12 Annivermry Address, 



drift, and of necessity of the gold drifts, Jfiiviatile ov glacial? A 

 marine accumulation is not suggested ; and no fossil remains, 

 favouring such a solution of the question, have been found. 

 Silicified wood of the Carboniferous age occurs abundantly in 

 the drift ; but it must have been silicified long before any 

 Dianond could have been formed fiom the cai'bon which 

 the original wood contained, unless Diamonds claim an 

 antiquity as high as that of the Coal measures themselves, 

 or even one higher than theirs. In that case, they 

 must also be drifted, as well as the minerals and rocks that are 

 associated with them. 



This may be the final result of our enquiries, but there are 

 many who (as Mr. Taylor does) think the Diamond is a product of 

 chemical forces now in operation, and therefore, it is a strictly 

 local and limited product, not necessarily connected with any 

 Carboniferous beds of comparatively high antiquity. As Magnesite 

 exists in the vicinity, and that is certainly a recent product, 

 arising from the decomposition of the exposed igneous rocks, so 

 infiltration, decomposition, and reconstruction of carbonaceous 

 materials, of whatever age, under the influence of chemical 

 transformation, may be producing Diamonds at this moment, 

 wherever the needful conditions exist. 



An author of some distinction, M. Tavre, Professor of Geology 

 at Greneva, has turned his attention to this very subject, and as 

 his paper " On Artificial Minerals " may not be generally 

 known, I will refer to it. [It is to be found in the " Bulletin^^ 

 of the " Socieie Qeologique de France,^'' vol. xiii., 2nd series.] 

 He therein reviews the experiments which, up to 1855, had been 

 made in the production of artificial Diamonds, and refers to the 

 experiments of M. Jaquelaiu who had procured from the 

 Diamond a carbonaceous matter having the aspect of coke, and 

 those of M. Despretz who had provec" that melted Carbon and 

 melted Diamond are nothing but graphite. This is akin to the 

 idea of Glocker of Breslau, and of others before him, that 

 Diamond is an altered coal. Petzholdt also found in diff"erent 

 Diamonds — especially the brown — traces of similar organisation 

 to that of silicified vegetable matter ; but Dufrenoy rejects the 

 opinion of Liebig, that they can have a vegetable origin. 



