On the prevaling Storms of the Atlantic Coast. 45 



current in the same manner, to a less extent, owing to the centrifu- 

 gal action of the storm; the greatest velocity and force being un- 

 questionably produced at a considerable elevation. These lateral 

 effects or overlayings in the higher portions of the atmosphere often 

 occur, it is believed, without .producing any visible influence at the 

 surface. A somewhat contrary effect is usually produced on the re- 

 ceding margin where the prevailing current, or impelling wind, presses 

 heavily upon the advancing mass, and generally overlays it to some 

 extent. 



One of the most important deductions which may be drawn from 

 the facts and explications which are now submitted, is an explana- 

 tion of the causes which produce a fall in the barometer on the ap- 

 proach of a storm. This effect we ascribe to the centrifugal ten- 

 dency, or action, which pertains to all revolving or rotatory move- 

 ments, and which must operate with great energy and effect upon 

 so extensive a mass of atmosphere as that which constitutes a storm. 

 Let a cylindrical vessel of any considerable magnitude, be partially 

 filled with water, and let the rotative motion be communicated to 

 the fluid, by passing a rod repeatedly through its mass, in a circular 

 course. In conducting this experiment we shall find that the sur- 

 face of the fluid immediately becomes depressed by the centrifugal 

 action, except on its exterior portions, where, owing merely to the re- 

 sistance which is opposed by the sides of the vessel, it will rise above 

 its natural level, the fluid exhibiting the character of a miniature vor- 

 tex, or whirlpool. Let this experiment be carefully repeated by 

 passing the propelling rod around the exterior of the fluid mass, in 

 continued contact with the sides of the vessel, thus producing the 

 whole rotative impulse by an external force, analogous to that which 

 we suppose to influence the gyration of storms and hurricanes, and 

 we shall still find a corresponding result, beautifully modified, how- 

 ever, by the quiescent properties of the fluid ; for instead of the 

 deep and rapid vortex before exhibited, we shall have a concave de- 

 pression of the surface, of great regularity, and by the aid of a few 

 supended particles, may discover the increased degree of rotation 

 which becomes gradually imparted to the more central portions of 

 the revolving fluid. The last mentioned result obviates the objec- 

 tion, which, at the first view might, perhaps, be considered as op- 

 posed to our main conclusion, grounded on the supposed equability 

 of rotation in both the interior and exterior portions of the revolving 

 body, like that which pertains to the rotation ol' a wheel, or other 



