The land telegraph having had such success, the next step was to carry
the wires across the deep, and link continent to continent,--an
all-important step for an island kingdom such as ours, with its legion
of distant colonies. The success of a submerged cable between Gosport
and Portsmouth, and of one across the docks at Hull, proved the
feasibility of a water telegraph, at least on a small scale, and it was
not long before more ambitious attempts were made. On the 28th of August
1850, a cable, 30 miles long, in a gutta percha sheathing, was stretched
at the bottom of the straits between Dover and Cape Grisnez, near
Calais. Messages of congratulation sped along this wire between England
and France; and although a ridge of rocks filed the cable asunder on the
French coast, the suspension of communication was only temporary. The
link has once more been established, and is in daily use. The first news
sent by the wire to England was of the celebrated _coup d'etat_ of the
2d December, which cleared the way for Louis Napoleon's ascent of the
throne. Numerous other cables have since been sunk beneath the waters;
complete telegraphic communication has just been established between
England and India, and will, no doubt, before long be extended to
Australia.
The greatest enterprise of this kind, however, still remains
unaccomplished--that is, the laying of the Atlantic cable. A company was
started in 1856 to carry out this great enterprise, the governments of
Great Britain and the United States engaging to assist them, not only
with an annual subsidy of L10,000 a-year for twenty-five years, but to
furnish the men and ships required for laying the cable from one side of
the Atlantic to the other. The chief difficulty which engaged the
attention of Mr. Wildman Whitehouse and the other agents of the notable
enterprise was the enormous size of the cable which, it was thought,
would be necessary. The general belief at that time was, that the
greater the distance to be traversed, the larger must be the wire along
which the electric current was to pass, and that the rate of speed would
be in proportion to the size of the conductor. Mr. Whitehouse, however,
thought it would be as well to begin by making sure that this was really
the case, and that a monster cable was essential; and after some three
thousand separate observations and experiments, was delighted to find
that the difficulty which stared them in the face was imaginary. Instead
of a large cable transmitting the current faster than a small one, he
ascertained beyond a doubt, that the bigger the wire, the slower was the
passage of the electricity. It would be needful, therefore, to make the
cable only strong enough to stand the strain of its own weight, and
heavy enough to sink to the bottom. A single wire would have been quite
sufficient, but a strand of seven wires of the finest copper was used
for the cable, so that the fracture of one of them might not interfere
with the communication,--as long as one wire was left intact the current
would proceed. A triple coating of gutta percha, to keep the sea from
sucking out the electricity, and a thick coating of iron wire, to sink
the cable to the bottom and give it strength, were added to the copper
rope, and then the cable was complete. No less than 325,000 miles of
iron and copper wire were woven into this great cable,--as much as might
be wound thirteen times round the globe; and its weight was about a ton
per mile. The length of the cable was 18,947 miles--some 600 miles being
allowed to come and go upon, in case of accidents.
The end of July 1857 was selected for the sailing of the ships that were
to lay the cable, as fogs and gales were then out of season, and no
icebergs to be met with. On the 8th of August, the _Agamemnon_ (English)
and _Niagara_ (American), with four smaller steamers to attend them, and
each with half of the mighty cable in her hold, got up their steam and
left Valentia Harbour. One end of the cable was carried by a number of
boats from the _Niagara_ on shore, where the Lord-Lieutenant was in
waiting to receive it, and place it in contact with the batteries, which
were arranged in a little tent upon the beach. A slight accident to the
cable for a little while delayed the departure of the ships; but by the
10th they had got 200 miles out to sea, and so far the cable had been
laid successfully. Messages passed and repassed between the ships and
the shore. The next day the engineer discovering that too much cable was
being paid out, telegraphed to the people on board to put a greater grip
on it; the operation was clumsily managed, and the cable snapped,
sinking to a depth of 12,000 feet.
Not disheartened, however, the Company replaced the lost portion of the
cable; the Government again furnished ships and men, and the cable was
actually laid at the bottom of the Atlantic from Valentia Bay to Trinity
Harbour.
Addresses of congratulation passed between the Queen and the President
of the States, and numerous messages were transmitted. But gradually the
signals grew fainter and more faint, till they ceased altogether. The
cable was stricken dumb. A little to the north of the fiftieth parallel
of latitude, at the bottom of the Atlantic, where the plateau is
unbroken by any great depression, some 1500 miles of the disabled cable
were lying, on a soft bed of mud, which was constantly thickening, at a
depth of from 10,000 to 15,000 feet.
The importance of telegraphic communication between England and the
United States was, however, so obvious that its projectors were not to
be daunted by the failure they had sustained. Nor was it altogether a
failure. They had proved that a cable _could_ be laid, and messages
flashed through it. What was wanted was evidently a stronger cable,
which should be less liable to injury, and more perfect in its
insulation of the telegraphic wires.
From 1858 to 1864, the Company were engaged in the difficult task of
raising fresh funds, and in endeavouring to secure grants from the
British and American Governments. Their men of science, meanwhile, were
devising improvements in the form of cable, and contriving fresh
apparatus to facilitate its submersion. Eventually the Telegraph
Construction and Maintenance Company, an union of the Gutta Percha
Company with the celebrated firm of Glass and Elliott, constructed an
entirely new cable, which was not only costlier, but thicker and
stronger than the preceding one. The conductor, three hundred pounds per
mile, and one-seventh of an inch thick, consisted of seven No. 18 copper
wires, each one-twentieth of an inch in thickness. The core or heart of
the cable, says a writer in "Chambers's Encyclopaedia," was formed of
four layers of gutta percha alternating with four of Chatterton's
compound (a solution of gutta percha in Stockholm tar); the wire and
conductor being seven hundred pounds per mile, and nine-twentieths of an
inch thick. Outside this was a coating of hemp or jute yarn, saturated
with a preservative composition; while the sheath consisted of ten iron
wires, each previously covered with five tarred Manilla yarns. The whole
cable was an inch and one eighth thick, weighed thirty-five and
three-quarter hundredweights per mile, and was strong enough to endure a
breaking strain of seven tons and three-quarters. During the various
processes of manufacture, the electrical quality of the cable was tested
to an unusual extent. The portions of finished core were tested by
immersion in water at various temperatures; next submitted to a pressure
of six hundred pounds to the square inch, to imitate the ocean pressure
at so great depth; then the conducting power of the copper wire was
tested by a galvanometer; and various experiments were also made on the
insulating property of the gutta percha. The various pieces having been
thus severely put to the proof, they were spliced end to end, and the
joints or splicings tested. In a word, nothing was left undone that
could insure the success or guarantee the stability of the new cable.
When completed, the cable measured two thousand three hundred miles, and
weighed upwards of four thousand tons. It was felt that such a burden
could only be intrusted to Brunel's "big ship," the _Great Eastern_. For
this purpose three huge iron tanks were built, in the fore, middle, and
aft holds of the vessel, each from fifty to sixty feet in diameter, and
each twenty and a half feet in depth; and in these the cable was
deposited in three vast coils.
On the 23rd of July 1865, the _Great Eastern_ left Valentia, the
submarine cable being joined end to end to a more massive shore cable,
which was hauled up the cliff at Foilhummerum Bay, to a telegraph-house
at the top. The electric condition of the cable was continually tested
during the ship's voyage across the Atlantic; and more than once its
efficiency was disturbed by fragments of wire piercing the gutta percha
and destroying the insulation. At length on August 2nd, the cable
snapped by overstraining, and the end sank to the bottom in two thousand
fathoms water, at a distance of one thousand and sixty-four miles from
the Irish coast. Attempts were made to recover it by dredging. A
five-armed grapnel, suspended to the end of a stout iron-wire rope five
miles long, was flung overboard; and when it reached the bottom, the
_Great Eastern_ steamed to and fro in the direction where the lost cable
was supposed to be lying; but failure followed upon failure, and the
cable was never once hooked. There remained nothing to be done but for
the _Great Eastern_ to return to England with the news of her
non-success, and leaving (including the failure of 1857-8) nearly four
thousand tons of electric cable at the bottom of the ocean.
The promoters of ocean telegraphy, however, were determined to be
resolute to the end. A new Company was formed, new capital was raised,
and a third cable manufactured, differing in some respects from the
former. The outside jacket was made of hemp instead of jute; the iron
wires of the sheath were galvanized, and the Manilla hemp which covered
them was not tarred. Chiefly through the absence of the tar, the weight
of the cable was diminished five hundred pounds per mile; while its
strength or breaking strain was increased. A sufficient quantity of this
improved cable was made to cross the Atlantic, with all due allowance
for slack; and also a sufficient quantity of the 1865 cable to remedy
the disaster of that year.
On July 13th, 1866, the _Great Eastern_ once more set forth on her
interesting voyage, accompanied by the steamers _Terrible_, _Medway_,
and _Albany_, to assist in the submersion of the cable, and to act as
auxiliaries whenever needed. The line of route chosen lay about midway
between those of the 1858 and 1865 cables, but at no great distance from
either. The _Great Eastern_ exchanged telegrams almost continuously with
Valentia as she steamed towards the American continent; and great were
the congratulations when she safely arrived in the harbour of Heart's
Content, Newfoundland, on the 27th.
Operations were next commenced to recover the end of the 1865 cable, and
complete its submergence. The _Albany_, _Medway_, and _Terrible_ were
despatched on the 1st of August, to the point where, "deep down beneath
the darkling waves," the cable was supposed to be lying, and on the 9th
or 10th they were joined by the _Great Eastern_, when grappling was
commenced, and carried on through the remainder of the month. The cable
was repeatedly caught, and raised to a greater or less height from the
ocean bed; but something or other snapped or slipped every time, and
down went the cable again. At last, after much trial of patience, the
end of the cable was safely fished up on September 1st; and electric
messages were at once sent through to Valentia, just as well as if the
cable had not had twelve months' soaking in the Atlantic. An additional
length having been spliced to it, the laying recommenced; and on the 8th
the squadron entered Heart's Content, having thus succeeded in laying a
second line of cable from Ireland to America.
The two cables, the old and the new, continued to work very smoothly
during the winter of 1866 and 1867; but in May 1867, the new cable was
damaged by an iceberg, which drifted across it at a distance of about
three miles from the Newfoundland shore. The injury was soon repaired;
but again, in July 1867, the same cable broke at about fifty miles from
Newfoundland.
The earlier cable continued to work for several years, but both cables
gave way towards the close of the autumn of 1870. No special
inconvenience was felt, however, as two years ago a French line of
cable was laid down between Europe and America; the _Great Eastern_
being again employed, and the operations being conducted under the
superintendence of English electricians. The two British cables will
probably be repaired in the spring of the present year (1871).
Submarine cables have multiplied recently, and almost every ocean flows
over the mysterious wires which flash intelligence beneath the rolling
waters from point to point of the civilized world. By a telegraph-cable,
which is partly submarine, the India Office in Westminster is united
with the Governor-General and his Council at Calcutta. There is also
communication between Singapore and Australia, and the network of ocean
telegraphy is being so rapidly extended that, before long, the British
Government in the metropolis will be enabled to convey its instructions
in a few hours to the administrative authorities in every British
colony. And thus the words which the poet puts into the mouth of "Puck"
will be nearly realized in a sense the poet never dreamed of--"I'll put
a girdle round about the world in forty minutes."
The Silk Manufacture.
I.--JOHN LOMBE.
II.--WILLIAM LEE.
III.--JOSEPH MARIE JACQUARD.
The Silk Manufacture.