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an extra inch for each 30 miles ; between Kimberley and Durban the increase 
is 1 in. for each 17 miles. 
XVII. Bechuanaland. 
A remarkable feature here is the exceptionally high rainfall of Maf eking. 
No very obvious explanation of this circumstance is forthcoming ; but the 
rainfall over the greater part of this area is very variable from year to year, 
floods alternating with long droughts, and Mafeking may have got more 
than its share of the former. The run of the averages for Palapye Road 
and Serowe (XYII, 318, 319) is interesting, and not the less so because no 
particulars of the rainfall of Chief Khama's headquarters have hitherto been 
published. Another interesting and new station is Tsau, on the northern 
border of Lake Ngami. Though the record here summarised is a short one, 
it suggests that some previous assumptions regarding the rainfall round 
about the Lake were quite wrong. 
XVIII. Damaraland ami Great Namaqiialancl. 
In this interesting region we have desert conditions on the coast belt, 
with a gradual improvement from west to east and from south to north. To 
the north-east the general rain conditions are at least as good as those of 
Grriqualand West (compare XVIII and III with IX). A remarkable 
feature is the rapidity with which the type changes from a winter to a 
summer rainfall in the vicinity of the Orange River. 
XIX-XXIII. Transvaal. 
This area is not strictly comparable with the others. The mean January, 
February and March rainfalls for nearly all the stations are artificial, 
January counting from 1-30, March from 2-31, and February from January 
31 to March 1. Few of the stations have much of a record, the exceptions 
being the mining areas. The fall increases from west to east on the whole. 
It is high in the north-east highlands, but falls off over the lower levels 
adjacent to the Portuguese border and Rhodesia. It is mostly thunderstorm 
rain, with a summer maximum and minimum. 
XXIV and XXV. Sotithern Bhodesia. 
This area also shows the increase of rain from west to east. It shows 
also on the whole a heavier summer and a lighter winter rainfall than the 
Transvaal and Bechuanaland do. 
XXVI. Portuguese East Af rica. 
Most of these stations are on the coast. The rainfall varies very much 
from one year to another, so that the short records cannot possibly give very 
good averages. Thus while five years of published observations at Beira 
gave a mean annual rainfall of nearly 51 in., the inclusion of a further 
