Velocity of the Wind. 
101 
Date. 
Ships’s 
notion in 
uiles per 
Angle of the 
wind to the 
ship’s 
Force of 
wind on a 
sq. foot in 
lbs. aver. 
Tabular ve- 
locity cor- 
responding 
Revolu- 
tions of 
mill 
anernr. 
Relative 
velocity 
of wind 
felt by 
the ship. 
Actual 
v elocity 
of wind 
indepen- 
hour. 
course. 
corrected for ship’s 
course. 
per mi- 
nute. 
dent of 
ship. 
Aug.2i 
by log. 
9.0 
95.° 
0.85 
mif&s p. hr. 
14.0 
1080 
miles. 
7.4 
miles. 
7.0 
21 
9.4 
100 
0.90 
14.2 
1170 
8.1 
7.5 
23 
10.0 
80 
1.62 
18.0 
1515 
10.3 
12.5 
24 
8.6 
105 
— 

1636 
11.2 
8.0 
25 
9.0 
125 
1.20 
16.0 
1660 
11.4 
6.0 
2b 
9.0 
105 
0.85 
14.0 
1173 
8.1 
6.0 
31 
6.0? 
so 
0.17 
5.4 
459 
3.8 
3.8 
Sep. 2 
4.0? 
only felt in 
lee roll 90°. 
— 
110 
2.0 
2.0 
5 
5.0 
80 
0.30 
7.6 
325 
3.1 
4.0 
t 
5.4 
60 
— 
— 
505 
4.1 
6.8 
8 
7.2 
60 
0.41 
9.0 
614 
4.7 
8.0 
C 
8.2 
50 
0.48 
10.0 
680 
5.1 
10.5 
The last column but one in this table is that upon which the chief confidence is to 
be placed ; and if it be indeed allowed to warrant any conclusions, we may infer from 
it, that a ship sails with the least relative force of wind, when the latter is on the 
beam or the quarter ; that with moderate breezes a-bearn, the ship will move through 
the water faster than the wind which impels her; that even with a strong breeze of 
10 knots a-beam, the ship will keep pace with the wind ; with the wind before the 
beam, the experiments arc at variance, but on an average the motion of the ship was 
even then equal to that of the absolute current of air, if not greater. 
It may be remarked, that in theory there is nothing anomalous in these results, 
for supposing the directions of the wind and the ship to be at right angles with one 
another, and“ assuming that both were of an unyielding nature, the motion of the 
ship would depend upon the angle which the sails made with the wind, being as 
tangent of this angle, while the wind’s velocity is radius ; and consequently, theoreti- 
cally speaking, it might increase art iiflnitHin*. This, however, is very far from the 
real state of things in nature, and nothing but experiment can determine the variable 
influence of the wind and the water upon different forms of vessels, and under every 
different circumstance of position, form of sails, trim, tonnage, &c. I he ship allud- 
ed to in the present notice was a good sailer, and earned hut little freight when the 
experiments were made. Her greatest rate was 10* knots with the wind on the 
quarter, and the velocity of the latter Ay the tubular rates vf the force was 2., knots. 
In the strongest period of a gale near the Cape, the same instrument gave the vclo- 
city of the wind between 30 and 40 miles an hour, the force measuied being 6 and 
7 lbs. on the square foot ; but from the subsequent comparisons with the two instru- 
ments, it becomes doubtful whether the velocity exceeded ill) miles at the utmost. 
I have said quite sufficient to show how much uncertainty still dwells on all these 
Points and I conclude by inviting nautical men to give some aid to their elucidation. 
From the hints I have given, any maker of mathematical instruments can construct 
a windmill anemometeri-the simple wheel work onVollaston s trocloameter would 
answer the purpose perfectly, the register of revolutions for 10 inmates or so, 
might he kept with the log daily; and any experimentalist at home jS in India could 
prepare a just table of the value of the revolutions in rectilinear motion. 
* The extremities of the vanes 
over a much greater space in a given 
motion. 
of a windmill, for instance, generally run 
time than the current of air which gives them 
