| Show the la in 1880 1850 1 in m odem modem cables t the he core is always protected first by a serving of hemp or jute and then by an outer sheath of soft steel wires which are relied relie donto on to furnish the mechanical strength which the cable must have in order that it may stand the pulling about which it receives in laying and repairing but in the pioneer trial there was no idea of a protecting sheath the naked core was to be laid in the channel to form the first telegraph between england and france there Ther ewas was but a single wire of copper inside nowadays there is always a strand of several wires twisted together and this was covered with gutta percha so thickly as to bring the diameter to halt half ax an I 1 inch the covered wire was wound on an a great reel on the deck of a steam tug in I 1 dover harbor and after a number of preliminary trips the line was laid on aug 23 1850 lead sinkers were attached at every yards to carry the cable to the bottom for in the al absence sence of any heavy sheathing its specific gravity scarcely exceeded that of sea water the attempt was at once made to open communication but bu t though signals seemed to pass nothing could be made of them and mr smith records that the operators at each end were regretfully forced to the conclusion that those at the other end had been lunching not wisely but too well next day matters were worse no signals would pass at all the cable was broken and so ended this first attempt at submarine telegraphy the signals of the first day had been unintelligible not because of any breach of continuity on the part of the cable or failure in temperance on the part of its guardians but simply in consequence of electrostatic induction the influence of which in retarding the electric pulses was not then understood london saturday review |
