ON EIGHT BALLOON ASCENTS IN 1862. 473 
§ 7. Comparison oF THE TEMPERATURE OF THE DEW-POINT, AS DETERMINED BY 
DIFFERENT INSTRUMENTS. 
Every simultaneous or nearly simultaneous determination of the dew- 
point by the different instruments or methods was copied out, and then all 
those determinations between every 1000 feet of elevation were collected 
together, and in this way the first five columns of the following Table were 
formed. The numbers in the last six columns were formed by taking the 
differences between the temperatures of the respective dew-points in the same 
horizontal line, or those taken at about the same height and elevation. 
Taste [X.—Showing the Temperature of the Dew-point, as determined at 
about the same height by different instruments and methods, and compa 
rison of the results together. 
Under 1000 feet. 
Dew-point Temperature of the Dew-point as deter- 
Temperatures mined by 
Dry and Wet] 5 
Calculated Observed D d Wet (fi by = 
ae by |) "above that by > | Campirated) | a. 
Date. 12 Ct i | as [ST eee) So 
s SA 5 5 || SA a|is K 5 | Eos 
Be | Ee) we | Se | Fe] -t | S2| 3 | Se [eee 
BE | 22/26) 28 || 22) 36/26) 32 | 28 |3e° 
p | ba | eB) Bel pe) eh) S| gE) Bele 
a =) AS) em) ar~|at | aa / am | ratia 
d h m feet. ° ° ° ° °o ° ie) ° ° 
July 30 4 36 | 250 | 50°0 50°0 | o'o 
4 423| 890 | 44°9 44°0 Tee 
Aug. 18 0 56 | 490 | 55°0 | 54°6| 55°0 53°9 +04) oo|+1'1|—0'4|40'7)4+11 
zo 6 5] 250 | 56'7 55°5 +12 
Sept. 1 440 | 250 | 56'5 52°0 +4°5 
453 | 320) 519 52°0 en 
5 © 9} 490 | 49°5 | 49°9| 49°°) 45°5 —0'4)+0°5 /+4°0|+0'9 |4+4°4 |+3'5 
8 5 43 | 887 | 59°9 58°5 +14 
Between 1000 and 2000 feet. 
513 52°71 
49°3| ++ | 4970 
50°3 50°5 
50°5| «+ | 4g'0 
478 50° 
49'0 47°5 
566 5570 
