204 A. N. Pearson — Variations of Rainfall in Northern, &c. [No. 3, 



fact can be expressed numerically by taking the percentage rainfall as 

 given in the " Difference " columns of the above table ; when it will be 

 seen that the winter rainfall of the 2nd year was 16-3 heavier than during 

 the 1st and 3rd years taken together ; while the summer rainfall was 

 14-6 heavier. The numbers^ 16-3 and 14-6, which according to this me- 

 thod are a measure of the excess of the winter and the summer rainfall 

 respectively during the 2nd year, approach each other sufficiently to be 

 noticeable. 



The nature of the quantitative relation during the negative years, 

 namely, the 7th, 8th, and 9tli, will be best seen by an examination of the 

 actual rainfall of those years. This, obtained from Mr. Hill's Tables 1 (A 

 and B) and 111 (A and B), is as follows : — 



Year of the 



Winter Bainf all. 



Summer Rainfall. 



Cycle. 



Hills. 



Plains. 



Mean. 



Hills. 



Plains. 



Mean. 



1st 

 2nd 

 3rd 



inches. 



17-95 



9-58 

 16-55 



inches. 



6-30 

 3-23 

 4-59 



inches. 



12-12 



6-40 

 10-57 



inches. 



41-81 

 54-01 

 47-13 



inches. 



26-.36 

 34-63 

 27-03 



inches. 



34-08 

 44-32 

 37-08 



Average of 



the three 



years. 



, 



9-70 







38-49 



Dealing only with the mean results, the variations in each year 

 from the three years' average are in the case of the summer and the 

 winter rainfalls respectively as follows : — 





7tli year. 



Sth year. 



9th year 



Winter 



+ 2-42 



— 3-30 



+ 0-87 



Summer 



— 4-41 



+ 5-83 



— 1-41 



Now the point to be noticed is that 



2-42 : 4-41 : : 3-30 : 5-83 



0-87 : 1-41, 



or very nearly so ; the winter figures to be in exact proportion should be 

 2*53, 3-34, and 0-81 ; but the approach to exactness is sufficiently near 

 to be striking, and to make one suspect that there has been something 

 more than chance at work in its production. If this proportion can be 

 established as a general rule, it will signify that, during the three years 



