The Invention of Air

What’s the fun in writing about someone everyone already knows about? I think there’s something exciting about taking historical figures who should be better know, and telling their story in a way that hopefully shows their importance to modern readers. That’s exactly what I tried to do with John Snow in The Ghost Map – take a relatively obscure event and make the case for why it was one of the turning points in modern civilization. There’s a comparable argument here with Priestley: not only was he a brilliant and influential scientist and intellectual, but he’s a missing link between some of the most famous names in American history, a kind of “lost” founding father.

What connection did he have to America’s Founders? How did he get to know Franklin, Adams, and Jefferson intimately?

Priestley got to know Franklin first, because of course Franklin lived in London for many years of his life. (In fact, had the conflict that led to the Revolutionary War not broken out, it’s entirely likely that Franklin would have remained in London for the rest of his life.) They were both part of an informal club of scientists and political thinkers – Franklin dubbed it the “Club of Honest Whigs” – that met that the London Coffeehouse once every two weeks. He met Adams during the 1780s when he was Ambassador to England, and they had a somewhat volatile relationship the next decade after Priestley emigrated to America. Priestley didn’t meet Jefferson until he moved to America, but the two men had a wonderful correspondence in the final years of Priestley’s life.

How did he come to have such a major influence on them?  What values and beliefs did he share with them?

One of the reasons that I think this story is so important to us today is that it sheds a new light on the values of the Founders when you recognize the importance of Priestley in their story. (Priestley is mentioned more than ten times as frequently as Washington or Hamilton in the famous Adams-Jefferson letters, after their reconciliation in 1812, which gives you some sense of his centrality.) One key value that they shared was an abiding belief in science and the enlightened progress that science had brought to the world. (Priestley called it “natural philosophy” in the language of the period.) The other was the recognition that this enlightenment would force us to reinvent all our old conventions and beliefs about religion, society, and politics. The idea of political figure adopting a know-nothing attitude towards the innovations of science would have been appalling to the Founders.

What were his major scientific discoveries?  Was he really the first person to discover oxygen?

Priestley is most famous for discovering oxygen, but one of the interesting twists in the story of his life is that he didn’t really discover oxygen first, and some of his analysis of what he had discovered turned out to be fundamentally flawed. Part of the argument of the book is that Priestley should be remembered more for another discovery of his, which in its own way was every bit as important: He was the first person to recognize that plants were creating oxygen. The original oxygen content of the earth’s atmosphere was vanishingly small; the whole reason we have an atmosphere that we can breathe is because the plants manufacture oxygen for us. And Priestley was the first person to grasp that essential life-support system. (Interestingly, Franklin helped him understand the full implications of his discovery, so in a way, it was a collaboration between the two men.)

How is Priestley related to today’s ecosystem science?

The discovery of plant respiration is now seen as one of the founding insights that ecosystem science is based on, but Priestley also played a key role in teasing out the energy flows of photosynthesis, and published an influential paper on the way animals use oxygen as an energy source via the bloodstream. Priestley helped sketch out the first draft of the cycle of life on Earth: plants convert the energy of light into chemical energy, releasing oxygen into the atmosphere and absorbing carbon dioxide; animals power themselves through the energy stored in plant tissue and oxygen itself, releasing carbon dioxide as a waste product.

How was he supported in his endeavors?  And how was that support linked in a hidden way to the scientific discoveries he was making?

At various points in his life, Priestley drew a salary as a minister and a teacher, but he was also supported by a series of patrons, most notably Lord Shelburne, on whose estate he worked for most of the 1770s, and then the extended group of the Lunar Society in Birmingham, a band of pioneering industrialists who endowed Priestley with enough money in the 1780s to support his research and writing. The Birmingham magnates had themselves built their wealth by exploiting the stored energy of the coal deposits in the British Midlands; that coal was originally laid down during the massive spike in oxygen levels that occurred in the Carboniferous Era, thanks to the very process of plant respiration that Priestley had discovered.

How were Priestley’s scientific discoveries tied to his religious writings and his political beliefs?  Why was it so natural for him to move freely among science, religion, and politics and to make connections among them?

Simply put, the modern specialization and professionalization of knowledge – one of the defining developments of the 19th-century – simply hadn’t happened yet. One of the things that I find so moving and intriguing about Priestley is that he was, in a sense, part of a dying breed: the amateur, the dabbler, the polymath who had his fingers in a dozen different fields. It’s much harder to pull that sort of thing off today, in part because the fields have grown so much more complex, and in part because we have institutions that have solidified around each distinct field, prohibiting the kind of cross-breeding that Priestley and his peers reveled in. 

What enabled Priestley to take part in so many intellectual revolutions simultaneously?  His personal qualities?  The nature of his times?  Luck?

That’s one of the great questions that I try to wrestle with in the book: why this particular guy at that point in time? Because as interesting as the story is, I think it’s just as important to try to figure out why the story happened the way it did. And the answer is that there were multiple, interacting causes that made Priestley’s ideas so revolutionary and influential. Some of them had to do with his temperament and his methodology (he was a brilliant improviser – a hacker of sorts, in the modern idiom –  but not a theorizer); some of them had to do with the information networks that he participated in, with the Honest Whigs and the Lunar Society; some of it had to do with accidents of history and personal biography; for instance, he got interested in air in part because he happened to move into a house that was next door to a brewery, which ultimately led to what he called his “happiest discovery”: he invented soda water.

What do you mean by the Long Zoom approach to history?

This is a theme that runs through all of my books, and was central to the approach of Ghost Map as well. The idea is that you can’t properly answer the question of why things happen – why big ideas emerge and change the world, for instance – purely on the level of “Great Man” or “Social” historical accounts. The biographical details of an individual’s life are important, of course, as are social movements, but there are many other levels that need to be explored, each of them existing on different scales of experience. One key theme of Invention of Air is the changing flows of energy through natural and human systems, but I also talk about the impact of coffeehouses on Enlightenment science. That’s the long zoom, the conceptual movement from the very large to the very small, that tries to build explanatory bridges between each level.

Why was Priestley driven out of England by violent mobs?

What kind of reception did he receive in America?

What role did Priestley play in the bitter personal and political feud between Adams and Jefferson, and in their ultimate reconciliation?

This is one of the narrative threads in the book that I most enjoyed piecing together, because it’s a story of three men and their shifting relationships that simultaneously plays out on a much larger scale. Priestley ultimately allied himself with Jefferson’s emerging Republican party during the Adams administration, and nearly got himself arrested under the notorious Alien and Sedition acts. (Priestley’s neighbor and collaborator was one of the few people who actually served time under the controversial laws.) Shortly after he was sworn into office in 1803, Jefferson wrote to Priestley to apologize for the shameful (and unconstitutional) treatment he had suffered at the hands of the Adams administration. Ten years later, well after Priestley’s death, a copy of that private letter between Priestley and Jefferson fell into Adams’ hands. Adams, of course, was notoriously thin-skinned, and he erupted at the betrayal and the contempt that he read in Jefferson’s words. The debate that follows is really the core turning point in the Jefferson-Adams correspondence, and we have Joseph Priestley to thank for it.

What have we lost by separating science and politics into largely separate spheres today?

I start the book with a quote from a presidential debate from 2007, where a leading candidate – I won’t mention his name – was asked whether he believed in the theory of evolution. “It’s interesting that that question would even be asked of someone running for president,” he responded. “I’m not planning on writing the curriculum for an 8th grade science book. I’m asking for the opportunity to be president of the United States.” To be so willingly, so openly removed from the insights of science would have appalled Priestley and the Founding Fathers. (In part the whole dispute between Adams and Jefferson erupted because Jefferson called Adams anti-science in his letters to Priestley.) And it would have appalled them for good reason, because we live in age where both everyday experience and global politics are hugely effected by the path of scientific innovation and understanding: think global warming, stem cell research, genomics, computer science, and so on. To happily profess your ignorance of that world while simultaneously asking to be elected to public office is clearly irresponsible. But it’s also something more than that, given the story that I tell in this book. It’s downright un-American.