the lake to the sea, by the process of expansion by day and
contraction by night, and may be likened to a caterpillar, or rather
caterpillars innumerable, progressing by expanding and contracting
their rings, having strength enough to crawl down hill, but not
strength enough to back up hill again.

At last we surmounted the last rise, and before us lay the famous
lake--not at the bottom of a depression, as we expected, but at the
top of a rise, whence the ground slopes away from it on two sides, and
rises from it very slightly on the two others. The black pool glared
and glittered in the sun. A group of islands, some twenty yards wide,
were scattered about the middle of it. Beyond it rose a double forest
of Moriche fan-palms; and to the right of them high wood with giant
Mombins and undergrowth of Cocorite--a paradise on the other side of
the Stygian pool.

[Illustration: THE PITCH LAKE.]

We walked, with some misgivings, on to the asphalt, and found it
perfectly hard. In a few steps we were stopped by a channel of clear
water, with tiny fish and water-beetles in it; and, looking round, saw
that the whole lake was intersected with channels, so unlike anything
which can be seen elsewhere that it is not easy to describe them.

Conceive a crowd of mushrooms, of all shapes, from ten to fifty feet
across, close together side by side, their tops being kept at exactly
the same level, their rounded rims squeezed tight against each other;
then conceive water poured on them so as to fill the parting seams,
and in the wet season, during which we visited it, to overflow the
tops somewhat. Thus would each mushroom represent, tolerably well, one
of the innumerable flat asphalt bosses, which seem to have sprung up
each from a separate centre, while the parting seams would be of much
the same shape as those in the asphalt, broad and shallow atop, and
rolling downward in a smooth curve, till they are at bottom mere
cracks from two to ten feet deep. Whether these cracks actually close
up below, and the two contiguous masses of pitch become one, cannot be
seen. As far as the eye goes down, they are two, though pressed close
to each other. Messrs. Wall and Sawkins explain the odd fact clearly
and simply. The oil, they say, which the asphalt contains when it
rises first, evaporates in the sun, of course most on the outside of
the heap, leaving a thorough coat of asphalt, which has, generally, no
power to unite with the corresponding coa