This paper examines the activities of the Alsatian physicist–engineer and philosopher Gustave-Adolphe Hirn, whose contribution to thermodynamics and the metaphysical interpretation of heat theory are rather neglected parts of the history of French thermodynamics. The industrial environment in which Hirn was reared, and in which he worked, turned his thoughts to an investigation of thermal phenomena in conjunction with their relevance to the industrial needs of his factory. Nurtured in the intellectual environment of Colmar, Hirn also developed a deep sense of morality that was bound to the Christian world view. His work on heat led him to a generalized metaphysics based on the notion of force. However, despite important work on friction and his ‘independent’ discovery of the mechanical equivalent of heat, Hirn never felt that his work received its due recognition from his contemporaries. Without attributing this negligence solely to Hirn's relative isolation in Alsace and to the absence of formal institutional affiliations, the paper suggests that it was Hirn's particular scientific practice that was at odds with well-established practices employed by other French scientists and engineers.