1. Josiah Wedgwood (1730–95) — Scientist
2. J. Wedgwood,Catalogue of Cameos, Intaglios, Medals . with a General Account of Tablets . and other Ornamental and Useful Articles, 6th edition with additions, Etruria, 1787, p. 69.
3. J. Priestley,Experiments and Observations on Different Kinds of Air, London, 1777, vol. 3, pp. 28–40.
4. J. Wedgwood and T. Bentley,A Catalogue of Cameos, Intaglios, Medals . withaGeneral Account of Vases and other Ornaments after the Antique, 5th edition with additions, London, 1779, p. 60. A similar statement appears in the 6th French edition, London, 1779, p. 93.