The Kanzas news., 1858-03-13
The Tides.

llCSSOA WO1UCl 814 p0E<1S ~ S1OoC WV
have not investigated their cause. 1t Is re-
lated of the soldiers of Alexander the Great,
who were natives of the Mediterranean
of the Indian Ocean and saw its waters
rolling up to great hight, and then flow-
ing back, twice every day, that they became
alarmed, and attributed the phenomena to a
special interposition of the deities of the
tcountry which they had invaded. Various
remarkable theories have been advanced re-
garding the causes of the tides. Kepler,
the celebrated astronomer. believed that the
earth was real living animal, that the tides
were due to It's respirations, and that men
and beasts were like insects feeding on its
back. The tides have also been attributed
20 the waters of the ocean running in and
out through some great hole, at each pole,
communicating by subterranean passage
through the earth !; and the Malestrom-
now myth-that whirlpool on the coastof
Norway, has been suggested as an opening
into this supposed underground canal. We
would not be very much surprised if spec
ulative beings would yet discover that the
very cold water found BY Lieut.. Bergman.
as described in our last number, was melt
ed ice that had come from the Arctic re-
gions through this inner passage, aud had
oozed out near Bermuda. The hole through
the earth cannot account for these varia-
tons, as this theory must involve the ne
cessity of regular ocean current running
round and round, net ebbing and flowing.
Many persons-according 10 letters some
times received BY us-still seem to be much
perplexed with the phenomena of the tides.
They cannot understand why they are high
er at one time than another, nor why they
rise to the hight of sixty feet in the Bay of
Fundy; forty feet in the ports of Bristol.
England, and Malo, France, and only rise
to few feet in hight in New York and 9TH
er places, while they are scarcely percepti-
BILE in the Baltic and other seas. Descartes
was the first philosopher who advanced the
: theory that the tides were due to the inf1u-
enee of the moon, but Newton was the first
who worked out the problem, and discoy-
cred the true cause, Descartes believed
that the moon acted upon the waters of the
ocean by pressure; Newton demonstrated
that it acted upon the ocean 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 producing
the two tides every day. The tides are
caused by the attraction of both the moon
duO IhC oOh. Ai tuiS car I'll uo0 HO hAOOhs
the attraction of the sun would produce two
tides every day, but their ebb and flow
would take place regularly, not varying as
they do now; these tides would also be
much smaller than those of the moon
= Although the mass of the sun is far great
} er than that of the moon, and although at
l traction is in proportion to the mass, yet it
: is also inversely as the square of the dis
G ha c11n 10 fnTlr ha1O-
dred times farther distant than the moon,
} the attraction of the waters of the sea to-
| ward the sun is found to be about three times
less than that of the moon; the tides pro-
} duced by the sun would therefore be three
times less than those of the moon. There
are really two ocean tides, the lunar and So
lar, but the latter is absorbed By the former,
which is wholly observable in respect to
time, the solar only as it influences the
tidal wave. That caused by the moon fol-
lows its motion around the earth, rising and
falling every twelve hours, and each sue
cessive tide later By three quarters of an
hour than the preceding one, exactly in ac-
cordance with the positions of the moon,
or as it is commonly called, ''its rising and
setting"
Sometimes there are very low and at 9th
! er times very high tides. This is caused
by the positions of the sun and moon rel
! alive to the earth. Thus, at the time of the
new moon, the sun and moon being in the
, same part of the heavens, the tides are then
the highest, because they are equal to the
sum of the two tides-lunar and solar
This also takes place at the time of full
; moon, when our satellite is opposite the sun,
the attractive force being equal and oppo-
: site in producing the tidal wave. During
the first and last quarters of the moon, the
attraction of the sun not acting in unison
, with that of the moon, tends to lower the
tides.
Reasoning from this data, it viii natur-
: ally be inferred that when the sun and moon
are equally distant from the two poles of
the globe, such as at the times of the equi-
. noxes in March and September, the tides
would be the greatest. This is also found
to be the case, thus demonstrating beyond
all doubt that the fiux and refux of the sea
are due to the attraction of the sun and
moon upon its waters. The difference IN
/. the hight of the tides at various places is
due to the peculiar formation of sea coasts.
, They are very high in the Bay of Fundy,
, because an immense quantity of water is
piled into wide-mouthed narrow space, in
the same manner that certain quantity of
E water win rise higher in narrov than in
. wide channel. Some have advanced the
! popular belief agaenst the lunar influence
: causing tides. namely, that the Mediterra
mean IS tideless sea. This IS not strictly
true. The ocean tides. owing to the mar
row passage into the Mediterranean at Glib
! ralter, scarcely affect the sea; but Tor all
this there are regular tides observable at
; some places At Vienna they sometimes
rise to two feet and IN the Faro eff Messina
TO twenty Scientific ADserices.