438 New Facts concerning the Diamond. [October, 



even undecided whether the diamond is of igneous or vege- 

 table origin, whether its nature is mineral or organic : some 

 diamonds appear to have been soft, as they are superficially- 

 impressed by sand and crystals ; others contain crystals of 

 other minerals, germs of plants, and fragments of vege- 

 tation. Professor Goppert has a diamond containing den- 

 drites, such as occurs on minerals of aqueous origin ; and 

 there is at Berlin a diamond which contains bodies resem- 

 bling Protococcns pluvialis, and another containing green 

 corpuscles linked together closely, resembling Polinoglcea 

 macrococca. Sir John Herschel quotes the case of a Bahia 

 diamond, mentioned by Harting, which contained well- 

 formed filaments of iron pyrites. Messrs. Sorby and Baker 

 have shown that the diamond may contain cavities entirely 

 or partially filled with a liquid, probably condensed carbonic 

 acid, and that the black specks in diamonds are really 

 crystals which are sometimes surrounded by contraction 

 cracks, a black cross appearing under polarised light. Sir 

 David Brewster has likewise pointed out that the diamond 

 possesses strata of different refractive powers. M. Damour 

 states that diamonds sometimes contain spangles of gold in 

 their cavities. 



The latest researches published relative to the diamond, 

 namely, those of M. Schrotter and M. G. Rose have 

 furnished results which in some respects correspond neither 

 with each other nor with the facts already known to science. 

 M. E. H. von Baumhauer has instituted some experi- 

 ments on the subject, special attention being paid to the 

 different states in which the diamond occurs in nature. 

 This talented experimentalist having courteously placed a 

 copy of his research at our disposal, we are enabled to give 

 the most important of his results in these pages. In the 

 first place it was proposed to ascertain the density of the 

 diamond in each of its natural states, afterwards to study its 

 behaviour at high temperatures in the presence of various 

 gases, and lastly to attempt the decision of a point as yet 

 unsettled, namely, the possibility of its transformation by 

 means of heat, into graphite or amorphous carbon. The 

 materials necessary for experimentally pursuing these in- 

 quiries were furnished by the liberality of M. Alexander 

 Daniels, the talented manager of the diamond-cutting esta- 

 blishment at Amsterdam, belonging to M. Martin Coster, of 

 Paris. 



The condition of a more or less perfect crystal, trans- 

 parent and colourless, or nearly so, is by no means the only 

 one under which the diamond is found, although for some 



