200 
MR. GLAISHER ON THE RADIATION OF HEAT 
Table Cl. — Showing the mean monthly excess of the reading of a self- 
registering minimum thermometer in Air at the height of 4 feet, above the 
General state of the 
sky during the night 
previous to reading 
the instruments. 
Year. 
Month. 
The mean excess 
the readings of a 
in each month, according to the state of the sky with respect to the quantity of cloud, of 
self-registering minimum thermometer placed in air at the height of 4 feet and protected 
On long grass 
exposed to |ths 
of the sky. 
On long grass. 
On short grass. 
On garden 
mould. 
In air one inch 
high. 
In air three 
inches high. 
Mean 
excess. 
Number 
of 
nights. 
Mean 
excess. 
Number 
of 
nights. 
Mean 
excess. 
Number 
of 
nights. 
Mean 
excess. 
Number 
of 
nights. 
Mean 
excess. 
Number 
of 
nights. 
Mean 
excess. 
Number 
of 
nights. 
Cloudless. 
1843. 
April. 
o 
8-1 
i 
o 
8-5 
l 
5-6 
3 
8-6 
i 
7-9 
i 
May. 
60 
2 
10-2 
2 
40 
2 
11-4 
2 
7-7 
2 
June. 
6-5 
7 
9-7 
7 
5-5 
7 
10-5 
7 
11-3 
7 
July. 
7-4 
2 
12-7 
2 
100 
1 
120 
2 
10-0 
2 
August. 
5-8 
6 
10 6 
6 
10-8 
6 
10-9 
6 
September. 
7-1 
4 
ii-4 
7 
100 
11 
8-8 
11 
6-9 
11 
October. 
8-0 
8 
6-4 
8 
5-3 
8 
November. 
9'9 
6 
80 
6 
6-3 
1 
December. 
* 
0 
0 
0 
1844. 
January. 
9-5 
2 
9-9 
1 
February. 
9-6 
4 
71 
4 
March. 
8-3 
7 
6-2 
7 
April. 
11-8 
18 
10-7 
18 
May. 
11-3 
10 
10-6 
10 
June. 
9-3 
7 
8-0 
7 
July. 
10-9 
12 
91 
12 
August. 
8-9 
12 
7-6 
12 
September. 
10-5 
12 
87 
12 
October. 
10-7 
8 
8-7 
8 
November. 
101 
2 
5-4 
2 
December. 
110 
6 
7-2 
6 
... 
Principally clear. 
1843. 
April. 
... 
110 
2 
2-3 
2 
May. 
4-5 
7 
5-0 
7 
3-3 
7 
7-6 
7 
6-7 
7 
June. 
3-5 
7 
6-0 
7 
2-9 
7 
8-3 
7 
7-9 
7 
July. 
5-9 
10 
5-9 
10 
7-0 
1 
71 
9 
7-3 
10 
August. 
4-7 
12 
7-1 
12 
6-9 
12 
7-2 
12 
September. 
7-4 
1 
8-8 
2 
9-7 
5 
91 
5 
9-5 
5 
October. 
8-0 
8 
71 
8 
5-9 
8 
November. 
8-9 
7 
6-2 
6 
4-4 
4 
December. 
71 
5 
6-5 
4 
1844. 
January. 
8-5 
7 
7-4 
7 
February. 
7-5 
6 
5-8 
6 
March. 
6-6 
2 
5-6 
2 
April. 
10-3 
4 
9-1 
4 
May. 
9-8 
5 
9-5 
5 
June. 
8-8 
5 
90 
5 
July. 
8-8 
1 
100 
1 
August. 
8-1 
6 
6-0 
6 
September. 
10-8 
4 
9-9 
4 
October. 
9-5 
6 
8-1 
6 
* . . 
November. 
9-6 
7 
7-2 
7 
December. 
7-2 
1 
5-7 
1 
Half-cloudy. 
1843. 
April. 
4-7 
1 
6-2 
3 
3-3 
3 
4-7 
1 
4-2 
1 
May. 
41 
4 
6-6 
4 
4-2 
4 
71 
4 
7-6 
4 
June. 
3-8 
1 
73 
1 
40 
1 
10-8 
1 
10-6 
1 
July. 
3-8 
7 
6-2 
7 
4-5 
1 
5-9 
7 
6-4 
7 
August. 
4-5 
7 
60 
7 
5-6 
7 
6-0 
7 
September. 
4-7 
2 
9-4 
5 
8-1 
7 
6-5 
7 
4-8 
7 
October. 
6-3 
6 
5-6 
6 
4-8 
6 
33 
1 
November. 
45 
7 
5-6 
6 
3-8 
1 
December. 
71 
1 
61 
1 
1844. 
January. 
7-4 
5 
5-9 
5 
February. 
6-2 
6 
4-6 
6 
March. 
6-5 
9 
4-7 
9 
April. 
6-2 
3 
60 
3 
May. 
5-5 
9 
5-4 
9 
June. 
7-7 
7 
7-6 
7 
July. 
9-7 
5 
6-8 
4 
August. 
8-4 
4 
6-4 
4 
September. 
10-5 
12 
8-7 
12 
October. 
7-6 
6 
6-7 
6 
November. 
8-0 
6 
6-4 
6 
December. 
0 
0 
