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XXIV. On the different Proportions of Carbon which confti- 

 tutc Crude Iron and Steel, By David Mushet, Efq. 

 . of the Calder Iron IForks*. 



lVlY Iaft communication contained feveral experiments to 

 prove the quantity of carbon abforbed by pure malleable iron 

 in palling into the carbonated crude ftate. The object of 

 the prefent will be to exhibit the proportions of carbon 

 which enter into the composition of the other varieties of 

 crude iron and caft fteel. I continue the numeration of the 

 experiments from my laft : Grs. 



Exp, VII. Swediih bar iron - - 1*74 



Charcoal T jth part, or 78 grs. 

 A fufion was obtained from this mixture, after which 

 there remained only a fmall portion of charcoal, too 

 minute for weighing. 



The metallic button weighed - 1213 



Gained in weight by the combination of charcoal 39 



equal to y^th part the weight of the iron. 



Weight of the iron 1174, and charcoal 78, = 1252 

 Weight of the button - - 13 13. 



Total lofs of weight in the fufion 39 



equal to that gained by the iron. Upon minute infpe&ion, 

 bo part of the furface of this button was carbonated. The 

 colour was blueifh black, fmooth in the centre but a little 

 oxidated towards the edges. Its fracture prefented clofe dark 

 gray crude iron. The cryftals much clofer and more minute 

 than in thofe experiments where richly carbonated crude 

 iron was obtained. Appreciating its real quality by compa- 

 rifon with crude iron manufactured for fate, it occupied that 

 rank generally known by the names of No. II. gray melting 

 pig iron. Grs. 



Exp, VIII. Swediih bar iron - - 922 



Charcoal -~th part, or 46 grs. 

 From the expofure of this mixture there refulted a 

 very perfect metallic button whofe upper furface pre- 

 fented a partial degree of radiated cryftallization. It 

 was found to weigh ... 9^0 



Gained in weight by the combination of carbon 28 



equal to T z T d part the original weight of the iron. The frac- 

 ture of this button was fmooth, filvery white, occafionally 

 iiudded with carbonaceous fpecks in the form of fmall 



* Communicated by the Author. 



grains, 



