Polynesian., 1856-12-06
The recent SOunaings for Ghe Atlantic Tel.
egraph.

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egraph.
| On application being made TO the American CO.
vernment they, with most laudable zeal for the
promotion Of this great national work, expressed
their readiness to render to the projectors of the
Atlantic Telegraph every possible assistance and
the Secretary of the United States Navy, Mr. Doh
bn courteousIy placed at their disposal the Arai,
the vessel most fitted for the purpose, and seec-
ton of officers whose known talents and experience
in this particular department of nautical science
leaves nothing to be desired Lieut.. Bergman,
who had already once taken soundngS across the
Atlantic, was appointed to command this expedition,
with the object Of repeating and enlarging his fer
mer observations Lieut.. Strain whose zeal and
energy IN command Of the perous Darien Expe-
dlton, well his love for, and attaiuiner:s in
science, qualified him for his office and NJ :,ltch-
ell, acting master, who had accompan.,U Lieut..
Bergman on the former occasion these, with
full complement of other officers, and men special
y chosen for the purpose, have done their work no
bly,. All, from the highest to the lowest, have
thrown their hearts fully into the work, and it has
indeed been well dOne-cven those OF the seamen
who should have been below, have been seen creep
inc from their hammocks at midnight, to watch the
return Of the lead, and 10 learn the result in some
of the deepest soundIngs. The track thus subject
cd TO repeated and critical survey, extends from ST.
Johns, Newfoundland, 10 Valencia Bay, at the
southwestern extremity Of iceland, distance Of
$40 nautical, or 900 statute miles.
Within these limits, on Course corresponding to
the line of the grCat-cIrce sailing, soundings have
been taken at intervals of about thirty miles, and in
each instance (by means Of quilts affixed to the
bottom of the sounding apparatns) i sample or
specimen Of the ocean bed has been obtained.
These samples are now undergoing close micro
scoplcGl examination but even the first cursOTy
glance disclosed an abundance of the most fragile
forms of she'll, either of recent Of fossil iufuso
ria, so delicate, and yet so perfect as to afford
-
movement of the water at these great depths thus
confirming in the most satisfactory manner the re,
suits of the previous soundingS. Not single rock
has been met with, not particle of gravel or sand
has been brought up, but it appears as if nature
had provided bed I" soft 4 snowbank," to use
Maury's own words, for the express purpose Cf re-
celving tclegraphic cable.
Lieut.. Bergman says that he is satisfied that the
lead, with the sounding apparatus, has frequently
buried itself ten or fifteen feet deep in this soft ma
teria and he doubts not that the cable will likewise
sink, and imbed itself in a similar manner. The
greatest depth attained has been two thousand and
seventy fathoms (abOut two and one third mies0
but perhlps the most remarkable, and at the same
time the satisfactory result, is the perfect con-
frmation which these soundingS give of the opin-
ion expressed by Lieut.. MauTy, as to the existence
of great fiat or level at the bottom Of the ocean,
unparalleled by anything the surface of the earth,
and which he proposed TO name g The Telegraph
Plateau" For more than thirteen hundred miles
the bed of the Atlantic, in the direct line of our
track. Is found by these soundings to present an al
most unbroken level plain. Nature has thus placed
no obstacle in the way of this great undertaking,
which may not by cautious perseverance, be over
come; nay, rather IF except the enormous
length of cable which will be required,) it would
seem that the line to be followed by the Atlantic
cable presents absolutely fewer engineering diff
cultics than the shorter route (thongh more COM
Ms tho off no hptt yVb
Mediterranean cable must be laid.
The vessel being - hove to- and made to re-
main as stationary possible, the lead is dropped
into the water from pulley on the fore-yard arm.
and carries with it the line, which in its Descent
it raridIy unwnds from the large reel. The de-
scent at first very rapid, gradually dlmlnishes IN
speed, in consequence, not of the enormously IN
creased density ofthe water rs usually supposed,
but of the gradually yincrcasing friction due to the
Ienrth of line drawn through the water. This dim
mutton of speed at different depths has been ac-
curately notrd by Lieut.. Bergman, and Is remark
ably uniform. The descent III the deeper sOand-
ings usually occupied about three hours. The ar
of the mechanism is such, that the mo-
ment the rod carrying the quiIls touches the bot
tom the wires, which were previously supported
hy hooks become detached, aud allow the escape
of the lead; while the qus and the register
which are attached to the rod thus relieved of It's
load, are more easily drawn up again Still tho
process OF raising, though tacilitated by discard
inr the leaden weight lof 90 lbs. TO 10 lbsl
would be tedious and laboriouS for human hands
There is, therefore, small s;eam-engine attached
to tie reel, having two Osciating cylinders, whose
piston rods work direct upon a crank on the axle
of the reel; by this means the raising Of the ap-
plratus occupies less time than its descent SulI
it Is a slow process, and occasionally, from the
currence of knot twist IN the line, 1t has heea
snapped at the pulley when nearly raised, and iIo
whole labor Of the sounding, together with the
apparatus and specimens, have been lost.-H6ts-
,rGted London NerS.
The wrappinGs OF The MumEnies-