Hurricanes and Storms of the West Indies, <§•£•. 323 



storm being estimated both by actual information and by its 

 duration at any point near the central portion of its route, as 

 compared with its average rate of progress. The figure which 

 appears upon the chart, on Tracks No. I, V, and VII, will serve, 

 in some degree, to illustrate the course of the wind in the va- 

 rious portions of the superficies covered by the storm, and also 

 to explain the changes in the direction of the wind which occur 

 successively at various points, during the regular progress of 

 the gale. The dimensions of the several storms appear also to 

 have gradually expanded during their course. 



Storms of this character do not often act with great violence 

 on any considerable extent of interior country to which they 

 may arrive. Even upon the coasts on which they enter, such 

 violence is not often experienced under the posterior limb of the 

 gale which sweeps back from its circuit over the land, the 

 usual woodlands and elevations being a sufficient protection. 

 Often, indeed, the interior elevations afford such shelter as en- 

 tirely to neutralize the effect of the wind at and near the sur- 

 face, and the presence and passage of the hurricane is, in such 

 cases, to be noted chiefly by the unusual depression, which the 

 great whirling movement of the incumbent stratum of air pro- 

 duces in the mercury of the barometer, which thus indicates the 

 presence or passage of the hurricane, in positions where the 

 force of the wind is not felt at all, or only with a moderate de- 

 gree of violence. 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 overlaying stratum does not, in these cases, 

 seem to be at all affected by the action of the storm below. 

 During the 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 balloons, ascending under such circumstances, 

 are carried forward with a velocity of from 60 to 100 miles 



