San Antonio daily light. [volume] (San Antonio, Tex.) 1886-1907, 1890-10-22
SHIPS CoMPAssEs.
Their Strange Behavior During a
Typhoon.

Their Strange Behavior During a
Typhoon.
New York Sun.
"Do you know said Capt. Fisher,
of the British steamer Sirius, "that
the COMPARISON our iron vessels is a
rource of endless trouble and anxiety?
1t seems strange that since the days
of Marco Polo. in the thirteenth GEN.
fury, hardly any improvement has
been made IN the compass, and all
the so-called patents have proved
worthless as fas as the safety of q
ship is concerned. Nearly all the
patented devices, after q brief trial,
have been abandoned, and the worst
feature about the whole thing Is that
just at the time when you have to al
most absolutely rely upon your COM
pass, 1T proves to be of no earthly
value.n
SIN what way?"
"Why, it no longer determines the
course of your vessel. This is es-
pecivlly true of the action of the
needle in the Chinese sea and Indian
ocean during the typhoons, which 80
iiCHuChpl1 NlStU tIc5o W1OcIb.
"The popularity of the action of
the compass on those occasions is that
every time a squall strikes the ship
the card will spin round and round
like a thing possessed. Eight points
is nothing for a spin, and SO there is
nothing for it but to steer by the roll
of the sea and the feel of the wind.
Even after the typhoon has subsidized,
it takes hours for the needle to be-
come normal"
"To what is this attributed geHer-
allyn.
"The commonly received opinion is
that the phenomenon is caused by the
squalls being charged with electricity
which acts upon the magnet. There
are many causes, however, which
tend to render the compass unreliable
upon iron vessels, and there is moth
ing for it but to have compasses care
fully corrected and adjusted on every
opportunity. The natural local va
Ration and the deviation due to the
magnetism of the vessel and the man.
ner in which her cargo is stored must
be carefully noted ii a correct course
is to be steered. Even the very course
to be steered should, if POSI-
BILE, have the compass error
determined for it; for strange
as it may seem to q lands
man, sometimes a vessel will show de-
Walton on II course and one at all
upon another. Even the rays of the
moon concentrated upon the card can
defect the needle fully five points.
Then, again, the magnetism of an
iron vessel Is not constant. The
plates of a ship become magnetic by
the mere hamering upon them.
When first launched, an iron ship is
a very strong magnet, but her mag
netism gradually decreases. In iron
steamships no two compasses agree,
and all that can be done Is to deter.
mine the error of one compass from
the magnetic course, and SO determine
the error of the Others"
''Is there any remedy for this, Cap
tain?"
"Well the latest attempt to RENEE
dy it has been made by Lieut.. DiehI,
Naval superintendent of Compasses,
of your service, who, together with
his assistant, Ensign Gilbert, has
invented a compass designed to, by
compensating magnets, overcome the
local magnetism of. the ship. The
invention has yet to be practically
tested.
"By the way" continued Captain
Fisher. 81 read in a paper once that
when the right of discovery in Amer
lea was given by Rome to the Crown
of Spain, at the request of Columbus,
the line of no variation was estab-
lished as the boundary beyond which
all discoveries should belong to
Spain. At that time the line of 10
variation was in the Atlantic Ocean.
Now it is near Pittsburg, Pa. Quite
a change, eh?"