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limited extent to mix with, other kinds of iron, owing to the 
great hardness of the iron produced, by the presence of even 
a very small quantity of titanium, and hitherto the imprac- 
ticability of separating them. 
Iron is manufactured in two forms : as cast-iron, which is 
the condition produced in the blast furnace, and wrought- 
iron, made by decarbonizing the cast-iron, and thus rendering 
it malleable. In order to effect this conversion, great care is 
required. The pig-iron is first refined — that is, melted in an 
open hearth with the purest coke, derived from the Better-bed 
coal, or the Cliurwell thin coal. When in a molten state, it is 
run into iron troughs, and water is thrown upon it, as soon as 
it begins to cool. This process causes the separation of the 
silicon ; it is then puddled and made into stampings. The 
iron is so manipulated in the furnace, that nearly all the 
sulphur and phosphorus are eliminated. The iron is next 
broken up, and, according to the fracture exhibited, is made 
into different articles to correspond with the work which these 
articles have ultimately to perform. The iron is characterised 
by containing a very small percentage of sulphur, phosphorus, 
and silicon, by its great tenacity, by its ductility, and by the 
closeness of its grain, rendering it susceptible of a very fine 
polish. Its value may be judged when we consider that bar- 
iron of common quality may be bought at the present time 
at £8 10s. per ton ; whilst £23 per ton is paid for similar 
bars made from this ore, and locomotive cranks, made of this 
iron, are sold at about Is. Id. per lb. 
COALS. 
We cannot consider the uses to which coals are put, with- 
out the very important fact of enormous waste forcing itself 
on our attention. In the most economical mode of using them, 
only about of the heating power is utilised, and science 
has, as yet, done little towards economising their use. The 
