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March 17, 1871.] 65 [Chase. 
WINDs OF THE United States. 
By Puiny EARLE CHASE. 
(Read before the American Philosophical Society, March 17, 1871.) 
Notwithstanding Ferrel’s mathematical, and Galton’s practical, demon- 
stration of the tendency, in winds of propulsion, to become anti-cyclonic, 
many meteorologists regard cyclonic atmospheric currents as normal, in 
fair as well as in stormy weather. Such an impression may be naturally 
strengthened by the admitted facts, that most of the European winds are 
cyclonic, that all currents flowing in towards a centre of low pressure, 
speedily become cyclonic, and that the system of aspiration induced by the 
diminished pressure at the equator, is the proximate cause of all our at- 
mospheric circulation. 
But it should be remembered on the other hand, that the normal mo- 
tion of the principal oceanic, atmospheric and magnetic currents, both 
polar and equatorial, and the daily veering of the wind consequent onthe 
progressive heating of the earth’s surface, are confessedly anti-cyclonic; 
that centres of violent and rapid commotion must necessarily cover a 
smaller area than the less disturbed peripheries which help to restore the 
equilibrium; that the air drifts more often in alternate ridges and troughs 
than in spirals; and that downward pressure is the impelling force by 
which the partial vacua, produced by increase of temperature or by con- 
densation of vapor, are supplied. Each of these considerations is indicative 
of systems of winds over the entire globe, which are normally anti-cyclo- 
nic, and only exceptionally cyclonic. Even in storms, the blending of 
opposite currents may take place at a circumference as well as at a centre, 
and condensation of vapor may be going on along an extended line, the 
equilibrium being restored by the pressure of an adjacent ridge, as well 
asover a limited area towards which there is an influx from all quarters. 
There may, therefore, be anti-cyclonic as well as cyclonic storms. In fact, 
as I stated at the last meeting of the Society, most of our recent storms 
have been of the former character, and the more closely I have serutinized 
the Signal Service observations, the more strongly have I been impressed 
with the belief that most, if not all, of our north-easterly storms are anti- 
cyclonic as a whole, though they may be accompanied by limited and 
comparatively insignificant local cyclones, and although, in consequence 
of the trend of our Atlantic coast and the in-draught towards the gulf 
stream, they may assume a form more or less cyclonic as they leave our 
shores. 
The charts in Coffin’s Winds of the Northern Hemisphere, seem to me 
to furnish ample confirmation to these views, although, in consequence 
of their very admirable fulness of detail, general tendencies are some- 
times disguised by the local deflecting influences of mountains, lakes and 
valleys. In order to eliminate such local disturbances, I have grouped 
by States and Territories, all the winds in the first volume of the ‘‘Re- 
sults of Meteorological Observations,’’ from 1854 to 1859 inclusive, and 
computed the resultant for the entire period for each district. 
Kers 8.—VOn. STL 
