520 



H. MOHN. METEOROLOGY. 



[nORW. POL. EXP. 



In winter and spring the southerly winds have a greater amount of cloud 

 than the northerly winds. In summer the cloudiness is about the same with 

 all winds. In autumn the westerly winds bring the greatest amount of cloud. 

 PL VIII. (1 cm. = overcast). 



Calm weather is attended with clearer sky in the dark season, and a clouded 

 sky in the sunny season. PI. VIII. (1 cm. = overcast). 



FORMS OF CLOUD. 



THE DIURNAL PERIOD. 



The number of cases in which the different forms of cloud have been 

 noted at each alternate hour, have been registered for each month of the 

 drift of the Fram, and the monthly averages taken and smoothed for the 

 four seasons and the year. The following Table shows the result of this 

 computation. 



