of some of the Principles of Vegetables into Bitumen , &c. 403 
The melted mass, when cold, is black, very brittle, and breaks 
with a glossy fracture. 
EXPERIMENTS. 
A. 100 grains of this bitumen, when distilled until the bulb 
of the retort became red-hot, afforded. Grains. 
1. Water slightly acid - - 3 
2. Thick brown oily bitumen, very similar to that which 
was obtained from the Bovey coal, but possessing 
slightly the odour of vegetable tar - 45 
3. Light spongy coal - - - - 23 
4. Mixed gas, composed of hydrogen, carbonated hydro- 
gen, and carbonic acid, (by computation,) - 29. 
The coal yielded about three grains and a half of ashes, 
which consisted of alumina, iron, and silica, with a trace of lime. 
B. The bitumen was not affected by being long digested in 
boiling distilled water. 
C. By digesting 100 grains in lixivium of pure potash, a 
brown solution was formed ; this was saturated with muriatic 
acid, and a brown resinous precipitate was obtained, which 
weighed 21 grains. 
D. A portion was digested in nitric acid : at first, much 
nitrous gas was evolved, and, after the digestion had been con- 
tinued for nearly 48 hours, a part was dissolved, and formed 
an orange-coloured solution, which did not yield any precipi- 
tate, when saturated by the alkalis, or by lime; the colour only 
became more deep, and, by evaporation, a yellow viscid sub- 
stance was obtained, which was soluble in water. The above 
nitric solution possessed every property of those nitric solutions 
of resinous substances which I have mentioned in a former 
Paper.* 
* Phil. Trans, for 1804, p. 198. 
