This introduction was written in February 1998
You are about to open the first great scientific book in history. Robert Hooke was still in his twenties when he wrote Micrographia, yet this single volume marks the beginning of serious scientific investigation. In it we are introduced to the living cell; to microscopic fungi and the life-story of the mosquito; we encounter the two contrasting theories about the origin of the lunar craters posed for the very first time. We read the first sensible proposal for the origin of fossils, and an uncanny prediction of the artificial-fiber industry. Hooke wrote of the spinning of silk by the spider, concluding with these far-sighted words: 'some Ingenious inquisitive Person [might] make some trials, which if they are successful, I have my aim, and I suppose he will have no reason to be displeas'd.'. Elsewhere in his great book, gigantic insects populate the pages, and controversy and scientific argument mark out the text.
Micrographia is a large book, measuring almost thirteen inches tall and weighing three pounds. It was printed in October 1664, and when bound copies appeared on sale it became an instant best-seller. Samuel Pepys - who owned a microscope in his time at the Navy Office - wrote that he liked Micrographia better than any other book he had bought, and sat up half the night reading its revelations. The first edition was dated 1665, and was printed with a two-colour title page (the key words picked out in red ink). The second followed in 1667, this time with the title page printed only in black. The book remained popular, and seventy years after it first appeared the plates (minus a few which had been lost or damaged) were reprinted for publication under the editorship of an amateur enthusiast and writer named Henry Baker. This new book was entitled Micrographia Restaurata with editions in 1745 and 1780. Plates from Hooke's original studies continued to reappear in the nineteenth century, and facsimiles of the original Micrographia have appeared in the twentieth century. Reduced versions in paperback mean that the book remains in print into the third millennium.
Most people cannot relish the crisp printing and the fine paper of an original issue from 1665, and this edition on CD-ROM brings the look of the first edition truly into the public domain. We can marvel at the clarity of the prose and the vividness of the pictures. Many of the plates (like that of the stinging nettle, for example, and the louse) have a vividness not regained until the era of the scanning electron micrograph. It is hard to believe that these are the images from a pioneer who flourished three and a half centuries ago.
Nobody knows what Robert Hooke looked like. Uniquely, for a major figure of his time, we have no portrait of the man. There are records which suggest a portrait was painted, and perhaps he was drawn too, but nothing is known to have survived to the present day. I would know him at once if I saw him, however. His manner seems to have been distinctive, for he had a small, hunched body and pale, darting eyes. His gait was urgent and he always walked quickly, giving an impression of boundless nervous energy. He remained constantly active and on the move to near the very end of his life.
Robert Hooke was born on July 18 1635 at Freshford on the Isle of Wight, a small island just off the south coast of England. He was a sickly child, too ill to go regularly to school, so he was educated at home by a father who taught him whenever he found spare time. The young Robert had a penchant for making scientific toys - clocks, model boats, sundials - and learnt enough Greek and Latin eventually to gain entrance to Westminster School, London, after his father died when Robert was just thirteen. The legacy he inherited was £100, a very modest sum with which to launch a career. Robert Hooke excelled at school in London, designing 'thirty different ways of flying', and is said to have mastered six books of Euclid in a single week. From Westminster he went up to Oxford University where he worked as an assistant to Thomas Willis and met the great Robert Boyle. He was soon acting as Boyle's research assistant at Boyle's private laboratory in the High Street, where he succeeded in perfecting a vacuum pump. These designs of Hooke's were later adapted by the developers of the first steam engines, from which the industrial revolution arose.
About this time emerged the Royal Society, which was destined to become Britain's 'academy of science'. It had its roots in the 'invisible college', an informal meeting-point for young philosophers in London and Oxford which emerged in 1645. By 1660 the Royal Society itself was formed, initially as a discussion group, but it was dignified by royal patronage in 1662 by King Charles II. Britain was emerging from its period as a republic under Oliver Cromwell, which had seen the execution of King Charles I, and the charter issued to the Royal Society by the newly restored monarch marked the beginning of a new era of scientific investigation. Robert Boyle was amongst the founder members of the new Society, and the fellows were so impressed by the young Hooke that they appointed him their Curator of Experiments in November 1662. This marked the beginning of his marvelously creative career. Microscopes were attracting interest. The design preferred by Hooke was made a tube of cardboard covered with finely tooled leather. Two glass lenses (an objective, and an eyepiece or field-lens) could reveal small details of familiar objects which were clearly a key to a greater understanding of the scientific world. Within four months of taking up his job, Hooke was given the specific responsibility of making microscopical demonstrations to the members of the Royal Society. This command came on March 25, 1663 and it launched him on a career that was to set science off in a new direction, and whose legacy remains with us today.
The first demonstration came two weeks later, on April 8 1663, and it is in many ways still the most unappreciated of them all. Hooke examined the tiny leaflets of a wall moss growing outside the Royal Society premises, and drew a meticulous study showing the plant in all its magnified intricacy. The plant is drawn larger than life, and the spore-containing capsule is also well portrayed. However, the upper center of the plate contains a crucial detail: the cellular structure of the leaflets is delicately drawn, each separate cell captured by the engraver's line. This was Hooke's first demonstration, and it included a vision of living cells. The term 'cell' was coined by Hooke - but not to describe the living cells visible in his moss specimen. To him, the cell was meant to signify a little square room. He used it to connote the microscopic structure of a section of cork. His study shows clearly that the solid cork is made up of tiny boxes. This was seen as explaining the properties Hooke observed in cork: that it was highly compressible, that it resisted becoming saturated with water, and was exceedingly light. In this way, Robert Hooke used the microscope to explain the physical properties of a familiar substance. His description is clear: '. . . these pores, or cells, were not very deep, but consisted of a great many little boxes . . .' To Hooke, the cell was a dead box and not a living entity. However, it is this coinage which we use to this day to denote the unit of life and it is fascinating to realise that the first drawing Hooke ever made (moss) had already disclosed the cellular structure of the living plant. The observation on cork was presented to the Royal Society the following week, by which time the fellows had already become acquainted with the cell. None of them, it seems, realised how important was the discovery.
A veritable cavalcade of discovery followed. After the demonstration of moss (April 8 1663) and cork (April 13) which he showed with samples of Kettering-stone, came leeches in vinegar and mould on leather (April 22), diamonds in a flint and a spider with six eyes (April 29), then female and male gnats (May 6). He set up the point of a needle, the head of an ant and a fly (May 20), pores in petrified wood and a male gnat (May 27), sage leaves (June 10), and petrified wood again on June 17. Next week, on June 24, Hooke was instructed to join forces 'with Dr Wilkins and Dr Wren' to accelerate the program of microscopical demonstrations. These men were important members of Hooke's circle of acquaintances: John Wilkins was the Bishop of Chester who served as Secretary of the Royal Society, whilst Christopher Wren was a physician, a pioneer of hypodermic injection, better known to us for his ventures into architecture (Saint Paul's cathedral, London, being certainly the best-known example). Early in the next month, on July 6 1663, Hooke was in Whitehall to demonstrate some of these exciting findings to King Charles II. By order of the King, his findings were to be collected together in the form of a commemorative book. After this further encouragement, Hooke's demonstrations continued apace: the edge of a razor, fine taffeta, and a millepede (July 8); fine lawn; gilt-edged paper and a feather-winged moth (July 16); sea-weed, teeth of a snail, a fungus on rose-leaves (August 5); and insects in rain-water (August 17).
The pace of work never slackened. During the following summer we may read in the Minutes that Robert Hooke 'was ordered to bring in two or three good experiments at the next meeting,' (June 1 1664) and 'Mr Hooke was desired to think upon one or two experiments more,' (June 29). If ever he was unable to attend a meeting, there were no experiments. He had become the mainstay of the Royal Society's scientific programme. And all the while, the idea of compiling his findings into a great book for public sale was forming in his mind. Robert Hooke was single-minded and businesslike when he set out to compile Micrographia. He enquired of the likely interest in the subject, and asked his scientific friends (including Christopher Wren) whether they knew of anyone else likely to write a competing book. Once he was satisfied that he could command the greatest market share he determined to make the contents of the book much broader than the title suggests. Hooke used the fashionable microscopic theme as a means of attracting public attention, but incorporated a range of his current theories and findings in order to establish a precedent in print.
The first Plate, for instance, shows Hooke's design for the mercury barometer. Instruments of this sort are widely used to this day. Plate IV deals with the behaviour of liquids in glass tubes, capillary action, and Prince Rupert's Drops (glass beads which burst violently when pinched). He then deals at length with the nature of light, and the existence of spurious colors in feathers and minerals. Hooke came into violent conflict with Newton, whom he later accused of plagiarising his ideas. By Plate VII Hooke is showing how the shape of crystals can be related to the packing of spherical molecules within them, an observation which helped set the new discipline of crystallography on a scientific footing. Only one of Hooke's original drawings seems to have survived. It is of ice crystals, and the engraved version features in Plate VIII. At the head of this plate is an array of snowflakes, and they - unlike the other images in the book - have an appearance which is not like that of snowflakes in nature. These flakes are caricatures of the real thing. I now find that the reason is simple: Robert Hooke was himself plagiarising the work of an earlier investigator. His figures are clearly taken from those published in 1661 by Thomas Bartholin in his De Nivus usu Medico Observationes Varieae. For all his protestations about contemporaries misappropriating his work, Robert Hooke was not above using another's images in his own great book on seventeenth-century science. He moves on to set out the origin of fossils in an explanation close to our modern understanding. Hooke describes his experiments with the beard of wild oat (which twists and turns with changes of humidity) and in Plate XV shows a design for a hygrometer which could harness the effect for scientific purposes. He returns to the refraction of light later in his book, devoting Plate XXXVII to the subject, before concluding with studies of the lunar craters and stars which he made with a telescope and publishes on Plate XXXVIII. He shows experimentally that the craters could be made either by upwelling from beneath, or bombardment from above; a controversy which has still been waged in recent years.
Robert Hooke was creative in many other fields of endeavor. He was a noted architect, and one of his surviving buildings may well be the Pepys Library at Cambridge University. Hooke also designed the monument to the great fire of London; it is often said that the designer was Christopher Wren, but the records show it was Hooke who designed this striking column. His work as a surveyor proved him to be a gifted architect. After the astronomical observations recorded in Micrographia, Hooke went on to draw surface features on Mars (these were used over a century later when observers timed that plant's period of rotation). He also was the first to propose that Jupiter revolves about its axis. He applied the inverse square law to the orbits of the planets, set out to show that the earth had an elliptical orbit, proposed the wave theory of light, and showed that the length of a spring is a function of the force applied to it. This is still known as Hooke's Law, and it is through this simple idea that schoolchildren encounter the name of this great man in the classes of today.
Brian J Ford is Chairman of the Committee for the History of Biology at the Institute of Biology in London and a Fellow of Cardiff University. He has written reference books and popular works on the development of the microscope, and is well known as a lecturer and broadcaster on radio and television. Among his recent titles are Images of Science, a History of Scientific Illustration and Single Lens, the Story of the Simple Microscope. He lives and works in Cambridgeshire, England.