=Early Submarine Telegraphy.=--The actual date of the beginning of subaqueous telegraphy was admitted by Professor Ayrtoun, in a lecture delivered before the Imperial Institute in 1897, to be uncertain. Baron Schilling is said to have exploded mines under the Neva by means of the electric current as early as 1812; and this method was used by Colonel Pasley to blow up the wreck of the Royal George at Spithead in 1838; but our Morse has the credit of having first used a wire insulated with India rubber under water. In 1837, Wheatstone and Cooke were experimenting with land telegraphy, and were considering the possibility of laying an insulated wire under water. Morse's successful experiments date from 1842, when he personally laid a cable between Castle Garden and Governor's Island and sent messages over it; the next morning it was broken. With the introduction of gutta percha as an insulator in 1847, submarine telegraphy became practicable. The Central Oceanic Telegraph Company had been registered by Jacob Brett in 1845, and a cable was laid under the English Channel by Brett and his brother in 1850. Messages were sent through it, but, like Morse's earlier effort, it immediately became silent. Better success attended the cable of the next year, which was sheathed with iron; and the first public submarine message was sent over it November 13, 1851. Morse wrote of the possibility of establishing electro-magnetic communication across the ocean as early as 1844. A syndicate was formed for this purpose in 1855, Cyrus W. Field being the most conspicuous figure in it. An understanding was reached with the Brett company, and the Atlantic Telegraph Company was formed. The first effort to lay the cable was made in 1857 by the United States frigate Niagara and H.M.S. Agamemnon, but the wires broke in deep water when about a third of the work was done. A cable was successfully laid the next year, but it died out in a month. Finally, electric communication was permanently established across the Atlantic by the Telegraph Construction and Maintenance Company, which, capturing a cable that had been lost, soon had two. Transatlantic cables have now become so numerous and so regular in their working that the danger of even a temporary failure has become very remote.