The Madisonian. [volume] (Washington City [i.e. Washington, D.C.]) 1837-1845, 1840-12-12
THE MADIS0NIAN.
OUR NAVY:
EroB, The Southern Literary Messenger.
DETAILS OF THE SCHOOL-SHIP.
Continued.)


Erom ne Southern Literary Messenger
DETAILS OF THE SCHOoL-SHIP.
(Continued.)
Magnetism too has been called on 10 aid in
the solution of the grand problem OF terrestrial
longitude. Variation charts were constructed at
4 very early day. But modern Improvements
have invested this science, hitherto but little
derstood with a new importance, and given II
an interest which il never before possessed. As
an auxiliary in the development Of the laws of
magnetism, charts have been also constructed TO
show the lines of equal inclination and intensity
aswel as of variation. These lines, apparently of
faucilul commissions, and of arbitrary course and
Texture are found on examination TO be governed
BY fixed principles; whether under the form of
lllnes, assymptotes, lemniscates, or circles or,
IN the many carnations of conjugate oval, cusp,
and node, in which the geometry of curves luxu-
rates" they are the opponents OF magnetic quail
ues, regulated by mathematical rule, in obed-
ence 10 certain laws of physics, which present
research is seeking more fully to investigate. In
his magnetic storms, Humboldt, few years
ago, discovered new principle in magnetism,
which, when properly investigated and fully I'M
derstood, may lead to most important results
afording the means of determining longitude
with an accuracy hitherto unknown. 1t is inn
possible TO calculate the bearings on the economy
of mankind which the discovery of any new
principle in physics is destined to have, however
nlhing that principle may appear when first re-
yealed The fall of an apple, and the motion OF
frogs leg in the kitchen of philosopher, have
led TO the most important results, and given
powers to man, the extent and value oil which,
though already great are not yet fully developed.
The discovery of Humboldt has revealed, In the
cosmical circulation Of the magnetic fluid, the
existence of pulse, which is found to be syn
erroneous in its action over all parts of the world
where observation has as yet been directed to'the
subject The beats occur at intervals, and, act
ing simultaneously on the needle every where
this discovery may constitute natural telegraph
in perpetual operation, for the communication oil
longitude. Impressed with sense of the i'm
portance with which this science has thus been
invested, the Pacha of Egypt, and the semi barba
rous Rajah of Hindoo PROVINCE in concert
with England, Russia, Belgium, Austria, Prus-
STA and Bavaria, joined by few private citizens
of America, are at this time engaged in conduct
ing a grand series Of magnetic observations OF
which Gottingen is the centre,--the outskirts
reaching from Siberia 10 voyage OF clrcumpo-
lar navigation in the Antarctic ocean. With
such an impulse and under such auspices, the
laborers are already clearing away the rubbish
in this branch of knowledge. The work OF a
few years past is throwing down the rude scat
folding of former theorists; and IN It's place
something is seen rising up. like the pillar and
spire of a less fanciful edfce, having the rigid
hut beautiful proportions of an exact science
Yet course of magnetism constitutes no part
Of the professional education of the American
Navy officer The Midshipman who seeks to
become learned in the branches of science that
pertain to his profession, and who, before the
Examining Board, should so far stray from the
lids of Bowditch, as to get among the isodyna-
mic and other lines of magnetic chart, would
We black baled as certainly as though he were TO
chb-haul ship for the Board in the Hebrew
tongue Such is the present system, that the
young officer finds but few Incentives, and no
Official nducement TO undertake an extensive
course of professional studies.
If YOU will examine the records OF mad
house among any commercial people, OF little
more than half century ago, you will find there
frequent instances of men who had cracked their
heads upon Longitude at sea- Large rewards,
both by governments and individuals, were Of
fered for the practical solution of this problem.
II was even classed by some with perpetual mo-
ton and the quadrature of the circle. Yet, now
that il is understood, il is quite as easy for the
scientific navigator 10 ascertain the longitude OF
his ship. as il was TO resolve Columbus problem
Of the egg, after the demonstration. And in
these DAYS, the wonder is, not how the solution
of the problem for finding longitude was dis
covered but how il remained hidden so long,
so obvious and so papable were the means OF the
guGsifum The whole secret Of the matter
consists in knowing the difference between the
time of day at the ship and at any other place.
borrowing an idea ON the beautiful
smle of DIR. Wolaston-the moon is the hand
Of great clock, placed by God in the sky, for
this purpose Therefore, he who can tell the
time by the celestial clock, knows the longitude
Of his ship.
Another method, more simple, but less infall-
bic and therefore not so beautiful, for determip-
ing longitude, is found in the substitution of a
watch in the cabin of ship, for 1.-THE great
Greenwich clock in the sky" This watch Is set
hy Greenwich time, and. supposlng II TO run
correctly, always shows The true time at the
Roya Observatory. Then all that remains 10
be- done for finding longitude, is TO tell the time
oI day by observation at the ship. But how can
the place of ship be known, by rejecting the
sun in a little mirror, and bringing its image 10
lhc horizon? Or how can it be discovered, by
booking through a brass tube at the moon, and
moving an index along the arch OF a sextant
hat, IL may be asked by those unacqualnted
with the principles, have the sun and moon ~
The sky, those things in the sextant, TO do with
ship on the ocean? When told of Augmen-
tauon, Semldiameter, Dip, Parallax and Refrac.
ton; Of the Equation Of time, Of Horary an
giles. Azimuth circles and Zenith distances,
Right Ascension and Defamation of the incli-
Lond ar Review No CXXXI