316 Dr. Davy on the Geology and Mineralogy of Ceylon . 
tured in the Kandian country. I have visited two spots of this kind, 
and I have examined specimens from two more, and on these grounds 
I have formed my opinion. In relation to this rock, I shall notice 
only the principal nitre work that I have seen, and which I under- 
stand is the most extensive belonging to the natives. It is a large 
cave in the side of a great precipice, which is situated in the depth 
of an immense forest surrounded by mountains in a remote part of 
Doonberava. The cave is about 200 feet deep, and its mouth is 
about 100 feet high by 80 feet wide. The rock in which it occurs 
is an intimate mixture of quartz, felspar, calcareous spar, and mica, 
with here and there talc and some other minerals. Wherever it is 
exposed to the air, the rock is impregnated with nitre ; and not 
merely at the surface, but as deep as air can penetrate, but no further. 
Besides nitre, I may remark, the rock contains other salts, as nitrate 
of lime, sulphate of magnesia, and alum. Were it not foreign to 
the general account to which I have proposed to confine myself, I 
could give you further particulars respecting this interesting cave, 
and respecting the Kandian workmen and their mode of making 
saltpetre ; you would be surprised at the rude apparatus they em- 
ploy, the degree of skill they shew on some points, and the profound 
ignorance on others ; how they sagaciously add wood ashes to de- 
compose the nitrate of lime, and how, after being at great pains to 
purify the nitre by picking out the crystals of sulphate of magnesia, 
they ignorantly throw away this latter salt : nor w r ould you be a 
little struck by the savage persons of these men, their bodies almost 
naked, their matted hair and long beards, with minds corresponding 
to their forms, superstitious in proportion to their ignorance, as is 
exemplified in their sacrificing to Demons, and offering them their 
best refined nitre to propitiate favour : but I digress beyond my 
intention. 
