344 GENERAL OBSERVATIONS. 
of the river in July and August militating against such an 
hypothesis, it has the contrary tendency of giving additional 
weight to it, “ provided” he goes on to say, * the river should 
begin to swell in the early part of September, an event I 
am taught to expect, and for which Lam anxiously looking 
out.” ‘The river did begin to swell at the precise period 
he had anticipated ; and that circumstance corroborating 
the previous conclusion he had drawn, induces him to note 
down in his journal, that « the hypothesis is confirmed.” 
Tt is evident that Captain Tuckey, on the latter part of 
his journey, could only put down a few brief notes to re- 
fresh his memory, which, from his exhausted state, on his 
return to the vessels, he was wholly unable to enlarge or 
explain ; and thus the reasoning on which he had built his 
hypothesis is lost to the world: he lamented, it seems, when 
on his death-bed, that he could not be permitted to live 
to put in order the remarks he had collected in tracing 
upwards this extraordinary river. Unfortunately none 
of the party has escaped to supply this deficiency ; the 
solidity, however, of Captain Tuckey’s conclusion is not 
shaken, but rather corrobated, by what is known of physi- 
cal facts and the geographical probabilities, as connected 
with northern Africa. These may be briefly stated. 
In‘the tropical regions, the rains generally follow the 
sun’s course, and are not at their height till he approaches 
the tropics ; hence arises the exhausted state of the lakes of 
Wangara in the months of May, June, and July, and their 
overflowing in the middle and latter end of August, ac- 
cording to the observations of the Arabian geographers ; 
