98 MR. J. BAXENDELL ON TEMPERATURE, ETC. 



It is remarkable that the epoch of maximum indicated 

 by the Geneva and Great St. Bernard observations cor- 

 responds exactly with the epoch of minimum magnetic 

 disturbance, as determined by General Sabine from the 

 observations made at the Colonial observatories and at 

 Pekin; and it is probable that there is also a close cor- 

 respondence between the periods of the two phenomena. 



Mr. Vernon, in his paper " On the Irregular Barometric 



Observations at Geneva and the Great St. Bernard/^ has 



given the mean monthly temperatures at these two stations, 



derived from observations made during the twenty years 



183 6- 1855; and Prof. Plantamour, in a paper in the 



13th volume of the ^Memoirs of the Physical and Natural 



History Society of Geneva,^ has given the mean annual 



temperatures from observations during the ten years 



1841-1850. From these data, and those given above, I 



find that — 



V The average difference of temperature o 



of the two stations for the five years 183 6-40 = 1 9*046 



„ „ seven years i84i-47 = i9'697 



„ ,, three years 1848-50=1 9*206 



„ „ seven years i85i-57=i9*89o 



These results, taken in connexion with the course of the 

 curve laid down from the numbers derived from the com- 

 parison of Geneva and Milan with the Great St. Bernard, 

 indicate a period of about ten years, which, according to 

 General Sabine, is also the period of magnetic disturbance. 



I cannot conclude without expressing my grateful ac- 

 knowledgments to my friend Mr. Vernon, F.R.A.S., for the 

 valuable assistance he has rendered me in procuring data, 

 and in referring to original publications for the purpose 

 of clearing up doubtful points ; and I may add that, with- 

 out the means of reference afforded by the many valuable 

 volumes of meteorological observations now in the So- 

 ciety's Library, it would have been quite impossible to 

 have undertaken an inquiry of this nature. 



