Meetings were held at Gresham College, a foundation established by the will of the Elizabethan financier Sir Thomas Gresham at his mansion between Broad Street and Bishopsgate, where seven professors were given lodgings and a salary in exchange for delivering free public lectures. Christopher Wren was Professor of Astronomy and Robert Hooke eventually became Professor of Geometry. The Lectures were often poorly attended by the public, Robert Hooke noted in his diary ‘ 12 June 1673 ‘No auditory came morning or afternoon so I read not....’ 1677 ‘no lecture but a rusty old fellow walked in the hall from 2 until almost 3..‘ 1678 ‘Only one came, peeped into the hall but stayed not’. However, whilst at Oxford, Hooke established his reputation for being adept at the construction of mechanical devices and the ability to design and carry out convincing experiments. In 1662 he was appointed Curator of Experiments for the Royal Society, and Gresham College became a significant meeting place for scientific discussion and research. Gresham College became Hooke,s home until his death in 1703. His task as curator was to supply each weekly meeting “with three or four considerable experiments” in addition to carrying out specific enquiries as directed by individual members of the Society.
These demands were very demanding to achieve and it is most likely that the Royal Society would not have survived without the impetus of Hooke’s experiments, lectures and discussions. From 1662 Hooke was at his inspiring best by stimulating many gentlemen to pursue natural philosophy as a subject worthy of study for its own sake. Topics ranged from combustion and respiration to geology, taking in magnetism, astronomy, microscopes, optics, horology, the mechanical behaviour of materials and much more besides.
Hooke died on 23rd March 1703 his funeral at St Helen’s Bishopsgate was attended by the whole membership in a mark of respect.
In a discussion of the structure of cork Hooke introduces the term “cell” to science and in addition to natural history he also considers the following areas of study:-
In 1676 Hooke announced his discovery in anagram form as “cediinnoopsssttuu” and two years later in De Potentia Restitutiva explained it as “Ut Pondus sic Tensio ie. “the weight is equal to the tension”.
His finding from an inspection of ammonite shells that they do not represent the form of any known creature and therefore could be the remains of extinct species.
His suggestion in Micrographia (1665) that crystal shape can be accounted for by the close packing of spheres.
For all seventeenth century thinkers on geology the time factor was a problem. Hooke was no exception and appreciated that if the world is only a few thousand years old tremendous changes to the earth’s crust must have taken place to account for the observed distribution of rocks. Reluctantly, perhaps, he was the first “catastrophist” and spent considerable time on biblical chronology endeavouring to accommodate his views with religious orthodoxy.
With others he experimented on the nature of the air which he regarded as “the menstruum, or universal dissolvent of all sulphureous bodies” and ingeniously observed that combustion can take place in a vacuum if a constituent of gunpowder; saltpetre or nitre, our potassium nitrate KNO3, is present.
In Micrographia (1665) Hooke displays the porous nature of charcoal and demonstrates that crystal shapes can be produced by the close packing of spheres. Throughout his career Hooke emphasised that the accurate determination of physical quantities such as specific gravity is of importance in accessing the purity of a substance.
Research has shown that Hooke was most hardworking and scrupulously fair in all his dealings.
Hooke was closely associated with Wren’s architectural plans and there is evidence that some churches were largely his work:-
It is now recognised that the Monument to the Fire of London (1677), the 202ft. Doric column surmounted by a dome and copper urn, was largely the work of Hooke and typically the design was such that it could be employed as a zenith telescope.
Hooke’s first independent architectural commission was for the Royal College of Physicians, Warwick Lane and completed in 1679 with a much praised octagonal porch and lecture theatre; a scheme which may have been also employed at the Royal Greenwich Observatory. A delightful commission was received from his former headmaster at Westminster, Dr. Richard Busby, for a church at Willen near the present day Milton Keynes. Other buildings associated with Hooke which can be viewed today are:-
Hooke worked within this tradition and carried the approach forward in the following ways:-
In 1664, working for the Royal Society at Gresham College, Hooke observed the movement of a spot across Jupiter and concluded that the planet has a rotational period.
The publication of Micrographia in 1665 also gave a stimulus to astronomical studies as it included accurate plates on the appearance of the Hipparchus crater. Hooke was aware that the cratering of the moon could be accounted for either as a result of volcanic action or by surface impact, and he carried out experiments on impacting objects into sand..
Hooke made close studies of comets and showed that each had a solid nucleus that emitted its own light. In 1678 he published a lecture on comets establishing their elliptical orbits and speculated that some comets may recur at regular intervals.
Hooke’s last known scientific work was a method for the accurate measurement of the diameter of the sun. This was completed in 1703, the year in which he died.
In 1666 he observed Saturn and made a drawing showing its rings
Hooke and the Royal Society
During the Cromwellian period Oxford became the centre for a group of able young men including Robert Moray, Robert Boyle, John Wilkins, John Wallis, John Evelyn, William Petty and Christopher Wren . Boyle refers to ’The Invisible College or The Philosophical College ‘ in his letters written in 1646 and 1647. Upon the restoration of King Charles II they formed the nucleus of ‘The Royal Society’ which received its first Royal Charter on 15th July 1662. A second Charter was granted on 23rd April 1663, the King was named as Founder, and the name of the Society was changed to ‘The Royal Society of London for the Promoting of Natural Knowledge’ by its second meeting in May 150 members had been elected.
Robert Hooke’s Micrographia
In 1661 Christopher Wren was asked to produce microscopical studies of insects for Charles II. This work was carried forward by Hooke and with the invention of the compound microscope and reached fruition with the publication of Micrographia in 1665. With his startling illustrations like those of the flea and louse, the book was an immediate, widespread and lasting success. In a long but most readable introduction Hooke praises the aims and personnel of the Royal Society and explains that with instrumental advances all the senses could be refined to advance scientific discovery. In such technical work Hooke had an outstanding talent.
A classic of school physics courses, Hooke’s law can be expressed as:-
“When a spring is fixed as one end and a force applied to the other the extension of the spring is proportional to the applied force, provided the elastic limit is not exceeded”
“The deformation of a material is proportional to the force applied”
Hooke illustrated the law by reference to four different experimental situations:-
In Robert Hooke’s time, the science of chemistry was evolving out of the practices of alchemy, metallurgy and pharmacology. Unlike Isaac Newton who devoted a lot of time to alchemy, Hooke was not involved in these topics. Nevertheless, he did important work on the fringes of chemistry.
As an assistant to Robert Boyle (the “Father of Modern Chemistry”) Hooke devised an improved air-pump and important studies were undertaken culminating in Boyle’s law of 1662 relating to the pressure and volume of the air – the “spring of the air” which was investigated with a J-tube apparatus.
Growing up in Freshwater on the Isle of Wight the young Hooke frequently explored an area rich in geological material and from an early age became convinced that some rocks visible on the surface had once been under the sea.
Throughout his career Hooke was fascinated by the subject and regularly lectured to the Royal Society (see Lectures on Earthquakes in Posthumous Works, ed. Waller – 1705). There is a refreshingly modern outlook to Hooke’s thought as is shown by:-
His unflinching belief that fossils are not the result of “seeds” germinating in rock but simply the remains of organic creatures which once existed.
His minute descriptions of fossils and physical explanations for their surface appearance.
Hooke and Astronomy
During the seventeenth century astronomy made tremendous advances and became the focus of interest for professional and amateur natural philosophers alike. Robert Hooke, curator of experiments at the Royal Society, was no exception and actively pursued astronomical work throughout his career. He had a telescope installed in his rooms at Gresham College, and made drawings of his observations many of which he published. He worked to develop and improve the telescope mechanically, and make improvements to the grinding of lenses.
Earlier in the century an active group of north country astronomers –eg. Horrocks, Gascoigne, etc – had made important observations with improved instruments having telescopic sights and eyepiece micrometers. designs of quadrants and sextants for Flamsteed, the Astronomer Royal at Greenwich
Robert Hooke: Surveyor and Architect
Following the Great Fire of September 1665, Christopher Wren was approached by King Charles II to oversee the regeneration of London and shortly afterwards Wren’s friend and fellow scientist Robert Hooke was appointed a surveyor to the city of London. His job entailed: the staking out of streets and foundations; certification of areas taken by the city for new projects; settling of disputes and, reporting on the quality of building, workmanship and cost. In addition he was heavily involved in two major engineering projects, i.e. the conversion of the Fleet River into a canal with wharves, and a new quay on the north bank of the Thames.