WRITING INK. 
2 
Chaptal’s ink. boiled in twenty-five times their weight of water, for the space 
of two hours, adding a little water, from time to time, accord- 
ing to the evaporation The decoction so made, he says, will 
commonly mark from 3 to 3| degrees upon the hydrometer of 
Beaume, equal to about 1022 of the common standard. At' 
the same time, a solution of gum arabic is to be made with 
warm water, until the latter will dissolve no more of the for- 
mer. This solution will mark 14 or lo degrees, equal to about 
1110. A solution of calcined sulphate of iron is also to be 
made and concentrated so that it will mark 10 degrees, equal to 
about 1071. And to this, as much sulphate of copper is to be 
added, as will be equal to one-fifteenth part of the galls em- 
ployed to make the decoction. The several matters being so 
prepared, six measures of the decoction are to be mixed with 
four measures of the solution of gum, and to this mixture, 
from three to four measures of the metallic solution are to be 
added, by a little at a time, mixing the several matters each 
time by shaking. Ink so madewill, he says, form nosediment'j 
and he estimates the proportions of solid matters contained in 
it to be 5C0 parts of gum, 462 parts of the extract of galls and 
logwood, and 481 parts of metallic oxides. 
But though the hydrometer may enable those who will em- 
ploy it, to obviate or correct the uncertainties resulting from 
the difference of quality in galls, some persons may wish to 
avoid the trouble of doing so, and choose rather to incur the 
risk of some little defect in the ink they may prepare ; and 
for their satisfaction, therefore, I will mention the following, 
as being generally the most suitable proportions for composing 
the best and most lasting writing ink, viz. 
fioiis of Take of good Aleppo gall, in sorts, coarsely pow'dered, 
author. tw'elve ounces, and of chipped logwood six ounces ; boil these 
Sulphate of in five quarts of soft water, two hoursj and strain ofl' the de- 
jron, galls, and ^ 
sugar. coclion whilst hot j then put to the residuum as much boiling 
water as, when properly stirred, strained, -and added to ih^; for- 
mer, will suffice to moke the whole of the decoction equal to ' 
one gallon } add to this five ounces of sulphate of Iron, with 
the same quantity of gum arabic, and two ounces of good dry 
musco- 
