of Edinburgh, Session 1869 - 70 . 139 
Arangoa river in February, and they ended with him on the 
eastern side of the Nyassa in June. 
On the Zambezi river in the Makololo district, Livingstone 
observes that the rain follows the course of the sun, since it falls 
first in October and November when the sun goes over this zone 
southward. When the tropic of Capricorn is under the sun in 
December, it is dry, and December and January are the months in 
which the droughts are most severe in the countries between the 
Zambezi and the Kalahari. When the sun turns again to north¬ 
ward in February, March, and April, the great rains of this part 
of the Zambezi valley are experienced. 
6. Population. 
* 
The Lake Regions of Africa are well peopled. Behm, in his 
“ Geographical Year-book,” has estimated the population of that 
part of Eastern Africa, which lies between the equator, the line of 
Lake Tanganyika, the Cazembe’s country, and the Portuguese 
colonies on the coast, at 3,500,000. This gives a density of popu¬ 
lation of about six to a square mile, but is apparently rather under 
than above the mark. It is true that the slave trade must reduce 
and disturb the population of this part of Africa to a great extent, 
since many thousands of slaves are annually brought down to and 
exported from the harbours on the coast; but, on the other hand, 
travellers in this region report a continuous population. Captain 
Grant describes the part of the Lake Region which he traversed as 
too thickly peopled to harbour many wild animals; the shores of 
Lake Tanganyika are, according to Speke, “ thickly inhabited by 
numerous tribes and in his voyage on Lake Nyassa, Livingstone 
says, “ Never before in Africa have we seen anything like the dense 
population of the shores of Lake Nyassa, especially in the south. 
In some parts there seemed to be an unbroken chain of villages. 
On the beach of well-nigh every little sandy bay, black crowds 
were standing gazing at the novel spectacle of a boat under sail.” 
The inhabitants of the Lake Region appear to belong entirely to 
the negro or negroid race, but are closed in to north and south by 
peoples of a different stamp. 
The Niam Niams who inhabit the country north of the lake 
reported by Piaggia, and west of the Albert Lake, who had formerly 
