Caleb Atwater on the Winds of the West. 981 
within my reach might be multiplied to a much greater extent, 
but they are probably unnecessary. 
But another current of air prevails here, especially in the cold 
months, coming from the mouth of the Missouri, which is a little 
to the south of west of this place. This current is colder than 
the preceding one, and though moist, yet not as much so as the 
one already described. It prevails generally in October and No- 
vember, before our warm weather is over, and produces frosts 
and a chilly dampness, and what I have observed nowhere else, 
especially on the east side of the Alleghanies, it produces a kind 
of faintness at the breast. : 
People of delicate habits, coming here from the northern and 
eastern states, uniformly complain of this faintness. It is not 
perhaps extraordinary that this current of air should be cold, 
proceeding as it does froma high northern latitude, along the 
great chain of rocky mountains in the northwest; that it should 
be moist, and perhaps also that it should affect the animal econ- 
omy unpleasantly, may possibly be atiributed to its passing such 
a length of way over the waters of the Missouri, and the wet 
prairies and barrens lying so extensively between us and the 
head waters of that stream. ‘The luxuriant vegetation which 
covers these prairies and barrens at that season of the year, be- 
gins to putrefy, and fills with unhealthy exhalations every gale of 
Wind which passes over them. ugg 
At the mouth of this river (Missouri,) which is in about lati- 
tudé 38° north, this current of air is extremely cold in the win- 
ter months. It diverges from this point, and produces extreme 
- old at a considerable distance to the south of it on the Missis- 
sippi river. Gen. Rector, the present surveyor general of the 
United States, who keeps his office at St. Louis, informs me, that 
¢ has known the Mississippi at St. Genevieve, in latitude about 
37°, so firmly covered with ice in one night, as to be able to 
bear horses and cattle the ensning day. This circumstance must 
have been owing to the sudden change of the current of air from 
South to the northwest, descending the Missouri river from. the 
Cold regions at its sources. ; 
Vou. 1....No. 3. 10 
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