ng morning we were on the
road to the lake, or rather on a stream of bitumen (now indurated) which
in former ages overflowed the lake. Indeed the bitumen beneath this road
seems still to be on the move, as shown by curvilineal ridges on its
surface, like waves receding from a stone thrown into water. The
appearance of the lake is most extraordinary. One vast sheet of bitumen
extends until lost amidst luxuriant vegetation. Its circumference is
full three miles, exclusive of the creeks, which double the extent. The
bituminous surface is of a dark brown, waxy consistence, except in one
or two places where the fluid still exudes; obviously this spring is in
full vigour beneath, for the whole surface of the lake is formed into
protuberances like the segments of a globe pressed together, having
hollows between filled with rain-water, which (except in the immediate
vicinity of the bituminous springs) is inodorous and without taste--an
extraordinary fact, showing that this bitumen is of a nature quite
different from that of pyrotechnic mineral or vegetable tar. In its dry
state it is quite insoluble in water, though when charged with essential
oil, as it exudes from nature's laboratory, it imparts a pungent and
unpleasant taste. A considerable quantity of gas bubbles up through
these bituminous springs, showing that decomposition is still active
amongst the materials whence it exudes. Some of the recent bitumen has
an odour resembling vegetable gum. Mr. Johnson, the very obliging
proprietor of a neighbouring estate, had the goodness to cause some of
his labourers and a cart to bring samples to the beach. Means of
transport, however, were so inadequate, that we had recourse to digging
the more impure pitch on the beach, in order to prosecute our trials for
its substitution as fuel. This bitumen, which had flowed upwards of a
mile from the lake, was combined with earthy and other substances which
it had encountered in its course. Various attempts have heretofore been
made to apply the bitumen to useful purposes, but without success, as we
may judge from the total abandonment of those trials and expectations
which for a brief period induced its shipment to England with a view to
its application to the pavements of London and other cities. All
excavation has consequently ceased, and so low is the estimation in
which the bitumen is held, that the duty on embarkation is only one
halfpenny per ton. The nature of this bitumen is very dif