SI 
MISCELLANY 
On a new method of distinguishing Arsenic from Antimony, in cases of 
suspected poisoning by the former substance, by Mr. J. Marsh. — In testing 
for arsenic in cases of poisoning by that substance, it has always been de- 
sirable to render the process as simple as possible, and thereby divest the 
mind of any ambiguity on the subject. It was with this view, that I sub- 
mitted to the Society of Arts, &c, in the year 1836, my process by hydro- 
gen, a process that I then fondly hoped would have removed all difficul- 
ties ; but a communication from my friend Mr. Lewis Thompson, and 
which was inserted in the London and Edinburgh Philosophical Maga- 
zine, vol. x, p. 353, has rendered the process, in some measure, more 
difficult than was at first supposed, by the discovery of that gentleman, of 
a compound in which antimony combines with hydrogen to form a gas 
(antimoniuretted hydrogen. ) This gas gives off, by the process employed, 
metallic crusts, which much resemble, to the inexperienced eye, the me- 
tallic substance derived from arsenical solutions by the same arrangements. 
It becomes necessary, therefore, to find means of distinguishing these me- 
tallic crusts from each other. Many processes, which are well known to 
the experienced chemist, may be employed for this purpose; but the mis- 
fortune is, that all these arrangements suppose a previous chemical ac- 
quaintance with the subject ; for instance, a good process is given for this 
purpose by Liebig and Mohr, in their valuable journal, {Lieb. Ann, xxiii, 
217,) and also, a modification of the same by Berzelius may be seen copied 
in the Lancet, vol. i, 1838, p. 819, but these are all liable to the above ob- 
jection, viz., a want of simplicity. 
I am happy in being able to lay before your readers a verv simple dis- 
tinguishing test for these bodies, and which I have employed in all cases 
of doubt with perfect success. The means which I use are simply as fol- 
lows : After the common arrangements have been made for testing for an- 
timony or arsenic, the piece of glass or porcelain on which the metallic 
crusts are generally received, is to have a single drop of distilled water 
placed on it; the glass or porcelain is then to be inverted, so that the 
drop of water is suspended undermost. The gas, as it issues from the jet, 
is to be inflamed in the usual manner, but the piece of glass, &c, with its 
drop of water, is to be held about an inch above the jet, or just above the 
apex of the cone of the flame; the arsenic, by this arrangement, is oxidized 
