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Robert Hooke

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Robert Hooke, FRS (July 18, 1635 – March 3, 1703) was an English polymath who played an important role in the scientific revolution, through both experimental and theoretical work. His father was John Hooke curate of the Church of All Saints, Freshwater.

Born in Freshwater on the Isle of Wight, Hooke received his early education on the Isle of Wight and, from about the age of 13, at Westminster School under Dr. Busby. In 1653, Hooke secured a chorister's place at Christ Church, Oxford. There he met the chemist (and physicist) Robert Boyle, and gained employment as his assistant. It is possible that Hooke formally stated Boyle's Law, as Boyle was not a mathematician.

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 which were called "cellula". He is often credited with the discovery of the cell, though his microscope was very basic. The hand-crafted, leather and gold-tooled microscope Hooke used to make these observations for "Micrographia," is on display at the National Museum of Health and Medicine in Washington, DC. Also in 1665 he gained appointment as Professor of Geometry at Gresham College.

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

He died in London on 3 March 1703 (ns). He amassed a sizeable sum of money during his career in London, which was found in his room at Gresham College after his death. He never married.

It seems that no authenticated portrait of him survives. In 2003 the historian Lisa Jardine claimed a recently discovered portrait represents Robert Hooke. However, Prof. Jardine's hypothesis was soon disproved by Prof. William Jensen (University of Cincinnati) and independently by the German researcher Andreas Pechtl (Johannes Gutenberg University, Mainz). Actually, the portrait represents Jan Baptist van Helmont. A seal used by Hooke displays an unusual profile portrait of a man's head, that some have argued portrays Hooke. Both these claims remain in dispute, however. Moreover, the engraved frontispiece to the 1728 edition of Chambers' Cyclopedia shows as an interesting detail the bust of Robert Hooke.

Achievements

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. In February 2006, a long-lost copy of Hooke's handwritten notes from several decades' Royal Society meetings was discovered in a cupboard in Hampshire, and the balance-spring controversy appears by evidence contained in those notes to be settled in favor of Hooke's claim.

A flea from Hooke's Micrographia

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. Hooke's microscopes achieved no more than 30x magnification, which is insufficient to resolve the fine structural details in the insects, etc., that he engraved. Research by Brian J. Ford has shown that Hooke used a single-lensed 'simple' microscope to observe such things.

Leeuwenhoek took Hooke's inspiration and used similar microscopes to those Hooke described to discover his world of animalcules. Robert Hooke was later asked to confirm Leeuwenhoek's findings. He found simple microscopes tiresome to use, and once called his compound microscopes "offensive to my eye" and "much strained and weakened the sight".

Hooke's other significant achievements include the construction of the first Gregorian reflecting telescope, the law of elasticity, 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 also experimentally demonstrated the inverse-square law of gravity, but did not prove it mathematically.

Hooke has been described as London's Leonardo (Bennett 2003) because of the breadth of his interests and the volume of his output which included not only science but architecture, surveying, town planning and invention.

Some of Hooke's significant achievements in science

  • First to refer to cells in living matter. 1665: Robert Hooke discovers cells in cork, then in living plant tissue using an early microscope.
  • First to study fossils and hypothesise that they were extinct species.
  • First to report Jupiter's Red Spot and by observing it deduce that the planet rotated.
  • First to report the rotation of Mars.
  • Worked out the number of vibrations of each musical note.
  • Observed Lunar craters.
  • Published the first book on microscopy, Micrographia.
  • First to explain the shape of crystal in terms of the packing of their component parts.
  • One of the first to observe a binary star.
  • Postulated a wave theory of light, rejected by Newton and not re-established until about 1820 by Fresnel.
  • Advocated the medicinal use of Indian Hemp.
  • Proposed the inverse square relationship for gravity.
  • Proposed to Newton the idea that planetary motion was a combination of linear and circular motion. It is this that is far more important for Newton's work than the inverse square law.
  • Devised Hooke's law of springs and stretching.
  • His investigations into combustion that came close to discovering oxygen 100 years before Lavoisier.

Inventions

Like many scientists of the Early Modern era Hooke was also a prolific inventor. Some of Hooke's inventions that are still in use:

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. (Hooke, unlike many others, had been able to reproduce Newton's prism experiments and so spoke with some authority.) 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. He had probably discovered the relationship before 1660 but lacked the mathematical ability to formally prove it. When Newton published his Philosophiae Naturalis Principia Mathematica in 1687, including a proof of an inverse square law, he failed to credit Hooke at all despite initially having included acknowledgement of Hooke in the manuscript.

It is possible that this dispute may be overplayed: Gunther suggests that the two men held each other in some regard until quite late, citing as evidence their correspondence over matters such as the inverse-square law of gravitation, which Hooke (an undoubtedly gifted experimenter) had demonstrated. On the other hand Newton appears to have delayed publication of his Opticks until after Hooke's death for fear of Hooke's reaction to its contents.

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 this has been interpreted as a sarcastic remark directed against Hooke. This is somewhat speculative: Hooke and Newton had exchanged many letters in tones of mutual regard, and Hooke was not of particularly short stature, although he was of slight build and had been afflicted from his youth with a severe stoop.

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, as well as documenting "Newton's rings" before Newton did.

Newton's animosity towards Hooke extended to the removal of Hooke's portrait in the Royal Society and an attempt (prevented) to have Hooke's papers in the Society burned. Some have argued that Hooke's own unsympathetic character was also a factor: his diary shows that he did have uncomplimentary words for a number of the men he worked with, and was long in dispute with Huygens. Inwood (2002) points out that Hooke enjoyed a very active social life in the coffee houses of London and was known to have many close friends such as Christopher Wren. On this basis he appears to have been far more sociable and gregarious than Newton who spent much of his life as an academic recluse in Cambridge.

Hooke the architect

The church at Willen, Milton Keynes

Robert Hooke was an important architect. He was the official London Surveyor after the Great Fire of 1666, surveying about half the plots in the city. 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 parish church at Willen, Milton Keynes (historical Buckinghamshire).

Hooke's collaboration with Christopher Wren was particularly fruitful and yielded 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. (Hooke was in demand to use his competence as a surveyor and tact as an arbitrator to settle many of these disputes.) So London was rebuilt along the original mediaeval streets. It is interesting to note that much of the modern-day curse of congestion in London has its origin in these petty disputes of 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 cycle.

Books

See also

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