1881. ] Geography and Travels. 345 
have observed that the waters are gradually retiring, and this at 
a very regular rate, except during the rains (when, however, there 
is no rise). Three months ago the Arabs agreed in telling me, 
‘Now.the lake is the same as when Cameron was here.’ The 
partly submerged palm-tree on which I had fixed a water-gauge, 
was then just left dry, and the Arabs told me that Cameron used 
this tree as a target and that it was then just at the water’s edge. 
Now, all the observations and the reports I hear lead me to believe 
that the jake has been gradually rising for years, and that it rose 
until it burst open the Lukuga obstruction, first oozing throug 
in small quantities as when seen by Cameron. at the waters 
should now rush through the Lukuga instead of gently overflow- 
ing is probably due to the first burst having eroded a deeper 
channel; for, according to the geological nature of the Lukuga 
gap, so will the waters cut a deeper and deeper chasm, or eventu- 
ally find a permanent level and gently flow over a rocky sill. I 
this periodical rising must have been infinitesimal, if any, com- 
pared with that of the few years immediately preceding the burst- 
ing of the Lukuga, or we must do away with the ancient charac- 
ter of the lake. Iam convinced that the lake never (or, at any 
rate, for very many years), was at such a height as it was two years 
ago. This is quite apart from any geological evidence of a dif- 
ferent state of ‘things in remote ages. And I cannot believe that 
the lake has always been rising at this rate. Now, how is it that 
this enormous quantity of water could rise so quickly in spite of 
that evaporation which has (as is supposed) been sufficient for 
ages to maintain it almost at a level. A succession of extraordi- 
nary rainy seasons, of which we have -no evidence, would not 
account for it. I can bear testimony to an enormous evaporation, 
but how is it that the waters suddenly gained upon the evapora- 
> 
\. and S. was observed at twelve different places, and the coast 
line between them laid down by compass bearings. 
VOL. XV.—NO, WV. 24 
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