276 REPORT— 1864. 



Ill the liist column of Table IV. the same results are sliowu for clear, or 

 nearly clear skies, and tlie}- sliow that a change of 1° takes place for an average 

 increase of 162 feet ; this space gradually increasing to 1000 feet at 23,000 

 feet. 



By comparing the numbers in columns 30 and 33 together, the different 

 spaces required to be passed through for a decline of 1° of temperature in the 

 two states of the sky wiU be readily seen : up to 23,000 feet it is necessary 

 to pass through a much larger change of elevation with a cloudy sky for a 

 decline of 1° of temperature than with a clear sky. 



Cloudy Sky. 

 By adding together successively the numbers in column 28, we shall find 

 the whole decrease of temperature from the earth to the different elevations ; 

 the results with a cloudy sky are as follows : — 



feet feet o feet. 



Prom to 1,000 the decrease was 4-5, or 1° on the average of 223 

 2,000 „ 8-1 „ 247 



„ 3,000 „ 11-8 „ 255 . 



4,000 „ 15-2 „ 263 



5,000 „ 18-5 „ 271 



6,000 „ 21-7 „ 277 



7,000 „ 24-4 „ 287 



8,000 „ 26-8 „ 299 



9,000 „ 29-0 „ 311 



10,000 „ 31-2 „ 321 



11,000 „ 33-4 „ 329 



12,000 „ 35-6 „ 337 



„ 13,000 „ 37-8 „ 344 



14,000 „ 40-1 „ 349 



15,000 „ 42-1 „ 356 



„ 16,000 „ 44-2 „ ~ 362 



17,000 „ 45-4 „ 375 



18,000 „ 46-7 „ • 386 



19,000 „ 48-1 „ 395 



20,000 „ 49-0 „ 409 



21,000 „ 50-1 „ 419 



22,000 „ 50-9 „ 432 



23,000 „ 51-7 „ 445 



These results, showing the whole decrease of temperature of the air from 

 the earth up to 23,000 feet, differ very considerably from those with a clear 

 sky, to be spoken of presently. Tlie numbers in the last column show the 

 average increment of height for a decline of 1°, as found by using the tempe- 

 ratures of the extremities of the column above. To 1000 feet high the average 

 is 1° in 223 feet, increasing gradually to 1° in 445 feet at 23,000 feet. 



