'Magnetising an iron rod', 1600.

Engraved plate from William Gilbert's book 'De Magnete' ('On Magnets'), published in 1600, showing a man hammering iron on an anvil. Gilbert (1544-1603) was Queen Elizabeth I's physician and a leading English scientist of his day, investigating magnetism and popularizing experimenation to prove theories. In 'De Magnete', he established the magnetic nature of the earth, conjecturing that terrestrial magnetism and electricity were two allied emanations of a single force. He was the first to use the term 'electricity'.