Magnetic Variation

What is equal magnetic variation? Here is a brief scientific history on the mapping of the earth’s magnetic field. Compiled from four maps in our collection, these pieces all show lines of magnetic variation across the Indian Ocean and were published between 1772 and 1882.


Magnetic Variation


For those also interested in the maps themselves, they are described below proceeding clockwise:

1772 World map on the mercator projection showing magnetic waves, published in Amsterdam by Willem Bachiene. View on our website

1798 The lines of magnetic variation in the seas around Africa, published in London by Rennell. View on our website

1867 British Admiralty chart of the world showing the curves of equal magnetic variation, published in London for the Admiralty Office. View on our website

1882 Chart of the Indian Ocean, published in London by James Imray. View on our website



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