Today is the birthday of Henry Cavendish, who was born in Nice in 1731. Henry was a natural philosopher, which is what scientists were known as in the eighteenth century. He came from and extremely wealthy family, was a member of the Royal Society and was also painfully shy. He was so shy that this drawing is the only image we have of him that was drawn from life. The man who made it had to sketch it in secret from the other side of the room. The coat and hat he is wearing were very old-fashioned, but it wasn’t the type of thing that bothered him. When his coat wore out, he would have a new one made exactly the same.
Although he attended Cambridge university for three years, he left without taking a degree. The idea of sitting in front of an examiner was just too much for him. Instead he returned to his father’s London home where he set up his own laboratory. I don’t really know what he did for the next seven years, because he like to keep himself to himself, but in 1758 he started to go to the Royal Society with his father. In 1760 he was made a member. Dinners at the Royal Society were pretty much his only social appointment. At home, he found ordering dinner difficult. Although he was generally easily flustered by human contact, he was particularly alarmed by women. So any contact made with his female servants was done via a note left on the hall table.
Despite his oddities, he was a very gifted experimental scientist, a fastidious observer and note taker. A lot of the discoveries he made went unrecognised until long after his death because he published very little. He was the first person to investigate the properties of hydrogen, which he made by dissolving metals in strong acid. He named it inflammable air, for obvious reasons. He also experimented with igniting his flammable air in oxygen, which was then called ‘phlogisticated air’ and found that it produced a small amount of water. Without really understanding the principals, he had found out that water was made from hydrogen and oxygen.
His other famous experiment was the time he worked out the weight of the earth. He was trying to find out it’s density and to do this he needed to measure the gravitational pull of much smaller objects. The way he did this is terribly complicated and, not being a scientist, I find it difficult to understand, let alone explain. It involved some lead balls suspended inside a shed. Cavendish had to observe his experiment from outside the shed using a telescope to avoid either the mass of his own body or air currents disturbing the results. His experiment was so precise, that the answer he came up with was within one percent of the current accepted figure. For decades after his death, parents enjoyed pointing out Cavendish’s shed to their children and telling them that it was ‘the shed where the earth was weighed’.
Henry Cavendish was very highly respected by his contemporaries at the Royal Society, but if they wanted to hear his thoughts on a particular subject, it was rather difficult. Their best bet was to stand somewhere near him and wonder aloud, addressing the room in general. If they were lucky, he might mumble a reply. If they weren’t, they might just hear a squeak and catch sight of him as he ran away. Cavendish had a large library which he moved from his house to a separate building so that he wouldn’t be worried by people who wanted to borrow his books. He employed a librarian and if he wanted to look at one of his own books, he would go along to his library and fill out a slip just like everyone else.
His inability to socialise and his high degree of precision in his experiments have led people to speculate that he may have suffered from Asperger syndrome. He really seems to have been an archetypal science nerd.. Imagine Raj Koothrappali from the Big Bang Theory, but in Georgian Britain.