6 
WRITING INK. 
Imles*r«ctihle 
inK ff riiap- 
tal. I>ami> 
Mack, nine, 
and a little 
salt. 
miscible with the ink j and by this expedient he supposed that 
an ink might be obtained, which would, be but little, if at all, 
subject to the defect in question. I did not, however, in re- 
peating this experiment, find any considerable benefit from 
cloves, employed in this way, and therefore substituted cam- 
phire, which seemed to answer better, though it appeared to 
give the ink a blueish tint j but I have been since convinced, 
that neither these, nor any other means, will completely obviate 
the mouldiness in question, so long as ink retains the viucilagi- 
nous part of galls in a liquid state. 
M. Chaptal observes*, that since the oxygenated muriatic 
acid has been found cap.able of discharging the colour of com- 
mon writing ink both from parchment and paper, without 
injuring their texture, It has been fraudulently employed to 
efface particular parts or words of deeds, contracts, and other 
writings, for which others have been substituted, leaving the 
signatures untouched ; and that, in consequence of-these frauds, 
the commercial part of society, as well as governments, became 
solicitous for the discovery of some composition, which might 
be employed instead of common writing ink, w'ithout its de- 
fects, and therefore, (being then minister of the interior of 
France, and possessed of great chemical science) he, as might be 
expected, occupied himself particularly with that subject j and 
he states, that up to the then present time, the composition 
which had been fournl most useful for this purpose, consisted of 
a solution of glue in water, with which a sufficient portion of 
lamp-black, and a little sea-salt were intimately mixed by rub- 
bing them together on marble. This composition was made 
sufficiently thin (by water) to flow readily from the pen 5 and 
he desciibes it as being “ /res tow j” and capable of 
resisting the action, not merely of cold, but of boiling water ; 
and also of acids, alkalies, and spirit of wine ; and attended 
with nc inconvenience; but that of abrasion, by being rubbed. 
(“^ File n’a que I’inconvenient de s’estomper par le frottement.’ ) 
Though I have never made trial of this composition, I can 
’ Cheiuic appliquCt aux .Arts, tom. iv. p. 24 J. 
readily 
