When we all got back to camp, our General communicated by heliograph from a distant mountain top with his superiors. |
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A heliograph was a communications system consisting of two mirrors on a tripod used to flash signals with sunlight. |
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Later, runners, telegraph, semaphore, heliograph and line were used to communicate. |
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An earlier version of the heliograph known as the heliotrope was used during the American civil war. |
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During the First World War, signals troops transmitted messages by telephone, heliograph, semaphore and runner. |
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The prime instruments were the H-alpha telescope equipped with a Lyot filter and the white-light heliograph. |
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Organised divers always carry some means of signalling their position at the surface, whether it be air-horn or flag, flare or heliograph, or combinations of two or more. |
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Another instrument was added to the techniques for visual signaling through the development of the heliograph. |
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On my Arctic research trip in 2015, I used a heliograph – a device that was historically used to record the sun. |
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Because consistency and regularity of sunshine were important, the heliograph was never widely adopted throughout the armies of continental Europe. |
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In 1826, he had produced another heliograph, a reproduction of an engraved portrait, which was etched by the Parisian engraver Augustin-François Lemaître, who pulled two prints. |
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In England, the word was first presented in a lecture at the Royal Society, eventually winning out over its contemporary rivals photogene and heliograph. |
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