:i* includes ! #bjh orig9al illu/rations4 ,see #ecejh-;h4htm or #ecejh-;h4zip3 7https3_/_/www4gut5b]g4org_/ca*e_/epub_/ #ecejh_/pg#ecejh-;images4html7 or 7https3_/_/www4gut5b]g4org_/files_/#ecej h_/ecejh-;h4zip7 ,images ( ! orig9al pages are available ?r\gh ,int]net ,ar*ive4 ,see https3_/_/ar*ive4org_/details_/airplanep hotogra#jj;ivesu(t ,transcrib]'s note3 ,text enclos$ by und]scores is 9 italics 7italics74 ,text enclos$ by equal signs is 9 bold face 7bold74 ,a c>at "* is us$ to d5ote sup]scription4 ,a s+le "* foll[+ ! c>at is sup]script$ 7example3 #ajj1jjjb74 ,an und]score foll[$ by "o or m *>act]s enclos$ by curly brackets indicates t ! ! "*7s7 )9 ! curly brackets is_/are subcript$ 7example3 ,a#a74 ,,airplane ,,photography ,illu/ration ,,airplane ,,photography by ,,h]b]t ,e4 ,,ives ,major1 ,aviation ,section1 ,signal ,(fic]s ,res]ve ,corps1 ,unit$ ,/ates ,army2 ,lately ,(fic] 9 ,*>ge ( ,exp]im5tal ,dep>tm5t1 ,photographic ,bran*1 ,air ,s]vice #bjh ,,illu/rations ,illu/ration ,philadelphia & ,london ,j4 ,b4 ,lipp9cott ,company ,copyright1 #aibj1 by ,j4 ,b4 ,lipp9cott ,company ,pr9t$ by ,j4 ,b4 ,lipp9cott ,company at ! ,wa%+ton ,squ>e ,press ,philadelphia1 ,u4 ,s4 ,a4 ,,to ,,my ,,wife ,a ,,helpful ,,critic1 ,,ev5 ,,?\gh ,,%e ,,nei!r ,,photographs ,,nor ,,flies ,,preface ,airplane photography _h its bir?1 & pass$ ?r\gh a p]iod ( fev]i% developm5t1 9 ! ,great ,w>4 ,probably to _m m9ds x figures z a purely milit>y activity4 ,su* ne$ n be ! case1 = ! application ( a]ial photography to mapp+ & o!r peace-"t problems promises soon to q ov]%ad[ its milit>y orig94 ,x has !re=e be5 ! writ]'s endeavor to treat ! subject z f> z possible z a problem ( sci5tific photography1 emphasiz+ ^? g5]al pr9ciples :i* w apply no matt] :at may be ! purpose ( mak+ photographs f ! air4 ,x is ( c\rse inevitable t :oev] at ! pres5t "t attempts a treatise on ?is newe/ k9d ( photography mu/ draw mu* ( 8 mat]ial f w>-"t exp]i5ce4 ,if1 = ?is reason1 ! problems & illu/rations ( ?is book are pr$om9antly milit>y1 x may be rememb]$ t ! dem&s ( w> are f> m sev]e ?an ^? ( peace2 & h5ce ! presumption is t an acc\nt ( h[ photography has be5 made successful 9 ! milit>y plane w s]ve z an excell5t guide to meet+ ! peace-"t problems ( ! ne> future4 ,x is assum$ t ! read] is already fairly conv]sant ) ord9>y photography4 ,consid]able space has inde$ be5 devot$ to a discussion ( ! fundam5tals ( photography1 & to sci5tific me?ods ( /udy1 te/1 & specification4 ,?is has be5 done because a]ial photography /ra9s to ! utmo/ ! capacity ( ! photographic process1 & x is necess>y t ! mo/ advanc$ me?ods be und]/ood by ^? :o w\ld secure ! be/ results or contribute to future progress4 ,no pret5ce is made t ! book is an a]ial photographic encyclopdia2 x is n a manual ( in/ructions2 nor is its appeal s popul> z x w\ld be 7 ! majority ( ! illu/rations /rik+ a]ial photographs ( w> subjects4 ,x is hop$ t ! middle c\rse /e]$ has produc$ a volume :i* w be in=mative & inspirational to ^? :o are s]i\sly int]e/$ ei!r 9 ! practice ( a]ial photography or 9 its developm5t4 ,! writ] is deeply 9 debt to _m p1 ^: assi/ance ( "o sort or ano!r has made ?is book possible4 ,fir/ ( all %\ld be m5tion$ ^? (fic]s ( ! ,engli%1 ,fr5* & ,italian armies ?r\gh ^: c\rtesy x is t he c speak at fir/ h& ( ! photographic practices 9 ^! armies at ! front4 ,x is due to ,lieut5ant ,colonel ,r4 ,a4 ,millikan t ! exp]im5tal "w ( :i* ! writ] has _h *>ge 0 initiat$ 9 ! ,unit$ ,/ates ,air ,s]vice4 ,to him & to ,major ,c4 ,e4 ,m5d5hall1 "u :om ! "w 0 organiz$ 9 ! ,sci5ce & ,rese>* ,division ( ! ,signal ,corps1 are ow+ ! writ]'s ?anks = ! opportunities & support giv5 by !m4 ,a simil> ackn[l$gm5t is made to ,lieut5ant ,colonel ,j4 ,s4 ,sullivan1 ,*ief ( ! ,photographic ,bran* ( ! ,army ,air ,s]vice1 = 8 int]e/ & enc\ragem5t 9 ! compilation ( ?is "w1 & = ! p]mission accord$ to use ! air s]vice photographs & draw+s :i* =m ! majority ( ! illu/rations4 ,! greate/ debt ( all1 h[ev]1 is to ^? (fic]s :o h =m$ ! /aff ( ! ,exp]im5tal ,dep>tm5t4 ,to m5tion !m by "n3 ,capta9 ,c4 ,a4 ,proctor1 :o 0 *>g$ ) our =eign liaison1 & :o act$ z deputy *ief dur+ ! writ]'s abs5ce ov]seas2 ,capta9 ,a4 ,k4 ,*apman1 9 *>ge ( ! "w on optical p>ts1 & lat] *ief ( our ,ro*e/] ,bran*2 ,capta9 ,e4 ,f4 ,k+sbury1 :o _h imm$iate *>ge ( cam]a developm5t2 ,lieut5ant ,j4 ,b4 ,br9smade & ,mr4 ,r4 ,p4 ,w5twor?1 :o h&l$ ! exp]im5tal "w on cam]a m\nt+s & in/allation2 ,lieut5ant ,a4 ,h4 ,nietz1 9 *>ge ( ! ,langley ,field ,laboratory ( ! ,exp]im5tal ,dep>tm5t2 ,mr4 ,r4 ,b4 ,wilsey & ,lieut5ant ,j4 ,m4 ,hammond1 :o1 ) ,lieut5ant ,nietz1 c>ri$ on ! exp]im5tal "w on s5sitiz$ mat]ials4 ,a l>ge "p ( :at is new & :at is ascrib$ 9 ! foll[+ *apt]s to 8,! ,am]ican ,air ,s]vice0 is ! "w ( ?is gr\p ( m54 ,7 individual ref]5ces made1 9 place ( ?is g5]al & inclusive "o1 _! names w\ld ?ickly spr9kle ^! pages4 ,x has be5 a r>e privilege to h associates s able1 en?usia/ic1 & loyal4 ,,! ,,au?or ,,novemb]1 #aiai ,,cont5ts ,i4 ,,introductory ,,*apt] ,,page #a4 ,,g5]al ,,survey #ae #b4 ,,! ,,airplane ,,consid]$ ,,z ,a ,,cam]a ,,plat=m #bj ,,ii4 ,,! ,,airplane ,,cam]a #c4 ,,! ,,cam]a--,,g5]al ,,consid]ations #ci #d4 ,,l5ses ,,= ,,a]ial ,,photography #dd #e4 ,,! ,,%utt] #fh #f4 ,,plate-,,hold]s ,,& ,,magaz9es #hg #g4 ,,h&-,,held ,,cam]as ,,= ,,a]ial ,,"w #ie #h4 ,,non-,,automatic ,,a]ial ,,plate ,,cam]as #ajb #i4 ,,semi-,,automatic ,,a]ial ,,plate ,,cam]as #aaf #aj4 ,,automatic ,,a]ial ,,plate ,,cam]as #abd #aa4 ,,a]ial ,,film ,,cam]as #acj #ab4 ,,motive ,,p[] ,,= ,,a]ial ,,cam]as #ade #ac4 ,,cam]a ,,auxili>ies #afc ,,iii4 ,,! ,,susp5sion ,,& ,,in/allation ,,( ,,airplane ,,cam]as #ad4 ,,!ory ,,& ,,exp]im5tal ,,/udy ,,( ,,me?ods ,,( ,,cam]a ,,susp5sion #agi #ae4 ,,practical ,,cam]a ,,m\nt+s #aic #af4 ,,in/allation ,,( ,,cam]as ,,& ,,m\nt+s ,,9 ,,planes #bjh ,,iv4 ,,s5sitiz$ ,,mat]ials ,,& ,,*emicals #ag4 ,,! ,,di/ribution ,,( ,,light1 ,,%ade ,,& ,,color ,,9 ,,! ,,a]ial ,,view #bba #ah4 ,,*>act]i/ics ,,( ,,photographic ,,emulsions #bbg #ai4 ,,filt]s #bci #bj4 ,,exposure ,,( ,,a]ial ,,negatives #bdg #ba4 ,,pr9t+ ,,m$ia #beb #bb4 ,,photographic ,,*emicals #beg ,v4 ,,me?ods ,,( ,,h&l+ ,,plates1 ,,films ,,& ,,pap]s #bc4 ,,! ,,develop+ ,,& ,,dry+ ,,( ,,plates ,,& ,,films #bfg #bd4 ,,pr9t+ ,,& ,,enl>g+ #bgi ,,vi4 ,,practical ,,problems ,,& ,,data #be4 ,,spott+ #bia #bf4 ,,map ,,mak+ #cjd #bg4 ,,oblique ,,a]ial ,,photography #cbj #bh4 ,,/]eoscopic ,,a]ial ,,photography #cbi #bi4 ,,! ,,int]pretation ,,( ,,a]ial ,,photographs #cea #cj4 ,,naval ,,a]ial ,,photography #cfh ,,vii4 ,,! ,,future ,,( ,,a]ial ,,photography #ca4 ,,future ,,developm5ts ,,9 ,,app>atus ,,& ,,me?ods #chc #cb4 ,,te*nical ,,& ,,pictorial ,,uses #chh #cc4 ,,exploration ,,& ,,mapp+ #dja ,i ,,introductory ,,airplane ,,photography ,,*apt] ,i ,,g5]al ,,survey ,a]ial ,photography f ,balloons & ,kites4--,photography f ! air _h be5 develop$ & us$ to a limit$ ext5t be=e ! ,great ,w>1 b ) v few exceptions ! "w 0 done f kites1 f balloons1 & f dirigibles4 ,a]ial photographs ( ,european cities _h figur$ to a small ext5t 9 ! illu/ration ( guidebooks1 & "s a]ial photographic maps ( cities _h be5 made1 notably by ! ,italian dirigible balloon s]vice4 ,kites _h be5 employ$ ) success to c>ry cam]as = photograph+ su* objects z active volcanoes1 ^: ph5om5a c\ld be obs]v$ ) unique advantage f ! air1 & ^: location 0 usually f> f balloon or dirigible facilities4 ,z a result ( ?is pre-w> "w we _h a*iev$ "s k ( real sci5tific value z to photographic conditions f ! air4 ,notable among ^! discov]ies 0 ! exi/5ce ( a veil ( haze ov] ! l&scape :5 se5 f high altitudes1 & ! consequ5t ne$ = s5sitive emulsions ( consid]able contra/1 & = color-s5sitive plates to be us$ ) color filt]s4 ,! developm5t ( a]ial photography w\ld probably h[ev] h advanc$ b little _h x dep5d$ m]ely on ! balloon or ! kite4 ,z cam]a c>ri]s _! limitations are s]i\s4 ,! kite & ! captive balloon _c navigate f place to place 9 su* a way z to p]mit ! rapid or cont9u\s photography ( ext5d$ areas4 ,! kite suff]s because ! cam]a x supports mu/ be manipulat$ ei!r f ! gr\nd or else by "s elaborate me*anism1 bo? = po9t+ & = h&l+ ! expos+ & plate *ang+ devices4 ,! free balloon is at ! m]cy ( ! w9ds bo? z to its direction & its spe$ ( travel4 ,! dirigible balloon1 z x n[ exi/s aft] its developm5t dur+ ! w>1 is1 x is true1 n subject to ! %ortcom+s j m5tion$4 ,inde$1 9 _m ways x is p]haps sup]ior to ! airplane = photographic purposes1 s9ce x af=ds m space = cam]a & accessories1 & is fre] f vibration4 ,x is capable also ( mu* sl[] motion1 & c travel ) less dang] ov] =e/s & inaccessible areas :]e eng9e failure w\ld =ce a plane d[n to probable disa/]4 ,b ! small] types z at pres5t built are n design$ to fly s high z ! airplane1 & ! dirigibles1 bo? l>ge & small1 are f> m exp5sive 9 space & ma9t5ance ?an ! plane4 ,= ?is "o reason especially !y are n likely to be ! mo/ us$ cam]a c>ri]s ( ! a]ial photograph] ( ! future4 ,inasmu* z ! photographic problems ( ! plane are m difficult ?an ^? ( ! dirigible & at ! same "t broad]1 ! subject matt] ( ?is book applies ) equal =ce to photographic proc$ure = dirigibles4 ,developm5t ( ,airplane ,photography 9 ! ,great ,w>4--,! airplane has totally *ang$ ! nature ( w>f>e4 ,x has almo/ elim9at$ ! elem5t ( surprise1 by r5d]+ impossible t secrecy :i* =m]ly protect$ ! accumulation ( /ores1 or ! ga!r+ ( =ces = ! attack1 a flank+ movem5t or a 8/rategic retreat40 ,to ! side hav+ comm& ( ! air ! plans & activities ( ! enemy are an op5 book4 ,x is true t m is he>d ( combats betwe5 planes ?an ( ! r\t9e task ( collect+ in=mation1 & ! public m9d is m apt to be impress$ by ! fight+ & bomb+ aspects ( a]ial w>f>e4 ,nev]!less1 ! fact rema9s t ! *ief use ( ! airplane 9 w> is reconnaissance4 ,! airplane is 8! eye ( ! army40 ,9 ! e>ly days ( ! w>1 obs]vation 0 visual4 ,x 0 ! task ( ! obs]v] 9 ! plane to sket* ! outl9es ( tr5*es1 to c\nt ! vehicles 9 a transport tra91 to e/imate ! numb]s ( m>*+ m51 to record ! guns 9 an artill]y emplacem5t & to =m an idea ( _! size4 ,b ! capacity ( ! eye = includ+ & /udy+ all ! objects 9 a l>ge area1 p>ticul>ly :5 mov+ at high spe$1 0 soon f\nd to be q too small to prop]ly utilize ! "t & opportunities available 9 ! air4 ,moreov]1 ! con/ant wat*+ ( ! sky = ! 8,hun 9 ! sun0 di/ract$ ! obs]v] "t & "t aga9 f att5tion to ! e>? bel[4 ,v e>ly 9 ! w>1 !re=e1 m5's m9ds turn$ to photography4 ,! all-see+ & record+ eye ( ! cam]a took ! place ( ! obs]v] 9 e k9d ( "w except artill]y fire control & simil> problems :i* require imm$iate communication betwe5 plane & e>?4 ,! volume ( "w done by ! photographic sections ( ! milit>y air s]vice /eadily increas$ until t[>d ! end ( ! w> x became truly enorm\s4 ,! a]ial negatives made p] mon? 9 ! ,briti% s]vice alone m\nt$ into ! scores ( ?\s&s1 & ! pr9ts di/ribut$ 9 ! same p]iod numb]$ 9 ! neighborhood ( a million4 ,! task ( int]pret+ a]ial photographs became a highly specializ$ /udy4 ,an entirely new activity--t ( mak+ photographic mosaic maps & ( ma9ta9+ !m correct f day to day--usurp$ fir/ place among topographic problems4 ,by ! close ( ! w> sc>cely a s+le milit>y op]ation 0 und]tak5 )\t ! prelim9>y ( a]ial photographic in=mation4 ,photography 0 dep5d$ on to discov] ! objectives = artill]y & bomb+1 & to record ! results ( ! subsequ5t 8%oots0 & bomb explosions4 ,! exact configurations ( front1 second1 ?ird l9e & communicat+ tr5*es1 ! ma*9e gun & mort> positions1 ! 8pill boxes10 ! organiz$ %ell holes1 ! li/5+ po/s1 & ! b>b$ wire1 7 all reveal$1 /udi$ & attack$ entirely on ! evid5ce ( ! airplane cam]a4 ,t[>d ! end ( ! w> important troop movem5ts 7 possible only "u ! cov] ( d>kness1 :ile ! developm5t ( high int5sity fla%lights ?reat5$ to expose ev5 ^! to pitiless publicity4 ,limitations to ,airplane ,photography ,set by ,w> ,conditions4--,! ability ( ! pilot to take ! mod]n high-p[]$ plane ov] any *os5 po9t at any desir$ altitude 9 almo/ any condition ( w9d or wea!r gives to ! plane an ess5tial advantage ov] ! photographic kites & balloons ( pre-w> days4 ,!re are1 h[ev]1 c]ta9 disadvantages 9 ! use ( ! plane :i* mu/ be ov]come 9 ! design ( ! photographic app>atus & 9 ! me?od ( its use4 ,"s few ( ^! disadvantages are inh]5t 9 ! plane itself2 = in/ance1 ! necessity = high spe$ 9 ord] to rema9 9 ! air1 & ! vibration due to ! con/antly runn+ eng9e4 ,o!rs are peculi> to w> conditions1 & _! elim9ation 9 planes = peace-"t photography w give great opportunities = ! developm5t ( a]ial photography z a sci5ce4 ,*ief among ! w>-"t limitations is t ( economy ( space & weight4 ,a w> plane mu/ c>ry a c]ta9 equipm5t ( guns1 radio-telegraphic app>atus & o!r in/rum5ts1 all ( :i* mu/ be readily accessible4 ,_m planes h duplicate controls 9 ! re> cockpit to enable ! obs]v] to br+ ! plane to e>? 9 case ( accid5t to ! pilot4 ,armam5t & controls dem& space :i* mu/ be subtract$ f qu>t]s already cramp$1 s t 9 mo/ designs ( planes ! photographic outfit mu/ be accommodat$ 9 locations & spaces wret*$ly inadequate = x4 ,economy 9 weight is pu%$ to ! la/ extreme1 = e ounce sav$ means increas$ ceil+ & radius ( action1 a great] bomb+ load1 m ammunition1 or fuel = a long] flight4 ,h5ce comes ! con/ant pressure to limit ! weight ( photographic & o!r app>atus1 ev5 ?\gh ! tasks requir$ ( ! cam]a con/antly call = l>g] r ?an small] equipm5t4 ,to ano!r milit>y necessity is due 9 great measure ! =c$ developm5t ( a]ial photographic app>atus 9 ! direction ( automatic op]ation4 ,! practice ( entru/+ ! actual tak+ ( ! pictures to obs]v]s ) no photographic k1 ^: function 0 m]ely to 8press ! button0 at ! prop] "t1 necessitat$ cam]as z simple 9 op]ation z possible4 ,! multiplicity ( tasks assign$ to ! obs]v]1 & 9 p>ticul> ! ev] vital "o ( wat*+ = enemy aircraft1 made ! developm5t ( l>gely or :olly automatic cam]as ! w>-"t ideal ( all a]ial photographic s]vices4 ,:e!r ! free+ ( ! obs]v] f o!r tasks w relegate ! necess>ily complex & exp5sive automatic cam]a to /rictly milit>y use rema9s to be se54 ,,*apt] ,,ii ,,! ,,airplane ,,consid]$ ,,z ,a ,,cam]a ,,plat=m ,an ess5tial "p ( ! equipm5t ( ei!r ! a]ial photograph] or ! design] ( a]ial photographic app>atus is a work+ k ( ! pr9ciples & con/ruction ( ! airplane1 & consid]able actual exp]i5ce 9 ! air4 ,conditions & requirem5ts 9 ! fly+ plane are f> diff]5t f ^? ( ! %op b5* or photographic /udio4 ,z a prelim9>y to und]tak+ any "w on airplane in/rum5ts a good text-book on ! pr9ciples ( flight %\ld be /udi$4 ,su* g5]al ideas z are necess>y = und]/&+ ! purely photographic problems are1 h[ev]1 outl9$ 9 ! next p>agraphs4 ,illu/ration3 ,,fig4 #a4--,! elem5ts ( ! plane4 ,con/ruction ( ! ,airplane4--,! mod]n airplane 7,fig4 #a7 consi/s ( "o or m planes1 mu* long] across ?an 9 ! direction ( flight 7aspect ratio74 ,^! are incl9$ slightly upw>d t[>d ! direction ( travel1 & _! rapid motion ?r\gh ! air1 due to ! pull ( ! propell] driv5 by ! motor1 causes !m to rise f ! e>?1 c>ry+ ! fuselage or body ( ! airplane4 ,9 ! fuselage are c>ri$ ! pilot1 obs]v]1 & any o!r load4 ,:eels bel[ ! fuselage =m+ ! "u-c>riage or l&+ ge> s]ve to support ! body :5 runn+ along ! gr\nd 9 tak+ (f or l&+4 ,! pilot1 sitt+ 9 "o ( ! cockpits1 has 9 front ( him ! controls1 by means ( :i* ! motion ( ! plane is guid$ 7,figs4 #b & #c74 ,^! consi/ ( ! eng9e controls--! contacts = ! ignition1 ! ?rottle1 ! oil & gasol9e supply1 air pressure1 etc41 & ! /e]+ controls--! rudd] b>1 ! /ick & ! /abiliz] control4 ,! rudd] b>1 op]at$ by ! feet1 controls bo? ! rudd] ( ! plane1 :i* turns ! plane to "r or left 9 ! air1 & ! tail skid1 = /e]+ on ! gr\nd4 ,! /ick is a v]tical column 9 front ( ! pilot :i*1 :5 pu%$ =w>d or back1 depresses or raises ! elevator & makes ! ma*9e dive or climb4 ,?r[n to ei!r side x op]ates ! ail]ons or w+ tips1 :i* cause ! plane to roll ab\t its =e & aft axis4 ,! /abiliz] control is usually a :eel at ! side ( ! cockpit1 ^: turn+ v>ies ! angle ( incid5ce ( ! small /abiliz+ plane 9 front ( ! elevator1 to correct ! balance ( ! plane "u diff]5t conditions ( load+4 ,illu/ration3 ,,fig4 #b4--;,=w>d cockpit ( ,de,haviland #d1 %[+ in/rum5t bo>d4 ,illu/ration3 ,,fig4 #c4--,re> cockpit ( ,de,haviland #d1 %[+ re> 8/ick0 & rudd] b>4 ,! fuselage consi/s usually ( a light holl[ framework ( spruce or a%1 divid$ into a s]ies ( bays or comp>tm5ts by upright memb]s1 connect+ ! long]ons1 :i* are ! f\r corn] memb]s1 runn+ =e & aft1 ( ! plane4 ,diagonally across ! sides & faces ( ^! bays are /ret*$ taut piano wires1 & ! :ole /ructure is cov]$ ) canvas or l95 fabric4 ,cross-wires & fabric are omitt$ f ! top ( "o or m bays to p]mit _! be+ us$ z cockpits = pilot & obs]v]4 ,9 lat] designs ( planes ! wire & fabric con/ruction has be5 sup]s$$ by ply-wood v5e]1 !reby /r5g!n+ ! fuselage s t _m ( ! diagonal brac+ wires on ! inside are disp5s$ )4 ,?is greatly increases ! accessibility ( ! spaces 9 :i* cam]as & o!r app>atus mu/ be c>ri$4 ,illu/ration3 ,,fig4 #d4--;,biplane 9 flight4 ,! fuselage diff]s greatly 9 cross-section %ape & 9 room9ess accord+ to ! type ( eng9e4 ,9 ! majority ( ,engli% & ,am]ican planes1 ) _! v]tical cyl9d] or ,v type eng9es1 ! fuselage is n>r[ & rectangul> 9 cross-section4 ,9 _m ,fr5* planes1 radial or rot>y eng9es are us$ & ! fuselage is correspond+ly almo/ circul>1 & s is mu* m spaci\s ?an ! ,engli% & ,am]ican planes ( simil> p[]4 ,! %ape & size ( ! plane body has an important be>+ on ! "q ( cam]a in/allation4 ,illu/ration3 ,,fig4 #e4--;,a s+le-seat]4 ,types ( ,planes4--,! mo/ common type ( plane is ! biplane 7,fig4 #d71 ) its two planes1 connect$ by /ruts & wires1 set n directly ov] ea* o!r1 b /agg]$1 usually ) ! upp] plane lead+4 ,monoplanes 7 9 favor 9 ! e>ly days ( aviation1 & triplanes h be5 us$ to "s ext5t4 ,accord+ to ! position ( ! propell] planes are classifi$ z tractors or pu%]s1 tractors be+ at pres5t ! m common =m4 ,planes are fur!r classifi$ z s+le-seat]s 7,fig4 #e71 two-seat]s1 & ?ree-seat]s4 ,^! motor & pass5g] me?ods ( classification are n[ prov+ inadequate ) ! rapid developm5t ( planes c>ry+ two1 ?ree1 & ev5 m motors1 divid$ betwe5 pu%] & tractor op]ation1 & c>ry+ increas+ly l>ge numb]s ( pass5g]s4 ,aside f /ructure1 planes may be fur!r classifi$ accord+ to _! uses1 z sc\t1 combat1 reconnaissance1 bomb+1 etc4 ,planes equipp$ ) floats or pontoons = alight+ on ! wat] are call$ seaplanes 7,fig4 #ahb71 & ^? 9 :i* ! fuselage is boat-%ap$1 to p]mit ( float+ directly on ! wat]1 are fly+ boats 7,fig4 #ahc74 ,! ,plane 9 ! ,air4--,! fir/ flight ( ! photographic obs]v] or ( ! in/rum5t exp]t :o is to "w ^u airplane in/rum5ts is v pr(itably made z a 8joy ride10 to famili>ize him ) conditions 9 ! air4 ,8 exp]i5ce w be some:at z foll[s3 ,! plane is br\ght out ( ! hang>1 c>efully gone ov] by ! me*anics1 & ! eng9e 8w>m$ up40 ,! pilot m9utely inspects all p>ts ( ! 8%ip10 !n climbs up into ! front cockpit4 ,he we>s helmet & goggles1 & if ! wea!r is cold or if he expects to fly high1 a heavy wool-l9$ coat or suit1 ) ?ick gloves & moccas9s1 or an electrically heat$ suit4 ,! pass5g]1 likewise attir$1 climbs into ! re> cockpit & /raps himself into ! seat4 ,he f9ds himself sitt+ r l[ d[n1 ) ! sides ( ! cockpit ne>ly on a level ) 8 eyes4 ,to ei!r side ( 8 knees & feet are taut wires lead+ f ! controls to ! elevator1 /abiliz]1 tail skid & rudd]4 ,if ! ma*9e is dual control1 ! /ick is betwe5 8 knees1 ! rudd] b> be=e 8 feet4 ,none ( ^! mu/ he let 8 body t\*1 s 9 ! ord9>y two-seat] 8 qu>t]s are badly cramp$4 ,at ! ^w 8contact0 ! me*anics sw+ ! propell]1 &1 sometimes only aft] sev]al trials1 ! motor />ts1 ) a ro> & a ru% ( w9d 9 ! pass5g]'s face4 ,aft] a mom5t's sl[ runn+ x is spe$$ up1 ! int]mitt5t ro> becomes a cont9u\s note1 ! plane %akes & /ra9s1 :ile ! me*anics hold d[n ! tail to prev5t a premature take-(f4 ,:5 ! eng9e is prop]ly w>m$ up x is ?rottl$ to a l[ spe$1 ! *ocks "u ! :eels are remov$1 ! me*anics hold "o end ( ! l[] w+ s t ! plane sw+s ar\nd t[>d ! field4 ,x !n 8taxis0 out to a favorable position fac+ into ! w9d ) a cle> /ret* ( field be=e x4 ,aft] a c>eful look ar\nd to see t no o!r planes are l&+1 tak+ (f1 or 9 ! air ne> by1 ! pilot op5s out ! eng9e1 ! ro> increases its pit*1 ! plane moves sl[ly along ! gr\nd1 ga!rs spe$ & rises smoo?ly into ! air4 ,ne> ! gr\nd ! air is apt to be 8bumpy10 ! plane may drop or rise abruptly1 or tilt to ei!r side4 ,! pilot in/antly corrects ^! deviations1 & ! plane cont9ues to climb until /eadi] air is rea*$4 ,at fir/ ! pass5g]'s *ief impressions are apt to be ! deaf5+ noise ( ! motor1 ! heavy vibration1 ! t]rific w9d 9 8 face4 ,if he raises 8 h& above ! edge ( ! cockpit he realizes ! magnitude ( w9d resi/ance at ! spe$ ( ! plane1 & h5ce ! importance ( ! /ream-l9e section ( all /ruts & project+ p>ts4 ,:5 he rea*es ! desir$ altitude ! pilot levels (f ! plane & ceases to climb4 ,n[ 8 task is to ma9ta9 ! plane on an ev5 keel by means ( ! controls1 correct+ z soon z he notes x1 any t5d5cy to 8pit*10 to 8roll0 or to 8yaw0 (f ! c\rse4 ,! resultant pa? is "o :i* approximates to level /raight fly+ to a degree condition$ by ! /ead9ess ( ! air & ! skill ( ! pilot4 ,if he is n skilful or quick 9 8 reactions he may keep ! plane on its level c\rse only by alt]nately climb+ & glid+1 by fly+ ) fir/ "o w+ d[n & !n ! o!r1 by po9t+ to ! "r & !n to ! left4 ,! skill$ photographic pilot w hold a plane level 9 bo? directions to )9 a few degrees1 b he w d ?is easily only if ! plane is prop]ly balanc$4 ,if ! load on ! plane is su* z to move ! c5t] ( gravity too f> =w>d ) respect to ! c5t] ( lift ! plane w be nose-heavy1 if ! load is too f> back x w be tail-heavy4 ,ei!r ( ^! conditions c be correct$1 at "s co/ 9 effici5cy1 by *ang+ ! incl9ation ( ! /abiliz]4 ,:5 ! plane rea*es high altitudes 9 r>e air1 :]e x c g no fur!r1 x is said to h rea*$ its ceil+4 ,x "h travels level only by po9t+ its w+s upw>d 9 ! climb+ position1 s t ! fuselage is no long] p>allel to ! direction ( flight4 ,an und]/&+ ( ^! peculi>ities ( ! plane 9 flight is ( prime importance 9 photographic map mak+1 :]e ! cam]a %\ld be accurately v]tical at all times4 ,! direction & velocity ( ! w9d mu/ be c>efully consid]$ by ! pilot 9 mak+ any pr$et]m9$ c\rse or objective4 ,! progress ( ! plane due to ! pull ( ! propell] is prim>ily ) ref]5ce to ! air4 ,if ?is is 9 motion ! plane's gr\nd spe$ & direction w be alt]$ accord+ly4 ,9 fly+ ) or aga9/ ! w9d ! gr\nd spe$ is ! sum or diff]5ce1 respectively1 ( ! plane's air spe$ 7det]m9$ by an air spe$ indicator7 & ! spe$ ( ! w9d4 ,if ! pr$et]m9$ c\rse lies m or less across ! w9d ! plane mu/ be po9t$ into ! w9d1 9 :i* case its travel1 ) respect to ! e>?1 is n 9 ! l9e ( its =e & aft axis4 ,! effect ( 8crabb+10 z x is call$1 on photographic calculations is discuss$ lat] 7,figs4 #acf & #ach74 ,:5 ! plane has rea*$ ! end ( its /raight c\rse & />ts to turn1 its level position is = ! mom5t entirely giv5 up 9 ! op]ation ( bank+ 7,fig4 #f74 ,j z ! tracks on ! curve ( a railroad are rais$ on ! out] side to oppose ! t5d5cy ( ! tra9 to slip outw>d1 s ! plane mu/ be tilt$1 by means ( ! ail]ons1 t[>d ! inside ( ! turn4 ,a po9t to be cle>ly kept 9 m9d ab\t a bank is t if correctly made a plumb l9e inside ! fuselage w cont9ue to hang v]tical ) respect to ! floor ( ! plane1 & n ) respect to ! e>?1 = ! =ce act+ on x is ! comb9ation ( gravity & ! accel]ation outw>d due to ! turn4 ,only "s =m ( gyroscopically controll$ po9t]1 keep+ its direction 9 space1 w indicate ! incl9ation ( ! plane ) respect to ! true v]tical4 ,if ! bank+ is insuffici5t ! plane w side slip outw>d or skid2 if too great1 x w side slip inw>d4 ,illu/ration3 ,,fig4 #f4--;,bank+4 ,z "p ( ! 8joy ride0 ! pilot may d a few 8/unts10 su* z a 8/all10 a 8loop10 a 8tail sp910 or an 8,immelman40 ,f ! photographic /&po9t ^! are ( int]e/ 9 s f> z !y be> on ! "q ( hold+ ! cam]a 9 place 9 ! plane4 ,! ?+ to be not$ "h is t 7p>ticul>ly 9 ! loop71 if ^! maneuv]s are prop]ly p]=m$1 !re is little t5d5cy t[>d relative motion betwe5 plane & app>atus4 ,9 a p]fect loop x w\ld1 = in/ance1 be unnecess>y1 due to ! c5trifugal =ce outw>d1 = ! obs]v] to /rap himself 94 ,x is1 h[ev]1 unwise to place implicit confid5ce 9 ! p]fection ( ! pilot's a]ial gymna/ics4 ,no app>atus %\ld be left entirely free1 al?\gh1 = ! reason giv51 comp>atively light fa/5+s are usually suffici5t4 ,:5 ne>+ ! l&+ field ! pilot w ?rottle d[n ! eng9e & comm5ce to glide4 ,if he is at a consid]able altitude he may come d[n a l>ge "p ( ! di/ance 9 a rapid spiral4 ,z ! e>? is approa*$ ! air pressure increases rapidly1 & ! pass5g]1 if correctly in/ruct$1 w op5 8 m\? & swall[ frequ5tly to equalize ! air pressure on 8 e> drums4 ,j be=e ! gr\nd is rea*$ ! plane is level$ (f1 x loses spe$1 &1 if ! l&+ is p]fect1 t\*es & runs along ! gr\nd )\t b\nc+ or bump+4 ,frequ5tly1 h[ev]1 ! impact ( ! tail is suffici5tly h>d to cause x to bump badly1 ) a consequ5t consid]able dang] to app>atus ( any weight or delicacy4 ,?is is especially apt to occur 9 ha/ily *os5 & poorly level$ fields su* z mu/ (t5 be utiliz$ 9 w> or 9 cross-c\ntry fly+4 ,appe>ance ( ! ,e>? f ! ,plane4--,! view f ! ord9>y two-seat] is greatly re/rict$ by ! eng9e 9 front & by ! planes to ei!r side & bel[ 7,figs4 #g1 #h1 & #i74 ,by cran+ 8 neck ov] ! side1 or by look+ d[n ?r\gh an op5+ 9 ! floor1 ! pass5g] has an opportunity to le>n ! g5]al appe>ance ( ! subject he is lat] to devote 8 att5tion to photograph+4 ,p]haps ! mo/ /rik+ impression he receives w be t ( ! flatness ( ! e>?1 bo? 9 ! s5se ( abs5ce ( relief & 9 ! s5se ( abs5ce ( extremes ( light & %ade4 ,! abs5ce ( relief is due to ! fact t at ord9>y fly+ heights ! elevations ( natural objects are too small = ! natural sep>ation ( ! eyes to give any /]eoscopic effect4 ,! abs5ce ( extremes ( light & %ade is 9 "p due to ! fact t ! natural surfaces ( e>?1 grass & =e/ pres5t no great range ( brightness2 9 "p to ! small relative areas ( ! p>ts 9 %ad[2 9 consid]able "p to ! lay] ( atmosph]ic haze :i* lies z an illum9at$ veil betwe5 ! obs]v] & ! e>? at altitudes ( #bjjj met]s & ov] 7,figs4 #aj & #aa74 ,due to ! comb9ation ( ^! factors ! e>? bel[ pres5ts ! appe>ance ( a delicate pa/el4 ,z ! gaze is direct$ away f ! t]ritory directly bel[1 ! ?ickness ( atmosph]e to be pi]c$ rapidly increases1 until t[>d ! horizon 7:i* lies level ) ! obs]v] "h z on ! gr\nd7 all detail is apt to be oblit]at$ to su* an ext5t t only on v cle> days c ! horizon itself be def9itely f\nd or be di/+ui%$ f l[ ly+ haze or cl\ds 7,fig4 #d74 ,illu/ration3 ,,fig4 #g4--,! view ahead4 ,illu/ration3 ,,fig4 #h4--,! view a/]n4 ,airplane ,in/rum5ts4--,m\nt$ on bo>ds 9 front ( ! pilot & obs]v] are v>i\s in/rum5ts to indicate ! p]=mance ( eng9e & plane 7,fig4 #b74 ,^? ( int]e/ to ! photographic obs]v] are ! compass1 ! altimet]1 ! air spe$ indicator1 ! incl9omet]s4 ,illu/ration3 ,,fig4 #i4--,! view betwe5 ! w+s4 ,illu/ration3 ,,fig4 #aj4--;,appe>ance ( ! e>? f a l[ altitude--#cjjj feet or less4 ,! compass is usually a special airplane compass1 ) its 8c>d0 imm]s$ 9 a damp+ liquid4 ,l mo/ ( ! direction indicat+ in/rum5ts on a plane its indications are only ( significance :5 ! plane is pursu+ a /eady c\rse4 ,on turns or rapid *anges ( direction ( any sort p]turbations prev5t accurate read+4 ,! altimet] is ( ! common an]oid b>omet] type4 ,on ,am]ican in/rum5ts x is usually graduat$ to read 9 #ajj-;foot /eps4 ,:ile some:at sluggi%1 x is q satisfactory = all ord9>y det]m9ations ( altitude 9 photographic "w4 ,7 prim>y map mak+ to be und]tak51 :]e ! scale 0 det]m9able only f ! altitude & focal l5g? ( ! l5s1 ! ord9>y altimet] is h>dly accurate en\gh4 ,illu/ration3 ,,fig4 #aa4--;,appe>ance ( ! e>? f a high altitude--#aj1jjj feet or m4 ,! air spe$ indicator consi/s ( a comb9ation ( ,v5turi & ,pitot tubes1 produc+ a diff]5ce ( pressure :5 9 motion ?r\gh ! air :i* is measur$ on a scale calibrat$ 9 air spe$4 ,?is in/rum5t is important = det]m9+1 9 comb9ation ) w9d spe$1 ! gr\nd spe$ ( ! plane1 on ! basis ( :i* is calculat$ ! int]val betwe5 exposures to secure ov]lapp+ photographs4 ,its accuracy is well above t necess>y = ! purpose4 ,incl9omet]s = %[+ ! lat]al & =e & aft angle ( ! plane ) ! horizontal1 are occasionally us$1 & h also be5 incorporat$ 9 cam]as4 ,! important po9t to rememb] ab\t ^! in/rum5ts is t !y are controll$ n alone by gravity b z well by ! accel]ation ( ! plane 9 any direction4 ,!y consequ5tly indicate correctly only :5 ! plane is fly+ /raight4 ,on a bank ! lat]al indicator cont9ues to indicate 8v]tical0 if ! bank is prop]ly calculat$ = ! turn4 ,,ii ,,! ,,airplane ,,cam]a ,,*apt] ,,iii ,,! ,,cam]a--,,g5]al ,,consid]ations ,*ief ,uses ( an ,airplane ,cam]a4--,! k9ds ( cam]a suitable = airplane use & ! mann] 9 :i* !y mu/ diff] f cam]as = use on ! gr\nd are det]m9$ by consid]ation ( ! nature ( ! "w !y mu/ d4 ,f\r k9ds ( pictures con/itute ! ord9>y dem&s ^u ! a]ial photograph]4 ,^! are s+le objectives or p9 po9ts1 mosaic maps ( /rips ( t]ritory or l>ge areas1 oblique views1 & /]eoscopic views4 ,ea* ( ^! pres5ts its own peculi> problems influ5c+ cam]a design4 ,p9po9ts consi/ ( su* objects z gun emplacem5ts1 railway /ations1 ammunition dumps1 & o!r objects ( :i* photographs ( consid]able magnification are desir$ = /udy4 ,"h ! in/rum5tal requirem5ts are suffici5t focal l5g? ( l5s to secure an image ( adequate size2 means = po9t+ ! cam]a accurately2 en\gh %utt] spe$ to c\nt]balance ! spe$ ( ! plane2 suffici5tly wide l5s ap]ture to give adequate exposure ) ! %utt] spe$ requir$2 means ( support+ ! cam]a to protect x f ! vibration ( ! plane4 ,mosaic maps are built up f a l>ge numb] ( photographs ( adjac5t areas4 ,9 addition to ! above requirem5ts1 mosaic maps dem& l5ses free f di/ortion & cov]+ z l>ge a plate z possible1 9 ord] to keep to a m9imum ! numb] ( pictures ne$$ to cov] a giv5 area2 means = keep+ ! cam]a accurately v]tical1 & means = *ang+ ! plates or films & resett+ ! %utt] rapidly en\gh to avoid gaps betwe5 successive pictures4 ,at l[ altitudes & high gr\nd spe$s ! int]val betwe5 exposures becomes a matt] ( only a few seconds4 ,oblique views are made at angles ( f #ab to #ce degrees f ! horizontal1 usually f comp>atively l[ altitudes4 ,!y h be5 f\nd to be p>ticul>ly suitable = ! use ( m5 :o h no tra9+ 9 photographic int]pretation1 be+ m l ! pictures ) :i* ! m5 are famili>4 ,di/ribut$ among ! infantry be=e an attack1 !y h prov$ indisp5sable aids to ! prop] k ( ! gr\nd to be cov]$4 ,! additional requirem5t "h is = high %utt] spe$ to elim9ate ! effect ( ! relatively v rapid movem5t ( ! =egr\nd4 ,/]eoscopic views are among ! mo/ useful ( all airplane pictures4 ,!y are made f successive exposures1 ! sep>ation ( ! po9ts ( view be+ obta9$ n by two l5ses at ! di/ance ( ! eyes ap>t1 b by ! motion ( ! plane4 ,= ?is purpose ! views %\ld ov]lap by at lea/ #fj p] c5t2 ?is1 !re=e1 requires a v %ort int]val betwe5 exposures4 ,= /]eo-oblique views ?is may mean t !y are tak5 at int]vals z %ort z "o or two seconds4 ,*ief ,diff]5ces betwe5 ,gr\nd & ,air ,cam]as4--,c]ta9 def9ite diff]5ces are ?us se5 to /& out betwe5 airplane cam]as & ! ord9>y k9d4 ,x is ess5tial t ! app>atus = use 9 ! air %all h high l5s & %utt] spe$1 means = rapid *ang+ ( plates1 & anti-vibration susp5sion4 ,)\t ^! features a cam]a is ( little use = a]ial "w4 ,^! requirem5ts lead inevitably to great] complexity ( design4 ,"o simplification ov] gr\nd cam]as1 h[ev]1 is br\ght ab\t by ! fact t all exposures are made on objects beyond ! practical inf9ity po9t ( ! l5s2 consequ5tly1 all cam]as are fix$ focus4 ,?is fix$ focus feature is a positive advantage 9 con/ruction1 s9ce x p]mits ( ! simple rigid box =m1 desirable & necess>y to )/& ! /ra9s due to ! weight ( ! l5s & ! /resses f ! plane4 ,b ) ! ab&onm5t ( all provision = focuss+ 9 ! air mu/ g special c>e t ! mat]ial us$ 9 con/ruct+ ! cam]a body is z little subject z possible to expansion & contraction ) temp]ature1 s9ce !re is (t5 a drop ( #cj to #dj degrees ,c5tigrade f gr\nd to upp] air4 ,! effect ( *ange ( temp]ature on focus w be treat$ 9 ! discussion ( l5ses4 ,9 addition to ^! diff]5ces1 we mu/ keep 9 m9d c]ta9 requirem5ts :i* are condition$ by ! nature & place ( a]ial navigation4 ,?us all me*anical devices :i* w fail to function at ! l[ temp]atures & pressures met at high altitudes are entirely unsuitable4 ,exp]i5ce has %[n1 too1 t we mu/ avoid all me*anism dep5d+ prim>ily on spr+s & on ! action ( gravity4 ,vibration1 & ! motion ( ! plane 9 all ?ree dim5sions1 conspire to r5d] me*anical motions unreliable :5 actuat$ by ^! ag5cies4 ,all plate *ang+1 %utt] sett+1 & expos+ op]ations %\ld be z ne>ly z possible positively controll$ motions4 ,because ( ! cold ( ! upp] air all knobs1 lev]s & cat*es mu/ be made extra l>ge & easy to h&le ) heavy gloves4 ,circul> knurl$ heads to su* p>ts z %utt] sett+ movem5ts are to be avoid$ 9 favor ( bat-w+ keys or lev]s4 ,grooves = ! reception ( magaz9es mu/ be z l>ge & smoo? z possible1 & guides to facilitate ! magaz9es' introduction %\ld be provid$ 7,fig4 #ej74 ,no releases or adju/m5ts :i* dep5d ^u he>+ or ^u a delicate s5se ( t\* are feasible 9 airplane app>atus4 ,:]ev] possible1 l>ge visible indicators ( ! /age ( ! cycle ( op]ations %\ld be provid$4 ,loose p>ts are to be %unn$1 z !y are inv>iably lo/ 9 s]vice4 ,complete op]at+ in/ructions %\ld be plac$ on ! app>atus :]ev] possible1 to m9imize ! confusion due to *ang+ & un9/ruct$ p]sonnel4 ,! ,elem5ts ( ! ,airplane ,cam]a4--,disreg>d+ its means ( susp5sion1 ! airplane cam]a prop] consi/s ess5tially ( l5s1 cam]a body1 %utt]1 & plate or film hold+ & *ang+ box4 ,9 c]ta9 ( ! a]ial cam]as develop$ e>ly 9 ! w> all ( ^! elem5ts 7 built toge!r 9 a common enclosure4 ,lat] x 0 g5]ally recogniz$ t a unit sy/em ( int]*angeable p>ts is pref]able4 ,9 ! case ( ! l5s !re arose v>i\s requirem5ts = focal l5g?1 f #be to #abj c5timet]s1 accord+ to ! "w to be done4 ,r ?an use an entirely diff]5t cam]a = ea* diff]5t k9d ( "w1 x is bett] to h l5ses ( v>i\s focal l5g?s1 m\nt$ 9 tubes or cones1 all built to atta* to ! same cam]a body4 ,9 ! case ( ! %utt] x is desirable to be able to repair or calibrate p]iodically4 ,by mak+ ! %utt] a removable unit1 ! provision ( a few sp>es does away ) ! ne$ = putt+ ! :ole cam]a out ( commission4 ,simil> consid]ations hold ) ref]5ce to o!r p>ts4 ,a fur!r mat]ial advantage t comes f mak+ airplane cam]as 9 sections is ! great] ease ) :i* !y are ins]t$ 9 ! plane1 usually ?r\gh ! op5+s betwe5 diagonal cross-wires4 ,x is 9 fact only by virtue ( ?is possibility ( break+ up into small elem5ts t "s ( ! l>g] cam]as c\ld be ins]t$ 9 ! common types ( reconnaissance plane4 ,illu/rations ( ! build+ up ( cam]as f sep>ate removable elem5ts are giv5 9 ! detail$ discussion ( ! individual types4 ,types ( ,airplane ,cam]as4--,dur+ ! c\rse ( ! w> airplane cam]as h be5 classifi$ on v>i\s bases1 9 diff]5t s]vices4 ,9 ! ,fr5* s]vice1 :]e ! de,maria type ( cam]a 0 /&>diz$ e>ly 9 ! w>1 ! usual classification 0 bas$ on focal l5g?2 ?us ! /&>d cam]as 7 spok5 ( z ! #bf1 ! #ej & ! #abj 7c5timet]74 ,a fur!r di/9ction 0 !n made accord+ to ! size ( plate1 ?is be+ orig9ally #ac #ah c5timet]s = ! #bf c5timet]1 & #ah #bd c5timet]s = ! l>g] cam]as4 ,9 ! ,engli% s]vice ! #d #e in* plate 0 us$ almo/ exclusively1 & _! v>i\s types ( cam]as 7 kn[n by s]ial lett]s--,c1 ,e1 ,l1 etc4 ,bo? ^! modes ( classification became inadequate ) ! ultimate agreem5t to /&>dize on ! #ah #bd c5timet] size = all plates1 & to c>ry l5ses ( all focal l5g?s 9 int]*angeable elem5ts4 ,= purposes ( description & discussion1 x is mo/ conv5i5t to classify cam]as accord+ to _! me?od ( op]ation & ! s5sitive mat]ial employ$4 ,on ?is basis we may di/+ui% among cam]as us+ plates ?ree k9ds--non-automatic cam]as1 semi-automatic cam]as1 & automatic cam]as4 ,we may simil>ly discuss film cam]as1 b hav+ treat$ ! plate cam]as compreh5sively1 x w be f\nd t ! discussion ( all types ( film cam]a c be h&l$ mo/ conv5i5tly by /udy+ ! diff]5ces 9 con/ruction & op]ation introduc$ by ! *>act]i/ics ( film z comp>$ to plates4 ,,*apt] ,,iv ,,l5ses ,,= ,,a]ial ,,photography ,g5]al ,consid]ations4--,! design & selection ( l5ses = a]ial photography pres5t on ! :ole no problems n already enc\nt]$ 9 photography ( ! m famili> sort4 ,inde$1 ! l5s problem 9 ! airplane cam]a is 9 "s p>ticul>s m simple ?an 9 ! gr\nd cam]a4 ,= in/ance1 !re is no dem& = dep? ( focus--all objects photograph$ are well beyond ! usually assum$ 8inf9ity focus0 ( #bjjj times ! l5s diamet]4 ,su* /rictly sci5tific problems ( design z p]ta9 to a]ial photographic l5ses are ones ( degree r ?an ( k9d4 ,l>g] ap]ture1 great] cov]+ p[]1 small] di/ortion1 m exquisite def9ition--^! always w be 9 dem&1 & ea* progressive improvem5t w be reflect$ 9 advances 9 ! art ( a]ial photography4 ,b _m l5s designs p]fect$ be=e ! w> 7 admirably suit$1 )\t any *ange at all1 = a]ial cam]as4 ,( ! utmo/ s]i\sness1 h[ev]1 ) ! ,allies1 0 ! problem ( secur+ l5ses ( ! desir$ types 9 suffici5t numb]s4 ,! manufacture ( ! _m v>ieties ( optical glass ess5tial to mod]n photographic l5ses 0 almo/ exclusively a ,g]man indu/ry1 :i* _h to be le>n$ & inaugurat$ 9 ,alli$ c\ntries s9ce #aiad4 ,9 consequ5ce ( ?is entirely practical problem ( quantity production )\t ! glasses = :i* l5s =mul 7 at h&1 "s new l5s designs 7 produc$4 ,:e!r any ( ^! possess m]its :i* w lead !m to be pref]r$ ov] pre-w> designs1 :5 ! latt] c aga9 be manufactur$1 rema9s to be se54 ,:ile ! glass problem 0 /ill unsolv$1 a]ial cam]as _h to be equipp$ ) :atev] l5ses c\ld be secur$ by requisition f pre-w> importation & manufacture1 & lat]1 ) l5ses design$ to utilize ^? glasses ^: manufacture _h be5 ma/]$ 9 ! alli$ c\ntries4 ,x is important t ! hi/orical aspect ( ?is matt] be well und]/ood by ! /ud5t ( a]ial photographic me?ods1 = ! use ( ^! odd-lot l5ses react$ on ! :ole design ( a]ial cam]as & on ! me?ods ( a]ial photography1 p>ticul>ly 9 ,engl& & ! ,unit$ ,/ates4 ,almo/ )\t exception ! available l5ses 7 ( %ort focus1 consid]$ f ! a]ial photographic /&po9t2 t is1 !y lay betwe5 eight & twelve in*es4 ,?is set a limit to ! size ( ! airplane cam]a1 q irrespective ( ! dem&s made by ! nature ( ! photographic problem4 ,l5ses ( ^! focal l5g?s produc$ images :i*1 = ! usual heights ( fly+1 7 g5]ally consid]$ too small1 & :i* 71 !re=e1 almo/ always subsequ5tly enl>g$4 ,su* 0 ! ,engli% practice1 :i* 0 foll[$ 9 ! tra9+ ( a]ial photograph]s 9 ,am]ica1 :]e exactly simil> conditions held at ! />t ) respect to available l5ses4 ,fr5* glass & l5s manufactur]s did succe$ 9 supply+ l5ses ( long] focus 7#ej c5timet]s71 9 numb]s suffici5t = _! own s]vice1 al?\gh nev] ) any c]ta9ty = _! allies4 ,! ,fr5*1 !re=e1 almo/ f ! />t1 built _! cam]as ) l5ses ( long focus1 & made contact pr9ts f _! negatives4 ,practices adopt$ "u pressure ( an em]g5cy to meet tempor>y practical limitations (t5 come to dom9ate ! :ole situation4 ,?is is p>ticul>ly true ( a]ial photography 9 ! ,briti% & ,am]ican s]vices4 ,! small app>atus built ar\nd ! /op-gap %ort focus l5ses fix$ ! plane design]'s idea ( an airplane cam]a1 & ! space x %\ld occupy4 ,?is 0 directly reflect$ 9 ! designs ( ! ,engli% planes1 & ! ,am]ican planes copi$ aft] !m4 ,mean:ile ! ,am]ican photographic s]vice 9 ,france associat$ itself ) ! ,fr5* s]vice1 adopt+ its me?ods & app>atus1 & us+ ,fr5* planes ^: designs 7 n be+ foll[$ 9 ,am]ican con/ruction4 ,! task ( h>moniz+ ! photographic practice z taught 9 ,am]ica1 foll[+ ,engli% l9es1 ) ,fr5* practice z foll[$ 9 ! !at] ( w>1 & ( adapt+ planes built on ,engli% designs s t !y c\ld c>ry ,fr5* app>atus1 0 a =midable "o1 n likely to be soon =gott5 by any :o _h a "p 9 x4 ,photographic ,l5s ,*>act]i/ics4--,:ole volumes h be5 writt5 on ! photographic l5s1 & on ! optical sci5ce utiliz$ & inde$ br\ght into be+ by its problems4 ,su* works %\ld be consult$ by ^? :o int5d to make a s]i\s /udy ( ! design ( l5ses = a]ial use4 ,no m c be attempt$1 no m inde$ is relevant "h1 ?an an outl9e review ( ! *ief *>act]i/ics & errors ( photographic l5ses1 consid]+ !m ) special ref]5ce to a]ial ne$s4 ,! mod]n photographic l5s is1 broadly speak+1 a developm5t ( ! simple convex or conv]g+ l5s4 ,its function is ! same3 to =m a real image ( objects plac$ be=e x4 ,b ! diff]5ce 9 p]=mance betwe5 ! simple l5s & ! mod]n photographic objective is enorm\s4 ,! simple l5s =ms a cle> image only close to its axis1 = light ( a s+le color1 & z long z its ap]ture is kept q small z comp>$ to ! di/ance at :i* ! image is =m$4 ,! photographic l5s1 on ! o!r h&1 is call$ ^u to produce a cle> image ) light ( a wide range ( spectral composition1 %>ply def9$ ov] a flat surface ( l>ge area1 & x mu/ d ?is ) an ap]ture t is l>ge 9 comp>ison ) ! focal l5g?1 :]eby ! am\nt ( light fall+ on ! image surface %all be a maximum4 ,?is ideal is approximat$ to a really extraord9>y degree by ! sci5tific comb9ation & arrangem5t ( l5s elem5ts made f special k9ds ( glass 9 ! be/ photographic l5ses ( ! ana/igmat type4 ,! result is ( necessity a set ( compromises1 :]eby ! out/&+ errors are r$uc$ to a size judg$ p]missible 9 view ( ! "w ! l5s is to d4 ,^! errors or ab]rations are briefly review$ bel[1 9 ord] t ! read] may readily grasp ! t]ms 9 :i* ! p]=mance & tol]ances 9 a]ial l5ses are describ$4 ,illu/ration3 ,,fig4 #ab4--;,diagrammatic repres5tation ( sph]ical ab]ration4 ,sph]ical ,ab]ration & ,coma4--,suppose we focus on a scre51 by means ( a simple convex l5s ! image ( a di/ant po9t ( light4 ,suppose = simplicity t ?is image is locat$ on ! axis ( ! l5s & t light ( only "o color is us$1 su* z yell[4 ,x w be f\nd t ! smalle/ image t c be obta9$ is n a po9t1 b a small disc4 ,?is is due to ! fact t ! rays ( light pass+ ?r\gh ! out] portions ( ! l5s are b5t m ?an ^? pass+ ?r\gh ! l5s 9 ! region ne> ! c5t]4 ,?is effect is %[n 9 ,fig4 #ab by ! usual mode ( repres5t+ x graphically4 ,"h ! figures #a1 #b1 #c1 #d1 repres5t di/ances f ! axis ( ! l5s1 & ! lett]s ,a#a1 ,a#b1 ,a#c1 ,a#d1 ! po9ts ( conv]g5ce ( ! rays f #a1 #b1 #c1 #d1 etc4 ,^! di/ances project$ upw>d on to ! produc$ l5s po9ts =m a curve :i* %[s at a glance ! ext5t & direction ( ! error due to ea* "p ( ! l5s4 ,?is in=mation is ( value :]e ! l5s is fitt$ ) an adju/able diafram4 ,) "s types ( correction %>p] def9ition may be obta9$ by r$uc+ ! ap]ture4 ,) o!rs1 h[ev]1 diafram+ impairs def9ition1 by de/roy+ ! balance betwe5 "u & ov] correction :i* av]ages to make a good image4 ,9 a]ial l5ses x is n cu/om>y to use diaframs1 z all ! light possible is desir$4 ,consequ5tly ! r$uction ( sph]ical ab]ration mu/ be accompli%$ by prop] *oice ( l5s elem5ts & _! arrangem5t4 ,(f ! axis ( ! l5s ! image ( a po9t s\rce takes on an irregul> %ape1 due to oblique sph]ical ab]ration or coma4 ,*romatic ,ab]ration4--,because ( ! inh]5t prop]ties ( ! glass ( :i* x is made1 a simple collective l5s does n behave 9 ! same way ) respect to light ( diff]5t colors4 ,if "o attempts1 ) su* a l5s1 to focus ^u a scre5 ! image ( a di/ant :ite light1 x w be f\nd t ! blue rays w n focus at ! same po9t z ! r$ rays1 b w come toge!r ne>] ! l5s4 ,mod]n photographic l5ses are comp\nd$ ( two or m k9ds ( glass 9 su* a way z to l>gely elim9ate ?is defect1 ! pres5ce ( :i* is detrim5tal to good def9ition4 ,su* l5ses are call$ a*romatic1 & ! prop]ty ( a l5s by virtue ( :i* ?is defect is elim9at$ is call$ its *romatic correction4 ,*romatic correction is nev] p]fect1 b two colors ( ! spectrum c be br\ght to a focus 9 ! same plane1 & to a c]ta9 ext5t ! dep>ture ( o!r colors f ?is plane c be controll$4 ,(f ! axis ( ! l5s out/&+ *romatic ab]ration results 9 a diff]5ce 9 ! size ( images ( diff]5t colors1 kn[n z lat]al *romatism4 ,l sph]ical ab]ration1 *romatic ab]ration is a contribut+ factor to ! size ( ! image ( a po9t s\rce1 :i* det]m9es ! def9+ p[] ( a l5s4 ,x is1 h[ev]1 an error ^: effect is to "s ext5t dep5d5t on ! k9d ( s5sitive plate us$4 ,two l5ses may give images ( ! same size 79 s f> z x is gov]n$ by *romatic ab]ration71 if a plate ( n>r[ spectral s5sitiv5ess is us$1 :ile giv+ images ( diff]5t size on pan*romatic plates ( m ext5d$ color s5sibility4 ,! *oice ( ! region ( ! spectrum = :i* *romatic correction is to be made is ?us gov]n$ by ! color ( ! photographically effective light4 ,:ile 9 ord9>y photography ! blue ( ! spectrum is mo/ important1 9 a]ial "w :]e color filt]s are habitually us$ ) iso*romatic plates ! gre5 is mo/ important1 & color correction c5t]$ ab\t ?is region con/itutes a real diff]5ce ( design peculi> to a]ial l5ses4 ,simil>ly ! g5]al use ( deep orange or r$ filt]s ) r$ s5sitive plates1 = heavy mi/ p5etration1 w\ld call = a %ift ( correction to t "p ( ! spectrum4 ,a/igmatism & ,cov]+ ,p[]4--,suppose ! l5s =ms at "s po9t (f its axis an image ( a cross4 ,suppose "o ( ! elem5ts ( ! cross to be on a radius f ! c5t] ( ! field1 ! o!r elem5t p>allel to a tang5t4 ,! rays =m+ ! images ( ^! two elem5ts ( ! cross are subject to some:at diff]5t treatm5t 9 _! passage ?r\gh ! l5s4 ,! curvature ( ! l5s surfaces is on ! :ole great] ) respect to ! rays f ! radial elem5t ?an to ^? f ! tang5tial elem5t4 ,!y are !re=e refract$ m /rongly & come to a focus ne>] ! l5s4 ,! arms ( ! cross are consequ5tly n all 9 focus at once4 ,?is error1 t]m$ a/igmatism1 is r well %[n 9 ,fig4 #ae1 :]e ! images ( ! outly+ conc5tric circles are %>p 9 ! radial1 b blurr$ 9 ! tang5tial direction4 ,a/igmatism c be l>gely comp5sat$ =1 & its "* controll$4 ,! mo/ usual correction br+s ! two images 9 focus toge!r bo? at ! axis1 & on a circle at "s di/ance out4 ,?is second locus ( co9cid5ce may or may n be 9 ! same plane z ! fir/1 dep5d+ on :i* disposition produces ! be/ av]age correction4 ,! mean betwe5 ! two foci det]m9es ! focal plane ( ! l5s1 :i* is 9 g5]al some:at curv$4 ,! cov]+ p[] ( a l5s is giv5 by ! size ( ! field :i* is suffici5tly flat & free f a/igmatism = ! purpose = :i* ! l5s is us$4 ,?is is l>gely det]m9$ by ! a/igmatism1 b ! o!r ab]rations are also important4 ,illum9ation4--,! am\nt ( light conc5trat$ by ! l5s on ea* elem5t>y area ( ! image det]m9es its brightness or illum9ation4 ,! ideal image w\ld1 ( c\rse1 be equally bright ov] its :ole area ( good def9ition1 & = l5ses ( n>r[ angle ?is is approximately true4 ,b :5 x is desir$ to cov] a wide angle ! "q ( illum9ation becomes s]i\s4 ,! relation%ip betwe5 angle f ! axis & illum9ation is t illum9ation is proportional to ! f\r? p[] ( ! cos9e ( ! angle4 ,?is relation%ip is %[n 9 ! foll[+ table3 ,angle ,image brightness #j #ajj p] c5t4 #aj #id4a p] c5t4 #bj #gh4j p] c5t4 #cj #ef4b p] c5t4 #dj #cd4d p] c5t4 #ej #ag4a p] c5t4 ,if ! field ( view is #fj1 :i* corresponds to an #ah #bd c5timet] plate ) a l5s ( #be c5timet] focus1 ! brightness is only #ef p] c5t41 & ! necess>y exposure at ! edge approximately #a4h times t at ! c5t]4 ,?is effect is %[n 9 ,fig4 #ae4 ,x is v noticeable if ! exposure is s %ort z to place ! outly+ areas 9 ! "u-exposure p]iod4 ,illu/ration3 ,,fig4 #ac4--;,b>rel & p9-cu%ion di/ortion4 ,di/ortion4--,sometimes a l5s is relatively free f all ! ab]rations1 m5tion$ above1 s t x gives %>p1 cle> images on ! plate1 yet ^! images may n be exactly simil> to ! objects !mselves z reg>ds _! geometrical proportions2 9 o!r words1 ! image w %[ di/ortion4 ,l5s di/ortion assumes two typical =ms1 illu/rat$ 9 ,fig4 #ac1 :i* %[s ! result ( photograph+ a squ>e net-"w ) l5ses suff]+ 9 ! "o case f 8b>rel0 di/ortion & 9 ! o!r f 8p9-cu%ion0 di/ortion4 ,9 ! fir/ ! corn]s are drawn 9 relative to ! sides2 9 ! latt] case ! sides are drawn 9 ) respect to ! corn]s4 ,ei!r sort is a s]i\s matt] 9 precision photography1 su* z a]ial photographic mapp+ aspires to become4 ,x mu/ be r$uc$ to a m9imum & its am\nt mu/ be accurately kn[n if negatives are to be measur$ = ! precise location ( photograph$ objects4 ,9 g5]al symmetrical l5ses give less di/ortion ?an ! unsymmetrical 7,fig4 #ad74 ,illu/ration3 ,,fig4 #ad4--;,arrangem5t ( elem5ts 9 two l5ses suitable = a]ial "w3 a1 ,zeiss ,tess>2 two simple & "o cem5t$ compon5ts 7unsymmetrical72 b1 ,hawkeye ,a]ial2 two positive elem5ts ( heavy b>ium cr[n1 two negative ( b>ium fl9t1 uncem5t$ 7symmetrical74 ,l5s ,te/+ & ,tol]ances = ,a]ial ,"w4--,simple & rapid comp>ative te/s ( l5ses may be made by photograph+ a te/ *>t1 consi/+ ( a l>ge flat surface on :i* are drawn v>i\s comb9ations ( geometrical figures--l9es1 squ>es1 circles1 etc4--calculat$ to %[ up any failures ( def9+ p[]4 ,= te/+ a]ial l5ses ! *>t %\ld be z l>ge z possible1 s t x may be photograph$ at a di/ance great en\gh = ! p]=mance ( ! l5s to be truly repres5tative ( its behavior on an object at inf9ite di/ance4 ,?is means 9 practice a *>t ( #d or #e met]s side1 to be photograph$ at a di/ance #bj to #cj times ! focal l5g? ( ! l5s4 ,illu/ration3 ,,fig4 #ae4--,photograph ( a l5s te/+ *>t1 %[+ failure 9 def9+ p[] outside area = :i* ! l5s is calculat$4 ,a typical photograph ( su* a *>t is %[n 9 ,fig4 #ae4 ,x reveals at a glance ! m conspicu\s l5s errors4 ,at ! sides & corn]s ! conc5tric circles %[ ! l5s's a/igmatism1 by ! cle> def9ition ( ! l9es radial to ! c5t] ( ! field & _! blurr+ 9 ! tang5tial direction4 ,! fall+ (f 9 illum9ation ) increas+ di/ance f ! c5t] is also exhibit$2 & ! blurr+ ( all detail outside ! rectangle = :i* ! l5s 0 calculat$ %[s t sph]ical1 *romatic1 & o!r ab]rations h become prohibitively l>ge4 ,b ! only complete te/ ( a l5s is ! quantitative measurem5t ( errors made on an optical b5*4 ,a po9t s\rce ( light1 :i* may at w be made ( any color ( ! spectrum1 is us$ z ! object & its image =m$ by ! l5s 9 a position :]e x c be accurately measur$ = location1 size1 & %ape by a microscope4 ,a *>t giv+ ! results ( su* a te/ is %[n 9 ,fig4 #af4 ,9 ! upp] left-h& corn] is %[n ! position ( ! focus = ! diff]5t colors ( ! spectrum4 ,bel[ ?is is record$ ! lat]al *romatism at #ba degrees1 9 t]ms ( ! diff]5ce 9 focus = a r$ & a blue ray4 ,bel[ ?is aga9 comes ! di/ortion1 or %ift ( ! image f its prop] position1 = v>i\s angles 7plott$ at ! extreme "r7 f ! l5s axis4 ,to ! "r ( ?is is ! image size1 at ea* angle1 & f9ally1 to ! "r ( ! diagram1 are plott$ ! di/ances ( ! two a/igmatic foci f ! focal plane1 toge!r ) ! mean ( ! two foci1 :i* practically det]m9es ! %ape ( ! field4 ,an important po9t to notice is t ^! data are uni=mly plott$ 9 t]ms ( a l5s ( #ajj millimet]s focal l5g? irrespective ( ! actual focal l5g? ( ! l5s measur$4 ,?us ?is p>ticul> *>t is = a #ej c5timet] l5s b w\ld be plott$ on ! same scale = a #be or a #ajj c5timet] l5s4 ,und]ly+ ?is practice is ! assumption t all ! *>act]i/ics ( l5ses ( ! same design & ap]ture are directly proportional to _! focal l5g?4 ,if ?is 7 s1 !n a #ej c5timet] l5s w\ld give d\ble ! size ( image t a #be c5timet] does1 & s on4 ,z a matt] ( fact1 te/ %[s t ! size ( ! image does n increase s rapidly z ! focal l5g?2 s t :ile ! image size = a #be c5timet] l5s w\ld be1 say1 4#je millimet]s p] #ajj millimet]s focal l5g?1 x w be only 4#jc or 4#jd millimet]s p] #ajj millimet]s focal l5g? = a #ej c5timet] l5s4 ,! actual size ( a po9t image w !re=e be great]1 ?\gh n proportionately great]4 ,illu/ration3 ,,fig4 #af4--;,*>t record+ measurem5ts ( l5s *>act]i/ics4 ,! *>t pres5ts te/s on a good quality l5s1 & s gives a good idea ( ! p]missible magnitude ( ! v>i\s errors4 ,9 _m ways ! mo/ important figure is t = image size1 includ+ z x does ! result ( all ! ab]rations4 ,9 ! example giv51 ?is v>ies f 4#jge to 4#ae mm4 actual size4 ,= ! same type ( l5s ( #be c5timet]s focus ?is range w be f 4#je to 4#aj mm4 ,s9ce ^! are commonly us$ focal l5g?s1 a good av]age figure = image size1 commonly us$ 9 a]ial photographic calculations1 is mm4 ,9 reg>d to a/igmatic tol]ances1 ! two a/igmatic foci %\ld n be sep>at$ at any po9t by m ?an #f to #g millimet]s1 & ! mean ( ^! %\ld n deviate f ! true flat field by m ?an millimet]1 9 ea* case ! figures be+ bas$ on ! conv5tional #ajj millimet]s focal l5g?4 ,di/ortion %\ld n be ov] 4#jh millimet] at #ah or 4#bj millimet] at #bd f ! axis 7p] #ajj millimet]s focal l5g?74 ,l5s ,ap]ture4--,9 ! simple l5s ! ap]ture is m]ely ! diamet]4 ,9 comp\nd l5ses ! ap]ture is n ! l9e> op5+ b ! effective op5+ ( an int]nal diafram4 ,photographically1 h[ev]1 ap]ture has come to h a m ext5sive mean+4 ,:ile 9 ! telescope ! actual diamet] ( an objective is p]haps ! mo/ important figure1 & 9 ! microscope ! focal l5g?1 9 photography ! really important feature is ! am\nt ( light or illum9ation4 ,?is is det]m9$ by l5s op5+ & focal l5g? toge!r2 specifically1 by ! ratio ( ! l5s area to ! focal l5g?4 ,! common sy/em ( repres5t+ photographic l5s ap]ture is by ! ratio ( focal l5g? to l5s diamet]1 ! l5s be+ assum$ to be circul>4 ,?us ,f_/#e 7(t5 writt5 ,f4#e7 indicates t ! diamet] is "o-fif? ! focal l5g?4 ,two po9ts are to be con/antly borne 9 m9d 9 connection ) ?is sy/em ( repres5tation4 ,fir/1 all l5ses ( ! same ap]ture 7z s repres5t$7 give ! same illum9ation ( ! plate 7except = diff]5ces due to loss ( light by absorption & reflection 9 ! l5s sy/em74 ,?is foll[s simply f ! fact t ! illum9ation ( ! plate is directly proportional to ! squ>e ( ! l5s diamet]1 & inv]sely z ! squ>e ( ! focal l5g?4 ,secondly1 ! illum9ation ( ! plate is inv]sely z ! squ>e ( ! num]ical "p ( ! expression = ap]ture4 ,t is1 l5ses ( ap]ture ,f_/#d4e & ,f_/#f give images ( relative brightness 7#f_/d4e7b #a4gh4 ,:at l5s ap]ture1 & !re=e :at image brightness1 is feasible1 is det]m9$ *iefly by ! angul> field t mu/ be cov]$ ) any giv5 excell5ce ( def9ition4 ,! l>ge/ ap]ture ord9>ily us$ = "w requir+ good def9ition & flat field free f di/ortion is ,f_/#d4e4 ,ana/igmatic l5ses ( ?is ap]ture cov] an angle ( #af to #ah f ! axis satisfactorily1 :i* corresponds to an #ah #bd c5timet] plate ) a l5s ( #ej c5timet]s focus4 ,l5ses ) ap]ture z l>ge z ,f_/#c4e 7 us$ to "s ext5t 9 ,g]man h& cam]as ( #be c5timet]s focal l5g?1 ) plates ( #i #ab c5timet]s4 ,engli% & ,am]ican l5ses ( ?is latt] focal l5g? 7 commonly ( ap]ture ,f_/#d4e1 design$ to cov] a #d #e in* plate4 ,z a g5]al rule ! great] ! focal l5g? ! small] ! ap]ture--a relation%ip prim>ily due to ! difficulty ( secur+ optical glass 9 l>ge pieces4 ,?us :ile #ej c5timet] l5ses ( ap]ture ,f_/#d4e are reasonably easy to manufacture1 ! practicable ap]ture = quantity production is ,f_/#f1 & = #abj c5timet] l5ses1 ,f_/#aj4 ,?is means t a v great sacrifice ( illum9ation mu/ be fac$ to secure ^! great] focal l5g?s4 ,z is to be expect$ f ! /ate ( ! optical glass indu/ry1 ! ,g]man l5ses 7 ( g5]ally l>g] ap]ture = ! same focal l5g?s ?an 7 ^? ( ! ,allies4 ,besides ! ,f_/#c4e l5ses already m5tion$1 _! #ej c5timet] l5ses 7 commonly ( ap]ture ,f_/#d4h1 _! #abj c5timet] l5ses ( ap]ture ,f_/#g1 or ( ab\t d\ble ! illum9at+ p[] ( ! ,fr5* l5ses ( ! same size4 ,dem&s = l>ge cov]+ p[] also result 9 small] ap]ture4 ,! #bf c5timet] l5ses us$ on ,fr5* h& cam]as utiliz+ #ac #ah c5timet] plates 7 commonly ( ap]ture ,f_/#f or ,f_/#e4f4 ,! l5s ( l>ge/ cov]+ p[] decid$ on = use 9 ! ,am]ican s]vice 0 ( #ab in* focus1 to be us$ ) an #ah #bd c5timet] plate 7extreme angle #bf72 ! l>ge/ satisfactory ap]ture = ?is l5s is ,f_/#e4f4 ,ord9>ily ! "q ( ap]ture is closely connect$ ) t ( diaframs1 :]eby ! l5s ap]ture may be r$uc$ at w4 ,diaframs h be5 v little us$ 9 a]ial photography4 ,all ! ap]ture t c be obta9$ & m is ne$$ to secure adequate photographic action ) ! %ort exposures requir$ "u ! conditions ( rapid motion & vibration peculi> to ! airplane4 ,any excess ( light1 ov] ! m9imum necess>y to secure prop] photographic action1 is f> bett] (fset by increase ( %utt] spe$ or by introduction ( a color filt]4 ,= ?is reason ,am]ican a]ial l5ses 7 made )\t diaframs4 ,9 ! ,g]man cam]as1 h[ev]1 adju/able diaframs are provid$ 7,fig4 #dc71 controll$ f ! top ( ! cam]a by a rack & p9ion4 ,9 ! cam]a mo/ us$ 9 ! ,italian s]vice an adju/able diafram is provid$1 b ?is is occasion$ by ! employm5t ( a betwe5-!-l5s %utt] ( fix$ spe$1 s t ! only way exposure c be regulat$ is by ap]ture v>iation1 a me?od :i* has little to recomm5d x4 ,! ,"q ( ,focal ,l5g?4--,9 a]ial photography ! l5s is inv>iably us$ at fix$1 inf9ity1 focus4 ,"u ^! conditions ! simple relation%ip holds t ! size ( ! image is directly proportional to ! focal l5g? & inv]sely proportional to ! altitude4 ,if any *os5 scale is desir$ = ! picture ! *oice ( focal l5g? is det]m9$ by ! height at :i* x is necess>y to fly4 ,?is at lea/ w\ld be ! case 7 !re no limitation to ! practicable focal l5g?--:i* means cam]a size--& 7 "o limit$ to ! orig9al size ( ! picture z tak52 t is1 7 ! process ( enl>gem5t n available4 ,b ! possibility ( us+ ! enl>g+ process br+s 9 o!r que/ions3 ,is ! def9+ p[] ( a %ort focus l5s z good 9 proportion to its focal l5g? z t ( a long focus l5s8 ,if s a p]fect enl>gem5t f a negative made by a %ort focus l5s w\ld be id5tical ) a contact pr9t f a negative made ) a l5s ( long] focus4 ,is def9+ p[] lo/ 9 ! enl>g+ process ) its necess>y employm5t ( a l5s :i* has its own errors ( def9ition & :i* mu/ be accurately focuss$8 ,c]ta9 factors :i* ent] into comp>isons ( ?is sort 9 o!r l9es ( "w1 su* z a/ronomical photography1 play little "p "h4 ,^! are1 fir/1 ! optical resolv+ p[] ( ! l5s1 :i* is condition$ by ! ph5om5a ( diffraction1 & is directly z ! diamet]2 &1 second1 ! size ( ! gra9 ( ! plate emulsion4 ,! fir/ ( ^! does n ent] directly1 because ! size ( a po9t image on ! axis ( ! l5s1 due m]ely to diffraction1 is v mu* less ?an t giv5 by any photographic l5s :i* has be5 calculat$ to give def9ition ov] a l>ge field1 in/ead ( ! m9ute field ( ! telescope4 ,yet x may contribute t[>d some:at bett] def9ition ) a long focus l5s because ( ! actually l>g] diamet] ( su* l5ses4 ,! second factor is n important1 because1 z w be se5 lat]1 ! resolv+ p[] ( ! plates suitable = a]ial photography is consid]ably great] ?an t ( ! l5s4 ,! emulsion gra9 is 9 fact only a qu>t] or a fif? ! size ( ! image z giv5 by a #be c5timet] l5s1 & enl>gem5ts ( m ?an two or ?ree times are r>ely want$4 ,a s]ies ( exp]im5ts 0 made = ! ,u4 ,s4 ,air ,s]vice to te/ out ^! que/ions1 us+ a numb] ( repres5tative l5ses ( all focal l5g?s1 bo? at _! work+ ap]tures & at id5tical ap]tures = all4 ,) reg>d to l5s def9+ p[]1 z %[n by ! size ( a po9t image1 ! answ] has already be5 report$ 9 a previ\s section4 ,l5ses ( long focus give a relatively small] image ?an l5ses ( ! same design ( %ort focus4 ,9 reg>d to ! :ole process ( mak+ a small negative & enl>g+ x1 ! loss ( def9ition is q m>k$1 z comp>$ to ! pictures ( ! same scale made by contact pr9t+ f negatives tak5 ) long] focus l5ses4 ,?is answ] is cle>-cut only = l5ses calculat$ to give ! same angul> field4 ,?us a #aj in* l5s cov]+ a #d #e in* plate has ab\t ! same angle z a #ej c5timet] l5s = an #ah #bd c5timet] plate4 ,:51 h[ev]1 x comes to ! long] foci1 su* z #abj c5timet]s1 ! practical limitation to plate size 7#ah #bd cm47 has be5 pass$1 & ! angul> field is less ?an half t ( ! #ej c5timet] l5s4 ,! #abj c5timet] l5s ne$ only be design$ = ?is small angle1 ) consequ5t great] opportunities = r$uction ( sph]ical ab]ration4 ,x is !re=e an op5 "q :e!r a #ej c5timet] l5s design$ to cov] a plate ( l9e> dim5sions #ej_/abj times t us$ ) ! regul> #ej c5timet] l5s c\ld n be produc$ ( su* quality t x w\ld yield enl>gem5ts equal to contacts f a #abj c5timet] l5s4 ,if s1 l5ses ( l>g] ap]ture c\ld be us$1 & a consid]able sav+ 9 space requirem5ts effect$4 ,focal l5g?s dur+ ! ,great ,w> 7 decid$ by ! nature ( ! milit>y detail :i* 0 to be reveal$ & by ! altitudes to :i* fly+ 0 re/rict$ 9 milit>y op]ations4 ,9 ! fir/ ?ree ye>s ( ! w> ! developm5t ( def5ces aga9/ aircraft =c$ planes to m\nt /eadily high]1 s t ! orig9al ?ree or f\r ?\s& feet 7 pu%$ to #ae1jjj1 #ah1jjj1 & ev5 high]4 ,l5ses ( long focus 7 9 dem&1 lead+ ultimately to ! use ( "s ( z mu* z #abj c5timet]s 7,fig4 #da74 ,9 ! la/ mon?s ( ! w> ! resumption ( op5 fight+ made m9ute record+ ( tr5* details ( less weight1 :ile ! prepond]ance ( alli$ air /r5g? p]mitt$ l[] fly+4 ,9 consequ5ce1 l5ses ( %ort] focus & wid] angle came to ! =e1 suitable = quick reconnaissance ( ! ma9 features ( new c\ntry4 ,at ! close ( ! w> ! foll[+ focal l5g?s 7 /&>d 9 ! ,u4 ,s4 ,air ,s]vice1 & may be consid]$ z well-suit$ = milit>y ne$s4 ,peace may develop q diff]5t requirem5ts4 ,focal l5g? ,ap]ture ,plate size #aj in* ,f_/#d4e #d #e in* #bf cm4 ,f_/#f #ac #ah cm4 #ab in* ,f_/#e4f #ah #bd cm4 #bj in* ,f_/#f4c to ,f_/#d4e #ah #bd cm4 #dh in* ,f_/#aj to ,f_/#h #ah #bd cm4 ,! "q ( ! use ( telephoto l5ses 9 place ( l5ses ( long focus is frequ5tly rais$4 ,l5ses ( ?is type comb9e a div]g+ 7concave7 elem5t ) ! normal conv]g+ sy/em1 :]eby ! effect ( a long focus is secur$ )\t an equival5t l5s-to-plate di/ance4 ,?is r$uction 9 8back focus0 may be f a qu>t] to a half4 ,7 x possible to obta9 ! same def9ition ) telephoto l5ses z ) l5ses ( ! same equival5t focus1 !y w\ld inde$ be em95tly suitable = a]ial "w because ( _! economy ( l5g?4 ,b exp]i5ce ?us f> has %[n t ! p]=mance ( telephoto l5ses1 z to def9ition & fre$om f di/ortion1 is di/9ctly inf]ior1 s t x is be/ to hold to ! long focus l5s ( ! ord9>y type4 ,l5ses ,suitable = ,a]ial ,photography4--,among ! v l>ge numb] ( mod]n ana/igmat l5ses _m 7 f\nd suitable = airplane cam]as & 7 us$ ext5sively 9 ! w>4 ,a p>tial li/ foll[s3 ,! ,cooke ,avi>1 ,! ,c>l ,zeiss ,tess>1 ! ,go]z ,dogm>1 ! ,hawkeye ,a]ial1 ! ,baus* & ,lomb ,s]ies ,ic & ,i,ib ,tess>s1 ! ,aldis ,triplet1 ! ,b]?iot ,olor4 ,! ,"q ( ,plate ,size & ,%ape4--,plate size is det]m9$ by a numb] ( consid]ations1 sci5tific & practical4 ,if ! type ( l5s is fix$ by requirem5ts z to def9ition1 !n ! dim5sions ( ! plate are limit$ by ! cov]+ p[]4 ,f ! /&po9t ( economy ( flights & ( ease ( recogniz+ ! locality repres5t$ 9 a negative1 by its inclusion ( kn[n po9ts1 l5ses ( z wide angle z possible %\ld be us$4 ,if ! focus is long1 ?is means l>ge plates1 :i* are bulky & heavy4 ,if ! f9e/ r5d]+ ( detail is n requir$ a small] scale may be employ$1 utiliz+ %ort focus l5ses & correspond+ly small] plates4 ,?us a six in* focus l5s on a #d #e in* plate w\ld be z good f ! /&po9t ( angul> field z a #ab in* on an #h #aj in* plate4 ,?is is apt to be ! condition ) respect to mo/ peace-"t a]ial photography1 :i* may be expect$ to free itself quickly f ! huge plates & cam]as ( w> orig94 ,= "w 9 :i* great fre$om f di/ortion ( any sort is imp]ative1 small plates w be necess>y1 = two reasons4 ,"o is t ! *>act]i/ic l5s di/ortions are l>gely conf9$ to ! outly+ portions ( ! field4 ,! o!r is t a wide angle ( view inevitably means t all objects ( any elevation at ! edge ( ! picture are %[n p>tly 9 face z well z 9 plan1 :i* prev5ts satisfactory jo9+ ( successive views 7,fig4 #abh74 ,9 mak+ a mosaic map ( a city1 if a wide angle l5s is employ$ ) l>ge plates1 ! build+s ly+ along ! junctions ( ! pr9ts c be mat*$ up only = "o level4 ,if ?is is ! gr\nd level1 z x w\ld be to keep ! scale ( ! map correct1 ! ro(s w h to be sacrific$4 ,9 extreme cases a h\se at ! edge ( a junction may ev5 %[ m]ely z a front & re>1 ) no ro(1 :ile 9 any case ! abrupt *ange at ^! edges f see+ "o side ( all objects to see+ ! opposite side is n pleas+4 ,! table 9 a prec$+ section gives ! relation ( plate size to focal l5g? f\nd be/ on ! :ole = milit>y ne$s4 ,deviations f ^! proportions 9 bo? directions are met )4 ,9 ! ,engli% s]vice ! ,,lb cam]a1 :i* uses #d #e in* plates1 is equipp$ ) l5ses ( v>i\s focal l5g?s1 up to #bj in*es4 ,! ,g]man practice1 z well z ! ,italian1 0 almo/ uni=m use ( #ac #ah c5timet] plates = all focal l5g?s4 ,t[>d ! end ( ! w>1 h[ev]1 "s ,g]man cam]as ( #ej c5timet] focal l5g? 7 9 use employ+ plates #bd #cj c5timet]s4 ,x w be recogniz$ t ^! plate sizes are *os5 f ^? 9 common use be=e ! w>4 ,a simil> obs]vation holds ) ev5 great] =ce on ! "q ( plate %ape4 ,curr5t plate %apes h be5 *os5 *iefly ) ref]5ce to secur+ pleas+ or arti/ic effects ) ! common types ( pictures tak5 on ! gr\nd4 ,^! %apes are n necess>ily ! be/ = a]ial photography4 ,inde$ ! :ole "q ( plate %ape %\ld be tak5 up f ! beg9n+1 ) direct ref]5ce to ! problems ( a]ial photography & photographic app>atus4 ,a few illu/rations w make ?is cle>1 tak+ ,fig4 #ag z a basis4 ,if x is desir$ to d spott+ 7! photography ( s+le objectives71 ! be/ plate %ape w\ld be circul>1 = t %ape utilizes ! entire cov]+ area ( ! l5s4 ,if x is desir$ to make successive ov]lapp+ pictures1 ei!r = mapp+1 or = ! production ( /]eoscopic pairs1 a rectangul> %ape is indicat$4 ,if ! process ( plate *ang+ is difficult or sl[1 x is advisable1 9 ord] to give maximum "t = ?is op]ation1 to h ! long side ( ! rectangle p>allel to ! l9e ( flight 7indicat$ by ! arr[74 ,if economy ( flights is a consid]ation1 z 9 mak+ a mosaic map ( a l>ge area1 x is advantage\s to h z wide a plate z ! cov]+ p[] ( ! l5s w p]mit4 ,ref]5ce to ,fig4 #ag %[s t ?is means a plate ( small dim5sions 9 ! direction ( flight4 ,if ! *ang+ ( plates or film is quick & easy1 ! maximum use ( ! l5s's cov]+ p[] is made by su* a rectangle ^: long side approximates ! dim5sions ( ! l5s field diamet]4 ,?is is 9 fact ! *oice made 9 ! ,g]man film mapp+ cam]a 7,figs4 #fa & #fc71 ^: picture is #f #bd c5timet]s4 ,an objection to ?is f ! pictorial side1 lies 9 ! _m junction l9es cutt+ up ! mosaic4 ,ano!r objection1 if ! plane does n hold a /eady c\rse1 is ! failure to make ov]laps on a turn4 7,fig4 #fb47 ,"h z ev]y:]e ! problem is to decide on ! mo/ practical compromise betwe5 all requirem5ts4 ,illu/ration3 ,,fig4 #ag4--,possible *oices ( plate %ape4 ,focuss+4--,! process ( focuss+ a]ial cam]as 0 at fir/ deem$ a my/]y1 ?\gh undes]v$ly s4 ,a belief 0 long curr5t t 8gr\nd0 focus & 8air0 focus diff]4 ,9 o!r words1 t a cam]a focuss$ ^u a di/ant object on ! gr\nd w\ld n be 9 focus = an object ! same di/ance bel[ ! cam]a :5 9 ! plane4 ,belief 9 ?is my/]i\s diff]5ce w5t s f> t c]ta9 in/ruction books describe 9 detail ! process ( focuss+ a cam]a by trial exposures f ! air4 ,c>eful laboratory te/s p]=m$ = ! ,u4 ,s4 ,air ,s]vice %[$ t nei!r l[ temp]ature nor l[ pressure1 su* z w\ld be met at high altitudes1 alt] ! focus ( any ord9>y l5s by a significant am\nt1 & t ! possible contraction ( ! cam]a body 0 ( negligible effect on ! focus 7n m ?an #a_/bjj p] c5t4 p] degree c5tigrade ) a metal cam]a74 ,9 complete h>mony ) ^! te/s has be5 ! exp]i5ce t if ! gr\nd focuss+ is done c>efully1 by accurate means1 !n ! air focus is correct4 ,! :ole matt] ?us becomes "o ( precision focuss+4 ,! be/ me?od1 applicable if ! air is /eady1 is to focus by p>allax4 ,! gr\nd glass focuss+ scre5 is m>k$ 9 ! c5t] ) a p5cill$ cross4 ,ov] ?is is m\nt$1 ) ,canada balsam1 a ?9 microscope cov]-glass4 ,! cam]a is direct$ on an object a mile or m away1 & ! image =m$ by ! l5s is exam9$ by a magnify+ glass ?r\gh ! virtual hole =m$ by ! affix$ cov]-glass4 ,) ! p5cil l9e 9 focus ! head is mov$ f side to side4 ,if ! image & p5cil m>k co9cide !y w move toge!r z ! head is mov$4 ,if ! image moves away f ! p5cil m>k & 9 ! same direction z ! eye moves1 ! image is too ne> ! l5s4 ,if ! image moves away 9 ! opposite direction to ! motion ( ! eye1 x is too f> f ! l5s4 ,9 ei!r case ! focus is to be correct$ accord+ly4 ,9 place ( a di/ant object1 :i* may wav] ) ! motion ( ! air1 we may use an image plac$ at inf9ity by optical means4 ,! collimator1 an in/rum5t = do+ ?is1 consi/s ( a te/ object 7l9es1 circles1 etc47 plac$ accurately at ! focus ( a telescope objective4 ,! cam]a l5s is plac$ aga9/ ?is & focuss$ by p>allax1 z ) a di/ant object4 ,collimators are employ$ 9 cam]a factories1 & %\ld be "p ( ! equipm5t ( base laboratories :]e repair+ & ov]haul+ ( cam]as is done4 ,l5s ,m\nts4--,all t is requir$ = ! m\nt+ ( an a]ial cam]a l5s is a rigid plat=m1 ) provision = en\gh motion ( ! l5s to adju/ its focus accurately4 ,z already expla9$1 ! l5s works at fix$1 inf9ity1 focus1 & !re=e ne$s no adju/m5t dur+ use4 ,x mu/ be held f> m rigidly ?an w\ld be possible by ! bell[s1 :i* is an almo/ inv>iable adjunct ( focuss+ cam]as4 ,! use ( ord9>y types ( h& cam]as on a plane is r>ely successful j because ( ! bell[s1 :i* is /ra9$ & rattl$ by ! ru% ( w9d4 ,! l5s m\nt+s ?us f> us$ h be5 simple affairs4 ,9 ! ,fr5* cam]as ! l5s is m]ely screw$ into a flange :i* 9 turn is fa/5$ by screws to a plat=m 9 ! cam]a body4 ,adju/m5t = focuss+ is n provid$2 in/ead1 ! flange is rais$ on ?9 metal r+s or wa%]s1 cut ( su* ?ickness by trial z to br+ ! l5s to focus1 once & = all4 ,! ,u4 ,s4 ,air ,s]vice me?od ( m\nt+ is to provide ! l5s b>rel ) a long ?read1 :i* screws into a flange t 9 turn is m\nt$ on a plat=m 9 ! cam]a cone1 by means ( ?umb-screws4 ,! l5s is focuss$ by screw+ 9 & out1 & !n clamp$ by a screw ?r\gh ! side1 be>+ on ! ?read4 ,! :ole m\nt may be quickly remov$ by loos5+ ! ?umb-screws1 & once focuss$ 9 "o cone1 c be transf]r$ to ano!r simil>1 ma*9e-made cone )\t *ange ( focus4 ,fig4 #ah %[s a #bj in* l5s m\nt$ 9 ?is mann]4 ,! photograph %[s z well ! r+ on ! front ( ! l5s by means ( :i* circul> color filt]s may be held 9 place4 ,?is r+ screws d[n on ! filt]1 & ! cat* is dropp$ into ! ne>e/ v]tical groove to ! tight position4 ,illu/ration3 ,,fig4 #ah4--ej c5timet] ,f_/#f l5s 9 ,u4 ,s4 /&>d m\nt1 %[+ color filt] reta9+ r+ & cat*4 ,a some:at diff]5t & bett] me?od ( tight5+ ! l5s 9 ! flange1 :5 focuss$1 has be5 adopt$ 9 ! ,engli% l5s m\nt1 :i* is 9 g5]al simil> to ! ,am]ican4 ,! ?read$ "p ( ! flange is split by a slot cut p>allel to ! flange base1 & a screw is run into ! flange f ! front1 ?r\gh ! split portion4 ,by tight5+ ?is screw1 :i* is always accessible1 ! split "p ( ! flange is squeez$ toge!r1 ?us rigidly hold+ ! l5s b>rel4 ,,*apt] ,v ,,! ,,%utt] ,p]missible ,exposure 9 ,airplane ,photography4--,a def9ite limitation to ! l5g? ( exposure 9 airplane cam]as is set by ! motion ( ! plane4 ,if we repres5t ! spe$ ( ! plane by ,s1 ! altitude ( ! plane by ,a1 & ! focal l5g? ( ! l5s by ,f1 we obta9 at once f ! diagram 7,fig4 #ai71 t s1 ! rate ( movem5t ( ! image on ! plate1 is giv5 by ! relation1 s ,f ------ ------ ,s ,a ,if we call ! p]missible movem5t d1 !n ! p]missible exposure "t1 t1 is giv5 by ! relation-- d ,ad t ------ -------- s ,,fs ,z a repres5tative num]ical case1 express+ all quantities 9 c5timet]s & 9 c5timet]s p] second1 let ,f #ej1 ,s #bj1jjj1jjj_/cfjj 7#bjj kilomet]s p] h\r71 & ,a #cjj1jjj1 !n #ej #bj1jjj1jjj s ------------------------------ 4#i c5timet]s #cjj1jjj #cfjj ,if we take = ! p]missible undetectable movem5t1 4#ja c5timet]1 :i* is1 z has be5 %[n1 a reasonable figure = l5s def9+ p[]1 we h1 !n1 t ! longe/ p]missible exposure is 4#jaa second--9 r\nd numb]s1 "o-hundr$?4 ,9 fly+ ) a sl[ plane1 or 9 fly+ aga9/ ! w9d1 ! exposure c sometimes be increas$ to z mu* z d\ble ?is l5g?4 ,dim9i%+ ,f w\ld simil>ly ext5d ! all[able exposure1 b ! ratio ( ,f to ,a approximates to a con/ant 9 actual practice2 9 o!r words1 a c]ta9 resolution & size ( image h be5 f\nd desirable4 ,if fly+ is =c$ high]1 a long] focus l5s is us$2 if l[] fly+ is possible1 a l5s ( %ort] focus4 ,?is relation%ip has1 ( c\rse1 be5 d]iv$ f w>-"t exp]i5ce4 ,probably mu* ( ! prospective peace-"t mapp+ "w w impose sub/antially easi] requirem5ts z to def9ition & w ?us all[ long] exposures4 ,illu/ration3 ,,fig4 #ai4--,relative motion ( plane & photographic image4 ,= l[ oblique views ! longe/ exposure is mu* less4 ,tak+ #de degrees z a repres5tative angle = ! =egr\nd1 & #ejj met]s z a repres5tative height1 ! value ( t becomes #a_/fjj4 ,^! figures w illu/rate two important po9ts3 !y %[ h[ sev]e is ! limitation z to exposure1 ) ! consequ5t heavy dem& on l5s & s5sitive mat]ial spe$2 & !y %[ h[ important x is to secure a %utt] ) ! maximum light-giv+ p[] = a specifi$ l5g? ( exposure4 ,?is leads to a /udy ( ! *>act]i/ics z to effici5cy ( ! two common types ( %utt]1 namely1 %utt]s at or betwe5 ! l5s1 & focal-plane %utt]s4 ,*>act]i/ics ( ,%utt]s ,locat$ at ! ,l5s4--,( ! v>i\s %utt]s locat$ at ! l5s ! mo/ common is ! type t is clumsily b descriptively t]m$ ! 8betwe5-!-l5s0 %utt]4 ,?is is compos$ ( ?9 h>d rubb] or metal leaves or sectors :i* ov]lap & :i* are pull$ op5 to make ! exposure4 ,x may require two op]ations1 "o = sett+ & "o = expos+1 or x may1 z 9 "s makes1 set & expose by a s+le motion4 ,clock escapem5ts1 or "s =m ( frictional resi/ance1 are dep5d$ on to control ! int]val betwe5 op5+ & clos+4 ,?is %utt] is ! "o almo/ univ]sally employ$ on small h& cam]as & on all l5ses up to ab\t two in*es diamet]4 ,x gives spe$s sometimes m>k$ z high z #a_/cjj second1 al?\gh usually n ov] #a_/ajj on actual te/4 ,betwe5-!-l5s %utt]s h be5 us$ to "s ext5t on ! %ort] focus 7up to #be c5timet]7 a]ial cam]as1 notably 9 ! ,italian s]vice4 ,!y suff]1 h[ev]1 f two limitations4 ,9 ! fir/ place we h n yet solv$ ! me*anical problems met ) 9 try+ to make ! %utt] ( l>ge size 7z = #ej c5timet] ,f_/#f l5ses7 at ! same "t to give high spe$s4 ,9 ! second place ! effici5cy ( ! type is l[ because a l>ge "p ( ! exposure "t is occupi$ by ! op5+ & clos+ ( ! sectors4 ,if we def9e ! effici5cy ( a %utt] z ! ratio ( ! am\nt ( light x transmits dur+ ! exposure to ! am\nt ( light x w\ld transmit 7 x wide op5 dur+ ! :ole p]iod1 !n ! effici5cy ( ! ord9>y betwe5-!-l5s %utt] is ( ! ord] ( #fj p] c5t4 ,?is means #a4f times ! motion ( ! image = ! same photographic action t we %\ld h ) a p]fect %utt]4 ,! accompany+ photographic record 7,fig4 #bj7 ( ! op5+ & clos+ process ( ?is type ( %utt] cle>ly illu/rates its defici5cies4 ,illu/ration3 ,,fig4 #bj4--;,effective l5s op5+ at equal int]vals ( "t3 7a7 dur+ focal plane %utt] exposure2 7b7 dur+ betwe5-!-l5s %utt] exposure4 ,*>act]i/ics ( ! ,focal-,plane ,%utt]4--,long be=e ! days ( a]ial photography ! problem ( a high-effici5cy high-spe$ %utt] = photograph+ mov+ objects on ! gr\nd--railway tra9s or rac+ automobiles--_h already l$ to ! developm5t ( ! focal-plane %utt]4 ,?is is a type peculi>ly adapt$ to ! problems ( ! airplane cam]a4 ,x consi/s ess5tially ( a curta91 runn+ at high spe$ close to ! photographic plate1 ! exposure be+ giv5 by a n>r[ rectangul> slot4 ,if ! focal-plane %utt] is 9 virtual contact ) ! s5sitive surface ! effici5cy1 z def9$ above1 is #ajj p] c5t41 s9ce ! :ole cone ( rays f ! l5s illum9ates ! plate dur+ ! :ole "t ( exposure4 ,b if ! curta9 is n c>ri$ close to ! plate ! effici5cy falls (f rapidly ) di/ance1 especially s = small ap]tures ( ! slot4 ,illu/ration3 ,,fig4 #ba4--;,calculation ( focal plane %utt] effici5cy4 ,! effici5cy ( ! focal-plane %utt] may be calculat$ z foll[s3 ,let ! focal l5g? ( ! l5s be ,f1 its diamet] be ,f_/,n1 ! wid? ( ! slot be a1 & ! di/ance f plate to curta9 d 7,fig4 #ba74 ,n[ if ! curta9 is mov+ at a uni=m spe$1 ! "t tak5 = ! slot to trav]se ! :ole cone ( rays1 f ! in/ant x ent]s till ! in/ant x leaves1 w be directly proportional to d 7,f7 d ------ 7------7 a ------ a ,f 7,n7 ,n ,if ! curta9 7 9 contact ) ! plate ! "t tak5 = ! same am\nt ( light to rea* ! s5sitive surface w\ld be proportional to a4 ,aga9 def9+ %utt] effici5cy z ! ratio ( ! light transmitt$ to :at w\ld h be5 transmitt$ 7 ! %utt] fully op5 = ! total "t ( exposure1 ! effici5cy1 ,e1 is giv5 at once by ! expression-- a ,e ---------------------- d_/,n a ,z an example let ! l5s ap]ture be ,f_/#f1 s t ,n #f2 let d #a1 & a #a1 !n ,e #f_/g4 ,9 ! ,fr5* de,maria cam]as1 :]e d #d c5timet]s1 ,e #fj p] c5t4 = ! ap]ture assum$1 :i* is repres5tative4 ,fig4 #bb exhibits diagrammatically ! *ief *>act]i/ics ( ! focal plane %utt]4 ,illu/ration3 ,,fig4 #bb4--;,*>act]i/ics ( focal plane %utt]4 ,9 view ( ! necessity = "s di/ance betwe5 %utt] & plate x is obvi\sly important to keep a z l>ge z possible1 dep5d+ = ! requisite %utt] spe$ on ! velocity ( ! curta94 ,l>ge ap]ture & high curta9 spe$ are also f\nd to be desirable :5 we consid] ! di/ortion produc$ by ! focal-plane %utt]4 ,di/ortions ,produc$ by ! ,focal-plane ,%utt]4--,:ile ! "t ( exposure ( any po9t on ! plate c1 ) ! focal-plane %utt]1 easily be made #a_/ajj second or less1 ! :ole p]iod dur+ :i* ! %utt] is mov+ is mu* great] ?an ?is4 ,= in/ance1 a #a c5timet] op5+ :i* gives #a_/ajj second exposure takes second to move across a #aj c5timet] plate1 or ne>ly second = an #ah c5timet] plate4 ,) a mov+ airplane ?is means t ! po9t ( view at ! end ( ! exposure has mov$ =w>d comp>$ to t at ! beg9n+1 by ! am\nt ( motion ( ! plane 9 ! int]val4 ,if ! %utt] moves 9 ! direction ( motion ( ! plane ! image w be magnifi$2 if 9 ! opposite direction1 x w be compress$ along ! axis ( motion4 ,! am\nt ( ?is di/ortion is calculat$ z foll[s3 ,let ! velocity ( ! plane be ,v1 & t ( ! %utt] be v4 ,let ! focal l5g? ( ! cam]a be ,f1 & ! altitude ,a4 ,if ! cam]a 7 /ation>y1 a plate ( l5g? l w\ld receive on its surface an image correspond+ to a di/ance ,a_/,f l on ! gr\nd4 ,due to ! motion ( ! %utt] ! end ( ! exposure occurs at a "t l_/v aft] ! />t4 ,9 ?is "t ! plane has mov$ a di/ance ,v l_/v2 h5ce ! po9t photograph$ at ! end ( ! %utt] travel is ,vl_/v )9 or beyond ! orig9al space cov]$ by ! plate1 dep5d+ on ! direction ( motion ( ! curta94 ,! di/ortion1 ,d1 is giv5 by ! ratio ( ?is di/ance to ! l5g? correspond+ to ! normal /ation>y field ( view3 ,v_/v l ,,vf ,d ---------------------- -------- ,a_/,f l v,a ,:5 ,v #bjj kilomet]s p] h\r1 v #ajj c5timet]s p] second1 ,f #ej c5timet]s1 ,a #cjjj met]s1 we h-- #bj1jjj1jjj #ej #a ,d ---------------------------------------- approximately ------ #cfjj #ajj #cjj1jjj #ajj ,or if ! actual di/ance error on ! gr\nd is desir$1 ,vl -------- #aj4h met]s v ,z a p]c5tage error ?is "o p] c5t4 is small comp>$ ) o!r unc]ta9ties1 su* z film %r9kage or ! error ( level ( ! cam]a4 ,z an absolute error 9 survey+1 ?irty feet is1 ( c\rse1 excessive4 ,! di/ortion is dim9i%$ = any specifi$ %utt] spe$ by mak+ ! spe$ ( travel ( ! curta9 z l>ge z possible & by correspond+ly increas+ ! ap]ture4 ,9 connection ) film cam]as1 ano!r solution :i* has be5 sugge/$ is to move ! film cont9u\sly dur+ ! exposure 9 ! direction ( ! plane's motion4 ,! requisite spe$ ( ! film v' to elim9ate di/ortion is giv5 by ! relation3 v' ,f -------- ------ ,v ,a ,= ! values ( ,v1 ,f1 & ,a us$ above1 v' 4#ib c5timet]s p] second4 ,?is spe$ is cle>ly t :i* holds ! image /ation>y on ! film--a fact :i* sugge/s ano!r object = su* movem5t1 namely1 to p]mit ( long] exposures4 ,! effect ( focal plane di/ortion may be av]ag$ out 9 ! mak+ ( /rip maps1 if ! %utt] is con/ruct$ s z to move 9 opposite directions on successive exposures4 ,! fir/ picture w be magnifi$1 ! second compress$1 & s on1 b a /rip =m$ ( accurately juxtapos$ pictures w be sub/antially accurate 9 ov]-all l5g?4 ,su* a %utt] is embodi$ 9 "o ( ! ,g]man film cam]as 7,fig4 #fa74 ,di/ortion ( ! k9d above discuss$ is abs5t ) betwe5-!-l5s %utt]s1 :i* may conceivably be improv$ 9 effici5cy & 9 feasible size4 ,if s !y w\ld m]it s]i\s consid]ation = a]ial mapp+4 ,me?ods & ,app>atus = ,te/+ ,%utt] ,p]=mance4--,) a focal-plane %utt] ! desirable qualities 9 p]=mance are ?ree 9 numb]3 7#a7 ,adequate spe$ range1 :i* may be tak5 z f #a_/ej to #a_/ejj second = a]ial "w1 7#b7 good effici5cy1 :i* has already be5 treat$1 & 7#c7 uni=mity ( spe$ dur+ its travel across ! plate4 ,be=e ! adv5t ( a]ial photography little att5tion 0 paid to spe$ uni=mity1 diff]5ces ( #ej p] c5t4 9 initial & f9al spe$ be+ common 9 focal-plane %utt]s1 & b little notic$ 9 ord9>y l&scape "w because ( ! natural v>iation ( brightness f sky to gr\nd4 ,9 ! mak+ ( a]ial mosaic maps ! non-uni=mity ( d5sity across ! plate results 9 a mo/ (f5sive s]ies ( abrupt *anges ( tone at ! junction po9ts ( ! successive pr9ts 7,fig4 #adj71 an effect :i* mu/ be m9imiz$ by manipulation ( ! pr9t+ light4 ,in/rum5ts = te/+ ! spe$ & uni=mity ( action ( focal-plane %utt]s are an ess5tial "p ( any laboratory = develop+ or te/+ photographic app>atus & "s simple device = sett+ & *eck+ %utt] spe$ %\ld be available 9 ! field4 ,e su* spe$ te/] mu/ conta9 "s =m ( "t c\nt+ elem5t--p5dulum1 tun+ =k or clock-"w4 ,elaborate %utt] te/]s1 suitable = det]m9+ all ! *>act]i/ics ( all types ( %utt]1 h be5 develop$ & us$ 9 c]ta9 ( ! photographic rese>* laboratories4 ,= ! /udy & sett+ ( focal-plane %utt]s 7^: effici5cy ne$ n be measur$1 z x c be simply calculat$ f l9e> dim5sions71 ! foll[+ simple k9ds ( app>atus are adequate3 ,illu/ration3 ,,fig4 #bc4--;,app>atus = te/+ focal plane %utt] spe$ ?r\gh\t ! travel ( ! curta94 ,clock dial type ( %utt] te/]4 ,?is consi/s ess5tially ( a black clock dial c>ry+ a :ite po9t] :i* makes its complete revolution 9 "o second or less4 ,if ?is dial is photograph$ by ! cam]a "u te/1 ! wid? ( ! sector trac$ dur+ ! exposure by ! mov+ po9t] %[s ! "t int]val4 ,if ! dial is photograph$ at sev]al po9ts on ! plate--beg9n+1 middle & end ( ! %utt] travel--! complete *>act]i/ics ( ! %utt] c be det]m9$4 ,int]rupt$ light type ( %utt] te/]4 ,= ! /udy ( uni=mity ( %utt] action alone ! app>atus %[n 9 ,fig4 #bc may be employ$4 ,a is a high int5sity light s\rce1 su* z an arc or a gas fill$ tung/5 lamp4 ,l is a convex l5s1 focuss+ an image ( ! light s\rce on a small ap]ture 9 ! scre5 ,e4 ,d is a sector disc :i*1 driv5 by ! motor ,m1 int]rupts ! transmitt$ light ) a frequ5cy det]m9$ by ! numb] ( op5+s ( ! sector & by ! spe$ ( rotation1 :i* mu/ be measur$ by a ta*omet]4 ,! light div]g+ f ! ap]ture 9 ,e falls ^u ! %utt] ,s1 :i* = ?is te/ is r$uc$ to a n>r[ slit ( "o millimet] or less4 ,pass+ ?r\gh ! %utt] op5+ ! light falls ^u ! photographic plate ,p4 ,! pr9ciple is simple3 ,if ! light is un9t]rupt$1 ! plate ,p is expos$ at all po9ts2 due to ! int]ruptions1 a s]ies ( p>allel l9es ( photographic action result1 & _! di/ance ap>t gives a measure ( ! spe$ ( ! %utt] at any *os5 po9t 9 its travel4 ,a p]=mance curve ( ! ,fr5* ,klopcic %utt] is %[n 9 ,fig4 #bd4 ,! v>iation 9 spe$ lies ov] a range ( two to "o4 ,s s]i\s is ?is defect 9 ^! %utt]s t diaframs are sometimes ins]t$ 9 ! ,fr5* cam]as to cut (f "p ( ! light f ! l5s on ! mo/ expos$ end ( ! plate4 ,?is exp$i5t produces uni=mity ( photographic action1 b does n ov]come ! movem5t ( ! image1 :i* is "o ( ! *ief faults ( excessive exposure4 ,illu/ration3 ,,fig4 #bd4--,p]=mance ( ,klopcic %utt]4 ,illu/ration3 ,,fig4 #be4--,optical sy/em ( %utt] te/] = ,air ,s]vice1 ,u4 ,s4 ,army4 ,a m complete app>atus1 adapt$ bo? to absolute spe$ det]m9ations & to ! /udy ( uni=mity ( action1 is t work$ out & us$ 9 ! ,unit$ ,/ates ,air ,s]vice 7,fig4 #be74 ,at ,a is a high int5sity light s\rce1 an image ( :i* is focuss$ by ! l5s ,l#a ^u a slit ,e1 9 front ( :i* /&s a tun+ =k ,t1 ( p]iod #ajbd or #bjdh p] second4 ,! light div]g+ f ! slit is receiv$ by a second l5s1 ,l#b :i* is arrang$ ei!r to focus ! slit image ^u ! %utt] curta9 or to r5d] ! rays p>allel1 s t an entire cam]a may be ins]t$4 ,9 ! latt] case ! cam]a l5s ,l#c s]ves to focus ! slit image on ! curta9 ,c4 ,aft] pass+ ?r\gh ! curta9 ap]ture ! light is focuss$ by ! l5s ,l#d on ! rotatable drum ,d1 :i* c>ries a /rip ( s5sitive film4 ,! op]ation ( te/+ a %utt] consi/s 9 focuss+ ! slit image on ! portion ( ! %utt] ^: p]=mance is requir$1 /rik+ ! tun+ =k to set x vibrat+1 rotat+ ! drum rapidly & sett+ (f ! %utt]4 ,!re is ?us obta9$ on ! s5sitive film an expos$ /rip resembl+ 9 appe>ance ! edge ( a saw1 ! numb] ( tee? %[+ ! "t int]val 9 vibrations ( ! tun+ =k4 ,?ree exposures usually give all ! po9ts necess>y = a practical k ( ! %utt]'s uni=mity ( action4 ,a po9t ( "s importance1 le>n$ f num]\s %utt] te/s1 is t a focal-plane %utt] %\ld be te/$ 9 ! position 9 :i* x is to be us$4 ,a]ial cam]a %utt]s %\ld be te/$ 9 ! horizontal position4 ,types ( ,focal-plane ,%utt]s4--,a v>iety ( means h be5 utiliz$ = secur+ ! necess>y v>iation 9 spe$ 9 focal-plane %utt]s4 ,_! success is to be measur$ by ! actual spe$ range & by ! uni=mity ( spe$ atta9$4 ,9 a]ial cam]as at pres5t 9 use we f9d v>iable t5sion ( ! curta9 spr+1 ! ap]ture be+ fix$2 v>iable op5+ ) fix$ t5sion2 multiple curta9 op5+s ) fix$ spr+ t5sion2 & comb9ations ( two or all ( ^! me?ods ( spe$ control4 ,! problem ( cov]+ ! ap]ture dur+ ! op]ation ( w9d+ up or sett+ ! %utt] has l$ to fur!r elaborations ( %utt] me*anism4 ,^! take ! =m ( l5s or %utt] flaps1 auxili>y curta9s1 & %utt]s ( ! self-capp+ type4 ,%utt]s embody+ all ^! features are briefly describ$ bel[4 ,repres5tative ,%utt]s4--,! ,folm] v>iable t5sion %utt] is us$ on ! ,unit$ ,/ates ,air ,s]vice h&-held & h&-op]at$ plate cam]a & on "s ( ! film cam]as4 ,x consi/s ( a fix$ ap]ture curta9 w\nd on a curta9 roll] 9 :i* ! spr+ c be set to v>i\s t5sions1 numb]$ #a to #aj4 ,! range ( spe$s atta9able is at be/ ab\t ?ree to "o1 or f #a_/ajj to #a_/cjj second1 consid]ably %ort] ?an ! range indicat$ z desirable4 ,its uni=mity ( travel is v>iable ) ! t5sion1 z %[n by repres5tative p]=mance curves 9 ,fig4 #cj4 ,lack+ any self-capp+ feature ! %utt] is provid$ ei!r ) an auxili>y curta91 or 9 ! h&-held cam]a ) flaps 9 front ( ! l5s1 op5$ by ! expos+ lev] be=e ! curta9 is releas$ 7,fig4 #ci74 ,?is %utt] is made a removable unit 9 ! #ah #bd c5timet] h&-op]at$ cam]a1 b is built into ! h&-held & film cam]as4 ,illu/ration3 ,,fig4 #bf4--,removable f\r-slit %utt] ( ,g]man 7,ica7 cam]a1 %[+ flaps4 ,! ,ica %utt] us$ on ! /&>d ,g]man a]ial cam]as is a good example ( ! multiple slit curta9 7,fig4 #bf74 ,f\r fix$ ap]ture slits are provid$1 ) a s+le t5sion1 ! op5+s r\ghly 9 ! ratio #a1 1 1 1 :i* :5 ! spr+ t5sion is prop]ly adju/$ give exposures ( #a_/ij1 #a_/ahj1 #a_/cge1 #a_/gej second4 ,to pass f "o exposure "t to ano!r ! sett+ mill$ head is w\nd up to successively high] /eps or else expos$ "o or m times )\t resett+1 dep5d+ on ! direction x is desir$ to g4 ,capp+ dur+ sett+1 or dur+ exposure1 9 ord] to *ange ! op5+1 is provid$ = by a pair ( flaps on ! %utt] unit1 :i* op5 into ! cam]a body4 ,! me*anical "w on ^! %utt]s is ( excell5t quality1 ! curta9 runn+ ) exceptional smoo?ness4 ,provision is made = adju/+ ! t5sion until ! m>k$ spe$s are atta9$2 ?is is presumably done 9 a repair laboratory to :i* ! %utt] only ne$ be s5t1 z x is a removable unit4 ,te/s made on "o ( ^! %utt]s w\nd to its highe/ t5sion are %[n 9 ,fig4 #cj4 ,! m>k$ spe$s are n atta9$1 & !re is consid]able lack ( uni=mity f />t to f9i% ( ! travel4 ,l cam]a v>iable-ap]ture %utt]4 ,! %utt] ( ! ,l type cam]a 7,fig4 #bg7 is repres5tative ( "o ( ! mo/ primitive me?ods ( v>y+ ap]ture4 ,! two jaws ( ! slit are held toge!r by a long cord pass+ completely ar\nd ! ap]ture1 fa/5$ p]man5tly at "o end & atta*$ at its o!r end by a slid+ clasp or saddle4 ,z ?is saddle is =c$ 9 "o direction ! slit is clos$1 9 ! opposite direction ! cord becomes slack1 & aft] ! %utt] is releas$ once or twice ! slit assumes a wid] op5+4 ,a *ronic tr\ble is ! break+ ( ! cords4 ,its op5+ c be *ang$ only aft] ! plate magaz9e is remov$4 ,illu/ration3 ,,fig4 #bg4--8,l0 type cam]a %[+ op5 negative magaz9es & %utt] me*anism4 ,u4 ,s4 ,air ,s]vice v>iable-ap]ture %utt]4 ,?is %utt] is incorporat$ 9 ! ,am]ican de,ram & 9 o!r late ,am]ican cam]as 7,fig4 #bh74 ,its *>act]i/ic feature is ! introduction ( an idl]1 ^: di/ance f ! ma9 curta9 roll] c be v>i$4 ,tapes :]eby ! foll[+ curta9 is atta*$ to ! spr+ roll] pass ov] ?is idl]1 & by *ang+ its position ! ap]ture or di/ance betwe5 ! two curta9 elem5ts is alt]$ ov] a l>ge range4 ,te/s ( ?is %utt] are %[n 9 ,fig4 #cj4 ,a spe$ ( #a_/ej second is provid$ = by a slit wid? ( five c5timet]s1 & ! highe/ spe$ is fix$ only by ! practical limit ( approa* ( ! jaws4 ,exp]im5t %[s great uni=mity ( rate ( travel to be atta9able by comb9+ c>eful *oice ( spr+ l5g? & t5sion ) good workman%ip 9 ! me*anical features4 ,v>iable-ap]ture fix$-t5sion %utt]s h a def9ite advantage ov] ! v>iable-t5sion type 9 t !y c utilize = all spe$s t t5sion :i* gives uni=m action4 ,! capp+ feature ( ?is %utt] is provid$ 9 ! ,am]ican de,ram by flaps1 9 ! automatic film cam]a by an auxili>y curta94 ,! %utt] is removable 9 ! de,ram1 b built into ! o!r cam]a4 ,illu/ration3 ,,fig4 #bh4--,v>iable ap]ture curta9 develop$ 9 ,u4 ,s4 ,air ,s]vice1 & us$ 9 ,am]ican de,ram1 & 8,k0 type automatic film cam]as4 ,! ,klopcic v>iable-t5sion1 v>iable-ap]ture1 self-capp+ %utt] is an example ( an attempt to meet all %utt] requirem5ts ) an entirely self-conta9$ me*anism4 ,x is %[n diagrammatically 9 ,fig4 #bi4 ,tapes ,g#a1 ,g#b are us$ to connect ! foll[+ curta9 ,b directly to ! spr+ roll] ,t1 at a fix$ di/ance1 :ile ! lead+ curta91 ,a1 may be slid along ! tapes by small friction buckles1 ,c#a1 ,c#b1 auxili>y spr+s ,r#a1 ,r#b s]v+ to keep x taut 9 any position4 ,:5 ! %utt] is be+ set ! buckles are arre/$ aga9/ /ops :ile ! w9d+-up cont9ues = :at is to be ! foll[+ half ( ! curta9 9 expos+4 ,:5 releas$ ! curta9 moves across ) an ap]ture fix$ by ! po9t ( sett+ ( ! buckle /ops4 ,at ! end ( ! travel ! buckles are arre/$ by o!r /ops1 :ile ! foll[+ portion ( ! curta9 cont9ues its travel to ! end4 ,on re-w9d+1 !re=e1 ! ap]ture is clos$4 ,v>iable t5sion z well z v>iable ap]ture is provid$1 al?\gh little us$4 ,9 ! ,fr5* cam]as a l5s flap is also ins]t$ beh9d ! l5s1 b ?is is n ne$$ if ! self-capp+ feature functions prop]ly4 ,on ! h& cam]as ?is flap is said to be necess>y 9 ord] to prev5t a curi\s k9d ( accid5t3 if ! cam]a is held on ! knee1 po9t+ upw>d1 an image ( ! sun may be =m$ on ! curta9 & burn a hole ?r\gh x4 ,illu/ration3 ,,fig4 #bi4--,me*anism ( ,klopcic v>iable ap]ture self-capp+ %utt]4 ,! p]=mance ( ! ,fr5* %utt] 9 respect to uni=mity has already be5 %[n 9 ,fig4 #bd4 ,x leaves v mu* to be desir$4 ,besides non-uni=mity ( action dur+ its travel x exhibits ano!r common defect ( v>iable-t5sion %utt]s1 namely1 ! curta9 mu/ be releas$ sev]al times aft] a *ange ( t5sion be=e ! new spe$ is e/abli%$ 7,fig4 #cj1 t5sions #e & #e74 ,illu/ration3 ,,fig4 #cj4--,p]=mances ( v>i\s %utt]s us$ on a]ial cam]as4 ,spe$s express$ 9 reciprocals ( fractional p>ts ( "o second4 ,! ,fr5* %utt] z made = ! de,maria cam]as is a removable unit4 ,! small size 7#ac #ah cm47 sets by ! /raight pull ( a project+ p91 ! l>g] 7#ah #bd cm47 by w9d+ up a mill$ head4 ,! =m] is ! m conv5i5t motion = an a]ial cam]a4 ,c>e mu/ be tak5 ) ei!r type t ! motion ( sett+ is n /opp$ :5 ! fir/ resi/ance is enc\nt]$2 ?is occurs :5 ! tape buckles /rike _! /op & ! slit beg9s to op54 ,,*apt] ,,vi ,,plate-,,hold]s ,,& ,,magaz9es ,9 ! e>li] days ( airplane photography ! ord9>y plate-hold] or d\ble d>k slide 0 us$ to "s ext5t1 b x is ill-suit$ to ! purpose because ( ! consid]able "t & att5tion requir$ = its op]ation4 ,x has nev]!less ! m]it ( add+ little to ! l5g? ( ! cam]a1 & x works 9 any position4 ,= ^! reasons x has rema9$ 9 occasional use = ! tak+ ( oblique views ) long focus cam]as 9 a cramp$ fuselage4 ,next 9 ord] ( progress rank ! simple box magaz9es1 = hold+ a doz51 eighte5 or tw5ty-f\r plates1 z us$ 9 ! ,engli% ,c1 ,e1 & ,l type cam]as4 ,^! are little m ?an boxes ) slid+ lids :i* :5 op5 p]mit ! introduction or removal ( ! plates4 ,figs4 #de & #df illu/rate ! magaz9e ( ?is type z made = ! ,engli% ,c & ,e cam]as4 ,x is con/ruct$ ( wood1 groov$ to fit tracks on ! cam]a1 & is furni%$ ) a slid+ door or lid h+$ 9 ! middle to fold d[n out ( ! way :5 op54 ,! eighte5 plates are c>ri$ 9 metal %ea?s1 bo? to provide opaque scre5s betwe5 !m1 & to protect !m f injury 9 ! me*anism ( ! cam]a4 ,fig4 #bg %[s ! all-metal magaz9e made = ! ,am]ican model ,l cam]a4 ,?is diff]s f ! ,engli% 9 mat]ial ( con/ruction1 plate capacity 7#bd in/ead ( #ah7 & mann] ( op]at+ ! slide1 :i* is built up ( ?ree ?icknesses ( phosphor bronze & draws out ?r\gh metal guides b5t into semicircul> =m4 ,a snap cat* holds ?is slide at ei!r end ( its travel4 ,! lea!r /rap introduc$ 9 ! ,am]ican model = c>ry+ & h&l+ is a di/9ct improvem5t4 ,^! magaz9es conta9 no spr+s or o!r me*anism1 z ! cam]as ) :i* !y are us$ dep5d ^u ! action ( gravity = empty+ ! upp] 7fe$+7 magaz9e1 & fill+ ! l[] 7receiv+7 "o4 ,illu/ration3 ,,fig4 #ca4--;,a]ial h& cam]a 7,u4 ,s4 type ,a-#b74 ,next 9 ord] ( complexity may be rank$ ! bag magaz9e 7,figs4 #ca & #dd74 ,9 ?is ! expos$ plate is pull$ out ( ! magaz9e prop] by a metal slide or rod into a lea!r bag4 ,! rod is !n pu%$ back1 ! plate 9 its metal %ea? is grasp$ ?r\gh ! lea!r bag1 lift$ to ! back ( ! magaz9e1 & =c$ 9 beh9d ! o!r plates4 ,! numb] ( plates expos$ is indicat$ ei!r by numb]s on ! backs ( ! %ea?s1 visible ?r\gh a r$ glaz$ op5+ 9 ! back1 or else by a c\nt] actuat$ by ! metal slide rod4 ,usually twelve are c>ri$ 9 a magaz9e4 ,= a]ial "w ! common design ( ?is magaz9e z us$ = gr\nd "w mu/ be modifi$ by provid+ extra l>ge easily grasp$ hooks bo? on ! draw rod & on ! d>k slide1 :i* mu/ be drawn be=e mak+ ! fir/ exposure & replac$ aft] ! la/4 ,! small r+s & grips ( ! /&>d comm]cial magaz9e are almo/ impossible to h&le ?r\gh heavy gloves4 ,! next type ( magaz9e is repres5t$ by ?ree designs1 ! ,gaumont & de,maria1 us$ v g5]ally by ! ,fr5* dur+ ! w>1 & ! ,ernemann1 us$ almo/ univ]sally 9 ! ,g]man air s]vice 7,figs4 #cb1 #dj & #db74 ,9 all ( ^! ! op]ation ( plate *ang+ is ! same3 ! end ( ! magaz9e is pull$ out & ?ru/ back1 a m simple op]ation ?an ! bag manipulation j describ$4 ,! int]nal work+s are diff]5t accord+ to size4 ,9 ! small] ,fr5* magaz9es 7#ac #ah cm47 ! cam]a is fir/ po9t$ upw>d1 all ! plates are drawn out except ! "o to be *ang$1 & ?is1 ) ! aid ( spr+s1 drops to ! bottom1 aft] :i* ! o!r plates pu% back ov] x4 ,! plates pull out 9 ! direction ( _! long dim5sion4 ,9 ! l>g] ,fr5* magaz9e 7#ah #bd cm47 only ! expos$ plate pulls out4 ,! pull is 9 ! direction ( ! %ort] dim5sion ( ! plate1 :i* is lift$ up by heavy spr+s & slides back ov] ! top ( ! pile4 ,9 ! ,ernemann magaz9e only six plates are c>ri$1 :i* !re is good reason to believe repres5t ! maximum feasible numb]1 judg+ by ! reports ( jambs & breakages 9 ! twelve-plate ,fr5* magaz9es4 ,9 all ( ^! magaz9es lam9at$ wood slides pull out & 9 at ea* op]ation1 & :ile satisfactory if made & op]at$ 9 "o climate1 exp]i5ce indicates t if made 9 ,am]ica & s5t abroad swell+ ( ! wood may be expect$ to prev5t _! successful op]ation4 ,illu/ration3 ,,fig4 #cb4--,v>i\s plate magaz9es us$ on a]ial cam]as4 ,alt]native =ms ( magaz9e1 some:at m practical f ! /&po9t ( manufacture & export1 are sev]al designs embody+ two comp>tm5ts 7,fig4 #cb74 ,9 ! mo/ simple ( ^! ! plates are mov$1 imm$iately be=e or aft] expos+1 f ! unexpos$ to ! expos$ side4 ,illu/rative ( ?is type are ! ,folm] designs1 9 :i* ! to-&-fro motion is imp>t$ by a rack ge>$ to a p9ion actuat$ ei!r by a lev]1 9 ! h& cam]a1 or by ! p[] drive1 9 ! automatic design 7,figs4 #cc & #ec74 ,ano!r illu/ration is af=d$ by ! ,pis]9i & ,mond9i magaz9e1 9 :i* ! op]ation ( *ang+ is p]=m$ by a back-&-=? motion ( a h&-grip1 :i* also sets ! cam]a %utt] 7,fig4 #dg74 ,illu/ration3 ,,fig4 #cc4--,u4 ,s4 ,air ,s]vice h& cam]a1 ) two-comp>tm5t magaz9e4 ,illu/ration3 ,,fig4 #cd4--;,film type h& cam]a4 ,9 ^! magaz9es ! c5t] ( gravity *anges z ! expos$ plates are mov$ ov]1 & only half ! inside space is occupi$ ) plates4 ,^! objections are ov]come 9 ! ,*assel =m1 :]e bo? comp>tm5ts are always full4 ,transf] ( ! bottom expos$ plate f "o comp>tm5t to ! o!r is comp5sat$ = by ! simultane\s %ift ( ! top plate 9 ! receiv+ comp>tm5t1 to ! fe$+ side4 ,9 a modification ( ?is idea by ,ruttan ! expos+ position is :5 ! plates are half-way ?r\gh ! %ift+ process1 :]eby ! magaz9e may be symmetrically m\nt$ on ! cam]a body4 ,illu/ration3 ,,fig4 #ce4--;,app>atus = /raight5+ plate %ea?s4 ,o!r m complicat$ magaz9es h be5 design$1 "s ( :i* are %[n 9 ! diagrammatic ensembles ( ,figs4 #cb & #dh4 ,9 ! ,jacquel91 ! ma9 body ( plates is rais$ :ile ! bottom 7expos$7 plate is fold$ aga9/ ! side4 ,! ma9 body ( plates !n drops back to place1 ! expos$ plate is c>ri$ on upw>d & folds d[n on ! back ( ! pile4 ,! ,belli5i magaz9e sy/em uses ?ree1 a c5tral fe$+ "o & two bel[ = receiv+1 "o on ea* side ( ! cam]a body4 ,^! 7 made solely = atta*m5t to captur$ ,g]man cam]as4 ,9 ! ,f\rnieux magaz9e ! plates are c>ri$ 9 an int]ior rotat+ box4 ,! plate to be expos$ is dropp$ (f ! front ( ! pile1 d[n to ! focal plane1 & aft] exposure is pick$ up & plac$ at ! back ( ! pile1 :i* has turn$ ov] 9 ! mean:ile4 ,! de,ram rotat+ magaz9e is describ$ 9 connection ) ! cam]a ( :i* x is an ess5tial "p 7,fig4 #eb74 ,illu/ration3 ,,fig4 #cf4--,tra9+ plane equipp$ = photography1 %[+ 8,l0 cam]a 9 floor m\nt & magaz9e rack =w>d ( ! obs]v]4 ,= ! protection ( ! plates dur+ _! manipulation1 & 9 ! cam]a1 all plate magaz9es ?us f> develop$ c>ry !m 9 ?9 metal %ea?s4 ,^! add greatly bo? to ! weight & to ! "t necess>y to h&le ! plates1 b no means h z yet be5 f\nd = disp5s+ ) !m4 ,fig4 #ce %[s a repres5tative %ea? or septum1 z us$ 9 ! ,l cam]a4 ,on ?ree sides ! edge is b5t up & turn$ ov]1 =m+ a l$ge = ! plate to press aga9/4 ,! f\r? side is left op5 = ins]t+ ! plate1 :i* is !n held 9 by a small upw>d project+ lip1 & kept close aga9/ ! l$ges by n>r[ spr+s at ! sides4 ,to ins]t or remove ! plate ! project+ lip is depress$1 ei!r by spr++ ! %ea? by pressure f ! sides or by us+ an appropriate tool4 ,c>e ( %ea?s4 ,unless sy/ematically tak5 c>e (1 plate %ea?s become b5t or d5t$4 ,!y are !n a m5ace to cam]a op]ation1 cat*+ or jamm+ 9 ! plate *ang+ process1 break+ plates & damag+ cam]a me*anisms4 ,9 ord] to ma9ta9 !m flat & true1 /eel =ms are necess>y on :i* ! %ea?s may be hamm]$ to %ape ) a mallet 7,fig4 #ce74 ,magaz9e racks4 ,reconnaissance & mapp+ call = a numb] ( exposures mu* great] ?an ! capacity ( "o #ab1 #ah1 or #bd plate magaz9e4 ,additional magaz9es mu/ !re=e be c>ri$4 ,^! %\ld be 9 racks conv5i5t to ! obs]v] 7,fig4 #cf71 securely held yet capable ( quick removal & ins]tion4 ,9 ! rack design$ to c>ry two ( ! metal magaz9es = ! ,am]ican ,l ,cam]a1 ! magaz9es slide into loose grooves =m$ by a metal lip4 ,!y are prev5t$ f slipp+ out by a spr+ cat*1 pa/ :i* !y slide :5 ins]t$ b :i* is in/antly ?r[n aside by pressure ( ! ?umb z ! h& grasps ! magaz9e h&le = removal4 ,,*apt] ,,vii ,,h&-,,held ,,cam]as ,,= ,,a]ial ,,"w ,field ( ,use4--,! fir/ cam]as to be us$ = a]ial photography 7 h&-held ones ( ord9>y comm]cial types4 ,inde$ ! idea is /ill preval5t t to obta9 a]ial photographs ! aviator m]ely leans ov] ! side ) ! fold+ pocket cam]a ( ! dep>tm5t /ore %[ w9d[ & presses ! button4 ,b ! ,great ,w> _h n la/$ long be=e ! ord9>y bell[s focuss+ h& cam]a 0 replac$ by ! rigid-body fix$-focus =m1 equipp$ ) h&les or pi/ol grip = bett] hold+ 9 ! high w9d made by ! plane's progress ?r\gh ! air4 ,ev5 ?is phase ( a]ial photography 0 comp>atively %ort-liv$4 ,! ne$ = cam]as ( great focal l5g?1 & ! ne$ = app>atus dem&+ ! m9imum ( ! pilot's or obs]v]'s att5tion1 bo? t5d$ to relegate h&-held cam]as to second place1 s t !y 7 comp>atively little us$ 9 ! lat] p]iods ( ! w>4 ,yet = c]ta9 purposes !y h great value4 ,!y c be us$ 9 any plane = tak+ oblique views1 & = tak+ v]ticals1 9 any plane 9 :i* an op5+ = unob/ruct$ view c be made 9 ! floor ( ! obs]v]'s cockpit4 ,!y c be quickly po9t$ 9 any desir$ direction1 ?us r$uc+ to a m9imum ! necess>y maneuv]+ ( ! plane1 a real advantage :5 "u attack by 8,ar*ies0 or 9 work+ "u adv]se wea!r conditions4 ,= peace-"t mapp+ "w ! h&-held cam]a1 :5 equipp$ ) _s-levels on top1 & :5 work$ by a skilful op]ator1 possesses "s advantages ov] any?+ %ort ( an automatically /abiliz$ cam]a4 ,= exp]im5tal te/+ ( plates1 filt]s & v>i\s accessories1 ! ready accessibility ( all its p>ts makes ! h&-held cam]a ! easie/ & mo/ satisfactory ( in/rum5ts4 ,! limitations ( ! h&-held cam]a lie 9 its necess>y re/riction to small plate sizes & %ort focal l5g?s1 & 9 ! fact t x mu/ occupy ! entire att5tion ( ! obs]v] :ile pictures are be+ tak5--! latt] a s]i\s objection only 9 w>-"t4 ,ess5tial ,*>act]i/ics4--,9 addition to ! g5]al requirem5ts z to l5s1 %utt] & magaz9e1 common to all a]ial cam]as1 ! h& cam]a mu/ meet ! special problems introduc$ by hold+ 9 ! h&s1 especially ov] ! top ( ! plane's cockpit4 ,an exceptionally good sy/em ( h&les or grips mu/ be provid$ :]eby ! cam]a c be po9t$ :5 pictures are tak51 & held :ile plates are be+ *ang$ & ! %utt] set4 ,! weight & balance ( ! cam]a mu/ be correct )9 n>r[ limits2 ! w9d resi/ance mu/ be z small z possible2 ! %utt] release mu/ be arrang$ s z to give no j]k or tilt to ! cam]a 9 expos+4 ,z to ! me?od ( hold+ ! cam]a1 a favorite at fir/ among milit>y m5 0 ! pi/ol grip1 ) a trigg] %utt] release 7,fig4 #cg74 ,because ( ! size & weight ( ! cam]a ! pi/ol grip alone 0 an inadequate means ( support & additional h&les on ! side or bottom _h to be provid$ = ! left h&4 ,small 7#h #ab cm47 pi/ol grip cam]as 7 us$ to "s ext5t by ! ,g]mans 7,fig4 #db71 & a numb] ( #d #e in* exp]im5tal cam]as ( ?is type 7 built = ! ,am]ican ,air ,s]vice 7,fig4 #cg74 ,b ! grasp obta9$ ) su* a design is n s good z is obta9$ ) h&les on ea* side or ) flat /raps to g ov] ! h&s4 ,! cam]a balances be/ ) ! h&les 9 ! plane ( ! c5t] ( gravity4 ,z to weight1 no set rules are laid d[n1 b exp]i5ce has %[n t a fairly heavy cam]a--z heavy z is conv5i5t to h&le--w hold /eadi] ?an a light "o4 ,! ,am]ican #d #e in* cam]as describ$ bel[ weigh ) _! magaz9es 9 ! neighborhood ( twelve p\nds4 ,illu/ration3 ,,fig4 #cg4--,pi/ol-grip a]ial h& cam]a4 ,repres5tative ,types ( ,h&-held ,cam]as4--,fr5* & ,g]man h&-held cam]as are ess5tially small] editions ( _! /&>d long-focus cam]as1 & a description ( !m w apply to a consid]able ext5t to ! l>ge cam]as to be discuss$ 9 a lat] *apt]4 ,! ,engli% & ,am]ican h&-held cam]as are g5]ally q diff]5t 9 type f ! l>ge ones1 :i* are us$ atta*$ to ! plane4 ,illu/ration3 ,,fig4 #ch4--;,diagram ( ,fr5* 7de,maria7 #bf cm4 focus h& cam]a1 us+ #ac #ah cm4 plates4 ,! ,fr5* h&-held cam]a uses #ac #ah c5timet] plates1 c>ri$ 9 a de,maria magaz9e1 & has a l5s ( #bf c5timet]s focus4 ,! %utt] is ! ,klopcic self-capp+ type already describ$1 & is removable4 ,! cam]a body1 built ( %eet alum9um1 takes a pyramidal %ape4 ,9 ,fig4 #ch1 ,a is ! %utt] release & ,b ! rectangul> sight1 ( :i* ,c is ! re> or eye sight4 ,! complete sight may be plac$ ei!r on ! top or on ! bottom ( ! cam]a4 ,at ,d are ! h&les1 slop+ =w>d f top to bottom2 ,e is a cat* = hold+ ! magaz9e2 ,f is a door = rea*+ ! back ( ! l5s & ! l5s flap2 ,g is a snap clasp = hold+ ! front door ( ! cam]a clos$2 ,h is a r+ = atta*+ a /rap to g ar\nd ! obs]v]'s neck2 ,i is ! lev] :i* op5s ! flap beh9d ! l5s & releases ! focal-plane %utt]2 ,j is a snap cat* = hold+ ! front door ( ! cam]a op54 ,! op]ations ) ?is cam]a are ?ree 9 numb]4 ,/>t+ imm$iately aft] ! exposure1 ! cam]a is po9t$ l5s upw>d & ! plate *ang$ by pull+ ! inn] body ( ! magaz9e out & !n 92 next ! %utt] is set2 !n ! cam]a is po9t$1 & f9ally expos$ by a g5tle pull on ! expos+ lev]4 ,! ,engli% h&-held cam]a 7,fig4 #ahf74 ,?is diff]s f ! ,fr5* 9 ! size ( plate 7#d #e in*71 9 ! %ape ( ! cam]a body1 :i* is circul>1 & 9 ! type ( %utt]1 :i* is fix$-t5sion v>iable-op5+4 ,9 ! long] focus cam]a 7#aj to #ab in*7 ! %utt] is self-capp+1 & ! ap]ture is controll$ by a ?umb-screw at ! side4 ,9 ! small] 7#f in*7 a l5s flap is provid$ 9 front ( ! l5s & ! %utt] ap]ture is v>i$ by a slid+ saddle & cord4 ,! h&les ( ! cam]a are plac$ v]tical1 in/ead ( slop+ z 9 ! ,fr5*4 ,! %utt] is releas$ by a ?umb-actuat$ lev]4 ,d\ble d>k slides are us$1 z ! multiple plate magaz9e has n f\nd favor 9 ! ,engli% s]vice4 ,! ,g]man h&-held cam]a 7,fig4 #db74 ,! ,g]man h&-held cam]a is1 l _! :ole s]ies1 built ( canvas-cov]$ wood1 ! body hav+ an octagonal cross-section4 ,x is equipp$ ) ! ,ica %utt] & uses ! ,ernemann six plate 7#ac #ah cm47 magaz9e4 ,! excell5t sy/em ( grips by :i* ! cam]a is held & po9t$ is an especially comm5dable feature4 ,on ! "r-h& side is a h&le simil> to ! ,fr5* type1 b c>efully %ap$ to fit ! h&4 ,! left-h& grip consi/s ( a long1 r\nd$ block ( wood runn+ diagonally f top to bottom ( ! side1 ) a deep groove on ! =w>d side = ! f+] tips1 :ile ov] ! h& is /ret*$ a lea!r /rap1 ! :ole aim be+ to provide an absolutely sure & com=table hold on ! cam]a dur+ ! plate *ang+ & %utt] sett+ op]ations4 ,illu/ration3 ,,fig4 #ci4--;,front view ( ,u4 ,s4 a]ial h& cam]a1 %[+ l5s flaps p>tly op51 & details ( tube sight4 ,unit$ ,/ates ,air ,s]vice h& cam]as4 ,! h& cam]a develop$ = ! ,unit$ ,/ates ,air ,s]vice & manufactur$ by ! ,ea/man ,kodak ,co4 is made 9 ?ree models1 us+ ! bag magaz9e1 a two-comp>tm5t magaz9e1 & roll film1 respectively4 ,! %utt] is ( ! fix$ 7"o or two7 ap]ture v>iable t5sion type1 built into ! cam]a4 ,a di/9ctive feature is ! d\ble l5s flap1 9 front ( ! l5s actuat$ by ! ?umb pressure %utt] release 7,fig4 #ci74 ,9 ! bag magaz9e cam]a ! %utt] is set1 z a sep>ate op]ation1 by a w+ h&le1 & a simil> h&le controls ! t5sion adju/m5t4 ,9 ! two-comp>tm5t type 7,fig4 #cc7 ! %utt] w9d-up is ge>$ to ! plate *ang+ lev]1 s t b "o op]ation is necess>y to prep>e ! cam]a = exposure4 ,9 ! film type 7,fig4 #cd7 a s+le lev] motion sets ! %utt] & w9ds up ! film ready = ! next exposure4 ,aft] ! la/ exposure ( all ! film is w\nd backw>d on its own 7fe$+7 roll] be=e remov+ f ! cam]a4 ,! film is held flat by a closely fitt+ metal plate beh9d1 & by guides at ! edges 9 front1 an arrangem5t :i* ) small sizes works fairly well al?\gh ! exquisite %>pness ( focus atta9able ) plates is n to be expect$4 ,! sav+ 9 weight made possible by ! use ( film 9 place ( plates 9 metal %ea?s is ab\t ?ree p\nds p] doz5 exposures4 ,9 all ^! cam]as ! sight--a tube ) front & back cross wires--is plac$ at ! bottom4 ,?is position has be5 f\nd ! mo/ conv5i5t = airplane "w1 z x necessitates ! obs]v] rais+ himself b little above ! cockpit1 a matt] ( prime importance :5 ! trem5d\s drive ( ! w9d is tak5 into acc\nt4 ,,*apt] ,,viii ,,non-,,automatic ,,a]ial ,,plate ,,cam]as ,! ideal ( e milit>y photographic s]vice has be5 an automatic or at lea/ a semi-automatic cam]a1 9 ord] to r$uce ! obs]v]'s "w to a m9imum4 ,yet z a matt] ( fact almo/ all ! a]ial photography ( ! ,great ,w> 0 done ) entirely h&-op]at$ cam]as4 ,! prim>y reason = ?is 0 t no entirely satisfactory automatic cam]as 7 develop$1 cam]as at once simple to in/all & reliable :5 op]at$4 ,ev5 ! propell]-drive semi-automatic ,l type ( ! ,briti% ,air ,s]vice 0 v commonly op]at$ by h&1 = _m ( ! pilots & obs]v]s reg>d$ ! propell] m]ely z ano!r "p to g wrong4 ,any automatic me*anism 9 ! airplane mu/ "w well 9 spite ( vibration1 ?ree dim5sional movem5ts1 & great range ( temp]ature4 ,! requirem5ts 7 well recogniz$ :5 ! w> clos$1 b _h n yet be5 met4 ,c>eful /udy ( ! conditions & ne$s by compet5t design]s ( automatic ma*9]y may be expect$ to result at an e>ly date 9 reliable cam]as ( ! automatic type1 b ! description bel[ ( h&-op]at$ cam]as really cov]s practically all ! cam]as f\nd satisfactory 9 actual w>f>e4 ,g5]al ,*>act]i/ics ( ,h&-op]at$ ,cam]as4--,z di/+ui%$ f ! h&-held cam]as ! l>g] h&-op]at$ cam]as are *>act]iz$ by ! great] focal l5g? ( _! l5ses1 ! size ( plate employ$1 & ! mann] ( hold+--by "s =m ( anti-vibration m\nt+ atta*$ directly to ! fuselage4 ,except = ! e>ly ,engli% ,c & ,e type cam]as :i* call$ = #aj in* l5ses & #d #e in* plates1 ! g5]al practice at ! close ( ! w> by agreem5t betwe5 ! ,fr5*1 ,engli% & ,am]ican ,air ,s]vices1 0 = ! use ( #ah #bd c5timet] plates & = l5ses ) focal l5g?s ( approximately #be1 #ej & #abj c5timet]s4 ,! ,engli% also made use ( a #ad in* 7#ce c5timet]7 l5s1 & nev] made a regul> practice ( any?+ l>g] ?an #ej c5timet]s4 ,! ,g]mans & ,italians re/rict$ !mselves to ! #ac #ah c5timet] size ( plate1 :ile a l5s ( #gj c5timet]s focal l5g? 0 /&>diz$ ) ! ,g]mans1 9 addition to ! #be1 #ej1 & #abj c5timet]4 ,! p>ticul> focal l5g? 0 det]m9$ by ! nature ( ! photographic mission4 ,:]e l>ge areas 7 to be cov]$ at l[ altitudes or )\t ! dem& = exquisite detail1 ! %ort] focus l5ses suffice4 ,! mo/ commonly us$ l5s 9 ! ,fr5* ,s]vice 0 ! #ej c5timet]1 :ile ! #abj 0 employ$ :5 high fly+ 0 necess>y or :5 m9ute detail 0 requir$4 ,z already m5tion$1 ! common practice 0 to keep cam]as ( all focal l5g?s available1 b ! ideal at ! close ( ! w> 0 to h ! cam]a nose & l5s a deta*able unit1 s t any focal l5g? desir$ c\ld be secur$ ) ! same cam]a body4 ,! /&>d ,fr5* cam]a4 ,! h&-held =m ( ,fr5* cam]a has already be5 describ$4 ,! cam]as = l>g] plate sizes & long] focus l5ses diff] only 9 ! addition ( a ,b[d5-wire di/ance release = ! %utt] & 9 ! use ( ! ,gaumont magaz9e :i* op]ates )\t ! necessity ( po9t+ ! expos$ side ( ! magaz9e upw>d4 ,fig4 #dj illu/rates ! #ej c5timet] cam]a1 & ,fig4 #da ! #abj4 ,illu/ration3 ,,fig4 #dj4--ej c5timet] de,maria h& op]at$ cam]a on t5nis ball m\nt+4 ,illu/ration3 ,,fig4 #da4--abj c5timet] de,maria cam]a4 ,! ,g]man ,ica cam]as4 ,^! are l>g] editions ( ! light wood h& cam]a already describ$1 b ) ! addition ( a ,b[d5-wire %utt] release4 ,! body ( ! l>g] cam]as c>ries a di/9ctive feature 9 ! di/ance control ( ! l5s diafram1 work$ by means ( a lev] :i* actuates racks1 p9ions & connect+ rods lead+ to ! l5s4 ,on ! side ( ! cam]a body a %all[ box is provid$ = c>ry+ ! color filt] 9 its bayonet jo9t m\nt to fit on ! l5s 7,figs4 #db & #dc74 ,illu/ration3 ,,fig4 #db4--;,g]man a]ial cam]as4 ,illu/ration3 ,,fig4 #dc4--;,diagram ( ,g]man #ej c5timet] cam]a4 ,illu/ration3 ,,fig4 #dd4--,u4 ,s4 h&-op]at$ a]ial cam]a 7type ,m7 ) #aj & #bj in* cones4 ,! h&-op]at$ bag-magaz9e cam]a ( ! ,unit$ ,/ates ,air ,s]vice 7,type ,m7 is simil> to ! small h&-held cam]a1 b diff]s 9 ?ree respects3 a removable %utt] 7( ! v>iable-t5sion fix$-ap]ture type7 embody+ an auxili>y curta9 = capp+ dur+ ! sett+ op]ation2 a ,b[d5-wire %utt] release2 & ! employm5t ( a set ( /&>d int]*angeable cones to hold l5ses ( sev]al focal l5g?s4 ,! #bj in* & #aj in* cones are %[n 9 ,fig4 #dd4 ,! op]ation ( ?is cam]a is simil> to ! ,fr5* /&>d cam]as1 b n s simple because ( ! numb] ( motions requir$ 9 manipulat+ ! bag4 ,its *ief objection = w> "w lies 9 fact 9 ! magaz9e1 :i* %\ld be sup]s$$ by a two-comp>tm5t or o!r satisfactory type ( plate *ang+ *amb]4 ,! cam]a alone1 ) #bj in* cone1 weighs approximately #dj p\nds2 ! load$ magaz9e1 ) its plates 9 metal %ea?s1 #ae p\nds4 ,illu/ration3 ,,fig4 #de4--;,engli% ,c type a]ial cam]a4 ,! ,engli% ,c & ,e type cam]as4 ,! ,c & ,e type cam]as h n[ *iefly an hi/oric int]e/4 ,!y 7 ! fir/ us$ 9 ! ,engli% s]vice1 fix$ to ! fuselage1 & 7 lat] us$ 9 tra9+ "w 9 ,engl& & 9 ! ,unit$ ,/ates4 ,!y 7 nev] built = plates l>g] ?an #d #e in* nor = l5ses ( m ?an #ab in* focus1 a limitation set by ! l5ses available at ! "t ( _! design4 ,illu/ration3 ,,fig4 #df4--;,engli% type 8,e0 h&-op]at$ plate cam]a4 ,9 sev]al respects ! mode ( op]ation ( ! two types is ! same4 ,! unexpos$ plates are held 9 a magaz9e ly+ above ! cam]a1 9 ! axis ( ! l5s 7,fig4 #cb74 ,aft] exposure ! bottom plate is c>ri$ to "o side & all[$ to fall by ! action ( gravity into ! receiv+ magaz9e4 ,9 ! ,c type 7,fig4 #de7 an opaque slide is drawn betwe5 ! l5s & ! 7v>iable-op5+7 %utt] dur+ ! sett+ op]ation4 ,dur+ ! exposure p]iod ?is slide projects into a comp>tm5t on ! opposite side ( ! cam]a f ! receiv+ magaz9e1 ?us mak+ ! cam]a me*anism ?ree plates wide4 ,9 ! ,e type 7,fig4 #df71 a flap ov] ! l5s makes x possible to disp5se ) ! slid+ scre51 & r$uces ! cam]a to ab\t ! wid? ( two plates4 ,9 ! ,c type ! plates are *ang$ by a h&le on top ( ! cam]a2 9 ! ,e type provision is made = di/ance control by cords1 & = %utt] release by a ,b[d5 wire4 ,9 bo? cam]as ! op]ation ( plate *ang+ also sets ! %utt]1 a def9ite advance ov] ! two prep>atory motions 9 ! ,fr5* app>atus4 ,! ,c type 0 con/ruct$ ( wood1 ! ,e ( metal4 ,illu/ration3 ,,fig4 #dg4--;,italian 7,pis]9i & ,mond9i7 two comp>tm5t magaz9e h&-op]at$ cam]a4 ,italian two-comp>tm5t magaz9e cam]a4 ,a cam]a design$ by ,pis]9i & ,mond9i 0 us$ to "s ext5t by ! ,italian s]vice t[>d ! close ( ! w> 7,fig4 #dg74 ,?is has ! desirable feature j not$ 9 ! ,c & ,e cam]as3 ! op]ations ( plate *ang+ & %utt] sett+ are p]=m$ 9 a s+le motion4 ,unlike ^? cam]as1 h[ev]1 ! plates are *ang$ f "o comp>tm5t to ano!r ( ! magaz9e already describ$1 )\t dep5d5ce on gravity1 by an entirely positive %ift+ action4 ,! sett+ ( ! self-capp+ focal-plane %utt] is accompli%$ by a project+ f+] engag+ ! %utt] me*anism4 ,cam]as ( ?is g5]al type1 built = #ah by #bd c5timet] plates1 ) int]*angeable l5s cones1 removable %utt]s1 & pref]ably magaz9es 9 :i* ! c5t] ( gravity does n %ift z ! plates are *ang$1 repres5t ! next /ep 9 advance ( ! ,fr5* practice1 & may inde$ prove all t is necess>y or desirable 9 cam]a complexity = peace-"t photography f ! air4 ,! /&>d ,italian cam]a & simil> types4 ,! cam]a 7,lamp]ti7 :i* ! ,italian ,air ,s]vice us$ almo/ exclusively dur+ ! w> exemplifies a type q diff]5t f any?+ z yet describ$ 7,figs4 #dh & #di74 ,plates to ! numb] ( tw5ty-f\r 7#ac #ah cm47 are load$ into a *amb] at ! top ( ! cam]a4 ,ea* plate is held 9 a septum furni%$ ) project+ lugs at "o end4 ,a lev] act+ ?r\gh a ,b[d5 wire1 exposes ! bottom plate1 :i* !n sw+s d[nw>d ab\t ^! lugs z pivots1 & is =c$ by a pair ( f+]s into a comp>tm5t at ! side4 ,! betwe5-!-l5s %utt] has a s+le spe$ ( #a_/aej second1 & v>iation ( exposure is a*iev$ by alt]+ ! l5s ap]ture4 ,illu/ration3 ,,fig4 #dh4--,v>i\s plate *ang+ devices4 ,! great advantage ( ?is cam]a is its simplicity1 a s+le motion p]=m+ all ! op]ations4 ,its disadvantages are its dep5d5ce on gravity = op]ation1 its betwe5-!-l5s %utt]1 ! limitation set to ! numb] ( exposures1 & ! necessity = remov+ ! :ole cam]a to take out ! plates = develop+4 ,9 actual practice ! cam]a has work$ out well4 ,! bett] light f\nd 9 ! ,italian z contra/$ ) ! nor!rn !atre ( w> makes ! betwe5-!-l5s %utt] at high spe$ adequate1 :ile ! limitation to ! numb] ( exposures has be5 met by c>ry+ sev]al complete cam]as 9 ea* plane4 ,because ( ! ,b[d5-wire op]ation ^! cam]as ne$ n be accessible to ! obs]v] or pilot1 s t ! practice ( c>ry+ !m 9 s+le-seat]s 0 common4 ,attempts at /&>dization ( ,alli$ practice ?r\gh ! adoption ( /&>d l5s cones 71 ( c\rse1 out ( ! "q ) ?is cam]a4 ,) its limitations ( %utt] effici5cy & plate size x is d\btful :e!r x w\ld h be5 satisfactory outside ! s]vice = :i* x 0 develop$4 ,illu/ration3 ,,fig4 #di4--;,italian 7,lamp]ti7 s+le-motion plate cam]a1 on anti-vibration tray4 ,! limitations set by ! betwe5-!-l5s %utt] 9 ?is type h be5 ov]come 9 an exp]im5tal cam]a along simil> l9es made by ! ,premo ,works ( ! ,ea/man ,kodak ,company1 & 9 ! ,fr5* ,aubry model 7,fig4 #dh74 ,^! employ focal-plane %utt]s :i* sw+ out ( ! way & are set z ! expos$ plate sw+s or drops to ! receiv+ *amb]4 ,! dep5d5ce on gravity 9 ?is type c\ld d\btless be avoid$ by positive f+] me*anisms4 ,if s1 ! resultant cam]as1 set & expos$ by a s+le motion1 w\ld acquire a highly desirable simplicity ( op]ation4 ,!y w\ld h peculi> m]it because ( ! v %ort int]val requir$ betwe5 exposures--a *>act]i/ic ne$$ = mak+ l[ /]eo-oblique views4 ,! cam]as j m5tion$ h1 h[ev]1 dep>t$ f> 9 =m f ! l9es ( /&>diz$ practice & h n be5 foll[$ up4 ,,*apt] ,,ix ,,semi-,,automatic ,,a]ial ,,plate ,,cam]as ,9 ! h&-op]at$ cam]a ! limit to progress is set :5 ! numb] ( op]ations is r$uc$ to a m9imum4 ,9 cam]as us+ ! l>g] sizes ( plates a r$uction 9 ! numb] ( op]ations almo/ inevitably results 9 inflict+ consid]able muscul> labor ^u ! op]ator4 ,fur!rmore1 di/ance op]ation becomes difficult to arrange =1 because ! common reliance--! ,b[d5 wire--is unfitt$ = heavy loads4 ,consequ5tly1 = sett+ ! %utt] & *ang+ ! plates we mu/ resort to "s o!r s\rce ( p[] ?an ! obs]v]'s arm4 ,air-driv5 turb9es or propell]s h be5 us$ on a]ial cam]as1 z well z clock-"w1 & also electric p[]1 ! latt] d]iv$ ei!r f a g5]ator or f /orage batt]ies4 ,! relative m]its ( ^! s\rces ( p[] =m ! subject ( a sep>ate *apt]4 ,m5tion only is "h made ( ! =m ( drive actually employ$ 9 connection ) ! v>i\s cam]as4 ,! t]m semi-automatic cam]a is be/ us$ to designate t type 9 :i* ! obs]v] 7or pilot7 has m]ely to release ! %utt]1 aft] :i* ! me*anism p]=ms all ! op]ations necess>y to prep>e = ! next exposure4 ,!re has be5 "s diff]5ce ( op9ion z to :e!r x is ev] advisable to g fur!r ?an ?is ) plate cam]as4 ,! ,engli% ,s]vice holds t completely automatic expos+1 9 addition to plate *ang+1 is apt to enc\rage ! mak+ ( _m m pictures ?an necess>y1 involv+ c>ry+ an excessive weight ( plates4 ,! ,fr5* ,s]vice has r g5]ally favor$ entirely automatic cam]as 9 !ory1 al?\gh dur+ ! w> practically all ! "w ( ! ,fr5* army 0 done by ! h&-op]at$ cam]as already describ$4 ,! ,engli% ,l ,type ,cam]a4--,! ,l1 a modification ( ! e>li] ,c & ,e models1 diff]s f its pr$ecessors *iefly 9 ! addition ( a me*anism :i* :5 connect$ ) a suitable s\rce ( p[] c be us$ :5ev] desir$ = *ang+ ! plates & sett+ ! %utt]4 ,z 9 ! ,c & ,e types1 all unexpos$ plates are c>ri$ 9 a magaz9e above ! cam]a1 :ile ! expos$ plates are %ift$ 9 a horizontal direction to "o side & fall !nce to a receiv+ magaz9e4 ,illu/ration3 ,,fig4 #ej4--;,am]ican model1 ,engli% 8,l0 type semi-automatic cam]a4 ,illu/ration3 ,,fig4 #ea4--,me*anism ( 8,l0 cam]a4 ,fig4 #ej %[s ! ,am]ican model1 :i* is a copy1 ) modifications1 ( ! orig9al ,engli% design4 ,its weight ) "o load$ magaz9e is ab\t #ce p\nds4 ,its mann] ( function+ may be /udi$ f ! picture ( ! me*anism 7,fig4 #ea74 ,! "p ( ! me*anism to ! left is inop]ative dur+ h& op]ation1 & ! l>ge too!d :eel is lock$ by ! removable p9 %[n hang+ on its *a9 9 ,fig4 #ej4 ,to *ange a plate & set ! %utt] ! project+ lev] 7,fig4 #ej7 is ?r[n ov] & back4 ,?is causes a slid+ tray1 9 :i* ! expos$ plate re/s1 to travel to ! "r1 ov] ! receiv+ magaz9e1 :]e ! plate is dropp$4 ,aft] ?is ! tray returns to ! left expos+ position4 ,simultane\sly ! %utt] is w\nd up4 ,exposure is made ei!r by press+ d[n ^u ! plung]1 or bett]1 by us+ a ,b[d5 wire4 ,provision = bo? me?ods ( expos+1 "o = ! pilot & "o = ! obs]v]1 is %[n 9 ,fig4 #ha4 ,! %utt] is ! v>iable-ap]ture type already describ$1 provid$ 9 addition ) a t5sion adju/m5t on ! back ( ! cam]a4 ,a flap beh9d ! l5s does ! capp+ dur+ ! sett+ op]ation4 ,= p[] op]ation ! cam]a is connect$ ?r\gh a flexible %aft ) a w9d driv5 propell] 7,figs4 #ej1 #hc & #hd74 ,! lock+ p9 is n[ mov$ ov] f ! too!d :eel to ! lev] arm1 s t ! rotation ( ! worm driv+ ! l>ge too!d :eel =ces ! lev] ?r\gh its plate *ang+ motion4 ,to prev5t repetition1 a "p ( ! p]iph]y ( ! too!d :eel is cut out1 s t x /ops :5 its cycle is run4 ,:5 ! ,b[d5 wire actuates ! %utt] release x =ces ! too!d :eel ar\nd into engagem5t 7aid$ by "o spr+ too?7 & s />ts ! cycle once m4 ,:5 connect$ ) ! air propell] ! worm is rotat$ cont9u\sly4 ,o!r s\rces ( p[]--an electric motor1 = in/ance--c be atta*$ ?r\gh ! same k9d ( flexible %aft4 ,if an electric motor is employ$ x may be run cont9u\sly or x may be op]at$ ) an insulat$ sector introduc$ into ! l>ge too!d :eel s t ! electric circuit is brok5 & ! motor /ops until ! :eel is once m =c$ ar\nd by ! expos+ lev]4 ,faults ( ! ,l cam]a4 ,! ,l cam]a 0 ! ma9/ay ( ! ,engli% ,air ,s]vice4 ,9 fact = ! la/ two ye>s ( ! w> x 0 practically ! only cam]a ! ,engli% us$1 & !y ?\ght highly ( x4 ,x is1 ( c\rse1 subject to ! limitation ( small plate size & %ort focus l5s4 ,x is 9 _m ways an inconv5i5t cam]a to h&le4 ,= in/ance1 ! upp] magaz9e _c be clos$ or remov$ until all ! plates are pass$ ?r\gh4 ,its dep5d5ce ^u gravity = ! plate *ang+ op]ation is a fundam5tal weakness1 responsible = its frequ5t t5d5cy to jam 9 ! air4 ,exp]i5ce made ! ,engli% obs]v]s v exp]t 9 reliev+ ^! jams4 ,sometimes !y w\ld turn ! propell] backw>d 7m\nt+ x 9 an accessible position to provide = ?is cont+5cy71 sometimes !y w\ld %ake or ?ump ! cam]a4 ,b :ile ^! make%ifts w\ld s]ve to secure pictures--! *ief object1 ( c\rse1 ( ! photographic s]vice--!y c sc>cely be said to r5d] ! cam]a satisfactory4 ,moreov]1 ! propell] drive has n be5 univ]sally approv$1 z x furni%es an additional me*anism to make tr\ble4 ,s9ce x is n feasible to *ange f p[] to h& op]ation :ile 9 ! air1 ! cam]a is put out ( commission :5ev] ! propell] or %aft is disabl$4 ,b[d5-wire controls = bo? plate *ang+ lev] & %utt] release 7 common 9 ! ,briti% s]vice1 :i* consid]$ ! extra op]ation or ! extra muscul> ex]tion unimportant :5 comp>$ ) ! great] assurance ( reliable action4 ,! ,engli% ,,lb & ,,bm ,cam]as4--,dur+ ! clos+ mon?s ( ! w> an improv$ ,l type cam]a 0 con/ruct$1 ! ,,lb4 ,?is diff]s f ! ,l 9 a numb] ( detail *anges1 dictat$ by exp]i5ce4 ,! %utt] is n[ made removable & self-capp+4 ,pivot$ lugs are provid$ to hold ! expos$ plate horizontal until ! v in/ant x drops1 9 an ef=t to prev5t jams caus$ by ! plates pil+ up at an angle 9 ! receiv+ magaz9e4 ,! *ief addition1 h[ev]1 is ! provision ( sev]al int]*angeable cones & cyl9d]s1 = c>ry+ l5ses ( focal l5g?s f #d to #bj in*es4 ,fig4 #ie %[s ! ,,lb ) #bj in* l5s cyl9d] m\nt$ on a bell crank support 9 ! cam]a bay ( an ,engli% plane4 ,! ,,bm cam]a is b a l>g] edition ( ! ,,lb1 = #ah #bd c5timet] plates4 ,x also c>ries sev]al int]*angeable l5s cones4 ,! ,am]ican model de,ram cam]a4--,! rot>y *ang+ box devis$ by ,lieut5ant de,ram ( ! ,fr5* army & incorporat$ 9 8 entirely automatic plate cam]a1 has be5 adapt$ by ! ,am]ican ,air ,s]vice to a v successful semi-automatic cam]a4 ,fig4 #eb %[s ! pr9ciple ( ?is *ang+ box4 ,! pile ( fifty plates1 ea* 9 its %ea?1 is c>ri$ 9 a rectangul> box op5 at top & bottom4 ,! l[] plate next ! focal-plane %utt] is fir/ expos$2 ! pile !n rotates ab\t a horizontal axis ?r\gh a complete turn4 ,:5 ! expos$ plate arrives 9 a v]tical position x is all[$ to drop (f1 by ! op5+ ( cam actuat$ f+]s1 & lodges aga9/ ! side ( ! enclos+ cam]a box prop]4 ,/ill fur!r along 9 ! cycle ! plate is ?r[n (f f its lodg+ place into a 8scoop0 on ! top ( ! rotat+ conta9] & laid on ! top ( ! plate pile4 ,mean:ile ! curta9 ( ! focal-plane %utt] w9ds up1 at ! same "t t x is depress$ out ( ! way ( ! revolv+ plate conta9]4 ,al?\gh ! plate *ang+ op]ation dep5ds on gravity1 x nev]!less functions satisfactorily up to #cj degrees f ! v]tical4 ,! %utt] 9 ?is model is ! v>iable-ap]ture fix$-t5sion type1 adju/$ by pivot$ idl]s 7,fig4 #bh74 ,9 ! expos+ position x runs )9 ?ree millimet]s ( ! plate surface1 & is !re=e ( high effici5cy = all op5+s4 ,capp+ dur+ ! op]ation ( sett+ is p]=m$ by flaps at ! bottom ( ! cam]a body4 ,int]*angeable cones are suppli$ = l5ses ( v>i\s focal l5g?s4 ,= h& op]ation ! *ang+ box is turn$ ov] by means ( a h&le1 :i* rotates f\r times = ! complete cycle 7,fig4 #ij74 ,= semi-automatic op]ation an additional me*anism is provid$ on ! side ( ! rectangul> cam]a body1 copi$ ) "s necess>y modifications aft] ! ,l cam]a p[] drive4 ,f ! obs]v]'s /&po9t ! op]ation ( ! :ole cam]a is ! same z 9 ! ,l cam]a1 ) ! important exception t p[] op]ation 9 no way int]f]es ) h& op]ation4 ,inde$1 ! h& c help out if ! p[] flags or fails4 ,illu/ration3 ,,fig4 #eb4--;,diagram ( automatic plate cam]a movem5ts4 ,?is cam]a is mo/ satisfactorily driv5 by a #ab volt ,,hp electric motor work+ ?r\gh a flexible %aft atta*$ to a swivel connection at ! front ( ! semi-automatic drive box4 ,a *ange once e f\r to five seconds is possible1 b great] spe$ is apt to ?r[ ! *ang+ plate too viol5tly = safety4 ,! *ief practical objection to ?is cam]a is its bulk4 ,its great height makes x impractical = _m planes4 ,its weight ( ne>ly a hundr$ p\nds is a =midable load = a plane to c>ry1 b ?is is no m & probably less ?an t ( any o!r cam]a :5 tak5 up ) ! same numb] ( plates 9 magaz9es4 ,! price paid = economiz+ 9 magaz9e weight is t ! :ole cam]a body1 exclud+ ! l5s cone1 mu/ be c>ri$ to & f ! plane = bo? load+ & unload+4 ,,*apt] ,x ,,automatic ,,a]ial ,,plate ,,cam]as ,g5]al ,*>act]i/ics4--,! ideal 9 ! automatic plate cam]a is to provide a me*anism :i* w n only *ange ! plates & set ! %utt]1 z does ! semi-automatic1 b make ! exposures z well1 at regul> int]vals "u ! control ( ! op]ator4 ,su* a :olly automatic cam]a w\ld leave ! obs]v] entirely free = o!r activities ?an photography & x is to meet ?is tactically desirable aim t ! w>-"t /riv+ = automatic cam]as 0 due4 ,x is obvi\s t ! "o ess5tial diff]5ce betwe5 ! automatic & semi-automatic types lies 9 ! self-conta9$ expos+ me*anism ) its device = ! tim+ ( ! exposures4 ,!re is no difficulty 9 arrang+ = ! driv+ p[] to trip ! %utt]1 b x is no easy matt] to design app>atus :i* w space ! exposures equally1 & at ! same "t p]mit ( a v>iation ( ! int]val4 ,x is inde$ ! crux ( ! problem ( automatic cam]a design to provide = ! easy & c]ta9 v>iation ( ! int]val f ! two or ?ree seconds dem&$ = l[ /]eoscopic views to ! m9ute or m t high altitude wide angle mapp+ may p]mit4 ,?is problem is "o intimately b\nd up ) ! "q ( means ( p[] drive & its regulation1 & w be treat$ 9 "p 9 t connection4 ,x is to be not$1 h[ev]1 t !re are 9 g5]al two modes ( exposure int]val regulation4 ,"o is by v>iation 9 ! spe$ at :i* ! :ole cam]a me*anism is driv54 ,! o!r is by ! m]e addition to a semi-automatic cam]a ( a "t controll$ release :i* affects 9 no way ! spe$ ( ! plate *ang+ op]ation4 ,9 _m respects ! latt] is ! be/ way to make an automatic cam]a4 ,:ile ! advantages ( automatic cam]as are great x mu/ n be ov]look$ t a cam]a :i* c only be op]at$ automatically is ( limit$ usefulness4 ,x is n suit$ = 8spott+0 at any def9ite in/ant1 z1 = illu/ration1 at ! mom5t ( explosion ( a bomb4 ,x %\ld1 !re=e1 be ! aim ( ! automatic cam]a design] to s build ! app>atus t x c1 at w1 be us$ semi-automatically4 ,9 addition1 to meet ! cont+5cy ( any break-d[n 9 ! s\rce ( p[]1 ! cam]a %\ld be capable ( h& op]ation1 z 9 ! case ( ! ,am]ican semi-automatic de,ram4 ,9 %ort1 ! automatic cam]a %\ld n be a sep>ate & diff]5t type2 x %\ld m]ely h an additional me?od ( op]ation4 ,c]ta9 desirable me*anical features ( all a]ial cam]as h already be5 enum]at$4 ,"s ( ^! may be repeat$ "h ) ! addition ( o!rs peculi> to automatic cam]as4 ,z a g5]al caution1 me*anical motions dep5d+ on gravity or on spr+s %\ld be avoid$4 ,movem5ts adv]sely affect$ by l[ temp]atures 7#bj to #cj degrees bel[ z]o1 ,c5tigrade71 are unsuitable4 ,all adju/m5ts call$ = 9 ! air mu/ be op]able by di/ance controls ^: p>ts are l>ge1 rugg$1 & n dep5d5t on s\nd or delicate t\* = _! correct sett+4 ,! c5t] ( gravity ( ! cam]a %\ld n *ange dur+ op]ation 7important 9 connection ) ! problem ( susp5sion74 ,! cam]a %\ld "w 9 ! oblique z well z 9 ! v]tical position4 ,! p[] requir$ = op]ation mu/ n exce$ t available on ! plane4 ,electrical app>atus1 = in/ance1 %\ld n dem& m ?an #ajj watts4 ,any devices :i* dim9i% ! weight ( ! cam]a are p>ticul>ly desirable 9 automatic plate cam]as1 because ( ! l>ge numb] ( exposures :i* su* cam]as enc\rage4 ,= in/ance1 if ! plates c\ld be h&l$ )\t plac+ !m 9 metal %ea?s we %\ld ga9 a sub/antial r$uction 9 weight 7! %ea?s weigh ne>ly z mu* z ! plates7 z well z 9 ! "t necess>y = h&l+4 ,! ,brock ,automatic ,plate ,cam]a4--,?is cam]a is some:at simil> to ! same design]'s film cam]a1 bo? 9 %ape1 9 size1 & 9 its employm5t ( a heavy spr+ motor = ! driv+ p[]4 ,x uses #d #e in* plates1 & c>ries a #aj to #ab in* l5s4 ,! plate-*ang+ op]ation is unique4 ,z %[n diagrammatically 9 ,fig4 #eb1 ! unexpos$ plates are c>ri$ 9 a magaz9e on top ( ! cam]a1 ! expos$ ones 9 a magaz9e ins]t$ 9 ! body ( ! cam]a1 directly bel[ ! unexpos$ magaz9e4 ,! bottom plate ( ! expos$ pile drops into a slid+ frame & is c>ri$ along ! top ( ! cam]a to ! expos+ position4 ,aft] exposure1 ! plate is c>ri$ back & drops into ! receiv+ magaz9e4 ,9 ord] = ! plate to fall only ! prop] di/ance at ea* /age ( ! cycle1 special plate %ea?s are necess>y4 ,^! are cut away to =m edge patt]ns :i* cle> or engage control f+]s s z to ride or fall ?r\gh ! slid+ frame z requir$4 ,! cam]a is entirely automatic 9 op]ation4 ,regulation ( ! exposure int]val is by a special =m ( v>iable l5g? escapem5t controll$ ?r\gh a ,b[d5 wire1 9 a mann] p>allel to t 9 ! ,brock film cam]a1 describ$ else:]e4 ,^! plate cam]as 7 nev] produc$ 9 quantity4 ,folm] #ac #ah ,c5timet] ,automatic ,cam]a4--,?is cam]a1 also nev] manufactur$ 9 quantity1 is %[n 9 ,fig4 #ec1 & a sket* ( its mann] ( op]ation is includ$ 9 ! ensemble ( automatic cam]a diagrams 7,fig4 #eb74 ,its mo/ di/9ctive feature is p]haps ! use ( a two comp>tm5t magaz9e4 ,?is is simil> 9 =m to ! "o already describ$ 9 connection ) ! h&-held cam]as1 b l>g]1 to hold eighte5 #ac #ah c5timet] plates4 ,! unexpos$ plates are plac$ 9 "o comp>tm5t1 & aft] exposure are %ift$ to ! o!r4 ,! transf] is effect$ by ! motion ( a rack1 :i* is "p ( ! magaz9e & :i* is driv5 by a too!d p9ion1 also "p ( ! magaz9e1 :i* 9 turn engages 9 a too!d :eel project+ upw>d f ! cam]a body4 ,?is too!d :eel is turn$ fir/ 9 "o direction & !n 9 ! o!r by an arrangem5t ( ge>s & lev]s driv5 by ! s\rce ( p[]1 :i* z %[n 9 ,fig4 #ec is a w9d turb9e connect$ ?r\gh a flexible %aft4 ,op]ation is ei!r automatic or semi-automatic z desir$1 & ! cam]a c be put ?r\gh its cycle by h& if necess>y4 ,illu/ration3 ,,fig4 #ec4--;,folm] #ac #ah c5timet] automatic & semi-automatic plate cam]a4 ,illu/ration3 ,,fig4 #ed4--;,fr5* model de,ram automatic plate cam]a4 ,z ) sev]al o!r designs1 ! completion ( ! work+ model ( ?is cam]a occurr$ aft] agreem5ts _h be5 rea*$ by ! ,allies1 z to plate size1 /&>d l5s cones1 & o!r features1 n easily incorporat$ 9 x1 ?us mak+ manufacture inadvisable4 ,! validity ( ! design = peace-"t "w is1 ( c\rse1 n affect$ by ?is fact4 ,! de,ram ,cam]a4--,! only completely automatic plate cam]a actually produc$ comm]cially be=e ! end ( ho/ilities 0 ! ,fr5* model de,ram 7,fig4 #ed74 ,its plate-*ang+ action has already be5 describ$ 9 connection ) ! ,am]ican semi-automatic model 7,figs4 #eb1 #ij & #ia74 ,x diff]s f ! ,am]ican model 9 ! %utt]1 :i* is ( ! self-capp+ v>iety1 c>ri$ on a ris+ & fall+ frame2 & 9 ! expos+ me*anism4 ,! latt] embodies a clut* ^: po9t ( atta*m5t to a uni=mly rotat+ disc 9 ! cam]a is gov]n$ ?r\gh a ,b[d5 wire1 :]eby ! int]val betwe5 ! plate-*ang+ op]ation & ! %utt] release is v>i$4 ,! int]vals are indicat$ by figures on ! dial to :i* ! obs]v]'s end ( ! ,b[d5 wire is atta*$4 ,! s\rce ( p[] = ! cam]a is a con/ant spe$ propell]4 ,complete semi-automatic op]ation is n possible1 z an int]val ( #a to #b seconds elapses betwe5 ! "t a s+le exposure is call$ = & its occurr5ce4 ,no arrangem5t is provid$ = h& op]ation4 ,x w be not$ t :ile ?is cam]a is a true automatic app>atus x does n meet ev5 a majority ( ! requirem5ts li/$ above z f\nd desirable by exp]i5ce4 ,!re exi/s a great opportunity = design+ & develop+ an entirely satisfactory automatic plate cam]a--provid$ x is agre$ t any?+ m ?an semi-automatic op]ation is ev] advisable = plates4 ,,*apt] ,,xi ,,a]ial ,,film ,,cam]as ,! weight ( ! glass & ! %ea?s 9 ! plate cam]a =ms its mo/ s]i\s drawback4 ,?is weight mu/ be reckon$ at lea/ ?ree qu>t]s ( a p\nd = ea* #ah #bd c5timet] plate4 ,consequ5tly1 ) ! use ( ^! l>ge plates1 & ) ! dem&s = ev] increas+ numb]s ( pictures to be tak5 on long reconnaissance flights1 a s]i\s conflict arises betwe5 ! weight ( ! photographic equipm5t & ! c>ry+ capacity ( ! plane4 ,among plate cam]as probably ! mo/ economical 9 weight is ! de,ram4 ,x c>ries fifty #ah #bd c5timet] plates1 & has a total weight ( approximately #ajj p\nds4 ,an advance to #ajj or #bjj plates--n feasible 9 ! de,ram con/ruction--ev5 if we assume ! lighte/ possible magaz9es1 w\ld br+ ! weight ( cam]a & plates to #aej or #bjj p\nds1 :i* w\ld be detrim5tal to ! balance & w\ld s]i\sly infr+e on ! fuel c>ry+ capacity & ceil+ ( any ord9>y reconnaissance plane4 ,e>ly & p]si/5t att5tion 0 !re=e paid to ! possibilities ( celluloid film 9 rolls1 z us$ s widely 9 h& cam]as & 9 mov+ picture "w4 ,! two great advantages ( film w\ld be its practically negligible weight 7approximately "o-t5? t ( plates1 n includ+ %ea?s7 & its small bulk1 :i* w\ld p]mit ! greate/ fre$om 9 ! developm5t ( entirely automatic cam]as to make exposures by ! hundr$s in/ead ( by ! doz5s4 ,c]ta9 disadvantages 7 =ese5 at ! outset3 ! difficulty ( hold+ ! film flat & immune f vibration 9 ! l>g] sizes2 ! difficulty ( quickly develop+ & dry+ l>ge rolls2 ! "q :e!r z good spe$ or color s5sitiv5ess c\ld be obta9$ 9 s5sitive emulsions :5 fl[$ on a celluloid base z on glass4 ,e>ly trials reveal$ a fur!r problem to solve3 h[ to elim9ate ! dis*>ge ( /atic electricity occurr+ at high altitudes1 especially :5 ! wea!r is cold4 ,z f> z cam]a con/ruction is conc]n$ ! *ief problems are to hold ! film flat1 & to elim9ate /atic4 ,me?ods ( ,hold+ ,film ,flat4--,sev]al means h be5 propos$ & us$ = hold+ ! film flat4 ,disreg>d+ m]e pressure guides at ! side1 :i* are suitable only = small area films 7up to #d #e in*71 ! successful means h tak5 ?ree =ms3 pressure ( a glass plate1 pressure ( ! %utt] curta91 & suction4 ,a glass pressure plate c be us$ 9 ei!r ( two ways2 ! film may be 9 cont9u\s contact ) x or may be press$ aga9/ its surface only at ! mom5t ( exposure4 ,! advantage ( ?is fir/ me?od lies solely 9 its me*anical simplicity2 its disadvantage 9 ! likelihood ( scrat*es or pressure m>k+s on ! film4 ,:]e a glass plate is us$ !re is always ! *ance ( a du/ or dirt film accumulat+1 or ( ! cond5sation ( moi/ure1 to impair ! quality ( ! negative4 ,!re is1 moreov]1 an inevitable loss ( light 7ab\t #aj71 toge!r ) "s slight di/ortion1 due to ! b5d+ ( ! m>g9al oblique rays ?r\gh ! ?ickness ( ! glass4 ,9 cases :]e a filt] w\ld normally be employ$1 ! loss ( light is m9imiz$ by us+ yell[ glass = ! plate1 s t x s]ves = filt] & film hold] z well4 ,pressure ( ! %utt] curta9 is utiliz$ 9 ! ,du*atelli] film cam]a by furni%+ ! edges ( ! curta9 ap]ture ) heavy velvet /rips1 ^: light & g5tle pressure dur+ ! passage ( ! %utt] holds ! film aga9/ a metal back4 ,9 _m ways ?is is ! simple/ film-hold+ device2 x occasions no loss ( light1 & ne$s no me*anical movem5ts or ext]nal accessories1 su* z are call$ = 9 ! suction devices next describ$4 ,!re is always dang] ( m>k+s on ! film1 if ! velvet is n ( ! "r ?ickness & s(tness1 & ! op]ation & spe$ control ( ! %utt] are necess>ily complicat$ by ! additional frictional load4 ,suction ( ! film aga9/ a p]=at$ back plate has be5 f\nd a v successful means ( secur+ flatness4 ,suction at ! mom5t ( exposure may be produc$ by ! action ( a bell[s1 :i* has be5 compress$ be=eh& by ! cam]a-driv+ me*anism4 ,cont9u\s suction c be produc$ ei!r by a cont9u\sly driv5 pump1 or by a ,v5turi tube plac$ outside ! fuselage4 ,! ,v5turi tube 7,fig4 #ee7 consi/s ( a pipe built up ( two cones1 plac$ v]tex to v]tex1 to =m a con/riction4 ,:5 air is =c$ ?r\gh ?is at high velocity suction is produc$ 9 a small diamet] tube tak5 (f at ! con/riction4 ,a suction ( two c5timet]s ( m]cury1 act+ ?r\gh holes ab\t "o c5timet] equidi/ant f ea* o!r 9 ! back plate1 has be5 f\nd adequate to hold flat a film #ah #bd c5timet]s4 ,"o m]it ( suction appli$ only at ! mom5t ( exposure is t ! film-driv+ me*anism does n h to "w aga9/ ! drag ( ! suction4 ,cont9u\s suction1 on ! o!r h&1 gives a long] opportunity = flatt5+ out k9ks 9 ! celluloid1 & easily p]mits movem5t ( ! film dur+ ! exposure1 ei!r = ! purpose ( p]mitt+ a long] exposure or = ! purpose ( prev5t+ di/ortion due to ! focal-plane %utt]4 ,a disadvantage ( cont9u\s suction is ! production ( m9ute scrat*es on ! celluloid surface z x drags ov] ! suction plate4 ,^! are ord9>ily too small to cause tr\ble1 b may %[ up :5 pr9t+ is done 9 an enl>g+ cam]a4 ,illu/ration3 ,,fig4 #ee4--,v5turi tube on side ( plane4 ,/atic dis*>ges are produc$ by ! friction ( ! celluloid aga9/ ! pressure back or o!r surfaces ) :i* x comes into contact4 ,!y %[ 9 ! develop$ film z bran*+ tree-l /reaks 7,fig4 #ef7 & 9 cold dry wea!r may be num]\s en\gh to ru9 a picture4 ,! dis*>ges are noticeably less frequ5t ) film coat$ on ! back ) gelat9e 78,n4,c4071 b ! extra gelat9e surface is extremely undesirable4 ,:5 h&l$ by develop+ ma*9es1 z l>ge rolls mu/ be1 ?is back gelat9e surface becomes scrat*$ & bruis$ 9 a s]i\s mann]4 ,pla9 unback$ film is mu* to be pref]r$ if ! /atic c be obviat$4 ,to avoid /atic1 x is necess>y to provide = ! imm$iate dissipation ( all acquir$ electrical *>ges4 ,exp]im5ts made by ! ,unit$ ,/ates ,air ,s]vice h %[n t no?+ is s good z r r\gh clo?1 ?or\ghly impregnat$ ) graphite1 held 9 close contact ) ! celluloid dur+ z great a portion ( its travel z possible4 ,9 ! ,unit$ ,/ates ,air ,s]vice film cam]a :i* uses suction ?r\gh a p]=at$ back plate1 ! plate has be5 cov]$ ) ?9 graphit$ clo?1 & simil> clo? %eets are press$ aga9/ ! film rolls by %eets ( spr+ metal 7,fig4 #fe74 ,9 cam]as ) ?is equipm5t no tr\ble has be5 exp]i5c$ ) /atic4 ,illu/ration3 ,,fig4 #ef4--,pr9t f film cam]a negative1 %[+ /atic dis*>ge1 & 7upp] left-h& corn]7 record ( altitude & compass direction made by ,williamson film cam]a auxili>y l5s 7,fig4 #eh74 ,repres5tative ,film ,cam]as4--,! ,engli% ,f type 7,williamson74 ,?is is "o ( ! e>lie/ cam]as design$ = film1 z is indicat$ by ! nature ( ! p[] drive1 :i* presupposes t ! cam]a is to be c>ri$ on ! outside ( ! fuselage4 ,its ess5tial features are %[n 9 ,figs4 #eg & #eh4 ,x consi/s ( a rectangul> box ) a cone at ! front on :i* is m\nt$ a propell]1 int5d$ to be rotat$ by ! w9d made by ! motion ( ! plane4 ,?is drives1 ?r\gh a gov]nor controll$ friction clut*1 a tra9 ( ge>s :i* draws ! 7#e #d in*7 film across ! focal plane1 sets & exposes ! %utt] at regul> int]vals4 ,illu/ration3 ,,fig4 #eg4--;,engli% type 8,f0 7,williamson7 automatic film cam]a4 ,above ! cam]a1 support$ on a tripod1 are a compass & altimet]1 bo? record+ on a s+le dial1 illum9at$ f bel[ by ! light reflect$ f a circul> :ite disc pa9t$ on top ( ! cam]a4 ,an image ( ! dial is ?r[n on a corn] ( ! film by a l5s1 ^: %utt] is actuat$ 9 syn*ronism ) ! ma9 focal-plane %utt]4 ,no special means are provid$ = hold+ ! film flat4 ,special film ) p]=at$ edges is us$4 ,! cam]a 0 design$ = mapp+ "w on ! ,mesopotamian & o!r fronts :]e no maps at all exi/$4 ,! ,du*atelli] cam]a is ess5tially a film magaz9e to fit on ! /&>d ,fr5* de,maria cam]a bodies1 ( ! #ah #bd c5timet] size4 ,9 its simple/ =m x embodies a %utt] 7! regul> focal-plane %utt] ( ! cam]a be+ remov$7 & a film-mov+ me*anism1 bo? actuat$ by a s+le motion ( ! h&4 ,automatic & semi-automatic op]ation are accompli%$ by an auxili>y me*anism to :i* ,b[d5 wires f ! h& lev] are atta*$4 ,! motive p[] is an air propell]4 ,v>iation ( spe$ is obta9$ by *ang+ ! po9t ( contact ( a roll] on a friction disc1 ! disc be+ directly connect$ to ! propell] %aft1 ! roll] to ! cam]a drive %aft4 ,illu/ration3 ,,fig4 #eh4--;,int]ior ( type 8,f0 cam]a1 %[+ l5s = photograph+ compass & altitude read+s4 ,! mo/ di/9ctive features ( ! ,du*atelli] cam]a is its use ( ! focal-plane %utt] to hold ! film flat dur+ ! exposure4 ,z already expla9$1 ?is is accompli%$ by pressure1 velvet /rips on ! %utt] edges keep+ ! film close aga9/ ! back plate4 ,! return ( ! %utt] curta9 to ! 8set0 position is accompli%$ by lock+ x to ! film by p]=at+ po9ts1 s t x is pull$ across z ! film is w\nd4 ,?is introduces betwe5 ea* pair ( pictures a /rip ( trem5d\s ov] exposure1 z wide z ! curta9 op5+4 ,a fix$-ap]ture v>iable-t5sion %utt] is us$4 ,! magaz9e c>ries a roll ( film long en\gh = #bjj exposures1 fe$+ ! long way ( ! picture4 ,:5 film ne$s to be *ang$ 9 ! air1 ?is is done by *ang+ ! entire magaz9e1 includ+ its %utt]4 ,illu/ration3 ,,fig4 #ei4--;,g4 ,e4 ,m4 automatic film cam]a4 ,! ,g4 ,e4 ,m4 cam]a 7,fig4 #ei7 is a v light self-conta9$ clock-"w-drive cam]a tak+ #cf pictures six in*es squ>e4 ,! film is unroll$ f a small-diamet] fe$+ roll] on to a l>ge-diamet] receiv+ roll] to :i* ! driv+ me*anism is atta*$4 ,by ?is means approximately equal spac+ ( pictures on ! film is assur$4 ,! film is held flat by cont9u\s contact ) a glass plate1 :i* is made ( yell[ glass1 s t x s]ves at ! same "t z a color filt]4 ,! l5s--( #h to #ab in* focus--is equipp$ ) a s+le spe$ betwe5-!-l5s %utt]4 ,! op]ation ( ! cam]a is entirely automatic4 ,! int]val betwe5 pictures is controll$ by v>y+ ! clock-"w spe$1 ?r\gh a lev] on ! outside ( ! cam]a box4 ,protection ( ! cam]a f vibration is s\ght by support+ x on f\r spr+ cu%ions m\nt$ on a solid frame1 to :i* ! cam]a is held by spiral spr+s atta*$ to its sides4 ,illu/ration3 ,,fig4 #fj4--;,brock automatic film cam]a4 ,! ,brock ,film cam]a 7,fig4 #fj7 is an entirely automatic1 v compact self-conta9$ cam]a1 tak+ "o hundr$ #d #e in* pictures4 ,! motive p[] is clock-"w1 regulat$ 9 spe$ by an escapem5t controll$ by a flexible %aft c>ri$ to a dial :i* may be fa/5$ to ! in/rum5t bo>d or to "s o!r conv5i5t "p ( ! plane4 ,! l5s is #f1 #ab1 or #ah in* focus4 ,! %utt] is ( ! fix$-ap]ture v>iable-t5sion type1 ( long travel1 & ) a flap beh9d ! l5s = cov]+ dur+ ! sett+ p]iod4 ,none ( ! special means above describ$ = hold+ ! film flat are provid$4 ,a metal plate re/+ on ! back1 & a flat metal frame 9 front ) a #d #e in* ap]ture1 are consid]$ suffici5t *eck on ! excursions ( ! small-siz$ film4 ,a ball be>+ d\ble pivot$ frame s]ves to support ! cam]a 9 a p5dul\s mann]1 p]mitt+ x to assume a v]tical position aft] tilt+4 ,damp+ ( oscillations & vibration is arrang$ = by two pneumatic da% pots4 ,! ,g]man film mapp+ cam]a1 %[n 9 ,fig4 #fa1 is di/+ui%$ by a numb] ( special features4 ,! size ( ! pictures1 #f #bd c5timet]s1 is unusual4 ,x has its advantages1 h[ev]4 ,s9ce ! %ort dim5sion is 9 ! l9e ( flight1 ! maximum wid? ( field cov]$ by ! l5s is utiliz$ 7,fig4 #ag74 ,?is ( c\rse necessitates a l>g] numb] ( exposures to complete a /rip1 :i* is p]haps an add$ advantage1 s9ce ! n>r[] ! individual pictures ! bett] ! junctions w be1 especially if l>ge ov]laps are made4 ,?is prov$ to be ! case ) captur$ ,g]man mosaics4 ,difficulty is exp]i5c$ 9 mak+ ov]laps on a turn 7,fig4 #fb71 b ?is is n a vital objection4 ,! %utt] has a fix$ ap]ture1 n>r[] at ! c5t] ?an at ! ends1 to comp5sate = ! fall+ (f 9 illum9ation away f ! c5t] ( ! l5s4 ,no safety flap is ne$$ because ! curta9 moves 9 opposite directions on successive exposures1 !reby also comp5sat+ = %utt] di/ortion1 z has already be5 discuss$4 ,%utt] spe$ is controll$ by v>y+ ! t5sion ( ! actuat+ spr+4 ,illu/ration3 ,,fig4 #fa4--;,g]man automatic film cam]a4 ,! cam]a is driv5 by an electric motor1 connect$ to a set ( ge>s1 ^: %ift+ provides = spe$ v>iation4 ,! film is mov$ by rubb] roll]s :i* are cut away = "p ( ! circumf]5ce1 all[+ ! film to /& /ill until !y bite aga94 ,a yell[ glass pressure plate holds ! film dur+ ! exposure & s]ves z color filt] also 7,fig4 #fc74 ,an electric heat] is provid$ ne> ! %utt]1 z 9 all ! lat] ,g]man cam]as4 ,illu/ration3 ,,fig4 #fb4--,me?od ( jo9+ & pr9t+ film f ,g]man cam]a4 ,unit$ ,/ates ,air ,s]vice automatic film cam]a--,type ,k 7,figs4 #fd1 #fe1 #ib1 #ic1 #ih1 #ii74 ,?is is an entirely automatic cam]a1 manufactur$ by ! ,folm] & ,s*w+ ,division ( ! ,ea/man ,kodak ,co41 tak+ #ajj pictures ( #ah #bd c5timet] size at "o load+4 ,z ) all ! ,am]ican cam]as ( ?is size1 x uses ! /&>d l5s cones ( any desir$ focal l5g?4 ,! cam]a prop] consi/s ( a compact *amb] 9 :i* ! film roll]s are c>ri$ at ea* end =w>d ( ! focal plane1 ! %utt] ly+ betwe54 ,9 consequ5ce ( ?is arrangem5t ! v]tical dep? ( ! cam]a is ! absolute m9imum--%ort ( decreas+ ! l5g? ( ! optical pa? by mirror arrangem5ts--mak+ x possible to susp5d ! cam]a diagonally 9 ! ,am]ican & ,briti% planes1 = tak+ oblique pictures4 ,flatness ( ! film is secur$ by a suction plate cov]$ ) graphit$ clo? & connect$ ) a ,v5turi tube4 ,! top cov] is remov$ = re-load+4 ,! %utt]s on ! fir/ cam]as ( ?is type are ( ! v>iable-t5sion fix$-ap]ture design1 ?\gh lat] ones h ! v>iable-ap]ture curta9 controll$ by an idl]1 z us$ 9 ! ,am]ican de,ram4 ,an auxili>y curta9 %utt] s]ves to cap ! true %utt] dur+ sett+4 ,! op]ation ( ! film driv+ me*anism is comp>atively simple4 ,x consi/s ( a tra9 ( ge>s1 driv5 by a flexible revolv+ %aft atta*$ to "s sep>ate s\rce ( p[] capable ( spe$ v>iation4 ,! action ( ! ge>s is to move ! film1 set ! %utt] & !n expose x2 9 ! e>li] cam]as ) ! film cont9u\sly mov+4 ,9 ! fir/ cam]as con/ruct$ ! space betwe5 ! pictures v>ies z ! film rolls up1 due to ! increas+ diamet] ( ! roll4 ,9 lat] cam]as ! film roll] is dis5gag$ f ! ge>s j be=e ! %utt] is tripp$1 s t ! film /&s /ill dur+ ! exposure1 & is !n re-engag$ at a new po9t on a rat*et :eel gov]n$ by ! diamet] ( ! receiv+ roll1 :]eby ! pictures are equally spac$4 ,9 all ! cam]as1 pun* m>ks made at ! "t ( exposure enable ! limits ( ! picture to be detect$ 9 ! d>k room by t\*4 ,illu/ration3 ,,fig4 #fc4--;,film w9d+ & expos+ me*anism 9 ,g]man film cam]a4 ,v>iable spe$ is arrang$ = 9 any "o ( sev]al ways4 ,= peace-"t uses a turb9e atta*$ to ! side ( ! plane is simple & positive1 &1 provid$ x is made ( suffici5t size--:i* is n ! case ) ! "o %[n 9 ! ,figure--w give adequate spe$ regulation ^u v>y+ ! ap]ture ?r\gh :i* ! air ent]s4 ,! ,v5turi tube may be c>ri$ ^u ! same m\nt1 or a small rot>y pump c be atta*$ on ! same %aft4 ,:]e ! high w9d resi/ance ( ! turb9e is an objection ! cam]a is driv5 electrically1 by a motor act+ ?r\gh ! int]m$i>y ( a v>iable spe$ control describ$ 9 ! next *apt] 7,fig4 #fh74 ,! cam]a weighs complete ab\t =ty p\nds1 & ! film rolls ab\t f\r p\nds4 ,! latt] c be *ang$ 9 ! air )\t great difficulty provid$ ! cam]a is m\nt$ accessibly & s t ! top may be op5$4 ,,*apt] ,,xii ,,motive ,,p[] ,,= ,,a]ial ,,cam]as ,z long z circum/ances p]mit1 h& op]ation /ill rema9s ! mo/ reliable & satisfactory me?od ( driv+ a cam]a4 ,x is always available1 c be appli$ to j ! am\nt desir$1 & at ! "t & place ne$$4 ,= in/ance1 9 a magaz9e ( ! ,gaumont type 7,fig4 #dj71 :at is ne$$ is ! p]iodic application ( a v consid]able =ce r quickly1 & :ile ?is c be done q simply by h&1 no me*anism has ev5 be5 attempt$ to g ?r\gh ?is same op]ation automatically4 ,in/ead1 ! fundam5tal design ( automatic magaz9es has be5 made along o!r l9es calculat$ to utilize small] =ces m /eadily appli$4 ,x mu/ be grant$1 h[ev]1 t = w> planes1 & p>ticul>ly = s+le seat]s1 cam]as %\ld be available :i* are capable ( op]at+ semi-automatically or automatically4 ,?is necess>ily means ! employm5t ( artificial p[]1 ^: g5]ation1 transmission to ! cam]a & control z to spe$ pres5t a me*anical problem ( no small difficulty4 ,available ,s\rces ( ,p[]4--,! s\rces f :i* p[] may be drawn on ! plane are f\r1 al?\gh ! v>i\s comb9ations ( ^! pres5t a l>ge numb] ( alt]native approa*es to ! problem4 ,^! s\rces are3 #a4 ,! eng9e ( ! plane4 #b4 ,w9d motors4 #c4 ,spr+ motors4 #d4 ,electric motors4 ,^! may fir/ be consid]$ l>gely f ! descriptive /&po9t1 leav+ que/ions ( p]=mance & effici5cy = sep>ate treatm5t4 ,p[] may be d]iv$ directly f ! eng9e ?r\gh a flexible %aft1 simil> to t us$ = ! revolution c\nt]4 ,?is s\rce ( p[] is inh]5tly ! mo/ direct & effici5t1 s9ce ! eng9e is ! seat ( all ! lift+ & driv+ en]gy ( ! plane4 ,!re is no loss ?r\gh trans=mation into o!r =ms ( en]gy1 su* z electrical2 or by ! use ( m or less ineffici5t int]m$i>y app>atus1 su* z w9d propell]s4 ,aga9/ ! direct drive ( ! cam]a f ! eng9e may1 h[ev]1 be urg$ t ! usual di/ance betwe5 eng9e & cam]a is too great = reliable me*anical connection1 z by flexible %aft+4 ,objections also arise f ! /&po9t ( spe$4 ,?is _c be controll$ by ! cam]a op]ator2 & v>ies ov] too wide a range1 z ! eng9e *anges f idl+ to full spe$1 to fit x = automatic cam]a op]ation4 ,! fir/ objection may be met by t comb9ation ( me?ods ( p[] drive :i* consi/s 9 transmitt+ ! p[] electrically2 t is1 by lett+ ! eng9e op]ate a g5]ator f :i* cables run to a motor close to ! cam]a4 ,?is me?od1 ( c\rse1 sacrifices effici5cy1 & x breaks d[n :5 ! eng9e spe$ drops bel[ ! spe$ necess>y to g5]ate ! requisite voltage4 ,?is defect may 9 turn be met by float+ 9 /orage batt]ies1 :i* br+s up ! :ole "q ( electrical drive1 to be treat$ pres5tly4 ,:ile use ( ! eng9e = direct drive or = g5]at+ electric curr5t has n be5 adopt$ 9 ! ,am]ican s]vice1 x is kn[n t "s ,g]man planes 7 suppli$ ) electric curr5t 9 ?is way4 ,com+ next to ! w9d motors1 ^! possess "o v great m]it3 !y utilize a motive p[] t is always pres5t z long z ! plane is 9 motion ?r\gh ! air4 ,on ! o!r h&1 ! process ( us+ ! ma9 propell] ( ! plane to pull ano!r small] propell] ?r\gh ! air appe>s a r\ndab\t way to utilize ! driv+ p[] ( ! airplane eng9e4 ,yet on ! :ole x is probable t "s =m ( propell] or w9d turb9e is ! simple/ & mo/ conv5i5t device we h = ! op]ation ( airplane auxili>ies4 ,z long z ! am\nt ( p[] requir$ is small1 su* ineffici5cy z is inh]5t 9 its use is (fset by its conv5i5ce & reliability4 ,an advantage ( ! propell] is t its spe$ is almo/ directly proportional to t ( ! plane ?r\gh ! air1 a desirable feature 9 automatic cam]as provid$ ! proportionality is "u control4 ,yet x is j 9 ?is matt] ( v>y+ ! spe$ at w t ! propell] pres5ts difficulties1 to be met only by additional me*anisms = ge>+ d[n or gov]n+4 ,propell]s h ! practical disadvantage t !y pres5t an easily b5t or brok5 projection to ! body ( ! plane 7,figs4 #hc & #hd74 ,! /r5g? ( small propell]s = op]at+ auxili>ies is nev] s mu* 9 "q ) ref]5ce to _! resi/ance to :irl+ & ?ru/ ( air z x is to _! ability to )/& ! inevitable knocks & c>eless h&l+ t w fall to _! lot4 ,! propell] bracket is j :at ! pilot is look+ = to scrape ! mud (f 8 boots be=e climb+ 94 ,! w9d turb9e has ! advantage ov] ! propell] t its spe$ c be v>i$ r simply by expos+ m or less ( its face to ! w9d4 ,a turb9e fitt$ ) an adju/able ap]ture = admitt+ ! w9d is %[n 9 ,fig4 #fd1 9 connection ) ! type ,k automatic film cam]a4 ,! turb9e has ! advantage ( be+ compact & ly+ close aga9/ ! body ( ! plane4 ,9 ! =m figur$1 altoge!r too mu* head resi/ance is (f]$--j z mu* = l[ z = high spe$s--b ) prop] design ?is ne$ n be ! case4 ,x is1 moreov]1 q too small to give ! ne$$ spe$ regulation1 z x only beg9s to op]ate ne> its full op5+4 ,illu/ration3 ,,fig4 #fd4--,u4 ,s4 ,type 8,k0 7,folm]7 automatic film cam]a1 ) w9d turb9e & ,v5turi tube4 ,illu/ration3 ,,fig4 #fe4--,type 8,k0 cam]a1 op51 %[+ suction plate4 ,spr+ motors h ! v real advantage t by _! use ! cam]a c be made entirely self conta9$4 ,! simple/ application ( ! spr+ motor w\ld be to ! semi-automatic cam]a1 :]e no close regulation ( spe$ is requir$4 ,9 su* a cam]a ! op]ation ( expos+ ! %utt] w\ld release ! spr+1 :i* w\ld !n *ange ! plate or film & re-set ! %utt]1 repeat+ ?is op]ation z long z ! spr+ reta9$ suffici5t t5sion4 ,small film h&-cam]as ( ?is type1 us+ self-sett+ betwe5-!-l5s %utt]s1 h be5 design$1 ?\gh n = a]ial "w4 ,! possibilities ( us+ spr+s z motive p[] 9 semi-automatic cam]as h n app>5tly be5 s]i\sly consid]$4 ,:5 a spr+ motor is us$ = automatic cam]a op]ation x at once becomes necess>y to add to ! motor an elaborate clock me*anism = controll+ & regulat+ its spe$ ( action4 ,spr+s are mu* bett] fitt$ = giv+ p[] by quick release ( _! t5sion ?an by sl[ release1 & ! necess>y clock me*anisms = _! regulation become v heavy1 z well z complicat$ & delicate1 :5 !y are made l>ge en\gh to d any real "w4 ,= _! repair !y require ! s]vices ( clock mak]s r ?an ! usual m available k9d ( me*anic4 ,com+ next to electric motors1 we meet ) a s\rce ( p[] ( v great flexibility bo? 9 its d]ivation & 9 its application4 ,if a s\rce ( electric curr5t is already provid$ = heat+ & light+ z x is on ! fully equipp$ milit>y plane1 & if x has suffici5t capacity to h&le ! cam]a1 its use is r cle>ly indicat$1 irrespective ( h[ effici5tly or by :at me?od x is produc$4 ,especially is ?is ! case1 f ! /&po9t ( economy & simplicity1 if a propell]-driv5 g5]ator is ! s\rce ( curr5t1 & ! alt]native p[] drive is an additional propell] = ! cam]a4 ,if1 on ! o!r h&1 ! cam]a mu/ h its own s\rce ( electric p[]1 ! advantages & disadvantages mu/ be closely scrut9iz$4 ,9 ?is case ei!r a g5]ator mu/ be provid$1 or resort be made to /orage batt]ies1 or a comb9ation ( ! two4 ,rul+ out a special propell]-driv5 g5]ator1 we are left ) ei!r ! g5]ator driv5 f ! eng9e or ! /orage batt]y4 ,inasmu* z /orage batt]ies are practically indisp5sable ) g5]ators1 9 ord] to ma9ta9 ! voltage con/ant at all spe$s1 x is on ! :ole advisable to rely ^u batt]ies alone4 ,an advantage ( _! use is t ! p[] plant is entirely )9 ! plane3 ,all projections su* z propell]s are avoid$4 ,ano!r m]it is t ! p[] is drawn ^u only z ne$$4 ,aga9/ /orage batt]ies is _! weight1 ! ne$ = frequ5t *>g+1 & _! loss ( effici5cy at l[ temp]atures--a loss s s]i\s ) ^? ( ! ,edison =m z to preclude _! use4 ,:5 once ! s\rce ( electrical en]gy is decid$ ^u1 its me?od ( application ne$s to be consid]$4 ,"h we meet at once ! peculi> m]it ( electrical en]gy1 namely1 ! ease & conv5i5ce ) :i* x may be transmitt$4 ,all we ne$ is a pair ( wires1 l$ to any "p ( ! plane by any conv5i5t r\te & connect$ by simple b9d+ po/s4 ,x may ) equal ease be turn$ on or (f by m]ely mak+ or break+ a contact ) a swit*4 ,= op]at+ semi-automatic cam]as ?is feature may be utiliz$ 9 ! int]e/ ( economy1 if ! p[] is automatically turn$ (f z soon z ! plate-*ang+ op]ation is f9i%$4 ,exceptionally reliable make & break contacts are necess>y to insure ! success ( ?is latt] s*eme4 ,two me?ods ( trans=m+ ! supply ( electrical en]gy into me*anical motion are available4 ,! fir/ is by ! use ( a sol5oid & plung]4 ,?is is a device practically re/rict$ to semi-automatic cam]as1 9 :i* ! op]ation consi/s ( a /raight to-&-fro motion1 initiat$ at ! w ( ! op]ator4 ,x has be5 us$ little if at all4 ,! second motion is ! cont9u\s rot>y "o secur$ by ! use ( an electric motor4 ,?is motion is ! mo/ practical "o = ! cont9u\s op]ation ( any me*anism1 b on ! o!r h& requires t ! impos$ load be reasonably uni=m at all times ?r\gh ! cycle ( op]ations4 ,assum+ t ! cam]a me*anism is ( ?is "*1 ! motor may be atta*$ directly to ! cam]a1 or if x mu/ be s l>ge z to cause dang] by vibration1 x may be connect$ ?r\gh a flexible %aft4 ,?is use ( an electric motor is v practical = semi-automatic cam]as su* z ! 8,l0 or ! ,am]ican de,ram1 9 planes suppli$ ) a suitable s\rce ( curr5t4 ,:5 x comes to entirely automatic cam]as1 :]e uni=m & regulatable spe$ is requir$1 z 9 mak+ ov]lapp+ pictures = mapp+1 ! electrical drive is n s conv5i5t4 ,! %unt-w\nd motor runs at ne>ly con/ant spe$1 :ile ! s]ies-w\nd motor 9 :i* ! spe$ c be regulat$ by ! int]position ( resi/ance1 has no?+ l a suffici5t range ( v>iation = ! purpose 7at lea/ five to "o is imp]ative7 be=e x fails to c>ry ! load4 ,h5ce we mu/ ei!r incorporate 9 ! cam]a "s me*anism = v>y+ ! int]val betwe5 exposures :ile ! spe$ ( ! motor rema9s con/ant1 or introduce an auxili>y device to effect ! requir$ trans=mation 9 spe$4 ,if we d use an auxili>y device ! tra9 ( app>atus1 consi/+ ( batt]y 7or g5]ator71 motor1 spe$ control & cam]a1 is altoge!r too long2 x is apt to cause annoy+ delays 9 connect+ up 9 an em]g5cy1 & x (f]s an excessive numb] ( *ances = break-d[n4 ,p]=mance & ,effici5cy ,data4--,! fir/ /ep 9 decid+ ^u me?ods ( p[] drive1 & inde$ 9 decid+ :e!r p[] drive is feasible at all1 is to assemble def9ite data z to ! p[] requir$ to drive repres5tative cam]as4 ,approximate figures = "s ( ! cam]as describ$ 9 previ\s *apt]s are3 ,l cam]a1 #bf watts1 de,ram1 #fj watts1 8,k0 film1 #cj watts4 ,^! requirem5ts--n exce$+ horse p[]--are insignificant 9 comp>ison ) ! total ( #ajj to #djj horse p[] available = all purposes f ! plane's eng9e4 ,propell] *>act]i/ics4 ,data on ! p]=mance ( small propell]s are some:at meagre4 ,h[ev]1 ! results ( ! r ext5sive rese>*es on l>ge ones1 suitable = driv+ planes1 may be appli$1 ) prop] res]vations1 to give a fair guide to ! /udy ( ! application ( small propell]s = driv+ plane auxili>ies4 ,! fir/ factor to be consid]$ is ! ?ru/ or head resi/ance (f]$ by a propell] to motion ?r\gh ! air4 ,?is v>ies z ! squ>e ( ! velocity1 z ! d5sity ( ! m$ium1 & z ! area ( ! body project$ normally to ! w9d1 ! =mula be+ ,t cda,v#b :]e ,t ?ru/1 d d5sity1 a area1 ,v velocity4 ,data on ! ,l cam]a propell] are %[n 9 ,fig4 #ff1 :]e its ?ru/ bo? :5 free & :5 load$ ) ! cam]a is giv51 z well z t ( a solid disc ( ! same diamet] z ! propell]4 ,= ?is propell]1 :i* is d\ble-blad$1 & six in*es 9 diamet]1 cda 4#jjjbge ) ! load on4 ,! total ?ru/ am\nts to only ab\t ?ree p\nds :5 ! plane velocity is #ajj miles p] h\r4 ,! head resi/ance ( ! :ole plane is a matt] ( hundr$s ( p\nds1 s t ! propell] resi/ance is q negligible4 ,illu/ration3 ,,fig4 #ff4--,w9d propell] data4 ,! next factor is ! spe$ ( revolution ( ! propell]1 express$ 9 revolutions p] m9ute4 ,?is v>ies ) ! design--! numb] ( blades1 _! area1 & pit*4 ,= a giv5 design ! spe$ ( revolution is directly proportional to ! spe$ ( motion ?r\gh ! air1 & to ! d5sity ( ! air4 ,repres5tative data = ! ,l cam]a propell] are %[n 9 ,fig4 #fg4 ,x w be not$ t ! spe$ goes up to #hjjj = #abj miles p] h\r air spe$4 ,?is illu/rates ! necessity = great /r5g? to )/& c5trifugal =ce4 ,propell]s %\ld be con/ruct$ ( t\gh mat]ial1 & subject$ to :irl+ te/s up to spe$s consid]ably 9 excess ( any ! plane w atta9 9 any maneuv]4 ,at l[ spe$s ! l9e> relation%ip fails1 z a critical velocity is rea*$--ab\t #cejj r4 p4 m4 = ?is propell]--:]e x refuses to turn4 ,illu/ration3 ,,fig4 #fg4--,relation betwe5 air spe$ & propell] revolutions4 ,! fact t ! spe$ ( ! propell] dep5ds on ! d5sity ( ! air has an int]e/+ coroll>y1 :i* is t a propell] adequate at l[ altitudes w fail at high ones4 ,! d5sity ( ! air v>ies ) altitude accord+ to ! foll[+ figures3 ,at #cjjj met]s1 #gb p] c5t4 ( sea level #ejjj met]s1 #ei p] c5t4 ( sea level #fjjj met]s1 #eb p] c5t4 ( sea level ,if we take ! r4 p4 m4 at #ij miles p] h\r at sea level z #fjjj1 !n at ! above altitudes ! spe$s w be #dcjj1 #cejj1 & #cjjj1 respectively4 ,! la/ figure is bel[ t = :i* ?is size ( propell] /alls ) its normal load1 z not$ 9 ! la/ p>agraph4 ,consequ5tly1 if fly+ is to be done at ^! altitudes a l>g] propell] mu/ be c>ri$1 :i* w /ill deliv] en\gh p[] at ! l[] d5sity4 ,! next factor to be consid]$ is ! p[] furni%$ by ! propell]4 ,z a repres5tative figure may be quot$ ! p]=mance ( ! ,l propell]4 ,?is gives #bg watts at #cfjj revolutions p] m9ute 7#ef miles p] h\r74 ,f ?is figure ! p]=mance ( o!r propell]s may be d$uc$ f ! basic laws1 :i* are3 t ! p[] v>ies z ! d5sity ( ! m$ium & z ! cube ( ! velocity 7assum+ con/ant effici5cy74 ,s9ce ! p[] deliv]$ by ! six in* diamet] ,l propell] is already adequate at #fj miles p] h\r1 ! necess>y dim5sion to function satisfactorily at #ajj miles p] h\r w\ld ne$ to be only a little m ?an ?ree in*es1 except = ! desirability ( a safety factor = high altitudes & l[ air d5sities4 ,! effici5cy ( ! propell] is def9$ by ! relation-- p[] deliv]$ by ! propell] ,effici5cy ---------------------------------------- ------------------------ p[] suppli$ to ! propell] ,! d5om9ator ( ?is fraction is ! ?ru/ times ! velocity1 = :i* ! curves ( ,fig4 #ff supply u data = ! ,l propell]4 ,us+ ! figures #cfjj r4 p4 m41 #ef miles p] h\r1 & #bg watts1 we f9d ! effici5cy to be ab\t #ej p] c5t4 ,?is increases ) ! velocity1 ) a possible upp] limit ( #gj to #hj p] c5t4 ,s9ce ! ma9 propell] ( ! plane is n ov] #hj p] c5t4 effici5t we h at mo/ an effici5cy ( #fd p] c5t4 9 us+ a propell] drive1 z comp>$ ) tak+ ! p[] directly (f ! eng9e4 ,9 consid]+ ! use ( spr+ & clock-"w motors we meet at once ) ! problem ( comp>+ ! effect on ! p]=mance ( a plane ( a c>ri$ weight1 z aga9/ a head resi/ance4 ,! effici5cy ( a spr+ motor is measur$ 9 t]ms ( its weight1 t ( a propell] 9 t]ms ( its head resi/ance4 ,! g5]al answ] to ?is "q is giv5 by ! relation t a p\nd ( dead weight is equival5t to p\nd head resi/ance4 ,9 ord] to apply ?is relation to ! /udy ( spr+ motors = driv+ cam]as1 data are necess>y on ! p[] deliv]y p] p\nd weight ( su* me*anisms4 ,su* data are n easily accessible1 l>gely because clock-"w has n g5]ally be5 s]i\sly consid]$ z a motive p[] = l>ge app>atus4 ,to arrive at an approximate figure we may take ! fact t 9 an #h #aj in* film cam]a design$ by "o ( ! manufactur]s :o h utiliz$ clock-"w1 ! motor weigh$ #cj p\nds4 ,?is is equival5t to six p\nds head resi/ance4 ,n[ ! type ,k1 #ah #bd c5timet] film cam]a is op]at$1 ev5 ) ! addition ( a friction drive spe$ control1 by means ( ! ,l cam]a propell]4 ,z %[n 9 ,fig4 #ff1 at #ajj miles p] h\r ! head resi/ance ( ?is propell] is /ill less ?an ?ree p\nds4 ,consequ5tly1 x appe>s t f ! effici5cy /&po9t ! clock me*anism is q outclass$ by ! w9d propell]4 ,com+ next to ! electric motors1 ! ,l cam]a & ! ,k are bo? op]at$ satisfactorily ) a #a_/bj horse p[] motor1 weigh+ #f p\nds4 ,= ! de,ram a horse p[] motor has be5 adopt$4 ,tak+ up effici5cy consid]ations1 we h1 if ! curr5t is suppli$ by a g5]ator f ! eng9e1 a trans=mation factor ( #gj to #hj p] c5t4 f me*anical to electrical en]gy & a simil> factor 9 us+ a motor = ! cam]a4 ,:5 batt]ies are employ$ ! matt] ( weight v]sus head resi/ance aga9 arises4 ,! batt]ies f\nd mo/ satisfactory = op]at+ ! ,k & de,ram cam]as are ( ! six-cell #ab volt lead type4 ,_! capacity is #dj ampre h\rs at ?ree ampres or #cf at five ampres--m ?an is necess>y = a s+le reconnaissance1 b a practical figure :5 economy ( *>g+ & replacem5t are consid]$4 ,! weight ( ?is unit is #bg p\nds4 ,to ?is mu/ be add$ ! weight ( ! motor--#f lbs4--mak+ a total ( #cc p\nds1 equival5t to a head resi/ance ( ne>ly #g p\nds4 ,?is is m ?an twice ! propell] head resi/ance invok$ to d ! same "w4 ,^! consid]ations ( effici5cy h be5 gone into because !y are usual 9 /udy+ any eng9e]+ problem & because ( ! insi/5t dem& f ! plane design] t e ounce ( weight & head resi/ance be sav$4 ,actually1 z already /at$1 ! load impos$ by any me?od ( p[] drive is trivial 9 comp>ison ) ! :ole load ( ! plane4 ,!re is1 h[ev]1 an important res]vation to be made1 :i* applies aga9/ clock-"w & batt]ies3 ,?is is1 t :ile ! equival5t head resi/ance ( any cam]a motive p[] c>ri$ z dead weight is small1 its effect on balance may n be s4 ,:ile ! use ( a propell] ne$ n di/urb ! plane's balance1 ! weight ( ! cam]a alone1 )\t any driv+ app>atus1 is already s]i\sly object$ to on ?is score4 ,! m]ely me*anical sup]iority ( ! propell] z a s\rce ( motive p[] is on ! :ole r m>k$4 ,control ( ,cam]a ,spe$4--,9 ! semi-automatic cam]a ! only control requir$ on ! spe$ ( ! op]at+ motor is at ! upp] & l[] limits4 ,x mu/ n g s fa/ z to anticipate ! completion ( any /eps 9 ! cycle ( cam]a op]ation1 su* z ! fall ( plates or pawls into position1 :i* w\ld jam ! cam]a4 ,on ! o!r h&1 x mu/ n be s sl[ t pictures _c be obta9$ ) ! requisite ov]lap = maps or /]eoscopic views4 ,9 ! ,am]ican de,ram cam]a ! cycle ( op]ations _c safely be put ?r\gh 9 less ?an f\r seconds1 a %ort en\gh int]val = mo/ purposes4 ,x is also highly desirable 9 ! semi-automatic cam]a to h ! motive p[] capable ( /opp+ completely4 ,?is saves we> & te> on bo? motor & cam]a me*anism4 ,9 ! automatic cam]a an extreme range ( spe$ is call$ = by ! sev]al problems ( mapp+1 oblique photography1 & ! mak+ ( /]eoscopic views4 ,= mapp+ alone1 ! %orte/ likely int]val may be tak5 z t requir$ = "w at approximately #ajjj met]s altitude1 = a plane spe$ ( #aej kilomet]s p] h\r1 :i* dem&s an int]val ( six seconds ) a t5 in* l5s on a #d #e in* plate4 ,= v]tical /]eos at ! same altitude & spe$ ?is int]val is divid$ by ?ree1 & l[ oblique /]eos ne$ ev5 quick] op]ation4 ,h5ce a range ( f #a to #cj pictures p] m9ute %\ld be provid$ =4 ,?is requirem5t is difficult to meet ) any simple me*anism4 ,f ! /&po9t ( simplicity 9 spe$ regulation ! w9d turb9e ( adequate vane surface has mu* to recomm5d x4 ,x is only necess>y to pres5t m or less ( its vane area to ! w9d 9 ord] to secure a consid]able range ( spe$4 ,! me?od ( do+ ?is by a %utt] int]pos$ 9 front is uneconomical1 b x is probable t ! design c be s alt]$ t m or less ( ! turb9e is expos$ beyond ! side ( ! plane1 possibly by v>y+ ! angle1 to secure ! same result )\t introduc+ useless head resi/ance4 ,a s]i\s practical objection to ! turb9e lies 9 ! l>ge vane surface necess>y to give adequate p[] comb9$ ) prop] spe$ v>iation4 ,9 ! automatic film cam]a 7,type ,k7 ?is area %\ld be z mu* z #dj to #ej squ>e in*es4 ,! w9d propell] does n l5d itself at all well to spe$ v>iation4 ,x _c be p>tially cov]$ f ! air /ream1 z c ! turb9e1 because ( ! result+ /ra9 on its m\nt4 ,a possible =m ( v>iable spe$ propell]1 "o :i*1 h[ev]1 has n yet be5 practically develop$1 is a propell] ) controllable v>iable pit*4 ,if ?is c\ld be made me*anically s\nd x w\ld be well-suit$ = cam]a op]ation4 ,t su* a propell] c\ld be work$ out is indicat$ by ! good p]=mance ( a con/ant spe$ propell] develop$ = radio g5]ators & us$ on ! ,fr5* de,ram cam]a 7,fig4 #ed74 ,p>5!tically1 x maybe que/ion$ :e!r a con/ant spe$ propell] is really desirable ) an airplane cam]a4 ,:at is requir$ is n exposures at a def9ite "t int]val--al?\gh mo/ ( ! data are 9 t =m--b exposures at def9ite int]vals ) respect to ! motion ( ! plane1 :i* practically means ) ref]5ce to its air spe$4 ,r ?an build a cam]a calculat$ to give exposures at int]vals ( s _m seconds :5 x is atta*$ to a con/ant spe$ propell]1 we w\ld d bett] to use a propell] :i* responds to ! spe$ ( ! plane1 9 conjunction ) "s =m ( ta*omet] to %[ ! rate at :i* exposures are be+ made4 ,?is 9 turn %\ld be cord9at$ ) ! indications ( a prop] cam]a-field indicat+ sight4 ,"o solution ( ! problem ( spe$ control ) a propell] ( practically fix$ spe$1 is to use a gov]nor & slip clut* z 9 ! ,engli% ,type ,f film cam]a 7,fig4 #eg74 ,"h ! propell] %aft & ! cam]a driv+ axle are connect$ by two friction discs4 ,t on ! cam]a me*anism is =c$ aga9/ ! o!r by a spiral spr+1 ^: t5sion is controll$ by a ball gov]nor4 ,if ! cam]a spe$ becomes too high ! gov]nor r$uces ! t5sion on ! spiral spr+ & ! discs slip ov] ea* o!r4 ,! po9t :]e ?is slipp+ occurs is det]m9$ by ! position ( ! gov]nor z a :ole1 & ?is is controll$ by a lev] on top ( ! cam]a4 ,ano!r spe$ control device1 p]haps m positive b c]ta9ly m complicat$ & wa/eful ( p[]1 consi/s ( a l>ge flat disc1 driv5 by ! propell] or electric motor1 & f :i* ! cam]a is driv5 by a %aft f a small] friction disc :i* may be press$ aga9/ any po9t f ! c5t] to ! p]iph]y ( ! l>g] disc4 ,! spe$ range atta9able 9 ?is way is limit$ only by ! size ( ! l>ge disc4 ,an application ( ?is idea is %[n 9 ! spe$ control 7,fig4 #fh71 design$ = ! ,am]ican ,type ,k cam]a :5 op]at$ on an electric motor or on a simple propell]4 ,! same idea is utiliz$ 9 ! ,du*atelli] film cam]a1 9 connection ) ! con/ant spe$ propell] already describ$4 ,illu/ration3 ,,fig4 #fh4--;,friction disc spe$ control4 ,on ! :ole x is em95tly desirable f ! /&po9t ( p[] op]ation t ! automatic cam]a %\ld embody its own means = alt]+ ! int]val betwe5 exposures1 s t all ! ext]nal atta*m5t ne$$ is a s+le connection to a s\rce ( p[] ei!r ( con/ant spe$1 z an electric motor1 or ( spe$ proportional to t ( ! plane1 z ) a simple w9d propell]4 ,?is makes ! cam]a l>gely indep5d5t ( ! nature ( ! p[] supply1 :]eas a cam]a design$ = a special v>iable spe$ device is ( little use on a plane :]e ?is is n available4 ,transmission ( ,p[] to ! ,cam]a--,x has already be5 po9t$ out t ! ease ( transmission ( electrical en]gy makes x p>ticul>ly conv5i5t = use 9 a plane4 ,all o!r s\rces ( p[]1 except clock-"w incorporat$ 9 ! cam]a1 require flexible %aft+1 s t ! "q ( be>+s & connections becomes a s]i\s "o1 especially :5 ! %aft runs cont9u\sly = long p]iods at v high spe$s4 ,! %aft+ f\nd mo/ suitable is ! spirally w\nd =m commonly kn[n z d5tal %aft+4 ,?is mu/ be encas$ 9 a smoo?ly fitt+ %ea?1 flexible en\gh to p]mit ( easy b5ds4 ,! ends ( ! %aft %\ld be equipp$ ) squ>e or rectangul> p9s to fit into correspond+ slots 9 ! motor & cam]a %afts4 ,! ends ( ! %aft cas+ may be fitt$ ei!r to atta* by bayonet jo9ts or by smoo?ly fitt+ screw coll>s4 ,at ! po9t ( atta*m5t to ! cam]a x is desirable to h "s =m ( junction adju/able z to ! direction f :i* ! %aft may be connect$1 s t x ne$ be b5t z little z possible4 ,a "r angle bevel ge> (f]s "o means ( do+ ?is4 ,be>+s1 su* z ^? ( ! propell]1 %\ld be ( ! ball v>iety1 :ile heavy lubrication1 su* z vasel9e1 %\ld be freely us$1 bo? 9 ! be>+s & 9 ! %aft cas+4 ,an important feature ( any p[] drive sy/em %\ld be a safety device1 s t ! p[] w race 9 case ( any jam or /oppage 9 ! cam]a4 ,?is w (t5 prev5t s]i\s damage ?r\gh ! breakage ( "s relatively weak "p ( ! cam]a me*anism on :i* ! :ole =ce ( ! driv+ app>atus is sudd5ly ?r[n4 ,! 8,l0 cam]a propell] is fitt$ ) a spr+ friction clut* ) ! idea t if ! cam]a refuses to op]ate ! propell] w slip in/ead ( wr5*+ ! %aft to pieces4 ,,*apt] ,,xiii ,,cam]a ,,auxili>ies ,di/ance ,controls & ,indicators4--,all op]ations connect$ ) ! expos+ & *ang+ ( plates 7except ! *ang+ ( :ole magaz9es7 %\ld be arrang$ = accompli%m5t at a di/ance4 ,o!r op]ations1 su* z *ang+ ! %utt] spe$ or ! int]val betwe5 exposures 9 an automatic cam]a1 :i* are usually done on ! gr\nd1 may sometimes be satisfactorily left = p]=mance at ! cam]a4 ,conditions ( extreme inaccessibility may1 h[ev]1 make x necess>y to c>ry ev5 ^! controls to a di/ance4 ,indicators ( ! numb] ( exposures already made1 & ( ! read9ess ( ! cam]a = ! next exposure1 may be atta*$ to ! cam]a1 b (t5 are m pr(itably plac$ at a di/ance4 ,di/ance control & indication are especially necess>y if ! pilot makes ! exposures--a common ,engli% practice 9 two seat]s1 & ! only rec\rse 9 s+le seat]s4 ,:5 electric p[] is available1 electrical di/ance control devices are p]haps ! simple/ k9d1 z !y transmit motive p[] )\t displac+ or j>r+ ! cam]a4 ,sol5oids suffice = ! simple press+ ( releases or = c\nt+ me*anisms1 :ile small s]vice motors may be utiliz$ = op]ations involv+ m "w4 ,a /&+ practical objection to electrical control lies 9 ! necessity = us+ contacts1 :i* are apt to be unc]ta9 "u conditions t involve vibration4 ,! ,b[d5 wire--a wire cable c>ri$ inside a heavy non-ext5sible b flexible %ea?--con/itutes ! mo/ satisfactory me*anical means = transmitt+ /raight pulls4 ,by means ( 8! ,b[d50 a pull may be transmitt$ s z to be made entirely relative to two p>ts ( ! same body1 call+ =? no t5d5cy ( ! body z a :ole to move4 ,?us 9 ! ,l cam]a %utt] release 7,fig4 #ej71 ! releas+ lev] ) its atta*$ c\nt] is sev]al feet di/ant f ! cam]a4 ,if ! plate be>+ ! lev] & %ea? end is rigidly fa/5$ d[n1 ! pressure ex]t$ on mov+ ! lev] acts betwe5 ! lev] & ! end ( ! %ea?4 ,?is pressure passes imm$iately to ! o!r end ( ! %ea?1 :ile ! pull on ! wire is transmitt$ to its f>!r end on ! cam]a4 ,9 ?is way ! conditions at ! lev] are reproduc$1 b ) ! advantage t1 due to ! flexible cable & %ea?1 any vibration ( ! lev] support is damp$ out4 ,due to its /ret*+1 !re is a pretty def9ite limitation to ! feasible l5g? ( ! ,b[d5 wire4 ,?is l5g? is ab\t f\r feet4 ,:]e accord+ to ,engli% practice ! pilot makes ! exposure1 a consid]ably long] wire & %ea? are call$ =4 ,9 ?is case ! effective l5g? ( ! release is increas$ by giv+ ! pilot a second releas+ lev]1 connect$ to ! fir/ by a rigid rod 7,fig4 #fi74 ,! releas+ lev]1 wire1 & all me*anical p>ts ( ! ,b[d5 release %\ld be made mu* /rong] ?an w\ld be indicat$ by b5* te/s ( ! cam]a4 ,9 ! air x is impossible to decide ei!r by s\nd or by delicacy ( t\* :e!r ! me*anism has act$1 s t ! obs]v] is apt to pull mu* h>d] ?an necess>y & to /ra9 or break ! release if x is weak4 ,! ,b[d5 wire is us$ 9 ! ,am]ican s]vice only = %utt] release4 ,9 ! ,engli% s]vice x has be5 us$ = plate *ang+ ) ! ,l cam]a4 ,illu/ration3 ,,fig4 #fi4--;,b[d5 wire release 9 re> cockpit1 ) rod connect$ to simil> release = ! pilot4 ,illu/ration3 ,,fig4 #gj4--;,b[d5 wire release ) /op wat* atta*$1 = use 9 tim+ = ov]laps4 ,sights4--,9 airplane photography ! ne$ = a f9d] or sight is fully z great z 9 ev]yday "w4 ,a new condition1 h[ev]1 prevails1 = except ) h&-held cam]as1 & ev5 to "s ext5t ) !m1 ! op]ation ( po9t+ ! cam]a involves po9t+ ! :ole vehicle t c>ries ! cam]a4 ,! po9t+ ( airplane cam]as is !re=e ak9 to ! sight+ ( great guns4 ,:ile ! obs]v] may p]=m ! actual op]ation ( tak+ ! picture1 ! responsibility = cov]+ ! objective re/s ) ! pilot4 ,teamwork c\nts equally ) tools4 ,airplane cam]a sights may accord+ly be divid$ into two classes3 sights atta*$ to ! cam]a1 = use pr9cipally ) h&-held app>atus1 & sights atta*$ to ! plane1 = ! use ( pilot1 ( obs]v]1 or ( bo?4 ,sights = ,h&-held ,cam]as4--,! simple/ =m ( sight atta*$ directly to ! cam]a is model$ on ! gun sight1 consi/+ ( a =w>d po9t or bead & a re> ,v4 ,?is sight ( c\rse s]ves m]ely to place ! objective 9 ! c5t] ( ! plate & gives no indication ( ! size ( field cov]$4 ,ano!r simple sight ( r bett] type is ! tube sight--a metal tube ( approximately "o in* diamet] & ?ree in*es l5g?1 c>ry+ at ea* end pairs ( wires cross$ at "r angles4 ,! cam]a is 9 alignm5t :5 ! front & back cross wires bo? exactly mat* on ! object to be photograph$4 ,! be/ way to m\nt ! cross-wires is ) "o pair turn$ ?r\gh #de degrees ) respect to ! o!r1 s t x is at once app>5t :i* is ! front & :i* ! re> pair 7,figs4 #ca & #ci74 ,sights to indicate ! size ( ! field are usually less ne$$ on h& cam]as ?an on fix$ v]tical cam]as4 ,yet c]ta9 circum/ances make !m mo/ desirable1 = in/ance 9 naval "w :]e a complete convoy mu/ be includ$ on ! plate4 ,a sight ( ?is k9d c be made up ( two wire or /amp$ metal rectangles1 a l>ge "o 9 front & a small] "o beh9d1 ( su* relative sizes & sep>ations t ! true cam]a field is outl9$ :5 ! eye is plac$ 9 position to see ! two rectangles j cov] ea* o!r4 ,! dim5sions %\ld be s *os5 t ! correct position ( ! eye is approximately its natural location ) respect to ! cam]a :5 ?is is held 9 ! h&s 9 ! plane4 ,x is usual to provide ! rectangul> sights ) cross-wires to indicate ! c5t] ( ! field4 ,alt]native re> sights are simple beads or peep-holes--! use ( ! bead assum+ t ! cam]a is held at ab\t ! "r di/ance f ! eye = ! rectangle to indicate ! field4 ,! peep-sight is n a desirable =m1 z x is h>d to hold ! cam]a z ne> ! face z is necess>y4 ,^! v>i\s types ( rectangle sights are well illu/rat$ 9 ! cam]as %[n 9 ,figs4 #ch1 #dj & #ahf4 ,!y are all made s z to fold d[n flat on ! cam]a & to snap quickly op5 :5 ne$$4 ,! spr+s to support ! sights mu/ be fairly /rong1 & ! surface pres5t$ to ! w9d z small z possible4 ,wire frames give v little f ! pressure ( ! w9d1 b flat metal frames are apt to be b5t back4 ,! position ( ! sight on ! cam]a is important4 ,if ! obs]v] c /&1 or if he sits up well above ! edge ( ! cockpit1 ! conv5tional position ( ! sight on a pi/ol1 namely1 on top1 is unobjectionable4 ,b if ! obs]v] sits v l[1 z he usually does1 !n ! sight %\ld be on ! bottom ( ! cam]a1 !reby avoid+ any ne$ = ! obs]v] to raise 8 head unduly into ! slip /ream4 ,simil>ly1 if ! cam]a is us$ ov] ! side = v]ticals1 z x is 9 fly+ boats1 a sight on ! top is impractical1 s9ce x requires ! obs]v] to lean out dang]\sly f> 7,fig4 #ahe74 ,sights ,atta*$ to ! ,plane4--,any ( ! sights j describ$ c be atta*$ to cam]as fix$ 9 ! plane1 b !y w\ld be useless 9 ! positions ord9>ily occupi$ by ! cam]a4 ,x has !re=e become common practice to atta* ! cam]a sight to "s accessible "p ( ! plane4 ,! mo/ primitive me?od ( sight+ is m]ely to look d[nw>d ov] ! side--a me?od 9 g5]al use to ! v end ( ! ,great ,w>4 ,"o /ep 9 advance ( ?is is to m>k a l>ge inv]t$ ,v on ! side1 ) its v]tex at a po9t :]e ! obs]v] c place 8 eye & s see ! =e & aft ext5sion ( ! field ( view cov]$ by ! cam]a4 ,?is k9d ( sight 0 common on ! ,fr5* 8photo0 planes4 ,on "s ( ! ,engli% planes ! tube sight 0 c>ri$ on ! outside ( ! cockpit4 ,any ( ! sights describ$ c be c>ri$ on ! inside ( ! fuselage1 provid$ a hole is cut 9 ! floor4 ,= satisfactory sight+ a hole 9 ! floor is really necess>y1 z x enables ! t]ra9 on bo? sides ( ! v]tical to be se54 ,"o drawback to ! simple hole1 h[ev]1 is t x _c be made l>ge en\gh to %[ ! :ole field f ! ord9>y height ( ! obs]v]'s eye1 ?us =c+ him to br+ 8 head d[n ne> ! floor4 ,?is difficulty is gott5 ov] 9 a v beautiful way by ! use ( ! negative l5s sight %[n diagrammatically 9 ,fig4 #ga4 ,illu/ration3 ,,fig4 #ga4--;,diagram ( negative l5s sight4 ,let ,f#a be ! di/ance at :i* ! edge ( ! hole 7or a rectangle m>k$ on ! l5s7 appe>s ! size ( ! cam]a field 7if ! hole is ! size ( ! plate1 ,f#a is ! focal l5g? ( ! cam]a l5s74 ,let ,f#b be ! di/ance f ! floor to ! obs]v]'s eye4 ,:at is desir$ is a concave l5s :i* w div]ge ! rays f _! normal meet+ po9t at ,f#a to a new meet+ po9t1 ,f#b4 ,! focal l5g? ( l5s requir$ is giv5 at once by ! simple l5s =mula-- #a #a #a -------------- - -------------- ------ ,f#a ,f#b ,f ,?us if ,f#a is #ab in*es1 & ,f#b is #cf in*es1 ,f w be #ah in*es4 ,! l5s is to be m>k$ ) a rectangle %[+ ! %ape & size ( ! cam]a field1 & a c5tral m>k su* z a cross4 ,an upp] rectangle1 or a bead1 or a pair ( cross wires a few in*es bel[ ! l5s1 may be us$ = ! o!r sight4 ,= precision "w ! sight above or bel[ ! l5s %\ld be adju/able 9 position1 especially :]e ! cam]a susp5sion p]mits ! cam]a to be adju/$ = ! angle ( incid5ce ( ! plane4 ,a negative l5s sight %\ld be plac$ 9 ! obs]v]'s cockpit1 if he takes ! pictures1 & also 9 ! =w>d cockpit1 s t ! pilot may be accurately guid$ 9 8 "p ( ! task4 ,9 addition1 x is advisable to place a negative l5s well =w>d 9 ! pilot's cockpit1 to enable him to see ! c\ntry "s di/ance ahead4 ,! l5ses %\ld be planoconcave ) ! flat side upw>d2 o!rwise1 all ! loose dirt 9 ! airplane settles 9 ! middle ( ! concave depression4 ,a negative l5s sight 9 a metal frame =m+ a completely self-conta9$ unit ready = m\nt+ 9 ! plane is %[n 9 ,figs4 #gb & #gc4 ,devices = ,record+ ,data on ,plates4--,numb]+ devices4 ,! numb] ( ! cam]a is impress$ on negatives tak5 ) ! ,am]ican ,l cam]a ?r\gh ! ag5cy ( a small transp>5t corn] ( celluloid4 ,x w\ld be entirely possible to incorporate a rotat+ disc :i* %\ld turn by ! op]ation ( plate *ang+ & c>ry a s]ies ( numb]s1 s t ea* exposure c\ld be numb]$ s]ially4 ,numb]+ ( individual plates is m commonly done by holes1 not*es1 or ev5 num]als1 9 ! turn$ ov] portion ( ! %ea?s1 :i* are !n record$ photographically :5 a picture is tak5 7,fig4 #ge74 ,! *ief objection to ?is me?od is ! difficulty ( keep+ ! %ea?s toge!r 9 sets1 especially z individual ones become damag$ or lo/4 ,9 practice !re is also dang] ( ! %ea?s be+ c>elessly load$ 9 wrong ord]4 ,illu/ration3 ,,fig4 #gb4--,negative l5s & m\nt1 view$ f above4 ,! m ambiti\s idea ( record+ on ! plate all ! in=mation giv5 by ! in/rum5t bo>d ( ! plane occurs indep5d5tly & spontane\sly to all a]ial photographic map mak]s4 ,^! ideas v>y f attempts to photograph ! actual in/rum5t bo>d on e plate--a difficult task inde$ ) ! in/rum5ts & cam]a plac$ z !y are 9 ! ord9>y plane--to ! incorporation ( compass1 altimet]1 & incl9omet] 9 ! cam]a itself4 ,figure #eh %[s ! plan adopt$ 9 ! ,engli% ,f type film mapp+ cam]a already describ$1 = photograph+ a compass & an altimet] on ! film4 ,"h ! comb9$ compass & altimet] dial is above ! cam]a1 & is m\nt$ 9 a cell ) a glass bottom4 ,bel[ x is a l5s focuss+ ! ne$les & compass po9ts on ! plane ( ! film4 ,! light = photography is furni%$ by a diffusely reflect+ :ite surface on top ( ! cam]a1 illum9at$ by ! sky4 7,! cam]a 0 c>ri$ outbo>d47 ,9 ,fig4 #ef is %[n a picture ) ! compass image impress$ ^u x4 ,illu/ration3 ,,fig4 #gc4--,negative l5s & m\nt1 side view4 ,figure #gd %[s a type ( incl9ation indicator f\nd 9 "s captur$ ,g]man cam]as4 ,x consi/s ess5tially ( two small p5dulums or plumb-bobs2 "o to indicate lat]al1 ! o!r longitud9al incl9ation1 arrang$ to be photograph$ 9 silh\ette on ! plate1 z %[n 9 ! l[] "p ( ! diagram & 9 ! pr9t f a captur$ negative 7,fig4 #ge74 ,illu/ration3 ,,fig4 #gd4--;,diagram ( incl9omet] us$ 9 "s ,g]man cam]as4 ,illu/ration3 ,,fig4 #ge4--,photograph made ) ,g]man cam]a1 %[+ incl9omet] record1 f\r po9ts = locat+ diamet]s & c5t] ( plate1 & 7upp] "r-h& corn]7 numb] ( ! plate %ea?4 ,bo? ^! devices suff] f ! defici5cies ( ! in/rum5ts !y photograph4 ,! compass & ! incl9omet]1 z already m5tion$ 9 ! discussion ( airplane in/rum5ts1 only behave normally 9 /raight-away fly+1 fail+ to indicate correctly :5 ! plane is subject to accel]ations 9 any direction4 ,9 g5]al all attempts to record directional data 9 ! cam]a are ( little promise1 unless ei!r ! in/rum5ts or ! cam]a are automatically held level by "s gyroscopic device4 ,if ! in/rum5ts are s controll$1 r elaborate means = photograph+ !m are necess>y4 ,if ! cam]a is /abiliz$1 ! incl9omet]s are unnecess>y1 & ! compass behaves rationally4 ,ano!r s*eme = indicat+ incl9ations1 :i* is n subject to ! above objections1 is to photograph ! horizon ei!r on a sep>ate film or on ! same s5sitive surface1 simultane\sly ) ! pr9cipal exposure4 ,! difficulty "h is ! practical "o t x is only feasible 9 localities ( great atmosph]ic cle>ness4 ,ord9>ily1 especially any:]e ne> ! sea-coa/1 ! horizon is too r>ely se5 to be a reliable m>k 7,fig4 #d74 ,x is possible1 h[ev]1 t ?is objection c\ld be ov]come by ! use ( specially r$ s5sitive plates & suitable color filt]s1 z discuss$ 9 ! *apt] on 8,filt]s40 ,! me?od w\ld 9 any case be useless 9 m\nta9\s c\ntry4 ,! difficulties discuss$ ) ref]5ce to direction indicat+ in/rum5ts ( c\rse d n hold ) ! altimet]4 ,ord9>ily1 ?\gh1 ! altitude *anges sl[ly en\gh to p]mit ( suffici5tly accurate records be+ made by p5cil & pad4 ,= high precision map mak+ a photographic record ( altimet] read+s has a legitimate claim4 ,z we h se51 a small altimet] is incorporat$ 9 ! ,engli% ,f cam]a1 b ! bulk :i* a really precision altimet] w\ld assume w\ld be a b> to its use 9 ?is way4 ,a "t or s]ial numb] record on ! plate or film1 syn*roniz$ ) a simil> record on ! film ( an auxili>y cam]a :i* photographs ! altimet] & o!r in/rum5ts1 may be ! simple/ way to pres]ve ! majority ( ! desir$ data4 ,devices = ,heat+ ! ,cam]a4--,p>ts ( ! cam]a me*anism :i* dep5d on ! uni=mity ( action ( spr+s or ^u adequate lubrication are susceptible to *ange ) v>iation ( temp]ature4 ,at high altitudes l[ temp]atures are met :i* may freeze ord9>y ma*9e oils or may cause spr+s to s]i\sly alt] _! t5sion1 ev5 to break4 ,to meet ?is difficulty1 & probably also to dispel ! occasional cond5sation ( moi/ure on ! optical p>ts1 ! ,g]man cam]as are equipp$ ) an electrical heat+ coil plac$ j bel[ ! %utt]1 & arrang$ to connect ) ! g5]al heat+ & light+ curr5t ( ! plane4 ,two contacts are ord9>ily provid$1 = (fsett+ ! effects ( temp]atures ( -#ae & -#cj degrees c5tigrade4 ,an additional function ( ?is heat+ coil is p]haps to ma9ta9 ! s5sitiv5ess ( ! plates or film4 ,,iii ,,! ,,susp5sion ,,& ,,in/allation ,,( ,,airplane ,,cam]as ,,*apt] ,,xiv ,,!ory ,,& ,,exp]im5tal ,,/udy ,,( ,,me?ods ,,( ,,cam]a ,,susp5sion ,g5]al ,!ory4--,9 addition to ! limitation ( exposure set by ! gr\nd spe$ ( ! plane ano!r limitation is set by ! vibration ( ! cam]a4 ,?is may be caus$ ei!r by ! motor1 or by ! ela/ic reactions ( ! plane memb]s to ! /ra9s ( flight4 ,unlike ! movem5t ( ! image due to ! simple motion ( ! plane1 movem5ts due to vibration may be elim9at$ by prop] anti-vibrational m\nt+ ( ! cam]a4 ,! effect ( vibration may %[ z an indi/9ctness ( ! :ole image--?is is its only effect ) a betwe5-!-l5s %utt]--or z a b& or b&s ( indi/9ctness p>allel to ! curta9 op5+ 7,fig4 #gf74 ,^! are due to %ocks or %ort p]iod vibrations dur+ ! passage ( ! focal-plane %utt]4 ,! obvi\s rem$y = vibration tr\bles is to m\nt ! cam]a on "s ela/ic1 heavily damp+ support1 l sponge rubb] or metal spr+s4 ,su* a m\nt+ %\ld1 h[ev]1 be design$ on s\nd pr9ciples d]iv$ f a prop] analysis ( ! nature & effect ( ! possible motions ( ! cam]a4 ,o!rwise1 ! vibrational di/urbances may be increas$ r ?an dim9i%$ by ! cam]a m\nt4 ,su* an analysis1 bas$ m]ely on g5]al me*anical pr9ciples1 %[s t all motions ( ! cam]a are resolvable into six4 ,^! are ?ree translational motions1 namely1 two at "r angles 9 "o plane su* z ! horizontal1 & "o 9 ! plane at "r angles to ?is 7v]tical72 & ?ree rotational motions1 "o ab\t ea* ( ! above directions ( translational motion z an axis 7,fig4 #gg74 ,illu/ration3 ,,fig4 #gf4--;,captur$ ,g]man photograph1 %[+ zones ( poor def9ition due to vibration dur+ passage ( focal plane %utt] ap]ture4 ,brief consid]ation w %[ t only ! latt]--! rotational motions--are ( any importance :5 ! small displacem5ts due to vibration are 9 "q4 ,to illu/rate ! negligible effect ( vibrations :i* m]ely move ! cam]a p>allel to itself 9 any direction x is only necess>y to imag9e ! cam]a mov$ p>allel to ! gr\nd ?r\gh a l>ge di/ance1 su* z #aj c5timet]s4 ,n[ #aj c5timet]s motion ( ! cam]a at #cjjj met]s elevation means1 ) a #be c5timet] cam]a l5s1 4#be #a -------- #aj -------- c5timet] #cjjj #abjj motion on ! plate1 :i* w\ld be only a t5? ! di/ance sep>able by a good l5s4 ,if we r$uce ?is motion to ! small fraction ( a c5timet] :i* vibration w\ld actually produce1 x is evid5t t su* vibration is ( absolutely no importance4 ,simil>ly1 if we imag9e ! cam]a1 "u ! same conditions1 mov$ v]tically ) ref]5ce to ! gr\nd by t5 c5timet]s1 ! scale ( ! picture w\ld m]ely be *ang$ by #a_/abjjj or by #a_/ajjj c5timet] on a #ab c5timet] plate1 aga9 q negligible4 ,:5 we consid] motions ( rotation1 h[ev]1 ! case is q diff]5t4 ,if ! cam]a is m\nt$ s t ! effect ( any vibration is to rotate x ar\nd a horizontal axis1 ?is is exactly equival5t to rotat+ ! beam ( light f ! l5s s t x sweeps across ! plate4 ,?us a millimet] displacem5t ( ! l5s ( ! cam]a ) ! plate rema9+ fix$ gives approximately a millimet] motion ( ! image4 ,consequ5tly1 a rotation produc+ only a fraction ( a millimet]'s relative motion ( l5s & plate dur+ ! p]iod ! curta9 ap]ture is ov] a giv5 po9t w\ld cause fatal blurr+--& ! visible vibration ( plane long]ons & cross memb]s is easily ( half millimet] amplitude or m4 ,r$uc$ to angul> units x is easily %[n t a rotation ( "o degree p] second--:i* is q sl[ z plane oscillations g--is beyond ! limits ( tol]ation4 ,translational motions ( l>ge amplitude may be all[$1 b ! m\nt+ ( ! cam]a mu/ n p]mit ^! translations to be at all diff]5t = diff]5t p>ts ( ! cam]a4 ,illu/ration3 ,,fig4 #gg4--;,diagram %[+ possible motions ( ! airplane cam]a3 ?ree ( translation & ?ree ( rotation1 & _! comb9ations4 ,! prop] way to elim9ate vibrational effects is to devise a m\nt+ t w transmit only ! translational %ocks or t w trans=m ! rotational ones into translations4 ,plat=ms pivot$ & cross-l9k$ s z to be free to move only p>allel to !mselves 7describ$ 9 ! next *apt]7 repres5t "o attempt to rea* ?is result4 ,q ! simple/ & mo/ sci5tific =m ( m\nt+ to a*ieve ?is end is to support ! cam]a solely 9 ! plane ( ! c5t] ( gravity4 ,! pr9ciple "h involv$ is easily grasp$ if we note t :5 we j> a cam]a support$ above or bel[ its c5t] ( gravity1 ! effect is to />t ! cam]a vibrat+ ) ! c5t] ( gravity oscillat+ p5dulum-l ab\t ! po9t ( support4 ,! clos] ! c5t] ( gravity to ! c5t] ( support1 ! small] ! mom5t ( ! body ab\t ! latt] po9t4 ,exp]im5tal ,/udy ( ,me?ods ( ,cam]a ,support4--,conclusive evid5ce z to ! m]its ( any sy/em ( cam]a m\nt+ c be obta9$ only "u conditions t elim9ate ! effect ( o!r v>iables :i* may be equally efficaci\s 9 dim9i%+ ! effects ( vibration1 b :i* h only limit$ application4 ,v brief exposures--#a_/ejj second & less--w1 = in/ance1 result 9 good pictures ) almo/ any condition ( vibration4 ,h5ce a %>p picture (f]s no pro( ( ! m]its ( a cam]a m\nt+ unless x is kn[n t ! exposure 0 no %ort] ?an ! limit set by ! gr\nd spe$ ( ! plane4 ,9 fact x may be said t ! *ief object ( /udy+ me?ods ( cam]a susp5sion is to increase ! all[able exposure to a maximum1 ?us l5g!n+ ! work+ h\rs & multiply+ ! useful work+ days = a]ial photography4 ,! mo/ satisfactory me?od ( te/ yet develop$ is to fly ov] a light or a gr\p ( lights on ! gr\nd ) ! cam]a %utt] op54 ,9 ! fir/ use ( ?is me?od1 :i* orig9at$ 9 ! ,engli% ,s]vice1 su* flights 7 made at night1 b lat] x 0 f\nd t good results c\ld be got by plac+ ! lights 9 a =e/ & mak+ ! te/s :5 ! sun 0 fairly l[4 ,"o ( ! gr\p ( lights mu/ be p]iodically int]rupt$1 at a kn[n rate1 to furni% ! "t int]vals4 ,illu/ration3 ,,fig4 #gh4--,te/s ( cam]a m\nt+1 made by fly+ ov] a bright light aga9/ a d>k backgr\nd4 7a7 ,rigid fa/5+ on side ( plane2 7b7 held 9 ! h&1 inexp]i5c$ obs]v]2 7c7 held 9 ! h&1 exp]i5c$ obs]v]2 7d7 cam]a m\nt$ at c5t] ( gravity on gimbals b$d$ 9 sponge rubb]4 ,"s *>act]i/ic 8trails0 obta9$ by ?is me?od ( te/ are %[n 9 ,fig4 #gh4 ,! fir/ trail is t giv5 by a cam]a rigidly fa/5$ to ! fuselage4 ,! second & ?ird %[ h& cam]a trails1 made by an inexp]i5c$ & by an exp]i5c$ obs]v]1 respectively4 ,!y %[ by comp>ison ) ! o!r figures t ! human body is an excell5t block to vibration1 b 9 unskill$ h&s a poor *eck to rapid erratic 7probably rotational7 motions ( ! cam]a4 ,! f\r? is ! trail giv5 by a cam]a support$ by gimbals b$d$ 9 sponge rubb] accurately 9 ! plane ( ! cam]a's c5t] ( gravity4 ,o!r trails are %[n 9 ! next *apt] 9 connection ) ! description ( practical cam]a m\nt+s4 ,cle>ly ! be/ susp5sion is t giv+ ! smalle/ amplitude ( displacem5t dur+ ! int]val ( "t cov]$ by an av]age exposure4 ,x is1 9 fact1 possible to det]m9e f ^! trails ! p]missible exposure = any assum$ p]missible blurr+ ( ! image4 ,! rigid m\nt+ trail indicates v bad conditions1 call+ = lit]ally in/antane\s exposures4 ,! c5t] ( gravity trail1 at ! o!r extreme1 %[s practically no limitation ( exposure 9 s f> z vibration is conc]n$1 ?us be>+ out ! !oretical conditions above discuss$4 ,an int]e/+ conclusion f ^! exp]im5ts is t a rapidly runn+ motor gives less h>mful vibration ?an a sl[ "o1 al?\gh 9 ! w> x 0 a common practice to ?rottle ! motor be=e expos+4 ,z might be expect$1 ! great] ! numb] ( cyl9d]s1 ! %ort] ! p]iod & ! small] ! amplitude ( ! vibration4 ,p5dul> ,cam]a ,supports4--,! design ( ! cam]a support may be approa*$ f a diff]5t /&po9t1 namely1 ) ! aim ( c>ry+ ! cam]a s t x w t5d to hang always v]tical4 ,9 mapp+ ?is is ( fundam5tal importance4 ,x is1 inde$1 a "q :e!r a]ial mapp+ w ev] be wor?y ( rank+ z a precision me?od unless ! cam]a c be m\nt$ s t its pictures are tak5 9 ! horizontal1 undi/ort$ position4 ,! simple/ way to hold ! cam]a v]tical is to m\nt x on gimbals1 ) its c5t] ( gravity bel[ ! po9t ( support4 ,:5 s m\nt$ ! cam]a sw+s z a p5dulum4 ,delicacy ( response to v>iation ( level is obta9$ by leav+ a consid]able di/ance betwe5 ! c5t] ( gravity & ! c5t] ( support4 ,oscillation ab\t ! v]tical position is to be prev5t$ by "s sy/em ( da% pots or o!r damp+4 ,a susp5sion ( ?is k9d is furni%$ ) ! ,brock film cam]a 7,fig4 #fj74 ,x w be se5 at once t ! relation ( c5t] ( gravity to c5t] ( support call$ = "h is 9 direct contradiction to ! requirem5ts = elim9at+ vibration4 ,ei!r "o requirem5t or ! o!r mu/ be sacrific$1 or else a compromise made 9 :i* nei!r delicate response to incl9ation ( ! plane nor fully satisfactory fre$om f vibration is atta9$4 ,?is is a v s]i\s objection to ! p5dul> support4 ,b ! really vital objection to ! p5dul> support is t x p]=ms its function only v p>tially4 ,x is entirely satisfactory only "u conditions ( /eady fly+1 z 9 a uni=m climb or glide1 ) ! plane tail or nose heavy1 or 9 fly+ ) "o w+ d[n4 ,z soon z we introduce any accel]ation1 z 9 mak+ a turn1 ! cam]a foll[s ! plane & n ! e>?4 ,x is true t mapp+ photography is done f a plane fly+ z level z possible1 & t except "u bad air conditions x holds its c\rse ) v little turn+1 if h&l$ by a skill$ pilot4 ,nev]!less1 a surpris+ly small deviation f /raight fly+ causes q s]i\s v>iations f ! v]tical4 ,x is ( int]e/ to calculate h[ l>ge may be ! horizontal accel]ations t accompany sw]v+s f a /raight c\rse :i* "o might ?9k insignificant4 ,= in/ance1 consid] ! horizontal accel]ation due to a turn hav+ a radius ( a kilomet] :5 ! plane is mov+ at #ajj kilomet]s p] h\r4 ,if a is ! accel]ation1 v ! velocity ( ! plane1 & r ! radius1 we h f elem5t>y dynamics t v#b a ---------- r ,sub/itut+ ! values *os51 we h-- #ajj1jjjb met]s a -------------------------- 4#gg ------------ #cfjjb #ajjj sec#b ,! accel]ation ( gravity be+ #i4hj met]s_/sec#b we h t ! ratio ( ! horizontal accel]ation to ! v]tical is 4#gg -------- 4#jgh #i4hj ,?is is ! tang5t ( ! angle ( deviation f ! v]tical1 f :i* ! angle turns out to be ab\t #d degrees1 a v consid]able error1 rapidly multipli$ z ! spe$ ( ! plane is increas$4 ,x is1 inde$1 op5 to "q :e!r ! av]age deviations f ! v]tical are n apt to be less ) ! cam]a rigidly fix$ to ! plane1 if guid$ by a skill$ pilot :o w hold ! %ip level at ! exp5se ( 8skidd+0 ! slight turns he mu/ make to hold 8 direction4 ,gyroscopic ,m\nt+s4--,! ideal support = ! a]ial cam]a w und\bt$ly be "o embody+ gyroscopic control ( ! cam]a's direction4 ,by prop] utilization ( ! pr9ciples ( ! gyroscope x is to be expect$ t n only c ! cam]a be ma9ta9$ v]tical1 b x may be support$ anti-vibrationally z well4 ,at ! pres5t "t ! problem ( gyroscopic control is 9 ! exp]im5tal /age1 s t only ! elem5ts ( ! problem & ! possible modes ( solution c be laid out4 ,! gyroscope consi/s ess5tially ( a heavy r+ or disc rotat+ at a high spe$ on an axis free to po9t 9 any direction 7,fig4 #gi74 ,if m\nt$ s t ! axes ( ! support+ gimbals pass ?r\gh ! c5t] ( gravity ( ! rotat+ disc1 ! result is a neutral gyroscope4 ,its *>act]i/ic is t its axis ma9ta9s its direction fix$1 b ?is fixity is ) respect to space & n ) respect to ! gravitational v]tical4 ,consequ5tly1 z ! e>? revolves ! incl9ation ( ! gyroscopic axis *anges ) respect to ! e>?4 ,9 latitude #de ?is *ange is approximately a degree 9 five m9utes4 ,fur!rmore1 ! action ( friction 9 ! supports1 :i* c nev] be entirely elim9at$1 also acts to sl[ly alt] ! direction ( ! gyroscopic axis4 ,!re=e1 unless "s erector is appli$ ev5 ! gyroscope w n p]=m ! task requir$ ( x4 ,illu/ration3 ,,fig4 #gi4--;,diagram ( simple gyroscope4 ,be=e discuss+ possible =ms ( erectors x may be not$ 9 g5]al1 fir/1 t ^! mu/ dep5d ^u gravity2 second1 t su* be+ ! case1 !y mu/ respond to ! resultant ( gravity & any accel]ation1 t is1 to ! app>5t or pseudo-gravity4 ,z already se51 ?is pseudo-gravity1 dur+ a turn1 is exactly :at limits ! usefulness ( ! p5dul> support1 & necessitates rec\rse to ! gyroscope4 ,! problem ?us becomes "o ( mak+ an erector-gyroscope comb9ation :i* w respond to true gravity & n to pseudo-gravity4 ,9 g5]al ?is problem w\ld be insoluble1 s9ce !re is no diff]5ce 9 ! nature ( ! accel]ation ( gravity & t due to c5trifugal =ce4 ,a way out is (f]$1 h[ev]1 by ! fact t true gravity acts cont9u\sly & at a small angle to ! axis ( ! gyro1 :ile ! compon5ts :i* cause ! pseudo-gravity are ( %ort duration1 liable to rapid *anges ( direction1 &1 on a turn1 act at a l>ge angle4 ,:at we require1 !re=e1 is an erector :i* w respond sl[ly b surely to ! av]age accel]ation1 :i* is d[nw>d1 b too sluggi%ly to be affect$ by ! %ort] p]iod accel]ations due to turns or rolls4 ,sl[ness ( response is a matt] ( ! erect+ =ces be+ small & ( ! mass & angul> velocity ( ! gyro disc be+ l>ge4 ,! success ( ! compromise call$ = dep5ds on ! relative times tak5 = ! gyroscope to tilt s]i\sly f ! true v]tical1 due to ! causes above m5tion$1 & = ! av]age turn or roll4 ,=tunately ! =m] is a matt] ( m9utes1 ! latt] ( seconds or at ! wor/ ( fractions ( a m9ute4 ,m ?an ?is1 s9ce ! roll or turn is apt to be ( mu* great] angle ?an any normal deviation ( ! gyroscopic axis f ! v]tical 9 ! same "t1 we are (f]$ ! possibility ( "s device = filt]+ out ! deviations :i* alone are to effect ! erector4 ,= in/ance1 by %unt+ ! re/or+ =ce :5ev] x is call$ ^u to act ?r\gh m ?an a pr$et]m9$ small angle4 ,z to ! me?od ( erect+ ! gyroscope1 its *>act]i/ic prop]ty mu/ be kept 9 m9d4 ,?is is t ! axis does n tilt "u an appli$ =ce 9 ! direction x w\ld if ! gyro 7 n rotat+1 b ar\nd an axis at "r angles to t ( ! appli$ c\ple4 ,?us 9 ,fig4 #gi1 if a weight is atta*$ z %[n1 ! disc does n incl9e d[nw>d t[>d ! weight1 ar\nd ! axis ,y1 ,y1 b precesses ab\t ! v]tical axis ,z1 ,z4 ,"s means is !re=e ne$$ to translate ! pull :i* any gravitational control1 su* z a freely sw++ p5dulum1 w\ld give1 into a pull ) at lea/ a compon5t at a f9ite angle to ?is4 ,9 ! ,gray /abiliz] sev]al metal balls are sl[ly rotat$ 9 a tray above ! c5t] ( gravity ( ! gyroscope4 ,specially %ap$ grooves or comp>tm5ts limit ! fre$om ( motion ( ^! balls s t :5 ! gyro is incl9$ ! balls travel at diff]5t di/ances f ! c5t] on ! asc5d+ & desc5d+ sides4 ,by ?is s*eme a c\ple is produc$ ab\t ! axis ?r\gh ! c5t] & ! l[ po9t ( ! disc1 :i* tilts ! app>atus to ! gravitational v]tical4 ,9 an alt]native =m ! balls are c>ri$ pa/ ! l[ po9t by _! mom5tum & are prev5t$ f return+ by ! walls ( ! conta9+ comp>tm5t1 :i* h mean:ile be5 advanc$ by ! rotation ( ! erector z a :ole4 ,! net result is to %ift ! c5t] ( gravity ( ! sy/em ( balls 9 ! prop] direction to erect ! gyro4 ,! rectify+ action is purposely made q sl[ s t ! displacem5ts ( ! balls due to pseudo-gravity w be av]ag$ out4 ,9 a design due to ,lucian1 small p5dulums "w ?r\gh electric contacts to actuate sol5oids :i* 9 turn move small weights 9 ! appropriate directions to give ! desir$ tilt4 ,response is made fairly quick & delicate1 & pseudo-gravity1 due to turns & rolls1 is r5d]$ inop]ative by ! contacts break+ :5ev] ! p5dulums sw+ m ?an ?ree or f\r degrees4 ,?is c only happ5 if !y move too quickly = ! erect+ =ces to act1 reliance be+ "h plac$ on ! *>act]i/ic diff]5ces ( action 9 respect to "t ( real & pseudo-gravitational =ces4 ,besides ! neutral gyroscope z j consid]$ !re is ! p5dul> or top type1 9 :i* ! c5t] ( gravity is n 9 ! plane ( ! supports4 ,9 g5]al ?is type dep5ds on a c\ple result+ f ! gravitational pull & ! inevitable friction ( ! supports to sl[ly tilt ! axis to ! gravitational v]tical4 ,?is type is sl[] to respond ?an ! designs 9 :i* a def9ite c\ple 9 ! prop] direction is provid$ & x rea*es ! true v]tical only ?r\gh a circuit\s pa?4 ,illu/ration3 ,,fig4 #hj4--;,diagram ( cam]a l9k$ to gyroscopic /abiliz]4 ,?ree me?ods ( controll+ a cam]a by a gyroscope are sugge/$4 ,"o is to fa/5 ! gyroscope rigidly to ! cam]a & m\nt ! :ole sy/em on gimbals4 ,a second is to m\nt bo? cam]a & gyro side by side on gimbals1 l9k+ ! two s t ! cam]a is mov$ p>allel to ! gyro 7,fig4 #hj74 ,a ?ird me?od is to utilize ! gyro to make electric contacts to op]ate motors :i* 9 turn move ! cam]a4 ,consid]able weight & space are requir$ = a gyroscope capable ( /abiliz+ a cam]a4 ,! rotat+ disc %\ld be ab\t half ! weight ( ! cam]a1 & ) its m\nt+ may be expect$ to d\ble ! room requir$ = ! cam]a alone4 ,motive p[] = ma9ta9+ ! gyro 9 cont9u\s rotation may be suppli$ by an air bla/1 or ! gyro may be made up z an induction motor--! latt] necessitat+ an alt]nat+ curr5t supply4 ,9 view ( ! space & weight limitations 9 a plane x is a "q /ill to be decid$ :e!r x is m economical to /abilize ! cam]a or to /abilize an incl9omet] & photograph its indications simultane\sly ) ! release ( ! %utt] :i* takes ! a]ial picture4 ,,*apt] ,,xv ,,practical ,,cam]a ,,m\nt+s ,g5]al ,consid]ations4--,cam]a m\nt+s z us$ dur+ ! w> 7 f> f be+ develop$ on ! basis ( sci5tific /udy or te/4 ,at fir/ ! ne$ = special support+ app>atus 0 n realiz$1 & ! susp5sions lat] 9 use 7 l>gely field-made affairs1 (t5 dep5d5t on adju/m5ts made accord+ to individual ta/e4 ,?r\gh lack ( accurate me?ods ( te/ & ( conclusive evid5ce on ! subject1 x 0 q common to f9d extremi/s :o1 on ! "o h&1 d5i$ ! efficacy ( susp5sions 9 g5]al1 & on ! o!r ard5tly support$ crazily conceiv$ support+ arrangem5ts :i* accurate comp>ative te/ %[ to be ev5 worse ?an useless4 ,9 ! ,fr5* s]vice1 despite num]\s types ( susp5sion available1 ! v g5]al practice 0 to lift ! cam]a f its support & hold x betwe5 ! knees4 ,or else ! h& 0 press$ on ! top ( ! cam]a dur+ exposure1 m reliance be+ plac$ on ! damp+ qualities ( ! body ?an on any ( ! rubb] or spr+ me*anisms4 ,z is cle>ly %[n by ! exp]im5tal data describ$ 9 ! la/ *apt]1 a correctly design$ support+ device1 c>ry+ ! cam]a accurately 9 ! plane ( its c5t] ( gravity1 accompli%es practically p]fect elim9ation ( vibrational tr\bles4 ,s important is ! use ( a m\nt & s important is x t ! m\nt %\ld be correctly dim5sion$ & adju/$ = ! cam]a1 t an entirely diff]5t attitude %\ld be adopt$ f ! preval5t "o :i* focuses att5tion on ! cam]a & reg>ds ! m\nt+ z a m]e auxili>y to be left m or less to *ance4 ,! m\nt+ %\ld be consid]$ an integral "p ( ! cam]a4 ,! man 9 ! field %\ld receive cam]a & m\nt toge!r1 leav+ z 8 only problem ! atta*m5t ( ! complete cam]a--&--m\nt unit to ! plane4 ,?is may be arrang$1 by prop] design+1 to be a simple matt] ( rigid bolt+ or /rapp+1 requir+ +5uity p]haps b n ! sci5tific k :i* is requir$ = m\nt+ design4 ,illu/ration3 ,,fig4 #ha4--8,l0 cam]a m\nt$ outside ! fuselage4 ,obs]v] us+ exposure plung]1 pilot us+ ,b[d5 wire release4 ,outbo>d ,m\nt+s4--,9 ! ,engli% s]vice ! cam]a 0 fir/ atta*$ to ! plane outside ! fuselage by a rigid frame1 to :i* ! cam]a 0 /rapp$ or bolt$ 7,fig4 #ha74 ,obvi\s objections exi/ to plac+ ! cam]a 9 ?is position1 su* z ! resi/ance ( ! w9d & ! difficulty ( *ang+ magaz9es4 ,h[ev]1 9 ! e>li] ,engli% planes ) _! fuselages ( small cross section no o!r accessible place = ! cam]a 0 to be f\nd4 ,vibrational di/urbances ) ! rigid outbo>d m\nt+ are q s]i\s1 z is s cle>ly indicat$ by ! trace %[n 9 ,fig4 #gh4 ,extremely %ort exposures are alone possible1 & a v l>ge proportion ( ! pictures are apt to be indi/9ct4 ,floor ,m\nt+s4--,a /ep 9 advance ( ! outbo>d m\nt+ is to support ! cam]a sn\t 9 a padd$ conical frame on ! floor ( ! plane 7,fig4 #hb74 ,?is m\nt+ avoids ! objection on ! gr\nd ( w9d resi/ance t holds ) ! outbo>d1 & has possibilities ( be+ work$ out z an entirely satisfactory support4 ,yet to be satisfactory1 ! po9t ( support mu/ lie 9 ! plane ( ! c5t] ( gravity ( ! cam]a1 & ! cam]a mu/ be ( a type t pres]ves its c5t] ( gravity un*ang$ 9 position z ! plates are expos$4 ,unless ^! conditions are fully met ! floor m\nt+ gives results little bett] ?an does ! outbo>d4 ,cradles or ,trays4--,floor space 9 ! cockpit be+ unavailable 9 ! battle-plane1 due to duplicate controls1 bomb sights1 etc41 ! ,engli% s]vice 0 driv5 to ! practice ( c>ry+ ! cam]a 9 ! comp>tm5t or bay beh9d ! obs]v]4 ,"h x 0 atta*$ ei!r to ! /ructural uprights or long]ons1 or to special uprights & cross-pieces built into ! plane to s]ve photographic ends4 ,z an int]m$i>y betwe5 ! cam]a & ! support+ cross-pieces !re 0 introduc$ ! cam]a tray or cradle4 ,?is is ess5tially a frame c>ry+ sponge rubb] pads into :i* ! cam]a is m or less deeply b$d$4 ,figs4 #hc & #hd %[ an ,am]ican ,l cam]a cradle bas$ on ! design ( ! ,engli% ,l cam]a tray4 ,?ick sponge rubb] pads support ! two ends ( ! cam]a top plate1 & additional pads are provid$ to hold ! nose ( ! cam]a4 ,c>eful te/s %[ ?is cradle to be sup]ior to ! outbo>d m\nt+1 b /ill leave mu* to be desir$4 ,its p]=mance is bett] ) ! nose ( ! cam]a left free4 ,illu/ration3 ,,fig4 #hb4--8,l0 cam]a 9 floor m\nt+4 ,illu/ration3 ,,fig4 #hc4--8,l0 cam]a & cradle m\nt 9 skeleton ,de,haviland #d fuselage1 side view4 ,t5nis-ball ,m\nt+4--,a v simple m\nt us$ by ! ,fr5* consi/s ( a frame enclos+ ! nose ( ! cam]a1 & c>ry+ f\r t5nis balls1 on :i* ! :ole weight re/s 7,fig4 #dj74 ,if ! c5t] ( support is 9 ! plane ( ! c5t] ( gravity & if ! f\r balls are ( uni=m age & ela/icity1 ?is =m ( support is good4 ,z provid$ by ! cam]a manufactur]1 ! t5nis ball frame fits mu* too f> d[n on ! cam]a4 ,ano!r application ( ! t5nis ball idea 0 frequ5tly made 9 ! ,fr5* s]vice1 9 :i* ! balls 7 close up "u ! %utt] h\s+ 7,fig4 #he74 ,additional support 01 h[ev]1 giv5 to ! cam]a nose by flexible rubb] b&s1 ! success ( ! :ole be+ l>gely a matt] ( ! adju/m5t ( ! t5sion on ! b&s4 ,illu/ration3 ,,fig4 #hd4--8,l0 cam]a & cradle m\nt 9 skeleton ,de,haviland #d fuselage1 front view4 ,p>allel ,motion ,devices4--,a =m ( susp5sion favor$ by ! ,fr5* consi/s ( p>allel bell cranks1 rigidly l9k$ toge!r & held up by spr+s4 ,m\nt+s ( ?is sort are illu/rat$ 9 ,figs4 #hf1 #hg1 #hh & #if4 ,! guid+ pr9ciple is t any sort ( %ock w be trans=m$ into a /raight up-&-d[n or side-wise motion ( ! cam]a1 :i* is h>mless4 ,! m\nt+ z adapt$ by ! ,engli% surr\nds ! cam]a body1 mak+ ! plane ( support some:]e ne> ! c5t] ( gravity4 ,9 c]ta9 ( ! ,fr5* susp5sions employ+ ?is pr9ciple ! :ole cam]a is hung bel[ ! bell cranks 7,fig4 #hf71 & !n ! nose is re/ra9$ by heavy rubb] b&s4 ,! net result is l>gely a matt] ( adju/m5t4 ,illu/ration3 ,,fig4 #he4--,t5nis ball susp5sion1 assi/$ by ela/ic b&s atta*$ to nose ( cam]a4 ,illu/ration3 ,,fig4 #hf4--;,fr5* spr+ & bell crank susp5sion4 ,illu/ration3 ,,fig4 #hg4--,u4 ,s4 h&-op]at$ #ah #bd c5timet] plate cam]a on bell crank m\nt ) rotat+ turret4 ,illu/ration3 ,,fig4 #hh4--,same cam]a 9 plate *ang+ position4 ,illu/ration3 ,,fig4 #hi4--,te/s ( cam]a m\nt+s3 7a7 de,ram cam]a on bell-crank-&-spr+ m\nt1 bel[ ! c5t] ( gravity2 7b7 same1 at c5t] ( gravity2 7c7 type 8,k0 film cam]a on univ]sal m\nt+ 7,fig4 #hh74 ,te/s on ! ,engli% design made 9 ! ,unit$ ,/ates ,air ,s]vice appe> to %[ t ! *ief virtue ( ! m\nt+ lies 9 ! approximation ( ! po9t ( support to ! c5t] ( gravity 9 ! ,engli% cam]as4 ,a de,ram cam]a support$ by its cone1 s t its c5t] ( gravity 0 consid]ably above ! c5t] ( support gave r poor results 7,fig4 #hi;a71 b :5 ! bell cranks 7 atta*$ ne> ! c5t] ( gravity1 highly successful results 7 obta9$ 7,fig4 #hi;b74 ,! ,fr5* de,ram cam]a z ord]$ = ! ,am]ican ,exp$ition>y ,=ce 0 fitt$ ) a bell crank support$ 9 ?is position4 ,figures #ij & #ia %[ a bell crank m\nt+ furni%$ ) a rotat+ turret4 ,?is 0 design$ to facilitate ! *ang+ ( magaz9es 9 ! ,engli% ,b ,m cam]a1 :i* is swung ar\nd ?r\gh #ij degrees f ! expos+ position to br+ ! magaz9e ne> ! obs]v]4 ,! cam]a %[n 9 ! m\nt+ is ! ,am]ican h&-op]at$ model 7type ,m71 9 :i* !re is ! same necessity = turn+ 9 ord] to manipulate ! bag magaz9e easily4 ,! cam]a is %[n 9 bo? expos+ & plate *ang+ positions4 ,an important detail ( ^! m\nts is a safety cat*1 :i* mu/ be fa/5$ be=e ! plane l&s1 9 ord] to prev5t ! %ocks ( l&+ f produc+ oscillations suffici5t to ?r[ ! cam]a out ( ! m\nt4 ,c5t] ( ,gravity ,rubb] ,pad ,supports4--,giv5 a cam]a ^: c5t] ( gravity does n *ange dur+ op]ation1 a simple & entirely adequate anti-vibration support is furni%$ by a r+ ( sponge rubb] 9 ! plane ( ! c5t] ( gravity4 ,b if provision has to be made = oblique views or = adju/+ ! cam]a to ! v]tical1 some?+ m elaborate is necess>y4 ,illu/ration3 ,,fig4 #ij4--,u4 ,s4 model de,ram cam]a on anti-vibration m\nt+ adju/able = ! angle ( incid5ce ( ! plane4 ,illu/ration3 ,,fig4 #ia4--,u4 ,s4 de,ram cam]a & m\nt in/all$ 9 photographic ,de,haviland #d 7,fig4 #ajj74 ,view$ f above ! obs]v]'s cockpit4 ,illu/ration3 ,,fig4 #ib4--,u4 ,s4 type 8,k0 film cam]a on univ]sal m\nt+1 v]tical position4 ,illu/ration3 ,,fig4 #ic4--,u4 ,s4 type 8,k0 film cam]a on univ]sal m\nt+1 oblique position4 ,m\nt+s = ! ,am]ican de,ram & = ! ,air ,s]vice film cam]a1 embody+ ! results ( complete /udy ( ! anti-vibration problem1 are %[n 9 ,figs4 #ij1 #ib & #ic4 ,trusses c>ry+ ! cam]as on pivots re/ on f\r pads ( sponge rubb] :i* are m\nt$ on frames correctly spac$ ready = atta*m5t to ! cross-pieces ( ! airplane cam]a supports4 ,9 ! de,ram 7,fig4 #ij7 ! pivots1 atta*$ to ! cam]a body1 p]mit x to be level$ =e & aft1 to comp5sate = ! incl9$ position ( ! fuselage assum$ at high altitudes or 9 "s conditions ( load+4 ,?is w sometimes am\nt to z mu* z #aa or #ab degrees1 :i* is v s]i\s1 s9ce "o degree causes 7) an angul> field ( #bj degrees7 ab\t "o p] c5t4 diff]5ce ( scale at ! two sides ( ! plate4 ,! film cam]a m\nt+ c>ries ! cam]a 9 a conical r+1 & is pivot$ n only = v]tical adju/m5t1 b = ! tak+ ( obliques z well 7,fig4 #ic74 ,^! m\nts transmit practically no vibration4 ,illu/ration3 ,,fig4 #id4--,te/s on two types ( cam]a m\nt3 7a7 ,support at bottom ( cam]a2 7b7 support above c5t] ( gravity4 ,a caution mu/ be not$ ) reg>d to c5t] ( gravity m\nt+s4 ,any *ange 9 ! cam]a1 9 p>ticul> ! sub/itution ( a %ort = a long l5s cone1 mu/ be made s z to cause no alt]ation ( ! relative positions ( ! c5t] ( support & ! c5t] ( gravity4 ,ei!r ! %ort cone mu/ be weight$1 or additional support+ pivots mu/ be provid$ 9 ! plane ( ! new c5t] ( gravity4 ,! ,italian & ,g4 ,e4 ,m4 ,m\nt+s4--,^! m\nts 7,figs4 #di & #ei7 are simil> 9 t ! protection f vibration is furni%$ by an ela/ic support at ! bottom ( ! cam]a4 ,te/s %[ t ^! two cam]as give v simil> results1 ( ! unsatisfactory sort to be expect$ f ?is k9d ( m\nt+ 9 view ( ! lessons ( ! la/ *apt] on ! prop] po9t ( support4 ,fig4 #id1 a1 %[s a trace giv5 by ! ,italian m\nt4 ,! p]missible exposure1 on ! crit]ion adopt$1 is v %ort ) ei!r m\nt1 ab\t #a_/bjj second4 ,! ,brock ,susp5sion4--,?is consi/s ( a pair ( frames into :i* ! cam]a is fitt$ by ball be>+ pivots1 s t x is free to move 9 any direction 7,fig4 #fj74 ,9 ord] to p]mit gravity to control ! direction ( ! cam]a1 ! po9t ( support is made consid]ably 7t5 in*es7 above ! c5t] ( gravity4 ,air da% pots are provid$ = damp+ ! sw+s4 ,z already expla9$1 ! p5dul> me?od ( support is 9 basic contradiction to ! requirem5ts = vibration elim9ation4 ,te/s ( ! ,brock susp5sion1 %[n 9 ,fig4 #id1 b1 indicate x to be ( l[ effici5cy 9 damp+ out ! %ort p]iod vibrations :i* are responsible = poor def9ition4 ,,*apt] ,,xvi ,,! ,,in/allation ,,( ,,cam]as ,,& ,,m\nt+s ,,9 ,,planes ,conditions to ,be ,met4--,! *>act]i/ic difficulty 9 in/all+ ! airplane cam]a is t !re is no place = x4 ,aft] ! gasol9e supply1 ! armam5t1 ! wireless1 ! oxyg5 tank1 ! bombs1 & o!r necessities are tak5 c>e ( !re is nei!r space available nor weight all[able4 ,:]e space may be f\nd x w be inaccessible1 or accessible only ?r\gh a maze ( t5sion & control wires2 or x w be 9 a position :]e any weight w endang] ! balance ( ! plane4 ,plane design has 9 fact be5 m or less ( a conflict betwe5 ! a]onautical eng9e]1 :o is design+ ! airplane prim>ily z a ma*9e to fly1 & ! armam5t & in/rum5t m51 :o look ^u x z a plat=m = _! app>atus4 ,lack ( appreciation ( ! extreme importance ( a]ial photography result$1 dur+ a l>ge "p ( ! w>1 9 ! cam]a in/allation be+ neglect$ until ! plane 0 suppos$ly entirely design$1 & ev5 9 production4 ,at t /age ! in/allation c\ld be b a make%ift4 ,only 9 ! lat] /ages ( ! w>1 :5 plane design became a matt] ( cop]ation betwe5 all conc]n$1 7 fairly conv5i5t & satisfactory arrangem5ts made = ! cam]a4 ,always1 h[ev]1 ! rapid succession ( new plane designs1 ) v>i\s %apes ( fuselage & details ( /ructure1 made cam]a in/allation 9 ! w> plane a matt] call+ = ! greate/ +5uity4 ,! problem 0 met 9 "p by con/ruct+ bo? cam]as & m\nt+s 9 sections1 to be labori\sly worm$ 9 ?r\gh inadequate ap]tures1 9 "p by lat] /ructural *anges 9 ! planes1 su* z ! sub/itution ( v5e] r+s or frames = ! t5sion wires4 ,9 c]ta9 cases ! re> cockpit controls 7 omitt$1 !reby free+ accessible & (t5 adequate space = ! l>g] cam]as4 ,re> controls 7 nev] us$ 9 ! ,g]man planes1 s t _! /&>d practice 0 to c>ry ! cam]a =w>d ( ! obs]v]4 ,?is1 toge!r ) ! g5]al re/riction to ! #ac #ah c5timet] size plate1 made ! in/allation problem less difficult 9 ! ,g]man aircraft ?an 9 ! ,alli$4 ,practical ,solutions4--,an important feature ( cam]a in/allation has already be5 m5tion$1 b may well be repeat$ = emphasis4 ,! cam]a & its anti-vibration m\nt+ %\ld always be consid]$ z a unit1 & %\ld be s design$ t simple bolts or /raps w suffice to fa/5 x 9 its place 9 ! plane4 ,ev5 %\ld ! spac+ ( ! /ructural p>ts ( ! plane n correspond to t anticipat$ by ! m\nt+ design1 ! +5uity ( ! man 9 ! field may be dep5d$ ^u to make ! necess>y alt]ations or additions to ! plane4 ,! design ( ! cam]a susp5sion itself _c1 h[ev]1 be left to un$ucat$ +5uity4 ,assum+ ! cam]a & m\nt+ suppli$1 ! next /ep--a v difficult "o--is to insure uni=mity 9 ! /ructures to be built into ! planes = ! purpose ( support+ ! cam]a m\nt+s4 ,) ?is uni=mity mu/1 h[ev]1 be comb9$ ! greate/ possible flexibility to provide = v>i\s designs ( cam]as4 ,9 ! ,engli% s]vice ! /&>d cam]a in/allation consi/s ( wood5 uprights ) cross b>s a?w>t ! plane1 adju/able z to height 7,fig4 #ie74 ,a di/ance betwe5 ! cross b>s ( #ac in*es has be5 /&>diz$1 & all cam]a cradles & m\nt+s are not*$ or o!rwise spac$ to fit ?is dim5sion4 ,! in/allation adopt$ 9 ! ,am]ican planes is simil>1 b ) a di/ance ( #af in*es betwe5 cross b>s4 ,^! uprights & cross b>s are ord9>ily situat$ 9 ! bay beh9d ! obs]v]1 b c be plac$ 9 any available space4 ,fig4 #hc %[s1 9 a model bay1 ! arrangem5t ( uprights & cross b>s 9 ! ,am]ican ,,dh #d1 ) ! ,l cam]a 9 place 9 its cradle4 ,x is j possible to introduce cam]a & cradle sep>ately f ! obs]v]'s cockpit ?r\gh ! t5sion wires1 &1 by uncom=table rea*+1 magaz9es may be *ang$4 ,illu/ration3 ,,fig4 #ie4--8,,lb0 cam]a ) #bj-;in* l5s1 m\nt$ on bell-crank susp5sion 9 skeleton fuselage4 ,/ream-l9$ hood bel[ to cov] project+ end ( l5s cyl9d]4 ,propell] & ,b[d5 release 9 place4 ,a /ep 9 advance is made :5 ! top t5sion wires & sup]/ructure are replac$ by a rigid frame ) an op5+ l>ge en\gh to admit ! entire cam]a & m\nt+4 ,:5 ?is is done consid]ably l>g] cam]as may be accommodat$ 9 ! same siz$ bay1 z %[n 9 ,fig4 #if4 ,a fur!r advance1 f ! /&po9t ( accessibility & conv5i5ce ( in/allation1 foll[s :5 ! t5sion wires betwe5 obs]v]'s & cam]a bay are replac$ by a ply-wood r+1 z %[n 9 ,fig4 #ig4 ,"h ! only s]i\s limitations are ^? due to ! v]tical height ( ! cam]a1 & ( c\rse its weight4 ,op5+s = ! l5s to po9t ?r\gh are simply provid$ 9 ! fabric cov]$ aircraft1 by cutt+ ?r\gh ! canvas & /iff5+ ! edge ( ! hole by wire4 ,t5sion wires are (t5 9 ! way4 ,!y may ei!r be disreg>d$1 s9ce !y m]ely cut (f a little light1 or replac$ 9 "p by metal r+s1 z %[n 9 ,fig4 #if4 ,9 v5e] cov]$ fuselages ! hole mu/ ( c\rse g ?r\gh ! wood4 ,?is may be undesirable1 s9ce ! v5e] is dep5d$ on to furni% /ructural /r5g?1 a po9t :i* fur!r emphasizes ! importance ( ! photographic requirem5ts be+ ?or\ghly consid]$ :ile ! plane is be+ design$4 ,s+le seat] or sc\t planes d n l5d !mselves to ! ins]tion ( su* /&>diz$ uprights & cross-pieces1 because ( _! small size & ! common utilization ( all space inside ! fuselage = gasol9e tanks & control wires4 ,"s ,fr5* sc\ts1 ^: fuselages are v wide1 due to ! rot>y eng9es1 h be5 fitt$ ) comp>tm5ts = contemplat$ automatic film cam]as4 ,! mo/ commonly us$ cam]a 9 ! s+le seat] 01 h[ev]1 ! ,italian #bd-plate s+le-motion app>atus 7,fig4 #di74 ,?is cam]a & its c>ry+ tray occupy v little lat]al space & h 9 actual practice be5 c>ri$ b5ea? ! seat or pu%$ up ?r\gh an op5+ 9 ! bottom ( ! fuselage "u ! gasol9e tank4 ,:atev] criticism may be made ( ! adequacy ( ! m\nt+1 x mu/ be said t ! cam]a1 z us$1 is p]haps ! mo/ em95tly practical ( all develop$ 9 ! w>1 z its use on sc\ts te/ifies4 ,illu/ration3 ,,fig4 #if4--,u4 ,s4 type 8,k0 film cam]a on bell-crank m\nt1 9 cam]a bay ( ,de,haviland #d4 ,v5e] frame at top ( bay 9 place ( usual cross-wires4 ,illu/ration3 ,,fig4 #ig4--,section ( fuselage ( v5e] con/ruction af=d+ sup]ior accessibility to cam]a4 ,special ,photographic ,planes4--,z cam]as grew 9 size1 ! difficulty ( in/all+ !m 9 planes built )\t reg>d to photographic requirem5ts greatly increas$4 ,few planes c\ld c>ry ev5 ! #ej c5timet] focus cam]a obliquely )\t ! necessity ( pok+ its nose ?r\gh ! side :]e x w\ld cat* w9d & oil2 :ile ! #abj c5timet] cam]a c\ld be c>ri$ obliquely only 9 ! =e & aft position4 ,ev5 v]tical in/allation ( ! latt] cam]a 0 really feasible 9 b few planes2 sometimes ! cam]a 0 c>ri$ to ! exclusion ( ! obs]v]--&1 9 fact1 ?is size 0 nev] us$ by ! ,engli%1 ^: fuselages 7 small 9 cross-section4 ,?is situation l$1 late 9 ! w>1 to /eps t[>d produc+ planes design$ prim>ily = photographic reconnaissance4 ,9 ^! ! cam]a w\ld be entirely accessible1 & cam]as ( any size c\ld be c>ri$ 9 any desir$ position4 ,"o s*eme :i* prop]ly belongs "u ?is head+ 0 ! provision ( a special removable photographic cockpit1 = ! front or nose ( a tw9-motor$ ?ree seat]4 ,o!r noses1 = bomb+ & heavy ma*9e guns1 7 also plann$1 all to be int]*angeable4 ,s9ce ! regul> photographic bay ) uprights & cross-pieces 0 also provid$ to ! re>1 ?is special photographic %ip c\ld on occasion d two classes ( "w1 su* z long focus spott+ & %ort focus mapp+4 ,! mo/ completely work$ out photographic plane 0 probably ! model designat$ ,p#a by ! ,unit$ ,/ates ,air ,s]vice4 ,?is is a modifi$ ,de,haviland #d 9 :i* ! re> controls h be5 remov$ & ! c[l+ rais$ & at ! same "t made squ>] 9 cross-section4 ,! space =m]ly occupi$ by ! re> controls provides ample room = all types ( cam]a4 ,^! are c>ri$ on uprights at ! /&>d di/ance ap>t1 #af in*es1 ) cross-pieces adju/able z to height4 ,! cam]a space is accessible n only f ! obs]v]'s cockpit1 b f above1 ^u fold+ back ! metal cov]4 ,doors at ! bottom & at ea* side p]mit n only v]tical b oblique exposures4 ,! latt] are n int]f]$ ) by ! w+s1 z !y w\ld be 9 "s designs ( plane if ! cam]a occupi$ ! same position relative to ! cockpits4 ,fig4 #ia %[s ! de,ram cam]a 9 place1 z se5 f ! re>4 ,figs4 #ih & #ii %[ ! #ah #bd c5timet] film cam]a1 set bo? = v]tical & oblique views4 ,negative l5ses are provid$ = bo? pilot & obs]v]1 ! "o = ! pilot p]mitt+ him to see f a po9t f> ahead to directly und]nea?1 :ile ! obs]v]'s is furni%$ ) cross wires bel[ & et*$ rectangles ( ! cam]a field sizes on ! upp] surface4 ,w9d[s ( non-breakable glass assi/ 9 sight+ obliques4 ,! accompany+ picture 7,fig4 #ajj7 ( ! plane %[+ an oblique cam]a 9 position gives an excell5t idea ( its appe>ance4 ,its special features are wor?y ( copy+ 9 peace-"t photographic aircraft4 ,in/allation ( ,auxili>ies4--,x is q necess>y t ! cam]a l5s be protect$ f spla%+ mud & (t5 f oil spray due to ! motor4 ,= ?is purpose an easily op5$ & clos$ door is ess5tial1 unless ! cam]a is c>ri$ well up 9 ! plane4 ,an alt]native1 possess+ c]ta9 advantages1 is to incorporate into ! cam]a protect+ flaps op]at+ 9 front ( ! l5s1 :i* op5 only :5 ! exposure is made4 ,if ! cam]a projects beyond ! fuselage1 /ream l9$ hoods 7,fig4 #ie7 mu/ be provid$ to protect ! cam]a nose ) ! m9imum ( air resi/ance4 ,illu/ration3 ,,fig4 #ih4--bj-;in* focus automatic film cam]a m\nt$ obliquely 9 photographic ,,dh-#d4 ,illu/ration3 ,,fig4 #ii4--bj-;in* focus automatic film cam]a m\nt$ v]tically 9 photographic ,,dh-#d4 ,illu/ration3 ,,fig4 #ajj4--;,de,haviland #d re-con/ruct$ z a special photographic plane1 %[+ #bj-;in* cam]a m\nt$ = oblique photography4 ,! m\nt+ ( ! regul> cam]a auxili>ies--releases1 sights1 propell]s1 spe$ controls1 motors--is usually a great bo!r1 due to lack ( space & to ! sev]e re/rictions on me?ods ( fa/5+4 ,screws 9 long]ons or uprights are taboo4 ,metal /raps to g ar\nd /ructural p>ts are ! approv$ device1 b ) v>iations 9 ! size ( ^! memb]s1 ! holes1 /raps1 bolts & nuts provid$ are v apt n to fit4 ,*anges ( con/ruction1 su* z t f skeletons cov]$ ) fabric to v5e] bodies1 also int]f]e ) any /&>d means ( atta*m5t1 & leave ?is1 l _m o!r problems 9 w>-"t a]ial photography1 to ! res\rcefulness ( ! man 9 ! field4 ,magaz9e racks mu/ be tuck$ away 9 any available space4 ,"u ! seat is a position frequ5tly utiliz$4 ,especially ) plates is x desirable to c>ry ! extra magaz9es 9 a position to int]f]e z little z possible ) ! balance ( ! plane4 ,9 ! ,,dh #d ?is means t !y %\ld be c>ri$ if possible =w>d ( ! obs]v]1 ev5 ?\gh he mu/ turn completely ar\nd to get & ins]t ea* magaz9e4 ,,iv ,,s5sitiz$ ,,mat]ials ,,& ,,*emicals ,,*apt] ,,xvii ,,! ,,di/ribution ,,( ,,light1 ,,%ade ,,& ,,color ,,9 ,,! ,,a]ial ,,view ,! g5]al appe>ance ( ! e>? z view$ f above has already be5 describ$ & illu/rat$ 7,figs4 #aj & #aa74 ,x rema9s to deal ) ! e>?'s appe>ance 9 a m analytic & quantitative mann]1 9 ord] to decide ^u ! *>act]i/ics to be s\ght 9 our photographic s5sitive mat]ials4 ,range ( ,brightness4--,! abs5ce ( great contra/s s app>5t 9 ! view ( ! e>? f a plane is confirm$ by photometric obs]vations4 ,^! %[ t ! av]age l&scape1 z se5 f ! air1 r>ely pres5ts a range ( brightness ( m ?an sev5 to "o1 ev5 :5 se5 )\t ! pres5ce ( veil+ haze4 ,x is to be rememb]$ t %ad[s con/itute no important "p ( ! a]ial l&scape4 ,v]tical walls 9 %ad[1 :i* =m a sub/antial "p ( ! surfaces se5 by an obs]v] on ! gr\nd1 are invisible or greatly =e%ort5$ f ! air4 ,moreov]1 !y are nev] contra/$ aga9/ ! sky1 :i* is photographically (t5 ! brighte/ "p ( ! ord9>y picture4 ,to ! aviator's eye %ad[s on ! gr\nd are only ( any l5g? at e>ly & late daylight h\rs4 ,ev5 at ^! times !y cov] b a small area1 s9ce ! numb] ( high v]tically project+ objects 9 a repres5tative l&scape is small4 ,lack+ %ad[s1 ! brightness range is only t betwe5 v>i\s k9ds ( e>?1 wat]1 & vegetation4 ,*alk 7f fre%ly dug tr5*es71 reflect$ sunlight f wat]1 or m>ble build+s1 furni% almo/ ! only ext5sions to ! brightness scale z above giv54 ,diurnal & seasonal *anges4 ,dur+ ! w9t] mon?s on ! ,we/]n ,front photography f ! air 0 only possible = two or ?ree h\rs ar\nd noon1 on cle> days4 ,?is calls att5tion to ano!r factor ( prime importance1 namely1 ! l>ge v>iation 9 ! int5sity ( daylight dur+ ! c\rse ( ! day & dur+ ! c\rse ( ! ye>4 ,illu/ration3 ,,fig4 #aja4--,v>iation ( av]age daylight int5sity dur+ ! day4 ,measurem5ts %[+ typical v>iations f morn+ to night are exhibit$ 9 ,fig4 #aja1 f :i* x appe>s t !re is an increase 9 illum9ation ( f\r to five times f #h o'clock--:5 x w\ld be consid]$ full daylight = purely visual obs]vation--until noon1 :ile !re is a correspond+ decrease by f\r o'clock4 ,fig4 #ajb %[s sets ( measurem5ts by two diff]5t au?orities :i* give ! av]age int5sity ( daylight = ea* mon? ?r\gh\t ! ye>4 ,f ,decemb] to ,july !re is an increase ( approximately t5 times4 ,f bo? sets ( data x !re=e appe>s t--neglect+ ! frequ5t occurr5ce ( cl\ds :i* r$uce ! illum9ation to a half or a qu>t] or ev5 less--a v>iation 9 illum9ation ( =ty or fifty times occurs betwe5 mid-day 9 summ] & morn+ 9 w9t]4 ,9 ! photography ( /ation>y objects on ! gr\nd ?is range ( int5sities is easily tak5 c>e ( by selection ( l5s /op & %utt] spe$4 ,on ! airplane x is q o!rwise1 because ! %utt] spe$s call$ = at ! l[] illum9ations are mu* sl[] ?an ! motion ( ! plane w all[4 ,illu/ration3 ,,fig4 #ajb4--,v>iation ( int5sity ( daylight ?r\gh ! ye>2 two diff]5t sets ( measurem5ts4 ,haze4--,at l[ altitudes ! brightness range is sub/antially t :i* w\ld be obta9$ by photometric measurem5ts ( soil & vegetation made at ! e>?'s surface4 ,at high] altitudes1 especially above #bjjj met]s1 ?is brightness range is mat]ially decreas$ by atmosph]ic haze4 ,! significance ( ?is lies 9 ! fact t = safety f anti-aircraft guns1 w>-"t a]ial photography mu/ be c>ri$ out at v great elevations4 ,t[>d ! end ( ! ,great ,w> photographic missions travel+ at f #ejjj to #gjjj met]s 7 ! rule4 ,at ^! heights1 ev5 9 v cle> wea!r1 a veil ( blui%-:ite haze r$uces ! already small contra/s /ill m4 ,"s means = ov]com+ ! effect ( ?is haze becomes imp]ative1 !re=e1 9 ord] to secure 9 ! picture ev5 ! normal contra/ ( ! object4 ,haze is to be %>ply di/+ui%$ f cl\ds or fog4 ,cl\ds & fog consi/ ( globules ( wat] vapor ( l>ge size1 opaque to light4 ,haze1 on ! contr>y1 is m opaque to "s colors ?an to o!rs1 or is selective 9 its veil+ effect4 ,its scatt]+ action on light is greate/ 9 ! violet & blue ( ! spectrum1 decreas+ rapidly ?r\gh ! gre51 yell[1 & r$1 ! exact relation be+ t ! scatt]+ is inv]sely z ! f\r? p[] ( ! wave-l5g?4 ,x is1 consequ5tly1 possible to pi]ce or cut haze by us+ yell[1 orange1 or r$ color scre5s4 ,x is ?is possibility :i* has l$ to ! ext5sive use ( yell[ or orange goggles = %oot+ & = naval look\t "w4 ,9 a]ial photography ! equival5t is to be f\nd 9 color filt]s1 us$ ) color s5sitive 7or?o*romatic or pan*romatic7 plates1 :i* h be5 f\nd ess5tial = all high altitude "w4 ,color4--,visual obs]vation f ! airplane is aid$ 9 no inconsid]able degree by ! diff]5ces ( color t exi/ betwe5 v>i\s objects ( ne>ly ! same brightness4 ,?is means ( di/+ui%+ diff]5ces ( "* fails 9 ! photographic plate1 :i* is color-bl9d2 t is1 x reproduces all objects z grays ( v>y+ brightness4 ,x is color-bl9d 9 ano!r s5se z well1 9 t x evaluates colors z to brightness diff]5tly f ! way ! eye does1 ov]rat+ blues & violets & und]rat+ yell[s & r$s4 ,?is fir/ k9d ( color-bl9dness is a positive disadvantage1 = x leaves available = diff]5tiat+ objects only _! brightness diff]5ces4 ,! second k9d ( color-bl9dness may on occasion actually be an advantage4 ,= x may happ5 by accid5t1 or by design 7?r\gh ! skilful use ( color filt]s71 t objects appe>+ ne>ly ! same to ! eye appe> diff]5t 9 ! plate4 ,m w be said ab\t ?is 9 connection ) ! use ( filt]s = ! detection ( cam\flage4 ,! range ( hues se5 9 ! a]ial l&scape is n l>ge4 ,gre5s 7grass & foliage7 pr$om9ate1 foll[$ by br[ns 7e>?71 nei!r color be+ bright or saturat$4 ,ov] t[ns or cities we f9d t grays 7roads7 & r$d] br[ns 7brick7 are conspicu\s4 ,blues are practically nev] se51 al?\gh x is to be not$ t a fair %>e ( ! illum9ation ( ! gr\nd is by blue sky light & t ! haze itself is blui%4 ,consequ5tly1 ! g5]al tone ( a l&scape is mu* blu] ?an "o w\ld be apt to imag9e x f consid]ation ( ! g5]al gre5 & br[n "* ( ! con/itu5t objects4 ,a color photograph f ! air w\ld greatly resemble a pa/el 9 its l[ range ( tones & ! abs5ce ( bright colors4 ,! ,photographic ,requirem5ts ,dictat$ by ,brightness & ,color ,consid]ations4--,consid]+ only ! dem&s made by ! "* ( ! view pres5t$ to ! airplane cam]a1 & leav+ out ( acc\nt o!r limitations to photographic op]ations 9 ! plane1 c]ta9 requirem5ts z to s5sitiz$ mat]ials may be outl9$4 ,fir/ ( all1 ! photographic process mu/ n r$uce1 b %\ld r be capable ( exagg]at+1 ! range ( brightness ( ! object4 ,pref]ably ! sev5-to-"o range ( ! object photograph$ %\ld be l5g!n$ out to ! full range ( ! pr9t+ pap]1 :i* may be two to ?ree times ?is4 ,) su* an increase ( range1 ^? m9ute diff]5ces ( brightness are acc5tuat$1 on :i* ! detection ( _m objects dep5ds4 ,next1 ! plate or film mu/ be s5sitive to ! portion ( ! spectrum transmitt$ by a yell[ or orange filt] :i* w cut out ! effect ( haze4 ,?is calls = or?o*romatic or pan*romatic plates1 dep5d+ on ! dep? ( filt] requir$4 ,next1 if ! objects to be photograph$ diff] little 9 brightness b are diff]5t 9 color composition1 we may h to rely on color filt]s ( peculi> transmissions1 capable ( translat+ ^! color diff]5ces into brightness diff]5ces4 ,^! w1 9 g5]al1 call = fully color s5sitive1 or pan*romatic plates4 ,9 conclusion x may be po9t$ out t ! endeavor 9 ord9>y or?o*romatic photography--to reproduce ! visual brightness ( colors 9 ! photographic pr9t--has no real ju/ification 9 a]ial "w4 ,nei!r 9 respect to color values nor 9 respect to brightness range is x ! object ( a]ial photography1 especially = w> purposes1 to pres5t a tru?ful tone reproduction4 ,its aim is r ! adequate diff]5tiation ( detail1 by :atev] means necess>y4 ,,*apt] ,,xviii ,,*>act]i/ics ,,( ,,photographic ,,emulsions ,! purely photographic problem 9 a]ial photography1 z di/9ct f ! in/rum5tal "o1 is ! selection ( photo s5sitive mat]ials :i* w yield useful results "u ! conditions peculi> to exposure f ! air4 ,aft] su* mat]ials h be5 f\nd by ext5sive field te/s1 x is preem95tly desirable to det]m9e _! *>act]i/ics 9 su* t]ms t ! k9d ( plate or film may !reaft] be specifi$ & select$ on ! basis ( purely laboratory te/s4 ,specification mu/ be made 9 t]ms ( ! ord9>y s5sitometric con/ants ( ! photographic emulsion--its spe$1 contra/1 fog1 developm5t factor1 its color s5sitiv5ess1 its ability to r5d] f9e detail1 & its gross] physical prop]ties su* z h>dness & %r9kage4 ,s5sitometry4--,! mo/ g5]ally us$ sy/em ( s5sitometry is t ( ,hurt] & ,driffield1 commonly ref]r$ to z ! 8,h ,d40 ,by ?is sy/em1 9 ord] to det]m9e ! *>act]i/ics ( a giv5 photographic plate1 x is necess>y to take a s]ies ( graduat$ exposures1 a /&>d illum9ation ( ! plate be+ v>i$ 9 kn[n am\nt by a rapidly rotat+ disc cut to a s]ies ( diff]5t op5+s1 or by "s o!r suitable means4 ,! negative ?us obta9$ is develop$ 9 a /&>d develop] = a def9ite "t1 at a fix$ temp]ature1 & is !n measur$ = transmission on a photomet]4 ,! foll[+ t]ms are def9$ & us$ 9 plott+ ! results3 int5sity ( light transmitt$ ,i ,transp>5cy ,t ---------------------------------------- -------------------- -------------- int5sity ( incid5t light ,i,o int5sity ( incid5t light ,i,o #a ,opacity ,o ---------------------------------------- -------------------- -------------- ------ int5sity ( transmitt$ light ,i ,t ,d5sity ,d -log#aj,t log#aj,o ,hurt] & ,driffield po9t$ out t a negative w\ld give a true repres5tation ( ! diff]5ces 9 ! light & %ade ( ! object if x reproduc$ ^! diff]5ces by equival5t diff]5ces 9 opacity4 ,?is is equival5t to /at+ t if ! d5sities are plott$ aga9/ ! log>i?ms ( ! correspond+ exposures1 a /raight l9e %\ld be obta9$ at #de degrees to ! axis ( exposure times4 ,if ! l9e is at ano!r angle ! opacities ( ! negative w be proportional to ! brightness ( ! object photograph$1 b ! contra/ w be diff]5t4 ,a typical ,h ,d plot is %[n 9 ,fig4 #ajc4 ,x w be not$ t two curves are %[n4 ,^! are obta9$ ) diff]5t developm5ts1 & illu/rate ! fact t ! contra/ or proportionality betwe5 exposure diff]5ces & opacity diff]5ces is a matt] ( "t ( developm5t4 ,ea* ( ^! curves exhibits c]ta9 *>act]i/ics :i* are common to all made 9 ?is way4 ,!re is prim>ily a /raight l9e portion1 :]e opacities are proportional to illum9ation4 ,?is is commonly call$ ! region ( correct exposure4 ,! slope ( ?is /raight l9e portion--! ratio ( d5sity_/7log exposure7--is ! developm5t factor1 commonly d5ot$ by 810 a gamma ( unity d5ot+ exact tone r5d]+4 ,bel[ ! region ( correct exposure is a 8toe10 or region ( small] contra/1 call$ ! region ( "u exposure4 ,above ! correct exposure region is ano!r :]e ! opacity approa*es con/ancy 7aft]w>ds decreas+ or 8rev]s+071 call$ ! region ( ov] exposure4 ,! spe$ ( a plate on ! ,h ,d scale is giv5 by ! int]section ( ! /raight l9e portion ( ! *>act]i/ic curve :5 produc$1 ) ! exposure axis4 ,?is int]section po9t1 call$ ! in]tia1 is ! same irrespective ( ! "t ( developm5t1 z is %[n 9 ,fig4 #ajc4 ,! num]ical value ( ! spe$ is obta9$ by divid+ #cd by ! in]tia1 :5 ! exposure is plott$ 9 c&le-met]-seconds4 ,if a plate is develop$ until no m d5sity & contra/ c be obta9$1 its developm5t factor is !n 1 7gamma inf9ity71 & ! l>g] ?is is ! m a plate c be =c$ 9 developm5t4 ,if ! plate fogs 9 its unexpos$ portions ?is fog is measur$ & record$ 9 d5sity units along ) ! o!r con/ants4 ,! spe$ ( developm5t is repres5t$ by ! velocity con/ant1 commonly symboliz$ by 4 ,illu/ration3 ,,fig4 #ajc4--,typical *>act]i/ic curves ( photographic plate4 ,! l5g? ( ! /raight l9e portion det]m9es ! latitude ( ! plate1 or ! range ( p]missible exposures to secure a 8p]fect negative40 ,?us if we assume t an object has a range ( brightness ( #a to #cj1 !n a plate ) a /raight l9e *>act]i/ic ext5d+ ov] a range ( #a to #abj w\ld h a latitude ( #abj_/cj or #d4 ,t is1 ! exposure c\ld be z mu* z f\r times ! necess>y "o1 & /ill give ! same result on a suffici5tly expos$ pr9t4 ,if ! latitude ( ! plate is too small1 ! %ad[s w fall 9 ! "u exposure region1 ! high-lights 9 ! ov] exposure portion ( ! *>act]i/ic curve1 ) consequ5t poor r5d]+ ( contra/s4 ,crit]ia ( ,spe$4--,9 airplane photography spe$ is ( p>am\nt importance1 b great c>e mu/ be ex]cis$ to insure t all ! factors are consid]$ :i* c contribute t[>d yield+ ! desirable pictorial quality 9 ! brief exposure :i* alone is possible f ! mov+ plane4 ,a 8fa/0 plate on ! ,h ,d scale is n necess>ily suitable = a]ial "w1 :5 we rememb] t acc5tuation ( natural contra/ is desirable1 p>ticul>ly "u hazy conditions4 ,=1 z is %[n 9 ,fig4 #ajd1 x is a common *>act]i/ic ( 8fa/0 plates to h comp>atively small latitude & l[ contra/ at _! maximum developm5t4 ,x is to be not$ t ! ,hurt] & ,driffield measure ( spe$ is b\nd up ) ! idea ( correct tone r5d]+ & ) ! use ( ! /raight l9e portion ( ! *>act]i/ic curve4 ,o!r crit]ia ( spe$ exi/4 ,= in/ance1 ! exposure necess>y to produce a j noticeable action 7?re%old value72 & ! exposure necess>y to give a *os5 useful d5sity 9 ! high-lights :5 developm5t is pu%$ to ! limit set by ! gr[? ( fog4 ,z has already be5 po9t$ out1 correct tone r5d]+ is n necess>y or ev5 indicat$ z desirable 9 a]ial views4 ,x is1 moreov]1 a matt] ( exp]i5ce t ! majority ( a]ial exposures ) exi/+ plates fall 9 ! 8"u exposure0 p]iod1 :]e contra/s ) normal developm5t are less ?an 9 ! subject4 ,?is be+ ! case1 ! problem is to select n necess>ily a fa/ plate1 by ! ,h ,d crit]ion1 b a plate :i* w develop up workable d5sities 9 ! "u exposure region4 ,a plate ( m$ium spe$ w sometimes develop to great] d5sities 9 ! %ort exposure region1 if developm5t is =c$1 ?an w a fa/ plate4 ,! contra/ 9 ! normal exposure region w be excessive1 b ?is is ( no significance if no exposure fall+ 9 ?is region is pres5t on ! plate4 ,illu/ration3 ,,fig4 #ajd4--;,*>act]i/ic curves ( fa/ & sl[ plates1 develop$ to maximum contra/4 ,9 addition to its capacity = develop+ d5sity1 ! plate %\ld h z l[ a ?re%old z possible1 ?us meet+ to "s ext5t ! requirem5ts ( bo? ! alt]native crit]ia ( spe$ giv5 above4 ,at ! same "t x is true t l[ ?re%old & good d5sity = %ort exposures are n to be f\nd 9 really sl[ plates4 ,consequ5tly1 :ile high spe$1 z ord9>ily und]/ood1 is und\bt$ly ! fir/ requirem5t1 we may expect ! complete specification = ! be/ a]ial plate to be a r complicat$ ?+1 describ+ ! *>act]i/ics ( a workable 8toe0 ( ! curve1 9 t]ms ( :i* sev]al 7e4g41 contra/ & spe$7 are d]iv$ f ano!r & q diff]5t exposure region4 ,effect ( ,temp]ature on ,plate ,spe$4--,x has be5 f\nd by ,abney & ,dew> t v l[ temp]atures mat]ially decrease ! spe$ ( photographic emulsions4 ,?is decrease may am\nt to z mu* z #ej p] c5t4 9 ! temp]ature range f #cj degrees ,c5tigrade above z]o to #cj degrees bel[ z]o1 :i* is ! range ov] :i* a]ial photographic op]ations w h to be c>ri$ on 9 w>-"t4 ,?is effect has n be5 at all fully /udi$1 & x is n kn[n :e!r x is g5]al or only f\nd 9 c]ta9 k9ds ( plates4 ,! rem$y indicat$ is to provide means = heat+ ! plates or films :5 l[ temp]atures are enc\nt]$4 ,?is is fairly easy 9 film cam]as1 or 9 plate cam]as l ! de,ram1 :]e ! entire load ( plates is c>ri$ 9 ! cam]a body4 ,plates c>ri$ 9 magaz9es pres5t a m difficult problem4 ,! heat+ coil incorporat$ 9 ! ,g]man cam]as is p]haps p>tly = ?is purpose4 ,color ,s5sitiv5ess4--,complete specifications = an a]ial plate _c be made solely on ! basis ( its spe$1 contra/1 latitude1 ?re%old1 & o!r s5sitometric values :i* h to d only ) ! int5sity ( ! light act+ on x4 ,^! 9 g5]al apply to photography f l[ altitudes1 :]e ! illum9ation & natural contra/ ( ! subject are ! only factors to consid]4 ,:5 high] altitudes are rea*$ ! int]position ( haze decreases ! already defici5t contra/1 call+ ei!r = ! developm5t ( m contra/ 9 ! plate1 or = ! use ( color filt]s to cut out ! action ( ! blue & violet light pr$om9ant 9 haze4 ,along ! l9es discuss$ 9 ! la/ section1 x is n surpris+ to f9d t "s plates are bett] ?an o!rs = br++ out gradations mask$ by haze1 ev5 ?\gh no filt]s are us$ & ?\gh ! plates are simil> 9 color s5sitiv5ess4 ,b ! limitations to secur+ contra/ by manipulat+ ! *>act]i/ic curve ( ! plate are soon rea*$1 & x becomes necess>y to resort to haze-pi]c+ color filt]s1 us$ ) color s5sitive plates4 ,r\ghly1 two g5]al types ( color s5sitive emulsions may be di/+ui%$3 fir/1 ^? 9 :i* s5sitiv5ess to gre5 & yell[ is add$ to ! natural blue s5sitiv5ess1 & second1 ^? s5sitive 9 a useful degree to all colors ( ! spectrum4 ,! =m] are call$ iso- or or?o-*romatic1 ! latt] pan*romatic emulsions4 ,spectrograms exhibit+ ! di/ribution ( s5sitiv5ess ?r\gh\t ! spectrum = sev]al repres5tative plates are %[n 9 ,fig4 #aje4 ,or?o*romatic plates are adequate = use ) light yell[ filt]s & h ! slight practical work+ advantage t !y c be h&l$ by r$ light4 ,pan*romatic plates are necess>y = use ) d>k orange or r$ filt]s4 ,!y mu/ be h&l$ 9 total d>kness or 9 an exce$+ly fa9t blue-gre5 light1 tak+ advantage ( ! common drop 9 s5sibility 9 t region ( ! spectrum4 ,plates c1 inde$1 be s5sitiz$ = ! r$ alone1 leav+ a gap ( almo/ complete ins5sibility 9 ! gre51 z %[n 9 ! f\r? spectrogram ( ,fig4 #aje4 ,:5 us$ ) a yell[ filt] ^! plates behave z d pan*romatic plates ) a r$ filt]4 ,illu/ration3 ,,fig4 #aje4--,spectrograms ( repres5tative photographic plates3 a1 ord9>y plate2 b1 or?o*romatic plate2 c1 specially gre5-s5sitive plate2 d1 r$ s5sitive plate1 ins5sitive to gre52 e1 pan*romatic plate2 f1 specially r$-s5sitive pan*romatic plate4 ,a r\gh] idea ( color s5sitiv5ess ?an is giv5 by spectrograms is furni%$ by ! tri-color ratio1 :i* is ! ratio ( exposure times necess>y ) :ite light to give equal photographic action ?r\gh a c]ta9 set ( r$1 gre5 & blue filt]s1 express$ 9 t]ms ( ! blue exposure z unity4 ,9 an excell5t pan*romatic plate ! ?ree exposures w\ld be equal4 ,9 an or?o*romatic plate ! r$ exposure w be too l>ge to be figur$4 ,9 int]pret+ ei!r spectrograms or tri-color ratios c>e mu/ be tak5 t ! absolute exposures necess>y are kn[n4 ,?us a relatively high r$ s5sitiv5ess may mean m]ely l[ absolute blue s5sitiv5ess4 ,two me?ods are us$ 9 imp>t+ color s5sitiv5ess4 ,ei!r ! s5sitiz+ dye is incorporat$ 9 ! plate emulsion be=e x is fl[$2 or ! plate is ba!d 9 a dye solution n long be=e us+4 ,! latt] me?od gives high] color s5sitiv5ess b poor] keep+ quality1 & is n a practical me?od = field op]ations4 ,greatly enhanc$ s5sibility may be giv5 by treatm5t ) ammonia1 b ?is aga9 is a me?od = laboratory r ?an field use4 ,resolv+ ,p[]4--,a "q :i* arises 9 connection ) all photography ( detail is ! size ( ! gra9 ( ! photographic emulsion4 ,dep5d5t on ! size ( ! gra9 is ! resolv+ p[]1 or ability to sep>ate images ( closely adjac5t objects4 ,?is v>ies ) ! spe$1 fa/ plates be+ ( co>s] gra9 ?an sl[ ones2 ) ! exposure2 & ) ! me?od & "t ( developm5t4 ,9 g5]al1 x may be said t ! resolv+ p[] ( ! plate does n ent] practically into a]ial "w1 because ! resolv+ p[] ( all plates s f> f\nd usable corresponds to a small] di/ance ?an ! size ( a po9t image z limit$ by ! p]=mance ( ! cam]a l5s & ! spe$ ( ! plane4 ,rememb]+ t mm4 is a fair value = ! size ( a po9t image z r5d]$ by ! l5s1 ! rle ( plate-resolv+ p[] is %[n by consid]ation ( ! foll[+ table4 ,resolv+ p[]s are giv5 9 t]ms ( l9es to ! millimet] j sep>able4 ,emulsion4 ,resolv+ ,p[]4 ,se$ ,graflex #be ,ea/man ,a]ial ,film #cg ,hamm] ,or?o #dd ,cram] ,isonon #dh ,cram] ,spectrum ,process #eg ,ea/man ,portrait ,film #fa ,tabulation ( ,requirem5ts = ,a]ial ,emulsions4--,9 t]ms ( ! s5sitometric quantities j discuss$ ! g5]al requirem5ts = a]ial plates may be li/$ z foll[s3 #a4 ,spe$4 ,! spe$ usually connect$ ) ! contra/ & d5sity requir$ = ! exposure times available is ab\t #aej ,h ,d4 ,fa/] plates 9 g5]al h too l[ contra/1 b ! highe/ spe$ t w give ! necess>y contra/ is desir$4 #b4 ,contra/4 ,! contra/ capable ( developm5t )\t fog %\ld be f #a4e to #b4 ,?is contra/ %\ld be produc$ by light ( daylight quality1 &1 9 or?o*romatic & pan*romatic plates1 ) ! yell[ or orange filt]s int5d$ to be us$ ) !m4 ,?is contra/ means a gamma inf9ity approa*+ #b4e4 #c4 ,spe$ ( developm5t4 ,a gamma ( ne>ly #b %\ld be develop$ 9 #b m9utes at #bj degrees ,c4 9 ! develop]s recomm5d$ bel[4 #d4 ,fog4 ,n ov] 4#be = ?is degree ( developm5t1 & n ov] 4#dj = six m9utes developm5t4 #e4 ,color s5sitiv5ess4 ,?is %\ld 9 g5]al be z high z possible4 ,9 t]ms ( c]ta9 repres5tative filt]s 7describ$ 9 a subsequ5t *apt]7 color s5sitiv5ess %\ld be su* t ) ! :ite light spe$ above specifi$ ! relative exposures ?r\gh ! filt]s %all n be great] ?an z foll[s3 ,no filt] ,a]o #a ,a]o #b #ba #bc;a #be ,pan*romatic plate #a #c #d4e #g #i #ab ,or?o plate #a #b4e #c4e #f ,relative ,behavior ( ,plates & ,films4--,! advantages ( film f ! /&po9t ( weight & bulk h be5 discuss$ 9 connection ) a]ial cam]as4 ,7 !re no o!r consid]ations film w\ld unque/ionably be ! mo/ appropriate m$ium = a]ial photography4 ,!re is1 h[ev]1 ! "q ( ease ( h&l+1 to be treat$ 9 a subsequ5t *apt]1 & ! "q :e!r ! purely photographic *>act]i/ics ( film are satisfactory4 ,c ! same spe$1 contra/1 & color s5sitiv5ess be obta9$ on film z on glass8 ,is ! picture s obta9$ z p]man5t or reliable z ! plate image8 ,x mu/ be confess$ t up to ! pres5t emulsions on film h n prov$ ! equal ( ^? on glass4 ,x has be5 f\nd by emulsion manufactur]s t ! same emulsion fl[$ on film & on glass gives bett] quality on ! glass4 ,emulsions specially prep>$ = film fall some:at %ort ( ! be/ plate emulsions4 ,x has also be5 f\nd h>d] to color-s5sitize film1 & to insure good keep+ quality 9 ! color s5sitiz$ product4 ,9 addition to ! "q ( photographic quality !re arises ! matt] ( %r9kage & di/ortion4 ,^! are negligible ) plates1 b are a m or less unkn[n quantity 9 film4 ,irregul> %r9kages ( z mu* z two p] c5t4 are f\nd on exp]im5t4 ,?is defect1 ( c\rse1 w\ld be an ob/acle only 9 exact mapp+ "w4 ,positype ,pap]4--,! ne$ sometimes arises 9 milit>y op]ations to secure pr9ts ready = exam9ation )9 a few m9utes aft] ! receipt ( ! negatives4 ,ev5 ! #ae or #bj m9utes )9 :i* a negative c be develop$ & a wet pr9t tak5 may be consid]$ too long4 ,:ile su* occasions are probably m apt to occur 9 popul> magaz9e /ories ?an 9 actual w>f>e1 x is important to h available me?ods ( produc+ pr9ts ) an absolute m9imum ( delay4 ,?is ne$ is met to "s degree by a direct pr9t process1 comm]cially exploit$ "u ! "n ( 8,positype40 ,9 ?is process ! exposure is made directly on a s5sitiz$ pap] or c>d1 :i* is develop$1 ! image dissolv$ out1 ! residue expos$1 & aga9 develop$2 ?us furni%+ a positive picture 7rev]s$ "r & left74 ,! "t necess>y to develop a pr9t ready = exam9ation ne$ n be m ?an ?ree m9utes4 ,only a s+le pr9t is available1 b ?is is all t w\ld be call$ = "u ! extreme conditions sugge/$4 ,if lat]1 copies are desir$ !y may be made by ! same process4 ,plates & ,films ,f\nd ,satisfactory = ,a]ial ,"w4--,! foll[+ plates & films h be5 f\nd p>ticul>ly good = a]ial photography4 ,! li/ is n int5d$ to be complete4 ,fur!rmore1 x may be expect$ to be soon sup]s$$1 z ! ef=ts ( v>i\s manufactur]s are direct$ t[>d develop+ special a]ial photographic plates4 ,among or?o*romatic plates3 ,! ,cram] ,comm]cial ,isonon1 ! ,j\gla ,or?o4 ,among pan*romatic plates3 ,! ,il=d ,special ,pan*romatic1 ! ,cram] ,spectrum ,process4 ,film3 ,ansco ,spe$ex1 ,ea/man ,a]o4 ,,*apt] ,,xix ,,filt]s ,! ,function ( ,filt]s 9 ,a]ial ,photography4--,! use ( color scre5s or filt]s has be5 v common 9 ord9>y l&scape photography1 = ! purpose ( secur+ approximately correct r5d]+s ( ! brightnesses ( color$ objects4 ,plates ( ! non-color-s5sitive type h _! maximum ( s5sitiv5ess 9 ! blue ( ! spectrum 7,fig4 #aje7 & 9 consequ5ce blue skies photograph z :ite1 :ile o!r colors are likewise reproduc$ on a totally wrong scale4 ,filt]s = correct brightness r5d]+ are calculat$ = a giv5 color s5sitive plate s t ! resultant reaction to ! light ( ! spectrum copies ! s5sitiv5ess ( ! eye1 :i* is greate/ 9 ! yell[-gre54 ,su* filt]s = use ) ! common or?o*romatic plates are ( a g5]al yell[ color4 ,filt]s = a]ial "w are meant to s]ve q a diff]5t purpose4 ,correct tone or color r5d]+ is ( q second>y importance to ano!r use ( filt]s1 namely1 to cut or pi]ce a]ial haze4 ,x is q a matt] ( accid5t t ! same g5]al color ( filt] is call$ = bo? to give correct color r5d]+ & to pi]ce a]ial haze1 namely1 yell[4 ,yet on clos] analysis x is f\nd t q diff]5t types ( yell[ filt] are dem&$1 spectroscopically consid]$4 ,figure #ajf 7,k#a & ,k#b7 %[s ! spectral transmission curves ( ! ,wratt5 ,k#a & ,k#b filt]s1 int5d$ = correct color r5d]+ ) or?o*romatic plates4 ,! absorption increases gradually t[>d ! blue4 ,9 ! same figure is %[n on an arbitr>y scale ! spectroscopic "* ( typical haze illum9ation1 increas+ 9 brightness inv]sely z ! f\r? p[] ( ! wave-l5g?1 t is1 ) great rapidity 9 ! blue & violet4 ,x is evid5t f ?is t a mu* m abrupt absorption ?an t ( ! ,k#a or ,k#b filt] is desirable1 because 9 ! gre5 ( ! spectrum ! haze light is comp>atively weak1 & m w be lo/ by any absorption 9 ?is region ?r\gh decreas+ useful photographic action ?an w be ga9$ by cutt+ out ! haze4 ,?is latt] consid]ation is important4 ,! use ( any filt] means an increase ( exposure2 ! use ( yell[ filt]s multiplies x sev]al times4 ,c>eful exp]im5t has %[n t no filt] ( dep? less ?an ,k #a1 to use ! ,wratt5 filt]s z a basis = discussion1 are ( real value 9 haze pi]c+4 ,! filt] ratio1 or ratio ( exposures ) & )\t filt]1 is #d4g = ! ,k #a ) ! ,cram] ,isonon plate--a figure :i* %[s ! importance ( secur+ ! necess>y haze-pi]c+ "* ) ! m9imum absorption ( useful photographic light4 ,illu/ration3 ,,fig4 #ajf4--;,*>act]i/ics ( v>i\s filt]s4 ,practical ,filt]s4--,s9ce ! "* ( ! absorption ( ! 8,k0 filt]s is n all t c\ld be desir$1 new filt]s1 bo? ( dy$ gelat9 & ( glass1 h be5 produc$4 ,! glass1 a ,corn+ product hav+ a v %>p-cut absorption1 has n yet be5 produc$ on a comm]cial scale ) ! high transp>5cy 9 gre51 yell[ & r$ t select$ samples h %[n4 ,! ,unit$ ,/ates ,air ,s]vice has adopt$ filt]s ( a new dye1 call$ ! ,,ek1 f ! "n ( ! company 9 ^: laboratory x 0 produc$4 ,^! filt]s are /&>diz$ 9 two dep?s ( /a9+1 call$ ! 8,a]o ,no4 #a0 & 8,a]o ,no4 #b40 ,_! spectral transmission curves appe> 9 ,fig4 #ajf1 along ) ^? ( c]ta9 d>k] filt]s useful only ) pan*romatic plates = exceptionally heavy haze4 ,! *>act]i/ic ( ^! ,a]o filt]s is _! great transp>5cy ?r\gh all ! spectrum except ! blue1 :]eby ! greate/ haze-cutt+ action is atta9$ toge!r ) a l[ filt] factor4 ,! filt] factors ( ! ,a]o ,no4 #a & ,no4 #b ) ,cram] ,isonon plates are #c & #e1 respectively4 ,effects ,secur$ by ! ,use ( ,filt]s4--,! effici5cy ( yell[ filt]s = haze-cutt+ is be/ %[n by photographs tak5 at high altitudes ) filt]s & )\t4 ,su* illu/rations are giv5 9 ,figs4 #ajg & #ajh1 :]e ! fir/ photograph is "o tak5 at #aj1jjj feet )\t a filt]1 ! second tak5 at ! same altitude "u ! same conditions1 b ) an orange filt]4 ,bo? are on pan*romatic plates1 & x w be se5 t ev5 ) ^! plates ! filt] makes all ! diff]5ce betwe5 a useless & a useful picture4 ,b x mu/ be cle>ly und]/ood t ! diff]5ce "h lies betwe5 a plate s5sitive *iefly 9 ! blue & violet1 & a plate affect$ only by ! yell[1 orange & r$4 ,! diff]5ce is n betwe5 :at ! eye sees & :at a plate ) a filt] sees1 z is sometimes suppos$4 ,z %[n 9 ,fig4 #ajh1 a filt] enables ! plate to photograph ?r\gh ! haze betwe5 cl\ds1 b n ?r\gh ! cl\ds !mselves4 ,9 g5]al1 no filt] & plate comb9ation :i* is feasible = a]ial exposures is capable ( %[+ m ?an ! eye c see if yell[ or orange goggles are worn4 ,to d ?is x w\ld be necess>y = ! photographic action to take place by deep r$ or infra-r$ light1 :i* w\ld dem& exposures n[ out ( ! "q4 ,illu/ration3 ,,fig4 #ajg4--;,a photograph tak5 at #aj1jjj feet1 )\t a filt]4 ,filt]s are almo/ always necess>y 9 photograph+ f high altitudes or 9 mak+ di/ant obliques4 ,at times1 p>ticul>ly aft] a heavy ra91 ! air is cle> en\gh s t filt]s may be disp5s$ )4 ,cle>+ wea!r 0 !re=e *os5 :5ev] possible = mak+ obliques ( ! battle front4 ,illu/ration3 ,,fig4 #ajh4--,photograph tak5 at same "t & ov] same neighborhood z ,fig4 #ajg1 b ) an orange filt]4 ,filt]s = ! ,photographic ,detection ( ,cam\flage4--,9 ! photographic z 9 ! visual detection ( cam\flage1 ! problem is to diff]5tiate colors :i* ord9>ily look alike1 b :i* are actually ( diff]5t color composition4 ,p>ticul>ly important are ! diff]5ces betwe5 natural foliage gre5s & ! pa9ts us$ to simulate !m4 ,if ^! diff] 9 _! reflection spectra1 a prop] *oice ( filt] w %[ up ! two gre5s z m>k$ly diff]5t4 ,two k9ds ( diff]5ce may be produc$2 ei!r ! two colors may be *ang$ 9 relative brightness1 or !y may be alt]$ 9 hue4 ,?us foliage gre51 due to its possess+ a reflection b& 9 ! r$ ( ! spectrum1 :i* is abs5t 9 mo/ pigm5ts1 may be made to appe> r$ :ile ! cam\flage rema9s gre5 or turns black4 ,filt]s :i* cause *anges ( color are ( c\rse ( no use = photographic detection ( cam\flage1 s9ce ! photographic image is colorless4 ,brightness diff]5ces are alone available4 ,^? same filt]s :i* h be5 work$ out prim>ily = produc+ brightness diff]5ces 9 visual detection ( cam\flage c\ld be us$ photographically1 provid$ ! plates employ$ 7 color s5sitive1 & 7 z well scre5$ to imitate ! s5sibility ( ! eye4 ,b ! mo/ useful visual filt]s are ^? caus+ color diff]5ces to appe>2 m ?an ?is1 ! visual cam\flage detection filt]s z a class h l[ light transmissions1 s t _! usefulness 9 photography is d\btful4 ,little "w has actually be5 done ) cam\flage detection filt]s = photography4 ,yet 9 spite ( ?is photography has be5 ( real s]vice 9 ?is =m ( detective "w4 ,its utility = ! purpose comes f ! fact t ! natural s5sitiv5ess ( ! plate to blue1 violet & invisible ultra-violet acts to ext5d ! range ( ! spectrum 9 :i* diff]5ces betwe5 id5tical & m]ely visually mat*$ colors may be pick$ up4 ,consequ5tly ! pla9 unscre5$ plate has prov$ a v effici5t cam\flage detector--s effici5t 9 fact t all cam\flage mat]ials h _h to be subject$ to a photographic te/ be=e acceptance4 ,fig4 #aga %[s h[ an ord9>y photograph reveals ! unnatural "* ( ! cam\flage ov] a batt]y4 ,me?ods ( ,m\nt+ & ,us+ ,filt]s4--,! mo/ primitive way ( m\nt+ a gelat9 filt] is to cut a disc f a %eet ( dy$ gelat9 & ins]t x betwe5 ! compon5ts ( ! l5s4 ,= ?is purpose ! gelat9 mu/ be p]fectly flat1 :i* is insur$ by its me?od ( prep>ation & te/4 ,"o disadvantage ( ?is me?od is t ! filt] c be ins]t$ & remov$ only ^u ! gr\nd4 ,x is less satisfactory ! l>g] ! diamet] ( ! l5s1 & ! wa/age ( filt]s due to ins]tion & removal is apt to be high4 ,! cam]a %\ld be refocuss$ aft] filt]s ( ?is k9d are ins]t$4 ,glass filt]s1 gr\nd optically true1 or gelat9 filt]s1 m\nt$ betwe5 optically flat glass plates1 are ! mo/ conv5i5t & satisfactory4 ,!y may be m\nt$ 9 circul> cells to screw or atta* by bayonet cat*es to ! front ( ! l5s4 ,or !y may be m\nt$ 9 rectangul> frames to slide into transv]se grooves 9 ! cam]a body4 ,fig4 #dd %[s ! m\nt ( ?is latt] =m adopt$ 9 ! l>g] ,unit$ ,/ates ,air ,s]vice cam]as4 ,?is is p>ticul>ly conv5i5t if x is desir$ to ins]t or *ange ! filt] :ile 9 ! air--a practice n g5]ally consid]$ feasible 9 w> "w ) ! photographically inexp]i5c$ obs]v]1 b likely to be common ) ! employm5t ( skill$ photograph]s = peace-"t a]ial photography4 ,g]man cam]as are report$ 9 :i* ! glass filt] is c>ri$ beh9d ! l5s1 on a lev] :i* also c>ries a cle> glass plate ( ! same ?ickness1 to be ?r[n 9 :5 no filt] is ne$$1 ?us ma9ta9+ ! focus4 ,! p]=mance ( ! l5s w be impair$ by ?is s*eme1 unless x is specially calculat$ to (fset ! effect ( ! glass introduc$ 9 ! pa? ( ! rays beh9d ! l5s--optically true glass has no effect on def9ition if plac$ 9 front ( ! l5s4 ,glass filt]s may also be plac$ 9 close contact ) ! plate or film1 9 :i* case !y mu/ be mu* l>g]1 b d n ne$ to be ( z good optical quality4 ,self-scre5+ ,plates4--,m5tion mu/ be made ( a q diff]5t mode ( realiz+ ! filt] idea1 a me?od available :]e ! s5sitive plate is always to be us$ ) a filt]4 ,?is is to incorporate a yell[ dye 9 ! gelat9 ( ! plate itself4 ,! dye mu/ be "o :i* has no direct *emical effect on ! plate1 b :i* acts simply z a color+ ag5t = ! gelat94 8,self-scre5+0 plates1 z !y are call$1 h be5 produc$ by ! use ( ! dye call$ 8filt] yell[0 & h f\nd "s use 9 or?o*romatic photography4 ,!y effect a useful sav+ ( light ?r\gh ! elim9ation ( ! reflection losses at ! surfaces ( glass & gelat9 filt]s4 ,! filt]+ action ( ! dye 9 ! plate is some:at diff]5t f its ord9>y "o1 s9ce ! deep] portions ( ! s5sitive film are subject to great] action ?an ! surface1 & ?is t5ds to dim9i% contra/4 ,,*apt] ,,xx ,,exposure ,,( ,,a]ial ,,negatives ,! pr9cipal factors gov]n+ ! l5g? ( exposure 9 ! airplane cam]a h already be5 discuss$ "u v>i\s head+s4 ,^! are briefly1 ! nature ( ! a]ial l&scape1 ! practically atta9able l5s ap]tures1 ! =m ( ! cam]a support1 ! spe$ ( ! plane1 & ! *>act]i/ics ( plates1 films & filt]s4 ,x is conv5i5t h[ev]1 to re-assemble ?is in=mation 9 "o place1 9 su* =m z to apply to ! practical problem ( det]m9+ ! exposure to be giv5 9 any specific case4 ,limitations to ,exposure4--,9 ! ord9>y photography ( /ation>y objects1 exposure is a v>iable entirely at ! op]ator's comm&4 ,plates ( any spe$ may be select$1 s t att5tion may be focuss$ on latitude1 color s5sitiv5ess1 & o!r tone r5d]+ *>act]i/ics4 ,! exposure may be made ( a l5g? suffici5t to insure all ! useful photographic action ly+ 9 ! 8correct exposure0 portion ( ! s5sitometric curve4 ,! exposure ratio ( any filt] x is desir$ to use is a matt] ( indiff]5ce--its effect on color r5d]+ ne$ alone be consid]$4 ,airplane photography is %>ply di/+ui%$ f gr\nd 8/ill0 photography by its sev]e limitations z to ! am\nt ( ! exposure4 ,! actual duration is def9itely re/rict$ by ! high spe$ ( ! plane4 ,9 peace "w ?is c be (fset 9 "p by us+ sl[] planes or by fly+ aga9/ ! w9d4 ,! practical limitation to #a_/ajj second1 set by w>-"t requirem5ts z to def9ition ( f9e detail1 may be increas$ to #a_/ej ( a second1 or ev5 m1 :]e mapp+ ( gross] features is ! object4 ,a common1 b entirely avoidable limitation1 is t due to vibration ( ! cam]a4 ,by prop] m\nt+ ?is may be entirely ov]come1 leav+ ! gr\nd spe$ ( ! plane ! only s\rce ( exposure-limit+ movem5t4 ,! am\nt ( light rea*+ ! plate con/itutes a prim>y factor 9 exposure1 & ?is is a matt] ( l5s ap]ture4 ,g5]ally1 l5s ap]ture is small] ! l>g] ! plate requir$ to be cov]$1 & ! great] ! focal l5g?4 ,because ( _! l>g] ap]ture1 ! %ort-focus l5ses :i* w be favor$ = peace-"t l>ge-area mapp+ w p]mit m & long] work+ days ?an h be5 ! rule 9 long-focus w> photography4 ,! necess>y use ( filt]s1 p>ticul>ly at ! high altitudes :i* w\ld be *os5 9 mapp+1 9 ord] to economize 9 ! numb] ( flights ne$$ to cov] a giv5 area1 introduces an inevitable decrease 9 ! am\nt ( light available at ! plate1 z comp>$ ) surface photography "u ! same illum9ations4 ,broadly speak+1 x may be said t all ! dem&s made 9 ref]5ce to a]ial photographic exposure "w are to decrease ! am\nt ( light rea*+ ! plate4 ,any surplus (f]$1 z by ! midsumm] noon-day sun1 mu/ be imm$iately snapp$ up1 ei!r by decreas+ ! exposure to get great] %>pness1 or by introduc+ filt]s to get great] photographic contra/4 ,! absolute exposure ( ! plate t5ds to be kept at ! irr$ucible m9imum4 ,z already /at$1 x lies1 ) pres5t photographic mat]ials1 on ! 8toe0 ( ! 8,h ,d0 curve1 j rea*+ up into ! /raight l9e portion4 ,e/imation ( ,exposure4--,accord+ to ! =ego+ argum5t ! problem ( e/imat+ an a]ial exposure resolves itself l>gely into "o ( decid+ h[ %ort ?is may be made4 ,or1 if ! light is /rong1 :e!r x is suffici5t s t a filt] may be introduc$ )\t dem&+ m ?an ! #a_/ajj second or !reab\ts :i* is dictat$ by ! motion ( ! plane4 ,decid+ ^u exposures 9 ! field has be5 l>gely a matt] ( exp]i5ce & judgm5t4 ,a majority ( ! cam]as 9 use dur+ ! w> 7 n furni%$ ) %utt]s calibrat$ 9 def9ite spe$s4 ,consequ5tly1 ! s]geant ^u :om ! decision usually devolv$ became a /oreh\se ( k z to ! slit wid?s & t5sions appropriate to ea* individual cam]a4 ,?is k _h to be acquir$ f ! results ( actual photographic reconnaissances1 or f special te/ flights1 bo? ( !m wa/eful me?ods4 ,b ! *ief objection to ?is /ate ( affairs lies 9 ! fact t ! k ?us acquir$ is ( no use to anyone else1 nor is x applicable to o!r types ( cam]a4 ,! fir/ ess5tial to plac+ exposure e/imation ^u a s\nd basis is !re=e an accurate k ( %utt] p]=mances4 ,ei!r ! %utt] spe$s %\ld be plac$ ^u ! cam]a by ! manufactur] & p]iodically *eck$1 or a regul> practice %\ld be foll[$ ( calibrat+ %utt]s1 ei!r at a base laboratory or ev5 9 ! field4 ,assum+ t ! spe$s ( all %utt]s are accurately kn[n1 ! process ( e/imat+ ! requisite exposure becomes less a matt] ( m]e guesswork & m ne>ly a matt] ( precision4 ,= ?is purpose data on ! v>iation ( light int5sity dur+ ! day & dur+ ! ye> 7,figs4 #aja & #ajb7 %\ld be tak5 z a guide4 ,^! data ref] ( c\rse to visual & n to photographic light1 b s9ce x is always necess>y to use color filt]s1 :i* make ! active light ( approximately visual quality1 ?is is no valid objection4 ,! effects ( cl\ds & mi/ mu/ ( c\rse be le>n$ l>gely by exp]i5ce1 b ) ! above daylight data at h&1 anyone 9 possession ( def9ite in=mation on ! correct exposure ) a giv5 plate = a kn[n day & h\r ne$ n g f> wrong 9 e/imat+ exposures at any o!r "t 9 def9ite fractions ( a second4 ,illu/ration3 ,,fig4 #aji4--;,*>t %[+ a]ial exposures = all times ( ! day & ye>4 ,data on basis ( ,f_/#e4f l5s1 ,j\gla or?o*romatic plate1 & cle> sunlight1 no filt]4 ,exposures to be d\bl$ & tripl$ = ov]ca/ & cl\dy wea!r4 ,exposure data *>ts4 ,fig4 #aji %[s a *>t1 prep>$ 9 ! ,fr5* s]vice1 indicat+ a]ial exposures = all h\rs ( ! day ?r\gh\t ! ye>4 ,^! are = cle> sunlight1 = a l5s ( ap]ture ,f_/#e4f & = 8or?o0 plates )\t a filt]4 ,!y are bas$ on :at is probably an ov]-e/imate ( ! actual spe$s giv5 by ! ,fr5* %utt]s4 ,= 8light0 cl\ds ! exposures are to be d\bl$1 = 8heavy0 cl\ds quadrupl$1 & = =e/s & d>k gr\nd 8l5g!n$40 ,*>ts ( ?is =m %\ld be extremely useful1 b !y 7 actually n ( great s]vice because ( ! preval5t lack ( k ( true %utt] spe$s4 ,exposure met]s4 ,a]ial photography (f]s an excell5t opportunity = ! use ( exposure met]s1 p>ticul>ly ^? ( ! type 9 :i* a s5sitive surface is expos$ to ! light = a measur$ "t suffici5t to d>k5 a pr$et]m9$ am\nt4 ,! s5sitive pap] ( ! met] may ei!r be expos$ f ! gr\nd to ! direct light ( sun & sky1 or f ! plane to ! light reflect$ f ! gr\nd4 ,! fir/ me?od w give figures subject to "s correction = ! "* ( ! gr\nd to be photograph$--:e!r fields1 =e/s1 or sn[4 ,! second me?od is to be pref]r$ :]e ! %utt] spe$ c be adju/$ 9 ! air1 accord+ to ! indications ( ! met]1 or :]e ! filt] c be select$ & put 9 place dur+ flight4 ,trials ) a comm]cial ,wynne exposure met]1 us$ 9 ! latt] mann]1 give z a work+ figure an exposure ( 4#jja second = ea* #d seconds tak5 to d>k5 ! s5sitomet] /rip to mat* ! d>k] comp>ison pat*4 ,?is relation applies to a l5s ( ap]ture ,f_/#d4e1 on ,cram] ,comm]cial ,isonon plates )\t filt]4 ,,*apt] ,,xxi ,,pr9t+ ,,m$ia ,skill$ photograph]s c exam9e a negative & c int]pret its r5d]+s ) practically z mu* satisfaction z !y get f a pr9t1 :]eby a consid]able am\nt ( "t c be sav$ 9 an em]g5cy4 ,! orig9al glass negative %\ld always be us$ :5 accurate measurem5ts are to be made4 ,^! & a few o!r cases con/itute ! only use ( a negative ap>t f its normal "o1 namely1 = produc+ positive pr9ts1 usually 9 l>ge numb]s4 ,! commone/ =m ( pr9t is on pap]1 al?\gh ! mo/ satisfactory pr9t f ! photographic /&po9t is ! transp>5cy on glass or celluloid film4 ,transp>5cies4--,transp>5cies are made by ! regul> photographic processes ( exposure & developm5t1 on glass plates or films plac$ 9 contact ) ! negative1 or 9 ! appropriate position 9 an enl>g+ cam]a4 ,! s5sitometry & ! t]ms us$ to describe ! qualities ( plate or film = ?is purpose are ^? already giv5 9 connection ) ! g5]al discussion ( plates & films4 ,b ! k9d ( emulsion to be select$ is q diff]5t f ! a]ial negative emulsion4 ,!re is "h no practical limitation to ! spe$1 contra/ or latitude4 ,consequ5tly1 we c *oose a positive emulsion on :i* ! exposure ?r\gh ! a]ial negative falls entirely on ! /raight l9e portion ( ! *>act]i/ic curve1 ?us reproduc+ all ( its tones1 & ! contra/ ( ! negative may be increas$ to any desir$ ext5t4 ,! possibilities ( positive emulsion are inde$ r great] ?an ! usual a]ial negative c utilize4 ,a range ( cle>ly graduat$ opacities ( two or ?ree hundr$ to "o is possible1 s t n only c detail be well r5d]$ 9 ! high-lights1 b also equally well 9 d>k %ad[s :]e1 inde$1 an increase ( illum9ation is necess>y = x to be made easy to exam9e4 ,?is range is to be contra/$ ) ! #a-to-#g range 9 ! a]ial l&scape1 :i* may be d\bl$ by a contra/y plate4 ,9 resolv+ p[]1 ! positive emulsion1 :i* is sl[1 exce$s ! negative emulsion4 ,x easily be>s exam9ation ?r\gh a magnify+ glass1 ?us mak+ any enl>gem5t unnecess>y 9 ! pr9t+ process4 ,glass transp>5cies are ( c\rse impractical = g5]al di/ribution1 on acc\nt ( _! fragility4 ,heavy film transp>5cies are n op5 to ?is objection1 &1 especially 9 ! =m ( /]eos1 con/itute ! mo/ beautiful =m ( a]ial photographic pr9t4 ,pap] ,pr9ts4--,pr9ts on pap] suff] by comp>ison ) transp>5cies1 9 ! range ( tones :i* !y exhibit4 ,?is lies betwe5 ! :ite ( ! pap]1 :i* nev] has m ?an #hj p] c5t4 reflect+ p[]1 & its d>ke/ black1 :i* diff]s ) ! k9d ( pap]4 ,9 dull or mat pap]s ! blacks w reflect z mu* z #e p] c5t42 9 glossy pap]s1 ord9>ily us$ = a]ial negatives1 ! reflection f ! black may be z l[ z "o p] c5t41 b 9 ord] to get ! b5efit ( ?is ! pap] mu/ be s held z n to reflect any bright object to ! eyes4 ,?is defici5cy 9 ! range ( pap] gradations is n s s]i\s ) a]ial negatives z ) ord9>y prop]ly expos$ negatives because ( ! small range ( brightness 9 ! a]ial view4 ,! s5sitometry ( pap]s is simil> to t ( plates1 ) ! diff]5ce t reflect+ p[]s take ! place ( transp>5cy4 ,z 9 ! case ( transp>5cy emulsions !re is 9 pap]s no dom9at+ requirem5t = extreme spe$1 to :i* o!r *>act]i/ics mu/ be subord9at$4 ,yet spe$ is ( suffici5t importance 9 h&l+ l>ge quantities ( pr9ts s t a]ial negative pr9t+ = milit>y purposes has be5 done almo/ entirely on ! rapid enl>g+ pap]s1 r ?an on ! true contact pr9t+ pap]s1 :i* are sl[]4 ,illu/ration3 ,,fig4 #aaj4--;,*>act]i/ic curves ( bromide pap]4 ,! two pr9cipal types ( rapid enl>g+ pap]s1 ! bromide & ! 8gas light10 exhibit c]ta9 *>act]i/ic diff]5ces :i* are important to be> 9 m9d 9 seek+ to obta9 any p>ticul> quality ( pr9t4 ,bromide pap]s1 ( :i* 8,nikko0 is a good example1 %[ s5sitometric curves r l ^? ( plates4 ,t is1 !y increase 9 contra/ ) cont9u$ developm5t4 ,at ! same "t1 z is %[n 9 ,fig4 #aaj1 !y increase some:at 9 spe$ ) developm5t2 t is1 "u exposure c be comp5sat$ = to a small degree by protract$ developm5t4 ,^! *>act]i/ics ( bromide pap] c be utiliz$ to secure pr9ts ( a quality q diff]5t f t ( ! negative4 ,?us1 if ! negative has a long range ( tones1 a flat pr9t c be secur$ by full exposure & %ort developm5t4 ,if1 z is apt to be ! case ) a]ial negatives1 a pr9t ( great] contra/ ?an ! negative is desir$1 a %ort exposure ) long developm5t is call$ =4 ,illu/ration3 ,,fig4 #aaa4--;,*>act]i/ic curves ( gas light pap]4 ,! s5sitometric curves ( a typical gas light pap] 8,contra/ ,enl>g+ ,cyco10 are %[n 9 ,fig4 #aaa4 ,"h ! contra/ is a fix$ *>act]i/ic ( ! pap]1 & ! only effect ( *ang+ developm5t is on ! spe$2 t is1 exposure & developm5t are1 )9 limits1 int]*angeable4 ,*oos+ a pr9t+ pap] is a matt] ( decid+ on ! contra/ requir$ = ! class ( negative1 & select+ a pap] :i* w give ?is contra/ ) a good range ( tones f a cle> :ite to a deep black4 ,! ideal pap] w\ld be "o :i* 0 all /raight l9e 9 ! ,h ,d plot4 ,9 su* a pap] !re w\ld occur no loss ( contra/ 9 ! light] tones :5 ! high-lights 7 r5d]$ by ! cle> :ite ( ! pap]4 ,too great contra/ ) a %ort /raight l9e portion1 results 9 loss ( detail at ! ends ( ! scale4 ,a negative possess+ a v great range ( tones _c be correctly repres5t$ on "o pap] pr9t--two pr9t+s are requir$1 "o = high-lights & "o = %ad[s1 b ?is difficulty is r>ely to be fac$ 9 a]ial views4 ,! greate/ dem& = a]ial pr9t+ pap]s has be5 = ^? ( consid]able contra/1 because ( ! flat "* ( ! negatives4 ,,*apt] ,,xxii ,,photographic ,,*emicals ,g5]al ,consid]ations4--,develop+1 fix+ & o!r *emicals = a]ial "w diff] 9 no ess5tial respect f ^? us$ 9 ord9>y photography4 ,full discussions ( ^! are to be f\nd 9 num]\s texts & articles4 ,! a]ial photographic problem is to select ^? mo/ suit$ = ! "u-expos$ flat negatives *>act]i/ic ( photographs f ! air4 ,at ! same "t selection f among ! *emicals ( appropriate quality mu/ be gov]n$ by consid]ations ( ! conditions surr\nd+ "w 9 a]ial photographic laboratories4 ,^! laboratories1 especially 9 w>-"t1 are apt to be mo/ primitive 9 _! facilities4 ,*>act]i/ics ( ,develop]s = ,plates & ,films4--,f ! /&po9t ( practicability1 a]ial negative develop]s %\ld h good keep+ p[]1 be sl[ to exhau/1 & "w well ov] a consid]able range ( temp]atures4 ,f ! /&po9t ( ! photographic quality desir$ 9 ! negative1 ! develop] %\ld br+ up ! maximum am\nt ( "u-expos$ detail4 ,?is means t x %\ld imp>t ! highe/ possible spe$ to ! plate1 ) good contra/1 & l[ fog or g5]al r$uction ( unexpos$ silv] bromide4 ,!re are _m *>act]i/ics to /udy 9 a develop]3 its effect on in]tia or spe$1 gamma inf9ity1 fog1 "t ( appe>ance1 8,watk9s factor10 spe$ ( developm5t1 temp]ature coeffici5t1 dilution coeffici5t1 keep+ p[]1 exhau/ion1 l5g? ( r9s+1 /a91 color coeffici5t & resolv+ p[]4 ,^! are def9$ & describ$ z foll[s3 ,effect on in]tia4 ,! mean+ ( in]tia has already be5 giv5 "u ! discussion ( plate spe$4 ,:ile ?is is a con/ant1 indep5d5t ( "t ( developm5t1 = any "o develop]1 x is alt]$ appreciably by *ange ( ! latt]4 ,"t-gamma relation4 ,contra/1 symboliz$ by 1 has likewise be5 discuss$ "u plate s5sitometry4 ,view$ f ! /&po9t ( ! develop]1 ! po9t ( int]e/ is ! rate at :i* v>ies ) developm5t1 & ! maximum contra/ :i* c be rea*$ or inf9ity4 ,spe$ ( developm5t is commonly def9$ by ! velocity con/ant1 symboliz$ by 1 :i* is arriv$ at ma!matically f a consid]ation ( ! "t ( developm5t to produce two diff]5t contra/ values4 ,high inf9ity is desir$ = a]ial negatives1 & = rapid "w mu/ also be high4 ,fog4 ,! opacity due to *emical fog is to be kept at a m9imum 9 a]ial negatives1 z x is *iefly prejudicial to "u exposures4 ,"t ( appe>ance & ,watk9s factor4 ,! "t ( appe>ance is measur$ 9 seconds4 ,! ,watk9s factor is a practical measure ( ! spe$ ( developm5t1 & is det]m9$ by ! ratio ( ! "t ( developm5t requir$ = a def9ite contra/1 to ! "t ( appe>ance4 ,x is useful also z a guide to developm5t "t4 ,temp]ature coeffici5t4 ,?is is ! factor by :i* ! "t ( developm5t at normal temp]ature 7#bj ,c5t47 mu/ be increas$ or decreas$ 9 ord] to obta9 ! same quality negative1 = a *ange ( sev5 degrees ei!r side ( normal4 ,temp]ature limits are ! temp]atures betwe5 :i* developm5t c be c>ri$ out ) any degree ( control or )\t s]i\s damage to ! negative4 ,^! factors are ( great importance :]e climatic or seasonal *anges h to be endur$4 ,dilution coeffici5t4 ,?is is ! factor by :i* ! developm5t "t is increas$ 9 ord] to ma9ta9 a giv5 quality negative 9 diff]5t dilutions ( ! develop]4 ,x is useful 9 tank developm5t4 ,keep+ p[]4 ,! keep+ p[] ( a develop]1 mix$ ready = use1 is det]m9$ by its ability to resi/ a]ial oxidation4 ,a develop] ( poor keep+ p[]1 :i* mu/ be made up imm$iately be=e use1 causes delay & wa/e ( "t :5ev] em]g5cy "w has to be done1 :]eas a develop] ( good keep+ p[] may be left 9 its tank ready = in/ant use4 ,exhau/ion ( a develop] is ! rate at :i* x becomes useless = develop+1 due bo? to a]ial oxidation & to ! us+ up ( its r$uc+ p[] by ! "w done 9 develop+ plates4 ,x is conv5i5tly measur$ by ! area ( plate surface developable be=e ! solution mu/ be r5ew$4 ,l5g? ( r9s+4 ,! "t requir$ = r9s+ betwe5 developm5t & fix+ ba? plays a n unimportant "p 9 total developm5t "t4 ,di*roic fog is caus$ ) "s develop]s if1 due to insuffici5t r9s+1 any ( ! cau/ic alkali is c>ri$ ov] to ! fix+ ba?4 ,/a9s develop also if ! fix+ ba? is old1 or if light falls on ! unfix$ plate :ile any develop] rema9s 9 ! film4 ,color coeffici5t4 ,! function ( ! sulphite1 :i* =ms a con/itu5t ( all develop+ solutions1 is two-fold4 ,x acts p>tly z a pres]vative1 & p>tly to prev5t ! occurr5ce ( a yell[ color 9 ! deposit4 ,! yell[ color1 if pres5t1 increases ! photographic contra/4 ,?is ph5om5on has be5 purposely utiliz$1 p>ticul>ly 9 ! ,briti% s]vice1 to give 8/a90 to negatives :i* o!rwise w\ld %[ insuffici5t pr9t+ d5sity4 ,! color index or coeffici5t ( a negative 7) a giv5 pr9t+ m$ium7 is ! ratio ( photographic to visual d5sity4 ,if we take a pyro develop] conta9+ five p>ts ( pyro p] ?\s& & t5 p>ts ( sodium c>bonate1 & !n v>y ! am\nt ( sulphite f none to fifty p>ts p] ?\s&1 ! color index v>ies z foll[s3 ,sulphite ,color ,index ,p>ts p] ,?\s& #ej #a4af #be #a4bd #ae #a4cj #aj #a4de #e #a4hj #j #b4ge ,! color index is some:at diff]5t ) v>i\s k9ds ( pr9t+ m$ia4 ,?is /a9+ effect is a v>iable "o1 dep5d+ ^u l5g? ( developm5t1 dilution ( ! develop]1 l5g? ( r9s+1 temp]ature1 ! fix+ ba? us$ 7pla9 hypo be+ necess>y = a maximum effect71 ! l5g? ( wa%+ aft] fixation & ! prop]ties ( ! wat] us$4 ,/&>dization ( ^! conditions 9 ! field is difficult2 h5ce any develop] :i* w give ! same effective contra/ )\t resort+ to /a9 is to be pref]r$4 ,resolv+ p[]4 ,"s develop+ processes & conditions w introduce bad gra9 into ! negative4 ,h5ce ! resolv+ p[] :i* a develop] br+s up mu/ be inve/igat$ among its o!r *>act]i/ics4 ,practical ,develop]s = ,a]ial ,negatives4--,9 ! ,engli% s]vice a pyro metol develop] 0 g5]ally us$1 produc+ /a9$ negatives4 ,! ,fr5*1 ,am]ican & ,italian practice 0 to use metol-hydro*9on1 )\t /a9+4 ,a special *lor-hydro*9on develop]1 work$ out by ! ,ea/man ,rese>* ,laboratory = ! ,unit$ ,/ates ,air ,s]vice1 has probably ! greate/ m]it ( any yet tri$4 ,a comp>ison1 giv5 bel[1 betwe5 x & a pyro metol =mula us$ on a repres5tative plate1 illu/rates ! use ( ! v>i\s bases ( /udy giv5 above4 ,,pyro ,,=mula ,solution ,a ,solution ,b ,pyro1 #c4ge grams ,sodium c>bonate1 #ec g ,potassium metabisulphite1 #c4ge g ,metol1 #c4je g ,potassium bromide1 #a4e g ,wat]1 #ejj c4c4 ,wat]1 #ejj c4c4 ,use #a "p ( ,a to #a ( ,b ,,*lorhydro*9on ,,=mula ,solution ,a ,solution ,b ,*lorhydro*9on1 #be g ,sodium c>bonate1 #cj g ,metol1 #f g ,sodium hydrate1 #aj g ,sodium bisulphite1 #b4e g ,potassium bromide1 #c g ,sodium sulphite1 #be g ,wat] to #fgj c4c4 ,wat] to #ccj c4c4 ,use #b p>ts ( ,a to #a ( ,b ,pyro ,*lorhydro*9on ,h ,d spe$ #aej #ahj ,gamma inf9ity #a4de #b4ab ,fog 7at maximum gamma7 4#cb 4#fj ,"t ( appe>ance #e seconds #e seconds ,watk9s factor #be #aj ,velocity factor 80 4#cbj 4#djj ,temp]ature coeffici5t #a4dj #b4j ,temp]ature limits #d to #cb ,c #d to #cb ,c ,keep+ p[] #de m9utes #h days ,exhau/ion 7#ajj c4c47 #cj sq4 94 #cjj sq4 in*es ,dilution coeffici5t #b #b ,color coeffici5t #a4ej #a4jj ,resolv+ p[] #dg #ec ,ow+ to ! difficulty ( secur+ pure *lor-hydro*9on a metol hydro*9on ( v simil> prop]ties has be5 work$ out4 ,its composition is ,metol #af grams ,hydro*9on #af grams ,sodium sulphite #fj grams ,sodium hydroxide #aj grams ,potassium bromide #aj grams ,wat] to #a litre ,to keep ! +r$i5ts 9 solution 9 cold wea!r1 #ej c4c4 ( alcohol %\ld be includ$ 9 e litre ( solution4 ,all ?+s consid]$ ?is is probably ! mo/ practical & satisfactory develop] = a]ial negatives4 ,develop]s = ,pap]s4--,! foll[+ =mula has be5 f\nd v satisfactory = pap]s3 ,metol 4#i gram ,hydro*9on #c4f gram ,sodium c>bonate #bj4j gram ,sodium sulphite #ad4j gram ,potassium bromide 4#e to #a4j gram ,wat] to #a litre ,fix+ ,ba?s4--,= plates ! foll[+ fix+ & h>d5+ ba? is recomm5d$3 ,sodium ?iosulphate 7hypo7 #cej grams ,potassium *rome alum #f grams ,sodium bisulphite #aj grams ,wat] to #ajjj c4c4 ,dur+ hot wea!r1 ! above quantities ( *rome alum & bisulphite are d\bl$4 ,= pap]s ! foll[+3 ,hypo1 #ce p] c5t4 #ajj volumes ,acid h>d5] #e volumes ,! acid h>d5] is con/itut$ z foll[s3 ,alum #ej grams ,acid acetic #bh #djj c4c4 ,sodium sulphite #ajj grams ,wat] to #a litre ,int5sification & ,r$uction4--,^! processes h be5 little employ$ 9 air "w4 ,r$uction is r>ely necess>y1 = obvi\s reasons4 ,int5sification w\ld (t5 be ( value1 b ! common practice1 :i* saves "s "t1 is to use pr9t+ pap] ( /rong contra/ = ^? negatives :i* are defici5t 9 d5sity & contra/4 ,:5 int5sification is desirable or p]missible1 ei!r ! ord9>y m]cury or uranium int5sifi] may be us$4 ,wat]4--,9 ! field x is f\nd necess>y 9 _m cases to purify ! wat] t is to be us$ 9 mix+ up *emicals4 ,wat] may conta9 susp5d$ matt] or dirt1 dissolv$ salts1 & slime4 ,x is important to remove ! susp5d$ matt]1 z x may cause spots on ! plates & pap]s1 :ile any slime w\ld coagulate1 =m+ a sludge 9 ! develop] :i* w\ld also t5d to settle on ! plates & cause m>ks dur+ developm5t4 ,! dissolv$ salts may or may n cause tr\ble4 ,two me?ods ( purification are possible3 7a7 ,filt] ! wat] ?r\gh a clo? into a b>rel1 add ab\t "o gram ( alum = e f\r litres ( wat]1 & all[ to settle ov] night4 ,draw (f ! cle> liquid f a plug 9 ! side z requir$4 7b7 ,boil ! wat] & all[ x to cool ov] night4 ,if ! wat] conta9s dissolv$ lime1 boil+ w (t5 cause ?is to come out ( solution4 ,v ,,me?ods ,,( ,,h&l+ ,,plates1 ,,films ,,& ,,pap]s ,,*apt] ,,xxiii ,,! ,,develop+ ,,& ,,dry+ ,,( ,,plates ,,& ,,films ,field ,requirem5ts4--,develop+1 fix+1 dry+ & pr9t+ 9 ! field dem& simple & conv5i5t app>atus t may be c>ri$ ab\t & in/all$ ) ! lea/ am\nt ( labor4 ,on top ( ^! requirem5ts milit>y ne$s impose o!rs t are m difficult4 ,spe$ is1 on occasion1 imp]ative4 ,a pr9t may be requir$ )9 a few m9utes aft] l&+1 & _m ?\s&s )9 a few h\rs4 ,quantity production mu/ be a*iev$ "u ! mo/ primitive conditions4 ,no?+1 9 fact1 %[s ! calibre ( ! photographic (fic] bett] ?an 8 *oice ( workplaces z ! army moves =w>d4 ,+5uity & practical judgm5t are at a premium4 ,cell>s1 /ables1 dog k5nels1 or huts ha/ily built f pack+ cases1 mu/ be equipp$ & 9 work+ ord] ov] night4 ,all ! facilities (f]$ by a great city are urg5tly ne$$--wat]1 electric light1 p[] = driv+ fans--b mu/ be disp5s$ ) if ! photographic section is to be conv5i5t to ! airdrome1 ^: portable hang>s are mo/ apt to be pit*$ 9 ! op5 c\ntry4 ,wat] mu/ be c>ri$1 electricity g5]at$1 & to ! photographic problem is add$ ! milit>y "o ( concealm5t & protection4 ,dug\ts & bomb pro(s mu/ be built = supplies1 & 8funk holes0 = ! m54 ,entire und]gr\nd em]g5cy ext5sions h sometimes be5 built 9 /ations occupi$ = ext5d$ p]iods1 = airdromes are a favorite bomb+ t>get4 ,= gett+ ! expos$ plates to ! photo section1 mess5g]s1 on motorcycles if possible1 are employ$4 ,9 "s cases1 :]e hang>s & photographic hut are =c$ to be widely sep>at$1 rec\rse has be5 _h to p>a*utes 7,fig4 #aab71 a device also employ$ to di/ribute pr9ts to infantry dur+ an advance4 ,illu/ration3 ,,fig4 #aab4--,receiv+ pictures f plane by p>a*ute4 ,= w>f>e ( movem5t1 especially 9 sp>sely settl$ or deva/at$ c\ntry1 :]e cell>s are unavailable1 ! d>k room mu/ be tak5 along4 ,motor trucks & trail]s 7,figs4 #aac1 #aad1 #aae71 ! =m] = haul+ supplies & electric light g5]at+ plant1 ! latt] fitt$ z a complete develop+ & pr9t+ laboratory1 =m ! headqu>t]s ( ea* photographic section 9 ! field4 ,usually altoge!r too small = ! am\nt ( "w requir$1 !y 7 ext5d$ by t5ts & lean-to's1 or +5i\sly us$ z a nucleus = ! organization ( ! favor$ /able or cell>4 ,illu/ration3 ,,fig4 #aac4--,mobile photographic laboratory4 ,me?ods ( ,plate ,developm5t4--,:]e spe$ is n requir$ ! simple/ & commone/ mode ( develop+ plates is 9 ! tray1 "o plate at a "t4 ,common practice is to exam9e ! plate at int]vals dur+ developm5t1 & discont9ue ! op]ation on ! basis ( its appe>ance4 ,?is is only possible if ! plates us$ are ins5sitive to "s light by :i* ! eye c see4 ,deep r$ light is suitable = ord9>y & mo/ or?o*romatic plates4 ,a fa9t blue-gre5 may be us$ ) "s pan*romatic plates4 ,! be/ practice1 h[ev]1 is to develop by "t 9 total d>kness1 :]eby all *ance ( d>k room fog is avoid$4 ,developm5t "t = plates ( ! av]age exposure ( ! "o to be develop$ is ei!r kn[n f previ\s exp]i5ce1 or is f\nd by trial on ! fir/ "o4 ,developm5t by "t results 9 negatives ( d5sities v>y+ ) ! exposures1 b1 z 0 br\ght out 9 ! discussion ( s5sitometry1 ?is diff]5ce c be comp5sat$ = by ! *oice ( ! pap] us$ = pr9t+1 & by its treatm5t4 ,illu/ration3 ,,fig4 #aad4--;,int]ior ( photographic trail]1 develop+ room4 ,:]e l>g] quantities ( plates are to be h&l$ tank developm5t is adopt$4 ,9 ord9>y tank developm5t ! plates are plac$ 9 groov$ tanks1 into :i* is p\r$ fir/ ! develop]1 next ! r9s+ wat]1 & !n ! hypo4 ,x has be5 cu/om>y 9 tank developm5t z practic$ = peace-"t "w to use dilute develop]1 requir+ f t5 to ?irty m9utes1 b spe$ requirem5ts 9 w>-"t a]ial photography dictate ! use ( full-/r5g? quick-act+ develop]4 ,an improvem5t on ! simple groov$ tank is provid$ by metal cages or racks1 ea* hold+ a doz5 or m plates1 :i* may be introduc$ or remov$ f ! tank z a unit 7,fig4 #aaf74 ,illu/ration3 ,,fig4 #aae4--;,int]ior ( photographic trail]4 ,enl>g+ cam]a & pr9t]4 ,! core rack sy/em comb9es c]ta9 ( ! features ( bo? tray & tank developm5t4 ,ea* plate is ins]t$ 9 a sep>ate metal frame ) project+ lugs to re/ on ! top ( ! tank & s susp5d ! plate 9 ! solution4 ,! process ( developm5t is ! same z 9 ! tank sy/em1 b any individual plate may be exam9$ & remov$4 ,illu/ration3 ,,fig4 #aaf4--,tank & rack = tank developm5t4 ,film ,develop+ & ,fix+4--,! problem ( quickly h&l+ roll film ( l>ge size is "o ^u ^: solution dep5ds 9 l>ge degree ! feasibility ( film cam]as = a]ial "w4 ,x pres5ts _m difficulties3 a long film is unwieldy1 is inh]5tly subject to curl+1 & takes up mu* space if x is h&l$ entire4 ,= small scale op]ations roll film c be cut into %ort /rips & develop$ ei!r by draw+ ?r\gh a tray or1 if co/ ( develop] is no object1 9 a deep tank4 ,9 ord] to make ! cutt+ ap>t ( exposures easy 9 ! d>k1 film cam]as %\ld make "s =m ( pun* m>k 9 ! film betwe5 ! expos$ p>ts1 or ! space betwe5 exposures %\ld be uni=m1 s t a pr9t trimm] set to a def9ite m>k may be us$4 ,racks = hold+ two or ?ree feet ( film1 fold$ back on itself & clasp$ by spr+ clo!s-p9s1 are fairly practical4 ,"o object ( ! use ( film1 h[ev]1 is to greatly increase ! numb] ( possible exposures2 & :]e hundr$s in/ead ( doz5s ( exposures are to be develop$1 ?is me?od takes up entirely too mu* "t4 ,foll[+ ! practice 9 mov+ picture developm5t1 film develop+ ma*9es ( v>i\s designs h be5 devis$4 ,among ^! may be describ$ ! ,g4 ,e4 ,m4 ma*9e2 ! ,ansco ma*9e2 ! ,ea/man apron ma*9e2 ! ,brock frame & tank app>atus2 ! ,ea/man reel ma*9e2 & a modification ( ! latt] by ! ,unit$ ,/ates ,air ,s]vice4 ,! ,g4 ,e4 ,m4 film develop+ app>atus1 simil> 9 idea to ! ,ea/man 8apron0 me?od ( film develop+1 z exemplifi$ 9 ! famili> amateur film develop+ ma*9es1 has ! film w\nd 9 a spiral on a long l9k$ metal frame or *a94 ,aft] be+ w\nd x is plac$ 9 a tub ( develop]1 f t to a tub ( wat]1 !nce to a tub ( hypo1 & f9ally to a tub ( wat]1 :]e x is wa%$ 9 sev]al *anges4 ,! objections to ! me?od are t x takes up mu* floor space = ! v>i\s tubs1 & t x requires su* l>ge quantities ( solution4 ,to develop a ?irty-five foot l5g? ( #ah #bd c5timet] exposures requires approximately #bh gallons ( develop]2 = ! r9s+1 #bh gallons ( wat]1 & ! same = hypo1 & at lea/ ?ree times t = wa%+4 ,9 all #afh gallons ( wat] mu/ be br\ght to ! develop+ hut or lorry4 ,! ,ansco ma*9e makes use ( an idea frequ5tly appli$ 9 ! mov+ picture indu/ry4 ,! film is c>ri$ spirally1 ^u two cross-arms :i* bisect ea* o!r at "r angles1 & :i* conta9 v]tical p9s ar\nd :i* ! film is loop$1 beg9n+ at ! c5t] & work+ out4 ,aft] x is w\nd x is plac$ 9 a tub ( develop]1 z 9 ! ,g4 ,e4 ,m4 ma*9e4 ,x has an advantage ov] ?is app>atus 9 t ! %ape ( ! tubs or tanks is squ>e in/ead ( r\nd4 ,b x is equally extravagant ( space & wat]4 ,?is same criticism may be made ( ! ,ea/man apron app>atus = film develop+4 ,?is is simil> to ! ,g4 ,e4 ,m4 ma*9e1 b diff]s f x 9 us+ a p]=at$ celluloid apron to support ! film dur+ ! v>i\s op]ations1 in/ead ( a metal *a94 ,! ,brock develop+ outfit consi/s ( a rectangul> wood5 frame & a ?ree-comp>tm5t tank4 ,! frame1 :i* is approximately #c by #d feet 9 size1 is us$ z a support = ! #d in* wide film1 :i* is w\nd spirally ar\nd x1 betwe5 guid+ p9s4 ,a special support is provid$1 on :i* ! frame may be rotat$ z ! film is f$ (f ! cam]a spool4 ,! frame1 ) ! film on x1 is l[]$ successively into ! ?ree n>r[ b deep comp>tm5ts ( ! develop+ tank4 ,! fir/ comp>tm5t holds develop]1 ! next wat]1 ! next hypo4 ,! am\nt ( develop+ solution requir$ is r l>ge 7#if gallons ( wat] 9 all = a /rip ( #ajj #d #e in* exposures71 b because ( ! small surface expos$ to ! air1 x keeps = a consid]able p]iod4 ,! *ief dem& = floor space ) ?is app>atus is = fe$+ ! film on to ! frame4 ,9 ! ,ea/man tw9 reel ma*9e ! film is w\nd on a wood5 drum or reel ( l>ge diamet]1 to =m a helix4 ,! drum is susp5d$ s t ! bottom edge t\*es ! develop+ solution1 &1 ^u revolv+ ! drum1 e portion ( ! helix ( film is br\ght into contact ) ! develop]4 ,by %ap+ ! develop+ tank s t x closely con=ms to ! %ape ( ! reels1 a high economy 9 quantity ( develop+ ag5t c be a*iev$4 ,:5 develop+ action is f9i%$1 ! develop] is empti$ out1 r9se wat] put 92 hypo foll[s1 & !n comes ! f9al wa%+ ) wat]4 ,) ?is app>atus ! :ole cycle is complet$1 = ! #ce feet l5g? ( film above consid]$1 ) sev5 gallons ( wat]4 ,! ,air ,s]vice app>atus diff]s f ! above only 9 ! dry+ me?od1 :i* w be describ$ bel[4 ,heavy cut film1 su* z is m>ket$ "u ! "n ( ,portrait ,film1 has n ?us f> be5 us$ 9 a]ial "w1 except = pr9t+ transp>5cies4 ,x is conceivable1 h[ev]1 t film 9 ! cut =m may be us$ 9 "s future design ( cam]a4 ,?is may be develop$ exp$iti\sly 9 a tray1 six or eight films be+ h&l$ at a "t1 9 a pile1 pull+ out ! l[] "o frequ5tly & plac+ x on top4 ,! core rack sy/em is also available = film 9 ?is =m1 special racks ) clips to hold ! film be+ necess>y4 ,plate ,dry+4--,! dry+ ( negatives on glass is a comp>atively simple matt]1 ow+ to ! rigid nature ( ! emulsion support4 ,a l>ge numb] ( plates may be plac$ 9 a compact mass 9 ! ord9>y plate racks ( comm]ce ) ! wet sides accessible to a draft ( air4 ,two doz5 plates sep>at$ f ea* o!r by a qu>t] ( an in* & left to dry spontane\sly 9 a room ( ord9>y humidity & liv+ temp]ature w dry 9 two h\rs & a half4 ,if ! surface be wip$ ) s(t *eese-clo? or *amois1 s z to absorb all ! surface moi/ure be=e ! plates are plac$ on ! rack1 ?is "t may be appreciably r$uc$4 ,by plac+ ! plates 9 a =c$ draft ( air1 f an electric fan1 ?is "t may be r$uc$ to an h\r4 ,extra rapid dry+ ( plates may be accompli%$ by plac+ !m 9 a ba? ( alcohol be=e putt+ !m 9 ! racks4 ,! alcohol displaces all ! wat] 9 ! film1 & is itself v quickly dissipat$ into ! atmosph]e :5 ! plate is tak5 f ! tray4 ,! plate mu/ be left 9 ! alcohol tray long en\gh = ! sub/itution ( ! alcohol = ! wat] 9 ! film to take place4 ,five m9utes is long en\gh4 ,! alcohol be=e use mu/ be z ne>ly free f wat] z possible4 ,! be/ way to make sure ( ?is is to place 9 ! bottle ( alcohol "s lumps ( calcium oxide1 :i* w take up ! wat] & =m calcium hydroxide1 :i* settles at ! bottom ( ! bottle4 ,ano!r me?od ( quick plate dry+ takes advantage ( ! extraord9>y gre$9ess ( potassium c>bonate = wat]4 ,! wet plates are plac$ 9 a saturat$ solution ( potassium c>bonate & left = a m9ute4 ,if a plate be n[ tak5 f ! solution & its surface wip$ ) a s(t clo?1 x w be f\nd t ! film has a greasy1 slipp]y feel+1 b t x conta9s no wat] & c be pr9t$ f at once4 ,plates s treat$ %\ld be wa%$1 h[ev]1 at "s "t 9 ! succe$+ f\r mon?s1 or ! traces ( potassium c>bonate left 9 ! film cause det]ioration4 ,film ,dry+4--,unlike ! dry+ ( plates1 dry+ ( film negatives is a v puzzl+ problem1 & may be consid]$ z ! crux ( ! successful use ( film 9 a]ial cam]as4 ,apron & simil> ma*9es h v poor dry+ effici5cy if ! film is left 9 place1 = n only ! film b ! apron or *a9 mu/ be fre$ ( wat]4 ,?is may be ha/5$1 z 9 ! ,g4 ,e4 ,m4 ma*9e1 by bl[+ air ?r\gh ) fans1 b ev5 ) _! help dry+ a #ce foot film is a matt] ( two h\rs or m4 ,pass+ ! film ?r\gh wr+]s or a squeegee to remove excess wat] is a consid]able aid2 ! film may ei!r be re-w\nd on a dry reel1 to be put 9 a =c$ draft ( air1 or may be hung up 9 %ort l5g?s or fe/oon$1 ei!r me?od tak+ up a great deal ( space4 ,! use ( alcohol is n advisable z x may ab/ract camphor f ! celluloid & cause ! film to become di/ort$4 ,! ,ea/man tw9 reel ma*9e _h an upp] reel jo9$ to ! l[] or develop+ reel1 ) a *a9 & sprockets1 s t ! upp] reel revolv$ at ! same "t & rate ( revolution z ! l[]1 :5 ! l[] 0 be+ revolv$ at ! g5tle spe$ appropriate to ! develop+ process4 ,fans blew a draft ( air ov] ! upp] reel4 ,?is me?od necessitat$ ov] an h\r = dry+4 ,illu/ration3 ,,fig4 #aag4--,u4 ,s4 ,air ,s]vice film develop+ ma*9e = film #bd c5timet]s wide4 ,! ,air ,s]vice model ( film develop+ & dry+ ma*9e 7,fig4 #aag7 introduces an ess5tial modification 9 ! dry+ s*eme ( ! ,ea/man app>atus4 ,! upp] reel is q indep5d5t ( ! l[] reel & is revolv$ at a high rate ( spe$1 s t a :irl+ action is introduc$ into ! dry+4 ,l>ge rotat+ fans at ! same "t drive a consid]able volume ( air across ! film surface1 & ! comb9ation ( ! two ag5cies makes x possible to dry #ce feet ( #ah #bd c5timet] film 9 #bj to #cj m9utes4 ,?is = l>ge numb]s ( pictures makes ! use ( film ev5 quick] ?an t ( plates4 ,! only practical drawback to ! app>atus is its bulk1 :i* calls = a sep>ate room or trail]4 ,?is1 h[ev]1 seems to be inevitable 9 ! use ( l>ge roll film4 ,cut film c be dri$ ) spe$ only if plac$ 9 a draft ( w>m air4 ,dry+ boxes1 ) a *ute or *imney & ) fans to drive ! air ?r\gh f an alcohol /ove1 w dry sev]al doz5 films 9 an h\r4 ,! films mu/ n be clos] toge!r ?an ab\t "o in*1 :i* makes ! dry+ boxes r cumb]some4 ,m>k+ ,negatives4--,aft] developm5t & dry+1 & be=e fil+ or pr9t+1 ea* plate %\ld be m>k$ ) data = purposes ( future id5tification4 ,?is is mo/ easily done ) p5 & ink on ! film side 79 rev]s$ lett]+7 ei!r along an edge 9 ! unexpos$ portion cov]$ by ! %ea? or 9 a corn]1 s z to lose z little ( ! photograph z possible4 ,j :at data %all be inscrib$ is dictat$ by ! purpose = :i* ! negative 0 made4 ,! date1 altitude1 "t ( day1 true nor? 7f kn[n p]man5t features or f %ad[ direction & "t ( day71 numb] ( ! cam]a us$1 ! focal l5g? ( ! l5s4 ,o!r records1 su* z ! plane & squadron numb]s1 or ev5 ! pilot's & obs]v]'s initials1 may be call$ = 7,fig4 #ge74 ,= mapp+ "w ! scale ( ea* ( a set ( negatives1 once f\nd1 may be m>k$1 ei!r 9 figures or by means ( a l9e ( l5g? correspond+ to a fix$ di/ance on ! gr\nd4 ,rectify+ data c simil>ly be inscrib$1 s t ! negative c be pr9t$ 9 ! enl>g+ & rectify+ cam]a ) ! m9imum ( delay4 ,,*apt] ,,xxiv ,,pr9t+ ,,& ,,enl>g+ ,contact ,pr9t+4--,s+le pr9ts are made mo/ simply 9 a pr9t+ frame held at a %ort di/ance f a light s\rce4 ,:5 any quantity mu/ be made1 z 9 turn+ out pr9ts at high spe$ = di/ribution to an army be=e an attack1 pr9t+ ma*9es are employ$4 ,^! consi/ ess5tially ( a light box1 a pr9t+ frame ( plate glass1 & a pressure pad4 ,9 ! comm]cial models1 su* z ! ,cr[n & ! ,ansco1 :i* are equipp$ ) electric light1 m]ely br++ ! pressure pad d[n & clamp+ x automatically turns on ! light1 :ile release ( pressure t]m9ates ! exposure4 ,! "q ( regulat+ ! di/ribution ( light is ( consid]able importance ) negatives tak5 by focal-plane %utt]s ( non-uni=m rate ( travel4 ,9 ! ,mc,intire pr9t] 7,fig4 #aai71 ! sep>ate electric bulbs are on long necks 9 ball & socket jo9ts1 s t !y c be br\ght individually clos] to ! pr9t+ surface or f>!r away f x1 ?us p]mitt+ a wide range ( 8dodg+40 ,?is pr9t] also has an automatic "t control = ! light1 a valuable device :]e _m pr9ts f ! same negative are desir$4 ,^! ma*9es are well suit$ = pr9t+ a]ial negatives1 ei!r plate or cut film1 if us$ :]e a s\rce ( electric curr5t is available4 ,! *ief defect1 :i* may be caus$ by faulty con/ruction1 is imp]fect contact betwe5 pap] & negative1 a cause ( s]i\s un%>pness on pr9ts de/9$ = m9ute /udy 9 int]pretation4 ,illu/ration3 ,,fig4 #aah4--,pr9t+ ma*9e4 ,! pr9t+ ( a]ial negatives may be done ei!r on roll or cut pap]1 & if films are us$1 a fur!r alt]native is (f]$ ( h&l+ x ei!r 9 ! roll or 9 cut =m4 ,:]e _m pr9ts are to be made f "o negative roll pap] has "s advantages1 p>ticul>ly if a develop+ & dry+ ma*9e is available4 ,b = mod]ate numb]s ! advantage is small1 s9ce cut pr9ts c be develop$ q conv5i5tly 9 goodly numb]s 9 ! ord9>y trays4 ,b ! advantages ( keep+ film 9 ! roll =m are v great1 bo? 9 respect to /orage & 9 respect to h&l+ dur+ pr9t+1 z ! roll]s provide ! necess>y t5sion & prev5t ! film 8gett+ away40 ,illu/ration3 ,,fig4 #aai4--;,int]ior ( ,mc,intire pr9t]1 %[+ lamps adju/able 9 position = 8dodg+40 ,illu/ration3 ,,fig4 #abj4--;,film pr9t+ ma*9e4 ,= ! ,am]ican ,air ,s]vice1 cut pap] has be5 us$ exclusively4 ,= film pr9t+1 ! ,ansco ma*9e has be5 equipp$ ) roll pivots to take film #bd c5timet]s wide :i* may be advanc$ 9 ei!r direction by turn+ l>ge mill$ heads 7,fig4 #abj74 ,if we put roll]s on ! two rema9+ sides ( ! box to h&le pap] we trans=m ! pr9t] into ! same =m z a ,fr5* ma*9e1 9 :i* pap] & film are mov$ at "r angles to ea* o!r4 ,a disadvantage ( ?is modification1 h[ev]1 is ! difficulty ( exam9+ ! negative to be pr9t$4 ,/]eo ,pr9t+4--,to make sep>ate pr9ts f ! two elem5ts ( a /]eoscopic pair & m\nt !m side by side aft] prop] ori5tation is too sl[ a process if quantities ( pr9ts are ne$$4 ,"o me?od ( multiple production is to make a ma/] /]eogram1 & !n produce photographic copies ( x1 b !re is inevitable loss ( quality 9 ?is copy+ process4 ,an int]m$iate me?od is to pr9t f bo? negatives on ! same %eet ( pap]4 ,9 ord] to d ?is ! negatives mu/ be plac$ 9 r l>ge frames1 ) mats prop]ly locat$ to guide ! plac+ ( ! pap]4 ,! ,ri*>d d\ble pr9t+ frame is a practical device :i* simplifies ! necess>y manipulations4 ,x consi/s ess5tially ( a plat=m pi]c$ ) ?ree illum9at$ op5+s4 ,! two negatives are comp>$1 sup]pos$1 & ori5tat$ ov] ! c5tral op5+ & !n %ift$ lat]ally1 "o to ea* ( ! two side op5+s1 :i* s]ve bo? z pr9t+ frames & masks4 ,! pr9t+ back slides on a rod1 p]mitt+ ! pap] to be lift$ up & mov$ betwe5 exposures4 ,once ! negatives are prop]ly plac$1 /]eo pr9ts c be turn$ out quickly & easily4 ,enl>g+4--,9 ! ,fr5* s]vice contact pr9t+ 0 ! rule dur+ ! w>4 ,! ,engli% practice1 on ! o!r h&1 0 to take small negatives--#d #e in*es1 ) #h to #ab in* l5ses--& enl>ge !m1 usually to #f #h in*es4 ,= ?is purpose a regul> "p ( ! ,engli% photo section equipm5t 0 ! enl>g+ cam]a 7,fig4 #aae74 ,?is may be briefly describ$ z a %ort focus cam]a 9 :i* ! subject to be photograph$ is a negative1 illum9at$ by transmitt$ light1 ^: image is ?r[n by ! cam]a l5s on ! pap] or o!r s5sitive surface4 ,by mak+ ! di/ance betwe5 negative & l5s less ?an t betwe5 l5s & pap]1 ! result+ pr9t is an enl>gem5t1 & vice v]sa4 ,! scale ( enl>gem5t or ( r$uction is v>i$ ov] limits set only by ! l5g? ( ! cam]a & ! am\nt ( light available4 ,! l5s employ$ mu/ ( c\rse possess suffici5tly high quality to pres]ve all ! %>pness ( ! negative1 & focuss+ mu/ be done ) accuracy4 ,next to ! l5s ! mo/ important elem5t is ! light s\rce4 ,?is may be ( ! po9t =m1 su* z a conc5trat$ filam5t electric lamp1 an oxy-acetyl5e lime light1 or an acetyl5e flame4 ,! latt] 0 ext5sively us$ 9 ! ,engli% s]vice1 :ile acetyl5e g5]ators = em]g5cy purposes =m$ "p ( ea* ,am]ican photo truck equipm5t4 ,) po9t light s\rces we mu/ use cond5s]s to focus ! light into ! project+ l5s4 ,mu* less effici5t1 b ! only rec\rse :]e l>ge cond5s]s are n available1 is a diffus+ glass beh9d ! negative1 illum9at$ ei!r by a bank ( electric lamps ) mirrors or by a ,u tube m]cury vapor lamp1 :]e prop] curr5t c be got4 ,! device = hold+ ! pr9t+ pap] mu/ p]mit quick *ang+1 b insure good contact4 ,we may use ei!r a spr+ plate to hold ! pap] aga9/ plate glass f beh9d1 or else a weight act+ on a lev] arm ( suffici5t l5g?4 ,! ne$ = "s automatic means ( focuss+ an enl>g+ cam]a has be5 v g5]ally felt4 ,an illu/ration ( su* an enl>g+ cam]a is t put out by ,williams1 ,br[n ,e>le1 ( ,philadelphia1 kn[n z ! 8,semp]focal0 7,fig4 #aba74 ,9 ?is cam]a ! movem5ts ( ! l5s1 pap] easel & negative are s int]-relat$ & actuat$ ) respect to ea* o!r t ! correct focus ( ! in/rum5t is ma9ta9$ = any degree ( enl>gem5t or r$uction4 ,?is feature is a great help 9 mak+ up mosaic maps1 :]e pr9ts ( cont9u\sly v>y+ scale ord9>ily occasion s]i\s delay = individual focuss+4 ,illu/ration3 ,,fig4 #aba4--8,semp]focal0 enl>g+ cam]a1 ) me*anism = hold+ image 9 focus at any enl>gem5t4 ,det]m9+ ! correct enl>gem5t = ea* negative ( a mosaic is p]haps ! mo/ important problem 9 ! use ( ! enl>g+ cam]a = a]ial "w4 ,! correct sett+ ( ! cam]a may be f\nd by ei!r ( two me?ods3 ! negative may be previ\sly scal$ & m>k$ ) a l9e on its edge1 :i* mu/ be project$ to a def9ite size2 or ! true location ( sev]al po9ts 9 ! picture z obta9$ f an accurate map may be m>k$ on ! enl>g+ cam]a easel accord+ to ! desir$ scale1 & ! negative image project$ to co9cide ) ^!4 ,9 ei!r case1 if an exact scale is desir$1 all[ance mu/ be made = pap] %r9kage1 a matt] :i* mu/ be det]m9$ by previ\s exp]im5t4 ,rectify+4--,negatives tak5 :5 ! plane is n fly+ level w be di/ort$ 7,figs4 #acd & #ace74 ,contact pr9ts f ^! w n fit into a mosaic1 & no m]e enl>gem5t or r$uction w make !m available4 ,x is necess>y ) ^! negatives to resort to a rectify+ cam]a4 ,?is is an enl>g+ cam]a built s t ! negative & pr9t easel may be incl9$ ab\t v]tical & horizontal axes1 !reby purposely introduc+ a di/ortion suffici5t to (fset ! di/ortion ( ! negative4 ,?us1 if ! bottom ( ! pr9t+ surface is mov$ away f ! l5s1 t "p ( ! picture w be enl>g$2 if mov$ t[>d ! l5s1 r$uc$4 ,= small rectifications ! common practice is to tilt ! pr9t+ surface alone1 a me?od t is practical z long z ?is tilt+ does n affect ! focus s mu* z to require prohibitive /opp+ d[n ( ! l5s4 ,= great di/ortions1 su* z t inh]5t 9 ! pr9ciple ( ! ,bagley cam]a1 x is necess>y to tilt bo? negative & pr9t 9 ord] to pres]ve an approximate focus1 a giv5 portion ( ! negative mov+ t[>d ! l5s z ! correspond+ portion ( ! pr9t is mov$ away4 ,bo? s*emes = rectification are %[n diagrammatically 9 ,fig4 #abb4 ,develop+ & ,dry+ ,pr9ts4--,! develop+ ( pr9ts foll[s closely t ( cut or roll film1 & s ne$ n be treat$ sep>ately4 ,! dry+ ( emulsions on pap] is m easily accompli%$ ?an ! dry+ ( emulsions on glass1 = two reasons3 ! emulsions on pap] are mu* m ?9ly coat$1 & !re is diffusion ( moi/ure into ! atmosph]e f front & back ( ! pr9t+ m$ium4 ,9 ! field a common me?od has be5 to soak ! pr9ts 9 wat]-free alcohol & !n burn (f ! alcohol1 ?us secur+ a dry pr9t )9 two or ?ree m9utes aft] ! conclusion ( wa%+4 ,a lat] me?od v g5]ally employ$ is to cov] wood5 frames ?ree or f\r feet above ! gr\nd ) *ick5 wire or musl91 & on ^! lay ! pr9ts aft] soak+ !m 9 alcohol4 ,bel[ ! frames curr5ts ( w>m air rise f pans ( burn+ alcohol1 previ\sly us$ to soak ! pr9ts & n[ useless z alcohol because ( _! high wat] cont5t4 ,illu/ration3 ,,fig4 #abb4--;,diagram %[+ enl>g+ ) & )\t di/ortion3 ,a1 enl>g+ )\t di/ortion2 ,b1 di/ortion = rectification ( pr9t1 by incl9+ pr9t+ surface2 ,c1 di/ortion1 = rectification ( pr9t1 by incl9+ bo? negative & pr9t+ surface4 ,be=e putt+ !m 9 alcohol x is advisable to squeegee all ! surface wat] f ! pr9ts4 ,?is may be exp$iti\sly done by remov+ !m 9 mass f ! f9al wa% wat] ^u a l>ge f]rotype plate1 & ei!r runn+ ! plate & pr9ts toge!r ?r\gh a wa% wr+] ) light pressure1 or cov]+ ! :ole ) a %eet ( blott+ pap] & press+ out ! wat] und]nea? by means ( a rubb] squeegee vigor\sly appli$4 ,= base "w "o ( ! mod]n automatic pr9t-dry+ ma*9es us$ 9 comm]cial photography w\ld be desirable4 ,glossy surfaces are giv5 pr9ts by ! usual f]rotype plate me?od4 ,b ?is is too "t-consum+ = w> practice1 & besides has b d\btful advantage :]e pap]s ( ! glossy type are *os54 ,,vi ,,practical ,,problems ,,& ,,data ,,*apt] ,,xxv ,,spott+ 8,spott+10 z di/9ct f mapp+ or f ! photography ( cont9u\s /rips1 is ! photography ( a def9ite individual objective4 ,9 milit>y "w spott+ or 8p9 po9t+0 includes ! photography ( p>ticul> tr5*es or pivotal po9ts 9 a tr5* sy/em be=e an attack 7,fig4 #abc71 ( roads or bridges along :i* an advance mu/ pass 7,fig4 #abd71 ( batt]ies or big guns :i* are ! subject ( artill]y fire 7,fig4 #abe71 bo? be=e & aft] _! bomb>dm5t 7,fig4 #abf71 ( gun puffs or explod+ bombs 7,fig4 #aca74 ,! te*nique ( spott+ consi/s l>gely 9 gett+ prop]ly ov] ! t>get & !n secur+ ! exposure at j ! "r mom5t4 ,?is is *iefly a "q ( prop] pilot+2 b ! aid :i* c be (f]$ to ! pilot by cam]a auxili>ies design$ p>ticul>ly = spott+ ne$s is v l>ge4 ,discussion ( ! task ( ! pilot :o mu/ /e] a photographic plane accurately ov] a previ\sly select$ po9t ( int]e/ _c be und]tak5 )\t rais+ ! "q ( :o %\ld take ! picture1 pilot or obs]v]8 ,9 ! ,engli% s]vice ! mo/ g5]al practice 0 = ! pilot to be *>g$ ) ! responsibility bo? ( cov]+ ! objective & ( expos+4 ,if a propell] drive 0 us$ on ! cam]a1 ?is left to ! obs]v] only ! task ( *ang+ magaz9es4 ,if ! cam]a 0 h& op]at$ ! plates 7 *ang$ ei!r by ! obs]v]1 or else1 z 0 frequ5tly ! case1 di/ance op]at+ devices 7 atta*$1 s t ! pilot ev5 !n did ev]y?+ except *ange ! magaz9es1 & ! obs]v] 0 kept free to wat* ! sky = enemy aircraft4 ,a v desirable adjunct to ! cam]a :5 plates are %ift$ automatically or by ! obs]v] is a di/ance indicator1 to %[ ! pilot :5 ! %utt] is set4 ,electrical indicators = ?is purpose h be5 devis$4 ,illu/ration3 ,,fig4 #abc4--,l[ view ( tr5*es on ! ,ys]1 %[+ concrete /ructures undamag$ by bomb>dm5t4 ,illu/ration3 ,,fig4 #abd4--,! ,piave ,riv]4 ,to left1 de/roy$ bridge1 to "r1 pontoon bridge "u con/ruction4 ,italian a]ial photographic s]vice4 ,illu/ration3 ,,fig4 #abe4--,%[+ big gun hidd5 9 =e/4 7,upp] left-h& corn]74 ,illu/ration3 ,,fig4 #abf4--;,example ( spott+4 ,batt]y be=e & aft] bomb>dm5t4 ,if ! cam]a is completely h& op]at$1 z 7 mo/ ( ^? 9 ! ,fr5* & ,g]man s]vices1 !re is little *oice b = ! obs]v] to p]=m ! entire op]ation4 ,! expos+ op]ation c\ld h be5 delegat$ to ! pilot1 b su* 0 n ! cu/om ) ! ,fr5* or ) ! ,am]ican squadrons us+ ,fr5* app>atus4 ,9 ?is me?od ( op]ation ! obs]v] dep5ds on ! pilot to get ! plane ov] ! t>get1 :ile ! pilot dep5ds on ! obs]v] to get ! picture :5 ! t>get is cov]$4 ,ample opportunity is ?us (f]$ = misund]/&+ & disagreem5t4 ,?is c be avoid$ only by excell5t sights prop]ly align$1 = bo? pilot & obs]v]1 & by "s means ( communication betwe5 ! two m5 conc]n$4 ,illu/ration3 ,,fig4 #abg4--,photograph1 made ) long focus l5s to det]m9e ! results ( a]ial bomb+4 ,! 8,tirpitz0 batt]y ( long range naval guns direct$ on ,dunkirk4 ,! simple/ means ( communication is ( c\rse direct conv]sation4 ,b ?is is only possible 9 ^? planes1 su* z ! ,,dh-#i1 9 :i* pilot's & obs]v]'s cockpits are imm$iately toge!r1 s t1 by %\t+1 any desir$ in=mation c be convey$ ) fair ease4 ,:5 ! di/ance is increas$ to f\r or five feet1 z 9 ! ,,dh #d1 ! l\de/ %\ts are totally lo/ 9 ! ro> ( ! eng9e & ! bla/ ( ! w9d4 ,speak+ tubes & telephones are n[ fairly good1 b are none too com=table or conv5i5t to h /rapp$ on "o's head & face4 ,a primitive device us$ to "s ext5t 9 ! w> 0 m]ely a pair ( re9s atta*$ to ! pilot's arms1 by :i* he c\ld be direct$ :i* way to /e]4 ,!re is mu* to be said = a simple semaphore sy/em1 :]e an indicator 9 ! obs]v]'s cockpit actuates a simil> dial 9 front ( ! pilot1 indicat+ 8"r0 or 8left10 8picture obta9$10 8try aga910 etc4 ,if ! obs]v] has a sight by :i* he c see f> en\gh ahead to correct ! pilot's error ( po9t+1 ! ne$ = an accurate sight = ! pilot is dim9i%$4 ,illu/ration3 ,,fig4 #abh4--;,diagram %[+ relation%ip betwe5 focal l5g? & area cov]$ by plate4 ,illu/ration3 ,,fig4 #abi4--;,diagram giv+ data on area cov]$ at v>i\s altitudes by repres5tative l5s4 ,illu/ration3 ,,fig4 #acj4--;,bur*all ,slide ,rule1 = calculat+ int]vals betwe5 exposures1 & = o!r a]ial photographic data4 ,9 consid]+ ! "q ( sights1 att5tion may aga9 be call$ to ! poor 8visibility0 f ! pilot's seat 9 ! pres5t prevail+ type ( two-seat] tractor plane4 ,bl9d directly 9 front1 b5ea?1 & to ei!r side 7,figs4 #g1 #h & #i71 x is no unusual ?+ = a pilot to entirely miss an objective1 su* z a railway l9e1 :i* he c only e/imate to be b5ea? him by judg+ its di/ance f ^? objects to ei!r side :i* he c actually see4 ,! ,engli% practice ( leav+ a cle> space ( six in*es to a foot betwe5 ! fuselage & ! beg9n+ ( ! w+ fabric1 all[s ! pilot to look d[n ov] ! side1 a decid$ advantage4 ,b = photographic purposes no?+ c comp>e ) a good negative l5s c>ry+ =e & aft l9es or wires1 s t ! pilot c see 8 objective 9 ample "t to head directly = x4 ,! l5s %\ld ei!r be l>ge en\gh s t its re> edge gives ! view directly d[nw>d1 or supplem5t$ by an additional l5s po9t+ directly d[n1 s t ! cov]+ ( ! t>get is assur$4 ,to locate su* a l5s 9 ! front cockpit1 free ( all controls1 is a v h>d task2 ev5 s its view is likely to be badly int]rupt$ by ! l&+ ge>4 ,nev]!less1 s important is x1 bo? 9 photography & 9 bomb+1 to h a sight by :i* ! plane c be accurately direct$ t design]s ( planes %\ld recognize ?is ne$ & make e ef=t to provide a suitable location4 ,illu/ration3 ,,fig4 #aca4--;,a]ial bomb>dm5t ( ,trie/e4 ,note fall+ bombs 9 c5t] ( picture2 & explod+ anti-aircraft %ells ov] ! wat]4 ,italian (ficial photograph4 ,illu/ration3 ,,fig4 #acb4--;,example ( spott+ requir+ exposure at exact in/ant4 ,explosion foll[+ bur/ ( bomb 9 ammunition dump4 ,briti% (ficial photograph4 ,sights = ! obs]v] h be5 discuss$ already4 ,"h aga9 ! negative l5s is to be pref]r$1 b :ile ! pilot's l5s ne$s only direct+ l9es 9 ! axis ( ! plane 7unless he takes ! picture71 ! obs]v]'s l5s ne$s bo? an accurate c5t] m>k & an additional upp] or l[] sight+ po9t4 ,accurate alignm5t ( ^! m>ks ) ! cam]a axis mu/ be arrang$ = 9 precise spott+4 ,accurate spott+ "w requir+ ! del9eation ( f9e detail calls = cam]as ( consid]able focal l5g?4 ,! cam]a ( longe/ focal l5g? us$ 9 ! w> 0 ! ,fr5* #abj c5timet] 7,fig4 #da74 ,?is 0 employ$ ) great success 9 su* "w z regulat+ ! fire ( heavy railway guns br\ght into range only at night1 to fire a few %ots at *os5 angles4 ,photographs tak5 ! next day w\ld !n %[ ! exact spot :]e ea* %ell fell1 & ! damage x did1 to s]ve z a guide = ! next night's op]ations 7,fig4 #abg74 ,! field ( ^! cam]as is q small--#h to #ab degrees--& s n only mu/ sight+ be exact b ! area cov]$ on ! gr\nd mu/ be accurately kn[n4 ,?is is to be calculat$ f ! altitude1 focal l5g?1 & plate size1 by ! relation-- di/ance on gr\nd altitude ------------------------------------ ------------------------ plate l5g? focal l5g? ,data d]iv$ f su* calculations may be incorporat$ 9 tables1 or graphically 9 diagrams su* z ,figs4 #abh & #abi4 ,illu/ration3 ,,fig4 #acc4--,! same subject a few m9utes lat]4 ,height ( smoke %[n by %ad[4 ,briti% (ficial photograph4 ,^! calculations & o!rs requir$ 9 mapp+ & /]eo-"w are simply & quickly made by slide-rule devices4 ,"o ( ^!1 ! ,bur*ell ,photographic ,slide ,rule1 develop$ 9 ! ,engli% s]vice1 is %[n 9 ,fig4 #acj4 ,?is consi/s ( two dials1 ! c5t] "o ( :i* is m\nt$--usually by a p9 pu%$ into a cork beh9d--s z to turn freely1 to p]mit its be+ set = altitude1 focal l5g?1 gr\nd spe$1 plate size1 etc41 :]eupon ! area cov]$1 or ! appropriate int]val betwe5 exposures may be read (f4 ,cam]as = spott+ "w %\ld be capable ( exposure at ! exact mom5t desir$4 ,= if ! cam]a is ev] to cat* ! gun z x dis*>ges1 ! bomb z x falls 7,fig4 #aca71 or ! %ell z x explodes 7,fig4 #acb71 ! photograph mu/ be tak5 )9 ! in/ant4 ,automatic cam]as1 expos+ at regul> int]vals1 :ile adequate = mapp+1 are n fitt$ = _m k9ds ( spott+4 ,,*apt] ,,xxvi ,,map ,,mak+ ,te*nique ( ,negative ,mak+4--,/at$ 9 its simple/ t]ms1 ! :ole problem ( mak+ a photographic map f ! air consi/s 9 tak+ a l>ge numb] ( slightly ov]lapp+ negatives1 all f ! same altitude1 ) ! plane fly+ uni=mly level4 ,:5 trimm$ & m\nt$ 9 juxtaposition1 or pa/$ toge!r s z to ov]lap 9 _! common portions1 ! pr9ts f ^! negatives con/itute a complete pictorial map4 ,!re is ?us furni%$ by a few h\rs' labor topographic in=mation :i* w\ld be ! "w ( mon?s to obta9 by o!r means4 ,! mak+ ( map photographs involves all ! special te*nique ( spott+1 ) mu* 9 addition4 ,! pilot's task is n m]ely to g ov] "o object2 he mu/ navigate a n>r[ pa?1 at a con/ant altitude1 on an ev5 keel4 ,if he is to make n m]ely a ribbon1 b a map ( consid]able wid?1 he mu/ take successive trips p>allel to ! fir/1 ea* displac$ j f> en\gh f ! previ\s c\rse to insure t no portion is miss$--a difficult task inde$4 ,x is ! obs]v]'s duty to s "t ! int]vals betwe5 exposures t !y ov]lap en\gh1 b n s mu* z to be wa/eful ( plates or film4 ,he mu/ also *ange magaz9es or films s quickly z to miss no t]ritory1 or if "s be miss$1 8 is ! task ( direct+ ! pilot back to ! po9t ( ! la/ exposure1 :]e !y beg9 a new s]ies4 ,level fly+ is entirely a pilot's problem4 ,its importance w be realiz$ :5 we consid] ! accompany+ diagrams 7,figs4 #acd & #ace71 :]e ! effect on ! resultant picture is %[n ( climb+1 glid+1 or bank+ to ei!r side4 ,pr9ts f negatives di/ort$ 9 ?is way nei!r w be true repres5tations ( ! t]ritory photograph$1 nor w !y mat* :5 juxtapos$4 ,9 fact1 !y c be utiliz$ only if special rectify+ app>atus is available = pr9t+4 ,fly+ at a con/ant altitude is simil>ly necess>y if ! pr9ts are to be utiliz$ )\t enl>gem5t or r$uction 9 ord] to make !m fit4 ,illu/ration3 ,,fig4 #acd4--;,diagram %[+ effect ( bank+ on a]ial photograph4 ,illu/ration3 ,,fig4 #ace4--;,diagram %[+ effect ( climb+ & div+ on a]ial photograph4 ,assum+ a skill$ pilot :o w d 8 "p1 ! next /ep is to calculate ! exposure int]vals 9 ord] to insure an adequate ov]lap4 ,if a negative l5s is in/all$ :i* has be5 m>k$ ) a rectangle ! size ( ! cam]a field1 ! simple/ me?od is to e/imate ! prop] in/ant = exposure by wat*+ ! progress ( objects across ! l5s face4 ,?is ( c\rse requires con/ant att5tion1 & x is easi] to d ?is only occasionally1 9 ord] to det]m9e ! gr\nd spe$ 9 t]ms ( cam]a fields trav]s$ p] m9ute4 ,!reaft] exposures are to be made by "t1 z det]m9$ by a wat* or clock4 ,any desir$ degree ( ov]lap c be *os51 & ei!r e/imat$1 or m or less accurately fix$ by l9es m>k$ on ! negative l5s at a %ort] di/ance ap>t ?an ! edges ( ! field4 ,! mo/ usual ov]lap is #bj p] c5t41 except = /]eos1 :i* call = #ej to #ge p] c5t4 ,9 ! abs5ce ( a negative l5s or "s o!r sight to %[ ! :ole cam]a field1 x is necess>y to resort to calculation f ! spe$ & altitude ( ! plane1 ! focus ( ! l5s & ! dim5sions ( ! plate4 ,if ,a is ! altitude1 a ! focal l5g? ( ! l5s1 d ! diamet] ( ! plate 9 ! direction ( travel 7usually ! %ort l5g? is *os5 = economy ( flights to cov] a giv5 wid?71 f ! fractional "p by :i* "o negative is desir$ to ov]lap ! next1 & ,v ! gr\nd spe$ ( ! plane1 !n we h1 by simple proportion1 t ! int]val betwe5 exposures1 t1 mu/ be-- ,ad7#a - f7 t -------------------------- a,v ,if ,a #bjjj met]s1 d #ah c5timet]s1 f 1 a #ej c5timet]s1 & ,v #bjj kilomet]s p] h\r1 ?is relation gives-- #bjjj 4#ah 4#h #cfjj t ---------------------------------------- ---- #aj4c seconds 4#e #bjj1jjj ,! pr9ciple ( ov]lapp+ map exposures is %[n 9 ! accompany+ diagram 7,fig4 #abi71 toge!r ) data calculat$ z above = a #d #e in* plate4 ,x is p>ticul>ly to be not$ t x is ! gr\nd spe$ ( ! plane t is us$4 ,?is may be calculat$ by kn[+ ! air spe$ & ! w9d velocity & direction4 ,fig4 #acf %[s ! me?od ( do+ ?is graphically4 ,fir/ an arr[ is drawn repres5t+ ! direction x is desir$ to fly4 ,next a second arr[ is drawn ( l5g? to repres5t ! w9d velocity4 ,?is mu/ be incl9$ t[>d ! fir/ arr[ 9 ! direction ( ! w9d1 & its head is to t\* ! head ( ! fir/ arr[4 ,!n ) ! f>!r end ( ?is second arr[ z a c5t]1 describe a circle ( su* a l5g? z to repres5t ! air spe$ ( ! plane1 9 ! same units z ! w9d velocity4 ,connect ! po9t :]e ?is circle cuts ! arr[ ( flight direction to ! c5t] ( ! circle by a /raight l9e4 ,?is l9e con/itutes ! air spe$ arr[1 giv+ ! direction x is necess>y to fly1 at ! giv5 air spe$1 to make ! c\rse desir$4 ,! l5g? ( ! flight direction arr[ betwe5 its head & its po9t ( int]section ) ! air spe$ arr[ gives ! gr\nd spe$4 ,illu/ration3 ,,fig4 #acf4--;,diagram %[+ me?od ( calculat+ gr\nd spe$ f air spe$ & w9d velocity4 ,:5 ! w9d is ahead or a/]n ?is calculation r$uces to ! simple subtraction or addition ( ! w9d velocity to ! air spe$ ( ! plane4 ,:5ev] possible1 mapp+ %\ld be done up & d[n ! w9d 7,fig4 #acg74 ,if ! plane is 8crabb+10 ! above calculations = ov]lap are only valid if ! cam]a c be turn$ normal to ! direction ( travel ov] ! gr\nd4 ,if ! cam]a _c be s turn$ ! corn]s ( ! successive pictures ov]lap in/ead ( _! sides1 ) q unsatisfactory results 7,fig4 #ach74 ,calculation ( ! di/ance ap>t ( ! p>allel flights necess>y to make a map ( any wid? is done by ! use ( a =mula simil> to ! longitud9al ov]lap =mula above1 di/ance figur+ in/ead ( "t4 ,us+ ! same symbols1 & d5ot+ ! di/ance by ,d1 we h-- ,ad7#a - f7 ,d -------------------------- a ,) ! same figures z be=e1 b sub/itut+ #bd c5timet]s = ! plate dim5sion1 ?is relation gives-- #bjjj 4#bd 4#h ,d ------------------------------ #gfh met]s 4#e ,illu/ration3 ,,fig4 #acg4--,ov]laps made :5 fly+ ) or aga9/ ! w9d4 ,illu/ration3 ,,fig4 #ach4--,unsatisfactory ov]laps made :5 plane is 8crabb+40 ,x is ( c\rse l>gely a pilot's problem to /e] ! plane ov] p>allel c\rses at a giv5 di/ance ap>t1 al?\gh ! obs]v]1 not+ conspicu\s objects ?r\gh a prop]ly m>k$ negative l5s1 may direct ! pilot by any ( ! means ( communication already m5tion$4 ,an alt]native me?od ( secur+ p>allel /rips1 :i* is to be highly recomm5d$ :]e en\gh photographically equipp$ airplanes are available1 is = sev]al planes to fly side by side1 ma9ta9+ _! prop] sep>ation 7,fig4 #aci74 ,cam]as & ,auxili>ies = ,map ,mak+4--,mapp+ c be done q satisfactorily by h& op]at$ or semi-automatic cam]as1 provid$ ! obs]v] has n too _m o!r duties4 ,on ! o!r h&1 ! op]ation ( expos+ at m or less def9ite int]vals ( "t1 irrespective ( ! object imm$iately pres5t$ to ! cam]a1 is a l>gely me*anical "o4 ,x naturally sugge/s ! employm5t ( an automatic me*anism1 ^: spe$ ( op]ation only is x necess>y to wat*4 ,if a non-automatic cam]a is us$ ! tim+ ( exposures may be done by wat*+ a negative l5s1 z describ$ above1 or by ref]5ce to a clock1 assum+ t ! gr\nd spe$ is kn[n ?r\gh calculation4 ,a v practical advance ov] ! ord9>y use ( a clock is to atta* a /op-wat* to ! %utt] release1 s t x is turn$ back to z]o & re-/>t$ at ea* exposure 7,fig4 #gj74 ,9 pass+1 x may be not$ t if ! /op-wat* h& makes an electric contact :i* ?r[s ! %utt] release1 !n ! device con/itutes an atta*m5t = turn+ any semi-automatic cam]a into an automatic4 ,! mo/ suitable cam]as = mapp+ are unque/ionably ^? ( ! entirely automatic type4 ,! use ( su* cam]as always dem&s a k ( ! gr\nd spe$4 ,?is dem& has l$ to _m sugge/ions = gr\nd spe$ indicators4 ,! common idea ( ^! is to provide a mov+ "p on ! plane--ei!r a disc ( l>ge diamet]1 or a *a91 or a revolv+ screw--^: spe$ may be v>i$ until any po9t ^u x appe>s to keep 9 co9cid5ce ) a po9t on ! mov+ l&scape bel[4 ,! gr\nd spe$ is !n to be read (f a prop]ly calibrat$ dial4 ,or1 z a fur!r /ep1 ! frequ5cy ( ! exposures may be directly controll$ by ! gr\nd spe$ indicator me*anism4 ,! entire control ( ! cam]a w\ld !n consi/ m]ely 9 occasional adju/m5t ( ! gr\nd spe$ indicator4 ,illu/ration3 ,,fig4 #aci4--,planes />t+ out to make a map by fly+ 9 p>allel4 ,:ile entirely possible 9 !ory1 ^! devices are n easy to "w ) 9 practice1 because ! plane is always subject to "s pit*+ & roll+1 :i* make x difficult to hold any object con/antly on ! mov+ po9t4 ,?is is especially true at high altitudes1 :]e ! app>5t motion ( ! e>? is q sl[ comp>$ to ! sw]v+s ( ! plane4 ,?is objection is 9 "p remov$ if ! gr\nd spe$ indicator is c>ri$ by a gyro /abiliz]4 ,ord9>y mapp+ does n dem& su* exquisite r5d]+ ( detail z does tr5* mapp+4 ,nor is x necess>y to fly 9 peace-"t at su* high altitudes z 9 w>4 ,9 consequ5ce1 mapp+ cam]as are pref]ably ( ! %ort focus1 wide angle type1 say1 #be c5timet] focus = an #ah #bd c5timet] plate4 ,film is to be pref]r$ ov] plates because ( ! great] numb] ( exposures x is possible to make on a flight4 ,! %utt] ( ! mapp+ cam]a mu/ be extremely uni=m 9 its rate ( travel s t ! elem5ts ( ! map may mat* 9 tone 7,fig4 #adj74 ,a m\nt :i* p]mits ! cam]a to be turn$ normal to ! direction ( flight1 su* z ! ,briti% turret m\nt 7,fig4 #hg71 is p>ticul>ly desirable if fly+ across ! w9d is necess>y1 z w (t5 be ! case 9 mapp+ /rips betwe5 t[ns or betwe5 fly+ fields4 ,devices to indicate compass direction & altitude are call$ = 9 new & poorly mapp$ t]ritory1 & may be expect$ to receive int5sive /udy 9 ! future4 ,! "q ( _! utility is1 h[ev]1 b\nd up ) ! :ole "q ( ! sph]e ( a]ial photographic mapp+4 ,up to ! pres5t ?is has be5 almo/ entirely a matt] ( fill+ 9 details on maps obta9$ by ! regul> survey+ me?ods1 or ( mak+ pictorial maps = aviators4 ,to :at ext5t prim>y mapp+ c be done by ! airplane is yet to be det]m9$4 ,illu/ration3 ,,fig4 #adj4--;,a /rip map1 %[+ effect ( unev5 focal plane %utt] action4 ,at ?is po9t m5tion mu/ be made ( special cam]as = secur+ extremely wide angle views1 !reby m9imiz+ ! numb] ( flights4 ,! ,bagley cam]a1 devis$ by ,major ,bagley ( ! ,u4 ,s4 ,eng9e]s1 is an example4 ,x has ?ree l5ses1 a middle "o po9t+ directly d[nw>d1 & "o to ei!r side at an angle ( #ce degrees4 ,! pictures obta9$ ) ! side cam]as are ( c\rse greatly di/ort$1 & mu/ be rectifi$ 9 a special rectify+ cam]a4 ,! resultant def9ition is n good1 b z ! maps are made on a mu* small] scale ?an ! orig9al pictures1 ?is is n a s]i\s objection4 ,x is a matt] = ! future to decide :e!r ! additional labor on ! gr\nd necess>y = ! rectify+ process is to be m exp5sive ?an ! extra flights :i* mu/ be made ) ! ord9>y types ( cam]as cov]+ a small] angle4 ,pr9t+ & ,m\nt+ ,mosaics4--,) an ord9>y set ( ov]lapp+ negatives ! fir/ /ep t[>d produc+ a map is to scale ! negatives4 ,= ?is purpose "o %\ld be select$ :i* by comp>ison ) a map %[s no di/ortion1 & :i* is on ! desir$ scale1 or is kn[n to h be5 made at ! av]age altitude ( flight4 ,a sket* map ( ! t]ritory %\ld !n be drawn1 on ?is scale1 bas$ on available maps4 ,?is sket* is pref]ably made on a l>ge gr\nd glass illum9at$ f beh9d 7,fig4 #ada74 ,on ?is all ! negatives %\ld be laid1 & _! prop] relative positions s\ght4 ,:5 ?is is done x is evid5t at once :e!r all ! t]ritory has be5 cov]$1 & :e!r !re are any sup]flu\s negatives4 ,ea* negative %\ld !n be exam9$ z to its scale & di/ortion4 ,if x c be made to fit ! scale by simple enl>gem5t or r$uction1 a l9e c be drawn on "o edge ( a l5g? indicat+ its scale4 ,?is l9e w lat] be us$ z a guide 9 ! enl>g+ cam]a4 ,if ! picture is badly di/ort$ x mu/ ei!r be replac$ by ano!r negative1 or if rectify+ app>atus is available1 x mu/ be set aside = ! mak+ ( a rectifi$ pr9t4 ,illu/ration3 ,,fig4 #ada4--,scal+ negatives = mosaic map-mak+4 ,! next /ep is to make pr9ts f ! negatives1 :i* may be done ei!r by contact1 or1 necess>ily if diff]5ces ( scale mu/ be comp5sat$1 9 ! enl>g+ cam]a4 ,if pr9ts to an exact scale are requir$ ! %r9kage ( ! pap] mu/ be det]m9$ & all[$ =4 ,! pr9ts mu/ all %[ ! same tone1 & mu/ be uni=m f edge to edge4 ,if ! focal-plane %utt] is n uni=m 9 its travel1 z is frequ5tly ! case1 ?is means t ! pr9t mu/ be 8dodg$10 or expos$ m at "o edge ?an ! o!r1 by locally %ield+ ! plate & pap] dur+ exposure4 ,a case ( ! /ep-l effect caus$ by unev5 %utt] action is %[n 9 ,fig4 #adj4 ,! effect due to unev5 %utt] action is ( c\rse abs5t ) a betwe5-!-l5s %utt]1 :i* con/itutes a /rong argum5t 9 favor ( t type = use 9 mapp+ cam]as4 ,illu/ration3 ,,fig4 #adb4--;,arrang+ pr9ts = a mosaic map4 ,:5 ! pr9ts are made !y mu/ be m\nt$ toge!r on a l>ge c>d or clo? backgr\nd4 ,= a v small mosaic !y may be juxtapos$ by simple exam9ation1 mat*+ correspond+ details 9 successive pr9ts4 ,= a mosaic ( any size an accurate outl9e map mu/ be drawn on ! surface to :i* ! pr9ts are to be atta*$4 ,! pr9ts are !n laid out on ?is outl9e1 mov$ to _! correct positions1 & held d[n by p9s 7,fig4 #adb74 ,:5 !y are all arrang$ ! f9al m\nt+ may be begun4 ,! excess pap]1 beyond :at is necess>y = safe ov]laps1 may be trimm$ (f1 ex]cis+ judgm5t z to :i* pr9t ( ea* adjac5t pair is ( ! bett] quality1 & utiliz+ x = ! top "o at ! ov]lapp+ junction4 ,if "o pr9t %[s s]i\s di/ortion x may be plac$ "u its fell[s on all f\r edges1 ?us m9imiz+ its weight4 ,! edges are be/ made irregul> by te>+4 ,/raight edges are apt to =ce !mselves on "o's att5tion 9 ! f9al mosaic & give an errone\s impression ( ! exi/5ce ( /raight roads or o!r features4 ,bo? =ms ( edg+ are %[n 9 ,figs4 #abd & #adc4 ,an alt]native me?od ( secur+ ! f9al pr9t mosaic1 :]e film negatives are us$1 is to trim successive film negatives s t ! trimm$ sections w exactly juxtapose1 in/ead ( ov]lap4 ,! sections are !n m\nt$1 by /ick]s at _! edges1 on a l>ge %eet ( glass1 & pr9t$ toge!r4 ,captur$ ,g]man pr9ts %[ t ?is 0 ! me?od commonly us$ ) ! ,g]man film cam]a 7,fig4 #fb74 ,x w be not$ t ! proc$ure :i* has be5 describ$ & illu/rat$ by ,figs4 #adb & #adc assumes ! previ\s exi/5ce ( a map accurately plac+ at lea/ ! *ief features ( ! c\ntry cov]$4 ,?is draws att5tion at once to ! limitations & true sph]e ( a]ial photographic mapp+ at ! pres5t "t4 ,) ! cam]as ?us f> x is n possible1 nor is x attempt$1 to d prim>y mapp+ ( unkn[n regions4 ,di/ortions due to l5s1 %utt]1 film w>p+ & pap] %r9kage consid]ably exce$ ! figures p]mitt$ 9 precision mapp+4 ,f ! /&po9t ( geodetic accuracy ! cumulative errors ( deviations 9 direction1 altitude & level1 peculi> to fly+1 w\ld soon become prohibitive4 ,illu/ration3 ,,fig4 #adc4--;,a p>tly complet$ map4 ,pr9ts m\nt$ ov] an outl9e sket* map to prop] scale4 ,! great field = a]ial photographic mapp+ 9 ! ne> future lies 9 fill+ 9 detail on maps h]et(ore complet$ z to g5]al outl9es1 or1 z 9 ! w>1 on maps f> out ( date4 ,! w>-"t proc$ure 9 c\ntry l>gely unkn[n1 su* z ,mesopotamia1 0 probably closely t :i* w be necess>y 9 peace4 ,conspicu\s po9ts 9 ! l&scape 7 fir/ triangulat$ f fri5dly t]ritory1 & f ^! ! outl9e map 0 drawn1 ^: details 7 to be suppli$ by a]ial photographs4 ,mu* ( ! 8mapp+0 ( cross c\ntry a]ial r\tes s f> done is frankly ( a pictorial nature1 %[+ conspicu\s l&m>ks & good l&+ fields--extremely valuable & useful1 b n to be confus$ ) precision mapp+4 ,9 assembl+ mosaics ( ?is k9d ! elaborate proc$ure describ$ above is n foll[$4 ,! process is ! simple "o ( juxtapos+ adjac5t pr9ts z accurately z possible by visual exam9ation4 ,errors are ( c\rse cumulative1 b z long z exact di/ances are n 9 "q ?is is no matt]4 ,,*apt] ,,xxvii ,,oblique ,,a]ial ,,photography ,oblique views f ! airplane are ( v great value4 ,:ile v]tical views are m se>*+ 9 _m respects1 !y d nev]!less pres5t an aspect ( ! e>? ) :i* ord9>y human exp]i5ce is unfamili>4 ,consequ5tly !y are difficult to int]pret )\t special tra9+4 ,!y suff]1 too1 f ! milit>y /&po9t1 f ! limitation t x is ) v]tical ext5sion j z mu* z ) horizontal t an army has to cont5d 9 its progress4 ,elevations & depressions ( l& %[ on an oblique view :]e !y w\ld be entirely miss$ 9 a v]tical "o4 ,= illu/ration1 /udy ! picture ( "p ( ! outskirts ( ,arras 7,fig4 #add71 pres5t+ moat1 walls & embankm5ts1 all ( :i* w\ld be s]i\s ob/acles1 b w\ld h>dly be notic$ on a v]tical view4 ,pictures tak5 f directly ov]head are em95tly suit$ to artill]y use1 b oblique views ( ! t]ritory to be attack$1 tak5 f l[ altitudes1 =m$ an ess5tial "p ( ! equipm5t ( ! infantry 9 ! lat] /ages ( ! w>4 ,pictorially1 oblique views are und\bt$ly ! mo/ satisfactory4 ,! mo/ reveal+ aspect ( any object is n "o side or face alone1 b ! view tak5 at an angle1 %[+ portions ( two or ?ree sides4 ,be/ ( all is t tak5 to %[ portions ( front1 side & top--! well-kn[n b h]et(ore fictiti\s 8bird's-eye view0 7,fig4 #ade74 ,?is possibility is ord9>ily d5i$ ! surface-(-!-e>? photograph]1 b ! prop] vantage po9t is atta9$ 9 ! airplane4 ,a]ial obliques may be tak5 at any angle1 al?\gh a di/9ction is sometimes made betwe5 obliques ( high angle & panoramic or l[ angle views 7,fig4 #adf74 ,9 addition to ord9>y obliques1 a v beautiful developm5t is ! /]eo oblique4 ,bo? k9ds ( oblique photography call = special in/rum5tal equipm5t & te*nique4 ,illu/ration3 ,,fig4 #add4--,! outskirts ( ,arras4 ,l[ oblique %[+ cont\rs4 ,me?ods & ,app>atus = ,oblique ,photography4--,! simple/ me?od ( tak+ oblique pictures f a plane is to use a h& cam]a po9t$ at ! desir$ angle4 ,its limitations are 9 ! size & scale ( ! picture obta9able1 & 9 ! inh]5t limitations to ! me?od ( cam]a support4 ,a /ep 9 advance ( ?is is to m\nt ! cam]a above ! fuselage1 on ! ma*9e gun r+ or turret1 9 place ( ! gun4 ,consid]ably great] rigidity is ?us obta9$1 & heavi] cam]as c be utiliz$1 al?\gh ! w9d resi/ance is a s]i\s factor4 ,excell5t obliques h be5 made 9 ?is way1 ev5 ) #ej-;c5timet] cam]as1 b ! s*eme is impractical 9 milit>y planes1 because ( ! removal ( ma*9e gun protection4 ,illu/ration3 ,,fig4 #ade4--,oblique view ( ,capitol & ,congressional ,libr>y1 ,wa%+ton4 ,illu/ration3 ,,fig4 #adf4--;,=t ,alv5sleg51 ne> ,metz4 ,photo by ,photographic ,section ,a4 ,e4 ,f4 ,if ! cam]a is fix$ 9 ! fuselage 9 its normal v]tical position1 obliques may be & h be5 tak5 by ! simple exp$i5t ( bank+ ! plane /eeply4 ,?is is n to be recomm5d$ z a /&>d proc$ure1 especially = tak+ a consecutive s]ies ( exposures4 ,! mo/ satisfactory arrangem5ts = tak+ obliques are two2 fir/1 to m\nt ! cam]a obliquely 9 ! plane1 & second1 to use a mirror or prism1 9 front or beh9d ! l5s ( ! v]tically m\nt$ cam]a4 ,! fir/ me?od has be5 employ$ *iefly by ! ,fr5*1 ! latt] by ! ,engli%1 ^: gravity f$ cam]as c\ld n be m\nt$ obliquely4 ,tak+ up fir/ ! oblique m\nt+ ( cam]as1 we f9d two ways ( do+ ?is3 longitud9al m\nt+ & lat]al m\nt+4 ,9 longitud9al m\nt+ ! cam]a projects =w>d & d[nw>d1 usually f ! nose ( a pu%] or bi-motor$ plane4 ,) ?is =m ( m\nt+ 7,fig4 #adg7 x is necess>y ( c\rse to fly directly t[>d ! objective4 ,if ?is is a portion ( enemy tr5*1 :i* mu/ be photograph$ f a height ( #djj or #ejj met]s1 ! plane w be directly on top ( its objective a few seconds aft] ! exposure is made1 & be a conspicu\s t>get1 9 imm95t dang] ( de/ruction4 ,moreov]1 only a s+le %ort section ( ! tr5* w\ld be obta9$ = ea* cross+ ( ! l9e4 ,! "o case :]e resort to ?is me?od is practically =c$ is ) ! #abj-;c5timet] cam]as :i* simply _c be slung a?w>t ! plane4 ,!re is a slight advantage 9 ?is me?od ( c>ry+ 9 t ! motion ( ! image is less if ! objective is approa*$1 in/ead ( be+ pass$ at ! side1 & s long] exposures c be made4 ,! longitud9al m\nt+ has1 h[ev]1 be5 v g5]ally sup]s$$ by ! lat]al4 ,illu/ration3 ,,fig4 #adg4--abj-;c5timet] cam]a m\nt$ obliquely 9 ! =e-&-aft position4 ,me?ods = m\nt+ cam]as obliquely = tak+ pictures ?r\gh ! side ( ! plane h be5 discuss$ 9 detail 9 connection ) cam]a m\nt+s & in/allations 7,fig4 #ic74 ,! *ief difficulties are want ( space1 ob/acles at ! side su* z control wires & long]ons1 & failure ( ! cam]a to function prop]ly at an angle4 ,ev5 9 ! broad circul> section$ fuselage ( ! ,salmson plane1 qu>t]s are s cramp$ t ! ,fr5* #ej-;c5timet] cam]a :5 obliquely m\nt$ _c be us$ ) ! #ab-plate magaz9e1 & rec\rse is made to ?9 flat d\ble plate-hold]s4 ,holes 9 ! side ( ! fuselage %\ld cle> all wires & %\ld comm& a view unob/ruct$ by ! w+s--:i* (t5 means t ! cam]a mu/ be c>ri$ beh9d ! obs]v]'s cockpit1 irrespective ( ! suitability ( t space f o!r /&po9ts4 ,cam]as dep5d5t = _! action on gravity1 su* z ! de,ram & ,engli% ,l type1 are unsuit$ = oblique susp5sion4 ,illu/ration3 ,,fig4 #adh4--,mirror on cam]a cone = tak+ oblique views4 ,= cam]as :i*1 because ( _! me?od ( op]ation or %ape _c be slung obliquely1 ! only way to take obliques is to employ mirrors 7,fig4 #adh7 or prisms4 ,^! mu/ be ( ! same optical quality z ! photographic l5s4 ,!y are bo? necess>ily ( consid]able weight because !y mu/ be ( l>ge area ( face to fill ! entire ap]ture ( an a]ial l5s4 ,mirrors are light] ?an prisms1 b mu/ be q ?ick to prev5t di/ortion ( ! surface due to any possible /ra9s to _! m\nt4 ,"r angle glass prisms h be5 us$ by ! ,engli% ) ! #h & #aj in* ,l cam]as4 ,! prisms 7 uni=mly tilt$ to an angle ( #ab degrees f ! horizontal4 ,glass mirrors c be silv]$ ei!r on ! re> or front surface4 ,if on ! re>1 bo? surfaces mu/ be accurately p>allel1 :i* means mu* great] labor & exp5se ?an if ! front surface c be utiliz$4 ,! difficulty ) front surface mirrors is t ! metallic coat+ is easily t>ni%$ or scrat*$1 especially if silv] is us$1 :i* is almo/ imp]ative1 s9ce all ! o!r metals h consid]ably l[] reflect+ p[]s4 7,gold might s]ve bo? z mirror & color filt]1 because ( its yell[ color47 ,plac+ ! mirror inside ! cam]a body 9 "p obviates ?is tr\ble1 b means ! use ( a special elb[ l5s cone4 ,9 any case ! mirror or prism occasions at lea/ a #aj p] c5t4 loss ( light4 ,pictures tak5 by reflectors ( any k9d are rev]s$1 & mu/ ei!r be pr9t$ 9 a cam]a1 or on transp>5t film :i* may be view$ f ! back4 ,! mo/ usual condition = mak+ obliques is to fly v l[ 7#cjj to #fjj met]s71 ) ! l9e ( sight ( ! cam]a f #ab to #de degrees f ! horizontal4 ,?is l[ altitude necessitates v %ort exposures1 to avoid movem5t ( ! image4 ,! picture may be tak5 ei!r ! long or ! %ort way ( ! plate1 dep5d+ on ! "* ( ! object & ! in=mation desir$4 ,x is to be not$ t successive oblique pictures _c be m\nt$ to =m a cont9u\s panorama--?is be+ possible ) obliques only if !y are tak5 f "o po9t1 z f a captive balloon4 ,if successive views are made on a /raight flight at int]vals s z to exactly juxtapose 9 ! =egr\nd1 !y ov]lap by a l>ge m>g9 ! middle1 & a po9t on ! horizon1 if t %[s1 w be 9 ! same position 9 e picture4 ,mosaics ( obliques c\ld be made only by "s sy/em ( conical m\nt+4 ,sights = ,oblique ,photography4--,any ( ! sights previ\sly discuss$ = v]tical "w1 su* z ! tube sights1 are applicable to obliques4 ,!y mu/1 h[ev]1 be suit$ = m\nt+ at an angle1 9 a position conv5i5t = ! obs]v]4 ,9 addition1 provision mu/ be made = adju/+ ! angle s t ! l9es ( sight ( cam]a & f9d] are p>allel4 ,m\nt+ outside ! fuselage is practically ! only feasible way1 & is less objectionable ) oblique ?an ) v]tical sights1 z oblique sight+ does n require ! obs]v] to /& up & lean ov] ! edge ( ! cockpit4 ,w9d[s 9 ! side ( ! fuselage1 ei!r ( celluloid or non-breakable glass1 are a great aid to oblique obs]vation4 ,m>ks ^u ! transp>5t surface c be utiliz$ = ! re> po9ts ( a sight ( :i* ! front po9t is a s+le fix$ bead or rectangle4 ,,*apt] ,,xxviii ,,/]eoscopic ,,a]ial ,,photography ,"o ( ! mo/ /rik+ & valuable developm5ts 9 a]ial photography has be5 ! use ( /]eoscopic views4 ,pairs ( pictures1 tak5 ) a consid]able sep>ation 9 _! po9ts ( view & /udi$ lat] by ! aid ( ! /]eoscope1 %[ an elevation & a solidity :i* are entirely want+ 9 ! ord9>y flat a]ial vi/a4 ,(t51 inde$1 ^! attributes are ess5tial = detect+ & recogniz+ ! nature ( objects se5 f above4 ,/]eoscopic a]ial photography has be5 ju/ly t]m$ 8! wor/ foe ( cam\flage40 ,pr9ciples ( ,/]eoscopic ,vision4--,! ability to see objects 9 relief is conf9$ solely to man & to a few ( ! high] animals 9 :om ! eyes are plac$ side by side4 ,:5 ! eyes are s plac$ !y bo? see1 to a l>ge ext5t1 ! same objects 9 _! fields ( view4 ,ow+ to ! sep>ation ( ! eyes ! actual appe>ance ( all objects n too f> away is diff]5t1 & x is by ! int]pretation ( ^! diff]5ces t ! bra9 gets ! s5sation ( relief4 ,?us 9 ,fig4 #adi ! two eyes are %[n diagrammatically z look+ at a cube4 ,! "r eye sees ar\nd on ! "r-h& face ( ! cube1 ! left eye on ! left-h& face ( ! cube4 ,! two aspects :i* are fus$ & int]pret$ by ! bra9 are %[n 9 ! l[] diagram4 ,/]eoscopic views or /]eograms1 made ei!r by photography or1 9 ! e>ly days1 by c>eful draw+1 consi/ ( pairs ( pictures made ( ! same object f two diff]5t po9ts4 ,= ord9>y /]eoscopic "w ^! po9ts are sep>at$ by ! di/ance betwe5 ! eyes1 approximately #fe millimet]s or #b in*es4 ,^! two pictures are !n s view$ t ea* eye receives its appropriate image f ! prop] direction1 :]eupon ! object del9eat$ /&s out 9 relief4 ,illu/ration3 ,,fig4 #adi4--,! pr9ciple ( /]eoscopic vision4 ,fusion ( ! two elem5ts ( ! /]eoscopic picture c take place )\t ! assi/ance ( any in/rum5t1 if ! eyes are prop]ly direct$ & focuss$1 b ?is comes only ) practice4 ,hold+ ! /]eogram well away f ! face ! eyes are direct$ to a di/ant object above & beyond1 9 ord] to div]ge ! axes4 ,!n )\t conv]g+1 ! eyes are dropp$ to ! picture1 :i* %\ld spr+ into relief4 ,x is necess>y 9 mov+ ! eyes f ! di/ant object to ! ne> /]eogram to alt] _! focus some:at1 dep5d+ on h[ ne> ! /]eogram is held2 & ! success ( ! attempt to fuse ! images dep5ds on ! obs]v]'s ability to ma9ta9 ! eyes div]g$ = a di/ant object :ile focuss+ = a ne> "o4 ,ne>-sight$ p 7on tak+ (f _! glasses7 fuse ! /]eoscopic images q easily1 s9ce _! eyes d n focus on di/ant objects ev5 :5 div]g$ = !m4 ,transp>5cies are easi] to fuse ?an pap] pr9ts1 b 9 any case :]e a /]eoscope is n us$ ! sep>ation ( image c5t]s %\ld n be m ?an t ( ! eyes4 ,illu/ration3 ,,fig4 #aej4--;,common =m ( prism /]eoscope4 ,/]eoscopes4--,! easi] & m usual me?od ( fus+ ! /]eoscopic images is by a /]eoscope4 ,! simple/ =m consi/s m]ely ( two convex l5ses1 "o = ea* eye1 _! c5t]s sep>at$ by a di/ance some:at great] ?an t betwe5 ! eyes4 ,_! function is to br+ ! /]eogram to focus1 &1 by ! prismatic action ( ! edges ( ! l5ses1 to conv]ge ! l9es ( sight :i* pass ?r\gh ! c5t]s ( ! two pictures to a po9t 9 space 9 front ( ! obs]v]4 ,! two l5ses %\ld be m\nt$ s z to provide = ! adju/m5t ( _! sep>ation to fit diff]5t eyes & pr9t spac+s4 ,! mo/ common =m ( /]eoscope is t design$ by ,holmes1 = view+ pap] pr9t /]eograms 7,fig4 #aej74 ,x has prismatic l5ses ( an appropriate angle to conv]ge pictures ^: c5t]s are ?ree in*es ap>t1 in/ead ( ! less] di/ance appropriate to /]eograms int5d$ = fus+ )\t an in/rum5t4 ,no adju/m5t is provid$ = v>y+ ! l5s sep>ation1 b ! pr9t c be mov$ to & fro = focuss+4 ,illu/ration3 ,,fig4 #aea4--;,box /]eoscope4 ,illu/ration3 ,,fig4 #aeb4--;,diagram ( mirror /]eoscope4 ,ano!r =m ( /]eoscope1 "o ( ! fir/ produc$1 is ! mirror /]eoscope 7,fig4 #aeb71 n[ us$ ext5sively = view+ /]eo ,x-ray pictures4 ,x consi/s ( two v]tical mirrors at "r angles to ea* o!r1 ) _! edge ( contact betwe5 ! eyes4 ,! two pr9ts to be /udi$ are plac$ to "r & left1 an arrangem5t t p]mits ! use ( pr9ts ( any size4 ,! conv]g5ce po9t is controll$ by ! angle betwe5 ! mirrors4 ,! ,pell9 /]eoscope 7,fig4 #aec7 utilizes two pairs ( mirrors 9 a way to p]mit ! use ( l>ge pr9ts4 ,! pr9ts are1 h[ev]1 plac$ side by side on a horizontal view+ table1 :i* avoids c]ta9 difficulties ( illum9ation met ) 9 ! simpl] mirror =m4 ,! box =m ( /]eoscope 7,fig4 #aea7 us+ ei!r prisms or simple convex l5ses1 is p>ticul>ly adapt$ = view+ transp>5cies1 al?\gh ! ins]tion ( a door at ! top provides illum9ation = pap] pr9ts4 ,! ,s*weissgu? design 7,fig4 #aed7 is int5d$ prim>ily z an aid to select+ ! portions ( ! pr9ts to be cut out = m\nt+4 ,! plat=m on :i* ! pictures re/ is compos$ ( two long rectangul> blocks1 on :i* are plates ( glass rais$ suffici5tly to p]mit ! pr9ts to be slid und]nea?4 ,! space betwe5 ! blocks all[s ! unus$ portion ( ! photograph to be turn$ d[n out ( ! way4 ,pr9ts ( any size c ?us be mov$ ab\t until ! prop] portions = /]eo m\nt+ are f\nd4 ,ei!r block c be mov$ 9 its own plane & also to & f ! eye1 :]eby two pr9ts ( some:at diff]5t scales c be fus$4 ,illu/ration3 ,,fig4 #aec4--,pell9 d\ble mirror /]eoscope4 ,! ,tak+ ( ,a]ial ,/]eograms4--,! normal sep>ation ( ! eyes is altoge!r too small to give an appe>ance ( relief to objects z f> away z is ! gr\nd f a plane at ord9>y fly+ heights4 ,9 ord] to secure /]eoscopic pairs x is !re=e necess>y to resort to a me?od orig9ally employ$ = photograph+ di/ant m\nta9s & cl\ds4 ,?is is to take ! two pictures f po9ts sep>at$ by di/ances mu* great] ?an ! int]ocul> sep>ation--by met]s in/ead ( millimet]s--correspond+ to ! positions ( ! eyes on a v]itable giant4 ,9 ! airplane ?is is accompli%$ by mak+ successive exposures z ! plane flies ov] ! objective1 at int]vals to be det]m9$ by ! spe$1 ! altitude & ! am\nt ( relief desir$ 7,fig4 #aee74 ,an all important "q :i* arises imm$iately is3 ,:at sep>ation ( po9ts ( view %all we select8 ,if ! exposures are too close toge!r !re w be little relief2 if too di/ant ! relief w be s great z to be unnatural1 ev5 (f5sive4 ,obvi\sly we _c "h e/abli% a crit]ion ( natural appe>ance1 s9ce ! natural appe>ance to ord9>y human eyes is devoid ( relief4 ,we may1 h[ev]1 def9e correct relief z t obta9$ :5 ! app>5t height ( elevat$ objects is "r z comp>$ ) _! ext5sion or plan4 ,illu/ration3 ,,fig4 #aed4--,s*weissgu? /]eoscope1 us$ = select+ portions ( pr9ts to be m\nt$4 ,illu/ration3 ,,fig4 #aee4--,me?od ( tak+ /]eoscopic pictures4 ,9 ord] to secure ?is condition x is necess>y1 fir/1 t ea* elem5t ( ! /]eoscopic pair be correct 9 its p]spective4 ,?is is =tunately an old photographic problem1 already well und]/ood4 ,its solution is to view ! photograph f a di/ance exactly equal to ! focal l5g? ( ! cam]a l5s4 ,s9ce ! normal view+ di/ance is n less ?an #be c5timet]s1 l5ses ( ?is focal l5g? at lea/ are requisite = correct p]spective4 ,secondly1 x is necess>y = correct relief t ! two views be tak5 ) a sep>ation equal1 on ! plane ( ! plate1 to ! sep>ation ( ! eyes1 or #fe millimet]s4 ,if d is ! int]ocul> di/ance1 a ! view+ di/ance1 id5tical ) ! focal l5g? ( ! l5s us$1 & ,a ! altitude1 !n ,d1 ! di/ance betwe5 exposures1 is giv5 by ! relation-- d ,d ------ ------ a ,a ,= a #be c5timet]s1 ,d_/,a #f4e_/be1 approximately 1 or ! int]val betwe5 exposures mu/ be a qu>t] ! altitude4 ,) a #ej c5timet] l5s ?is becomes 1 & s on4 ,^! figures %[ ! fallacy ( ! sugge/ion sometimes made t we take /]eoscopic pictures by two cam]as plac$ "o at ! extremity ( ea* w+4 ,:5 l5ses ( m ?an #be c5timet]s focal l5g? are employ$1 ! /]eoscope %\ld be "o capable ( ?r[+ ! conv]g5ce po9t f>!r away ?an ! cu/om>y #be c5timet]s4 ,9 ! simple l5s type ( in/rum5t we c d ?is by br++ ! c5t]s ( ! l5ses clos] toge!r1 & by mak+ ! focus agree ) ! conv]g5ce po9t by adju/m5t ( ! di/ance betwe5 l5ses & /]eogram4 ,if enl>gem5ts are us$ !y %\ld be treat$ 9 all respects z orig9als made by l5ses ( ! great] foci correspond+ to ! scale ( ! enl>gem5t4 ,:5 all ! conditions are cov]$1 ! appe>ance pres5t$ 9 ! /]eoscope is t ( a model ( ! orig9al object at a di/ance a1 & a_/,a times natural size4 ,if pictures are made at exposure int]vals less ?an ^? indicat$ = correct relief1 !y %[ insuffici5t relief4 ,?is does n1 h[ev]1 give an unnatural effect1 because any?+ betwe5 no relief & 8correct0 relief appe>s natural ) l>ge objects :i* are n ord9>ily se5 9 relief by eyes n ,brobdignagian4 ,conv]sely1 /]eograms made ) too l>ge exposure int]vals %[ exagg]at$ relief4 ,yet ?is is (t5 no objection4 ,x is inde$ r an advantage if we wi% to br+ objects ( int]e/ to notice4 ,consequ5tly1 s long z ! exagg]ation ( relief is n (f5sive1 ! p]missible limits ( exposure int]val are pretty l>ge4 ,actually1 ! eye tol]ates su* great deviations f /rictly normal conditions t satisfactory /]eoscopic effects are obta9$ = pictures view$ at v diff]5t di/ances f ! focal l5g? ( ! tak+ l5s1 & ) ! axes ( ! eyes p>allel or ev5 div]g+1 al?\gh !re is "s /ra9 :5ev] focus & conv]g5ce po9ts diff]4 ,on ! :ole1 !re=e1 x may be said t ! conditions above laid d[n = correct relief are only a normal1 to be approximat$ z ne>ly z is practicable4 ,hav+ e/abli%$ ! correct relation ( tak+ po9ts = /]eos ! next problem is h[ to det]m9e ^! :5 9 ! plane4 ,! simple/ way is by means ( a /]eoscopic sight4 ,?is consi/s ess5tially ( two l9es ( sight 7fix$ by beads1 crosses1 or o!r objects71 incl9$ t[>d ea* o!r at ! angle det]m9$ by ! ratio ( ! ocul> sep>ation to ! focal l5g? ( ! l5s4 ,if ! back sight is made a s+le bead or cross1 ! re/ ( ! /]eo sight w consi/ ( two beads or crosses1 sep>at$ f ea* o!r by ! ocul> di/ance ( #fe millimet]s1 & di/ant f ! back sight by ! focal l5g? ( ! l5s 7,fig4 #aeg74 ,! fir/ picture is tak5 :5 ! object is 9 l9e ) ! =w>d po9t+ l9e ( sight1 ! second :5 x lies along ! backw>d po9t+ "o4 ,l o!r sights1 ! /]eoscopic sight may be atta*$ ei!r to ! cam]a1 or if ?is is fix$ 9 position1 to any conv5i5t "p ( ! plane4 ,a v simple sight = v]tical /]eoscopic photography consi/s ( an inv]t$ ,v pa9t$ on ! side ( ! fuselage1 s t ! eye c be plac$ at ! v]tex & sight$ along ei!r leg4 ,! common me?od ( det]m9+ ! space betwe5 exposures is by ! "t int]val4 ,if ,v is ! spe$ ( ! plane1 & t ! desir$ "t int]val1 we h1 f ! la/ equation-- ,d d,a t ------ -------- ,v a,v ,if ,a #bjjj met]s1 d #fe millimet]s1 & a #be c5timet]s1 & if ! plane is travel+ #bjj kilomet]s p] h\r1 ! "t int]val mu/ be-- 4#jfe #bjjj #cfjj ------------------------------------ #i4d seconds 4#be #bjj1jjj ,at #ajjj met]s altitude ! int]val w be half ?is1 & s on 9 proportion4 ,if ! pictures are tak5 ) a #ej c5timet] focus cam]a1 & are h5ce to be view$ at #ej c5timet]s conv]g5ce di/ance in/ead ( at #be1 ! "t w aga9 be halv$4 ,^! relations are cle>ly %[n 9 ! diagram 7,fig4 #aef74 ,"h ! left-h& portion %[s h[ to f9d ! /]eoscopic base l9e at ea* altitude = ea* focal l5g?2 :ile ! "r-h& portion %[s h[ to translate ?is into "t int]val = any plane velocity4 ,! ,bur*all slide rule 7,fig4 #acj7 %[s ano!r way to arrange ^! data 9 =m = rapid calculation4 ,illu/ration3 ,,fig4 #aef4--;,*>t = calculat+ int]vals betwe5 exposures = /]eoscopic pictures4 ,plates us$ = /]eoscopic negatives %\ld be at lea/ twice z long z ! ocul> sep>ation1 if correct relief is desir$1 & ! full size ( ! /]eoscope field is to be utiliz$4 ,?is relation foll[s at once if we consid] t we wi% to cut f ea* negative a rectangle #fe millimet]s wide1 & t ! image ( ! t>get has %ift$ #fe millimet]s betwe5 exposures4 ,if ! plate is l>g] ?an ?is !re is opportunity to select ! view1 or to pick sev]al4 ,if ! plate is small] ! elem5ts ( ! /]eogram mu/ be n>r[ /rips4 ,?is1 h[ev]1 holds only = contact pr9ts4 ,! ord9>y ,engli% practice 9 mak+ /]eo negatives is to take successive pictures ) an ov]lap ( #fj to #ge p] c5t4 ,?is practice is probably dictat$ by ! #d #e in* plate1 s9ce #fj p] c5t4 ov]lap on #d in*es means a sep>ation ( j ov] an in* & a half in/ead ( #b1 b x leaves #b in*es ( picture common to ! two negatives4 ,) ov]lap ! common portion is #c in*es1 :i* p]mits ( cutt+ #b in* pr9ts1 & all[s "s latitude = irregul> motion ( ! plane or = *ance error 9 calculation ( int]vals4 ,data on ! basis ( ov]laps = a #d-;in* plate are %[n 9 connection ) ,fig4 #aee :i* %[s 9 diagrammatic =m ! v>iation ( exposure int]val ) height1 toge!r ) o!r po9ts ( int]e/4 ,elevation ,possible to ,detect 9 ,/]eoscopic ,views4--,c ! actual diff]5ce 9 elevation be discov]$ by ! use ( /]eoscopic views8 ,an approximate idea may be obta9$ f ! foll[+ consid]ations3 ,suppose we h two small po9t-l objects1 "o above ! o!r1 su* z a /reet lamp globe & ! base ( ! lamp pill>4 ,9 a view tak5 f directly ov]head ^! w be sup]pos$1 & s w n be capable ( sep>ation4 ,b1 z ! po9t ( view is %ift$ sideways1 ! two objects sep>ate1 until a po9t is rea*$ :]e !y c j be di/+ui%$ z d\ble4 ,:5 ?is condition holds = ei!r picture ( ! /]eoscopic pair x w be possible to obta9 /]eoscopic relief4 ,n[ ! sep>ation :i* c j be di/+ui%$ is commonly assum$ to be "o m9ute ( arc4 ,?is angle corresponds to ab\t #a_/cdjj ! di/ance f ! eye to ! object4 ,if ! object is assum$ at a di/ance a f ! face1 & on a l9e ) "o ( ! eyes1 :i* are sep>at$ by ! di/ance d1 !n 7all angles be+ small7 ! object mu/ be ( height a_/d times ! horizontal di/ance :i* corresponds to "o m9ute4 ,= #be c5timet]s' view+-di/ance ?is quantity is ab\t #d1 s t ! lea/ p]ceptible elevation is #d_/cdjj or ab\t #a_/ijj4 ,! /]eogram hav+ be5 made "u conditions giv+ correct relief1 ?is fraction is also ! fraction ( ! altitude ( ! plane :5 ! photograph 0 tak5 :i* may be detect$4 ,an object z high z a man 7#f feet7 %\ld be visible z a projection 9 a /]eoscopic view tak5 at #f #ijj #edjj feet4 ,?is relation--#a_/ijj--;holds 7irrespective ( ! focal l5g? ( ! l5s71 z long z ! conditions = correct relief are ma9ta9$4 ,/]eoscopic ,a]ial ,cam]as4--,cam]as = a]ial /]eoscopic photography ne$ 9 no way diff] 9 con/ruction f ^? made = mapp+ or spott+1 provid$ only !y p]mit exposures to be made at %ort en\gh int]vals4 ,! addition ( special sights1 z already discuss$1 con/itutes ! only real diff]5ce betwe5 s+le view & /]eoscopic a]ial cam]as4 ,b ev5 )\t su* sights ord9>y a]ial cam]as are applicable to /]eo "w by ! usual proc$ure ( det]m9+ ! exposure spac+ by "t4 ,"o s*eme employ$ = tak+ l[ /]eos1 :]e ! int]val is only two or ?ree seconds1 is to m\nt two cam]as 9 ! plane1 expos+ !m "o aft] ! o!r at ! correct int]val4 ,ano!r me?od :i* has be5 tri$ ) success is ! use ( a d\ble focal-plane %utt] 9 a s+le l5s cam]a 7,fig4 #aeg74 ,! two %utt]s are side by side1 ) _! slots p>allel to ! l9e ( flight4 ,to take a /]eo negative we expose fir/ ! %utt] ne>] ! tail ( ! plane1 & !n ! o!r1 aft] an int]val :i* c be calculat$ f ! spe$ & altitude1 or1 bett]1 det]m9$ by a /]eoscopic sight4 ,! two views are ?us obta9$ on a s+le plate4 ,pr9ts f ^! negatives are transpos$ "r & left1 &1 if ! pr9ts are view$ 9 an ord9>y /]eoscope1 h to be cut ap>t & transpos$ = m\nt+1 or else ?is may be done to ! negatives4 ,illu/ration3 ,,fig4 #aeg4--;,a]ial h& cam]a fitt$ ) two complim5t>y %utt] slits & d\ble sight1 = /]eoscopic photography4 ,9 ?is connection att5tion may be drawn to an alt]native me?od ( view+ /]eograms1 :i* may be us$ on transpos$ pr9ts--a me?od :i* ne$s no in/rum5t1 & s has suffici5t advantage to ev5 w>rant m\nt+ ord9>y /]eoscopic pairs 9 ! transpos$ position = obs]vation4 ,?is me?od consi/s 9 cross+ ! optic axes1 9 ! fa%ion illu/rat$ 9 ,fig4 #aeh4 ,a f+] is held 9 front ( ! face 9 su* a position t ! left /]eogram elem5t & ! f+] are se5 9 l9e by ! "r eye2 ! "r elem5t & ! f+] by ! left eye4 ,! prop] position is f\nd by alt]nately clos+ ea* eye1 & advanc+ or retract+ ! f+]4 ,!n bo? eyes are op5$ & conv]g$ on ! f+] tip1 :i* is !reupon dropp$1 leav+ ! picture /&+ out 9 relief4 ,an opportunity to try ?is me?od is af=d$ by ,fig4 #aei4 ,illu/ration3 ,,fig4 #aeh4--,me?od ( fus+ transpos$ /]eoscopic images by cross+ ! optic axes4 ,/]eo ,obliques4--,! !ory ( mak+ oblique /]eo pictures is id5tical ) t ( o!r /]eos4 ,! only problem peculi> to obliques is t ( mak+ ! exposures at %ort en\gh int]vals ap>t4 ,?is problem is due l>gely to ! fact t oblique views are ord9>ily tak5 f l[ altitudes1 = ! purpose ( 8spott+0 p>ticul> objects1 r ?an = mapp+ ! gross features ( an ext5d$ area4 ,! same problem ( h[ to secure a %ort exposure int]val is met ) :5 we attempt to take v]tical /]eos f a l[ altitude1 b z already discuss$1 x is mu* pref]able f ! pictorial /&po9t t pictures ( def9ite small objectives be made obliquely4 ,ano!r reason = tak+ /]eo obliques f po9ts b little sep>at$ is ( "s int]e/ 9 connection ) ! discussion above giv5 ( 8correct0 & 8natural0 relief4 ,:5 ! relief is 8correct0 ! object appe>s1 z already /at$1 to be a small model 9 its true proportions1 /&+ at ! conv]g5ce di/ance4 ,:5 ! eyes are conv]g$ to a small object #be to #ej c5timet]s away all objects beyond are hopelessly transpos$ & confus$4 ,?is does n happ5 :5 we look at l>ge di/ant objects1 s9ce _! backgr\nd is at a di/ance effectively b little beyond !m4 ,z a result1 :5 a /]eo oblique is made 9 8correct0 relief ( su* an object z ! ,wa%+ton monum5t ) build+s beyond1 ! confusion ( ! backgr\nd pres5ts an appe>ance entirely contr>y to our visual exp]i5ce ) objects z l>ge z ! neighbor+ build+s are kn[n to be4 ,?is effect may be avoid$ by *oos+ a uni=m backgr\nd su* z grass1 or by tak+ ! pictures v mu* clos] toge!r1 at ! exp5se ( 8correct0 b at a ga9 9 8natural0 relief4 ,/]eo obliques c ( c\rse only be made ) any facility by lat]ally po9t+ cam]as4 ,f ! calculations already giv5 x appe>s t a 8correct0 /]eo oblique ( an object #ejj met]s away w mean exposures only two or ?ree seconds ap>t1 too %ort an int]val = any ( ! ord9>y plate-*ang+ & %utt]-sett+ me*anisms2 & ! case is ev5 worse %\ld less relief be desir$4 ,"o solution ( ?is problem has be5 ! use1 already m5tion$1 ( two cam]as m\nt$ toge!r1 ei!r side by side or "o ov] ! o!r1 ) sep>ate %utt] releases4 ,bo? releases may be controll$ by ! obs]v]1 us+ a sight1 or else pilot & obs]v] may "w 9 h>mony z has be5 recomm5d$ 9 ! ,engli% s]vice1 :]e ! pilot releases "o %utt] & ! obs]v] c\nts "t f ! in/ant he sees ! fir/ %utt] unw9d & releases ! second4 ,illu/ration3 ,,fig4 #aei4--,oblique /]eogram made ) /]eoscopic a]ial cam]a 7,fig4 #aeg74 ,to be view$ by cross+ ! optic axes 7,fig4 #aeh74 ,a v satisfactory app>atus = ! tak+ ( /]eo obliques consi/s ( a #aj-;in* focus h&-held cam]a 7,fig4 #aeg71 provid$ ) a two-ap]ture focal-plane %utt]4 ,! "r-h& half ( "o curta9 ap]ture is block$ out1 ! left-h& half ( ! o!r4 ,! fir/ pressure on ! expos+ lev] exposes "o-half ( ! plate1 ! second ! o!r4 ,a /]eoscopic sight ( ! type already describ$ is plac$ on ! bottom4 ,to make an oblique /]eo negative ! cam]a is held rigidly by re/+ ! elb[s on ! top ( ! fuselage & ! fir/ exposure is made :5 ! object comes 9 l9e ) ! re> sight & ! lead+ front sight4 ,! eye is !n mov$ s z to look along ! l9e ( ! re> sight & ! foll[+ front sight1 & :5 ! object is aga9 9 al9em5t ! second pressure is giv5 ! expos+ lev]4 ,fig4 #aei %[s a /]eo oblique made by ?is cam]a4 ,! elem5ts are transpos$ "r & left1 & ! /]eogram may be view$ by cross+ ! optic axes z %[n 9 ,fig4 #aeh1 or ! two pictures may be cut ap>t & rem\nt$4 ,! ,m\nt+ ( ,a]ial ,/]eograms4--,! fir/ /ep 9 mak+ ! pr9t$ /]eogram is to select two pictures tak5 on ! same scale1 b f slightly diff]5t positions4 ,^! may be two *os5 f a collection made = o!r purposes1 or else a pair tak5 at di/ances calculat$ to fit !m = /]eoscopic use4 ,! next /ep is to m>k ! c5t] ( ea* picture1 ei!r ) easily remov$ *alk or ) a p9 po9t4 ,!y are !n sup]pos$1 & aft]w>d c>efully mov$ ap>t by a motion p>allel to ! l9e jo9+ _! c5t]s :5 sup]pos$4 ,! f9al /ep be=e m\nt+ is to m>k out & cut ! two elem5ts1 _! bases be+ p>allel to ! l9e ( c5t]s1 _! horizontal l5g? ! di/ance betwe5 ! optic axes ( ! /]eoscope 7or z ne> ?is z ! size ( ! pr9ts w p]mit74 ,!y are !n m\nt$ on a c>d1 ) _! c5t]s sep>at$ by approximately #fe millimet]s4 ,! "r-h& view is ! "o %[+ m ( ! "r-h& side ( objects1 & vice v]sa4 ,?is process ( arrang+1 cutt+1 & m\nt+ is %[n cle>ly 9 ,fig4 #afj4 ,9 ?is case ! /]eoscopic elem5ts lie symmetrically ab\t ! l9e jo9+ ! c5t]s ( ! orig9al pr9ts4 ,?is is n necess>y1 z !y may be select$ f above or bel[ ?is l9e s long z _! bases are p>allel to x4 ,a simplification ( ?is me?od consi/s 9 sup]pos+ ! two pr9ts1 lay+ ov] !m a squ>e ( glass ( ! size to :i* !y are to be cut1 !n turn+ x s t a side is p>allel to ! l9e ( c5t]s1 & cutt+ ar\nd x ?r\gh bo? pr9ts ) a %>p knife4 ,! pr9ciple & results are ( c\rse ! same ) bo? me?ods4 ,illu/ration3 ,,fig4 #afj4--,me?od ( arrang+ /]eoscopic pr9ts = cutt+4 ,if l>ge numb]s ( /]eoscopic pr9ts are requir$ x is necess>y1 = economy ( "t1 ei!r to photograph a f9i%$ /]eogram & make pr9ts f ?is copy negative1 or to set up special pr9t+ ma*9es4 ,"u ! g5]al discussion ( pr9t+ devices a /]eoscopic pr9t] is describ$ 7! ,ri*>d7 9 :i* ! two negatives are plac$ s t /]eo pr9ts c be got by two successive pr9t+s on "o %eet ( pap]4 ,uses ( ,/]eoscopic ,a]ial ,views4--,att5tion has already be5 call$ to ! *>act]i/ic flatness ( ! a]ial view4 ,nei!r ! picture on ! ret9a nor t on ! photographic plate af=ds any adequate idea ( hills & holl[s4 ,unless %ad[s are well def9$1 small local elevations & depressions _c be di/+ui%$ f m]e diff]5ce 9 color or m>k+4 ,ev5 9 ! pres5ce ( %ad[s x is (t5 only by close /udy t diff]5ces ( cont\r are noticeable4 ,b ) /]eoscopic views ^! features /& out 9 a /rik+ mann]4 ,tak+ our illu/rations f milit>y s\rces1 we may note ! use ( /]eoscopic pictures to detect undulations ( gr\nd 9 front ( tr5*es 7,fig4 #afa74 ,!y reveal ! hillocks1 pits1 small qu>ries1 /reams fl[+ beh9d high banks1 & o!r features :i* make ! attack h>d or easy4 ,comm&+ positions are %[n1 ! b\nd>ies ( areas expos$ to ma*9e-gun fire1 & ! defilades :]e ! attack]s may pause to re=m4 ,concrete 8pill boxes0 are locat$ 9 ! mid/ ( %ell holes ( ! same size & outl9e1 & c be diff]5tiat$ f !m4 ,railway or road embankm5ts & cuts c be detect$ & /udi$ to extraord9>y advantage 9 /]eoscopic pictures4 ,?us :at appe>s to be a m9e crat] on a level road1 easily driv5 ar\nd1 may be a gap bl[n 9 an embankm5t1 a s]i\s ob/acle inde$4 ,bridges1 obs]vation t[]s & o!r elevat$ /ructures jump into view 9 ! /]eoscope :5 (t5 !y h entirely elud$ notice 9 ! ord9>y flat picture4 ,once pres5t$ 9 relief1 cam\flag$ build+s or gun emplacem5ts1 h[ev] c>efully pa9t$1 are ridicul\sly easy to pick out4 ,illu/ration3 ,,fig4 #afa4--,typical /]eogram ( milit>y detail4 ,fuse by look+ at a di/ant object ov] ! top ( ! page1 & quickly dropp+ ! eyes to ! pr9t4 ,practical peace-"t applications ( /]eoscopic views c easily be =ese5 foll[+ ! l9es ( w> exp]i5ce4 ,su*1 = in/ance1 w\ld be ! /udy ( propos$ railway or canal r\tes4 ,a s]ies ( /]eograms w\ld obviate ! necessity ( cont\r surveys1 at lea/ until ! exact r\te 0 pick$ & con/ruction "w ready to />t4 ,ap>t f _! utilit>ian side1 h[ev]1 /]eoscopic views h v great pictorial m]it4 ,/]eoscopic pictures ( ca!drals1 public & o!r l>ge build+s1 h (t5 great beauty1 & af=d opportunities = ! /udy ( =m giv5 by no o!r k9d ( repres5tation1 %ort ( exp5sive scale models4 ,!y may v well lead 9 ! ne> future to a revival ( ! popul>ity ( ! /]eoscope4 ,impression ( ,relief ,produc$ by ,motion4--,an appe>ance ( solidity c be obta9$ 9 mov+ pictures by ! simple exp$i5t ( sl[ly mov+ ! cam]a lat]ally z ! pictures are tak54 ,z an illu/ration1 if ! mov+ picture cam]a is c>ri$ on a boat :ile /ructures on ! %ore are photograph$1 :5 ^! are project$ on ! scre5 !y appe> 9 relief1 due to ! relative motion ( =egr\nd & backgr\nd4 ,z relief ( ?is sort is n dep5d5t on ! use ( ! two eyes1 x dem&s no special view+ app>atus4 ,?is idea has be5 utiliz$ to a limit$ ext5t 9 ord9>y mov+ picture photography by introduc+ a sl[ to-&-fro motion ( ! cam]a1 b ?is c h>dly be consid]$ satisfactory1 s9ce ?is motion is s obvi\sly unnatural4 ,9 mov+ pictures made f ! airplane ! normal rapid motion ( ! po9t ( view is ideal = ! production ( ! impression ( relief 9 ! mann] j describ$4 ,= in/ance1 9 mov+ pictures ( a city made f a l[ fly+ plane1 ! skyscrap]s & spires z !y sweep pa/ /& =? f _! m sl[ly mov+ backgr\nd 9 bold & satisfy+ solidity4 ,9 fact1 su* pictures probably con/itute ! mo/ satisfactory solution yet f\nd ( ! vex+ problem ( 8/]eoscopic0 projection4 ,no bett] m$ium c be imag9$ = ! travel lectur] to introduce 8 audi5ce to a =eign city ?an to ?r[ ^u 8 scre5 a film made 9 a plane approa*+ f af> & !n circl+ ! ar*itectural l&m>ks at l[ altitudes4 ,,*apt] ,,xxix ,,! ,,int]pretation ,,( ,,a]ial ,,photographs ,oblique a]ial photographs if on a l>ge en\gh scale are ev5 easi] to int]pret ?an are ord9>y photographs tak5 f ! gr\nd1 s9ce !y practically pres]ve ! usual view1 & add to x ! ess5tials ( a plan4 ,) v]ticals1 h[ev]1 ?is is f> f ! case4 ,9 !m all natural objects pres5t an appe>ance q =eign to ! ord9>y mortal's previ\s exp]i5ce ( !m4 ,?is may be easily demon/rat$ by tak+ any a]ial view conta9+ a fair am\nt ( detail & try+ sy/ematically to id5tify ea* object4 ,a necess>y prelim9>y to do+ ?is accurately is acqua9tance ) & /udy ( ! gr\nd photograph$1 or ( simil> regions1 & ( objects ( ! same "* z ^? likely to be includ$4 ,! int]pretation ( milit>y a]ial photographs is ( su* importance1 & has become su* an art1 t x is ! function ( special dep>tm5ts ( ! intellig5ce s]vice4 ,ext5d$ c\rses 9 ! subject are n[ giv5 9 milit>y s*ools4 ,?is in/ruction mu/ cov] m ?an ! int]pretation ( a]ial photographs z su*4 ,g5]al milit>y k is ess5tial1 s t n only may photograph$ objects be recogniz$1 b ! significance ( _! appe>ance be realiz$4 ,:e!r attack or retreat is indicat$2 :e!r a long range bomb>dm5t is 9 prep>ation1 or a m]e /r5g!n+ ( local def5ces4 ,! natural difficulties ( int]pret+ a]ial views are enorm\sly increas$ by ! unfamili> nature & frequ5tly *ang$ "* ( ! milit>y /ructures1 & p>ticul>ly by ! attempts made to conceal ^! f a]ial obs]vation by selection ( surr\nd+s & by cam\flage4 ,! small scale ( ! photographs1 9 :i* a ma*9e gun %[s z a m]e p9 po9t1 adds to ! unc]ta9ty1 ) ! net result ( mak+ int]pretation a task ( m9ute /udy & d$uction wor?y ( a ,%]lock ,holmes4 ,little detail$ in=mation on int]pretation c be pr(itably writt5 9 a g5]al treatise1 p>tly because ! illu/rations available are ( a highly te*nical milit>y "*1 p>tly because orig9al photographs in/ead ( halftone reproductions are practically imp]ative = purposes ( /udy4 ,nev]!less "s g5]al in/ructions1 applicable to any problem ( int]pretation1 may be giv51 z well z a few illu/rations1 drawn f milit>y s\rces1 :i* w s]ve to %[ ! detective skill necess>y4 ,fir/ ( all x is important t ! pr9t or transp>5cy be held 9 ! "r position4 ,! %ad[s mu/ always fall t[>d ! obs]v]2 o!rwise1 reliefs w appe> z holl[s & holl[s w %[ z hills4 ,! reason = ?is is t ! body ord9>ily acts z a %ield1 prev5t+ ! =mation ( %ad[s except by light fall+ t[>d ! behold]4 ,?us 9 ,fig4 #afb ! slag heap looks l a qu>ry :5 ! %ad[s fall away f "o4 ,! necessity = prop] direction ( %ad[s is1 x may be not$1 9 conflict ) ! ord9>y conv5tion = ! ori5tation ( maps--at lea/ 9 ! nor!rn hemisph]e4 ,a city map1 made by sunlight fall+ f ! s\?1 pres5ts its %ad[s z fall+ away f ! obs]v]1 :5 x is m\nt$ ) its nor? po9t at ! top1 z is cu/om>y4 ,z a consequ5ce build+s 9 a]ial photographic mosaics ( cities occasionally look sunk5 in/ead ( /&+ out4 ,illu/ration ,wrong way4 ,%ad[s fall+ away ,"r way4 ,%ad[s fall+ t[>d f obs]v]4 obs]v]4 ,,fig4 #afb4--,! wrong way & ! "r way to hold a photograph = int]pretation4 ,illu/ration3 ,,fig4 #afc4--;,guide to int]pretation ( tr5* details4 ,! relation betwe5 ! %ape ( ! %ad[ & ! object ca/+ x mu/ be well le>n$4 ,?is is a "p ( ! tra9+ ( e ar*itectural draftsman1 b ! appe>ance ( %ad[s f above has n h]et(ore be5 a matt] ( importance4 ,! diff]5ce betwe5 high & l[ tr5*es1 betwe5 cutt+s & embankm5ts1 betwe5 %ell holes1 occupi$ or unoccupi$1 & 8pill boxes10 mu/ be detect$ l>gely f ! "* ( ! %ad[s4 ,:i* elevations & depressions are ( milit>y & :i* ( m]ely accessory nature1 :e!r ?is black dot is a ma*9e gun or a signal+ device1 :e!r t d>k spot is an active gun port or an ab&on$ "o--^! are all matt]s ( %ad[ & ( light & %ade /udy4 ,sev]al illu/rations ( ^! po9ts appe> 9 ,figs4 #afc1 #afd & #afe4 ,illu/ration3 ,,fig4 #afd4--;,guide to int]pretation ( %ell holes & o!r pits4 ,illu/ration3 ,,fig4 #afe4--;,illu/rat+ ! importance ( di/+ui%+ betwe5 objects ( simil> appe>ance b diff]5t milit>y importance4 ,%ad[s may be us$ to get exact in=mation z to directions & magnitudes4 ,if we "k ! "t ( day at :i* a picture is tak51 ! direction ( ! %ad[s w give ! po9ts ( ! compass4 ,a *>t = do+ ?is is %[n 9 ,fig4 #aff4 ,! l5g? ( a %ad[ is a measure ( ! height ( ! object ca/+ x1 & ! exact relation betwe5 ! two dim5sions is det]m9$ by ! day & h\r4 ,fig4 #afg embodies 9 *>t =m ! values ( ?is relation%ip = all times ( ! ye> & day1 :ile ,fig4 #afh %[s ! k9d ( picture 9 :i* %ad[ data c\ld be utiliz$ to great pr(it4 ,illu/ration3 ,,fig4 #aff4--,location ( true nor? f direction ( %ad[s4 ,place ! dial on ! photograph1 ! h\r l9e correspond+ to ! "t x 0 tak5 be+ po9t$ 9 ! direction ( ! %ad[s4 ,nor? lies betwe5 ! two arr[s1 ! exact direction be+ obta9$ by jo9+ ! c5t] ( ! dial to ! po9t on ! figure ( eight correspond+ to ! date on :i* ! picture 0 tak54 7,numb] on figure ( eight repres5t ! #a/ ( ! mon?47 ,m9ute *anges1 bo? 9 light & %ade & 9 position1 mu/ be wat*$ = ) great c>e4 ,naturally gr[+ foliage & ! cut bran*es us$ = cam\flage diff] 9 color progressively ) ! dry+ up ( ! leaves4 ,h5ce a m]e spot ( light] tone 9 a picture ( a =e/1 especially if ! picture is tak5 ?r\gh a deep filt]1 becomes in/ant object = suspicion4 ,! complete /udy ( any position calls = photographs ( all k9ds--v]ticals1 obliques1 & /]eos4 ,/]eoscopic views are ! wor/ foe to cam\flage4 ,a bridge pa9t$ to look l ! riv] b5ea? is labor ?r[n away if ! /]eo %[s x to be a good t5 feet above ! real riv]6 ,illu/ration3 ,,fig4 #afg4--,l5g? ( %ad[ ( object "o met] high1 at diff]5t times ( ! day & ye>1 = latitude ( ,p>is4 ,illu/ration3 ,,fig4 #afh4--;,be?une1 ,augu/1 #aiah1 illu/rative ( int]pretation by %ad[s4 ,illu/ration3 ,,fig4 #afi4--,typical tr5* photograph %[+ fir/ & second l9es1 communicat+ tr5*es1 li/5+ po/s1 ma*9e gun emplacem5ts1 & b>b$ wire4 ,a few illu/rations ( ! m ord9>y & obvi\s objects ^: detection is ! subject ( a]ial photography are %[n 9 accompany+ figures4 ,fig4 #afi pictures a typical tr5* sy/em1 ) b>b$ wire4 ,! tr5*es %[ z n>r[ ca/ellat$ l9es1 f :i* run ! zigzag l9es ( communicat+ tr5*es1 saps1 & li/5+ po/s4 ,! m9ute pockm>ks beh9d ! ma9 tr5* l9es are %ell holes & ma*9e gun pits4 ,! b>b$ wire %[s z d\ble & triple gray b&s1 intricately criss-cross$ at /rategic po9ts4 ,ano!r =m ( def5ce1 int5d$ = ! same purpose z ! b>b$ wire ( ! we/]n front1 is t furni%$ by ov]?r[n trees 9 =e/ regions4 ,fig4 #agj reveals a m\nta9 =tress surr\nd$ by a zone ( fell$ trees1 & indicates 9 /rik+ mann] ! value ( ! in=mation a s+le a]ial photograph may furni% to an attack+ =ce4 ,fig4 #abc %[s on a comp>atively l>ge scale oppos+ tr5* sy/ems 9 :i* a natural ob/acle--a riv]--sep>ates ! adv]s>ies4 ,nicks & dots indicate ma*9e guns to ! skill$ eye1 & sev]al rectangul> /ructures are reveal$ z concrete build+s :i* h surviv$ unsca!d ! %ell fire :i* has oblit]at$1 & caus$ to be rebuilt1 ne>ly e o!r elem5t ( ! tr5* sy/em4 ,illu/ration3 ,,fig4 #agj4--;,a m\nta9 =t surr\nd$ by fell$ timb]4 ,isolat$ batt]y emplacem5ts 7,fig4 #aga7 mu/ be c>efully /udi$ to le>n if !y are 9 use4 ,! *ief indication is giv5 by ! pa?s ! m5 make 9 go+ & com+2 ^! %[ z f9e light l9es1 oblit]at$ by gr[+ vegetation if long disus$4 ,ano!r indication is ! bla/ m>ks 9 front ( ! gun muzzles2 occasionally ! s5sitive plate w cat* ! actual puff ( smoke z ! gun is dis*>g$4 ,illu/ration3 ,,fig4 #aga4--,?ree /ages 9 ! life ( a batt]y4 ,railways ( v>i\s gauges %[ z ?9 l9es1 cross$ by ties1 & exhibit+ ! *>act]i/ic curves & swit*es4 ,!y are p>ticul>ly important to detect because !y naturally lead to guns or supplies ( importance4 ,ab&on$ railways f :i* ! rails & ties h be5 remov$ leave _! m>ks on ! gr\nd & mu/ be c>efully di/+ui%$ f l9es 9 actual op]ation4 ,aviation fields are easily recogniz$ by ! hang>s1 (t5 ) 8funk hole0 tr5*es alongside = ! m5 to take %elt] 9 dur+ air raids 7,fig4 #agb74 ,o!r *>act]i/ic features are ! 8,t0 :i* %[s ! direction ( ! w9d to ! return+ pilot1 & ( c\rse ! planes !mselves1 /&+ on ! gr\nd4 ,b ! field may be inactive1 & ! planes m]ely canvas dummies1 s t to pi]ce ! disguise1 all pa?s1 ruts1 & o!r indications ( activity mu/ be m9utely /udi$4 ,ov]head telegraph & telephone l9es are reveal$ :5 new by a s]ies ( light po9ts 7,fig4 #agd71 :]e ! po/s h be5 erect$ 9 ! fre% turn$ e>?4 ,lat]1 :5 ! fields ?r\gh :i* !y pass are cultivat$1 ! po/ bases %[ z isl&s left unturn$ by ! pl[4 ,9 w9t] ! wires reveal _! position by black l9es 9 ! sn[ caus$ by dripp+s4 ,buri$ cables are indicat$ :ile build+ by _! tr5*es1 & = "s "t aft]w>d by ! comp>atively /raight l9e ( di/urb$ e>?4 ,illu/ration3 ,,fig4 #agb4--;,aviation field1 %[+ hang>s1 planes1 l&+ 8,t0 & refuge tr5*4 ,j z ! detective ( classic /ory makes full use ( fre%ly fall5 sn[ to id5tify ! footpr9ts ( ! crim9al1 s does ! a]ial photograph] utilize a sn[fall to pi]ce ! enemy's attempts at deception4 ,tracks 9 ! sn[ %[ :i* tr5*es or batt]ies are 9 actual use4 ,melt+ ( ! sn[ 9 c]ta9 places may mean fires 9 dug\ts b5ea?4 ,black smudges 9 front ( tr5* walls %[ :]e guns are active4 ,guns1 wire & o!r objects1 h[ev] c>efully pa9t$ to mat* ! gray-gre5 e>?1 /& out 9 viol5t contra/ to ?is new :ite backgr\nd 7,fig4 #agc74 ,illu/ration3 ,,fig4 #agc4--,tr5*es & b>b$ wire 9 ! sn[ ( an ,alp9e ridge4 ,italian ,air ,s]vice photograph4 ,illu/ration3 ,,fig4 #agd4--;,a fully int]pret$ a]ial photograph4 ,aft] ! a]ial photograph has be5 int]pret$ ! results ( ! int]pretation mu/ be made available to ! artill]yman or ! attack+ infantryman4 ,?is may be done by leg5ds m>k$ directly on ! photograph4 ,ano!r me?od is to m\nt ov] ! photograph a ?9 tissue pap] or oilsk9 leaf1 ) ! int]pretation m>k$ on x4 ,a yet m elegant me?od consi/s 9 outl9+ all ! *ief features ( ! photograph 9 ink1 writ+ 9 ! po9ts ( importance 9 int]pretation1 & !n blea*+ out ! photograph ) potassium p]manganate solution4 ,photographic copies ( ! resultant l9e draw+ are !n m\nt$ side by side ) ! orig9al photograph4 ,fig4 #agd1 :i* %[s a fully int]pret$ photograph1 is an example ( ?is k9d ( m\nt+4 ,,*apt] ,,xxx ,,naval ,,a]ial ,,photography ,! problems ( naval a]ial photography are q diff]5t f ^? ( milit>y a]ial "w1 & on ! :ole !y are m simple4 ,at ! same "t1 photography has play$ a consid]ably less important "p 9 naval a]ial w>f>e ?an 9 l& op]ations4 ,photography z a necess>y prep>ation = attack has n figur$ 9 naval practice ne>ly s mu* z h ! record & in/ruction aspects4 ,to "s ext5t ?is is due to ! nature ( ! naval op]ations 9 ! ,great ,w>1 to "s ext5t to ! limitations ( ceil+ & cruis+ radius ( ! naval aircraft4 ,a photographic reconnaissance1 prec$+ & foll[+ a bomb>dm5t ( %ore batt]ies2 a photographic record ( ! %ips at an*or1 z at ,santiago2 a photograph ( ! =ts def5d+ a *annel1 z at ,manila2 photographs1 quickly develop$ & pr9t$1 ( an approa*+ fleet--all ^! are possibilities ( great usefulness 9 naval w>f>e betwe5 conte/ants bo? ( :om 8come out0 & c>ry ! /ruggle to ! enemy's gates4 ,b 9 ! rec5t w> ! use ( ! subm>9e1 op]ations "u cov] ( fog1 ! /riv+ = 8l[ visibility10 & ! consid]able di/ances to be trav]s$ to rea* ! enemy lairs1 h conspir$ to limit ! developm5t ( photography z a major aid to naval combat4 ,probably :5 ! :ole hi/ory ( ! conflict is told we %all le>n t ! ,zeppel9s :i* cruis$ ov] ! ,nor? ,sea1 keep+ ! ,alli$ fleet "u obs]vation1 _h a regul> r\t9e ( photographic "w4 ,9 ! ,italian zone1 :]e mu* ( ! enemy t]ritory & sev]al important naval c5t]s lay at only %ort di/ances ov] ! ,adriatic1 ! naval photographic s]vice m ne>ly rivall$ t ( ! army ?an 9 ! ,engli%1 ,fr5* & ,am]ican zone ( activity 9 ! ,*annel & ,nor? ,sea4 ,illu/ration3 ,,fig4 #age4--;,a ligh?\se1 z ! naval fli] sees x4 ,illu/ration3 ,,fig4 #agf4--;,a ?reat5$ subm>9e attack4 ,?r[+ out a smoke scre5 to protect a convoy4 ,briti% (ficial photograph4 ,! majority ( ! photographs made 9 ! ,briti% s]vice 7 obliques1 tak5 by %ort focus 7#f to #aj in*7 h&-held cam]as4 ,?is type 0 employ$ p>tly because ( difficulties to be not$ pres5tly1 9 us+ o!r =ms ( cam]as1 b m especially because su* pictures suffic$ = ! k9d ( in=mation desir$4 ,a h&-held cam]a =m$ "p ( ! outfit ( ea* fly+ boat & dirigible1 b1 unlike l& reconnaissance1 planes asc5d+ prim>ily = picture tak+ 7 unkn[n 9 _! naval s]vice4 ,usually no photographic objective 0 pr$et]m9$--photographs 7 made only if objects ( int]e/ 7 come ^u4 ,mapp+ also =m$ no "p ( ! seaplane's "w4 ,f\r plates w\ld be c>ri$1 in/ead ( z _m doz5s 9 ! l& ma*9e1 & (t5 ^! w\ld come back unexpos$4 ,!re 7 ( c\rse "s photographic flights plann$ out be=eh&1 = ! purpose ( photograph+ ligh?\ses & o!r l&m>ks ^: appe>ance f ! air %\ld be kn[n to ! naval aviator 7,fig4 #age74 ,among ! accid5tal & record types ( photograph come convoys 7,fig4 #agf71 ^: composition & arrangem5t 7 made a matt] ( record1 p>ticul>ly if any %ip 0 out ( its assign$ position4 ,photographs ( oil spots on ! sea surface1 or o!r results ( bomb dropp+1 7 necess>y evid5ce to e/abli% ! s9k+ ( a subm>9e 7,fig4 #agi74 ,pictures ( all types ( %ips fri5dly1 neutral1 & :]e possible1 enemy--7 a mu* ne$$ "p ( naval equipm5t1 9 p>ticul> pictures ( fri5dly de/roy]s & subm>9es1 :i* %\ld n be bomb$ by mi/ake4 ,= safe navigation x 0 ess5tial to h photographs ( un*>t$ wrecks 7,fig4 #aha71 ( buoys out ( place & ( %ips fail+ to return signals or o!rwise to comply ) rules4 ,! great majority ( ! pictures 7 tak5 f altitudes ( n m ?an #cjj met]s4 ,illu/ration3 ,,fig4 #agg4--,subm>9e com+ to ! surface4 ,u4 ,s4 ,naval ,air ,s]vice photograph4 ,illu/ration3 ,,fig4 #agh4--;,dropp+ dep? bombs4 ,illu/ration3 ,,fig4 #agi4--,! subm>9e de/roy$4 ,de/roy] on tell-tale oil pat*4 ,briti% (ficial photographs4 ,illu/ration3 ,,fig4 #ahj4--;,a convoy at an*or 9 port4 ,h&-held cam]as = naval "w h practically ! same design z ^? = l& "w4 ,9 view ( ! small] numb] ( pictures tak5 on naval trips1 & ! consequ5t abs5ce ( any ne$ = great spe$ 9 *ang+ plates1 ! ord9>y two-plate d>k slide has be5 f\nd satisfactory 9 ! ,engli% s]vice4 ,b ^! are mu* less conv5i5t ?an ! bag magaz9es us$ 9 ! ,u4 ,s4 ,naval h& cam]a 7,fig4 #ca74 ,! sights on ! naval h& cam]a are pref]ably ( ! rectangul>1 field indicat+ type1 especially useful 9 photograph+ ext5d$ objects su* z convoys4 ,z ! fly+ boat travels comp>atively sl[1 x is easy = ! obs]v] to /& up to take pictures1 & ! sight is conv5i5tly plac$ on top4 ,b if held out ov] ! side = v]ticals ! sight mu/ be on ! bottom4 ,rectangul> sights 9 bo? positions are provid$ 9 ! ,engli% cam]a 7,fig4 #ahf74 ,naval cam]as %\ld be immune f moi/ure1 :i* means do+ away ) all wood5 slides or grooves4 ,a praisewor?y practice is to c>ry ! cam]a 9 a wat]pro( bag4 ,illu/ration3 ,,fig4 #aha4--;,airplane photography z an aid to salvag+4 ,position ( wreck$ m]*antman twelve fa?oms d[n reveal$ by photograph f ! air4 ,photograph by ,briti% ,air ,s]vice4 ,illu/ration3 ,,fig4 #ahb4--;,a sea plane4 ,illu/ration3 ,,fig4 #ahc4--;,a fly+ boat4 ,illu/ration3 ,,fig4 #ahd4--;,a dirigible or 8blimp0--possibly ! photographic aircraft ( ! future4 ,illu/ration3 ,,fig4 #ahe4--;,engli% 8,type #ah0 h& cam]a on bracket = expos+ ?r\gh side w9d[ ( fly+ boat4 ,briti% (ficial photograph4 ,illu/ration3 ,,fig4 #ahf4--;,cam]a m\nt$ 9 bracket f =w>d cockpit ( fly+ boat4 ,briti% (ficial photograph4 ,cam]as o!r ?an ( ! h&-held =m h be5 little us$ 9 sea planes1 ow+ to ! difficulties ( in/allation4 ,! hydro-airplane1 consi/+ ( an ord9>y airplane fuselage m\nt$ on two pontoons 7,fig4 #ahb71 c c>ry ! same k9d ( photographic equipm5t z ! l& ma*9e4 ,b if x has a s+le c5tral pontoon ?is is n feasible4 ,! hydro-airplane is1 h[ev]1 l>gely sup]s$$ by ! fly+ boat 7,fig4 #ahc71 ^: fuselage1 ( boat =m1 re/s directly on ! wat]4 ,9 ?is type ( sea plane1 views tak5 v]tically d[nw>d are n easy to make4 ,9 ! l>g] fly+ boats ! hull projects out horizontally a matt] ( sev]al feet beyond ! side ( ! cockpit4 ,an ord9>y outbo>d m\nt+ is !re=e out ( ! "q4 ,! cam]a mu/ ei!r be held out at arm's l5g? or else m\nt$ on a long bracket 7,fig4 #ahf74 ,! usual place = c>ry+ ! cam]a is 9 ! front cockpit ) its magnific5t all-r\nd view4 ,obliques c1 too1 be tak5 9 great com=t f ! side w9d[s beh9d ! w+s1 z %[n 9 ,fig4 #ahe4 ,! possibility ( cutt+ a hole 9 ! bottom ( a fly+ boat to take c>e ( a v]tical cam]a is n ent]ta9$ 9 ,briti% & ,am]ican naval circles4 ,nev]!less x is ! regul> practice 9 ! ,italian s]vice1 ) _! small high ceil+$ fly+ boats4 ,9 !m a r\nd hole is cut 9 ! floor1 /opp$ ) a plug & rubb] gasket4 ,aft] ! boat rises into ! air ! hole is op5$1 & ! regulation ,italian cam]a is set securely 9 a frame on ! floor ov] ! hole 7,fig4 #ahg74 ,photographs are tak5 to ! capacity ( ! cam]a1 & if x is desir$ ano!r cam]a is put 9 its place1 till all its plates h be5 expos$1 & !n ev5 a ?ird4 ,be=e com+ d[n ! hole mu/ ( c\rse be clos$ aga94 ,slid+ doors h be5 design$ to close ?is ap]ture1 b h n prov$ suffici5tly wat]-tight1 al?\gh su* a device c\ld und\bt$ly be work$ out4 ,illu/ration3 ,,fig4 #ahg4--;,italian fly+ boat ) cam]a m\nt$ on ! floor4 ,) its space = five or m pass5g]s1 & ) its l[ spe$1 ! mod]n fly+ boat af=ds an excell5t craft = photographic "w4 ,!re is ample room = any size ( cam]a1 & = any /yle ( m\nt+1 if we assume t !re is no objection to an op5+ 9 ! bottom4 ,! l[ ceil+ ( ^! %ips1 h[ev]1 prev5ts _! use = c]ta9 =ms ( a]ial photography :i* %\ld be ( ! greate/ importance4 ,op]ations aga9/ %ore /ations--h>bors1 docks1 %ipy>ds1 %ips at an*or1 & =tifications--_c be und]tak5 = fe> ( anti-aircraft guns & ho/ile l& planes4 ,! solution ( ! problem ( c>ry+ & laun*+ fa/ high fly+ planes f %ips w imm$iately ext5d ! usefulness ( a]ial photography to coa/al "w4 ,9 ! rec5t w>1 su* ( ?is z 0 done1 along ! ,belgian coa/--! %ore batt]ies1 & ! results ( naval op]ations at ,zeebrugge & ,o/5d--0 done by l& planes f t]ritory held by ! ,allies4 ,! photographic equipm5t ( sea planes ( ! type sugge/$ w ( c\rse pres5t special problems1 b ! app>atus us$ w be apt to approximate closely to t ( ! l& planes4 ,,vii ,,! ,,future ,,( ,,a]ial ,,photography ,,*apt] ,,xxxi ,,future ,,developm5ts ,,9 ,,app>atus ,,& ,,me?ods ,prophecy is an und]tak+ t always involves risk4 ,! prophet's guess ( :at ! future w br+ =? is bas$ only on ! t5d5cies ( ! pa/1 ! mo/ urg5t ne$s ( ! pres5t1 & ! activity ( 8 imag9ation4 ,he may easily--& he usually does--entirely ov]look c]ta9 possibilities :i* may arise app>5tly f n[h]e & :i* pr(\ndly affect ! :ole tr5d ( developm5t4 ,conditions :i* dom9ate at ! pres5t "t--su* z milit>y necessity--may happily drop into ! backgr\nd & free ! sci5ce f "s ( its sev]e/ re/rictions4 ,) ?is caution1 "s future possibilities 9 app>atus & me?ods may be pres5t$ along ! l9es already us$ 9 discuss+ ! pres5t /atus ( a]ial photography4 ,l5ses4--,f ! milit>y /&po9t ! next /eps 9 l5s design w\ld be t[>d telephoto l5ses on ! "o h&1 & on ! o!r t[>d l5ses ( %ort focus & wide angle4 ,! telephoto l5ses us$ = spott+ w\ld be ( long equival5t focus--a met] & m--b ( h&y size1 t is1 n m ?an #ej c5timet]s ov] all work+ di/ance4 ,! wide angle %ort focus l5ses w\ld be design$ = l[ fly+ reconnaissance or quick mapp+ "w4 ,!y w\ld also be dem&$ = peace-"t mapp+ projects1 :]e ! l>ge/ possible am\nt ( t]ritory %\ld be cov]$ 9 a s+le flight4 ,bo? types ( l5s %\ld be pu%$ to ! extreme 9 ap]ture1 = %ort exposures & ! maximum ( work+ days w always be dem&$4 ,cam]as4--,peace-times w give ! necess>y opportunity to develop self-conta9$ & !re=e simply in/all$ cam]as4 ,!y w at ! same "t be made v completely automatic b simple to op]ate 9 spite ( _! complexity4 ,su* cam]as h1 dur+ ! w>1 be5 ! ideal ( all a]ial photograph]s1 b ! "t has be5 too %ort s9ce ! necess>y conditions h be5 und]/ood = t l5g?y developm5t "w & ^? complete s]vice te/s :i* are s necess>y to develop all automatic app>atus4 ,sev]al designs :i* are n[ be+ p]fect$ may be c\nt$ on to take u a long way t[>d ?is ideal4 ,on ! o!r h&1 t milit>y ideal :i* leaves ! cam]a op]ator ! greate/ possible fre$om = o!r activities1 is apt to be entirely rev]s$ 9 peace4 ,! cam]a op]ator c n[ be requir$ to be an exp]t1 :o w be free to *ange plates or filt]s & to e/imate exposures1 in/ead ( giv+ 8 be/ ef=ts to ! problem ( def5ce4 ,= him a simple & reliable h&-op]at$ or semi-automatic cam]a is entirely satisfactory1 & ! great exp5se ( complicat$ automatic app>atus has no long] its =m] ju/ification4 ,cam]a ,susp5sion4--,p]haps ! mo/ pleas+ prospect be=e ! a]ial photograph] z he turns f w> to peace "w is t ( hav+ planes built = & d$icat$ prim>ily to photography4 ,in/ead ( 8 cam]a be+ relegat$ to an inaccessible position1 pick$ aft] ! plane design has be5 (ficially 8lock$20 in/ead ( yield+ fir/ place to controls1 ma*9e gun & ammunition2 in/ead ( be+ jeal\sly criticis$ = ! space & weight x takes up1 ! cam]a c n[ claim space1 weight1 & location suitable = any likely a]ial photographic ne$4 ,high spe$ no long] w be vital1 & sl[] planes1 p]mitt+ long] exposures 9 inv]se ratio to _! spe$1 w be *os5 = photographic purposes4 ,a developm5t :i* is sure to intrigue _m inve/igators is ! gyroscopically controll$ cam]a4 ,?is has its *ief raison d'tre 9 precision mapp+1 ^: possibilities f ! air w und\bt$ly be int5sively /udi$ at once4 ,) ! automatically level$ cam]a w come r5ew$ att5tion to indicators ( "t1 altitude1 & direction1 ) ! ultimate goal ( produc+ a]ial negatives t %[ ^u _! face ! exact pr9t+ & arrang+ directions necess>y to put toge!r an accurate map4 ,s5sitive ,mat]ials4--,manufactur]s ( plates & films w direct ef=ts t[>d produc+ emulsions ( good contra/1 high color s5sitiv5ess & high effective spe$1 especially :5 us$ 9 conjunction ) ! filt]s necess>y = haze p5etration4 ,exposure data w be accumulat$ & exposure met]s appropriate = a]ial "w w be develop$4 ,color ,photography4--,color photography f ! air by any ( ! scre5-plate or film-pack me?ods is probably out ( ! "q because ( ! long exposures requir$4 ,! scre5-plates are unsuitable also because ( ! relatively l>ge size ( _! gra9 comp>$ to ! detail ( ! a]ial photograph4 ,ord9>y ?ree-color photography1 us+ ?ree sep>ate negatives1 is always subject on ! e>?'s surface to ! difficulty t ! ?ree negatives mu/ be expos$ f ! same po9t ( view1 ei!r 9 succession or by means ( "s optical arrangem5t :i* is co/ly f ! /&po9t ( light4 ,9 photograph+ f ! air ?is difficulty ( secur+ a s+le po9t ( view = ! ?ree photographs is abs5t4 ,?ree mat*$ cam]as1 side by side 9 ! fuselage1 h id5tical po9ts ( view z f> z objects on ! e>? bel[ are 9 "q4 ,consequ5tly1 ?ree-color negatives are entirely possible1 & inde$ w be simple to make z soon z plates ( adequate color s5sitiv5ess & spe$ are available4 ,probably ! new ,il=d pan*romatic plate has ! necess>y qualities4 ,night ,photography4--,! se>*+ eye ( photography 0 s omnipres5t 9 ! lat] /ages ( ! ,great ,w> t ext5sive troop movem5ts & o!r prep>ations _h to be c>ri$ out ei!r 9 photographically impossible wea!r or else at night4 ,! natural reply to ! utilization ( ! cov] ( night is to 8turn night into day0 by prop] artificial illum9ation4 ,at fir/ ?\ght x might well appe> t ! task ( illum9at+ a :ole l&scape adequately = airplane photography is well-nigh hopeless by any artificial means4 ,on "o h& we h ! v %ort exposures alone p]missible2 on ! o!r ! fact t ! int5sity ( daylight illum9ation is ov]:elm+ly great] ?an ^? common 9 ! mo/ extravagant =ms ( artificial illum9ation4 ,t[>d ! close ( ! w>1 h[ev]1 actual exp]im5ts made ) in/antane\s fla%es ( sev]al million c&lep[] %[$ t if prop] means 7 provid$ to insure ! fla% go+ (f ne> ! gr\nd1 & if its duration 7 made no long] ?an ab\t #a_/ej second1 int]pretable photographs 7 obta9able on ! fa/e/ plates4 ,x appe>s1 !re=e1 m]ely a matt] ( manufactur]s p]fect+ ! te*nique ( fla% production1 & ( inv5tors provid+ ! laun*+ & ignit+ devices to pu% ?is k9d ( photography to ! practical /age4 ,! a*ievem5t ( night photography _c fail to h an enorm\s effect on future tactics4 ,! te*nique ( night photography may take ei!r ( two directions4 ,on "o h& we may develop fla%es ( ! requisite int5sity to give all _! light 9 #a_/ajj second2 on ! o!r h&1 x may prove m feasible to use fla%es ( long] duration & to arrange = ! cam]a %utt] 7( ! betwe5-!-l5s type7 to be expos$ syn*ron\sly ) ! middle ( ! fla%4 ,"o way1 frequ5tly sugge/$1 to use ^! long] fla%es w\ld be to trail ! *>ge on a long wire1 ?r\gh :i* ! ignition is effect$ electrically4 ,?is is n likely to be satisfactory1 h[ev]1 = ! resi/ance ( a wire is s great t :5 ! plane flies at any practical height1 ! trail$ fla%1 if x rea*es ne> ! gr\nd1 w be =c$ to a v great di/ance beh9d4 ,probably ! be/ solution w involve accurate syn*roniz+ ( ! fuse 9 ! freely dropp$ sack ( fla% p[d] ) ! expos+ me*anism 9 ! cam]a4 ,,*apt] ,,xxxii ,,pictorial ,,& ,,te*nical ,,uses ,aside f _! elem5t ( novelty1 a]ial photographs h und\bt$ qualities ( beauty & utility4 ,! 8bird's-eye view0 has always be5 a favorite = reveal+ to ! be/ advantage ! entire =m & location ( build+s & ( o!r l>ge objects4 ,h]et(ore su* views h usually _h to be drawn by an imag9ative arti/4 ,illu/ration3 ,,fig4 #ahh4--,rheims ,ca!dral4 ,a]ial oblique views possess ! virtues bo? ( pictures & ( plans4 ,!y are de/9$ to be ext5sively us$ 9 ! /udy ( ar*itecture 7,fig4 #ahh74 ,ca!drals1 ca/les1 t[n halls1 p>ticul>ly ^? /ill 9 _! cramp$ m$ieval surr\nd+s :]e !y c nev] be se5 9 _! entirety f ! gr\nd1 come =? 9 all _! beautiful or qua9t proportions f ! airman's po9t ( vantage4 ,/]eoscopic a]ial views are de/9$ to occupy a valuable position also4 ,/]eo pr9ts ( ! fam\s build+s ( ,europe1 tak5 f ! air1 w give to ! prospective travel] or ! arm-*air t\ri/ a _m fold m accurate idea ( _! con/ruction ?an w any numb] ( m]e surface views4 ,illu/ration3 ,,fig4 #ahi4--;,a portion ( ,vi5na se5 f ! air1 dur+ a 8propag&a raid40 ,italian (ficial photograph4 ,illu/ration3 ,,fig4 #aij4--,! ,rialto bridge1 ,v5ice4 ,italian ,air ,s]vice photograph4 ,illu/ration3 ,,fig4 #aia4--;,a p>tly develop$ suburb4 ,a v]tical a]ial photograph is mo/ closely ak9 to a map1 b has advantages ov] any ord9>y surveyor's product4 ,z a guide x is inf9itely sup]ior to ! be/ draftsman's diagram1 = x provides a weal? ( detail :]eby ! travell] may def9itely locate himself4 ,at a s+le glance he notes ! objects ( int]e/ )9 8 radius ( easy travel4 ,! guide-book ( ! future w !re=e be incomplete )\t num]\s a]ial views1 bo? v]tical & oblique4 ,z an illu/ration ( ! peculi> m]it ( ! view f ! air1 consid] ! photograph ( ,vi5na made dur+ d',annunzio's 8propag&a0 bomb>dm5t4 ,or ! picture ( ! ,rialto bridge 7,fig4 #aij74 ,no ord9>y photograph f l& or wat] sugge/s ! c5tral roadway & no map %[s ! beauty ( its elevation4 ,bo? are %[n "h1 z well z an intimate view ( ! ar*$ & pill>$ c\rty>d ( ! ,fondaco de' ,t$es*i to ! "r4 ,illu/ration3 ,,fig4 #aib4--;,a sea-side resort4 ,illu/ration3 ,,fig4 #aic4--;,a ba?+ bea* se5 f ! air4 ,airplane photographs w und\bt$ly be widely us$ 9 c]ta9 fields ( adv]tis+4 ,ar*itects & real e/ate ag5ts may be expect$ to display _! w>es by ! aid ( a]ial views4 ,a well-plann$ c\ntry e/ate or golf c\rse1 or a suburban developm5t 7,fig4 #aia71 c be %[n ) a complet5ess1 bo? z to environm5t & /age ( progress :i* no o!r =m ( repres5tation c approa*4 ,a sea-side resort c n[ %[ ! ext5t & gr\p+ ( its natural & artificial amusem5t features 9 a s+le picture 7,fig4 #aib74 ,ev5 ! ext5t ( its ba?+ bea* "u wat] is reveal$ to ! a]ial photograph] 7,fig4 #aic74 ,real e/ate ag5ts c utilize a]ial photographic maps ( cities to great advantage4 ,on ^! _! prop]ties c be po9t$ out1 ) ! nature ( _! surr\nd+s %[n at a glance1 toge!r ) _! relation to transportation1 s*ools1 *ur*es1 %opp+ di/ricts1 p>ks1 or factories4 ,! future pur*as] ( lots 9 a di/ant boom t[n w no long] be satisfi$ ) a map outl9+ ! /reets ) high-s\nd+ names4 ,he w dem& an au!ntic a]ial photograph1 %[+ ! actual numb] ( h\ses "u con/ruction1 ! /reets1 gutt]s & sidewalks already laid1 ! size & plant+ ( trees4 ,illu/ration3 ,,fig4 #aid4--,mt4 ,v]non f ! air4 ,illu/ration3 ,,fig4 #aie4--;,a contra/ 9 ro(s4 ,! ,capitol reta9s its individuality1 :ile ! ,:ite ,h\se loses all "* :5 se5 f above4 ,! /udy ( l&scape g>d5+ is ano!r field = :i* ! a]ial photograph is peculi>ly fitt$4 ,a collection ( oblique pictures ( ! *teaux & palaces ( ,europe %[+ _! approa*es & gr\nds1 or ( ! hi/oric e/ates ( our own ,s\?1 7,fig4 #aid71 w be wor? m to ! prospective design] ( a c\ntry e/ate ?an maps & gr\nd pictures c ev] be4 ,closely alli$ to l&scape g>d5+ is city plann+1 = :i* ! a]ial map w be q indisp5sable4 ,! appe>ance ( a city f ! air may inde$ become a matt] ( pride to its inhabitants1 & n only ! arrangem5t ( /reets & p>ks1 b ev5 ! "* ( ! ro(s ( ! build+s1 be ! subject ( /udy 7,fig4 #aie74 ,illu/ration3 ,,fig4 #aif4--;,an aviation field "u con/ruction2 e>ly /age4 ,eng9e]s & con/ructors w dep5d m & m on prelim9>y photographic surveys z a basis = locat+ _! op]ations4 ,at ! lat] /ages ( _! "w !y w use a]ial photographs = record+ progress4 ,p]iodic photographs ( build+s 9 process ( con/ruction1 su* z are n[ made f ! gr\nd1 are mu* m illu/rative :5 made f ! air4 ,only f above is x possible to obta9 9 a s+le picture ! progress ( ! complete project1 su* z ! con/ruction ( an aviation field 7,figs4 #aif & #aig7 or ( a %ipy>d4 ,! build+ ( l>ge /ructures--bridges1 hotels1 %ips on ! /ocks--p>ticul>ly dem&s a]ial views if ! =egr\nd is n to eclipse ! c5t] ( real int]e/4 ,illu/ration3 ,,fig4 #aig4--;,an aviation field "u con/ruction2 lat] /age4 ,news ev5ts w soon call = an a]ial photographic s]vice4 ,already we are see+ newspap]s & magaz9es featur+ a]ial photographs ( ! entry into conqu]$ cities & ! p>ades ( return+ fleets4 ,accid5ts1 fires1 floods & wrecks1 ( ei!r local or national int]e/1 c be/ be repres5t$ by ?is newe/ =m ( photography4 ,illu/ration3 ,,fig4 #aih4--,! crat] ( ,vesuvius4 ,photograph by ,royal ,italian ,air ,s]vice4 ,! photograph+ ( wrecks1 fires & floods sugge/s ! importance ( a]ial views to insurance und]writ]s1 :o require ! mo/ m9ute in=mation on ! *>act]i/ics ( build+s 9 e neighborhood1 & on ! ext5t & nature ( damage done4 ,m>9e insurance companies might ) pr(it use ! airplane cam]a to help e/imate ! *ances ( salvage ( a /r&$ %ip or a vessel f\nd]$ 9 %all[ wat]s 7,fig4 #aha74 ,illu/ration3 ,,fig4 #aii4--,waves set up by a %ip--( int]e/ to ! naval ar*itect4 ,num]\s sci5tific uses = a]ial views seem likely4 ,prom95t among ^! is _! use 9 geology1 = ! /udy ( ! v>i\s =ms ( e>? sculpture4 ,pictures f ! air ( ext9ct volcanoes w give in=mation z to _! configuration t w\ld o!rwise require mon?s ( pa9/ak+ survey to obta94 ,a]ial photographs ( active volcanoes 7,fig4 #aih71 %[+ ! results ( a succession ( outbur/s--"o oblit]at+ ! o!r--w\ld prove ( ! greate/ value1 especially :5 /udi$ 9 conjunction ) o!r sci5tific data1 ! :ole mak+ a record unobta9able by any o!r means4 ,9 e>?quake regions--notably ,s\!rn ,italy & ,japan--! *ang+ coa/ l9es1 %all[s & safe h>bors1 c\ld be promptly asc]ta9$ aft] ! subsid5ce ( ea* fre% %ock1 ) a consequ5t keep+ op5 ( trade r\tes & (t5 ! sav+ ( life4 ,riv] c\rses1 glaci] =mations1 caons1 & all ! l>g] natural =mations :i* man usually sees only 9 m9ute sections1 & :i* he mu/ build up 9 8 m9d's eye or by models1 are today quickly & accurately record$ by ! cam]a 9 ! air4 ,su* =mations z coral reefs1 ^: configurations c n[ be accurately le>n$ only by labori\s surveys ( a limit$ numb]1 c\ld be /udi$ 9 quantity & ) h]et(ore unkn[n satisfaction z ! result ( a s+le exp$ition ) a %ip-c>ry+ seaplane & a]ial cam]a4 ,ano!r sci5tific field--probably "o ( _m simil> ones--lies 9 ! /udy ( ! waves set up by %ips 7,fig4 #aii74 ,^! are ( extreme importance 9 ! realm ( naval ar*itecture1 b be=e ! day ( ! airplane c\ld nev] be easily /udi$ 9 full scale4 ,,*apt] ,,xxxiii ,,exploration ,,& ,,mapp+ ,a]ial photographic mapp+ 9 w>-"t has be5 almo/ entirely conf9$ to ins]t+ new details 9 old maps4 ,= su* "w "s di/ortion or a lack ( complete in=mation on altitude & directions is n a s]i\s matt]1 because ! kn[n p]man5t outl9es s]ve z a basis4 ,fur!rmore1 9 s f> z outl9e maps are conc]n$1 z di/+ui%$ f pictorial maps1 ^! h be5 drawn on ! ord9>y scales1 & ) ! ord9>y conv5tions ( eng9e]+ map practice4 ,a]ial photography may be us$ 9 ! future 9 practically ! same way1 z an aid to ! quick record+ ( ^? m9ute details :i* w\ld ord9>ily consume an enorm\s am\nt ( labor to survey directly4 ,! region %[n 9 ,fig4 #bjj af=ds a good illu/ration4 ,a disc\rag+ am\nt ( "t & ef=t w\ld be requir$ to map ?is section ( ,virg9ia by ! usual me?ods1 :ile ! smalle/ curve ( creek & %ore is in/antly & completely record$ on a s+le photographic plate4 ,b !re are o!r possibilities1 div]g+ f ?is application bo? t[>d great] & less] requirem5ts = precision4 ,pictorial maps1 9 :i* ! actual photographs figure1 promise to be an ess5tial "p ( ! airman's equipm5t1 :e!r he be pilot or pass5g]1 mail c>ri] or sportsman4 ,)\t any pret5tion to detail$ accuracy ( location1 ^! maps w %[1 9 /rip or mosaic =m1 ! g5]al appe>ance ( ! c\ntry to be trav]s$1 ) p>ticul> ref]5ce to good l&+ fields & o!r po9ts ( int]e/ to ! aviator4 ,v]tical pictorial maps may be supplem5t$ by obliques giv+ ! view ahead1 :]eby ! pilot may direct 8 %ip4 ,?us ! ,wa%+ton monum5t z se5 by ! pilot f ,baltimore is a tru] guide ?an is ! c\ntry b5ea? him4 ,! cross+ ( m\nta9 ranges is ano!r case :]e ! oblique picture w be m useful ?an ! v]tical 7,fig4 #bja74 ,illu/ration3 ,,fig4 #bjj4--;,an a]ial photographic survey ( gr\nd difficult to cov] by ord9>y survey+ me?ods4 ,illu/ration3 ,,fig4 #bja4--,seek+ out m\nta9 passes4 ,contra/$ ) ! m]ely pictorial maps w be precision surveys4 ,:e!r x w prove practical to make ^! entirely f ! air is /ill an op5 "q4 ,x is to be assum$ t cam]as c be con/ruct$ ) l5ses hav+ negligible di/ortion ( field1 ) betwe5-!-l5s %utt]s to obviate ! di/ortions due to ! focal-plane type1 ) auxili>y devices = indicat+ compass direction1 altitude1 & incl9ation1 or ) gyroscopic m\nt+ s t an incl9ation indicator is unnecess>y4 ,! application ( a]ial photography to precision mapp+ w dep5d ^u ! p]fection :i* su* cam]as atta91 z e/imat$ by ! p]missible errors 9 ?is =m ( mapp+4 ,entire dep5d5ce on photography1 z 9 un*>t$ regions1 is likely to be work$ up to sl[ly1 beg9n+ ) a /age ( r complete triangulation ( natural or artificial po9ts--say ?ree 9 ea* con/itu5t picture--!n ?r\gh sev]al /ages ea* successively employ+ few] & few] well det]m9$ po9ts4 ,! photographic mapp+ ( "s ( our ,we/]n ,/ates w be greatly facilitat$ by ! #ajj-y>d squ>es into :i* ! l& is divid$ & already m>k$ 9 a mann] :i* %[s cle>ly 9 a]ial photographs4 ,a !oretical possibility is ! plott+ ( cont\rs f /]eo-a]ial pictures4 ,giv5 two elem5ts ( a /]eoscopic pair1 tak5 f po9ts ^: sep>ation is kn[n1 ! position ( any po9t 9 space %[n 9 ! /]eoscopic view c be det]m9$ by ! use ( ! /]eo-comp>ator4 ,?is is an in/rum5t already employ$ 9 m\nta9 photo-survey+1 :i* consi/s ess5tially ( a comp\nd /]eoscope 9 ^: eye-pieces are two po9ts movable at w s t ! relief image =m$ by _! fusion c be made to co9cide ) any *os5 "p ( ! l&scape4 ,! *ief difficulty 9 ! application ( ?is idea to a]ial "w is to fix ! base l9e4 ,?is problem may be met 9 "s cases by us+ /]eo obliques1 & gett+ ! base l9e by simultane\sly made v]tical photographs ( well survey$ t]ritory b5ea?4 ,possibly also me?ods c be develop$ by :i* photographs f two or m kn[n altitudes may furni% ! requisite data4 ,illu/ration3 ,,fig4 #bjb4--;,bus9ess section ( ,hampton1 ,virg9ia4 ,a survey made by a s+le in/antane\s exposure4 ,illu/ration3 ,,fig4 #bjc4--,mosaic map ( ! ,city ( ,wa%+ton4 ,:ite rectangle %[s portion includ$ 9 next figure4 ,illu/ration3 ,,fig4 #bjd4--,portion ( ,wa%+ton mosaic1 full size4 ,city mapp+ is a field = :i* a]ial photography is peculi>ly fitt$ 7,fig4 #bjb74 ,a complete map ( a l>ge city is a labor ( ye>s4 ,9 fact1 a mod]n city is always dang]\sly ne> to gr[+ fa/] ?an its maps4 ,an a]ial map1 on ! contr>y1 c be produc$ 9 a few h\rs4 ,p>is 0 mapp$ ) #hjj plates 9 less ?an a day's actual fly+4 ,wa%+ton 0 completely mapp$ 9 #b h\rs1 ) less ?an #bjj exposures4 ,! entire map is %[n1 on a greatly r$uc$ scale1 9 ,fig4 #bjc1 :ile ,fig4 #bjd %[s a small portion ( x 9 full size1 f :i* c be obta9$ an idea ( ! dim5sions ( ! orig9al4 ,^! maps1 :ile n accurate en\gh = ! record+ ( de$s & mortgages1 yet s]ve ! majority ( ne$s4 ,!re is inde$ no reason :y ) long focus cam]as1 giv5 sev]al accurately m>k$ po9ts1 ! photographic map ( a piece ( real e/ate %\ld n be made ) all ! accuracy ne$$1 /ill leav+ ! :ole process ( p>tial survey+ help$ out by photography an enorm\sly simpl] "o ?an ! usual me?od4 ,r\gh] types ( survey+1 9 op5 c\ntry1 (f] a mo/ promis+ opportunity4 ,railway surveys1 %[+ ! "* ( ! c\ntry3 passes ?r\gh m\nta9 ranges3 ! available timb] & o!r mat]ials ( con/ruction4 ,canal r\tes1 ) ! available s\rces ( wat] supply1 & ! be/ *oice ( c\rse to avoid deep cutt+s & aqu$ucts4 ,irrigation projects1 ) ! natural lakes1 riv] c\rses & valleys1 :i* may be damm$ to =m /orage bas9s4 ,coa/1 riv] & h>bor surveys are possible by a]ial means ) a promptness & frequ5cy :i* %\ld entirely revolutionize ! mak+ ( maps ( wat]ways4 ,%ifts 9 *annels & %all[s1 ev5 ( consid]able dep?1 /& out prom95tly 9 ! a]ial photograph4 ,! actual bottom1 if n m ?an ?ree or f\r met]s d[n--z 9 a ba?+ bea*--%[s 9 ! a]ial photograph 7,fig4 #aic71 :ile ! v>y+ surface t9ts caus$ by light reflect$ f ! bottom at f> great] dep?s are readily diff]5tiat$ by ! cam]a f ! air4 ,an in/antane\s photograph w ?us p]=m ! "w n[ done by a week's s\nd+s4 ,fig4 #bje1 tak5 ne> ,langley ,field1 %[s h[ ! a]ial photograph may be us$ to *>t natural *annels1 :ile ,fig4 #bjf %[s ! dr$g$ *annels ( ! port ( ,v5ice4 ,navigation ( su* a riv] z ! ,mississippi ) its %ift+ b>s may come to be guid$ by mon?ly or ev5 weekly a]ial photo maps4 ,illu/ration3 ,,fig4 #bje4--,%all[s & *annels reveal$ by ! a]ial photograph4 ,illu/ration3 ,,fig4 #bjf4--,v5ice f ! air1 %[+ dr$g$ *annels4 ,italian (ficial photograph4 ,illu/ration3 ,,fig4 #bjg4--;,b5gasi1 a ,nor? ,african t[n1 survey$ = ! fir/ "t f ! air4 ,italian (ficial photograph4 ,illu/ration3 ,,fig4 #bjh4--,?urnb]g on ! ,rh9e4 ,photograph by photographic section ,a4 ,e4 ,f4 ,among o!r uses = a]ial photography w be ! location ( timb]4 ,z "o illu/ration1 may be tak5 ! discov]y ( mahogany trees4 ,_! foliage at c]ta9 times ( ! ye> is ( *>act]i/ic color4 ,?is may be record$ on color s5sitive plates ) a sci5tifically *os5 filt]1 & ! cutt+ exp$ition s5t out ) ! photograph z a guide4 ,9 ?is z 9 o!r cases :]e r\gh or unexplor$ c\ntry is to be cov]$1 x is a "q :e!r ! airplane w aft] all be ! mo/ feasible craft1 on acc\nt ( its necess>ily rapid rate ( travel1 & its ne$ = kn[n l&+ fields4 ,! dirigible ( l>ge cruis+ radius1 :i* c seek its l&+ field at leisure1 is probably indicat$ = ?is k9d ( "w4 ,x may inde$1 z already h9t$1 prove to be ! *ief photographic aircraft ( ! future4 ,ar*ological surveys (f] a fasc9at+ opportunity = airplane or dirigible balloon photography to r5d] sci5tific s]vice4 ,buri$ 9 des]t s&s or ov]gr[n ) tropical vegetation ! anci5t cities ( ,asia ,m9or1 ( ,burma1 & ( ,yucatan evade discov]y1 & ev5 :5 f\nd rema9 unmapp$ = decades4 ,discov]y & mapp+ c n[ g h&-9-h&4 ,! topography ( b>b>ic or colonial t[ns & villages1 ^: importance c\ld n w>rant elaborate surveys1 b :i* %\ld nev]!less be a matt] ( record1 w be quickly & easily plott$ by photography 7,fig4 #bjg74 ,to ?is day :o kn[s h[ ! /reets run 9 ,timbuctu1 & h[1 save f ! air1 c we ev] map ! teem+ cities ( ,*9a8 ,he :o w\ld foll[ 9 ! foot/eps ( ,h>\n-al-,ras*id c ev5 n[ explore ! by-ways ( ,bagdad by ! aid ( ! ,royal ,air ,=ce photographic map6 ,,index ,ab]rations1 l5s1 #dg1 #ed ,ab]ration1 sph]ical1 #dg1 #ed *romatic1 #dh1 #ed ,acetyl5e light1 #bhd ,adv]tis+1 use ( a]ial photography 91 #cib ,a]o #a & ,a]o #b filt]s1 #bda ,airplane1 z cam]a plat=m1 #bj types (1 #bd ,air spe$1 #bg1 #cjh indicator1 #cc1 #cd ,alcohol1 use ( 9 plate dry+1 #bge use ( 9 pr9t dry+1 #bhf ,altimet]1 #cc1 #agd read+ record$ on film1 #ace1 #aga ,altitudes ( flight = photography1 #fa1 #bbd ,ana/igmatic type ( l5s1 #dg ,ap]ture1 l5s1 #ci1 #dd1 #ef1 #eg ,ar*ological survey+1 #dac ,a/igmatism1 #di1 #ej1 #ed ,auxili>ies1 cam]a1 #afc in/allation (1 #bad ,bagley cam]a1 #bhf1 #cad ,balance1 ( cam]a1 #if ( plane1 #aeg1 #bjh1 #bag ,balloons1 #ae1 #af1 #ah ,bank+1 #bg1 #cbd ,batt]ies1 /orage1 #aej1 #aef ,bay1 cam]a1 #abj1 #baj ,bell[s1 cam]a1 #fe1 #ie ,biplane1 #bd ,bla/ m>ks 9 front ( guns1 #cfc ,blea*+ out pr9t to leave int]pretation m>ks1 #cfg ,boat1 fly+1 #be1 #cgd ,b[d5 wire1 #ajc1 #ajf1 #ajh1 #aaa1 #aad1 #aaf1 #aah1 #abf1 #abi1 #acf1 #afc ,brightness1 range (1 #bba1 #bbe ,bur*ell photographic slide rule1 #cjc1 #cci ,cam]a1 airplane1 #ci1 #chd automatic1 #ah1 #dc1 #ij1 #aaf1 #abd1 #abe1 #caa ,b4 ,m41 #abj1 #bjc ,bagley1 #bhf1 #cad ,brock automatic plate1 #abf ,c type1 #dc1 #hg1 #ajc1 #aji classification (1 #dc de,maria1 #hf1 #hi1 #ajc de,ram1 #hb1 #ic1 #aba1 #abi1 #aeg1 #bje1 #bad1 #cbf ,e type1 #dc1 #hg1 #ajc1 #aji elem5ts (1 #db film1 see ,film cam]as ,folm] automatic plate1 #abf h& held1 #ie1 #cba1 #cfi ,engli%1 #ii ,g]man1 #ii ,u4 ,s4 ,air ,s]vice1 #ajj ,ica1 #ajc ,lamp]ti 7,italian71 #aab1 #baa ,l4 ,b41 #abj long focus1 #ajc1 #cja1 #cbd ,l type1 #dc1 #hb1 #id1 #ajb1 #aag1 #afb1 #baj ,m41 #ajf1 #bjc non-automatic1 #dc1 #ajb ,pis]9i & ,mond9i1 #aaa semi-automatic1 #dc1 #aaf1 #adi /]eoscopic1 #cda ,cam\flage1 filt]s = ! detection (1 #bbe1 #bdc /]eoscopic views &1 #cbi1 #ceh ,ceil+ ( plane1 #bg1 #acj ,*annels1 detection ( by photography1 #djh ,*emicals1 photographic1 #beg ,*lorhydro*9on develop]1 #bfa ,*romatism1 lat]al1 #di1 #ed ,city plann+1 use ( a]ial photography 91 #cif ,clock-"w = driv+ cam]as1 #adi1 #aee ,cl\ds1 #bbd1 #bdb ,collimator1 #ff ,color1 coeffici5t or index ( negative1 #bei filt]s1 see filt]s photography1 #che s5sitive plates1 #ae1 #agd1 #bcc1 #bcg s5sitiv5ess ( film1 #aca s5sitiz+1 me?ods (1 #bce ,coma1 #dg1 #dh ,communication1 means ( on plane1 #bif ,compass1 #cc1 #agc read+ record$ on film1 #ace1 #aga ,cone1 cam]a l5s1 #db1 #aad int]*angeable1 #ajh1 #abj ,con/ruction op]ations1 a]ial photographic records (1 #cif ,contact1 imp]fect 9 pr9t+1 #bgi1 #bhd pr9ts1 #de1 #bgi ,contacts1 electric1 on plane1 #afc ,cont\rs by /]eo a]ial photography1 #djd ,control1 di/ance1 ( cam]a1 #aaj1 #afc spe$1 ( cam]a1 #acf1 #add1 #aeg ,controls1 duplicate1 #ai1 #be1 #aie1 #bji1 #bad ( plane1 #ba1 #bf ,conv]g5ce po9t1 #ccg ,cord = adju/+ %utt] ap]ture1 #hb ,core rack developm5t1 #bga ,contra/1 9 brightness on e>?'s surface1 #bba 9 photographic emulsions1 #ae1 #bcj1 #bcf1 #beh ,c\nt]1 exposure1 on magaz9e1 #hh on release1 #afd ,cov]+ p[] ( l5s1 #dd1 #di1 #ej1 #eh ,crabb+1 #bg1 #cjh ,cradles1 cam]a1 #aie ,cross wires1 #bc ins]tion ( cam]a ?r\gh1 #db1 #baj ,curta91 auxili>y %utt]1 #hj1 #hd1 #ajf spe$ ( travel ( %utt]1 #gd uni=mity (1 #gf1 #hb1 #hd1 #hf1 #cae ,cyl9d]s1 relation betwe5 vibration & numb] (1 #ahe ,d>k slides1 d\ble1 #hg1 #ii ,daylight1 int5sity (1 #bbb ,def9ition1 l5s1 #dd ,d5sity1 ( air1 effect ( on propell]1 #aed ( photographic image1 #bbh ,develop]s1 = plates & films1 #beg1 #bfj = pap]s1 #bfb ,develop+ ma*9es1 film1 #acc1 #bgc ,ansco1 #bgc ,brock1 #bgd ,ea/man1 #bgd ,g4,e4,m41 #bgc ,developm5t1 core rack me?od (1 #bga factor1 #bbh film1 #bgb me?ods (1 #bfg1 #bfi ( pr9ts1 #bhf spe$ (1 #bcf1 #bfg tank1 #bgj "t1 #bfi ,,dh-#d plane1 #baj1 #bag1 #bif photographic1 #bac ,,dh-#i plane1 #bif ,diaframs1 to equalize illum9ation ( plate1 #gh l5s1 #dh1 #eh ,dilution coeffici5t ( develop]1 #beh ,dirigibles1 #ae1 #af1 #dac ,di/ortion1 abs5t ) betwe5-!-l5s %utt]1 #gd b>rel1 #ea due to cam]a tilt+1 #bjf1 #bhf1 #cje1 #cae 9 a]ial maps1 #cag l5s1 #ci1 #dd1 #ea1 #ed1 #ef1 #fb p9-cu%ion1 #ea produc$ by film %r9kage1 #bcg produc$ by focal plane %utt]1 #gd produc$ by glass plate 9 front ( film1 #aca ) wide angle l5ses1 #fc 8,dodg+0 9 pr9t+1 #bgi1 #cae ,doors 9 plane = cam]a to "w ?r\gh1 #bad ,dry+ ( films1 #bfg1 #bgf ( plates1 #bfg1 #bge ( pr9ts1 #bhf ,e>?1 appe>ance ( f plane1 #cj ,ea/man apron film develop+ ma*9e1 #bgd tw9 reel film develop+ ma*9e1 #bgd ,effici5cy1 propell]1 #aee %utt]1 #gj1 #gb1 #gf ,engli% a]ial photographic practice1 #de1 #df1 #bhc1 #bia1 #cdj ,,ek filt]s1 #bda ,electric1 drive = cam]as1 #aaf1 #aai1 #abc1 #ade1 #adi g5]ator op]at$ by motor1 #adf motor1 *>act]i/ics (1 #aea1 #aef motor1 s]vice1 #afc ,elevation possible to detect 9 /]eoscopic views1 #cdj ,emulsions1 photographic1 *>act]i/ics (1 #bbg ,enl>g+1 #de1 #bgi1 #bhc cam]a1 #bhc ,enl>g+ v]sus contact pr9t+1 #ei ,exhau/ion ( develop]1 #bei ,exploration1 use ( a]ial photography 91 #dja ,exposure1 data *>ts1 #bej di/ance betwe5 = mosaic maps1 #cjg di/ance betwe5 = /]eos1 #ccf e/imation (1 #bdh limitations to1 #bdg met]s1 #bea met]1 ,wynne1 #bea ( a]ial negatives1 #bdg relation betwe5 motion ( plane &1 #fh1 #ahe "u1 p]iod1 #bcj ,field1 angul>1 ( l5s1 #eg1 #cjb flatness ( l5s1 #ef ,field laboratory1 mobile1 #bfh ,film cam]as1 #dc1 #acj1 #acd ,brock1 #ach ,du*atelli]1 #aca1 #acf ,f type1 #acd1 #aga ,g4,e4,m41 #ach ,g]man1 #fd1 #gf1 #aci1 #cag ,k type1 #adb1 #bjc1 #bad ,film1 celluloid1 #acj back$1 #acc *ang+ 9 ! air1 #acg1 #add color s5sitiv5ess (1 #bcg cut1 #bge1 #bgh developm5t (1 #acj1 #bgb dry+1 #aca1 #bgf means = hold+ flat1 #acj1 #aca relative p]=mance ( comp>$ to plates1 #bcg satisfactory k9ds = a]ial "w1 #bch %r9kage1 #bcg ,filt]s1 #ae1 #eh1 #ajf1 #agd1 #bbd1 #bcc1 #bci1 #bda1 #bdc effects secur$ by use (1 #bda ,filt]s1 gelat91 #bdd glass1 #bde hold]s =1 #fg1 #ajf1 #bbd ratio1 #bdj ,fix+ ba?1 #bfb ,flaps1 auxili>y to %utt]1 #hj1 #hd1 #he1 #ih1 #ii1 #aja1 #aai to protect l5s1 #bad ,fla% lights1 #ah1 #chf ,fly+ boat1 #cgd ,focal l5g?1 relation%ip ( l5s *>act]i/ics to1 #ee1 #eg requirem5ts =1 #ci1 #db1 #eh1 #fa1 #ajc ,focal plane1 #ej %utt]1 #gj1 #ga di/ortion by1 #gd p]=mance (1 #hf types & repres5tative1 #hj ,focus1 dep? (1 #dd effect ( temp]ature on1 #da1 #fe fix$1 9 a]ial cam]as1 #dj gr\nd & air1 #fe ,focuss+1 automatic1 #bhd by p>allax1 #fe1 #ff ,fog1 atmosph]ic1 #bbd photographic1 #bcg1 #beh ,fr5* a]ial photographic practice1 #de1 #df1 #bhc ,friction disc spe$ control1 #acf1 #aei1 #afj ,fuselage1 #ba1 #hg %ape & size dep5d+ on type ( eng9e1 #bc ,future ( a]ial photography1 #chc ,g]man a]ial photographic practice1 #fc1 #ajc1 #bji ,glass1 optical1 us$ 9 l5ses1 #dd ,gloves1 h&l+ app>atus ?r\gh1 #da1 #hi ,gov]nor = cam]a spe$1 #aei ,graphite1 use ( to prev5t /atic dis*>ge1 #acd ,gravity1 action ( 9 a]ial cam]as1 #da1 #aab1 #aae1 #aai c5t] (1 %\ld n *ange 9 cam]as1 #abe1 #bjg *ange ( c5t] (1 9 magaz9es1 #ib1 #aab dep5d$ on 9 magaz9es1 #hh h&les be/ at c5t] (1 #if pseudo1 9 mov+ vehicle1 #ahh support at c5t] (1 #ahb1 #bjc ,gr\nd spe$1 #bg1 #cjg indicator1 #caa ,guide-books1 illu/ration (1 #ae1 #cib ,guides = ins]t+ magaz9es1 #da ,gyroscope1 #ahi ,gyroscopically controll$ in/rum5ts1 #bi1 #agd1 #aib1 #cab ,gyroscopic erector1 #ahh m\nt+ ( cam]a1 #ahg /abiliz]1 ,gray1 #aij ,h>d5]1 acid1 #bfb ,h& op]ation ( de,ram cam]a1 #aba1 #abe1 #abi ,haze1 #ae1 #cj1 #bbc1 #bcc1 #bci ,head resi/ance & weight1 equival5t1 #aef ,heat1 effect ( on plate s5sitiv5ess1 #age1 #bcb ,heat]1 electric1 9 cam]a1 #adb1 #agd1 #bcb ,horizon1 photography ( to indicate incl9ation1 #agd position (1 #cj ,hurt] & ,driffield s5sitometric curve1 #bbg ,illum9ation ( field by l5s1 #ej1 #ed1 #ef1 #eg ,image ( po9t s\rce1 size (1 #di1 #ed1 #ef size ( 9 relation to focal l5g?1 #ei ,incid5ce1 angle ( assum$ by plane at high altitudes1 #bjf ,incl9omet]1 #cc1 #ce1 #aga1 #agc ,indicators1 di/ance1 #afc1 #bie ,in]tia1 #bbi1 #beg ,in/allation1 cam]a1 #bd1 #bjh ,in/ructions1 op]at+1 to be plac$ on app>atus1 #db ,in/rum5ts1 airplane1 #cj ,in/rum5t bo>d1 #cj photograph+1 #agj ,int5sification ( a]ial negatives1 #bfb ,int5sity ( daylight1 #bbb ,int]pretation ( a]ial photographs1 #ag1 #dj1 #cea ,int]val betwe5 exposures1 #dj1 #aeh1 #cje1 #cjg = /]eoscopic pictures1 #ccd1 #cch me?ods ( regulat+1 #abd ,iso*romatic plates1 #bcc ,italian photographic practice1 #abb1 #cgg ,jamm+ ( cam]as 9 op]ation1 #aai1 #abj ,k#a & ,k#b filt]s1 #bci ,keep+ p[] ( develop]1 #bei ,kites1 #ae1 #af1 #ah ,laboratory1 mobile photographic1 #bfi ,l&scape g>d5+1 use ( a]ial photography 91 #cie ,latitude ( plates1 #bbi ,l5s1 #db1 #ci1 #dd1 #chc ap]ture1 #ci *>act]i/ics1 #df m\nts1 #fe suitable = a]ial photography1 #fb symmetrical1 #eb telephoto1 #fa te/+ & tol]ances1 #eb unsymmetrical1 #eb wide angle1 #fb ,levels1 _s1 on cam]a1 #ie ,light1 di/ribution ( 9 a]ial view1 #bba trail me?od ( te/+ cam]a m\nt+s1 #ahc ,loop1 c5trifugal =ce 91 #bi ,ma*9e gun r+ z cam]a m\nt1 #cba ,magaz9es1 #hg bag1 #hh1 #aja ,belli5i1 #ib ,*assel1 #ib de,maria1 #hi1 #ih ,ernemann1 #hi ,folm]1 #ij ,f\rnieux1 #ib ,jacquel91 #ib ,pis]9i & ,mond9i1 #ij ,ruttan1 #ib ,magaz9e racks1 #id in/allation (1 #bag ,mapp+1 #fd1 #ace1 #ahe1 #ahf1 #cjd1 #dja precision1 #cag1 #djd ,maps1 mosaic1 #ag1 #ci1 #fd1 #cad sket*1 #cad ,m>k+ ( negatives1 #bgh ,metol-hydro*9on develop]1 #bfa ,mirrors = oblique photography1 #cbd1 #cbf ,monoplane1 #bd ,motions ( cam]a1 #agi ,motive p[] = a]ial cam]as1 #ade ,m\nt+1 cam]a1 #ajb1 #ajc1 #agi1 #ahc #chd bell-crank1 #abj1 #aih1 #bjc ,brock1 #aci1 #bjg c5t] ( gravity1 #bje floor1 #aie ,g4 ,e4 ,m41 #ach1 #bjg ,italian1 #bjg outbo>d1 #aid p>allel motion1 #aih p5dul>1 #ahe t5nis ball1 #aif ,m\nt+1 cam]a1 turret1 #cab ( pr9ts1 #caf ( /]eograms1 #cdf ,movem5t1 ( film dur+ exposure1 #ge1 #adb ( image1 p]missible1 #fh ,mov+ pictures f plane1 #cej ,mud spla%+ on cam]a1 #bad ,naval a]ial photography1 #cfh ,negative l5s sight1 #afh1 #bii1 #cje ,night photography1 #chf ,numb]+ devices 9 cam]as1 #afi ,oblique views1 #ci1 #cbj angles at :i* tak51 #dj1 #cba exposures =1 #fi filt]s =1 #bdb use ( h& cam]as =1 #ie ,obs]v]1 function ( 9 a]ial photography1 #bia1 #bie1 #cjd ,oil spray f motor1 #bad ,opacity1 #bbh ,op5+ = cam]a1 #baa ,opposite directions1 %utt] to move alt]nately 91 #gf1 #aci ,or?o*romatic plates1 #bcc ,ov]laps1 = mapp+1 #cjg = /]eoscopic views1 #dj on a turn1 #fd1 #aci ,pan*romatic emulsions1 #bcc plates1 #di1 #bch ,panoramic views1 #cba ,p>allax me?od ( focuss+1 #fe1 #ff ,p>allel1 fly+ 91 #cjh ,photographic planes1 special1 #bac ,pilot1 function (1 9 a]ial photography1 #bia1 #bie ,p9po9ts1 #ci1 #bia ,pi/ol grip = h& cam]as1 #ie1 #if ,plate hold]s1 #hg ,plates1 ba!d1 #bce behavior ( comp>$ to film1 #bcg color s5sitive1 #bcc iso- & or?o-*romatic1 #bcc pan*romatic1 #bcc satisfactory k9ds = a]ial "w1 #bch self scre5+1 #bde %ape (1 #fc size (1 #dc1 #fb ,plumb l9e1 behavior 9 bank+ plane1 #bh ,ply-wood v5e] con/ruction1 #bc1 #baa ,positype pap]1 #bch ,potassium c>bonate = dry+ plates1 #bgf ,p[] requir$ to drive cam]as1 #abe ,pressure1 ( %utt] curta91 #aca plate1 = hold+ film flat1 #aca1 #ada ,pr9t+1 #bgi contact1 #bgi ma*9es1 #bgi m$ia1 #beb ,pr9ts1 pap]1 #bec developm5t (1 #bhf ,prisms = oblique photography1 #cbd1 #cbf ,propell]1 *>act]i/ics1 #aeb con/ant spe$1 #abi1 #aei drive = cam]as1 #ajb1 #aaf1 #aai1 #ace1 #acf1 #add1 #aeg1 #aeh position (1 #abj v>iable spe$1 #aei ,pump1 = produc+ suction on film1 #acb ,pun* m>ks on film1 #add1 #bgb ,pyro develop]1 #bfa ,racks1 negative1 #bga ,real e/ate1 a]ial mapp+ (1 #cic ,rectify+1 #bhf1 #cje cam]a1 #cad ,r$uction ( a]ial negatives1 #bfb ,release1 %utt]1 #if1 #ii duplicate1 = pilot1 #afd ,release1 %utt]1 "t controll$1 #abd ,relief1 crit]ion = correct1 #cce1 #cdd exagg]at$1 #ccg impression (1 produc$ by motion1 #cdi ,resolv+ p[] ( plates1 #ei1 #bce1 #bfj ,ri*>d /]eo pr9t+ frame1 #bhc1 #cdh ,r9s+ ( plates1 #bei ,rubb]1 sponge1 use ( 9 cam]a m\nt+s1 #aie1 #bjc ,safe lights1 photographic1 #bfi ,safety cat* on cam]a m\nt+1 #bjc device on cam]a driv+ me*anism1 #afb ,salvag+ ( %ips1 a]ial photography &1 #cii ,seaplane1 #be1 #cgd ,self scre5+ plates1 #bde ,semaphore signall+ 9 plane1 #big ,semp]focal enl>g+ cam]a1 #bhd ,s5sitiz$ mat]ials1 requirem5ts =1 #bbe ,s5sitometry1 #bbg ( pap]s1 #bec ,%ad[s1 compass directions f1 #cef prop] direction =1 9 exam9+ pr9ts1 #ceb ,%aft1 flexible1 #aai1 #abc1 #adb1 #afa ,%ea?s1 plate1 #hg1 #hh1 #ic1 #abf1 #agj ,%r9kage1 film1 #bcg1 #cag pap]1 #bhe1 #cae1 #cag ,%utt]1 #db1 #fh betwe5-!-l5s1 #eh1 #gj1 #aab1 #aae1 #caf1 #chg effici5cy1 #gj1 #gb1 #gf focal plane1 #gj1 #ga1 #gc focal plane1 d\ble = /]eo "w1 #cda1 #cde focal plane1 mov+ alt]nately 9 opposite directions1 #gf focal plane1 types (1 #hj ,%utt]1 ,folm]1 #hj ,ica1 #ha ,klopcic1 #gh1 #hd1 #ih release1 #if1 #ii1 #abd spe$1 #ci1 #dj1 #eh1 #gj1 #bdi te/+1 #gf te/+ app>atus1 #gg ,sights1 #afd1 #aff1 #bif1 #cja1 #cbg adju/able = angle ( incid5ce ( plane1 #afi atta*$ to plane1 #afg negative l5s1 #afh1 #bii1 #cje rectangul>1 #ih1 #afg1 #cgc /]eoscopic1 #cch to indicate size ( field1 #aff1 #cgc tube1 #aja1 #aff ,s+le-seat]s1 c>ry+ cam]as 91 #aad1 #baa ,slide rule1 photographic1 #cjc1 #cci ,sol5oid1 #aea1 #afc ,s\nd1 n to be us$ = indication 9 plane1 #afd ,spac+ ( pictures 9 film cam]a1 #add ,speak+ tubes on plane1 #bif ,spe$1 ( developm5t1 #bcf1 #bfg ( plates1 #bbh1 #bcf crit]ia (1 #bcj effect ( temp]ature on1 #age1 #bcb v>iable1 control ( cam]a1 #add1 #aea ,spott+1 #fd1 #abe1 #bia ,spr+ motors1 #adi1 #aee ,spr+s1 use ( 9 a]ial cam]as1 #da 9 magaz9es1 #hh ,/abiliz$ cam]a1 #ie1 #ahg ,/atic electric *>ges on film1 #aca1 #acc ,/]eo-comp>ator1 #djd ,/]eo-oblique views1 #aae1 #cba1 #cdc ,/]eoscopes1 #cca ,/]eo pr9t+1 #bhc ,/]eoscopic cam]as1 #cda1 #cdd effect1 abs5ce ( at fly+ heights1 #cj1 #ccd ,/]eoscopic photography1 #cbi m\nt+1 #cdf pictures1 fusion ( )\t in/rum5ts1 #ccj1 #cdc sights1 #cch views1 #ci1 #dj1 #fd uses =1 #cdh vision1 pr9ciples (1 #cbi ,/op-wat* atta*$ to %utt] release1 #caj ,/rap1 on h& cam]a1 to g ar\nd obs]v]'s neck1 #ii on plate magaz9e1 #hg to g ov] h&1 on h& cam]a1 #ajj ,/ream l9es1 #bf l9$ hood1 #bad ,suction = hold+ film flat1 #aca1 #acb1 #adb advantages ( cont9u\s & int]mitt5t1 #acb ,survey+ by a]ial photography1 #dja ,tank developm5t1 #bgj ,te>+ edges ( pr9ts1 #cag ,telephones on planes1 #bif ,telephoto l5s1 #fa ,temp]ature1 coeffici5t ( developm5t1 #beh effect ( on focus1 #da effect ( on me*anical function+1 #da1 #ajb1 #abe effect ( on plate spe$1 #bcb limits ( developm5t1 #beh ,te/ *>t1 l5s1 #eb ,?re%old value1 #bcj ,?ru/1 propell]1 #aeb ,timb]1 location ( by a]ial photography1 #dac ,tone r5d]+1 correct1 #bbf1 #bcj1 #bci ,t\*1 s5se (1 n dep5dable 9 plane1 #da1 #abe1 #afd ,trail]1 photographic truck &1 #bfh ,transmission ( p[] to cam]a1 #afa ,transp>5cies1 #beb1 #ccj ,transp>5cy1 #bbg ,trays1 cam]a1 #aie ,tri-color ratio1 #bce ,triplane1 #bd ,tun+ =k1 us$ 9 %utt] te/]1 #gi ,turb9e1 w9d1 = driv+ cam]a1 #aaf1 #abg1 #add1 #adg1 #aeh ,uni=mity ( curta9 spe$ 9 focal plane %utt]1 #gf1 #hb1 #hd1 #hf1 #cae ,unit sy/em ( cam]a con/ruction1 #db ,uprights1 cam]a1 9 plane1 #bji ,uses = a]ial photography1 #chh ,velocity con/ant1 #beh ,v5e] con/ruction1 #bc1 #bji1 #baa ,v5turi tube1 #acb1 #adb1 #add ,vibration1 #af1 #ah1 #bf1 #dj1 #da1 #eh1 #ajb1 #agi ,volcanoes1 photography (1 #ae1 #cii ,wat] = mix+ *emicals1 #bfb ,watk9s factor1 #beh ,weight & head resi/ance1 equival5ce1 #aef ( film comp>$ to plates1 #aja1 #acj ( de,ram cam]a1 #abc ( h& cam]as1 #if ( ,k type cam]a1 #add ( ,k film roll1 #add ( ,l type cam]a1 #aag ( ,m type cam]a1 #aji ( /orage batt]ies1 #aeg ,w9d1 fly+ aga9/1 #fh1 #cjh motor1 #adf ,w9d[s 9 side ( plane1 #bad1 #cbh ,wire1 b>b$1 appe>ance ( 9 a]ial photograph1 #cfj 99 99 99 99 99 99 ,transcrib]'s note3 #a4 ,sil5tly correct$ typographical errors4 #b4 ,reta9$ ana*roni/ic & non-/&>d spell+s z pr9t$4