147 
The mean results for the meteorological quarters, and their 
ratios, are — 
Mean Daily Movement Mean Daily Movement 
of the Wind of the Wind Ratios, 
on Rainy Days. on Fair Days. 
Winter 257 ... 175 ... 0’68 
Spring 252 ... 208 ... 0-82 
Summer 228 ... 166 ... 0*72 
Autumn 267 ... 161 ... 0*60 
From the numbers in the last column it appears that the 
mean velocity of the wind on days when no rain fell, as com- 
pared with that on rainy days, was greatest in spring and 
least in autumn ; and that the relative velocities in winter 
and summer were very nearly equal. It will be interesting 
to ascertain whether this remarkable relation holds good 
through a series of years. 
Arranging the rainy days in four groups, the first contain- 
ing the days on which the rainfall did not exceed 0*2 inch ; 
the second those on which it was above 0*2 inch, but did not 
exceed 0*4 inch ; the third those on which it was above 0*4 
inch, but did not exceed 0*6 inch ; and the fourth those on 
which it exceeded 0 6 inch; and determining for each group 
the mean daily movement of the wind, we have the following 
results : — 
Group. 
No. of Days 
in the 
Daily Rainfall. 
Mean Daily 
Movement 
1 
Group. 
108 
in. in. 
o-o to 0-2 
of the Wind. 
236 
2 
40 
0-2 — 0*4 
270 
3 
17 
0-4 — 0-6 
300 
4 
10 
.. above 0*6 
263 
It appears, therefore, that the maximum mean daily move- 
ment of the wind occurs when the daily rainfall is about 
half an inch, and that during excessive falls of rain the 
velocity of the wind is very sensibly diminished. 
Mr. G. Y. Vernon, F.R.A.S., communicated the following 
“ Note on the Rainfall of the last Twenty-nine Years at 
Roy ton, Oldham,” by John Heap, Esq. 
Seeing in the proceedings of the Manchester Literary and 
