lis Iiiielligence and Miscellaneous Articles. 



that in which silicaisdepositedin the joints of certain arundinaceous 

 vegetables. And Dr. Brewster, at a later period, (See Edin.Phil. 

 JoLirn. vol. iii. p. lOJ.) from the very compressible state which 

 certain optical characters of the diamond evince it to have once 

 possessed, and which, he states, could not arise from the action of 

 heat, nor exist in a mass formed by aqueous deposition, inferred, 

 that the diamond probably originates, like amber, from the conso- 

 lidation of perhaps vegetable matter^ which gradually acquires a 

 crystalline form. 



It is not intended, in the present remarks, to advocate the opi- 

 nion either of Professor Jameson or Dr. Brewster, though, under all 

 the circumstances of the case, both are deserving of attention ; but 

 Mr. Voysey quotes the observations of the latter writer, with the 

 intent to prove, that, as " diamonds have for two centuries at least 

 been found in a rock, generally supposed to owe its origin to depo- 

 sition from water," his inference can apply, only, to the diamonds 

 found in alluvial soil. It is unnecessary to show, that if Mr. V. had 

 really discovered the matrix of the diamonds, the same origin must 

 have been attributed to those specimens which occur in alluvial 

 soils ; but as the rock in which he states the diamonds of Southei'n 

 India are I'ound, consists of the re-united debris of former rocks, 

 his observations throw no further light on the history of this 

 substance, than as indicating, perhaps, as the breccia is probably 

 one of great antiquity, that this form of carbon existed at an early 

 period in the formation of the present crust of the earth. This, in- 

 deed, we may likewise infer, perhaps, from the matrix of the diamond 

 mentioned by Mr. Heuland. It might also be concluded from that 

 specimen, that the diamond is an original production of the mine- 

 ral kingdom. Still, however, this cannot be decided from a single 

 instance of its occurrence in a mineral vein ; and the remarkable 

 analogies between amber and the diamond, discovered by Dr. 

 Brewster, besides that already mentioned, certainly entitle his 

 opinion on its origin to philosophical examination. It must be re- 

 marked, at the same time, that when Dr. Brewster published his 

 observations, the diamond had been found only in alluvial deposits; 

 but the discovery of it in a matrix of ironstone, (if confirmed by 

 future discoveries,) and also in a breccia of ancient formation, re- 

 moves Dr. B.'s objection to supposing the former compressible state 

 of the diamond to have arisen from the action of heat, which is de- 

 duced merely '■'■from the nature and the recent formation of the soil" 

 in which onl}', at the time his paper appeared, it had been found. 



Peihaps the opinions on this subject of Professor Jameson and 

 Dr. Brewster are not incompatible with each other ; and if the 

 diamond were really produced in a manner resembling that in which 

 Tabasheer is formed, we might expect to find some analogies in the 

 physical structure of the two substances ; though, on the other hand, 

 the absence of such analogies would not negative the proposition, as 

 the chemical nature and functions in the vegetable world of carbon 

 and silica are so widely different. Dr. Brewster has examined the 

 structure of Tabasheer ; but whether it exhibits any analogies to 



that 



