Joseph Priestley (1733-1804), a British scientist, discovered oxygen. He was the first to make and drink soda water, which soft drinks are now made from, and the first to call that stuff that comes from inside trees in South America “rubber” (because he rubbed out pencil marks with it).
He was a friend of Benjamin Franklin and later moved to America where spent the last ten years of his life. There he became friends with Thomas Jefferson.
The Americans claim him as one of their own and France made him a citizen, but he did all his best work while still in Britain.
He favoured both the Americans and the French in overthrowing their kings. This made him hated in Britain, which still believed in kings. His house was burned down once. He was very forgiving about the whole thing, but thought it best to spend his old age in America.
As part of the Lunar Society, which met on the night of the full moon, he knew James Watt and Erasmus Darwin, grandfather of Charles Darwin. He also belonged to the French Academy of Sciences even before he discovered oxygen.
He discovered oxygen in 1775. He was not the first: as he later found out, Scheele in Germany had beat him by a few months. But Priestley gets the credit because he made it public first.
He made oxygen by burning mercury till it turned into a red powder and then heated the powder till it turned back into mercury. The stuff that came out of the red powder into the air made wood burn brighter and made mice move and jump more. He found out the same stuff was coming from plants.
Priestley thought that breathing oxygen would become a fashionable vice among the rich.
Priestley did not call it oxygen, a name we get from Lavoisier. He called it dephlogisticated air because it had no phlogiston.
For over a hundred years science said that things burned because they had phlogiston. Wood is full of phlogiston, so it burns easily. Dephlogisticated air, said Priestley, lacked phlogiston and so took it up readily from things that were burning. This made them burn more strongly.
Priestley did not make a living from science. No one did before the late 1800s when German universities started hiring scientists. Science was just something he did on the side. He worked as a Unitarian minister.
Unitarians are Christians who do not believe in the Holy Trinity. They follow the teachings of Jesus but do not think he is divine. It was the latest thinking in those days and some thought that America would become Unitarian by 1900.
It suited Priestley who thought for himself and was up on all the newest ideas.
Priestley never studied science at university: he studied philosophy and languages. He knew Hebrew and Arabic. It was Benjamin Franklin who later got him interested in science. Franklin was in Britain trying to prevent the coming war between America and Britain.
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