SEVENTH ANNUAL MEETING 



93 



that the vapour pressure varies directly with the temperature 

 although not at the same rate. 



The distribution of the relative humidity, amount of cloudi- 

 ness and frequency of precipitation are shown in figures 17, 

 18 and 19 respectively. The relative humidity is expressed in 

 per cent ; the amount of cloudiness is given in the usual scale 

 of 1 to 10; and the frequency of precipitation is also expressed 

 in per cent. The three diagrams are strikingly similar. On 

 the whole it is seen that the values of these three quantities 



Figure 18. Amount of Cloudiness 



are greater in the northern half of the cyclone than in the south- 

 ern half. The lowest values occur farthest to the southeast of 

 the center. The highest values are found in the dark areas im- 

 mediately north and slightly west of the center of the cyclone. 

 These areas are relatively small and sharply defined. Judging 

 from the close coincidence in the distribution of the relative 

 humidity, amount of cloudiness and frequency of precipitation, 

 it appears safe to assume that the amount of precipitation fol- 



