340° Dr George Wilson on the Possible Derivation of 
by the slow spontaneous decomposition of a liguid compound 
of carbon. isd 
My present object is to urge, that, in addition to this and: 
similar views, we are free to inquire whether carbon may: 
not be crystallised from graphite and amorphous carbon, or 
from one of its solid compounds, without passing through an 
intermediate condition of fluidity. 
Professor Jameson long ago suggested that the diamond 
was of vegetable origin ; but I have not been able to procure’ 
his original paper. Sir David Brewster also read a commu- 
nication to this Society in 1820, on the occurrence, in some 
diamonds, of a polarising structure, occasioned by the ex- 
istence within them of small portions of air, “the expansive 
force of which has communicated a polarising structure to 
the parts in immediate contact with the air.’ This struc- 
ture, Sir David thinks, “can arise only from the expansive 
force exerted by the included air on the diamond, when it 
was in such a soft state as to be susceptible of compression 
from so small a force. That this compressible state of the 
diamond could not arise from the action of heat, is mani- 
fest from the nature and recent formation of the soil in 
which it is found: that it could not exist in a mass formed 
by aqueous deposition, is still more obvious; and hence we 
are led to the conclusion, rendered probable by other analo- 
gies, that the diamond originates, like amber, from the con- 
solidation of perhaps vegetable matter, which gradually ac- 
quires a crystalline form by the influence of time and the 
slow action of corpuscular forces.”* 
Sir David Brewster and Liebig are thus, to some extent, at 
issue. The latter thinking “that there is the greatest rea- 
son to believe that diamonds are formed in the humid way ;” 
the former contending that “ they cannot have been formed 
by aqueous deposition.” 
“In extension of these speculations, I would suggest the’ 
probability of anthracite being one of the substances most! 
likély 'to erystallise into the diamond. It does not'seem‘ne- 
cessary, however, to adopt Sir Dayid’s view, that the diamond 
* Edin, Phil. Jour., 1820, pp. 99-1005 415 54 
