Some Besults from the Periodic FormulcB. 115 



Kimberley falls about the 1st of July, and the minimum, therefore, 

 about the 1st of January ; at Umtata it is some six or seven days, 

 and at Durban twelve days later. The sequence, then, is the same 

 as that of temperature, but with a shorter interval of time : for 

 while the maximum temperature phase at Kimberley comes five 

 days earlier than the minimum pressure phase, at Durban the 

 pressure phase precedes that of the maximum temperature by nearly 

 eighteen days. The inference seems to be that many of the pheno- 

 mena of pressure at Durban are the outcome of a chain of operations 

 originating on the Table-land above. 



The term of six-months period decreases its amplitude with 

 altitude ; the phase-time at Kimberley precedes that of Umtata by 

 nearly 40 degrees of arc, and that of Durban by more than 

 87 degrees, corresponding to time intervals of about twenty and 

 forty-four days. The phase-times of highest mean pressure are 

 roughly — 



Kimberley Dec. 15th and June loth 



Umtata Jan. 5th and July 5th 



Durban Jan. 30th and July 30th 



The amplitude of the term of four- months period is larger at 

 Kimberley than at Durban, and still larger than it is at Umtata. 

 'The phase-times of highest mean pressure are about — 



Kimberley 13th Mar., July, and Nov. 



Umtata 3rd Mar., July, and Nov. 



Durban 2nd Mar., July, and Nov. 



The amplitude of the term of three-months period is remarkably 

 small at Umtata, therein being in marked contrast to the collateral 

 maximum temperature term. The phase-times of highest mean 

 pressure are about — 



Kimberley 27"' th Mar., June, Sept., Dec. 



Umtata 16th Mar., June, Sept., Dec. 



Durban 8th Jan., Apr., July, Oct. 



The temperatures prove to be of exceptional interest. Upon 

 referring to the Tables it will be seen that so far as the mean 

 temperature is concerned the amplitude of the annual term increases 

 with fair regularity from the coast to the interior, and also that the 

 phase-time comes earher in the same direction, ranging from a time 

 interval of ten days at Umtata to twenty-one days at Kimberley. 

 The phase-times of the term of six-months period are in the reverse 



