ON THREE BALLOON ASCENTS IN 1864) AND 1865. 



171 



Table III. — Showing the Temperature of the Air, as read off the curve 

 drawn through the observed temperatures, and as read off the curve of 

 most probable normal temperatures, called adopted temperatures, and the 

 calculated amount of disturbance from the assumed law of decrease of 

 temperature. 



Twenty-third Ascent. 



December 1.— The temperature of the air at the height of 400 feet was the 

 BMne as on the ground, viz. 48°; on passing above this point the temperature 

 declined to 47|° at 600 feet, very slowly to 45|° at 1600 feet ; a decrease of 

 1 |° then took place in the next 200 feet, remained very nearly the same for 

 400 feet more, and then declined to 41^° at 2600 feet, still decreasing gradu- 

 ally to 38^° at 3800 feet, and then rather more quickly to 29^° at the 

 highest point. On descending, the temperature increased very uniformly 

 till 4000 feet was passed, then almost without change through a decline of 

 800 feet, or to 3200 feet high ; increased 1° in the next 400 feet downwards, 

 and 1^° in the succeeding 200 feet; after this the temperature increased by 

 pretty even amounts, till the height of 1800 feet was reached ; here a warm 

 current was entered, for by the time the balloon had descended to 1400 feet, 

 the temperature had increased to 41|°; it then declined to 41° at 1000 feet' 



