William Gilbert, English physician, late 16th century.
© Science Museum / Science & Society Picture Library
William Gilbert (1544-1603) established the magnetic nature of the Earth in 'De Magnete' (1600) and conjectured that terrestrial magnetism and electricity were two allied emanations of a single force. The first to use the terms 'electricity', 'electric force' and 'electric attraction', he also pointed out that amber is not the only substance which attracts light objects when rubbed. The Gilbert force of magnetomotive power is named after him.