I N K, 
decaying by waffling over the paper to be .written upon 
with the colouring matter of Pruffian blue, which will 
no( deprave it in colour, or any other refpefl. By writ¬ 
ing upon it with common ink afterwards, a ground of 
Pruffian blue is formed under every ftroke; and this re¬ 
mains ftrong after the black has been decayed by the wea¬ 
ther, or deltroyed by acids. Thus the ink will bear a 
larger proportion of vitriol at firft, and will have the ad¬ 
vantage of looking blacker when firft written. 
For written documents of great importance, it might 
be worth while to be at extraordinary expence tor incom- 
bufiible paper and indelible ink. The former of thefe may be 
prepared from the fibres of amianthus ; the procefs of 
which is the fame as that employed for common paper, 
except that a greater proportion of pafte or fize is required. 
For the ink, the following receipt will be perfectly effica¬ 
cious: Take one part of fulphat of iron (green vitriol) 
and two parts of alum, diffolve them together in warm 
water, and then add pearl-afli as long as any precipitate 
takes place ; boil the mixture, and throw it on a filter ; 
allow the precipitate to drain after being wafhed with 
warm water, and, while yet foft, diffolve it in diftilled vi¬ 
negar ; ufe this moderately concentrated for ink, and the 
characters, after the paper has palled through fire, will be 
of a yellowifh-brown colour, and fufficiently legible. 
Indian Ink, a valuable black for water-colours, brought 
from China and other parts of the Eaft Indies, fometimes 
in large rolls, but more commonly in fmall quadrangular 
cakes, and generally marked with Ciiinefe characters. 
Dr. Lewis, from experiments made on this fubftance, hath 
fhown that it is compofed of fine lamp-black and animal 
glue; and accordingly, for the preparation of it, he de- 
iires us to mix the lamp-black with as much melted glue 
as is fufficient to give it a tenacity proper for being made 
into cakes; and thefe when dry, he tells us, anfwered as 
well as thofe imported from the Eaft Indies, both with 
regard to the colour and the freedom of working. Ivory- 
black, and other charcoal-blacks, levigated to a great de¬ 
gree of finenefs, anfwered as well as the lamp-black; but 
in the ftate in which ivory-black is commonly fold, it 
proved much too gritty, and feparated too haftily from 
the water. 
Coloured Inks. —Writing-ink may be compofed of 
almoft any colour by fome of the procelfes noticed under 
Chemistry and Dying ; thus, in making Pruffian blue, 
(vol. iv. p. 300.) we form an excellent blue ink. The 
following receipts are from the fecond volume of the 
Handmaid to the Arts; and fee farther under the article 
Pigment. 
To make Red Ink .—Take of the rafpings of Brafil-wood 
a quarter of a pound, and infufe them, two or three days 
in vinegar, which fhould be colourlefs, where it can be fo 
procured. Boil the infufion an hour over a gentle fire, 
and afterwards filter it, while hot, through paper laid in 
an earthen colander. Put it again over the fire, and dif¬ 
folve in it, firft half an ounce of gum arabic, and after¬ 
wards of alum and white fugar each half an ounce. Care 
fhould be taken that the Brafil-wood be not adulterated 
with Brafiletto or Campeachy wood, which is moftly the 
cafe when it is ground; and, though a very detrimental 
fraud in all inftances of the application of Brafil-wood to 
the forming bright red colours, cannot yet be perceived 
after the mixture of the rafpings, but by trial of uiing 
them; it is therefore much the belt way, when wanted 
for purpofes like this, to procure the true Brafil-wood in 
pieces, and to fcrape it with a knife or rafp it with a very 
bright file, (but all ruft of iron muft be carefully avoid¬ 
ed,) by which means all poflibility of fophiftication is of 
•courfe prevented. Red ink may likewife be prepared, by 
the above procefs, of white wine inftead of vinegar; but 
it fhould be four, or difpofed to be fo, otherwife, a third 
or fourth of vinegar fhould be added, in order to its 
taking the ftronger tinfture from the wood. Small beer 
has been often ufed for the fame purpofe, but the ink will 
not be fo bright; and, -when it is ul'ed, vinegar Ihouid be 
added, the quantity of gum arabic diminiftied, and the 
fugar wholly omitted. , 
Preparation oj Red Ink from Vermilion. —Take the glare of 
four eggs, a teafpoon-full of white fugar or fugar-candy 
beaten to powder, and as much fpirit of wine, and beat 
them together till of the coniiftence of oil; then add fuch 
a proportion of vermilion as will produce a red colour 
fufficiently ftrong, and keep the mixture in a fmall phial, 
or well-ftopped ink-bottle, for ufe. The competition 
fhould be well lhaken together before it be ufed. Inftead 
of the glare of eggs, gum-water is frequently ufed; but 
thin fize, made of ifinglafs with a little honey, is much 
better for the purpofe. 
To make Green Ink —Take an ounce of verdigrife, and, 
having powdered it, put it to a quart of vinegar; and, 
after it has flood two or three days, ftrain off the fluid.' 
Or, ufe the cryftals of verdigrife diffolved in water; then 
diffolve, in a pint of either of thefe folutions, five drams 
of gum arabic, and two drams of white fugar. 
To make Yellow Ink.- —Boil two ounces of French berries 
in a quart of water, with half an ounce of alum, till one- 
third of the fluid be evaported ; then diffolve in it two 
drams of gum arabic, and one dram of fugar, and after¬ 
wards a dram of alum powdered. 
Of PRINTING-INK. 
The ink ufed by printers is totally different from that 
employed for writing. The ink for the lettcr-prefs is an 
oily compofition, of the confidence of an ointment ; the 
method of preparing it was long kept a fecret by thofe 
whofe employment it was to make it, and who were in- 
terefted in concealing it; and even yet it is but imper- 
ferily known. The properties of good printing-ink are, 
to work clean and eafily, without daubing the types or 
tearing the paper; to have a fine black colour; to wafii 
eafily off the types 5 to dry foon ; and to preferve its co¬ 
lour, without turning brown. This laft, which is a molt 
neceffary property, is effectually obtained by fetting fire 
to the oil with which the printing-ink is made for a few 
moments, and then extinguilhing it by covering the vef- 
fel. It is made to wafh eafily oft' the types, by uiing foap 
in its compofition ; and its working clean depends on its 
having a proper degree of ftrength, which is given by a 
certain addition of rofin. A good deal, however, depends 
on the proportion of the ingredients to each other; for, 
if too much foap be ufed, the ink will work foul, and 
daub the types to a great degree. The fame thing will 
happen from uiing too much black, at the fame time that: 
both the foap and black hinder the ink from, drying ; 
while too much oil and rofin tear the paper, and hinder 
it from walhing off. The following receipt has been 
found to make printing-ink of a tolerable good quality. 
Take a Scots pint of linfeed oil, and fet it over a pretty 
brilk fire in an iron or copper veffel capable of holding- 
three or four times as much. When it boils ftrongly, 
and emits a thick fmoke, kindle it with a piece of paper, 
and immediately take the veffel off the fire. Let the oil- 
burn for about a minute ; then extinguilh it by covering 
the veffel; after it has grown pretty cool, add two pounds 
of black rofin, and one pound of hard foap put into 
Dices. If the oil is very hot when the foap is added, al¬ 
moft the whole mixture will run over the veffel. The 
mixture is then be fet again over the fire; and, when the 
ingredients are thoroughly melted, a pound of lamp-black, 
previoufly put through a lawn fieve, is to be llirred into 
it. The whole ought then to be ground on a marble 
ftone, or in a levigating-mill. 
The ink for the rolling-prefs, or copper-plate prefs, is made 
of linfeed oil burnt in the lame manner as that for com¬ 
mon printing-ink, and then mixed with Frankfort-black, 
and finely ground. There are no certain proportions 
which can be determined in this kind of ink; every work¬ 
man adding oil or black to his ink as he thinks "proper, 
in ordef to make it fuit his own tafte. Some, however,. 
HP a portion of common boiled oil, which has never 
betst. 
