The contribution of the physiologist, William Benjamin Carpenter (1813--1885), to the development of the principles of the correlation of forces and the conservation of energy.

Over a dozen natural philosophers of the first half of the nineteenth century have been discussed by historians of science as possible contributors to the emergence of the doctrine of the conservation of energy. One figure who has not been discussed, yet who was deeply interested in the twin principles of the correlation of forces and the conservation of power and attempted to apply them in his work as a physiologist, was William Benjamin Carpenter (1813-1885), one of the most eminent physiologists in Britain during the mid-century. This paper traces the development of his ideas on force through the first forty years of his career, from the mid 1830s to the 1870s, examining a wide selection of his work. Carpenter's ideas on force were initially tentative; but as experimental evidence accumulated from both the life-sciences and the physical sciences, especially from the work of Justus Liebig, William Robert Grove, and Carlo Matteucci, his ideas became more explicit so that by the 1850s they became the basis for his physiology. By then, power or force (these two words were still often used interchangeably) and their principles of conservation and correlalation had become paradigmatic in his physiology, just as they had become key concepts for certain natural philosophers in the physical sciences. Correlation was always the main principle for Carpenter, even after he had heard of, and was acknowledging the brilliance of, Mayer's work on conservation. In seeing the conservation principle as subordinate to and, in a sense, contained within the correlation doctrine, Carpenter exemplifies the idea now current among historians of science that a so-called "simultaneous discovery" is rarely, if ever, simultaneous. Rather, an apparently simultaneous discovery is usually a coming together of disparate lines of investigation, where the different investigators ask different sets of questions; and it is only in hindsight that they appear to address themselves to a single core-idea or discovery. DURING THE last two decades several studies have appeared on the emergence of the idea of energy conservation during the early-mid nineteenth century. The seminal Vance M. D. Hall, B.A., D.I.C., M.Sc., Ph.D., Department of History of Science, The Open University, Walton Hall, Milton Keynes, Bucks., MK7.