Magnetic toy, 1765.
© Science Museum / Science & Society Picture Library
Magnets were used for amusement as well as navigation. This toy was made by George Adams, instrument maker to the king. If the box containing the windows was placed above the box containing the ebony pieces, the numbers in the windows corresponded to the numbers below on the ebony pieces. This is because the paper dials under the windows carry concealed magnets which align themselves with concealed magnets in the ebony pieces.