Cast Steel 
35 ? 
tied. In all cases, therefore* in making cast iron, conside- 
rable quantities of the coal become united with the iron, 
forming, by weight, a portion comparatively great. 
From the usual processes hitherto employed in manu- 
facturing blistered steel, the positive quantity of carbon 
which became united with the iron never became an ob- 
ject worthy of the attention of the manufacturer. It was 
sufficient to him that his bars possessed blisters sufficient- 
ly large and prominent to assure him that his steel was suf- 
ficiently converted. The unerring test of practice through 
a long series of operations confirmed the correctness of 
this deduction ; and it must have appeared a matter of 
little importance to the formation of steel, that its direct 
operation of principle should be developed, or the laws 
which regulate its affinity in cementation. 
No additional fact was necessary to the production of 
east steel. The simple fusion of bar steel, regulated by 
such circumstances as practice, and the various uses to 
which this Steel is applied, was all that was necessary to 
be known ; the affinity of iron for carbon, and the various 
proportions in which it exists with the metal, forming the 
different qualities of steel, here met with no elucidation. 
On the contrary, we still find that the union of iron and 
charcoal to form steel, is a matter of doubtful opinion a- 
mong manufacturers, and the weight gained by its cemen- 
tation generally denied.. 
It is only lately that a process has been brought into 
use for making cast steel, which has for its basis or prin- 
ciple the direct proportions of carbon necessary to form 
steel, illustrative at the same time of that beautiful phe- 
nomenon of affinity betwixt iron and carbon, which consti- 
tutes the endless varieties of this metaL 
To investigate this subject with accuracy, it appeared to 
me that a series of experiments, made by the fusion of bar 
