PROCEEDINGS 



ROYAL SOCIETY OF EDINBURGH. 



VOL. II, 



1846-7. No. 29. 



Sixty-Third Session. 

 First Ordinary Meeting^ 7th December 1846. 



Sir THOMAS MAKDOUGALL BRISBANE, Bart., Presi- 

 dent, in the Chair. 



The following Communications were read : — 



1. On the Mean Height of the Barometer in different Lati- 

 tudes. By Professor Hansteen of Christiania. Com- 

 municated in a letter to the Secretary. 



Professor Hansteen first shews, that the remarkable difference of 

 1'62 French lines, by which the barometer reduced to the level of 

 the sea, is higher at Paris than at Christiania, cannot be ascribed 

 solely to the effect of the difference of gravity of the mercury in the 

 barometer at the two places. The author then gives an empirical 

 formula to represent the mean height of the barometer in any lati- 

 tude which he compares with observations. This formula is the fol- 

 lowing — 



>^=r 336-810 -f- 1-304 cos. 2p--748 cos. 4^-0-914 cos. 6<p 

 + 0-543 COS. 8 ip. 



Where vj/ is the oscillation in French lines, and p the latitude. 



It gives a minimum for ^ = 0, and p = 68*^ 24'. 

 And maximum for p = 36^ 13', and f = 90. 

 VOL. II. K 



