254 General Strachey on the Correspondence of [May 31^ 



but an objection may possibly be made to the effect that the sun-spot 

 period is not exactly a cycle of eleven years, and that a better result may 

 be obtained by a comparison of the observations corresponding to the 

 known periods of maximum and minimum sun-spots, without reference 

 to any special length of cycle. The following Tables show the results 

 thus arrived at, the figures representing differences from the mean rain- 

 fall for the whole sixty-four years. 



Table IV. 



Rainfall near periods of maximum sun-spots. 



Rainfall near periods of 



minimum sun- 



3pots. 



Years. 



Two 

 years 

 before. 



One 

 year 

 before. 



Maxi- 

 mum. 



One 

 year 

 after. 



Two 

 years 

 after. 



Years. 



Two 

 years 

 before. 



One 

 year 

 before. 



Mini- 

 mum. 



One 

 year 

 after. 



± WO 



years 

 after. 



1817. 



in. 

 + 7-5 



in. 

 - 7-4 



in. 

 + 151 



in. 

 +27-7 



in. 

 -12-2 



1823. 



in. 

 - 1-4 



in. 

 4-11-1 



in. 

 -21-9 



in. 

 -14-8 



in. 

 + 7-5 



1830. 



-106 



-11-6 



-16-1 



- 4-2 



-30-1 



1833. 



- 4-2 



-301 



-11-4 



- 9-5 



- 7-0 



1837. 



- 70 



- 3-8 



- 0-8 



4- 3-8 



+ 4-6 



1843. 



+ 9-8 



-12-0 



4 1-8 



+ 16-9 



-10-5 



1849. 



+32-5 



4- 6-3 



- 8-7 



— 11*6 



4-15-8 



1856. 



- 5-3 



-16-2 



- 1-5 



+ 4-4 



- 00 



1860. 



- 0-0 



4- 6-6 



-20-9 



-11-3 



-10-3 



1867. 



- 6-9 



+ 2-9 



-241 



- 7-1 



-16-2 



1871. 



-16-2 



+25-6 



4- 7-8 



4-25-2 



+ 3-3 















Mean... 



4- 1-0 



+ 2-6 



- 4-0 



4- 4-9 



- 4-8 



Mean... 



- 1-6 



- 8-9 



-11-4 



- 2-0 



- 5-2 



Mean 

 difference 

 from mean 



1 12-6 



• 



10-2 



10-0 



143 



12-7 



Mean 

 difference 

 from mean 



[ 4-6 



12-7 



9-3 



101 



7-2 



Mean of mean differences 12-0 inches. 



Mean of mean differences 8- 



8 inches. 



These results are also negative. The maximum period cannot be said 

 to be indicated at all. The minimum shows a diminished mean cyclical 

 deviation, but this is due to the years furthest from the supposed mini- 

 mum epoch ; and if the three central years alone are reckoned, the result 

 is much the same as obtained from the 11-year cycles. 



I have sought for a further test of the character of the conclusions 

 that I have been discussing in the rainfall observations at Bombay and 

 Calcutta, which have been made for the greater part of the period over 

 which those at Madras extend. It is hardly conceivable that there should 

 be a coincidence with the sun-spot period, such as is supposed to have 

 been found at Madras, based on any physical cause, which should not in 

 some way be discernible in the rainfall at Bombay and Calcutta. Adopt- 

 ing the same 11-year cycle for the observations at these two places as 

 was used in the case of Madras, the mean results for the three localities 

 are exhibited in the following Table : — 



