ON EIGHT BALLOON ASCENTS IN 1862. 443 
Eien Ascent.—September 8 (continued). 
Time of |Reading of} Height Temp, || Ti i Hei : 
observa- |the Bardi. above the ee of the aoe rep een eye oar Bre 
tion. reduced to| Jevelof | %..'° ew- tion. reduced to| level of of the Dew- 
P.M. 32°F, thesea. ; point. P.M. 32° F. the sea. a point. 
hm s|-in. feet. a a hm s| in feet. a S 
5 57 30} 23°38 1639 | 60°5 | 55°83 || 6 x 30) 27°98 | 2034 | 59°8 | 54° 
58 of 28-22 1798 | 600 | 56:2 I 45| 27°90 2114 | 59°8 | 54°8 
58 40] 28:11 | (1870) | 60°0 | 56°6 2 ©} 27°90 2114 | 59°8 | 54°9 
6 © oO} 28:05 1967 | 60°5 | 56:0 3 40) 27°78 2235 59°5 | 50°0 
© 20] 27°98 2034 | 60°0 | 57°1 5 oO] 27°89 2122, | §9'2.1 §57°0 
I of 27°98 2034 | Goo | 55°8 IO 0} 30°07 on the 
ground 
§ 5. Varration or TEMPERATURE OF THE ATR witH Heteur. 
In order to arrive at an approximate value of the normal variation of tem- 
perature on each day, it is necessary to make some estimate of the amount of 
the disturbing causes. 
For this purpose I placed every reading of temperature in the preceding 
Tables in the high ascents, or the means of small groups of observations in the 
low ascents, on diagrams, and joined all the points, and caused a curve to pass 
through or near them, so that every change of temperature was thus made 
evident to the eye. 
In all these projected curves there were parts of evidently the same curve 
showing a gradual decrease of temperature with increase of elevation, and a 
gradual increase with decrease of elevation. These parts were connected and 
assumed to be a close approximation to the truth, and capable of giving approxi- 
mate values of the normal variation of temperature with height. The departure 
in the projected curve of observed temperatures from the assumed curve of 
normal temperatures in these diagrams indicated the places and the amounts of 
disturbance. The next step was the reading from these curves the tempe- 
rature 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 interval 
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 temperature of the air ; 
and those in the next column the difference between the two preceding 
columns, or the most probable effect of the presencé 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. 
