hie meh a} in feet. 
ON FIVE BALLOON ASCENTS IN 1863. 475 
Taste II. (continued).-—Eeventx Ascent.—June 26 (continued). 
! 
Time of |Reading) peicht poring 
Temp. | Temp. || Time of Height Temp. | Temp. 
observa- Bs -d the above the chp of the | of the || observa- ue above the Hey of the | of the 
tion a er level of | ‘Ai ©! wet- | Dew- tion. seAbie ad level of Air Wet- | Dew- 
P.M. me 39° F. the sea. T+ | bulb. point. P.M. to 32° F. the sea. * | bulb. | point. 
| 
° a = o hm s|} in. feet. = a 
2 10 45/ 15°54 | 17888 | 29°5 | 24°5 75 || 2 16 30) 20°05 |... 6: | 33°0 | 2775 | 16:4 
II 16:04 | 17422 | 29°5 | 24°5 F ia 17 20°44 | 10508 | 33°0 | 27°0 | 34'9 
II 15) 16°24 | 16776 | 31-0 18 20°77 | IOOIT | 33°0 | 26°5 | 1374 
II 30) 16°35 | 16594 19 20°77 | IOOII | 33°5 | 260 | 11°8 
BOE OAG LAG sos esies @) 3E°5 2670, |- 12-2 19 30)20°89 | 9917 
12 16°44 | 16412 | 32°0 | 262 | 1271 19 45)21'29 | 9402 
22 Bolo... 3 bowen (|'32°5 ||| 26:2 | 226 20 20/2149 | 9148 | 33°5 | 260 | 311'8 
13 16°84 | 15762 | 32°0 | 27°0 | 154 20 30) 22°33 8107 | 34°5 | 27°2 | 14°9 
13 15) 16°95 | 15602 | } 2% 24°25 | (5870) | 38:0 
13 30} 16°99 | 15521 |31°5 | 27°70 | 15-7 || 22 24°72 | 5319 | 39°2 | 33:0 | 24:8 
14 17°39 | 14892 | 33°0 Iw 23 Senta sss |42°0 | 35"1 | 26°6 
2 ee “= 1|33°O |. 27°0 |\ t4°9 24. aisieta reese 143'0 | 37°70 | 29°8 
14 30/ 17°64 | 14501 | 25 25°81 | 4138 
14 45)17°84 | 14197 | 3370 | 25 30/2660) 3394 | 46:2 | 43:1 | 39°6 
14 50| 18-04 | 13896 | 33°0 |.29°2 | 21°6 26 26°70 | 3293 1470 | 43°0 | 385 
15 Baie 4 sse- |33°0 | 29°2 | 21°6 27 28°18 | 1810 
15 r0| 18°74 | 12865 | 33°70 27 30) 28°76 | .1259 
15 30) 19°04 | 12433 | 33°0 28 29°26 779 
15 45 Bas 11 9370 |) 29°%) -laarR 28+ | 30°10 | ground | 665 | 6o0°0 54°7 
16 19°77 | 11412 | 
The readings of the Gridiron thermometer were taken occasionally only in 
the twelfth and thirteenth ascents, as checks on the accuracy of temperature 
as shown by the dry-bulb thermometer, and no combination of readings is 
necessary in these ascents for adopted temperatures, &c., and therefore in 
subsequent calculations the readings as they appear in Table I. are used, 
§ 5. Variation or TEMPERATURE OF THE AtR witH Hetenr. 
Every reading of temperature in the preceding Tables, or the means of 
small groups of readings when observations have been taken near to each other, 
was laid down on diagrams ; all these points were joined, and a curyed line 
was drawn to pass through or near to them, giving them equal weight, and 
by this means every change was made evident to the eye. 
In all these curves there were parts of the same curve showing a gradual 
decrease of temperature with increase of elevation, and a gradual increase of 
temperature with decrease of elevation. The curve of which these were parts 
was assumed to be the true curve of normal temperature freed from disturbing 
causes, and the deviation from this curve indicated the places of disturbance 
and their amounts. The next step was the reading from these curves the tem- 
perature at every thousand feet, and in this way the next Tables were formed. 
The numbers in the first column show the height in feet, beginning at 0 
feet and increasing upwards; the numbers in the second column show the in- 
terval of time in ascending to the highest point; the notes in the third column 
show the circumstances of the observations; the numbers in the fourth and 
fifth columns the observations and the approximate normal temperatures of the 
air; and those in the next column the difference between the two preceding 
columns, or the most probable effect of the presence of cloud or mist on the 
temperature, or of other disturbing causes in operation. 
The next group of columns are arranged similarly for the descent, and the 
other groups for succeeding ascents and descents. 
