128 On the Gales and Hurricanes of the Western Atlantic. 



The action of these storms appears, indeed to be at first confined to 

 the stratum or current of air moving next the earth's surface, and 

 they seldom, while in this position, appear to exceed a mile or so in 

 altitude ; and the course of the next highest or overlying stratum 

 does not in these cases seem to be at all affected by the action of the 

 storm below. During their progress, however, by the influence of 

 high land and other causes, the storms often become transferred, in 

 whole or in part, to the next higher stratum of current. Thus we 

 sometimes see a stratum of clouds moving with the full velocity of a 

 violent storm, while the stratum of surface wind is nearly at rest, or 

 moves with its ordinary velocity ; and thus also it happens that bal- 

 loons, ascending under such circumstances, are carried forward with 

 a velocity of from sixty to one hundred miles an hour. The forego- 

 ing remarks are by no means hypothetical, but are the result of long 

 continued observation and inquiry.. 



It will hardly escape notice that the track of most of these hurri- 

 canes, as presented on the chart, appears to form part of an ellipti- 

 cal or parabolic circuit, and this will be more obvious if we make 

 correction, in each case, for the slight distortion of the apparent 

 course in the higher latitudes, which is produced by the plane pro- 

 jection. We are also struck with the fact that the vertex of the 

 curve is uniformly found in or near the 30th degree of latitude. In 

 connection with this fact it may also be noted, that the latitude of 

 30° marks the external limit of the trade winds, on both sides of the 

 equator ; and perhaps it may not prove irrelevant to notice, even 

 further, that by the parallel of 30^^ the surface area, as well as the 

 atmosphere, of each hemisphere is equally divided ; the area between 

 this latitude and the equator being about equal to that of the entire 

 surface between the same latitude and the pole. It is not intended, 

 however to make these facts the basis of any theoretical inductions 

 on the present occasion. 



It will doubtless appear desirable to know whether, if the full his- 

 tory of these or other storms could be obtained, the track in any 

 case, would result in the completion of an entire circuit, either in 

 the proper basin of the North Atlantic, or in its continental borders ; 

 and if so, whether there be, or be not, any general uniformity in the 

 length of the major axis of this elliptical circuit at different seasons 

 of the year ? If this inquiry cannot be satisfactorily solved, it is still 

 important to learn the analogies or relations which the storm-tracks 

 on the eastern borders of an oceanic basis, bear to those in its western 

 portions, or in other regions. On the Asiatic coasts of the northern 



