Henry Cavendish – Scientific Genius
Peregrine Cavendish, the 12th Duke of Devonshire, is the latest in a long line of Cavendish’s who have served King, Queen and country – and themselves – for half a millennium.
Indeed, this year marks the 500th anniversary of the founding of the Derbyshire dynasty with the birth in 1505 of Sir William Cavendish, the husband of the famous Bess of Hardwick – although the family can trace it’s lineage back across eight centuries to Norman times.
Fifteen generations of Cavendish’s have survived and prospered since Sir William’s son, also William, became the first Earl of Devonshire in 1618, and with more consistent splendour than any other great English dynasty. Down the centuries the family have produced great statesmen – the Fourth Duke of Devonshire was Prime Minister of England, and then Lord Chancellor: proconsuls, great builders and patrons of the arts – and the turf, leading socialites and politicians; several eccentrics, and at least three scientists of note, including one of genius – Henry Cavendish.
Henry Cavendish, eccentric and genius, was born on October 10th, 1731 at Nice in the south of France, where his family were staying at the time of his mother’s confinement. His mother was Lady Anne Grey, daughter of the Duke of Kent and his father was Lord Charles Cavendish, son of the second Duke of Devonshire; thus baby Henry, and two years later his brother Frederick, entered the world with two extremely rich and illustrious uncles – the Dukes of Devonshire & Kent! But sadly, Lady Cavendish died shortly afterwards, Lord Charles never remarried, and the brothers endured a secluded childhood and upbringing at their father’s London house in Great Marlborough Street.
Lord Charles Cavendish was a prominent Whig politician, and also an eminent scientist and mathematician who conducted early experimental work with electricity and meteorology; he was credited with inventing the maximum and minimum thermometer for which he was awarded a gold medal by the Royal Society. Young Henry was often seen in the garden conducting experiments with his father during his schooldays at Dr. Newcombe’s School in Hackney, and he entered Cambridge University in 1749 at the age of eighteen. He left four years later without taking a degree and returned to continue his scientific work alongside his father at Great Marlborough Street, where he remained until Lord Charles’ death in 1783.
It would seem that historically, the aristocracy had a monopoly on eccentricity, perhaps because they alone could afford it; lesser mortals exhibiting such behavioral characteristics ended up either in the workhouse or the lunatic asylum! Henry Cavendish certainly had a peculiarly odd demeanor. He was said to be terrified of women and avoided ever speaking to them, and the female domestic servants had orders to keep out of sight on pain of dismissal, he even ordered his dinner by daily placing a note on the hall table!
Cavendish family biographer, John Pearson describes him as, “a gangling, painfully unsociable bachelor with a high-pitched voice, eking out a meagre income in the absolute obscurity of his father’s house…totally uninterested in any of the things the Cavendishes traditionally believed in – politics, land, wealth or marrying. He was unconcerned with what he wore or what he ate; he was pathologically shy and often at a total loss for words. Yet he was more important than all his Cavendish contemporaries put together, for threadbare Henry Cavendish was a scientific genius, the most original, wide-ranging British man of science since Isaac Newton”?.
He remained an almost total recluse for the remainder of his life, his only social contact being at dinners and meetings of the Royal Society, and he always wore the same crumpled and faded violet velvet frock coat and a three-cornered cocked hat from the previous century. He admitted to “a singular love of solitariness”? and by all accounts exhibited an almost total reticence and a complete naiveté with money. Indeed, Lord Brougham said of him, “Cavendish probably uttered fewer words in the course of his life than any man who lived to four score years”?.
A typical example of his naivety occurred when a Royal Society friend invited him to his son’s christening, and mentioned to him that it was customary to give the nurse a tip on the way out. Henry dipped into his pocket and gave her a handful of gold sovereigns!
Money obviously meant nothing to him and never concerned him, indeed, when first the fourth Duke of Devonshire, and then Henry’s father died, he inherited a substantial fortune and in fact, became the single largest holder of bank stock in England!
Nevertheless, Henry had a great mind, unceasing in its scientific curiosity and enquiry, and in 1766 he published the results of chemical research which fixed his name forever in history as the discoverer of hydrogen, for which he was honoured by the Royal Society.
After his father died in 1783 Henry bought a large house on Clapham Common and turned it into a living laboratory – and he had a back staircase added in order to avoid encountering his housekeeper! His electrical experiments also give an indication of his eccentric methods, for he is known to have measured the strength of electrical current by shocking himself and estimating the magnitude of the pain!
Henry’s only indulgence in luxury was his magnificent library, to which he graciously allowed free access to his friends in the Royal Society. Chambers Encyclopedia of Science mentions this and describes him as, “a silent and solitary man, who had his magnificent library in Soho Square, London – four miles from his residence so that he might not encounter persons coming to consult it”?.
Henry Cavendish’s achievements were prodigious, and he went on to become the first to establish and identify the composition of water, and was the first to establish an accurate composition of the Earth’s atmosphere
He produced the first arsenic acid and discovered the nature of nitric acid, and of the gas which later became known as argon; his research with electricity anticipated the idea of electrical voltage, of positive and negative charges and the accurate measurement of resistance, later known as Ohm’s Law. But such was his reclusive nature that he published very little during his lifetime, and never told the results of his findings to his fellow scientists in the Royal Society. It wasn’t until the late nineteenth century that James Clerk Maxwell, upon examining his papers found that credit to most of his discoveries had already been given to other, later scientists!
Perhaps Henry’s greatest scientific achievement to be credited to him during his lifetime was his accurate calculation of the weight of the Earth. He used a torsion balance to measure the gravitational attraction between lead spheres in 1796-98, from which he calculated Newton’s gravitational constant, G, which he then used to calculate the Earth’s mass.
His results remained the accepted official standard until the twentieth century, and astonishingly the latest measurement which utilizes space-age technology estimates the density of the Earth to be 5.5: over two hundred years ago Henry Cavendish calculated it to be 5.488, a difference of less than 1%.
The older he got, the more eccentric and reclusive he became, refusing to speak to or even acknowledge strangers, and he shunned honours and academic qualifications alike, preferring to hide his own individual light of genius behind the bushel of obscurity. Some commentators have suggested that he may have suffered from Asperger’s Syndrome, whilst others maintain that he was simply naïve and painfully shy.
Pearson writes, “when a distinguished Austrian announced to a gathering at Sir Joseph Bank’s house, that he had come there specially from Vienna in the hope of conversing with Mr Cavendish, `one of the most illustrious philosophers of the age’, Henry fled from the house in horror”?.
Henry Cavendish died in 1810 at the age of seventy nine, and he left a very large estate which was used to endow the world-famous Cavendish Laboratory at Cambridge University in 1871.
Perhaps we should leave the final word about Henry Cavendish, the genius scientist of Clapham to his family: in his `Handbook of Chatsworth’, the sixth Duke of Devonshire, William Spencer George Cavendish (1790-1858) also know as the `Bachelor Duke’, wrote:-
“That philosopher, the man who weighed the world and buried his science and his wealth in solitude and insignificance at Clapham”?.
This article has been brought to you by our resident peak district writerTom Bates