418 
Cast Steel . 
tains ; when slightly charged with this substance it is mal- 
leable, ductile, weldable and elastic, but when more near- 
ly saturated with carbon it is not capable of being welded* 
and its fusibility is increased. It may be hardened by sud- 
den cooling, and may afterwards be made softer by tem- 
pering. Its specific gravity varies much : that of the best 
blistered steel before hammering is =7.31, of the same af- 
ter hammering =7.73 : of very hard steel =7.26: of 
melted steel wire =7.5 : of English cast steel hammered* 
from 7.82 to 7.91. 
Report concerning the Art of making fine Cutlery — Front 
4 Nicholson* $ Journal , quarto , page 127. 
The fabrication of edge tools is one of the first arts 
among men in every state of society. Artizans are well 
aware of the necessity, that the instruments of their res- 
pective trades should be made to possess the qualities 
adapted to the operations by which they gain their sub- 
sistence ; and among the various sub-divisions of labour, 
there is perhaps no material, upon which the skill and 
judgment of practical men are more multifariously ex- 
ercised than steel. The makers of files, of chissels, of 
planes, saws, and the infinite variety of knives, all occupy 
their several departments separate from each other, and 
possess their respective degrees of celebrity among work- 
men, which are grounded on their knowledge of the pe- 
culiar kinds of steel, as well as the methods of working 
them, which are best suited to the intended operations. 
Many of these methods are kept secret ; but in general 
the philosophical enquirer will find the communications 
of operative men, to the full, as liberal and open as the 
circumstances of the case may seem to warrant. Many 
manufacturers have no reserve with regard to the manipu- 
lations of their art, and have the spirit to assert their 
claims to public encouragement, upon the open ground 
