97 
T he same thing happened not long ago at Whitehaven, and in the neigh¬ 
bourhood of Halifax. 
In the month of September, 1/^51, the Cliffs near Charmouth in Dorset¬ 
shire, took fire, in consequence of a heavy fall of rain after a hot and dry 
season, and they continued at intervals to emit flame for several years. 
These cliffs consist of a dark-coloured bituminous loam, in which are im¬ 
bedded large quantities of different kinds of the pyrites. 
The same kind of flame has been frequently observed in the Cornish 
mines, and has often led to the discovery of the treasures in the earth; for 
wherever this has existed minerals, especially the pyrites, have universally 
been found. 
1 « i 
There are some sorts of earth from which alum is made, which abound 
so much with pyrites that the proprietors of these works are forced to keep 
them constantly deluged with water, in order to keep them from firing. 
But it seems useless to pursue this subject further; we have adduced 
proofs sufficient, that nature furnishes materials, which, under certain circum¬ 
stances, may become the occasion of subterraneous fires. 
The requisite circumstances are a proper quantity of the materials, and a 
proper proportion of water to moisten them. 
A small quantity of the pyrites is sufficient to kindle a fire; water is al¬ 
most every where found in such great plenty below the surface of the earth, 
that it constitutes one of the greatest impediments to our sinking pits to any 
great depth; and air, if it should be thought absolutely necessary to the spon¬ 
taneous firing of the pyrites, may be conceived either to accompany the water 
in its dripping, or to descend into the innermost parts of the earth through 
fissures which are found upon its surface. 
When a subterranean fire is once kindled, it may be supported for ages 
by other substances, as well as by those which first gave rise to it; thus if a 
quantity of the pyrites should take fire in a stratum of coal, or of shale, or any 
other substance strongly impregnated with bitumen, the fire might continue 
till the stratum was consumed. 
There are some coaleries on fire now in Scotland, which were on fire in 
the time of Agricula (Pennant’s Tour in Scot. p. 201). See an account of 
the coaleries on fire in Staffordshire, in Dr. Plott’s Natural History of that 
2 B 
