ON THE YEGETABLK ORIGIN OF DIAMONDS. 85 
which will issue as a fiaal result of its. chemical decoiupositiou, pure 
carbon, and that in a crystallized form." Indeed a higli temperature 
is adverse to the formation of diamonds, as diamonds become black 
when subjected to a high degree of temperature, andj according to Des- 
pretz's experimenis, they are even converted into graphite and coke. 
The black diamonds, or so-called "carbonates of Bahia/' are in part a 
mixture of unciystallized carbon and diamonds, as shown by the process 
of combustion, to which at my desire they were submitted by Professor 
Lowlg. That diamonds originated under Neptunian agency is further 
proved by the frequent occurrence o£ crysfals in them. I have seen 
them in hundreds of different specimens, and even small drusy cavities 
containing them. In my essay I have given ample proof that at one 
lime diamonds were soft bodies. Hitherto only one diamond, in the 
possession of the Emperor of the Erazils, has been known, on which 
the impression of a grain of sand was visible. I have before me a 
rhombic dodecahedron, on the whole surface of wiiich impressions of 
grains of sand are visible, and a similar crystal of the black diamond 
on w^hich the same impressions exist. In a third there is a cavity with 
bent and broken crystals of nn unknown kind. Two others, an octahe- 
dron and a rhombic dodecahedron, have on their surface deep impres- 
sions of crystals which are not those of diamonds. The Neptunian origin 
of diamonds can tlierefore no longer be doubted. G. Bischof also 
thinks that after the discovery of iron pyrites in the diamond any 
doubt respecting the formation of diamonds in a moist w^ay has been 
dispelled. In close connection with these observations is the question 
about the vegetable origin of diamonds, which in a measure w^as an- 
swered by Newton, who regarded them on account of their great power 
of reflecting light, long before their ti'ue etemical condition was ascer- 
tained, to be coagulated fatty or oily bodies. Jameson and Wilson 
endeavoured to prove this theoretically, Petzholdt practically, by the 
vegetable cells found in the ashes of diamonds. The vegetable origin 
of.coal and anthracite, and their sedimentaiy formation, having been 
thoroughly established, I examined, starting from this point, graphite 
(hitherto regarded as being without structure, but doubtless having a 
Neptunian origin) and the diamond ; and by the experience I have 
gained from observing for a nnmber of years, chalcedony and amber, I 
am able lo distinguish sufficiently between mectanical formations and 
formations of a vegetable origin. I have not yet attained any results 
