146 
nensis. These springs have also been noticed by Frassoni, in 1660, 
in a pamphlet entitled Thermae Montis Gibii; by Ramazzini, in 1698 j 
and by Vallisneri, in 1^1 1. 
Bituminous substances in various degrees of solidity and purity 
are found in several parts of England ; as is indeed the case in most 
parts, in the neighbourhood of which coals are found to exist. 
Dr. Plott, in a discourse concerning perpetual sepulchral lamps, 
read before the Dublin Society, 1684*, mentions that at Pitchford, 
in Shropshire, there is a naphtha or liquid bitumen, that constantly 
issues forth with a spring there, and floats upon the water. This, 
the Doctor thinks, might be separated, before it joins the water, into 
a channel of its own ; and so conveyed to a place thought most con- 
venient for such a lamp, into which it should perpetually distil, as 
it does now into the fountain. For, the Doctor observes, a brush 
or wick of asbestos, or of gold wire, might be employed, and if the 
oil be properly disposed, then, says the Doctor, we have an oil as 
everlasting as our wick; nor need we fear any extinction, if en- 
closed in a tomb or vault under ground, in never so damp and 
moist a place ; it being, he adds, the characteristic of bitumen, to 
burn best where there is moisture, as is evident upon affusion of 
water upon sea coal. 
Among the inflammable minerals of Derbyshire, Mr. Mawe, 
whose opportunities of observation are as great, as his collection is 
interesting, observes, the most remarkable is the elastic bitumen, 
in its various statesf. It is generally, he says, found between 
the stratum of schistus and lime-stone ; rarely in small cavities, 
adhering to the gangart, which sometimes contains lead ore, fluor, 
&c. When first detached, its taste is very styptic, as if blended 
with decomposed pyrites. It varies in colour, from the blackish 
* Mr. Ayscough’s Catal. 4811. Plut. vi. E. vol. i. 34, 1684. 
f The Mineralogy of Derbyshire, by John Mawe, p. 92. 
