ROYAL ASTRONOMICAL SOCIETY / SCIENCE PHOTO LIBRARY ROYAL ASTRONOMICAL SOCIETY / SCIENCE PHOTO LIBRARY
Halley's magnetic Atlantic chart. Chart of the Atlantic Ocean showing variations in compass readings, published in 1700 by the English astronomer, meteorologist and physicist Edmond Halley (1656-1742).In 1698 and 1699 Halley, most famous for his work on comets, was given command of a ship by King George III and told to record geographical variations in compass readings (the amount the horizontal alignment of the needle differs from geographical North) as a way for sailors to determine longitude. The lines, known as isogonic lines, show places where the magnetic variation is equal. For an updated map after 1744, see image C023/8607.
Model release not required. Property release not required.