ON NINE BALLOON ASCENTS IN 1863 AND 1864. 2111 



Cleak Sky. 



By adding together the numhers in column 31 in the same way the 

 following results are found : — 



feet feet o fee'- 



From to 1,000 the decrease was 6-2, or 1° on the average of 1G2 



2,000 „ 10-9 „ 184 



„ 3,000 „ 14-7 „ 204 



„ 4,000 „ 18-0 „ 223 



.5,000 „ 20-9 „ 239 



6,000 „ 23-5 „ 256 



7,000 „ 26-0 „ 271 



8,000 „ 28-7 „ 279 



„ 9,000 „ 31-2 „ 289 



„ 10,000 „ 33-6 „ 298 



„ 11,000 „ 35-6 „ 309 



„ 12,000 „ 37-9 „ 317 



13,000 „ 40-1 „ 324 



14,000 „ 42-1 „ 333 



„ 15,000 „ 43-8 „ 343 



„ 16,000 „ 46-0 „ . 348 



„ 17,000 „ 47-9 „ 355 



18,000 „ 49-6 „ 363 



„ 19,000 „ 51-1 „ 372 



„ 20,000 „ 52-4 „ 382 



„ 21,000 „ 5y-6 „ 392 



„ 22,000 „ 54-7 „ 405 



„ 23,000 „ 55-7 „ 413 



„ 24,000 „ 57-0 . „ 422 



„ 25,000 „ 58-1 „ ' 431 



26,000 „ 59-1 „ 441 



„ 27,000 „ 601 „ 449 



„ 28,000 „ 61-0 „ 459 



„ 29,000 „ 61-8 „ 469 



30,000 „ 62-3 ,, 482 



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 is based 

 upon at least seven experiments, taken at different times of tlie 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 102 

 feet, increasing to about 300 feet at 10,000 feet ; in the year 1802 this space 

 of 300 feet was at 14,000 feet high, and in 1863 at 12,000 feet high, there- 

 fore the changes of temperature haTe been less in 1863 than those in 1862, and 

 also less in 1864 than in 1863 ; but the experiments have all been taken at 

 different times of the year. 



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 de- 

 crease 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 tlnough 

 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. 



