146 On the different Proportions of Carbon 



the dofe of carbon, the metallic refult approached more and 

 more to the foftnefs of malleable iron, though by no means 

 poflefled of all its properties. In this feries of experiments, 

 iron prefented with , ' r th part its weight of charcoal was 

 found to form very foft fteel fit for making fciffars, &c, 

 which, in a good workman's hands, would have doubled, 

 welded, and formed a very perfect point, afterwards harden- 

 ing fp as to difplay a beautiful clofe break of fteel. By ufing 

 the following precaution, it was even found capable of weld- 

 ing perfectly to iron. Two flat bars of a fimilar fhape, one 

 of this quality of fteel, and one of good malleable iron, were 

 put under the hammer with a good welding heat. After a 

 few light blows, the junction was completely made. The 

 united bars were allowed to cool without further hammering 

 till the (hade of heat was bright red. The whole piece was 

 then drawn out in a folid compact form, whofe fracture, 

 v/Jien cold, prefented a complete junction of the iron and 

 fteel, exhibiting at the fame time their refpective grains. 



When iron is prefented in fufion to -ri th or T ycth part of 

 its weight of charcoal, the refulting product: occupies a kind 

 of middle ftate betwixt malleable iron and fteel. It then 

 welds with facility, and, provided the precaution formerly 

 mentioned is attended to, may be joined either to iron or 

 fteel, at a very high welding heat. Thus combined with 

 carbon, it is ftill fufceptible of hardening a little, but without 

 any great alteration in the fraclure. It poffeffes an uncom- 

 mon degree of ftrength and tenacity, capable of an exquifite 

 dere e of polifli, arifing from its complete folidity and the 

 purity of fracture conveyed to it by fufion. 



When the dofe of carbon is further diminiflied, and in the 

 ratio of this diminution, the fame fteel or iron becomes more 

 and more red fhort, and lefs capable of cohefion under a 

 welding heat, fo that, when the proportion is reduced to 

 -7Toc tn P art ^ e w ?igbt of the iron, the quality refulting is 

 nearly analogous to the fufion of iron perje, or that obtained 

 by the fufion of iron and earths. 



It will appear evident from the refult of thefc and former 

 experiments, that crude iron and fteel only differ from each 

 other in the proportions of the carbon they contain. In the 

 details now before us, charcoal alone is ufed in addition to 

 the malleable iron as pure as is ever made, to effect: every 

 principal ftage or modification of ^he metal. Hence we con- 

 clude, that 



Iron femi-fteelified is made with, charcoal, Ty^th part. 



Soft caft fteel, capable of welding, with, - T ~ th 



Caft fteel, for common purpofes, with, - tI?& 



Caft 



