affected by disturbing causes than those coming from the 

 eastward over the continent of Europe, it appeared to me 

 that the nature of the law of change of the pressures would 

 be best indicated by a comparison of the differences between 

 the pressures under north-west and south-west winds. 

 These differences are as follows : — 



These numbers indicate a maximum at the end of 1859, a 

 minimum in the latter half of 1866, and a secondary maxi- 

 mum at the end of 1863, thus presenting a very close agree- 

 ment with the results obtained by De la Rue, Stewart, and 

 Loewy from actual measurements of the areas of the sun 

 spots observed during the period under discussion. 



The mean pressure under all winds is 29*744 inches in 

 both periods, but the sum of the differences of the indivi- 

 dual pressures from this mean is 0-75 oin. in the first period, 

 and only 0-530in. in the second. It appears therefore that 

 the forces which produce the movements of the atmosphere 

 are more energetic in years of maximum solar activity than 

 in years of minimum. 



Teinjperatwre. 



In the first period the maximum temperature occurs 

 under winds from south-west, and in the second period 

 under winds from about south-south-east. The greatest 



