356 
Cast Steel. 
loss, may be preferable to vitreous flux and coal, which 
afford some small additional weight, is not yet as it should 
appear, decided by the actual operations.” 
These experiments of Clouet, were repeated by Mush-* 
et ; who found that no mixture of limestone and clay, no 
fusion with lime alone, or with glass alone, in a common 
crucible, would convert iron into steel ; though the pro- 
perties of the iron were in some degree altered : but when 
the fusion took place in a black -lead crucible, steel was 
uniformly produced. Hence it may be reasonably pre- 
sumed, that the carbon was furnished, not by the decom- 
posed carbonic acid of the limestone, but by the black- 
lead mixed with the crucible ; black-lead being a very 
highly carburetted iron. 
These ideas were pursued by Mushet; who went 
through a course of trials on the fusion of pure malleable 
iron with charcoal alone in various proportions. As Mush- 
et’s experiments, have in my opinion, settled the theory 
of the formation of Steel, I shall give them at length. 
On the different Proportions of Carbon which con- 
stitute the various Qualities of Crude Iron and Steel. 
By David Mushet, Esq . of the Calder Iron Works . 
It is of considerable importance to the manufacturer to 
ascertain the absolute portion of charcoal which in his pro- 
cess becomes united with the metal to form cast iron. 
Having once admitted the fact, that it is in the ratio of the 
carbon presented to the metallic particles that he obtains 
a determinate quality of crude iron, experiment will ena- 
ble him to deduce, that in manufacturing the richest na- 
tures of iron his produce from the ore will be more, by 
the extra quantity of carbon necessary to constitute this 
quality, than when the inferior numbers of iron are produ* 
