Alpena weekly argus. [volume] (Alpena, Mich.) 1871-1893, 1880-08-04
Doom Sen EXPLORATIONS.

Deep sea Explorations.
Some very interesting results Of
recent deep sea explorations were
concisely stated in a late lecture at
the Royal Institution, London.
Nearly three-fourtbs of the surface
of the earth is covered by sea.
The average depth of the ocean is,
according TO the latest calculations
of Mr.. Otto Krummell, about
l,S76 fathoms, or somewhat over
two miles The greatest depth
known to exist was discovered by
the United States ship Tuscarora,
near the Kurlie islands, in the north
east Pacific. is 1865 fathoms, or
about five miles and a quarter.
The highest mountain existing is
about the same height as the deep
est sea is deep. Mount Everest is
1888 fathoms in height. So in
significant, however, is the total
volume of the land raised above
sea level in proportion to the vast
cavity occupied by the sea, that
were this cavity emptied of its
water, the whole of the land now
above sea level could be shoveled
into it twenty-five and a half times
over before it would be filled up
to the present sea level.
Nevertheless, the depth of the
oceans, great as it is, is nothing in
comparison with the vastness of
their extent of surface. As Mr..
Croll has said, the oceans in rela-
ton to their superficial area are as
shallow as a sheet of water 100
yards in diameter and only an inch
in depth. The sides of the ocean
basins are not at all steep. They
are mostly so little inclined that an
ordinary locomotive engine could
run up them in straight line with
ease. There inclination is not more
than three or four degrees or less.
Around some oceanic islands the
slope is greater. The steepest
slope know is at Bermuda, where
there is an inclination of nearly 20
degrees from the edge of the reef
to 1000 fathoms. There are no
such things as mountains and val
leys on the sea bottom. Animals
cannot slip down against their will
into the depths, but must move de-
liberately into them, and travel a
long journey to reach them. The
pressure exerted by the superin-
cumbent water at great depths il
so great as to be almost beyond
conception. 1t amounts roughly
to a ton on the square inch for
every 1000 fathoms of depth,
about 166 times as much as the
pressure to which people are sub
iected on land. AT the greatest
depths the pressure is about four
tons and half. Vast though the
pressure is, it is, which Professor
Abel and captain Noble have
measured, as produced in their
experiments on gunpowder. The
deep sea animals, being completely
permeated by fluids, are probably
no more conscious Of pressure act
ing upon them than we, and, so
long as they move slowly from one
depth to another, are most likely
unaffected by the consequent
changes of pressure.
With regard to the temperature
of the deep sea water, the condi'
tons which would affect animals
are comparatively simple. Nearly
all over the ocean the temperature
at 500 fathoms is as low as 40 de
grees f., and this is the case ever
Immediately under the equator il
the Atlantic and Pacific oceans
Below 1000 fathoms the tempera
ture is never more than a few de
grees above freezing point, except
ing in the peculiar cases Of land
locked seas, such as the Sulu Sea.