98 
the hours lh., 3h., 5h., &c. It is evident, therefore, that the 
velocities in Table III. do not strictly correspond to the 
hours and directions opposite to which they are placed; 
but, although the errors which would arise from this cause 
might not materially affect the ultimate results, I have 
thought it desirable to reduce the velocities to the times for 
which the directions are given. This I have done by simply 
taking for each hour the mean of the velocities for the two 
preceding and two following hours. The corrected results 
are given in Table IV. 
Table IV. 
h. 
Mean 
Direction. 
... 227 41 ... 
Mean 
Bi-horary 
Velocity. 
h. 
Mean 
Direction. 
... 221 43 ... 
Mean 
Bi-horary 
Velocity. 
0 ... 
... 15*18 
12 ... 
... 11-79 
2 ... 
... 229 46 ... 
... 15*47 
14 ... 
... 222 29 ... 
... 11*71 
4 ... 
... 227 52 ... 
... 14*59 
16 ... 
... 221 57 ... 
... 11*56 
6 ... 
... 226 0 ... 
... 12*95 
18 ... 
... 224 10 .. 
... 11*60 
8 ... 
... 221 33 ... 
... 12*05 
20 ... 
... 224 5 .. 
... 12*48 
10 ... 
... 220 27 ... 
... 11*88 
22 ... 
... 227 43 .. 
... 14*05 
On looking over the numbers in this table it will be seen 
that from about 9h. to 19h., or from 9 p.m. to 7a.m., the velocity 
of the wind is nearly constant; it afterwards rapidly 
increases, attains a maximum a little before two o’clock, and 
then returns rapidly to the night’s rate. The variations in 
the direction of the wind also follow those of the velocity 
pretty closely. The total movement of the air between 
9 p.m. and 7 a.m. is 58*52 miles in a mean direction from 
S. 42° 8' W. ; and between 7 a.m. and 9 p.m. the total move- 
ment is 96*67 miles from S. 46° 36' W. It appears, therefore* 
that at about 7 a.m. a force which has been almost, if not 
quite, inoperative during the previous ten hours begins to 
act on the wind from a westerfy direction, and gradually, 
but rapidly, increasing in intensity, produces its maximum 
effect between 1 and 2 p.m ; it then gradually diminishes, 
and finally ceases to act about 9 p.m. The intensity of this 
force as measured by the changes which it produces in the 
direction and velocity of the wind is at its mean value 
