William John Macquorn Rankine (1853) "On the General Law of the Transformation of Energy," Proceedings of the Philosophical Society of Glasgow, vol. 3, no. 5, pages 276-280; reprinted in: (1) Philosophical Magazine, series 4, vol. 5, no. 30, pages 106-117 (February 1853); and (2) W. J. Millar, ed., Miscellaneous Scientific Papers: by W. J. Macquorn Rankine,... (London, England: Charles Griffin and Co., 1881), part II, pages 203-208: "The law of the Conservation of Energy is already known—viz. that the sum of all the energies of the universe, actual and potential, is unchangeable."
William John Macquorn Rankine (1853) "On the General Law of the Transformation of Energy," Proceedings of the Philosophical Society of Glasgow, vol. 3, no. 5, pages 276-280; reprinted in: (1) Philosophical Magazine, series 4, vol. 5, no. 30, pages 106-117 (February 1853); and (2) W. J. Millar, ed., Miscellaneous Scientific Papers: by W. J. Macquorn Rankine,... (London, England: Charles Griffin and Co., 1881), part II, pages 203-208: "The law of the Conservation of Energy is already known—viz. that the sum of all the energies of the universe, actual and potential, is unchangeable."
Laertius, Diogenes. Lives of Eminent Philosophers: Epicurus. .. This passage comes from a letter quoted in full by Diogenes, and purportedly written by Epicurus himself in which he lays out the tenets of his philosophy.
