EF, Loomis— Observations of the U. S. Signal Service. 19 
seems to warrant the following conclusions: 1. High winds on 
Mount Washington circulate about a low center as they do 
near the level of the sea. 2. The motion of the wind is 
nearly at right angles to the direction of the low center. 38. 
The low center at the height of Mount Washington sometimes 
lags behind the low center at the surface of the earth appar- 
ently as much as two hundred miles. 
High Winds on Pike's Peak. 
In order to study the laws of the winds on Pike’s Peak, I 
selected from the published volumes of the Signal Service | 
observations (November, 1873 to January, 1875) all those cases 
in which the velocity of the wind was as great as thirty miles 
per hour. The number of these cases was 363, of which 136 
were reported at 7.35 A. M., 97 at 4.35 P. M., and 130 at 11 P.M. 
Hence it appears that at 4.35 Pp. M. high winds are twenty-five 
per cent less frequent than at the other two hours of observa- 
tion. But near the level of the sea the average force of the 
wind at 4 p. M. is double that at the other two hours, which 
results accord with the Mt. Washington observations in indicat- 
ing that these high winds are mainly independent of the causes 
which determine the diurnal change at the level of the sea. 
The average number of cases of violent winds for each 
month of the year is as follows: 
Spring. Summe Autumn, Winter. 
March 14 June 21 Sept. 17 Dec. 28.5 
April 17 $15.7 July 2}>11.3 Oct. 24} 26.5 Jan. 42}31.2 
May 16 Aug. 11 Nov. 38.5 Feb. 23 
Thus we see that during the winter months high winds are 
nearly three times as frequent as during the summer months. 
The following table shows the number of cases in which the 
wind blew from the different directions at the time of these 
high velocities. 
North, 28 cases. South, 18 cases. 
Northwest, 47 * Southeast, 1 case. 
W ¥y 54 “ “ 
Southwest, lll ‘ Northeast, 4 cases. 
Thus we see that seventy-three per cent of these high winds 
come from the west and southwest, and only one per cent comes 
from any easterly poi 
In order to determine whether these high winds bear a con- 
stant relation to centers of low pressure near the level of the 
sea, I have prepared a table similar to that on page 16. For 
the west winds I have employed all velocities amounting to 
fifty-tive miles per hour; for the southwest winds I have 
employed velocities of fifty miles per hour; for the northwest 
winds velocities of forty-two miles per hour; for the north 
winds thirty-five miles per hour; for the south winds thirty- 
