152 NATURE OF THE DIAMOND. 



of a little more than 10. 1 oz. of water. The temperature of the 

 room when the air was measured, was at 55", and the barometer 

 stood at about 29.8 inches. 



From another experiment made in a similar manner with 1 gr. 

 and a half of diamonds, the air obtained occupied the space of 

 6.18 oz. of water, according to which proportion the bulk of the 

 fixed air from 2 and gr. would have been equal to 10.3 oz. 



The quantity of fixed air thus produced by the diamond, does 

 not differ much from that which, according to M. Lavoisier, might 

 be obtained from an equal weight of charcoal. In the Memoirs 

 of the French Academy of Sciences, for the year 1781, he has 

 related the various experiments which he made to ascertain the 

 proportion of charcoal and oxygen in fixed air. From those which 

 he considered as most accurate, he concluded that 100 parts of 

 fixed air contain nearly 28 parts of charcoal and 72 of oxygen. 

 He estimates the weight of a cubic inch of fixed air, under the 

 pressure and in the temperature above-mentioned, to be .695 parts 

 of a grain. If we reduce the French weights and measures to 

 English, and them compute how much fixed air, according to this 

 proportion, 2} grs. of' charcoal would produce, we shall find that 

 it ought to occupy very nearly the bulk of 10 oz. of water. 



M. Lavoisier seems to have thought that the aerial fluid produced 

 by the combustion of the diamond was not so soluble in water as 

 that procnred from calcareous substances. From its resemblance 

 however, in various properties, hardly any douht could remain 

 that it consisted of the same ingredients ; and I found, on com. 

 Lining it with lime, and exposing it to heat with phosphorus, that 

 it afforded charcoal in the same manner as any other calcareous 

 substance. [Phil. Trans. 1797. 



Since the above account, M. Guyton de Morveau having burnt 

 the diamond in oxygen gas, by the solar rays, and thereby 

 obtained carbonic acid without residue, presumed that he had 

 ascertained the diamond to consist of pure carbon, or the pure 

 principle of charcoal, that which yields the pure acidifiable basis 

 of the carbonic acid. But it was Clouet who proposed the con- 

 clusive experiment of making soft iron pass to the state of steel, 

 by cementation with the diamond. To this end he secured a dia- 

 mond with some filings of iron, in a cavity bored in a block 

 of soft iron, filling up the cavity with a stopper of iron. The 



