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Page 21
The latter appears to be a common and useless object at the first
glance, but when examined closely it is not so uninteresting. It
measures one and one-eighth of an inch in diameter, and running through
the center are seven bright copper wires, surrounded by a hard, dark
brown substance, the nature of which you do not immediately recognize.
It is gutta-percha, the wonderful vegetable juice, which is as firm as
a rock while it is cold and as soft as dough when it is exposed to
heat. This is inclosed within several strands of Manilla hemp, with ten
iron wires woven among them. The hemp is saturated with tar to resist
water, and the wires are galvanized to prevent rust. You may judge,
then, how strong and durable the rope is, but I am not sure that you
can guess its use.
Near the southern extremity of the western coast of Ireland there is a
little harbor called Valentia, as you will see by referring to a map.
It faces the Atlantic Ocean, and the nearest point on the opposite
shore is a sheltered bay prettily named Heart's Content, in
Newfoundland. The waters between are the stormiest in the world, wrathy
with hurricanes and cyclones, and seldom smooth even in the calm months
of midsummer. The distance across is nearly two thousand miles, and the
depth gradually increases to a maximum of three miles. Between these
two points of land--Valentia in Ireland and Heart's Content in
Newfoundland--a magical rope is laid, binding America to Europe with a
firm bond, and enabling people in London to send instantaneous messages
to those in New York. It is the first successful Atlantic cable, and my
piece was cut from it before it was laid. Fig. 2 on the next page shows
how a section of it looks, and Fig. 3 shows a section of the shore
ends, which are larger.
Copper is one of the best conductors of electricity known, and hence
the wires in the center are made of that metal. Water, too, is an
excellent conductor, and if the wires were not closely protected, the
electricity would pass from them into the sea, instead of carrying its
message the whole length of the line. Therefore, the wires must be
encased or insulated in some material that will not admit water and is
not itself a conductor. Gutta-percha meets these needs, and the hemp
and galvanized wire are added for the strength and protection they
afford to the whole.
It was an American who first thought of laying such an electric cable
as this under the turbulent Atlantic. Some foolish people laughed at
the idea and declared it to be impracticable. How could a slender cord,
two thousand miles long, be lowered from an unsteady vessel to the
bottom of the ocean without break? It would part under the strain put
upon it, and it would be attacked by marine monsters, twisted and
broken by the currents. At one point the bed of the sea suddenly sinks
from a depth of two hundred and ten fathoms to a depth of two thousand
and fifty fathoms. Here the strain on the cable as it passed over the
ship's stern would be so great that it certainly must break. More than
this, the slightest flaw--a hole smaller than a pin's head--in the
gutta-percha insulator would spoil the entire work, and no remedy would
be possible. A great many people spoke in this way when the Atlantic
cable was first thought of, as others, years before, had spoken of Watt
and Stephenson. But Watt invented the steam-engine, Stephenson invented
the locomotive, and Cyrus Field bound Great Britain to the United
States by telegraph.
Early in 1854, Mr. Field's attention was drawn to the scheme for a
telegraph between Nova Scotia and Newfoundland, in connection with a
line of fast steamships from Ireland to call at St. John's,
Newfoundland. The idea struck him that if a line were laid to Ireland,
lasting benefit would result to the world. So he called together some
of his intimate friends, including Peter Cooper, Moses Taylor, Chandler
White, and Marshall O. Roberts, and they joined him in organizing the
"New York, Newfoundland, and London Telegraph Company," which was the
pioneer in the movement to connect the two continents by a telegraph
cable, and without whose aid its consummation would have been
indefinitely delayed.
The work was costly and difficult. The first part consisted in
surveying the bottom of the sea for a route. This was done by taking
"soundings" and "dredgings." As some of you are aware, "sounding" is
an operation for ascertaining the depth of the sea, while "dredging"
reveals what plants and living creatures are at the bottom. After much
patient labor, a level space was found between Ireland and
Newfoundland, and it seemed to be so well adapted to the surveyor's
purposes that it was called the "Telegraphic Plateau."
[Illustration: THE GRAPNEL.]
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