A priest, a linguist, and a chemist walk into a bar. Some might mistakenly think this is the start of a bad joke. Instead it's just the life of citizen scientist Joseph Priestley.
Most people learn about Priestley as the man who discovered both carbon dioxide and oxygen. They may also learn about his role as the first person to describe photosynthesis. But what they likely don't learn is that he was just an amateur scientist with no academic training in the sciences. It wasn't even his initial occupation (clergyman) or what he is most known for (philosophy). To help round out this fascinating man, Author John Malone gives a short yet insightful description of his citizen science background in his book "It Doesn't Take a Rocket Scientist: Great Amateurs of Science".
Born on March 24, 1733, Priestley spent his early years raised as a Calvinist but quickly began searching for his religious bearings, ultimately becoming a priest in the Dissenter (and later Unitarian) church in his late teens. He spent this time preaching at local churches, writing well-regarded books on grammar, and teaching both languages and rhetoric.
While his newfound faith may have separated him from the mainstream of religious thought of that era, it did open up a world for new philosophical inquiry. This would come into play when a met a famous American in his mid 40s. As Malone describes it,
"Unitarians tended toward very liberal political views from the starts, so it was hardly surprising that Priestley would hit it off so well with Benjamin Franklin when the two met in London in 1776….The interest in electricity that Franklin aroused in Priestley was strikingly rewarded within a year, when the clergyman was able to demonstrate that graphite conducted electricity."
How did this meeting happen? Well, by the 1770s Priestley had already been making quite a name for himself. As a "quintessential amateur" he had a curious mind that would latch onto a question, research it, and methodically experiment until he found his answer. This led to one of his earliest discoveries, the creation of sparkling water by infusing carbon dioxide into water, and earned him the prized Copley Medal in 1773.
With the Copley in hand he quickly earned a spot in the Royal Society in 1776. It also helped him land the rich William Petty (Earl of Shelburne) as a patron for his future studies. As Malone again describes,
"It was quite common among the aristocracy to employ an artist, writer, or naturalist (as scientists were generally called) to serve as an intellectual companion. By this time Priestley was quite a catch, and he was able to command a very comfortable situation…It was over the next several years that Priestley did his most important scientific work."
Having a patron meant not just a steady source of income, but also a steady source of time for devoting to one's personal interests. This let Priestley continue letting his mind wander. For example, at one point he had heard of some discoveries from the mysterious Americas that were all the rage in Europe. There was one tree in particular with a "a gummy substance secreted by a South American tree" that had very unusual properties. Many people were playing and experimenting with it. But Priestley was the first person to notice that not only was it stretchable and pliable, but it could also be rubbed on a piece of paper to make any writing on it disappear. He called this a "rubber" and the term, as well as his invention of the eraser, stuck.
While having a patron probably ended his time as a "citizen scientist", many of his discoveries came before he had this support. He just kept up with the discoveries of the day and was an avid experimenter, often using items from around the house (such as laundry tubs or household jars) for his research. While he would later have friends like china-maker Josiah Wedgwood create custom laboratory equipment for him, he still discovered much as an amateur with materials from home.
It should be noted one of the other reasons Priestley became so famous. Not only was he naturally curious and an astute scientist, but he also knew the value of quickly publishing his discoveries. Unlike some modern amateur scientists who may be intimidated by the committing themselves formally to paper, Priestley recognized it's value. In fact his early publication helped support his claim as the first to discover Oxygen, when two others (including Antoine Lavoisier) later tried to take credit for it.
Ultimately Joseph Priestley died in early 1804 after a distinguished career. In his book Malone sums him up best:
"Most great amateur scientists are known to us chiefly because of that scientific work. But Priestley was different.. His theological treatises had great impact, particularly in America, where the first Universalist church to carry that name was founded in Gloucester, Massachusetts, in 1799. Some treatments of Priestley's life are chiefly devoted to his theology and the liberal political beliefs associated with it. Others concentrate on his numerous scientific discoveries. Some religious historians claim that Priestley would have wanted to be remembered primarily as a theologian, but others are quite certain that his discovery of Oxygen was the high point of his life...He was certainly a very influential theologian, but he was also a major scientific figure. In fact, Joseph Priestley packed more accomplishments in to a lifetime than most of us can even dream about, to the extent that it is difficult to see him whole, so brightly do the individual parts shine."