The combined labours of Redfield, Reid,
Maury and others have demonstrated beyond
a doubt that the hurricanes, tornadoes, typhoons
and other named storms, are nearly
identical in character, being in fact, vast
whirlwinds moving onward by a fixed law,
from east to west. It is known, also, that
these whirlwinds revolve in contrary directions
on opposite sides of the equator: in
the southern hemisphere they move round in
the same direction as the hands of a watch,
from left to right, whilst, in the northern
seas they revolve from right to left. Thus
the side of one of these cyclones nearest the
equator, in either hemisphere, will be a westerly
gale, whilst, on its polar margin, the
storm will be from the east.

These cyclones, as they are now termed, do
not move in a due westerly direction alone;
but attain a polar inclination as they progress,
and, towards their termination, recede somewhat
to the eastward, so that they form the
figure of a section of a circle, gyrating in
curves more or less extended according to the
rate of progress of the storm. The speed at
which these cyclones travel, varies continually
between two miles and forty-three miles an
hour: at times they have even been known
to remain stationary for a considerable period.
The gyration of these progressive storms may
be fairly represented by an ordinary coil of
rope, somewhat opened out, and spread in a
quarter circle.

Mr. Redfield's explanations of the cause of
the rise and fall of the mercury during these
gales, tells us that one of these cycloidal storms
which sets a considerable portion of the atmosphere
in a state of rapid revolution, diminishes
its pressure over that particular
track, and most of all so towards the centre
of the whirl. Consequently the depth of the
superincumbent column of air will be least
at the centre; and its weight will be diminished
in proportion to the strength of the
wind.

This idea may be illustrated by means of
a tumbler half filled with water, and put
in rapid motion by passing a rod round the
inside of the vessel. On looking at the
contents of the tumbler it will be perceived
that the surface of the water is depressed at
the centre, and rises against the side. The
centrifugal force exerted, causes this heaping up
at the sides of the glass, but the reverse in the
case of whirlwinds, which have limits to confine
them. The tendency of the atmosphere
thus set in rapid rotation is, consequently, to
fly off from its centre, lessening thereby the
weight of the incumbent air, and causing
a fall of the mercury in the barometer.
This flying-off would bring down a portion
of the old stratum of the upper atmosphere,
which, coming in contact with the humid
stratum of the surface, produces a continuous
layer of clouds, and a copious supply of
rain — the usual accompaniment of cycloidal
storms.

Let us see how the knowledge of all this, as
set forth by the Hornbook of the Law of
Storms, enables the commander of a ship,
who will give a little attention to the
subject, to take his vessel out of a cyclone
with almost certain impunity: Any captain
overtaken by, or inadvertently running into
such a hurricane, can escape from its influence
by ascertaining the ship's position in
the cyclone, and endeavouring to reach its
outer edge.  In ignorance of this, a vessel
may be forced into the very centre of the
whirl.

To scud or run, either partially or wholly,
with the gale, is to be avoided, as only calculated
to retain the ship within the gale. The
most prudent plan is to bring the ship's head
to the wind, — in nautical terms, to "bring
her to,"— and, in that position, with just sufficient
head-sail set for the purpose, to wait
the passing-over of the storm.  In putting this
in practice, however, judgment is required
in order to prevent the wind heading the
ship, which might cause her to founder. The
force of the wind on the masts and rigging
alone is sufficient to do this; and it is believed
that many ships have been thus lost. The
rule of action in such a case, as laid down by
the Hornbook, is, " to heave-to on the starboard
tack when on the north side of the
equator, and on the port tack when on the
south side of the equator." A ship so placed
will have the gale veer round more towards
the stern, when the head could be at once
brought close to the wind in its new direction,
until at length the cyclone would fairly
blow over, and leave the ship in its rear;
whereas, if the ship were so laid-to that the
next shift of wind took her aback by blowing
directly against her head, she would perhaps
sink stern foremost.

By keeping the wind on the starboard quarter
in the northern hemisphere, and on the port
quarter in the southern, a ship may be gradually
sailed from the centre of the storm.
But there is always one quadrant of the
hurricane-circle replete with danger in such a
course: it is that portion which would immediately
carry a vessel within the path of the
centre whirl of the advancing cyclone. With
the storm advancing due west in the northern
hemisphere, the quadrant of danger would be
in its north-western quarter; in the south, it
would be in the south-west. In its polar
progress, when north, the dangerous quadrant
would be in the north-east. On the opposite
side of the line it would be in the south-east.
An imperfect acquaintance with the
Law of Storms, or a careless application of it,
may lead a commander into more danger
than if he had never seen a Hornbook, or
had thrown his barometer overboard. It is a
law which must be studied attentively, or not
at all.

The barometer is not the sole indicator
of the approach of a cyclone. The storm
sends before it a herald, which, outstripping