Part 97

A submarine telegraph cable as usually made consists of a core in the center of which is a strand of copper wire which varies in weight from seventy to four hundred pounds to the mile. Strands of copper wire instead of one thick wire of copper are used, because the former is more flexible. The copper conductor is covered with several coatings of rubber of equal weight to the copper wires. After this comes a coating of jute serving, then a layer of galvanized iron wires and finally a layer of yarn and compound which forms the outer covering of the cable. In addition to this where the cable lays among rocks that might injure it, chains are securely wrapped around it, so as to prevent wear and tear as much as possible.

You may not have known it, but the cable which lies on the bottom where the water is deepest is never so large as nearer the shore or in shallow water. Little by little the men who lay and look after cables have found that it is best to have a specially constructed outer covering for different depths and character of bottoms so as to provide the least possible danger of damage through the action of the water on the bottom.

How is a Cable Laid?

When the cable of sufficient length is completed, it is carried to a specially equipped vessel which has a great tank for holding the cable and the necessary machinery for lowering it over the end of the ship into the water. The cable is carefully coiled in the tank, the different coils being prevented from adhering by a coat of whitewash. First then, a sufficient length of cable is paid out to reach the cable house or shore. Here it is finally tested to see that the entire length of cable is in working order. If satisfactorily tested, the vessel steams slowly away on the course outlined, paying out the cable as she goes.

Here we see a cable coiled round and round in the tank which holds it on board the cable ship.]

The paying-out machine. The cable makes a couple of turns around the big drum, which is connected to the dial, so that the dial indicates the length of cable which has been paid out into the sea.]

Here we see the cable on the lead, as it is called, passing over the big bow sheave from which it dives into the depths of the sea.]

The vessel must pay out more than a mile of cable for every mile she travels because there must be enough slack allowed at the same time to provide for the unevenness of the bottom of the sea. For this purpose the amount of cable paid out must be measured. This is done by the paying-out machine, which is shown in one of the pictures. The difference between the speed of the ship and the amount of cable paid out gives the amount of slack. Too much slack would also be bad, so that it is a very pretty problem to pay out just enough and both the speed of the vessel and the rate of paying out the cable must be watched carefully.

One of the greatest wonders accomplished by the ingenuity of man is the ocean telegraph, by which we flash messages back and forth under the sea between the continents and completely around the world.

Hardly had the telegraph become an established fact, before Professor Morse, who made the telegraph practical, expressed the belief that a telegraph line to Europe by means of a wire laid on the bottom of the ocean was easily possible at some future time. Mr. Cyrus W. Field, the first to lay an ocean cable successfully, heard him and in his own mind said “Why not now?” The idea fixed itself so thoroughly in his resolute mind that he soon said to himself “It shall be done,” and went to work, and labored incessantly through twelve years of failure and discouragement before he accomplished his task, which was a great compliment to this giant of American stick-to-it-iveness.

While many doubted the feasibility of the project and others thought it the dream of a disordered brain, Mr. Field found many who believed in him and his idea and who loaned him their financial support for the undertaking.

Landing the shore end of a cable. The cable is supported on several boats and this picture shows the inshore boat with the end of the cable reaching the beach with the seas breaking over her.]

THE PIONEERS OF THE FIRST OCEAN CABLE.]

American genius had not at that time asserted its supremacy in mechanics and so the first cable had to be made in England; so Mr. Field ordered one long enough to stretch from the west coast of Ireland to the eastern point of Newfoundland. English capitalists subscribed the money and the United States provided the vessel in which to store and from which to drop the cable into the ocean.

Upon the first attempt to lay the cable, every thing went along nicely for six days, and then suddenly the cable broke when three hundred and thirty-five miles had been laid, and many said it could not be done. Mr. Field, however, full of American pluck and determination, said “We will try again.” A second attempt was made with two ships, the U. S. S. “Niagara” and H. M. S. S. “Agamemnon.” Each ship carried half the cable and they traveled in company to the middle of the ocean. There the two pieces of the cable were spliced together and the ships started for the shores in opposite directions. Again, however, when only a little of the cable had been paid out--a little more than one hundred miles in fact--the cable broke and both ships were forced to return to England.

In his third attempt the cable was finally laid clear across the ocean and fastened at both ends. When tried it was found to work successfully and Queen Victoria and President Buchanan were able to exchange greetings upon the achievement of a wonderful work. The people celebrated the event on both sides of the ocean, but in the midst of the festivities, while a message was being flashed, something happened to the cable--what, we have never been able to learn--and the cable was silent, forever.

Nothing daunted, however, Mr. Field by his great courage induced his backers to buy him another cable and the “Great Eastern” sailed upon what was to be a most successful mission. Starting from the American side with the greatest steamship then known in charge of the previous cable, the other end was successfully landed at Hearts Content, Ireland, on July 27, 1866, in perfect working order, and the question of the ocean telegraph was solved.

Here is a buoy which is anchored to the cable. The cable ship will pick it up and haul up the cable to the surface for inspection and perhaps it will have to be repaired.]

Here are the powerful engines which are used for picking up a cable which has to be raised from the bottom of the sea for inspection or repair.]

ARMORING MACHINE

Here is one of the machines used for armoring the cable. By armoring is meant winding steel wires around and around the cable to protect it from being cut by sharp rocks on the bottom or by deep sea animals like the teredo, which might attack it.]

CONTINENTAL MORSE CODE SIGNALS USED IN CABLE WORKING]

Making repairs to a cable where it comes out of the sea on to a bold rocky shore. Note how the cable is wound with chain to protect it from the rocks.

Same Signals as They Appear in Actual Working

Here are two photographs showing the continental Morse code signals used in cable working and the signals as they are received by the siphon recording instrument at the receiving station. This siphon recorder is in practical use in the cable world. The dots and dashes sent into the wire on one side of the ocean according to the Morse code, cause the siphon recorder through the means of electrified ink to make a waving line on a tape. The signals are readily reducible again if necessary to the dots and dashes of the Morse code because dots make deflections to one side of the center of the tape and dashes to the other. The operator who receives the message can therefore readily read it.

ALPHABET:

A · -- B -- · · · C -- · -- · D -- · · E · F · · -- · G -- -- · H · · · · I · · J · -- -- -- K -- · -- L · -- · · M -- -- N -- · O -- -- -- P · -- -- · Q -- -- · -- R · -- · S · · · T -- U · · -- V · · · -- W · -- -- X -- · · -- Y -- · -- -- Z -- -- · ·

FIGURES: