7 
with a Method of measuring the Dip at Sea . 
also the degrees of cold produced by keeping the bulb of it 
moistened for a sufficient time to render it stationary. In con- 
firmation of my conjecture respecting the dryness of Oct. 22, 
I have also, in the following Table, which comprises the whole 
of my observations, inserted a column from the Register kept 
at the apartments of the Royal Society, containing the heights 
of the hygrometer, on those mornings when my observations 
were made. 
Table. 
At 8, A. M. 
Air. 
Water* 
Difference. 
Refraction. 
Cold by 
evaporation. 
Hygro- 
meter. 
1800. Sept. 23 
57 
&> 4 ° 
34 ° 
- 4 ' 
_ 
72 0 
Oct. 1 7 
4^4 
4 94 
3 
3 
72 
22 
38 
4 94 
i *4 
3 
— 
67 
Nov. 1 
41 
4 54 
44 
8 
i° 
2 
7 6 
4 
43 i 
4 ^i 
3 
3 ~ 
72 
5 
37 
45 
8 
8 + 
1 
69 
12 
444 
48! 
4 
1 + 
34 
73 ' 
13 
4 ° 
444 
44 
5 
*2 
76 
1801. June 13 
5 ° 
6g 
t 3 
9 + 
5 
6 5 . 
22 
55 
61 
6 
6 + 
6 
^5 
23 
55 
6 2 
7 
6 
44 
^5 
24 
55 
61 
6 
5 
3 
67 
Sept. 8 
60 
64 
4 
7 
2 
78 
9 
64 
6 4 i 
3 
4 
5 
3 
74 
10 
58 
64 
6 
7 
2 
70 
12 o’clock, 10 
6s 
64 
1 
2 
From a review of the preceding Table it will be found, upon 
the whole, that when the water is warmer than the air, some 
increase of depression of the horizon may be expected; but 
