Some signal lamps are mounted on the mastheads of ships, some small hand-held versions are also used ( e . g ., the'Aldis lamp'); other more powerful versions are mounted on pedestals.
12.
The contacts could operate an audio oscillator for the study of International Morse Code ( used by radio ), or a sounder for the study of American Morse Code ( used by railroads ), or a light bulb ( Aldis Lamp-used by Navy ship to ship or by Heliograph ).
13.
The findings were forwarded to the Commander in Chief, Grand Fleet, Admiral David Beatty, who remarked that the incident was " . . . one of those that are inseparable from war ", but deplored the delay in introducing improved signalling facilities on submarines, particularly the substitution of the slow, unreliable and cumbersome cruiser arc lamp with Aldis lamps.
