PITCH LAKE OF TRINIDAD. 185 
The most abundant petroleum springs known are 
those on the river Irawadi, in the Birman Empire ; 
there being 520 wells in one locality, which yield an- 
nually 400,000 hogsheads of petroleum. 
Fluid bitumen oozes from the bottom of the sea, 
on both sides of the Island of Trinidad, and rises up 
to the surface of the water. According to Dr. Hol- 
lend, the petroleum springs of Zante are much in 
the same state as in the time of Herodotus. The 
principal pool is about 50 feet in circumference, and 
a few feet deep ; the sides and bottom of this and* 
the others are thickly covered with petroleum, which, 
by agitation, is brought to the surface of the water, 
and collected. The amount obtained is about 100 
barrels annually. 
The pitch lake of Trinidad is about three miles in 
circumference. The asphaltum is sufficiently hard 
in wet weather to support heavy weights, but during 
warm weather it is nearly fluid. It is intersected 
with numerous cracks filled with water, which some- 
times close up, leaving marks on the surface. When 
highly covered with soil, as it is in many places, good 
crops of tropical productions are obtained ; but, ow- 
ing to this covering of soil, it is said to be difficult 
to ascertain the boundaries of the lake. Large quan- 
tities of naptha are obtained on the shores of the 
Caspian. The inhabitants of the town of Badbree, 
a port on that sea, are supplied with no other fuel 
than that obtained from the naptha and petroleum, 
with which the adjacent country abounds. The nap- 
tha springs at Rangoon, Pegu, produce over 92,000 
tons per annum. Mr. Lyell supposes that bitumi- 
nous minerals are produced from vegetable substan- 
ces which have undergone certain transformations 
and chemical changes by the agency of subterra- 
neous fire. "The bituminous shales," he remarks, 
"so common in geological formations of different 
ages, as also many stratified deposites of bitumen 
and pitch, seem clearly to attest that, at former pe- 
Q2 
