第30章

The recorder was first used experimentally at St. Pierre, on the French Atlantic cable, in 1869. This was numbered 0, as we were told by Mr.

White of Glasgow, the maker, whose skill has contributed not a little to the success of the recorder. No. 1 was first used practically on the Falmouth and Gibraltar cable of the Eastern Telegraph Company in July, 1870. No. 1 was also exhibited at Mr. (now Sir John) Pender's telegraph soiree in 1870. On that occasion, memorable even beyond telegraphic circles, 'three hundred of the notabilities of rank and fashion gathered together at Mr. Pender's house in Arlington Street, Piccadilly, to celebrate the completion of submarine communication between London and Bombay by the successful laying of the Falmouth, Gibraltar and Malta and the British Indian cable lines.' Mr. Pender's house was literally turned outside in; the front door was removed, the courtyard temporarily covered with an iron roof and the whole decorated in the grandest style.

Over the gateway was a gallery filled with the band of the Scots Fusilier Guards; and over the portico of the house door hung the grapnel which brought up the 1865 cable, made resplendent to the eye by a coating of gold leaf. A handsome staircase, newly erected, permitted the guests to pass from the reception-room to the drawing-room. In the grounds at the back of the house stood the royal tent, where the Prince of Wales and a select party, including the Duke of Cambridge and Lady Mayo, wife of the Viceroy of India at that time, were entertained at supper. Into this tent were brought wires from India, America, Egypt, and other places, and Lady Mayo sent off a message to India about half-past eleven, and had received a reply before twelve, telling her that her husband and sons were quite well at five o'clock the next morning.

The recorder, which was shown in operation, naturally stood in the place of honour, and attracted great attention.

The minor features of the recorder have been simplified by other inventors of late; for example, magnets of steel have been substituted for the electro-magnets which influence the swinging coil; and the ink, instead of being electrified by the mouse-mill, is shed on the paper by a rapid vibration of the siphon point.

To introduce his apparatus for signalling on long submarine cables, Sir William Thomson entered into a partnership with Mr. C. F. Varley, who first applied condensers to sharpen the signals, and Professor Fleeming Jenkin, of Edinburgh University. In conjunction with the latter, he also devised an 'automatic curb sender,' or key, for sending messages on a cable, as the well-known Wheatstone transmitter sends them on a land line.

In both instruments the signals are sent by means of a perforated ribbon of paper; but the cable sender was the more complicated, because the cable signals are formed by both positive and negative currents, and not merely by a single current, whether positive or negative. Moreover, to curb the prolongation of the signals due to induction, each signal was made by two opposite currents in succession--a positive followed by a negative, or a negative followed by a positive, as the case might be.

The after-current had the effect of curbing its precursor. This self-acting cable key was brought out in 1876, and tried on the lines of the Eastern Telegraph Company.

Sir William Thomson took part in the laying of the French Atlantic cable of 1869, and with Professor Jenkin was engineer of the Western and Brazilian and Platino-Brazilian cables. He was present at the laying of the Para to Pernambuco section of the Brazilian coast cables in 1873, and introduced his method of deep-sea sounding, in which a steel pianoforte wire replaces the ordinary land line. The wire glides so easily to the bottom that 'flying soundings' can be taken while the ship is going at full speed. A pressure-gauge to register the depth of the sinker has been added by Sir William.

About the same time he revived the Sumner method of finding a ship's place at sea, and calculated a set of tables for its ready application.

His most important aid to the mariner is, however, the adjustable compass, which he brought out soon afterwards. It is a great improvement on the older instrument, being steadier, less hampered by friction, and the deviation due to the ship's own magnetism can be corrected by movable masses of iron at the binnacle.

Sir William is himself a skilful navigator, and delights to cruise in his fine yacht, the Lalla Rookh, among the Western Islands, or up the Mediterranean, or across the Atlantic to Madeira and America. His interest in all things relating to the sea perhaps arose, or at any rate was fostered, by his experiences on the Agamemnon and the Great Eastern.