127 
Nature of the 'Diamond . 
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 ac- 
curate, 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 abovementioned, to be .695 parts of a grain. 
If we reduce the French weights and measures to English, and 
then compute how much fixed air, according to this proportion, 
two grains and a half of charcoal would produce, we shall find 
that it ought to occupy very nearly the bulk of 10 ounces 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 procured from calcareous substances. From 
its resemblance, however, in various properties, hardly any 
doubt could remain that it consisted of the same ingredients ; 
and I found, upon combining it with lime, and exposing it to 
heat with phosphorus, that it afforded charcoal in the same 
manner as any other calcareous substance. 
