Abstract
IX. In all submarine cables the copper conductor is composed of seven small wires stranded together, an arrangement which gives much greater flexibility and strength than if a solid wire were employed. The general arrangement of the signal apparatus in connection with the cable is shown at Fig. 38. A, the battery, consists of a series of cells of Daniell's arrangement; B, the contact keys for passing the positive and negative currents into the cable; C, “switch,” placing the cable in connection either with the earth, instrument, or battery as required; D, a form of Sir William Thomson's reflecting galvanometer placed in connection with the cable by switch C; E, the permanent magnet arrangement for steadying and adjusting the coil-mirror (shown in section and detail, Fig. 39); I, resistance coils interposed into the circuit between the instrument and the earth; J, a switch for connecting the line to earth; F, a darkened recess to receive the scale upon which the spot of light reflected from the lamp situated behind the partition, the ray from which, passing through a slit in the direction R is reflected back from the galvanometer mirror in the direction R′; the spot of light moves to the right or left of the zero on the scale, according as a positive or negative current is passed through the circuit; the several signals being indicated by the successive oscillations of the luminous image, signals which correspond to the conventional alphabet of the Morse system. The Morse alphabet is given at Fig. 40.
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The Progress of the Telegraph * . Nature 12, 254–256 (1875). https://doi.org/10.1038/012254a0
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DOI: https://doi.org/10.1038/012254a0