This Month in Physics History

January 1665: Publication of Hooke's Micrographia

Hooke memorial window, St. Helen's, Bishopsgate, City of London. http://www.roberthooke.org.uk/

Few classic scientific publications have enjoyed the lasting impact of Isaac Newton's Principia or Charles Darwin's Origin of the Species, but one that is often neglected is the Micrographia. Its author, Robert Hooke, was one of the most brilliant and versatile of 17th century English scientists, albeit lesser known than his contemporary, Newton. Apart from its inarguable scientific importance, Micrographia opened up a hitherto invisible universe to the general reading public.

Born on the Isle of Wight to a curate, Hooke was initially destined to become an artist, apprenticed at 13 to the leading portrait painter of the age. But he complained that the oils and varnishes irritated his chest, and left to attend Westminster School, where he acquired mastery of ancient languages, learned to play the organ, experimented with flying machines, and is said to have mastered the first six books of Euclid's Elements in a week. In 1653 Hooke became a chorister at Christ Church, Oxford, where he met the men who would later found the Royal Society. In 1658 he became assistant to Robert Boyle, applying his mechanical skills to the constructions of an improved version of an airpump, and gaining a thorough mastery of chemistry and practical laboratory skills.

Four years later, Hooke was appointed curator of experiments to the newly founded Royal Society, responsible for the experiments performed at its weekly meetings. In 1665 he was finally hired as a professor of geometry at Gresham College, making him the first salaried research scientist in Britain. Between 1661 and 1664, he conducted a series of observations and experiments using a microscope which formed the basis for the Micrographia.

Micrographia first appeared in bookshops in January 1665 and had an immediate sensational impact. For scientists, it provided not only a wealth of new data but an articulate and beautifully presented justification for experimental science. For example, a simple observation of a piece of charcoal under the microscope could lead to a recognition of the presence of cells. The anatomical description of a fly developed into an experimental essay in aerodynamics, acoustics and wave patterns. Indeed, every one of the 60 observations in the Micrographia are detailed starting points for further physical investigations, accompanied by 58 stunning engravings. Hooke's artistic gifts proved essential to the realization of the work, enabling him to faithfully interpret and delineate the awkward images produced by the compound microscopes of the 1660s.

The book had an equally powerful impact on the laity, in large part because of the accessible writing style and ample illustrations, which offered an arresting new perspective on common and familiar objects: a fine needle point looked like a rough carrot, delicate silk looked like basket work, and extinguished sparks resembled lumps of coal. Samuel Pepys claimed he pored over the volume until 2 AM, declaring it "the most ingenious booke that ever I read in my life," and he later bought his own scientific instruments and joined the Royal Society, eventually becoming its president in 1684.

While Hooke's later work in optics and gravitation was overshadowed by the contributions of Isaac Newton, he was unsurpassed in his time as an inventor and designer of scientific instruments. For instance, he invented the spring control of the balance wheel in watches; the compound microscope; a wheel barometer; and the universal joint found today in all motor vehicles: the "Hooke's joint." He was among the first to insist on the importance of resolving power in astronomical instruments, and built the first reflecting telescope, using it to observe the rotation of Mars and note one of the earliest examples of a double star. And he was an accomplished architect, designing many London buildings, although only a few survive.

In his later years, Hooke's health deteriorated, and he suffered from numerous symptoms of cardiovascular disease and diabetes: swollen legs, chest pains, dizziness, emaciation and blindness. He died on March 3, 1703. While he enjoyed a measure of worldly success, his reputation suffered from his many controversies with other scientists, including one with Christiaan Huyghens over the spring regulator, and with Newton, first over a question of optics and later over priority in the formulation of the inverse square law of gravitation. Always prickly where his pride was concerned, he eventually grew embittered, melancholy and distrustful, feeling that he had been cheated by Newton of his proper eminence in society.

While Hooke never achieved the same recognition as Newton, he was nevertheless a figure of extraordinary and diverse creativity, combining a solid grasp of ancient languages, highly skilled draughtsmanship and practical craft skills. But most of all, according to Oxford University historian Alan Chapman, "He was the man who showed that the 'experimental philosophy' actually worked and could be used to extend the bounds of natural knowledge. He was Europe's last Renaissance man, and England's Leonardo."