1911 - 12 .] 
The Sun as a Fog Producer. 
185 
TABLE No. I. * 
Year. 
Month. 
Day. 
Wind. 
Temperatures. 
Sun- 
shine. 
Limit of 
Visibility 
in Miles. 
Direction. 
Force. 
Night 
Min. 
Dry. 
Wet. 
Diff. 
8 a.m. 
9*30. 
1909 
Feb. 
6 
SW 
•2 
32 
35 
34 
1 
1 
2 
1 
55 
55 
7 
SW 
•2 
i 25 
29 
28 
1 
1 
3 
1 
55 
55 
8 
ssw 
•5 
! 32 
37 
35 2 
D8 
0 
4 
4 
55 
55 
13 
WNW 
•2 
! 28 
33 
32 
1 
1 
10 
10 
15 
55 
16 
SW 
•2 
3D5 
36 
34 
2 
1 
10 
1-3 
55 
55 
19 
SW 
*2 
| 30 
34*2 
33 
1*2 
1 
2 
1 
5 ? 
Apr. 
2 
NE 
•2 
26 
36 
34 
2 
1 
3 
1 
55 
Nov. 
8 
SW 
•5 
i 23 
35 
32-5 
2*5 
| 
10 
1 
55 
55 
21 
wsw 
•2 
30 
37 
36 
1 
i 
100 
2 
55 
55 
22 
WNW 
•2 
27 
35 
31-5 
35 
1 
2 
4 
4 
55 
Dec. 
9 
s 
•1 
31 
40 
38 
2 
6 
10 
10 
1 55 
5 5 
21 
ssw 
•2 
23 
24 
? 
? 
l 
4 
0 25 
1 
55 
55 
27 
SW 
Y 
33 
34*5 
34 
0-5 
1 
2 
5 
0-3 
1910 
Jan. 
4 
wsw 
•2 
38 
38-5 
37*5 
1 
1 
100 
1 
55 
55 
21 
WNW 
•2 
26 
32 
? 
? 
1 
100 
100 
55 
Feb. 
4 
SW 
•2 
325 
35 
33 
2 
1 
3 
1 
55 
55 
15 
ssw 
*2 
33 
36 
34-8 
1-2 j 
1 
T) 
3 
1-3 
55 
Mar. 
29 
SW 
1- 
27‘5 
37 
35-3 
F7 j 
1 
5 
0-25 
55 
Nov. 
20 
w 
•2 
24 
36 
32 
4 
1 
100 
100 
1911 
Jan. 
12 
NNW 
*2 
32*8 
34 
32 
2 
1 
10 
10 
1912 
Feb. 
20 
WNW 
•2 
38-8 
41 
39 
2 | 
1 
100 
100 
dense haze or fog ; or to its blowing from a pure direction. In many of the 
observations not here recorded the increase in haze was slight, but it was 
observed that on all the mornings the increase was directly proportional to 
the humidity and sunshine, and inversely to the velocity of the wind and 
dryness of the air, and that when the wind was from an impure direction 
the thickening invariably took place when the conditions were favourable. 
With north-westerly winds, however, this thickening did not take place 
unless the velocity of the wind fell to nearly calm, in which case, the 
impurities thrown into the air in the immediate neighbourhood not being 
carried away, a thickening took place. If the velocity of the wind was 1 
or over on the usual scale, little thickening took place even when the wind 
was from an impure direction ; but even with a force of 1, considerable 
thickening took place if the air was very damp. Clear sun at sunrise gave 
the maximum effect, but sunlight through clouds also acted on the air, 
though much less powerfully. The humidity and the sunshine are the 
* In the above table it will be noticed that in all but one case the force of the wind was 
less than 1 on the usual scale (1-12), that is, there was generally only a gentle drift. In 
the column under “ Sunshine ” 1 indicates a cloudless sky, that is, continuous sunshine. 
