INK. 
ject, found that in most of these the colour 
might be restored, or rather a new body of 
colour given, by penciling them over with a 
solution of prussiate of potash, and then with 
a dilute acid, either sulphuric or muriatic ; 
or else vice versa, first with the acid, and 
then with the prussiate. The acid dissolves 
the oxide of iron of the faded ink, and the 
prussiate precipitates it again of a blue, which 
restores the legibility of the writing. If this 
be done neatly, and blotting paper laid 
over the letters as fast as they become visi- 
ble, their form will be retained very dis- 
tinctly. Pencilling over the letters with 
an infusion of galls also restores the black- 
ness to a certain degree, but not so speedily 
nor so completely. 
The blackness of common ink is almost 
instantly and irrevocably destroyed by the 
oxymuriatic acid, and hence any writing 
may be effaced by this method completely. 
To prevent this mischief, which might often 
be a serious one, several additions have 
been proposed to common ink, of which by 
far the best is lamp-black or charcoal, in 
impalpable powder, on which the acid has 
no effect. The lamp-black should be of the 
least oily kind, as it does not readily mix 
with the ink, and some pains must be taken 
to incorporate them. On this account per- 
haps common charcoal is preferable. About 
a quarter of the weight of the vitriol used 
will be amply sufficient. This will not 
fade by age. 
Ink, China or Indian. The well known 
and much admired Indian or China ink, is 
brought over in small oblong cakes, which 
readily become diffused in water by rubbing, 
and the blackness remains suspended in it 
for a considerable time, owing to the ex- 
treme subtlety of division of the substance 
that gives the colour, and the intimacy with 
which it is united to the mucilaginous mat- 
ter that keeps it suspended. 
Indian ink does, however, deposit the 
whole of its colour by standing, when it is 
diffused in a considerable quantity of water. 
Dr.Lewis, on examining this substance, found 
that the ink consisted of a black sediment, 
totally insoluble in water, which appeared to 
be of the nature of the finest lamp-black, and 
of another substance soluble in water, and 
which putrified by keeping, and when eva- 
porated left a tenacious jelly exactly like 
glue or isinglass. It appears probable, 
therefore, that it consists of nothing more 
than these two ingredients, and probably 
may be imitated with perfect accuracy by 
using a very fine jelly, like isinglass or size, 
and the finest lamp-black, and incorporating 
them thoroughly. The finest lamp-black 
known is made from ivory-shavings, and 
thence called ivory-black. 
Ink, printer’s. This is a very singular 
composition, partaking much of the nature 
of an oil varnish, but differing from it in the 
quality of adhering firmly to moistened pa- 
per, and in being to a considerable degree 
soluble in soap-water. 
It is, when used by the printers, of the 
consistence of rather thin jelly, so that it 
may be smeared over the types readily and 
thinly, when applied by leather cushions, 
and it dries very speedily on the paper 
without running through to the other side, 
or passing the limits of the letter. 
The method of making printer’s ink is 
thus described by Dr. Lewis. Ten or 
twelve gallons of nut-oil are set over the 
fire in a large iron pot, and brought to boil. 
It is then stirred with an iron ladle, and 
whilst boiling, the inflammable vapour rising 
from it either takes fire of itself or is 
kindled, and suffered to burn in this way for 
about half an hour, the pot being partially 
covered so as to regulate the body of the 
flame, and consequently the heat communi- 
cated to the oil. It is frequently stirred 
during this time, that the whole may be 
heated equally, otherwise a part would be 
charred and the rest left imperfect. The 
flame is then extinguished by entirely co- 
vering the pot. The oil by this process has 
much of its unctuous quality destroyed, and 
when cold is of the consistence of soft tur- 
pentine, and is then called varnish. After 
this it is made into ink by mixture with the 
requisite quantity of lamp-black, of which 
about two ounces and a half are sufficient 
for sixteen ounces of the prepared oil. The 
oil loses by the boiling about an eighth of 
its weight, and emits very offensive fumes. 
Several other additions are made to the oil 
during the boiling, such as crusts of bread, 
onions, and sometimes turpehtine. These 
are kept secret by the preparers. The in- 
tention of them is more effectually to de- 
stroy part of the unctuous quality of the oil, 
to give it more body, to enable it to adhere 
better to the wetted paper, and to spread 
on the types neatly and uniformly. 
Besides these additions, others are made 
by the printers, of which the most important 
is generally understood to be a little fine 
indigo in powder, to improve the beauty of 
the colour. / 
Red printer’s ink, is made by adding to 
the varnish, about half its weight of vermi- 
