o-half feet wide1 n less ?an sev5 feet long & ( a conv5i5t height = work+ ! s5d+ key4 ,! table %\ld be ( dry1 well-season$ wood & ! in/rum5ts %\ld be m\nt$ on ! table at safe sp>k+ di/ances f ea* o!r4 ,! connections %\ld all be z direct z possible & well insulat$4 ,high pot5tial leads %\ld be kept away f l[ pot5tial leads & :]e !y cross x %\ld be at ne>ly "r angles4 ,s5d+ key contacts mu/ be kept clean & flat ) surfaces p>allel to ea* o!r4 ,all slid+ contacts1 especially 9 ! receiv+ tun+ coils1 %\ld be kept clean & bright & free f =eign matt]4 ,a s5d+ set work+ at l[ p[] ) all connections good1 clos$ & op5 circuits 9 resonance1 no sp>k+ f edge ( cond5s]1 j> or plates1 no gl[ f a]ial & no sp>k+ to rigg+1 is utiliz+ its p[] mu* m effici5tly ?an ! same set pu%$ to ! limit ) high resi/ance connections1 sp>k+ at all po9ts & out ( resonance4 ,illu/ration3 ,fig4 #adg4 ,m>coni ,/ation at ,siasconset1 ,mass4 ,x is a good plan = any amateur to keep a note book 9 :i* he c record ! v>i\s di/ances he has be5 able to receive & transmit4 ,he %\ld try m ?an "o circuit & jot d[n ! results4 ,x is !n possible to br+ a /ation up to an effici5cy :i* _c be rea*$ 9 any o!r mann]4 ,,electrical ,,t]ms ,,& ,,def9itions4 ,accumulator3 ,a cell ^: positive & negative electrodes are =m$ or deposit$ by a curr5t fl[+ f a sep>ate s\rce4 ,a]ial3 ,a network or a numb] ( wires insulat$ f surr\nd+ objects & susp5d$ 9 ! air to emit or int]cept electromagnetic waves4 ,alt]nat+ ,curr5t3 ,an electric curr5t1 ( :i* ! direction ( fl[ rev]ses a numb] ( times p] second4 ,amp]e3 ,! quantity ( curr5t :i* w fl[ ?r\gh a resi/ance ( "o ohm "u a pot5tial ( "o volt4 ,! unit ( curr5t4 ,amp]e ,h\r3 ,! quantity ( electricity pass$ :5 fl[+ at ! rate ( "o amp]e = "o h\r4 ,anode3 ,! positive t]m9al ( a brok5 circuit or a s\rce ( electricity4 ,x is ! c>bon ( a cell or ! pole at :i* a curr5t ent]s a solution4 ,capacity3 ,! relative ability ( a conductor to receive & reta9 an electric *>ge4 ,circuit3 ,an unbrok5 conduct+ pa? = an electric curr5t4 ,cond5s]3 ,a device = receiv+ & /or+ up electro/atic en]gy4 ,cycle3 ,! full p]iod ( rev]sal ( an alt]nat+ curr5t4 ,a #fj-;cycle curr5t is "o mak+ #fj complete rev]sals p] second4 ,detector1 ,wireless3 ,an in/rum5t = detect+ oscillations 9 ! a]ial ( a receiv+ /ation4 ,x ei!r v>ies its own int]nal resi/ance or g5]ates a weak int]mitt5t direct curr5t simil> 9 "t & duration ) ! signals emitt$ by ! transmitt+ /ation4 ,dielectric3 ,a non-conductor or insulator4 ,x usually ref]s to ! mat]ial int]pos$ betwe5 ! oppositely *>g$ coat+s ( a cond5s]4 ,direct ,curr5t3 ,a curr5t fl[+ 9 "o direction only4 ,electrode3 ,! t]m9al ( an op5 electric circuit or a conductor c>ry+ a curr5t & imm]s$ 9 an electrolyte4 ,electrolysis3 ,! sep>ation ( a *emical comp\nd into its elem5ts by ! action ( an electric curr5t4 ,electrolyte3 ,a solution :i* w conduct a curr5t ( electricity4 ,electromagnet3 ,a mass ( iron :i* is magnetiz$ by ! passage ( a curr5t ( electricity ?r\gh a coil ( wire w\nd ar\nd ! mass & insulat$ !refrom4 ,f>ad3 ,! unit ( electrical capacity4 ,a cond5s] hav+ a capacity ( "o f>ad w\ld be rais$ to a pot5tial ( "o volt by "o amp]e fl[+ = "o second4 ,field ( ,=ce3 ,! space :i* is "u magnetic /ress 9 ! neighborhood ( a magnet or a wire c>ry+ a curr5t4 ,helix1 ,transmitt+3 ,a coil ( heavy wire :i* furni%es ! inductance = ! clos$ oscillation circuit ( a wireless transmitt] & acts z an auto-trans=m] to raise ! voltage ( ! high frequ5cy curr5ts4 ,h5ry3 ,! unit ( induction4 ,x is ! induction 9 a circuit :5 ! electromotive =ce induc$ 9 ?is circuit is "o volt1 :ile ! induc+ curr5t v>ies at ! rate ( "o amp]e p] second4 ,inductance3 ,! prop]ty ( an electric circuit :]eby l9es ( =ce are develop$ ar\nd x4 ,induction ,coil3 ,an in/rum5t or device consi/+ ( two indep5d5t coils ( wire w\nd ar\nd an iron core1 & :i* by magnetic induction /eps up an int]mitt5t direct curr5t f a l[ to a high voltage4 ,insulator3 ,a non-conductor or a sub/ance imp]vi\s to ! passage ( electricity4 ,key3 ,a device = mak+ & break+ a curr5t into p]iods correspond+ to ! dots & da%es ( ! telegraph code4 ,kil[att3 #a1jjj watts4 ,see watt4 ,leyd5 ,j>3 ,a /atic cond5s] :i* w /ore up /atic electricity & is cyl9drical 9 =m4 ,s-call$ because x 0 orig9at$ 9 ,leyd51 ,holl&4 ,multiple3 ,! t]m express+ ! connection ( sev]al pieces ( electrical app>atus 9 p>allel ) ea* o!r s t ! curr5t is divid$ betwe5 !m4 ,ohm3 ,! unit ( resi/ance4 ,x is arbitr>ily tak5 z ! resi/ance ( a column ( m]cury1 "o squ>e millimet] 9 cross sectional area & #ajf c5timet]s 9 height4 ,p>allel3 ,! same mean+ z multiple4 ,p>allel circuits are ^? :i* />t at a common po9t & end at a common po9t4 ,pol>ization3 ,! collection ( hydrog5 ^u ! positive electrode ( a prim>y cell ) a consequ5t loss ( voltage4 ,pot5tial3 ,voltage or electrical =ce4 ,resi/ance3 ,! quality ( an electrical conductor :]eby x opposes ! passage ( an electric curr5t4 ,! unit ( resi/ance is ! ohm4 ,rheo/at3 ,a v>iable resi/ance to regulate ! /r5g? ( an electric curr5t4 ,s]ies3 ,oppos$ to p>allel or multiple4 ,in/rum5ts 9 s]ies are s connect$ t ! curr5t passes f "o to ! o!r & does n divide4 ,sp>k ,gap3 ,an air gap or op5 space betwe5 two electrodes = ! passage ( a high voltage dis*>ge4 ,/orage ,batt]y3 ,see accumulator4 ,trans=m]3 ,a device = /epp+ up or /epp+ d[n ! voltage ( an alt]nat+ curr5t by means ( magnetic induction4 ,tun+ ,coil3 ,a v>iable inductance = *ang+ ! p]iod ( ! receptor circuit4 ,volt3 ,! unit ( electrical =ce or pot5tial4 ,! electromotive =ce :i*1 if /eadily appli$ to a conductor ^: resi/ance is "o ohm1 w produce a curr5t ( "o amp]e4 ,voltmet]3 ,an in/rum5t = measur+ voltage4 ,watt3 ,unit ( "w4 ,x is ! rate ( "w ( "o amp]e fl[+ "u a pot5tial ( "o volt4 ,sev5 hundr$ & =ty-six watts repres5t "o electrical horsep[]4 ,illu/ration3 99,plate ,,vi4 ,de,forest & ,m>coni ,sy/ems499 ,,*apt] ,,xviii4 ,,! ,,amateur ,,& ,,! ,,wireless ,,law4 ,,:at ,,x ,,is2 ,,h[ ,,to ,,comply2 ,,h[ ,,to ,,secure ,a ,,lic5se4 ,on ,augu/ #ac1 #aiab1 ,congress enact$ a ,wireless ,law to regulate radio communication4 ,! :ole law may be f\nd 9 ! app5dix ( ?is book1 b briefly z f> z ! amateur is conc]n$ x is z foll[s3 ,an amateur may n use transmitt+ app>atus :i* is suffici5tly p[]ful to s5d radio signals across any ( ! b\nd>ies ( ! /ate 9 :i* he is locat$ & :i* c be detect$ by a s5sitive receiv+ set locat$ j beyond ! /ate b\nd>y1 nor c he use app>atus :i* is p[]ful en\gh to int]f]e ) ! reception ( signals by o!rs f beyond ! /ate b\nd>ies unless he has a lic5se4 ,an amateur may receive messages f any:]e at any "t )\t a lic5se provid$ t 8 /ation is n also fitt$ ) transmitt+ app>atus4 ,9 o!r words if ! amateur possesses a receiv+ outfit only :i* is 9 work+ ord] or if he has bo? transmitt] & receptor & ! =m] is n p[]ful en\gh to s5d signals out ( ! /ate 9 :i* he lives1 or to int]f]e ) ! reception ( messages by ano!r :5 ! messages come f beyond ! /ate b\nd>y a lic5se is unnecess>y4 ,?is is ( c\rse some:at unfair = ^? liv+ ne> ! c5t] ( l>ge /ates = !y may op]ate almo/ z !y please ) ord9>y in/rum5ts ) no fe> ( ! signals go+ beyond ! bord]1 :ile ^? liv+ )9 a few miles ( ano!r /ate mu/ secure a lic5se4 ,if an amateur has a lic5se he may transmit messages beyond ! /ate bord]1 b he mu/ n employ a wave l5g? great] ?an #bjj met]s or a p[] input into ! transmitt] ( m ?an #a ,k4,w4 )\t special p]mission4 ,illu/ration3 ,fig4 #adh4 ,exp]im5tal ,amateur ,/ation ( ,w4 ,haddon1 ,brooklyn1 ,n4 ,y4 ,if ! amateur is )9 five nautical miles ( an army or navy /ation equipp$ ) radio app>atus 8 p[] input mu/ n be m ?an #a ,k4,w4 99,comply+ ) ,law499--,aft] a lic5se is secur$1 or r z a matt] ( fact 9 ord] to secure x1 ! wave l5g? mu/ n be great] ?an #bjj met]s4 ,9 ord] to secure su* a wave l5g? ! effective portion ( ! a]ial _c usually be made great] ?an #aae feet 9 consid]ation ( ! am\nt :i* ! lead-91 helix & gr\nd wire add4 ,illu/ration3 ,fig4 #adi4 ,complete ,receiv+ ,outfit ,consi/+ ( ,receiv+ ,trans=m]1 ,detector1 ,fix$ ,cond5s]1 ,load+ ,coil1 ,two ,v>iable ,cond5s]s1 ,pot5tiomet]1 ,batt]y1 ,swit*es1 etc4 ,su* an a]ial w s]ve well = transmitt+ purposes1 b is too %ort = receiv+ v long di/ances4 ,if ! amateur desires to pick up long di/ance messages he mu/ employ two a]ials1 a %ort "o = transmitt+ & a long "o = receiv+4 ,if x is desirable to use ! long a]ial = bo? transmitt+ & receiv+ its wave l5g? may be br\ght d[n to #bjj met]s or "u1 :ile transmitt+ by plac+ a l>ge glass plate cond5s] ( ! prop] capacity 9 s]ies ) ! a]ial4 ,x may be %ort-circuit$ ) a suitable swit* :5 receiv+4 ,! law also says t ! transmitt+ wave mu/ be pure1 & mu/ be %>ply tun$1 :i* means t ! wave mu/ be ( "o l5g? & n1 z is v (t5 ! case1 compos$ ( two or m waves ( diff]5t l5g?s4 ,9 ord] to comply ) ?is re/riction1 ! use ( an oscillation helix or loosely c\pl$ helix is necess>y4 ,a rot>y or qu5*$ gap is also necess>y 9 place ( ! ord9>y sp>k gap4 ,! con/ruction ( all ?ree ( ^! in/rum5ts is describ$ f>!r on4 99,h[ to ,obta9 a ,lic5se499--,9 ord] to obta9 a lic5se s5d to ! ne>e/ ,radio ,inspector2 ,radio ,inspectors are /ation$ at ! ,cu/om ,h\ses at ! foll[+ cities3 ,bo/on1 ,mass42 ,new ,york1 ,n4 ,y42 ,savannah1 ,ga42 ,baltimore1 ,md42 ,clevel&1 ,ohio2 ,*icago1 ,ill42 ,seattle1 ,wa%42 ,new ,orleans1 ,la42 ,san ,francisco1 ,cal42 & obta9 a copy ( ,! ,wireless ,law1 #h-fdab1 ,! ,regulations ,gov]n+ ,radio ,communication1 ,! ,b]l9 ,int]national ,radio-telegraphic ,conv5tion1 & ! necess>y ,application ,=ms4 ,look ov] ! ,wireless ,law1 ! ,regulations & ! ,b]l9 ,conv5tion pamphlet1 !n fill out ,=m #gef4 ,?is is an application = an op]ator's lic5se4 ,illu/ration3 ,fig4 #aej4 ,receiv+ ,outfit ,consi/+ ( ,receiv+ ,trans=m]1 ,fix$ ,cond5s] & ,detector4 ,if ! amateur is n already 9 possession ( a c]tificate ( skill z an op]ator x w be necess>y to f9d out1 f ! comm&ant at ! ne>e/ "o ( ! /ations1 li/$ on page #d ( ! ,regulations z be+ ! places :]e exam9ations are giv51 on :at days ! exam9ations are held4 ,if ! amateur is able to pass ! exam9ation1 an op]ator's lic5se w be issu$4 ,!n fill out ,=m #geg & =w>d x to ! ,radio ,inspector4 ,if he ?9ks y\r /ation con=ms to ! regulations )\t inspection ! lic5se w be issu$2 if n1 ! lic5se w be issu$ aft] inspection4 ,!re are no fees to pay 9 connection ) secur+ any ( ! lic5ses4 ,,app>atus ,,requir$ ,,9 ,,_m ,,in/ances ,,9 ,,ord] ,,to ,,comply ,,) ,,! ,,wireless ,,law4 99,,oscillation ,,helix99 ,! oscillation helix has almo/ become a necessity 9 ord] to comply ) ! regulations ( ! ,wireless ,law reg>d+ wave =m1 except 9 ^? /ations :]e a qu5*$ gap is us$4 ,illu/ration3 ,fig4 #aea4 ,amco ,oscillation ,helix4 ,! wave emitt$ by _m /ations is n pure4 ,x is compos$ usually ( two or ?ree sep>ate waves ( diff]5t l5g?s in/ead ( all ! en]gy be+ conf9$ to oscillations ( "o p]iod4 ,x is possible to tune su* a wave 9 two or m places or humps1 z !y are call$1 on ! tun+ coil4 ,x is obvi\s t a wave possess+ su* humps _c be closely tun$ & is liable to int]f]e ) ! signals ( ano!r /ation4 ,?is is "o ( ! pr9cipal causes ( int]f]5ce4 ,! reason = ?is ph5om5on is simple4 ,! action ( a transmitt] is to fir/ *>ge a cond5s]4 ,:5 ! pot5tial ( ! cond5s] rises to suffici5t value x dis*>ges across ! sp>k gap & sets up oscillations 9 ! clos$ circuit4 ,^! oscillations imm$iately induce oscillations 9 ! op5 circuit or a]ial sy/em & "p ( ! en]gy passes (f into ! e!r z electro-magnetic waves4 ,h[ev]1 ! oscillations 9 ! a]ial sy/em d n imm$iately die away aft] ! oscillations 9 ! clos$ circuit cease dur+ ! int]im until ! next cond5s] dis*>ge1 b cont9ue to surge & react ^u ! dos$ circuit to suffici5t ext5t to induce !re9 curr5ts :i* surge back & =? long aft] ! curr5t f ! cond5s] dis*>ge has di$ away4 ,we might call ! oscillations due to ! cond5s] dis*>ge prim>y oscillations & ^? induc$ 9 ! a]ial !reby second>y oscillations4 ,^? :i* are !n set up 9 ! clos$ circuit by ! reaction ( ! second>y curr5ts are t]ti>y4 ,?is ?ird tra9 ( oscillations p]si/ aft] ! second>y curr5ts h di$ away1 & induce ano!r set ( oscillations 9 ! a]ial :i* s5d out a second set ( electromagnetic waves diff]+ 9 l5g? f ! fir/4 ,! oscillations :i* take place aft] ! initial surge 9 ! clos$ & op5 circuits are naturally some:at weak4 ,by us+ an oscillation helix 9 :i* ! prim>y & second>y are sep>at$ f ea* o!r x is possible to elim9ate ! ?ird & f\r? tra9s ( oscillations & all o!rs hav+ a t5d5cy to foll[1 by plac+ ! circuits ap>t s t ! weak oscillations are n /rong en\gh99 to react across ! int]v5+ space4 ,! imm$iate oscillations set up by ! cond5s] dis*>ge are /rong en\gh to act across ! space & set up p[]ful oscillations 9 ! a]ial4 ,illu/ration3 ,fig4 #aeb4 ,details ( ,oscillation ,helix ,con/ruction4 ,a hot wire ammet] plac$ 9 ! a]ial circuit ( a transmitt] employ+ an oscillation trans=m] w n indicate z mu* curr5t z if plac$ 9 ! same position 9 a circuit us+ an ord9>y helix2 b 9 spite ( ! fact1 a transmitt] us+ an oscillation helix w s5d f>!r because ! en]gy is conc5trat$ 9 waves ( "o l5g?4 ,! con/ruction ( "o type ( oscillation helix has already be5 outl9$ on page #ib4 ,! =m %[n 9 ,fig4 #aeb has no special advantages ov] ! o!r b is pref]r$ by _m exp]im5t]s4 ,x is ( ! pancake type1 s-call$ because ( ! flat =m ( ! w9d+s :i* are made 9 ! %ape ( a spiral ( brass ribbon set 9 a slott$ frame4 ,! dim5sions ( ! helix are cle>ly app>5t f ! draw+4 ,! prim>y is compos$ ( sev5 turns ( brass ribbon #a_/b in* wide & #a_/af in* ?ick4 ,! second>y %\ld h f #aj to #ae turns ( ribbon #c_/h x #a_/af4 ,! coils may be slid back & =? on ! brass rod s t ! di/ance betwe5 !m is v>iable4 ,connection is made to ! coils by means ( suitable clips4 ,a clip simil> to t %[n on page #ib1 b made to snap on a flat ribbon in/ead ( a r\nd wire1 w s]ve ! purpose4 99,,qu5*$ ,,sp>k ,,gap499 ,a qu5*$ gap is made up ( a numb] ( brass or copp] disks accurately turn$ to a true surface & sep>at$ by mica or rubb] r+s ab\t 4#ja in* ?ick4 ,! sp>k dis*>ge takes place 9 ! air-tight space at ! c5t] ( ! disks1 inside ( ! mica r+s4 ,! qu5*$ gap has sev]al advantages ov] o!r =ms4 ,x is practically noiseless & ! nuisance ( a cra%+ dis*>ge may be avoid$ by its use4 ,! l>ge surface (f]$ to ! sp>k by ! disks cools ! sp>k & quickly /ops ! oscillations 9 ! clos$ circuit1 & !reby leaves ! op5 circuit & a]ial sy/em free to vibrate 9 its own p]iod & !re=e radiates pure waves4 ,by pure wave a wave ( "o l5g? is meant4 ,a qu5*$ gap _c be us$ on a set ( ov] #a ,k4,w4 p[] )\t artificial cool+ by an air bla/4 ,illu/ration3 ,fig4 #aec4 ,qu5*$ ,gap4 ,illu/ration3 ,fig4 #aed4 ,qu5*$ ,gap4 ,fig4 #aed %[s an effici5t =m ( qu5*$ gap = use 9 /ations up to #a ,k4,w4 9 p[]4 ,! disks are %[n 9 detail 9 ,fig4 #aee4 ,!y are ca/ out ( copp] & !n turn$ p]fectly true & smoo? 9 a la!4 ,aft] surfac+1 ! dis*>ge surface %\ld be heavily silv] plat$ & buff$ smoo?4 ,illu/ration3 ,fig4 #aee4 ,details ( ,disk & ,r+4 ,! disks are pil$ on a m>ble base ) a mica r+ betwe5 ea*4 ,!y are clamp$ d[n by a /rong set screw m\nt$ on a heavy brass yoke4 ,en\gh pressure %\ld be br\ght to be> to =ce ! plates tightly toge!r & make !m air tight4 ,illu/ration3 ,fig4 #aef4 ,explanatory ,draw+ ( ,qu5*$ ,gap4 ,! numb] ( disks requir$ is gov]n$ by ! voltage ( ! *>g+ cond5s]4 ,g5]ally speak+ x is "o section ( 4#ja-;in* gap = ea* ?\s& volts deliv]$ by ! second>y ( ! trans=m]4 ,x is v important to secure j ! prop] numb] ( disks4 ,if prop]ly adju/$1 ! qu5*$ gap w give "o dis*>ge = ea* alt]nation ( ! curr5t & produce a musical tone4 ,! qu5*$ gap is plac$ 9 ! same position 9 ! transmitt+ circuit z any o!r =m ( gap4 99,,rot>y ,,gaps499 ,rot>y gaps are divid$ into two g5]al classes1 ! syn*ron\s gap & ! non-syn*ron\s gap4 ,! =m] usually consi/s ( "o or m /ation>y electrodes & a rotat+ memb] made l a /> :eel ) project+ spokes4 ,?is rot>y memb] is atta*$ directly to ! %aft ( ! alt]nator or motor g5]ator & arrang$ s t a spoke always comes opposite a /ation>y memb] at ! exact mom5t t ! maximum ( pot5tial is obta9$ 9 ! cond5s]4 ,su* an arrangem5t p]mits "o dis*>ge = ea* alt]nation ( ! curr5t & produces a pure musical note easily di/+ui%$ 9 ! telephone receiv]s at a di/ant /ation4 ,9 ! non-syn*ron\s rot>y gap ! :eel is driv5 at a high rate ( spe$ )\t any reg>d to syn*ronism ) ! alt]nations ( ! curr5t4 ,! rot>y gap %[n 9 ,fig4 #aeg is ( ! non-syn*ron\s type4 ,illu/ration3 ,fig4 #aeg4 ,amco ,rot>y ,gap4 ,! rotat+ memb] is ca/ f an alloy ( equal p>ts ( z9c & alum9um4 ,x is necess>y to fir/ make a wood5 patt]n f :i* ! ca/+ may be made4 ,! details ( ! :eel are %[n 9 ,fig4 #aeh4 ,! ca/+ mu/ be plac$ 9 a la! *uck & turn$ true4 ,x is m\nt$ on a h>d rubb] disk #b #g_/h in*es 9 diamet] & #a_/d ( an in* ?ick4 ,! disk s]ves to insulate ! revolv+ electrodes f ! motor %aft4 ,! rotor is m\nt$ ^u ! %aft by means ( a small brass bu%+ :i* passes ?r\gh ! c5t] ( ! disk4 ,illu/ration3 ,fig4 #aeh4 ,details ( ,revolv+ ,p>ts ( ,rot>y ,gap4 ,! motor mu/ be well built & capable ( runn+ at high spe$4 ,a ,juno motor w be f\nd v satisfactory4 ,:5 runn+ free its spe$ is ab\t #dejj r4p4m4 ,) ! rotor 9 place ! spe$ is ab\t #cfjj r4p4m4 ,! motor %\ld be m\nt$ on a heavy m>ble base capable ( absorb+ any little vibration t ! gap may be subject to :5 runn+ at high spe$4 ,! /ation>y electrodes are made 9 ! same mann] z ^? = an ord9>y gap & consi/s ( two flang$ z9c electrodes m\nt$ ^u ?read$ brass rods support$ by two hexagonal /&>ds4 ,! axis ( ! electrodes %\ld be ! same height above ! base z t ( ! motor %aft4 ,! rotor %\ld be c>efully balanc$ s t x is practically free f vibration by bor+ small holes 9 ! back face s z to make ! weight on opposite sides equal4 ,illu/ration3 ,fig4 #aei4 ,details ( ,rot>y ,gap4 ,! motor may be driv5 by a batt]y or f ! same s\rce t supplies ! trans=m]1 9 s]ies ) two or ?ree suitable lamps4 ,a motor w\nd to run directly f ! #aaj-volt l9e or a high] pot5tial mu/ h its fields w\nd ) v f9e wire & is apt to give tr\ble ?r\gh burn-outs1 due to kick back4 ,:5 ! motor is op]at$ on batt]ies or is w\nd = runn+ 9 s]ies ) a lamp ! dang] is less5$4 ,a rot>y gap is plac$ 9 ! transmitt+ circuit 9 ! same position z any o!r gap4 ,its use w result 9 a wond]ful increase 9 ! transmitt+ range ( almo/ any /ation1 = n only w ! am\nt ( en]gy pass+ ?r\gh ! a]ial be rais$1 b ! cle> musical tone giv5 (f is m pla9ly di/+ui%able at a great] di/ance 9 ! receiv+ /ation ?an a sp>k ( ! ord9>y sort4 99,,kick ,,back499 ,! oscillations tak+ place 9 ! clos$ circuit & a]ial sy/em ( a wireless transmitt] cont9ue to surge aft] ! curr5t 9 ! cond5s] has dropp$ bel[ a c]ta9 value1 & react ^u ! prim>y w9d+ ( ! coil or trans=m] by induction & produce high voltage1 high frequ5cy curr5ts t]m$ kick back1 9 wireless telegraph p>lance4 ,kick back1 :]ev] x exi/s to an appreciable ext5t1 is liable to damage insulation & cause possible burn-outs4 ,! kick-back prev5t]s illu/rat$ 9 ! accompany+ diagrams w be f\nd an effici5t me?od ( avoid+ ?is dang]4 ,illu/ration3 ,fig4 #afj4 ,me?ods ( ,prev5t+ ,kick ,back4 ,! fir/ me?od %[s an ord9>y press$ telephone cond5s] ( ab\t two micr(>ads capacity connect$ directly across ! ,a4 ,c4 ma9s ne> ! trans=m] t]m9als1 9 s]ies ) two #f-;amp]e fuses4 ,! cond5s] is %unt$ by a small sp>k gap made ( ne$le po9ts ) a v small space1 ab\t 4#jje ( an in*1 betwe5 !m4 ,! second me?od is an elaboration ( ! fir/ & %[s two sets ( cond5s]s 9 s]ies ) fuses & bridg$ by sp>k gaps ) a gr\nd ?r\gh a ?ird cond5s] connect$ betwe54 ,?is second me?od is ! be/ & is (t5 us$ to prev5t delicate in/rum5ts1 su* z a voltmet]1 f ! effects ( kick back4 ,a prop] kick-back prev5t] is "p ( ! ,fire ,insurance ,und]writ]s requirem5ts = a wireless telegraph /ation4 ,receiv+ ,app>atus4 99,,! ,,v>iomet]499 ,a v>iomet] is a tun+ device 9 :i* two coils ( wire are plac$ 9 s]ies & connect$ s t ! turns c be made to oppose "o ano!r4 ,"o coil is movable & by turn+ x ! curr5ts fl[+ ?r\gh ! adjac5t coils oppose ea* o!r & decrease ! self-induction ( ! :ole & consequ5tly ! p]iod ( ! circuit4 ,illu/ration3 ,fig4 #afa4 ,v>iomet]4 ,! accompany+ illu/ration %[s ! con/ructive details ( an effici5t =m ( v>iomet]4 ,! coils are w\nd ar\nd two c>dbo>d cyl9d]s4 ,"o cyl9d] is #f in*es 9 diamet] & ! o!r #e in*es4 ,bo? are #b in*es long4 ,! l>ge cyl9d] is w\nd ) tw5ty-five turns ( ,no4 #bb ,b4 ,s4 gauge s+le silk cov]$ wire w\nd 9 two sections s z to leave a space #c_/h in* wide 9 ! c5t]4 ,! small cyl9d] is w\nd 9 ! same mann] ) ! same size ( wire b conta9s ?irty turns s z to make ! l5g? ( wire 9 ea* ( ! coils practically equal4 ,! space 9 ! c5t] ( ea* ( ! coils all[s a support+ rod to pass ?r\gh )\t int]f]+ ) ! wire4 ,! %aft is a piece ( #e_/af brass rod ab\t #g #a_/b in*es long4 ,! upp] end is provid$ ) a knob & a po9t]4 ,! l>ge coil is m\nt$ on ! "u side ( a wood5 cov] made to fit a conta9+ case ( ! prop] size to receive ! v>iomet] & ( a /yle simil> to t ord9>ily us$ to enclose a v>iable cond5s]4 ,! %aft passes ?r\gh ! l>g] coil1 at two po9ts diametrically opposite1 b %\ld n fit tightly4 ,x also passes ?r\gh ! small] coil b is fa/5$ to ! latt] by means ( a cross b> s t :5 ! knob is turn$ ! coil w revolve also4 ,! coils are connect$ by means ( a piece ( braid$ wire or flexible conductor1 long en\gh s z n to int]f]e ) ! movem5t ( ! inn] coil4 ,! outside t]m9als ( ! coils t]m9ate 9 b9d+ po/s m\nt$ on ! top ( ! case4 ,:5 mak+ a v>iomet] be c>eful n to employ any iron or /eel 9 its con/ruction1 n ev5 iron screws4 ,! v>iomet] is plac$ 9 ! receiv+ circuit by connect+ x 9 s]ies ) ! a]ial be=e x rea*es ! tun+ coil or loose c\pl]4 99,,new ,,cry/al ,,detectors499 99,silicon ,detector499--,! silicon detector is always int]e/+ because x 0 "o ( ! fir/ m9]al rectifi]s to come into ext5d$ use4 ,! photograph %[n bel[ illu/rates "o ( ! late/ =ms ( ! silicon detector4 ,illu/ration3 ,fig4 #afb4 ,silicon ,detector4 ,! l>ge cup support$ by ! left-h& /&>d contacts sev]al pieces ( fus$ silicon emb$d$ 9 fusible alloy4 ,! "r-h& /&>d supports a movable (fset cup ! same z t us$ on ! ,p]ikon type ( ,detector4 ,a small piece ( ars5ic is m\nt$ 9 ?is cup & may be br\ght to be> aga9/ any portion ( any ( ! silicon cry/als4 99,pyron ,detector499--,! ,pyron detector is n new1 b ! photograph %[s a v simple & effici5t =m 9 :i* a f9e wire is br\ght to be> aga9/ a cry/al ( iron pyrites m\nt$ 9 a small cup4 ,illu/ration3 ,fig4 #afc4 ,pyron ,detector4 99,gal5a ,detector499--,al?\gh gal5a is nam$ 9 ! li/ ( s5sitive m9]als on page #acb x has come into su* ext5sive use z a detector s9ce ! fir/ edition ( ?is book to be wor?y ( special att5tion4 ,gal5a detectors are (t5 spok5 ( z cat-:isk] detectors because ( ! long f9e wire us$ to secure a delicate contact ) ! m9]al4 ,! m9]al is usually plac$ 9 a cup & held 9 position by imb$d+ 9 fusible alloy or clamp$ ) a set screw4 ,! be/ surface ( ! m9]al %\ld be select$ by te/+ previ\s to imb$d+ x 9 ! cup4 ,contact is made ) ! surface ( ! m9]al by means ( a piece ( ,no4 #cj phosphor bronze wire m\nt$ on ! end ( a %ort brass rod fitt$ ) an adju/+ screw s t by turn+ or twi/+ ! surface ( ! m9]al may be se>*$ & ! t5sion v>i$4 ,illu/ration3 ,fig4 #afd4 ,gal5a ,detector4 ,su* an arrangem5t is illu/rat$ 9 ,fig4 #afd4 ,! base is a h>d rubb] block #c #c_/d x #a #c_/d x #a_/b4 ,! b9d+ po/s are ( ! type commonly us$ on electrical in/rum5ts4 ,"o ( ! po/s is pivot$ by plac+ a spr+ wa%] "u ! head ( ! screw :i* holds ! po/ to ! base4 ,a %ort piece ( brass rod fitt$ ) a h>d rubb] knob passes ?r\gh ! wire hole 9 ! po/4 ,a piece ( ,no4 #cj phosphor bronze wire is sold]$ to ! end ( ! rod4 ,by twi/+ ! po/ & slid+ ! rod any portion ( ! m9]al surface may be select$4 ,twi/+ ! rod v>ies ! t5sion ( ! contact4 ,! gal5a detector is connect$ 9 ! receiv+ circuit 9 ! same mann] z o!r detectors ( ! m9]al type4 99,,! ,,audion499 99,! ,audion99--is f9d+ favor 9 _m amateur wireless /ations1 because ( its almo/ entire lack ( adju/m5t & ( ! l\d cle> signals :i* x gives ev5 :5 us$ = long di/ance "w4 ,! illu/ration %[s ! late/ =m ( audion1 ! plate & ! grid bo? be+ on ! same side ( ! filam5t4 ,! filam5t ( an audion is usually light$ by means ( a six-volt /orage batt]y4 ,a small batt]y rheo/at plac$ 9 s]ies ) ! batt]y s]ves to regulate ! am\nt ( curr5t fl[+ ?r\gh ! filam5t4 ,only "o filam5t is us$ at a "t1 ! o!r be+ sav$ z a res]ve 9 case ! fir/ burns out4 ,illu/ration3 ,fig4 #afe4 ,audion4 ,! high] voltage necess>y to op]ate an audion is suppli$ by a batt]y consi/+ ( fifte5 fla%light batt]ies1 ea* fla%light batt]y be+ compos$ ( ?ree sep>ate cells4 ,! batt]ies are connect$ to an eight-po9t swit* s t ?r[+ ! swit* on ! fir/ po9t w connect five sets ( batt]ies4 ,! second po9t places five m 9 circuit & ea* additional po9t "o set only4 ,x is also a good plan to connect a f\r-po9t swit* & ?ree sep>ate cells ( batt]y 9 s]ies ) ! eight-po9t swit* s t !y may be add$ to ! circuit "o at a "t & ! pot5tial v>i$ m closely ?an ! /eps on ! eight-po9t swit* p]mit4 ,! maximum voltage ( su* a batt]y is approximately #ef volts4 ,! diagram 9 ,fig4 #aff %[s exactly h[ an audion is connect$4 ,! wires ,a & ,b are ! t]m9als lead+ to ! tun+ coil or loose c\pl]4 ,x is n necess>y t ! telephone receiv]s us$ ) an audion be w\nd to a high resi/ance 9 ord] to secure good results4 ,illu/ration3 ,fig4 #aff4 ,audion ,circuit4 ,! audion is plac$ 9 op]ation by turn+ ! rheo/at until ! filam5t lights brightly4 ,!n adju/ ! voltage ( ! high pot5tial batt]y until ! signals are cle>e/4 ,if ! voltage is too high ! audion w become fill$ ) a blui% light & ! voltage %\ld be imm$iately r$uc$4 ,! signals w be l\de/ :5 ! filam5t is brilliantly light$4 ,no m curr5t %\ld be pass$ ?r\gh ! filam5t ?an is necess>y to r5d] ! signals pla91 = if =c$ its life w be limit$ to only a few h\rs4 ,illu/ration3 ,fig4 #afg4 ,rot>y ,v>iable ,cond5s]4 99,,app5dix499 ,,public ,no4 #bfd4 ,s4 #fdab4 ,an ,act to ,regulate ,radio ,communication4 ,be x enact$ by ! ,s5ate & ,h\se ( ,repres5tatives ( ! ,unit$ ,/ates ( ,am]ica 9 ,congress assembl$4 ,t a p]son1 company1 or corporation )9 ! jurisdiction ( ! ,unit$ ,/ates %all n use or op]ate any app>atus = radio communication z a means ( comm]cial int]c\rse among ! sev]al ,/ates1 or ) =eign nations1 or ^u any vessel ( ! ,unit$ ,/ates engag$ 9 int]/ate or =eign comm]ce1 or = ! transmission ( radiograms or signals ! effect ( :i* ext5ds beyond ! jurisdiction ( ! ,/ate or ,t]ritory 9 :i* ! same are made1 or :]e int]f]5ce w\ld be caus$ !reby ) ! receipt ( messages or signals f beyond ! jurisdiction ( ! said ,/ate or ,t]ritory1 except "u & 9 accordance ) a lic5se1 revocable = cause1 9 t behalf grant$ by ! ,secret>y ( ,comm]ce & ,labor ^u application !re=2 b no?+ 9 ?is ,act %all be con/ru$ to apply to ! transmission & ex*ange ( radiograms or signals betwe5 po9ts situat$ 9 ! same ,/ate3 ,provid$1 ,t ! effect !re( %all n ext5d beyond ! jurisdiction ( ! said ,/ate or int]f]e ) ! reception ( radiograms or signals f beyond said jurisdiction2 & a lic5se %all n be requir$ = ! transmission or ex*ange ( radiograms or signals by or on behalf ( ! ,gov]nm5t ( ! ,unit$ ,/ates1 b e ,gov]nm5t /ation on l& or sea %all h special call lett]s designat$ & publi%$ 9 ! li/ ( radio /ations ( ! ,unit$ ,/ates by ! ,dep>tm5t ( ,comm]ce & ,labor4 ,any p]son1 company1 or corporation t %all use or op]ate any app>atus = radio communication 9 violation ( ?is section1 or kn[+ly aid or abet ano!r p]son1 company1 or corporation 9 s do+1 %all be deem$ guilty ( a misdemeanor1 & on conviction !re( %all be puni%$ by a f9e n exce$+ five hundr$ doll>s1 & ! app>atus or device s unlawfully us$ & op]at$ may be adjudg$ =feit$ to ! ,unit$ ,/ates4 ,,sec4 #b4 ,t e su* lic5se %all be 9 su* =m z ! ,secret>y ( ,comm]ce & ,labor %all det]m9e & %all conta9 ! re/rictions1 pursuant to ?is ,act1 on & subject to :i* ! lic5se is grant$2 t e su* lic5se %all be issu$ only to citiz5s ( ! ,unit$ ,/ates or ,porto ,rico or to a company incorporat$ "u ! laws ( "s ,/ate or ,t]ritory or ( ! ,unit$ ,/ates or ,porto ,rico1 & %all specify ! own]%ip & location ( ! /ation 9 :i* said app>atus %all be us$ & o!r p>ticul>s = its id5tification & to enable its range to be e/imat$2 %all /ate ! purpose ( ! /ation1 &1 9 case ( a /ation 9 actual op]ation at ! date ( passage ( ?is ,act1 %all conta9 ! /atem5t t satisfactory pro( has be5 furni%$ t x 0 actually op]at+ on ! above-m5tion$ date2 %all /ate ! wave l5g? or ! wave l5g?s au?oriz$ = use by ! /ation = ! prev5tion ( int]f]5ce & ! h\rs = :i* ! /ation is lic5s$ = "w2 & %all n be con/ru$ to au?orize ! use ( any app>atus = radio communication 9 any o!r /ation ?an t specifi$4 ,e su* lic5se %all be subject to ! regulations conta9$ h]e91 & su* regulations z may be e/abli%$ f "t to "t by au?ority ( ?is ,act or subsequ5t ,acts & treaties ( ! ,unit$ ,/ates4 ,e su* lic5se %all provide t ! ,presid5t ( ! ,unit$ ,/ates 9 "t ( w> or public p]il or disa/] may cause ! clos+ ( any /ation = radio communication & ! removal !refrom ( all radio app>atus1 or may au?orize ! use or control ( any su* /ation or app>atus by any dep>tm5t ( ! ,gov]nm5t1 ^u j comp5sation to ! own]s4 ,,sec4 #c4 ,t e su* app>atus %all at all times :ile 9 use & op]ation z a=esaid be 9 *>ge or "u ! sup]vision ( a p]son or p]sons lic5s$ = t purpose by ! ,secret>y ( ,comm]ce & ,labor4 ,e p]son s lic5s$ :o 9 ! op]ation ( any radio app>atus %all fail to obs]ve & obey regulations conta9$ 9 or made pursuant to ?is ,act or subsequ5t ,acts or treaties ( ! ,unit$ ,/ates1 or any "o ( !m1 or :o %all fail to en=ce ob$i5ce !reto by an unlic5s$ p]son :ile s]v+ "u 8 sup]vision1 9 addition to ! puni%m5ts & p5alties h]e9 prescrib$1 may suff] ! susp5sion ( ! said lic5se = a p]iod to be fix$ by ! ,secret>y ( ,comm]ce & ,labor n exce$+ "o ye>4 ,x %all be unlawful to employ any unlic5s$ p]son or = any unlic5s$ p]son to s]ve 9 *>ge or 9 sup]vision ( ! use & op]ation ( su* app>atus1 & any p]son violat+ ?is provision %all be guilty ( a misdemeanor1 & on conviction !re( %all be puni%$ by a f9e ( n m ?an "o hundr$ doll>s or imprisonm5t = n m ?an two mon?s1 or bo?1 9 ! discretion ( ! c\rt1 = ea* & e su* (f5se3 ,provid$1 ,t 9 case ( em]g5cy ! ,secret>y ( ,comm]ce & ,labor may au?orize a collector ( cu/oms to issue a tempor>y p]mit1 9 lieu ( a lic5se1 to ! op]ator on a vessel subject to ! radio %ip ,act ( ,june tw5ty-f\r?1 n9ete5 hundr$ & t54 ,,sec4 #d4 ,t = ! purpose ( prev5t+ or m9imiz+ int]f]5ce ) communication betwe5 /ations 9 :i* su* app>atus is op]at$1 to facilitate radio communication1 & to fur!r ! prompt receipt ( di/ress signals1 said private & comm]cial /ations %all be subject to ! regulations ( ?is section4 ,^! regulations %all be en=c$ by ! ,secret>y ( ,comm]ce & ,labor ?r\gh ! collectors ( cu/oms & o!r (fic]s ( ! ,gov]nm5t z o!r regulations h]e9 provid$ =4 ,! ,secret>y ( ,comm]ce & ,labor may1 9 8 discretion1 waive ! provisions ( any or all ( ^! regulations :5 no int]f]5ce ( ! "* above m5tion$ c ensue4 ,! ,secret>y ( ,comm]ce & ,labor may grant special tempor>y lic5ses to /ations actually engag$ 9 conduct+ exp]im5ts = ! developm5t ( ! sci5ce ( radio communication1 or ! app>atus p]ta9+ !reto1 to c>ry on special te/s1 us+ any am\nt ( p[] or any wave l5g?s1 at su* h\rs & "u su* conditions z w insure ! lea/ int]f]5ce ) ! s5d+ or receipt ( comm]cial or ,gov]nm5t radiograms1 ( di/ress signals & radiograms1 or ) ! "w ( o!r /ations4 ,9 ^! regulations ! naval & milit>y /ations %all be und]/ood to be /ations on l&4 ,,regulations4 ,,normal ,,wave ,,l5g?4 ,fir/4 ,e /ation %all be requir$ to designate c]ta9 def9ite wave l5g? z ! normal s5d+ & receiv+ wave l5g? ( ! /ation4 ,?is wave l5g? %all n exce$ six hundr$ met]s or x %all exce$ "o ?\s& six hundr$ met]s4 ,e coa/al /ation op5 to g5]al public s]vice %all at all times be ready to receive messages ( su* wave l5g?s z are requir$ by ! ,b]l9 conv5tion4 ,e %ip /ation1 except z h]e9aft] provid$1 & e coa/ /ation op5 to g5]al public s]vice %all be prep>$ to use two s5d+ wave l5g?s1 "o ( ?ree hundr$ met]s & "o ( six hundr$ met]s1 z requir$ by ! int]national conv5tion 9 =ce3 ,provid$1 ,t ! ,secret>y ( ,comm]ce & ,labor may1 9 8 discretion1 *ange ! limit ( wave l5g? res]vation made by regulations fir/ & second to accord ) any int]national agreem5t to :i* ! ,unit$ ,/ates is a p>ty4 ,,o!r ,,wave ,,l5g?s4 ,second4 ,9 addition to ! normal s5d+ wave l5g? all /ations1 except z provid$ h]e9aft] 9 ^! regulations1 may use o!r s5d+ wave l5g?s3 ,provid$1 ,t !y d n exce$ six hundr$ met]s or t !y d exce$ "o ?\s& six hundr$ met]s3 ,provid$ fur!r1 ,t ! "* ( ! waves emitt$ con=ms to ! requirem5ts ( regulations ?ird & f\r? foll[+4 ,,use ,,( ,a ,,pure ,,wave ,?ird4 ,at all /ations if ! s5d+ app>atus1 to be ref]r$ to h]e9aft] z ! transmitt]1 is ( su* a "* t ! en]gy is radiat$ 9 two or m wave l5g?s1 m or less %>ply def9$1 z indicat$ by a s5sitive wave met]1 ! en]gy 9 no "o ( ! less] waves %all exce$ t5 p] c5tum ( t 9 ! greate/4 ,,use ,,( ,a ,,%>p ,,wave4 ,f\r?4 ,at all /ations ! log>i?mic decrem5t p] complete oscillation 9 ! wave tra9s emitt$ by ! transmitt] %all n exce$ two-t5?s1 except :5 s5d+ di/ress signals or signals & messages relat+ !reto4 ,,use ,,( ,,/&>d ,,di/ress ,,wave4 ,fif?4 ,e /ation on %ipbo>d %all be prep>$ to s5d di/ress calls on ! normal wave l5g? designat$ by ! int]national conv5tion 9 =ce1 except on vessels ( small tonnage unable to h plants insur+ t wave l5g?4 ,,signal ,,( ,,di/ress4 ,six?4 ,! di/ress call us$ %all be ! int]national signal ( di/ress3 dot dot dot1 da% da% da%1 dot dot dot4 ,,use ,,( ,,broad ,,int]f]+ ,,wave ,,= ,,di/ress ,,signals4 ,sev5?4 ,:5 s5d+ di/ress signals1 ! transmitt] ( a /ation on %ipbo>d may be tun$ 9 su* a mann] z to create a maximum ( int]f]5ce ) a maximum ( radiation4 ,,di/ance ,,requirem5t ,,= ,,di/ress ,,signals4 ,eigh?4 ,e /ation on %ipbo>d1 :]ev] practicable1 %all be prep>$ to s5d di/ress signals ( ! "* specifi$ 9 regulations fif? & six? ) suffici5t p[] to enable !m to be receiv$ by day ov] sea a di/ance ( "o hundr$ nautical miles by a %ipbo>d /ation equipp$ ) app>atus = bo? s5d+ & receiv+ equal 9 all ess5tial p>ticul>s to t ( ! /ation fir/ m5tion$4 ,,= ,,di/ress ,,signals4 ,n9?4 ,all /ations are requir$ to give absolute priority to signals & radiograms relat+ to %ips 9 di/ress2 to cease all s5d+ on he>+ a di/ress signal2 &1 except :5 engag$ 9 answ]+ or aid+ ! %ip 9 di/ress1 to refra9 f s5d+ until all signals & radiograms relat+ !reto are complet$4 ,,r$uc$ ,,p[] ,,= ,,%ips ,,ne> ,a ,,gov]nm5t ,,/ation4 ,t5?4 ,no /ation on %ipbo>d1 :5 )9 fifte5 nautical miles ( a naval or milit>y /ation1 %all use a trans=m] input exce$+ "o kil[att1 nor1 :5 )9 five nautical miles ( su* a /ation1 a trans=m] input exce$+ "o-half kil[att1 except = s5d+ signals ( di/ress1 or signals or radiograms relat+ !reto4 ,,int]communication4 ,elev5?4 ,ea* %ore /ation op5 to g5]al public s]vice betwe5 ! co/ & vessels at sea %all be b\nd to ex*ange radiograms ) any simil> %ore /ation & ) any %ip /ation )\t di/9ction ( ! radio sy/ems adopt$ by su* /ations1 respectively1 & ea* /ation on %ipbo>d %all be b\nd to ex*ange radiograms ) any o!r /ation on %ipbo>d )\t di/9ction ( ! radio sy/ems adopt$ by ea* /ation respectively4 ,x %all be ! duty ( ea* su* %ore /ation1 dur+ ! h\rs x is 9 op]ation1 to li/5 9 at int]vals ( n less ?an fifte5 m9utes & = a p]iod n less ?an two m9utes1 ) ! receiv] tun$ to receive messages ( ?ree hundr$ met] wave l5g?s4 ,,division ,,( ,,"t4 ,twelf?4 ,at important seaports & at all o!r places :]e naval or milit>y & private or comm]cial %ore /ations op]ate 9 su* close proximity t int]f]5ce ) ! "w ( naval & milit>y /ations c n be avoid$ by ! en=cem5t ( ! regulations conta9$ 9 ! =ego+ regulations conc]n+ wave l5g?s & "* ( signals emitt$1 su* private or comm]cial %ore /ations z d int]f]e ) ! reception ( signals by ! naval & milit>y /ations conc]n$ %all n use _! transmitt]s dur+ ! fir/ fifte5 m9utes ( ea* h\r1 local /&>d "t4 ,! ,secret>y ( ,comm]ce & ,labor may1 on ! recomm5dation ( ! dep>tm5t conc]n$1 designate ! /ation or /ations :i* may be requir$ to obs]ve ?is division ( "t4 ,,gov]nm5t ,,/ations ,,to ,,obs]ve ,,division ,,( ,,"t4 ,?irte5?4 ,! naval or milit>y /ations = :i* ! above m5tion$ division ( "t may be e/abli%$ %all transmit signals or radiograms only dur+ ! fir/ fifte5 m9utes ( ea* h\r1 local /&>d "t1 except 9 case ( signals or radiograms relat+ to vessels 9 di/ress1 z h]e9be=e provid$4 ,,use ,,( ,,unnecess>y ,,p[]4 ,f\rte5?4 ,9 all circum/ances1 except 9 case ( signals or radiograms relat+ to vessels 9 di/ress1 all /ations %all use ! m9imum am\nt ( en]gy necess>y to c>ry out any communication desir$4 ,,g5]al ,,re/rictions ,,on ,,private ,,/ations4 ,fifte5?4 ,no private or comm]cial /ation n engag$ 9 ! transaction ( bona fide comm]cial bus9ess by radio communication or 9 exp]im5tation 9 connection ) ! developm5t & manufacture ( radio app>atus = comm]cial purposes %all use a transmitt+ wave l5g? exce$+ two hundr$ met]s1 or a trans=m] input exce$+ "o kil[att1 except by special au?ority ( ! ,secret>y ( ,comm]ce & ,labor conta9$ 9 ! lic5se ( ! /ation3 ,provid$1 ,t ! own] or op]ator ( a /ation ( ! "* m5tion$ 9 ?is regulation %all n be liable = a violation ( ! requirem5ts ( ! ?ird or f\r? regulations to ! p5alties ( "o hundr$ doll>s or tw5ty-five doll>s1 respectively1 provid$ 9 ?is section unless ! p]son ma9ta9+ or op]at+ su* /ation %all h be5 notifi$ 9 writ+ t ! said transmitt] has be5 f\nd1 ^u te/s conduct$ by ! ,gov]nm5t1 to be s adju/$ z to violate ! said ?ird & f\r? regulations1 & opportunity has be5 giv5 to said own] or op]ator to adju/ said transmitt] 9 con=mity ) said regulations4 ,,special ,,re/rictions ,,9 ,,! ,,vic9ities ,,( ,,gov]nm5t ,,/ations4 ,sixte5?4 ,no /ation ( ! "* m5tion$ 9 regulation fifte5? situat$ )9 five nautical miles ( a naval or milit>y /ation %all use a transmitt+ wave l5g? exce$+ two hundr$ met]s or a trans=m] input exce$+ "o-half kil[att4 ,,%ip ,,/ations ,,to ,,communicate ,,) ,,ne>e/ ,,%ore ,,/ations4 ,sev5te5?4 ,9 g5]al1 ! %ipbo>d /ations %all transmit _! radiograms to ! ne>e/ %ore /ation4 ,a s5d] on bo>d a vessel %all1 h[ev]1 h ! "r to designate ! %ore /ation ?r\gh :i* he desires to h 8 radiograms transmitt$4 ,if ?is c n be done1 ! wi%es ( ! s5d] are to be compli$ ) only if ! transmission c be effect$ )\t int]f]+ ) ! s]vice ( o!r /ations4 ,,limitations ,,= ,,future ,,in/allations ,,9 ,,vic9ities ,,( ,,gov]nm5t ,,/ations4 ,eighte5?4 ,no /ation on %ore n 9 actual op]ation at ! date ( ! passage ( ?is ,act %all be lic5s$ = ! transaction ( comm]cial bus9ess by radio communication )9 fifte5 nautical miles ( ! foll[+ naval or milit>y /ations1 to wit3 ,arl+ton1 ,virg9ia2 ,key ,we/1 ,florida2 ,san ,juan1 ,porto ,rico2 ,nor? ,head & ,tatoo% ,isl&1 ,wa%+ton2 ,san ,diego1 ,cali=nia2 & ^? e/abli%$ or :i* may be e/abli%$ 9 ,alaska & 9 ! ,canal ,zone2 & ! head ( ! dep>tm5t hav+ control ( su* ,gov]nm5t /ations %all1 s f> z is consi/5t ) ! transaction ( gov]nm5tal bus9ess1 arrange = ! transmission & receipt ( comm]cial radiograms "u ! provisions ( ! ,b]l9 conv5tion ( n9ete5 hundr$ & six & future int]national conv5tions or treaties to :i* ! ,unit$ ,/ates may be a p>ty1 at ea* ( ! /ations above ref]r$ to1 & %all fix ! rates !re=1 subject to control ( su* rates by ,congress4 ,at su* /ations & :]ev] & :5ev] %ore /ations op5 = g5]al public bus9ess betwe5 ! coa/ & vessels at sea "u ! provisions ( ! ,b]l9 conv5tion ( n9ete5 hundr$ & six & future int]national conv5tions & treaties to :i* ! ,unit$ ,/ates may be a p>ty %all n be s e/abli%$ z to insure a con/ant s]vice day & night )\t int]ruption1 & 9 all localities :]ev] or :5ev] su* s]vice %all n be ma9ta9$ by a comm]cial %ore /ation )9 "o hundr$ nautical miles ( a naval radio /ation1 ! ,secret>y ( ! ,navy %all1 s f> z is consi/5t ) ! transaction ( gov]nm5tal bus9ess1 op5 naval radio /ations to ! g5]al public bus9ess describ$ above1 & %all fix rates = su* s]vice1 subject to control ( su* rates by ,congress4 ,! receipts f su* radiograms %all be cov]$ into ! ,treasury z miscellane\s receipts4 ,,secrecy ,,( ,,messages4 ,n9ete5?4 ,no p]son or p]sons engag$ 9 or hav+ k ( ! op]ation ( any /ation or /ations %all divulge or publi% ! cont5ts ( any messages transmitt$ or receiv$ by su* /ation1 except to ! p]son or p]sons to :om ! same may be direct$1 or _! au?oriz$ ag5t1 or to ano!r /ation employ$ to =w>d su* message to its de/9ation1 unless legally requir$ s to d by ! c\rt ( compet5t jurisdiction or o!r compet5t au?ority4 ,any p]son guilty ( divulg+ or publi%+ any message1 except z h]e9 provid$1 %all1 on conviction !re(1 be puni%able by a f9e ( n m ?an two hundr$ & fifty doll>s or imprisonm5t = a p]iod ( n exce$+ ?ree mon?s1 or bo? f9e & imprisonm5t1 9 ! discretion ( ! c\rt4 ,,p5alties4 ,= violation ( any ( ^! regulations1 subject to :i* a lic5se "u sections "o & two ( ?is ,act may be issu$1 ! own] ( ! app>atus %all be liable to a p5alty ( "o hundr$ doll>s1 :i* may be r$uc$ or remitt$ by ! ,secret>y ( ,comm]ce & ,labor1 & = repeat$ violations ( any ( su* regulations1 ! lic5se may be revok$4 ,= violation ( any ( ^! regulations1 except z provid$ 9 regulation n9ete5?1 subject to :i* a lic5se "u section ?ree ( ?is ,act may be issu$1 ! op]ator %all be subject to a p5alty ( tw5ty-five doll>s1 :i* may be r$uc$ or remitt$ by ! ,secret>y ( ,comm]ce & ,labor1 & = repeat$ violations ( any su* regulations1 ! lic5se %all be susp5d$ or revok$4 ,,sec4 #e4 ,t e lic5se grant$ "u ! provisions ( ?is ,act = ! op]ation or use ( app>atus = radio communication %all prescribe t ! op]ator !re( %all n wilfully or malici\sly int]f]e ) any o!r radio communication4 ,su* int]f]5ce %all be deem$ a misdemeanor1 & ^u conviction !re( ! own] or op]ator1 or bo?1 %all be puni%able by a f9e ( n to exce$ five hundr$ doll>s or imprisonm5t = n to exce$ "o ye>1 or bo?4 ,,sec4 #f4 ,t ! expression radio communication z us$ 9 ?is ,act means any sy/em ( electrical communication by telegraphy or telephony )\t ! aid ( any wire connect+ ! po9ts f & at :i* ! radiograms1 signals1 or o!r communications are s5t or receiv$4 ,,sec4 #g4 ,t a p]son1 company1 or corporation )9 ! jurisdiction ( ! ,unit$ ,/ates %all n kn[+ly utt] or transmit1 or cause to be utt]$ or transmitt$1 any false or fraudul5t di/ress signal or call or false or fraudul5t signal1 call1 or o!r radiogram ( any k9d4 ,! p5alty = s utt]+ or transmitt+ a false or fraudul5t di/ress signal or call %all be a f9e ( n m ?an two ?\s& five hundr$ doll>s or imprisonm5t = n m ?an five ye>s1 or bo?1 9 ! discretion ( ! c\rt1 = ea* & e su* (f5se1 & ! p5alty = s utt]+ or transmitt+1 or caus+ to be utt]$ or transmitt$1 any o!r false or fraudul5t signal1 call1 or o!r radiogram %all be a f9e ( n m ?an "o ?\s& doll>s or imprisonm5t = n m ?an two ye>s1 or bo?1 9 ! discretion ( ! c\rt1 = ea* & e su* (f5se4 ,,sec4 #h4 ,t a p]son1 company1 or corporation %all n use or op]ate any app>atus = radio communication on a =eign %ip 9 t]ritorial wat]s ( ! ,unit$ ,/ates o!rwise ?an 9 accordance ) ! provisions ( sections f\r & sev5 ( ?is ,act & s mu* ( section five z imposes a p5alty = int]f]5ce4 ,save z a=esaid1 no?+ 9 ?is ,act %all apply to app>atus = radio communication on any =eign %ip4 ,,sec4 #i4 ,t ! trial ( any (f5se "u ?is ,act %all be 9 ! di/rict 9 :i* x is committ$1 or if ! (f5se is committ$ ^u ! high seas or out ( ! jurisdiction ( any p>ticul> ,/ate or di/rict ! trial %all be 9 ! di/rict :]e ! (f5d] may be f\nd or into :i* he %all be fir/ br\ght4 ,,sec4 #aj4 ,t ?is ,act %all n apply to ! ,phillipp9e ,isl&s4 ,,sec4 #aa4 ,t ?is ,act %all take effect & be 9 =ce on & aft] f\r mon?s f its passage4 ,approv$1 ,augu/ #ac1 #aiab4 ,,li/ ,,( ,,works ,,on ,,electrical ,,sci5ce ,,publi%$ ,,& ,,= ,,sale ,,by ,d4 ,,van ,,no/r& ,,company1 99#be ,p>k ,place1 ,new ,york499 99,,abbott1 ,a4 ,v4 ,! ,electrical ,transmission ( ,en]gy499 ,a ,manual = ! ,design ( ,electrical ,circuits4 ,fif? ,edition1 enl>g$ & rewritt54 ,) _m ,diagrams1 ,engrav+s & ,fold+ ,plates4 #hvo41 clo?1 #fge pp ,net1 #e4jj 99,,arnold1 ,e4 ,armature ,w9d+s ( ,direct-,curr5t ,dynamos499 ,ext5sion & ,application ( a g5]al ,w9d+ ,rule4 ,translat$ f ! orig9al ,g]man by ,francis ,b4 ,de,cress4 ,illu/rat$4 #hvo4 clo?1 #abd pp #b4jj 99,,a%e1 ,s4 ,w4 ,electricity ,exp]im5tally & ,practically ,appli$499 ,second ,edition4 #dbb illu/rations4 #abmo41 clo?1 #cge pp4 ,net1 #b4jj 99,,a%e1 ,s4 ,w41 & ,,keiley1 ,j4 ,d4 ,electric ,railways ,!oretically & ,practically ,treat$499 ,illu/rat$4 #abmo41 clo?4 99,vol4 ,i4 ,roll+ ,/ock499 ,second ,edition4 #bhe pp ,net1 #b4ej 99,vol4 ,,ii4 ,sub/ations & ,di/ribut+ ,sy/ems499 #bif pp ,net1 #b4 #ej 99,,atk9son1 ,a4 ,a4 ,electrical & ,magnetic ,calculations499 ,= ! use ( ,electrical ,eng9e]s & o!rs int]e/$ 9 ! ,!ory & ,application ( ,electricity & ,magnetism4 ,f\r? ,edition1 revis$ ,illu/rat$4 #abmo1 clo?1 #caj pp ,net1 #a4ej 99,,atk9son1 ,,philip4 ,! ,elem5ts ( ,dynamic ,electricity & ,magnetism499 ,f\r? ,edition4 ,illu/rat$4 #abmo41 clo?1 #dje pp4 #b4jj - 99,elem5ts ( ,electric ,light+199 includ+ ,electric ,g5]ation1 ,measurem5t1 ,/orage1 & ,di/ribution4 ,t5? ,edition1 fully revis$ & new matt] add$4 ,illu/rat$4 #abmo41 clo?1 #bhj pp #a4ej - 99,p[] ,transmitt$ by ,electricity & ,appli$ by ! ,electric ,motor199 includ+ ,electric ,railway ,con/ruction4 ,illu/rat$4 ,f\r? ,edition1 fully revis$ & new matt] add$4 #abmo41 clo?1 #bda pp4 #b4jj 99,,au/91 ,e4 ,s+le-,phase ,electric ,railways499 #cdf illu/rations #h x #aa1 clo?1 #cjh pp ,net1 #e4jj 99,,ayrton1 ,,h]?a4 ,! ,electric ,arc499 ,illu/rat$4 #hvo41 clo?1 #dgi pp ,net1 #e4jj 99,,bak]1 ,j4 ,t4 ,! ,telegraphic ,transmission ( ,photographs499 #fc illu/rations4 #abmo41 clo?1 #aee pp ,net1 #a4be 99,,b>ham1 ,g4 ,b4 ,developm5t ( ! ,inc&esc5t ,electric ,lamp499 #be illu/rations1 #b plates1 #e x #h clo?4 #bjf pp #b4jj 99,,b$ell1 ,,fr$]ick4 ,direct & ,alt]nat+ ,curr5t ,manual499 ,) directions = te/+ & a discussion ( ! !ory ( electrical app>atus4 ,second ,edition1 greatly enl>g$4 ,assi/$ by ,c4 ,a4 ,pi]ce4 ,illu/rat$4 #f x #i1 clo?1 #cgc pp ,net1 #b4jj 99,,bla9e1 ,,rob]t ,g4 ,! ,calculus & ,its ,applications499 ,a practical treatise = beg9n]s especially eng9e]+ /ud5ts4 #gi illu/rations4 #abmo41 clo?1 #ccj pp ,net1 #a4ej 99,,bonney1 ,g4 ,e4 ,! ,electro-,plat]'s ,h& ,book499 ,a ,manual = ,amateurs & ,"y ,/ud5ts ( ,electro-,metallurgy4 ,fif? ,edition1 enl>g$4 #fa ,illu/rations4 #abmo41 clo?1 #bjh pp #a4bj 99,,bottone1 ,s4 ,r4 ,magnetos ,= ,automobili/s2 ,h[ ,made & ,h[ ,us$99 ,a h&book ( practical in/ruction on ! manufacture & adaptation ( ! magneto to ! ne$s ( ! motori/4 ,second ,edition1 enl>g$4 #eb illu/rations4 #abmo41 clo?1 #aah pp ,net1 #a4jj 99,,broadfoot1 ,s4 ,k4 ,motors1 ,second>y ,batt]ies & ,accessory ,app>atus499 #af illu/rations4 #afmo41 clo?4 #ajjpp4 7,in/allation ,manuals ,s]ies7 ,net1 #j4ge 99,,br\ghton1 ,h4 ,h4 ,electric ,canes499 ,_! design1 con/ruction & application4 #fjj illu/rations & plates4 #abj tables1 #f x #i1 clo?1 #hdh pp ,net1 #i4jj 99,,*ild1 ,c4 ,d4 ,electric ,arcs499 ,exp]im5ts ^u arcs betwe5 diff]5t electrodes 9 v>i\s environm5ts & _! explanation4 #eh illu/rations4 #e x #g1 clo?1 #bjc pp ,net1 #b4jj 99,,collis1 ,a4 ,g4 ,high & ,l[ ,t5sion ,swit*ge> ,design499 #id illu/rations & fold+ plates1 #f x #i1 clo?1 #bcc pp ,net1 #c4ej - 99,swit*ge> & ,! ,control ( ,electric ,circuits499 #dg illu/rations4 #d #a_/b x #f #a_/b1 clo?1 #he pp4 7,in/allation ,manuals ,s]ies7 ,net1 #j4ej 99,,com/ock1 ,d4 ,f41 & ,,trol&1 ,l4 ,t4 ,! ,nature ( ,matt] & ,electricity499 ,an outl9e ( mod]n views4 ,illu/rat$4 #e x #g1 clo?1 #bjj pp ,net1 #b4jj 99,,coop]1 ,w4 ,r4 ,prim>y ,batt]ies3 _! ,!ory1 ,con/ruction1 & ,use99 ,new ,edition 9 ,press 99,,craig1 ,j4 ,w41 & ,,woodw>d1 ,w4 ,p4 ,que/ions & ,answ]s ,ab\t ,electrical ,app>atus499 ,?ird edition revis$ & enl>g$4 ,illu/rat$4 #d x #f ,lea!r1 #bef pp ,net1 #a4ej 99,,cramp1 ,w4 ,cont9u\s ,curr5t ,ma*9e ,design499 #acg illu/ration4 #hvo41 clo?1 #bdj pp ,net1 #b4ej 99,,cre$ ,y1 ,f4 ,s+le-,phase ,commutator ,motors499 #ih illu/rations1 #f x #i1 clo?1 #abj pp ,net1 #b4jj 99,,crock]1 ,f4 ,b4 ,electric ,light+499 ,a ,practical ,exposition ( ! ,art = ! use ( ,electricians1 ,/ud5ts1 & o!rs int]e/$ 9 ! ,in/allation or ,op]ation ( ,electric ,light+ ,plants4 - 99,vol4 ,i4 ,! ,g5]at+ ,plant994 ,sev5? ,edition1 entirely revis$4 ,illu/rat$4 #hvo41 clo?1 #dhb pp #c4jj - 99,vol4 ,,ii4 ,di/ribut+ ,sy/em & ,lamps499 ,six? ,edition4 ,illu/rat$ #hvo41 clo?1 #eje pp4 99,,crock]1 ,f4 ,b41 & ,,ar5dt1 ,m4 ,electric ,motors3 ,_! ,action1 ,control1 & ,application499 ,second ,edition1 ,revis$ & ,enl>g$4 #afi illu/rations4 #f #a_/d x #i #a_/d1 clo?1 #cae pp ,net1 #b4ej 99,,crock]1 ,f4 ,b41 & ,,:eel]1 ,s4 ,s4 ,! ,managem5t ( ,electrical ,ma*9]y499 ,be+ a ?or\ghly revis$ & rewritt5 edition ( ! au?ors' ,practical ,managem5t ( ,dynamos & ,motors4 ,eigh? ,edition4 ,illu/rat$4 #afmo41 clo?1 #bcb pp ,net1 #a4jj 99,,cu%+1 ,h4 ,c41 ,jr4 ,/&>d ,wir+ = ,electric ,light & ,p[]99 ,illu/rat$4 #afmo41 lea!r1 #aef pp #a4jj 99,,cu%+1 ,h4 ,c41 ,jr4 & ,,h>rison1 ,n4 ,c5tral ,/ation ,managem5t499 #e #a_/b x #g #a_/d clo?1 #dag pp ,net1 #b4jj 99,,davies1 ,f4 ,h4 ,electric ,p[] & ,traction499 ,illu/rat$4 #hvo41 clo? #bic pp4 7,van ,no/r&'s ,we/m9/] ,s]ies47 ,net1 #b4jj - 99,f\ndations & ,ma*9]y ,fix+499 #eb illu/rations4 #afmo41 clo?1 #adf pp4 7,in/allations ,manuals ,s]ies7 ,net1 #a4jj 99,,del ,,m>1 ,w4 ,a4 ,electric ,p[] ,conductors499 ,second edition revis$4 #fi illu/rations4 #e #a_/b x #h1 clo?1 #ccj pp ,net1 #b4jj 99,,devey1 ,r4 ,g4 ,mill & ,factory ,wir+499 #abf illu/rations4 #afmo41 clo?1 #bji pp4 7,in/allation ,manuals ,s]ies7 ,net1 #a4jj 99,,d+]1 ,lieut4 ,h4 ,c4 ,h&book = ! ,c>e & ,op]ation ( ,naval ,ma*9]y499 ,second ,edition4 #abd ,illu/rations4 #afmo41 clo?1 #cjb pp ,net1 #b4jj 99,,duncan1 ,w4 ,g4 & ,,p5man1 ,d4 ,electrical ,equipm5t ( ,colli]ies499 #aeg illu/rations1 #f #a_/b x #h #c_/d1 clo?1 #cbi pp ,net1 #d4jj 99,,dwight1 ,h4 ,b4 ,transmission ,l9e ,=mulas = ,electrical ,eng9e]s & ,eng9e]+ ,/ud5ts499 #bg illu/rations4 #b fold+ plates1 #abmo1 clo?1 #adc pp ,net1 #b4jj 99,,dynamic ,,electricity399 ,its ,mod]n ,use & ,measurem5t1 *iefly 9 its application to ,electric ,light+ & ,telegraphy1 includ+3 #a4 ,"s ,po9ts 9 ,electric ,light+1 by ,dr4 ,john ,hopk9son4 #b4 ,on ! ,treatm5t ( ,electricity = ,comm]cial ,purposes1 by ,j4 ,n4 ,%oolbr$4 #c4 ,electric-,light ,ari?metic1 by ,r4 ,e4 ,day1 ,m4,e4 ,f\r? ,edition4 ,illu/rat$4 #afmo41 bo>ds1 #aff pp4 7,no4 #ga ,van ,no/r&'s ,sci5ce ,s]ies47 #ej c5ts 99,,eck1 ,j4 ,light1 ,radiation & ,illum9ation499 ,translat$ f ! ,g]man ( ,paul ,hogn]4 #ei illu/rations4 #e #a_/b x #h1 clo?1 #ajj pp4 ,net1 #b4ej 99,,eccles1 ,w4 ,h4 ,wireless ,telegraphy & ,telephony499 ,illu/rat$4 #e x #h #a_/b half lea!r1 #dah pp ,net1 #d4ej 99,,eddy1 ,l4 ,c4 ,laboratory ,manual ( ,alt]nat+ ,curr5ts499 #ba illu/rations1 #e #a_/b x #h1 clo?1 #bf pp ,net1 #ej c5ts 99,,edl]1 ,r4 ,swit*es & ,swit*ge>499 ,translat$ by ,ph4 ,lauba*4 #cce illu/rations4 #f #a_/b x #i1 clo?1 #dab pp ,net1 #d4jj 99,,edgcumbe1 ,k4 ,indu/rial ,electrical ,measur+ ,in/rum5ts499 ,illu/rat$4 #h vo41 clo?1 #bbg pp4 99,,eng9e]+ ,,z ,a ,,c>e]499 ,by ,prom95t ,eng9e]s4 ,edit$ by ,c4 ,e4 ,dray] & ,f4 ,h4 ,newell4 #e #a_/d x #g #a_/b1 #bbf pp4 ,pap] #ge c5ts1 clo? #a4jj 99,,ew+1 ,j4 ,a4 ,magnetic ,induction 9 ,iron & o!r ,metals499 ,?ird ,edition1 revis$4 ,illu/rat$4 #hvo41 clo?1 #cic pp ,net1 #d4jj 99,,fi%]1 ,h4 ,k4 ,c41 & ,,d>by1 ,w4 ,c4 ,/ud5ts' ,guide to ,subm>9e ,cable ,te/+499 ,f\r? ,edition1 enl>g$4 ,illu/rat$4 #hvo41 clo?1 #beb pp ,net1 #c4ej 99,,flem+1 ,j4 ,a41 ,pr(4 ,! ,alt]nate-,curr5t ,trans=m] 9 ,!ory & ,practice499 99,vol4 ,i43 ,! ,induction ( ,electric ,curr5ts499 ,fif? ,issue4 ,illu/rat$4 #evo41 clo?1 #fda pp3 ,net1 #e4jj 99,vol4 ,,ii43 ,! ,utilization ( ,induc$ ,curr5ts499 ,?ird ,issue4 ,illu/rat$4 #hvo41 clo?1 #ehg pp ,net1 #e4jj - 99,propagation ( ,electric ,curr5ts 9 ,telephone & ,telegraph ,conductors499 ,illu/rat$4 #f #a_/b x #i #a_/b1 clo?1 #cbc pp ,net1 #c4jj - 99,h&book = ! ,electrical ,laboratory & ,te/+ ,room499 ,two ,volumes4 ,illu/rat$4 #hvo41 clo?1 #aafj pp4 ,ea* vol ,net1 #e4jj 99,,fo/]1 ,h4 ,a4 ,) ! ,collaboration ( ,em95t ,speciali/s4 ,electrical ,eng9e]s' ,pocket ,book499 ,a h&book ( useful data = ,electricians & ,electrical ,eng9e]s4 ,) innum]able ,tables1 ,diagrams1 & ,figures4 ,! mo/ complete book ( its k9d ev] publi%$1 treat+ ( ! late/ & be/ ,practice 9 ,electrical ,eng9e]+4 ,sev5? ,edition1 completely revis$ & enl>g$4 ,fully ,illu/rat$4 ,pocket ,size4 ,lea!r4 ,?umb ,index$4 #afcf pp #e4jj - 99,eng9e]+ ,valuation ( ,public ,utilities & ,factories499 #ej blank =ms4 #f x #i1 clo?1 #cfa pp ,net1 #c4jj - 99,electrical ,co/ ,data1 ,e/imates & ,work+ ,tables499 ,9 ,press 99,,f[le1 ,f4 ,f4 ,! ,protection ( ,railroads f ,ov]head ,transmission ,l9e ,cross+s499 #ce illu/rations4 #abmo41 clo?1 #gf pp ,net1 #a4ej4 99,,freudema*]1 ,p4 ,w4 ,electrical ,m9+ ,in/allations499 #cf illu/rations4 #afmo41 clo?1 #aib pp4 7,in/allation ,manuals ,s]ies7 ,net1 #a4jj 99,,fri?1 ,j4 ,alt]nat+ ,curr5t ,design499 #bg illu/rations4 #f x #i1 clo?1 #aca pp ,net1 #b4jj 99,,g>r>d1 ,c4 ,c4 ,electric ,swit* & ,controll+ ,ge>499 #dbc illu/rations1 #e #c_/d x #h #c_/d1 clo?1 #fef pp ,net1 #f4jj 99,,gant1 ,l4 ,w4 ,elem5ts ( ,electric ,traction = ,motorm5 & ,o!rs499 ,illu/rat$ ) ,diagrams4 #hvo41 clo?1 #bag pp ,net1 #b4jj 99,,ge>1 ,h4 ,b4 & ,,williams1 ,p4 ,f4 ,electric ,c5tral ,/ation ,di/ribution ,sy/ems4 ,_! ,design & ,con/ruction499 ,second ,edition1 revis$ & enl>g$4 #ahg illu/rations4 #e #a_/b x #g #a_/b1 clo?1 #dee pp ,net1 #c4ej 99,,g]h>di1 ,c4 ,h4 ,w4 ,electricity ,met]s2 _! ,con/ruction & ,managem5t499 ,a practical manual = eng9e]s & /ud5ts4 ,illu/rat$4 #hvo41 clo?1 #ccg pp ,net1 #d4jj 99,,goldsmi?1 ,,rudolf4 ,! ,alt]nat+ ,curr5t ,commutator ,motor4 ,! ,leakage ( ,induction ,motors499 ,9 "o volume4 #bdg illu/rations4 #e #a_/d x #h #c_/d1 clo? ,net1 #c4jj 99,,gore1 ,,george4 ,! ,art ( ,electrolytic ,sep>ation ( ,metals 7,!oretical & ,practical7499 ,illu/rat$4 #hvo41 clo?1 #bie pp ,net #c4ej 99,,gro?1 ,l4 ,a4 ,weld+ & ,cutt+ ,metals by ,aid ( ,gases or ,electricity499 #abd illu/rations4 #h vo41 clo?1 #bhj pp4 7,van ,no/r&'s ,we/m9i/] ,s]ies7 ,net1 #b4jj 99,,hall]1 ,g4 ,f4 & ,,cunn+ham1 ,e4 ,t4 ,! ,tesla ,high ,frequ5cy ,coil2 its con/ruction & uses499 #abmo41 clo?1 #ef illu/rations1 #acj pp ,net1 #a4be 99,,hask9s1 ,c4 ,h4 ,! ,galvanomet] & its ,uses4 ,a ,manual = ,electricians & ,/ud5ts499 ,fif? ,edition1 revis$4 ,illu/rat$4 #afmo41 morocco1 #ge pp #a4ej 99,,hausmann1 ,e4 ,telegraph ,eng9e]+4 ,a ,manual = ,practic+ ,telegraph1 ,eng9e]s & ,eng9e]+ ,/ud5ts499 #aib ,illu/rations4 clo?1 #daf pp ,net1 #c4jj 99,,hay1 ,,alfr$4 ,an ,introductory ,c\rse ( ,cont9u\s-,curr5t ,eng9e]+499 ,illu/rat$4 #hvo41 clo?1 #cbg pp ,net1 #b4ej 99,,hayes1 ,h4 ,v4 ,public ,utilities1 ,_! ,co/ ,new & ,depreciation499 #e #c_/d x #h #a_/b1 clo?1 #bge pp ,net1 #b4jj - 99,public ,utilities2 ,_! ,fair ,pres5t ,value & ,return499 #e #a_/b x #h #a_/b1 clo?1 #bjj pp ,net1 #b4jj 99,,hea!r1 ,h4 ,j4 ,electrical ,eng9e]+ = ,me*anical & ,m9+ ,eng9e]s499 #ahc illu/rations4 #e x #h1 clo?1 #cdd pp ,net1 #c4ej 99,,heaviside1 ,o4 ,electromagnetic ,!ory4 ,two ,volumes ) ,_m ,diagrams499 #hvo41 clo?1 #ajjf pp4 ,ea* ,vol ,net1 #e4jj 99,vol4 ,,iii499 #ebi pp ,net1 #g4ej 99,,hob>t1 ,h4 ,m4 ,heavy ,electrical ,eng9e]+499 ,illu/rat$4 #hvo41 clo?1 #cch pp ,net1 #d4ej - 99,design ( ,/atic ,trans=m]s499 #aja illu/rations4 #f x #i1 clo?1 #ahi pp ,net1 #b4jj - 99,electricity4 ,a text-book design$ 9 p>ticul> = eng9e]+ /ud5ts499 #aae illu/rations4 #dc tables4 #hvo44 clo?1 #bff pp1 ,net1 #b4jj - 99,electric ,tra9s499 #hh illu/rations4 #hvo41 clo?1 #bbj pp ,net1 #b4ej - 99,electric ,propulsion ( ,%ips499 #dd illu/rations4 #hvo41 clo?1 #afg pp4 ,net1 #b4jj 99,,hobbs1 ,w4 ,r4 ,p4 ,! ,ari?metic ( ,electrical ,measurem5ts499 ,) num]\s examples1 fully work$4 ,sixte5? ,edition1 revis$ & edit$ ) six additional *apt]s by ,a4 ,r4 ,palm]4 #abmo4 clo?1 #abf pp #ej c5ts4 99,,h\/\n1 ,r4 ,a4 ,/udies 9 ,light ,production499 #bb illu/rations4 #e #c_/d x #h #c_/d1 clo?1 #abj pp ,net1 #b4jj 99,,hut*9son1 ,r4 ,w41 ,jr4 ,long-,di/ance ,electric ,p[] ,transmission399 ,be+ a ,treatise on ! ,hydro-,electric ,g5]ation ( ,en]gy2 ,its ,trans=mation1 ,transmission1 & ,di/ribution4 ,second ,edition4 ,illu/rat$4 #abmo41 clo?1 #cej pp ,net1 #c4jj - 99& ,,?omas1 ,w4 ,d4 ,electricity 9 ,m9+499 ,be+ a !oretical & practical treatise on ! con/ruction1 op]ation & ma9t5ance ( electrical m9+ ma*9]y4 #abmo41 clo? ,9 ,press 99,,inc&esc5t ,,electric ,,light+499 ,a ,practical ,description ( ! ,edison ,sy/em1 by ,h4 ,latim]4 ,to :i* is add$3 ,! ,design & ,op]ation ( ,inc&esc5t ,/ations1 by ,c4 ,j4 ,field2 ,a ,description ( ! ,edison ,electrolyte ,met]1 by ,a4 ,e4 ,k5nelly2 & a ,pap] on ! ,maximum ,effici5cy ( ,inc&esc5t ,lamps1 by ,t4 ,w4 ,h[ell4 ,fif? ,edition4 ,illu/rat$4 #afmo41 clo?1 #adj pp4 7,no4 #eg ,van ,no/r&'s ,sci5ce ,s]ies47 #ej c5ts 99,,induction ,,coils3 ,h[ ,made & ,h[ ,us$499 ,elev5? ,edition4 ,illu/rat$4 #afmo41 clo?1 #abc pp4 7,no4 #ec ,van ,no/r&'s ,sci5ce ,s]ies47 #ej c5ts 99,,jehl1 ,,francis4 ,! ,manufacture ( ,c>bons = ,electric ,light+ & o!r purposes499 ,illu/rat$ ) num]\s ,diagrams1 ,tables1 & ,fold+ ,plates4 #hvo41 clo?1 #bcb pp ,net1 #d4jj 99,,johnson1 ,j4 ,h4 ,arc ,lamps & ,accessory ,app>atus499 #bj illu/rations4 #afmo41 clo?1 #ace pp4 7,in/allation ,manuals ,s]ies7 ,net1 #ge c5ts4 99,,johnson1 ,t4 ,m4 ,%ip ,wir+ & ,fitt+499 #dg illu/rations4 #afmo41 clo?1 #ib pp4 7,in/allation ,manuals ,s]ies7 ,net1 #ge c5ts4 99,,jones1 ,,h>ry ,c4 ,! ,electrical ,nature ( ,matt] & ,radioactivity499 ,?ird ,edition1 revis$4 #e #a_/b x #h #a_/b1 clo?1 #bah pp ,net1 #b4jj 99,,kapp1 ,,gisb]t4 ,alt]nate-,curr5t ,ma*9]y499 ,illu/rat$4 #afmo41 clo?1 #aij pp4 7,no4 #if ,van ,no/r&'s ,sci5ce ,s]ies7 #ej c5ts 99,,kapp]1 ,f4 ,ov]head ,transmission ,l9es & ,di/ribut+ ,circuits499 #big illu/rations4 #b plates1 #g #a_/d x #aj1 clo?1 #caj pp ,net1 #d4jj 99,,k5n$y1 ,r4 ,electrical ,in/allations ( ,electric ,light1 ,p[]1 & ,traction ,ma*9]y499 ,illu/rat$4 #hvo41 clo?1 #e vols4 ,! set #ae4jj4 ,ea* #c4ej 99,,k5nelly1 ,a4 ,e4 ,!oretical ,elem5ts ( ,electro-,dynamic ,ma*9]y499 ,vol4 ,i4 ,illu/rat$4 #hvo41 clo?1 #ij pp #a4ej 99,,k]%aw1 ,j4 ,b4 ,c4 ,! ,electric ,furnace 9 ,iron & ,/eel ,production499 ,illu/rat$4 #hvo41 clo?1 #gd pp ,net1 #a4ej - 99,electrometallurgy499 ,illu/rat$4 #hvo41 clo?1 #cjc pp4 7,van ,no/r&'s ,we/m9/] ,s]ies47 ,net1 #b4jj 99,,k9zbrunn]1 ,c4 ,cont9u\s-,curr5t ,armatures2 _! ,w9d+ & ,con/ruction499 #gi ,illu/rations4 #hvo41 clo?1 #hj pp ,net1 #a4ej - 99,alt]nate-,curr5t ,w9d+s2 _! ,!ory & ,con/ruction499 #hi ,illu/rations4 #hvo41 clo?1 #hj pp ,net1 #a4ej - 99,! ,te/+ ( ,alt]nat+ ,curr5t ,ma*9es 9 ,laboratories & ,te/ ,rooms499 ,a practical "w = /ud5ts & eng9e]s4 ,vol ,i4 ,g5]al ,te/s2 ,trans=m]s1 ,alt]nators4 #ada illu/rations4 #e #a_/b x #h #c_/d1 clo?1 #afd pp ,net1 #b4jj 99,,kl+5b]g1 ,g4 ,l>ge ,electric ,p[] ,/ations499 ,_! design & con/ruction1 ) examples ( exi/+ /ations4 #ahj illu/rations1 #g plates1 #g x #aj1 clo?1 #bfj pp ,net1 #e4jj 99,,koe/]1 ,f4 ,hydroelectric ,developm5ts & ,eng9e]+499 ,a practical & !oretical treatise on ! developm5t1 design1 con/ruction1 equipm5t & op]ation ( hydroelectric transmission plants4 ,second ,edition4 #ejj illu/rations4 #dto41 clo?1 #dge pp4 ,net1 #e4jj - 99,/eam-,electric ,p[] ,plants499 ,a practical treatise on ! design ( c5tral light & p[] /ations & _! economical con/ruction & op]ation4 ,second ,edition4 ,fully ,illu/rat$4 #dto41 clo? #dee pp ,net1 #e4jj 99,,lanca/]1 ,m4 ,electric ,cook+1 ,heat+ & ,clean+499 ,edit$ by ,w4 ,e4 ,lanca/]1 ,am]ican ,edition by ,s4 ,l4 ,coles1 #cje illu/rations1 #f x #h #a_/b1 clo? #cdj pp ,net1 #a4jj 99,,l>n]1 ,e4 ,t4 ,! ,pr9ciples ( ,alt]nat+ ,curr5ts = ,/ud5ts ( ,electrical ,eng9e]+499 ,illu/rat$ ) ,diagrams4 #abmo41 clo?1 #add pp ,net1 #a4be 99,,lem/rom1 ,s4 ,electricity 9 ,agriculture & ,horticulture499 ,illu/rat$4 #hvo41 clo? ,net1 #a4ej 99,,liv]more1 ,v4 ,p41 & ,,williams1 ,j4 ,h[ to ,become a ,compet5t ,motorman399 ,be+ a practical treatise on ! prop] me?od ( op]at+ a /reet-railway motor-c>2 also giv+ details h[ to ov]come c]ta9 defects4 ,second ,edition4 ,illu/rat$4 #afmo41 clo?1 #bdg pp ,net1 #a4jj 99,,liv+/one1 ,r4 ,me*anical ,design & ,con/ruction ( ,g5]ators499 #abb illu/rations4 #e #a_/b x #h #c_/d1 clo?1 #bbh pp ,net1 #c4ej - 99,me*anical ,design & ,con/ruction ( ,commutators499 #fb illu/rations1 #e #a_/b x #h #c_/d1 clo?1 #ic pp ,net1 #b4be 99,,lockwood1 ,t4 ,d4 ,electricity1 ,magnetism1 & ,electro-,telegraphy499 ,a ,practical ,guide & ,h&book ( ,g5]al ,in=mation = ,electrical ,/ud5ts1 ,op]ators1 & ,inspectors4 ,f\r? ,edition4 ,illu/rat$4 #hvo41 clo?1 #cgd pp #b4ej 99,,lodge1 ,,oliv] ,j4 ,signall+ ,across ,space ,)\t ,wires399 ,be+ a description ( ! "w ( ,h]tz & 8 successors4 ,?ird ,edition ,illu/rat$4 #hvo41 clo? ,net1 #b4jj 99,,lor+1 ,a4 ,e4 ,a ,h&book ( ! ,electro-,magnetic ,telegraph99 ,f\r? ,edition1 revis$4 ,illu/rat$4 #afmo41 clo?1 #aaf pp4 7,no4 #ci ,van ,no/r&'s ,sci5ce ,s]ies47 #ej c5ts 99,,luckte%1 ,m4 ,color & ,its ,application499 #abf illu/rations1 #d color plates4 #f x #i1 clo?1 #cej pp #c4jj - 99,light & ,%ade & ,_! ,applications499 #ace illu/rations1 #aj tables1 #f #a_/d x #i #a_/d1 clo?1 #bgh pp ,net1 #b4ej 99,,malcolm1 ,w4 ,h4 ,!ory ( ! ,subm>9e ,telegraph ,cable499 ,9 ,press 99,,mansfield1 ,a4 ,n4 ,electromagnets3 ,_! ,design & ,con/ruction499 ,second ,edition4 ,illu/rat$4 #afmo ,m clo?1 #aee pp4 7,no4 #fd ,van ,no/r&'s ,sci5ce ,s]ies47 #ej c5ts - 99,manufacture ( ,electric ,light ,c>bons499 ,illu/rat$4 #e #a_/b x #h1 clo?4 ,net1 #a4jj 99,,massie1 ,w4 ,w41 & ,,und]bill1 ,c4 ,r4 ,wireless ,telegraphy & ,telephony ,popul>ly ,expla9$499 ,) a *apt] by ,nikola ,tesla4 ,illu/rat$4 #abmo41 clo?1 #hb pp ,net1 #a4jj 99,,maurice1 ,w4 ,electrical ,bla/+ ,app>atus & ,explosives1 ) special ref]5ce to colli]y practice499 ,illu/rat$4 #hvo41 clo?4 #afg pp ,net1 #c4ej - 99,! ,%ot ,fir]'s ,guide499 ,a practical manual on bla/+ & ! prev5tion ( bla/+ accid5ts4 #gh illu/rations4 #hvo41 clo?4 #bab pp ,net1 #a4ej 99,,miessn]1 ,b4 ,f4 ,radiodynamics499 ,! wireless control ( torp$oes & o!r me*anisms4 #aab illu/rations1 #e #a_/b x #h #a_/d1 clo?1 #baa pp4 ,net1 #b4jj 99,,monckton1 ,c4 ,c4 ,f4 ,radio ,telegraphy499 #agc ,illu/rations4 #hvo clo?1 #bgb pp4 7,van ,no/r&'s ,we/m9/] ,s]ies47 ,net1 #b4jj 99,,montgom]y1 ,j4 ,w4 ,electric ,wir+ ,specifications99 #d x #f #a_/b1 clo?1 #ajg pp ,net1 #a4ej 99,,morecr(t1 ,j4 ,h4 & ,,hehre1 ,f4 ,w4 ,a ,%ort ,c\rse 9 ,te/+ ( ,electrical ,ma*9]y499 ,?ird ,edition4 ,illu/rat$4 #hvo41 clo?1 #afj pp ,net1 #a4ej 99,,morgan1 ,,alfr$ ,p4 ,wireless ,telegraph ,con/ruction = ,amateurs499 ,?ird ,edition4 #afg illu/rations4 #e #a_/b x #g #a_/b1 clo?1 #bcf pp ,net1 #a4ej 99,,n]z1 ,f4 ,se>*lights1 ,_! ,!ory1 ,con/ruction & ,application499 ,translat$ by ,c4 ,rodg]s4 #dg illu/rations4 #f x #h11 clo?1 #ade pp4 ,net1 #c4jj 99,,niph]1 ,,francis ,e4 ,!ory ( ,magnetic ,measurem5ts499 ,) an ,app5dix on ! ,me?od ( ,lea/ ,squ>es4 ,illu/rat$4 #abmo41 clo?1 #id pp #a4jj 99,,ohm1 ,g4 ,s4 ,! ,galvanic ,circuit ,inve/igat$ ,ma!matically499 ,b]l91 #ahbg4 ,translat$ by ,william ,francis4 ,) ,preface & ,notes by ,?os4 ,d4 ,lockwood4 ,second ,edition4 ,illu/rat$4 #afmo41 clo?1 #bfi pp4 7,no4 #ajb ,van ,no/r&'s ,sci5ce ,s]ies47 #ej c5ts 99,,olsson1 ,,&rew4 ,motor ,control z us$ 9 ,connection ) ,turret ,turn+ & ,gun ,elevat+499 7,! ,w>d ,leon>d ,sy/em47 #ac illu/rations4 #abmo41 pap]1 #bg pp4 7,u4 ,s4 ,navy ,electrical ,s]ies ,no4 #a47 ,net1 4#ej 99,,oud91 ,,maurice ,a4 ,/&>d ,polyphase ,app>atus & ,sy/ems499 ,six? ,edition1 revis$4 ,illu/rat$ ) _m ,photo-reproductions1 ,diagrams1 & ,tables4 #hvo41 clo?1 #cfi pp ,net1 #c4jj 99,,palaz1 ,a4 ,treatise on ,indu/rial ,photometry499 ,specially appli$ to ,electric ,light+4 ,translat$ f ! ,fr5* by ,g4 ,w4 ,patt]son1 ,jr41 & ,m4 ,r4 ,patt]son4 ,second ,edition4 ,fully ,illu/rat$4 #hvo41 clo?1 #cbd pp #d4jj 99,,p>r1 ,g4 ,d4 ,a4 ,electrical ,eng9e]+ ,measur+ ,in/rum5ts = ,comm]cial & ,laboratory ,purposes499 ,) #cgj ,diagrams & ,engrav+s4 #hvo41 clo?1 #cbh pp ,net1 #c4ej 99,,p>%all1 ,h4 ,p41 & ,,hob>t1 ,h4 ,m4 ,armature ,w9d+s ( ,electric ,ma*9es499 ,?ird ,edition4 ,) #adj full-page ,plates1 #fe ,tables1 & #afe pages ( descriptive lett]-press4 #dvo41 clo?1 #cjj pp4 #g4ej - 99,electric ,railway ,eng9e]+499 ,) #dcg ,figures & ,diagrams & _m ,tables4 #dto41 clo?1 #dge pp ,net1 #g4ej - 99,electric ,ma*9e ,design499 ,be+ a revis$ & enl>g$ edition ( ,electric ,g5]ators4 #fdh ,illu/rations4 #dvo41 half morocco1 #fja pp ,net1 #ab4ej 99,,pat*ell ,w4 ,h4 ,application ( ,electric ,p[] to ,m9es & heavy ,indu/ries499 #ia illu/rations #f #a_/b x #i #a_/d1 clo?1 #bjc pp ,net1 #d4jj 99,,patt]son1 ,g4 ,w4 ,l4 ,wir+ ,calculations = ,light & ,p[] ,in/allations499 #aci illu/rations1 #e #a_/d x #g #a_/d4 clo?1 #bjc pp ,net1 #b4jj - 99,electric ,m9e ,signall+ & ,in/allations499 ,illu/rat$4 #e #a_/d x #g #a_/h1 #aaj pp ,net1 #a4ej 99,,p]r9e1 ,f4 ,a4 ,c4 ,conductors = ,electrical ,di/ribution3 ,_! ,manufacture & ,mat]ials ! ,calculation ( ,circuits1 ,pole ,l9e ,con/ruction1 ,und]gr\nd ,work+1 & o!r ,uses499 ,second ,edition4 ,illu/rat$4 #hvo41 clo?1 #bhg pp ,net1 #c4ej 99,,pope1 ,f4 ,l4 ,mod]n ,practice ( ! ,electric ,telegraph499 ,a ,h&book = ,electricians & ,op]ators4 ,sev5te5? ,edition4 ,illu/rat$4 #hvo41 clo?1 #bcd pp #a4ej 99,,raphael1 ,f4 ,c4 ,localization ( ,faults 9 ,electric ,light ,ma9s499 ,?ird ,edition ,9 ,press 99,,ras*1 ,e4 ,electric ,arc ,ph5om5a499 ,translat$ by ,k4 ,tornb]g4 #eb illu/rations4 #e x #g1 clo?1 #ahgpp ,net1 #b4jj 99,,raymond1 ,e4 ,b4 ,alt]nat+-,curr5t ,eng9e]+1 ,practically ,treat$499 ,?ird ,edition1 revis$4 ,) _m ,figures & ,diagrams4 #hvo41 clo?1 #bdd pp ,net1 #b4ej 99,,r$f]n1 ,t4 ,b4 & ,,sav91 ,j4 ,bells1 ,indicators1 ,telephones1 ,fire & ,burgl> ,al>ms499 #he illu/rations4 #d #a_/b x #f #c_/d1 clo?1 #abc pp4 7,in/allation ,manuals ,s]ies7 4#ej 99,,ri*>dson1 ,s4 ,s4 ,magnetism & ,electricity & ! ,pr9ciples ( ,electrical ,measurem5t499 ,illu/rat$4 #abmo41 clo?1 #eif pp4 ,net1 #b4jj 99,,rob]ts1 ,j4 ,laboratory ,"w 9 ,electrical ,eng9e]+--,prelim9>y ,grade499 ,a s]ies ( laboratory exp]im5ts = fir/ & second-ye> /ud5ts 9 electrical eng9e]+4 ,illu/rat$ ) _m ,diagrams4 #hvo41 clo?1 #bah pp ,net1 #b4jj 99,,roll9s1 ,w4 ,notes on ,x-,light499 ,pr9t$ on deckle edge ,japan pap] #djj pp4 ( text1 #aeb full-page plates4 #hvo41 clo? ,net1 #e4jj 99,,ruhm]1 ,,ern/4 ,wireless ,telephony 9 ,!ory & ,practice499 ,translat$ f ! ,g]man by ,james ,ersk9e-,murray4 ,illu/rat$4 #evo41 clo?1 #bbd pp ,net1 #c4ej 99,,russell1 ,a4 ,! ,!ory ( ,electric ,cables & ,networks499 #ga ,illu/rations4 #hvo41 clo?1 #bge pp ,net1 #c4jj 99,,say]s1 ,h4 ,m4 ,brakes = ,tramway ,c>s499 #f x #i1 clo?1 #gf pp4 ,net1 #a4be 99,,sev]1 ,g4 ,f4 ,electrical ,eng9e]+ ,exp]im5ts & ,te/s on ,direct-,curr5t ,ma*9]y499 ,second ,edition1 enl>g$4 ,) ,diagrams & ,figures4 #hvo41 pamphlet1 #ge pp ,net1 #a4jj 99,,sev]1 ,g4 ,f41 & ,,t[ns5d1 ,f4 ,laboratory & ,factory ,te/s 9 ,electrical ,eng9e]+499 ,second ,edition1 revis$ & enl>g$4 ,illu/rat$4 #hvo41 clo?1 #bfi pp ,net1 #b4ej 99,,sewall1 ,c4 ,h4 ,wireless ,telegraphy4 ,) ,diagrams & ,figures499 ,second ,edition1 correct$4 ,illu/rat$ 4 #hvo41 clo?1 #bbi pp ,net1 #b4jj - 99,lessons 9 ,telegraphy499 ,illu/rat$4 #abmo41 clo?1 #ajd pp ,net1 #a4jj 99,,sewell1 ,t ,! ,con/ruction ( ,dynamos 7,alt]nat+ & ,direct ,curr5t7499 ,a ,text-book = /ud5ts1 eng9e]+ contractors1 & electricians-9-*>ge4 ,illu/rat$4 #hvo41 clo?1 #caf pp #c4jj 99,,%eldon1 ,s41 & ,,hausmann1 ,e ,dynamo-,electric ,ma*9]y3 ,its ,con/ruction1 ,design1 & ,op]ation499 99,vol4#a43 ,direct-,curr5t ,ma*9es499 ,n9? ,edition1 completely re-writt54 ,illu/rat$4 #abmo41 clo?1 #bha pp ,net1 #b4ej 99,vol4 ,,ii43 ,alt]nat+-,curr5t ,ma*9es399 ,t5? ,edition1 rewritt54 clo?1 #cec pp ,net1 #b4ej - 99,electric ,traction & ,transmission ,eng9e]+99 #abg illu/ration4 #abmo41 clo?1 #cag pp ,net1 #b4ej 99,,sloane1 ,t4 ,o',,conor4 ,elem5t>y ,electrical ,calculations499 ,a ,manual ( ,simple ,eng9e]+ ,ma!matics1 cov]+ ! :ole field ( ,direct ,curr5t ,calculations1 ! basis ( ,alt]nat+ ,curr5t ,ma!matics1 ,networks1 & typical cases ( ,circuits1 ) ,app5dices on special subjects4 #hvo41 clo?4 ,illu/rat$4 #cjd pp ,net1 #b4jj 99,,smi?1 ,c4 ,f4 ,practical ,alt]nat+ ,curr5ts1 & ,alt]nat+ ,curr5t ,te/+499 ,?ird ,edition4 #bcf illu/rations4 #e #c_/d x #h #c_/d1 clo?1 #dgf pp4 ,net #b4fj 99,,smi?1 ,c4 ,f4 ,practical ,te/+ ( ,dynamos & ,motors499 ,?ird ,edition1 #ajh illu/rations4 #e #a_/d x #h #c_/d1 clo?1 #cbb pp ,net1 #b4jj 99,,snell1 ,,albion ,t4 ,electric ,motive ,p[]499 ,! ,transmission & ,di/ribution ( ,electric ,p[] by ,cont9u\s & ,alt]nat+ ,curr5ts4 ,) a ,section on ! ,applications ( ,electricity to ,m9+ ,"w4 ,second ,edition4 ,illu/rat$4 #hvo41 clo?1 #daa pp ,net1 #d4jj 99,,soddy1 ,f4 ,radio-,activity2 an ,elem5t>y ,treatise f ! ,/&po9t ( ! ,dis9tegration ,!ory499 ,fully ,illu/rat$4 #hvo41 clo?1 #bad pp ,net1 #c4jj 99,,solomon1 ,,maurice4 ,electric ,lamps499 ,illu/rat$4 #hvo41 clo?4 7,van ,no/r&'s ,we/m9/] ,s]ies47 ,net1 #b4jj 99,,sw9burne1 ,,jas41 & ,,word+ham1 ,c4 ,h4 ,! ,measurem5t ( ,electric ,curr5ts4 ,electrical ,measur+ ,in/rum5ts4 ,met]s = ,electrical ,en]gy499 ,edit$1 ) ,preface1 by ,t4 ,comm]=d ,m>t94 ,fold+ ,plate & ,num]\s ,illu/rations4 #afmo41 clo?1 #bda pp4 7,no4 #aji ,van ,no/r&'s ,sci5ce ,s]ies47 #ej c5ts 99,,swoope1 ,c4 ,,walton4 ,lessons 9 ,practical ,electricity3 ,pr9ciple ,exp]im5ts1 & ,ari?metical ,problems4 ,an ,elem5t>y ,textbook499 ,) num]\s ,tables1 ,=mulae1 & two l>ge ,in/ruction ,plates4 ,fifte5? ,edition1 revis$4 ,illu/rat$4 #evo41 clo?1 #dfb pp ,net1 #b4jj 99,,?iess1 ,j4 ,b4 & ,,joy1 ,g4 ,a4 ,toll ,telephone ,practice499 #bgc illu/rations4 #hvo41 clo?1 #dcc pp ,net1 #c4ej 99,,?om1 ,c41 & ,,jones1 ,w4 ,h4 ,telegraphic ,connections1 embrac+ rec5t me?ods 9 ,quadruplex ,telegraphy499 #bj ,color$ ,plates4 #hvo41 clo?1 #ei pp #a4ej 99,,?ompson1 ,s4 ,p41 ,pr(4 ,dynamo-,electric ,ma*9]y499 ,) an ,introduction & ,notes by ,frank ,l4 ,pope & ,h4 ,r4 ,butl]4 ,illu/rat$ #afvo41 clo?1 #bad pp4 7,no4 #ff ,van ,no/r&'s ,sci5ce ,s]ies47 #ej c5ts - 99,rec5t ,progress 9 ,dynamo-,electric ,ma*9es499 ,be+ a ,supplem5t to ,dynamo-,electric ,ma*9]y4 ,illu/rat$4 #afmo41 clo?1 #aac pp4 7,no4 #ge ,van ,no/r&'s ,sci5ce ,s]ies47 #ej c5ts 99,,t[ns5d1 ,,fitzhugh4 ,alt]nat+ ,curr5t ,eng9e]+499 ,illu/rat$4 #hvo1 pap]1 #cb pp ,net1 #ge c5ts 99,,und]bill1 ,c4 ,r4 ,sol5oids1 ,electromagnets & ,electromagnetic ,w9d+s499 ,second ,edition4 #bah ,illu/rations4 #abmo41 clo?1 #cde pp ,net1 #b4jj 99,,urquh>t1 ,j4 ,w4 ,electroplat+499 ,fif? ,edition4 ,illu/rat$4 #abmo41 clo?1 #bcj pp #b4jj - 99,electrotyp+499 ,illu/rat$4 #abmo41 clo?1 #bbh pp #b4jj 99,,vosma]1 ,a4 ,ozone499 ,its ,manufacture & ,uses4 #gf illu/rations4 #f x #i1 clo?1 #baj pp ,net1 #b4ej 99,,wade1 ,e4 ,j4 ,second>y ,batt]ies3 ,_! ,!ory1 ,con/ruction1 & ,use499 ,second ,edition1 correct$ #bfe illu/rations4 #hvo41 clo?1 #eja pp4 ,net1 #d4jj 99,,wadswor?1 ,c4 ,prim>y ,batt]y ,ignition499 ,a simple practical pocket guide on ! con/ruction1 op]ation1 ma9t5ance1 & te/+ ( prim>y batt]ies = automobile1 motorboat1 & /ation>y eng9e ignition s]vice4 #bf illu/rations4 #e x #g1 clo?1 #gi pp ,net1 #j4ej 99,,walk]1 ,,fr$]ick4 ,practical ,dynamo ,build+ = ,amateurs4 ,h[ to ,w9d = any ,output499 ,?ird ,edition4 ,illu/rat$4 #afmo41 clo?1 #ajd pp4 7,no4 #fh ,van ,no/r&'s ,sci5ce ,s]ies47 #ej c5ts4 - 99,electricity 9 ,m9+499 ,illu/rat$4 #hvo41 clo?1 #che pp 4#ej 99,,watt1 ,,alex&]4 ,electroplat+ & ,ref9+ ( ,metals99 ,new ,edition1 rewritt5 by ,arnold ,philip4 ,illu/rat$ #hvo41 clo?1 #gjd pp ,net1 #d4ej - 99,electro-metallurgy99 ,fifte5? ,edition4 ,illu/rat$ #abmo41 clo?1 #bbe pp #a4jj 99,,webb1 ,h4 ,l4 ,a ,practical ,guide to ! ,te/+ ( ,insulat$ ,wires & ,cables99 ,six? ,edition4 ,illu/rat$4 #abmo41 clo?41 #aahpp #a4jj 99,,wilk9son1 ,h4 ,d4 ,subm>9e ,cable-,lay+1 ,repair+1 & ,te/+499 ,second ,edition1 completely revis$4 #cac illu/rations4 #hvo41 clo?1 #ehj pp ,net1 #f4jj 99,,wilson1 ,j4 ,f4 ,ess5tials ( ,electrical ,eng9e]+499 #cjj illu/rations4 #f x #i1 clo?1 #cee pp ,net1 #b4ej 99,,wright1 ,j4 ,te/+1 ,fault ,localization & ,g5]al ,h9ts = ,l9em5499 #ai ,illu/rations4 #afmo41 clo?1 #hh pp4 7,in/allation ,s]i\s ,manuals47 ,net1 #ej c5ts4 99,,"y1 ,j4 ,,elton4 ,electrical ,te/+ = ,telegraph ,eng9e]s499 ,illu/rat$4 #hvo41 clo?1 #bfd pp ,net1 #d4jj 99,,zeidl]1 ,j41 & ,,lu/g>t51 ,j4 ,electric ,arc ,lamps3 ,_! ,pr9ciples1 ,con/ruction & ,work+499 #afj ,illu/rations4 #hvo41 clo?1 #ahh pp ,net1 #b4jj ,a #if page ,catalog ( ,books on ,electricity1 classifi$ by subjects1 w be furni%$ gratis1 po/age prepaid1 on application4 ,d4 ,,van ,,no/r& ,,company are prep>$ to supply1 ei!r f _! complete /ock or at %ort notice1 ,any ,te*nical or ,sci5tific ,book ,9 addition to publi%+ a v l>ge & v>i$ numb] ( ,,sci5tific ,,& ,,eng9e]+ ,,books1 ,d4 ,van ,no/r& ,company h on h& ! l>ge/ assortm5t 9 ! ,unit$ ,/ates ( su* books issu$ by ,am]ican & =eign publi%]s4 ,all inquiries are *e]fully & c>efully answ]$ & complete catalogs s5t free on reque/4 #be ,,p>k ,,place - - ,,new ,,york