THE COAST SIGNAL STATIONS AND THE SEMAPHORE TELEGRAPH
The Mariner's Mirror ; 1 , 7 ; 161-166
01.01.1911
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Long's electrical Semaphore railroad signal
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The union electric semaphore signal
Engineering Index Backfile | 1902
Long's electrical Semaphore railroad signal
Engineering Index Backfile | 1888