374 ACCOUNT OF THE AllCTIC REGIONS. 



suits *. Ill the month of JMay, during 12 years, 

 the mean maximum pressure, being the mean of 

 the highest observation each year, is 30.36, the 

 mean minimum 'pressure 29-43, and the mean 

 of the two 29.89, corresponding with the mean 

 pressure to within two hundredth parts of an inch. 

 And from the observations during ten years in 

 June, a simihir result is obtained : Mean maxi- 

 mum 30.25, mean minimum 29.47, mean of the 

 two 29.86, and mean pressure 29.869 ; difference 

 only 0.009. But the comparison of the greatest 

 with the least pressure that occurretl during the se- 

 ries of years, is scarcely less striking : Highest 

 observation in June 30.37, lowest 29.25, and mean 

 29.81 ; differing from the mean pressure 0.059. 

 And highest observation in May 30.57, lowest 

 29.23, mean 29.90 ; differing from the mean pres- 

 sure, by above 1000 observations, only 0.009- 



The following are the relations which, in polar 

 latitudes, I have been enabled to trace between the 

 barometer and the weather. 



1. A hard westerly gale with snow, occasions the 

 greatest depression of the mercury, and a light east- 

 erly wind with dry weather, the greatest elevation. 



2. The rising of the mercury foretels the sub- 

 sidence of wind or rain, a change of wind, or fine 



" Appendix, No 11. Table A. 



