,transcrib] ,note ,text emphasis d5ot$ z ,italics & ,bold4 ,:ole & fractional p>ts ( numb]s z #abc-d_/e & "s fractions z #a_/ej?4 ,a ,,manual ,,( ,,photographic ,,*emi/ry4 ,a ,,manual ,,( ,,photographic ,,*emi/ry1 ,,includ+ ,,! ,,practice ,,( ,,! ,,collodion ,,process4 ,by ,t4 ,,fr$]ick ,,h>dwi*1 ,,lectur] ,,on ,,photography ,,9 ,,k+',s ,,college1 ,,london2 ,,late ,,demon/rator ,,( ,,*emi/ry ,,9 ,,k+',s ,,college4 ,f\r? ,edition4 ,illu/ration ,,london3 ,,john ,,*ur*ill1 ,,new ,,burl+ton ,,/reet4 ,,mdccclvii4 ,! ,au?or res]ves to himself ! "r ( translat+ ?is ,edition4 ,,pr9t$ ,,by ,,john ,,edw>d ,,taylor1 ,,little ,,que5 ,,/reet1 ,,l9coln',s ,,inn ,,fields4 ,,preface ,,to ,,! ,,?ird ,,edition4 ,illu/ration ,x is a s\rce ( mu*1 gratification to ! ,au?or to f9d himself call$ ^u to prep>e a ,?ird ,edition ( 8 ,manual 9 less ?an f\rte5 mon?s f ! date ( its fir/ publication4 ,no great] pro( c\ld h be5 af=d$ ( ! rapid advance :i* ! ,photographic ,art is n[ mak+ 9 ?is c\ntry4 ,on once m ent]+ ^u ! task ( revision1 ! ,writ] has be5 l$ to reflect 9 :at way ! utility ( ! ,"w may be promot$2 & f num]\s inquiries he believes t ?is result w be/ be atta9$ by c>efully omitt+ ev]y?+ :i* does n possess practical z well z sci5tific int]e/4 ,! majority ( ,photograph]s look to ! ,art to furni% !m ) amusem5t z well z in/ruction1 & !y are det]r$ f ent]+ ^u a /udy :i* seems to involve a great am\nt ( te*nical detail3 ^! rem>ks h[ev] are n int5d$ to disc\rage a habit ( p]sev]ance & c>eful obs]vation1 b simply to di/+ui% betwe5 ! ess5tial & ! non-ess5tial 9 ! !ory ( ! subject4 ,! pres5t ,edition diff]s 9 _m important p>ticul>s f ^? :i* h prec$$ x4 ,x has und]gone a fre% arrangem5t ?r\gh\t4 ,9 "s p>ts x is cond5s$1 9 o!rs enl>g$4 ,! ,*apt]s on ,photographic ,pr9t+ are entirely re-writt51 & include ! :ole ( ! ,au?or's inve/igations1 z publi%$ 9 ! ,society's ,j\rnal4 ,! m9ute directions giv5 9 ?is "p ( ! ,"w w %[ h[ mu* success 9 ,photography is ?\ght to dep5d ^u a c>eful att5tion to m9or p>ticul>s4 ,ano!r po9t :i* has be5 kept 9 view1 is to recomm5d1 z f> z possible1 ! employm5t ( *emical ag5ts :i* are us$ 9 m$ic9e & v5d$ by all druggi/s ?r\gh\t ! unit$ k+dom4 ,x is (t5 an advantage to ! ,amateur to be able to pur*ase 8 mat]ials ne> at h&2 &1 if ! common impurities ( ! comm]cial articles are po9t$ out1 & directions giv5 = _! removal1 ! ',london ,ph>macopia' w be f\nd to include almo/ all ! *emicals necess>y = ! practice ( ! ,art4 ,great additions h be5 made to ! ,index ( ! pres5t ,edition1 :i* is n[ s complete t a ref]5ce to x w at once po9t out ! mo/ important facts relat+ to ea* subject1 & ! diff]5t p>ts ( ! ,"w at :i* !y are describ$4 ,9 conclusion1 a hope is express$ t ?is ',manual ( ,photographic ,*emi/ry' may be f\nd to be a complete & tru/wor?y guide on e po9t connect$ ) ! !ory & practice ( ! ,collodion process4 ,london1 ,june #bnd1 #ahef4 ,,preface ,,to ,,! ,,f\r? ,,edition4 ,illu/ration ,! ,au?or has endeav\r$ to keep pace ) ! improvem5ts :i* are daily be+ introduc$ 9 ! sci5ce & art ( ,photography4 ,9 ! pres5t ,edition alt]ations h be5 made 9 ! /yle & g5]al arrangem5t ( ! "w1 & additional matt] has be5 ins]t$4 ,s9ce ! publication ( ! ,?ird ,edition1 a s]ies ( exp]im5ts h be5 made on ! manufacture ( ,collodion1 ! results ( :i* h ?r[n fur!r light ^u ! conditions affect+ ! s5sitiv5ess ( ! excit$ film1 & h enabl$ ! writ] to introduce an organic sub/ance1 ,glycyrrhiz9e1 :i* w be f\nd ( s]vice 9 mak+ ,photographic copies ( ,engrav+s & simil> works ( ,art4 ,dr4 ,norris1 ( ,birm+ham1 has )9 ! la/ few mon?s communicat$ a pap] on dry ,collodion1 :i* places ! !ory ( t subject ^u a bett] foot+ ?an be=e4 ,! ,oxymel pres]vative process is n[ also ?or\ghly und]/ood1 & may be consid]$ c]ta94 ,9 addition to ! above1 ! ,album9iz$ ,collodion ( ,m4 ,taup5ot1 :i* exp]i5ce proves to be "o ( ! be/ dry processes at pres5t kn[n1 is includ$ 9 ?is ,edition4 ,k+'s ,college1 ,london1 ,april #f?1 #aheg4 ,,errata4 ,page #bd1 l9e #e1 = conditions read condition4 ,page #aae1 l9e #cb1 = ,iodide read ,iod9e4 ,page #aid1 l9e #ae1 = p4 #hh read p4 #ahh4 ,transcrib] ,note--,corrections h be5 appli$ ,,cont5ts4 ,,"p ,i4 ,,! ,,sci5ce ,,( ,,photography4 ,page ,introduction #a ,,*apt] ,i4 ,hi/orical ,sket* ( ,photography #f ,,*apt] ,,ii4 ,,! ,,salts ,,( ,,silv] ,,employ$ ,,9 ,,photography4 ,section ,i4--,! ,*emi/ry ( ! ,salts ( ,silv]4--,! prep>ation & prop]ties ( ! ,nitrate ( ,silv]--( ! ,*loride1 ,bromide1 & ,iodide ( ,silv]4--,! ,*emi/ry ( ! ,oxides ( ,silv] #ab ,section ,,ii4--,! ,photographic ,prop]ties ( ! ,salts ( ,silv]4--,! action ( ,light ^u ,nitrate ( ,silv]--^u ,*loride1 ,bromide1 & ,iodide ( ,silv]4--,! black5+ ( ,*loride ( ,silv] expla9$4--,simple exp]im5ts ) s5sitive ,photographic ,pap] #ah ,,*apt] ,,iii4 ,,on ,,! ,,developm5t ,,( ,,an ,,invisible ,,image4 ,simple exp]im5ts illu/rat+ ! process #be ,section ,i4--,*emi/ry ( ! ,sub/ances1 employ$ z ,develop]s4--,developm5t %[n to be a process ( r$uction4--,! *emi/ry ( ! pr9cipal r$uc+ ag5ts1 ,gallic ,acid1 ,pyrogallic ,acid1 & ! ,protosalts ( ,iron #bf ,section ,,ii4--,! ,r$uction ( ,salts ( ,silv] by ,develop+ ,ag5ts4--,r$uction ( ,oxide ( ,silv]--( ,nitrate & ,acetate ( ,silv]4--,v>i$ appe>ance ( ,metallic ,silv] :5 f9ely divid$4--,! r$uction ( ! ,iodide & o!r ,salts ( ,silv] conta9+ no ,oxyg5 #cj ,section ,,iii4--,hypo!sis on ! ,=mation & ,developm5t ( ! ,lat5t ,image4--,explanation ( ! t]ms "u- & ov]-exposure4--,diagram ( ,molecul> *ange4--,mos]'s exp]im5ts on developm5t4--,curi\s p]v]sions ( developm5t #cd ,,*apt] ,,iv4 ,,on ,,fix+ ! ,,photographic ,,image4 ,*emi/ry ( ! v>i\s sub/ances :i* may be employ$ z ,fix+ ,ag5ts4--,ammonia1 ,alkal9e ,*lorides1 ,bromides1 & ,iodides4--,hyposulphite ( ,soda4--,cyanide ( ,potassium #da ,,*apt] ,v4 ,,on ,,! ,,nature ,,& ,,prop]ties ,,( ,,light4 ,section ,i4--,! comp\nd ,nature ( ,light4--,its decomposition into elem5t>y col\r$ rays4--,division ( ^! rays into ,lum9\s1 ,heat-produc+1 & ,*emical ,rays #df ,section ,,ii4--,! ,refraction ( ,light4--,ph5om5a ( simple refraction by p>allel & incl9$ surfaces4--,refraction f curv$ surfaces4--,! v>i\s =ms ( ,l5ses4--,! ,foci ( ,l5ses4--,=mation ( a ,lum9\s ,image by a ,l5s #di ,section ,,iii4--,! ,photographic ,cam]a4--,its simple/ =m4--,! field ( ! ,cam]a4--,*romatic ab]ration4--,sph]ical ab]ration4--,! use ( ,/ops4--,! d\ble1 or ,portrait comb9ation ( ,l5ses4--,v>iation betwe5 ! ,visual & ,*emical ,foci 9 ,l5ses #ed ,section ,,iv4--,! ,photographic ,action ( ,col\r$ ,light4--,diagram ( ,*emical ,spectrum4--,illu/rative exp]im5ts4--,sup]ior s5sibility ( ,bromide ( ,silv] to col\r$ light4--,mode 9 :i* d>k-col\r$ objects are ,photograph$ #fj ,section ,v4--,on ,b9ocul> ,vision & ! ,/]eoscope4--,ph5om5a ( ,b9ocul> ,vision4--,!ory ( ! ,/]eoscope4--,:eat/one's reflect+ ,/]eoscope4--,brew/]'s ,/]eoscope4--,rules = tak+ ,/]eoscopic pictures #ff ,,*apt] ,,vi4 ,,! ,,photographic ,,prop]ties ,,( ,,iodide ,,( ,,silv] ,,^u ,,collodion4 ,section ,i4--,collodion4--,pyroxyl9e--its v>ieties--its *emical composition4--,means ( obta9+ ,nitro-,sulphuric ,acid ( ! prop] /r5g?4--,solv5ts = ,pyroxyl9e4--,v>iation ( physical prop]ties 9 diff]5t samples ( ,collodion4--,! *anges :i* ,iodiz$ ,collodion und]goes by keep+ #ge ,section ,,ii4--,! ,*emi/ry ( ! ,nitrate ,ba?4--,its solv5t action on ,iodide ( ,silv]4--,acidity & ,alkal9ity ( ! ,nitrate ,ba?4--,=mation ( ,acetate ( ,silv] 9 ! ,ba?4--,! sub/ances :i* decompose ! ,ba?4--,*anges 9 ! ,nitrate ,ba? by use #hf ,section ,,iii4--,! ,conditions :i* influ5ce ! ,=mation & ,developm5t ( ! ,lat5t ,image4--,causes :i* increase or dim9i% ! s5sitiv5ess ( ! film to ,light4--,conditions :i* ha/5 or ret>d developm5t #ia ,section ,,iv4--,on c]ta9 irregul>ities 9 ! ,develop+ ,process4--,effect ( p>ticul> /ates ( ! ,ba?1 & ( ! ,collodion1 9 produc+ cl\d+ ( ! ,image1 & ( acids 9 obviat+ x #ajc ,,*apt] ,,vii4 ,,on ,,positive ,,& ,,negative ,,collodion ,,photographs4 ,def9ition ( ! t]ms ,positive & ,negative4--,! same ,photograph (t5 capable ( repres5t+ bo? v>ieties #ajf ,section ,i4--,on ,collodion ,positives4--,! ,collodion & ,nitrate ,ba? be/ suit$ = ,positives4--,peculi>ities ( ,pyrogallic ,acid1 & ! ,protosalts ( ,iron employ$ to develope ,collodion ,positives4--,! col\r ( ,positives affect$ by ! l5g? ( exposure to light4--,a ,process = :it5+ ,glass ,positives by means ( ,bi*loride ( ,m]cury #ajh ,section ,,ii4--,on ,collodion ,negatives4--,! ,collodion & ,nitrate ,ba? be/ adapt$ = ,negatives4--,use ( ,glycyrrhiz9e to increase ! int5sity4--,develop+ solutions = ,negatives4--,conv]sion ( f9i%$ ,positives into ,negatives #aac ,,*apt] ,,viii4 ,,on ,,! ,,!ory ,,( ,,positive ,,pr9t+4 ,section ,i4--,! ,prep>ation ( ! ,s5sitive ,pap]4--,its d>k5+ by light4--,! conditions :i* affect its s5sitiv5ess & ! vig\r ( ! ,image4--,! col\r ( ! pr9t influ5c$ by ! prep>ation ( ! pap] #aba ,section ,,ii4--,! ,processes = ,fix+ & ,ton+ ! ,pro(4--,conditions ( a prop] fix+4--,! ,salts ( ,gold us$ z ton+ ag5ts4--,! prop]ties ( ! s+le fix+ & ton+ ,ba?1 ) ! conditions :i* affect its action #abh ,section ,,iii4--,! ,au?or's ,photographic ,rese>*es4--,! *emical composition ( ! ,photographic ,image4--,! v>i\s ag5cies de/ructive to ,photographs4--,! action ( damp air ^u ,positive ,pr9ts4--,! *ange 9 prop]ties ( ! fix+ ,ba? by con/ant use #adj ,section ,,iv4--,! ,fad+ ( ,photographic ,pr9ts4--,! causes :i* produce x4--,! comp>ative p]man5cy ( ,pr9ts4--,! mode ( te/+ p]man5cy #afj ,,*apt] ,,ix4 ,,on ,,! ,,dagu]reotype ,,& ,,talbotype ,,processes4 ,section ,i4--,! ,dagu]reotype4--,! nature ( ! s5sitive film4--,developm5t ( ! ,lat5t ,image4--,! /r5g!n+ ( ! ,image by means ( ,hyposulphite ( ,gold #aga ,section ,,ii4--,! ,processes ( ,talbot1 etc4--,! ,calotype4--,! ,wax$ ,pap] ,process ( ,le ,grey4--,! ,album5 ,negative ,process4--,taup5ot's ,collodio-,album5 ,process #agf ,,"p ,,ii4 ,,practical ,,details ,,( ,,! ,,collodion ,,process4 ,,*apt] ,i4 ,,prep>ation ,,( ,,collodion4 ,mode ( prep>+ soluble ,pyroxyl9e by ! mix$ ,acids--by ! ,nitre process4--,purification ( ! ,e!r & ,alcohol4--,prep>ation ( ! iodiz+ comp\nds 9 a /ate ( purity #ahe ,,*apt] ,,ii4 ,,=mul ,,= ,,solutions ,,requir$ ,,= ,,collodion ,,photographs4 ,section ,i4--,=mul = direct ,positive ,solutions4--,! ,collodion4--,! ,nitrate ,ba?4--,develop+ fluids4--,fix+ liquids4--,:it5+ solution #bja ,section ,,ii4--,=mula = ,negative ,solutions4--,! ,collodion4--,! ,nitrate ,ba?4--,develop+ fluid4--,fix+ liquid #bjh ,,*apt] ,,iii4 ,,manipulations ,,( ,,! ,,collodion ,,process4 ,section ,i4--,manipulations ) moi/ ,collodion4--,clean+ ! ,plates4--,coat+ ) ,collodion4--,excit+4--,expos+4--,develo p+4 --,fix+ #bac ,section ,,ii4--,simple directions = ! use ( ,photographic ,l5ses4--,portrait ,l5ses4--,view ,l5ses4--,mode ( f9d+ ! *emical ,focus #bbg ,section ,,iii4--,on copy+ ,engrav+s1 ,et*+s1 ,diagrams1 etc4--,mode ( int5sify+ ! ,collodion #bca ,section ,,iv4--,rules = tak+ ,/]eoscopic ,photographs4--,mr4 ,latim] ,cl>k's arrangem5t = work+ ) a s+le ,cam]a #bcb ,section ,v4--,! ,photographic del9eation ( ,microscopic ,objects4--,arrangem5t ( ! app>atus4--,mode ( f9d+ ! *emical ,focus4--,use ( artificial light #bce ,,*apt] ,,iv4 ,,! ,,details ,,( ,,photographic ,,pr9t+4 ,section ,i4--,positive ,pr9t+ by ! ord9>y process4--,selection ( ! pap]4--,prep>ation ( ,album9iz$ pap]--( pla9 pap]--( ,ammonio-,nitrate ,pap]4--,prep>ation ( ! fix+ & ton+ ,ba?4--,manipulatory details ( ,photographic ,pr9t+4--,mode ( wa%+ & m\nt+ ! ,pro(s #bdj ,section ,,ii4--,positive ,pr9t+ by ,developm5t4--,a process on ,*loride & ,citrate ( ,silv]4--,on ,iodide ( ,silv]4--,on ,bromide ( ,silv] #bei ,section ,,iii4--,! ,sel d',or ,process = ton+ ,positives4--,prep>ation ( ! ton+ ,ba?4--,manipulatory details #bfg ,section ,,iv4--,on ,pr9t+ enl>g$ ,positives1 ,transp>5cies1 etc41 ^u ,collodion #bgb ,,*apt] ,v4 ,,classification ,,( ,,causes ,,( ,,failure ,,9 ,,! ,,collodion ,,process4 ,section ,i4--,imp]fections 9 ,negative & ,positive ,collodion ,photographs4--,fogg+4--,transp>5t & opaque spots4--,m>k+s ( all k9ds--"u- & ov]-exposure1 etc4 #bgf ,section ,,ii4--,imp]fections 9 ,pap] ,positives #bhe ,,*apt] ,,vi4 ,,l&scape ,,photography ,,by ,,! ,,collodion ,,pres]vative ,,& ,,collodio-,,album5 ,,processes4 ,! ,honey ,keep+ ,process4--,! ,oxymel ,process4--,photography on dry ,collodion4--,taup5ot's ,collodio-,album5 ,process #bhh ,,"p ,,iii4 ,,outl9es ,,( ,,g5]al ,,*emi/ry4 ,,*apt] ,i4 ,,! ,,*emical ,,elem5ts ,,& ,,_! ,,comb9ations4 ,! m important ,elem5t>y ,bodies1 ) _! ,symbols & ,atomic ,weights4--,! ,comp\nds =m$ by _! union4--,! class ( ,salts4--,illu/rations ( ! nature ( ,*emical ,aff9ity4--,*emical ,nom5clature4--,symbolic ,notation4--,! ,laws ( ,comb9ation4--,! ,atomic ,!ory4--,! ,*emi/ry ( ,organic ,bodies #cje ,,*apt] ,,ii4 ,vocabul>y ( ,photographic ,*emicals #cbg ,,app5dix4 ,quantitative te/+ ( ,nitrate ,ba?s4--,recov]y ( ,silv] f wa/e solutions4--,r$uction ( ,*loride ( ,silv]4--,mode ( tak+ ! ,specific ,gravity ( liquids4--,on ,filtration4--,! use ( ,te/-pap]s4--,! removal ( ,silv] /a9s f ! h&s1 etc4--,dr4 ,ure's tables ( ! /r5g? ( ,sulphuric & ,nitric ,acid ( diff]5t d5sities4--,table ( ,weights & ,measures #cga ,a ,,manual ,,( ,,photographic ,,*emi/ry4 ,illu/ration ,,introduction4 ,9 attempt+ to imp>t k on any subject1 x is n suffici5t t ! writ] %\ld himself be acqua9t$ ) t :i* he pr(esses to tea*4 ,ev5 suppos+ su* to be ! case1 yet mu* ( ! success ( 8 ef=t mu/ dep5d ^u ! mann] 9 :i* ! in=mation is convey$2 = z1 on ! "o h&1 a sy/em ( extreme brevity always fails ( its object1 s1 on ! o!r1 a m]e compilation ( facts imp]fectly expla9$ t5ds only to confuse ! read]4 ,a middle c\rse betwe5 ^! extremes is p]haps ! be/ to adopt2 t is1 to make selection ( c]ta9 fundam5tal po9ts1 & to expla9 !m ) "s m9ut5ess1 leav+ o!rs ( less importance to be dealt ) 9 a m summ>y mann]1 or to be altoge!r omitt$4 ,b indep5d5tly ( obs]vations ( ?is k9d1 :i* apply to educational in/ruction 9 g5]al1 x may be rem>k$1 t !re are sometimes difficulties ( a m =midable description to be ov]come4 ,= in/ance1 9 treat+ ( any sci5ce1 su* z t ( ,photography1 :i* may be said to be comp>atively new & unexplor$1 !re is great dang] ( errone\sly attribut+ effects to _! wrong causes6 ,p]haps none b he :o has himself work$ 9 ! laboratory c e/imate ?is po9t 9 its prop] light4 ,9 an exp]im5t :]e ! quantities ( mat]ial act$ ^u are inf9itesimally small1 & ! *emical *anges involv$ ( a mo/ ref9$ & subtle description1 x is soon discov]$ t ! slighte/ v>iation 9 ! usual conditions w suffice to alt] ! result4 ,nev]!less ,photography is truly a sci5ce1 gov]n$ by fix$ laws2 & h5ce1 z our k increases1 we may fairly hope t unc]ta9ty w cease1 & ! same precision at l5g? be atta9$ z t ) :i* *emical op]ations are usually p]=m$4 ,! int5tion ( ! au?or 9 writ+ ?is "w1 is to imp>t a ?or\gh k ( :at may be t]m$ ! ,fir/ ,pr9ciples ( ,photography1 t ! amateur may arm himself ) a !oretical acqua9tance ) ! subject be=e proce$+ to ! practice ( x4 ,to assi/ ?is object1 c>e w be tak5 to avoid ne$less complexity 9 ! =mul1 & all +r$i5ts w be omitt$ :i* are n prov$ to be ( s]vice4 ,! impurities ( *emicals w be po9t$ out z f> z possible1 & special directions giv5 = _! removal4 ,among/ ! v>iety ( ,photographic processes devis$1 ^? only w be select$ :i* are correct on !oretical gr\nds1 & are f\nd 9 practice to succe$4 ,z ! "w is address$ to "o suppos$ to be unacqua9t$ bo? ) ,*emi/ry & ,photography1 pa9s w be tak5 to avoid ! employm5t ( all te*nical t]ms ( :i* an explanation has n previ\sly be5 giv54 ,a ,,sket* ,,( ,,! ,,ma9 ,,divisions ,,to ,,be ,,adopt$1 ,,) ,,! ,,pr9cipal ,,subject-,,matt] ,,( ,,ea*4 ,! title giv5 to ! ,"w is ,a ,manual ( ,photographic ,*emi/ry1 & x is propos$ to include 9 x a famili> explanation ( ! nature ( ! v>i\s *emical ag5ts employ$ 9 ! ,art ( ,photography1 ) ! rationale ( ! mann] 9 :i* !y are ?\ght to act4 ,! division adopt$ is ?reefold3-- ,"p ,i4 ent]s m9utely into ! !ory ( ,photographic processes2 ,"p ,,ii4 treats ( ! practice ( ,photography ^u ,collodion2 ,"p ,,iii4 embraces a simple /atem5t ( ! ma9 laws ( ,*emi/ry1 ) ! pr9cipal prop]ties ( ! v>i\s sub/ances1 elem5t>y or comp\nd1 :i* are employ$ by ,photograph]s4 ,"p ,i41 or ! ,sci5ce ( ,photography1 includes a full description ( ! *emical action ( ,light ^u ! ,salts ( ,silv]1 ) its application to arti/ic purposes2 all m5tion ( manipulatory details1 & ( quantities ( +r$i5ts1 be+1 z a rule1 omitt$4 ,9 ?is division ( ! ,"w w be f\nd n9e ,*apt]s1 ! cont5ts ( :i* are z foll[s3-- ,*apt] ,i4 is a sket* ( ! hi/ory ( ,photography1 int5d$ to convey a g5]al notion ( ! orig9 & progress ( ! ,art1 )\t dwell+ on m9ute p>ticul>s4 ,*apt] ,,ii4 describes ! ,*emi/ry ( ! ,salts ( ,silv] employ$ by ,photograph]s2 _! prep>ation & prop]ties2 ! ph5om5a ( ! action ( ,light ^u !m1 ) exp]im5ts illu/rat+ x4 ,*apt] ,,iii4 leads u on to ! =mation ( an invisible image ^u a s5sitive surface1 ) ! developm5t or br++ out to view ( ! same by means ( *emical re-ag5ts4 ,?is po9t1 be+ ( elem5t>y importance1 is describ$ c>efully2--! r$uction ( metallic oxides1 ! prop]ties ( ! bodies employ$ to r$uce1 & ! hypo!ses :i* h be5 ent]ta9$ on ! nature ( ! ,light's action1 are all m9utely expla9$4 ,*apt] ,,iv4 treats ( ! fix+ ( ,photographic impressions1 9 ord] to r5d] !m inde/ructible by diffus$ light4 ,*apt] ,v4 conta9s a sket* ( ! ,optics ( ,photography--! decomposition ( :ite ,light into its elem5t>y rays1 ! ,photographic prop]ties ( ! diff]5t col\rs1 ! refraction ( ,light1 & con/ruction ( ,l5ses4 ,9 ! la/ ,section ( ! same ,*apt] w be f\nd a %ort sket* ( ! hi/ory & use ( ! ,/]eoscope4 ,*apt] ,,vi4 embraces a m m9ute description ( ! s5sitive ,photographic processes ^u ,collodion4 ,9 x is expla9$ ! *emi/ry ( ,pyroxyl9e1 ) its solution 9 ,alcoholiz$ ,e!r1 or ,collodion2 also ! ,photographic prop]ties ( ,iodide ( ,silv] ^u ,collodion1 ) ! causes :i* affect its s5sitiv5ess to ,light1 & ! action ( ! develop+ solutions 9 br++ out ! image4 ,*apt] ,,vii4 cont9ues ! same subject1 describ+ ! classification ( ,collodion ,photographs z ,positives & ,negatives1 ) ! di/9ctive peculi>ities ( ea*4 ,*apt] ,,viii4 conta9s ! !ory ( ! production ( ,positive ,photographs ^u pap]4 ,9 ?is ,*apt] w be f\nd an explanation ( ! some:at complex *emical *anges involv$ 9 pr9t+ ,positives1 ) ! precautions :i* are requir$ to ensure ! p]man5cy ( ! pro(s4 ,*apt] ,,ix4 is supplem5t>y to ! o!rs1 & a brief notice ( x w suffice4 ,x expla9s ! !ory ( ! ,photographic processes ( ,dagu]re & ,talbot2 especially notic+ ^? po9ts 9 :i* !y may be contra/$ ) ,photography ^u ,collodion1 b omitt+ all description ( manipulatory details1 :i* if includ$ w\ld ext5d ! ,"w beyond its propos$ limits4 ,! title ( ! second pr9cipal division ( ! ,"w1 viz4 ,! practice ( ,photography ^u ,collodion1 expla9s itself4 ,att5tion h[ev] may be invit$ to ! fif? ,*apt]1 9 :i* a classification is giv5 ( ! pr9cipal imp]fections 9 ,photographs1 ) %ort directions = _! removal2 & to ,*apt] ,,vi41 :i* describes ! pres]vation ( ! s5sitiv5ess ( ,collodion plates & ! mode ( op]at+ ^u films ( ,album5iz$ ,collodion4 ,9 ,"p ,,iii4 w be f\nd1 9 addition to a /atem5t ( ! laws ( *emical comb9ation1 etc41 a li/ ( ,photographic *emicals1 alphabetically arrang$1 includ+ _! prep>ation & prop]ties z f> z requir$ = _! employm5t 9 ! ,art4 ,! read] w at once ga!r f ?is sket* ( ! cont5ts ( ! volume be=e him1 t :il/ ! g5]al !ory ( e ,photographic process is describ$1 ) ! prep>ation & prop]ties ( ! *emicals employ$1 m9ute directions 9 ! m9or po9ts ( manipulation are re/rict$ to ,photography ^u ,collodion1 t bran* ( ! ,art be+ ! "o to :i* ! "t & att5tion ( ! au?or h be5 especially direct$4 ,collodion is all[$ by all to be ! be/ vehicle = ! s5sitive ,silv] ,salts :i* is at pres5t kn[n1 & successful results c be obta9$ ) a v small exp5diture ( "t & tr\ble1 if ! solutions employ$ 9 ! process are prep>$ 9 a /ate ( purity4 ,,*apt] ,i4 ,,hi/orical ,,sket* ,,( ,,photography4 ,! ,art ( ,photography1 :i* has n[ atta9$ su* p]fection1 & has become s popul> among/ all classes1 is "o ( comp>atively rec5t introduction4 ,! ^w ,photography means lit]ally writ+ by means ( ,light2 & x includes all processes by :i* any k9d ( picture c be obta9$ by ! *emical ag5cy ( ,light1 )\t ref]5ce to ! nature ( ! s5sitive surface ^u :i* x acts4 ,! philosoph]s ( antiquity1 al?\gh *emical *anges due to ! influ5ce ( ,light 7 cont9ually pass+ be=e _! eyes1 d n appe> to h direct$ _! att5tion to !m4 ,"s ( ! ,al*emi/s inde$ notic$ ! fact t a sub/ance :i* !y t]m$ ,horn ,silv]1 :i* 0 probably a ,*loride ( ,silv] :i* _h und]gone fusion1 became black5$ by exposure to ,light2 b _! ideas on su* subjects be+ ( ! mo/ errone\s nature1 no?+ result$ f ! discov]y4 ,! fir/ philosophical exam9ation ( ! decompos+ action ( ,light ^u comp\nds conta9+ ,silv] 0 made by ! illu/ri\s ,s*eele1 no long] ?an ?ree-qu>t]s ( a c5tury ago1 viz4 9 #aggg4 ,x 0 also rem>k$ by him t "s ( ! col\r$ rays ( ,light 7 peculi>ly active 9 promot+ ! *ange4 ,e>lie/ application ( ^! facts to purposes ( ,art4--,! fir/ attempts to r5d] ! black5+ ( ,silv] ,salts by ,light available = arti/ic purposes 7 made by ,w$gwood & ,davy ab\t ,a4,d4 #ahjb4 ,a %eet ( :ite pap] or ( :ite lea!r 0 saturat$ ) a solution ( ,nitrate ( ,silv]1 & ! %ad[ ( ! figure int5d$ to be copi$ project$ ^u x4 ,"u ^! circum/ances ! "p on :i* ! %ad[ fell rema9$ :ite1 :il/ ! surr\nd+ expos$ p>ts gradually d>k5$ "u ! influ5ce ( ! sun's rays4 ,un=tunately ^! & simil> exp]im5ts1 :i* appe>$ at ! outset to promise well1 7 *eck$ by ! exp]im5tali/s be+ unable to discov] any means ( fix+ ! pictures1 s z to r5d] !m inde/ructible by diffus$ ,light4 ,! un*ang$ ,silv] ,salt be+ p]mitt$ to rema9 9 ! :ite portions ( ! pap]1 naturally caus$ ! pro(s to black5 9 e "p1 unless c>efully pres]v$ 9 ! d>k4 ,introduction ( ! ,cam]a ,obscura1 & o!r ,improvem5ts 9 ,photography4--,! ,cam]a ,obscura1 or d>k5$ *amb]1 by means ( :i* a lum9\s image ( an object may be =m$1 0 inv5t$ by ,bapti/a ,porta1 ( ,padua2 b ! prep>ations employ$ by ,w$gwood 7 n suffici5tly s5sitive to be easily affect$ by ! subdu$ light ( t in/rum5t4 ,9 ! ye> #ahad1 h[ev]1 twelve ye>s subsequ5t to ! publication ( ,w$gwood's pap]1 ,m4 ,nipce1 ( ,*alons1 hav+ direct$ 8 att5tion to ! subject1 succe$$ 9 p]fect+ a process 9 :i* ! ,cam]a c\ld be employ$1 al?\gh ! s5sibility 0 /ill s l[ t an exposure ( "s h\rs 0 requir$ to produce ! effect4 ,9 ! process ( ,m4 ,nipce1 :i* 0 t]m$ ,heliography1 or sun-draw+1 ! use ( ! ,silv] ,salts 0 disc>d$1 & a res9\s sub/ance1 kn[n z ,bitum5 ( ,juda1 sub/itut$4 ,?is res9 0 sme>$ on ! surface ( a metal plate1 & expos$ to ! lum9\s image4 ,! light 9 act+ ^u x s *ang$ its prop]ties1 t x became insoluble 9 c]ta9 ess5tial oils4 ,h5ce1 on subsequ5t treatm5t ) ! oleag9\s solv5t1 ! %ad[s dissolv$ away1 & ! lights 7 repres5t$ by ! unalt]$ res9 rema9+ on ! plate4 ,! ,discov]ies ( ,m4 ,dagu]re4--,,mm4 ,nipce & ,dagu]re appe> at "o "t to h be5 associat$ z p>tn]s1 = ! purpose ( mutually prosecut+ _! rese>*es2 b x 0 n until aft] ! dea? ( ! =m]1 viz4 9 #ahci1 t ! process nam$ ! ,dagu]reotype 0 giv5 to ! _w4 ,dagu]re 0 dissatisfi$ ) ! sl[ness ( action ( ! ,bitum5 s5sitive surface1 & direct$ 8 att5tion ma9ly to ! use ( ! ,salts ( ,silv]1 :i* are ?us aga9 br\ght be=e our notice4 ,ev5 ! e>li] specim5s ( ! ,dagu]reotype1 al?\gh f> inf]ior to ^? subsequ5tly produc$1 possess$ a beauty :i* _h n be5 atta9$ by any ,photographs prior to t "t4 ,! s5sitive plates ( ,dagu]re 7 prep>$ by expos+ a silv]$ tablet to ! action ( ! vap\r ( ,iod9e1 s z to =m a lay] ( ,iodide ( ,silv] ^u ! surface4 ,by a %ort exposure 9 ! ,cam]a an effect 0 produc$1 n visible to ! eye1 b appe>+ :5 ! plate 0 subject$ to ! vap\r ( ,m]cury4 ,?is feature1 viz4 ! production ( a lat5t image ^u ,iodide ( ,silv]1 ) its subsequ5t developm5t by a *emical reag5t1 is "o ( ! fir/ importance4 ,its discov]y at once r$uc$ ! "t ( tak+ a picture f h\rs to m9utes1 & promot$ ! utility ( ! ,art4 ,dagu]re also succe$$ 9 fix+ 8 pro(s1 by removal ( ! unalt]$ ,iodide ( ,silv] f ! %ad[s4 ,! processes employ$ h[ev] 7 imp]fect1 & ! matt] 0 n set at re/ until ! publication ( a pap] by ,sir ,john ,h]s*el1 on ! prop]ty possess$ by ,hyposulphites ( dissolv+ ! ,salts ( ,silv] insoluble 9 wat]4 ,on a means ( ,multiply+ ,photographic ,impressions1 & o!r ,discov]ies ( ,mr4 ,fox ,talbot4--,! fir/ communication made to ! ,royal ,society by ,mr4 ,fox ,talbot1 9 ,janu>y1 #ahci1 includ$ only ! prep>ation ( a s5sitive pap] = copy+ objects by application4 ,x 0 direct$ t ! pap] %\ld be dipp$ fir/ 9 solution ( ,*loride ( ,sodium1 & !n 9 ,nitrate ( ,silv]4 ,9 ?is way a :ite sub/ance t]m$ ,*loride ( ,silv] is =m$1 m s5sitive to light ?an ! ,nitrate ( ,silv] orig9ally employ$ by ,w$gwood & ,davy4 ,! object is laid 9 contact ) ! prep>$ pap]1 &1 be+ expos$ to light1 a copy is obta9$1 :i* is ,negative1--id e/1 ) ! light & %ade rev]s$4 ,a second %eet ( pap] is !n prep>$1 & ! fir/1 or ,negative impression1 laid ^u x1 s z to all[ ! sun's light to pass ?r\gh ! transp>5t p>ts4 ,"u ^! circum/ances1 :5 ! ,negative is rais$1 a natural repres5tation ( ! object is f\nd bel[2 ! t9ts hav+ be5 aga9 rev]s$ by ! second op]ation4 ,?is production ( a ,negative ,photograph1 f :i* any numb] ( ,positive copies may be obta9$1 is a c>d9al po9t 9 ,mr4 ,talbot's inv5tion1 & "o ( great importance4 ,! pat5t issu$ = ! process nam$ ,talbotype or ,calotype dates f ,febru>y1 #ahda4 ,a %eet ( pap] is fir/ coat$ ) ,iodide ( ,silv] by soak+ x alt]nately 9 ,iodide ( ,potassium & ,nitrate ( ,silv]2 x is !n wa%$ ) solution ( ,gallic ,acid conta9+ ,nitrate ( ,silv] 7sometimes t]m$ ,gallo-,nitrate ( ,silv]71 by :i* ! s5sibility to light is greatly augm5t$4 ,an exposure 9 ! ,cam]a ( "s seconds or m9utes1 accord+ to ! brightness ( ! light1 impresses an invisible image1 :i* is br\ght out by treat+ ! plate ) a fre% portion ( ! mixture ( ,gallic ,acid & ,nitrate ( ,silv] employ$ 9 excit+4 ,on ! use ( ,glass ,plates to reta9 ,s5sitive ,films4--,! pr9cipal defects 9 ! ,calotype process are attributable to ! co>se & irregul> /ructure ( ! fibre ( pap]1 ev5 :5 manufactur$ ) ! greate/ c>e1 & expressly = ,photographic purposes4 ,9 consequ5ce ( ?is1 ! same am\nt ( exquisite def9ition & %>pness ( outl9e z t result+ f ! use ( metal plates1 _c be obta9$4 ,we are indebt$ to ,sir ,john ,h]s*el = ! fir/ employm5t ( glass plates to receive s5sitive ,photographic films4 ,! ,iodide ( ,silv] may be reta9$ ^u ! glass by means ( a lay] ( ,album5 or :ite ( egg1 z propos$ by ,m4 ,nipce de ,sa9t-,victor1 nephew to ! orig9al discov]] ( ! same "n4 ,a m important improvem5t /ill is ! employm5t ( ,collodion = a simil> purpose4 ,collodion is an e!real solution ( a sub/ance almo/ id5tical ) ,gun-,cotton4 ,on evaporation x leaves a transp>5t lay]1 resembl+ gold-beat]'s sk91 :i* adh]es to ! glass ) "s t5acity4 ,m4 ,le ,grey ( ,p>is orig9ally sugge/$ t ?is sub/ance might possibly be r5d]$ available 9 ,photography1 b our own c\ntryman1 ,mr4 ,ar*]1 0 ! fir/ to c>ry out ! idea practically4 ,9 a communication to ',! ,*emi/' 9 ! autumn ( #ahea1 ?is g5tleman gave a description ( ! ,collodion process mu* z x n[ /&s2 at ! same "t propos+ ! sub/itution ( ,pyro-gallic acid = ! ,gallic acid previ\sly employ$ 9 develop+ ! image4 ,at t p]iod no idea c\ld h be5 ent]ta9$ ( ! /imulus :i* ?is discov]y w\ld r5d] to ! progress ( ! ,art2 b exp]i5ce has n[ abundantly demon/rat$1 t1 z f> z all qualities mo/ desirable 9 a ,photographic process are conc]n$1 none at pres5t kn[n c excel1 or p]haps equal1 ! ,collodion process4 ,,*apt] ,,ii4 ,,! ,,salts ,,( ,,silv] ,,employ$ ,,9 ,,photography4 ,by ! t]m ,salt ( ,silv] we und]/& t ! comp\nd 9 "q conta9s ,silv]1 b n 9 its elem5t>y =m2 ! metal is 9 fact 9 a /ate ( *emical union ) o!r elem5ts :i* disguise its physical prop]ties1 s t ! ,salt possesses none ( ! ext]nal *>act]s ( ! ,silv] f :i* x 0 produc$4 ,silv] is n ! only metal :i* =ms ,salts2 !re are ,salts ( ,lead1 ,copp]1 ,iron1 etc4 ,sug> ( ,lead is a famili> in/ance ( a ,salt ( ,lead4 ,x is a :ite cry/all9e body1 easily soluble 9 wat]1 ! solution possess+ an int5sely sweet ta/e2 *emical te/s prove t x conta9s ,lead1 al?\gh no suspicion ( su* a fact c\ld be ent]ta9$ f a consid]ation ( its g5]al prop]ties4 ,common ,salt1 or ,*loride ( ,sodium1 :i* is ! type ( ! salts g5]ally1 is con/itut$ 9 a simil> mann]2 t is to say1 x conta9s a metallic sub/ance1 ! *>act]s ( :i* are mask$1 & lie hid 9 ! comp\nd4 ,! cont5ts ( ?is ,*apt] may be arrang$ 9 ?ree ,sections3 ! fir/ describ+ ! ,*emi/ry ( ! ,salts ( ,silv]2 ! second1 ! action ( ,light ^u !m2 ! ?ird1 ! prep>ation ( a s5sitive surface1 ) exp]im5ts illu/rat+ ! =mation ( ! ,photographic image4 ,,section ,i4 ,*emi/ry ( ! ,salts ( ,silv]4 ,! pr9cipal ,salts ( ,silv] employ$ 9 ! ,photographic processes are f\r 9 numb]1 viz4 ,nitrate ( ,silv]1 ,*loride ( ,silv]1 ,iodide ( ,silv]1 & ,bromide ( ,silv]4 ,9 addition to ^!1 x w be necess>y to describe ! ,oxides ( ,silv]4 ,,! ,,prep>ation ,,& ,,prop]ties ,,( ,,! ,,nitrate ,,( ,,silv]4 ,nitrate ( ,silv] is prep>$ by dissolv+ metallic ,silv] 9 ,nitric ,acid4 ,nitric ,acid is a p[]fully acid & corrosive sub/ance1 conta9+ two elem5t>y bodies unit$ 9 def9ite proportions4 ,^! are ,nitrog5 & ,oxyg52 ! latt] be+ pres5t 9 greate/ quantity4 ,nitric ,acid is a p[]ful solv5t = ! metallic bodies g5]ally4 ,to illu/rate its action 9 t p>ticul>1 z contra/$ ) o!r acids1 place pieces ( silv]-foil 9 two te/-tubes1 ! "o conta9+ dilute ,sulphuric1 ! o!r dilute ,nitric ,acid2 on ! application ( heat a viol5t action soon comm5ces 9 ! latt]1 b ! =m] is unaffect$4 ,9 ord] to und]/& ?is1 x mu/ be borne 9 m9d t :5 a metallic sub/ance dissolves 9 an acid1 ! nature ( ! solution is diff]5t f t ( an aque\s solution ( salt or sug>4 ,if salt wat] be boil$ d[n until ! :ole ( ! wat] has evaporat$1 ! salt is recov]$ ) prop]ties ! same z at fir/2 b if a simil> exp]im5t be made ) a solution ( ,silv] 9 ,nitric ,acid1 ! result is diff]5t3 9 t case metallic ,silv] is n obta9$ on evaporation1 b ,silv] comb9$ ) ,oxyg5 & ,nitric ,acid1 bo? ( :i* are /rongly reta9$1 be+ 9 fact 9 a /ate ( *emical comb9ation ) ! metal4 ,if we closely exam9e ! effects produc$ by treat+ ,silv] ) ,nitric ,acid1 we f9d !m to be ( ! foll[+ nature3--fir/1 a c]ta9 am\nt ( ,oxyg5 is imp>t$ to ! metal1 s z to =m an ,oxide1 :i* ,oxide dissolves 9 ano!r portion ( ! ,nitric ,acid1 produc+ ,nitrate ( ! ,oxide1 or1 z x is %ortly t]m$1 ,nitrate ( ,silv]4#a #a ,! prep>ation ( ,nitrate ( ,silv] f ! /&>d co9 ( ! realm is describ$ 9 ,"p ,,iii41 ,art4 ,silv]4 ,x is ! in/ability ( ,nitric ,acid !re=e--its pron5ess to "p ) ,oxyg5--:i* r5d]s x sup]ior to ! ,sulphuric & to mo/ acids 9 dissolv+ ,silv] & v>i\s o!r sub/ances1 bo? organic & inorganic4 ,prop]ties ( ,nitrate ( ,silv]4--,9 prep>+ ,nitrate ( ,silv]1 :5 ! metal has dissolv$1 ! solution is boil$ d[n & set aside to cry/allize4 ,! salt h[ev] z s obta9$ is /ill acid to te/-pap]1 & requires ei!r re-cry/allization1 or c>eful heat+ to ab\t #cjj ,fahr5heit4 ,x is ?is ret5tion ( small quantities ( ,nitric ,acid1 & sometimes probably ( ,nitr\s ,acid1 :i* r5d]s mu* ( ! comm]cial ,nitrate ( ,silv] useless = ,photography1 until r5d]$ neutral by fusion & a second cry/allization4 ,pure ,nitrate ( ,silv] occurs 9 ! =m ( :ite cry/all9e plates1 :i* are v heavy & dissolve readily 9 an equal weight ( cold wat]4 ,! solubility is mu* less5$ by ! pres5ce ( free ,nitric ,acid1 & 9 ! conc5trat$ ,nitric ,acid ! cry/als are almo/ insoluble4 ,boil+ ,alcohol takes up ab\t "o-f\r? "p ( its weight ( ! cry/alliz$ ,nitrate1 b deposits ne>ly ! :ole on cool+4 ,nitrate ( ,silv] has an int5sely bitt] & nause\s ta/e2 act+ z a cau/ic1 & corrod+ ! sk9 by a prolong$ application4 ,its aque\s solution does n r$d5 blue litmus-pap]4 ,heat$ 9 a crucible ! salt melts1 & :5 p\r$ into a m\ld & solidifi$1 =ms ! :ite lun> cau/ic ( comm]ce4 ,at a /ill high] temp]ature x is decompos$1 & bubbles ( ,oxyg5 ,gas are evolv$3 ! melt$ mass cool$ & dissolv$ 9 wat] leav+ beh9d a black p[d]1 & yield+ a solution1 :i* is fa9tly alkal9e to te/-pap]1 f ! pres5ce ( m9ute quantities ( ,nitrite or basic ,nitrite ( ,silv]4#b #b ,nitrite ( ,silv] diff]s f ! ,nitrate 9 conta9+ less ,oxyg51 & is =m$ f x by ! ab/raction ( two atoms ( t elem5t2 x is describ$ 9 ! vocabul>y1 ,"p ,,iii4 ,,! ,,*emi/ry ,,( ,,! ,,*lorides ,,( ,,silv]4 ,prep>ation ( ,proto*loride ( ,silv]4--,! ord9>y :ite ,*loride ( ,silv] may be prep>$ 9 two ways1--by ! direct action ( ,*lor9e ^u metallic ,silv]1 & by d\ble decomposition betwe5 two salts4 ,if a plate ( poli%$ silv] be expos$ to a curr5t ( ,*lor9e ,gas1#c x becomes aft] a %ort "t coat$ on ! surface ) a sup]ficial film ( :ite p[d]4 ,?is p[d] is ,*loride ( ,silv]1 conta9+ ! two elem5ts ,*lor9e & ,silv] unit$ 9 s+le equival5ts4 #c ,= ! prop]ties ( ! elem5t ,*lor9e1 see ! ?ird division ( ! ,"w4 ,prep>ation ( ,*loride ( ,silv] by d\ble decomposition4--,9 ord] to illu/rate ?is1 take a solution 9 wat] ( ,*loride ( ,sodium or common salt1 & mix x ) a solution conta9+ ,nitrate ( ,silv]2 imm$iately a d5se1 curdy1 :ite precipitate falls1 :i* is ! sub/ance 9 "q4 ,9 ?is reaction ! elem5ts *ange places2 ! ,*lor9e leaves ! ,sodium ) :i* x 0 previ\sly comb9$1 & crosses ov] to ! ,silv]2 ! ,oxyg5 & ,nitric ,acid are releas$ f ! ,silv]1 & unite ) ! ,sodium2 ?us ,*loride ( ,sodium plus ,nitrate ( ,silv] equals ,*loride ( ,silv] plus ,nitrate ( ,soda4 ,?is int]*ange ( elem5ts is t]m$ by *emi/s d\ble decomposition2 fur!r illu/rations ( x1 ) ! conditions necess>y to ! prop] e/abli%m5t ( ! process1 are giv5 9 ! fir/ ,*apt] ( ,"p ,,iii4 ,! ess5tial requirem5ts 9 two salts int5d$ = ! prep>ation ( ,*loride ( ,silv]1 are simply t ! fir/ %\ld conta9 ,*lor9e1 ! second ,silv]1 & t bo? %\ld be soluble 9 wat]2 h5ce ! ,*loride ( ,potassium or ,ammonium may be sub/itut$ = ! ,*loride ( ,sodium1 & ! ,sulphate or ,acetate = ! ,nitrate ( ,silv]4 ,9 prep>+ ,*loride ( ,silv] by d\ble decomposition1 ! :ite clotty masses :i* fir/ =m mu/ be wa%$ repeat$ly ) wat]1 9 ord] to free !m f soluble ,nitrate ( ,soda1 ! o!r product ( ! *ange4 ,:5 ?is is done1 ! salt is 9 a pure /ate1 & may be dri$1 etc41 9 ! usual way4 ,prop]ties ( ,*loride ( ,silv]4--,*loride ( ,silv] diff]s 9 appe>ance f ! ,nitrate ( ,silv]4 ,x is n usually cry/all9e1 b =ms a s(t :ite p[d] resembl+ common *alk or :it+4 ,x is ta/eless & insoluble 9 wat]2 unaffect$ by boil+ ) ! /ronge/ ,nitric ,acid1 b sp>+ly dissolv$ by conc5trat$ ,hydro*loric ,acid4 ,ammonia dissolves ,*loride ( ,silv] freely1 z d solutions ( ,hyposulphite ( ,soda & ,cyanide ( ,potassium4 ,conc5trat$ solutions ( alkal9e ,*lorides1 ,iodides1 & ,bromides are likewise solv5ts ( ,*loride ( ,silv]1 b to a limit$ ext5t1 z w be m fully %[n 9 ,*apt] ,,iv41 :5 treat+ ( ! modes ( fix+ ! ,photographic pro(s4 ,dry ,*loride ( ,silv] c>efully heat$ to r$ness fuses1 & concretes on cool+ into a t\gh & semi-transp>5t sub/ance1 :i* has be5 t]m$ horn silv] or luna cornea4 ,plac$ 9 contact ) metallic ,z9c or ,iron acidifi$ ) dilute ,sulphuric ,acid1 ,*loride ( ,silv] is r$uc$ to ! metallic /ate1 ! ,*lor9e pass+ to ! o!r metal "u ! decompos+ influ5ce ( ! galvanic curr5t :i* is e/abli%$4 ,prep>ation & ,prop]ties ( ! ,sub*loride ( ,silv]4--,if a plate ( poli%$ ,silv] be dipp$ 9 solution ( ,p]*loride ( ,iron1 or ( ,bi*loride ( ,m]cury1 a black /a9 is produc$1 ! ,iron or ,m]cury ,salt los+ a portion ( ,*lor9e1 :i* passes to ! ,silv] & conv]ts x sup]ficially into ,sub*loride ( ,silv]4 ,?is comp\nd diff]s f ! :ite ,*loride ( ,silv] 9 conta9+ less ,*lor9e2 ! composition ( ! latt] be+ repres5t$ by ! =mula ,ag,cl1 t ( ! =m] may p]haps be writt5 z ,ag#b;,cl7874 ,sub*loride ( ,silv] is int]e/+ to ! ,photograph] z correspond+ 9 prop]ties & composition ) ! ord9>y ,*loride ( ,silv] black5$ by light4 ,x is a pulv]ul5t sub/ance ( a blui%-black col\r n easily affect$ by ,nitric ,acid b decompos$ by fix+ ag5ts su* z ,ammonia1 ,hyposulphite ( ,soda1 or ,cyanide ( ,potassium1 into ,*loride ( ,silv] :i* dissolves1 & insoluble metallic ,silv]4 ,,! ,,*emi/ry ,,( ,,iodide ,,( ,,silv]4 ,! prop]ties ( ,iod9e are describ$ 9 ! ?ird division ( ! ,"w3 !y are analog\s to ^? ( ,*lor9e & ,brom9e1 ! ,silv] ,salts =m$ by ^! elem5ts be>+ also a /rong resemblance to ea* o!r4 ,prep>ation & ,prop]ties ( ,iodide ( ,silv]4--,iodide ( ,silv] may be =m$ 9 an analog\s mann] to ! ,*loride1 viz4 by ! direct action ( ! vap\r ( ,iod9e ^u metallic ,silv]1 or by d\ble decomposition1 betwe5 solutions ( ,iodide ( ,potassium & ,nitrate ( ,silv]4 ,:5 prep>$ by ! latt] mode x =ms an impalpable p[d]1 ! col\r ( :i* v>ies slightly ) ! mann] ( precipitation4 ,if ! ,iodide ( ,potassium be 9 excess1 ! ,iodide ( ,silv] falls to ! bottom ( ! vessel ne>ly :ite2 b ) an excess ( ,nitrate ( ,silv] x is ( a /raw-yell[ t9t4 ,?is po9t may be notic$1 because ! yell[ salt is ! "o adapt$ = ,photographic use1 ! o!r be+ ins5sible to ! influ5ce ( light4 ,iodide ( ,silv] is ta/eless & inodor\s2 insoluble 9 wat] & 9 dilute ,nitric ,acid4 ,x is sc>cely dissolv$ by ,ammonia1 :i* s]ves to di/+ui% x f ! ,*loride ( ,silv]1 freely soluble 9 t liquid4 ,hyposulphite ( ,soda & ,cyanide ( ,potassium bo? dissolve ,iodide ( ,silv]2 x is also soluble 9 solutions ( ! alkal9e ,bromides & ,iodides1 z w be fur!r expla9$ 9 ,*apt] ,,iv4 ,iodide ( ,silv] is r$uc$ by ,metallic ,z9c 9 ! same mann] z ! ,*loride ( ,silv]1 =m+ soluble ,iodide ( ,z9c & leav+ a black p[d]4 ,,! ,,prep>ation ,,& ,,prop]ties ,,( ,,bromide ,,( ,,silv]4 ,?is sub/ance s closely resembles ! correspond+ salts conta9+ ,*lor9e & ,iod9e1 t a %ort notice ( x w suffice4 ,bromide ( ,silv] is prep>$ by expos+ a silv]$ plate to ! vap\r ( ,brom9e1 or by add+ solution ( ,bromide ( ,potassium to ,nitrate ( ,silv]4 ,x is an insoluble sub/ance1 slightly yell[ 9 col\r1 & di/+ui%$ f ,iodide ( ,silv] by dissolv+ 9 /rong ,ammonia & 9 ,*loride ( ,ammonium4 ,x is freely soluble 9 ,hyposulphite ( ,soda & 9 ,cyanide ( ,potassium4 ,! prop]ties ( ! elem5t ,brom9e are describ$ 9 ,"p ,,iii4 ,,*emi/ry ,,( ,,! ,,oxides ,,( ,,silv]4 ,! ,protoxide ( ,silv] 7,ag ,o74--,if a little ,pota% or ,ammonia be add$ to solution ( ,nitrate ( ,silv]1 an olive-br[n sub/ance is =m$1 :i*1 on /&+1 collects at ! bottom ( ! vessel4 ,?is is ,oxide ( ,silv]1 displac$ f its previ\s /ate ( comb9ation ) ,nitric ,acid by ! /rong] oxide4 ,pota%4 ,oxide ( ,silv] is soluble to a v m9ute ext5t 9 pure wat]1 ! solution possess+ an alkal9e reaction to ,litmus2 x is easily dissolv$ by ,nitric or ,acetic ,acid1 =m+ a neutral ,nitrate or ,acetate2 also soluble 9 ,ammonia 7,ammonio-,nitrate ( ,silv]71 & 9 ,nitrate ( ,ammonia1 ,hyposulphite ( ,soda1 & ,cyanide ( ,potassium4 ,long exposure to light conv]ts x into a black sub/ance1 :i* is probably a ,suboxide4 ,! ,suboxide ( ,silv] 7,ag#b,o87--,?is sub/ance 0 obta9$ by ,f>aday on expos+ a solution ( ! ,ammonio-,nitrate ( ,silv] to ! action ( ! air4 ,x be>s a relation to ! ord9>y br[n ,protoxide ( ,silv] simil> to t :i* ! ,sub*loride be>s to ,proto*loride ( ,silv]4 ,suboxide ( ,silv] is a black or grey p[d]1 :i* assumes ! metallic lu/re on rubb+1 & :5 treat$ ) dilute ,acids is resolv$ into ,protoxide ( ,silv] :i* dissolves1 & metallic ,silv]4 ,,section ,,ii4 ,on ! ,photographic ,prop]ties ( ! ,salts ( ,silv]4 ,9 addition to ! ,salts ( ,silv] describ$ 9 ! fir/ ,section ( ?is ,*apt] !re are _m o!rs well kn[n to *emi/s1 z ! ,acetate ( ,silv]1 ! ,sulphate1 ! ,citrate ( ,silv]1 etc4 ,"s occur 9 cry/als :i* are soluble 9 wat]1 :il/ o!rs are pulv]ul5t & insoluble4 ,! ,salts ( ,silv] =m$ by col\rless ,acids are :ite :5 fir/ prep>$1 & rema9 s if kept 9 a d>k place2 b !y possess ! rem>kable peculi>ity ( be+ d>k5$ 9 col\r by exposure to ,light4 ,action ( ,light ^u ! ,nitrate ( ,silv]4--,! ,nitrate ( ,silv] is "o ( ! mo/ p]man5t ( ! ,silv] salts4 ,x may be pres]v$ un*ang$ 9 ! cry/all9e =m1 or 9 solution 9 di/ill$ wat]1 = an indef9ite l5g? ( "t1 ev5 :5 con/antly expos$ to ! diffus$ light ( day4 ,?is is p>tly expla9$ by ! nature ( ! acid ) :i* ,oxide ( ,silv] is associat$ 9 ! ,salt2 ,nitric ,acid1 possess+ /rong oxidiz+ prop]ties1 be+ oppos$ to ! d>k5+ influ5ce ( ,light ^u ! ,silv] comp\nds4 ,nitrate ( ,silv] may1 h[ev]1 be r5d]$ susceptible to ! influ5ce ( ,light1 by add+ to its solution organic matt]1 vegetable or animal4 ,! ph5om5a produc$ 9 ?is case are well illu/rat$ by dipp+ a pl$get ( cotton-wool1 or a %eet ( :ite pap]1 9 solution ( ,nitrate ( ,silv]1 & expos+ x to ! direct rays ( ! sun2 x sl[ly d>k5s1 until x becomes ne>ly black4 ,! /a9s ^u ! sk9 produc$ by h&l+ ,nitrate ( ,silv] are caus$ 9 ! same way1 & are se5 mo/ evid5tly :5 ! "p has be5 expos$ to light4 ,! v>ieties ( organic matt] :i* especially facilitate ! black5+ ( ,nitrate ( ,silv] are su* z t5d to absorb ,oxyg52 h5ce pure vegetable fibre1 free f ,*lorides1 su*1 = in/ance1 z ! ,sw$i% filt]+-pap]1 is n r5d]$ v s5sitive by be+ simply bru%$ ) solution ( ! ,nitrate1 b a little grape sug> add$ soon det]m9es ! decomposition4 ,decomposition ( ,*loride1 ,bromide1 & ,iodide ( ,silv] by ,light4--,pure moi/ ,*loride ( ,silv]#d *anges sl[ly f :ite to violet on exposure to light4 ,bromide ( ,silv] becomes ( a grey col\r1 b is less affect$ ?an ! ,*loride4 ,iodide ( ,silv] 7if free f excess ( ,nitrate ( ,silv]7 does n alt] 9 appe>ance by exposure ev5 to ! sun's rays1 b reta9s its yell[ t9t un*ang$4 ,( ^! ?ree comp\nds !re=e ,*loride ( ,silv] is ! mo/ readily act$ on by light1 & pap]s prep>$ ) ?is salt w become f> d>k] on exposure ?an o!rs coat$ ) ,bromide or ,iodide ( ,silv]4 #d ,! ,*loride "h spok5 ( is ! comp\nd prep>$ by add+ a soluble ,*loride to a solution ( ,nitrate ( ,silv]3 ! product ( ! direct action ( ,*lor9e ^u metallic ,silv] is sometimes ins5sitive to light4 ,!re are c]ta9 conditions :i* accel]ate ! action ( light ^u ! ,*loride ( ,silv]4 ,^! are1 fir/1 an excess ( ,nitrate ( ,silv]1 & second1 ! pres5ce ( organic matt]4 ,pure ,*loride ( ,silv] w\ld be useless z a ,photographic ag5t1 b a ,*loride ) excess ( ,nitrate is v s5sitive4 ,ev5 ,iodide ( ,silv]1 ord9>ily unaffect$1 is black5$ by light :5 moi/5$ ) a solution ( ! ,nitrate ( ,silv]4#e #e ,! read] w und]/& t ! ,acetate1 ,sulphate1 or any o!r soluble ,salt ( ,silv]1 might be sub/itut$ = ! ,nitrate 9 ?is exp]im5t4 ,organic matt] comb9$ ) ,*loride & ,nitrate ( ,silv] gives a /ill high] degree ( s5sibility1 & 9 ?is way ! ,photographic pap]s are prep>$4 ,! black5+ ( ,*loride ( ,silv] by ,light expla9$4--,?is may be /udi$ by susp5d+ pure ,*loride ( ,silv] 9 di/ill$ wat]1 & expos+ x to ! sun's rays = sev]al days4 ,:5 ! process ( d>k5+ has proce$$ to "s ext5t1 ! sup]natant liquid is f\nd to conta9 free ,*lor9e1 or1 9 place ( x4 ,hydro*loric ,acid 7,h ,cl71 ! result ( a subsequ5t action ( ! ,*lor9e ^u ! wat]4 ,! lum9\s rays appe> to loos5 ! aff9ity ( ! elem5ts ,*lor9e & ,silv] = ea* o!r2 h5ce a portion ( ,*lor9e is sep>at$1 & ! :ite ,proto*loride is conv]t$ into ! violet ,sub*loride ( ,silv]4 ,if an atom ( ,nitrate ( ,silv] be pres5t1 ! lib]at$ ,*lor9e unites ) x1 displac+ ,nitric ,acid1 & =m+ aga9 ,*loride ( ,silv]1 :i* is decompos$ 9 its turn4 ,! excess ( ,nitrate ( ,silv] ?us ex]ts an accel]at+ influ5ce ^u ! d>k5+ ( ,*loride ( ,silv]1 by r5d]+ ! *a9 ( *emical aff9ities m complete1 & prev5t+ an accumulation ( ,*lor9e 9 ! liquid1 :i* w\ld be a *eck to ! cont9uance ( ! action4 ,action ( ,light ^u organic ,salts ( ,silv]4--,on add+ dilut$ ,album51 or :ite ( egg1 to solution ( ,nitrate ( ,silv]1 a floccul5t deposit =ms :i* is a comp\nd ( ! animal matt] ) ,protoxide ( ,silv]1 & is kn[n z ,album9ate ( ,silv]4 ,?is sub/ance is at fir/ q :ite1 b on exposure to light x turns to a brick-r$ col\r4 ,! *ange :i* takes place is "o ( deoxidation1 ! ,protoxide ( ,silv] los+ a portion ( its ,oxyg51 & a ,suboxide ( ,silv]1 ! product ( ! r$uction1 rema9+ 9 union ) ! oxidiz$ ,album54 ,! r$ comp\nd may !re=e be loosely designat$ z an ,album9ate ( ,suboxide ( ,silv]4 ,gelat9e does n precipitate ,nitrate ( ,silv] 9 ! same mann] z ,album53 b if a %eet ( transp>5t ,gelat9e be all[$ to imbibe a solution ( ! ,nitrate1 x becomes ( a cle> ruby-r$ t9t on exposure to light1 & a true *emical comp\nd ( ,gelat9e1 or a product ( its oxidation1 ) a l[ ,oxide ( ,silv]1 is produc$4 ,case9e1 ! animal pr9ciple ( milk1 is coagulat$ by ,nitrate ( ,silv]1 & ! r$ sub/ance =m$ on expos+ ! curds to light may be view$ z analog\s 9 composition to ! correspond+ comp\nds ) ,album5 & ,gelat9e4 ,_m o!r organic salts ( ,silv] are d>k5$ by light4 ,! :ite ,citrate ( ,protoxide ( ,silv] *anges to a r$ sub/ance1 react+ ) *emical te/s 9 ! same mann] z ,whl]'s ,citrate ( ,suboxide ( ,silv]1 :i* he obta9$ by r$uc+ ! ord9>y ,citrate 9 ,hydrog5 ,gas4 ,glycyrrhiz91 ! ,sug> ( ,liquorice1 also =ms a :ite comp\nd ) ,oxide ( ,silv] :i* becomes br[n or r$ 9 ! sun's rays4#f #f ,= fur!r p>ticul>s on ! action ( light ^u ! ,salts ( ,silv] associat$ ) organic matt]1 see ! ,au?or's pap] on ! composition ( ! photographic image1 9 ! eigh? ,*apt]4 ,,simple ,,exp]im5ts ,,illu/rat+ ,,! ,,action ,,( ,,light ,,^u ,a ,,s5sitive ,,lay] ,,( ,,*loride ,,( ,,silv] ,,on ,,pap]4 ,9 ! p]=mance ( ! mo/ simple exp]im5ts on ! decomposition ( ,silv] ,salts by ,light1 ! /ud5t may employ ord9>y te/-tubes1 9 :i* small quantities ( ! two liquids requir$ = ! d\ble decomposition may be mix$ toge!r4 ,:5 h[ev] conc5trat$ solutions are us$ 9 ?is way1 ! insoluble ,silv] ,salt falls 9 d5se & clott$ masses1 :i*1 expos$ to ! sun's rays1 quickly black5 on ! ext]ior1 b ! inside is protect$1 & rema9s :ite4 ,x is ( importance !re=e 9 ,photography t ! s5sitive mat]ial %\ld exi/ 9 ! =m ( a surface1 9 ord] t ! v>i\s p>ticles ( :i* x is compos$ may ea* "o individually be br\ght into relation ) ! di/urb+ =ce4 ,full directions = ! prep>ation ( s5sitive ,photographic pap] are giv5 9 ! second division ( ?is "w4 ,! foll[+ is ! !ory ( ! process3--,a %eet ( pap] is treat$ ) solution ( ,*loride ( ,sodium or ,ammonium1 & subsequ5tly ) ,nitrate ( ,silv]2 h5ce results a =mation ( ,*loride ( ,silv] 9 a f9e /ate ( division1 ) an excess ( ,nitrate ( ,silv]1 ! ,silv] ba? hav+ be5 purposely made /rong] 9 proportion ?an ! salt+ solution4 ,illu/rative ,exp]im5t ,no4 ,i4--,place a squ>e ( s5sitive pap] 7prep>$ accord+ to ! directions giv5 9 ! ,second ,"p ( ! "w7 9 ! direct rays ( ! sun1 & obs]ve ! gradual process ( d>k5+ :i* takes place2 ! surface passes ?r\gh a v>iety ( *anges 9 col\r until x becomes ( a deep *ocolate-br[n4 ,if ! ,light is tol]ably int5se1 ! br[n %ades are probably rea*$ 9 f ?ree to five m9utes2 b ! s5sibility ( ! pap]1 & also ! nature ( ! t9ts1 w v>y mu* ) ! "* ( ! organic matt] pres5t4 ,exp]im5t ,no4 ,,ii4--,lay a device cut f black pap] ^u a %eet ( s5sitive pap]1 & compress ! two toge!r by means ( a %eet ( glass4 ,aft] a prop] l5g? ( exposure ! figure w be exactly copi$1 ! t9t h[ev] be+ rev]s$3 ! black pap] protect+ ! s5sitive ,*loride b5ea?1 produces a :ite figure ^u a d>k gr\nd4 ,exp]im5t ,no4 ,,iii4--,repeat ! la/ exp]im5t1 sub/itut+ a piece ( lace or gauze-wire = ! pap] device4 ,?is is int5d$ to %[ ! m9ut5ess ) :i* objects c be copi$1 s9ce ! smalle/ filam5t w be di/9ctly repres5t$4 ,exp]im5t ,no4 ,,iv4--,take an engrav+ 9 :i* ! contra/ ( light & %ade is tol]ably well m>k$1 & hav+ laid x closely 9 contact ) ! s5sitive pap]1 expose z be=e4 ,?is exp]im5t %[s t ! surface d>k5s 9 degrees proportionate to ! int5sity ( ! light1 s t ! half %ad[s ( ! engrav+ are accurately ma9ta9$1 & a pleas+ gradation ( tone produc$4 ,9 ! d>k5+ ( ,photographic pap]s1 ! action ( ! light is q sup]ficial1 & al?\gh ! black col\r may be int5se1 yet ! am\nt ( r$uc$ ,silv] :i* =ms x is s small t x _c conv5i5tly be e/imat$ by *emical reag5ts4 ,?is is well %[n by ! results ( an analysis p]=m$ by ! ,au?or1 9 :i* ! total weight ( ,silv] obta9$ f a black5$ %eet measur+ ne>ly #bd by #ah in*es am\nt$ to less ?an half a gra94 ,x becomes !re=e ( great importance 9 prep>+ s5sitive pap] to att5d to ! condition ( ! surface lay] ( p>ticles1 ! action r>ely ext5d+ to ^? b5ea?4 ,! use ( ,album51 ,gelat9e1 etc41 :i* w be expla9$ 9 ! eigh? ,*apt]1 has ref]5ce to ?is among/ o!r advantages1 & secures a bett] & m %>ply def9$ pr9t4 ,,*apt] ,,iii4 ,,on ,,! ,,developm5t ,,( ,,an ,,invisible ,,image ,,by ,,means ,,( ,a ,,r$uc+ ,,ag5t4 ,x has be5 %[n 9 ! previ\s ,*apt] t ! majority ( ! ,salts ( ,silv]1 bo? organic & inorganic1 are d>k5$ 9 col\r on exposure to light1 &1 by ! loss ( ,oxyg51 ,*lor9e1 etc41 become r$uc$ to ! condition ( ,subsalts4 ,_m ( ! same comp\nds are also susceptible ( a *ange "u ! influ5ce ( light1 :i* is ev5 m rem>kable4 ,?is *ange takes place aft] a comp>atively %ort exposure1 & z x does n affect ! appe>ance ( ! s5sitive lay]1 = "s "t x escap$ notice3 b x 0 aft]w>ds discov]$ t an impression1 be=e invisible1 might be br\ght out by treat+ ! plate ) c]ta9 *emical ag5ts :i* are )\t effect on ! orig9al un*ang$ salt1 b quickly black5 x aft] exposure4 ,x is a rem>kable fact t ! ,silv] comp\nds mo/ readily affect$ by light alone1 are n ! mo/ s5sitive to ! reception ( ! invisible image4 ,?us1 ( ,photographic pap]s prep>$ ) ,*loride1 ,bromide1 or ,iodide ( ,silv]1 ! =m] assume ! deepe/ %ade ( col\r "u ! influ5ce ( ! sun's rays1 b if all be expos$ mom5t>ily1 & !n remov$1 ! greate/ am\nt ( effect w be develop$ ^u ! ,iodide pap]4 ,iodide ( ,silv] !re=e is ! salt commonly us$ :5 s5sibility is an object1 b x %\ld be not$ t images ne>ly or q lat5t c be impress$ ^u _m o!r ( ! comp\nds ( ,silv]1 includ+ ^? belong+ to ! animal & vegetable k+doms4 ,exp]im5ts illu/rat+ ! ,=mation ( an ,invisible ,image4--,take a %eet ( s5sitive pap]1 prep>$ ) ,iodide ( ,silv] by ! me?od giv5 9 ! f\r? ,*apt] ( ,"p ,,ii41 & hav+ divid$ x into two p>ts1 expose "o ( !m to ! lum9\s rays = a few seconds4 ,no visible decomposition takes place1 b on remov+ ! pieces to a room dimly illum9at$1 & bru%+ ) a solution ( ,gallic ,acid1 a manife/ diff]5ce w be obs]v$2 ! "o be+ unaffect$1 :il/ ! o!r d>k5s gradually until x becomes black4 ,exp]im5t ,,ii4--,a prep>$ %eet is %ield$ 9 c]ta9 p>ts by an opaque sub/ance1 & !n aft] ! requisite exposure1 :i* is easily asc]ta9$ by a few trials1 treat$ ) ! ,gallic ,acid z be=e2 9 ?is case ! protect$ "p rema9s :ite1 :il/ ! o!r d>k5s to a great] or less ext5t4 ,9 ! same way1 copies ( leaves1 engrav+s1 etc4 may be made1 v correct 9 ! %ad+ & mu* resembl+ ^? produc$ by ! prolong$ action ( light alone ^u ! ,*loride ( ,silv]4 ,! object ( employ+ a sub/ance l ,gallic ,acid to develope or br+ out to view an invisible image1 9 pref]5ce to =m+ ! picture by ! direct action ( light1 unassi/$ by a develop]1 is ! economy ( "t !reby effect$4 ,?is is well %[n 9 ! results ( "s exp]im5ts conduct$ by ,m4 ,claudet 9 ! ,dagu]reotype process3 he f\nd t ) a s5sitive lay] ( ,bromo-,iodide ( ,silv]1 an int5sity ( light ?ree ?\s& times great] 0 requir$ if ! use ( a develop] 0 omitt$1 & ! exposure cont9u$ until ! picture became visible ^u ! plate4 ,to increase ! s5sitiv5ess ( ,photographic prep>ations is a po9t ( great consequ5ce2 & inde$1 :5 ! ,cam]a is us$1 f ! l[ int5sity ( ! lum9\s image =m$ 9 t in/rum5t1 no o!r plan ?an ! "o above describ$ w\ld be practicable4 ,h5ce ! advancem5t1 & inde$ ! v orig91 ( ! ,photographic ,art1 may be dat$ f ! fir/ discov]y ( a process = br++ out to view an invisible image by means ( a r$uc+ ag5t4 ,! pres5t ,*apt] is divid$ into ?ree ,sections3--fir/1 ! *emical prop]ties ( ! sub/ances usually employ$ z develop]s2--second1 _! mode ( action 9 r$uc+ ! ,salts ( ,silv]2--?ird1 hypo!ses on ! action ( light 9 impress+ a lat5t image4 ,,section ,i4 ,*emi/ry ( ! v>i\s ,sub/ances employ$ z ,develop]s4 ,developm5t is ess5tially a process ( r$uction1 or1 9 o!r words1 ( deoxidation4 ,if we take a c]ta9 metal1 we c1 by means ( ,nitric ,acid1 imp>t ,oxyg5 to x1 s t x becomes fir/ an ,oxide1 & aft]w>ds1 by solution ( ! ,oxide 9 ! excess ( acid1 a salt4 ,:5 ?is salt is =m$1 by a s]ies ( *emical op]ations ! rev]se ( ! =m] x may be depriv$ ( all its ,oxyg51 & ! metallic elem5t aga9 isolat$4 ,! degree ( facility ) :i* oxidation z well z r$uction is p]=m$1 dep5ds ^u ! aff9ity = ,oxyg5 :i* ! p>ticul> metal "u treatm5t possesses4 ,9 ?is respect !re is consid]able diff]5ce1 z may be %[n by a ref]5ce to ! two well-kn[n metals1 ,iron & ,gold4 ,h[ spe$ily does ! fir/ become t>ni%$ & cov]$ ) ru/1 :il/ ! o!r rema9s bright ev5 9 ! fire6 ,x is inde$ possible1 by a c>eful process1 to =m ,oxide ( ,gold2 b x reta9s its ,oxyg5 s loosely t ! m]e application ( heat is suffici5t to drive x (f1 & leave ! metal 9 a pure /ate4 ,silv]1 ,gold1 & ,plat9um all belong to ! class ( noble metals1 hav+ ! lea/ aff9ity = ,oxyg53 h5ce _! ,oxides are un/able1 & any body t5d+ /rongly to absorb ,oxyg5 w r$uce !m to ! metallic /ate4 ,obs]ve1 !re=e1 t ! sub/ances employ$ by ! ,photograph] to assi/ ! action ( ! light1 & to develope ! picture1 act by remov+ ,oxyg54 ,! s5sitive ,salt ( ,silv] is ?us r$uc$1 m or less completely1 9 ! p>ts t\*$ by light1 & an opaque deposit results :i* =ms ! image4#g #g ,^! rem>ks d n apply to ! vap\r ( ,m]cury employ$ z a develop+ ag5t 9 ! ,dagu]reotype4 ,! *emi/ry ( t process w be expla9$ 9 a sep>ate ,*apt]4 ,! mo/ important ( ! develop]s are z foll[s3-- ,gallic ,acid1 ,pyrogallic ,acid1 & ! ,protosalts ( ,iron4 ,,*emi/ry ,,( ,,gallic ,,& ,,pyrogallic ,,acids4 a4 ,( ,gallic ,acid4--,gallic ,acid is obta9$ f ,gall ,nuts1 :i* are peculi> excresc5ces =m$ ^u ! bran*es & %oots ( ! ,qu]cus infectoria by ! puncture ( a species ( insect4 ,! be/ k9d is import$ f ,turkey1 & sold 9 comm]ce z ,aleppo ,galls4 ,gall ,nuts d n conta9 ,gallic ,acid ready =m$1 b an analog\s *emical pr9ciple t]m$ ,tannic ,acid1 well kn[n = its a/r+5t prop]ties & employm5t 9 ! process ( tann+ raw hides4 ,gallic ,acid is produc$ by ! decomposition & oxidation ( ,tannic ,acid :5 p[d]$ galls are expos$ = a long "t 9 a moi/ /ate to ! action ( ! air4 ,by boil+ ! mass ) wat] & filt]+ :il/ hot1 ! acid is extract$1 & cry/allizes on cool+1 on acc\nt ( its sp>+ solubility 9 cold wat]4 ,gallic ,acid occurs 9 ! =m ( long silky ne$les1 soluble 9 #ajj p>ts ( cold & #c ( boil+ wat]2 !y are also readily soluble 9 ,alcohol1 b sp>+ly 9 ,e!r4 ,! aque\s solution becomes m\ldy on keep+1 to obviate :i*1 ! addition ( ,acetic ,acid or a drop or two ( ,oil ( ,cloves is recomm5d$4 ,gallic ,acid is a feeble acid1 sc>cely r$d5+ litmus2 x =ms salts ) ! alkal9e & e>?y bases1 su* z ,pota%1 ,lime1 etc41 b n ) ! oxides ( ! noble metals4 ,:5 add$ to ,oxide ( ,silv] ! metallic elem5t is sep>at$ & ! ,oxyg5 absorb$4 b4 ,pyrogallic ,acid4--,! t]m pyro prefix$ to ,gallic ,acid implies t ! new sub/ance is obta9$ by ! action ( heat ^u t body4 ,at a temp]ature ( ab\t #daj ,fahr41 ,gallic ,acid is decompos$1 & a :ite sublimate =ms1 :i* cond5ses 9 lamell> cry/als2 ?is is ,pyrogallic ,acid4 ,pyrogallic ,acid is v soluble 9 cold wat]1 & 9 ,alcohol & ,e!r2 ! solution decomposes & becomes br[n by exposure to ! air4 ,x gives an indigo blue col\r ) ,protosulphate ( ,iron1 :i* *anges to d>k gre5 if any ,p]sulphate be pres5t4 ,al?\gh t]m$ an acid1 ?is sub/ance is /rictly neutral2 x does n r$d5 litmus-pap]1 & =ms no salts4 ,! addition ( ,pota% or ,soda decomposes ,pyrogallic ,acid1 at ! same "t increas+ ! attraction = ,oxyg52 h5ce ?is mixture may conv5i5tly be employ$ = absorb+ ! ,oxyg5 conta9$ 9 atmosph]ic air4 ,! comp\nds ( ,silv] & ,gold are r$uc$ by ,pyrogallic ,acid ev5 m rapidly ?an by ,gallic ,acid1 ! r$uc+ ag5t absorb+ ! ,oxyg51 & becom+ conv]t$ into ,c>bonic ,acid & a br[n matt] insoluble 9 wat]4 ,comm]cial ,pyrogallic ,acid is (t5 contam9at$ ) empyreumatic oil1 & also ) a black insoluble sub/ance kn[n z ,metagallic ,acid1 :i* is =m$ :5 ! heat is rais$ above ! prop] temp]ature 9 ! process ( manufacture4 ,,*emi/ry ,,( ,,! ,,protosalts ,,( ,,iron4 ,! comb9ations ( ,iron ) ,oxyg5 are some:at num]\s4 ,!re are two di/9ct ,oxides :i* =m ,salts1 viz4 ! ,protoxide ( ,iron1 conta9+ an atom ( ,oxyg5 to "o ( metal2 & ! ,p]oxide1 ) an atom & a half ( ,oxyg5 to "o ( metal4 ,z half atoms h[ev] are n all[$ 9 *emical language1 x is usual to say t ! ,p]oxide ( ,iron conta9s ?ree equival5ts ( ,oxyg5 to two ( metallic ,iron4 ,express$ 9 symbols1 ! composition is z foll[s3-- ,protoxide ( ,iron1 ,fe ,o4 ,p]oxide ( ,iron1 ,fe#b,o#c4 ,! ,proto- & ,p]salts ( ,iron d n resemble ea* o!r 9 _! physical & *emical prop]ties4 ,! =m] are usually ( an apple-gre5 col\r1 & ! aque\s solutions almo/ col\rless1 if n highly conc5trat$4 ,! latt]1 on ! o!r h&1 are d>k1 & give a yell[ or ev5 blood-r$ solution4 ,! ,protosalts ( ,iron are alone useful 9 ,photography2 b ! foll[+ exp]im5t w s]ve to illu/rate ! prop]ties ( bo? classes ( salts3--,take a cry/al ( ,protosulphate ( ,iron1 &1 hav+ r$uc$ x to p[d]1 p\r a little ,nitric ,acid ^u x 9 a te/-tube4 ,on ! application ( heat1 abundance ( fumes w be giv5 (f1 & a r$ solution obta9$4 ,! ,nitric ,acid 9 ?is reaction imp>ts ,oxyg51 & conv]ts ! ,protosulphate entirely into a ,p]sulphate ( ,iron4 ,x is ?is feature1 viz4 ! t5d5cy to absorb ,oxyg51 & to pass into ! /ate ( ,p]salts1 :i* makes ! ,protosalts ( ,iron useful z develop]s4 ,!re are two ,protosalts ( ,iron commonly employ$ by ,photograph]s3 ! ,protosulphate & ! ,protonitrate ( ,iron4 a4 ,protosulphate ( ,iron4--,?is salt1 (t5 t]m$ ,copp]as or ,gre5 ,vitriol1 is an abundant sub/ance1 & us$ = a v>iety ( purposes 9 ! arts4 ,comm]cial ,sulphate ( ,iron h[ev]1 be+ prep>$ on a l>ge scale1 requires re-cry/allization to r5d] x suffici5tly pure = ,photographic purposes4 ,pure ,sulphate ( ,iron occurs 9 ! =m ( l>ge transp>5t1 prismatic cry/als1 ( a delicate gre5 col\r3 by exposure to ! air !y gradually absorb ,oxyg5 & become ru/y on ! surface4 ,solution ( ,sulphate ( ,iron1 col\rless at fir/1 aft]w>ds *anges to a r$ t9t1 & deposits a br[n p[d]2 ?is p[d] is a basic ,p]sulphate ( ,iron1 t is1 a ,p]sulphate conta9+ an excess ( ! oxide or base4 ,by ! addition ( ,sulphuric or ,acetic ,acid to ! solution1 ! =mation ( a deposit is prev5t$1 ! br[n p[d] be+ soluble 9 acid liquids4 ,! ,cry/als ( ,sulphate ( ,iron include a l>ge quantity ( wat] ( cry/allization1 a "p ( :i* !y lose by exposure to dry air4 ,by a high] temp]ature1 ! salt may be r5d]$ p]fectly anhydr\s1 9 :i* /ate x =ms a :ite p[d]4 b4 ,protonitrate ( ,iron4--,?is salt is prep>$ by d\ble decomposition betwe5 ,nitrate ( ,b>yta or ( ,lead & ,protosulphate ( ,iron4 ,x is an un/able sub/ance & cry/allizes ) great difficulty2 its aque\s solution is pale gre5 at fir/1 b v prone to decomposition1 ev5 m s ?an ! correspond+ ,sulphate ( ,iron4 ,,section ,,ii4 ,! ,r$uction ( ,salts ( ,silv] by ,develop+ ,ag5ts4 ,! g5]al !ory ( ! r$uction ( metallic oxides hav+ be5 expla9$1 x may be desirable to ent] m m9utely into ! exact nature ( ! process z appli$ to ! comp\nds ( ,silv]4 ,fir/1 ! ,r$uction ( ! ,oxide ( ,silv] w be tak51 z ! mo/ simple illu/ration2 !n t ( ,salts ( ,silv] =m$ by ,oxyg5-acids2 & la/ly1 ( ! ,*loride1 ,iodide1 & ,bromide ( ,silv] conta9+ no ,oxyg54 ,r$uction ( ,oxide ( ,silv]4--,to illu/rate ?is conv5i5tly1 ! ,oxide ( ,silv] %\ld be 9 a /ate ( solution2 wat] dissolves ,oxide ( ,silv] v sp>+ly1 b x is freely soluble 9 ,ammonia1 =m+ ! liquid kn[n z ,ammonio-,nitrate ( ,silv]4 ,if1 !re=e1 a little ( ! ,ammonio-,nitrate ( ,silv] be plac$ 9 a te/-tube1 & solution ( ,sulphate ( ,iron be add$ to x1 imm$iately x becomes discol\r$1 & a deposit settles to ! bottom4 ,?is deposit is metallic ,silv]1 produc$ by ! r$uc+ ag5t appropriat+ to itself ! ,oxyg5 previ\sly comb9$ ) ! metal4 ,z metallic ,silv] does n dissolve 9 ,ammonia1 ! liquid becomes turbid1 & ! metal subsides 9 ! =m ( a bulky precipitate4 ,r$uction ( ! ,oxyacid ,salts ( ,silv]4--,! t]m ,oxyacid includes ^? salts :i* conta9 ! ,oxide ( ,silv] intimately comb9$ ) ,oxyg5-acids2 z e4 g4 ! ,nitrate ( ,silv]1 ! ,sulphate1 ! ,acetate ( ,silv]1 etc4 ,^! salts1 soluble 9 wat]1 are r$uc$ by develop+ ag5ts 9 ! same mann] z ,oxide ( ,silv]1 b m sl[ly4 ,! pres5ce ( an acid unit$ ) ! base is a h9drance to ! process & t5ds to keep ! oxide 9 solution1 especially :5 t acid is p[]ful 9 its aff9ities4 ,to illu/rate ! effect ( ! acid con/itu5t ( ! salt 9 ret>d+ r$uction1 take two te/-tubes1 ! "o conta9+ ,ammonio-,nitrate1 & ! o!r ord9>y ,nitrate ( ,silv]--a s+le drop ( solution ( ,sulphate ( ,iron add$ to ea* w indicate an evid5t diff]5ce 9 ! rapidity ( deposition4 ,! precipitate ( metallic ,silv] obta9$ by ! action ( r$uc+ ag5ts ^u ! ,nitrate1 v>ies mu* 9 col\r & 9 g5]al appe>ance4 ,if ,gallic or ,pyrogallic ,acid be employ$1 x is a black p[d]2#h :il/ ! salts ( ,iron1 & especially ! same ) free ,nitric ,acid add$1 produce a sp>kl+ precipitate1 resembl+ :at is t]m$ fro/$ silv]4 ,grape ,sug> & _m ( ! ess5tial oils1 su* z ! ,oil ( ,cloves1 etc41 sep>ate ! metal f ,ammonio-,nitrate ( ,silv] 9 ! =m ( a brilliant mirror film1 & are (t5 employ$ 9 silv]+ glass4 #h ,silv] precipitat$ by ,gallic or ,pyrogallic ,acid does n appe> to be free f organic matt]1 & probably conta9s also a small proportion ( ,oxyg54 ,9 rem>k+ ^u ^! peculi>ities 9 ! molecul> condition ( precipitat$ ,silv]1 x %\ld be obs]v$ t ! appe>ance ( a metal :il/ 9 mass is no indication ( its col\r :5 9 ! /ate ( f9e p[d]4 ,plat9um & ,iron1 bo? bright metals1 & susceptible ( a high poli%1 are dull & int5sely black :5 9 a f9e /ate ( division2 ,gold is ( a purple or yell[i% br[n2 ,m]cury a dirty grey4 ,r$uction ( ! ,hydracid ,salts ( ,silv]4--,by ! t]m ,hydracid is meant ,salts ( ,silv] :i* conta9 no ,oxyg5 or ,oxyg5-acids1 b simply elem5ts l ,*lor9e or ,iod9e comb9$ ) ,silv]4 ,^! elem5ts are *>act]iz$ by =m+ acids ) ,hydrog51 :i* acids are h5ce call$ ,hydracids4 ,hydro*loric ,acid 7,h,cl7 is an example2 s also is ,hydriodic ,acid 7,,hi74 ,! r$uction ( ! ,hydracid ,salts requires to be discuss$ sep>ately1 because x is evid5tly diff]5t f t already describ$2 ! r$uc+ ag5t t5d+ only to absorb ,oxyg51 :i* is n pres5t 9 ^! salts4 ,! explanation is z foll[s3 ,:5 a ,*loride ( a noble metal is r$uc$ by a develop]1 an atom ( wat]1 compos$ ( ,oxyg5 & ,hydrog51 takes a "p 9 ! reaction4 ,! ,oxyg5 ( ! wat] passes to ! develop]1 ! ,hydrog5 to ! ,*lor9e4 ,to illu/rate ?is1 take a solution ( ,*loride ( ,gold1 & add to x a little ,sulphate ( ,iron4 ,a yell[ deposit ( metallic ,gold soon =ms1 & ! sup]natant liquid is f\nd1 by te/+1 to be acid f free ,hydro*loric ,acid4 ,! foll[+ simple diagram1 9 :i* h[ev] ! numb] ( ! atoms conc]n$ is omitt$1 may assi/ ! compreh5sion ( ! *ange4 ,illu/ration3 ,comp\nd ,atom ( ,comp\nd ,atom ,atom ( ,*loride ( ,gold4 ( ,wat]4 ,sulphate ( ,iron4 ,! symbol ,au repres5ts ,gold1 ,cl ,*lor9e1 ,h ,hydrog51 & ,o ,oxyg54 ,obs]ve t ! molecules ,h & ,o sep>ate f ea* o!r & pass 9 opposite directions3 ! latt] unites ) ! ,sulphate ( ,iron2 ! =m] meets ,cl1 & produces ,hydro*loric ,acid 7,h,cl71 :il/ ! atom ( ,gold is left alone4 ,h5ce !re is no !oretical difficulty 9 suppos+ a r$uction ( ,iodide ( ,silv] by a develop]1 if we associate ) ! ,iodide an atom ( wat] to furni% ! ,oxyg54 ,unless ! s5sitive plate h[ev] has be5 expos$ to ! light1 ! r$uction does n readily take place2 nor c x be produc$ "u any circum/ances1 ) or )\t light1 :5 ! :ole ( ! free ,nitrate ( ,silv] has be5 wa%$ away f ! plate4 ,pure ,iodide ( ,silv] is !re=e unaffect$ by a develop]1 & ! comp\nd :i* black5s on ! application ( ,sulphate ( ,iron or ,pyrogallic acid is an ,iodide ) excess ( ,nitrate ( ,silv]4 ,illu/ration3 ,comp\nd ,atom ( ,comp\nd ,atom ( ,atom ( ,iodide ( ,silv]4 ,nitrate ( ,silv]4 ,sulphate ( ,iron4 ,! mode 9 :i* a ,salt ( ,silv]1 su* z ! ,nitrate1 soluble 9 wat]1 may act 9 facilitat+ ! r$uction ( ,iodide ( ,silv]1 is %[n 9 ! prec$+ diagram1 :i* corresponds closely ) ! la/4 ,notice t ! comp\nd atom ( ,nitrate ( ,silv] conta9s a molecule ( ,oxyg5 = ! develop]1 "o ( ,silv] 7,ag7 = ! sep>at$ ,iod9e1 & an atom ( ,nitric ,acid 7,,no#e71 :i* is lib]at$1 & takes no fur!r "p 9 ! *ange4 ,! *a9 ( *emical aff9ities is m complete 9 ?is diagram ?an 9 ! la/1 :]e an atom ( wat] only 0 pres5t1 ! aff9ity ( ,iod9e = ,silv] be+ great] ?an t ( ,iod9e = ,hydrog54 ,h5ce x is possible t an excess ( ,nitrate ( ,silv] may1 by furni%+ an elem5t>y basis = :i* ,iod9e has an attraction1 assi/ 9 draw+ (f t elem5t1 s to speak1 f ! orig9al p>ticle ( ,iodide ( ,silv] t\*$ by light4#i #i ,! read] mu/ n suppose f ! rem>ks :i* h be5 made 9 ?is ,section t images obta9$ by developm5t consi/ inv>iably ( pure metallic ,silv]4 ,x c be %[n t su* is n ! case1--t ! process ( r$uction is 9 _m cases susp5d$ :5 a "p only ( ! ,oxyg5 has be5 remov$2 & h5ce results a subsalt simil> to t produc$ by ! direct action ( light ^u organic comp\nds ( ,silv]1 & diff]+ 9 prop]ties f metallic ,silv]4 ,= fur!r p>ticul>s see ! ,au?or's ,photographic rese>*es 9 ! eigh? ,*apt]4 ,,section ,,iii4 ,! =mation & developm5t ( ! ,lat5t ,image4 ,x 0 %[n 9 ! second ,*apt] t ! cont9u$ action ( :ite light ^u c]ta9 ( ! ,salts ( ,silv] result$ 9 ! sep>ation ( elem5ts l ,*lor9e & ,oxyg5 & ! p>tial r$uction ( ! comp\nd4 ,we h also se5 t bodies possess+ aff9ity = ,oxyg51 su* z ,sulphate ( ,iron & ,pyrogallic ,acid1 t5d to produce a simil> effect2 act+ 9 "s cases ) great en]gy & precipitat+ metallic ,silv] 9 a pure /ate4 ,9 =m+ an extemporane\s !ory on ! production ( ! lat5t image 9 ! ,cam]a1 x w\ld !re=e be natural to suppose t ! process consi/$ 9 sett+ up a r$uc+ action ^u ! s5sitive surface by means ( light1 aft]w>ds to be cont9u$ by ! application ( ! develop+ solution4 ,?is idea is to a c]ta9 ext5t correct1 b x requires "s explanation4 ,! effects produc$ by ! light & ! develop] are n s precisely simil> t ! "o ag5cy c always be sub/itut$ = ! o!r3 an insuffici5t exposure 9 ! ,cam]a _c be rem$i$ by prolong+ ! developm5t ( ! image4 ,9 ! ,photographic processes on pap] x is inde$ f\nd t a c]ta9 latitude may be all[$2 b1 z a rule1 x %\ld be /at$ t a def9ite "t is occupi$ 9 ! =mation ( ! invisible image1 :i* may n be %ort5$ or ext5d$ beyond its prop] limits ) impunity4 ,!re is a maximum po9t beyond :i* no advance is made2 h5ce if ! plate be n !n remov$ f ! ,cam]a1 ^? portions ( ! image =m$ by ! brighte/ lights are spe$ily ov]tak5 by ! half tones1 s t1 on develop+1 an image appe>s )\t t contra/ betwe5 lights & %ad[s :i* is ess5tial to ! arti/ic effect4 ,on ! o!r h&1 9 a case ( insuffici5t exposure1 ! feeble rays ( light n hav+ be5 all[$ "t to impress ! plate1 ! half %ad[s _c be br\ght out on subsequ5t treatm5t ) ! develop+ ag5t4 ,a c>eful /udy ( ! ph5om5a involv$ 9 ?is "p ( ! process _c fail to %[ t ! ray ( ,light det]m9es a molecul> *ange ( "s k9d 9 ! p>ticles ( ,iodide ( ,silv] =m+ ! s5sitive surface4 ,?is *ange is n ( a nature to alt] ! composition or ! *emical prop]ties ( ! salt4 ,! ,iod9e does n leave ! surface1 or !re w\ld be a diff]5ce 9 ! appe>ance ( ! film1 or 9 its solubility 9 ,hyposulphite ( ,soda4 ,! foll[+ diagrams may p]haps be useful 9 me*anically illu/rat+ :at is meant by a molecul> *ange4 ,fig4 #a repres5ts a comp\nd molecule ( ,iodide ( ,silv]1 ! compon5t atoms ( :i* are closely associat$4 ,fig4 #b4 ,! same aft] ! action ( a di/urb+ =ce4 ,! simple molecules h n altoge!r sep>at$1 b !y are prep>$ to d s1 t\*+ only at a s+le po9t4 ,illu/ration3 ,fig4 #a4 ,illu/ration3 ,fig4 #b4 ,n[ ! effect produc$ on ?is comb9ation by a develop] is und]/ood1 if we suppose t 9 ! fir/ case ! aff9ity ( ! ,iod9e = ,silv] is too great to all[ ( its sep>ation2 b 9 ! second1 ?is aff9ity hav+ be5 loos5$1 ! /ructure gives way1 & metallic ,silv] is ! result4 ,?is hypo!sis has ! m]it ( simplicity1 & is n oppos$ to kn[n facts2 x may !re=e = ! pres5t be receiv$4 ,! po9t h[ev] on :i* a d\bt mu/ re/ is--:e!r ! molecul> di/urbance produc$ by light ^u ,iodide ( ,silv] leads to a r$uction ( t ,salt by ! develop]4 ,no image c be produc$ on ! application ( ,pyrogallic ,acid unless ! p>ticles ( ,iodide are 9 contact ) ,nitrate ( ,silv]2 & h5ce x may be ! ,nitrate & n ! ,iodide :i* is r$uc$--t is1 ! impress$ molecule ( ,iodide may det]m9e ! decomposition ( a contigu\s p>ticle ( ,nitrate1 itself rema9+ un*ang$4 ,?is view is support$ to "s ext5t by ,mos]'s exp]im5ts1 %ortly to be quot$2 & also by ! fact t ! delicate image fir/ =m$ c be int5sifi$ by treat+ x ) a mixture ( ! develop+ solution & ,nitrate ( ,silv]1 ev5 aft] ! ,iodide has be5 remov$ by a fix+ ag5t4 ,! foll[+ exp]im5t w s]ve to illu/rate ?is4-- ,take a s5sitive ,collodion plate1 & hav+ impress$ an invisible image ^u x by a prop] exposure 9 ! ,cam]a1 remove x to ! d>k room1 & p\r ov] x ! solution ( ,pyrogallic ,acid4 ,:5 ! picture has fully appe>$1 /op ! action by wa%+ ! plate ) wat]1 & remove ! unalt]$ ,iodide ( ,silv] by ,cyanide ( ,potassium4 ,an exam9ation ( ! image at ?is /age w %[ t x is p]fect 9 ! details1 b pale & transluc5t4 ,! plate is !n to be tak5 back aga9 to ! d>k room & treat$ ) fre% ,pyrogallic ,acid1 to :i* ,nitrate ( ,silv] has be5 add$2 imm$iately ! picture becomes mu* black]1 & cont9ues to d>k51 ev5 to complete opacity1 if ! supply ( ,nitrate be kept up4 ,n[ 9 ?is exp]im5t x is evid5t t ! additional deposit ^u ! image is produc$ f ! ,nitrate ( ,silv]1 ! :ole ( ! ,iodide hav+ be5 previ\sly remov$4 ,obs]ve also1 t x =ms only ^u ! image1 & n ^u ! transp>5t p>ts ( ! plate4 ,ev5 if ! ,iodide1 unt\*$ by light1 be all[$ to rema91 ! same rule holds good2--! ,pyrogallic ,acid & ,nitrate ( ,silv] react ^u ea* o!r & produce a metallic deposit2 ?is deposit h[ev] has no aff9ity = ! unalt]$ ,iodide ^u ! "p ( ! plate correspond+ to ! %ad[s ( ! picture1 b atta*es itself 9 pref]5ce to ! ,iodide already black5$ by light4 ,?is second /age ( ! developm5t1 by :i* a feeble image may be /r5g!n$ & r5d]$ m opaque1 is sometimes t]m$ developm5t by precipitation1 & %\ld be correctly und]/ood by ! practical op]ator4 ,rese>*es ( ,m4 ,mos]4--,! pap]s ( ,m4 ,ludwig ,mos] ',on ! ,=mation & ,developm5t ( ,invisible ,images1' publi%$ 9 #ahdb1 expla9 s cle>ly _m rem>kable ph5om5a ( occasional occurr5ce 9 ! ,collodion & pap] processes1 t no apology ne$ be (f]$ = ref]r+ to !m some:at at l5g?4 ,8 fir/ proposition may be /at$ ?us3--,if a poli%$ surface has be5 t\*$ 9 p>ticul> p>ts by anybody1 x acquires ! prop]ty ( precipitat+ c]ta9 vap\rs on ^! spots diff]5tly to :at x does on ! o!r unt\*$ p>ts4 ,to illu/rate ?is1 take a ?9 plate ( metal1 hav+ *>act]s excis$2 w>m x g5tly1 & lay x ^u ! surface ( a clean mirror glass = a few m9utes3 !n remove1 all[ to cool1 & brea! ^u ! glass1 :5 ! outl9es ( ! device w be di/9ctly se54 ,a plate ( poli%$ ,silv] may be sub/itut$ = ! glass1 & 9 place ( develop+ ! image by ! brea?1 x may be br\ght out by ,m]curial vap\r4 ,! second proposition ( ,m4 ,mos] is z foll[s3--,light acts on bodies1 & its influ5ce may be te/$ by vap\rs t adh]e to ! sub/ance4--,a plate ( mirror glass is expos$ 9 ! ,cam]a to a bright & int5se light2 x is !n remov$ & brea!d ^u1 :5 an image be=e invisible w be develop$1 ! brea? settl+ mo/ /rongly ^u ! p>ts :]e ! light has act$4 ,a plate ( poli%$ ,silv] may be us$ z be=e in/ead ( glass1 ! vap\r ( ,m]cury or ( wat] be+ employ$ to develope ! image4 ,an iodiz$ ,silv] plate is /ill m s5sitive to ! influ5ce ( ! light1 & receives a v %>p & p]fect impression "u ! action ( ! ,m]cury4 ,x seems !re=e f ^! exp]im5ts & o!rs n quot$1 t ! surfaces ( v>i\s bodies are capable ( be+ modifi$ by contact ) ea* o!r1 or by contact ) a ray ( light1 9 su* a way z to imp>t an aff9ity = a vap\r2 & fur!r1 t _m ( ! ,salts ( ,silv] are 9 ! li/ ( sub/ances admitt+ ( su* modification4 ,b x is also evid5t t ! same condition ( surface :i* causes a vap\r to settle 9 a peculi> mann] also affects ! behavi\r ( ! ,silv] ,salt :5 treat$ ) a r$uc+ ag5t4 ,?us1 if a clean glass plate be t\*$ 9 c]ta9 spots by ! w>m f+]1 ! impression soon disappe>s1 b is aga9 se5 on brea?+ ^u ! glass2 & if ?is same plate be coat$ ) a v delicate lay] ( ,iodiz$ ,collodion & pass$ ?r\gh ! ,nitrate ba?1 ! solution ( ,pyrogallic acid w commonly produce a well-def9$ outl9e ( ! figure ev5 be=e ! plate has be5 expos$ to ! light4 ,?is exp]im5t1 al?\gh x does n inv>iably succe$1 is nev]!less an in/ructive "o1 & %[s ! necessity ( clean+ ! plates us$ 9 ,photography ) c>e4 ,if !re be any irregul>ity 9 ! mann] 9 :i* ! brea? settles ^u ! glass :5 x is brea!d on1 a condition ( surface exi/s at t po9t :i* w probably s modify ! lay] ( ,iodide ( ,silv]1 t ! action ( ! develop+ fluid w be 9 "s way int]f]$ )4 ,"o m rem>kable fact obs]v$ by ,m4 ,mos] may be quot$4 ,he f9ds t ! action ( light ^u ! ,dagu]reotype plate is ( an alt]nat+ k9d3 x fir/ gives an aff9ity = ,m]cury1 & !n removes x4 ,if light acts on ,iodide ( ,silv]1 he says1 x imp>ts to x ! p[] ( cond5s+ m]curial vap\rs2 b if x acts beyond a c]ta9 "t1 x !n dim9i%es ?is p[] & at l5g? takes x away altoge!r4 ,?is is precisely 9 accordance ) ph5om5a obs]v$ also 9 ! ,collodion process1 :]e ! deposit ( metallic ,silv] is sometime less m>k$ ?an usual if ! plate has be5 expos$ 9 ! ,cam]a beyond ! prop] p]iod ( "t4 ,a curi\s p]v]sion ( ! develop+ process is occasionally met )1 9 :i* on ! application ( ! ,pyrogallic ,acid1 ! deposit ( ,silv] takes place ^u ! %ad[s ( ! picture1 & n ^u ! lights2 h5ce on view+ ! image by transmitt$ light1 ! usual appe>ance is rev]s$4 ,?is may p]haps be expla9$ by an alt]nat+ action ( ! light z above sugge/$4 ,a ph5om5on at fir/ sight ev5 m rem>kable has occurr$1 9 :i*1 on develop+ ! plate1 two images />t out in/ead ( "o4 ,! second>y image 9 su* a case is probably ! rema9s ( a previ\s impression :i*1 al?\gh app>5tly remov$ by wa%+1 _h nev]!less modifi$ ! surface ( ! glass s z to affect ! lay] ( ,iodide ( ,silv]2 & if ! glass 7 brea!d ^u be=e aga9 coat+ x ) ,collodion1 !re is e reason to suppose t ! outl9es ( ! accid5tal image w\ld be se54#aj #aj ,s9ce writ+ ! above1 ! ,au?or has p]us$ ) pleasure a pap] by ,mr4 ,grove on ! production ( lat5t images by electricity1 ) a mode ( fix+ !m4 ,9 ! exp]im5ts describ$1 a plate ( glass1 electriz$ 9 c]ta9 portions only1 0 brea!d ^u1 or expos$ to ! fumes ( ,hydr(luoric ,acid4 ,9 ei!r case ! vap\r settl$ exclusively ^u ! non-electrical "p ( ! glass1 ?us develop+ a lat5t image4 ,:5 ! plate 0 fir/ submitt$ to electrization1 & !n coat$ ) ,iodide ( ,silv] ^u ,collodion1 & expos$ to light1--solution ( ,pyrogallic ,acid produc$ a r$uction ( ,silv] only ^u ! p>ts ( ! glass correspond+ to ^? on :i* ! brea? settl$ 9 ! previ\s exp]im5t2 ?us indicat+ t ! electricity neutraliz$ ! effect ( light ^u ! s5sitive ,iodide ( ,silv]4 ,,*apt] ,,iv4 ,,on ,,fix+ ,,! ,,photographic ,,image4 ,a s5sitive lay] ( ,*loride or ,iodide ( ,silv] on :i* an image has be5 =m$1 ei!r ) or )\t ! aid ( a develop+ ag5t1 mu/ pass ?r\gh fur!r treatm5t 9 ord] to r5d] x inde/ructible by diffus$ light4 ,x is true t ! image itself is suffici5tly p]man5t1 & _c be said1 9 correct language1 to ne$ fix+2 b ! un*ang$ ,silv] ,salt :i* surr\nds x1 be+ /ill s5sitive to light1 t5ds to be decompos$ 9 its turn1 & s ! picture is lo/4 ,x is !re=e necess>y to remove ?is salt by apply+ "s *emical ag5t capable ( dissolv+ x4 ,! li/ ( solv5ts ( ,*loride & ,iodide ( ,silv] has be5 giv5 9 ,*apt] ,,ii41 b "s are bett] adapt$ = fix+ ?an o!rs4 ,9 ord] t any body may be employ$ ) success z a fix+ ag5t1 x is requir$ n only t x %\ld dissolve un*ang$ ,*loride or ,iodide ( ,silv]1 b t x %\ld produce no injuri\s effect ^u ! same salts r$uc$ by light4 ,?is solv5t action ^u ! image1 z well z ^u ! p>ts :i* surr\nd x1 is mo/ liable to happ5 :5 ! ag5cy ( light alone1 )\t a develop]1 has be5 employ$4 ,9 t case ! d>k5$ surface1 n be+ r$uc$ p]fectly to ! metallic /ate1 rema9s soluble to a c]ta9 ext5t 9 ! fix+ liquid4 ,,*emi/ry ,,( ,,! ,,v>i\s ,,fix+ ,,ag5ts4 ,! foll[+ w be m5tion$3--,ammonia--,alkal9e ,*lorides--,alkal9e ,iodides--,alkal9e ,hyposulphite--,alkal9e ,cyanides4 ,,ammonia4 ,! prop]ties ( ! alkal9e liquid ,ammonia are giv5 9 ,"p ,,iii4 ,ammonia dissolves ,*loride ( ,silv] readily1 b n ,iodide ( ,silv]3 h5ce its use is necess>ily conf9$ to ! pap] pro(s ^u ,*loride ( ,silv]4 ,ev5 ^! h[ev] _c advantage\sly be fix$ 9 ,ammonia unless a deposit ( ,gold has be5 previ\sly produc$ ^u ! surface by a process ( ton+1 pres5tly to be expla9$3 a peculi> & unpleasant r$ t9t is always caus$ by ,ammonia act+ ^u ! d>k5$ mat]ial ( a sun picture z x comes f ! pr9t+-frame3 b ?is is obviat$ by ! employm5t ( ! ,gold4 ,,alkal9e ,,*lorides1 ,,iodides1 ,,& ,,bromides4 ,! ,*lorides ( ,potassium1 ,ammonium1 & ,sodium possess ! prop]ty ( dissolv+ a small portion ( ,*loride ( ,silv]4 ,9 ! act ( solution a d\ble salt is =m$2 t is1 a comp\nd ( ,*loride ( ,sodium ) ,*loride ( ,silv]1 :i* may be cry/alliz$ out by all[+ ! liquid to evaporate spontane\sly4 ,! e>li] ,photograph]s employ$ a saturat$ solution ( common ,salt = fix+ pap] pr9ts2 b ! fix+ action ( ! ,alkal9e ,*lorides is sl[ & imp]fect1 & _! use may n[ be said to be obsolete4 ,! ,iodide & ,bromide ( ,potassium h bo? be5 us$ z fix+ ag5ts4 ,!y dissolve ,iodide ( ,silv]1 =m+ ) x a d\ble salt 9 ! mann] be=e describ$4 ,x is important to rem>k 9 ! solution ( ! insoluble ,silv] ,salts by ,alkal9e ,*lorides1 ,iodides1 etc41 t ! am\nt dissolv$ is n 9 proportion to ! quantity ( ! solv5t1 b to ! degree ( conc5tration ( its aque\s solution4 ,?is is n usual ) solv5ts :i* act by ent]+ into *emical comb9ation ) ! sub/ance dissolv$4 ,commonly a giv5 weight ( ! "o salt dissolves a giv5 weight ( ! o!r1 indep5d5t ( ! am\nt ( wat] pres5t4 ,! peculi>ity 9 ! case be=e u dep5ds ^u ! fact t ! d\ble salt =m$ is decompos$ by a l>ge quantity ( wat]4 ,h5ce x is a saturat$ solution ( ,*loride ( ,sodium :i* possesses ! greate/ p[] ( fix+ pap] pr9ts2 & ) ! ,bromide or ,iodide ( ,potassium ! same rule holds good--! /rong] ! solution ! m ,iodide ( ,silv] w be tak5 up4 ,! addition ( wat] produces milk9ess & a deposit ( ! silv] ,salt previ\sly dissolv$4 ,,alkal9e ,,hyposulphites4 ,hyposulphur\s ,acid is "o ( ! ,oxides ( ,sulphur4 ,x is1 z its "n implies1 ( an acid nature1 & takes its place ^u ! li/ imm$iately bel[ ,sulphur\s ,acid 71 "u74 ,! ,hyposulphite ( ,soda commonly employ$ by ,photograph]s is a neutral comb9ation ( ,hyposulphur\s ,acid & ! alkali ,soda4 ,x is select$ z be+ m economical 9 prep>ation ?an any o!r ,hyposulphite adapt$ = fix+4 ,hyposulphite ( ,soda occurs 9 ! =m ( l>ge transluc5t gr\ps ( cry/als1 :i* include five atoms ( wat]4 ,^! cry/als are soluble 9 wat] almo/ to any ext5t1 ! solution be+ att5d$ ) ! production ( cold2 !y h a nause\s & bitt] ta/e4 ,9 ! solution ( ,silv] comp\nds by ,hyposulphite ( ,soda a d\ble decomposition always takes place2 ?us3-- ,hyposulphite ( ,soda ,*loride ( ,silv] ,hyposulphite ( ,silv] ,*loride ( ,sodium4 ,! ,hyposulphite ( ,silv] ) an excess ( ,hyposulphite ( ,soda =ms a soluble d\ble salt1 :i* may be cry/alliz$ out by evaporat+ ! solution4 ,x possesses an int5sely sweet ta/e1 & conta9s "o atom ( ,hyposulphite ( ,silv]1 *emically comb9$ ) two ( ,hyposulphite ( ,soda4 ,9 addition to ?is !re is a second d\ble ,salt1 diff]+ f ! fir/ 9 be+ v sp>+ly soluble 9 wat]4 ,x is =m$ by act+ ^u ,*loride ( ,silv] ) a solution ( ,hyposulphite ( ,soda already saturat$1 or ne>ly s1 ) ,silv] ,salts2 & conta9s s+le atoms ( ea* con/itu5t4 ,! fact t ! ,silv] conta9$ 9 an ord9>y fix+ ,ba? is pres5t 9 ! /ate ( ,hyposulphite mu/ be borne 9 m9d1 because ?is salt is liable to und]go peculi> *emical *anges1 z w be bett] %[n 9 ,*apt] ,,viii4 ,iodide ( ,silv] is dissolv$ by ,hyposulphite ( ,soda m sl[ly ?an ,*loride ( ,silv]1 & ! am\nt ev5tually tak5 up is less4 ,?is is expla9$ z foll[s3-- ,dur+ ! solution ( ,iodide ( ,silv]1 ,iodide ( ,sodium is =m$1 & ?is alkal9e ,iodide has a prejudicial effect ^u ! cont9uance ( ! process4 ,*loride ( ,sodium has n ! same action1 nei!r has ,bromide ( ,sodium1 consequ5tly ! correspond+ ,silv] ,salts dissolve to a great] ext5t ?an ! ,iodide4 ,,alkal9e ,,cyanides4 ,! *emi/ry ( ,cyanog5 is sket*$ 9 ,"p ,,iii4 ,! ,cyanide ( ,potassium is ! salt mo/ frequ5tly employ$ 9 fix+4 ,x occurs 9 comm]ce 9 ! =m ( fus$ lumps ( consid]able size4 ,9 ?is /ate x is usually contam9at$ ) a l>ge p]c5tage ( ,c>bonate ( ,pota%1 am\nt+ 9 "s cases to m ?an half its weight4 ,by boil+ 9 pro( ,_s ! ,cyanide may be extract$ & cry/alliz$1 b ?is op]ation is sc>cely requir$ z f> z its use 9 ,photography is conc]n$4 ,cyanide ( ,potassium absorbs moi/ure on exposure to ! air4 ,x is v soluble 9 wat]1 b ! solution decomposes on keep+2 *ang+ 9 col\r & evolv+ ! od\r ( ,prussic ,acid1 :i* is a ,cyanide ( ,hydrog54 ,cyanide ( ,potassium is highly poison\s1 & mu/ be us$ ) caution4 ,solution ( ,cyanide ( ,potassium is a mo/ en]getic ag5t 9 dissolv+ ! insoluble ,silv] ,salts3 f> m s1 9 proportion to ! quantity us$1 ?an ! ,hyposulphite ( ,soda4 ,! ,salts are 9 all cases conv]t$ into ,cyanides1 & exi/ 9 ! solution 9 ! =m ( soluble d\ble ,salts1 :i*1 unlike ! d\ble ,iodides1 are n affect$ by dilution ) wat]4 ,cyanide ( ,potassium is unadapt$ = fix+ positive pro(s ^u ,*loride ( ,silv]2 & ev5 :5 a develop] has be5 us$1 unless ! solution is tol]ably dilute1 x is apt to attack ! image & dissolve x4 ,,*apt] ,v4 ,,on ,,! ,,nature ,,& ,,prop]ties ,,( ,,light4 ,! pres5t ,*apt] is devot$ to a discussion ( ! m rem>kable prop]ties ( ,light2 ! object be+ to select c]ta9 prom95t po9ts1 & to /ate !m z cle>ly z possible1 ref]r+1 = in=mation ( a m complete k9d1 to ackn[l$g$ works on ! subject ( ,optics4 ,! ,*apt] w be divid$ into five ,sections3--fir/1 ! comp\nd nature ( ,light2 second1 ! laws ( refraction ( ,light2 ?ird1 ! con/ruction ( ,l5ses & ( ! ,cam]a2 f\r?1 ! ,photographic action ( col\r$ ,light2 fif?1 on ,b9ocul> ,vision & ! ,/]eoscope4 ,,section ,i4 ,! ,comp\nd ,nature ( ,light4 ,! ideas ent]ta9$ on ! subject ( ,light1 be=e ! "t ( ,sir ,isaac ,newton1 7 vague & unsatisfactory4 ,x 0 %[n by t em95t philosoph]1 t a ray ( sunlight 0 n homog5e\s1 z _h be5 suppos$1 b consi/$ ( sev]al rays ( vivid col\rs1 unit$ & int]m+l$4 ,?is fact may be demon/rat$ by ?r[+ a p5cil ( ,sunlight ^u "o angle ( a prism1 & receiv+ ! oblong image1 s =m$1 ^u a :ite scre54 ,! space illum9at$ & col\r$ by a p5cil ( rays analyz$ 9 ?is way is call$ ! ,sol> ,spectrum4 ,! action ( a prism 9 decompos+ :ite light w be m fully expla9$ 9 ! next ,section4 ,at pres5t we notice only t sev5 pr9cipal col\rs may be di/+ui%$ 9 ! ,sol> ,spectrum1 viz4 r$1 orange1 yell[1 gre51 blue1 indigo1 & violet4 ,sir ,david ,brew/] has made obs]vations :i* lead him to suppose t ! prim>y col\rs are 9 reality b ?ree 9 numb]1 viz4 r$1 yell[1 & blue1 & t ! o!rs are comp\nd1 be+ produc$ by two or m ( ^! ov]lapp+ ea* o!r2 ?us ! r$ & yell[ spaces int]m+l$ con/itute orange2 ! yell[ & blue spaces1 gre54 ,illu/ration ,! composition ( :ite light f ! sev5 prismatic col\rs may be r\ghly prov$ by pa9t+ !m on ! face ( a :eel1 & caus+ x to rotate rapidly2 ?is bl5ds !m toge!r1 & a sort ( greyi%-:ite is ! result4 ,! :ite is imp]fect1 because ! col\rs employ$ _c possibly be obta9$ ( ! prop] t9ts or laid on 9 ! exact proportions4 ,! decomposition ( light is effect$ 9 o!r ways besides t already giv53--- ,fir/1 by reflection =m ! surfaces ( col\r$ bodies4 ,all sub/ances ?r[ (f rays ( light1 :i* imp+e ^u ! ret9a ( ! eye & produce ! ph5om5a ( vision4 ,col\r is caus$ by a portion only1 & n ! :ole1 ( ! elem5t>y rays1 be+ project$ 9 ?is way4 ,surfaces t]m$ :ite reflect all ! rays2 col\r$ surfaces absorb "s & reflect o!rs3 ?us r$ sub/ances reflect only r$ rays1 yell[ sub/ances1 yell[ rays1 etc1 ! ray :i* is reflect$ 9 all cases decid+ ! col\r ( ! sub/ance4 ,secondly1 light may be decompos$ by transmission ?r\gh m$ia :i* are transp>5t to c]ta9 rays1 b opaque to o!rs4 ,ord9>y transp>5t glass all[s all ! rays con/itut+ :ite light to pass2 b by ! addition ( c]ta9 metallic oxides to x :il/ 9 a /ate ( fusion1 its prop]ties are modifi$1 & x becomes col\r$4 ,glass /a9$ by ,oxide ( ,cobalt is p]meable only to blue rays4 ,oxide ( ,silv] imp>ts a pure yell[ t9t2 ,oxide ( ,gold or ,suboxide ( ,copp] a ruby r$1 etc4 ,,division ,,( ,,! ,,elem5t>y ,,rays ,,( ,,:ite ,,light ,,into ,,lum9\s1 ,,heat-,,produc+1 ,,& ,,*emical4 ,,rays4 ,! ag5cy ( ,light produces a v>iety ( di/9ct effects ^u ! bodies :i* surr\nd u4 ,^! may be class$ toge!r z ! prop]ties ( light4 ,!y are ( ?ree k9ds--! ph5om5a ( col\r & vision1 ( heat1 & ( *emical action4 ,by resolv+ :ite light into its con/itu5t rays1 we f9d t ^! prop]ties are associat$ ea* "o ) c]ta9 ( ! elem5t>y col\rs4 ,! yell[ is decid$ly ! mo/ lum9\s ray4 ,on exam9+ ! ,sol> ,spectrum1 x is se5 t ! brighte/ "p is t occupi$ by ! yell[1 & t ! light dim9i%es rapidly on ei!r side4 ,s aga91 rooms glaz$ ) yell[ glass always appe> abundantly illum9at$1 :il/ ! effect ( r$ or blue glass is d>k & sombre4 ,! yell[ col\r !re=e con/itutes t portion ( :ite light by :i* surr\nd+ objects are r5d]$ visible2 x is ess5tially ! visual ray4 ,! heat+ prop]ties ( ! sunlight reside pr9cipally 9 ! r$ ray1 z is %[n by ! expansion ( a m]curial !rmomet] plac$ 9 t "p ( ! spectrum4 ,! *emical action ( light corresponds m to ! indigo & violet rays1 & is want+1 z reg>ds its influ5ce ^u ,iodide ( ,silv]1 bo? 9 ! r$ & yell[4 ,/rictly speak+ h[ev] x _c be localiz$ 9 ei!r ( ! col\r$ spaces1 z w be m fully %[n 9 ! ,f\r? ,section ( ?is ,*apt]1 to :i* ! read] is ref]r$4 ,,section ,,ii4 ,! ,refraction ( ,light4 ,a ray ( light1 9 its passage ?r\gh any transp>5t m$ium1 travels 9 a /raight l9e z long z ! d5sity ( ! m$ium cont9ues un*ang$4 ,b if ! d5sity v>ies1 becom+ ei!r great] or less1 !n ! ray is refract$1 or b5t out ( ! c\rse :i* x orig9ally pursu$4 ,! degree to :i* ! refraction or b5d+ takes place dep5ds ^u ! nature ( ! new m$ium1 & 9 p>ticul> ^u its d5sity z comp>$ ) t ( ! m$ium :i* ! ray _h previ\sly trav]s$4 ,h5ce ,wat] refracts light m p[]fully ?an ,air1 & ,glass m s ?an ,wat]4 ,! foll[+ diagram illu/rates ! refraction ( a ray ( light4 ,illu/ration ,! dott$ l9e is drawn p]p5dicul>ly to ! surface1 & x is se5 t ! ray ( light on ent]+ is b5t t[>ds ?is l9e4 ,on em]g+1 on ! o!r h&1 x is b5t to an equal ext5t away f ! p]p5dicul>1 s t x proce$s 9 a c\rse p>allel to1 b n co9cid5t )1 its orig9al direction4 ,if we suppose ! new m$ium1 9 place ( be+ m d5se ?an ! old1 to be less d5se1 !n ! conditions are exactly rev]s$1--! ray is b5t away f ! p]p5dicul> on ent]+1 & t[>ds x on leav+4 ,x mu/ be obs]v$ t ! laws ( refraction apply only to rays ( light :i* fall ^u ! m$ium at an angle3 if !y ent] p]p5dicul>ly--9 ! direction ( ! dott$ l9es 9 ! la/ figure--!y pass /raight ?r\gh )\t suff]+ refraction4 ,notice also1 t x is at ! surfaces ( bodies t ! deflect+ p[] acts4 ,! ray is b5t on ent]+1 & b5t aga9 on leav+2 b :il/ )9 ! m$ium x cont9ues 9 a /raight l9e4 ,h5ce x is evid5t t by v>i\sly modify+ ! surfaces ( refractive m$ia ! rays ( light may be div]t$ almo/ at pleasure4 ,?is w be r5d]$ cle> by a few simple diagrams4 ,9 ! figures giv5 bel[1 & 9 ! foll[+ page1 ! dott$ l9es repres5t p]p5dicul>s to ! surface at ! po9t :]e ! ray falls1 & x is se5 t ! usual law ( b5d+ t[>ds ! p]p5dicul> on ent]+1 & away f x on leav+ ! d5se m$ium1 is 9 ea* case correctly obs]v$4 ,illu/ration3 ,fig4 #a4 ,illu/ration3 ,fig4 #b4 ,fig4 #b1 t]m$ a prism1 b5ds ! ray p]man5tly to "o side2 fig4 #c1 consi/+ ( two prisms plac$ base to base1 causes rays be=e p>allel to meet 9 a po9t2 & conv]sely1 fig4 #d1 hav+ prisms plac$ edge to edge1 div]ts !m fur!r asund]4 ,illu/ration3 ,fig4 #c4 ,illu/ration3 ,fig4 #d4 ,! v>i\s =ms ( ,l5ses4--,! ph5om5a ( ! refraction ( light are se5 9 ! case ( curv$ surfaces 9 ! same mann] z ) ^? :i* are plane4 ,glasses gr\nd ( a curvil9e> =m are t]m$ ,l5ses4 ,! foll[+ are examples4 ,illu/ration3 ,fig4 #a4 ,illu/ration3 ,fig4 #b4 ,illu/ration3 ,fig4 #c4 ,fig4 #a is a biconvex l5s2 fig4 #b1 a biconcave l5s2 & fig4 #c1 a m5iscus l5s4 ,z f> z reg>ds _! refractive p[]s1 su* figures may be repres5t$1 ne>ly1 by o!rs b\nd by /raight l9es1 & ?us x becomes evid5t t a biconvex l5s t5ds to cond5se rays ( light to a po9t1 & a biconcave to scatt] !m4 ,a m5iscus comb9es bo? actions1 b ! rays are ev5tually b5t toge!r1 ! convex curve ( a m5iscus l5s be+ always great] ?an ! concave4 ,! ,foci ( ,l5ses4--,x has be5 %[n t convex l5ses t5d to cond5se rays ( light & br+ !m toge!r to a po9t4 ,?is po9t is t]m$ ! focus ( ! ,l5s4 ,! foll[+ laws z reg>ds ! focus may be laid d[n3-- ,t rays ( light :i* are pursu+ a p>allel c\rse at ! "t !y ent] ! ,l5s are br\ght to a focus at a po9t ne>] to ! ,l5s ?an div]g+ rays4 ,! rays proce$+ f v di/ant objects are p>allel2 ^? f objects ne> at h& div]ge4 ,! sun's rays are always p>allel1 & ! div]g5ce ( ! o!rs becomes great] z ! di/ance f ! ,l5s is less4 ,! focus ( a ,l5s = p>allel rays is t]m$ ! pr9cipal focus1 & is n subject to v>iation2 ?is is ! po9t ref]r$ to :5 ! focal l5g? ( a ,l5s is spok5 (4 ,:5 ! rays are n p>allel1 b div]ge f a po9t1 t po9t is associat$ ) ! focus1 & ! two are t]m$ conjugate foci4 ,illu/ration ,9 ! above diagram ,a is ! pr9cipal focus1 & ,b & ,c are conjugate foci4 ,any object plac$ at ,b has its focus at ,g1 & conv]sely :5 plac$ at ,c x is 9 focus at ,b4 ,!re=e1 al?\gh ! pr9cipal focus ( a ,l5s 7z det]m9$ by ! degree ( its convexity7 is always ! same1 yet ! focus = objects ne> at h& v>ies1 be+ long] z !y are br\ght clos] to ! ,l5s4 ,=mation ( a ,lum9\s ,image by a ,l5s4--,z ! rays ( light proce$+ f a po9t are br\ght to a focus by means ( a ,l5s1 s are !y :5 !y proce$ f an object1 & 9 t case an image ( ! object is ! result4 ,illu/ration ,! above figure illu/rates ?is4 ,! size ( ! image v>ies ) ! di/ance ( ! arr[ f ! glass--be+ l>g] & =m$ at a po9t fur!r f ! ,l5s z ! object is br\ght ne>]4 ,! refract+ p[] ( ! ,l5s also influ5ces ! result--l5ses ( %ort focal l5g?1 i4 e4 m convex1 giv+ a small] image4 ,9 ord] t ! c\rse pursu$ by p5cils ( rays proce$+ f an object may be easily trac$1 ! l9es f ! b>b ( ! arr[ 9 ! la/ figure are dott$4 ,obs]ve t ! object is necess>ily inv]t$1 & also t ^? rays :i* trav]se ! c5tral po9t ( ! ,l5s1 or ! c5tre ( ! axis1 z x is t]m$1 are n b5t away1 b pursue a c\rse ei!r co9cid5t )1 or p>allel to1 ! orig9al1 z 9 ! case ( refract+ m$ia ) p>allel surfaces4 ,,section ,,iii4 ,! ,photographic ,cam]a4 ,! ,photographic ,cam]a is 9 its ess5tial nature an extremely simple in/rum5t4 ,x consi/s m]ely ( a d>k *amb]1 hav+ an ap]ture 9 front 9 :i* a ,l5s is ins]t$4 ,! accompany+ figure %[s ! simple/ =m ( ,cam]a4 ,illu/ration ,! body is repres5t$ z consi/+ ( two portions :i* slide )9 ea* o!r2 b ! same object ( l5g!n+ or %ort5+ ! focal di/ance may be atta9$ by mak+ ! ,l5s itself movable4 ,a lum9\s image ( any object plac$ 9 front ( ! ,cam]a is =m$ by means ( ! ,l5s1 & receiv$ ^u a surface ( gr\nd glass at ! back "p ( ! in/rum5t4 ,:5 ! ,cam]a is requir$ = use1 ! object is focuss$ ^u ! gr\nd glass1 :i* is !n remov$1 & a slide conta9+ ! s5sitive lay] ins]t$ 9 its place4 ,! lum9\s image1 z =m$ ^u ! gr\nd glass1 is t]m$ ! ,field ( ! ,cam]a2 x is spok5 ( z be+ flat or curv$1 %>p or indi/9ct1 etc4 ,^! & o!r peculi>ities :i* dep5d ^u ! con/ruction ( ! ,l5s w n[ be expla9$4 ,*romatic ,ab]ration ( ,l5ses4--,! outside ( a biconvex l5s is /rictly comp>able ) ! %>p edge ( a prism1 & !re=e necess>ily produces decomposition 9 ! :ite light :i* passes ?r\gh x4 ,! action ( a prism 9 sep>at+ :ite light into its con/itu5t rays may be simply expla9$2--all ! col\r$ rays are refrangible1 b n to ! same ext5t4 ,! indigo & violet are m s ?an ! yell[ & r$1 & consequ5tly !y are sep>at$ f !m1 & occupy a high] position 9 ! ,spectrum4 7,see ! diagram at p4 #dg47 ,a little reflection w %[ t 9 consequ5ce ( ?is unequal refrangibility ( ! col\r$ rays1 :ite light mu/ inv>iably be decompos$ on ent]+ any d5se m$ium4 ,?is is inde$ ! case2 b if ! surfaces ( ! m$ium are p>allel to ea* o!r ! effect is n se51 because ! rays recomb9e on _! em]g5ce1 be+ b5t to ! same ext5t 9 ! opposite direction4 ,h5ce light is transmitt$ col\rless ?r\gh an ord9>y pane ( glass1 b yields ! t9ts ( ! ,spectrum 9 its passage ?r\gh a prism or a l5s1 :]e ! two surfaces are incl9$ to ea* o!r at an acute angle4 ,*romatic ab]ration is correct$ by comb9+ two l5ses cut f v>ieties ( glass :i* diff] 9 _! p[] ( sep>at+ ! col\r$ rays4 ,^! are ! d5se fl9t-glass conta9+ ,oxide ( ,lead1 & ! light cr[n-glass4 ,( ! two l5ses1 ! "o is biconvex1 & ! o!r biconcave2 s t :5 fitt$ toge!r !y produce a comp\nd ,a*romatic l5s ( a m5iscus =m1 ?us3-- ,illu/ration ,! fir/ ,l5s 9 ?is figure is ! fl9t- & ! second ! cr[n-glass4 ,( ! two ! biconvex is ! mo/ p[]ful1 s z to ov]come ! o!r1 & produce a total ( refraction to ! requir$ ext5t4 ,ea* ( ! ,l5ses produces a spectrum ( a diff]5t l5g?2 & ! effect ( pass+ ! rays ?r\gh bo?1 is1 by ov]lapp+ ! col\r$ spaces1 to unite ! complem5t>y t9ts1 & to =m aga9 :ite light4 ,sph]ical ,ab]ration ( ,l5ses4--,! field ( a ,cam]a is n (t5 equally %>p & di/9ct at e "p4 ,if ! c5tre be r5d]$ cle> & well def9$1 ! outside is mi/y2 :il/1 by slightly alt]+ ! position ( ! gr\nd glass1 s z to def9e ! outside portion %>ply1 ! c5tre is ?r[n out ( focus4 ,opticians express ?is by say+ t !re is a want ( prop] flatness ( field2 two causes may be m5tion$ z concurr+ to produce x4 ,! fir/ is sph]ical ab]ration1 by :i* is meant ! prop]ty possess$ by ,l5ses :i* are segm5ts ( sph]es1 ( refract+ rays ( light unequally at diff]5t p>ts ( _! surfaces4 ,! foll[+ diagram %[s ?is3-- ,illu/ration ,obs]ve t ! dott$ l9es :i* fall ^u ! circumf]5ce ( ! ,l5s are br\ght to a focus at a po9t ne>] to ! ,l5s ?an ^? pass+ ?r\gh ! c5tre2 9 o!r words1 ! outside ( ! ,l5s refracts light ! mo/ p[]fully4 ,?is causes a degree ( confusion & indi/9ctness 9 ! image1 f v>i\s rays cross+1 & int]f]+ )1 ea* o!r4 ,sph]ical ab]ration may be avoid$ by increas+ ! convexity ( ! c5tre "p ( ! ,l5s1 s z to add to its refract+ p[] at t p>ticul> po9t4 ,! surface is !n no long] a segm5t ( a sph]e1 b ( an ellipse1 & refracts light m equally4 ,! difficulty ( gr9d+ ,l5ses to an elliptical =m h[ev] is s great1 t ! sph]ical ,l5s is /ill us$1 ! ab]ration be+ correct$ 9 o!r ways4 ,a second cause int]f]+ ) ! di/9ctness ( ! out] portions ( ! image 9 ! ,cam]a is ! obliquity ( "s rays proce$+ f ! object2 9 consequ5ce ( :i* ! image has a curv$ =m1 ) ! concavity inw>ds1 z may be se5 by ref]r+ to ! figure giv5 at page #ec4 ,! foll[+ diagram is meant to expla9 curvature ( ! image4 ,! c5tre l9e runn+ at "r angles to ! g5]al direction ( ! ,l5s is ! axis2 an imag9>y l9e1 on :i* ! ,l5s may be said to rotate z a :eel turns on its axle4 ,! l9es ,a ,a repres5t rays ( light fall+ p>allel to ! axis2 & ! dott$ l9es1 o!rs :i* h an oblique direction2 ,b & ,c %[ ! po9ts at :i* ! two foci are =m$4 ,obs]ve t ^! po9ts1 al?\gh equidi/ant f ! c5tre ( ! ,l5s1 d n fall 9 ! same v]tical plane1 & !re=e !y _c bo? be receiv$ di/9ct ^u ! gr\nd glass ( ! ,cam]a1 :i* w\ld occupy ! position ( ! p]p5dicul> d\ble l9e 9 ! diagram4 ,h5ce x is t ) mo/ l5ses1 :5 ! c5tre ( ! field has be5 focuss$1 ! glass mu/ be %ift$ =w>ds a little to def9e ! outside %>ply4 ,illu/ration ,! ,use ( ,/ops 9 ,l5ses4--,curvature ( ! image & indi/9ctness ( outl9e f sph]ical ab]ration are bo? rem$i$ to a great ext5t by fix+ 9 front ( ! ,l5s a diaphragm hav+ a small c5tral ap]ture4 ,! diagram gives a sectional view ( a ,l5s ) a /op atta*$2 ! exact position x %\ld occupy ) ref]5ce to ! ,l5s is a po9t ( importance1 & influ5ces ! flatness ( ! field4 ,illu/ration ,by us+ a diaphragm ! quantity ( light admitt$ into ! ,cam]a is dim9i%$ 9 proportion to ! size ( ! ap]ture4 ,! image is !re=e less brilliant1 & a long] exposure ( ! s5sitive plate is requir$4 ,9 o!r respects h[ev] ! result is improv$2 ! sph]ical ab]ration is less5$ by cutt+ (f ! outside ( ! ,l5s1 & a portion ( ! oblique rays be+ int]cept$1 ! focus ( ! rema9d] is l5g!n$ out1 & ! image is r5d]$ flatt]1 & improv$ 9 di/9ctness4 ,h5ce also1 :5 a small /op is affix$ to a ,l5s1 a v>iety ( objects1 situat$ at diff]5t di/ances1 are all 9 focus at once2 :]eas1 ) ! full ap]ture ( ! ,l5s1 objects ne> at h& _c be r5d]$ di/9ct ^u ! gr\nd glass at ! same "t ) di/ant objects1 or vice v]s4 ,! ,d\ble or ,portrait ,comb9ation ( ,a*romatic ,l5ses4--,! brightness ( illum9ation ( an image =m$ by a ,l5s is 9 proportion to ! diamet] ( ! ,l5s1 t is1 to ! size ( ! ap]ture by :i* ! ,light is admitt$4 ,! cle>ness or di/9ctness ( outl9e h[ev] is indep5d5t ( ?is1 be+ improv$ by us+ a /op1 :i* less5s ! diamet]4 ,! ,portrait comb9ation ( ,l5ses is con/ruct$ to ensure rapidity ( action by admitt+ a l>ge volume ( light4 ,! foll[+ diagram gives a sectional view4 ,illu/ration ,9 ?is comb9ation ! front ,l5s is an ,a*romatic plano-convex1 )1 ! convex side turn$ t[>d ! object2 & ! second1 :i* takes up ! rays & refracts !m fur!r1 is a comp\nd ,biconvex ,l5s2 !re are !re=e 9 all f\r di/9ct glasses conc]n$ 9 =m+ ! image1 :i* may appe> at fir/ to be an unnecess>ily complex arrangem5t4 ,x is f\nd h[ev] t a good result _c be secur$ by us+ a s+le ,l5s1 :5 a /op is inadmissible4 ,by comb9+ two glasses ( diff]5t curves1 ! ab]rations ( "o correct ^? ( ! o!r to a great ext5t1 & ! field is bo? flatt] & m di/9ct ?an 9 ! case ( an ,a*romatic ,m5iscus employ$ )\t a diaphragm4 ,! manufacture ( ,portrait ,l5ses is a po9t ( great difficulty1 ! glasses requir+ to be gr\nd ) extreme c>e1 9 ord] to avoid di/ortion ( ! image3 h5ce ! mo/ rapid ,portrait ,l5ses1 hav+ l>ge ap]ture & %ort focus1 are (t5 useless unless pur*as$ ( a good mak]4 ,! ,v>iation betwe5 ! ,visual & ,act9ic ,foci 9 ,l5ses4--,! same causes :i* produce *romatic ab]ration 9 a ,l5s1 t5d also to sep>ate ! *emical f ! visual focus4 ,! violet & indigo rays are m /rongly b5t 9 ?an ! yell[1 & /ill m ?an ! r$2 consequ5tly ! focus = ea* ( ^? col\rs is at a diff]5t po9t4 ,! foll[+ diagram %[s ?is4 ,illu/ration ,v repres5ts ! focus ( ! violet ray1 ,y ( ! yell[1 & ,e ( ! r$4 ,h5ce1 z ! *emical action corresponds m to ! violet1 ! mo/ m>k$ act9ic effect w\ld be produc$ at ,v4 ,! lum9\s portion ( ! spectrum h[ev] is ! yell[1 consequ5tly ! visual focus is at ,y4 ,photograph]s h long recogniz$ ?is po9t2 & !re=e1 ) ord9>y ,l5ses1 n correct$ = col\r1 rules are laid d[n z to ! exact di/ance :i* ! s5sitive plate %\ld be %ift$ away f ! visual focus 9 ord] to obta9 ! greate/ am\nt ( di/9ctness ( outl9e 9 ! image impress$ by *emical action4 ,^! rules d n apply to ! ,a*romatic ,l5ses rec5tly describ$4 ,! col\r$ rays be+ 9 t case b5t toge!r aga9 & reunit$1 ! two foci also ne>ly correspond4 ,by a little fur!r correction to a po9t high] 9 ! ,spectrum1 !y are made to d s p]fectly4 ,,section ,,iv4 ,on ! ,photographic ,action ( ,col\r$ ,light4 ,x has already be5 m5tion$ 9 ! ,fir/ ,section ( ?is ,*apt] t c]ta9 ( ! elem5t>y col\rs ( :ite light1 viz4 ! violet & indigo1 are peculi>ly active 9 decompos+ ! ,photographic ,salts ( ,silv]2 b !re are "s po9ts ( importance relat+ to ! same subject :i* require a fur!r notice4 ,! t]m act9ism 7,gr4 1 a ray or fla%7 has be5 propos$ z conv5i5t to designate ! prop]ty possess$ by light ( produc+ *emical *ange2 ! rays to :i* ! effect is especially due be+ kn[n z act9ic rays4 ,if ! pure ,sol> ,spectrum =m$ by prismatic analysis 9 ! mann] repres5t$ at page #dg be all[$ to imp+e ^u a prep>$ s5sitive surface ( ,iodide ( ,silv]1 ! lat5t image be+ subsequ5tly develop$ by a r$uc+ ag5t1 ! effect produc$ w be some?+ simil> to t repres5t$ 9 ! foll[+ diagram3-- ,illu/ration3 ,fig4 #a4 ,illu/ration3 ,fig4 #b4 ,fig4 #a %[s ! visible spectrum z x appe>s to ! eye2 ! brighte/ "p be+ 9 ! yell[ space1 & ! light gradually %ad+ (f until x ceases to be se54 ,fig4 #b repres5ts ! *emical effect produc$ by ?r[+ ! ,spectrum ^u ,iodide ( ,silv]4 ,obs]ve t ! d>k5+ *>act]i/ic ( *emical action is mo/ evid5t 9 ! upp] spaces1 :]e ! light is feeble1 & is altoge!r abs5t at ! po9t correspond+ to ! bright yell[ spot ( ! visible spectrum4 ,! act9ic & lum9\s spectra are !re=e totally di/9ct f ea* o!r1 & ! ^w ,photography1 :i* signifies ! process ( tak+ pictures by light1 is 9 reality inaccurate4 ,to ^? :o h n ! opportunity ( work+ ) ! ,sol> ,spectrum1 ! foll[+ exp]im5ts w be useful 9 illu/rat+ ! ,photographic value ( col\r$ light4 ,exp]im5t ,i4--,take a %eet ( s5sitive pap] prep>$ ) ,*loride ( ,silv]1 & lay ^u x /rips ( blue1 yell[1 & r$ glass4 ,on exposure to ! sun's rays = a few m9utes1 ! "p b5ea? ! blue glass d>k5s rapidly1 :il/ t cov]$ by ! r$ & yell[ glass is p]fectly protect$4 ,?is result is ! m /rik+ f ! extreme transp>5cy ( ! yell[ glass1 giv+ ! idea t ! ,*loride w\ld c]ta9ly be black5$ fir/ at t po9t4 ,on ! o!r h&1 ! blue glass appe>s v d>k1 & effectually conceals ! tissue ( ! pap] f view4 ,exp]im5t ,,ii4--,select a vase ( fl[]s ( diff]5t %ades ( sc>let1 blue1 & yell[1 & make a ,photographic copy ( !m1 by developm5t1 ^u ,iodide ( ,silv]4 ,! blue t9ts w be f\nd to act mo/ viol5tly ^u ! s5sitive comp\nd1 :il/ ! r$s & yell[s are sc>cely visible2 7 x n t x is difficult to procure 9 nature pure & homog5e\s t9ts1 free f admixture ) o!r col\rs1 !y w\ld make no impression :atev] ^u ! plate4 ,9 exemplify+ fur!r ! importance ( di/+ui%+ betwe5 visual & act9ic rays ( light1 we may obs]ve t if ! two 7 9 all respects ! same4 ,photography mu/ cease to exi/ z an ,art4 ,x w\ld be impossible to make use ( ! m s5sitive *emical prep>ations f ! difficulties :i* w\ld att5d ! previ\s prep>ation & subsequ5t developm5t ( ! plates4 ,^! op]ations are n[ conduct$ 9 :at is t]m$ a d>k room2 b x is d>k only 9 a ,photographic s5se1 be+ illum9at$ by means ( yell[ light1 :i*1 :il/ x enables ! op]ator easily to wat* ! progress ( ! "w1 produces no injuri\s effect ^u ! s5sitive surfaces4 ,if ! w9d[s ( ! room 7 glaz$ ) blue 9 place ( yell[ glass1 !n x w\ld be /rictly a d>k room1 b "o altoge!r unfitt$ = ! purpose int5d$4 ,ano!r po9t connect$ ) ! same subject & wor?y ( note is--! ext5t to :i* ! s5sibility ( ! ,photographic comp\nds is influ5c$ by atmosph]ic conditions n visibly int]f]+ ) ! brightness ( ! light4 ,x is natural to suppose t ^? days on :i* ! sun's rays are ! mo/ p[]ful w\ld be ! be/ = rapid impression1 b su* is n by any means ! case4 ,if ! light is at all ( a yell[ ca/1 h[ev] bright x may be1 its act9ic p[] w be small4 ,x w also be (t5 obs]v$ 9 work+ t[>ds ! ev5+1 t a sudd5 dim9ution ( s5sibility 9 ! plates beg9s to be p]ceptible at a "t :5 b little diff]5ce c be detect$ 9 ! brilliancy ( ! light2 ! sett+ sun has sunk beh9d a gold5 cl\d1 & all *emical action is soon at an end4 ,9 ! same mann] is expla9$ ! difficulty ( obta9+ ,photographs 9 ! gl[+ light ( tropical climates2 ! sup]iority ,( ! e>ly mon?s ( spr+ ov] ^? ( ! midsumm]2 ( ! morn+ sun to t ( ! aft]noon1 etc4 ,april & ,may are usually consid]$ ! be/ mon?s = rapid impression 9 ?is c\ntry2 b ! light cont9ues good until ! end ( ,july4 ,9 ,augu/ & ,septemb] a long] exposure ( ! plates w be requir$4 ,,! ,,sup]ior ,,s5sibility ,,( ,,bromide ,,( ,,silv] ,,to ,,col\r$ ,,light4 ,9 copy+ ! ,sol> ,spectrum alt]nately ^u a surface ( ,iodide & ,bromide ( ,silv]1 we notice a diff]5ce 9 ! ,photographic prop]ties ( ^! two salts4 ,! latt] is affect$ m ext5sively1 to a po9t l[] 9 ! spectrum1 ?an ! =m]4 ,9 ! case ( ! ,iodide ( ,silv]1 ! action ceases 9 ! ,blue space2 b ) ! ,bromide x rea*es to ! ,gre54 ,?is is %[n 9 ! foll[+ diagrams1 :i* are drawn f ! obs]vations ( ,mr4 ,crookes 7',photographic ,j\rnal1' vol4 i4 p4 #ajj73-- ,illu/ration3 ,fig4 #a4 ,fig4 #b4 ,fig4 #c4 ,fig4 #a repres5ts ! *emical spectrum on ,bromide ( ,silv]2 fig4 #b1 ! same ^u ,iodide ( ,silv]2 & fig4 #c1 ! visible spectrum4 ,x might p]haps be suppos$ t ! sup]ior s5sibility ( ! ,bromide ( ,silv] to gre5 rays ( light w\ld r5d] t salt useful to ! ,photograph] 9 copy+ l&scape sc5]y2 & inde$ x is ! op9ion ( _m t1 9 ! ,calotype pap] process1 ! d>k col\r ( foliage is bett] r5d]$ by a mixture ( ,bromide & ,iodide ( ,silv] ?an by ! latt] salt alone4 ,?is h[ev] _c dep5d ^u ! great] s5sibility ( ! ,bromide to col\r$ light1 z may easily be prov$4-- ,! diagrams giv5 above are %ad$ to repres5t ne>ly1 ! relative int5sity ( ! *emical action ex]t$ by ! rays at diff]5t po9ts ( ! spectrum2 & on ref]r+ to !m x w be se5 t ! maximum po9t ( blackness is 9 ! indigo & violet space1 ! action be+ m feeble 9 ! blue space l[] d[n2 !re are also highly refrangible rays ext5d+ upw>ds f> beyond ! visible col\rs1 & ^! invisible rays are actively conc]n$ 9 ! =mation ( ! image4 ,x is evid5t !re=e t ! am\nt ( effect produc$ by a pure gre51 or ev5 a light blue t9t1 ^u a surface ( ,bromide ( ,silv] is v small z comp>$ ) t ( an indigo or violet2 & h5ce1 z 9 copy+ natural objects radiations ( all k9ds are pres5t at ! same "t1 ! gre5 t9ts h n "t to act be=e ! image is impress$ by ! m refrangible rays4 ,sir ,john ,h]s*el propos$ to r5d] col\r$ light m available 9 ,photography by sep>at+ ! act9ic rays ( high refrangibility1 & work+ only ) ^? :i* correspond to ! blue & gre5 spaces 9 ! spectrum4 ,?is may be done by plac+ 9 front ( ! ,cam]a a v]tical glass tr\gh conta9+ a solution ( ,sulphate ( ,qu99e4 ,pr(essor ,/okes has %[n t ?is liquid possesses curi\s prop]ties4 ,9 transmitt+ rays ( light x modifies !m s t !y em]ge ( l[] refrangibility1 & incapable ( produc+ ! same act9ic effect4 ,sulphate ( ,qu99e is1 if we may use ! t]m1 opaque to all act9ic rays high] ?an ! blue-col\r$ space4 ,! proposition ( ,sir ,john ,h]s*el above ref]r$ to 0 !re=e to employ a ba? ( ,sulphate ( ,qu99e1 & hav+ elim9at$ ! act9ic rays ( high refrangibility1 to "w ^u ,bromide ( ,silv] ) ^? correspond+ to ! l[]-col\r$ spaces4 ,9 ?is way he conceiv$ t a m natural effect might be obta9$4 ,if ,photographic comp\nds %\ld be discov]$ ( great] s5sibility ?an any we at pres5t possess1 ! use ( ! ,qu99e ba? w p]haps be adopt$2 b at pres5t we tru/ to ! sup]ior int5sity ( ! invisible rays = ! =mation ( ! image1 & h5ce ! employm5t ( ,bromide ( ,silv] is less /rongly indicat$4 ,^! rem>ks apply to ,photographs tak5 by sunlight4 ,mr4 ,crookes /ates t 9 work+ ) artificial light1 su* z gas or camph9e1 ! case is diff]5t4 ,act9ic rays ( high refrangibility are comp>atively want+ 9 gas-light1 ! great bulk ( ! ,photographic rays be+s f\nd to lie )9 ! limits ( ! visible spectrum1 & consequ5tly act+ m en]getically ^u ,bromide ?an on ,iodide ( ,silv]4 ,explanation ( ! mode 9 :i* ,col\r$ ,objects impress ! ,s5sitive ,film4--,! fact ( :i* we h be5 speak+1 viz4 t ! natural col\rs are n always correctly repres5t$ 9 photography1 is (t5 urg$ 9 depreciation ( ! art1--:5 lights1 are repres5t$ by %ad[s1 x is said1 h[ c a tru?ful picture be expect$8 ,! ins5sitiv5ess ( ,iodide ( ,silv] to ! col\rs occupy+ ! l[] portion ( ! spectrum w\ld inde$ pres5t an insup]able difficulty if ! t9ts ( ,nature 7 pure & homog5e\s3 su* h[ev] is n ! case4 ,ev5 ! mo/ sombre col\rs are accompani$ by scatt]$ rays ( :ite light 9 quantity amply suffici5t to affect ! s5sitive film4 ,?is is especially se5 :5 ! col\r$ body possesses a good reflect+ surface2 & h5ce "s v>ieties ( foliage1 z = in/ance ! ,ivy1 ) its smoo? & poli%$ leaf1 are m easily photograph$ ?an o!rs4 ,s aga9 ) reg>d to drap]y 9 ! dep>tm5t ( portraiture--x is necess>y to att5d n only to ! col\r1 b also to ! mat]ial ( :i* x is compos$4 ,silks & sat9s are fav\rable1 z reflect+ mu* light1 :il/ velvets & co>se /uffs ( all k9ds1 if at all d>k1 produce v little effect ^u ! s5sitive film4 ,,section ,v4 ,on ,b9ocul> ,vision & ! ,/]eoscope4 ,an object is said to be /]eoscopic 7 solid1 & 1 ,i see7 :5 x /&s out 9 relief1 & gives to ! eye ! impression ( solidity4 ,?is subject 0 fir/ expla9$ by ,pr(essor ,:eat/one 9 a memoir on b9ocul> vision1 publi%$ 9 ! ',philosophical ,transactions' = #ahch2 9 :i* he %[s t solid bodies project diff]5t p]spective figures ^u ea* ret9a1 & t ! illusion ( solidity may be artificially produc$ by means ( ! ,/]eoscope4 ,! ph5om5a ( b9ocul> vision may be simply sket*$ z foll[s3--,if a cube1 or a small box ( an oblong =m1 be plac$ at a %ort di/ance 9 front ( ! obs]v]1 & view$ att5tively ) ! "r & left eye sep>ately & 9 succession1 x w be f\nd t ! figure p]ceiv$ 9 ! two cases is diff]5t2 t ea* eye sees m ( "o side ( ! box1 & less ( ! o!r2 & t 9 nei!r in/ance is ! effect exactly ! same z t giv5 by ! two eyes employ$ conjo9tly4 ,a silv] p5cil-case1 or a p5-hold]1 may be us$ to illu/rate ! same fact4 ,x %\ld be held at ab\t six or eight in*es di/ant f ! root ( ! nose1 & q at "r angles to ! face1 s t ! l5g? ( ! p5cil is conceal$ by ! po9t4 ,!n1 :il/ x rema9s fix$ 9 ?is position1 ! left & "r eye are to be alt]nately clos$3 9 ea* case a portion ( ! opposite side ( ! p5cil w be r5d]$ visible4 ,illu/ration3 ,fig4 #a4 ,fig4 #b4 ,! prec$+ diagrams exhibit ! appe>ance ( a bu/ z se5 by ea* eye successively4 ,obs]ve t ! second figure1 :i* repres5ts ! impression receiv$ by ! "r eye1 is m ( a full face ?an fig4 #a1 :i*1 be+ view$ f a po9t remov$ a little to ! left1 p>takes ( ! "* ( a pr(ile4 ,! human eyes are plac$ ab\t #b-a_/b in*es1 or f t to #b-e_/h in*es1 asund]2 h5ce x foll[s t1 ! po9ts ( sight be+ sep>at$1 a dissimil> image ( a solid object is =m$ by ea* eye4 ,we d n h[ev] see two images1 b a s+le "o1 :i* is /]eoscopic4 ,9 look+ at a picture pa9t$ on a flat surface ! case is diff]5t3 ! eyes1 z be=e1 =m two images1 b ^! images are 9 e respect simil>2 consequ5tly ! impression ( solidity is want+4 ,a s+le picture1 !re=e1 _c be made to appe> /]eoscopic4 ,to convey ! illusion two pictures mu/ be employ$1 ! "o be+ a "r & ! o!r a left p]spective projection ( ! object4 ,! pictures mu/ also be s arrang$1 t ea* is pres5t$ to its own eye1 & t ! two appe> to proce$ f ! same spot4 ,! reflect+ /]eoscope1 employ$ to effect ?is1 =ms lum9\s images ( ! b9ocul> pictures1 & ?r[s ^! images toge!r1 s t1 on look+ into ! in/rum5t1 only a s+le image is se51 9 a c5tral position4 ,x %\ld1 h[ev]1 be und]/ood1 t no optical arrangem5t ( any k9d is indisp5sably requir$1 s9ce x is q possible1 ) a little ef=t1 to comb9e ! two images by ! unaid$ organs ( vision4 ,! foll[+ diagram w make ?is obvi\s3-- ,illu/ration ,! circles ,a & ,b repres5t two waf]s1 :i* are /uck on pap] at a di/ance ( ab\t ?ree in*es f ea* o!r4 ,!y are !n view$ by squ9t+ /rongly1 or turn+ ! eyes inw>ds t[>ds ! nose1 until ! "r eye looks at ! left waf]1 & ! left eye at ! "r waf]4 ,ea* waf] w !n appe> to become d\ble1 f\r images be+ se51 ! two c5tral ( :i* w gradually approa* ea* o!r until !y coalesce4 ,/]eoscopic pictures1 prop]ly arrang$1 may be exam9$ 9 ! same mann]2 & x w be f\nd t ! resultant solid image is =m$ midway1 at a po9t :]e two l9es1 drawn across f ! eyes to ! pictures1 cut "o ano!r4 ,! exp]im5t "h m5tion$ is sometimes a pa9ful "o1 & _c easily be made if ! eyes are n ( equal /r5g?2 b x w s]ve to %[ t ! ess5tial pr9ciple resides 9 ! b9ocul> repres5tation ( ! object1 & n 9 ! in/rum5t employ$ to view x4 ,9 ,mr4 ,:eat/one's reflect+ ,/]eoscope mirrors are us$4 ,! pr9ciple ( ! in/rum5t is z foll[s3-- objects plac$ 9 front ( a mirror h _! reflect$ images app>5tly beh9d ! mirror4 ,by arrang+ two mirrors at a c]ta9 incl9ation to ea* o!r1 ! images ( ! d\ble picture may be made to approa* until !y coalesce1 & ! eye p]ceives a s+le "o only4 ,! foll[+ diagram w expla9 ?is4 ,illu/ration ,! rays proce$+ f ! /> on ei!r side pass 9 ! direction ( ! arr[s1 be+ ?r[n (f f ! mirror 7repres5t$ by ! ?ick black l9e7 & ent]+ ! eyes at ,r & ,l4 ,! reflect$ images appe> beh9d ! mirror1 unit+ at ! po9t ,a4 ,! reflect+ ,/]eoscope is adapt$ pr9cipally = view+ l>ge pictures4 ,x is a v p]fect in/rum5t1 & admits ( a v>iety ( adju/m5ts1 by :i* ! app>5t size & di/ance ( ! ,/]eoscopic image may be v>i$ almo/ at pleasure4 ,! l5ticul> ,/]eoscope ( ,sir ,david ,brew/] is a m portable =m ( app>atus4 ,a sectional view is giv5 9 ! diagram4 ,illu/ration ,! brass tubes to :i* ! eyes ( ! obs]v] are appli$ conta9 ea* a semi-l5s1 =m$ by divid+ a common l5s ?r\gh ! c5tre & cutt+ ea* half into a circul> =m 7fig4 #a 9 ! foll[+ page74 ,! half-l5s view$ 9 section 7fig4 #b7 is !re=e ( a prismatic %ape1 & :5 plac$ ) its %>p edge z 9 ! diagram above1 alt]s ! direction ( ! rays ( light proce$+ f ! picture1 b5d+ !m outw>ds or away f ! c5tre1 s t 9 accordance ) well-kn[n optical laws !y appe> to come 9 ! direction ( ! dott$ l9es 9 ! diagram 79 ! la/ page71 & ! two images coalesce at _! po9t ( junction4 ,9 ! in/rum5t z x is (t5 sold1 "o ( ! l5ses is made movable1 & by turn+ x r\nd ) ! f+] & ?umb x w be se5 t ! positions ( ! images may be %ift$ at pleasure4 ,fig4 #a4 ,illu/ration ,fig4 #b4 ,rules = tak+ ,b9ocul> ,photographs4--,9 view+ v di/ant objects ) ! eyes1 ! images =m$ on ! ret9 are n suffici5tly dissimil> to produce a v ,/]eoscopic effect2 h5ce x is (t5 requir$1 9 tak+ b9ocul> pictures1 to sep>ate ! ,cam]as m widely ?an ! two eyes are sep>at$1 9 ord] to give a suffici5t appe>ance ( relief4 ,mr4 ,:eat/one's orig9al directions 71 to all[ ab\t "o foot ( sep>ation = ea* tw5ty-five feet ( di/ance1 b consid]able latitude may be p]mitt$4 ,if ! ,cam]as be n plac$ f> en\gh ap>t1 ! dim5sions ( ! /]eoscopic image f be=e backw>ds w be too small1--/atues look+ l bas-reliefs1 & ! circul> trunks ( trees appe>+ oval1 ) ! long diamet] transv]se4 ,on ! o!r h&1 :5 ! sep>ation is too wide1 ! rev]se obta9s1--objects = in/ance :i* are squ>e1 assum+ an oblong %ape po9t+ t[>ds ! obs]v]4 ,to und]/& ! cause ( ?is1 ! foll[+ law 9 optics %\ld be /udi$3--,! di/ance ( objects is e/imat$ by ! ext5t to :i* ! axes ( ! eyes mu/ be conv]g$ to view !m4 ,if we h to turn our eyes /rongly inw>ds1 we judge ! object to be ne>2 b if ! eyes rema9 ne>ly p>allel1 we suppose x to be di/ant4 ,illu/ration ,! above figures repres5t six-sid$ truncat$ pyramids1 ea* ) its apex t[>ds ! obs]v]1 ! c5tres ( ! two small] int]ior hexagons be+ m widely sep>at$ ?an ^? ( ! l>g] ext]ior ones4 ,by conv]g+ ! eyes ^u !m s z to unite ! c5tral images 9 ! mann] repres5t$ 9 page #fh a great] am\nt ( conv]g5ce w be requir$ to br+ toge!r ! two summits ?an ! bases1 & h5ce ! summits w appe> ! ne>e/ to ! eye2 t is to say1 ! resultant c5tral figure w acquire ! additional dim5sion ( height1 & appe> z a solid cone1 /&+ p]p5dicul>ly ^u its base3 fur!r1 ! m widely ! summits are sep>at$ 9 relation to ! bases1 ! tall] w ! cone be1 al?\gh a great] ef=t w be requir$ to coalesce ! figures4 ,b9ocul> ,photographs tak5 ) too mu* sep>ation ( ! ,cam]as1 are di/ort$ f a simil> cause1--s /rong a conv]g5ce be+ requir$ to unite !m t c]ta9 p>ts ( ! picture appe> to approa* ne> to ! eye2 & ! dep? ( ! solid image is increas$4 ,?is effect is mo/ obs]vable :5 ! picture embraces a v>iety ( objects1 situat$ 9 diff]5t planes4 ,9 ! case ( views :i* are q di/ant1 no ne> objects be+ admitt$1 ! ,cam]as may be plac$ ) especial ref]5ce to !m1 ev5 z f> z twelve feet ap>t1 )\t produc+ di/ortion4 ,x is sometimes obs]vable1 9 look+ at ,/]eoscopic pictures1 t !y convey an errone\s impression ( ! real size & di/ance ( ! object4 ,= in/ance1 9 us+ ! l>ge reflect+ ,/]eoscope1 if1 :5 ! adju/m5ts h be5 made & ! images prop]ly unit$1 ! two pictures be mov$ sl[ly =w>d1 ! eyes rema9+ fix$ ^u ! mirrors1 ! ,/]eoscopic image w gradually *ange its "*1 ! v>i\s objects x embraces appe>+ to become dim9i%$ 9 size1 & approa*+ ne> to ! obs]v]3 :il/ if ! pictures be pu%$ backw>ds1 ! image w enl>ge & rec$e to a di/ance4 ,s1 aga91 if an ord9>y slide = ! l5ticul> ,/]eoscope be divid$ 9 ! c5tre1 &1 look+ into ! in/rum5t until ! images coalesce1 ! two halves be sl[ly sep>at$ f ea* o!r1 ! solid picture w seem to become l>g] & to rec$e f ! eye4 ,x is easy to und]/& ! cause ( ?is4 ,:5 ! pictures 9 ! reflect+ ,/]eoscope are mov$ =w>ds1 ! conv]g5ce ( ! optic axes is increas$3 ! image !re=e appe>s ne>]1 9 accordance ) ! la/-m5tion$ law4 ,b to convey ! impression ( ne>ness is equival5t to an app>5t dim9ution 9 size1 = we judge ( ! dim5sions ( a body v mu* 9 relation to its suppos$ di/ance4 ,( two figures1 = in/ance1 appe>+ ( ! same height1 "o kn[n to be a hundr$ y>ds (f might be consid]$ colossal1 :il/ ! o!r1 obvi\sly ne> at h&1 w\ld be view$ z a /atuette4 ,^! facts1 ) o!rs n m5tion$1 are ( great int]e/ & importance1 b _! fur!r consid]ation does n fall )9 ! b\nds orig9ally prescrib$ to u4 ,! practical details ( ,/]eoscopic ,photography h be5 arrang$ 9 a di/9ct ,section1 & w be f\nd includ$ 9 ! ,second ,"p ( ! ,"w4#aa #aa ,= a m full & detail$ explanation ( ! ,/]eoscopic ph5om5a1 see an ab/ract ( ,pr(essor ,tyndall's lectures 9 ! ?ird volume ( ! ',photographic ,j\rnal4' ,,*apt] ,,vi4 ,,! ,,photographic ,,prop]ties ,,( ,,iodide ,,( ,,silv] ,,^u ,,collodion4 ,9 ! prec$+ "p ( ?is ,"w ! physical & *emical prop]ties ( ,*loride & ,iodide ( ,silv] h be5 describ$1 ) ! *anges :i* !y exp]i5ce by ! action ( ,light4 ,no?+ h[ev] has be5 said ( ! surface us$ to support ! ,iodide ( ,silv]1 & to expose x 9 a f9ely divid$ /ate to ! influ5ce ( ! act9ic radiations4 ,?is omission w n[ be suppli$1 & ! use ( ,collodion w engage our att5tion4 ,! s5sibility ( ,iodide ( ,silv] ^u ,collodion is greatly sup]ior to t ( ! same salt employ$ 9 conjunction ) any o!r vehicle at pres5t kn[n4 ,h5ce ! ,collodio-,iodide film w sup]s$e ! pap] & ,album5 processes 9 all cases :]e objects liable to move are to be copi$4 ,! causes ( ?is sup]ior s5sitiv5ess1 z f> z asc]ta9$1 may be ref]r$ to ! /ate ( loose coagulation ( a ,collodion film & o!r p>ticul>s pres5tly to be notic$4 ,x mu/ h[ev] be all[$ t !re are yet "s po9ts affect+ ! s5sitiv5ess ( ,iodide ( ,silv]1 bo? me*anical & *emical1 ( ! exact nature ( :i* we are ignorant4 ,! pres5t ,*apt] may be divid$ into f\r ,sections3--! nature ( ,collodion2 ! *emi/ry ( ! ,nitrate ,ba?2 ! causes affect+ ! =mation & developm5t ( ! ,image ^u ,collodion2 ! v>i\s irregul>ities 9 ! developm5t ( ! ,image4 ,,section ,i4 ,collodion4 ,collodion 7s nam$ f ! ,greek ^w 1 to /ick7 is a glut9\s1 transp>5t fluid1 procur$1 z g5]ally said1 by dissolv+ ,gun-,cotton 9 ,e!r4 ,x 0 orig9ally us$ = surgical purposes only1 be+ sme>$ ov] w\nds & raw surfaces1 to pres]ve !m f contact ) ! air by ! t\gh film :i* x leaves on evaporation4 ,photograph]s employ x to support a delicate film ( ,iodide ( ,silv] ^u ! surface ( a smoo? glass plate4 ,two elem5ts ent] into ! composition ( ,collodion3 fir/1 ! ,gun-,cotton2 second1 ! fluids us$ to dissolve x4 ,ea* ( ^! w be treat$ 9 succession4 ,,*emi/ry ,,( ,,pyroxyl9e4 ,gun-,cotton or ,pyroxyl9e is ,cotton or ,pap] :i* has be5 alt]$ 9 composition & prop]ties by treatm5t ) /rong acids4 ,bo? ,cotton & ,pap] are1 *emically1 ! same4 ,!y consi/ ( fibres :i* are f\nd on analysis to h a con/ant composition1 conta9+ ?ree elem5t>y bodies1 ,c>bon1 ,hydrog51 & ,oxyg51 unit$ toge!r 9 fix$ proportions4 ,to ?is comb9ation ! t]m ,lign9e or ,cellulose#ab has be5 appli$4 #ab ,lign9e & ,cellulose are n precisely id5tical sub/ances4 ,! latt] is ! mat]ial compos+ ! cell-wall2 ! =m]1 ! conta9$ matt] 9 ! cell4 ,cellulose is a def9ite *emical comp\nd1 9 ! same s5se z ,/>* or ,sug>1 & consequ5tly1 :5 treat$ ) v>i\s reag5ts1 x exhibits prop]ties peculi> to itself4 ,x is insoluble 9 mo/ liquids1 su* z ,wat]1 ,alcohol1 ,e!r1 etc41 & also 9 dilute acids2 b :5 act$ ^u by ,nitric ,acid ( a c]ta9 /r5g? x liquefies & dissolves4 ,x has be5 already %[n 7p4 #ab7 t :5 a body dissolves 9 ,nitric ,acid ! solution is n usually ( ! same nature z an aque\s solution2 & s 9 ?is case--! ,nitric ,acid imp>ts ,oxyg5 fir/ to ! ,cotton1 & aft]w>ds dissolves x4 ,prep>ation ( ,pyroxyl9e4--,if1 in/ead ( treat+ ,cotton ) ,nitric ,acid1 a mixture ( ,nitric & ,sulphuric ,acids 9 c]ta9 proportions be us$1 ! effect is peculi>4 ,! fibres contract slightly1 b und]go no o!r visible alt]ation4 ,h5ce we are at fir/ dispos$ to ?9k ! mix$ ,acids ineffectual4 ,?is idea h[ev] is n correct1 s9ce on mak+ ! exp]im5t ! prop]ties ( ! cotton are f\nd to be *ang$4 ,its weight has increas$ by m ?an "o-half2 x has become soluble 9 v>i\s liquids1 su* z ,acetic ,e!r1 ,e!r & ,alcohol1 etc41 &1 :at is m rem>kable1 x no long] burns 9 ! air quietly1 b explodes on ! application ( flame ) great] or less viol5ce4 ,?is *ange ( prop]ties cle>ly %[s1 t al?\gh ! fibr\s /ructure ( ! mat]ial is unaffect$1 x is no long] ! same sub/ance1 & consequ5tly *emi/s h assign$ x a diff]5t "n1 viz4 ,pyroxyl9e4 ,to produce ! peculi> *ange by :i* ,cotton is conv]t$ into ,pyroxyl9e1 bo? ,nitric & ,sulphuric ,acids are1 z a rule1 requir$2 b ( ! two ! =m] is ! mo/ important4 ,on analyz+ ,pyroxyl9e1 ,nitric ,acid1 or a body analog\s to x1 is detect$ 9 consid]able quantity1 b n ,sulphuric ,acid4 ,! latt] ,acid1 9 fact1 s]ves b a tempor>y purpose1 viz4 to prev5t ! ,nitric ,acid f dissolv+ ! pyroxyl9e1 :i* x w\ld be liable to d if employ$ alone4 ,! ,sulphuric ,acid prev5ts ! solution by remov+ wat] f ! ,nitric ,acid1 & s produc+ a high] degree ( conc5tration2 ,pyroxyl9e1 al?\gh soluble 9 a dilute1 is n s 9 ! /rong ,acid1 & h5ce x is pres]v$4 ,! prop]ty possess$ by ,oil ( ,vitriol ( remov+ wat] f o!r bodies1 is "o ) :i* x is well to be acqua9t$4 ,a simple exp]im5t w s]ve to illu/rate x4 ,let a small vessel ( any k9d be fill$ to ab\t two-?irds ) ,oil ( ,vitriol1 & set aside = a few days2 at ! end ( t "t1 & especially if ! atmosph]e be damp1 x w h absorb$ suffici5t moi/ure to cause x to fl[ ov] ! edge4 ,n[ ev5 ! /ronge/ reag5ts employ$ 9 *emi/ry conta91 almo/ inv>iably1 wat] 9 great] or less] quantity4 ,pure ,anhydr\s ,nitric ,acid is a :ite1 solid sub/ance2 ,hydro*loric ,acid is a gas3 & ! liquids sold "u ^? names are m]ely solutions4 ,! effect !n ( mix+ /rong ,oil ( ,vitriol ) aque\s ,nitric ,acid is to remove wat] 9 proportion to ! am\nt us$1 & to produce a liquid conta9+ ,nitric ,acid 9 a high /ate ( conc5tration1 & ,sulphuric ,acid m or less dilut$4 ,?is liquid is ! ,nitro-,sulphuric ,acid employ$ 9 ! prep>ation ( ,pyroxyl9e4 ,v>i\s =ms ( ,pyroxyl9e4--,v soon aft] ! fir/ ann\ncem5t ( ! discov]y ( ,pyroxyl9e1 mo/ animat$ discussions arose among/ *emi/s ) reg>d to its solubility & g5]al prop]ties4 ,"s spoke ( a solution ( ,gun-,cotton 9 ,e!r2 :il/ o!rs d5i$ its solubility 9 t m5/ruum2 a ?ird class1 by foll[+ ! process describ$1 obta9$ a sub/ance :i* 0 n explosive1 & !re=e c\ld sc>cely be t]m$ ,gun-,cotton4 ,on fur!r inve/igations "s ( ^! anomalies 7 cle>$ up1 & x 0 f\nd t !re 7 v>ieties ( ,pyroxyl9e1 dep5d+ ma9ly ^u ! degree ( /r5g? ( ! ,nitro-,sulphuric ,acid employ$ 9 ! prep>ation4 ,/ill ! subject 0 obscure until ! publication ( rese>*es by ,mr4 ,e4 ,a4 ,had[4 ,^! inve/igations1 conduct$ 9 ! ,laboratory ( ,k+'s ,college1 ,london1 7 publi%$ 9 ! ,j\rnal ( ! ,*emical ,society4 ,con/ant ref]5ce w be made to !m 9 ! foll[+ rem>ks4 ,we notice--fir/1 ! *emical con/itution ( ,pyroxyl9e2 secondly1 its v>ieties2 & ?irdly1 ! means adopt$ to procure a ,nitro-,sulphuric ,acid ( ! prop] /r5g?4 a4 ,con/itution ( ,pyroxyl9e4--,pyroxyl9e has be5 sometimes spok5 ( z a ,salt ( ,nitric ,acid1 a ,nitrate ( ,lign9e4 ,?is view h[ev] is errone\s1 s9ce x c be %[n t ! sub/ance pres5t is n ,nitric ,acid1 al?\gh analog\s to x4 ,x is ! ,p]oxide ( ,nitrog51 :i* is int]m$iate 9 composition betwe5 ,nitr\s ,acid 7,,no#c7 & ,nitric ,acid 7,,no#e74 ,p]oxide ( ,nitrog5 7,,no#d7 is a gase\s body ( a d>k r$ col\r2 x possesses no acid prop]ties1 & is incapable ( =m+ a class ( salts4 ,9 ord] to und]/& 9 :at /ate ?is body is comb9$ ) cotton fibre to =m ,pyroxyl9e1 x w be necess>y to digress = a %ort "t4 ,law ( ,sub/itution4--,by ! c>eful /udy ( ! action ( ,*lor9e1 & ( ,nitric ,acid1 ^u v>i\s organic sub/ances1 a rem>kable s]ies ( comp\nds has be5 discov]$1 conta9+ a portion ( ,*lor9e or ( ,p]oxide ( ,nitrog5 9 ! place ( ,hydrog54 ,! peculi>ity ( ^! sub/ances is1 t !y /rongly resemble ! orig9als 9 _! physical1 & (t5 9 _! *emical prop]ties4 ,x might h be5 suppos$ t ag5ts ( su* active *emical aff9ities z ,*lor9e & ,oxide ( ,nitrog5 w\ld1 by _! m]e pres5ce 9 a body1 produce a m>k$ effect2 yet x is n s 9 ! case be=e u4 ,! primitive type or con/itution ( ! sub/ance modifi$ rema9s ! same1 ev5 ! cry/all9e =m be+ (t5 unaffect$4 ,x seems z if ! body by :i* ! ,hydrog5 _h be5 displac$ _h /epp$ 9 quietly & tak5 up its position 9 ! framework ( ! :ole )\t di/urbance4 ,_m comp\nds ( ?is k9d are kn[n2 !y are t]m$ by *emi/s sub/itution comp\nds4 ,! law inv>iably obs]v$ is1 t ! sub/itution takes place 9 equal atoms3 a s+le atom ( ,*lor9e1 = in/ance1 displaces "o ( ,hydrog52 two ( ,*lor9e displace two ( ,hydrog51 & s on1 until1 9 "s cases1 ! :ole ( ! latt] elem5t is sep>at$4 ,9 illu/ration ( ^! rem>ks1 take ! foll[+ in/ances3--,acetic ,acid conta9s ,c>bon1 ,hydrog51 & ,oxyg52 by ! action ( ,*lor9e ! ,hydrog5 may be remov$ 9 ! =m ( ,hydro*loric ,acid1 & an equal numb] ( atoms ( ,*lor9e be sub/itut$4 ,9 ?is way a new comp\nd is =m$1 t]m$ ,*loracetic ,acid1 resembl+ 9 _m important p>ticul>s ! ,acetic ,acid itself4 ,notice p>ticul>ly t ! peculi> prop]ties *>act]i/ic ( ,*lor9e are completely mask$ 9 ! sub/itution body1 & no indication ( its pres5ce is obta9$ by ! usual te/s6 ,a soluble ,*loride gives ) ,nitrate ( ,silv] a :ite precipitate ( ,*loride ( ,silv]1 unaffect$ by ,acids1 b ! ,*loracetic ,acid does n2 h5ce x is pla9 t ! ,*lor9e exi/s 9 a peculi> & ,ultimate /ate ( comb9ation diff]5t f :at is usual4 ,! sub/ance we h be5 previ\sly consid]+1 viz4 ,pyroxyl9e1 af=ds ano!r illu/ration ( ! ,law ( ,sub/itution4 ,omitt+1 = ! sake ( simplicity1 ! numb] ( atoms conc]n$ 9 ! *ange1 ! action ( conc5trat$ ,nitric ,acid ^u ligne\s fibre may be ?us expla9$3-- ,c>bon ,cotton or ,hydrog5 ,nitric ,acid ,hydrog5 ,oxyg5 equals ,c>bon ,pyroxyl9e or ,hydrog5 ,wat] ,p]oxide ,nitrog5 ,oxyg5 ,or 9 symbols3-- ,,*#aa,o ,,no#e ,c 7,hn-#a,,no#d7 ,o ,,ho ,by a ref]5ce to ! =mula1 x is se5 t ! fif? atom ( ,oxyg5 conta9$ 9 ! ,nitric ,acid takes "o ( ,hydrog51 & =ms an atom ( ,wat]2 ! ,,no#d !n /eps 91 to fill ! gap :i* ! atom ( ,hydrog5 has left4 ,all ?is is done ) s little di/urbance t ev5 ! fibr\s /ructure ( ! cotton rema9s z be=e4 b4 ,*emical ,composition ( ! v>ieties ( ,pyroxyl9e4--,mr4 ,had[ has succe$$ 9 e/abli%+ f\r diff]5t sub/itution comp\nds1 :i*1 z no di/9ctive nom5clature has be5 at pres5t propos$1 may be t]m$ comp\nds ,a1 ,b1 ,c1 & ,d4 ,comp\nd ,a is ! mo/ explosive ,gun-,cotton1 & conta9s ! l>ge/ am\nt ( ,p]oxide ( ,nitrog54 ,x dissolves only 9 ,acetic ,e!r1 & is left on evaporation z a :ite p[d]4 ,x is produc$ by ! /ronge/ ,nitro-,sulphuric ,acid :i* c be made4 ,comp\nds ,b & ,c1 ei!r sep>ate or 9 a /ate ( mixture1 =m ! soluble mat]ial employ$ by ! ,photograph]4 ,!y bo? dissolve 9 ,acetic ,e!r1 & also 9 a mixture ( ,e!r & ,alcohol4 ,! latt]1 viz4 ,c1 also dissolves 9 glacial ,acetic ,acid4 ,!y are produc$ by a ,nitro-,sulphuric ,acid slightly weak] ?an t us$ = ,a1 & conta9 a small] am\nt ( ,p]oxide ( ,nitrog54 ,comp\nd ,d resembles :at has be5 t]m$ ,xyloid9e1 t is1 ! sub/ance produc$ by act+ ) ,nitric ,acid ^u ,/>*4 ,x conta9s less ,p]oxide ( ,nitrog5 ?an ! o!rs1 & dissolves 9 ,e!r & ,alcohol1 & also 9 ,acetic ,acid4 ,! e!real solution leaves1 on evaporation1 an opaque film1 :i* is highly combu/ible1 b n explosive4 ,by be>+ 9 m9d ! prop]ties ( ^! comp\nds1 _m ( ! anomalies compla9$ ( 9 ! manufacture ( ,gun-,cotton disappe>4 ,if ! ,nitro-,sulphuric ,acid employ$ is too /rong1 ! product w be insoluble 9 ,e!r2 :il/ if x is too weak1 ! fibres are gelat9iz$ by ! ,acid & p>tly dissolv$4 c4 ,means adopt$ to procure a ,nitro-,sulphuric ,acid ( ! requisite /r5g? = prep>+ ,pyroxyl9e4--,?is is a po9t ( m difficulty ?an w\ld at fir/ appe>4 ,x is easy to det]m9e an exact =mula = ! mixture1 b n s easy to hit ^u ! prop] proportions ( ! acids requir$ to produce t =mula2 & a v slight dep>ture f !m altoge!r modifies ! result4 ,! ma9 difficulty lies 9 ! unc]ta9 /r5g? ( comm]cial ,nitric ,acid4 ,oil ( ,vitriol is m to be dep5d$ ^u1 & has a tol]ably uni=m ,sp4 ,gr4 ( #ahcf2ac b ,nitric ,acid is con/antly liable to v>iation2 h5ce x becomes necess>y to make a prelim9>y det]m9ation ( its real /r5g?1 :i* is done ei!r by tak+ ! specific gravity & ref]r+ to tables1 or1 bett] /ill1 by a direct analysis4 ,z ea* atom ( ,sulphuric ,acid removes only a giv5 quantity ( wat]1 x foll[s t ! weak] ! ,nitric ,acid1 ! l>g] ! am\nt ( ,sulphuric :i* w be requir$ to br+ x up to ! prop] degree ( conc5tration4 #ac ,! lat] exp]i5ce ( ! writ] induces him to believe1 t ! specific gravity ( ,oil ( ,vitriol _c always be tak5 z an indication ( its real /r5g?2 :i* is be/ asc]ta9$ by analysis4 ,to avoid ! tr\ble necess>ily att5dant ^u ^! prelim9>y op]ations1 _m pref] to use1 9 place ( ,nitric ,acid itself1 "o ( ! salts =m$ by ! comb9ation ( ,nitric ,acid ) an alkal9e base4 ,! composition ( ^! salts1 provid$ !y are pure & nicely cry/alliz$1 c be dep5d$ on4 ,nitrate ( ,pota%1 or ,saltpetre1 conta9s a s+le atom ( ,nitric ,acid unit$ ) "o ( ,pota%4 ,x is an anhydr\s salt1 t is1 x has no wat] ( cry/allization4 ,:5 /rong ,sulphuric ,acid is p\r$ ^u ,nitrate ( ,pota% 9 a /ate ( f9e p[d]1 9 virtue ( its sup]ior *emical aff9ities x appropriates to itself ! ,alkali & lib]ates ! ,nitric ,acid4 ,if c>e be tak5 to add a suffici5t excess ( ! ,sulphuric ,acid1 a solution is obta9$ conta9+ ,sulphate ( ,pota% dissolv$ 9 ,sulphuric ,acid1 & free ,nitric ,acid4 ,! pres5ce ( ! ,sulphate ( ,pota% 7or1 m /rictly speak+1 ( ! ,bi-,sulphate7 does n 9 any way int]f]e ) ! result1 & ! effect is ! same z if ! mix$ acids !mselves _h be5 us$4 ,! reaction may be ?us repres5t$3-- ,nitrate ( ,pota% plus ,sulphuric ,acid 9 excess ,bisulphate ,pota% plus ,nitro-,sulphuric ,acid4 ,,*emi/ry ,,( ,,! ,,solution ,,( ,,pyroxyl9e ,,9 ,,e!r ,,& ,,alcohol1 ,,or ,,collodion4 ,! sub/itution comp\nds ,b & ,c1 already allud$ to z =m+ ! ,soluble ,cotton ( ,photograph]s1 are bo? abundantly soluble 9 ,acetic ,e!r4 ,?is liquid h[ev] is n adapt$ = ! purpose requir$1 inasmu* z on evaporation x leaves ! ,pyroxyl9e 9 ! =m ( a :ite p[d]1 & n z a transp>5t lay]4 ,! rectifi$ ,e!r ( comm]ce has be5 f\nd to answ] bett] ?an any o!r liquid z a solv5t = ,pyroxyl9e4 ,if ! sp4 gravity be ab\t #gej1 x conta9s inv>iably a small proportion ( ,alcohol1 :i* appe>s to be necess>y2 ! solution n tak+ place ) absolutely pure ,e!r4 ,! ,pyroxyl9e1 if prop]ly prep>$1 beg9s almo/ imm$iately to gelat9ize by ! action ( ! ,e!r1 & is soon completely dissolv$4 ,9 ?is /ate x =ms a slimy solution1 :i*1 :5 p\r$ out on a glass plate1 dries up into a horny transp>5t lay]4 ,9 prep>+ ,collodion = ,photographic purposes1 we f9d t its physical prop]ties are liable to consid]able v>iation4 ,sometimes x appe>s v ?9 & fluid1 fl[+ on ! glass almo/ l wat]1 :il/ at o!rs x is ?ick & glut9\s4 ,! causes ( ^! diff]5ces w n[ engage our att5tion4 ,!y may be divid$ into two classes3 fir/1 ^? relat+ to ! ,pyroxyl9e2 second1 to ! solv5ts employ$4 a4 ,v>iation ( ,prop]ties 9 diff]5t ,samples ( soluble ,pyroxyl9e4--,! sub/itution comp\nds ,a1 ,b1 ,c1 & ,d diff]1 z already %[n1 9 ! p]c5tage am\nt ( ,p]oxide ( ,nitrog5 pres5t1 & ! =m] are m explosive & insoluble ?an ! latt]4 ,b x (t5 happ5s 9 prep>+ ,pyroxyl9e1 t two portions ( ,nitro-,sulphuric ,acid tak5 f ! same bottle yield products :i* v>y 9 prop]ties1 al?\gh !y are necess>ily ! same 9 composition4 ,tak+ extremes 9 illu/ration1 we notice two pr9cipal modifications ( soluble ,pyroxyl9e4 ,! fir/1 :5 treat$ ) ! mixture ( ,e!r & ,alcohol1 s9ks d[n to a gummy or gelat9\s mass1 :i* gradually dissolves on agitation ,! solution is v fluid 9 proportion to ! numb] ( gra9s us$1 & :5 p\r$ out spreads into a beautifully smoo? & glassy surface1 :i* is q /ructureless1 ev5 :5 highly magnifi$4 ,! film adh]es tightly to ! glass1 & :5 ! f+] is drawn across x1 sep>ates 9 %ort fragm5ts1 & brok5 pieces4 ,! second v>iety produces a ,collodion :i* is ?ick & glut9\s1 fl[+ ov] ! glass 9 a slimy mann]1 & soon sett+ into num]\s small waves & cellul> spaces4 ,! film lies loose ^u ! glass1 is apt to contract on dry+1 & may be pu%$ (f by ! f+] 9 ! =m ( a connect$ sk94 ,?is subject is n ?or\ghly und]/ood1 b x is kn[n t ! temp]ature ( ! ,nitro-,sulphuric ,acid at ! "t ( imm]s+ ! ,cotton influ5ces ! result4 ,! soluble v>iety is produc$ by hot acids2 ! second1 or glut9\s1 by ! same acids employ$ cold1 or only slightly w>m4 ,! be/ temp]ature appe>s to be f #acj to #aee ,fahr5heit2 if x rises mu* beyond t po9t1 ! acids act ^u & dissolve ! ,cotton4 b4 ,! physical prop]ties ( ,collodion affect$ by ! proportions & purity ( ! ,solv5ts4--,pyroxyl9e ( ! v>ieties t]m$ ,b & ,c dissolves freely 9 a mixture ( ,e!r & ,alcohol2 b ! *>act]s ( ! result+ solution v>y ) ! relative proportions ( ! two solv5ts4 ,:5 ! ,e!r is 9 l>ge excess1 ! film is incl9$ to be /rong & t\gh1 s t x c (t5 be rais$ by "o corn] & lift$ completely (f ! plate )\t te>+4 ,x is also v contractile1 s t a portion ( ! ,collodion p\r$ on ! h& draws toge!r & puck]s ! sk9 z x dries4 ,if spread ^u a glass plate 9 ! usual way1 ! same prop]ty ( contractility causes x to retract & sep>ate f ! sides ( ! glass4 ,^! prop]ties1 produc$ by ,e!r 9 l>ge proportion1 disappe> entirely on ! addition ( m ,alcohol4 ,! transp>5t lay] is n[ s(t & easily torn1 possess+ b little coh]5cy4 ,x adh]es to ! surface ( ! glass m firmly1 & exhibits no t5d5cy to contract & sep>ate f ! sides4 ,f ^! rem>ks x w be ga!r$ t an excess ( ,e!r1 & a l[ temp]ature 9 prep>+ ! ,pyroxyl9e1 bo? fav\r ! production ( a contractile ,collodion2 :il/ on ! o!r h& an abundance ( ,alcohol1 & a hot ,nitro-,sulphuric ,acid1 t5d to produce a %ort & non-contractile ,collodion4 ,! physical prop]ties ( ,collodion are affect$ by ano!r cause1 viz4 by ! /r5g? & purity ( ! solv5ts1 or1 9 o!r words1 _! fre$om f dilution ) wat]4 ,if a few drops ( wat] be purposely add$ to a sample ( ,collodion1 ! effect is se5 to be to precipitate ! ,pyroxyl9e 9 flakes to ! bottom ( ! bottle4 ,!re are _m sub/ances kn[n 9 *emi/ry :i* are soluble 9 spiritu\s liquids1 b behave 9 ! same mann] z ,pyroxyl9e 9 ?is respect4 ,! mann] 9 :i* wat] ga9s entrance into ! ,photographic ,collodion is usually by ! employm5t ( ,alcohol or ,_s ( ,w9e :i* has n be5 highly rectifi$4 ,9 t case ! ,collodion is ?ick]1 & fl[s less readily ?an if ! ,alcohol 7 /rong]4 ,sometimes ! texture ( ! film left ^u evaporation is injur$2 x is no long] homog5e\s & transp>5t1 b semi-opaque1 reticulat$1 or honeycomb$1 & s rott5 t a /ream ( wat] project$ ^u ! plate wa%es x away4 ,^! effects are to be attribut$ n to ! ,alcohol1 b to ! wat] introduc$ ) x2 & ! rem$y w be to procure a /rong] _s1 or1 if t _c be done1 to increase ! am\nt ( ,e!r4 ,collodion prep>$ ) a l>ge proportion ( ,e!r1 & wat]1 b a small quantity ( ,alcohol1 is (t5 v fluid & /ructureless at fir/1 adh]+ to ! glass ) "s t5acity & hav+ a %ort texture2 b x t5ds to become rott5 :5 us$ to coat _m plates successively1 ! wat] on acc\nt ( its less] volatility accumulat+ 9 injuri\s quantity 9 ! la/ portions4 ,,! ,,coloration ,,( ,,iodiz$ ,,collodion ,,expla9$4 ,collodion iodiz$ ) ! ,iodides ( ,potassium1 ,ammonium1 or ,z9c1 soon assumes a yell[ t9t1 :i* 9 ! c\rse ( a few days or weeks1 accord+ to ! temp]ature ( ! atmosph]e1 deep5s to a full br[n4 ,?is gradual coloration1 due to a developm5t ( ,iod9e1 is caus$ p>tly by ! ,e!r & p>tly by ! ,pyroxyl9e4 ,e!r may1 ) prop] precautions1 be pres]v$ = a long "t 9 a pure /ate1 b on exposure to ! jo9t action ( air & light x und]goes a sl[ process ( oxidation1 att5d$ ) =mation ( ,acetic ,acid & a peculi> pr9ciple resembl+ 9 prop]ties ozone1 or ,oxyg5 9 an allotropic & active condition4 ,iodide ( ,potassium or ,ammonium is decompos$ by ,e!r 9 ?is /ate4 ,acetate ( ! ,alkali1 & ,hydriodic ,acid 7,,hi71 be+ fir/ produc$4 ,! ozoniz$ sub/ance !n removes ,hydrog5 f ! latt] comp\nd1 & lib]ates ,iod9e1 :i* dissolves & t+es ! liquid yell[4 ,a simple solution ( an ,alkal9e ,iodide 9 ,alcohol & ,e!r does n1 h[ev]1 become s quickly col\r$ z ,iodiz$ ,collodion2 & h5ce x is evid5t t ! pres5ce ( ! ,pyroxyl9e produces an effect4 ,x may be %[n t ,alkal9e ,iodides sl[ly decompose ,pyroxyl9e1 & t a portion ( ,p]oxide ( ,nitrog5 is set free3 ?is body1 conta9+ loosely comb9$ oxyg51 t5ds p[]fully to elim9ate ,iod9e1 z may be se5 by add+ a few drops ( ! yell[ comm]cial ,nitr\s acid to a solution ( ,iodide ( ,potassium4 ,! /ability ( ! p>ticul> ,iodide us$ 9 ,iodiz+ ,collodion1 influ5ces ma9ly ! rate ( coloration1 ?\gh elevation ( temp]ature & exposure to light are n )\t effect4 ,iodide ( ,ammonium is ! lea/ /able1 & ,iodide ( ,cadmium ! mo/ s2 ,iodide ( ,potassium be+ int]m$iate4 ,collodion iodiz$ ) pure ,iodide ( ,cadmium usually rema9s ne>ly col\rless to ! la/ drop1 if kept 9 a cool & d>k place4 ,z ! pres5ce ( free ,iod9e 9 ,collodion affects its photographic prop]ties1 x may sometimes be necess>y to remove x4 ,?is is done by ins]t+ a /rip ( ,silv]-foil2 :i* decolorizes ! liquid1 by =m+ ,iodide ( ,silv]1 soluble 9 ! excess ( ,alkal9e ,iodide 7p4 #db74 ,metallic ,cadmium1 & metallic ,z9c1 h ! same effect4 ,:5 ,me?ylat$ ,spirits are employ$ 9 ! manufacture ( ,collodion1 ! ,iod9e fir/ lib]at$ is aft]w>ds ei!r p>tially or entirely reabsorb$1 ! liquid acquir+ at ! same "t an acid reaction to te/-pap]4 ,,section ,,ii4 ,! ,*emi/ry ( ! ,nitrate ,ba?4 ,! solution ( ,nitrate ( ,silv] 9 :i* ! plate coat$ ) iodiz$ ,collodion is dipp$1 to =m ! lay] ( ,iodide ( ,silv]1 is kn[n te*nically z ! ,nitrate ,ba?4 ,! *emi/ry ( ,nitrate ( ,silv] has be5 expla9$ at page #ac1 b !re are "s po9ts relat+ to ! prop]ties ( its aque\s solution :i* require a fur!r notice4 ,solubility ( ,iodide ( ,silv] 9 ! ,nitrate ,ba?4--,aque\s solution ( ,nitrate ( ,silv] may be m5tion$ 9 ! li/ ( solv5ts ( ,iodide ( ,silv]4 ,! proportion dissolv$ is 9 all cases small1 b x increases ) ! /r5g? ( ! solution4 ,if no att5tion 7 paid to ?is po9t1 & ! precaution ( previ\sly saturat+ ! ,nitrate ,ba? ) ,iodide ( ,silv] neglect$1 ! film w\ld be dissolv$ :5 left too long 9 ! liquid4 ,?is solv5t p[] ( ,nitrate ( ,silv] on ! ,iodide is well %[n by tak+ ! excit$ ,collodion plate out ( ! ,ba?1 & all[+ x to dry spontane\sly4 ,! lay] ( ,nitrate on ! surface1 becom+ conc5trat$ by evaporation1 eats away ! film1 s z to produce a transp>5t1 spott$ appe>ance4 ,9 ! solution ( ,iodide ( ,silv] by ,nitrate ( ,silv] a d\ble salt is =m$1 :i* corresponds 9 prop]ties to ! d\ble ,iodide ( ,potassium & ,silv] 9 be+ decompos$ by ! addition ( wat]4 ,consequ5tly1 9 ord] to saturate a ,ba? ) ,iodide ( ,silv] x is only necess>y to dissolve ! total weight ( ,nitrate ( ,silv] 9 a small bulk ( wat]1 & to add to x a few gra9s ( an ,iodide2 p]fect solution takes place1 & on subsequ5t dilution ) ! full am\nt ( wat]1 ! excess ( ,iodide ( ,silv] is precipitat$ 9 ! =m ( a milky deposit4 ,acid condition ( ,nitrate ( ,silv]4--,a solution ( pure ,nitrate ( ,silv] is neutral to blue litmus-pap]1 b t prep>$ f ! comm]cial ,nitrate has usually an acid reaction2 ! cry/als hav+ be5 imp]fectly dra9$ f ! acid "m-liquor 9 :i* !y 7 =m$4 ,h5ce1 9 mak+ a new ,ba? x is (t5 advisable n only to saturate x ) ,iodide ( ,silv]1 b to neutralize ! free ,nitric acid x conta9s4 ,!re is also a peculi> condition ( ,nitrate ( ,silv] cry/alliz$ f a solution ( ! metal 9 ,nitric ,acid1 :i* r5d]s x q unfit = photographic purposes 7see p4 #aja74 ,x is ?\ght to dep5d ^u ! pres5ce ( an oxide ( ,nitrog51 possibly ( ,nitr\s ,acid1 & ! rem$y is to dry ! cry/als v /rongly1 or1 bett] /ill1 to fuse !m at a mod]ate heat3 m]e neutralization ) ,c>bonate ( ,soda does n suffice4 ,9 melt+ ,nitrate ( ,silv] great c>e %\ld be tak5 n to raise ! heat s high z to decompose ! salt1 or a basic ,nitrite w be =m$1 :i* affects ! prop]ties ( ! solution 7p4 #ac73 fus$ ,nitrate ( ,silv] ought1 :5 cold1 to be q :ite1 & to dissolve p]fectly 9 wat] )\t leav+ any residue4 ,! only objection to ! employm5t ( ,nitrate ( ,silv] 9 ?is =m is ! facility ) :i* x may be adult]at$ ) ,nitrates ( ,pota% & ,soda1 ! pres5ce ( :i* w\ld less5 ! available /r5g? ( ! ,ba?4 ,! ,nitrate ,ba?1 al?\gh p]fectly neutral :5 fir/ prep>$1 may become acid by cont9u$ use1 if ,collodion conta9+ mu* free ,iod9e be con/antly employ$4 ,9 t case a portion ( ,nitric ,acid is lib]at$1 ?us3-- ,nitrate ( ,silv] ,iod9e ,iodide ( ,silv] ,nitric ,acid ,oxyg54 ,:5 ,collodion is iodiz$ entirely ) alkal9e ,iodides1 x lib]ates ,iod9e by keep+2 & h5ce ! occasional use ( ,ammonia may be requir$ to remove acidity f ! ,ba?4 ,b s9ce ! introduction ( ! ,iodide ( ,cadmium1 :i* pres]ves ! ,collodion ne>ly or q col\rless1 ! necessity = neutraliz+ ,nitric ,acid 9 ! ,ba? has ceas$4 ,alkal9e condition ( ! ,ba?4--,by alkal9ity ( ! ,ba? is meant a condition 9 :i* ! blue t9t is rapidly re/or$ to r$d5$ litmus-pap]4 ,?is indicates t an ,oxide ( "s k9d is pres5t 9 solution1 :i*1 by comb9+ ) ! acid 9 ! r$d5$ pap]1 neutralizes x & removes ! r$ col\r4 ,if a small portion ( cau/ic ,pota% or ,ammonia be add$ to a /rong solution ( ,nitrate ( ,silv]1 x produces a br[n precipitate1 :i* is ,oxide ( ,silv]4 ,ammonia ,nitrate ( ,silv] ,oxide ( ,silv] ,nitrate ,ammonia4 ,! solution h[ev]1 f :i* ! precipitate has sep>at$1 is n left 9 a neutral /ate1 b possesses a fa9t alkal9e reaction4 ,oxide ( ,silv] & ,c>bonate ( ,silv] are also abundantly soluble 9 wat] conta9+ ,nitrate ( ,ammonia2 :i* salt is cont9ually accumulat+ 9 ! ,ba? :5 comp\nds ( ,ammonium are us$ = iodiz+4 ,an alkal9e ,ba? is p]haps ( all conditions ! "o mo/ fatal to success 9 photography4 ,x leads to t univ]sal d>k5+ ( ! film on apply+ ! develop] to :i* ! "n ( fogg+ has be5 giv54 ,h5ce c>e mu/ be us$ 9 add+ to ! ,ba? sub/ances :i* t5d to make x alkal9e4 ,collodion conta9+ free ,ammonia1 (t5 sold 9 ! %ops1 gradually does s4 ,! use ( ,pota%1 ,c>bonate ( ,soda1 ,*alk1 or ,m>ble1 to remove free ,nitric ,acid f ! ,ba?1 has ! same effect2 & h5ce1 :5 !y are employ$1 a trace ( ,acetic acid mu/ aft]w>ds be add$4 ,! mode ( te/+ a ba? = alkal9ity is z foll[s3-- a /rip ( por\s blue litmus-pap] is tak5 & held to ! m\? ( a bottle ( glacial ,acetic acid until x becomes r$d5$2 x is !n plac$ 9 ! liquid to be exam9$ & left = t5 m9utes or a qu>t] ( an h\r4 ,if ,oxide ( ,silv] be pres5t 9 solution1 ! orig9al blue col\r ( ! pap] w sl[ly b gradually be re/or$4 ,occasional =mation ( ,acetate ( ,silv] 9 ! ,nitrate ,ba?4--,9 prep>+ a new ,ba?1 if ! cry/als ( ,nitrate ( ,silv] are acid1 x is usual to add an alkali 9 small quantity4 ,?is removes ! ,nitric ,acid1 b leaves ! solution fa9tly alkal9e4 ,acetic ,acid is !n dropp$ 91 :i*1 by comb9+ ) ! ,oxide ( ,silv]1 =ms ,acetate ( ,silv]4 ,acetate ( ,silv] is n =m$ by ! simple addition ( ,acetic ,acid to ! ,ba?1 because its production "u su* circum/ances w\ld imply ! lib]ation ( ,nitric ,acid2 b if an alkali be pres5t to neutralize ! ,nitric ,acid1 !n ! d\ble decomposition takes place1 ?us-- ,acetate ( ,ammonia ,nitrate ( ,silv] ,acetate ( ,silv] ,nitrate ( ,ammonia4 ,acetate ( ,silv] is a :ite flaky salt1 sp>+ly soluble 9 wat]4 ,x dissolves 9 ! ,ba? only 9 small proportion1 b yet suffici5tly to affect ! ,photographic prop]ties ( ! film 7see p4 #aaa & #aag74 ,! obs]vance ( ! foll[+ simple rules w obviate its production 9 injuri\s quantity3--,fir/1 :5 x is requir$ to remove free ,nitric ,acid f a ba? n conta9+ ,acetic ,acid a solution ( ,pota% or ,c>bonate ( ,soda may be dropp$ 9 freely2 b ! liquid mu/ be filt]$ be=e add+ any ,acetic ,acid1 o!rwise ! br[n deposit ( ,oxide ( ,silv] w be tak5 up by ! ,acetic ,acid1 & ! ,ba? w be *>g$ ) ,acetate ( ,silv]4 ,secondly1 9 deal+ ) a ,ba? conta9+ bo? ,nitric & ,acetic ,acids1 employ an alkali mu* dilut$ 7,liquor ,ammoni ) #aj p>ts ( ,wat]71 & add a s+le drop at a "t1 coat+ & try+ a plate betwe5 ea* addition2 ! ,nitric ,acid w neutralize itself be=e ! ,acetic1 & ) c>e !re w be no =mation ( ,acetate ( ,silv] 9 quantity4 ,sub/ances :i* decompose ! ,nitrate ,ba?4--,mo/ ( ! common metals1 hav+ sup]ior aff9ity = ,oxyg51 sep>ate ! ,silv] f a solution ( ! ,nitrate2 h5ce ! ,ba? mu/ be kept 9 glass1 porcela91 or gutta-p]*a1 & contact ) ,iron1 ,copp]1 ,m]cury1 etc41 mu/ be avoid$1 or ! liquid w be discol\r$1 & a black deposit ( metallic ,silv] precipitat$4 ,all develop+ ag5ts1 su* z ,gallic & ,pyrogallic ,acids1 ! ,protosalts ( ,iron1 etc41 black5 ! ,nitrate ,ba?1 & r5d] x useless by r$uc+ metallic ,silv]4 ,*lorides1 ,iodides1 & ,bromides produce a deposit 9 ! ,ba?2 b ! solution1 al?\gh weak5$1 may aga9 be us$ aft] pass+ ?r\gh a filt]4 ,hyposulphites1 ,cyanides1 & all fix+ ag5ts decompose ,nitrate ( ,silv]4 ,organic matt]s1 g5]ally1 r$uce ,nitrate ( ,silv]1 ei!r ) or )\t ! aid ( light4 ,grape ,sug>1 ,album51 ,s]um ( ,milk conta9+ case9e1 etc41 black5 ! ,ba?1 ev5 9 ! d>k4 ,alcohol & ,e!r act m sl[ly1 & produce no injuri\s effect unless ! liquid is con/antly expos$ to light4 ,^! facts indicate t ! ,nitrate ,ba? conta9+ volatile organic matt]s mu/ be pres]v$ 9 a d>k place2 also t x %\ld be kept exclusively = s5sitiz+ ! ,collodion plates1 & n us$ 9 float+ pap]s int5d$ = ! pr9t+ process4 ,*anges 9 ! ,nitrate ,ba? by use4--,! solution ( ,nitrate ( ,silv] employ$ 9 excit+ ! ,collodion film gradually decreases 9 /r5g?1 b n s quickly z ! ,ba? us$ 9 s5sitiz+ pap]s = pr9t+4 ,if ! am\nt ( ,nitrate be all[$ to fall z l[ z tw5ty gra9s to ! ounce ( wat]1 ! decomposition w be imp]fect1 & ! film w be pale & blue1 ev5 ) a highly iodiz$ ,collodion4 ,a gradual accumulation ( ,e!r & ,alcohol also takes place 9 ! ,ba? aft] long use1 9 consequ5ce ( :i* ! develop+ solutions fl[ less readily ^u ! ,collodioniz$ plates1 & oily /a9s are apt to be produc$4 ,dim9i%$ s5sitiv5ess ( ! ,iodide film is sometimes trac$ to impurities 9 ! ,ba?1 :5 x is v old1 & has be5 mu* us$4 ,^! are probably ( an organic nature & may (t5 be p>tially remov$ by agitation ) kaol91 or animal *>coal4 ,! latt] h[ev] is objectionable1 be+ usually contam9at$ ) ,c>bonate ( ,lime1 :i* makes ! ,ba? alkal9e2 or 79 ! case ( purifi$ animal *>coal7 ) traces ( ,hydro*loric ,acid1 :i* lib]ate ,nitric ,acid 9 ! ,ba?4 ,ev5 ! kaol9 may z a prelim9>y precaution be wa%$ ) dilute ,acetic ,acid to remove ,c>bonate ( ,lime if any %\ld be pres5t4 ,,section ,,iii4 ,! ,conditions :i* affect ! ,=mation & ,developm5t ( ! ,lat5t ,image 9 ! ,collodion process4 ,x w be necess>y to preface ! obs]vations conta9$ 9 ?is ,section by def9+ two t]ms :i* are frequ5tly conf\nd$ ) ea* o!r1 b are 9 reality ( di/9ct mean+4 ,^! t]ms are ,s5sitiv5ess & ,int5sity4 ,by ,s5sitiv5ess is meant a facility ( receiv+ impression f v feeble rays ( light1 or ( receiv+ x quickly f bright] rays4 ,int5sity1 on ! o!r h&1 relates to ! appe>ance ( ! f9i%$ ,photograph1 indep5d5tly ( ! "t tak5 to produce x1--to ! degree ( opacity ( ! image1 & ! ext5t to :i* x ob/ructs transmitt$ light4 ,x w be se5 z we proce$ t ! conditions necess>y to obta9 extreme s5sitiv5ess ( ! ,iodide film are diff]5t f1 & (t5 oppos$ to1 ^? :i* give ! maximum int5sity ( image4 ,,causes ,,:i* ,,influ5ce ,,! ,,s5sitiv5ess ,,( ,,iodide ,,( ,,silv] ,,on ,,collodion4 ,"s ( ! mo/ important are z foll[s3-- a4 ,! pres5ce ( free ,nitrate ( ,silv]4--,:5 ! s5sitive film is remov$ f ! ,nitrate ,ba?1 ! ,iodide ( ,silv] is left 9 contact ) excess ( ,nitrate ( ,silv]4 ,! pres5ce ( ?is comp\nd is n ess5tial to ! action ( ! light1 s9ce1 if x be remov$ by wa%+ 9 di/ill$ wat]1 ! image may /ill be impress$4 ,9 su* a case h[ev] ! effect is produc$ sl[ly1 & a long] exposure 9 ! ,cam]a is requir$4 ,! s5sitiv5ess ( ! ,iodide film does n increase uni=mly ) ! am\nt ( ! excess ( ,nitrate ( ,silv]1 z measur$ by ! /r5g? ( ! ,ba?4 ,x is f\nd t no advantage 9 ?is respect c be ga9$ by us+ a proportion ( ,nitrate ( ,silv] great] ?an #cj or #ce gra9s to ! ounce ( wat]1 al?\gh solutions ( ?ree times ?is /r5g? h be5 sometimes employ$4 ,x has be5 ass]t$ t a *emically pure ,iodide ( ,silv]1 :i* is unaffect$ 9 col\r by ! direct action ( light1 is also incapable ( receiv+ ! invisible image 9 ! ,cam]a2 & t ! s5sitiv5ess ( a wa%$ ,collodion film is due to a m9ute quantity ( ,nitrate ( ,silv] /ill rema9+4 ,iodide ( ,silv] 9 ! /ate 9 :i* x is ?r[n d[n on dilut+ ) wat] a /rong solution ( ! salt kn[n z ! d\ble ,iodide ( ,potassium & ,silv]1--& :i* mu/1 f ! mode ( its prep>ation1 be free f ,nitrate ( ,silv]1--is q ins5sitive2 b ?is =m ( ,iodide diff]s f ! o!r 9 col\r1 & n only s1 b is likely to conta9 an excess ( ,iodide ( ,potassium4 ,! application ( a solution ( ,nitrate ( ,silv] to ?is comp\nd at once r5d]s x s5sitive to light4 b4 ,free acids 9 ! ,nitrate ,ba?4--,/rong oxidiz+ ag5ts1 su* z ,nitric ,acid1 greatly dim9i% ! s5sibility ( ! film1 & h5ce ! importance ( remov+ ! free acid (t5 met ) 9 comm]cial samples ( ! ,nitrate ( ,silv]4 ,! effect ( ev5 a s+le drop ( /rong ,nitric ,acid 9 an eight-ounce ,nitrate ,ba? w be appreciable2 & :5 ! proportion is increas$ to "o drop p] ounce1 x w be difficult to obta9 a rapid impression4 ,acetic ,acid has f> less effect ^u ! s5sitiv5ess ?an ,nitric ,acid1 & be+ f\nd useful dur+ ! developm5t ( ! image is commonly employ$2 b :5 great rapidity is desir$1 x %\ld be add$ cauti\sly1 & 9 a proportion v mu* less ?an t 9 ! solution kn[n z ! ,aceto-,nitrate ( ,silv]1 :i* conta9s ab\t "o drop ( ! glacial acid to ea* gra9 ( ,nitrate ( ,silv]4 c4 ,addition ( c]ta9 organic matt]s4--,x has long be5 rem>k$ t ! use ( bodies l ,album51 ,gelat9e1 ,case9e1 etc41 :i* comb9e ) ,oxides ( ,silv]1 ret>d ! action ( light ^u ,iodide ( ,silv]2 & ! rec5t obs]vations ( ! ,au?or enable him to confirm ?is /atem5t4 ,x is probable t "o cause1 among/ o!rs1 ( ! great s5sibility ( ! ,collodion film is due to ! fact t ,pyroxyl9e is a sub/ance peculi>ly indiff]5t to ! ,salts ( ,silv]1 exhibit+ no t5d5cy to r$uce !m to ! metallic /ate2 & x is prov$ by exp]im5t t ! addition ( ,grape ,sug>1 or ( ! res9\s body1 ,glycyrrhiz9e1 :i* resembles ,album5 9 caus+ a :ite precipitate 9 /rong solution ( ,nitrate ( ,silv]1 r5d]s necess>y a long] exposure 9 ! ,cam]a4 ,alkal9e ,citrates h a /ill m m>k$ effect1 z also h ,t>trates1 ,oxalates1 etc4 d4 ,impurities 9 ! soluble ,iodides4--,comm]cial ,iodide ( ,potassium (t5 conta9s ,iodate ( ,pota%1 :i* is f\nd to h a ret>d+ effect ^u ! action ( light2 also ,c>bonate ( ,pota%1 :i*1 9 ,collodion1 produces ,iod(orm1#ad & 9 ! pap] processes1 :]e ,aceto-,nitrate is us$ = s5sitiz+1 =ms ,acetate ( ,silv]4 ,iod(orm has a m>k$ influ5ce 9 dim9i%+ ! s5sitiv5ess ( ,iodide ( ,silv]2 ,acetate ( ,silv] may p]haps increase x a little by secur+ ! abs5ce ( free ,nitric ,acid 7p4 #aag74 ,iodide ( ,potassium prep>$ by ! process 9 :i* ,sulphurett$ ,hydrog5 & ,alcohol are us$1 & hav+ a smell ( ,g>lic1 conta9s probably ,xan?ate ( ,pota%1 & is ne>ly useless = ,photography4 #ad ,see ! ,vocabul>y1 ,"p ,,iii41 ,art4 ,iod(orm4 ,comm]cial ,iodide ( ,cadmium is a pur] salt ?an ! ,iodide ( ,potassium1 & may be advantage\sly sub/itut$ = x2 b x possesses ! prop]ty ( coagulat+ ,album51 & h5ce _c be employ$ 9 conjunction ) t sub/ance4 e4 ,pres5ce ( free ,iod9e4--,bo? 9 ! wax$ pap] & ! ,collodion processes1 ! solutions (t5 conta9 a small quantity ( free ,iod9e4 ,?is ,iod9e1 9 contact ) ! ,nitrate ( ,silv] ( ! ,ba?1 produces a mix$ ,iodide & ,iodate ( ,silv]1 & lib]ates ,nitric ,acid4 ,x ?us ret>ds ! s5sitiv5ess ( ! film 9 proportion to ! quantity ( ,iod9e pres5t4 ,collodion ( a full yell[ col\r is p]ceptibly less s5sitive ?an ! same r5d]$ col\rless2 & :5 en\gh ,iod9e has be5 lib]at$ to give a r$ or br[n t9t1 d\ble ! orig9al exposure w probably be requir$4 ,if br[n ,collodion be mu* us$1 ! ,nitrate ,ba? may by degrees become suffici5tly contam9at$ ) free ,nitric ,acid to int]f]e ) ! s5sitiv5ess ( ! film2 b if col\rless or lemon-yell[ t9t$ ,collodion be employ$1 ?is evil ne$ n be anticipat$4 ,c]ta9 sub/ances may be add$ to col\r$ ,collodion :i* possess ! prop]ty ( c\nt]act+ ! ret>d+ influ5ce ( ! free ,iod9e1 su*1 = in/ance1 z ! ,oils ( ,cloves1 ,c9namon1 etc42 !y probably act 9 virtue ( _! aff9ity = ,oxyg51 by prev5t+ ! =mation ( ,iodate ( ,silv]4 ,9 col\rless ,collodion !y produce little or no effect1 nei!r d !y remove ! ins5sitiv5ess ( ! film :5 dep5d5t ^u a too acid condition ( ! ,nitrate ,ba?4 f4 ,addition ( ,bromide or ,*loride to ,collodion4--,9 ! ,dagu]reotype a v exalt$ /ate ( s5sibility is obta9$ by expos+ ! silv]$ plate fir/ to ! vap\r ( ,iod9e1 & aft]w>ds to t ( ,brom9e or ,*lor9e2 b ?is rule does n apply to ! ,collodion process1 :i* diff]s ess5tially 9 pr9ciple4 ,soluble ,bromides add$ to ,collodion less5 its s5sibility to an appreciable ext5t1 z also d ,*lorides4 ,?is rule h[ev] may p]haps be liable to an exception :5 artificial light is us$1 :i* conta9s a great] proportion ( ! rays ( small refrangibility1 kn[n to act m p[]fully ^u ! ,bromide ?an ^u ! ,iodide ( ,silv] 7p4 #ff74 g4 ,d5sity ( ! s5sitive film4--,:5 ! proportion ( soluble ,iodide 9 ! iodiz+ solution is too great1 ! film is v d5se1 & ! ,iodide ( ,silv] is apt to bur/ out ^u ! surface1 & fall away 9 loose flakes into ! ,ba?4 ,?is condition1 :i* is highly unfav\rable to s5sitiv5ess1 is v common 9 ,collodion1 & con/itutes :at is t]m$ ov]-iodiz+4 ,! ,iodide1 9 fact1 is =m$ 9 su* a case too mu* ^u ! surface1 & consequ5tly1 :5 ! fix+ ag5t is appli$1 ! image n be+ reta9$ by ! film1 is wa%$ (f & lo/4 ,on ! o!r h&1 ! s5sibility ( ! film is n less5$ by r$uc+ ! am\nt ( ,iodide 9 ,collodion to a m9imum1 if all ! solutions are neutral2 b ! pale blue films =m$ by a dilute ,collodion1 & :i* almo/ rival ! ,dagu]reotype itself 9 delicacy1 are ne>ly useless 9 practice2 = if free ,iod9e or o!r bodies ( a ret>d+ nature are pres5t 9 any quantity1 ei!r 9 ! ,collodion or 9 ! ,ba?1 !y almo/ de/roy ! action ( a weak light1 produc+ a f> m injuri\s effect ?an if ! film 7 m yell[ & opaque4 h4 ,impurities 9 ,e!r & ,alcohol4--,pure ,e!r %\ld be neutral to te/-pap]1 b ! comm]cial samples ( ?is article h usually ei!r an acid or an alkal9e reaction4 ,! frequ5t occurr5ce ( a peculi> oxidiz+ pr9ciple 9 ,e!r has also be5 po9t$ out 7p4 #he74 ,ea* ( ^! ?ree conditions is injuri\s to s5sitiv5ess2 ! fir/ & la/ by lib]at+ ,iod9e :5 alkal9e ,iodides are us$2 & ! second1 by produc+ ,iod(orm "u ! same circum/ances4 ,9 ?is case ! ,collodion rema9s col\rless1 b gives inf]ior results4 ,! ,au?or has also obs]v$ t ,e!r :i* has be5 r$i/ill$ f ! residues ( ,collodion may conta9 a volatile pr9ciple 7probably a comp\nd ,e!r87 :i* produces a ret>d+ effect ^u ! action ( light4 ,comm]cial ,_s ( ,w9e is n always uni=m 9 composition1 z suffici5tly evid5c$ by ! te/ ( smell4 ,x may conta9 fusel oil or o!r volatile sub/ances1 :i* become milky on dilution ) wat]1 & are believ$ to injure ! quality ( ! _s = ,photographic use4 i4 ,relative proportions ( ,e!r & ,alcohol 9 ,collodion4--,x 0 %[n at p4 #hd t ! addition ( ,alcohol to ,collodion less5s ! contractility ( ! film1 & r5d]s x s(t & gelat9\s4 ,?is condition is fav\rable to ! =mation ( ! invisible image 9 ! ,cam]a1 ! play ( aff9ities be+ promot$ by ! loose mann] 9 :i* ! p>ticles ( ,iodide are held toge!r4 ,x is !re=e usual to add to ,collodion z mu* ,alcohol z x w be> )\t becom+ glut9\s1 or leav+ ! glass2 ! exact quantity requir$ v>y+ ) ! /r5g? ( ! _s or its fre$om f dilution ) wat]4 k4 ,decomposition 9 ! ,collodion4--,collodion iodiz$ ) ! metallic ,iodides g5]ally1 except+ ! ,iodide ( ,cadmium1 becomes br[n & loses s5sitiv5ess 9 ! c\rse ( a few days or weeks4 ,if ! free ,iod9e1 ! cause ( ! br[n col\r1 be remov$1 ! great] "p1 b n ! :ole1 ( ! s5sitiv5ess is rega9$4 ,! exp]im5ts ( ! ,au?or1 & ( o!rs1 h prov$ t a solution ( ,pyroxyl9e 9 contact ) an un/able iodide1 sl[ly und]goes decomposition1 ! result ( :i* is t ,iod9e is set free1 & an equival5t quantity ( ! base rema9s 9 union ) c]ta9 organic elem5ts ( ! ,collodion4 ,decomposition also gradually ensues :5 iodiz$ ,collodion is plac$ 9 contact ) r$uc+ ag5ts1 su* z ,proto-iodide ( ,iron1 ,gallic ,acid1 ,grape ,sug>1 ,glycyrrhiz9e1 etc41 s t ^! comb9ations d n reta9 a con/ant s5sibility = any l5g? ( "t4 ,ev5 pla9 ,collodion uniodiz$ _c be pres]v$ _m mon?s )\t a small b p]ceptible am\nt ( *ange4 l4 ,decomposition 9 ! ,nitrate ,ba?4--,a ,collodion ,nitrate ,ba? :i* has be5 mu* us$1 (t5 gives a less s5sitive film ?an :5 newly made4 ,x is kn[n also t _m organic sub/ances :i* r$uce ,nitrate ( ,silv]1 if add$ to ! ,ba?1 produce a /ate :i* is fav\rable to s5sitiv5ess :il/ ! decomposition is tak+ place1 b is ev5tually unfav\rable2 h5ce ! solution w be injur$ by add+ ei!r ,gallic or ,pyrogallic ,acid1 & by organic matt]s g5]ally if expos$ to light4 ,recapitulation4--,! conditions mo/ fav\rable to extreme s5sitiv5ess ( ! ,iodide ( ,silv] on ,collodion may be cond5s$ z foll[s3--p]fect neutrality ( ! solutions employ$2 a s(t1 gelat9\s /ate ( ! film2 abs5ce ( ,*lorides & o!r salts :i* precipitate ,nitrate ( ,silv]2 an undecompos$ ,collodion1 conta9+ no organic matt] ( t k9d :i* is precipitat$ by basic ,acetate ( ,lead1 & comb9es ) oxides ( ,silv]4 ,,! ,,conditions ,,:i* ,,affect ,,! ,,developm5t ,,( ,,! ,,lat5t ,,image4 ,! g5]al !ory ( ! developm5t ( a lat5t image by means ( a r$uc+ ag5t1 hav+ be5 simply expla9$ 9 ! ?ird ,*apt]1 may n[ be m fully exam9$ 9 its application to ! ,iodide ( ,silv] on ,collodion4 a4 ,! pres5ce ( free ,nitrate ( ,silv] ess5tial to ! developm5t4--,?is subject has already be5 m5tion$ 7p4 #cf74 ,a s5sitive ,collodion plate1 c>efully wa%$ 9 di/ill$ wat]1 is /ill capable ( receiv+ ! radiant impression 9 ! ,cam]a1 b x does n admit ( developm5t until x has be5 r$ipp$ 9 ! ,ba?1 or treat$ ) a r$uc+ ag5t to :i* ,nitrate ( ,silv] has be5 add$3 & if ! proportion ( free ,nitrate ( ,silv] on a ,collodion film be too small1 ! image w be feeble or altoge!r imp]fect 9 p>ts1 ) pat*es ( gre5 or blue1 due to defici5t r$uction4 b4 ,comp>ative /r5g? ( d$uc+ ,ag5ts4--,no increase ( p[] 9 a develop] w suffice to br+ out a p]fect image on an "u-expos$ plate1 or ^u a film conta9+ too little ,nitrate ( ,silv]4 ,b !re is consid]able diff]5ce 9 ! l5g? ( "t :i* ! v>i\s develop]s require to act4 ,gallic ,acid is ! mo/ feeble1 & ,pyrogallic ,acid ! /ronge/1 produc+ at lea/ f\r times m effect ?an an equal weight ( ! cry/alliz$ ,protosulphate ( ,iron1 & tw5ty times m ?an ! ,protonitrate ( ,iron4 c4 ,! effect ( free ,acid ^u ! developm5t4--,acids t5d to ret>d ! r$uction ( ! image z well z to dim9i% ! s5sibility ( ! film to light4 ,nitric ,acid especially does s1 f its p[]ful oxidiz+ & solv5t prop]ties4 ,! effect ( ,nitric ,acid is p>ticul>ly se5 :5 ! film ( ,iodide ( ,silv] is v blue & transp>5t1 & ! quantity ( ,nitrate ( ,silv] reta9$ ^u its surface small4 ,"u su* circum/ances ! prop] developm5t ( ! image may be susp5d$1 & spangles ( metallic ,silv] sep>ate4 ,?is indicates t ! quantity ( ! acid %\ld be dim9i%$1 or ! /r5g? ( ! ,nitrate ,ba? & ( ! r$uc+ ag5t be increas$1 z a c\nt]poise to ! ret>d+ action ( acid ^u ! developm5t4 ,acetic ,acid also mod]ates ! rapidity ( developm5t1 b x has n t t5d5cy altoge!r to susp5d x possess$ by ,nitric ,acid4 ,x is !re=e usefully employ$1 to enable ! op]ator to cov] ! plate ev5ly ) liquid be=e ! developm5t comm5ces1 & to pres]ve ! :ite p>ts ( ! impression f any accid5tal deposit ( metallic ,silv] due to irregul> action ( ! r$uc+ ag5t4 ,on comp>+ ! ret>d+ effects ( free acid ^u ! light's action1 & ^u ! developm5t1 we see t ! =m] is ! mo/ m>k$1--t a small quantity ( ,nitric ,acid produces a m decid$ influ5ce ^u ! impression ( ! image 9 ! ,cam]a ?an ^u ! br++ out ( t image by means ( a develop]4 d4 ,accel]at+ effect ( c]ta9 organic matt]s4--,organic bodies1 l ,album51 ,gelat9e1 ,glycyrrhiz9e1 etc41 :i* comb9e *emically ) oxides ( ,silv]1 & 7 %[n 9 ! la/ ,section to less5 ! s5sitiv5ess ( ! ,iodide film1--facilitate ! developm5t ( ! image1 produc+ (t5 a d5se deposit ( a br[n or black col\r by transmitt$ light4 ,9 ! same way1 viz4 by a ret5tion ( organic matt]1 may p>tly be expla9$ ! fact1 t ! image develop$ by ,pyrogallic ,acid1 al?\gh prov$ by ! application ( te/s to conta9 no m ?an an equal quantity ( ,silv]1 possesses great] opacity by transmitt$ light1 ?an t result+ f ! use ( protosalts ( ,iron3 & 9 ! case ( ! ,collodion itself ! same rule appli$--if x be pure1 x is liable to give a less vigor\s impression ?an :5 by long keep+ a p>tial decomposition has tak5 place1 & products h be5 =m$ :i* comb9e ) r$uc$ ,oxide ( ,silv] m easily ?an ! unalt]$ ,pyroxyl9e4 e4 ,molecul> conditions affect+ ,int5sity4--,! physical /ructure ( ! ,collodion film is ?\ght to ex]t an influ5ce ^u ! mode 9 :i* ! r$uc$ ,silv] is ?r[n d[n dur+ ! developm5t4 ,a %ort & almo/ p[d]y /ate1 su* z ,collodion iodiz$ ) ! alkal9e iodides acquires by keep+1 is consid]$ fav\rable1 & a glut9\s1 coh]5t /ructure unfav\rable1 to d5sity4 ,?is is c]ta9ly ! case :5 ! film is all[$ to dry be=e developm5t1 z 9 ! process ) desiccat$ ,collodion &1 to "s ext5t1 9 ! ,oxymel pres]vative process4 ,! mode ( conduct+ ! developm5t also affects ! d5sity2 a rapid action t5d+ to produce an image ( :i* ! p>ticles are f9ely divid$ & (f] a consid]able resi/ance to ! passage ( light1 :il/ a sl[ & prolong$ developm5t (t5 leaves a metallic & almo/ cry/all9e deposit1 comp>atively transluc5t & feeble4 ,! writ] has obs]v$1 t ) c]ta9 samples ( ,collodion ! image is mu* enfeebl$ by keep+ ! plate = a consid]able "t1--a qu>t] ( an h\r or long]1--aft] s5sitiz+1 b be=e developm5t4 ,?is effect is n ! result ( ! ,nitrate ( ,silv] hav+ p>tially dra9$ away1 s9ce a second dip 9 ! ,nitrate ,ba? imm$iately be=e apply+ ! ,pyrogallic ,acid1 does n rem$y x4 ,an alt]ation ( molecul> /ructure may !re=e be ! correct explanation1 & if s1 a contractile ,collodion w\ld suff] m ?an "o possess+ less coh]5cy4 ,! act9ic p[] ( ! light at ! "t ( tak+ ! picture1 influ5ces ! appe>ance ( ! develop$ image2 ! mo/ vigor\s impressions be+ produc$ by a /rong light act+ = a %ort "t4 ,on a dull d>k day1 or 9 copy+ badly light$ int]iors1 ! photograph w (t5 lack bloom & ri*ness1 & be blue & inky by transmitt$ light4 f4 ,developm5t ( images ^u ,bromide & ,*loride ( ,silv]4--,( ! ?ree pr9cipal ,salts ( ,silv]1 ! ,iodide is ! mo/ s5sitive to light1 b ! ,bromide & ,*loride1 "u "s conditions1 are m easily develop$ & give a d>k] image4 ,9 ! ,collodion process ! diff]5ce is pr9cipally se5 :5 organic bodies1 l ,grape ,sug>1 ,glycyrrhiz9e1 etc41 are introduc$ 9 ord] to increase ! int5sity2 a f> m decid$ effect be+ produc$ by add+ bo? ,glycyrrhiz9e & a portion ( ,bromide or ,*loride1 ?an by us+ ! ,glycyrrhiz9e alone4#ae #ae ,see ! ,au?or's ,pap] on ! *emical composition ( ! photographic image1 9 ! eigh? ,*apt]4 g4 ,! int5sity ( ! image affect$ by ! l5g? ( exposure4--,?is po9t has be5 briefly allud$ to 9 ! ?ird ,*apt]4 ,if ! exposure 9 ! ,cam]a be prolong$ beyond ! prop] "t ! developm5t takes place rapidly b )\t any int5sity1 ! picture be+ pale & transluc5t4 ,! effects produc$ by ov]-action ( ! light are p>ticul>ly se5 :5 ! ,nitrate ,ba? conta9s ,nitrite ( ,silv]1 or ,acetate ( ,silv]2 ! image be+ frequ5tly 9 su* a case d>k by reflect$ light1 & r$ by transmitt$ light1--m ne>ly resembl+ 9 fact a photographic pr9t1 develop$ on pap] prep>$ ) ,*loride ( ,silv]4 ,:5 ,collodion plates are coat$ ) honey )\t previ\sly remov+ ! free ,nitrate ( ,silv]1 a sl[ r$uc+ action is set up1 :i* may give rise to ! *>act]i/ic appe>ance above ref]r$ to1 aft] developm5t4 ,o!r organic sub/ances1 su* z bili>y matt]1 etc41 w act 9 ! same way4 h4 ,c]ta9 conditions ( ! ,ba? :i* affect developm5t4--,att5tion may be call$ to a peculi> /ate ( ! ,nitrate ,ba?1 9 :i* ! ,collodion image developes unusually sl[ly1 & has a dull grey metallic appe>ance1 ) an abs5ce ( int5sity 9 ! p>ts mo/ act$ on by ! light4 ,?is condition1 :i* occurs only :5 us+ a newly mix$ solution1 is ?\ght by ! ,au?or to dep5d ^u ! pres5ce ( an ,oxide ( ,nitrog5 reta9$ by ! ,nitrate ( ,silv]4 ,x is remov$ p>tially by neutraliz+ ! ,ba? ) an alkali1 m p]fectly s by add+ an excess ( alkali foll[$ by ,acetic ,acid2 b mo/ completely by c>efully fus+ ! ,nitrate ( ,silv] be=e dissolv+ x4 ,comm]cial ,nitrate ( ,silv] has sometimes a fragrant smell1 simil> to t produc$ by p\r+ /rong ,nitric ,acid ^u ,alcohol4 ,:5 su* is ! case1 x conta9s organic matt]1 & produces a ,ba? :i* yields r$ & mi/y pictures4 ,nitrate ( ,silv] :i* has be5 suffici5tly /rongly fus$ to decompose ! ,salt1 & produce a portion ( ! basic ,nitrite ( ,silv] exhibits great peculi>ity ( developm5t1 ! image com+ out in/antane\sly & ) great =ce4 ,?is condition is exactly ! rev]se ( t produc$ by ! pres5ce ( acids1 9 :i* ! developm5t is sl[ & gradual4 ,9 summ+ up ! diff]5t conditions ( ! ,nitrate ,ba? :i* affect ! developm5t ( ! image1 z _m z f\r might be m5tion$1 ea* ( :i* gives a m rapid r$uction ?an ! "o :i* prec$es x4 ,^! are--! acid ,nitrate ,ba?1 ! neutral ,ba?1 ! ,ba? ( /rongly fus$ ,nitrate ( ,silv]1 & ! ,ba? conta9+ ,ammoniacal ,nitrate ( ,silv]1 :i* is q unmanageable1 & produces an in/antane\s & univ]sal black5+ ( ! film on ! application ( ! develop]4 ,great] int5sity ( image is commonly obta9$ 9 a ,nitrate ,ba? :i* has be5 a long "t 9 use1 ?an 9 a newly mix$ solution3 ?is may be due to m9ute quantities ( organic matt] dissolv$ out ( ! ,collodion film1 :i*1 hav+ an aff9ity = ,oxyg51 p>tially r$uce ! ,nitrate ( ,silv]2 & also to ! accumulation ( ,alcohol & ,e!r 9 an old ,ba? produc+ a %ort & friable /ructure ( ! film4 i4 ,effect ( ,temp]ature on ,developm5t4--,r$uction ( ! oxides ( noble metals proce$s m rapidly 9 proportion z ! temp]ature rises4 ,9 cold wea!r x w be f\nd t ! developm5t ( ! image is sl[] ?an usual1 & t great] /r5g? ( ! r$uc+ ag5t & m free ,nitrate ( ,silv] is requir$ to produce ! effect4 ,on ! o!r h&1 if ! heat ( ! atmosph]e be excessive1 ! t5d5cy to rapid r$uction w be greatly increas$1 ! solutions decompos+ ea* o!r almo/ imm$iately on mix+4 ,9 ?is case ! rem$y w be to use ,acetic ,acid freely bo? 9 ! ,ba? & 9 ! develop]1 at ! same "t less5+ ! quantity ( ,pyrogallic ,acid1 & omitt+ ! ,nitrate ( ,silv] :i* is sometimes add$ t[>ds ! end ( ! developm5t4 ,also 9 ! case ( films :i* are to be kept = a long "t 9 a s5sitive condition by means ( honey1 etc41 ! modify+ influ5ce ( temp]ature mu/ be obs]v$1 & ! quantity ( free ,nitrate ( ,silv] left ^u ! film be r$uc$ to a m9imum if ! !rmomet] /&s high] ?an usual4 ,,section ,,iv4 ,on c]ta9 ,irregul>ities 9 ! ,develop+ ,process4 ,! *>act]i/ics ( ! prop] developm5t ( a lat5t image are--t ! action ( ! r$uc+ ag5t %\ld cause a black5+ ( ! ,iodide 9 ! p>ts t\*$ by light1 b produce no effect ^u ^? :i* h rema9$ 9 %ad[4 ,9 op]at+ bo? on ,collodion & pap] h[ev] !re is a liability to failure 9 ?is respect2 ! film beg9n+1 aft] ! application ( ! develop]1 to *ange 9 col\r to a great] or less ext5t ov] ! :ole surface4 ,!re are two ma9 causes :i* produce ?is /ate ( ?+s3--! fir/ be+ due to an irregul>ity 9 ! action ( ! light2 ! second to a faulty condition ( ! *emicals employ$4 ,if f a defect 9 ! con/ruction ( ! in/rum5t1 or f o!r causes :i* w be po9t$ out m p>ticul>ly 9 ! ,second ,"p ( ?is "w1 diffus$ :ite light ga9s entrance into ! ,cam]a1 x produces indi/9ctness ( ! image by affect+ ! ,iodide m or less univ]sally4 ,! lum9\s image ( ! ,cam]a n be+ p]fectly pure1 m]e ov]-exposure ( ! s5sitive plate w usually h ! same effect4 ,9 su* a case1 :5 ! develop] is p\r$ on1 a fa9t image fir/ appe>s1 & is foll[$ by a g5]al cl\d9ess4 ,! cle>ness ( ! develop$ ,collodion picture is mu* influ5c$ by ! condition ( all ! solutions employ$1 b p>ticul>ly s by t ( ! ,nitrate ,ba?4 ,if ?is liquid be 9 ! /ate t]m$ alkal9e 7p4 #hh71 x w be impossible to obta9 a good picture2 & ev5 :5 neutral1 c>e & avoidance ( all di/urb+ causes w be requir$ to prev5t a deposition ( ,silv] ^u ! %ad[s ( ! image3 especially s :5 ,nitrite ( ,silv] or ,acetate ( ,silv] are pres5t1 bo? ( ^! salts be+ m easily r$uc$ ?an ! ,nitrate ( ,silv]4 ,! use ( ,acid is ! pr9cipal res\rce 9 obviat+ cl\d9ess ( ! image4 ,acids less5 ! facility ( r$uction ( ! ,salts ( ,silv] by develop+ ag5ts 7p4 #ih71 & h5ce :5 !y are pres5t ! metal is deposit$ m sl[ly1 & only on ! p>ts :]e ! action ( ! light has s modifi$ ! p>ticles ( ,iodide z to fav\r ! decomposition3 :]eas if acids be abs5t or pres5t 9 insuffici5t quantity1 ! equilibrium ( ! mixture ( ,nitrate ( ,silv] & r$uc+ ag5t :i* con/itutes ! develop] is s un/able1 t any r\gh po9t or %>p edge is likely to become a c5tre f :i* ! *emical action1 once />t$1 radiates to all p>ts ( ! plate4 ,v>i\s acids h be5 employ$1 su* z ,acetic acid1 ,citric acid1 ,t>t>ic acid1 etc4 ,nitric acid is ! mo/ effectual ( all1 b is seldom us$1 because1 al?\gh ! image c (t5 be develop$ ) great cle>ness :5 ! ,ba? conta9s a small quantity ( ,nitric acid1 yet su* a condition is n fav\rable to int5sity2 on ! o!r h&1 films :i* are prone to irregul> r$uction1 su* z ^? prep>$ 9 a *emically neutral ba? or a ba? conta9+ ,acetate or ,nitrite ( ,silv]1 are likely to give ! greate/ vig\r ( impression4 ,h5ce1 :5 ?is quality is desir$1 ! use ( ,nitric ,acid w be adopt$ cauti\sly4 ,! /ate ( ! ,collodion mu/ be att5d$ to z well z t ( ! ba?2 x %\ld be ei!r acid or neutral1 n alkal9e4 ,col\rless ,collodion may be us$ successfully z a rule1 b sometimes a little free ,iod9e is advantage\sly add$4 ,c>e %\ld be tak5 9 introduc+ organic sub/ances1 _m ( :i* dissolve out into ! ba?1 & spoil x = giv+ cle> pictures4 ,glycyrrhiz9e1 h[ev]1 :i* is recomm5d$ to produce int5sity ( ,negatives1 has no effect ( t k9d1 & may be employ$ ) safety4 ,! condition ( ! develop+ ag5t is a po9t ( importance 9 produc+ cle> & di/9ct pictures4 ,! ,acetic acid1 :i* is advis$ 9 ! =mul1 _c be omitt$ or ev5 less5$ 9 quantity )\t dang]4 ,?is is p>ticul>ly ! case 9 hot wea!r or "u any o!r condition :i* fav\rs r$uction1 su* z neutrality ( ! ba?1 etc42 at all times1 9 fact1 :5 ! solutions ( ,pyrogallic acid & ,nitrate ( ,silv] decompose ea* o!r ) unusual rapidity4 ,9 addition to ! po9ts n[ m5tion$1 viz4 ! /ate ( ! ,ba?1 ( ! ,collodion1 & ( ! develop]1 ! read] %\ld also /udy ! rem>ks made 9 ! ,?ird ,section ( ,*apt] ,,iii4 on ! effect ( surface conditions 9 modify+ ! deposition ( vap\r & ( metallic ,silv]3 he w !n 9 all probability exp]i5ce b little difficulty 9 deal+ ) ^? num]\s irregul>ities 9 ! action ( ! develop+ fluid1 :i* (t5 prove ! greate/ h9drance to ! successful practice ( ! ,collodion process4 ,,*apt] ,,vii4 ,,on ,,positive ,,& ,,negative ,,collodion ,,photographs4 ,! t]ms ,positive & ,negative occur s frequ5tly 9 all works ^u ! subject ( ,photography1 t x w be impossible = ! /ud5t to make progress )\t ?or\ghly und]/&+ _! mean+4 ,a ,positive may be def9$ to be a ,photograph :i* gives a natural repres5tation ( an object1 z x appe>s to ! eye4 ,a ,negative ,photograph1 on ! o!r h&1 has ! lights & %ad[s rev]s$1 s t ! appe>ance ( ! object is *ang$ or negativ$4 ,9 ,photographs tak5 ^u ,*loride ( ,silv]1 ei!r 9 ! ,cam]a or by sup]position1 ! effect mu/ necess>ily be ,negative2 ! ,*loride be+ d>k5$ by lum9\s rays1 ! lights are repres5t$ by %ad[s4 ,! foll[+ simple diagrams w make ?is obvi\s4 ,illu/ration3 ,fig4 #a4 ,fig4 #b4 ,fig4 #c4 ,fig4 #a is an opaque image drawn ^u a transp>5t gr\nd2 fig4 #b repres5ts ! effect produc$ by plac+ x 9 contact ) a lay] ( s5sitive ,*loride & expos+ to light2 & fig4 #c is ! result ( copy+ ?is negative aga9 on ,*loride ( ,silv]4 ,fig4 #c !re=e is a ,positive copy ( ,fig4 #a1 obta9$ by means ( a ,negative4 ,by ! fir/ op]ation ! t9ts are rev]s$2 by ! second1 be+ rev]s$ aga91 !y are made to correspond to ! orig9al4 ,! possession ( a ,negative !re=e enables u to obta9 ,positive copies ( ! object1 indef9ite 9 numb] & all precisely simil> 9 appe>ance4 ,?is capability ( multiply+ impressions is ( ! utmo/ importance1 & has r5d]$ ! production ( good ,negative ,photographs ( great] consequ5ce ?an any o!r bran* ( ! ,art4 ,! same ,photograph may (t5 be made to %[ ei!r z a ,positive or z a ,negative4 ,= in/ance1 suppos+ a piece ( silv]-leaf to be cut into ! %ape ( a cross & pa/$ on a squ>e ( glass1 ! appe>ance pres5t$ by x w\ld v>y "u diff]5t circum/ances4 ,illu/ration3 ,fig4 #a4 ,fig4 #b4 ,fig4 #a repres5ts x plac$ on a lay] ( black velvet2 fig4 #b z held up to ! light4 ,if we t]m x ,positive 9 ! fir/ case1 i4 e4 by reflect$ light1 !n x is ,negative 9 ! second1 t is1 by transmitt$ light4 ,! explanation is obvi\s4 ,!re=e to c>ry our orig9al def9ition ( ,positives & ,negatives a little fur!r1 we may say1 t ! =m] are usually view$ by reflect$1 & ! latt] by transmitt$1 light4 ,all ,photographs h[ev] _c be made to repres5t bo? ,positives & ,negatives4 ,9 ord] to possess ?is capability1 x is necess>y t a "p ( ! image %\ld be transp>5t1 & ! o!r opaque b ) a bright surface4 ,^! conditions are fulfill$ :5 ! ,iodide ( ,silv] ^u ,collodion is employ$1 9 conjunction ) a develop+ ag5t4 ,e ,collodion picture is to a c]ta9 ext5t bo? ,negative & ,positive1 & h5ce ! processes = obta9+ bo? v>ieties ( ,photographs are sub/antially ! same4 ,al?\gh h[ev] ! g5]al *>act]s ( a ,positive & a ,negative are simil>1 !re are "s po9ts ( diff]5ce4 ,a surface :i* appe>s p]fectly opaque :5 look$ d[n ^u1 becomes some:at transluc5t on be+ held up to ! light2 h5ce1 to give ! same effect1 ! deposit ( metal 9 a ,negative mu/ be proportionally ?ick] ?an 9 a positive2 o!rwise ! m9or details ( ! image1 w be invisible1 f n ob/ruct+ ! light suffici5tly4 ,) ^! prelim9>y rem>ks1 we are prep>$ to inve/igate m closely ! rationale ( ! processes = obta9+ ,collodion ,positives & ,negatives4 ,all t ref]s to pap] ,positives ^u ,*loride ( ,silv] w be treat$ 9 a subsequ5t ,*apt]4 ,,section ,i4 ,on ,collodion ,positives4 ,collodion ,positives are sometimes t]m$ direct1 because obta9$ by a s+le op]ation4 ,! ,*loride ( ,silv]1 act$ ^u by light alone1 is n adapt$ to yield direct ,positives1 ! r$uc$ surface be+ d>k & incapable ( repres5t+ ! lights ( a picture4 ,h5ce a develop+ ag5t is necess>ily employ$1 & ! ,iodide ( ,silv] sub/itut$ = ! ,*loride1 z be+ a m s5sitive prep>ation4 ,collodion ,positives are closely alli$ 9 _! nature to ,dagu]reotypes4 ,! diff]5ce betwe5 ! two consi/s pr9cipally 9 ! surface us$ to su/a9 ! s5sitive lay]1 & ! nature ( ! sub/ance by :i* ! invisible image is develop$4 ,9 a ,collodion ,positive ! lights are =m$ by a bright surface ( r$uc$ ,silv]1 & ! %ad[s by a black backgr\nd %[+ ?r\gh ! transp>5t portions ( ! plate4 ,two ma9 po9ts are to be att5d$ to 9 ! production ( ^! ,photographs4 ,fir/1 to obta9 an image di/9ct 9 e "p1 b ( comp>atively small int5sity4--,if ! deposit ( r$uc$ metal be too ?ick1 ! d>k backgr\nd is n se5 to a suffici5t ext5t1 & ! picture 9 consequ5ce is defici5t 9 %ad[4 ,secondly1 to :it5 ! surface ( ! r$uc$ metal z mu* z possible1 9 ord] to produce a suffici5t contra/ ( light & %ade4 ,iodide ( ,silv] develop$ 9 ! usual way pres5ts a dull yell[ appe>ance :i* is sombre & unpleas+4 ,! ,collodion & ,nitrate ,ba? = ,positives4--,good ,positives may be obta9$ by dilut+ d[n a sample ( ,collodion ) ,e!r & ,alcohol until x gives a pale blui% film 9 ! ,ba?4 ,! proportion ( ,iodide ( ,silv] be+ 9 t case small1 ! action ( ! high lights is less viol5t1 & ! %ad[s are all[$ m "t to impress !mselves4 ,! dilution less5s ! am\nt ( ,pyroxyl9e 9 ! ,collodion at ! same "t ) ! ,iodide1 :i* is an advantage1 ! slight & transp>5t films always giv+ m %>pness & def9ition 9 ! picture4 ,! employm5t ( a v ?9 film = ,positives is n h[ev] always a successful process4 ,! p>ticles ( ! ,iodide ( ,silv] be+ closely 9 contact ) ! glass1 unusual c>e is requir$ 9 clean+ ! plates 9 ord] to avoid /a9s2 & ! am\nt ( free ,nitrate ( ,silv] reta9$ ^u ! surface ( ! film be+ small1 circul> pat*es ( imp]fect developm5t are liable to occur1 unless ! r$uc+ ag5t be scatt]$ ev5ly & p]fectly ov] ! surface4 ,also if free ,iod9e or organic sub/ances :i* h a ret>d+ effect on ! action ( light are pres5t to a consid]able ext5t1 ! ,collodion w n "w well ) a small proportion ( ,iodide4 ,! ,au?or f\nd 9 exp]im5t+ on ?is subject t ) p]fectly pure ,collodion & a neutral ,ba? mo/ vigor\s impressions 7 produc$ :5 ! d5sity ( ! film _h be5 s f> r$uc$ by dilution t sc>cely any?+ c\ld be se5 ^u ! glass2 b ) ,collodion /rongly t9t$ ) ,iod9e1 or ) a ,ba? conta9+ ,nitric ,acid1 x 0 necess>y to /op ! dilution at a c]ta9 po9t or ! film became absolutely ins5sitive to feeble radiations ( light1 & ! %ad[s c\ld n be br\ght out by any am\nt ( exposure4 ,9 ?is case1 by add+ m ,iodide a bett] effect 0 obta9$4 ,a ?ick] ,collodion may be us$ = positives if a little free ,iod9e be add$1 = ! purpose ( dim9i%+ int5sity & keep+ ! %ad[s cle> dur+ ! developm5t4 ,?is process is easi] to practice ?an ! la/1 b does n always give ! same p]fect def9ition4 ,no organic sub/ance ( ! class to :i* ,glycyrrhiz9e & ,sug>s belong %\ld be add$ to ,collodion :i* is to be us$ = ,positives4 ,by s do+ ! image w\ld be r5d]$ int5se1 & ! high lights liable to sol>ization1 id e/1 a d>k appe>ance by reflect$ light4 ,! ,nitrate ,ba?4--,if ! mat]ials are pure1 ! ,nitrate ,ba? may advantage\sly be dilut$ d[n at ! same "t ) ! ,collodion1 :5 ,positives are to be tak52 b ! employm5t ( a v weak ,nitrate ,ba? 7su* z "o ( #bj gra9s to ! ounce71 al?\gh highly useful 9 obviat+ excess ( developm5t1 has "s disadvantages2 x becomes necess>y to exclude free ,nitric ,acid1 & to avoid ! employm5t ( a ,collodion too highly t9t$ ) ,iod9e4 ,on ! o!r h&1 ) a /rong ,nitrate ,ba?1 & a tol]ably d5se film ( ,iodide ( ,silv]1 a bett] result is (t5 secur$ by ! use ( ,nitric ,acid4 ,! s5sitiv5ess ( ! plates is impair$1 b at ! same "t ! int5sity is dim9i%$1 & ! picture %[s well ^u ! surface ( ! glass4 ,a new ,ba? is bett] = tak+ ,positives ?an "o :i* has be5 a long "t 9 use4 ,! latt] (t5 causes haz9ess & irregul> m>k+s on ! film dur+ ! action ( ! develop]4 ,?is is due p>tly to ! accumulation ( ,alcohol & ,e!r 9 ! ,ba?1 :i* causes ! solution ( ,sulphate ( ,iron to fl[ 9 an oily mann]2 & p>tly to a r$uction ( ! ,nitrate ( ,silv] by organic matt]4 ,! pres5ce ( ,acetate ( ,silv] is objectionable 9 a ,positive ,nitrate ,ba? z produc+ sol>ization & int5sity ( image2 h5ce ^? precautions :i* obviate its =mation mu/ be adopt$ 7p4 #hi74 ,if fus$ ,nitrate ( ,silv] be us$ = ! ,positive ,nitrate ,ba?1 x is v important t ! fusion %\ld n be c>ri$ too f>1 or ! solution w\ld conta9 a basic ,nitrite ( ,silv]1 & yield an int5se1 sol>iz$1 & mi/y image4 ,! ,develop]s = ,collodion ,positives4--,pyrogallic ,acid :5 us$ ) ,acetic ,acid1 z is usual = negative pictures1 produces a surface :i* is dull & yell[4 ,?is may be obviat$ by sub/itut+ ,nitric ,acid 9 small quantity = ! ,acetic4 ,! surface produc$ by ,pyrogallic ,acid ) ,nitric ,acid is lu/reless1 b v :ite1 if ! solution be us$ ( ! prop] /r5g?4 ,on attempt+ to increase ! am\nt ( ,nitric ,acid ! deposit becomes metallic1 & ! half-tones ( ! picture are injur$2 ,pyrogallic ,acid1 al?\gh an active develop]1 does n all[ ( ! addition ( m9]al acid to ! same ext5t z ! ,salts ( ,iron4 ,x requires also1 :5 comb9$ ) ,nitric ,acid1 a fair proportion ( ,nitrate ( ,silv] on ! film1 or ! developm5t w be imp]fect 9 p>ts ( ! plate4 ,sulphate ( ,iron4--,! ,protosalts ( ,iron 7 fir/ employ$ 9 ,photography by ,mr4 ,hunt4 ,! ,sulphate is a mo/ en]getic develop]1 & (t5 br+s out a picture :5 o!rs w\ld fail4 ,to produce by means ( x a dead :ite t9t ) abs5ce ( metallic lu/re1 x may be us$ 9 conjunction ) ,acetic ,acid1 & 9 a some:at conc5trat$ condition1 s z to develope ! picture quickly4 ,! addition ( ,nitric ,acid to ,sulphate ( ,iron modifies ! developm5t1 mak+ x m sl[ & gradual1 & produc+ a bright sp>kl+ surface ( r$uc$ ,silv]4 ,too mu* ( ?is acid h[ev] mu/ n be us$1 or ! action w be irregul>4 ,! ,nitrate ,ba? also mu/ be tol]ably conc5trat$1 9 ord] to comp5sate = ! ret>d+ effect ( ,nitric ,acid ^u ! developm5t4 ,! blue & transp>5t films ( ,iodide ( ,silv]1 =m$ 9 a v dilute ,nitrate ,ba?1 are n well adapt$ = ,positives to be develop$ 9 ?is way4 ,!y are injur$ by ! acid1 & ! developm5t ( ! image becomes imp]fect4 ,protonitrate ( ,iron4--,?is salt1 fir/ us$ by ,dr4 ,diamond1 is rem>kable z giv+ a surface ( brilliant metallic lu/re )\t any addition ( free acid4 ,!oretically1 x may be consid]$ z closely correspond+ to ! ,sulphate ( ,iron ) ,nitric ,acid add$4 ,!re are h[ev] slight practical diff]5ces betwe5 !m1 :i* are p]haps 9 fav\r ( ! ,protonitrate4 ,! r$uc+ p[]s ( ,protoxide ( ,iron appe> to be 9 inv]se ratio to ! /r5g? ( ! acid ) :i* x is associat$ 9 its salts2 h5ce ! ,nitrate is by f> ! mo/ feeble develop] ( ! ,protosalts ( ,iron4 ,! rules already giv5 = ! use ( ,sulphate ( ,iron acidifi$ ) ,nitric ,acid1 apply also to ! ,nitrate ( ,iron2 ! proportion ( free ,nitrate ( ,silv] mu/ be l>ge1 & ! film ( ,iodide ( ,silv] n too transp>5t4 ,9 develop+ direct ,positives ei!r by ,pyrogallic ,acid or ! ,salts ( ,iron1 ! col\r ( ! image w be f\nd liable to "s v>iation2 ! "* ( ! light1 :e!r bright or feeble1 & ! l5g? ( exposure 9 ! ,cam]a1 affect+ ! result4 ,a ,process = :it5+ ! ,positive ,image by means ( ,bi*loride ( ,m]cury4--,9 place ( bright5+ ! ,positive image by modify+ ! develop]1 x 0 propos$ "s "t s9ce by ,mr4 ,ar*] to effect ! same object by ! use ( ! salt kn[n z ,corrosive ,sublimate1 or ,bi*loride ( ,m]cury4 ,! image is fir/ develop$ 9 ! usual way1 fix$1 & wa%$4 ,x is !n treat$ ) ! solution ( ,bi*loride1 ! effect ( :i* is to produce almo/ imm$iately an int]e/+ s]ies ( *anges 9 col\r4 ,! surface fir/ d>k5s consid]ably1 until x becomes ( an a%-grey1 approa*+ to black2 %ortly x beg9s to get light]1 & assumes a pure :ite t9t1 or a :ite slightly incl9+ to blue4 ,x is !n se51 on exam9ation1 t ! :ole sub/ance ( ! deposit is entirely conv]t$ into ?is :ite p[d]4 ,! rationale ( ! reaction ( ,bi*loride ( ,m]cury appe>s to be1 t ! ,*lor9e ( ! m]curial salt divides itself betwe5 ! ,m]cury & ! ,silv]1 a portion ( x pass+ to ! latt] metal & conv]t+ x into a ,proto*loride4 ,! :ite p[d] is !re=e probably a comp\nd salt1 z is fur!r evid5c$ by ! effects produc$ on treat+ x ) v>i\s reag5ts4 ,,section ,,ii4 ,on ,collodion ,negatives4 ,z 9 ! case ( a direct ,positive we require an image :i* is feeble ?\gh di/9ct1 s1 on ! o!r h&1 = a negative1 x is necess>y to obta9 "o ( consid]able int5sity4 ,9 ! ,*apt] imm$iately foll[+ ! pres5t1 x w be %[n t 9 us+ glass ,negatives to produce ,positive copies ^u ,*loride ( ,silv] pap]1 a good result _c be secur$ unless ! ,negative is suffici5tly d>k to ob/ruct light /rongly4 ,! ,collodion & ,nitrate ,ba? = ,negatives4--,a ,collodion conta9+ a v small portion ( ,iodide & yield+ a blue transp>5t film 9 ! ,ba? is n well adapt$ = tak+ ,negatives4 ,pale opalesc5t films (t5 give too little int5sity 9 ! high lights1 &1 unless ! ,nitrate ,ba? be acid1 d n admit ( be+ expos$ 9 ! ,cam]a = ! prop] l5g? ( "t )\t cl\d9ess & indi/9ctness ( image be+ produc$ "u ! action ( ! develop]4 ,! effect kn[n z sol>ization ( negatives1 i4 e4 a r$ & transluc5t appe>ance ( ! highe/ lights1 is also m liable to occur :5 op]at+ ) a v pale film4 ,on ! o!r h&1 if ! lay] ( ,iodide be too yell[ & creamy1 ! half-tones ( ! image w (t5 be imp]fectly develop$1 s t a middle po9t betwe5 ^! extremes is ! be/4 ,a pure & newly prep>$ ,collodion1 al?\gh highly s5sitive to light1 does n always give1 ) "o application ( ! develop]1 a suffici5tly vigor\s image to s]ve z a negative matrix2 & ?is p>ticul>ly 9 ! mo/ brightly illum9at$ p>ts1 su* z ! sky 9 a l&scape photograph1 or ! :ite bord]s ( an engrav+4 ,b on keep+ ! ,collodion = "s weeks or mon?s x becomes yell[1 if iodiz$ ) ! alkal9e iodides1 & a decomposition takes place 9 x1 z be=e %[n 7p4 #ig71 :i* less5s ! rapidity ( action1 b adds to ! int5sity ( ! negative4 ,grape ,sug> may be employ$ = ! purpose ( giv+ int5sity to newly mix$ ,collodion3 also ,glycyrrhiz9e1 :i* is a res9\s body extract$ f ! root ( ,liquorice2 b z bo? sub/ances h an effect 9 less5+ ! s5sitiv5ess & keep+ qualities ( ! fluid1 !y %\ld be us$ cauti\sly4 ,9 tak+ portraits 9 ! op5 air1 on bright days1 & ) a ,ba? :i* has be5 mix$ = a consid]able "t1 x w r>ely be f\nd t ! int5sity w be defici5t2 & especially s if ! develop] be appli$ a second "t to ! film ) a few drops ( solution ( ,nitrate ( ,silv] add$4 ,9 l&scape ,photography h[ev]1 or 9 copy+ engrav+s1 :]e extreme s5sitiv5ess is n an object1 ! ,glycyrrhiz9e may sometimes be add$ ) advantage 9 ord] to obta9 p]fect opacity ( ! blacks4 ,:5 ! use ( ?is sub/ance is resort$ to1 ! mode ( iodiz+ ! ,collodion appe>s to be ( importance1 ! increase ( int5sity be+ great] ) ! ,iodide ( ,cadmium ?an ) ! ,iodides ( ! ,alkalies2 ! latt] probably ex]cis+ a decompos+ action4 ,an addition ( a ,bromide or a ,*loride to ! ,collodion 9 small quantity has also a m>k$ effect 9 add+ to ! int5sity :5 ,glycyrrhiz9e is us$ ) alkal9e ,iodides 7p4 #aja74 ,sub/ances :i* produce int5sity ( ! ,collodion image h (t51 if add$ 9 too l>ge quantity1 a t5d5cy to l[] ! half-tone1 & prev5t ! d>k] p>ts ( ! picture f be+ suffici5tly br\ght out4 ,! pr9t f ! ,negative is !n pale & :ite1 or *alky z x is t]m$1 9 ! high lights4 ,collodion 9 ?is condition is (t5 pref]r$ by ! beg9n]1 f ! facility ) :i* ! ,negatives are obta9$1 b x does n give ! f9e/ results4 ,an excess ( ,glycyrrhiz9e 9 ,collodion has also ! effect ( int]f]+ ) ! precipitation ( ! ,iodide ( ,silv]1 produc+ a blue & smoky film :i* is ne>ly useless = ,negatives4 ,a judici\s employm5t ( free ,iod9e 9 ,collodion :i* has be5 previ\sly int5sifi$ ) ,glycyrrhiz9e1 has a rem>kable effect 9 improv+ ! gradation ( tone4 ,! excessive opacity ( ! high lights is dim9i%$1 & h5ce ! op]ator is enabl$ by a long] exposure ( ! s5sitive plate to br+ out ! %ad[s & m9or details ( ! image ) great di/9ctness4 ,collodion prep>$ 9 ?is mann] is too sl[ to be us$ = portraits1 except+ 9 a /rong light1 b (t5 gives an image ) great r\ndness & /]eoscopic effect4 ,! ,iod9e & ! liquorice sug> employ$ conjo9tly1 t5d also to pres]ve ! cle>ness ( ! plates "u ! influ5ce ( ! develop]1 & to give %>pness to ! l9es & dots ( engrav+s1 etc41 :i*1 ) a new & s5sitive ,collodion1 are (t5 imp]fectly r5d]$4 ,^! advantages w be appreciat$ by ! op]ator :o has fail$ f work+ ) a too feeble ,collodion2 b x mu/ be borne 9 m9d1 t all sub/ances act+ z int5sifi]s h a bad effect :5 ! /ate ( ! film is n su* z to call = _! employm5t4 ,! ,proto-iodide ( ,iron has be5 recomm5d$ z an addition to ,negative ,collodion4 ,9 ! ,nitrate ,ba? x =ms1 9 addition to ,iodide ( ,silv]1 ,protonitrate ( ,iron1 an un/able sub/ance & a develop]4 ,! use ( ,iodide ( ,iron gives great s5sibility1 b x is difficult to pres]ve x pure & un*ang$4 ,x also decomposes ! ,collodion 9 ! c\rse ( a few h\rs1 becom+ itself p]oxidiz$1 & produc+ an ins5sitive condition ( film4 ,9 addition to ?is1 ! negatives tak5 by ! aid ( ,iodide ( ,iron are commonly ( an inf]ior k9d1 ! r$uction be+ too m>k$ 9 ! high lights2 s t its employm5t is ( d\btful utility4 ,! ,nitrate ,ba?4--,?is %\ld be prep>$ f ,nitrate ( ,silv] :i* has be5 melt$ at a mod]ate heat 7see pp4 #ac & #aja74 ,if ?is po9t be neglect$1 ! be/ ,collodion w sometimes fail 9 produc+ an int5se negative4 ,acetic ,acid mu/ be add$ 9 m9ute quantity1 to pres]ve ! solution f a too ready r$uction by ! ,alcohol & ,e!r ( ! ,collodion4 ,also1 unless ! ,nitrate ( ,silv] be q pure & free f organic matt] 7p4 #ajd71 cle> pictures w n be obta9$ )\t ! use ( ,acid4 ,acetate ( ,silv] has (t5 be5 advis$ z an addition to ! ,negative ,nitrate ,ba?4 ,x is produc$ by dropp+ into ! solution an alkali1 su* z ,ammonia1 foll[$ by ,acetic ,acid 9 excess4 ,! ,negatives are r5d]$ black] & m vigor\s by ?is proce$+1 b especially s :5 ! ,ba? is contam9at$ ) ,nitric ,acid2 :i* neutralizes itself at ! exp5se ( ! ,acetate ( ,silv]1 ?us3-- ,acetate ( ,silv] ,nitric ,acid ,nitrate ( ,silv] ,acetic ,acid4 ,z a rule1 x w be bett] to avoid add+ ,acetate ( ,silv] to ! ,ba?1 s9ce )1 pure melt$ ,nitrate ( ,silv] no ,nitric ,acid c be pres5t1 & p]fect int5sity is easily obta9$4 ,:5 ! ,ba? is saturat$ ) ,acetate ( ,silv]1 x is 9 a m r$ucible /ate1 & h5ce unless ! glass plates are v p]fectly clean$1 black l9es & m>k+s1 ! results ( irregul> action1 w be produc$ on ! application ( ! develop] to ! film 7p4 #ajd74 ,sol>ization1 or r$d5+ by ov]-exposure1 is also promot$ by ! pres5ce ( ,acetate ( ,silv]4 ,develop+ solutions = ,negatives4--,! ,protosalts ( ,iron are n usually employ$ 9 develop+ ,negative impressions4 ,!y are liable to yield a violet-col\r$ image1 :i* _c easily be r5d]$ m int5se by cont9u+ ! action4 ,gallic ,acid is too feeble = develop+ ,collodion pictures4 ,pyrogallic ,acid is mu* sup]ior1 & may be us$ ( any /r5g?1 accord+ to ! effect desir$4 ,:5 ! light is bad1 ! temp]ature l[1 & ! ,negative developes sl[ly & appe>s blue & inky by transmitt$ light1 ! proportion ( ! r$uc+ ag5t %\ld be increas$4 ,b ) an int5se ,collodion1 on a cle> summ]'s day1 ! f9e/ gradation is obta9$ ) a weak solution1 :i* does n beg9 to act until ! plate has be5 ev5ly cov]$4 ,a /rong develop] might 9 su*1 a case produce too mu* opacity 9 ! highe/ lights1 & w\ld probably occasion /a9s ( irregul> r$uction4 ,modes ( /r5g!n+ a f9i%$ impression :i* is too feeble to be us$ z a ,negative4--,! ord9>y plan ( pu%+ ! developm5t _c be appli$ ) advantage aft] ! picture has be5 wa%$ & dri$4 ,9 t case1 if x is f\nd to be too feeble to pr9t well1 its int5sity may be increas$ by "o ( ! foll[+ me?ods4-- ,x mu/ be premis$ h[ev]1 t ! same degree ( excell5ce is n to be expect$ 9 a ,negative ,photograph :i* has be5 improp]ly develop$ 9 ! fir/ in/ance & m especially if ! exposure to light 0 too %ort4 ,any in/antane\s ,positive may be r5d]$ suffici5tly int5se = a ,negative1 b 9 t case ! %ad[s are almo/ inv>iably imp]fect4 #a4 ,treatm5t ( ! image ) ,sulphurett$ ,hydrog5 or ,hydrosulphate ( ,ammonia4--,! object is to conv]t ! metallic ,silv] into ,sulphuret ( ,silv]1 & if ?is c\ld be done x w\ld be ( s]vice4 ,! m]e application ( an ,alkal9e ,sulphuret has h[ev] b little effect ^u ! image1 except+ to d>k5 its surface & de/roy ! ,positive appe>ance by reflect$ light2 ! /ructure ( ! metallic deposit be+ too d5se to admit ( ! ,sulphur rea*+ its int]ior4 ,pr(essor ,donny 7',photographic ,j\rnal1' vol4 i47 proposes to obviate ?is by fir/ conv]t+ ! image into ! :ite ,salt ( ,m]cury & ,silv] by ! application ( ,bi*loride ( ,m]cury1 & aft]w>ds treat+ x ) solution ( ,sulphurett$ ,hydrog5 or ,hydrosulphate ( ,ammonia4 ,negatives produc$ 9 ?is way are ( a br[n-yell[ col\r by transmitt$ light1 & opaque to *emical rays to an ext5t :i* w\ld n1 priori1 h be5 anticipat$4 #b4 ,,mm4 ,b>reswil & ,davanne's process4--,! image is conv]t$ into ,iodide ( ,silv] by treat+ x ) a saturat$ solution ( ,iod9e 9 wat]4 ,x is !n wa%$--to remove ! excess ( ,iod9e1--expos$ to ! light1 & a portion ( ! ord9>y develop+ solution1 mix$ ) ,nitrate ( ,silv]1 p\r$ ov] x4 ,! *anges :i* ensue are precisely ! same z ^? already describ$2 ! :ole object ( ! process be+ to br+ ! metallic surface back aga9 into ! condition ( ,iodide ( ,silv] modifi$ by light1 t ! develop+ action may be comm5c$ afre%1 & m ,silv] deposit$ f ! ,nitrate 9 ! usual way4 #c4 ,! process ) ,bi*loride ( ,m]cury & ,ammonia4--,! image is fir/ conv]t$ into ! usual :ite d\ble ,salt ( ,m]cury & ,silv] by ! application ( a solution ( ! ,corrosive ,sublimate4 ,x is !n treat$ ) ,ammonia1 ! effect ( :i* is to black5 x int5sely4 ,probably ! alkali acts by conv]t+ ,*loride ( ,m]cury into ! black ,oxide ( ,m]cury4 ,9 place ( ,ammonia1 a dilute solution ( ,hyposulphite ( ,soda or ,cyanide ( ,potassium may be us$1 ) v simil> results4 ,,*apt] ,,viii4 ,,on ,,! ,,!ory ,,( ,,positive ,,pr9t+4 ,! subject ( ,collodion ,negatives hav+ be5 expla9$ 9 ! previ\s ,*apt]1 we proce$ to %[ h[ !y may be made to yield an indef9ite numb] ( copies ) ! lights & %ad[s correct z 9 nature4 ,su* copies are t]m$ ,positives1 or sometimes ,positive pr9ts1 to di/+ui% !m f direct ,positives ^u ,collodion4 ,!re are two di/9ct modes ( obta9+ photographic pr9ts2--fir/ by developm5t1 or1 z x is t]m$1 by ! ,negative process1 9 :i* a lay] ( ,iodide or ,*loride ( ,silv] is employ$1 & ! invisible image develop$ by ,gallic ,acid2 & second1 by ! direct action ( light ^u a surface ( ,*loride ( ,silv]1 no develop] be+ us$4 ,^! processes1 involv+ *emical *anges ( great delicacy1 require a c>eful explanation4 ,! action ( light ^u ,*loride ( ,silv] 0 describ$ 9 ,*apt] ,,ii4 ,x 0 %[n t a gradual process ( d>k5+ took place1 ! comp\nd be+ r$uc$ to ! condition ( a col\r$ subsalt2 also1 t ! rapidity & p]fection ( ! *ange 7 increas$ by ! pres5ce ( excess ( ,nitrate ( ,silv]1 & ( organic matt]s1 su* z ,gelat9e1 ,album51 etc4 ,we h n[ to suppose t a s5sitive pap] has be5 prep>$ 9 ?is way1 & t a ,negative hav+ be5 laid 9 contact ) x1 ! comb9ation has be5 expos$ to ! ag5cy ( light = a suffici5t l5g? ( "t4 ,^u remov+ ! glass1 a ,positive repres5tation ( ! object w be f\nd bel[1 ( great beauty & detail4 ,n[ if ?is image 7 9 its nature fix$ & p]man5t1 or if !re 7 means ( mak+ x s1 )\t injury to ! t9t1 ! production ( ,pap] ,positives w\ld c]ta9ly be a simple dep>tm5t ( ! ,photographic ,art2 = x w be f\nd t ) almo/ any ,negative1 & ) s5sitive pap] h[ev] prep>$1 ! picture w look tol]ably well on its fir/ removal f ! pr9t+-frame4 ,imm]sion 9 ! ba? ( ,hyposulphite ( ,soda h[ev]1 :i* is ess5tially necess>y 9 ord] to fix ! picture1 produces an unfav\rable effect ^u ! t9t2 decompos+ ! violet-col\r$ ,sub*loride ( ,silv]1 & leav+ beh9d a r$ sub/ance :i* appe>s to be unit$ to ! fibre ( ! pap]1 &1 :5 te/$1 reacts 9 ! mann] ( a ,suboxide ( ,silv]4 ,o!r *emical op]ations are !re=e requir$ to remove ! objectionable r$ col\r ( ! pr9t1 & h5ce ! consid]ation ( ! subject is naturally divid$ into two p>ts2 fir/1 ! means by :i* ! pap] is r5d]$ s5sitive1 & ! image impress$ ^u x2--& secondly1 ! subsequ5t fix+ & ton+1 z x may be t]m$1 ( ! pro(4 ,! pres5t ,*apt] w also include1 9 two additional ,sections1 a cond5s$ acc\nt ( ! mo/ important facts relat+ to ! prop]ties & ! mode ( pres]vation ( photographic pr9ts4 ,,section ,i4 ,! ,prep>ation ( ! ,s5sitive ,pap]4 ,9 ?is ,section ! g5]al !ory ( ! prep>ation ( ,positive pap]1 9 s f> z x affects ! tone & int5sity ( ! pr9t1 w be describ$2 ! read] be+ ref]r$ to ! second division ( ! ,"w = ! =mul requir$4 ,! ,prep>ation ( ! ,s5sitive ,pap]4--,! conditions :i* are requir$ = produc+ a %>p & well def9$ pr9t are--t an ev5 lay] ( ,*loride ( ,silv] %\ld exi/ ^u ! v surface ( ! pap]1 & t ! p>ticles ( ?is ,*loride %\ld be 9 contact ) a suffici5t excess ( ,nitrate ( ,silv]4 ,^! po9ts h be5 already ref]r$ to at an e>ly "p ( ! ,"w 7p4 #ai74 ,! mat]ial us$ = siz+ ! pap] is ( importance4 ,engli% pap]s are usually siz$ ) ,gelat9e1 :i* is a photographic ag5t1 & acts *emically 9 =m+ ! image4 ,=eign pap]s on ! o!r h& be+ siz$ ) />* only1 require an addition ( ,gelat9e1 ,case9e1 or ,album51 to reta9 ! ,salt at ! surface ( ! pap]1 & to assi/ 9 produc+ ! picture3 if o!rwise1 ! pr9t w be flat & mealy1 z x is t]m$4 ,album5 especially produces a beautifully smoo? surface1 & is advantage\sly employ$ 9 pr9t+ small portraits & /]eoscopic subjects4 ,! uni=m surface di/ribution ( ! ,*loride ( ,silv] is sometimes int]f]$ ) by a faulty /ructure ( ! pap]1 caus+ x to absorb liquids unev5ly1 & 9 consequ5ce ! pictures1 :5 remov$ f ! pr9t+ frame1 appe> spott$4 ,ano!r cause produc+ ! same effect1 is ! employm5t ( too weak a solution ( ,nitrate ( ,silv]1 or ! removal ( ! %eet f ! ,nitrate ba? be=e ! ,*loride ( ,ammonium has be5 p]fectly decompos$2 x is ?us r5d]$ unequally s5sitive at diff]5t portions ( ! surface1 & ! pr9ts h ! *>act]i/ic m>bl$ appe>ance above ref]r$ to4 ,a suffici5t excess ( ,nitrate ( ,silv] be+ ess5tial1 x is important to be> 9 m9d1 t ! quantity ( ?is salt ev5tually rema9+ 9 ! pap]1 is mu* influ5c$ by ! mann] 9 :i* ! solution is appli$4 ,if x be laid on by float+1 !n ! proportion ( ,nitrate to t ( ,*loride ( ,sodium %\ld be ab\t z #c to #a 7! atomic weights are ne>ly z #e to #b72 b if ! plan ( bru%+ or spread+ ) a glass rod be adopt$1 #g to #a or #h to #a w n be too mu*4 ,! ,d>k5+ ( ! ,s5sitive ,pap] by ,light4--,! op]ator %\ld be famili> ) ! *anges ( col\r :i* indicate ! progress ( ! r$uction ( ! s5sitive lay]4 ,mu* 9 ?is respect dep5ds ^u ! k9d ( organic matt] us$1 b !re is always a regul> sequ5ce ( t9ts2 9 ! case ( a pap] prep>$ simply ) ,*loride ( ,ammonium & ,nitrate ( ,silv]1 x is z foll[s3 pale violet1 violet-blue1 slate-blue1 bronze or copp]-col\r4 ,:5 ! bronz$ /age is rea*$1 !re is no fur!r *ange4 ,on imm]sion 9 ! fix+ ba? ( ,hyposulphite1 ! violet tones due to ,sub*loride ( ,silv] are de/roy$1 & ! pr9t assumes a r$ or br[n col\r1 :i* is deepe/ & mo/ int5se 9 ! p>ts :]e ! light has act$ longe/4 ,h5ce we see1 t1 to produce a good pr9t1 x is ess5tial t ! ,negative %\ld possess consid]able int5sity 9 ! d>k p>ts4 ,pale & feeble ,negatives yield pro(s :i* are want+ 9 vig\r1 & h a flat & indi/9ct appe>ance4 ,! comb9ation _c be expos$ to light = a suffici5t l5g? ( "t to br+ ab\t ! requisite degree ( r$uction ( ! ,*loride ( ,silv]2 & h5ce ! deepe/ %ad[s ( ! result+ ,positive are n suffici5tly d>k1 & !re is a want ( contra/ :i* is fatal to ! effect4 ,a good ,negative %\ld be s opaque z to pres]ve ! lights ( ! pr9t$ image b5ea? cle>1 until ! d>ke/ %ades are ab\t to pass into ! bronze or copp]y condition4 ,if ! am\nt ( int5sity be less ?an ?is1 ! f9e/ effect _c be obta9$4 ,,conditions ,,affect+ ,,! ,,s5sitiv5ess ,,( ,,! ,,pap] ,,& ,,! ,,int5sity ,,( ,,! ,,image4 ,"s ( ! pr9cipal ( ^! are z foll[s3-- a4 ,! ,/r5g? ( ! ,salt+ ,ba?4--,! s5sibility ( ! pap] is regulat$ up to a c]ta9 po9t by ! am\nt ( salt#af us$ 9 ! prep>ation4 ,! quantity ( alkal9e ,*loride det]m9es ! am\nt ( ,*loride ( ,silv]2 & ) a prop] excess ( ,nitrate ( ,silv]1 pap]s are to a c]ta9 po9t m s5sitive 9 proportion z !y conta9 m ( ! ,*loride4 #af ,! diff]5ce 9 ! atomic weights ( ! v>i\s soluble ,*lorides us$ 9 salt+ mu/ be borne 9 m9d4 ,t5 gra9s ( ,*loride ( ,ammonium conta9 z mu* ,*lor9e z elev5 ( ,*loride ( ,sodium1 or tw5ty-two gra9s ( ,*loride ( ,b>ium4 7,see ! ,vocabul>y1 ,"p ,,iii47 ,highly s5sitiz$ pap]s d>k5 rapidly1 & pass v completely into ! bronze /age4 ,^? conta9+ less ,*loride d>k5 m sl[ly1 & d n become bronz$ ) ! same int5sity ( light4 ,a ,photographic pr9t1 =m$ ^u pap] highly salt$ & s5sitiz$1 is usually vigor\s1 ) great contra/ ( light & %ade2 p>ticul>ly s :5 ! pr9t+ is conduct$ 9 a /rong light4 ,h5ce x w be an advantage1 ) a feeble ,negative1 & 9 dull wea!r1 to d\ble ! ord9>y quantity ( ,salt1 :]eas 9 ! case ( an int5se ,negative1 & ) direct sunlight1 ! deep %ad[s w be too mu* bronz$ unless ! quantity ( ,*loride & ,nitrate ( ,silv] 9 ! pap] be kept l[4 ,9 proportion z ,photographic pap]s are highly salt$ & s5sitiz$1 !y become m prone to *ange col\r spontane\sly 9 ! d>k4 b4 ,proportion ( ,nitrate ( ,silv]4--,! comp\nd on :i* a positive pr9t is =m$ is a ,*loride1 or an organic ,salt ( ,silv]1 ) an excess ( ,nitrate ( ,silv]4 ,no?+ is ga9$ by increas+ ! proportion ( ,*loride ( ,sodium1 unless at ! same "t an addition be made to ! quantity ( free ,nitrate 9 ! s5sitiz+ ,ba?4 ,a surface ( ,*loride ( ,silv] ) a b>e excess ( ,nitrate1 d>k5s on exposure1 b x does n rea* ! bronz$ /age2 ! action appe>+ to /op at a c]ta9 po9t4 ,on plac+ ! pr9t 9 ,hyposulphite ( ,soda1 x becomes v r$ & pale1 & :5 t9t$1 looks cold & slaty1 )\t dep? or int5sity4 c4 ,! s5sitiv5ess & int5sity affect$ by sub/itut+ ! ,oxide ( ,silv] = ! ,nitrate4--,_m op]ators employ a solution ( ,oxide ( ,silv] 9 ,ammonia#ag or ,nitrate ( ,ammonia1 9 prep>+ ,*loride ( ,silv] pap]4 ,by do+ s1 a great increase ( s5sitiv5ess1 & also ( int5sity ( image1 is obta9$4 ,?is w be und]/ood if we rememb] t ! action ( light 9 produc+ ! pr9t is ( a r$uc+ nature4 ,h5ce ! sub/itution ( ,oxide = ,nitrate ( ,silv] facilitates ! decomposition2 j z ,ammonio-,nitrate ( ,silv] is m readily r$uc$ by ,gallic or ,pyrogallic ,acid ?an ! simple ,nitrate 7see p4 #ca74 #ag ,! *emi/ry ( ,ammonio-,nitrate ( ,silv] is expla9$ 9 ! ,vocabul>y1 ,"p ,,iii4 ,ammonio-,nitrate pap] has ! disadvantage ( soon discol\r+ :5 kept2 b x is v s]viceable 9 pr9t+ dur+ ! w9t] mon?s4 ,! proportion ( ,*loride 9 ! salt+ ,ba? may1 if desir$1 be consid]ably r$uc$2 ! int5sity ( action be+ greatly exalt$ by ! use ( ! ,oxide ( ,silv]4 d4 ,employm5t ( organic matt]s4--,^? recomm5d$ 9 ?is "w are--,album51 ,gelat9e1 & ,icel& ,moss4 ,album5 adds mu* to ! s5sibility ( ! pap]1 & gives v f9e surface def9ition4 ,a less am\nt ( ,*loride is requir$ ?an 9 ! case ( pla9 pap] simply salt$1 ! glut9\s "* ( ,album9\s liquids caus+ m ( ! fluid to be reta9$ ^u ! surface ( ! pap]1 & ! animal matt] assi/+ ! r$uction4 ,by v>y+ ! proportion ( salt1 bo? feeble & int5se ,negatives may be pr9t$ successfully ^u album9iz$ pap]4 ,no process gives bett] results1 ei!r z reg>ds s5sitiv5ess1 or 9 fai?fully r5d]+ all ! f9] details ( ! ,negative1 ?an ! process ) ,album54 ,icel& ,moss1 :5 boil$ 9 wat]1 yields a mucilag9\s liquid :i* is conv5i5tly employ$ z a vehicle = ,*loride ( ,silv]2 x increases ! s5sitiv5ess ( ! pap] & gives additional p[] ( bronz+1 by assi/+ to r$uce ! free ,nitrate ( ,silv]4 ,_m o!r organic matt]s1 t5d+ to absorb oxyg51 w\ld act 9 ! same way4 ,gelat9e is us$ 9 positive pr9t+2 x is analog\s to ,album5 9 composition1 &1 l x1 =ms a r$ comp\nd ) ,suboxide ( ,silv]4 ,x is s]viceable 9 keep+ ! pr9t at ! surface ( ! pap]1 b does n alt] ! s5sibility or ! g5]al appe>ance ( ! f9i%$ picture s greatly z ,album54 e4 ,impurities 9 ,nitrate ( ,silv]4--,nitrate ( ,silv] us$ = ,photographic pr9t+ %\ld be free f ev5 a trace ( ,protonitrate ( ,m]cury1 s9ce x is kn[n t ! precipitation ( ,*loride ( ,m]cury prev5ts ! d>k5+ ( ,*loride ( ,silv] by light4 ,! peculi> condition ( ,nitrate ( ,silv] spok5 ( at page #aja1 9 :i* x is ?\ght to conta9 ,oxides ( ,nitrog51 is likely to int]f]e ) ,photographic pr9t+4 ,?is is probably ! explanation ( a faulty /ate ( ! ,nitrate solution1 9 :i* x yields r$ & feeble positives1 & does n d>k5 9 col\r 9 excit+ album9iz$ pap]4 ,! rem$y w be1 to fuse ! ,nitrate ( ,silv] at a mod]ate heat be=e dissolv+ x4 ,,! ,,col\r ,,( ,,! ,,image ,,influ5c$ ,,by ,,! ,,prep>ation ,,( ,,! ,,s5sitive ,,pap]4 ,?is subject %\ld be /udi$ by ^? :o desire to pr9t ) ta/e4 ,by introduc+ a few simple modifications into ! mode ( prep>+ ! s5sitive pap]1 almo/ any v>iety ( t9t may be obta9$4 ,! t5d5cy ( ! ton+ process1 to :i* ! pr9t is aft]w>ds to be submitt$1 is to d>k5 ! col\r1 &1 if gold be us$1 to give a %ade ( blue4 ,h5ce1 if ! ,positive be pr9t$ ( a r$ tone1 x w *ange 9 ! gold ,ba? to a purple2 :]eas if left1 aft] exposure to light & fix+1 ( a d>k br[n or sepia t9t1 x passes by ton+ into a pure black4 ,! ,positive %\ld look w>m & bright on its removal f ! pr9t+ frame2 b ! t9t :i* rema9s aft] imm]sion 9 ,hyposulphite ( ,soda is ! prop] col\r ( ! simply fix$ pr9t4 ,! foll[+ po9ts may be m5tion$ z affect+ ! col\r & g5]al appe>ance ( ! picture4 a4 ,! proportions ( ,salt & ,nitrate ( ,silv]4--,highly salt$ & s5sitiz$ pap]s give a d>k] image ?an ^? :i*1 conta9+ a small proportion ( ,*loride ( ,silv]1 are less s5sitive to light4 ,h5ce 9 pr9t+ ^u pap] weakly s5sitiz$1 9 ord] to br+ out ! f9] details ( a highly int5se negative1 we f9d ! image unusually r$ aft] fix+1 & ( a br[n or mulb]ry col\r :5 ton$4 ,! above rem>ks apply also 9 "s degree to ! /r5g? ( ! ,nitrate ,ba?1 & especially s :5 no organic matt] except+ ,gelat9e is employ$1--9 su* a case ! image w be d>k] aft] fix+1 if ! proportion ( free ,nitrate ( ,silv] be l>ge4 b4 ,effect ( ,oxide ( ,silv] on ! col\r4--,pr9ts =m$ ^u ,ammonio-,nitrate pap]s highly salt$ are ( a sepia col\r aft] fix+1 & usually ( a pure black or a purple-black :5 ton$4 ,) ! increas$ facility ( r$uction by light af=d$ by use ( ,oxide ( ,silv]1 !re is also less r$ness 9 ! pr9t4 ,b if ! quantity ( salt us$ 9 prep>+ ! pap] be r$uc$ to a m9imum 7"o gra9 to ! ounce or less71 = ! sake ( economy or to improve ! half-tone1 !n ! usual r$ col\r returns1 & ! ,positive is br[n or purple aft] ton+1 9 place ( black4 ,?us by employ+ a solution ( ,oxide ( ,silv]1 ! op]ator is enabl$1 )\t ! addition ( organic matt]1 to pr9t ,positives ( a pleas+ v>iety ( t9t1 comb9$ ) a peculi> s(tness & delicacy1 :i* _c easily be obta9$ ) ! simple ,nitrate ( ,silv]4 c4 ,! col\r affect$ by organic matt]4--,album5 is coagulat$ by ,nitrate ( ,silv]1 & =ms a p]man5t gloss ^u ! pap]4 ,! s5sitive album9iz$ pap] d>k5s 9 ! sun to a *ocolate-br[n col\r1 :i* becomes v r$ on imm]sion 9 ! ,hyposulphite4 ,! f9i%$ pr9ts are cle> & transp>5t2 usually ( a br[n tone1 or ) a %ade ( purple :5 ! gold ,ba? is newly made & active2 pure blacks are n easily obta9$4 ,icel& ,moss affects ! col\r ( ! pro( to a c]ta9 ext5t1 b less ?an ,album52 ! f9i%$ pr9ts are ne>ly black if ! pap] is highly salt$4 ,! ,gelat9\s siz+ us$ = ! ,engli% pap]s1 & obta9$ by boil+ hides 9 wat]1 & h>d5+ ! product by an admixture ( ,alum1 has a r$d5+ influ5ce ^u r$uc$ ,silv] salts1 analog\s to t ( ,album51 or ( ,case9e1 ! *>act]i/ic animal pr9ciple ( milk4 ,positives pr9t$ ^u ,engli% pap]1 commonly assume "s %ade ( br[n m or less remov$ f black2 ! d>k] tones be+ m readily obta9$ ^u ! =eign pap]s4 ,citrates & ,t>trates h a m>k$ effect ^u ! col\r ( pr9ts4 ,pap] prep>$ ) ,citrate1 9 addition to ,*loride ( ,silv]1 d>k5s to a f9e purple col\r :i* *anges to brick-r$ 9 ! fix+ ,ba?4 ,! ,positives1 :5 ton$1 are usually ( a violet-purple or ( a bi/re t9t1 ) a g5]al aspect ( w>m? & transp>5cy4 ,,section ,,ii4 ,! ,processes = ,fix+ & ,ton+ ! ,pro(4 ,?is "p ( ! op]ation is "o to :i* great att5tion %\ld be paid1 9 ord] to secure bright & la/+ col\rs3 x involves m ( delicate *emical *ange ?an p]haps any o!r dep>tm5t ( ! ,art4 ,! fir/ po9t requir+ explanation is ! process ( fix+2 to :i* 7p4 #da7 brief ref]5ce has already be5 made4 ,! me?ods adopt$ to improve ! t9t ( ! f9i%$ picture w !n be describ$4 ,,conditions ,,( ,a ,,prop] ,,fix+ ,,( ,,! ,,pro(4 ,?is subject is n always und]/ood by op]ators1 & consequ5tly !y h no c]ta9 guide z to h[ long ! pr9ts %\ld rema9 9 ! fix+ ,ba?4 ,! "t occupi$ 9 fix+ w ( c\rse v>y ) ! /r5g? ( ! solution employ$2 b !re are simple rules :i* may be usefully foll[$4 ,9 ! act ( dissolv+ ! unalt]$ ,*loride ( ,silv] 9 ! pro(1 ! fix+ solution ( ,hyposulphite ( ,soda conv]ts x into ,hyposulphite ( ,silv] 7p4 #dc71 :i* is soluble 9 an excess ( ,hyposulphite ( ,soda4 ,b if !re be an insuffici5t excess1--t is1 if ! ,ba? be too weak1 or ! pr9t remov$ f x too spe$ily1--!n ! ,hyposulphite ( ,silv] is n p]fectly dissolv$1 & beg9s by degrees to decompose1 produc+ a br[n deposit 9 ! tissue ( ! pap]4 ,?is deposit1 :i* has ! appe>ance ( yell[ spots & pat*es1 is n usually se5 ^u ! surface ( ! pr9t1 b becomes v evid5t :5 x is held up to ! light1 or if x be split 9 half1 :i* c be readily done by glu+ x betwe5 two flat surfaces ( deal1 & !n =c+ !m asund]4 ,! reaction ( ,hyposulphite ( ,soda ) ,nitrate ( ,silv]4--,9 ord] to und]/& m fully h[ decomposition ( ,hyposulphite ( ,silv] may affect ! process ( fix+1 ! peculi> prop]ties ( ?is salt %\ld be /udi$4 ,) ?is view ,nitrate ( ,silv] & ,hyposulphite ( ,soda may be mix$ 9 equival5t proportions1 viz4 ab\t tw5ty-"o gra9s ( ! =m] salt to sixte5 gra9s ( ! latt]1 fir/ dissolv+ ea* 9 sep>ate vessels 9 half an ounce ( di/ill$ wat]4 ,^! solutions are to be add$ to ea* o!r & well agitat$2 imm$iately a d5se deposit =ms1 :i* is ,hyposulphite ( ,silv]4 ,at ?is po9t a curi\s s]ies ( *anges comm5ces4 ,! precipitate1 at fir/ :ite & curdy1 soon alt]s 9 col\r3 x becomes can>y-yell[1 !n ( a ri* orange-yell[1 aft]w>ds liv]-col\r1 & f9ally black4 ,! rationale ( ^! *anges is expla9$ to a c]ta9 ext5t by /udy+ ! composition ( ! ,hyposulphite ( ,silv]4 ,! =mula = ?is sub/ance is z foll[s3-- ,ag,o ,s#b,o#b4 ,b ,ag,o ,s#b,o#b pla9ly equals ,ag,s1 or ,sulphuret ( ,silv]1 & ,,s#c1 or ,sulphuric ,acid4 ,! acid reaction assum$ by ! sup]natant liquid is due !re=e to ,sulphuric ,acid1 & ! black sub/ance =m$ is ,sulphuret ( ,silv]4 ,! yell[ & orange-yell[ comp\nds are e>li] /ages ( ! decomposition1 b _! exact nature is unc]ta94 ,! in/ability ( ,hyposulphite ( ,silv] is pr9cipally se5 :5 x is 9 an isolat$ /ate3 ! pres5ce ( an excess ( ,hyposulphite ( ,soda r5d]s x m p]man5t1 by =m+ a d\ble salt1 z already describ$4 ,9 fix+ ,photographic pr9ts1 ?is br[n deposit ( ,sulphuret ( ,silv] is v liable to =m 9 ! ,ba? & ^u ! picture2 p>ticul>ly s :5 ! temp]ature is high4 ,to obviate x1 obs]ve ! foll[+ directions3--,x is especially 9 ! reaction betwe5 ,nitrate ( ,silv] & ,hyposulphite ( ,soda t ! black5+ is se52 ! ,*loride & o!r insoluble ,salts ( ,silv] be+ dissolv$1 ev5 to saturation1 )\t any decomposition ( ! ,hyposulphite =m$4 ,h5ce if ! pr9t be wa%$ 9 wat] to remove ! soluble ,nitrate1 a v mu* weak] fix+ ,ba? ?an usual may be employ$4 ,b if ! pro(s are tak5 at once f ! pr9t+ frame & imm]s$ 9 a dilute ,ba? ( ,hyposulphite 7"o "p ( ! salt to six or eight ( wat]71 a %ade ( br[n may (t5 be obs]v$ to pass ov] ! surface ( ! pr9t1 & a l>ge deposit ( ,sulphuret ( ,silv] soon =ms z ! result ( ! decomposition4 ,on ! o!r h&1 ) a /rong ,hyposulphite ,ba? !re is little or no discoloration1 & ! black deposit is abs5t4 ,! pr9t mu/ also be left = a suffici5t "t 9 ! fix+ ba?1 or "s appe>ance ( br[n pat*es1#ah visible by transmitt$ light1 may occur4 ,ea* atom ( ,nitrate ( ,silv] requires ?ree atoms ( ,hyposulphite ( ,soda to =m ! sweet & soluble d\ble salt1 & h5ce1 if ! action be n cont9u$ suffici5tly long1 ano!r comp\nd w be =m$ almo/ ta/eless & insoluble 7p4 #dd74 ,ev5 imm]sion 9 a new ,ba? ( ,hyposulphite ( ,soda does n fix ! pr9t :5 once ! yell[ /age ( decomposition has be5 e/abli%$4 ,?is yell[ salt is insoluble 9 ,hyposulphite ( ,soda1 & consequ5tly rema9s 9 ! pap]4 #ah ,! writ] has notic$ t :5 s5sitive pap] is kept = "s "t be=e be+ us$ = pr9t+1 ^! yell[ pat*es ( imp]fect fixation are v liable to occur4 ,! ,nitrate ( ,silv] appe>s gradually to ent] into comb9ation ) ! organic matt] ( ! size ( ! pap]1 & _c !n be s easily extract$ by ! fix+ ba?4 ,9 fix+ pr9ts by ,ammonia ! ,au?or has f\nd t ! same rule may be appli$ z 9 ! case ( ,hyposulphite ( ,soda1 viz4 t if ! process be n prop]ly p]=m$1 ! :ite p>ts ( ! pr9t w appe> spott$ :5 held up to ! light1 f a portion ( insoluble ,silv] ,salt rema9+ 9 ! pap]4 ,pr9ts imp]fectly fix$ by ,ammonia are also usually br[n & discol\r$ ^u ! surface ( ! pap]4 ,m exact directions z to ! /r5g? ( ! fix+ ba? & ! "t occupi$ 9 ! process1 w be giv5 9 ! ,second ,"p ( ! ,"w2 at pres5t x may be notic$ only t ,album9iz$ pap]1 f ! horny nature ( its surface-coat+1 requires a long] treatm5t ) ! ,hyposulphite ?an ! pla9 pap]4 ,,! ,,salts ,,( ,,gold ,,z ,,ton+ ,,ag5ts ,,= ,,photographic ,,pr9ts4 ,! ,salts ( ,gold h be5 successfully appli$ to ! improvem5t ( ! tones obta9$ by simply fix+ ! pro( 9 ,hyposulphite ( ,soda4 ,! foll[+ are ! pr9cipal modes foll[$3-- ,m4 ,le ,grey's ,process4--,! pr9t1 hav+ be5 expos$ to light until x becomes v mu* d>k] ?an x is int5d$ to rema91 is wa%$ 9 wat] to remove ! excess ( ,nitrate ( ,silv]4 ,x is !n imm]s$ 9 a dilute solution ( ,*loride ( ,gold1 acidifi$ by ,hydro*loric ,acid4 ,! effect is to r$uce ! int5sity consid]ably1 & at ! same "t to *ange ! d>k %ades to a violet or blui% t9t4 ,aft] a second wa%+ ) wat]1 ! pro( is plac$ 9 pla9 ,hyposulphite ( ,soda1 :i* fixes x & alt]s ! tone to a pure black or a blue-black1 accord+ to ! mann] ( prep>+ ! pap] & ! "t ( exposure to light4 ,! rationale ( ! process appe>s to be z foll[s3-- ! ,*lor9e1 previ\sly comb9$ ) ,gold1 passes to ! r$uc$ ,silv] ,salt2 x blea*es ! lighte/ %ades1 by conv]t+ !m aga9 into :ite ,proto*loride ( ,silv]1 & gives to ! o!rs a violet t9t m or less int5se accord+ to ! r$uction4 ,at ! same "t metallic ,gold is deposit$1 ! effect ( :i* is n visible at ?is /age1 s9ce ! same violet t9t is p]ceiv$ :5 a solution ( ,*lor9e is sub/itut$ = ,*loride ( ,gold4 ,! ,hyposulphite ( ,soda subsequ5tly employ$1 decomposes ! violet ,sub*loride ( ,silv]1 & leaves ! surface ( a black t9t1 due to ! ,gold & ! r$uc$ ,silv] ,salt4 ,m4 ,le ,grey's process is objectionable on acc\nt ( ! excessive ov]-pr9t+ requir$4 ,?is h[ev] is to a great ext5t obviat$ by a modification ( ! process 9 :i* an alkal9e in/ead ( an acid solution ( ! ,*loride is employ$2 "o gra9 ( ,*loride ( ,gold is dissolv$ 9 ab\t six ounces ( wat]1 to :i* are add$ tw5ty to ?irty gra9s ( ! common ,c>bonate ( ,soda4 ,! alkali mod]ates ! viol5ce ( ! action1 s t ! pr9t wa%$ ) wat] & imm]s$ 9 ! ,gold ,ba?1 is less r$uc$ 9 int5sity1 & does n acquire ! same inky blu5ess4 ,on subsequ5t fix+ 9 ! ,hyposulphite1 ! t9t *anges f violet to a d>k *ocolate-br[n1 :i* is p]man5t4 ,! ,tetra?ionate & ,hyposulphite ( ,gold employ$ 9 ton+4--,aft] ! discov]y ( ,le ,grey's mode1 x 0 propos$1 z an improvem5t1 to add ,*loride ( ,gold to ! fix+ solution1 s z to obviate ! necessity ( us+ two ,ba?s4 ,! pr9t1 9 t case1 al?\gh d>k5$ consid]ably1 is less r$uc$ 9 int5sity1 & ! same am\nt ( ov]-pr9t+ is n requir$4 ,! *emical *anges :i* ensue are diff]5t f be=e3 !y may be describ$ z foll[s3-- ,*loride ( ,gold1 add$ to ,hyposulphite ( ,soda1 is conv]t$ into ,hyposulphite ( ,gold1 ,tetra?ionate ( ,gold1 & 7if ! ,*loride ( ,gold be free f excess ( acid7 a r$ comp\nd1 conta9+ m ( ! metal ?an1 ei!r ( ! o!rs1 b ! exact nature ( :i* is unc]ta94 ,ea* ( ^! ?ree ,gold ,salts possesses ! prop]ty ( d>k5+ ! pr9t1 b n to ! same ext5t4 ,! activity is less z ! /ability ( ! salt is great]1 & h5ce ! r$ comp\nd1 :i* is s highly un/able t x _c be pres]v$ _m h\rs )\t decompos+ & precipitat+ metallic ,gold1 is f> m active ?an ! ,hyposulphite ( ,gold1 :i*1 :5 associat$ ) an excess ( ,hyposulphite ( ,soda1 is comp>atively p]man5t4 ,:5 rapidity ( col\r+ is an object x w !re=e be advisable to add ,*loride ( ,gold to ! fix+ ,ba? ( ,hyposulphite r ?an an equival5t quantity ( ,sel d'or2 & by dropp+ a little ,ammonia into ! ,*loride ( ,gold s z to precipitate fulm9at+ gold#ai 7a comp\nd :i* dissolves 9 ,hyposulphite ( ,soda ) consid]able =mation ( ! un/able r$ salt71 ! activity ( ! ,ba? w be promot$4 #ai ,read ! obs]vations on ! ,explosive ,prop]ties ( ,fulm9at+ ,gold 9 ! ,vocabul>y1 ,"p ,,iii4 ,! ,au?or expla9s ! action ( ^! ,salts ( ,gold ^u ! ,positive pr9t z foll[s3--!y are un/able1 & conta9 an excess ( ,sulphur loosely comb9$2 h5ce1 :5 plac$ 9 contact ) ! image1 :i* has an aff9ity = ,sulphur1 ! exi/+ comp\nd is brok5 up1 & ,sulphuret ( ,silv]1 ,sulphuric ,acid1 & metallic ,gold are ! results4 ,t a m9ute proportion ( ,sulphuret ( ,silv] is =m$ seems c]ta92 b ! *ange mu/ be sup]ficial1 z ! /ability ( ! pr9t is v little less5$ :5 ! process is prop]ly p]=m$4 ,sel ,or employ$ z a ton+ ag5t4--,?is process1 :i* 0 communicat$ to ! ',photographic ,j\rnal' by ,mr4 ,sutton ( ,j]sey1 has be5 f\nd s]viceable4 ,! pr9ts are fir/ wa%$ 9 wat]1 to :i* is add$ a little ,*loride ( ,sodium1 to decompose ! free ,nitrate ( ,silv]4 ,!y are !n imm]s$ 9 a dilute solution ( ,sel d'or1 or d\ble ,hyposulphite ( ,gold & ,soda1 :i* quickly *anges ! t9t f r$ to purple )\t de/roy+ any ( ! details or light] %ades4 ,la/ly1 ! ,hyposulphite ( ,soda is employ$ to fix ! pr9t 9 ! usual way4 ,?is process diff]s !oretically f ! la/ 9 "s important p>ticul>s4 ,! ton+ solution is appli$ to ! pr9t be=e fix+1 :i* exp]i5ce proves to h an important influ5ce ^u ! result1 x hav+ be5 f\nd t :5 ! pr9t is previ\sly act$ ^u by ,hyposulphite ( ,soda1 ! rapidity ( deposition ( ! ,gold is int]f]$ )2--?us1 a dilute solution ( ,sel d'or col\rs a pr9t rapidly1 b if to ?is same liquid a few cry/als ( ,hyposulphite ( ,soda be add$1 ! picture becomes r$ & may be kept 9 ! ,ba? = comp>atively a long "t )\t acquir+ ! purple tones4 ,z ,hyposulphite ( ,soda 9 excess less5s ! action ( ! ,sel d'or1 s on ! o!r h& ! addition ( an acid increases x4 ,! acid does n precipitate ,sulphur1 z might be expect$ f a k ( ! reaction ( ,hyposulphite ) acid bodies 7p4 #acg71 b x fav\rs ! r$uction ( metallic ,gold4 ,h5ce x is usual to add a little ,hydro*loric ,acid to ! ton+ solution ( ,sel d'or1 to increase ! rapidity & p]fection ( ! col\r+ process4 ,,! ,,conditions ,,:i* ,,affect ,,! ,,action ,,( ,,! ,,fix+ ,,& ,,ton+ ,,ba? ,,( ,,gold ,,& ,,hyposulphite ,,( ,,soda4 ,al?\gh ! process ( ton+ ,positives by ,sel d'or is v c]ta9 9 its results & gives good t9ts1 yet1 z involv+ a some:at great] exp5diture ( "t & tr\ble1 x is n at pres5t univ]sally adopt$4 ,! ord9>y plan ( fix+ & ton+ 9 "o ba? has be5 prov$ to yield p]man5t pr9ts if ! prop] precautions are obs]v$1 b x is q necess>y1 9 ord] to ensure success1 t ! conditions by :i* its action is modifi$ %\ld be und]/ood4 ,! m important ( ^! are z foll[s3-- a4 ,! ,,age ( ! ,ba?4--,:5 ,*loride ( ,gold is add$ to ,hyposulphite ( ,soda1 sev]al un/able salts are produc$1 :i* decompose by keep+4 ,h5ce ! solution is v active dur+ ! fir/ few days aft] mix+2 b at ! expiration ( "s weeks or mon?s1 if n us$1 x becomes almo/ in]t1 a r$di% deposit ( ,gold fir/ =m+1 & ev5tually a mixture ( black ,sulphuret ( ,silv] & ,sulphur1 ! =m] ( :i* (t5 adh]es to ! sides ( ! bottle 9 d5se %9+ lam94 ,:5 ! ,ba? is con/antly kept 9 use !re is a loss ( ,gold1 :i*1 al?\gh x is less p]ceiv$ ?an x o!rwise w\ld be1 f ! fact t sulphurett+ pr9ciples are =m$ 7see next page7 capable ( replac+ ! ,gold z ton+ ag5ts--yet makes ! ,ba? "w m sl[ly1 & h5ce ov]-pr9t+ is requir$4 b4 ,pres5ce ( free ,nitrate ( ,silv] ^u ! surface ( ! pro(4--,?is produces an accel]at+ effect1 z may be %[n by soak+ ! pr9t 9 salt & wat]1 to conv]t ! ,nitrate into ,*loride ( ,silv]2 ! action !n takes place m sl[ly4 ,! free ,nitrate ( ,silv] increases ! in/ability ( ! ,gold salts2 b if pres5t 9 too great an excess1 x is apt to cause a decomposition ( ,hyposulphite ( ,silv]1 & consequ5t yell[ness 9 ! :ite p>ts ( ! pro(4 ,x is !re=e p>ticul>ly recomm5d$ to wa% ! pr9t 9 wat] be=e imm]s+ x 9 ! fix+ & ton+ ,ba?4 c4 ,temp]ature ( ! solution4--,9 cold wea!r1 ! !rmomet] /&+ at #cb to #dj1 ! ,ba? works m sl[ly ?an usual2 :]eas 9 ! height ( summ]1 & especially 9 hot climates1 x occasionally becomes q unmanageable4 ,! be/ temp]ature = op]at+ successfully appe>s to be ab\t #fj to #fe ,fahr5heit2 if high] ?an ?is ! solutions mu/ be employ$ m dilute4 d4 ,addition ( ,iodide ( ,silv]4--,"s op]ators associate ,iodide ) ,*loride 9 ! prep>ation ( s5sitive pap] = pr9t+4 ,ano!r s\rce ( ! same salts is ! admixture ( a portion ( ! fix+ ,ba? us$ = ,negatives ) ! ,positive ton+ solution4 ,! pres5ce ( ,iodides 9 ! fix+ & ton+ ,ba? is injuri\s3 :5 9 l>ge excess1 !y dissolve ! image1 or produce yell[ pat*es ( ,iodide ( ,silv] on ! lights2 9 small] quantity1 ! deposition ( ! ,gold is h9d]$1 & ! action proce$s m sl[ly4 ,bromides & ,*lorides h n ! same effect4 e4 ,mode ( prep>+ ! pap]4--,! rapidity ( ton+ v>ies ) causes indep5d5t ( ! ,ba?3 ?us1 pla9 pap] pr9ts are ton$ m quickly ?an pr9ts ^u album9iz$ pap]1 & ! use ( ,engli% pap] siz$ ) ,gelat9e ret>ds ! action4 ,=eign pap]s r5d]$ s5sitive ) ,ammonio-,nitrate tone ! mo/ quickly4 ,on c]ta9 /ates ( ! fix+ & ton+ ,ba? :i* are injuri\s to ! pro(s4--,! object ( us+ ! ,hyposulphite ,ba? is to fix ! pro( & to tone x by means ( ,gold4 ,b x is a fact famili> to ! photographic *emi/1 t ,positives c also be ton$ by a sulphurett+ action1 & t ! col\rs s obta9$ are n v diff]5t f ^? :i* foll[ ! employm5t ( ,gold4#bj ,n[ ! ,hyposulphite ( ,soda is a sub/ance :i* c be v readily made to yield up ,sulphur to any bodies :i* possess an aff9ity = t elem5t1 & z ! r$uc$ ,silv] comp\nd 9 ! pr9t has su* an aff9ity1 !re is always a t5d5cy to absorption ( ,sulphur :5 ! pro(s are imm]s$ 9 ! ,ba?4 ,consequ5tly 9 _m cases a sulphur ton+-process is set up1 & z ! picture is improv$ by x 9 appe>ance1 los+ its brick-r$ col\r & assum+ a purple %ade1 x 0 at fir/ adopt$ by ,photograph]s4 ,exp]i5ce h[ev] has %[n t col\rs bright5$ 9 ?is way are less p]man5t ?an o!rs1 & are liable to fade unless kept p]fectly dry4 ,h5ce ! process w be disc>d$ by all c>eful op]ators1 & ! object w be to avoid sulphuration z f> z possible4 ,?is c be done to a great ext5t1 &1 :5 ! ,ba? is prop]ly manag$1 ! pr9ts w be ton$ almo/ entirely by ,gold1 & w1 ) c>e1 be p]man5t4 #bj ,= a m detail$ acc\nt ( ! ton+ process by ,sulphur1 see ! ,?ird ,section ( ?is ,*apt]1 page #ade4 ,! in/ability ( sulphurett$ pr9ts is %[n 9 ! f\r? ,section4 ,"s ( ! conditions :i* facilitate a sulphurett+ action ^u ! pro( are z foll[s3-- a4 ,! addition ( an ,acid to ! ,ba?4--,x 0 at "o "t common to add a few drops ( ,acetic ,acid to ! fix+ ,ba? ( ,hyposulphite ( ,soda1 imm$iately be=e imm]s+ ! pro(s4 ,! ,ba? !n assumes an opalesc5t appe>ance 9 ! c\rse ( a few m9utes1 &1 :5 ?is milk9ess is p]ceptible1 ! pr9t beg9s to tone rapidly & becomes ne>ly black4 ,! *emical *anges produc$ 9 a ,hyposulphite ,ba? by addition ( acid1 may be expla9$ ?us3--,! acid fir/ displaces ! feeble ,hyposulphur\s acid f its comb9ation ) ,soda4 ,acetic ,acid ,hyposulphite ,soda4 ,acetate ,soda ,hyposulphur\s ,acid4 ,!n ! ,hyposulphur\s ,acid1 n be+ a /able sub/ance :5 isolat$1 beg9s spontane\sly to decompose1 & splits up into ,sulphur\s ,acid--:i* rema9s dissolv$ 9 ! liquid1 communicat+ ! *>act]i/ic od\r ( burn+ ,sulphur--& ,sulphur1 :i* sep>ates 9 a f9ely divid$ /ate & =ms a milky deposit4#ba #ba ,f ! ,vocabul>y1 ,"p ,,iii41 x w be se5 t comm]cial ,*loride ( ,gold usually conta9s free ,hydro*loric ,acid2 h5ce a consid]able deposit ( ,sulphur takes place on add+ x to ! ,hyposulphite solution1 & ! liquid mu/ n be us$ imm$iately4 ,obs]ve !re=e t free acids ( all k9ds mu/ be exclud$ f ! fix+ ,ba?1 or1 if inadv]t5tly add$1 ! liquid mu/ be set aside = "s h\rs until ! ,hyposulphur\s ,acid has decompos$1 &1 ! ,sulphur hav+ settl$ to ! bottom1 ! ,ba? has rega9$ its orig9al neutral condition4#bb #bb ,! *emical read] w und]/& ! decomposition ( free ,hyposulphur\s ,acid by ! foll[+ equation3--,s#b,o#b ,,s#b & ,s4 b4 ,decomposition ( ! ,ba? by con/ant use4--,x has long be5 kn[n t a solution ( ,hyposulphite ( ,soda und]goes a peculi> *ange 9 prop]ties :5 mu* us$ 9 fix+4 ,:5 fir/ prep>$ x leaves ! image ( a r$ tone1 ! *>act]i/ic col\r ( ! r$uc$ ,silv] ,salt1 b soon acquires ! prop]ty ( d>k5+ ?is r$ col\r by a subsequ5t communication ( ,sulphur4 ,h5ce a simple fix+ ,ba? becomes at la/ an active ton+ ba?1 )\t any addition ( ,gold4 ,?is *ange ( prop]ties w be f\nd m fully expla9$ 9 ! ab/ract ( ! ,au?or's rese>*es giv5 9 ! next ,section 7p4 #aef74 ,at pres5t we rem>k only t x is due pr9cipally to a reaction betwe5 ,nitrate ( ,silv] & ,hyposulphite ( ,soda1 att5d$ ) decomposition ( ,hyposulphite ( ,silv] 7p4 #acj72 & h5ce1 if ! pr9ts are wa%$ 9 wat] be=e imm]sion 9 ! ,ba?1 ! solution w be less quickly liable to *ange4 ,_m op]ators /ate t ! ton+ ,ba? hav+ at fir/ be5 prep>$ ) ,*loride ( ,gold1 no fur!r addition ( ?is sub/ance w be requir$4 ,?is no d\bt is correct1 b 9 su* case ! pro(s w at la/ be ton$ by ,sulphur m ?an by ,gold1 & w n possess ! same /ability2 ! ,ba? w also1 aft] long use1 be f\nd to acquire a di/9ct acid reaction to te/-pap]1 ! acidity be+ due to a peculi> pr9ciple g5]at$ by decompos+ ,hyposulphite ( ,silv]1 & :i* is %[n to h an injuri\s action ^u ! pr9t 7p4 #aeh74 ,to avoid ?is ! solution %\ld be kept neutral to te/-pap] by means ( a drop ( ,ammonia1 if requir$2 & :5 x beg9s to be exhau/$1 & does n tone 7quickly7 a pr9t f :i* ! free ,nitrate ( ,silv] has be5 remov$ by wa%+1 a fre% quantity ( ,*loride ( ,gold %\ld be add$4 c4 ,tetra?ionate 9 ! ,hyposulphite ,ba?4--,! ,au?or has %[n t ! ,tetra?ionates1 :i* are analog\s to ! ,hyposulphites1 h an active sulphurett+ action ^u ,positive pr9ts 7see ! pap]s 9 ! next ,section74 ,v f9e col\rs c be obta9$ 9 ?is way2 b ton+ by ,sulphur hav+ be5 prov$ to be wrong 9 pr9ciple1 ! =mul giv5 9 ! fir/ two editions ( ?is ,"w h be5 omitt$4#bc #bc ,! prep>ation ( a ton+ ba? by ,tetra?ionate1 )\t ,gold1 is describ$ 9 ! next ,section1 b x is n recomm5d$ = practical use4 ,! bodies :i* produce ,tetra?ionate :5 add$ to a solution ( ,hyposulphite ( ,soda1 & h5ce are inadmissible 9 ! ton+ process1 are z foll[s3--,free ,iod9e1 ,p]*loride ( ,iron1 ,*loride ( ,copp]1 ,acids ( all k9ds 79 ! latt] case ! acid fir/ produces ,sulphur\s ,acid1 & ! ,sulphur\s ,acid1 if pres5t 9 any quantity1 by react+ ^u ,hyposulphite ( ,soda1 =ms ,tetra?ionate & ,tri?ionate ( ,soda74 ,*loride ( ,gold also produces a mix$ ,tetra?ionate ( ,gold & ,soda :5 add$ to ! fix+ ,ba? 7p4 #acc72 b z ! quantity ( ,*loride us$ is small1 ! pr9ts are f> less sulphurett$ ?an 9 ! case ( ton+ ,ba?s prep>$ by ,tetra?ionate )\t ,gold4 ,,section ,,iii4 ,! ,au?or's ,rese>*es 9 ,photographic ,pr9t+4 ,hav+ be5 long engag$ 9 conduct+ exp]im5ts ^u ! composition & prop]ties ( ! r$uc$ mat]ial =m+ ! ,photographic image1 & especially ) a view ( det]m9+ ! exact conditions "u :i* ! picture may be consid]$ p]man5t1 ! ,au?or has ?\ght x advisable to give ! results ( ^! rese>*es 9 ! =m ( an ab/ract ( ! orig9al pap]s read at ! meet+s ( ! ,photographic ,society4 ,a previ\s p]usal ( ^! pap]s w put ! read] 9 possession ( ! pr9cipal facts ^u :i* are f\nd$ ! precautions advis$ 9 ! next ,section = ! pres]vation ( ,photographic pr9ts4 ,9 ord] to keep ! ,"w z ne>ly z possible )9 its orig9al limits1 & also = ! purpose ( di/+ui%+ ! pres5t ,section f ! o!rs1 z "o ref]r+ pr9cipally to sci5tific details1 ! type has be5 r$uc$ to ! size ( t us$ 9 ! ,app5dix4 ,,on ,,! ,,*emical ,,composition ,,( ,,! ,,photographic ,,image4 ,! det]m9ation ( ! *emical nature ( ! ,photographic image 9 its v>i\s =ms is a po9t ( mu* importance1 bo? z indicat+ ! conditions requir$ = ! pres]vation ( works ( art ( t class1 & also z a guide to ! exp]im5t] 9 select+ bodies likely to h an effect z *emical ag5ts 9 ,photography4 ,x has be5 /at$ by "s :o h giv5 att5tion to ! subject1 t ! image is =m$ 9 all cases ( pure metallic ,silv]1 & t any obs]vable v>iations 9 its col\r & prop]ties1 are due to a diff]5ce 9 ! molecul> arrangem5t ( ! p>ticles4 ,b ?is hypo!sis1 al?\gh involv+ mu* t is correct1 yet does n conta9 ! :ole tru?1 = x is evid5t t ! *emical prop]ties ( ! ,photographic image (t5 be> no resemblance to ^? ( a metal4 ,"o ,photograph may also diff] ess5tially f ano!r1 s t we are l$ to inf] ! exi/5ce ( two v>ieties1 ! fir/ ( :i* is less ( a metallic nature ?an ! second4 ,9 inve/igat+ ! subject1 ! pr9cipal po9t appe>$ to be to exam9e ! action ( light ^u ,*loride ( ,silv]1 & aft]w>ds to associate ! ,*loride ) organic matt] 9 ord] to imitate ! conditions "u :i* ,photographs are obta9$4 ,! foll[+ is an epitome ( ! conclusions arriv$ at3-- ,action ( ,light ^u ,*loride ( ,silv]4--,! process is accompani$ by a sep>ation ( ,*lor9e1 b its product is n a m]e mixture ( ,*loride ( ,silv] & ,metallic ,silv]2 if x 7 s1 we _c suppose t ! d>k5+ w\ld take place b5ea? ! surface ( ,nitric ,acid1 :i* x is f\nd to d4 ,a def9ite ,sub*loride ( ,silv] seems to be =m$1 ! mo/ important prop]ty ( :i* is its decomposition by fix+ ag5ts1 su* z ,ammonia1 & ,hyposulphite ( ,soda1 bo? ( :i* de/roy ! violet col\r1 dissolv+ out ,proto*loride ( ,silv]1 & leav+ a small quantity ( a grey residue ( metallic ,silv]4 ,inasmu* !re=e z all ,photographic pictures require fix+1 we may conclude t if !y c\ld be produc$ ^u pure & isolat$ ,*loride ( ,silv] 7:i* h[ev] is n ! case71 !y w\ld consi/ solely ( metallic ,silv]4 ,decomposition ( organic ,salts ( ,silv] by ,light4--,comp\nds ( ,oxide ( ,silv] ) organic bodies1 are z a rule d>k5$ by exposure to light1 b ! process does n always consi/ 9 a simple r$uction to ! metallic /ate4 ,?is ass]tion is prov$ by ! employm5t ( ! foll[+ te/s4 a4 ,m]cury4--,little or no amalgamation takes place on triturat+ ! d>k5$ salt ) ?is metal4 b4 ,ammonia & fix+ ag5ts4--,^! usually produce only a limit$ am\nt ( action4 ,?us1 ! ,album9ate ( ,protoxide ( ,silv] is p]fectly soluble 9 ,ammonia2 b aft] hav+ be5 r$d5$ by exposure to light1 x is little or n at all affect$4 c4 ,pota%4--,animal matt]s coagulat$ by ,nitrate ( ,silv]1 & r$uc$ by ! sun's rays1 are dissolv$ by boil+ ,pota%1 ! solution be+ cle> & ( a blood-r$ col\r4 ,metallic ,silv]1 x is presum$1 if pres5t1 w\ld rema9 insoluble4 d4 ,boil+ ,wat]4--,gelat9e treat$ ) ,nitrate ( ,silv] & expos$ to light1 loses its *>act]i/ic prop]ty ( dissolv+ 9 hot wat]4 ,?is exp]im5t is conclusive4 ,! above facts ju/ify u 9 suppos+ ! exi/5ce ( comb9ations ( organic matt] ) a l[ ,oxide ( ,silv]2 & analysis indicates fur!r t ! relative proportion ( ea* con/itu5t 9 ^! comp\nds may v>y4 ,= in/ance1 :5 ,citrate ( ,silv] is r$uc$ by light1 & act$ on ) ,ammonia1 a black p[d] rema9s1 :i* 0 f\nd to conta9 z mu* z #ie p] c5t1 real ,silv]2 b ,album9ate ( ,silv] treat$ 9 ! same way yields on analysis less ( metallic ,silv]1 & m volatile & c>bonace\s matt]4 ,! use ( ,ammonio-,nitrate ( ,silv] 9 prep>+ ! salt t5ds also to increase ! relative quantity ( metal left 9 ! comp\nd aft] r$uction & fix+4 ,! l5g? ( "t dur+ :i* ! light has act$1 has also a modify+ effect ( ! same k9d1--! product ( r$uction by a p[]ful light be+ m ne>ly 9 ! /ate ( metal1 & conta9+ less bo? ( ,oxyg5 & organic matt]4 ,action ( ,light ^u ,*loride ( ,silv] associat$ ) organic matt]4--,photographs =m$ on ,*loride ( ,silv] alone1 w\ld1 aft] fix+1 consi/ ( metallic ,silv]1 b su* a process c\ld n be c>ri$ out 9 practice4 ,! addition ( organic matt] is absolutely necess>y 9 ord] to increase ! s5sitiv5ess1 & to prev5t ! image f be+ dissolv$ 9 ! ,ba? ( ,hyposulphite ( ,soda4 ,! blue ,sub*loride ( ,silv] is decompos$ by fix+1 a v scanty proportion ( grey metallic ,silv] rema9+ insoluble2 b ! r$ comp\nd ( ,suboxide ( ,silv] ) organic matt] is almo/ unaffect$ by ,hyposulphite ( ,soda1 or ,ammonia4 ,! increase ( s5sitiv5ess & int5sity produc$ by ! use ( organic matt] is accompani$ also by a *ange 9 ! composition ( ! picture2 ! image los+ ! metallic "* :i* x possesses :5 =m$ on pure ,*loride ( ,silv]1 & resembl+ 9 e respect ! product ( ! action ( light ^u organic ,salts ( ,silv]4 ,!re are c]ta9 *>act]i/ic te/s :i* may usefully be employ$ 9 di/+ui%+ ! metallic image f :at may be t]m$ ! organic or non-metallic image4 ,"o ( ^! te/s is ,cyanide ( ,potassium4 ,an image =m$ ^u pure ,*loride ( ,silv]1 al?\gh pale & feeble1 may1 aft] fix+1 be imm]s$ ill dilute solution ( ,cyanide ( ,potassium )\t injury4 ,b a photograph on ,*loride ( ,silv] support$ by an organic basis1 is mu* act$ ^u by ,cyanide ( ,potassium1 quickly los+ its f9] details4 ,a second te/ is ! ,hydrosulphate ( ,ammonia4 ,if no organic matt] be employ$1 ! image becomes d>k] & m int5se by treatm5t ) a soluble ,sulphuret2 :il/ ! non-metallic image1 =m$ on an organic surface1 is quickly blea*$ & fad$4 ,! action ( ,sulphur ^u ! image is inde$ a mode ( det]m9+ ! real quantity ( ,silv] pres5t4 ,:5 exi/+ 9 a v f9ely divid$ lay]1 ,sulphuret ( ,silv] (t5 appe>s yell[2 b 9 a ?ick] lay] x is black4 ,h5ce ! col\r ( ! ,photograph1 aft] treatm5t ) ,sulphurett$ ,hydrog51 is an indication ( ! proportion ( metal pres5t1 & ! reason ( ! organic image becom+ s p]fectly fad$ is because x conta9s a m9imum ( ,silv] 9 relation to ! int5sity4 ,we see1 !re=e1 t ! addition ( organic matt] to ,*loride ( ,silv] does n s mu* increase ! actual quantity ( ,silv] r$uc$ by light1 z x adds to its opacity by associat+ o!r elem5ts ) ! ,silv]1 & altoge!r modify+ ! composition ( ! image4 ,! employm5t ( oxidiz+ ag5ts %[s also t 9 an ord9>y ,photographic process by ! direct action ( light1 o!r elem5ts besides ,silv] assi/ 9 =m+ ! image3 ! pictures be+ f\nd to be easily susceptible ( oxidation1 :]eas ! metallic image =m$ on pure ,*loride ( ,silv] resi/s oxidation4 ,composition ( develop$ images4--,by expos+ s5sitive lay]s ( ! ,iodide1 ! ,bromide1 & ! ,*loride ( ,silv] to ! light = a %ort "t only1 & subsequ5tly develop+ ) ,gallic ,acid1 ,pyrogallic ,acid1 & ! protosalts ( ,iron1 a v>iety ( images may be obta9$1 :i* diff] f ea* o!r mat]ially 9 e important p>ticul>1 & a comp>ison ( :i* assi/s ! det]m9ation ( ! disput$ po9t4 ,! appe>ance & prop]ties ( ! develop$ ,photograph are f\nd to v>y ) ! exi/5ce ( ! foll[+ conditions4 #a/4 ,! surface us$ to su/a9 ! s5sitive lay]4--,!re is a peculi>ity 9 ! image =m$ on ,collodion4 ,collodion conta9s ,pyroxyl9e1 a sub/ance :i* behaves t[>ds ! salts ( ,silv] 9 a mann] diff]5t f t ( mo/ organic bodies1 exhibit+ no t5d5cy to assi/ _! r$uction by light4 ,h5ce ,*loride ( ,silv] on ,collodion d>k5s f> m sl[ly ?an ! same salt ^u ,album51 & ! image1 aft] fix+1 is feeble & metallic4 ,iodide ( ,silv] on ,collodion1 expos$ & develop$1 gives usually a m metallic image1 ) less int5sity1 ?an ,iodide ( ,silv] ^u ,album51 or on pap] siz$ ) ,gelat9e4 ,by add+ to ! ,collodion a body :i* has an aff9ity = l[ oxides ( ,silv]1 su* = in/ance z ,glycyrrhiz9e1 ! opacity ( ! develop$ image is increas$4 #bnd4 ,! nature ( ! s5sitive salt4--,:5 ,iodide ( ,silv] is us$ to receive ! lat5t impression1 ! image aft] developm5t1 al?\gh lack+ int5sity ( col\r by reflect$ light1 is m ne>ly 9 ! condition ( metallic ,silv] ?an if ,bromide or ,*loride ( ,silv] be sub/itut$2 & ( ! ?ree salts1 ! ,*loride gives ! mo/ int5sity1 ) ! lea/ quantity ( metallic ,silv]4 ,?is rule applies especially :5 organic matt]s1 ,gelat9e1 ,glycyrrhiz9e1 etc41 are pres5t4 #crd4 ,! develop+ ag5t employ$4--,an organic develop+ ag5t l ,pyrogallic ,acid may be expect$ to produce a ,collodion image m int5se1 b less metallic1 ?an an inorganic develop]1 su* z ! ,protosulphate ( ,iron4 #d?4 ,! l5g? ( "t dur+ :i* ! light has act$4--,ov]-action ( ! light fav\rs ! production ( an image :i* is d>k by reflection & br[n or r$ by transmission1 correspond+ 9 ^! p>ticul>s to :at may be t]m$ ! non-metallic image conta9+ an oxide ( ,silv]4 #e?4 ,! /age ( ! developm5t4--,! r$ image fir/ =m$ on ! application ( ! develop] to a gelat9iz$ or album9iz$ surface ( ,iodide ( ,silv] is less metallic1 & m easily injur$ by de/ructive te/s1 ?an ! black image1 :i* is ! result ( prolong+ ! action4 ,develop$ photographs :i* are ( a bright r$ col\r aft] fix+1 correspond 9 prop]ties to images obta9$ by ! direct action ( light on pap] prep>$ ) ,*loride ( ,silv]1 m ne>ly ?an to ,collodion1 or ev5 to fully develop$ ,talbotype ,negatives4 ,to conclude ! ,pap]1 ! foll[+ may be (f]$ 9 ! way ( recapitulation3--,an image consi/+ ( metallic silv]1 z a rule1 reflects :ite light1 & %[s z a positive :5 laid on black velvet2 b a non-metallic organic image is d>k1 & repres5ts ! %ad[s ( a picture4 ,collodion positives develop$ ) protosalts ( ,iron are ne>ly or q metallic4 ,photographs on ,album5 or ,gelat9e less s ?an ^? on ,collodion4 ,develop$ ,photographs conta9 m ,silv] ?an o!rs1 if ! developm5t has be5 prolong$4 ,! half %ad[s ( ! image 9 a ,positive ,pr9t are especially liable to suff] "u injuri\s conditions1 s9ce !y conta9 ! ,silv] 9 a less p]fect /ate ( r$uction4#bd #bd ,! ,au?or omits1 9 ?is place1 all m5tion ( molecul> conditions affect+ int5sity1 inasmu* z at ! pres5t "t no?+ positive has be5 det]m9$ ) reg>d to !m4 ,x is h[ev] kn[n t 9 ! use ( ! protosalts ( ,iron z develop+ ag5ts1 ! appe>ance ( ! image is mu* influ5c$ by ! rapidity ) :i* ! r$uction is effect$--! p>ticles ( ,silv] be+ l>g] & m metallic :5 ! developm5t is conduct$ sl[ly4 ,! process ( electro-plat+ & o!r *emical op]ations ( a simil> k9d prove t ! physical prop]ties ( metals precipitat$ f solutions ( _! salts1 v>y greatly ) ! degree ( f95ess & arrangem5t ( _! p>ticles4 ,,on ,,! ,,v>i\s ,,ag5cies ,,de/ructive ,,to ,,photographic ,,pr9ts4 ,action ( ,sulphurett+ ,comp\nds ^u ,positive ,pr9ts4--,x 0 fir/ notic$ by ,mr4 ,t4 ,a4 ,malone1 t ! mo/ int5se ,photograph might be de/roy$ by act+ ^u x ) solution ( ,sulphurett$ ,hydrog5 or a soluble ,sulphuret1 = a suffici5t l5g? ( "t4 ,! *anges produc$ by a sulphurett+ comp\nd act+ ^u ! r$ image ( a simply fix$ pr9t are ^!3--! col\r is fir/ d>k5$1 & a degree ( brilliancy imp>t$ to x2 ?is is ! effect t]m$ ton+4 ,!n ! w>m t9t by degrees alt]s to a cold] %ade1 ! int5sity ( ! :ole image is less5$1 & ! half-tones turn yell[4 ,la/ly1 ! full %ad[s pass also f black to yell[1 & ! pr9t fades4 ,n[ 9 ?is peculi> reaction we notice ! foll[+ po9ts ( int]e/4 ,if at t p>ticul> /age at :i* ! pr9t has rea*$ its maximum ( blackness1 x be rais$ p>tially out ( ! liquid & all[$ to project into ! air1 ! "p s treat$ becomes yell[ be=e t :i* rema9s imm]s$4 ,aga91 if a pr9t ton$ by ,sulphur be plac$ 9 a pan ( wat] to wa%1 aft] ! lapse ( sev]al h\rs x is apt to assume a fad$ appe>ance 9 ! half-tones4 ,! full %ad[s1 9 :i* ! r$uc$ ,silv] salt is ?ick] & m abundant1 reta9 _! black col\r = a long] "t1 b if ! action ( ! sulphurett+ ,ba? be cont9u$1 e portion ( ! pr9t becomes yell[4 ,^! facts prove t ,oxyg5 has an influ5ce 9 accel]at+ ! de/ructive action ( ! ,sulphur comp\nds ^u ,positive pr9ts2 & ?is idea is borne out by ! results ( fur!r exp]im5ts1 = x is f\nd t moi/ ,sulphurett$ ,hydrog5 has little or no effect 9 d>k5+ ! col\r :5 e trace ( air is exclud$4 ,:5 pr9ts are wa%$ 9 wat] !y are expos$ to ! influ5ce ( ! dissolv$ air :i* wat] always conta9s1 & h5ce ! *ange f black to yell[ is produc$4#be #be ,fur!r rem>ks ^u ! action ( damp air ^u ,positives ton$ by ,sulphur are giv5 at p4 #aec4 ,!re are "s sub/ances :i* facilitate ! yell[ deg5]ation ( ,positives ton$ by ,sulphur1 a k ( :i* w be useful3 !y are--#a/1 p[]ful oxidiz]s1 su* z ,*lor9e1 ,p]manganate ( ,pota%1 & ,*romic ,acid2 ^!1 ev5 :5 highly dilut$1 act ) great rapidity3 #bnd1 bodies :i* dissolve ,oxide ( ,silv]1 z soluble ,cyanides1 ,hyposulphites1 ,ammonia2 also acids ( v>i\s k9ds1 & h5ce ! frequ5cy ( yell[ f+] impressions ^u old sulphurett$ pr9ts1 :i* are probably caus$ by a trace ( organic 7,lactic87 ,acid left by contact ) ! w>m h&4 ,x 0 at "o "t suppos$ t ! ,photograph 9 ! /age at :i* x appe>s black5$ by ,sulphur1 consi/$ ( ,sulphuret ( ,silv]1 & t ?is black ,sulphuret became yell[ by absorption ( ,oxyg5 & conv]sion into ,sulphate4 ,,mm4 ,davanne & ,gir>d1 :o exam9$ ! subject1 ?\ght t !re might be two isom]ic =ms ( ,sulphuret ( ,silv]1 a black & a yell[ =m2 ! =m] ( :i* pass+ gradually into ! latt] produc$ ! fad+ ( ! impression4 ,b nei!r ( ^! views are correct2 = x is prov$ by c>eful exp]im5t1 t ! ,sulphuret ( ,silv] is a highly /able comp\nd1 n prone to oxidize1 &1 fur!r1 t ! *ange ( col\r f black to yell[ has no ref]5ce to a modification ( ?is salt4 ,! tru? appe>s to be t ! image :il/ 9 ! black /age conta9s o!r elem5ts besides ,sulphur & ,silv]1 b :5 x has become yell[ by ! cont9u$ action ( ! sulphurett+ comp\nd1 x is !n a true ,sulphuret4 ,comp>ative p]man5ce ( ,photographs "u ! action ( ,sulphur4--,develop$ ,positives1 z a rule1 /& bett] ?an ^? pr9t$ by direct exposure to light2 b mu* dep5ds ^u ! nature ( ! negative process foll[$2 & h5ce no g5]al /atem5t c be made :i* w n be liable to _m exceptions4 ,! mode ( conduct+ ! developm5t mu/ n be ov]look$4 ,! pr9ts1 :i* become v r$ 9 ! ,hyposulphite fix+ ,ba? f ! action ( ! develop] hav+ be5 /opp$ at too e>ly a p]iod1 are (t5 sulphurett$ & de/roy$ ev5 m readily ?an a vigor\s sun-pr9t obta9$ by direct exposure to light4 ,a po9t ( ev5 great] importance is ! nature ( ! s5sitive surface :i* receives ! lat5t image4 ,x is ! pr9t develop$ ^u ,iodide ( ,silv] :i* especially resi/s sulphuration4 ,9 t case1 n only is ! prelim9>y ton+ effect ( ! ,sulphur m sl[ ?an usual1 b ! impression _c be made to fade by any cont9uance ( ! action4 ,x loses mu* ( its brilliancy1 & is r$uc$ 9 int5sity1 b x is n s completely de/roy$ z to be useless4 ,! reason ( ?is1 z %[n 9 ! la/ pap]1 dep5ds ^u ! fact t ! ,talbotype pro(s conta9 ! l>ge/ am\nt ( ,silv] 9 ! image4 ,! employm5t ( ,gold 9 ton+ does n r5d] an ord9>y sun-pr9t z p]man5t z a ,positive develop$ ^u ,iodide ( ,silv]4 ,! deep %ad[s ( ! picture are protect$ by ! ,gold1 b ! light] %ades n s p]fectly4 ,h5ce aft] ! ,sulphur has act$1 9 place ( ! univ]sal yell[ & fad$ aspect pres5t$ by ! simple unton$ pr9t1 ! ,positive fully ton$ by ,gold has black %ad[s ) yell[ half-tones4 ,!re=e1 :il/ recomm5d+ ! use ( ,gold z a ton+ ag5t1 x does n seem advisable to lay too mu* /ress ^u x z a pres]vative f ! de/ructive action ( ,sulphur4 ,exposure ( ,positive ,pr9ts to a ,sulphurett+ ,atmosph]e4--,9 te/+ ! action ( a solution ( ,sulphurett$ ,hydrog5 ^u pap] ,positives1 x did n appe> t ! conditions "u :i* ! pr9ts 7 plac$ bore a suffici5tly close resemblance to ! case ( ,positives expos$ to an atmosph]e contam9at$ ) m9ute traces ( ! gas2 & ?is m p>ticul>ly because x is kn[n t dry ,sulphurett$ ,hydrog5 has comp>atively little effect ^u ,photographic ,pr9ts4 ,! exp]im5ts 7 !re=e repeat$ 9 a some:at diff]5t =m4 ,a numb] ( ,positives 7ab\t ?ree doz57 pr9t$ 9 v>i\s ways1 7 susp5d$ 9 a glass case1 measur+ #b-a_/b feet by #ba in*es1 & conta9+ #g-a_/b cubic feet ( air2 into :i* 0 introduc$1 occasionally1 a few bubbles ( ,sulphurett$ ,hydrog51 j suffici5t to keep ! air ( ! *amb] smell+ p]ceptibly ( ! gas4 ,a poli%$ ,dagu]reotype plate 0 hung up 9 ! c5tre1 to s]ve z a guide to ! progress ( ! sulphurett+ action4 ,by ! second day ! metal plate _h acquir$ a fa9t yell[ hue1 n easily se5 except 9 c]ta9 positions2 b ! ,positives 7 unaffect$4 ,at ! expiration ( ?ree days ! majority ( ! pictures exhibit$ no signs ( *ange1 b a few unton$ pr9ts ( a pale r$ col\r1 "s ( :i* _h be5 pr9t$ by developm5t1 & o!rs by direct exposure to light1 _h p]ceptibly d>k5$4 ,aft] ! eigh? day1 ! action1 appe>+ to progress m sl[ly ?an at fir/1 0 /opp$1 & ! pr9ts remov$4 ,! g5]al results obta9$ 7 z foll[s3-- ,! ,dagu]reotype plate _h become /rongly t>ni%$ ) a film ( ,sulphuret ( ,silv]1 :i* appe>$ yell[i%-br[n 9 "s p>ts & /eel-blue 9 o!rs4 ,! ,positives 71 z a rule1 ton$ to a slightly cold] %ade1 b _m ( !m _h sc>cely *ang$4 ,no obvi\s diff]5ce 0 obs]v$ betwe5 pr9ts develop$ on pap] prep>$ ) ,*loride ( ,silv]1 & o!rs pr9t$ by direct exposure to light2 b 9 all cases ! pr9ts obta9$ by ^? me?ods :i* give a v r$ image aft] fix+1 7 ! fir/ to %[ ! *ange ( col\r due to sulphuration1 ! pro(s submitt$ to ! te/ hav+ all be5 previ\sly ton$ ) ,gold4 ,effect ( ,oxidiz+ ,ag5ts ^u ,positive ,pr9ts4--,x appe>$ ( importance to asc]ta9 to :at ext5t ,photographic ,pr9ts are susceptible ( oxidation2 on acc\nt ( ! atmosph]ic influ5ces to :i* !y are necess>ily expos$4 ,9 exp]im5t+ ^u ?is subject ! foll[+ results h be5 obta9$4 ,p[]ful oxidiz]s de/roy ,positive ,pr9ts rapidly2 ! action usually comm5c+ at ! corn]s & edges ( ! pap]1 or at any isolat$ po9t1 su* z a metallic speck or p>ticle ( extrane\s matt]1 :i* c s]ve z a c5tre ( *emical action4 ,?is same fact is (t5 notic$ 9 ! fad+ ( ,positives by long keep+1 & !re=e s9ce o!r de/ructive actions 7) ! exception ( t ( ,*lor9e7 d n appe> to foll[ ! same rule1 x is an argum5t 9 addition to o!rs :i* c be adduc$1 t ,photographic ,pr9ts are frequ5tly de/roy$ by oxidation4 ,air :i* has be5 ,ozoniz$ by ,phosphorus1 & 9 :i* blue litmus-pap] becomes r$d5$1 quickly blea*es ! ,positive image4 ,oxyg5 gas1 obta9$ by voltaic decomposition ( acidifi$ wat] & :i* %\ld conta9 ,ozone1 did n appe> to h an equal am\nt ( effect1 ! action be+ comp>atively slight1 or altoge!r want+4 ,p]oxide ( ,hydrog5 obta9$ 9 solution1 & 9 conjunction ) ,acetate ( ,b>yta1 by add+ ,p]oxide ( ,b>ium to dilute ,acetic ,acid1#bf blea*es d>k5$ ,positive pap]2 b ! effect is sl[1 & does n take place to a v p]ceptible ext5t if ! liquid be kept alkal9e to te/-pap]4 #bf ,hydro*loric ,acid1 :i* is usually recomm5d$ 9 place ( ,acetic ,acid1 _c be employ$ 9 ?is exp]im5t2 x seems to cause a lib]ation ( free ,*lor9e1 :i* blea*es ! pr9t in/antly4 ,nitric ,acid appli$ 9 a conc5trat$ =m acts imm$iately ^u ! d>k5$ surface1 blea*+ e "p ( ! pr9t ) ! exception ( ! bronz$ %ad[s1 :i* usually reta9 a slight residual col\r4 ,a solution ( ,*romic ,acid is /ill m active4 ,?is liquid may usefully be appli$ to di/+ui% pr9ts ton$ by ,sulphur f o!rs ton$ by ,gold2 ! pres5ce ( metallic ,gold protect+ ! %ad[s ( ! picture 9 "s measure f ! action ( ! acid4 ,! solution %\ld be prep>$ z foll[s3-- ,bi*romate ( ,pota% #f gra9s4 ,/rong ,sulphuric ,acid #d m9ims4 ,wat] #ab ounces4 ,a solution ( ,p]manganate ( ,pota% is an en]getic de/roy] ( pap] positives2 &1 z x is a neutral sub/ance1 may conv5i5tly be employ$ 9 te/+ ! relative capability ( )/&+ oxidation possess$ by diff]5t ,photographic ,pr9ts4 ,! solution %\ld be dilute1 ( a pale p9k hue1 & ! ,positives mu/ be mov$ occasionally1 z ! fir/ effect is to decolorize a great portion ( ! liquid1 ! ,p]manganate oxidiz+ ! size & organic tissue ( ! pap]4 ,aft] an imm]sion ( tw5ty m9utes to half an h\r1 v>y+ ) ! degree ( dilution1 ! half-tones ( ! picture beg9 to die out1 & ! full %ad[s become d>k] 9 col\r2 ! bronz$ portions ( ! pr9t )/& ! action long]1 b at l5g? ! :ole is *ang$ to a yell[ image mu* resembl+ 9 appe>ance ! ,photograph fad$ by ,sulphur4 ,comp>ative p]man5ce ( ,photographs treat$ ) ,p]manganate ( ,pota%4--,develop$ pr9ts prep>$ by a ,negative process )/& ! action bett] ?an o!rs4 ,b to ?is rule !re are exceptions2 mu* dep5d+ ^u ! "t ( exposure to light1 & ! ext5t to :i* ! developm5t is c>ri$4 ,^? pr9ts :i*1 be+ expos$ = a %ort "t1 & aft]w>ds /rongly develop$1 become d>k 9 col\r & vigor\s 9 outl9e1 are m p]man5t ?an o!rs :i* hav+ be5 ov]-expos$ & "u-develop$1 lose _! d>k col\r & become r$ & comp>atively fa9t 9 ! ,hyposulphite fix+ ,ba?4 ,positives develop$ ^u a surface ( ,*loride ( ,silv] on pla9 pap] d n resi/ ! oxidiz+ action s p]fectly z ^? on ,iodide ( ,silv]4 ,pr9ts develop$ ^u pap] prep>$ ) ,s]um ( ,milk conta9+ ,case9e /& bett] ?an ^? on pla9 pap]4 ,( pr9ts obta9$ by ! ord9>y process ( direct exposure to light1 ^? on pla9 pap] are ! fir/ to fade1 ! oxidiz+ action be+ mo/ se5 ^u ! half-tones4 ,! use ( ,album5 gives a great advantage4 ,develop$ pr9ts on ,album5 /& f> bett] ?an ! same ^u pla9 pap]2 & ev5 ! ,album9iz$ sun pr9ts are less injur$ by ! ,p]manganate ?an ! be/ ( ! ,negative pr9ts prep>$ )\t ,album54 ,case9e has ! same effect1 b to a less ext5t2 & z ,s]um ( ,milk almo/ inv>iably conta9s uncoagulat$ ,case9e1 its efficacy is ?us expla9$4 ,! mann] ( ton+ ! pr9t is a po9t ( importance2 previ\s sulphuration 9 an old ,hyposulphite ,ba? always facilitat+ ! oxidiz+ action4 ,action ( ,*lor9e ^u ,positive ,pr9ts4--,aque\s solution ( ,*lor9e de/roys ! ,photographic image1 *ang+ x fir/ to a violet t9t 7probably ,sub*loride71 & subsequ5tly oblit]at+ x by conv]sion into :ite ,*loride ( ,silv]4 ,! impression1 al?\gh invisible1 rema9s 9 ! pap]1 & may be develop$ 9 ! =m ( yell[ or br[n ,sulphuret ( ,silv] by ! action ( ,sulphurett$ ,hydrog54 ,x also becomes visible on exposure to light1 & assumes consid]able int5sity if ! pap] be previ\sly bru%$ ) free ,nitrate ( ,silv]4 ,sulphate ( ,iron produces no effect ^u ! invisible image ( ,*loride ( ,silv]2 b ,gallic or ,pyrogallic ,acid1 r5d]$ alkal9e by ,pota%1 conv]ts x into a black deposit4 ,! ,action ( ,*lor9e wat] usually comm5ces at ! edges & corn]s ( ! pr9t1 9 ! same mann] z t ( oxidiz+ ag5ts4 ,! pro(s ^u ,album5 are ! lea/ readily injur$1 & next1 ^? develop$ on ,iodide ( ,silv]4 ,hydro*loric ,acid4--,! liquid acid ( sp4 gr4 #aaf1 ev5 :5 free f ,*lor9e1 acts imm$iately ^u ! half-tones ( a positive pr9t1 & de/roys ! full %ad[s 9 ! c\rse ( a few h\rs2 a slight residual col\r h[ev] usually rema9s 9 ! d>ke/ p>ts4 ,! pr9ts develop$ on ,iodide ( ,silv] are ! mo/ p]man5t4 ,sulphuric1 ,acetic ,acids1 etc4--,acids ( all k9ds appe> to ex]t an injuri\s influ5ce ^u ,positive pr9ts1 & especially s ^u ! half-tones ( ! image1 ! effect v>y+ ) ! /r5g? ( ! acid & ! degree ( dilution ) wat]4 ,ev5 a vegetable acid l ,acetic gradually d>k5s ! col\r & de/roys p>tially or entirely ! fa9t outl9es ( ! picture4 ,bi*loride ( ,m]cury4--,! mo/ important p>ticul>s relat+ to ! action ( ?is te/ ^u ,photographs are well kn[n4 ,! image is ultimately conv]t$ into a :ite p[d]1 & h5ce1 9 ! case ( a ,positive pr9t1 x becomes invisible2 imm]sion 9 ,ammonia or ,hyposulphite ( ,soda h[ev] re/ores x 9 a =m (t5 resembl+ 9 t9t ! orig9al impression4 ,a po9t wor?y ( note is ! protective effect ( a deposit ( ,gold1 :i* is v m>k$1 ! pro(1 aft] ton+1 resi/+ ! action ( ! ,bi*loride = comp>atively a long "t4 ,ammonia4--,! effect ( ,ammonia ^u a pr9t is r to r$d5 ! image ?an to de/roy x2 ! half-tones become pale & fa9t1 b !y d n disappe>4 ,ton+ ) ,gold enables ! pro( to resi/ ! action ( ! /ronge/ solution ( ,ammonia1 & h5ce ,ammonia may safely be employ$ z a fix+ ag5t aft] ! use ( ! ,sel d'or ,ba?4 ,hyposulphite ( ,soda4--,a conc5trat$ solution ( ,hyposulphite ( ,soda ex]cises a gradual solv5t action ^u ! image ( ,photographic ,pr9ts1 at ! same "t t5d+ to communicate ,sulphur & to d>k5 ! col\r ( ! impression4 ,a fa9t yell[ outl9e ( ,sulphuret ( ,silv] usually rema9s aft] ! solution ( ! image is complet$4 ,develop$ pr9ts ( all k9ds1 b 9 p>ticul> ! ,talbotype pro(s ^u ,iodide ( ,silv]1 are less readily dissolv$ by ,hyposulphite ( ,soda ?an ^? obta9$ by ! direct action ( light4 ,!re is also a slight diff]5ce betwe5 pla9 & ,album9iz$ pr9ts1 :i* is 9 fav\r ( ! =m]1 ! album9iz$ pap] always los+ some:at m by imm]sion 9 ! ,hyposulphite ,ba? ?an pla9 ,*loride pap] s5sitiz$ by ,nitrate ( ,silv]4 ,cyanide ( ,potassium4--,! solv5t action ( ,cyanide ( ,potassium is mo/ en]getic ^u ,photographs =m$ on pap]4 ,^! images1 :e!r develop$ or n1 d n )/& ! te/ s well z ! impressions on ,collodion4 ,album9iz$ pro(s are also some:at m easily affect$ ?an pr9ts on simple ,*loride pap] s5sitiz$ ) ,nitrate or ,ammonio-,nitrate ( ,silv]4 ,heat1 moi/ & dry4--,long-cont9u$ boil+ 9 di/ill$ wat] has a r$d5+ action ^u ,positive ,pr9ts4 ,! image becomes at l5g? pale & fa9t1 resembl+ a pr9t treat$ ) ,ammonia be=e ton+4 ,a deposit ( ,gold ^u ! image less5s1 b does n altoge!r neutralize1 ! effect ( ! hot wat]4 ,if ! boil+ be long cont9u$1 ! violet-purple tone (t5 imp>t$ by ! ,gold inv>iably gives place to a *ocolate-br[n1 :i* appe>s to be ! mo/ p]man5t col\r4 ,pr9ts develop$ by ,gallic ,acid ^u pap] prep>$ ) ,s]um ( ,milk or ) a ,citrate1 suff] z mu* z o!rs obta9$ by direct action ( light4 ,ammonio-,nitrate pr9ts on highly salt$ pap]1 :i* become ne>ly black :5 ton$ ) ,gold1 reta9 _! orig9al appe>ance ! mo/ p]fectly2 a slight dim9ution ( brightness be+ ! only obs]vable diff]5ce aft] long boil+ 9 wat]4 ,album5 pro(s1 & pr9ts on ,engli% pap]s1 or =eign pap]s prep>$ ) ,s]um ( ,milk1 ,citrates1 ,t>trates1 or any ( ^? bodies :i* r$d5 ! r$uc$ ,salt1 are1 z a rule1 r5d]$ light] 9 col\r1 & pass f purple to br[n :5 boil$ 9 wat]4 ,dry heat has an opposite effect to t ( hot wat]1 usually d>k5+ ! col\r ( ! image4 ,on expos+ a pla9 pap] pr9t simply fix$1 & ?or\ghly fre$ f ,hyposulphite ( ,soda by wa%+1 to a curr5t ( heat$ air1 x *anges gradually f r$ to d>k br[n1 9 :i* /ate x cont9ues until ! temp]ature rises to ! po9t at :i* ! pap] beg9s to *>1 :5 x resumes its orig9al r$ tone1 becom+ at ! same "t fa9t & indi/9ct4 ,! ,products ( ,combu/ion ( ,coal-gas a cause ( ,fad+4--,coal-gas conta9s ,sulphur comp\nds1 :i* 9 combu/ion are oxidiz$ into ,sulphur\s & ,sulphuric ,acids2 o!r sub/ances ( a delet]i\s nature may also be pres5t4 ,a plate ( poli%$ silv] susp5d$ 9 a glass tube1 ?r\gh :i* 0 direct$ ! curr5t ( heat$ air ris+ f a small gas jet1 became t>ni%$ ) a :ite film 9 ! c\rse ( tw5ty-f\r h\rs4 ,positive pr9ts expos$ to ! same1 absorb$ moi/ure & fad$2 ! action resembl+ t ( oxidation1 9 be+ prec$$ by a g5]al d>k5+ 9 col\r4 ,( f\r pr9ts expos$1 an ,iodide-develop$ pr9t 0 ! lea/ injur$1 & next1 a pr9t ^u ,album9iz$ pap]4 ,,on ,,! ,,action ,,( ,,damp ,,air ,,^u ,,positive ,,pr9ts4 ,9 ord] to asc]ta9 ?is po9t1 m ?an six doz5 ,positives1 pr9t$ on e v>iety ( pap]1 7 m\nt$ 9 new & p]fectly clean /opp]$ glass bottles1 at ! bottom ( ea* ( :i* 0 plac$ a little di/ill$ wat]1 to keep ! conta9$ air always moi/4 ,!y 7 remov$ at ! expiration ( ?ree mon?s1 hav+ be5 kept dur+ t "t1 "s 9 ! d>k1 & o!rs expos$ to ! light4 ,z ! pr9ts 7 prep>$ by v>i\s me?ods1 ton$ 9 diff]5t ways1 & m\nt$ ) or )\t sub/ances likely to ex]cise a delet]i\s action1 ?is s]ies ( exp]im5ts w possess consid]able value 9 det]m9+ "s ( ! intr9sic causes ( fad+ ( ,positives4#bg #bg ,= a m detail$ acc\nt ( ! exp]im5ts1 see ! orig9al pap] 9 ! ',photographic ,j\rnal1' vol4 iii4 ,! g5]al results obta9$ 7 z foll[s3--,positives :i* _h be5 simply fix$ 9 ,hyposulphite ( ,soda rema9$ q un9jur$4 ,:e!r develop$ by ,gallic ,acid on ei!r ( ! ?ree ,salts ( ,silv] usually employ$1 or pr9t$ by direct action ( light1 ! result 0 ! same4 ,h5ce we may inf] t ! d>k5$ mat]ial :i* =ms ! image ( ,photographic ,pr9ts does n readily oxidize 9 a damp atmosph]e4 ,ton$ ,positives 7 f\nd 9 _m cases to be less p]man5t ?an ,positives simply fix$4 ,?is 0 especially ! case :5 ! ton+ _h be5 effect$ by ,sulphur2 all ! sulphurett$ pr9ts1 fix$ 9 solution ( ,hyposulphite :i* _h be5 long us$1 became yell[ 9 ! half-tones :5 expos$ to moi/ure4 ,positives fix$ & ton$ 9 ,hyposulphite conta9+ ,gold 7 v>i\sly affect$2 "s prep>$ :5 ! solution 0 9 an active /ate be+ un*ang$1 o!rs los+ a little half-tone1 & o!rs1 aga91 fad+ badly4 ,^! latt] 7 prep>$ 9 a ,ba? :i* _h lo/ ,gold & acquir$ sulphurett+ prop]ties2 & x 0 notic$ t !y 7 m injur$ by ! action ( boil+ wat] ?an ^? ,positives :i* prov$ to be p]man5t "u ! influ5ce ( ! moi/ure4 ,ton+ by means ( ,*loride ( ,gold appe>$ to be highly satisfactory1 b ! numb] ( pr9ts op]at$ ^u 0 small4 ,! ,sel d'or process also did n injure ! integrity ( ! image1 no comm5c+ yell[ness or blea*+ ( half-tones be+ visible aft] exposure to ! moi/ air4 ,?is s]ies ( exp]im5ts confirm$ ! /atem5t made 9 a =m] pap]1 t "s t9ts obta9$ 9 ,positive pr9t+ are m p]man5t ?an o!rs4 ,violet tones produc$ by ,sulphur inv>iably pass$ into a dull br[n by ! action ( ! moi/ air2 & ev5 :5 ,gold 0 employ$ 9 ton+1 ^! same purple col\rs 7 usually r$d5$4 ,?is 0 especially ! case :5 ,engli% pap]s 7 us$1 or =eign pap]s re-siz$ ) ,s]um ( ,milk conta9+ ,case9e4 ,! *ocolate-br[n t9ts :i* be/ /& ! action ( boil+ wat]1 & 9 p>ticul> ^? ^u ,ammonio-,nitrate pap]1 7 lea/ affect$ by ! damp air2 & inde$ x 0 evid5t t ! two ag5ts1 viz4 moi/ air & hot wat]1 act$ alike 9 t5d+ to r$d5 ! pr9t1 al?\gh ! latt] did s 9 ! mo/ m>k$ mann]4 ,x seem$ also1 f ! results ( ^! exp]im5ts1 to be a po9t ( great importance t ! size %\ld be remov$ f ! pr9t 9 ord] to r5d] x inde/ructible by damp air4 ,?is 0 evid5tly se5 9 two cases :]e ,positives1 ton$ 9 an old ,hyposulphite & ,gold ,ba?1 7 divid$ into halves1 "o ( :i* 0 treat$ ) a /rong solution ( ,ammonia4 ,! result 0 t ! halves 9 :i* ! size 0 all[$ to rema91 fad$1 :il/ ! o!rs 7 comp>atively un9jur$4 ,! ,album5 pro(s especially suff]$ :5 ! size 0 left 9 ! pap]1 a de/ructive m\ld9ess =m+1 & fad+ ! picture4 ,! use ( boil+ wat] obviat$ ?is1 & ! pr9ts s treat$ rema9$ clean & bright4 ,a p>tial decomposition ( ,album5 h[ev] occurr$ 9 "s cases ev5 :5 hot wat] 0 us$1 ! gloss disappe>+ f ! pap] 9 isolat$ pat*es4 ,) ,case9e sub/itut$ = ,album5 !re 0 also a loss ( half-tone2 ?us seem+ to indicate t bo? ^! animal pr9ciples1 al?\gh /able "u ord9>y conditions1 w1 ev5 :5 coagulat$ by ,nitrate ( ,silv]1 decompose if kept long 9 a moi/ /ate4 ,! use ( improp] sub/ances = m\nt+ prov$ to be ano!r det]m9+ cause ( fad+ by oxidation4 ,^? bodies :i* comb9e ) ,oxide ( ,silv]1 are likely ^u !oretical gr\nds to de/roy ! half-tones ( ! image2 & x 0 f\nd1 t if ! picture 7 left 9 contact ) ,alum1 ,acetic ,acid1 etc41 or ) ! sub/ances :i* g5]ate an acid by f]m5tation1 su* z pa/e or />*1 x inv>iably fad$4 ,! suppos$ accel]at+ influ5ce ( ,light ^u ! fad+ ( ,positives 0 n confirm$ by ^! exp]im5ts1 z f> z !y ext5d$4 ,_m ( ! bottles conta9+ ! ,photographs 7 plac$ outside ! w9d[ ( a h\se ) a s\!rn aspect dur+ ! :ole ( ! ?ree mon?s ) ! exception ( two or ?ree weeks1 b no diff]5ce :atev] c\ld be detect$ betwe5 ,positives s treat$ & o!rs kept 9 total d>kness4 ,x w be prop] h[ev] t ?is "p ( ! inve/igation %\ld be repeat$1 all[+ a long] "t4 ,an exam9ation ( ! v>i\s modes employ$ = coat+ ,positives1 9 ord] to exclude ! atmosph]e1 %[$ t _m ( !m 7 n fitt$ to fulfil ! purpose int5d$4 ,wax$ pr9ts fad$ q z mu* :5 expos$ to moi/ure z o!rs n wax$4 ,:ite wax is a sub/ance (t5 adult]at$1 & ,oil ( ,turp5t9e has be5 %[n to conta9 a body resembl+ ,ozone 9 prop]ties1 & possess+ ! p[] ( blea*+ a dilute solution ( ,sulphate ( ,indigo4 ,_s v>ni% appli$ to ! surface ( ! picture aft] re-siz+ ) ,gelat9e 0 pla9ly sup]ior to :ite wax1 b nev]!less x did n obviate ! fad+ effect ( ! moi/ure ^u an un/able ,positive :i* _h be5 ton$ by sulphuration4 ,its protective influ5ce is !re=e limit$4 ,,on ,,! ,,*ange ,,9 ,,composition ,,:i* ,,hyposulphite ,,( ,,soda ,,exp]i5ces ,,by ,,use ,,9 ,,fix+ ,,pap] ,,pro(s4#bh #bh ,^! obs]vations are cond5s$ & re-arrang$ f ! pap]s publi%$ by ! ,au?or 9 ! ',photographic ,j\rnal' = ,septemb] & ,octob]1 #ahed4 ,x 0 rem>k$ by ,photograph]s at an e>ly p]iod t ! prop]ties ( ! ,fix+ ,ba? ( ,hyposulphite ( ,soda became alt]$ by con/ant use2 t x gradually acquir$ ! p[] ( d>k5+ ! col\r ( ! ,positive image4 ,?is *ange 0 at fir/ ref]r$ to ! accumulation ( ,salts ( ,silv] 9 ! ,ba?1 & h5ce directions 7 giv5 to dissolve a portion ( black5$ ,*loride ( ,silv] 9 ! ,hyposulphite 9 prep>+ a new solution4 ,c>eful exp]im5ts p]=m$ by ! ,au?or conv9c$ him t an error _h be5 ent]ta9$2 s9ce x 0 f\nd t ! simple solution ( ,*loride ( ,silv] 9 ,hyposulphite ( ,soda _h no p[] ( yield+ ! black tones4 ,b x aft]w>ds appe>$ t if ! fix+ ,ba?1 conta9+ dissolv$ ,silv] ,salts1 7 set aside = a few weeks1 a decomposition occurr$ 9 x1 evid5c$ by ! =mation ( a black deposit ( ,sulphuret ( ,silv]2 & !n x became active 9 ton+ ! pro(s4 ,! pres5ce ( ?is deposit ( ,sulphuret ( ,silv] indicat$ t a portion ( ,hyposulphite ( ,silv] _h spontane\sly decompos$1 &1 kn[+ ! products :i* are g5]at$ by ! spontane\s decomposition ( ?is salt1 a clue to ! difficulty 0 af=d$4 ,"o atom ( ,hyposulphite ( ,silv] includes ! elem5ts ( "o ( ,sulphuret ( ,silv] & "o ( ,sulphuric ,acid4 ,sulphuric ,acid 9 contact ) ,hyposulphite ( ,soda produces ,sulphur\s ,acid by a process ( displacem5t2 & ,plessy has %[n t ,sulphur\s ,acid reacts ^u an excess ( ,hyposulphite ( ,soda1 =m+ two ( t int]e/+ s]ies ( ,sulphur comp\nds designat$ by ,b]zelius ! ,poly?ionic ,acids4 ,x appe>$ !re=e probable1 ^u !oretical gr\nds1 t ! ,p5ta-1 ,tetra-1 & ,tri?ionates might produce "s effect 9 ! ,hyposulphite fix+ ,ba?4 ,^u mak+ ! trial ^! expectations 7 v]ifi$2 & x 0 f\nd t ,tetra?ionate ( ,soda add$ to ,hyposulphite ( ,soda yield$ a fix+ & ton+ ,ba? q equal 9 activity to t produc$ by means ( ,*loride ( ,gold4 ,x may be useful to review = an in/ant ! composition ( ! ,poly?ionic s]ies ( acids2 x is ?us repres5t$3-- ,sulphur4 ,oxyg54 ,=mul4 ,di?ionic or ,hyposulphuric ,acid #b atoms #e atoms ,s#b,o#e ,tri?ionic ,acid #c #e ,s#c,o#e ,tetra?ionic ,acid #d #e ,s#d,o#e ,p5ta?ionic ,acid #e #e ,s#e,o#e ,! am\nt ( ,oxyg5 9 all is ! same1 t ( ! o!r elem5t increases progressively2 h5ce x is at once evid5t t ! highe/ memb] ( ! s]ies might by los+ ,sulphur desc5d gradually until x rea*$ ! condition ( ! l[e/4 ,?is transition is n only !oretically possible1 b !re is an actual t5d5cy to x1 all ! acids be+ un/able ) ! exception ( ! ,hyposulphuric4 ,! ,alkal9e ,salts ( ^! acids are m un/able ?an ! acids !mselves2 a solution ( ,tetra?ionate ( ,soda becomes milky 9 ! c\rse ( a few days f deposition ( ,sulphur1 &1 if te/$1 is !n f\nd to conta9 ,tri?ionate & ev5tually ,di?ionate ( ,soda4 ,! cause ( ! *ange 9 prop]ties ( ! fix+ ,ba? be+ ?us cle>ly trac$ to a decomposition ( ,hyposulphite ( ,silv]1 & a consequ5t g5]ation ( un/able pr9ciples capable ( imp>t+ ,sulphur to ! imm]s$ pro(s1 x seem$ desirable to cont9ue ! exp]im5ts4-- ,!re is a peculi> acid condition commonly assum$ by old fix+ ,ba?s1 :i* c\ld n be satisfactorily expla9$1 s9ce x 0 kn[n t acids d n exi/ long 9 a free /ate 9 solution ( ,hyposulphite ( ,soda1 b t5d to neutralize !mselves by displac+ ,hyposulphur\s ,acid spontane\sly decomposable into ,sulphur\s ,acid & ,sulphur4 ,?is po9t is set at re/ by ! discov]y ( a peculi> reaction :i* takes place betwe5 c]ta9 salts ( ! ,poly?ionic acids & ,hyposulphite ( ,soda4 ,a solution ( ,tetra?ionate ( ,soda may be pres]v$ = _m h\rs un*ang$2 b if a few cry/als ( ,hyposulphite ( ,soda be dropp$ 91 x beg9s v %ortly to deposit ,sulphur1 & cont9ues to d s = sev]al days4 ,at ! same "t ! liquid acquires an acid reaction to te/-pap]1 & produces eff]vesc5ce on ! addition ( ,c>bonate ( ,lime4 ,x is evid5t t a ,sulphur acid exi/s :i* has n hi!rto be5 describ$1 & t ?is acid is =m$ z "o ( ! products ( ! decomposition ( ! ,hyposulphite ( ,silv] conta9$ 9 ! fix+ ,ba?4 ,! subject is an important "o to ,photograph]s1 because x is f\nd t ,hyposulphite ,ba?s :i* h acquir$ ! acid reaction1 al?\gh ton+ quickly1 yield ,positives :i* fade on keep+4 ,! acid may p]haps comb9e ) ! r$uc$ ,silv] ,salt1 :i*1 if ! image be all[$ to conta9 ,suboxide ( ,silv]1 is !oretically probable4 ,! exp]im5ts 7 next direct$ t[>ds asc]ta9+ m c>efully ! effect ( ! acid fix+ ,ba? ^u ! ,positive pro(s4 ,tetra?ionate ( ,soda add$ to solution ( ,hyposulphite ( ,soda produces1 at ! expiration ( twelve h\rs1 a liquid :i*1 :5 filt]$ f ! deposit$ ,sulphur1 r$d5s blue litmus-pap] sl[ly4 ,positive pr9ts imm]s$ 9 ! ,ba? pass f r$ to black1 dissolv+ 9 ! half-tones1 & becom+ yell[ & fad$ if ! action be too long cont9u$4 ,on add+ ,c>bonate ( ,soda 9 quantity suffici5t to remove ! acid reaction1 ! p[] ( ton+ is mu* dim9i%$1 b d>k col\rs c /ill be obta9$ by cont9u+ ! action4 ,! solv5t effect ^u ! half-tones1 evid5tly caus$ 9 great measure by ! acid1 is less5$2 :il/ ! t5d5cy to yell[ness 9 ! :ite p>ts ( ! pro(1 almo/ disappe>s4 ,^! effects are m p>ticul>ly manife/$ :5 ! pr9ts are imm]s$ 9 ! ,ba? imm$iately on _! removal f ! pr9t+ frame2 & x is f\nd almo/ impossible to pres]ve ! :ites ( ! impression cle>1 9 ! acid ,ba?1 unless ! ,nitrate ( ,silv] has be5 wa%$ away4 ,solution ( half-tones & yell[ness 9 ! lights1 bo? a s\rce ( annoyance to ! op]ator1 are ?us trac$ 9 great measure to an acid condition ( ! fix+ & ton+ ,ba?2 & ! rem$y is obvi\s4 ,! ,au?or's exp]im5ts ^u ! ,tetra?ionates & _! reaction ) ,hyposulphite ( ,soda likewise elicit$ ! important fact t alkalies decompose ! un/able sulphurett$ pr9ciple4 ,if ! ,ba? be treat$ ) ,pota% or ,c>bonate ( ,soda1 an alkal9e ,sulphuret appe>s to be gradually =m$1 :i* precipitates ,sulphuret ( ,silv]1 & 9 ! c\rse ( a few days ! liquid returns to its orig9al condition & ceases to act z a ton+ ag5t ^u ! pro(4 ,! same effect takes place to a great ext5t :5 ! solution is set aside = sev]al weeks or mon?s2 a process ( spontane\s *ange go+ =w>d1 :i* issues 9 a deposition ( ,sulphur & ,sulphuret ( ,silv]1 & a p>tial loss ( sulphurett+ prop]ties 9 ! liquid4 ,x may be int]e/+ to ! sci5tific inve/igator to describe ! mode ( prep>+ a fix+ & ton+ ,ba?1 illu/rat+ ! above rem>ks3-- ,take ( ,nitrate ( ,silv] #c dra*ms4 ,hyposulphite ( ,soda #d ounces4 ,wat] #h ounces4 ,dissolve ! ,nitrate ( ,silv] 9 #b ounces ( ! wat]1 !n f ! total quantity ( ,hyposulphite ( ,soda1 weigh out ,hyposulphite ( ,soda #b dra*ms2 dissolve ?is likewise 9 #b ounces ( wat]1 & ! rema9d] ( ! ,hyposulphite 9 ! o!r #d ounces4 ,!n1 hav+ ! ?ree solutions 9 sep>ate vessels1 p\r ! ,nitrate ( ,silv] at once into ! #b-ounce solution ( ,hyposulphite1 agitat+ ! precipitat$ ,hyposulphite ( ,silv] rapidly4 ,9 a %ort "t x w beg9 to decompose1 pass+ f :ite to can>y-yell[1 & !n to orange-yell[4 ,:5 ! orange-yell[ beg9s to v]ge t[>ds br[n1 add ! #d-ounce conc5trat$ solution ( ,hyposulphite1 :i* w at once complete ! decomposition1 a "p ( ! precipitate dissolv+ & ! rema9d] becom+ p]fectly black4 ,aft] filt]+ out ! black ,sulphuret ( ,silv]1 ! solution is ready = use4 ,a ,ba? prep>$ by ?is =mula is n usually v active1 b x %[s cle>ly ! process by :i* an ord9>y fix+ ,ba? may be conv]t$ into a ton+ ,ba? by ! imm]sion ( positives hav+ free ,nitrate ( ,silv] ^u ! surface4 ,! foll[+ =mula is m economical & gives a bett] result1 b x _c be us$ = ,ammonio-,nitrate pr9ts2 ! addition ( an alkali precipitat+ ,sulphuret ( ,iron4 ,/rong solution ( ,p]*loride ( ,iron #f fluid dra*ms4 ,hyposulphite ( ,soda #d ounces4 ,wat] #h ounces4 ,nitrate ( ,silv] #cj gra9s4 ,dissolve ! ,hyposulphite ( ,soda 9 sev5 ounces ( ! wat]1 ! ,nitrate ( ,silv] 9 ! rema9+ "o ounce2 !n p\r ! ,p]*loride ( ,iron into ! solution ( ,hyposulphite1 by degrees1 /irr+ all ! "t4 ,! addition ( ! ,iron ,salt /rikes a f9e purple col\r1 b ?is soon disappe>s4 ,:5 ! liquid has become aga9 col\rless1 :i* x does 9 a few m9utes1 add ! ,nitrate ( ,silv]1 /irr+ briskly4 ,p]fect solution w take place )\t any =mation ( black ,sulphuret4 ,a ton+ ,ba? prep>$ ) ,*loride ( ,iron w be ready = use twelve h\rs aft] mix+1 b x w be m active at ! expiration ( a week4 ,! solution is acid to te/-pap]1 & milky f a deposit ( ,sulphur1 :i* mu/ be filt]$ out4 ,! ,p]*loride ( ,iron %\ld be prep>$ by boil+ ,p]oxide ( ,iron ) ,hydro*loric ,acid1 9 pref]5ce to dissolv+ ,iron wire 9 ,aqua-,regia4 ,! addition ( ! ,nitrate ( ,silv] is made 9 ord] to produce a portion ( ,hyposulphite ( ,silv] 9 ! ba?2 ! pres5ce ( a ,silv] ,salt hav+ be5 f\nd to modify ! t9t ( ! ,positives1 & to prev5t _! quickly turn+ yell[4 ,,section ,,iv4 ,on ! ,fad+ ( ,photographic ,pr9ts4 ,= _m ye>s subsequ5t to ! discov]y ( ! process ( ,photographic ,pr9t+ by ,mr4 ,fox ,talbot1 x 0 n g5]ally kn[n t pictures s produc$ 7 easily susceptible ( injury f v>i\s causes1 & 9 p>ticul> f traces ( ! fix+-ag5t rema9+ 9 ! pap]4 ,h5ce1 due c>e n be+ tak5 9 ! prop] cleans+ & pres]vation ( ! pro(s1 ! majority ( !m fad$4 ,?is matt] became at la/ "o ( su* importance t ! ,c\ncil ( ! ,photographic ,society decid$ ^u =m+ a ,committee = ! purpose ( exam9+ ! subject4 ,! ,au?or 0 hon\r$ by be+ plac$ ^u ?is ,committee1 & ! rese>*es ( :i* an ab/ract has be5 giv5 9 ! previ\s ,section1 7 und]tak5 at ! reque/ ( ! ,society4 ,! pres5t ,section is int5d$ to expla9 practically & 9 a concise mann] ! causes ( ! fad+ ( ,photographic ,pr9ts1 & ! precautions :i* %\ld be tak5 to ensure _! p]man5cy4 ,! *emi/ry ( ! subject hav+ be5 fully expla9$ 9 ! la/ ,section1 x w suffice to ref] ! read] to its pages = m detail$ in=mation4 ,hi/orical evid5ce ( ! p]man5ce ( ,photographs4--,x is a po9t ( int]e/ to collect in=mation z to ! exi/5ce ( old ,photographs :i* h rema9$ _m ye>s un*ang$4 ,!re are num]\s in/ances ( ,positives pr9t$ m ?an t5 ye>s ago1 :i* h n p]ceptibly alt]$ up to ! pres5t "t4 ,^! pr9ts are mo/ly on pla9 pap]1 ,album5 n hav+ come into use at s e>ly a date4 ,! g5]al impression ( practical op]ators h[ev] is1 t fad+ has occurr$ less frequ5tly s9ce ! introduction ( ,album9iz$ pap]4 ,positives pr9t$ by developm5t on pap] prep>$ by ,talbot's me?od seem z a rule to h /ood rem>kably well1 & in/ances ( ,talbotype ,negatives hav+ fad$ are r>e4 ,( ! pr9ts :i* h prov$ to be p]man5t1 "s are r$ or br[n 9 col\r1 b _m1 be+ ( a d>k or purple %ade1 h evid5tly be5 ton$1 al?\gh n ) ,gold1 ! use ( :i* 0 unkn[n to ! e>li] ,photograph]s4 ,x is pla9 f data ?us collect$1 t ,photographs d n necess>ily fade by "t2 & ! fact t 9 "o & ! same portfolio are con/antly se5 pr9ts :i* appe> p]man5t1 & o!rs 9 an advanc$ /ate ( *ange1 _c b lead to ! inf]5ce t ! ma9 causes ( det]ioration are intr9sic1 dep5d+ ^u "s injuri\s matt]s left 9 ! pap]2 :i* is confirm$ by exp]im5t4 ,causes ( fad+4--,! ,au?or believes t ! fad+ ( ,photographic ,pr9ts may almo/ inv>iably be ref]r$ to "o or o!r ( ! foll[+ conditions3-- a4 ,imp]fect wa%+4--,?is is p]haps ! mo/ important ( all1 & ! mo/ frequ5t4 ,:5 ,hyposulphite ( ,soda is all[$ to rema9 9 ! pap]1 ev5 9 m9ute quantity1 x gradually decomposes1 ) lib]ation ( ,sulphur1 & de/roys ! pr9t 9 ! same way & q z effectually z a solution ( ,sulphurett$ ,hydrog5 or an alkal9e sulphuret4 ,imp]fect wa%+ may be suspect$1 if ! ,photograph1 )9 a few mon?s f ! date ( its prep>ation1 beg9s to get d>k] 9 col\r3 ! half-t9ts1 :i* are ! fir/ to %[ ! action1 aft]w>ds pass+ into ! yell[ /age1 :il/ ! d>k %ad[s rema9 black or br[n = a long] "t4 ,! prop] mode ( wa%+ ,photographs is sometimes misund]/ood4 ,! l5g? ( "t dur+ :i* ! pr9t lies 9 ! wat] is a po9t ( less importance1 ?an t ! wat] %\ld be cont9ually *ang$4 ,:5 a numb] ( ,positives are plac$ toge!r 9 a pan1 & a tap turn$ ^u !m1 ! circulation ( fluid does n necess>ily ext5d to ! bottom4 ,?is is prov$ by ! addition ( a little col\r+ matt]1 :i* %[s t ! /ream fl[s actively above1 b at ! l[] "p ( ! vessel1 & betwe5 ! pr9ts1 !re is a /ation>y lay] ( wat] :i* is ( little use 9 wa%+ out ! ,hyposulphite4 ,c>e %\ld !re=e be tak5 t ! pictures are kept z f> z possible sep>ate f ea* o!r1 & :5 runn+ wat] _c be _h1 t !y are frequ5tly mov$ & turn$ ov]1 fre% wat] be+ con/antly add$4 ,:5 ?is is done1 & especially if ! size be remov$ f ! pap] 9 ! mann] pres5tly to be advis$1 f\r or five h\rs wa%+ w be suffici5t4 ,x is a mi/ake to all[ ! pictures to rema9 9 ! wat] = sev]al days2 :i* produces no good effect1 & may t5d to enc\rage a putrefactive f]m5tation1 or ! =mation ( a :ite deposit ^u ! image :5 ! wat] conta9s ,c>bonate ( ,lime4 b4 ,acid matt]s left 9 ! ,pap]4--,^u exam9+ collections ( old ,photographs1 x is n uncommon to f9d pr9ts :i* are /at$ to h rema9$ unalt]$ = a long "t aft] _! fir/ production1 b 9 ! c\rse ( "t to h lo/ _! brilliancy1 & become pale & indi/9ct4 ,?is k9d ( fad+ (t5 comm5ces at ! corn]s & edges ( ! pap]1 & works inw>ds t[>ds ! c5tre4 ,! ,au?or's exp]im5ts h %[n t x is pr9cipally caus$ by a sl[ process ( oxidation4 ,! ,photographic ,image does n appe> readily susceptible ( oxidation unless x be previ\sly d>k5$ by ! action ( ,sulphur1 or plac$ 9 contact ) acids or bodies :i* act z solv5ts ( ,oxide ( ,silv] 7p4 #adf74 ,! mat]ials (t5 us$ 9 siz+ pap]s1 su* z ,alum & ,res91 be+ ( an acid nature1 are directly injuri\s to ! image2 & ! removal ( ! size1 :i* may easily be effect$ by means ( a dilute alkali or an alkal9e c>bonate1 )\t injury to ! t9t1 has ! additional advantage ( c>ry+ out ! la/ traces ( ,hyposulphite ( ,soda1 & also ! g]ms ( fungi1 :i* if all[$ to rema9 w\ld vegetate & produce a de/ructive m\ld9ess on exposure to damp 7,*ap4 ,,iii4 ,"p ,,ii474 ,! fact t acids facilitate oxidation ( ! image is likewise a h9t t ,photographic ,pr9ts %\ld n be h&l$ too frequ5tly1 or t\*$ ) ! f+] m ?an is necess>y2 ! w>m h& may leave beh9d a trace ( acid#bi :i* w\ld t5d 9 "t to produce a yell[ m>k4 #bi ,! writ] has se5 blue litmus-pap] imm$iately r$d5$ by be+ laid ^u ! arm ( a p]son suff]+ f acute ,rheumatism4 ,?is acid is probably ,lactic ,acid6 c4 ,moi/ure z a cause ( fad+4--,al?\gh4 ,photographs prop]ly pr9t$ are n readily injur$ by damp air 7p4 #aec71 yet z !re are impurities ( v>i\s k9ds con/antly float+ 9 ! atmosph]e1 a /ate ( comp>ative dryness may be said to be ess5tial to ! pres]vation ( all ,photographs4 ,9 collect+ evid5ce ^u ! subject1 wet & damp are frequ5tly alleg$ z hav+ be5 causes ( fad+--! pr9ts 7 hung aga9/ a damp wall dur+ fro/y wea!r1 9 a room )\t a fire3 or ! ra9 _h be5 all[$ to p5etrate ! frame6 ,no pictures w long survive su* treatm5t1 & ,photographs1 l engrav+s & wat]-col\r pa9t+s1 require common c>e to be ex]cis$ 9 _! pres]vation4 d4 ,! modes ( ,m\nt+ ! ,pro(4--,?is subject has be5 allud$ to 9 ! ab/ract ( ! ,au?or's pap]s at p4 #aee4 ,all cem5ts :i* are ( an acid nature1 or :i* are liable to become s\r by acet\s f]m5tation1 %\ld be avoid$4 ,fl\r pa/e is especially injuri\s1 & _m cases ( fad+ h be5 trac$ to ?is cause4 ,! addition ( ,bi*loride ( ,m]cury1 :i* is (t5 made to prev5t ! pa/e f becom+ m\ldy1 w\ld /ill m unfit x = ,photographic use 7p4 #aea74 ,/>* is n mu* pref]able4 ,no sub/ance appe>s bett] ?an ,gelat9e1 :i* does n readily decompose1 & %[s no t5d5cy to absorb atmosph]ic moi/ure4 ,! deliquesc5t nature ( _m bodies is a po9t :i* %\ld be borne 9 m9d 9 m\nt+ ,photographs1 & h5ce ! use ( a salt l ,c>bonate ( ,pota%1 :i* ! writ] has kn[n to be add$ to pa/e to prev5t ! =mation ( acid1 w\ld be unadvisable4 e4 ,! effect ( ,imp]fect ,fixation4--,! e>li] ,photograph]s did n always succe$ 9 prop]ly fix+ _! pr9ts1 s9ce old ,photographs are (t5 f\nd ?ickly /udd$ ) spots & blot*es 9 ! tissue ( ! pap]4 ,^! pr9ts h[ev] are n inv>iably fad$ ^u ! surface1 & h5ce x _c be said t imp]fect fixation w c]ta9ly end 9 ! total de/ruction ( ! picture4 ,/ill a notice ( ! subject may prop]ly be introduc$ 9 ?is place1 & ! att5tion ( ! read] be once m drawn to ! importance ( wa%+ ! pr9t 9 wat] on remov+ x f ! pr9t+ frame2 a decomposition inv>iably occurr+ :5 pap] ,positives saturat$ ) free ,nitrate ( ,silv] are plung$ 9 a dilute solution ( ,hyposulphite ( ,soda1 conta9+ an insuffici5t quantity ( ! salt to dissolve away ! ,hyposulphite ( ,silv] be=e x beg9s to und]go spontane\s *ange4 f4 ,exposure to an impure ,atmosph]e z a cause ( ,fad+4--,! five causes ( fad+ :i* prec$e1 h mo/ly ref]5ce to an intr9sically faulty condition ( ! pr9t4 ,?is1 ! six?1 expla9s ! mode 9 :i* a ,photograph c>efully prep>$ may yet suff] injury f delet]i\s matt]s (t5 pres5t 9 ! atmosph]e4 ,! air ( l>ge cities1 & p>ticul>ly t emanat+ f sew]s & dra9s1 conta9s ,sulphurett$ ,hydrog51 & h5ce articles ( silv]-plate become t>ni%$ unless plac$ b5ea? glass4 ,! injury :i* a pr9t su/a9s by exposure to air contam9at$ ) ,sulphurett$ ,hydrog51 is less ?an ! t>ni% produc$ ^u ! bright surface ( a silv] plate 7see p4 #adh72 b x is recomm5d$ z a precaution>y measure1 t ,photographic ,pictures be protect$ by glass or kept 9 a portfolio1 & t !y be n expos$ too freely to ! air4 ,! products ( ! combu/ion ( coal-gas are probably m likely ?an ! cause la/ nam$1 to be a s\rce ( injury to ,photographs susp5d$ )\t any cov]+4 ,! sulphur comp\nds 9 gas burn into ,sulphur\s & ,sulphuric ,acids1 ! latt] ( :i*1 9 comb9ation ) ,ammonia1 produces ! sp>kl+ cry/als (t5 obs]v$ ^u ! %op w9d[s4 ,! "q z to ! mann] 9 :i* ! ,photographic ,image may be/ be protect$ f ^! extrane\s causes ( fad+ has be5 moot$1 & _m plans ( coat+ pr9ts ) "s imp]vi\s mat]ial h be5 devis$4 ,if ! pictures are to be glaz$ or kept 9 a portfolio1 ?is ( itself w be suffici5t1 b 9 o!r cases x may p]haps be useful to apply a lay] ( _s or gutta-p]*a v>ni%4 ,! use ( wax1 res91 & su* bodies is likely1 by introduc+ impurities1 to act injuri\sly r ?an o!rwise4 g4 ,decomposition ( ,pyroxyl9e a s\rce ( ,injury to ,collodion ,photographs4--,collodion ,positives & ,negatives are usually e/eem$ p]man5t2 b "s h be5 exhibit$ :i*1 hav+ be5 put away 9 a damp place1 gradually became pale & indi/9ct4 ,! *ange comm5ces at r\gh edges & isolat$ po9ts1 leav+ ! c5tre1 z a rule1 ! la/ affect$4 ,on exam9ation1 num]\s cracks are (t5 visible1 ?us seem+ to indicate t ! ,collodion film has und]gone decomposition4 ,! result ( ?is w\ld be ! lib]ation ( corrosive ,oxides ( ,nitrog51 :i* de/roy ! image4 ,sub/itution comp\nds conta9+ ,p]oxide ( ,nitrog5 are kn[n to be liable to spontane\s *ange4 ,! bitt] res9 produc$ by act+ ^u :ite sug> ) ,nitro-,sulphuric ,acid1 if n kept p]fectly dry1 w sometimes evolve en\gh gas to de/roy ! cork ( ! bottle 9 :i* x is kept2 ! solution ( ! res9 has !n a /rong acid reaction1 & rapidly fades an ord9>y ,positive ,pr9t4 ,^! facts are int]e/+1 & indicate t ,collodion ,pictures1 conta9+ 9 !mselves ! elem5ts ( _! de/ruction1 %\ld be protect$ f moi/ure by a coat+ ( v>ni%4 ,comp>ative ,p]man5ce ( ,photographic ,pr9ts4--,!re is e reason to ?9k t ! ,photographic ,image1 h[ev] =m$1 is p]man5t1 if c]ta9 injuri\s conditions are avoid$2--9 o!r words1 t pr9ts d n necess>ily fade1 9 ! same mann] z fugitive col\rs1 by a simple exposure to light & air4 ,b suppos+ a case1 :i* is ! common "o1 ( injuri\s influ5ces :i* _c altoge!r be remov$1 x may be useful to inquire :at mode ( pr9t+ gives ! greate/ am\nt ( /ability4 ,positives produc$ by a %ort exposure to light & subsequ5t developm5t ) ,gallic ,acid1 may be expect$ to be m p]man5t ?an ord9>y sun-pr9ts2 n t !re is any reason to suppose ! *emical composition ( a develop$ image to be peculi>1 b t ! use ( ! ,gallic ,acid enables u to increase ! int5sity ( ! r$ picture fir/ =m$1 & to add to its /ability by precipitat+ fre% ,silv] ^u x4 ,?is po9t has n always be5 att5d$ to4 ,x has be5 recomm5d$ to remove ! pr9t f ! develop+ solution :il/ 9 ! r$ & e>ly /age ( developm5t1 & to produce ! d>k tones subsequ5tly by means ( gold2 b ?is plan1 al?\gh giv+ v good results z reg>ds col\r & gradation ( tone1 appe>s to less5 ! advantage :i* w\ld o!rwise accrue f ! adoption ( a ,negative process1 & to leave ! picture1 z reg>ds p]man5cy1 mu* 9 ! condition ( an ord9>y pr9t obta9$ by direct action ( light4 ,! orig9al ,talbotype process1 9 :i* ! lat5t image is =m$ ^u ,iodide ( ,silv]1 produces1 next to ,collodion1 ! mo/ /able image2 b ! difficulty ( obta9+ bright & w>m t9ts on ,iodide ( ,silv]1 w /& 9 ! way ( its adoption4 ,! ton+ ( ,pap] ,positives is ! "p ( ! process :i* is likely to injure _! /ability2 inasmu* z ! f9e/ results _c easily be obta9$ )\t incurr+ sulphuration1 & ! action ( ,sulphur1 if c>ri$ to any ext5t1 has be5 %[n to be detrim5tal4 ,! po9t to be kept 9 view1 is to alt] ! orig9al /ructure ( ! image z little z possible 9 ton+2 & x is be/ to use ,gold 9 pref]5ce to ,sulphur z ! col\r+ ag5t4 ,on !oretical gr\nds1 ton+ by an alkal9e solution ( ,*loride ( ,gold 7p4 #acb71 & fix+ by ,ammonia1 is ! be/ process2 b ! employm5t ( ,sel d'or1 :i* gives a m agreeable col\r & has n be5 f\nd practically to injure ! image1 w be g5]ally pref]r$4 ,9 us+ a s+le fix+ & ton+ ,ba? ! same object ( work+ by ,gold r ?an by ,sulphur may be be/ atta9$ by ma9ta9+ ! activity ( ! ,ba? by con/ant additions ( ,*loride ( ,gold4 ,! pr9ts :i* are lea/ /able are su* z h be5 ton$ 9 acid ,hyposulphite ,ba?s1 )\t ,gold2 & ! difficulty ( pres]v+ su* pictures f becom+ yell[ 9 ! half-tones is v great4 ,possibly a portion ( ! ,sulphurett$ ,acid may unite ) ! ,suboxide ( ,silv] & _c be remov$ by wa%+ 7see p4 #aeh72 b ev5 if ?is be n ! case1 x is c]ta9 t no ord9>y am\nt ( c>e w obviate ! occasional occurr5ce ( fad+1 unless ! ,hyposulphite ,ba? be kept neutral to te/-pap]4 ,& all ^? plans ( ton+ 9 :i* ,acetic or ,hydro*loric ,acid is mix$ ) ,hyposulphite ( ,soda1 & ! ,positive imm]s$ :il/ ! liquid is 9 a milky /ate f precipitation ( ,sulphur1 ought /udi\sly to be avoid$4 ,x w be well also to avoid pu%+ ! action ( ! fix+ & ton+ ,ba? to its utmo/ limits1 s9ce practice & !ory bo? tea* u t ! ,positives :i* h be5 long 9 ! ,hyposulphite1 & consequ5tly %[ a t5d5cy to yell[ness 9 ! light p>ts1 are mo/ liable to lose _! half-tones on keep+4 ,photographic ,pr9ts are f\nd (t5 to d>k5 slightly 9 ! c\rse ( ye>s2 & !re=e by susp5d+ ! ton+ action at an e>li] /age a m>g9 is left = :at "s h t]m$ an improvem5t by "t4 ,! use ( ,album9iz$ 9 pref]5ce to pla9 pap] gives an advantage 9 protect+ ! image f oxidation2 b if con/antly expos$ to moi/ure1 a putrefactive decomposition ( ! animal matt] may occur4 ,! prop] col\r ( ! ,album5 image be+ a pale r$1 ! black tones %\ld n be s\ght = on t v>iety ( pap]3 _! production1 if ,hyposulphite ( ,soda 7 us$ 9 ton+1 w\ld probably imply an am\nt ( ,sulphuration :i* w\ld m ?an c\nt]balance any advantage o!rwise d]ivable f ! ,album54 ,p]man5t ,positives ( a black col\r may easily be obta9$ by s5sitiz+ pla9 pap]1 free f animal matt]s1 ) ,oxide ( ,silv] 9 place ( ,nitrate4 ,! simply fix$ image be+ 9 t case ( a sepia t9t1 requires a less am\nt ( ton+ to *ange x to black4 ,an impression 0 at "o "t preval5t t ,ammonio-,nitrate pr9ts 7 un/able2 b s f> f su* be+ ! case1 !y are prov$ to )/& ! action ( all de/ructive te/s bett] ?an pictures prep>$ ^u ! same k9d ( pap] s5sitiz$ ) pla9 ,nitrate ( ,silv]4 ,mode ( te/+ ! p]man5ce ( ,positives4--,! te/s = ,hyposulphite ( ,soda are n suffici5tly delicate to indicate ) c]ta9ty :5 ! process ( wa%+ has be5 prop]ly p]=m$4 ,! quantity ( t salt left 9 ! pap] is usually s small & s mu* mix$ up ) organic matt]1 t ! application ( ,protonitrate ( ,m]cury or ( ,nitrate ( ,silv] to ! liquid :i* dra9s f ! corn] ( ! pr9t1 w\ld probably mislead ! op]ator4 ,a dilute solution ( ,p]manganate ( ,pota%1 prep>$ by dissolv+ f half a gra9 or two gra9s ( ! salt1 accord+ to its purity1 9 "o gallon ( di/ill$ wat]1 af=ds a conv5i5t mode ( te/+ ,positives z reg>ds _! p[] ( resi/+ oxidation2 & to an exp]i5c$ eye x w prove ! pres5ce or abs5ce ( ,hyposulphite ( ,soda1 ! smalle/ trace ( :i* is suffici5t to remove ! p9k col\r ( ! ,p]manganate4 ,! mo/ available & simple plan ( te/+ p]man5ce is to enclose ! pictures 9 a /opp]$ glass bottle ) a small quantity ( wat]4 ,if !y reta9 _! half-tones aft] a c\rse ( ?ree mon?s ( ?is treatm5t1 & d n become m\ldy1 ! mode ( pr9t+ foll[$ is satisfactory4 ,boil+ wat] w also be f\nd useful 9 di/+ui%+ ! un/able col\rs produc$ by ,sulphur f ^? foll[+ ! judici\s employm5t ( ,gold2 9 all cases ! image w at fir/ be r$d5$ by ! hot wat]1 b if ton$ )\t ,sulphur x w1 z a rule1 recov] mu* ( its d>k col\r on dry+4 ,! *>act]i/ic appe>ance ( pr9ts :i* h be5 ,i mu* sulphurett$ 9 ! ton+ ,ba?1 & are v liable to fade1 %\ld be kn[n4 ,a yell[ col\r 9 ! lights is a bad sign2 & if ! half-tones are at all fa9t & indi/9ct1 ) an aspect ( comm5c+ yell[ness1 x is almo/ c]ta9 t ! ,positive w n la/ = any consid]able l5g? ( "t4 ,,*apt] ,,ix4 ,,on ,,! ,,!ory ,,( ,,! ,,dagu]reotype ,,& ,,talbotype ,,processes1 ,,etc4 ,,section ,i4 ,! ,dagu]reotype4 ,x 0 n ! orig9al int5tion ( ! ,au?or to include a description ( ! ,dagu]reotype ,process )9 ! limits ( ! pres5t ,"w4 ,! ,dagu]reotype is a bran* ( ! ,photographic ,art s di/9ct f ! o!rs1 t1 9 manipulatory details1 x be>s v little analogy to !m2 a slight sket* ( ! !ory ( ! process may n h[ev] be unacceptable4 ,all necess>y rem>ks w fall "u ?ree heads3--,! prep>ation ( ! ,dagu]reotype film2--! means by :i* ! lat5t image is develop$2--& ! /r5g!n+ ( ! image by ,hyposulphite ( ,gold4 ,! ,prep>ation ( ! ,dagu]reotype ,film4--,! s5sitive film ( ! ,dagu]reotypi/ is 9 _m respects diff]5t f t ( ! ,calotype or ,collodiotype4 ,! latt] may be t]m$ wet processes1 9 contradi/9ction to ! =m]1 :]e aque\s solutions are n employ$4 ,! ,dagu]reotype film is a pure & isolat$ ,iodide ( ,silv]1 =m$ by ! direct action ( ,iod9e ^u ! metal4 ,h5ce x lacks "o elem5t ( s5sitiv5ess possess$ by ! o!rs1 viz4 ! pres5ce ( soluble ,nitrate ( ,silv] 9 contact ) ! p>ticles ( ,iodide ( ,silv]4 ,x is important to rememb] t ! ,iodide ( ,silv] prep>$ by act+ ) vap\r ( ,iod9e ^u metallic ,silv]1 is diff]5t 9 its ,photographic action f ! yell[ salt obta9$ by d\ble decomposition betwe5 ,iodide ( ,potassium & ,nitrate ( ,silv]4 ,a ,dagu]reotype film1 :5 expos$ to a bright light1 fir/ d>k5s to an a%-grey col\r & !n becomes ne>ly :ite2 ! solubility 9 ,hyposulphite ( ,soda be+ at ! same "t less5$4 ,a ,collodion film1 on ! o!r h&1 if ! excess ( ,nitrate ( ,silv] be wa%$ (f1 al?\gh x is /ill capable ( receiv+ ! radiant impression 9 ! ,cam]a1 does n alt] ei!r 9 col\r or 9 solubility1 by exposure ev5 to ! sun's rays4 ,details ( ! process = prep>+ a ,dagu]reotype ,plate4--,a copp] plate ( mod]ate ?ickness is coat$ ^u ! surface ) a lay] ( pure ,silv]1 ei!r by ! electrotype or 9 any o!r conv5i5t mann]4 ,x is !n poli%$ ) great c>e1 until ! surface assumes a brilliant metallic lu/re4 ,?is prelim9>y op]ation ( poli%+ is "o ( great practical importance1 & ! tr\blesome details att5d+ x con/itute "o ( ! ma9 difficulties to be ov]come4 ,aft] ! poli%+ is complete1 ! plate is ready to receive ! s5sitive coat+4 ,?is "p ( ! process is conduct$ 9 a peculi> mann]4 ,a simple piece ( c>dbo>d or a ?9 %eet ( wood1 previ\sly soak$ 9 solution ( ,iod9e1 evolves en\gh ( ! vap\r to attack ! silv] plate2 :i* be+ plac$ imm$iately above1 & all[$ to rema9 = a %ort "t1 acquires a pale violet hue1 due to ! =mation ( an excessively delicate lay] ( ,iodide ( ,silv]4 ,by prolong+ ! action ( ! ,iod9e ! violet t9t disappe>s & a v>iety ( prismatic col\rs are produc$1 mu* 9 ! same way z :5 light is decompos$ by ?9 plates ( mica or ! surface ( "m-(-pe>l4 ,f violet ! plate becomes ( a /raw-yell[1 !n rose-col\r1 & aft]w>ds /eel-grey4 ,by cont9u+ ! exposure1 ! same sequ5ce ( t9ts is repeat$2 ! /eel-grey disappe>s1 & ! yell[ & rose-col\rs recur4 ,! deposit ( ,iodide ( ,silv] gradually increases 9 ?ickness dur+ ^! *anges2 b to ! end x rema9s excessively ?9 & delicate4 ,9 ?is respect x contra/s /rongly ) ! d5se & creamy lay] (t5 employ$ 9 ! ,collodion process1 & %[s t a l>ge proportion ( ! ,iodide ( ,silv] mu/ 9 su* a case be sup]flu\s1 z f> z any influ5ce produc$ by ! light is conc]n$4 ,an inspection ( a s5sitive ,dagu]reotype plate reveals ! microscopic nature ( ! act9ic *anges involv$ 9 ! ,photographic ,art1 & tea*es a useful lesson4 ,increase ( s5sibility obta9$ by comb9+ ! jo9t action ( ,brom9e & ,iod9e4--,! orig9al process ( ,dagu]re 0 conduct$ ) ! vap\r ( ,iod9e only2 b 9 ! ye> #ahdj x 0 discov]$ by ,mr4 ,john ,godd>d t ! s5sibility ( ! plate 0 greatly promot$ by expos+ x to ! vap\rs ( ,iod9e & ,brom9e 9 succession1--! prop] "t = ea* be+ regulat$ by ! t9ts assum$4 ,! composition ( ?is ,bromo-,iodide ( ,silv]1 s call$1 is unc]ta91 & has n be5 prov$ to be> any analogy to t ( ! mix$ salt obta9$ by decompos+ a solution ( ,iodide & ,bromide ( ,potassium ) ,nitrate ( ,silv]4 ,obs]ve also t ! ,bromo-,iodide ( ,silv] is m s5sitive ?an ! simple ,iodide only tok5 ! vap\r ( ,m]cury is employ$ z a develop]4 ,m4 ,claudet proves t if ! image be =m$ by ! direct action ( light alone 7see page #agd71 ! usual condition is rev]s$1 & t ! use ( ,brom9e "u su* circum/ances ret>ds ! effect4 ,! ,developm5t & ,prop]ties ( ! ,image4--,! lat5t image ( ! ,dagu]reotype is develop$ 9 a mann] diff]5t f t ( ! humid processes g5]ally1--viz4 by ! action ( ,m]curial vap\r4 ,m]cury1 or ,quicksilv]1 is a metallic fluid :i* boils at #ffb ,fahr5heit4 ,we are n h[ev] to suppose t ! iodiz$ plate is subject$ to ! vap\r ( ,m]cury at a temp]ature at all approa*+ to #ffb4 ,! cup conta9+ ! ,quicksilv] is previ\sly heat$ by means ( a _s-lamp to ab\t #adj1 a temp]ature easily borne by ! h&1 9 mo/ cases1 )\t inconv5i5ce4 ,! am\nt ( ,m]curial vap\r evolv$ at #adj is v small1 b x is suffici5t = ! purpose1 & aft] cont9u+ ! action = a %ort "t ! image is p]fectly develop$4 ,!re are few que/ions :i* h giv5 rise to great] discussion among/ *emi/s ?an ! nature ( ! ,dagu]reotype image4 ,un=tunately1 ! quantity ( mat]ial to be op]at$ on is s small1 t x becomes almo/ impossible to asc]ta9 its composition by direct analysis4 ,"s suppose x to consi/ ( ,m]cury alone4 ,o!rs h ?\ght t ! ,m]cury is 9 comb9ation ) metallic ,silv]4 ,! pres5ce ( ! =m] metal is c]ta91 s9ce ,m4 ,claudet %[s t1 by ! application ( a /rong heat1 x c actually be volatiliz$ f ! image 9 suffici5t quantity to develope a second impression imm$iately sup]impos$4 ,x is a rem>kable fact t an image m or less resembl+ t develop$ by ,m]cury c be obta9$ by ! prolong$ action ( light alone ^u ! iodiz$ plate4 ,! sub/ance s =m$ is a :ite p[d]1 insoluble 9 solution ( ,hyposulphite ( ,soda2 amorph\s to ! eye1 b pres5t+ ! appe>ance ( m9ute reflect+ cry/als :5 highly magnifi$4 ,its composition is unc]ta94 ,= all practical purposes ! production ( ! ,dagu]reotype image by light alone is useless1 on acc\nt ( ! l5g? ( "t requir$ to effect x4 ,?is 0 allud$ to 9 ! ?ird ,*apt]1 :]e x 0 %[n t 9 ! case ( ! ,bromo-,iodide ( ,silv] an int5sity ( light #cjjj times great] is requir$1 if ! use ( ! ,m]curial vap\r be omitt$4 ,m4 ,ed4 ,becqu]el's discov]y ( ! cont9u+ action ( rays ( yell[ light4--,pure homog5e\s yell[ light has no action ^u ! ,dagu]reotype plate2 b if ! iodiz$ surface be fir/ expos$ to :ite light = a suffici5t "t to impress a lat5t image1 & !n aft]w>ds to ! yell[ light1 ! action already comm5c$ is cont9u$1 & ev5 to ! ext5t ( =m+ ! peculi> :ite deposit1 insoluble 9 ,hyposulphite ( ,soda1 already allud$ to4 ,yell[ light may !re=e 9 ?is s5se be spok5 ( z a develop+ ag5t1 s9ce x produces ! same effect z ! ,m]curial vap\r 9 br++ out to view ! lat5t image4 ,a s+ul> anomaly h[ev] requires notice1 viz4 t if ! plate be prep>$ ) ! mix$ vap\rs ( ,brom9e & ,iod9e1 9 place ( ,iod9e alone1 !n ! yell[ light _c be made to develope ! image4 ,9 fact1 ! same col\r$ ray :i* cont9ues ! action ( :ite light ^u a surface ( ,iodide ( ,silv]1 actually de/roys x1 & re/ores ! p>ticles to _! orig9al condition1 ) a surface ( ,bromo-,iodide ( ,silv]4 ,^! facts1 al?\gh n ( great practical importance1 are int]e/+ 9 illu/ration ( ! delicate & complex nature ( ! *emical *anges produc$ by light4 ,! ,/r5g!n+ ( ! ,dagu]reotype ,image by means ( ,hyposulphite ( ,gold4--,! use ( ! ,hyposulphite ( ,gold to :it5 ! ,dagu]reotype image1 & r5d] x m la/+ & inde/ructible1 0 introduc$ by ,m4 ,fizeau1 subsequ5t to ! orig9al discov]y ( ! process4 ,aft] removal ( ! unalt]$ ,iodide ( ,silv] by means ( ,hyposulphite ( ,soda1 ! plate is plac$ ^u a levell+ /& & cov]$ ) a solution ( ,hyposulphite ( ,gold1 conta9+ ab\t "o "p ( ! salt dissolv$ 9 #ejj p>ts ( wat]4 ,! flame ( a _s-lamp is !n appli$ until ! liquid beg9s to boil4 ,%ortly a *ange is se5 to take place 9 ! appe>ance ( ! image2 x becomes :it] ?an be=e1 & acquires great =ce4 ,?is fact seems to prove conclusively t metallic ,m]cury ent]s into its composition1 s9ce a surface ( ,silv]--su*1 = in/ance1 z t ( ! ,collodion image--is d>k5$ by ,hyposulphite ( ,gold4 ,! diff]5ce 9 ! action ( ! gild+ solution ^u ! image & ! pure ,silv] surr\nd+ x illu/rates ! same fact4 ,?is ,silv]1 :i* appe>s ( a d>k col\r1 & =ms ! %ad[s ( ! image1 is r5d]$ /ill d>k]2 a v delicate cru/ ( metallic ,gold gradually =m+ ^u x1 :]eas ) ! image ! :it5+ effect is imm$iate & /rik+4 ,,section ,,ii4 ,!ory ( ! ,talbotype & ,album5 ,processes4 ,! ,talbotype or ,calotype4--,?is process1 z practic$ by _m at ! pres5t "t1 is almo/ id5tical ) t orig9ally describ$ by ,mr4 ,fox ,talbot4 ,! object is to obta9 an ev5 & f9ely divid$ lay] ( ,iodide ( ,silv] ^u ! surface ( a %eet ( pap]2 ! p>ticles ( ! ,iodide be+ left 9 contact ) an excess ( ,nitrate ( ,silv]1 & usually ) a small proportion ( ,gallic ,acid1 to height51 /ill fur!r1 ! s5sibility to light4 ,! ,engli% pap]s siz$ ) ,gelat9e are commonly us$ = ! ,calotype process2 !y reta9 ! film m p]fectly at ! surface1 & ! ,gelat9e 9 all probability assi/s 9 =m+ ! image4 ,) a =eign />*-pap]1 unless x be re-siz$ ) "s organic sub/ance1 ! solutions s9k 9 too deeply1 & ! picture is want+ 9 cle>ness & def9ition4 ,!re are two modes ( iodiz+ & s5sitiz+ ! %eets3 fir/1 by float+ alt]nately ^u ,iodide ( ,potassium & ,nitrate ( ,silv]1 9 ! same mann] z 9 ! prep>ation ( pap]s = ,positive ,pr9t+2 & second1 by :at is t]m$ ! s+le wa%1 :i* is ?\ght by _m to give sup]ior results z reg>ds s5sitiv5ess & int5sity ( image4 ,to iodize by ?is mode1 ! yell[ ,iodide ( ,silv]1 prep>$ by mix+ solutions ( ,iodide ( ,potassium & ,nitrate ( ,silv]1 is dissolv$ 9 a /rong solution ( ,iodide ( ,potassium2 ! %eets are float$ = an in/ant ^u ?is liquid & dri$2 !y are !n remov$ to a di% ( wat]1 by ! action ( :i* ! ,iodide ( ,silv] is precipitat$ ^u ! surface ( ! pap] 9 a f9ely divid$ /ate4 ,! prop]ties ( a solution ( ,iodide ( ,silv] 9 ,iodide ( ,potassium1 or ( ! d\ble ,iodide ( ,potassium & ,silv]1 are describ$ at page #dc1 a ref]5ce to :i* w %[ t ! d\ble salt is decompos$ by a l>ge quantity ( wat]1 ) precipitation ( ! ,iodide ( ,silv]1 ?is sub/ance be+ insoluble 9 a dilute solution ( ,iodide ( ,potassium1 al?\gh soluble 9 a /rong solution4 ,pap] coat$ ) ,iodide ( ,silv] by ?is mode1 aft] prop] wa%+ 9 wat] to remove soluble salts 7:i* if all[$ to rema9 w\ld attract damp71 w keep good = a long "t4 ,! lay] ( ,iodide appe>s ( a pale primrose col\r1 & is p]fectly ins5sitive to light4 ,ev5 exposure to ! sun's rays produces no *ange1 ?us indicat+ t an excess ( ,nitrate ( ,silv] is ess5tial to ! visible d>k5+ ( ,iodide ( ,silv] by light4 ,! pap] is also ins5sitive to ! reception ( an invisible image1 diff]+ 9 ?is respect f ! wa%$ ,collodion plate1 :i* receives an impression 9 ! ,cam]a1 al?\gh app>5tly fre$ f ,nitrate ( ,silv]4 ,to r5d] ,calotype pap] s5sitive to light1 x is bru%$ ) a solution ( ,nitrate ( ,silv] conta9+ bo? ,acetic & ,gallic ,acids1 t]m$ ,aceto-,nitrate & ,gallo-,nitrate solution4 ,! ,gallic ,acid less5s ! keep+ qualities ( ! pap]1 b increases ! s5sitiv5ess4 ,! ,acetic ,acid prev5ts ! pap] f black5+ all ov] dur+ ! developm5t1 & pres]ves ! cle>ness ( ! :ite p>ts2 its employm5t is indisp5sable4 ,! pap] is commonly excit$ ^u ! morn+ ( ! day ^u :i* x is int5d$ to be us$2 & ! long] x is kept1 ! less active & c]ta9 x becomes4 ,an exposure ( five to eight m9utes 9 ! ,cam]a is ! av]age "t ) an ord9>y view l5s4 ,! picture is develop$ ) a saturat$ solution ( ,gallic ,acid1 to :i* a portion ( ,aceto-,nitrate ( ,silv] is add$ to height5 ! int5sity4 ,bo? ,sulphate ( ,iron1 & ,pyrogallic ,acid h also be5 us$1 b !y are unnecess>ily /rong1 ! invisible image be+ m easily develop$ ^u pap] ?an ^u ,collodion 7see page #adc74 ,aft] fix+ ! ,negative by remov+ ! unalt]$ ,iodide ( ,silv] ) ,hyposulphite ( ,soda1 x is well wa%$ & dri$4 ,:ite wax is !n melt$ 9 ) a hot iron1 s z to r5d] ! pap] transp>5t1 & to facilitate ! aft]-process ( pr9t+4 ,! ,calotype _c be comp>$ ) ! ,collodion process = s5sitiv5ess & delicacy ( detail1 b x possesses advantages = t\ri/s & ^? :o d n wi% to be encumb]$ ) l>ge glass plates4 ,! pr9cipal difficulty appe>s to be 9 obta9+ a uni=mly good pap]1 _m samples giv+ a speckl$ appe>ance 9 ! black p>ts ( ! ,negative4 ,! ,wax$ ,pap] process ( ,le ,grey4--,?is is a useful modification ( ! ,talbotype introduc$ by ,m4 ,le ,grey4 ,! pap] is wax$ be=e iodiz+1 by :i*1 )\t involv+ any additional op]ation1 a v f9e surface lay] ( ,iodide ( ,silv] c be obta9$4 ,! ,wax$ ,pap] ,process is well adapt$ = t\ri/s1 f its extreme simplicity & ! l5g? ( "t :i* ! film may be kept 9 a s5sitive condition4 ,bo? ,engli% & =eign pap]s are employ$3 b ! =m] take ! wax ) difficulty4 ,mr4 ,crookes1 :o has devot$ 8 att5tion to ?is process1 gives cle> directions = wax+ pap]2 x is ess5tial t pure :ite wax %\ld be obta9$ direct f ! blea*]s1 s9ce ! flat cakes sold 9 ! %ops are commonly adult]at$4 ,! temp]ature mu/ also be c>efully kept bel[ t po9t at :i* decomposition ( ! wax takes place2 ! use ( too hot an iron be+ a common s\rce ( failure 7see ',photographic ,j\rnal1' vol4 ii4 p4 #bca74 ,! %eets ( pap]1 hav+ be5 prop]ly wax$1 are soak$ = two h\rs 9 a solution conta9+ ,iodide & ,bromide ( ,potassium1 )1 en\gh free ,iod9e to t+e ! liquid ( a port-w9e col\r4 ,! greasy nature ( wax imp$es ! entry ( liquids1 & h5ce a long imm]sion is requir$4 ,! iodiz+ =mul ( ! ,fr5* ,photograph]s h be5 encumb]$ by ! addition ( a v>iety ( sub/ances :i* appe> to introduce complications )\t giv+ proportional advantage1 & ,mr4 ,t[n%5d has done ! art a s]vice by prov+ t ! ,iodide & ,bromide ( ,potassium1 ) free ,iod9e1 are suffici5t4 ,?is latt] +r$i5t 0 fir/ us$ by ,mr4 ,crookes2 x seems to add to ! cle>ness & %>pness ( ! ,negatives2 & z ! pap]s are col\r$ by ! ,iod9e1 air-bubbles _c escape detection4 ,! process ( excit+ ) ,nitrate ( ,silv] is also r5d]$ m c]ta9 by ! employm5t ( free ,iod9e1 ! action ( ! ,ba? be+ cont9u$ until ! purple col\r gives place to ! *>act]i/ic yell[ t9t ( ! ,iodide ( ,silv]4 ,wax$ ,pap] is r5d]$ s5sitive by imm]sion 9 a ,ba? ( ,nitrate ( ,silv] conta9+ ,acetic ,acid2 ! quantity ( :i* latt] +r$i5t %\ld be increas$ :5 ! pap]s are to be long kept4 ,z ! excess ( ,nitrate is subsequ5tly remov$1 ! solution may be us$ weak] ?an 9 ! ,calotype or ,collodion process4 ,aft] excit+1 ! pap]s are wa%$ ) wat] to r$uce ! am\nt ( free ,nitrate ( ,silv] to a m9imum4 ,?is less5s ! s5sitiv5ess1 b greatly increases ! keep+ qualities1 & ! pap] w (t5 rema9 good = t5 days or long]4 ,x is a v important po9t1 9 op]at+ ) ,wax$ ,pap]1 to keep ! develop+ di%es clean4 ,! developm5t is conduct$ by imm]sion 9 a ,ba? ( ,gallic ,acid conta9+ ,acetic ,acid & ,nitrate ( ,silv]2 & be+ ret>d$ by ! sup]ficial coat+ ( wax1 !re is always a t5d5cy to an irregul> r$uction ( ,silv] ^u ! :ite portions ( ! ,negative4 ,:5 ! develop] becomes br[n & discol\r$1 ?is is almo/ sure to happ52 & x is well kn[n to *emi/s t ! l5g? ( "t dur+ :i* ,gallic ,acid & ,nitrate ( ,silv] may rema9 mix$ )\t decompos+1 is mu* less5$ by us+ vessels :i* are dirty f hav+ be5 be=e employ$ = a simil> purpose4 ,! black deposit ( ,silv] ex]cises a catalytic 71 decomposition by contact7 action ^u ! fre%ly-mix$ portion1 & ha/5s its discoloration4 ,! ,wax$ ,pap] process is exce$+ly simple & inexp5sive1--v suitable = t\ri/s1 z requir+ b little exp]i5ce1 & a m9imum ( app>atus4 ,x is h[ev] sl[ & t$i\s 9 all its /ages1 ! s5sitive pap]s frequ5tly tak+ an exposure ( tw5ty m9utes 9 ! ,cam]a1 & ! developm5t ext5d+ ov] an h\r or an h\r & a half4 ,sev]al ,negatives h[ev] may be develop$ at ! same "t2 & z ! removal ( ! free ,nitrate ( ,silv] gives ! process a great advantage dur+ hot wea!r1 x w 9 all probability cont9ue to be ext5sively foll[$4 ,! pr9ts :i* h be5 s5t to ! ,exhibition ( ! ,photographic ,society1 %[ t wax$ pap] 9 ! h&s ( a skilful op]ator may be made to del9eate ar*itectural subjects ) great fidelity1 & also to give ! details ( foliage & l&scape ,photography ) di/9ctness4 ,! ,album5 process ^u ,glass4--,! process ) ,album5 orig9at$ 9 a desire to obta9 a m ev5 surface lay] ( ,iodide ( ,silv] ?an ! co>se /ructure ( ! tissue ( pap] w all[4 ,x is conduct$ ) simple ,album51 or :ite ( eggs1 dilut$ ) a conv5i5t quantity ( wat]4 ,9 ?is glut9\s liquid ,iodide ( ,potassium is dissolv$2 & ! solution1 hav+ be5 ?or\ghly %ak51 is set aside1 ! upp] portion be+ drawn (f = use1 9 ! same mann] z 9 ! prep>ation ( ,album9iz$ pap] = pr9t+4 ,! glasses are coat$ ) ! ,iodiz$ ,album51 & are !n plac$ horizontally 9 a box to dry4 ,?is "p ( ! process is consid]$ ! mo/ tr\blesome1 ! moi/ ,album5 easily attract+ p>ticles ( du/1 & be+ apt to bli/] & sep>ate f ! glass4 ,if an ev5 lay] ( ! dri$ & ,iodiz$ mat]ial c be obta9$1 ! *ief difficulty ( ! process has be5 ov]come4 ,! plates are r5d]$ s5sitive by imm]sion 9 a ,ba? ( ,nitrate ( ,silv] ) ,acetic ,acid add$1 & are !n wa%$ 9 wat] & dri$4 ,!y may be kept = a long "t 9 an excit$ /ate4 ,! exposure 9 ! ,cam]a mu/ be unusually long2 ! free ,nitrate ( ,silv] hav+ be5 remov$ by wa%+1 & ! ,album5 ex]cis+ a direct ret>d+ influ5ce ^u ! s5sitiv5ess ( ,iodide ( ,silv]4 ,! developm5t is conduct$ 9 ! ord9>y way by a mixture ( ,gallic ,acid & ,nitrate ( ,silv]1 ) ,acetic ,acid add$ to pres]ve ! cle>ness ( ! lights4 ,x usually requires "o h\r or m1 b may be accel]at$ by ! g5tle application ( heat4 ,album5 pictures are rem>kable = elaborate di/9ctness 9 ! %ad[s & m9or details1 & are admirably adapt$ = view+ 9 ! ,/]eoscope2 b !y d n (t5 possess ! peculi> & *>act]i/ic s(tness ( ! ,photograph ^u ,collodion4 ,! process is well adapt$ = hot climates1 be+ v little prone to ! cl\d9ess & irregul> r$uction ( ,silv] :i* are (t5 compla9$ ( ) moi/ ,collodion "u su* circum/ances4 ,m4 ,taup5ot's ,collodio-,album5 process4--,?is is a rec5t discov]y :i* seems to involve a new pr9ciple 9 ! ,art1 & gives promise ( great utility4 ,"o ( ! greate/ objections to ! ,album5 process has be5 its want ( s5sitiv5ess2 b ,m4 ,taup5ot f\nd t ?is 0 obviat$ to a great ext5t by p\r+ ! ,album5 ^u a plate previ\sly coat$ ) ,iodide ( ,silv]4 ,9 ?is way two lay]s ( t s5sitive salt are =m$1 & ! s5sibility ( ! surface lay]1 :i* alone receives ! image1 is promot$ by its re/+ ^u a sub/ratum ( ,iodide r ?an ^u ! in]t surface ( ! glass4 ,9 ?is view1 if ! !ory be correct1 ! l[] p>ticle ( ,iodide ( ,silv] promotes ! molecul> di/urbance ( ! upp]1 itself rema9+ un*ang$4 ,o!r exp]im5t]s1 pursu+ ! subject fur!r1 h ass]t$ t a successful result may be obta9$ by coat+ ! plate ) pla9 ,collodion & subsequ5tly ) ,iodiz$ ,album54 ,if ?is obs]vation %\ld prove correct1 ! process w be simplifi$ & its utility increas$4 ,9 ! six? ,*apt] ( ,"p ,,ii4 ! practical details ( ! ,collodio-,album5 process w be describ$4 ,,end ,,( ,,"p ,i4 ,,"p ,,ii4 ,,practical ,,details ,,( ,,! ,,collodion ,,process4 ,,practical ,,details ,,( ,,! ,,collodion ,,process4 ,illu/ration ,,*apt] ,i4 ,,prep>ation ,,( ,,collodion4 ,?is includes--! soluble ,pap]2--! ,alcohol & ,e!r2--& ! iodiz+ comp\nds4 ,! =mul = ,negative & ,positive ,collodion1 & = ! ,nitrate ,ba? & develop+ fluids1 are giv5 9 ! second ,*apt]4 ,,! ,,soluble ,,pap]4 ,pyroxyl9e may be prep>$ ei!r f cotton wool or f ,sw$i% ,filt]+-pap]4 ,mo/ op]ators pref] ! latt]1 f its giv+ a product ( con/ant solubility1 & yield+ a fluid solution4#cj ,! ,cotton ,wool h[ev] is bett] adapt$ = use ) ! ,sulphuric ,acid & ,nitre1 s9ce ! ,pap]1 f its clos5ess ( texture1 requires a long] imm]sion 9 ! mixture4 #cj ,sw$i% filt]+-pap] may be procur$ at ! op]ative *emi/s'1 at ab\t five %ill+s ! quire4 ,ea* half-%eet has ! wat]-m>k ,j4 ,h4 ,munktell4 ,prep>ation ( a ,nitro-,sulphuric ,acid ( ! prop] /r5g?4--,!re are two modes ( prep>+ ! ,nitro-,sulphuric ,acid3 fir/1 by mix+ ! acids2 second1 by ! ,oil ( ,vitriol & ,nitre ,process4 ,! =m] is ! be/ 9 cases :]e l>ge quantities ( ! mat]ial are op]at$ on1 b ! amateur is recomm5d$ to beg9 by try+ ! ,nitre ,process 7p4 #aij7 z ! mo/ simple4 ,,prep>ation ,,( ,,nitro-,,sulphuric ,,acid ,,by ,,! ,,mix$ ,,acids4 ,! op]ator may proce$ 9 ei!r ( two ways2 fir/1 by tak+ ! /r5g? ( ea* sample ( acid1 & mix+ accord+ to fix$ rule2 second1 by a m ready plan1 :i* may be us$ :5 ! exact /r5g? ( ! acids is n kn[n4 ,ea* ( ^! w be describ$ 9 succession4 a4 ,directions = mix+ accord+ to fix$ rule4--,?is process is giv5 f ,mr4 ,had['s orig9al pap] 9 ! ',qu>t]ly ,j\rnal ( ! ,*emical ,society4' ,x is c]ta9 9 its results if ! /r5g? ( bo? acids be accurately det]m9$4 ,a v p]fect process = tak+ ! /r5g? ( ,nitric ,acid is by means ( p[d]$ ,m>ble or ,c>bonate ( ,lime1 z describ$ 9 v>i\s works on practical ,*emi/ry4 ,sulphuric ,acid may be e/imat$ by precipitat+ ) ,nitrate ( ,b>yta1 & weigh+ ! insoluble ,sulphate ) ! prop] precautions4 ,! specific gravity is n a crit]ion ( /r5g? to be p]fectly reli$ on1 b if x be adopt$ z a te/1 ! foll[+ po9ts mu/ be att5d$ to4 #a/4 ,t ! temp]ature ( ! acid be at or ne> #fj ,fahr5heit2 ! d5sity ( ,sulphuric ,acid especially is1 f its small specific heat1 greatly influ5c$ a *ange ( temp]ature4 #bnd4 ,! sample ( ,nitric ,acid mu/ be free f ,p]oxide ( ,nitrog51 or only slightly col\r$ by x4 ,?is sub/ance1 :5 pres5t1 increases ! specific gravity ( ! acid )\t add+ to its available prop]ties4 ,a yell[ sample ( ,nitric ,acid w !re=e be some:at weak] ?an is indicat$ by ! specific gravity4 #crd4 ,! ,oil ( ,vitriol %\ld yield no solid residue on evaporation4 ,sulphate ( ,lead & ,bisulphate ( ,pota% are (t5 f\nd 9 ! comm]cial acid1 & add mu* to its d5sity4 ,oil ( ,vitriol conta9+ ,sulphate ( ,lead becomes milky on dilution4 ,! =mula = a def9ite ,nitro-,sulphuric ,acid1 ( ! prop] /r5g? = mak+ ! soluble ,pyroxyl9e1 may be /at$ ?us3-- ,,ho ,,no#e1 #b 7,,ho ,,s#c7 #c-a_/b ,,ho or ,atoms4 ,atomic weight4 ,nitric ,acid #a #ed ,sulphuric ,acid #b #hj ,wat] #f-a_/b #eh --- #aib ,hav+ f\nd ! p]c5tage ( real acid :i* is pres5t1#ca ! foll[+ calculation w give ! relative weights ( ! +r$i5ts requir$ to produce ! =mula3-- ,let a p]c5tage ( real ,nitric ,acid1 b ,sulphuric ,acid1 !n #edjj_/;a quantity ( ,nitric ,acid1 #hjjj_/;b ,sulphuric ,acid1 #aib - #edjj_/;a - #hjjj_/;b ,wat]4 #ca ,tables are giv5 9 ! ,app5dix = calculation by specific gravity2 b direct analysis ( ! acids is ! mo/ c]ta94 ,obs]ve t ! numb]s 9 ! calculation correspond to ! atomic weights rec5tly giv52 & t ! am\nt ( wat] is d]iv$ f ! total atomic weight1 viz4 #aib1 m9us ! sum ( ! weights ( bo? acids4 ,h5ce if ! samples ( acid employ$ are too weak = ! purpose1 ! =mula = ! wat] gives a negative quantity4 ,! weight ( mix$ acids produc$ by ! =mula is #aib gra9s1 :i* w\ld measure some:]e ab\t two fluid dra*ms4 ,t5 times ?is quantity =ms a conv5i5t bulk ( liquid1 9 :i* ab\t #ej or #fj gra9s ( ,pap] may be imm]s$4 ,9 weigh+ corrosive liquids1 su* z ,sulphuric & ,nitric ,acid1 a small glass may be c\nt]balanc$ 9 ! scale-pan1 & ! acid p\r$ 9 c>efully4 ,if too mu* is add$1 ! excess c be remov$ by a glass rod1 or by ! pipette commonly employ$ = su* a purpose4 ,! foll[+ example ( a calculation simil> to ! above may be giv53-- #ajj p>ts ( ! ,oil ( ,vitriol #gffe real acid4 ,nitric ,acid #fed real acid4 !re=e #hjjj_/gffe #ajdc gra9s ( ,oil ( ,vitriol4 #edjj_/fed #hbe ,nitric ,acid #aib - #ajdc - #hbe #eb ,wat]4 ,multiply+ ^! weights t5 times1 we h ,oil ( ,vitriol #ajdc gra9s4 ,nitric ,acid #hbe ,wat] #eb ---- ,total weight ( ! #aibj gra9s4 ,nitro-,sulphuric ,acid ,hav+ prep>$ ! acid mixture ( a def9ite /r5g? by ! above =mula1 ! pap] mu/ be imm]s$ accord+ to directions giv5 at page #aia4 b4 ,process = mix+ ,nitro-,sulphuric ,acid1 ! /r5g? ( ! two acids n hav+ be5 previ\sly det]m9$4--,take a /rong sample ( ,nitric ,acid 7! yell[ ,nitr\s acid1 s call$1 succe$s well71 & mix x ) ,oil ( ,vitriol z foll[s3-- ,sulphuric ,acid #aj fluid dra*ms1 ,nitric ,acid #aj ,n[ imm]se a !rmomet] & note ! temp]ature2#cb x %\ld be f #acj ,fahr4 to #aej4 ,if x s9ks bel[ #abj1 place ! mixture 9 a capsule1 & float ^u boil+ wat] = a few m9utes4 #cb ,9 ! prep>ation ( soluble cotton1 & inde$ 9 all ,photographic manipulations1 a !rmomet] is almo/ indisp5sable4 ,in/rum5ts ( suffici5t delicacy = common purposes are sold 9 ,hatton ,g>d5 & else:]e1 at a l[ price4 ,! bulb %\ld be uncov]$1 to admit ( be+ dipp$ 9 acids1 etc41 )\t injury to ! scale4 ,a prelim9>y exp]im5t ) a small tuft ( ,cotton ,wool 7cotton %[s x bett] ?an pap]7 w !n indicate ! actual /r5g? ( ! ,nitro-,sulphuric ,acid4 ,/ir ! tuft 9 ! mixture = five m9utes4 ,remove ) a glass rod1 & wa% ) wat] = a %ort "t1 until no acid ta/e c be p]ceiv$4 ,if ! ,wool becomes matt$1 & gelat9izes slightly on its fir/ imm]sion 9 ! acid1 or if1 9 ! subsequ5t wa%+1 ! fibres appe> to adh]e & to be dis9tegrat$ by ! action ( ! wat]1 ! ,nitro-,sulphuric ,acid is too weak4 ,9 t case add to ! acid mixture4 ,oil ( ,vitriol1 #c dra*ms4 ,if ! cotton 0 actually dissolv$ 9 ! fir/ trial1 an addition ( half ( a fluid ounce ( ,oil ( ,vitriol may be requir$4 ,suppos+ ! cotton n to be gelat9iz$ & to wa% well1 !n wr+ x out v dry1 pull out ! fibres1 & treat x 9 a te/-tube ) rectifi$ ,e!r1#cc to :i* a few drops ( ,alcohol h be5 add$4 ,if x be insoluble1 dry x by a g5tle heat & apply a flame3 a brisk explosion indicates t ! ,nitro-,sulphuric ,acid employ$ is too /rong4 ,9 t case1 add to ! tw5ty dra*ms ( mix$ acids1 "o dra*m ( wat]1 & te/ aga91 repeat+ ! process until a soluble product is obta9$4 #cc ,obs]ve t ! ,e!r be pure2 if x conta9s too mu* wat] & ,alcohol1 x w n dissolve ! ,pyroxyl9e1 or w yield an opalesc5t solution4 ,!re is a ?ird condition ( ,pyroxyl9e1 diff]5t f ei!r ( ! above1 :i* may be puzzl+3--! fibres ( ! ,cotton mat toge!r v slightly or n at all on imm]sion1 & ! wa%+ proce$s tol]ably well2 ! comp\nd =m$ is sc>cely explosive1 & dissolves imp]fectly 9 ,e!r1 leav+ little nodules or h>d lumps4 ,! e!real solution yields1 on evaporation1 a film :i* is opaque in/ead ( transp>5t4 ,9 ?is case 7presum+ ! ,e!r to be good7 ! acid mixture is slightly too weak1 or ! temp]ature is too l[1 be+ probably ab\t #ij1 in/ead ( #acj to #adj 7874 ,:5 ! acid mixture has be5 br\ght to ! prop] /r5g? by a few prelim9>y trials1 proce$ accord+ to ! directions giv5 at ! next page4 ,,prep>ation ,,( ,,nitro-,,sulphuric ,,acid ,,by ,,oil ,,( ,,vitriol ,,& ,,nitre4 ,?is process is recomm5d$1 9 pref]5ce to ! o!r1 to ! amateur :o is unable to obta9 ,nitric ,acid ( conv5i5t /r5g?4 ,! common ,oil ( ,vitriol sold 9 ! %ops is (t5 v good = ,photographic purposes2 b x is be/1 if possible1 to take ! specific gravity1 :5 any d\bt exi/s ( its g5u95ess4 ,at a temp]ature ( #eh to #fj1 specific gravity #ahcc is ! usual /r5g?1 & if x falls bel[ ?is1 x %\ld be reject$4 7,see ,"p ,,iii4 = ',impurities ( ,comm]cial ,sulphuric ,acid4'7 ,! ,nitre mu/ be ! pure/ sample :i* c be obta9$4 ,comm]cial ,nitre (t5 conta9s a l>ge quantity ( ,*loride ( ,potassium1 detect$ on dissolv+ ! ,nitre 9 di/ill$ wat]1 & add+ a drop or two ( solution ( ,nitrate ( ,silv]4 ,if a milk9ess & subsequ5t curdy deposit is =m$4 ,*lorides are pres5t4 ,^! ,*lorides are injuri\s2 aft] ! ,oil ( ,vitriol is add$1 !y de/roy a portion ( ,nitric ,acid by conv]t+ x into br[n fumes ( ,p]oxide ( ,nitrog51 & s alt] ! /r5g? ( ! solution4 ,nitrate ( ,pota% is an anhydr\s salt1--x conta9s simply ,nitric ,acid & ,pota%1 )\t any wat] ( cry/allization2 /ill1 9 _m cases1 a little wat] is reta9$ me*anically betwe5 ! int]/ices ( ! cry/als1 & !re=e x is bett] to dry x be=e use4 ,?is may be done by lay+ x 9 a /ate ( f9e p[d] ^u blott+-pap]1 close to a fire1 or ^u a heat$ metallic plate4 ,! sample mu/ also be r$uc$ to a f9e p[d] be=e add+ ! ,oil ( ,vitriol2 o!rwise portions ( ! salt escape decomposition4 ,^! prelim9>ies hav+ be5 prop]ly obs]v$1 weigh out ,pure ,nitre1 p[d]$ & dri$1 #fjj gra9s4 ,?is quantity is equival5t to #a-a_/d ounce ,troy or ,apo!c>ies' weight2--& to #a-a_/d ounce ,avoirdupois weight plus #ed gra9s4 ,place ?is 9 a teacup or any o!r conv5i5t vessel1 & p\r ^u x4 ,wat] #a-a_/b fluid dra*ms mix$ ) ,oil ( ,vitriol #ab ,/ir well ) a glass rod = two or ?ree m9utes1 until all eff]vesc5ce has ceas$1 & an ev51 pa/y mixture1 free f lumps1 is obta9$4 ,dur+ ! :ole process1 abundance ( d5se fumes ( ,nitric ,acid w be giv5 (f1 :i* mu/ be all[$ to escape up ! flue or into ! op5 air4 ,a modification ( ! =mula4--,! above =mula w inv>iably succe$ ) a good sample ( acid & pure ,nitre4 ,:5 tri$ h[ev] ) ,oil ( ,vitriol r weak] ?an ord9>y1 & comm]cial ,nitre1 x may fail1 ! cotton be+ gelat9iz$ & dissolv$4 ,:5 su* is ! case1 ! addition ( wat] mu/ be omitt$ or ! quantity r$uc$ f "o dra*m & a half to half a dra*m4 ,,g5]al ,,directions ,,= ,,imm]s+1 ,,wa%+1 ,,& ,,dry+ ,,! ,,pyroxyl9e4 ,! mixture ( ,sulphuric ,acid & ,nitre requires to be us$ imm$iately aft] its prep>ation1 z x solidifies into a /iff mass on cool+2 b ! mix$ acids may be kept = any l5g? ( "t 9 a /opp]$ bottle4 ,:5 ,cotton is us$1 ! fibres %\ld be well pull$ out1 & small tufts add$ "o by "o to ! acid mixture1 /irr+ ) a glass rod 9 ord] to keep up a con/ant *ange ( p>ticles4 ,! ,pap] is cut into squ>es or /rips1 :i* are introduc$ s+ly4 ,9 ei!r case ! quantity mu/ n be too great1 or "s portions w be imp]fectly act$ ^u2 ab\t #bj gra9s to ea* fluid ounce ( ! mixture w be suffici5t4 ,! "t ( imm]sion requir$ v>ies f t5 m9utes ) ,cotton1 to tw5ty m9utes or ev5 half an h\r ) ! ,pap]4 ,:5 an unusually l>ge proportion ( ,sulphuric ,acid is us$1 z 9 ! case ( a weak sample ( ,nitric ,acid1 ! ,cotton %\ld be remov$ at ! expiration ( six or sev5 m9utes1 z !re is a t5d5cy to p>tial solution ( ! ,pyroxyl9e 9 ! acid mixture "u ^? circum/ances4 ,x is an advantage 9 "s cases to prep>e ! mat]ial at a high temp]ature1 b unless ! proportions ( ! ,acids are /rictly accord+ to ,mr4 ,had['s =mula1 solution ( ! ,cotton may take place if ! !rmomet] indicates m ?an #adj4 ,aft] ! action is complete1 ! ,nitro-,sulphuric ,acid is left weak] ?an be=e1 f addition ( v>i\s atoms ( wat] necess>ily =m$ dur+ ! *ange4 ,h5ce1 if ! same portion be us$ m ?an once1 an addition ( ,sulphuric ,acid w be requir$4 ,directions = ,wa%+4--,9 remov+ ! ,pyroxyl9e f ! ,nitro-,sulphuric ,acid1 press out z mu* ( ! liquid z possible1 & wa% x rapidly 9 a l>ge quantity ( cold wat]1 us+ a glass rod to pres]ve ! f+]s f injury4 ,if x 7 simply ?r[n into a small quantity ( wat] & all[$ to rema91 ! rise 9 temp]ature & weak5+ ( ! acid mixture might d mis*ief4 ,! wa%+ %\ld be cont9u$ = at lea/ a qu>t] ( an h\r1 or long] 9 ! case ( ,pap]1 z x is ess5tial to get rid ( e trace ( acid4 ,:5 ! ,nitre plan has be5 adopt$1 a portion ( ! ,bisulphate ( ,pota% =m$ adh]es to ! fibres1 & if n c>efully wa%$ out1 an opalesc5t appe>ance is se5 9 ! ,collodion1 result+ f ! insolubility ( ?is salt 9 ! e!real mixture4 ,if no acid ta/e c be p]ceiv$1 & a piece ( blue litmus-pap] rema9s 9 contact ) ! fibres = five m9utes )\t *ang+ 9 col\r1 ! product is ?or\ghly wa%$4 ,x is h[ev] a safe plan to place ! ,pyroxyl9e 9 runn+ wat] & all[ x to rema9 = sev]al h\rs4 ,la/ly1 wr+ x out 9 a clo?1 pull out ! fibres1 & dry sl[ly1 by a mod]ate heat4 ,aft] dry+1 x may be kept = any l5g? ( "t 9 a /opp]$ bottle4 ,,recapitulation ,,( ,,! ,,g5]al ,,*>act]s ,,( ,,pyroxyl9e ,,prep>$ ,,9 ,,nitro-,,sulphuric ,,acid ,,( ,,v>i\s ,,degrees ,,( ,,conc5tration4 ,! acid mixture too /rong4--,! appe>ance ( ! cotton is n mu* alt]$ on its fir/ imm]sion 9 ! mixture4 ,x wa%es well1 )\t any dis9tegration4 ,on dry+1 x is f\nd to be /rong 9 texture1 & produces a peculi> crackl+ s5sation betwe5 ! f+]s1 l />*4 ,x explodes on ! application ( flame1 )\t leav+ any a%4 ,x is insoluble 9 ! mixture ( ,e!r & ,alcohol1 b dissolves if treat$ ) ,acetic ,e!r4 ,! acid mixture ( ! prop] /r5g?4--,no agglut9ation ( ! fibres ( ! cotton on imm]sion1 & ! product wa%es well2 soluble 9 ! e!real mixture1 & yields a transp>5t film on evaporation4 ,! acid mixture too weak4--,! fibres ( ! cotton agglut9ate1 & ! ,pyroxyl9e is wa%$ ) difficulty4 ,on dry+1 ! texture is f\nd to be %ort & rott54 ,x does n explode on be+ heat$1 b ei!r burns quietly ) a flame1 leav+ beh9d a black a%--9 :i* case x consi/s simply ( unalt]$ cotton1--or is only slightly combu/ible1 & n explosive4 ,x dissolves m or less p]fectly 9 glacial ,acetic ,acid4 ,:5 treat$ ) ! e!real mixture1 x is act$ on p>tially1 leav+ beh9d lumps ( un*ang$ cotton2 ! solution does n =m an ev5 transp>5t lay] on evaporation1 b becomes opaque & cl\dy z x dries4 ,?is opacity h[ev] may be se5 to a small ext5t ) any sample ( ,pyroxyl9e1 if ! solv5ts conta9 too mu* wat]4 ,9 us+ ,sw$i% ,pap] 9 place ( ,cotton1 ! ,pyroxyl9e =m$ 9 too weak a ,nitro-,sulphuric ,acid is usually insoluble 9 ,e!r & ,alcohol1 & burns sl[ly l un*ang$ pap]4 ,by /udy+ ^! *>act]s1 & at ! same "t be>+ 9 m9d t a dra*m & a half ( wat] 9 ! quantities ( acid giv5 9 ! =mula 7p4 #ahh7 w suffice to cause ! diff]5ce1 ! op]ator w ov]come all difficulties4 ,,purification ,,( ,,! ,,solv5ts ,,requir$ ,,= ,,collodion4 ,! purity ( ! ,e!r employ$ is a matt] ( z mu* importance 9 ! manufacture ( a good ,collodion z t ( any o!r +r$i5t2 ?is po9t mu/ be att5d$ to 9 ord] to secure a good result4 ,!re are f\r k9ds ( ,e!r sold by manufactur+ *emi/s2 fir/1 ord9>y rectifi$ ,sulphuric ,e!r1 conta9+ a c]ta9 p]c5tage ( ,alcohol & ( wat]2 specific gravity ab\t #gej4 ,second1 ! wa%$ ,e!r1 :i* is ! same agitat$ ) an equal bulk ( wat]1 to remove ! ,alcohol3 by ?is proce$+ ! specific gravity ( ! fluid is r$uc$ consid]ably4 ,?ird1 ,e!r bo? wa%$ & re-rectifi$ f a cau/ic alkali1 s z to conta9 nei!r ,alcohol nor wat]2 9 ?is case ! specific gravity %\ld n be high] ?an #gbj4 ,f\r?1 ,me?ylat$ ,e!r1 manufactur$ at a l[] price ?an ! o!rs4 ,rectifi$ ,e!r ( #gej is n to be dep5d$ on1 inasmu* z ! specific gravity is (t5 made up by add+ wat] in/ead ( alcohol4 ,me?ylat$ ,e!r %\ld be us$ only :5 economy is an object1 z x is prone to acidity & less c]ta9 9 its prop]ties4 ,"s ( ! qualities :i* r5d] ,e!r unfit = ,photographic purposes1 are z foll[s3--a peculi> & disagreeable smell1 ei!r ( "s ess5tial oil1 or ( ,acetic ,e!r2 an acid reaction to te/-pap]2 a prop]ty ( turn+ alcoholic solution ( ,iodide ( ,potassium br[n ) unusual rapidity2 an alkal9e reaction to te/-pap]2 a high specific gravity1 f sup]abundance ( ,alcohol & wat]4 ,! ,e!r :i* has be5 bo? wa%$ & r$i/ill$ is always ! mo/ uni=m 9 composition1 & especially s if ! second di/illation be conduct$ f ,quicklime1 ,c>bonate ( ,pota%1 or ,cau/ic ,pota%4 ,^! ,alkal9e sub/ances reta9 ! impurities1 :i* are (t5 ( an acid nature1 & leave ! ,e!r 9 a fit /ate = use4 ,! r$i/illation ( ,e!r is a simple process3 9 deal+ ) ?is fluid h[ev] ! greate/ caution mu/ be ex]cis$1 on acc\nt ( its inflammable nature4 ,ev5 9 p\r+ ,e!r f "o bottle into ano!r1 if a light ( any k9d be ne>1 ! vap\r is apt to take fire2 & sev]e injuries h be5 occasion$ f ?is cause4 ,purification ( ,e!r by r$i/illation f a cau/ic or c>bonat$ alkali4--,take ord9>y rectifi$ ,sulphuric ,e!r1 & agitate x ) an equal bulk ( wat] to wa% out ! ,alcohol2 /& = a few m9utes until ! cont5ts ( ! bottle sep>ate into two di/9ct /rata1 ! l[] ( :i*--id e/1 ! wat]y /ratum--is to be drawn (f & reject$4 ,!n introduce ,cau/ic ,pota%1 f9ely p[d]$1 9 ! proportion ( ab\t "o ounce to a p9t ( ! wa%$ ,e!r2 %ake ! bottle aga9 _m times1 9 ord] t ! wat]--a small portion ( :i* is /ill pres5t 9 solution 9 ! ,e!r--may be ?or\ghly absorb$4 ,aft]w>ds set aside = tw5ty-f\r h\rs 7n long]1 or ! ,pota% may beg9 to decompose ! ,e!r71 :5 x w probably be obs]v$ t ! liquid has become yell[1 & t a floccul5t deposit has =m$ 9 small quantity4 ,transf] to a retort ( mod]ate capacity1 support$ 9 a saucepan ( w>m wat]1 & prop]ly connect$ ) a cond5s]4 ,on apply+ a g5tle heat1 ! ,e!r di/ils ov] quietly1 & cond5ses ) v little loss2 c>e mu/ be tak5 t none ( ! alkal9e liquid conta9$ 9 ! body ( ! retort f9ds its way1 by projection or o!rwise1 into ! neck1 s z to run d[n & contam9ate ! di/ill$ fluid4 ,a m economical plan ( purify+ ,e!r is1 )\t previ\s wa%+ ) wat]1 to agitate ) ,c>bonate ( ,pota% or ) ,quicklime1 & r$i/il at a mod]ate temp]ature4 ,9 ord] to pres]ve ,e!r f decomposition1 x mu/ be kept 9 /opp]$ bottles1 ne>ly full1 & 9 a d>k place4 ,! /opp]s %\ld be ti$ ov] ) bladd] & lut$1 or a consid]able am\nt ( evaporation w take place1 unless ! neck ( ! bottle has be5 gr\nd ) unusual c>e4 ,aft] ! lapse ( "s mon?s1 probably a c]ta9 am\nt ( decomposition1 evid5c$ by ! lib]ation ( ,iod9e on add+ ,iodide ( ,potassium1 w be f\nd to h tak5 place4 ,?is h[ev] is small 9 am\nt1 & n ( a "* to injure ! fluid4 ,rectification ( ,spirits ( ,w9e f ,c>bonate ( ,pota%4--,! object ( ?is op]ation is to remove a portion ( wat] f ! _s1 & s to increase its /r5g?4 ,alcohol ?us purifi$ may be add$ to ,collodion almo/ to any ext5t1 )\t produc+ glut9osity & rott5ness ( film4 ,! salt t]m$ ,c>bonate ( ,pota% is a deliquesc5t salt1--t is1 x has a great attraction = wat]2 consequ5tly :5 ,spirits ( ,w9e are agitat$ ) ,c>bonate ( ,pota%1 a portion ( wat] is remov$1 ! salt dissolv+ 9 x & =m+ a d5se liquid1 :i* refuses to mix ) ! ,alcohol1 & s9ks to ! bottom4 ,at ! expiration ( two or ?ree days1 if ! bottle has be5 %ak5 frequ5tly1 ! action is complete1 & ! l[] /ratum ( fluid may be drawn (f & reject$4 ,pure ,c>bonate ( ,pota% is an exp5sive salt1 & a common] v>iety may be tak54 ,x %\ld be well dri$ on a heat$ metal plate1 & p[d]$1 be=e use4 ,! quantity may be ab\t two ounces to a p9t ( _s2 or m1 if an unusually conc5trat$ ,alcohol is requir$4 ,aft] ! di/illation is complete1 a fluid is obta9$ conta9+ ab\t #ij p] c5t1 ( absolute ,alcohol1 ! rema9+ #aj p] c5t1 be+ wat]4 ,! specific gravity at #fj ,fahr5heit %\ld be f #hae to #hbe2 comm]cial ,_s ( ,w9e be+ #hcf to #hdj4 ,,prep>ation ,,( ,,! ,,iodiz+ ,,comp\nds ,,9 ,a ,,/ate ,,( ,,purity4 ,^! are ! ,iodides ( ,potassium1 ,ammonium1 & ,cadmium4 ,! prop]ties ( ea* are m fully describ$ 9 ,"p ,,iii4 a4 ,! ,iodide ( ,potassium4--,iodide ( ,potassium1 z sold 9 ! %ops1 is (t5 contam9at$ ) v>i\s impurities4 ,! fir/ & mo/ rem>kable is ,c>bonate ( ,pota%4 ,:5 a sample ( ,iodide ( ,potassium conta9s mu* ,c>bonate ( ,pota%1 x =ms small & imp]fect cry/als1 :i* are /rongly alkal9e to te/-pap]1 & become moi/ on exposure to ! air1 f ! deliquesc5t nature ( ! ,alkal9e ,c>bonate4 ,sulphate ( ,pota% is also a common impurity2 x may be detect$ by ,*loride ( ,b>ium4 ,a ?ird impurity ( ,iodide ( ,potassium is ,*loride ( ,potassium2 x is detect$ z foll[s3--,precipitate ! salt by an equal weight ( ,nitrate ( ,silv]1 & treat ! yell[ mass ) solution ( ,ammonia2 if any ,*loride ( ,silv] is pres5t1 x dissolves 9 ! ,ammonia1 &1 aft] filtration1 is precipitat$ 9 :ite curds by ! addition ( an excess ( pure ,nitric ,acid4 ,if ! ,nitric ,acid employ$ is n pure1 b conta9s traces ( free ,*lor9e1 ! ,iodide ( ,silv] mu/ be well wa%$ ) di/ill$ wat] be=e treat+ x ) ,ammonia1 or ! excess ( free ,nitrate ( ,silv] dissolv+ 9 ! ,ammonia w\ld1 on neutraliz+1 produce ,*loride ( ,silv]1 & s cause an error4 ,iodate ( ,pota% is a f\r? impurity (t5 f\nd 9 ,iodide ( ,potassium3 to detect x1 add a drop ( dilute ,sulphuric ,acid1 or a cry/al ( ,citric ,acid1 to ! solution ( ! ,iodide2 :51 if mu* ,iodate be pres5t1 ! liquid w become yell[ f lib]ation ( free ,iod9e4 ,! rationale ( ?is reaction is z foll[s3--,! ,sulphuric ,acid unites ) ! base ( ! salt1 & lib]ates ,hydriodic ,acid 7,,hi71 a col\rless comp\nd2 b if ,iodic ,acid 7,,io#e7 be also pres5t1 x decomposes ! ,hydriodic ,acid fir/ =m$1 oxidiz+ ! ,hydrog5 into ,wat] 7,,ho71 & sett+ free ! ,iod9e4 ,! imm$iate production ( a yell[ col\r on add+ a weak acid to aque\s solution ( ,iodide ( ,potassium1 is !re=e a pro( ( ! pres5ce ( an ,iodate4 ,z ,iodate ( ,pota% r5d]s ,collodion ins5sitive1 ?is po9t %\ld be att5d$ to4 ,iodide ( ,potassium may be r5d]$ v pure by recry/alliz+ f ,_s1 or by dissolv+ 9 /rong ,alcohol ( sp4 gr4 #hbc1 9 :i* ,sulphate1 ,c>bonate1 & ,iodate ( ,pota% are insoluble4 ,! proportion ( ,iodide ( ,potassium conta9$ 9 saturat$ ,alcoholic solutions v>ies ) ! /r5g? ( ! _s 7vide ,"p ,,iii41 article ,iodide ( ,potassium74 ,solution ( ,*loride ( ,b>ium is commonly us$ to detect impurities 9 ,iodide ( ,potassium2 x =ms a :ite precipitate if ,c>bonate1 ,iodate1 or ,sulphate be pres5t4 ,9 ! two =m] cases ! precipitate dissolves on ! addition ( pure dilute ,nitric ,acid1 b 9 ! latt] x is insoluble4 ,! comm]cial ,iodide h[ev] is r>ely s pure z to rema9 q cle> on ! addition ( ,*loride ( ,b>ium4 b4 ,! ,iodide ( ,ammonium4--,?is salt may be prep>$ by add+ ,c>bonate ( ,ammonia to ,iodide ( ,iron1 b m easily by ! foll[+ process3--,a /rong solution ( ,hydrosulphate ( ,ammonia is fir/ made1 by pass+ ,sulphurett$ ,hydrog5 gas into ,liquor ,ammoni4 ,to ?is liquid1 ,iod9e is add$ until ! :ole ( ! ,sulphuret ( ,ammonium has be5 conv]t$ into ,iodide4 ,:5 ?is po9t is rea*$1 ! solution at once col\rs br[n f solution ( free ,iod9e4 ,on ! fir/ addition ( ! ,iod9e1 an escape ( ,sulphurett$ ,hydrog5 gas & a d5se deposit ( ,sulphur take place4 ,aft] ! decomposition ( ! ,hydrosulphate ( ,ammonia is complete1 a portion ( ,hydriodic ,acid--=m$ by ! mutual reaction ( ,sulphurett$ ,hydrog5 & ,iod9e--attacks any ,c>bonate ( ,ammonia :i* may be pres5t1 & causes an eff]vesc5ce4 ,! eff]vesc5ce be+ ov]1 ! liquid is /ill acid to te/-pap]1 f excess ( ,hydriodic ,acid2 x is to be cauti\sly neutraliz$ ) ,ammonia1 & evaporat$ by ! heat ( a wat]-ba? to ! cry/alliz+ po9t4 ,! cry/als %\ld be ?or\ghly dri$ ov] a di% ( ,sulphuric ,acid1 & !n seal$ 9 tubes2 by ?is means x w be pres]v$ col\rless4 ,iodide ( ,ammonium is v soluble 9 ,alcohol1 b x is n advisable to keep x 9 solution1 f ! rapidity ) :i* x decomposes & becomes br[n4 ,! mo/ common impurity ( comm]cial ,iodide ( ,ammonium is ,sulphate ( ,ammonia2 x is detect$ by its sp>+ solubility 9 ,alcohol4 ,c>bonate ( ,ammonia is also frequ5tly pres5t to a l>ge ext5t1 9 :i* case an alkal9e ,collodion & ev5tually an alkal9e ,nitrate ,ba? w be produc$4 e4 ,iodide ( ,cadmium4--,?is salt is =m$ by heat+ fil+s ( metallic ,cadmium ) ,iod9e1 or by mix+ ! two toge!r ) addition ( wat]4 ,iodide ( ,cadmium is v soluble bo? 9 ,alcohol & ,wat]2 ! solution yield+ on evaporation l>ge six-sid$ tables ( a pe>ly lu/re1 :i* are p]man5t 9 ! air4 ,! comm]cial ,iodide is sometimes contam9at$ ) ,iodide ( ,z9c2 ! cry/als be+ imp]fectly =m$ & sl[ly lib]at+ ,iod9e :5 dissolv$ 9 ,e!r & ,alcohol4 ,pure ,iodide ( ,cadmium rema9s ne>ly or q col\rless 9 ,collodion1 if ! fluid be kept 9 a cool & d>k place4 ,,*apt] ,,ii4 ,,=mul ,,= ,,solutions ,,requir$ ,,9 ,,! ,,collodion ,,process4 ,section ,i4--,solutions = direct ,positives4 ,section ,,ii4--,solutions = ,negative ,photographs4 ,,section ,i4 ,=mul = ,solutions = direct ,positives4 ,! solutions are tak5 9 ! foll[+ ord]2--,! ,collodion4--,! ,nitrate ,ba?4--,develop+ fluids4--,fix+ liquids4--,:it5+ solution4 ,,! ,,collodion4 ,=mula ,no4 #a4 ,purifi$ ,e!r1 sp4 gr4 #gbj #e fluid dra*ms4 ,purifi$ ,alcohol1 sp4 gr4 #hbe #c ,pyroxyl9e #c to #e gra9s4 ,pure ,iodide ( ,cadmium or ,ammonium #d gra9s4 ,=mula ,no4 #b4 ,rectifi$ ,e!r1 sp4 gr4 #gej #f fluid dra*ms4 ,spirits ( ,w9e1 sp4 gr4 #hcf #b ,pyroxyl9e #b to #d gra9s4 ,iodide ( ,potassium or ,ammonium #c to #d ,if ! op]ator wi%es to prep>e a /ock ( ! pla9 ,collodion1 & to iodize z requir$1 ! la/ =mula w /& ?us3-- ,rectifi$ ,e!r1 #gej #c fluid ounces4 ,alcohol ( #hcf #b fluid dra*ms4 ,pyroxyl9e #h to #ad gra9s4 ,dissolve ! ,pyroxyl9e1 & let ! fluid /& = =ty-eight h\rs to subside1 !n draw (f cle>1 ) a siphon4 ,to ea* fluid ounce ( ?is pla9 ,collodion add ab\t two fluid dra*ms ( ! foll[+ iodiz+ mixture3-- ,alcohol1 sp4 gr4 #hcf #a fluid ounce4 ,iodide ( ,potassium #af gra9s4 ,( ! two =mul above giv51 ! fir/ is consid]$ ! be/1 b ! second may be sub/itut$ = x :5 highly rectifi$ spirits _c be obta9$4 ,iodide ( ,ammonium *emically pure is p]haps sup]ior to any o!r ,iodide = prep>+ a portrait ,collodion1 b ,iodide ( ,cadmium1 ) addition ( free ,iod9e1 possesses bett] keep+ prop]ties1 & gives v good results4 ,a mixture ( ! two ,iodides may also be us$ advantage\sly1 or ,iodide ( ,potassium may be comb9$ ) ,iodide ( ,cadmium3 ?is prep>ation has be5 mu* recomm5d$1 b ! ,collodion w be liable to produce a spott$ film unless ! salts are q pure4 ,! exact quantity ( ,pyroxyl9e w v>y ) ! temp]ature at :i* ! prep>ation 0 made4 ,! ,collodion %\ld fl[ smoo?ly on ! glass & rema9 free f crapy l9es on sett+4 ,:5 ,iodide ( ,cadmium is us$1 ! t5d5cy to glut9osity w be a little great] ?an usual1 :i* mu/ be obviat$ by ! directions giv5 at page #hc4 ,! film1 aft] dipp+ 9 ! ,ba?1 %\ld appe> opalesc5t & n too yell[ & creamy4 ,pale-blue films yield v good ,positives1 b ) m liability to failure ?an ?ick] films 7p4 #aji74 ,if ! ,positives are n p]fectly cle> & transp>5t 9 ! %ad[s1 dissolve #e gra9s ( ,iod9e 9 an ounce ( ,spirits ( ,w9e 7n me?ylat$71 & add a few drops until ! ,collodion assumes a gold5-yell[ col\r4 ,9 hot wea!r advantage w be ga9$ by some:at increas+ ! quantity ( ,alcohol 9 ,collodion2 ! evaporation ( ! solv5ts be+ ret>d$1 & ! film r5d]$ less liable to become dry be=e developm5t4 ,anhydr\s ,alcohol ( ,sp4 ,gr4 #gif1 may be mix$ ) pure ,e!r ( #gae1 ev5 to ! ext5t ( equal p>ts2 b ?is is ! extreme limit1 & ) ! /ronge/ _s ord9>ily obta9able1 ! ,collodion w (t5 become some:at glut9\s if ! proportions 7by measure7 ( #e p>ts ( ,e!r to #c ( ,alcohol be exce$$4 ,collodion prep>$ by ,=mula ,no4 #a1 & iodiz$ ) ,iodide ( ,cadmium1 may be kept = weeks or mon?s )\t mu* loss ( s5sitiv5ess2 b :5 ,alkal9e ,iodides are employ$ z 9 ! second ,=mula1 ,iod9e is lib]at$1 & ! fluid becomes at la/ br[n & ins5sitive4 ,,! ,,nitrate ,,ba?4 ,nitrate ( ,silv] #cj gra9s4 ,nitric ,acid #a_/bj m9im1 or ,acetic ,acid 7glacial7 #a_/f m9im4 ,alcohol #ae m9ims4 ,di/ill$ wat] #a fluid ounce4 ,nitrate ( ,silv] :i* has be5 melt$1 9 ord] to expel ,oxides ( ,nitrog51 is always ! mo/ c]ta9 9 its action3 b ! heat mu/ n be rais$ too high or ! salt w be contam9at$ ) ,nitrite ( ,silv]4 ,9 ! ,vocabul>y 7see ,"p ,,iii47 directions are giv5 = ! prep>ation & purification ( ,nitrate ( ,silv]2 also = ! te/+ ( di/ill$ wat]1 & ! be/ sub/itutes :5 x _c be obta9$4 ,! ,ba? mu/ be saturat$ ) ,iodide ( ,silv]1 & ,nitric ,acid neutraliz$ if x be pres5t4 ,nitrate ( ,silv] h[ev] :i* has und]gone fusion is free f ,nitric ,acid4 ,weigh out ! total quantity ( cry/als ( ,nitrate requir$ = ! ,ba?1 & dissolve 9 ab\t two p>ts ( wat]4 ,!n take a qu>t] ( a gra9 ( ,iodide ( ,potassium to ea* #ajj gra9s ( ,nitrate1 dissolve 9 half a dra*m ( wat]1 & add to ! /rong solution2 a yell[ deposit ( ,iodide ( ,silv] fir/ =ms1 b on /irr+ is completely re-dissolv$4 ,:5 ! liquid is cle>1 te/ = free ,nitric ,acid by dropp+ 9 a piece ( blue litmus-pap]4 ,if at ! expiration ( two m9utes ! pap] appe>s r$d5$1 ,nitric ,acid is pres5t1 to neutralize :i*1 add solution ( ,pota% or ,c>bonate ( ,soda 7n ,ammonia7 until a di/9ct turbidity1 rema9+ aft] agitation1 is produc$ 7an excess does no h>m74 ,!n dilute d[n ! conc5trat$ solution ) ! rema9+ portion ( ! wat]1 /irr+ all ! "t1 & filt] out ! milky deposit4 ,if ! liquid does n at fir/ run cle>1 x w probably d s on pass+ x aga9 ?r\gh ! same filt]4 ,la/ly1 add ! ,acetic ,acid 7previ\sly te/$ = impurities1 see ,"p ,,iii47 & ! ,alcohol to ! filt]$ liquid4 ,z ! bulk ( ! ,ba? becomes less5$ by use1 fill x up ) a solution conta9+ #dj gra9s ( ,nitrate to ! ounce1 :i* w be f\nd suffici5t to ma9ta9 ! /r5g? ne>ly at ! orig9al po9t4 ,! common practice ( occasionally dropp+ ,ammonia or ,pota% into ! solution1 to remove ,nitric ,acid lib]at$ by free ,iod9e 9 ! ,collodion1 is n recomm5d$ 7see p4 #hi74 ,:5 ! ,ba? becomes old1 & yields ,positives :i* are highly int5se or /a9$1 & slightly foggy1 ) a defici5cy ( half-tone1 x w be advisable to precipitate x ) a ,*loride & prep>e a new "o4 ,,! ,,develop+ ,,fluids4 ,ei!r ( ! ?ree foll[+ =mul may be us$1 accord+ to ! ta/e ( ! op]ator3-- ,,=mula ,no4 #a4 ,sulphate ( ,iron1 recry/alliz$ #ab to #bj gra9s4 ,acetic ,acid 7glacial7 #bj m9ims4 ,alcohol #aj m9ims4 ,wat] #a fluid ounce4 ,,=mula ,no4 #b4 ,pyrogallic ,acid #b gra9s4 ,nitric ,acid #a drop4 ,wat] #a fluid ounce4 ,,=mula ,no4 #c4 ,solution ( ,protonitrate ( ,iron #a fluid ounce4 ,alcohol #bj m9ims4 ,9 all ^! =mul1 if di/ill$ wat] is n at h&1 read ! directions 9 ! ,vocabul>y1 ,"p ,,iii41 ,article ,wat]1 = ! be/ sub/itute4 ,rem>ks ^u ^! ,=mul4--,=mula ,no4 #a is ! mo/ simple1 s9ce ! solution c be us$ z a ,ba?1 ! same portion be+ employ$ _m times successively4 ,if x acts too rapidly1 less5 ! proportion ( ,sulphate ( ,iron4 ,an addition ( ,nitric ,acid1 half a m9im to ! ounce1 makes ! image :it] & m metallic2 b if too mu* is us$1 ! developm5t proce$s irregul>ly1 & spangles ( ,silv] are =m$4 ,! ,alcohol & ,acetic ,acid r5d] ! developm5t uni=m by caus+ ! solution ( ,protosulphate to comb9e m readily ) ! film4 ,! latt] also has an effect 9 :it5+ ! image & increas+ its brightness4 ,solution ( ,sulphate ( ,iron becomes r$ on keep+1 f a gradual =mation ( p]salt4 ,:5 x is too weak1 add m ( ! ,protosulphate4 ,! muddy deposit :i* settles to ! bottom ( ! ,ba? is metallic ,silv]1 r$uc$ f ! soluble ,nitrate ^u ! plates4 ,"s op]ators add pure ,nitrate ( ,pota% to ?is develop+ solution1 to =m a small portion ( ,protonitrate ( ,iron4 ,x is said to improve ! col\r slightly4 ,! proportions are #aj gra9s ( ,nitrate ( ,pota% to ab\t #ad or #ae gra9s ( ,protosulphate ( ,iron4 ,=mula ,no4 #b4--;,9 ?is =mula1 if ! col\r ( ! image is n suffici5tly :ite1 try ! effect ( increas+ ! am\nt ( ,nitric ,acid slightly4 ,on ! o!r h&1 if ! developm5t is imp]fect 9 p>ts1 & pat*es ( a gre5 col\r are se51 use ?ree gra9s ( ,pyrogallic ,acid to ! ounce1 ) less ,nitric ,acid4 ,a few drops ( ,nitrate ( ,silv] solution add$ to ! ,pyrogallic1 imm$iately be=e use1 w augm5t ! en]gy ( developm5t :5 blue & gre5 spots occur4 ,=mula ,no4 #c1 or ,protonitrate ( ,iron1 does n require any addition ( ,acid2 b x w be advisable1 9 "s cases1 to add to x a few drops ( ,nitrate ( ,silv] imm$iately be=e develop+4 ,x gives a bright metallic image1 resembl+ t obta9$ by add+ ,nitric ,acid to ,protosulphate ( ,iron4 ,! foll[+ process is commonly foll[$ = prep>+ ,protonitrate ( ,iron3-- ,take ( ,nitrate ( ,b>yta #cjj gra9s2--p[d] & dissolve by ! aid ( heat 9 ?ree ounces ( wat]4 ,!n ?r[ 9 by degrees1 ) con/ant /irr+1 cry/alliz$ ,sulphate ( ,iron1 p[d]$1 #cbj gra9s4 ,cont9ue to /ir = ab\t five or t5 m9utes4 ,all[ to cool1 & filt] f ! :ite deposit1 :i* is ! insoluble ,sulphate ( ,b>yta4 ,9 place ( ,nitrate ( ,b>yta1 ! ,nitrate ( ,lead may be us$ 7,sulphate ( ,lead be+ an insoluble salt71 b ! quantity requir$ w be diff]5t4 ,! atomic weights ( ,nitrate ( ,b>yta & ,nitrate ( ,lead are z #aca to #aff2 consequ5tly #cjj gra9s ( ! =m] are equival5t to #chj gra9s ( ! latt]4 ,,! ,,fix+ ,,solution4 ,cyanide ( ,potassium #b to #ab gra9s4 ,common ,wat] #a fluid ounce4 ,cyanide ( ,potassium is usually pref]r$ to ,hyposulphite ( ,soda = fix+ direct ,positives2 x is less liable to injure ! purity ( ! :ite col\r4 ,! p]c5tage ( ,c>bonate ( ,pota% 9 comm]cial ,cyanide ( ,potassium is s v>iable t no exact directions c be giv5 = ! =mula4 ,x is be/ h[ev] to use x r dilute--( su* a /r5g? t ! plate is cle>$ gradually 9 f half a m9ute to a m9ute4 ,! solution ( ,cyanide ( ,potassium decomposes sl[ly on keep+1 b x w usually reta9 its solv5t p[] = sev]al weeks4 ,9 ord] to escape inconv5i5ce f ! pung5t od\r evolv$ by ?is salt1 _m employ a v]tical ,ba? to hold ! solution2 b 9 t case ! plates mu/ be c>efully wa%$ be=e fix+1 z ! ,iron salts ha/5 ! decomposition ( ! ,cyanide4 ,,! ,,:it5+ ,,solution4 ,bi*loride ( ,m]cury #cj gra9s4 ,di/ill$ ,wat] #a fluid ounce4 ,by a g5tle application ( heat ! corrosive sublimate dissolves & =ms a solution z ne>ly z possible saturat$ at common temp]atures4 ,! addition ( a portion ( ,muriatic ,acid enables ! wat] to take up a l>g] quantity ( ,bi*loride2 b ?is conc5trat$ solution1 at ! same "t t x :it5s m quickly ?an ! o!r1 is apt to act unequally ^u diff]5t p>ts ( ! image4 ,be=e apply+ ! ,bi*loride1 ! image is to be fix$ & ! plate well wa%$4 ,ei!r ! ,protosulphate ( ,iron or ! ,pyrogallic ,acid ) ,acetic 7p4 #bbc7 may be us$ = ! developm5t2 b ! :it5+ process is m rapid & uni=m 9 ! latt] case4 ,,section ,,ii4 ,=mul1 etc41 = ,negative ,solutions4#cd #cd ,! same ,collodion & ,nitrate ,ba? may be us$ bo? = ,positives & ,negatives if requir$2 b !re are a few m9or po9ts ( diff]5ce :i* are includ$ 9 ! foll[+ rem>ks4 ,,! ,,collodion4 ,,=mula ,no4 #a4 ,purifi$ ,e!r1 sp4 gr4 #gbj #e fluid dra*ms4 ,purifi$ ,alcohol1 sp4 gr4 #hbe #c fluid dra*ms4 ,soluble ,pyroxyl9e #d to #h gra9s4 ,pure ,iodide ( ,cadmium or ,ammonium #d to #e gra9s4 ,,=mula ,no4 #b4 ,rectifi$ ,e!r1 sp4 gr4 #gej #f fluid dra*ms4 ,alcohol1 sp4 gr4 #hcf #b fluid dra*ms4 ,soluble ,pyroxyl9e #d to #h gra9s4 ,iodide ( ,potassium or ,ammonium #d gra9s4 ,:5 ! ,collodion & ,iodiz+ mixture are kept sep>ate1 ! second =mula w /& ?us3-- ,rectifi$ ,e!r #gej #c fluid ounces4 ,alcohol ( #hcf #b fluid dra*ms4 ,pyroxyl9e #ae to #cj gra9s4 ,to ea* fluid ounce ( ?is pla9 ,collodion add #b fluid dra*ms ( ! foll[+ ,iodiz+ solution3-- ,alcohol1 sp4 gr4 #hcf #a fluid ounce4 ,iodide ( ,potassium #bj gra9s4 ,:5 ! temp]ature ( ! ,nitro-,sulphuric ,acid us$ 9 mak+ ! ,pyroxyl9e is high 7#adj to #aee71 x (t5 happ5s t ! ,collodion is too fluid ) #d gra9s ( soluble pap] to ! ounce1 & =ms a blue transp>5t film ( ,iodide on dipp+ ! plate 9 ! ,ba?4 ,9 t case1 increase ! quantity ( ,pyroxyl9e f #d gra9s to #f1 or ev5 to #h gra9s to ea* ounce4 ,if ! ,collodion is glut9\s1 & produces a wavy surface1 ) less ?an #d gra9s ( ,pyroxyl9e to ! ounce1 x is probable t ! ,alcohol is too weak1 or t ! soluble ,cotton is badly made4 ,if flakes ( ,iodide ( ,silv] are se5 loose ^u ! surface ( ! film1 & fall+ away into ! ,ba?1 ! ,collodion is ov]-iodiz$1 & x w be impossible to obta9 a good picture4 ,aft] ! ,collodion has be5 employ$ to coat a numb] ( plates1 ! relative proportions ( ,alcohol & ,e!r conta9$ 9 x become *ang$1 f ! sup]ior volatility ( ! latt] fluid3 :5 x ceases to fl[ readily1 & gives a m d5se film ?an usual1 ?9 x d[n by ! addition ( a little rectifi$ ,e!r4 ,9 dissolv+ ! ,pyroxyl9e1 any fibr\s or floccul5t matt] :i* resi/s ! action ( ! ,e!r1 mu/ be all[$ to subside1 ! cle> portion be+ decant$ = use4 ,! ,iodide ( ,potassium is to be f9ely p[d]$1 & dige/$ ) ! _s until dissolv$2 x is bett] n to apply any heat4 ,bo? ,iodide ( ,ammonium & ,iodide ( ,cadmium dissolve almo/ imm$iately1 if ! salts are pure4 ,! ,collodion mu/ be kept 9 a cool & d>k place4 ,:5 prep>$ ) ,iodide ( ,ammonium or ,potassium x becomes at l5g? high col\r$ & ins5sitive4 ,! free ,iod9e may !n be remov$ by a /rip ( pure z9c or silv]-foil4 ,:5 s5sitiv5ess is n an object1 _m pref] work+ ) an old1 col\r$ ,collodion1 f9d+ t x gives m int5sity4 ,x has be5 %[n at page #ig t a peculi> *ange takes place 9 ,collodion aft] iodiz+1 by :i* ! int5sity ( ! image is increas$4 ,directions = us+ ,glycyrrhiz9e 9 ,collodion4--,! action ( ?is mat]ial has be5 describ$ at page #aad4 ,! ,collodion %\ld be iodiz$ ) ! ,iodide ( ,cadmium only1 or ) a mixture ( ! ,iodides & ,bromides ( ! alkalies4 ,! condition :i* calls = ! employm5t ( ,glycyrrhiz9e is t (t5 f\nd 9 a newly made & r glut9\s ,collodion1 viz4 s5sitiv5ess ( film1 ) good half-tones1 b insuffici5t int5sity 9 ! high lights4 ,dissolve ! ,glycyrrhiz9e 9 ,alcohol 7n ,me?ylat$7 9 ! proportion ( #e gra9s to ! ounce3 ?is solution may p]haps keep un*ang$ = ?ree or f\r mon?s4 ,to ea* ounce ( ! ,collodion add f "o to f\r drops1 & expose 9 ! ,cam]a a few seconds long] ?an be=e4 ,! effect ( ! ,glycyrrhiz9e ^u ! ,collodion may n be fully produc$ imm$iately2 if s1 ! fluid mu/ be set aside = tw5ty-f\r h\rs4 ,use ( ,nitro-glucose 9 ,collodion4--,nitro-glucose is a sub/ance analog\s to ,pyroxyl9e1 b m un/able4 ,:5 add$ to ,collodion iodiz$ ) ! alkal9e ,iodides1 x sl[ly decomposes1 lib]ates ,iod9e1 less5s ! s5sitiv5ess to a c]ta9 ext5t1 & conf]s int5sity4 ,l ,glycyrrhiz9e1 x may be us$ to rem$y feebl5ess ( ! image1 & to give opacity to ! blacks4 ,prep>e ! ,nitro-glucose by ! directions giv5 9 ! ,vocabul>y1 ,"p ,,iii4 ,dissolve tw5ty gra9s 9 an ounce ( pure _s1 & agitate ) p[d]$ *alk to remove free acid4 ,add f five to eight drops to ea* ounce ( ,collodion4 ,9 a few days1 m or less1 accord+ to temp]ature1 ! ,collodion w deep5 9 col\r1 & w be f\nd on trial to produce a m vigor\s picture4 ,collodion = hot ,climates4--,9 ?is case ! ,iodide ( ,ammonium %\ld be avoid$1 z un/able & prone to *ange col\r4 ,iodide ( ,cadmium may be sub/itut$1 :i* has be5 %[n to rema9 q col\rless :5 dissolv$ 9 ,alcohol & ,e!r4 ,collodion iodiz$ ) ! ,iodide ( ,potassium w usually keep = ab\t six weeks or two mon?s2 b no c]ta9 rule c be giv51 mu* dep5d+ ^u ! condition ( ! ,e!r & ! heat ( ! wea!r4 ,pla9 ,collodion may reta9 its prop]ties unimpair$ = five or six mon?s1 sometimes mu* long]2 b !re is a t5d5cy to a =mation ( ! acid pr9ciple 7p4 #he72 & h5ce1 on ! addition ( an alkal9e ,iodide to old ,collodion1 ! coloration is commonly v rapid4 ,! /ructure ( ! transp>5t film may also be injur$ by keep+ pla9 ,collodion = too long a "t4 ,photograph]s :o wi% to op]ate ) ,collodion 9 hot climates w f9d x advantage\s to c>ry ) !m ! prep>$ ,pyroxyl9e & ! spiritu\s solv5ts1 obs]v+ t ! bottles are c>efully lut$1 & t a bubble ( air is left 9 ! neck ( ea*1 to all[ = ! necess>y expansion1 :i* might o!rwise bur/ ! glass or =ce out ! /opp]4 ,,! ,,nitrate ,,ba?4 ,?is solution may be prep>$ by ! same =mula z t giv5 = direct ,positives at page #bjc1 acidify+ ! solution ) ,acetic ,acid 9 pref]5ce to ,nitric ,acid4 ,,! ,,develop+ ,,solution4 ,pyrogallic ,acid #a gra94 ,acetic ,acid 7glacial7 #aj to #bj m9ims1 or ,beaufoy's ,acetic ,acid =t4 #a fluid dra*m4 ,alcohol #aj m9ims4 ,di/ill$ ,wat] #a fluid ounce4 ,9 place ( ,di/ill$ ,wat]1 pure ,ra9-,wat] may be us$ 7see ,"p ,,iii41 ,art4 ,wat]74 ,! quantity ( ,acetic ,acid requir$ w v>y ) ! /r5g? ( ! ,acid & ! temp]ature ( ! atmosph]e4 ,an excess enables ! manipulator to cov] ! plate m easily be=e ! action beg9s1 b :5 ! picture is tak5 9 a dull light1 is apt to give a blui%1 inky hue to ! image4 ,9 cold wea!r1 use less ( ! ,acetic & twice ! quantity ( ,pyrogallic ,acid4 ,) ,collodion prep>$ f ,spirits ne>ly anhydr\s1 & iodiz$ ) ,iodide ( ,cadmium1 ! full quantity ( ,acetic ,acid w be requir$1 z !re is sometimes a little difficulty 9 mak+ ! develop] fl[ up to ! edge ( ! film4 ,if ! image _c be r5d]$ suffici5tly black1 two or ?ree m9ims ( ! ,nitrate ,ba? solution may be add$ to ea* dra*m t[>ds ! end ( ! developm5t4 ,if ! solution be kept = "s "t aft] its fir/ prep>ation1 x becomes br[n & discol\r$4 ,9 ?is /ate x w /ill develope ! image1 b is less likely to give a cle> & vigor\s picture4 ,a solution ( ,pyrogallic ,acid 9 ,acetic ,acid w keep = _m weeks1 & may be dilut$ d[n :5 requir$ = use4 ,! foll[+ is a good =mula3-- ,pyrogallic acid #ab gra9s4 ,beaufoy's ,acetic acid #a fluid ounce4 ,to "o dra*m add sev5 dra*ms ( wat]4 ,,! ,,fix+ ,,liquid4 ,cyanide ( ,potassium #b to #ab to #bj gra9s4 ,wat] #a fluid ounce4 or1 ,hyposulphite ( ,soda #a_/b ounce4 ,wat] #a fluid ounce4 ,= rem>ks on ! ,cyanide ( ,potassium ,fix+ ,ba?1 see ! la/ ,section1 page #bjg4 ,,*apt] ,,iii4 ,,manipulations ,,( ,,! ,,collodion ,,process4 ,^! may be class$ "u five heads3--,clean+ ! ,plates4--,coat+ ) ,iodide ( ,silv]4--,exposure 9 ! ,cam]a4--,develop+ ! image4--,fix+ ! image4--,9 addition to ?is1 ! pres5t ,*apt] w include 9 sep>ate ,sections directions = ! *oice & managem5t ( l5ses1 = copy+ engrav+s1 manuscripts1 etc41 & = tak+ /]eoscopic & microscopic photographs4 ,,clean+ ,,! ,,glass ,,plates4 ,c>e %\ld be tak5 9 select+ glass = use 9 ,photography4 ,! ord9>y w9d[-glass is inf]ior1 hav+ scrat*es ^u ! surface1 ea* ( :i* may cause an irregul> action ( ! develop+ fluid2 & ! squ>es are seldom flat1 s t !y are apt to be brok5 9 compression dur+ ! pr9t+ process4 ,! pat5t plate answ]s bett] ?an any o!r description ( glass2 b if x _c be procur$1 ! flatt$ cr[n glass may be sub/itut$4 ,be=e wa%+ ! glasses1 ea* squ>e %\ld be r\gh5$ on ! edges by means ( a file or a %eet ( em]y-pap]2 or m simply1 by draw+ ! edges ( two plates across ea* o!r4 ,if ?is precaution be omitt$1 ! f+]s are liable to injury1 & ! ,collodion film may contract & sep>ate f ! sides4 ,9 clean+ glasses1 x is n suffici5t1 z a rule1 to wa% !m simply ) wat]2 o!r liquids are requir$ to remove grease1 if pres5t4 ,a cream ( ,tripoli p[d] & ,spirits ( ,w9e1 ) a little ,ammonia add$1 is commonly employ$4 ,a tuft ( cotton is dipp$ 9 ?is mixture1 & ! glasses are well rubb$ ) x = a few m9utes4 ,!y are !n r9s$ 9 pla9 wat] & wip$ dry ) a clo?4 ,! clo?s us$ = clean+ glasses %\ld be kept expressly = t purpose2 !y are be/ made ( a mat]ial sold z f9e diap]1 & v free f flocculi & loosely-adh]+ fibres4 ,!y are n to be wa%$ 9 soap & wat]1 b always 9 pure wat] or 9 wat] conta9+ a little ,c>bonate ( ,soda4 ,aft] wip+ ! glass c>efully1 complete ! process by poli%+ ) an old silk h&k]*ief1 avoid+ contact ) ! sk9 ( ! h&4 ,"s object to silk1 z t5d+ to r5d] ! glass electrical1 & s to attract p>ticles ( du/1 b 9 practice no inconv5i5ce w be exp]i5c$ f ?is s\rce4 ,be=e decid+ t ! glass is clean1 hold x 9 an angul> position & brea! ^u x4 ,! importance ( att5d+ to ?is simple rule w be at once se5 by ref]r+ to ! rem>ks made at page #ci4 ,9 ! ,honey pres]vative & ,collodio-,album5 processes x is especially ne$ful t ! glasses %\ld be ?or\ghly clean$1 on acc\nt ( ! t5d5cy :i* ! film has to become loos5$ or to bli/] dur+ ! developm5t & wa%+s4 ,cau/ic ,pota%1 sold by ! druggi/s "u ! "n ( ,liquor ,potass1 is v efficaci\s1 or 9 place ( x1 a w>m solution ( wa%+ ,soda 7,c>bonate ( ,soda74 ,liquor ,potass1 be+ a cau/ic & alkal9e liquid1 s(t5s ! sk9 & dissolves x2 x mu/ !re=e be dilut$ ) ab\t f\r p>ts ( wat] & appli$ to ! glass by means ( a cyl9drical roll ( flannel4 ,aft] wett+ bo? sides ?or\ghly1 all[ ! glass to /& = a "t until sev]al h be5 treat$ 9 ! same way2 !n wa% ) wat] & rub dry 9 a clo?4 ,! use ( an alkal9e solution is usually suffici5t to clean ! glass1 b "s plates are dott$ on ! surface ) small :ite specks1 n removable by ,pota%4 ,^! specks may consi/ ( h>d p>ticles ( ,c>bonate ( ,lime1 & :5 su* is ! case !y dissolve readily 9 a dilute acid1--,oil ( ,vitriol1 ) ab\t f\r p>ts ( wat] add$1 or dilute ,nitric ,acid4 ,! objection to ! use ( ,nitric ,acid is1 t if all[$ to come 9 contact ) ! dress1 x produces /a9s :i* _c be remov$ unless imm$iately treat$ ) an alkali4 ,a drop ( ,ammonia %\ld be appli$ to ! spot be=e x becomes yell[ & fad$4 ,:5 ,positives are to be tak51 x is advisable to use additional c>e 9 prep>+ ! glass1 & especially s ) pale transp>5t films & neutral1 ,nitrate ,ba?4 ,aft] a glass has be5 once coat$ ) ,collodion1 x is n necess>y 9 clean+ x a second "t to use any?+ b pure wat]2 b if ! film has be5 all[$ to h>d5 & become dry1 possibly dilute ,oil ( ,vitriol or ,cyanide ( ,potassium may be requir$ to remove /a9s4 ,:5 glasses h be5 repeat$ly us$ 9 photography !y (t5 become at l5g? s dull & /a9$1 t x is bett] to reject !m4 ,,coat+ ,,! ,,plate ,,) ,,! ,,collodio-,,iodide ,,( ,,silv]4 ,?is "p ( ! process1 ) t :i* foll[s1 mu/ be conduct$ 9 a room f :i* *emical rays ( light are exclud$4 ,x is inf]r$ !re=e t ! op]ator has provid$ himself ) an ap>tm5t ( t k9d4 ,! mo/ simple plan ( prep>+ ! room is to nail a treble ?ickness ( yell[ calico completely ov] ! w9d[1 or a "p ( x1 ! rema9d] be+ d>k5$4 ,to ?is a s+le ?ickness ( a wat]pro( mat]ial made by coat+ l95 ) gutta-p]*a may be add$ z a fur!r security aga9/ ! entrance ( :ite light1 ! smalle/ p5cil ( :i* admitt$ into ! room w\ld cause fogg+4 ,x is (t5 conv5i5t to illum9ate by means ( a c&le scre5$ by yell[ glass4 ,a d>k orange yell[1 approa*+ to br[n1 is m imp]vi\s to *emical rays ?an a light] can>y-yell[4 ,lamps suitable = ! purpose are sold by ! manufactur]s ( app>atus & *emicals4 ,be=e coat+ ! plate ) ,collodion1 see t ! fluid is p]fectly cle> & transp>5t1 & t all p>ticles h settl$ to ! bottom2 also t ! neck ( ! bottle is free f h>d & dry cru/s1 :i*1 if all[$ to rema91 w\ld p>tially dissolve & produce /ri ^u ! film4 ,9 tak+ small portraits & /]eoscopic subjects1 ^! po9ts are ( especial importance1 & e picture w be spoil$ if !y are n att5d$ to4 ,a useful piece ( app>atus = cle>+ ,collodion is t repres5t$ 9 ! foll[+ woodcut4 ,illu/ration ,! ,collodion1 hav+ be5 iodiz$ "s h\rs previ\sly1 is all[$ to settle d[n & become cle> 9 ?is bottle2 !n by g5tly bl[+ at ! po9t ( ! %ort] tube1 ! small glass siphon is fill$1 & ! fluid drawn (f m closely ?an c\ld be done by simply p\r+ f "o bottle to ano!r4 ,:5 ! ,collodion is prop]ly cle>$ f s$im5t1 ! op]ator takes a glass plate1 previ\sly clean$1 & wipes x g5tly ) a silk h&k]*ief1 9 ord] to remove any p>ticles ( du/ :i* may h subsequ5tly collect$4 ,if x be a plate ( mod]ate size1 x may be held by ! corn]s 9 a horizontal position1 betwe5 ! =ef+] & ?umb ( ! left h&4 ,! ,collodion is to be p\r$ on /eadily until a circul> pool is =m$1 ext5d+ ne>ly to ! edges ( ! glass4 ,illu/ration ,by a slight incl9ation ( ! plate ! fluid is made to fl[ t[>ds ! corn] m>k$ #a1 9 ! above diagram1 until x ne>ly t\*es ! ?umb by :i* ! glass is held3 f corn] #a x is pass$ to corn] #b1 held by ! =ef+]2 f #b to #c1 & la/ly1 ! excess p\r$ back into ! bottle f ! corn] m>k$ ,no4 #d4 ,x is !n to be held v]tically ov] ! bottle = a mom5t1 until x ne>ly ceases to drip1 & !n1 by rais+ ! ?umb a little1 ! direction ( ! plate is *ang$1 s z to cause ! diagonal l9es to coalesce & produce a smoo? surface4 ,! op]ation ( coat+ a plate ) ,collodion mu/ n be done hurri$ly1 & no?+ is requir$ to ensure success b /ead9ess ( h& & a suffici5cy ( ! fluid p\r$ 9 ! fir/ in/ance ^u ! plate4 ,9 coat+ l>g] plates1 ! pneumatic hold]1 :i* fixes itself by suction1 w be f\nd ! mo/ simple & useful4 ,! ,prop] ,"t = imm]s+ ! ,film 9 ! ,ba?4--,aft] expos+ a lay] ( ,collodion to ! air = a %ort "t1 ! great] "p ( ! ,e!r evaporates1 & leaves ! ,pyroxyl9e 9 a /ate 9 :i* x is nei!r wet nor dry1 b receives ! impression ( ! f+] )\t adh]+ to x4 ,photograph]s t]m ?is sett+1 & :5 x takes place x is a sign t ! "t has come = submitt+ x to ! action ( ! ,ba?4 ,if ! film be l[]$ into ! ,nitrate be=e x has set1 ! effect is ! same z t produc$ by add+ ,wat] to ,collodion4 ,! ,pyroxyl9e is precipitat$ 9 "p1 & consequ5tly !re are cracks1 & ! develop] w n always run up to ! edge ( ! film4 ,on ! o!r h&1 if x be all[$ to become too dry1 ! ,iodide ( ,silv] does n =m p]fectly1 & ! film1 on be+ wa%$ & br\ght out to ! light1 exhibits a peculi> iridesc5t appe>ance1 & is pal] 9 "s p>ts ?an 9 o!rs4 ,no rule c be giv5 z to ! exact "t :i* ought to elapse3 x v>ies ) ! temp]ature ( ! atmosph]e1 & ) ! proportions ( ,e!r & ( ,pyroxyl9e2 ?9 ,collodion conta9+ b little ,alcohol requir+ to be imm]s$ m spe$ily4 ,tw5ty seconds 9 ! common way1 or t5 seconds 9 hot wea!r1 w be f\nd an av]age "t4 ,:5 ! plate is ready1 re/ x ^u ! glass dipp]1 ,collodion side upp]mo/1 & l[] x into ! solution by a sl[ & /eady movem5t3 if any pause be made1 a horizontal l9e correspond+ to ! surface ( ! liquid w be =m$4 ,!n place ! cov] ^u ! v]tical tr\gh#ce & d>k5 ! room1 if ?is has n already be5 done4 ,z ! pres5ce ( :ite light does no injury to ! plate previ\s to its imm]sion 9 ! ,ba?1 x is n necess>y to exclude x dur+ ! "t ( coat+ ) ,collodion4 #ce ,tr\ghs made ( gutta-p]*a1 glass1 or porcela9 are commonly us$2 ! latt] are ! be/1 be+ q opaque & n liable to cracks or leak+4 ,:5 ! plate has rema9$ 9 ! solution ab\t tw5ty seconds1 lift x p>tially out two or ?ree times1 9 ord] to wa% away ! ,e!r f ! surface4 ,an imm]sion ( "o m9ute to a m9ute & a half w usually be suffici5t2 or two m9utes 9 cold wea!r1 & ) ,collodion conta9+ b little ,alcohol4 ,cont9ue to move ! plate until ! liquid fl[s (f 9 a uni=m %eet1 :5 ! decomposition may be consid]$ to be suffici5tly p]fect4 ,! pr9cipal imp$im5t 9 ?is "p ( ! process lies 9 ! difficulty ) :i* ,e!r & ,wat] mix toge!r1 :i* causes ! ,collodion surface on its fir/ imm]sion to appe> oily & cov]$ ) /reaks4 ,by g5tle motion ! ,e!r is wa%$ away1 & a smoo? & homog5e\s lay] obta9$4 ,! plate is next remov$ f ! dipp]1 & held v]tically 9 ! h& = a few seconds ^u blott+ pap]1 to dra9 (f z mu* z possible ( ! solution ( ,nitrate ( ,silv]4#cf ,x is !n wip$ on ! back ) filt]+-pap]1 plac$ 9 a clean & dry slide1 & is ready = ! ,cam]a4 #cf ,?is blott+-pap] mu/ be frequ5tly *ang$1 or /a9s w be produc$ at ! l[] edge ( ! plate dur+ ! developm5t4 ,! amateur is /rongly recomm5d$ n to proce$ to take pictures 9 ! ,cam]a until by a little practice he has succe$$ 9 produc+ a p]fect film :i* is uni=m 9 e "p & w be> inspection :5 wa%$ & br\ght out to ! light4 ,x %\ld1 if prop]ly prep>$1 pres5t ! foll[+ appe>ance3--,smoo? & uni=m1 bo? by reflect$ & transmitt$ light2 free f wavy l9es or m>k+s su* z w\ld be caus$ by a glut9\s ,pyroxyl9e1 & f opaque dots due to small p>ticles ( du/ or ,iodide ( ,silv] 9 susp5sion 9 ! ,collodion4 ,! evid5ces ( a too rapid imm]sion 9 ! ,ba? are s\ght = on ! side ( ! plate f :i* ! ,collodion 0 p\r$ (f4 ,?is "p rema9s wet long] ?an ! o!r1 & always suff]s ! mo/2 horizontal cracks or m>ks resembl+ vegetation are se51 ea* ( :i* w\ld cause an irregul> action ( ! develop+ fluid4 ,on ! o!r h&1 ! upp] "p ( ! plate mu/ be exam9$ = ! pale col\r *>act]i/ic ( a film :i* _h become too dry be=e imm]sion1 s9ce ! ,collodion is ?9n] at t po9t ?an at any o!r4 ,,exposure ,,( ,,! ,,plate ,,9 ,,! ,,cam]a4 ,aft] ! plate has be5 r5d]$ s5sitive1 x %\ld be expos$ & develop$ ) all conv5i5t despat*2 ! int5sity ( ! ,negatives be+1 ) "s ,collodion1 mat]ially less5$ by neglect+ ?is po9t 7see p4 #ajj74 ,asc]ta9 t ! jo9ts ( ! ,cam]a are tight 9 e "p--t ! s5sitive plate1 :5 plac$ 9 ! slide1 falls precisely 9 ! same plane z t occupi$ by ! gr\nd glass--& t ! *emical & visual foci ( ! ,l5s accurately correspond4#cg #cg ,see ! ,second ,section ( ?is ,*apt]4 ,suppos+ ! case ( a portrait1 next proce$ to arrange ! sitt] z ne>ly z possible 9 a v]tical position1 t e "p may be equidi/ant f ! l5s4 ,!n1 an imag9>y l9e be+ drawn f ! head to ! knee1 po9t ! ,cam]a slightly d[nw>ds1 s t x may /& at "r angles to ! l9e4 ,if ?is po9t be neglect$ ! figure w be liable to be di/ort$ 9 a mann] pres5tly to be %[n 7p4 #bbh74 ,9 ord] to succe$ well ) portraits1 ! sitt] %\ld be illum9at$ by an ev51 diffus$ light fall+ horizontally4 ,a v]tical light causes a deep %ad[ on ! eyes & makes ! hair appe> grey3 x mu/ !re=e be cut (f by a curta9 ( blue or :ite calico susp5d$ ov] ! head4 ,! direct rays ( ! sun are g5]ally to be avoid$1 z caus+ too great a contra/ ( light & %ade4 ,?is is a po9t on :i* ! op]ator mu/ ex]cise 8 judgm5t4 ,) a feeble ,collodion1 a bett] ,negative picture may (t5 be obta9$ by plac+ ! sitt] q 9 ! op5 air1 b :5 ! ,collodion & ,ba? are 9 ! condition = giv+ great int5sity ( image1 ! gradation ( tone w be inf]ior unless ! light be prev5t$ f fall+ too /rongly ^u ! face & h&s4 ,9 focuss+ ! object1 cov] ! head & ! back "p ( ! ,cam]a ) a black clo?1 & %ift ! ,l5s g5tly until ! greate/ possible am\nt ( di/9ctness is obta9$4 ,!n ins]t ! s5sitive plate1 & hav+ rais$ ! door ( ! slide1 cov] all ) a black clo? dur+ ! exposure1 z a security aga9/ :ite light f9d+ entrance at any "p except+ ?r\gh ! ,l5s4 ,) reg>d to ! prop] "t = ! exposure1 s mu* dep5ds ^u ! brightness ( ! light & ! nature ( ! ,collodion1 t x mu/ be left almo/ entirely to exp]i5ce4 ,! foll[+ g5]al rules h[ev] may be ( use3-- ,9 a tol]ably bright day 9 ! spr+ or summ] mon?s1 & ) a newly-mix$ ,collodion1 all[ f\r seconds = a ,positive ,portrait1 & eight seconds = a ,negative4 ,) a d\ble-comb9ation ,l5s ( l>ge ap]ture & %ort focus1 p]haps ?ree seconds1 & six seconds1 or ev5 less1 may be suffici5t4 ,9 ! dull w9t] mon?s1 9 ! smoky atmosph]e ( l>ge cities1 or :5 us+ an old ,collodion br[n f free ,iod9e1 multiply ^! numb]s ?ree or f\r times1 :i* w be an approximation to ! exposure requir$4 ,x is by ! appe>ance pres5t$ "u ! influ5ce ( ! develop]1 :i* w imm$iately be describ$1 t ! op]ator asc]ta9s ! prop] "t = exposure to light4 ,,! ,,developm5t ,,( ,,! ,,image4 ,! details ( develop+ ! lat5t image diff] s mu* 9 ! case ( ,positive & ,negative pictures1 t x is bett] to describe ! two sep>ately4 ,! developm5t ( direct ,positives4--,) ,sulphate ( ,iron z a develop]1 x is mo/ simple to develope ! image by imm]sion4 ,! solution may conv5i5tly be p\r$ into a v]tical tr\gh1 su* z t us$ = excit+1 & ! plate imm]s$ by means ( a glass dipp] 9 ! usual way4 ,unless ! wea!r be cold1 ! image makes its appe>ance 9 ?ree or f\r seconds1 & ! film is !n imm$iately wa%$ ) cle> wat]4 ,:il/ 9 ! ,ba?1 ! plate is kept 9 g5tle motion1 & ! op]ator mu/ n expect to see ! image v di/9ctly1 except ! high lights2 ! %ad[s1 be+ fa9t1 are p>tially conceal$ by ! unalt]$ ,iodide1 b !y come out dur+ ! fix+4 ,! action ( ! ,sulphate ( ,iron is /opp$ at an e>ly p]iod1 or an excess ( developm5t w be incurr$4 ,! ,ba? may be us$ repeat$ly4 ,9 us+ ,pyrogallic ,acid or ,nitrate ( ,iron to develope glass ,positives1 ! plate may be plac$ ^u a levell+-/&1 or held 9 ! h&1 or by ! pneumatic hold]1 & ! solution p\r$ on quickly at "o corn]2 by bl[+ g5tly or incl9+ ! h&1 z ! case may be1 x is scatt]$ ev5ly ov] ! film be=e ! developm5t comm5ces4 ,if any difficulty is exp]i5c$ 9 cov]+ a plate ev5ly ) a /rong develop] be=e ! action comm5ces1 x may be ov]come by us+ a %all[ cell =m$ by cem5t+ two or ?ree ?icknesses ( w9d[-glass on a piece ( pat5t plate to ! dep? ( a qu>t] ( an in*4 ,! size ( ! cell %\ld be only slightly l>g] ?an ! plate int5d$ to be develop$1 t ! wa/e ( fluid may be z little z possible4 ,! cell is held 9 ! left h&1 & ! plate be+ plac$ 9 x1 a suffici5t quantity ( ! develop] is p\r$ on at "o corn]4 ,by a slight incl9ation1 ! fluid is caus$ to fl[ 9 a uni=m %eet ov] ! surface ( ! film1 backw>ds & =w>ds4 ,! image />ts out quickly1 & ! develop] is !n at once p\r$ (f1 & ! film wa%$ z be=e4 ,x is v important 9 develop+ ,positives to use a suffici5t quantity ( ! solution to cov] ! plate easily2 o!rwise oily /a9s & m>ks are =m$1 f ! develop] n comb9+ prop]ly ) ! surface ( ! film4 ,= a plate five in*es by f\r1 ?ree or f\r dra*ms w be requir$1 & s 9 proportion = l>g] sizes4 ,! appe>ance ( ! ,positive image aft] develop+1 z a guide to ! prop] "t ( exposure4--,:5 ! plate has be5 develop$1 x is wa%$1 fix$1 & laid ^u a d>k gr\nd1 su* z a piece ( black velvet1 = inspection4 ,9 ! case ( a portrait1 if ! features h an unnaturally black & gloomy appe>ance1 ! d>k portions ( ! drap]y1 etc41 be+ invisible1 ! picture has be5 "u-expos$4 ,on ! o!r h&1 9 an ov]-expos$ plate1 ! face is usually pale & :ite1 & ! drap]y mi/y & indi/9ct4 ,mu* h[ev] 9 ?is respect dep5ds ^u ! dress ( ! sitt] 7see p4 #ff71 & ! mann] 9 :i* ! light is ?r[n2 if ! upp] "p ( ! figure is %ad$ too mu*1 ! face may p]haps be ! la/ to be se54 ,! op]ator %\ld accu/om himself to exp5d pa9s 9 ! prelim9>y focuss+ ^u ! gr\nd glass1 & to asc]ta9 at t "t t e "p ( ! object is equally illum9at$4 ,= ?is reason1 pictures tak5 9 a room are seldom successful2 ! light falls entirely ^u "o side1 & h5ce ! %ad[s are d>k & indi/9ct4 ,! developm5t ( ,negative ,pictures4--,?is process diff]s 9 mo/ respects f t ( ,positives4 ,9 ! latt] case1 !re is a t5d5cy to ov]-develope ! image2 b 9 ! =m]1 to /op ! action at too e>ly a p]iod2 h5ce x is common to f9d ,negative ,pictures :i* are insuffici5tly develop$1 & too pale to pr9t well4 ,9 develop+ ,negatives1 _m op]ators place ! plate ^u a levell+-/&1 & di/ribute ! fluid by bl[+ g5tly ^u ! surface2 o!rs pref] hold+ x 9 ! h& & p\r+ ! fluid on & (f f a glass measure4 ,! quantity ( develop] requir$ w be less ?an t us$ = ,positives1 inasmu* z1 if ! ,acetic ,acid be pres5t 9 suffici5t excess1 x is easy to cov] ! plate be=e ! action beg9s4 ,"s ,collodion h[ev]1 especially ! glut9\s k9d1 seems to repel ! develop] & prev5t x f runn+ up to ! edge ( ! plate4 ,:5 ?is is ! case1 or :5 oil9ess & /a9s are produc$1 f ! ,ba? be+ old & conta9+ ,e!r1 ,alcohol mu/ be add$ to ! solution ( ,pyrogallic ,acid4 ,) ord9>y ,negative ,collodion1 an addition ( ,nitrate ( ,silv] to ! develop] w (t5 be requir$2 b ! ,pyrogallic ,acid is to be us$ alone until ! image has rea*$ its maximum ( int5sity1 :i* x w d 9 a m9ute or s1 accord+ to ! temp]ature ( ! develop+ room4 ,! plate may !n be exam9$ leisurely by plac+ x 9 front (1 & at "s di/ance f1 a %eet ( :ite pap]4 ,if x is n suffici5tly black1 add ab\t f\r drops ( ! ,nitrate ,ba? to ea* dra*m ( develop]1 /ir well ) a glass rod1 & cont9ue ! action until ! requisite am\nt ( int5sity is obta9$4 ,:5 !re is any disposition 9 ! plate to fog t[>ds ! end ( ! developm5t1 x may be obviat$ by fix+ ) ,cyanide ( ,potassium 7n ,hyposulphite71 & !n1 aft] a c>eful wa%+1 int5sify+ ) ,pyrogallic ,acid & ,nitrate ( ,silv] 9 ! usual way4 ,! glass :i* conta9s ! mixture ( ,pyrogallic ,acid & ,nitrate ( ,silv] mu/ be wa%$ out aft] ea* plate1 z ! black deposit ha/5s ! discoloration ( ! fre% solution 7p4 #agi74 ,appe>ance ( ! ,negative image dur+ & aft] ! r$uc+ process1 z a guide to ! exposure to light4--,an "u-expos$ plate developes sl[ly4 ,by cont9u+ ! action ( ! ,pyrogallic ,acid1 ! high lights become v black1 b ! %ad[s are invisible1 no?+ b ! yell[ ,iodide be+ se5 on ^? portions ( ! plate4 ,aft] treatm5t ) ! ,cyanide1 ! picture %[s well z a ,positive1 b by transmitt$ light all ! m9or details are invisible2 ! image is black & :ite1 )\t any half-tone4 ,an ov]-expos$ ,negative developes rapidly at fir/1 b soon beg9s to black5 slightly at e "p ( ! plate4 ,aft] ! fix+ is complet$1 no?+ c (t5 be se5 by reflect$ light b a uni=m grey surface ( metallic ,silv]1 )\t any appe>ance 7or1 at mo/1 an indi/9ct "o7 ( an image4 ,by transmitt$ light ! plate may appe> ( a r$ or br[n col\r1 & ! image is fa9t & dull4 ,! cle> p>ts ( ! ,negative be+ obscur$ by ! fogg+1 & ! half-%ad[s hav+ act$ s long z ne>ly to ov]take ! lights1 !re is a want ( prop] contra/2 h5ce ! ov]-expos$ plate is ! exact conv]se ( ! "u-expos$1 :]e ! contra/ betwe5 lights & %ad[s is too well m>k$1 f ! abs5ce ( int]m$iate t9ts4 ,a ,negative :i* has receiv$ ! prop] am\nt ( exposure1 usually possesses ! foll[+ *>act]s aft] ! developm5t is complet$3--,! image is p>tially b n fully se5 by reflect$ light4 ,9 ! case ( a portrait1 any d>k portions ( drap]y %[ well z a ,positive1 b ! features ( ! sitt] are sc>cely to be disc]n$4 ,! plate has a g5]al aspect z ( fogg+ ab\t to comm5ce1 b n actually e/abli%$4 ,by transmitt$ light ! figure is bright1 & appe>s to /& out f ! glass3 ! d>k %ad[s are cle>1 )\t any mi/y deposit ( metallic ,silv]2 ! high lights black almo/ to complete opacity4 ,! col\r ( ! image h[ev] v>ies mu* ) ! /ate ( ! ,ba? & ,collodion & ) ! brightness ( ! light4 ,! rem>ks already made "u ! head ( ,positives1 apply equally well to ,negatives2 t is1 x w be difficult to secure gradation ( tone1 unless ! object be equally illum9at$1 )\t any /rong contra/ ( light & %ade4 ,h5ce ! direct rays ( ! sun are1 z a rule1 to be avoid$1 & curta9s1 etc41 employ$ :5 practicable4 ,,fix+ ,,& ,,v>ni%+ ,,! ,,image4 ,aft] ! developm5t is complet$1 & ! plate has be5 c>efully wa%$ by a /ream ( wat]1 x may be br\ght out to ! light & treat$ ) ! ,hyposulphite or ,cyanide1 until ! unalt]$ ,iodide is entirely cle>$ (f4 ,"s use a ,ba? = ! ,cyanide2 b x is d\btful :e!r mu* sav+ is effect$ by do+ s4 ,! plate is aga9 to be c>efully wa%$ aft] ! fix+2 & especially if ,hyposulphite ( ,soda be us$4 ,?ree or f\r m9utes 9 runn+ wat] w n be too long1 or ! glass may be left 9 a di% ( wat] = an h\r or two4 ,if su* precautions are neglect$1 cry/als =m on dry+1 & ! image is injur$4 ,collodion pictures %\ld be protect$ by a coat ( v>ni%1 bo? ,negatives & ,positives hav+ be5 kn[n to fade :5 expos$ to damp air )\t any cov]+ 7see p4 #aff74 ,to prep>e transp>5t v>ni%4 ,amb] may be dissolv$ 9 ,*lor(orm accord+ to ,dr4 ,diamond's =mula2--ab\t #hj gra9s ( amb]-beads or pipe-/ems %\ld be dige/$ ) "o ounce ( ! ,*lor(orm1 & ! cle> portion sep>at$ by filtration4 ,x may be p\r$ on ! plate 9 ! same mann] z ,collodion1 & dries up spe$ily into a h>d & transp>5t lay]4 ,! ,_s ,v>ni% ord9>ily sold = ,negatives requires ! aid ( heat to prev5t ! gum f *ill+ z x dries2 ! plate is fir/ w>m$ g5tly & ! v>ni% p\r$ on & (f 9 ! usual way2 x is !n1 :il/ /ill dripp+1 held to ! fire until ! ,_s has evaporat$4 ,a few trials w r5d] ! op]ation easy to p]=m4 ,:ite ,lac dissolv$ 9 /rong ,alcohol or 9 ,b5zole has also be5 recomm5d$ = cle> v>ni%4 ,direct ,positives are to be v>ni%$1 fir/ ) a lay] ( transp>5t v>ni%1 & !n ) black japan4 ,suggett's pat5t jet is sometimes employ$1 b x has a disagreeable smell1 & is apt to crack on dry+4 ,! be/ black japan us$ by coa*mak]s is m ela/ic & less liable to crack4 ,asphalt 7#d oz47 dissolv$ 9 m9]al ,naph?a 7#aj oz471 ) ! addition ( #cj gra9s ( ,ca\t*\c dissolv$ 9 half an ounce ( ! same m5/ruum1 is also said to /& well4 ,a ?ird =mula conta9s black seal+-wax dissolv$ 9 ,alcohol4 ,9 ei!r case x w be be/ to apply fir/ a lay] ( cle> v>ni% to ! film1 & aft]w>ds ! black v>ni%1 :i* %\ld comb9e ) ! o!r )\t dissolv+ x4 ,positives :it5$ ) ,bi*loride ( ,m]cury are injur$ by v>ni%+2 !y mu/ !re=e be back$ up ) black velvet1 or ,japan laid ^u ! opposite side ( ! glass4 ,_m pref] tak+ ! picture ^u col\r$ glass1 us+ only a lay] ( cle> v>ni%2 b 9 ?is case ! ,collodion side be+ left upp]mo/1 ! image is necess>ily rev]s$4 ,,section ,,ii4 ,directions = ! use ( ,photographic ,l5ses4 ,^? :o are comp>atively unacqua9t$ ) ! sci5ce ( optics require simple rules to guide !m 9 ! *oice ( a photographic l5s1 & 9 ! prop] mode ( us+ x4 ,two k9ds ( ,a*romatic l5ses are sold1 ! ,portrait l5s & ! ,view l5s2 ! =m] ( :i* is con/ruct$ to admit a l>ge volume ( light1 = ! purpose ( copy+ liv+ objects1 etc4 ,a conv5i5t-siz$ ,cam]a = small portraits is ! half-plate ) a l5s ( ab\t #b-a_/d in*es diamet]1 & giv+ a tol]ably flat field on a surface ( #e in*es by #d4 ,mu* h[ev] 9 ?is respect w dep5d ^u ! quality ( ! glass & also ^u its focal l5g?2 a %ort focus l5s tak+ a picture m quickly1 b giv+ a small] image1 & a field :i* is mi/y t[>ds ! edge4 ,!re is also a great t5d5cy to di/ortion ( ! image 9 portrait l5ses ( l>ge ap]ture & %ort focus1 su* z ^? employ$ = op]at+ 9 a dull light4 ,! :ole plate portrait l5s may be expect$ to cov] #f-a_/b by #d-c_/d in*es1 & has a diamet] ( ab\t #c-a_/d in*es4 ,x w take l>g] pictures ?an ! la/1 b n necess>ily 9 a %ort] "t2 s9ce1 al?\gh ! ap]ture = admitt+ ! light is l>g]1 ! focal l5g? is proportionately great] & ! light less cond5s$4 ,! qu>t]-plate portrait l5s ( #a-a_/d in* diamet] is useful = /]eoscopic subjects & small portraits2 :i* are usually m %>ply def9$ :5 tak5 ) a small l5s4 ,! di/ance at :i* ! ,cam]a is to be plac$ f ! sitt] 9 tak+ a portrait1 w dep5d ^u ! focal l5g? ( ! l5s4 ,! effect ( br++ ! ,cam]a ne>] is to add to ! size ( ! image1 b at ! same "t to increase ! *ance ( di/ortion2 h5ce ) e l5s ( full ap]ture1 !re is a practical limit to ! size ( picture :i* c be tak54 ,:5 x is requir$ to obta9 a l>ge image ) a small l5s1 a /op ) a c5tral ap]ture 7:i* may be readily made ( a piece ( circul> c>dbo>d black5$ ) ,indian ink7 mu/ be plac$ 9 front ( ! l5s4 ,?is w dim9i% ! am\nt ( light1 b w r5d] ! picture m di/9ct t[>ds ! edge1 & br+ a v>iety ( objects at diff]5t di/ances into focus at ! same "t4 ,) a /op atta*$1 ! l5s may also be br\ght ne>] to ! object )\t di/ort+4 ,) reg>d to ?is subject ( ! di/ortion (t5 produc$ by l5ses1 obs]ve p>ticul>ly1 t ) ! portrait comb9ation ( full ap]ture1 & especially :5 ! p[]s ( ! glass are r /ra9$ by its be+ advanc$ too ne> to ! sitt]1--all objects ne> to ! l5s w be magnifi$1 & ^? m remov$ w appe> dim9i%$2 h5ce1 z ! position ( ! sitt] is nev] q v]tical1 ! ,cam]a mu/ be incl9$ a little d[nw>ds1 or ! h&s & feet w be enl>g$1 ! figure 9 fact becom+ pyramidal ) ! base bel[2 :]eas on ! o!r h&1 if ! incl9ation ( ! ,cam]a be too great1 ! head & =ehead w be enl>g$1 & ! figure becomes a pyramid ) ! base above4 ,:5 gr\ps are tak51 arrange ! objects z ne> z possible equidi/ant f ! l5s1 & use a /op if practicable4 ,long-focus l5ses are ! be/ = ?is purpose1 all[+ ! ,photograph to be tak5 fur!r (f1 & giv+ a great] v>iety ( objects 9 focus at ! same "t4 ,portrait l5ses may (t5 be advantage\sly sub/itut$ = ,view l5ses 9 copy+ objects ( /ill life :i* are badly light$4 ,! ap]ture ( ! l5s be+ l>ge1 a ,negative c be obta9$ ) an am\nt ( light :i* w\ld n suffice if a small /op 7 us$4 ,on ! o!r h&1 if ! light be unusually bright1 ! l5s ( full ap]ture is always ! mo/ likely1 f its ext5t ( reflect+ surface1 to produce a mi/y & indi/9ct image4 ,h5ce ! object %\ld be well back$ up ) "s neutral col\r1 or1 if t _c be done1 a pa/ebo>d funnel1 project+ ab\t a foot & a half1 may be fa/5$ 9 front ( ! l5s1 9 ord] to exclude rays ( light n imm$iately conc]n$ 9 ! =mation ( ! image4 ,if ! l5s 7 turn$ t[>ds di/ant objects brightly illum9at$1 & a portion ( sky includ$1 !re w\ld probably be diffus$ light1 & consequ5t fogg+ ( ! plate on ! application ( ! develop]4 ,?is effect w also inv>iably foll[ if ! sun's rays be all[$ to fall directly ^u ! glass4 ,directions = f9d+ ! ,plane at :i* ! ,%>pe/ ,image c be obta9$4--,non-,a*romatic ,l5ses are und]/ood by all to require correction = ! *emical focus2 b x is usually said ( ! comp\nd glasses1 t _! two foci correspond4 ,! amateur is recomm5d$1 9 ord] to avoid disappo9tm5t1 to te/ ! accuracy ( ?is /atem5t1 & also to see t 8 ,cam]a is con/ruct$ ) c>e4 ,to d ?is1 proce$ z foll[s3-- ,fir/ asc]ta9 t ! prep>$ s5sitive plate falls precisely 9 ! plane occupi$ by ! gr\nd glass4 ,susp5d a newspap] or a small engrav+ at ! di/ance ( ab\t ?ree feet f ! ,cam]a1 & focus ! lett]s occupy+ ! c5tre ( ! field2 !n ins]t ! slide1 ) a squ>e ( gr\nd glass sub/itut$ = ! ord9>y plate 7! r\gh surface ( ! glass look+ inw>ds71 & obs]ve if ! lett]s are /ill di/9ct4 ,9 place ( ! gr\nd glass1 a transp>5t plate ) a squ>e ( silv]-pap] :i* has be5 oil$ or wett$1 may be us$1 b ! =m] is pref]able4 ,if ! result ( ?is trial seems to %[ t ! ,cam]a is good1 proce$ to te/ ! correctness ( ! ,l5s4-- ,take a ,positive ,photograph ) ! full ap]ture ( ! portrait ,l5s1 ! c5tral lett]s ( ! newspap] be+ c>efully focuss$ z be=e4 ,!n exam9e at :at "p ( ! plate ! greate/ am\nt ( di/9ctness ( outl9e is to be f\nd4 ,x w sometimes happ51 t :]eas ! exact c5tre 0 focuss$ visually1 ! lett]s on a spot midway betwe5 ! c5tre & edge are ! %>pe/ 9 ! ,photograph4 ,9 t case ! *emical focus is long] ?an ! o!r1 & by a di/ance equival5t to1 b 9 ! opposite direction (1 ! space :i* ! gr\nd glass has to be mov$1 9 ord] to def9e ^? p>ticul> lett]s %>ply to ! eye4 ,:5 ! *emical focus is ! %ort] ( ! two1 ! lett]s 9 ! ,photograph are indi/9ct at e portion ( ! plate2 ! exp]im5t mu/ !re=e be repeat$1 ! l5s be+ %ift$ an eigh? ( an in* or less4 ,inde$ x w be prop] to take _m ,photographs at m9ute v>iations ( focal di/ance be=e ! capabilities ( ! l5s w be fully %[n4 ,! object ( f9d+ ! po9t at :i* ! %>pe/ image is obta9$ w also be assi/$ by plac+ sev]al small figures 9 diff]5t planes & focuss+ ^? 9 ! c5tre4 ,?is be+ done1 if ! m di/ant figures come out di/9ctly 9 ! ,photograph1 ! *emical focus is long] ?an ! ,visual1 or vice v]s :5 ! ne>e/ ones are mo/ %>ply def9$4 ,! ,s+le ,a*romatic ,l5s4--,a useful l5s = l&scape ,photography is "o ( ab\t #c in*es diamet] & #ae in*es focal l5g?1 :i* may be expect$ to cov] a field ( #aj in*es by #h4 ,) ! l5s1 /ops are suppli$ ( v>i\s diamet]s1 ! l>ge/ ( :i* w be useful 9 dull wea!r2 ! small] :5 ! field is requir$ to be r5d]$ %>p to ! v edge4 ,! /op is arrang$ at a c]ta9 di/ance 9 front ( ! l5s1 & mu/ n be mov$4 ,if x 7 br\ght close up to ! glass1 ! field w\ld n be s flat2 ! effect be+ !n ! same z t ( a /op plac$ 9 front ( a ,portrait ,l5s1 viz4 simply to cut (f ! outside portion ( ! glass4#ch #ch ,see ?is subject expla9$ 9 ',photographic ,j\rnal1' vol4 ii4 p4 #acc4 ,9 tak+ ,photographs ( ar*itectural & o!r subjects ) v]tical outl9es1 x is v important to h ! ,cam]a plac$ p]fectly horizontal2 s9ce1 if x be incl9$ ei!r upw>ds or d[nw>ds1 ! p]p5dicul>s w be de/roy$ & ! object w appe> ( a pyramidal =m1 fall+ inw>ds or outw>ds1 z be=e %[n4 ,x is conv5i5t to rule ! gr\nd focuss+ glass ) a numb] ( p>allel l9es 9 bo? directions1 :i* enables ! op]ator at once to see t ! position ( ! in/rum5t is correct4 ,,section ,,iii4 ,mode ( copy+ ,engrav+s1 ,et*+s1 etc4 ,! engrav+ to be ,photograph$ %\ld be remov$ f its frame 7! glass caus+ irregul> reflection7 & susp5d$ v]tically & 9 a rev]s$ position1 9 a good diffus$ light4 ,a black clo? may be plac$ beh9d ! picture ) advantage if any surface likely to reflect light be pres5t$ to ! l5s4 ,! ,cam]a mu/ be fix$ immovably1 s z n to vibrate 9 ! lea/ degree :5 ! cap ( ! l5s is tak5 (f4 ,x %\ld be po9t$ at "r angles to ! picture1 & ! focus det]m9$ 9 ! ord9>y way4 ,ei!r a portrait or a s+le l5s may be us$1 ) a diaphragm suffici5tly small to r5d] ! image di/9ct up to ! edge4 ,x is n desirable to employ too ?9 a ,collodion1 s9ce p]fect opacity ( ! d>ke/ p>ts ( ! ,negative is ess5tial4 ,an old ,collodion conta9+ free ,iod9e is bett] ?an a contractile ,collodion1 z giv+ a m int5se & cle> image4 ,pure ,collodion iodiz$ ) ,iodide ( ,cadmium1 if f\nd want+ 9 int5sity1 may be at once r5d]$ fit = use 9 copy+ engrav+s by add+ ,glycyrrhiz9e 7p4 #bji71 until ! d>k p>ts ( ! negative become v opaque1 & subsequ5tly s(t5+ ! excessive h>dness1 if necess>y1 by dropp+ alcoholic solution ( ,iod9e into ! ,collodion until x rea*es a /raw-yell[ t9t4 ,a second =mula useful 9 iodiz+ ,collodion = a simil> purpose is z foll[s4 ,iodide ( ,potassium #d gra9s4 ,bromide ( ,potassium #a gra94 ,?is1 ) addition ( ,glycyrrhiz9e1 w give a v black image4 ,et*+s1 diagrams1 & draw+s ) p5cil or ink1 )\t mu* middle-t9t1 if on ?9 pap]1 are easily copi$ )\t ! aid ( ! ,cam]a1 by simply lay+ ! sket* ^u a %eet ( ,negative ,pap]1 expos+ = a brief "t to ! light1 & develop+ ) ,gallic ,acid4 ,?is yields a ,negative :i* is employ$ = pr9t+ ,positives 9 ! usual way4 ,full directions on ?is subject w be f\nd 9 ! ,second ,section ( ! foll[+ ,*apt]4 ,a m simple plan1 & "o :i* w succe$ :5 great delicacy is n requir$1 consi/s 9 lay+ ! sket* ^u a %eet ( ,positive pr9t+ pap] 7a highly salt$ pap] w be ! be/1 z giv+ mo/ int5sity7 & expos+ to ! light until a copy is obta9$4 ,all ! details are fai?fully r5d]$ 9 ?is way1 b x is sometimes difficult to obta9 a ,negative suffici5tly black to yield a vigor\s pr9t4 ,,section ,,iv4 ,rules = tak+ ,/]eoscopic ,photographs4 ,b9ocul> pictures ( a l>ge size1 = ! reflect+ ,/]eoscope1 may be tak5 ) an ord9>y ,view l5s ( ab\t #ae in*es focus4 ,! gr\nd glass ( ! ,cam]a hav+ be5 rul$ ) cross l9es 9 ! mann] describ$ at page #bca1 ! position ( "s prom95t object is m>k$ ^u "o ( ! l9es ) a p5cil1 & ! fir/ view is tak54 ,! /& is !n mov$ lat]ally to ! prop] di/ance1 & ! ,cam]a adju/$ to its second position by %ift+ x until ! m>k$ object occupies ! same place z be=e4 ,! di/ance betwe5 ! two positions %\ld be ab\t "o foot :5 ! =egr\nd ( ! picture is tw5ty-five feet f ! in/rum5t1 or f\r feet :5 x is at ?irty or =ty y>ds4 ,b1 z be=e %[n at page #ga1 ?is rule is n to be foll[$ implicitly1 mu* dep5d+ ^u ! "* ( ! picture & ! effect desir$4 ,photographs = ! l5ticul> ,/]eoscope are tak5 ) small l5ses ( ab\t #d-a_/b in*es focus4 ,= portraits1 a ,cam]a may advantage\sly be fitt$ ) two d\ble-comb9ation l5ses1 ( #a-c_/d in*es diamet]1 exactly equal 9 focal l5g? & 9 rapidity ( action4 ,! caps are remov$ simultane\sly1 & ! pictures impress$ at ! same in/ant4 ,! c5tres ( ! l5ses may be sep>at$ by ?ree in*es :5 ! ,cam]a is plac$ at ab\t six feet f ! sitt]1 or f\r in*es :5 ! di/ance is increas$ to eight feet4 ,pictures tak5 ) a b9ocul> ,cam]a ( ?is k9d1 require to be m\nt$ 9 a rev]s$ position to t :i* !y occupy on ! glass3 = s9ce ! image ( ! ,cam]a is inv]t$1 :5 x is turn$ r\nd & made erect1 ! "r-h& picture w necess>ily /& on ! left side1 & vice v]s4 ,mr4 ,latim] ,cl>k has devis$ an arrangem5t = tak+ /]eoscopic pictures ) a s+le ,cam]a1 :i* is exce$+ly +5i\s4 ,its mo/ important feature is a contrivance = rapidly mov+ ! ,cam]a 9 a lat]al direction )\t di/urb+ ! position ( ! image ^u ! gr\nd glass4 ,?is w be und]/ood by a ref]5ce to ! foll[+ woodcut4 ,illu/ration ,a /rongly-fram$ ,cam]a-/& c>ries a flat table1 ab\t #bj in*es wide by #af1 furni%$ ) ! usual adju/m5ts4 ,^u ?is are laid two flat b>s ( wood 9 ! direction ( ! object1 & p>allel1 & ab\t ! wid? ( ! ,cam]a asund]4 ,!y are #ah in*es 9 l5g?2 _! front ends c>ry /\t p9s1 :i* desc5d into ! table & =m c5tres ^u :i* !y turn4 ,_! opposite ends also c>ry simil> p9s1 b ^! are direct$ upw>ds1 & fit into two correspond+ holes 9 ! tail-bo>d ( ! ,cam]a4 ,n[ :5 ! ,cam]a is plac$ ^u ^! p9s1 & mov$ to & fro lat]ally1 ! :ole sy/em exactly resembles ! common p>allel rul]4 ,! two b>s =m ! guides1 & ! ,cam]a1 al?\gh capable ( free lat]al motion1 always ma9ta9s a p>allel position4 ,9 ?is condition ( ?+s x is only suit$ to take /]eoscopic pictures ( an object at an inf9ite di/ance2 b to make x move 9 an arc1 conv]g+ on an object at any ne>] di/ance1 x is only necess>y to make ! two guide-b>s approximate at _! ne>] end s z to conv]ge slightly t[>ds ! object2 & by a few trials "s degree ( conv]g5ce w be readily f\nd at :i* ! image w rema9 z x 7 fix$ on ! focuss+ glass :ile ! ,cam]a is mov$ to & fro4 ,to admit ( ?is adju/m5t1 "o ( ! p9s desc5ds ?r\gh a ,slot 9 ! table & c>ries a clamp+-screw1 by means ( :i* x is readily fix$ 9 any requir$ position4 ,9 ord] h[ev] to r5d] ! motion ( ! ,cam]a smoo!r1 x is advisable n to place x directly ^u ! two guides1 b to int]pose two ?9 slips ( wood1 ly+ across !m at "r angles1 b5ea? ! front & back ( ! ,cam]a respectively 7& :i* may be fix$ to ! ,cam]a if pref]r$71 & to du/ ! surfaces ) p[d]$ soap-/one or ,fr5* *alk4 ,9 addition to ?is arrangem5t = mov+ ! ,cam]a lat]ally1 ! slide = hold+ ! s5sitive plates mu/ be modifi$ f ! common =m4 ,x is oblong 9 %ape1 & be+ ab\t t5 or elev5 in*es long1 requires "s little adaptation to fit x to ! end ( an ord9>y ,cam]a4 ,! glasses are cut to ab\t #f-c_/d in*es by #c-a_/d2 & :5 coat$ ) ,iodide ( ,silv]1 ! two images are impress$ side by side1 ! plate be+ %ift$ lat]ally ab\t #b-a_/b in*es1 at ! same "t & 9 ! same direction z ! ,cam]a itself4 ,! op]ation ( tak+ a portrait is ?us p]=m$4 ,! focus hav+ be5 adju/$ = bo? positions1 & ! ,cam]a & ! slide bo? drawn to ! left-h&1 ! door is rais$ & ! plate expos$2 ! ,cam]a & ! slide are !n %ift$ to ! "r-h&1 & ! plate 9 its new position hav+ be5 aga9 expos$1 ! door is clos$ & ! op]ation complet$4#ci #ci ,see ',photographic ,j\rnal1' vol4 i4 page #ei4 ,pictures tak5 ) ?is in/rum5t d n require to be rev]s$ 9 m\nt+1 ! left picture be+ purposely =m$ on ! "r-h& side ( ! glass4 ,,section ,v4 ,on ! ,photographic del9eation ( ,microscopic objects4 ,_m specim5s ( ,micro-photography :i* h be5 exhibit$ are exce$+ly elaborate & beautiful2 & _! production is n difficult to "o ?or\ghly acqua9t$ ) ! use ( ! ,microscope & ) ! manipulations ( ! ,collodion ,process4 ,x is important h[ev] to possess a good app>atus1 & to h x prop]ly arrang$4 ,! object-glass ( ! ord9>y comp\nd ,microscope is ! only "p actually requir$ 9 ,photography1 b x is useful to reta9 ! body = ! sake ( ! adju/m5ts1 & ! mirrors us$ 9 ! illum9ation4 ,! eye-piece h[ev]1 :i* simply magnifies ! image =m$ by ! object-glass1 is n necess>y1 s9ce ! same effect ( enl>gem5t may be obta9$ by l5g!n+ out ! d>k *amb]1 & ?r[+ ! image fur!r (f4 ,arrangem5t ( ! ,app>atus4--,! ,microscope is plac$ ) its body 9 a horizontal position1 & ! eye-piece be+ remov$1 a tube ( pap]1 prop]ly black5$ 9 ! int]ior1 or l9$ ) black velvet1 is ins]t$ into ! in/rum5t1 to prev5t irregul> reflection ( light f ! sides4 ,a d>k *amb] ( ab\t two feet 9 l5g?1 hav+ at "o end an ap]ture = ! ins]tion ( ! eye-piece end ( ! body1 & at ! o!r a groove = c>ry+ ! slide conta9+ ! s5sitive plate1 is !n atta*$2 c>e be+ tak5 to /op all crevices likely to admit diffus$ light4 ,an ord9>y ,cam]a may be employ$ z ! d>k *amb]1 ! l5s be+ remov$1 & ! body l5g!n$ out if requir$ by a conical tube ( gutta-p]*a1 made to fa/5 into ! flange ( ! l5s 9 front4 ,! :ole app>atus %\ld be plac$ exactly 9 a /raight l9e1 t ! gr\nd glass us$ 9 focuss+ may fall at "r angles to ! axis ( ! ,microscope4 ,! l5g? ( ! *amb]1 measur+ f ! object-glass1 may be f two to ?ree feet1 accord+ to ! size ( image requir$2 b if ext5d$ beyond ?is1 ! p5cil ( light transmitt$ by ! object-glass is diffus$ ov] too l>ge a surface1 & a fa9t & unsatisfactory picture is ! result4 ,! object %\ld be illum9at$ by sunlight if x c be obta9$1 b a bright diffus$ daylight w succe$ ) l[-p[] glasses1 & especially :5 ,positives are tak54 ,employ ! concave mirror = reflect+ ! light on ! object 9 ! latt] case2 b 9 ! =m] ! plane mirror is ! be/1 except ) p[]s exce$+ a qu>t] ( an in*1 & ( l>ge angul> ap]ture4 ,! image ^u ! gr\nd glass %\ld appe> bright & di/9ct1 & ! field ( a circul> =m & ev5ly illum9at$2 :5 ?is is ! case1 all is ready = ins]t+ ! s5sitive plate4 ,! "t ( exposure mu/ be v>i$ accord+ to ! int5sity ( ! light1 ! s5sibility ( ! ,collodion1 & ! degree ( magnify+ p[]2 a few seconds to a m9ute w be ab\t ! extremes2 b m9ute directions are n requir$1 z ! op]ator1 if a good ,photograph]1 w easily asc]ta9 ! prop] "t = expos+ 7see page #bbd74 ,at ?is po9t a difficulty w probably occur f ! plane ( ! *emical focus n correspond+1 z a rule1 ) t ( ! visual focus4 ,?is arises f ! fact t ! object-glasses ( ,microscopes are ov]-correct$ = col\r1 9 ord] to comp5sate = a little *romatic ab]ration 9 ! eye-piece4 ,! violet rays1 9 consequ5ce ( ! ov]-correction1 are project$ beyond ! yell[1 & h5ce ! focus ( *emical action is fur!r f ! glass ?an ! visible image4 ,! all[ance may be made by %ift+ ! s5sitive plate1 or1 :at am\nts to ! same ?+1 by remov+ ! object-glass a little away f ! object ) ! f9e adju/m5t screw2 ! latt] is ! mo/ conv5i5t4 ,! exact di/ance mu/ be det]m9$ by c>eful exp]im5t = ea* glass2 b x is greate/ ) ! l[ p[]s1 & decreases z !y asc5d4 ,mr4 ,%adbolt gives ! foll[+ z a guide3--,an in* & a half objective ( ,smi? & ,beck's make requir$ to be %ift$ #a_/ej? ( an in*1 or two turns ( _! f9e adju/m5t2 a #b_/crds ( an in*1 #a_/bjj? ( an in*1 or half a turn2 & a #d_/aj?s ( an in*1 #a_/ajjj? ( an in*1 or ab\t two divisions ( ! adju/m5t4 ,) ! #a_/d? & high] p[]s1 ! diff]5ce betwe5 ! foci 0 s small z to be practically unimportant4 ,!re is also reason to ?9k t ! k9d ( light employ$ has an influ5ce ^u ! sep>ation ( ! foci4 ,mr4 ,delves f9ds t ) sunlight ! diff]5ce betwe5 !m is v small ev5 ) ! l[ p[]s1 & inappreciable ) ! high]2 :]eas 9 us+ diffus$ daylight :i* has und]gone a previ\s reflection f :ite cl\ds1 x is consid]able4 ,! object-glasses ( ! same mak]1 & p>ticul>ly ^? ( diff]5t mak]s1 also v>y mu*2 s t x w be necess>y to te/ ea* glass sep>ately1 & to regi/] ! all[ance :i* is requir$4 ,hav+ f\nd ! *emical focus1 ! pr9cipal difficulty has be5 ov]come1 & ! rema9+ /eps are ! same 9 e respect z = ord9>y ,collodion ,photographs4 ,to ^? :o _c devote _! "t to ,photography dur+ ! day1 ,mr4 ,%adbolt's obs]vations on ! use ( artificial light may be ( s]vice4 ,he employs ,camph9e1 :i* gives a :it] flame ?an gas1 or a mod]ator lamp2 plac+ ! s\rce ( light 9 ! focus ( a plano-convex l5s ( #b-a_/b to #c in*es diamet] 7! flat side t[>ds ! lamp71 & cond5s+ ! p>allel rays s obta9$ on ! object1 by a second l5s ( ab\t #a-a_/b-;in* diamet] & #c-;in* focus4 ,?is mode ( illum9ation1 be+ feeble 9 *emical rays1 is be/ adapt$ = object-glasses ( l[ p[]4 ,! exposure requir$ to produce a ,negative impression ) ! "o-in* glass may be f ?ree to five m9utes4 ,z ! s5sitive plate w\ld be liable to become dry dur+ t "t1 x is recomm5d$ to coat x ) "s pres]vative solution by ! modes describ$ 9 ! six? ,*apt]4 ,mr4 ,crookes hav+ lately %[n t ! ,bromide ( ,silv] is m s5sitive ?an ! ,iodide to artificial light1 a mixture ( ! two salts may conv5i5tly be us$ 7see pp4 #ff & #bcb74 ,! developm5t may be conduct$ 9 ! same mann] z t = pres]v$ s5sitive plates2 fix+ ) ,cyanide ( ,potassium be=e ! developm5t is fully complete1 if any t5d5cy to fogg+ is obs]v$ 7see page #bbd74 ,! ,rev4 ,w4 ,t[l] ,k+sley has communicat$ a process by :i* v beautiful ,microscopic ,photographs h be5 obta9$4 ,he illum9ates 79 ! abs5ce ( sunlight7 ) ! brilliant light produc$ by ?r[+ a jet ( mix$ ,oxyg5 & ,hydrog5 gases ^u a small cone ( ,lime or ,magnesia4 ,p>ticul> /ress is laid ^u ! object-glass ( ! ,microscope be+ a good "o = ! purpose2 & inde$ all :o h giv5 att5tion to ! subject are agre$ ^u ?is po9t--t !re is a consid]able diff]5ce 9 ! ,photographic value ( objectives1 & ?is indep5d5t ( ! angul> ap]ture ( ! glass4 ,,*apt] ,,iv4 ,,! ,,practical ,,details ,,( ,,photographic ,,pr9t+4 ,?is ,*apt] is divid$ z foll[s3-- ,section ,i4--,! ord9>y direct process ( positive pr9t+4 ,section ,,ii4--,positive pr9t+ by developm5t4 ,section ,,iii4--,! mode ( ton+ ,positives by ,sel d'or4 ,section ,,iv4--,on pr9t+ enl>g$ or r$uc$ ,positives1 transp>5cies1 etc4 ,,section ,i4 ,positive ,pr9t+ by ! direct action ( ,light4 ,?is includes--! prep>ation ( s5sitive pap]1--( fix+ & ton+ ,ba?s1--& ! manipulatory details ( ! process4 ,selection ( ,pap] = ,photographic ,pr9t+4--,! ord9>y v>ieties ( pap] sold 9 comm]ce are n well adapt$ = ! production ( ,positive pr9ts4 ,pap]s are manufactur$ purposely :i* are m smoo? & uni=m 9 texture4 ,_m samples ( ev5 ! f9e/ pap] are h[ev] defective1 & h5ce ea* %eet %\ld be exam9$ sep>ately by hold+ x aga9/ ! light1 & if spots or irregul>ities ( texture are se51 x %\ld be reject$4 ,^! spots usually consi/ ( small p>ticles ( brass or iron1 :i*1 :5 ! pap] is r5d]$ s5sitive1 decompose ! ,nitrate ( ,silv] & leave a circul> m>k v noticeable aft] fix+4 ,! =eign pap]s1 ,fr5* & ,g]man1 are diff]5t f ! ,engli%4 ,!y are por\s & siz$ ) />*1 ! ,engli% be+ siz$ ) gelat9\s animal matt]4 ,9 all cases !re is a diff]5ce 9 smoo?ness betwe5 ! two sides ( ! pap]1 :i* may be detect$ by hold+ ea* %eet 9 su* a mann] t ! light /rikes x at an angle2 ! wrong side is t on :i* d>k wavy b&s1 ( an in* to an in* & a half 9 bread?1 are se51 caus$ by ! /rips ( felt on :i* ! pap] 0 dri$4 ,) mo/ qualities ( pap] no difficulty :atev] w be exp]i5c$ 9 detect+ ! broad & regul> b&s above ref]r$ to2 b :5 !y _c be se51 ! wrong side ( ! %eet may be kn[n by wire m>k+s cross+ ea* o!r1 or if ! pap] be wett$ at ! corn]1 "o side may appe> evid5tly smoo!r ?an ! o!r4 ,,prep>ation ,,( ,,s5sitive ,,pap]4 ,!re are ?ree pr9cipal v>ieties ( s5sitive pap] 9 common use1 viz4 ! ,album9iz$1 ! pla91 & ! ,ammonio-,nitrate pap]4 ,=mula ,i4 ,prep>ation ( ,album9iz$ ,pap]4--,?is includes ! salt+ & album9iz+1 & ! s5sitiz+ ) ,nitrate ( ,silv]4 ,! ,salt+ & ,album9iz+4--,take ( ,*loride ( ,ammonium1 or ,pure ,*loride ( ,sodium #bjj gra9s4 ,wat] #aj fluid ounces4 ,album5 #aj fluid ounces4 ,if di/ill$ wat] _c be procur$1 ra9 wat] or ev5 common spr+ wat]#dj w answ] ! purpose4 ,to obta9 ! ,album51 use new-laid eggs1 & be c>eful t 9 op5+ ! %ell ! yolk is n brok52 ea* egg w yield ab\t "o fluid ounce ( ,album54 #dj ,if ! wat] conta9$ mu* ,sulphate ( ,lime1 x is likely t ! s5sitiv5ess ( ! pap] w\ld be impair$ 7874 ,:5 ! +r$i5ts are mix$1 take a bundle ( quills or a =k1 & beat ! :ole into a p]fect fro?4 ,z ! fro? =ms1 x is to be skimm$ (f & plac$ 9 a flat di% to subside4 ,! success ( ! op]ation dep5ds entirely ^u ! mann] 9 :i* ?is "p ( ! process is conduct$2--if ! ,album5 be n ?or\ghly beat51 flakes ( animal membrane w be left 9 ! liquid1 & w cause /reaks ^u ! pap]4 ,:5 ! fro? has p>tially subsid$1 transf] x to a tall & n>r[ j>1 & all[ to /& = sev]al h\rs1 t ! membran\s %r$s may settle to ! bottom4 ,!n p\r (f ! upp] cle> portion1 :i* is fit = use4 ,album9\s liquids are too glut9\s to run well ?r\gh a pap] filt]1 & are bett] cle>$ by subsid5ce4 ,a m simple plan ?an ! above1 & "o equally efficaci\s1 is to fill a bottle to ab\t ?ree p>ts ) ! salt$ mixture ( ,album5 & wat]1 & to %ake x well = t5 m9utes or a qu>t] ( an h\r until x loses its glut9osity & c be p\r$ out smoo?ly f ! neck ( ! bottle4 ,x is !n to be transf]r$ to an op5 j>1 & all[$ to settle z be=e4 ,! solution prep>$ by ! above directions w conta9 exactly t5 gra9s ( salt to ! ounce1 dissolv$ 9 an equal bulk ( ,album5 & wat]4 ,"s op]ators employ ! ,album5 alone )\t an addition ( wat]2 b ?is commonly gives a highly v>ni%$ appe>ance1 :i* is ?\ght by mo/ to be objectionable4 ,mu* h[ev] w dep5d ^u ! k9d ( pap] :i* is employ$1 c]ta9 v>ieties tak+ m gloss ?an o!rs2 ,papi] ,rive1 = in/ance1 (t5 requires ! ,album5 to be ne>ly or q undilut$4 ,! pr9cipal difficulty 9 ,album9iz+ pap]1 is to avoid ! occurr5ce ( /reaky l9es1 :i*1 :5 ! pap] is r5d]$ s5sitive1 bronze /rongly "u ! influ5ce ( ! light4 ,to avoid !m1 use ! eggs q fre%1 & l[] ! pap] on to ! liquid by "o /eady movem5t2 if a pause be made1 a l9e w probably be =m$4 ,"s pap]s are n readily wett$ by ! ,album51 & :5 su* is ! case1 a few drops ( spiritu\s solution ( bile1 or a fragm5t ( ! prep>$ ,ox-,gall sold by ! arti/s' col\r-m51 w be f\nd a useful adjunct4 ,c>e mu/ be tak5 h[ev] n to add an excess1 or ! ,album5 w be r5d]$ too fluid1 & w s9k into ! pap]1 leav+ no gloss4 ,9 salt+ & album9iz+ ,photographic pap] by ! =mula above giv51 x is f\nd t ea* qu>t]-%eet1 measur+ elev5 in*es by n9e in*es1 removes "o fluid dra*m & a half f ! ba?1 equival5t to ab\t "o gra9 & ?ree-qu>t]s ( salt 7includ+ dropp+s74 ,9 salt+ pla9 pap]1 ea* qu>t]-%eet takes up only "o dra*m2 s t ! glut9\s nature ( ! ,album5 causes a ?ird "p m ( salt to be reta9$ by ! pap]4 ,engli% pap]s are n good = album9iz+2 !y d n take ! ,album5 prop]ly1 & curl up :5 laid ^u ! liquid3 ! process ( ton+ ! pr9ts is also sl[ & t$i\s4 ,! ?9 negative pap] ( ,canson1 ! ,papi] ,rive1 & ,papi] ,saxe1 h succe$$ ) ! writ] bett] ?an ,canson's ,positive pap]1 :i* is (t5 recomm5d$2 !y h a f9] texture1 & give m smoo?ness ( gra94 ,to apply ! ,album51 p\r a portion ( ! solution into a flat di% to ! dep? ( half an in*4 ,!n1 hav+ previ\sly cut ! pap] to ! prop] size1 take a %eet by ! two corn]s1 b5d x into a curv$ =m1 convexity d[nw>ds1 & lay x ^u ! ,album51 ! c5tre "p fir/ t\*+ ! liquid1 & ! corn]s be+ l[]$ gradually4 ,9 ?is way all bubbles ( air wall be pu%$ =w>ds & exclud$4 ,"o side only ( ! pap] is wett$3 ! o!r rema9s dry4 ,all[ ! %eet to re/ ^u ! solution = "o m9ute & a half1 & !n raise x (f1 & p9 x up by two corn]s4 ,if any circul> spots1 free f ,album51 are se51 caus$ by bubbles ( air1 replace ! %eet = ! same l5g? ( "t z at fir/4 ,! pap] mu/ n be all[$ to rema9 ^u ! salt+ ,ba? mu* long] ?an ! "t specifi$1 because ! solution ( ,album5 be+ alkal9e 7z is %[n by ! /rong smell ( ,ammonia evolv$ on ! addition ( ! ,*loride ( ,ammonium7 t5ds to remove ! size f ! pap] & to s9k 9 too deeply2 ?us los+ its surface gloss4 ,album9iz$ pap] w keep a long "t 9 a dry place4 ,"s h recomm5d$ to press x ) a heat$ iron1 9 ord] to coagulate ! lay] ( ,album5 ^u ! surface2 b ?is precaution is unnecess>y1 s9ce ! coagulation is p]fectly effect$ by ! ,nitrate ( ,silv] us$ 9 ! s5sitiz+2 & x is d\btful :e!r a lay] ( dry ,album5 w\ld admit ( coagulation by ! simple application ( a heat$ iron4 ,to r5d] ! pap] s5sitive4--,?is op]ation mu/ be conduct$ by ! light ( a c&le1 or by yell[ light4 ,take ( ,fus$ ,nitrate ( ,silv] #fj gra9s4 ,glacial ,acetic ,acid #a_/c m9im4 ,di/ill$ ,wat] #a ounce4 ,prep>e a suffici5t quantity ( ?is solution1 & lay ! %eet ^u x 9 ! same mann] z be=e4 ,?ree m9utes' contact w be suffici5t ) ! ?9 ,negative pap]1 b if ! ,canson ,positive pap] be us$1 f\r or five m9utes mu/ be all[$ = ! decomposition4 ,! pap]s are rais$ f ! solution by a pair ( bone =ceps or common tweez]s tipp$ ) seal+-wax2 or a p9 may be us$ to lift up ! corn]1 :i* is !n tak5 by ! f+] & ?umb & all[$ to dra9 a little be=e aga9 putt+ 9 ! p91 o!rwise a :ite m>k w be produc$ ^u ! pap]1 f decomposition ( ! ,nitrate ( ,silv]4 ,:5 ! %eet is hung up1 a small /rip ( blott+-pap] susp5d$ f ! l[] edge ( ! pap] w s]ve to dra9 (f ! la/ drop ( liquid4 ,a ,ba? prep>$ by ! above =mula is /rong] ?an is really necess>y4 ,=ty gra9s ( ,nitrate to ! ounce ( wat] is abundantly suffici5t if ! sample be pure2 b x mu/ be borne 9 m9d t ! /r5g? ( ! ,ba? dim9i%es rapidly by use1 & h5ce1 :5 ! pr9ts beg9 to be want+ 9 vig\r1 ) pale %ad[s & p]haps a spott$ appe>ance1 an addition ( ,nitrate ( ,silv] mu/ be made4 ,fus$ ,nitrate ( ,silv] is recomm5d$ 9 pref]5ce to ! cry/alliz$ ,nitrate1 on acc\nt ( ! latt] be+ occasionally contam9at$ ) an impurity allud$ to at page #aja4 ,?is :5 pres5t w be likely to r$d5 ! pictures & to int]f]e ) ! rapidity ( bronz+4 ,! solution ( ,nitrate ( ,silv] becomes aft] a "t discol\r$ by ! ,album51 b may be us$ = s5sitiz+ until x is ne>ly black4 ,! col\r c be remov$ by ,animal ,*>coal1#da b a bett] plan is to use ! kaol91 or pure :ite *9a clay4 ,?is sub/ance (t5 conta9s ,c>bonate ( ,lime1 & eff]vesces ) acids3 x mu/ 9 su* a case be purifi$ by wa%+ 9 v9eg>1 or ! ,ba? w become alkal9e1 & dissolve (f ! ,album54 ,x has be5 /at$ t an addition ( ,alcohol to ! ,nitrate ,ba? prev5ts x discol\r+ ) ,album54 #da ,common ,animal ,*>coal conta9s ,c>bonate & ,phosphate ( ,lime1 ! =m] ( :i* r5d]s ! ,nitrate ( ,silv] alkal9e2 purifi$ ,animal ,*>coal is usually acid f ,hydro*loric ,acid4 ,s5sitive album9iz$ pap] w usually keep = sev]al days1 if protect$ f ! light1 b aft]w>ds turns yell[ f p>tial decomposition4 ,=mula ,,ii4 ,prep>ation ( pla9 pap]4--,take ( ,*loride ( ,ammonium or ,sodium #afj gra9s4 ,purifi$ ,gelat9e #bj gra9s4 ,icel& ,moss#db #fj gra9s4 ,wat] #bj ounces4 #db ,icel& ,moss is recomm5d$ because ! writ] f9ds t ,positives s pr9t$ /& ! action ( de/ructive te/s bett] ?an pr9ts on pla9 pap]1 & equal to pr9ts ^u ,ammonio-,nitrate pap]4 ,p\r boil+ wat] ^u ! ,moss & ,gelat9e & /ir until ! latt] is dissolv$1 !n cov] ! vessel & set aside until cold2 add ! salt1 & /ra94 ,use ,papi] ,saxe or ,t[good's pap]1#dc float$ ^u ! salt+ ,ba? 9 ! same mann] z direct$ = ,album5 at p4 #bdc4 #dc ,! writ] does n recomm5d ! ,positive pap] ( ,de ,canson1 hav+ notic$ t pr9ts ^u t pap] d n )/& ! action ( sulphurett+ ag5ts s well z o!rs 7874 ,r5d] s5sitive by float+ = two or ?ree m9utes ^u a solution ( ,nitrate ( ,silv]1 #dj gra9s to ! ounce4 ,?irty gra9s to ! ounce1 or less1 w be suffici5t if ! sample be pure2 b 9 t case occasional additions ( fre% ,nitrate ( ,silv] mu/ be made1 z ! ,ba? loses /r5g?4 ,a second ,=mula = pla9 pap]4--,take ( ,*loride ( ,ammonium #bjj gra9s4 ,citrate ( ,soda#dd #bjj ,gelat9e #bj ,wat] #bj fluid ounces4 #dd ,?is salt may be obta9$ at ! op]ative *emi/s2 or x may be prep>$ extemporane\sly by neutraliz+ #aab gra9s ( pure ,citric ,acid1 free f ,t>t>ic ,acid1 ) #acc gra9s ( ! dri$ ,bic>bonate or ,sesquic>bonate ( ,soda1 us$ = eff]vesc+ draughts4 ,if ,t[good's or any ,engli% pap] be us$1 ! ,citric ,acid1 ,c>bonate ( ,soda1 & ,gelat9e may be omitt$4 ,) a =eign pap] ! ,citrate t5ds to give a purple tone to ! ,positive1 :5 ton$ by ,sel d'or1 b ! gold ton+ ,ba? mu/ be 9 active ord]1 or ! pr9ts w be too r$4 ,! ,citric ,acid also %\ld n be 9 excess ov] ! alkal9e ,c>bonate4 ,r5d] s5sitive by float+ = ?ree m9utes ^u a ,nitrate ,ba? ( sixty gra9s to ! ounce ( wat]4 ,=mula ,,iii4 ,ammonio-,nitrate ,pap]4--,?is is always prep>$ )\t ,album51 :i* is dissolv$ by ,ammonio-,nitrate ( ,silv]4 ,take ( ,*loride ( ,ammonium #ajj gra9s4 ,citrate ( ,soda #bjj ,gelat9e #bj ,wat] #bj fluid ounces4 ,dissolve ! ,gelat9e by ! aid ( heat2 add ! o!r +r$i5ts1 & filt]4 ,! solution _c be kept long] ?an two or ?ree weeks )\t becom+ m\ldy4 ,! ,saxony pap]1 or ,t[good's ,engli% pap]1 may be employ$2 ! ,gelat9e & ,citrate be+ reta9$ or omitt$1 accord+ to ! ta/e ( ! op]ator & ! mode ( ton+ :i* is adopt$4 ,r5d] s5sitive by a solution ( ,ammonio-,nitrate ( ,silv]1 #fj gra9s to ! ounce ( wat]1 :i* is prep>$ z foll[s3-- ,dissolve ! ,nitrate ( ,silv] 9 "o-half ( ! total quantity ( wat]4 ,!n take a pure solution ( ,ammonia & drop x 9 c>efully1 /irr+ mean:ile ) a glass rod4 ,a br[n precipitate ( ,oxide ( ,silv] fir/ =ms1 b on ! addition ( m ,ammonia x is re-dissolv$4#de ,:5 ! liquid appe>s to be cle>+ up1 add ! ,ammonia v cauti\sly1 s z n to incur an excess4 ,9 ord] /ill fur!r to secure ! abs5ce ( free ,ammonia1 x is usual to direct1 t :5 ! liquid becomes p]fectly cle>1 a drop or two ( solution ( ,nitrate ( ,silv] %\ld be add$ until a slight turbidity is aga9 produc$4 ,la/ly1 dilute ) wat] to ! prop] bulk4 ,if ! cry/als ( ,nitrate ( ,silv] employ$ conta9 a l>ge excess ( free ,nitric ,acid1 no precipitate w be =m$ on ! fir/ addition ( ,ammonia4 ,! free ,nitric ,acid1 produc+ ,nitrate ( ,ammonia ) ! alkali1 keeps ! ,oxide ( ,silv] 9 solution4 ,?is cause ( error h[ev] is n likely to happ5 frequ5tly1 s9ce ! am\nt ( ,nitrate ( ,ammonia requir$ to prev5t all precipitation w\ld be consid]able4 ,f ! same reason1 viz4 ! pres5ce ( ,nitrate ( ,ammonia1 x is (t5 useless to attempt to conv]t an old ,nitrate ,ba? already us$ = s5sitiz+1 into ,ammonio-,nitrate4 #de ,if ! excess ( ,ammonia does n readily dissolve x1 probably ! ,nitrate ( ,silv] is impure4 ,ammonio-,nitrate ( ,silv] %\ld be kept 9 a d>k place1 be+ m prone to r$uction ?an ! ,nitrate ( ,silv]4 ,s5sitiz+ pap] ) ,ammonio-,nitrate4--,x is n usual to float ! pap] :51 ! ,ammonio-,nitrate ( ,silv] is us$4 ,if a ba? ( ?is liquid 7 employ$1 x w\ld n only become quickly discol\r$ by ! action ( organic matt] dissolv$ out ( ! pap]s1 b w\ld soon conta9 abundance ( free ,ammonia 7see ! ,vocabul>y1 ,"p ,,iii41 art4 ,ammonio-,nitrate72 & an excess ( ,ammonia 9 ! liquid produces an injuri\s effect by dissolv+ away ! s5sitive ,*loride ( ,silv]4 ,! ,ammonio-,nitrate is !re=e appli$ ) a glass rod1 or by bru%+1 & 9 nei!r case is any ( ! liquid :i* has once t\*$ ! pap] all[$ to return into ! bottle4 ,bru%es are manufactur$ purposely = apply+ ,silv] solutions1 b ! hair is soon de/roy$ unless ! bru% be kept scrupul\sly clean4 ,lay ! salt$ %eet ^u blott+-pap]1 & wet x ?or\ghly by draw+ ! bru% fir/ l5g?ways & !n across4 ,all[ x to rema9 flat = a m9ute or s1 9 ord] t a suffici5t quantity ( ! solution may be absorb$ 7y w see :5 x is ev5ly wet by look+ along ! surface71 & !n p9 up by ! corn] 9 ! usual way4 ,if1 on dry+1 :ite l9es appe> at ! po9ts la/ t\*$ by ! bru%1 x is probable t ! ,ammonio-,nitrate conta9s free ,ammonia4 ,! employm5t ( a glass rod is a v simple & economical mode ( apply+ ,silv] solutions4 ,procure a flat piece ( bo>d some:at small] ?an ! %eet to be op]at$ on1 & hav+ turn$ ov] ! edges ( ! pap]1 secure !m ) a p94 ,next br+ ! bo>d ne> to ! corn] ( ! table1 & lay+ ! glass rod along ! edge ( ! pap]1 all[ ! fluid to drop into ! groove s =m$2 !n c>ry ! rod directly across ! %eet1 :5 an ev5 wave ( fluid w be spread ov] ! surface4 ,a pipette made ( glass tub+1 :5 dipp$ into ! bottle & ! upp] end clos$ ) ! f+]1 w )draw z mu* ( ! ,ammonio-,nitrate z is requir$2 & if a scrat* be made ^u ! tube at a po9t correspond+ to #cj or #dj m9ims1 x w be f\nd suffici5t = a qu>t] %eet ( ! ,papi] ,saxe4 ,ammonio-,nitrate pap]1 h[ev] prep>$1 _c be kept _m h\rs )\t becom+ br[n & discol\r$4 ,use ( a solution ( ,oxide ( ,silv] 9 ,nitrate ( ,ammonia4--,! great objection to ! use ( ,ammonio-,nitrate ( ,silv] is ! decomposition :i* x sometimes exp]i5ces by keep+1 metallic ,silv] sep>at+ & ,ammonia be+ set free4 ,to obviate ?is lib]ation ( ,ammonia1 ! ,au?or employs ,nitrate ( ,ammonia z ! solv5t = ! ,oxide ( ,silv]4 ,! solution is prep>$ z foll[s3--,dissolve #fj gra9s ( ,nitrate ( ,silv] 9 half an ounce ( wat]1 & drop 9 ,ammonia until ! precipitat$ ,oxide ( ,silv] is exactly re-dissolv$4 ,!n divide ?is solution ( ,ammonio-,nitrate ( ,silv] into two equal p>ts1 to "o ( :i* add ,nitric ,acid cauti\sly1 until a piece ( imm]s$ litmus-pap] is r$d5$ by an excess ( ! acid2 !n mix ! two toge!r1 fill up to "o ounce ) wat]1 & filt] f ! milky deposit ( ,*loride or ,c>bonate ( ,silv]1 if any be =m$4 ,?is solution ( ,oxide ( ,silv] 9 ,nitrate ( ,ammonia appe>s to possess all ! advantages ( ! ,ammonio-,nitrate )\t ! inconv5i5ce ( lib]at+ s mu* free ,ammonia ^u ! surface ( ! s5sitive %eets4 ,h9ts 9 select+ f ! above ,=mul4--,album9iz$ pap] is ! mo/ simple & g5]ally useful2 x is well fitt$ = small portraits & /]eoscopic ,photographs4 ,! ,ammonio-,nitrate ,process requires m exp]i5ce1 b gives excell5t results :5 black tones are requir$3 x may be us$ = l>g] portraits1 engrav+s1 etc4 ,pla9 pap] r5d]$ s5sitive by float+ ^u a ,ba? ( ,nitrate ( ,silv] is easi] ( manipulation ?an ! ,ammonio-,nitrate1 & w be f\nd to be bett] adapt$ = ton+ by ! ,sel d'or ,ba? 7p4 #bfg7 ?an ! ,album9iz$ ,pap]4 ,,prep>ation ,,( ,,! ,,fix+ ,,& ,,ton+ ,,ba?4 ,take ( ,*loride ( ,gold #d gra9s4 ,nitrate ( ,silv] #af gra9s4 ,hyposulphite ( ,soda#df #d ounces4 ,wat] #h fluid ounces4 #df ,! common k9d ( ,hyposulphite ( ,soda occurr+ 9 yell[ & discol\r$ masses1 is too impure = use 9 ,photography1 & requires re-cry/allization4 ,dissolve ! ,hyposulphite ( ,soda 9 f\r ounces ( ! wat]1 ! ,*loride ( ,gold 9 ?ree ounces1 ! ,nitrate ( ,silv] 9 ! rema9+ ounce2 !n p\r ! dilut$ ,*loride by degrees into ! ,hyposulphite1 /irr+ ) a glass rod2 & aft]w>ds ! ,nitrate ( ,silv] 9 ! same way4 ,?is ord] ( mix+ ! solutions is to be /rictly obs]v$3 if x 7 rev]s$1 ! ,hyposulphite ( ,soda be+ add$ to ! ,*loride ( ,gold1 ! result w\ld be ! r$uction ( ,metallic ,gold2 ,hyposulphite ( ,gold1 :i* is =m$1 be+ an un/able sub/ance1 & n capable ( exi/+ 9 contact ) unalt]$ ,*loride ( ,gold4 ,if h[ev] x be dissolv$ by ,hyposulphite ( ,soda imm$iately on its =mation1 x is r5d]$ m p]man5t1 by conv]sion into a d\ble salt ( ,soda & ,gold4 ,9 place ( ,nitrate ( ,silv]1 recomm5d$ 9 ! =mula1 ,*loride ( ,silv] may be us$1 b n ,iodide ( ,silv]1 z ! =mation ( ,iodide ( ,sodium w\ld be objectionable 7p4 #acf74 ,= ! same reason x is bett] n to add any "p ( ! ,hyposulphite ,ba? us$ = fix+ ,negatives1 to ! ,positive col\r+ solution4 ,?is ton+ ,ba? is n to be employ$ imm$iately aft] mix+1 b %\ld be set aside until a portion ( ,sulphur 7produc$ by free ,hydro*loric ,acid1 & ,tetra?ionate ( ,soda react+ ^u ! ,hyposulphite7 has subsid$4 ,x w be v active at ! expiration ( a few days or a week2 b ^u keep+ = a long] "t1 loses mu* ( its efficacy by a process ( spontane\s *ange4 ,! imm]sion ( pr9ts also less5s ! quantity ( ,gold2 & h5ce1 :5 ! ,ba? beg9s to "w sl[ly1 m ( ! ,*loride mu/ be add$1 ! ,sulphur be+ all[$ to deposit z be=e4 ,filtration ?r\gh blott+-pap] w n be requir$4 ,! writ] f9ds t aft] a c]ta9 "t1 :5 ! ,ba? has be5 long us$1 & organic matt]s1 ,album51 etc41 h accumulat$ 9 x1 x is bett]1 & m economical1 to ?r[ away :at rema9s1 & to prep>e a new solution4 ,! addition ( ,*loride ( ,gold to an old ,ba? w n always make x "w z quickly z "o rec5tly mix$4 ,,! ,,manipulatory ,,details ,,( ,,photographic ,,pr9t+4 ,^! include--! exposure to light1 or pr9t+ prop]ly s call$2 ! fix+ & ton+2 & ! wa%+1 dry+1 & m\nt+ ( ! pro(4 ,! ,exposure to ,light4--,= ?is purpose rev]s+ frames are sold1 :i* admit ( be+ op5$ at ! back1 9 ord] to exam9e ! progress ( ! d>k5+ by light1 )\t produc+ any di/urbance ( position4 ,simple squ>es ( glass h[ev] succe$ equally well1 :5 a little exp]i5ce has be5 acquir$4 ,!y may be held toge!r by ! wood5 clips sold at ! ,am]ican w>eh\ses at "o %ill+ p] doz54 ,! l[] plate %\ld be cov]$ ) black clo? or velvet4 ,suppos+ ! frame to be employ$1 ! %utt] at ! back is remov$1 & ! ,negative laid flat ^u ! glass1 ,collodion side upp]mo/4 ,a %eet ( s5sitive pap] is !n plac$ ^u ! ,negative1 s5sitive side d[nw>ds1 & ! :ole tightly compress$ by replac+ & bolt+ d[n ! %utt]4 ,?is op]ation may be conduct$ 9 ! d>k room2 b unless ! light be /rong1 su* a precaution w n be requir$4 ,! "t ( exposure to light v>ies mu* ) ! d5sity ( ! ,negative & ! p[] ( ! act9ic rays1 z influ5c$ by ! season ( ! ye> & o!r obvi\s consid]ations4 ,z a g5]al rule1 ! be/ ,negatives pr9t sl[ly2 :]eas ,negatives :i* h be5 "u-expos$ & "u-develop$ pr9t m quickly4 ,9 ! e>ly spr+ or summ]1 :5 ! light is p[]ful1 probably ab\t t5 to fifte5 m9utes w be requir$2 b f ?ree-qu>t]s ( an h\r to an h\r & a half may be all[$ 9 ! w9t] mon?s1 ev5 9 ! direct rays ( ! sun4 ,x is always easy to judge ( ! l5g? ( "t :i* w be suffici5t1 by expos+ a small slip ( ! s5sitive pap]1 un%ield$1 to ! sun's rays1 & obs]v+ h[ long x takes to rea* ! copp]y /age ( r$uction4 ,:atev] t "t may be1 ne>ly ! same w be occupi$ 9 ! pr9t+1 if ! ,negative be a good "o4 ,:5 ! d>k5+ ( ! pap] appe>s to h proce$$ to a consid]able ext5t1 ! frame is to be tak5 9 & ! picture exam9$4 ,if squ>es ( plate glass are us$ to keep ! ,negative & s5sitive pap] 9 contact1 "s difficulty may be exp]i5c$ at fir/ 9 return+ x precisely to its =m] position aft] ! exam9ation is complete1 b ?is w easily be ov]come by practice4 ,! f+] & ?umb %\ld be fix$ on ! l[] corn]s or edge1 & ! plate rais$ ev5ly & quickly4 ,if ! exposure to light has be5 suffici5tly long1 ! pr9t appe>s slightly d>k] ?an x is int5d$ to rema94 ,! ton+ ,ba? dissolves away ! light] %ades1 & r$uces ! int5sity1 = :i* all[ance is made 9 ! exposure to light4 ,a little exp]i5ce soon tea*es :at is ! prop] po9t2 b mu* w dep5d ^u ! /ate ( ! ton+ ,ba?2 & album9iz$ pap] w require to be pr9t$ some:at m deeply ?an pla9 pap]4 ,if1 on removal f ! pr9t+-frame1 a peculi> spott$ appe>ance is se51 produc$ by unequal d>k5+ ( ! ,*loride ( ,silv]1 ei!r ! ,nitrate ,ba? is too weak1 ! %eet remov$ f its surface too spe$ily1 or ! pap] is ( inf]ior quality4 ,on ! o!r h&1 if ! g5]al aspect ( ! pr9t is a ri* *ocolate-br[n 9 ! case ( ,album51 a d>k slate-blue ) ,ammonio-,nitrate ,pap]1 or a r$di% purple ) pap] prep>$ ) ,*loride & ,citrate ( ,silv]1 probably ! subsequ5t p>ts ( ! process w proce$ well4 ,if1 9 ! exposure to light1 ! %ad[s ( ! pro( become v decid$ly copp]y be=e ! lights are suffici5tly pr9t$1 ! ,negative is 9 fault4 ,ammonio-,nitrate pap] highly salt$ is p>ticul>ly liable to ?is fault ( excess ( r$uction1 & especially s if ! light be p[]ful2 h5ce x is be/1 9 ! summ] mon?s1 n to pr9t by ! direct rays ( ! ,sun4 ,?is po9t is important also1 because ! excessive heat ( ! ,sun's rays (t5 cracks ! glasses by unequal expansion1 & glues ! ,negative firmly d[n to ! s5sitive pap]4 ,an exception h[ev] may be made 9 ! case ( ,negatives ( great int5sity2 :i* are pr9t$ mo/ successfully ^u1 a weakly s5sitiz$ pap] 7p4 #abd7 expos$ to ! full rays ( ! ,sun2 a feeble light n fully p5etrat+ ! d>k p>ts4 ,! fix+ & ton+ ( ! pro(4--,no injury results f po/pon+ ?is "p ( ! process = _m h\rs1 provid$ ! pr9t be kept 9 a d>k place4 ,! mode (t5 foll[$ is to imm]se ! ,positive 9 ! ,hyposulphite ,ba? 9 ! /ate 9 :i* x comes f ! pr9t+-frame2 mov+ x ab\t 9 ! liquid 9 ord] to displace air-bubbles1 :i*1 if all[$ to rema91 produce spots4 ,b ! ,au?or1 = reasons giv5 9 ! fir/ "p ( ! ,"w 7pp4 #abi & #afe71 recomm5ds t ! pr9t %\ld fir/ be wa%$ 9 common wat] until ! soluble ,nitrate ( ,silv] has be5 remov$4#dg ,?is is kn[n to be ! case :5 ! liquid fl[s away cle>2 ! fir/ milk9ess be+ caus$ by ! soluble ,c>bonates & ,*lorides 9 ! wat] precipitat+ ! ,nitrate ( ,silv]4 ,great] security is ?us af=d$ t ! pr9t w be ton$ 9 a really p]man5t mann]1 s9ce aft] remov+ ! ,nitrate ( ,silv] f ! pro(1 ! ,ba? does n "w quickly unless ! supply ( ,gold be well ma9ta9$4 #dg ,?is wat] mu/ be free f ,hyposulphite ( ,soda1 or ! pr9t w become discol\r$4 ,imm$iately on com+ 9 contact ) ! ,hyposulphite ( ,soda 9 ! fix+ & ton+ ,ba?1 ! *ocolate br[n or violet t9t ( ! ,positive disappe>s1 & leaves ! image ( a r$ tone4 ,album5 pro(s become brick-r$2 ,ammonio-,nitrate a sepia or br[n-black4 ,if ! col\r is unusually pale at ?is /age1 probably ! ,silv] ,ba? is too weak1 or ! quantity ( ,*loride ( ,ammonium or ,sodium insuffici5t4 ,aft] ! pr9t has be5 ?or\ghly r$d5$1 ! ton+ action beg9s1 & mu/ be cont9u$ until ! desir$ effect is obta9$4 ,?is may happ5 9 f t5 m9utes to a qu>t] ( an h\r1 if ! solution is 9 good work+ ord] & ! !rmomet] at #fj2 b mu* dep5ds ^u ! temp]ature1 & ! activity ( ! ,ba?4 ,engli% pap]s1 & especially ! same prep>$ ) ,album51 tone m sl[ly ?an =eign pap]s pla9 salt$4 ,! br[n & purple t9ts are an e>li] /age ( coloration ?an ! black tones1 & !re=e ! latt] require m "t4 ,x mu/ be borne 9 m9d h[ev] t prolong$ imm]sion 9 ! ,ba? is fav\rable to sulphuration & yell[ness2 t5d+ also to r5d] ! image un/able & liable to fade 9 ! half-tones4 ,?is fad+ may n be se5 decid$ly :il/ ! pr9t is 9 ! ,ba?1 b w %[ itself 9 ! aft]-processes ( wa%+ & dry+4 ,! ultimate col\r ( ! ,pr9t w v>y mu* ) ! d5sity ( ! ,negative & ! "* ( ! subject2 copies ( l9e engrav+s1 hav+ b little half-tone1 are easily obta9$ ( a d>k %ade resembl+ ! orig9al impression4 ,"s advise t on removal f ! ton+ ,ba? ! ,pr9t %\ld be soak$ 9 new ,hyposulphite = t5 m9utes1 to complete ! fixation2 b ?is precaution is n requir$ ) a ,ba? ( ! /r5g? giv5 9 ! =mula4 ,an analysis ( an old ,ba? :i* _h be5 ext5sively us$1 indicat$ only t5 gra9s ( ,hyposulphite ( ,silv] to ! ounce1 s t x 0 f> f saturat$4 ,! occasional addition ( fre% cry/als ( ,hyposulphite ( ,soda to keep up ! /r5g? ( ! ,ba?1 is useful1 ! exact quantity add$ n be+ mat]ial4 ,! wa%+1 dry+1 & m\nt+ ( ! ,positive ,pro(s4--,x is ess5tial to wa% out e trace ( ,hyposulphite ( ,soda f ! ,pr9t if x is to be pres]v$ f fad+1 & to d ?is prop]ly requires consid]able c>e4 ,always wa% ) runn+ wat] :5 x c be obta9$1 & *oose a l>ge %all[ vessel expos+ a consid]able surface 9 pref]5ce to "o ( less] diamet]4 ,a con/ant dribbl+ ( wat] mu/ be ma9ta9$ = f\r or five h\rs1 & ! pr9ts %\ld n lie toge!r too closely1 or ! wat] does n f9d its way betwe5 !m1 7see ! rem>ks at p4 #afb74 ,:5 runn+ wat] _c be obta9$1 proce$ z foll[s3--fir/ wa% ! ,pr9ts g5tly1 to remove ! great] "p ( ! ,hyposulphite solution4 ,!n transf] !m to a l>ge %all[ pan1 9 :i* may be plac$ z _m ,pr9ts z x w conv5i5tly hold4 ,leave !m 9 = ab\t a qu>t] ( an h\r1 ) occasional movem5t1 & !n p\r (f ! wat] q dry4 ,?is po9t is important1 viz4 to dra9 (f ! la/ portion ( liquid completely be=e add+ fre% wat]4 ,repeat ! process ( *ang+ at lea/ five or six times1 or m1 accord+ to ! bulk ( wat]1 numb] ( ,pr9ts1 & degree ( att5tion paid to !m4 ,la/ly1 proce$ to remove ! size f ! ,pr9t by imm]sion 9 boil+ wat]4#dh ,?is process w give "s idea ( ! p]man5cy ( ! t9ts1 s9ce1 if !y become dull & r$1 & d n d>k5 on dry+1 ! ,pr9t is probably ton$ )\t ,gold4 ,ammonio-,nitrate & pla9 pap] ,pr9ts prep>$ on =eign pap]s by ! modes describ$ 9 ?is ,"w1 may be expect$ to /& ! te/ ( boil+ wat]2 ,album5 ,pr9ts & ,positives on ,engli% pap] are a little r$d5$1 al?\gh n to an objectionable degree4 #dh ,! ,pr9t mu/ be well wa%$ 9 cold wat]1 to remove ! ,hyposulphite1 be=e us+ ! hot wat]2 or ! half-tones w be liable to be d>k5$1 or *ang$ to incipi5t yell[ness1 by sulphuration4 ,?is po9t is important z reg>ds ! p]man5cy4 ,! size may also be effectually remov$ f ! ,pr9t by ! common ,c>bonate ( ,soda us$ 9 wa%+1 al?\gh ! =m] process is recomm5d$ z ! mo/ secure4 ,dissolve ab\t a h&ful ( ! ,soda 9 a p9t ( wat]1 & :5 ! milky deposit1 if any occurs1 has subsid$1 imm]se ! wa%$ ,positives = tw5ty m9utes or half an h\r4 ,! ,soda r5d]s ! pap] q por\s1 b produces no alt]ation ( t9t4 ,if ! process be prop]ly p]=m$1 ink w run 9 attempt+ to write ^u ! back ( ! f9i%$ picture4 ,aft] removal f ! ,soda ,ba? a second wa%+ w be requir$1 b ! "t ( ! fir/ wa%+ may be proportionally %ort5$4 ,"h a difficulty w occur ) _m k9ds ( wat]2 ! ,c>bonate ( ,soda precipitat+ ,c>bonate ( ,lime1 9 ! =m ( a :ite p[d] :i* obscures ! picture4 ,to obviate ?is1 use ra9 wat] until ! great] "p ( ! alkal9e salt has be5 remov$1 & d n all[ a /ation>y lay] ( liquid to re/ too long ^u ! ,pr9t4 ,! ,new ,riv] wat] suppli$ to _m p>ts ( ,london1 be+ comp>atively s(t1 answ]s p]fectly1 & produces no :ite deposit1 if ! pro(s are mov$ ab\t occasionally4 ,:5 ! ,pr9ts h be5 ?or\ghly wa%$1 blot !m (f betwe5 %eets ( por\s pap] & hang up to dry4 ,"s press !m ) a hot iron1 :i* d>k5s ! col\r slightly1 b does s 9 an injuri\s mann] :5 ,hyposulphite ( ,soda is left 9 ! pap]4 ,album5 pro(s :5 dry are suffici5tly bright )\t fur!r treatm5t2 b 9 ! case ( pla9 pap]1 salt$ simply1 ! effect is improv$ by lay+ ! ,pr9t face d[nw>ds ^u a squ>e ( plate-glass & rubb+ ! back ) an agate burni%]1 sold at ! arti/s' col\r-m5's4 ,?is h>d5s ! gra9 ( ! pap] & br+s out ! details ( ! picture4 ,hot-press+ has a simil> effect & is (t5 employ$4 ,m\nt ! pro(s ) a solution ( ,gelat9e 9 hot wat]1 fre%ly made2 ! be/ ,scot* glue answ]s well4 ,gum wat]1 prep>$ f ! f9e/ comm]cial gum1 & free f acidity1 may also be us$1 b x %\ld be made v ?ick1 t x may n s9k into ! pap]1 nor produce an unpleasant cockl+ up ( ! c>dbo>d1 :i* is caus$ by ! damp & exp&$ pr9t contract+ z x dries4 ,ca\t*\c dissolv$ 9 m9]al ,naph?a to ! consi/5ce ( ?ick glue or gold-beat]s' size1 is employ$ by _m = m\nt+ ,photographic ,pr9ts2 x may be obta9$ at ! v>ni% %ops1 & is sold 9 t9 boxes4 ,! mode ( us+ x is z foll[s3--) a broad bru% made ( /iff bri/les1 apply ! cem5t to ! back ( ! picture2 !n take a /rip ( glass ) a /raight edge1 & by draw+ x across ! pap]1 scrape (f z mu* z possible ( ! excess4 ,! pr9t w !n be f\nd to adh]e v readily to ! c>dbo>d1 )\t caus+ expansion or cockl+2 & any portion ( ! cem5t :i* oozes out dur+ ! press+ may1 :5 dry1 be remov$ ) a p5knife )\t leav+ a /a94 ,,rem>ks ,,^u ,,! ,,want ,,( ,,correspond5ce ,,betwe5 ,,! ,,=mula ,,( ,,diff]5t ,,op]ators4 ,! =mul = ,positive pr9t+ giv5 9 ! works on practical ,photography exhibit great v>iety2 & x has be5 propos$ to attempt to r$uce !m to m uni=m proportions4 ,?is _c h[ev] easily be done1 bo? on acc\nt ( ! diff]5ce 9 ! /ructure & prep>ation ( ! v>i\s ,photographic pap]s1 & also because ! mode ( apply+ ! solutions is n always ! same4 ,take z an illu/ration ! foll[+ process1 :i* has long be5 recomm5d$ = its simplicity1 & :i* is 9 e respect a good "o3--,dissolve #dj gra9s ( ,*loride ( ,ammonium 9 #bj ounces ( ,di/ill$ ,wat]1 & imm]se ab\t a doz5 %eets ( ,t[good's ,positive pap]1 remov+ air-bubbles ) a camels'-hair bru%4 ,:5 ! la/ %eet has be5 plac$ 9 ! liquid1 turn ! bat* ov] & take !m out "o by "o1 s t ea* %eet1 rema9+ 9 ! liquid at lea/ t5 m9utes1 may be ?or\ghly saturat$4 ,:5 dry1 excite by bru%+ ) a #dj or #fj-;gra9 solution ( ,ammonio-,nitrate ( ,silv] 9 ! usual way4 ,n[ ?is =mula conta9s less ?an "o-fif? ( ! am\nt ( salt (t5 employ$1 & if a ?ick =eign pap] siz$ ) />*1 su* z ,canson's ,positive1 7 float$ ^u su* a salt+ ,ba?1 x w\ld be difficult to obta9 a good picture4 ,by imm]s+ h[ev] a pap] siz$ ) ,gelat9e l ! "o recomm5d$1 a mu* l>g] quantity ( salt is reta9$ ^u ! surface1 & ! film is suffici5tly s5sitive4 ,!re are ?ree modes ( apply+ solutions1 viz4 by bru%+1 float+1 & imm]sion4 ,! quantity ( solution left on ! pap] v>ies ) ea*1 & consequ5tly ea* requires a diff]5t =mula4 ,imm]sion 9 a /rong salt+ ,ba? t5ds to give a co>se picture want+ 9 def9ition2 :]eas ! plan ( bru%+ a weak salt+ solution1 produces a pap] defici5t 9 s5sitiv5ess1 & yield+ a pale r$ image )\t prop] dep? ( %ad[4 ,b indep5d5t ( ^! diff]5ces1 ! *emical nature ( ! size employ$ also influ5ces ! ton+ ( ! ,pr9t4 ,= in/ance1 9 ! process above giv51 if ! ,positives1 aft] hav+ be5 fully ton$ 9 ! ,gold ,ba?1 & wa%$ 9 cold wat]1 be treat$ ) boil+ wat]1 ! t9t imm$iately *anges to a dull r$2 b on blott+ (f betwe5 %eets ( bibul\s pap] & press+ ) a hot iron1 ! d>k tones are re/or$4 ,?is de/ruction ( ! t9t by boil+ wat]1 & its re/oration by dry heat1 is due 9 great "p to ! animal sub/ance employ$ 9 siz+ ! pap]2 & x w be f\nd t pr9ts ^u a =eign pap]1 su* z ! ,saxony ,positive1 salt$ ) a t5-gra9 solution & s5sitiz$ ) ,ammonio-,nitrate1 d n lose _! tones 9 hot wat] & are n mu* d>k5$ by iron+4 ,! peculi>ity ( ! siz+ ( ! ,engli% ,photographic pap]s mu/ !re=e be borne 9 m9d1 & all[ance made = ! additional s5sitiv5ess & alt]ation ( col\r :i* x produces4 ,:5 a =mula is giv51 ! pap] :i* is recomm5d$ = t p>ticul> =mula %\ld alone be us$4 ,,section ,,ii4 ,positive ,pr9t+ by ,developm5t4 ,negative pr9t+ processes w be f\nd useful dur+ ! dull w9t] mon?s1 & at o!r times :5 ! light is feeble1 or :5 x is requir$ to produce a l>ge numb] ( impressions f a ,negative 9 a %ort space ( "t4 ,! plan ( developm5t also enables ! op]ator to obta9 ,positives ( great] /ability ?an ^? yield$ by ! direct action ( light4 ,?ree processes may be describ$1 ! fir/ ( :i* gives ,positives ( an agreeable col\r1 b ! second1 on ,iodide ( ,silv]1 ! greate/ p]man5cy "u unfav\rable conditions4 ,,negative ,,pr9t+ ,,processes ,,^u ,,*loride ,,( ,,silv]4 ,positives may be obta9$ by expos+ pap] prep>$ ) ,*loride ( ,silv] to ! action ( light until a fa9t image is p]ceptible1 & subsequ5tly develop+ by ,gallic ,acid2 b 9 ?is process x is difficult to obta9 suffici5t contra/ ( light & %ade2 ! impression1 if suffici5tly expos$ & n too mu* develop$1 be+ feeble1 ) a want ( int5sity 9 ! d>k p>ts4 ,by associat+ ) ! ,*loride an organic salt ( ,silv]1 su* z ! ,citrate1 ?is difficulty may be ov]come1 & ! %ad[s be br\ght out ) great dep? & di/9ctness4 ,! pap]s are salt$ ) a mix$ ,*loride & ,citrate z 9 ! =mula = ! ,ammonio-,nitrate ,process4#di ,!y are !n r5d]$ s5sitive ^u a ,ba? ( ,nitrate ( ,silv] conta9+ ei!r ,citric or ,acetic ,acid1 :i* are us$ 9 ,negative processes to pres]ve ! cle>ness ( ! :ite p>ts "u ! influ5ce ( ! develop]4 #di ,! =mula at p4 #bdf may be modifi$ ) advantage3 use d\ble ! quantity ( ,gelat9e1 & half ! am\nt ( ,citrate & ,*loride4 ,! ,ba? ( ,aceto-,nitrate is prep>$ z foll[s3-- ,nitrate ( ,silv] #cj gra9s4 ,glacial ,acetic ,acid #cj m9ims4 ,wat] #a fluid ounce4 ,float ! pap]s 7,papi] ,saxe or ,papi] ,rive7 ^u ! ,ba? = ?ree m9utes1 & susp5d !m to dry 9 a room f :i* act9ic rays are p]fectly exclud$4 ,! exposure to light1--:i* is conduct$ 9 ! ord9>y pr9t+ frame1 ! ,negative & s5sitive pap] be+ laid 9 contact 9 ! usual way1--w seldom be long] ?an ?ree or f\r m9utes1 ev5 ^u a dull day4 ,x may be regulat$ by ! col\r assum$ by ! project+ m>g9 ( ! pap]2 b x is q possible to tell by ! appe>ance ( ! image :5 x has receiv$ a suffici5t am\nt ( exposure3--! :ole ( ! picture %\ld be se51 except+ ! lighte/ %ades1 & x w be f\nd t v few details c be br\ght out 9 ! developm5t :i* 7 altoge!r invisible be=e ! ,gallic ,acid 0 appli$4 ,! develop+ solution is prep>$ z foll[s3-- ,gallic ,acid #b gra9s4 ,wat] #a fluid ounce4 ,9 v cold wea!r x may be necess>y to employ a saturat$ solution ( ,gallic ,acid1 conta9+ ab\t f\r gra9s to ! ounce2 :]eas 9 w>m wea!r ! image w develope too quickly1 & ,acetic ,acid mu/ be add$ 7see ! rem>ks at ! end ( ! process1 p4 #bff74 ,to facilitate ! solution ( ! ,gallic ,acid1 /& ! bottle 9 a w>m place ne> ! fire4 ,a lump ( ,camphor float$ 9 ! liquid1 or a drop ( ,oil ( ,cloves add$1 w to a great ext5t prev5t x f becom+ m\ldy by keep+2 b if once m\ld has =m$1 ! bottle mu/ be well cleans$ ) ,nitric ,acid1 or ! decomposition ( ! fre% ,gallic ,acid w be ha/5$4 ,p\r ! solution ( ,gallic ,acid into a flat di%1 & imm]se ! ,pr9ts two or ?ree at a "t1 mov+ !m ab\t1 & us+ a glass rod to remove air-bubbles4 ,! developm5t is rapid1 & w be complet$ 9 ?ree or f\r m9utes4 ,if ! ,pr9t developes sl[ly1 becomes v d>k 9 col\r by cont9u+ ! action ( ! ,gallic ,acid1 b %[s no half-tones1 x has n be5 expos$ suffici5tly long to ! light4 ,an ov]-expos$ pro(1 on ! o!r h&1 developes ) unusual rapidity1 & x is necess>y to remove x spe$ily f ! ,ba? 9 ord] to pres]ve ! cle>ness ( ! :ite p>ts2 :5 tak5 out to ! light1 x appe>s pale & r$1 ) no dep? ( %ad[4 ,! ext5t to :i* ! developm5t %\ld be c>ri$ dep5ds ^u ! k9d ( ,pr9t desir$4 ,by pu%+ ! action ( ! ,gallic ,acid1 a d>k picture n mu* alt]$ by ! fix+ ,ba? w be produc$4 ,b a bett] result z reg>ds col\r & gradation ( tone w be obta9$ by remov+ ! ,pr9t f ! develop+ solution :il/ 9 ! light r$ /age1 & ton+ x subsequ5tly by means ( ,gold2 9 :i* case x w correspond bo? 9 appe>ance & prop]ties to a ,positive obta9$ by ! direct action ( light 7see ! rem>ks at page #afg74 ,:5 x is int5d$ to foll[ ! latt] plan1 ! action ( ! develop] mu/ be /opp$ at a po9t :5 ! pro( appe>s light] ?an x is to rema92 s9ce ! ,sel d'or ,ba? adds a little to ! int5sity1 & ! image becomes some:at m vigor\s on dry+4 ,wa% ! ,pr9ts 9 cold wat] 9 ord] to extract all ! ,gallic ,acid4 ,!n tone ) ,sel d'or 9 ! mann] describ$ 9 ! next ,section1 & fix 9 ! usual way4 ,! :ites w ) c>e be kept pure2 or ) only a fa9t yell[ t+e1 :i* is n objectionable4 ,^u comp>+ ! develop$ ,pr9ts ) o!rs obta9$ by ! direct action ( light ^u ! same s5sitive pap]1 x is evid5t t ! advantage is slightly on ! side ( ! latt]2 b ! diff]5ce is s small t x w\ld be ov]look$ 9 pr9t+ l>ge subjects1 = :i* ! ,negative ,process is m especially adapt$4 ,! col\r ( bo? k9ds ( ,positives is ! same1 or p]haps a %ade d>k] 9 ! develop$ pro(s1 :i* are usually ( a violet-purple tone1 b sometimes ( a d>k *ocolate-br[n4 ,a develop+ process ) ,s]um ( ,milk4--,! use ( :ey z a vehicle = ,*loride ( ,silv] has some?+ ! same effect z t produc$ by add+ a ,citrate4 ,?is may be trac$ to ! pres5ce ( ! ,milk ,sug> & ( a portion ( uncoagulat$ ,case9e left 9 ! ,s]um4 ,! only difficulty 9 ! process is to coagulate ! milk 9 su* a way z to sep>ate ! great] "p b n ! :ole ( ! ,case9e4 ,milk :i* has become s\r1 or to :i* an acid has be5 add$1 is n consid]$ s good = ! purpose z t :i* has be5 treat$ ) r5net2 & ev5 :5 r5net is us$ x mu/ be ( ! be/ quality or its action w be imp]fect4 ,! s]um mu/ filt] cle> ?r\gh1 blott+-pap]2 b x %\ld n run v rapidly1 or 9 all probability ! :ole ( ! ,case9e has be5 sep>at$1 & ! fluid conta9s little besides sug>4 ,! :ey :i* is left aft] *eese-mak+1 commonly answ]s ! purpose1 if cl>ifi$ by beat+ x up ) ! :ite ( an egg & subsequ5tly boil+ & filt]+4 ,globules ( oil mu/ be sep>at$ z f> z possible1 or !y w produce a greas9ess ( ! pap]4#ej #ej ,see ! ,vocabul>y1 ,"p ,,iii11 ,art4 ,milk1 = fur!r p>ticul>s4 ,salt ! prep>$ ,s]um ) ,*loride ( ,sodium or ,ammonium2 9 quantity ab\t eight or t5 gra9s to ea* fluid ounce1 & r5d] s5sitive ^u ! same ,ba? z t recomm5d$ = ! ,citrate ,process4 ,a ,,negative ,,pr9t+ ,,process ,,^u ,,iodide ,,( ,,silv]4 ,iodide ( ,silv] is m s5sitive to ! reception ( ! invisible image ?an ! o!r comp\nds ( t metal2 & h5ce x is usefully employ$ 9 pr9t+ enl>g$ ,positives f small ,negatives1 by means ( ! ,cam]a4 ,! great /ability ( ! pro(s ^u ,iodide ( ,silv] w also be a recomm5dation ( ?is process :5 unusual p]man5cy is requir$4 ,take ( ,iodide ( ,potassium #afj gra9s4 ,wat] #bj fluid ounces4 ,! be/ pap] to use w be ei!r ,turn]'s ,calotype1 or ,:atman's or ,holl+wor?'s ,negative2 ! =eign pap]s d n succe$ ) ! above =mula 7p4 #beh74 ,float ! pap] on ! iodiz+ ,ba? until x ceases to curl up & lies flat ^u ! liquid3 !n p9 up to dry 9 ! usual way4 ,r5d] s5sitive ^u a ,ba? ( ,aceto-,nitrate ( ,silv] conta9+ #cj gra9s ( ,nitrate ( ,silv] ) #cj m9ims ( ,glacial ,acetic ,acid to ea* ounce ( wat]4 ,:5 ! %eet is q dry1 place x 9 contact ) ! ,negative 9 a pressure frame1 & expose to a feeble light4 ,ab\t #cj seconds w be an av]age "t ^u a dull w9t]'s day1 on :i* x w\ld be impossible to pr9t at all 9 ! ord9>y way4 ,on remov+ ! ,negative no?+ :atev] is se5 ^u ! pap]1 ! image be+ /rictly invisible 9 ?is process unless ! exposure has be5 c>ri$ too f>4 ,develope by imm]sion 9 a saturat$ solution ( ,gallic ,acid1 prep>$ 9 ! mann] describ$ at page #bfa4 ,! image appe>s sl[ly1 & ! process may la/ f #ae m9utes to half an h\r4 ,if ! exposure has be5 correctly tim$1 ! ,gallic ,acid appe>s at l5g? almo/ to cease act+2 b :5 ! pro( has be5 ov]-expos$1 ! developm5t goes on un9t]rupt$ly1 & ! image becomes too d>k1 p>tak+ m ( ! "* ( a ,negative ?an a ,positive4 ,! usual rule1 t "u-expos$ pro(s develope sl[ly b %[ no half-tones1 & t ! ov]-expos$ develope ) unusual rapidity1 is also obs]v$ 9 ! process ) ,iodide ( ,silv]4 ,aft] ! picture is fully br\ght out1 wa% 9 cold1 & subsequ5tly 9 w>m wat]1 to remove ! ,gallic ,acid1 :i*1 if all[$ to rema91 w\ld discol\r ! ,hyposulphite ,ba?4 ,!n fix ! ,pr9t 9 a solution ( ,hyposulphite ( ,soda1 "o "p to two ( wat]1 cont9u+ ! action until ! yell[ col\r ( ! ,iodide disappe>s4 ,! fix+ ,ba? ought n to produce mu* *ange 9 ! t9t4 ,if ! ,positive loses its d>k col\r on imm]sion 9 ! ,hyposulphite1 & becomes pale & r$1 x has be5 insuffici5tly develop$4 ,! !ory ( ?is "p ( ! process %\ld be und]/ood3--,x is p>ticul>ly ! second /age ( ! developm5t ( a ,photograph 7see p4 #add7 on :i* ! fix+ ,ba? produces no effect2 & !re=e a consid]able *ange ( col\r 9 ! ,hyposulphite indicates t too little ,silv] has be5 deposit$1 & ! rem$y w be to pu% ! developm5t1 add+ a little ,aceto-,nitrate to ! ,gallic ,acid if ! /r5g? ( ! ,ba? be f\nd insuffici5t to yield d>k tones4 ,! col\r ( ,positives develop$ ^u ,iodide ( ,silv] is n agreeable1 & !y become blue & inky :5 ton$ ) gold4 ,by fix+ ! pro( 9 ,hyposulphite ( ,soda :i* has be5 long us$ & has acquir$ sulphurett+ prop]ties1 ! t9t is mu* improv$2 b ! p]man5cy ( ! ,pr9t "u unfav\rable conditions is less5$ by adopt+ t mode ( ton+4 ,a ,,negative ,,pr9t+ ,,process ,,^u ,,bromide ,,( ,,silv]4 ,by sub/itut+ ! ,bromide = ! ,iodide ( ,silv] 9 ! above process1 ! proportions & details ( manipulation be+ 9 o!r respects ! same1 a m agreeable col\r is obta9$4 ,pap] prep>$ ) ,bromide ( ,silv] is less s5sitive ?an ! ,iodide1 b an exposure ( "o m9ute 79 ! pr9t+ frame7 w usually be suffici5t ev5 on a dull day4 ,! image is ne>ly lat5t1 b sometimes a v fa9t outl9e ( ! d>ke/ %ad[s c be se54 ,! proportion ( ,bromide us$ is likely to influ5ce ?is po9t2 ! s5sitiv5ess be+ dim9i%$1 b ! image %[+ m ( ! details be=e developm5t1 :5 ! quantity ( ! ,silv] ,salt is r$uc$ to a m9imum4 ,ei!r ,engli% or ,fr5* pap]s may be us$1 b 9 ! latt] case ! ,bromide %\ld be dissolv$ 9 ,s]um ( ,milk 7p4 #bfb71 or x w be difficult to obta9 a good surface picture4 ,! proportion ( ,bromide may be five gra9s to ! ounce ( ,s]um4 ,^! pro(s1 ev5 :5 simply fix$ 9 pla9 ,hyposulphite ( ,soda1 are sup]ior 9 col\r to ! ,positives pr9t$ by ! la/ =mula ^u ,iodide ( ,silv]2 & ! p]man5cy is v great if ! developm5t be suffici5tly pu%$4 ,! use ( ! ,s]um ( ,milk gives an advantage 9 resi/+ ! oxidiz+ influ5ces to :i* ,positives are liable to be expos$ 7p4 #aej74 ,,g5]al ,,rem>ks ,,on ,,negative ,,pr9t+4 ,pr9t+ by developm5t %\ld n be attempt$ until ! manipulation ( ! ord9>y process by direct exposure to light has be5 acquir$4 ,p]fect cleanl9ess is ess5tial4 ,! salt+ or iodiz+ solution & ! ,aceto-,nitrate ,ba? mu/ be filt]$ cle>1 z ! effect ( small susp5d$ p>ticles 9 produc+ spots is m se5 :5 ! image is br\ght out by a develop]4 ,x w be necess>y to be f> m c>eful 9 exclud+ :ite light ?an 9 ! ord9>y process2 & :5 ,iodide ( ,silv] is us$1 all ! precautions requir$ 9 ! case ( ,collodion ,negatives mu/ be tak54 ,obs]ve p>ticul>ly t ! di%es are kept clean1 or ! ,gallo-,nitrate ( ,silv] w be rapidly discol\r$ 7read ! rem>ks at page #agi74 ,/]eoscopic ,negatives & small portraits are n successfully pr9t$ by developm5t2 s9ce x is difficult to obta9 ! mo/ elaborate def9ition1 & !re is a slight t5d5cy to yell[ness 9 ! :ite p>ts4 ,positives may be develop$ ^u ,album5 pap]1 b ! ,gallic ,acid is apt to discol\r ! lights4 ,9 pr9t+ by developm5t ^u ,*loride ( ,silv]1 ! !ory ( ! subject mu/ be p>ticul>ly /udi$4 ,:5 ! wea!r is cold & ! light bad1 ! developm5t ( ! image proce$s sl[ly1 ! ,gallic ,acid ,ba? rema9s cle>1 & good half-tones are obta9$2 b "u opposite conditions1 ! develop] may become turbid & ! %ad[s be lo/ by excessive deposit ( ,silv]4 ,?is ov]-developm5t w be rem$i$ by pr9t+ ! ,negative 9 a m feeble light 7ne> to ! op5 w9d[ ( a room71 & by add+ ,acetic ,acid to ! develop]1 ab\t #e or #aj m9ims to ! ounce1 s z to br+ out ! image m sl[ly4 ,! int5sity ( action is ?us less5$1 & if ! picture be n "u-expos$1 ! half-tones w be good4 ,obs]ve also :5 prep>+ pap]s ) ,citrate1 t if too mu* ,c>bonate ( ,soda be add$ 9 neutraliz+ ! ,citric ,acid1 ,c>bonate ( ,silv] w be deposit$ 9 ! pap]1 ! effect ( :i* is to remove by degrees ! acidity ( ! ,nitrate ,ba?1 & to produce ov]-developm5t & excessive s5sibility to light4 ,! col\r ( ! pro(s :5 tak5 f ! ,gallic ,acid %\ld be light r$2 ! gradation ( tone n be+ usually s p]fect :5 ! developm5t is c>ri$ into ! second or black /age4 ,x is n recomm5d$ to prep>e too l>ge a /ock ( ! salt$ pap]s1 z !y w probably be liable to m\ld9ess & decomposition unless kept p]fectly dry4 ,,section ,,iii4 ,! ,sel d'or ,process = ton+ ,positives4 ,?is process is some:at m tr\blesome ?an ! plan ( fix+ & ton+ 9 "o solution1 b possesses advantages :i* w pres5tly be enum]at$4 ,! description may be divid$ into ! prep>ation ( ! ton+ ,ba?1 & ! manipulatory details4 ,,! ,,prep>ation ,,( ,,! ,,ton+ ,,ba?4 ,take ( ,*loride ( ,gold #a gra94 ,pure ,hyposulphite ( ,soda #c gra9s4 ,hydro*loric ,acid #d m9ims4 ,wat]1 di/ill$ or common #d fluid ounces4 ,dissolve ! ,gold & ,hyposulphite ( ,soda ea* 9 two ounces ( ! wat]2 !n mix quickly by p\r+ ! =m] solution into ! latt]1 & add ! ,hydro*loric ,acid4 ,if ! ,*loride ( ,gold be neutral1 ! liquid w h a r$ t+e1 b if acid1 !n ! solution may be col\rless4 ,! comm]cial ,*loride ( ,gold1 conta9+ usually mu* free ,hydro*loric ,acid1 w n require any addition ( t sub/ance4 7,see ! ,vocabul>y1 ,"p ,,iii47 ,9 place ( mak+ an extemporane\s ,hyposulphite ( ,gold by mix+ ! ,*loride ) ,hyposulphite ( ,soda1 ! ,cry/alliz$ ,sel d'or may be us$1 add+ ab\t half a gra9 to ! ounce ( wat]1 acidifi$ z be=e2 b ! objection to ! employm5t ( ?is salt is its exp5se1 & also ! difficulty ( obta9+ x 9 a pure =m2 "s samples conta9+ less ?an five p] c5t1 ( ,gold4 ,x w be f\nd v conv5i5t to keep ! two solutions on h& ready = mix+1 viz4 ! ,*loride ( ,gold dissolv$ 9 wat] 9 ! proportion ( a gra9 to ! dra*m1 & ! ,hyposulphite ( ,soda1 ?ree gra9s to ! dra*m4 ,:5 requir$ = use1 measure out a fluid dra*m ( ea*1 dilute ) wat] to two ounces1 & mix4 ,x is possible t ! ?ree-gra9 solution ( ,hyposulphite ( ,soda may by long keep+ become decompos$1 ) precipitation ( ,sulphur4 ,! effect ( ?is w\ld be to produce a turbidity & deposit ( ,gold on mix+ ! +r$i5ts = ! ,ba?1 ! ,*loride ( ,gold be+ 9 excess ov] ! ,hyposulphite ( ,soda 7see p4 #bej74 ,! ,ba? ( ,sel d'or is always mo/ active :5 rec5tly mix$1 b x w keep good = "s days if contact ) free ,nitrate ( ,silv] be avoid$4 ,! addition ( ?is sub/ance produces a r$ deposit 9 ! ,ba?1 conta9+ ,gold1 & ! solution !n becomes useless4 ,,details ,,( ,,manipulation4 ,! pap] may be prep>$ by ei!r ( ! =mul giv5 9 ! fir/ ,section ( ?is ,*apt]1 accord+ to ! t9t desir$4 ,! pure black tones are obta9$ mo/ easily ) ! ,ammonio-,nitrate pap]1 & ! purple t9ts1 )\t gloss1 on pap] prep>$ ) pla9 ,*loride & ,citrate ( ,soda4 ,! pr9t+ is n c>ri$ q to ! usual int5sity1 z ! half-tones are v little dissolv$ 9 ?is process4 ,on be+ tak5 f ! frame1 ! pr9ts are wa%$ ?or\ghly 9 common wat] until x ceases to become milky2 t is1 until ! great] "p ( ! ,nitrate ( ,silv] has be5 remov$4 ,! wa%+ mu/ be conduct$ 9 a d>k place1 b x is n necess>y to ha/5 x2 ! pro(s may be ?r[n into a pan ( wat] cov]$ ) a clo?1 & all[$ to rema9 until requir$ = t9t+4 ,a trace ( free ,nitrate ( ,silv] usually escapes ! wa%+2 ?is w\ld cause a yell[ deposit on ! ,pr9t1 & also 9 ! ton+ ,ba?4 ,x mu/ !re=e be remov$1 ei!r by add+ a little common salt to ! wat] dur+ ! la/ wa%+s1 or by means ( a dilute solution ( ,ammonia4 ,= pla9 pap] ,pr9ts ! =m] plan w be f\nd ! lea/ tr\blesome2 b ) ,album5 pro(s#ea ! ,ammonia is requir$1 9 ord] to dissolve away a portion ( ! ,album9ate ( ,silv] :i* has escap$ ! action ( light1 be=e submitt+ ! pr9t to ! gold2 o!rwise ! d>k tones w\ld ne>ly disappe> 9 ! fix+ ,ba?1 ! ,hyposulphite c>ry+ away ! ,gold ) ?is sup]ficial lay] ( silv] salt4 #ea ,! amateur is recomm5d$ n to use ,album9iz$ pap] 9 ?is process until he has become accu/om$ to ! manipulations2 ! pla9 pap] pr9ts be+ ton$ ) m ease & c]ta9ty4 ,to prep>e ! ,ammonia ,ba?1 take ( ,liquor ,ammoni #a dra*m4 ,common ,wat] #a p9t4 ,! exact quantity is n mat]ial2 if ! liquid smells fa9tly ( ,ammonia1 x w be suffici5t4 ,place ! wa%$ ,pr9ts 9 ?is ,ba?1 two or ?ree at a "t1 & all[ !m to rema9 until ! purple t9t gives place to a r$ tone4 ,! action mu/ be wat*$1 because if ! ,ammonia ,ba? be /rong1 ! pro( becomes unusually pale & r$1 & :5 ?is is ! case a little brilliancy is lo/ 9 ! aft]-t9t+4 ,z ! ,pr9t is comp>atively ins5sitive to light :5 ! excess ( ,nitrate has be5 wa%$ away1 x is n necess>y to d>k5 ! room2 b a bright light proce$+ f an op5 door or w9d[ %\ld be avoid$4 ,aft] us+ ! salt or ! ,ammonia1 soak ! ,pr9ts aga9 = a m9ute or s 9 common wat]4 ,!n place !m 9 ! ton+ ,ba? ( ,gold & acid2 d n put 9 too _m at once1 & move !m ab\t occasionally1 to prev5t spots ( imp]fect action at ! po9t :]e ! %eets t\* ea* o!r4 ,! =eign pap]s1 pla9 salt$1 col\r rapidly 9 two or ?ree m9utes4 ,engli% pap]s require five to t5 m9utes2 ,album9iz$1 t5 m9utes to a qu>t] ( an h\r4 ,! t5d5cy ( ! ,gold ,ba? is to give a blue tone to ! image2 h5ce pro(s :i* are light r$ aft] us+ ! salt or ,ammonia1 become1 fir/ r$-purple1 & !n violet-purple 9 ! ,sel d'or4 ,album5 ,pr9ts assume "s %ade ( br[n1 or ( purple if n too /rongly ,album9iz$4 ,ammonio-,nitrate pap]s highly salt$1 & prep>$ )\t ,citrate1 become fir/ d>k purple1 & !n blue & inky2 ! ,citrate is int5d$ to obviate ?is inky t9t4 ,:5 ! d>ke/ tones are rea*$1 ! ,ba? produces no fur!r effect1 b ev5tually 7m especially if ! solution be n %ield$ f light 87 !re is a little decomposition1 produc+ a cream-col\r$ deposit ^u ! lights4 ,! ton+ be+ complet$1 ! ,pr9ts are aga9 wa%$ = an in/ant 9 wat]1 to remove ! excess ( gold solution4 ,?is wa%+ mu/ n be cont9u$ long] ?an two or ?ree m9utes1 or !re w be dang] ( yell[ness ( ! :ites2 ?is h[ev] ought n to happ5 ) prop] precautions4 ,la/ly1 ! pro(s are fix$ 9 a solution ( ,hyposulphite ( ,soda1 "o "p to f\r ( wat]2 :i* may be us$ _m times successively4 ,?is ,ba? alt]s ! tone v little if ! deposit ( ,gold be well fix$ on ! ,pr9t2 b ! writ] has (t5 obs]v$ 9 ! case ( ,album5 pap] & pap] prep>$ ) ,citrate 7,=mula ,,ii47 t if remov$ too quickly f ! ,sel d'or1 ! purple tones *ange by imm]sion 9 ! ,hyposulphite to a *ocolate-br[n4 ,ammonio-,nitrate ,pr9ts are less liable to alt] 9 ?is way4 ,9 ord] t ! fix+ may be prop]ly p]=m$1 ! "t ( imm]sion %\ld n be less ?an t5 m9utes ) a por\s pap]1 pla9 salt$2 or fifte5 m9utes 9 ! case ( an ,engli% or album9iz$ pap]4 ,ammonia may be us$ = fix+ pla9 pap] ,pr9ts2 ab\t "o "p ( ! ,liquor ,ammoni1 to f\r ( wat]4 ,t5 m9utes' imm]sion w usually be suffici5t1 & ! tone is v little affect$4 ,?is process is a good "o1 b ! pung5t smell ( ! ,ammonia is an objection1 & ! ,ba? discol\rs by use4 ,"s c>e too is requir$ 9 ord] to ensure a prop] fix+ ( ! pr9ts 7see ! rem>ks at page #aca74 ,= directions to wa% & m\nt ! pro(s1 see page #bee4 ,x w sometimes happ5 9 ! ,sel d'or process1 f ! ton+ ,ba? hav+ b little solv5t action on ! light %ades1 t ! ,pr9ts1 aft] be+ wa%$ & dri$1 appe> too d>k2 ?is may be rem$i$ by lay+ !m = a few m9utes 9 a v dilute solution ( ,*loride ( ,gold 7five or six drops ( ! yell[ solution ( ! ,*loride to a few ounces ( wat]7 & wa%+ = an additional qu>t] ( an h\r4 ,or an ov]-pr9t$ ,positive may be sav$ by ton+ x ) ,*loride ( ,gold in/ead ( ,sel d'or4 ,9 t case1 aft] prop] removal ( ! free ,nitrate ( ,silv]1 a few drops ( a lemon-yell[ solution ( ,*loride ( ,gold 7) a fragm5t ( ,c>bonate ( ,soda add$ to remove acidity1 p4 #acb71 %\ld be p\r$ ov] ! ,pr9t1 :i* is to be subsequ5tly fix$ 9 ! usual way4 ,advantages ( ton+ by ,sel d'or4--,?is process w be f\nd especially useful by ^? :o pr9t l>ge ,positives4 ,! solutions may be mix$ 9 a few m9utes1 &1 be+ v dilute1 are economical4 ,x is n ev5 necess>y to employ a ,ba? = ton+1 b if ! ,sel d'or solution be prep>$ ( ab\t twice or ?ree times ! /r5g? giv5 9 ! =mula1 x w be suffici5t to p\r a few dra*ms ^u ! surface ( ! pr9t4 ,z ! ,gold solution is always us$ soon aft] mix+1 a uni=m & p]man5t t9t c be obta9$2 :]eas ! s+le fix+ & ton+ ,ba? ( ,gold & ,hyposulphite loses mu* ( its efficacy by keep+1 & ov]-pr9t+ ( ! pro( is requir$ 9 proportion z ! ,ba? becomes old]4 ,,section ,,iv4 ,on a mode ( ,pr9t+ enl>g$ & r$uc$ ,positives1 ,transp>5cies1 etc41 f ,collodion ,negatives4 ,to expla9 ! mann] 9 :i* a ,photograph may be enl>g$ or r$uc$ 9 ! process ( pr9t+1 x w be necess>y to ref] to ! rem>ks made at page #eb1 on ! conjugate foci ( l5ses4 ,if a ,collodion ,negative be plac$ at a c]ta9 di/ance 9 front ( a ,cam]a1 & 7by us+ a tube ( black clo?7 ! light be admitt$ into ! d>k *amb] only ?r\gh ! ,negative1 a r$uc$ image w be =m$ ^u ! gr\nd glass2 b if ! ,negative be advanc$ ne>]1 ! image w increase 9 size1 until x becomes fir/ equal to1 & !n l>g] ?an1 ! orig9al ,negative2 ! focus becom+ m & m di/ant f ! l5s1 or rec$+1 z ! ,negative is br\ght ne>]4 ,aga91 if a ,negative portrait be plac$ 9 ! ,cam]a slide1 & ! in/rum5t be+ c>ri$ into a d>k room1 a hole be cut 9 ! w9d[-%utt] s z to admit light ?r\gh ! ,negative1 ! lum9\s rays1 aft] refraction by ! l5s1 w =m an image ( ! exact size ( life ^u a :ite scre5 plac$ 9 ! position orig9ally occupi$ by ! sitt]4 ,^! two planes1 9 fact1 t ( ! object & ( ! image1 are /rictly conjugate foci1 &1 z reg>ds ! result1 x is immat]ial f :i* ( ! two1 ant]ior or po/]ior1 ! rays ( light proce$4 ,!re=e 9 ord] to obta9 a r$uc$ or enl>g$ copy ( a ,negative1 x is necess>y only to =m an image ( ! size requir$1 & to project ! image ^u a s5sitive surface ei!r ( ,collodion or pap]4 ,a good arrangem5t = ?is purpose may be made by tak+ an ord9>y ,portrait ,cam]a1 & prolong+ x 9 front by a deal box black5$ inside & ) a d\ble body1 to' admit ( be+ l5g!n$ out z requir$2 or1 m simply1 by add+ a framework ( wood cov]$ 9 ) black clo?4 ,a groove 9 front c>ries ! ,negative1 or receives ! slide conta9+ ! s5sitive lay]1 z ! case may be4 ,9 r$uc+ ,photographs1 ! ,negative is plac$ 9 front ( ! l5s1 9 ! position ord9>ily occupi$ by ! object2 b 9 mak+ an enl>g$ copy1 x mu/ be fix$ beh9d ! l5s1 or1 :i* is equival5t1 ! l5s mu/ be turn$ r\nd1 s t ! rays ( light transmitt$ by ! ,negative ent] ! back glass ( ! comb9ation1 & pass out at ! front4 ,?is po9t %\ld be att5d$ to 9 ord] to avoid indi/9ctness ( image f sph]ical ab]ration4 ,a ,portrait comb9ation ( l5ses ( #b-a_/b or #c-a_/d in*es diamet] is ! be/ =m to use1 & ! act9ic & lum9\s foci %\ld accurately correspond1 z any diff]5ce betwe5 !m w\ld be increas$ by enl>g+4 ,a /op ( an in* or an in* & a half ap]ture plac$ betwe5 ! l5ses obviates to "s ext5t ! loss ( %>p outl9e usually foll[+ enl>gem5t ( ! image4 ,! light may be admitt$ ?r\gh ! ,negative by po9t+ ! ,cam]a t[>ds ! sky2 or direct sunlight may be us$1 ?r[n ^u ! ,negative by a plane reflector4 ,a common sw+ look+-glass1 if cle> & free f specks1 does v well2 x %\ld be s plac$ t ! c5tre on :i* x turns is on a level ) ! axis ( ! l5s4 ,! be/ ,negatives = pr9t+ enl>g$ ,positives are ^? :i* are di/9ct & cle>2 & x is important to use a small ,negative1 :i* /ra9s ! l5s less & gives a bett] result ?an "o ( l>g] size4 ,9 pr9t+ by a #b-a_/d l5s = in/ance1 prep>e ! ,negative ^u a plate ab\t two in*es squ>e1 & aft]w>ds enl>ge x f\r diamet]s4 ,pap] conta9+ ,*loride ( ,silv] is n suffici5tly s5sitive to receive ! image1 & ! ,pr9t %\ld be =m$ ^u ,collodion1 or on iodiz$ pap] develop$ by ,gallic ,acid 7see p4 #bfc74 ,! exposure requir$ w v>y n only ) ! int5sity ( ! light & ! s5sibility ( ! surface us$1 b also ) ! degree ( r$uction or enl>gem5t ( ! image4 ,9 pr9t+ ^u ,collodion ! result+ picture is ,positive by transmitt$ light2 x %\ld be back$ up ) :ite v>ni%1 & !n becomes ,positive by reflect$ light4 ,! tone ( ! blacks is improv$ by treat+ ! plate fir/ ) ,bi*loride ( ,m]cury1 & !n ) ,ammonia1 9 ! mann] describ$ at pages #aac & #bjg4 ,mr4 ,w5ham1 :o has writt5 a pap] on ! mode ( obta9+ ,positives ( ! life size1 op]ates 9 ! foll[+ way3--he places ! ,cam]a1 ) ! slide conta9+ ! ,negative1 9 a d>k room1 & reflects ! sunlight 9 ?r\gh a hole 9 ! %utt]1 s z to pass fir/ ?r\gh ! ,negative & !n ?r\gh ! l5s2 ! image is receiv$ ^u iodiz$ pap]1 & develop$ by ,gallic ,acid1 9 ! mode describ$ 9 ! second ,section ( ?is ,*apt] 7p4 #bfc74 ,on pr9t+ ,collodion transp>5cies = ! ,/]eoscope4--,?is may be done by us+ ! ,cam]a to =m an image ( ! ,negative 9 ! mode describ$ 9 ! la/ page2 b m simply by ! foll[+ process3--,coat ! glass1 ^u :i* ! ,pr9t is to be =m$1 ) ,collodio-,iodide ( ,silv] 9 ! usual way2 !n lay x ^u a piece ( black clo?1 ,collodion side upp]mo/1 & place two /rips ( pap] ( ab\t ! ?ickness ( c>dbo>d & "o-f\r? ( an in* broad1 along ! two opposite edges1 to prev5t ! ,negative be+ soil$ by contact ) ! film4 ,bo? glasses mu/ be p]fectly flat1 & ev5 !n x may happ5 t ! ,negative is unavoidably wett$2 if s1 wa% x imm$iately ) wat]1 & if x be prop]ly v>ni%$1 no h>m w result4 ,a little +5uity w sugge/ a simple framework ( wood1 on :i* ! ,negative & s5sitive plate are reta9$1 sep>at$ only by ! ?ickness ( a %eet ( pap]2 & ! use ( ?is w be bett] ?an hold+ ! comb9ation 9 ! h&4 ,! pr9t+ is conduct$ by ! light ( gas1 or ( a camph9e or mod]ator lamp2 diffus$ daylight w\ld be too p[]ful4 ,! employm5t ( a concave reflector1 :i* may be pur*as$ = a few %ill+s1 ensures p>allelism ( rays1 & is a great improvem5t4 ,! lamp is plac$ 9 ! focus ( ! mirror1 :i* may at once be asc]ta9$ by mov+ x backw>ds & =w>ds until an ev5ly illum9at$ circle is ?r[n ^u a :ite scre5 held 9 front4 ,?is 9 fact is "o ( ! disadvantages ( pr9t+ by a nak$ flame--t ! light falls mo/ p[]fully ^u ! c5tral "p1 & less s ^u ! edges1 ( ! ,negative4 ,! picture mu/ be expos$ = a long] or %ort] "t 7ab\t t5 seconds w be an av]age7 accord+ to its behavi\r dur+ developm5t 7see p1 #bbd72 ?is process1 z well z ! fix+1 is conduct$ 9 ! same mann] z = ,collodion pictures g5]ally4 ,"s adopt ! plan ( :it5+ by ,corrosive ,sublimate1 & aga9 black5+ by dilute ,ammonia1 z an improvem5t to ! col\r ( ! d>k %ad[s 7see p4 #aac74 ,if ?is mode ( pr9t+ ^u ,collodion be conduct$ ) c>e1 ! ,negative be+ sep>at$ f ! film by ! smalle/ int]val only1 ! loss ( di/9ctness 9 outl9e w sc>cely be p]ceiv$4 ,/]eoscopic transp>5cies may also be pr9t$ by ! dry ,collodion process describ$ 9 ,*apt] ,,vi41 or by ! ,collodio-,album5 process4 ,mr4 ,llewellyn recomm5ds ! employm5t ( a solution ( ,oxymel1 s dilute t ! plate becomes ne>ly dry1 & may be laid 9 contact ) ! ,negative )\t fe> ( injury 7see ! footnote at page #cjb74 ,,*apt] ,v4 ,,classification ,,( ,,causes ,,( ,,failure ,,9 ,,! ,,collodion ,,process4 ,section ,i4--,imp]fections 9 ,collodion ,photographs4 ,section ,,ii4--,imp]fections 9 ,pap] ,positives4 ,,section ,i4 ,imp]fections 9 ,negative & ,positive ,collodion ,photographs4 ,! foll[+ may be m5tion$3--fogg+--spots-- m>k+s1 etc4 ,,causes ,,( ,,fogg+ ,,( ,,collodion ,,plates4 #a4 ,ov]-exposure ( ! ,plate4--,?is is likely to happ5 :5 us+ ! full ap]ture ( a d\ble comb9ation l5s = di/ant objects brightly illum9at$1 ! ,collodion be+ highly s5sitive4 ,also f ! film be+ v blue & transp>5t1 ) too little ,iodide ( ,silv] 7p4 #aad74 #b4 ,diffus$ ,light4--a4 ,9 ! develop+ room4 ,?is is a frequ5t cause ( fogg+1 & especially s :5 ! common yell[ calico is employ$1 :i* is apt to fade4 ,use a treble ?ickness1 or procure ! wat]pro( mat]ial1 9 :i* ! pores are /opp$ ) gutta-p]*a4--b4 ,9 ! ,cam]a4 ,! slide may n fit accurately1 or ! door does n %ut close4 ,?r[ a black clo? ov] ! ,cam]a dur+ ! exposure ( ! plate4--c4 ,f direct rays ( ! sun or ! light ( ! sky fall+ ^u ! l5s4 ,) ! full ap]ture ( a d\ble comb9ation ,l5s1 a portion ( sky includ$ 9 ! field 7z = in/ance to =m ! backgr\nd ( a portrait7 is apt to cause fogg+4 ,! portrait w probably be m brilliant if a funnel-%ap$ canvas bag1 or a curta9 ) an oblong ap]ture admitt+ only ! rays proce$+ f ! sitt]1 be plac$ 9 front ( ! ,cam]a4 #c4 ,alkal9ity ( ! ,ba?4--,?is condition1 expla9$ at page #hh1 may be due to "o ( ! foll[+ causes3--a4 ,! use ( ,nitrate ( ,silv] :i* has be5 too /rongly fus$ 7p4 #ac74--;b4 ,con/ant employm5t ( a ,collodion conta9+ free ,ammonia or ,c>bonate ( ,ammonia 7p4 #hi74--;c4 ,addition ( ,pota%1 ,ammonia1 or ,c>bonate ( ,soda to ! ,nitrate ,ba?1 9 ord] to remove free ,nitric ,acid 7p4 #hi74--;d4 ,use ( ra9-wat] or h>d wat] = mak+ ! ,nitrate ,ba? 7ra9-wat] usually conta9s traces ( ,ammonia2 h>d wat] (t5 ab\nds ) ,c>bonate ( ,lime74 ,9 ei!r case ! alkal9ity may easily be remov$ by ! addition ( ,acetic ,acid1 "o drop to f\r ounces ( ! solution4 ,! prop] mode ( te/+ = alkal9ity is describ$ at p4 #hi4 #d4 ,decomposition ( ! ,nitrate ,ba?4--a4 ,by con/ant exposure to light 7! injuri\s effects ( ?is w be mo/ly se5 :5 ,positives are tak574--b4 ,by organic matt]3 ?is is sometimes pres5t 9 ,nitrate ( ,silv] :i* has be5 prep>$ f ! residues ( old ,ba?s2 or x may be introduc$ by float+ pap]s = ! pr9t+ process ^u ! ,ba?1 or by dissolv+ ! cry/als ( ,nitrate ( ,silv] 9 putrid ra9-wat]1 or 9 impure di/ill$ wat] collect$ f ! cond5s$ wat] ( /eam-boil]s & contam9at$ ) oily matt]4--c4 ,decomposition ( ! ,ba? by contact ) metallic iron or copp]1 or ) a fix+ ag5t1 or a develop+ ag5t 7p4 #ij74 #e4 ,faults ( ! develop+ solution4--a4 ,br[n & decompos$ solution ( ,pyrogallic ,acid2 ?is may sometimes be us$ ) impunity1 b x t5ds1 z a rule1 to facilitate irregul> r$uction ( ,silv]4--h4 ,impure ,acetic ,acid hav+ a smell ( ,g>lic & :i* probably conta9s ,sulphur 9 organic comb9ation4--c4 ,omission ( ! ,acetic ,acid 9 ! develop]3 ?is w produce a univ]sal blackness4 #f4 ,sundry o!r causes ( fogg+4--a4 ,vap\r ( ,ammonia or ,hydrosulphate ( ,ammonia1 or ! products ( ! combu/ion ( coal-gas1 escap+ into ! develop+ room4--b4 ,developm5t ( ! image by imm]sion 9 solution ( ,sulphate ( ,iron3 ?is is a safe plan :5 ! films are =m$ 9 an acid ,nitrate ,ba?2 b ) pale films =m$ 9 a *emically neutral ,ba? x is bett] to p\r ! fluid ov] ! plate1 & n to use ! same portion twice4--c4 ,r$ipp+ ! plate 9 ! ,ba? be=e developm5t3 ?is is apt to give a foggy picture :5 us+ an old ,ba?1 & is n recomm5d$4 ,sy/ematic plan ( proce$+ to detect ! cause ( ! fogg+4--,if ! amateur has _h b little exp]i5ce 9 ! ,collodion process1 & is us+ ,collodion ( mod]ate s5sitiv5ess & a new ,ba?1 ! probability is t ! fogg+ is caus$ by ov]-exposure4 ,hav+ obviat$ ?is1 proce$ to te/ ! ,ba?2 if x is made f pure mat]ials1 & does n re/ore ! blue col\r ( a piece ( litmus-pap] previ\sly r$d5$ by hold+ x ov] ! m\? ( a glacial ,acetic ,acid bottle1 x may be consid]$ 9 work+ ord]4 ,next prep>e a s5sitive plate1 & aft] dra9+ x = two or ?ree m9utes 9 a d>k place1 p\r on ! develop]3 wa%1 fix1 & br+ out to ! light2 if any mi/9ess is p]ceptible1 ei!r ! develop+ room is n suffici5tly d>k1 or ! ,ba? 0 prep>$ ) a bad sample ( ,nitrate ( ,silv]1 or ) impure ,alcohol1 or impure wat]4 ,on ! o!r h&1 if ! plate rema9s absolutely cle> "u ^! circum/ances1 ! cause ( error may be 9 ! ,cam]a2--!re=e prep>e ano!r s5sitive film1 place x 9 ! ,cam]a1 & proce$ exactly z if tak+ a picture1 ) ! exception ( n remov+ ! brass cap ( ! l5s3 all[ to rema9 = two or ?ree m9utes1 & !n remove & develope z usual4 ,if no indication ( ! cause ( ! fogg+ is obta9$ 9 ei!r ( ^! ways1 !re is e reason to suppose t x is due to diffus$ ,light ga9+ entrance ?r\gh ! l5s4 ,?is cause ( error may (t5 be detect$ by look+ into ! ,cam]a f ! front1 :5 an irregul> reflection w be se5 ^u ! glass4 ,,spots ,,^u ,,collodion ,,plates4 ,spots are ( two k9ds3 spots ( opacity1 :i* appe> black by transmitt$ light1 & :ite by reflect$ light2 & spots ( transp>5cy1 ! rev]se ( ! o!rs1 be+ :ite :5 se5 ^u ,negatives1 & black on ,positives4 ,opaque ,spots are ref]able to an excess ( developm5t at ! po9t :]e ! spot is se52 !y may be caus$ by-- #a4 ,! use ( ,collodion hold+ small p>ticles 9 susp5sion4--,ea* p>ticle becomes a c5tre ( *emical action1 & produces a speck1 or a speck ) a tail to x4 ,! ,collodion %\ld be plac$ aside to settle = sev]al h\rs1 aft] :i* ! upp] portion may be p\r$ (f4 #b4 ,turbidity ( ! ,nitrate solution4--a4 ,f flakes ( ,iodide ( ,silv] hav+ fall5 away into ! solution1 by use ( an ov]-iodiz$ ,collodion4--b4 ,f a deposit =m$ by degrees ^u ! sides ( ! gutta-p]*a tr\gh4--c4 ,f ! inside ( ! tr\gh be+ du/y at ! "t ( p\r+ 9 ! solution4 ,9 ord] to obviate ^! inconv5i5ces1 x is well to make at lea/ half z mu* aga9 ( ! ,nitrate solution z is necess>y1 & to keep x 9 a /ock-bottle1 f :i* ! upp] "p may be p\r$ (f :5 requir$4 ,! frequ5t filtration ( ,silv] ,ba?s is unadvisable1 s9ce ! pap] employ$ may be contam9at$ ) impurities4 #c4 ,du/ ^u ! surface ( ! glass at ! "t ( p\r+ on ! ,collodion4--,p]fectly clean glasses1 if set aside = a few m9utes1 acquire small p>ticles ( du/2 ea* plate %\ld !re=e be g5tly wip$ ) a silk h&k]*ief imm$iately be=e be+ us$4 #d4 ,faults ( ! ,slide4--,sometimes a small hole exi/s1 :i* admits a p5cil ( light1 & produces a spot1 kn[n by its be+ always 9 ! same "p ( ! plate2 occasionally ! door works too tightly s t small p>ticles ( wood1 etc41 are scrap$ (f1 & project$ aga9/ ! plate :5 x is rais$4 ,or p]haps ! op]ator1 aft] ! exposure is f9i%$1 %uts d[n ! door ) a j]k1 & s causes a spla% 9 ! liquid :i* has dra9$ d[n & accumulat$ 9 ! groove bel[2 ?is cause1 al?\gh n a common "o1 may sometimes occur4 #e4 ,insoluble p>ticles 9 ! ,pyrogallic ,acid4--,! solution ( ,pyrogallic ,acid w n usually require filt]+1 b if specks ( ,metagallic ,acid are pres5t1 ! develop] %\ld be pass$ ?r\gh blott+ pap] be=e use4 ,spots ( ,transp>5cy may g5]ally be trac$ to "s cause :i* r5d]s ! ,iodide ( ,silv] ins5sible to light at p>ticul> po9ts1 s t on ! application ( ! develop] no r$uction takes place4 #a4 ,conc5tration ( ! ,nitrate ( ,silv] on ! surface ( ! film by evaporation4--,:5 ! film becomes too dry aft] removal f ! ,ba?1 ! solv5t p[] ( ! ,nitrate increases s mu* t x eats away ! ,iodide & produces spots4 #b4 ,small p>ticles ( undissolv$ ,iodide ( ,potassium 9 ! ,collodion4--,^! are likely to occur :5 ,anhydr\s ,e!r & ,alcohol are employ$4 ,!y produce transp>5t specks at e "p ( ! plate4 ,all[ ! ,collodion to settle1 or add a drop ( wat]1 :i* w dissolve ! ,iodide4 #c4 ,alcohol or ,e!r conta9+ too mu* wat]4--,?is causes a reticulat$ appe>ance ( ! film1 :i* is rott5 & full ( holes4 #d4 ,use ( glasses improp]ly clean$4--,?is cause is p]haps ! mo/ frequ5t ( all1 :5 ! film ( ,pyroxyl9e is v ?9 & ! ,ba? neutral4 ,aft] glasses h be5 long us$ x is (t5 difficult to clean !m s ?or\ghly t ! brea? lies smoo?ly2 b ! use ( ,pota% gives ! be/ *ance4 ,,m>k+s ,,( ,,v>i\s ,,k9ds ,,on ,,collodion ,,plates4 #a4 ,a reticulat$ appe>ance on ! film aft] develop+4--,:5 ?is is univ]sal1 x (t5 dep5ds ^u ! employm5t ( ,collodion conta9+ wat]4 ,or1 if n due to ?is cause1 ! plate may h be5 imm]s$ too quickly 9 ! ,ba?1 & ! soluble ,pyroxyl9e p>tially precipitat$4 #b4 ,oily spots or l9es4--a4 ,f rais+ ! plate out ( ! ,nitrate ,ba? be=e x has be5 imm]s$ suffici5tly long to h become ?or\ghly wett$4--b4 ,removal ( ! plate f ! ,ba? be=e ! ,e!r ^u ! surface has be5 wa%$ away4--c4 ,r$ipp+ ! plate 9 ! ,nitrate ,ba? aft] exposure to light1 & p\r+ on ! develop] imm$iately2 if a few m9utes be n all[$ to dra9 (f ! excess ( ,nitrate1 ! ,pyrogallic ,acid w n amalgamate readily ) ! surface ( ! film4--d4 ,f ! ,nitrate ,ba? be+ cov]$ ) an oily scum1 :i* is c>ri$ d[n by ! plate4 ,draw a slip ( blott+-pap] g5tly along ! surface ( ! liquid be=e us+ x4 #c4 ,/raight l9es trav]s+ ! film horizontally4--,f a *eck hav+ be5 made 9 imm]s+ ! plate 9 ! ,ba?4 #d4 ,curv$ l9es ( ov]-developm5t4--,by employ+ ! develop] too conc5trat$2 or by n p\r+ x on suffici5tly quickly to cov] ! surface be=e ! action beg9s2 or by us+ too little ,acetic ,acid1 & omitt+ ! ,alcohol4 ,! addition ( ,alcohol to ! develop] w n be requir$ z a rule :5 ! ,ba? is newly made2 b :5 mu* ,e!r has accumulat$ 9 x1 ! develop] has a t5d5cy to run into oily l9es1 unless conta9+ ,alcohol4 #e4 ,/a9s f too small a quantity ( fluid hav+ be5 employ$ to develope ! image4--,9 ?is case1 ! :ole plate n be+ ?or\ghly cov]$ dur+ ! developm5t1 ! action does n always proce$ ) regul>ity4 #f4 ,irregul> /ri4--,f fragm5ts ( dri$ ,collodion accumulat+ 9 ! neck ( ! bottle1 & be+ wa%$ on ! film2 to avoid ?is1 ! f+] %\ld be pass$ g5tly r\nd ! inside ( ! neck be=e use4 #g4 ,m>k+s l ^? repres5t$ 9 ! woodcut4--,!y are caus$ by us+ an inf]ior sample ( ,pyroxyl9e made f too hot acids1 & are mo/ se5 :5 us+ an old ,ba?4 ,illu/ration #h4 ,/a9s on ! upp] "p ( ! plate1 f us+ a dirty slide4--,to avoid ^!1 place1 if necess>y1 /rips ( blott+-pap] betwe5 ! supports & ! glass4 #i4 ,wavy m>ks at ! l[] p>ts ( ! plate4--a4 ,if ! ,collodion is becom+ ?ick & glut9\s f con/ant use1 dilute x ) a little ,e!r conta9+ an eigh? "p ( ,alcohol4--b4 ,f rev]s+ ! direction ( ! plate aft] its removal f ! ,ba?1 s t ! ,nitrate ( ,silv] fl[s back aga9 ov] ! surface & causes a /a9 on ! application ( ,pyrogallic ,acid4--c4 ,impurities on ! woodwork ( ! frame asc5d+ ! film by capill>y attraction4 ,?is is a frequ5t s\rce ( /a9s4 #aj4 ,m>ks f ! develop] n runn+ up to ! edge ( ! film 7p4 #bab74 ,rem$y ?is z f> z possible by all[+ ! ,collodion to set a little m firmly be=e dipp+ ! plate 9 ! ,ba?4 ,,imp]fections ,,9 ,,collodion ,,negatives4 #a4 ,a want ( ,int5sity4--a4 ,f ! developm5t n hav+ be5 suffici5tly pu%$ 7p4 #bbd74--;b4 ,f ! ,collodion film be+ too blue & transp>5t = ,negatives4--c4 ,! ,collodion newly made f pure mat]ials 7p4 #aad74--;d4 ,! plate kept too long betwe5 excit+ & developm5t 7p4 #ajj74--;e4 ,! ,ba? newly prep>$ f comm]cial cry/alliz$ ,nitrate ( ,silv] 7p4 #aja74--;f4 ,! light too feeble1 z on v d>k w9try days1 or 9 copy+ int]iors1 etc4 #b4 ,inf]ior half-tones1 ) great int5sity ( ! high ,lights4--a4 ,f ! plate be+ insuffici5tly expos$4--b4 ,! ,collodion ( inf]ior quality1 ei!r too /rongly t9t$ ) ,iod9e or made f impure mat]ials4--c4 ,! ,nitrate ,ba? old & p>tially decompos$4--d4 ,! light reflect$ too /rongly f ! object4 ,:5 ! light is unusually bright1 a feeble ,collodion & a newly mix$ ,nitrate ,ba? w be f\nd to give bett] def9ition 9 ! high lights ?an an int5se ,collodion1 :i* may produce *alky ,negatives4 #c4 ,! image pale & mi/y4--,! plate is ov]-expos$ 7if s1 ! image w probably be a r$di%-br[n col\r by transmitt$ light71 or !re is diffus$ light 9 ! ,cam]a or develop+ room4 ,! pres5ce ( ,bromides or ,*lorides 9 ! ,collodion may occasionally produce ! same effect4 #d4 ,! high lights ( ! image are sol>iz$4--,a *ange ( col\r to a light br[n or r$ t9t by transmitt$ light1 ) a d>k %ade by reflect$ light1 is fav\r$ by ov]-exposure ( ! plate1 by organic decomposition ( ! ,collodion1 & by ,acetate ( ,silv] & o!r organic bodies 9 ! ,ba?4 #e4 ,! image dissolves (f on apply+ ! ,cyanide ( ,potassium4--,! ,collodion is probably ov]-iodiz$4 ,! same ?+ may also happ5 9 ! ,honey pres]vative process1 :5 ! plates h be5 long kept & ! indurat$ lay] ( syrup n prop]ly remov$ be=e apply+ ! develop]4 #f4 ,! develop] does n run up to ! edge ( ! film4--,?is is likely to occur :5 us+ ,collodion ne>ly anhydr\s2 & p>ticul>ly s ) a new ,ba? n conta9+ mu* ,alcohol4 ,! film w be less repell5t1 if a long] "t be all[$ be=e dipp+ 9 ! ,ba?4 #g4 ,! film does n /ick to ! glass4--,clean ! plates v c>efully1 & make ! ,collodion a little ?9n] if requir$4 ,all[ a long] "t be=e dipp+ 9 ! ,ba?4 ,a v effectual plan is to r\gh5 ! surface ( ! plates1 ab\t an eigh? ( an in* r\nd ! edges4 ,,imp]fections ,,9 ,,collodion ,,positives4 ,! pr9cipal difficulty 9 ! production ( ,negatives is to asc]ta9 ! "r "t ( exposure to light & ! prop] po9t to :i* to c>ry ! developm5t ( ! image4 ,a m9or am\nt ( fogg+1 /a9s1 etc41 is ( less consequ5ce1 & w sc>cely be notic$ 9 ! pr9t+4 ,) direct ,positives h[ev] ! case is diff]5t4 ,! beauty ( ^! pictures dep5ds entirely ^u _! be+ clean & brilliant1 )\t fogg+1 specks1 or imp]fections ( any k9d4 ,on ! o!r h&1 ! exposure & developm5t ( ,positives is comp>atively simple & easily asc]ta9$4 #a4 ,! %ad[s d>k & heavy4--,! plate has n receiv$ suffici5t exposure 9 ! ,cam]a2--or ! film be+ v transp>5t & ! ,silv] solution weak1 ,nitric ,acid is pres5t 9 ! ,ba?1 or ! ,collodion is br[n f free ,iod9e2 9 ! latt] case make ! ,collodion a little ?ick]1 & develope ) ,sulphate ( ,iron 9 pref]5ce to ,pyrogallic ,acid4 #b4 ,! %ad[s good1 b ! lights ov]done4--,! develop+ fluid may h be5 kept on too long2 or ! object is n prop]ly illum9at$ 7p4 #bbj72 or ! ,collodion is n adapt$ = ,positives4 #c4 ,! high lights pale & flat1 ! %ad[s mi/y4--,! plate is ov]-expos$4 ,indi/9ctness ( outl9e caus$ by ov]-exposure is di/+ui%$ f t produc$ by fogg+ by hold+ ! plate up to ! light2 9 ! =m] case ! image %[s z a ,negative4 ,if ! ,collodion is col\rless1 cle>] %ad[s w probably be obta9$ by dropp+ 9 ,t9cture ( ,iod9e until a yell[ col\r is produc$4 #d4 ,! picture developes sl[ly2 spangles ( metallic ,silv] are =m$4--,too mu* ,nitric ,acid is pres5t 9 proportion to ! /r5g? ( ! ,ba?1 to ! am\nt ( ,iodide 9 ! film1 & to ! quantity ( ,protosalt ( ,iron 9 ! develop] 7p4 #aab74 #e4 ,circul> spots ( a black col\r aft] hack+ up ) ! v>ni%4--,^! are (t5 caus$ by lift+ ! plate too quickly out ( ! ,ba?2 or by p\r+ on ! develop] at "o spot1 s z to wa% away ! ,nitrate ( ,silv]2 or by ! use ( glasses imp]fectly clean$4 #f4 ,! image becomes metallic on dry+4--,if ,sulphate ( ,iron is employ$1 ! solution is too weak1 or free ,nitric ,acid has be5 add$ 9 excess4 ,if ,pyrogallic ,acid is us$ to develope1 ! proportion ( ,nitric ,acid is too great4 #g4 ,a gre5 or blue t9t 9 c]ta9 p>ts ( ! image4--,?is is caus$ by ! deposit ( ,silv] be+ too scanty1 :i* may happ5 f ov]-action ( ! light1 or f ! film ( ,pyroxyl9e be+ v ?92--if ! ,collodion is dilut$ d[n beyond a c]ta9 po9t1 ! same quantity ( free ,nitrate ( ,silv] is n reta9$ ^u ! surface ( ! film4 ,add a few drops ( ! ,ba? to ! develop] be=e p\r+ x on ! plate4 #h4 ,v]tical l9es1 & mi/9ess1 on ! image4--,if ! ,ba? has be5 mu* us$1 add to x a ?ird "p ( a simple solution ( ,nitrate ( ,silv] 9 wat]1 )\t any ,alcohol or ,iodide4 ,also prep>e ! develop] ) addition ( ,alcohol1 to make x fl[ m readily 7p4 #baa74 ,,section ,,ii4 ,imp]fections 9 ,pap] ,positives4 #a4 ,! ,pr9t m>bl$ & spotty4--,! quality ( ! pap] is (t5 inf]ior1 :i* causes x to imbibe liquids unev5ly at diff]5t po9ts2 or ! am\nt ( ,silv] 9 ! ,nitrate ,ba? is insuffici5t4 ,9 ?is case ! spots are (t5 abs5t at ! l[] & mo/ dep5d+ "p ( ! %eet1 :]e ! excess ( liquid dra9s (f4 #b4 ,! ,pr9t clean on ! surface1 b spott$ :5 held up to ! light4--,9 ?is case ! spots are probably due to imp]fect fixation 7see p4 #abi74 #c4 ,! ,pr9t becomes pale 9 ! ,hyposulphite ,ba?1 & has a cold & fad$ appe>ance :5 f9i%$4--,! ,*loride ( ,silv] 9 ! pap] may h be5 9 excess ) reg>d to ! free ,nitrate ( ,silv]2 :i* is especially likely if no bronz+ c\ld be obta9$ by prolong$ action ( ! light1 or if a weak solution ( ,nitrate ( ,silv] 0 laid on ) a bru%1 or by a glass rod4 ,pr9ts =m$ on pap] :i* has be5 kept too long aft] s5sitiz+ pres5t ! same appe>ance1 ! free ,nitrate ( ,silv] hav+ ent]$ into comb9ation ) ! organic matt]4 #d4 ,yell[ness ( ! light p>ts ( ! pro(4--,! foll[+ causes are likely to produce yell[ness3--acidity ( ! fix+ & ton+ ,ba? 7p4 #aci71--;its action cont9u$ = too long a "t1--! fir/ wa%+s ( ! pro( n p]=m$ quickly1--! ton+ ,ba? laid aside until x _h become decompos$ & ne>ly useless1--! pap] kept = sev]al days aft] s5sitiz+4 ,a creamy yell[ness is also common 9 ,pr9ts ton$ by ,sel d'or1 :5 ! ,hydro*loric ,acid has be5 omitt$ f ! =mula2 ! pro( expos$ to light dur+ ! ton+ & fix+ process2 or too long a "t all[$ to elapse betwe5 ! ton+ & fix+4 ,x is also m frequ5tly met ) on album9iz$ pap]4 #e4 ,int5se bronz+ ( ! deep %ad[s4--,9 ?is case ! ,negative is 9 fault2 rem$y ! evil z f> z possible by pr9t+ on pap] conta9+ b little salt4 #f4 ,! def9ition ( ! ,pr9t imp]fect1 ! ,negative be+ a good "o4--,mu* w dep5d ^u ! quality ( ! pap]4 ,t[good's ,positive gives good def9ition4 ,! use ( ,album5 w be a great advantage4 ,citrate ( ,soda 7p4 #bdf7 w also improve ! def9ition on pla9 pap]4 #g4 ,m>k+s ( a yell[ t9t 9 ! d>k portions ( ! ,positive4--,^! are common on ,pr9ts ton$ )\t ,gold2 c>e %\ld be tak5 n to h&le ! pap] too mu*1 ei!r be=e or aft] s5sitiz+2 to wa% ! pr9ts 9 a clean vessel2 & n to lay !m d[n :il/ wet on a wood5 table or 9 contact ) any?+ likely to communicate impurities4 #h4 ,small specks & spots ( diff]5t h9ds4--,^!1 :5 n correspond+ to simil> m>ks ^u ! ,negative1 are usually due to metallic specks 9 ! pap]2 or to insoluble p>ticles float+ 9 ! ba?4 #i4 ,m>k+s ( ! bru% 9 ,ammonio-,nitrate pictures4--,9 ?is case !re is probably an excess ( ,ammonia1 :i* dissolves ! ,*loride ( ,silv]4 ,add a little fre% ,nitrate ( ,silv]1 or use ! ,oxide ( ,silv] dissolv$ 9 ,nitrate ( ,ammonia 7p4 #bdi74 #aj4 ,m>bl$ /a9s on ! surface ( ! ,pr9t4--,draw a /rip ( blott+-pap] g5tly ov] ! surface ( ! ,nitrate ,ba? be=e s5sitiz+ ! pap]2 & see t ! %eet does n t\* ! bottom ( ! di%4 #aa4 ,/reaks on ,album9iz$ pap]4--,apply ! ,album5 m rapidly & ev5ly to ! pap]4 ,if ?is does n succe$1 add a little ,ox-,gall 7p4 #bdc74 #ab4 ,removal ( ! ,album5 f ! pap] dur+ s5sitiz+4--,! ,nitrate ,ba? is probably alkal9e 7see page #hi74 ,,*apt] ,,vi4 ,,l&scape ,,photography ,,on ,,pres]v$ ,,collodion ,,& ,,collodio-,,album54 ,! ,collodion process may be appli$ ) success to l&scape ,photography2 b z ! plates become dry & lose _! s5sitiv5ess %ortly aft] _! removal f ! ,ba?1 ! op]ator w require to provide himself ) a yell[ t5t or "s portable vehicle 9 :i* ! op]ations ( s5sitiz+ & develop+ c be conduct$4 ,z x is a po9t ( great importance 9 ! ,collodion process t ! plate %\ld receive exactly ! "r am\nt ( exposure 9 ! ,cam]a1--a few seconds m or less suffic+ to affect ! "* ( ! picture1--_m w submit to mu* tr\ble & inconv5i5ce 9 ord] to h ! app>atus complete ^u ! spot at :i* ! view is tak54 ,! object ( ! ,collodion ,pres]vative ,processes is to ma9ta9 ! s5sitiv5ess ( ! film = a c]ta9 l5g? ( "t aft] x has be5 excit$ 9 ! ,ba?4 ,!re is "s difficulty 9 do+ ?is1 because if ! plate be all[$ to dry spontane\sly1 ! solution ( free ,nitrate ( ,silv] ^u ! surface1 becom+ conc5trat$ by evaporation1 eats away ! ,iodide ( ,silv]1 & produces transp>5t spots4 ,"s op]ators h attempt$ to use a second plate ( glass 9 su* a way z to enclose ! s5sitive film ) an int]v5+ /ratum ( liquid4 ,! difficulty h[ev] ( sep>at+ ! glasses aga9 )\t te>+ ! film1 is consid]able4 ,9 ! process ( ,messrs4 ,spill] & ,crookes1 ! prop]ty possess$ by c]ta9 sal9e sub/ances ( rema9+ = a long "t 9 a moi/ condition 0 turn$ to acc\nt4 ,su* salts are t]m$ deliquesc5t1 & _m ( !m h s great an attraction = wat] t !y absorb x eag]ly f ! air3 ! solution hav+ be5 =m$1 ! wat] _c entirely be driv5 (f except by ! application ( a consid]able heat4 ,m rec5tly1 ,honey has be5 employ$ by ,mr4 ,%adbolt4#eb ,?is sub/ance c sc>cely be t]m$ deliquesc5t1 b x possesses1 l o!r uncry/allizable sug>s1 ! prop]ty ( rema9+ moi/ & /icky = a long "t4 ,honey is1 accord+ to ! ,au?or's views1 sup]ior to inorganic deliquesc5t salts z a pres]vative ag5t1 f its possess+ an aff9ity = ,oxides ( ,silv]1 & ?us act+ *emically 9 communicat+ organic int5sity to ! image4--,collodion plates :5 kept long 9 a moi/ & s5sitive /ate (t5 give a pale & blue image1 ev5 al?\gh ! ,nitrate ( ,silv] be left ^u ! film2 & nei!r ,nitrate ( ,magnesia nor ,glyc]9e appe>s capable ( supply+ ! defici5t elem5t1 bo? be+ ne>ly or q indiff]5t to ! ,salts ( ,silv]4 #eb ,a claim has lately be5 advanc$ by ,mr4 ,maxwell ,lyte to be consid]$ z ! discov]] ( ! ,honey ,process4 ,?is g5tleman appe>s to h work$ simultane\sly ) ,mr4 ,%adbolt1 & to h anticipat$ him 9 publi%+2 b ! object ( ,mr4 ,lyte's process 0 r to increase ! s5sibility ( ! plates ?an to conf] ^u !m keep+ qualities4 ,,! ,,honey ,,& ,,oxymel ,,keep+ ,,processes4 ,:5 ! wea!r is cool1 ,collodion plates may be pres]v$ ) tol]able c]ta9ty = a few h\rs1 by simply apply+ ,honey to !m 9 ! /ate 9 :i* !y are tak5 f ! ,nitrate ( ,silv] ,ba?4 ,! be/ pure ,virg9 ,honey %\ld be obta9$ by dripp+ x imm$iately f ! comb4 ,?is po9t is ( importance1 s9ce if ! sample ( honey be ( inf]ior quality1 or adult]at$1 ! process may n succe$4 ,! quantity ( wat] to be add$ w v>y ) ! consi/5ce ( ! honey1 f ab\t an equal bulk to two p>ts3 x %\ld be suffici5t to make ! pres]vative solution pass sl[ly ?r\gh filt]+-pap]4 ,aft] ! plate is remov$ f ! ,nitrate ,ba?1 x is to be dra9$ & wip$ on ! back 9 ! usual way4 ,! ,honey is !n p\r$ along ! edge 9 su* a mann] z to =m a broad wave :i* =ces ! ,nitrate ( ,silv] solution be=e x & cov]s ! film4 ,next dra9 ! plate into a measure & p\r on a second portion ( ,honey z be=e4 ,?is second dose may be us$ aga9 = ! fir/ application to ! succe$+ plate4 ,la/ly1 /& ! glass on blott+-pap] 9 a d>k place = ab\t a qu>t] ( an h\r or tw5ty m9utes1 & wipe ! l[] edge be=e putt+ x into ! plate box4 ,! exposure requir$ w probably be ab\t f\r or five times z long z t = new & s5sitive ,collodion1 or twice z long z ! exposure requir$ = old & br[n ,collodion4 ,be=e apply+ ! develop]1 imm]se ! plate 9 a ,ba? ( ra9-wat] = five m9utes1 mov+ x ab\t occasionally to s(t5 ! honey4 ,?is w probably be suffici5t = plates :i* h n be5 kept long] ?an f\r h\rs1 & beyond t "t ! process is n consid]$ c]ta91 s9ce ! ,honey ex]cises a sl[ r$uc+ action ^u ! ,nitrate ( ,silv]4 ,! solution ( ,pyrogallic ,acid may be us$ ( ! ord9>y /r5g?1 ) a full dose ( ,acetic ,acid4 ,only a fa9t image comes out at fir/1 b on p\r+ ov] ! plate a fre% portion ( ! develop] ) two or ?ree drops ( ! ,nitrate ,ba? add$ to ea* fluid dra*m1 x may be int5sifi$ to any ext5t4 ,fix ) ,hyposulphite ( ,soda1 & wa% 9 ! usual way4 ,:5 ! process fails1 f heat ( ! wea!r or o!r causes1 ! image w probably be feeble & r$ by transmitt$ light1 & ! %ad[s defective & mi/y4 ,?is is especially likely to happ5 :5 ! ,nitrate ,ba? is v old & conta9s mu* ,acetate ( ,silv]2 or :5 ! same portion ( ,honey is us$ m ?an once1 & has und]gone p>tial decomposition by ! action ( ! ,nitrate ( ,silv]4 ,! use ( pure ,honey1 free f m\ld9ess & f]m5tation1 w1 9 cool wea!r1 almo/ c]ta9ly ensure success4 ,a modification ( ! process :5 ! plates are to be kept ov] f\r h\rs4--,9 ?is case ! :ole1 or ! great] "p ( ! ,nitrate ( ,silv] mu/ be remov$ be=e apply+ ! pres]vative ag5t4 ,wa% ! s5sitive plate 9 wat] 9 ! mann] describ$ = ! ,oxymel process 9 ! next page4 ,!n apply ! syrup z be=e1 us+ x z ?ick z possible4 ,honey$ plates1 free f ,nitrate ( ,silv]1 may commonly be kept = five or six days2 (t5 mu* long]4 ,dr4 ,mansell1 :o has employ$ ?is process ) great success1 speaks ( temp]ature z a po9t to be att5d$ to4 ,9 hot wea!r ! same l5g? ( keep+ prop]ties w n be atta9$4 ,use ( ,oxymel = pres]v+ ,collodion plates4--,! pr9cipal difficulty 9 ! employm5t ( ,honey 9 ,photography1 is its disposition to f]m5t1 or to become m\ldy4 ,f]m5tation occurs mo/ readily 9 a dilute solution1 & w be obviat$ by us+ ! syrup z ?ick & free f wat] z possible4 ,mr4 ,llewellyn employs ,oxymel1 :i* is a mixture ( ,honey & ,v9eg>1 z a pres]vative ag5t4 ,?is sub/ance w keep ev5 9 dilute solution = a long "t )\t decomposition2 &1 be+ v readily remov$ f ! plates1 does n int]f]e ) ! developm5t ( ! image4 ,! prep>ation ( ,oxymel is describ$ 9 ! ,vocabul>y1 ,"p ,,iii42 x mu/ be dilut$ ) ?ree or f\r p>ts ( wat]1 & filt]$4 ,c]ta9 facts to :i* att5tion has be5 lately drawn by ,dr4 ,norris & ,mr4 ,b>nes 9 work+ ) dry ,collodion1 may be advantage\sly borne 9 m9d :5 us+ ,oxymel2 ! pres]vative solution ( :i* is employ$ 9 s dilute a /ate t ! process resembles to a great ext5t a dry ,collodion process4 ,! obs]vations above ref]r$ to relate to ! quality ( ! ,collodion be/ adapt$ = ! purpose1 & w be f\nd at page #bih1 to :i* ! read] is ref]r$4 ,! manipulation ( ! ,oxymel process is v simple4 ,two flat gutta-p]*a di%es are provid$1 ! "o conta9+ common wat] & ! o!r dilut$ & filt]$ ,oxymel4 ,! ,collodion plate1 on its removal f ! ,ba?1 is plac$ 9 ! fir/ di%1 :i* is g5tly tilt$ up & d[n1 to wa% away ! free ,nitrate ( ,silv]4 ,9 a few seconds1 :5 ! liquid is r5d]$ milky1 x is p\r$ away1 & fre% wat] be+ introduc$1 ! process is repeat$ until ! oily l9es disappe>1 & ! surface ( ! film becomes smoo? & glassy4 ,! plate is !n1 aft] a slight dra9+1 remov$ to ! second tray1 & ! ,oxymel wav$ backw>ds & =w>ds = ab\t half a m9ute1 aft] :i* ! glass is lift$ out & plac$ v]tically on blott+-pap]1 :i* mu/ be r5ew$ :5 x becomes wet & saturat$4 ,! plates may be us$ any "t )9 a =tnight f ! date ( _! prep>ation1 & x is n necess>y to develope imm$iately aft] ! exposure4 ,! s5sitiv5ess w be consid]ably less ?an t ( fre% ,collodion3 f two to five m9utes may be all[$ ) a ,/]eoscopic view l5s hav+ a qu>t]-in* diaphragm4 ,be=e develop+1 ! film %\ld be g5tly wa%$ = a few seconds ) common wat]4 ,solution ( ,pyrogallic ,acid1 ( ! ord9>y /r5g?1 b previ\sly mix$ ) a portion ( ! ,nitrate ,ba? solution1 "o or two drops to ea* dra*m1 may !n be p\r$ on 9 ! ord9>y way4 ,use less ,nitrate ( ,silv] & m ,acetic ,acid 9 hot wea!r4 ,:5 discoloration ( ! develop] occurs1 mix a fre% portion & proce$ z be=e4 ,,precautions ,,to ,,be ,,obs]v$ ,,9 ,,keep+ ,,processes4 ,! plates mu/ be r\gh5$ at ! edges1 & also ^u ! surface1 to make ! film adh]e4 ,x is advisable to use a tol]ably ?ick ,collodion1 giv+ a yell[ film2 ! pale opalesc5t films be+ m easily affect$ by m>k+s on ! glass1 & n reta9+ s mu* ( syrup or ,nitrate ( ,silv] ^u ! surface4 ,! room 9 :i* ! plates are prep>$ mu/ be c>efully gu>d$ f scatt]$ p5cils ( :ite light2 ! films are expos$ to injury f ?is cause dur+ ! :ole ( ! "t occupi$ 9 apply+ ! pres]vative syrup2 & h5ce any?+ %ort ( absolute *emical d>kness w be likely to cause fogg+2 especially s :5 free ,nitrate ( ,silv] is left ^u ! film4 ,! wat] us$ = wa%+ away ! free ,nitrate ( ,silv] be=e apply+ ! pres]v+ liquid1 ne$ n be di/ill$4 ,common h>d wat] conta9+ ,c>bonates & ,*lorides1 & produc+ milk9ess ) ,nitrate ( ,silv]1 w (t5 suffice4 ,! wat] ( ! ,new ,riv] & ( ! ,riv] ,?ames1 ) :i* _m p>ts ( ,london are suppli$1 may c]ta9ly be us$2 b 9 ! case ( a v h>d wat]1 conta9+ mu* ,sulphate ( ,lime1 x might p]haps be advisable to sub/itute clean ra9-wat]1 free f br[n organic discoloration4 ,! pres]vative ,oxymel mu/ be c>efully filt]$1 & kept cov]$1 9 ord] to protect x f du/4 ,x w also be necess>y occasionally1 be=e us+ x1 to run x ?r\gh a piece ( :ite cambric1 to /op back susp5d$ p>ticles1 :i*1 if all[$ to rema91 w\ld be a s\rce ( spots4 ,if x becomes m\ldy1 or discol\r$ by ,silv]1 or f]m5ts & evolves gas1 ?r[ x away4 ,aft] ! syrup is appli$ & ! plates are dra9$1 /[ !m 9 a groov$ box p]fectly protect$ f light2 or place !m 9 slides1 :i* mu/ be kept scrupul\sly clean1 s9ce any trace ( impurity w\ld be likely to produce a /a9 :5 ! plate 0 left a long "t 9 ! slide4 ,if ! pres]v$ plates are kept 9 a cupbo>d or box1 see t no volatile matt]1 su* z ,ammonia1 coal-gas1 etc41 c f9d entrance4 ,9 *ang+ ! plates aft] ! exposure 9 ! ,cam]a1 use a l>ge bag made ( sev]al ?icknesses ( black calico1 ) a squ>e ( yell[ calico let 9 at ! top2 an ela/ic b& secur+ x r\nd ! wai/4 ,,! ,,collodio-,,album5 ,,process4 ,?is process1 ! !ory ( :i* has be5 briefly expla9$ at page #aha1 is m s5sitive ?an ! "o la/ describ$1 & has ! additional advantage ( giv+ dry plates1 :i* d n attract du/1 & are less liable to injury4 ,! details ( manipulation are complex1 b ?is inconv5i5ce is n s mu* felt :5 prep>+ a l>ge numb] ( plates4 ,clean+ ! ,glasses4--,success w greatly dep5d ^u ! mode 9 :i* ?is "p ( ! process is p]=m$4 ,! lay] ( ,album5 :i* is appli$ to ! ,collodion film t5ds to swell & to raise ! latt] 9 bli/]s2 ! mo/ effectual mode ( obviat+ :i* w be to clean ! glass s t ! film adh]es ) unusual t5acity4 ,! ,liquor ,potass ( ! ,druggi/s1 dilut$ ) ?ree or f\r p>ts ( wat]1 & rubb$ on ! glass by a roll ( flannel 7page #bad71 is v effectual4 ,a mixture ( ,tripoli-wat] & ,nitric ,acid may h[ev]1 if desir$1 be sub/itut$3-- ,tripoli #a dra*m4 ,nitric ,acid #cj m9ims4 ,wat] #a ounce4 ,lay ! glass flat on a clo?1 & rub ! surface c>efully ) a tuft ( cotton-wool dipp$ 9 ! ,tripoli2 !n1 be=e ! cream dries1 wipe x (f ) a second tuft1 & poli% ) a ?ird4 ,la/ly1 brea! ^u ! glass1 & hav+ asc]ta9$ t x is *emically clean1 apply ! ,collodion4 ,coat+ ) ,collodion4--,*oose a r ?9 ,collodion :i* adh]es tightly to ! glass4 ,a prep>ation :i* has be5 kept a long "t aft] iodiz+ w usually answ] ! purpose v well1 &1 z a rule1 a non-contractile1 /ructureless ,collodion is bett] ?an "o :i* is glut9\s & wavy4 ,! degree ( s5sibility ( ! ,collodion is n ?\ght to h mu* influ5ce ^u ! result4 ,coat+ ! ,plate4--,apply ! ,collodion 9 ! usual mann]1 & all[ x full "t to set p]fectly1 be=e dipp+ 9 ! ,ba?1 9 ord] to fav\r its adh]5ce to ! glass4 ,) ,collodion prep>$ f anhydr\s spirits1 ab\t half a m9ute may be giv5 9 cool wea!r4 ,! ,nitrate ,ba?4--,take ( ,fus$ ,nitrate ( ,silv] #dj gra9s4 ,glacial ,acetic ,acid #cj m9ims4 ,alcohol #bj m9ims4 ,wat] #a fluid ounce4 ,saturate ) ,iodide ( ,silv] z describ$ at page #bjd1 & filt]4 ,an imm]sion ( "o m9ute w be suffici5t2 aft] :i*1 give ! plate an up-&-d[n movem5t1 & wa% x 9 pla9 wat]1 9 ! mann] advis$ = ! ,oxymel pres]vative process1 at page #bib4 ,!n /& x on blott+-pap]1 to dra9 = a m9ute or two1 wipe ! back ( ! glass1 & p\r on ! ,album54 ,?is ,ba? may become discol\r$ aft] a "t2 cont9ue to use x until x is ( a d>k %]ry-col\r1 & !n treat x ) ,kaol91 9 ! mann] & ) ! precautions advis$ at pages #ia & #bde4 ,! ,iodiz$ ,album54--,procure eggs1 fre% laid1 or n m ?an two or ?ree days old4 ,sep>ate ! :ites 9 ! same way z = ,album9iz$ pap] 7p4 #bda71 & mix by ! foll[+ ,=mula3-- ,album5 #i fluid ounces4 ,wat] #c fluid ounces4 ,liquor ,ammoni #b fluid dra*ms4 ,iodide ( ,potassium #dh gra9s4 ,bromide ( ,potassium #ab gra9s4 ,! ,iodide & ,bromide %\ld be free f ,c>bonate ( ,pota%1 :i* is said to cause p9-holes 9 ! ,negatives4 ,to ensure ! abs5ce ( ?is salt1 dissolve ! total quantity ( bo? ,iodide & ,bromide 9 ! ?ree ounces ( wat] advis$ 9 ! =mula2 !n1 previ\sly to add+ ! ,ammonia & ,album51 introduce an excessively m9ute p>ticle ( ,iod9e1 en\gh b>ely to col\r ! liquid4 ,! ,iod9e decomposes ! ,c>bonate ( ,pota%1 b x mu/ n be us$ 9 excess1 s9ce free ,iod9e possesses ! prop]ty ( coagulat+ ,album54 ,iodide ( ,cadmium also coagulates ,album51 s t ! ,iodides ( ,potassium & ,ammonium are ! be/4 ,hav+ mix$ ! +r$i5ts 9 ! ord] above giv51 introduce !m into a bottle1 & %ake x viol5tly until !y h ?or\ghly amalgamat$4 ,!n transf] to a tall n>r[ j>2 all[ to settle = tw5ty-f\r h\rs1 & draw (f ! upp] cle> portion = use4 ,p>ticul>s ( ?is "p ( ! process h already be5 giv5 "u ! head ( ,album9iz$ ,pap]1 to :i* ! read] is ref]r$ 7p4 #bda74 ,! ammoniacal solution ( ,album5 may be kept = "s "t 9 a /opp]$ bottle )\t mu* decomposition4 ,if muc\s ?reads =m 9 x1 filt] ?r\gh f9e l954 ,mode ( apply+ ! ,album54--,cov] ! moi/ film ) ! ,album5 9 ! same way z advis$ = ,collodion 7p4 #baf71 p\r+ on at once a suffici5t quantity to cause x to spread 9 an ev5 & undivid$ %eet2 o!rwise a ve9$ appe>ance may be produc$1 :i* w %[ 9 ! developm5t4 ,return ! excess ( ,album5 into ! bottle1 & p\r x once aga9 ^u ! plate3 ! film w rema9 cle> & transp>5t1 if ! :ole ( ! ,nitrate ( ,silv] has be5 prop]ly wa%$ away f ! ,collodion4 ,la/ly1 /& ! plate ne>ly v]tically on blott+-pap] to dry4 ,?is w occupy five or six h\rs2 b ! process may be ha/5$ by artificial heat4 ,aft] ! ,album5 solution has be5 us$ to coat a numb] ( plates successively1 x becomes dilut$ ) wat]2 ! result ( :i* is1 t unequal int5sity ( image is produc$ at ! upp] & l[] edge ( ! film4 ,! iodiz$ ,album5 plates are at ?is /age ( ! process ne>ly or q ins5sitive to light1 & may be pres]v$ un*ang$ = _m weeks4 ,s5sitiz+ ! ,album5 film4--,:5 ! plate has become ?or\ghly dry1 x is aga9 introduc$ into ! ,ba? ( ,aceto-,nitrate ( ,silv]1 & all[$ to rema9 = "o m9ute3 !n wa%$ ) wat] 9 ! same mann] z be=e1 b ) ev5 great] c>e1 9 ord] to obviate cl\d+ 9 ! developm5t4 ,if bli/]s %\ld =m on dry+1 x w be f\nd useful to ha/5 ! process by hold+ ! plates to ! fire--or a hot iron may be plac$ 9 ! c5tre ( a cov]$ box & ! glasses re>$ up r\nd ! sides4 ,!y w ?us dry quickly1 & !re w n be "t = ! ,album5 to swell mu* by imbibition4 ,exposure 9 ! ,cam]a4--,?is may be p]=m$ at any p]iod )9 a few weeks f ! date ( prep>ation ( ! plates4 ,= a l&scape view ) a small ,/]eoscopic s+le l5s1 all[ ab\t ?ree m9utes 9 ! w9t]1 or "o m9ute & a half 9 ! summ]4 ,developm5t ( ! image4--,?is c be def]r$ z long z f\rte5 days aft] ! exposure1 ) successful results4 ,p\r wat] ov] ! plate until ! film is ?or\ghly wett$2 !n cov] x ) a solution ( ,pyrogallic ,acid conta9+ "o gra9 ( ! acid to ! ounce ( wat]1 & tw5ty m9ims ( ,glacial ,acetic ,acid4 ,two drops ( a neutral solution ( ,nitrate ( ,silv] made ) =ty gra9s ( ,nitrate to ! ounce ( wat] mu/ be previ\sly add$ to ea* fluid dra*m ( ! ,pyrogallic4 ,! developm5t1 9 ! case ( a l&scape view tak5 ) sunlight1 comm5ces almo/ imm$iately1 & may be complet$ 9 ab\t t5 m9utes1 b ! "t occupi$ 9 develop+ w v>y greatly ) ! l5g? ( exposure1 ! quantity ( ,nitrate ( ,silv]1 & ! nature ( ! subject copi$--a badly light$ int]ior1 = in/ance1 (t5 tak+ an h\r or long] to appe> 9 all its details4 ,if ! develop] %\ld discol\r be=e ! prop] int5sity has be5 obta9$1 p\r x (f & mix a fre% quantity4 ,fix+ ! image4--,hyposulphite ( ,soda 7"o ounce to f\r ( wat]7 w be f\nd pref]able to ! ,cyanide ( ,potassium1 z ! latt] has a solv5t effect ^u ! ,album54 ,an unusually long "t w be requir$1 z ! fix+ ag5t mu/ p5etrate ! ,album51 to rea* ! ,collodion b5ea?4 ,c>eful wa%+ 9 wat] = five or t5 m9utes removes ! excess ( ,hyposulphite1 & ! plate may !n be v>ni%$ 9 ! usual way4 ,,! ,,dry ,,collodion ,,process4 ,! e>li] attempts to employ s5sitive ,collodion plates 9 a desiccat$ condition 7 unsuccessful4 ,! film ( ,pyroxyl9e %r9ks on dry+1 & becomes almo/ imp]vi\s to moi/ure3 h5ce1 ! develop+ solution n p5etrat+ prop]ly1 d5sity _c easily be obta9$4 ,we are indebt$ to ,dr4 ,hill ,norris1 ( ,birm+ham1 = e/abli%+ ! !ory ( ! subject ^u a m correct basis4 ,he has po9t$ out ! importance ( di/+ui%+ two diff]5t conditions ( ! ,collodion surface1#ec viz4 ! contractile1 common 9 newly-mix$ ,collodion1--& ! %ort or p[d]y1 9 ,collodion :i* has be5 iodiz$ ) ! alkal9e ,iodides1 & kept until mu* ,iod9e has be5 set free4 ,! latt] is ! mo/ suitable condition = ! dry process2 & ! practical mode ( di/+ui%+ betwe5 !m is by s5sitiz+ a plate & pass+ ! f+] across x2 if x c be easily pu%$ away 9 a firm & connect$ sk91 x w be unfit = ! purpose requir$4 ,9 ord] /ill fur!r to pres]ve ! film 9 a condition p]meable by ! develop]1 x is recomm5d$ to coat x :il/ moi/ ) a solution ( ,gelat9e4 #ec ,see ^! /ates ( ! film m fully describ$ at page #hc4 ,! dry ,collodion process1 al?\gh less s5sitive1 is m simple ?an t on ,collodio-,album51 & possesses _m ( its advantages2 b x is less univ]sally applicable1 s9ce x dep5ds entirely = success ^u ! peculi> /ate ( ! ,collodion1 resembl+ 9 ?is respect ! ,oxymel process already describ$4 ,mode ( prep>+ ! plates4--,! glasses are coat$ ) ! ,collodion 9 ! usual way4 ,bli/]+ dur+ developm5t be+ liable to happ5 9 ?is process z 9 ! la/1 e c>e mu/ be tak5 to make ! films adh]e ) ! greate/ possible t5acity1 bo? by clean+ ! glasses ) extra c>e 7see p4 #bid71 & also by all[+ ! ,collodion to set firmly be=e dipp+ 9 ! ,ba?4 ,! plate may be held f tw5ty to ?irty seconds previ\s to imm]sion1 or ev5 long]1 provid$ ! film1 :5 lift$ out ( ! ,ba?1 appe>s ( uni=m ?ickness ?r\gh\t 7see page #bah74 ,! s5sitiz+ hav+ be5 complet$1 wa% ! plates ) pla9 wat]1 exactly 9 ! same way z = ,oxymel 7p4 #bib74 ,if ,nitrate ( ,silv] be left1 cl\d+ w take place 9 ! process ( developm5t4 ,aft] wa%+1 dra9 = a few seconds1 & imm]se 9 ! solution ( ,gelat9e4 ,to prep>e ?is ,ba?1 take ( ,nelson's pat5t ,gelat9e #abh gra9s4 ,di/ill$ wat] #ad ounces4 ,alcohol #b-a_/b ounces4 ,put ! ,gelat9e 9 ! cold wat]1 & all[ x a qu>t] ( an h\r to s(t5 & swell2 x w !n readily dissolve on apply+ a g5tle heat4 ,?is may be done 9 a glaz$ saucepan or a pipk9 ( e>!nw>e1 tak+ c>e n to scor* ! bottom "p by too /rong a heat4 ,next cl>ify ! solution by add+ to x1 :il/ b>ely w>m1 a tea-spoonful ( :ite ( egg 7previ\sly beat5 up ) a silv] =k71 & aft]w>ds heat+ ne>ly to ! boil+ po9t4 ,! ,alcohol mu/ n[ be add$1 to facilitate ! coagulation ( ! ,album54 ,:5 ?is takes place & ! liquid becomes cle>1 filt] ?r\gh a clean piece ( cambric fold$ ?ree or f\r times4 ,if a hot wat] filt]+ app>atus c be obta9$1 ! solution may be made to pass ?r\gh pap]2 b z x t5ds to gelat9ize on cool+1 ! ord9>y mode ( filtration commonly fails4 ,! quantity ( ,alcohol 9 ! above =mula is great] ?an is usually recomm5d$1 all[ance hav+ be5 made = a p>tial evaporation ( ! _s4 ,! filt]$ liquid may be p\r$ into a flat porcela9 di%1 or a v]tical tr\gh1 b 9 ei!r case x w be necess>y to /& ! vessel 9 w>m wat]1 9 ord] to prev5t gelat9ization4 ,! ,collodion plate1 ?or\ghly wa%$1 is to be imm]s$ 9 ?is solution & mov$ up & d[n = two or ?ree m9utes4 ,x is !n remov$1 dra9$ on blott+-pap]1 & dri$4 ,! use ( artificial heat 9 dry+ w be f\nd a great advantage2 x prev5ts ! gelat9e f settl+ unequally ^u ! plate4 ,^? :o possess an app>atus made purposely = dry+ plates by hot air1 w exp]i5ce no difficulty1 b an ord9>y deal trunk may be made to answ]1 ) a little managem5t4 ,cov] ! bottom ( ! box ) blott+-pap]1 & hav+ heat$ "o or two flat irons1 place !m 9 ! c5tre3 !n range ! glasses side by side1 ) ! coat$ surface look+ inw>ds2 9 a qu>t] ( an h\r1 or f t to tw5ty m9utes1 ! desiccation w be complete4 ,if ! ,collodion plates are prep>$ 9 a room conta9+ a fire1 !y may be re>$ up side by side at a di/ance ( two or ?ree feet1 & 9 t way may be safely dri$ )\t fe> ( injury1 provid$ :ite light be exclud$4 ,:5 dry !y c be /[$ away 9 a box2 all ! precautions giv5 at page #bic be+ obs]v$4 ,! s5sibility rema9s good = _m days1 possibly = weeks or mon?s 9 cold wea!r4 ,exposure 9 ! ,cam]a4--,all[ f f\r to eight times ! exposure ( ! mo/ s5sitive moi/ ,collodion4 ,on a cle> summ]'s day1 a sun-lit view may require "o m9ute or a m9ute & a half1 ) a %ort focus ,/]eoscopic l5s1 hav+ a diaphragm ( a qu>t] ( an in* diamet]4 ,! av]age "t h[ev] ) ! same l5s w\ld be ab\t twice z mu*1 viz4 ?ree m9utes4 ,developm5t ( ! ,image4--,make a saturat$ solution ( ,gallic ,acid 9 wat] by ! directions giv5 at page #bfa4 ,!n dissolve =ty gra9s ( pure ,nitrate ( ,silv] 9 "o ounce ( di/ill$ wat]4 ,p\r into a flat porcela9 di% a suffici5t quantity ( ! ,gallic ,acid solution to flood ! plate readily4 ,!n measure x1 & to ea* fluid ounce add t5 m9ims ( ! solution ( ,silv]1 or five m9ims 9 hot wea!r4 ,x is important t no discoloration %\ld occur on mix+ ^! liquids toge!r1 to obviate :i*1 obs]ve ! foll[+ precautions3--,clean ! porcela9 vessel v c>efully ) ,nitric ,acid or ,cyanide be=e use4 ,employ a pure solution ( ,nitrate ( ,silv]2 & mix x ) ! ,gallic ,acid1 9 pref]5ce to add+ ! ,gallic ,acid to ! ,silv] solution 7read ! rem>ks at p4 #agi74 ,! picture may be expect$ to appe> 9 five or t5 m9utes1 & 9 "o h\r1 or f t to f\r h\rs 7p4 #bih71 ! developm5t w be complete4 ,x w n be necess>y to keep ! plates 9 motion1 b simply to lay !m side by side 9 ! solution ( ! ,gallic ,acid4 ,if 9 spite ( all precautions ! develop] beg9s to black5 be=e ! int5sity has rea*$ ! prop] po9t1 x mu/ be p\r$ (f & a fre% mixture prep>$4 ,?is h[ev] w n (t5 happ54 ,la/ly1 :5 a full am\nt ( opacity has be5 obta9$1 wa% ! plate ) wat]1 & fix x 9 a solution ( ,hyposulphite ( ,soda1 or dilute solution ( ,cyanide ( ,potassium4 ,failures 9 ! process4--,/a9s 9 ! developm5t may arise f us+ dirty di%es1 or glasses :i* h be5 left 9 ,gallo-,nitrate ( ,silv] & improp]ly clean$4 ,x mu/ be borne 9 m9d t ^! impurities are n visible to ! eye1 al?\gh !y produce ! effect ( discol\r+ ! develop]4 ,a ?or\gh cleans+ ) /rong ,nitric ,acid or ,pota% w prove a rem$y4 ,bli/]s1 unless ( l>ge size1 may (t5 be disreg>d$1 z !y disappe> on dry+4 ,g5]al cl\d9ess may dep5d ^u ! film hav+ be5 imp]fectly wa%$4 ,irregul> r$uction at c]ta9 p>ts may be due to ! ,gelat9e sett+ be=e ! plate has become dry1 or to /a9s produc$ by ! f+] appli$ to ! upp] edge ( ! plate4#ed #ed ,s9ce ! above 0 writt51 ,mr4 ,maxwell ,lyte has communicat$ to ! ',photographic ,j\rnal' 7vol4 iii47 a dry process 9 :i* a modifi$ ,gelat9e is us$4 ,! *ange is produc$ by boil+ a solution ( gelat9e ) dilute ,sulphuric ,acid1 :i* is aft]w>ds neutraliz$ & remov$ by means ( *alk4 ,! result is to de/roy ! gelat9iz+ prop]ty ( ! animal sub/ance2 ! solution reta9s its fluidity on cool+1 & ! necessity ( employ+ artificial heat 9 dry+ ! plates is avoid$4 ,,"p ,,iii4 ,,outl9es or ,,g5]al ,,*emi/ry4 ,,outl9es or ,,g5]al ,,*emi/ry4 ,illu/ration ,,*apt] ,i4 ,,! ,,*emical ,,elem5ts ,,& ,,_! ,,comb9ations4 ,! limits ( ! pres5t ,"w all[ only ( a simple sket* ( ! subjects :i* x is propos$ to treat 9 ?is ,*apt]4 ,our att5tion !re=e mu/ be conf9$ to an explanation ( c]ta9 po9ts :i* are allud$ to 9 ! ,fir/ ,"p ( ! ,"w1 & )\t a prop] und]/&+ ( :i* x w be impossible = ! read] to make progress4 ,! foll[+ division may be adopt$3--,! m important ,elem5t>y ,bodies1 ) _! symbols & atomic weights2 ! ,comp\nds =m$ by _! union2 ! class ( ,salts2 illu/rations ( ! nature ( ,*emical ,aff9ity2 ,*emical ,nom5clature2 ,symbolic ,notation2 ! laws ( ,comb9ation2 ! ,atomic ,!ory2 ! ,*emi/ry ( ,organic ,bodies4 ,,! ,,*emical ,,elem5ts1 ,,) ,,_! ,,symbols ,,& ,,atomic ,,weights4 ,! class ( elem5t>y bodies embraces all ^? sub/ances :i* _c1 9 ! pres5t /ate ( our k1 be resolv$ into simpl] =ms ( matt]4 ,! *emical elem5ts are divid$ into metallic & non-metallic1 accord+ to ! possession ( c]ta9 g5]al *>act]s4 ,! foll[+ are "s ( ! pr9cipal non-metallic elem5ts1 ) ! symbols employ$ to designate !m1 & _! atomic weights3#ee-- ,symbol4 ,atomic ,wt4 ,gases4 ,oxyg5 ,o #h ,hydrog5 ,h #a ,nitrog5 ,n #ad ,*lor9e ,cl #cf ,solids4 ,iod9e ,i #abf ,c>bon ,c #f ,sulphur ,s #af ,phosphorus ,p #cb ,liquid4 ,brom9e ,br #gh ,unkn[n4 ,fluor9e ,f #ai ,! metallic elem5ts are m num]\s4 ,! foll[+ li/ includes only ^? :i* are commonly kn[n3-- ,symbol4 ,atomic ,wt4 ,metals ( ! ,potassium ,k #dj ,alkalies4 ,sodium ,na #bd ,metals ( ! ,b>ium ,ba #fi ,alkal9e ,calcium ,ca #bj ,e>?s ,magnesium ,mg #ab ,metals ,iron ,fe #bh ,prop]4 ,z9c ,zn #cb ,cadmium ,cd #ef ,copp] ,cu #cb ,lead ,pb #ajd ,t9 ,sn #ei ,ars5ic ,z #ge ,antimony ,sb #abi ,nobel ,m]cury ,hg #bjb ,metals4 ,silv] ,ag #ajh ,gold ,au #aig ,plat9um ,pt #ii #ee ,! atomic weights1 ) ! exception ( t ( ,gold1 are tak5 f ! la/ edition ( ,br&e's ',manual ( ,*emi/ry4' ,,on ,,! ,,b9>y ,,comp\nds ,,( ,,! ,,elem5ts4 ,_m ( ! elem5t>y bodies exhibit a /rong t5d5cy to comb9e ) ea* o!r1 & to =m comp\nds1 :i* diff] 9 prop]ties f ei!r ( _! con/itu5t elem5ts4 ,?is attraction1 :i* is t]m$ ,*emical ,aff9ity1 is ex]t$ pr9cipally betwe5 bodies :i* are oppos$ to ea* o!r 9 _! g5]al *>act]s4 ,?us1 tak+ = example ! elem5ts ,*lor9e & ,iod9e--!y are analog\s 9 _! reactions1 & !re=e !re is b little attraction betwe5 !m1 :]eas ei!r ( ! two comb9es eag]ly ) ,silv]1 :i* is an elem5t ( a diff]5t class4 ,s1 aga94 ,sulphur unites ) ! metals1 b two metallic elem5ts are comp>atively indiff]5t to ea* o!r4 ,oxyg5 is by f> ! mo/ important 9 ! li/ ( *emical elem5ts4 ,x comb9es ) all ! o!rs1 ) ! s+le exception1 p]haps1 ( ,fluor9e4 ,! attraction1 or *emical aff9ity1 h[ev]1 :i* is ex]t$1 v>ies mu*1 9 diff]5t cases4 ,! metals1 z a class1 are easily oxidiz$2 :il/ _m ( ! non-metallic elem5ts1 su* z ,*lor9e1 ,iod9e1 ,brom9e1 etc41 exhibit b little aff9ity = ,oxyg54 ,nitrog5 is also a peculi>ly negative elem5t1 %[+ little or no t5d5cy to unite ) ! o!rs4 ,classification ( b9>y comp\nds conta9+ ,oxyg54--,:5 "o simple elem5t unites ) ano!r1 ! product is t]m$ a b9>y comp\nd4 ,!re are ?ree di/9ct classes ( b9>y comp\nds ( ,oxyg53--,neutral ,oxides1 basic ,oxides1 & acid ,oxides4 ,neutral & basic ,oxides4--,take z examples--! ,oxide ( ,hydrog51 or ,wat]1 a neutral ,oxide2 ! ,oxide ( ,potassium1 or ,pota%1 a basic ,oxide4 ,wat] is t]m$ a neutral oxide1 because its aff9ities are l[1 & x is comp>atively indiff]5t to o!r bodies4 ,pota% & ,oxide ( ,silv] are examples ( basic oxides2 b !re is a great diff]5ce betwe5 ! two 9 *emical en]gy1 ! =m] belong+ to a sup]ior class ( bases1 viz4 ! alkal9e4 ,by /udy+ ! prop]ties ( an alkali 7su* z ,pota% or ,soda7 :i* are famili> to all1 we ga9 a correct notion ( ! :ole class ( basic oxides4 ,an alkali is a sub/ance readily soluble 9 wat]1 & yield+ a solution :i* has a slimy feel f its solv5t action ^u ! sk94 ,x imm$iately re/ores ! blue col\r ( r$d5$ litmus1 & *anges ! blue infusion ( cabbage to gre54 ,la/ly1 x is neutraliz$ & loses all its *>act]i/ic prop]ties ^u ! addition ( an acid4 ,! weak] bases are1 z a rule1 sp>+ly or n at all soluble 9 wat]1 nei!r h !y ! same cau/ic & solv5t action ^u ! sk92 b !y re/ore ! col\r ( r$d5$ litmus1 & neutralize acids 9 ! same mann] z ! m p[]ful bases1 or alkalies4 ,! ,acid ,oxides4--,?is class1 tak+ ! /rong] acids z ! type1 may be describ$ z foll[s3--v soluble 9 wat]1 ! solution possess+ an int5sely s\r ta/e1 & a corrod+ r ?an a solv5t action ^u ! sk92 *anges ! blue col\r ( litmus & o!r vegetable sub/ances to r$1 & neutralizes ! alkalies & basic oxides g5]ally4 ,obs]ve h[ev] t ^! prop]ties are possess$ 9 v v>i\s degrees by diff]5t acids4 ,prussic ,acid & ,c>bonic ,acid1 = in/ance1 are n s\r to ! ta/e1 & be+ feeble 9 _! reactions1 r$d5 litmus sc>cely or n at all4 ,all acids h[ev]1 )\t any exception1 t5d to comb9e ) bases & to neutralize !mselves2 s t ?is may be said to be ! mo/ *>act]i/ic prop]ty ( ! class4 ,*emical composition ( ,acid & ,basic ,oxides contra/$4--,x is a law commonly obs]v$1 al?\gh ) _m exceptions1 t bases are =m$ by ! union ( ,oxyg5 ) metals2 & acids1 by ,oxyg5 unit+ ) non-metallic elem5ts4 ,?us1 ,sulphuric ,acid is a comp\nd ( ,sulphur & ,oxyg52 ,nitric ,acid1 ( ,nitrog5 & ,oxyg54 ,b ! alkali1 ,pota%1 is an oxide ( ! metal ,potassium2 & ! oxides ( ,iron1 ,silv]1 ,z9c1 etc4 are bases1 & n acids4 ,aga91 ! composition ( acids & bases is diff]5t 9 ano!r respect2 ! =m] inv>iably conta9 m ,oxyg5 9 proportion to ! o!r elem5t ?an ! latt]4 ,tak+ ! same examples z be=e1 ! two classes may be repres5t$ ?us3-- ,acids ,oil ( ,vitriol1 ,sulphur #a atom1 ,oxyg5 #c atoms4 ,aqua-=tis1 ,nitrog5 #a ,oxyg5 #e ,bases ,oxide ( ,silv]1 ,silv] #a atom4 ,oxyg5 #a atom4 ,oxide ( ,iron1 ,iron #a ,oxyg5 #a ,! class ( ,hydrog5 ,acids4--,oxyg5 is s ess5tially ! elem5t :i* =ms ! acidify+ pr9ciple ( acids1 t its v "n is d]iv$ f t fact 71 acid1 & 1 to g5]ate74 ,/ill !re are exceptions to ?is rule1 & 9 "s acids ,hydrog5 appe>s to play ! same "p2 ! ,hydracids1 z !y are t]m$1 are =m$ pr9cipally by ,hydrog5 unit+ ) elem5ts l ,*lor9e1 ,brom9e1 ,iod9e1 ,fluor9e1 etc4 ,?us1 ,muriatic or ,hydro*loric ,acid conta9s ,*lor9e & ,hydrog52 ,hydriodic ,acid conta9s ,iod9e & ,hydrog54 ,obs]ve1 h[ev]1 t ! position held by ! ,hydrog5 9 ^! comp\nds1 is diff]5t f t ( ! ,oxyg5 9 ! ,oxyacids1 z reg>ds ! numb] ( atoms usually pres5t2 ?us-- ,aqua-=tis ,nitrog5 #a atom1 ,oxyg5 #e atoms1 ,muriatic ,acid ,*lor9e #a ,hydrog5 #a atom2 s t ! composition ( ! ,hydracids is analog\s to ! basic oxides1 9 conta9+ a s+le atom ( ea* con/itu5t4 ,,! ,,t]n>y ,,comp\nds ,,( ,,! ,,elem5ts4 ,z ! v>i\s elem5t>y sub/ances unite ) ea* o!r to =m ,b9>y ,comp\nds1 s ^! b9>y comp\nds aga9 unite & =m ,t]n>y ,comp\nds4 ,comp\nd bodies h[ev] d n1 z a rule1 unite ) simple elem5ts4 ,9 illu/ration1 take ! action ( ,nitric ,acid ^u ,silv]1 describ$ at page #ab4 ,no effect is produc$ ^u ! metal until ,oxyg5 is imp>t$2 !n ! ,oxide ( ,silv] s =m$ dissolves 9 ! ,nitric ,acid4 ,9 o!r words1 x is necess>y t a b9>y comp\nd %\ld be fir/ =m$1 be=e ! solution c take place4 ,! mutual attraction or *emical aff9ity exhibit$ by comp\nd bodies is1 z 9 ! case ( elem5ts1 mo/ /rongly m>k$ :5 ! two sub/ances are oppos$ to ea* o!r 9 _! g5]al prop]ties4 ,?us1 acids d n unite ) o!r acids1 b !y comb9e in/antly ) alkalies2 ! two mutually neutraliz+ ea* o!r & =m+ a salt4 ,salts !re=e are t]n>y comp\nds produc$ by ! union ( acids & bases2 common ,salt1 =m$ by neutraliz+ ,muriatic ,acid ) ,soda1 be+ tak5 z ! type ( ! :ole class4 ,g5]al *>act]s ( ! ,salts4--,an aque\s solution ( ,*loride ( ,sodium1 or common ,salt1 possesses ^? *>act]s :i* are usually t]m$ sal9e2 x is nei!r s\r nor corrosive1 b1 on ! o!r h&1 has a cool+ agreeable ta/e4 ,x produces no effect ^u litmus & o!r vegetable col\rs1 & is want+ 9 ^? en]getic reactions :i* are *>act]i/ic ( bo? acids & alkalies2 h5ce1 al?\gh =m$ by ! union ( two b9>y comp\nds1 x diff]s ess5tially 9 prop]ties f bo?4 ,all salts h[ev] d n correspond to ?is description ( ! prop]ties ( ,*loride ( ,sodium4 ,! ,c>bonate ( ,pota%1 = in/ance1 is an acrid & alkal9e salt1 & ! ,nitrate ( ,iron r$d5s litmus-pap]4 ,a p]fectly neutral salt is =m$ :5 a /rong acid unites ) an en]getic base2 b if1 ( ! two con/itu5ts1 "o is m p[]ful ?an ! o!r1 ! prop]ties ( t "o are (t5 se5 9 ! result+ salt4 ,?us ! ,c>bonate ( ,pota% is alkal9e to te/-pap]1 because ! ,c>bonic ,acid is feeble 9 its reactions2 b if ,nitric ,acid & ,pota% are br\ght toge!r1 !n a ,nitrate ( ,pota% is produc$1 :i* is neutral 9 e s5se ( ! t]m4 ,! ,*loride ( ,sodium & salts ( a simil> k9d are freely soluble 9 wat]1 b all salts are n s4 ,"s dissolve only sp>+ly1 & o!rs n at all4 ,! ,*loride & ,iodide ( ,silv] are examples ( ! latt] class2 !y are n bitt] & cau/ic l ! ,nitrate ( ,silv]1 b are p]fectly ta/eless f be+ insoluble 9 ! fluids ( ! m\?4 ,x is se5 !re=e f ^! examples1 & _m o!rs :i* might be adduc$1 t ! popul> notion ( a sal9e body is f> f be+ correct1 & t1 9 ! language ( /rict def9ition1 any sub/ance is a salt :i* is produc$ by ! union ( an acid ) an alkali1 indep5d5t ( ! prop]ties x may possess4 ,?us1 ,cyanide ( ,potassium is a true salt1 al?\gh highly poison\s2 ,nitrate ( ,silv] is a salt2 ! gre5 ,sulphate ( ,iron is a salt2 s also is ,*alk or ,c>bonate ( ,lime1 :i* has nei!r ta/e1 col\r1 nor smell4 ,on ! ,hydracid class ( ,salts4--,! di/9ction betwe5 ,oxyacids & ,hydracids has already be5 po9t$ out 7p4 #cji71 ! latt] hav+ be5 %[n to consi/ ( ,hydrog5 unit$ ) elem5ts analog\s 9 _! reactions to ,*lor9e1 ,iod9e1 ,brom9e1 etc4 ,9 a salt =m$ by an ,oxyg5 ,acid1 bo? ! basic & acid elem5ts appe>4 ,?us ! common ,nitre1 :i* is a ,nitrate ( ,pota%1 is f\nd by analysis to conta9 ,oxide ( ,potassium z a base1 9 a /ate ( comb9ation ) ,nitric ,acid4 ,b if a salt be =m$ by neutraliz+ an alkali ) a ,hydrog5 ,acid1 ! product 9 t case does n conta9 all ! elem5ts4 ,?is is se5 f ! foll[+ example3-- ,hydro*loric ,acid ,soda ,*loride ( ,sodium ,wat]2 or1 /at$ m at l5g?1-- 7,*lor9e ,hydrog57 7,oxyg5 ,sodium7 7,*lor9e ,sodium7 7,oxyg5 ,hydrog574 ,obs]ve t ! ,hydrog5 & ,oxyg51 be+ pres5t 9 ! correct proportions1 unite to =m ,wat]1 :i* is an ,oxide ( ,hydrog54 ,?is wat] passes (f :5 ! solution is evaporat$1 & leaves ! dry cry/als ( salt4 ,on ! o!r h&1 ) ! ,oxyacid ,salts1 ! elem5t>y ,hydrog5 be+ abs5t1 no wat] is =m$1 & ! ,oxyg5 rema9s4 ,x mu/ !re=e be borne 9 m9d t salts l ! ,*lorides1 ,bromides1 ,iodides1 etc4 conta9 only two elem5ts2 b t 9 ! ,oxyacid ,salts1 su* z ,sulphates1 ,nitrates1 ,acetates1 ?ree are pres5t4 ,?us1 ,nitrate ( ,silv] consi/s ( ,nitrog51 ,oxyg51 & ,silv]1 b ,*loride ( ,silv] conta9s simply ,*lor9e & metallic ,silv] unit$1 )\t ,oxyg54 ,! ,hydracid salts h[ev]1 :5 decompos$1 yield products simil> to ! ,oxyacid salts4 ,= in/ance1 if ,iodide ( ,potassium be dissolv$ 9 wat]1 & dilute ,sulphuric ,acid add$1 ?is acid1 be+ p[]ful 9 its *emical aff9ities1 t5ds to appropriate to itself ! alkali2 b x does n remove ,potassium & lib]ate ,iod9e1 b takes ! ,oxide ( ,potassium & sets free ,hydriodic ,acid1 ,9 o!r words1 z an atom ( wat] is produc$ dur+ ! =mation ( a ,hydracid ,salt1 s is an atom de/roy$ & made to yield up its elem5ts 9 ! decomposition ( a ,hydracid ,salt4 ,! reaction ( dilute ,sulphuric ,acid ^u ,iodide ( ,potassium may be /at$ ?us3-- ,sulphuric ,acid plus 7,iod9e ,potassium7 plus 7,hydrog5 ,oxyg57 equals 7,sulphuric ,acid1 ,oxyg5 ,potassium7 or ,sulphate ( ,pota%1 & 7,hydrog5 ,iod9e7 or ,hydriodic ,acid4 ,,! ,,nature ,,( ,,*emical ,,aff9ity ,,fur!r ,,illu/rat$4 ,illu/ration f ! ,non-metallic ,elem5ts4--,if a /ream ( ,*lor9e gas be pass$ into a solution conta9+ ! same salt z be=e m5tion$1 viz4 ! ,iodide ( ,potassium1 ! result is to lib]ate a c]ta9 portion ( ,iod9e1 :i* dissolves 9 ! liquid1 & t+es x ( a br[n col\r4 ,! elem5t ,*lor9e1 possess+ a degree ( *emical en]gy sup]ior to t ( ,iod9e1 prevails ov] x1 & removes ! ,potassium ) :i* ! ,iod9e 0 previ\sly comb9$4 ,*lor9e ,iodide ( ,potassium ,iod9e ,*loride ( ,potassium4 ,! same ,law illu/rat$ by ! ,metals4--,a /rip ( ,iron dipp$ 9 solution ( ,nitrate ( ,silv] becomes imm$iately coat$ ) metallic ,silv]2 b a piece ( ,silv]-foil may be left = any l5g? ( "t 9 ,sulphate ( ,iron )\t und]go+ *ange3 ! diff]5ce dep5ds ^u ! fact1 t metallic ,iron has a great] attraction = ,oxyg5 ?an ,silv]1 & h5ce x displaces x f its solution4 ,iron ,nitrate ( ,silv] ,silv] ,nitrate ( ,iron4 ,illu/rations among/ ,b9>y ,comp\nds4--,if a few drops ( solution ( ,pota% be add$ to solution ( ,nitrate ( ,silv]1 a br[n deposit is =m$1 :i* is ! ,oxide ( ,silv]1 sp>+ly soluble 9 wat]4 ,t is to say1 z a /rong] metal displaces metallic ,silv]1 s does an oxide ( ! same metal displace ,oxide ( ,silv]4 ,!re=e bases l ! alkalies1 alkal9e e>?s1 etc4 _c exi/ 9 a free /ate 9 solutions ( ! salts ( weak] bases1--a liquid conta9+ ,nitrate ( ,silv] c\ld n also conta9 free ,pota% or ,ammonia4 ,9 ! li/ giv5 at page #cjf1 ! metallic elem5ts are arrang$ pr9cipally 9 ! ord] ( _! *emical aff9ities2 ^? ( ,potassium1 ,sodium1 ,b>ium1 etc4 be+ ! mo/ m>k$4 ,z ! alkalies displace ! weak] bases f _! comb9ation ) acids1 s ! /rong acids displace weak acids f _! comb9ation ) bases4 ,?us1 z ,oxide ( ,potassium ,acetate ( ,silv] ,oxide ( ,silv] ,acetate ( ,pota%2 ,s ,nitric ,acid ,acetate ( ,silv] ,acetic ,acid ,nitrate ( ,silv]4 ,9 ! li/ ( acids4 ,sulphuric ,acid is usually plac$ fir/ z be+ ! /ronge/1 & ,c>bonic ,acid1 :i* is a gase\s sub/ance1 la/4 ,! vegetable acids1 su* z ,acetic1 ,t>t>ic1 etc41 are int]m$iate1 be+ weak] ?an ! m9]al acids1 b /rong] ?an ,c>bonic1 or ,hydrocyanic ,acid4 ,! ord] ( decompositions affect$ by ! insolubility or ! volatility ( ! products :i* may be =m$4--,x might be inf]r$ f rem>ks already made1 t on mix+ sal9e solutions1 a gradual int]*ange ( elem5ts w\ld take place1 until ! /ronge/ acids 7 associat$ ) ! /ronge/ bases1 & vice v]s4 ,!re are _m causes h[ev] :i* int]f]e to prev5t ?is2 "o ( :i* is volatility4--- ,! viol5t eff]vesc5ce :i* takes place on treat+ a ,c>bonate ( any k9d ) an acid is due to ! gase\s nature ( ,c>bonic ,acid & its escape 9 t =m1 :i* greatly facilitates ! decomposition4 ,insolubility is also a cause :i* ex]cises a great influ5ce on ! result :i* w foll[ 9 mix+ solutions4 ,if ! =mation ( an insoluble sub/ance is possible by any int]*ange ( elem5ts1 x w take place4 ,a solution ( ,*loride ( ,sodium add$ to ,nitrate ( ,silv] inv>iably produces ,*loride ( ,silv]2 ! insolubility ( ,*loride ( ,silv] be+ ! cause :i* det]m9es its =mation4 ,s aga91 ,sulphate ( ,lead & ,protonitrate ( ,iron are produc$ by mix+ ,nitrate ( ,lead ) ,sulphate ( ,iron2 b if ,nitrate ( ,pota% be sub/itut$ = ,nitrate ( ,lead1 ! result is unc]ta91 because !re are no elem5ts pres5t :i* c1 by int]*ang+1 =m an insoluble salt2 ,sulphate ( ,pota%1 al?\gh sp>+ly soluble 9 wat]1 n be+ insoluble1 l ! ,sulphate ( ,lead or ! ,sulphate ( ,b>yta4 ,,on ,,*emical ,,nom5clature4 ,! nom5clature ( ! *emical elem5ts is mo/ly indep5d5t ( any rule2 b an attempt has be5 made to obviate ?is 9 ! case ( ^? ( lat] discov]y4 ,?us ! names ( ! newly-f\nd metals usually end 9 um1 z ,potassium1 ,sodium1 ,b>ium1 ,calcium1 etc42 & ^? elem5ts :i* possess analog\s *>act]s h correspond+ t]m9ations assign$ to !m1 z ,*lor9e1 ,brom9e1 ,iod9e1 ,fluor9e1 etc4 ,nom5clature ( ,b9>y ,comp\nds4--,^! are (t5 nam$ by atta*+ ! t]m9ation ide to ! m important elem5t ( ! two2 z1 ! ,oxide ( ,hydrog51 or ,wat]2 ! ,*loride ( ,silv]2 ! ,sulphide ( ,silv]4 ,b9>y comp\nds ( ,sulphur h[ev] are sometimes t]m$ ,sulphurets1 z ! ,sulphuret or ! ,sulphide ( ,silv] indiff]5tly4 ,:5 ! same body comb9es ) ,oxyg51 or ! correspond+ elem5t1 9 m ?an "o proportion1 ! prefix proto is appli$ to t conta9+ ! lea/ ,oxyg52 sesqui to t ) once & a half z mu* z ! proto2 bi or b9 to t ) twice z mu*2 & p] to ! "o conta9+ ! mo/ ,oxyg5 ( all4 ,z examples1 take ! foll[+3--,! ,protoxide ( ,iron2 ! ,sesquioxide ( ,iron3 ! ,proto*loride ( ,m]cury2 ! ,bi*loride ( ,m]cury4 ,9 ^! examples ! ,sesquioxide ( ,iron is also a ,p]oxide1 because no high] simple oxide is kn[n1 & ! ,bi*loride ( ,m]cury is a ,p]*loride = a simil> reason4 ,:5 an inf]ior comp\nd is discov]$1 x is (t5 t]m$ sub2 z ! ,suboxide ( ,silv]1 ! ,sub*loride ( ,silv]4 ,^! bodies conta9 ! lea/ kn[n quantity ( ,oxyg5 & ,*lor9e respectively1 & are h5ce entitl$ to ! prefix proto2 b be+ ( m9or importance1 !y are except$ f ! g5]al rule4 ,! comb9ations ( metallic elem5ts ) ea* o!r are t]m$ alloys2 or if conta9+ ,m]cury1 amalgams4 ,nom5clature ( b9>y ,comp\nds possess+ acid prop]ties4--,^! are nam$ on a diff]5t pr9ciple4 ,! t]m9ation ic is appli$ to "o elem5t4 ,?us1 tak+ z an illu/ration ! liquid kn[n z ,oil ( ,vitriol1 x is truly an ,oxide ( ,sulphur1 b z x possesses /rong acid prop]ties x is t]m$ ,sulphuric ,acid4 ,s ,nitric ,acid is an ,oxide ( ,nitrog52 ,c>bonic ,acid is an ,oxide ( ,c>bon1 etc4 ,:5 !re are two oxides ( ! same elem5t1 bo? possess+ acid prop]ties1 ! mo/ important has ! t]m9ation ic1 & ! o!r ous2 z ,sulphuric ,acid1 ,sulphurous ,acid2 ,nitric ,acid1 ,nitrous ,acid4 ,nom5clature ( ! ,hydracids4--,! ,hydrog5 ,acids are di/+ui%$ f ,oxyacids by reta9+ ! names ( bo? con/itu5ts1 ! t]m9ation ic be+ annex$ z usual4 ,?us1 ,hydro*loric ,acid1 or ! ,*loride ( ,hydrog52 ,hydriodic ,acid1 or ! ,iodide ( ,hydrog54 ,fur!r illu/rations ( ! nom5clature ( ,b9>y ,comp\nds4--,! ,oxides ( ,nitrog51 & also ( ,sulphur1 af=d an int]e/+ illu/ration ( ! pr9ciples ( nom5clature4 ,! =m] are z foll[s3-- ,nitrog54 ,oxyg54 ,protoxide ( ,nitrog5 #a atom4 #a atom4 ,b9oxide ( ,nitrog5 #a #b ,nitr\s ,acid #a #c ,p]oxide ( ,nitrog5 #a #d ,nitric ,acid #a #e ,obs]ve1 t two only out ( ! five possess acid prop]ties1 ! o!rs be+ simple oxides4 ,nitric ,acid is1 /rictly speak+1 ! ,p]oxide1 b z x belongs to ! class ( acids1 t t]m naturally falls to ! comp\nd bel[4 ,! b9>y comp\nds ( ,sulphur ) ,oxyg5 all possess acid prop]ties2 !y may be repres5t$ 79 "p7 z foll[s3-- ,sulphur4 ,oxyg54 ,hyposulphur\s ,acid #b atoms4 #b atoms4 ,sulphur\s ,acid #a #b ,hyposulphuric ,acid #b #e ,sulphuric ,acid #a #c ,9 ?is case ! ,sulphuric & ,sulphur\s ,acids _h become famili>ly kn[n be=e ! o!rs1 int]m$iate 9 composition1 7 discov]$4 ,h5ce1 to avoid ! confusion :i* w\ld result f *ang+ ! nom5clature1 ! new bodies are t]m$ ,hyposulphuric & ,hyposulphur\s 7f 1 "u74 ,nom5clature ( ,salts4--,salts are nam$ accord+ to ! acid !y conta92 ! t]m9ation ic be+ *ang$ into ate1 & ous into ite4 ,?us1 ,sulphuric ,acid =ms ,sulphates2 ,nitric ,acid1 ,nitrates2 b ,sulphurous ,acid =ms ,sulphites1 & ,nitr\s ,acid1 ,nitrites4 ,9 nam+ a salt1 ! base is always plac$ aft] ! acid1 ! t]m oxide be+ omitt$2 ?us4 ,nitrate ( ,oxide ( ,silv] is m %ortly kn[n z ,nitrate ( ,silv]1 ! pres5ce ( ,oxyg5 be+ und]/ood4 ,:5 !re are two oxides ( ! same base1 bo? ( :i* are salifiable1--9 nam+ ! salts1 ! t]m proto is prefix$ to ! acid ( ! salt =m$ by ! l[e/1 & p] to t ( ! high] oxide2 z1 ! ,protosulphate ( ,iron1 or ,sulphate ( ! ,protoxide2 ! ,p]sulphate ( ,iron1 or ,sulphate ( ! ,p]oxide4 ,_m salts conta9 m ?an "o atom ( acid to ea* atom ( base4 ,9 t case1 ! usual prefixes expressive ( quantity are adopt$3 ?us1 ! ,bisulphate ( ,pota% conta9s twice z mu* ,sulphuric ,acid z ! neutral ,sulphate1 etc4 ,on ! o!r h&1 !re are salts 9 :i* ! base is 9 excess ) reg>d to ! acid1 & :i* are usually kn[n z basic salts2 ?us1 ! r$ p[d] :i* deposits f solution ( ,sulphate ( ,iron1 is a basic ,p]sulphate ( ,iron1 or a ,sulphate ( ! ,p]oxide ( ,iron ) m ?an ! normal proportion ( oxide4 ,nom5clature ( ! ,hydracid ,salts4--,! composition ( ^! salts be+ diff]5t f ^? =m$ by ,oxyg5 ,acids1 ! nom5clature v>ies also4 ,?us1 9 neutraliz+ ,hydro*loric ,acid ) ,soda1 ! product =m$ is n kn[n z ,hydro*lorate ( ,soda1 b z ,*loride ( ,sodium2 ?is salt1 & o!rs ( a simil> con/itution1 be+ b9>y1 & n t]n>y1 comp\nds4 ,! salt produc$ by ,hydro*loric ,acid & ,ammonia h[ev] is (t5 call$ ,muriate or ,hydro*lorate ( ,ammonia1 al?\gh m /rictly x %\ld be ! ,*loride ( ,ammonium4 ,,on ,,symbolic ,,notation4 ,! li/ ( symbols employ$ to repres5t ! v>i\s elem5t>y bodies is giv5 at page #cjf4--;,commonly ! initial lett] ( ! ,lat9 "n is us$1 a second or small] lett] be+ add$ :5 two elem5ts correspond 9 _! initials3 ?us ,c /&s = ,c>bon1 ,cl = ,*lor9e1 ,cd = ,cadmium1 & ,cu = ,copp]4 ,! *emical symbol h[ev] does n simply repres5t a p>ticul> elem5t2 x d5otes also a def9ite weight1 or equival5t proportion1 ( t elem5t4 ,?is w be expla9$ m fully 9 ! succe$+ pages1 :5 speak+ ( ! ,laws ( ,comb9ation4 ,=mul ( ,comp\nds4--,9 ! nom5clature ( comp\nds x is usual to place ! ,oxyg5 or analog\s elem5t fir/ 9 ! case ( b9>y comp\nds1 & ! acid be=e ! base 9 ! t]n>y comp\nds1 or salts2 b 9 repres5t+ !m symbolically ?is ord] is rev]s$3 ?us1 ,oxide ( ,silv] is writt5 ,ag,o1 & nev] z ,o,ag2 ,nitrate ( ,silv] z ,ag,o ,,no#e1 n ,,no#e;,ag,o4 ,! juxtaposition ( symbols expresses comb9ation2 ?us1 ,fe,o is a comp\nd ( "o proportion ( ,iron ) "o ( ,oxyg51 or ! ,protoxide ( ,iron1 ,if m ?an "o equival5t be pres5t1 small figures are plac$ bel[ ! symbols3 ?us1 ,fe#b,o#c repres5ts two equival5ts ( ,iron unit$ ) ?ree ( ,oxyg51 or ! ,p]oxide ( ,iron2 ,,s#c1 "o equival5t ( ,sulphur ) ?ree ( ,oxyg51 or ,sulphuric ,acid4 ,l>g] figures plac$ be=e & 9 ! same l9e ) ! symbols1 affect ! :ole comp\nd :i* ! symbols express3 ?us1 #b ,,s#c means two equival5ts ( ,sulphuric ,acid2 #c ,,no#e1 ?ree equival5ts ( ,nitric ,acid4 ,! int]position ( a comma prev5ts ! influ5ce ( ! l>ge figure f ext5d+ fur!r4 ,?us1 ! d\ble ,hyposulphite ( ,soda & ,silv] is repres5t$ z foll[s3-- #b ,na,o ,s#b,o#b1 ,ag,o ,s#b,o#b1 or two equival5ts ( ,hyposulphite ( ,soda ) "o ( ,hyposulphite ( ,silv]2 ! l>ge figure ref]r+ only to ! fir/ half ( ! =mula4 ,sometimes brackets1 etc4 are employ$1 9 ord] to r5d] a complicat$ =mula m pla94 ,= example1 ! =mula = ! d\ble ,hyposulphite ( ,gold & ,soda1 or ,sel d'or1 may be writt5 ?us2-- #c 7,na,o ,s#b,o#b7 ,au,o ,s#b,o#b #d ,,ho4 ,9 ?is =mula1 ! plus sign 77 d5otes t ! f\r atoms ( wat] :i* foll[1 are less intimately unit$ ) ! framework ( ! salt ?an ! o!r con/itu5ts4 ,! use ( a plus sign is commonly adopt$ 9 repres5t+ salts :i* conta9 wat] ( cry/allization4 ,?us1 ! =mula = ! cry/alliz$ ,protosulphate ( ,iron is writt5 z foll[s3-- ,fe,o ,,s#c #g ,,ho4 ,^! atoms ( wat] are driv5 (f by ! application ( heat1 leav+ a :ite sub/ance1 :i* is ! ,anhydr\s salt1 & w\ld be writt5 simply z ,fe,o ,,s#c4 ,! plus sign h[ev] is (t5 employ$ 9 tok5 ( simple addition1 no comb9ation ( any k9d be+ int5d$4 ,?us ! decomposition :i* foll[s on mix+ ,*loride ( ,sodium ) ,nitrate ( ,silv] may be writt5 z foll[s3-- ,na,cl ,ag,o ,,no#e ,ag,cl ,na,o ,,no#e2 t is1-- ,*loride ( ,sodium add$ to ,nitrate ( ,silv]4 ,*loride ( ,silv] & ,nitrate ( ,soda4 ,,on ,,equival5t ,,proportions4 ,:5 elem5t>y or comp\nd bodies ent] into *emical union ) ea* o!r1 !y d n comb9e 9 indef9ite proportions1 z 9 ! case ( a mixture ( two liquids1 or ! solution ( a sal9e body 9 wat]4 ,on ! o!r h&1 a c]ta9 def9ite weight ( ! "o unites ) an equally def9ite weight ( ! o!r2 & if an excess ( ei!r be pres5t1 x rema9s free & uncomb9$4 ,?us1 if we take a s+le gra9 ( ! elem5t ,hydrog5--to conv]t t gra9 into ,wat] !re w be requir$ exactly #h gra9s ( ,oxyg52 & if a l>g] quantity ?an ?is 7 add$1 z = in/ance t5 gra9s1 !n two gra9s w\ld be ov] & above4 ,s1 to =m ,hydro*loric ,acid1 #a gra9 ( ,hydrog5 takes #cf gra9s ( ,*lor9e3--= ! ,hydriodic ,acid1 #a gra9 ( ,hydrog5 unites ) #abf gra9s ( ,iod9e4 ,aga91 if sep>ate portions ( metallic ,silv]1 ( #ajh gra9s ea*1 are weigh$ out1--9 ord] to conv]t !m into ,oxide1 ,*loride1 & ,iodide ( ,silv] respectively1 !re w\ld be requir$ ,oxyg5 #h gra9s4 ,*lor9e #cf ,iod9e #abf ,!re=e x appe>s t #h gra9s ( ,oxyg5 are equival5t to #cf gra9s ( ,*lor9e & to #abf gra9s ( ,iod9e1 see+ t ^! quantities all play ! same "p 9 comb9+2 & s x is ) reg>d to ! o!r elem5ts1--to e "o ( !m a figure c be assign$ :i* repres5ts ! numb] ( p>ts by weight 9 :i* t elem5t unites ) o!rs4 ,^! figures are ! equival5ts or comb9+ proportions1 & !y are d5ot$ by ! symbol ( ! elem5t4 ,a symbol does n /& z a simple repres5tative ( an elem5t1 b z a repres5tative ( "o equival5t ( an elem5t4 ,?us ,o indicates #h p>ts by weight ( ,oxyg52 ,cl "o equival5t1 or #cf p>ts by weight1 ( ,*lor9e2 & s ) ! re/4 ,obs]ve h[ev] t ^! figures1 t]m$ equival5ts1 d n ref] to ! actual numb] ( p>ts by weight1 b only to ! ratio :i* exi/s betwe5 !m3 if ,oxyg5 is #h1 !n ,*lor9e is #cf2 b if we t]m ,oxyg5 #ajj1 z "s h propos$1 !n ,*lor9e w\ld be #ddbfe4 ,9 ! scale ( equival5ts n[ usually adopt$1 ,hydrog51 z be+ ! l[e/ ( all1 is tak5 z unity1 & ! o!rs are relat$ to x4 ,equival5ts ( ,comp\nds4--,! law ( equival5t proportions applies to comp\nds z well z to simple bodies1 ! comb9+ proportion ( a comp\nd be+ always ! sum ( ! equival5ts ( its con/itu5ts4 ,?us ,sulphur is #af1 & ,oxyg5 #h1 !re=e ,sulphuric ,acid1 or ,,s#c1 equals #dj4 ,! equival5t ( ,nitrog5 is #ad1 t ( ,nitric ,acid1 or ,,no#e1 is #ed4 ,! same rule applies ) reg>d to salts4 ,take = in/ance ! ,nitrate ( ,silv]3 x conta9s ,equival5t4 ,nitrog5 #ad #f ,oxyg5 #dh ,silv] #ajh --- ,total ( equival5ts1 or equival5t #agj ( ! ,nitrate ( ,silv] ,practical application ( ! ,laws ( ,comb9ation 4--,! utility ( be+ acqua9t$ ) ! law ( comb9+ proportions is obvi\s :5 _! nature is und]/ood4 ,z bodies bo? unite ) & replace ea* o!r 9 equival5ts1 a simple calculation %[s at once h[ mu* ( ea* elem5t or comp\nd w be requir$ 9 a giv5 reaction4 ,?us1 suppos+ x be desir$ to conv]t #ajj gra9s ( ,nitrate ( ,silv] into ,*loride ( ,silv]1 ! weight ( ,*loride ( ,sodium :i* w be necess>y is d$uc$ ?us3--"o equival5t1 or #agj p>ts1 ( ,nitrate ( ,silv]1 is decompos$ by an equival5t1 or #fj p>ts1 ( ,*loride ( ,sodium4 ,!re=e z #agj 3 #fj 33 #ajj 3 #ceb2 t is1 #ceb gra9s ( ,salt w precipitate1 9 ! /ate ( ,*loride1 ! :ole ( ! ,silv] conta9$ 9 #ajj gra9s ( ,nitrate4 ,s aga91 9 ord] to =m ! ,iodide ( ,silv]1 ! proportions 9 :i* ! two salts %\ld be mix$ is ?us %[n4 ,! equival5t ( ,iodide ( ,potassium is #aff1 & t ( ,nitrate ( ,silv] is #agj4 ,^! numb]s s ne>ly correspond1 t x is common to direct t equal weights ( ! two salts %\ld be tak54 ,"o m illu/ration w suffice4 ,suppos+ x be requir$ to =m #bj gra9s ( ,iodide ( ,silv]--h[ mu* ,iodide ( ,potassium & ,nitrate ( ,silv] mu/ be us$8 ,"o equival5t1 or #aff p>ts1 ( ,iodide ( ,potassium1 w yield an equival5t1 or #bcd p>ts1 ( ,iodide ( ,silv]2 !re=e z #bcd 3 #aff 33 #bj 3 #adb4 ,h5ce1 if #adb gra9s ( ! ,iodide ( ,potassium be dissolv$ 9 wat]1 & an equival5t quantity1 viz4 #ade gra9s1 ( ! ,nitrate ( ,silv] add$1 ! yell[ precipitate1 :5 wa%$ & dri$1 w weigh precisely #bj gra9s4 ,,on ,,! ,,atomic ,,!ory4 ,! atomic !ory1 orig9ally propos$ by ,dalton1 s mu* facilitates ! compreh5sion ( *emical reactions g5]ally1 t x may be useful to give a %ort sket* ( x4 ,x is suppos$ t all matt] is made up ( an inf9ite numb] ( m9ute atoms1 :i* are elem5t>y1 & d n admit ( fur!r division4 ,ea* ( ^! atoms possesses an actual weight1 al?\gh inappreciable by our pres5t me?ods ( inve/igation4 ,simple atoms1 by unit+ ) ea* o!r1 =m comp\nd atoms2 & :5 ^! comp\nds are brok5 up1 ! elem5t>y con/itu5t atoms are n de/roy$1 b sep>ate f ea* o!r1 9 possession ( all _! orig9al prop]ties4 ,9 repres5t+ ! simple atomic /ructure ( bodies1 circles may be us$1 z 9 ! foll[+ diagram4 ,illu/ration3 ,fig4 #a4 ,fig4 #b4 ,fig4 #c4 ,fig4 #a is a comp\nd atom ( ,sulphuric ,acid1 consi/+ ( an atom ( ,sulphur unit$ intimately ) ?ree ( ,oxyg52 fig4 #b is an atom ( ,p]oxide ( ,nitrog51 ,,no#d2 & fig4 #c1 an atom ( ,nitric ,acid1 compos$ ( ,nitrog5 #a atom4 ,oxyg5 #e atoms1 or 9 symbols ,,no#e4 ,! t]m atomic weight sub/itut$ = equival5t proportion4--,if we suppose t ! simple atoms ( diff]5t k9ds ( matt] diff] 9 weight1 & t ?is diff]5ce is express$ by _! equival5t numb]s1 ! :ole laws ( comb9ation foll[ by ! simple/ reason+4 ,x is easy to und]/& t an atom ( "o elem5t1 or comp\nd1 w\ld displace1 or be sub/itut$ =1 a s+le atom ( ano!r2 !re=e1 tak+ z ! illu/ration ! decomposition ( ,iodide ( ,potassium by ,*lor9e1--! weight ( ! latt] elem5t requir$ to lib]ate #abf gra9s ( ,iod9e is #cf gra9s1 because ! weights ( ! atoms ( ^? two elem5t>y bodies are z #cf to #abf4 ,s aga91 9 ! reaction betwe5 ,*loride ( ,sodium & ,nitrate ( ,silv]1 a comp\nd atom ( ! =m]1 repres5t$ by ! weight #fj1 reacts ^u a comp\nd atom ( ! latt]1 :i* equals #agj4 ,!re=e 9 place ( ! t]m equival5t or comb9+ proportion1 x is m usual to employ t ( atomic weight4 ,?us ! atomic weight ( ,oxyg5 is #h1 repres5t$ by ! symbol ,o2 t ( ,sulphur is #af2 h5ce ! atomic weight ( ! comp\nd atom ( ,sulphuric ,acid1 or ,,s#c1 is necess>ily equal to ! comb9$ weights ( ! f\r simple atoms2 id e/1 #af #bd #dj4 ,,on ,,! ,,*emi/ry ,,( ,,organic ,,sub/ances4 ,by organic sub/ances are meant ^? :i* h possess$ life1 ) def9ite organs & tissues1 9 contra-di/9ction to ! v>i\s =ms ( dead inorganic matt]1 9 :i* no /ructural organization ( t k9d is f\nd4 ,! t]m organic h[ev] is also appli$ to sub/ances :i* are obta9$ by *emical processes f ! vegetable & animal k+doms1 al?\gh !y _c !mselves be said to be liv+ bodies2 ?us ,acetic ,acid1 procur$ by ! di/illation ( woody fibre1 & ,alcohol1 by f]m5tation f sug>1 are /rictly organic sub/ances4 ,! class ( organic bodies embraces a great v>iety ( products2 :i*1 l inorganic ,oxides1 may be divid$ into neutral1 acid1 & basic4 ,! organic acids are num]\s1 includ+ ,acetic ,acid1 ,t>t>ic1 ,citric1 & a v>iety ( o!rs4 ,! neutral sub/ances _c easily be assimilat$ to any class ( inorganic comp\nds2 z examples1 take ,/>*1 ,sug>1 ,lign9e1 etc4 ,! bases are also a l>ge class4 ,!y are mo/ly r>e sub/ances1 n famili>ly kn[n3 ,morphia1 obta9$ f ,opium2 ,qu9ia1 f ,qu99e2 ,nicot9e1 f ,tobacco1 are illu/rations4 ,composition ( organic & inorganic bodies contra/$4--,!re are m ?an fifty elem5t>y sub/ances f\nd 9 ! inorganic k+dom1 b only f\r1 commonly speak+1 9 ! organic3 ^! f\r are ,c>bon1 ,hydrog51 ,nitrog51 & ,oxyg54 ,"s organic bodies1--oil ( turp5t9e1 naph?a1 etc41 conta9 only ,c>bon & ,hydrog52 _m o!rs1 su* z sug>1 gum1 alcohol1 fats1 vegetable acids--,c>bon1 ,hydrog51 & ,oxyg54 ,! ,nitrog5\s bodies1 s call$1 conta9+ ,nitrog5 9 addition to ! o!r elem5ts1 are pr9cipally sub/ances d]iv$ f animal & vegetable tissues1 su* z ,album51 ,case9e1 ,gelat9e1 etc42 ,sulphur & ,phosphorus are also pres5t 9 _m ( ! ,nitrog5\s bodies1 b only to a small ext5t4 ,organic sub/ances1 al?\gh simple z reg>ds ! numb] ( elem5ts involv$ 9 _! =mation1 are (t5 highly complex 9 ! arrangem5t ( ! atoms2 ?is may be illu/rat$ by ! foll[+ =mul3-- ,/>* ,c#bd;,h#bj,o#bj ,lign9e ,c#bd;,h#bj,o#bj ,cane ,sug> ,c#bd;,h#bb,o#bb ,grape ,sug> ,c#bd;,h#bh,o#bh ,inorganic bodies1 z already %[n1 unite 9 pairs1--two elem5ts jo9 to =m a b9>y comp\nd2 two b9>y comp\nds produce a salt2 two salts associat$ toge!r =m a d\ble salt4 ,) organic bodies h[ev] ! arrangem5t is diff]5t1--! elem5t>y atoms are all gr\p$ equally 9 "o comp\nd atom1 :i* is highly complex 9 /ructure1 & _c be split up into b9>y products4 ,obs]ve also1 z *>act]i/ic ( ,organic ,*emi/ry1 ! app>5t simil>ity 9 composition betwe5 bodies :i* diff] widely 9 prop]ties4 ,z examples take ,lign9e1 or cotton fibre1 & ,/>*1--ea* ( :i* conta9s ! ?ree elem5ts unit$ z ,c#bd;,h#bj,o#bj4 ,mode ( di/+ui%+ betwe5 ,organic & ,inorganic matt]4--,a simple means ( do+ ?is is z foll[s3-- place ! suspect$ sub/ance ^u a piece ( ,plat9um-foil1 & heat x to r$ness ) a _s-lamp3 if x fir/ black5s1 & !n burns completely away1 x is probably ( organic orig94 ,?is te/ dep5ds ^u ! fact1 t ! con/itu5t elem5ts ( organic bodies are all ei!r !mselves volatile1 or capable ( =m+ volatile comb9ations ) ,oxyg54 ,inorganic sub/ances1 on ! o!r h&1 are (t5 unaffect$ by heat1 or1 if volatile1 are dissipat$ )\t previ\s *>r+4 ,! action ( heat ^u organic matt] may fur!r be illu/rat$ by ! combu/ion ( coal or wood 9 an ord9>y furnace2--fir/1 an escape ( ,c>bon & ,hydrog51 unit$ 9 ! =m ( volatile gase\s matt]1 takes place1 leav+ beh9d a black c9d]1 :i* consi/s ( ,c>bon & inorganic matt] comb9$2 aft]w>ds ?is ,c>bon burns away into ,c>bonic ,acid1 & a grey a% is left :i* is compos$ ( inorganic salts1 & is inde/ructible by heat4 ,,*apt] ,,ii4 ,,vocabul>y ,,( ,,photographic ,,*emicals4 ,,acetic ,,acid4 ,symbol1 ,c#d;,h#c,o#c ,,ho4 ,atomic weight1 #fj4 ,acetic ,acid is a product ( ! oxidation ( ,alcohol4 ,spiritu\s liquids1 :5 p]fectly pure1 are n affect$ by exposure to air2 b if a portion ( yea/1 or ,nitrog5\s organic matt] ( any k9d1 be add$1 x soon acts z a f]m5t1 & causes ! _s to unite ) oxyg5 d]iv$ f ! atmosph]e1 & s to become s\r f =mation ( ,acetic ,acid1 or v9eg>4 ,acetic ,acid is also produc$ on a l>ge scale by heat+ wood 9 close vessels3 a sub/ance di/ils ov] :i* is ,acetic ,acid contam9at$ ) empyreumatic & t>ry matt]2 x is t]m$ ,pyroligne\s ,acid1 & is mu* us$ 9 comm]ce4 ,! mo/ conc5trat$ ,acetic ,acid may be obta9$ by neutraliz+ common v9eg> ) ,c>bonate ( ,soda1 & cry/alliz+ out ! ,acetate ( ,soda s =m$2 ?is ,acetate ( ,soda is !n di/ill$ ) ,sulphuric ,acid1 :i* removes ! ,soda & lib]ates ,acetic ,acid3 ! ,acetic ,acid be+ volatile1 di/ils ov]1 & may be cond5s$4 ,prop]ties ( ,acetic ,acid4--,! /ronge/ acid conta9s only a s+le atom ( wat]2 x is sold "u ! "n ( ,glacial ,acetic ,acid1 s call$ f its prop]ty ( solidify+ at a mod]ately l[ temp]ature4 ,at ab\t #ej ! cry/als melt1 & =m a limpid liquid ( pung5t od\r & a d5sity ne>ly correspond+ to t ( wat]2 ! specific gravity ( ,acetic ,acid h[ev] is no te/ ( its real /r5g?1 :i* c only be e/imat$ by analysis4 ,! comm]cial ,glacial ,acetic ,acid is (t5 dilut$ ) wat]1 :i* may be suspect$ if x does n solidify dur+ ! cold w9t] mon?s4 ,sulphur\s & ,hydro*loric ,acids are also common impurities4 ,!y are injuri\s 9 ,photographic ,processes1 f _! prop]ty ( precipitat+ ,nitrate ( ,silv]4 ,to detect !m proce$ z foll[s3--dissolve a small cry/al ( ,nitrate ( ,silv] 9 a few drops ( wat]1 & add to x ab\t half a dra*m ( ! ,glacial ,acid2 ! mixture %\ld rema9 q cle> ev5 :5 expos$ to ! light4 ,hydro*loric & ,sulphur\s ,acid produce a :ite deposit ( ,*loride or ,sulphite ( ,silv]2 & if ,aldehyde or volatile t>ry matt] be pres5t 9 ! ,acetic ,acid1 ! mixture ) ,nitrate ( ,silv]1 al?\gh cle> at fir/1 becomes discol\r$ by ! action ( light4 ,glacial ,acetic ,acid sometimes has a smell ( g>lic4 ,9 ?is /ate x probably conta9s an organic ,sulphur ,acid1 & is unfit = use4 ,_m employ a *eap] =m ( ,acetic ,acid1 sold by druggi/s z ,beaufoy's acid2 x %\ld be ( ! /r5g? ( ! ,acetic ,acid =tiss4 ( ! ,london ,ph>macopia1 conta9+ #cj p] c5t1 real acid4 ,x w be advisable to te/ x = ,sulphuric ,acid 7see ,sulphuric ,acid71 & o!r impurities1 be=e use4 ,,acetate ,,( ,,silv]4 ,see ,silv]1 ,acetate (4 ,,album54 ,album5 is an organic pr9ciple f\nd bo? 9 ! animal & vegetable k+dom4 ,its prop]ties are be/ /udi$ 9 ! :ite ( egg1 :i* is a v pure =m ( ,album54 ,album5 is capable ( exi/+ 9 two /ates2 9 "o ( :i* x is soluble1 9 ! o!r insoluble1 9 wat]4 ,! aque\s solution ( ! soluble v>iety gives a slightly alkal9e reaction to te/-pap]2 x is some:at ?ick & glut9\s1 b becomes m fluid on ! addition ( a small quantity ( an alkali1 su* z ,pota% or ,ammonia4 ,soluble ,album5 may be conv]t$ into ! insoluble =m 9 ! foll[+ ways3-- #a4 ,by ! application ( heat4--,a mod]ately /rong solution ( ,album5 becomes opalesc5t & coagulates on be+ heat$ to ab\t #aej ,fahr5heit1 b a temp]ature ( #bab is requir$ if ! liquid is v dilute4 ,a lay] ( dri$ ,album5 _c easily be coagulat$ by ! m]e application ( heat4 #b4 ,by addition ( /rong acids4--,nitric ,acid coagulates ,album5 p]fectly )\t ! aid ( heat4 ,acetic ,acid h[ev] acts diff]5tly1 appe>+ to ent] into comb9ation ) ! ,album51 & =m+ a comp\nd soluble 9 w>m wat] acidifi$ by ,acetic ,acid4 #c4 ,by ! action ( metallic salts4--,_m ( ! salts ( ! metals coagulate ,album5 completely4 ,nitrate ( ,silv] does s2 also ! ,bi*loride ( ,m]cury4 ,ammoniacal ,oxide ( ,silv] h[ev] does n coagulate ,album54 ,! :ite precipitate =m$ on mix+ ,album5 ) ,nitrate ( ,silv] is a *emical comp\nd ( ! animal matt] ) ,protoxide ( ,silv]4 ,?is sub/ance1 :i* has be5 t]m$ ,album9ate ( ,silv]1 is soluble 9 ,ammonia & ,hyposulphite ( ,soda2 b aft] exposure to light1 or heat+ 9 a curr5t ( ,hydrog5 gas1 x assumes a brick-r$ col\r1 be+ probably r$uc$ to ! condition ( an organic comp\nd ( a ,suboxide ( ,silv]4 ,x is !n almo/ insoluble 9 ,ammonia1 b en\gh dissolves to t+e ! liquid w9e-r$4 ,! r$ coloration ( solution ( ,nitrate ( ,silv] employ$ 9 s5sitiz+ ! ,album9iz$ photographic pap] is probably produc$ by ! same comp\nd1 al?\gh1 (t5 ref]r$ to ! pres5ce ( ,sulphuret ( ,silv]4 ,album5 also comb9es ) ,lime & ,b>yta4 ,:5 ,*loride ( ,b>ium is us$ ) ,album51 a :ite precipitate ( ?is k9d usually =ms4 ,*emical composition ( ,album54--,album5 belongs to ! ,nitrog5\s class ( organic sub/ances 7see page #cbe74 ,x also conta9s small quantities ( ,sulphur & ,phosphorus4 ,,alcohol4 ,symbol1 ,c#d;,h#f,o#b4 ,atomic weight1 #df4 ,alcohol is obta9$ by ! c>eful di/illation ( any spiritu\s or f]m5t$ liquor4 ,if w9e or be] be plac$ 9 a retort1 & heat appli$1 ! ,alcohol1 be+ m volatile ?an wat]1 rises fir/1 & is cond5s$ 9 an appropriate receiv]2 a portion ( ! vap\r ( wat] h[ev] passes ov] ) ! ,alcohol1 & dilutes x to a c]ta9 ext5t1 =m+ :at is t]m$ ,spirits ( ,w9e4 ,mu* ( ?is wat] may be remov$ by r$i/illation f ,c>bonate ( ,pota%1 9 ! mann] describ$ at page #aif ( ?is "w2 b 9 ord] to r5d] ! ,alcohol ?or\ghly anhydr\s1 x is necess>y to employ ,quicklime1 :i* possesses a /ill great] attraction = wat]4 ,an equal weight ( ?is p[d]$ lime is mix$ ) /rong ,alcohol ( #hbc1 & ! two are di/ill$ toge!r4 ,prop]ties ( ,alcohol4--,pure anhydr\s ,alcohol is a limpid liquid1 ( an agreeable od\r & pung5t ta/e2 sp4 gr4 at #fj1 #gid4 ,x absorbs vap\r ( wat]1 & becomes dilut$ by exposure to damp air2 boils at #agc ,fahr4 ,x has nev] be5 froz54 ,alcohol di/ill$ f ,c>bonate ( ,pota% has a specific gravity ( #hae to #hbc1 & conta9s #ij to #ic p] c5t1 ( real _s4 ,! specific gravity ( ord9>y rectifi$ ,spirits ( ,w9e is usually ab\t #hdj1 & x conta9s #hj to #hc p] c5t1 ( absolute ,alcohol4 ,,ammonia4 ,symbol1 ,,nh#c or ,,nh#d,o4 ,atomic weight1 #ag4 ,! liquid kn[n by ?is "n is an aque\s solution ( ! volatile gas ,ammonia4 ,ammoniacal gas conta9s "o atom ( ,nitrog5 comb9$ ) ?ree ( ,hydrog53 ^! two elem5t>y bodies exhibit no aff9ity = ea* o!r1 b !y c be made to unite "u c]ta9 circum/ances1 & ! result is ,ammonia4 ,prop]ties ( ,ammonia4--,ammoniacal gas is soluble 9 wat] to a l>ge ext5t2 ! solution possess+ ^? prop]ties :i* are t]m$ alkal9e 7see page #cjh74 ,ammonia h[ev] diff]s f ! o!r alkalies 9 "o important p>ticul>--x is volatile3 h5ce ! orig9al col\r ( turm]ic-pap] affect$ by ,ammonia is re/or$ on ! application ( heat4 ,solution ( ,ammonia absorbs ,c>bonic ,acid rapidly f ! air1 & is conv]t$ into ,c>bonate ( ,ammonia2 x %\ld !re=e be pres]v$ 9 /opp]$ bottles4 ,besides ,c>bonate1 comm]cial ,ammonia (t5 conta9s ,*loride ( ,ammonium1 recogniz$ by ! :ite precipitate giv5 by ,nitrate ( ,silv] aft] acidify+ ) pure ,nitric ,acid4 ,! /r5g? ( comm]cial ,ammonia v>ies greatly2 t sold = ph>maceutical purposes "u ! "n ( ,liquor ,ammoni1 conta9s ab\t #aj p] c5t1 ( real ,ammonia4 ,! sp4 gr4 ( aque\s ,ammonia dim9i%es ) ! proportion ( ,ammonia pres5t1 ! ,liquor ,ammoni be+ usually ab\t #icf4 ,ammonia1 al?\gh =m+ a l>ge class ( salts1 appe>s at fir/ sight to contra/ /rongly 9 composition ) ! alkalies prop]1 su* z ,pota% & ,soda4 ,m9]al bases g5]ally are protoxides ( metals1 z already %[n at page #cjh1 b ,ammonia consi/s simply ( ,nitrog5 & ,hydrog5 unit$ )\t ,oxyg54 ,! foll[+ rem>ks may p]haps t5d some:at to elucidate ! difficulty3-- ,!ory ( ,ammonium4--,?is !ory supposes ! exi/5ce ( a sub/ance possess+ ! prop]ties ( a metal1 b diff]+ f metallic bodies g5]ally 9 be+ comp\nd 9 /ructure3 ! =mula assign$ to x is ,,nh#d1 "o atom ( ,nitrog5 unit$ ) f\r ( ,hydrog54 ,?is hypo!tical metal is t]m$ ,ammonium2 & ,ammonia1 associat$ ) an atom ( wat]1 may be view$ z its ,oxide1 = ,,nh#c ,,ho pla9ly equals ,,nh#d,o4 ,?us1 z ,pota% is ! ,oxide ( ,potassium1 s ,ammonia is ! ,oxide ( ,ammonium4 ,! composition ( ! salts ( ,ammonia is on ?is view assimilat$ to ^? ( ! alkalies prop]4 ,?us1 ,sulphate ( ,ammonia is a ,sulphate ( ! ,oxide ( ,ammonium2 ,muriate or ,hydro*lorate ( ,ammonia is a ,*loride ( ,ammonium1 etc4 ,,ammonio-,,nitrate ,,( ,,silv]4 ,see ,silv]1 ,ammonio-,nitrate (4 ,,aqua-,,regia4 ,see ,nitro-,hydro*loric ,acid4 ,,b>yta1 ,,nitrate ,,(4 ,see ,nitrate ( ,b>yta4 ,,bi*loride ,,( ,,m]cury4 ,see ,m]cury1 ,bi*loride (4 ,,brom9e4 ,symbol1 ,br4 ,atomic weight1 #gh4 ,?is elem5t>y sub/ance is obta9$ f ! uncry/allizable residuum ( sea-wat]1 t]m$ bitt]n4 ,x exi/s 9 ! wat] 9 v m9ute proportion1 comb9$ ) ,magnesium 9 ! =m ( a soluble ,bromide ( ,magnesium4 ,prop]ties4--,brom9e is a deep r$di%-br[n liquid ( a disagreeable od\r1 & fum+ /rongly at common temp]atures2 sp>+ly soluble 9 wat] 7#a "p 9 #bc1 ,lwig71 b m abundantly s 9 ,alcohol1 & especially 9 ,e!r4 ,x is v heavy1 hav+ a specific gravity ( #cj4 ,brom9e is closely analog\s to ,*lor9e & ,iod9e 9 its *emical prop]ties4 ,x /&s on ! li/ int]m$iately betwe5 ! two2 its aff9ities be+ /rong] ?an ^? ( ,iod9e1 b weak] ?an ,*lor9e 7see ,*lor9e74 ,x =ms a l>ge class ( salts1 ( :i* ! ,bromides ( ,potassium1 ,cadmium1 & ,silv] are ! mo/ famili> to ,photograph]s4 ,,bromide ,,( ,,potassium4 ,symbol1 ,k,br4 ,atomic weight1 #aah4 ,bromide ( ,potassium is prep>$ by add+ ,brom9e to ,cau/ic ,pota%1 & heat+ ! product1 :i* is a mixture ( ,bromide ( ,potassium & ,bromate ( ,pota%1 to r$ness1 9 ord] to drive (f ! ,oxyg5 f ! latt] salt4 ,x cry/allizes 9 anhydr\s cubes1 l ! ,*loride & ,iodide ( ,potassium2 x is easily soluble 9 wat]1 b m sp>+ly s 9 ,alcohol2 x yields r$ fumes ( ,brom9e :5 act$ ^u by ,sulphuric ,acid4 ,,bromide ,,( ,,silv]4 ,see ,silv]1 ,bromide (4 ,,c>bonate ,,( ,,soda4 ,symbol1 ,na,o ,,co#b #aj ,aq4 ,?is salt 0 =m]ly obta9$ f ! a%es ( seawe$s1 b is n[ m economically manufactur$ on a l>ge scale f common salt4 ,! ,*loride ( ,sodium is fir/ conv]t$ into ,sulphate ( ,soda1 & aft]w>ds ! ,sulphate into ,c>bonate ( ,soda4 ,prop]ties4--,! p]fect cry/als conta9 t5 atoms ( wat]1 :i* are driv5 (f by ! application ( heat1 leav+ a :ite p[d]--! anhydr\s ,c>bonate4 ,common ,wa%+ ,soda is a neutral ,c>bonate1 contam9at$ to a c]ta9 ext5t ) ,*loride ( ,sodium & ,sulphate ( ,soda4 ,! ,c>bonate us$ = eff]vesc+ draughts is ei!r a ,bic>bonate ) #a atom ( wat]1 or a ,sesquic>bonate1 conta9+ ab\t #dj p] c5t1 ( real alkali2 x is !re=e ne>ly d\ble z /rong z ! wa%+ ,c>bonate1 :i* conta9s ab\t #bb p] c5t1 ( ,soda4 ,c>bonate ( ,soda is soluble 9 twice its weight ( wat] at #fj1 ! solution be+ /rongly alkal9e4 ,,c>bonate ,,( ,,pota%4 ,see ,pota%1 ,c>bonate (4 ,,case9e4 ,see ,milk4 ,,*>coal1 ,,animal4 ,animal ,*>coal is obta9$ by heat+ animal sub/ances1 su* z bones1 dri$ blood1 horns1 etc41 to r$ness1 9 close vessels1 until all volatile empyreumatic matt]s h be5 driv5 (f1 & a residue ( ,c>bon rema9s4 ,:5 prep>$ f bones x conta9s a l>ge quantity ( inorganic matt] 9 ! %ape ( ,c>bonate & ,phosphate ( ,lime1 ! =m] ( :i* produces alkal9ity 9 react+ ^u ,nitrate ( ,silv] 7see p4 #hi74 ,animal ,*>coal is fre$ f ^! e>?y salts by repeat$ dige/ion 9 ,hydro*loric ,acid2 b unless v c>efully wa%$ x is apt to reta9 an acid reaction1 & s to lib]ate free ,nitric ,acid :5 add$ to solution ( ,nitrate ( ,silv]4 ,prop]ties4--,animal ,*>coal1 :5 pure1 consi/s1 solely ( ,c>bon1 & burns away 9 ! air )\t leav+ any residue3 x is rem>kable = its prop]ty ( decoloriz+ solutions2 ! organic col\r+ sub/ance be+ sep>at$1 b n actually de/roy$1 z x is by ,*lor9e employ$ z a blea*+ ag5t4 ,?is p[] ( absorb+ col\r+ matt] is n possess$ 9 an equal degree by all v>ieties ( ,*>coal1 b is 9 great measure peculi> to ^? d]iv$ f ! animal k+dom4 ,,*9a ,,clay1 ,,or ,,kaol94 ,?is is prep>$1 by c>eful levigation1 f m\ld]+ granite & o!r dis9tegrat$ felspa?ic rocks4 ,x consi/s ( ! ,silicate ( ,alum9a1--t is1 ( ,silicic ,acid or ,fl9t1 :i* is an ,oxide ( ,silicon1 unit$ ) ! base ,alum9a 7,oxide ( ,alum9um74 ,kaol9 is p]fectly insoluble 9 wat] & acids1 & produces no decomposition 9 solution ( ,nitrate ( ,silv]4 ,x is employ$ by ,photograph]s to decolorize solutions ( ,nitrate ( ,silv] :i* h become br[n f ! action ( ,album5 or o!r organic matt]s4 ,comm]cial ,kaol9 may conta9 *alk1 9 :i* /ate x produces alkal9ity 9 solution ( ,nitrate ( ,silv]4 ,! impurity1 detect$ by its eff]vesc5ce ) acids1 is remov$ by wa%+ ! ,kaol9 9 dilut$ v9eg> & subsequ5tly 9 wat]4 ,,*lor9e4 ,symbol1 ,cl4 ,atomic weight1 #cf4 ,*lor9e is a *emical elem5t f\nd abundantly 9 nature1 comb9$ ) metallic ,sodium 9 ! =m ( ,*loride ( ,sodium1 or ,sea-salt4 ,prep>ation4--,by di/ill+ common ,salt ) ,sulphuric ,acid1 ,sulphate ( ,soda & ,hydro*loric ,acid are =m$4 ,hydro*loric ,acid conta9s ,*lor9e comb9$ ) ,hydrog52 by ! action ( nasc5t ,oxyg5 7see ,oxyg571 ! ,hydrog5 may be remov$ 9 ! =m ( wat]1 & ! ,*lor9e left alone4 ,prop]ties4--,*lor9e is a gre5i%-yell[ gas1 ( a pung5t & suffocat+ od\r2 soluble to a consid]able ext5t 9 wat]1 ! solution possess+ ! od\r & col\r ( ! gas4 ,x is ne>ly #b-a_/b times z heavy z a correspond+ bulk ( atmosph]ic air4 ,*emical prop]ties4--,*lor9e belongs to a small natural gr\p ( elem5ts :i* conta9s also ,brom9e1 ,iod9e1 & ,fluor9e4 ,!y are *>act]iz$ by hav+ a /rong aff9ity = ,hydrog51 & also = ! metals2 b are comp>atively indiff]5t to ,oxyg54 ,_m metallic sub/ances actually und]go combu/ion :5 project$ into an atmosph]e ( ,*lor9e1 ! union betwe5 ! two tak+ place ) extreme viol5ce4 ,! *>act]i/ic blea*+ prop]ties ( ,*lor9e gas are expla9$ 9 ! same mann]3--,hydrog5 is remov$ f ! organic sub/ance1 & 9 t way ! /ructure is brok5 up & ! col\r de/roy$4 ,*lor9e is m p[]ful 9 its aff9ities ?an ei!r ,brom9e or ,iod9e4 ,! salts =m$ by ^! ?ree elem5ts are closely analog\s 9 composition & (t5 9 prop]ties4 ,^? ( ! ,alkalies1 ,alkal9e ,e>?s1 & _m ( ! ,metals1 are soluble 9 wat]2 b ! ,silv] salts are insoluble2 ! ,lead salts sp>+ly s4 ,! comb9ations ( ,*lor9e1 ,brom9e1 ,iod9e1 & ,fluor9e1 ) ,hydrog51 are acids1 & neutralize ,alkalies 9 ! usual1 mann]1 ) =mation ( ,alkal9e ,*loride & wat] 7see page #caa74 ,! te/ by :i* ! pres5ce ( ,*lor9e is detect$1 ei!r free or 9 comb9ation ) bases1 is ,nitrate ( ,silv]2 x gives a :ite curdy precipitate ( ,*loride ( ,silv]1 insoluble 9 ,nitric ,acid1 b soluble 9 ,ammonia4 ,! solution ( ,nitrate ( ,silv] employ$ z ! te/ mu/ n conta9 ,iodide ( ,silv]1 z ?is comp\nd is precipitat$ by dilution4 ,,*loride ,,( ,,ammonium4 ,symbol1 ,,nh#d;,cl4 ,atomic weight1 #ed4 ,?is salt1 also kn[n z ,muriate or ,hydro*lorate ( ,ammonia1 occurs 9 comm]ce 9 ! =m ( col\rless & transluc5t masses1 :i* are procur$ by sublimation1 ! dry salt be+ volatile :5 /rongly heat$4 ,x dissolves 9 an equal weight ( boil+1 or 9 ?ree p>ts ( cold wat]4 ,x conta9s m ,*lor9e 9 proportion to ! weight us$ ?an ,*loride ( ,sodium1 ! atomic weights ( ! two be+ z #ed to #fj4 ,,*loride ,,( ,,b>ium4 ,symbol1 ,ba,cl #b ,,ho4 ,atomic weight1 #abc4 ,b>ium is a metallic elem5t v closely alli$ to ,calcium1 ! elem5t>y basis ( ,lime4 ,! ,*loride ( ,b>ium is commonly employ$ z a te/ = ,sulphuric ,acid1 ) :i* x =ms an insoluble precipitate ( ,sulphate ( ,b>yta4 ,x is also said to affect ! col\r ( ! ,photographic image :5 us$ 9 prep>+ ,positive pap]1 :i* may possibly be due to a *emical comb9ation ( ,b>yta ) ,album52 b x mu/ be rememb]$ t ?is ,*loride1 f its high atomic weight1 conta9s less ,*lor9e ?an ! alkal9e ,*lorides 7see page #abd74 ,prop]ties ( ,*loride ( ,b>ium4--,*loride ( ,b>ium occurs 9 ! =m ( :ite cry/als1 soluble 9 ab\t two p>ts ( wat]1 at common temp]ature4 ,^! cry/als conta9 two atoms ( wat] ( cry/allization1 :i* are expell$ at #bab1 leav+ ! anhydr\s ,*loride4 ,,*loride ,,( ,,gold4 ,see ,gold1 ,*loride (4 ,,*loride ,,( ,,sodium4 ,symbol1 ,na,cl4 ,atomic weight1 #fj4 ,common ,salt exi/s abundantly 9 nature1 bo? 9 ! =m ( solid rock-salt & dissolv$ 9 ! wat]s ( ! ocean4 ,prop]ties ( ! pure ,salt4--,fusible )\t decomposition at l[ r$ness1 b sublimes at high] temp]atures2 ! melt$ salt concretes into a h>d :ite mass on cool+4 ,ne>ly insoluble 9 absolute alcohol1 b dissolves 9 m9ute quantity 9 rectifi$ _s4 ,soluble 9 ?ree p>ts ( wat]1 bo? hot & cold4 ,cry/allizes 9 cubes1 :i* are anhydr\s4 ,impurities ( ,common ,salt4--,table ,salt (t5 conta9s l>ge quantities ( ! ,*lorides ( ,magnesium & ,calcium1 :i*1 be+ deliquesc5t1 produce a dampness by absorption ( atmosph]ic moi/ure3 ,sulphate ( ,soda is also commonly pres5t4 ,! salt may be purifi$ by repeat$ re-cry/allization1 b x is m simple to prep>e ! pure comp\nd directly1 by neutraliz+ ,hydro*loric ,acid ) ,c>bonate ( ,soda4 ,,*loride ,,( ,,silv]4 ,see ,silv]1 ,*loride (4 ,,citric ,,acid4 ,?is acid is f\nd abundantly 9 lemon-juice & 9 lime-juice4 ,x occurs 9 comm]ce 9 ! =m ( l>ge cry/als1 :i* are soluble 9 less ?an _! own weight ( wat] at #fj4 ,comm]cial ,citric ,acid is sometimes mix$ ) ,t>t>ic ,acid4 ,! adult]ation may be discov]$ by mak+ a conc5trat$ solution ( ! acid & add+ ,acetate ( ,pota%2 cry/als ( ,bit>trate ( ,pota% w sep>ate if ,t>t>ic ,acid be pres5t4 ,citric ,acid is tribasic4 ,x =ms ) ,silv] a :ite insoluble salt1 conta9+ #c atoms ( ,oxide ( ,silv] to #a atom ( ,citric ,acid4 ,:5 ! ,citrate ( ,silv] is heat$ 9 a curr5t ( ,hydrog5 gas1 a "p ( ! acid is lib]at$ & ! salt is r$uc$ to a ,citrate ( ,suboxide ( ,silv]2 :i* is ( a r$ col\r4 ,! action ( :ite light 9 r$d5+ ,citrate ( ,silv] is %[n by ! ,au?or to be ( a simil> nature4 ,,cyanide ,,( ,,potassium4 ,symbol1 ,,kc#b,n1 or ,k,cy4 ,atomic weight1 #ff4 ,?is salt is a comp\nd ( ,cyanog5 gas ) ! metal ,potassium4 ,cyanog5 is n an elem5t>y body1 l ,*lor9e or ,iod9e1 b consi/s ( ,c>bon & ,nitrog5 unit$ 9 a peculi> mann]4 ,al?\gh a comp\nd sub/ance1 x reacts 9 ! mann] ( an elem5t1 & is !re=e 7l ,ammonium1 previ\sly describ$7 an exception to ! usual laws ( *emi/ry4 ,_m o!r bodies ( a simil> "* are kn[n4 ,prop]ties ( ,cyanide ( ,potassium4--,^! h be5 suffici5tly describ$ at page #dd1 to :i* ! read] is ref]r$4 ,,e!r4 ,symbol1 ,c#d;,h#e,o4 ,atomic weight1 #cg4 ,e!r is obta9$ by di/ill+ a mixture ( ,sulphuric ,acid & ,alcohol4 ,if ! =mula ( ,alcohol 7,c#d;,h#f,o#b7 be comp>$ ) t ( ,e!r1 x w be se5 to diff] f x 9 ! possession ( an additional atom ( ,hydrog5 & ( ,oxyg53 9 ! reaction ! ,sulphuric ,acid removes ^! elem5ts 9 ! =m ( wat]1 & by s do+ conv]ts "o atom ( ,alcohol into an atom ( ,e!r4 ,! t]m ,sulphuric appli$ to ! comm]cial ,e!r has ref]5ce only to ! mann] ( its =mation4 ,prop]ties ( ,e!r4--,! prop]ties ( ,e!r h be5 describ$ to "s ext5t at pages #he & #aie4 ,! foll[+ p>ticul>s h[ev] may be add$4 ,x is nei!r acid nor alkal9e to te/-pap]4 ,specific gravity1 at #fj1 ab\t #gbj4 ,boils at #ih ,fahr5heit4 ,! vap\r is exce$+ly d5se1 & may be se5 pass+ (f f ! liquid & fall+ to ! gr\nd3 h5ce ! dang] ( p\r+ ,e!r f "o bottle to ano!r if a flame be ne> at h&4 ,e!r does n mix ) wat] 9 all proportions2 if ! two are %ak5 toge!r1 aft] a %ort "t ! =m] rises & floats ^u ! surface4 ,9 ?is way a mixture ( ,e!r & ,alcohol may be purifi$ to "s ext5t1 z 9 ! common process ( wa%+ ,e!r4 ,! wat] employ$ h[ev] always reta9s a c]ta9 portion ( ,e!r 7ab\t a t5? "p ( its bulk71 & acquires a /rong e!real od\r2 wa%$ ,e!r also conta9s wat] 9 small quantity4 ,brom9e & ,iod9e are bo? soluble 9 ,e!r1 & gradually react ^u & decompose x4 ,! /rong alkalies1 su* z ,pota% & ,soda1 also decompose ,e!r slightly aft] a "t1 b n imm$iately4 ,expos$ to air & light4 ,e!r is oxidiz$ & acquires a peculi> od\r 7page #he74 ,e!r dissolves fatty & res9\s sub/ances readily1 b inorganic salts are mo/ly insoluble 9 ?is fluid4 ,h5ce x is t ,iodide ( ,potassium & o!r sub/ances dissolv$ 9 ,alcohol are precipitat$ to a c]ta9 ext5t by ! addition ( ,e!r4 ,,fluoride ,,( ,,potassium4 ,symbol1 ,,kf4 ,atomic weight1 #ei4 ,prep>ation4--,fluoride ( ,potassium is =m$ by saturat+ ,hydr(luoric ,acid ) ,pota%1 & evaporat+ to dryness 9 a plat9um vessel4 ,hydr(luoric ,acid conta9s ,fluor9e comb9$ ) ,hydrog52 x is a p[]fully acid & corrosive liquid1 =m$ by decompos+ ,fluor ,sp>1 :i* is a ,fluoride ( ,calcium1 ) /rong ,sulphuric ,acid2 ! action :i* takes place be+ precisely analog\s to t involv$ 9 ! prep>ation ( ,hydro*loric ,acid4 ,prop]ties4--,a deliquesc5t salt1 occurr+ 9 small & imp]fect cry/als4 ,v soluble 9 wat]3 ! solution act+ ^u glass 9 ! same mann] z ,hydr(luoric ,acid4 ,,=mic ,,acid4 ,symbol1 ,c#b;,,ho#c4 ,atomic weight1 #cg4 ,?is sub/ance 0 orig9ally discov]$ 9 ! r$ ant 7,=mica rufa71 b x is prep>$ on a l>ge scale by di/ill+ ,/>* ) ,b9oxide ( ,manganese & ,sulphuric ,acid4 ,prop]ties4--,! /r5g? ( comm]cial ,=mic ,acid is unc]ta91 b x is always m or less dilute4 ,! /ronge/ acid1 z obta9$ by di/ill+ ,=miate ( ,soda ) ,sulphuric ,acid1 is a fum+ liquid ) a pung5t od\r1 & conta9+ only "o atom ( wat]4 ,x inflames ! sk9 9 ! same mann] z ! /+ ( ! ant4 ,=mic ,acid r$uces ! ,oxides ( ,gold1 ,silv]1 & ,m]cury to ! metallic /ate1 & is itself oxidiz$ into ,c>bonic ,acid4 ,! alkal9e =miates also possess ! same prop]ties4 ,,gallic ,,acid4 ,symbol1 ,c#g;,h#c,o#e ,h#c,o4 ,atomic weight1 #id4 ,! *emi/ry ( ,gallic ,acid is suffici5tly describ$ at page #bg1 to :i* ! read] is ref]r$4 ,,gelat9e4 ,symbol1 ,c#ac;,h#aj,o#e,n#b4 ,atomic weight1 #aef4 ,?is is an organic sub/ance some:at analog\s to ,album51 b diff]+ f x 9 prop]ties4 ,x is obta9$ by subject+ bones1 ho(s1 horns1 calves' feet1 etc41 to ! action ( boil+ wat]4 ,! jelly =m$ on cool+ is t]m$ size1 or1 :5 dri$ & cut into slices1 glue4 ,gelat9e1 z x is sold 9 ! %ops1 is a pure =m ( ,glue4 ,is+lass is gelat9e prep>$1 *iefly 9 ,russia1 f ! air-bladd]s ( c]ta9 species ( /urgeon4 ,prop]ties ( ,gelat9e4--,gelat9e s(t5s & swells up 9 cold wat]1 b does n dissolve until heat$3 ! hot solution1 on cool+1 =ms a tremul\s jelly4 ,"o ounce ( cold wat] w reta9 ab\t ?ree gra9s ( ,is+lass )\t gelat9iz+2 b mu* dep5ds ^u ! temp]ature1 a few degrees greatly affect+ ! result4 ,:5 long boil$ 9 wat]1 & especially 9 pres5ce ( an acid1 su* z ! ,sulphuric1 ,gelat9e und]goes a peculi> modification1 & ! ,solution loses ei!r p>tially or entirely its prop]ty ( solidify+ to a jelly4 ,,glyc]9e4 ,fatty bodies are resolv$ by treatm5t ) an alkali into an ,acid--:i* comb9es ) ! alkali1 =m+ a soap1--& ,glyc]9e1 rema9+ 9 solution4 ,pure ,glyc]9e1 z obta9$ by ,price's pat5t process ( di/illation1 is a viscid liquid ( sp4 gr4 ab\t #abc2 miscible 9 all proportions ) wat] & ,alcohol4 ,x is peculi>ly a neutral sub/ance1 exhibit+ no t5d5cy to comb9e ) acids or bases4 ,x has little or no action ^u ,nitrate ( ,silv] 9 ! d>k1 & r$uces x v sl[ly ev5 :5 expos$ to light4 ,,glycyrrhiz9e4 ,glycyrrhiz9e1 obta9$ f ! fre% root ( ,liquorice1 is a sub/ance int]m$iate 9 prop]ties betwe5 a sug> & a res94 ,sp>+ly soluble 9 wat] b v soluble 9 ,alcohol4 ,x precipitates /rong solution ( ,nitrate ( ,silv] :ite1 b ! deposit becomes r$d5$ by exposure to light4 ,its prep>ation is describ$ 9 ! l>g] works on organic *emi/ry4 ,,gold1 ,,*loride ,,(4 ,symbol1 ,au,cl#c4 ,atomic weight1 #cjc4 ,?is salt is =m$ by dissolv+ pure metallic ,gold 9 ,nitro-hydro*loric ,acid1 & evaporat+ at a g5tle heat4 ,! solution af=ds deliquesc5t cry/als ( a deep orange col\r4 ,*loride ( ,gold1 9 a /ate fit = ,photographic use1 may easily be obta9$ by ! foll[+ process3--,place a half-sov]eign 9 any conv5i5t vessel1 & p\r on x half a dra*m ( ,nitric ,acid mix$ ) two & a half dra*ms ( ,hydro*loric ,acid & ?ree dra*ms ( wat]2 dige/ by a g5tle heat1 b d n boil ! acid1 or mu* ( ! ,*lor9e w be driv5 (f 9 ! =m ( gas4 ,at ! expiration ( a few h\rs add fre% ,aqua-,regia 9 quantity ! same z at fir/1 :i* w probably complete ! solution1 b if n1 repeat ! process a ?ird "t4 ,la/ly1 neutralize ! liquid by add+ ,c>bonate ( ,soda until all eff]vesc5ce ceases1 & a gre5 precipitate =ms2 ?is is ,c>bonate ( ,copp]1 :i* mu/ be all[$ sev]al h\rs to sep>ate ?or\ghly4 ,! ,*loride ( ,gold is ?us fre$ f ,copp] & ,silv]1 ) :i* ! metallic ,gold is alloy$ 9 ! /&>d co9 ( ! realm4 ,! solution s prep>$ w be alkal9e1 & consequ5tly prone to a r$uction ( metallic ,gold3 a slight extra quantity ( ,hydro*loric acid %\ld !re=e be add$1 suffici5t to r$d5 a piece ( imm]s$ litmus-pap]4 ,! weight ( a half-sov]eign is ab\t #fa gra9s1 ( :i* #ef gra9s are pure ,gold4 ,?is is equival5t to #hf gra9s ( ,*loride ( ,gold1 :i* w be ! quantity conta9$ 9 ! solution4 ,! foll[+ process = prep>+ ,*loride ( ,gold is m p]fect ?an ! la/3--,dissolve ! ,gold co9 9 ,aqua-,regia z be=e2 !n boil ) excess ( ,hydro*loric ,acid1 to de/roy ! ,nitric ,acid1--dilute l>gely ) di/ill$ wat]1 & add a filt]$ aque\s solution ( common ,sulphate ( ,iron 7#f p>ts to #a ( ,gold72 collect ! precipitat$ ,gold1 :i* is n[ free f copp]2 r$issolve 9 ,aqua-,regia1 & evaporate to dryness on a wat] ba?4 ,avoid us+ ,ammonia to neutralize ,*loride ( ,gold1 z x w\ld occasion a deposit ( ,fulm9at+ ,gold1 ! prop]ties ( :i* are describ$ 9 ! next page4 ,prop]ties ( ,*loride ( ,gold4--,z sold 9 comm]ce x usually conta9s excess ( ,hydro*loric ,acid1 & is !n ( a bright yell[ col\r2 b :5 neutral & some:at conc5trat$1 x is d>k r$ 7,leo rub] ( ! al*emi/s74 ,x gives no precipitate ) ,c>bonate ( ,soda unless heat be appli$2 ! free ,hydro*loric ,acid pres5t =ms1 ) ! alkali4 ,*loride ( ,sodium1 :i* unites ) ! ,*loride ( ,gold1 & produces a d\ble salt1 ,*loride ( ,gold & ,sodium1 soluble 9 wat]4 ,*loride ( ,gold is decompos$ ) precipitation ( metallic ,gold by ,*>coal1 ,sulphur\s ,acid1 & _m ( ! vegetable acids2 also by ,protosulphate & ,protonitrate ( ,iron4 ,x t+es ! cuticle ( an indelible purple t9t4 ,x is soluble 9 ,alcohol & 9 ,e!r4 ,,gold1 ,,fulm9at+4 ,?is is a yell[i%-br[n sub/ance1 precipitat$ on add+ ,ammonia to a /rong solution ( ,*loride ( ,gold4 ,x may be dri$ c>efully at #bab1 b explodes viol5tly on be+ heat$ sudd5ly to ab\t #bij4 ,friction also causes x to explode :5 dry2 b ! moi/ p[d] may be rubb$ or h&l$ )\t dang]4 ,x is decompos$ by ,sulphurett$ ,hydrog54 ,fulm9at+ ,gold is probably an ,aurate ( ,ammonia1 conta9+ #b atoms ( ,ammonia to #a atom ( ,p]oxide ( ,gold4 ,,gold1 ,,hyposulphite ,,(4 ,symbol1 ,au,o ,s#b,o#b4 ,atomic weight1 #bec4 ,hyposulphite ( ,gold is produc$ by ! reaction ( ,*loride ( ,gold ^u ,hyposulphite ( ,soda 7see page #acc74 ,! salt sold 9 comm]ce z ,sel d'or is a d\ble ,hyposulphite ( ,gold & ,soda1 conta9+ "o atom ( ! =m] salt to ?ree ( ! latt]1 ) f\r atoms ( wat] ( cry/allization4 ,x is =m$ by add+ "o "p ( ,*loride ( ,gold1 9 solution1 to ?ree p>ts ( ,hyposulphite ( ,soda1 & precipitat+ ! result+ salt by ,alcohol3 ! ,*loride ( ,gold mu/ be add$ to ! ,hyposulphite ( ,soda1 & n ! ,soda salt to ! ,gold 7see page #bej74 ,prop]ties4--,hyposulphite ( ,gold is un/able & _c exi/ 9 an isolat$ /ate1 quickly pass+ into ,sulphur1 ,sulphuric ,acid1 & metallic ,gold4 ,:5 comb9$ ) excess ( ,hyposulphite ( ,soda 9 ! =m ( ,sel d'or1 x is m p]man5t4 ,sel d'or occurs cry/alliz$ 9 f9e ne$les1 :i* are v soluble 9 wat]4 ,! comm]cial article is (t5 impure1 conta9+ little else ?an ,hyposulphite ( ,soda1 ) a trace ( ,gold4 ,x may be analyz$ by add+ a few drops ( /rong ,nitric ,acid 7free f ,*lor9e71 dilut+ ) wat]1 & aft]w>ds collect+ & ignit+ ! yell[ p[d]1 :i* is metallic ,gold4 ,,grape ,,sug>4 ,symbol1 ,c#bd;,h#bh,o#bh4 ,atomic weight1 #cif4 ,?is modification ( ,sug>1 (t5 t]m$ ,granul> ,sug>1 or ,glucose1 exi/s abundantly 9 ! juice ( grapes & 9 _m o!r v>ieties ( fruit4 ,x =ms ! sac*>9e concretion f\nd 9 honey1 rais9s1 dri$ figs1 etc4 ,x may be produc$ artificially by ! action ( f]m5t+ pr9ciples & ( dilute m9]al acids1 ^u ,/>*4 ,prop]ties4--,grape ,sug> cry/allizes sl[ly & ) difficulty f a conc5trat$ aque\s solution1 9 small hemisph]ical nodules1 :i* are h>d1 & feel gritty betwe5 ! tee?4 ,x is mu* less sweet to ! ta/e ?an ,cane ,sug>1 & n s soluble 9 wat] 7#a "p dissolves 9 #a-a_/b ( cold wat]74 ,grape ,sug> t5ds to absorb ,oxyg51 & h5ce x possesses ! prop]ty ( decompos+ ! salts ( ! noble metals1 & r$uc+ !m by degrees to ! metallic /ate1 ev5 )\t ! aid ( light4 ,cane ,sug> does n possess ^! prop]ties to an equal ext5t1 & h5ce x is readily di/+ui%$ f ! o!r v>iety4 ,! product ( ! action ( ,grape ,sug> ^u ,nitrate ( ,silv] appe>s to be a v l[ =m ( ,oxide ( ,silv] comb9$ ) organic matt]4 ,,honey4 ,?is sub/ance conta9s two di/9ct k9ds ( ,sug>1 ,grape ,sug>1 & an uncry/allizable sub/ance analog\s to1 or id5tical )1 ! ,treacle f\nd associat$ ) common ,sug> 9 ! cane-juice4 ,! agreeable ta/e ( ,honey probably dep5ds ^u ! latt]1 b its r$uc+ p[] on metallic oxides is due to ! =m]4 ,pure ,grape ,sug> c readily be obta9$ f inspissat$ ,honey1 by treat+ x ) ,alcohol1 :i* dissolves out ! syrup1 b leaves ! cry/all9e portion4 ,mu* ( ! comm]cial article is adult]at$1 &1 = ,photographic use1 ! ,virg9 ,honey %\ld be obta9$ direct f ! comb4 ,,hydro*loric ,,acid4 ,symbol1 ,h,cl4 ,atomic weight1 #cg4 ,hydro*loric ,acid is a volatile gas1 :i* may be lib]at$ f mo/ ( ! salts t]m$ ,*lorides by ! action ( ,sulphuric ,acid4 ,! acid1 by its sup]ior aff9ities1 removes ! base2 ?us1-- ,na,cl ,,ho ,,s#c ,na,o ,,s#c ,h,cl4 ,prop]ties4--,abundantly soluble 9 wat]1 =m+ ! liquid ,hydro*loric or ,muriatic ,acid ( comm]ce4 ,! mo/ conc5trat$ solution ( ,hydro*loric ,acid has a sp4 gr4 #ab1 & conta9s ab\t #dj p] c5t1 ( gas2 t commonly sold is some:at weak]1 sp4 gr4 #aad #bh p] c5t1 real acid4 ,pure ,hydro*loric ,acid is col\rless1 & fumes 9 ! air4 ,! yell[ col\r ( ! comm]cial acid dep5ds ^u ! pres5ce ( traces ( ,p]*loride ( ,iron1 or ( organic matt]2 comm]cial ,muriatic ,acid also (t5 conta9s a portion ( free ,*lor9e & ( ,sulphuric ,acid4 ,,hydriodic ,,acid4 ,symbol1 ,,hi4 ,atomic weight1 #abg4 ,?is is a gase\s comp\nd ( ,hydrog5 & ,iod9e1 correspond+ 9 composition to ! ,hydro*loric ,acid4 ,x _c h[ev]1 f its in/ability1 be obta9$ 9 ! same mann]1 s9ce1 on di/ill+ an ,iodide ) ,sulphuric ,acid1 ! ,hydriodic ,acid fir/ =m$ is subsequ5tly decompos$ into ,iod9e & ,hydrog54 ,an aque\s solution ( ,hydriodic ,acid is easily prep>$ by add+ ,iod9e to wat] conta9+ ,sulphurett$ ,hydrog5 gas2 a decomposition takes place1 & ,sulphur is set free3 ?us1 ,,hs ,i ,,hi s4 ,prop]ties4--,hydriodic ,acid is v soluble 9 wat]1 yield+ a /rongly acid liquid4 ,! solution1 col\rless at fir/1 soon becomes br[n f decomposition1 & lib]ation ( free ,iod9e4 ,x may be re/or$ to its orig9al condition by add+ solution ( ,sulphurett$ ,hydrog54 ,,hydrosulphuric ,,acid4 ,symbol1 ,,hs4 ,atomic weight1 #ag4 ,?is sub/ance1 also kn[n z ,sulphurett$ ,hydrog51 is a gase\s comp\nd ( ,sulphur & ,hydrog51 analog\s 9 composition to ! ,hydro*loric & ,hydriodic ,acid4 ,x is usually prep>$ by ! action ( dilute ,sulphuric ,acid ^u ,sulphuret ( ,iron1 z describ$ at page #cgc2 ! decomposition be+ simil> to t involv$ 9 ! prep>ation ( ! ,hydrog5 acids g5]ally3-- ,fe,s ,,ho ,,s#c ,fe,o ,,s#c ,,hs4 ,prop]ties4--,cold wat] absorbs ?ree times its bulk ( ,hydrosulphuric ,acid1 & acquires ! peculi> putrid od\r & poison\s qualities ( ! gas4 ,! solution is fa9tly acid to te/-pap]1 & becomes opalesc5t on keep+1 f gradual sep>ation ( ,sulphur4 ,x is decompos$ by ,nitric ,acid1 & also by ,*lor9e & ,iod9e4 ,x precipitates ,silv] f its solutions 9 ! =m ( black ,sulphuret ( ,silv]2 also ,copp]1 ,m]cury1 ,lead1 etc42 b ,iron & o!r metals ( t class are n affect$1 if ! liquid conta9s free acid4 ,hydrosulphuric ,acid is con/antly employ$ 9 ! *emical laboratory = ^! & o!r purposes4 ,,hydrosulphate ,,( ,,ammonia4 ,symbol1 ,,nh#d,s ,,hs4 ,atomic weight1 #ea4 ,! liquid kn[n by ?is "n1 & =m$ on pass+ ,sulphurett$ ,hydrog5 gas into ,ammonia1 is a d\ble ,sulphuret ( ,hydrog5 & ,ammonium4 ,9 ! prep>ation1 ! passage ( ! gas is to be cont9u$ until ! solution gives no precipitate ) ,sulphate ( ,magnesia1 & smells /rongly ( ,hydrosulphuric ,acid4 ,prop]ties4--,col\rless at fir/1 b aft]w>ds *anges to yell[1 f lib]ation & subsequ5t solution ( ,sulphur4 ,becomes milky on ! addition ( any acid4 ,precipitates1 9 ! =m ( ,sulphuret1 all ! metals :i* are affect$ by ,sulphurett$ ,hydrog51 &1 9 addition1 ^? ( ! class to :i* ,iron1 ,z9c1 & ,manganese belong4 ,hydrosulphate ( ,ammonia is employ$ 9 ,photography to d>k5 ! ,negative image1 & also 9 ! prep>ation ( ,iodide ( ,ammonium1 ! sep>ation ( ,silv] f ,hyposulphite solutions1 etc4 ,,hyposulphite ,,( ,,soda4 ,symbol1 ,na,o ,s#b,o#b #e ,,ho4 ,atomic weight1 #abe4 ,! *emi/ry ( ,hyposulphur\s ,acid & ! ,hyposulphite ( ,soda has be5 suffici5tly describ$ at pages #dc1 #abi1 & #acg ( ! pres5t ,"w4 ,! cry/alliz$ salt includes five atoms ( wat] ( cry/allization4 ,,hyposulphite ,,( ,,gold4 ,see ,gold1 ,hyposulphite (4 ,,hyposulphite ,,( ,,silv]4 ,see ,silv]1 ,hyposulphite (4 ,,icel& ,,moss4 ,cetr>ia ,isl&ica4--,a species ( ,li*5 f\nd 9 ,icel& & ! m\nta9\s p>ts ( ,europe2 :5 boil$ 9 wat]1 x fir/ swells up1 & !n yields a sub/ance :i* gelat9izes on cool+4 ,x conta9s ,li*5 ,/>*1 a bitt] pr9ciple soluble 9 ,alcohol1 t]m$ ,cetr>9e1 & common ,/>*2 traces ( ,gallic ,acid & ,bit>trate ( ,pota% are also pres5t4 ,,iod9e4 ,symbol1 ,i4 ,atomic weight1 #abf4 ,iod9e is *iefly prep>$ at ,glasg[1 f kelp1 :i* is ! fus$ a% obta9$ on burn+ seawe$s4 ,! wat]s ( ! ocean conta9 m9ute quantities ( ! ,iodides ( ,sodium & ,magnesium1 :i* are sep>at$ & /or$ up by ! gr[+ tissues ( ! m>9e plant4 ,9 ! prep>ation1 ! "m-liquor ( kelp is evaporat$ to dryness & di/ill$ ) ,sulphuric ,acid2 ! ,hydriodic ,acid fir/ lib]at$ is decompos$ by ! high temp]ature1 & fumes ( ,iod9e cond5se 9 ! =m ( opaque cry/als4 ,prop]ties4--,iod9e has a blui%-black col\r & metallic lu/re2 x /a9s ! sk9 yell[1 & has a pung5t smell1 l dilut$ ,*lor9e4 ,x is extremely volatile :5 moi/1 boils at #cej1 & produces d5se violet-col\r$ fumes1 :i* cond5se 9 brilliant plates4 ,specific gravity #didf4 ,iod9e is v sp>+ly soluble 9 wat]1 #a "p requir+ #gjjj p>ts = p]fect solution2 ev5 ?is m9ute quantity h[ev] t+es ! liquid ( a br[n col\r4 ,alcohol & ,e!r dissolve x m abundantly1 =m+ d>k-br[n solutions4 ,iod9e also dissolves freely 9 solutions ( ! alkal9e ,iodides1 su* z ! ,iodide ( ,potassium1 ( ,sodium1 & ( ,ammonium4 ,*emical ,prop]ties4--,iod9e belongs to ! ,*lor9e gr\p ( elem5ts1 *>act]iz$ by =m+ acids ) ,hydrog51 & comb9+ ext5sively ) ! metals 7see ,*lor9e74 ,!y are h[ev] comp>atively indiff]5t to ,oxyg51 & also to ea* o!r4 ,! ,iodides ( ! alkalies & alkal9e e>?s are soluble 9 wat]2 also ^? ( ,iron1 ,z9c1 ,cadmium1 etc4 ,! ,iodides ( ,lead1 ,silv]1 & ,m]cury are ne>ly or q insoluble4 ,iod9e possesses ! prop]ty ( =m+ a comp\nd ( a deep blue col\r ) ,/>*4 ,9 us+ ?is z a te/1 x is necess>y fir/ to lib]ate ! ,iod9e 7if 9 comb9ation7 by means ( ,*lor9e1 or ,nitric ,acids saturat$ ) ,p]oxide ( ,nitrog54 ,! pres5ce ( ,alcohol or ,e!r int]f]es to a c]ta9 ext5t ) ! result4 ,,iodide ,,( ,,ammonium4 ,symbol1 ,,nh#d;,i4 ,atomic weight1 #add4 ,! prep>ation & prop]ties ( ?is salt are describ$ at page #aih1 to :i* ! read] is ref]r$4 ,,iodide ,,( ,,cadmium4 ,symbol1 ,cd,i4 ,atomic weight1 #ahb4 ,see page #aii1 = ! prep>ation & prop]ties ( ?is salt4 ,,iodide ,,( ,,iron4 ,symbol1 ,fe,i4 ,atomic weight1 #aed4 ,iodide ( ,iron is prep>$ by dige/+ an excess ( ,iron fil+s ) solution ( ,iod9e 9 ,alcohol4 ,x is v soluble 9 wat] & ,alcohol1 b ! solution rapidly absorbs ,oxyg5 & deposits ,p]oxide ( ,iron2 h5ce ! importance ( pres]v+ x 9 contact ) metallic ,iron1 ) :i* ! sep>at$ ,iod9e may recomb9e4 ,by v c>eful evaporation1 hydrat$ cry/als ( ,proto-iodide may be obta9$1 b ! composition ( ! solid salt usually sold "u t "n _c be dep5d$ on4 ,! ,p]iodide ( ,iron1 correspond+ to ! ,p]*loride1 has n be5 exam9$1 & x is d\btful if any su* comp\nd exi/s4 ,,iodide ,,( ,,potassium4 ,symbol1 ,,ki4 ,atomic weight1 #aff4 ,?is salt is usually =m$ by dissolv+ ,iod9e 9 solution ( ,pota% until x beg9s to acquire a br[n col\r2 a mixture ( ,iodide ( ,potassium & ,iodate ( ,pota% 7,,ko ,,io#e7 is ?us =m$2 b by evaporation & heat+ to r$ness1 ! latt] salt p>ts ) its ,oxyg51 & is conv]t$ into ,iodide ( ,potassium4 ,prop]ties4--,x =ms cubic & prismatic cry/als1 :i* %\ld be h>d1 & v slightly or n at all deliquesc5t4 ,soluble 9 less ?an an equal weight ( wat] at #f,o2 x is also soluble 9 ,alcohol1 b n 9 ,e!r4 ,! proportion ( ,iodide ( ,potassium conta9$ 9 a saturat$ alcoholic solution1 v>ies ) ! /r5g? ( ! _s3--) common ,spirits ( ,w9e1 sp4 gr4 #hcf1 x w\ld be ab\t #h gra9s to ! dra*m2 ) ,alcohol rectifi$ f ,c>bonate ( ,pota%1 sp4 gr4 #hbc1 #d or #e gra9s2 ) absolute ,alcohol1 #a to #b gra9s4 ,! solution ( ,iodide ( ,potassium is in/antly col\r$ br[n by free ,*lor9e2 also v rapidly by ,p]oxide ( ,nitrog5 7page #hf72 ord9>y acids h[ev] act less quickly1 ,hydriodic ,acid be+ fir/ =m$1 & subsequ5tly decompos+ spontane\sly4 ,! impurities ( comm]cial ,iodide ( ,potassium1 ) ! means to be adopt$ = _! removal1 are fully giv5 at page #aig4 ,,iodide ,,( ,,silv]4 ,see ,silv]1 ,iodide (4 ,,iod(orm4 ,! composition ( ?is sub/ance is analog\s to t ( ,*lor(orm1 ,iod9e be+ sub/itut$ = ,*lor9e4 ,x is obta9$ on boil+ toge!r ,iod9e1 ,c>bonate ( ,pota%1 & ,alcohol4 ,iod(orm occurs 9 yell[ nacr\s cry/als1 :i* h a saffron-l od\r4 ,x is insoluble 9 wat]1 b soluble 9 _s4 ,,iron1 ,,protosulphate ,,(4 ,symbol1 ,fe,o ,,s#c #g ,,ho4 ,atomic weight1 #aci4 ,! prop]ties ( ?is salt1 & ( ! two salifiable ,oxides ( ,iron1 are describ$ at page #bi4 ,x dissolves 9 r m ?an an equal weight ( cold wat]1 or 9 less ( boil+ wat]4 ,aque\s solution ( ,sulphate ( ,iron absorbs ! ,b9oxide ( ,nitrog51 acquir+ a deep olive-br[n col\r3 z ?is gase\s ,b9oxide is itself a r$uc+ ag5t1 ! liquid s =m$ has be5 propos$ z a m en]getic develop] ?an ! ,sulphate ( ,iron alone 7874 ,,iron1 ,,protonitrate ,,(4 ,symbol1 ,fe,o ,,no#c #g ,,ho4 ,atomic weight1 #aec4 ,?is salt1 by c>eful evaporation 9 vacuo ov] ,sulphuric ,acid1 =ms transp>5t cry/als1 ( a light gre5 col\r1 & conta9+ #g atoms ( wat]1 l ! ,protosulphate4 ,x is exce$+ly un/able1 & soon becomes r$ f decomposition1 unless pres]v$ f contact ) air4 ,! prep>ation ( solution ( ,protonitrate ( ,iron = develop+ ,collodion ,positives1 is giv5 at page #bjf4 ,,iron1 ,,p]*loride ,,(4 ,symbol1 ,fe#b;,cl#c4 ,atomic weight1 #afd4 ,!re are two ,*lorides ( ,iron1 correspond+ 9 composition to ! ,protoxide & ! ,sesquioxide respectively4 ,! ,proto*loride is v soluble 9 wat]1 =m+ a gre5 solution1 :i* precipitates a dirty :ite ,protoxide on ! addition ( an alkali4 ,! ,p]*loride1 on ! o!r h&1 is d>k br[n1 & gives a foxy-r$ precipitate ) alkalies4 ,prop]ties4--,p]*loride ( ,iron may be obta9$ 9 ! solid =m by heat+ ,iron wire 9 excess ( ,*lor9e2 x cond5ses 9 ! %ape ( brilliant & iridesc5t br[n cry/als1 :i* are volatile1 & dissolve 9 wat]1 ! solution be+ acid to te/-pap]4 ,x is also soluble 9 ,alcohol1 =m+ ! ,t9ctura ,f]ri ,sesqui*loridi ( ! ,ph>macopia4 ,comm]cial ,p]*loride ( ,iron ord9>ily conta9s an excess ( ,hydro*loric ,acid4 ,,litmus4 ,litmus is a vegetable sub/ance prep>$ f v>i\s li*5s1 :i* are pr9cipally collect$ on rocks adjo9+ ! sea4 ,! col\r+ matt] is extract$ by a peculi> process1 & aft]w>ds made up into a pa/e ) *alk1 pla/] ( ,p>is1 etc4 ,litmus occurs 9 comm]ce 9 ! =m ( small cubes ( a f9e violet col\r4 ,9 us+ x = ! prep>ation ( te/-pap]s1 x is dige/$ 9 hot wat]1 & %eets ( por\s pap] are soak$ 9 ! blue liquid s =m$4 ,! r$ pap]s are prep>$ at fir/ 9 ! same mann]1 b aft]w>ds plac$ 9 wat] :i* has be5 r5d]$ fa9tly acid ) ,sulphuric or ,hydro*loric ,acid4 ,,m]cury1 ,,bi*loride ,,(4 ,symbol1 ,hg,cl#b4 ,atomic weight1 #bgd4 ,?is salt1 also call$ ,corrosive ,sublimate1 & sometimes ,*loride ( ,m]cury 7! atomic weight ( ,m]cury be+ halv$71 may be =m$ by heat+ ,m]cury 9 excess ( ,*lor9e1 or m economically1 by sublim+ a mixture ( ,p]sulphate ( ,m]cury & ,*loride ( ,sodium4 ,prop]ties4--,a v corrosive & poison\s salt1 usually sold 9 semi-transp>5t1 cry/all9e masses1 or 9 ! /ate ( p[d]4 ,soluble 9 #af p>ts ( cold1 & 9 #c ( hot wat]2 m abundantly s 9 ,alcohol1 & also 9 ,e!r4 ,! solubility 9 wat] may be increas$ by ! addition ( free ,hydro*loric ,acid1 or ( ,*loride ( ,ammonium4 ,! ,proto*loride ( ,m]cury is an insoluble :ite p[d]1 commonly kn[n "u ! "n ( ,calomel4 ,,me?ylic ,,alcohol4 ,?is liquid1 kn[n also by ! names ( wood naph?a & pyroxylic _s1 is "o ( ! volatile products ( ! de/ructive di/illation ( wood4 ,x is v volatile & limpid1 ) a pung5t od\r4 ,by a rec5t excise regulation1 ord9>y ,_s mix$ ) t5 p] c5t1 ( wood naph?a is sold free ( duty1 "u ! "n ( ,me?ylat$ ,_s4 ,,milk4 ,! ,milk ( h]bivor\s animals conta9s ?ree pr9cipal con/itu5ts--,fatty matt]1 ,case9e1 & ,sug>2 9 addition to ^!1 small quantities ( ! ,*loride ( ,potassium1 & ( ,phosphates ( ,lime & ,magnesia1 are pres5t4 ,! fatty matt] is conta9$ 9 small cells1 & =ms ! great] "p ( ! cream :i* rises to ! surface ( ! milk on /&+2 h5ce %imm$ milk is to be pref]r$ = ,photographic use4 ,! second con/itu5t1 ,case9e1 is an organic pr9ciple some:at analog\s to ,album5 9 composition & prop]ties4 ,its aque\s solution h[ev] does n1 l ,album51 coagulate on boil+1 unless an acid be pres5t1 :i* probably removes a small portion ( alkali ) :i* ! ,case9e 0 previ\sly comb9$4 ,! sub/ance t]m$ r5net1 :i* is ! dri$ /oma* ( ! calf1 possesses ! prop]ty ( coagulat+ ,case9e1 b ! exact mode ( its action is unkn[n4 ,%]ry-w9e is also commonly employ$ to curdle ,milk2 b br&y & o!r spiritu\s liquids1 :5 free f acid & a/r+5t matt]1 h no effect4 ,9 all ^! cases a portion ( ! ,case9e usually rema9s 9 a soluble =m 9 ! :ey2 b :5 ! ,milk is coagulat$ by ! addition ( acids1 ! quantity s left is v small1 & h5ce ! use ( ! r5net is to be pref]r$1 s9ce ! pres5ce ( ,case9e facilitates ! r$uction ( ! s5sitive ,silv] salts4 ,case9e comb9es ) ,oxide ( ,silv] 9 ! same mann] z ,album51 =m+ a :ite coagulum1 :i* becomes brick-r$ on exposure to light4 ,sug> ( ,milk1 ! ?ird pr9cipal con/itu5t1 diff]s f bo? cane & grape sug>2 x may be obta9$ by evaporat+ :ey until cry/allization beg9s to take place4 ,x is h>d & gritty1 & only slightly sweet2 sl[ly soluble1 )\t =m+ a syrup1 9 ab\t two & a half p>ts ( boil+1 & six ( cold wat]4 ,x does n f]m5t & =m ,alcohol on ! addition ( yea/1 l grape sug>1 b by ! action ( decompos+ animal matt] is conv]t$ into ,lactic ,acid4 ,:5 skimm$ ,milk is expos$ to ! air = "s h\rs1 x gradually becomes s\r1 f ,lactic ,acid =m$ 9 ?is way2 & if !n heat$ to ebullition1 ! ,case9e coagulates v p]fectly4 ,,nitric ,,acid4 ,symbol1 ,,no#e4 ,atomic weight1 #ed4 ,nitric ,acid1 or ,aqua-=tis1 is prep>$ by add+ ,sulphuric ,acid to ,nitrate ( ,pota%1 & di/ill+ ! mixture 9 a retort4 ,sulphate ( ,pota% & free ,nitric ,acid are =m$1 ! latt] ( :i*1 be+ volatile1 di/ils ov] 9 comb9ation ) "o atom ( wat] previ\sly unit$ ) ! ,sulphuric ,acid4 ,prop]ties4--,anhydr\s ,nitric ,acid is a solid sub/ance1 :ite & cry/all9e1 b x _c be prep>$ except by an exp5sive & complicat$ process4 ,! conc5trat$ liquid ,nitric ,acid conta9s #a atom ( wat]1 & has a sp4 gr4 ( ab\t #ae2 if p]fectly pure1 x is col\rless1 b usually x has a slight yell[ t9t1 f p>tial decomposition into ,p]oxide ( ,nitrog53 x fumes /rongly 9 ! air4 ,! /r5g? ( comm]cial ,nitric ,acid is subject to mu* v>iation4 ,an acid ( sp4 gr4 #adb1 conta9+ ab\t #d atoms ( wat]1 is commonly met )4 ,if ! specific gravity is mu* l[] ?an ?is 7less ?an #acf71 x w sc>cely be adapt$ = ! prep>ation ( ,pyroxyl9e4 ,! yell[ ,nitr\s ,acid1 s call$1 is a /rong ,nitric ,acid p>tially saturat$ ) ! br[n vap\rs ( ,p]oxide ( ,nitrog52 x has a high specific gravity1 b ?is is some:at deceptive1 be+ caus$ 9 "p by ! pres5ce ( ! ,p]oxide4 ,on mix+ ) ,sulphuric ,acid1 ! col\r disappe>s1 a comp\nd be+ =m$ :i* has be5 t]m$ a ,sulphate ( ,nitr\s ,acid4 ,9 ! ,app5dix a ,table is giv5 :i* exhibits ! quantity ( real anhydr\s ,nitric ,acid conta9$ 9 samples ( diff]5t d5sities4 ,*emical ,prop]ties4--,nitric ,acid is a p[]ful oxidiz+ ag5t 7see page #ac72 x dissolves all ! common metals1 ) ! exception ( ,gold & ,plat9um4 ,animal sub/ances1 su* z ! cuticle1 nails1 etc41 are t+$ ( a p]man5t yell[ col\r1 & deeply corrod$ by a prolong$ application4 ,nitric ,acid =ms a num]\s class ( salts1 all ( :i* are soluble 9 wat]4 ,h5ce its pres5ce _c be det]m9$ by any precipitat+ reag5t1 9 ! same mann] z t ( ,hydro*loric & ,sulphuric ,acid4 ,impurities ( ,comm]cial ,nitric ,acid4--,^! are pr9cipally ,*lor9e & ,sulphuric ,acid2 also ,p]oxide ( ,nitrog51 :i* t+es ! acid yell[1 z already describ$4 ,*lor9e is detect$ by dilut+ ! acid ) an equal bulk ( di/ill$ wat]1 & add+ a few drops ( ,nitrate ( ,silv]1--a milk9ess1 :i*1 is ,*loride ( ,silv] 9 susp5sion1 indicates ! pres5ce ( ,*lor9e4 ,9 te/+ = ,sulphuric ,acid1 dilute ! ,nitric ,acid z be=e1 & drop 9 a s+le drop ( solution ( ,*loride ( ,b>ium2 if ,sulphuric ,acid be pres5t1 an insoluble precipitate ( ,sulphate ( ,b>yta w be =m$4 ,,nitr\s ,,acid4 ,see ,silv]1 ,nitrite (4 ,,nitrate ,,( ,,pota%4 ,symbol1 ,,ko ,,no#e4 ,atomic weight1 #ajb4 ,?is salt1 also t]m$ ,nitre1 or ,saltpetre1 is an abundant natural product1 f\nd effloresc$ ^u ! soil 9 c]ta9 p>ts ( ! ,ea/ ,indies4 ,x is also produc$ artificially 9 :at are call$ ,nitre-b$s4 ,! prop]ties ( ,nitrate ( ,pota% are describ$ z f> z necess>y at page #aij4 ,,nitrate ,,( ,,b>yta4 ,symbol1 ,ba,o ,,no#e4 ,atomic weight1 #aca4 ,nitrate ( ,b>yta =ms octah$ral cry/als1 :i* are anhydr\s4 ,x is consid]ably less soluble ?an ! ,*loride ( ,b>ium1 requir+ #ab p>ts ( cold & #d ( boil+ wat] = solution4 ,x may be sub/itut$ = ! ,nitrate ( ,lead 9 ! prep>ation ( ,protonitrate ( ,iron4 ,,nitrate ,,( ,,lead4 ,symbol1 ,pb,o ,,no#e4 ,atomic weight1 #aff4 ,nitrate ( ,lead is obta9$ by dissolv+ ! metal1 or ! ,oxide ( ,lead1 9 excess ( ,nitric ,acid1 dilut$ ) #b p>ts ( wat]4 ,x cry/allizes on evaporation 9 :ite anhydr\s tetrah$ra & octah$ra1 :i* are h>d1 & decrepitate on be+ heat$2 !y are soluble 9 #h p>ts ( wat] at #fj4 ,nitrate ( ,lead =ms ) ,sulphuric ,acid1 or soluble ,sulphates1 a :ite precipitate1 :i* is ! insoluble ,sulphate ( ,lead4 ,! ,iodide ( ,lead is also v sp>+ly soluble 9 wat]4 ,,nitrate ,,( ,,silv]1 ,see ,silv]1 ,nitrate or4 ,,nitro-,,glucose4 ,:5 #c fluid ounces ( cold ,nitro-,sulphuric ,acid1 consi/+ ( #b ounces ( ,oil ( ,vitriol & #a ounce ( highly conc5trat$ ,nitric ,acid1 are mix$ ) #a ounce ( f9ely p[d]$ ,cane ,sug>1 !re is =m$ at fir/ a ?91 transp>5t1 pa/y mass4 ,if x is /irr$ ) a glass rod = a few m9utes )\t int]ruption1 ! pa/e coagulates z x 71 & sep>ates f ! liquid z a ?ick t5aci\s mass1 aggregat+ into lumps1 :i* c easily be remov$ f ! acid mixture4 ,?is sub/ance has a v acid & int5sely bitt] ta/e4 ,knead$ 9 w>m wat] until ! latt] no long] r$d5s litmus-pap]1 x acquires a silv] col\r & a beautiful silky lu/re4 ,x may be us$ 9 ,photography to conf] int5sity ^u newly mix$ ,collodion2 b is inf]ior to ,glycyrrhiz9e employ$ = ! same purpose4 ,,nitro-,,hydro*loric ,,acid4 ,symbol1 ,,no#d ,cl4 ,?is liquid is ! ,aqua-,regia ( ! old al*emi/s4 ,x is produc$ by mix+ ,nitric & ,hydro*loric ,acids3 ! ,oxyg5 conta9$ 9 ! =m] comb9es ) ! ,hydrog5 ( ! latt]1 =m+ wat] & lib]at+ ,*lor9e1 ?us3-- ,,no#e ,h,cl ,,no#d ,,ho ,cl4 ,! pres5ce ( free ,*lor9e conf]s on ! mixture ! p[] ( dissolv+ ,gold & ,plat9um1 :i* nei!r ( ! two acids possesses sep>ately4 ,9 prep>+ ,aqua-,regia x is usual to mix "o "p1 by measure1 ( ,nitric ,acid ) f\r ( ,hydro*loric ,acid1 & to dilute ) an equal bulk ( wat]4 ,! application ( a g5tle heat assi/s ! solution ( ! metal2 b if ! temp]ature rises to ! boil+ po9t1 a viol5t eff]vesc5ce & escape ( ,*lor9e takes place4 ,,nitro-,,sulphuric ,,acid4 ,= ! *emi/ry ( ?is acid liquid1 see page #gg4 ,,oxyg54 ,symbol1 ,o4 ,atomic weight1 #h4 ,oxyg5 gas may be obta9$ by heat+ ,nitrate ( ,pota% to r$ness1 b 9 ?is case x is contam9at$ ) a portion ( ,nitrog54 ,! salt t]m$ ,*lorate ( ,pota% 7! composition ( :i* is closely analog\s to t ( ! ,nitrate1 ,*lor9e be+ sub/itut$ = ,nitrog57 yields abundance ( pure ,oxyg5 gas on ! application ( heat1 leav+ beh9d ,*loride ( ,potassium4 ,*emical ,prop]ties4--,oxyg5 comb9es eag]ly ) _m ( ! *emical elem5ts1 =m+ ,oxides4 ,?is *emical aff9ity h[ev] is n well se5 :5 ! elem5t>y body is expos$ to ! action ( ,oxyg5 9 ! gase\s =m4 ,x is ! nasc5t ,oxyg5 :i* acts mo/ p[]fully z an oxidiz]4 ,by nasc5t ,oxyg5 is meant ,oxyg5 on ! po9t ( sep>ation f o!r elem5t>y atoms ) :i* x 0 previ\sly associat$2 x may !n be consid]$ to be 9 ! liquid =m1 & h5ce x comes m p]fectly into contact ) ! p>ticles ( ! body to be oxidiz$4 ,illu/rations ( ! sup]ior *emical en]gy ( nasc5t ,oxyg5 are num]\s1 b none p]haps are m /rik+ ?an ! mild & gradual oxidiz+ influ5ce ex]t$ by atmosph]ic air1 z comp>$ ) ! viol5t action ( ,nitric ,acid & bodies ( t class :i* conta9 ,oxyg5 loosely comb9$4 ,,oxymel4 ,?is syrup ( ,honey & ,v9eg> is prep>$ z foll[s4 ,take ( ,honey #a p\nd4 ,acid1 ,acetic1 =tiss4 7,beaufoy's ,acid7 #aa dra*ms4 ,wat] #ac dra*ms4 ,/& ! pot conta9+ ! ,honey 9 boil+ wat] until a scum rises to ! surface1 :i* is to be remov$ two or ?ree times4 ,!n add ! ,acetic ,acid & wat]1 & skim once m if requir$4 ,all[ to cool1 & x w be fit = use4 ,,pota%4 ,symbol1 ,,ko ,,ho4 ,atomic weight1 #eg4 ,pota% is obta9$ by sep>at+ ! ,c>bonic ,acid f ,c>bonate ( ,pota% by means ( ,cau/ic ,lime4 ,lime is a m feeble base ?an ,pota%1 b ! ,c>bonate ( ,lime1 be+ insoluble 9 wat]1 is at once =m$ on add+ ,milk ( ,lime to a solution ( ,c>bonate ( ,pota% 7see page #cad74 ,prop]ties4--,usually met ) 9 ! =m ( solid lumps1 or 9 cyl9drical /icks1 :i* are =m$ by melt+ ! ,pota% & runn+ x into a m\ld4 ,x always conta9s "o atom ( wat]1 :i* _c be driv5 (f by ! application ( heat4 ,pota% is soluble almo/ to any ext5t 9 wat]1 mu* heat be+ evolv$4 ,! solution is p[]fully alkal9e 7p4 #cjh71 & acts rapidly ^u ! sk92 x dissolves fatty & res9\s bodies1 conv]t+ !m into soaps4 ,solution ( ,pota% absorbs ,c>bonic ,acid quickly f ! air1 & %\ld !re=e be pres]v$ 9 /opp]$ bottles2 ! glass /opp]s mu/ be wip$ occasionally1 9 ord] to prev5t !m f becom+ immovably fix$ by ! solv5t action ( ! ,pota% ^u ! ,silica ( ! glass4 ,! ,liquor ,potass ( ! ,london ,ph>macopia has a sp4 gr4 ( #ajfc1 & conta9s ab\t #e p] c5t1 ( real ,pota%4 ,x is usually contam9at$ ) ,c>bonate ( ,pota%1 :i* causes x to eff]vesce on ! addition ( acids2 also1 to a less ext5t1 ) ,sulphate ( ,pota%1 ,*loride ( ,potassium1 ,silica1 etc4 ,,pota%1 ,,c>bonate ,,(4 ,symbol1 ,,ko ,,co#b4 ,atomic weight1 #gj4 ,! impure ,c>bonate ( ,pota%1 t]m$ ,pe>la%1 is obta9$ f ! a%es ( wood & vegetable matt]1 9 ! same mann] z ,c>bonate ( ,soda is prep>$ f ! a%es ( seawe$s4 ,salts ( ,pota% & ( ,soda appe> ess5tial to vegetation1 & are absorb$ & approximat$ by ! liv+ tissues ( ! plant4 ,!y exi/ 9 ! vegetable /ructure1 comb9$ ) organic acids 9 ! =m ( salts1 l ! ,oxalate1 ,t>trate1 etc41 :i*1 :5 burn$ are conv]t$ into ,c>bonates4 ,prop]ties4--,! ,pe>la% ( comm]ce conta9s l>ge & v>iable quantities ( ,*loride ( ,potassium1 ,sulphate ( ,pota%1 etc4 ,a pur] ,c>bonate is sold1 :i* is free f ,sulphates1 & ) only a trace ( ,*lorides4 ,c>bonate ( ,pota% is a /rongly alkal9e salt1 deliquesc5t1 & soluble 9 twice its weight ( cold wat]2 insoluble 9 ,alcohol1 & employ$ to deprive x ( wat] 7see page #aif74 ,,pyrogallic ,,acid4 ,symbol1 ,c#h;,h#d,o#d 7,/5h\se74 ,atomic weight1 #hd4 ,! *emi/ry ( ,pyrogallic ,acid has be5 describ$ at page #bh4 ,,sel ,d',,or4 ,see ,gold1 ,hyposulphite (4 ,,silv]4 ,symbol1 ,ag4 ,atomic weight1 #ajh4 ,?is metal1 ! ,luna or ,diana ( ! al*emi/s1 is f\nd native 9 ,p]u & ,mexico2 x occurs also 9 ! =m ( ,sulphuret ( ,silv]4 ,:5 pure x has a sp4 gr4 ( #aje1 & is v malleable & ductile2 melts at a bright r$ heat4 ,silv] does n oxidize 9 ! air1 b :5 expos$ to an impure atmosph]e conta9+ traces ( ,sulphurett$ ,hydrog51 x is sl[ly t>ni%$ f =mation ( ,sulphuret ( ,silv]4 ,x dissolves 9 ,sulphuric ,acid1 b ! be/ solv5t is ,nitric ,acid4 ,! /&>d co9 ( ! realm is an alloy ( ,silv] & ,copp]1 conta9+ ab\t "o-elev5? ( ! latt] metal4 ,to prep>e pure ,nitrate ( ,silv] f x1 dissolve 9 ,nitric ,acid & evaporate until cry/als are obta9$4 ,!n wa% ! cry/als ) a little dilute ,nitric ,acid1 r$issolve !m 9 wat]1 & cry/allize by evaporation a second "t4 ,la/ly1 fuse ! product at a mod]ate heat1 9 ord] to expel ! la/ traces ( ,nitric & ,nitr\s ,acids4 ,,silv]1 ,,ammonio-,,nitrate ,,(4 ,cry/alliz$ ,nitrate ( ,silv] absorbs ,ammoniacal gas rapidly1 ) production ( heat suffici5t to fuse ! result+ comp\nd1 :i* is :ite1 & consi/s ( #ajj p>ts ( ! ,nitrate #bie ( ,ammonia4 ,! comp\nd h[ev] :i* ,photograph]s employ "u ! "n ( ,ammonio-,nitrate ( ,silv] may be view$ m simply z a solution ( ! ,oxide ( ,silv] 9 ,ammonia1 )\t ref]5ce to ! ,nitrate ( ,ammonia necess>ily produc$ 9 ! reaction4 ,v /rong ,ammonia1 9 act+ ^u ,oxide ( ,silv]1 conv]ts x into a black p[d]1 t]m$ ,fulm9at+ ,silv]1 :i* possesses ! mo/ dang]\s explosive prop]ties4 ,its composition is unc]ta94 ,9 prep>+ ,ammonio-,nitrate ( ,silv] by ! common process1 ! ,oxide fir/ precipitat$ occasionally leaves a little black p[d] beh9d1 on re-solution2 ?is does n appe> h[ev]1 accord+ to ! obs]vations ( ! ,au?or1 to be ,fulm9at+ ,silv]4 ,9 s5sitiz+ salt$ pap] by ! ,ammonio-,nitrate ( ,silv]1 free ,ammonia is necess>ily =m$4 ,?us-- ,*loride ( ,ammonium ,oxide ( ,silv] 9 ,ammonia ,*loride ( ,silv] ,ammonia ,wat]4 ,,silv]1 ,,oxide ,,(4 ,symbol1 ,ag,o4 ,atomic weight1 #aaf4 ,?is comp\nd has already be5 describ$ 9 ,"p ,i41 page #ag4 ,,silv]1 ,,*loride ,,(4 ,symbol1 ,ag,cl4 ,atomic weight1 #add4 ,! prep>ation & prop]ties ( ,*loride ( ,silv] are giv5 9 ,"p ,i4 page #ad4 ,,silv]1 ,,bromide ,,(4 ,symbol1 ,ag,br4 ,atomic weight1 #ahf4 ,see ,"p ,i4 page #ag4 ,,silv]1 ,,citrate ,,(4 ,see ,citric ,acid4 ,,silv]1 ,,iodide ,,(4 ,symbol1 ,ag,i4 ,atomic weight1 #bcd4 ,see ,"p ,i4 page #af4 ,,silv]1 ,,fluoride ,,(4 ,symbol1 ,ag,f4 ,atomic weight1 #abg4 ,?is comp\nd diff]s f ^? la/ describ$ 9 be+ soluble 9 wat]4 ,! dry salt fuses on be+ heat$1 & is r$uc$ by a high] temp]ature1 or by exposure to light4 ,,silv]1 ,,sulphuret ,,(4 ,symbol1 ,ag,s4 ,atomic weight1 #abd4 ,?is comp\nd is =m$ by ! action ( ,sulphur ^u metallic ,silv]1 or ( ,sulphurett$ ,hydrog5 or ,hydrosulphate ( ,ammonia ^u ! ,silv] salts2 ! decomposition ( ,hyposulphite ( ,silv] also furni%es ! black ,sulphuret4 ,sulphuret ( ,silv] is insoluble 9 wat]1 & ne>ly s 9 ^? sub/ances :i* dissolve ! ,*loride1 ,bromide1 & ,iodide1 su* z ,ammonia1 ,hyposulphites1 ,cyanides1 etc42 b x dissolves 9 ,nitric ,acid1 be+ conv]t$ into soluble ,sulphate & ,nitrate ( ,silv]4 7,= a fur!r acc\nt ( ! prop]ties ( ! ,sulphuret ( ,silv]1 see page #adf47 ,,silv]1 ,,nitrate ,,(4 ,symbol1 ,ag,o ,,no#e4 ,atomic weight1 #agj4 ,! prep>ation & prop]ties ( ?is salt h be5 expla9$ at pages #ab & #cfb4 ,,silv]1 ,,nitrite ,,(4 ,symbol1 ,ag,o ,,no#c4 ,atomic weight1 #aed4 ,nitrite ( ,silv] is a comp\nd ( ,nitr\s ,acid1 or ,,no#c1 ) ,oxide ( ,silv]4 ,x is =m$ by heat+ ,nitrate ( ,silv]1 s z to drive (f a portion ( its ,oxyg51 or m conv5i5tly1 by mix+ ,nitrate ( ,silv] & ,nitrite ( ,pota% 9 equal p>ts1 fus+ /rongly1 & dissolv+ 9 a small quantity ( boil+ wat]3 on cool+1 ! ,nitrite cry/allizes out1 & may be purifi$ by press+ 9 blott+-pap]4 ,mr4 ,had[ describes an economical me?od ( prep>+ ,nitrite ( ,silv] 9 quantity1 viz4 by heat+ #a "p ( ,/>* 9 #h ( ,nitric ,acid ( #abe specific gravity1 & conduct+ ! evolv$ gases into a solution ( pure ,c>bonate ( ,soda until eff]vesc5ce has ceas$4 ,! ,nitrite ( ,soda ?us =m$ is aft]w>ds add$ to ,nitrate ( ,silv] 9 ! usual way4 ,prop]ties4--,nitrite ( ,silv] is soluble 9 #abj p>ts ( cold wat]2 easily soluble 9 boil+ wat]1 & cry/allizes1 on cool+1 9 long sl5d] ne$les4 ,x has a c]ta9 degree ( aff9ity = ,oxyg51 & t5ds to pass into ! condition ( ,nitrate ( ,silv]2 b x is probable t its ,photographic prop]ties dep5d m ^u a decomposition ( ! salt & lib]ation ( ,nitr\s ,acid4 ,prop]ties ( ,nitr\s ,acid4--,?is sub/ance possesses v feeble acid prop]ties1 its salts be+ decompos$ ev5 by ,acetic ,acid4 ,x is an un/able body1 & splits up1 9 contact ) wat]1 into ,b9oxide ( ,nitrog5 & ,nitric ,acid4 ,! ,p]oxide ( ,nitrog51 ,,no#d1 is also decompos$ by wat]1 & yields ! same products4 ,,silv]1 ,,acetate ,,(4 ,symbol1 ,ag,o 7,c#d;,h#c,o#c74 ,atomic weight1 #afg4 ,?is is a difficultly soluble salt1 deposit$ 9 lamell> cry/als :5 an ,acetate is add$ to a /rong solution ( ,nitrate ( ,silv]4 ,if ,acetic ,acid be us$ 9 place ( an ,acetate1 ! ,acetate ( ,silv] does n fall s readily1 s9ce ! ,nitric ,acid :i* w\ld !n be lib]at$ imp$es ! decomposition4 ,its prop]ties h be5 suffici5tly describ$ at page #hi4 ,,silv]1 ,,hyposulphite ,,(4 ,symbol1 ,ag,o ,s#b,o#b4 ,atomic weight1 #afd4 ,?is salt is fully describ$ 9 ,"p ,i4 page #abi4 ,= ! prop]ties ( ! soluble d\ble salt ( ,hyposulphite ( ,silv] & ,hyposulphite ( ,soda1 see page #dc4 ,,sug> ,,( ,,milk4 ,see ,milk4 ,,sulphurett$ ,,hydrog54 ,see ,hydrosulphuric ,acid4 ,,sulphuric ,,acid4 ,symbol1 ,,s#c4 ,atomic weight1 #dj4 ,sulphuric ,acid may be =m$ by oxidiz+ ,sulphur ) boil+ ,nitric ,acid2 b ?is plan w\ld be too exp5sive to be adopt$ on a l>ge scale4 ,! comm]cial process = ! manufacture ( ,sulphuric ,acid is exce$+ly +5i\s & beautiful1 b x involves reactions :i* are too complicat$ to admit ( a sup]ficial explanation4 ,! ,sulphur is fir/ burnt into gase\s ,sulphur\s ,acid 7,,s#b71 & !n by ! ag5cy ( ,b9oxide ( ,nitrog5 gas1 an additional atom ( ,oxyg5 is imp>t$ f ! atmosph]e1 s z to conv]t ! ,,s#b into ,,s#c1 or ,sulphuric ,acid4 ,prop]ties4--,anhydr\s ,sulphuric ,acid is a :ite cry/all9e solid4 ,! /ronge/ liquid acid always conta9s "o atom ( wat]1 :i* is closely associat$ ) x1 & _c be driv5 (f by ! application ( heat4 ,?is mono-hydrat$ ,sulphuric ,acid1 repres5t$ by ! =mula ,,ho ,,s#c1 is a d5se fluid1 hav+ a specific gravity ( ab\t #ahde2 boils at #fbj1 & di/ils )\t decomposition4 ,x is n volatile at common temp]atures1 & !re=e does n fume 9 ! same mann] z ,nitric or ,hydro*loric ,acid4 ,! conc5trat$ acid maybe cool$ d[n ev5 to z]o )\t solidify+2 b a weak] comp\nd1 conta9+ twice ! quantity ( wat]1 & t]m$ glacial ,sulphuric ,acid1 cry/allizes at #dj ,fahr4 ,sulphuric ,acid is int5sely acid & cau/ic1 b x does n de/roy ! sk9 or dissolve metals s readily z ,nitric ,acid4 ,x has an en]getic attraction = wat]1 & :5 ! two are mix$1 cond5sation ensues1 & mu* heat is evolv$2 f\r p>ts ( acid & "o ( wat] produce a temp]ature equal to t ( boil+ wat]4 ,mix$ ) aque\s ,nitric ,acid1 x =ms ! comp\nd "k a z ,nitro-,sulphuric ,acid4 ,sulphuric ,acid possesses int5se *emical p[]s1 & displaces ! great] numb] ( ord9>y acids f _! salts4 ,x *>s organic sub/ances1 by remov+ ! elem5ts ( wat]1 & conv]ts ,alcohol into ,e!r 9 a simil> mann]4 ,! /r5g? ( a giv5 sample ( ,sulphuric ,acid may be calculat$1 ne>ly1 f its specific gravity1 & a ,table is giv5 by ,dr4 ,ure = t purpose4 7,see ,app5dix47 ,impurities ( ,comm]cial ,sulphuric ,acid4--,! liquid acid sold z ,oil ( ,vitriol is tol]ably con/ant 9 composition1 & seems to be z well adapt$ = ,photographic use z ! pure ,sulphuric ,acid1 :i* is f> m exp5sive4 ,! specific gravity %\ld be ab\t #ahcf at #fj4 ,if a drop1 evaporat$ ^u ,plat9um-foil1 gives a fix$ residue1 probably ,bisulphate ( ,pota% is pres5t4 ,a milk9ess1 on dilution1 indicates ,sulphate ( ,lead 7see page #ahf74 ,te/ = ,sulphuric ,acid4--,if ! pres5ce ( ,sulphuric ,acid1 or a soluble ,sulphate1 be suspect$ 9 any liquid1 x is te/$ = by add+ a few drops ( dilute solution ( ,*loride ( ,b>ium1 or ,nitrate ( ,b>yta4 ,a :ite precipitate1 insoluble 9 ,nitric ,acid1 indicates ,sulphuric ,acid4 ,if ! liquid to be te/$ is v acid1 f ,nitric or ,hydro*loric ,acid1 x mu/ be l>gely dilut$ be=e te/+1 or a cry/all9e precipitate w =m1 caus$ by ! sp>+ solubility ( ! ,*loride ( ,b>ium itself 9 acid solutions4 ,,sulphur\s ,,acid4 ,symbol1 ,,s#b4 ,atomic weight1 #cb4 ,?is is a gase\s comp\nd1 =m$ by burn+ ,sulphur 9 atmosph]ic air or ,oxyg5 gas3 also by heat+ ,oil ( ,vitriol 9 contact ) metallic ,copp]1 or ) ,*>coal4 ,:5 an acid ( any k9d is add$ to ,hyposulphite ( ,soda1 ,sulphur\s ,acid is =m$ z a product ( ! decomposition ( ,hyposulphur\s ,acid1 b x aft]w>ds disappe>s f ! liquid by a second>y reaction1 result+ 9 ! production ( ,tri?ionate & ,tetra?ionate ( ,soda4 ,prop]ties4--,sulphur\s ,acid possesses a peculi> & suffocat+ od\r1 famili> to all 9 ! fumes ( burn+ ,sulphur4 ,x is a feeble acid1 & escapes ) eff]vesc5ce1 l ,c>bonic ,acid1 :5 its salts are treat$ ) ,oil ( ,vitriol4 ,x is soluble 9 wat]4 ,,tetra?ionic ,,acid4 ,symbol1 ,s#d,o#e4 ,atomic weight1 #ajd4 ,! *emi/ry ( ! ,poly?ionic ,acids & _! salts w be f\nd describ$ 9 ! ,fir/ ,"p ( ?is ,"w1 page #aeg4 ,,wat]4 ,symbol1 ,,ho4 ,atomic weight1 #i4 ,wat] is an ,oxide ( ,hydrog51 conta9+ s+le atoms ( ea* ( ! gases4 ,di/ill$ wat] is wat] :i* has be5 vaporiz$ & aga9 cond5s$2 by ?is means x is fre$ f e>?y & sal9e impurities1 :i*1 n be+ volatile1 are left 9 ! body ( ! retort4 ,pure di/ill$ wat] leaves no residue on evaporation1 & %\ld rema9 p]fectly cle> on ! addition ( ,nitrate ( ,silv]1 ev5 :5 expos$ to ! light2 x %\ld also be neutral to te/-pap]4 ,! cond5s$ wat] ( /eam-boil]s sold z di/ill$ wat] is apt to be contam9at$ ) oily & empyreumatic matt]1 :i* discol\rs ,nitrate ( ,silv]1 & is !re=e injuri\s4 ,ra9-wat]1 hav+ und]gone a natural process ( di/illation1 is free f inorganic salts1 b x usually conta9s a m9ute portion ( ,ammonia1 :i* gives x an alkal9e reaction to te/-pap]4 ,x is v good = ,photographic purposes if collect$ 9 clean vessels1 b :5 tak5 f a common ra9-wat] tank %\ld always be exam9$1 & if mu* organic matt] be pres5t1 t+e+ x ( a br[n col\r & imp>t+ an unpleasant smell1 x mu/ be reject$4 ,spr+ or ,riv] wat]1 commonly kn[n z h>d wat]1 usually conta9s ,sulphate ( ,lime1 & ,c>bonate ( ,lime dissolv$ 9 ,c>bonic ,acid2 also ,*loride ( ,sodium 9 great] or less quantity4 ,on boil+ ! wat]1 ! ,c>bonic ,acid gas is evolv$1 & ! great] "p ( ! ,c>bonate ( ,lime 7if any is pres5t7 deposits1 =m+ an e>?y incru/ation on ! boil]4 ,9 te/+ wat] = ,sulphates & ,*lorides1 acidify a portion ) a few drops ( pure ,nitric ,acid1 free f ,*lor9e 7if ?is is n at h&1 use pure ,acetic ,acid72 !n divide x into two p>ts1 & add to ! fir/ a dilute solution ( ,*loride ( ,b>ium1 & to ! second1 ,nitrate ( ,silv]1--a milk9ess indicates ! pres5ce ( ,sulphates 9 ! fir/ case or ( ,*lorides 9 ! second4 ,! ,photographic ,nitrate ,ba? _c be us$ z a te/1 s9ce ! ,iodide ( ,silv] x conta9s is precipitat$ on dilution1 giv+ a milk9ess :i* might be mi/ak5 = ,*loride ( ,silv]4 ,common h>d wat] c (t5 be us$ = mak+ a ,nitrate ,ba? :5 no?+ bett] is at h&4 ,! ,*lorides x conta9s are precipitat$ by ! ,nitrate ( ,silv]1 leav+ soluble ,nitrates 9 solution1 :i* are n injuri\s4 ,! ,c>bonate ( ,lime1 if any is pres5t1 neutralizes free ,nitric ,acid1 r5d]+ ! ,ba? alkal9e 9 ! same mann] z ,c>bonate ( ,soda4 7,see page #hi47 ,sulphate ( ,lime1 usually pres5t 9 well wat]1 is said to ex]cise a ret>d+ action ^u ! s5sitive ,silv] ,salts1 b on ?is po9t ! writ] is unable to give c]ta9 in=mation4 ,h>d wat] is n (t5 suffici5tly pure = ! develop+ fluids4 ,! ,*loride ( ,sodium x conta9s decomposes ! ,nitrate ( ,silv] ^u ! film1 & ! image _c be br\ght out p]fectly4 ,! ,new ,riv] wat]1 h[ev]1 suppli$ to _m p>ts ( ,london1 is almo/ free f ,*lorides1 & answ]s v well4 ,9 o!r cases a few drops ( ,nitrate ( ,silv] solution may be add$1 to sep>ate ! ,*lor9e1 tak+ c>e n to use a l>ge excess4 ,,app5dix4 ,,quantitative ,,te/+ ,,( ,,solutions ,,( ,,nitrate ,,( ,,silv]4 ,! am\nt ( ,nitrate ( ,silv] conta9$ 9 solutions ( t salt may be e/imat$ ) suffici5t delicacy = ord9>y ,photographic op]ations by ! foll[+ simple process4 ,take ! pure cry/alliz$ ,*loride ( ,sodium1 & ei!r dry x /rongly or fuse x at a mod]ate heat1 9 ord] to drive (f any wat] :i* may be reta9$ betwe5 ! int]/ices ( ! cry/als2 !n dissolve 9 di/ill$ wat]1 9 ! proportion ( #h-a_/b gra9s to #f fluid ounces4 ,9 ?is way1 a /&>d solution ( salt is =m$1 ea* dra*m ( :i* 7conta9+ slightly m ?an "o-six? ( a gra9 ( salt7 w precipitate exactly half a gra9 ( ,nitrate ( ,silv]4 ,9 ord] to use x1 measure out accurately "o dra*m ( ! ,ba? 9 a m9im measure & place x 9 a two-ounce /opp]$ phial1 tak+ c>e to r9se out ! measure ) a dra*m ( di/ill$ wat]1 :i* is to be add$ to ! =m]2 !n p\r 9 ! salt solution1 9 ! proportion ( a dra*m = e #d gra9s ( ,nitrate kn[n to be pres5t 9 an ounce ( ! ,ba? :i* is to be te/$2 %ake ! cont5ts ( ! bottle briskly1 until ! :ite curds h p]fectly sep>at$1 & ! sup]natant liquid is cle> & col\rless2 !n add fre% portions ( ! /&>d solution1 by #cj m9ims at a "t1 ) con/ant %ak+4 ,:5 ! la/ addition causes no milk9ess1 read (f ! total numb] ( dra*ms employ$ 7! la/ half-dra*m be+ subtract$71 & multiply t numb] by #d = ! weight 9 gra9s ( ! ,nitrate ( ,silv] pres5t 9 an ounce ( ! ,ba?4 ,9 ?is mann] ! /r5g? ( ! ,ba? is indicat$ )9 two gra9s to ! ounce1 or ev5 to a s+le gra9 if ! la/ additions ( /&>d salt-solution be made 9 portions ( #ae1 in/ead ( #cj m9ims4 ,suppos+ ! ,ba? to be te/$ is ?\ght to conta9 ab\t #ce gra9s ( ,nitrate to ! ounce1 x w be conv5i5t to beg9 by add+ to ! measur$ dra*m1 #g dra*ms ( ! /&>d solution2 aft]w>ds1 z ! milk9ess & precipitation become less m>k$1 ! process mu/ be c>ri$ on m cauti\sly1 & ! bottle %ak5 viol5tly = sev]al m9utes1 9 ord] to obta9 a cle> solution4 ,a few drops ( ,nitric ,acid add$ to ! ,nitrate ( ,silv] facilitate ! deposition ( ! ,*loride2 b c>e mu/ be tak5 t ! sample ( ,nitric ,acid employ$ is pure & free f ,*lor9e1 ! pres5ce ( :i* w\ld cause an error4 ,,recov]y ,,( ,,silv] ,,f ,,wa/e ,,solutions1--,,f ,,! ,,black ,,deposit ,,( ,,hypo-,,ba?s1 ,,etc4 ,! mann] ( sep>at+ metallic ,silv] f wa/e solutions v>ies accord+ to ! pres5ce or abs5ce ( alkal9e ,hyposulphites & ,cyanides4 a4 ,sep>ation ( metallic ,silv] f old ,nitrate ,ba?s4--,! ,silv] conta9$ 9 solutions ( ! ,nitrate1 ,acetate1 etc4 may easily be precipitat$ by susp5d+ a /rip ( %eet ,copp] 9 ! liquid2 ! action is complet$ 9 two or ?ree days1 ! :ole ( ! ,nitric ,acid & ,oxyg5 pass+ to ! ,copp]1 & =m+ a blue solution ( ! ,nitrate ( ,copp]4 ,! metallic ,silv] h[ev]1 sep>at$ 9 ?is mann]1 always conta9s a portion ( ,copp]1 & gives a blue solution :5 dissolv$ 9 ,nitric ,acid4 ,a bett] process is to comm5ce by precipitat+ ! ,silv] entirely 9 ! =m ( ,*loride ( ,silv]1 by add+ common ,salt until no fur!r milk9ess c be produc$4 ,if ! liquid is well /irr$1 ! ,*loride ( ,silv] s9ks to ! bottom1 & may be wa%$ by repeat$ly fill+ ! vessel ) common wat]1 & p\r+ (f ! upp] cle> portion :5 ! clots h aga9 settl$ d[n4 ,! ,*loride ( ,silv] ?us =m$ may aft]w>ds be r$uc$ to metallic ,silv] by a process :i* w pres5tly be describ$ 7p4 #cgd74 b4 ,sep>ation ( ,silv] f solutions conta9+ alkal9e ,hyposulphites1 ,cyanides1 or ,iodides4--,9 ?is case ! ,silv] _c be precipitat$ by add+ ,*loride ( ,sodium1 s9ce ! ,*loride ( ,silv] is soluble 9 su* liquids4 ,x is necess>y !re=e to use ! ,sulphurett$ ,hydrog51 or ! ,hydrosulphate ( ,ammonia1 & to sep>ate ! ,silv] 9 ! =m ( ,sulphuret4 ,sulphurett$ ,hydrog5 gas is readily prep>$1 by fitt+ a cork & flexible tub+ to ! neck ( a p9t bottle1 & hav+ introduc$ ,sulphuret ( ,iron 7sold by op]ative *emi/s = ! purpose71 ab\t z mu* z w /& 9 ! palm ( ! h&1 p\r+ ^u x #a-a_/b fluid ounce ( ,oil ( ,vitriol dilut$ ) #aj ounces ( wat]4 ,! gas is g5]at$ gradually )\t ! application ( heat1 & mu/ be all[$ to bubble up ?r\gh ! liquid f :i* ! ,silv] is to be sep>at$4 ,! smell ( ,sulphurett$ ,hydrog5 be+ (f5sive1 & highly poison\s if inhal$ 9 a conc5trat$ =m1 ! op]ation mu/ be c>ri$ on 9 ! op5 air1 or 9 a place :]e ! fumes may escape )\t do+ injury4 ,:5 ! liquid beg9s to acquire a /rong & p]si/5t od\r ( ,sulphurett$ ,hydrog51 ! precipitation ( ,sulphuret is complet$4 ,! black mass mu/ !n be collect$ ^u a filt]1 & wa%$ by p\r+ wat] ov] x1 until ! liquid :i* runs ?r\gh gives little or no precipitate ) a drop ( ,nitrate ( ,silv]4 ,! ,silv] may also be sep>at$ 9 ! =m ( ,sulphuret f old ,hypo-,ba?s1 by add+ ,oil ( ,vitriol 9 quantity suffici5t to decompose ! ,hyposulphite ( ,soda2 & burn+ (f ! free ,sulphur f ! br[n deposit4 ,conv]sion ( ,sulphuret ( ,silv] into metallic ,silv]4--,! black ,sulphuret ( ,silv] may be r$uc$ to ! /ate ( metal by roa/+ & subsequ5t fusion ) ,c>bonate ( ,soda2 b x is m conv5i5t1 9 op]at+ on a small scale1 to proce$ 9 ! foll[+ mann]3--fir/ conv]t ! ,sulphuret into ,nitrate ( ,silv]1 by boil+ ) ,nitric ,acid dilut$ ) two p>ts ( wat]2 :5 all evolution ( r$ fumes has ceas$1 ! liquid may be dilut$1 all[$ to cool1 & filt]$ f ! insoluble portion1 :i* consi/s pr9cipally ( ,sulphur1 b also conta9s a mixture ( ,*loride & ,sulphuret ( ,silv]1 unless ! ,nitric ,acid employ$ 0 free f ,*lor9e2 ?is precipitate may be heat$1 9 ord] to volatilize ! ,sulphur1 & !n dige/$ ) ,hyposulphite ( ,soda1 or add$ to ! ,hypo-,ba?4 ,! solution ( ,nitrate ( ,silv] obta9$ by dissolv+ ,sulphuret ( ,silv]1 is always /rongly acid ) ,nitric ,acid1 & also conta9s ,sulphate ( ,silv]4 ,x may be cry/alliz$ by evaporation2 b unless ! quantity ( mat]ial op]at$ on is l>ge1 x w be bett] to precipitate ! ,silv] 9 ! =m ( ,*loride1 by add+ common ,salt1 z already recomm5d$4 ,,r$uction ,,( ,,*loride ,,( ,,silv] ,,to ,,! ,,metallic ,,/ate4 ,! ,*loride ( ,silv] is fir/ to be c>efully wa%$1 by fill+ up ! vessel :i* conta9s x1 _m times ) wat]1 & p\r+ (f ! liquid1 or draw+ x (f close ) a siphon4 ,x may !n be dri$ at a g5tle heat1 & fus$ ) twice its weight ( dry ,c>bonate ( ,pota%1 or bett] /ill1 ) a mixture ( ! ,c>bonates ( ,pota% & ,soda4 ,! process = r$uc+ ,*loride ( ,silv] 9 ! moi/ way1 by metallic ,z9c & ,sulphuric ,acid1 is m economical & less tr\blesome ?an t j giv52 x is conduct$ z foll[s3--,! ,*loride1 aft] hav+ be5 well wa%$ z be=e1 is plac$ 9 a l>ge flat di%1 & a b> ( metallic ,z9c laid 9 contact ) x4 ,a small quantity ( ,oil ( ,vitriol1 dilut$ ) f\r p>ts ( wat]1 is !n add$1 until a slight eff]vesc5ce ( ,hydrog5 gas is se5 to take place4 ,! vessel is set aside = two or ?ree days1 & is n to be di/urb$1 ei!r by /irr+ or by mov+ ! b>4 ,! r$uction beg9s ) ! ,*loride imm$iately 9 contact ) ! ,z9c1 & radiates 9 all directions4 ,:5 ! :ole mass has become ( a grey col\r1 ! b> is to be c>efully remov$ & ! adh]+ ,silv] wa%$ (f ) a /ream ( wat]2 ! ,z9c usually pres5ts a honeycomb$ appe>ance1 ) irregul>ities ^u ! surface1 :i* h[ev] are n metallic ,silv]2--!y consi/ only ( ,z9c or ( ,oxide ( ,z9c4 ,9 ord] to ensure ! purity ( ! ,silv]1 a fre% addition ( ,sulphuric ,acid mu/ be made1 aft] ! ,z9c b> has be5 remov$1 & ! dige/ion cont9u$ = sev]al h\rs1 9 ord] to dissolve any fragm5ts ( metallic ,z9c :i* may h be5 inadv]t5tly deta*$4 ,! grey p[d] mu/ be repeat$ly wa%$1 fir/ ) ,sulphuric ,acid & wat] 7?is is necess>y to dissolve a portion ( an insoluble ,salt ( ,z9c1 probably an oxy*loride7 & !n ) wat] alone1 until ! liquid runs away neutral1 & gives no precipitate ) ,c>bonate ( ,soda2 x may !n be fus$ into a button1 to burn (f organic matt] if pres5t1 & subsequ5tly conv]t$ into ,nitrate ( ,silv] by boil+ ) ,nitric ,acid dilut$ ) two p>ts ( wat]4 ,9 r$uc+ ,*loride ( ,silv] precipitat$ f old ,nitrate ,ba?s conta9+ ,iodide ( ,silv]1 ! grey metallic p[d] is sometimes contam9at$ ) unr$uc$ ,iodide ( ,silv]1 :i* dissolves 9 ! solution ( ,nitrate ( ,silv] =m$ on treat+ ! mass ) ,nitric ,acid4 ,to avoid ?is1 wa% ! purifi$ ,silv] ) solution ( ,hyposulphite ( ,soda1 & !n aga9 ) wat]4 ,,mode ,,( ,,tak+ ,,! ,,specific ,,gravity ,,( ,,liquids4 ,in/rum5ts are sold1 t]m$ ,hydromet]s1 :i* indicate specific gravity by ! ext5t to :i* a glass bulb conta9+ air1 & prop]ly balanc$1 rises or s9ks1 9 ! liquid2 b a m exact process1 & "o equally simple1 is by ! use ( ! specific gravity bottle4 ,^! bottles are made to conta9 exactly #ajjj gra9s ( di/ill$ wat]1 & ) ea* is sold a brass weight1 :i* c\nt]balances x :5 fill$ ) pure wat]4 ,9 tak+ ! specific gravity ( a liquid1 fill ! bottle q full & ins]t ! /opp]1 :i* be+ pi]c$ ?r\gh by a f9e capill>y tube all[s ! excess to escape4 ,!n1 hav+ wip$ ! bottle q dry1 place x 9 ! scale-pan1 & asc]ta9 ! numb] ( gra9s requir$ to produce equilibrium2 ?is numb] add$ to1 or subtract$ f1 unity 7! assum$ specific gravity ( wat]71 w give ! d5sity ( ! liquid4 ,?us1 to take examples1 suppos+ ! bottle fill$ ) rectifi$ ,e!r to require #bej gra9s to enable x to c\nt]balance ! brass weight1--!n #a m9us #bej1 or #gej1 is ! specific gravity2 b 9 ! case ( ,oil ( ,vitriol ! bottle1 :5 full1 w be heavi] ?an ! c\nt]poise by p]haps #hcf gra9s2 !re=e #a plus #hcf1 id e/ #ahcf1 is ! d5sity ( ! sample exam9$4 ,sometimes ! bottle is made to hold only #ejj gra9s ( di/ill$ wat]1 9 place ( #ajjj2 9 ?is case ! numb] ( gra9s to be add$ or subtract$ mu/ be multipli$ by #b4 ,9 tak+ specific gravities1 obs]ve t ! temp]ature be )9 a few degrees ( #fj ,fahr5heit 7if high] or l[]1 imm]se ! bottle 9 w>m or cold wat]72 & wa% out ! bottle ?or\ghly ) wat] ea* "t aft] use4 ,,on ,,filtration ,,& ,,wa%+ ,,precipitates4 ,9 prep>+ filt]s1 cut ! pap] into squ>es ( a suffici5t size1 & fold ea* squ>e neatly ^u itself1 fir/ into a half-squ>e1 & !n aga91 at "r angles1 into a qu>t]-squ>e2--r\nd (f ! corn]s ) a pair ( scissors1 & op5 out ! filt] into a conical =m1 :5 x w be f\nd to drop exactly into ! funnel1 & to be uni=mly support$ ?r\gh\t4 ,be=e p\r+ 9 ! liquid1 always moi/5 ! filt] ) di/ill$ wat]1 9 ord] to exp& ! fibres2 if ?is precaution be neglect$1 ! pores are apt to become *ok$ 9 filt]+ liquids :i* conta9 f9ely divid$ matt] 9 susp5sion4 ,! solution to be filt]$ may be p\r$ g5tly d[n a glass rod1 held 9 ! left h& 7a silv] spoon may be us$1 9 case ( necessity1 = ,nitrate ,ba?s1 & all liquids n conta9+ ,nitric or ,hydro*loric ,acid71 & direct$ aga9/ ! side ( ! funnel1 ne> to ! upp] "p4 ,if x does n imm$iately run cle>1 x w usually d s on return+ x into ! filt] & all[+ x to pass ?r\gh a second "t4 ,mode ( ,wa%+ ,precipitates4--,collect ! precipitate ^u a filt] & dra9 (f z mu* ( ! "m-liquor z possible2 !n p\r 9 di/ill$ wat] by small portions at a "t1 all[+ ea* to p]colate ?r\gh ! deposit be=e add+ a fre% quantity4 ,:5 ! wat] passes ?r\gh p]fectly pure1 ! wa%+ is complete2 9 te/+ x1 a s+le drop may be laid ^u a /rip ( glass & all[$ to evaporate spontane\sly 9 a w>m place1 or ! prop] *emical reag5ts may be appli$1 & ! wa%+ cont9u$ until no impurity c be detect$4 ,?us1 = example1 9 wa%+ ! ,sulphuret ( ,silv] precipitat$ f a ,hypo-,ba? by means ( ,hydrosulphate ( ,ammonia1 ! process w be complet$ :5 ! wat] :i* runs ?r\gh causes no deposit ) a drop ( ,nitrate ( ,silv] solution4 ,,on ,,! ,,use ,,( ,,te/-,,pap]s4 ,! nature ( ! col\r+ matt] :i* is employ$ 9 ! prep>ation ( litmus-pap] has already be5 describ$ at page #cec4 ,9 te/+ = ! alkalies & basic oxides g5]ally1 ! blue litmus-pap] :i* has be5 r$d5$ by an acid may be us$1 or1 9 place ( x1 ! turm]ic-pap]4 ,turm]ic is a yell[ vegetable sub/ance :i* possesses ! prop]ty ( becom+ br[n :5 treat$ ) an alkali2 x is h[ev] less s5sitive ?an ! r$d5$ litmus1 & is sc>cely affect$ by ! weak] bases1 su* z ,oxide ( ,silv]4 ,9 us+ te/-pap]s1 obs]ve ! foll[+ precautions3--!y %\ld be kept 9 a d>k place1 & protect$ f ! action ( ! air1 or !y soon become purple f ,c>bonic ,acid1 always pres5t 9 ! atmosph]e 9 small quantity4 ,by imm]sion 9 wat] conta9+ ab\t "o drop ( ,liquor ,potass or ,ammoni1 or a gra9 ( ,c>bonate ( ,soda to f\r ounces1 ! blue col\r is re/or$4 ,z ! quantities :i* are te/$ = 9 ,photography are (t5 inf9itesimally small1 x is ess5tial t ! litmus-pap] %\ld be 9 good condition2 & te/-pap]s prep>$ ) por\s pap] w be f\nd to %[ ! col\r bett] ?an ^? ^u glaz$ or /rongly-siz$ pap]4 ,! mode ( employ+ ! pap] is z foll[s3--,place a small /rip 9 ! liquid to be exam9$3 if x becomes at once bright r$1 a /rong acid is pres5t2 b if x *anges sl[ly to a w9e-r$ t9t1 a weak acid1 su* z ,acetic or ,c>bonic1 is indicat$4 ,9 ! case ( ! ,photographic ,nitrate ,ba? fa9tly acidifi$ ) ,acetic ,acid1 a purple col\r only may be expect$1 & a decid$ r$ col\r w\ld sugge/ ! pres5ce ( ,nitric ,acid4 ,9 ! ,hypo fix+ & ton+ ,ba? :i* has acquir$ acidity1 ! litmus-pap] w p]haps r$d5 9 ab\t ?ree or f\r m9utes4 ,blue litmus-pap]s may be *ang$ to ! r$ pap]s us$ = alkalies by soak+ 9 wat] acidifi$ ) ,sulphuric ,acid1 "o drop to half a p9t2 or by hold+ = an in/ant ne> ! m\? ( a bottle conta9+ ,glacial ,acetic ,acid4 ,9 exam9+ a ,nitrate ,ba? = alkal9ity by means ( ! r$d5$ litmus-pap]1 at lea/ five or t5 m9utes %\ld be all[$ = ! action1 s9ce ! *ange ( col\r f r$ to blue takes place v sl[ly4 ,,removal ,,( ,,silv] ,,/a9s ,,f ,,! ,,h&s1 ,,l951 ,,etc4 ,! black /a9s ^u ! h&s caus$ by ,nitrate ( ,silv]1 may readily be remov$ by moi/5+ !m & rubb+ ) a lump ( ,cyanide ( ,potassium4 ,z ?is salt h[ev] is highly poison\s1 _m may pref] ! foll[+ plan3--,wet ! spot ) a saturat$ solution ( ,iodide ( ,potassium1 & aft]w>ds ) ,nitric ,acid 7! /rong ,nitric ,acid acts ^u ! sk9 & turns x yell[1 x mu/ !re=e be dilut$ ) two p>ts ( wat] be=e use72 !n wa% ) solution ( ,hyposulphite ( ,soda4 ,/a9s ^u :ite l95 may be easily remov$ by bru%+ !m ) a solution ( ,iod9e 9 ,iodide ( ,potassium1 & aft]w>ds wa%+ ) wat] & soak+ 9 ,hyposulphite ( ,soda1 or ,cyanide ( ,potassium1 until ! yell[ ,iodide ( ,silv] is dissolv$ out2 ! ,bi*loride ( ,m]cury 7neutral solution7 also answ]s well 9 _m cases1 *ang+ ! d>k spot to :ite 7p4 #aea74 ,a ,,table ,,%[+ ,,! ,,quantity ,,( ,,anhydr\s ,,acid ,,9 ,,dilute ,,sulphuric ,,acid ,,( ,,diff]5t ,,specific ,,gravities4 7,,ure47 ---------------------------------------- ----------------------- ,real ,acid ,real ,acid ,real ,acid ,specific 9 #ajj ,specific 9 #ajj ,specific 9 #ajj ,gravity4 p>ts ( !,gravity4 p>ts ( !,gravity4 p>ts ( ! ,liquid4 ,liquid4 ,liquid4 ---------------------------------------- ----------------------- #ahdhe #haed #ahaae #gcci #agabj #febc #ahdge #hjgb #ahjdc #gbeg #afiic #fddb #ahdfj #giij #agifb #gage #afhgj #fcfj #ahdci #giji #aghgj #gjid #afgej #fbgh #ahdaj #ghbh #agggd #gjab #affcj #faig #ahcgf #ggdf #agfgc #fica #afebj #faae #ahccf #gffe #agegj #fhdi #afdae #fjcd #ahbij #gehc #agdfe #fgfh #afcba #eieb #ahbcc #gejb #agcfj #ffhf #afbjd #ehga #ahagi #gdbj #agbde #ffje #afjij #eghi ---------------------------------------- ----------------------- ,a ,,table ,,%[+ ,,! ,,quantity ,,( ,,anhydr\s ,,acid ,,9 ,,! ,,liquid ,,nitric ,,acid ,,( ,,diff]5t ,,specific ,,gravities4 7,,ure47 ---------------------------------------- ----------------------- ,real ,acid ,real ,acid ,real ,acid ,specific 9 #ajj ,specific 9 #ajj ,specific 9 #ajj ,gravity4 p>ts ( !,gravity4 p>ts ( !,gravity4 p>ts ( ! ,liquid4 ,liquid4 ,liquid4 ---------------------------------------- ----------------------- #aejjj #gigjj #adfdj #ficci #adadg #ehigh #adihj #ghijc #adfjj #fhedb #adajg #ehaha #adifj #ghajf #adegj #fggde #adjfe #egchd #adidj #ggcji #adecj #ffidh #adjbc #efehg #adiaj #gfeab #adejj #ffaee #acigh #eegij #adhhj #gegae #addfj #feced #acide #ediic #adhej #gdiah #addbd #fdeeg #achhb #edaif #adhbj #gdaba #adche #fcgfj #achcc #eccii #adgij #gccbd #adcdf #fbifc #acghc #ebfjb #adgfj #gbebg #adcjf #fbaff #acgcb #eahje #adgcj #gagcj #adbfi #facfi #acfha #eajfh #adgjj #gjicc #adbbh #fjegb #acfcj #ejbaa #adfgj #gjacf #adahi #eigge #acegi #didad ---------------------------------------- ----------------------- ,,weights ,,& ,,measures4 ,troy1 or ,apo!c>ies' ,weight4 #a ,p\nd #ab ,ounces4 #a ,ounce #h ,dra*ms4 #a ,dra*m #c ,scruples4 #a ,scruple #bj ,gra9s4 7#a ,ounce ,troy #dhj ,gra9s1 or #a ,ounce ,avoirdupois plus #dbe gra9s47 ,avoirdupois ,weight4 #a ,p\nd #af ,ounces4 #a ,ounce #af ,dra*ms4 #a ,dra*m #bgcdc gra9s4 7#a ,ounce ,avoirdupois #dcge gra9s47 7#a ,p\nd ,avoirdupois #gjjj ,gra9s1 or #a ,p\nd ,troy plus #b-a_/b ,troy ,ounces plus #dj gra9s47 ,imp]ial ,measure4 #a ,gallon #h ,p9ts4 #a ,p9t #bj ,ounces4 #a ,ounce #h ,dra*ms4 #a ,dra*m #fj ,m9ims4 7,a ,w9e ,p9t ( wat] measures #af ,ounces1 & weighs a ,p\nd47 ,an ,imp]ial ,gallon ( wat] weighs #aj ,p\nds ,avoirdupois1 or #gj1jjj ,gra9s4 ,an ,imp]ial ,p9t ( wat] weighs #a-a_/d ,p\nd ,avoirdupois4 ,a fluid ,ounce ( wat] weighs #a ,ounce ,avoirdupois1 or #dcge ,gra9s4 ,a ,dra*m ( wat] weighs #edg ,gra9s4 ,fr5* ,measures ( ,weight4 #a ,kilogramme #ajjj ,grammes some?+ less ?an #b-a_/d ,p\nds ,avoirdupois4 #a ,gramme #aj ,decigrammes--#ajj ,c5tigrammes #ajjj ,milligrammes #aedcc ,engli% ,gra9s4 ,a ,gramme ( wat] measures #ag ,engli% ,m9ims1 ne>ly4 #ajjj ,grammes ( wat] measure #ce-a_/d ,engli% fluid ,ounces4 ,fr5* ,measures ( ,volume4 #a ,litre #ac ,decilitres #ajj ,c5tilitres #ajjj ,millilitres #ce-a_/d ,engli% fluid ,ounces4 #a ,litre #a ,cubic ,decimetre #ajjj ,cubic ,c5timetres4 #a ,cubic ,c5timetre #ag ,engli% ,m9ims4 ,a ,litre ( wat] weighs a ,kilogramme1 or some?+ less ?an #b-a_/d ,p\nds ,avoirdupois4 ,a ,cubic ,c5timetre ( wat] weighs a ,gramme4 ,,index4#ef #ef ,! prep>ation & prop]ties ( ! ,*emicals us$ 9 ,photography w be f\nd 9 ! ,alphabetical ,li/ comm5c+ at page #cbg4 ,ab]ration1 *romatic1 #ed2 sph]ical1 #ef4 ,accel]at+ ag5ts1 _! mode ( action 9 ,collodion expla9$1 #ie4 ,acetate ( ,silv]1 its prep>ation & =mula1 #cfe2 its =mation 9 ,nitrate ,ba? expla9$1 #hi2 ensures abs5ce ( free ,nitric ,acid1 #aaf2 t5ds slightly to fav\r fogg+ & spots1 #ajd2 contra-indicat$ = glass ,positives1 #aaa4 ,acetic ,acid1 prop]ties & mode ( te/+ purity (1 #cbg2 useful 9 prev5t+ fogg+1 #ajd2 9 r5d]+ ! developm5t sl[ & ev51 #ii2 does n coagulate ,album51 #cbi2 a good comm]cial =m ( acid1 #bab2 ,acetic ,acid ess5tial 9 ,calotype1 wax$ pap]1 & ,album5 processes1 #agg2 also 9 pr9t+ pap] ,positives by developm5t1 #bfj4 ,aceto-,nitrate ( ,silv]1 t]m expla9$1 #agg4 ,a*romatic ,l5ses1 _! con/ruction expla9$1 #ee2 ! visual & *emical foci (t5 co9cid5t 91 #fj4 ,acids1 nature (1 #cjh4 ,act9ism1 expla9$1 #fa2 importance ( di/+ui%+ ,act9ic f visual rays1 #fb2 mode ( f9d+ ,act9ic focus1 #bbi4 ,aff9ity1 *emical1 #cab4 ,album51 its *emi/ry1 #cbh2 =ms a comp\nd ) oxide ( ,silv]1 #bj2 us$ 9 ,positive pr9t+ to produce a f9e surface lay]1 #abb2 to increase s5sitiv5ess1 #abe2 affects ! col\r ( ! pr9ts1 #abg2 protects ! image f oxidation1 #aej2 putrifies :5 expos$ to moi/ure1 #aee2 discol\rs ! ,nitrate ,ba?1 #bde4 ,album5 negative process1 its inv5tion1 #aj2 !ory (1 #ahj2 ,collodio-,album5 process ( ,m4 ,taup5ot1 #bid4 ,album9iz$ pap]1 =mula =1 #bda2 sl[ 9 fix+1 #aca2 n well adapt$ = ton+ by ,sel d'or1 #bfi2 good = /]eoscopic subjects & small portraits1 #bdi2 _c be s5sitiz$ ) ,ammonio-,nitrate ( ,silv]1 #bdf4 ,alcohol1 its *emi/ry1 #ccj2 sometimes too dilute = mak+ ,collodion1 #hd2 mode ( rectify+1 #aif2 mu/ n conta9 impurities1 #if2 effects ( add+ to ,collodion1 #hd1 #if2 to develop]1 #bje4 ,alkalies1 nature (1 #cjh4 ,alkal9ity ( ,nitrate ,ba?1 expla9$1 #hh2 ! evils x produces1 #ajd2 h[ to te/ = x1 #cgg2 h[ to remove x1 #bgg4 ,amb] v>ni%1 #bbf4 ,ammonia1 prep>ation & prop]ties1 #cca2 its use 9 fix+1 #db2 ,mr4 ,%adbolt's =mula =1 #bga2 its action ^u ,*loride ( ,gold1 #cdc2 effect ( conc5trat$ ,ammonia ^u ,oxide ( ,silv]1 #cfb4 ,ammonio-,nitrate ( ,silv]1 its *emi/ry1 #bfb2 us$ 9 ,positive pr9t+ to increase s5sitiv5ess1 #abe2 to give black tones1 #abg2 _c be us$ ) ,album51 #bdf2 increases p]man5cy ( pr9t1 #afi2 old ,nitrate ,ba?s n easily conv]tible into ,ammonio-,nitrate1 #bdh2 mode ( prep>+1 #bdg2 be/ appli$ to ! pap] by bru% or rod1 #bdh2 ,oxide ( ,silv] 9 ,nitrate ( ,ammonia1 a useful sub/itute = x1 #bdi4 ,ammonio-,nitrate pap]1 =mula =1 #bdf2 a m simple =mula1 b less s5sitive ?an ! la/1 #beh4 ,atomic !ory expla9$1 #cbb4 ,ba? = fix+ & ton+ ,positives4 ,see ,fix+ & ton+ ,ba?4 ,bi*loride ( ,m]cury1 :it5+ action on glass ,positives expla9$1 #aac2 solution =1 #bjg2 us$ to int5sify ,negatives1 #aah2 blea*es pap] pr9ts1 #aea2 %\ld n be add$ to pa/e us$ 9 m\nt+ pr9ts1 #afd2 removes ,silv] /a9s1 #cgg4 ,b9ocul> vision1 ph5om5a (1 expla9$1 #ff4 ,black5+ ,negatives1 #cg1 #aag4 ,black tones1 mode ( obta9+1 9 pap] ,positives1 #afh1 #bdf4 ,bromide ( ,silv]1 its prep>ation & prop]ties1 #ag2 its sup]ior s5sibility to col\r$ light1 #fc2 less act$ on by :ite light ?an ,*loride1 #ai2 less s5sitive to invisible image ?an ,iodide1 #be2 employm5t 9 ,collodion1 #aja2 f\nd useful 9 ,photograph+ by artificial light1 #ff2 diagram ( *emical spectrum on1 #fd4 ,bromo-,iodide ( ,silv]1 #agc4 ,bru%es1 mode ( apply+ ,silv] solutions by1 #bdh4 ,calotype process1 !ory (1 #agf4 ,cam]a1 its fir/ inv5tion1 #g2 !ory ( its con/ruction1 #ed2 mode ( te/+ accuracy (1 #bbi2 cause ( ! image be+ inv]t$1 #ec2 ! t]m flatness ( field expla9$1 #ed2 be/ position ( ! ,cam]a = portraits1 #bbj2 = ar*itectural subjects1 #bca2 a funnel-%ap$ tube plac$ 9 front ( ! l5s1 #bbi2 /]eoscopic ,cam]a1 #bcd2 microscope ,cam]a1 #bcf4 ,causes ( failure 9 ,collodion process1 #bgf4 ,*emical aff9ity1 illu/rations (1 #cab4 ,*emical elem5ts1 #cjf4 ,*emical focus1 directions = f9d+1 #bbi2 %ort] ?an visual 9 non a*romatic l5ses1 #fj2 long] ?an visual 9 microscopic objectives1 #bcg2 v>ies slightly ) ! nature ( ! light1 #bch4 ,*emical spectrum1 #fa4 ,*emicals1 ,photographic1 ,vocabul>y (1 #cbg4 ,*loride ( ,silv]1 its prep>ation & prop]ties1 #ad2 m s5sitive to :ite light ?an ,bromide or ,iodide1 #ai2 less s5sitive to invisible image1 #bd2 its black5+ by light expla9$1 #bj1 #ada2 accel]at$ by excess ( ,nitrate1 #ai2 by organic matt]1 #bj1 #adb2 exp]im5ts illu/rat+ d>k5+ ( pap]s prep>$ )1 #ba2 simple explanation ( ! mode ( prep>+ s5sitive pap]s )1 #bb2 ag5ts :i* dissolve x1 #db2 mode ( r$uc+ x to metallic /ate4 #cgd4 ,*loride ( ,gold1 its prep>ation & prop]ties1 #cdb2 action ( ,ammonia ^u x1 #cdc2 use ( an alkal9e solution (1 = ton+1 #acb1 #bga2 comp\nds =m$ on add+ x to ,hyposulphite ( ,soda1 #acc2 mode ( prep>+ ! fix+ & ton+ ,ba? )1 #bej2 ! ,sel d'or ,ba? )1 #bfg4 ,*romatic ab]ration1 #ed4 ,citric ,acid1 =ms a r$ comp\nd ) ,suboxide ( ,silv]1 #ba1 #cch2 us$ 9 pr9t+ to give purple tones1 #abh2 =mula = prep>+ pap] )1 #bdf4 ,clean+ glass plates1 !ory (1 #ci2 details (1 #bac4 ,collodion1 its discov]y1 #aj2 *emi/ry ( ,pyroxyl9e1 #ge2 physical effect ( ,e!r & ,alcohol 91 #hc2 ( wat] 91 #he2 glut9osity (1 #hc2 coloration ( iodiz$1 expla9$1 #he2 s5sitiv5ess & int5sity affect$ by ! *ange1 #ig1 #ii2 details ( manufacture ( ,collodion1 #ahe2 ,positive ,collodion1 !ory (1 #ajh2 =mula =1 #bja2 ,negative ,collodion1 !ory (1 #aac2 =mula =1 #bjh2 ,collodion = copy+ engrav+s1 #bca2 = keep+ processes1 #bih2 = hot climates1 #baj2 = work+ by artificial light1 #bch2 to remove ! br[n col\r f ,collodion1 #hf4 ,collodion film1 ! prop] "t = imm]s+ x 9 ! ,ba?1 #bai2 a ?9 film (t5 good = direct ,positives1 #aji2 a ?ick] film = ,negatives1 #aac2 cause ( ! film fall+ away f ! glass1 #hc1 #bic2 spots & m>k+s on1 #bha2 conditions :i* affect its s5sitiv5ess to light1 #ib2 causes influ5c+ its behavi\r ) ! develop]1 #ih2 mode ( pres]v+ s5sitiv5ess ( film1 #bhi4 ,collodio-,album5 process1 !ory (1 #aha2 practical details (1 #bid4 ,col\rs1 _! nature expla9$1 #dg2 _! *emical action on s5sitive film1 #fd2 _! photographic action assi/$ by reflection ( :ite light1 #ff4 ,comb9ation1 laws (1 #cjg4 ,conjugate foci1 expla9$1 #eb1 #bgb4 ,crookes1 ,mr41 rem>ks ^u *emical spectrum1 #fc2 ^u wax$ pap] process1 #ahj2 pres]vative process = ,collodion films1 #bhi4 ,curvature ( lum9\s image =m$ by l5s1 expla9$1 #ec4 ,cyanide ( ,potassium1 its fix+ action expla9$1 #dd2 prep>ation ( solution (1 #bjg2 us$ to remove /a9s1 #cgg4 ,dagu]reotype1 its inv5tion1 #h2 !ory ( ! process1 #aga4 ,developm5t ( invisible image1 explanation (1 #cd-dj2 second1 or int5sify+ /age expla9$1 #cg2 details ( develop+ glass ,positives & ,negatives1 #bba-bbc2 developm5t ( pap] ,positives1 #bei2 conditions :i* increase or dim9i% rapidity ( developm5t1 #ih2 irregul>ities ( developm5t1 #ajc4 ,develop]s1 _! prep>ation & prop]ties1 #bf2 comp>ative /r5g? (1 #ih2 !ory (1 = ,positives1 #aaa2 = ,negatives1 #aag2 =mul = ,positive develop]s1 #bje2 = ,negative1 #baa4 ,diagrams1 mode ( copy+1 #bcb4 ,diaphragms = l5ses4 ,see ,/ops4 ,d\ble decomposition1 illu/rat$1 #ad2 expla9$1 #cad4 ,dry ,collodion process1 #bih4 ,elem5t>y bodies1 table (1 #cjf2 comb9ation (1 #cjg4 ,engrav+s1 mode ( copy+1 #bca2 (t5 yield d>k-col\r$ pr9ts1 #bee4 ,equival5t proportions1 #cbj4 ,e!r1 prop]ties (1 #cci2 purification (1 = ,photography1 #aie2 mu/ be kept 9 a d>k place1 #aif2 %\ld n be di/ill$ f residues ( old ,collodion1 #if4 ,exp]im5ts1 illu/rat+ action ( ,light ^u ,*loride ( ,silv]1 #ba2 illu/rat+ =mation & developm5t ( invisible images1 #be2 illu/rat+ photographic action ( col\r$ light1 #fb4 ,exposure 9 ! ,cam]a1 rules = ,positives1 #bba2 = ,negatives1 #bbe2 = pres]v$ ,collodion plates1 #bib2 = microscopic photographs1 #bch2 effects ( "u & ov]-expos+1 #ce2 exposure requir$ 9 ,calotype process1 #agg2 9 wax$ pap]1 #ahj2 9 ,album5 negative process1 #aha2 9 dry ,collodion process1 #cja2 9 ,taup5ot's process1 #big4 ,fad+ ( ,positives1 expla9$ at l5g?1 #afj2 ,au?or's rese>*es on1 #aec4 ,film1 s5sitive4 ,see ,collodion film4 ,filt]s1 mode ( cutt+1 #cgf4 ,fix+1 !ory (1 #da2 ( pap] pr9ts expla9$1 #abh2 solution = fix+ glass ,positives & ,negatives1 #bab2 manipulatory details ( fix+1 #bbe2 fix+ pap] ,positives ) ,ammonia1 #bga4 ,fix+ & ton+ ,ba?1 its prep>ation1 #bej2 conditions :i* fav\r or ret>d its action1 #ace2 c]ta9 /ates ( ! ,ba? injuri\s to ! pro(s1 #acf2 importance ( keep+ x 9 an active condition1 #afh2 mu/ n be employ$ imm$iately aft] mix+1 #bea2 mu/ n be all[$ to become acid by con/ant use1 #afh2 !ory ( ! gradual *ange ( prop]ties x und]goes1 #aef4 ,foci1 act9ic & lum9\s1 #fj2 act9ic1 mode ( f9d+1 #bbi2 v>iation betwe5 !m 9 microscopic objectives1 #bcg4 ,focuss+ ! object1 #bbj4 ,fogg+1 !ory (1 #ajc2 mode ( detect+ causes (1 #bgf4 ,=mul = solutions requir$ 9 ,collodion process1 #bja2 = pap]s us$ 9 ,positive pr9t+1 #bda2 want ( correspond5ce betwe51 #beg4 ,gallic ,acid1 its prep>ation & prop]ties1 #bg2 us$ 9 pap] processes1 #agh2 becomes m\ldy by keep+1 #bfa4 =mula = develop+ pap] ,positives )1 #bfa4 ,gallo-,nitrate ( ,silv]1 #agg2 discol\rs rapidly :5 develop+ di%es are n clean1 #agi4 ,gelat9e1 its prop]ties1 #cda2 =ms a comp\nd ) an ,oxide ( ,silv]1 #ba2 employ$ 9 dry ,collodion process1 #bii2 modifi$ =m (1 #cjb2 affects ! col\r 9 pr9t+ processes1 #abh2 us$ 9 ,positive pr9t+ to =m an ev5 surface lay]1 #abf2 z a cem5t to m\nt ,photographs1 #beg4 ,glass plates1 rules = clean+1 #ci2 details ( clean+1 #bac2 mode ( coat+ ) ,collodion1 #bae2 ) ,album51 #ahj4 ,glut9\s ,collodion1 expla9$1 #hc4 ,glycyrrhiz9e1 its nature1 #cdb2 its action 9 ,collodion1 #aad2 =mula = solution (1 #bji4 ,gold1 ,*loride (4 ,see ,*loride ( ,gold4 ,gold salts1 _! use 9 ,photographic pr9t+ expla9$1 #aca2 9 ! ,dagu]reotype process1 #age4 ,gradation ( tone1 9 ,collodion ,photographs1 affect$ by ! d5sity ( ! film1 #aji1 #aac2 by use ( ,glycyrrhiz9e1 #aae4 ,gradation ( tone1 9 pap] ,positives1 conditions affect+ x 9 pr9ts obta9$ by direct exposure1 #abc2 9 ,positives pr9t$ by developm5t1 #bff4 ,had[1 ,mr41 rese>*es on ,collodion1 #gg2 =mula = mak+ ,pyroxyl9e1 #ahg4 ,heliography1 inv5t$ by ,m4 ,nipce1 #g4 ,hi/orical sket* ( ,photography1 #f4 ,honey keep+ process1 #bhi4 ,hunt1 ,mr41 introduces ,protosalts ( ,iron 9 develop+1 #aaa4 ,hypo ,ba?4 ,see ,fix+ & ,ton+ ,ba?4 ,hyposulphite ( ,silv]1 its peculi> *anges 9 col\r1 #abi2 ! sweet comp\nd :i* x =ms ) ,hyposulphite ( ,soda1 #dd4 ,hyposulphite ( ,soda1 prep>ation & prop]ties1 #dc2 !ory ( its fix+ action1 #dc2 black5s ,nitrate ( ,silv]1 #abi2 causes a milk9ess ) acids1 #acg2 its decomposition by con/ant use 9 fix+1 #ach2 ! salts x =ms ) ,*loride ( ,gold1 #acc2 its conv]sion into sulphurett+ ,tetra?ionate by ,iod9e & ,p]*loride ( ,iron1 #aci2 te/ = pres5ce (1 #afi4 ,icel& moss1 its use 9 ,positive pr9t+1 #abh2 =mula = prep>+ pap] )1 #bde4 ,imp]fections 9 ,collodion ,negatives1 #bhb2 9 ,positives1 #bhd2 9 pap] ,positives1 #bhe4 ,int5sity1 explanation ( t]m1 #ib2 mode ( increas+ 9 ,negatives1 #ii1 #aad2 effect ( ,acetate ( ,silv] ^u1 #aaf2 ( ,nitrite ( ,silv] ^u1 #ajb2 mode ( dim9i%+1 9 glass ,positives1 #aji1 #aaj2 conditions affect+ int5sity 9 pap] ,positives1 #abc2 9 develop$ pap] ,positives1 #bff4 ,invisible images1 !ory ( =mation (1 #cd2 developm5t (1 #cf2 exp]im5ts illu/rat+1 #be4 ,iodate1 h[ =m$ 9 ,collodion film1 #id2 produces ins5sitiv5ess1 #aih4 ,iodide ( ,ammonium1 prep>ation (1 #aih2 n fitt$ = iodiz+ ,collodion requir$ to be kept long1 #baj4 ,iodide ( ,iron1 an accel]ator to ,collodion1 #aaf4 ,iodide ( ,potassium & ,silv]1 prop]ties (1 #db2 mode ( iodiz+ ,calotype pap]s by1 #agg4 ,iodide ( ,potassium1 te/s ( purity (1 #aig2 ext5t ( solubility 9 ,alcohol1 #cea2 dissolves ,iodide ( ,silv]1 #db4 ,iodide ( ,silv]1 its prep>ation & prop]ties1 #af2 unaffect$ by direct action ( light1 #ai2 highly s5sitive to invisible image1 #bd2 hypo!sis ( =mation ( lat5t image on1 #cd2 possibility ( its r$uction by ,pyrogallic ,acid %[n1 #cc2 excess ( ,nitrate ( ,silv] ess5tial to its black5+ by develop]1 #cf2 diagrams ( *emical spectrum on1 #fa1 #fd2 fix+ ag5ts =1 #db2 its solubility 9 ! ,nitrate ,ba?1 #hf2 ret>ds ! action ( ,hypo fix+ & ton+ ,ba?1 #acf2 sup]ior p]man5cy ( develop$ pr9ts on1 #afg2 details ( ,negative pr9t+ process on1 #bfc4 ,iod9e1 9 ,collodion1 dim9i%es s5sitiv5ess1 #id2 =ms ,nitric ,acid & ,iodate 9 ! ,ba?1 #id2 (t5 useful 9 ,positive ,collodion1 #aaj2 9 ,negative ,collodion1 if fogg+ occurs1 #aje2 mode ( remov+ f ,collodion1 #hf4 ,iodiz$ ,collodion4 ,see ,collodion4 ,kaol91 prop]ties (1 #cce2 us$ to decolorize ,nitrate ,ba?s1 #ia2 importance ( purify+ x be=e use1 #bde4 ,l&scape ,photography1 ) pres]v$ ,collodion plates1 #bhh4 ,lat5t image4 ,see ,invisible image4 ,laws ( sub/itution expla9$1 #gh4 ,le ,grey1 ,m11 8 ton+ process ) ,*loride ( ,gold1 #acb2 8 wax$ pap] ,negative process1 #agh4 ,l5ses1 v>i\s =ms (1 #ea2 foci (1 #eb2 =mation ( images by1 #ec2 use ( /ops1 #eh2 portrait1 #ei2 *emical foci (1 #fj2 *romatic ab]ration (1 #ed2 sph]ical ab]ration (1 #ef2 simple directions = us+ l5ses1 #bbg2 = f9d+ *emical focus1 #bbi4 ,light2 its action ^u ,silv] ,salts1 #ai2 exp]im5ts illu/rat+1 #ba2 =mation ( invisible images by1 #bd2 its alt]nat+ action ^u ,dagu]reotype plate1 #ci2 its comp\nd nature1 #df2 photographic action ( col\r$ light1 #fj2 refraction ( light1 #di4 ,llewellyn1 ,mr41 8 ,oxymel process1 #bia4 ,manipulations ( ,collodion process1 #bac2 ( ,photographic pr9t+1 #bea2 ( ton+ by ,sel d'or1 #bfg4 ,manuscripts1 mode ( copy+1 #bca4 ,m>k+s on ,collodion ,pictures1 #bha4 ,measures & ,weights1 #cgi4 ,microscopic ,photography1 #bce4 ,mos]1 ,m4 ,ludwig1 8 rese>*es on ! developm5t ( invisible images1 #cg4 ,m\nt+ ,positive ,pr9ts1 sub/ances :i* %\ld be avoid$ 91 #aee1 #afd2 details (1 #beg4 ,negative processes = pr9t+ ,positives1 #bei1 #bfc4 ,negatives1 def9ition (1 #ajf2 ,collodion ,negatives1 !ory ( production (1 #aac2 ,calotype1 #agf2 wax$ pap]1 #agh2 ,album51 #ahj2 ,collodio-,album5 7,taup5ot71 #aha2 mode ( develop+ ,collodion ,negatives1 #cg1 #aag1 #bbc2 ( conv]t+ ,positives into1 #aag2 =mula = solutions = ,negatives1 #bjh2 ! ,collodion be/ adapt$ = ,negatives1 #aad2 spots & m>k+s ^u ,negatives1 #bhb2 decomposition ( ,pyroxyl9e a cause ( fad+ (1 #aff4 ,nitrate ( ,silv]1 prep>ation & prop]ties (1 #ab2 prep>ation ( f /&>d co9 ( realm1 #cfb2 (t5 conta9s free ,nitric ,acid1 #ac2 :5 v /rongly fus$1 conta9s ,nitrite 7see ,nitrite ( ,silv]71 #ad2 n act$ on by light1 #ah2 its r$uction by ,pyrogallic ,acid expla9$1 #ca2 ! melt$ ,nitrate m c]ta9 9 its action1 #ac1 #aja2 its pres5ce ess5tial 9 develop+ ! image1 #cf1 #ih2 increases s5sitiv5ess ( ,collodion plate1 #ib2 dissolves ,iodide ( ,silv]1 #hf2 discol\r$ by ,album51 #bde1 #cbi2 =ms a comp\nd ) ,honey1 #bhi2 ) v>i\s o!r organic bodies1 #ba2 v little act$ on by ,glyc]9e1 #cdb2 mode ( recov]+ ! ,silv] f1 #cgb4 ,nitrate ,ba?1 mode ( prep>+ = glass ,positives1 #aaj1 #bjc2 = ,collodion ,negatives1 #aaf1 #baa2 its p[] ( dissolv+ ,iodide ( ,silv]1 its occasional acidity & alkal9ity expla9$1 #hf2 ! mode 9 :i* ,acetate ( ,silv] may be =m$ 9 x1 #hi2 a li/ ( ! sub/ances by :i* x is decompos$1 #ij2 *anges by use1 #ia2 effect ( ^! *anges on s5sitiv5ess1 #ig2 on int5sity1 #ajb2 c>e requir$ to prev5t x f yield+ foggy pictures1 #ajd2 a caution aga9/ ! too frequ5t addition ( alkali1 #bjd2 quantitative te/+ ( ! ,ba?1 #cga4 ,nitrite ( ,silv]1 adds to rapidity ( developm5t1 #ajb2 t5ds slightly to produce fogg+1 #ajd2 sol>izes ! high lights1 #aaa4 ,nitric ,acid1 its prep>ation & prop]ties1 #cee2 its oxidiz+ p[]s1 #ab2 impairs s5sitiv5ess ( ,collodion film1 #ic2 less5s rapidity ( developm5t1 #ih2 t5ds to prev5t fogg+1 #ajd2 sometimes usefully employ$ = glass ,positives1 #aaj2 contra-indicat$ = ,negatives1 #aaf2 its accumulation 9 ! ,nitrate ,ba? expla9$1 #id2 mode ( remov+ x1 #ij2 _c exi/ 9 contact ) ,acetate ( ,silv]1 #aaf2 produces /a9s on clo?1 #bae2 mode ( det]m9+ ! /r5g? ( ,comm]cial ,nitric ,acid1 #ahf2 table ( /r5g? ( ,nitric ,acid ( diff]5t d5sities1 #cgh4 ,nitro-,sulphuric ,acid1 expla9$1 #gg2 process = mak+ by mix$ acids1 #ahf2 by ,oil ( ,vitriol & ,nitre1 #aij2 %\ld n be us$ cold1 #hc4 ,nom5clature1 *emical1 #cae4 ,norris1 ,dr41 8 dry ,collodion process1 #bih4 ,notation1 *emical1 #cah4 ,organic bodies1 *emi/ry (1 #cbd4 ,oxide ( ,silv]1 prep>ation & prop]ties1 #ag2 dissolves 9 ! ,nitrate ,ba?1 r5d]+ x alkal9e1 #hh2 prop]ties ( its solution 9 ,ammonia1 #cfb2 prep>ation ( ditto1 #bdg2 its solution 9 ,nitrate ( ,ammonia us$ 9 ,photography1 #bdi4 ,oxymel1 keep+ process1 #bia2 prep>ation ( ,oxymel1 #cfj4 ,pap]1 ,photographic1 selection (1 #bdj2 peculi>ity ( ,engli% pap]s1 #bda4 ,pap]1 s5sitive1 = pr9t+4 ,see ,s5sitive ,pap]4 ,p]*loride ( ,iron1 prep>ation ( ton+ ,ba? )1 #afj4 ,p]man5ce ( ,positives1 mode ( te/+1 #afi4 ,photographic image1 *emical composition (1 #adj2 action ( de/ructive te/s on1 #ade4 ,photographic prop]ties ( ,salts ( ,silv]1 #ah2 ( ,iodide ( ,silv] ^u ,collodion1 #gd4 ,photographic rese>*es by ! ,au?or1 #adj4 ,photography1 hi/orical sket* (1 #f2 ! t]m expla9$1 #fa4 ,portrait l5ses1 !ory ( _! con/ruction1 #ei2 rules = _! use1 #bbg2 mode ( f9d+ *emical focus1 #bbi4 ,portraits1 drap]y =1 #ff2 directions = tak+1 #bbj2 ! position ( ! ,cam]a1 & o!r po9ts ( importance1 #bbh2 ! "t ( exposure1 #bba4 ,positive pr9t+1 on ,album9iz$ pap]1 =mul =1 #bda2 on pla9 pap]1 =mul =1 #bde2 on ,ammonio-,nitrate pap]1 =mula =1 #bdf1 #beh2 by developm5t1 =mul =1 #bei2 manipulatory details ( pr9t+1 fix+1 ton+1 wa%+1 & m\nt+1 #bea2 process ( ton+ by ,sel d'or1 !ory (1 #acd2 practice (1 #bfg2 reasons = ! want ( correspond5ce betwe5 diff]5t =mul1 #beg2 use ( ,*loride ( ,gold 9 ton+1 #acb1 #bga2 !ory ( ! prep>ation ( ! s5sitive pap] = ,positives1 #abb2 !ory ( ! process ( fix+1 #abi2 ( ton+ by ,gold1 #acb2 ! ,au?or's rese>*es1 #adj2 rationale ( ! pr9t+ process1 #abj2 composition ( ! image1 #adj2 fad+ ( ,positive pr9ts1 #afj2 de/ructive action ( ,sulphur on1 #ade2 ( oxidiz+ ag5ts on1 #adh2 ( ,*lor9e1 acids1 boil+ wat]1 etc41 on1 #aea2 ( combu/ion ( coal-gas on1 #aec2 effect ( damp air on1 #aec2 !ory ( mode ( wa%+ ,positives1 #afb2 comp>ative p]man5cy ( pr9ts1 #aff2 mode ( te/+ p]man5cy1 #afi4 ,positives1 def9ition (1 #ajf2 ,collodion ,positives1 !ory ( production (1 #ajh2 =mul = solutions =1 #bja2 developm5t (1 #aaa1 #bba2 ,collodion & ,nitrate ,ba? be/ adapt$ =1 #aji2 mode ( :it5+ by ,bi*loride ( ,m]cury1 #aab2 solution = :it5+1 #bjg2 mode ( back+ up1 #bbf2 spots & m>k+s on1 #bhd2 mode ( pr9t+ ,positives on ,collodion1 #bgb4 ,positives1 enl>g$1 mode ( pr9t+1 #bgb4 ,practice ( ,collodion process1 #ahc4 ,pres]vative processes = ,collodion plates1 #bhi4 ,pr9t+1 ,photographic1 !ory (1 #abj2 practical details (1 #bdj4 ,prism1 refraction ( light by1 #ea2 diagram ( =mation ( spectrum by1 #dg2 expla9$1 #ed4 ,prismatic spectrum1 #dg1 #fa4 ,protonitrate ( ,iron1 prep>ation (1 #bjf2 a feeble develop] :5 free f excess ( ,sulphate ( ,iron1 #ih2 !ory ( its mode ( action1 & rules = its use1 #aab2 _c be prep>$ 9 quantity by add+ ,nitrate ( ,pota% to ,sulphate ( ,iron1 #cad2 sometimes requires ! addition ( ,nitrate ( ,silv]1 #bjf4 ,protosulphate ( ,iron1 its prep>ation & prop]ties1 #bi2 its *>act]i/ics z a develop] = ,collodion ,positives1 #aaa2 n well adapt$ = develop+ ,collodion ,negatives1 #aag2 prep>ation ( ! solution = ,positives1 #bje2 mode ( apply+ x to ! plate1 #bba2 to remove iron /a9s on glass1 #bae4 ,pyrogallic ,acid1 its prep>ation & prop]ties1 #bh2 solution = develop+ glass ,positives1 #bje2 = ,negatives1 #baa2 _c be us$ )\t ,acetic ,acid1 #aje2 less adapt$ = develop+ pap] pictures1 #agh2 requires addition ( ,nitric ,acid :5 us$ = ,positives1 #aaa2 sup]ior to ,sulphate ( ,iron = develop+ ,negatives1 #aag1 #add2 mode ( obviat+ ! br[n discoloration ( develop+ solutions1 #bab4 ,pyroxyl9e1 its nature & prop]ties1 #ge2 prep>ation (1 by ,mr4 ,had['s =mula1 #ahf2 by a rule-(-?umb mixture ( ! acids1 #ahh2 by ! ,oil ( ,vitriol & ,nitre process1 #aij2 details ( imm]s+1 wa%+1 & dry+1 #aia2 ! glut9\s v>iety produc$ by cold acids1 #hc2 recapitulation ( ! effects ( v>y+ ! /r5g? ( ! acid mixture1 #aic2 spontane\s decomposition ( ,pyroxyl9e1 #aff4 ,r$uction ( metallic oxides by develop]s1 !ory (1 #bf2 ( ,silv] salts by develop]s1 !ory (1 #cj2 practical details ( r$uc+ ,silv] comp\nds to metallic /ate1 #cgb4 ,salts nature (1 #caj4 ,salts ( ,silv]1 _! prep>ation & prop]ties1 #ab2 _! ,photographic action1 #ah2 !ory ( _! r$uction by develop]1 #cj2 directions = obta9+ metal f1 #cgb4 ,sel d'or1 ton+ process by1 its !ory1 #acd2 its practical details1 #bfg2 its advantages1 #bga2 gives p]man5t pr9ts1 #afg4 ,s5sitiv5ess1 t]m expla9$1 #ib2 conditions fav\rable to1 #ig4 ,s5sitiv5ess ( ,collodion film1 causes influ5c+1 #ib2 sup]ior s5sitiv5ess p>tially expla9$1 #gd2 pres]vation ( s5sitive film1 #bhh4 ,s5sitive pap]1 !ory ( prep>ation (1 #bb1 #abb2 its d>k5+ by light describ$1 #abc2 prep>ation ( ,album9iz$ pap]1 #bda2 ( pla9 pap]1 #bde2 ( ,ammonio-,nitrate pap]1 #bdf1 #beh2 ( pap] = ,negative processes1 #bei2 causes :i* affect ! s5sitiv5ess ( ,positive pap]1 #abc2 :i* alt] ! col\r ( ! image1 #abf2 spots & m>k+s on1 #bhe2 a l>ge excess ( ,nitrate ( ,silv] ess5tial1 #abd2 ! pap] %\ld n be kept too long1 #acj1 #bhf4 ,s]um ( ,milk1 prep>ation (1 #bfb1 #cee2 us$ 9 ,negative pr9t+ process1 #bfb4 ,%adbolt1 ,mr41 8 ,honey keep+ process1 #bhi2 employs artificial light 9 ,micro-,photography1 #bcg4 ,silv]1 prop]ties (1 #cfb2 e/imation (1 9 ,nitrate ,ba?s1 #cga2 recov]y f wa/e solutions1 #cgb2 r$uction f ,*loride1 #cgd2 /a9s1 removal (1 #cgg4 ,size1 mode ( remov+1 f pap] ,positives1 #bee4 ,sol> spectrum1 #dg1 #fa4 ,soluble pap]4 ,see ,pyroxyl9e4 ,specific gravity ( liquids1 mode ( f9d+1 #cge4 ,sph]ical ab]ration1 #ef4 ,spirits ( ,w9e1 prep>ation & prop]ties1 #ccj2 n always suffici5tly /rong = ,collodion1 #hd2 mode ( rectify+1 #aif2 sometimes contam9at$ )1 fusel oil1 #if4 ,spots on ,collodion plates1 #bgi2 on pap] ,positives1 #bhe2 on pr9ts obta9$ by developm5t1 #bff2 on pres]v$ ,collodion plates1 #bic4 ,/a9s1 ,silv]1 removal (1 #cgg4 ,/]eoscope1 inv5tion (1 #fg2 !ory (1 #fh2 ,:eat/one's1 #fi2 ,brew/]'s1 #gj4 ,/]eoscopic ,photographs1 rules = tak+1 #ga2 practical details (1 #bcb4 ,/ops1 !ory ( use (1 #eg2 simple mode ( mak+1 #bbh2 position ( ! /op (t5 important1 #bcj4 ,/r5g? ( acids1 tables (1 #cgh4 ,sub*loride ( ,silv]1 its prep>ation & prop]ties1 #ae2 decompos$ by fix+ ag5ts1 #ada4 ,suboxide ( ,silv]1 its prop]ties1 #ah2 =ms comp\nds ) organic matt]s4 ,citric ,acid1 ,album51 etc41 #ba4 ,sub/itution1 laws (1 expla9$1 #gh4 ,sulphate ( ,iron4 ,see ,protosulphate ( ,iron4 ,sulphate ( ,qu99e1 absorption ( *emical rays by1 #fe4 ,sulphuric ,acid1 table ( /r5g? (1 #cgh4 ,sutton1 ,mr41 !ory ( ,sel d'or ton+ process1 #acd2 practical details (1 #bfg2 ,negative pr9t+ process1 #bfb2 prep>ation ( ,s]um ( ,milk =1 #cee4 ,symbols1 use (1 #cah4 ,syrup$ ,collodion film1 #bhi4 ,talbot1 ,mr41 8 discov]ies1 #i2 !ory ( ,calotype process1 #agf4 ,taup5ot1 ,m41 8 ,collodio-,album5 process1 #aha2 practical details (1 #bid4 ,temp]ature1 its effect ^u developm5t ( ,collodion film1 #ajb2 ^u fogg+1 #aje2 ^u keep+ ,collodion1 #baj2 ^u action ( fix+ ,ba? = pap] ,positives1 #acj2 ^u ,hypo ton+ ,ba?1 #acf4 ,te/-pap]s1 use (1 #cgf4 ,ton+ ,ba? = ,positives1 ) ,sel d'or1 #acd1 #bfg2 ) ,hyposulphite & ,gold1 see ,fix+ & ,ton+ ,ba?2 ) ,*loride ( ,iron & ,hyposulphite1 #afj4 ,ton+ ( ,positives1 t]m def9$1 #aba2 may injure ! /ability ( ! pro(1 #aed2 po9ts to be kept 9 view to avoid fad+1 #afg2 manipulatory details (1 #bec2 by ,sel d'or1 #bfg4 ,transp>5cies1 mode ( pr9t+1 #bgc4 ,v>ni%es = ,collodion ,photographs1 #bbf4 ,view ,l5ses1 directions = us+1 #bcj4 ,vocabul>y ( ,photographic *emicals1 #cbg4 ,wa%+ ,positive pr9ts1 rules =1 #afb2 details (1 #bee4 ,wax$ pap] process1 !ory (1 #agh4 ,weights & ,measures1 table (1 #cgi4 ,,pr9t$ ,,by ,,john ,,edw>d ,,taylor1 ,,little ,,que5 ,,/reet1 ,,l9coln',s ,,inn ,,fields4 99 99 99 99 99 ,transcrib] ,note ,m9or typos h be5 correct$4 ,images mov$ to prev5t splitt+ p>agraphs4