Perth Amboy evening news., 1922-08-04
geographic News
Bulletins BY the
National Geographic Society
SEA BOTTOM

Explorers and g~eographers who
have been signing for new lands to
conquer may find their best field of
endeavor. paradoxically, in the sea.
Now that the United States navy
a perfected a device for measur--
ing the depths Of water by sound
waves without going through the te-
dious process of lowering sounding
lines 1t should be possible to add
greatly to the relatively little we
know about the underwater portion
OF the earth. The Importance of
this little explored region is brought
out In the following bulletin issued
from the Washington, d. c., head
quarters OF the National Geographic
Society:
When It is realized that nearly
three-fourths of the surface Of the
globe consists of water it is rather
remarkable how little we know Of
the vast surface Of the solid sphere
which lies under this screen of liq-
uid. The greater portions Of our
continents are mapped even to the
smallest details. n our harbors
n the shallow waters closely off
shore are fairly well charted; but
once the edges of the continental
shelves are passed the features of
the sea bottom are represented only
by a few somewhat vague contour
lines laid down between rather in
frequent points of soundings.
Not Sure of Greatest Depth
1--WE know without doubt that the
highest point on the earth is the
peak Of Mt. Everest which extends
above sea level for 29,002 feet-or
So feet less than five and one-half
miles. On the other hand we can
only speak Of the deepest abyss
yet discovered for one great pit,
hidden in the depths of the ocean,
has scarcely established it's title to
first place in recent years when it
has been surpassed by a deeper one;
and it can hardly be believed that
the deepest of all has yet been dis
covered.
school children were taught a
few years & that the deepest de-
preston in the earth's surface was
near the Fiji Islands and that it was
30.13S feet deep. Since then the
deepest holc on earth has been suc-
cessively Kermadec Deep. northeast
of New Zealand, 5000 feet. Nero
Deep, southeast of Guam. 31,616
feet, and the present holder of the
record, Philippine Deep. east of
the Philippine Islands, 32,0S9 feet.
This greatest known depth there
fore lies six miles and 400 feet below
the surface Of the sea.
Like Scratch on Billiard Ball
"The greatest range vertically of
the earth's surface is between the
bottom of Philippine Deep and the
top Of Mt. Everest, a distance of
approximately 11.6 miles. This
seems a tremendous distance until
it is compared with the diameter
of the earth which, near the lati-l
tudes of these great physical feat
ures, is approximately 5000 miles.
On a globe with a diameter Of eight
inches instead Of 5000 miles, this
maximum range of depression and
heights would be represented by a
scratch little more than a hun
dredth Of an inch deep. The
smallest division on a household
ruler is one-sixteenth Of an inch.
The scratch would be less than a
fifth of such a division in depth. On
a billiard ball one could hardly
scratch lightly enough with a pin
to represent the great Philippine
Deep, and a few grains of talcum
powder would stand for Mt. Everest.
The smoothest orange that grows
has much greater Irregularities on
it's skin in proportion to its size than
those given to the earth by all its
peaks and valleys.
Zone who studies the earth comes
to realize that in a sense the con-
tinents are subordinate to the great
ocean basins. The total volume OF
these depressions below sea level is
many times greater than the vol
ume of the land that rise above the
sea. If the entire land surface were
leveled down an nearly two
miles deep would sweep over ev-
cry square foot OF the surface OF the
globe. The condition of the CONT
nents nigh. at first glance be con-
sidered precarious. but dry land has
formed a considerable part of the
surface Of the earth for millions OF
a and will probably remain for
a long time to come. 1t has been
estimated that less than four cubic
miles of solid material is carried
into the sea by water annually. At
this rate, leaving out of considera-
ton upheavals and subsidences u
to earthquakes and other causes: IT
would require more than 6,O00,Ooo
years for all the present land to De
vvosbAN tuto the sea"