HISTORY AND STATISTICS. The feasibility laying a line for the transmission of signals along the bottom of the ocean seems to have been first suggested in 1795 by a Spaniard named Salvia. Eight years later a nephew of the famous electrician Galvani performed ex periments of a similar nature in the deep sea off Calais. The first really important experiments. however, bearing directly upon this subject are believed to have been those of Summering and Schilling, who in 1811 applied a soluble insulat ing material to a conductor which was laid across the river Isar near Munich. These investigators also used a submarine conductor to explode gun powder by an electric current. In 1813 an Eng lishman named John Sharpe transmitted signals through seven miles of insulated copper wire laid on the bottom of a pond, but the first practical attempt to use such a conductor to transmit telegraphic signals was by Colonel Paisley of the Royal Engineers at Chatham, England, in 1838. He surrounded his conductor with strands of tarred rope and wrapped the whole with pitched yarn. In 1839 Dr. W. O'Shaughnessy at Cal cutta laid across the lIngli River copper wire cov ered with bamboo and then coated with cotton and tar. In 1840 Wheatstone proposed a scheme similar to those of the last two inventors, and later suggested the use of gutta-percha as a cov ering for the wire, but was unable to put his idea into practice. Prof. S. F. B. Morse, of New York, laid an insulated cable between Castle Garden and Governor's Island, and as a result of his experiments came to the conclusion "that a tele graphic communication on his plan might with certainty he established across the Atlantic." The idea that submarine conductors for tele graphic purposes could be constructed was rapid ly taking root, and in 1845 the Messrs. Brett, who were active in the construction of the first telegraphic lines across the English Channel and the first Atlantic cable, registered a 'General Oceanic Telegraphic Company' for the purpose of establishing telegraphic communication between England and America. In 1850 an experimental line was laid across the English Channel by the Messrs. Brett, and this was followed in 1851 by a permanent cable of such excellent construction that it survived for a number of years. Several longer lengths of submarine cable were laid within the next few years. Italy was connected with Corsica and Sardinia, and Sardinia with Africa. A Black Sea cable was laid in 1835, but operated only a short time.
Thus far attempts to lay submarine tele lines had been confined to comparatively short distances. In 1858, after repeated un
successful experiments, telegraphic communi cation was established across the Atlantic. After something over a hundred messages had been sent back and forth, the cable to work. Al though this cable was a comparative failure, yet its brief success proved two things: (1) That a cable could be laid through 3000 miles of deep sea ; (2) that the electric current could be transmitted through a wire of that length. It was not until 1866 that a permanent cable was laid across the Atlantic. (The detailed history of this undertaking is described under ATLANTIC TELEGRAPH.) A second Atlantic cable was in ammrated immediately after, the one which had broken in the laying in 1865 having been re paired. In 1859, after the first Atlantic cable had ceased to work, the lied Sea and East Indian Telegraph was laid, over a route 3043 miles long, but this also proved a dismal failure and was finally abandoned. The Malta-Alexandria cable was laid in 1861, and was in use till 1872, when, from repeated breakages in shallow water, its was discontinued. The core consisted of a strand of seven copper wires, covered by three layers of gutta-percha ; outside of this was a serving of tarred yarn ; and, finally, IS iron wires constituted the sheathing. This was the first long cable suc cessfully laid (its total length, in three sections, being 1331 miles) and it was also the first properly tested under water before being laid, and carefully constructed with constant watch fulness as to its electrical and mechanical con ditions. In 1S69 a cable 2328 miles long was laid from. Brest. France. to the island of Saint-Pierre, south of Newfoundland ; in 1373. one from Lisbon to Pernambuco, Brazil. In 1874 a third British Atlantic cable was laid, from Ireland to New foundland, and in 1875 a fourth, from Ireland to New Hampshire. In 1903 there were 19 cables across the Atlantic, of which three were no longer in use. Of these, two distinct lines, one of which is duplicated, connect Europe with South America.
In 1902 the British Pacific Cable between Australia and British Columbia, 7S00 nautical miles in length. was completed, and in 1903 the first American cable was, laid across the Pacific, with a length of 7S46 nautical miles, by the Commercial Cable Company, between San Francisco and the Philippines, touching at Ha waii, Midway Island, and Guam. In 1903 the total length of submarine cable was estimated at over 250,000 miles, representing an outlay of Over $300,000,000.