The Invention of Air: A Story of Science, Revolution, and the Birth of America


Thomas Carlyle’s dictum that “the history of the world is but the biography of great men” would be more serviceable, though less aphoristic, if adjusted to: “history is sometimes best recounted through the biographies of great people.” The lives of Benjamin Franklin and Joseph Priestley are perfect cases in point; to describe them is to describe the tumultuous and world-changing second half of the 18th century. This is not just because of the role these men played — Franklin more directly than Priestley — in the American and French revolutions and their aftermath, but because of their involvement in the scientific and intellectual advances of the time, Priestley more directly than Franklin. Because both the politics and the science to which they contributed were elements in the larger story of the Enlightenment, the lives of these men are especially interesting and iconic.

Though Franklin has a significant role in this book, Steven Johnson focuses chiefly on Priestley to draw together the threads of science, politics, religion, and the history and leading personalities of that revolutionary age. He does not offer a biography of Priestley but a sketch of his adult working life and achievements. The book’s somewhat hyperbolic title alludes to Priestley’s discoveries in the chemistry of gases; its even more hyperbolic subtitle alludes to Priestley’s theological innovations, his career as a political pamphleteer, and his friendships with Franklin and — later, when he had been driven into exile in America — Thomas Jefferson.

Without doubt, Priestley’s story is an excellent hook from which to hang the tale of discovery and upheaval that marks the birth of the modern world. Priestley made important discoveries in chemistry, arguably laying the foundations of that science, and in addition made major contributions to contemporary debate in ethics, theology, and politics. His attack on the “corruptions” of Christianity, prompted by his Unitarian outlook and his view of Jesus as a mortal teacher of ethics, together with his support for the revolutionary causes in America and France, put him beyond the pale of conventional “Establishment” opinion in England but earned him extraordinary admiration from other quarters, Jefferson not least among them; indeed Jefferson described Priestley as “one of the few precious lives to mankind.”

Priestley was, in short, a polymath of genius. By the time he left school he knew Greek, Latin, Hebrew, Arabic, French, Italian, German, and the rudiments of geometry and algebra, all but the first two self-taught. At the Dissenting academy in Daventry (none but members of the Church of England could attend Oxford and Cambridge) he learned the basics of science as it then existed, and a lifelong passion for experimental work was born. At first he made a living as a teacher and Dissenting preacher, though his increasingly Unitarian views limited his career in the latter respect. His reputation was soon secured by the success of his researches on electricity and then on air, the first earning him a fellowship of the Royal Society and the second its prestigious Copley Medal.

A remarkable feature of Priestley’s work was its fertility in practical applications. For example: he had to teach himself to draw in order to illustrate his book on electricity, and in the painstaking process of doing so found that India rubber was an excellent remover of lead pencil marks. He commented on the discovery in the book’s preface, and the eraser was born. His work on “fixed air” (carbon dioxide) led to the invention of carbonated water, and soda became a commercial success in his own day. His discovery that plants “dephlogisticate” air was the source of much important chemistry in the work of Priestley’s contemporary Lavoisier (who coined the name “oxygen”) and eventually, two centuries later, led to the concept of the “ecosystem,” recognizing the interdependence of all levels of animal and vegetable life.

Johnson gives an account of Priestley’s scientific work and to a much lesser extent his political and theological writings, adding a commentary on the nature of the growth of ideas and scientific progress as he does so. This part of the book is, alas, repetitive and much padded, and it sometimes reads like a fifth grade textbook. Priestley’s work on electricity and gas is explained in terms too simple to convey either the ingenuity of the experiments performed or their full significance as revealed by later science. Johnson is intrigued by the debates Thomas Kuhn and others have conducted into the way scientific paradigms change, a pertinent matter given that Priestley and his contemporaries were very much engaged in changing scientific paradigms; but this is overdone at the expense of the more interesting story, which is how Priestley’s scientific discoveries were made and what they meant.

The book gets much better in the later chapters, where Johnson describes the hostility Priestley attracted because of his views on the French Revolution. Priestley’s house in Birmingham was burned down by a mob, and he soon afterward went into exile in America, there to become friends with Jefferson and to fall out with John Adams; in the famous correspondence between these two presidents — the correspondence that began long after their respective presidencies were over — Priestly figured centrally, because of a letter Jefferson had sent him immediately on becoming president.

Priestley had nearly been deported under the terms of the highly illiberal Alien and Sedition Acts, which Adams’s administration passed and which Jefferson, though Adams’s vice president at the time, later called “a libel on legislation.” In a way that prefigured General De Gaulle’s refusal to imprison Jean-Paul Sartre (“one does not imprison Voltaire”), Adams refused to have Priestley deported, and when he learned of Jefferson’s critical description of the Acts he wrote to remonstrate, initiating the most stirring phase of the Jefferson-Adams correspondence. All this is well told by Johnson and brings to a fit conclusion the story of Priestley’s remarkable life close to the center of the great affairs of his time.

One thing this short and mainly insubstantial book shows is that a really good biography of Joseph Priestley is long overdue; the last dates to 1931, and given the wealth of incident, importance, science, politics, theology, and great events and individuals involved, the hand of a master is urgently needed to remedy the lack.