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COMPENDIUM OF GEOGRAPHY AND TRAVEL 
great depth. At various points round the margin hot 
springs of 127° Fahr. bubble up, and warm the western 
end some 10° higher than the temperature of the air. 
It is abundantly stocked with fish and bivalve mollusca, 
but when they approach too near the warmer shore the 
temperature instantly proves fatal to them. 1 This lake 
is widely celebrated throughout the Western Archipelago 
for the tobacco grown upon its shores. The finest quality 
is made only from the topmost leaves, and commands a 
very high price. Two or three other mountain lakes 
occur in the Battak country, but little is known of them, 
and there are probably others in Ache. Of lowland 
lakes and swamps there are many in the neighbourhood 
of the great rivers. 
From the orography of the island it is evident that 
there can be no rivers of any length on the western side 
of the main range of mountains. Upon the other side, 
however, we find the alluvial plain intersected by streams 
of great size and depth, by which the whole interior of 
the country is rendered accessible to commerce. Owing 
to the great rainfall and the steepness of the Barisan 
chain the erosion which takes place is excessive, and the 
rivers bear down enormous quantities of debris which 
deposits around their mouths, blocking the channels and 
adding to the numerous islands and sandbanks by which 
they are beset. The change thus effected in the physical 
condition of the island is enormous. The rapid gaining 
of the east coast upon the Straits of Malacca has already 
been mentioned. It is said that at the time of the 
founding of Palembang the town was situated at the 
mouth of the river, from which it is now distant some 
40 miles as the crow flies. Yet for the most part the 
rivers are not only of great size, but of considerable depth, 
1 A Naturalist's Wanderings in the Eastern Archipelago, H. 0. Forbes. 
