An elementary book on electricity and magnetism and their applications (1919)
Jackson, Dugald C. (Dugald Caleb), 1865-1951, Jackson, John Price, b. 1868, Black, Newton Henry, b. 1874 · New York, The Macmillian Co · leaf 595
s (50to 100 is the usual numberper operator), a great manyboards of the kind describedwould be required in thelarger exchanges, and much difficulty and waste of time wouldbe experienced in making connections between the line of asubscriber connected to one board and the line of a… … Fig. 385. — Simple form of switchboardfor small exchanges. THE TELEPHONE 531 SUBSCRIBERS
Electricity · Magnetism
Internet Archive · Public Domain Mark 1.0. Free to use for anything.
![An illustration from Telephones and telegraphs: 1902 : [and Municipal electric fire alarm and police patrol systems] (1906)](https://img.insideoutlibrary.com/img/200/ia-cu31924022817674-82-33.webp)
![An illustration from Telephones and telegraphs: 1902 : [and Municipal electric fire alarm and police patrol systems] (1906)](https://img.insideoutlibrary.com/img/200/ia-cu31924022817674-82-34.webp)
![An illustration from [New illustrated catalogue of furniture and general price list] (1875)](https://img.insideoutlibrary.com/img/200/ia-newillustratedca00lave-98-254.webp)
