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XLVI. Experiments relative to Coals and Cokes obtained 

 from Wood and Pit -coal. By David Mushet, Esq. 



J. need hardly remark, that charcoal is composed of pure 

 carbon, or diamond, combined with a certain portion of 

 oxygen — and is therefore considered as an oxide. Oxides of 

 carbon are furnished in greater or less portions, and of va- 

 rious degrees of purity, by every substance in the vegetable 

 kingdom. Almost every substance in the animal ceconomy 

 yields it, and frequently in a state of comparative purity. In 

 the mineral kingdom, in pit-coal, plumbago, mineral pitch, 

 naphtha, &c , we find it bearing a greater proportion to the 

 other ingredients of the compound than either in the ani- 

 mal or vegetable departments. 



The proportion of oxygen united with carbon to form 

 charcoals has not hitherto been ascertained ; btit from the 

 great dose necessary to form carbonic acid, it is probable that 

 some oxides contain from 30 to 50 per cent. 



This will be made to appear highly probable, from the 

 combustion or distillation of different substances in close 

 vessels. No direct experiment has been hitherto made to 

 ascertain the precise quantity of oxygen united to the coaly 

 residue obtained in the preparation of coke, charcoal, or 

 any species of coal ; but by a comparison of their carbo- 

 nating effects, when applied as agents in the dry way of ex- 

 periment, or even upon the more enlarged scale of manu- 

 facture, we may form a pretty correct estimate of their real 

 value, or their approximation to the state of diamond. 



From numerous experiments which I have made, it ap- 

 pears to me highly probable, that the oxide of diamond exists 

 ready formed in almost every substance that yields a car- 

 bonaceous residuum. It has been conceived by some, that 

 the oxide is formed in consequence of the ignition of the 

 substance from which charcoal is meant to be obtained, by 

 the combination of the oxygen liberated from the atmosphe- 

 ric air, or from surrounding bodies ; and that, accordino- to 

 the quantity of oxygen combined with the matter of carbon, 

 the resulting oxide would be more or less debased. It is 



U 3 probable 



