Elementary telegraphy : a manual for students; written specially to meet the requirements of the ordinary grade of the subject as published in the syllabus of the city and guilds of London Institute (1910)
Pendry, H. W. (Henry Walter) · London ; New York : Whittaker & Co. · leaf 77
to the free ends of the armatures. Themagnetic condition of the armatures and cores is indicatedin the figure ; the latter have a permanent polarity equalto the magnetic effect of 18 m.a. of current, and if thearmatures are exactly central, equal attraction is exerted,but a very slight displacement… … B wiiidiii the current ceases the tongue returns to the spacingcontact. A positive current entering at (U) will strengthenthe polarity of the right-hand core and Aveaken the left-hand or, if strong enough, reverse it. The attraction andrepulsion of the four jDolepieces tend to make the relayvery…
Telegraph
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
