forty centuries of ink- 第24部分

owing　to　the　slow　blackening　of　the　gallic　acid　ink；

and　a　little　tannin　gives　initial　blackening　and　body；

while　it　is　absolutely　necessary　for　copying　ink。

Initial　blackness　can　also　be　ensured　by　oxidizing

21　per　cent　of　the　ferrous…sulphate　without　adding

the　extra　acid　necessary　to　the　formation　of　a　ferric

salt。



The　concluding　portion　of　his　research　is　devoted

to　the　influence　of　sugar　upon　the　permanence　of　ink；

and　the　results　of　the　experiments　are　summed　up　in

the　following　sentences：　〃It　would　be　injurious　to

add　3　per　cent　of　sugar　to　a　tan　in　ink；　while　from

4　to　10　per　cent　would　be　quite　allowable。　Most

copying　inks　contain　about　3。5　per　cent　of　sugar

not　far　from　the　critical　amount。　With　gallic　acid

more　than　3　per　cent　of　sugar　hardly　varies　the　precipitate；

but　the　importance　of　this　point　is　somewhat

diminished　by　the　fact　that　the　presence　of　sugar　is

by　no　means　necessary　in　a　writing　ink。　Dextrin　is

a　much　superior　substance　to　use。　Curiously　this

body　rapidly　precipitates　a　tannin　ink；　hence　it　is

useless　for　copying　ink；　but　for　the　gallic　ink　it　is　an

excellent　thickener。〃



Chen…Ki…Souen；　〃Lencre　de　China；〃　by　Maurice　Jametel；

appeared　in　Paris　in　1882；　but　as　the　title　indicates；

it　is　the　old　〃Indian〃　or　Chinese　ink　that　is　discussed。



Schluttig　and　Neumann　in　1890　issued　their

Edition　Dresden　on　the　subject　of　〃Iron　and　Gall

inks。〃　In　this　valuable　work　is　to　be　found　the

formula　which　has　been　generally　adopted　as　the

standard　where　one　is　used　for　tanno…gallate　of　iron　ink。



The　investigations　of　other　scientific　men　like　Lepowitz；

Booth；　Desormeaux；　Chevreuse；　Irvine；　Traille；

Bottger；　Riffault；　Precht；　Nicholes；　Runge；　Gobert；

Penny；　Arnold；　Thomson　（Lord　Kelvin）；　Davids；　Kindt；

Ure；　Wislar　and　many　more　who　have　dealt　with　the

chemistry　of　inks；　present　to　us　some　testimony　during

a　considerable　portion　of　the　nineteenth　century

of　the　efforts　made　to　secure　a　good　ink。









CHAPTER　XIV。



CLASSIFICATIONS　OF　INK。



INK　USED　BY　US　HAS　NOTHING　IN　COMMON　WITH　THAT

OF　THE　ANCIENTSMANUFACTURERS　OF　THE　PRESENT

TIME　HAVE　LARGELY　UTILIZED　FORMULAS　EMPLOYED

IN　PAST　CENTURIESTHE　COMMON　ACCEPTATION　OF

THE　TERM　INKSEVEN　DIFFERENT　CLASSES　OF　INKS

AND　THEIR　COMPOSITION　BRIEFLY　TOLDFAILURE　OF

EFFORTS　TO　SECURE　A　REAL　SAFETY　INK。



THE　inks　used　by　us　have　nothing　in　common　with

those　of　the　ancients　except　the　color　and　gum；　and

mighty　little　of　that。



Those　of　the　〃gall〃　class　employed　in　the　fourteenth；

fifteenth；　sixteenth；　seventeenth　and　eighteenth

centuries；　some　formulas　of　which　are　utilized

by　the　manufacturers　of　ink　in　our　own　time；　consisted

generally　in　combination；　infusions　of　nut…galls；　sulphate

of　copper　or　iron；　or　both；　and　fish…glue　or　gum；

slightly　acidulated。　The　frequent　introduction　of　the

so…called　〃added〃　color　into　these　inks；　time　has　shown

to　have　been　a　grave　mistake。



The　common　acceptation　of　the　term　〃ink〃　may　be

said　to　characterize　an　immense　number　of　fluid　compounds；

the　function　of　which　in　connection　with　a

marking　instrument　is　to　delineate　conventional　signs；

characters　and　letters　as　put　together　and　commonly

called　writing；　on　paper　or　like　substances。



To　classify　them　would　be　impossible；　but　black

writing　ink；　chemical　writing　fluid；　colored　writing

ink；　copying　ink；　India　ink；　secret　or　sympathetic　ink；

and　indelible　ink　make　seven　classes；　the　others　may

be　denominated　under　the　head　of　miscellaneous　inks；

and　of　them　all；　there　is　no　single　ink　answering　every

requirement　and　few　answer　at　all　times　the　same　requirements。

Ink　may　be　either　a　clear　solution　of　any

coloring　matter　or　of　coloring　matter　held　in　suspension。

It　is　a　remarkable　fact　that　although　most　inks

are　chemical　compositions　and　many　times　made　after

the　same　formula；　identical　results　cannot　always　be

calculated　or　obtained。　This　is　more　particularly　to　be

noted　in　the　case　of　black　writing　inks　otherwise

known　as　the　tanno…gallate　of　iron　inks　＇gallic　and　gallotanic

acid　obtained　from　nut…galls；　sulphate　of　iron；

（green　copperas）　and　some　gummy　vehicle＇。



The　variations　would　appear　to　be　largely　due　to　the

difference　in　quality　of　the　gall…nuts；　treatment；　and

temperature　of　the　atmosphere；　perhaps；　however；　not

so　much　to…day　as　it　was　ten　or　twenty　years　ago；

when　to　make　ink　of　this　character　boiling　processes

were　employed。　Most　of　them　as　already　stated　are

now　〃cold〃　made。



Inks　of　this　class　consist　of　a　finely　divided　insoluble

precipitate　suspended　in　water　by　the　use　of　gum　and

possessing　a　slight　acidity。



The　requisites　of　a　good　black　writing　ink　or

black　writing　fluid　require　it　to　flow　readily　from

the　pen；　to　indicate　in　a　short　time　a　black　color

and　to　penetrate　the　paper　to　an　appreciable

degree；　and　more　important　than　all　the　rest；　to　be　of

great　durability。　When　kept　in　a　closed　vessel　no

sediment　of　any　account　should　be　precipitated；　although

such　will　be　the　case　in　open　ink…wells；　and

this　the　quicker　the　more　the　air　is　permitted　to　get

to　it。　If　it　is　to　be　used　for　record　or　documentary

purposes　it　must　not　be　altogether　obliterated　if　brought

into　contact　with　water　or　alcohol；　and　should　depend

for　permanency　on　its　chemical　and　not　on　its　pigmentary

qualities。



The　second　class；　called　for　distinction　〃chemical

writing　fluids；〃　possesses　the　same　essential　ingredients

to　be　found　in　class　one；　but　much　less　in

quantity　and　with　some　〃added〃　colored　substance

which　I　shall　term　〃loading；〃　for　its　real　purpose　is　to

cheapen　the　cost　of　production　and　not　altogether　as

some　manufacturers　state　〃simply　to　give　them　an

agreeable　color。〃



Previous　to　the　discovery　of　the　soluble　anilines；

logwood；　indigo；　madder；　orchil　and　other　dyeing

materials　were　used　for　a　period　of　some　eighty　years

and　vanadium　for　some　twenty　years　（very　costly

at　that　time）；　for　this　purpose；　but　since　1874；　and

with　frequent　changes　as　the　newer　aniline　compounds

were　invented；　these　by…products　of　coal…tar；　as　well　as

logwood；　etc。；　have　been　and　are　to…day　employed　for

〃loading；〃　or　as　the　manufacturer　expresses；　it　〃added

color。〃　The　chemical　writing　fluids　as　now　prepared；

yield　when　first　written　a　blue　or　green　color　with　a

tendency　to　change　to　black　afterwards。　They　are

not　as　permanent　as　those　of　the　first　class。



Another　black　ink　not　durable；　however；　is　〃logwood；〃

its　extract　is　combined　with　a　little　chromate

of　potassium　and　boiled　together　in　water。　It　possesses

its　own　〃gum〃　and　contains　some　tannin。　In

combination　with　alum　and　water；　it　forms　a　dark

purple　ink。



The　colored　writing　inks；　of　which　〃red〃　is　the

more　important；　are　in　great　number　and　with　hardly

an　exception　at　the　present　time；　manufactured　by

adding　water　and　water…glass　to　a　soluble　aniline　red

color。　Cochineal　which　was　used　for　red　ink　formerly

is　now　almost　obsolete。　Nigrosine；　one　of　the　best

known　of　them；　is　much　used　as　a　cheap　〃black〃　ink；

but　as　it　is　blue　black　and　never　becomes　black；　it

really　belongs　to　the　family　of　〃colored〃　writing

inks。　They　possess　an　undeserved　popularity　for　they

flow　freely　from　the　pen　which　they　do　not　corrode；

nor　do　they　thicken　or　spoil　in　the　inkwell；　they　are

however　very　〃fugitive〃　in　character　and　should　not

be　employed　for　record；　legal；　monetary　or　other

documentary　purposes。　The　indigo　and　prussian　blue

inks　are　well　known；　the　former　under　certain　conditions

a　very　permanent　ink；　the　latter　soon　disintegrating。



Copying　inks　are　of　two　kinds；　one　dependent　on

the　addition　of　glycerine；　sugar；　glucose　or　like　compounds

to　the　black　writing　inks　or　chemical　writing

fluids　heretofore　mentioned；　which　are　thereby　kept

in　a　moist　offsetting　condition；　the　other　due　to　the

solubility　of　the　pigmentary　color　with　water；　such　as

the　aniline　inks　which　are　given　more　body　than

those　for　ordinary　purposesand　the　logwoods　in

which　the　pigment　is　developed　and　given　copying

qualities　by　chemicals；　and　hence　becomes　responsive

to　the　application　of　a　sheet　of　paper　dampened　with

water。　Copying　ink　should　never　be　used　for

〃record〃　purposes　as　it　is　affected　by　changes　of　the

temperature。



India　ink；　sometimes　called　China　ink；　or　as　formerly

known　by　the　ancients　and　in　classical　and　later　times

〃Indian　ink；〃　is　now　used　more　for　drawing　and　engrossing

than　it　is　for　commercial　purposes。　It　belongs

to　the　〃carbon〃　class　and　in　some　form　was

the　first　one　used　in　the　very　earliest　times。　In

China　it　is　applied　with　a　brush　or　pith　of　some　reed

to　the　〃rice〃　paper　also　there　manufactured。　It　is

easily　washed　away　unless　bichromate　of　ammonium

or　potassium　in　minute　quantities　be　added　to　it；　and

then　if　the　paper　on　which　it　appears　be　exposed　for　a

short　time　to　the　action　of　the　actinic　rays　of　sunlight；

this　gummy　compound　will　be　rendered　insoluble　and

cannot　be　removed　with　any　fluid；　chemical　or　otherwise。

It　possesses　also　great　advantages　in　drawing；

since　it　acts　as　a　paint；　and　will　give　any　degree　of

blackness　according　to　the　quantity　of　water　mixed　with　it。



Secret　or　sympathetic　inks　are　invisible　until　the

writing　is　subjected　to　a　subsequent　operation；　such

as　warming　or　exposing　to　sunlight。　To　further　aid

the　object　in　view；　the　paper　may　be　first　steeped　in

a　liquid　and　the　writing　only　made　visible　by　using

another　liquid　which　has　some　chemical　affinity　with

the　previous　one。　The　number　of　this　kind　were　but

few　but　have　multiplied　as　chemistry　progressed。

The　ancients　were　acquainted　with　several　modes。

Ovid　indiscreetly　advises　the　Roman　wives　and　maidens

if　they　intend　to　make　their　correspondence　unreadable

to　the　wrong　persons　to　write　with　new　milk；

which　when　dried　may　be　rendered　visible　by　rubbing

ashes　upo