forty centuries of ink-第41章

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〃2d。　The　applications　made　to　the　surface　of

a　sheet　of　paper；　with　a　view　of　covering　it　again

at　certain　parts　with　a　fine　layer　of　gum；　gelatine；

starch　or　flour　paste；　or　in　other　places　to　cause

other　sheets　of　paper　to　adhere；　may　be　recognized

not　only　by　the　reflection　of　light　falling　upon　the

paper　inclined　at　a　certain　degree　of　obliquity；　and

by　the　transmission　of　light　through　the　paper；

but　also　by　the　varying　action　which　the　vapor　of

iodine　exerts　on　the　surface　which　is　not　homogeneous。

Papers　containing　starch　and　resin　are

more　powerfully　acted　upon　by　this　vapor　than

papers　of　a　less　complex　composition。　Both　in

the　parts　covered　with　starch；　or　paste　flour；　are

colored　in　a　few　minutes　of　a　violet　blue；　but

with　starched　papers　alone　a　more　intense　coloration

is　manifest　on　the　places　covered　again　with　a

thin　layer　of　gum　arabic；　size　or　gelatine。　By

looking；　then；　on　the　surface　of　the　paper；　held

somewhat　obliquely　to　incidental　light；　we　distinguish

clearly；　by　their　different　aspects；　the　parts

on　which　these　various　substances　have　been

applied。　The　vapor　of　iodine；　in　condensing　at

the　ordinary　temperature　on　the　surface　of　the

papers　to　which　any　kind　of　size　has　been　applied

in　various　places；　produces　differences　which　are

most　commonly　well　recognized　by　the　greater　or

less　transparence　of　the　paste　of　the　paper。



3d。　The　heterogeneousness　of　the　pulp　of　the

various　papers　of　commerce；　and　the　nature　of

the　size　with　which　they　are　penetrated；　cause

differences；　either　in　the　coloration　which　the　surface

of　these　papers　takes　when　exposed　to　the

vapor　of　iodine；　or　in　the　tint　which　is　manifested

in　the　portions　of　the　size　deposited　in　certain

portions　of　that　surface；　thus；　papers　with　starched

pulp　generally　turn　brown；　or　blue；　according　to

the　amount　of　water　that　remains　in　their　interstices；

other　papers　turn　yellow　only　under　the

influence　of　the　vapor　of　iodine；　and　the　parts

which　have　received　superficially　a　layer　of　another

agglutinative　body　resist　this　action　for　a　certain

time；　and　are　distinguished　from　the　parts　of　the

paper　which　are　not　covered　with　it。〃



My　own　investigations　confirm　to　a　great　extent

the　value　of　these　experiments　and　the　accuracy　of

the　deductions；　in　so　far　as　they　relate　to　〃linen〃

paper；　but　they　do　not　always　obtain　when　made　in

connection　with　paper　of　inferior　grades。



It　is　also　true　that　dry　paper　is　affected　differently

under　the　influence　of　the　vapor　of　iodine；　as　would

be　paper　which　had　been　moistened　and　then　dried；

but　the　part　which　had　been　moist　assumes　the　color

of　blue…violet；　while　unaltered　paper　assumes　a　yellow…

brown　color。　Even　when　the　paper　thus　treated　is

moistened　all　over　with　water；　there　will　be　a　difference；

for　those　parts　which　had　been　before　moistened；

will　appear　a　dark　violet…blue；　while　the　other　parts

will　show　a　plain　blue　coloration。



In　cases　where　pencil　writing　has　been　removed

with　a　soft　rubber　or　fresh　bread；　the　parts　thus

erased　will　assume；　when　subjected　to　iodine　fumes；　a

brown　color　trending　towards　violet　and　much　darker

than　the　undisturbed　portions　of　the　paper。　Lines

impressed　upon　paper　with　a　〃stylus；〃　a　glass　or

ordinary　dry　pen；　can　be　made　visible　by　the　fumes　of

iodine；　the　lines　showing　with　a　stronger　coloration

than　the　surrounding　paper。







CHAPTER　XX。




FUGITIVE　INK。



SOME　OBSERVATIONS　ABOUT　〃ADDED〃　COLOR　TO　INK

INVENTION　OF　COAL　TAR　COLORSCHRONOLOGICAL　HISTORY

OF　THE　〃ANILINES〃　EMPLOYED　AS　INKOTHER

SUBSTANCES　USED　FOR　THE　SAME　PURPOSE。



THE　term　〃added　color；〃　as　applied　to　ink；　is　the

popular　phraseology　for　a　multitude　of　materials

which　have　been　more　or　less　utilized　for　a　period　of

centuries；　in　adulterating　and　coloring　ink。　In　olden

times　they　were　introduced　into　ink　with　an　honest

belief　that　it　would　also　improve　and　ensure　its　lasting

qualities；　but　latterly　more　often　to　cheapen　the

cost　of　its　manufacture。　Reference　has　been　made

to　a　large　variety　of　these　substances　used　for　this

purpose　and　the　story　told　of　the　effect　of　the　test　of

time　upon　them　as　indicative　of　their　supposed　value。

Attention　has　also　been　directed　to　the　discovery

during　the　nineteenth　century　of　the　colors　which

owe　their　origin　to　by…products　of　coal　tar。



Generically　these　colors　are　classified　as　〃anilines。〃

They　have　worked　a　revolution　in　all　the　arts　in

which　colors　are　used。　Employed　without　a　mordant；

with　few　exceptions；　they　are　measurably　affected　by

both　light；　heat；　moisture；　or　other　changes　and　as

made　into　inks　are　never　permanent。　Hence　they

should　not　be　used　for　records；　because　if　obliterated

from　any　cause　whatever；　there　are　no　known　means

to　render　them　again　legible。



The　origin　and　history　of　the　〃anilines〃　are

known。　Viewed　from　an　ink　standpoint　they　are　of

vast　interest。　So　extended　in　number　are　the　〃anilines〃

（they　run　into　the　thousands）　that　they　include

every　shade　of　black　and　all　possible　tints　or　hues　of

the　colors　of　the　rainbow。



The　chronological　history　of　such　of　these　artificial

colors　which　appertain　to　ink　or　its　manufacture　is

important　as　locating　the　dates　of　their　invention

and　commercial　use。



The　first　discovery　of　〃aniline〃　is　credited　to

Helot　in　1750。　In　1825　Faraday　in　rectifying　naphtha

discovered　benzole；　which　by　the　action　of　strong

nitric　acid　be　converted　into　nitro…benzole；　and　this

latter；　when　agitated　with　water；　acetic　acid　and　iron

filings　produced　aniline。　Unverdorben　in　1826　discovered

an　analogous　material　in　products　obtained

by　the　destructive　distillation　of　indigo。　Runge　in

1834　claims　to　have　detected　it　in　coal　tar　and　called

it　kyanol；　which　after　oxidation　became　an　insoluble

black　pigment　and　known　as　aniline　black。　It　could

not；　however；　be　used　as　an　ink。　Zinan　in　1840；

experimenting　along　the　same　lines；　produced　another

compound　terming　it　benzidam。　Fritsche　in　the　same

year　by　the　distillation　of　indigo　with　caustic　potash

developed　a　product　which　he　also　called　aniline；　the

name　being　derived　from　the　Portuguese　word　anil；

meaning　indigo。　Shortly　afterwards　A。　W。　Hoffman

established　the　identity　of　these　substances。



Aniline　when　pure　is　a　colorless　liquid；　possessing

a　rather　ammoniacal　odor。　It　soon　becomes　yellow

and　yellow…brown　under　the　influence　of　light　and　air。

It　does　not　affect　litmus　paper。



In　1856　Perkins　accidentally　discovered　the　violet

dye　called　mauve；　which　acquired　considerable　commercial

importance　besides　its　utility　for　ink　purposes。



Nicholson　in　1862　succeeded　in　producing　the　first

of　the　soluble　blue　anilines。



The　discovery　of　induline；　one　of　the　modifications

of　aniline　black；　was　made　known　in　1864。



Nigrosine；　produced　by　the　action　of　concentrated

sulphuric　acid　on　the　insoluble　indulines；　was　discovered

in　1868。



The　soluble　indulines　and　nigrosines　differentiate　in

appearance；　the　first　a　bronzy　powder　and　the　latter　a

black　lustrous　powder。　When　made　into　ink　they

possess　about　equal　color　values。



In　1870　the　German　chemists；　Graebe　and　Liebermann；

announced　that　they　had　succeeded　in　producing

artificial　alizarin；the　coloring　matter　of　the

madder　root。　Commercial　value　was　not　given　to

this　discovery　until　it　was　put　on　the　market　in　1873；

although　it　did　not　meet　all　the　requirements。



Springmuhl　in　1873　obtained　an　accessory　product

in　the　artificial　manufacture　of　alizarin　out　of　anthracene；

from　which　a　beautiful　blue　was　made；　superior

in　many　respect　to　the　aniline　blues。　It　differed　from

aniline　in　having　the　same　color　in　solution。　Alkalis

destroyed　the　color　but　acids　restored　it。　The　process

was　kept　a　secret　for　a　long　time。　This　product　was

originally　sold　as　high　as　1；500　for　a　single　pound。



Caro；　a　German　chemist；　invented　in　1