518 



H. MOHN. METEOROLOGY. 



[NORW. POL. EXP. 



THE ANNUAL PERIOD. 



The following Table gives the mean amount of cloud for each month 

 during the drift of the Fram, extracted from the Table on pp. 511, 512. 



Annual Mean 6'23 



Minimum 3'59 December 28 th 

 Maximum 8'84 July 27 th 



Range 5*25 



From October to April, the amount of cloud is below the mean for the 

 year, from May to September it is above. The winter months are remark- 

 ably clear, the summer months very cloudy. PI. VIII. (1 cm. = 2 of cloud-scale). 



The average number of clear days and of overcast days are 



PI. VIII. 1 mm. = 1 day. 



