Semaphore

Semaphore, a name applied to the mechanism employed for telegraphing purposes prior to the discovery of the electric telegraph; invented in 1767 by Richard Edgeworth, but first extensively used by the French in 1794, and afterwards adopted by the Admiralty in England; consisted at first of six shutters set in two rotating circular frames, which, by opening and shutting in various ways, were capable of conveying sixty-three distinct signals; these were raised on the tops of wooden towers erected on hills; later a different form was adopted consisting of a mast and two arms worked by winches. The speed at which messages could be transmitted was very great; thus a message could be sent from London to Portsmouth and an answer be received all within 45 seconds. The railway signal now in use is a form of semaphore.

Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)

Selwyn, George Augustus * Semele
Selby
Selden, John
Selene
Self-denying Ordinance
Selim I.
Seljuks
Selkirk
Selkirkshire
Selwyn, George
Selwyn, George Augustus
Semaphore
Semele
Seminoles
Semipalatinsk
Semi-Pelagianism
Semiramis
Semiramis of the North
Semiretchinsk
Semitic Races
Semmering
Sempach