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Page 22
Two or three large vessels were next equipped, and sent out with
several thousand miles of cable on board, which they proceeded to lay.
But the fragile cord--fragile compared with the boisterous power of the
waves--broke in twain, and could not be recovered. A second attempt was
made, and that failed, too. Brave men can overcome adversity, however,
and the little band of scientific men and capitalists were brave men
and were determined to succeed. Each heart suffered the acute anguish
of long-deferred hope, and each expedition cost many hundred thousands
of dollars. Nevertheless, the promoters of the Atlantic cable sent out
a third time, and when failure met them again, it seemed to common
minds that their scheme was a settled impossibility. Not so with the
heroes. Each failure showed them some faults in their plans or
machinery. These they amended. Thus, while they were left at a distance
from the object of their ambition, they were brought a little nearer to
its attainment.
Guided by the light of past experience, they equipped a fourth
expedition. The "Great Eastern" was selected, and her interior was
altered for the purpose. She was, and is still, the largest vessel
afloat. Her length is six hundred and ninety-five feet; her breadth
eighty-five feet, and her burthen twenty-two thousand tons. One of the
principal causes of failure in previous expeditions was the inability
of the cable to endure the severe strain put upon it in stormy weather
as it passed from an ordinarily unsteady vessel into the sea. The
"Great Eastern," from her immense size, promised to be steady in the
worst of gales. Her hold was fitted with three enormous iron tanks---a
"fore" tank, a "main" tank, and an "after" tank. The main tank was the
largest, and eight hundred and sixty-four miles of cable were coiled in
it. Eight hundred and thirty-nine miles in addition were coiled in the
after tank, and six hundred and seventy miles in the fore tank, making
in all two thousand three hundred and seventy-four miles of cable. The
food taken on board for the long voyage in prospect consisted of twenty
thousand pounds of butcher-meat, five hundred head of poultry, one
hundred and fourteen live sheep, eight bullocks, a milch cow, and
eighty tons of ice.
[Illustration: SECTION OF THE GRAPPLING LINE.]
What is called the shore-end of the cable--_i.e._, that part nearest
the shore, which is thicker than the rest--was first laid by a smaller
steamer. It extended from Valentia to a point twenty-eight miles at
sea. Here it was buoyed, until the great ship arrived. On a wet day in
July, 1866, it was joined with the main cable on board the "Great
Eastern," and on the same day that vessel started on her voyage to
Newfoundland.
[Illustration: SECTIONS OF CABLES (REDUCED). 1. Main cable of 1858.
1a. Shore end, abandoned cable of 1858. 2. Main cable of 1866.
2a. Shore-end, recovered cable of 1865. 3. Shore end of cable of 1866.]
It may seem a simple matter to distribute or "pay out" the cable, but
in practice it is exceedingly difficult. Twenty men are stationed in
the tank from which it is issuing, each dressed in a canvas suit,
without pockets, and in boots without nails. Their duty is to ease each
coil as it passes out of the tank, and to give notice of the marks
painted on the cable one mile apart. Near the entrance of the tank it
runs over a grooved wheel and along an iron trough until it reaches
that part of the deck where the "paying out" machine is placed. The
latter consists of six grooved wheels, each provided with a smaller
wheel, called a "jockey," placed against the upper side of the groove
so as to press against the cable as it goes through, and retard or help
its progress. These six wheels and their jockeys are themselves
controlled by brakes, and after it has been embraced by them the cable
winds round a "drum" four times. The drum is another wheel, four feet
in diameter and nine inches deep, which is also controlled by powerful
brakes; and from it the cable passes over another grooved wheel before
it gets to the "dynamometer" wheel. The dynamometer is an instrument
which shows the exact degree of the strain on the cable, and the wheel
attached to it rises and falls as the strain is greater or less. Thence
the cable is sent over another deeply grooved wheel into the sea.
You will remember what I said about insulation,--how a tiny hole in the
gutta-percha would allow the electricity to escape. On deck there is a
small house, which is filled with delicate scientific instruments. As
the cable is paid out, it is tested here. If a wire or a nail or a
smaller thing is driven through it, and the insulation is spoiled, an
instrument called the galvanometer instantly records the fact, and
warning is given at all parts of the ship. The man in charge touches a
small handle, and an electric bell rings violently in the tank and at
the paying-out machinery. At the same time a loud gong is struck, at
the sound of which the engines are stopped. Delay might cause much
trouble or total failure, as the injured section must be arrested and
repaired before it enters the water.
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