The Hurricane Guide | Page 2

attention to the annexed engraving,
fig. 1.
[Illustration: Compass rose]
In this figure the arrow-head is supposed to be directed true north, and
the hurricane--as is the case in the American storms north of the 30th
parallel--to be moving towards the N.E. on the line N.E.--S.W. If the
ship take the hurricane with the wind S.E.,--the letters within the two
larger circles indicating the direction of the wind in the storm according
to the rotation as shown by the circle of arrow-heads, and which it is to
be particularly noted is in the northern hemisphere contrary to the
direction in which the hands of a watch move: in the southern
hemisphere the rotation is reversed--the only phænomena presented by
the storm are as follows:--The wind continues to blow from the S.E.,
increasing considerably in force with the barometer falling to a very
great extent until the centre of the storm reaches the ship, when the fury
of the winds is hushed, and a lull or calm takes place, generally for
about half an hour, after which the wind springs up mostly with
increased violence, but from the opposite quarter N.W., the barometer
begins to rise, and as the storm passes off, the force of the wind abates.
The point to which we wish particularly to direct attention in connexion
with this exposition of the phænomena attending the transmission of a
storm is this:--If the observer so place himself at the commencement
that the wind passes from his left hand towards his right, his face will
be directed towards the centre of the storm; and the wind undergoing
no change in direction, but only in force, will acquaint him with this
important fact that the centre is not only gradually but surely
approaching him: in other words, in the case before us, when he finds
the wind from the S.E., and he places himself with his face to the S.W.
he is looking towards the centre, and the wind rushes past him from his

left to his right hand. Now the connexion of the barometer with this
phase of the storm is falling with the wind from left to right, the
observer facing the centre while the first half is transiting.[1] During
the latter half these conditions are reversed, the observer still keeping
his position, his face directed to the S.W., the barometer rises with a
N.W. wind, which rushes past him from his right to his left hand with a
decreasing force. We have therefore a rising barometer with the wind
from right to left during the latter half of the storm, the observer having
his back to the centre.
The above general enunciations of the barometric and anemonal
phænomena of a rotating storm hold good with regard to the northern
hemisphere, whatever may be the direction in which the hurricanes
advance. This may be placed in a clearer light, as well as the remaining
classes of phænomena shown, by consulting the following tables,
constructed for the basin of the Northern Atlantic, and comparing them
with fig. 1. In this basin, with lower latitudes than 25°, the usual paths
of the hurricanes are towards the north-west, in higher latitudes than
30° towards the north-east. The tables exhibit the veering of the wind
with the movements of the barometer, according as the ship is situated
in the right or left hand semicircle of the hurricane. It must here be
understood that the right and left hand semicircles are determined by
the observer so placing himself that his face is directed towards the
quarter to which the hurricane is advancing.
LOWER LATITUDES.
NORTHERN HEMISPHERE.
Axis line, wind N.E., barometer falling, first half of storm. Axis line,
wind S.W., barometer rising, last half of storm.
RIGHT-HAND SEMICIRCLE.
Wind E.N.E., E., E.S.E., S.E., barometer falling, storm increasing.
Wind S.S.W., S., S.S.E., S.E., barometer rising, storm passing off.
LEFT-HAND SEMICIRCLE.

Wind N.N.E., N., N.N.W., N.W., barometer falling, storm increasing.
Wind W.S.W., W., W.N.W., N.W., barometer rising, storm passing off.
HIGHER LATITUDES.
NORTHERN HEMISPHERE.[2]
Axis line, wind S.E., barometer falling, first half of storm. Axis line,
wind N.W., barometer rising, last half of storm.
RIGHT-HAND SEMICIRCLE.
Wind S.S.E., S., S.S.W., S.W., barometer falling, storm increasing.
Wind W.N.W., W., W.S.W., S.W., barometer rising, storm passing off.
LEFT-HAND SEMICIRCLE.
Wind E.S.E., E., E.N.E., N.E., barometer falling, storm increasing.
Wind N.N.W., N., N.N.E., N.E., barometer rising, storm passing off.
N.B. The directions of the hurricane winds are so arranged as to show
the points of commencement and termination. Thus in the lower
latitudes a storm commencing at E.N.E. passes off at S.S.W. after the
wind has veered E., E.S.E., S.E., S.S.E., and S., being in the order of
the letters in the upper line and contrary to their order in the lower. One
commencing at E.S.E. passes off at S.S.E. right-hand