138 AY. Harenerr’s. Obfervations on Bituminous Subjlances. 
BITUMINOUS WOOD, as well as of ‘CURF and PEAT. 
E1rumtnovs or foffil wood is found in many places; but in re+ 
fpect to that which is found at Bovey, near Exeter, and which is 
therefore called Bovey coal, there are fome peculiarities which de- 
ferve to be menticned. The Bovey coal is a dark brown, light, 
brittle fubftance, which ia texture and other external properties 
muclt refembles wood which has been half charred. It is not 
found as feattered logs or trunks, but forms regular ftrata. 
The pits are on a heath which is flat and fandy 3 the ftratum of 
fand is however but thin, atter which a pale brownith grey clay is 
found mixed with quartz pebbles. This prevails to about fix feet, 
at which depth the firft ftratam of the coal commences. The 
quality of this is however much inferior to that of the fubfequent 
ftrata, which in all amount to feventeen, producing a depth of 
nearly feventy-four feet from the furface. Between each ftratum 
of coal is a ftratum of clay. The direétion of the ftrata is from eaft 
to welt, and the inclination or dip is from north to fouth. The 
inferior ftrata are thought to afford the beft coal, and the coal is 
more folid and of a better quality towards the fouth. The thickeft 
ftratum of coal is from fix to eight feet *. 
The Bovey coal burns readily with a flame like half charred ita: 
it does not crackle, and, if but moderately burned, forms charcoal; 
or if completely burned, it leaves a {mall quantity of white afhes 
exactly fimilar to thofe of wood. The fmell of it-when !burn- 
ing alfo refembles that of wood, with a faint difagreeable odour. 
It is certainly very remarkable that this fubftance fhould form 
regular ftrata, although it poffeffes the texture and moft of the 
* In the winter, twelve men can raife about 120 tons of this coal ina 7 a 
whole of which is employed ina neighbouring Pottery. 
* properties 
