METALLURGICAL COLLECTIONS. 
95 
Oxland’s process for separating wolfram from tin is illustrated 
in this Case. The wolfram is a tungstate of iron and manganese, 
and by calcining the ore with carbonate of soda, a tungstate of 
soda is produced, and this being a soluble salt is readily 
removed by water. 
Zinc-Smelting. 
Table Case 33. — Agricola, and others in his age, regarded 
calamine as an earth containing no metal, although it had long 
been employed in the manufacture of brass. Van Swab in 1742, 
and Magraf in 1746, separated zinc from calamine by distillation 
in close vessels. Pott, in 1741, wrote a dissertation on zinc, in 
which he speaks of it as a semi -metal. The name zinc first 
occurs in the works of Theophrastus Paracelsus. 
The zinc ore, whether calamine or blende, is first roasted, and 
the oxide thus obtained reduced by smelting with carbonaceous 
matter. In this country the reduction was formerly effected in 
a crucible, provided at the bottom with a tube, through which 
the zinc vapour descended. 
The celebrated Vieille Montagne ores have been noticed at 
p. 82. The Abbe Dony first established the smelting works, 
which passed into the hands of the Mosselman family in 1818, 
and in 1837 into the possession of the present proprietors, the 
Vieille Montagne Zinc Company. The distillation is conducted 
in a series of clay retorts, furnished with cast-iron conical 
condensers. 
The extraction of zinc and preparation of the oxide of zinc, or 
zinc white, as conducted by the Lehigh Zinc Company at 
Bethlehem, Pennsylvania, is well illustrated by a large suite of 
specimens presented by the company, and exhibited^ in the Case 
before us. Zinc white is largely employed as a pigment in the 
place of white lead, over which it has the advantage of being less 
poisonous, and of not blackening on exposure to sulphuretted 
hydrogen. 
Brass. 
Table Case 33. — In the arrangement of these Table Cases we 
have first the simple metals, copper, tin, and zinc ; then the 
alloy of copper and tin, forming bronze ; and finally that of 
copper and zinc, forming brass. 
For the production of differently coloured brasses, and to 
meet the required conditions of various manufacturing processes, 
the proportions of copper and zinc in brass are infinitely varied c 
A common proportion is 2 parts of copper to 1 of zinc. 
Formerly brass was manufactured by heating in crucibles a mix- 
ture of granulated copper, calcined calamine (carbonate of zinc), 
and ground coal. At the present day, however, the alloy is pre- 
pared directly by fusing together the proper proportions of 
copper and zinc either in crucibles or in a reverberatory 
furnace. 
