Heroes of the Telegraph/Chapter 4 > 자유게시판

On the French Atlantic it is usually about thirteen, although as many as seventeen have sometimes been sent. On August 16 Queen Victoria sent a telegram of congratulation to President Buchanan through the line, and expressed a hope that it would prove 'an additional link between the nations whose friendship is founded on their common interest and reciprocal esteem.' The President responded that, 'it is a triumph more glorious, because far more useful to mankind, than was ever won by conqueror on the field of battle. The Morse and other instruments, however suitable for land lines and short cables, were all but useless on the Atlantic line, owing to the retardation of the signals; but the mirror instrument sprang out of Thomson's study of this phenomenon, and was designed to match it. To these gifts of theory, electrical and mechanical, Thomson added a practical boon in the shape of the reflecting galvanometer, or mirror instrument. A pressure-gauge to register the depth of the sinker has been added by Sir William.

Sir William (then Professor) Thomson first solved the difficulty by his invention of the 'mirror galvanometer,' and rendered at the same time the first Atlantic cable company a commercial success. Once more the middle splice was made and lowered, and the ships parted company a third time. On Saturday, the 26th, the middle splice was effected and the bight dropped into the deep. They were to meet in the middle of the Atlantic, where the two halves of the cable on board of each were to be spliced together, and while the Agamemnon payed out eastwards to Valentia Island the Niagara was to pay out westward to Newfoundland. He descended in their midst like the very genius of electricity, and helped them out of all their difficulties. Another splice, followed by a fresh start, was made during the same afternoon; but when some fifty miles were payed out of each vessel, the current which kept up communication between them suddenly failed owing to the cable having snapped in the sea. To Bright therefore belongs the distinction of laying the first Atlantic cable and of first establishing telegraphic communication between Europe and America. The vessels and their consorts met in the bay of Valentia Island, on the south-west coast of Ireland, where on August 5, 1857, the shore end of the cable was landed from the Niagara.

The vessels left the Cove of Cork on July 17; but on this occasion there was no public enthusiasm, and even those on board felt as if they were going on another wild goose chase. Apart from the noise of the paying-out machinery, there was an awful stillness on board. We feel that there is no possibility of things going on for ever as they have done for the last six thousand years. He asked the defendant to put it up, take it down after the election and attend to it for him, saying that he did not want to have anything to do with it. These waves, encroaching upon each other, will coalesce at their bases; but if the crests remain separate, the delicate decipherer at the other end will take cognisance of them and make them known to the eye as the distinct signals of the message. If a positive current-that is to say, a current from the copper pole of the battery-gives a deflection to the right of zero, a negative current, or a current from the zinc pole of the battery, will give a deflection to the left of zero, and vice versâ.

This measurer of the current was infinitely more sensitive than any which preceded it, and enables the electrician to detect the slightest flaw in the core of a cable during its manufacture and submersion. In a few days the whole of the capital was subscribed, and Bright (at the age of twenty-four) was appointed engineer-in-chief to the company, and Whitehouse electrician. On 10 June 1858 the fleet sailed for mid-Atlantic (Bright's plan was now adopted), but again failure ensued, and the ships returned to Plymouth ; though one section of the directors was ready to abandon the whole scheme, it was finally decided to make one further attempt. In 1857 he published in the Engineer the whole theory of the mechanical forces involved in the laying of a submarine cable, and showed that when the line is running out of the ship at a constant speed in a uniform depth of water, it sinks in a slant or straight incline from the point where it enters the water to that where it touches the bottom. He showed that the velocity of a signal through a given core was inversely proportional to the square of the length of the core. It was now possible to calculate the time taken by a signal in traversing the proposed Atlantic line to a minute fraction of a second, and to design the proper core for a cable of any given length.

Here's more information on what is electric cable check out our own page.