Phases of physics in J. D. Forbes' Dissertation Sixth for the Encyclopaedia Britannica (1856).

This paper takes James David Forbes' Encyclopaedia Britannica entry, Dissertation Sixth, as a lens to examine physics as a cognitive, practical, and social enterprise. Forbes wrote this survey of eighteenth- and nineteenth-century mathematical and physical sciences between 1852 and 1856, when British "physics" was at a pivotal point in its history, situated between a field identified by its mathematical methods - originating in France - and a discipline identified by its university laboratory institutions. Contemporary encyclopedias provided a nexus for publishers, the book trade, readers, and men of science in the formation of physics as a field. Forbes was both a witness, whose account of the progress of physics or natural philosophy can be explored at face value, and an agent, who exploited the opportunity offered by the Encyclopaedia Britannica in the mid nineteenth century to enroll the broadly educated public and scientific collective, illuminating the connection between the definition of physics and its forms of social practice. Forbes used the terms "physics" and "natural philosophy" interchangeably. He portrayed the field as progressed by the natural genius of great men who curated it within an associational culture that engendered true intellectual spirit. Although this societal mechanism was becoming ineffective, Forbes did not see university institutions as the way forward. Instead, running counter to his friend William Whewell, he advocated inclusion of the mechanical arts (engineering), and a strictly limited role for mathematics. He revealed tensions when the widely accepted discovery-based historiography conflicted with intellectual and moral worth, reflecting a nineteenth-century concern with spirit that cuts across twentieth-century questions about discipline and field.