Evening star., 1907-10-19

there is a continuous lowering of the
strand line.
The theory that the earth was originally
q tetrahedron was dismissed by DR.. See
as not even a plausible delusion. Even
were our planet as stiff as steel and given
tetrahedral form. the corners. he said.
would be crushed down and the figure
rapidly rounded up under its own attrac-
ton. A column of the stiffest granite or
steel would not stand over five miles high
without crushing or vaporizing at the
base. and a solid pyramid, such as would
form the corners of a tetrahedron. could
attain no vast height before 1t would
begin to spread at the base and flow from
it's own weight. even II formed of the
hardest material. There is thus a limit to
the height at which even mountains
could stand. although this seems never
to have been attained by mountains on
earth.
Moon Left Earth.
The separation Of the moon from the
earth caused our principal ocean basins
to form. 1t cannot be said at what stage
the moon parted company with its parent
earth. nor how much larger in volume the
earth then was than ii Is now: but the
separation probably took place before
the crust of the earth commenced to FORM
and 1t probably originated under the dis
turblng action OF the solar tides The
detached mass seems to have come
mainly from the protuberances on the soft
earth drawn out by the suns attraction
and lying toward and from the sun The
Pacific. Indian and Atlantic oceans prob
ably represent the holes left by the dis
ruption, the first two named being evil
IDENTIFY the area from which the matter of
the moon was mainly derived. The in
eQualities remaining after certain masses
had again united with the earth prob
ably gave the foundations on which the
continents have since been built There
was some modification and remodeing
also by the suns draw upon the molten or
thinly encrusted earth-i. e., by the solar
| tides But all smaller inequalities occur
ring since the earth's crust hardened
all mountains, high plateaus and deep
ocean troughs-have been produced mainly
by earthquakes due to steam from the
| leaking oceans and not to any continuous
shrinking of the earth.
Only 100000 Years Old.
The earth is about 10. 600 900 years old
! by no means so old as many biologists
have been inclined to believe. according
to DIR. See. This he calculates by use of
formula. the exact figures being S302, 900
/ years since the crust OF the earth con-
solidated. which is supposed to have oc-
! Cured very soon after the first begin
nings of the spheres formation. Lord
! Kelvin, after assuming that the greatest
| temperature on the surface OF the earth In
past ages was 1000 degrees Fahrenheit,
similarly calculated the age Of the earth
| to be 1O1. .6I3. 600 years. but DR.. See as
sumes that this temperature on the sur
| face never could have been above 1000
degrees F'aS- enheit. DR.. See further esti-
mates tnat the Andes might have been
| formed In some thing like 100000 years.
| and the plateaus west OF the Rockies in
not more than 100000 years. The cool
| ing of the earth has nowhere extended
| below forty miles, or one-one -hundredth
of the earth's radius. and has been con-
| fined almost entirely to the crust, accord
| ing to the astronomer
JOHN ELFRETH WATKINS.