85 
and the Mode of its Communication . 
is reckoned from the same height, or given number of degrees 
above the temperature of the air at the time when the experi- 
ment is made, will appear from the following results of 11 
different experiments, made on different days, and when the air 
in which the instrument was exposed to cool w r as at different 
degrees of temperature. 
The large cylindrical vessel, No. 1, having its two ends well 
covered up with eider-down, furs, &c. its vertical sides being 
exposed naked to the air, in a large quiet room, was found to 
cool 10 degrees, viz. from the 50th to the 40th degree above 
the temperature of the air in which it was exposed, as follows. 
Temperature 
Time employed 
of the air. 
Degrees cooled. 
in cooling. 
44 ° - 
- 
from 
O 
OO 
0 
55 minutes. 
45 i - 
- 
- 
95 i to 85J 
55 |- 
48 
- 
- 
98 to 88 
" 55 + 
S'i “ 
- 
- 
ioii to9ii 
“ “ 55 i 
52 
- 
- 
102 to 92 
" - 55 
54 - 
- 
- 
104 to 94 
■'f 
1 
1 
44 
- 
- 
94 t0 8 4 
“ “ 55 f 
4 >H - 
- 
- 
9 2 i to 824- 
55 t 
45 
- 
- 
95 to 85 
- - 56 
4 6 - 
- 
- 
96 to 86 
“ " 55 
44 " 
- 
- 
94 to 84 
- " 55 f 
The fact which these experiments are here brought to prove, 
has likewise been confirmed by other experiments, made with 
other instruments, and at times when the temperature of the air 
has been as high as 64°; but I v/ill not take up the time of the 
Society, by giving a particular account of them in this place. 
As it sometimes happened, though very seldom, in the course 
