ON THREE BALLOON ASCENTS IN 1864 AND 1865. 



173 



Table III. (continued.') 

 Twexty-fourth Ascent (continued). 



December 30. — The temperature of the air was 42|° on the ground ; it 

 declined 1° in the first 200 feet ; 0°- 7 in the second; 0°' 9 in the third ; l°-0 in 

 the fourth ; l°-2 in the fifth, where it was 37°-8, or nearly 5° less than on the 

 ground ; it then decreased by amounts varying from |° to 1° in every 200 feet, 

 till 2400 feet had been passed, where the temperature was 32|°, declining to 

 32^° at 2600 feet. The balloon then turned to descend, the temperature re- 

 maining at nearly the same value, viz. 32°, for 400 feet, and increased \° on 

 falling to 2000 feet, when the balloon turned to ascend, the temperature de- 

 creasing very evenly up to 3400 feet : here a warm current was met with ; for 

 the temperature increased 2|° in passing from 3400 feet to 3600 feet, the tem- 

 perature there being 29|°. On descending, the temperature decreased to 28^° 

 at 3400 feet, and remained veiy nearly at that value for the next 800 feet, 

 but increased to 29° at 2400 feet and to 30° at 2200 feet; after this it in- 

 creased about ±° for every 200 feet, till the balloon had fallen to 1000 feet, 

 and 1|° whilst passing from that to 800 feet ; the balloon then turned to re- 

 ascend for the second time, the temperature remaining at 36° whilst passing 

 upward from 800 feet to 1400 feet 5 it then declined about i° in passing 

 through the next 200 feet, and remained nearly at that value till 2400 feet were 

 reached, and fell to 34^° at 2800 feet, when the balloon turned to descend, 

 the temperature increasing from 34° at 2800 feet to 38°-2 at 300 feet ; on 

 again ascending, the temperature did not vary until 600 feet was reached, but 

 declined to 37 0, 2 at 1200 feet, and gradually increased to 38°-4 on the ground. 



