386 Eliot and Storer on Arsenic as 
acid, inst of sulphuric, was used in Marsh’s apparatus with 20 
grammes of pure Vieille Montagne zinc, and before the hydrogen gener 
ated had been passing through the heated reduction-tube fifteen minutes, 
From the examination of so few samples of sulphuric and chlorhydn 
acids, we do not pretend to have established the affirmative pene fo 
that there is always arsenic in these acids; their impurity was 0? oi 
incidental difficulty in this research, and we strayed thus far from 
main subject, only because of the great importance of trustworthy infor- 
* For a strong statement of this opinion, see Ure’s Dictionary of Arts, &e,, 4th 
edition, Boston, 1853, vol. ii, pp. 791, 799. 
weigger’s Jour. f. Ch. u. Phys., 1816, xviii, 283. + B60 
Ibid., 1825, xliii, 452. § Ann. des Mines, (4) xix, 6 aii, 408. 
Ch., 1852, lv, 54. {| Ann. d’Hygiene Publique, 2) 
Ann, der Pharm., 1835, xiii, 241. ++ Comptes Rendus, 1841, xu, 
t Ann, der Ch, u. Pharm., 1856, ¢, 39. +. 948, Att 
. re’s Dictionary of Arts, &c., 4th edition, (Boston, 1853,) 4 
