'The Chinese Neptune' and 'Phenomena of the Natural Magnet', 1815.
© Science Museum / Science & Society Picture Library
Engraving by J Pass showing a Chinese deity, and apparatus used to demonstrate magnetism. When iron filings are placed near a magnet they become magnetised. They thus point in the same direction of applied magnetic field of the bar magnet. Illustration from 'Encyclopaedia Londinensis, or, Universal Dictionary of Arts, Sciences, and Literature' published in London, 1810-1829.