PETROLEUM. 147 
many persons, from different parts of the adjacent 
country, came to visit what was called the " burning 
well." To prevent this spring from being destroyed, 
an iron cistern was placed upon it, with a small hole 
in the cover, through which the water might be viewed. 
When a lighted candle was put into this hole, the water 
immediately took fire, darting and flashing in a violent 
manner, much in the same way as spirits do in a lamp, 
but with greater agitation. It would sometimes burn 
for forty-eight hours successively, and without any 
sensible diminution : and a tea-kettle, full of water, by 
being placed upon the hole, has been made to boil in 
nine minutes. In 174-7, this spring had been lost for 
many years; but another was shortly afterwards dis- 
covered, the issuing of which was announced by a 
rumbling noise under ground, similar to that which 
had been formerly heard. This, however, also disap- 
peared in the year 1756, by the sinking of a coal-pit in 
the neighbourhood. 
213. PETROLEUM, or MINERAL OIL, is a fluid 
bitumen, of' somewhat greater consistency than naphtha : of 
Hack, brozon, or sometimes dingy green colour. 
By exposure to the air it assumes the consistence of tar, and 
is then called MINERAL TAR (214). 
This substance exudes spontaneously from the earth, 
or from clefts of rocks, and is found in nearly all coun- 
tries, particularly in the East Indies, Italy, France, 
Spain, Germany, and England. In the neighbourhood 
of Rangoon, in Pegu, there are several hundred wells of 
petroleum. These are of square form, of considerable 
depth, and each lined with cassia wood staves. The oil 
is drawn from them pure, and in a liquid state, and is 
conveyed thence in small jars. The whole annual pro- 
duce of this district is estimated at more than 400,000 
hogsheads. 
At Colebrook Dale, in Shropshire, there is a spring 
of petroleum. This was discovered at the depth of 
about thirty yards beneath the surface of the earth, in 
digging an archway for the conveying of coals from a 
H 2 
