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 138
cal vessel fi-om which TELEGRAPH LINES 127 the air is exhausted, tlius extracting the greater part of themoisture from the timber, and hot creosote is forced intothe timber under pressure. About 10 lb. of creosote percubic foot of timber is necessary to insure good results. The dimensions of the… … Fii.;. 101.—Jointing of kirgc copiicr and iron wires. increased, but no general rule can be given for the heightof the lowest wire on a line, this being governed entirelyby local conditions. Poles are usually set at a distance of from 00 to 75 yardsapart, and on lines wdthout curves the span is…
Telegraph
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