on the Newry pitch-stone , &c. 335 
I have made pumice in an open crucible, and with the un- 
powdered stone, by watching the degree of heat. 
Magnetic properties . 
A needle, drawn a little out of the direction of the poles 
by a piece of iron, was drawn back by all the pitch-stones, 
and by pumice, natural and artificial. 
The pumices, as well the natural as the artificial, and the 
latter, whether obtained by distillation in glass or iron, were 
attracted, when in powder, by the magnet ; but the magnet 
did not act on any of the pitch-stones under any circum- 
stances. 
RESULT. 
If the foregoing analysis is correct, that variety of the 
Newry pitch-stone which I examined contains in one hundred 
parts, 
Silica .... 
72,800 
Alumine . 
11,500 
Lime 
1, 12 
Protoxide of iron . 
3,036 
Soda 
2,8 57 
Water and bitumen 
8,500 
- 
99,813 
The Newry pitch-stone is a marked variety of that substance. 
It exists in various forms, and the bitumen in various pro- 
portions in the same vein. 
It contains, as far as at present appears, a peculiar bitumen. 
That bitumen exists in the Newry pitch-stone in a larger 
proportion than in any substance of that class hitherto ex- 
amined. 
