signal mirror:
1911 Mechanical Semaphore
signal mirror:
Signalling by Mechanical Semaphore - British Navy
signal mirror:
Mechanical Semaphore - British Navy
signal mirror:
Two-Arm Mechanical Semaphore, British Navy
signal mirror:
1903 SIGNALLING BY SEMAPHORE
signal mirror:
1905 British Navy - Three Visual Signalling Methods (c.1)
signal mirror:
1905 British Navy - Three Visual Signalling Methods (c.2)
signal mirror:
1891 Mechanical Semaphore HMS Camperdown