294 
HARRINGTON. 
The completed charts show the stations where for any 
month the wind was twice, thrice, four, or five times as fre¬ 
quent in any direction as would be the case if the winds 
were uniformly distributed. This was taken to indicate the 
most frequent winds and to point out the regions deserving 
more detailed study. Inspection of the maps showed the 
following cases where there was a distinct seasonal change 
in wind direction: 
I. The Texan monsoons, extending up the plains some¬ 
times beyond the limits of Texas and even to the northern 
boundary of the United States. 
II. The California monsoons, occurring on the Pacific coast 
south of San Francisco and reaching up the Sacramento and 
San Joaquin valleys. 
III. The Willamette and Puget sound periodic winds. 
IV. The northeast and southwest winds of the Atlantic 
coast. 
V. The off-coast winds in winter above cape Henry. 
VI. Isolated cases, as Escanaba, Duluth, Las Animas, 
and Winnemucca. 
Aside from these, the direction of greatest frequency of the 
wind is generally westerly over the entire country. In the 
Great Basin the indications are somewhat ambiguous. Over 
the great lakes it is generally west or southwest. Over the 
more northern part of the Rocky Mountain region it is west 
or northwest, while in the southern part (Arizona) it is west¬ 
erly, but there seems to be no decided preponderance of the 
northwest winds over the southwest ones. 
Several of these winds are designated as monsoons. A 
monsoon is, so to speak, an annual land and sea breeze. It 
is a wind that changes its direction twice a year because 
of the differences in temperature of the continental and 
oceanic surfaces over which it flows. In summer the land 
surface is the warmer and deflects the wind toward itself. 
In winter the oceanic surface is the warmer and deflects 
the wind in its direction. It is not necessary that there be 
a complete reversal of direction, though this happens in the 
