Engineering Wonders of the World
Volume I

294 ENGINEERING WONDERS OF THE WORLD. The magnet is artificially brought back to zero with great precision after each signal by the earth’s magnetism, as well as by the natural torsion of the fibre and the action of an adjusting magnet. The said adjusting magnet is readily regulated by a thumb-screw as required. In this highly efficient apparatus Professor Thomson turned to account the imponder- ability of light for magnifying the signals transmitted through a cable. The system was also adopted for testing purposes, and did good service in this respect, until the inventor introduced something better suited to the special requirements. Mr. Bright arranged for a preliminary ex- pedition on this occasion to rehearse the various operations to be performed during cable manoeuvres. These operations—per- formed in the Bay of Biscay—consisted of making splices, and of picking up and buoy- ing (as well as laying) cable in deep water. It was agreed that this time paying-out should start from mid-ocean; further, that the main cable should be buoyed at either end, and that connection with it by heavy cable from shore should be effected at the first favourable opportunity. (To be concluded.) Fig. 18.—This illustration gives a general view of the paying-out apparatus mounted on the deck of the Agamemnon. The gear gave complete satisfaction during the trial trip, when all the engineering operations were gone through successfully, and the electrical working of the entire cable was perfectly satisfactory throughout.