Cast Steel , 
377 
iron. Two flat bars of a similar shape, one of this quali- 
ty of steel, and one of good malleable iron, were put un- 
der the hammer with a good welding heat. After a few 
light blows, the junction was completely made. The unit- 
ed bars were allowed to cool without further hammering 
till the shade of heat was bright red. The whole piece 
was then drawn out in a solid compact form, whose frac- 
ture, when cold, presented a complete junction of the iron 
and steel, exhibiting at the same time their respective 
grains. 
When iron is presented in fusion to ^-—th or -y—th part 
of its weight of charcoal, the resulting product occupies a 
kind of middle state betwixt malleable iron and steel. It 
then welds with facility, and, provided the precaution for- 
merly mentioned is attended to, may be joined either to 
iron or steel, at a very high welding heat. Thus combin- 
ed with carbon, it is still susceptible of hardening a little, 
but without any great alteration in the fracture. It posses- 
ses an uncommon degree of strength and tenacity, capa- 
ble of an exquisite degree of polish, arising from its com- 
plete solidity and the purity of fracture conveyed to it by 
fusion. 
When the dose of carbon is further diminished, and in 
the ratio of this diminution, the same steel or iron becomes 
more and more red short, and less capable of cohesion un- 
der a welding heat, so that, when the proportion is reduc- 
ed to ~^th part the weight of the iron, the quality result- 
ing is nearly analogous to the fusion of iron per se , or that 
obtained by the fusion of iron and earths. 
It will appear evident from the result of these and for- 
mer experiments, that crude iron and steel only differ 
from each other in the proportions of the carbon they con- 
tain. In thedetails now before us, charcoal alone is used in 
addition to the malleable iron as pure as is ever made, to 
effect every principal stage or modification of the metal 
Hence we conclude, that 
