e vortex may still produce a storm on a line of low barometer
to the west, and this line may reach the ship at the time of the
passage. In tropical climates the trouble must be looked for to the
eastward; as a storm, once excited, will travel westward with that
stratum of atmosphere in which the great mass of vapor is lodged, and in
which, of course, the greatest derangement of electric tension is
produced.

It will now be seen that we do not admit, with Col. Reid, that a storm
continues in existence for a week together. Suppose a hurricane to
originate in the Antilles at the southern limits of a vortex, the
hurricane would die away, according to our theory, if the vortex did not
come round again and take up the same nucleus of disturbance. On the
third day the vortex is found still further north, and the apparent path
of the hurricane becomes more curved. In latitude 30d the vortex passes
over 3d or 5d of latitude in a day; and here being the latitude where
the lower atmospheric current changes its course, the storm passes due
north, and afterwards north-east. Now, each day of the series there is a
distinct hurricane, (caused by an increase of energy in a particular
vortex, as we have before hinted,) each one overlapping on the remains
of the preceding; but in each the same changes of the wind are gone
through, and the same general features preserved, as if it were truly a
progressive whirlwind, except that each vessel has the violent part of
it, as if she was in the southern half of the whirl. The apparent
regularity of the Atlantic storms in direction, as exhibited by Col.
Reid, are owing in a great degree to the course of the Gulf Stream, in
which a vortex, in its successive passages in different latitudes, finds
more favorable conditions for the development of its power, than in
other parts of the same ocean; thus showing the importance of regarding
the established character of storms in each locality, as determined by
observation. In this connection, also, we may remark, that the meridians
of greatest magnetic intensity are, _ceteris paribus_, also the
meridians of greatest atmospheric commotion. The discovery of this fact
is due to Capt. Sabine. The cause is explained by the theory.

As it is the author's intention to embody the practical application of
this theory to navigation, with the necessary rules and tables, in a
separate work, sufficient has been said to familiarize the reader with
the general idea of a