120 Observations on Iron and Steel. 
‘cold water, it has the hardness and brittleness’ of 
crude iron. 
From ‘the foregoing facts, we are justified in 
drawing the same conclusions with Reaumur and 
Bergman, but which have been more perfectly ex- 
plained by Vandermonde, Berthollet, and Monge, 
that crude iron is a regulus, the reduction of which 
is not complete; and which consequently will differ 
according as it approaches more or less to the 
metallic state. Forged iron, when previously well 
refined, is the purest metal; for it is then the most 
malleable and the most ductile, its power of weld- 
ing is the greatest, and it acquires the magnetic qua- 
lity soonest. © Steel ‘consists of iron perfectly re- 
duced and combined with charcoal; and the various 
differences in blistered steel, made of the same me- 
tal, consist in the greater or less proportion of char- 
coal imbibed. 
Iron gains, by being converted into steel, about 
the hundred and eightieth part of its weight. 
In order to harden steel, it must be put into a 
clean charcoal, coal, or cinder-fire, blown to a suf- 
ficient degree of heat by bellows. The workmen 
say, that neither iron nor steel will harden properly 
without a blast. When the fire is sufficiently hot, 
the instrument intended to be hardened must be put 
in, and a gradual blast from the bellows continued 
until the metal has acquired a regular red heat; it 
is then to be carefully quenched in cold water. If 
