22 Transactions of the Sotith African Philosophical Society. 



as indicated above, is that the annual rain wave, becoming later and 

 weaker as it journeys inland from the east coast, meets the south 

 coast somewhere between Mossel Bay and Cape L'Agulhas in April,, 

 and reinforces the strongly marked semi-annual rain wave of the 

 South Coast there, being scarcely felt at all further east. 



It being fairly clear that the rains of Kimberley and Durban are 

 included in the same system of summer rains, the extent of the 

 relationship becomes an interesting question. Daily observations, 

 are published for the latter place, and therefore individual rains as 

 well as monthly totals may be considered. Now it happens that 

 there is not any real resemblance in the character of the showers of 

 the two places. At Kimberley the heavier rain comes with a 

 barometric depression ; at Durban with a barometric crest. At 

 Kimberley, speaking at large, the barometer rises as the heavy rain 

 ceases ; if there be more rain it is generally in small clearing, 

 showers. At Durban the barometer falls when the rain comes to> 

 an end. There were at Kimberley, in the five years 1897-1901, 

 72 heavy rains sufficiently isolated from other rain to admit of direct 

 comparison with the pressures ; at Durban there were 100 during 

 the same period. By tabulating the barometric pressures of the 

 days upon which the rain ended, for either place, together with three 

 days before and two days after, we get the following comparative 

 series of averages : — 



Durban. Kimberley. 



Third day before 30-075 inches 26-139 inches 



Second „ 30-061 26-131 



First „ 30-135 26-102 



EAIN DAY 30-252 26-090 



First day after - 30-158 26-130 



Second „ 30-125 26-137 



This is a result of considerable importance. 



From a comparison of the monthly averages of Kimberley and 

 Durban I have tried to determine whether a wet or a dry month at 

 one place signifies a like or unlike state of things at the other. In 

 Table 27 this has been done by tabulating in four columns : — 



1. When the fall at both places is less than the mean. 



2. When the fall at both places is greater than the mean. 



3. When the fall at Durban is greater than the mean, but at 



Kimberley less. 



4. When the fall at Durban is less than the mean, but at Kim- 



berley greater. 

 The Table includes the twenty-six years 1877-1902— i.e., 312 



