The morning news. [volume] (Savannah, Ga.) 1887-1900, 1895-06-06

to provide the energy by which the tides
DO their work. This, however, is not exactly
the case.
The match which lights the fire under a
steam boiler is in one sense no doubt the
cause OF the energy developed. but we do
not therefore assert that the power of the
engine is derived from the match. 1t comes
rather from the fuel whose consumption
IS started by the match. In like manner,
though the moons attraction causes the
tides, yet it is not from the moon that the
tide energy Is drawn. There is only one
possible source for the energy necessary
to sustain the tides. Every one who is
cOnVersant with mechanical matters
knows the important duty which the fly
wheel performs in a mill. The fly wheel
IN fact, may be considered as a reservoir
INTO which, the engine pours the power
generated with each stroke of the piston,
while the machinery in the mill draws
on this accumulated store of power in the
fly wheel. If the engine is stopped the fly
Whel may yet give a turn or two, for the
energy which IL contains may be still suf-
ncicnt to drive for a few seconds the ma
chinery through the mill. But the store
OF energy in the fly wheel would neces-
sarily become speedily exhausted and the
ny wheel come to rest unless II were re-
plenshed continually by the engine.
The earth may be regarded as a mighty
fly wheel which contains a prodgious
store OF energy. That energy is, however.
never added to, for there is no engine avail
able. If, however, no energy were with
drawn from the earth, then the globe
would continue to spin around its axis
once very twenty-four hours forever. AS,
however, the tides need energy to get
through their work thy abstract what
they require from the store which they
find at hand in the rotation of the earth.
Next time you see the tides securing up
and down river you may reflect that the
power which impcls that mass of water
to and fro has been obtained solely at the
expense Of the spinning of our globe In
deed, the little child who digs a moat in
the sand which is filed by the rising tide
Affects to a certain extent the revolution
of this earth about its axis.
This withdrawal Of energy from tbe
earth Is necessarily taking place along
almost every coast. From day to day
from century to century. from aeon 10
aeon, energy is being withdrawn and
wasted, never again to be restored AS
the earth has no other Tnkans of replenish-
ing Its stores, the, consequence is inevi-
table; The quantity of energy due to the
rotation of the earth must be gradually
declining. Stated in this way perhaps the
animation Is not very alarming, but placed
IN other words the results at which we
have arrived assume the more practical
expression that the times must be grad
ually checking the speed with which the
eearth turns round. The tides must. i'm fact,
be increasing the length of the day. In
consequence of the tides which ripple to
and FRO on our shores, and which flow in
and flow out of our estuaries and rivers
to-day IS longer than yesterday and yes
terday Is longer than the day before. l
may, however admit at once that the
change thus produced is not very appre-
cable when only moderate periods of time
are considered. Indeed, the alteration in
the length of the day from this cause
amounts 10 no more than a fraction of
second in a period of a thousand years
Even in the lapse of ordinary history there
Is no recognizable change in the length of
the day. But the importance of our argu-
ment is hardly affected by the circum-
stance that the rate al which the day is
lengthening is very slow one. The
really significant point is that this change
ala It, al
in the same direction.
1t is this latter circumstance which gives
TO the present doctrine its great impor-
lance as a factor in the development of
the earth-moon system. We are accus-
toned in astrunOmyito reason5about move
ments which advance for vast periods in
one direction, and then become reversed.
Such movements as this, however, are not
the real architects of the universe, for that
which Is done during one cycle of years
Is undone during the next But the tides
are ever IN operation and their influence
tends ever in the same direction. Conse-
quently the alteration in the length of the
day Is continually in progress, and in the
course OF illimitable ages its effects &C
cumulate to startling magnitude.
The earth now revovles on its axis once
IN tWenty-tour hours. There was a time
inlllilons OF years ago, very likely, when
Its reVolVed once in tWenty-three hours
Earlier still II mast have spun on its axis
IN twenty-five hours, while this succeeded
uIne when the day was only twenty
piled in those times which apply at the
present, so that, if we strain our vision
pack INTO the excessively remote past we
nhu the earth spinning ever more ana
more rapidly, until at last we discern an
epoch when the length of the day was
something like five or six hours. This is
mences. At this eventful period the earth
accomplished about four revolutions In
the same time that it now requires for
a single one. We do not attempt to as
sign the antiquity of this critical mo-
ment. II must certainly have been far
carrier than the time when this earth
pecdine utted for the reception of organ
lzeq lie. 1t must have been at least many
nlillons OF years ago. If ii be thought
Ihat the Vagueness of our chronology is
rather unSa tSfactory, then it must be re-
membered that even historians who have
human records and monuments to guide
lhem, are still often in utter uncertainty
empires hourished, or as to the dates az
winch great dynasties rose or persisted
but our story has another side to It,
among the profoundest laws of nature is
tilat winch asserts that action and reac-
ton are equal and opposite, We have seen
Inat the moon is the cause of the tides
as brake to check the speed with which !
the earth is rotating. This is the action
OF the moon upon the earth, and now let
US CONSIDER the reaction with which this !
acuon must inevitably be accompanied.
IN our ordinary experience we observe
that a man who is annoyed by another
annoying agent away as far as possible. I
This IS exactly the form which the reac- /
ton of the earth assumes 1t is ANNOYED /
by the moon, and accordingly ii strives
10 push Che moon away. Just as the moon /
by It's action on the earth through the me- /
dunn of the tides tends to check the |
speed with which the earth is rotating on |
Its axis, so the earth reacts on the moon.
ana compels the satellite to adopt a con- /
tinuous retreat.
The moon is. therefore, gradually reced- |
ing. 1t is further from the earth to-day |
than 1t was yesterday; 1t will be further |
tomorrow than it is to-day. The process /
Is never reYersed;it never even ceases. The !
consequence is a continuous growth in the /
size of the track which the moon describes |
growth is a slow one. so, too the growth /
of the oak is imperceptible from day 10 /
day, though in the lapse of centuries The !
enlargement of the moons orbit. though