HELIOGRAPH
heliograph
(noun) an apparatus for sending telegraphic messages by using a mirror to turn the sun’s rays off and on
heliograph
(verb) signal by means of a mirror and the using the sun’s rays
Source: WordNet® 3.1
Etymology
Noun
heliograph (plural heliographs)
An apparatus for signalling by means of a moveable mirror which reflects flashes of sunlight.
A heliogram.
An instrument for measuring the intensity of sunlight.
A device for photographing the sun.
(obsolete) A photograph.
Verb
heliograph (third-person singular simple present heliographs, present participle heliographing, simple past and past participle heliographed)
(transitive) To send a message by heliograph.
(intransitive) To send a heliograph.
(transitive, dated) To photograph by sunlight.
Source: Wiktionary
He"li*o*graph, n. Etym: [Helio- + -graph.]
1. A picture taken by heliography; a photograph.
2. An instrument for taking photographs of the sun.
3. An apparatus for telegraphing by means of the sun's rays. See
Heliotrope, 3.
Source: Webster’s Unabridged Dictionary 1913 Edition