56 On the Winds of the Western Coast of the U. States. 
es with that of the other spaces. All show the same defi 
ciency of easterly winds, and San Francisco is deficient also in 
southerly ones. 
The monthly curves grouped in two periods, from November — 
to March, both included, and from April to October (figs. Nos. 
14 and 15) show that the annual curve has the summer type im- 
pressed upon it. The summer is in fact the windy part of the 
ear. The N.W. wind prevails in August at Astoria and San 
iego, and the W. and 8.W. at San Francisco. 
The scale of diagram No. 14 is less than that of 15 in the 
roportion of 10 to 14. There is scarcely any wind from points — 
fiatirecs North, around by East and South. The form of the 
rose is exceedingly simple and the generalization very obvious. — 
The winter system is less simple. The axes of the spaces for 
Astoria and San Diego make angles of more than 110° with each 
other. The N.E., E.,S., and S.W. winds are considerable at 
Astoria, and the N.W. wind is deficient. At San Francisco the 
W. winds give the prominent feature to the rose curve. ee 
As the winter is not the windy season, so the months of March 
and September are not the windy months. On the contrary, 
July is one of the windiest months of the year. oy 
SAN FRANCISCO. 
At San Francisco the great current of air flowing from the 
sea to the land comes generally from the W. or 8.W., rarely 
from the N.W. 
In the period from November to March inclusive, (diagram 
No. 14,) the W. is the prevailing wind, exceeding in ques 
both the others, the S.W. wind exceeding in quantity the N.W-— 
In oo from April to October (diagram No. 15) the W- 
and 8.W. winds are nearly equal, and each exceeds the N.W- 
The W. wind has in general the features attributed to the se 
breeze, beginning after the rising of the sun, increasing unt! — 
after the cic on ai of the day, and dying out or much dimm — 
ishing at nigh : 
The W. and S.W. winds give the prominent features to the a 
cisco 
ceeded by an easterly land breeze—but rising and falling. The 
rose curves for May and August resemble each other, the N.W. | 
