Text-book of general physics, for the use of colleges and scientific schools (1899)
Hastings, Charles Sheldon · Boston: Ginn & company · leaf 498
eceiving instrument, or sounder, is placed in a localbattery circuit which is opened and closed by the lightlypivoted armature of an electromagnet called a relay andoperated by the current in the line wire. 442. Duplex Telegraphy. — In order to increase the work-ing capacity of a single line,… … G
Physics
Internet Archive · Public Domain Mark 1.0. Free to use for anything.
![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer04inte-172-61.webp)
![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer01inte-202-83.webp)
