Hooke , Robert

(1635–1703) English physicist

Hooke, whose father was a clergyman from Freshwater on the Isle of Wight, was educated at Oxford University. While at Oxford he acted as assistant to Robert Boyle, constructing the air pump for him. In 1662 Boyle arranged for Hooke to become first curator of experiments to the Royal Society. There he agreed to “furnish the Society every day they meet with three or four considerable experiments.” Even though the society only met once a week the pressure on Hooke was still great and may explain why he never fully developed any of his ideas into a comprehensive treatise. He was also something of an invalid.

Hooke made numerous discoveries, perhaps the best known being his law of elasticity, which states that, within the elastic limit, the strain (fractional change in size) of an elastic material is directly proportional to the stress (force per unit area) producing that strain. He was the first to show that thermal expansion is a general property of matter. He also designed a balance spring for use in watches, built the first Gregorian (reflecting) telescope, and invented a number of scientific instruments including the compound microscope and the wheel barometer.

In 1665 he published his main work Micrographia(Micrography), which was an account – fully and beautifully illustrated – of the investigations he had made with his improved version of the microscope. It also contained theories of color, and of light, which he suggested was wavelike. This led to one of the major controversies – over the nature of light and the priority of theories – that he had with Isaac Newton. The other conflict was over the discovery of universal gravitation and the inverse square law. It is true that Hooke had revealed, in a letter to Newton in 1680, that he had an intuitive understanding of the form the inverse square law must take. Newton's reply to Hooke's charge of plagiarism was to distinguish between Hooke's general intuition that may have been well founded, and his own careful mathematical treatment of the law and detailed working out of its main consequences.

Hooke was also a capable architect, having written on the theory of the arch and designed parts of London after the great fire of 1666.