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Duplicate Signals at the Baltimore Observatory


Watercolor, ink, and pen on paper of "Duplicate Signals at the Baltimore Observatory," ca. 1818-1819, by an unknown artist. In 1797, U.S. Navy Captain David Porter (1780-1843) established a wooden marine observatory and watch tower on Federal Hill in Baltimore in order to alert merchants and ship owners of arriving ships. Around 1880, the original tower was replaced until a 1902 storm destroyed the tower. The U.S. flag, depicted top left, has twenty stars and twenty stripes. This was an unpopular design change that attempted to add a stripe for each additional state. The twenty star flag was adopted in 1818 and lasted only one year before the design was changed and thirteen stripes were restored.



circa 1818-1819


Watercolor, ink, and pencil on paper


9.375 x 13 inches

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Credit Line

Gift of Samuel T. Thompson

Digital Publisher

Digital resource provided by the Maryland Center for History and Culture


This digital image is made available here for private study, scholarship, and research. Commercial and other uses are prohibited without the permission of the Maryland Center for History and Culture. For more information, visit the MCHC’s Reproductions and Permissions web page.