418 
Proceedings of Boyal Society of Edinburgh. [july 18, 
in mean monthly temperature, of 24° *3, its temperature in February, 
for which month it is the coldest wind, being 19° *7 ; and in July, 
when it is not only the warmest for that month, but also for the 
whole year, its temperature is 44° - 0. The wind having the least 
annual range is the north-west, its temperature in January being 
24° T, and in August 35° ‘8, thus giving it a range of 14°*4. The 
mean annual range for the directions S.W., W., N.W., is 15° *6., 
and that for S.E., E., N.E., is 20°*7. The difference between these 
ranges is apparently due to the fact that the easterly winds blow 
over land, and the westerly winds over sea, — land areas being 
subject to greater extremes of temperature than sea areas, and this 
is apparently the cause of the oscillation above referred to. In the 
tables given with Mr Omond’s paper on “ Winds and Rainfall ” in this 
number of the Journal,* it is seen that the greater number of south- 
east winds belong to anticyclonic systems, and this also may have 
a good deal to do with the great annual range of temperature of the 
south-east wind. A comparison of the temperatures of the same 
direction of wind in cyclonic and anticyclonic systems has not as 
yet been made ; but I could see, when working up this table, that 
such a comparison would probably result in interesting and useful 
knowledge. It may be noted that each of the directions, S., S.W., 
Thermal Windrose, Ben Nevis Observatory. ( Computed from the 
Observations of the three Years, June 1884 to May 1887.) 
N. 
N.E. 
E. 
S.E. 
S. 
S.W. 
W. 
N.W. 
Calm or 
Vari- 
able. 
Mean of 
Month. 
Mean of 
8 Winds 
January 
20-6 
18-7 
18-8 
20-5 
23-3 
25-3 
24-2 
24-1 
22-1 
22-9 
2D9 
February 
21-5 
21-5 
21-9 
19-7 
24-3 
27-8 
27-4 
24-8 
21-1 
24-0 
23-6 
March 
19-9 
18-2 
19-5 
197 
28-9 
28-3 
27-9 
26-5 
23-1 
22-8 
23-2 
April 
24-3 
24-1 
24-4 
27-8 
27-9 
28-3 
271 
26-0 
26-2 
26-5 
26-5 
May 
27-9 
27-4 
29-5 
31-4 
3D5 
31-8 
30-0 
29-0 
29-9 
29-9 
29-8 
June 
35-5 
33-6 
33-5 
37-5 
38-1 
37-3 
36-5 
35-8 
36-7 
36-2 
36-0 
July 
37-3 
33-9 
38 9 
44-0 
42-8 
411 
40-1 
38-0 
38-5 
40-6 
39-5 
August 
36-2 
35-8 
36 2 
40-7 
42-5 
41-8 
39-5 
38-5 
37-9 
40-7 
38-9 
September 
31-9 
31-1 
34'4 
40-5 
39-5 
37-8 
36-7 
34-7 
34-1 
36-9 
35-8 
October 
29-9 
28-6 
29-0 
31-4 
33-8 
32-7 
31-8 
31-1 
30-6 
31-2 
31-0 
November 
25-2 
25-4 
26-3 
26-6 
30-2 
' 31-3 
30-2 
29-5 
25-8 
28-2 
28-1 
December 
21-4 
19-5 
21-1 
22-9 
27-9 
27-0 
25-8 
25-8 
23-5 
23-4 
23-9 
Year 
27-6 
26-5 
27-8 
30-2 
32-6 
32-5 
31-4 
30-2 
291 
30-3 
29-8 
Spring 
23-7 
23-2 
24-5 
26-3 
30-0 
29-5 
28-3 
27-2 
26-4 
26-4 
26-5 
Summer 
36-3 
34-4 
36-2 
40-7 
41-1 
40-1 
38-7 
37-4 
37-7 
39-2 
38-1 
Autumn 
29-0 
28-4 
29-9 
32-8 
34-5 
33-9 
32-9 
31-8 
30-2 
32-1 
31-6 
Winter 
21-2 
19-9 
20-6 
21-0 
25-2 
26-7 
25-6 
24-9 
22-2 
23-4 
23-1 
* See Journal of Scottish Meteorological Society , vol. vii. p. 275, and vol. 
viii. p. 18. 
