Staunton spectator. [volume] (Staunton, Va.) 1849-1896, 1858-03-17
sTAUNTON VIRGINIA, WEDNESDAY, MARCH II, 1853.
The Tides.

Many persons still seems TO be much perplex
ed with the phenomena of the tides. They can
not understand why they are higher at one tim,
than another, nor why they rise to the heigh
of sixty feet in the Bay OF Fundy, forty feet il
the ports of Bristol, England, and st. Malo
France. and only rise to few feet in height il
New York and other places, while they are
scarcely perceptible in the Baltic and other seas
Descartes was the first philosopher who advanc
ed the theory that the tides were due o the in
1uence of the moon, but Newton was the frst
who worked out the problem, and diccvered the
true cause Descartes believed that the moon
acted on the waters Of the ocean by pressure
Newton demonstrated that it acted upon the 0.
cean by attraction that instead OF pressing the
waters, it rolled them up directly under it, and
also at its antipodes at the same time, thus pro.
ducng the two tides every day. The tides are
caused by the attraction OF both the moon and
the sun. If this earth had no moon, the attrac-
ton Of the sun would produce two tides every
day, but their ebb and flow would take place at
the same hours regularly, not varying as they do
now; 'hese tides would alsc be much smaller
than those of the moon. Although the mass OF
the sun is far greater than TINT of the moon, and
although attraction is in proportion to the mass,
vet it is also inversely as the square of the dis
tance. As the sun, therefore, is four hundred
times further distant than the moon, the attrac-
ZION of the waters of the sea towards the sun Is
found to be about three times less than that OF
the moon; the tides produced by the sun would
therefore be three times less than those of the
moon. There are really two ocean tides, the Ill.,
mar and solar, but the latter is absorbed by the
former, which is wholly observable in respect
to time the solar only as it influences the height
of the tidal wave That caused by the moon is
three times greater than that of the sun, and II
follows the moons motion around the earth, RI
sing and falling every twelve hours, aud each
succeeding tide later by three quarters of an
hour than the preceding one, exactly in accord
ance with the positions of the moon, or as it is
commonly called, sits rising and setting"
! Sometimes there are very low, and at other
times very high tides-that is their height is not
uniform. This is caused by the positions OF the
sun and moon relative to the EARTH Thus as at
the time of the new moon, the sun and moon
being in the same parts of the heavens-the
tides produced in the ocean are then the high.
est, because they are equal to the sum OF the
two tides-lunar and solar. This should also
take place at the time of full moon when our
satellite is opposite the sun, the attractive force
being equal and opposite, in producing the IT,
dal wave. This is found to be true. The tides
are greater at new and full moon than at the
first and last quarters, during the latter peri
ods the attraction Of The sun, not acting in uni
son with that OF the moon, tends to lower the
tides.
Reasoning from this data, it will naturally be
inferred that when the sun and moon are equal
ly distant from the two poles of the globe, such
as the times of the uquinoxes in March and Sep
tember, the tides would be greatest. This is al
so found to be the case, th;is demonstrating be-
yond all doubt that the tlux ard refux of the
sea are due to the attraction of the sun and
moon on the waters of the ocean. The differ
ence in the height of the tides at various places
is due to the peculiar formation of sea coasts
They are very high in the Bay of Fundy, be.
cause an immense quantity Of water is piled in
to wide mouthed narrow space, in the same
manner that certain quantity of water will
rise higher in narrow than wide channel.-
Some have advanced the popular belief against
the lunar influence causing tides, namely, that
the Mediterranean is tidcless sea. This is not
strictly true. The ocean tides, owing to the
narrow passage into the Mediterranean at Glib
ratar, scarcely affect this sea, but for all this
there are regular tides observable at some pla-
ces. At Vicenza they sometimes rise to two
feet, and in the Faro of Messina to twenty inch
Ies.