S88 
Cast Steeh 
tie glass, either in a black lead crucible, or in a common 
crucible with a small proportion of lamp-black, or the 
soot of train oil. 
In making cast steel, I understand there is uniformly a 
loss : in making blistered steel, there is a gain of about 
half a pound in the hundred weight, which in some 
measure designates the quantity of carbon taken up by 
and united to the iron in manufacturing steel of cementa- 
tion. 
The charcoal in a steel furnace, is generally so much 
exhausted as not to answer for a second cementation ; 
that is in point of profit. 
The principal characters of steel are the following. — - 
It becomes harder on being made red hot, and then sud- 
denly quenched in cold water. — It takes a much higher 
polish than iron, with a light grey, not a blue cast or hue — 
If a drop of dilute nitric acid (aqua fortis mixed with 
three times its bulk of water) be put upon clean steel, and 1 
after a minute, washed away without being wiped off, it t 
leaves a black spot, because although the acid will dis- 
solve the iron, it will not dissolve the charcoal. The : 
same acid leaves no such black spot when dropt on clean i 
iron : only a slight grey tinge — Steel can be made much 
more elastic than iron : a steel sword may be bent in a vice 
from heel to point, and when let loose will suddenly re- 
gain its former shape ; it is more sonorous than iron; 
its grain, or fracture, is finer than that of iron ; it expands 
by heat more than iron ; it can be beaten into thinner 
plates than iron ; it acquires magnetic power more slow- 
ly, but retains it longer than iron ; red hot steel, quench- 
ed in cold water, retains two thirds of its red-heat bulk, 
but iron on being so treated, contracts to its original size :j 
previous to heating ; steel heats quicker, and fuses 
much more easily than iron ; on being fused and cast, it 
retains the property of malleability, except at a white 
