What's the difference between helicograph and heliograph?

Helicograph

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Definition:

• (n.) An instrument for drawing spiral lines on a plane.

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Heliograph

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Definition:

• (n.) A picture taken by heliography; a photograph.
• (n.) An instrument for taking photographs of the sun.
• (n.) An apparatus for telegraphing by means of the sun's rays. See Heliotrope, 3.

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