278 
Steel 
put into large crucibles with a flux.* The crucible is 
then closed up with a lid of the same ware, and placed in 
a wind furnace. By the introduction of a greater or smaller 
quantity of flux, the metal is made harder or softer. 
When the fusion is complete, the metal is cast into in- 
gots, and then called ingot steel ; and that which after- 
wards undergoes the operation of tilting, is called tilted 
cast steel. The cast steel is the most valuable, as its tex- 
ture is the most compact, and it admits of the finest polish. 
Sir T. Frankland has communicated a process, in the 
Transactions of the Royal Society,! for welding cast steel 
and malleable iron together ; which, he says, is done by 
giving the iron a malleable, and the steel a white heat ; 
but, from the experiments which have been made at my 
request, it appears, that it is only soft cast steel, little bet- 
ter than common steel, that will weld to iron : pure steel ! 
will not ; for, at the heat described by Sir T. the best cast 
steel either melts, or will not bear the hammer. It may 
here be observed, as was mentioned before, that steel is an- 
intermediate state between crude and malleable iron, ex- 
cept in the circumstance of its reduction being complete ; 
for, according to the experiments of Reaumur and Berg- 
man, steel contains more hydrogen gas than cast iron, but ii 
less than malleable iron — less plumbagoj than the first, 
but more than the latter ; — -an equal portion of man- 
ganese with each; — -less siliceous earth than either;— 
more iron than the first, but less than the second. Its 
fusibility is likewise intermediate between the ban 
iron and the crude. When steel has been gradually 
* P hil . T rans. 1795. 
t Limestone and bottie glass pounded. The limestone is decom- 
posed, and the steel abstracts an additional dose of carbon, from 
the carbonic acid of the limestone, as is supposed i but I suspect 
a small quantity of lamp-black is added. T. C. 
f Rather carbon. Plumbago or black lead is carbon united tp 
a very small proportion of iron, T. C. 
