English: Fig. 1 and 2 from the plate on "Telegraph" in Rees's Cyclopædia, illustrating Robert Hooke's proposal for an optical telegraph system. For further explanatory text, see entry on "TELEGRAPH", volume 35 of the Cyclopædia.
The author died in 1851, so this work is in the public domain in its country of origin and other countries and areas where the copyright term is the author's life plus 100 years or fewer.
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This work is based on a work in the public domain. It has been digitally enhanced and/or modified. This derivative work has been (or is hereby) released into the public domain by its author, Morgan Riley. This applies worldwide.
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Captions
Illustration showing Robert Hooke's proposed system. At top are various symbols that might be used; ABCE indicates the frame, and D the screen behind which each of the symbols are hidden when not in use.
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