THE BAHAMA ISLANDS 



139 



graph tracings were averaged for each 100 feet of elevation, and these aver- 

 ages in turn grouped in order to obtain average values for each successive 

 column of 500 feet. In the following table these values are reproduced; 

 the average humidities are also shown graphically in curve (c) of Fig. 6. 



As will be seen by inspection of the percentages of relative humidity, 

 there is a steady increase from the surface to the highest elevations reached, 

 namely 4000 feet, excepting the layer between 2500 feet and 3000 feet, where 

 there is an interruption to the steady increase. The drop from 93 per cent 

 to 89 per cent near the 3000-foot level is probably due to an excessive value 

 just below the 2500-foot level, brought about by the kite passing through a 

 cloud at this leveLon three or four occasions. 



INCREASE OP RELATIVE HUMIDITY ; AVERAGE OF POUR ASCENTS. 



Elevation. 



Feet. 

 Surface. 

 0-500 



500-1000 

 1000-1500 

 1500-2000 

 2000-2500 



Number of Relative 

 observations, humidity. 

 Per cent. 



10 

 5 



12 

 15 

 16 

 18 



73 

 79 



82 

 84 

 87 

 93 



Elevation. 



Feet. 



2500-3000 

 3000-3500 

 3500-4000 



Number of Relative 

 observations, humidity. 



Per cent. 

 9 89 



1 95 



88 



96 



86.3 



TABULATION OF OBSERVATIONS. 



The observations obtained during the various flights described above are 

 tabulated below. 



OBSERVATIONS AT NASSAU, JUNE 27, 1903. 



* 6 cumulus, 10 a. m. to noon. Average pressure decrease 0.10 inch per 95 feet. Average 

 temperature decrease 1 F. per 112 feet. Figures in italic are interpolations. 



