194 
“ On a Diurnal Inequality in the Direction and Velocity 
of the Wind, apparently connected with the daily changes of 
Magnetic Declination,” by Joseph Baxendell, F.R.A.S. 
In a Paper with the above title read before the Section 
on the 5th January, 1867, I gave the results of a discussion 
of the Anemograph observations made at the Radcliffe obser- 
vatory, Oxford, during the eight years 1859 — 66, and showed 
that the differences between the bi-hourly directions and 
velocities of the wind indicated the operation of a force 
acting in a direction from magnetic west to east during the 
hours of from about 7 a.m. to 9 p.m., and producing its 
maximum effect from 1 to 2 p.m. The Anemograph results 
for 1867, have since been published in the volume of 
“Radcliffe Observations” for that year; and a copy of the 
unpublished results for 1868, having been kindly forwarded 
to me by the Rev. R. Main, F.R.S., the Radcliffe Observer, I 
have combined the results of these two years with those of 
the previous eight years, and thus obtained the following 
mean results for the entire period of ten years, 1859-68 : — 
h 
Mean 
Direction. 
O 1 
Mean 
Bi-horary 
Velocity. 
h 
Mean 
Direction. 
o / 
Mean 
Bi-liorary 
Velocity. 
0 
222 
30 
15-88 
12 
214 
14 
12-38 
2 
223 
33 
1602 
14 
214 
32 
12-27 
4 
221 
37 
15-00 
16 
214 
47 
12-28 
6 
218 
23 
13-53 
18 
216 
28 
12-26 
8 
214 
36 
12-78 
20 
217 
9 
1301 
10 
213 
32 
12-58 
22 
219 
54 
14-62 
These results, like those for the eight years, 1859-66, 
show that during the night little or no change takes place 
in the direction and velocity of the wind; about 7 a.m. both 
the angle of direction and the velocity begin to increase, 
and attaining their maxima a little before 2 p.m. they 
afterwards gradually diminish until about 9 p.m., when 
they again resume their night values. 
The rectangular co-ordinates A aud B of these directions 
and velocities, taken in the direction of the meridian, and 
at right angles to it, and the differences between the indi- 
