Henry Cavendish (1731 – 1810) died decades before William Whewell (1794 – 1866) coined the term “scientist” to describe those who investigated and classified the physical world, and was known in his time by the term natural philosopher instead. He was also known for being immensely wealthy, well-connected and rather eccentric. Even more importantly, Cavendish was a highly esteemed experimenter in atmospherics, magnetism and electricity, and the man who determined the mass of the Earth.
There is a black plaque to Henry Cavendish at 11 Bedford Square WC1, which is the north-east corner where Montague Place begins. It is difficult for the casual passer-by to notice, as it blends in rather well with its dark brick background. In this house, purchased around May 1783, Cavendish created a museum, a laboratory, and a scientific lending library of roughly 12,000 volumes contained in row upon rowsof elaborate sliding shelving, available to colleagues and other gentlemen who had been properly vouched for:
“The colour scheme of the furnishings was consistent: green moreen window curtains, green transparent-lined mahogany blinds, green chair covers, and fire screens covered in green silk. The furniture was mahogany. By far the greatest part of the house was given over to books and such fixtures as book users require. The house may also have been used to display Cavendish’s mineral collection. With the exception of the dining and back parlor room, all of the main rooms had bookshelves. So altered was the house that, according to an estimate after Cavendish’s death, a sum equal to a quarter of the value of the house would have been required to restore it to a condition ‘fit for the residence of a family’.” (Cavendish, Christa Jungnickel & Russell McCormmach 1996, p. 233).
“…his books were at the command of all men of letters, either personally known to him, or recommended by his friends: indeed the whole arrangement was so impartially methodical, that he never took down a book for his own use, without entering it into the loan book; and after the death of a German gentleman, who had been his librarian, he appointed a day on which he attended in person every week for the accommodation of the few, who thought themselves justified in applying to him for such books as they wished to consult. (The Scientific Papers of the Honourable Henry Cavendish, Henry Cavendish & James Clark Maxwell 2011, p. 445).
Oh, to have been a fly on the wall in Cavendish’s library…
“While travelling in England, in 1790, with Georg Forster [1754 - 1794], [Alexander von] Humboldt [1769 - 1859] obtained permission to make use of the library of the eminent chemist and philosopher, Henry Cavendish … on condition, however, that he was on no account to presume so far as to speak to or even greet the shy and aristocratic owner, should he happen to encounter him. Humboldt states this in a letter … adding, sarcastically, ‘Cavendish little suspected, at that time, that it was I who, in 1810, was to be his successor at the Academy of Sciences.’” (British History Online)
Biographer George Wilson and other sources refer to another of Cavendish’s lending libraries being housed at his home in Dean Street, Soho. In all likelihood, he kept extensive book collections in many locations.
Wilson describes Cavendish as a kind of genius scientific all-rounder:
“He was an excellent mathematician, electrician, astronomer, meteorologist, and geologist, and a chemist equally learned and original. In the fullest sense of the term, indeed, he was a natural philosopher, and had he published during his lifetime all the researches which he completed, his reputation would have been much wider and more varied even than it was.” (The Life of the Honourable Henry Cavendish, George Wilson 1851, p. 19).
His shyness and eccentricity were often remarked upon, and Cavendish was regularly observed fleeing interactions with women and strangers, and hovering on Joseph Banks’s (1743 – 1820) doorstep, summoning the courage to enter the latter’s regular intellectual soirées. One tactic his colleagues employed when they wanted to converse with him was to look in the other direction and address the empty space, at which point Cavendish, out of the spotlight, might feel brave enough to make a reply. His contemporary, Sir Humphry Davy (1778 – 1829), described Cavendish thus:
“Cavendish was a great man, with extraordinary singularities. His voice was squeaking, his manner nervous, he was afraid of strangers, and seemed, when embarrassed, even to articulate with difficulty. He wore the costume of our grandfathers; was enormously rich but made no use of his wealth. He gave me once some bits of platinum, for my experiments, and came to see my results on the decomposition of the alkalis, and seemed to take an interest in them; but he encouraged no intimacy with anyone … He lived latterly the life of a solitary, came to the club dinner, and to the Royal Society, but received nobody at his own house. He was acute, sagacious, and profound, and, I think, the most accomplished British philosopher of his time.” (Wilson, p. 167).
Now to Cavendish’s scientific endeavours, which are so numerous that I will mention only a few, paraphrasing Simon Schaffer - who summarised Cavendish’s achievements for the Oxford Dictionary of National Biography.
Henry Cavendish was remarkably talented at devising experiments and fine-tuning instruments, in order to quantify a variety of phenomena in physics and chemistry – although notably, not biology. He was an “expert chemical analyst … [who] created a gravimetric scale of phlogistication … [and] a global theory of heat, chemistry, and rational mechanics.”
The Royal Society awarded Cavendish the Copely Medal in 1766, for his papers on the chemistry of ’airs’ and waters – he demonstrated that “there was a range of chemical airs or gases of different specific gravities.” He played the role of advisor and auditor for the 1769 transit of Venus observations conducted by Captain Cook (1728 – 1779) and crew in Tahiti, and advised Cook on the use of magnetic needles for his third voyage.
As for measuring the Earth’s density, Cavendish’s experiment “involved measuring the gravitational torque on a 6ft wooden rod carrying two small lead balls acting under the pull of two large weights nearby. The apparatus was isolated and its motions observed during more than two hours through a telescope focused on a vernier scale. Cavendish concluded that the earth’s density was just under 5.5 times that of water. The results were published in 1798, and helped reinforce Cavendish’s reputation for conscientious precision.”
Henry Cavendish’s other London residences included:
13 Great Marlborough Street W1F
Just south of Oxford Street, he lived here with his father for many years. The house (now demolished) served as a scientific laboratory as much as a place of abode – all manner of experiments were conducted here above the stables and in the back garden, including meteorological and magnetic observations, and experiments with gases and liquids. Decades later, the building was home to experiments of a very different kind – a later occupant was anatomist Joshua Brookes (1761 – 1833), who:
“…had a ‘Theatre of Anatomy’, here during the period 1786–98, where he gave lectures and exhibited the bodies of notorious criminals. [In the garden] Brookes had a vivarium, ‘constructed principally with large masses of the Rock of Gibraltar’, where he kept chained wild animals. An eye-witness of the fire which destroyed the Pantheon in January 1792 related how the mob, looking through the iron gates to Brookes’s garden and seeing the discomfiture of the animals from the heat of the fire, threatened ‘to pull the house about his ears’. (British History Online).
34 Church Row, Hampstead NW3
Cavendish moved here after his father died, although he held onto the Great Marlborough Street house. In Hampstead, among other things he:
“determined the error of the time given by the meridian line by comparing the times of rocket explosions observed at Hampstead with those of Greenwich and at Loam Pit Hill … Hampstead parish church at the end of Church Row … served Cavendish as the prominent, nearby object for determining the bearings of his new location … He sighted on the church’s weathercock, and from the steeple, he or an associate took angles with a quadrant of conspicuous objects … So commanding was the view … that Cavendish was able to take in much of London and its outlying villages with his instrument. He could look down on the properties of his family, the Duke of Devonshire’s Palladian house at Chiswick … and even on the steeple of the church at Clapham Common … where Cavendish would soon own his next country house.“ (Jungnickel & McCormmach, pp. 230 – 231).
Dean Street, Soho W1D
Several sources mention that Cavendish operated another lending library at this location.
Cavendish Road, Clapham Common SW4
Specifically, the end of Cavendish Road (also called Cavendish Parade) which meets the south side of Clapham Common. He moved here, to his favourite among all his residences, in about September 1785. The house, also decorated in green, no longer exists and is now replaced by a row of shops.
“This house was set apart not by grandeur but by the towering ship’s mast in the back, a mount for aerial telescopes, and upon closer inspection, by the thermometers and other instruments stuck all around it, and inside by its laboratory for a drawing room, forge for an adjacent room, and observatory for another room. Cavendish’s premises gave the largely correct impression that he made little distinction between his personal affairs and natural philosophy.” (Speculative Truth: Henry Cavendish, Natural Philosophy, and the Rise of Modern Theoretical Science, Russell McCormmach 2004, pp. 97 – 98).
“It was stuck about with thermometers, rain gauges, etc. A registering thermometer of Cavendish’s own construction, served as a sort of landmark to his house … A small portion only of the villa was set apart for personal comfort … The lawn was invaded by a wooden stage, from which access could be had to a large tree, to the top of which Cavendish, in the course of his astronomical, meteorological, electrical, or other researches occasionally ascended.” (Wilson, p. 164).
His favourite walk in Clapham, which Cavendish performed like clockwork, went down Nightingale Lane ( stone’s throw from his house) past Clapham Common, along to Wandsworth Common and back again – and he took care to walk in the middle of the road, perhaps to avoid interaction with other pedestrians.
Photos by Sven Klinge
(please credit photographer & website when using these photos)
- The Life of the Honourable Henry Cavendish by George Wilson
- Speculative Truth: Henry Cavendish, Natural Philosophy, and the Rise of Modern Theoretical Science by Russell McCormmach
- Electrical Researches of Henry Cavendish by Henry Cavendish & James Clark Maxwell
- The Scientific Papers of the Honourable Henry Cavendish by Henry Cavendish & James Clark Maxwell
- Cavendish by Christa Jungnickel & Russell McCormmach