^282 Caleb Atwatcr on the Winds of the fVesL 



From several gentlemen, residents for many years in Illinois 

 and Missouri Territories, 1 have been informed, that changes 

 of weather in that region of country are, especially in winter, 

 very frequent and great ; that oc£ day the moist south wind 

 from the Mexican gulf will prevail, and produce quite warm 

 and mild weather for the season ; on the very next, or fre- 

 quently in the latter part of the same, the current of air from 

 the sources of the Missouri will prevail, and block up the 

 streams with ice. 



There is a third current of air which prevails during our 

 winter months, more and more, annually, as the country be- 

 comes cleared of its forests in the direction alluded to ; it pro- 

 ceeds from the great lakes to the northwest of us, and even be- 

 yond them. Proceeding as it does; from the north and north- 

 west of lake Superior, and crossing the great expanse of water 

 in this direction, it rushes down these great lakes to the south 

 end of lake Michigan in latitude about 41® north, diverges from 

 that point, and spreads over the immense regions lying to the 

 south, where the air is more rarefied by reason of its warmer 

 climate. This current of air brings along with it intense cold, 

 and extended last winter even to New-Orleans, where the snow 

 fell to such a depth, that sleighs were seen passing in every 

 part of the city. The more the forests are cleared away be- 

 tween any place in this country and the northern lakes, the more 

 this cold current of air will prevail. This current also diverges 

 from the southern shore of Lake Erie, but is not so strong as 

 that part of it which diverges from the south end of Michigan, 

 and of course does not extend as far to the south. When this 

 part of this state was first settled, this current of air was hardly 

 felt at this place, and then only for a short time in the winter 

 months, and hardly ever reached the Ohio river ; but last win- 

 ter it continued three weeks at one time, and produced good 

 sleighing ; and also caused rheumatisms, pleurisies, peripneu- 

 monies, &c. which proved mortal to some. In this place, 

 which is in latitude about 39** 20' north, the thermometer of 

 Fahrenheit, hanging in an entry of a dwelling-house with closed 

 doors, sunlt to 24 degrees below zero. This extreme cold mav 



