Iron . 
215 
Iron ores frequently contain copper, and if it be in a 
proportion more than about 12 per cent . the iron is mani- 
festly the worse for it. The combination of good copper 
with good iron does not make it better ; and the process of 
manufacturing malleable iron from the ore, is not sufficient 
to produce good copper. Where the copper is in large 
proportion, I know not as yet any method of separating it 
profitably. Such methods are noticed by Jars and Schlut- 
ter, but they are not sufficiently detailed to be relied on. 
With respect to the qualities of cold and red short iron, 
I cannot find any information on which my readers can 
rely as to the cause. Whether it be owing to an overdose 
of carbon, to siderite, to arsenic, to manganese, to copper, 
is not yet settled. The cure can only be found in the re- 
finery furnace, and the tilt hammer, or the rollers. 
Of the Refinery or Bloomery , and the conversion of crude 
iron into malleable iron . 
There has been no regular analysis of cast iron, but from 
the phenomena that take place during its conversion into 
bar iron, which we shall proceed to describe, it will be 
sufficiently apparent what are its principal constituent 
parts. 
One of the most obvious differences between cast and 
bar iron, is the brittleness of the former and the malleabi- 
lity of the latter : this malleability has accordingly been 
adopted by the manufacturer as the essential character of 
bar iron, and as affording him a mode by which to judge 
of the efficacy of the means employed by him in reducing 
crude to malleable iron. 
The first step in the process is refining^. For this 
purpose the pigs are smelted in a refinery, (the construc- 
tion of which we have already noticed) by means of char- 
* Collier in Manchester, Trans. 
