Moreover, it has been found that, for delicate and quick-working apparatus, such as automatic telegraphs, polarized relays, and, above all, the telephone, long underground lines are far less efficient than pole lines. I think these facts have sufficiently demonstrated that for long lines of telegraph, stretching from city to city, here in America, pole lines, which can be cheaply built, easily repaired, and where the wires can be removed from the retarding influence of the earth and the inductive influences on each other, are decidedly superior to underground lines. By 1850 the earliest of these lines had failed, and by 1853 the entire system was replaced by pole lines. Although neither expense nor pains were spared in the construction of this line, the cost being comparable with that of the Prussian system, two years had not elapsed before some of the wires ceased to work, and, though these were replaced and workmen kept constantly busy on the line, at the end of seven years the line was wholly abandoned in favor of overhead wires. They were accordingly replaced by wires strung on poles, and the rest of the line was constructed in this way. A brief review of some of the European systems that have been constructed will convince us of this.

The present complete system, as used between Liverpool and Manchester, was constructed as follows: Iron or stoneware pipes were laid from one to two feet below the level of the road-side with flush-boxes coming to the surface every two hundred yards. With ordinary Morse telegraphic apparatus, this is not very troublesome on under-ground lines a hundred miles long. Between 1846 and 1852 many miles of somewhat similar cables were laid in France, but, excepting those laid in the sewers of Paris, they universally failed. Hardly was the section completed, however, when water found its way into the joints, destroying the insulation, and the conductors failed. Mr. Field then directed his efforts to the completion of the trans-oceanic section. The route was especially selected through a low and marshy section of country, so that the pipes were almost constantly filled with water-this being the best possible condition for the preservation of the gutta-percha. 1. If an electric conductor be brought near to a large mass of conducting matter, as is a wire when it is taken down from a pole and buried in the earth, there appears in the current the phenomenon of retardation, by which each signal, instead of being sharp and distinct, is partly kept back, so that it overlaps and mingles with the next; the result is to limit the speed of working of the apparatus; or if, like the telephone, it be an apparatus in which the currents are necessarily extremely frequent, to confuse and destroy the signals altogether.

The details of this work were very carefully carried out, and the experiment is of interest because similar plans are constantly being proposed to-day. Many miles of this cable were laid, some with the lead pipe laid directly in the earth, some with it drawn again into iron pipes, and some carried through the sewers of the principal cities. Many of the European cities have the telegraph lines carried from the center of the city to the outskirts, under-ground; and, in Paris, not only all of the telegraph lines, but those for electric lights, telephones, and the various other private and municipal lines, are carried in the sewers under the streets of the city. This line failed in exactly the same way as the American lines, and the pipes were dug up and placed on short posts six inches above the ground. In 1855 the French government, having failed in their attempt to use gutta-percha wires, laid down a large number of bare wires in a trench filled in with bituminous compounds. In 1852 asimilar cable was laid in Russia, between St. Petersburg and Moscow; this worked a few years and then failed.

Gutta-percha-covered wires were drawn into lead tubes, which were then buried in trenches two feet deep. 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. As to the line itself, Mr. Field consulted Professor Morse, who assured him that it was quite possible to make and lay a cable of that length. Any current-carrying conductor, including a cable, radiates an electromagnetic field. I didn't find anything, and after we'd left, my family even told the owner of the field about what had happened, and she was just as mystified as the rest of us. The speed of working even the ordinary instruments is limited; serious trouble appears in attempting to use fast-working machines, or automatic senders, and the use of the telephone is impossible. It must be remembered, however, that these various systems have cost from ten to twenty times as much as similar overhead lines; that, for every mile of under-ground wire, there are many miles on poles; and that in Paris, which is the only city in the world having a complete under-ground system, there are unusual facilities for the running of wires, as sewers large enough to walk about in extend even under the less important streets of the city.

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