THE LAW OF STORMS DEVELOPED. 391 



on our Western plains as the laboring wheel of the steamship buried in 

 a heavy sea, all attest that a body cannot move on the earth's surface 

 in a straight line. It is not more true with us that the Gulf Stream 

 turns to the eastward, the Polar Stream to the westward, and the equa- 

 torial currents to the northward, than that every air-current, in obedi- 

 ence to the same law, should turn to the right of the line along which 

 from any cause it is called to move. The meteorist has therefore only 

 to ascertain by observation where the barometer is lowest, to know at 

 once the direction of the winds from the circumjacent districts, far 

 and near, or at least to test the mathematical law by a grand experi- 

 ment. 



The tangential and centripetal forces, acting at the same time on 

 any particle of air in the storm, may be equal or very unequal, and the 

 cyclonic character of the gale may be well marked or partly concealed. 

 In the tornado, with a diameter of only a few hundred feet, the tan- 

 gential force may not be appreciable to an observer, but it is present, 

 and intensely assists in communicating vorticose motion to the storm, 

 whose roar is heard with awe by the stoutest heart, as it crashes 

 through the forest and even ploughs up the soil of the earth. If the 

 cyclonic or spiral feature should fail to manifest itself in any storm, we 

 ought to look for such failure in the tornado. It is true that no bar- 

 ometric readings have ever been taken in the narrow heart of a tor- 

 nado, but abundant evidence exists of the fearful rarefaction in the 

 centre. While the meteor, once set in motion, may move forward 

 with great velocity and destructiveness, the danger is clearly due to 

 the intro-rushing and gyratory winds. There is not an instance, it is 

 believed, recorded in which a tornado moved as much as 100 miles an 

 hour; probably one-half that velocity would be too high an estimate 

 for its usual and ordinary motion. But the wind, moving straightfor- 

 ward at the rate of 60 or 80 miles an hour, never worked any thing 

 like the disaster of a tornado. In the West-Indian hurricane, blowing 

 at the rate of 100 miles an hour, houses have been blown down, ships 

 inumerable stranded ; but all this is mere child's-play compared to the 

 suction and whirl of the tornado. The conclusion forced upon us is, 

 that the ravages of the latter are due, not to the weight of the atmo- 

 sphere, moving as a river-torrent in a straight line, nor to the rush of 

 air behind the travelling vacuum, but to the torsive, racking motion 

 imparted to every object in its path due to its gyration. To prove 

 that this gyration is always from right to left, or against the hands of 

 a watch, is, of course, practically impossible ; but such a direction has 

 often been observed in tornadoes. 



It may, therefore, be safely concluded that, for all processes of me- 

 teorologic calculation, the disiurbance, if not such at first, will soon 

 become cyclonic. All daily weather-charts demonstrate this, not by a 

 laboratory or lecture-room experiment, but on an infinitely wider and 

 grander scale, and in a manner far more conclusive than any merely 



