18th century map of the Northern Hemisphere with a dedication to George Washington, president of the USA. This is a magnetic atlas, or variation chart

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18th century map of the Northern Hemisphere with a dedication to George Washington, president of the USA. This is a magnetic atlas, or variation chart, that allows the magnetic variation of any location to be determined. The magnetic variation is the difference between true north and magnetic north, which varies with location and time. The map was drawn by the surveyor John Churchman (1753-1805) and first printed in 1790.

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Size: 4901px × 4996px
Photo credit: © AMERICAN PHILOSOPHICAL SOCIETY/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: -, 1700s, 1790, 18th, artwork, atlas, century, chart, churchman, declination, dedication, geographical, geography, geomagnetism, george, hemisphere, historical, history, illustration, inscription, john, magnetic, map, navigation, northern, plan, variation, washington