/ 
the Corundum Stone, a?id its Varieties , &c. 321 
dum ; other parcels which contained only a very small quan- 
tity ; and others in which the proportion of that substance was 
pretty considerable : the same remark may be applied to every 
one of the other substances. It is therefore, I think, fair to 
conclude, from the above circumstances, that these sands come 
from different rivers or rivulets, or, if from one river only, from 
one into which other rivers discharge themselves ; and that the 
nature of the sand varies, according to the particular circum- 
stances which may have caused one or more of those rivers to 
bring down a greater, and others a less proportion, of the sub- 
stances of which it consists. It may indeed also be asked, if what 
is called the sand of Ceylon comes exclusively from that island ? 
To this question, I can give no decisive answer. I shall only 
observe, that the length of time it has gone under that deno- 
mination, without any alteration, gives some reason for thinking 
it has really some claim to it. 
It is, at this time, a doubtful point, whether corundum is found 
in any part of the world, besides certain districts of the East 
Indies ; although, as will presently be seen, I have strong 
reasons for thinking that it also exists in one of the mountain-* 
ous provinces of France. 
I have seen many specimens which were sent from Ger- 
many, under the name of corundum ; some of them were nothing 
more than felspar of a brownish red colour ; others were the 
stone called schorlartiger beryl, by Werner, (the pycnite of the 
Abbd Hauy,) but in pieces which were rather less striated than 
is usually the case with respect to that stone. 
It was thought, for some time, that a stone found at Tiree, on 
the eastern coast of Scotland, was of the nature of corundum. 
i 
