322 Count de Bournon’s Description of 
But, after examining a specimen of that stone, which is in the 
British Museum, I found that its hardness, and its specific gravity, 
were both very inferior to those of corundum. In its exterior 
appearance, it very much resembles the felspar that accompanies 
the imperfect corundum from the Carnatic, and which I have 
already described, when speaking of the substances which ac~ 
company that kind of corundum in its matrix. 
It is also said that corundum has been found in America, at 
Chesnut Hill, near Philadelphia. But there are, in the Philo- 
sophical Magazine, No. 45, for February last, some observations 
made by Mr. Richard Philips, upon the external characters 
of the American stone, intended to show that it cannot pos- 
sibly be corundum. Mr. Philips has since told me, that the 
specimen upon which his observations were founded, was sent 
to him directly from Philadelphia, as a piece of the corundum 
found near that city. He also recalled to my mind, (which 
I had entirely forgot,) that he had shown me the specimen 
some time before ; and that I then gave it as my opinion, that 
the crystal it contained, supposed to be corundum, was nothing 
more than an ill- defined crystal of quartz. Nevertheless, Mr. 
Smith, a well-informed mineralogist, from America, has since 
assured me of the truth of the discovery of corundum, in the 
neighbourhood of Philadelphia. In that case, there must have 
been some mistake respecting the specimen that was sent to Mr. 
Philips. Upon the whole, there still remains some uncertainty 
with regard to the existence of corundum in the neighbourhood 
of Philadelphia ; and it is necessary, in order to remove all doubt 
on this head, either that some of the substance should be sent 
to us, or that some mineralogist in that country should give 
