Some recent developments in telephony and telegraphy
By: By Frank B. Jewett ...
Language: eng
Subjects: Telephone; Telegraph
Notes: In Smithsonian institution. Annual report. 1915. Washington, 1916. 24 cm. p. 489-509.

"Read at the Second Pan American scientific congress, at Washington, Dec. 27, 1915-Jan. 8, 1916. Printed by permission of Executive committee of the congress."