Hour circle for flag telegraphy. 19th-century book page showing signals and codes transmitted by use of flag telegraphy or semaphore signals. This pag

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Hour circle for flag telegraphy. 19th-century book page showing signals and codes transmitted by use of flag telegraphy or semaphore signals. This page shows an hour circle, used in conjunction with the time pennant to communicate times and periods of the day (outer circle). Such communication systems were used between ships until replaced by wireless telegraphy (radio). This page is from the second edition (1818) of 'An Improved System of Telegraphic Communication' by British naval officer Thomas Lynn (1774-1847).

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Size: 2923px × 3044px
Photo credit: © KING'S COLLEGE LONDON/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No

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