Anniversary Address. 13 



M. Pavre shows, that of thirty-four roiner'als found with 

 Piamond (according to the catalogue of M. Denis), consisting 

 of sulphurets, carbonates, oxides, silicates, and native metals, 

 thirty have been artificially produced ; and of the thirty, 

 twenty-nine were produced by the aid of volatile chlorides. 



If this be the case, though one of the conditions is heat, the 

 argument as to an igneous origin for Diamond, because it is 

 found in association with minerals of igneous origin, must be 

 abandoned or modified. 



Ten years later, Professor Goppert, in his work " On the 

 Organic Nature of the Diamond," pointed out, as Jaquelain had 

 done, that it may be turned into coke. He says, that some must 

 have been soft, as they are superficially impressed by sand and 

 crystals ; that others contain crystals of other minerals, germs 

 of plants and fragments of vegetation. Hence, it wou'd 

 certainly appear, that the origin of such Diamond s cannot have 

 been igneous, and, I may add, assuredly not more so than those 

 granitic rocks I have already mentioned, that contain Coal 

 measure plants. He states further, in 1868, that he had a 

 Diamond which contained dendrites, such as occurs on minerals 

 of aqueous origin ; that there are at Berlin, one which contains 

 bodies resembling Protococcus j^^uvialis, and another green 

 corpuscles linked together, closely resembling PalmogJcea macro- 

 cocca. To these supposed Algse the names have been given of 

 P. adamantinus and Palmogleites adamantimis. As illustrating 

 the views he takes of these Diamonds, he says, the Metamorphic 

 rocks in which vhey occur also contain evidences of vegetable 

 fossils, such as Eozocn canadeni,e ; and that even in some topazes 

 there are traces of organic substances. 



A very interesting lecture was delivered by Dr. Percy, On 

 Chemical Geology, on 12th December, 1863, before the School of 

 Mines, in which he treats of the formation of Silica ; of " that 

 glorious mineral Corundum^'' of Spinel, and of other gem- 

 stones ; showing the influence of water, moderate heat, and 

 salts of chromium, and he then adds : '* the Diamond will come 

 ultimately, no doubt." There is nothing to show that an 

 igneous origin is attributed to them. 



