ZINC. 209 
it were possible to discover an easy method of working 
nickel, there can be little doubt but it would be found 
a very valuable metal for surgical instruments, for 
compass needles, and other articles, as it is not, like 
iron, liable to rust. When nickel is freely suspended, 
it points to the north and south, in precisely the same 
manner as the common magnetic needle. 
Oxide of nickel is used for giving colours to enamels 
and porcelain. In different mixtures it produces brown, 
red, and grass-green tints. 
241. ZINC, or SPELTER, as it is sometimes called, is a 
lluish white metal formed in thin plates adhering together. 
It has a very perceptible taste, is about seven times heavier 
than water, rather harder than silver; and possesses but a 
small degree of malleability and ductility, except under certain 
circumstances. 
This metal is never found in a pure state ; and the principal 
ores from which it is procured are known by the names of 
Calamine and Blende. Of these the former is an oxide (21) 
of zinc combined with carbonic acid (26), and the latter is a 
combination of zinc with sulphuric acid (24). 
The ores of zinc are very abundant in many coun- 
tries. We are informed that nearly the whole of Flint- 
shire in North Wales abounds with calamine ; and that, 
so entirely ignorant were the inhabitants of its use, as, 
till after the middle of the eighteenth century, to have 
even mended their roads with it. These roads, however, 
have since been turned up in many places, and the ma- 
terials have been converted to more valuable purposes. 
Derbyshire affords a great quantity of the ores of zinc, 
particularly calamine. This is found at various depths, 
generally in beds of yellow, or reddish brown clay, and 
usually near some vein of lead ore. 
The mode of extracting zinc from its ore is by dis- 
tillation. The process adopted, in some parts of Saxony, 
is equally simple and ingenious. An inclined stone is 
placed near the anterior part of a furnace, in which the 
ore of lead containing zinc is fused. A great part of 
the zinc condenses upon this stone, and flows, in 
