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 100
Fi(i. 70. Q and I detector. explained previously. The case, which has a glass co^erunda small window to admit light upon the scale, is moveduntil the pointer is at zero and the magnet rests in themagnetic meridian. The P.O. instrument Avound to aresistance 800- produces a deflection of 10 divisions…
Telegraph
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
