Chemistry and Physics. 407 
Mr. Bessemer has devoted his attention almost exclusively to the subject. 
Preliminary trials were made on from ten to twenty pounds of iron, and 
“although the process was fraught with considerable difficulty, it exhib- 
ited such unmistakeable signs of success,” Mr. Bessemer observed, “as to 
induce me at once to put up an apparatus, capable of converting about 
seven hundred of crude pig iron into malleable iron in thirty minutes.” 
“I set out with the assumption that crude iron contains about five per 
cent. of carbon; that carbon cannot exist at a white heat in the presence 
of oxygen without uniting therewith and producing combustion; that 
such combustion would proceed with a rapidity dependent on the amount 
of surface of carbon exposed: and, lastly, that the temperature which 
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of coke, so as to dry the brickwork, and heat up the vessel for the first 
operation, after which the fire is to be all carefully raked out at the tap- 
time, becomes 
Worn away, and a new lining is required. I have before mentioned that 
the ftiyares are situated aenly sei to the bottom of the vessel; the fluid 
al will therefore rise some eighteen inches or two feet above them. 
It is therefore necessary, in order to prevent the metal from entering 
___ the tuyére holes, to turn’on the blast before allowing the fluid crude iron 
__ to run into the vessel from the blast furnace. This having been done, 
4nd the fluid iron run in, a-rapid boiling up of the metal will be heard 
