The appearance of Priestley's electrical work as a brief and irrelevant prelude to his more substantial chemical enquiries may explain why it has been strangely overlooked by historians of science. It was only fairly recently that Sir Philip Hartog sought to rectify this situation with the affirmation that ‘Priestley's electrical work offers the key to Priestley's scientific mind’. Attacking traditional chemical historiography for tracing Priestley's opposition to Lavoisier's theory to a deficiency in his scientific sensibilities, Hartog insisted that Priestley's natural philosophy can properly be understood only in relation to his ‘profound convictions on scientific method’ as fully expressed in the History of electricity. Only thus would Priestley's scientific thought be related correctly to his ‘work as a whole’.

The claim that the nineteenth century was a period of major transition for the relation between theology and natural science has become a historical truism. With its implications for the design argument and the doctrines of divine providence, Darwin's theory of evolution has rightly attracted the attention of scholars of Victorian science. Yet so much emphasis not only on Darwin himself, but on the life sciences generally, has tended to obscure some important issues concerning the relation of theology to natural science in the first half of the nineteenth century. As John Brooke has argued recently, natural theology in this pre-Darwinian period was far from being an essentially static, autonomous, and monolithic set of presuppositions about the existence of design in nature, but was, for various reasons, in a fragmented and disordered state. The general aim of the present note is to suggest some further dimensions to historical debates about the nature of natural theology, and in particular to emphasize the need for an examination of the physical sciences as well as the life sciences in this period.

Recently there has been considerable revaluation of the development of natural sciences in the early nineteenth century, dealing among other things with the works and ideas of Charles Lyell. The task of interpreting Lyell in balanced terms is extremely complex because his activities covered many fields of research, and because his views have been unwarrantably distorted in order to make him the precursor of various modern scientific positions. Martin Rudwick in particular has contributed several papers relating to Lyell's Principles of geology, and has repeatedly stressed the need for a comprehensive evaluation of Lyell's scientific proposals, and of his position in the culture of his time. In the present paper I hope to contribute to the reassessment of Lyell's work by concentrating on his discussion of transformism, which constituted the central theme of the second volume of the Principles of geology: the very length of Lyell's detailed and critical analysis of Lamarck's theories reveals the importance he attributed to the question of transformism in the contemporary natural sciences.