Papers - literary, sicentific, &c. (1887) (14786266323)

Identifier: papersliterarysi02jenk (find matches)
Title: Papers : literary, sicentific, &c.
Year: 1887 (1880s)
Authors: Jenkin, Fleeming, 1833-1885 Colvin, Sidney, Sir, 1845-1927 Ewing, J. A. (James Alfred), Sir, 1855-1935
Subjects:
Publisher: London : Longmans, Green, and co.
Contributing Library: University of California Libraries
Digitizing Sponsor: MSN



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th a certainty that it will bedelivered without considerable delay and probable mutilation.Mr. Renter, to whom we owe the organisation of the despatchof public news, has begun to organise a system by which, intime, the great capitals of Europe may really be placed ininstantaneous communication. A Parliamentary Committeehas been considering proposals of a similar kind extended tothe East; but, meanwhile, a message sent through the AtlanticCable may be delayed five or six days in the wilds of NovaScotia, and mutilated messages continue to arrive after a fort-nights journey from India. So long as this is the case, nocalculation can be made of the employment which would befound for our gi-eat submarine cables if worthily worked. Butthe fact that much remains to do, even after the Atlantic Cablehas been laid, need not prevent a just pride in a really greatvictory, achieved, not by chance, but by a knowledge resultingfrom the patient efforts of many minds for many years. 248 APPLIED SCIENCE
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SUBMARINE TELEGRAPHY 249 ADDENDA. Explanation of Diagram of Shore Tests—Atlantic Expedition. S is a switch by which the cable can be connected at pleasurewith the studs 1, 2, and 3. The cable is always connected with Smiths resistance, throughwhich a feeble current passes, deflecting galvanometer G, and show-ing by its magnitude the state of insulation of cable, or, more strictlyspeaking, the potential at S. When S is connected with stud 1, as drawn, condenser 1 ischarged by the cable. It can be discharged through galvanometer G,.This discharge is a second test of the potential at S. It will cause anonward movement in the current applied by the ships battery, and aconsequent momentary change of deflection in the ships galvanometer.This will be a continuity test for the ship, proving the copper unbroken.This test might have been used as an arrangement for speaking fromshore to ship. Two condensers of different sizes would have given twosignals, from which an alphabet could be formed.