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 saj^ " die 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 draAvn, induces him to note 

 down in his journal, that " the hypothesis is confirmed." 



It 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, wiiich, from his exhausted state, on his 

 return to the vessels, he Avas wholly unable to enlarge or 

 explain ; and thus the reasoning on which he had built his 

 hypotiiesis 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 

 Avith 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 ; 



