348 
MISCELLANY. 
Arsenic in Muriatic Acid. — At the session of the Academy of Science 
on the 20th of September, Prof. Dupasquier, of the School of Medicine of 
Lyons, read a paper entitled " Memoir on the presence of arsenic in the 
Hydrochloric Acid of commerce, and consequently, in the same acid pu- 
rified for the use of pharmaceutists. and chemical laboratories." The au- 
thor sums up his results as follows : 
1st. That some commercial muriatic acid is found to contain arsenic. 
2d. That such acid, purified by the process ordinarily employed in labora- 
tories, furnishes a hydrochloric acid equally arseniferous. 
3d. That the amount of arsenic contained in such acid is quite appre- 
ciable. A kilogramme of muriatic acid, purified by distillation, gave an 
amount of sulphuret equal togr. 0.722, almost a gramme of arsenious acid. 
4th. The arsenic'contained in this acid is derived from sulphuric acid 
used in the manufacture, which being obtained from pyrites, contains ar- 
senic. 
5th. Experiment has proved that the arsenic does not exist in'the state 
of arsenious acid, but as a chloride, which accounts for its great volatility, 
and its presence in the distilled acid. 
6th. Arsenious acid, then, is convened into chloride and water by the 
action of hydrochloric acid, which offers an explanation of the action of 
this hydracid upon arsenious acid less soluble in pure water. 
7th. The use of an arseniferous hydrochloric acid may occasion serious 
inconvenience, in chemical research, and in the arts. 
8th. This arseniferous acid may also give rise to serious danger, if em- 
ployed as a remedy, or an ingredient of compounds. 
9th. The^use of this acid is particularly dangerous in medico-legal ex- 
aminations, when hydro-sulphuric acid is employed upon a liquid suppos- 
ed to contain arsenic, since an arsenical precipitate will be found, although 
none of this poison be contained in the suspected liquid. 
M. Dupasquier recommends the following mode of rendering the acid 
pure : — mix equal quantities of the acid and water; subject the mixture to 
a current of hydro-sulphuric acid ; separate the sulphuret which results, 
first uniting it by shaking it together. Acid thus diluted may be filtered 
through paper. It is perfectly colourless, and gives no spot with Marsh's 
apparatus. It is true that this mode weakens the acid somewhat, but this 
may be avoided in some measure, by using less water, or by redistilling 
and collecting the gas in less water. 
Robiquet, some time since, had communicated to the Journal de Chimie 
Medicale, that hydrochloric acid might contain arsenic; which he attribut- 
ed either to the sulphuric acid, or the cast-iron cylinders in which the 
chloride of sodium is decomposed. — /our. Chimie. Med, 
At the same sitting, MM. Forbes and Gelis communicated that in using 
Marsh's apparatus, several specimens of purified zinc, and containing not 
