24th March: Joseph Priestley

This date in 1733 saw the birth of Joseph Priestley, English clergyman and scientist who discovered Oxygen, sulphur dioxide, silicon fluoride and ammonia. Here are ten facts about him you may not be aware of:

1. He never took a formal science course in his entire life. He was primarily a clergyman (classic case of nominative determinism here - a clergyman called Priestley!) with an interest in science.
2. At the age of four he could recite all 107 questions and answers of the Westminster Shorter Catechism, leading his aunt, with whom he lived, to pursue the best education for him with a view to him entering the ministry.
3. When he was about 17, he became seriously ill and thought he was going to die. The illness shook up his religious beliefs and left him with a stutter, which delayed his entry to the ministry for a while.
4. His first position as a minister was in Needham Market, Suffolk. It didn't work out well. He missed urban life and theological debate. His congregation were traditional in their beliefs and many stopped attending his church when they found out how progressive he was. He moved to Cheshire which turned out to be a much more suitable placement.
5. His interest in science was nurtured by his friendship with Benjamin Franklin (the one who flew Kites in thunderstorms). Priestley began reproducing some of Franklin's experiments which led to his discovery that graphite conducts Electricity. Priestley went on to write a book about electricity - The History of Electricity, which was well received by the scientific community.
6. When he moved to a position as a pastor in Leeds, he lived next door to a brewery and became intrigued by the gas (which he called "air") which was given off by the fermenting grain, would float to the ground and extinguish smouldering wood chips. This was carbon dioxide. He was so interested in it that he found a way to make it at home. One of the things he tried doing with it was dissolving it in Water. He found it made the water taste tangy. He'd just invented soda water. This got him elected to the French Academy of Sciences.
7. Priestley was considered for the position of astronomer on James Cook's second voyage to the South Seas, but wasn't chosen. However, he told the crew how to make soda water, which he believed might be a cure for scurvy.
8. He found a way to collect gases by floating them on Mercury and heating them. One of the gases he found in this way was oxygen, which interested him because, unlike the other gases he'd found, he could burn candles in it and Mice put in the chamber didn't die. He was also the first to observe photosynthesis in plants.
9. Priestley was also the person who first discovered that India gum could be used to rub out lead Pencil marks. He invented the eraser, or rubber.
10. Priestley persisted in some antiquated beliefs about science, however. Even though he discovered oxygen, he rejected the idea that it was oxygen that made things burn. He believed in a theory called phlogiston theory, that there was an element present in combustible materials that was released as they burned. He refused to accept the new theories scientists were coming up with, which we accept as correct today. The 19th-century French naturalist George Cuvier said of him that he was "the father of modern chemistry [who] never acknowledged his daughter".