14 No. 99 GEOGRAPHY To the south of the Equator somewhat similar con ditions prevail. The mean annual temperature tends to increase southward and varies from 75 ° to 78 ° F.

(24 ° to 25.5° C.). The annual range also increases and in places is as much as 9 ° F. (5 ° C. ) . Over this part of the central basin March is generally the hottest month.

In the Katanga, which is farther removed from the Equator and is at the same time much higher, the cli matic regime is more varied. At Elisabethville the mean annual temperature is 68 ° F. (20 ° C. ) , while the range between October, the warmest month, and July, the coldest, is about 16° F. (9 ° C. ) . This region and perhaps some districts of the Eastern Highlands for which figures are not available appear to be the only parts of the Congo suitable for European settlement.

The greater part of the Congo falls within the belt of equatorial rains which moves backward and forward with the apparent motion of the sun. The region of heaviest rainfall is at or near the Equator, where there is a mean annual precipitation of 65 to 70 inches (1,650 to 1,780 mm. ) . In this region rain falls at all seasons, and although it is fairly well distributed throughout the year, there is a double maximum-one in April or May and the other in October and November.

Over the whole of the region north of the Equator the conditions are somewhat similar. As a rule the double maximum is well marked , but there is no distinctly dry season . In the district north of the Welle, however, there is very little rainfall in December and January, when the sun is well to the south. Taking the region as a whole the mean annual precipitation tends to fall between 60 and 65 inches ( 1,520 and 1,650 mm . ) , except in the Eastern Highlands, where it is less .

South of the Equator the rainfall is on the whole lower. In the central basin it is generally over 55 inches ( 1,400 mm. ) , but it decreases to the east, south -east,