Compass with magnetic deviation. 19th-century illustration of magnetic deviation for a mariner's compass. This phenomenon is the change in the reading of a compass due to local magnetic fields,but can also refer to the difference between magnetic North and true North. The latter difference is more correctly known as magnetic declination. Artwork from 'A Short Treatise on the Deviation of the Mariner's Compass' (London,1849) by Arctic navigator John Ross (1777-1856) | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Royal Astronomical Society |
Taille de l’image : | 5020 px × 3839 px |
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