The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1871-04-12


The late deep sea researches of the English
government, under DR.. Carpenter, make one
OF the finest chapters Of physical science.
Since the Inauguration In this country many
years ago Of the system Of oceanic cxplora-
tons and the splendid results achieved the
European Powers have emulated our example,
and the fruit Of their labors is now apparent.
In attempting last summer to solve an old
problem of the Mediterranean inflowing cur
rent at Gibraltar, the English expedition, by
a series of the most accurate experiments from
the deck Of the Porcupine, not only accom-
pished their purpose, but also discovered the
law of the entire oceanic circulation.
Under the rays of a fiery sun, and exposed
to the drying, hot winds from Africa, the sur
face of the Mediterranean becomes a vast
evaporating dish, whose level is so rap
idly reduced that to supply the waste by
evaporation there must be an incessant
indraught OF Atlantic water. This latter Is
highly charged with salt, which is not taken
up by sun or wind, but precipitated; and
hence it was long ago argued by the philoso-
pher HALEY that there must be some escape
Of this salt from the bed Of ''the classic sea"
by submarine current. Careful and CON-
tinued exploration now demonstrates a fact
which the theory of HALEY and the close
reasoning of Maury had previously, and
against many eminent sceptics, suggested as
the only solution Of the Mediterranean
problem.
BY the double evidence Of specific gravity
and chemical analysis the English explorers
found an excess of salt in the waters of the
Mediterranean over that in the Atlantic; and
they found also that this excess is greater In
its bottom water than in water taken near tho
surface, while in the Atlantic the difference Is
in contrary direction.
BY suspcnding ''current drag" from boat
floating on tho inward and surface cur
rent near Gibraltar 1.-TWO sets of observations,
made at an interval of six weeks, giving iden-
teal results), although westerly wind com.
bined with the strong surface-drift to carry
the boat inward, the force of the under current
acting on the ''drag" at depth Of two
hundred and fifty athoms nearly suf-
feed to check its motion. In the second
trial, the wind being easterly, the boat
was carried out into the Atlantic against the
powerful stream in which it loated by the
invisible agency of current flowing more
than quarter of a mile beneath the surface.
If the waste by evaporation was restored to
the Mediterranean by an inflow of fresh water
the quantity Of salt in its basin would remain
the same. The upper current of saline Allan
tic water, bringing in Il quantity Of salt In
addition to that which the Mediterranean pre-
viously held, the density of its water is in
creased, and as DR.. Carpenter justly argues, q
column of it reaching to any given depth is
rendered heavier than an equivalent column
Of Atlantic water.
To illustrate the great discovery which has
been made by DR.. Carpenter in its bearing on
the whole oceanic circulation, we have only to
suppose, as he does, that the Mediterranean
water were made heavier than Atlantic water
by an intense Polar cold (instead Of, as now,
by evaporation), and we should still have
exactly the same currents as have been found
at Gibraltar.
For the Mediterranean cooled down subst-
Equatorial ocean, and there would necesss.
rily be constant Interchange between Polar
and Equatorial waters through the seas of the
temperate zone. Tho reduction in the tenn
perature Of the column Of water in the Polar
basin contracts its volume, lowering its level
while augmeating its density. Thus the water
of the surrounding area mus. flow in to main
tain the level lowered and when the Polar
column has been restored to an equality Of
| height 1t will have such an excess of weight
| that It's downward pressure forces out pOr-
!! ton Of its deeper water, causing an outflow Of
| ice-cod water over the deep sea-bed toward
| the Equator. Vertical circulation, Of course,
returns an equal quantity OF warmer surface
| water into the Polar basin. Such is resume
! of the highly interesting results reached bv
| one Of the most successful of modern expedi-
ions, and very recently made known by its
illustrious leader. They are not speculatlOns,
but facts that have been thus beq1eathed to
the science of the ocean. They were verified
in the deep channel between the Farce AID
the Shetland Islands, where Dr. Carpenter
found compressed but remarkable epitome
of this oceanic vertical circulation. The
whole under stratum OF water in this
channel, exceeding three hundred fathoms, or
nearly two thousand feet in depth, forms an
Arctic stream, having temperature Of thirty
degrees, and bringing with 1t the characteris'
tic animals Of Iceland, Greenland and Spitz-
| bergen; while, on the other hand, the warm
stratum Of surface water everything the cold
water three hundred and fifty fathoms deep
moves in a northeasterly direction and fulfls
lis mission In keeping up the level and ame-
| liorating the climate Of the Polar area.
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