The herald., 1898-03-13

plausible theory does not take into ac-
count the fact that some Of these gyratory
currents are merely superficial being
crossed at various depths and angles by
extensive currents moving far below the
surface. The general course of these deep
currents is from the poles to the equator,
the South polar deep current being the
more pronounced on account Of having
wider scope and freer play.
THE COLD SUBMERGED CURRENTS
The operation of these submerged polar
currents is easily explained: Cold water
sinks to the bottom, and per contra, warm
water rises to the top. The melting
glaciers Of the Antartic continent are con-
stantly supplying immense quantities of
ice-cold water, which sinks into the deep
troughs of both the great oceans, and
creeps in steady, persistent tide toward
the equatorial regions where, becoming
warmed, 1t rises to the surface and thence
flows back again superficially toward the
poles.
DIFFICULT TO TRACE
While continuous current has been
mentioned, flowing from the coast of Peru
through devious windings till it is lost
in a dying swirl near the Aleutian islands,
the statement needs modification. The
ocean stream is not like river which
flows with uniform velocity between clear
ly defined banks. Some of the currents
are. in fact, quite difficult to trace. Each
of the equatorial currents are compara-
lively slow, and in some parts sluggish.
Then, again, the borders of the currents
blend imperceptibly with the adjacent
still waters. Finally, at their eastern and
western eXtremities they seem in doubt. at
times, whether to proceed around the next
curve or to turn upon thmselves; and a
violent storm has been known to produce
the latter effect.
The tendency of the currents to divide
is apparent throughout the system. While
the greater portion of the Peru current
joins the south equatorial, a small part Of
it curls back upon the coast at the isthmus
and another part turns southwestward to-
wards Australia. The south equatorial
sends one prong past the island of Borneo
into the Indian ocean, while the other
forms the north equatorial current.
We have already seen how the Japan
current sends one branch to Behring strait
and another to Alaska, while the main
stream becomes the southward-flowing
California current. When the latter
reaches the islands off Los Angeles the
main tide turns west into the Tropic of
Cancer current, but small branch con-
tinues down the coast till 1t meets the
northward-flowi equatorial current. OF
course 1t has been very difficult for ge-
ographers, navigators and physicists to un-
tangle all these facts and imperfect data
and construct from them a true and con-
sistent system.
VELOCITY
The velocity of these ocean streams va
ries from three miles an hour off the coast
of Japan to the same number of miles per
day in other localities. The gulf stream as
1t issues through Florida strait flows with
the extraordinary velocity of five miles
per hour. 1t is not surprising that a vol
| ume of water hundred times greater than
the Mississippi at it's mouth, discharging
its mighty flood upon the shores of western
Europe should have potent effect in ame-
liorating the climate of that continent.
Nor Is 1t surprising to the physicist that
the still greater volume of the Kuro Shiwo,
or "black tide of Japan, which pours its
vast floods upon the west coast Of North
America, should likewise exert a tremen-
dous influence in modifying the climate Of
that region and rendering 1t one OF the
most delightful sections of the habitable
globe.
The deepest portion of the Pacific ocean
is in the Japan current where 1t is the
swiftest. The ocean bottom at that place
is veritable cleft in the earth. 2S. 200 feet
(about five and one-third miles) below sea
level. This is the lowest point yet sounded
in any ocean. 1t Is curious to note in this
connection that the highest elevation on
the globe, Mount Everest, Is in the adja-
cent country, on the border of the Chinese
empire. That peak is $1,000 feet, or five
and half miles. above sea level, so that
the vertical difference between the summit
of Everest and the bottom Of Kuro Shiwo
is nearly eleven miles, or 1-730th Of the
earth's diameter. WIN. H. KNIGHT.
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