Lives of the Philosophers of the Time of George III., by Henry, Lord Brougham, F.R.S., p. 106. London, 1855.
 Experiments and Observations on Different Kinds of Air, by Joseph Priestley (3 vols.). Birmingham, 790, vol. II, pp. 103-107.
 Lectures on Experimental Philosophy, by Joseph Priestley, lecture IV., pp. 18, ig. J. Johnson, London, 1794.
 Translated from Scheele's Om Brunsten, eller Magnesia, och dess Egenakaper. Stockholm, 1774, and published as Alembic Club Reprints, No. 13, 1897, p. 6.
 According to some writers this was discovered by Berzelius.
 Histoire de la Chimie, par Ferdinand Hoefer. Paris, 1869, Vol. CL, p. 289.
 Elements of Chemistry, by Anton Laurent Lavoisier, translated by Robert Kerr, p. 8. London and Edinburgh, 1790.
CHAPTER III. CHEMISTRY SINCE THE TIME OF DALTON