The republic. [volume] (Washington [D.C.]) 1849-1853, 1850-09-02
From the Pennsyloanian.
.'SwiDsing the Ship"-ImpOrtnnt to Mer-
chants and Under riters.

"Swinsing the Important to Mer-
chants and Underwriters.
A recent number of "Household Yordsn con-
tains an article entitled Swinging the Ship" in
which Dickens describes process for correcting
errors OF the compass, produced by disturbing
causcs on board vessels of war. In the course of
seem to be important to the shipping merchants
and seamen of all countries. We have conse-
quenty prepared brief sketch of the article re-
fcrred to, for the use Of such have not time or
opportunity to read the original. The object OF
Dickens demanded arrang cement of details and
particularly OF description not necessary to
purpose; In some cases, therefore, we have
arranged and condensed his matter, but wherever he
speaks directly TO the points we have in view, his
language is used without alteration.
Ii appears that Great Britain loses by wrecks be-
tween five and six hundred ships year, or about
three vessels in every two days. To account for
this terrible loss great many different causes
given-the tides and currents of the ocean-imper
feet logs-inaccurate charts-unsteady steerage-
inattention to the lead-stress of wcather-detec-
tive ships and detective mana cement; all Of which
have no doubt done their work, but still there
blundcrs and disasters for which they will not sat
isfactorily account. AZ, for instance, merchant
vessels under convoy in time of war have answer
ed at sunset to the general signal to keep close, by
steering given course during the night, and yet
at daylight have found their protectors far away,
and themselves dispersed in every direction over
the as far as the eye could reach-somc perhaps
in possession of the enemy. Neither will the causes
above recited for the loss of the Apollo fri
gate, and her convoy of forty merchantmen, on the
coast of Portugal, in 1903, when they supposed
themselves to be two hundred miles 10 the east
ward-nor the dreadful wrecks on the coasts of Jut
land and Holland, in lsll-nor the loss of the Re-
lance Indiaman on the coast of France in 1912: all
of which occurred under like circumstances. In
stances of a similar character occurring the
coast OF the United States will suggest themselves
to readers. The beaching of the Tuscarora
below Cape Henlopen when che was thought TO be
fifty miles to the south, is fresh in the memory Of
Philadelphia merchants.
Leaving out the partial wreck of the Tuscarora,
an account of which we have not at hand, the only
sufficient explanation in the above cases is that
which assigns the disasters to errors of the =
pass. These errors have been noticed by careful
mariners Tor more than century. From time 10
time they have called attention the subject, and
at last lney attracted official attention in England
! Inquiries were extended in every dircction--tho
/ greatest care was taken in the manufacture o
compasses-lnvention and ingenuity were taxed
TO the utmost for of correcting varis tons
but all would not DO for the ,oiids.t pro
duced by disturbing causes board ship. The at
tractivc power OF the guns Of vessels OF war-thC
presence of tanks and funncls-even the iron uscC
in the construction of ship affect the compass in
vessel more, in another lcss-bu in all in pro.
portion to the weight and position Of the metal on
board.
Thcse facts were investigated by committee OF
English officers and it was found that " in some
ships the deviation Was small in others il was
large enough 10 cause the loss of a ship even dur
ing short run whilst in others again, from the
position of some bolt bar, stand of arms, the
might be changed in another direction; 50
that the deviation in vessel was guide to its
amount in another; and that there other
remedy but ascrrtoining The fact by direct eIPsrin'Ht
on board each ship"
This led to the establishment of the Compass
Observatory" in England, where every ship Of the
royal navy has its compass adjusted previous to
setting sail long voyage. IL is fret compared
with standard instruments in the observatory-its
variations, after nice observation aud experiment,
noted and corrected; is then fixed in the position
il is to occupy on beard ship-the guns and other
iron being round about il, they arc TO remain
during the voyage-when the dcviatiops, some
times very great, resulting from It's present posi-
ton, discovered and corrected by the pros css
called "swinging the ship which it is not neces-
sary 10 our purpose to describe. Up to this time,
however, notwithsta ndng the dreadful less Of life
and property resulting from errors of the compass,
they are uDrtcogntsed or unattended 10 in the mucdH-
nic marine; but no British ship of war leaves the
shores VI England without being subjected to the
process referred To. Some OF the officers do not
like it, II s apt TO spoil the paint, and gives trou
BILE, and upsets their private arrangements. The
opera ation il sometimes salutcd with growl about
"nev tangled fancies," that "giye deal of trou-
be," but II goes on, nevertheless and there is but
little doubt that the trouble is forgotten, and the
growl repeated when, "iar, far at sea n murky sky
shuts out the and stars, and forbids heaven tu
tell the navigator where he is. With waste OF
waters, hundreds, perhaps thousands Of miles
around him, he has nhught but his figures, and hi.
little trembling needles To guide him on his way
60 direct him wide Of the sunken ruck and sandy
shOa, az he nears the wished for coast"