Aggregated and Specific Courses of Winds. 329 
hurricane moving in this direction, with a progress of 500 to 
1000 miles per day, overlaid and accompanied by a regular 
southwest current ; and yet, if we should attempt to resolve the 
aggregate course and progression of this storm solely by a general 
mean of its observed winds, at the earth’s surface, we might be 
led to very erroneous conclusions. For these rotary winds, instead 
of showing the true progression of the storm, might appear nearly 
to balance each other. Moreover, the winds of this storm, when 
considered locally, are found to exhibit nearly the same phases or 
Succession of changes which are common to the temperate lati- 
tudes of the north Atlantic basin; which serves to show that our 
successively observed winds are commonly of a rotary character, 
and that the common method of estimatmg the mean resultant 
courses or progression of the surface winds is necessarily defec- 
tive and cannot show the true progression of the lower at- 
_ mosphere. : 
- Some writers have described our northerly winds as sweeping 
from Canada to the Gulf of Mexico and Cuba, and thus re- 
ducing the temperature of the latter regions. ‘But it is evident 
that these persons have mistaken the cold winds which are found 
on the western side of our revolving storms, as being a direct 
cutrent from the higher to the lower latitudes. I cannot find 
that the above geographical course has ever been pursued by the 
Winds of this continent. On the contrary, in times of the greatest 
ression of the thermometer, in numerous instances, the cold 
Period has been found to have first taken effect in or near the 
tropical latitudes and Gulf of Mexico; and has thence been prop- 
agated towards the eastern portions of the United States, ina 
manner corresponding to the observed progression of the storms. 
- The only proper current of surface winds found coursing to- 
wards the equator, in the temperate latitudes of North America, 
exists on the western side of the continent. But a high current 
from the northwest, which may have crossed the Rocky Moun- 
tains in its course, appears at successive and alternate periods, of 
Considerable duration, in the higher region of clouds. Its direc- 
tion nearly coincides with the closing winds of our revolving 
Storms, and in the winter season, in some cases, it probably sub- 
Sides to the surface and immediately follows these storms, for two 
r three days, and sometimes longer. This will accord with 
news which have been expressed by the sg President Dwight 
me Szcoxp Series, Vol. Il, No. 6.—Nov., 1846. 
