e 
Observations of the United States Signal Service. 15 
Stream, where the temperature of the water in January is 
nearly 60°, and the air which flowed in from the north and 
west was excessively cold. It seems probable that this cold 
northwest wind pushed under the warmer wind from the south- 
east as was observed in the storm of March 11, 1874, and that 
this was one cause of the unusual precipitation on the west 
side of the storm-center. This extensive precipitation on the 
west side of the low center is believed to have been the prin- 
d. 
cipal cause of the slow progress of the storm eastwar 
Violent Winds. 
In order to determine the laws which govern the velocity of 
the wind I selected from the published volumes of the Signal 
Service observations (September, 1872, to May, 1874,) all those 
cases in which the velocity of the wind amounted to forty 
miles per hour. The number of these cases was 250, excluding 
_ the observations at Mount Washington and Pike’s Peak, where 
high velocities are very common. Of these 250 cases, eighty- 
two were reported at 7:35 A. M., ninety-one at 4:35 P. M., and 
seventy-seven at ll p.m. These results indicate a slight influ- 
Month.| Cases. | Month.| Cases. | Month.| Cases. 
Jan. 22 | May 5 ||Sept. 
Feb. 12 \lJune 1 |jOct. 6 
March| 21 | July 3 ||Nov. | 23 
April 20 ||Aug. 2 |\Dec. 9 
Thus we see that during the six months, from November to 
most violent winds. 
‘The following table shows the number of cases in which the 
wind blew from each of the eight principal points of the com- 
pass at the time of these high velocities. We see that violent 
winds come from a northern quarter twoand a half times as 
frequently as they do from a southern quarter, and they sel- 
dom come directly from the south. 
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