146 MR. J. BAXENDELL ON THE ST. -PETERSBURG 



tinuous daily, or even hourly, record may be obtained of 

 the state of the solar disk and its appendages, and the 

 results discussed in connexion with those of observations 

 of meteorological phenomena. 



XVII. On the Distribution of Rainfall under different 

 Winds, at St. Petersburg, during a Solar-spot Period. 

 By Joseph Baxendell, F.R.A.S. 



Read before the Physical and Mathematical Section, December 5, 1871. 



In the paper which I read at the last meeting of the 

 Section it was shown that, at Oxford, changes take place 

 in the relative amounts of rainfall under different winds in 

 a period corresponding with that of solar- spot frequency. 

 Thus, in the years when the number of groups of solar 

 spots, as observed by Schwabe, was above the average, the 

 amount of rainfall under west and south-west winds was 

 greater than that under south and south-east winds, while 

 in the years when the number of groups of solar spots was 

 below the average the reverse of this took place, the amount 

 of rainfall under west and south-west winds being less than 

 that under south and south-east winds. The hypothesis 

 which led to the investigation requires, however, that great 

 diversity should exist in the relative amounts of rainfall 

 under different winds at different stations. While at some 

 the distribution will be similar to that at Oxford, at others 

 it will be of an opposite, and in others again of an inter- 

 mediate character; but, whatever may be the nature of 

 the distribution at any station, the changes to which it will 

 be subject will take place in a period identical with the 

 solar-spot period. In some localities the changes will be 

 so slight, or so irregular, as not to be immediately referable 



