,transcrib]'s ,notes3 #a4 ,subscripts h be5 m>k$ ) an und]score "* 9 front ) text surr\nd$ 9 curly braces1 = example3 ,h#b,o 7=mula ( wat]74 #b4 ,inconsi/5t hyph5ation ( words pres]v$4 #c4 ,sev]al mispr9ts fix$4 ,a full li/ ( corrections c be f\nd at ! end ( ! text4 ,illu/ration3 ,,light ,,& ,,lib]ty ,! ,c5tury ,books ( ,useful ,sci5ce ,,artificial ,,light ,,its ,,influ5ce ,,^u ,,civilization ,,by ,m4 ,,luckie% ,,director ,,( ,,appli$ ,,sci5ce4 ,,nela ,,rese>* ,,laboratory1 ,,national ,,lamp ,,works ,,( ,,g5]al ,,electric ,,company ,au?or ( ,color & ,its ,applications1 ,light & ,%ade & ,_! ,applications1 ,! ,light+ ,art1 ,! ,language ( ,color1 etc4 ,,illu/rat$ ,,) ,,photographs ,,new ,,york ,,! ,,c5tury ,,co4 #aibj ,copyright1 #aibj1 by ,,! ,,c5tury ,,co4 ,,d$icat$ ,,to ,,^? ,,:o ,,h ,,enc\rag$ ,,organiz$ ,,sci5tific ,,rese>* ,,= ,,! ,,advancem5t ,,( ,,civilization ,,preface ,9 ! foll[+ pages ,i h endeavor$ to discuss artificial light = ! g5]al read]1 9 a mann] z devoid z possible ( intricate details4 ,! e>ly *apt]s deal p>ticul>ly ) primitive artificial light & _! cont5ts are g5]ally hi/orical4 ,! sci5ce ( light-production may be consid]$ to h be5 born 9 ! latt] "p ( ! eighte5? c5tury & beg9n+ ) t p]iod a few *apt]s treat ( ! developm5t ( artificial light up to ! pres5t "t4 ,until ! middle ( ! n9ete5? c5tury m]e light 0 available1 b z ! c5tury progress$1 ! light-s\rces ?r\gh ! application ( sci5ce became m p[]ful & effici5t4 ,gradually m]e light grew to m light & 9 ! dawn ( ! tw5tie? c5tury adequate light became available4 ,9 a s+le c5tury1 aft] ! developm5t ( artificial light began 9 e>ne/1 ! effici5cy ( light-production increas$ fifty-fold & ! co/ dim9i%$ correspond+ly4 ,! next gr\p ( *apt]s deals ) v>i\s economic influ5ces ( artificial light & ) "s ( ! byways 9 :i* artificial light is s]v+ mank9d4 ,on pass+ ?r\gh ! spectacul> aspects ( light+ we f9ally em]ge into ! e/hetics ( light & light+4 ,! aim has be5 to %[ t artificial light has become intricately int]wov5 ) human activities & t x has be5 a p[]ful influ5ce ^u ! progress ( civilization4 ,! subject is too ext5sive to be treat$ 9 detail 9 a s+le volume1 b an ef=t has be5 made to pres5t a discussion fairly complete 9 scope4 ,x is hop$ t ! read] w ga9 a great] appreciation ( artificial light z an economic factor1 z an arti/ic m$ium1 & z a mighty influ5ce ^u ! safety1 effici5cy1 heal?1 happ9ess1 & g5]al progress ( mank9d4 ,m4 ,,luckie%4 ,,ackn[l$gm5ts ,x is a pleasant duty to ackn[l$ge ! cop]ation ( v>i\s companies 9 obta9+ ! photographs :i* illu/rate ?is book4 ,) ! exception ( ,plates #b & #g1 :i* are reproduc$ f ! excell5t works ( ,b5es* & ,allegemane respectively1 ! illu/rations ( e>ly light+ devices are tak5 f an hi/orical collection 9 ! possession ( ! ,national ,lamp ,works ( ! ,g5]al ,electric ,co4 ,to ?is company ! au?or is indebt$ = ,plates #a1 #c1 #d1 #e1 #f1 #i1 #aa1 #ae1 #ah;b1 #bj1 #ba1 #bi2 to ,dr4 ,mc,farlan ,moore = ,plate #aj2 to ,macbe? ,evans ,glass ,co4 = ,plate #ab2 to ! ,corps ( ,eng9e]s1 ,u4 ,s4 ,army1 = ,plate #ac2 to ,lynn ,works ( ,g4 ,e4 ,co4 = ,plates #ad1 #af2 to ,edison ,lamp ,works ( ,g4 ,e4 ,co4 = ,plates #ag1 #bd2 to ,coop] ,hewitt ,co4 = ,plate #ah;a2 to ,r4 ,u4 ,v4 ,co4 = ,plate #ai2 to ,new ,york ,edison ,co4 = ,plates #bb1 #bf1 #cj2 to ,w4 ,d',a4 ,ryan & ! ,s*5ectady ,works ( ,g4 ,e4 ,co4 = ,plates #bc1 #be1 #ca2 to ,national ,x-,ray ,reflector ,co4 = ,plate #bh4 ,besides ! companies & ! individuals p>ticul>ly involv$ 9 ! =ego+1 ! au?or is glad to ackn[l$ge 8 appreciation ( ! assi/ance ( o!rs dur+ ! prep>ation ( ?is volume4 ,,cont5ts ,,*apt] ,,page ,i ,,light ,,& ,,progress #c ,,ii ,,! ,,art ,,( ,,mak+ ,,fire #ae ,,iii ,,primitive ,,light-,,s\rces #bd ,,iv ,,! ,,c]emonial ,,use ,,( ,,light #ch ,v ,,oil-,,lamps ,,( ,,! ,,n9ete5? ,,c5tury #ea ,,vi ,,e>ly ,,gas-,,light+ #fc ,,vii ,,! ,,sci5ce ,,( ,,light-,,production #hj ,,viii ,,mod]n ,,gas-,,light+ #ig ,,ix ,,! ,,electric ,,arcs #aaa ,x ,,! ,,electric ,,inc&esc5t ,,filam5t ,,lamps #abg ,,xi ,,! ,,light ,,( ,,! ,,future #adc ,,xii ,,light+ ,,! ,,/reets #aeb ,,xiii ,,ligh?\ses #afc ,,xiv ,,artificial ,,light ,,9 ,,w>f>e #agh ,,xv ,,signal+ #aid ,,xvi ,,! ,,co/ ,,( ,,light #bjh ,,xvii ,,light ,,& ,,safety #bbe ,,xviii ,,! ,,co/ ,,( ,,liv+ #bch ,,xix ,,artificial ,,light ,,& ,,*emi/ry #bef ,,xx ,,light ,,& ,,heal? #bfi ,,xxi ,,modify+ ,,artificial ,,light #bhd ,,xxii ,,spectacul> ,,light+ #bih ,,xxiii ,,! ,,expressiv5ess ,,( ,,light #caj ,,xxiv ,,light+ ,,! ,,home #cbe ,,xxv ,,light+--,a ,,f9e ,,art8 #cda ,,read+ ,,ref]5ces #ceg ,,index #cei ,,li/ ,,( ,,illu/rations ,light & ,lib]ty ,frontispiece ,,fac+ ,,page ,primitive fire-baskets #af ,crude spl9t]-hold]s #af ,e>ly op5-flame oil & grease lamps #ag ,a typical metal multiple-wick op5-flame oil-lamp #cb ,a gr\p ( oil-lamps ( two c5turies ago #cc ,lamps ( a c5tury or two ago #ef ,elaborate fixtures ( ! age ( c&les #eg ,flame arc #abh ,direct curr5t arc #abh ,on ! te/+-racks ( ! manufactur] ( inc&esc5t filam5t lamps #abi ,c>bon-dioxide tube = accurate color-mat*+ #afj ,! ,moore nitrog5 tube #afj ,mod]n /reet light+ #afa ,a complet$ ligh?\se l5s #agf ,torro ,po9t ,ligh?\se1 ,panama ,canal #agf ,am]ican se>*-light position on ,we/]n ,front 9 #aiai #agg ,am]ican /&>d field se>*-light & p[] unit #agg ,signal-light = airplane #bcb ,tr5* light-signal+ outfit #bcb ,aviation field light-signal projector #bcb ,signal se>*-light = airplane #bcb ,unsafe1 unproductive light+ wor?y ( ! d>k ages #bcc ,! same factory made safe1 *e]ful1 & m productive by mod]n light+ #bcc ,locomotive electric headlight #bdj ,se>*-light on a fire-boat #bdj ,build+ %ips "u artificial light at ,hog ,isl& ,%ipy>d #bda ,artificial light 9 photography #bef ,/]iliz+ wat] ) radiant en]gy f qu>tz m]cury-arcs #beg ,judg+ color "u artificial daylight #bgb ,artificial daylight #bgc ,fireworks & illum9at$ battle-fleet at ,hudson-,fulton ,celebration #bhh ,fireworks exhibition on ,may ,day at ,panama-,pacific ,exposition #bhi ,! new flood light+ contra/$ ) ! old outl9e light+ #cjd ,niag>a ,falls flood$ ) light #cje ,artificial light honor+ ^? :o fell & ^? :o return$ #cbj ,! expressiv5ess ( light 9 *ur*es #cba ,obta9+ two diff]5t moods 9 a room by a portable lamp :i* supplies direct & indirect compon5ts ( light #ccf ,! lights ( ,new ,york ,city #ccg ,artificial light 9 community affairs #ceb ,panama-,pacific ,exposition #cec ,,artificial ,,light ,i ,,light ,,& ,,progress ,! human race 0 born 9 slav]y1 totally subs]vi5t to nature4 ,! e>lie/ primitive be+s fea/$ or />v$ accord+ to nature's b\nty & swelt]$ or %iv]$ accord+ to ! wea!r4 ,:5 night fell !y s\ght %elt] ) animal in/9ct1 = n only 7 activities almo/ completely curtail$ by d>kness b beyond its scre5 lurk$ _m dang]s4 ,x is int]e/+ to philosophize ^u a di/9ction betwe5 a human be+ & ! animal j bel[ him 9 ! scale1 b x may s]ve ! pres5t purpose to di/+ui% ! human be+ z t animal 9 :om !re is an unqu5*able & insatiable desire = indep5d5ce4 ,! ef=t to escape f ! bondage ( nature is n solely a human in/9ct2 animals burr[ or build retreats ?r\gh ! in/9ct ( self-pres]vation4 ,b ?is in/9ct 9 animals is soon satisfi$1 :]eas 9 human be+s x has be5 lead+ ev] onw>d t[>d complete emancipation4 ,! progress ( civilization is a long *a9 ( c\ntless a*ievem5ts ea* "o ( :i* has increas$ man's indep5d5ce4 ,e>ly man p]haps did n conceive ! idea ( fire & !n set out to produce x4 ,8 infant m9d did n op]ate 9 ?is mann]4 ,b :5 he accid5tally /ruck a sp>k1 produc$ fire by friction1 or discov]$ x 9 "s o!r mann]1 he saw its possibility4 ,x is ?rill+ to picture primitive man at 8 fir/ bonfire1 enjoy+ ! w>m?1 or at lea/ int]e/$ 9 x4 ,b h[ wond]ful x mu/ h become z twilight's curta9 0 drawn across ! heav5s6 ,?is controllable fire emitt$ light4 ,x is easy to imag9e primitive man pond]+ ov] ?is ph5om5on ) 8 sluggi% m9d4 ,d\btless he cauti\sly pick$ up a flam+ /ick & timidly explor$ ! cr[d+ d>kness4 ,p]haps he c>ri$ x into 8 cave & behold6 night _h retreat$ f 8 abode6 ,no long] 0 x necess>y = him to retire to 8 b$ ( leaves :5 daylight fail$4 ,! fire n only bani%$ ! *ill ( night b 0 a p[] ov] d>kness4 ,view$ f ! /&po9t ( civilization1 its discov]y 0 "o ( ! greate/ /rides along ! highway ( human progress4 ,! activities ( man 7 no long] b\nd$ by sunrise & sunset4 ,! m>* ( civilization _h begun4 ,9 ! pres5t age ( abundant artificial light1 ) its manifold light-s\rces & accessories :i* h made possible c\ntless applications ( light1 mank9d does n realize ! importance ( ?is com=t4 ,its wond]ful conv5i5ce & omnipres5ce h result$ 9 indiff]5ce t[>d x by mank9d 9 g5]al1 not)/&+ ! fact t x is ess5tial to man's mo/ important & educative s5se4 ,by ext+ui%+ ! light & pond]+ ^u 8 helplessness 9 ! result+ d>kness1 man may ga9 an idea ( its ov]:elm+ importance4 ,^? un=tunate p]sons :o suff] ! t]rible calamity ( bl9dness aft] ye>s ( dep5d5ce ^u sight w te/ify 9 he>tr5d+ t]ms to ! importance ( light4 ,milton1 ^: eyesight _h fail$1 lam5ts1 ,o fir/ creat$ beam & ?\ great ,^w ,let !re be light1 & light 0 ov] all1 ,:y am ,i ?us b]eav$ ?y prime decree8 ,p]haps only ?r\gh a simil> loss w\ld "o fully appreciate ! trem5d\s importance ( light to him1 b imag9ation %\ld be capable ( conv9c+ him t x is "o ( ! mo/ ess5tial & pleasure-giv+ ph5om5a kn[n to mank9d4 ,a retrospective view d[n ! vi/a ( c5turies reveals by contra/ ! complexity ) :i* artificial light is wov5 into human activities ( ! pres5t "t4 ,writt5 hi/ory fails long be=e ! primitive races are rea*$1 b x is safe to tru/ ! imag9ation to p5etrate ! fog ( unwritt5 hi/ory & f9d e>ly man huddl$ 9 8 cave z daylight wanes4 ,impell$ by ! re/less _s ( progress1 ?is primitive be+ grasp$ ! opportunity :i* fire af=d$ to ext5d 8 activities beyond ! b\nd>ies ( daylight4 ,! crude art ^u ! walls ( 8 cave 0 execut$ by ! flame ( a smok+ fagot4 ,! fire on ! l$ge at ! entrance to 8 abode became a symbol ( home1 z ! fire on ! he>? has symboliz$ home & hospitality ?r\gh\t succe$+ ages4 ,! accompany+ light & ! protection f cold comb9$ to e/abli% ! home circle4 ,! ties ( mat$ animals exp&$ ?r\gh ^! influ5ces to ! bonds ( family4 ,?us light 0 wov5 e>ly into family life & has be5 ?r\gh\t ! ages a moraliz+ & civiliz+ influ5ce4 ,to-day ! resid5ce functions z a home ma9ly "u artificial light1 = ow+ to ! conditions ( liv+ & work+1 ! family gr\p ga!rs *iefly aft] daylight has fail$4 ,f ! p9e knot ( primitive man to ! wond]fully conv5i5t light-s\rces ( to-day !re is a great int]val1 consi/+1 z appe>s retrospectively1 ( small & simple /eps long p]iods ap>t4 ,measur$ by pres5t /&>ds & a*ievem5ts1 developm5t 0 sl[ at fir/ & mod]n man may be incl9$ to impati5ce z he views ! hi/ory ( light & human progress4 ,b ! a*ievem5ts ( e>ly c5turies1 :i* appe> s simple at ! pres5t "t1 7 really great accompli%m5ts :5 consid]$ 9 ! light ( ! k ( ^? remote p]iods4 ,sci5ce z x exi/s to-day is f\nd$ ^u prov$ facts4 ,! sci5ti/1 equipp$ ) a k ( physical & *emical laws1 is l$ by 8 imag9ation into ! d>kness ( ! unexplor$ unkn[n4 ,?is k illum9ates ! pa?way s t hypo!ses are intellig5tly =m$4 ,^! evolve into !ories :i* are gradually alt]$ to fit ! accumulat+ facts1 = along ! battle area ( progress !re are innum]able sc\t+-p>ties ga9+ secrets f nature4 ,^! are support$ by individuals & by gr\ps1 :o v]ify1 amplify1 & organize ! facts1 & !y 9 turn are foll[$ by inv5tors :o apply !m4 ,liaison is ma9ta9$ at all po9ts1 b ! attack v>ies f "t to "t4 ,x may be int5se at c]ta9 places & o!r sectors may be quiet = a "t4 ,!re are occasional rev]ses1 b ! :ole l9e 9 g5]al progresses4 ,ea* ye> witnesses ! acquirem5t ( new t]ritory4 ,x is se5 t ?r\gh ! c5turies !re is an ev]-gr[+ mom5tum z k1 effici5cy1 & organization increase ! /r5g? ( ?is invad+ army ( sci5ti/s & inv5tors4 ,! burn+ fagot rescu$ mank9d f ! %ackles ( d>kness1 & ! grease-lamp & tall[-c&le h done _! "p4 ,progress 0 sl[ 9 ^? e>ly c5turies because ! great m9ds ( ^? ages philosophiz$ )\t a basis ( e/abli%$ facts3 sci5tific progress result$ m f an accumulation ( accid5tal discov]ies ?an by a direct$ attack ( philosophy support$ by ! facts e/abli%$ by exp]im5t4 ,x 0 n until comp>atively rec5t times1 at mo/ ?ree c5turies ago1 t ! great intellects turn$ to sy/ematically organiz$ sci5tific rese>*4 ,su* m5 z ,newton laid ! f\ndation = ! trem5d\s /rides ( to-day4 ,! /ore ( facts increas$ & z ! attitude *ang$ f philosophiz+ to inve/igat+1 ! organiz$ k grew apace4 ,all ( ?is pav$ ! way = ! mom5t\s successes ( ! pres5t "t4 ,! end is n 9 sight & p]haps nev] w be4 ,! unexplor$ region ext5ds to inf9ity &1 judg$ by ! pa/1 ! mom5tum ( discov]y w cont9ue to increase = ages to come1 unless ! human race decays ?r\gh ! com=t & ease ga9$ f utiliz+ ! magic secrets :i* are con/antly be+ wre/$ f nature4 ,among ! a*ievem5ts ( sci5ce & inv5tion1 ! production & application ( artificial light ranks high4 ,z an influ5ce ^u civilization1 no s+le a*ievem5t surpasses x4 ,)\t artificial light1 mank9d w\ld be comp>atively inactive ab\t "o half its lifetime4 ,to-day x has be5 fairly well e/abli%$ t ! human organism c fl\ri% on eight h\rs' sleep 9 a p]iod ( tw5ty-f\r h\rs4 ,ano!r eight h\rs sp5t 9 "w %\ld settle man's obligation to ! _w4 ,! rema9+ h\rs %\ld be 8 own4 ,artificial light has made su* a di/ribution ( "t possible4 ,! work+-p]iods 9 _m cases may be arrang$ 9 ! int]e/s ( economy1 :i* (t5 means cont9u\s op]ations4 ,! sun ne$ n be consid]$ :5 ^! op]ations are conf9$ to int]iors or localiz$ outdoors4 ,?us1 artificial light has be5 an important factor 9 ! great indu/rial developm5t ( ! pres5t "t4 ,man n[ burr[s into ! e>?1 navigates "u wat]1 travels ^u ! surface ( l& & sea1 & so>s among ! cl\ds pilot$ by light ( 8 own mak+4 ,progress does n halt at sunset b cont9ues tw5ty-f\r h\rs ea* day4 ,build+1 pr9t+1 manufactur+1 comm]ce1 & o!r activities are prosecut$ cont9u\sly1 ! work+-%ifts *ang+ at c]ta9 p]iods reg>dless ( ! ris+ or sett+ sun4 ,adequate artificial light+ decreases spoilage1 increases production1 & is a p[]ful factor 9 ! prev5tion ( indu/rial accid5ts4 ,x has ev] be5 true s9ce ! adv5t ( artificial light t ! intellect has be5 l>gely n\ri%$ aft] ! completion ( ! day's "w4 ,! highly develop$ artificial light+ ( ! pres5t "t may acc\nt = mu* ( ! va/ indu/ry ( publication4 ,books1 magaz9es1 & newspap]s owe mu* to conv5i5t & inexp5sive artificial light1 = )\t x few] h\rs w\ld be available = recreation & advancem5t ?r\gh read+4 ,s*ools1 libr>ies1 & art museums may be att5d$ at night = ! bett]m5t ( ! human race4 ,! immortal ,l9coln1 x is said1 ga9$ 8 e>ly education l>gely by ! light ( ! fireplace4 ,b all 7 n end[$ ) ! p]si/5ce ( ,l9coln1 s t illit]acy 0 m common 9 8 day ?an 9 ! pres5t age ( adequate illum9ation4 ,! !atrical /age n only dep5ds = its effectiv5ess ^u artificial light b owes its exi/5ce & developm5t l>gely to ?is ag5cy4 ,9 ! mov+-picture !at]1 pictures are project$ ^u ! scre5 by means ( x & ev5 ! production ( ! pictures is indep5d5t ( daylight4 ,^! & a va/ numb] ( recreational activities owe mu*1 & 9 "s cases _! exi/5ce1 to artificial light4 ,n _m c5turies ago ! /reets at night 7 ov]run by ?ieves & to v5ture outdoors aft] d>k 0 to c\rt robb]y & ev5 bodily h>m4 ,9 ^! days ( comp>ative safety x is difficult to realize ! influ5ce t abundant illum9ation has _h 9 increas+ ! safety ( life & prop]ty4 ,maet]l9ck 9 8 poetical drama1 ,! ,bluebird1 appropriately has made ,light ! fai?ful companion ( mank9d4 ,! ,palace ( ,night1 into :i* ,light is n p]mitt$ to ent]1 is ! abode ( _m evils4 ,?us ! poet has play$ ^u ! primitive in/9cts ( ! impressiv5ess ( light & d>kness4 ,by comb9+ ! symbolism ( light1 color1 & d>kness ) ! in/9cts :i* h be5 inh]it$ by mank9d f its sup]/iti\s ance/ry ( ! age ( my?ology1 ano!r field ( application ( artificial light is op5$4 ,light has gradually assum$ su* attributes z tru?1 k1 progress1 enlight5m5t4 ,?r\gh\t ! e>ly ages light 0 m or less wor%ip$ & ?us artificial lights became wov5 9 _m religi\s c]emonies4 ,"s ( ^! h p]si/$ to ! pres5t "t4 ,! great pageants ( peace celebrations & _w's expositions appropriately feature artificial light4 ,9 draw+ ^u ! pot5tiality ( ! expressiv5ess & impressiv5ess ( light & color1 artificial light is play+ a major "p4 ,d\btless ! future g5]ations w be ent]ta9$ by gorge\s symphonies ( light4 ,exp]im5ts are p]=m$ 9 ?is direction n[ & !n1 & x is reasonable to expect t aft] _m c5turies ( cultivation ( ! appreciation ( light-symphonies1 ^! w take a place among ! arts4 ,! elaborate & complicat$ music ( ! pres5t "t is appreciat$ by civiliz$ nations only aft] _m c5turies ( sl[ cultivation ( ta/e & und]/&+4 ,light-!rapy is to-day a di/9ct sci5ce & art4 ,! g]micidal action ( light-rays & ( "s ( ! invisible rays :i* ord9>ily accompany ! lum9\s rays is well prov$4 ,w\nds are treat$ effectively & wat] is /]iliz$ by ! ultraviolet radiant en]gy 9 mod]n artificial illum9ants4 ,?\s&s ( ligh?\ses1 light-%ips1 & light-buoys are scatt]$ along sea-coa/s1 riv]s1 & *annels4 ,!y guide ! :eelman & w>n ! look\t ( %oals & reefs4 ,"s ( ^! s5d =? fla%es ( light ^: int5sities are measur$ 9 millions ( c&le-p[]4 ,_m are unatt5d$ = days & ev5 mon?s4 ,^! p[]ful lights dom9at$ by automatic me*anisms h replac$ ! wood-fires :i* 7 ma9ta9$ a few c5turies ago ^u c]ta9 prom95t po9ts4 ,signal-lights n[ guide ! railroad tra9 ?r\gh ! night4 ,a burn+ fl>e dropp$ f ! re> ( a tra9 keeps ! foll[+ tra9 at a safe di/ance4 ,huge se>*-lights p5etrate ! night air = _m miles4 ,:5 ^! are equipp$ ) %utt]s1 a code may be fla%$ f "o %ip to ano!r or betwe5 ! vessel & l&4 ,a code f a p[]ful se>*-light has be5 read a hundr$ miles away because ! fla%es 7 project$ ^u a lay] ( high cl\ds & 7 ?us visible f> beyond ! horizon4 ,artificial light play$ its "p 9 ! rec5t w>4 ,huge se>*-light equipm5ts 7 devis$ = portability4 ,?is mobile app>atus 0 utiliz$ aga9/ enemy aircraft & 9 v>i\s o!r ways4 ,small h&-lamps are us$ to s5d out a p5cil ( light z direct$ by a pair ( sights & ! code is fla%$ by means ( a trigg]4 ,raid+-p>ties are no long] conceal$ by ! curta9 ( d>kness1 = rockets & />-%ells are us$ to illum9ate l>ge areas4 ,fl>es s5t upw>d to drift sl[ly d[nw>d support$ by p>a*utes sav$ & co/ _m lives dur+ ! rec5t w>4 ,rockets are us$ by %ips 9 di/ress & also by beleagu]$ troops4 ,exp]im5ts are be+ prosecut$ to asc]ta9 ! possibilities ( artificial light 9 ! =c+ ( plant-gr[?1 & ev5 *ick5s are made to "w long] h\rs by its use4 ,artificial light is n[ modifi$ 9 color or spectral "* to meet _m requirem5ts4 ,daylight has be5 reproduc$ 9 spectral quality s t c]ta9 processes requir+ accurate discrim9ation ( color are n[ prosecut$ tw5ty-f\r h\rs a day "u artificial daylight4 ,color$ light is made ( ! correct quality :i* does n affect photographic plates ( v>i\s s5sibilities4 ,mono*romatic light is utiliz$ 9 photo-micrography = ! be/ r5dition ( detail4 ,light-waves h be5 utiliz$ z /&>ds ( l5g? because !y are inv>iable & fundam5tal4 ,num]\s o!r int]e/+ adaptations ( artificial light are 9 daily use4 ,?is is 9 reality ! age ( artificial light1 = mank9d has n only become indep5d5t ( daylight 9 c]ta9 respects1 b has improv$ ^u natural light4 ,! controllability ( artificial light makes x sup]ior to natural light 9 _m ways4 ,9 fact1 uses h be5 made ( artificial light :i* are impossible ) natural light4 ,light-s\rces may be made ( a va/ v>iety ( %apes1 & ^? may be transport$ :]ev] desir$4 ,!y may be equipp$ ) reflectors & o!r optical devices to direct or to diffuse ! light z requir$4 ,?us1 artificial light to-day has num]\s advantages ov] light :i* has be5 furni%$ by ! ,creator4 ,x is sometimes /at$ t x c nev] compete ) daylight 9 *eapness1 inasmu* z ! latt] co/s no?+4 ,b ?is is n true4 ,ev5 9 ! resid5ce1 daylight co/s some?+1 because w9d[s are m exp5sive ?an pla9 walls4 ,! exp5se ( wa%+ w9d[s is an appreciable p]c5tage ( ! co/ ( gas or electricity4 ,& !re is w9d[-breakage to be consid]$4 ,9 ! m elaborate build+s ( ! conge/$ portions ( cities1 daylight is satisfactory a less] numb] ( h\rs ?an 9 ! outly+ di/ricts4 ,9 "s /ores1 (fices1 & factories artificial light is us$ ?r\gh\t ! day4 ,/ill1 ! daylight+-equipm5t is in/all$ & ma9ta9$4 ,fur!rmore1 :5 x is consid]$ t mu* exp5sive area is giv5 to light-c\rts & mu* valuable wall space to w9d[s1 x is se5 t ! co/ ( daylight 9 conge/$ cities is 9 reality consid]able4 ,( c\rse1 ! daylight+-equipm5t has value 9 v5tilat+1 b v5tilation may be tak5 c>e ( 9 a v satisfactory mann] z a sep>ate problem4 ,! co/ ( skylights 9 museums & o!r l>ge build+s is f> great] ?an t ( ord9>y ceil+s & walls1 & ! extra all[ance = heat+ is appreciable4 ,! exp5se ( ma9t5ance ( "s skylights is consid]able4 ,?us x is se5 t ! co/ & ma9t5ance ( daylight+-equipm5t1 ! loss ( valuable r5tal space & ( wall area1 & ! increas$ exp5se ( heat+ are factors :i* *all5ge ! /atem5t t daylight co/s no?+4 ,9 fact1 x is n surpris+ to f9d t occasionally ! elim9ation ( daylight+--! reliance ^u artificial light alone--has be5 s]i\sly contemplat$4 ,:5 ! possibilities ( ! latt] are consid]$1 x is reasonable to expect t x w make great] & great] inroads & t _m build+s ( ! future w be equipp$ solely ) artificial-light+ sy/ems4 ,naturally1 ) ! trem5d\s developm5t ( artificial light dur+ ! pres5t age1 a new pr(ession has aris54 ,! light+ exp]t is evolv+ to fill ! ne$s4 ,he is /udy+ ! problems ( produc+ & utiliz+ artificial illum9ation4 ,he deals ) ! physics ( light-production4 ,8 /udies ( utilization c>ry him into ! va/ fields ( physiology & psy*ology4 ,8 is a pr(ession :i* ev5tually w lead into num]\s highways & byways ( ent]prise1 because ! possibilities ( light+ ext5d into all ^? activities :i* make _! appeal to consci\sness ?r\gh ! doorway ( vision4 ,^! possibilities are limit$ only by ! b\nd>ies ( human endeavor & 9 ! broade/ s5se ext5d ev5 beyond !m1 = light is "o ( ! mo/ prom95t ag5cies 9 ! s*eme ( creation4 ,x contributes l>gely to ! safety1 ! effici5cy1 & ! happ9ess ( civiliz$ be+s & beyond all x is a p[]ful civiliz+ ag5cy4 ,,ii ,,! ,,art ,,( ,,mak+ ,,fire ,scatt]$ ov] ! e>? at ! pres5t "t v>i\s /ages ( civilization are to be f\nd1 f ! primitive savages to ! mo/ highly cultivat$ peoples4 ,al?\gh x is possible t !re are tribes ( l[ly be+s on e>? to-day unfamili> ) fire or ignorant ( its uses1 savages are g5]ally able to make fire4 ,?us ! use ( fire may s]ve ! purpose ( di/+ui%+ human be+s f ! l[] animals4 ,surely ! savage ( to-day :o is unable to k9dle fire or :o possesses a m9d z yet insuffici5tly develop$ to realize its possibilities1 is q at ! m]cy ( nature's :ims4 ,he lives m]ely by animal pr[ess & diff]s little 9 de$s & ne$s f ! bea/s ( ! jungle4 ,9 ?is imag9>y j\rney to ! remote regions beyond ! outskirts ( civilization x soon becomes evid5t t ! developm5t ( artificial light may be a fair measure ( civilization4 ,9 view+ ! developm5t ( artificial light x is se5 t prec$+ ! mod]n electrical age1 man dep5d$ univ]sally ^u burn+ mat]ial4 ,obvi\sly1 ! c\rse ( civilization has be5 highly complex & _c be symboliz$ adequately by ! bran*+ tree4 ,f its obscure beg9n+ f> 9 ! imp5etrable fog ( prehi/oric times1 x has bran*$ "h & !re4 ,^! v>i\s bran*es h be5 subject$ to _m diff]5t influ5ces1 ) ! result t "s fl\ri%$ & endur$1 "s retrogress$1 "s di$1 "s w5t to se$ & fell to take root & to beg9 aga9 ! upw>d climb4 ,! ultimate result is ! v>i$ civilization ( ! pres5t "t1 a /udy ( :i* aids 9 p5etrat+ ! veil t obscures ! ages ( unrecord$ writ+4 ,likewise1 mat]ial relics ( bygone ages supply "s ?reads ( ! /ory ( human progress & my?ology aids 9 spann+ ! mi/y gap betwe5 ! e>lie/ ages ( man & ! p]iod :5 hi/oric writ+s 7 begun4 ,?r\gh\t ^! v>i\s /ages x becomes manife/ t ! developm5t ( artificial light is associat$ ) ! progress ( mank9d4 ,accord+ to a c]ta9 my?1 ,prome!us /ole fire f heav5 & br\ght ?is bless+ to e>?4 ,?r\gh\t ! my?ologies ( v>i\s races1 fire &1 z a consequ5ce1 light h be5 associat$ ) div9ity4 ,!y h be5 subjects ( wor%ip p]haps m g5]ally ?an any?+ else1 & ^! e>ly impressions h surviv$ 9 ! c]emonial uses ( light & fire ev5 to ! pres5t "t4 ,! orig9 ( fire z repres5t$ 9 any ( ! my?s ( ! sup]/iti\s be+s ( e>ly ages is z suitable z any o!r1 inasmu* z def9ite k is unavailable4 ,active volcanoes1 spontane\s combu/ion1 friction1 accid5tal focus+ ( ! sun's image1 & o!r means may h introduc$ primitive be+s to fire4 ,a /udy ( savage tribes ( ! pres5t age comb9$ ) a survey ( pa/ hi/ory ( my?ology1 ( mat]ial relics1 & ( ! abs5ce ( lamps or o!r light+ ut5sils leads to ! conclusion t ! e>lie/ s\rce ( light 0 ! wood fire4 ,illu/ration3 ,,primitive ,,fire-,,baskets ,illu/ration3 ,,crude ,,spl9t]-,,hold]s ,illu/ration3 ,,e>ly ,,op5-,,flame ,,oil ,,& ,,grease ,,lamps ,ev5 to-day ! savages ( remote l&s h n advanc$ fur!r ?an ! wood-fire /age1 & !y may be f\nd kneel+ ^u ! gr\nd en]getically b skilfully rubb+ /icks toge!r until ! friction k9dles a fire4 ,9 us+ ^! fire-/icks !y conv]t me*anical en]gy into heat en]gy4 ,?is is a fundam5tal pr9ciple ( physics1 employ$ by !m z necessity dem&s1 b !y are totally ignorant ( x z a sci5tific law4 ,! ?+s :i* ^! savages le>n are ! result ( accid5tal discov]y4 ,until man pond]$ ov] su* simple facts & cord9at$ !m s t he c\ld ext5d 8 k by g5]al reason+1 8 progress c\ld n be rapid4 ,b ! sluggi% m9d ( primitive man is capable ( devis+ improvem5ts1 h[ev] sl[ly1 & ! art ( mak+ fire by means ( rubb+ fire-/icks gradually became m ref9$4 ,me*anical improvem5ts result$ f exp]i5ce1 ) ! consequ5ce t f9ally "o /ick 0 rubb$ to & fro 9 a groove1 or 0 rapidly twirl$ betwe5 ! palms ( ! h&s :ile "o end 0 press$ firmly into a hole 9 a piece ( wood4 ,9 ! c\rse ( a few seconds or a m9ute1 dep5d+ ^u skill & o!r conditions1 a fire 0 obta9$4 ,x is int]e/+ to note h[ civiliz$ man is (t5 compell$ by necessity to adopt ! me?ods ( primitive be+s4 ,! rubb+ ( /icks is an em]g5cy measure ( ! ma/] ( woodcraft at ! pres5t "t1 & ! production ( fire 9 ?is mann] is ! pr\d accompli%m5t or ambition ( e ,boy ,sc\t4 ,:]e only su* crude means ( k9dl+ fire 7 available x became ! cu/om 9 "s cases to ma9ta9 a fire burn+ cont9u\sly 9 a public place4 ,ar\nd ?is pyrtaneum ! v>i\s civil1 political1 & religi\s affairs 7 c>ri$ on by ! light & w>m? ( ! public fire4 ,_m qua9t cu/oms evolv$1 app>5tly1 f ?is anci5t proc$ure4 ,! t9d]-box ( mod]n c5turies d\btless orig9at$ 9 v e>ly times1 = x is inconceivable t ! e>lie/ be+s did n become aw>e ( ! production ( sp>ks :5 c]ta9 /ones 7 /ruck toge!r4 ,9 ! /one age1 :5 human be+s sp5t mu* ( _! "t *isel+ implem5ts & ut5sils f /one by means ( tools ( ! same sub/ance1 x appe>s c]ta9 t ?is means ( produc+ fire 0 ev] app>5t4 ,_m ( _! %>p implem5ts1 su* z knives & arr[-heads1 7 made ( qu>tz & simil> mat]ial & x is likely t ! use ( two pieces ( qu>tz = produc+ a sp>k orig9at$ 9 ^? remote p]iods4 ,alaskan & ,aleutian tribes are kn[n to h employ$ two pieces ( qu>tz cov]$ ) native sulphur4 ,:5 ^! 7 /ruck toge!r ) skill1 excell5t sp>ks 7 obta9$4 ,lat]1 :5 iron & /eel became available1 ! m mod]n t9d]-box 0 develop$4 ,an e>ly application ( ! fl9t-&-/eel pr9ciple 0 made by c]ta9 ,esquimo tribes :o obta9$ fire by /rik+ a piece ( qu>tz aga9/ a piece ( iron pyrites4 ,! latt] is a yell[ sulphide ( iron1 ( cry/all9e =m1 be/ kn[n z fool's gold4 ,d\btless1 ! m primitive be+s us$ dri$ grass1 leaves1 & moss z inflammable mat]ial ^u :i* ! sp>ks 7 %[]$4 ,9 lat] c5turies ! t9d]-box 0 fill$ ) *>r$ grass1 l951 & pap]4 ,!re 0 a long int]val betwe5 ! developm5t ( fire-/icks & t ( ! t9d]-box z measur$ by ! progress ( civilization4 ,dur+ rec5t c5turies ord9>y br[n pap] soak$ 9 saltpet] & dri$ 0 utiliz$ satisfactorily z an inflammable mat]ial4 ,su* devices h be5 employ$ 9 pa/ ages 9 widely sep>at$ regions ( ! e>?4 ,elaborate specim5s ( t9d]-boxes f ,jamaica1 ,japan1 ,*9a1 ,europe1 & v>i\s o!r c\ntries are n[ repos+ 9 ! collections 9 ! possession ( museums & ( individuals4 ,if ! radiant en]gy f ! sun is suffici5tly conc5trat$ ^u inflammable mat]ial1 ! latt] w ignite4 ,su* conc5tration may be a*iev$ by means ( a convex l5s or a concave mirror4 ,?is me?od ( produc+ fire does n ant$ate ! m primitive me?ods su* z /rik+ qu>tz or rubb+ wood5 /icks1 because ! mat]ials requir$ are n readily f\nd or prep>$1 b x is ( v remote orig94 ,ari/ophanes 9 8 com$y ,! ,cl\ds1 :i* is a satire aim$ at ! sci5ce & philosophy ( 8 p]iod 7#dhh-che ,b4 ,c471 m5tions ! burn+ l5s4 ,ne>ly e "o is famili> ) an a*ievem5t attribut$ to ,ar*im$es 9 :i* he de/roy$ ! %ips at ,syracuse by focus+ ! image ( ! sun ^u !m by means ( a concave mirror4 ,! anci5t ,egyptians 7 pr(ici5t 9 ! art ( glass-mak+1 s x is likely t ! burn+-glass 0 employ$ by !m4 ,ev5 a crude l5s ( glass w focus an image ( ! sun suffici5tly well to cause inflammable mat]ial to ignite4 ,! en]gy 9 sunlight v>ies enorm\sly1 ev5 on cle> days1 because ! wat]-vapor 9 ! atmosph]e absorbs "s ( ! radiant en]gy emitt$ by ! sun4 ,?is absorb$ radiation is *iefly kn[n z infra-r$ en]gy1 :i* does n ar\se ! s5sation ( light4 ,:5 ! wat]-vapor cont5t ( ! atmosph]e is high1 ! sun1 ?\gh x may appe> z bright to ! eye1 9 reality is n z hot z x w\ld be if ! wat]-vapor 7 n pres5t4 ,h[ev]1 a fire may be k9dl$ by conc5trat+ only ! visible rays 9 sunlight because ( ! enorm\s int5sity ( sunlight4 ,a convex l5s fa%ion$ f ice by means ( a %>p-edg$ /one & f9ally %ap$ by melt+ ! surfaces z !y are rubb$ 9 ! palms ( ! h&s1 w k9dle a fire 9 highly inflammable mat]ial if ! sun is high & ! atmosph]e is fairly cle>4 ,burn+-glasses are us$ to a consid]able ext5t at ! pres5t "t 9 c]ta9 c\ntries & x is report$ t ,briti% soldi]s 7 suppli$ ) !m dur+ ! ,bo] ,w>4 ,indicative ( ! pr$om9ant use to :i* ! glass l5s 0 appli$ 9 ! pa/ is ! employm5t ( ! t]m burn+-glass in/ead ( l5s 9 ! sci5tific writ+s z late z a c5tury or two ago4 ,z civilization advanc$1 lead+ intellects began to inquire into ! my/]ies ( nature & ! p]iods ( pure philosophy gave way to an era ( me?odical rese>*4 ,al*emy & sup]/ition began to retire be=e ! attacks ( ^? pione]s :o _h ! tem]ity to believe t ! s*eme ( creation involv$ a va/ network ( inv>iable laws4 ,9 ?is mann] ! p[]ful sci5ces ( physics & *emi/ry 7 born a few c5turies ago4 ,among o!r ?+s ! production ( fire & light receiv$ att5tion & ! d>k ages 7 doom$ to end4 ,! crude1 unc]ta91 & inconv5i5t me?ods ( mak+ fire 7 replac$ by /eadily improv+ sci5tific devices4 ,mat*es 7 at fir/ cumb]some1 dang]\s1 & exp5sive1 b ^! gradually evolv$ into ! safety mat*es ( ! pres5t "t4 ,al?\gh !y 7 prim>ily int5d$ = light+ fires & v>i\s k9ds ( lamps1 billions ( !m are n[ us$ ye>ly z conv5i5t light-s\rces4 ,smold]+ hemp or o!r mat]ial treat$ ) nit] & o!r sub/ances 0 an e>ly =m ( mat* us$ especially = dis*>g+ fire>ms4 ,! mod]n wax-tap] is an evolution>y =m ( ?is type ( light-s\rce4 ,phosphorus has long play$ a dom9ant rle 9 ! prep>ation ( mat*es4 ,! fir/ attempt at mak+ !m 9 _! mod]n =m appe>s to h occurr$ ab\t #afhj4 ,small pieces ( phosphorus 7 us$ 9 connection ) small spl9ts ( wood dipp$ 9 sulphur4 ,?is type ( mat* did n come into g5]al use until aft] ! beg9n+ ( ! n9ete5? c5tury1 ow+ to its dang] & exp5se4 ,:ite or yell[ phosphorus is a deadly poison2 !re=e ! progress ( ! phosphorus mat* 0 inhibit$ until ! discov]y ( ! relatively h>mless =m kn[n z r$ phosphorus4 ,! fir/ comm]cial application ( ?is =m 0 made 9 ab\t #ahej4 ,an e>ly +5i\s device consi/$ ( a piece ( phosphorus conta9$ 9 a tube4 ,a pi/on fitt$ snugly into ! tube1 by means ( :i* ! air c\ld be compress$ & ! phosphorus ignit$4 ,sulphur mat*es 7 ignit$ f ! burn+ t9d]1 ! latt] be+ fir$ by fl9t & /eel4 ,9 #ahbh ano!r =m ( mat* consi/$ ( a glass tube conta9+ sulphuric acid & surr\nd$ by a mixture ( *lorate ( pota% & sug>4 ,a pair ( nipp]s 0 suppli$ ) ea* box ( ^! mat*es1 by means ( :i* ! tip ( ! glass tube c\ld be brok5 (f4 ,?is lib]at$ ! acid1 :i* ^u mix+ ) ! o!r +r$i5ts set fire to !m4 ,to ?is contrivance a roll ( pap] 0 atta*$ :i* 0 ignit$ by ! burn+ *emicals4 ,! lucif] or friction mat*es appe>$ 9 ab\t #ahbg1 b successful phosphorus mat*es 7 fir/ made 9 ab\t #ahcc4 ,! s-call$ safety mat* ( ! pres5t "t 0 inv5t$ 9 ! ye> #ahee4 ,to-day1 ! total daily output ( mat*es rea*es millions & p]haps billions4 ,automatic ma*9]y is employ$ 9 prep>+ ! spl9ts ( wood & 9 dipp+ !m into molt5 p>aff9 wax & f9ally into ! ignit+ composition4 ,dur+ rec5t ye>s ! pr9ciple ( ! t9d]-box has be5 reviv$ 9 a device 9 :i* sp>ks are produc$ by rubb+ ! m9]al c]ite 7a hydr\s silicate ( c]ium & alli$ metals7 aga9/ /eel4 ,^! sp>ks ignite a gas-jet or a wick soak$ 9 a highly inflammable liquid su* z gasol5e or alcohol4 ,?is device is a t9d]-box ( ! mod]n sci5tific age4 ,naturally ) ! adv5t ( electricity1 electrical sp>ks came into use = light+ gas-jets & mantles & 9 isolat$ in/ances !y h s]v$ z light-s\rces4 ,d\btless1 e "o is famili> ) ! p>lor /unt ( ignit+ a gas-jet f ! dis*>ge f ! f+]-tips ( /atic electricity accumulat$ by %uffl+ ! feet across ! floor-rug4 ,al?\gh _m ( ^! me?ods & devices h be5 us$ prim>ily = mak+ fire1 !y h s]v$ z em]g5cy or mom5t>y light-s\rces4 ,9 ! outskirts ( civilization "s ( !m are employ$ at ! pres5t "t & v>i\s mod]n light-s\rces require a me?od ( ignition4 ,,iii ,,primitive ,,light-,,s\rces ,_m are famili> ) ! light ( ! firefly or ( its l>v1 ! gl[-worm1 b few p]sons realize t a va/ numb] ( insects & l[] organisms are end[$ ) ! sup]human ability ( produc+ light by physiological processes4 ,app>5tly ! *ief function ( ^! light+-plants )9 ! liv+ bodies is n to provide light 9 ! s5se t ! human be+ uses x pr$om9antly4 ,t is1 ^! wond]ful light-s\rces seem to be utiliz$ m = signal+1 = lur+ prey1 & = protection ?an = /rictly illum9at+-purposes4 ,mu* /udy has be5 giv5 to ! production ( light by animals1 because ! secrets w be extremely valuable to mank9d4 ,z "o floats ov] tide-wat] on a balmy ev5+ aft] d>k & wat*es ! pulsat+ spots ( phosphoresc5t light emitt$ by ! l[ly jellyfi%es1 8 imag9ative mood =mulates ! "q1 ,:y are ^! l[ly organisms end[$ ) su* a wond]ful ability8 ,despite 8 highly develop$ m9d & body & 8 boa/$ sup]iority1 man mu/ g =? & le>n ! secrets ( light-production be=e he may emancipate himself f d>kness4 ,if man c\ld emit light 9 relative proportion to 8 size z comp>$ ) ! firefly1 he w\ld ne$ no o!r tor* 9 ! coal-m9e4 ,h[ indep5d5t he w\ld be 9 extreme d>kness :]e 8 adapt$ eyes ne$ only a feeble light-s\rce6 ,primitive man1 desir+ a light-s\rce & hav+ no means ( mak+ fire1 imprison$ ! gl[+ insects 9 a p]=at$ g\rd or receptacle ( clay1 & ?us inv5t$ ! fir/ lant]n p]haps be=e he knew h[ to make fire4 ,! fireflies ( ! ,we/ ,indies emit a cont9u\s gl[ ( consid]able lum9\s int5sity & ! natives h us$ ^! imprison$ insects z light-s\rces4 ,?us mank9d has exhibit$ 8 sup]iority by adapt+ ! facilities at h& to ! gr[+ requirem5ts :i* 8 indep5d5t nature cont9u\sly n\ri%$4 ,8 insi/5t dem& = indep5d5ce 9 turn has n\ri%$ 8 desire to le>n nature's secrets & ?is desire has increas$ 9 int5sity ?r\gh\t ! ages4 ,! act ( imprison+ a gl[+ insect 0 9 itself no great] /ride along ! highway ( progress ?an ! act ( pick+ a ta/y fruit f its tree4 ,h[ev]1 ! crude lant]n p]haps direct$ 8 primitive m9d to ! possibilities ( artificial light4 ,! flam+ fagot f ! fire 0 ! ance/or ( ! oil-lamp1 ! c&le1 ! lant]n1 & ! electric fla%-light4 ,x is a matt] ( conjecture h[ mu* "t elaps$ be=e 8 feeble intellect became aw>e t res9\s wood af=d$ a bett] light-s\rce ?an woods :i* 7 less inflammable4 ,nev]!less1 p9e knots & simil> res9\s pieces ( wood ev5tually 7 favor$ z tor*es & _! use has p]si/$ until ! pres5t "t4 ,9 "s in/ances 9 anci5t times res9 0 extract$ f wood & burn$ 9 vessels4 ,?is 0 ! =]unn] ( ! grease-& ! oil-lamp4 ,9 ! woods to-day ! craftsman ( ! wilds keeps on ! look\t = live trees saturat$ ) highly inflammable +r$i5ts4 ,view$ f ! pres5t age1 ^! smok+1 flick]+ light-s\rces appe> v crude2 nev]!less !y repres5t a wide gulf betwe5 _! us]s & ^? primitive be+s :o 7 unacqua9t$ ) ! art ( mak+ fire4 ,al?\gh ! wood fire prevail$ z a light-s\rce ?r\gh\t unc\nt$ c5turies1 x 0 subject$ to m or less improvem5t z civilization advanc$4 ,:5 ! wood fire 0 br\ght indoors ! day 0 ext5d$ & e>ly man began to develop 8 crude arts4 ,he ?\ght & plann$ 9 ! com=t & security ( 8 cave or hut4 ,by ! firelight he devis$ implem5ts & ev5 decorat$ 8 /one surr\nd+s ) pictures :i* to-day reveal some?+ ( ! ?\ghts & activities ( mank9d dur+ a civilization :i* exi/$ _m ?\s& ye>s ago4 ,:5 x 0 too w>m to h a ro>+ fire ^u ! he>?1 man devis$ o!r means = obta9+ light )\t undue w>m?4 ,he plac$ gl[+ emb]s ^u l$ges 9 ! walls1 ^u /one slabs1 or ev5 ^u susp5d$ devices ( non-inflammable mat]ial4 ,lat] he split long spl9t]s ( wood f pieces select$ = _! /raightness ( gra94 ,^! burn+ spl9t]s emitt+ a smok+1 feeble light 7 crude b !y 7 ref9em5ts ( consid]able m]it4 ,a te/imonial ( _! satisfactor9ess is _! use ?r\gh\t _m c5turies4 ,until v rec5t times ! burn+ spl9t] has be5 9 use 9 ,scotl& & 9 o!r c\ntries1 & x is probable t at pres5t 9 remote di/ricts ( highly civiliz$ c\ntries ?is crude device s]ves ! meag] ne$s ( ^? ^: requirem5ts h be5 undi/urb$ by ! progress ( civilization4 ,scott1 9 ,! ,leg5d ( ,montrose1 describes a table sc5e dur+ a fea/4 ,beh9d ea* seat a giant ,highl&] /ood1 hold+ a blaz+ tor* ( bog-p9e4 ,?is 0 also ! me?od ( light+ 9 ! ,hom]ic age4 ,crude clay relics repres5t+ a human head1 f ! m\? ( :i* ! wood-spl9t]s project$1 appe> to corroborate ! report t ! flam+ spl9t] 0 sometimes held 9 ! m\? 9 ord] t bo? h&s ( a workman w\ld be free4 ,spl9t]-hold]s ( _m types h surviv$1 b mo/ ( !m are ( ! =m ( a crude p$e/al ) a not* or spr+ clip at its upp] end4 ,! spl9t] 0 held 9 ?is clip & burn$ = a "t dep5d+ ^u its l5g? & ! "* ( ! wood4 ,x 0 ! bus9ess ( c]ta9 individuals to prep>e bundles ( spl9t]s1 :i* 9 ! lat] /ages ( civilization 7 sold at ! m>ket-place or f h\se to h\se4 ,^? :o h obs]v$ ! fronti]sman ev5 among civiliz$ races w be q c]ta9 t ! wood = spl9t]s 0 select$ & split ) skill1 & t ! spl9t]s 7 burn$ "u conditions :i* w\ld yield ! mo/ satisfactory light4 ,x is a *>act]i/ic ( ^? :o live close to nature1 & are ?us limit$ 9 facilities1 to acquire a surpris+ effici5cy 9 _! primitive activities4 ,an obvi\s /ep 9 ! use ( burn+ wood z a light-s\rce 0 to place su* a fire on a %elf or 9 a cavity 9 ! wall4 ,lat] :5 metal 0 available1 grat+s or baskets 7 susp5d$ f ! ceil+ or f brackets & gl[+ emb]s or flam+ *ips 7 plac$ ^u !m4 ,"s ( ^! 7 equipp$ ) crude *imneys to c>ry away ! smoke1 & p]haps to increase ! draft4 ,9 m rec5t c5turies ! fir/ attempt at light+ outdoor public places 0 by means ( metal baskets 9 :i* flam+ wood emitt$ light4 ,x 0 ! duty ( ! wat*man to keep ^! baskets suppli$ ) p9e knots4 ,9 e>ly c5turies /reet-light+ 0 n attempt$1 & no s]i\s ef=ts wor?y ( consid]ation z adequate light+ 7 made e>li] ?an ab\t a c5tury ago4 ,z a consequ5ce ! l9k-boy came into exi/5ce4 ,) flam+ tor* he w\ld escort p$e/rians to _! homes on d>k nights4 ,?is practice 0 9 vogue s rec5tly t ! l9k-boy is rememb]$ by p]sons /ill liv+4 ,9 ,engl& ! pr(ession appe>s to h exi/$ until ab\t #ahdj4 ,some:at ak9 to ! wood-spl9t]1 & a =]unn] ( ! c&le1 0 ! ru%light4 ,9 burn+ wood man notic$ t a res9\s or fatty mat]ial increas$ ! inflammability & add$ greatly to ! am\nt ( light emitt$4 ,x 0 a logical /ep to try to reproduce ?is condition by artificial means4 ,z a consequ5ce ru%es 7 cut & soak$ 9 wat]4 ,!y 7 !n peel$1 leav+ l5g?s ( pi? p>tially support$ by ?reads ( ! sk9 :i* 7 n /ripp$ (f4 ,^! /icks ( pi? 7 plac$ 9 ! sun to blea* & to dry1 & aft] !y 7 ?or\ghly dry !y 7 dipp$ 9 scald+ grease1 :i* 0 sav$ f cook+ op]ations or 0 o!rwise acquir$ = ! purpose4 ,a re$ two or ?ree feet long held 9 ! spl9t]-hold] w\ld burn = ab\t an h\r4 ,?us x is se5 t man 0 beg9n+ to progress 9 ! developm5t ( artificial light4 ,9 develop+ ! ru%light he 0 lay+ ! f\ndation = ! inv5tion ( ! c&le4 ,pl9y has m5tion$ ! burn+ ( re$s soak$ 9 oil z a feature ( fun]al rites4 ,_m crude =]unn]s ( ! c&le 7 develop$ 9 v>i\s p>ts ( ! _w by diff]5t races4 ,= example1 ! ,malays made a tor* by wrapp+ res9\s gum 9 palm leaves1 ?us devis+ a crude c&le ) ! wick on ! outside4 ,_m primitive uses ( vegetable & animal fats 7 =]unn]s ( ! oil-lamp4 ,9 ! ,ea/ ,indies ! c&leb]ry1 :i* conta9s oily se$s1 has be5 burn$ = light by ! natives4 ,9 _m cases burn+ fi% & birds h s]v$ z lamps4 ,9 ! ,orkney ,isl&s ! c>cass ( a /ormy petrel ) a wick 9 its m\? has be5 utiliz$ z a light-s\rce1 & 9 ,alaska a fi% 9 a split /ick has provid$ a crude tor* = ! natives4 ,^! primitive me?ods ( obta9+ artificial light h be5 employ$ = c5turies & _m are 9 use at ! pres5t "t among unciviliz$ tribes & ev5 by civiliz$ be+s 9 ! remote outskirts ( civilization4 ,surely progress is limit$ :]e a burn+ fi% s]ves z a tor*1 or :]e1 at be/1 ! light-s\rces are feeble1 smok+1 flick]+1 & ill-smell+6 ,progress insi/$ ^u a light-s\rce :i* 0 free f ! defects ( ! crude devices already describ$ & ! next developm5ts 7 improvem5ts to ! ext5t at lea/ t combu/ion 0 m ?or\gh4 ,! e>ly oil-lamps & c&les did n emit mu* smoke1 b !y 7 /ill feeble light-s\rces & n always )\t noticeable odors4 ,nev]!less1 !y m>k$ a trem5d\s advance 9 ! production ( artificial light4 ,al?\gh !y 7 n sci5tific developm5ts 9 ! mod]n s5se1 ! e>ly oil-lamp & ! c&le repres5t$ ! great possibilities ( utiliz+ k r ?an dep5d+ ^u ! raw products ( nature 9 unmodifi$ =ms4 ,! adv5t ( ^! two light-s\rces 9 reality m>k$ ! beg9n+ ( ! civilization :i* 0 de/9$ to progress & survive4 ,al?\gh su* primitive light-s\rces z ! flam+ spl9t] & ! gl[+ emb] h surviv$ until ! pres5t age1 lamps consi/+ ( a wick dipp$ into a receptacle conta9+ animal & vegetable oils h be5 9 use among ! m advanc$ peoples s9ce prehi/oric times4 ,oil-lamps are to be se5 9 ! e>lie/ ,roman illu/rations4 ,dur+ ! height ( anci5t civilization along ! ea/]n %ores ( ! ,m$it]ranean ,sea1 elaborate light+ 0 effect$ by means ( ! %all[ grease-or oil-lamp4 ,x is difficult to e/imate ! age 9 :i* ?is =m ( light-s\rce orig9at$1 b "s lamps 9 exi/5ce 9 collections at ! pres5t "t appe> to h be5 made z e>ly z f\r or five ?\s& ye>s be=e ! ,*ri/ian era4 ,x is notewor?y t su* lamps did n diff] mat]ially 9 ess5tial details f ^? 9 use z late z a few c5turies ago4 ,at fir/ ! grease us$ 0 ! crude fat f animals4 ,vegetable oils also 7 burn$ 9 ! e>ly lamps4 ,! ,japanese1 = example1 extract$ oil f nuts4 ,:5 ! dem&s ( civilization increas$1 ext5sive ef=ts 7 made to obta9 ! requir$ fats & oils4 ,amphibi\s animals ( ! ,nor? & ! huge mammals ( ! sea 7 slaught]$ = _! fat1 & vegetable s\rces 7 cultivat$4 ,lat]1 sp]m & colza 7 ! mo/ common oils us$ by ! advanc$ races4 ,! =m] is an animal oil obta9$ f ! head cavities ( ! sp]m-:ale2 ! latt] is a vegetable oil obta9$ f rape-se$4 ,m9]al oil 0 introduc$ z an illum9ant 9 #ahec1 & ! mod]n lamp came into use4 ,! grease-& oil-lamps 9 g5]al 7 ( su* a =m t !y c\ld be c>ri$ ) ease & !y _h flat bottoms s t !y w\ld re/ securely4 ,! simple/ =ms _h a s+le wick1 b 9 o!rs _m wicks dipp$ into ! same receptacle4 ,! e>ly ones 7 ( /one1 b lat]1 lamps 7 model$ f clay or t]ra cotta & f9ally f metals4 ,!y 7 usually cov]$ & ! wick project$ ?r\gh a hole 9 ! top ne> ! edge4 ,l>ge /one vases fill$ ) a hundr$ p\nds ( liquid fat are kn[n to h be5 us$ 9 e>ly times4 ,z a "p ( ! sett+ 9 ! celebration ( fe/ivals ! anci5t nations ( ,asia & ,africa plac$ along ! /reets bronze vases fill$ ) liquid fat4 ,! ,esquimaux to-day use ?is =m ( lamp1 9 :i* :ale-oil & seal blubb] is ! fuel4 ,incid5tally1 ^! lamps also supply ! only artificial heat = _! huts & igloos4 ,! heat f ^! feeble light-s\rces & f _! bodies keeps ^! natives ( ! arctics w>m )9 ! icy walls ( _! abodes4 ,v beautiful oil-lamps ( brass1 bronze1 & pewt] evolv$ 9 su* c\ntries z ,egypt4 ,_m ( ^! 7 design$ = & us$ 9 religi\s c]emonies4 ,! oil-lamps ( ,*9a1 ,scotl&1 & o!r c\ntries 9 lat] c5turies 7 improv$ by ! addition ( a pan b5ea? ! oil-receptacle1 to cat* dripp+s f ! wick or oil :i* might run ov] dur+ ! fill+4 ,! ,*9ese lamps 7 sometimes made ( bamboo1 b ! ,scotti% lamps 7 made ( metal4 ,a flat metal lamp1 call$ a crusie1 0 "o ( ! *ief products ( blacksmi?s & 0 common 9 ,scotl& until ! middle ( ! n9ete5? c5tury4 ,?is type ( lamp 0 us$ by _m nations & has be5 f\nd 9 ! catacombs ( ,rome4 ,! crusie 0 usually susp5d$ by an iron hook & ! fl[ ( oil to ! wick c\ld be regulat$ by tilt+4 ,! wick 9 ! ,scotti% lamps consi/$ ( ! pi? ( ru%es1 clo?1 or twi/$ ?reads4 ,^! e>ly oil-lamps 7 almo/ always %all[ vessels into :i* a %ort wick 0 dipp$1 & x 0 n until ! latt] "p ( ! eighte5? c5tury t o!r =ms came into g5]al use4 ,! *ange 9 =m 0 due *iefly to ! introduction ( sci5tific k :5 m9]al oil 0 introduc$4 ,z e>ly z #agha ! burn+ ( nap?a obta9$ by di/ill+ coal at l[ temp]atures 0 fir/ discuss$1 b no g5]al applications 7 made until a lat] p]iod4 ,?is 0 ! beg9n+ ( _m m>k$ improvem5ts 9 oil-lamps1 & 0 9 reality ! bir? ( ! mod]n sci5ce ( light-production4 ,illu/ration3 ,a ,,typical ,,metal ,,multiple-,,wick ,,op5-,,flame ,,oil-,,lamp ,illu/ration3 ,a ,,gr\p ,,( ,,oil-,,lamps ,,( ,,two ,,c5turies ,,ago ,z ! activities ( man became m complex he met f 8 gr[+ /ore ( k ! increas+ requirem5ts ( light+4 ,9 consequ5ce1 _m +5i\s devices = light+ 7 evolv$4 ,= example1 9 ,engl& 9 ! sev5te5? c5tury man 0 already burr[+ into ! e>? = coal & ( c\rse enc\nt]$ coal-gases4 ,^! inflammable gases 7 fir/ kn[n = ! direful effects :i* !y s (t5 produc$ r ?an = _! useful qualities4 ,al?\gh !y 7 kn[n to m9]s long be=e !y receiv$ sci5tific att5tion1 ! e>lie/ acc\nt ( !m 9 ! ,transactions ( ! ,royal ,society 0 pres5t$ 9 ! ye> #affg4 ,a description ( e>ly gas-light+ has be5 res]v$ = a lat] *apt]1 b ! =ego+ is not$ at ?is po9t to introduce a novel e>ly me?od ( light+ 9 coal-m9es :]e inflammable gases 7 enc\nt]$4 ,9 discuss+ ?is coal-gas ano!r e>ly writ] /at$ t x w n take fire except by flame & t sp>ks d n affect x4 ,"o ( ! e>ly solutions ( ! problem ( artificial light+ "u su* conditions is summ>iz$ z foll[s3 ,be=e ! inv5tion ( ,sir ,humphrey ,davy's ,safety ,lamp1 ?is prop]ty ( ! gas gave rise to a v>iety ( contrivances = af=d+ ! m9]s suffici5t light to pursue _! op]ations2 & "o ( ! mo/ useful ( ^! inv5tions 0 a mill = produc+ light by sp>ks elicit$ by ! collision ( fl9t & /eel4 ,su* a /ream ( sp>ks may appe> a v crude & unsatisfactory solution z judg$ by pres5t /&>ds1 b x 0 at lea/ an +5i\s application ( ! facilities available at t "t4 ,v>i\s o!r devices 7 resort$ to 9 ! coal-m9es be=e ! introduction ( a safety lamp4 ,9 discuss+ ! c&le x is necess>y aga9 to g back to an e>ly p]iod1 = x sl[ly evolv$ 9 ! c\rse ( _m c5turies4 ,x is ! natural desc5dant ( ! ru%light1 ! grease-lamp1 & v>i\s primitive devices4 ,until ! adv5t ( ! m sci5tific age ( artificial light+1 ! c&le /ood prem95t among e>ly light-s\rces4 ,x did n emit appreciable smoke or odor & x 0 conv5i5tly portable & less fragile ?an ! oil-lamp4 ,c&les h be5 us$ ?r\gh\t ! ,*ri/ian era & "s au?orities are incl9$ to attribute _! orig9 to ! ,pho5icians4 ,x is kn[n t ! ,romans us$ !m1 especially ! wax-c&les1 9 religi\s c]emonies4 ,! ,pho5icians introduc$ !m into ,byzantium1 b !y disappe>$ "u ! ,turki% rule & did n come into use aga9 until ! twelf? c5tury4 ,! wax-c&le 0 v mu* m exp5sive ?an ! tall[-c&le until ! fifte5? c5tury1 :5 its relative co/ 0 some:at r$uc$1 br++ x )9 ! means ( a great] proportion ( ! p4 ,nev]!less x has long be5 us$1 *iefly by ! weal?y2 ! dep>t+ gue/ ( ! e>ly ,victorian inn w\ld be likely to f9d an item on 8 bill su* z ?is3 ,= a g5tleman :o call$ himself a g5tleman1 wax-lights1 #e_/4 ,poor m5 us$ tall[ dips or w5t to b$ 9 ! d>k4 ,x is int]e/+ to note ! importance ( ! c&le 9 ! h\sehold budget ( e>ly times 9 v>i\s say+s4 ,= example1 ,! game is n wor? ! c&le1 implies t ! co/ ( c&le-light 0 n ignor$4 ,9 ^! days little att5tion is giv5 to ! co/ ( artificial light "u simil> conditions4 ,if a p]son burns a c&le at bo? ends he is wa/eful & oblivi\s to ! consequ5ces ( extravagance :e!r 9 mat]ial goods or 9 human en]gy4 ,) ! rise ( ! ,*ri/ian *ur*1 c&les came to be us$ 9 religi\s c]emonies & _m ( ! symbolisms1 mean+s1 & cu/oms survive to ! pres5t "t4 ,"s ( ! f9e/ art ( pa/ c5turies is f\nd 9 ! old c&le/icks4 ,_m ( ^! antiques1 :i* (ttimes 7 gifts to ! *ur*1 h be5 pres]v$ to po/]ity by ! *ur*4 ,! influ5ce ( ^! light+ accessories is (t5 not$ 9 mod]n light+-fixtures1 b un=tunately e>ly art (t5 suff]s f adaptation to ! requirem5ts ( mod]n light-s\rces1 or ! eyesight suff]s f a s5seless devotion to art :i* results 9 ! use ( mod]n light-s\rces1 un%ad$ & gl>+1 9 places :]e x 0 unnecess>y to %ade ! feeble c&le4 ,! olde/ mat]ials employ$ = mak+ c&les are beeswax & tall[4 ,! beeswax 0 blea*$ be=e use4 ,! tall[ 0 melt$ & /ra9$ & !n cotton or flax fib]s 7 dipp$ into x repeat$ly1 until ! desir$ ?ickness 0 obta9$4 ,9 e>ly c5turies ! pi? ( ru%es 0 us$ = wicks4 ,tall[ is n[ us$ only z a s\rce ( /e>9e4 ,sp]maceti1 a fatty sub/ance obta9$ f ! sp]m-:ale1 0 introduc$ into c&le-mak+ 9 ab\t #agej & great numb]s ( m5 se>*$ ! sea to fill ! gr[+ dem&s4 ,p>aff9 wax1 a mixture ( solid hydroc>bons obta9$ f petroleum1 came into use 9 #ahed & /e>9e is n[ us$ ) x4 ,! latt] increases ! rigidity & decreases ! brittl5ess ( ! c&le4 ,"s ( ! mod]n c&les are made ( a mixture ( /e>9e & ! h>d fat extract$ f cocoanut-oil4 ,mod]n c&les v>y 9 composition1 b all are ! product ( mu* exp]i5ce & ( ! application ( sci5tific k4 ,! wicks are n[ made *iefly ( cotton y>n1 braid$ or plait$ by ma*9]y & *emically treat$ to aid 9 complete combu/ion :5 ! c&le is burn$4 ,_! /ructure is ! result ( long exp]i5ce & !y are n[ made s t !y b5d & dip into ! molt5 fuel & are :olly consum$4 ,?is elim9ates ! necessity ( trimm+4 ,c&les h be5 made 9 v>i\s ways1 includ+ dipp+1 p\r+1 draw+1 & mold+4 ,wax-c&les are made by p\r+1 because wax _c be mold$ satisfactorily4 ,draw+ is some:at simil> to dipp+1 except t ! process is m or less cont9u\s & is c>ri$ out by ma*9]y4 ,mold+1 z ! t]m implies1 involves ! use ( molds1 ( ! size & %ape desir$4 ,! c&le/ick evolv$ f ! mo/ primitive wood5 objects to elaborately design$ & decorat$ works ( art4 ,! primitive c&le/ick 0 crude & 0 no m ?an a hold] ( "s k9d = keep+ ! c&le upright4 ,lat] a =m ( cup 0 atta*$ to ! /em ( ! hold]1 to cat* ! dripp+ wax or fat4 ,! latt] improvem5t has p]si/$ ?r\gh\t ! c5turies4 ,! mod]n c&le is by no means an unsatisfactory light-s\rce4 ,^? :o h _h exp]i5ce ) x 9 ! outskirts ( civilization w te/ify t x possesses sev]al desirable *>act]i/ics4 ,supplies ( c&les are transport$ )\t difficulty2 ! light$ c&le is easily c>ri$ ab\t2 & ! light 9 a quiesc5t atmosph]e is q satisfactory1 if common s5se is us$ 9 %ad+ & plac+ ! c&le4 ,al?\gh 9 a s5se a primitive light-s\rce1 x is a bless+ 9 _m cases &1 incid5tally1 x is ext5sively us$ to-day 9 indu/ries1 9 religi\s c]emonies1 z a decorative elem5t at banquets1 & 9 ! outpo/s ( civilization4 ,?is acc\nt ( ! evolution ( light-s\rces has cross$ ! ?re%old ( :at may be t]m$ mod]n sci5tific light-production 9 ! case ( ! c&le & ! oil-lamp4 ,!re is a p]iod ( a c5tury or m dur+ :i* sci5tific progress 0 sl[1 b ^? ye>s pav$ ! way = ! extraord9>y developm5ts ( ! la/ few decades4 ,,iv ,,! ,,c]emonial ,,use ,,( ,,light ,inasmu* z ! symbolisms & c]emonial uses ( light orig9at$ 9 ! *ildhood ( ! human race & 7 n\ri%$ ?r\gh\t ! age ( my?ology1 ! e>ly light-s\rces are associat$ m ) ?is phase ( artificial light ?an mod]n ones4 ,= ?is reason x appe>s appropriate to pres5t ?is discussion be=e ent]+ into ! lat] /ages ( ! developm5t & utilization ( artificial light4 ,fur!rmore1 _m ( ! traditions ( light+ at ! pres5t "t are survivors ( ! e>ly ages4 ,light+-fixtures %[ ! influ5ce ( ?is byway ( light+1 & 9 ^? cases :]e ! c]emonial use ( light has surviv$ to ! pres5t "t1 mod]n light-s\rces _c be employ$ wisely 9 replac+ m primitive ones )\t consid]ation ( ! orig9 & exi/5ce ( ! cu/oms4 ,9 fact1 c&les are likely to be us$ = hundr$s ( ye>s to come1 ow+ to ! s5tim5t connect$ ) !m & to ! e/abli%$ cu/oms f\nd$ ^u c5turies ( traditional use4 ,d\btless1 ! sun z a s\rce ( heat & light & ( ! bless+s :i* ^! br+ to e>?1 is responsible l>gely = ! div9e significance be/[$ ^u light4 ,d>kness v des]v+ly acquir$ _m uncomplim5t>y attributes1 = dang] lurk$ beh9d its veil & x 0 ! suitable abode ( evil spirits4 ,x h>bor$ all t 0 ! anti!sis ( goodness1 happ9ess1 & security4 ,light naturally became sacr$1 life-giv+1 & symbolic ( div9e pres5ce4 ,fire 0 to primitive be+s ! mo/ impressive ph5om5on ov] :i* !y _h any control1 & x 0 suffici5tly my/]i\s 9 its op]ation to w>rant a connection ) ! sup]natural4 ,?us x 0 v natural t ^! e>li] be+s wor%ip$ x z repres5t+ div9e pres5ce4 ,! sun1 z ,ra1 0 "o ( ! *ief gods ( ! anci5t ,egyptians2 & ! ,assyrians1 ! ,babylonians1 ! anci5t ,greeks1 & _m o!r e>ly peoples gave a high place to ?is deity4 ,among simpl] races ! sun 0 (t5 ! sole object ( wor%ip1 & ^? peoples :o wor%ip ,light z ! god ( all1 9 a s5se are n f> afield4 ,fire-wor%ip]s g5]ally consid]$ fire z ! pure/ repres5tation ( heav5ly fire1 ! orig9 ( ev]y?+ t lives4 ,light 0 consid]$ su* a bless+ t lamps 7 buri$ ) ! dead 9 ord] t spirits %\ld be able to h x 9 ! next _w4 ,?is cu/om has prevail$ widely b ! fact t ! lamps 7 unlight$ indicates t only ! mat]ial aspect 0 consid]$4 ,x is int]e/+ to note t ! lamps & o!r light-s\rces 9 pagan temples & religi\s processions 7 n symbolical b 7 (f]+s to ! gods4 ,9 lat] c5turies a deep] symbolical mean+ became atta*$ to light & burn+ lamps 7 plac$ ^u ! tombs ( important p]sonages4 ,! bury+ ( lamps ) ! dead appe>s to h orig9at$ 9 ,asia4 ,! ,pho5icians & ,romans app>5tly cont9u$ ! cu/om1 b no traces ( x h be5 f\nd 9 ,greece & ,egypt4 ,fire & light h be5 closely associat$ 9 v>i\s religi\s cre$s & _! c]emonies4 ,! ,h9du fe/ival 9 honor ( ! goddess ( prosp]ity is att5d$ by ! burn+ ( _m lamps 9 ! temples & homes4 ,! ,jewi% synagogues h _! et]nal lamps & 9 _! rituals fire & light h play$ prom95t rles4 ,! dev\t ,brahman ma9ta9s a fire on ! he>? & wor%ips x z omnisci5t & div9e4 ,he expects a br& f ?is to be us$ to light 8 fun]al pyre1 ^: fire & light w make 8 _s fit to ent] 8 heav5ly abode4 ,he keeps a fire burn+ on ! alt>1 wor%ips ,agni1 ! god ( fire1 & makes fire sacrifices on v>i\s occasions su* z betro?als & m>riages4 ,to ! ,mohamm$ans light$ lamps symbolize holy places1 & ! ,kaaba at ,mecca1 :i* conta9s a black /one suppos$ to h be5 br\ght f heav51 is illum9at$ by ?\s&s ( lamps4 ,_m ( ! uses to :i* light 0 put 9 anci5t times indicate its r>ity & sacr$ nature4 ,d\btless1 ! increas+ use ( artificial light at fe/ivals & celebrations ( ! pres5t "t is p>tly ! result ( l+]+ cu/oms ( bygone c5turies & p>tly due to a recognition ( an innate appeal or attribute ( light4 ,c]ta9ly no?+ is m g5]ally appropriate 9 repres5t+ joy & prosp]ity4 ,?r\gh\t all c\ntries anci5t races _h wov5 natural light & fire into _! rites & cu/oms1 s x became a natural /ep to utilize artificial light & fire 9 ! same mann]4 ,x w\ld be t$i\s & monoton\s to survey ! va/ field ( anci5t wor%ip ( light1 = ! und]ly+ ideas are g5]ally simil>4 ,! my?ology ( ! ,greeks is illu/rative ( ! importance atta*$ to fire & light by ! cultivat$ peoples ( anci5t times4 ,! my? ( ,prome!us emphasizes ! fact t 9 ^? remote p]iods fire & light 7 reg>d$ z ( prime importance4 ,accord+ to ?is my?1 fire & light 7 conta9$ 9 heav5 & great cunn+ & d>+ 7 necess>y 9 ord] to obta9 x4 ,prome!us /ole ?is heav5ly fire1 = :i* act he 0 *a9$ to ! m\nta9 & made to suff]4 ,! ,greeks m>k ?is ev5t z ! beg9n+ ( human civilization4 ,all arts are trac$ to ,prome!us1 & all e>?ly woe likewise4 ,z pa/ hi/ory is survey$ x appe>s natural to ?9k ( sci5tific m5 :o h become m>tyrs to ! que/ ( hidd5 secrets4 ,!y h made great sacrifices = ! future b5efit ( civilization & n a few ( !m h endur$ p]secution ev5 9 rec5t times4 ,! ,greeks recogniz$ t a new era began ) ! acquisition ( artificial light4 ,its div9e nature 0 recogniz$ & x became a ph5om5on = wor%ip & a means = repres5t+ div9e pres5ce4 ,! orig9 ( fire & light made !m holy4 ,! fire on ! alt> took its place 9 religi\s rites & !re evolv$ _m c]emonial uses ( lamps1 c&les1 & fire4 ,! ,greeks & ,romans burn$ sacr$ lamps 9 ! temples & utiliz$ light & fire 9 _m c]emonies4 ,! tor*-race1 9 :i* "y m5 ran ) light$ tor*es1 ! w9n] be+ ! "o :o rea*$ ! goal fir/ ) 8 tor* /ill alight1 orig9at$ 9 a ,grecian c]emony ( light+ ! sacr$ fire4 ,!re are _m ref]5ces 9 anci5t ,roman & ,grecian lit]ature to sacr$ lamps burn+ day & night 9 sanctu>ies & be=e /atues ( gods & h]oes4 ,on bir?days & fe/ivals ! h\ses ( ! ,romans 7 specially ornam5t$ ) burn+ lamps4 ,! ,ve/al ,virg9s 9 ,rome ma9ta9$ ! sacr$ fire :i* _h be5 br\ght by fugitives f ,troy4 ,9 anci5t ,rome :5 ! fire 9 ! ,temple ( ,ve/a became ext+ui%$1 x 0 rek9dl$ by ! rubb+ ( a piece ( wood ^u ano!r until fire 0 obta9$4 ,?is 0 c>ri$ into ! temple by ! ,ve/al ,virg9 & ! sacr$ fire 0 rek9dl$4 ,! fire produc$ 9 ?is mann]1 = "s reason1 0 consid]$ holy4 ,! e>ly peoples display$ _m lamps on fea/-days & an example ( extravagance 9 ?is respect is an occasion :5 ,k+ ,con/ant9e comm&$ t ! entire city ( ,con/ant9ople be illum9at$ by wax-c&les on ,*ri/mas ,eve4 ,c&elabra1 ( ! =m ( ! bran*+ tree1 7 commonly 9 use 9 ! ,roman temples4 ,! c]emonial use ( light 9 ! ,*ri/ian *ur* evolv$ bo? f adaptations ( pagan cu/oms & ( ! natural symbolisms ( fire & light4 ,h[ev]1 ^! acquir$ a deep] mean+ 9 ,*ri/ianity ?an 9 e>ly times because !y 7 prim>ily visible repres5tations or manife/ations ( ! div9e pres5ce4 ,! ,bible conta9s _m ref]5ces to ! importance & symbolisms ( light & fire4 ,accord+ to ! ,fir/ ,book ( ,moses1 ! a*ievem5t ( ! ,creator imm$iately foll[+ ! creation ( ! heav5s & ! e>? 0 ! creation ( light4 ,! ^w light is ! =ty-six? ^w 9 ,g5esis4 ,*ri/ is ! true light & ,*ri/ians are *ildr5 ( light 9 w> aga9/ ! evil p[]s ( d>kness4 ,:5 ,/4 ,paul 0 conv]t$ !re %9$ ab\t him a great light f heav54 ,! impressiv5ess & symbolism ( fire & light are te/ifi$ to 9 _m biblical expressions4 ,*ri/ /&s 9 ! mid/ ( sev5 c&le-/icks ) 8 eyes z a flame ( fire4 ,:5 ! ,holy ,gho/ appe>$ be=e ! apo/les !re appe>$ unto !m clov5 tongues ( fire4 ,:5 ,/4 ,paul 0 prea*+ ! gospel ( ,*ri/ at ,alex&ria !re 7 _m lights sugge/+ a fe/ive illum9ation4 ,accord+ to ! ,bible1 ! p]petual fire :i* came orig9ally f heav5 0 to be kept burn+ on ! alt>4 ,x 0 holy & ^? ^: duty x 0 to keep x burn+ 7 guilty ( a grave (f5se if !y all[$ x to be ext+ui%$4 ,if human h&s 7 p]mitt$ to k9dle x1 puni%m5t 0 met$ out4 ,! two sons ( ,a>on :o (f]$ /range fire be=e ! ,"l 7 dev\r$ by fire f ! ,"l4 ,! sev5-bran*$ c&le/ick 0 light$ et]nally & ^! burn+ light-s\rces 7 necess>y accompanim5ts ( wor%ip4 ,! c\ntless c]emonial uses ( fire & light :i* _h evolv$ 9 ! pa/ c5turies 7 b\nd to influ5ce ! rites & cu/oms ( ! ,*ri/ian *ur*4 ,! fe/ive illum9ation ( pagan temples 9 honor ( gods 0 c>ri$ ov] into ! ,*ri/ian era4 ,! ,*ri/mas tree ( to-day is incomplete )\t its _m lights4 ,its illum9ation is a homage ( light to ! s\rce ( light4 ,! celebration ( ,ea/] 9 ! ,*ur* ( ! ,holy ,sepul*re 9 ,j]usalem is a typical example ( fire-wor%ip reta9$ f anci5t times4 ,at ! climax ( ! s]vices comes ! desc5t ( ! ,holy ,fire4 ,! c5tral c&elabra sudd5ly becomes ablaze & ! wor%ip]s1 ea* ( :om c>ries a wax tap]1 light _! c&les !refrom & ru% ?r\gh ! /reets4 ,! fire is consid]$ to be ( div9e orig9 & is a symbol ( resurrection4 ,! cu/om is simil> 9 mean+ to ! light :i* 9 old] times 0 ma9ta9$ be=e gods4 ,dur+ ! fir/ two or ?ree c5turies ( ! ,*ri/ian era ! c]emonial use ( light does n appe> to h be5 v ext5sive4 ,writ+s ( ! p]iod conta9 /atem5ts :i* appe> to ridicule ?is use to "s ext5t4 ,= example1 "o writ] ( ! second c5tury /ates t ,on days ( rejoic+ 444 we d n encroa* ^u daylight ) lamps4 ,ano!r1 9 ! f\r? c5tury1 ref]s ) s>casm to ! hea!n practice 9 ?is mann]3 ,!y k9dle lights z ?\gh to "o :o is 9 d>kness4 ,c he be ?\ght sane :o (f]s ! light ( lamps & c&les to ! ,au?or & ,giv] ( all light8 ,t c&les 7 light$ 9 cemet]ies is evid5c$ by an edict :i* =bade _! use dur+ ! day4 ,lamps ( ! e>ly c5turies ( ! ,*ri/ian era h be5 f\nd 9 ! catacombs ( ,rome :i* are ?\ght to h be5 c]emonial lamps1 = !y 7 n buri$ ) ! dead4 ,!y 7 f\nd only 9 ni*es 9 ! walls4 ,dur+ ^! same c5turies elaborate c&elabra conta9+ hundr$s ( c&les 7 kept burn+ be=e ! tombs ( sa9ts4 ,not)/&+ ! d\bt t exi/s z to ! ext5t ( c]emonial light+ 9 ! e>ly c5turies ( ! ,*ri/ian era1 x is c]ta9 t by ! beg9n+ ( ! fif? c5tury ! c]emonial use ( light 9 ! ,*ri/ian *ur* _h become v ext5sive & firmly e/abli%$4 ,t ?is is true & t !re 7 /ill "s objections is indicat$ by _m controv]sies4 ,"s ?\ght t lamps be=e tombs 7 ensigns ( idolatry & o!rs felt t no h>m 0 done if religi\s p ?us tri$ to honor m>tyrs & sa9ts4 ,"s e>ly writ+s convey ! idea t ! rituali/ic use ( lights 9 ! *ur* arose f ! ret5tion ( lights necess>y at nocturnal s]vices aft] ! h\rs ( wor%ip _h be5 *ang$ to daytime4 ,pass+ beyond ! e>ly controv]sial p]iod1 ! c]emonial use ( light is ev]y:]e 9 evid5ce at ord9>y *ur* s]vices4 ,on special occasions su* z fun]als1 baptisms1 & m>riages1 elaborate alt>-light+ 0 cu/om>y4 ,! gorge\s c&elabra & ! et]nal lamp are not$ 9 _m writ+s4 ,e>ly 9 ! fif? c5tury ! pope ord]$ t c&les be bless$ & provid$ rituals = ?is c]emony4 ,%ortly aft] ?is ! ,fea/ ( ,purification ( ! ,virg9 0 inaugurat$ & x became kn[n z ,c&lemas because on ?is day ! c&les = ! entire ye> 7 bless$4 ,h[ev]1 x appe>s t ! bless+ ( c&les 0 n c>ri$ out 9 all *ur*es4 ,alt> lights 7 n g5]ally us$ until ! ?irte5? c5tury4 ,!y 7 orig9ally ! sev5 c&les c>ri$ by *ur* (ficials & plac$ ne> ! alt>4 ,! cu/om ( plac+ light$ lamps be=e ! tombs ( m>tyrs 0 gradually ext5d$ to ! plac+ ( su* lamps be=e v>i\s objects ( a sacr$ or div9e relation4 ,f9ally c]ta9 light-s\rces !mselves became objects ( wor%ip & 7 surr\nd$ by o!r lamps1 & ! symbolisms ( light grew apace4 ,a bi%op 9 ! six? c5tury h]ald$ ! triple (f]+ to ,god repres5t$ by ! burn+ wax-c&le4 ,he po9t$ out t ! ru%-wick develop$ f pure wat]2 t ! wax 0 ! product ( virg9 bees2 & t ! flame 0 s5t f heav54 ,ea* ( ^!1 he 0 c]ta91 0 an (f]+ acceptable to ,god4 ,wax-c&les became associat$ *iefly ) religi\s c]emonies4 ,! wax lat] became symbolic ( ! ,bless$ ,virg9 & ( ! body ( ,*ri/4 ,! wick 0 symbolical ( ,*ri/'s s\l1 ! flame repres5t$ 8 div9e "*1 & ! burn+ c&le ?us became symbolical ( 8 dea?4 ,! lamp1 lant]n1 & tap] are frequ5tly symbols ( piety1 heav5ly wisdom1 or spiritual light4 ,fire & flames are emblems ( zeal & f]vor or ( ! suff]+s ( m>tyrdom & ! flam+ he>t symbolizes f]v5t piety & spiritual or div9e love4 ,by ! "t ! ,middle ,ages 7 rea*$ ! c]emonial uses ( light became v complex1 b = ! ,roman ,ca?olic ,*ur* !y may be divid$ into ?ree g5]al gr\ps3 7#a7 ,!y 7 symbolical ( ,god's pres5ce or ( ! effect ( 8 pres5ce2 ( ,*ri/ or ( ! *ildr5 ( light2 or ( joy & cont5t at fe/ivals4 7#b7 ,!y may be (f]$ 9 fulfillm5t ( a religi\s v[2 t is1 z an act ( wor%ip4 7#c7 ,!y may possess c]ta9 div9e p[] because ( _! be+ bless$ by ! *ur*1 & !re=e may be helpful to s\l & body4 ,! ?ree conceptions are indicat$ 9 ! pray]s (f]$ at ! bless+ ( ! c&les on ,c&lemas z foll[s3 7#a7 ,o holy ,"l 444 :o 444 by ?y comm& did/ cause ?is liquid to come by ! labor ( bees to ! p]fection ( wax1 444 we besee* !e 444 to bless & sanctify ^! c&les = ! use ( m51 & ! heal? ( bodies & s\ls4444 7#b7 444^! c&les1 :i* we ?y s]vants desire to c>ry light$ to magnify ?y "n2 t by (f]+ !m to !e1 be+ wor?ily inflam$ ) ! holy fire ( ?y mo/ sweet *>ity1 we may des]ve4444 7#c7 ,o ,"l ,jesus ,*ri/1 ! true light1 444 m]cifully grant1 t z ^! lights enk9dl$ ) visible fire dispel nocturnal d>kness1 s our he>ts illum9at$ by visible fire1 etc4 ,9 g5]al1 ! c]emonial uses ( lights 9 ?is *ur* 7 orig9at$ z a =ceful repres5tation ( ,*ri/ & ( salvation4 ,on ! eve ( ,ea/] a new fire1 emblematic ( ! aris5 ,*ri/1 is k9dl$1 & all c&les ?r\gh\t ! ye> are light$ f ?is4 ,dur+ ! s]vice ( ,holy ,week ?irte5 light$ c&les are plac$ be=e ! alt> & z ! p5it5tial songs are sung !y are ext+ui%$ "o by "o4 ,:5 b "o rema9s burn+ x is c>ri$ beh9d ! alt>1 ?us symboliz+ ! la/ days ( ,*ri/ on e>?4 ,x is said t ?is c]emony has be5 trac$ to ! eigh? c5tury4 ,on ,ea/] ,eve1 aft] ! new fire is light$ & bless$1 c]ta9 c]emonies ( light symbolize ! resurrection ( ,*ri/4 ,f ?is new fire ?ree c&les are light$ & f ^! ! ,pas*al ,c&le4 ,! orig9 ( ! latt] is unc]ta91 b x symbolizes a victori\s ,*ri/4 ,f x all ! c]emonial lights ( ! *ur* are light$ & !y !reby are emblematic ( ! pres5ce ( ! light ( ,*ri/4 ,_m int]e/+ c]emonial uses may be trac$ out1 b space p]mits a glimpse ( only a few4 ,at baptismal s]vices ! pas*al c&le is dipp$ into ! wat] s t ! latt] w be effective z a reg5]ative elem5t4 ,! baptiz$ *ild is reborn z a *ild ( light4 ,light$ c&les are plac$ 9 ! h&s ( ! baptiz$ p]sons or ( _! god-p>5ts4 ,^? ab\t to take v[s c>ry lights be=e ! *ur* (ficial & ! same idea is atta*$ to ! cu/om ( c>ry+ or ( hold+ lights on o!r occasions su* z w$d+s & fir/ communion4 ,lights are plac$ ar\nd ! bodies ( ! dead & are c>ri$ at ! fun]al4 ,!y n only protect ! dead f ! p[]s ( d>kness b !y symbolize ! dead z /ill liv+ 9 ! light ( ,*ri/4 ,! use ( light$ c&les ar\nd bodies ( ! dead /ill survives to "s ext5t among ,prote/ants1 b _! significance has be5 lo/ sight (4 ,ev5 9 ! eighte5? c5tury fun]als 9 ,engl& 7 accompani$ by light$ tap]s1 b ! c>ry+ ( lights 9 o!r processions appe>s to h ceas$ ) ! ,re=mation4 ,9 "s p>ts ( ,scotl& x is /ill ! cu/om to place two light$ c&les on a table beside a corpse on ! day ( ! fun]al4 ,) ! importance ( light 9 ! ritual ( ! *ur* x is n surpris+ t ! ext9ction ( lights is a "p ( ! c]emony ( excommunication4 ,su* a c]emony is describ$ 9 an e>ly writ+ ?us3 ,twelve prie/s %\ld /& ab\t ! bi%op1 hold+ 9 _! h&s light$ tor*es1 :i* at ! conclusion ( ! ana!ma or excommunication !y %\ld ca/ d[n & trample "u foot4 ,:5 ! excommunicant is re9/at$1 a light$ c&le is plac$ 9 8 h&s z a symbol ( reconciliation4 ,^! & _m o!r c]emonial uses ( light h be5 & are practis$1 b !y are n always m&atory4 ,fur!rmore1 ! cu/oms h v>i$ f "t to "t1 b ! few :i* h be5 t\*$ ^u illu/rate ! impressive "p t light has play$ 9 religi\s s]vices4 ,dur+ ! ,re=mation ! c]emonial use ( lights 0 greatly alt]$ & 0 aboli%$ 9 ! ,prote/ant *ur*es z a relic ( sup]/ition & papal au?ority4 ,9 ! ,lu!ran *ur*es c]emonial lights 7 l>gely reta9$1 9 ! ,*ur* ( ,engl& !y h be5 subject$ to _m *anges l>gely ?r\gh ! edicts ( ! rul]s4 ,9 ! latt] *ur* _m controv]sies 7 wag$ ov] c]emonial lights & _! use has be5 among ! indictm5ts ( a numb] ( (ficials ( ! *ur* 9 impea*m5t cases be=e ! ,h\se ( ,commons4 ,_m uses ( light 9 religi\s c]emonies 7 reviv$ 9 ca!drals aft] ! ,re/oration & !y became wide-spread 9 ,engl& 9 ! n9ete5? c5tury4 ,z late z #ahhi ! ,ar*bi%op ( ,cant]bury rul$ t c]ta9 c]emonial c&les 7 lawful accord+ to ! ,pray]-,book ( ,edw>d ,,vi1 b ! :ole "q 0 left op5 & unsettl$4 ,^! byways ( artificial light are complex & fasc9at+ because _! /udy leads into _m *annels & f> into ! obscurity ( ! *ildhood ( ! human race4 ,a glimpse ( !m is important 9 a survey ( ! influ5ce ( artificial light ^u ! progress ( civilization because 9 ^! usages ! innate & acquir$ impressiv5ess ( light is enc\nt]$4 ,al?\gh _m c]emonial uses ( light rema91 x is d\btful if _! significance & especially _! orig9 are appreciat$ by mo/ p]sons4 ,nev]!less1 no m int]e/+ phase ( artificial light is enc\nt]$ ?an ?is1 :i* rea*es to ! f\ndation ( civilization4 ,v ,,oil-,,lamps ,,( ,,! ,,n9ete5? ,,c5tury ,x w be not$ t ! light-s\rces ?r\gh\t ! e>ly ages 7 flames1 ! result ( burn+ mat]ial4 ,?is pr9ciple ( light-production has p]si/$ until ! pres5t "t1 b 9 ! latt] "p ( ! n9ete5? c5tury c]ta9 dep>tures revolutioniz$ artificial light+4 ,h[ev]1 x is n ! int5tion to ent] ! mod]n p]iod 9 ?is *apt] except 9 foll[+ ! progress ( ! oil-lamp ?r\gh its p]iod ( sci5tific developm5t4 ,! oil-lamp & ! c&le 7 ! ma9/ays ( artificial light+ ?r\gh\t _m c5turies4 ,! fats & waxes :i* ^! light-s\rces burn$ 7 _m b 9 ! lat] c5turies !y 7 *iefly tall[1 sp]m-oil1 sp]maceti1 l>d-oil1 olive-oil1 colza-oil1 bees-wax & vegetable waxes4 ,^? fuels :i* are n liquid are melt$ to liquid =m by ! heat ( ! flame be=e !y are actually consum$4 ,! c&le is ( ! latt] type & despite its pres5t l[ly place & its primitive "*1 x is really an +5i\s device4 ,its fuel rema9s conv5i5tly solid s t x is readily %ipp$ & /or$2 !re is no?+ to spill or to break beyond easy repair2 b :5 x is light$ ! heat ( its flame melts ! solid fuel & ?us x becomes an oil-lamp4 ,animal & vegetable oils 7 ma9ly us$ until ! middle ( ! n9ete5? c5tury1 :5 petroleum 0 produc$ 9 suffici5t quantities to introduce m9]al oils4 ,?is m>k$ ! beg9n+ ( an era ( developm5ts 9 oil-lamps1 b ^! 7 g5]ally ! natural (fspr+ ( e>ly developm5ts by ,ami ,arg&4 ,be=e man discov]$ t nature _h /or$ a trem5d\s supply ( m9]al oil 9 ! e>? he 0 oblig$ to hunt broadca/ = fats & waxes to supply him ) artificial light4 ,he also 0 oblig$ to endure unpleasant odors f ! crude fuels & 9 e>ly exp]im5ts ) fats & waxes ! odor 0 c>efully not$ z an important factor4 ,tall[ 0 a by-product ( ! kit*5 or ( ! but*]4 ,/e>9e1 a con/itu5t ( tall[1 is a comp\nd ( glyc]yl & /e>ic acid4 ,x is obta9$ by break+ up *emically ! glyc]ides ( animal fats & sep>at+ ! fatty acids f glyc]94 ,fats are glyc]ides2 t is1 comb9ations ( oleic1 palmetic1 & /e>ic acids4 ,inasmu* z ! =m] is liquid at ord9>y temp]atures & ! o!rs are solid1 x foll[s t ! consi/5cy or solidity ( fats dep5d ^u ! relative proportions ( ! ?ree con/itu5ts4 ,! sp]m-:ale1 :i* lives 9 ! w>m] p>ts ( all ! oceans1 has be5 hunt$ rel5tlessly = fuels = artificial light+4 ,9 its head cavities sp]m-oil 9 liquid =m is f\nd ) ! :ite waxy sub/ance kn[n z sp]maceti4 ,colza-oil is yield$ by rape-se$ & olive-oil is extract$ f ripe olives4 ,! waxes are comb9ations ( alli$ acids ) bases some:at relat$ to glyc]9 b ( complex composition4 ,fats & waxes are m or less relat$1 b to di/+ui% !m c>efully w\ld lead f> afield into ! complexities ( organic *emi/ry4 ,all ^! animal & vegetable products :i* 7 us$ z fuels = light-s\rces are ri* 9 c>bon1 :i* acc\nts = ! light-value ( _! flames4 ,! brightness ( su* a flame is due to inc&esc5t c>bon p>ticles1 b ?is phase ( light-production is discuss$ 9 ano!r *apt]4 ,^! oils1 fats1 & waxes are compos$ by weight ( ab\t #ge to #hj p] c5t4 c>bon2 #aj to #ae p] c5t4 hydrog52 & #e to #aj p] c5t4 oxyg54 ,until ! middle ( ! eighte5? c5tury ! oil-lamps 7 %all[ vessels fill$ ) animal or vegetable oil & f ^! res]voirs %ort wicks project$4 ,! flame 0 feeble & smoky & ! odors 7 sometimes v repugnant4 ,view+ su* light-s\rces f ! pres5t age 9 :i* light is pl5tiful1 conv5i5t1 & free f ! great disadvantages ( ^! e>ly oil-lamps1 x is difficult to imag9e ! possibility ( ! pres5t civilization em]g+ f t p]iod )\t be+ accompani$ by progress 9 light-production4 ,! improvem5ts made 9 ! eighte5? c5tury pav$ ! way = great] progress 9 ! foll[+ c5tury4 ,?is is ! case ?r\gh\t ! ages1 b !re are special reasons = ! trem5d\s impetus :i* light-production has exp]i5c$ 9 ! pa/ half-c5tury4 ,^! are ! acquirem5t ( sci5tific k f sy/ematic rese>* & ! application ( ?is k by organiz$ developm5t4 ,! fir/ & mo/ notable improvem5t 9 ! oil-lamp 0 made by ,arg& 9 #aghd4 ,our nation 0 j organiz+ aft] its successful /ruggle = indep5d5ce at ! "t :5 ! production ( light z a sci5ce 0 born4 ,arg& produc$ ! tubul> wick & contribut$ ! greate/ improvem5t by be+ ! fir/ to p]=m ! app>5tly simple act ( plac+ a glass *imney ^u ! lamp4 ,8 burn] consi/$ ( two conc5tric metal tubes betwe5 :i* ! wick 0 locat$4 ,! inn] tube 0 op51 s t air c\ld rea* ! inn] surface ( ! wick z well z ! out] surface4 ,! lamp *imney n only protect$ ! flame f drafts b also improv$ combu/ion by increas+ ! supply ( air4 ,x re/$ ^u a p]=at$ flange bel[ ! burn]4 ,if ! glass *imney ( a mod]n k]os5e lamp be lift$1 x w be not$ t ! flame flick]s & smokes & t x becomes /eady & smokeless :5 ! *imney is replac$4 ,! advantages ( su* a *imney are obvi\s n[1 b ,arg& = 8 a*ievem5ts is entitl$ to a place among ! great m5 :o h borne ! tor* ( civilization4 ,he took ! fir/ /ep t[>d adequate artificial light & op5$ a new era 9 light+4 ,! v>i\s improvem5ts ( ! oil-lamp a*iev$ by ,arg& comb9$ to effect complete combu/ion1 ) ! result t a /eady1 smokeless lamp ( consid]able lum9\s int5sity 0 = ! fir/ "t available4 ,_m developm5ts foll[$1 among :i* 0 a comb9ation ( res]voir & gravity fe$ :i* ma9ta9$ ! oil at a con/ant level4 ,9 lat] lamps1 ^u ! adoption ( m9]al oil1 ?is 0 f\nd unnecess>y1 p]haps ow+ to ! con/ruction ( ! wick & to ! physical *>act]i/ics ( ! oil :i* favor$ capill>y action 9 ! wick4 ,h[ev]1 ! height ( ! oil 9 ! res]voir ( mod]n oil-lamps makes "s diff]5ce 9 ! am\nt ( light emitt$4 ,! ,c>cel lamp1 :i* appe>$ 9 #ahjj1 consi/$ ( a d\ble pi/on op]at$ by clockwork4 ,?is =c$ ! oil ?r\gh a tube to ! burn]4 ,fran*ot inv5t$ ! mod]ator lamp 9 #ahcf1 :i*1 because ( its simplicity & effici5cy soon sup]s$$ _m o!r lamps design$ = burn+ animal & vegetable oils4 ,! *ief feature ( ! mod]ator lamp is a spiral spr+ :i* =ces ! oil upw>d ?r\gh a v]tical tube to ! burn]4 ,^! are /ill us$ to "s ext5t 9 ,france1 b ow+ to ! fact t me*anical lamps ev5tually 7 v g5]ally replac$ by m simple ones1 x does n appe> necess>y to describe ^! complex me*anisms 9 detail4 ,:5 coal is di/ill$ at mod]ate temp]atures1 volatile liquids are obta9$4 ,^! hydroc>bons1 be+ inflammable1 naturally attract$ att5tion :5 fir/ kn[n1 & 9 #agha _! use z fuel = lamps 0 sugge/$4 ,h[ev]1 x 0 n until #ahbj t ! light oils obta9$ by di/ill+ coal-t>1 a by-product ( ! coal-gas indu/ry :i* 0 !n 9 its e>ly /age ( developm5t1 7 burn$ to "s ext5t 9 ! ,holliday lamp4 ,9 ?is lamp ! oil is conta9$ 9 a res]voir f ! bottom ( :i* a f9e metal tube c>ries ! oil d[n to a rose-burn]4 ,! oil is heat$ by ! flame & ! vaporiz$ m9]al oil :i* escapes ?r\gh small orifices is burn$4 ,?is type ( lamp has und]gone _m physical *anges1 b its pr9ciple survives to ! pres5t "t 9 ! gasol5e & k]os5e burn]s hang+ on a pole by ! side ( ! /reet-p$dl]'s /&4 ,al?\gh petroleum products 7 n us$ to any appreciable ext5t = illum9at+-purposes until aft] ! middle ( ! n9ete5? c5tury1 m9]al oil is m5tion$ by ,h]odotus & o!r e>ly writ]s4 ,9 #ahdg petroleum 0 discov]$ 9 a coal-m9e 9 ,engl&1 b ! supply fail$ 9 a %ort "t4 ,h[ev]1 ! discov]]1 ,james ,"y1 _h f\nd t ?is oil 0 valuable z a lubricant & ^u ! failure ( ?is s\rce he began exp]im5ts 9 di/ill+ oil f %ale f\nd 9 coal deposits4 ,^! 7 de/9$ to =m ! corn]-/one ( ! oil indu/ry 9 ,scotl&4 ,9 #ahej he began produc+ petroleum 9 ?is mann]1 b x 0 n s]i\sly consid]$ = illum9at+-purposes4 ,h[ev]1 9 ,g]many ab\t ?is "t lamps 7 develop$ = burn+ ! light] di/illates & ^! 7 introduc$ into sev]al c\ntries4 ,b ! price ( ^! light] oils 0 s great t little progress 0 made until1 9 #ahei1 ,col4 ,e4 ,l4 ,drake discov]$ oil 9 ,p5nsylvania4 ,by /udy+ ! geological =mations & conclud+ t oil %\ld be obta9$ by bor+1 ,drake gave to ! _w a means ( obta9+ petroleum1 & 9 quantities :i* 7 de/9$ to r$uce ! price ( m9]al oil to a level undream$ ( !ret(ore4 ,to 8 imag9ation1 :i* saw va/ res]voirs ( oil 9 ! dep?s ( ! e>?1 ! _w owes a great debt4 ,lamps 7 import$ f ,g]many to all p>ts ( ! civiliz$ _w & ! k]os5e lamp became ! prevail+ light-s\rce4 ,hundr$s ( ,am]ican pat5ts 7 all[$ = oil-lamps & _! improvem5ts 9 ! next decade4 ,illu/ration3 ,,lamps ,,( ,a ,,c5tury ,,or ,,two ,,ago ,illu/ration3 ,,elaborate ,,fixtures ,,( ,,! ,,age ,,( ,,c&les ,! crude petroleum1 ( c\rse1 is n fit = illum9at+ purposes1 b x conta9s compon5ts :i* are satisfactory4 ,! v>i\s compon5ts are sort$ out by fractional di/illation & ! oil = burn+ 9 lamps is select$ accord+ to its volatility1 viscosity1 /ability1 etc4 ,x mu/ n be s volatile z to h a dang]\sly l[ fla%+-po9t1 nor s /able z to h9d] its burn+ well4 ,9 ?is fractional di/illation a va/ v>iety ( products are n[ obta9$4 ,gasol5e is among ! light] products1 ) a d5sity ( ab\t #j4fe2 k]os5e has a d5sity ( ab\t #j4hj2 ! lubricat+-oils f #j4he to #j4ie2 & !re are _m solids su* z vasel9e & p>aff9 :i* are widely us$ = _m purposes4 ,?is process ( ref9+ oils is n[ ! s\rce ( p>aff9 = mak+ c&les1 9 :i* x is usually mix$ ) sub/ances l /e>9 9 ord] to raise its melt+-po9t4 ,crude petroleum possesses a v repugnant odor2 x v>ies 9 color f yell[ to black2 & its specific gravity ranges f ab\t #j4hj to #a4jj1 b commonly is betwe5 #j4hj & #j4ij4 ,its *emical con/itution is *iefly ( c>bon & hydrog51 9 ! approximate ratio ( ab\t six to "o respectively4 ,x is a mixture ( p>aff9 hydroc>bons hav+ ! g5]al =mula ( ,cn,h#bn#b & ! individual memb]s ( ?is s]ies v>y f ,,*#d 7me?ane7 to ,c#ae;,h#cb 7p5tadecane71 al?\gh ! solid hydroc>bons are /ill m complex4 ,petroleum is f\nd 9 _m c\ntries & ! ,unit$ ,/ates is p>ticul>ly bless$ ) great /ores ( x4 ,! ord9>y lamp consi/+ ( a wick :i* draws up ! m9]al oil & fe$s x to a flame is effici5t & fairly free f dang]4 ,x requires c>e & may cause disa/] if x is upset1 b x has be5 blam$ unju/ly 9 _m accid5ts4 ,a disadvantage ( ! k]os5e lamp ov] electric light+1 = example1 is ! relatively great] possibility ( accid5ts ?r\gh ! c>elessness ( ! us]4 ,?is po9t is br\ght out 9 /ati/ics ( fire-insurance companies1 :i* %[ t ! fires caus$ by k]os5e lamps are mu* m num]\s ?an ^? f o!r me?ods ( light+4 ,if 9 a mod]n lamp ( prop] con/ruction a close-fitt+ wick is us$ & ! lamp is ext+ui%$ by turn+ d[n & bl[+ across ! *imney1 !re is little dang] 9 its use except+ accid5tal breakage or ov]turn+4 ,9 oil-lamps at ! pres5t "t m9]al oils are us$ :i* possess fla%+-po9ts above #ge;,f4 ,! highly volatile compon5ts ( petroleum are dang]\s because !y =m v explosive mixtures ) air at ord9>y temp]atures4 ,a m9]al oil l k]os5e1 to be us$ ) safety 9 lamps1 %\ld n be too volatile4 ,x is pref]able t an inflammable vapor %\ld n be giv5 (f at temp]atures "u #abj;,f4 ,! oil mu/ be ( su* physical *>act]i/ics z to be drawn up to ! burn] by capill>ity f ! res]voir :i* is situat$ bel[4 ,x is volatiliz$ by ! heat ( ! flame into a mixture ( hydrog5 & hydroc>bon gases & ^! are consum$ "u ! heat ( ! process ( consumption by ! oxyg5 9 ! air4 ,! result+ products ( ?is combu/ion1 if x is complete1 are c>bon dioxide & wat]-vapor4 ,= ea* c&le-p[] ( light p] h\r ab\t #j4bd cubic foot ( c>bon dioxide & #j4ah cubic foot ( wat]-vapor are =m$ by a mod]n oil-lamp4 ,t an op5 flame dev\rs some?+ f ! air is easily demon/rat$ by enclos+ x 9 an air-tight space4 ,! flame gradually becomes feeble & smoky & f9ally goes out4 ,x w be not$ t a burn+ lamp w vitiate ! atmosph]e ( a clos$ room by consum+ ! oxyg5 & return+ 9 its place c>bon dioxide4 ,?is is simil> to ! vitiation ( ! atmosph]e by brea?+ p]sons & te/s indicate t = ea* two c&le-p[] emitt$ by a k]os5e flame ! vitiation is equal to t produc$ by "o adult p]son4 ,inasmu* z oil-lamps are ord9>ily ( #aj to #bj c&le-p[]1 x is se5 t "o lamp w consume z mu* oxyg5 z sev]al p]sons4 ,9 ord] t oil-lamps may produce a brilliant light free f smoke1 combu/ion mu/ be complete4 ,! correct quantity ( oil mu/ be f$ to ! burn] & x mu/ be prop]ly vaporiz$ by heat4 ,if insuffici5t oil is f$1 ! int5sity ( ! light is dim9i%$ & if too mu* is available at ! burn]1 smoke & o!r products ( incomplete combu/ion w be emitt$4 ,! wick is an important factor1 =1 ?r\gh capill>ity1 x fe$s oil =cefully to ! burn] aga9/ ! action ( gravity4 ,?is action ( a wick is commonly look$ ^u ) indiff]5ce b 9 reality x is caus$ by an int]e/+ & really wond]ful ph5om5on4 ,wicks are usually made ( high-grade cotton fib] loosely spun into co>se ?reads & ^! are wov5 into a loose plait4 ,! wick mu/ be dry be=e be+ ins]t$ into ! burn]2 & x is desirable t x be consid]ably long] ?an is necess>y m]ely to rea* ! bottom ( ! res]voir4 ,a flame burn+ 9 ! op5 w smoke because insuffici5t oxyg5 is br\ght 9 contact ) x4 ,! injuri\s products ( ?is incomplete combu/ion are c>bon monoxide & oil vapors1 :i* are a m5ace to heal?4 ,to supply ! necess>y am\nt ( oxyg5 7air7 to ! flame1 a =c$ draft is produc$4 ,*imneys are simple means ( accompli%+ ?is1 & ?is is _! function :e!r on oil-lamps or factories4 ,o!r means ( =c$ draft h be5 us$1 su* z small fans or compress$ air4 ,9 ! railway locomotive ! %ort smoke-/ack is insuffici5t = supply+ l>ge quantities ( air to ! fire-box s ! exhau/$ /eam is all[$ to escape into ! /ack4 ,) ea* noisy puff ( smoke a quantity ( air is =cibly drawn into ! fire-box ?r\gh ! burn+ fuel4 ,9 ! mod]n oil-lamp ! ru% ( air due to ! pull ( ! *imney is brok5 & ! air is diffus$ by ! wire gauze or holes at ! base ( ! burn]4 ,^! metal p>ts1 be+ hot1 also s]ve to w>m ! oil be=e x rea*es ! burn+ end ( ! wick1 ?us s]v+ to aid vaporization & combu/ion4 ,! consumption ( oil p] c&le-p[] p] h\r v>ies consid]ably ) ! k9d ( lamp & ) ! "* ( ! oil4 ,! av]age consumption ( oil-lamps burn+ a m9]al oil ( ab\t #j4hj specific gravity & a r high fla%+-po9t is ab\t #ej to #fj grams ( oil p] c&le-p[] p] h\r = well-design$ flame-lamps4 ,k]os5e weighs ab\t #f4f p\nds p] gallon2 !re=e1 ab\t #hjj c&le-p[] h\rs p] gallon are obta9$ f mod]n lamps employ+ wicks4 ,k]os5e lamps are usually ( #aj to #bj c&le-p[]1 al?\gh !y are made up to #ajj c&le-p[]4 ,^! lum9\s int5sities ref] to ! maximum horizontal c&le-p[]4 ,! be/ practice n[ deals ) ! total light output1 :i* is express$ 9 lum5s1 & on ?is basis a consumption ( "o gallon ( k]os5e p] h\r w\ld yield ab\t #hjjj lum5s4 ,oil-lamps h be5 devis$ 9 :i* ! oil is burn$ z a spray eject$ by air-pressure4 ,^! burn ) a l>ge flame2 h[ev]1 a s]i\s feature is ! escape ( consid]able oil :i* is n burn$4 ,^! lamps are us$ 9 indu/rial light+1 especially outdoors1 & possess ! advantage ( consum+ l[-grade oils4 ,!y produce ab\t #gjj to #hjj c&le-p[] h\rs p] gallon ( oil4 ,lamps ( ?is type ( ! l>g] sizes burn ) v]tical flames two or ?ree feet high4 ,! oil is heat$ z x approa*es ! nozzle & is fairly well vaporiz$ on em]g+ into ! air4 ,! names ( ,lucig51 ,wells1 ,doty1 & o!rs are associat$ ) ?is type ( lamp or tor*1 :i* is a /ep 9 ! direction ( air-gas light+4 ,dur+ ! latt] "p ( ! n9ete5? c5tury num]\s developm5ts 7 made :i* p>allel$ ! progress 9 gas-light+4 ,exp]im5ts 7 conduct$ :i* bord]$ closely ^u ! next epo*al ev5t 9 light-production--! appe>ance ( ! gas mantle4 ,"o ( ^! 0 ! use ( plat9um gauze by ,kitson4 ,he produc$ an app>atus simil> to ! oil-spray lamp1 on a small & m delicate scale4 ,! hot blue flame 0 n v lum9\s & he attempt$ to obta9 light by heat+ a mantle ( f9e plat9um gauze4 ,al?\gh ^! mantles emitt$ a brilliant light = a few h\rs1 _! light-emissivity 0 de/roy$ by c>bonization4 ,aft] ! appe>ance ( ! ,welsba* mantle1 ,kitson's lamp & o!rs met ) success by utiliz+ x4 ,f ?is po9t1 att5tion 0 c5t]$ ^u ! new wond]1 :i* is discuss$ 9 a lat] *apt] aft] c]ta9 sci5tific pr9ciples 9 light-production h be5 discuss$4 ,! k]os5e or m9]al-oil lamp 0 a boon to light+ 9 ! n9ete5? c5tury & ev5 to-day x is a bless+ 9 _m homes1 especially 9 villages1 9 ! c\ntry1 & 9 ! remote di/ricts ( civilization4 ,its ext5sive use at ! pres5t "t is %[n by ! fact t ab\t eight million lamp-*imneys are n[ be+ manufactur$ ye>ly 9 ?is c\ntry4 ,x is conv5i5t & safe :5 c>elessness is avoid$1 & is fairly free f odor4 ,its vitiation ( ! atmosph]e may be c\nt]act$ by prop] v5tilation & !re rema9s only ! disadvantage ( keep+ x 9 ord] & ( accid5tal breakage & ov]turn+4 ,! k]os5e lant]n is widely us$ to-day1 b ! dang] due to accid5t is ev]-pres5t4 ,! consequ5ces ( su* accid5ts are (t5 s]i\s & are exemplifi$ 9 ! t]rible conflagration 9 ,*icago 9 #ahga1 :5 ,mrs4 ,o',le>y's c[ kick$ ov] a lant]n & />t$ a fire :i* burn$ ! city4 ,mod]n developm5ts 9 light+ are gradually encroa*+ ^u ! t]ritory 9 :i* ! oil-lamp has reign$ supreme = _m ye>s4 ,acetyl5e plants 7 introduc$ to a consid]able ext5t "s "t ago & to-day ! self-conta9$ home-light+ electric plant is be+ in/all$ 9 l>ge numb]s 9 ! c\ntry homes ( ! l&4 ,,vi ,,e>ly ,,gas-,,light+ ,ow+ to ! fact t ! smoky1 flick]+ oil-lamp p]si/$ ?r\gh\t ! c5turies & until ! magic t\* ( ,arg& 9 ! latt] "p ( ! eighte5? c5tury trans=m$ x into a comm5dable light-s\rce1 ! read] is prep>$ to suppose t gas-light+ is ( rec5t orig94 ,app>5tly ,william ,murdock 9 ,engl& 0 ! fir/ to in/all pipes = ! conveyance ( gas = light+ purposes4 ,9 an article 9 ! ,philosophical ,transactions ( ! ,royal ,society ( ,london dat$ ,febru>y #be1 #ahjh1 9 :i* he gives an acc\nt ( ! fir/ indu/rial gas-light+1 he /ates3 ,x is n[ ne>ly sixte5 ye>s1 s9ce1 9 a c\rse ( exp]im5ts ,i 0 mak+ at ,r$ru? 9 ,cornwall1 ^u ! quantities & qualities ( ! gases produc$ by di/illation f diff]5t m9]al & vegetable sub/ances1 ,i 0 induc$ by "s obs]vation ,i _h previ\sly made ^u ! burn+ ( coal1 to try ! combu/ible prop]ty ( ! gases produc$ f x4444 ,inasmu* z he is cr$it$ ) hav+ light$ 8 home by means ( pip$ gas1 ?is exp]im5tal in/allation may be consid]$ to h be5 made 9 #agib4 ,9 8 fir/ trial he burn$ ! gas at ! op5 ends ( ! pipes2 b f9d+ ?is wa/eful1 he clos$ ! ends & 9 ea* bor$ ?ree small holes f :i* ! gas-flames div]g$4 ,x is said t he once us$ 8 wife's ?imble 9 an em]g5cy to close ! end ( ! pipe2 &1 ! ?imble be+ mu* worn & consequ5tly conta9+ a numb] ( small holes1 t9y gas-jets em]g$ f ! holes4 ,?is incid5t is said to h l$ to ! use ( small holes 9 8 burn]s4 ,he also light$ a /reet lamp & _h bladd]s fill$ ) gas to c>ry at night1 ) :i*1 & 8 little /eam c>riage runn+ on ! road1 he us$ to a/oni% ! p4 ,app>5tly unkn[n to ,murdock1 previ\s obs]vations _h be5 made z to ! inflammability ( gas f coal4 ,long be=e ?is ,dr4 ,clayton describ$ "s obs]vations on coal-gas1 :i* he call$ ! _s ( coals4 ,he fill$ bladd]s ) ?is gas & kept !m = "s "t4 ,^u 8 prick+ "o ( !m ) a p9 & apply+ a c&le1 ! gas burn$ at ! hole4 ,?us ,clayton _h a portable gas-light4 ,he 0 l$ to exp]im5t ) di/illation ( coal f "s exp]i5ces ) gas f a natural coal b$1 & he ?us describes 8 initial laboratory exp]im5t3 ,i got "s coal1 & di/ill$ x 9 a retort 9 an op5 fire4 ,at fir/ !re came ov] only phlegm1 aft]w>ds a black oil1 & !n likewise1 a _s arose :i* ,i c\ld no ways cond5se2 b x =c$ my lute & broke my glasses4 ,once :5 x _h =c$ my lute1 com+ close !reto1 9 ord] to try to repair x1 ,i obs]v$ t ! _s :i* issu$ out caught fire at ! flame ( ! c&le1 & cont9u$ burn+ ) viol5ce z x issu$ out 9 a /ream1 :i* ,i blew out1 & light$ aga9 alt]nately sev]al times4 ,he !n turn$ 8 att5tion to sav+ "s ( ! gas & hit ^u ! use ( bladd]s4 ,he 0 surpris$ at ! am\nt ( gas :i* 0 obta9$ f a small am\nt ( coal2 =1 z he /at$1 ! _s cont9u$ to rise = sev]al h\rs1 & fill$ ! bladd]s almo/ z fa/ z a man c\ld h bl[n !m ) 8 m\?2 & yet ! quantity ( coals di/ill$ 0 inconsid]able4 ,al?\gh ?is acc\nt appe>$ 9 ! ,transactions ( ! ,royal ,society 9 #agci1 !re is /rong evid5ce t ,dr4 ,clayton _h writt5 x _m ye>s be=e1 at lea/ prior to #afia4 ,b be=e ent]+ fur!r into ! e>ly hi/ory ( gas-light+1 x is int]e/+ to inquire into ! k possess$ 9 ! sev5te5? c5tury p]ta9+ to natural & artificial gas4 ,d\btless !re are isolat$ in/ances ?r\gh\t hi/ory ( enc\nt]s ) natural gas4 ,surely obs]vant p]sons ( bygone ages h not$ a small flame emanat+ f ! end ( a /ick ^: o!r end 0 burn+ 9 a bonfire or 9 ! fireplace4 ,?is is a gas-plant on a small scale2 = ! gas is =m$ at ! burn+ end ( ! wood5 /ick & is conduct$ ?r\gh its holl[ c5t] to ! cold end1 :]e x w burn if light$4 ,if a piece ( pap] be roll$ into ! =m ( a tube & incl9$ some:at f a horizontal position1 inflammable gas w emanate f ! upp] end if ! l[] end is burn+4 ,by apply+ a mat* ne> ! upp] end1 we c ignite ?is jet ( gas4 ,h[ev]1 x is c]ta9 t little 0 kn[n ( gas = illum9at+ purposes be=e ! eighte5? c5tury4 ,! lit]ature ( an anci5t nation is (t5 ref]r$ to z reveal+ ! civilization ( ! p]iod4 ,surely ! sci5tific lit]ature :i* deals ) concrete facts is an exact indicator ( ! te*nical k ( a p]iod6 ,t little 0 kn[n ( natural gas & d\btless ( artificial gas 9 ! sev5te5? c5tury is %[n by a brief report entitl$ ,a ,well & ,e>? 9 ,lanca%ire tak+ ,fire at a ,c&le1 by ,?o4 ,%irley 9 ! ,transactions ( ! ,royal ,society 9 #affg4 ,mu* ( ! qua9t *>m ( ! orig9al is lo/ by inability to pres5t ! text 9 its orig9al =m1 b x is reproduc$ z closely z practicable4 ,! report 0 z foll[s3 ,ab\t ! latt] ,end ( ,feb4 #afei1 return+ f a ,j\rney to my ,h\se 9 ,wigan1 ,i 0 ent]ta9$ ) ! ,relation ( an odd ,spr+ situat$ 9 "o ,mr4 ,hawkley's ,gr\nd 7if ,i mi/ake n7 ab\t a ,mile f ! ,t[n1 9 t ,road :i* leads to ,w>r+ton & ,*e/]3 ,! ,p ( ?is ,t[n did confid5tly affirm1 ,t ! ,wat] ( ?is ,spr+ did burn l ,oil4 ,:5 we came to ! said ,spr+ 7be+ #e or #f 9 ,company toge!r7 & appli$ a light$ ,c&le to ! ,surface ( ! ,wat]2 !re 0 'tis true1 a l>ge ,flame sudd5ly produc$1 :i* burnt ! ,foot ( a ,tree1 gr[+ on ! ,top ( a neighb\r+ ,bank1 ! ,wat] ( :i* ,spr+ fill$ a ,dit* t 0 !re1 & cov]$ ! ,burn+-place2 ,i appli$ ! light$ ,c&le to div]s ,p>ts ( ! ,wat] conta9$ 9 ! said ,dit*1 & f\nd1 z ,i expect$1 t ^u ! ,t\* ( ! ,c&le & ! ,wat] ! ,flame 0 ext9ct4 ,aga91 hav+ tak5 up a ,di% full ( wat] at ! flam+ ,place1 & held ! light$ ,c&le to x1 x w5t out4 ,yet ,i obs]v$ t ! ,wat]1 at ! ,burn+-place1 did boil1 & heave1 l ,wat] 9 a ,pot ^u ! ,fire1 ?o' by putt+ my ,h& into x1 ,i c\ld n p]ceive x s mu* z w>m4 ,?is ,boil+ ,i conceiv$ to proce$ f ! ,eruption ( "s bitum9\s or sulphure\s ,fumes2 consid]+ ?is ,place 0 n above #cj or #dj ,y>ds di/ant f ! ,m\? ( a ,coal-,pit !re3 ,& inde$ ,wigan1 ,a%ton1 & ! :ole ,c\ntry1 = _m ,miles compass1 is und]laid ) ,coal4 ,!n1 apply+ my ,h& to ! ,surface ( ! ,burn+-place ( ! ,wat]1 ,i f\nd a /rong ,brea?1 z x 7 a ,w9d1 to be> aga9/ my ,h&4 ,:5 ! ,wat] 0 dra9$ away1 ,i appli$ ! ,c&le to ! ,surface ( ! dry ,e>?1 at ! same ,po9t :]e ! ,wat] burn$ be=e2 ! ,fumes took fire1 & burn$ v bright & vigor\s4 ,! ,cone ( ! ,flame asc5d$ a ,foot & a half f ! ,sup]ficies ( ! ,e>?2 & ! ,basis ( x 0 ( ! ,compass ( a ,man's ,hat ab\t ! ,brims4 ,i !n caus$ a ,bucket full ( ,wat] to be p\r'd on ! ,fire1 by :i* x 0 pres5tly qu5*$4 ,i did n p]ceive ! ,flame to be discol\r$ l t ( sulphur\s ,bodies1 nor to h any manife/ ,sc5t ) x4 ,! ,fumes1 :5 !y broke out ( ! ,e>?1 & press'd aga9/ my ,h&1 7 n1 to my be/ ,remembrance1 at all hot4 ,turn+ aga9 to ,dr4 ,clayton's exp]im5ts1 we see t he po9t$ out /rik+ & valuable prop]ties ( coal-gas b app>5tly gave no att5tion to its useful purposes4 ,fur!rmore1 8 acc\nt appe>s to h attract$ no p>ticul> notice at ! "t ( its publication 9 #agci4 ,dr4 ,ri*>d ,watson 9 #agfg describ$ ! results ( exp]im5ts :i* he _h be5 mak+ ) ! products aris+ f ! di/illation ( coal4 ,9 8 process he p]mitt$ ! gas to asc5d ?r\gh curv$ tubes1 & he p>ticul>ly not$ its great inflammability z well z ela/icity4 ,he also obs]v$ t x reta9$ ! =m] prop]ty aft] x _h pass$ ?r\gh a great quantity ( wat]4 ,8 publi%$ acc\nt dealt ) a v>iety ( facts & computations p]ta9+ to ! quantities ( coke1 t>1 etc41 produc$ f diff]5t k9ds ( coal & 0 a sci5tific "w ( value1 b app>5tly ! usefulness ( ! prop]ty ( inflammability ( coal-gas did n occur to him4 ,x is usually ! habit ( ! sci5tific explor] ( nature to return f excursions into h] unfrequ5t$ recesses ) new k1 to place x ^u exhibition1 & to return = m4 ,! inv5tor passes by & sees applications = "s ( ^! sci5tific trophies :i* are productive ( mom5t\s consequ5ces to mank9d4 ,sir ,humphrey ,davy describ$ 8 primitive arc-lamp ?ree qu>t]s ( a c5tury be=e ,bru% develop$ an arc-lamp = practical purposes4 ,maxwell & ,h]tz respectively pr$ict$ & produc$ electromagnetic waves long be=e ,m>coni appli$ ?is k & develop$ wireless telegraphy4 ,9 a simil> mann] sci5tific acc\nts ( ! production & prop]ties ( coal-gas ant$at$ by _m ye>s ! initial applications made by ,murdock to illum9at+ purposes4 ,up to ! beg9n+ ( ! n9ete5? c5tury ! civiliz$ _w _h only a fa9t glimpse ( ! illum9at+ prop]ty ( gas1 b practicable gas-light+ 0 de/9$ soon to be an epo*al ev5t 9 ! progress ( light+4 ,! dawn ( mod]n sci5ce 0 co9cid5t ) ! dawn ( a lum9\s era4 ,at ,soho f\ndry 9 #agih ,murdock con/ruct$ an app>atus :i* enabl$ him to exhibit 8 light+-plan on a l>g] scale & to exp]im5t on purify+ & burn+ ! gas s z to elim9ate odor & smoke4 ,soho 0 an unique in/itution describ$ z a place to :i* m5 ( g5ius 7 invit$ & resort$ f e civiliz$ c\ntry1 to ex]cise & to display _! tal5ts4 ,! p]fection ( ! manufactur+ arts 0 ! great & con/ant aim ( its lib]al & enlight5$ proprietors1 ,messrs4 ,b\lton & ,watt2 & :oev] resid$ !re 0 surr\nd$ by a circle ( sci5tific1 +5i\s1 & skilful m51 at all times ready to c>ry into effect ! inv5tions ( ea* o!r4 ,! ,treaty ( ,ami5s1 :i* gave to ,engl& ! peace %e 0 sorely 9 ne$ (1 af=d$ ,murdock an opportunity 9 #ahjb favorable = mak+ a public display ( gas-light+4 ,! illum9ation ( ! ,soho works on ?is occasion is describ$ z "o ( extraord9>y spl5d\r4 ,! fronts ( ! ext5sive range ( build+s 7 ornam5t$ ) a l>ge numb] ( devices :i* display$ ! v>iety ( =ms ( gas-lights4 ,at t "t ?is 0 a lum9\s spectacle ( great novelty & ! populace came f f> & wide to gaze at1 & to admire1 ?is wond]ful display ( ! comb9$ effects ( sci5ce & art4 ,naturally1 ,murdock _h _m difficulties to ov]come 9 ^! e>ly days1 b he possess$ skill & p]sev]ance4 ,8 fir/ retorts = di/ill+ coal 7 simil> to ! common glass retort ( ! *emi/4 ,next he tri$ ca/-iron cyl9d]s plac$ p]p5dicul>ly 9 a common furnace1 & 9 ea* 7 put ab\t fifte5 p\nds ( coal4 ,9 #ahjd he con/ruct$ !m ) doors at ea* end1 = fe$+ coal & extract+ coke respectively1 b ^! 7 f\nd inconv5i5t4 ,9 8 fir/ light+ in/allation 9 ! factory ( ,phillips & ,lee 9 #ahje he us$ a l>ge retort ( ! =m ( a bucket ) a cov] on x4 ,inside he in/all$ a loose cage ( grat+ to hold ! coal4 ,:5 c>bonization 0 complete ! coke c\ld be remov$ z a :ole by extract+ ?is cage4 ,?is retort _h a capacity ( fifte5 hundr$ p\nds ( coal4 ,he labor$ ) me*anical details1 v>i$ ! size & %ape ( ! retorts1 & exp]im5t$ ) diff]5t temp]atures1 ) ! result t he laid a solid f\ndation = coal-gas light+4 ,= 8 a*ievem5ts he is entitl$ to an honorable place among ! tor*-be>]s ( civilization4 ,! epo*al feature ( ! developm5t ( gas-light+ is t "h 0 a possibility = ! fir/ "t ( provid+ light+ z a public utility4 ,9 ! e>ly ye>s ( ! n9ete5? c5tury ! f\ndation 0 laid = ! great public-utility organizations ( ! pres5t "t4 ,fur!rmore1 gas-light+ 0 an improvem5t ov] c&les & oil-lamps f ! /&po9ts ( conv5i5ce1 safety1 & co/4 ,! latt] po9ts are emphasiz$ by ,murdock 9 8 pap] pres5t$ be=e ! ,royal ,society 9 #ahjh1 9 :i* he describes ! fir/ indu/rial in/allation ( gas-light+4 ,he us$ two types ( burn]s1 ! ,arg& & ! cockspur4 ,! =m] resembl$ ! ,arg& lamp 9 "s respects & ! latt] 0 a ?ree-flame burn] sugge/+ a fleur-de-lis4 ,9 ?is in/allation !re 7 #bga ,arg& burn]s & #fcf cockspurs4 ,ea* ( ! =m] gave a light equal to t ( f\r c&les2 & ea* ( ! latt]1 a light equal to two & a qu>t] ( ! same c&les2 mak+ !re=e ! total ( ! gas light a little m ?an #bejj c&les4 ,! c&le to :i* he ref]s 0 a mold c&le ( six 9 ! p\nd & its light 0 consid]$ a /&>d ( lum9\s int5sity :5 x 0 consum+ tall[ at ! rate ( #j4d oz4 7#age gra9s7 p] h\r4 ,?us ! c&le became v e>ly a /&>d light-s\rce & has p]si/$ z su* 7) c]ta9 v>iations 9 ! specifications7 until ! pres5t "t4 ,h[ev]1 dur+ rec5t ye>s o!r /&>d light-s\rces h be5 devis$4 ,accord+ to ,murdock1 ! ye>ly co/ ( gas-light+ 9 ?is initial case 0 #fjj p\nds /]l+ aft] all[+ g5]\sly = int]e/ on capital inve/$ & depreciation ( ! app>atus4 ,! co/ ( furni%+ ! same am\nt ( light by means ( c&les he comput$ to be #bjjj p\nds /]l+4 ,?is comp>ison 0 on ! basis ( an av]age ( two h\rs ( artificial light+ p] day4 ,on ! basis ( ?ree h\rs ( artificial light+ p] day1 ! relative co/ ( gas-& c&le-light+ 0 ab\t "o to five4 ,murdock 0 *>act]i/ically mode/ 9 discuss+ 8 a*ievem5ts & 8 foll[+ /atem5t %\ld be read ) ! conditions ( ! ye> #ahjh 9 m9d3 ,! peculi> s(tness & cle>ness ( ?is light ) its almo/ unv>y+ int5sity1 h br\ght x into great fav\r ) ! "w p4 ,& its be+ free f ! inconv5i5ce & dang]1 result+ f sp>ks & frequ5t snuff+ ( c&les1 is a circum/ance ( mat]ial importance1 z t5d+ to dim9i% ! haz>d ( fire1 to :i* cotton mills are kn[n to be expos$4 ,al?\gh ?is in/allation 9 ! mill ( ,phillips & ,lee is ! fir/ "o describ$ by ,murdock1 9 reality x is n ! fir/ indu/rial gas-light+ in/allation4 ,dur+ ! developm5t ( gas app>atus at ! ,soho works & aft] 8 lum9\s display 9 #ahjb1 he gradually ext5d$ gas-light+ to all ! pr9cipal %ops4 ,h[ev]1 ?is 9 a s5se 0 exp]im5tal "w4 ,o!rs 7 apply+ _! k & +5uity to ! problem ( mak+ gas-light+ practicable1 b ,murdock has be5 aptly t]m$ ! fa!r ( gas-light+4 ,among ! pione]s 0 ,le ,bon 9 ,france1 ,be*] 9 ,muni*1 & ,w9zl] or ,w9sor1 a ,g]man :o 0 attract$ to ! possibilities ( gas-light+ by an exhibition :i* ,le ,bon gave 9 ,p>is 9 #ahjb4 ,w9sor le>n$ t ,le ,bon _h be5 grant$ a pat5t 9 ,p>is 9 #agii = mak+ an illum9at+ gas f wood & tri$ to obta9 ! rights = ,g]many4 ,be+ unsuccessful 9 ?is1 he set ab\t to le>n ! secrets ( ,le ,bon's process1 :i* he did1 p]haps l>gely ow+ to an accumulation ( in=mation directly f ! inv5tor dur+ ! negotiations4 ,w9sor !n turn$ to ,engl& z a f]tile field = ! exploitation ( gas-light+ & aft] conduct+ exp]im5ts 9 ,london = "s "t he made plans to organize ! ,national ,heat & ,light ,co4 ,w9sor 0 prim>ily a promot]1 ) little or no te*nical k2 = 9 8 claims & adv]tisem5ts he disreg>d$ facts ) a facility possess$ only by ! ignorant4 ,he boa/$ ( 8 inv5tions & discov]ies 9 ! mo/ hyp]bolical language1 :i* 0 b\nd to provoke a controv]sy4 ,nev]!less1 he 0 clev] & 9 #ahjc he publicly exhibit$ 8 plan ( light+ by means ( coal-gas at ! ,lyceum ,!atre 9 ,london4 ,he gave lectures accompani$ by int]e/+ & in/ructive exp]im5ts & 9 ?is mann] attract$ ! public to 8 exhibition4 ,all ?is "t he 0 promot+ 8 company1 b 8 promot+ in/9ct caus$ 8 repres5tations to be extravagant & deceptive1 :i* expos$ him to ! ridicule & suspicion ( le>n$ m54 ,8 attempt to obta9 c]ta9 exclusive rights by ,act ( ,p>liam5t fail$ because ( opposition ( sci5tific m5 t[>d 8 claims & ( ! /& :i* ,murdock ju/ly made 9 self-protection4 ,^! ye>s ( controv]sy yield ent]ta9+ lit]ature = ^? :o *oose to read x1 b un=tunately space does n p]mit dwell+ ^u x4 ,! inve/igations by committees ( ,p>liam5t also af=d amus+ side-lights4 ,?r\gh\t all ?is ,murdock appe>$ mode/ & cons]vative & _h ! support ( reputable sci5tific m51 b ,w9sor ma9ta9$ extravagant claims4 ,dur+ "o ( ^! inve/igations ,sir ,humphrey ,davy 0 exam9$ by a committee f ! ,h\se ( ,commons 9 #ahji4 ,he refut$ ,w9sor's claims = a sup]ior coke z a by-product & /at$ t ! production ( gas by ! di/illation ( coal _h be5 well kn[n = ?irty or =ty ye>s & ! production ( t> z long4 ,he /at$ t x 0 ! op9ion ( ! ,c\ncil ( ! ,royal ,society t ,murdock 0 ! fir/ p]son to apply coal-gas to light+ 9 actual practice4 ,z secret>y ( ! ,society1 ,sir ,humphrey ,davy /at$ t at ! la/ session x _h be/[$ ! ,c\nt ,rum=d m$al ^u ,murdock = 8 economical application ( ! gas light4 ,w9sor proce$$ to float 8 company )\t await+ ! ,act ( ,p>liam5t & 9 #ahjg light$ a /reet 9 ,pall ,mall4 ,?r\gh ! opposition :i* he ar\s$1 & ow+ to ! j claims ( priority on ! "p ( ,murdock1 ! bill to incorporate ! ,national ,heat & ,light ,co4 ) a capital ( #bjj1jjj p\nds /]l+ 0 ?r[n out4 ,h[ev]1 he succe$$ 9 #ahab 9 receiv+ a *>t] v mu* modifi$ 9 =m1 = ! ,*>t]$ ,gas ,light & ,coke ,co4 :i* 0 ! =]unn] ( ! pres5t ,london ,gas ,light & ,coke ,co4 ,! conditions impos$ ^u ?is company z pres5t$ 9 an e>ly treatise on gas-light+ 7by ,accum 9 #ahah7 7 z foll[s3 ,! p[] & au?orities grant$ to ?is corporate body are v re/rict$ & mod]ate4 ,! individuals compos+ x h no exclusive privilege2 _! *>t] does n prev5t o!r p]sons f ent]+ into competition ) !m4 ,_! op]ations are conf9$ to ! metropolis1 :]e !y are b\nd to furni% n only a /rong] & bett] light to su* /reets & p>i%es z *use to be light$ ) gas1 b also at a *eap] price ?an %all be paid = light+ ! said /reets ) oil 9 ! usual mann]4 ,! corporation is n p]mitt$ to traffic 9 ma*9]y = manufactur+ or convey+ ! gas into private h\ses1 _! capital or jo9t /ock is limit$ to #bjj1jjj1 & 8 ,maje/y has ! p[] ( decl>+ ! gas-light *>t] void if ! company fail to fulfil ! t]ms ( x4 ,! progress ( ?is e>ly company 0 sl[ at fir/1 b ) ! appo9tm5t ( ,samuel ,clegg z eng9e] 9 #ahac an era ( te*nical developm5ts began4 ,new /ations 7 built & _m improvem5ts 7 introduc$4 ,by improv+ ! me?ods ( purify+ ! gas a great advance 0 made4 ,! utility ( gas-light+ grew apace z ! prejudices disappe>$1 b = a long "t ! /ock ( ! company sold at a price f> bel[ p>4 ,ab\t ?is "t ! fir/ gas explosion took place & ! memb]s ( ! ,royal ,society set a prec$5t :i* has liv$ & ?riv$3 !y appo9t$ a committee to make an inquiry4 ,b app>5tly ! inquiry 0 ( "s value1 = x l$ to "s useful alt]ations & new modifications 9 its app>atus & ma*9]y4 ,_m improvem5ts 7 be+ introduc$ dur+ ^! ye>s & "o ( !m 9 #ahaf increas$ ! gase\s product f coal by di/ill+ ! t> :i* 0 obta9$ dur+ ! fir/ di/illation4 ,9 #ahaf ,clegg obta9$ a pat5t = a horizontal rotat+ retort2 = an app>atus = purify+ coal-gas ) cream ( lime2 & = a rotative gas-met]4 ,be=e progress+ too f>1 we mu/ m5tion ! e>ly "w ( ,william ,h5ry4 ,9 #ahjd he describ$ publicly a me?od ( produc+ coal-gas4 ,besides mak+ exp]im5ts on production & utilization ( coal-gas = light+1 he devot$ 8 k ( *emi/ry to ! analysis ( ! gas4 ,he also made analytical /udies ( ! relative value ( wood1 peat1 oil1 wax1 & diff]5t k9ds ( coal = ! di/illation ( gas4 ,8 *emical analyses %[$ to a consid]able ext5t ! prop]ties ( c>buret$ hydrog5 ^u :i* illum9at+ value dep5d$4 ,! results ( 8 "w 7 publi%$ 9 v>i\s ,engli% j\rnals betwe5 #ahje & #ahbe & !y contribut$ mu* to ! advancem5t ( gas-light+4 ,al?\gh ,clegg's orig9al gas-met] 0 complicat$ & cumb]some1 x prov$ to be a useful device4 ,9 fact1 x appe>s to h be5 ! mo/ orig9al & b5eficial inv5tion occasion$ by e>ly gas-light+4 ,lat] ,samuel ,crosley greatly improv$ x1 ) ! result t x 0 introduc$ to a consid]able ext5t2 b by no means 0 x univ]sally adopt$4 ,ano!r improvem5t made by ,clegg at ?is "t 0 a device :i* ma9ta9$ ! pressure ( gas approximately con/ant reg>dless ( ! pressure 9 ! gasomet] or tank4 ,clegg retir$ f ! s]vice ( ! gas company 9 #ahag aft] a record ( accompli%m5ts :i* glorifies 8 "n 9 ! annals ( gas-light+4 ,murdock is und\bt$ly entitl$ to ! di/9ction ( hav+ be5 ! fir/ p]son :o appli$ gas-light+ to l>ge private e/abli%m5ts1 b ,clegg ov]came _m difficulties & 0 ! fir/ to illum9ate a :ole t[n by ?is means4 ,9 ,london 9 #ahag ov] #cjj1jjj cubic feet ( coal-gas 0 be+ manufactur$ daily1 an am\nt suffici5t to op]ate #gf1ejj ,arg& burn]s yield+ #f c&le-p[] ea*4 ,gas-light+ 0 n[ excit+ great int]e/ & 0 firmly e/abli%$4 ,we/m9/] ,bridge 0 light$ by gas 9 #ahac1 & ! /reets ( ,we/m9/] dur+ ! foll[+ ye>4 ,gas-light+ became popul> 9 ,london by #ahaf & 9 ! c\rse ( ! next few ye>s x 0 adopt$ by ! *ief cities & t[ns 9 ! ,unit$ ,k+dom & on ! ,cont95t4 ,x f\nd its way into ! h\ses r sl[ly at fir/1 ow+ to appreh5sion ( ! att5dant dang]s1 to ! lack ( purification ( ! gas1 & to ! indiff]5t s]vice4 ,x 0 n until ! latt] half ( ! n9ete5? c5tury t x 0 g5]ally us$ 9 resid5ces4 ,! gas-burn] fir/ employ$ by ,murdock receiv$ ! "n cockspur f ! %ape ( ! flame4 ,?is _h an illum9at+ value equival5t to ab\t "o c&le = ea* cubic foot ( gas burn$ p] h\r4 ,! next /ep 0 to flatt5 ! weld$ end ( ! gas-pipe & to bore a s]ies ( holes 9 a l9e4 ,f ! %ape ( ! flames ?is =m ( burn] receiv$ ! "n cockscomb4 ,x 0 some:at m effici5t ?an ! cockspur burn]4 ,! next obvi\s /ep 0 to slit ! end ( ! pipe by means ( a f9e saw4 ,f ?is slit ! gas 0 burn$ z a %eet ( flame call$ ! bats-w+4 ,9 #ahbj ,nielson made a burn] :i* all[$ two small jets to collide & ?us =m a flat flame4 ,! effici5cy ( ?is fi%-tail burn] 0 some:at high] ?an t ( ! e>li] ones4 ,its flame 0 /eadi] because x 0 less influ5c$ by drafts ( air4 ,9 #ahec ,frankl& %[$ an ,arg& burn] consi/+ ( a metal r+ conta9+ a s]ies ( holes f :i* jets ( gas issu$4 ,! glass *imney surr\nd$ ^!1 ano!r *imney1 ext5d+ some:at l[]1 surr\nd$ ! :ole1 & a glass plate clos$ ! bottom4 ,! air to be f$ to ! gas-jets came d[nw>d betwe5 ! two *imneys & 0 heat$ be=e x rea*$ ! burn]4 ,?is increas$ ! effici5cy by r$uc+ ! am\nt ( cool+ at ! burn] by ! air requir$ = combu/ion4 ,?is improvem5t 0 9 reality ! =]unn] ( ! reg5]ative lamps :i* 7 develop$ lat]4 ,9 #ahed ,b[dit* br\ght out a reg5]ative lamp &1 ow+ to ! excessive publicity :i* ?is lamp obta9$1 he is g5]ally cr$it$ ) ! inception ( ! reg5]ative burn]4 ,?is pr9ciple 0 adopt$ 9 sev]al lamps :i* came into use lat]4 ,!y 7 all bas$ ^u ! pr9ciple ( heat+ bo? ! gas & ! air requir$ = combu/ion prior to _! rea*+ ! burn]4 ,! burn] is some?+ l an inv]t$ ,arg& arrang$ to produce a circul> flame project+ d[nw>d ) a c5tral cusp4 ,! air- & gas-passages are directly above ! flame & are heat$ by x4 ,9 #ahgi ,fri$ri* ,siem5s br\ght out a lamp ( ?is type :i* 0 adapt$ f a device orig9ally design$ = heat+ purposes1 ow+ to ! sup]ior light :i* 0 produc$4 ,?is 0 ! be/ gas-lamp up to t "t4 ,lat]1 ,w5ham1 ,crom>tie1 & o!rs pat5t$ lamps op]at+ on ?is same pr9ciple4 ,murdock e>ly modifi$ ! ,arg& burn] to meet ! requirem5ts ( burn+ gas & by us+ ! *imney obta9$ bett] combu/ion & a /eadi] flame ?an f ! op5 burn]s4 ,he & o!rs recogniz$ t ! temp]ature ( ! flame _h a consid]able effect ^u ! am\nt ( light emitt$ & non-conduct+ mat]ial su* z /eatite 0 sub/itut$ = ! metal1 :i* cool$ ! flame by conduct+ heat f x4 ,^! 7 ! e>ly /eps :i* l$ f9ally to ! reg5]ative burn]4 ,! increas+ effici5cy ( ! v>i\s gas-burn]s is indicat$ by ! foll[+1 :i* are approximately ! c&le-p[] bas$ ^u equal rates ( consumption1 namely1 "o cubic foot ( gas p] h\r3 ,c&le-p[] p] cubic foot ( gas p] h\r ,fi%-tail flames1 dep5d+ ^u size #j4f to #b4e ,arg&1 dep5d+ ^u improvem5ts #b4i to #c4e ,reg5]ative #g to #aj ,x is se5 t ! possibilities ( gas light+ 7 recogniz$ 9 sev]al c\ntries1 all ( :i* contribut$ to its developm5t4 ,"s ( ! e>li] acc\nts h be5 drawn *iefly f ,engl&1 b ^! are int5d$ m]ely to s]ve z examples ( ! difficulties enc\nt]$4 ,d\btless1 simil> controv]sies arose 9 o!r c\ntries 9 :i* pione]s 7 also nurs+ gas-light+ to maturity4 ,h[ev]1 x is c]ta9 t mu* ( ! e>ly progress ( light+ ( ?is "* 0 fa!r$ 9 ,engl&4 ,gas-light+ 0 de/9$ to become a ?riv+ indu/ry1 & is ( su* importance 9 light+ t ano!r *apt] is giv5 its mod]n developm5ts4 ,,vii ,,! ,,sci5ce ,,( ,,light-,,production ,9 previ\s *apt]s mu* ( ! hi/orical developm5t ( artificial light+ has be5 pres5t$ & sev]al subjects h be5 trac$ to ! mod]n p]iod :i* m>ks ! beg9n+ ( an int5sive attack by sci5ti/s ^u ! problems p]ta9+ to ! production ( effici5t & adequate light-s\rces4 ,_m hi/orical ev5ts rema9 to be t\*$ ^u 9 lat] *apt]s1 b x is necess>y at ?is po9t = ! read] to become acqua9t$ ) c]ta9 g5]al physical pr9ciples 9 ord] t he may read ) great] int]e/ "s ( ! *apt]s :i* foll[4 ,x is se5 t f a /&po9t ( artificial light+1 ! d>k age ext5d$ well into ! n9ete5? c5tury4 ,oil-lamps & gas-light+ began to be s]i\sly develop$ at ! beg9n+ ( ! la/ c5tury1 b ! pione]s gave att5tion *iefly to me*anical details & some:at to ! *emi/ry ( ! fuels4 ,x 0 n until ! sci5ce ( physics 0 appli$ to light-s\rces t rapid progress 0 made4 ,all ! light-s\rces us$ ?r\gh\t ! ages1 & ne>ly all mod]n ones1 radiate light by virtue ( ! inc&esc5ce ( solids or ( solid p>ticles & x is an int]e/+ fact t c>bon is g5]ally ! solid :i* emits light4 ,?is is due to v>i\s physical *>act]i/ics ( c>bon1 ! *ief "o be+ its extremely high melt+-po9t4 ,h[ev]1 mo/ practicable light-s\rces ( ! pa/ & pres5t may be divid$ into two g5]al classes3 7#a7 ,^? 9 :i* solids or solid p>ticles are heat$ by _! own combu/ion1 & 7#b7 ^? 9 :i* ! solids are heat$ by "s o!r means4 ,"s light-s\rces include bo? pr9ciples & "s p]haps _c be includ$ "u ei!r pr9ciple )\t qualification4 ,! lum9\s flames ( burn+ mat]ial su* z ^? ( wood-spl9t]s1 c&les1 oil-lamps1 & gas-jets1 & ! gl[+ emb]s ( burn+ mat]ial appe> 9 ! fir/ class2 & inc&esc5t gas-mantles1 electric filam5ts1 & arc-lamps to "s ext5t are repres5tative ( ! second class4 ,c]ta9 flam+ arcs involve bo? pr9ciples1 b ! light ( ! firefly1 phosphoresc5ce1 & inc&esc5t gas 9 vacuum tubes _c be includ$ 9 ?is simplifi$ classification4 ,! /atus ( ^! w become cle> lat]4 ,x has be5 se5 t flames h be5 prom95t s\rces ( artificial light2 & al?\gh ( l[ lum9\s effici5cy1 !y /ill h mu* to comm5d !m f ! /&po9ts ( portability1 conv5i5ce1 & subdivision4 ,! mat]ials :i* h be5 burn$ = light1 :e!r solid or liquid1 are ri* 9 c>bon1 & ! solid p>ticles ( c>bon by virtue ( _! inc&esc5ce are responsible = ! brightness ( a flame4 ,a jet ( pure hydrog5 gas w burn v hot b ) s l[ a brightness z to be b>ely visible4 ,if solid p>ticles are inject$ into ! flame1 mu* m light usually w be emitt$4 ,a gas-burn] ( ! ,buns5 type1 9 :i* complete combu/ion is obta9$ by mix+ air 9 prop] proportions ) ! gas1 gives a hot flame :i* is ( a pale blue color4 ,^u ! clos+ ( ! orifice ?r\gh :i* air is admitt$1 ! flame becomes bright & smoky4 ,! flame is n[ less hot1 z indicat$ by ! pres5ce ( smoke or c>bon p>ticles1 & combu/ion is n complete4 ,h[ev]1 x is bright] because ! solid p>ticles ( c>bon 9 pass+ upw>d ?r\gh ! flame become heat$ to temp]atures at :i* !y gl[ & ea* becomes a m9iature s\rce ( light4 ,a close obs]v] w notice t ! flame f a mat*1 a c&le1 or a gas-jet1 is n uni=mly bright4 ,! read] may v]ify ?is by light+ a mat* & obs]v+ ! flame4 ,!re is always a blui% or d>k] portion ne> ! bottom4 ,9 ?is less lum9\s "p ! air is comb9+ ) ! hydrog5 ( ! hydroc>bon :i* is be+ vaporiz$ & dis9tegrat$4 ,ev5 ! flame ( a c&le or ( a burn+ spl9t] is a m9iature gas-plant1 = ! solid or liquid hydroc>bons are vaporiz$ be=e be+ burn$4 ,ow+ to ! incom+ cold] air at ?is po9t1 ! flame is n hot en\gh = complete combu/ion4 ,! unburn$ c>bon p>ticles rise 9 its draft & become heat$ to inc&esc5ce1 ?us acc\nt+ = ! bright] portion4 ,9 cases ( complete combu/ion !y are ev5tually oxidiz$ into c>bon dioxide be=e !y are able to escape4 ,if a piece ( metal be held 9 ! flame1 x imm$iately becomes cov]$ ) soot or c>bon1 because x has r$uc$ ! temp]ature bel[ ! po9t at :i* ! *emical reaction--! unit+ ( c>bon ) oxyg5--w cont9ue4 ,an ord9>y flat gas-flame ( ! bats-w+ type may v>y 9 temp]ature 9 its c5tral portion f #cjj;,f4 at ! bottom to ab\t #cjjj;,f4 at ! top4 ,! c5tral portion lies betwe5 two hott] lay]s 9 :i* ! v]tical v>iation is n s great4 ,! brightness ( ! upp] portion is due to inc&esc5t c>bon =m$ 9 ! l[] "p4 ,:5 sci5ti/s le>n$ by explor+ flames t brightness 0 due to ! radiation ( light by inc&esc5t solid matt]1 ! way 0 op5 = _m exp]im5ts4 ,9 ! e>ly days ( gas-light+ inve/igations 7 made to det]m9e ! relation ( illum9at+ value to ! *emical con/itution ( ! gas4 ,! results comb9$ ) a k ( ! necessity = solid c>bon 9 ! flame l$ to improvem5ts 9 ! gas = light+ purposes4 ,gas ri* 9 hydroc>bons :i* 9 turn are ri* 9 c>bon is high 9 illum9at+ value4 ,heat+-effect dep5ds ^u heat-units1 s ! rat+ ( gas 9 calories or o!r heat-units p] cubic foot is :olly satisfactory only = gas us$ = heat+4 ,! *emical con/itution is a bett] indicator ( illum9at+ value4 ,z sci5tific k increas$1 ef=ts 7 made to get solid matt] into ! flames ( light-s\rces4 ,in/ead ( conf9+ ef=ts to ! c>bon cont5t ( ! gas1 solid mat]ials 7 actually plac$ 9 ! flame1 & 9 ?is mann] v>i\s inc&esc5t burn]s 7 develop$4 ,a piece ( lime plac$ 9 a hydrog5 flame or t ( a ,buns5 burn] is se5 to become hot & to gl[ brilliantly4 ,by produc+ a hott] flame by means ( ! bl[pipe1 9 :i* hydrog5 & oxyg5 are consum$1 ! piece ( lime 0 rais$ to a high] temp]ature & a m int5se light 0 obta9$4 ,9 ,p>is !re 0 a s]i\s attempt at /reet-light+ by ! use ( buttons ( zirconia heat$ 9 an oxyg5-coal-gas flame1 b x prov$ unsuccessful ow+ to ! rapid det]ioration ( ! buttons4 ,?is 0 ! l9e ( exp]im5tation :i* l$ to ! developm5t ( ! lime-light4 ,! inc&esc5t burn] 0 widely employ$1 & until ! use ( electricity became common ! lime-light 0 ! ma9/ay = ! /age & = ! projection ( lant]n slides4 ,x is 9 use ev5 to-day = "s purposes4 ,! orig9 ( ! phrase 9 ! lime-light is obvi\s4 ,! lum9\s int5sity ( ! oxyhydrog5 lime-light z us$ 9 practice 0 g5]ally f #bjj to #djj c&le-p[]4 ,! light decreases rapidly z ! burn] is us$1 if a new surface ( lime is n pres5t$ to ! flame f "t to "t4 ,at ! high temp]atures ! lime is some:at volatile & ! surface seems to *ange 9 radiat+ p[]4 ,zirconium oxide has be5 f\nd to s]ve bett] ?an lime4 ,improvem5ts 7 made 9 gas-burn]s 9 ord] to obta9 hott] flames into :i* solid matt] c\ld be introduc$ to obta9 bright light4 ,_m mat]ials 7 us$1 b obvi\sly !y 7 limit$ to ^? ( a fairly high melt+-po9t4 ,lime1 magnesia1 zirconia1 & simil> oxides 7 us$ successfully4 ,if ! read] w\ld c>e to try an exp]im5t 9 v]ification ( ?is simple pr9ciple1 let him take a piece ( magnesium ribbon su* z is us$ 9 light+ = photography & ignite x 9 a ,buns5 flame4 ,if x is held c>efully :ile burn+1 a ribbon ( a% 7magnesia7 w be obta9$ intact4 ,plac+ ?is 9 ! fa9tly lum9\s flame1 he w be surpris$ at ! brilliance ( its inc&esc5ce :5 x has become heat$4 ,! simple exp]im5t indicates ! possibilities ( light-production 9 ?is direction4 ,naturally1 metals ( high melt+-po9t su* z plat9um 7 tri$ & a network ( plat9um wire1 9 reality a plat9um mantle1 came into practical use 9 ab\t #ahhj4 ,! t[n ( ,nantes 0 light$ by gas-burn]s us+ ^! plat9um-gauze mantles1 b ! mantles 7 unsuccessful ow+ to _! rapid det]ioration4 ,?is l9e ( exp]im5tation f9ally bore fruit ( imm5se value = f x ! gas-mantle evolv$4 ,a gr\p ( s-call$ r>e-e>?s1 among :i* are zirconia1 ?oria1 c]ia1 erbia1 & yttria 7^! are oxides ( zirconium1 etc47 possess a numb] ( int]e/+ *emical prop]ties "s ( :i* h be5 utiliz$ to advantage 9 ! developm5t ( mod]n artificial light4 ,!y are :ite or yell[i%-:ite oxides ( a highly refractory "* f\nd 9 c]ta9 r>e m9]als4 ,mo/ ( !m are v brilliant :5 heat$ to a high temp]ature4 ,?is latt] feature is easily expla9$ if ! nature ( light & ! radiat+ prop]ties ( sub/ances are consid]$4 ,suppose pieces ( diff]5t sub/ances1 = example1 glass & lime1 are heat$ 9 a ,buns5 flame to ! same temp]ature :i* is suffici5tly great to cause bo? ( !m to gl[4 ,not)/&+ ! id5tical conditions ( heat+1 ! glass w be only fa9tly lum9\s1 :ile ! piece ( lime w gl[ brilliantly4 ,! =m] is a poor radiator2 fur!rmore1 ! lime radiates a relatively great] p]c5tage ( its total en]gy 9 ! =m ( lum9\s en]gy4 ,! latt] po9t w become cle>] if ! read] w refre% 8 memory reg>d+ ! nature ( light4 ,any lum9\s s\rce su* z ! sun1 a c&le flame1 or an inc&esc5t lamp is s5d+ =? electromagnetic waves n unlike ^? us$ 9 wireless telegraphy except+ t !y are ( mu* %ort] wave-l5g?4 ,! eye is capable ( record+ "s ( ^! waves z light j z a receiv+ /ation is tun$ to record a range ( wave-l5g?s ( electromagnetic en]gy4 ,! electromagnetic waves s5t =? by a light-s\rce l ! sun are n all visible1 t is1 all ( !m d n ar\se a s5sation ( light4 ,^? t d comprise ! visible spectrum & ! diff]5t wave-l5g?s ( visible radiant en]gy manife/ !mselves by ar\s+ ! s5sations ( ! v>i\s spectral colors4 ,! radiant en]gy ( %orte/ wave-l5g? p]ceptible by ! visual app>atus excites ! s5sation ( violet & ! longe/ ones ! s5sation ( deep r$4 ,betwe5 ^! two extremes ( ! visible spectrum1 ! *ief spectral colors are blue1 gre51 yell[1 orange1 & r$ 9 ! ord] ( increas+ wave-l5g?s4 ,electromagnetic en]gy radiat$ by a light-s\rce 9 waves ( too great wave-l5g? to be p]ceiv$ by ! eye z light is t]m$ z a class infra-r$ radiant en]gy4 ,^? too %ort to be p]ceiv$ z light are t]m$ z a class ultraviolet radiant en]gy4 ,a solid body at a high temp]ature emits electro-magnetic en]gy ( all wave-l5g?s1 f ! %orte/ ultra-violet to ! longe/ infra-r$4 ,ano!r complication arises 9 ! v>iation 9 visibility or lum9osity ( en]gy ( wave-l5g?s )9 ! range ( ! visible spectrum4 ,obvi\sly1 no am\nt ( en]gy incapable ( excit+ ! s5sation ( light w be visible4 ,! en]gy ( ^? wave-l5g?s ne> ! ends ( ! visible spectrum w be ineffici5t 9 produc+ light4 ,t en]gy :i* excites ! s5sation ( yell[-gre5 produces ! greate/ lum9osity p] unit ( en]gy & is ! mo/ effici5t light4 ,! visibility or lum9\s effici5cy ( radiant en]gy may be rang$ approximately 9 ?is mann] accord+ to ! colors ar\s$3 yell[-gre51 yell[1 gre51 orange1 blue-gre51 r$1 blue1 deep r$1 violet4 ,newton1 an ,engli% sci5ti/1 fir/ describ$ ! discov]y ( ! visible spectrum & ?is is ( su* fundam5tal importance 9 ! sci5ce ( light t ! fir/ p>agraph ( 8 orig9al pap] 9 ! ,transactions ( ! ,royal ,society ( ,london is quot$ z foll[s3 ,9 ! ,ye> #afff 7at :i* "t ,i appli$ my self to ! ,gr9d+ ( ,optick ,glasses ( o!r ,figures ?an ,sph]ical7 ,i procur$ me a ,triangul> ,glass-,prism1 to try !re) ! celebrat$ ,pha5om5a ( ,col\rs4 ,& 9 ord] !reto1 hav+ d>k5$ my ,*amb]1 & made a small ,hole 9 my ,w9d[-,%uts1 to let 9 a conv5i5t ,quantity ( ! ,sun's ,light1 ,i plac$ my ,prism at its ,entrance1 t x might be !reby refract$ to ! opposite ,wall4 ,x 0 at fir/ a v pleas+ ,div]tisem5t1 to view ! vivid & int5se ,col\rs produc$ !reby2 b aft] a :ile apply+ my self to consid] !m m circumspectly1 ,i became surpris$ to see !m 9 an oblong ,=m2 :i*1 accord+ to ! receiv'd ,law ( ,refractions1 ,i expect$ %\ld h be5 circul>4 ,!y 7 t]m9at$ at ! ,sides ) /reight ,l9es1 b at ! ,ends ! ,decay ( ,light 0 s gradual1 t x 0 difficult to det]m9e ju/ly :at 0 ! ,figure1 yet !y seem$ ,semicircul>4 ,ev5 ,newton c\ld n h _h ! fa9te/ idea ( ! great developm5ts :i* 7 to be bas$ ^u ! spectrum4 ,n[ to return to ! peculi> prop]ty ( r>e-e>? oxides--namely1 _! unusual brilliance :5 heat$ 9 a flame--x is easy to und]/& ! reason = ?is4 ,= example1 :5 a numb] ( sub/ances are heat$ to ! same temp]ature !y may radiate ! same am\nt ( en]gy & /ill diff] consid]ably 9 brightness4 ,_m sub/ances are selective 9 _! absorb+ & radiat+ prop]ties4 ,"o may radiate m lum9\s en]gy & less infra-r$ en]gy1 & = ano!r ! rev]se may be true4 ,! =m] w\ld appe> bright] ?an ! latt]4 ,! sci5tific work] 9 light-production has be5 se>*+ = su* selective radiators ^: o!r prop]ties are satisfactory4 ,! r>e-e>?s possess ! prop]ty ( selectivity & are =tunately highly refractory4 ,welsba* us$ ^! 9 8 mantle1 ^: effici5cy is due p>tly to ?is selective prop]ty4 ,rec5t "w indicates t mu* high] effici5cies ( light-production are /ill atta9able by ! pr9ciples involv$ 9 ! gas-mantle4 ,turn+ aga9 to flames1 ano!r int]e/+ physical ph5om5on is se5 on plac+ solutions ( diff]5t *emical salts 9 ! flame4 ,= example1 if a piece ( asbe/os is soak$ 9 sodium *loride 7common salt7 & is plac$ 9 a ,buns5 flame1 ! pale-blue flame sudd5ly becomes lum9\s & ( a yell[ color4 ,if ?is is repeat$ ) o!r salts1 a *>act]i/ic color w be not$ 9 ea* case4 ,! yell[ flame is *>act]i/ic ( sodium & if x is exam9$ by means ( a spectroscope1 a brilliant yell[ l9e 79 fact1 a d\ble l9e7 w be se54 ,?is =ms ! basis ( spectrum analysis z appli$ 9 *emi/ry4 ,e elem5t has its *>act]i/ic spectrum consi/+ usually ( l9es1 b ! complexity v>ies ) ! elem5ts4 ,! spectra ( elem5ts also exhibit l9es 9 ! ultra-violet region :i* may be /udi$ ) a photographic plate1 ) a photo-electric cell1 & by o!r means4 ,_! spectral l9es or b&s also ext5d into ! infra-r$ region & "h !y are /udi$ by means ( ! bolomet] or o!r app>atus = detect+ radiant en]gy by ! heat :i* x produces ^u be+ absorb$4 ,spectrum analysis is f> m s5sitive ?an ! f9e/ weigh+ balance1 = if a gra9 ( salt be dissolv$ 9 a b>rel ( wat] & an asbe/os /rip be soak$ 9 ! wat] & held 9 a ,buns5 flame1 ! yell[ color *>act]i/ic ( sodium w be detectable4 ,a wond]ful example ( ! possibilities ( ?is me?od is ! discov]y ( helium 9 ! sun be=e x 0 f\nd on e>?6 ,its spectral l9es 7 detect$ 9 ! sun's spectrum & c\ld n be acc\nt$ = by any kn[n elem5t4 ,h[ev]1 x %\ld be /at$ t ! spectrum ( an elem5t diff]s g5]ally ) ! mann] obta9$4 ,! electric sp>k1 ! arc1 ! electric dis*>ge 9 a vacuum tube1 & ! flame are ! means usually employ$4 ,! spectrum has be5 dwelt ^u at "s l5g? because x is ( great importance 9 light-production & probably w figure /rongly 9 future developm5ts4 ,al?\gh 9 light+ little use has be5 made ( ! injection ( *emical salts into ord9>y flames1 x appe>s c]ta9 t su* developm5ts w\ld h ris5 if electric illum9ants _h n ent]$ ! field4 ,h[ev]1 ! pr9ciple has be5 appli$ ) great success 9 arc-lamps4 ,9 ! fir/ arc-lamps pla9 c>bon electrodes 7 us$1 b 9 "s ( ! late/ c>bon-arcs1 electrodes ( c>bon impregnat$ ) v>i\s salts are employ$4 ,= example1 calcium fluoride gives a brilliant yell[ light :5 us$ 9 ! c>bons ( ! flame arc4 ,^! are describ$ 9 detail lat]4 ,foll[+ ?is pr9ciple ( light-production ! vacuum tubes 7 develop$4 ,crookes /udi$ ! light f v>i\s gases by enclos+ !m 9 a tube :i* 0 pump$ out until a l[ vacuum 0 produc$4 ,on connect+ a high voltage to electrodes 9 ea* end1 an electrical dis*>ge pass$ ?r\gh ! residual gas mak+ x lum9\s4 ,! diff]5t gases %[ _! *>act]i/ic spectra & _! desirability z light-produc]s is at once evid5t4 ,h[ev]1 ! mo/ g5]al pr9ciple ( light-production at ! pres5t "t is ! radiation ( bodies by virtue ( _! temp]ature4 ,if a piece ( wire be heat$ by electricity1 x w become v hot be=e x becomes lum9\s4 ,at ?is temp]ature x is emitt+ only invisible infra-r$ en]gy & has an effici5cy ( z]o z a produc] ( light4 ,z x becomes hott] x beg9s to appe> r$1 b z its temp]ature is rais$ x appe>s orange1 until if x c\ld be heat$ to ! temp]ature ( ! sun1 ab\t #aj1jjj;,f41 x w\ld appe> :ite4 ,all ?is "t its lum9\s effici5cy is increas+1 because x is radiat+ n only an increas+ p]c5tage ( visible radiant en]gy b an increas+ am\nt ( ! mo/ effective lum9\s en]gy4 ,b ev5 :5 x appe>s :ite1 a l>ge am\nt ( ! en]gy :i* x radiates is invisible infra-r$ & ultra-violet1 :i* are ineffective 9 produc+ light1 s at be/ ! sub/ance at ?is high temp]ature is ineffici5t z a light-produc]4 ,9 ?is bran* ( ! sci5ce ( light-production sub/ances are s\ght n only = _! high melt+-po9t1 b = _! ability to radiate selectively z mu* visible en]gy z possible & ( ! mo/ lum9\s "*4 ,h[ev]1 at be/ ! pres5t me?od ( utiliz+ ! temp]ature radiation ( hot bodies has limitations4 ,! lum9\s effici5cies ( light-s\rces to-day are /ill v l[1 b great advances h be5 made 9 ! pa/ half-c5tury4 ,!re mu/ be "s radical dep>tures if ! effici5cy ( light-production is to rea* a mu* high] figure4 ,a good deal has be5 said ( ! firefly & ( phosphoresc5ce4 ,^! light-s\rces appe> to emit only visible en]gy &1 !re=e1 are effici5t z radiators ( lum9\s radiant en]gy4 ,b mu* rema9s to be une>!d conc]n+ !m be=e !y w be g5]ally applicable to light+4 ,if ultra-violet radiation is all[$ to imp+e ^u a phosphoresc5t mat]ial1 x w gl[ ) a consid]able brightness b w be cool to ! t\*4 ,a sub/ance ( ! same brightness by virtue ( its temp]ature w\ld be hot2 h5ce phosphoresc5ce is said to be cold light4 ,an acqua9tance ) c]ta9 t]ms is necess>y if ! read] is to und]/& c]ta9 p>ts ( ! text4 ,! e>ly c&le gradually became a /&>d1 & uni=m c&les are /ill satisfactory /&>ds :]e high accuracy is n requir$4 ,_! lum9\s int5sity & illum9at+ value became units j z ! foot 0 arbitr>ily adopt$ z a unit ( l5g?4 ,! int5sity ( o!r light-s\rces 0 repres5t$ 9 t]ms ( ! numb] ( c&les or fraction ( a c&le :i* gave ! same am\nt ( light4 ,b ! lum9\s int5sity ( ! c&le 0 tak5 only 9 ! horizontal direction4 ,9 ! same mann] ! lum9\s int5sities ( light-s\rces until a %ort "t ago 7 express$ 9 c&les z measur$ 9 a c]ta9 direction4 ,inc&esc5t lamps 7 rat$ 9 t]ms ( mean horizontal c&les1 :i* w\ld be satisfactory if ! lum9\s int5sity 7 ! same 9 all directions1 b x is n4 ,!re=e1 ! c&le-p[] 9 "o direction does n give a measure ( ! total light-output4 ,if a s\rce ( light has a lum9\s int5sity ( "o c&le 9 all directions1 ! illum9ation at a di/ance ( "o foot 9 any direction is said to be a foot-c&le4 ,?is is ! unit ( illum9ation int5sity4 ,a lum5 is ! quantity ( light :i* falls on "o squ>e foot if ! int5sity ( illum9ation is "o foot-c&le4 ,x is se5 t ! area ( a sph]e ) a radius ( "o foot is #d pi or #ab4eg squ>e feet2 !re=e1 a light-s\rce hav+ a lum9\s int5sity ( "o c&le 9 all directions emits #ab4eg lum5s4 ,?is is ! satisfactory unit1 = x measures total quantity ( light1 & lum9\s effici5cies may be express$ 9 t]ms ( lum5s p] watt1 lum5s p] cubic foot ( gas p] h\r1 etc4 ,( c\rse1 ! effici5cies ( light-s\rces are usually ( int]e/ to ! consum] if !y are express$ 9 t]ms ( co/4 ,b f a practical po9t ( view !re are _m elem5ts :i* comb9e to make ano!r important factor1 namely1 satisfactor9ess4 ,!re=e1 ! effici5cy ( artificial light+ f ! /&po9t ( ! consum] %\ld be ! ratio ( satisfactor9ess to co/4 ,h[ev]1 ! sci5ti/ is int]e/$ *iefly 9 ! effici5cy ( ! light-s\rce :i* may be express$ 9 lum5s p] watt1 or ! am\nt ( light obta9$ f a giv5 rate ( consumption or ( emission ( en]gy4 ,?is me?od ( rat+ light-s\rces p5alizes ^? radiat+ consid]able en]gy :i* does n produce ! s5sation ( light or :i* at be/ is ( wave-l5g?s t are ineffici5t 9 ?is respect4 ,t radiant en]gy :i* is :olly ( a wave-l5g? ( maximum visibility1 or1 9 o!r words1 excites ! s5sation ( yell[-gre51 is ! mo/ effici5t 9 produc+ lum9\s s5sation4 ,( c\rse1 no illum9ants are available :i* approa* ?is !oretical ideal & x is n likely t ?is w\ld be a practical ideal4 ,"u mono*romatic yell[-gre5 light ! magical drap]y ( color w\ld disappe> & ! surr\nd+s w\ld be a mono*rome ( %ades ( ?is hue4 ,hav+ no colors ) :i* to contra/ ?is color1 ! _w w\ld be colorless4 ,?is %\ld be obvi\s :5 x is consid]$ t an object :i* is r$ "u an illum9ant conta9+ all colors su* z sunlight w\ld be black or d>k gray "u mono*romatic yell[-gre5 light4 ,! r$ "u pres5t conditions is kept alive by contra/ ) o!r colors1 because ! latt] live by virtue ( ! fact t mo/ ( our pres5t illum9ants conta9 _! hues4 ,x is assum$ t ! read] kn[s t a r$ object1 = example1 appe>s r$ because x reflects 7or transmits7 r$ rays & absorbs ! o!r rays 9 ! illum9ant4 ,9 o!r words1 color is due to selective absorption reflection1 or transmission4 ,p]haps ! ideal illum9ant1 :i* is mo/ g5]ally satisfactory = g5]al activities1 is a :ite light correspond+ to noon sunlight4 ,if ?is is *os5 z ! sci5tific ideal1 ! illum9ants ( ! pres5t "t are mu* m effici5t ?an if ! mo/ effici5t light is ! ideal4 ,! lum9\s effici5cy ( ! radiant en]gy mo/ effici5t 9 produc+ ! s5sation ( light 7yell[-gre57 is ab\t #fbe lum5s p] watt4 ,t is1 if en]gy ( ?is wave-l5g? alone 7 radiat$ by a hypo!tical light-s\rce1 ea* watt w\ld produce #fbe lum5s4 ,! lum9\s effici5cy ( ! mo/ effici5t :ite light is ab\t #bfe lum5s p] watt2 9 o!r words1 if a hypo!tical light-s\rce radiat$ en]gy ( only ! visible wave-l5g?s & 9 proportions to produce ! s5sation ( :ite1 ea* watt w\ld produce #bfe lum5s4 ,if su* a :ite light 7 obta9$ by pure temp]ature radiation--t is1 by a normal radiator at a temp]ature ( #aj1jjj;,f41 :i* is impracticable at pres5t--! lum9\s effici5cy w\ld be ab\t #ajj lum5s p] watt4 ,! normal radiator :i* emits en]gy by virtue ( its temp]ature )\t selectively radiat+ m or less en]gy 9 any "p ( ! spectrum ?an indicat$ by ! !oretical radiation laws is call$ a black-body or normal radiator4 ,mod]n illum9ants h lum9\s effici5cies rang+ f #e to #cj lum5s p] watt1 s x is se5 t mu* is to be done be=e ! limit+ effici5cies are rea*$4 ,! am\nt ( light obta9$ f v>i\s gas-burn]s = ea* cubic foot ( gas consum$ p] h\r v>ies = op5 gas-flames f #e to #cj lum5s2 = ,arg& burn]s f #ce to #dj lum5s2 = reg5]ative lamps f #ej to #ge lum5s2 & = gas-mantles f #bjj to #bej lum5s4 ,9 ! developm5t ( light-s\rces1 ( c\rse1 any h>mful effects ( gases =m$ by burn+ or *emical action mu/ be avoid$4 ,"s ( ! fumes f arcs are h>mful1 b no comm]cial arc appe>s to be dang]\s :5 us$ z x is int5d$ to be us$4 ,gas-burn]s rob ! atmosph]e ( oxyg5 & vitiate x ) gases1 :i*1 h[ev]1 are h>mless if combu/ion is complete4 ,t adequate v5tilation is necess>y :]e oxyg5 is be+ consum$ is evid5t f ! data pres5t$ by au?orities on hygi5e4 ,a /&>d c&le :5 burn+ vitiates ! air 9 a room almo/ z mu* z an adult p]son4 ,an ord9>y k]os5e lamp vitiates ! atmosph]e z mu* z a half-doz5 p]sons4 ,an ord9>y s+le mantle burn] causes z mu* vitiation z two or ?ree p]sons4 ,9 ord] to obta9 a bird's-eye view ( progress 9 light-production1 ! foll[+ table ( relative lum9\s effici5cies ( sev]al light-s\rces is giv5 9 r\nd numb]s4 ,^! effici5cies are 9 t]ms ( ! mo/ effici5t 7yell[-gre57 light4 ,effici5cy 9 p] c5t4 ,sp]m-c&le #j4jb ,op5 gas-flame 4#jd ,inc&esc5t gas-mantle 4#ai ,c>bon filam5t lamp 4#je ,vacuum ,mazda lamp #a4c ,gas-fill$ ,mazda lamp #b to #c ,arc-lamps #b to #g ,:ite light radiat$ by black-body #af ,mo/ effici5t :ite light #dj ,firefly #ie ,mo/ effici5t light 7yell[-gre57 #ajj ,! lum9\s effici5cy ( a light-s\rce is di/+ui%$ f t ( a lamp4 ,! =m] is ! ratio ( ! light produc$ to ! am\nt ( en]gy radiat$ by ! light-s\rce4 ,! latt] is ! ratio ( ! light produc$ to ! total am\nt ( en]gy consum$ by ! device4 ,9 o!r words1 ! lum9\s effici5cy ( a lamp is less ?an t ( ! light-s\rce because ! consumption ( en]gy 9 o!r p>ts ( ! lamp besides ! light-s\rce are tak5 into acc\nt4 ,^! additional losses are appreciable 9 ! me*anisms ( arc-lamps b are almo/ negligible 9 vacuum inc&esc5t filam5t lamps4 ,!y are unkn[n = ! firefly1 s t its lum9\s effici5cy only z a light-s\rce c be det]m9$4 ,its effici5cy z a light+-plant may be & p]haps is r l[4 ,,viii ,,mod]n ,,gas-,,light+ ,z has be5 se51 ! light+ indu/ry1 z a public s]vice1 0 born 9 ,london ab\t a c5tury ago & companies to s]ve ! public 7 organiz$ on ! ,cont95t %ortly aft]4 ,f ?is e>ly beg9n+ gas-light rema9$ = a long "t ! only illum9ant suppli$ by a public-s]vice company4 ,x has be5 se5 t ?r\gh\t ! ages little advance 0 made 9 light+ until oil-lamps 7 improv$ by ,arg& 9 ! eighte5? c5tury4 ,c&les & op5-flame oil-lamps 7 9 use :5 ! ,pyramids 7 built & ^! 7 common until ! approa* ( ! n9ete5? c5tury4 ,9 fact1 sev]al decades pass$ aft] ! fir/ gas-light+ 0 in/all$ be=e ?is =m ( light+ began to displace ! improv$ oil-lamps & c&les4 ,x 0 n until ab\t #ahej t x began to invade ! homes ( ! middle & poor] classes4 ,dur+ ! fir/ half ( ! n9ete5? c5tury ! total light 9 an av]age home 0 less ?an is n[ obta9$ f a s+le light-s\rce us$ 9 resid5ces2 /ill1 ! total co/ ( light+ a resid5ce has decreas$ consid]ably4 ,if ! social & indu/rial activities ( mank9d are visualiz$ = ^! v>i\s p]iods 9 p>allel ) ! developm5t ( artificial light+1 a close relation is evid5t4 ,did artificial light advance m]ely h& 9 h& ) sci5ce1 inv5tion1 comm]ce1 & indu/ry1 or did x illum9ate ! pa?way8 ,al?\gh gas-light+ 0 born 9 ,engl& x soon began to receive att5tion else:]e4 ,9 #ahae ! fir/ attempt to provide a gas-works 9 ,am]ica 0 made 9 ,philadelphia2 b progress 0 sl[1 ) ! result t ,baltimore & ,new ,york l$ 9 ! erection ( gas-works4 ,!re are on record _m prote/s aga9/ proposals :i* meant progress 9 light+4 ,^! are amus+ n[1 b !y indicate ! in]tia ( ! p 9 su* matt]s4 ,:5 ,bollman 0 project+ a plan = light+ ,philadelphia by means ( pip$ gas1 a gr\p ( prom95t citiz5s submitt$ a prote/ 9 #ahcc :i* aim$ to %[ t ! consequ5ces ( ! use ( gas 7 appall+4 ,b ?is prote/ fail$ & 9 #ahce a gas-plant 0 f\nd$ 9 ,philadelphia4 ,?us gas-light+1 :i* to ,sir ,walt] ,scott 0 a pe/il5tial innovation project$ by a madman1 wea!r$ its e>ly difficulties & grew to be a mighty indu/ry4 ,cont9u$ improvem5ts & increas+ output n only alt]$ ! c\rse ( civilization by increas$ & adequate light+ b !y r$uc$ ! co/ ( light+ ov] ! span ( ! n9ete5? c5tury to a small fraction ( its initial co/4 ,?9k ( ! city ( ,philadelphia 9 #ahjj1 ) a population ( ab\t fifty ?\s&1 dep5d5t = its light+ :olly ^u c&les & oil-lamps6 ,wa%+ton's bir?day anniv]s>y 0 celebrat$ 9 #ahag ) a gr& ball att5d$ by five hundr$ ( ! lite4 ,an old report ( ! occasion /ates t ! room 0 light$ by two ?\s& wax-c&les4 ,! co/ ( ?is light+ 0 a hundr$ times ! co/ ( z mu* light = a simil> occasion at ! pres5t "t4 ,c "o imag9e ! pres5t complex activities ( a city l ,philadelphia ) ne>ly two million inhabitants to exi/ "u ! light+ conditions ( a c5tury ago8 ,to-day !re are m ?an fifty ?\s& /reet lamps 9 ! city--"o = ea* inhabitant ( a c5tury ago4 ,( ^! /reet lamps ab\t tw5ty-five ?\s& burn gas4 ,?is s+le in/ance is repres5tative ( gas-light+ :i* initiat$ ! light age & nurs$ x ?r\gh ! vicissitudes ( y\?4 ,! consumption ( gas has gr[n 9 ! ,unit$ ,/ates dur+ ?is "t to ?ree billion cubic feet p] day4 ,= /rictly illum9at+ purposes 9 #aiaj ne>ly "o hundr$ billion cubic feet 7 us$4 ,?is c\ntry has be5 bless$ ) l>ge supplies ( natural gas2 b z ?is fails new oil-fields are con/antly be+ discov]$1 s t z f> z raw mat]ials are conc]n$ ! future ( gas-light+ is assur$ = a long "t to come4 ,! adv5t ( ! gas-mantle is responsible = ! survival ( gas-light+1 because :5 x appe>$ electric lamps _h already be5 inv5t$4 ,^! 7 de/9$ to become ! =midable light-s\rces ( ! approa*+ c5tury & )\t ! gas-mantle gas-light+ w\ld n h prosp]$4 ,au] von ,welsba* 0 conduct+ a spectroscopic /udy ( ! r>e-e>?s :5 he 0 confront$ ) ! problem ( heat+ ^! sub/ances4 ,he imm]s$ cotton 9 solutions ( ^! salts z a v>iation ( ! regul> means = /udy+ elem5ts by inject+ !m into flames4 ,aft] burn+ ! cotton he f\nd t he _h a replica ( ! orig9al fabric compos$ ( ! oxide ( ! metal1 & ?is gl[$ brilliantly :5 left 9 ! flame4 ,?is gave him ! idea ( produc+ a mantle = illum9at+ purposes & 9 #ahhe he plac$ su* a mantle 9 comm]cial use4 ,8 fir/ mantles 7 unsatisfactory1 b !y 7 improv$ 9 #ahhf by ! use ( ?oria1 an oxide ( ?orium1 9 conjunction ) o!r r>e-e>? oxides4 ,8 mantle 0 n[ n only /rong] b x gave m light4 ,lat] he greatly improv$ ! mantles by purify+ ! oxides & f9ally a*iev$ 8 great triumph by add+ a slight am\nt ( c]ia1 an oxide ( c]ium4 ,welsba* is des]v+ ( a great deal ( cr$it = 8 ext5sive "w1 :i* ov]came _m difficulties & f9ally gave to ! _w a durable mantle t greatly increas$ ! am\nt ( light previ\sly obta9able f gas4 ,! physical *>act]i/ics ( a mantle dep5d ^u ! fabric & ^u ! r>e-e>?s us$4 ,x mu/ n %r9k unduly :5 burn$1 & ! a% %\ld rema9 por\s4 ,x has be5 f\nd t a mantle 9 :i* ?oria is us$ alone is a poor light-s\rce1 b t :5 a small am\nt ( c]ia is add$ ! mantle gl[s brilliantly4 ,by exp]im5t x 0 det]m9$ t ! be/ proportions = ! r>e-e>? cont5t are "o "p ( c]ia & n9ety-n9e p>ts ( ?oria4 ,great] or less proportions ( c]ia decreas$ ! light-output4 ,! actual p]c5tage ( ^! oxides 9 ! a% ( ! mantle is ab\t #aj p] c5t41 mak+ ! cont5t ( c]ia ab\t "o "p 9 "o ?\s&4 ,mantles are made by knitt+ cyl9d]s ( cotton or ( o!r fib] & soak+ ^! 9 a solution ( ! nitrates ( c]ium & ?orium4 ,"o end ( ! cyl9d] is !n sew$ toge!r ) asbe/os ?read1 :i* also provides ! loop = support+ ! mantle ov] ! burn]4 ,aft] ! mantle has dri$ 9 prop] =m1 x is burn$2 ! organic matt] disappe>s & ! nitrates are conv]t$ into oxides4 ,aft] ?is burn+ (f has be5 accompli%$ & any residual black5+ is remov$1 ! mantle is dipp$ into collodion1 :i* /r5g!ns x = %ipp+ & h&l+4 ,! collodion is a solution ( gun-cotton 9 alcohol & e!r to :i* an oil su* z ca/or-oil has be5 add$ to prev5t excessive %r9kage on dry+4 ,! mat]ials & /ructure ( ! fabric ( mantles h be5 subject$ to mu* /udy4 ,cotton 0 fir/ us$2 !n ramie fib]s 7 introduc$4 ,! ramie mantle 0 f\nd to possess a great] life ?an ! cotton mantle4 ,lat] ! mantles 7 m]c]iz$ by imm]sion 9 ammonia-wat] & ?is process yield$ a /rong] mat]ial4 ,! late/ developm5t is ! use ( an artificial silk z ! base fabric1 :i* results 9 a mantle sup]ior to previ\s mantles 9 /r5g?1 flexibility1 p]man5ce ( =m1 & p]man5ce ( lum9\s prop]ty4 ,?is artificial silk mantle w p]mit ( h&l+ ev5 aft] x has be5 9 use = sev]al hundr$ h\rs4 ,?is great advance appe>s to be due to ! fact t aft] ! artificial-silk fib]s h be5 burn$ (f1 ! fib]s are solid & cont9u\s in/ead ( por\s z 9 previ\s mantles4 ,! color-value ( ! light f mantles may be v>i$ consid]ably by alt]+ ! proportions ( ! r>e-e>?s4 ,! yell[ness ( ! light has be5 trac$ to c]ia1 s by v>y+ ! proportions ( c]ia1 ! color ( ! light may be influ5c$4 ,! inv]t$ mantle introduc$ great] possibilities into gas-light+4 ,! light c\ld be direct$ d[nw>d ) ease & _m units su* z inv]t$ b[ls 7 develop$4 ,9 fact1 ! light+-fixtures & ! light+-effects obta9able kept pace ) ^? ( electric light+1 not)/&+ ! great] difficulties enc\nt]$ by ! design] ( gas-light+ fixtures4 ,_m problems 7 enc\nt]$ 9 design+ an inv]t$ burn] op]at+ on ! ,buns5 pr9ciple1 b !y 7 f9ally satisfactorily solv$4 ,9 rec5t ye>s a great deal ( /udy has be5 giv5 to ! effici5cy ( gas-burn]s1 ) ! result t a high level ( developm5t has be5 rea*$4 ,sev]al me?ods ( electrical ignition h be5 evolv$ :i* 9 g5]al employ ! electric sp>k4 ,electrical ignition & developm5ts ( remote control h add$ great improvem5ts especially to /reet-light+ by means ( gas4 ,gas-valves = remote control are actuat$ by gas pressure & by electromagnets4 ,9 g5]al1 ! gas-light+ eng9e]s h kept pace m>vel\sly ) electric light+1 :5 _! h&icaps are consid]$4 ,v>i\s types ( burn]s h appe>$ :i* aim$ to burn m gas 9 a giv5 "t "u a mantle & !reby to increase ! output ( light4 ,^! l$ to ! developm5t ( ! pressure sy/em 9 :i* ! pressure ( gas 0 at fir/ sev]al times great] ?an usual4 ,! gas is f$ into ! mix+ tube "u ?is high] pressure 9 a mann] :i* also draws 9 an adequate am\nt ( air4 ,9 ?is way ! combu/ion at ! burn] is =c$ beyond ! po9t rea*$ ) ! usual pressure4 ,ord9>y gas pressure is equal to t ( a few in*es ( wat]1 b high-pressure sy/ems employ pressures z great z sixty in*es ( wat]4 ,"u ?is high-pressure sy/em1 mantle-burn]s yield z high z #ejj lum5s p] cubic foot ( gas p] h\r4 ,! fuels = gas-light+ are natural gas1 c>buret$ wat]-gas1 & coal-gas obta9$ by di/ill+ coal1 b !re are diff]5t me?ods ( produc+ ! artificial gases4 ,coal-gas is produc$ analytically by di/ill+ c]ta9 k9ds ( coal1 b wat]-gas & produc]-gas are made syn!tically by ! action ( sev]al con/itu5ts ^u "o ano!r4 ,c>buret$ wat]-gas is made f fix$ c>bon1 /eam1 & oil & also f /eam & oil4 ,produc]-gas is made by ! action ( /eam or air or bo? ^u fix$ c>bon4 ,wat]-gas made f /eam & oil is usually limit$ to ^? places :]e ! raw mat]ials are readily available4 ,! composition ( a gas det]m9es its heat+ & illum9at+ values1 & con/itu5ts favorable to "o are n necess>ily favorable to ! o!r4 ,coal-gas usually is ( l[] illum9at+ value ?an c>buret$ wat]-gas4 ,x conta9s m hydrog51 = example1 ?an wat]-gas & x is well kn[n t hydrog5 gives little light on burn+4 ,x has be5 se5 9 a previ\s *apt] t ! di/illation ( gas f coal = illum9at+ purposes began 9 ! latt] "p ( ! eighte5? c5tury4 ,f ?is beg9n+ ! manufacture ( coal-gas has be5 develop$ to a great & complex indu/ry4 ,! me?od is ess5tially de/ructive di/illation4 ,! coal is plac$ 9 a retort & :5 x rea*es a temp]ature ( ab\t #gjj;,f4 ?r\gh heat+ by an outside fire1 ! coal beg9s to fuse & hydroc>bon vapors beg9 to emanate4 ,^! are g5]ally p>aff9s & olef9s4 ,z ! temp]ature increases1 ^! hydroc>bons beg9 to be affect$4 ,! *emical comb9ations :i* h long exi/$ are brok5 up & !re are re>rangem5ts ( ! atoms ( c>bon & hydrog54 ,! actual *emical reactions become v complex & are some:at %r\d$ 9 unc]ta9ty4 ,9 ?is la/ /age ! illum9at+ & heat+ values ( ! gas are det]m9$4 ,usually ab\t f\r h\rs are all[$ = ! complete di/illation ( ! gase\s & liquid products f a *>ge ( coal4 ,_m int]e/+ *emical problems arise 9 ?is process & ! influ5ces ( temp]ature & "t _c be discuss$ )9 ! scope ( ?is book4 ,besides ! coal-gas1 v>i\s by-products are obta9$ dep5d+ ^u ! raw mat]ials1 ^u ! proc$ure1 & ^u ! m>ket4 ,aft] ! coal-gas is produc$ x mu/ be purifi$ & ! sulphuret$ hydrog5 at lea/ mu/ be remov$4 ,"o me?od ( accompli%+ ?is is by wa%+ ! gas ) wat] & ammonia1 :i* also removes "s ( ! c>bon dioxide & hydrocyanic acid4 ,v>i\s o!r undesirable con/itu5ts are remov$ by *emical means1 dep5d+ ^u ! conditions4 ,! purifi$ gas is n[ deliv]$ to ! gas-hold]2 b1 ( c\rse1 all ?is "t ! pressure is gov]n$1 9 ord] t ! pressure 9 ! ma9s w be ma9ta9$ con/ant4 ,mu* att5tion has be5 giv5 to ! enri*m5t ( gas = illum9at+ purposes2 t is1 to produce a gas ( high illum9at+ value f *eap fuel or by inexp5sive processes4 ,?is has be5 done by decompos+ ! t> obta9$ dur+ ! di/illation ( coal & add+ ^! gases to ! coal-gas2 by mix+ c>buret$ wat]-gas ) coal-gas2 by c>buret+ inf]ior coal-gases2 & by mix+ oil-gas ) inf]ior coal-gas4 ,wat]-gas is ( l[ illum9at+ value1 b aft] x is c>buret$ x burns ) a brilliant flame4 ,! wat]-gas is made by rais+ ! temp]ature ( ! fuel b$ ( h>d coal or coke by =c$ air1 :i* is !n cut (f1 :ile /eam is pass$ ?r\gh ! inc&esc5t fuel4 ,?is yields hydrog5 & c>bon monoxide4 ,to make c>buret$ wat]-gas1 oil-gas is mix$ ) x1 ! latt] be+ made by heat+ oil 9 retorts4 ,a great _m k9ds ( gas are made :i* are det]m9$ by ! requirem5ts & ! raw mat]ials available4 ,! am\nt ( illum9at+ gas yield$ by a ton ( fuel1 ( c\rse1 v>ies ) ! me?od ( manufacture1 ) ! raw mat]ial1 & ) ! use to :i* ! fuel is to be put4 ,! production ( coal-gas p] ton ( coal is ( ! ord] ( magnitude ( #aj1jjj cubic feet4 ,a typical yield by weight ( a coal-gas retort is1 #aj1jjj cubic feet ( gas #ag p] c5t4 coke #gj t> #e ammoniacal liquid #h ,! coke is n pure c>bon b conta9s ! non-volatile m9]als :i* w rema9 z a% :5 ! coke is burn$1 j z if ! orig9al coal _h be5 burn$4 ,on ! cr[n ( ! retort us$ 9 coal-gas production1 pure c>bon is deposit$4 ,?is is us$ = electric-arc c>bons & = o!r purposes4 ,f ! t> _m products are d]iv$ su* z anil9e dyes1 b5z5e1 c>bolic acid1 picric acid1 nap?al5e1 pit*1 an?rac5e1 & sac*>94 ,a typical analysis ( ! gas di/ill$ f coal is v approximately z foll[s1 ,hydroc>bons #dj p] c5t4 ,hydrog5 #ej ,c>bon monoxide #d ,nitrog5 #d ,c>bon dioxide #a ,v>i\s o!r gases #a ,x is se5 t illum9at+ gas is n a def9ite comp\nd b a mixture ( a numb] ( gases4 ,! proportion ( ^! is controll$ 9 s f> z possible 9 ord] to obta9 illum9at+ value & "s ( !m are r$uc$ to v small p]c5tages because !y are valueless z illum9ants or ev5 h>mful4 ,! con/itu5ts are se5 to consi/ ( light-giv+ hydroc>bons1 ( gases :i* yield *iefly heat1 & ( impurities4 ,! *ief hydroc>bons f\nd 9 illum9at+ gas are1 e?yl5e ,c#b;,h#d crotonyl5e ,c#d;,h#f propyl5e ,c#c;,h#f b5z5e ,c#f;,h#f butyl5e ,c#d;,h#h tolu5e ,c#g;,h#h amyl5e ,c#e;,h#aj xyl5e ,c#h;,h#aj acetyl5e ,c#b;,h#b me?ane ,c ,h#d allyl5e ,c#c;,h#d e?ane ,c#b;,h#f ,a gas :i* has play$ a prom95t "p 9 light+ is acetyl5e1 produc$ by ! int]action ( wat] & calcium c>bide4 ,no o!r gas easily produc$ ^u a comm]cial scale yields z mu* light1 volume = volume1 z acetyl5e4 ,x has ! great advantage ( be+ easily prep>$ f raw mat]ial ^: yield ( gas is consid]ably great] = a giv5 am\nt ?an ! raw mat]ials :i* are us$ 9 mak+ o!r illum9at+ gases4 ,! simplicity ( ! manufacture ( acetyl5e f calcium c>bide & wat] gives to ?is gas a great advantage 9 "s cases4 ,x has s]v$ = individual light+ 9 h\ses & 9 o!r places :]e gas or electric s]vice 0 unavailable4 ,:]e space is limit$ x also _h an advantage & 0 adopt$ to "s ext5t on automobiles1 motor-boats1 %ips1 ligh?\ses1 & railway c>s be=e electric light+ 0 develop$ = ^! purposes4 ,! color ( ! acetyl5e flame is satisfactory & x is extremely brilliant comp>$ ) mo/ flames4 ,an int]e/+ exp]im5t is f\nd 9 plac+ a sp>k-gap 9 ! flame & s5d+ a s]ies ( sp>ks across x4 ,if ! conditions are prop] ! flame w became v mu* bright]4 ,:5 ! gas issues f a prop] jet "u suffici5t pressure1 ! flame is q /eady4 ,its lum9\s effici5cy gives x an advantage ov] o!r op5 gas-flames 9 light+ rooms1 because = ! same am\nt ( light x vitiates ! air & exhau/s ! oxyg5 to a less degree ?an ! o!rs4 ,( c\rse1 9 ^! respects ! gas-mantle is sup]ior4 ,! reaction :i* takes place :5 wat] & calcium c>bide are br\ght toge!r is a d\ble decomposition & is repres5t$ by1 ,ca,c#b ,h#b,o ,c#b;,h#b ,ca,o ,x w be se5 t ! products are acetyl5e gas & calcium oxide or lime4 ,! lime1 be+ hydroscopic & be+ 9 ! pres5ce ( wat] or wat]-vapor 9 ! acetyl5e g5]ator1 really becomes calcium hydroxide ,ca7,,oh7#b1 commonly call$ slak$ lime4 ,if !re are impurities 9 ! calcium c>bide1 x is sometimes necess>y to purify ! gas be=e x may be safely us$ = int]ior light+4 ,! burn]s & mantles us$ 9 acetyl5e light+ are ess5tially ! same z ^? = o!r gas-light+1 except+1 ( c\rse1 t !y are especially adapt$ = x 9 m9or details4 ,! *ief s\rce ( calcium c>bide 9 ?is c\ntry is ! electric furnace4 ,*eap electrical en]gy f hydro-electric developm5ts1 su* z ! ,niag>a plants1 h done mu* to make ! e>? yield its elem5ts4 ,alum9um is v preval5t 9 ! soil ( ! e>?'s surface1 because its oxide1 alum9a1 is a *ief con/itu5t ( ord9>y clay4 ,b ! elem5ts1 alum9um & oxyg51 cl+ t5aci\sly to ea* o!r & only ! electric furnace ) its excessively high temp]atures has be5 able to sep>ate !m on a l>ge comm]cial scale4 ,simil>ly1 calcium is f\nd 9 v>i\s comp\nds ov] ! e>?'s surface4 ,lime/one ab\nds widely1 h5ce ! oxide & c>bonate ( lime are wide-spread4 ,b calcium cl+s tightly to ! o!r elem5ts ( its comp\nds & x has tak5 ! electric furnace to br+ x to submission4 ,! *eapness ( calcium c>bide is due to ! developm5t ( *eap electric p[]4 ,x is said t calcium c>bide 0 discov]$ z a by-product ( ! electric furnace by accid5tally ?r[+ wat] ^u ! wa/e mat]ials ( a furnace process4 ,! discov]y ( a comm]cial scale ( manufacture ( calcium c>bide has be5 a boon to isolat$ light+4 ,electric light+ has usurp$ its place on ! automobile & is mak+ inroads 9 c\ntry-home light+4 ,d\btless1 acetyl5e w cont9ue to s]ve = _m ye>s1 b its future does n appe> z bright z x did _m ye>s ago4 ,! ,p9ts* gas1 us$ to "s ext5t 9 railroad pass5g]-c>s 9 ?is c\ntry1 is an oil-gas produc$ by ! de/ructive di/illation ( petroleum or o!r m9]al oil 9 retorts heat$ ext]nally4 ,! product consi/s *iefly ( me?ane & heavy hydroc>bons ) a small am\nt ( hydrog54 ,9 ! e>ly days ( railways1 "s tra9s 7 n run aft] d>k & ^? :i* 7 op]at$ 7 n always light$4 ,at fir/ attempts 7 made at light+ railway c>s ) compress$ coal-gas1 b ! disadvantage ( ?is 0 ! l>ge tank requir$4 ,obvi\sly1 a gas ( high] illum9at+-value p] volume 0 desir$ :]e limit$ /orage space 0 available1 & ,p9ts* turn$ 8 att5tion to oil-gas4 ,gas suff]s 9 illum9at+-value ^u be+ compress$1 b oil-gas suff]s only ab\t half ! loss t coal-gas does4 ,9 ab\t #ahhj ,p9ts* develop$ a me?od ( weld+ cyl9d]s & buoys :i* satisfi$ ligh?\se au?orities & he 0 enabl$ to furni% ^! fill$ ) compress$ gas4 ,?us ! buoy 0 its own gas-tank4 ,he devis$ lant]ns :i* w\ld rema9 light$ reg>dless ( w9d & waves & ?us ga9$ a />t ) 8 compress$-gas sy/ems4 ,he compress$ ! gas to a pressure ( ab\t "o hundr$ & fifty p\nds p] squ>e in* & 0 oblig$ to devise a r$uc] :i* w\ld deliv] ! gas to ! burn] at ab\t "o p\nd p] squ>e in*4 ,?is regulator s]v$ well ?r\gh\t _m ye>s ( exact+ s]vice4 ,! sy/em began to be adopt$ on %ips & railroads 9 #ahhj & = _m ye>s x has s]v$ well4 ,al?\gh gas-light+ has affect$ ! activities ( mank9d consid]ably by int5sify+ comm]ce & indu/ry & by advanc+ social progress1 ! illum9ants :i* ev5tually took ! lead h ext5d$ ! possibilities & influ5ces ( artificial light4 ,9 ! brief span ( a c5tury civiliz$ man is almo/ totally indep5d5t ( natural light 9 ^? fields ov] :i* he has control4 ,:at ano!r c5tury w br+ c be pr$ict$ only f ! accompli%m5ts ( ! pa/4 ,^! indicate possibilities beyond ! p[]s ( imag9ation4 ,,ix ,,! ,,electric ,,arcs ,e>ly 9 #ahjj ,volta wrote a lett] to ! ,presid5t ( ! ,royal ,society ( ,london ann\nc+ ! epo*al discov]y ( a device n[ kn[n z ! voltaic pile4 ,?is lett] 0 publi%$ 9 ! ,transactions & x creat$ great excitem5t among sci5tific m51 :o imm$iately began active inve/igations ( c]ta9 electrical ph5om5a4 ,volta %[$ t all metals c\ld be arrang$ 9 a s]ies s t ea* "o w\ld indicate a positive electric pot5tial :5 9 contact ) any metal foll[+ x 9 ! s]ies4 ,he con/ruct$ a pile ( metal disks consi/+ ( z9c & copp] alt]nat$ & sep>at$ by wet clo?s4 ,at fir/ he believ$ t m]e contact 0 suffici5t1 b :51 lat]1 x 0 %[n t *emical action took place1 rapid progress 0 made 9 ! con/ruction ( voltaic cells4 ,! next /ep aft] 8 pile 0 con/ruct$ 0 to place pairs ( /rips ( copp] & z9c 9 cups conta9+ wat] or dilute acid4 ,volta receiv$ _m honors = 8 discov]y1 :i* contribut$ s mu* to ! developm5t ( electrical sci5ce & art--among !m a call to ,p>is by ,bonap>te to exhibit 8 electrical exp]im5ts1 & to receive a m$al /ruck 9 8 honor4 ,:ile ,volta 0 be+ %[]$ ) honors1 v>i\s sci5tific m5 ) great en?usiasm 7 ent]+ new fields ( rese>*1 among :i* 0 ! heat+ value ( electric curr5t & p>ticul>ly ( electric sp>ks made by break+ a circuit4 ,late 9 #ahjj ,sir ,humphrey ,davy 0 ! fir/ to use *>coal = ! sp>k+ po9ts4 ,9 a lecture be=e ! ,royal ,society 9 ! foll[+ ye> he describ$ & demon/rat$ t ! sp>k pass+ betwe5 two pieces ( *>coal 0 l>g] & m brilliant ?an betwe5 brass sph]es4 ,app>5tly1 he 0 produc+ a feeble arc1 r ?an a pure sp>k4 ,9 ! ye>s :i* imm$iately foll[$ _m sci5tific m5 9 ,engl&1 ,france1 & ,g]many 7 publi%+ ! results ( _! /udies ( electrical ph5om5a bord]+ ^u ! arc4 ,by subscription among ! memb]s ( ! ,royal ,society1 a voltaic batt]y ( two ?\s& cells 0 obta9$ & 9 #ahjh ,davy exhibit$ ! electric arc on a l>ge scale4 ,x is difficult to judge f ! reports ( ^! e>ly inve/igations :o 0 ! fir/ to recognize ! diff]5ce betwe5 ! sp>k & ! arc4 ,c]ta9ly ! descriptions indicate t ! simple sp>k 0 n be+ exp]im5t$ )1 b ! s\rce ( electric curr5t available at t "t 0 ( su* high resi/ance t only feeble arcs c\ld h be5 produc$4 ,9 #ahji ,davy demon/rat$ publicly an arc obta9$ by a curr5t f a ,volta pile ( "o ?\s& plates4 ,?is he describ$ z a mo/ brilliant flame1 ( f half an in* to "o & a qu>t] in*es 9 l5g?4 ,9 ! libr>y ( ! ,royal ,society1 ,davy's notes made dur+ ! ye>s ( #ahje & #ahab are available 9 two l>ge volumes4 ,^! 7 arrang$ & pag$ by ,f>aday1 :o 0 de/9$ to contribute greatly to ! future developm5t ( ! sci5ce & art ( electricity4 ,9 "o ( ^! volumes is f\nd an acc\nt ( a lecture-exp]im5t by ,davy :i* c]ta9ly is a description ( ! electric arc4 ,an extract ( ?is acc\nt is z foll[s3 ,! sp>k presumably ! arc1 ! light ( :i* 0 s int5se z to resemble t ( ! sun1 444 produc$ a dis*>ge ?r\gh heat$ air ne>ly ?ree in*es 9 l5g?1 & ( a dazzl+ spl5dor4 ,sev]al bodies :i* _h n be5 fus$ be=e 7 fus$ by ?is flame4444 ,*>coal 0 made to evaporate1 & plumbago appe>$ to fuse 9 vacuo4 ,*>coal 0 ignit$ to int5se :it5ess by x 9 oxymuriatic acid1 & volatiliz$ by x1 b )\t be+ decompos$4 ,f a consid]ation ( 8 s\rce ( electricity1 a voltaic pile ( two ?\s& plates1 x is c]ta9 t ?is c\ld n h be5 an electric sp>k4 ,lat] 9 8 notes ,davy cont9u$3 444! *>coal became ignit$ to :itness1 & by )draw+ ! po9ts f ea* o!r1 a con/ant dis*>ge took place ?r\gh ! heat$ air1 9 a space at lea/ equal to f\r in*es1 produc+ a mo/ brilliant asc5d+ ar* ( light1 broad & conical 9 =m 9 ! middle4 ,?is is surely a description ( ! electric arc4 ,app>5tly ! electrodes 7 9 a horizontal position & ! arc !re=e 0 horizontal4 ,ow+ to ! rise ( ! heat$ air1 ! arc t5d$ to rise 9 ! =m ( an ar*4 ,f ?is appe>ance ! t]m arc evolv$ & ,davy himself 9 #ahbj def9itely nam$ ! electric flame1 ! arc4 ,?is "n 0 cont9u$ 9 use ev5 aft] ! two c>bons 7 arrang$ 9 a v]tical co-axial position & ! arc no m ar*$4 ,an int]e/+ sci5tific ev5t ( #ahbj 0 ! discov]y by ,arago & by ,davy indep5d5tly t ! arc c\ld be deflect$ by a magnet & t x 0 simil> to a wire c>ry+ curr5t 9 t !re 0 a magnetic field ar\nd x4 ,?is has be5 tak5 advantage ( 9 c]ta9 mod]n arc-lamps 9 :i* incl9$ c>bons are us$4 ,9 ^! arcs a magnet keeps ! arc 9 place1 = )\t ! magnet ! arc w\ld t5d to climb up ! c>bons & g out4 ,9 #ahch ,gassiot made ! discov]y t ! temp]ature ( ! positive electrode ( an electric arc is mu* great] ?an t ( ! negative electrode4 ,?is is expla9$ 9 electronic !ory by ! bomb>dm5t ( ! positive electrode by negative electrons or corpuscles ( electricity4 ,?is temp]ature-diff]5ce 0 lat] tak5 into acc\nt 9 design+ direct-curr5t arc-lamps1 = inasmu* z mo/ ( ! light f an ord9>y arc is emitt$ by ! end ( ! positive electrode1 ?is 0 plac$ above ! negative electrode4 ,9 ?is mann] mo/ ( ! light f ! arc is direct$ d[nw>d :]e desir$4 ,9 ! few in/ances 9 mod]n times :]e ! ord9>y direct-curr5t arc has be5 us$ = indirect light+1 9 :i* case ! arc is above an inv]t$ %ade1 ! positive c>bon is plac$ bel[ ! negative "o4 ,gassiot fir/ prov$ t ! positive electrode is hott] ?an ! negative "o by /rik+ an arc betwe5 ! ends ( two horizontal wires ( ! same sub/ance & diamet]4 ,aft] ! arc op]at$ = "s "t1 ! positive wire 0 melt$ = su* a di/ance t x b5t d[nw>d1 b ! negative rema9$ q /raight4 ,*>coal 0 us$ = ! electrodes 9 all ! e>ly exp]im5ts1 b ow+ to ! int5se heat ( ! arc1 x burn$ away rapidly4 ,a progressive /ep 0 made 9 #ahdc :5 electrodes 7 fir/ made by ,f\cault f ! c>bon deposit$ 9 retorts 9 :i* coal 0 di/ill$ 9 ! production ( coal-gas4 ,h[ev]1 *>coal1 ow+ to its s(t por\s "*1 gives a long] arc & a l>g] flame4 ,9 #ahgg ! cor$ c>bons 7 introduc$4 ,^! consi/ ( h>d mold$ c>bon rods 9 :i* !re is a core ( s(t c>bon4 ,9 ^! are comb9$ ! advantages ( *>coal & h>d c>bon & ! core 9 burn+ away m rapidly has a t5d5cy to hold ! arc 9 ! c5t]4 ,mod]n c>bons = ord9>y arc-lamps are g5]ally made ( a mixture ( retort-c>bon1 soot1 & coal-t>4 ,?is pa/e is =c$ ?r\gh dies & ! c>bons are bak$ at a fairly high temp]ature4 ,a v>iation 9 ! h>dness ( ! c>bons may be obta9$ z ! requirem5ts dem& by v>y+ ! proportions ( soot & retort-c>bon4 ,cor$ c>bons are made by ins]t+ a small rod 9 ! c5t] ( ! die & ! c>bons are =m$ ) a holl[ core4 ,?is may be fill$ ) a s(t] c>bon4 ,if two c>bons connect$ to a s\rce ( electric curr5t are br\ght toge!r1 ! circuit is complet$ & a curr5t fl[s4 ,if ! two c>bons are n[ slightly sep>at$1 an arc w be =m$4 ,z ! arc burns ! c>bons wa/e away & 9 ! case ( direct curr5t1 ! positive decreases 9 l5g? m rapidly ?an ! negative "o4 ,?is is due l>gely to ! extremely high temp]ature ( ! positive tip1 :]e ! c>bon fairly boils4 ,a crat] is =m$ at ! positive tip & ?is is always *>act]i/ic ( ! positive c>bon ( ! ord9>y arc1 al?\gh x becomes m %all[ z ! arc-l5g? is increas$4 ,! negative tip has a bright spot to :i* "o end ( ! arc is atta*$4 ,by wa/+ away1 ! l5g? ( ! arc increases & likewise its resi/ance1 until f9ally insuffici5t curr5t w pass to ma9ta9 ! arc4 ,x !n goes out & to />t x ! c>bons mu/ be br\ght toge!r & sep>at$4 ,! me*anisms ( mod]n arc-lamps p]=m ^! functions automatically by ! +5i\s use ( electromagnets4 ,! int]ior ( ! arc is ( a violet color & ! ext]ior is a gre5i% yell[4 ,! :ite-hot spot on ! negative tip is g5]ally surr\nd$ by a fr+e ( agitat$ globules :i* consi/ ( t> & o!r +r$i5ts ( c>bons4 ,(t5 mat]ial is deposit$ f ! positive crat] ^u ! negative tip & ^! accretions may build up a r\nd$ tip4 ,?is deposit sometimes int]f]es ) ! prop] =mation ( ! arc & also ) ! light f ! arc4 ,x is (t5 responsible = ! hiss+ noise1 al?\gh ?is hiss+ occurs ) any l5g? ( arc :5 ! curr5t is suffici5tly increas$4 ,! hiss+ seems to be due to ! crat] enl>g+ "u excessive curr5t until x passes ! conf9es ( ! cross-section ( ! c>bon4 ,x ?us t5ds to run up ! side1 :]e x comes 9 contact ) oxyg5 ( ! air4 ,9 ?is mann] ! c>bon is directly burn$ in/ead ( be+ vaporiz$1 z x is :5 ! hot crat] is small & is protect$ f ! air by ! arc itself4 ,! temp]ature ( ! positive crat] is 9 ! neighborhood ( #fjjj to #gjjj;,f4 ,! brightness ( ! arc "u pressure is ! greate/ produc$ by artificial means & is v int5se4 ,by putt+ ! arc "u high pressure1 ! brightness ( ! sun may be atta9$4 ,! temp]ature ( ! hotte/ spot on ! negative tip is ab\t a ?\s& degrees bel[ t ( ! positive4 ,no great dem& arose = arc-lamps until ! developm5t ( ! ,gramme dynamo 9 #ahgj1 :i* provid$ a practicable s\rce ( electric curr5t4 ,9 #ahgf ,jablo*kov inv5t$ 8 fam\s electric c&le consi/+ ( two rods ( c>bon plac$ side by side b sep>at$ by insulat+ mat]ial4 ,9 ?is c\ntry ,bru% 0 ! pione] 9 ! developm5t ( op5 arc-lamps4 ,9 #ahgg he inv5t$ an arc-lamp & an effici5t =m ( dynamo to supply ! electrical en]gy4 ,! fir/ arc-lamps 7 ord9>y direct-curr5t op5 arcs & ! c>bons 7 made f high-grade coke1 lampblack1 & syrup4 ,! upp] positive c>bon 9 ^! lamps is consum$ at a rate ( "o to two in*es p] h\r4 ,inasmu* z ab\t #he p] c5t4 ( ! total light is emitt$ by ! upp] 7positive7 c>bon & mo/ ( ?is f ! crat]1 ! l[] c>bon is made z small z possible 9 ord] n to ob/ruct any m light ?an necess>y4 ,! positive c>bon ( ! op5 arc is (t5 cor$ & ! negative is a small] "o ( solid c>bon4 ,?is comb9ation op]ates q satisfactorily1 b sometimes solid c>bons are us$ outdoors4 ,! voltage across ! arc is ab\t #ej volts4 ,9 #ahdf ,/aite discov]$ t ! c>bons ( an arc enclos$ 9 a glass vessel into :i* ! air 0 n freely admitt$ 7 consum$ less rapidly ?an :5 ! arc op]at$ 9 ! op5 air4 ,aft] ! appe>ance ( ! dynamo1 :5 increas$ att5tion 0 giv5 to ! developm5t ( arc-lamps1 ?is pr9ciple ( enclos+ ! arcs 0 aga9 consid]$4 ,! e>ly attempts 9 ab\t #ahhj 7 unsuccessful because l[ voltages 7 us$ & x 0 n until ! discov]y 0 made t ! negative tip builds up consid]ably = voltages "u #fe volts1 t high] voltages 7 employ$4 ,9 #ahic m>k$ improvem5ts 7 consummat$ & ,j&us br\ght out a successful enclos$ arc op]at+ at #hj volts4 ,m>ks contribut$ l>gely to ! success ( ! enclos$ arc by %[+ t a small curr5t & a high voltage ( #hj to #he volts 7 ! requisites = a satisfactory enclos$ arc4 ,! pr9ciple ( ! enclos$ arc is simple4 ,a closely fitt+ glass globe surr\nds ! arc1 ! fit be+ z close z ! fe$+ ( ! c>bons w p]mit4 ,:5 ! arc is /ruck ! oxyg5 is rapidly consum$ & ! heat$ gases & ! enclosure *eck ! supply ( fre% air4 ,! result is t ! c>bons are consum$ ab\t "o t5? z rapidly z 9 ! op5 arc4 ,!re is no crat] =m$ on ! positive tip & ! arc w&]s consid]ably4 ,! effici5cy ( ! enclos$ arc z a light-produc] is l[] ?an t ( ! op5 arc1 b x f\nd favor because ( its sl[ rate ( consumption ( ! c>bons & consequ5t decreas$ att5tion necess>y4 ,?is arc op]ates a hundr$ h\rs or m )\t trimm+1 & w !re=e op]ate a week or m 9 /reet-light+ )\t att5tion4 ,:5 x is consid]$ t op5 arcs = all-night burn+ 7 suppli$ ) two pairs ( c>bons1 ! second set go+ into use automatically :5 ! fir/ 7 consum$1 ! value ( ! enclos$ arc is app>5t4 ,h[ev]1 ! op5 arc has s]v$ well & has giv5 way to great] improvem5ts4 ,x is rapidly disappe>+ f use4 ,! alt]nat+-curr5t arc-lamp 0 develop$ aft] ! appe>ance ( ! direct-curr5t op5-arc & has be5 widely us$4 ,x has no positive or negative c>bons1 = ! alt]nat+ curr5t is rev]s+ 9 direction usually at ! rate ( #abj times p] second2 t is1 x passes ?r\gh #fj complete cycles dur+ ea* second4 ,no m>k$ crat]s =m on ! tips & ! two c>bons are consum$ at ab\t ! same rate4 ,! av]age temp]ature ( ! c>bon tips is l[] ?an t ( ! positive tip ( a direct-curr5t arc1 ) ! result t ! lum9\s effici5cy is l[]4 ,^! arcs h be5 made ( bo? ! op5 & enclos$ type4 ,!y are *>act]iz$ by a humm+ noise due to ! effect ( alt]nat+ curr5t ^u ! me*anism & also ^u ! air ne> ! arc4 ,?is humm+ s\nd is q diff]5t f ! occasional hiss+ ( a direct-curr5t arc4 ,:5 s(t c>bons are us$1 ! arc is l>g] & app>5tly ?is mass ( vapor r$uces ! humm+ consid]ably4 ,! humm+ is n v app>5t = ! enclos$ alt]nat+-curr5t arc4 ,! alt]nat+ arc c easily be detect$ by closely obs]v+ mov+ objects4 ,if a p5cil or co9 be mov$ rapidly1 a numb] ( images appe> :i* are due to ! pulsat+ "* ( ! light4 ,at ea* rev]sal ( ! curr5t1 ! curr5t rea*es z]o value & ! arc is virtually ext+ui%$4 ,!re=e1 !re is a maximum brightness midway betwe5 ! rev]sals4 ,v>i\s types ( all ^! arcs h be5 develop$ to meet ! diff]5t requirem5ts ( ord9>y light+ & to adapt ?is me?od ( light-production to ! ne$s ( projection1 /age-equipm5t1 ligh?\ses1 se>*-lights1 & o!r applications4 ,up to ?is po9t ! ord9>y c>bon arc has be5 consid]$ & x has be5 se5 t mo/ ( ! light is emitt$ by ! gl[+ end ( ! positive c>bon4 ,9 fact1 ! light f ! arc itself is negligible4 ,a logical /ep 9 ! developm5t ( ! arc-lamp 0 to introduce salts 9 ord] to obta9 a lum9\s flame4 ,?is possibility z appli$ to ord9>y gas-flames _h be5 kn[n = ye>s & x is surpris+ t x _h n be5 e>ly appli$ to c>bons4 ,app>5tly ,brem] 9 #ahih 0 ! fir/ to introduce fluorides ( calcium1 b>ium1 & /rontium4 ,! salts deflagrate & a lum9\s flame envelops ! ord9>y feeble arc-flame4 ,f ^! arcs mo/ ( ! light is emitt$ by ! arc itself1 h5ce ! "n flame-arcs4 ,by ! introduction ( metallic salts into ! c>bons ! possibilities ( ! arc-lamp 7 greatly ext5d$4 ,! lum9\s output ( su* lamps is mu* great] ?an t ( an ord9>y c>bon arc us+ ! same am\nt ( electrical en]gy4 ,fur!rmore1 ! color or spectral "* ( ! light may be v>i$ ?r\gh a wide range by ! use ( v>i\s salts4 ,= example1 if c>bons are impregnat$ ) calcium fluoride1 ! arc-flame :5 exam9$ by means ( a spectroscope w be se5 to conta9 ! *>act]i/ic spectrum ( calcium1 namely1 "s gre51 orange1 & r$ rays4 ,^! comb9e to give to ?is arc a v yell[ color4 ,z expla9$ 9 a previ\s *apt]1 ! salts = ?is purpose may be wisely *os5 f a k ( _! fundam5tal or *>act]i/ic flame-spectra4 ,^! lamps h be5 develop$ to meet a v>iety ( ne$s & _! lum9\s effici5cies range f #bj to #dj lum5s p] watt1 be+ sev]al times t ( ! ord9>y c>bon op5-arc4 ,! r$ flame-arc owes its color *iefly to /rontium1 ^: *>act]i/ic visible spectrum consi/s *iefly ( r$ & yell[ rays4 ,b>ium gives to ! arc a fairly :ite color4 ,! yell[ & s-call$ :ite flame-arcs h be5 mo/ commonly us$4 ,flame-arcs h be5 produc$ :i* are close to daylight 9 color1 & p[]ful blue-:ite flame-arcs h satisfi$ ! ne$s ( v>i\s *emical indu/ries & photographic processes4 ,^! arcs are g5]ally op]at$ 9 a space :]e ! air-supply is re/rict$ simil> to ! enclos$-arc pr9ciple4 ,inasmu* z poison\s fumes are emitt$ 9 l>ge quantities f "s flame-arcs1 !y are n us$ indoors )\t r g5]\s v5tilation4 ,9 fact1 ! flame-arcs are su* p[]ful light-s\rces t !y are almo/ entirely us$ outdoors or 9 v l>ge int]iors especially ( ! type ( op5 factory build+s4 ,!y are made = bo? direct & alt]nat+ curr5t & ! me*anisms h be5 ( sev]al types4 ,! electrodes are consum$ r rapidly s !y are made z long z possible4 ,9 "o type ( arc1 ! c>bons are bo? f$ d[nw>d1 _! l[] ends =m+ a n>r[ ,v ) ! arc-flame betwe5 _! tips4 ,"u ^! conditions ! arc t5ds to travel v]tically & f9ally to /ret* itself to ext9ction4 ,h[ev]1 ! arc is kept 9 place by means ( a magnet above x :i* repels ! arc & holds x at ! ends ( ! c>bons4 ,! *ief objection to ! e>ly flame-arcs 0 ! necessity = frequ5t r5ewal ( ! c>bons4 ,?is 0 ov]come to a l>ge ext5t 9 ! ,j&us reg5]ative lamp 9 :i* ! arc op]ates 9 a glass enclosure surr\nd$ by an opal globe4 ,h[ev]1 9 addition to ! inn] glass enclosure1 two cool+ *amb]s ( metal are atta*$ to x4 ,air ent]s at ! bottom & ! fumes f ! arc pass upw>d & into ! cool+ *amb]s1 :]e ! solid products are deposit$4 ,! air on return+ to ! bottom is ?us reliev$ ( ^! solids & ! inn] glass enclosure rema9s fairly clean4 ,! l[] c>bon is impregnat$ ) salts = produc+ ! lum9\s flame & ! upp] c>bon is cor$4 ,! life ( ! electrodes is ab\t sev5ty-five h\rs4 ,! next /ep 0 ! introduction ( ! s-call$ lum9\s-arc :i* is a flame-arc ) entirely diff]5t electrodes4 ,! l[] 7negative7 electrode consi/s ( an iron tube pack$ *iefly ) magnetite 7an iron oxide7 & titanium oxide 9 ! approximate proportions ( ?ree to "o respectively4 ,! magnetite is a conductor ( electricity :i* is easily vaporiz$4 ,! arc-flame is l>ge & ! titanium gives x a high brilliancy4 ,! positive electrode1 usually ! upp] "o1 is a %ort1 ?ick1 solid cyl9d] ( copp]1 :i* is consum$ v sl[ly4 ,?is lamp1 kn[n z ! magnetite-arc1 has a lum9\s effici5cy ( ab\t #bj lum5s p] watt ) a cle> glass globe4 ,! me*anisms :i* /rike ! arc & fe$ ! c>bons are +5i\s devices ( _m designs dep5d+ ^u ! k9d ( arc & ^u ! "* ( ! electric circuit to :i* x is connect$4 ,late developm5ts 9 electric inc&esc5t filam5t lamps h usurp$ "s ( ! fields 9 :i* ! arc-lamp reign$ supreme = ye>s & its future does n appe> z bright n[ z x did t5 ye>s ago4 ,high-int5sity arcs h be5 devis$ ) small c>bons = special purposes & consid]$ z a :ole a great am\nt ( +5uity has be5 exp5d$ 9 ! developm5t ( arc-lamps4 ,!re w be a cont9u$ dem& = arc-lamps1 = sci5tific developm5ts are op5+ new fields = !m4 ,_! value 9 photo-engrav+1 9 ! mov+-picture production /udios1 9 mov+-picture projection1 & 9 c]ta9 aspects ( /age-light+ is firmly e/abli%$1 & x appe>s t !y w f9d application 9 c]ta9 *emical indu/ries because ! arc is a p[]ful s\rce ( radiant en]gy :i* is v active 9 its effects ^u *emical reactions4 ,! lum9\s effici5cies ( arc-lamps dep5d ^u s _m conditions t x is difficult to pres5t a concise comp>ison2 h[ev]1 ! foll[+ may suffice to %[ ! ranges ( lum9\s output p] watt "u actual conditions ( usage4 ,^! effici5cies1 ( c\rse1 are less ?an ! effici5cies ( ! arc alone1 because ! losses 9 ! me*anism1 globes1 etc41 are includ$4 ,lum5s p] watt ,op5 c>bon arc #d to #h ,enclos$ c>bon arc #c to #g ,enclos$ flame-arc 7yell[ or :ite7 #ae to #be ,lum9\s arc #aj to #be ,ano!r lamp diff]+ widely 9 appe>ance f ! prec$+ arcs may be describ$ "h because x is kn[n z ! m]cury-arc4 ,9 ?is lamp m]cury is conf9$ 9 a transp>5t tube & an arc is />t$ by mak+ & break+ a m]cury connection betwe5 ! two electrodes4 ,! arc may be ma9ta9$ ( a l5g? ( sev]al feet4 ,p]haps ! fir/ m]cury-arc 0 produc$ 9 #ahfj by ,way1 :o p]mitt$ a f9e jet ( m]cury to fall f a res]voir into a vessel1 ! res]voir & receiv] be+ connect$ to ! poles ( a batt]y4 ,! electric curr5t scatt]$ ! jet & betwe5 ! drops arcs 7 =m$4 ,he exhibit$ ?is novel light-s\rce on ! ma/ ( a ya*t & x receiv$ great att5tion4 ,lat]1 v>i\s inve/igators exp]im5t$ on ! production ( a m]cury-arc & ! fir/ successful ones 7 made 9 ! =m ( an inv]t$ ,u-tube ) ! ends fill$ ) m]cury & ! rema9d] ( ! tube exhau/$4 ,coop] ,hewitt 0 a successful pione] 9 ! production ( practicable m]cury-arcs4 ,he made !m *iefly 9 ! =m ( /raight tubes ( glass up to sev]al feet 9 l5g?1 ) enl>g$ ends to facilitate cool+4 ,! tubes are incl9$ s t ! m]cury vapor :i* cond5ses w run back into ! enl>g$ end1 :]e a pool ( m]cury =ms ! negative electrode4 ,! arc may be />t$ by tilt+ ! tube s t a m]cury ?read runs d[n ! side & connects ) ! positive electrode ( iron4 ,! heat ( ! arc volatilizes ! m]cury s t an arc ( consid]able l5g? is ma9ta9$4 ,! tilt+ is done by electromagnets4 ,/>t+ has also be5 accompli%$ by means ( a heat+ coil & also by an electric sp>k4 ,! lamps are /abiliz$ by resi/ance & inductance coils4 ,"o ( ! defects ( ! light emitt$ by ! inc&esc5t vapor ( m]cury is its paucity ( spectral colors4 ,its visible spectrum consi/s *iefly ( violet1 blue1 gre51 & yell[ rays4 ,x emits virtually no r$ rays1 &1 !re=e1 r$ objects appe> devoid ( r$4 ,! human face appe>s gha/ly "u ?is light & x di/orts colors 9 g5]al4 ,h[ev]1 x possesses ! advantages ( high effici5cy1 ( reasonably l[ brightness1 ( high act9ic value1 & ( reveal+ detail cle>ly4 ,v>i\s attempts h be5 made to improve ! color ( ! light by add+ r$ rays4 ,reflectors ( a fluoresc5t r$ dye h be5 us$ ) "s success1 b su* a me?od r$uces ! lum9\s effici5cy ( ! lamp consid]ably4 ,! dye fluoresces r$ "u ! illum9ation ( ultra-violet1 violet1 & blue rays2 t is1 x has ! prop]ty ( conv]t+ radiation ( ^! wave-l5g?s into radiant en]gy ( long] wave-l5g?s4 ,by ! use ( electric inc&esc5t filam5t lamps 9 conjunction ) m]cury-arcs1 a fairly satisfactory light is obta9$4 ,_m exp]im5ts h be5 made by add+ o!r sub/ances to ! m]cury1 su* z z9c1 ) ! hope t ! spectrum ( ! o!r sub/ance w\ld comp5sate ! defects 9 ! m]cury spectrum4 ,h[ev] no success has be5 rea*$ 9 ?is direction4 ,by ! use ( a qu>tz tube :i* c )/& a mu* high] temp]ature ?an glass1 ! curr5t d5sity c be greatly increas$4 ,?us a small qu>tz tube ( inc&esc5t m]cury vapor w emit z mu* light z a long glass tube4 ,! qu>tz m]cury-arc produces a light :i* is almo/ :ite1 b ! actual spectrum is v diff]5t f t ( :ite sunlight4 ,al?\gh "s r$ rays are emitt$ by ! qu>tz arc1 its spectrum is ess5tially ! same z t ( ! glass-tube arc4 ,qu>tz transmits ultra-violet radiation1 :i* is h>mful to ! eyes1 & inasmu* z ! m]cury vapor emits su* rays1 a glass globe %\ld be us$ to enclose ! qu>tz tube :5 ! lamp is us$ = ord9>y light+ purposes4 ,x is =tunate t su* radically diff]5t k9ds ( light-s\rces are available1 = 9 ! complex activities ( ! pres5t "t all are 9 dem&4 ,! qu>tz m]cury-arc f9ds _m isolat$ uses1 ow+ to its weal? ( ultra-violet radiation4 ,x is valuable z a s\rce ( ultra-violet = excit+ phosphoresc5ce1 = exam9+ ! transmission ( glasses = ?is radiation1 = /]iliz+ wat]1 = m$ical purposes1 & = photography4 ,x ,,! ,,electric ,,inc&esc5t ,,filam5t ,,lamps ,prior to #ahjj electricity 0 *iefly a play?+ = m5 ( sci5tific t5d5cies & x 0 n until ,volta inv5t$ ! electric pile or batt]y t c]ta9 sci5tific m5 gave _! entire att5tion to ! /udy ( electricity4 ,volta 0 n m]ely an inv5tor1 = he 0 "o ( ! greate/ sci5ti/s ( 8 p]iod1 end[$ ) an imag9ation :i* m>k$ him z a g5ius 9 creative "w4 ,by contribut+ ! electric batt]y1 he add$ ! greate/ impetus to rese>* 9 electrical sci5ce t x has ev] receiv$4 ,z has already be5 %[n1 !re began a p]iod ( en?usia/ic rese>* 9 ! g5]al field ( heat+ effects ( electric curr5t4 ,! electric arc 0 born 9 ! cradle ( ?is en?usiasm1 & 9 ! heat+ ( metals by electricity ! future inc&esc5t lamp _h its beg9n+4 ,betwe5 ! ye>s #ahda & #ahdh sev]al inv5tors attempt$ to make light-s\rces by heat+ metals4 ,^! crude lamps 7 op]at$ by means ( ,grove & ,buns5 electric cells1 b no practicable inc&esc5t filam5t lamps 7 br\ght out until ! developm5t ( ! electric dynamo suppli$ an adequate s\rce ( electric curr5t4 ,z electrical sci5ce progress$ ?r\gh ! cont9u$ ef=ts ( sci5tific m51 x f9ally became evid5t t an adequate supply ( electric curr5t c\ld be obta9$ by me*anical means2 t is1 by rotat+ conductors 9 su* a mann] t curr5t w\ld be g5]at$ )9 !m z !y cut ?r\gh a magnetic field4 ,ev5 ! pione] inv5tors ( electric lamps made great contributions to electrical practice by develop+ ! dynamo4 ,bru% develop$ a satisfactory dynamo co9cid5tal ) 8 inv5tion ( ! arc-lamp1 & 9 a simil> mann]1 ,edison made a great contribution to electrical practice 9 devis+ means ( g5]at+ & di/ribut+ electricity = ! purpose ( s]v+ 8 filam5t lamp4 ,illu/ration3 ,,direct ,,curr5t ,,arc ,mo/ ( ! light be+ emitt$ by ! positive 7upp]7 electrode ,illu/ration3 ,,flame ,,arc ,mo/ ( ! light be+ emitt$ by ! flame ,illu/ration3 ,,on ,,! ,,te/+-,,racks ,,( ,,! ,,manufactur] ,,( ,,inc&esc5t ,,filam5t ,,lamps ,?\s&s ( lamps are burn$ out = ! sake ( mak+ improvem5ts4 ,! electrical en]gy us$ is equival5t to t consum$ by a city ( #cj1jjj inhabitants ,edison 9 #ahgh attack$ ! problem ( produc+ light f a wire or filam5t heat$ electrically4 ,he us$ plat9um wire 9 8 fir/ exp]im5ts1 b its volatility & l[ melt+-po9t 7#cbjj;,f47 limit$ ! success ( ! lamps4 ,c>bon ) its extremely high melt+-po9t _h long attract$ att5tion & 9 #ahgi ,edison produc$ a c>bon filam5t by c>boniz+ a /rip ( pap]4 ,he seal$ ?is 9 a vessel ( glass f :i* ! air 0 exhau/$ & ! electric curr5t 0 l$ to ! filam5t ?r\gh plat9um wires seal$ 9 ! glass4 ,plat9um 0 us$ because its expansion & contraction is ab\t ! same z glass4 ,incid5tally1 _m improvem5ts 7 made 9 inc&esc5t lamps & ?irty ye>s pass$ be=e a mat]ial 0 f\nd to replace ! plat9um lead+-9 wires4 ,! co/ ( plat9um /eadily increas$ & f9ally 9 ! pres5t c5tury a sub/itute 0 made by ! use ( two metals ^: comb9$ expansion 0 ! same z t ( plat9um or glass4 ,9 #ahgi & #ahhj ,edison _h succe$$ 9 ov]com+ ! _m difficulties suffici5tly to give to ! _w a practicable inc&esc5t filam5t lamp4 ,ab\t ?is "t ,swan & ,/e>n 9 ,engl& _h also produc$ a successful lamp4 ,9 ,edison's e>ly exp]im5ts ) filam5ts he us$ plat9um wire coat$ ) c>bon b )\t mu* success4 ,he also made ?9 rods ( a mixture ( f9ely divid$ metals su* z plat9um & iridium mix$ ) su* oxides z magnesia1 zirconia1 & lime4 ,he ev5 coil$ plat9um wire ar\nd a piece ( "o ( ^! oxides1 ) ! aim ( obta9+ light f ! wire & f ! heat$ oxide4 ,h[ev]1 ^! exp]im5ts s]v$ little purpose besides indicat+ t ! filam5t 0 be/ if x consi/$ solely ( c>bon & t x %\ld be conta9$ 9 an evacuat$ vessel4 ,"o ( ! *ief difficulties 0 to make ! c>bon filam5ts4 ,"s ( ! pione]s1 su* z ,sawy] & ,mann1 attempt$ to cut ^! f a piece ( c>bon4 ,h[ev]1 ,edison & also ,swan turn$ _! att5tion to =m+ !m by c>boniz+ a fib] ( organic matt]4 ,filam5ts cut f pap] & ?reads ( cotton & silk 7 c>boniz$ = ?is purpose4 ,edison sc\r$ ! e>? = bett] mat]ials4 ,he tri$ a fibr\s grass f ,s\? ,am]ica & v>i\s k9ds ( bamboo f o!r p>ts ( ! _w4 ,?9 filam5ts ( split bamboo ev5tually prov$ ! be/ mat]ial up to t "t4 ,he made _m lamps conta9+ filam5ts ( ?is mat]ial1 & ev5 until #aiaj bamboo 0 us$ to "s ext5t 9 c]ta9 lamps4 ,( ^! e>ly days1 ,edison said3 ,x occurr$ to me t p]haps a filam5t ( c>bon c\ld be made to /& 9 seal$ glass vessels1 or bulbs1 :i* we 7 us+1 exhau/$ to a high vacuum4 ,sep>ate lamps 7 made 9 ?is way indep5d5t ( ! air-pump1 &1 9 ,octob]1 #ahgi1 we made lamps ( pap] c>bon1 & ) c>bons ( common sew+ ?read1 plac$ 9 a receiv] or bulb made entirely ( glass1 ) ! lead+-9 wires seal$ 9 by fusion4 ,! :ole ?+ 0 exhau/$ by ! ,spr5gel pump to ne>ly "o-million? ( an atmosph]e4 ,! filam5ts ( c>bon1 al?\gh naturally q fragile ow+ to _! l5g? & small mass1 _h a small] radiat+ surface & high] resi/ance ?an we _h d>$ hope4 ,we _h virtually rea*$ ! position & condition :]e ! c>bons 7 /able4 ,9 o!r words1 ! inc&esc5t lamp z we /ill "k x to-day #aijd1 9 ess5tially all its p>ticul>s un*ang$1 _h be5 born4 ,aft] ,edison's lat] success ) bamboo1 ,swan inv5t$ a process ( squirt+ filam5ts ( nitrocellulose into a coagulat+ liquid1 aft] :i* !y are c>boniz$4 ,v f9e uni=m filam5ts c be made by ?is process & al?\gh improvem5ts h be5 made f "t to "t1 ?is me?od has be5 employ$ ev] s9ce its inv5tion4 ,9 ^! lat] ye>s cotton is dissolv$ 9 a suitable solv5t su* z a solution ( z9c *loride & ?is mat]ial is =c$ ?r\gh a small diamond die4 ,?is ?read :5 h>d5$ appe>s simil> to cat-gut4 ,x is cut into prop] l5g?s & b5t ^u a =m4 ,x is !n imm]s$ 9 plumbago & heat$ to a high temp]ature 9 ord] to de/roy ! organic matt]4 ,a c>bon filam5t is ! result4 ,f ?is po9t to ! f9i%$ lamp _m op]ations are p]=m$1 b a discussion ( ^! w\ld lead f> afield4 ,! production ( a high vacuum is "o ( ! mo/ important processes & manufactur]s ( inc&esc5t lamps h ma/]$ ! art p]haps m ?or\ghly ?an any o!r manufactur]s4 ,at lea/1 _! exp]i5ce 9 ?is field made x possible = !m to produce quickly & on a l>ge scale su* devices z ,x-ray tubes dur+ ! rec5t w>4 ,dur+ ! e>ly ye>s ( inc&esc5t lamps1 improvem5ts 7 made f "t to "t :i* increas$ ! life & ! lum9\s effici5cy ( ! c>bon filam5ts1 b x 0 n until #aijf t any radical improvem5t 0 a*iev$4 ,9 t ye> 9 ?is c\ntry a process 0 devis$ :]eby ! c>bon filam5t 0 made m compact4 ,9 fact1 f its appe>ance x receiv$ ! "n metalliz$ filam5t4 ,^! c>bon filam5ts are prep>$ 9 ! same mann] z ! e>li] ones b are f9ally treat$ by heat+ 9 an atmosph]e ( hydroc>bons su* z coal-gas4 ,! filam5t is heat$ by electric curr5t & ! heat breaks d[n ! hydroc>bons1 ) ! result t c>bon is deposit$ ^u ! filam5t4 ,?is treat$ filam5t has a coat+ ( h>d c>bon & its electrical resi/ance is great] ?an t ( ! untreat$ filam5t4 ,! lum9\s effici5cy ( a c>bon filam5t is a function ( its temp]ature & x increases v rapidly ) increas+ temp]ature4 ,= ?is reason x is a con/ant aim to rea* high filam5t temp]atures4 ,( all ! mat]ials us$ 9 filam5ts up to ! pres5t "t1 c>bon possesses ! highe/ melt+-po9t 7p]haps z high z #gjjj;,f471 b ! c>bon filam5t z op]at$ 9 practice has a l[] effici5cy ?an any o!r filam5t4 ,?is is because ! highe/ temp]ature at :i* x c be op]at$ & /ill h a reasonable life is mu* l[] ?an t ( metallic filam5ts4 ,! inc&esc5t c>bon 9 ! evacuat$ bulb sublimes or volatilizes & deposits ^u ! bulb4 ,?is decreases ! size ( ! filam5t ev5tually to ! break+-po9t & ! black5+ ( ! bulb decreases ! output ( light4 ,! treat$ filam5t 0 f\nd to be a h>d] =m ( c>bon t did n volatilize z rapidly z ! untreat$ filam5t4 ,x imm$iately became possible to op]ate x at a high] temp]ature ) a result+ increase ( lum9\s effici5cy4 ,?is graphitiz$ c>bon filam5t lamp became kn[n z ! gem lamp 9 ?is c\ntry & _m p]sons h wond]$ ov] ! ^w gem4 ,! fir/ two lett]s /& = ,g5]al ,electric & ! la/ = metalliz$4 ,?is lamp 0 welcom$ ) en?usiasm 9 its day1 b ! day = c>bon filam5ts has pass$4 ,! adv5t ( inc&esc5t lamps ( high] effici5cy has made x uneconomical to use c>bon lamps = g5]al light+ purposes4 ,al?\gh ! treat$ c>bon filam5t 0 a great improvem5t1 its reign 0 cut %ort by ! appe>ance ( metal filam5ts4 ,9 #ahjc a new elem5t 0 discov]$ & nam$ tantalum4 ,x is a d>k1 lu/r\s1 h>d metal4 ,pure tantalum is h>d] ?an /eel2 x may be drawn into f9e wire2 & its melt+-po9t is v high 7ab\t #eajj;,f474 ,x is se5 to possess prop]ties desirable = filam5ts1 b = "s reason x did n attract att5tion = a long "t4 ,a c5tury elaps$ aft] its discov]y be=e von ,bolton produc$ ! fir/ tantalum filam5t lamp4 ,ow+ to ! l[ electrical resi/ance ( tantalum1 a filam5t 9 ord] to op]ate satisfactorily on a /&>d voltage mu/ be long & ?94 ,?is necessitates /or+ away a consid]able l5g? ( wire 9 ! bulb )\t p]mitt+ ! loops to come into contact ) ea* o!r4 ,aft] ! filam5ts h be5 9 op]ation = a few hundr$ h\rs !y become brittle & faults develop4 ,:5 exam9$ "u a microscope1 p>ts ( ! filam5t op]at$ on alt]nat+ curr5t appe> to be (fset4 ,! explanation ( ?is defect goes deeply into cry/all9e /ructure4 ,! tantalum filam5t 0 quickly foll[$ by osmium & by tung/5 9 ?is c\ntry4 ,! osmium filam5t appe>$ 9 #aije & its inv5tion is due to ,welsba*1 :o _h produc$ ! m>vel\s gas-mantle4 ,ow+ to its extreme brittl5ess1 osmium 0 f9ely divid$ & made into a pa/e ( organic mat]ial4 ,! filam5ts 7 squirt$ ?r\gh dies &1 aft] be+ =m$ & dri$1 !y 7 heat$ to a high temp]ature4 ,! organic matt] disappe>$ & ! f9e metallic p>ticles 7 s9t]$4 ,?is made a v brittle lamp1 b its high effici5cy s]v$ to introduce x4 ,9 #ahgj :5 ,s*eele discov]$ a new elem5t1 kn[n 9 ?is c\ntry z tung/51 no "o realiz$ t x 0 to revolutionize artificial light+ & to alt] ! c\rse ( "s ( ! byways ( civilization4 ,?is metal--:i* is kn[n z wolfram 9 ,g]many1 & to "s ext5t 9 ,engli%-speak+ c\ntries--is "o ( ! heavie/ ( elem5ts1 hav+ a specific gravity ( #ai4a4 ,x is #ej p] c5t4 heavi] ?an m]cury & ne>ly twice z heavy z lead4 ,x 0 e>ly us$ 9 ,g]man silv] to ! ext5t ( #a or #b p] c5t4 to make plat9oid1 an alloy possess+ a high resi/ance :i* v>ies only slightly z ! temp]ature *anges4 ,?is made an excell5t mat]ial = electrical resi/ors4 ,! melt+-po9t ( tung/5 is ab\t #ecej;,f41 :i* makes x desirable = filam5ts1 b x 0 v brittle z prep>$ 9 ! e>ly exp]im5ts4 ,x unites v readily ) oxyg5 & ) c>bon at high temp]atures4 ,! fir/ tung/5 lamps appe>$ on ! m>ket 9 #aijf1 b ^! conta9$ fragile filam5ts made by ! squirt+ process4 ,:5 ! squirt$ filam5t ( tung/5 p[d] & organic matt] 0 heat$ 9 an atmosph]e ( /eam & hydrog5 to remove ! b9d+ mat]ial1 a brittle filam5t ( tung/5 0 obta9$4 ,! fir/ lamps 7 co/ly & fragile4 ,aft] ye>s ( organiz$ rese>* tung/5 is n[ drawn into ! f9e/ wires1 possess+ a t5sile /r5g? p]haps great] ?an any o!r mat]ial4 ,filam5ts are n[ made into _m %apes & ! greate/ /rides 9 artificial light+ h be5 due to sci5tific rese>* on a huge scale4 ,! a*ievem5ts :i* comb9$ to p]fect ! tung/5 lamp to ! po9t :]e x has become ! ma9/ay ( electric light+ are n atta*$ to names 9 ! ,hall ( ,fame4 ,organization ( sci5tific rese>* 9 ! indu/rial laboratories is su* t (t5 _m p]sons contribute to ! developm5t ( an improvem5t4 ,fur!rmore1 "t is usually requir$ = a full p]spective ( applications ( sci5tific k4 ,9 ! e>ly days organiz$ rese>* 0 n practis$ & ! great developm5ts ( ^? days 7 ! works ( individuals4 ,to-day1 ev5 9 pure sci5ce1 "s ( ! greate/ contributions are made by indu/rial laboratories2 b sometimes ^! d n become kn[n to ! public = _m ye>s4 ,! :ole s*eme ( sci5tific developm5t has *ang$ mat]ially4 ,= example1 ! /ory ( ! developm5t ( ductile tung/51 :i* has revolutioniz$ light+1 is complex & m or less %r\d$ 9 secrecy at ! pres5t "t4 ,_m m5 h contribut$ t[>d ?is accompli%m5t & ! public at ! pres5t "t kn[s little m ?an ! fact t tung/5 filam5ts1 :i* 7 brittle ye/]day1 are n[ made ( ductile tung/5 wire drawn into ! f9e/ filam5ts4 ,! e>li] tung/5 filam5ts 7 made by ?ree rival processes4 ,by ! fir/1 a deposit ( tung/5 0 fla%$ on a f9e c>bon filam5t1 ! latt] be+ elim9at$ f9ally by heat+ 9 an atmosph]e ( hydrog5 & wat]-vapor4 ,by ! second1 colloidal tung/5 0 produc$ by op]at+ an arc betwe5 tung/5 electrodes "u wat]4 ,! f9ely divid$ tung/5 0 ga!r$1 p>tially dri$1 & squirt$ ?r\gh dies to =m filam5ts4 ,^! 7 !n s9t]$4 ,! ?ird 0 ! pa/e process already describ$4 ,^! me?ods produc$ fragile filam5ts1 b _! lum9\s effici5cy 0 high] ?an t ( previ\s ones4 ,h[ev]1 9 ?is c\ntry ductile tung/5 0 soon on its way4 ,an +ot ( tung/5 is subject$ to vigor\s swag+ until x takes ! =m ( a rod4 ,?is is f9ally drawn into wire4 ,mu* ( ?is developm5t "w 0 done by ! laboratories ( ! ,g5]al ,electric ,company & !y 7 de/9$ to contribute ano!r great improvem5t4 ,! black5+ ( ! lamp bulbs 0 due to ! evaporation ( tung/5 f ! filam5t4 ,all filam5ts up to ?is "t _h be5 conf9$ 9 evacuat$ bulbs & ! l[ pressure facilitates evaporation1 z is well kn[n4 ,x _h long be5 kn[n t an in]t gas 9 ! bulb w\ld r$uce ! evaporation & rem$y o!r defects2 h[ev]1 "u ^! conditions1 !re w\ld be a consid]able loss ( en]gy ?r\gh conduction ( heat by ! gases4 ,9 ! vacuum lamp ne>ly all ! electrical en]gy is conv]t$ into radiant en]gy1 :i* is emitt$ by ! filam5t & any dissipation ( heat is an en]gy loss4 ,a high vacuum 0 "o ( ! *ief aims up to ?is "t1 b a radical dep>ture 0 p5d+4 ,if an ord9>y tung/5-lamp bulb be fill$ ) an in]t gas su* z nitrog51 ! filam5t may be op]at$ at a v mu* high] temp]ature )\t any m det]ioration ?an takes place 9 a vacuum at a l[] temp]ature4 ,?is gives a m effici5t light b a less effici5t lamp4 ,! great] output ( light is comp5sat$ by losses by conduction ( heat ?r\gh ! gas4 ,9 o!r words1 a great deal m en]gy is requir$ by ! filam5t 9 ord] to rema9 at a giv5 temp]ature 9 a gas ?an 9 a vacuum4 ,h[ev]1 elaborate /udies ( ! dep5d5ce ( heat-losses ^u ! size & %ape ( ! filam5t & ( ! physics ( conduction f a solid to a gas1 e/abli%$ ! f\ndation = ! gas-fill$ tung/5 lamp4 ,! k ga9$ 9 ^! inve/igations indicat$ t a ?ick] filam5t lo/ a relatively less p]c5tage ( en]gy by conduction ?an a ?9 "o = equal am\nts ( emitt$ light4 ,h[ev]1 a practical filam5t mu/ h suffici5t resi/ance to be us$ safely on light+ circuits already e/abli%$ &1 !re=e1 ! l>ge diamet] & high resi/ance 7 obta9$ by mak+ a helical coil ( a f9e wire4 ,9 fact1 ! gas-fill$ tung/5 lamp may be ?\ght ( z an ord9>y lamp ) its long filam5t made into a %ort helical coil & ! bulb fill$ ) nitrog5 or argon gas4 ,?is developm5t 0 n accid5tal & f a sci5tific po9t ( view x is n spectacul>4 ,x did n m>k a new discov]y 9 ! same s5se z ! discov]y ( ,x-rays4 ,h[ev]1 x is an excell5t example ( ! great rew>ds :i* come to sy/ematic1 ?or\gh /udy ( r commonplace physical laws 9 respect to a giv5 condition4 ,su* a*ievem5ts are be+ duplicat$ 9 v>i\s l9es 9 ! laboratories ( ! indu/ries4 ,sci5tific rese>* is no long] monopoliz$ by educational in/itutions4 ,! mo/ elaborate & be/-equipp$ laboratories are to be f\nd 9 ! indu/ries sometimes surr\nd$ by ! smoke & noise & vigor\s activity :i* indicate t a*ievem5ts ( ! laboratory are on _! way to mank9d4 ,! smoke-lad5 indu/rial di/rict1 pulsat+ ) life1 is ! pr\d exhibit ( ! pres5t civilization4 ,x is ! creation ( ^? :o discov]1 organize1 & apply sci5tific facts4 ,b h[ _m appreciate ! debt t mank9d owes n only to ! individual :o d$icates 8 life to sci5ce b to ! f>-sight$ manufactur] :o risks 8 money 9 organiz$ que/ ( new b5efits = mank9d8 ,a glimpse into a va/ organization ( rese>*1 :i*1 = example1 has be5 ma9ly responsible = ! progress ( ! inc&esc5t lamp w\ld alt] ! attitude ( _m p]sons t[>d sci5ce & t[>d ! l>ge indu/rial companies4 ,! progress 9 ! developm5t ( electric inc&esc5t lamps is %[n 9 ! foll[+ table1 :]e ! dates & values are m or less approximate4 ,x %\ld be und]/ood t f #ahhj to ! pres5t "t !re has be5 a /eady progress1 :i* occasionally has be5 greatly augm5t$ by sudd5 /eps4 ,,approximate ,,values ,lum5s p] ,date ,filam5t ,temp]ature watt #ahhj ,c>bon #ccjj;,f4 #c4j #aijf ,c>bon 7graphitiz$7 #cdjj #d4e #aije ,tantalum #ceej #f4e #aije ,osmium #cfjj #g4e #aijf ,tung/5 7vacuum7 #cgjj #h4j #aiad ,tung/5 7gas-fill$7 up to #ecjj;,f4 #aj to #be ,?r\gh\t ! developm5t ( inc&esc5t filam5t lamps _m +5i\s exp]im5ts 7 made :i* result$ usually 9 light-s\rces ( sci5tific int]e/ b n ( practical value4 ,"o ( ! late/ is ! tung/5 arc 9 an in]t gas4 ,by means ( a heat+ coil1 a small arc is />t$ betwe5 two electrodes consi/+ ( tung/51 b ?is z yet has n be5 %[n to be practicable4 ,ano!r type ( filam5t lamp 0 develop$ by ,n]n/ 9 #ahig4 ,x 0 an +5i\s application ( ! peculi> prop]ties ( r>e-e>? oxides4 ,8 fir/ lamp consi/$ ess5tially ( a sl5d] rod ( magnesia4 ,?is sub/ance does n conduct electricity at ord9>y temp]atures1 b :5 heat$ to inc&esc5ce x becomes conduct+4 ,^u suffici5t heat+ ( ?is filam5t by ext]nal means :ile a prop] voltage is impress$ ^u x1 ! electric curr5t passes ?r\gh x & !reaft] ?is curr5t w ma9ta9 its temp]ature4 ,?us su* a filam5t becomes a conductor & w cont9ue to gl[ brilliantly by virtue ( ! electrical en]gy :i* x conv]ts into heat4 ,lat] lamps consi/$ ( gl[]s ab\t "o in* long made f a mixture ( zirconia & yttria1 & f9ally a mixture ( c]ia1 ?oria1 & zirconia 0 us$4 ,! gl[] is heat$ initially by a coil ( plat9um wire locat$ ne> x b n 9 contact ) x4 ,ow+ to ! fact t ?is gl[] decreases rapidly 9 resi/ance z its temp]ature is increas$1 x is necess>y to place 9 s]ies ) x a sub/ance :i* increases 9 resi/ance ) increas+ curr5t4 ,?is is call$ a balla/+ resi/ance & is usually an iron wire 9 a glass bulb conta9+ hydrog54 ,! heat] is cut out by an electromagnet :5 ! gl[] goes into op]ation4 ,?is lamp is a m>vel ( +5uity & :5 at its z5i? x 0 in/all$ to a consid]able ext5t4 ,its light is consid]ably :it] ?an t ( ! c>bon filam5t lamps4 ,h[ev]1 its doom 0 s\nd$ :5 metallic filam5t lamps appe>$4 ,an int]e/+ filam5t 0 develop$ by ,p>k] & ,cl>k by us+ z a core a small filam5t ( c>bon4 ,?is fla%$ 9 an atmosph]e conta9+ a vapor ( a comp\nd ( silicon1 became coat$ ) silicon4 ,?is filam5t 0 ( high specific resi/ance & appe>$ to h promise4 ,x has n be5 introduc$ comm]cially & d\btless x _c compete ) ! late/ tung/5 lamps4 ,electric inc&esc5t lamps are ! pres5t ma9/ay ( electric illum9ation &1 x might be /at$1 ( progress 9 light+4 ,wond]ful a*ievem5ts h be5 accompli%$ 9 o!r modes ( light+ & ! =ego+ /atem5t is n meant to depreciate ^? a*ievem5ts4 ,h[ev]1 ! inc&esc5t filam5t lamp has _m inh]5t advantages4 ,! light-s\rce is enclos$ 9 an air-tight bulb :i* makes = a safe1 conv5i5t lamp4 ,! filam5t is capable ( subdivision1 ) ! result t su* lamps v>y f ! m9ute/ sp>k ( ! smalle/ m9iature lamp to ! enorm\s output ( ! l>ge/ gas-fill$ tung/5 lamp4 ,! outputs ( ^! are respectively a fraction ( a lum5 & tw5ty-five ?\s& lum5s2 t is1 ! lum9\s int5sity v>ies f an equival5t ( a small fraction ( a /&>d c&le to a s+le light-s\rce emitt+ light equival5t to two ?\s& /&>d c&les4 ,/ati/ics are cold facts & are usually un9t]e/+ 9 a volume ( ?is "*1 b !y tell a /ory 9 a concise mann]4 ,! developm5t ( ! mod]n inc&esc5t lamp has increas$ ! int5sity ( light available ) a great decrease 9 co/1 & ?is progressive developm5t is %[n easily by tables4 ,= example1 s9ce ! adv5t ( ! tung/5 lamp ! av]age c&le-p[] & lum9\s effici5cy ( all ! lamps sold 9 ?is c\ntry has /eadily increas$1 :ile ! av]age wattages ( ! lamps h rema9$ virtually /ation>y4 ,,av]age ,,c&le-,,p[]1 ,,watts1 ,,& ,,effici5cy ,,( ,,all ,,! ,,lamps ,,sold ,,9 ,,?is ,,c\ntry ,lum5s ,ye> ,c&le-p[] ,watts p] watt #aijg #ah4j #ec #c4cc #aijh #ai4j #ec #c4eb #aiji #ba4j #eb #c4if #aiaj #bc4j #ea #d4db #aiaa #be4j #ea #d4hb #aiab #bf4j #di #e4bj #aiac #bi4d #dg #f4ac #aiad #ch4b #dh #g4hj #aiae #db4b #dg #h4gd #aiaf #de4h #di #i4fj #aiag #dh4g #ea #aj4ef ,x w be not$ t ! lum9\s int5sity ( inc&esc5t filam5t lamps has /eadily increas$ s9ce ! c>bon lamp 0 sup]s$$1 & t 9 a p]iod ( t5 ye>s ( organiz$ rese>* beh9d ! tung/5 lamp ! lum9\s effici5cy 7lum5s p] watt7 has trebl$4 ,9 o!r words1 ev]y?+ else rema9+ un*ang$1 ! co/ ( light 9 t5 ye>s 0 r$uc$ to "o ?ird4 ,b ! r$uction 9 co/ has be5 m ?an ?is1 z w be %[n lat]4 ,dur+ ! same span ( ye>s ! p]c5tage ( c>bon filam5t lamps ( ! total filam5t lamps sold decreas$ f #ajj p] c5t4 9 #aijg to #ac p] c5t4 9 #aiag4 ,at ! same "t ! p]c5tage ( tung/5 7,mazda7 lamps increas$ f virtually z]o 9 #aijg to ab\t #hg p] c5t4 9 #aiag4 ,! tantalum lamp _h no opportunity to become e/abli%$1 because ! tung/5 lamp foll[$ its appe>ance v closely4 ,9 #aiaj ! sales ( ! =m] rea*$ _! highe/ m>k1 :i* 0 only #c4e p] c5t4 ( all ! lamps sold 9 ! ,unit$ ,/ates4 ,f a l[ly beg9n+ ! numb] ( inc&esc5t filam5t lamps sold = use 9 ?is c\ntry has gr[n rapidly1 rea*+ ne>ly two hundr$ million 9 #aiai4 ,,xi ,,! ,,light ,,( ,,! ,,future ,9 view+ ! developm5t ( artificial light & its manifold effects ^u ! activities ( mank9d1 x is natural to look into ! future4 ,jules ,v]ne possess$ ! advantage ( be+ able to write into fiction :at 8 riot\s imag9ation dictat$1 & s mu* ( :at he pictur$ has come true t 8 success tempts "o to d likewise 9 prophesy+ ! future ( light+4 ,surely a =eca/ bas$ alone ^u ! pa/ a*ievem5ts & ! pres5t indications w fall %ort ( ! actual realizations ( ! future6 ,if ! imag9ation is p]mitt$ to view ! future )\t re/rictions1 _m app>5tly f>-fet*$ s*emes may be devis$4 ,x may be possible to turn to nature's supply ( daylight & to place "s ( x 9 /orage = night use4 ,"o million? "p ( daylight releas$ z desir$ at night w\ld illum9ate suffici5tly all ( man's nocturnal activities4 ,! fictioni/ ne$ n he$ ! sci5ti/'s inquiry z to h[ ?is daylight w\ld be bottl$4 ,in/ead ( giv+ "t to su* inquiries he w\ld pass on to ano!r s*eme1 :]eby e>? w\ld be belt$ ) optical devices s t day c\ld nev] leave4 ,:5 ! sun 0 %9+ 9 ,*9a its light w\ld be ga!r$ on a l>ge scale & s5t ea/w>d & we/w>d 9 ^! great optical pipe-l9es to ! regions ( d>kness1 ?us bani%+ night =ev]4 ,! writ] ( fiction ne$ n bo!r ) a consid]ation ( ! economic situation :i* w\ld dem& su* ef=ts4 ,?is l9e ( conjecture is int]e/+1 = x may sugge/ possibilities t[>d :i* ! pres5t tr5d ( artificial light+ does n po9t2 h[ev]1 ! au?or is con/ra9$ to treat ! future ( light-production on a some:at m cons]vative basis4 ,at ! pres5t "t ! light-s\rce ( *ief int]e/ 9 electric light+ is ! inc&esc5t filam5t lamp2 b its lum9\s effici5cy is limit$1 z has be5 %[n 9 a previ\s *apt]4 ,:5 light is emitt$ by virtue ( its temp]ature mu* invisible radiant en]gy accompanies ! visible en]gy4 ,! highe/ lum9\s effici5cy atta9able by pure temp]ature radiation w be rea*$ :5 ! temp]ature ( a normal radiator rea*es ! vic9ity ( #aj1jjj;,f4 to #aa1jjj;,f4 ,! melt+-po9ts ( metals are mu* l[] ?an ?is4 ,! tung/5 filam5t 9 ! mo/ effici5t lamps employ+ x is op]at+ ne> its melt+-po9t at ! pres5t "t4 ,c>bon is a mo/ attractive elem5t 9 respect to melt+-po9t1 = x melts at a temp]ature betwe5 #fjjj;,f4 & #gjjj;,f4 ,ev5 ?is is f> bel[ ! mo/ effici5t temp]ature = ! production ( light by means ( pure temp]ature radiation4 ,!re are possibilities ( high] effici5cy be+ obta9$ by op]at+ arcs or filam5ts "u pressure2 h[ev]1 x appe>s t highly effici5t light ( ! future w result f a radical dep>ture4 ,sci5ti/s are becom+ m & m intimate ) ! /ructure ( matt]4 ,!y are le>n+ secrets e ye> :i* app>5tly are lead+ to a fundam5tal k ( ! subject4 ,:5 ^! my/]ies are solv$1 :o c say t man w n be able to create elem5ts to suit 8 ne$s1 or at lea/ to alt] ! prop]ties ( ! elem5ts already available8 ,if he c\ld s alt] ! me*anism ( radiation t a hot metal w\ld radiate no invisible en]gy1 he w\ld h made a trem5d\s /ride ev5 9 ! production ( light by virtue ( high temp]ature4 ,?is prop]ty ( selective radiation is possess$ by "s elem5ts to a slight degree1 b if treatm5t c\ld enhance ?is prop]ty1 lum9\s effici5cy w\ld be greatly increas$4 ,c]ta9ly ! pr9ciple ( selectivity is a byway ( possibilities4 ,a c>eful /udy ( commonplace factors may result 9 a great /ep 9 light-production )\t ! creation ( new elem5ts or comp\nds1 j z su* a proc$ure d\bl$ ! lum9\s effici5cy ( ! tung/5 filam5t :5 ! gas-fill$ lamp appe>$4 ,!re are a few elem5ts /ill miss+1 accord+ to ! ,p]iodic ,law :i* has be5 s valuable 9 *emi/ry4 ,:5 ^! turn up1 !y may be f\nd to possess valuable prop]ties = light-production2 b ?is is a disc\rag+ byway4 ,x is natural to inquire :e!r or n any mode ( light-production n[ 9 use has a limit+ lum9\s effici5cy approa*+ ! ultimate limit :i* is impos$ by ! visibility ( radiation4 ,! eye is able to conv]t radiant en]gy ( diff]5t wave-l5g?s into c]ta9 fix$ proportions ( light4 ,= example1 radiant en]gy ( su* a wave-l5g? z to excite ! s5sation ( yell[-gre5 is ! mo/ effici5t & "o watt ( ?is en]gy is capable ( be+ conv]t$ by ! visual app>atus into ab\t #fbe lum5s ( light4 ,is ?is effici5cy ( conv]sion ( ! visual app>atus ev]la/+ly fix$8 ,= ! answ] x is necess>y to turn to ! physiologi/1 & d\btless he w\ld sugge/ ! curb+ ( ! imag9ation4 ,b is x un?9kable t ! visual processes w always be beyond ! control ( man8 ,h[ev]1 to turn aga9 to ! physics ( light-production1 !re are /ill sev]al processes ( produc+ light :i* are appeal+4 ,_m ye>s ago ,geissl]1 ,crookes1 & o!r sci5ti/s /udi$ ! spectra ( gases excit$ to inc&esc5ce by ! electric dis*>ge 9 s-call$ vacuum tubes4 ,! gases are plac$ 9 transp>5t glass or qu>tz tubes at r l[ pressures & a high voltage is impress$ ^u ! ends ( ^! tubes4 ,:5 ! pressure is suffici5tly l[1 ! gases w gl[ & emit light4 ,tw5ty-eight ye>s ago1 ,d4 ,mc,farlan ,moore develop$ ! nitrog5 tube1 :i* 0 actually in/all$ 9 v>i\s places4 ,b !re is su* a loss ( en]gy ne> ! ca?ode t %ort vacuum tubes ( ?is "* are v ineffici5t produc]s ( light4 ,effici5cy is greatly increas$ by l5g!n+ ! tubes1 s ,moore us$ tubes ( great l5g? & a r high voltage4 ,z a tube ( ?is sort is us$1 ! gas gradually disappe>s & x mu/ be repl5i%$4 ,9 ord] to repl5i% ! gas1 ,moore devis$ a valve = fe$+ gas automatically4 ,an advantage ( ?is mode ( light-production is t ! color or quality ( ! light may be v>i$ by v>y+ ! gas us$4 ,nitrog5 yields a p9ki% light2 neon an orange light2 & c>bon dioxide a :ite light4 ,moore's c>bon-dioxide tube is an excell5t sub/itute = daylight & has be5 us$ = ! discrim9ation ( colors :]e ?is is an important factor4 ,h[ev]1 = ?is purpose devices utiliz+ color-scre5s :i* alt] ! light f ! tung/5 lamp to a daylight quality are be+ us$ ext5sively4 ,! vacuum-tube me?od ( produc+ light has an advantage 9 ! selection ( a gas among a l>ge numb] ( possibilities1 & "s ( ! color effects ( ! future may be obta9$ by means ( x4 ,claude has lately work$ on light-production by vacuum tubes & has comb9$ ! neon tube ) ! m]cury-vapor tube4 ,! spectrum ( neon to a l>ge ext5t comp5sates = ! abs5ce ( r$ light 9 ! m]cury spectrum1 ) a result t ! mixture produces a m satisfactory light ?an t ( ei!r tube4 ,h[ev]1 ?is mode ( light-production has n prov$ practicable 9 its pres5t /ate ( developm5t4 ,fundam5tally ! limitations are ^? ( ! inh]5t spectral *>act]i/ics ( gases4 ,d\btless ! possibilities ( ! me*anisms ( ! tubes & ( comb9+ v>i\s gases h n be5 exhau/$4 ,fur!rmore1 if man ev] becomes capable ( controll+ to "s ext5t ! /ructure ( elem5ts & ( comp\nds1 ?is me?od ( light-production is p]haps m promis+ ?an o!rs ( ! pres5t day4 ,!re is ano!r attractive me?od ( produc+ light & x has n escap$ ! writ] ( fiction4 ,h4 ,g4 ,wells1 ) 8 r>e skill & ) ! lic5se s (t5 envi$ by ! writ] ( facts1 has drawn ^u ! *>act]i/ics ( fluoresc5ce & phosphoresc5ce4 ,9 8 /ory ,! ,fir/ ,m5 9 ! ,moon1 ! inhabitants ( ! moon illum9ate _! cav]ns by utiliz+ ?is ph5om5on4 ,a fluoresc5t liquid 0 prep>$ 9 l>ge quantities4 ,x emitt$ a brilliant phosphoresc5t gl[ & :5 x spla%$ on ! feet ( ! e>?-m5 x felt cold1 b x gl[$ = a long "t4 ,?is is a possibility ( ! future & _m h _h visions ( su* light+4 ,if ! ceil+ ( a coal-m9e 0 l9$ ) gl[+ fireflies or ) phosphoresc5t mat]ial excit$ 9 "s mann]1 x w\ld be possible to see fairly well ) ! d>k-adapt$ eyes4 ,?is leads to ! class ( ph5om5a includ$ "u ! g5]al t]m lum9esc5ce4 ,! def9ition ( ?is t]m is n ?or\ghly agre$ ^u1 b light produc$ 9 ?is mann] does n dep5d ^u temp]ature 9 ! s5se t a gl[+ tung/5 filam5t emits light because x is suffici5tly hot4 ,a phosphorus mat* rubb$ 9 ! moi/ palm ( ! h& is se5 to gl[1 al?\gh x is at an ord9>y temp]ature4 ,?is may be t]m$ *emi-lum9esc5ce4 ,sidot bl5de1 ,balma9's pa9t1 & _m o!r comp\nds1 :5 illum9at$ ) ord9>y light1 & especially ) ultra-violet & violet rays1 w cont9ue to gl[ = a long "t4 ,despite _! brightness !y w be cold to ! t\*4 ,?is ph5om5on w\ld be t]m$ photo-lum9esc5ce1 al?\gh x is bett] kn[n z phosphoresc5ce4 ,x %\ld be not$ t ! latt] t]m 0 c>elessly orig9at$1 = phosphorus has no?+ to d ) x4 ,! gl[ ( ! ,geissl] tube or electrically excit$ gas at l[ pressure w\ld be an example ( electro-lum9esc5ce4 ,! lum9osity ( v>i\s salts 9 ! ,buns5-flame is due to s-call$ lum9esc5ce & !re are _m o!r examples ( light-production :i* are includ$ 9 ! same g5]al class4 ,inasmu* z light is emitt$ f comp>atively cold bodies 9 ^! cases1 x is popul>ly kn[n z cold light4 ,!re are _m in/ances ( light be+ emitt$ )\t be+ accompani$ by appreciable am\nts ( invisible radiant en]gy & x is natural to hope = practical possibilities 9 ?is direction4 ,z yet little is kn[n reg>d+ ! effici5cy ( light-production by phosphoresc5ce4 ,! lum9\s effici5cy ( ! radiant en]gy emitt$ by phosphoresc5t sub/ances has be5 /udi$1 b x seems /range t among ! va/ works on phosphoresc5t ph5om5a1 sc>cely any m5tion is made ( ! effici5cy ( produc+ light 9 ?is mann]4 ,= example1 assume t phosphoresc5t z9c sulphide is excit$ by ! light f a m]cury-arc4 ,all ! en]gy fall+ ^u x is n capable ( excit+ phosphoresc5ce1 z may be readily %[n4 ,assum+ t a kn[n am\nt ( radiant en]gy ( a c]ta9 wave-l5g? has be5 p]mitt$ to fall ^u ! phosphoresc5t mat]ial1 !n 9 ! d>k ! latt] may be se5 to gl[ = a long "t4 ,an int]e/+ po9t to inve/igate is ! relation ( ! output to input2 t is1 ! ratio ( ! total emitt$ light to ! total excit+ en]gy4 ,?is is a neglect$ aspect 9 ! /udy ( light-production by ?is means4 ,! firefly has be5 prais$ f> & wide z ! ideal light-s\rce4 ,x is an effici5t radiator ( light1 = its light is cold2 t is1 x does n appe> to be accompani$ by invisible radiant en]gy4 ,b little is said ab\t its effici5cy z a light-produc]4 ,:o kn[s h[ mu* fuel its light+-plant consumes8 ,! *emi/ry ( light-production by liv+ organisms is be+ unravel$ & ?is "p ( ! ph5om5on w likely be laid b>e be=e long4 ,= an equal am\nt ( en]gy radiat$1 ! firefly emits a great _m times m light ?an ! mo/ effici5t lamp 9 use at ! pres5t "t1 b be=e ! firefly is pron\nc$ ideal1 ! effici5cy ( its light-produc+ process mu/ be kn[n4 ,!re are _m ways ( excit+ phosphoresc5ce & fluoresc5ce1 ! latt] be+ m]ely an un5dur+ phosphoresc5ce1 :i* ceases :5 ! excit+ en]gy is cut (f4 ,ultra-violet1 violet1 & blue rays are g5]ally ! mo/ effective radiant en]gy = excitation purposes4 ,x-rays & ! high-frequ5cy dis*>ge are also p[]ful excitants4 ,z already /at$1 virtually no?+ is kn[n ( ! effici5cy ( ?is mode ( light-production or ( ! me*anism )9 ! sub/ance1 b on ! :ole x is a rem>kable ph5om5on4 ,radium is also a possibility 9 light-production & 9 fact has be5 practically employ$ = ?is purpose = sev]al ye>s4 ,x or "o ( its comp\nds is mix$ ) a phosphoresc5t sub/ance su* z z9c sulphide & ! latt] gl[s cont9u\sly4 ,inasmu* z ! life ( "s ( ! radium products is v long1 su* a me?od ( illum9at+ wat*-dials1 scales ( in/rum5ts1 etc41 is v practicable :]e !y are to be read by eyes adapt$ to d>kness & consequ5tly highly s5sitive to light4 ,:e!r or n radium w be manufactur$ by ! ton 9 ! future c only conjectur$4 ,ow+ to ! limitations impos$ by physical laws ( radiation & by ! physiological processes ( vision ! highe/ lum9\s effici5cy obta9able by heat+ solid mat]ials is only ab\t #ae p] c5t4 ( ! lum9\s effici5cy ( ! mo/ lum9\s radiant en]gy4 ,at pres5t !re are no mat]ials available :i* may be op]at$ at ! temp]ature necess>y to rea* ev5 ?is effici5cy4 ,great progress 9 ! future ( light-production z indicat$ by pres5t k appe>s to lie 9 ! production ( light :i* is unaccompani$ by invisible radiant en]gy4 ,at pres5t su* ph5om5a z fluoresc5ce1 phosphoresc5ce1 ! light ( ! firefly1 *emi-lum9esc5ce1 etc41 are examples ( ?is k9d ( light-production4 ,( c\rse1 if sci5ce ev] obta9s control ov] ! con/itution ( matt]1 _m difficulties w disappe>2 = !n man w n be dep5d5t ^u ! elem5ts & comp\nds n[ available b w be able to modify !m to suit 8 ne$s4 ,,xii ,,light+ ,,! ,,/reets ,9 ?is age ( brilliantly light$ b\lev>ds & great :ite ways flood$ ) light f %op-w9d[s1 electric signs1 & /reet-lamps1 x is difficult to visualize ! gloom :i* %r\d$ ! /reets a c5tury ago4 ,z ! belat$ p$e/rian walks along ! suburban highways 9 comp>ative safety "u adequate artificial light+1 he w realize ! great influ5ce ( artificial light ^u civilization if he recalls t n m ?an two c5turies ago 9 ,london x 0 a common practice 444 t a hundr$ or m 9 a company1 "y & old1 w\ld make nightly invasions ^u h\ses ( ! weal?y to ! int5t to rob !m & t :5 night 0 come no man dur/ adv5ture to walk 9 ! /reets4 ,inhabitants ( ! cities ( ! pres5t "t are incl9$ to ?9k t crime is common on ! /reets at night1 b :at w\ld x be )\t adequate artificial light8 ,two c5turies ago 9 a city l ,london a smok+ grease-lamp1 a c&le1 or a basket ( p9e knots "h & !re af=d$ ! only /reet-light+1 & ^! 7 ext+ui%$ by elev5 o'clock4 ,lawlessness 0 hat*$ & hidd5 by d>kness1 & ev5 ! lant]n or tor* s]v$ m to m>k ! victim ?an to protect him4 ,x has be5 said 9 describ+ ! conditions ( ! age ( d>k /reets t ev]ybody sign$ 8 w & 0 prep>$ = dea? be=e he left 8 home4 ,by comp>ison ) ! pres5t1 "o is aga9 enc\rag$ to believe t ! _w gr[s bett]4 ,d\btless1 artificial light project$ into ! crannies has _h some?+ to d ) ?is *ange4 ,adequate /reet-light+ is really a product ( ! tw5tie? c5tury1 b ?r\gh\t ! n9ete5? c5tury progress 0 /eadily made f ! beg9n+ ( gas-light+ 9 #ahjg4 ,9 prec$+ c5turies crude light+ 0 employ$ "h & !re b n g5]ally by ! public au?orities4 ,9 ! e>lie/ c5turies ( writt5 hi/ory little is said ( /reet-light+4 ,9 ^? days man 0 n s mu* incl9$ to improve ^u nature1 beyond protect+ himself f ! elem5ts1 & he light$ ! /reets m z a fe/ive outbur/ ?an z an economic proposition4 ,nev]!less1 9 ! e>ly writ+s occasionally !re are indications t 9 ! c5t]s ( advanc$ civilization "s ef=ts 7 made to light ! /reets4 ,! old ,syrian city ( ,antio*1 :i* 9 ! f\r? c5tury ( ! ,*ri/ian era conta9$ ab\t f\r hundr$ ?\s& inhabitants1 appe>s to h _h light$ /reets4 ,libanius1 :o liv$ 9 ! e>ly ye>s ( t c5tury1 wrote3 ,! light ( ! sun is succe$$ by o!r lights1 :i* are f> sup]ior to ! lamps light$ by ,egyptians on ! fe/ival ( ,m9]va ( ,sais4 ,! night ) u diff]s f ! day only 9 ! appe>ance ( ! light2 ) reg>d to labor & employm5t1 ev]y?+ goes on well4 ,al?\gh app>5tly labor 0 n on a /rike1 ! soldi]s caus$ di/urbances1 = 9 ano!r passage he tells ( riot\s soldi]s :o cut ) _! swords ! ropes f :i* 7 susp5d$ ! lamps t af=d$ light 9 ! night-"t1 to %[ t ! ornam5ts ( ! city ought to give way to !m4 ,ano!r writ] 9 describ+ a dispute betwe5 two religi\s adh]5ts ( oppos$ cre$s /at$ t !y qu>rel$ till ! /reets 7 light$ & ! cr[d ( onlook]s broke up1 b n until !y spat 9 ea* o!r's face & retir$4 ,?us x is se5 t artificial light & civilization may advance1 ev5 ?\gh "s human traits rema9 fundam5tally un*ang$4 ,?r\gh\t ! next ?\s& ye>s !re 0 little attempt to light ! /reets4 ,iron baskets ( burn+ wood1 primitive oil-lamps1 & c&les 7 us$ to "s ext5t1 b dur+ all ^! c5turies !re 0 no attempt on ! "p ( ! gov]nm5t or ( individuals to light ! /reets 9 an organiz$ mann]4 ,9 #adag ! ,mayor ( ,london orda9$ lan?orns ) lights to bee hang$ out on ! w9t] ev5+s betwixt ,hall[tide & ,c&lemasse4 ,?is 0 dur+ ! fe/ive season1 s p]haps /reet-light+ 0 n ! sole aim4 ,e>ly 9 ! sixte5? c5tury1 ! /reets ( ,p>is be+ infe/$ ) robb]s1 ! inhabitants 7 ord]$ to keep lights burn+ 9 ! w9d[s ( all h\ses t front$ on ! /reets4 ,= ab\t ?ree c5turies ! citiz5s ( ,london1 & d\btless ( ,p>is & ( o!r cities1 7 rem9d$ f "t to "t 9 (ficial m&ates on pa9s & p5alties to hang out _! lan?orns at ! appo9t$ "t4 ,! wat*man 9 long coat ) halb]d & lant]n 9 h& supplem5t$ ^! m&ates z he made 8 r\nds by1 ,a light "h1 maids1 hang out y\r lights1 ,& see y\r horns be cle> & bright1 ,t s y\r c&le cle> may %9e1 ,cont9u+ f six till n9e2 ,t hone/ m5 t walk along ,may see to pass safe )\t wrong4 ,9 #affh1 :5 "s regulations 7 made = improv+ ! /reets ( ,london1 ! inhabitants 7 ord]$ = ! safety & peace ( ! city to hang out c&les duly to ! accu/om$ h\r4 ,app>5tly ?is me?od ( obta9+ light+ = ! /reets 0 n met by ! en?usia/ic support ( ! p1 = dur+ ! next few decades ! ,"l ,mayor 0 busy issu+ ?reats & comm&s4 ,9 #afgi he proclaim$ ! neglect ( ! inhabitants ( ?is city 9 hang+ & keep+ out _! lights at ! accu/om$ h\rs1 accord+ to ! good & anci5t usage ( ?is ,city & ,acts ( ! ,common ,c\ncil on t behalf4 ,! result ( ?is neglect 0 :5 nights d>k5$ ! /reets !n w&]$ =? ! sons ( ,belial1 fl[n ) insol5ce & w9e4 ,9 #afid ,hemig pat5t$ a reflector :i* p>tially surr\nd$ ! op5 flame ( a :ale-oil lamp & possess$ a hole 9 ! top :i* aid$ v5tilation4 ,he obta9$ ! exclusive rights ( light+ ,london = a p]iod ( ye>s & und]took to place a light be=e e t5? door1 betwe5 ! h\rs ( six & twelve o'clock1 f ,mi*aelmas to ,lady ,day4 ,8 ef=t 0 a wor?y "o1 b he 0 oppos$ by a c]ta9 faction1 :i* 0 successful 9 obta9+ a )drawal ( 8 lic5se 9 #agaf4 ,aga9 ! burd5 ( light+ ! /reets 0 ?ru/ ^u ! resid5ts & f9es 7 impos$ = neglig5ce 9 ?is respect4 ,b ?is proc$ure aft] a few m ye>s ( desultory light+ 0 aga9 f\nd to be unsatisfactory4 ,9 #agbi c]ta9 individuals contract$ to light ! /reets ( ,london by tax+ ! resid5ts & paid ! city = ?is monopoly4 ,h\sehold]s 7 p]mitt$ to hang out a lant]n or a c&le or to pay ! company = do+ s4 ,b robb]ies increas$ s rapidly t 9 #agcf ! ,"l ,mayor & ,common ,c\ncil petition$ ,p>liam5t to erect lamps = light+ ! city4 ,an act 0 pass$ accord+ly1 giv+ !m ! privilege to erect lamps :]e !y saw fit & to burn !m f sunset to sunrise4 ,a *>ge 0 made to ! resid5ts1 on a slid+ scale dep5d+ ^u ! rate ( r5tal ( ! h\ses4 ,z a consequ5ce five ?\s& lamps 7 soon in/all$4 ,9 #agch !re 7 fifte5 ?\s& /reet lamps 9 ,london & !y 7 burn$ an av]age ( five ?\s& h\rs annually4 ,9 ! annals ( ^! e>ly times /reet-light+ is almo/ inv>iably ! result ( an attempt to r$uce ! numb] ( robb]ies & o!r crimes4 ,9 appeal+ = m /reet-lamps 9 #agdd ! ,"l ,mayor & ald]m5 ( ,london 9 a petition to ! k+1 /at$ t div]s conf$]acies ( great numb]s ( evil-dispos$ p]sons1 arm$ ) bludgeons1 pi/ols1 cutlasses1 & o!r dang]\s weapons1 infe/ n only ! private lanes & passages1 b likewise ! public /reets & places ( public conc\rse1 & commit mo/ d>+ outrages ^u ! p]sons ( y\r ,maje/y's good subjects1 ^: affairs oblige !m to pass ?r\gh ! /reets1 by t]rify+1 robb+ & w\nd+ !m2 & ^! facts are frequ5tly p]petrat$ at su* times z 7 h]et(ore deem$ h\rs ( security4 ,x has already be5 se5 t gas-light+ 0 introduc$ 9 ! /reets ( ,london = ! fir/ "t 9 #ahjg4 ,?is m>ks ! real beg9n+ ( public-s]vice light+ companies4 ,9 ! next decade int]e/ 9 /reet-light+ by means ( gas 0 awak5$ on ! ,cont95t1 & x 0 n long be=e ?is new phase ( civilization 0 well "u way4 ,al?\gh ?is fir/ gas-light+ 0 done by ! use ( op5 flames1 x 0 a great improvem5t ov] all ! prec$+ ef=ts4 ,lawlessness did n disappe> entirely1 ( c\rse1 & p]haps x nev] w1 b x skulk$ 9 ! back /reets4 ,a controll+ influ5ce _h n[ appe>$4 ,b e>ly innovations 9 light+ did n escape criticism & opposition4 ,9 fact1 innovations to-day are n always receiv$ by unanim\s cons5t4 ,!re 7 _m 9 ^? e>ly days :o felt t :at 0 good = !m %\ld be good en\gh = ! y\ng] g5]ation4 ,! desc5dants ( ^! oppon5ts are pres5t to-day b =tunately 9 dim9i%+ numb]s4 ,x has be5 %[n t 9 ,philadelphia 9 #ahcc a proposal to in/all a gas-plant 0 met ) a prote/ sign$ by _m prom95t citiz5s4 ,a few p>agraphs ( an article entitl$ ,argum5ts aga9/ ,light :i* appe>$ 9 ! ,cologne ,zeitung 9 #ahaf indicate ! "* ( ! objections rais$ aga9/ /reet-light+4 #a ,f ! !ological /&po9t3 ,artificial illum9ation is an attempt to int]f]e ) ! div9e plan ( ! _w1 :i* has preorda9$ d>kness dur+ ! night-"t4 #b ,f ! judicial /&po9t3 ,^? p :o d n want light ought n to be compell$ to pay = its use4 #c ,f ! m$ical /&po9t3 ,! emanations ( illum9at+ gas are injuri\s4 ,moreov]1 illum9at$ /reets w\ld induce p to rema9 lat] out ( doors1 lead+ to an increase 9 ailm5ts caus$ by colds4 #d ,f ! moral /&po9t3 ,! fe> ( d>kness w vani% & drunk5ness & depravity increase4 #e ,f ! viewpo9t ( ! police3 ,! horses w get fright5$ & ! ?ieves embold5$4 #f ,f ! po9t ( view ( national economy3 ,great sums ( money w be export$ to =eign c\ntries4 #g ,f ! po9t ( view ( ! common p3 ,! con/ant illum9ation ( /reets by night w rob fe/ive illum9ations ( _! *>m4 ,! =ego+ objections require no comm5t1 = !y speak volumes p]ta9+ to ! ?\ghts & activities ( m5 a c5tury ago4 ,x is difficult to believe t civilization has travel$ s f> 9 a s+le c5tury1 b f ?is e>ly beg9n+ ( /reet-light+ social progress receiv$ a great impetus4 ,artificial light-s\rces 7 feeble at t "t1 b !y made ! /reets saf] & by means ( !m social int]c\rse 0 ext5d$4 ,! p increas$ _! h\rs ( activity & comm]ce1 indu/ry1 & k grew apace4 ,! op5 gas-jet & k]os5e-flame lamps held =? on ! /reets until )9 ! memory ( middle-ag$ p]sons ( to-day4 ,! lamplight] ) 8 ladd] is /ill fre% 9 memory4 ,_m ( ! t[ns & villages h nev] be5 light$ by gas1 = !y /epp$ f ! oil-lamp to ! electric lamp4 ,! gas-mantle has made x possible = gas-light+ to cont9ue z a competitor ( electric-light+ = ! /reets4 ,9 #ahgg ,mr4 ,bru% illum9at$ ! ,public ,squ>e ( ,clevel& ) a numb] ( arc-lamps1 & ^! met ) su* success t )9 a %ort "t two hundr$ & fifty ?\s& op5-arc lamps 7 in/all$ 9 ?is c\ntry1 involv+ an inve/m5t ( millions ( doll>s4 ,add+ to ?is inve/m5t a mu* great] "o 9 c5tral-/ation equipm5t1 a v l>ge inve/m5t is se5 to h result$ f ?is s+le developm5t 9 light+4 ,?is op5-arc lamp 0 ! fir/ p[]ful light-s\rce available &1 appe>+ sev]al ye>s be=e ! gas-mantle1 x ?reat5$ to monopolize /reet-light+4 ,x consum$ ab\t #ejj watts & _h a maximum lum9\s int5sity ( ab\t #abjj c&les at an angle ( ab\t #de degrees4 ,its *ief disadvantage 0 its di/ribution ( light1 ma9ly at ?is angle ( #de degrees1 :i* result$ 9 a spot ( light ne> ! lamp & little light at a di/ance4 ,a satisfactory /reet-light+ unit mu/ emit its light *iefly j bel[ ! horizontal 9 ^? cases :]e ! lamps mu/ be spac$ f> ap>t = economical reasons4 ,on ref]r+ to ! *apt] on ! electric arc x w be se5 t ! upp] 7positive7 c>bon ( ! op5-arc emits mo/ ( ! light4 ,?us mo/ ( ! light t5ds to be s5t d[nw>d1 b ! l[] c>bon ob/ructs "s ( ?is ) a result+ d>k spot b5ea? ! lamp4 ,! gas-mantle foll[$ closely aft] ! arrival ( ! c>bon arc & is responsible = ! exi/5ce ( gas-light+ on ! /reets at ! pres5t "t4 ,x is a l>ge s\rce ( light & !re=e its light _c be controll$ by mod]n accessories z well z ! light f small] s\rces1 su* z ! arc or conc5trat$-filam5t lamp4 ,z a consequ5ce1 !re is m>k$ unev5ness ( illum9ation along ! /reets unless ! gas-mantle units are spac$ r closely4 ,ev5 ) ! op5-arc1 )\t special light-controll+ equipm5t !re is ab\t a ?\s& times ! int5sity ne> ! lamps :5 plac$ on ! corn]s ( ! block z !re is midway betwe5 !m4 ,9 #ahgi ! inc&esc5t filam5t lamp 0 introduc$ & x began to appe> on ! /reets 9 a %ort "t4 ,x 0 a feeble1 ineffici5t light-s\rce1 comp>$ ) ! arc-lamp1 b x _h ! advantage ( be+ in/all$ on a small bracket4 ,z a consequ5ce ( simplicity ( op]ation1 ! inc&esc5t lamp 0 in/all$ to a consid]able ext5t1 especially 9 ! suburban di/ricts4 ,illu/ration3 ,,! ,,moore ,,nitrog5 ,,tube ,9 lobby ( ,madison ,squ>e ,g>d5 ,illu/ration3 ,,c>bon-,,dioxide ,,tube ,,= ,,accurate ,,color-,,mat*+ ,illu/ration3 ,,mod]n ,,/reet ,,light+ ,tunnels ( light bor+ ?r\gh ! d>kness provide safe *annels = mod]n traffic ,! op5-arc lamp possess$ ! disadvantage ( emitt+ a v un/eady light & ( consum+ ! c>bons s rapidly t daily trimm+ 0 (t5 necess>y4 ,9 #ahic ! enclos$ arc appe>$ & al?\gh x consum$ z mu* electrical en]gy z ! op5-arc & emitt$ consid]ably less light1 x possess$ ! great advantage ( op]at+ a week )\t requir+ a r5ewal ( c>bons4 ,by surr\nd+ ! arc by means ( a glass globe1 little oxyg5 c\ld come 9 contact ) ! c>bons & !y 7 n consum$ v rapidly4 ,! light 0 fairly /eady & ^! arcs op]at$ satisfactorily on alt]nat+ curr5t4 ,! latt] feature simplifi$ ! g5]at+ & di/ribut+ equipm5t ( ! c5tral /ation4 ,! magnetite or lum9\s arc-lamp next appe>$ & met ) consid]able success4 ,x 0 m effici5t ?an ! prec$+ lamps b 0 h&icapp$ by be+ solely a direct-curr5t device4 ,^? famili> ) ! g5]ation & di/ribution ( electricity w realize ?is disadvantage4 ,h[ev]1 its lum9\s int5sity j bel[ ! horizontal 0 ab\t #gjj c&les & its g5]al di/ribution ( light 0 fairly satisfactory4 ,lat] ! flame-arcs began to appe> & !y 7 in/all$ to "s ext5t4 ,! arc-lamp has s]v$ well 9 /reet-light+ f ! ye> #ahgg1 :5 ! op5-arc 0 introduc$1 until ! pres5t "t1 :5 ! lum9\s-arc is ! *ief survivor ( all ! arc-lamps4 ,! c>bon inc&esc5t filam5t lamp 0 us$ ext5sively until #aiji1 :5 ! tung/5 filam5t lamp began to replace x v rapidly4 ,h[ev]1 x 0 n until #aiad1 :5 ! gas-fill$ tung/5 lamp appe>$1 t ?is type ( light-s\rce c\ld compete ) arc-lamps on ! basis ( effici5cy4 ,! helical con/ruction ( ! filam5t made x possible to conf9e ! filam5t ( a high-int5sity tung/5 lamp 9 a small space & = ! fir/ "t a high degree ( control ( ! light ( /reet lamps 0 possible4 ,prismatic refractors 7 design$1 some:at on ! pr9ciple ( ! ligh?\se refractor1 s t ! light w\ld be emitt$ l>gely j bel[ ! horizontal4 ,?is type ( di/ribution builds up ! illum9ation at di/ant po9ts betwe5 successive /reet lamps1 :i* is v desirable 9 /reet-light+4 ,! inc&esc5t filam5t lamp possesses _m advantages ov] o!r sy/ems4 ,x is effici5t2 capable ( subdivision2 op]ates on direct & alt]nat+ curr5t2 requires little att5tion2 & is capable ( mo/ successful use ) light-controll+ app>atus4 ,accord+ to ! reports ( ! ,dep>tm5t ( ,comm]ce ! numb] ( electric arc-lamps = /reet-light+ suppli$ by public electric-light plants decreas$ f #cdh1fdc 9 #aiab to #bef1hch 9 #aiag1 :ile ! numb] ( electric inc&esc5t filam5t lamps increas$ f #fha1ieg 9 #aiab to #a1chi1chb 9 #aiag4 ,/reet-light+ is n only a re9=cem5t = ! police b x decreases accid5ts & has come to be look$ ^u z an adv]tis+ m$ium4 ,9 ! d[nt[n di/ricts ! high-int5sity :ite-way light+ is fe/ive4 ,! ornam5tal /reet lamps h possibilities 9 mak+ ! /reets attractive & 9 illum9at+ ! build+s4 ,h[ev]1 x is to be hop$ t 9 ! pres5t age ! /reets ( cities & t[ns w be cle>$ ( ! ragg$ equipm5t ( ! telephone & light+ companies4 ,^! may be plac$ 9 ! alleys or und]gr\nd1 leav+ ! /reets beautiful by day & glorifi$ at night by ! tor*es ( advanc$ civilization4 ,,xiii ,,ligh?\ses ,at ! pres5t "t ?\s&s ( ligh?\ses1 light-%ips1 & light-buoys guide ! navigator along ! wat]ways & into h>bors & w>n him ( dang]\s %oals4 ,_m wond]ful feats ( eng9e]+ are involv$ 9 _! con/ruction & 9 no field ( artificial light+ has m +5uity be5 display$ 9 devis+ p[]ful beams ( light4 ,_m ( ^! beacons ( safety are automatic 9 op]ation & require little att5tion4 ,x has be5 said t no?+ indicates ! lib]ality1 prosp]ity1 or intellig5ce ( a nation m cle>ly ?an ! facilities :i* x af=ds = ! safe approa* ( ! m>9] to its %ores4 ,surely ^! m>9e lights are important factors 9 mod]n navigation4 ,! fir/ ligh?\ses 7 beacon-fires ( burn+ wood ma9ta9$ by prie/s = ! b5efit ( ! e>ly comm]ce 9 ! ea/]n "p ( ! ,m$it]ranean ,sea4 ,z e>ly z ! sev5? c5tury be=e ,*ri/ ^! beacon-fires 7 m5tion$ 9 writ+s4 ,9 ! ?ird c5tury be=e ! ,*ri/ian era a t[] said to be ( a great height 0 built on a small isl& ne> ,alex&ria dur+ ! reign ( ,ptolemy ,,ii4 ,! t[] 0 nam$ ,ph>os1 :i* is ! orig9 ( ! t]m ph>ology appli$ to ! sci5ce ( ligh?\se con/ruction4 ,cs>1 :o visit$ ,alex&ria two c5turies lat]1 describ$ ! ,ph>os z a t[] ( great height1 ( wond]ful con/ruction4 ,fire 0 kept burn+ 9 x night & day & ,pl9y said ( x1 ,dur+ ! night x appe>s z bright z a />1 & dur+ ! day x is di/+ui%$ by ! smoke4 ,app>5tly ?is t[] s]v$ z a ligh?\se = m ?an a ?\s& ye>s4 ,x 0 f\nd 9 ru9s 9 #acdi4 ,?r\gh\t succe$+ c5turies _m t[]s 7 built1 b little att5tion 0 giv5 to ! developm5t ( light-s\rces & optical app>atus4 ,! fir/ ligh?\se 9 ! ,unit$ ,/ates & p]haps on ! ,we/]n cont95ts 0 ! ,bo/on ,light1 :i* 0 complet$ 9 #agaf4 ,a few days aft] x 0 put into op]ation a news item 9 a ,bo/on pap] h]ald$ ! notewor?y ev5t z foll[s3 ,by virtue ( an ,act ( ,assembly made 9 ! ,fir/ ,ye> ( ,8 ,maje/y's ,reign1 ,= ,build+ & ,ma9ta9+ a ,light ,h\se ^u ! ,great ,brew/] 7call$ ,beacon-,isl&7 at ! ,entrance ( ! ,h>b\r ( ,bo/on1 9 ord] to prev5t ! loss ( ! ,lives & ,e/ates ( ,8 ,maje/y's ,subjects2 ! said ,light ,h\se has be5 built2 & on ,fryday la/ ! #ad? ,currant ! ,light 0 k9dl$1 :i* w be v useful = all ,vessels go+ out & com+ 9 to ! ,h>b\r ( ,bo/on1 or any o!r ,h>b\rs 9 ! ,massa*usetts ,bay1 = :i* all ,ma/]s %all pay to ! ,receiv] ( ,impo/1 "o ,p5ny p] ,ton ,inw>ds1 & ano!r ,p5ny ,outw>ds1 except ,coa/]s1 :o are to pay ,two ,%ill+s ea*1 at _! cle>ance ,out1 ,& all ,fi%+ ,vessels1 ,wood ,sloops1 etc4 ,five ,%ill+s ea* by ! ,ye>4 ,?is 0 ! practical result ( a petition ( ,bo/on m]*ants made ?ree ye>s be=e4 ,! t[] 0 built ( /one1 at a co/ ( ab\t t5 ?\s& doll>s4 ,two ye>s lat] ! keep] & 8 family 7 dr[n$ & ! cata/rophe s affect$ ,b5jam9 ,frankl91 a boy ( ?irte51 t he wrote a poem conc]n+ x4 ,! ligh?\se 0 badly damag$ dur+ ! ,revolution1 by raid+-p>ties1 & 9 #aggf1 :5 ! ,briti% fleet left ! h>bor1 a squad ( sailors blew x up4 ,x 0 rebuilt 9 #aghc & has s9ce be5 increas$ 9 height4 ,app>5tly oil-lamps 7 us$ 9 x f ! beg9n+1 not)/&+ ! fact t c&les & coal fires s]v$ = ye>s 9 _m ligh?\ses ( ,europe4 ,9 #aghi sixte5 lamps 7 us$ & 9 #ahaa ,arg& lamps & reflectors 7 in/all$1 ) a revolv+ me*anism4 ,x n[ ceas$ to be a fix$ light & ! day ( fla%+ lights _h arriv$4 ,at ! pres5t "t ! ,bo/on ,light emits a beam ( #ajj1jjj c&le-p[] direct$ by mod]n l5ses4 ,:5 ! ,unit$ ,/ates ,gov]nm5t 0 organiz$ 9 #aghi !re 7 t5 ligh?\ses own$ by ! ,colonies1 b ! ,bo/on ,light 0 9 op]ation ?irty ye>s be=e ! o!rs4 ,s&y ,hook ,light1 ,new ,york ,h>bor1 0 e/abli%$ 9 #agfd & its orig9al masonry t[] is /ill /&+ & 9 use4 ,x is ! olde/ surviv+ ligh?\se 9 ?is c\ntry4 ,x 0 built ) funds rais$ by means ( two lott]ies au?oriz$ by ! ,new ,york ,assembly4 ,a few days aft] x 0 light$ = ! fir/ "t ! foll[+ news item appe>$ 9 a ,new ,york pap]3 ,on ,monday ev5+ la/ ! ,new ,york ,light-h\se erect$ at ,s&y ,hook 0 light$ = ! fir/ "t4 ,! ,h\se is ( an ,octagon ,figure1 hav+ eight equal ,sides2 ! ,diamet] at ! ,base #bi ,feet2 & at ! top ( ! ,wall1 #ae ,feet4 ,! ,lan?orn is #g feet high2 ! ,circumf]5ce #cc feet4 ,! :ole ,con/ruction ( ! ,lan?orn is ,iron2 ! ,top cov]$ ) ,copp]4 ,!re are #dh ,oil ,blazes4 ,! ,build+ f ! ,surface is ,n9e ,/ories2 ! :ole f ,bottom to ,top is #ajc ,feet4 ,f ^! e>ly ye>s ! numb] ( ligh?\ses has /eadily gr[n1 until n[ ! ,unit$ ,/ates ma9ta9s lights along #ej1jjj miles ( coa/-l9e & riv] *annels1 a di/ance equal to twice ! circumf]5ce ( ! e>?4 ,x ma9ta9s at ! pres5t "t ab\t #ae1jjj aids to navigation at an annual co/ ( ab\t #e1jjj1jjj4 ,9 #aiaf ?is c\ntry 0 op]at+ #agjf major lights1 #ec light-%ips1 & #eab light-buoys--a total ( #ecbc4 ,! e>lie/ ligh?\ses 7 equipp$ ) brazi]s or grates 9 :i* coal or wood 0 burn$4 ,^! crude light-s\rces 7 us$ until aft] ! adv5t ( ! n9ete5? c5tury & 9 "o case until #ahdf4 ,9 ! fam\s ,eddy/one t[] (f ,plym\?1 ,engl&1 c&les 7 us$ = ! fir/ "t4 ,! fir/ ,eddy/one t[] 0 complet$ 9 #afih1 b x 0 swept away 9 #agjc4 ,ano!r 0 built & de/roy$ by fire 9 #agee4 ,smeaton !n built ano!r 9 #agei4 ,inasmu* z ,smeaton is cr$it$ ) hav+ introduc$ ! use ( c&les1 ?is mu/ h occurr$ 9 ! eighte5? c5tury2 /ill x appe>s t1 z we h said1 ! ,bo/on ,light1 built 9 #agaf1 us$ oil-lamps f its beg9n+4 ,h[ev]1 ,smeaton in/all$ tw5ty-f\r c&les ( r l>ge size ea* cr$it$ ) an int5sity ( #b4h c&les4 ,! total lum9\s int5sity ( ! light-s\rce 9 ?is t[] 0 ab\t #fg c&les4 ,inasmu* z ?is 0 be=e ! use ( effici5t reflectors & l5ses1 x is obvi\s t ! e>ly ligh?\ses 7 r feeble beacons4 ,accord+ to ,briti% records1 oil-lamps ) flat wicks 7 fir/ us$ 9 ! ,liv]pool ligh?\ses 9 #agfc4 ,! ,arg& lamp1 introduc$ 9 ab\t #aghd1 became widely us$4 ,! bett] combu/ion obta9$ ) ?is lamp hav+ a cyl9drical wick & a glass *imney greatly increas$ ! lum9\s int5sity & g5]al satisfactor9ess ( ! oil-lamp4 ,lat] ,lange add$ an improvem5t by provid+ a contraction t[>d ! upp] "p ( ! *imney4 ,rum=d & also ,fresnel devis$ multiple-wick burn]s1 ?us increas+ ! lum9\s int5sity4 ,9 ^! e>ly lamps sp]m-oil & colza-oil 7 burn$ & !y cont9u$ to be until ! middle ( ! n9ete5? c5tury4 ,cocoanut-oil1 l>d-oil1 & olive-oil h also be5 us$ 9 ligh?\ses4 ,naturally1 m9]al oil 0 introduc$ z soon z x 0 available1 ow+ to its l[] co/2 b x 0 n until ne>ly #ahgj t a satisfactory m9]al-oil lamp 0 9 op]ation 9 ligh?\ses4 ,doty is cr$it$ ) ! inv5tion ( ! fir/ successful multiple-wick ligh?\se lamp us+ m9]al oil1 & 8 lamp & modifications ( x 7 v g5]ally us$ until ! latt] "p ( ! n9ete5? c5tury4 ,^! lamps are ( two types--"o 9 :i* oil is suppli$ to ! burn] "u pressure & ! o!r 9 :i* oil is ma9ta9$ at a con/ant level4 ,9 "s ( ! smalle/ lamps ! ord9>y capill>ity ( ! wick is dep5d$ on to supply oil to ! flame4 ,coal-gas 0 introduc$ into ligh?\ses 9 ab\t ! middle ( ! n9ete5? c5tury4 ,inasmu* z ! gas-mantle _h n yet appe>$1 ! gas 0 burn$ 9 jets4 ,v>i\s arrangem5ts ( ! jets1 su* z conc5tric r+s =m+ a /epp$ cone1 7 devis$4 ,! gas-mantle 0 a great boon to ! m>9] z well z to civiliz$ be+s 9 g5]al4 ,x greatly increases ! int5sity ( light obta9able f a giv5 am\nt ( fuel & x is a fairly compact bright s\rce :i* makes x possible to direct ! light to "s degree by means ( optical sy/ems4 ,ow+ to ! elaborate app>atus necess>y = mak+ coal-gas1 sev]al o!r gases h be5 m desirable fuels = ligh?\se lamps4 ,v>i\s simple gas-g5]ators h be5 devis$4 ,"s ( ! high-fla% m9]al-oils are vaporiz$ & burn$ "u a mantle4 ,acetyl5e1 :i* is s simply made by means ( calcium c>bide & wat]1 has be5 a great factor 9 light+ = navigation4 ,by ! latt] "p ( ! n9ete5? c5tury ligh?\ses employ+ inc&esc5t gas-burn]s 7 emitt+ beams ( light hav+ lum9\s int5sities z great z sev]al hundr$ ?\s& c&les4 ,^! special gas-mantle light-s\rces h brightness z high z sev]al hundr$ c&les p] squ>e in*4 ,electric arc-lamps 7 fir/ introduc$ into ligh?\se s]vice 9 ab\t #ahfj1 b ^! lamps _c be consid]$ to h be5 really practicable until ab\t #ahge4 ,9 #ahhc ! ,briti% ligh?\se au?orities c>ri$ out an ext5sive inve/igation ( arc-lamps4 ,x 0 f\nd t ! :it] light f ^! lamps suff]$ a great] absorption by ! atmosph]e ?an ! yell[] light f oils1 b ! mu* great] lum9\s int5sity ( ! arc-lamp m ?an comp5sat$ = ?is disadvantage4 ,! f9al result ( ! inve/igation 0 ! conclusion t = ord9>y ligh?\se purposes ! oil-& gas-lamps 7 m suitable & economical ?an arc-lamps2 b :]e great range 0 desir$1 ! latt] 7 mu* m advantage\s1 ow+ to _! great lum9\s int5sity4 ,electric inc&esc5t filam5t lamps h be5 us$ = ! less important lights1 & rec5tly !re has be5 "s application ( ! mod]n high-effici5cy filam5t lamps4 ,besides ! high t[]s !re are _m m9or beacons1 light-%ips1 & light-buoys 9 use4 ,_m ( ^! are unt5d$ & !re=e mu/ op]ate automatically4 ,! light-%ip is us$ :]e x is impracticable or too exp5sive to build a ligh?\se4 ,inasmu* z x is an*or$ 9 fairly deep wat]1 x is safe 9 foggy wea!r to /e] almo/ directly t[>d its position z indicat$ by ! fog-signal4 ,light-%ips are m exp5sive to ma9ta9 ?an ligh?\ses1 b !y h ! advantages ( small] co/ & ( mobility2 = sometimes x may be desir$ to move !m4 ,! fir/ light-%ip 0 e/abli%$ 9 #agcb ne> ! m\? ( ! ,?ames1 & ! fir/ 9 ?is c\ntry 0 an*or$ 9 ,*esapeake ,bay ne> ,norfolk 9 #ahbj4 ,! e>ly %ips _h no mode ( self-propulsion1 b ! mod]n ones are be+ provid$ ) _! own p[]4 ,oil & gas h be5 us$ z fuel = ! light-s\rces & 9 #ahib ! ,u4 ,s4 ,ligh?\se ,bo>d con/ruct$ a light-%ip ) a p[]ful electric light4 ,s9ce t "t sev]al h be5 equipp$ ) electric lights suppli$ by electric g5]ators & batt]ies4 ,unt5d$ lights 7 n develop$ until ab\t #ahhj1 :5 ,p9ts* introduc$ 8 weld$ buoys fill$ ) compress$ gas & !reby provid$ a complete light+-plant4 ,) improvem5ts 9 lamps & controls ! unt5d$ light-buoys became a success4 ,! lights burn = sev]al mon?s1 & ev5 = a ye> cont9u\sly2 & ! oil-gas us$ appe>s to be v satisfactory4 ,rec5tly "s exp]im5ts h be5 made ) devices :i* w\ld be actuat$ by sunlight 9 su* a mann] t ! light w\ld be ext+ui%$ dur+ ! day except+ a small pilot-flame4 ,by ?is means a long] p]iod ( burn+ )\t att5tion may be obta9$4 ,electric filam5t lamps suppli$ by batt]ies or by cables f ! %ore h be5 us$1 b ! oil-gas buoy /ill rema9s 9 favor4 ,acetyl5e has be5 employ$ z a fuel = light-buoys4 ,automatic g5]ators h be5 devis$1 b ! high-pressure sy/em is m simple4 ,9 ! latt] case purifi$ acetyl5e is held 9 solution "u high pressure 9 a res]voir conta9+ an asbe/os composition saturat$ ) acetone4 ,! light-s\rces ( beacons h _h ! same hi/ory z ^? ( o!r navigation lights4 ,_m ( ^! are automatic 9 op]ation1 sometimes be+ controll$ by clockwork4 ,dur+ ! la/ tw5ty ye>s ! gas-mantle has be5 v g5]ally appli$ to beacon-lights4 ,9 ! latt] "p ( ! n9ete5? c5tury a m9]al-oil lamp 0 devis$ ) a p]man5t wick made by =m+ ^u a ?ick wick a coat+ ( c>bon4 ,! op]ation is su* t ?is is n consum$ & x prev5ts fur!r burn+ ( ! wick4 ,! optical app>atus ( navigation lights has und]gone _m improvem5ts 9 ! pa/ c5tury4 ,! e>ly lights 7 n equipp$ ) ei!r reflect+ or refract+ app>atus4 ,9 #ahbd ,drummond devis$ a s*eme = reflect+ light 9 ord] t a di/ant obs]v] might make a read+ ^u ! po9t :]e ! app>atus 0 be+ op]at$ by ano!r p]son4 ,he 0 l$ by 8 exp]im5ts to sugge/ ! application ( mirrors to ligh?\ses4 ,8 device 0 ess5tially a p>abolic mirror simil> to ! reflectors n[ widely us$ 9 automobile head-lamps1 se>*-lights1 etc4 ,he employ$ ! lime-light z a s\rce ( light & 0 en?usia/ic ov] ! results obta9$4 ,8 discussion publi%$ 9 #ahbf indicates t little practical "w _h be5 done up to t "t t[>d obta9+ beams or belts ( light by means ( optical app>atus4 ,h[ev]1 ligh?\se records %[ t z e>ly z #agfc small silv]$ plane glasses 7 set 9 pla/] ( ,p>is 9 su* a mann] z to =m a p>tially envelop+ reflector4 ,sph]ical reflectors 7 introduc$ 9 ab\t #aghj & p>abolic reflectors ab\t t5 ye>s lat]4 ,all ! e>li] lights 7 fix$1 b z x is desirable t ! m>9] be able to di/+ui% "o light f ano!r1 ! revolv+ me*anism evolv$4 ,by its ag5cy *>act]i/ic fla%es are obta9$ & f ! "t int]val ! light is recogniz$4 ,! fir/ revolv+ me*anism 0 in/all$ 9 #aghc4 ,! e>ly fla%+ lights 7 obta9$ by means ( revolv+ reflectors :i* ga!r$ ! light & direct$ x 9 ! =m ( a beam or p5cil4 ,! type ( p>abolic reflector n[ 9 use does n diff] ess5tially f t ( an automobile head-lamp1 except+ t x is l>g]4 ,l5ses appe> to h be5 introduc$ 9 ! latt] "p ( ! n9ete5? c5tury4 ,!y 7 at fir/ gr\nd f a solid piece ( glass1 9 conc5tric zones1 9 ord] to r$uce ! ?ickness4 ,!y 7 simil> 9 pr9ciple to "s ( ! tail-light l5ses us$ at pres5t on automobiles4 ,lat] ! l5ses 7 built up by means ( sep>ate annul> r+s4 ,! "n ( ,fresnel is p]man5tly associat$ ) ligh?\se l5ses because 9 #ahbb he develop$ an elaborate built-up l5s ( annul> r+s4 ,! c5t]s ( curvature ( ! diff]5t r+s rec$$ f ! axis z _! di/ance f ! c5t] increas$1 9 su* a mann] z to ov]come a s]i\s optical defect kn[n z sph]ical ab]ration4 ,fresnel devis$ _m improvem5ts 9 :i* he us$ refract+ & reflect+ prisms = ! out] elem5ts4 ,! optical app>atus ( ligh?\ses usually aims 7#a7 to conc5trate ! rays ( light into a p5cil ( light1 7#b7 to conc5trate !m into a belt ( light1 or 7#c7 to conc5trate ! rays ov] a limit$ azimu?4 ,9 ! fir/ case a s+le l5s or a p>abolic reflector suffices1 b 9 ! second case a cyl9drical l5s :i* cond5ses ! light v]tically into a horizontal %eet ( light is ess5tial4 ,! ?ird case is a comb9ation ( ! fir/ two4 ,! mod]n ligh?\se l5ses are v elaborate 9 con/ruction1 be+ built up by means ( _m elem5ts into sev]al sections4 ,= example1 ! c5tral section may consi/ ( a sph]ical l5s gr\nd ) annul> r+s4 ,9 ! next section refract+ prisms may be us$ & 9 ! out] section reflect+ glass prisms are employ$4 ,! v>i\s elem5ts are c>efully design$ accord+ to ! laws ( geometrical optics4 ,! fla%+ light has su* advantages ov] ! fix$ t x is g5]ally us$ = important beacons4 ,a v>iety ( me?ods ( obta9+ int]mitt5t light h be5 employ$1 b !y are n ( p>ticul> int]e/4 ,sometimes ! l5s or reflector is revolv$ & 9 o!r types an opaque scre5 conta9+ slits is revolv$4 ,9 ! l>g] ligh?\ses ! optical app>atus & its /ructure sometimes weigh sev]al tons4 ,:5 x is necess>y to revolve app>atus ( ?is weight1 ! :ole me*anism is float$ ^u m]cury conta9$ 9 a ca/-iron vessel ( suitable size1 & by an +5i\s arrangem5t only a small portion ( m]cury is requir$4 ,! *>act]i/ics ( navigation lights are v>i$ consid]ably 9 ord] to enable ! m>9] to di/+ui% !m & !reby to le>n exactly :]e he is4 ,! fix$ light is liable to be confus$ ) o!rs1 s x has n[ become a m9or light4 ,fla%es ( %ort duration foll[$ by long] p]iods ( d>kness are ext5sively us$4 ,! m>9] by tim+ ! int]vals is able to recognize ! light4 ,?is me?od is ext5d$ to gr\ps ( %ort fla%es foll[$ by long] int]vals ( d>kness4 ,9 fact1 %ort fla%es h be5 employ$ to indicate a c]ta9 numb] s t a m>9] c\ld recognize ! light by a numb] r ?an by means ( 8 wat*4 ,h[ev]1 a "t elem5t is g5]ally us$4 ,a comb9ation ( fix$ light ^u :i* is sup]pos$ a fla% or a gr\p ( fla%es ( :ite or ( color$ light has be5 us$1 b x is 9 disrepute z be+ unreliable4 ,a type kn[n z occulat+ lights consi/s ( a fix$ light :i* is mom5t>ily eclips$1 b ! duration ( ! eclipse is usually less ?an t ( ! light4 ,obvi\sly1 gr\ps ( eclipses may be us$4 ,sometimes lights ( diff]5t colors are alt]nat$ )\t any d>k int]vals4 ,! color$ ones us$ are g5]ally r$ & gre51 b ^! are %ort-range lights at be/4 ,color$ sectors are sometimes us$ ov] portions ( ! field1 9 ord] to indicate dang]s1 & :ite light %[s 9 ! fairway4 ,^! are usually fix$ lights = m>k+ ! *annel4 ,! di/ance at :i* a light may be se5 at sea dep5ds ^u its lum9\s int5sity1 ^u its color or spectral composition1 ^u its height & t ( ! obs]v]'s eyes above ! sea-level1 & ^u ! atmosph]ic conditions4 ,assum+ a p]fectly cle> atmosph]e1 ! visibility ( a light-s\rce app>5tly dep5ds directly ^u its c&le-p[]4 ,! atmosph]e ord9>ily absorbs ! r$1 orange1 & yell[ rays less ?an ! gre51 blue1 & violet rays4 ,?is is demon/rat$ by ! sett+ sun1 :i* z x approa*es clos] to ! horizon *anges f yell[ to orange & f9ally to r$ z ! am\nt ( atmosph]e betwe5 x & ! eye increases4 ,= ?is reason a r$ light w\ld h a great] range ?an a blue light ( ! same lum9\s int5sity4 ,"u ord9>y atmosph]ic conditions ! range ( ! m p[]ful light-s\rces us$ 9 ligh?\ses is great] ?an ! range z limit$ by ! curvature ( ! e>?4 ,= ! uncolor$ illum9ants ! range 9 nautical miles appe>s to be at lea/ equal to ! squ>e root ( ! c&le-p[]4 ,a real practical limitation :i* /ill exi/s is ! curvature ( ! e>?1 & ! di/ance an object may be se5 by ! eye at sea-level dep5ds ^u ! height ( ! object4 ,! relation is approximately express$ ?us1-- ,range 9 nautical miles #h_/g squ>e root ( ,height ( object 9 feet4 ,= example1 ! top ( a t[] #ajj feet high is visible to an eye at sea-level a di/ance ( #h_/g squ>e root ( #ajj #hj_/g #aa4dc miles4 ,n[ if ! eye is #di feet above sea-level1 a simil> computation w %[ h[ f> away x may be se5 by ! orig9al eye at sea-level4 ,?is is #h_/g squ>e root ( #di #h miles4 ,h5ce an eye #di feet above sea-level w be able to see ! top ( ! #ajj-;foot t[] at a di/ance ( #aa4dc #h or #ai4dc nautical miles4 ,"u ^! conditions an imag9>y l9e drawn f ! top ( ! t[] to ! eye w be j tang5t to ! sph]ical surface ( ! sea at a di/ance ( #h miles f ! eye & #aa4dc miles f ! t[]4 ,! lum9\s int5sity ( a light-s\rce or ( ! beam ( light is directly responsible = ! range4 ,! lum9\s int5sity ( ! e>ly beacon-fires & oil-lamps 0 equival5t to a few c&les4 ,! improvem5ts 9 light-s\rces & also 9 reflect+ & refract+ optical sy/ems h /eadily increas$ ! c&le-p[] ( ! beams1 until to-day ! beams f gas-lamps h int5sities z high z sev]al hundr$ ?\s& c&le-p[]4 ,! beams s5t =? by mod]n ligh?\ses equipp$ ) electric lamps & enorm\s light-ga!r+ devices are rat$ 9 millions ( c&le-p[]4 ,9 fact1 ,naves9k ,light at ! entrance ( ,new ,york ,bay is rat$ z high z #fj1jjj1jjj c&le-p[]4 ,( c\rse1 light-production has increas$ enorm\sly 9 effici5cy 9 ! pa/ c5tury1 b )\t optical devices = ga!r+ ! light1 ! enorm\s beam int5sity w\ld n be obta9$4 ,= example1 consid] a small s\rce ( light possess+ a lum9\s int5sity ( "o c&le 9 all directions4 ,if all ?is light :i* is emitt$ 9 all directions is ga!r$ & s5t =? 9 a beam ( small angle1 say "o ?\s&? ( ! total angle surr\nd+ a po9t1 ! int5sity ( ?is beam w\ld be #ajjj c&les4 ,x is 9 ?is mann] t ! enorm\s beam int5sities are built up4 ,!re is an int]e/+ po9t p]ta9+ to %ort fla%es ( light4 ,to ! d>k-adapt$ eye a brief fla% is regi/]$ z ( consid]ably high] int5sity ?an if ! light rema9$ con/ant4 ,9 o!r words1 ! look\t on a vessel is adapt$ to d>kness & a fla% f a beam ( light is mu* bright] ?an if ! same beam 7 %9+ /eadily4 ,?is is a physiological ph5om5on :i* op]ates 9 favor ( ! fla%+ light4 ,illu/ration3 ,a4 ,a ,,complet$ ,,ligh?\se ,,l5s ,illu/ration3 ,b4 ,,torro ,,po9t ,,ligh?\se1 ,,panama ,,canal ,illu/ration3 ,,am]ican ,,se>*-,,light ,,position ,,on ,,we/]n ,,front ,,9 #aiai ,illu/ration3 ,,am]ican ,,/&>d ,,field ,,se>*-,,light ,,& ,,p[] ,,unit ,d\btless1 ! read] has not$ t reliability1 simplicity1 & l[ co/ ( op]ation are ! prim>y consid]ations = light-s\rces us$ z aids to navigation4 ,?is acc\nts = ! cont9u$ use ( oil & gas4 ,f an optical /&po9t ! electric arc-lamps & conc5trat$-filam5t lamps are usually sup]ior to ! e>li] s\rces ( light1 b ! complexity ( a plant = g5]at+ electricity is usually a disadvantage 9 isolat$ places4 ,! l>g] light-%ips are n[ us+ electricity g5]at$ by app>atus in/all$ 9 ! vessels4 ,!re seems to be a t5d5cy t[>d ! use ( m buoys & few] ligh?\ses1 b ! beam-int5sities ( ! latt] are increas+4 ,9 ! hundr$ ye>s s9ce ! ,bo/on ,light 0 built ! same great *anges wr\ght by ! developm5t ( artificial light 9 o!r activities ( civilization h appe>$ 9 ! beacons ( ! m>9]4 ,! developm5t ( ^! aids to navigation has be5 wond]ful1 b x mu/ g on & on4 ,! surface ( ! e>? comprises #ea1hhf1jjj squ>e /atute miles ( l& & #ade1jed1jjj squ>e miles ( wat]4 ,?ree f\r?s ( ! e>?'s surface is wat] & ! oceans w always be highways ( _w comm]ce4 ,all ! dang]s _c be ov]come1 b human +5uity is capable ( great a*ievem5ts4 ,wreckage w appe> along ! %ore-l9es despite ! lights1 b ! h>ve/ ( ! %oals has be5 mu* r$uc$ s9ce ! "t describ$ by ,rob]t ,l\is ,/ev5son1 :5 ! coa/ p 9 ! ,orkneys look$ ^u wrecks z a s\rce ( ga94 ,he /ates3 ,x _h become prov]bial ) "s ( ! inhabitants to obs]ve t if wrecks 7 to happ51 !y might z well be s5t to ! poor isl& ( ,s&ay z any:]e else4 ,on ?is & ! neighbor+ isl&1 ! inhabitants h c]ta9ly _h _! %>e ( wreck$ goods4 ,on compla9+ to "o ( ! pilots ( ! badness ( 8 boat's sails1 he repli$ ) "s degree ( pleasantry1 ,_h x be5 ,8 ,god's w t y come na "h wi ^! lights1 we might a' _h bett] sails to our boats & m o' o!r ?+s4 ,9 ! leas+ ( f>ms1 a location ) a great] probability ( %ipwreck on ! %ore br\ght a mu* high] r5t4 ,,xiv ,,artificial ,,light ,,9 ,,w>f>e ,:5 ! rec5t w> broke out sci5ce respond$ to ! call & "u ! /ress ( fev]i% necessity compress$ ! normal developm5t ( a half-c5tury into a few ye>s4 ,! airplane1 9 #aiad a d\btful play?+ ( d>$evils1 em]g$ f ! w> a p]fect$ ?+ ( ! air4 ,light+ did n h ! glamor ( fly+ or ! novelty ( *emical w>f>e1 b x progress$ greatly 9 c]ta9 directions & s]v$ well4 ,:ile artificial light+ conduct$ its unh]ald$ (f5sive by increas+ production 9 ! support+ indu/ries & help$ to ma9ta9 liaison ) ! front-l9e tr5*es by l5d+ eyes to transportation1 x 0 also do+ its "p at ! battle front4 ,huge se>*-lights reveal$ ! subm>9e & ! arial bomb]2 fl>es expos$ ! manoeuv]s ( ! enemy2 rockets br\ght aid to beleagu]$ vessels & troops2 pi/ol lights fir$ by ! arial obs]v] direct$ artill]y fire2 & _m o!r devices ( artificial light 7 9 ! fray4 ,_m improvem5ts 7 made 9 se>*-lights & 9 signal+ devices & ! elem5ts ( ! fe/ive fireworks ( pa/ ages 7 improv$ & develop$ = ! ne$s ( mod]n w>f>e4 ,night aft] night along ! battle front fl>es 7 s5t up to reveal patrols & any o!r enemy activity4 ,on ! slighte/ suspicion great sw>ms ( ^! brilliant lights w\ld bur/ =? z ?\gh flocks ( huge fireflies _h be5 di/urb$4 ,!y 7 ev5 us$ z light b>rages1 = movem5ts c\ld be execut$ 9 comp>ative safety :5 a l>ge numb] ( ^! lights lay be=e ! enemy's tr5*es sputt]+ _! brilliant light4 ,! airman dropp$ fl>es to illum9ate 8 t>get or 8 l&+ field4 ,! tor*es ( pa/ p>ades aid$ ! soldi] 9 8 night op]ations & rockets s5t skyw>d radiat$ _! messages to headqu>t]s 9 ! re>4 ,! />-%ell _h ! same missions z o!r fl>es1 b x 0 project$ by a *>ge ( p[d] f a gun4 ,^! & _m modifications repres5t ! useful applications ( :at =m]ly 7 m]e fireworks4 ,^? :i* are prim>ily signal+ devices are discuss$ 9 ano!r *apt]1 b ! o!rs w be describ$ suffici5tly to indicate ! place :i* artificial light play$ 9 c]ta9 phases ( w>f>e4 ,! illum9at+ comp\nds us$ 9 ^! devices are n p>ticul>ly new1 consi/+ ess5tially ( a combu/ible p[d] & *emical salts :i* make ! flame lum9\s & give x color :5 desir$4 ,among ! +r$i5ts are b>ium nitrate1 potassium p]*lorate1 p[d]$ alum9um1 p[d]$ magnesium1 potassium nitrate1 & sulphur4 ,"o ( ! simple/ mixtures us$ by ! ,engli% is1 ,b>ium nitrate #cg p] c5t4 ,p[d]$ magnesium #cd p] c5t4 ,potassium nitrate #bi p] c5t4 ,! magnesium is coat$ ) hot wax or p>aff91 :i* n only acts z a b9d] = ! mixture :5 x is press$ into its conta9] b also s]ves to prev5t oxidation ( ! magnesium :5 ! %ells are /or$4 ,! b>ium & potassium nitrates supply ! oxyg5 to ! magnesium1 :i* burns ) a brilliant :ite flame4 ,! potassium nitrate takes fire m readily ?an ! b>ium nitrate1 b x is m exp5sive ?an ! latt]4 ,ow+ to ! co/ ( magnesium1 p[d]$ alum9um has be5 us$ to "s ext5t z a sub/itute4 ,alum9um does n h ! illum9at+ value ( magnesium & x is m difficult to ignite1 b x is a good sub/itute 9 case ( necessity4 ,an ,engli% mixture conta9+ ^! elem5ts is1 ,b>ium nitrate #eh p] c5t4 ,magnesium #bi p] c5t4 ,alum9um #ac p] c5t4 ,mixtures :i* are sl[ to ignite mu/ be supplem5t$ by a prim>y mixture :i* is readily ignit$4 ,= obta9+ color$ lights x is only necess>y to add *emicals :i* w give ! desir$ color4 ,! mixtures c be proportion$ by means ( purely !oretical consid]ations2 t is1 j en\gh oxyg5 c be pres5t to burn ! fuel completely4 ,h[ev]1 usually m oxyg5 is suppli$ ?an call$ = by !ory4 ,! illum9at+ %ell is p]haps ! mo/ useful ( ^! devices to ! soldi]4 ,x has be5 con/ruct$ ) & )\t p>a*utes1 ! =m] provid+ an int5se light = a brief p]iod because x falls rapidly4 ,^! %ells ( ! l>g] calib]s are equipp$ ) "t-fuses & are g5]ally r elaborate 9 con/ruction4 ,! %ell is ( /eel1 & has a "t-fuse at ! tip4 ,?is fuse ignites a *>ge ( black p[d] 9 ! nose ( ! %ell & ?is explosion ejects ! />-%ell out ( ! re> ( ! /eel cas+4 ,at ! same "t ! black p[d] ignites ! prim+ mixture next to x1 :i* 9 turn ignites ! sl[-burn+ illum9at+ comp\nd4 ,! />-%ell has a l>ge p>a*ute ( /rong mat]ial fold$ 9 ! re> ( ! cas+ & ! c>dbo>d tube conta9+ ! illum9at+ mixture is atta*$ to x4 ,! "t ( burn+ v>ies1 b is ord9>ily less ?an a m9ute4 ,c]ta9 /ructural details mu/ be su* z to endure ! /resses ( a high muzzle velocity4 ,fur!rmore1 a velocity ( p]haps #ajjj feet p] second /ill obta9s :5 ! />-%ell ) its p>a*ute is eject$ at ! desir$ po9t 9 ! air4 ,! non-p>a*ute illum9at+ %ell is design$ to give an int5se light = a brief int]val & is especially applicable to def5se aga9/ air raids4 ,su* a light aims to reveal ! aircraft 9 ord] t ! gunn]s may fire at x effectively4 ,^! %ells are fitt$ ) "t-fuses :i* fire ! *>ge ( black p[d] at ! desir$ int]val aft] ! dis*>ge ( ! %ell f ! gun4 ,! cont5ts ( ! %ell are !reby eject$ & ignit$4 ,! conta9] = ! illum9at+ mat]ial is s design$ t !re is rapid combu/ion & consequ5tly a brilliant light = ab\t t5 seconds4 ,! enemy airman 9 ?is %ort "t is unable to obta9 any valuable k p]ta9+ to ! e>? bel[ & fur!rmore he is likely to be tempor>ily bl9d$ by ! brilliant light if x is ne> him4 ,! rifle-light :i* resembles an ord9>y rocket1 is fir$ f a rifle & is design$ = %ort-range use4 ,x consi/s ( a /eel cyl9drical %ell a few in*es long fa/5$ to a /eel rod4 ,a p>a*ute is atta*$ to ! c>dbo>d conta9] 9 :i* ! illum9at+ mixture is pack$ & ! :ole is /[$ away 9 ! /eel %ell4 ,%ore delay-fuses are us$ = />t+ ! usual cycle ( ev5ts aft] ! rifle-light has be5 fir$ f ! gun4 ,! /eel rod is inject$ into ! b>rel ( a rifle & a blank c>tridge is us$ = eject+ ?is rocket-l app>atus4 ,ow+ to in]tia ! fir+-p9 9 ! %ell op]ates & ! %ort delay-fuse is ?us fir$ automatically an in/ant aft] ! trigg] ( ! rifle is pull$4 ,illum9at+ bombs ( ! same g5]al pr9ciples are us$ by airm5 9 se>* ( a l&+ = himself or = a de/ructive bomb2 9 signal+ to a gunn]1 & 9 _m o!r ways4 ,!y are simple 9 con/ruction because !y ne$ n )/& ! /resses ( be+ fir$ f a gun2 !y are m]ely dropp$ f ! aircraft4 ,! me*anism ( ignition & ! cycle ( ev5ts :i* foll[ are simil> to ^? ( o!r illum9at+ %ells4 ,! value ( su* artificial-light+ devices dep5ds bo? ^u lum9\s int5sity & "t ( burn+4 ,al?\gh long-burn+ is n g5]ally requir$ 9 w>f>e1 x is obvi\s t m ?an a mom5t>y light is usually ne$$4 ,9 g5]al1 high c&le-p[] & long-burn+ are oppos$ to ea* o!r1 s t ! mo/ int5se lights ( ?is "* usually are ( %ort duration4 ,typical p]=mances ( two fl>es ( ! same composition are z foll[s3 ,fl>e ,no4 #a ,fl>e ,no4 #b ,av]age c&le-p[] #bgj1jjj #ie1jjj ,seconds ( burn+ #aj #ce ,c&le-seconds #b1gjj1jjj #c1cbe1jjj ,cubic in*es ( comp\nd #f #g ,c&le-seconds p] cubic in* #dej1jjj #dge1jjj ,c&le-h\rs p] cubic in* #abe #acb ,! illum9at+ comp\nd 0 ! same 9 ^! two fl>es1 :i* diff]$ only 9 ! "t all[$ = burn+4 ,( c\rse1 ! measurem5ts ( ! lum9\s int5sity ( su* fl>es is difficult because ( ! fluctuations1 b )9 ! errors ( ! measurem5ts x is se5 t ! illum9at+ p[] ( ! comp\nd is ab\t ! same reg>dless ( ! "t ( burn+4 ,! light-s\rce 9 ! case ( burn+ p[d]s is really a flame1 & inasmu* z ! burn+ end hangs d[nw>d1 m light is emitt$ 9 ! l[] hemisph]e ?an 9 ! upp]4 ,! c&le-p[] ( ! l>ge/ fl>es equals ! comb9$ lum9\s int5sities ( #bjj /reet arc-lamps or ( #aj1jjj ord9>y #dj-watt tung/5 lamps su* z are us$ 9 resid5ce light+4 ,x is int]e/+ to note ! c&le-h\rs obta9$ p] cubic in* ( comp\nd & to f9d t ! co/ ( ?is light is less ?an t ( c&les at ! pres5t "t & only five or t5 times great] ?an t ( mod]n electric light+4 ,illum9at+ %ells 9 use dur+ ! rec5t w> 7 design$ = muzzle velocities z high z #bgjj feet p] second & 7 gag$ to ignite at any di/ance f a qu>t] ( a mile to sev]al miles4 ,! maximum range ( illum9at+ %ells fir$ f rifles 0 ab\t #bjj y>ds2 = tr5* mort>s ab\t "o mile2 & f field & naval guns ab\t f\r miles4 ,! se>*-light has long be5 a valuable aid 9 w>f>e & dur+ ! rec5t conflict consid]able att5tion 0 giv5 to its developm5t & application4 ,x is us$ *iefly = detect+ & illum9at+ di/ant t>gets1 b ?is cov]s a wide range ( conditions & requirem5ts4 ,9 ord] t a se>*-light may be effective at a great di/ance1 z mu* z possible ( ! light emitt$ by a s\rce is direct$ into a beam ( light ( z ne>ly p>allel rays z c be obta9$4 ,reflectors are usually employ$ 9 milit>y se>*-lights1 & 9 ord] t ! beam may be z ne>ly p>allel 7m9imum div]g5ce7 z possible1 ! light mu/ be emitt$ by ! smalle/ s\rce compatible ) high int5sity4 ,?is s\rce is plac$ at ! prop] po9t 9 respect to a l>ge p>abolic reflect] :i* r5d]s ! rays p>allel or ne>ly s4 ,ev] s9ce its adv5t ! electric arc has be5 employ$ 9 l>ge se>*-lights1 ) :i* ! army & ! navy 7 suppli$2 h[ev]1 ! greate/ improvem5ts h be5 made "u ! /ress ( w>4 ,! sci5ce ( aronautics advanc$ s rapidly dur+ ! rec5t w> t ! necessity = p[]ful se>*-lights 0 greatly augm5t$ & z ! conflict progress$ ! enemy airm5 came to look ^u ! newly develop$ ones ) consid]able conc]n4 ,! rapidly mov+ aircraft & its high altitude br\ght new factors into ! design ( ^! lights4 ,x n[ became necess>y to h ! mo/ int5se beam & to be able to sweep ! heav5s ) x by means ( delicate controll+ app>atus1 = ! t>gets 7 sometimes m9ute specks mov+ at high spe$ at altitudes z high z five miles4 ,fur!rmore1 ow+ to ! %ift+ battle areas1 mobile app>atus 0 necess>y4 ,! control ( light by means ( reflectors has be5 /udi$ = c5turies1 b until ! adv5t ( ! electric arc ! light-s\rces 7 ( su* l>ge areas t effective control 0 impossible4 ,optical devices g5]ally are consid]$ 9 connection ) po9t s\rces1 b inasmu* z no light c be obta9$ f a po9t1 a s\rce ( small dim5sions & ( high brightness is ! mo/ effective compromise4 ,p>abolic mirrors 7 9 use 9 ! eighte5? c5tury & _! prop]ties 7 kn[n long be=e ! fir/ se>*-light wor?y ( ! "n 0 made 9 #ahbe by ,drummond1 :o us$ z a s\rce ( light a piece ( lime heat$ to inc&esc5ce 9 a bla/ flame4 ,he f9ally develop$ ! lime-light by direct+ an oxyhydrog5 flame ^u a piece ( lime & ?is device 0 adapt$ to se>*-lights & to indoor projection4 ,x is said t ! fir/ se>*-light to be us$ 9 w>f>e 0 a ,drummond lime-light :i* play$ a "p 9 ! attack on ,=t ,wagn] at ,*>le/on 9 #ahfc4 ,9 #ahdh ! fir/ electric arc lamp us$ = g5]al light+ 0 in/all$ 9 ,p>is4 ,x 0 suppli$ ) curr5t by a l>ge voltaic cell1 b ! success ( ! electric arc 0 oblig$ to await ! developm5t ( a m satisfactory s\rce ( electricity4 ,a score ( ye>s 0 de/9$ to elapse1 aft] ! public 0 amaz$ by ! fir/ demon/ration1 be=e a suitable electric dynamo 0 inv5t$4 ,) ! adv5t ( ! dynamo1 ! electric arc 0 rapidly develop$ & ?us !re became available a conc5trat$ light-s\rce ( high int5sity & great brilliancy4 ,gradually ! size 0 increas$1 until at ! pres5t "t mirrors z l>ge z sev5 feet 9 diamet] & electric curr5ts z great z sev]al hundr$ amp]es are employ$4 ,! beam int5sities ( ! mo/ p[]ful se>*-lights are n[ z great z sev]al hundr$ million c&les4 ,! mo/ notable advance 9 ! design ( arc se>*-lights 0 a*iev$ 9 rec5t ye>s by ,beck1 :o develop$ an int5sive flame c>bon-arc4 ,8 *ief object 0 to s5d a mu* great] curr5t ?r\gh ! arc ?an _h be5 done previ\sly )\t increas+ ! size ( ! c>bons & ! un/ead9ess ( ! arc4 ,9 ! ord9>y arc excessive curr5t causes ! c>bons to dis9tegrate rapidly unless !y are ( l>ge diamet]4 ,beck direct$ a /ream ( alcohol vapor at ! arc & !y 7 kept f oxidiz+4 ,he ?us a*iev$ a high curr5t-d5sity & mu* great] beam int5sities4 ,he also us$ cor$ c>bons conta9+ c]ta9 metallic salts :i* add$ to ! lum9\s int5sity1 & by rotation ( ! positive c>bon s t ! crat] 0 kept 9 a con/ant position1 great] /ead9ess & uni=mity 7 obta9$4 ,te/s %[ t1 9 addition to its high] lum9\s effici5cy1 an arc ( ?is "* directs a great] p]c5tage ( ! light into ! effective angle ( ! mirror4 ,! small s\rce results 9 a beam ( small div]g5ce2 9 o!r words1 ! beam diff]s f a cyl9d] by only "o or two degrees4 ,if ! beam consi/$ entirely ( p>allel rays & if !re 7 no loss ( light 9 ! atmosph]e by scatt]+ or by absorption1 ! beam int5sity w\ld be ! same ?r\gh\t its entire l5g?4 ,h[ev]1 bo? div]g5ce & atmosph]ic losses t5d to r$uce ! int5sity ( ! beam z ! di/ance f ! se>*-light increases4 ,inasmu* z ! int5sity ( ! beam dep5ds ^u ! actual brightness ( ! light-s\rce1 ! brightness ( a few mod]n light-s\rces are ( int]e/4 ,^! are express$ 9 c&les p] squ>e in* ( project$ area2 t is1 if a small hole 9 a %eet ( metal is plac$ next to ! light-s\rce & ! int5sity ( ! light pass+ ?r\gh ?is hole is measur$1 ! brightness ( ! hole is easily det]m9$ 9 c&les p] squ>e in*4 ,,brightness ,,( ,,light-,,s\rces ,,9 ,,c&les ,,p] ,,squ>e ,,in* ,k]os5e flame #e to #aj ,acetyl5e #cj to #fj ,gas-mantle #cj to #ejj ,tung/5 filam5t 7vacuum7 lamp #gej to #a1bjj ,tung/5 filam5t 7gas-fill$7 lamp #c1ejj to #ah1jjj ,magnetite arc #d1jjj to #f1jjj ,c>bon arc = se>*-lights #hj1jjj to #ij1jjj ,flame arc = se>*-lights #bej1jjj to #cej1jjj ,sun 7comput$ mean7 ab\t #a1jjj1jjj ,z ! reflector ( a se>*-light is an exce$+ly important factor 9 obta9+ high beam-int5sities1 consid]able att5tion has be5 giv5 to x s9ce ! practicable electric arc appe>$4 ,! p>abolic mirror has ! prop]ty ( r5d]+ p>allel1 or ne>ly s1 ! rays f a light-s\rce plac$ at its focus4 ,if ! mirror subt5ds a l>ge angle at ! light-s\rce1 a great] am\nt ( light is int]cept$ & r5d]$ p>allel ?an 9 ! case ( small] subt5d$ angles2 h5ce1 mirrors are l>ge & ( z %ort focus z practicable4 ,se>*-light projectors direct f #cj to #fj p] c5t4 ( ! available light into ! beam1 b ) l5s sy/ems ! effective angle is s small t a mu* small] p]c5tage is deliv]$ 9 ! beam4 ,mang9 9 #ahgd made a reflector ( glass 9 :i* bo? out] & inn] surfaces 7 sph]ical b ( diff]5t radii ( curvature1 s t ! reflector 0 ?ick] 9 ! middle4 ,?is device 0 silv]$ on ! outside & ! refraction 9 ! glass1 z ! light pass$ ?r\gh x to ! mirror & back aga91 correct$ ! sph]ical ab]ration ( ! mirror$ surface4 ,^! h be5 ext5sively us$4 ,_m comb9ations ( curv$ surfaces h be5 develop$ = special projection purposes1 b ! p>abolic mirror is /ill 9 favor = p[]ful se>*-lights4 ,! tip ( ! positive c>bon is plac$ at its focus & ! effective angle 9 :i* light is int]cept$ by ! mirror is g5]ally ab\t #abe degrees4 ,)9 ?is angle is includ$ a l>ge portion ( ! light emitt$ by ! light-s\rce 9 ! case ( direct-curr5t arcs4 ,if ?is angle is increas$ = a mirror ( a giv5 diamet] by decreas+ its focal l5g?1 ! div]g5ce ( ! beam is increas$ & ! beam-int5sity is dim9i%$4 ,?is is due to ! fact t ! light-s\rce n[ becomes app>5tly l>g]2 t is1 be+ ( a giv5 size x n[ subt5ds a l>g] angle at ! reflector & dep>ts m f ! !oretical po9t4 ,:5 ! rec5t w> began ! se>*-lights available 7 int5d$ g5]ally = fix$ in/allations4 ,^! 7 b>rel lights ) reflectors sev]al feet 9 diamet]1 ! :ole output sometimes weigh+ z mu* z sev]al tons4 ,%ortly aft] ! entrance ( ?is c\ntry into ! w>1 a mobile b>rel se>*-light five feet 9 diamet] 0 produc$1 :i*1 complete ) c>riage1 weigh$ only #ahjj p\nds4 ,lat] !re 7 fur!r improvem5ts4 ,an example ( ! impetus :i* ! /ress ( w> gives to te*nical accompli%m5ts is f\nd 9 ! developm5t ( a p>ticul> mobile se>*light4 ,two mon?s aft] ! ,w> ,dep>tm5t submitt$ ! problems ( design to c]ta9 l>ge indu/rial e/abli%m5ts a new #fj-;in* se>*-light 0 plac$ 9 production4 ,x weigh$ "o fif? z mu* z ! previ\s /&>d2 x _h "o tw5tie? ! bulk2 x 0 mu* simpl]2 x c\ld be built 9 "o f\r? ! "t2 & x co/ half z mu*4 ,remote control ( ! app>atus has be5 highly develop$ 9 ord] t ! op]ator may be at a di/ance f ! scatt]$ light ne> ! unit4 ,if he is ne> ! se>*-light1 ?is veil ( diffus$ light v s]i\sly int]f]es ) 8 vision4 ,mobile p[]-units 7 necess>y & ! types develop$ us$ ! automobile eng9e z ! prime mov]4 ,9 "o ! g5]ator is locat$ 9 front ( ! eng9e & support$ beyond ! automobile *assis4 ,9 ano!r type ! g5]ator is locat$ betwe5 ! automobile transmission & ! diff]5tial4 ,a /&>d clut* & ge>-%ift lev] is employ$ to connect ! eng9e ei!r ) ! g5]ator or ) ! propell] %aft ( ! truck4 ,! fir/ type includ$ a #aae-volt1 #ae-kil[att g5]ator1 a #cf-;in* :eel b>rel se>*-light1 & #ejj feet ( wire cable4 ,! second type includ$ a #aje-volt1 #bj-kil[att g5]ator1 a #fj-;in* op5 se>*light1 & #fjj feet ( cable4 ,?is type has be5 ext5d$ 9 magnitude to include a #ej-kil[att g5]ator4 ,:5 ^! units are mov$1 ! se>*-light & its c>riage are load$ ^u ! re> ( ! mobile g5]at+ equipm5t4 ,an idea ( ! int5sities obta9able ) ! l>ge/ app>atus is ga9$ f illum9ation produc$ at a giv5 di/ance4 ,= example1 ! #ae-kil[att se>*-light ) highly conc5trat$ beam1 produc$ an illum9ation at #icj feet ( #bhj foot-c&les4 ,at ?is po9t ?is is ! equival5t ( ! illum9ation produc$ by a s\rce hav+ a lum9\s int5sity ( ne>ly #bej1jjj1jjj c&les4 ,( c\rse1 ! range at :i* se>*-lights are effective is ! factor ( mo/ importance1 b ?is dep5ds ^u a numb] ( conditions su* z ! illum9ation produc$ by ! beam at v>i\s di/ances1 ! atmosph]ic conditions1 ! position ( ! obs]v]1 ! size1 patt]n1 color1 & reflection-factor ( ! object1 & ! color1 patt]n1 & reflection-factor ( ! backgr\nd4 ,^! are too involv$ to be discuss$ "h1 b x may be /at$ t "u ord9>y conditions ^! p[]ful lights are effective at di/ances ( sev]al miles4 ,accord+ to rec5t "w1 x appe>s t ! range ( a se>*-light 9 reveal+ a giv5 object "u fix$ conditions v>ies ab\t z ! f\r? root ( its int5sity4 ,al?\gh ! metallic p>abolic reflector is us$ 9 ! mo/ p[]ful se>*-lights1 !re h be5 _m o!r developm5ts adapt$ to w>f>e4 ,fresnel l5ses h be5 us$ above ! arc = se>*-lights ^: beams are direct$ upw>d 9 se>* ( aircraft1 ?us replac+ ! mirror bel[ ! arc1 :i*1 ow+ to its position1 is always 9 dang] ( det]ioration by ! hot c>bon p>ticles dropp+ ^u x4 ,= %ort ranges inc&esc5t filam5t lamps h be5 us$ ) success4 ,oxyacetyl5e equipm5t has f\nd application1 ow+ to its portability4 ,! oxyacetyl5e flame is conc5trat$ ^u a small pellet ( c]ia1 :i* provides a brilliant s\rce ( small dim5sions4 ,a tank conta9+ ab\t #ajjj lit]s ( dissolv$ acetyl5e & ano!r conta9+ ab\t #aajj lit]s ( oxyg5 supply ! fuel4 ,a beam hav+ an int5sity ( ab\t #a1ejj1jjj c&les is obta9$ ) a consumption ( #dj lit]s ( ea* ( ! gases p] h\r4 ,at ?is rate ! se>*-light may be op]at$ tw5ty h\rs )\t repl5i%+4 ,al?\gh ! beacon-light = nocturnal airm5 is a developm5t :i* w assume mu* importance 9 peaceful activities1 x 0 develop$ *iefly to meet ! requirem5ts ( w>f>e4 ,^! d n diff] mat]ially f ^? :i* guide ! m>9]1 except t ! travel] 9 ! arial ocean is f> above ! plane on :i* ! beacon re/s4 ,= ?is reason ! l5ses are design$ to s5d light g5]ally upw>d4 ,9 =eign c\ntries sev]al types ( beacons = arial navigation h be5 9 use4 ,9 "o ! light f ! s\rce is freely emitt$ 9 all upw>d directions1 b ! light normally emitt$ into ! l[] hemisph]e is turn$ upw>d by means ( prisms4 ,9 a m elaborate type1 belts ( l5ses are arrang$ s z to s5d light 9 all directions above ! horizontal plane4 ,a fla%+ app>atus is us$ to designate ! locality by ! numb] or "* ( ! fla%es4 ,electric filam5ts & acetyl5e flames h be5 us$ z ! light-s\rces = ?is purpose4 ,9 ano!r type ! light is conc5trat$ 9 "o azimu? & ! :ole beacon is revolv$4 ,portable beacons employ+ gas 7 us$ dur+ ! w> on "s ( ! fly+-fields ne> ! battle front4 ,all k9ds ( light+ & light+-devices 7 us$ dep5d+ ^u ! ne$s & mat]ial available4 ,ev5 self-lum9\s pa9t 0 us$ = v>i\s purposes at ! front1 z well z = illum9at+ wat*-dials & ! scales ( in/rum5ts4 ,wood5 buttons two or ?ree in*es 9 diamet] cov]$ ) self-lum9\s pa9t c\ld be fix$ :]ev] desir$ & ?us s]ve z l&m>ks4 ,!y are visible only at %ort di/ances & ! feebl5ess ( _! light made !m p>ticul>ly valuable = v>i\s purposes at ! battle front4 ,!y c\ld be us$ 9 ! h& = giv+ optical signals at a %ort di/ance :]e sil5ce 0 ess5tial4 ,self-lum9\s arr[s & signs direct$ troops & trucks at night & ev5 /ret*]-be>]s h borne self-lum9\s m>ks on _! backs 9 ord] to id5tify !m to _! fri5ds4 ,some:at analog\s to ?is application ( lum9\s pa9t is ! use ( blue light at night on battle-%ips & o!r vessels 9 action or ne> ! enemy4 ,sev]al ye>s ago a ,brazilian battle-%ip built 9 ?is c\ntry 0 equipp$ ) a dual light+-sy/em4 ,! extra "o us$ deep-blue light1 :i* is v effective = eyes adapt$ to d>kness or to v l[ int5sities ( illum9ation & is a %ort-range light4 ,ow+ to ! l[ lum9\s int5sity ( ! blue lights !y d n c>ry f>2 & fur!rmore1 x is well e/abli%$ t blue light does n p5etrate z f> ?r\gh ord9>y atmosph]e z lights ( o!r colors ( ! same int5sity4 ,! w> has be5 responsible = great /rides 9 c]ta9 directions 9 ! developm5t & use ( artificial light & ! era ( peace w inh]it ^! developm5ts & w adapt !m to m con/ructive purposes4 ,,xv ,,signal+ ,f e>lie/ times ! beacon-fire has s5t =? messages f hilltops or across inaccessible places4 ,9 ?is c\ntry1 :5 ! ,indian 0 mon>* ( ! va/ areas ( =e/ & prairie1 he spread news broadca/ to rov+ tribesm5 by means ( ! signal-fire1 & he fla%$ 8 code by cov]+ & uncov]+ x4 ,ca/aways1 :e!r 9 fiction or 9 reality1 in/9ctively turn to ! beacon-fire z a mode ( attract+ a pass+ %ip4 ,on e h& ?r\gh\t ! ages ?is simple means ( communication has be5 employ$2 !re=e1 x is n surpris+ t mank9d has appli$ 8 +5uity to ! p]fection ( signal+ by means ( light1 :i* has its own peculi> fields & advantages4 ,( c\rse1 wireless telephony & telegraphy w replace light-signal+ to "s ext5t1 b !re are _m fields 9 :i* ! la/-nam$ is /ill supreme4 ,9 fact1 dur+ ! rec5t w> mu* use 0 made ( light 9 ?is mann] & devices 7 develop$ despite ! _m o!r available means ( signal+4 ,"o ( ! *ief advantages ( light z a signal is t x is s easily controll$ & direct$ 9 a /raight l9e4 ,wireless waves1 = example1 are radiat$ broadca/ to be int]cept$ by ! enemy4 ,! beg9n+ ( light-signal+ is hidd5 9 ! obscurity ( ! pa/4 ,( c\rse1 ! mo/ primitive light-signals 7 wood fires1 b x is likely t man e>ly utiliz$ ! mirror to reflect ! sun's image & ?us laid ! f\ndation ( ! mod]n heliograph4 ,! ,book ( ,job1 :i* is probably "o ( ! olde/ writ+s available1 m5tions molt5 mirrors4 ,! ,egyptians 9 ! "t ( ,moses us$ mirrors ( poli%$ brass4 ,euclid 9 ! ?ird c5tury be=e ! ,*ri/ian era is said to h writt5 a treatise 9 :i* he discuss$ ! reflection ( light by concave mirrors4 ,john ,peckham1 ,ar*bi%op ( ,cant]bury 9 ! ?irte5? c5tury1 describ$ mirrors ( poli%$ /eel & ( glass back$ ) lead4 ,mirrors ( glass coat$ ) an alloy ( t9 & m]cury 7 made by ! ,v5etians 9 ! sixte5? c5tury4 ,huyg5s 9 ! sev5te5? c5tury /udi$ ! laws ( refraction & reflection & devis$ optical app>atus = v>i\s purposes4 ,h[ev]1 x 0 n until ! eighte5? c5tury t any notewor?y attempts 7 made to control artificial light = practical purposes4 ,dollond 9 #ageg 0 ! fir/ to make a*romatic l5ses by us+ comb9ations ( diff]5t glasses4 ,lavoisi] 9 #aggd made a l5s ab\t f\r feet 9 diamet] by con/ruct+ a cell ( two concave glasses & fill+ x ) wat] & o!r liquids4 ,x is said t he ignit$ wood & melt$ metals by conc5trat+ ! sun's image ^u !m by means ( ?is l5s4 ,ab\t t "t ,buffon made a built-up p>abolic mirror by means ( sev]al hundr$ small plane mirrors set at ! prop] angles4 ,) ?is he set fire to wood at a di/ance ( m ?an two hundr$ feet by conc5trat+ ! sun's rays4 ,he is said also to h made a l5s f a solid piece ( glass by gr9d+ x 9 conc5tric /eps simil> to ! designs work$ out by ,fresnel sev5ty ye>s lat]4 ,^! are examples ( ! e>ly "w :i* laid ! f\ndation = ! highly p]fect$ control ( light ( ! pres5t "t4 ,:ile engag$ 9 ! survey ( ,irel&1 ,?omas ,drummond 9 #ahbf devis$ app>atus = signal+ _m miles1 ?us facilitat+ triangulation4 ,di/ances z great z eighty miles 7 enc\nt]$ & x appe>$ desirable to h "s me?od = see+ a po9t at ^! great di/ances4 ,gauss 9 #ahbb us$ ! reflection ( ! sun's image f a plane mirror & ,drummond also tri$ ?is means4 ,! latt] 0 successful 9 signal+ #de miles to a /ation :i* because ( haze c\ld n be se51 or ev5 ! hill ^u :i* x re/$4 ,hav+ demon/rat$ ! feasibility ( ! plan1 he set ab\t mak+ a device :i* w\ld include a p[]ful artificial light 9 ord] to be indep5d5t ( ! sun4 ,9 e>li] geodetic surveys ,arg& lamps _h be5 employ$ ) p>abolic reflectors & ) convex l5ses1 b app>5tly ^! did n h a suffici5t range4 ,fresnel & ,arago con/ruct$ a l5s consi/+ ( a s]ies ( conc5tric r+s :i* 7 cem5t$ toge!r1 & on plac+ ?is be=e an ,arg& lamp possess+ f\r conc5tric wicks1 !y obta9$ a light :i* 0 obs]v$ at =ty-eight miles4 ,despite ^! successes1 ,drummond believ$ ! p>abolic mirror & a m p[]ful light-s\rce af=d$ ! be/ comb9ation = a signal-light4 ,9 se>*+ = a brilliant light-s\rce he exp]im5t$ ) phosphorus burn+ 9 oxyg5 & ) v>i\s brilliant pyrote*nical prep>ations4 ,h[ev]1 flames 7 un/eady & g5]ally unsuitable4 ,he !n turn$ 9 ! direction :i* l$ to 8 developm5t ( ! lime-light4 ,9 8 fir/ app>atus he us$ a small sph]e ( lime 9 an alcohol flame & direct$ a jet ( oxyg5 ?r\gh ! flame ^u ! lime4 ,he !reby obta9$1 accord+ to 8 own description 9 #ahbf1 a light s int5se t :5 plac$ 9 ! focus ( a reflector ! eye c\ld ) difficulty support its spl5dor1 ev5 at a di/ance ( =ty feet1 ! cont\r be+ lo/ 9 ! brilliancy ( ! radiation4 ,he !n cont9u$ to exp]im5t ) v>i\s oxides1 includ+ zirconia1 magnesia1 & lime f *alk & m>ble4 ,?is 0 ! adv5t ( ! lime-light1 :i* %\ld be> ,drummond's "n because x 0 "o ( ! greate/ /eps 9 ! evolution ( artificial light4 ,by means ( ?is app>atus 9 ! survey1 signals 7 r5d]$ visible at di/ances z great z "o hundr$ miles4 ,drummond propos$ ! use ( ?is light-s\rce 9 ! important ligh?\ses at t "t & =esaw _m o!r applications4 ,! lime-light ev5tually 0 ext5sively us$ z a light-signal+ device4 ,! heliograph1 :i* utilizes ! sun z a light-s\rce1 has be5 widely us$ z a light-signal+ app>atus & ,drummond p]haps 0 ! fir/ to utilize artificial light ) x4 ,! disadvantage ( ! heliograph is ! undep5dability ( ! sun4 ,) ! adoption ( artificial light1 v>i\s optical devices h come into use4 ,philip ,colomb p]haps is des]v+ ( ! cr$it ( initiat+ mod]n signal+ by fla%+ a code4 ,he began "w on su* a sy/em 9 #aheh & z an (fic] 9 ! ,briti% ,navy work$ h>d to introduce x4 ,f9ally1 9 #ahfg1 ! ,briti% ,navy adopt$ ! fla%+-sy/em1 9 :i* a light-s\rce is expos$ & eclips$ 9 su* a mann] z to repres5t dots & da%es analog\s to ! ,morse code4 ,at fir/ ! rate ( transmission ( words 0 f sev5 to t5 p] m9ute4 ,rec5tly mu* m s5sitive app>atus is available1 & ) su* devices ! rate is limit$ only by ! sluggi%ness ( ! visual process4 ,?is initial sy/em 0 v successful 9 ! ,briti% ,navy & x 0 soon f\nd t a fleet c\ld be h&l$ ) ease & safety 9 d>kness or 9 fog4 ,inasmu* z ! dot-&-da% sy/em requires only two elem5ts1 x may be transmitt$ by v>i\s means4 ,a lant]n may be swung 9 %ort & long arcs or dipp$ accord+ly4 ,! bl9k] or pulsat+ light-signal consi/s ( a s+le light-s\rce me*anically occult$4 ,x is controll$ by means ( a telegraph-key & ! code may be rapidly transmitt$4 ,! se>*-light af=ds a means = signal+ great di/ances1 ev5 9 ! daytime4 ,! light is usually me*anically occult$ by a quick-act+ %utt]1 b rec5tly ano!r sy/em has be5 devis$4 ,9 ! latt] ! light itself is controll$ by means ( an electrical %unt across ! arc4 ,9 ?is mann] ! light is dimm$ by %unt+ mo/ ( ! curr5t1 !reby produc+ ! same effect z actually eclips+ ! light ) a me*anical %utt]4 ,by means ( ! se>*-light signals are usually visible z f> z ! limitations ( ! e>?'s curvature w p]mit4 ,by direct+ ! beam aga9/ a cl\d1 signals h be5 obs]v$ at a di/ance ( "o hundr$ miles f ! se>*-light despite int]v5+ elevat$ l& or ! curvature ( ! ocean's surface4 ,by means ( small se>*-lights x is easy to s5d signals t5 miles4 ,?is k9d ( app>atus has ! advantage ( be+ selective2 t is1 ! signals are n visible to p]sons a few degrees f ! direction ( ! beam4 ,"o ( ! mo/ rec5t developm5ts has be5 a special tung/5 filam5t 9 a gas-fill$ bulb plac$ at ! focus ( a small p>abolic mirror4 ,! beam is direct$ by means ( sights & ! fla%es are obta9$ by int]rupt+ ! curr5t by means ( a trigg]-swit*4 ,! filam5t is s s5sitive t signals may be s5t fa/] ?an ! physiological process ( vision w record4 ,) ! adv5t ( wireless telegraphy light-signal+ = long di/ances 0 tempor>ily eclips$1 b dur+ ! rec5t w> x 0 reviv$ & mu* developm5t "w 0 prosecut$4 ,! ,ardois sy/em consi/s ( f\r lamps m\nt$ 9 a v]tical l9e z high z possible4 ,ea* lamp is d\ble1 conta9+ a r$ & a :ite light1 & ^! lights are controll$ f a keybo>d4 ,a r$ light indicates a dot 9 ! ,morse code & a :ite light indicates a da%4 ,! keys are numb]$ & lett]$1 s t ! sy/em may be op]at$ by any "o4 ,v>i\s o!r sy/ems employ+ color$ lights h be5 us$1 b !y are necess>ily %ort-range signals4 ,ano!r example is ! semaphore4 ,:5 us$ at night1 tung/5 lamps 9 reflectors indicate ! positions ( ! arms4 ,! advantage ( ^! signals ov] ! fla%+-sy/em is t ea* signal is complete & easy to foll[4 ,! fla%+-sy/em is progressive & mu/ be c>efully foll[$ 9 ord] to obta9 ! mean+ ( ! dots & da%es4 ,small] signal-lamps us+ acetyl5e h be5 employ$ 9 ! =e/ry s]vice & 9 o!r activities :]e a portable device is necess>y4 ,9 "o type1 a mixture-tank conta9+ calcium c>bide & wat] is ( suffici5t capacity = ?ree h\rs ( signal+4 ,a small pilot-light is p]mitt$ to burn con/antly & ! fla%es are obta9$ by op]at+ a key :i* increases ! gas-pressure4 ,! light fl>es z long z ! key is depress$4 ,! range ( ?is app>atus is f t5 to tw5ty miles4 ,an electric lamp suppli$ f a /orage batt]y has be5 design$ = geodetic op]ations 9 m\nta9\s di/ricts :]e x is desir$ to s5d signals z f> z "o hundr$ miles4 ,te/s %[ t ?is device is a hundr$ & fifty times m p[]ful ?an ! ord9>y acetyl5e signal-lamp1 & x is ?\ght t ) ?is new electric lamp haze & smoke w seldom prev5t obs]vations4 ,c]ta9 fix$ lights are requir$ by law on a vessel at night4 ,:5 x is "u way !re mu/ be a :ite light at ! ma/head1 a />bo>d gre5 light1 a port r$ light1 a :ite range-light1 & a :ite light at ! /]n4 ,! ma/head light is design$ to emit light ?r\gh a horizontal arc ( tw5ty po9ts ( ! compass1 t5 on ea* side ( dead ahead4 ,?is light mu/ be visible at a di/ance ( five miles4 ,! port & />bo>d lights op]ate ?r\gh a horizontal arc ( tw5ty po9ts ( ! compass1 ! middle ( :i* is dead ahead4 ,!y are scre5$ s z n to be visible across ! b[ & !y mu/ be int5se en\gh to be visible two miles ahead4 ,! ma/head light is c>ri$ on ! =ema/ & ! range-light on ! ma9ma/1 at an elevation fifte5 feet high] ?an ! =m]4 ,! range-light emits light t[>d all po9ts ( ! compass & mu/ be int5se en\gh to be se5 at a di/ance ( ?ree miles4 ,! /]n light is simil> to ! ma/head1 b its light mu/ n be visible =w>d ( ! beam4 ,:5 a vessel is t[+ ano!r x mu/ display two or ?ree lights 9 a v]tical l9e ) ! ma/head light & simil> to x4 ,! lights are spac$ ab\t six feet ap>t1 & two extra ones indicate a %ort t[ & ?ree a long "o4 ,a vessel ov] a hundr$ & fifty feet long :5 at an*or is requir$ to display a :ite light =w>d & aft1 ea* visible ar\nd ! entire horizon4 ,^! & _m o!r specifications indicate h[ artificial light in=ms ! m>9] & makes = ord] 9 %ipp+4 ,)\t artificial light ! wat]ways w\ld be trackless & *aos w\ld reign4 ,! di/ress signals ( a vessel are rockets1 b any burn+ flame also s]ves if rockets are unavailable4 ,fireworks 7 kn[n _m c5turies ago & d\btless ! possibilities ( signal+ by means ( rockets h long be5 recogniz$4 ,an e>ly in/ance ( sci5tific int]e/ 9 rockets & _! usefulness is t ( ,b5jam9 ,rob9s 9 #agdi4 ,:ile he 0 witness+ a display ( fireworks 9 ,london x occurr$ to him t x w\ld be ( int]e/ to measure ! height to :i* ! rockets asc5d$ & to det]m9e ! ranges at :i* !y 7 visible4 ,8 measurem5ts indicat$ t ! rockets asc5d$ usually to a height ( #ddj y>ds1 b "s ( !m atta9$ altitudes z high z #fae y>ds4 ,he !n _h "s special ones made & despat*$ lett]s to fri5ds 9 ?ree diff]5t localities1 at di/ances z great z #ej miles1 ask+ !m to obs]ve at a c]ta9 "t1 :5 ! rockets 7 to be s5t up 9 ! outskirts ( ,london4 ,"s ( ^! rockets rose to altitudes z great z #fjj y>ds & 7 di/9ctly se5 by obs]v]s #ch miles away4 ,lat] he made rockets :i* asc5d$ z high z #abjj y>ds & conclud$ t ?is 0 a practical means ( signal+4 ,s9ce t "t & especially dur+ ! rec5t w>1 rockets h s]v$ well 9 signal+ messages4 ,! self-propell$ rockets h n be5 alt]$ 9 ess5tial features s9ce ! remote c5turies :5 ! ,*9ese fir/ us$ !m 9 celebrations4 ,a cyl9drical %ell is m\nt$ on a wood5 /ick & :5 ! p[d] 9 ! %ell burns ! hot gases are eject$ s viol5tly d[nw>d t ! reaction drives ! %ell upw>d4 ,at a c]ta9 po9t 9 ! air1 v>i\s signals bur/ =?1 :i* v>y 9 "* & color4 ,"o ( ! advantages ( ! rocket is t x conta9s )9 itself ! =ce ( propulsion2 t is1 no gun is necess>y to project x4 ,! illum9at+ comp\nds & v>i\s details are simil> to ^? ( ! illum9at+ %ells describ$ 9 ano!r *apt]4 ,at pres5t ! rocket is n sci5tifically design$ to obta9 ! greate/ effici5cy ( propulsion1 b its simplicity 9 ?is respect is "o ( its *ief advantages4 ,if ! self-propell$ rocket becomes ! projectile ( ! future1 z "s h v5tur$ to pr$ict1 mu* consid]ation mu/ be giv5 to ! design ( ! orifice ?r\gh :i* ! gases viol5tly escape 9 ord] t ! be/ effici5cy ( propulsion may be atta9$4 ,!re are o!r details 9 :i* improvem5ts may be made4 ,! combu/ion products ( ! black p[d] :i* are n gase\s equal ab\t "o ?ird ! weight ( ! p[d]4 ,?is repres5ts ineffici5t propulsion4 ,fur!rmore1 dur+ rec5t ye>s mu* in=mation has be5 ga9$ p]ta9+ to ! air-resi/ance :i* c be appli$ to advantage 9 design+ ! =m ( rockets4 ,besides ! v>i\s rockets1 signal-lights h be5 con/ruct$ to be fir$ f guns & pi/ols4 ,dur+ ! rec5t w> ! airman 9 ! d>k heights us$ ! pi/ol signal-light effectively = communication4 ,^! devices emitt$ />s ei!r s+ly or 9 succession1 & ! color ( ^! />s z well z _! numb] & sequ5ce gave significance to ! signal4 ,"s ( ^! light-signals 7 provid$ ) p>a*utes & 7 long-burn+2 t is1 light 0 emitt$ = a m9ute or two4 ,!re are _m v>iations possible & a great _m diff]5t k9ds ( light-signals ( ?is "* 7 us$4 ,9 ! front-l9e tr5*es & 9 advances !y 7 us$ :5 telephone s]vice 0 unavailable4 ,! airman direct$ artill]y fire by means ( 8 pi/ol-light4 ,rockets br\ght aid to ! f\nd]$ %ip or to ! life-boats4 ,! signal-tube :i* burn$ r$1 gre51 or :ite 0 held 9 ! h& or laid on ! gr\nd & x (t5 told its /ory4 ,= _m ye>s su* a device dropp$ f ! re> ( ! railroad tra9 has kept ! foll[+ tra9 at a safe di/ance4 ,a device 0 tri$ out 9 ! tr5*es1 dur+ ! w>1 :i* emitt$ a flame4 ,?is c\ld be v>i$ 9 color to s]ve z a signal & ! app>atus _h suffici5t capacity = ?irty h\rs' burn+4 ,?is c\ld also be us$ z a weapon1 or :5 r$uc$ 9 int5sity x s]v$ z a fla%-light4 ,= _m ye>s exp]im5ts h be5 made ^u ! use ( ! invisible rays :i* accompany visible rays4 ,! practicability ( signal+ ) invisible rays dep5ds ^u produc+ !m effici5tly 9 suffici5t quantity & ^u sep>at+ !m f ! visible rays :i* accompany !m4 ,"s successful results 7 obta9$ ) a #f-volt electric lamp possess+ a coil$ filam5t at ! focus ( a l5s ?ree in*es 9 diamet] & twelve in*es 9 focal l5g?4 ,?is gave a v n>r[ beam visible only 9 ! neighborhood ( ! obs]vation po/ to :i* ! signals 7 direct$4 ,! beam 0 direct$ by telescopic sights4 ,dur+ ! day a deep r$ filt] 0 plac$ ov] ! lamp & ! light 0 invisible to an obs]v] unless he 0 equipp$ ) a simil> r$ scre5 to elim9ate ! daylight4 ,x is said t signals 7 di/+ui%$ at a di/ance ( six miles4 ,by night a scre5 0 us$ :i* transmitt$ only ! ultraviolet rays1 & ! obs]v]'s telescope 0 provid$ ) a fluoresc5t scre5 9 its focal plane4 ,! ultraviolet rays fall+ ^u ?is scre5 7 trans=m$ into visible rays by ! ph5om5on ( fluoresc5ce4 ,! range ( ?is device 0 ab\t six miles4 ,= naval convoys lamps are requir$ to radiate t[>d all po9ts ( ! compass4 ,= ?is purpose a qu>tz m]cury-arc :i* is ri* 9 ultraviolet rays 0 surr\nd$ ) a *imney :i* transmitt$ ! ultraviolet rays effici5tly & absorb$ all visible rays except+ violet light4 ,! lamp appe>$ a deep violet color at close range1 b ! fa9tly visible light :i* x transmitt$ 0 n se5 at a di/ance4 ,a di/ant obs]v] picks up ! invisible ultraviolet light by means ( a special optical device hav+ a fluoresc5t scre5 ( b>ium-plat9o-cyanide4 ,?is device _h a range ( ab\t f\r miles4 ,light-signals are ess5tial = ! op]ation ( railways at night & !y h be5 9 use = _m ye>s4 ,9 ?is field ! significance ( light-signals is bas$ almo/ univ]sally on color4 ,! sett+ ( a swit* is indicat$ by ! color ( ! light t x %[s4 ,) ! introduction ( ! semaphore sy/em1 9 :i* dur+ ! day ! position ( ! arm is significant1 color$ glasses 7 plac$ on ! opposite end ( ! arm 9 su* a mann] t a c]ta9 color$ glass w\ld appe> be=e ! light-s\rce = a c]ta9 position ( ! arm4 ,a k]os5e flame beh9d a glass l5s 0 ! lamp us$1 &1 = example1 r$ meant ,/op1 gre5 c\nsel$ ,caution1 & cle> or :ite indicat$ ,all cle>4 ,= _m ye>s ! k]os5e lamp has be5 us$1 b rec5tly ! electric filam5t lamp is be+ in/all$ to "s ext5t = ?is purpose4 ,9 fact1 on "o railroad at lea/1 tung/5 lamps are us$ = light-signals by day z well z by night4 ,?ree signals--r$1 gre51 & :ite--are plac$ 9 a v]tical l9e & beh9d ea* l5s are two lamps1 "o op]at+ at high effici5cy & "o at l[ effici5cy to insure aga9/ ! failure ( ! signal4 ,! normal daylight range is ab\t ?ree ?\s& feet & "u ! wor/ conditions :5 oppos$ to direct sunlight1 ! range is n less ?an two ?\s& feet4 ,x is said t ^! lights are se5 m easily ?an semaphore arms "u all circum/ances & t !y %[ two or ?ree times z f> z ! latt] dur+ a sn[-/orm4 ,! /&>d colors = light-signals z adopt$ by ! ,railway ,signal ,association are r$1 yell[1 gre51 blue1 purple1 & lun> :ite4 ,^! are specifi$ z to ! am\nt ( ! v>i\s spectral colors :i* !y transmit :5 ! light-s\rce is ! k]os5e flame4 ,obvi\sly1 ! colors g5]ally appe> diff]5t :5 ano!r illum9ant is us$4 ,! blue & purple are %ort-range signals1 b ! effective range ( ! be/ railway signal employ+ a k]os5e flame is only ab\t f\r miles4 ,x has be5 %[n t ! visibility ( po9t s\rces ( :ite light 9 cle> atmosph]e1 = di/ances up to a mile at lea/1 is proportional to _! c&le-p[] & inv]sely proportional to ! squ>e ( ! di/ance4 ,app>5tly ! lum9\s int5sities ( signal-lamps requir$ 9 cle> wea!r 9 ord] t !y may be visible mu/ be #j4dc c&les = "o nautical mile1 #a4ge c&les = two nautical miles1 & #aa c&les = five nautical miles4 ,f ! data available x appe>s t a r$ or a :ite signal-light w be easily visible at a di/ance 9 nautical miles equal to ! squ>e root ( its c&le-p[] 9 t direction4 ,! range 9 nautical miles ( a gre5 light app>5tly is proportional to ! cube root ( ! c&le-p[]4 ,:e!r or n ^! relations betwe5 ! range 9 miles & ! lum9\s int5sity 9 c&les hold = great] di/ances ?an ^? ord9>ily enc\nt]$ has n be5 det]m9$1 b x is int]e/+ to note t ! squ>e root ( ! lum9\s int5sity ( ! ,naves9k ,light at ! entrance to ,new ,york ,h>bor is ab\t #gjjj4 ,c\ld ?is light be se5 at a di/ance ( sev5 ?\s& miles ?r\gh ord9>y atmosph]e8 ,! mo/ di/9ctive color$ lights are r$1 yell[1 gre51 & blue4 ,to ^! :ite 7cle>7 & purple h be5 add$ = signal+-purposes4 ,yell[ is int5se1 b x may be confus$ ) :ite or cle>4 ,blue & purple z obta9$ f ! pres5t practicable light-s\rces are ( l[ int5sity4 ,?is leaves r$1 gre51 & cle> z ! mo/ g5]ally satisfactory signal-lights4 ,!re are num]\s o!r applications1 especially indoors4 ,"s ( ^! h be5 devis$ = special ne$s1 b !re are _m o!rs :i* are g5]al1 su* z = elevators1 telephones1 v>i\s call sy/ems1 & traffic signals4 ,light has ! advantages ( be+ sil5t & controllable z to position & direction1 & ( be+ a visible signal at night4 ,?us1 9 ano!r field artificial light has respond$ to ! dem&s ( civilization4 ,,xvi ,,! ,,co/ ,,( ,,light ,artificial light is s sup]ior to natural light 9 _m respects t mank9d has acquir$ ! habit ( retir+ _m h\rs aft] d>kness has fall51 a result ( :i* has br\ght =? ! issue kn[n z daylight sav+4 ,d\btless1 daylight %\ld be us$ :5ev] possible1 b !re are two sides to ! "q4 ,9 ! fir/ place1 x co/s some?+ to br+ daylight indoors4 ,! ar*itectural con/ruction ( w9d[s & skylights increases ! co/ ( daylight4 ,light-c\rts1 by sacrific+ valuable floor-area1 add to ! exp5se4 ,! ma9t5ance ( w9d[s & sky lights is an appreciable item4 ,consid]+ ^! & o!r factors1 x c be se5 t daylight indoors is exp5sive2 & z x is also undep5dable1 a supplem5t>y sy/em ( artificial light+ is g5]ally necess>y4 ,9 fact1 x is easy to %[ 9 "s cases t artificial light+ is *eap] ?an natural light+4 ,! av]age middle-class home is n[ light$ artificially = ab\t #ae4jj to #be4jj p] ye>1 ) conv5i5t light-s\rces :i* are available at all times4 ,!re is no item 9 ! h\sehold budget :i* returns z mu* satisfaction1 com=t1 & happ9ess 9 proportion to its co/ z artificial light4 ,x is an arti/ic m$ium ( great pot5tiality1 & light 9 a n>r[ utilit>ian s5se is always a by-product ( arti/ic light+4 ,! insignificant co/ ( mod]n light+ may be emphasiz$ 9 _m ways4 ,! int]e/ on ! inve/m5t 9 a picture or a vase :i* co/ #be4jj w usually cov] ! co/ ( op]at+ any decorative lamp 9 ! home4 ,a great proportion ( ! inve/m5t 9 p]sonal prop]ty 9 a home is *>geable to an attempt to beautify ! surr\nd+s4 ,! int]e/ on only a small portion ( ?is inve/m5t w pay = arti/ic & utilit>ian artificial light+ 9 ! home4 ,! co/ ( wa%+ ! w9d[s ( ! av]age h\se may be z great z ! co/ ( artificial light+ & is usually at lea/ a l>ge fraction ( ! latt]4 ,x w\ld become monoton\s to cite ! v>i\s examples ( ! insignificant co/ ( artificial light & its high return to ! us]4 ,! example ( ! home has be5 *os5 because ! read] may easily c>ry ! analysis fur!r4 ,! indu/ries :]e co/s are analyz$ are n[ look+ ^u adequate & prop] light+ z an asset :i* br+s 9 pr(its by increas+ production1 by decreas+ spoilage1 & by decreas+ ! liability ( accid5ts4 ,inasmu* z daylight sav+ became an issue dur+ ! rec5t w> & is likely to rema9 a matt] ( conc]n1 its hi/ory is int]e/+4 ,"o ( ! out/&+ diff]5ces betwe5 primitive & civiliz$ be+s is _! h\rs ( activities4 ,! =m] automatically adju/$ !mselves to daylight1 b z civilization advanc$1 ! span ( activities began to ext5d m & m beyond ! com+ ( d>kness4 ,f9ally 9 _m activities ! "w-day 0 ext5d$ to tw5ty-f\r h\rs4 ,!re c be no insurm\ntable objection to work+ at night ) a prop] arrangem5t ( ! p]iods ( "w2 9 fact1 ! co/ ( liv+ w\ld be greatly increas$ if ! ov]head *>ges repres5t$ by su* items z ma*9]y & build+s 7 all[$ to be c>ri$ by ! decreas$ products ( a %ort5$ p]iod ( production4 ,!re _c be any basic objection to artificial light+1 because mo/ factories1 = example1 may be bett] illum9at$ by artificial ?an by natural light4 ,( c\rse1 ! lag ( com=table temp]ature beh9d daylight is responsible to "s ext5t = a natural %ift+ ( ! ord9>y work+-day some:at beh9d ! sun4 ,! *ill ( dawn t5ds to keep mank9d 9 b$ & ! *e] ( artificial light & ! p]iod ( recreation 9 ! ev5+ t5ds to keep ! civiliz$ races out ( b$4 ,!re are p[]ful influ5ces always at "w & despite ! desirable features ( daylight-sav+1 mank9d w always t5d to lag4 ,z ye>s g by1 d\btless x w be necess>y to make ! %ift aga9 & aga94 ,x seems c]ta9 t ?r\gh\t ! c5turies ?\ghtful p]sons h se5 ! difficulty ( r\s+ man f 8 w>m b$ 9 ! e>ly morn+ & h recogniz$ a simple solution 9 turn+ ! h&s ( ! clock ahead4 ,among ! e>lie/ advocates ( daylight sav+ dur+ mod]n times1 :5 x became important en\gh to be consid]$ z an economic issue1 0 ,b5jam9 ,frankl94 ,9 #aghd he wrote a ma/]ful s]io-comic essay entitl$ ,an ,economical ,project :i* 0 publi%$ 9 ! ,j\rnal ( ,p>is4 ,! article1 :i* appe>$ 9 ! =m ( a lett]1 began ?us3 ,,messieurs3 ,y (t5 ent]ta9 u ) acc\nts ( new discov]ies4 ,p]mit me to communicate to ! public ?r\gh y\r pap] "o t has lately be5 made by myself & :i* ,i conceive may be ( great utility4 ,i 0 ! o!r ev5+ 9 a gr& company :]e ! new lamp ( ,messrs4 ,qu9quet & ,lange 0 introduc$ & mu* admir$ = its spl5dor2 b a g5]al inquiry 0 made :e!r ! oil x consum$ 0 n 9 exact proportion to ! light x af=d$1 9 :i* case !re w\ld be no sav+ 9 ! use ( x4 ,no "o pres5t c\ld satisfy u on t po9t1 :i* all agre$ ought to be kn[n1 x be+ a v desirable ?+ to less51 if possible1 ! exp5se ( light+ our ap>tm5ts1 :5 e o!r article ( family exp5se 0 s mu* augm5t$4 ,i 0 pleas$ to see ?is g5]al conc]n = economy1 = ,i love economy exce$+ly4 ,i w5t home1 & to b$1 ?ree or f\r h\rs aft] midnight1 ) my head full ( ! subject4 ,an accid5tal sudd5 noise wak$ me ab\t #f 9 ! morn+1 :5 ,i 0 surpris$ to f9d my room fill$ ) light1 & ,i imag9$ at fir/ t a numb] ( ^? lamps _h be5 br\ght into x2 b1 rubb+ my eyes1 ,i p]ceiv$ ! light came 9 at ! w9d[s4 ,i got up & look$ out to see :at might be ! occasion ( x1 :5 ,i saw ! sun j ris+ above ! horizon1 f :5ce he p\r$ 8 rays pl5tifully into my *amb]1 my dome/ic hav+ neglig5tly omitt$ ! prec$+ ev5+ to close ! %utt]s4 ,i look$ at my wat*1 :i* goes v well1 & f\nd t x 0 b #f o'clock2 &1 /ill ?9k+ x some?+ extraord9>y t ! sun %\ld rise s e>ly1 ,i look$ into ! almanac1 :]e ,i f\nd x to be ! h\r giv5 = 8 ris+ on t day4 ,i look$ =w>d1 too1 & f\nd he 0 to rise /ill e>li] e day till t[>d ! end ( ,june1 & t at no "t 9 ! ye> he ret>d$ 8 ris+ s long z till #h o'clock4 ,y\r read]s :o1 ) me1 h nev] se5 any signs ( sun%9e be=e noon1 & seldom reg>d ! a/ronomical "p ( ! almanac1 w be z mu* a/oni%$ z ,i 0 :5 !y he> ( 8 ris+ s e>ly1 & especially :5 ,i assure !m t he gives light z soon z he rises4 ,i am conv9c$ ( ?is4 ,i am c]ta9 ( my fact4 ,"o _c be m c]ta9 ( any fact4 ,i saw x ) my own eyes4 ,&1 hav+ repeat$ ?is obs]vation ! ?ree foll[+ morn+s1 ,i f\nd always precisely ! same result4 ,he !n cont9ues 9 ! same ve9 to %[ t le>n$ p]sons did n believe him & to po9t out ! difficulties :i* ! pione] enc\nt]s4 ,he br\ght out ! vital po9t by %[+ t if he _h n be5 awak5$ s e>ly he w\ld h slept six h\rs long] by ! light ( ! sun & 9 ex*ange he w\ld h liv$ six h\rs ! foll[+ night by c&le-light4 ,he !n mu/]$ ! little ari?metic he 0 ma/] ( & made "s s]i\s computations4 ,he assum$ z ! basis ( 8 computations t a hundr$ ?\s& families liv$ 9 ,p>is & ea* us$ a half-p\nd ( c&les nightly4 ,he %[$ t betwe5 ,m>* #bj? & ,septemb] #bj?1 #fd1jjj1jjj p\nds ( wax & tall[ c\ld be sav$1 :i* 0 equival5t to #ah1jjj1jjj4 ,aft] ^! s]i\s computations he amus+ly propos$ ! means = en=c+ ! daylight sav+4 ,obvi\sly1 x 0 necess>y to ar\se ! slugg>ds & 8 proposals includ$ ! use ( cannons & bells4 ,besides1 he propos$ t ea* family be re/rict$ to "o p\nd ( c&les p] week1 t coa*es w\ld n be all[$ to pass aft] sunset except ^? ( physicians1 etc41 & t a tax be plac$ ^u e w9d[ :i* _h %utt]s4 ,8 clos+ p>agraph 0 z foll[s3 ,= ! great b5efit ( ?is discov]y1 ?us freely communicat$ & be/[$ by me on ! public1 ,i dem& nei!r place1 p5sion1 exclusive privilege1 nor any o!r reg>d :atev]4 ,i expect only to h ! honor ( x4 ,& yet ,i "k !re are little1 envi\s m9ds :o w1 z usual1 d5y me ?is & say t my inv5tion 0 kn[n to ! anci5ts1 & p]haps !y may br+ passages out ( ! old books 9 pro( ( x4 ,i w n dispute ) ^! p t ! anci5ts knew n ! sun w\ld rise at c]ta9 h\rs2 !y possibly _h1 z we h1 almanacs t pr$ict$ x2 b x does n foll[ !nce t !y knew he gave light z soon z he rose4 ,t is :at ,i claim z my discov]y4 ,if ! anci5ts knew x1 x might h be5 long s9ce =gott52 = x c]ta9ly 0 unkn[n to ! mod]ns1 at lea/ to ! ,p>isians1 :i* to prove ,i ne$ use b "o pla9 simple argum5t4 ,!y are z well in/ruct$1 judici\s & prud5t a p z exi/ any:]e 9 ! _w1 all pr(ess+1 l myself1 to be lov]s ( economy1 &1 = ! _m heavy taxes requir$ f !m by ! necessities ( ! ,/ate h surely an abundant reason to be economical4 ,i say x is impossible t s s5sible a p1 "u su* circum/ances1 %\ld h liv$ s long by ! smoky1 un:olesome & enorm\sly exp5sive light ( c&les1 if !y _h really kn[n t !y might h _h z mu* pure light ( ! sun = no?+4 ,frankl9's amus+ lett] _h a s]i\s aim1 = 9 #aghd family exp5ses 7 mu* augm5t$ & adequate light+ by means ( c&les 0 v co/ly 9 ^? days4 ,h[ev]1 conditions h *ang$ enorm\sly 9 ! pa/ hundr$ & ?irty-five ye>s4 ,a great proportion ( ! population lives 9 ! d>k] cities4 ,! :eels ( progress mu/ be kept go+ cont9u\sly 9 ord] to curb ! co/ ( liv+1 :i* is con/antly m\nt+ high] ow+ to ! addition ( conv5i5ces & luxuries4 ,fur!rmore1 ! co/ ( light has s dim9i%$ t x is n only a m9or factor at pres5t b 9 _m cases is actually pay+ divid5ds 9 comm]ce & indu/ry4 ,x is pay+ divid5ds ( ano!r k9d 9 ! social & educational aspects ( ! home1 libr>y1 *ur*1 & art museum4 ,daylight sav+ has mu* to comm5d x1 b ! co/ ( daylight & ! value ( artificial light are important consid]ations4 ,! co/ ( fuels = light+ purposes _c be ?or\ghly comp>$ ?r\gh\t a span ( ye>s )\t reg>d to ! fluctuat+ pur*as+ p[] ( money1 :i* w\ld be too involv$ = consid]ation "h4 ,h[ev]1 x is int]e/+ to make a brief survey ?r\gh\t ! pa/ c5tury4 ,f #ahjj until #ahde :ale-oil sold = ab\t 4#hj p] gallon1 b aft] ?is p]iod x increas$ 9 value1 ow+ app>5tly to its gr[+ sc>city1 until x rea*$ a price ( #a4ge p] gallon 9 #ahee4 ,=tunately1 petroleum 0 discov]$ ab\t ?is "t1 s t ! oil-lamp did n become a luxury4 ,f #ahjj to #ahej tall[-c&les sold at approximately #bj c5ts a p\nd4 ,!re be+ six c&les to ! p\nd1 & inasmu* z ea* c&le burn$ ab\t sev5 h\rs1 ! light f a c&le co/ ab\t #a_/b c5t p] h\r4 ,f #ahej to #ahge tall[-c&les sold at an av]age price ( approximately #be c5ts a p\nd4 ,x may be int]e/+ to "k t a l>ge mat* emits ab\t z mu* light z a burn+ c&le & a s-call$ safety mat* ab\t "o ?ird z mu*4 ,a c&le-h\r is ! total am\nt ( light emitt$ by a /&>d c&le 9 "o h\r1 & c&le-h\rs 9 any case are obta9$ by multiply+ ! c&le-p[] ( ! s\rce by ! h\rs ( burn+4 ,9 a simil> mann]1 lum5s output multipli$ by h\rs ( op]ation give ! lum5-h\rs4 ,a /&>d c&le may be consid]$ to emit an am\nt ( light approximately equal to #aj lum5s4 ,a wax-c&le w emit ab\t z mu* light z a sp]m c&le b w consume ab\t #aj p] c5t4 less weight ( mat]ial4 ,a tall[ c&le w emit ab\t ! same am\nt ( light ) a consumption ab\t #ej p] c5t4 great]4 ,! tall[-c&le has disappe>$ f use4 ,) ! appe>ance ( k]os5e di/ill$ f petroleum ! camph5e lamp came into use4 ,! k]os5e co/ ab\t #hj c5ts p] gallon dur+ ! fir/ few ye>s ( its introduction4 ,! price ( k]os5e av]ag$ ab\t #ee c5ts a gallon betwe5 #ahfe & #ahge4 ,dur+ ! next decade x dropp$ to ab\t #bb c5ts a gallon & betwe5 #ahhe & #ahie x sold z l[ z #ac c5ts4 ,artificial gas 9 #ahfe sold approximately at #b4ej p] ?\s& cubic feet2 betwe5 #ahge & #ahhe at #b4jj2 betwe5 #ahhe & #ahie at #a4ej4 ,! comb9$ effect ( decreas+ co/ ( fuel or electrical en]gy = light-s\rces & ( ! great improvem5ts 9 light-production gave to ! h\sehold]1 = example1 a con/antly increas+ am\nt ( light = ! same exp5diture4 ,= example1 ! family :i* a c5tury ago sp5t two or ?ree h\rs 9 ! light ( a s+le c&le n[ enjoys _m times m light 9 ! same room = ! same price4 ,x is int]e/+ to trace ! influ5ce ( ?is greatly dim9i%+ co/ ( light 9 ! home4 ,= ! sake ( simplicity ! light ( a c&le w be reta9$ z ! unit & ! co/ ( light = ! home w be consid]$ to rema9 approximately ! same ?r\gh\t ! p]iod to be consid]$4 ,9 fact1 ! am\nt ( money t an av]age h\sehold] sp5ds = light+ has rema9$ fairly con/ant ?r\gh\t ! pa/ c5tury1 b he has enjoy$ a long] p]iod ( artificial light & a great] am\nt ( light z ! ye>s advanc$4 ,! foll[+ is a table ( approximate values :i* %[s ! light+ obta9able = #bj4jj p] ye> ?r\gh\t ! pa/ c5tury exclusive ( electricity3 ,h\rs ,equival5t ( ,c&le-h\rs ,ye> p] night light 9 c&les p] night p] ye> #ahjj #c #e #ae #e1ejj #ahej #c #h #bd #h1gjj #ahfj #c #aa #cc #ab1jjj #ahgj #c #bb #ff #bd1jjj #ahhj #c4e #cf #abf #df1jjj #ahij #d #ej #bjj #gc1jjj #aijj #e #aed #ggj #bhj1jjj ,x is se5 f ! =ego+ t 9 a c5tury ! c&le-equival5t obta9able = ! same co/ to ! h\sehold] increas$ at lea/ ?irty times1 :ile ! h\rs dur+ :i* ?is light is us$ h ne>ly d\bl$4 ,9 o!r words1 9 ! n9ete5? c5tury ! c&le-h\rs obta9able = #bj4jj p] ye> increas$ ab\t fifty times4 ,/at$ 9 ano!r mann]1 ! co/ ( light at ! end ( ! c5tury 0 ab\t "o fiftie? t ( c&le light at ! beg9n+ ( ! c5tury4 ,"o au?ority 9 comput+ ! exp5se ( light+ to ! h\sehold] 9 a l>ge city ( ?is c\ntry has /at$ t co9cid5t ) an increase ( #agjj p] c5t4 9 ! am\nt ( night light+ ( an ,am]ican family1 9 av]age circum/ances1 us+ gas = light1 !re has come a r$uction 9 ! co/ ( ! ye>'s light+ ( #cd p] c5t4 or approximately #g4ej p] ye>2 & t ! co/ ( light+ p] unit ( light--! c&le-h\r--is n[ b #b4h p] c5t4 ( :at x 0 9 ! fir/ half ( ! n9ete5? c5tury4 ,no o!r necessity ( h\sehold use has be5 s *eap5$ & improv$ dur+ ! la/ c5tury4 ,9 g5]al1 ! light-us] has tak5 advantage ( ! decrease by increas+ ! am\nt ( light us$ & ! p]iod dur+ :i* x is us$4 ,9 ?is mann] ! greatly dim9i%$ co/ ( light has be5 a m>k$ sociological & economic influ5ce4 ,aft] ,murdock made 8 fir/ in/allation ( gas-light+ 9 an indu/rial plant e>ly 9 ! n9ete5? c5tury1 he publi%$ a comp>ison ( ! exp5se ( op]ation ) t ( c&le-light+4 ,he arriv$ at ! co/s ( light equival5t to #ajjj c&le-h\rs z foll[s3 #ajjj c&le-h\rs ,gas-light+ at a rate ( two h\rs p] day #a4ie ?ree #a4dj ,c&le-light+ #f4ej ,x is se5 t ! long] h\rs ( burn+ r$uce ! co/ ( gas-light+ by r$uc+ ! p]c5tage ( ov]head *>ges4 ,!re are no su* factors 9 light+ by c&les because ! :ole in/allation is consum$4 ,?is is an e>ly example ( :i* an au!ntic record is available4 ,at ! pres5t "t a c]ta9 am\nt ( light obta9$ = #a4jj ) effici5t tung/5 filam5t lamps1 co/s #b4jj if obta9$ f k]os5e flames & ab\t #ej4jj if obta9$ by burn+ c&les4 ,9 ord] to obta9 ! co/ ( an equival5t am\nt ( light ?r\gh\t ! pa/ c5tury a great _m factors mu/ be consid]$4 ,obvi\sly1 ! results obta9$ by v>i\s p]sons w diff] ow+ to ! unavoidable factor ( judgm5t2 h[ev]1 ! foll[+ li/ ( approximate values w at lea/ indicate ! tr5d ( ! price ( light ?r\gh\t ! c5tury or m ( rapid developm5ts 9 light-production4 ,a fair av]age ( ! retail values ( fuels & ( electrical en]gy & an av]age lum9\s effici5cy ( ! light-s\rces involv$ h be5 us$ 9 mak+ ! computations4 ,! figures apply p>ticul>ly to ?is c\ntry4 ,,table ,,%[+ ,,! ,,approximate ,,total ,,co/ ,,( #ajjj ,,c&le-,,h\rs ,,= ,,v>i\s ,,p]iods ,p] #ajjj c&le-h\rs #ahjj to #ahej1 sp]m-oil #b4dj tall[ c&le #e4jj #ahej to #ahfe1 k]os5e #a4fe tall[ c&le #f4he #ahfe to #ahge1 k]os5e 4#ge tall[ c&le #f4be gas1 op5-flame 4#ij #ahge to #ahhe1 k]os5e 4#be gas1 op5-flame 4#fj #ahhe to #ahie1 k]os5e 4#ae gas1 op5-flame 4#dj #ahie to #aiae1 gas mantle 4#jg c>bon filam5t 4#ch metalliz$ filam5t 4#bh tung/5 filam5t 7vacuum7 4#ab tung/5 filam5t 7gas-fill$7 4#jg ,9 ^! days ! co/ ( liv+ has claim$ consid]able att5tion & x is int]e/+ to comp>e t ( light+4 ,9 ! foll[+ table ! price ( food & ( electric light+ are comp>$ = tw5ty ye>s prec$+ ! rec5t w>4 ,! great di/urbance due to ! w> is !reby elim9at$ f consid]ation1 b x %\ld be not$ t s9ce #aiad ! price ( food has greatly increas$ b t ( electric light+ has n *ang$ mat]ially4 ,! co/ ( ea* commodity is tak5 z "o hundr$ units = ! ye> #ahid b1 ( c\rse1 ! actual co/ ( liv+ = ! h\sehold] is p]haps a hundr$ times great] ?an ! co/ ( electric light+4 ,ye> ,food ,electric light+ #ahid #ajj #ajj #ahif #hj #ib #ahih #ib #ij #aijj #ajj #he #aijb #aac #gg #aijd #aaj #gg #aijf #aae #eg #aijh #abh #cj #aiaj #ach #bh #aiab #add #bc #aiad #ade #ag ,"o feature ( electric light+ :i* puzzles ! consum] & :i* gives ! politicians an opportunity = cry+ discrim9ation & inju/ice at ! public-s]vice company is ! great v>iation 9 rates4 ,!re is no discrim9ation or inju/ice :5 ! h\sehold]1 = example1 mu/ pay m = 8 light+ ?an a factory pays4 ,! rates are n only affect$ by dem& b by ! p]iod 9 :i* ! dem& comes4 ,resid5ce light+ is *iefly conf9$ to c]ta9 h\rs f #e to #i ,p4 ,m4 & !re is a great peak ( dem& at ?is "t4 ,! c5tral-/ations mu/ h equipm5t available = ?is %ort-"t dem& & mu* ( ! capacity ( ! equipm5t is unus$ dur+ ! rema9d] ( ! day4 ,! factory :i* uses electricity ?r\gh\t ! day or night or bo? is help+ to keep ! c5tral-/ation op]at+ effici5tly4 ,! equipm5t necess>y to supply electricity to ! factory is op]at+ long h\rs4 ,n only is ?is ov]head *>ge mu* less = factories & _m o!r consum]s ?an = ! h\sehold]1 b ! exp5se ( acc\nt+1 ( read+ met]s1 etc41 is ab\t ! same = all classes ( consum]s4 ,!re=e1 ?is is an appreciable item on ! bill ( ! small consum]4 ,d\btless1 ! public does n realize t ! enorm\s decrease 9 ! co/ ( light+ dur+ ! pa/ c5tury is due l>gely to ! fact t ! light+ indu/ry has gr[n l>ge4 ,increas$ production is responsible = "s ( ?is decrease & sci5ce = mu* ( x4 ,! latt]1 hav+ be5 call$ to ! aid ( ! manufactur]s1 :o are bett] able by virtue ( _! magnitude to sp5d "t & res\rces ^u sci5tific developm5ts1 has respond$ ) _m improvem5ts :i* h increas$ ! effici5cy ( light-production4 ,"s figures ( ! ,c5sus ,bureau may be ( int]e/4 ,^! are giv5 = #aiad 9 ord] t ! abnormal conditions due to ! rec5t w> may be avoid$4 ,! figures p]ta9+ to ! manufacture ( gas = sale :i* d n include private plants are z foll[s = ! ye> #aiad = ?is c\ntry3 ,numb] ( e/abli%m5ts #a1bhd ,capital #a1beb1dba1ehd ,value ( products 7gas1 coke1 t>1 etc47 #bbj1bcg1gij ,co/ ( mat]ials #gf1ggi1bhh ,value add$ by manufacture #adc1deh1ejb ,value ( gas #age1jfe1ibj ,coal us$ 7tons7 #f1aaf1fgb ,coke us$ 7tons7 #ifd1hea ,oil us$ 7gallons7 #gae1dah1fbc ,l5g? ( gas ma9s 7miles7 #eh1gbg ,manufactur$ products sold ,total gas 7cubic feet7 #bjc1fci1bfj1jjj ,/raight coal gas 7cubic feet7 #aj1eji1idf1jjj ,c>buret$ wat] gas 7cubic feet7 #ij1jag1gbe1jjj ,mix$ coal- & wat]-gas 7cubic feet7 #hf1bha1cci1jjj ,oil gas 7cubic feet7 #af1eab1bgd1jjj ,acetyl5e 7cubic feet7 #acf1efd1jjj ,o!r gas1 *iefly gasol5e 7cubic feet7 #aha1dab1jjj ,coke 7bu%els7 #aad1jia1gec ,t> 7gallons7 #abe1ich1fjg ,ammonia liquors 7gallons7 #ej1gcg1gfb ,ammonia1 sulphate 7p\nds7 #f1baf1fah ,( c\rse1 only a small fraction ( ! total gas manufactur$ is us$ = light+4 ,accord+ to ! ,u4 ,s4 ,geological ,survey1 ! quantities ( gas sold 9 ?is c\ntry 9 ! ye> #aiag 7 z foll[s3 ,coal-gas #db1ibg1gbh1jjj cubic feet ,wat]-gas #aec1deg1cah1jjj ,oil-gas #ad1gci1ejh1jjj ,byproduct gas #aca1jbf1ege1jjj ,natural gas #gie1aaj1cgf1jjj ,9 #aiad !re 7 #ch1gje1dif b>rels 7ea* fifty gallons7 ( illum9at+ oils ref9$ 9 ?is c\ntry & ! value 0 #if1hjf1deb4 ,ab\t half ( ?is quantity 0 export$4 ,9 #aiad ! value ( all c&les manufactur$ 9 ?is c\ntry 0 ab\t #b1jjj1jjj1 :i* 0 ab\t half t ( ! c&les manufactur$ 9 #aiji & 9 #aijd4 ,9 #aiad ! value ( ! mat*es manufactur$ 9 ?is c\ntry 0 #ab1eef1jjj4 ,?is has increas$ /eadily f #dbi1jjj 9 #ahdi4 ,9 #aiad ! glass indu/ries 9 ?is c\ntry made #g1jjj1jjj lamps1 #gj1jjj1jjj *imneys1 #af1cjj1jjj lant]n globes1 #bd1jjj1jjj %ades1 globes1 & o!r gas goods4 ,_m millions ( o!r light+ accessories 7 made1 b un=tunately !y are n classifi$4 ,"s figures p]ta9+ to public electric light & p[] /ations ( ! ,unit$ ,/ates = ! ye>s #aijg & #aiag are z foll[s3 #aiag #aijg ,numb] ( e/abli%m5ts #f1eda #d1gad ,comm]cial #d1bbd #c1dfb ,municipal #b1cag #a1efb ,income #ebf1hhf1djh #age1fdb1cch ,total horse-p[] ( plants #ab1heg1iih #d1jih1ahh ,/eam eng9es #h1chi1chi #b1fic1bgc ,int]nal combu/ion eng9es #bag1ahf #ee1hbh ,wat]-:eels #d1bea1dbc #a1cdi1jhg ,kil[att capacity ( g5]ators #i1jja1hgb #b1gji1bbe ,output 9 millions ( kil[att-h\rs #be1dch #e1hfc ,motors s]v$ 7horse-p[]7 #i1baf1cbc #a1fdi1jbf ,electric-arc /reet-lamps s]v$ #bef1hch 4444 ,electric-filam5t /reet-lamps s]v$ #a1chi1chb 4444 ,9 g5]al1 !re is a l>ge increase 9 ! v>i\s items dur+ ! decade repres5t$4 ,! output ( ! c5tral /ations d\bl$ 9 ! five ye>s f #aijg to #aiab1 & d\bl$ aga9 9 ! next five ye>s f #aiab to #aiag4 ,/reet lamps 7 n report$ 9 #aijg1 b 9 #aiab !re 7 #cdh1fdc arc-lamps s]v$ by ! public companies4 ,! numb] ( arc-lamps decreas$ to #bef1hch 9 #aiag4 ,on ! o!r h&1 !re 7 #fha1ieg electric filam5t /reet lamps s]v$ 9 #aiab1 :i* d\bl$ 9 numb] to #a1chi1chb 9 #aiag4 ,! co/ ( con/ruction & equipm5t ( ^! c5tral /ations total$ m ?an #c1jjj1jjj1jjj 9 #aiag4 ,al?\gh !re is no imm$iate prospect ( ! failure ( ! coal & oil supplies1 exhau/ion is surely approa*+4 ,& z ! supplies ( fuel = ! production ( gas & electricity dim9i%1 ! co/ ( light+ may advance4 ,! total am\nt ( oil available 9 ! kn[n oil-fields ( ?is c\ntry at ! pres5t "t has be5 e/imat$ by v>i\s exp]ts betwe5 #e1jjj1jjj1jjj & #bj1jjj1jjj1jjj b>rels1 ! be/ e/imate be+ ab\t #g1jjj1jjj1jjj4 ,! annual consumption is n[ ab\t #djj1jjj1jjj b>rels4 ,^! figures d n take into acc\nt ! oil :i* may be di/ill$ f ! ri* %ale deposits4 ,app>5tly ?is s\rce w yield a hundr$ billion b>rels ( oil4 ,9 a simil> mann] ! coal-supply is dim9i%+ & ! consumption is increas+4 ,9 #aiah m ?an a half-billion tons ( coal 7 %ipp$ f ! m9es4 ,! production ( natural gas p]haps has rea*$ its peak1 &1 ow+ to its relation to ! coal & oil deposits1 its supply is limit$4 ,al?\gh only a fraction ( ! total production ( gas1 oil1 & coal is us$ 9 light+1 ! limit$ supply ( ^! products emphasizes ! desirability ( develop+ ! enorm\s wat]-p[] res\rces ( ?is c\ntry4 ,! pres5t g5]ation w n be h>d press$ by ! dim9ution ( ! supply ( gas1 oil1 & coal1 b x c pr(it by enc\rag+ & ev5 dem&+ ! developm5t ( wat]-p[]4 ,fur!rmore1 x is an obligation to succe$+ g5]ations to h>ness ! riv]s & ev5 ! tides & waves 9 ord] t ! o!r res\rces w be cons]v$ z long z possible4 ,sci5ce w cont9ue to produce m effici5t light-s\rces1 b ! co/ ( light f9ally is dep5d5t ^u ! co/ ( ! en]gy suppli$ to ^! lamps4 ,at ! pres5t "t wat]-p[] is ! an*or to ! w9dw>d4 ,,xvii ,,light ,,& ,,safety ,x is e/abli%$ t outdoors life & prop]ty are at night saf] "u adequate light+ ?an !y are "u inadequate light+4 ,police dep>tm5ts 9 ! l>ge cities w te/ify t /reet-light+ is a p[]ful ally & t crime is fo/]$ by d>kness4 ,b 9 reckon+ ! co/ ( /reet-light+ to-day h[ _m take into acc\nt ! value ( safety to life & prop]ty & ! sav+ occasion$ by ! r$uction 9 ! police-=ce necess>y to patrol ! cities & t[ns8 ,ow+ to ! necessity ( d>k5+ ! /reets 9 ord] to r$uce ! haz>ds ( air-raids1 ,london exp]i5c$ a great increase 9 accid5ts on ! /reets1 :i* demon/rat$ ! practical value ( /reet-light+ f ! /&po9t ( accid5t prev5tion4 ,dur+ ! w>1 :5 da/>dly traitors & ag5ts ( ! enemy 7 /rik+ at indu/ry1 ! value ( light+ 0 fur!r recogniz$ by ! indu/ries1 ) ! result t flood-light+ 0 in/all$ to protect !m4 ,by common cons5t ?is new phase 0 t]m$ protective light+4 ,soon aft] ! entrance ( ?is c\ntry into ! rec5t w>1 ! ,u4 ,s4 ,milit>y ,intellig5ce e/abli%$ a ,section ( ,plant ,protection :i* _h ?irty-?ree di/rict (fices dur+ ! w> & gave att5tion to ?irty-five ?\s& indu/rial plants engag$ 9 production ( w> mat]ials4 ,protective light+ 0 e>ly recogniz$ by ?is section z a v pot5tial ag5cy = def5se1 & ext5sive use 0 made ( x4 ,= example1 ,edmund ,leigh1 *ief ( ! section1 9 discuss+ ! value ( outdoor light+ /at$3 ,an illu/ration ( our "w 9 ?is connection is ! case ( an #hj1jjj1jjj p[d] plant ( rec5t con/ruction4 ,we arrang$ to h all wires buri$4 ,9 addition to ! ord9>y light+ on an adjac5t hill !re is a l>ge se>*light :i* w comm& any "p ( ! build+s & gr\nds4 ,e ?ree hundr$ y>ds !re is a wat*-t[] ) a se>*light on top4 ,^! se>*lights are = use only 9 em]g5cy4 ,ea* t[] has a telephone s]vice1 "o connect$ ) ! o!r4 ,! m5 9 ! t[]s h a view ( ! build+ ext]iors1 :i* are all well light$1 & ! m5 9 ! build+s look across ! y>d to ! light$ f5ce l9e & s get a silh\ette ( p]sons or objects 9 betwe54 ,! mo/ vital p>ts ( ! build+s are surr\nd$ by ?ree f5ces4 ,9 ! ne>-by woods ! und]bru% has be5 cle>$ out & de/roy$4 ,! trunks & limbs ( trees h be5 :itewa%$4 ,no "o c walk among ^! trees or betwe5 ! trees & ! plant )\t be+ se5 9 silh\ette4444 ,i say flatly t ,i "k no?+ t is s pot5tial = good def5se z good illum9ation & at ! same "t s little und]/ood4 ,)\t su* protective light+ an army ( m5 w\ld h be5 requir$ to insure ! safety ( ?is "o vital plant2 /ill x is obvi\s t ! co/ ( ! protective light+ 0 an insignificant "p ( ! value ( ! plant :i* x insur$ aga9/ damage & de/ruction4 ,! ,unit$ ,/ates p>ticipat$ = n9ete5 mon?s 9 ! rec5t w> & dur+ t "t ab\t #djj1jjj casualties 7 suff]$ by its =ces4 ,?is 0 at ! rate ( ab\t #bej1jjj p] ye>1 :i* includ$ casualties 9 battle1 at sea1 & f sickness1 w\nds1 & accid5ts4 ,e "o has felt ! magnitude ( ?is rate ( casualties because ei!r 8 home or t ( a fri5d 0 blight$ by "o or m ( ^! trag$ies 9 ! n9ete5 mon?s4 ,h[ev]1 ,r4 ,e4 ,simpson ( ! ,travel]s ,insurance ,company has /at$ t3 ,dur+ a "o-ye> p]iod 9 ?is c\ntry ! numb] ( accid5ts due to inadequate or improp] light+ exce$s ! ye>ly rate ( our w> casualties4 ,?is is a />tl+ comp>ison1 :i* emphasizes a phase ( light+ t has long be5 recogniz$ by exp]ts b has be5 g5]ally ignor$ by ! indu/ries & by ! public4 ,! condition d\btless is due l>gely to a lag 9 ! prop] utilization ( artificial light+ beh9d ! rapid increase 9 conge/ion 9 ! indu/ries & 9 public places4 ,accid5t prev5tion is an important phase ( mod]n life :i* mu/ receive m att5tion4 ,f publi%$ /ati/ics & cons]vative e/imates x has be5 conclud$ t !re are approximately #be1jjj p]sons kill$ or p]man5tly disabl$1 #ejj1jjj s]i\sly injur$1 & #a1jjj1jjj slightly injur$ ea* ye> 9 ?is c\ntry4 ,translat+ ^! figures by means ( ! accid5t sev]ity rates1 ,mr4 ,simpson has f\nd t !re is a total ( #ahj1jjj1jjj days ( "t lo/ p] ye>4 ,?is is equival5t to ! loss ( s]vices ( #fjj1jjj m5 = a full ye> ( #cjj "w-days4 ,?is loss is di/ribut$ ov] ! entire c\ntry & consequ5tly its magnitude is n demon/rat$ except+ by /ati/ics4 ,( c\rse1 ! causes ( ! accid5ts are num]\s1 b1 among ! means ( prev5tion1 prop] light+ is important4 ,accord+ to "s au?orities at lea/ #ah p] c5t4 ( ^! accid5ts are due to defects 9 light+4 ,on ?is basis ! s]vices ( #ajh1jjj m5 z produc]s & wage-e>n]s are cont9ually lo/ at ! pres5t "t because ! light+ is n suffici5t or prop] = ! safety ( work]s4 ,if ! full ye>'s labor ( #ajh1jjj m5 c\ld be appli$ to ! m9+ ( coal1 #acj1jjj1jjj million tons ( coal w\ld be add$ to ! ye>ly output2 & only #aj1jjj tons w\ld be necess>y to supply adequate light+ = ?is army ( m5 work+ = a full ye> = t5 h\rs ea* day4 ,/ati/ics obta9$ "u ! ,briti% workm5's comp5sation sy/em %[ t #be p] c5t4 ( ! accid5ts 7 caus$ by inadequate light+ ( indu/rial plants4 ,mu* has be5 said & actually done reg>d+ ! sav+ ( fuel by curtail+ light+1 b ! sav+ may easily be conv]t$ into a great loss4 ,= example1 a #be-watt electric lamp may be op]at$ t5 h\rs a day = a :ole ye> at ! exp5se ( "o eigh? ( a ton ( coal4 ,suppose ?is lamp to be ov] a /airway or at any vital po9t & t by ext+ui%+ x !re occurs a s+le accid5t :i* involves ! loss ( only "o day's "w on ! "p ( ! work]4 ,if ?is "o day's "t c\ld h produc$ coal1 !re w\ld h be5 en\gh coal m9$ 9 ! t5 h\rs to op]ate ! lamp = ?irty-two ye>s4 ,! insignificant co/ ( light+ is also %[n by ! di/ribution ( ! consumption ( fuel = heat+1 cook+1 & light+ 9 ! home4 ,( ! total am\nt ( fuel consum$ 9 ! home = ^! purposes1 #hg p] c5t4 is = heat+1 #aa p] c5t4 = cook+ & #b p] c5t4 = light+4 ,! am\nt ( coal us$ = light+ purposes 9 g5]al is ab\t #b4e p] c5t4 ( ! total consumption ( coal1 s x is se5 t ! curtailm5t ( light+ at be/ _c save mu* fuel2 & x may actually result 9 a great economic loss4 ,by replac+ ineffici5t lamps & accessories ) effici5t light+-equipm5t & by wa%+ w9d[s & artificial light+ devices1 a real sav+ c be realiz$4 ,improp] light+ may be z productive ( accid5ts z inadequate light+1 & ?r\gh\t ! indu/ries & ^u ! /reets ! misuse ( light is 9 evid5ce4 ,! bl9d+ effect ( a brilliant light-s\rce is easily prov$ by look+ at ! sun4 ,aft] a few mom5ts great discom=t is exp]i5c$1 & on look+ away f ?is brilliant s\rce ! eyes are tempor>ily bl9d$ by ! aft]-images4 ,:5 ?is happ5s 9 a factory z ! result ( gaz+ into an un%ield$ light-s\rce1 ! workman may be injur$ by mov+ ma*9]y1 by /umbl+ ov] objects1 & 9 _m o!r ways4 ,un%ad$ light-s\rces are too preval5t 9 ! indu/ries4 ,improp] light+ is likely to cause deep %ad[s :]e9 _m dang]s may be hidd54 ,on ! /reet ! gl>e f automobile head-lamps is v preval5t & ne>ly ev]ybody may te/ify f exp]i5ce to ! dang]s ( gl>e4 ,ev5 ! gl>+ locomotive head-lamp has be5 responsible = _m casualties4 ,un=tunately1 natural light+ outdoors has n be5 "u ! control ( man & he has accept$ x z x is4 ,! sky is a h>mless s\rce ( light :5 view$ outdoors & ! sun is 9 su* a position t x is usually easy to avoid look+ at x4 ,x is s int5sely gl>+ t man unconsci\sly avoids look+ directly at x4 ,^! conditions are responsible to an ext5t = man's indiff]5ce & ev5 ignorance ( ! rudim5ts ( safe light+4 ,:5 he has artificial light1 ov] :i* he may ex]cise control1 he ei!r ignores x or ow+ to ! less /rik+ gl>e he misuses x & 8 eyesight )\t realiz+ x4 ,a great deal ( eye-/ra9 & p]man5t eye tr\ble arises f ! abuse ( ! eyes by improp] light+4 ,= example1 ne>-sight$ness is (t5 due to inadequate illum9ation1 :i* makes x necess>y = ! eyes to be ne> ! "w or ! read+-page4 ,improp] or inadequate light+ especially influ5ces eyes t are immature 9 gr[? & 9 function1 & x has be5 %[n t ) improvem5ts 9 light+ ! p]c5tage ( %ort-sight$ness has decreas$ 9 ! s*ools4 ,fur!rmore1 x has be5 %[n t :]e no p>ticul> att5tion has be5 giv5 to light+ & vision1 ! p]c5tage ( %ort-sight$ness has increas$ ) ! grade4 ,!re are tw5ty million s*ool *ildr5 9 ?is c\ntry ^: future eyesight is 9 ! h&s ( ^? :o h jurisdiction ov] light+ & vision4 ,!re are m ?an a hundr$ million p]sons 9 ?is c\ntry ^: eyes are daily subject$ to improp] light+-conditions1 ei!r ?r\gh _! own indiff]5ce or ?r\gh ! neglig5ce ( o!rs4 ,( a c]ta9 gr\p ( #ia1jjj purely indu/rial accid5ts 9 ! ye> #aiaj1 ,mr4 ,simpson has /at$ t #bc4h p] c5t4 7 due1 directly or indirectly1 to ! lack ( prop] illum9ation4 ,^! may be fur!r divid$ into two approximately equal gr\ps1 "o ( :i* comprises ! accid5ts due to inadequate illum9ation & ! o!r to ^? t[>d :i* improp] light+ 0 a contribut+ cause4 ,! seasonal v>iation ( ^! accid5ts is giv5 9 ! foll[+ table1 bo? = ^? due directly or indirectly to inadequate & improp] light+ & ^? due to o!r causes4 ,,seasonal ,,di/ribution ,,( ,,indu/rial ,,accid5ts ,,due ,,to ,,light+ ,,conditions ,,& ,,to ,,o!r ,,causes ,p]c5tage due to ,light+ conditions ,o!r causes ,july #d4h #e4i ,augu/ #e4b #f4b ,septemb] #f4a #f4i ,octob] #h4f #h4e ,novemb] #aj4i #aj4e ,decemb] #ae4f #ab4b ,janu>y #af4a #aa4i ,febru>y #aj4j #aj4e ,m>* #g4f #h4h ,april #f4a #f4i ,may #e4b #e4h ,june #c4h #e4i ,! figures 9 "o column h no direct relation to ^? 9 ! o!r2 t is1 ea* column mu/ be consid]$ by itself4 ,x is se5 f ! =ego+ t ab\t half ! numb] ( ! accid5ts due to poor illum9ation occurr$ 9 ! mon?s ( ,novemb]1 ,decemb]1 ,janu>y1 & ,febru>y4 ,^! are ! mon?s ( inadequate illum9ation unless artificial light+ has be5 giv5 special att5tion4 ,! same g5]al type ( seasonal di/ribution ( accid5ts due to o!r causes is se5 to exi/ b n s prom95tly4 ,! greate/ mon?ly rate ( accid5ts dur+ ! w9t] season is ne>ly f\r times ! m9imum mon?ly rate dur+ ! summ] = ^? accid5ts due to light+ conditions4 ,?is ratio r$uces to ab\t twice 9 ! case ( accid5ts due to o!r causes4 ,look+ at ! data f ano!r angle1 x may be consid]$ t ! likelihood ( an accid5t be+ caus$ by light+ conditions is ab\t twice z great 9 any ( ! f\r w9t] mon?s z 9 any ( ! rema9+ eight mon?s4 ,d\btless1 ?is may be expla9$ l>gely ^u ! basis ( morale4 ,! w9t] mon?s are m dre>y ?an ^? ( summ] & ! workman's g5]al outlook is diff]5t 9 w9t] ?an 9 summ]4 ,9 ! =m] season he goes back & =? to "w 9 ! d>k1 or at be/1 9 ! cold twilight4 ,he is n only m depress$ b he is clumsi] 9 8 heavi] clo?+4 ,if ! en]vat+ influ5ce ( ^! factors is comb9$ ) a great] clums9ess due to cold & p]haps to colds1 x is n difficult to acc\nt = ?is type ( seasonal di/ribution ( accid5ts4 ,a /udy ( ! accid5ts ( #aiag indicat$ t #ac p] c5t4 occurr$ betwe5 #e & #f ,p4 ,m4 :5 artificial light+ is g5]ally 9 use to help out ! fail+ daylight4 ,only #g4c p] c5t4 occurr$ betwe5 #ab ,m4 & #a ,p4 ,m4 ,illu/ration3 ,,signal-,,light ,,= ,,airplane ,illu/ration3 ,,tr5* ,,light-,,signal+ ,,outfit ,illu/ration3 ,,aviation ,,field ,,light-,,signal ,,projector ,illu/ration3 ,,signal ,,se>*-,,light ,,= ,,airplane ,illu/ration3 ,,unsafe1 ,,unproductive ,,light+ ,,wor?y ,,( ,,! ,,d>k ,,ages ,illu/ration3 ,,! ,,same ,,factory ,,made ,,safe1 ,,*e]ful1 ,,& ,,m ,,productive ,,by ,,mod]n ,,light+ ,!re is ano!r aspect ( ! subject :i* deals p>ticul>ly ) ! safety ( ! light-s\rce or me?od ( light+4 ,z ea* innovation 9 light+ appe>$ dur+ ! pa/ c5tury !re imm$iately arose ! "q ( safety4 ,! fire-haz>d ( op5 flames receiv$ att5tion 9 e>ly days1 & :5 gas-light+ appe>$ x 0 condemn$ z a poison & an explosive4 ,m9]al-oil lamps introduc$ ! dang] ( explosions ( ! vapors produc$ by evaporation4 ,:5 electric light+ appe>$ x 0 inve/igat$ ?or\ghly4 ,! result ( all ?is has be5 an ef=t to make lamps & me?ods safe4 ,insurance companies h ! relative safety ( ^! sy/ems e/abli%$ to _! satisfaction & to-day little fire-haz>d is atta*$ to ! pres5t modes ( g5]al light+ if prop] precautions h be5 tak54 ,:5 electric light+ 0 fir/ introduc$ ! public look$ ^u electricity z dang]\s & naturally _m que/ions p]ta9+ to haz>ds arose4 ,! di/ribution ( electricity has be5 s highly p]fect$ t little is he>d ( ! haz>ds :i* 7 s magnifi$ 9 ! e>ly ye>s4 ,data ga!r$ betwe5 #ahhd & #ahhi %[$ t ab\t #ac1jjj fires took place 9 a c]ta9 di/rict4 ,( ^!1 #db 7 attribut$ to electric wires2 #bb times z _m to breakage & explosion ( k]os5e lamps2 & t5 times z _m ?r\gh c>elessness ) mat*es4 ,^! figures _c be tak5 at _! face value because ( ! abs5ce ( data %[+ ! relative am\nt ( electric & k]os5e light+2 nev]!less !y are int]e/+ because !y repres5t ! e>ly p]iod4 ,!re are indu/ries :]e unusual c>e mu/ be ex]cis$ 9 reg>d to ! light+4 ,9 c]ta9 *emical indu/ries no lamps are us$ except+ ! inc&esc5t lamp & ?is is enclos$ 9 an air-tight glass globe4 ,ev5 a public-s]vice gas company cautions its employees & patrons ?us3 ,d n look = a gas-leak ) a nak$ light6 ,use electric light4 ,! coal-m9e (f]s an int]e/+ example ( ! precautions necess>y because ! same type ( problems are f\nd 9 x z 9 indu/ries 9 g5]al1 ) ! additional difficulties att5d+ ! pres5ce or possible pres5ce ( explosive gas4 ,! surr\nd+s 9 a coal-m9e reflect a small p]c5tage ( ! light1 s t mu* light is wa/$ unless ! walls are :itewa%$4 ,?is is a practical me?od = increas+ safety 9 coal-m9es4 ,h[ev]1 ! mo/ dang]\s feature is ! light-s\rce itself4 ,accord+ to ! ,bureau ( ,m9es dur+ ! ye>s #aiaf & #aiag ab\t #fj p] c5t4 ( ! fatalities due to gas & coal-du/ explosions 7 directly traceable to ! use ( defective safety lamps & to op5 flames4 ,9 ! e>ly days ( coal-m9+ x 0 f\nd t ! flame ( a c&le occasionally caus$ explosions 9 ! m9es4 ,x 0 also f\nd t sp>ks ( fl9t & /eel w\ld n readily ignite ! gas or coal-du/ & ?is primitive device 0 us$ z a light-s\rce4 ,( c\rse1 /ati/ics are unavailable conc]n+ ! casualties 9 coal-m9es ?r\gh\t ! pa/ c5turies1 b ) ! accid5ts n uncommon 9 ?is sci5tific age1 ) its elaborate organizations /riv+ to /amp out su* casualties1 !re is good reason to believe t previ\s to a c5tury or two ago ! risks ( coal-m9+ mu/ h be5 great4 ,op5 flames h be5 widely us$ 9 ?is indu/ry1 b !re has always be5 ! risk ( ! pres5ce or ! appe>ance ( gas or explosive du/4 ,! e>ly op5-flame lamps n only 7 s\rces ( dang] b _! feeble v>y+ int5sity caus$ s]i\s damage to ! eyesight ( m9]s4 ,?is factor is always pres5t 9 inadequate & improp] light+1 b its influ5ce is noticeable 9 coal-m9+ 9 ! n]v\s disease affect+ ! eyes :i* is kn[n z ny/agmus4 ,! symptoms ( ! disease are inability to see at night & ! dazzl+ effect ( ord9>y lamps4 ,f9ally objects appe> to ! suff]] to dance ab\t & 8 vision is g5]ally v mu* di/urb$4 ,! oil-lamps us$ 9 coal-m9+ h a lum9\s int5sity equival5t to ab\t "o to f\r c&les1 b ow+ to ! atmosph]ic conditions 9 ! m9es a flame does n burn z brightly z 9 ! fre% air4 ,! possibility ( explosion due to ! op5 flame 0 elim9at$ by surr\nd+ x ) a metal gauze4 ,davy 0 ! inv5tor ( ?is device & 8 safety lamp introduc$ ab\t a hundr$ ye>s ago has be5 a boon to ! coal-m9]4 ,v>i\s improvem5ts h be5 devis$1 b ,davy's lamp conta9$ ! ess5tials ( a safety device4 ,! flame is surr\nd$ by a cyl9d] ( metal gauze :i* by =m+ a mu* cool] b\nd>y prev5ts ! m9e-gas f becom+ heat$ locally by ! lamp flame to a suffici5t temp]ature to ignite & consequ5tly to explode4 ,?is device n only keeps ! flame f ignit+ ! gas b x also s]ves z an indicator ( ! am\nt ( gas pres5t1 by ! v>iation 9 ! size & appe>ance ( ! tip ( ! flame4 ,h[ev]1 ! gauze r$uces ! lum9\s output1 & z x accumulates soot & du/ ! light is greatly dim9i%$4 ,"o ( ^! lamps is ab\t z lum9\s z a c&le1 initially1 b its int5sity is (t5 r$uc$ by accumulations ^u ! gauze to only "o fif? ( ! initial value4 ,! acetyl5e lamp is ! be/ op5-flame light-s\rce available to ! m9]1 = sev]al reasons4 ,x is ( a high] c&le-p[] ?an ! o!rs & z x is a burn+ gas1 !re is n ! dang] ( fly+ sp>ks z 9 ! case ( burn+ wicks4 ,! great] int5sity ( illum9ation af=ds a great] safety to ! m9] by enabl+ him to detect loose rock :i* may be ready to fall ^u him4 ,h[ev]1 ?is lamp may be a s\rce ( dang]1 ow+ to ! fact t x w burn m brilliantly 9 a vitiat$ atmosph]e ?an o!r flame-lamps4 ,ano!r disadvantage is ! possibility ( calcium c>bide accid5tally spilt com+ 9 contact ) wat] & !reby caus+ ! g5]ation ( acetyl5e gas4 ,if ?is is produc$ 9 ! m9e 9 suffici5t quantities x is a dang] :i* may n be suspect$4 ,if ignit$ x w explode & may also cause sev]e burns4 ,! electric lamp1 be+ an enclos$ light-s\rce capable ( be+ subdivid$ & f$ by a small portable batt]y1 e>ly gave promise ( solv+ ! problem ( a safe m9e-lamp ( adequate c&le-p[]4 ,mu* +5uity has be5 appli$ to ! developm5t ( a portable electric safety m9e-lamp1 & sev]al su* lamps are n[ approv$ by ! ,bureau ( ,m9es4 ,two g5]al types are be+ manufactur$1 ! cap outfit & ! h& outfit4 ,!y consi/ ess5tially ( a lamp 9 a reflector ^: ap]ture is clos$ ) a %eet or a l5s ( cle> glass4 ,! batt]y may be ( ! dry or /orage type & 9 ! case ( ! cap outfit ! batt]y is c>ri$ on ! back4 ,! specifications = ^! lamps dem& t a lum9\s int5sity av]ag+ at lea/ #j4d c&le be ma9ta9$ ?r\gh\t twelve consecutive h\rs ( op]ation4 ,at no "t dur+ ?is p]iod %all ! output ( light fall bel[ #a4be lum5s = a cap-lamp & bel[ #c lum5s = a h&-lamp4 ,inasmu* z ^! are equipp$ ) reflectors1 ! specifications insi/ t a circle ( light at lea/ sev5 feet 9 diamet] %all be ca/ on a wall tw5ty in*es away4 ,x appe>s t a portable lamp is an economic necessity 9 ! coal-m9es1 on acc\nt ( ! exp5se1 inconv5i5ce1 & possible dang]s introduc$ by di/ribution sy/ems su* z are us$ 9 mo/ places4 ,al?\gh ! major defects 9 light+ are due to abs5ce ( light 9 dang]\s places1 to gl>e1 & to o!r factors ( improp] light+1 !re are _m m9or details :i* may contribute to safety4 ,= example1 l[ lamps are useful 9 mak+ /eps 9 !at]s & 9 o!r places1 9 draw+ att5tion to entrances ( elevators1 9 light+ ! aisles ( ,pullman c>s1 "u h&-rails on /airways1 & 9 _m o!r vital places4 ,a /udy ( accid5ts indicates t simple exp$i5ts are effective prev5tives4 ,,xviii ,,! ,,co/ ,,( ,,liv+ ,a comp>ison ( ! civilization ( ! pres5t ) t ( a c5tury ago reveals a />tl+ diff]5ce 9 ! /&>ds ( liv+4 ,to-day mank9d enjoys conv5i5ces & luxuries t 7 undream$ ( by ! pa/ g5]ations4 ,= example1 a c]ta9 t[n 9 ,i[a1 a score ( ye>s ago1 0 apprais$ = a bond-issue & x 0 necess>y to ext5d its limits consid]ably 9 ord] to include a valuation ( "o half million doll>s requir$ by ! und]writ]s4 ,on a summ]'s ev5+ at ! pres5t "t a ?\s& pleasure automobiles may be f\nd p>k$ along its /reets & ^! exce$ 9 valuation t ( ! entire t[n only tw5ty ye>s ago & equal x to-day4 ,!re are economi/s :o w\ld argue t ! automobile has paid = itself by its usefulness1 b ! fact /ill exi/s t a great am\nt ( labor has be5 div]t$ f produc+ food1 clo?+1 & fuel to ! production ( pleasure automobiles4 ,& ?is is ! case ) _m o!r conv5i5ces & luxuries4 ,x is admitt$ t mank9d des]ves ^! ref9em5ts ( mod]n civilization1 b he mu/ expect ! co/ ( liv+ to increase unless c\nt]act+ measures are tak54 ,! economics ( ! increas+ co/ ( liv+ & ! analysis ( ! relations ( necessities1 conv5i5ces1 & luxuries are too complex to be ?or\ghly discuss$ "h4 ,9 fact1 ! mo/ exp]t economi/s w\ld disagree on _m po9ts4 ,h[ev]1 x is c]ta9 t ! co/ ( liv+ has /eadily increas$ dur+ ! pa/ c5tury & x is reasonably c]ta9 t ! /&>ds ( ! pres5t civilization are responsible = "s if n all ( ! increase4 ,increas$ production is an an*or to ! w9dw>d4 ,x may drag & give way to "s ext5t1 b x w always oppose ! c\rse ( ! co/ ( liv+4 ,:5 ! fir/ indu/rial plant 0 light$ by gas1 e>ly 9 ! n9ete5? c5tury1 ! aim 0 m]ely to re9=ce daylight t[>d ! end ( ! day4 ,cont9u\s op]ation ( indu/rial plants 0 n practis$ 9 ^? days1 except+ 9 a v few cases :]e x 0 ess5tial4 ,to-day "s indu/ries op]ate cont9u\sly1 b mo/ ( !m d n4 ,9 ! latt] case ! consum] pays m = ! product because ! p]c5tage ( fix$ or ov]head *>ge is great]4 ,inve/m5t 9 gr\nd1 build+s1 & equipm5t exacts its toll cont9u\sly & x is obvi\s t ?ree successive %ifts produc+ ?ree times z mu* z a s+le day %ift1 or z mu* z a trebl$ day %ift1 w produce ! less co/ly product4 ,9 ! =m] case ! fix$ *>ge is di/ribut$ ov] ! production ( cont9u\s op]ation1 b 9 ! latt] case ! production ( a s+le day %ift assumes ! entire burd54 ,( c\rse1 !re are _m factors :i* ent] into su* a consid]ation & an important "o is ! desirability ( work+ at night4 ,x is n ! int5tion to t\* ^u ! psy*ological & sociological aspects b m]ely to look coldly ^u ! facts p]ta9+ to artificial light & production4 ,9 ! fir/ place1 x has be5 prov$ t 9 factories prop] light+ z obta9$ by artificial means is g5]ally m satisfactory ?an ! natural light+4 ,( c\rse1 a n>r[ build+ ) w9d[s on two sides or a "o-/ory build+ ) a saw-too? ro( ( be/ design may be adequately illum9at$ by natural light1 b ^! build+s are ! exception & !y w gr[ r>] z indu/rial di/ricts become m conge/$4 ,artificial light may be controll$ s t light ( a satisfactory quality is prop]ly direct$ & diffus$4 ,suffici5t int5sities ( illum9ation may be obta9$ & ! failure ( artificial light is a remote possibility z comp>$ ) ! daily failure ( natural light4 ,) increas+ co/ ( gr\nd space1 factories are built ( sev]al /ories & ) less space giv5 to light c\rts1 ) ! result t ! ratio ( w9d[ area to t ( ! floor is r$uc$4 ,^! t5d5cies militate aga9/ satisfactory daylight+4 ,9 ! smoky conge/$ indu/rial di/ricts ! p]iod ( effective daylight is gradually dim9i%+ & artificial light+ is always ess5tial at lea/ z a re9=cem5t = daylight4 ,x has be5 prov$ t prop] artificial light+--& !re is no excuse = improp] artificial light+--is sup]ior to mo/ int]ior daylight+ conditions4 ,illu/ration3 ,,locomotive ,,electric ,,headlight ,illu/ration3 ,,se>*-,,light ,,on ,a ,,fire-,,boat ,illu/ration3 ,,build+ ,,%ips ,,"u ,,artificial ,,light ,,at ,,hog ,,isl& ,,%ipy>d ,al?\gh x is difficult to pres5t figures 9 a brief discussion ( ?is "*1 x may be /at$ t1 9 g5]al1 ! co/ ( adequate artificial light is ab\t #b p] c5t4 ( ! pay-roll ( ! work]s2 ab\t #aj p] c5t4 ( ! r5tal *>ges2 & only a fraction ( #a p] c5t4 ( ! co/ ( ! manufactur$ products4 ,^! figures v>y consid]ably1 b !y repres5t cons]vative av]age e/imates4 ,f ^! x is se5 t artificial light+ is a small factor 9 add+ to ! co/ ( ! product4 ,b does artificial light+ add to ! co/ ( a product8 ,_m examples c\ld be cit$ to prove t prop] artificial light+ may be responsible = an actual r$uction 9 ! co/ ( ! product4 ,9 a c]ta9 plant x 0 det]m9$ t ! workm5 ea* lo/ an appreciable "p ( an h\r p] day because ( inadequate light+4 ,a prop]ly design$ & ma9ta9$ light+-sy/em 0 in/all$ & ! sav+ 9 ! wages previ\sly lo/1 m ?an cov]$ ! op]at+-exp5se ( ! artificial light+4 ,besides really co/+ ! manufactur] less ?an no?+1 ! new artificial light+ sy/em 0 responsible = bett] products1 decreas$ spoilage1 m9imiz$ accid5ts1 & g5]ally elevat$ spirits ( ! workm54 ,9 "s cases x is only necess>y to save "o m9ute p] h\r p] workman to (fset entirely ! co/ ( light+4 ,! =ego+ & _m o!r examples illu/rate ! insignificance ( ! co/ ( light+4 ,! effectiv5ess ( artificial light+ 9 r$uc+ ! co/ ( liv+ is easily demon/rat$ by comp>+ ! output ( a factory op]at+ on "o & two %ifts p] day respectively4 ,9 a well-light$ factory :i* op]at$ day & night %ifts1 ! co/ ( adequate light+ 0 #g c5ts p] squ>e foot p] ye>4 ,if ?is factory1 op]at+ only 9 ! daytime1 7 to ma9ta9 ! same output1 x w\ld be necess>y to d\ble its size4 ,9 ord] to %[ ! economic value ( artificial light+ x is only necess>y to comp>e ! co/ ( light+ ) ! r5tal *>ge ( ! addition & ( its equipm5t4 ,a fair r5tal value = plant & equipm5t is #ej c5ts p] squ>e foot p] ye>2 b ( c\rse ?is v>ies consid]ably1 dep5d+ ^u ! type ( plant & ! "* ( ! equipm5t4 ,an inve/igation %[$ t ?is value v>ies usually betwe5 #cj to #gj c5ts p] squ>e foot p] ye>4 ,us+ ! mean value1 #ej c5ts1 x is se5 t ! r5tal *>ge is ab\t sev5 times ! co/ ( light+4 ,fur!rmore1 !re is a sav+ ( #dc c5ts p] squ>e foot p] ye> dur+ ! night op]ation by op]at+ ! night %ift4 ,( c\rse1 ?is is n /rictly true because a depreciation ( ma*9]y dur+ ! night %ift %\ld be all[$ =4 ,^! fix$ *>ges w\ld av]age slightly m ?an half z mu* 9 ! case ( ! two-%ift factory z 9 ! case ( ! same output f a factory twice z l>ge b op]at+ only a day %ift4 ,incid5tally1 ! two-%ift factory ne$ n be a h>d%ip = ! work]s1 =1 if ! eight-h\r %ifts are prop]ly arrang$1 ! work] on ! night %ift may be 9 b$ by midnight & ! objection to a di/urbance ( ord9>y h\rs ( sleep is virtually elim9at$4 ,9 a discussion ( light & safety pres5t$ 9 ano!r *apt] ! />tl+ indu/rial losses due to accid5ts are %[n to be due p>tially to inadequate or improp] light+4 ,ab\t "o f\r? ( ! total numb] ( accid5ts may be *>g$ to defective light+4 ,! consum] be>s ! burd5 ( ! support ( an unproduc+ army ( idle m54 ,accord+ to "s exp]ts an av]age ( ab\t #aej1jjj m5 are cont9u\sly idle 9 ?is c\ntry ow+ to inadequate & improp] light+4 ,?is is an appreciable factor 9 ! co/ ( liv+1 b ! greate/ effectiv5ess ( artificial light+ 9 curtail+ co/s is to be f\nd 9 r$uc+ ! fix$ *>ges borne by ! product ?r\gh ! op]ation ( two %ifts & by directly increas+ production ow+ to improv$ light+4 ,! /&>d ( artificial-light+ int5sity possess$ by ! av]age p]son at ! pres5t "t is an inh]itance f ! pa/4 ,9 ^? days :5 artificial light 0 mu* m co/ly ?an at pres5t ! t5d5cy naturally 0 to use j z little light z necess>y4 ,t attitude c\ld n h be5 sev]ely criticiz$ 9 ^? e>ly days ( artificial light+1 b x is inexcusable to-day4 ,eyesight & great] safety f accid5ts are 9 !mselves valuable en\gh to w>rant adequate light+1 b besides ^! !re is ! appeal ( increas$ production4 ,outdoors on a cle> summ] day at noon ! int5sity ( daylight illum9ation at ! e>?'s surface is ab\t #aj1jjj foot-c&les2 9 o!r words1 x is equal to ! illum9ation on a surface produc$ by a light-s\rce equival5t to #aj1jjj c&les at a di/ance ( "o foot f ! surface4 ,?is w be recogniz$ z an enorm\s int5sity ( illum9ation4 ,on a cl\dy day ! int5sity ( illum9ation at ! e>?'s surface may be z high z #cjjj foot-c&les & on a gloomy day ! illum9ation at ! e>?'s surface may be #ajjj foot-c&les4 ,:5 x is consid]$ t mank9d works "u artificial light ) an int5sity ( only a few foot-c&les1 ! m>vels ( ! visual app>atus are app>5t4 ,b x %\ld be not$ t ! eyes ( ! human race evolv$ "u natural light4 ,!y h be5 us$ to great int5sities :5 call$ ^u = _! greate/ ef=ts4 ,! human be+ is wond]fully adaptive1 b x c\ld sc>cely be hop$ t ! eyes c\ld readju/ !mselves 9 a few g5]ations to ! *ang$ conditions ( l[-int5sity artificial light+4 ,!re is no compla9t aga9/ ! range ( int5sities to :i* ! eye responds1 = 9 range ( s5sibility x is sup]ior to any man-made device4 ,= extremely l[ brightnesses ano!r set ( physiological processes come into play4 ,bas$ purely ^u ! physiological laws ( vision x seems reasonable to conclude t mank9d %\ld n "w "u artificial illum9ation z l[ z has be5 consid]$ necess>y ow+ to ! co/ 9 ! pa/4 ,) ?is pr9ciple ( vision z a f\ndation1 exp]im5ts h be5 made ) great] int5sities ( illum9ation 9 ! indu/ries & else:]e & increas$ production has be5 ! result4 ,9 a te/ 9 a factory :]e an adequate record ( production 0 9 effect x 0 f\nd t an increase 9 ! int5sity ( illum9ation f #d to #ab foot-c&les increas$ ! production 9 v>i\s op]ations4 ,! l[e/ increase 9 production 0 #h p] c5t41 ! highe/ 0 #bg p] c5t41 & ! av]age 0 #ae p] c5t4 ,! orig9al light+ 9 ?is case 0 bett] ?an t ( ! typical indu/rial conditions1 s t x seems reasonable to expect a great] increase 9 production :5 a *ange is made f ! av]age inadequate light+ ( a factory to a well-design$ light+-sy/em giv+ a high int5sity ( illum9ation4 ,9 ano!r te/ ! production "u a poor sy/em ( light+ by means ( b>e lamps on drop-cords 0 comp>$ ) t ( an excell5t sy/em 9 :i* well-design$ reflectors 7 us$4 ,! int5sity ( illum9ation 9 ! latt] case 0 tw5ty-five times t ( ! =m] & ! production 0 increas$ 9 v>i\s op]ations f #cj p] c5t4 = ! lea/ increase to #ajj p] c5t4 = ! greate/ increase4 ,inasmu* z ! en]gy consumption 9 ! latt] case 0 increas$ sev5 times & ! illum9ation tw5ty-five times1 x is se5 t ! increase 9 int5sity ( illum9ation 0 due l>gely to ! use ( prop] reflectors & to ! g5]al lay\t ( ! new light+-sy/em4 ,9 ano!r case a #aj p] c5t4 increase 9 production 0 obta9$ by increas+ ! int5sity ( illum9ation f #c foot-c&les to ab\t #ab foot-c&les4 ,?is increase ( f\r times 9 ! int5sity ( illum9ation involv$ an increase 9 consumption ( electrical en]gy ( ?ree times ! orig9al am\nt at an increase 9 co/ equal to #a4b p] c5t4 ( ! pay-roll4 ,9 ano!r te/ an increase ( #aj p] c5t4 9 production 0 obta9$ at an increase 9 co/ equal to less ?an #a p] c5t4 ( ! payroll4 ,! effici5cy ( well-design$ light+ in/allations is illu/rat$ 9 ?is case1 = ! illum9ation int5sity 0 increas$ six times by d\bl+ ! consumption ( electrical en]gy4 ,v>i\s o!r te/s c\ld be cit$1 b ^! w\ld m]ely emphasize ! same results4 ,h[ev]1 x may be /at$ t ! factory sup]9t5d5ts involv$ are conv9c$ t adequate & prop] artificial light+ is a great factor 9 increas+ production4 ,mr4 ,w4 ,a4 ,durg91 :o conduct$ ! te/s1 has /at$ t ! av]age result ( increas+ ! int5sity ( illum9ation & ( prop]ly design+ ! light+ in/allations 9 factories w be at lea/ a #ae p] c5t4 increase 9 production at an increas$ co/ ( n m ?an #e p] c5t4 ( ! pay-roll4 ,?is is app>5tly a cons]vative /atem5t4 ,:5 x is consid]$ t g5]ally ! co/ ( light+ is only a fraction ( #a p] c5t4 ( ! co/ ( products to ! consum]1 x is se5 t ! additional co/ ( obta9+ an increase ( #ae p] c5t4 9 production is inappreciable4 ,indu/rial sup]9t5d5ts are j beg9n+ to see ! advantage ( adequate artificial light+1 b ! l[ /&>ds ( light+ :i* 7 inaugurat$ :5 artificial light 0 mu* m co/ly ?an x is to-day p]si/ t5aci\sly4 ,:5 high int5sities ( prop] illum9ation are once tri$1 !y inv>iably prove successful 9 ! indu/ries4 ,n only does ! work] see all 8 op]ations bett]1 b !re appe>s to be an enliv5+ effect ^u individuals "u ! high] int5sities ( illum9ation4 ,mank9d *ooses a dimly light$ room 9 :i* to re/ & to dream4 ,a room int5sely light$ by means ( well-design$ units :i* are n gl>+ is com=table b n conducive to quiet contemplation4 ,x is a place 9 :i* to be active4 ,?is is p]haps "o ( ! factors :i* makes = increas$ production "u adequate light+4 ,civilization has j pass$ ! ?re%old ( ! age ( adequate artificial light+ & only a small p]c5tage ( ! indu/ries h increas$ _! light+ /&>ds comm5surately to ! possibilities ( ! pres5t "t4 ,if high-int5sity artificial light+ 0 in/all$ 9 all ! indu/ries & a #ae p] c5t4 increase 9 production result$1 z te/s appe> to indicate1 ! increas$ production w\ld be equal to t ( ne>ly two million work]s4 ,?is great increase 9 output is br\ght ab\t by light+ at an insignificant increase 9 co/ b )\t ! additional consumption ( food or clo?+4 ,besides ?is increase 9 production !re is ! decrease 9 spoilage4 ,! sav+ possible 9 ?is respect ?r\gh adequate light+ has be5 e/imat$ = ! indu/ries ( ?is c\ntry at #ajj1jjj1jjj4 ,if mank9d is to h conv5i5ces & luxuries1 effici5cy 9 production mu/ be practis$ to ! utmo/ & 9 ! =ego+ a prov$ means has be5 discuss$4 ,!re are _m o!r ways 9 :i* artificial light may s]ve 9 increas+ production4 ,man has f\nd t eight h\rs ( sleep is suffici5t to keep him fit = "w if he has a suffici5t am\nt ( recreation4 ,be=e ! adv5t ( artificial light ! activities ( ! primitive savage 7 halt$ by d>kness4 ,?is may h be5 ,nature's int5tion1 b civiliz$ man has adapt$ himself to ! *ang$ conditions br\ght ab\t by effici5t & adequate artificial light4 ,!re appe>s to be no fundam5tal reason = n impos+ an artificial day ^u plants1 animals1 *emical processes1 etc42 &1 9 fact1 exp]im5ts are be+ prosecut$ 9 ^! directions4 ,! h51 :5 p]mitt$ to foll[ h] natural c\rse1 rises ) ! sun & goes to roo/ at sunset4 ,dur+ ! w9t] mon?s %e puts 9 %ort days (f ! roo/4 ,x has be5 %[n t an artificial day1 made by piec+ out daylight by means ( artificial light1 might keep ! h5 scrat*+ & fe$+ long]1 ) an increas$ production ( eggs z a result4 ,_m exp]im5ts ( ?is "* h be5 c>ri$ out1 & !re appe>s to be a g5]al conclusion t ! use ( artificial light = ?is purpose is pr(itable4 ,exp]im5ts conduct$ rec5tly by ! agricultural dep>tm5t ( a l>ge univ]sity indicate t 9 p\ltry husb&ry1 :5 artificial light is appli$ to ! "r k9d ( /ock ) correct me?ods ( fe$+1 ! di/ribution ( egg-production ?r\gh\t ! :ole ye> c be radically *ang$4 ,! supply ( eggs may be increas$ 9 autumn & w9t] & decreas$ 9 spr+ & summ]4 ,data on ! am\nt ( illum9ation h n be5 publi%$1 b x is said t ! mo/ satisfactory results h be5 obta9$ :5 ! artificial illum9ation is us$ f sunset until ab\t #i ,p4 ,m4 ?r\gh\t ! ye>4 ,an increase ( #cj to #dj p] c5t4 9 ! numb] ( eggs laid on a p\ltry-f>m 9 ,engl& z ! result ( in/all+ electric lamps 9 ! h5-h\ses 0 report$ 9 #aiac4 ,on ?is f>m !re 7 ne>ly #bjj y>ds ( h5-h\ses conta9+ ab\t #fjjj h5s1 & ! runs 7 light$ on d>k morn+s & e>ly nights ( ! ye> prec$+ ! report4 ,ab\t #cjj small lamps v>y+ f #h to #cb c&le-p[] 7 us$ 9 ! h\ses4 ,x 0 f\nd t an imitation ( sunset 0 necess>y by swit*+ (f ! #cb c&le-p[] lamps at #f ,p4 ,m4 & ! #af c&le-p[] lamps at #i3cj4 ,?is left only ! #h c&le-p[] lamps burn+1 & 9 ! fa9t illum9ation ! h5s s\ght ! roo/+-places4 ,at #aj ,p4 ,m4 ! rema9+ lights 7 ext+ui%$4 ,x 0 f\nd t if all ! lights 7 ext+ui%$ sudd5ly ! f[ls w5t to sleep on ! gr\nd & ?us became a prey to p>asites4 ,! increase 9 production ( eggs is br\ght ab\t m]ely by keep+ ! f[ls awake long]4 ,on ! same f>m ! gr[? ( *icks incubat$ dur+ ! w9t] mon?s increas$ by "o ?ird ?r\gh ! use ( electric light :i* kept !m fe$+ long]4 ,_m fi%]m5 w te/ify t artificial light seems to attract fi%1 & v>i\s reports h be5 circulat$ reg>d+ ! efficacy ( us+ artificial light = ?is purpose on a comm]cial scale4 ,"o report :i* be>s ! e>m>ks ( au!nticity is f ,italy1 :]e x is said t electric lights 7 successfully us$ z bait to augm5t ! supply ( fi% dur+ ! w>4 ,! lamps 7 subm]g$ to a consid]able dep? & ! fi% 7 attract$ 9 su* l>ge numb]s t ! use ( artificial light 0 pr(itable4 ,! claims made 7 t ! supply ( fi% 0 n only increas$ by night fi%+ b t a numb] ( fi%]m5 7 !reby releas$ = national s]vice dur+ ! w>4 ,an int]e/+ incid5t p]ta9+ to fi%1 b p]haps n an important factor 9 production1 is ! use ( electric lights 9 ! summ] ov] ! res]voirs ( a fi% hat*]y4 ,^! lights1 :i* hang l[1 attract myriads ( bugs1 _m ( :i* fall 9 ! wat] & furni% natural & inexp5sive food = ! fi%4 ,_m exp]im5ts h be5 c>ri$ out 9 ! =c+ ( plants by means ( artificial light4 ,"s ( ^! 7 conduct$ =ty ye>s ago1 :5 artificial light 0 m co/ly ?an at ! pres5t "t4 ,( c\rse1 x is well kn[n t light is ess5tial to plant life & 9 g5]al x is reasonable to believe t daylight is ! mo/ desirable quality ( light = plants4 ,9 gre5h\ses ! =c+ ( plants is desirable1 ow+ to ! re/rict$ area = cultivation4 ,x has be5 e/abli%$ t "s ( ! ultra-violet rays :i* are absorb$ or n transmitt$ by glass are h>mful to gr[+ plants4 ,= ?is reason an arc-lamp design$ = =c+ purposes %\ld be equipp$ ) a glass globe4 ,f4 ,w4 ,rane report$ 9 #ahid ^u "s exp]im5ts ) electric c>bon-filam5t lamps 9 gre5h\ses 9 :i* satisfactory results 7 obta9$ by us+ ! artificial light sev]al h\rs ea* night4 ,pr(4 ,l4 ,h4 ,bailey also conduct$ exp]im5ts ) ! arc-lamp & conclud$ t !re 7 b5eficial results if ! light 0 filt]$ ?r\gh cle> glass4 ,)\t consid]+ ! details ( ! exp]im5t1 we f9d "s ( ,rane's conclusions ( int]e/1 especially :5 x is rememb]$ t ! c>bon-filam5t lamps us$ at t "t 7 ( v l[ effici5cy comp>$ ) ! filam5t lamps at ! pres5t "t4 ,"s ( 8 conclusions 7 z foll[s3 ,! inc&esc5t electric light has a m>k$ effect ^u gre5h\se plants4 ,! light appe>s to be b5eficial to "s plants gr[n = foliage1 su* z lettuce4 ,! lettuce 0 e>li]1 weigh$ m & /ood m erect4 ,fl[]+ plants blossom$ e>li] & cont9u$ to bloom long] "u ! light4 ,! light influ5ces "s plants1 su* z sp9a* & endive1 to quickly run to se$1 :i* is objectionable 9 =c+ ^! plants = sale4 ,! /rong] ! c&le-p[] ! m m>k$ ! results1 o!r conditions be+ ! same4 ,mo/ plants t5d$ t[>d a tall] gr[? "u ! light4 ,x is d\btful :e!r ! inc&esc5t light c be us$ 9 ! gre5h\se f a practical & economic /&po9t on o!r plants ?an lettuce & p]haps fl[]+ plants2 & at pres5t prices 7#ahid7 x is a "q if x w pay to employ x ev5 = ^!4 ,!re are _m po9ts ab\t ! inc&esc5t electric light t appe> to make x pref]able to ! arc light = gre5h\se use4 ,al?\gh we h n yet ?or\ghly e/abli%$ ! economy & practicability ( ! electric light ^u plant gr[?1 /ill ,i am conv9c$ t !re is a future 9 x4 ,^! are enc\rag+ conclusions1 consid]+ ! fact t ! co/ ( light f inc&esc5t lamps at ! pres5t "t is only a small fraction ( its co/ at t "t4 ,9 an exp]im5t conduct$ 9 ,engl& 9 #aiac m]cury glass-tube arcs 7 us$ 9 "o "p ( a ho?\se & ! o!r "p 0 res]v$ = a control te/4 ,! same k9d ( se$s 7 plant$ 9 ! two p>ts ( ! ho?\se & all conditions 7 ma9ta9$ ! same1 except+ t a m]cury-vapor lamp 0 op]at$ a few h\rs 9 ! ev5+ 9 "o ( !m4 ,miss ,dudgeon1 :o conduct$ ! te/1 0 en?usia/ic ov] ! results obta9$4 ,ord9>y vegetable se$s & gra9s g]m9at$ 9 eight to ?irte5 days 9 ! ho?\se 9 :i* ! artificial light 0 us$ to l5g!n ! day4 ,9 ! o!r1 g]m9ation took place 9 f twelve to fifty-sev5 days4 ,9 all cases at lea/ sev]al days 7 sav$ 9 g]m9ation & 9 "s cases sev]al weeks4 ,fl[]s also increas$ 9 foliage1 & a #be p] c5t4 increase 9 ! crop ( /rawb]ries 0 not$4 ,se$l+s produc$ "u ! =c+ by artificial light ne$$ virtually no h>d5+ be=e be+ plant$ 9 ! op54 ,pr(essor ,prie/ley ( ,bri/ol ,univ]sity said ( ?is "w3 ,! light seems to h be5 extraord9>ily efficaci\s1 produc+ accel]at$ g]m9ation1 increas$ gr[?1 great] dep? ( color1 & m important /ill1 no signs ( lanky1 unnatural ext5sion ( plant usually associat$ ) =c+4 ,r ! plants expos$ to ! radiation seem to h gr[n if any?+ m /urdy ?an ! control plants4 ,a /ructural exam9ation ( ! exp]im5tal & control plants c>ri$ out by means ( ! microscope fully confirm$ ,miss ,dudgeon's /atem5ts bo? z to dep? ( color & great] /urd9ess ( ! treat$ plants4 ,un=tunately !re is mu* confusion amid ! results ( exp]im5ts p]ta9+ to ! effects ( diff]5t rays1 includ+ ultra-violet1 visible & infra-r$1 ^u plant gr[?4 ,if ?is aspect 0 ?or\ghly e/abli%$1 inve/igations c\ld be outl9$ to great] advantage & effici5t light-s\rces c\ld be *os5 ) c]ta9ty4 ,!re is ! disc\rag+ feature t ! av]age int5sity ( daylight illum9ation f sunrise to sunset 9 ! summ]-"t is sev]al ?\s& foot-c&les4 ,! co/ ( obta9+ ?is great int5sity by means ( artificial light w\ld be prohibitive4 ,h[ev]1 ! daylight illum9ation 9 a gre5h\se 9 w9t] is v mu* less ?an ! int5sity outdoors 9 summ]4 ,inde$1 ?is int5sity p]haps av]ages only a few hundr$ foot-c&les 9 w9t]4 ,!re is enc\ragem5t 9 ?is fact & !re is hope t a little light is relatively mu* m effective ?an a great am\nt4 ,express$ 9 ano!r mann]1 x is possible t a little light is mu* m effective ?an no light at all4 ,exp]im5ts ) artificial light indicate v g5]ally an increas$ gr[?4 ,rec5tly ,hayd5 & ,/e9metz exp]im5t$ ) a plot ( gr\nd #e feet by #i feet1 ov] :i* 7 hung five #ejj-watt gas-fill$ tung/5 lamps #c feet above ! gr\nd & #ag in*es ap>t4 ,! lamps 7 equipp$ ) reflectors & ! result+ illum9ation 0 #gjj foot-c&les4 ,?is is an extremely high int5sity ( artificial illum9ation & is comp>able ) daylight 9 gre5h\ses4 ,! only se$s plant$ 7 ^? ( /r+ beans & two b$s 7 c>ri$ ?r\gh to maturity1 "o light$ by daylight only & ! o!r by daylight & artificial light1 ! latt] be+ 9 op]ation tw5ty-f\rs h\rs p] day4 ,! plants "u ! additional artificial light grew m rapidly ?an ! o!rs1 & ( ! v>i\s records kept ! ga9 9 "t 0 9 all cases ab\t #ej p] c5t4 ,f ! /&po9t ( pr(itabl5ess ! artificial light+ 0 n ju/ifi$4 ,h[ev]1 !re are sev]al po9ts to be br\ght out be=e consid]+ ?is conclusion too s]i\sly4 ,fir/1 x appe>s unwise to use ! artificial light dur+ ! day2 second1 x appe>s possible t a few h\rs ( artificial light 9 ! ev5+ w\ld suffice = consid]able =c+2 ?ird1 x is possible t a mu* l[] int5sity ( artificial light might be m effective p] lum5 ?an ! great int5sity us$2 f\r?1 x is q possible t "s o!r effici5t light-s\rce may be m effective 9 =c+ ! gr[? ( plants4 ,^! & _m o!r factors mu/ be c>efully det]m9$ be=e judgm5t c be pass$ on ! efficacy ( artificial light 9 r$uc+ ! co/ ( liv+ 9 ?is direction4 ,c]ta9ly1 artificial light has be5 %[n to increase ! gr[? ( plants & x appe>s probable t future g5]ations at lea/ w f9d x pr(itable to use ! effici5t light-produc]s ( ! com+ ages 9 ?is mann]4 ,_m o!r in/ances c\ld be cit$ 9 :i* artificial light is v closely associat$ ) ! co/ ( liv+4 ,ov]seas %ipm5t ( fruit f ! ,canadian ,nor?we/ is responsible = a decid$ innovation 9 fruit-pick+4 ,9 se>*+ = a cause ( rott+ dur+ %ipm5t x 0 f9ally conclud$ t ! temp]ature at ! "t ( pick+ 0 ! controll+ factor4 ,z a consequ5ce1 daytime 0 consid]$ undesirable = pick+ & an electric company suppli$ electric light+ = ! or*>ds 9 ord] t ! pick+ might be done dur+ ! cool ( night4 ,?is *ange is said to h rem$i$ ! situation4 ,cases ( ?re%+ & o!r agricultural op]ations be+ c>ri$ on at night are becom+ m num]\s4 ,^! are j ! beg9n+s ( artificial light 9 a new field or 9 a new relation to civilization4 ,its economic value has be5 demon/rat$ 9 ! ord9>y fields ( light+ & ^! new applications are m]ely ! initial skirmi%es :i* prec$e ! conque/ ( new t]ritory4 ,! mod]n illum9ants h be5 develop$ s rec5tly t ! new possibilities h n yet be5 e/abli%$4 ,h[ev]1 artificial light is already a factor on ! side ( ! p 9 ! /ruggle aga9/ ! increas+ co/ ( liv+1 & its future 9 ?is direction is /ill m promis+4 ,,xix ,,artificial ,,light ,,& ,,*emi/ry ,"s "o 9 an e>ly c5tury 0 ! fir/ to notice t ! sun's rays tann$ ! sk91 & ?is unkn[n individual made ! initial discov]y 9 :at is n[ an ext5sive bran* ( sci5ce kn[n z photo-*emi/ry4 ,! fad+ ( dyes1 ! blea*+ ( textiles1 ! d>k5+ ( silv] salts1 ! syn!sis & decomposition ( comp\nds are common examples ( *emical reactions induc$ by light4 ,!re are ?\s&s ( o!r examples ( ! *emical effects ( light "s ( :i* h be5 utiliz$ by mank9d4 ,o!rs await ! developm5t ( m effici5t light-s\rces emitt+ great] quantities ( active rays1 & _m /ill rema9 int]e/+ sci5tific facts )\t any app>5t practical applications at ! pres5t "t4 ,visible & ultra-violet rays are ! radiations almo/ entirely responsible = photo*emical reactions1 b ! mo/ active ( ^! are ! blue1 violet1 & ultra-violet rays4 ,^! are (t5 designat$ *emical or act9ic rays 9 ord] to di/+ui% ! gr\p z a :ole f o!r gr\ps su* z ultra-violet1 visible1 & infra-r$4 ,light is a unique ag5t 9 *emical reactions because x is n a mat]ial sub/ance4 ,x nei!r contam9ates nor leaves a residue4 ,al?\gh mu* in=mation p]ta9+ to photo*emi/ry has be5 available = ye>s1 ! abs5ce ( p[]ful light-s\rces emitt+ s-call$ *emical rays 9 l>ge quantities inhibit$ ! practical developm5t ( ! sci5ce ( photo*emi/ry4 ,ev5 to-day1 ) va/ applications ( light 9 ?is mann]1 mank9d is only beg9n+ to utilize its *emical p[]s4 ,illu/ration3 ,9 a mov+-picture /udio ,9 a portrait /udio ,,artificial ,,light ,,9 ,,photography ,illu/ration3 ,swimm+ pool ,city wat]works ,,/]iliz+ ,,wat] ,,) ,,radiant ,,en]gy ,,f ,,qu>tz ,,m]cury-,,arcs ,al?\gh x appe>s t ! *emical action ( light 0 kn[n to ! anci5ts1 ! e>lie/ photo*emical inve/igations :i* c\ld be consid]$ sci5tific & sy/ematic 7 ^? ( ,k4 ,w4 ,s*eele 9 #aggg on silv] salts4 ,an extract f 8 own acc\nt is z foll[s3 ,i precipitat$ a solution ( silv] by sal-ammoniac2 !n ,i edulcorat$ 7wa%$7 x & dri$ ! precipitate & expos$ x to ! beams ( ! sun = two weeks2 aft] :i* ,i /irr$ ! p[d] & repeat$ ! same sev]al times4 ,h]eupon ,i p\r$ "s cau/ic _s ( sal-ammoniac 7/rong ammonia7 on ?is1 9 all appe>ance1 black p[d]1 & set x by = dige/ion4 ,?is m5/ruum 7solv5t7 dissolv$ a quantity ( luna cornua 7horn silv]71 ?\gh "s black p[d] rema9$ undissolv$4 ,! p[d] hav+ be5 wa%$ 01 = ! great] "p1 dissolv$ by a pure acid ( nitre 7nitric acid71 :i*1 by ! op]ation1 acquir$ volatility4 ,?is solution ,i precipitat$ aga9 by means ( sal-ammoniac into horn silv]4 ,h5ce x foll[s t ! blackness :i* ! luna cornua acquires f ! sun's light1 & likewise ! solution ( silv] p\r$ on *alk1 is silv] by r$uction4 ,i mix$ s mu* ( di/ill$ wat] ) ! well-wa%$ horn silv] z w\ld j cov] ?is p[d]4 ,! half ( ?is mixture ,i p\r$ into a :ite cry/al phial1 expos$ x to ! beams ( ! sun1 & %ook x sev]al times ea* day2 ! o!r half ,i set 9 a d>k place4 ,aft] hav+ expos$ ! "o mixture dur+ ! space ( two weeks1 ,i filtrat$ ! wat] /&+ ov] ! horn silv]1 gr[n already black2 ,i let "s ( ?is wat] fall by drops 9 a solution ( silv]1 :i* 0 imm$iately precipitat$ into horn silv]4 ,?is extract %[s t ,s*eele dealt ) ! r$uc+ action ( light4 ,he f\nd t silv] *loride 0 decompos$ by light & t !re 0 a lib]ation ( *lor9e4 ,h[ev]1 x 0 le>n$ lat] t dri$ silv] *loride seal$ 9 a tube f :i* ! air 0 exhau/$ is n discolor$ by light & t sub/ances mu/ be pres5t to absorb ! *lor9e4 ,s*eele's "w ar\s$ mu* int]e/ 9 photo*emical effects & _m inve/igations foll[$4 ,9 _m ( ^! ! sup]iority ( blue1 violet1 & ultra-violet rays 0 demon/rat$4 ,9 #ahjb ! fir/ photograph 0 made by ,w$gwood1 :o copi$ pa9t+s ^u glass & made pr(iles by ca/+ %ad[s ^u a s5sitive *emical comp\nd4 ,h[ev]1 he 0 n able to fix ! image4 ,mu* /udy & exp]im5tation 7 exp5d$ ^u photo*emical effects1 especially ) silv] comp\nds1 be=e ,niepce develop$ a me?od ( produc+ pictures :i* 7 subsequ5tly unaffect$ by light4 ,lat] ,dagu]re became associat$ ) ,niepce & ! fam\s dagu]reotype 0 ! result4 ,app>5tly ! latt] 0 *iefly responsible = ! developm5t ( ?is fir/ comm]cial process1 ! products ( :i* are /ill to be f\nd 9 ! family album4 ,a c5tury has elaps$ s9ce ?is e>lie/ p]iod ( comm]cial photography1 & dur+ ea* ye> progress has be5 made1 until at ! pres5t "t photography is ?or\ghly wov5 into ! activities ( civiliz$ mank9d4 ,9 ^? e>lie/ ye>s a p]son 0 oblig$ to sit motionless 9 ! sun = m9utes 9 ord] to h 8 picture tak54 ,! developm5t ( a c5tury is exemplifi$ 9 ! snap%ot ( ! pres5t "t4 ,photographic exposures outdoors at pres5t are commonly "o ?\s&? ( a second1 & indoors "u mod]n artificial light miles ( mov+-picture film are made daily 9 :i* ! individual exposures are v small fractions ( a second4 ,artificial light is play+ a great "p 9 ?is bran* ( photo*emi/ry1 & ! developm5t ( artificial light = ! v>i\s photographic ne$s is be/ emphasiz$ by rem9d+ ! read] t ! s\rces mu/ be g5]ally comp>able ) ! sun 9 act9ic or *emical p[]4 ,! int5sity ( illum9ation due to sunlight on a cle> day :5 ! sun is ne> ! z5i? is commonly #aj1jjj foot-c&les on a surface p]p5dicul> to ! direct rays4 ,?is is equival5t to ! illum9ation due to a s\rce #ij1jjj c&le-p[] at a di/ance ( ?ree feet4 ,! sun deliv]s ab\t #bjj1jjj1jjj1jjj horse-p[] to ! e>? cont9u\sly1 :i* is e/imat$ to be ab\t "o million times ! am\nt ( p[] g5]at$ artificially on ! e>?4 ,( ?is inconceivable quantity ( en]gy a small "p is absorb$ by vegetation1 "s is reflect$ & radiat$ back into space1 & ! balance heats ! e>?4 ,to /ore "s ( ?is en]gy s t x may be utiliz$ at w 9 any desir$ =m is "o ( ! dreams ( sci5ce4 ,h[ev]1 artificial light-s\rces are dep5d$ ^u at pres5t 9 _m photographic & o!r *emical processes4 ,al?\gh two illum9ants may be ( ! same lum9\s int5sity1 !y may diff] widely 9 act9ic value4 ,x is impossible to rate ! diff]5t illum9ants 9 a g5]al mann] z to act9ic value because ! v>i\s photo*emical reactions are n affect$ to ! same ext5t by rays ( a giv5 wave-l5g?4 ,ne>ly all human eyes see visible rays 9 approximately ! same mann]1 b ! multitude ( *emical reactions %[ a wide v>iation 9 s5sitivity to ! v>i\s rays4 ,= example1 "o photographic emulsion may be s5sitive only to ultra-violet1 violet1 & blue rays & ano!r to all ^! rays & also to ! gre51 yell[1 & r$4 ,!re=e1 "o illum9ant may be sup]ior to ano!r = "o photo*emical reaction1 :ile ! rev]se may be true 9 ! case ( ano!r reaction4 ,9 g5]al1 x may be said t ! arc-lamps includ+ ! m]cury-arcs provide ! mo/ active illum9ants = photo*emical processes2 h[ev]1 a l>ge numb] ( electric inc&esc5t filam5t lamps are us$ 9 photographic "w4 ,! photo-engrav] has be5 indep5d5t ( sunlight s9ce ! practical developm5t ( 8 art4 ,9 fact1 ! pr9t] c\ld n dep5d ^u sunlight = mak+ ! engrav+s :i* are us$ to illu/rate ! magaz9es & newspap]s4 ,! newspap] photograph] may make a fla%light exposure1 develop 8 negative1 & make a pr9t f x "u artificial light4 ,he may turn ?is ov] to ! photo-engrav] :o c>ries out 8 "w by means ( p[]ful arc-lamps & 9 an h\r or two aft] ! orig9al exposure 0 made ! newspap] conta9+ ! illu/ration is be+ sold on ! /reets4 ,! mov+-picture /udio is indep5d5t ( daylight 9 indoor sett+s & !re is a t5d5cy t[>d ! exclusive use ( artificial light4 ,9 ?is field m]cury-vapor lamps1 arc-lamps1 & tung/5 photographic lamps are us$4 ,simil>ly1 9 ! portrait /udio !re is a t5d5cy = ! photograph] to leave ! skylight$ upp] floors & to utilize artificial light4 ,9 ?is field ! tung/5 photographic lamp is ga9+ 9 popul>ity1 ow+ to its simplicity & to o!r advantages4 ,artificial light 9 g5]al is m satisfactory ?an natural light = _m k9ds ( photographic "w because ?r\gh ! ease ( controll+ x a great] v>iety ( m arti/ic effects may be obta9$4 ,9 ord9>y photographic pr9t+ tung/5 lamps are widely us$1 b 9 blue-pr9t+ ! :ite flame-arc & ! m]cury-vapor lamp are g5]ally employ$4 ,n _m ye>s ago ! blue-pr9t] wait$ = ! sun to appe> 9 ord] to make 8 pr9ts1 b to-day l>ge ma*9es op]ate cont9u\sly "u ! light ( p[]ful artificial s\rces4 ,h[ _m realize t ! blue-pr9t is almo/ univ]sally at ! f\ndation ( ev]y?+ at ! pres5t "t8 ,n only are products made f blue-pr9ts b ! ma*9]y :i* makes ! products is built f blue-pr9ts4 ,ev5 ! build+ :i* h\ses ! ma*9]y is fir/ con/ruct$ f blue-pr9ts4 ,!y =m an endless *a9 9 ! activities ( pres5t civilization4 ,artificial light has be5 a great factor 9 ! practical developm5t ( photography & x is look$ ^u = aid 9 _m o!r directions4 ,al?\gh !re is a multitude ( reactions 9 photographic processes :i* are br\ght ab\t by exposure to light1 ^! repres5t relatively few ( ! photo*emical reactions4 ,9 g5]al1 x may be /at$ t light is capable ( caus+ ne>ly e type ( reaction4 ,! *emical comp\nds :i* are photo-s5sitive are v num]\s4 ,_m ( ! comp\nds ( silv]1 gold1 plat9um1 m]cury1 iron1 copp]1 manganese1 lead1 nickel1 & t9 are photo-s5sitive & ^! h be5 widely inve/igat$4 ,light & oxyg5 cause _m oxidation reactions &1 on ! o!r h&1 light r$uces _m comp\nds su* z silv] salts1 ev5 to ! ext5t ( lib]at+ ! metal4 ,oxyg5 is conv]t$ p>tially into ozone "u ! influ5ce ( c]ta9 rays & !re are _m examples ( polym]ization caus$ by light4 ,v>i\s allotropic *anges ( ! elem5ts are due to ! influ5ce ( light2 = example1 a sulphur soluble 9 c>bon disulphide is conv]t$ into sulphur :i* is insoluble1 & ! rate ( *ange ( yell[ phosphorus into ! r$ v>iety is greatly accel]at$ by light4 ,hydrog5 & *lor9e comb9e "u ! action ( light ) explosive rapidity to =m hydro*loric acid & !re are _m o!r examples ( ! syn!siz+ action ( light4 ,c>bon monoxide & *lor9e comb9e to =m phosg5e & ! comb9ation ( *lor9e1 brom9e1 & iod9e1 ) organic comp\nds1 is mu* ha/5$ by expos+ ! mixture to light4 ,9 a simil> mann] _m decompositions are due to light2 = example1 hydrog5 p]oxide is decompos$ into wat] & oxyg54 ,?is sugge/s ! reason = ! use ( br[n bottles z conta9]s = _m *emical comp\nds4 ,su* glass does n transmit appreciably ! s-call$ act9ic or *emical rays4 ,!re is a l>ge numb] ( reactions due to light 9 organic *emi/ry & "o ( fundam5tal importance to mank9d is ! effect ( light on ! *lorophyll1 ! gre5 color+ matt] 9 vegetation4 ,no p]man5t *ange takes place 9 ! *lorophyll1 b by ! action ( light x enables ! plant to absorb oxyg51 c>bon dioxide1 & wat] & to use ^! to build up ! complex organic sub/ances :i* are f\nd 9 plants4 ,radiant en]gy or light is absorb$ & conv]t$ into *emical en]gy4 ,?is use ( radiant en]gy occurs only 9 ^? p>ts ( ! plant 9 :i* *lorophyll is pres5t1 t is1 9 ! leaves & /ems4 ,^! p>ts absorb ! radiant en]gy & take c>bon dioxide f ! air ?r\gh brea?+ op5+s4 ,!y conv]t ! radiant en]gy into *emical en]gy & use ?is en]gy 9 decompos+ ! c>bon dioxide4 ,! oxyg5 is exhau/$ & ! c>bon ent]s into ! /ructure ( ! plant4 ,! en]gy ( plant life ?us comes f radiant en]gy & ) ?is aid ! simple comp\nds1 su* z ! c>bon dioxide ( ! air & ! phosphates & nitrates ( ! soil1 are built into complex /ructures4 ,?us plants are con/ructive & syn!tic 9 op]ation4 ,x is int]e/+ to note t ! animal organism conv]ts complex comp\nds into me*anical & heat en]gy4 ,! animal organism dep5ds ^u ! syn!tic "w ( plants1 consum+ z food ! complex /ructures built by !m "u ! action ( light4 ,= example1 plants inhale c>bon dioxide1 lib]ate ! oxyg51 & /ore ! c>bon 9 complex comp\nds1 :ile ! animal uses oxyg5 to burn up ! complex comp\nds d]iv$ f plants & exhales c>bon dioxide4 ,x is a beautiful cycle1 :i* %[s t ultimately all life on e>? dep5ds ^u light & o!r radiant en]gy associat$ ) x4 ,contr>y to mo/ photo*emical reactions1 x appe>s t plant life utilize yell[1 r$1 & infra-r$ en]gy m ?an ! blue1 violet1 & ultra-violet4 ,9 g5]al1 great int5sities ( blue light & ( ! closely associat$ rays are necess>y = mo/ photo*emical reactions ) :i* man is indu/rially int]e/$4 ,x has be5 f\nd t ! :ite flame-arc excels o!r artificial light-s\rces 9 ha/5+ ! *lor9ation ( natural gas 9 ! production ( *lor(orm4 ,"o advantage ( ! radiation f ?is light-s\rce is t x does n ext5d f> into ! ultra-violet1 = ! ultra-violet rays ( %ort wave-l5g?s decompose "s comp\nds4 ,9 o!r words1 x is necess>y to *oose radiation :i* is effective b :i* does n h rays associat$ ) x t de/roy ! desir$ products ( ! reaction4 ,by ! use ( a %unt across ! arc ! light c be gradually v>i$ ov] a consid]able range ( int5sity4 ,ano!r advantage ( ! flame-arc 9 photo*emi/ry is ! ease ) :i* ! quality or spectral "* ( ! radiant en]gy may be alt]$ by v>y+ ! *emical salts us$ 9 ! c>bons4 ,= example1 /rontium fluoride is us$ 9 ! r$ flame-arc ^: radiant en]gy is ri* 9 r$ & yell[4 ,calcium fluoride is us$ 9 ! c>bons ( ! yell[ flame-arc :i* emits excessive r$ & gre5 rays caus+ by visual syn!sis ! yell[ color4 ,! radiant en]gy emitt$ by ! sn[-:ite flame-arc is a close approximation to av]age daylight bo? z to visible & to ultra-violet rays4 ,its c>bons conta9 r>e-e>?s4 ,! uses ( ! flame-arcs are cont9ually be+ ext5d$ because !y are ( high int5sity & effici5cy & !y af=d a v>iety ( color or spectral quality4 ,a million :ite flame-c>bons are be+ us$ annually 9 ?is c\ntry = v>i\s photo*emical processes4 ,( ! hundr$s ( dyes & pigm5ts available _m are n p]man5t & until rec5t ye>s sunlight 0 dep5d$ ^u = te/+ ! p]man5cy ( color+ mat]ials4 ,z a consequ5ce su* te/s c\ld n be c>ri$ out v sy/ematically until a p[]ful artificial s\rce ( light resembl+ daylight 0 available4 ,x appe>s t ! :ite flame-arc is q satisfactory 9 ?is field1 = te/s indicate t ! *emical effect ( ?is arc 9 caus+ dye-fad+ is f\r or five times z great z t ( ! be/ ,june sunlight if ! mat]ials are plac$ )9 t5 in*es ( a #bh-;amp]e arc4 ,x has be5 comput$ t 9 sev]al days ( cont9u\s op]ation ( ?is arc ! same fad+ results c be obta9$ z 9 a ye>'s exposure to daylight 9 ! nor!rn "p ( ?is c\ntry4 ,inasmu* z ! fa/ness ( colors 9 daylight is usually ( int]e/1 ! artificial illum9ant us$ = color-fad+ %\ld be spectrally simil> to daylight4 ,app>5tly ! :ite flame-arc fulfils ?is requirem5t z well z be+ a p[]ful s\rce4 ,li?opone1 a :ite pigm5t consi/+ ( z9c sulphide & b>ium sulphate1 sometimes exhibits ! peculi> prop]ty ( d>k5+ on exposure to sunlight4 ,?is prop]ty is due to an impurity & app>5tly _c be pr$ict$ by *emical analysis4 ,dur+ ! cl\dy days & w9t] mon?s :5 p[]ful sunlight is unavailable1 ! manufactur] is 9 d\bt z to ! quality ( 8 product & he ne$s an artificial light-s\rce = te/+ x4 ,9 su* a case ! :ite flame-arc is s]v+ satisfactorily1 b x is n difficult to obta9 effects ) o!r light-s\rces 9 a %ort "t if an image ( ! light-s\rce is focus$ ^u ! mat]ial by means ( a l5s4 ,9 fact1 a d>k5+ ( li?opone may be obta9$ 9 a m9ute by focus+ ^u x ! image ( a qu>tz m]cury-arc by means ( a qu>tz l5s4 ,9 special cases ( ?is sort ! use ( a focus$ image is f> sup]ior to ! ord9>y illum9ation f ! light-s\rce1 b1 ( c\rse1 ?is is impracticable :5 te/+ a l>ge numb] ( samples simultane\sly4 ,incid5tally1 li?opone :i* turns gray or ne>ly black 9 ! sunlight rega9s its :it5ess dur+ ! night4 ,an amus+ incid5t is told ( a "y man :o pa9t$ 8 boat "o night ) a :ite pa9t 9 :i* li?opone 0 ! pigm5t4 ,on return+ home ! next aft]noon aft] ! boat _h be5 expos$ to sunlight all day1 he 0 a/oni%$ to see t x 0 black4 ,be+ v mu* p]turb$1 he telephon$ to ! pa9t /ore1 b ! proprietor escap$ a sca?+ lecture by hav+ clos$ 8 %op at ! usual h\r4 ,! "y man telephon$ 9 ! morn+ & told ! proprietor :at _h happ5$1 b on be+ ask$ to make c]ta9 ( ! facts he w5t to ! w9d[ & look$ at 8 boat & behold6 x 0 :ite4 ,x _h rega9$ :it5ess dur+ ! night b w\ld turn black aga9 dur+ ! day4 ,al?\gh pigm5ts & dyes are n g5]ally z peculi> z li?opone1 mu* unc]ta9ty is elim9at$ by sy/ematic te/s "u con/ant1 cont9u\s1 & controllable artificial light4 ,! s\rces ( s-call$ *emical rays are num]\s = laboratory "w1 b !re is a ne$ = highly effici5t p[]ful produc]s ( ?is k9d ( en]gy4 ,9 g5]al ! flame-arcs p]haps are =emo/ s\rces at ! pres5t "t1 ) o!r k9ds ( c>bon arcs & ! qu>tz m]cury-arc rank+ next4 ,"o advantage ( ! m]cury-arc is its con/ancy4 ,fur!rmore1 = "w ) a s+le wave-l5g? x is easy to isolate "o ( ! spectral l9es4 ,! regul> glass-tube m]cury-arc is an effici5t produc] ( ! act9ic rays & z a consequ5ce has be5 ext5sively us$ 9 photographic "w & 9 o!r photo*emical processes4 ,an excell5t s\rce = exp]im5tal "w c be made easily by produc+ an arc betwe5 two small iron rods4 ,! electric sp>k has s]v$ 9 mu* exp]im5tal "w1 b ! total radiant en]gy f x is small4 ,by v>y+ ! metals us$ = electrodes a consid]able v>iety 9 ! radiant en]gy is possible4 ,?is is also true ( ! electric arcs1 & ! flame-arcs may be v>i$ widely by us+ diff]5t *emical comp\nds 9 ! c>bons4 ,!re are o!r effects ( light :i* h f\nd applications b n 9 *emical reactions4 ,= example1 sel5ium *anges its electrical resi/ance "u ! influ5ce ( light & _m applications ( ?is ph5om5on h be5 made4 ,ano!r gr\p ( light-effects =ms a bran* ( sci5ce kn[n z photo-electricity4 ,if a sp>k-gap is illum9at$ by ultra-violet rays1 ! resi/ance ( ! gap is dim9i%$4 ,if an insulat$ z9c plate is illum9at$ by ultra-violet or violet rays1 x w gradually become positively *>g$4 ,^! effects are due to ! emission ( electrons f ! metal4 ,violet & ultra-violet rays w cause a colorless glass conta9+ manganese to assume a p9ki% color4 ,! latt] is ! color :i* manganese imp>ts to glass & "u ! influ5ce ( ^! rays ! color is augm5t$4 ,c]ta9 ultra-violet rays also ionize ! air & cause ! =mation ( ozone4 ,?is c be detect$ ne> a qu>tz m]cury-arc1 = example1 by ! *>act]i/ic odor4 ,! =ego+ are only a few ( ! multitude ( photo*emical reactions & o!r effects ( radiant en]gy4 ,! developm5t ( ?is field awaits to "s ext5t ! production ( s-call$ act9ic rays m effici5tly & 9 great] quantities1 b !re are n[ _m practical applications ( artificial light = ^! purposes4 ,9 ! ext5sive fields ( photography v>i\s artificial light-s\rces h s]v$ = _m ye>s & !y are con/antly f9d+ m applications4 ,artificial light is n[ us$ to a consid]able ext5t 9 ! indu/ries 9 connection ) *emical processes1 b little in=mation is available1 ow+ to ! secrecy att5d+ ^! new developm5ts 9 indu/rial processes4 ,h[ev]1 ?is brief *apt] has be5 introduc$ 9 ord] to indicate ano!r field ( activity 9 :i* artificial light is s]v+4 ,x is agre$ by sci5ti/s t photo*emi/ry has a promis+ future4 ,mank9d h>nesses nature's =ces & produces light & ?is light is put to "w to ex]t its influ5ce = ! fur!r b5efit ( mank9d4 ,sci5ce has be5 at "w sy/ematically = only a c5tury1 b ! accompli%m5ts h be5 s wond]ful t ! imag9ation d>es n attempt to prophesy ! a*ievem5ts ( ! next c5tury4 ,,xx ,,light ,,& ,,heal? ,! human be+ evolv$ )\t clo?+ & ! body 0 ba!d ) light ?r\gh\t ! day1 b civilization has gone to ! o!r extreme ( cov]+ ! body ) clo?+ :i* keeps mo/ ( x 9 d>kness4 ,inasmu* z light & ! invisible radiant en]gy :i* is associat$ ) x are kn[n to be v influ5tial ag5cies 9 a multitude ( ways1 ! "q arises3 ,has ?is %ield+ ( ! body _h any m>k$ influ5ce ^u ! human organism8 ,al?\gh !re is a va/ lit]ature ^u ! subject ( light-!rapy1 ! "q rema9s unansw]$1 ow+ to ! conflict+ results & ! abs5ce ( /&>dization ( exp]im5tal details4 ,9 fact1 mo/ inve/igations are subject to ! criticism t ! data are inadequate4 ,?r\gh\t _m c5turies light has be5 cr$it$ ) v>i\s influ5ces ^u physiological processes & ^u ! m9d4 ,b mo/ ( ! e>ly applications _h no f\ndation ( sci5tific facts4 ,un=tunately1 _m ( ! claims p]ta9+ to ! physiological & psy*ological effects ( light at ! pres5t "t are conflict+ & !y d n re/ ^u an e/abli%$ sci5tific f\ndation4 ,fur!rmore "s ( !m are at v>iance ) ! possibilities & an unprejudic$ obs]v] mu/ conclude t mu* sy/ematic "w mu/ be done be=e ord] may arise f ! pres5t *aos4 ,?is does n mean t _m ( ! effects are n real1 = radiant en]gy is kn[n to cause c]ta9 effects1 & view+ ! subject broadly x appe>s t light is already s]v+ humanity 9 ?is field & t its future is promis+4 ,! pres5t lack ( def9ite data p]ta9+ to ! effects ( radiation is due to ! failure ( mo/ inve/igators to det]m9e accurately ! quantities & wave-l5g?s ( ! rays involv$4 ,= example1 x is easy to err by attribut+ an effect to visible rays :5 ! effect may be caus$ by accompany+ invisible rays4 ,fur!rmore1 x may be possible t c]ta9 rays c\nt]act or aid ! effective rays )\t be+ effective alone4 ,9 o!r words1 ! physical measurem5ts h be5 neglect$ not)/&+ ! fact t !y are g5]ally m easily made ?an ! det]m9ations ( curative effects or ( g]micidal action4 ,radiant en]gy ( all k9ds & wave-l5g?s has play$ a "p 9 !rapeutics1 s x is ( int]e/ to indicate !m accord+ to wave-l5g? or frequ5cy4 ,^! gr\ps v>y 9 range ( wave-l5g?1 b ! actual int]vals are n p>ticul>ly ( int]e/ "h4 ,beg9n+ ) radiant en]gy ( highe/ frequ5cies ( vibration & %orte/ wave-l5g?s1 ! foll[+ gr\ps & subgr\ps are giv5 9 _! ord] ( increas+ wave-l5g?3 ,rntg5 or ,x-rays1 :i* pass readily ?r\gh _m sub/ances opaque to ord9>y light-rays4 ,ultra-violet rays1 :i* are divid$ empirically into ?ree gr\ps1 designat$ z extreme1 middle1 & ne> 9 accordance ) _! location 9 respect to ! visible region4 ,visible rays produc+ v>i\s s5sations ( color1 su* z violet1 blue1 gre51 yell[1 orange1 & r$4 ,infra-r$ or ! invisible rays bord]+ on ! r$ rays4 ,an unkn[n1 unmeasur$1 or unfill$ region betwe5 ! infra-r$ & ! electric waves4 ,electric waves1 :i* include a class ( electromagnetic radiant en]gy ( long wave-l5g?4 ,( ^! ! ,h]zian waves are ( ! %orte/ wave-l5g? & ^! are foll[$ by wireless waves4 ,electric waves ( /ill great] wave-l5g? are due to ! sl[] oscillations 9 c]ta9 electric circuits caus$ by lightn+ dis*>ges1 etc4 ,! ,rntg5 rays 7 discov]$ by ,rntg5 9 #ahif & !y h be5 /udi$ & appli$ v widely ev] s9ce4 ,_! great use has be5 9 ,x-ray photography1 b !y are also be+ us$ 9 !rapeutics4 ,! extreme ultra-violet rays are n available 9 sunlight & are available only ne> a s\rce ri* 9 ultra-violet rays1 su* z ! arc-lamps4 ,!y are absorb$ by air1 s t !y are /udi$ 9 a vacuum4 ,^! are ! rays :i* conv]t oxyg5 into ozone because ! =m] /rongly absorbs !m4 ,! middle ultra-violet rays are n f\nd 9 sunlight1 because !y are absorb$ by ! atmosph]e4 ,!y are also absorb$ by ord9>y glass b are freely transmitt$ by qu>tz4 ,! ne>] ultra-violet rays are f\nd 9 sunlight & 9 mo/ artificial illum9ants & are transmitt$ by ord9>y glass4 ,next to ?is region is ! visible spectrum ) ! v>i\s colors1 f violet to r$1 induc$ by radiant en]gy ( increas+ wave-l5g?4 ,! infra-r$ rays are sometimes call$ heat-rays1 b all radiant en]gy may be conv]t$ into heat4 ,v>i\s sub/ances transmit & absorb ^! rays 9 g5]al q diff]5tly f ! visible rays4 ,wat] is opaque to mo/ ( ! infra-r$ rays4 ,next !re is a region ( wave-l5g?s or frequ5cies = :i* no radiant en]gy has be5 f\nd4 ,! s-call$ electric waves v>y 9 wave-l5g? ov] a great range & !y include ^? employ$ 9 wireless telegraphy4 ,all ^! radiations are ( ! same g5]al "*1 consi/+ ( electromagnetic en]gy1 b diff]+ 9 wave-l5g? or frequ5cy ( vibration & also 9 _! effects4 ,9 effect !y may ov]lap 9 _m cases & ! :ole is a *aos if ! physical details ( quantity & wave-l5g? are n specifi$ 9 exp]im5tal "w4 ,illu/ration3 ,9 art "w ,9 a hab]da%]y ,,judg+ ,,color ,,"u ,,artificial ,,daylight ,illu/ration3 ,9 an und]gr\nd tunnel ,9 an art gall]y ,,artificial ,,daylight ,x has be5 conclusively %[n t radiant en]gy kills bact]ia4 ,! e>ly exp]im5ts 7 made ) sunlight & ! de/ruction ( micro-organisms is g5]ally attribut$ to ! s-call$ *emical rays1 namely1 ! blue1 violet1 & ultra-violet rays4 ,x appe>s 9 g5]al t ! middle ultra-violet rays are ! mo/ p[]ful de/roy]s4 ,x is c]ta9ly e/abli%$ t sunlight /]ilizes wat]1 = example1 & ! qu>tz m]cury-lamp is 9 daily use = ?is purpose on a practicable scale4 ,h[ev]1 !re /ill appe>s to be a diff]5ce ( op9ion z to ! de/ructive effect ( radiant en]gy ^u bact]ia 9 liv+ tissue4 ,x has be5 %[n t ! middle ultra-violet rays de/roy animal tissue &1 = example1 cause eye-cat>acts4 ,x appe>s possible f "s exp]im5ts t ultra-violet rays de/roy bact]ia 9 wat] & on culture plates m effectively 9 ! abs5ce ( visible rays ?an :5 ^! att5d ! ultra-violet rays z 9 ! case ( sunlight4 ,?is is "o ( ! reasons = ! use ( blue glass 9 light-!rapy1 :i* isolates ! blue1 violet1 & ne> ultra-violet rays f ! o!r visible rays4 ,if ! infra-r$ rays are n desir$ !y c be readily elim9at$ by ! use ( a wat]-cell4 ,!re is a va/ am\nt ( te/imony :i* proves ! bact]icidal action ( light4 ,bact]ia on ! surface ( ! body are de/roy$ by ultra-violet rays4 ,typhus & tub]cle bacilli are de/roy$ equally well by ! direct rays f ! sun & f ! electric arcs4 ,cultures ( diph!ria develop 9 diffus$ daylight b are de/roy$ by direct sunlight4 ,l[] organisms 9 wat] are readily kill$ by ! radiation f any light-s\rce emitt+ ultra-violet rays comp>able ) ^? 9 direct sunlight4 ,f ! great am\nt ( data available x appe>s reasonable to conclude t radiant en]gy is a p[]ful bact]icidal ag5cy b t ! action is due *iefly to ultra-violet rays4 ,x appe>s also t no bact]ia c resi/ ^! rays if !y are int5se en\gh & are p]mitt$ to play ^u ! bact]ia long en\gh4 ,! de/ruction ( ^! organisms appe>s to be a ph5om5on ( oxidation1 = ! pres5ce ( oxyg5 appe>s to be necess>y4 ,! =ego+ rem>ks ab\t ! bact]icidal action ( radiant en]gy apply only to bact]ia 9 wat]1 9 cultures1 & on ! surface ( ! body4 ,!re is mu* unc]ta9ty z to ! ability ( radiant en]gy to de/roy bact]ia )9 liv+ tissue4 ,! active rays _c p5etrate appreciably into su* tissue & _m au?orities are conv9c$ t no direct de/ruction takes place4 ,9 fact1 x has be5 /at$ t ! s-call$ *emical rays are m de/ructive to ! tissue cells ?an to bact]ia4 ,f9s51 a pione] 9 ! use ( radiant en]gy 9 ! treatm5t ( disease1 effect$ _m wond]ful cures & believ$ t ! bact]ia 7 directly de/roy$ by ! ultra-violet rays4 ,h[ev]1 _m h s9ce come to ! conclusion t ! b5efic5t action ( ! rays is due to ! irritation :i* causes an outfl[ ( s]um1 ?us br++ m antibodies 9 contact ) ! bacilli1 & caus+ ! de/ruction ( ! latt]4 ,hot applications appe> to "w 9 ! same mann]4 ,primitive be+s ( ! tropics are kn[n to treat op5 w\nds by expos+ !m to ! direct rays ( ! sun )\t dress+s ( any k9d4 ,^! w\nds are usually infect$ & ! sun's rays r5d] !m aseptic & !y heal readily4 ,_m cases ( sores & surgical w\nds h be5 quickly heal$ by exposure to sunlight4 ,ev5 r$ light has be5 effective1 s x has be5 conclud$ by "s t rays ( almo/ any wave-l5g?1 if int5se en\gh1 w effect a cure ( ?is "* by caus+ an effusion ( s]um4 ,x has also be5 /at$ t ! *emical rays h an/hetic p[]s & h be5 us$ 9 ?is rle = _m m9or op]ations4 ,x is said t ! ,*9ese h us$ r$ light = c5turies 9 ! treatm5t ( smallpox & ?r\gh\t ! ,middle ,ages ?is practice 0 n uncommon4 ,9 ! olde/ book on m$ic9e writt5 9 ,engli% !re is an acc\nt ( a successful treatm5t ( ! son ( ,edw>d ,i = smallpox by means ( r$ light4 ,x is also /at$ t ?is treatm5t 0 adm9i/]$ ?r\gh\t ! reigns ( ,elizabe? & ( ,*>les ,,ii4 ,ano!r acc\nt /ates t a few soldi]s conf9$ 9 d>k dungeons recov]$ f smallpox )\t pitt+4 ,f9s5 also obta9$ excell5t results 9 ! treatm5t ( ?is disease by means ( r$ light4 ,h[ev]1 9 ?is case x appe>s t ! exclusion ( ! s-call$ *emical rays favors heal+ ( ! po/ules ( smallpox & t ! use ( r$ light is !re=e a negative application ( light-!rapy4 ,9 o!r words1 ! r$ light plays no "p except 9 furni%+ a light :i* does n inhibit heal+4 ,al?\gh ! s-call$ act9ic rays h curative value 9 c]ta9 cases1 !re are "s in/ances :]e light-ba?s are claim$ to be h>mful4 ,x is said t sun-ba?s to ! nak$ body are n s popul> z !y 7 =m]ly1 except = obesity1 g\t1 rheumatism1 & sluggi% metabolism1 because x is felt t ! %ort] ultra-violet rays may be h>mful4 ,^! rays are said to increase ! pulse1 respiration1 temp]ature1 & blood-pressure & may ev5 />t hemorrhages & 9 excessive am\nts cause heada*e1 palpitation1 insomnia1 & anemia4 ,^! same au?orities condemn sun-ba?s to ! nak$ body ( ! tub]cul\s1 claim+ t any cures effect$ are consummat$ despite ! injury done by ! en]gy ( %ort wave-l5g?4 ,!re is no d\bt t ^! rays are b5eficial 9 local lesions1 b x is believ$ t ! cure is due to ! irritation caus$ by ! rays & ! consequ5t bact]icidal action ( ! increas$ fl[ ( s]um1 & n to any direct b5eficial result on ! tissue-cells4 ,o!rs claim to cure tub]culosis by means ( p[]ful qu>tz m]cury-arcs equipp$ ) a glass :i* absorbs ! ultra-violet rays ( %ort] wave-l5g?s4 ,^! conclusions by a few au?orities are submitt$ = :at !y are wor? & to %[ t ?is phase ( light-!rapy is also unsettl$4 ,any "o :o has be5 9 t\* ) light-!rapy 9 a sci5tific rle is b\nd to note t mu* ignorance is display$ 9 ! use ( light 9 ?is mann]4 ,9 fact1 x appe>s safe to /ate t light-!rapy (t5 smacks ( quack]y4 ,v my/]i\s effects are sometimes attribut$ to radiant en]gy1 :i* occasionally bord] ^u sup]/ition4 ,nev]!less1 ?is k9d ( en]gy has value1 & not)/&+ ! *aos :i* /ill exi/s1 x is ( int]e/ to note "s ( ! equipm5t :i* has be5 us$4 ,"s practition]s h great confid5ce 9 ! electric ba?1 & elaborate light-ba?s h be5 devis$4 ,9 ! e>li] ye>s ( ?is k9d ( treatm5t ! electric arc 0 conspicu\s4 ,electrodes ( c>bon1 c>bon & iron1 & iron h be5 us$ :5 int5se ultra-violet rays 7 desir$4 ,! qu>tz m]cury-arc ( lat] ye>s supplies ?is ne$ admirably4 ,dr4 ,cleaves1 aft] _m ye>s ( exp]i5ce ) ! electric-arc ba?1 has /at$3 ,f ! adm9i/ration ( an electric-arc ba? !re is obta9$ an action ^u ! sk91 ! pati5t exp]i5ces a pleasant & slightly prickly s5sation4 ,!re is produc$1 ev5 f a %ort exposure1 ^u ! sk9 ( "s pati5ts a slight ery!ma1 :ile ) o!rs !re is b little su* effect ev5 f long exposures4 ,! face assumes a normal rosy color+ & an appe>ance ( refre%m5t & repose on em]g+ f ! ba? is always obs]v$4 ,f ! adm9i/ration ( ! electric-arc ba? !re is also not$ ! e/abli%m5t ( circulatory *anges ) a uni=m regulation ( ! he>t's action1 z evid5c$ by improv$ volume & sl[] pulse rate1 ! augm5tation ( ! temp]ature1 increas$ activity ( ! sk91 full] & sl[] respiration1 gradually increas$ respiratory capacity1 & dim9i%$ irritability ( ! muc\s membrane 9 tub]cul>1 bron*itic1 or a/hmatic pati5ts4 ,!re is also less5$ dis*>ge 9 ^? pati5ts suff]+ f cat>rhal conditions ( ! nasal passages4 ,9 diseases ( ! respiratory sy/em1 a soo?+ effect ^u ! muc\s membranes is always exp]i5c$1 :ile c\gh & expectoration are dim9i%$4 ,! cab9et us$ by ,dr4 ,cleaves 0 l>ge en\gh to conta9 a cot ^u :i* ! pati5t recl9$4 ,an arc-lamp 0 susp5d$ at ea* ( ! two ends ( ! cab9et & a flood ( light 0 obta9$ directly & by reflection f ! :ite inside surfaces ( ! cab9et4 ,by means ( mirrors ! light f ! arcs c\ld be conc5trat$ ^u any desir$ "p ( ! pati5t4 ,f9s51 :o 9 #ahie publi%$ 8 obs]vations ^u ! /imulat+ action ( light1 is consid]$ ! pione] 9 ! use ( s-call$ *emical rays 9 ! treatm5t ( disease4 ,he _h a circul> room ab\t ?irty-sev5 feet 9 diamet]1 9 :i* two p[]ful #ajj-;amp]e arc-lamps ab\t six feet f ! floor 7 susp5d$ f ! ceil+4 ,l[ p>titions ext5d$ radially f ! c5t]1 s t a numb] ( pati5ts c\ld be treat$ simultane\sly4 ,! temp]ature ( ! room 0 normal1 s t ! treatm5t 0 ess5tially by radiant en]gy & n by heat4 ,! *emical action ^u ! sk9 0 said to be q z /rong z "u sunlight4 ,! exposures v>i$ f t5 m9utes to an h\r4 ,light-ba?s conta9+ inc&esc5t filam5t lamps are also us$4 ,9 "s cases ! lamp1 sometimes hav+ a blue bulb1 is m]ely conta9$ z a reflector & ! light is appli$ locally z desir$4 ,light-cab9ets are also us$1 b 9 ^! !re is consid]able effect due to heat4 ,! ultra-violet rays emitt$ by ! small electric filam5t lamps us$ 9 ^! cab9ets are ( v l[ int5sity & ! bact]icidal action ( ! light mu/ be feeble4 ,! glass bulbs d n transmit ! extreme ultra-violet rays responsible = ! production ( ozone1 or ! middle ultra-violet rays :i* are effective 9 de/roy+ animal tissue4 ,! cab9ets conta9 f tw5ty to "o hundr$ inc&esc5t filam5t lamps ( ! ord9>y sizes1 f #be to #fj watts4 ,9 ! days ( ! c>bon filam5t lamp ! #af-;c&le-p[] lamp 0 us$4 ,c]ta9ly ! heat+ effect has advantages 9 "s cases ov] o!r me?ods ( heat+4 ,! light-rays p5etrate ! tissue & are absorb$ & trans=m$ into heat4 ,o!r me?ods involve conduction ( heat f ! hot air or o!r hot applications4 ,( c\rse1 x is also cont5d$ t ! light-rays are directly b5eficial4 ,light is also conc5trat$ ^u ! body by means ( l5ses & mirrors4 ,= ?is purpose ! sun1 ! arc1 ! qu>tz m]cury-arc1 & ! inc&esc5t lamp h be5 us$4 ,besides ^!1 vacuum-tube dis*>ges & sp>ks h be5 utiliz$ z s\rces = radiant en]gy & electrical treatm5t4 ,rntg5 rays & radium h also figur$ 9 rec5t ye>s 9 ! treatm5t ( disease4 ,! qu>tz m]cury-arc has be5 ext5sively us$ 9 ! pa/ decade = ! treatm5t ( sk9 diseases & !re appe>s to be less unc]ta9ty ab\t ! efficacy ( radiant en]gy = ! treatm5t ( surface diseases ?an ( o!rs4 ,h]od relat$ t ! ,egyptians treat$ pati5ts by exposure to direct sunlight & ?r\gh\t ! c5turies & among all types ( civilization sunlight has be5 recogniz$ z hav+ c]ta9 valuable heal+ or purify+ prop]ties4 ,f9s5 9 8 e>ly exp]im5ts cur$ a case ( lupus1 a tub]cul\s sk9 disease1 by means ( ! visible & ne> ultra-violet rays 9 sunlight4 ,he demon/rat$ t ^! 7 ! effective rays by us+ only ! radiant en]gy :i* pass$ ?r\gh a wat]-cell made by us+ a convex l5s = ea* end ( ! cell & fill+ ! int]v5+ space ) wat]4 ,?is 0 really a l5s made ( glass & wat]4 ,! glass absorb$ ! ultra-violet rays ( %ort] wave-l5g? & ! wat] absorb$ ! infra-r$ rays4 ,?us he 0 able to conc5trate ^u ! diseas$ sk9 radiant en]gy consi/+ ( visible & ne> ultra-violet rays4 ,! enc\rag+ results :i* ,f9s5 obta9$ 9 ! treatm5t ( sk9 diseases l$ him to become indep5d5t ( sunlight by equipp+ a special arc-lamp ) qu>tz l5ses4 ,?is gave him a p[]ful s\rce ( s-call$ *emical rays1 :i* c\ld be conc5trat$ :]ev] desir$4 ,h[ev]1 :5 sci5ce contribut$ ! m]cury-vapor arc1 developm5ts 7 imm$iately begun :i* aim$ to utilize ?is artificial s\rce ( /eady p[]ful ultra-violet rays 9 light-!rapy4 ,z a consequ5ce1 !re are n[ available v compact qu>tz m]cury-arcs design$ especially = ?is purpose4 ,app>5tly _! use has be5 v effective 9 cur+ _m sk9 diseases4 ,c]ta9ly if radiant en]gy is effective1 x has a great advantage ov] drugs4 ,an au?ority has /at$ 9 reg>d to sk9 diseases t1 treatm5t ) ! ultra-violet rays1 especially 9 conjunction ) ! ,rntg5 rays1 radium & meso?orium is t treatm5t :i* 9 mo/ in/ances holds rank z ! fir/1 & 9 _m z ! only & (t5 en\gh ! mo/ effective mode ( h&l+ ! disease4 ,/]ilization by means ( ! radiation f ! qu>tz m]cury-arc has be5 practis$ successfully = sev]al ye>s4 ,compact app>atus is 9 use = ! /]ilization ( wat] = dr9k+1 = surgical purposes1 & = swimm+-pools1 & ! claims made by ! manufactur]s ( ! app>atus app>5tly are sub/antiat$4 ,"o type ( app>atus )/&s a pressure ( "o hundr$ p\nds p] squ>e in* & may be connect$ 9 s]ies ) ! wat]-ma94 ,! wat] suppli$ to ! /]iliz] %\ld be cle> & free ( susp5d$ matt]1 9 ord] t ! radiant en]gy may be effective4 ,su* app>atus is capable ( /]iliz+ any quantity ( wat] up to a ?\s& gallons an h\r1 & ! lamp is kept burn+ only :5 ! wat] is fl[+4 ,x is especially useful 9 hotels1 /ores1 factories1 on %ips1 & 9 _m indu/ries :]e /]ile wat] is ne$$4 ,wat] is a vital necessity 9 e-day life1 :e!r = dr9k+1 cook+1 or indu/rial purposes4 ,x is recogniz$ z a c>ri] ( disease & ! purification ( wat]-supply 9 l>ge cities is an important problem4 ,*lor9ation processes are 9 use :i* r5d] ! treat$ wat] disagreeable to ! ta/e & filtration alone is look$ ^u ) suspicion4 ,! use ( *emicals requires con/ant analysis1 b x is cont5d$ t ! bact]icidal action ( ultra-violet rays is s c]ta9 & complete t !re is nev] any d\bt z to ! /]ilization ( ! wat] if x is cle>1 or if x has be5 prop]ly filt]$ be=e treat+4 ,! sy/em ( /]ilization by ultra-violet rays is ! natural way1 = ! sun's rays p]=m ?is function 9 nature4 ,app>atus = /]ilization ( wat] by means ( ultra-violet rays is built = public plants 9 capacities up to t5 million gallons p] day & ^! units may be multipli$ to meet ! ne$s ( ! l>ge/ cities4 ,l>ge me*anical filt]s are us$ 9 conjunction ) ^! /]iliz]s1 & ?us mank9d copies nature's way1 = natural supplies ( pure wat] h be5 filt]$ ?r\gh s& & h be5 expos$ to ! rays ( ! sun :i* free x f g]m life4 ,"s /]iliz]s ( ?is "* are us$ at ! place :]e a supply ( pure wat] is desir$ or at a po9t :]e wat] is bottl$ = use 9 v>i\s p>ts ( a factory1 hospital1 /ore1 or (fice build+4 ,^! 7 us$ 9 "s ,am]ican hospitals dur+ ! rec5t w>1 :]e !y suppli$ /]iliz$ wat] = dr9k+ & = ! antiseptic ba?+ ( w\nds4 ,9 w>f>e ! wat] supply is exce$+ly important4 ,= example1 ! ,japanese 9 _! campaign 9 ,man*uria boil$ ! wat] to be us$ = dr9k+ purposes4 ,! mortality ( armies 9 _m previ\s w>s 0 (t5 mu* great] f prev5table diseases ?an f bullets1 b ! ,japanese 9 _! w> ) ,russia rev]s$ ! mortality /ati/ics4 ,( a total mortality ( #ha1jjj m ?an #fj1jjj di$ ( casualties 9 battle4 ,! /]ilization ( wat] = swimm+-pools is com+ into vogue4 ,h]et(ore x 0 ! common practice to circulate ! wat] ?r\gh a filt]1 9 ord] to remove ! impurities imp>t$ to x by ! ba!rs & to return x to ! pool4 ,x is insi/$ by ! adh]5ts ( /]ilization t filtration ( ?is sort is likely to leave h>mful bact]ia 9 ! wat]4 ,/]iliz]s 9 :i* ultra-violet rays are ! active rays are n[ 9 use = ?is purpose1 be+ connect$ beyond ! outfl[ f ! filt]4 ,! effectiv5ess ( ! app>atus has be5 e/abli%$ by ! usual me?od ( c\nt+ ! bact]ia4 ,ne> ! outlet ( ! ord9>y filt] a c\nt reveal$ _m ?\s& bact]ia p] cubic in* ( wat] & among ^! !re 7 bact]ia ( inte/9al orig94 ,!n a /]iliz] 0 in/all$ 9 :i* ! effective elem5ts 7 two qu>tz m]cury-lamps :i* consum$ #b4b amp]es ea* at #bbj volts4 ,a c\nt ( bact]ia 9 ! wat] leav+ ! /]iliz] %[$ t ^! organisms _h be5 r$uc$ to #e p] c5t4 & f9ally to a small] p]c5tage ( _! orig9al value1 & t all ^? ( inte/9al orig9 _h be5 de/roy$4 ,9 fact1 ! wat] :i* 0 return$ to ! pool 0 bett] ?an t :i* mo/ p]sons dr9k4 ,radiant en]gy possesses advantages :i* are unequal$ by o!r bact]icidal ag5ts1 9 t x does n contam9ate or *ange ! prop]ties ( ! wat] 9 any way4 ,x does its "w ( de/roy+ bact]ia & leaves ! wat] o!rwise un*ang$4 ,^! glimpses ( ! use ( ! radiant en]gy z a means ( rega9+ & reta9+ good heal? sugge/ great] possibilities :5 ! facts become ?or\ghly e/abli%$ & correlat$4 ,! sun is ( prim>y importance to mank9d1 b x s]ves 9 s _m ways t x is naturally a compromise4 ,x _c supply j ! desir$ radiant en]gy = "o purpose & at ! same "t s]ve = ano!r purpose 9 ! be/ mann]4 ,x is obscur$ on cl\dy days & disappe>s nightly4 ,^! abs5ces are b5eficial to "s processes1 b man 9 ! highly organiz$ activity ( pres5t civilization desires radiant en]gy ( v>i\s qualities available at any "t4 ,9 ?is respect artificial light is sup]ior to ! sun & is be+ improv$ cont9ually4 ,,xxi ,,modify+ ,,artificial ,,light ,9 a s+le c5tury sci5ce has conv]t$ ! dimly light$ nights ) _! feeble flick]+ flames into artificial daytime4 ,9 ?is brief span ( ye>s ! production ( light has advanc$ f> f ! primitive flames 9 use at ! beg9n+ ( ! n9ete5? c5tury1 b1 z has be5 not$ 9 ano!r *apt]1 great improvem5ts 9 light-production are /ill possible4 ,nev]!less1 ! wond]ful developm5ts 9 ! la/ f\r decades1 :i* creat$ ! arc-lamps1 ! gas-mantle1 ! m]cury-vapor lamps1 & ! s]ies ( electric inc&esc5t-filam5t lamps1 h contribut$ mu* to ! effici5cy1 safety1 heal?1 & happ9ess ( mank9d4 ,a hundr$ ye>s ago civilization 0 m easily satisfi$ & an improvem5t :i* furni%$ m light at ! same co/ 0 all t c\ld be desir$4 ,to-day light alone is n suffici5t4 ,c]ta9 k9ds ( radiant en]gy are requir$ = photography & o!r photo*emical processes & a va/ array ( color$ light is dem&$ = displays & = effects ^u ! /age4 ,man n[ desires lights ( v>i\s colors = _! expressive effects4 ,he is no long] satisfi$ ) m]e light 9 adequate quantities2 he desires c]ta9 qualities4 ,fur!rmore1 he no long] f9ds x suffici5t to be indep5d5t ( daylight m]ely 9 quantity ( light4 ,9 fact1 he has dem&$ artificial daylight4 ,d\btless ! future w see ! production ( effici5t light ( _m qualities or colors1 b to-day _m ( ! dem&s mu/ be met by modify+ ! artificial illum9ants :i* are available4 ,vision is accompli%$ entirely by ! di/9ction ( brightness & color4 ,an image ( any sc5e or any object is focus$ ^u ! ret9a z a m9iature map 9 light1 %ade1 & color4 ,al?\gh ! di/9ction ( brightness is a m important function 9 vision ?an ! ability to di/+ui% colors1 color-vision is f> m important 9 daily life ?an is ord9>ily appreciat$4 ,"o may g ?r\gh life color-bl9d )\t suff]+ any great inconv5i5ce1 b ! div9e gift ( color-vision ca/s a magical drap]y ov] all creation4 ,relatively few are consci\s ( ! wond]ful drap]y ( color1 except = occasional mom5ts :5 ! display is unusual4 ,nev]!less a /udy ( vision 9 ne>ly all crafts reveals ! fact t ! di/9ction ( colors plays an important "p4 ,9 ! pur*ase ( food & we>+-app>el1 9 ! decoration ( homes & ?r\gh\t ! arts & indu/ries1 mank9d dep5ds a great deal ^u ! appe>ance ( colors4 ,he dep5ds ^u daylight 9 ?is respect & unconsci\sly (t51 :5 daylight fails1 ceases "w :i* dep5ds ^u ! accurate di/9ction ( colors4 ,8 color-vision evolv$ "u daylight2 arts & indu/ries develop$ "u daylight2 & all 8 associations ( color are bas$ prim>ily ^u daylight4 ,= ^! reasons1 adequate artificial illum9ation does n make mank9d indep5d5t ( daylight 9 ! practice ( arts & crafts & 9 _m m9or activities4 ,9 quality or spectral "*1 ! unmodifi$ illum9ants us$ = g5]al light+ purposes diff] f daylight & !re=e d n fully replace x4 ,noon sunlight conta9s all ! spectral colors 9 approximately ! same proportions1 b ?is is n true ( ^! artificial illum9ants4 ,= ^! reasons !re is a dem& = artificial daylight4 ,! vacuum tube af=ds a possibility ( an ext5sive v>iety ( illum9ants diff]+ widely 9 spectral "* or color4 ,e gas :5 excit$ to lum9esc5ce by an electric dis*>ge 9 ! vacuum tube 7conta9+ ! gas at a l[ pressure7 emits light ( a *>act]i/ic quality or color4 ,by v>y+ ! gas a v>iety ( illum9ants c be obta9$1 b ?is means ( light-production has n be5 develop$ to a suffici5tly practicable /ate to be satisfactory = g5]al light+4 ,nitrog5 yields a p9ki% light & ! nitrog5 tube z develop$ by ,dr4 ,moore 0 in/all$ to "s ext5t a few ye>s ago4 ,neon yields an orange light & has be5 us$ 9 a few cases = displays4 ,c>bon dioxide furni%es a :ite light simil> to daylight & small tubes conta9+ ?is gas are 9 use to-day :]e accurate discrim9ation ( color is ess5tial4 ,! flame-arcs af=d a means ( obta9+ a v>iety ( illum9ants diff]+ 9 spectral "* or color4 ,by impregnat+ ! c>bons ) v>i\s *emical comp\nds ! color ( ! flame c be widely alt]$4 ,! :ite flame-arc obta9$ by ! use ( r>e-e>? comp\nds 9 ! c>bons provides an illum9ant closely approximat+ av]age daylight4 ,by us+ v>i\s sub/ances besides c>bon = ! electrodes1 illum9ants diff]+ 9 spectral "* c be obta9$4 ,^! are usually ri* 9 ultra-violet rays & !re=e h _! be/ applications 9 processes dem&+ ?is k9d ( radiant en]gy4 ,! arc-lamp is limit$ 9 its application by its un/ead9ess1 its bulk9ess1 & ! impracticability ( subdivid+ x into light-s\rces ( a great range ( lum9\s int5sities4 ,! mo/ ext5sive applications ( artificial daylight h be5 made by means ( ! electric inc&esc5t filam5t lamp1 equipp$ ) a color$ glass :i* alt]s ! light to ! same quality z daylight4 ,! light f ! electric filam5t lamp is ri*] 9 yell[1 orange1 & r$ rays ?an daylight1 & by kn[+ ! spectral "* ( ! two illum9ants & ! spectral *>act]i/ics ( color$ glasses 9 :i* v>i\s *emicals h be5 incorporat$1 x is possible to develop a color$ glass :i* w filt] out ( ! excess ( yell[1 orange1 & r$ rays s t ! transmitt$ light is ( ! same spectral "* z daylight4 ,?\s&s ( su* artificial daylight units are n[ 9 use 9 ! indu/ries1 9 /ores1 9 laboratories1 9 dye-works1 9 pr9t-%ops1 & 9 _m o!r places4 ,curr5cy & ,lib]ty ,bonds h be5 made "u artificial daylight & su* units are 9 use 9 banks = ! detection ( c\nt]feit curr5cy4 ,! diamond exp]t detects ! color ( jewels & ! microscopi/ is c]ta9 ( ! colors ( 8 /a9s "u artificial daylight4 ,! dy] mixes 8 dyes = ! color+ ( tons ( valuable silk & ! arti/ pa9ts "u ?is artificial light4 ,^! are only a few ( a va/ numb] ( applications ( artificial daylight1 b !y illu/rate t mank9d is indep5d5t ( natural light 9 ano!r respect4 ,!re are v>i\s k9ds ( daylight1 two ( :i* are fairly con/ant 9 spectral "*4 ,^! are noon sunlight & nor? skylight4 ,! =m] may be said to be :ite light & its spectrum indicates ! pres5ce ( visible radiant en]gy ( all wave-l5g?s 9 approximately equal proportions4 ,nor? skylight conta9s an excess ( violet1 blue1 & blue-gre5 rays & z a consequ5ce is a blui% :ite4 ,noon sunlight on a cle> day is fairly con/ant 9 spectral "*1 b nor? skylight v>ies some:at dep5d+ ^u ! abs5ce or pres5ce ( cl\ds & ^u ! "* ( ! cl\ds4 ,if l>ge areas ( sunlit cl\ds are pres5t1 ! light is l>gely reflect$ sunlight4 ,if ! sky is ov]ca/1 ! nor? skylight is a result ( a mixture ( sunlight & blue skylight filt]$ ?r\gh ! cl\ds & is slightly blui%4 ,if ! sky is cle>1 ! light v>ies f light blue to deep blue4 ,illu/ration3 ,,fireworks ,,& ,,illum9at$ ,,battle-,,fleet ,,at ,,hudson-,,fulton ,,celebration ,illu/ration3 ,,fireworks ,,exhibition ,,on ,,may ,,day ,,at ,,panama-,,pacific ,,exposition ,! daylight :i* ent]s build+s is (t5 consid]ably alt]$ 9 color by reflection f o!r build+s & f vegetation1 & aft] x ent]s a room x is sometimes modifi$ by reflection f color$ surr\nd+s4 ,x may be commonly not$ t ! light reflect$ f gre5 grass ?r\gh a w9d[ to ! upp] "p ( a room is v mu* t9t$ ) gre5 & ! light reflect$ f a yell[ brick build+ is t9t$ yell[4 ,besides ^! alt]ations1 sunlight v>ies 9 color f ! yell[ or r$ ( dawn ?r\gh :ite at noon to orange or r$ at sunset4 ,?r\gh\t ! day ! am\nt ( light f ! sky does n *ange ne>ly z mu* z ! am\nt ( sunlight1 s !re is a cont9ual v>iation 9 ! proportion ( direct sunlight & skylight rea*+ ! e>?4 ,?is is fur!r v>i$ by ! *ang+ position ( ! sun4 ,= example1 at a nor? w9d[ 9 :i* ! direct sunlight may n ent] ?r\gh\t ! day1 ! am\nt ( sunlight :i* ent]s by reflection f adjac5t build+s & o!r objects may v>y greatly4 ,?us x is se5 t daylight n only v>ies 9 quantity b also 9 quality1 & an artificial daylight1 :i* is bas$ ^u an ext5sive analysis1 has ! advantage ( be+ con/ant 9 quantity & quality z well z correct 9 quality4 ,mod]n artificial-daylight units :i* h be5 sci5tifically develop$ n only make mank9d indep5d5t ( daylight 9 ! discrim9ation ( colors b !y are sup]ior to daylight4 ,al?\gh !re are _m exp]t colori/s :o require an accurate artificial daylight1 !re are va/ fields ( light+ :]e a less accurate daylight quality is necess>y4 ,! av]age eyes are n suffici5tly skill$ = ! f9e/ discrim9ation ( colors & !re=e ! ,mazda daylight lamp supplies ! less exact+ requirem5ts ( color mat*+4 ,x is a compromise betwe5 quality & effici5cy ( light & s]ves ! purpose s well t millions ( ^! lamps h f\nd applications 9 /ores1 (fices1 & indu/ries4 ,9 ord] to make an accurate artificial nor? skylight = color-"w by means ( color$ glass1 f #ge to #he p] c5t4 ( ! light f a tung/5 lamp mu/ be filt]$ out4 ,?is absorption 9 a broad s5se increases ! effici5cy ( ! light1 = ! fraction t rema9s is n[ satisfactory1 :]eas ! orig9al light is virtually useless = accurate color-discrim9ation4 ,ab\t "o ?ird ( ! orig9al light is absorb$ by ! bulb ( ! tung/5 daylight lamp1 ) a resultant light :i* is an approximation to av]age daylight4 ,old illum9ants su* z t emitt$ by ! c&le & oil-lamp 7 us$ = c5turies 9 int]iors4 ,all ^! illum9ants 7 ( a w>m yell[ color4 ,ev5 ! e>li] mod]n illum9ants 7 n v diff]5t 9 color1 s x is n surpris+ t !re is a deeply root$ desire = artificial light 9 ! home & 9 simil> int]iors ( a w>m yell[ color simulat+ t ( old illum9ants4 ,! psy*ological effect ( w>m? & *e]fulness due to su* illum9ants or colors is well e/abli%$4 ,artificial light 9 ! home symbolizes indep5d5ce ( nature & protection f ! elem5ts & !re is a firm desire to c\nt]act ! increas+ :it5ess ( mod]n illum9ants by means ( %ades ( a w>m t9t4 ,! :ite light is excell5t = ! kit*51 laundry1 & ba?-room1 & = read+-lamps1 b ! w>m yell[ light is be/ suit$ = mak+ cozy & *e]ful ! environm5t ( ! int]iors 9 :i* mank9d relaxes4 ,an illum9ant ( ?is "* c be obta9$ effici5tly by us+ a prop]ly t9t$ bulb on tung/5 filam5t lamps4 ,by absorb+ ab\t "o f\r? to "o ?ird ( ! light 7dep5d+ ^u ! temp]ature ( ! filam5t7 ! color ( ! c&le flame may be simulat$ by means ( a tung/5 filam5t lamp4 ,"s p]sons are /ill us+ ! c>bon-filam5t lamp despite its l[ effici5cy1 because !y desire to reta9 ! w>m? ( t9t ( ! old] illum9ants4 ,h[ev]1 light f a tung/5 lamp may be filt]$ to obta9 ! same quality ( light z is emitt$ by ! c>bon filam5t lamp by absorb+ f "o fif? to "o f\r? ( ! light4 ,! lum9\s effici5cy ( ! tung/5 lamp equipp$ ) su* a t9t$ bulb is /ill ab\t twice z great z t ( ! c>bon-filam5t lamp4 ,?us ! high effici5cy ( ! mod]n illum9ants is utiliz$ to advantage ev5 ?\gh _! color is ma9ta9$ ! same z ! old illum9ants4 ,all mod]n illum9ants emit radiant en]gy1 :i* does n affect ! ord9>y photographic plate4 ,?is sup]flu\s visible en]gy m]ely contributes t[>d gl>e or a sup]abundance ( light 9 photographic /udios4 ,a glass has be5 develop$ :i* transmits virtually all ! rays t affect ! ord9>y photographic plate & greatly r$uces ! accompany+ inactive rays4 ,su* a glass is naturally blue 9 color1 because x mu/ transmit ! blue1 violet1 & ne> ultra-violet rays4 ,its d5sity has be5 s det]m9$ = use 9 bulbs = ! high-effici5cy tung/5 lamps t ! resultant light appe>s approximately ! color ( skylight )\t sacrific+ an appreciable am\nt ( ! value ( ! radiant en]gy = ord9>y photography4 ,?is glass1 x is se51 transmits ! s-call$ *emical rays & is useful 9 o!r activities :]e ^! rays alone are desir$4 ,x is us$ 9 light-!rapy & 9 "s o!r activities 9 :i* ! *emical effects ( ^! rays are utiliz$4 ,9 ! photographic d>k-room a deep r$ light is safe = all emulsions except+ ! pan*romatic1 & lamps ( ?is "* are /&>d products4 ,an orange light is safe = _m pr9t+ pap]s4 ,pan*romatic plates & films are usually develop$ 9 ! d>k :]e extreme safety is desir$1 b a v weak deep r$ light is n unsafe if us$ cauti\sly4 ,h[ev]1 _m photographic emulsions ( ?is "* are n v s5sitive to gre5 rays1 s a gre5 light has be5 us$ = ?is purpose4 ,a v>iety ( color$ lights are 9 dem& = !atrical effects1 displays1 spectacul> light+1 signal+1 etc41 & !re are _m sup]ficial color+s available = ?is purpose4 ,few ( ^! %[ any appreciable degree ( p]man5cy4 ,p]man5t sup]ficial color+s h rec5tly be5 develop$1 b ^! are secret processes unavailable = ! m>ket4 ,= ?is reason color$ glass is ! only m$ium g5]ally available :]e p]man5cy is desir$4 ,= p]man5t light+ effects1 signal glasses1 color$ caps1 & %eets ( color$ glass may be us$4 ,t9ts may be obta9$ by means ( color$ reflectors4 ,o!r color$ m$ia are dyes 9 lacqu]s & 9 v>ni%es1 color$ inks1 color$ textiles1 & color$ pigm5ts4 ,inasmu* z color$ glass ent]s into ! developm5t ( p]man5t devices1 x may be ( int]e/ to discuss briefly ! effects ( v>i\s metallic comp\nds :i* are us$ 9 glass4 ,! exact color produc$ by ^! comp\nds1 :i* are (t5 oxides1 v>ies slightly ) ! composition ( ! glass & me?od ( manufacture1 b ?is phase is only ( te*nical int]e/4 ,! color+ sub/ances 9 glass may be divid$ into two gr\ps4 ,! fir/ & l>ge/ gr\p consi/s ( ^? 9 :i* ! color+ matt] is 9 true solution2 t is1 ! color+ is produc$ 9 ! same mann] z ! color+ ( wat] 9 :i* a *emical salt is dissolv$4 ,9 ! second gr\p ! color+ sub/ances are pres5t 9 a f9ely divid$ or colloidal /ate2 t is1 ! color+ is due to ! pres5ce ( p>ticles 9 me*anical susp5sion4 ,9 g5]al1 ! light] elem5ts d n t5d to produce color$ glasses1 b ! heavi] elem5ts 9 s f> z !y c be incorporat$ into glass t5d to produce int5se colors4 ,( c\rse1 !re are exceptions to ?is g5]al /atem5t4 ,! alkali metals1 su* z sodium1 potassium1 & li?ium1 d n color glass appreciably1 b !y h indirect effects ^u ! colors produc$ by manganese1 nickel1 sel5ium1 & "s o!r elem5ts4 ,gold 9 suffici5t am\nts produces a r$ 9 glass & 9 l[ conc5tration a beautiful rose4 ,x is pres5t 9 ! colloidal /ate4 ,9 ! manufacture ( gold r$ glass1 ! glass :5 fir/ cool$ %[s no color1 b on reheat+ ! ri* ruby color develops4 ,! glass is !n cool$ sl[ly4 ,! gold is left 9 a colloidal /ate4 ,copp] :5 add$ to a glass produces two colors1 blue-gre5 & r$4 ,! blue-gre5 color1 :i* v>ies 9 diff]5t k9ds ( glasses1 results :5 ! copp] is fully oxidiz$1 & ! r$ by prev5t+ oxidation by ! pres5ce ( a r$uc+ ag5t4 ,?is r$ may be develop$ by reheat+ z 9 ! case ( mak+ gold ruby glass4 ,sel5ium produces orange & r$ colors 9 glass4 ,silv] :5 appli$ to ! surface ( glass produces a beautiful yell[ color & x has be5 widely us$ 9 ?is mann]4 ,x has little color+ effect 9 glass1 because x is s readily r$uc$1 result+ 9 a metallic black4 ,uranium produces a can>y yell[ 9 soda & pota%-lime glasses1 :i* fluoresce1 & ^! glasses may be us$ 9 ! detection ( ultra-violet rays4 ,! color is topaz 9 lead glass4 ,bo? sulphur & c>bon are us$ 9 ! manufacture ( pale yell[ glasses4 ,antimony has a weak effect1 b 9 ! pres5ce ( mu* lead x is us$ = mak+ opaque or transluc5t yell[ glasses4 ,*romium produces a gre5 color1 :i* is r$di% 9 lead glass1 & yell[i% 9 soda1 & pota%-lime glasses4 ,iron imp>ts a gre5 or blui% gre5 color to glass4 ,x is usually pres5t z an impurity 9 ! +r$i5ts ( glass & its color is neutraliz$ by add+ "s manganese1 :i* produces a purple color complem5t>y to ! blui% gre54 ,?is acc\nts = ! manganese purple :i* develops f colorless glass expos$ to ultra-violet rays4 ,iron is us$ 9 bottle gre5 glass4 ,its color is gre5i% blue 9 pota%-lime glass1 blui% gre5 9 soda-lime glass1 & yell[i% gre5 9 lead glass4 ,cobalt is widely us$ 9 ! production ( blue glasses4 ,x produces a violet-blue 9 pota%-lime & soda-lime glasses & a blue 9 lead glasses4 ,x appe>s blue1 b x transmits deep r$ rays4 ,= ?is reason :5 us$ 9 conjunction ) a deep r$ glass1 a filt] = only ! deepe/ r$ rays is obta9$4 ,nickel produces an ame?y/ color 9 pota%-lime glass1 a r$di% br[n 9 soda-lime glass1 & a purple 9 lead glass4 ,manganese is us$ l>gely z a decoloriz+ ag5t 9 c\nt]act+ ! blue-gre5 ( iron4 ,x produces an ame?y/ color 9 pota%-lime glass & r$di% violet 9 soda-lime & lead glasses4 ,^! are ! pr9cipal color+ +r$i5ts us$ 9 ! manufacture ( color$ glass4 ,! /a9+ ( glass is done "u l[] temp]atures1 s t a great] v>iety ( *emical comp\nds may be us$4 ,! result+ colors ( metals & metallic oxides dissolv$ 9 glass dep5d n only ^u ! nature ( ! metal us$1 b also p>tly ^u ! /age ( oxidation1 ! composition ( ! glass & ev5 ^u ! temp]ature ( ! fusion4 ,9 develop+ a glass filt] ! effects ( ! v>i\s color+ elem5ts are det]m9$ spectrally & ! v>i\s elem5ts are v>i$ 9 prop] proportions until ! glass ( desir$ spectral transmission is obta9$4 ,x is se5 t ! color+ elem5ts are limit$ & ! comb9ation ( ^! is fur!r limit$ by *emical consid]ations4 ,9 comb9+ v>i\s color$ glasses or v>i\s color+ elem5ts 9 ! same glass ! subtractive me?od ( color-mixture is utiliz$4 ,= example1 if a gre5 glass is desir$1 yell[i% gre5 *romium glass may be us$ z a basis4 ,by ! addition ( "s blue-gre5 due to copp]1 ! yell[ rays may be fur!r subdu$ s t ! result+ color is gre54 ,! prim>y colors = ?is me?od ( color-mixture are ! same z ^? ( ! pa9t] 9 mix+ pigm5ts--namely1 purple1 yell[1 & blue-gre54 ,v>i\s colors may be obta9$ by sup]pos+ or intimately mix+ ! colors4 ,! result+ transmission 7reflection 9 ! case ( reflect+ m$ia su* z pigm5ts7 are ^? colors commonly transmitt$ by all ! compon5ts ( a mixture4 ,?us1 ,purple & yell[ r$ ,yell[ & blue-gre5 gre5 ,blue-gre5 & purple blue ,! colors produc$ by add+ lights are bas$ n on ! subtractive me?od b on ! actual addition ( colors4 ,^! prim>ies are r$1 gre51 & blue & x w be not$ t !y are ! complem5t>ies ( ! subtractive prim>ies4 ,by ! use ( r$1 gre51 & blue lights 9 v>i\s proportions1 all colors may be obta9$ 9 v>y+ degrees ( purity4 ,! *ief mixtures ( two ( ! additive prim>ies produce ! subtractive prim>ies4 ,?us1 ,r$ & blue purple ,r$ & gre5 yell[ ,gre5 & blue blue-gre5 ,al?\gh ! color+ m$ia :i* are p]man5t "u ! action ( light1 heat1 & moi/ure are relatively few1 by a k ( _! spectral *>act]i/ics & o!r pr9ciples ( color ! exp]t is able to produce _m p]man5t colors = light+ effects4 ,! additive & subtractive me?ods are *iefly involv$1 b !re is ano!r me?od :i* is an av]ag+ additive "o4 ,= example1 if a w>m t9t ( yell[ is desir$ & only a d5se yell[ glass is available1 ! yell[ glass may be cut into small pieces & arrang$ ^u a colorless glass 9 *eck]-bo>d fa%ion4 ,?us a great deal ( uncolor$ light :i* is transmitt$ by ! filt] is slightly t9t$ by ! yell[ light pass+ ?r\gh ! pieces ( yell[ glass4 ,if ?is light is prop]ly mix$ by a diffus+ glass ! effect is satisfactory4 ,^! are ! pr9cipal means ( obta9+ color$ light by means ( filt]s & by mix+ color$ lights4 ,by us+ ^! 9 conjunction ) ! array ( light-s\rces available x is possible to meet mo/ ( ! gr[+ dem&s4 ,( c\rse1 ! ideal solution is to make ! color$ light directly at ! light-s\rce1 & d\btless future developm5ts :i* n[ appe> remote or ev5 impossible w supply su* color$ illum9ants4 ,9 ! meantime1 mu* is be+ accompli%$ ) ! means available4 ,,xxii ,,spectacul> ,,light+ ,artificial light is a natural ag5cy = produc+ spectacul> effects4 ,x is readily controll$ & alt]$ 9 color & ! brightness :i* x l5ds to displays outdoors at night r5d]s !m extremely conspicu\s aga9/ ! d>kness ( ! sky4 ,x surpasses o!r decorative m$ia by ! extreme range ( values :i* may be obta9$4 ,! decorator & pa9t] are limit$ by a range ( values f black to :ite pigm5ts1 :i* ord9>ily repres5ts an extreme contra/ ( ab\t "o to ?irty4 ,! brightnesses due to light may v>y f d>kness to ^? ( ! light-s\rces !mselves4 ,! decorator deals ) second>y light--t is1 light reflect$ by m or less diffusely reflect+ objects4 ,! light+ exp]t has at 8 comm& n only ?is second>y light b ! prim>y light ( ! s\rces4 ,light+ effects ev]y:]e attract att5tion & ev5 ! mod]n m]*ant te/ifies t adequate light+ 9 8 /ore is ( adv]tis+ value4 ,9 all ! field ( spectacul> light+ ! sup]iority ( artificial light ov] natural light is demon/rat$4 ,light is a univ]sal m$ium ) :i* to attract att5tion & to en?rall mank9d4 ,! civilizations ( all ages h realiz$ ?is natural p[] ( light4 ,x has play$ a "p 9 ! fe/ivals & triumphal processions f "t immemorial & is /ill ! mo/ important feature ( _m celebrations4 ,9 ! e>ly fe/ivals fires1 c&les1 & oil-lamps 7 us$ & fireworks 7 inv5t$ = ! purpose4 ,ev5 to-day ! pyrote*nical displays aga9/ ! d>k dep?s ( ! night sky hold mank9d spellb\nd4 ,b ^! evanesc5t notes ( light h be5 improv$ ^u by m p]man5t displays on a huge scale4 ,?irty ye>s be=e ! fir/ practical in/allation ( gas-light+ an exhibition ( ,philosophical ,fireworks produc$ by ! combu/ion ( inflammable gases 0 giv5 9 sev]al cities ( ,engl&4 ,x is a long /ep f ! array ( flick]+ gas-flames ) :i* ! fronts ( ! build+s ( ! ,soho works 7 illum9at$ a c5tury ago to ! wond]ful light+ effects a c5tury lat] at ! ,panama-,pacific ,exposition4 ,"s :o saw t orig9al display ( gas-jets total+ a few hundr$ c&le-p[] describ$ x z an occasion ( extraord9>y spl5d\r4 ,:at w\ld !y h said ( ! mod]n spectacul> light+ at ! ,exposition :]e ,ryan us$ 9 a s+le effect =ty-eight l>ge se>*-lights aggregat+ #b1fjj1jjj1jjj beam c&le-p[]6 ,no o!r comp>ison exemplifies m /rik+ly ! progress ( artificial light+ 9 ! hundr$ ye>s :i* h elaps$ s9ce x began to be develop$4 ,! nature ( ! light-s\rces 9 ! fir/ half ( ! n9ete5? c5tury did n enc\rage spectacul> or display light+4 ,9 fact1 ?is phase ( light+ *iefly develop$ along ) electric lamps4 ,( c\rse1 occasionally "s tempor>y effect 0 attempt$ z 9 ! case ( illum9at+ ! dome ( ,/4 ,paul's ,ca!dral 9 ,london 9 #ahgb1 b cont9u$ op]ation ( ! display 0 n ent]ta9$4 ,9 ! case ( light+ ?is dome a l>ge numb] ( %ip's lant]ns 7 us$1 b ! result 0 unsatisfactory4 ,aft] ?is unsuccessful attempt at light+ ,/4 ,paul's1 a sugge/ion 0 made ( flood+ x ) electric light project$ f v>i\s qu>t]s4 ,spectacul> light+ outdoors really began 9 e>ne/ 9 ! dawn ( ! tw5tie? c5tury4 ,al?\gh "s ( ! fir/ attempts at spectacul> light+ outdoors 7 made ) se>*-lights1 spectacul> light+ did n become g5]ally popul> until ! appe>ance ( inc&esc5t filam5t lamps ( reasonable effici5cy & co/4 ,! effects 7 obta9$ prim>ily by ! use ( small electric filam5t lamps drap$ 9 fe/oons or in/all$ along ! outl9es & o!r pr9cipal l9es ( build+s & monum5ts4 ,! effect 0 almo/ :olly t ( light1 = ! gl>e f ! visible lamps obscur$ ! build+s or o!r objects4 ,! me?od is /ill us$ because x is simple & ! effects may be p]man5tly in/all$ )\t requir+ any att5tion except+ to replace burn$-out lamps4 ,h[ev]1 ! me?od has limitations f an arti/ic po9t ( view because ! arti/ic effects ( pa9t+1 sculpture1 & ar*itecture _c be comb9$ ) x v effectively4 ,= example1 ! details ( a monum5t or ( a build+ _c be se5 di/9ctly en\gh to be appreciat$4 ,! effect is m]ely t ( outl9es or l9es & patt]ns ( po9ts ( light & is usually gl>+4 ,! next /ep 0 to conceal ^! lamps beh9d ! cornices or o!r projections or 9 nooks con/ruct$ ! purpose4 ,light n[ began to mold & to pa9t ! objects4 ,! /ructures began to be visible2 at lea/ ! important cornices & o!r details 7 no long] m]e outl9es4 ,! introduction ( ! drawn-wire tung/5 lamp is responsible = an innovation 9 spectacul> light+ ( ?is sort1 = n[ x became possible to make conc5trat$ light-s\rces s ess5tial to projectors4 ,fur!rmore1 ^! light+ units require v little att5tion aft] once be+ locat$4 ,) ! introduction ( electric-filam5t lamps ( ?is "* small projectors came into use1 & by means ( conc5trat$ beams ( light :ole build+s & monum5ts c\ld be flood$ ) light f remote positions4 ,! effects obta9$ by conceal+ lamps beh9d cornices _h demon/rat$ t ! light+ ( ! surfaces 0 ! object to be realiz$ 9 mo/ cases1 & :5 small projectors n requir+ con/ant att5tion became available1 a great impetus 0 giv5 to flood-light+4 ,:5 ,france gave to ?is c\ntry ! ,b>?oldi ,/atue ( ,lib]ty !re 0 no ?\ght ( hav+ ?is emblem visible at night except+ = ! tor* held ! h& ( ,lib]ty4 ,?is tor* 0 modifi$ at ! "t ( ! erection ( ! /atue to accommodate ! lamps available1 ) ! result t x 0 m]ely a lant]n conta9+ a numb] ( electric lamps4 ,at night x 0 a speck ( light m feeble ?an _m surr\nd+ %ore lights4 ,! /atue _h be5 light$ dur+ fe/ivals ) fe/oons & outl9es ( lamps1 b 9 #aiae1 :5 ! fre$om ( ! g5]\s donor ( ! /atue appe>$ to be at /ake1 a movem5t 0 begun :i* culm9at$ 9 a fund = flood-light+ ,lib]ty4 ,! broad f\ndation ( ! /atue made ! light+ comp>atively easy by means ( banks ( inc&esc5t filam5t se>*-lights4 ,ab\t #bbe ( ^! units 7 us$ ) a total beam c&le-p[] ( ab\t #bj1jjj1jjj4 ,! orig9al idea ( an imitation flame = ! tor* 0 re/or$ by build+ ?is f pieces ( yell[ ca!dral glass ( ?ree d5sities4 ,ab\t six hundr$ pieces ( glass 7 us$1 ! upp] ones be+ g5]ally ( ! light] t9ts & ! l[] ones ( ! d>k] t9ts4 ,a ligh?\se l5s 0 plac$ 9 ?is lant]n s t an int5se beam ( light w\ld radiate f x4 ,! flood-light$ ,/atue ( ,lib]ty is n[ visible by night z well z by day & x has a d\ble significance at night1 = light also symbolizes indep5d5ce4 ,j z ! ,/atue ( ,lib]ty /&s alone 9 ! ,new ,york ,h>bor s does ! ,woolwor? ,build+ reign supreme on l[] ,manhattan4 ,lib]ty proclaims indep5d5ce f ! bondage ( man & ! ,woolwor? ,t[] /&s maje/ically 9 defiance ( ! elem5ts z a symbol ( man's gr[+ indep5d5ce ( nature4 ,?is build+ ) its cream t]ra-cotta surface & intricate ar*itectural details t\*$ "h & !re ) buff1 blue1 gre51 r$1 & gold1 rises #gib feet or sixty /ories above ! /reet & typifies ! ,am]ican _s ( conceiv+ & ( execut+ great und]tak+s4 ,9 x are bl5d$ art1 utility1 & maje/y4 ,view$ by multitudes dur+ ! day1 x is a valuable adv]tisem5t = ! "n :i* /&s = a national in/itution4 ,b by day x %>es att5tion ) its surr\nd+s4 ,if light$ at night x w\ld /& virtually alone aga9/ ! d>k sky & ! inve/m5t w\ld n be :olly idle dur+ ! ev5+ h\rs4 ,mr4 ,h4 ,h4 ,magdsick1 :o design$ ! light+ = ,lib]ty1 plann$ ! light+ = ! ,woolwor? ,t[]1 :i* rises #djg feet or ?irty-"o /ories above ! ma9 build+4 ,five hundr$ & fifty projectors conta9+ tung/5 filam5t lamps 7 di/ribut$ ab\t ! base ( ! t[] & among "s ( ! ar*itectural details4 ,! ma9 ar*itectural features ( ! mans>d ro( ext5d+ f ! fifty-?ird to ! fifty-sev5? floor1 ! obs]vation balcony at ! fifty-eigh? & ! lant]n /ructures at ! fifty-n9? & sixtie? floors are cov]$ ) gold-leaf4 ,by prop] plac+ ( ! projectors a glitt]+ effect is obta9$ f ^! gold surfaces4 ,! cr[n+ features ( ! light+ effect are ! lant]ns 9 ! cre/ ( ! spire4 ,tw5ty-f\r #ajjj-watt tung/5 lamps 7 plac$ beh9d cry/al diffus+ glass1 :i* transmits ! light pr$om9antly 9 a horizontal direction4 ,?us at long di/ances1 f :i* ! ar*itectural details _c be di/+ui%$1 ! brilliant cr[n+ light is visible4 ,an automatic dimm] 0 devis$ s t ! effect ( a huge v>y+ flame 0 obta9$4 ,at close range1 ow+ to ! nature ( ! glass panels1 ?is portion is n mu* bright] ?an ! rema9d] ( ! surfaces4 ,:5 ! artificial light+ is 9 op]ation ! t[] becomes a maje/ic spire ( light & ?is magnific5t ,go?ic /ructure project+ defiantly into ! dep?s ( d>kness is 9 m ?an "o s5se a tor* ( mod]n civilization4 ,_m prom95t build+s & monum5ts h bur/ =? 9 a flood ( light1 & _! beauty & symbolism h be5 appreciat$ at night by _m p]sons :o d n notice !m by day4 ,n only are ! beautiful /ructures ( man light$ p]man5tly b _m tempor>y effects are devis$4 ,artificial light+ effects h become a prom95t "p 9 outdoor fe/ivals1 pageants1 & !atricals4 ,c&les h be5 associat$ ) ,*ri/mas trees ev] s9ce ! latt] came into use & naturally artificial light has be5 a feature 9 ! community ,*ri/mas trees :i* h come into vogue 9 rec5t ye>s4 ,! ,municipal ,*ri/mas ,tree 9 ,*icago 9 #aiaf 0 n9ety feet high & 0 light$ ) projectors4 ,?\s&s ( gems tak5 f ! ,t[] ( ,jewels at ! ,san ,francisco ,exposition add$ life & sp>kle to t ( ! o!r decorations4 ,illu/ration3 ,! ,capitol flood$ ) light ,luna ,p>k1 ,coney ,isl&1 /udd$ ) #fj1jjj inc&esc5t filam5t lamps ,,! ,,new ,,flood ,,light+ ,,contra/$ ,,) ,,! ,,old ,,outl9e ,,light+ ,illu/ration3 ,,niag>a ,,falls ,,flood$ ,,) ,,light ,aft] ! close ( ! rec5t w> artificial light play$ a prom95t "p ?r\gh\t ! c\ntry 9 ! joyful fe/ivals4 ,a jewel$ ar* erect$ 9 ,new ,york 9 honor ( ! return+ soldi]s rival$ "s ( ! spectacles ( ! ,panama-,pacific ,exposition4 ,! ar* hung l a gigantic curta9 ( jewels betwe5 two obelisks1 :i* rose to a height ( eighty feet & 7 surm\nt$ by jewel$ =ms 9 ! %ape ( sunbur/s4 ,approximately ?irty ?\s& jewels glitt]$ 9 ! beams ( batt]ies ( arc-projectors4 ,_m ( ! signs & devices :i* play$ a "p 9 ! ,welcome ,home movem5t 7 ( /rik+ nature & ( a "* to indicate p]man5cy4 ,! equipm5t ( a l>ge build+ consi/$ ( m ?an five ?\s& #aj-watt lamps1 ! entire build+ be+ outl9$ ) />s consi/+ ( elev5 lamps ea*4 ,! ,bright5 ,up campaign spread ?r\gh\t ! c\ntry4 ,! light+ & in/allation ( signs & special patriotic displays1 ! flood+ ( /reets & %op-w9d[s ) light )\t /9t1 produc$ an inspir+ & uplift+ effect :i* did mu* to re/ore *e]fulness & optimism4 ,a gl[+ example 0 set 9 ,wa%+ton1 :]e ! flood-light+ ( ! ,capitol1 discont9u$ %ortly aft] our entrance into ! w>1 0 resum$4 ,9 ,*icago a ,victory ,way 0 e/abli%$1 ) /reet-light+ po/s on bo? sides ( ! /reet equipp$ ) r$1 :ite1 & blue globes surm\nt$ by a gold5 goddess ( ,victory4 ,"o hundr$ & sev5ty-five projectors 7 in/all$ along ! way on ! ro(s & 9 ! w9d[s ( (fice build+s4 ,a brilliant1 sc9tillat+ ,alt> ( ,victory 0 erect$ at ! c5t] ( ! ,way4 ,x 0 compos$ ( two enorm\s c&elabra erect$ "o on ea* side ( a plat=m n9ety feet high4 ,^! 7 /udd$ ) jewels & support$ a curta9 ( jewels susp5d$ f ! alt>4 ,9 ! c5t] ( ! curta9 0 a huge jewel$ eagle be>+ ! ,alli$ flags4 ,?is 0 illum9at$ by arc-projectors :i* deliv]$ #bjj1jjj1jjj beam c&le-p[]4 ,9 addition to ^! !re 7 _m small] projectors4 ,9 ! top ( ea* c&elabra six l>ge r$-&-orange lamps 7 in/all$ 9 reflectors4 ,^! illum9at$ live /eam :i* issu$ f ! top4 ,surm\nt+ ! :ole 0 a huge lum9\s fan =m$ by beams f l>ge arc se>*-lights4 ,^! are only a few ( ! _m light+ effects :i* welcom$ ! return+ soldi]s1 b !y illu/rate h[ mu* mod]n civilization dep5ds ^u artificial light = express+ its feel+s & emotions4 ,?r\gh\t all ^! fe/ivals light sil5tly symboliz$ happ9ess1 fre$om1 & advancem5t4 ,projectors 7 us$ on a l>ge scale 9 sev]al cases be=e ! adv5t ( ! conc5trat$ filam5t lamp4 ,w4 ,d',a4 ,ryan1 ! lead] 9 spectacul> light+1 light$ ! ,niag>a ,falls 9 #aijg ) batt]ies ( arc-projectors aggregat+ #a1aae1jjj1jjj-;beam c&le-p[]4 ,9 #aijh he us$ ?irty arc-projectors to flood ! ,s+] ,t[] 9 ,new ,york ) light & project$ light to ! flag on top by means ( a se>*-light ?irty in*es 9 diamet]4 ,_m flags wav$ ?r\gh\t ! w> 9 ! beams ( se>*-lights1 symboliz+ a patriotism fully ar\s$4 ,! se>*-light beam z x bores ?r\gh ! atmosph]e at night is usually fa9tly bright1 ow+ to ! small am\nt ( fog1 du/1 & smoke 9 ! air4 ,by provid+ m sub/ance 9 ! atmosph]e1 ! beams are made to appe> bright]4 ,foll[+ ?is reason+1 ,ryan develop$ 8 sc9tillator consi/+ ( a batt]y ( se>*-light beams project$ upw>d ?r\gh cl\ds ( /eam :i* provid$ an artificial fog4 ,?is 0 fir/ display$ at ! ,hudson-,fulton celebration ) a batt]y ( arc se>*-lights total+ #a1jjj1jjj1jjj-;c&le-p[]4 ,all ^! effects despite _! magnitude 7 dw>f$ by ^? at ! ,panama-,pacific ,exposition1 & inasmu* z ?is up to ! pres5t "t repres5ts ! cr[n+ a*ievem5t 9 spectacul> light+1 "s ( ! details work$ out by ,ryan may be ( int]e/4 ,9 g5]al1 ! light+ effects dep>t$ f ! biz>re outl9e light+ 9 :i* gl>+ light-s\rces /udd$ ! /ructures4 ,! radiant gr&eur & beauty ( flood-light+ f conceal$ light-s\rces 0 ! key-note ( ! light+4 ,9 ?is mann] wond]ful effects 7 obta9$1 :i* n only appeal$ to ! eye & to ! arti/ic s5sibility b :i* 7 free f gl>e4 ,by means ( flood-light+ & relief-light+ f conceal$ light-s\rces ! ?ird dim5sion or dep? 0 obta9$ & ! ar*itectural details & color+s 7 pres]v$4 ,a great _m diff]5t k9ds ( devices & lamps 7 us$ to make ! night effects sup]ior 9 gr&eur to ^? ( daytime4 ,! ,zone or amusem5t section 0 light$ ) b>e lamps 9 ! old] mann] & ! gl>+ biz>re effects contra/$ ! spectacul> light+ ( ! pa/ ) ! illum9ation ( ! future4 ,9 ano!r section ! visitor 0 greet$ ) a gorge\s display ( c>nival _s4 ,beautifully color$ h]aldic %ields on :i* 7 writt5 ! e>ly hi/ory ( ! ,pacific coa/ 7 illum9at$ by gr\ps ( lum9\s arc-lamps on /&>ds v>y+ f tw5ty-five to fifty-five feet 9 height4 ,! ,t[] ( ,jewels ) m ?an a hundr$ ?\s& dangl+ gems 0 flood-light$1 & ! myriads ( m9ute reflect$ images ( light-s\rces glitt]+ aga9/ ! d>k sky produc$ an effect surpass+ ! dreams ( imag9ation4 ,%ad[s & high-lights ( /rik+ contra/s or ( elusive colors greet$ ! visitor on e h&4 ,individual isolat$ effects ( light 7 to be f\nd "h & !re4 ,fire hiss$ f ! m\?s ( s]p5ts & ca/ ! spell ( mobile light ov] ! composite ,spani%-,go?ic-,ori5tal sett+4 ,a color$ beam ( a se>*-light play$ "h & !re4 ,my/]i\s vapors ris+ f caldrons 7 9 reality illum9at$ /eam4 ,symbolic f\nta9 gr\ps did n escape ! magic t\* ( ! light+ wiz>d4 ,9 ! ,c\rt ( ! ,univ]se great areas 7 illum9at$ by two f\nta9s ris+ ab\t a hundr$ feet above ! sunk5 g>d5s4 ,"o ( ^! symboliz$ ! sett+ sun1 ! o!r ! ris+ sun4 ,! %aft & ball at ! cre/ ( ea* f\nta9 7 glaz$ ) heavy opal glass imitat+ trav]t9e m>ble & 9 ^! 7 in/all$ inc&esc5t lamps ( a total c&le-p[] ( #ejj1jjj4 ,! balu/rade sev5ty feet above ! sunk5 g>d5s 0 surm\nt$ by ne>ly two hundr$ inc&esc5t filam5t se>*-lights4 ,light 0 ev]y:]e1 ei!r v>y+ 9 color into a h>moni\s sc5e or *ang+ 9 light & %ad[ to mold ! ar*itecture & sculpture4 ,! enorm\s glass dome ( ! ,palace ( ,horticulture 0 conv]t$ into an a/ronomical sph]e by project+ images ^u x 9 su* a mann] t spots ( light revolv$2 r+s & comets :i* appe>$ at ! horizon pass$ on _! way ?r\gh ! heav5s1 *ang+ 9 color & disappe>+ aga9 at ! horizon4 ,all ^! effects & _m m 7 mirror$ 9 ! wat]s ( ! lagoons & ! :ole 0 a ,wond]l& inde$4 ,! sc9tillator consi/$ ( #dh arc se>*-lights ?ree feet 9 diamet] total+ #b1fjj1jjj1jjj beam c&le-p[]4 ,! light+ units 7 equipp$ ) color$ scre5s & ! beams :i* radiat$ upw>d 7 suppli$ ) an artificial fog by means ( /eam g5]at$ by a mod]n express locomotive4 ,! latt] 0 s arrang$ t ! :eels c\ld be driv5 at a spe$ ( sixty miles p] h\r "u brake1 !reby emitt+ great volumes ( /eam & smoke1 :i* :5 illum9at$ ) v>i\s colors produc$ a magnific5t spectacle4 ,ov] ?ree hundr$ sc9tillator effects 7 work$ out & ?is feature ( fireless fireworks 0 widely v>i$4 ,! aurora borealis & o!r effects creat$ by ?is batt]y ( se>*-lights ext5d$ = _m miles4 ,! _m effects regul>ly available 7 augm5t$ on special occasions & x is safe to /ate t ?is app>atus built ^u a huge scale provid$ a flexibility ( fireless fireworks nev] atta9$ ev5 ) small-scale devices4 ,! light+ ( ! exposition c b>ely be t\*$ ^u 9 a few p>agraphs & x w\ld be difficult to describe 9 words ev5 if space 7 unlimit$4 ,x repres5t$ ! p[] ( light to beautify & to awe4 ,x %[$ ! feebl5ess ( ! decorator's m$ia 9 comp>ison ) light pulsat+ ) life4 ,x consi/$ ( a great v>iety ( direct1 mask$1 conceal$1 & project$ effects1 b ^! 7 bl5d$ h>moni\sly ) "o ano!r & ) ! decorative & ar*itectural details ( ! /ructures4 ,x 0 a cr[n+ a*ievem5t ( a c5tury ( public light+ :i* began ) ,murdock's initial display ( a hundr$ flick]+ gas-jets4 ,x demon/rat$ ! p[]s ( sci5ce 9 ! production ( light & ( g5ius & imag9ation 9 ! utilization ( light4 ,x 0 a sil5t b pulsat+ display ( gr&eur dw>f+ into insignificance ! aurora borealis 9 its mo/ respl5d5t mom5ts4 ,,xxiii ,,! ,,expressiv5ess ,,( ,,light ,f an e/hetic or1 m broadly1 a psy*ological po9t ( view no m$ium rivals light 9 expressiv5ess4 ,n only is light alli$ ) man's mo/ important s5se b ?r\gh\t long ages ( associations & uses mank9d has be/[$ ^u x _m attributes4 ,9 fact1 x is possible t light1 color1 & d>kness possess c]ta9 fundam5tally innate p[]s2 at lea/1 !y h acquir$ expressive & impressive p[]s ?r\gh ! _m associations 9 my?ology1 religion1 nature1 & common usage4 ,besides ^! attributes1 light possesses a great advantage ov] ! m$ia ( decoration 9 obta9+ brightness & color effects4 ,= example1 ! l&scape arti/ _c reproduce ! range ( values or brightnesses 9 mo/ ( nature's sc5es1 = if black is us$ to repres5t a deep %ad[1 :ite is n bright en\gh to repres5t ! value ( ! sky4 ,9 fact1 ! range ( brightnesses repres5t$ by ! deep %ad[ & ! sky ext5ds f> beyond ! range repres5t$ by black & :ite pigm5ts4 ,! extreme contra/ ord9>ily available by means ( arti/'s colors is ab\t ?irty to "o1 b ! sky is a ?\s& times bright] ?an a %ad[1 a sunlit cl\d is ?\s&s ( times bright] ?an ! deep %ad[s ( woods1 & ! sun is millions ( times bright] ?an ! %ad[s 9 a l&scape4 ,! range ( brightnesses obta9able by means ( light ext5ds f d>kness or black ?r\gh\t ! range repres5t$ by pigm5ts "u equal illum9ation & beyond ^! ?r\gh ! enorm\s range obta9able by unequal illum9ation ( surfaces to ! brightnesses ( ! light-s\rces !mselves4 ,9 ! matt] ( purity ( colors1 light surpasses reflect+ m$ia1 = x is easy to obta9 approximately pure hues by means ( light & to obta9 pure spectral hues by resort+ to ! spectrum ( light4 ,x is impossible to obta9 pure hues by means ( pigm5ts or ( o!r reflect+ m$ia4 ,^! advantages ( light are v evid5t on turn+ to spectacul> light+ effects1 & ev5 ! light+ ( int]iors illu/rates a pot5tiality 9 light sup]ior to o!r m$ia4 ,= example1 9 a mod]n int]ior 9 :i* conceal$ light+ produces brilliantly illum9at$ areas above a cornice & d>k %ad[s on ! "u side1 ! range 9 values is (t5 mu* great] ?an t repres5t$ by black & :ite1 & /ill !re rema9s ! possibility ( employ+ ! light-s\rces !mselves 9 ext5d+ ! scale ( brightness4 ,sup]pos+ color ^u ! :ole x is obvi\s t ! comb9ation ( prim>y light ) reflect$ light possesses mu* great] pot5tiality ?an ! latt] alone4 ,?is pot5tiality ( light is be/ realiz$ if light+ is reg>d$ z pa9t+ ) light 9 a mann] analog\s to ! decorator's pa9t+ ) pigm5ts1 etc4 ,! expressive possibilities ( light+ f9d ext5sive applications 9 relation to pa9t+1 sculpture1 & ar*itecture4 ,a pa9t+ is an expression ( light & ! sculptor's product f9ally dep5ds ^u light+ = its effectiv5ess4 ,light+ is ! ma/] pa9t] & sculptor4 ,x may affect ! values ( a pa9t+ to "s ext5t & x is a great influ5ce ^u ! colors4 ,x molds ! model f :i* ! sculptor works & x molds ! complet$ "w4 ,! direction1 di/ribution1 & quality ( light influ5ce ! appe>ance ( all objects & gr\ps ( !m4 ,aside f ! model+ ( ornam5t1 ! light & %ade effects ( relatively l>ge areas 9 an int]ior su* z walls & ceil+1 ! contra/s 9 ! brightnesses ( alcoves ) t ( ! ma9 int]ior1 & ! %ad[s "u cornices1 beams1 & ar*es are expressions ( light4 ,! decorator is able to produce a c]ta9 mood 9 a giv5 int]ior by v>y+ ! di/ribution ( values & ! *oice ( colors & ! light+ arti/ is able to d likewise1 b ! latt] is ev5 able to alt] ! mood produc$ by ! decorator4 ,= example1 a l>ge int]ior flood$ ) light f conceal$ s\rces has ! air9ess & ext5siv5ess ( outdoors4 ,if light$ solely by means ( s\rces conceal$ 9 an upp] cornice1 ! ceil+ may be bright & ! walls may be relatively d>k by contra/4 ,su* a light+ effect may produce a feel+ ( be+ hemm$ 9 by ! walls )\t a ro(4 ,if ! room is light$ by means ( *&eli]s hung l[ & equipp$ ) %ades 9 su* a mann] t ! l[] portions ( ! walls may be light :ile ! upp] portions ( ! int]ior may be ill def9$1 ! feel+ produc$ may be t ( be+ hemm$ 9 by cr[d+ d>kness4 ,?us light+ is productive ( moods & illusions rang+ f ! my/]y ( cr[d+ d>kness to ! ext5siv5ess ( outdoors4 ,future light+ ( int]iors d\btless w provide an adequacy ( light+ effects :i* w meet ! respective requirem5ts ( v>i\s occasions4 ,a decorative s*eme 9 :i* light & m$ium grays are employ$ produces an int]ior :i* is v s5sitive to light+ effects4 ,to ^! light-&-%ade effects color$ light may add its *>m+ effectiv5ess4 ,n only are color$ light+ effects able to add mu* to ! beauty ( ! sett+ b !y possess c]ta9 o!r p[]s4 ,blue t9ts produce a cold effect & ! yell[ & orange t9ts a w>m effect4 ,= example1 a room w appe> cool] 9 ! summ] :5 illum9at$ by means ( blui% light & a practical application ( ?is effect is 9 ! !at] :i* mu/ attract audi5ces 9 ! summ]4 ,h[ t9t$ illum9ants fit ! _s ( an occasion or ! mood ( a room may be fully appreciat$ only ?r\gh exp]im5ts1 b ^! are s effective t ! future ( light+ w witness ! application ( ! idea ( pa9t+ ) light to its fulle/ ext5t4 ,color is dem&$ 9 o!r fields1 &1 consid]+ its effectiv5ess & sup]iority 9 light+1 x w c]ta9ly be dem&$ 9 light+ :5 its pot5tiality becomes appreciat$ & readily utiliz$4 ,! expressiv5ess ( light is always evid5t 9 a l&scape4 ,on a sunny day ! mood ( a sc5e v>ies ?r\gh\t ! day & x gr[s m entic+ & agreeable z ! %ad[s l5g!n t[>d ev5+4 ,! arti/ 9 pa9t+ a des]t sc5e employs %ort h>% %ad[s if he desires to sugge/ ! excessive heat4 ,^! %ad[s sugge/ ! rel5tless noonday sun4 ,! ov]ca/ sky is univ]sally depress+ & x has be5 f\nd t on a sunny day mo/ p]sons exp]i5ce a slight depression :5 a cl\d obscures ! sun4 ,nature's light+ v>ies f mom5t to mom5t1 f day to day1 & f season to season4 ,x pres5ts ! extremes ( v>iation 9 di/ributions ( light f ov]ca/ to sunny days & 9 ! latt] cases ! %ad[s are cont9ually %ift+ ) ! sun's altitude4 ,!y are h>%e/ at noon & gradually fade z !y l5g!n1 until at sunset !y disappe>4 ,! colors ( sunlit surfaces & ( %ad[s v>y f sunrise to sunset4 ,^! are ! fundam5tal v>iations 9 ! light+1 b 9 ! v>i\s sc5es ! light+ effects are fur!r modifi$ by cl\ds & by local conditions or environm5t4 ,! va/ outdoors provides a fruitful field = ! /udy ( ! expressiv5ess ( light4 ,hav+ become conv9c$ ( ?is p[] ( light1 ! light+ exp]t may turn to artificial light1 :i* is s easily controll$ 9 direction1 di/ribution1 & color1 & draw ^u its pot5tiality4 ,n only is x easy to provide a light+ suitable to ! mood or to ! function ( an int]ior b x is possible to obta9 "s v>iety 9 effect s t ! light+ may always suit ! occasion4 ,a /udy ( nature's light+ reveals "o great pr9ciple1 namely1 v>iety4 ,mank9d dem&s v>iety 9 mo/ ( 8 activities4 ,"w is v>i$ & alt]nat$ ) recreation4 ,meals are n always ! same4 ,clo?+1 decorations1 & furni%+s are reliev$ ( monotony4 ,"o ( ! mo/ pot5t features ( artificial light is ! ease ) :i* v>iety may be obta9$4 ,9 obta9+ relief f ! monotony ( decorations & furni%+s1 consid]able exp5se & inconv5i5ce are inevitably enc\nt]$4 ,) an adequate supply ( outlets1 circuits1 & controls a wide v>iety ( light+ effects may be obta9$ ) p]haps an insignificant increase 9 ! initial inve/m5t4 ,v>iety is ! spice ( light+ z well z ( life4 ,^! v>i\s pr9ciples ( light+ are readily exemplifi$ 9 ! light+ ( ! home1 :i* is discuss$ 9 ano!r *apt]4 ,! *ur* is ev5 a bett] example ( ! expressive possibilities ( light+4 ,! ar*itectural features are g5]ally ( a c]ta9 p]iod & fir/ ( all x is ess5tial to h>monize ! light+ effect ) t ( ! ar*itectural & decorative s*eme4 ,obvi\sly1 ! d>k-/a9$ ceil+ ( a c]ta9 type ( *ur* w\ld n be flood$ ) light4 ,! fact t x is made d>k by /a9+ precludes su* a proc$ure 9 light+4 ,! *>act]i/ics ( cre$s are di/9ctly diff]5t & ^! are to "s ext5t exemplifi$ by ! l9es ( ! ar*itecture ( _! *ur*es4 ,9 ! same way ! light+ effect may be h>moniz$ ) ! cre$ & ! _s ( ! int]ior4 ,! light+ may always be dignifi$1 impressive1 & congru\s4 ,few *ur*es are prop]ly light$ ) a high int5sity ( illum9ation2 mod]ate light+ is m appropriate1 = x is conducive to ! _s ( wor%ip4 ,9 "s cre$s a dom9ant note is extreme p5it5ce & sev]ity4 ,! ar*itecture may possess h>% outl9es1 & ?is sev]ity or extreme solemnity may be express$ 9 light+ by h>%] contra/s1 al?\gh ?is does n mean t ! light+ mu/ be gl>+4 ,on ! o!r h&1 9 a c]ta9 mod]n cre$ ! dom9ant note appe>s to be *e]fulness4 ,! spaci\s int]iors ( ! *ur*es ( ?is cre$ are lack+ 9 sev]e l9es & ! walls & ceil+s are highly reflect+4 ,adequate illum9ation by means ( diffus$ light )\t ! production ( sev]e contra/s expresses ! cre$1 mod]nity1 & enlight5m5t4 ,on ! alt> ( c]ta9 *ur*es ! expressiv5ess ( light is utiliz$ 9 ! c]emonial uses :i* v>y ) ! cre$4 ,ev5 ! symbolism ( color may be appropriately wov5 into ! light+ ( ! *ur*4 ,! expressiv5ess ( light & color orig9at$ ?r\gh ! contact ( primitive man ) nature4 ,sunlight meant w>m? & a b\ntiful vegetation1 b d>kness re/rict$ 8 activities & h>bor$ manifold dang]s4 ,_m associations ?us orig9at$ & !y 7 ext5d$ ?r\gh ignorance & sup]/ition4 ,yell[ is naturally emblematical ( ! sun & x became ! symbol ( w>m?4 ,br[n z ! pr$om9ant color ( ! autumn foliage became t9ctur$ ) sadness because ! decay ( ! vegetation presag$ ! dea? ( ! ye> & ! cold dre>y mon?s ( w9t]4 ,! fir/ signs ( gre5 vegetation 9 ! spr+ 7 welcom$ z an end ( w9t] & a beg9n+ ( ano!r b\ntiful summ]2 h5ce gre5 symboliz$ y\? & hope4 ,x became associat$ ) ! spr+time ( life & ?us signifi$ inexp]i5ce1 b z ! color ( vegetation x also meant life itself & became a symbol ( immortality4 ,blue acquir$ c]ta9 div9e attributes because1 z ! color ( ! sky1 x 0 associat$ ) ! abode ( ! gods or heav54 ,also a blue sky is ! acme ( s]5ity & ?is color acquir$ c]ta9 appropriate attributes4 ,associations ( ?is "* became wov5 into my?ology & ?us became firmly e/abli%$4 ,poets h felt ^! influ5ces ( light & color 9 nature & h giv5 expression to !m 9 words4 ,!y also h entw9$ mu* ( ! my?ology ( pa/ civilizations & ^! repetitions h help$ to e/abli% ! expressiv5ess ( light & color4 ,e>ly ecclesia/s employ$ ^! symbolisms 9 religi\s c]emonies & dictat$ ! g>bs ( sa9ts & o!r religi\s p]sonages 9 ! pa9t+s :i* decorat$ _! edifices4 ,?us !re 7 _m influ5ces at "w dur+ ! e>ly c5turies :5 intellects 7 p>ticul>ly susceptible ?r\gh sup]/ition & lack ( k4 ,! result has be5 an ext5sive symbolism ( light1 color1 & d>kness4 ,at ! pres5t "t x is difficult to sep>ate ! innate appeal ( light1 color1 & d>kness f ^? attributes :i* h be5 acquir$ ?r\gh associations4 ,possibly light & color h no innate p[]s b m]ely appe> to h because ! acquir$ attributes h be5 s ?or\ghly e/abli%$ ?r\gh usage & common cons5t4 ,space does n p]mit a discussion ( ?is po9t1 b ! *ief aim is consummat$ if ! exi/5ce ( an expressiv5ess & impressiv5ess ( light is e/abli%$4 ,!re are _m o!r symbolisms ( color & light :i* h aris5 9 v>i\s ways b x is f> beyond ! scope ( ?is book to discuss !m4 ,psy*ological inve/igations reveal _m int]e/+ facts p]ta9+ to ! influ5ce ( light & color ^u mank9d4 ,:5 *oos+ color = color's sake alone1 t is1 divorc$ f any associations ( usage1 mank9d pref]s ! pure colors to ! t9ts & %ades4 ,x is int]e/+ to note t ?is is 9 accord ) ! pref]5ce exhibit$ by unciviliz$ be+s 9 _! use ( colors = decorat+ !mselves & _! surr\nd+s4 ,civiliz$ mank9d *ooses t9ts & %ades pr$om9antly to live )1 t is1 = ! decoration ( 8 surr\nd+s4 ,h[ev]1 civiliz$ man & ! savage appe> to h ! same fundam5tal pref]5ce = pure colors & app>5tly culture & ref9em5t are responsible = _! diff]5ce 9 *oice ( colors to live )4 ,?is is an int]e/+ discov]y & x has its applications 9 light+1 especially 9 spectacul> & /age-light+4 ,x appe>s to be fur!r e/abli%$ t :5 civiliz$ man *ooses color = color's sake alone he n only pref]s ! pure colors b among ^! he pref]s ^? ne> ! ends ( ! spectrum1 su* z r$ & blue4 ,r$ is favor$ by wom51 ) blue a close second1 b ! rev]se is true = m54 ,x is also ?or\ghly e/abli%$ t r$1 orange1 & yell[ ex]t an excit+ influ5ce2 yell[-gre51 gre51 & blue-gre51 a tranquiliz+ influ5ce1 & blue & violet a subdu+ influ5ce ^u mank9d4 ,all ^! results 7 obta9$ ) colors divorc$ f surr\nd+s & actual usage4 ,9 ! use ( light & color ! laws ( h>mony & e/hetics mu/ be obey$1 b ! s5sibility ( ! light+ arti/ is a satisfactory guide4 ,h>monies are ( _m v>ieties1 b !y may be g5]ally gr\p$ into two classes1 ^? ( analogy & ^? ( contra/4 ,! =m] includes colors closely associat$ 9 hue & ! latt] includes complem5t>y colors4 ,no rules 9 simplifi$ =m c be pres5t$ = ! production ( h>monies 9 light & color4 ,^! simplifications are made only by ^? :o h n look$ deeply en\gh into ! subject ?r\gh obs]vation & exp]im5t to see its complexity4 ,! expressiv5ess ( light f9ds applications ?r\gh\t ! va/ field ( light+1 b ! /age (f]s great opportunities :i* h be5 b>ely drawn ^u4 ,:5 "o has awak5$ to ! va/ possibilities ( light1 %ade1 & color z a means ( expression x is difficult to suppress a critical attitude t[>d ! crudity ( light+ effects on ! pres5t /age1 ! lack ( k p]ta9+ to ! lat5t possibilities ( light1 & ! sup]ficial use ( ?is pot5tial m$ium4 ,! crude realism & ! almo/ total abs5ce ( deep insight into ! attributes ( light & color are ! *ief defects ( /age-light+ to-day4 ,"o turns hopefully t[>d ! gallant ?\gh small b& ( /age arti/s :o are /riv+ to realize a h>mony ( light+1 sett+1 & drama 9 ! s-call$ mod]n !at]4 ,unappreciat$ by a public :i* flocks to ! melodramatic movie1 ^: sc5>ios produc$ ^u ! legitimate /age w\ld be je]$ by ! same public1 ! mod]n /age arti/ is /riv+ to utilize ! pot5tiality ( light4 ,b ev5 among ^! !re are impo/ors :o h nev] a*iev$ any?+ wor? :ile & h n ! p]sev]ance to le>n to extract "s ( ! p[] ( light & to apply x effectively4 ,light+ suff]s 9 ! h&s ( ! arti/ ow+ to ! abs5ce ( sci5tific k & x is misus$ by ! eng9e] :o does n possess an e/hetic s5sibility4 ,sci5ce & art mu/ be l9k$ 9 light+4 ,! wor?y ef=ts ( /age arti/s 9 "s ( ! mod]n !at]s lack ! support ( ! produc]s1 :o cat] to ! ta/e ( ! public :i* pays ! admission fees4 ,app>5tly ! mod]n !at] mu/ fir/ pass ?r\gh a p]iod 9 :i* f9ancial support mu/ be obta9$ f ^? :o are able to give x1 j z ! symphony or*e/ra has be5 support$ = ! sake ( art4 ,c]ta9ly ! "t is at h& = philan?ropy to come to ! aid ( wor?y & capable /age arti/s :o hope to rescue !atrical production f ! mire ( comm]cialism4 ,^? :o h n view$ /age-light+ f beh9d ! sc5es w\ld (t5 be surpris$ at ! crudity ( ! equipm5t1 & especially at ! sup]ficial intellects :i* are responsible = "s ( ! reali/ic effects obta9$4 ,b ^! are ! result usually ( exp]im5t1 n ( direct$ k4 ,fur!rmore1 little ?\ght is giv5 to ! emotional value ( light1 %ade1 & color4 ,! flood ( light & ! spot ( light are v>i$ ) gaudy color-effects1 b h[ seldom is x possible to di/+ui% a deep relation betwe5 ! light+ & ! dramatic incid5ts6 ,illu/ration3 ,soldi]s' & ,sailors' ,monum5t ,jewel$ portal welcom+ return$ soldi]s ,,artificial ,,light ,,honor+ ,,^? ,,:o ,,fell ,,& ,,^? ,,:o ,,return$ ,illu/ration ,illu/ration3 ,,! ,,expressiv5ess ,,( ,,light ,,9 ,,*ur*es ,9 mu* ( ! =ego+ discussion ! pres5t pr$om9at+ !atrical productions are n consid]$1 = ! light+ effects are good en\gh = !m4 ,_m +5i\s tricks & devices are resort$ to 9 ^! productions1 & z a :ole light+ is s]v+ effectively en\gh4 ,b 9 consid]+ ! expressiv5ess ( light ! deep] play is ! m$ium necess>y = utiliz+ ! pot5tiality ( light4 ,^! are r>e & un=tunately ! /age arti/ appreciative ( ! significations & emotional value ( light & color is /ill r>]4 ,! equipm5t ( ! pres5t /age consi/s ( footlights1 side-lights1 bord]-lights1 flood-lights1 spot-lights1 & mu* special app>atus4 ,"o ( ! sev]e/ criticisms ( /age-light+ f an arti/ic po9t ( view may be direct$ aga9/ ! use ( footlights = obta9+ ! dom9ant light4 ,?is is direct$ upw>d & ! effect is an unnatural & ev5 a grotesque model+ ( ! actors' features4 ,! %ad[s produc$ are incongru\s1 = !y are oppos$ to ! o!r real & pa9t$ effects ( light & %ade4 ,! only excuse = su* light+ is t x is easily done & t prop] light+ is difficult to obta91 ow+ to ! fact t x involves a *ange 9 con/ruction4 ,by no means %\ld ! footlights be ab&on$1 = !y w\ld /ill be invaluable 9 obta9+ diffus$ light ev5 :5 ! dom9ant light is direct$ f above ! horizontal4 ,9 ! pres5t /age-light+1 9 :i* ! footlights g5]ally pr$om9ate1 ! expressiv5ess ( light is n satisfactory4 ,p]haps !y are a necess>y compromise1 b inasmu* z _! effect is unnatural !y %\ld n be accept$ until x is ?or\ghly prov$ t +5uity _c elim9ate ! pres5t defects4 ,! /age z a :ole is a mobile picture 9 light1 %ade1 & color ) ! addition ( words & music4 ,except+ ! latt]1 x is an expression ( light wor?y ( ! same c>e & consid]ation t ! pa9t+1 :i* is also an expression ( light1 receives f ! arti/4 ,! sc5]y & co/umes %\ld be consid]$ 9 t]ms ( ! light+ effects because !y are affect$ by *anges 9 ! color ( ! light4 ,9 fact1 ! au?or %[$ a numb] ( ye>s ago t by c>efully relat+ ! colors ( ! light ) ! colors us$ 9 pa9t+ ! sc5]y1 a complete *ange ( sc5e c be obta9$ by m]ely *ang+ ! color ( ! light4 ,r wond]ful dissolv+ effects c be produc$ 9 ?is mann] )\t %ift+ sc5]y4 ,= example1 a w>m summ] sc5e ) trees 9 full foliage "u a yell[ light may be *ang$ "u a blui% light to a w9t] sc5e ) gr\nd cov]$ ) sn[ & trees b>r5 ( leaves4 ,b be=e su* accompli%m5ts c be realiz$ ^u ! /age1 sci5tific k mu/ be available beh9d ! sc5es4 ,! art museum af=ds a multitude ( opportunities = utiliz+ ! expressiv5ess ( light4 ,?is is m g5]ally true ( sculptur$ objects ?an ( pa9t+s because ! latt] may be treat$ z a :ole4 ,! arti/ almo/ inv>iably pa9ts a picture by daylight & unless x is illum9at$ by daylight x is alt]$ 9 appe>ance1 t is1 x becomes ano!r picture4 ,! great diff]5ce 9 ! appe>ance ( a pa9t+ "u daylight & ord9>y artificial light is q />tl+1 :5 demon/rat$ by means ( app>atus 9 :i* ! two effects may be rapidly alt]nat$4 ,art museums are suppos$ to exhibit ! works ( arti/s &1 !re=e1 no *anges 9 ^! works %\ld be tol]at$ if !y c be avoid$4 ,! mod]n artificial-daylight lamps make x possible to illum9ate gall]ies ) light at night :i* approximates daylight4 ,a fur!r advantage ( artificial light is t x may be easily controll$ & a m satisfactory light+ may be obta9$ ?an ) natural light4 ,consid]+ ! co/ ( daylight 9 museums & its disadvantages x appe>s possible t artificial daylight ) its advantages may replace x ev5tually 9 ! l>ge gall]ies4 ,if ! works ( arti/s are really priz$ = _! appe>ance1 ! light+ ( !m is v important4 ,sculpture is model$ by light & al?\gh x is impossible to asc]ta9 ! light+ "u :i* ! sculptor view$ 8 complet$ "w ) pride & satisfaction1 x is possible to give ! be/ consid]ation to its light+ 9 its f9al place ( exhibition4 ,! appe>ance ( a sculpture dep5ds ^u ! dom9ant direction ( ! light1 ! solid-angle subt5d$ by ! light-s\rce 7skylight1 area ( sky1 etc47 & ! am\nt ( scatt]$ light4 ,! direction ( dom9ant light det]m9es ! g5]al direction ( ! %ad[s2 ! solid-angle ( ! light-s\rce affects ! "* ( ! edges ( ! %ad[s2 & ! scatt]$ light acc\nts = ! brightness ( ! %ad[s4 ,x %\ld be obvi\s t v>iations ( ^! factors affect ! appe>ance or expression ( ?ree-dim5sional objects4 ,!re=e ! position ( a sculptur$ object ) respect to ! w9d[ or o!r skylight & ! am\nt ( light reflect$ f ! surr\nd+s are important4 ,visits to art museums ) ^! factors 9 m9d reveal a gross neglect 9 ! light+ ( objects ( art :i* are suppos$ to appeal by virtue ( _! appe>ances1 = !y c ar\se ! emotions only ?r\gh ! doorway ( vision4 ,a c5tury ago mank9d gave no ?\ght to utiliz+ ! expressive & impressive p[]s ( light except 9 religi\s c]emonies4 ,x 0 n practicable to utilize light f ! feeble flames ( ^? days 9 ! elaborate mann] necess>y to draw ^u ^! p[]s4 ,man 0 conc]n$ ) ! m press+ ne$s4 ,he want$ en\gh light to make ! w9t] ev5+s endurable & ! /reets reasonably safe4 ,! arti/s ( ^? days saw ! wond]ful expressions ( light exhibit$ by ,nature1 b !y d>$ n dream ( rival+ ^! ) artificial light4 ,to-day ,nature surpasses man 9 ! production ( light+ effects only 9 magnitude4 ,man surpasses h] arti/ically4 ,9 fact1 ! arti/ becomes a ma/] only :5 he c improve ^u h] sett+s2 :5 he is able by r>e judgm5t 9 *oos+ & 9 elim9at+ & by skill & +5uity to sub/itute a complete h>mony = h] incomplete & unsatisfactory reality4 ,b ev]y:]e ,nature is ! great tea*]1 = h] _w is full ( an ev]*ang+ inf9itude ( expressions ( light4 ,mank9d ne$s only to /udy ^! ) an attun$ s5sibility to be able ev5tually to play ! music ( light = ^? :o are bless$ ) an e/hetic s5se4 ,,xxiv ,,light+ ,,! ,,home ,9 ! home artificial light ex]ts its influ5ce ^u e "o4 ,)\t artificial light+ ! family circle may n h become ! important civiliz+ influ5ce t x is to-day4 ,c]ta9ly civiliz$ man n[ %udd]s at ! ?\ght ( sp5d+ 8 ev5+s 9 ! light ( ! fire ^u ! he>? or ( a burn+ spl9t]4 ,! importance ( artificial light is emphatically impress$ ^u ! h\sehold] :5 he is =c$ tempor>ily to dep5d ^u ! primitive c&le ?r\gh ! failure ( ! mod]n sy/em ( light+4 ,he flees f 8 home to t ( 8 m =tunate neighbor1 or he retires 9 8 helplessness to awak5 9 ! morn+ ) a bless+ = daylight4 ,he _c conceive ( happ9ess & recreation 9 ! homes ( a c5tury or two ago1 :5 a few c&les or an oil-lamp or two 7 ! sole s\rces ( light4 ,b :5 ! electric or gas s]vice is aga9 re/or$ he relapses %ortly into 8 =m] placid indiff]5ce t[>d ! wond]fully effici5t & adequate artificial light ( ! pres5t age4 ,until rec5tly artificial light 0 co/ly & ! h\sehold] 9 common ) o!r us]s ( light did n conc]n himself ) ! "q ( adequate & arti/ic light+4 ,8 *ief aim 0 to utilize z little z possible1 = co/ 0 always =emo/ 9 8 m9d4 ,! developm5t ( ! sci5ce ( light-production has be5 s rapid dur+ ! pa/ g5]ation t adequate1 effici5t1 & *eap artificial light f9ds mank9d unconsci\sly view+ light+ ) ! same attitude z he displays t[>d 8 food & fuel bills4 ,ano!r consequ5ce ( ?is rapid developm5t is t mank9d does n "k h[ to extract ! joy f mod]n artificial light4 ,?is is readily demon/rat$ by analyz+ ! light+ ( middle-class homes4 ,! co/ ( light has be5 discuss$ 9 ano!r *apt] & x has be5 %[n t x has decreas$ enorm\sly 9 a c5tury4 ,x is n[ ! mo/ pot5tial ag5cy 9 ! home :5 view$ f ! /&po9t ( co/4 ,! av]age h\sehold] pays less ?an tw5ty doll>s p] ye> = ev]-ready light ?r\gh\t 8 home4 ,= ab\t five c5ts p] day ! av]age family enjoys all ! bless+s ( mod]n light+1 :i* is suffici5t pro( t co/ is an insignificant item4 ,9 ord] to simplify ! discussion ( light+ ! home ! t]m9ology ( electric-light+ w be us$4 ,! pr9ciples exp\nd$ apply z well to gas z to electricity1 & ow+ to ! +5uity ( ! gas-light+ exp]ts1 ! possibilities ( gas-light+ are ext5sive despite its h&icaps4 ,!re are "s places 9 ! home1 su* z ! kit*5 & basem5t1 :]e light+ is purely utilit>ian 9 ! n>r[ s5se1 b 9 mo/ ( ! rooms ! e/hetic or1 m broadly1 ! psy*ological aspects ( light+ %\ld dom9ate4 ,pure utility is always a by-product ( arti/ic light+ & fur!rmore1 ! light+ effects w be )\t gl>e :5 !y satisfy all ! dem&s ( e/hetics4 ,9 deal+ ) light+ 9 ! home ! h\sehold] %\ld conc5trate 8 att5tion ^u light+ effects4 ,un=tunately1 he is n taught to d s1 = ev]y:]e he turns = help he f9ds ! discussion direct$ t[>d fixtures & lamps in/ead ( t[>d light+ effects4 ,h[ev]1 ^! are m]ely l9ks 9 ! *a9 f ! met] to ! eye4 ,lamps are ( int]e/ f ! /&po9t ( quantity & quality ( light1 & fixtures are ( importance *iefly z di/ribut]s ( light4 ,^! details are m]ely means to an end & ! end is ! light+ effect4 ,( c\rse1 ! fixtures are m important z objects ?an ! wires because !y are visible & %\ld h>monize ) ! g5]al decorative & ar*itectural s*eme4 ,! home is ! !at] ( life full ( v>i\s moods & occasions2 h5ce ! light+ ( a home %\ld be flexible4 ,a degree ( v>iety %\ld be possible4 ,controls1 wir+1 outlets1 & fixtures %\ld conspire to provide ?is v>iety4 ,at ! pres5t "t ! av]age h\sehold] does n give mu* att5tion to light+ until he pur*ases fixtures4 ,x is probable t he ?\ght ( x :5 he laid out or approv$ ! wir+1 b usually he does n consid] x s]i\sly until he visits ! fixture-deal] to pur*ase fixtures4 ,& !n un=tunately ! fixture-deal] does n light 8 home2 he does n sell ! h\sehold] light+-effects design$ to meet ! requirem5ts ( ! p>ticul> home2 he sells m]ely fixtures4 ,un=tunately !re are few fixtures available :i* h def9ite aims 9 light+ z dem&$ by ! home4 ,( ! great v>iety ( fixtures available !re are _m arti/ic objects1 b x is obvi\s t little att5tion is giv5 to _! design f ! /&po9t ( light+4 ,t ! fixture-deal] usually ?9ks ( fixtures z objects & gives little or no ?\ght to light+ effects is app>5t f 8 conv]sation & f 8 display4 ,he exhibits fixtures usually en masse & seldom attempts to illu/rate ! light+ effects produc$ 9 ! room4 ,! =ego+ criticisms are pres5t$ to emphasize ! fact t ?r\gh\t ! field ( light+ ! great possibilities :i* h be5 op5$ by mod]n light-s\rces are n fully appreciat$4 ,! po9t at :i* to beg9 to design ! light+ = a home is ! wir+4 ,un=tunately ?is is too (t5 done by a contractor :o has giv5 no special ?\ght to ! possibilities ( light+ & to ! requirem5ts 9 wir+ & swit*es necess>y 9 ord] to realize !m4 ,at ?is po9t ! h\sehold] %\ld attempt to =m an op9ion z to ! relative values4 ,is artificial light+ important en\gh to w>rant an exp5diture ( two p] c5t4 ( ! total inve/m5t 9 ! home & its furni%+s8 ,! answ] w dep5d ^u ! ext5t to :i* artificial light is appreciat$4 ,x appe>s t f\r or five p] c5t4 is n too mu* if x is admitt$ t ! artificial light+ sy/em ranks next to ! heat+ plant 9 importance & t ^! two are ! mo/ important features ( an int]ior ( a resid5ce4 ,a swit* or a basebo>d outlet co/s an insignificant sum b ei!r may pay = itself _m times 9 ! c\rse ( a few ye>s ?r\gh its utility or conv5i5ce4 ,x appe>s be/ to take up ?is subject room by room because ! requirem5ts v>y consid]ably1 b 9 ord] to be specific 9 ! discussions1 a middle-class home w be *os54 ,! m important rooms w be treat$ fir/ & v>i\s simple details w be t\*$ ^u because1 aft] all1 ! prop] light+ ( a home is realiz$ by att5tion to small details4 ,! liv+-room is ! sc5e ( _m functions4 ,x s]ves at times = ! quiet ga!r+ ( ! family1 ea* memb] devot$ to read+4 ,at ano!r "t x may conta9 a happy company engag$ at c>ds or 9 conv]sation4 ,! light+ requirem5ts v>y f a spot or two ( light to a flood ( light4 ,except+ 9 ! small liv+-rooms !re does n appe> to be a s+le good reason = a ceil+ fixture4 ,x is ne>ly always 9 ! field ( vision :5 occupants are engag$ 9 conv]sation1 & = read+ purposes ! portable lamp ( satisfactory design has no rival4 ,wall brackets _c supply g5]al light+ )\t be+ too bright = com=t4 ,if !y are heavily %ad$ !y may /ill emit pl5ty ( light upw>d1 b ! adjac5t spots on ! walls or ceil+ w g5]ally be too bright4 ,wall brackets may be beautiful ornam5ts & decorative spots ( light & h a "r to exi/ z su*1 b !y _c be safely dep5d$ ^u = adequate g5]al light+ on ^? occasions :i* dem& su* light+4 ,z a g5]al pr9ciple1 x is well to visualize ! furniture 9 ! room :5 look+ at ! ar*itect's draw+s & x is advantage\s ev5 to cut out pieces ( pap] repres5t+ ! furniture 9 scale4 ,by plac+ ^! on ! draw+s ! furni%$ room is readily visualiz$ & ! locations ( basebo>d outlets become evid5t4 ,x appe>s t ! be/ me?od ( light+ a liv+-room is by means ( decorative portable lamps4 ,su* lamps are really light+-furniture1 = !y aid 9 decorat+ & 9 furni%+ ! room at all times4 ,a numb] ( ^! lamps 9 ! liv+-room insures great flexibility 9 ! light+1 & ! light may be kept localiz$ if desir$ s t ! room is re/ful4 ,a room ^: ceil+ & walls are brilliantly illum9at$ is n s com=table = long p]iods z "o 9 :i* ^! areas are dimly light$4 ,fur!rmore1 ! latt] is m conducive to read+ & to o!r ef=ts at conc5tration4 ,! furniture may be readily %ift$ z desir$ & ! portable lamps may be re>rang$4 ,su* light+ s]ves all ! purposes ( ! liv+-room except+ ^? requir+ a flood ( light1 b x is easy to conceal elaborate light+ me*anisms und]nea? ! %ades ( portable lamps4 ,sev]al types ( portable lamps are available :i* supply an indirect compon5t z well z direct light4 ,! =m] illum9ates ! ceil+ ) a flood ( light )\t any discom=t+ gl>e4 ,su* a light+-unit is "o ( ! mo/ satisfactory = ! home1 = two di/9ct effects & a comb9ation ( ^! introduce a desirable elem5t ( v>iety into ! light+4 ,n less ?an f\r & pref]ably six basebo>d outlets %\ld be provid$ 9 a liv+-room ( mod]ate size4 ,"o outlet on ! mantel is also to be desir$ = connect+ decorative c&le/icks1 & brackets above ! fireplace are ( ornam5tal value4 ,al?\gh ! abs5ce ( ceil+ fixtures improves ! appe>ance ( ! room1 wir+ may be provid$ = ceil+ outlets 9 new h\ses z a matt] ( insurance aga9/ ! possible ne$s ( ! future4 ,:5 ceil+ fixtures are n us$1 swit*es may be provid$ = ! mantel brackets or c]ta9 basebo>d outlets 9 ord] t light may be _h ^u ent]+ ! room4 ,! m]its ( a portable lamp may be asc]ta9$ be=e pur*as+ by actual demon/ration4 ,"s ( !m are n satisfactory = read+-lamps1 ow+ to ! %ape ( ! %ade or to ! position ( ! lamps4 ,! utility ( a table lamp may be det]m9$ by plac+ x ^u a table & not+ ! spread ( light :ile seat$ 9 a *air beside x4 ,a floor lamp may also be te/$ v easily4 ,a m9iature floor lamp ab\t f\r feet 9 height ) an appropriate %ade provides an excell5t lamp = read+ purposes because x may be plac$ by ! side ( a *air or mov$ ab\t indep5d5t ( o!r furniture4 ,a tall floor lamp (t5 s]ves = light+ ! piano1 b small piano lamps may be f\nd :i* are decorative z well z s]viceable 9 illum9at+ ! music )\t gl>e4 ,! d9+-room pres5ts an entirely diff]5t problem = ! sett+ is v def9ite4 ,! d9+-table is ! mo/ important area 9 ! room & x %\ld be ! mo/ brilliantly illum9at$ area 9 ! room4 ,a demon/ration ( ?is po9t is ?or\ghly conv9c+4 ,! decorator :o designs wall brackets = ! d9+-room is int]e/$ 9 beautiful objects ( art & n 9 a prop] light+ effect4 ,! fixture-deal]1 hav+ fixtures to sell & n recogniz+ t he c\ld fill a cry+ ne$ z a light+ speciali/1 is z likely to sell a semi-indirect or an indirect light+ fixture z he is to provide a prop]ly balanc$ light+ effect ) ! table brightly illum9at$4 ,! indirect & semi-indirect units illum9ate ! ceil+ pr$om9antly ) ! result t ?is bright area di/racts att5tion f ! table4 ,a brightly illum9at$ table holds ! att5tion ( ! d9]s4 ,light attracts & a semi-d>kness ov] ! rema9d] ( ! room cr[ds 9 ) a result t is f> m satisfactory ?an t ( a d9+-room flood$ ) light4 ,! old-fa%ion$ dome :i* hung ov] ! d9+-table has s]v$ well1 = x illum9at$ ! table & left ! rema9d] ( ! room dimly light$4 ,b its wide ap]ture made x necess>y to susp5d x r l[ 9 ord] t ! lamps )9 %\ld n be visible4 ,x is an obtrusive fixture & despite its excell5t light+ effect1 x w5t out ( /yle4 ,b satisfactory light+ pr9ciples nev] become antiquat$1 & z ta/e 9 fixtures *anges ! pr9ciples may be reta9$ 9 new fixtures4 ,mod]n domes are available :i* are excell5t = ! d9+-room if ! lamps are well conceal$4 ,! s-call$ %[]s are satisfactory if ! %ades are d5se & ( su* %ape z to conceal ! lamps f ! eyes4 ,v>i\s modifications readily sugge/ !mselves to ! al]t fixture-design]4 ,ev5 ! h\sewife c d mu* ) silk %ades :5 ! pr9ciple ( light+ ! d9+-table is und]/ood4 ,! s-call$ c&elabra h be5 sold ext5sively = d9+-rooms & !y are fairly satisfactory if equipp$ ) %ades :i* reflect mu* ( ! light d[nw>d4 ,semi-indirect & indirect fixtures h _m applications 9 light+1 b !y d n provide ! prop] effect = a d9+-room4 ,x is easy to make a special fixture :i* w s5d a compon5t ( light d[nw>d to ! table & w p]mit a small am\nt ( diffus$ light to ! ceil+ & walls4 ,if a daylight lamp is us$ = ! direct compon5t1 ! table w appe> v beautiful4 ,"u ?is light ! l95 & *9a are :ite1 fl[]s & decorations on ! *9a appe> 9 _! full colors1 ! silv] is attractive1 & ! v>i\s color-h>monies su* z butt]1 paprika1 & bak$ potato are entic+4 ,?is is an excell5t place = a daylight lamp if diffus$ light illum9at+ ! rema9d] ( ! room & ! faces ( ! d9]s is ( a w>m tone obta9$ by w>m yell[ lamps or by filt]+ ^! compon5ts ( ! light ?r\gh orange %ades4 ,! ceil+ fixture %\ld be provid$ ) two circuits & swit*es4 ,9 "s cases x is easy to provide a dangl+ plug = connect+ su* electric equipm5t z a toa/]1 p]colator1 or c&le/icks4 ,two c&le/icks are effective on ! buffet1 b usually ! smalle/ normal-voltage lamps available give too mu* light4 ,m9iature lamps may be us$ ) a small trans=m]1 or two regul> lamps may be connect$ 9 s]ies4 ,at lea/ two basebo>d outlets are conv5i5t4 ,! =ego+ deals ) ! m or less ess5tial light+ ( a d9+-room1 b !re are v>i\s practicable additional light+ effects :i* add mu* *>m to c]ta9 occasions4 ,color$ light ( l[ int5sity obta9$ f a cove or f fl[]-boxes fa/5$ ^u ! wall is v pleas+4 ,if a cove is provid$ ar\nd ! room1 two circuits conta9+ orange & blue lamps respectively w supply two colors widely diff]+ 9 effect4 ,by mix+ ! two a beautiful rose t9t may be obta9$4 ,?is equipm5t has be5 in/all$ ) mu* satisfaction4 ,a simpl] me?od ( obta9+ a simil> effect is to use imitation fl[]-boxes plugg$ into wall outlets4 ,artificial foliage adds to ! *>m ( ^! boxes4 ,! color$ light is m]ely to add ano!r effect on special occasions & its int5sity %\ld nev] be high4 ,9 ! d9+-room su* unusual effects are n out ( place & !y ne$ n be g>i%4 ,! sun-room p>takes ( ! *>act]i/ics ( ! liv+-room to "s ext5t1 b1 x be+ small]1 a semi-indirect fixture may be satisfactory = g5]al illum9ation4 ,h[ev]1 a portable lamp :i* supplies an indirect compon5t ( light besides ! direct light s]ves admirably = read+ z well z = flood+ ! room ) light :5 necess>y4 ,two or ?ree basebo>d outlets are desirable = atta*+ decorative or ev5 purely utilit>ian lamps4 ,! sun-room is an excell5t place = utiliz+ fl[]-box fixtures decorat$ ) artificial foliage4 ,9 fact1 a c5tral fixture may assume ! appe>ance ( a hang+ basket ( foliage4 ,! libr>y & d5 (f] no problems diff]+ f ^? already discuss$ 9 ! liv+-room4 ,a c>eful consid]ation ( ! disposition ( ! furniture w reveal ! be/ positions = ! outlets4 ,9 a small libr>y wall brackets may s]ve z decorative spots ( light & if ! %ades are p5d5t !y may s]ve z lamps = read+ purposes4 ,9 bo? ^! rooms an excell5t read+-lamp is desir$1 b x may be decorative z well4 ,wall outlets may be desir$ = decorative portable lamps ^u ! bookcases4 ,! sleep+-room1 :i* commonly is also a dress+-room1 (t5 exhibits ! errors ( a lack ( =esight 9 light+4 ,9 mo/ rooms ( ?is "* !re is "o be/ arrangem5t ( furniture & if ?is is det]m9$ x is easy to asc]ta9 :]e ! w9d[s & outlets %\ld be locat$4 ,! w9d[s may usually be arrang$ = tw9 b$s z well z = a s+le "o ) obvi\s advantages ( flexibility 9 arrangem5t4 ,) ! position ( ! bureau det]m9$ x is easy to locate outlets = two wall brackets1 "o on ea* side1 ab\t sixty-six in*es above ! floor & ab\t five feet ap>t4 ,:5 ! brackets are equipp$ ) d5se upright %ades1 ! figure be=e ! mirror is well illum9at$ )\t gl>e & suffici5t light rea*es ! ceil+ to illum9ate ! :ole room4 ,a basebo>d outlet %\ld be available = small portable lamps :i* may be us$ ^u ! bureau or = electric heat+ devices4 ,! same is true = ! dress+-table2 inde$1 two small decorative lamps on ! table s]ve bett] ?an high wall brackets ow+ to ! fact t ! us] is seat$4 ,a basebo>d outlet ne> ! head ( ! b$ or betwe5 ! b$s is conv5i5t = a read+-lamp & = o!r purposes4 ,an outlet 9 ! c5t] ( ! ceil+ controll$ by a conv5i5t swit* may be in/all$ on build+1 z insurance aga9/ future ne$s or desires4 ,b a s+le light+-unit 9 ! c5t] ( ! ceil+ does n s]ve adequately ! ne$s at ! bureau & dress+-table4 ,9 fact1 two wall brackets prop]ly locat$ ) respect to ! bureau af=d a light+ mu* sup]ior = all purposes 9 ! b$room to t produc$ by a ceil+ fixture4 ,9 ! ba?-room ! pr9cipal problem is to illum9ate ! p]son1 especially ! face1 be=e ! mirror4 ,_m mi/akes are made at ?is po9t1 despite ! simplicity ( ! solution4 ,9 ord] to see ! image ( an object 9 a mirror1 ! object mu/ be illum9at$4 ,x is be/ to d ?is 9 a /raight=w>d mann] by means ( a small light+-unit on ea* side ( ! mirror at a height ( five feet4 ,bo? sides ( ! face w be well illum9at$ & ! light-s\rces are l[ en\gh to elim9ate objectionable %ad[s4 ,! units may be m]ely pull-*a9 sockets conta9+ fro/$ or opal lamps4 ,a c5t] bracket or a s+le unit susp5d$ f ! ceil+ is n z satisfactory z ! two brackets4 ,^! af=d en\gh light = ! entire ba?-room4 ,a basebo>d or wall outlet is conv5i5t = connect+ a heat]1 curl+-iron1 & o!r electrically heat$ devices4 ,! sew+-room1 :i* 9 ! middle-class home is usually a small room1 is sometimes us$ z a b$room4 ,a ceil+ fixture w supply adequate g5]al light+1 b a basebo>d outlet %\ld be available = a %ort floor lamp or a table lamp = sew+ purposes4 ,an int5se local light is necess>y = ?is occupation1 :i* sev]ely taxes ! eyes4 ,a s-call$ daylight lamp s]ves v well 9 ?is case4 ,illu/ration3 ,,obta9+ ,,two ,,diff]5t ,,moods ,,9 ,a ,,room ,,by ,a ,,portable ,,lamp ,,:i* ,,supplies ,,direct ,,& ,,indirect ,,compon5ts ,,( ,,light ,illu/ration3 ,,! ,,lights ,,( ,,new ,,york ,,city ,t[]+ %afts ( light defy ! d>kness & ?\s&s ( light$ w9d[s symbolize man's successful /ruggle aga9/ nature ,9 ! kit*5 ! wall brackets are easily locat$ aft] ! positions ( ! range1 "w-table1 s9k1 etc41 are det]m9$4 ,a bracket = ea* is advisable unless !y are s locat$ t "o w s]ve two purposes4 ,x is cu/om>y to h a comb9ation fixture = gas & electricity4 ,?is is (t5 susp5d$ f ! c5t] ( ! ceil+1 b inasmu* z ! gas-light _c be close to ! ceil+1 ! fixture ext5ds s f> d[nw>d z to become a nuisance4 ,fur!rmore1 a light-s\rce hung l[ f ! c5t] ( ! ceil+ is 9 su* a position t ! work] 9 ! kit*5 usually works 9 8 %ad[4 ,if a ceil+ outlet is us$ x %\ld be an electrical socket at ! ceil+4 ,! comb9ation fixture is be/ plac$ on ! wall z a bracket4 ,! s-call$ daylight lamps are valuable 9 ! kit*54 ,9 ! basem5t a g5]\s supply ( ceil+ outlets adds mu* to ! satisfaction ( a basem5t4 ,"o 9 ea* lock]1 "o be=e ! furnace1 & a l>ge daylight lamp above b to "o side ( ! laundry trays are wor? _m times _! co/4 ,fur!rmore1 a wall socket = ! electric iron & wa%+-ma*9e is a conv5i5ce v mu* appreciat$4 ,9 ! /airways conv5i5t ?ree-way swit*es = ea* ( ! ceil+ fixtures repres5ts ! be/ practice4 ,a basebo>d outlet 9 ! upp] hall af=ds a connection = a decorative lamp & pays = itself _m times z a place to atta* ! vacuum-clean] f :i* all ! rooms on t floor may be s]v$4 ,9 ve/ibules & on por*es ceil+ fixtures controll$ by means ( conv5i5t swit*es are satisfactory4 ,! entrance hall may be made to express hospitality by means ( light+ :i* %\ld be adequate & arti/ic4 ,an adequate supply ( outlets & wall swit*es is n co/ly & !y pay g5]\s divid5ds4 ,) a scanty supply ( ^!1 ! possibilities ( light+ are v mu* curtail$4 ,!re is no?+ intricate ab\t locat+ swit*es & outlets1 s ! h\sehold] may d ?is himself1 or he may view critically ! plans z submitt$4 ,! *ief difficulties are to ?r[ aside 8 indiff]5ce & to readju/ 8 ideas & values4 ,x may be confid5tly /at$ t ! possibilities ( light+ f> outrank mo/ ( ! features :i* contribute to ! co/ ( a h\se & ( its furni%+s4 ,aft] consid]+ ! requirem5ts & decorative s*emes ( ! v>i\s rooms ! h\sehold] %\ld be compet5t to judge ! appropriat5ess ( ! light+ effects obta9$ f fixtures :i* ! deal] displays1 b he %\ld insi/ ^u a demon/ration4 ,if ! deal] is n equipp$ ) a room = ?is purpose1 he %\ld be ask$ to demon/rate 9 ! rooms to be light$4 ,if ! fixture-deal] does n realize t he %\ld be sell+ light+ effects1 ! h\sehold] %\ld make him und]/& t light+ effects are ( prim>y importance & ! fixtures !mselves are ( second>y int]e/ 9 mo/ cases4 ,! unus$ outlets t h be5 in/all$ = possible future ne$s may be seal$ 9 pla/]+ if ! positions are m>k$ s t !y may be f\nd :5 desir$4 ,an advantage ( portable lamps is t !y may be tak5 away on mov+4 ,9 fact1 :5 light+ is ev5tually consid]$ a p[]ful decorative m$ium1 z x %\ld be1 x is probable t fixtures w be p]sonal prop]ty atta*$ to ceil+1 wall1 & floor outlets by means ( plugs4 ,a v>iety ( inc&esc5t lamps are available4 ,= ! home1 opal1 fro/$1 or b[l-fro/$ lamps are usually m satisfactory ?an cle> lamps4 ,b>e filam5ts %\ld n be visible1 = !y n only cause discom=t & eye-/ra9 b !y spoil :at might o!rwise be an arti/ic effect4 ,lamps ) diffus+ bulbs d mu* t[>d elim9at+ h>% %ad[s ca/ by ! edges ( ! %ades1 by ! *a9s ( ! fixtures1 etc4 ,^! lamps are available 9 _m %apes & sizes & ! h\sehold] %\ld make a record ( voltage1 wattage1 & %ape ( ! lamps :i* he f9ds satisfactory 9 ! v>i\s fixtures4 ,! ,mazda daylight lamp has sev]al places 9 ! home & ! ,mazda :ite-glass & o!r high-effici5cy lamps supply _m ne$s bett] ?an ! vacuum lamps4 ,9 brackets & o!r purely decorative light+-units small fro/$ lamps are usually ! mo/ satisfactory4 ,!re is a g5]al desire = ! w>m yell[i% light ( ! c&le-flame1 & ?is may be obta9$ by a t9t$ %ade b usually m satisfactorily by means ( a t9t$ lamp4 ,! h\sehold] w f9d x int]e/+ to become intimate ) light+1 = x c s]ve him well4 ,! h\sewife w (t5 f9d mu* int]e/ 9 mak+ %ades ( textiles & ( p>*m5t4 ,*>m+ glassw>e 9 appropriate t9ts & pa9t$ designs is available = all rooms4 ,9 ! b$*amb] & ! nurs]y "s ( ^! pa9t$ designs are exce$+ly effective4 ,fixtures %\ld %ield ! lamps f ! eyes1 & ! diffus+ m$ia :e!r glass or textile %\ld be d5se en\gh to prev5t gl>e4 ,no fixture c be beautiful & no light+ effect c be arti/ic if gl>e is pres5t4 ,if ! ar*itect & ! h\sehold] w realize t light is a m$ium comp>able ) ! decorator's m$ia1 bett] light+ w result4 ,light has ! great advantage ( be+ mobile & ) adequate outlets & controls supplem5t$ by fixtures f :i* diff]5t effects are available1 ! h\sehold] w f9d 9 light+ "o ( ! mo/ fruitful s\rces ( int]e/ & pleasure4 ,x c d mu* t[>d express+ ! ta/e ( ! h\sehold] or if neglect$ x c undo mu* ( ! effect ( excell5t decoration & furni%+4 ,artificial light+1 s(tly diffus$ & prop]ly localiz$1 is "o ( ! mo/ important factors 9 mak+ a h\se a home4 ,,xxv ,,light+--,a ,,f9e ,,art8 ,9 ! prec$+ *apt]s ! progress ( light has be5 sket*$ f its obscure infancy to its vigor\s y\? ( ! pres5t "t4 ,x has be5 se5 t progress 0 sl[ until ! beg9n+ ( ! n9ete5? c5tury1 aft] :i* x began to ga9 mom5tum until ! pres5t c5tury has witness$ trem5d\s advances4 ,until ! latt] "p ( ! n9ete5? c5tury artificial light 0 consid]$ an exp5sive utility1 b z mod]n lamps appe>$ :i* suppli$ adequate light at reasonable co/ att5tion began to be c5t]$ ^u utilization1 & ! light+ eng9e] 0 born4 ,gradually x is be+ realiz$ t artificial light is no long] a luxury1 t x may be us$ 9 great quantity1 & t x may be direct$1 diffus$1 & alt]$ 9 color z desir$4 ,al?\gh ! pot5tiality ( light has be5 b>ely drawn ^u1 ! pres5t usages surpass ! mo/ extravagant dreams ( civiliz$ be+s a half-c5tury ago4 ,m]e light ( t "t 0 *ang$ into m light z gas-light+ develop$1 & m light has increas$ to adequate light ( ! pres5t "t ?r\gh ! "w ( sci5ti/s4 ,x is app>5t t a sudd5 en=c$ rev]sion to ! primitive flames ( fifty ye>s ago w\ld p>alyze _m activities4 ,mu* ( int]e/ & beauty w\ld be blott$ out ( ?is brilliant1 pulsat+1 productive age4 ,x is />tl+ to note t almo/ ! entire progress 9 artificial light+ has tak5 place dur+ ! pa/ hundr$ ye>s & t mo/ ( x has be5 cr[d$ into ! latt] "p ( ?is p]iod4 ,9 fact1 its developm5t s9ce x began 9 e>ne/ has gone =w>d ) ev]-increas+ mom5tum4 ,on view+ ! wond]s ( mod]n artificial light+ on e h& x is n difficult to mu/] ! c\rage necess>y to v5ture into its future4 ,! light+ eng9e] has be5 a natural evolution ( ! pres5t age1 = ! economic aspects ( light+ h dem&$ att5tion4 ,he is increas+ ! safety1 effici5cy1 & happ9ess ( mank9d & civilization is beg9n+ to feel 8 influ5ce economically4 ,h[ev]1 ) ! adv5t ( adequate1 effici5t1 & controllable light1 ! pot5tiality ( light z an arti/ic m$ium may be drawn ^u & ! light+ arti/ ) a deep insight into ! possibilities ( artificial light n[ has 8 opportunity4 ,b ! arti/ :o believes t a new art may be evolv$ to p]fection 9 a few ye>s is doom$ to disappo9tm5t1 = x is necess>y only to view retrospectively su* arts z pa9t+ & music to be conv9c$ t und]/&+ & appreciation develop sl[ly ?r\gh c5turies ( exp]im5t & contact4 ,w light+ ev] become a f9e art8 ,w x ev] be able alone to ar\se emotional man z d ! f9e arts8 ,are ! p[]s ( light suffici5tly great to en?rall mank9d )\t ! aid ( =m1 music1 action1 or spok5 words8 ,x is saf] to answ] yes ?an no to ^! que/ions4 ,pa9t+ has rea*$ a high place z an art & ?is art is ! expressiv5ess ( second>y or reflect$ light re9=c$ by imitation =ms1 :i* by a comb9ation ( light & draw+ comprise ! subjects4 ,a pa9t+ is a mom5t>y expression ( light1 a cross-section ( some?+ mobile1 su* z nature1 ?\ght1 or action4 ,light has ! ess5tial qualifications ( pa9t+ ) ! advantages ( a great] range ( brightness1 ( great] purity ( colors1 & ! great pot5tiality ( mobility4 ,if light+ becomes a f9e art x w d\btless be relat$ to pa9t+ some:at 9 ! same mann] t ar*itecture is ak9 to sculpture4 ,) ! introduction ( mobility x w borr[ some?+ f ! arts ( succession & especially f music4 ,! art ( light+ 9 its pres5t infancy is lean+ ^u e/abli%$ arts1 j z ! infant le>ns to walk alone by fir/ dep5d+ ^u support4 ,! use ( color 9 pa9t+ develop$ sl[ly1 be+ support$ = c5turies by ! /r5g? ( draw+ or subject4 ,! l&scapes ( a c5tury ago 7 dull1 = color 0 employ$ hesitat+ly & sp>+ly4 ,! colors 9 ! portraits ( ! pa/ m]ely repres5t$ ! gorge\s dress ( bygone days4 ,b ! pa9t] ( ! pres5t %[s t color is beg9n+ to be us$ = itself & t ! pa9t] is no long] hesitant conc]n+ its p[] to g h& 9 h& ) draw+4 ,draft+ & color+ are n[ 9 p>tn]%ip1 ! =m] hav+ giv5 up gu>dian%ip :5 ! latt] rea*$ maturity4 ,light+ is n[ an accompanim5t ( ! drama1 ( ! dance1 ( ar*itecture1 ( decoration1 & ( music4 ,x has be5 a backgr\nd or a "p ( ! atmosph]e except+ occasionally :5 "s "o ) imag9ation & d>+ has giv5 x ! lead+ rle4 ,ev5 9 its infancy x has on occasions p]=m$ admirably almo/ )\t any aid4 ,! bur/+ rocket1 ! m>vel\s effects at ! ,panama-,pacific ,exposition1 & "s ( ! exhibitions on ! !atrical /age are glimpses ( ! pot5tiality ( light4 ,to fall back ^u ! t]m9ology ( music1 ^! may be glimm]+s ( light-symphonies4 ,h>mony is simultaneity & a pa9t+ 9 ?is respect is a *ord--a mom5t>y expression fix$ 9 mat]ial m$ia4 ,a melody ( light requires succession j z ! melody 9 music4 ,! re/less colors ( ! opal comprise a light melody l ! songs ( birds4 ,! gorge\s spl5dor ( ! sunset comp>es 9 magnitude & 9 its v>i\s moods ) ! symphony or*e/ra & its p[]s4 ,?r\gh\t nature are to be f\nd g5tle *ords1 beautiful melodies & p[]ful symphonies ( light & ?is music ( light exhibits ! complexity & /ructure analog\s to music4 ,!re is no physical relation betwe5 music1 poetry1 & light1 b x is easy to lean ^u ! e/abli%$ t]m9ology = purposes ( discussion4 ,^? :o w\ld build color-music id5tical to s\nd music are mak+ ! mi/ake ( />t+ ) a physical f\ndation in/ead ( bas+ ! art ( light-expression ^u psy*ological effects ( light4 ,9 o!r words1 a relation betwe5 light & music c exi/ only 9 ! psy*ological realm4 ,^! melodies & symphonies ( light 9 nature are admitt$ly pleas+ or impressive z ! case may be1 b are !y z appeal+ z music1 poetry1 pa9t+1 or sculpture8 ,! cons5sus ( op9ion ( a l>ge gr\p ( av]age p]sons might indicate a negative reply1 b ! comb9$ op9ion ( ?is gr\p is n s valuable z ! op9ion ( a colori/ or ( an arti/ :o has s5s$ ! wond]s ( light4 ,! unprejudic$ op9ion ( arti/s is t light is a p[]fully expressive & impressive m$ium4 ,! psy*ologi/ w likely /ate t ! emotive value ( light or color is n comp>able to ! appeal ( an excell5t d9n] or ( _m o!r commonplace ?+s4 ,b he has exp]im5t$ only ) s+le colors or ) simple patt]ns & 8 subjects are select$ m or less at r&om f ! multitude4 ,:at w\ld be 8 conclusion if he exam9$ pa9t]s & o!rs :o h develop$ _! s5sibilities to a deep appreciation ( light & color8 ,x is c]ta9 t ! pa9t] :o picks up a purple petal fall5 f a rose & places x ^u a gre5 leaf is z ?rill$ by ! p[]ful vibrant color-*ord z ! musician :o he>s an exquisite h>mony ( s\nds4 ,music has be5 pres5t$ to civiliz$ mank9d 9 an organiz$ mann] = ages & ! fundam5tal physical basis ( mod]n music is a ?\s& ye>s old4 ,w\ld ! primitive savage appreciate ! mod]n symphony or*e/ra8 ,ev5 ! majority ( civiliz$ be+s pref] ! mod]n ragtime or jazz to ! exquisite art ( ! symphony4 ,an appreciation ( ! op]a & ! symphony is rea*$ by educational me?ods ext5d+ ov] long p]iods4 ,an appreciation ( ! expressiv5ess ( light _c be expect$ to be realiz$ by any %ort-cut4 ,mo/ p]sons to-day enjoy ! melodramatic movie m ?an ! drama & relatively few exp]i5ce ! deep appeal ( ! f9e arts4 ,surely ! symphony ( light _c be ju/ly condemn$ because ( a lack ( appreciation & und]/&+ ( x1 = x has n be5 introduc$ to ! public4 ,fur!rmore1 ! expressiv5ess ( music is /ill indef9ite at be/ despite ! _m c5turies ( exp]im5t+ on ! "p ( musicians4 ,if poetry is to be believ$1 ! symphonies ( light z r5d]$ by nature 9 ! sunsets1 9 ! aurora borealis1 & 9 o!r sky-effects ( great magnitude h deeply impress$ ! poet4 ,if 8 descriptions are to be accept$ at _! face-value1 ! melodies ( light r5d]$ 9 ! preci\s /one1 9 ! ice-cry/al1 & 9 ! iridesc5ce ( bird-plumage please 8 f9] s5sibilities4 ,if he is s9c]e1 mobile light is a s$uctive ag5cy4 ,! pa9t] has contribut$ little ( direct value 9 develop+ ! music ( light4 ,he is conc]n$ ) an in/antane\s expression4 ,he waits = x pati5tly &1 :ile wait+1 le>ns to appreciate ! fickl5ess ( mood 9 nature1 b :5 he fixes "o ( ^! moods he has contribut$ v little to ! art ( mobile light4 ,un=tunately ! art s*ools tea* ! /ud5t little or no?+ p]ta9+ to color = color's sake4 ,:5 ! /ud5t is capable ( draw+ fairly well & is acqua9t$ ) a few /]eotyp$ pr9ciples ( color-h>mony he is s5t =? to foll[ 9 ! foot/eps ( pa/ ma/]s4 ,he may be se5 at ! art museum fai?fully copy+ a fam\s pa9t+ or out 9 ! fields /alk+ a tree ) ! hopes ( an embryo ,corot4 ,! _w moves & has only a position 9 ! rank & file = imitators4 ,occasionally an arti/ goes to "w ) a vim & indulges 9 rese>*1 !reby demon/rat+ orig9ality 9 two respects4 ,pa9t+ is j z mu* a field = rese>* z light-production4 ,rec5tly exp]im5ts are be+ made 9 ! production ( color-h>monies devoid ( =m4 ,surely !re is a field = pure color-composition & ?is ! field ( ! pa9t] :i* leads t[>d ! art ( mobile light4 ,_m ( ! =mless pa9t+s ( ! pres5t day :i* pass "u ! bann] ( ?is ism or t are m]ely exp]im5ts 9 ! expressiv5ess ( light4 ,be+ =mless1 !y are devoid ( subject 9 ! ord9>y s5se & _c be m or less ?an a fix$ expression ( light4 ,naturally !y h receiv$ mu* criticism & h be5 ridicul$1 b !y c expect no?+ else until !y are und]/ood4 ,!y _c be und]/ood until mank9d le>ns _! language & !n !y mu/ be und]/&able4 ,9 o!r words1 !re are impo/ors ga!r$ ar\nd ! s9c]e rese>*-arti/ because ! =m] h nei!r ! ability to pa9t = a liv+ nor ! incl9ation to =sake ! comp>ative safety ( ! my/]y ( art = ! practical _w :]e _! measure w\ld be quickly tak54 ,?is army ( camp-foll[]s w n advance ! art ( mobile light1 b ! s9c]e seek]s aft] ! pr9ciples ( light-expression :o =m ! f\ndation ( ! v>i\s isms may contribute mu*4 ,! pa9t] w always be available ) 8 f9] s5sibility to appreciate & to aid 9 develop+ ! art ( mobile light1 b 8 direct contribution appe>s mo/ likely to come f ! pres5t *aos ( exp]im5ts 9 pure color-composition1 9 ! psy*ology ( light1 or1 m broadly1 9 ! expressiv5ess ( light4 ,! decorator & ! design] ( g[ns & co/umes d n arrogate to !mselves ! "n arti/1 b !y are daily creat+ some?+ :i* is lead+ t[>d a full] appreciation ( ! expressiv5ess ( light4 ,if !y d n contribute directly to ! developm5t ( ! art ( mobile light1 !y are at lea/ aid+ 9 develop+ :at may ev5tually be an appreciative public4 ,! arti/ pa9ts a /ill-life1 ! decorator creates a color-h>mony ( ab/ract or conv5tional =ms1 & ! co/um] produces a color-composition 9 textiles4 ,! decorator & co/um] approa* clos] to pure color-composition ?an ! arti/ 9 8 /ill-life4 ,! latt] is a gr\p+ ( objects prim>ily = _! color-notes4 ,:y bo!r ) a banana :5 a yell[-note is desir$8 ,:y utilize ! ab/ract or conv5tional =ms ( ! decorator8 ,:y n foll[ ?is lead fur!r to ! less def9ite =ms employ$ by ! co/um]8 ,:y n elim9ate =m ev5 m completely8 ,?is is an important po9t & an int]e/+ lead1 = to become rid ( =m has be5 "o ( ! p]plex+ problems enc\nt]$ by ^? :o h dream$ ( an art ( mobile light4 ,! pa9t] :o uses l9e & color imitatively has p]haps acquir$ skill 9 depict+ objects & m or less appreciation ( ! beautiful4 ,b if he is to be creative & to produce a high] art he mu/ be able to use l9e & color )\t ref]5ce to objects4 ,he ?us may aid 9 ! developm5t ( an ab/ract art :i* is ! high] art & at ! same "t aid 9 educat+ ! public to appreciate pure color-h>monies4 ,f ^! mom5t>y expressions ( light & f ! exp]i5ce ga9$1 ! mobile colori/ w\ld receive mat]ial aid & 8 productions w\ld be view$ by a m receptive audi5ce or r opti5ce z x may be call$4 ,! developm5t ( ta/e = ab/ract art is ne$$ 9 ord] t ! art ( mobile light may develop &1 incid5tally1 an appreciation ( ! ab/ract 9 art is ne$$ 9 all arts4 ,sci5ce has contribut$ mu* by way ( cle>+ ! decks4 ,x has produc$ ! light-s\rces & ! app>atus = controll+ light4 ,x has analyz$ ! physical aspects ( color-mixture & has accumulat$ ext5sive data p]ta9+ to color-vision4 ,x has po9t$ out pitfalls & dur+ rec5t ye>s has be5 delv+ fur!r by inve/igat+ ! psy*ology ( light & color4 ,! latt] field is look$ to = valuable in=mation1 b1 aft] all1 !re is "o way ( mak+ progress 9 ! abs5ce ( data & t is to make attempts at ! production ( impressive effects ( mobile light4 ,"s ( ^! h be5 made1 b un=tunately !y h be5 h]ald$ z f9i%$ products4 ,p]haps ! mo/ g5]al mi/ake made is 9 relat+ s\nds & colors by /ress+ a m]e analogy too f>4 ,not)/&+ ! vibratory nature ( ! propagation ( s\nd & light1 ?is is no reason = /ress+ a helpful analogy4 ,aft] all x is ! psy*ological effect t is ( importance & x is absurd to attribute any connection betwe5 light-waves & s\nd-waves bas$ ^u a relation ( physical quantities4 ,no space w be giv5 to su* a relation because x is s absurdly sup]ficial2 h[ev]1 ! language ( music w be borr[$ ) ! und]/&+ t no relation is assum$4 ,a few facts p]ta9+ to vision w indicate ! tr5d ( developm5ts necess>y 9 ! pres5tation ( mobile light4 ,! visual process syn!sizes colors & at ?is po9t dep>ts widely f ! auditory process4 ,! s5sation ( :ite may be due to ! syn!sis ( all ! spectral colors 9 ! proportions 9 :i* !y exi/ 9 noon sunlight or x may be due to ! syn!sis ( prop] proportions ( yell[ & blue1 ( r$1 gre51 & blue1 ( purple & gre51 & a va/ array ( o!r comb9ations4 ,a mixture ( r$ & gre5 lights may produce an exact mat* = a pure yell[4 ,?us x is se5 t ! mixture ( lights w cause "s difficulty4 ,= example1 ! compon5ts ( a musical *ord may be pick$ out "o by "o by ! tra9$ e>1 b if two or m color$ lights are mix$ !y are m]g$ completely & ! resultant color is g5]ally q diff]5t f any ( ! compon5ts4 ,9 music ( light1 ! compon5ts ( color-*ords mu/ be kept sep>at$1 = if !y are int]m+l$ l ^? ( musical *ords !y are indi/+ui%able4 ,!re=e1 ! elem5ts ( h>mony 9 mobile light mu/ be introduc$ by giv+ ! compon5ts diff]5t spatial positions4 ,! visual process is m sluggi% ?an ! auditory process2 t is1 lights mu/ succe$ ea* o!r less rapidly ?an musical notes if !y are to be di/+ui%$ sep>ately4 ,! e> c foll[ ! mo/ rapid execution ( musical passages1 b !re is a t5d5cy = colors to bl5d if !y foll[ "o ano!r rapidly4 ,?is critical frequ5cy or rate at :i* successive colors bl5d decreases ) ! brightness ( ! compon5ts4 ,if r$ & gre5 are alt]nat$ at a rate exce$+ ! critical frequ5cy1 a s5sation ( yell[ w result2 t is1 nei!r compon5t w be di/+ui%able & a /eady yell[ or a yell[ ( flick]+ brightness w be se54 ,! hues bl5d at a l[] frequ5cy ?an ! brightness compon5ts ( colors2 h5ce !re may be a bl5d ( color :i* /ill flick]s 9 brightness4 ,_m weird results may be obta9$ by v>y+ ! rate ( succession ( colors4 ,if ?is rate is s l[ t ! colors d n t5d to m]ge1 !y are mu* enri*$ by successive contra/4 ,x is kn[n t juxtapos$ colors g5]ally enri* "o ano!r & ?is ph5om5on is kn[n z simultane\s contra/4 ,successive contra/ causes a simil> effect ( height5$ color4 ,an effect analog\s to dynamic contra/ 9 music may be obta9$ ) mobile light by v>y+ ! int5sity ( ! light or possibly ! area4 ,melody may be simply obta9$ by m]e succession ( lights4 ,tone-quality has an analogy 9 ! v>iation ( ! purity ( color4 ,= example1 a giv5 spectral hue may be conv]t$ into a l>ge family ( t9ts by ! addition ( v>i\s am\nts ( :ite light4 ,rhy?m is z easily appli$ to light z to music1 to poetry1 to patt]n1 or to ! dance1 b 9 mobile lights its limitations already h be5 sugge/$4 ,h[ev]1 x is b\nd to play an important "p 9 ! art ( mobile light because rhy?mic exp]i5ces are mu* m agreeable ?an ^? :i* are non-rhy?mic4 ,rhy?m ab\nds ev]y:]e & no?+ s /irs mank9d f ! l[lie/ savage to ! highly cultivat$ be+ z rhy?mic sequ5ces4 ,_m psy*ological effects ( light h be5 record$ f exp]im5t & obs]vation & affective values ( light h be5 e/abli%$ 9 v>i\s o!r byways4 ,x is possible t ! degree ( pleasure exp]i5c$ by mo/ p]sons on view+ a color-h>mony or ! delightful color-melody ( a sunlit opal may be less ?an t exp]i5c$ on li/5+ to ! r5dition ( music4 ,h[ev]1 if ?is 7 true x w\ld (f] no disc\ragem5t1 because absolute values play a small "p 9 life4 ,two ev5ts :5 directly comp>$ app>5tly may diff] enorm\sly 9 _! ability to ar\se emotions1 b ! human organism is s adaptive t ea* 9 its prop] environm5t may p[]fully affect ! emotions4 ,= example1 ^? :o h sport$ 9 arial antics 9 ! heights ( cl\dl& or h /orm$ ! enemy's tr5* are /ill capable ( enjoy+ a sunset or ! call ( a bird to its mate at dusk4 ,! wond]ful adaptability ( ! inn] be+ is ! salvation ( art z well z ( life4 ,9 ! r5dition ( mobile light x is fair to give ! m$ium e advantage4 ,sometimes ?is means to elim9ate competitors & sometimes x means to remove h&icaps4 ,on ! /age light has _h competitors :i* are bett] und]/ood4 ,= example1 9 ! drama words & action are easily und]/ood1 & reg>dless ( ! effectiv5ess ( light x w\ld n receive mu* cr$it = ! emotive value ( ! production4 ,9 ! wond]ful h>mony ( music1 dance1 & light 9 c]ta9 rec5t exhibitions1 ! dance & music ov]p[]$ ! effects ( lights because !y speak famili> languages4 ,illu/ration3 ,a community ,*ri/mas tree ,a community song-fe/ival ,,artificial ,,light ,,9 ,,community ,,affairs ,illu/ration3 ,,panama-,,pacific ,,exposition ,artificial light n only reveals ! beauty ( decoration & ar*itecture b en?ralls mank9d ) its own unlimit$ p[]s ,a numb] ( attempts h be5 made to utilize light z an accompanim5t ( music & "s ( !m on a small scale h be5 s9c]e & cr$itable1 b a mu*-h]ald$ exhibition on a l>ge scale a few ye>s ago 0 n ! product ( deep ?\ght & s9c]e ef=t4 ,= example1 color$ lights ?r[n ^u a scre5 hav+ an area ( p]haps tw5ty squ>e feet 7 expect$ to compete ) a symphony or*e/ra 9 ,c>negie ,hall4 ,! music rea*$ ! mo/ di/ant auditor 9 suffici5t volume1 b ! light+ effect dw9dl$ to insignificance4 ,)\t ent]+ into c]ta9 details :i* condemn$ ! exhibition 9 advance1 ! me?od ( r5dition ( ! light-accompanim5t reveal$ a lack ( appreciation ( ! problems involv$ on ! "p ( ^? responsible4 ,incid5tally1 x has be5 %[n t ! compos] ( ?is p>ticul> musical selection ) its light accompanim5t 0 psy*ologically abnormal2 t is1 he 0 affect$ ) color$ audition4 ,x is n yet e/abli%$ to :at ext5t normal p]sons are simil>ly affect$ by light & color4 ,c]ta9ly !re is no simil>ity among ! abnormal & none betwe5 ! abnormal & normal4 ,if light is to be us$ z an accompanim5t to music1 x mu/ be giv5 an opportunity to supply atmosph]e4 ,?is x _c d if conf9$ to an insignificant spot2 x mu/ be giv5 ext5sity4 ,fur!rmore1 by ! use ( diaphan\s hang+s1 =m w be m9imiz$ & ! evanesc5t effects surely c be *>m+4 ,b f9ally ! light+ effects mu/ fill ! field ( vision j z ! music fills ! field ( audition 9 ord] to be effective4 ,!re are fundam5tal objections to ! use ( mobile light z an accompanim5t to music & !re=e ! future ( ! art ( mobile light mu/ n be all[$ to re/ ^u its success ) music4 ,if x progresses ?r\gh its relation ) music1 s mu* is ga9$2 if n1 ! relation may be brok5 = music is q capable ( /&+ alone4 ,!re is a t5d5cy on ! "p ( "s revolution>y /age arti/s to give to light+ an emotional "p 9 ! play1 or1 9 o!r words1 to utilize light+ 9 obta9+ ! prop] mood = ! action ( ! play4 ,color & purely pictorial effect are ! dom9ant notes ( "s ( !m4 ,all ( ^! mod]n /age-arti/s are ab&on+ ! intricately reali/ic sett+1 &1 z a consequ5ce1 light is enjoy+ a great] opportunity4 ,9 ! m common & %all[ !atrical production1 light+ & color effects h _m times sav$ ! day1 &1 al?\gh ^! effects are n ( ! deep] emotional type1 !y may add a spectacul> beauty :i* br+s applause :]e ! s++ is m$iocre & ! com$y isn't com$y4 ,! pot5tiality ( light+ effects = ! /age has be5 b>ely drawn ^u1 b z ! expressiv5ess ( light is m & m utiliz$ on ! /age1 ! art ( mobile light w be advanc$ j s mu* m4 ,light1 color1 & d>kness h _m emotional sugge/ions :i* are easily und]/ood & utiliz$1 b ! bl5d+ ( mobile light ) ! action is difficult because its language is only fa9tly und]/ood4 ,x is futile to attempt to describe a future composition ( mobile light4 ,c]ta9ly !re is an ext5sive v>iety ( possibilities4 ,a sunset may be compress$ into m9utes or an opalesc5t sky may be a motif4 ,v>y+ int5sities ( a s+le hue or ( alli$ hues may s]ve z a g5tle melody4 ,reali/ic effects may be introduc$4 ,! expressiv5ess ( individual colors may be tak5 z a basis = con/ruct+ ! v>i\s motifs4 ,^! may be wov5 into melody 9 :i* rhy?m bo? 9 "t & 9 int5sity may be introduc$4 ,action may be easily sugge/$ & ! numb] ( diff]5t colors1 9 a broad s5se1 :i* are visible is comp>able to ! audible tones4 ,%ad+ is z easily accompli%$ z 9 music & ! developm5t ( ?is art ne$ n be inhibit$ by a lack ( me*anical devices & light-s\rces4 ,! tools w be =?com+ if ! consci5ti\s arti/ reque/s !m4 ,:atev] ! future ( ! art ( mobile light may be1 x is c]ta9 t ! utilization ( ! expressiv5ess ( light has b>ely begun4 ,x may be t light-music mu/ pass ?r\gh ! ragtime /age ( fireworks & musical-revue color-effects4 ,if s1 x is gratify+ to "k t x is on its way4 ,c]ta9ly x has already s]v$ on a high] level 9 "s ( ! arti/ic light+ effects 9 :i* mobility has featur$ to "s ext5t4 ,if ! art does n develop rapidly x w be m]ely foll[+ ! c\rse ( o!r arts4 ,a va/ am\nt ( exp]im5t+ w be necess>y & arti/s & public alike mu/ le>n4 ,b if x ev] does develop to ! level ( a f9e art its only rival w be music1 because ! latt] is ! only o!r ab/ract art4 ,mat]ial civilization has progress$ f> & artificial light has be5 a p[]ful influ5ce4 ,may x n be true t artificial light w be responsible = ! developm5t ( spiritual civilization to its highe/ level8 ,if mobile light becomes a f9e art1 x w be man's mo/ ab/ract a*ievem5t 9 art & x may be incomp>ably f9] & m e!real ?an music4 ,if ?is is realiz$1 artificial light 9 e s5se may well des]ve to be kn[n z ! tor* ( civilization4 ,,read+ ,,ref]5ces ,no attempt w be made to give a pret5ti\s bibliography ( ! lit]ature p]ta9+ to ! v>i\s aspects ( artificial light+1 = !re are _m articles widely scatt]$ ?r\gh _m j\rnals4 ,! ,transactions ( ! ,illum9at+ ,eng9e]+ ,society af=d ! mo/ fruitful s\rce ( fur!r in=mation2 ! ,illum9at+ ,eng9e] 7,london71 conta9s mu* ( int]e/2 & ,zeits*rift fr ,beleu*tungswes5 deals ) light+ 9 ,g]many4 ,h4 ,r4 ,d',allemagne has compil$ an elaborate ,hi/orie du ,lum9aire :i* is pr(usely illu/rat$1 & ,l4 von ,b5es* 9 8 ,beleu*tungswes5 has pres5t$ _m elaborate *>ts4 ,9 bo? ^! volumes light+ devices & fixtures f ! e>ly primitive ones to ^? ( ! n9ete5? c5tury are illu/rat$4 ,a few ( ! late/ books on light+1 9 ! ,engli% language1 are ,! ,art ( ,illum9ation1 by ,bell2 ,mod]n ,illum9ants & ,illum9at+ ,eng9e]+1 by ,ga/] & ,d[2 ,radiation1 ,light & ,illum9ation1 by ,/e9metz2 ,! ,light+ ,art1 by ,luckie%2 ,illum9at+ ,eng9e]+ ,practice1 consi/+ ( a c\rse ( lectures pres5t$ by v>i\s exp]ts "u ! jo9t auspices ( ! ,univ]sity ( ,p5nsylvania & ! ,illum9at+ ,eng9e]+ ,society2 ,lectures on ,illum9at+ ,eng9e]+1 compris+ a s]ies ( lectures pres5t$ "u ! jo9t auspices ( ,johns ,hopk9s ,univ]sity & ! ,illum9at+ ,eng9e]+ ,society2 & ,! ,range ( ,electric ,se>*light ,projectors1 by ,rey2 ,! ,electric ,arc1 by ,mrs4 ,ayrton2 ,electric ,arc ,lamps1 by ,zeidl] & ,lu/g>t51 & ,! ,electric ,arc1 by ,*ild treat ! sci5tific & te*nical aspects ( ! arc4 ,g4 ,b4 ,b>ham has furni%$ a book on ,! ,developm5t ( ! ,inc&esc5t ,electric ,lamp4 ,color & ,its ,applications1 & ,light & ,%ade & ,_! ,applications1 are two books by ,luckie% :i* deal ) light+ f unique po9ts ( view4 ,! ,language ( ,color1 by ,luckie%1 aims to pres5t :at is def9itely kn[n reg>d+ ! expressiv5ess & impressiv5ess ( color4 ,w4 ,p4 ,g]h>d has suppli$ a volume on ,! ,am]ican ,practice ( ,gaspip+ & ,gas ,light+ 9 ,build+s1 & ,le$s & ,butt]field "o on ,acetyl5e4 ,a rec5t book 9 ,fr5* by ,v4 ,trudelle treats ,lumire ,electrique et ses diffr5tes ,applications au ,?atre4 ,_m books treat ( photometry1 p[]-plants1 etc41 b ^! are omitt$ because !y deal ) phases ( light :i* h n be5 discuss$ 9 ! pres5t volume4 ,light ,en]gy1 by ,cleaves1 is a l>ge volume devot$ to light-!rapy1 g]micidal action ( radiant en]gy1 etc4 ,ref]5ces to individual articles w (t5 be f\nd 9 ! v>i\s indexes ( publications4 ,,! ,,end ,,index ,a>on1 #dc ,accid5ts3 #h2 /reet-light+ 9 relation to1 #bbe et seq42 p]c5tage 7table7 (1 due to improp] light+1 #bca ,acetyl5e3 #fb2 light-yield (1 #ajf1 #ajg1 #agj1 #ahg1 #aia ,act9ic rays3 effect (1 ^u human organism1 #bge ,africa1 public light+ 9 anci5t1 #ca ,agni1 god ( fire1 #dj ,air-pump1 #acj ,air-raids1 #bbe ,alaska1 #ah1 #bi ,al*emy1 #bj ,aleutians1 #ah ,alex&ria1 #dc1 #afc ,allyl5e1 #ajf ,alum9um1 #ajh1 #agi1 #ahj ,ami5s1 ,treaty (1 #fi ,amyl5e1 #ajf ,anil9e dyes1 #ajf ,animal3 di/9ction betwe51 & human be+1 #c2 #ae2 production ( light1 #bd et seq42 s\rces ( light1 #cj1 #ca2 oils1 #ea ,antimony1 #bid ,antio*1 #aec ,arago1 #aad1 #aif ,ar*bi%op ( ,cant]bury1 #di ,ar*im$es1 #ai ,arc3 lamps1 #fi1 #hi2 electric1 #aaa et seq42 di/9ction betwe5 sp>k &1 #aab2 ,davy's notes on electric1 #aac2 =mation (1 #aae1 #aaf2 ,/aite & enclos$1 #aag1 #aah2 pr9ciple ( enclos$1 #aah1 #aai2 types (1 #abj2 flame-1 #aba1 #abb2 lum9\s1 #abb2 electric1 #abg2 lum9\s effici5cy ( electric 7table71 #abd2 #afj et seq42 -lamp 9 ligh?\ses1 #afh et seq42 magnetite-1 #ahg2 #bfa ,ardois sy/em ( signal+1 #aii ,arg&1 ,ami3 #eb2 inaugurates new era 9 artificial light+1 #ec1 #ed2 #fc1 #gj1 #gf1 #gg1 #gh1 #ig1 #afg1 #aif ,argon1 #acg ,ari/ophanes1 ,! ,cl\ds1 #ai ,art ,museums1 #i1 #ac1 #cbb1 #cbc ,asbe/os1 #agj ,asia3 public light+ 9 anci5t1 #ca1 #ci ,automobiles1 #bch ,babylon1 #ci ,bact]ia3 effect ( artificial light ^u1 #bgb et seq42 #bha1 #bhb ,bailey1 ,pr(4 ,l4 ,h41 #bej ,baltimore1 #ih ,bamboo3 c>bon filam5ts1 #afi ,b>?oldi1 #cjb1 #cjc ,beacons4 ,see ,ligh?\ses4 ,beck1 #ahf ,bee*]1 #gb ,beeswax1 #ce1 #ea ,b5z5e1 #ajf ,bible1 cit$ on importance ( artificial light1 #db-dd ,bluebird1 ,!1 ,maet]l9ck1 #i ,blue-pr9ts1 #bfa ,bollman1 #ih ,bolton1 von1 #acb1 #acc ,bombs1 illum9at+1 #ahb et seq4 ,bo/on ,light1 #afd1 #afe1 #aff1 #agg ,b[dit*1 production ( reg5]ative lamp by1 #gh1 #gi ,boy ,sc\ts1 #ag ,brem]1 #abj ,bri/ol ,univ]sity1 #beb ,bru%1 #fh1 #aei ,build+1 #h ,buns51 #ha1 #he1 #hi1 #adh1 #adi ,bureau ( ,m9es3 cit$ on op5 flames1 #bcd2 #bcf ,burn+-glasses1 #ai1 #bj4 ,see also ,l5ses4 ,butyl5e1 #ajf ,byzantium1 #cd ,cs>1 #afc ,canada1 #bed ,c&le-h\r1 def9$1 #bae ,c&les3 progress &1 #g2 #be1 #bh1 #bi1 #cj1 #cc2 religi\s uses (1 #cd1 #ce2 z a mod]n light-s\rce1 #cf1 #cg2 c]emonial uses (1 #ch et seq42 #dd1 #dh1 #eg1 #hb1 #ig1 #bbb1 #bii1 #cjd ,calcium1 #ajg1 #ajh ,c>bolic acid1 #ajf ,c>bon3 #ec1 #hj1 #ha2 physical *>act]i/ics (1 #hj1 #ha2 #ij1 #ajd1 #aje1 #abh1 #abi1 #add1 #agj ,c>bon filam5t3 #abg et seq42 prep>ation (1 #abi1 #acj1 #aca2 lum9\s effici5cy (1 #aca1 #acb2 lamps1 #afa2 lamps 9 gre5h\ses1 #bej et seq4 ,c>bons1 =mation (1 #aae1 #aaf ,c>buret$ hydrog51 #ge ,c>cel1 inv5tion ( clockwork lamp by1 #ed1 #ee ,cat-gut1 #acj ,c]ia1 #he1 #aja ,*>le/on1 ,s4 ,c41 #ahe ,*>coal3 #aac2 uses (1 = electrodes1 #aae ,*>t]$ ,gas ,light & ,coke ,co41 ,london1 #gd ,*emi/ry3 artificial light &1 #bef-bfh ,*icago1 #fb1 #cjd1 #cje ,*imneys1 #ed1 #fj1 #fb ,*9a1 #ai1 #ca1 #cb ,*lorate ( pota%1 #bb ,*ri/1 #cc1 #df1 #dg ,*ri/ians1 *ildr5 ( light1 #db ,*ri/mas trees1 #dc1 #cjd ,*romium1 #bid ,*ur* ( ,engl&1 #di ,cities3 economy ( artificial light+ 9 conge/$1 #ac ,civilization3 effect ( artificial light ^u1 #d et seq42 fire &1 #ae ,cl>k1 ,p>k] &1 #aci ,clayton1 ,dr43 inv5tion ( portable gas-light by1 #fd2 quot$1 #fd1 #fe2 exp]im5ts (1 ) coal-gas1 #fg ,claude1 #adg ,cleaves1 ,dr41 quot$1 #bgf1 #bgg ,clegg1 ,samuel3 #gd2 gas-light+ accompli%m5ts (1 #ge1 #gf ,clevel&1 #aei ,cl\ds1 ,!1 ,ari/ophanes1 #ai ,coal3 #cb2 z a light-s\rce1 #ee2 supply1 #bbc2 #bbh ,coal-gas3 #fc et seq42 public light+ by1 develop$1 #gj et seq42 analytical production (1 #ajc1 #ajd2 yield (1 retort 7table71 #aje2 analysis (1 #ajf ,coal-m9es1 #bcd et seq4 ,cobalt1 #bid ,coke1 #fh1 #aje ,cologne1 #aeg1 #aeh ,colomb1 ,philip1 #aig ,color3 #i2 relation ( artificial light to1 #bhd et seq4 ,colza1 #ca1 #eb1 #afg ,combu/ion1 #hb et seq4 ,comm]ce1 #h1 #ig ,con/ant9e1 #db ,copp]1 #bfb1 #bie ,cornwall1 #fc ,cotton3 #aja2 c>bon filam5ts1 #abi1 #acj ,crom>tie1 #gh ,crookes1 #ij1 #adf ,crosley1 ,samuel1 improvem5t ( gas-met] by1 #gf ,crusies1 #cb ,dagu]re1 #beh ,danc+1 #cdf ,davy1 ,sir ,humphrey3 #cc1 #fh1 #gc2 fir/ use by1 ( *>coal = sp>k+ po9ts1 #aab2 notes (1 on electric arc1 #aac2 #aad ,daylight1 artificial1 #ab3 #bhd et seq42 application (1 #bhg ,daylight+1 #ab-ad ,dollond1 #aie ,doty1 #fa1 #afg ,drake1 ,col4 ,e4 ,l41 discov]y ( oil 9 ,p5nsylvania by1 #ef ,drummond1 ,?omas3 #aga1 #ahe1 #aif2 quot$ on signal+1 #aig ,dudgeon1 ,miss1 #bea1 #beb ,dyes1 #bef1 #bfe ,ea/ ,indies1 #bi ,eddy/one ,light1 #aff1 #afg ,edison3 & problem ( electric inc&esc5t filam5t lamps1 #abh et seq42 #abi2 quot$ on bir? ( inc&esc5t lamp1 #acj ,edw>d ,i1 #bgd ,edw>d ,,vi1 #di ,effici5cy1 effect ( artificial light ^u1 #ad ,eggs3 relation ( artificial light to production (1 #bdg1 #bdh ,egypt3 #ca2 sacr$ness ( light 9 anci5t1 #ci2 #aec1 #aie ,electric filam5t3 #ha1 #abg et seq43 approximate value (1 lamps 7table71 #ach ,electric pile3 con/ruction (1 #aaa2 #abg ,electricity3 #ac1 #bb2 z a light-s\rce1 #eg2 = home-light+1 #fb1 #hd2 #hg1 #hi2 ignition ( gas by1 #ajb2 light+ by1 #aji et seq4 ,electromagnetic waves1 #fh1 #hf1 #hg ,electromagnets1 #aad1 #aaf ,electrodes1 #aac1 #aad1 #aae et seq42 life (1 #abb ,elizabe?1 ,que51 #bgd ,engl&3 #cb2 petroleum discov]$ 91 #ef2 gas-light+ 91 #fc et seq42 #aff1 #bea1 #bgd ,erbia1 #he ,esquimaux3 #ah2 use ( artificial light by1 #ca ,e?yl5e1 #ajf ,factories3 #ac2 artificial light 91 #bci et seq4 ,f>aday1 #aac ,filam5ts1 c>bon1 #abi et seq4 ,f9s53 #bgc1 #bgd1 #bge2 on /imulat+ action ( artificial light1 #bgg2 #bgi1 #bhj ,fire3 importance (1 to man1 #e et seq42 man's dep5d5ce ^u1 #ae2 my?ical orig9 (1 #af2 mak+1 #ag et seq42 production (1 9 ! /one age1 #ah2 9 e>ly civilization1 #ai2 anci5t wor%ip (1 #bi1 #bii ,fireflies3 #bd1 #ha1 #if1 #adh1 #adi1 #aej ,fir/ ,m5 9 ! ,moon1 ,!1 ,h4 ,g4 ,wells1 cit$1 #adh ,fi%3 artificial light z bait =1 #bdi ,flame-arcs1 #abj1 #aba1 #abb1 #ahg ,flames3 #hf1 #hh1 #hi2 op51 #bcc1 #bcd et seq4 ,fl9t1 #cc ,fool's gold1 #ah ,=t ,wagn]1 #ahe ,france3 lamps 91 #ee2 e>ly gas-light 91 #gb ,fran*ot1 inv5tion ( mod]ator lamps by1 #ee ,frankl&1 #gg ,frankl91 ,b5jam93 #afe2 quot$1 #baj-bab2 #bac ,fresnel1 #afg1 #aif ,friction1 #af1 #ag ,gas3 #ac1 #bb2 discov]y ( coal1 #cb1 #cc2 e>ly uses (1 z light-s\rce1 #fc et seq42 in/allm5t (1 pipes 9 ,engl&1 #fc1 #fd2 ,%irley's report on ,natural1 #ff1 #fg2 fir/ public display (1 light+1 #fi2 co/ (1 light+1 #ga2 fir/ attempt at indu/rial1 light+1 #gb2 fir/ ,engli%1 company1 #gd2 fir/1 explosion1 #ge2 h\se1 light+1 #gf1 #gg2 #hj1 #hb2 spectrum (1 #ij2 mod]n1 light+ indu/ry1 #ig et seq42 orig9 ( light+ by1 #ih2 fir/1 works 9 ,am]ica1 #ih2 gr[? (1 consumption 9 ,unit$ ,/ates1 #ii2 electrical ignition appli$ to1 light+1 #ajb2 pressure1 #ajb1 #ajc2 wat]1 #aje2 c>bons 91 #ajf2 production ( ,p9ts*1 #aji1 #aaj2 salts appli$ to1 flames1 #abj2 #aeg2 ,c5sus ,bureau figures on co/ (1 plants1 #bba1 #bbb2 #bbd1 #cda ,gas-burn]s3 #fc1 #fd1 #gg2 c&le-p[] ( pione] 7table71 #gi2 improvem5ts 91 #hd ,gas-mantle3 #fa1 #ha2 influ5ce (1 #ii2 *>act]i/ics (1 #ajj et seq42 #ahg ,gas-met]1 ,clegg's1 #gf ,gasol5e3 lamps1 #ee2 #eg ,gassiot1 #aad ,gauss1 #aif ,geissl]1 #adf ,g5]al ,electric ,company1 #acb1 #ace1 #acf ,g]many3 developm5t ( lamps 91 #ef2 e>ly gas-light+ 91 #gb ,glass1 #aie1 #bij et seq4 ,gl[]s1 #aci ,gl[-worms1 #bd ,glyc]ides1 #eb ,gold1 #bic ,g\t1 #bge ,gramme dynamo1 #aag ,grass3 #ah2 c>bon filam5ts1 #abi ,greece3 #ci2 sacr$ lamps 9 anci5t1 #da2 #db ,gre5h\ses1 c>bon-filam5t lamps 91 #bej et seq4 ,hall ( ,fame1 #acd ,happ9ess1 effect ( artificial light ^u1 #ad ,hayd5 & ,/e9metz1 #bec ,heal?1 artificial light 9 relation to1 #bfi-bhc ,helium1 #hi ,hemig1 #aee ,hemp1 #ba ,h5ry1 ,william1 #ge ,h]odotus1 #ef ,h]tz1 #fh ,h]tzian waves1 #bga ,hewitt1 ,coop]1 produces m]cury-arcs1 #abd1 #abe ,home3 artificial light 9 relation to1 #f2 light+1 #cbe et seq4 ,h9du3 light 91 c]emonials1 #dj ,hudson-,fulton ,celebration1 #cjf ,huyg5s1 #aie ,hydroc>bons1 #hb ,hydrog51 #ha ,illit]acy1 artificial light &1 #i ,inv5tion1 #g1 #ig ,i[a1 #bch ,iridium1 #abi ,iron1 #ah1 #bfb1 #bid ,iron pyrites1 #ah ,italy1 #bdi ,jablo*kov3 electric c&le (1 #aag ,jamaica1 #ai ,j&us1 #aah1 #abb ,japan3 #ai2 use ( oil 91 #cj2 #bha ,j]usalem1 #dc ,jews3 artificial light among1 #dj ,j\rnal1 ,p>is1 quot$1 #baj-bab ,k]os5e3 #eg2 weight (1 lum5s1 #fj2 #fb1 #ahg1 #bcc ,kitson1 plat9um-gauze mantle appli$ by1 #fa ,laboratories3 a*ievem5ts (1 #acg ,lamps3 #af1 #be2 ,roman1 #cj2 #ca2 inv5tion ( safety1 #cc2 anci5t fun]eal1 #ci2 sacr$1 ( antiquity1 #da2 c]emonial1 #dd2 sci5tific developm5t ( oil1 #ea et seq42 ,holliday1 #ee2 ,c>cel1 #ed1 #ee2 ,fran*ot's mod]ator1 #ee2 gasol5e1 #ee2 developm5t (1 9 ,g]many1 #ef2 air pressure1 #fa2 supremacy ( oil1 ends1 #fb2 ,b[dit*'s1 #gg1 #gh2 #hj1 #ig2 m]cury-arc1 #abf2 electric inc&esc5t filam5t1 #abg et seq42 gem1 #acb2 tung/51 #acc et seq42 lum9\s effici5cy 7table7 ( inc&esc5t filam5t1 #ada2 #bii2 9 home1 #cbh-ccc ,lange1 #afg ,l>d-oil1 #ea ,lavoisi]1 #aie ,lead1 #bfb1 #bid ,le ,bon1 #gb ,leg5d ( ,montrose1 ,!1 ,scott1 cit$ on primitive light+1 #bg ,leigh1 ,edmund1 quot$1 #bbf ,l5ses1 #bj1 #aga et seq4 ,libanius1 quot$1 #aec1 #aed ,lib]ty1 ,/atue (1 #cja1 #cjb1 #cjc ,libr>ies1 #i ,light3 relation ( artificial1 to progress1 #c et seq42 z a civiliz+ ag5cy1 #c-ad2 primitive man & artificial1 #d2 ,milton1 quot$ on importance (1 #e2 artificial1 & sci5ce1 #g2 artificial1 & indu/rial developm5t1 #h2 ,maet]l9ck's tribute to1 #i2 ,l9coln's debt to artificial1 #i2 symbolism (1 #i1 #aj2 !rapy1 #aj2 9 w>1 #aa2 adaptations (1 #ab2 #ac2 my?ical orig9 ( artificial1 #af2 e>lie/ s\rce (1 #af2 production (1 9 /one age1 #ah2 mat*es z s\rce (1 #ba2 animals z1 s\rces1 #bd1 #be2 primitive s\rces (1 #bd-cg2 evolution ( artificial1 s\rces1 #bd-cg2 developm5t1 #bh et seq42 e>ly outdoor use ( artificial1 #bh2 ,roman uses ( artificial1 #cj2 beg9n+ ( sci5tific1 #cc1 #cd2 c&les z mod]n1 s\rce1 #cf1 #cg2 symbolism & religi\s uses (1 #ch et seq42 ,bible cit$ on artificial1 #db-dd2 9 relation to wor%ip1 #dc1 #de1 #df2 ,arg&'s contribution to1 #ec1 #ed2 coal z1 s\rce1 #ee2 e>ly uses ( gas z1 s\rce1 #fc et seq42 z a public utility1 #gj2 fir/ in/allation ( indu/rial gas1 #gb2 sci5ce (1 production1 #hj et seq42 causes (1 radiation1 #hj1 #ha2 #hc2 lime1 #hd2 electric1 #hi et seq42 pr9ciple (1 production1 #ij1 #ia2 s\rces1 #ic2 v>i\s gas-burn]s'1 supply1 #ie2 relative effici5cy (1 s\rces1 #ie1 #if2 9 ! home1 #ig2 influ5ce (1 ^u sci5ce1 inv5tion1 & comm]ce1 #ig et seq42 yield ( acetyl5e1 #ajf1 #ajg2 electric1 #aji2 influ5ce ( gas ^u developm5t ( artificial1 #aaj2 developm5t ( artificial1 #aaa et seq42 ef=ts to improve color ( m]cury-arc1 #abe2 electric-inc&esc5t-filam5t1 #abg et seq42 effect ( tung/51 ^u1 #acc et seq42 ( ! future1 #adc-aeb2 9 w>f>e1 #agh-aic2 signal+1 #aid-bjg2 co/ (1 #bjh-bbd2 & safety1 #bbe et seq42 improp] use (1 #bbi1 #bcj2 comp>ison ( daylight & artificial1 #bdj2 r$uc+ action (1 #beh2 bact]icidal action (1 #bgb et seq42 modify+1 #bhd et seq42 spectacul> uses (1 #bih-cji2 expressiv5ess (1 #caj-cbd2 utility ( mod]n1 #cbe-cdj2 evolution ( ! art ( apply+1 #cda-cef2 mobile1 #cdg1 #cdh1 #cdi1 #cej2 psy*ological effect (1 #cea et seq42 z an accompanim5t to music1 #ceb-ced ,light-buoys1 #aj1 #afi ,ligh?\ses3 #aj1 #afc-agg2 optical app>atus (1 #agb et seq4 ,light-%ips1 #aj1 #afi ,light+-sy/ems3 comp>ison (1 #ab-ad ,lime1 #hd1 #ajg1 #ajh1 #bid ,l9coln1 ,abraham1 #i ,l951 #ah ,l9k-buoys1 #bh ,li?opone1 #bfe1 #bff ,liv]pool1 #afg ,liv+3 comp>ison (1 /&>ds1 #bch et seq4 ,london1 #aeb1 #aed1 #aee1 #aef1 #aeg1 #bjb ,london ,gas ,light & ,coke ,company1 #gd ,lucig51 #fa ,lum5-h\r3 def9$1 #bae ,lum5s3 #fj1 #id1 #bae ,lu!ran ,*ur*1 #di ,lyceum ,!atre1 ,london1 #gc ,maet]l9ck1 ,maurice1 #i ,magaz9es1 #h ,magdsick1 ,h4 ,h41 #cjc ,magnesia3 #hd2 ,n]n/'s application (1 #ach ,magnesium1 #agi1 #ahj ,magnetite arc1 #ahg ,man3 di/9ction betwe51 & animal1 #c2 artificial light & e>ly1 #d2 light-s\rces ( primitive1 #be ,manganese1 #bfb1 #bfh1 #bid ,mang91 #ahh ,mann1 #abi ,mantles1 #ie ,manufactur+1 #h ,m>coni1 #fh ,m>ks1 #aah ,mat*es3 z light-s\rces1 #ba2 #bb1 #hb ,maxwell1 #fh ,mazda lamps1 #bhi1 #cci ,mecca1 #dj ,m$it]ranean ,sea1 #afc ,m]cury-arc3 ,way's1 #abd2 #abe1 #abf2 qu>tz1 #abe1 #abf2 attempts to improve color (1 light1 #abe ,middle ,ages1 #df1 #dg1 #dgd ,milton1 quot$1 #e ,mirror1 #ai ,mohamm$ans1 #dj ,moore1 ,dr4 ,mc,farlan1 #adf1 #adg ,morality1 effect ( light ^u1 #i ,morse code3 application (1 to light-signal+1 #aih1 #aii ,moses1 #aie ,mov+-pictures1 #i1 #bfj1 #bfa ,muni*1 #gb ,murdock1 ,william3 in/allm5t ( gas-pipes by1 #fc2 #fh1 #fi1 #gj2 quot$ on indu/rial use ( artificial1 #ga2 #gb1 #gc1 #gd1 #gf1 #gh1 #bag1 #cji ,museums3 #ac2 utilization ( artificial light by1 #cbb1 #cbc ,music3 light z an accompanim5t to1 #ceb-ced ,my?ology1 #af ,nantes1 #he ,napoleon1 #aaa ,nap?al5e1 #ajf ,national ,heat & ,light ,co41 #gb1 #gd ,natural gas1 #ii ,naves9k ,light1 #bjf ,n]n/1 #ach1 #aci ,newspap]s1 #h ,newton1 ,sir ,isaac3 #g2 quot$ on discov]y ( visible spectrum1 #hg2 #hh ,new ,york1 #ih1 #afe1 #aff1 #bjf1 #cjb1 #cjd ,niag>a ,falls1 #ajh1 #cjf ,nickel1 #bfb ,nielson1 #gg ,niepce1 #beh ,nit]1 #ba ,nitrog51 #acg ,norfolk1 #afi ,obesity1 #bge ,(fices1 #ac ,oil3 z a light-s\rce1 #bi et seq42 developm5t (1 lamps1 #ea et seq42 #aee2 9 ligh?\se1 #afe et seq42 #bbb1 #bbd1 #bii ,o',le>y1 ,mrs41 & h] lamp1 #fb ,olive-oil1 #ea1 #eb1 #afg ,orkney ,isl&s1 #bi1 #agg ,osmium1 #acc ,oxyg53 relative consumption (1 by oil-lamps1 #eh1 #ei2 #bfb ,ozone1 #bfb ,pa9t+1 #cdb1 #cdc1 #cdg1 #cdh1 #cdi ,pall ,mall1 #gd ,panama-,pacific ,exposition3 #cjd2 artificial light+ (1 #cjf1 #cjg1 #cjh1 #cji ,pap]3 #ah2 c>bon filam5ts1 #abi1 #acj ,p>aff91 #ce1 #eg ,p>k] & ,cl>k1 #aci ,p>is3 exp]im5tal gas-light+ 91 #hc1 #hd2 ,volta 91 #aaa2 #aed1 #ahe1 #baj1 #bab1 #bac ,peckham1 ,john1 #aie ,p5nsylvania3 discov]y ( oil 91 #ef ,p]iodic ,law1 #ade ,petroleum3 #ce1 #ea1 #ee2 discov]y (1 #ef2 con/itution ( crude1 #eg2 #eh1 #bad ,ph>os1 #afc ,philadelphia1 #ih1 #ii1 #aeg ,phillips & ,lee1 #gj1 #gb ,philosophical ,transactions ( ! ,royal ,society ( ,london1 #cc2 quot$ on indu/rial light+1 #fc2 ,%irley's report on natural gas 91 #ff1 #fg2 quot$1 #hg ,pho5icians1 #cd1 #ci ,phosphorus1 #ba ,photo-micrography1 #ab ,photography3 #abf2 e>ly exp]im5ts 91 #beh2 developm5t (1 #bei2 #bia1 #bib ,picric acid1 #ajf ,pigm5ts1 #bfe ,p9ts*3 production (1 gas1 #aji1 #aaj1 #agj ,pit*1 #ajf ,plant-gr[?3 artificial light &1 #aa1 #bdi et seq4 ,plat9um1 #he1 #abh1 #abi1 #bfb ,plumbago1 #aac1 #acj ,plym\?1 #aff ,poetry1 #cdf ,police1 #afb ,pota%1 *lorate (1 #bb ,prie/ley1 ,pr(essor1 quot$1 #beb ,pr9t+1 #h ,progress3 influ5ce ( fire ^u1 #ae et seq4 ,prome!us1 #af1 #da ,propyl5e1 #ajf ,ptolemy ,,ii1 #afc ,qu>tz3 #ah1 #ai2 m]cury-arcs1 #abe2 uses (1 #abf2 9 sk9 diseases1 #bgh1 #bgi ,radiators1 en]gy1 #hh et seq4 ,radium1 #aej ,railway ,signal ,association1 #bje ,railways3 light-signal+ appli$ to1 #bje ,ramie fib]1 #aja ,rane1 #bej1 #bea ,r>e-e>? oxides3 #he2 prop]ties (1 #hh1 #ii ,recreation1 #i ,r$ru?1 #fc ,re=mation3 c]emonial uses ( light dur+ !1 #dh1 #di ,rheumatism1 #bge ,rob9s1 ,b5jam91 #bja ,rome1 #cj1 #cb1 #cd1 #ci1 #da1 #db1 #dd ,rntg51 #bgj1 #bhj4 ,see also ,x-ray4 ,royal ,society ( ,london3 #cc1 #fc1 #ff1 #fg1 #gj1 #gc2 & fir/ gas explosion1 #ge1 #aaa1 #aab ,rum=d1 #afg ,ru%lights1 #bh1 #cc ,russia1 #bha ,ryan1 ,w4 ,d',a41 #cjf ,safety3 artificial light 9 relation to1 #ad1 #bbe et seq4 ,salts3 *emical1 #hh1 #hi2 metallic1 #abj2 silv]1 #beg1 #beh ,s&y ,hook ,light1 #afe1 #aff ,san ,francisco1 #cjd1 #cjf-cji ,savages1 #c1 #ae1 #ag ,sawy]1 #abi ,s*eele1 ,k4 ,w41 #acc2 quot$1 #beg1 #beh ,s*ools1 #i ,sci5ce3 light &1 #f1 #g2 #ig2 sy/ematiz$1 #bfh ,scotl&3 #bf1 #ca1 #cb1 #dh2 oil indu/ry 91 #ef ,scott1 ,sir ,walt]1 cit$1 #bg1 #ih ,sculpture3 artificial light 9 relation to1 #ahd ,se>*-lights1 #aa1 #afi ,section ( ,plant ,protection1 #bbe1 #bbf ,sel5ium1 #bfg1 #bic ,semaphore1 #aii ,%ells3 illum9at+1 #agi et seq4 ,%irley1 ,?omas3 quot$ on natural gas1 #ff1 #fg ,siem5s1 #gh ,signal+1 #aid-bjg ,silicon3 filam5t1 #adj ,silk3 artificial1 #aja2 c>bon-filam5ts1 #abi ,simpson1 ,r4 ,e41 #bbg1 #bca ,silv]1 #beh1 #bic ,sk9 diseases3 treatm5t (1 #bgh1 #bgi1 #bhj ,skylights1 #ac ,sleep1 #h ,smallpox1 #bgd1 #bge ,smeaton1 #aff ,soho1 #fi1 #gb ,s\? ,africa1 #abi ,sp>ks3 #cc1 #abe ,spectrum3 visible1 #hf2 ,newton quot$ on1 #hg2 ( elem5ts1 #hi2 ( gases1 #ij2 #abj1 #aba2 m]cury1 #abd-abf ,sp]m1 #ca1 #ea1 #eb1 #afg ,sp]maceti1 #ce1 #ea ,spl9t]-hold]s1 #bg1 #bh ,/age3 & artificial light1 #cai et seq42 #cdc ,/aite1 #aag1 #aah ,/e>9e1 #ce1 #eb ,/e>n1 #abi ,/eel1 #ah1 #cc ,/e9metz1 ,hayd5 &1 #bec ,/]ilization3 qu>tz-m]cury-arc &1 #bhj1 #bha1 #bhb ,/ev5son1 ,rob]t ,l\is1 quot$1 #agg ,/ores1 #ac ,/4 ,paul1 #dc ,/4 ,paul's ,ca!dral1 #cjj ,/reet-light+3 developm5t (1 #aeb-afb ,sug>1 #bb ,sulphide ( iron1 #ah ,sulphur1 #ah1 #ba1 #agi1 #ahj1 #bid ,sulphuric acid1 #ba1 #bb ,sun1 #h1 #af1 #ai1 #bj ,swan1 #abi ,syracuse1 #ai ,syria1 #aec ,tall[1 #cd1 #ce1 #ea1 #eb ,tantalum3 #acb2 filam5t lamps1 #acc ,t>1 #fh1 #ajf ,telegraphy1 #aie ,telephony1 #aid ,textiles1 #bef ,?ames1 #afi ,!at]s1 #i1 #cai et seq4 ,?oria1 #he ,t91 #bfb ,t9d]-boxes1 #ah1 #ai1 #bb ,travel]s ,insurance ,company1 #bbg ,trees1 #bf ,troy1 #db ,tub]culosis1 #bgc ,tung/5 lamp1 #afa et seq41 #ahg1 #bfa1 #bij1 #cjc ,typhus1 #bgc ,ultra-violet rays3 #abf1 #aej2 9 photographic electricity1 #bfg1 #bfh2 #bgj1 #bgb1 #bid ,unit$ ,/ates3 petroleum 91 #eg2 gas-consumption 91 #ii2 #afd1 #afe1 #aff ,unit$ ,/ates ,geological ,survey1 cit$ on sale ( gas1 #bbb ,unit$ ,/ates ,milit>y ,intellig5ce1 #bbe1 #bbf ,vacuum tubes1 #ha1 #bhf ,v5etians1 #aie ,v5tilation1 #ac ,v]ne1 ,jules1 #adc ,ve/al ,virg9s1 #db ,volcanoes1 #aff ,volta1 #aaa1 #aab1 #abg ,voltaic pile3 con/ruction (1 #aaa1 #abg ,von ,bolton4 ,see ,bolton4 ,w>3 & artificial light1 #aa1 #agh-aic ,wa%+ton1 #cje ,wat]3 /]ilization (1 by artificial light1 #bhj et seq4 ,watson1 ,dr4 ,ri*>d1 #fg1 #fh ,watt1 #id ,waves3 electro-magnetic1 #fh1 #hf1 #abe et seq4 ,wax1 #cd1 #df1 #ea ,way3 m]cury-arc produc$ by1 #abd ,wells1 #fa ,wells1 ,h4 ,g41 cit$1 #adh ,welsba*1 ,au] von3 #fa2 inv5tion ( mantle by1 #ii1 #ajj1 #acc ,w5ham1 #gh ,we/ ,indies1 #be ,:ale-oil1 #ca ,wicks1 #ce1 #cf1 #ec1 #ed1 #eh1 #ei ,w9sor1 #gb1 #gc4 ,see also ,w9zl]4 ,w9zl]4 ,see ,w9sor4 ,wolfram4 ,see ,tung/54 ,wood1 #bf1 #bg1 #bh ,woolwor? ,build+1 #cjb1 #cjc ,w\nds3 treatm5t (1 by artificial light1 #aj ,x-ray3 production (1 tubes dur+ ,w>1 #aca2 #acg1 #aej1 #bgj1 #bhj ,"y1 ,james3 discov]s petroleum1 #ef ,yttria1 #he ,zeitung1 ,cologne3 #aeg2 extract f1 on /reet-light+1 #aeh ,z9c1 #abe1 #acj1 #bfg ,zirconia1 #hd1 #he ,transcrib]'s ,li/ ( ,corrections ,,location ,,orig9al ,,correct$ ,*apt] ,,ii & simili> mat]ial & simil> mat]ial ,*apt] ,,xiii z a con/ant level at a con/ant level ,*apt] ,,xiv ! c>bons to di/9tegrate ! c>bons to dis9tegrate ,*apt] ,,xv ,john ,pe*ham ,john ,peckham coat$ ) an all[ coat$ ) an alloy ) v>i\s billiant ) v>i\s brilliant key 9 depress$ key is depress$ ,*apt] ,,xvi has ne>ly d\bl$ h ne>ly d\bl$ ,*apt] ,,xvii ?is own indiff]5ce _! own indiff]5ce ,*apt] ,,xxiii ,nature's light+ v>i$ ,nature's light+ v>ies ,*apt] ,,xxiv s-call$ cadelabra s-call$ c&elabra possibilties possibilities ,,read+ ,,ref]5ces 444,applications an ,?atre4 444,applications au ,?atre4 ,,index ,photo-micography ,photo-micrography ,siemans ,siem5s