Mr. Greville on the 
418 
The Corundum of China. 
Argillaceous earth 
84 
O 
Siliceous earth 
6 
50 
Oxide of iron 
7 
50 
Loss 
Q 
O 
IOO 
That the analysis of sapphire by Mr. Klaproth may be com- 
pared, it is here added. 
Argillaceous earth 98 50 
Calx of iron - - - 1 o 
Calcareous earth - o 50 
■ 1 11 
100 
Iron ore crystallized is often mixed with the Chinese Co- 
rundum, as I have before stated, and may be considered as 
accidentally interposed, not combined. In the Corundum of 
the Coast, the greenish colour may indicate the combination of 
iron, as the blue colour does in the sapphire ; and the propor- 
tion of iron in both is nearly alike. 
There then is the and of silex in Corundum, evi- 
dently an integral part of the coarse Corundum crystal, and 
not of the sapphire; but it will require an analysis of the vitreous 
or pellucid Corundum, to decide that silex is a constituent part 
of Corundum : there will then remain to account for the calca- 
reous earth; and, having established its being a constituent part 
of the sapphire, the small proportion of —- 5 , cannot be expected 
to produce a very notable difference. 
It is not necessary to do more than thus to hint at what 
further analysis and examination of former experiments are 
