The National tribune. [volume] (Washington, D.C.) 1877-1917, 1895-09-05
FAIR Lung.
Influence of the Moon in Terrestrial
Affairs.
BY LIEUT. LOUIS f. BOUTWELL,, sT
Concluded from last sOeek
III.
TIE GENESIS OF TIDES.

TIE GENESIS OF TIDES
Were there no other conditions than these
two opposing forces-the one trying 10 fatten
out the other striving to maintain a spherical
form--the zone of water heaped up in the
equatorial region would, as we have seen, soon
come TO stable equilibrium, and, attaining a
hight compatible with the two forces, would
he sustained. Suppose such to be the case-ss
would be if the world we're absolutely alone in
space. suddenly new body, more than one
fftieth times as massive rs the earth aud
equipped with the eternal spirit Of gravity,
springs into existence aud dashes past the earth
less than $50 600 miles away. No one can i'm
neine that they would remain indifferent TO
each others proximity. OF one accord they
would hurl forth their unerring lariat of
gravity. There would be jar. a wrench, and
recoil. Then the earth would whirl the
weaker body into orbit and swing back into
ats accustomed course.
Bat there would be a change. The moons
cast could not utterly fail. If its mass could
not pull the earth il could give all its power
10 the strsinlng centrifugal force, and for the
instant overcome the eartb's gravity. The
waters OF the sea, and the ocean OF air IS well,
torn into new commissions by the united
strength OF these two forces, would spring to-
ward that part of the earth where the new
force acted perpendicularly. Here the water,
Srawn from all sides, would rear still higher
Nbe equatorial crest until new balance OF
orces was assumed. Then the newborn tidal
wave, like the immortal Passepartout, would
follow the new master in his journey around
the world.
This is not all. Not only would the seas rise
toward the moon, but the earth itself must
yield trine. But since a rigid body attracts
or is attracted If its at its center
Claw OF the center Of gravity, the earth is, to
ali effects, 1900 miles from its surface. Hence,
IN fltp 10 If lat ion lp nf
gravity would be considerably decreased before
it affected the solid earth: then, the mass of
the earth would be drawn considerably less to
one side than the fluid at its surface nearest
the moon, but, according TO the same law, con-
sderaby more than the fluid at its surface
farthest from the moon, which would be 1000
miles farther away.
In other words, the mass Of the earth, con-
sidered al its center Of gravity, is midway be-
tween these opposite superficial points. and
will, therefore, in consequence OF the moons
influence take position midway between the
places most affected aud the one least affected,
thus giving the appearance of two elevations OF
water on opposite sides of the earth; and these
two crests. if unhndered, travel around the
earth every lunar day, the apex of each half
of %. 600 miles behind the other.
This, in theory, would be the effect Of the
gravitation Of the moon upon the earth. The
sun would have the same general effect, though
IN dlUerenB degree. Inc greater distortion
that would result from the greater mass of the
sun would be more than counteracted by the
S2,OOO,O0O oil miles that stretch between US and
fiery neigbbor. Although the sun is
Sc, 100000 times larger than the moon, its at
tracing force upon the earth is much less than
half as much, and so becomes a modifying in
huence upon the more pronounced effect Of the
moon.
So far in this paper the land masses have
been disregarded and as their effect upon the
tidal wave will be considered in another chap
ter, IL viii perhaps be unwise to complicate
matters with their introduction here. Hence,
we are free 10 imagine world entirely covered
with water, as perhaps our own was before the
first Laurentian rock lifted its jagged breast
above the waves.
The two tidal waves then, knowing neither
birth nor death, would flow endlessly around
the earth from east TO west. There would be
only slight difference perhaps between high
and low tide. There would be no races no
bores, no m@lstroms. There would be only the
changed.
Yet not unchanged. There comes a time
when the moon and sun act together. They
are either in conjunction or opposition. Then
the waters rise higher. though there be no eve
TO see, no shore to record the change in its
sandy beach.
Slowly the moon swings into ouadrature and
deep Now the sun, of at right angles makes
his strongest effort 20 pull down the moons
tidal wave and erect one OF his own. lie half
succeeds. Then, falling back. the king of day
and the queen of night once more dwell and
reign Tor brief period in peace. So end
leEsly, and man, coming into the field untold
ages after, found the changes still going on.
And he gave name to the each extreme and
bis English-spcak children know the highest
as the spring tide and the lowest, two weeks
later, as the nesp tide.
The tides then. are, first only a rational
effect TO attribute to the action of the force Of
gravity and such effect as we not only /
might expect to find but must find from the /
relation OF the co-aeting forces; and second. |
the remarkable regularity with which they
follow every phase and motion OF the moon
afford proof OF the lunar theory that zone can
dispute.
Finally, when we find the theory mistaken
by scientific and non-scientifc research. and see
how weak aud erring are all attempts TO over
throw IT, we awaken to the marvellous ma.
chinery IT involves and 10 the infinite genius
OF lis Inventor and engineer