EXTRACTS OF PROCEEDINGS OF THE SOCIETY OF TELEGRAPH ENGINEERS.

RESEARCHES IN ELECTRIC TELEPHONY.

USEFUL BOOKS ON TELEGRAPHY, and c.

ENTITLED

RESEARCHES IN ELECTRIC TELEPHONY,

BY

PROFESSOR ALEXANDER GRAHAM BELL,

DELIVERED BEFORE

The Society of Telegraph Engineers,

October 31st, 1877.

PUBLISHED BY THE SOCIETY,
AND EDITED BY
LIEUT.-COL. FRANK BOLTON, C.E., Hon. Secretary,
AND
WILLIAM EDWARD LANGDON, Acting Secretary.

London:
E. and F. N. SPON, 46, CHARING CROSS.

New York:
446, BROOME STREET.
1878.

Price One Shilling and Sixpence.
The right of translation and reproduction is reserved