ON EIGHT BALLOON ASCEN'TS IN 1862, 481 
TasLe XI.—Comparison of the Readings of Mercurial and Aneroid Barometers, 
in the ascents on July 17 and August 18. 
, Excess of 
i : E f | 
| eatings of | ending o Readings of |esiiny a | 
Month, day, hour Barometers. Aneroid Month, day, hour Barometers. ‘Anactidine 
| Siphon ini ge |... | Siphon 
| 
| 
and minute. f above and minute. above 
Siphon. |Aneroid.| Barometer. Siphon. |Aneroid.| Barometer. 
in. in, | in. in, | in. 
m= s} in. 
July 17, 9 49 0 25°22] 25°32 toro | Aug. 18, 0 56 0} 29°34| 29°51] torr7 | 
9 51 24°14] 24°30] +0°16 || 6 0, 28°55) 28°78} +023 | 
9 53 22°42 | 22°65! +0°23 8 9 26°67 | 26°90} +0°23 
9 54 22°02 | 22°20} +o18 Io o| 25°86) 26°08) +022 
9 55 09} 21°58) 21°80] -or22 || 14 0} 23°64] 23°82] +0-18 
9 56 20°93| 21°10) +o'17 || 15 22°69 | 22°68| —oro1 | 
9 58 19°63 | 20°09| 40°46 | 20 19°90| 20°05 | +ors5 | 
Io 2 19°28 | 19°60} +0732 | 24. 15) 20°90| 21°28 | +038 
s h 
fo) ° 
Co) I 
QO} I 
) I ° 
° I ° 
° I ° 
° I oO} 
° | I 5 
Io 3. o| 18°63| 18°90) +0'27 \ 127 0} 22°62! 22°90] +0°28 
Io § oj 1814} 18:40) +026 | I 32 0} 22°80| 22°85] +o'o5 | 
to 8 of 17°24] 17°52| +0'28 || I 38 0} 24°46] 24°60) +o14 | 
IO Ir 0} 16°74! 17°10} 40°36 || I 41 0} 25°08! 25°30! +o'22 
TO 15 oj 16°04] 16:25] +ora1 || I 52 0! 25°80} 25°82) +o'02 
To 25 0} 14°94| 15715) +o'21 || 155 0} 25°08 | 25°25) +017 
Io 27 oj 14°64) 15°30) +0°66 || 2 © O} 23°93} 24°10] +017 
Io 29 oj 14°64] 15°30| +0°66 2 g Of 22°58| 22°71} +013 
IO 30 o} 14°64} 15°30} +0°66 2 17 0} 20°24] 20°50] +0:26 
IO 35 | 14°64] 15°00} +0°36 | 2 21 0} 19°11} 19°30| +orrg 
IO 44 0} 14°63) 15°10] +-0'47 || 2 25 20) 17°61| 17°85} +024 
10 47 0) 14°13) 14°70) +0°57 || 2 29 0} 16-41 16°50! + 0°09 
IO 50 o} 13°64] 14°20] +0°56 2 32 20] 15°84.) 16:00! +016 
IO 54 0} 13°14] 13°60| +046 2 49 50| 13°70} 13°60} —o'ro 
IO §7 | 12°14| 12°60) +0'46 3 5 | 12°93} 13°20) 40°27 
II 3. of 11°64 12°10] + 0°46 3 18 30) 13°45] 13°55) +-o"lo 
II 7 of 11°65] 12°10} +045 3.25 0} 13°65| 13°72] +0°07 
II 12 ©} 11°95| 12°40] +0°45 3.34 +) 17°53] 17°42] —o'11 
II 20. o} 12°65} 13°20} + 0°55 3 36 o| 18°63] 18°65] +0'02 
II 25 0} 13°14| 13°60} +046 3 39 0} 20°02| 20°05} 40°03 
II 38 0} 18°94| 19°00| -++0°06 3.49 0} 24°28) 24°42] +014 
II 39 0} 20°04} 20°40] +0°36 
II 40 0} 20°54 20°80; +0°26 
July 17.—The differences between the readings are shown in the last 
column, and exhibit an increasing difference, increasing in amount with 
decreasing readings, till at the highest point the discordance between the 
readings amounted to half an inch. It is presumed that the aneroid baro- 
meter was in error to these amounts; but both instruments were broken in 
the descent, and no more information can be given. 
August 18.—The differences between the readings of the mercurial and 
aneroid barometers in this ascent were as constant as could be expected, as 
the readings could seldom be strictly simultaneous. Upon the whole, the 
readings of the aneroid are as good as those of the siphon. 
1862, Ox 
