the Corundum Stone , and its Varieties , &c. 
305 
hardness and their lustre, are considered as of value in com- 
merce, deprives us of all chance of obtaining that knowledge 
respecting the matrix here treated of, which might otherwise be 
acquired, from an attentive examination of the various substances 
which it is natural to suppose are brought down, with the sand, 
by the streams. We shall, however, presently see, that one of 
those fortunate events by which nature sometimes rewards the 
labours of those who devote themselves to the studv of her 
works, has presented us with some very interesting facts on this 
subject. 
In order to render as complete as possible, every information 
which is connected with the investigation of corundum in ge- 
neral, and particularly to make known every thing I have 
been able to learn respecting this stone in its highest degree 
of perfection, I think it right to make some remarks on the 
various substances with which it is accompanied, in the sand 
sent to us from Ceylon ; although I cannot undertake to assert 
positively, that these substances really accompany it, when in 
its matrix. 
Spine lie. The first of these substances, and one which com- 
poses more than nine parts in ten of the whole mass of the 
sand, is the spindle ruby, now generally known by the name of 
spinelle. Notwithstanding the great number of crystals of this 
substance which are found in the sand, it is very uncommon to 
meet with one of a tolerable size, that is both transparent and 
of a pet feet form : indeed most of them are merely fragments, 
dhe selection that has already been made in India, where 
these stones receive their first polish, in order to be distributed 
for sale, is no doubt the chief reason of the above circumstance : 
