1879.] Native Bitumens and the Pitch Lake of Trinidad. 241 
nature has been so grossly misrepresented as the Pitch Lake of 
Trinidad. In an official history of the English Exposition of 
1851, under the head of descriptions of articles from Trinidad, it 
is stated that, “The Pitch Lake is on the highest land in the 
island. It is soft and fluid at the center, and there is an active 
submarine volcano near the coast.” I have already given the 
true altitude of the lake as one hundred and forty feet, while the 
highest point on the island is Mt. Tucutche, 3100 feet above the 
sea. The submarine volcano is a petroleum spring which comes 
up under the water a short distance from shore; the water is 
visibly oily over an area of several rods, and bubbles of gas are 
sometimes seen to escape, but nothing farther, though another 
writer speaks of this as “a submarine volcano which at times 
makes a noise like thunder and emits naphtha and petroleum.” 
The lake itself is usually described as three miles in circumfer- 
ence, hot and fluid in the center, but cold and solid toward the 
shore. In point of fact this body of pitch, which is of approxi- 
mately circular outline, is scarcely one and one-half miles in cir- 
cuit, and there is no part of its surface that may not be walked 
upon with impunity. The temperature is uniform throughout. 
The area of the lake is ninety-nine acres. Its surface, soft enough 
in a few spots to receive the impression of a man’s boot, is for the 
most part quite hard and firm, and everywhere of a dull earthy- 
brown or brownish-black color. The fracture is eminently con- 
choidal, but the lustre is always dull, the result of an admixture 
of twenty to thirty per cent. of earthy matter, sand and clay. 
These impurities are removed by boiling, and the pitch then 
becomes shining black and still more brittle. 
There are some twenty or more patches on the lake, five to 
_ fifteen yards in diameter where soil has collected and vegetation 
—trees, shrubs and grasses—has gained a foothold, forming green 
islands or oases. The surface presents many small dome-shaped 
swellings or protuberances, from an inch to a foot in diameter; 
these pitch bubbles are always hollow, and contain traces of the 
lighter portions of vegetation in a half decayed state, the thin 
covering appearing to have been raised by gases given off from- 
the decomposing leaves and twigs, or liberated by the sun’s heat 
from the pitch itself, Excavations made in the pitch show that 
below the surface these cavities or vesicles are exceedingly 
numerous; they are usually — or 7. being 
VOL. XIII.—No. ty. 17 
