394 



REPORT — 1864. ■ 



Table VII. (continued.) 



Twenty-first Ascent. 



1864. 



Height, in feet, 

 above the mean 

 level of the sea. 



Humiditv of the Air. 



Between 

 what 

 times. 



June 27. 

 5000 

 4000 

 3000 

 2000 

 1000 

 o 



4000 

 3000 

 2000 

 1000 

 o 



Ascending, 



Circum- 

 stances. 



2 '^a 



'dp- 

 00 "^ 



Tempe- 



ratvire of 



the dew 



point. 



Elastic 

 force of 

 vapour. 



38-5 

 382 



40-5 

 40'2 



44" S 



35-6 

 367 



35-4 

 37'o 



Degree 



of 

 humi- 

 dity. 



Descending. 



in. 



■233 

 •231 

 ■252 

 •249 

 •294 



•208 

 •218 



•207 

 •220 



86 

 81 



71 

 63 

 64 



70 

 68 



65 

 64 



Between 

 what 

 times. 



Circum- 

 stances. 



Tempe- 

 rature of 

 the dew- 

 point. 



B-3 o 



38-5 



35"3 

 383 

 40-5 



38-3 



Elastic 

 force of 

 vapour. 



ni. 



•233 

 •206 

 •231 

 ■232 

 •231 



Degree 



of 

 humi- 

 dity. 



87 

 78 

 84 

 78 

 67 



Twenty-second Ascent. 



August 29. 

 14000 

 13000 

 12000 



IIOOO 

 lOOCO 



9000 

 8000 

 7000 

 6000 



5000 



4000 

 3000 

 2000 

 1000 

 ground. 



25 

 24 



32 



41 



54 



79 



42 



38 



79 

 78 

 74 

 79 

 55 

 53 

 47 



decreased to 8°, but on attaining 3520 feet it was 11|^°, and at 4000 feet the 

 temperatures of the air and dew-point were 45° and 35g° respectively, showing 

 a difference of 9|°, and a humidity of 70°. 



August 29. — The differences between the temperatures of the aii" and those 

 of the dew-point in this ascent were rather remarkable ; on starting it was very 

 large, viz. 27°, their respective readings being 721° and 45-l-°, and the degree 

 of humidity 38. The difference decreased veiy gradually till 4500 feet was 

 gained, when the air became suddenly moist, the difference only amounting to 

 6-1-° at 5600 feet, then became dr)^, and continued so till 11,000 feet was 

 reached, the humidity being 56 ; after which it increased in dryness till the 

 difference equalled 23° at 13,000 feet, the humidity having decreased to .37; 

 it was moderately moist at the highest point, the difference there being 9°. 



On descending, at 14,000 feet the air became veiy suddenly dry, the differ- 

 ence between the two temperatures increasing from 9° to 32° in a minute and a 

 half, and the humidity being 25 ; it then declined to 6° at 9100 feet, increased 

 again to 23° at 7350 feet ; decreased to 6|° by 4550 feet, after which it in- 

 creased to 21° on the ground, where the degree of humidity was 47. 



