476 



Royal Society :• 



duced by Mr. Symons from ten stations (British Association 

 Beport, 1865, p. 203; 1871, p. 102). The differences of spot-area 

 from the mean, in millionths of the sun's surface, and of the rain- 

 fall for each year are given in the following Table : — 



Differences of Rainfall for Great Britain and of Sun-spot 

 area for 1832 to 1867. 





















Means. 



Year. 



AA. 



AR 



Year. 



AA. 



AR 



Year. 



AA. 



AR 



























AA. 



AR. 







in. 







in. 







in. 





in. 



1832. 



-359 



-1-54 



1843. 



-540 



+2-66* 



1854. 



-501 



-5-36 



-467 



-1-41 



1833. 



-558 



+ 1-97* 



1844. 



-465 



-4-02 



1855. 



-566 



-4-47 



-540 



-2-17 



1834. 



-506 



-3-22 



1845. 



-232 



+0-13* 



1856. 



-619 



-1-85 



-452 



-1-64 



1835. 



+171 



+0-82 



1846. 



- 5 



+1-83* 



1857. 



-428 



-2-04 



- 87 



+020 



1836. 



+746 



+5-75 



1847. 



+469 



-1-94* 



1858. 



+ 177 



-4-95* 



+444 



-0-38 



1837. 



+556 



-3-20* 



1848. 



+395 



+8-24 



1859. 



+756 



+0-79 



+569 



+1-94 



1838. 



+293 



-0-63* 



1849. 



+203 



+0-77 



1860. 



+656 



+5-60 



+384 



+1-91 



1839. 



+ 164 



+3-53 



1850. 



-123 



-1-39 



1861. 



+659 



-0-76* 



+267 



+0-46 



1840. 



- 46 



-3-07 



1851. 



+ 40 



-1-04* 



1862. 



+530 



+2-63 



+174 



-049 



1841. 



-306 



+5-77* 



1852. 



- 92 



+7-79* 



1863. 



- 15 



-0-81 



-138 



+4-26 



18413. 



-429 



-2-21 



1853. 



-253 



-0-36 



1864. 

 1865. 

 1866. 

 1867. 



+245 

 -187 

 -342 

 -468 



-563* 

 +1-90* 

 +3-26* 

 +0-70* 



-146 

 -409 

 -458 

 -440 



-2-73 

 -0-27 

 -1-74 

 -0-34 



If we seek the value of / for the mean of the three periods of 

 eleven years commencing 1832 and 1835, we find the following 

 equations : — 



1832 to 1864 AE= + 0-0019 AA ; 



1835 to 1867 AK= +0-0011 AA. 



These results, then, are, as we expected, in conformity with 

 Mr. Meldrum's conclusion; so that if we compare the year of 

 largest with that of smallest spot-area, the difference of rainfall 

 should amount to 2-61 in. by the first and to 1*51 in. by the 

 second value of /. If we take the mean spot-area for the years 

 1834, 1844, 1856, and 1866, and for 1836, 1848, and 1861, we 

 find that the mean difference of rainfall for these years should 

 be 2-06 in. by the first and 1*20 in. by the second value of /, in- 

 stead of 8 k 45 in. as found by Mr. Meldrum. 



It will be seen also that the greatest mean difference of rainfall 

 is that for the years 1841, 1852, and 1863, and this was an excess 

 of rain for years of spot-area deficiency ; were another such 

 opposite difference to present itself, it would neutralize the con- 

 clusion derived from these means. It should also be observed 

 that while the first and third periods of eleven years are in favour 

 of the connexion, the second (1843 to 1853) is opposed to it (this 

 is also the case for the eleven years 1857 to 1867). 



It will be seen, then, that from this discussion a probable 



* Indicates opposite signs of AA and AR. 



