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 102
uring their relative capacities (seeCondenser Testing). The Thomson galvanometer, prototype of the mirror orreflecting galvanometers, was invented by Lord Kelvin.Instead of employing a pointer, as in the galvanometersalready considered, a ray of light from a lamp is reflectedon to a scale placed…
Telegraph
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
