180 



Report — 18G5. 



Table VII. (continued). 

 Twenty-fourth Ascent (continued). 



December 30. — The temperature of the dew-point on the ground was 34°-9, 

 and the humidity 74, the former decreasing to 31 §° at 600 feet, where the 

 humidity was 72 ; the dew-point then varied but little, and much less than 

 the temperature of the air, so that the degree of humidity increased to the 

 height of 2400 feet, then was smaller at 2600 feet. The balloon descended 

 then to 2000 feet, then turned to ascend ; the air continued humid till 3200 

 feet was passed ; the degree of humidity at this point was 94 ; above this point 

 the air was much drier. During the subsequent successive ascents and descents 

 the air in the lower atmosphere was found to be very humid. 



February 27. — The temperature of the dew-point on the earth was 38°, or 

 14°-3 below that of the air, the air being consequently unusually dry, and 

 particularly so for February, the degree of humidity being 59 only. On 

 ascending, the air gradually became more moist, till the height of 3200 feet 

 in the centre of cloud, where the degree of humidity was 78. On leaving 

 the cloud below, the air became drier, and was the driest at 5000 feet high, 

 where it was 37. On descending, the air was much drier down to 2600 feet 

 than at corresponding heights during the ascent. No cloud was passed 

 through, and at lower elevations the air was more moist than in the ascent. 

 On ascending again through cloud, and descending also through cloud, the 

 results were very similar to those noted in the first ascent, the most humid 

 states being those in the cloud, which in the last descent were found but 

 little short of saturation. 



