202 Proceedings of the Royal Physical Society. 
belt of calms at the equator. These winds naturally dis- 
tribute the rainfall, but the distribution is unequal, for we 
can find regions in Africa where there are under 4 inches of 
rainfall, and others where there are over 100. Speaking 
generally, however, it will be seen that in Central Africa the 
annual rainfall may be estimated at from 50 to 60 inches. 
The rainfall at the equator is pretty evenly distributed 
throughout the whole year, but north of the equator, at about 
15°, there are two well-marked wet seasons. 
The heat, rainfall, and winds affect the fertility of the 
country, and the whole region may be divided as follows :— 
36-4 per cent. is occupied by deserts, 14°6 by steppes, 5:3 by 
scrub, 21°3 by savannahs, 21°8 by forests and cultivated land, 
and 6 per cent. by the larger lakes. 
It follows that half the continent is occupied by deserts 
and steppes, while less than a quarter consists of fairly fertile 
lands, of which a large portion is covered with forest. The 
typical zones of vegetation in Africa are—firstly, the Medi- 
terranean zone, having a vegetation similar to that of Southern 
Europe, if somewhat more tropical; secondly, the Sahara 
desert zone, of which much might be cultivated, and where 
undoubtedly numerous oases exist; thirdly, the zone of 
tropical vegetation, more or less coincident with the highest 
mean annual temperature and heaviest rainfall; and lastly, the 
south central and South African savannah zone. Practically 
speaking, we may say that vegetation is richer as we proceed 
from south to north, and also from west to east. The mam- 
malian fauna of Africa are exceptional, but I have only time 
to mention the hippopotamus and giraffe, the elephant, various 
species of antelope, the buffalo, zebra, and wild ass ; beasts 
of prey—the lon, leopard, panther, hyena; numerous apes, 
chimpanzees, and gorillas. The bird fauna of Africa are not 
rich, but the reptile fauna are largely developed. Vipers of 
the most deadly kind, such as the puff-adder, are encountered, 
while crocodiles abound in all the larger rivers. Insect life 
is very abundant; locusts form a plague in some parts; and 
the tzetse fly, the bite of which is fatal to horses, oxen, sheep, 
and dogs, infests large parts of the country which are un- 
cleared. 
