Robert Hooke

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Robert Hooke, FRS (July 18, 1635 - March 3, 1703), one of the greatest experimental scientists of the seventeenth century, played an important role in the scientific revolution.

Born in Freshwater on the Isle of Wight, Hooke received his early education at Westminster School. In 1653, Hooke won a place at Christ Church, Oxford. There he met Robert Boyle, and gained employment as his assistant. In 1660, he discovered Hooke's law of elasticity, which describes the linear variation of tension with extension in an elastic spring. In 1662, Hooke gained appointment as Curator of Experiments to the newly founded Royal Society, and took responsibility for experiments performed at its meetings. In 1665 he published a book entitled Micrographia, which contained a number of microscopic and telescopic observations, and some original biology. Indeed, Hooke coined the biological term cell -- so called because his observations of plant cells reminded him of monks' cells. Also in 1665 he gained appointment as Professor of Geometry at Gresham College.

Robert Hooke also achieved fame as the chief assistant of Christopher Wren, helping to rebuild London after the Great Fire in 1666. He worked on designing the Royal Greenwich Observatory and the infamous Bethlem Royal Hospital (which became known as 'Bedlam').

He died in London in 1703. No authenticated portrait of him survives, although the historian Lisa Jardine claims one portrait of John Ray represents Robert Hooke, and a seal used by Hooke displays a man's head that some have argued portrays Hooke. Both these claims remain in dispute, however.

Achievements

File:HookeFlea01.jpg
A flea - one of Hooke's drawings for Micrographia.

In addition to the book Micrographia and Hooke's Law, Hooke invented the anchor escapement and may also have invented the balance spring before Christiaan Huygens. Devices known as escapements regulate the rate of a watch or clock, and the anchor escapement represented a major step in the development of accurate watches. The balance spring also regulates the flow of energy from the mainspring of a timepiece. It coils and uncoils with a natural periodicity, allowing for fine adjustment of the period of ticks. Modern spring watches still use balance springs, and derivative designs of Hooke's anchor escapement remain in common use.

Historians sometimes credit Hooke with inventing the compound microscope, a design consisting of multiple lenses (usually three - an eyepiece, a field lens and an objective). While he did give much advice on new microscope designs to the instrument-maker Christopher Cock, this attribution appears incorrect, since Zacharias Janssen had already assembled compound microscopes in 1590. However, Hooke's microscopes achieved 30x magnification, which far outstripped the capabilities of any previous instruments.

Hooke's other significant achievements include the construction of the first Gregorian reflecting telescope and the discovery of the first binary star. He also receives credit with inventing the first practical universal joint, sometimes called the Hooke joint, although the Italian mathematician Girolamo Cardano had proposed the idea about a century earlier and may or may not have built one.

Hooke and Newton

Robert Hooke and Isaac Newton entertained a considerable mutual dislike for each other. They fell out in 1672 when Hooke criticized Newton's presentation showing that prisms split white light rather than modifying it. Newton expressed fury that Hooke seemed unable to grasp his ground-breaking discovery, and threatened to leave the Royal Society.

Relations between the men grew worse as time progressed. In 1679, Hooke wrote to Newton advocating an inverse square law of gravitation, though he lacked the mathematical ability to formally prove it. When Newton published his Principia Mathematica in 1687, including a proof of an inverse square law, he failed to credit Hooke at all.

The famous Newton quote, "If I have seen further, it is by standing on the shoulders of giants", appeared originally in a letter to Hooke, and Newton presumably intended it as a sarcastic remark directed against Hooke, who had a remarkably short stature.

Part of the problem was caused by Newton's retreat to Cambridge during the years around the Plague and Great Fire. Hooke remained in London, demonstrating regularly at the Royal Society, while Newton's work often took longer to reach the Society. At a time when science was progressing by leaps and bounds it was inevitable that two men with such similar interests would come up with similar ideas. Whether Hooke or Newton first invented the reflecting telescope is a matter of conjecture, but it is the case that Hooke did demonstrate what is now known as the Newtonian telescope some time before Newton is credited with inventing it.

Newton's animosity towards Hooke extended to the removal of Hooke's portrait in the Royal Society (long believed destroyed but recently discovered) and an attempt (prevented) to have Hooke's papers in the Society burned. It is largely thanks to Newton that Hooke's name remained relatively unknown until the latter part of the 20th Century, although Hooke's own unsympathetic character was undoubtedly also a factor.

Hooke the architect

File:Willen-church-backlit.jpg
The church at Willen, Milton Keynes (backlit by morning sun)

Robert Hooke was an important architect. He was the official London Surveyor after the Great Fire of 1666. As well as the Bethlem Royal Hospital, other buildings designed by Hooke include: The Royal College of Physicians (1679); Ragley Hall in Warwickshire; and the church at Willen, Buckinghamshire.

Hooke's collaboration with Wren was particularly fruitful and yielded and The Royal Observatory at Greenwich, The Monument (to the Great Fire) and St Paul's Cathedral, whose dome uses a method of construction conceived by Hooke.

In the reconstruction after the Great Fire, Hooke proposed redesigning London's streets on a grid pattern with wide boulevards and arteries along the lines of the Champs-Élysées, (this pattern was subsequently used for Liverpool and many American cities), but was prevented by problems over property rights. Many property owners were surreptitiously shifting their boundaries and disputes were rife. So London was rebuilt along the original mediaeval streets. It is interesting to note that the modern-day curse of congestion in London has its origin in petty disputes in the 17th Century.

Mass Media

Robert Hooke is one of many real-life personages featured in the historical adventure novels The Baroque Cycle by American author Neal Stephenson; Hooke's skill in the sciences and surgical arts are used to great (and often darkly comedic) effect throughout the trilogy.

Books

  • Early Science in Oxford vol vii, Dr. R. T. Gunther, ed., privately printed, 1923-67.
  • Robert Hooke, Margaret 'Espinasse. William Heinmann Ltd, 1956.
  • The Curious Life of Robert Hooke: The Man who Measured London, Lisa Jardine. Harper Collins Publishers, 2003. ISBN 0007149441.
  • London's Leonardo: The Life and Work of Robert Hooke, Jim Bennett, Michael Cooper, Michael Hunter and Lisa Jardine. Oxford University Press, 2003. ISBN 0198525796.
  • England's Leonardo: Robert Hooke and the Seventeenth-century Scientific Revolution, Allan Chapman. Institute of Physics Publishing, 2004. ISBN 0750309873.
  • Robert Hooke and the English Renaissance, Allan Chapman and Paul Kent (editors). Gracewing, 2005. ISBN 0852445873.

External links

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