E. Loomis—- United States Weather Maps. 9 
Relation between the velocity of the wind and the velocity of a 
storm’s progress. 
In order to determine the relation between the velocity of a 
storm’s progress and the velocity of the wind in the different 
quadrants, it is important to know not simply the wind’s veloc- 
ity at the surface of the earth, but its velocity near the central 
region of the storm, which is presumed to be at an elevation of 
at least one or two miles. In order to form some estimate of this 
velocity, I took the observations at the signal service stations 
for Sept., 1872, which have been published complete in a sep- 
arate volume, and determined the average velocity of the wind 
on the summit of Mount Washington, and also the average at 
the three nearest stations near the level of the sea. These sta- 
tions were Burlington, Vt., Montreal, Can., and Portland, Me. 
The average velocity of the wind on Mount Washington was 29 
miles per hour; the average at the three other stations was 53 
miles ; hence we conclude that the ratio of the wind’s velocity 
near the level of the sea to its velocity on the summit of Mount 
Washington is as one to 55. Now the average velocity of the 
wind at stations on the earth’s surface, for the different quad- 
rants of the storm, has been found to be 10-1, 8°8, 8°3, an 
76 miles per hour; hence the velocity at the height of 6,000 
feet may be estimated to be 555, 48-4, 45°6, and 41°8 miles. 
e wish now to determine the average direction of the wind 
in the different quadrants. For this purpose, each weather 
ed a storm center was crossed by two diagonal 
S noseme Then, beginning with the west quadrant, T counted 
the number of stations at which the wind was reported from the 
north; also the number from the northwest, west, southwest, 
etc.; and in like manner for each of the four quadrants. The 
same was done with each of the weather maps, which furnished 
an example suited to this comparison. In determining the 
limits of each storm, the same rule was adopted as has been 
already stated in determining the velocities of the winds. I 
wind. The following table shows the resulting directions and 
also the velocities, as already stated, for an elevation of 6,000 feet. 
W.quadrant.  8.quadrant. E.quadrant. N. . 
Veloci ind, 5 48-4 45°6 | 
Direction pile N. 58° 48” W. 8. 40° 257W. 832° 6/E, N. 42°33’ E. 
In order to exhibit palpably to the eye the significance of 
these results, I have constructed the following igure, in 
which the four arrows show the average direction of the 
wind in the several quadrants, and the lengths of the arrows 
