748 THE POPULAR SCIENCE MONTHLY. 



ency to fatten, and animals intended for the shambles have been pur- 

 posely rotted in order to increase their fattening properties. A cele- 

 brated stock-man in England used to overflow his pastures, and, after 

 the water was run off, turn on his sheep which he was preparing for 

 the market. These animals became infested, accumulated flesh rapidly, 

 and by this manoeuvre a gain of some weeks was obtained. The prac- 

 tice is certainly questionable, if not positively vicious. 



The writer claims no originality in the present paper, and only acts 

 the part and that imperfectly of a middle-man in science. 



CYCLONES AND TORNADOES. 



By GEOEGE CLINTON SMITH. 

 CYCLONES. 



TOWARD the western portion of the United States, along the 

 twenty-fifth parallel of longitude, lies a vast tract of sandy, arid 

 country, known to the earlier geographers as " The Great American 

 Desert." It is true, the limits of this great area have become circum- 

 scribed by the onward march of civilization, but the sandy waste is 

 still there, and must ever remain. Still farther westward, the Rocky 

 Mountains rear their lofty, snow-crowned heads in one continuous 

 chain, three thousand miles in length. Rich in mineral wealth, the 

 delight of tourists, and the home of a prosperous people, these moun- 

 tains have a different and equally valuable office to perform in the 

 exercise of an important influence upon the climate of our continent. 

 Were they to be removed, the entire territory west of the Mississippi 

 River would soon become an arid, lifeless desert. 



All storms, of any magnitude, that visit the United States, except 

 the tropical hurricanes which sometimes touch the southern coasts, 

 have a common origin in or near the Rocky Mountains. Here the 

 first barometric depression is felt, preceded by a rising temperature, 

 caused by the warm winds moving northward over the sun-heated 

 sands of Arizona, New Mexico, and Western Texas. These warm, 

 rarefied currents of air are met by cooler currents passing over the 

 snow-clad peaks of the north ; a cyclonic storm is formed, usually 

 small at first, which begins its journey eastward, gradually developing 

 in energy and area as it goes. After leaving the mountain-ranges, 

 there is but little precipitation for the first few hundred miles ; as it 

 advances, it usually widens from north to south, but the line of travel 

 of the storm-center can be readily predicted by the Signal-Service 

 observers, and its location at any time fixed by the lowest reported 

 reading of the barometer. 



During the journey of the storm eastward or southeastward, the 



