208 Test of Mr. E'spy’s Theory. 
this, as in some of the former cases, the field of action of the whirl- 
wind storm will have-been in part mistaken. I would also re- 
mark, that the points at issue, do not relate to the common and 
often irregular winds, which, in different localities, accompany a 
general fall of rain or snow; or which sometimes attend the pro- 
— ot a whirlwind — exterior to si a 
ms Test of Mr. Flan: pocnel 
~ 
The truth or error of Mr. Espy’ S theory may be. acetate i 
avery simple test. The hurricanes in the West Indies are known 
to move towards the, W. N. W. , nearly. Now, if this theory be : 
true, at those islands which are in’ the centre af the storm’ s path, 
and where the gale i is of the greatest duration, the wind will set in 
at about W.N. W., or exactly opposite to the course of the storm, 
and when its centre has passed over, will shift suddenly. to E. 8. 
E., and continue violent in this quarter till the storm is over. But 
if :* gale be a whirlwind, as the facts seem to show, the wind 
at such places will set in at about N. N. E., and in the middle. of 
the gale will shift nearly to 8. S. W. the wind varying from 
these points, and veering moré gradually, on either side, in propor- 
tion to the distance from the centre of the. storm’s track. “That 
this corresponds, mainly, to the facts of the case, will hardly be 
doubted by those who fretiends the i inquiry. - 
- The same test: ‘may also, be applied to ges storms as they move 
ina N. E. direction along the shores of the-United States ; ea 
according » to “Mr. ‘Espy’ S$ views, the gale, on the centre of its patl 
should blow, for the first part of its duration, from about N. E.; 
and in the second half, from nearly S. W.* But all our-inquiries 
serve to show, that the gale is violent at N. E. only on the northern 
portion of the track of the tempest, and that the usual changes 
from this direction, are not sudden, and to- an opposite point of 
the compass ; but, instead thereof, we observe a gradual veering, 
by the north, to the northwest. 
~" 
? a 
* Some storms, as Mr. Espy hae also bape = are peti in their de- 
velopment by the near approach of anot her storm. Care must be taken, therefore, 
not to mistake the N. E: wind of a storm whose northwest m oe is thus inter- 
* bordering storm, and which hence is sometimes followed by the natural 
current of air from the S. W. quarter, for the —— that pertain to the centre 
of the gale. } error is easily avoided by extending the field of er and 
by a due attention to ty the tadieasiode-af tha bacimater. 
‘, 
