The Placer herald., 1856-01-12
Supposed Causes of the Open Polar Sea.

Datus Kelly, correspondent OF the Com
merciol Register, (Sandusky, Ohio,) writes
in that paper of date November 23d as fol-
fows:
There are many persons who think it al
most incredible that an ocean free from ice
can exist around the North Pole: and see no
cause to produce this effect. The causes that
produce this open sea are easily understood,
and which | will endeavor TO give. A few
facts require to be given, that the reader may
better understand the premises, from which
my conclusions will be drawn.
In the first place, water attains its greatest
density at 40 deg. Of Fahrenheit, and ex-
pands as it grows warmer or colder. TO be
more perfectly understood by all your read
ers, will illustrate the principle further
Take any amount of water--say ten pounds
place good thermometer in it, and when it
is stationary at 40 deg it will be found to
take up less space or room in the vessel that
holds the water than when it is either warm
er or colder Cd. Fresh water freezes at 80
deg. and ocean water at about % l2 deg.
Sd. In the Atlantic Ocean the surface of the
water attains its greatest density, or takes up
the least space in proportion to its weight,
from the Island of Newfoundland to the
coast Of Norway, varying little to The north
or south, as the cold or warm seasons predo-
inmate. The Gulf Stream here meets the
cold water, with the vast icebergs from the
polar regions; these two opposite currents
mmge together and produce the tempera-
ture of 40 deg. These are well known facts
to all persons acquainted with geography
and chemistry. The water, after comming
ling, sinks, for the very plain reason that it
is heavier than the water either north or
south of it. This water, as it sinks, forms
two under-currents-one running towards
the equator. and the other towaads the pole
HE different temperatures in the air in
two adjoining rooms in house, beautifully
illustrates the principle am seeking to prove:
open a door from a warm room into a cold |
one, and Immediately a current Of cold air
will rush through the doorway, at the bot
tom from the cold room; and warm and
lighter current will pass rapidly out of the
warm room, at the upper part of the door
way. into the cold room. This will continue
until an equilibrium is produced in the tenn
pcrature of each room. This experiment can
be tested bv any one, by holding candle
in the upper and lower parts of the doorway,
and observe the direction in which the can
die will flare The same principle holds
good with water The heaviest water will
run under the lightest Except when violently
a@tated) whether made lighter by heat or
cod. and will continue to do so until an
luiibrium is produced. This can never be,
so long as Il torrid, a temperate, and frigid
temperate of the atmosphere continue to in
iluence the water in the ocean--but the
same unccaslnG currents must forever flow.
These principles extend to both oceans and
to both hemisphcres, as far as the shape of
the land in each hemisphere corresponds to
the other.
The under current, running north, rs 1t
enters the Polar Sea grows colder and light
cr, and Of necessity rises to the surface. This
current then becomes a Surtace current, car
rying with it, as it leaves the polar basin,
the immense masses Of Ice to the South,
until it meets the warm currents from the
equatorial regions, where it again attains
the temperature of 40 deg. and again sinks
from its increased density,-thus performing
another revolution to the pole and back.
AS the water in the ocean, from Newfound-
land to Norway, is heavier than the water
either North or South, it Of necessity must
be iower at its surtacc (Which is easily prov
ed by eXperimcnt) thus causing the surface
currents from either direction to run from
higher to lower level-or, in common par
lance to 1un darn hill.
1t is well known that the evaporation Of
water is greater, in Just the proportion that
the atmosphere is colder than the water; and
that the water necessarily loses IFS heat in
the same proportion. The intense cold in
the polar regions, in winter causes much
greater loss Of heat, rendering the surface
water colder and lighter than in the summer
season. this gives force to larger and stron-
ger under current, to set into the polar basin,
and corresponding surface current running
from it, in the winter season. This last
statement is proved from the great difference
there is in the quantity of ice that is thrown
from the North, at different seasons Of the
year.
The difference Of temperature of ocean
water, from its greatest density at 40 deg. to
the freezing point at % l2 deg, is | l 10.
| This difference is sufficient to allow of the
water to extend enough to rise at and near
the pole, several degrees above the freezing
point, and to run in circular direction to
the SO deg at all seasons Of the year, before
it reaches the freezing point.