286 Vbe Diamond cryftallized Charcoal. [Book VL 



water, and with acids afforded nitrous and fixed air j 

 and appeared, in fact, to confift of nitre partly dec'om- 

 pofed, and of alkali united with fixed air. 



In order to eftimatethe quantity of carbonic gas which 

 might be obtained from a given weight ofdiamond, two 

 grains and an half were inclofed in a tube with a quarter 

 of an ounce of nitre. After the procefs, the alkaline 

 matter contained in the tube was diffolved in water, 

 and the whole of the diamonds was found to be con- 

 fumed. Into the alkaline folution a quantity of fatu- 

 ratcd folution of marble in marine acid was poured, 

 and after the fixed air had united with the calcareous 

 earth, the alkali remained in folution with the marine 

 acid. The clear liquor was then poured off from the 

 calcareous precipitate, and was found to contain no 

 fixed air. The carbonic acid gas being then expelled 

 from the calcareous matter by the addition of an acid, 

 occupied a fpace equal to about 10 ounces of water, 

 which, according to the calculations of Lavoifier, is 

 exactly the quantity that would be produced by the 

 converfion of 2 grains of pure and folid charcoal 

 into an aerial form. That the fixed air, thus produced, 

 confided of the fame matter as that of charcoal, 

 Mr. .Tennant proved by combining it with lime, and 

 expofing it to heat with phofphorus, when he found 

 that it afforded charcoal in the fame manner as any 

 other calcareous fubftance. 



Mr. Tennant repeated the experiment with i f- 

 grains of diamond, and the refuit was the fame* 

 Upon thefe evidences therefore he concludes, and ap- 

 parently with reafon, that this peculiar and beautiful 

 fubftance, fo valued by the higheft claflcs of mankind, 

 the decoration of royalty, and the emblem of all that is 

 pure and excellent in nature, is no other than that de- 

 fpifed matter, charcoal, in a ftate of cryftallization. 



