148 MINERAL TAR. 
very deep pit. The petroleum was at first found to ooze 
from between the crannies of the rock, but it soon af- 
terwards poured forth in a considerable stream. The 
utility of this fluid having been made known, large iron 
pipes were formed from the spring into pits sunk for the 
purpose of receiving it. From these pits it is conveyed 
into immense caldrons, where it is boiled until it attains 
the consistency of pitch. Since the first discovery of 
this substance, three different springs of it have broken 
out. One of these is near the celebrated iron bridge; 
and the fluid that issues from it is almost pellucid, but, 
at the same time, is thicker than treacle. 
Petroleum easily takes fire, and, in burning, yields a 
strong, sharp, and somewhat unpleasant odour ; and a 
thick and disagreeable smoke. In cold weather it con- 
geals in the open air. 
In Pegu, and other parts of the East, petroleum is 
used in place of oil for lamps. Boiled with a species 
of resin, it is employed for painting the timber of 
houses, and covering the bottoms of "boats and other 
vessels. In the latter respect it is considered to be 
particularly efficacious, by protecting the timber from 
the attacks of marine worms. It is also used by the 
inhabitants of eastern countries as a lotion in cutaneous 
eruptions, and as an embrocation in bruises and rheu- 
matic affections. The ancient Egyptians used it in the 
embalming of dead bodies. In some countries lumps 
of earth are soaked with petroleum, and are employed 
as fuel. 
214. MINERAL TAR, or BARBADOES TAR, is a 
fluid kind of bitumen, somewhat thicker than petroleum, and 
nearly of the consistence of common tar. It is viscid, of a 
Hack, brownish black, or reddish colour. 
In burning its smell is disagreeable, but less pungent than 
that of most other kinds of bitumen. Its weight is somewhat 
greater than that of water. 
In the West ladies, where this substance is princi- 
pally found, it is applied to many of the purposes for 
which the preceding species is used ; but its principal 
