402 Mr. Hatchett’s Observations on the Change 
of it, and therefore contented myself with briefly describing it, 
in a note annexed to my Paper on bituminous Substances.* 
Lately, however, my friend John Sheldon, Esq. of Exeter, 
F. R. S. obligingly sent me several pieces of it, together with 
specimens of the different kinds of Bovey coal which have been 
mentioned; and thus I was enabled fully to ascertain its real 
nature and properties. 
DESCRIPTION OF THE BITUlMEN FROM BOVEY. 
It accompanies the Bovey coal, in the manner already de- 
scribed, and is found in masses of a moderate size. 
The colour is pale brownish ochraceous yellow. 
The fracture is imperfectly conchoidal. 
It appears earthy externally, but, when broken, exhibits a 
slight degree of vitreous lustre. 
The fragments are irregularly angular, and completely opaque 
at the edges. 
It is extremely brittle. 
It does not apparently become softened, when held for some 
time in the hand, but emits a faint resinous odour. 
The specific gravity, at temperature 65° of Fahrenheit, is 
M35- 
Some specimens have dark spots, slightly approaching in 
colour and lustre to asphaltum ; and small portions of the Bovey 
coal are commonly interspersed in the larger masses of this 
bitumen. 
When placed on a heated iron, it immediately melts, smokes 
much, burns with a bright flame, and yields a very fragrant 
odour, like some of the sweet-scented resins, but which at last 
becomes slightly tainted with that of asphaltum. 
* Transactions of the Lin nean Society, Vol. IV. p. 139. 
