122 

 PHYSICAL AND MATHEMATICAL SECTION. 



November 7tli, 1871. 



Alfred Brothers, F.RA.S., Vice-President of the Section, 



in the Chair. 



" On Changes in the Distribution of Barometric Pressure, 

 Temperature, and Eainfall under different Winds, during a 

 Sohir Spot Period," by Joseph Baxendell, F.R.A.S. 



[This paper was afterwards read at the Ordinary Meeting 

 of the Society held March 5, 1872. See p. 111]. 



December 5th, 1871. 

 Thomas Carrick, Esq., in the Chair. 



" On the Distribution of Rainfall under different Winds, 

 at St. Petersburg, during a Solar Spot Period," by Joseph 

 Baxendell, F.R.A.S. 



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, 



