6 H. MOHN. METEOROLOGY. [norw. pol. exp. 



Ranged according to temperature 



at 9 ° Corr. f. Adie 763 = + 0-102 mm. 

 ■ 13 — - — „ + 0-086 „ 



Higher temperatures give lower corrections, quite in accordance with the 

 result found in 1893 in Christian ia. 



Ranged according to quarter years 



1893 October — December. 



1894 January— March. 

 „ April — June. 

 „ July — September. 

 „ October — December. 



The weighted mean becomes 



at 11-2° Corr. = + 0-094 mm. 

 without any appreciable variation with time. 



After the return of the Expedition, Adie 763 was compared with the 

 standard barometer of the Meteorological Institute, from November 27th, 1896, 

 to March 31st, 1897. The number of comparisons was 86, and the height 

 of the mercury ranged from 727 mm. to 776 mm. Treated in the same 

 manner as above, the result was as follows: 



Attached Thermometer t Correction 



— 2-6° + 0-38 mm. 



2-2 + 0-30 



18-6 + 0-10 



25-2 + 0-02 



Weighted mean 8-0 + 0-235 mm. 

 and Correction = + 235 — 00127 {t° - 8-0°) = + 0-337 — 0-0127 t mm. 



The corrections found in this manner are practically the same for all 

 heights of the barometer. Taking 4 groups out of the 86 observations, each 

 containing 5 observations, one with low temperature and high pressure, one 

 with low temperature and low pressure, one with high temperature and high 

 pressure, and one with high temperature and low pressure, I obtain the 

 following means for each group (6, barom. observed): 



