76 
Observations on the Manufacture of writing Ink. 
tity of gumarabic. This is usually accounted for by the superior affinity of the 
gallic acid, which, combining with the iron, takes it from the sulphuric, and falls 
down. But it appears as if this were not the simple state of the facts ; for the 
sulphuric acid in ink is not so far disengaged as to act speedily upon fresh iron, or 
give other manifestations of its presence in an uncombined state. According to 
Peveux, the iron in ink is partly in the state of a gallate. 
M. Ribaucourt paid particular attention to the process for making black ink, 
and from his experiments he draws the following inferences. That log-wood is a 
useful iugredient in ink, because its colouring matter is disposed to unite with the 
oxyde of iron, and renders it not only of a very dark colour, but less capable of change 
from the action of acids, or of the air. Sulphate of copper, in a certain proportion, 
gives depth and firmness to the colour of the ink. Gumarabic or any other pure 
gum, is of service, by retarding the precipitation of the feculse ; by preventing the 
ink from spreading or sinking into the paper; and by affording it a kind of com- 
pact varnish or defence from the air when dry. Sugar appears to have some bad 
qualities, but is of use in giving a degree of fluidity to the ink. which permits the 
dose of gum to be enlarged beyond what the ink would bear without it Water is 
the best solvent. 
Lewis had supposed that the defects of ink arise chiefly from a want of colouring 
matter. But the theory grounded on the fact discovered by M. Ribaucourt requires, 
that none of the principles should be in excess. 
It is doubtful whether the principles of the galls be well extracted by macera- 
tion ; and it is certain, that inks made in this w ay flow pale from the pen, and are 
not of so deep a black as those wherein strong boiling is recurred to. 
From all the foregoing considerations M. R. gives these directions for the com- 
position of good ink : — 
Take eight ounces of Aleppo galls (in coarse powder) ; four ounces of Jog-wood 
(in thin chips); four ounces of sulphate of iron; three ounces of gumarabic (in 
powder) ; one ounce of sulphate of copper ; and one ounce of sugar candy. Boil 
the galls and logwood together in twelve pounds of water for one hour, or till half 
the liquor has evaporated Strain the decoction through a hair sieve or linen cloth, 
and then add the other ingredients. Stir the mixture till the whole is dissolved, 
more especially the gum; after Which, leave it to subside for twen tv- four hours- 
Then decant the ink, and preserve it in bottles of glass or stone ware, well corked. 
Many recommend, that the sulphate of iron should be calcined to whiteness. Mr. 
Desormeaux, jun. and ink manufacturer in Spittalfields, has given the following in 
the Philosophical Magazine, as the result of much experience : Boil four ounces of 
log-wood about an hour in six beer quarts of water, adding boiling water from time 
to time ; strain while hot ; and w'hen cold, add water enough to make the liquor 
five quarts. Into this put one pound avoirdnp. of blue galls coarsely bruised ; four 
ounces of sulphate of iron calcined to whiteness ; three otiuces of coarse brown 
sugar ; six ounces of gumarabic ; and one fourth of an ouuce of acetate of copper, 
triturated with a little of the decoction to a paste, and then thoroughly mixed with 
the rest. This is to be kept in a bottle uncorked about a fortnight, shaking it 
twice a day, after which it may be poured from the dregs, and corked up for use. 
Dr. Lewis uses vinegar for his menstruum ; and M. Ribaucourt has sulphate of 
copper among his ingredients. I have found an inconvenience from the use of either, 
which, though it does not relate to the goodness of the ink, is sufficiently great, in 
their practical exhibition, to forbid their use The acid of the vinegar acts so strong- 
ly upon the pen, that it very frequently requires mending ; and the sulphate of 
copper has a still more unpleasant effect on the penknife. It seldom happens when 
a pen requires mending, that the ink is wiped very perfectly from it ; and’often, 
when the nib only is to be taken off, it is done without wiping a t all ’ Whoever 
this is the ease, the ink immediately deposits a film of copper upon the knife and by 
superior elective attraction of the sulphuric acid , a correspondent portion of the edge 
ot the kmte is dissolved, and is, by this means, rendered incapable of outline till it 
has been again set upon the hone. cutting uu 
If a little sugar be added to ink, a copy of the writing may easily be taken off, 
by laying a sheet of thin unsized paper, damped with a sponge, “ the written Z- 
per, and passing lightly over it a flat iron very moderately heated. P 
. J . of °Dier colours may be made from a strong decoction of the imrredients used 
m dyeing, mixed with a little alum and gumarabic. For example a^tronc decoc- 
good°redTik W Thrae U n ~ “ U ° h al " m “ , disS0,ve > and a little euni.ffirms a 
fitatiou by the gum? P C0 “ W * t m fonm “* a lake > retarding its preoi- 
