The Encyclopedia britannica; a dictionary of arts, sciences, and general literatureWith new maps, and original American articles by eminent writersWith American revisions and additions, bringing each volume up to date . iron shoe,1 shaped to concentratethe lines of force andthus produce a strongmagnetic field in thespaoe within which thesign»l-coi] is juspendedInstruments ifkind have beenmade to workboth with andwithout electrifi-cation of the ink. iVithont electrifi- ^- 81--8iplon recorder., cation the instrument (see fig. 31) is very simple and compact, andcapable of doing good work on cable
The Encyclopedia britannica; a dictionary of arts, sciences, and general literatureWith new maps, and original American articles by eminent writersWith American revisions and additions, bringing each volume up to date . iron shoe,1 shaped to concentratethe lines of force andthus produce a strongmagnetic field in thespaoe within which thesign»l-coi] is juspendedInstruments ifkind have beenmade to workboth with andwithout electrifi-cation of the ink. iVithont electrifi- ^- 81--8iplon recorder., cation the instrument (see fig. 31) is very simple and compact, andcapable of doing good work on cables 600 or 600 miles long. Whenconstructed for electrification of the ink they are available for muchgreater lengths, but for cables such as the Atlantic the original formIS still used. The strongest magnetic field hitherto obtained bypermanent magnets (of glass-hard steel) is about 3000 Witnthe electromagnets used in the original form of siphon recorder amagnetic field of about or over 5000 is easily obtained. shows a facsimile of part of a message received and recorded bya siphon recorder, such as that of fig. 30, from oneo^the EasternTelegraph Comnanys cables aboot 830 miles long,. (4) The automatic cnil* .scndov was ilcsigncJ by Sji \V. Thomson Anupfor the purposo of tlic cMcct of iiidui;tivc enibarrass- maUement ill long cables.* ,In hanJsciuliiig the end of llie curbcable is put to one or the other pole of the battery and to earth sender,alternately, tlio relative time dujiiig which it is to ajul toearth depending to a greatextcnt ontho opci-atoi.^ IJy tlio auto^ «, o e c u p I e 3 a ix S n t f\r m e d La t e )p^ iFio. 32.—Facsimile of siphon Tceordcr message- matic curb sender the cable is put to one or the other pole of thebattery and then to the reverse pole, for definite proportionatetimes during each signal. The cable is tluis charged first positivelyand then negatively, or vice versa, for each signal. This m
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Keywords: ., bookcentury1800, bookdecade1890, bookidencyclopedia, bookyear1892
