ON NINE BALLOON ASCENTS IN 1863 AND 1864. 



269 



Table III. (continued.) 

 Seventeenth Ascent. 



Janviary 12. — The temperature of the air before starting was 41|°; it de- 

 creased very slowly till 1300 feet was reached, a warm current was then met 

 with, and at 3000 feet the temperature was nearly 45°, being 3|° higher than 

 on the ground, and for a space of 3000 feet in height the temperature was 

 higher than on the earth; it then gradually declined to 11° at 11,500 feet, 

 and remained at about this degree till the highest point was reached ; on de- 

 scending it gradually increased with decrease of elevation, tiU on reaching 

 the ground at 4" 10"" it was 41°-8. The results on this day are so remark- 

 able that no adopted temperature has been attempted. 



April 6. — This ascent is remarkable for the small decrease of temperature 

 with increase of elevation. The temperature of the air was 45|° on leaving 



