which ccnjlitute Grade Iron and Steel. Jf 



riments with open veflels, a portion of charcoal disappeared 

 always in proportion to the quantity introduce^ and not 

 analogous to the quantity of iron. 



Difappearcd of Charcoal. Iron gained. 



When I was ufed, 34*4 per cent. - 77T tn P art * 



When 4th was ufed, 45 per cent. - — rth part, 



When -^th was ufed, $>] per cent. - — j-th part. 



When |th was ufed, 67*3 per cent. - ■ — ^th part. 



21 



1 o 



When ^th was ilfed, 80 per cent. - "IF** 1 P art 



When -j^th was ufed, 83*5 per cent. - - — d part 



•22 



Upon the whole, if the refults of thefe fix experiments, 

 performed in open veflels, are compared with the three firit 

 detailed in laft communication, where a fimilar quality of 

 crude iron was obtained in veflels perfectly clofe, no material 

 difference will be found. They mutually fupport each other, 

 as to the quantity of carbon neceflary to form crude iron, 

 while they ftill leave in doubt the caufe of the difappearance 

 of the charcoal in clofe veflels. In the cafe of open veflels, 

 it is highly probable that a conflderable portion of the char- 

 coal is deftroyed before the heat of the furnace is fufhciently 

 ftrong to lute the cover of the crucible. 



This, ftill, however, leaves unexplained, why, in experi- 

 ment I. a lofs of 152 grains of charcoal is fuftained ; while 

 in No. VI. the original quantity introduced did not amount 

 to half that quantity, yet 1 2 grains of the latter was found 

 entire refting upon the furface of the reduced metal. The 

 thicknefs and capacity of the crucible in both cafes, and, in- 

 deed, all thefe experiments, were nearly alike. 



The fact of malleable iron being convertible into the moft 

 carbonated ft ate of crude iron, either in clofe or open veflels, 

 where a portion of the carbonaceous matter was found re- 

 poling upon the furface of the newly-changed metal, creates 

 fome doubts as to the exiftence of oxygen in crude iron. If 

 it is admitted that bar iron is deftitute of oxygen, which it is 

 highly probable is the cafe ; if a portion of this iron is intro- 

 duced and fufed along with a portion of carbonaceous matter 

 in a veflel impervious to air, which veflel is found, when 

 cold, to be more than half filled with charcoal, protecting a 



A 4 metallic 



