The San Francisco call., 1906-11-04

It's full violence was attained. after
which II would gradually blow itself
out. all from one quarter. Such. how
ever, Is never the case. In addition to
the movement OF the air around the
storm center there is a progressive
movement OF the center itself. carry
ing with 1T It's circulating system OF
winds.
The velocity OF the progressive mo-
tion OF the storm center varies. With
in the tropics IL rarely exceeds ten
miles an hour. being here much more
regular than in higher latitudes. where
the velocity ranges from zero. the cer-
ter at times appearing to become all
but stationary. up to forty miles an
hour.
The present theory OF tropical cy-
clonic storms requires that there shall
exist at the center. toward which the
fncurving surface winds are directed.
a rising column OF warm. moist air.
Upon reaching the higher levels OF the
atmosphere the water vapor borne aloft
by this air is condensed into clouds.
which are carried by the now outward
curving winds away from the center
on all sides. These clouds. then, which
are formed at a great height and are
OF the cirrus type. radiating in long
feathery streameTs from the region OF
the ascending column. constitute for
the sailor the best Indication of the
approaching typhOon. sometimes maxi
ing their appearance when the storm
center is 1900 miles distant. As the
center approaches the density Of the
cloud canopy deepens until the belt
OF nimbus. from which torrents OF rain
descend. is attained. The width OF
this belt in front of the center is. IN
general, about $50 miles; in the rear It
is less.
"A vessel warned by her barometer
and by the character of the winds and
sea that a typhoOn is approaching
should. IL sea room permits. seek to
avoid il by running. In general terms
1T NAV be said that the semicircle OF
the storm toward the equator is the less
dangerous. as storm eenters In both
hemispheres show a decided tendency
to constantly move toward higher alti-
tudes. vessel. therefore. in this semi
circle is free from the danger OF again
meeting the hurricane after recurring
eff the fall of the barometer and the
shifts OF the wind are slow II means
that the storm Is yet at q distance. and
a swift vessel, westward bound In low
latitude taking advantage OF the IN
creasing favorable winds. may manage
to outstrip 1t and thus escape the loss
OF time incidental to heaving to or
seeking the southern seuicircle.
vessel, however, borne to leeward by
the temporary surface currents pro-
duced by the storm winds, will In gen.
eraI. be compelled to cross the storm
track, in order to avoid the center In
both OF these maneuvers the wind
should be kept well on the starboard
quarter, the effect OF this being to
carry the vessel constantly from the
storm center. In the vicinity OF ty-
phoon the vessel should never run for
any length OF time with the wind dead
aft.
'It IS. however. only IN the outlying
portions OF the storm that IL Is possible
to carry sail. Near the center the ves-
sci must be hove-to under as little can
vas as possible. and much depends upon
this being done upon the proper tack
Hurricanes do not occur in the win
ter time. They are most frequent In
August. September and October There
have been a few cases on record of hur-
ricanes occurring before June. but they
are rare. From June until November IL
behooves the navigator traversing
tropical waters to be on his guard
against hurricanes In the southern
hemisphere. OF course. where the sea-
sons are reversed. the months OF the
year in which violent cyclonic storms
may be encountered are the reverse OF
those in the northern hemisphere
In conclusion. il may be said that thu
West Indian hurricanes and their coun-
terpart, the typhoon OF the China seas.
are the worst storms in the world. But
the increase IN our knowledge OF their
nature and the advances in naval archi-
lecture and In seauhnship have les
sened their dangers to a well found.
well managed ship. A skillful navi-
gator will avoid them, or the worst
parts OF them; good. stanch ship
may even weather them IN safety, pro-
vided she has enough sea room In which
20 maneuvsr.