1. R. A. Millikan. The electron. In “Encyclopaedia Britannica,” 14th ed., Vol. VIII, p. 3361929
2. “The Electron.”;Millikan,1917
3. B. Franklin, “New Experiments and Observations on Electricity,” made at Philadelphia in America, and communicated in several letters to Mr. Collinson at London, F. R. S. London, printed and sold by E. Cave, at St. John's Gate, 1751 (reprinted, with a critical and historical introduction by I. Bernard Cohen, p. 213. Harvard University Press, Cambridge, Massachusetts, 1941. The date of the specific letter in which we are interested is given as 1749
4. L. Chernak, “Dissertatio physica de theoria electricitatis Franklini” Gröningen, 1771. I am obliged to Prof. L. Kürti, Director of the Debrecen College of the Reformed Church in Hungary, for providing me with a copy of this document.
5. J. Priestley, “The History and Present State of Electricity,” 3rd ed., London, 1755 (reprinted, Johnson Reprint, New York, 1966