New Orleans Republican. [volume] (New Orleans, La) 1867-1878, 1875-12-05
Deep sen soEudings in the lsaIf.

|
attaches to those branches specially organ
ized TO extend the domain OF science. Tn
mi ghty energies evol.e by our late civi
war ind appropriate vent in government
| expeditions 10 explore the unfamiliar por
tons OF the continent. Equally if no
more interesting are the operations of TN
coast survey, which is fast making us Al
familiar with the bottom OF the ocean neare
Us as We are now with the land.
| The coast survey steamer Blake, Iieuten
| ant Commander {. d, Sigsbv, United State.
| navy, commanding. has been lying for som,
time at the Brookly navy yard. and having
been thoroughly supplied and reftted
started On Tuesday, the ninth ultimo. t,
complete the series OF soundings in the Gull
OF Mexico. On Saturday reporter and al
| artist of the'GrGphic visited the Blake and
spent d delightful day in the duty of IN
official inspection.
| he Blake was occupied last winter ia
| the preliminary soundings of the Cult. The
results arrived at are both interesting and
| valuable. The first work was to run radial
lines OF soundings from the month of the
| Mississippi some 80 miles seaward, to de
| termile the slope OF the delta-or rather
that part of the deposit which is vet under
water and being built up into delta. The
bottom was found TO he regularly uudulat-
Ing, the undulst;ons being slight and the
slope steady for most of the distance
sounded. The deepest water was finally
reached at point 10 miles out. southeast
from the mouth of South Pass, the depth
there being 1852 tathoms. On other lines
extending from tie mouths OF other passes
the regular slope ceased at a depth of from
liOO TO BOO isthoms. In the line run
southwest from Southwest Pass was found
the only abrupt irreguarity of the bottom,
For thirty miles out from the pass the
water continued shoal, measuring no
1nere than seventy-one fathoms: there
il deepened suddenly TO 2l5 fathoms.
Inns depth was maintained quite regu-
larry Tor about fifteen miles, when the
water suddenly sboaied again to seventy.
two tathoms; then more gradually to sixty
one tathoms, and beyond that deepened
regularly TO the end of the line The eur.
rents in that region set generally to the
westward till in April, after which they
changed slowly to the eastward, In Nav a
line was run from the mouth of Southwest
Pass to the mouth OF the Rio Grande, the
deepest soundiugs on thatEline being 300
tathoins. The latter part of that month the
Blake finished the largest line of soundiny s,
from the Rio Grande due east to Tortura
distance of about 7tU miles. The water
deepeIed very slowly for forty miles from
the Rio Grande. reaching only 100 fathoms
at that distance, then rapidly, and at a lit.
tie less than 100 miles out the sound was
les. But at even 100 miles a sharp ridge
was found upon the bottom, and there the
sounding was but S39 tathom=. This was
the most noticeable popularity of the bot
tom on that line. The rest of the way
sOundings varied from 1900 to POO fathoms.
the bottom everywhere gently undulating.
The rest OF the summer the Blake was On
ployed in the Cult OF Maine, doing equally
good work.
The sounding apparatus used On the
Blake is the new sounding reel and wire
invented by Sir William Thompson and i'm
proved by Lieutenant Commander Sigsbee.
Ia order to appreciate the vast improve
ment made by this new process consider
that one mile of the wire only weighs four.
teen and half pounds out of the water and
twelve pounds in the water. a man can
carry in coil say fifteen miles of the wire,
while that much rope would cover ships
deck. As the weight attached TO the sound.
ing ROD is tfty-seven pounds, a landsman
would think it impossible for such wire to
hold it; but soundings were made by the
Blake with this wire when the sea was 60
rough that nothing could be done with the
rope, and when the vessel was rolling thirty
five degrees The wire is No. % steel piano
forte wire, and a reel only two and half
feet in diameter carries 5000 fathoms of it,
Commander Sigsbee's experience leads him
to declare that the wire can be used in any
sea.way, no matter how heavy. when it is
possible for vessel to keep head to wind
and go maneuvre with the engines az to keep
the wire vertical or nearly so.
The original idea OF using wire instead of
rope is to be credited to Sir William Thomp-
son, although the machine was first sue
cessfully worked latter an unsuccessful trial
en- the British vessel Challenger by Com.
mander Belknap, United States navy, of
the Tuscarora, in his sourdings across the
Pacific. This machine has been greatly i'm
proved by Lieutenant Commander Sigsbee,
especially as to that part which causes the
reel to cease revolving the instant the
sounding rod strikes the bottom. The lack
o. this was the great defect in sounding
with rope. Not infrequently in deep sound
ings the rope continued to>pay out long
after the sounding rod had struck the bot
tom and the sinker detached. Sir William
Thompson's method of preventing this with
the wire will perhaps be best explained by
giving his own words used in lecture
"A measured resistance is systematically
applied to the reel, which resistance is al
ways more than enough to counterbalance
the weight of the wire out. Suppose, for
instance, the applied resistance is to exceed
by ten pounds the weight of the wire out.
The sinker which I have used is thirty
pounds, the clump four pounds; this gives
US thirty -four pounds. The applied re-
of the wire out reduces this and leaves us
twenty-fOur pounds for the moving force.
But the applied resistance must be increased
as fast as more wire runs out. The wire
weighs twelve pounds q mile in the water,
and $50 fathoms is about one -tourth of q
mile; SO the person in charge watches the
counter and for every additional $50 fathoms
out he adds three pounds to the crank. So,
let the sinker stay at what depth it may,
there will suddenly come to be q resistance
of ten pounds against the motion"
Among the defects of this machine were
first: All the force of the sinker exerted to
revolve the reel was thrown away when it
struck the bottom, and no matter how 40.
curately the man at the register applied
the needed weight the motion was not in
stantly checked. By Commander Sigsbee's
addition this force is accumulated and
thrown upon the friction of the reel the in
slant the sinker strikes bottom; 40 the reel
is immediately stopped. Another defect
was in requiring the additional brakes as
the wire ran out to be applied TO the three
pound weights. Commander Sigsbee's ar
rangement sccomplishes this by means of
coiled spring in cylinder at the top of the
uprights. Thus the friction increases with
perfect regularity as the plummet goes
deeper.
Connected with the axle of the old ma
chine was register which, of course, could
only register the turns of the axle, and by
this the attendant was guided in adding
the weights to the friction. But % the wire
10 coiled on the reel the amount paid out u
9 very little less at each revolution. The