There have been explorers who went out into the wild parts of the world and walked there, recording what they found, saw and heard. But another class of explorer remained at home and made a different sort of discovery. One such was Henry Cavendish, who was born on October 10th 1731, at Nice, France (where, by the way, my late wife and I spent our honeymoon). The Cavendish family had a long and illustrious heritage, dating back to the Norman invasion of 1066, and had connections to many of England’s aristocratic families. Henry’s father was Lord Charles Cavendish, who was in turn the youngest son of the 2nd Duke of Devonshire. Henry’s mother, Lady Anne Grey, died in 1733, three months after the birth of her second child, Frederick, and just before Henry’s second birthday.
Young Henry was privately educated before going up to Cambridge University, which he left in 1751, after three years study but without taking a degree (a normal practice at the time). We know very little about his life at this time, but from 1758 he began to accompany his father to the meetings and dinners of the Royal Society of London, to which he was elected a member in 1760. Henry spent his time as a ‘natural philosopher’ as scientists were then called, being by turns a mathematician, electrician, astronomer, meteorologist, geologist, and chemist; he published his first paper On Factitious Airs in 1766.
|Henry Cavendish - On Factitious Airs|
Over the next forty years, he continued his experimentations but published little (nineteen papers in the Philosophical Transactions of the Royal Society, on a wide variety of subjects), and it seems that for Cavendish the work itself was sufficient reward. He left a vast amount of unpublished papers behind after his death, many of which were consequently edited and published by the physicist James Clerk Maxwell, and which were found to have either discovered or anticipated many phenomena or discoveries attributed to later scientists. Much of Cavendish’s work is written using old-fashioned words and terms which, although quaint, are nonetheless accurate.
|Page from Cavendish's notebook|
He discovered that water was not an element, as taught by the ancients, but was a compound of two gases, which we call hydrogen and oxygen, but which Cavendish called ‘inflammable’ and ‘dephlogisticated’ airs – this same discovery also nullified the concept of fire as an element. By dissolving metals in acid, Cavendish isolated his ‘inflammable air’, later named hydrogen by Lavoisier under his great ‘chemical revolution’. He also made extremely accurate measurements of the proportion of the gases constituting atmospheric air.
|Dedication to Henry Cavendish|
Cavendish’s reticence to publish may be related to his reticence to interact socially. He was an extremely private man, to a point that puts him firmly in the autistic spectrum (Oliver Sachs, the neurologist, speculates that he may have suffered from Asperger’s Syndrome, an opinion with which I agree). When attending the soirees of Sir Joseph Banks, Cavendish would stand transfixed on the stairs until another visitor arrived behind him, forcing him to flee forwards and into the party. At one meeting, Dr Ingenhousz introduced Cavendish to a visiting Austrian scientist, the pair of them describing poor Cavendish in florid, extravagant language, as he stood in misery, staring at the floor. Spotting a gap in the crowd, Cavendish bolted for the door and ran to his carriage, which carried him home and to safety at high speed.
Dr Wollaston's suggested the following method of conversation,
“The way to talk to Cavendish is never to look at him, but to talk as if it were into vacancy, and then it is not unlikely you may set him going.”
When he did reply, which was not often, he mumbled and muttered in a high-pitched squeak, but what he did say was always profound and relevant. His town-house, near the British Museum, was furnished with books and scientific equipment, although he also enjoyed fine, elegant furniture, but hated visitors. In a bid to discourage them, he kept the body of his books at another house in Soho, where he employed a librarian, and would go and ‘borrow’ his own books as and when he needed a particular volume, leaving a receipt for it. He also had a villa at Clapham, the upper-rooms of which were an observatory, the drawing room was a laboratory and in an ante-room was a forge. His heir, Lord George Cavendish, was allowed to visit, once a year, for a maximum of half an hour.
|Machine for testing Leyden vials|
His scientific apparatus was built for purpose, not for beauty, quite often from cheap pine, rather than the ornate contraptions of brass and mahogany of other gentlemen scientists. The fashion of his dress never altered, being shabby and old-fashioned, leading many of the villagers to assume he was a ‘magician’, and, of course, he would not sit for a portrait, although we have one quick sketch, surreptitiously drawn by Mr Alexander at a Royal Society dinner.
|Alexander - Portrait of Henry Cavendish|
It was said that he had a second, hidden staircase installed at the Clapham villa, to allow the servants to move about the house unseen, and if he ever caught sight of a housemaid, she would be instantly dismissed. He communicated with his housekeeper by means of notes, which were left on the hall table. Two ladies had told a inquisitive gentleman of the path Cavendish took on his daily walks and they set out to observe him, but their target, who saw them as he was climbing a stile never used that route ever again.
|G Wilson - The Life of the Hon. Henry Cavendish|
Up until the age of forty, Cavendish had an income of about £500 per year, but then his uncle died and left him an enormous fortune, which was further increased on the death of his father, but as with most quotidian matters, Cavendish was utterly indifferent to money. His bankers, concerned at the amount resting in his account, sent a messenger to Clapham to seek an audience with Cavendish, who demanded to know why he was being disturbed in this fashion. The messenger told him that he had £80,000 in his account, doing nothing, and suggested he might invest £40,000 of it. The reply was simply, “Do so, do so! And don't come here to trouble me, or I'll remove it.” When he died, in 1810, he left the highest bank-stock on record in the Bank of England, in excess of £1,157,000, (remember, a domestic servant would have earned about £10 per year at the time). His death was as odd as his life, and was related by Mr H Lawson, an acquaintance of Cavendish’s, thus,
“He went home one evening (I believe from the Royal Society) and passed silently as usual to his study. His man-servant observed blood upon his linen, but dared not ask the cause. He remained ill for two or three days, and on the last day of his life, he rang his bell somewhat earlier than usual, and when his valet appeared, called him to the bedside, and said, “Mind what I say —I am going to die. When I am dead, but not till then, go to Lord George Cavendish, and tell him of the event.”
Half an hour later, he re-called the valet and asked him to repeat the previous instructions and when satisfied, asked for a glass of water. He took a sip, turned onto one side and died, silently and peacefully.
Happy Birthday Henry.