ON THE IMPURITIES OF COMMERCIAL ZINC, : 99 
l. Silesian zinc. 
2. Vieille Montagne (Belgian) zinc. 
9. New Jersey (American) zinc. 
WACKENRODER, in an excellent paper on the oxide of zinc, maintains that the principal impurities of Sile- 
sian zinc are lead, cadmium, and iron. He found no arsenic in his own experiments, but admits the possibility 
of its occurrence in small quantities. "Traces of copper he believes to exist in this zinc, but neither cobalt, nickel, 
nor manganese, as had been intimated by Hermann (Gilbert's Ann. der Phys., LXVI. 284). He observed 
the development of sulphuretted hydrogen from zinc treated with dilute chlorhydric acid ; but doubts the occur- 
rence of carbon in zinc, except as minute, accidental splinters, thus contradicting Foureroy. Ann. der Pharm., 
1834, X. 53. 
Turner. “lt (zinc) frequently contains traces of charcoal, sulphur, cadmium, arsenic, lead, and copper; 
and iron is always present." Elements of Chemistry, 5th edition, 1834, p. 543. 
Farapay. “Most zinc leaves, when dissolved in dilute sulphuric acid, more or less residue, which contains 
various metals in the metallic state, as copper, lead, tin, iron, cadmium, Ae" Ann. der Pharm., 1836, 
XVII. 21. 
"WirrsTEIN says that the metals with which common zinc is contaminated are iron, cadmium, tin, and lead. 
Cited in Ann. der Pharm., 1836, XX. 179. 
Kane. “The zinc of commerce is impure ; it contains traces of carbon, iron, cadmium, and often arsenic.” 
Elements of Chemistry, 1842, p. 602. 
BARRUEL says that he analyzed a quantity of the residues from zincs dissolved in dilute acid, which had 
accumulated in the laboratory of the Sorbonne during some years, and found in this mass (of very question- 
able origin) 58.5 tin, 34.5 lead, 5.5 sulphur, besides traces of iron, manganese, &c., which he did not determine. 
Wishing to verify this result, he examined the residue from some other zinc, and inferred that it was chiefly 
tin; but his own statement of the process employed would not lead to this conclusion. Comptes Rendus, 1842, 
XIV. 724. 
ERDMANN and MARCHAND cite this observation in their journal, and remark in a note that an examination 
of similar residues gave them lead and tin, with traces of iron, carbon, and cadmium. Journal für pr. Chem., 
1842, XXVI. 384. : | 
A. ERDMANN noticed the occurrence of lead in zinc, and the impossibility of completely separating the lead by 
redistillation, because of the partial volatilization of the lead. Annalen der Ch. u. Pharm., 1844, L. 437. 
BERZELIUS. “It (the zinc of commerce) contains often iron, lead, arsenic, copper, and charcoal" Traité 
de Chemie, Paris, 1846, II. 604. “We are ignorant to what extent zinc combines with carbon, but the 
zinc found in commerce always contains some” Ibid., 616. 
Ure. “The ordinary zinc found in the market is never pure; but contains lead, cadmium, arsenic, copper, 
iron, and carbon, from some of which it may be freed in a great degree by distillation; but even after this pro- 
cess it retains a little lead, with all the arsenic and cadmium." Dictionary of Arts, &c., 4th edition, Boston, 
1853, II. 994. 
PrLouzE and Fremy. “The zinc of commerce is never pure. It contains about a hundredth of its weight 
of foreign bodies, which are chiefly lead and iron ; carbon, copper, cadmium, and arsenic are sometimes found 
in it" Traité de Chimie Générale, 2° édit., 1854, III. 35. 
W. A. MILLER. “Commercial zinc contains a small quantity of lead and iron, and of a peculiar carbona- 
ceous matter.” Elements of Chemistry, 1856, Part IL 847. 
