RAINFALL DURING A SOLAR-SPOT PERIOD. 



147 



to any well-defined law. These points on the surface of the 

 earth may be regarded as nodal points in the general system 

 of circulation of the great currents of the atmosphere. 



Among the places at which it seemed to me likely that 

 the law of change in the relative amounts of rainfall under 

 different winds would be found to differ considerably from 

 that which prevails at Oxford is St. Petersburg. I there- 

 fore extracted from the volumes of the ' Annales de POb- 

 servatoire Physique Central de Russie' the amounts of 

 rain which fell under different winds at St. Petersburg 

 during the eleven years 1854-64. The results are shown 

 in the following table : — 



Rainfall under different Winds, at St. Petersburg, during a 



Solar-spot Period. 



Year. 



N. 



N.W. 



W. 



s.w. 



S. 



S.E. 



E. 



N.E. 



Calm. 





in. 



in. 



in. 



in. 



in. 



in. 



in. 



in. 



in. 



1854. 



o - 8oo 



0-675 



3'543 



2101 



1-088 



0-776 



1-041 



1-087 



1-644 



1855. 



2*056 



2-688 



1*192 



3*688 



1*720 



o-5S8 



1*509 



0-961 



1-3^5 



1856. 



0-313 



1-014 



5 -I 74 



2-331 



1-386 



1*551 



°*535 



1*852 



0*800 



i857. 



1-871 



o-ooo 



2-700 



1-640 



1-223 



°757 



0181 



2*518 



1856 



1858. 



0*213 



0-445 



2'2l8 



2-441 



°*475 



2-759 



1*025 



1-075 



1-002 



1859. 



o*375 



0-548 



4-961 



4-371 



2*329 



2*251 



1*038 



0-618 



0-639 



i860. 



1-400 



1-182 



2-194 



3-088 



1*910 



2-460 



2*469 



0*301 



0-683 



1861. 



r86i 



0-123 



6327 



2-681 



3-225 



2259 



1*376 



0-978 



C332 



1862. 



1-045 



1-448 



3-290 



2*717 



2*032 



1-921 



o-497 



o-43i 



0-368 



1863. 



0-332 



2-446 



2-521 



3'39° 



3-110 



1-984 



0-512 



0*831 



o-ooo 



1864. 



2-171 



6-560 



3-038 



4*580 



2-017 



7 - 53 2 



I*20I 



2*430 



0-656 



Means 



1-131 



i"557 



3378 



3- 002 



1-865 



2-258 



I,0 35 



1*189 



0*846 



From the mean values in the last line of this table it 

 appears that there was a principal maximum of rainfall 

 under west winds, and a secondary maximum under south- 

 east winds, a principal minimum under east winds, and a 

 secondary minimum under south winds. 



In the eleven years 1854-64 the number of groups of 

 solar spots, as observed by Schwabe and others, was above 

 the average in the five years 1858-62, and below the ave- 

 rage in the remaining six years 1854-57 and 1863-64. 



l2 



