Another huge leap forward along the path to unification took place almost two centuries after Newton, when James Clerk Maxwell showed that electricity and magnetism are in fact different facets of the same electromagnetic force. So, the electrostatic attraction between a scrap of paper and a balloon that has been rubbed on your clothing has its origin in the same electromagnetic force that attracts a paper clip towards a magnet. Almost all phenomena we see in nature are due ultimately to one or other of these two forces: gravity and electromagnetism. It was therefore natural to ask whether we
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