The Sun.
London, England, 1866-06-28 00:00:00

Atlantic Telegraph Expedition.

All the final arrangements for the sailing of this
great mechanical and scientific expedition were set-
tled on Tuesday. The great ship is now receiving
her last length of cable from the Iris, and the coil-
ing of this and the final closing of the tank, to
secure it from accidental injury, will be completed
by to-day. The directors and a few invited guests
then pay a farewell visit, and after that none will
be allowed on board any of the vessels of the wire
squadron, save the representatives of the press and
those actually connected with the work of testing
and laying the cable. Every part of the Great
Eastern has now been got into the most perfect
order. The machinery by which in less than four
minutes her paddles can be disconnected and made
to work independently of each other has been tried
and found to answer admirably, and this improve-
ment is of the last importance in keeping the ship
on the same spot while engaged in hauling up the
cable laid last summer. It was then attempted to
put a very powerful wrought iron guard over the
screw, so that in backing astern full power there
should not be the least risk of the screw fouling the
cable. For this purpoie the great ship was trimmed
down by the head considerably, in order to bring her
stern well out of water. After a while, however, it
was wisely decided not to affix such a guard, and
those who remember the imminent risk of loss to
which the Agamemnon was exposed in the storm of
1858 by a similar apparatus will not be sorry to
hear that the Great Eastern will sail without one
this time. On all vessels where it has been tried it
has never been of the slightest use, and always a
source of more or less serious apprehension. In
backing over the cable, therefore, the Great
Eastern will use her paddles only. The floats
of these latter have been reduced by about a
third of their width, and reefed in towards
the axle, so as virtually to reduce them to a
third of their diameter. This diminution of
both surface and size will, of course, have a very
material effect on the question of speed, and even
after the careful cleansing the bottom has got not
more than a knot an hour over the speed of last
year is expected this time. Some old lengths of last
year's cable have been stowed away on board the
Albany and Medway. The Irish shore end is soiled
on board the William Corry, which ship will leave
with the Great Eastern. We much underrated the
strength of this latter ponderous coil in a previous
notice. The limit of its breaking strain has never
been ascertained, but it is enormous. The outer
covering is formed of wires or rather iron bars
almost as thick as ordinary pokers, and it weighs
upwards of 20 tons to the mile—nearly double the
size and strength of the largest submarine cable
ever made. The ships which are to take fuel for the
Great Eastern to Berehaven have already started,
and the whole squadron will sail from the Medway
on Saturday next. The tide on that day will suit
perfectly, but, as the Channel is devious and the
Great Eastern deep, she will only go at very slow
speed till past the Downs, being carefully piloted so
far by a Government vessel, which will precede her.
At Berehaven she will fill up the rest of her coal
while the William Corry is laying the shore end
from under the cliffs at Valentia. This labour over,
hr:: th
the splice will be made, and the Great Eastern will
e new
commence
nece her work. For the first 100 miles from
B
cable will be used, but down the
gentle incline,
into deep water, known in deep-sea
Nomenclature as the Irish bank, 300 miles of the cable
ptoolf
olNya
esedt yw.f aoTurhnev ra
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alnlntbdi er
etu shyeeodyn,
eawndefOr the rest of the route
age
(math? cable
no accident
al
ccoindleyhtb
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is expected to occupy not more thanten days. Themer
eelxleduietidoenrsatoofodlBsB
is to be an important alteration in the plan of elec-
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what
ayte
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operations
and 1865 proved,
merely
the Atlantic, but
engineers, that there is no difficulty in by
laying a wire rope across to lay
such a rope with an insulated telegraph conductor
in its interior without damaging its integrity has
, hitherto proved impracticable. This year, as we
have said, great improvements have been made in
the plan and apparatus for testing the electrical con-
dition of the line. The Telegraph Construction and
Maintenance Company have secured the professional
services of those eminent electricians, Professor
William Thomson and Mr. Cromwell Parley, who
are now the consulting electricians of that companY•

Last year the tests for determining the condition
of faults and also the strength of earth currents were
Performed on board ship. This year accurate tests
will be made at both ends of the cable and a con-
tinuous exchange of results will be telegraphed from
one to the other, the information which the shore
can give to the ship being of the highest importance
to enable those on board ship to find out the position
of a fault accurately and rapidly should any unfor-
tunately OMIT. The principal batteries used for
testing will be on board ship, and the shore will have
to read off and decipher these indications without

any other access to the battery than what is afforded
through the cable.

It is of the utmost consequence that the most com-
petent electrkians should be at each end of the cable,
and it has been, therefore, finally decided that one
of the consulting electricians shall be at each end of
the line during the operation of paying out. Pro-
fessrm Thomson will go out in the Great Eastern
NO,th Mr. Willoughby Smith, while Mr. C. F. Varley
'will remain at Valentia.

Mr. It. A. Glass, who will be also at Valentia
during the submergence, will this time be assisted by
the presence of highly competent authority in elec-
trical matters, and such information will be ex-
changed almost hourly through the cable as will
enable those on shore to know not only the posi-
tion of the Great Eastern and the amount of cable
paid out, but also the electric condition of the cable
and the approximate distance of faults, should any
unfortunately be discovered. It is worthy of remark
that during the manufacture of the 1865 cable and
its being coiled on board the Great Eastern several
faults occurred. This year there has not been a
single one, which is a good omen of success for this
great enterprise. Messrs. Thomson and Varley will
remain for some time at each end of the line after it
has been laid, to work the cable by their new appa-
ratus, known as the curb key. Mr. S. Canning, Mr.
H. Clifford, and Mr. Temple are in absolute charge
of the duties relating to laying the cable, and after-
wards finding the broken end of that so unfortu-
nately lost last year. Capt. Anderson, assisted by
his chief officer, Mr. Halpin, has entire command of
the ship. in case that a fault be indicated by the
electric test at any time during the paying out, the
course to follow will be instantly, on an order being
given by an officer in the electric room, to stop and
reverse the ship's engines, and to put on the greatest
safe-weight on the paying-out break. Thus, in the
course of a very short time, the egress of the cable
may be stopped, and if the weather be propitious
the vessel may be kept, by judicious use of paddles,
screw, and rudder in the required position for hours
to allow the cable to hang almost vertically, with
little more strain than the weight of the length of
that portion of it between the ship and the bottom
of the ocean. The best system of electric testing
that has been brought into actual use, or even
planned, cannot show within less than a mile the
position of a fault consisting of a very slight loss of
insulation unless both ends of the cable be at
hand. Whatever the character of the flaw may be,
unless the electric tests demonstrate its position to
be remote from the outgoing part, the only thing
that can be done to find whether it be just on board
or just overboard is to cut the cable as near the
outgoing part as the mechanical circumstances will
permit. The electric test immediately transferred
to the fresh-cut seaward end will indicate instantly
if the insulation be perfect between it and the shore.
A few minutes more, and the tests applied to the
two ends of the remainder on board will show very
closely the position of the fault, whatever its cha-
racter may be. The engineers will then be able to
make proper arrangements immediately for re-splic-
ing and paying out good cable, and for cutting out
the fault from the imperfect part. But if this fault
occurs between the land end and the fresh-cut sea-
warJ end on board ship, proper simultaneous tests
on board ship and on shore must be employed to
ascertain whether the fault lies so near the vessel as
to make it advisable to haul back the cable until it
is got on board. This plan has not hitherto been
much adopted, but if properly executed it is sure to
be efficacious. If, then, it be necessary to haul back
the cable, steam-power must be applied to reverse
the paying-out machine, and by careful watching of
the dynamometer, never letting it go above 60 or 65
cwt., and controlling the power accordingly, • the
cable, which can bear a strain of 7 tons, will not
break, and the fault will be got on board more surely,
and possibly in a shorter time, than a " sulky sal-
mon" of 301 b. weight can be landed by an expert
angler with a rod and line that could not bear 161 b.
A question suggests itself :—How is the cable of last
year to be brought to the surface when hooked? The
operations of last August failed from the fact that
the available rope tackle and hauling machine were
not strong enough for this unexpected experiment.
On no occasion, however, was the electric cable itself
broken. The strongest rope employed last year in
raising it consisted of iron wire and hemp spun
together. This was capable of bearing 14 tons, and
had been prepared merely as a buoy rope, and was
all in 100 fathom lengths, joined by shackles with
swivels. It had been manufactured to provide for
the contingency of being obliged, by stress of wea-
ther or other causes, to cut or leave the cable in
deep or shallow water. The wire rope itself never
gave way, but on two or three occasions a swivel
yielded. At one point of the operation of hauling
in, 900 fathoms of Manilla rope had to be employed
for the upper part, there not being enough of wire
rope left ; and when 700 fathoms had been got in,
it broke on board beside a shackle, and the remain-
ing 200 fathoms of Manilla rope, withl,slo fathoms
of wire rope, the grapnel, and the.electric cable which
it had hooked, were all lost for the year 1865. With
tackle sufficiently strong, and the hauling machine
of adequate power, both being under perfect control,
the lifting of a submarine cable, as good in mecha-
nical quality as that of 1865, even from a depth of
two nautical miles, is apparently practicable. The
several plans of proceeding that have been proposed
are of two classes—those in which by three or more
ships it is proposed to bring a point of the cable to
the surface without breaking it at all ; and those in
which it is to be cut oz broken, and a point of the
cable eastward from the break is to be brought to
the surface.

With reference to either plan it is to be remarked
that by lifting simultaneously by several grapnels
so constructed as to hold the cable without slipping
along it or cutting it is possible to bring a point
of the cable to the surface without subjecting it
to an strain amounting to the weight of a length
of cable equal to the depth of the water. But so
many simultaneous grapplings by ships crossing the
line of cable at considerable distances from one
another would be required that this possibility is
scarcely to be reckoned on practically without cut-
ting or breaking the cable at a point westward of the
parts raised by the grapnels. On the other hand,
with but three ships the cable might, no doubt, be
brought to the surface at any point along the line
without cutting it, and without subjecting it to much
more strain than the weight corrseponding to the
vertical depth, as is easily seen when it is considered
that the cable was laid generally with from 10 to
15 per cent. of slack.'
The plan which seems surest and simplest is to
cut the cable at any chosen point, far enough east-
ward of the present broken end to be clear of en-
tanglement of lost buoy rope, grapnels, and the
loose end of the electric -cable itself ; and then, or
as soon as possible afterwards, to grapple and lift
at a point about three miles further eastward. This
could be well and safely accomplished by two ships,
one with a cutting grapnel and the other—the Great
Eastern herself—with a holding grapnel. The latter
on hooking will haul up cautiously, never going
beyond a safe strain, as shown by the dynamometer.
The other, when assured that the Great Eastern
has caught the cable, will haul up at first cautiously,
but ultimately, when the cable is got well off the
bottom by the big ship, the vessel on the west will
move slowly eastwards and haul up with force enough
to cut or break the cable. This leaves three miles of
free cable on the western side of the Great Eastern
grapnel, which will yield freely eastwards, even
though partly lying along the bottom at first. She
will then be able to haul up and work steadily east-
ward, so as to keep her grappling rope, and there-
fore ultimately the portion of the electric cable,
hanging down on the two sides of the grapnel, as
nearly vertical as is necessary to make sure work of
getting the cable on board the vessel.
The handiness of the Great Eastern, about which
so much scepticism has prevailed, has been proved to
be very much better than was expected, and to be
sufficient for the requirements of the expedition in
moderately fair weather. She has both screws and
paddles, an advantage possessed by no other steamer
in existence. By driving the screw at full power
ahead and backing the paddles, to prevent the ship
from moving ahead, or in case the screw should over-
power the paddles by driving thepadtdhle scesfrtet
aheadper
astern, and driving at the same time
with power enough to prevent the ship from going

astern, " steerage way" is created by the lash of
water from the screw against the rudder, and
by this means the Great Eastern can be steered
effectually without going ahead. Thus she is in
calm or moderate weather as manageable as a small
tug steamer, with reversing paddles, or even as a
rowing boat. She has been made still more con-
trollable than she was last year by the adoption of a
plan to disconnect either paddle at any moment—a
plan which we have said has been most successfully
accomplished. It may, perhaps, be interesting to
state that during the past winter, and, indeed, up
to the present day, the half of the cable laid last
year has been incessantly watched and tested night
and day. These tests show with great certainty
that, up to the point of fracture, the cable is elec-
trically perfect, and has actually improved in con-
dition since it was first laid.