To do justice to such broad intellectual engagement requires equally broad scholarship, and in Robert Schofield, Joseph Priestley has met his match. The book under review here is the much-awaited second volume of the definitive intellectual biography prepared by this Iowa State University emeritus professor. The first volume (1), published in 1997, received glowing reviews by William Jensen in this Journal (2) and by this reviewer in Perspectives in Physics (3). The Enlightenment of Joseph Priestley began with the subject’s birth in Yorkshire and concluded in 1733, when he was about to become librarian–companion to Lord Shelburne. It was in this capacity and his subsequent residence in Birmingham that the Unitarian cleric did his most important research in pneumatic chemistry. Therefore, the second volume devotes more space to Priestley’s scientific work than does the first, but still only five out of 17 chapters. If anything, this ratio may overemphasize the science.

In the preface to this volume, the author describes his work as “a biography intended for historians of science, chemists, and theologians, as well as intellectual and cultural historians”. Schofield writes, “I have consulted and described every published writing of Joseph Priestley and attempted to place every bit of it in its historical context.” This is no mean task: the standard collected (but incomplete) non-scientific works fill 26 volumes.

The book is chronologically divided into three parts corresponding to the places where Priestley lived: Part I: Calne (1773–1780), Part II: Birmingham (1780–1791), and Part III: Clapton/Hackney (1791–1794) and Northumberland (1794–1804). Each part is subdivided into chapters that focus on certain aspects of Priestley’s life and work during the period in question, for example “Religion and Theology”, “Matter and Spirit”, “Science and the Chemical Revolution”, and “Emigration to the United States, Politics, and Education”. A typical chapter is organized around the relevant works published by Priestley, and Schofield provides summaries of the background, content, argument, and reception of these writings. Understandably, these précis cannot be complete, but they offer interesting introductions to readers who might wish to seek out the originals. Moreover, there are copious references to secondary sources, many of which offer interpretations that are not in full agreement with the author’s own. The bibliography and index are also extensive.

In short, this is a serious scholarly work that represents an intellectual challenge to the reader. There is a good deal of specialized vocabulary and there are historical, philosophical, and theological references that are not fully explained. The use of accurate but antiquated chemical nomenclature presents difficulties to the modern reader. Fortunately the author judiciously uses modern chemical names, formulas, and equations, sometimes in footnotes and sometimes in the text, to help elucidate the narrative without introducing excessive anachronisms.

Chemists will be especially interested in Schofield’s verdict on Priestley as a scientist. By his own admission, Schofield is more sympathetic to his hero’s scientific work and more critical of Lavoisier than are many modern historians of chemistry. However, we read (on p 193): “Priestley was never a chemist; in a modern, and even a Lavoisian, sense, he was never a scientist. He was a natural philosopher, concerned with the economy of nature and obsessed with an idea of unity, in theology and in nature.” Indeed, some of the difficulties Priestley had in accepting the new French chemistry were a consequence of his rather sketchy knowledge of chemical phenomena and his skepticism about the importance of weight relationships in chemistry. And there were honest and challenging experimental problems, for example confusion about the identity and properties of “inflammable gas”, which in some experiments we now recognize to have been hydrogen, and in others carbon monoxide, and in still others a mixture of the two.

But Priestley’s obsession with an all-encompassing unity was also a major explanation of his apparent intransigence. This may seem counter intuitive, given the prevailing image of Priestley as a religious and political radical but a chemical conservative. To modern eyes, his explanations of combustion, the reactions of gases, the composition of water, and the supposed conversion of water into air seem fraught with contradictions. But he saw the inconsistencies in the new chemistry that Lavoisier and his friends (and his 21st century followers) overlooked or ignored. Many of Lavoisier’s postulates were soon disproved: oxygen is not present in all acids (though it is present in water, which is neutral), hydrogen does not form only from water, light and heat are not elements, and so on. Priestley failed to recognize that the new system of chemistry was not dependent on such details, but its strength lay in its ability to encompass and explain a wide variety of reactions and phenomena. As late as 1800, in his last assault on the antiphlogistonists, The Doctrine of Phlogiston established and that of the Composition of Water refuted [sic], Priestley addressed the French chemists, trusting “that your political revolution will be more stable than this chemical one”. But by then the revolution was essentially over and chemistry was forever changed.

Even if Joseph Priestley were not the immigrant icon of the American Chemical Society, there would be ample reason to learn about his fascinating life and contributions. I know of no better resource that this remarkable two-volume set.

Literature Cited

1. Schofield, R. E. The Enlightenment of Joseph Priestley: A Study of His Life and Works from 1733 to 1773; Pennsylvania State University Press: University Park, PA, 1997.
2. Jensen, W. B. J. Chem. Educ. 1999, 76, 321.
3. Schwartz, A. T. Phys. Perspect. 2001, 3, 495–496.