240 Count de Bournon's Description of 
place it nearer those stones with which, from their possessing 
those two qualities, it seemed to have some analogy. Perhaps 
he was not in possession of specimens of sapphire, or of ori- 
ental ruby, or of corundum, sufficiently characterised to serve 
as objects of comparison ; and I cannot help expressing great 
regret, that the crystals of corundum which were sent to him 
by Mr. Greville, selected by myself from his superb col- 
lection, and to which I had the pleasure of adding an almost 
equal number from my own, were not sufficient to carry con- 
viction to Mr. Hauy's mind; as it would have given me great 
satisfaction to find that my observations, upon this interesting 
substance, perfectly coincided with his. The opinion of a na- 
turalist so justly celebrated as Mr. Hauy, will naturally have 
great weight in the minds of those who pursue the study of 
mineralogy ; for which reason, after giving a particular descrip- 
tion of corundum, comprehending all the characters which are 
peculiar to it, I shall endehvour to remove every objection which 
this mineralogist still thinks it right to offer, against its union 
with the sapphire, oriental ruby, &c. 
The substance here treated of, has hitherto presented itself to 
our notice under two appearances, which differ so much from 
each other, in the greater number of those characters which 
most forcibly affect our senses, particularly those which concern 
the organ of sight, that we cannot be much surprised to find 
that mineralogists feel some reluctance, at the idea of uniting 
together substances which appear so very dissimilar. 
Under one of these appearances, in which it is known by the 
name of corundum, this substance presents itself either in frag- 
ments, or in crystals of a pretty large size ; sometimes, indeed, 
of a very considerable one. The surface of these crystals is 
