The Sun.
London, England, 1858-05-13 00:00:00

ATLANTIC TELEGRAPH.

Since our last notice of the admirable new pay-
submerging this ctible, which
the ,:,xpe; ience ,f the defects of the furm9r appara-

tUB has ef:ab!ed toe company to conztiuct-t for the
attempt now soon to be repeated, gce.,t of otts
insure success to the undertaking have been made.
No precaution has been neglected, no suggestion
(and these have come by thousands) that was worth
attention has been ignored, and all that skill or
science cau effect towards carrying out a scheme in
which so much, unfortunately, depends on chance
has been accomplished. The cable at Key ham has
now been stowed away on board the two vessels
with which last year's attempt was made. Within
the last few days the Adonis quitted the wharf, off
Messrs. Glasse and Elliot's factory, at Greenwich,
with one of the paying-out machines and 300 miles
of cable, in addition to the extra lengths already
made. Since her departure, however, it has been
determined to make 100 miles more, and the ma-
chines at the works are revolving day and night to
complete the extra length in time. The total length
of cable with which the attempt was made last year
was rather under than over 2,400 miles, which was
so near the quantity actually required to span the
distance that the first loss of 300 miles proved fatal
to the whole attempt, for that time at least. Now,
however, the length of cable ou board both vessels
is precisely 3,012 mile., exclu-ive of the shore ends,
of much greater weight and thickness, and which
amount to about 30 miles more. There is therefore

in round numbers 3,050 miles of cable to submerge
between two points only 1,950 statute miles apart,
so that 1,100 miles, or about 40 per cent., is allowed
fur accidents and slack in paying-out. This immense
cable, which weighs about one ton per mile,
will be equally divided between the Agamemnon
and Niagara. The latter has her share distributed
over all her decks, and, of course, most amidships.
There is one coil on the upper or spar deck, be-
tween the fore and main masts, of 100
miles, 30 feet diameter and 2 feet deep, and there
is one of 130 miles, and occupying about the
same space between the main and mizen masts. On
the main deck there are two, one aft and one amid-
ships, of 297 and 294 miles respectively. On the
berth deck there is one of 180 miles, and in the
hold a coil of 350. In place of the shore end, which
was last year carried on the spar deck forward near
the capstan, there will now be a coil of about 100
miles, and the heavy shore ends for both countries
will go its the accompanying frigates. Last year the
cable was coiled in the hold of the Agamemnon in
one vast mass of 1,250 miles long and this immense
weight stowed amidships balanced her like a Chi-
nese toy. The result was, of course, that she rolled
to an extent that it was hard to say which side of
the vessel was uppermost, and on lauding the cable
after the failure of the attempt it was found that the
pressure of the heavy mass on comparatively so
small a surface had strained her timbers to some
extent. To obviate partly these serious disadvan-
tages, therefore—disadvantages which, in case of
the Agamemnon encountering heavy weather,
might and would endanger the safety of the vessel,
—the cattle, though still coiled in the hold,i s dis-
tributed in such a manner that the gt e atest part of
the weight rests on a much larger surface. 1,150
miles will be stowed in the hull, and about 350
miles on the berth deck forward, and to count° :-
balance these heavy masses the coals will bestowed
as far att as possible. All the ships of the squadron
will leave Plymouth, as we have previously an
nounced, about the 24th or 25th of this month on
their experiment Al trip, which will occupy from six
to tea days. During this about 100 miles of con-
demned cable will be used in ascertaining the effi-
ciency of various buoys, laying down and under
running the wire, &C., and when all doubrs and
theories have been practically solved the squadron
returns to Qaeenstown, makes its brief fin prepa-
rations, and starts for the great attempt about the
10th of June. About that period of the year there
is a month of almost uninterrupted calm in the At-
lantic, and anything like seriously heavy weather
has not been heard of at least for the last 50 years.
Bad weather, however, in the ordinary ac-
ceptation of the term, in those boisterous 13-ti-
tucks, even if it does occur, is not likely to
affect the process of submerging after it has once
fairly commenced, for t he paying-out mtchine is so
sufficiently self-acting as to almost compensate in
its action for any sudden rise in the stern of the
vessel to the pitch of the sea. Beth ships, with the
accompanying frigates, make all speel to the centre
of the Atlantic, or rather to the centre of the space
to be traversed by the cable, which is about 32 deg.
west of Greenwich. Here the splice between the
two halves will be made without loss of time. To
overcome the difficulty caused by the two portions
of the cable having their " lay" or t mist of the out-
side spiral wires turning in different directions, and
forming right and left baud screws, the splice will
be secured to rods of iron loaded with a weight in
the centre; in f an apparatus of the same kind
as that by which railway carriages are coupled.
together. By this means the tend.,,ncy of the diffe-
rent spirals to untwist each other will be overcome.
There is 1,500 fathoms water where this join must
he made, and both vessels will remain stationary
until the splice has well settled oa the bottom,
when the Niagara will at once steer for the New
World, and the Agamemnon return to the Old.
Each will steam as fast to her homeward destina-
tion as is consistent with the safety of the great
undertaking, so the cable will be either laid or lost
within 12 or 14 days from starting. The depths to
which the Niagara will have to sink her portion
vary quickly and irregularly from 1,500 to 2,500
fathoms, or from 1 to about 3i miles ; and this is
the case also with the Agamemnon's potion of the
distance. But on the American side the water
shoals easily and gradually towards Newfoundland,
whereas on the British portion of the ocean the

Agamemnon will have to surmount a tremendous
ridge, which may be called the Andes of those vast
submarine plains of the Atlantic. It commences at
about 15 deg. west longitud-, and in the course of
a few miles the water suddenly shoals from 1,750
fa hocns to 550. Up this vast rocky precipice—
almost as steep as the side of Mont Blanc—the
cable must be laid with extreme care. This diffi-
culty once overcome, the way thence to Valentia
b!comes compara-ively of no account.

In case of dangerous weather arising the first
con4deration in all cases will be, of course, the
satety of the cable ; and, no muter how advanta-
geous such and such courses of action may app far,
nothing will be done by which the success of the
undertaking is jeopardised or even left to chance.
Each vessel is provided with reels of strong wire
rope which can be attached to buoys made in the
manner of ordinary fishing floats, though, of course
capable of sustaining a weight of several tons. Pro-
vided with this apparatus, the cable may be cut
without reluctance, if ever the weather threatens,
and the end of it (firmly secured to the rope and
buoy) allowed to rest alwo-t upon the bed of the
ocean, to be hauled up directly the storm has
passed. Proper precautions have also been taken
to make the floating ends of the buoys conspicu,us
And easily found in case of -the ships being driven
from them.

A number of experiments have recently been
made with- a view of increasing the rapidity of
working signals through the entire length of the
cable. These experiments, in which a variety o'
inventions and applications have been employed,
have been conducted by Professor Thompson, Mr.
Hughes, the American electrician (whose printing
telegraph is likely to revolutionise the present un-
certain system), Mr. Henley and Mr. Whitehouse.
The result, though on the whole far more satisfac-
tory than was at first anticipated, shows indubit-
ably that more than one submarine cable will be
required to do all the business likely to be trans-
acted between this country and the New World.
Such a result, however, need dishearten no. one,
since none but those unacquainted with the subject
have for a moment imagined that one working ca-
ble would, be sufficient, or do more than show the
way which others will be soon ready. and anxious to
follow. How many wires are there kept incessantly
employed between London and Liverpool and be-
tween Liverpool and Ire!and, where cost of the
post is only a penny, and the delay in using it only
a few hours ? Yet we believe that nearly 30 wires
are scarcely sufficient to meet the demand for mes
sages between these places. Taking this, then, as the
standard, how many aubmarine cables will be re-
quired for the business between the New World
and the Old? If we are not much mistaken, the
messages to New Orleans alone would employ and
richly pay one cable. At all events, if it is only
f.r the purpose of counteracting the disturbing in-
fluence of those mysterious magnetic storms, it
will be necessary for the Atlantic Company to lay
down a second wire as soon as possible,—that is,
to have a complete metallic circuit for the rani-,
of the electricity along the outer wires of the second
cable, instead of being discharged by the earth.
Formerly. the signals we:e worked through the
Atlantic coil by means of a Simei'a battery of 48
large cells with large induction c',ils, constituting
probably the moat powerful battery ever c ,n-
-structed. How insulation of the cable withstood
this severe test is an enigma. It has, however,
since b..en ascertained that an ordinary battery of
six cells transmitted the signals with the same
facility, and that, in fact, the quantity of electri
city generated by the enormous power of the first
battery choked or charged the wre.
Mr. Heuley has recently been making a number
of experiments upon the cable at his own expense,
with the view of perfecting a very simple and beau-
tiful magneto-electric machine, by which a current
s transmitted greater in intensity, though much
less in quantity, than the ordinary galvanic cur-

rent, and thus the liability of the wire to become
charged is considerably reduced.
The immen<e advantages which a magneto-elec-
tric pe,sesEe:i over an ordinary battery are
of altr.os' incalcutible importance. It is always
• ready, can be used anywhere, at any time, and by
any rerso, ; and, ab ye all, is no exi erase beyond
the nose, of M k'ng i Io faci, rie differ-rice
between Mr. Henley's machine and an o dinary
battery is as great as between the electric and old
semaphore telegraphs, or as great as the difference
which would exist between an ordinary musket
and one constructed on such inevitable laws as to
keep itself always loaded, clean, and ready for
action. It consists of an ordinary large permanent
magnet, between the poles of which a soft iron mag-
net, with its coils of secondary wire, is fixed. By this
arrangement it is necessary only to deflect the
keepers of the magnet to produce an equal current
at all velocities, and either in one direction or al-
ternately backwards and forwards. The magnet is
2 feet 10 inches high, and consists of 30 plates of the
finest steel, a quarter of an inch thick and 4 inches
broad. The soft magnet is formed of 44 soft iron
plates in a mass 3 inches broad and 2 deep, and of
the same height as the permanent magnet. The se-
condary coils for producing the current in the poles
of these magnets contain (each) 25 miles of the
finest silk-covered wire, or 100 miles for the four
magnets. With this machine alread3 8 words per
minute can be sent through the cable in its present
condition, and of c6urse the words can be transmit-
ted with greatly increased rapidity when the cable
is laid out in a straight course, for no position could
be more unfavourable for transmitting signals than
that in which the wire is at present stowed, in huge
coils one over another. Up to the present all looks
well and hopeful for the success of this great scheme,
and we earnestly trust that after a few weeks more
all doubts and misgivings will be solved in the most
gratifying and conclusive manner.