Joseph Priestly is best known for discovering oxygen, but Steven Johnson, author of a new biography of Priestly titled The Invention of Air, points out that his contributions were much larger: he was the first ecosystems thinker, almost 200 years ahead of his time. Priestly was best friends with Benjamin Franklin, he wrote about major scientific discoveries in popular literature, and was highly revered by George Washington, Thomas Jefferson and John Adams.
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Johnson’s previous books have covered everything from the impact of popular culture on neuroscience and the19th-century cholera epidemic in London. Smithsonian’s Bruce Hathaway spoke with Johnson about his discoveries in The Invention of Air.
People who recognize the name Joseph Priestly think of him as the discoverer of oxygen. But you say that emphasis completely misses his most important contributions, one of which was the discovery of how plants sustain other life on earth.
The work with oxygen is the one thing I knew about him. And it’s the first line in his biographies everywhere you look. But it’s not entirely true. He wasn’t really the first. Carl Sheele was probably the first. And Priestly was messed up in his understanding of oxygen. Ultimately it was Antoine Lavoisier, in part building on Priestly’s thinking, who got it right about oxygen. It’s possible that if Priestly had not been so much of a polymath that he would have fully understood oxygen. But Priestly was not a systematic thinker. He was a great experimentalist and was incredibly clever at devising these experiments and coming up novel data for people to wrestle with. But he was never particularly gifted at taking the crazy things that he would discover and turning them into a systematic theory of the world. He was interested in finding these weird puzzles and letting other people solve them.
I think one of the things we have to recognize is that there are two kinds of minds in revolutionary science, science that changes the world. There are people who are really good at exploding the existing paradigm and then there are people who once the old paradigms are exploded are good at sorting. Priestly was the former, not the latter. Science needs both kinds of minds.
And you say that Priestly’s great discovery [of oxygen?] was quite a coincidence?
There were a bunch of interesting accidents in Priestly scientific life. One of the big ones was that he once moved randomly next to a brewery. He was ever inquisitive, so he went over to check out what they were doing. He noticed that there were interesting gases coming up from the big vats of beer they were brewing so he asked these guys if he could do some science experiments. What an incredible image. A weird scientist wanting to do experiments over beer.
And due to that fiddling, Priestly invented soda water?
Yes. Just by pouring water back and forth over these vats he noticed that it had a delightful fizzy flavor. So he got interested in gas in part because of this. Priestly’s brother said that when Joseph was like an 11 year old he trapped spiders and mice in little jars and waited to see how long it would take for them to die. So Priestly had long known that if you take a closed, sealed vessel and put an animal in there after a certain amount of time they’re going to use up all the air and they’ll die. But it wasn’t understood why that was happening and what was happening. Were they adding something to the air that was poisoning it? Were they taking something from the air? No one knew just what was happening.
Joseph Priestly suffocating mice and spiders just sounds sadistic. How did any scientific good come out of that?