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 150
nd stress :— Where I = length of span in feet. %v = weight of one foot in lbs.s = stress in lbs.d — dip or sag in feet. Lines are numbered as shown in sketch Fig. 119. Whena wire is run on a saddle it is invariably known as o, thenlooking at the up side of the pole—that is the si(]e facingthe… … Pig. 117.—Aerial cable suspension fZ = Pw8 s 140 ELEMENTARY TELEGRAPHY possible xxnder the footAvay upon the roads at a depth oftwo feet. Flush boxes were provided at distances of 100yards or less apart.
Telegraph
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
