ON FIVE BALLOON ASCENTS IN 1868. 483 
feet. ‘ 
feet feet = 
From 0 to 1,000 the decrease was 7:2, or 1° on the average of 139 
12: 
2» 2,000 ” ” 164 
” 3,000 » 16:2 9» 186 
a: 4,000 coals lee i 207 
. 5,000 22-1 3 227 
" 6,000 E 24-7 4 243 
“ 7,000 27:3 is 257 
45 8,000 3 29°8 i 269 
: 9,000 . 32:3 f 278 
ot OO :. 34:8 vr 288 
2 | 91.600 é 37:3 a 295 
» 12,000 f 39-8 302 
» 18,000 : 42-2 : 308 
» 14,000 e 44-4 e 316 
» 15,000 . 46:5 y 323 
» 16,000 4 48:5 if 331 
4: +17,000 3 50-4 as 338 
» 18,000 . 52-1 * 346 
» 19,000 ra 53-6 4 356 
» 20,000 ps 54-9 ‘. 365 
» 21,000 rd 56-1 : ). 3s 
» 22,000 ke 57-2 " 385 
» 23,000 : 58-0 “, 396 
» 24,000 A 59:3 “ 406 
~~ 25,000 Hl 60-4 i 416 
» 26,000 61-4 e 425 
27,000 i 62-4 & 434 
sy 28,000 : 63°3 b 444 
» 29,000 4 64:1 is 454 
» 80,000 } 64-6 ss 464 
These results, showing the whole decrease of temperature from the ground 
to 30,000 feet, differ greatly, as just mentioned, from those with a cloudy sky. 
The numbers in the last column, showing the average increase of height for 
a decline of 1° of temperature from the ground to that elevation, are all smaller 
than those with a cloudy sky at the same elevation. Each result, up to 
22,000 feet, is based upon at least six experiments, taken at different times 
of the year, and up to this height considerable confidence may be placed in 
the results; they show that a change takes place in the first 1000 feet of 1° 
on an average of every 139 feet, increasing to about 300 feet at 11,000 or 
12,000 feet ; in the experiments taken in the year 1862, this space of 300 
feet was at 14,000 feet high, therefore the changes of temperature have been 
less in 1863 than those in 1862. The latter experiments, however, have 
been taken at different times of the year from those of the former, and 
it would seem probable that this element varies with the season of the year. 
Every experiment proves that the theory of a decline of 1° for every in- 
crease of 300 feet must be absolutely put on one side, as without exception 
the fall of 1° has always taken place in the smallest space when near the 
earth. To determine this space, and also the law of decrease near the earth, 
all the observations of temperature of the air up to 5000 feet were laid down 
on large diagrams, and a line was made to pass through them, giving equal 
weight to every observation; the result at every 200 feet was then read out, 
and in this way the next series of Tables were formed. 
212 
