304 Experiments and Inferences refie^ing the Cotnbujlion of the Diamond. 



their weight of iron, or aluminei afFord, by their combuftion, carbonic acid like charcoal, and 

 the diamond. 



They approach charcoal by their colour, their lightnefs, and their opacity. Like that fub- 

 ftance, they dccompofe water, cement iron, difoxigenate metals, fulphur, phofphorus, and'ar- 

 fenic ; and, like charcoal, they conduct the eleflric fluid. 



, They approach the nature of the diamond in containing much more combuftible matter than 

 charcoal, which is manifefted by their abforbing more oxygen, and producing more^carbonic 

 acid ; in their decompofiflg more nitrous acid ; in their refufing to burn, even in fufed nitre, 

 unlefs at a more elevated temperature ; and by their combuftion ceafing when that tempera- 

 ture is diminifhed. 



They appear to differ from each of thefe bodies, by their property of producing the Gal- 

 vanic irritation with zinc, as well as filver does ; aneffeft which is not produced either with 

 the diamond, or with charcoal. 



12.' The diamond, therefore, is pure carbon, the pure acidifiable bafis of the carbonic 

 acid. 



Its combuftion is efFecSted in three terms, which require three different temperatures. 

 At the firft and moft elevated temperature, the diamond affumes a black, leaden colour. 

 This is a firft degree of oxidation ; it is the ftate of plumbago, and the anthracolite. 



At the fecond temperature, which may be eftitnatcd at eighteen or twenty pyrometric de- 

 grees, there is a new, flow, and fucceflive combination of oxygen. It is a progrefs of 

 oxidation, which ccnftitutes the habitual ftate of charcoal, or rather that in which it is found 

 after the adlion of a ftrong heat in clofed veffels has difengaged part of its oxygen. 



Plumbago is, therefore, an oxide of the firft degree ; charcoal, an oxide of the fecond 

 degree ; and the carbonic acid is the produ£l of the complete oxigenation of carbon. 



Suppofing, therefore, that we could operate with fufficient preciflon to take from the fur- 

 face of the diamond the black matter gradually as it is formed, by withdrawing it fuddenly 

 each time, from the aition of the folar heat, we fliould undoubtedly convert it into char- 

 coal, or at leaft into plumbago, if the too rapid tranfition of the laft degree of oxidation to 

 oxigenation fhould not permit us to obtain it in this ftate. 



13. Laftly, from thefe principles flow many important confcquences to chemiftry and the arts. 

 After this conclufion, it will, no doubt, be demanded, how it happens that the fimple mat- 

 ter, the pure carbon, or diamond, is fo fcarce, while its compounds in different ftates are fo 

 abundantly difperfed. To difpel the aftonifhment of tbofe who might confider this a ground 

 of diftruft, I fhall remind them that the aluminous earth is likewife one of the commoneft 

 fubftances, though the adamantine fpar, no lefs rare than the diamond, is neverthelefs alu- 

 mine j that iron exifts every-where, under every form, excepting in the ftate of purity ; for 

 the exiftence of native iron is ftill doubtful. 7"he wonder coniifts only in the oppofition 

 between facSs and our opinions ; it difappears in proportion as we difcovcr and appropriate 

 the powers of nature to produce the fame efFedts. 



, Thofe who have never turned their attention to the philofophical fciences — at leaft, for the 



purpofe 



