forty centuries of ink- 第21部分

Barbedor　illustrating　the　French　style；　Vignon；　Sellery

and　others；　for　the　Italian　hand；　and　Overbique　and

Smythers　for　the　German　text；　and　Ambrosius　Perlengh

and　Hugo；　with　a　few　more；　complete　the　list。









CHAPTER　XII。



STUDY　OF　INK。



LACK　OF　INTEREST　AS　TO　THE　COMPOSITION　OF　INK　DURING

PART　OF　THE　EIGHTEENTH　CENTURYTHE　CONDITIONS

WHICH　THEN　PREVAILED　NEARLY　THE　SAME　AS

THE　PRESENT　TIMECHEMISTRY　OF　INK　NOT　UNDERSTOOD

THIS　LACK　OF　INFORMATION　NOT　CONFINED　TO

ANY　PARTICULAR　COUNTRYLEWIS；　IN　1765；　BEGINS

A　SCIENTIFIC　INVESTIGATION　ON　THE　SUBJECT　OF　INKS

THE　RESULTS　AND　HIS　CONCLUSIONS　PUBLISHED　IN

1797THE　ROYAL　SOCIETY　OF　ENGLAND　IN　1787　RECEIVES

COMPLAINTS　ABOUT　THE　INFERIORITY　OF　INKS

ITS　SECRETARY　READS　A　PAPER　THE　SAME　YEARTHE

PAPER　CITED　IN　FULLDR。　BOSTOCK　IN　1830　COMMUNICATES

TO　THE　SOCIETY　OF　ARTS　WHAT　HE　ESTIMATES

TO　BE　THE　CAUSES　OF　IMPERFECTIONS　IN　INK

ACTION　OF　THE　FRENCH　ACADEMY　OF　SCIENCES

COMPLICATIONS　SURROUNDING　THE　MANUFACTURE　OF　INK

ONLY　THIRTY…FIVE　YEARS　AGO。



THE　increasing　demands　for　ink；　and　the　lack　of　interest

as　to　its　composition　during　the　eighteenth

century；　if　viewed　in　the　same　lights　which　prevail　in

our　own　times；　permitted　the　general　manufacture　of

cheap　grades　of　ink　which　possessed　no　very　lasting

qualities。　The　chemistry　of　Inks　was　not　fully　understood；

indeed　we　find　Professer　Turner　of　the　College

of　Edinburgh　declaring　in　1827：



〃Gallic　acid　was　discovered　by　Scheele　in　1786；

and　exists　ready　formed　in　the　bark　of　many　trees；

and　in　gall…nuts。　It　is　always　associated　with

tannin；　a　substance　to　which　it　is　allied　in　a　manner

hitherto　unexplained。　It　is　distinguished　from

tannin　by　causing　no　precipitate　in　a　solution　of

gelatine。　With　a　salt　of　iron　it　forms　a　dark　blue

coloured　compound；　which　is　the　basis　of　ink。　The

finest　colour　is　procured　when　the　peroxide　and

protoxide　of　iron　are　mixed　together。　This　character

distinguishes　gallic　acid　from　every　other　substance

excepting　tannin。〃



The　general　lack　of　information　or　knowledge　respecting

ink　chemistry　or　its　time…phenomena　was　not

confined　to　any　particular　country；　and　it　does　not

appear　that　any　general　or　specific　attention　was

scientifically　directed　to　it　until　1765；　when　William

Lewis；　F。　R。　S。；　an　English　chemist；　publicly　announced

that　he　proposed　to　investigate　the　subject。

His　experimentations　covered　a　period　of　many　years

and　their　results　and　his　theories　as　to　the　phenomena

of　inks　were　published　in　1797。　The　most　valuable

of　his　conclusions　were　that　an　excess　of　iron　salt　in

the　ink　is　detrimental　to　color　permanence　（such　ink

becoming　brown　on　exposure）　and　also　that　acetic

acid　in　the　menstruum　provides　an　ink　of　greater

body　and　blackness　than　sulphuric　acid　does　（a　circumstance

due　to　the　smaller　resistance　of　acetic　acid

to　the　formation　of　iron　gallo…tannate）。　Many　of　his

other　observations　were　later　shown　to　have　been

erroneous。　Dr。　Lewis　was　the　first　to　advocate　log…

wood　as　a　tinctorial　agent　in　connection　with　iron　and

gall　compositions。



Ribaucourt；　a　French　ink　maker；　in　1798　determined

that　an　excess　of　galls　is　quite　as　injurious　to

the　permanence　of　ink　as　an　excess　of　iron。



Pending　the　completion　of　the　researches　of　Lewis；

the　Royal　Society　of　England；　affected　by　complaints

from　all　quarters　relative　to　the　inferiority　of　inks　as

compared　with　those　of　earlier　times；　brought　the

subject　to　the　attention　of　many　of　its　members　for

discussion　and　advice。　Its　secretary；　Charles　Blagden；

M。　D。；　read　a　paper　before　the　society；　June　28；　1787；

which　was　published　in　the　〃Philosophical　Transactions〃

and　widely　circulated。　It　is　so　interesting　that

copious　extracts　are　given：



〃In　a　conversation　some　time　ago　with　my　friend

Thomas　Astle；　Esq。；　F。　R。　S。　and　A。　S。；　relative

to　the　legibility　of　ancient　MSS。　a　question　arose；

whether　the　inks　in　use　eight　or　ten　centuries　ago；

which　are　often　found　to　have　preserved　their　colour

remarkably　well；　were　made　of　different　materials

from　those　employed　in　later　times；　of　which　many

are　already　become　so　pale　as　scarcely　to　be　read。

With　a　view　to　the　decision　of　this　question；　Mr。

Astle　obligingly　furnished　me　with　several　MSS。；

on　parchment　and　vellum；　from　the　ninth　to　the

fifteenth　centuries　inclusively；　some　of　which　were

still　black；　and　others　of　different　shades　of　colour；

from　a　deep　yellowish　brown　to　a　very　pale　yellow；

in　some　parts　so　faint　as　to　be　scarcely　visible。　On

all　of　these　I　made　experiments　with　the　chemical

re…agents　which　appeared　to　me　best　adapted　to

the　purpose；　namely；　alkalis　both　simple　and　phlogisticated；

the　mineral　acids；　and　infusions　of　galls。



〃It　would　be　tedious　and　superfluous　to　enter　into

a　detail　of　the　particular　experiments；　as　all　of

them；　one　instance　only　excepted；　agreed　in　the

general　result；　to　shew　that　the　ink　employed

anciently；　as　far　as　the　above…mentioned　MSS。

extended；　was　of　the　same　nature　as　the　present；

for　the　letters　turned　of　a　reddish　or　yellow　brown

with　alkalis；　became　pale；　and　were　at　length

obliterated；　with　the　dilute　mineral　acids；　and　the

drop　of　acid　liquor　which　had　extracted　a　letter；

changed　to　a　deep　blue　or　green　on　the　addition　of

a　drop　of　phlogisticated　alkali；　moreover；　the　letters

acquired　a　deeper　tinge　with　the　infusion　of

galls；　in　some　cases　more；　in　others　less。　Hence

it　is　evident；　that　one　of　the　ingredients　was　iron；

which　there　is　no　reason　to　doubt　was　joined　with

the　vitriolic　acid；　and　the　colour　of　the　more　perfect

MSS。　which　in　some　was　deep　black；　and　in　others

purplish　black；　together　with　the　restitution　of　that

colour；　in　those　which　had　lost　it；　by　the　infusion

of　galls；　sufficiently　proved　that　another　of　the　ingredients

was　a　stringent　matter；　which　from　history

appears　to　be　that　of　galls。　No　trace　of　a　black

pigment　of　any　sort　was　discovered；　the　drop　of

acid　which　had　completely　extracted　a　letter；　appearing

of　an　uniform　pale　ferrugineous　color；　without

an　atom　of　black　powder；　or　other　extraneous

matter；　floating　in　it。



〃As　to　the　durability　of　the　more　ancient　inks；

it　seemed；　from　what　occurred　to　me　in　these　experiments；

to　depend　very　much　on　a　better　preparation

of　the　material　upon　which　the　writing　was

made；　namely；　the　parchment　or　vellum；　the　blackest

letters　being　those　which　had　sunk　into　it

deepest。　Some　degree　of　effervescence　was　commonly

to　be　perceived　when　the　acids　came　into

contact　with　the　surface　of　these　old　vellums。　I

was　led；　however；　to　suspect；　that　the　more　modern；

for　in　general　the　tinge　of　colour；　produced　by　the

phlogisticated　alkali　in　the　acid　laid　upon　them；

seemed　less　deep；　which；　however；　might　depend

in　part　upon　the　length　of　time　they　have　been

kept：　and　perhaps　more　gum　was　used　in　them；

or　possible　they　were　washed　over　with　some　kind

of　varnish；　though　not　such　as　gave　gloss。



〃One　of　the　specimens　sent　me　by　Mr。　Astle；

of　the　fifteenth　century；　and　the　letters　were　those

of　an　engrossing　hand；　angular；　without　any　FINE

strokes；　broad　and　very　black。　On　this　none　of

the　above…mentioned　re…agents　produced　any　considerable

effect；　most　of　them　seemed　to　make　the

letters　blacker；　probably　by　cleaning　the　surface；

and　the　acids；　after　having　been　rubbed　strongly　on

the　letters；　did　not　strike　any　deeper　tinge　with　the

phlogisticated　alkali。　Nothing　had　a　sensible　effect

toward　obliterating　these　letters　but　what　took　off

part　of　the　surface　of　the　vellum；　when　small　rolls；

as　of　a　dirty　matter；　were　to　be　perceived。　It　is

therefore　unquestionable；　that　no　iron　was　used　in

this　ink；　and　from　its　resistance　to　the　chemical

solvents；　as　well　as　a　certain　clotted　appearance　in

the　letters　when　examined　closely；　and　in　some

places　a　slight　degree　of　gloss；　I　have　little　doubt

but　they　were　formed　with　a　composition　of　a　black；

sooty　or　carbonaceous　powder　and　oil；　probably

something　like　our　present　printer's　ink；　and　am　not

without　suspicion　that　they　were　actually　printed

（a　subsequent　examination　of　a　larger　portion　of

this　supposed　MSS。　has　shown　that　it　is　really　a　part

of　a　very　ancient　printed　book）。



〃Whilst　I　was　considering　of　the　experiments

to　be　made；　in　order　to　ascertain　the　composition

of　ancient　inks；　it　occurred　to　me　that　perhaps　one

of　the　best　methods　of　restoring　legibility　to　decayed

writing　might　be　to　join　phlogisticated　alkali

with　the　remaining　calx　of　iron；　because；　as　the

quantity　of　precipitate　formed　by　these　two　substances

very　much　exceeds　that　of　the　iron　alone；

the　bulk　of　the　colouring　matter　would　thereby　be

greatly　augmented。　M。　Bergman　was　of　opinion

that　the　blue　precipitate　contains　only　between　a

fifth　and　a　sixth　part　of　its　weight　of　iron；　and

though　subsequent　experiments　tend　to　show　that；

in　some　cases　at　least；　the　proportion　of　iron　is

much　greater；　yet　upon　the　whole　it　is　certainly

true；　that　if　the　iron　left　by　the　stroke　of　a　pen

were　joined　to　the　colouring　matter　of　phlogisticated

alkali；　the　quantity　of　Prussian　blue　thence

resulting　would　be　much　greater　than　the　quantity

of　black　matter　originally　contained　in　the　ink

deposited　by　the　pen；　though　perhaps　the　body　of

colour　might　not　be　equally　augmented。　To　bring

the　idea　to　the　test；　I　made　a　few　experiments　as

follows：



〃The　phlogisticated　alkali　was　rubbed　upon　the

bare　writing　in　different　quantities；　but　in　general

with　little　effect。　In　a　few　instances；　however；　it

gave　a　bluish　tinge　to　the　letters；　and　increased

their　intensity；　probably　where　something　of　an

acid　nature　had　contributed　to　the　diminution　of

their　colour。



〃Reflecting　that　when　phlogisticated　alkali　forms

its　blue　precipitate　with　iron　the　metal　is　first　usually

dissolved　in　an　acid；　I　was　next　induced　to