TOTAL DAYLIGHT AT KEW AND PARA. 
565 
The following Table gives the results, and the curve, fig. 14, Plate XXI., exhibits the 
regular nature of the increase before and after noon. The curve is a symmetrical 
one, and exhibits a maximum at noon ; the dotted curve is the curve of mean chemical 
intensity for April at Kew, and the relation between these two intensities is as 52 '4 to 
313 - 3, or a ratio of 1 to 5 - 98. 
Mean time. 
No. of 
observations. 
Intensity. 
Mean time. 
No. of 
observations. 
Intensity. 
h m 
7 3 
11 
0-196 
h m 
12 54 
13 
0-981 
7 54 
11 
0-389 
2 5 
17 
0-820 
9 24 
8 
0-789 
2 54 
14 
0-664 
10 
1 
19 
0-871 
3 57 
7 
0-406 
11 
5 
27 
0-983 
4 49 
4 
0-223 
12 
1 
21 
1-028 
1 
In a future communication I propose to discuss the relation between the chemical 
intensity of direct and diffuse sunlight at Kew, Para, and Lisbon. 
Chemical Intensity of Total Daylight at Para, April 12th, 1866. 
Solar time. 
Chemical 
intensity. 
Condition of solar 
disk. 
Clouds. 
Temperature ° C. 
Dry. 
Wet. 
h m 
millims. 
9 30 
0-348 
Clouded; dull. 
9-10 
28-1 
25-7 
764-4 
9 45 
liain. 
9 55 
0-731 
9-10 
28-4 
26-4 
10 0 
Rain. 
10 25 
0-947 
Unclouded. 
8 
29-4 
28-3 
10 35 
Rain. 
10 55 
Id. 
11 2 
0-971 | 
Unclouded. 
7-8 
29-4 
27-3 
11 30 
1-019 
7 
31-1 
27-2 
11 55 
1-019 
Unclouded. 
5 
30-1 
25-9 
764-2 
1 14 
0-968 
Id. 
6 
27-8 
| 26-1 
2 20 
Very heavy rain. 

763-0 
2 45 
0-744 
10 
27-8 1 
26-6 • 
3 0 
0-190 | 
Gloomy ; thunder. 
10 
26-6 
25-Q 1 
3 13 
4 30 
Rain. | 
Heavy rain. 

4 h 2 
