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324 Count de Bournon’s Description of 
Secondly, That the appearance of this substance was entirely 
different from that of felspar ; and that, where it came in contact 
with the felspar, it seemed to mix itself with it in such an in- 
sensible manner, that, after having sawed and polished a piece 
composed partly of felspar and partly of the substance here 
spoken of, it was impossible, by the eye, to distinguish exactly 
where the felspar began, or, which is the same thing, where the 
other substance terminated. 
Thirdly, I find also by my notes, that the pieces I had col- 
lected, varied considerably in their degree of hardness, although 
all of them were harder than felspar usually is ; for many 
of these pieces would scarcely scratch felspar ; whereas others 
could scarcely be scratched by the greatest number of gems 
or precious stones. The characters of the last mentioned or 
hardest pieces, appeared to me to be very similar to those of 
the imperfect corundum from China, a crystal of which Rome' 
de Lisle had sent me a short time before. The above obser- 
vations, joined to the remarkable manner in which this sub- 
stance is mixed with felspar, made me adopt the erroneous 
opinion mentioned by the Abbd Hauy, in his observations upon 
corundum, namely, that this substance might be nothing more 
than a more dense variety of felspar. I soon, however, entirely 
gave up this idea, after I had it in my power to examine more 
particularly the nature of corundum. 
Fourthly, and lastly, I find by my notes, (and I also remem- 
ber it perfectly well,) that among the pieces I was able, by pa- 
tiently and carefully using the tools employed for that purpose 
by mineralogists, to extract from the vein above mentioned, 
there were some to which adhered small irregularly shaped 
pieces of a substance that was perfectly transparent, and had 
