296 REPORT— 1861, 



The numbers In this Table show, as in all the previous experiments, that 

 the moisture of the air at the same elevation is very different at diiferent 

 times ; and that on the same day the moisture is very differently distributed, 

 there having been on some of the days of experiments several successive "wet 

 and diy strata placed one above the other. 



The numbers in the last columns show the average results at the different 

 elevations, in the two states of cloudy and clear skies, and the number of ex- 

 periments upon which each result is based. 



By combining those with a cloudy sky with those previously obtained, 

 according to the number of observations upon which each value was based, 

 the followiag results were obtained : — 



With an overcast sky the degree of | 74 f^^^ ^^ ^^ ^^^^^^s. 



hiunidity on the earth was J '■ 



At 1000 feet 76 „ 33 „ 



2000 „ 76 „ 34 



3000 „ 78 „ 35 



4000 „ 75 „ 27 



5000 „ 74 „ 16 



6000 „ 73 „ 14 



7000 „ C2 „ 11 



8000 „ 54 „ 11 



9000 „ 50 „ 11 



10,000 „ 48 „ 10 „ 



11,000 „ 47 „ 10 



12,000 „ 52 „ 6 



13,000 „ 58 „ 6 



14,000 „ 52 „ 5 



15,000 „ 59 „ 3 



16,000 „ 59 „ 2 



17,000 „ 47 „ 2 



18,000 „ 33 „ 2 



19,000 „ 24 „ 2 



20,000 „ 29 „ 2 



21,000 „ 22 „ 2 



22,000 „ 34 „ 1 



23,000 „ 40 „ 1 „ 



The law of moisture here shown is a slight increase from the earth to the 

 height of 3000 feet, and then a slight decrease to 6000 feet, the degree of 

 humidity being at this elevation nearly of the same value as on the ground. 

 From 6000 to 7000 feet there is a large decrease, and then an almost uni- 

 form decrease to 11,000 feet; it increases from 12,000 to 16,000 feet, and 

 then decreases. The number of experiments up to 11,000 feet vary from 10 

 to 35, and I think great confidence may be placed in the results to this ele- 

 vation ; but at heights from 12,000 feet the number of experiments are evi- 

 dently too small to speak -with any confidence in respect to the results. 



By treating the results with a clear or a nearly clear sky in the same way, 

 the following results were obtained. 



