J. P. Joule (1884). “Matter, Living Force, and Heat” (PDF). The Scientific Papers of James Prescott Joule. 2. The Physical Society of London. p. 274. https://ia802301.us.archive.org/33/items/scientificpapers01joul/scientificpapers01joul.pdf. "I am inclined to believe that both of these hypotheses will be found to hold good,—that in some instances, particularly in the case of sensible heat, or such as is indicated by the thermometer, heat will be found to consist in the living force of the particles of the bodies in which it is induced; whilst in others, particularly in the case of latent heat, the phenomena are produced by the separation of particle from particle, so as to cause them to attract one another through a greater space."
J. P. Joule (1884). “Matter, Living Force, and Heat” (PDF). The Scientific Papers of James Prescott Joule. 2. The Physical Society of London. p. 274. https://ia802301.us.archive.org/33/items/scientificpapers01joul/scientificpapers01joul.pdf. "I am inclined to believe that both of these hypotheses will be found to hold good,—that in some instances, particularly in the case of sensible heat, or such as is indicated by the thermometer, heat will be found to consist in the living force of the particles of the bodies in which it is induced; whilst in others, particularly in the case of latent heat, the phenomena are produced by the separation of particle from particle, so as to cause them to attract one another through a greater space."
