288 
Messrs. Allen and Pepys on the 
Second Experiment on animal Charcoal. 
Thermometer 59 0 Fahrenheit, barometer 29,45. 
Some of the animal charcoal of last experiment was heated 
to redness under sand for one hour. 4 grains were placed in 
the platina tray ; and as we were so much embarrassed in the 
last experiment with the saline matter which adhered to the 
tray, we exactly balanced it with its contents. Ouroxygene, 
made as usual, left a residuum of 2 parts in 100, and we began 
with 49,84 cubic inches. When every thing was adjusted, and 
the platina tube red hot, on passing the oxygene, flashes resem- 
bling lightning ran along the glass tube ; and this was repeated 
5 or 6 times. The whole of the gas became very cloudy, ex- 
hibiting a turbid milky appearance. The tube was rendered 
white hot by the combustion of the carbonaceous matter in 
oxygene. The fire was kept up about 8 minutes, and the gas 
passed several times. When all was cool, we could observe 
no alteration in the volume of gas by the register. The tray 
contained a mixture of salts ; and being weighed, was lighter 
by 3,2 grains. This loss was not wholly carbon, for it is well 
known that animal substance contains a variety of salts, as 
phosphates, muriates, &c. some of which, though not volatile 
in a low red heat, might be decomposed and dissipated in the 
intense white heat produced by the combustion of the car- 
bonaceous matter in oxygene ; and we accordingly found the 
internal parts of the gasometers and tubes very slightly co- 
vered with a sort of efflorescence. On examining the gas after 
the experiment, 
