2 E.. Loomis— United States Weather Maps. 
iki. have some connection with the preceding, viz: the 
height of the barometer at the center of the storm; the amount 
of the fall of the barometer in the preceding 24 hours; ; the 
amount of the rise of the barometer in the succeeding 24 hours; 
the change of pressure at the center of the storm in 24 hours, ete. 
he following table shows the average direction and velocity 
of storms for each month of the year, as $ deduced from 814 cases. 
Velocity in Velocity in 
Months, Course of — "ee? Months. Course of miles per 
storm. » storm. hour. 
January, N. 85° E. 28-5 July, N.102° E.| 24-4 
February, N. 76 &E. 31-0 August, i. LTT 
March, N. 179 E 30°8 September, N. 78 E. —22°8 
April, N. 74 KE. 25°6 October, N. 69 BE. 24°4 
May, N.178 E. 24°2 November, N. 80 E. 28°3 
June, N. 93 E. 21:2 December, N. 84 E. 27°6 
| Year, IN.82 E.| 25-6 
The average serie foe of the storm = for two years 
was N. 82° E., or 8° to the north of east, and the average 
velocity was 26 6 railed per hour; but there i is a noticeable vari- 
ation both in the direction and velocity, depending upon the 
season of the year. The course of storms is most southerly in 
summer, and it is a little less northerly in winter than it is in 
spring or autumn. July is the month in which the course is 
most southerly, and October is the month in which it is most 
northerly, the mean difference between these two months 
amounting to 33°. The velocity of progress is greatest in win- 
ter and least in summer. February is the month of greatest 
velocity and August the month of least velocity, the former 
exceeding the latter by 75 per cent. 
The diversity in the direction and velocity of particular 
storms is much greater than this. In one instance, viz: Oct. 
20, 1873, a ee traveled N. 44° W., and in another instance, 
Oct. 25, 1872, a storm traveled about due north. e e 
been ten cases in which the direction of the storm path was 
more than 60° north of east; and there have been three cases 
in which the direction was more than 60° south of east. In 
one case the direction of a storm path was 70° south of east, 
showing the entire range in the direction of storm paths to be 
over 180 degrees. 
The diventy in respect to the velocity of progress of partic- 
r storms is still ter. In some cases, a storm center 
remained sensibly stationary for 24 hours, and occasionally still 
longer, while in four cases a storm center has advanced over 
1,200 miles in 24 hours, and in one case, ey ABs ae, the 
average velocity for 24 hours amounted to 575 hour. 
hve $8 So ee gress ranges from zero os y ‘5 miles 
Pe 
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