76 APPENDIX. [sect. 



dews also, night and morning, such as are not seen in the 

 south. The rains are warm on the Zambesi, farther east. 

 Showers have been seen, and thunder heard, in South Africa, 

 without clouds. 



The following extract gives an interesting account of the 

 theory of African rains: "The characteristics of the rainy 

 season in this wonderfully humid region (Londa), may account 

 in some measure for the periodical floods of the Zambesi, and 

 perhaps the Nile. The rains seem to follow the course of the 

 sun, for they fall in October and November, when the sun 

 passes over this zone on his way south. On reaching the 

 tropic of Capricorn in December, it is dry; and December and 

 January are the months in which injurious droughts are most 

 dreaded near that tropic (from Kolobeng to Linyanti). As he 

 returns again to the north, in February, March, and April, 

 we have the great rains of the year; and the plains, which in 

 October and November were well moistened, and imbibed 

 rain like sponges, now become supersaturated, and pour forth 

 those floods of clear water which inundate the banks of the 

 Zambesi. Somewhat the same phenomenon probably causes 

 the periodical inundations of the Nile. The two rivers rise in 

 the same region; but there is a difference in the period of 

 flood, possibly from their being on opposite sides of the 

 equator. The waters of the Nile are said to become turbid in 

 June; and the flood attains its greatest height in August, or 

 the period when we may suppose the supersaturation to occur. 

 The subject is worthy the investigation of those who may 

 examine the region between the equator and 10° south; for 

 the Nile does not shew much increase when the sun is at its 

 furthest point north, or tropic of Cancer, but at the time of its 

 returning to the equator, exactly as in the other case when he 



is on Capricorn, and the Zambesi is affected The above 



is from my own observations, together with information derived 

 from the Portuguese in the interior of Angola; and I may add 

 that the result of many years' observation by Messrs Gabriel 



