New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1886-09-25
TIDES, EARTHQUAKES AND VOLCA-
NOES
ARE THEY ALIKE CAUSED BY PLANETARY
ATTRACTION


To the Edftor Of The tribune
SIR Imagine globe thirteen feet in diameter filed
with liquid hot matter and with solid crust only
inch Thick and it would represent. compare
lively. the earth with It's fifty miles Of crust and
nearly eight thousand miles Of interior. 1t Is WELL
known fact that heat increases the deeper descend
into the earth. This has been ascertaned by actual
experiment In deep mines, and this increase Of one
degree in temperature for every fifty feet In depth
would produce heat twenty-eght miles down that
would melt every known substance. Therefore the
probabilities are that the crust is less rather than
more than fifty miles in thickness. Professor Ball
says - few feet of brickwork will so keep in the
heat of mighty blast furnace that but little will
escape Cannot then, few miles of rock nearly
mask the heat in the depths of the EARTH though
that heat times hotter than the mightiest
blast furnace that ever eIistedi"
Suppose had a bail of substance more elastic
than rubber. Fastcn a cord to it, and taking hold of
the o.her end of the cord whrl it around rapidly We
can readily understand that account of its elasticity
and by of the two opposing forces tb of the
cord and the centrifugal force pulling at the same
time it would lengthen out in direction and
narrow correspondingly in the other Thus it is with
the tides The earth is not whrled rapidly around
the moon, but precisely the same effect is produced
The moons attraction Ia a constant pull on the earth
the same d5 t1e cOru on the elastlc suOslancc auu
the earth's velocity of than thousand miles
minute on its journey around the sun, produces an
opposing pull corresponding the centrifugal force
acting the elastic body the end of the cord and
between the two forces the earth has powerful
tendency eloDgate the had the elastic body;
aud the oceans by of their physical condition
being able respond the result is tides on the
two sides of the earth which opposite to each
other and in a direct line with the moon.
But we should not overlook the fact that as there
is water on the surface few miles deep, there is also
a vast liquid inside Of the earth nearly eight
Thousand miles deep, which must be equally elastic
and able to respond and by the law OF gravity must
respond to the two forces in the and in
the same direction the surface tides. This mass of
liquid matter by of its immensely must exert
an enormous outward pressure on the inner side OF
tho earths crust its tendency to elongate Now
we will suppose in the motion of the bodies of the
solar system a time comes when the sun and or
two of the larger planets come IN direct line with
the and earth which was the case at the time OF
the Charleston shock, 1t being Jupiter then, the
largest of all the planets. The result would be an
additional attraction; the tendency OF the immense
molten mass within the earth to eongate would be
augmented and its outward pressure correspondlngly
ased. 1t might be sufficient to overcome the
resistance of the earths crust in a weak part, and
there would then be earthquake. But the velocity
OF the earth its axis great that the weak art
in its crust would be rapidly carried away from The
strain aud the pressure cOcrespondiDgly diminished
In about twenty -four hours, however the earth
would be nearly in the same position again, and
another slight shock would probably be felt in the
same weakened part. But as the moon is continually
changing its position, it would be somewhat out OF
line with the other bodies and this difference would
increase from day day and the strain correspond
ingly decrease This condition of things, VIZ, the
same position of the earth In con- junction with the
moon sun and a large planet, might not occur again
for thousand years, and the liability OF repetition
oil the disturbance the point TOR some time TO
come would he very slight.
II we 90 b.ck to a time when the earths crust was
withstand the grea, pressure of these internal tides
and was continually bursting outward IN one dlrec-
ton and inward IN the other as the earth turned on
its axis THIS continued tor ages, but as the earth
went on cooling there came a time when the crust
became sufficiently thick Withstand the strain and
the internal burst through only IN such places
as had continued weak by their occasional action,
and the phenomena of volcanoes was produced.
Ice forms on still wafer with uniform thickness
But when in high water pressure it is brokep up It's
surface becomes Suppose the reeZlng still TO
continue, after time 1t Is again broken up; its
surface would become still more uneven, and there
would be little mountains, hills and valleys. mus II
this frequent breaking up during past ages caused by
the internal tides different points and at different
times the surface of the earth would now be as
smooth and a the surface OF lake on q calm
summers day. We would have hills. no valleys.
nothing III any direction but vast unbroken plain
We are indebted these internal tides for our seas
lakes and rivers for lives, Tor without these
earth would now be perfectly smooth and the oceans
would spread out and envelope the whole earth aud
there would be no land. w. H. Jay.
AeiC- York, Sept. II, 1856.