Cast Steel . 
381 
but pure carbon similar to the diamond has combined 
with the iron* If, however, the equilibrium is destroyed 
by a larger portion of charcoal, then we find the affinity too 
Weak to deoxidate the whole, and part of it unites in the 
state of an oxide of carbon ; at first constituting a mot- 
tied fracture, and afterwards, as the dose is increased, all 
those deepening blueish grey shades peculiar to soft cast 
iron. Hence carbon or its oxide again softens iron. It 
never, however, restores the properties of forging or of 
hammering. One invariable law, however, is maintained, 
that the fusibility of iron under every circumstance and 
modification is in the ratio of the quantity of carbon uni- 
ted.” 
In consequence of these experiments, Mr. Mushet took 
out a patent for the manufacture of cast steel, which is 
couched as follows. 
Account of Mr. Mushet’s new Method of making Steel 
of various Qualities. 
“ For this invention Mr. Mushet* has obtained his Ma- 
jesty’s royal letters patent ; and, certainly, few discoveries 
of so much importance to this country have been made 
for a number of years past. The manufacture of cast 
steel, which has hitherto been tedious and expensive, is 
now reduced to a process of a few hours ; and the quality 
of the article at the same time so much improved, as to 
be applicable to many purposes to which steel of the com- 
mon manufacture cannot be applied. We shall not, how- 
ever, dwell on the utility of the invention, but lay before 
our readers an account of it, extracted from Mr. Mush- 
et’s specification, which will speak m ore to an intelligent 
mind than would a volume of eu login m. 
* Mushet’s experiments have certainly thrown great light on the 
theory of steel ; hut I do not know whether his patent has been ex- 
tensively used, or his steel compared with Huntsman’s- T. C- 
.3 C 
