44 Origin, Extension and Continuance of Prairies. 



A TOENADO. 



We have stated that hurricanes and whirlwinds, by their inroads 

 upon the forests, are chiefly instrumental in forming prairies. 



It is believed that hurricanes are not so frequent and so violent as 

 formerly. For the last twenty-five years particularly, they have dimin- 

 ished in number and energy. The signs of hurricanes, -previous to 

 the year 1805, would indicate in their case, a frequency and violence 

 unequalled in any subsequent period. 



In the year 1805 it happened to the writer to be roving on that 

 most beautiful lawn, extending from Kaskaskia to Illinois, and which 

 is called the American bottom. There was the most charming alter- 

 nation of prairie, and woodland, and while he was musing on the 

 causes which gave rise to forests of grass, or cane, and of stu- 

 pendous oaks and cotton woods, he was roused, and his attention di- 

 rected to a scene of unequalled grandeur and horror. It was a whirl- 

 wind that had crossed the Mississippi, and was making its way through 

 the swamp, until it was near the charming prairie, which at that mo- 

 ment afforded rest and comfort to a solitary pedestrian. By the irre- 

 sistible force of the wind, whole forests were in a moment twisted 

 from the ground, and when thrown from the mouth of the vortex, 

 such was the violent collision of tree against tree, that they were 

 pounded into billets and splinters. A sound of universal distress burst 

 forth from every quarter, and earth and sky appeared to be blended. 

 In a twinkling the tornado scooped up a lake, with two or three feet 

 of mud which lined its bottom. In one instant more, it tore away 

 a house with its stone chimney. In another moment thirty or forty 

 horned cattle, and fifteen or sixteen horses, disappeared with incon- 

 ceivable quickness. The whirlwind twisted off almost every spear 

 of a wheat field, and bore it away \v\ih the fence, cattle, horses, lake, 

 trees, house, and whatever was in the way. For more than a mile 

 the heavens were black, and filled with the wreck of the tempest. 



In this tornado, as well as many that had before occurred in these 

 countries on a smaller scale, there was nothing to justify a belief with 

 Mr. Dunbar, " of a vortex with a central spot in a state of profound 

 calm ;" or of Dr. Franklin, who supposed the " vortex of a whirl- 

 wind to be a true vacuum." 



From the- lake to the house, was about two hundred yards, between 

 which stood a huge cotton-wood tree of at least seven feet in diame- 

 ter, and more than one hundred feet in height. It was observed, 

 when the vortex had nearly or quite reached the tree, that the leaves 



