490 



H. MOHN. METEOROLOGY. 



[NORW. POL. EXP. 



to 19 - 0, and the registered temperature from 43'0 to 5'4, a total rise 

 of 37' 6. The wind was southerly and the barometer falling from 767 mm. 

 on the 20 th to 724 mm. the lowest reading observed during the whole 

 expedition on the 22 nd . In summer the variation does not exceed 5, that 

 in July not going above 2. The column 1 shows a very regular annual 

 period with a decided maximum in July. The summer is the quiet time as 

 regards the temperature of the air. 



The following Table shows, for each month, the mean number of cases 

 in which the mean daily temperature was rising (-(-) or falling ( ) continu- 

 ally during 1, 2, 3, 4, 5 or 6 days, or the frequency of temperature-periods of 

 different lengths. When a period comprises the end of one month and the 

 beginning of the next, it has been reckoned to the former month. 



The Table also gives the mean duration of a temperature-period in days, 

 separately for rising (-}-) and falling f ) temperature. 



