ON MARKING INKS. 
165 
in ammonia, a circumstance by which it is easily distin- 
guished from some other chlorides, which like it are white 
and formed by precipitation. We should be cautious in ap-, 
plying heat to the ammoniacal solution, as it sometimes forms 
a precipitate of fulminating silver." 
Now it appears to be an indisputable fact, that in precipita- 
ting the oxide of silver with excess of ammonia, or in digest- 
ing its oxide, chloride, or carbonate, in ammonia, a portion of 
a fulminating substance is an extremely likely if not a neces- 
sary result. The same would be the case were either plati- 
num or gold similarly treated. The testimony of, I believe, 
all our Professors of Chemistry will bear out this statement. 
The evidence of Mr. Smee and of Mr. Walker also shows us 
that the soluble triple salts are equally dangerous ; and with- 
out wishing to pry into the legitimate secrets of our brethren 
it certainly behoves us to inquire, ivhether it be possible to 
make an ink which shall contain ammonia, and neither 
of those metals to which I have adverted. Jilso, whether 
it be possible to have any preparation of those metals, 
in which ammonia shall be employed, without the pro- 
duction of a detonating substance. 
Or to put the question in another way : Is the formation 
of these dangerous compounds an invariable, or only an 
occasional or accidental consequence of the combination 
of those metals with ammonia ? If the latter, is it not 
desirable to be made acquainted with the circumstances 
which may thus accidentally give rise to the formation of 
the fulminates, so as to be able to avoid them in the prepa- 
ration of marking inks ? 
It may be urged, that I am needlessly alarmed, that such 
accidents as I apprehend from the use of these inks have not 
been known to happen ; and, moreover, that the presence of 
moisture in the ink is a sufficient preventive of danger. I 
cannot help thinking otherwise. I have not unfrequently 
had bottles of the old marking ink brought to me by persona 
who complain of its having " dried up," and who have been 
surprised to learn that such has been a natural consequence 
