The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 363
ementshown allows of the insulator being takenapart from the bolt, when in position, forthe purpose of cleaning out the inside, orto change the position of the wires on thepoles. An india-rubber ring, put over thescrew, is sometimes used to allow for thedifference in expansion by heat betweenthe…
Telephone
Internet Archive · Northeastern University Library · Public Domain Mark 1.0. Free to use for anything.
