Signalling vs Heliograph - What's the difference?
signalling | heliograph |
the use of signals in communications, especially the sending of signals in telecommunications
(rail transport) the signals and associated equipment required for their operation.
An apparatus for signalling by means of a moveable mirror which reflects flashes of sunlight.
*1979 , (Alasdair Gray), ‘Five Letters From an Eastern Empire’, Canongate 2012 (Every Short Story 1951-2012 ), p. 93:
*:when we stood up at nightfall we saw, in the sunset, the sparkle of the heliograph above cities, on the far side of the horizon.
A heliogram.
An instrument for measuring the intensity of sunlight.
A device for photographing the sun.
(obsolete) A photograph.