232 



REPORT — 1878. 



12. It will be seen that the " mean cycle " exhibits a well-marked sun- 

 spot variation. Now if the sunspots are numerically related to the rain- 

 fall, an exactly similar treatment of the rainfall should give a rainfall 

 variation, corresponding, either directly or inversely, with the sunspot 

 variation. 



13. In the next table the sunspot numbers for the minimum years' 

 1823, 1833, 1843, 1856, and 1867, are all in the eighth line, and the 

 places and numbers for the maximum years are marked with astei'isks. 



Table II. — Sunspot numbers. — Minimum years in 8th line. 



The table has been formed in the way in which Table I. has been 

 formed. 



All the maximum years except 1829 contribute to the formation of 

 the first and eleventh terms of the mean cycle. 



The mean of the mean cycle is 49"8, and the mean for the whole 

 period (1816-72) is 51-3. 



As in Table I., the mean cycle exhibits a well-marked variation, the 

 sunspots decreasing to the seventh year, and then increasing to the 

 eleventh. 



If, then, the sunspots and the rainfall are numerically related, a 

 corresponding variation should be found for the rainfall, when similarly 

 treated. 



II. — Rainfall of Great Britain compared with the Sunspots. 



14. The rainfall of Great Britain, as represented by returns from 

 fifty-four stations in different parts of the country, is given in Table III. 



The following table has been prepared in the same way as Table I. 

 (Sunspots), and it will be seen from the last two columns but one that 

 the rainfall and sunspot variations are remarkably similar, the rainfall 

 increasing from the first to the sixth year of the cycle, and then de- 

 creasing to the eleventh. 



The same stations have been used in finding the annual mean rainfalls 

 for each series of thirteen years. 



The mean of the mean cycle is 31 '4 inches, and the mean rainfall 

 from 1824 to 1867 is 312 inches. 



