224 
Iron . 
dling furnaces, of its iron, they would be more able to es- 
timate the portion of unmetallic parts contained in their 
crude iron : upon finding the scoria to contain 30, 40, to : 
50 per cent . of iron, equally fit for converting into mak 
leable iron as any part of the original mass, their attention 
would be more frequently arrested, and employed to de- 
vise means, either to prevent the escape of such a consider- 
able proportion of iron, or to fuse such scoria so as to 
deprive it of the last portion of metah ’ '-‘—Mushet* 
Conversion of Pig-iron into malleable Iron , and Steel 
From Dr, Rees's Cyclopaedia, new edition . 
X. Bar , or wrought Iron, Iron, as obtained by the 
reduction of its ores in the blast-furnace, contains, as we 
have before stated, a certain proportion of carbon, which 
renders the metal unfit for the various purposes of forg- i 
ing, but constitutes its principal value as applicable to the 
use of the founder. To deprive it of this ingredient cer- 
tain processes are gone through, the object of which is, 
by the concurrent action of heat and air, to dissipate the 
carbon under the form of an elastic compound. The kind 
of iron chosen for the conversion is that denominated by 
manufacturers forge-pig . It is the lowest quality made 
for the purposes of art ; and, in consequence of its being 
combined with a smaller dose of carbon than any other, 
which thus causes it to bear a less price in the market, is 
doubly preferable for the end required. 
The price of pig-iron is almost exclusively determined 
by the quant it} of carbon which is in combination with 
it. The varieties usually distinguished are No I , other- 
wise called grey, smoothfaced , or kishy , metal ; Nos 2 
and 3, and forge-pig . The proportion of carbonaceous 
matter present in these varieties is differently stated by dif- 
ferent experimentalists. Clouet makes the highest pro* 
portion to amount to |th i but from the results obtained 
