Experiments on tribo-electricity. I.—The tribo-electric series

I.- Historical . Little exact knowledge of tribo-electricity has yet been accumulated, and this subject has certainly not been raised to the dignity of a quantitative science. In the present paper will be found an account of experiments in which the conditions of the solid bodies rubbed together have been greatly varied. Thus, temperature has been changed both before and during friction; the surfaces used have been rubbed with considerable pressure while hot; they have, wherever possible, been rubbed together when flexed; and they have been prepared before rubbing by being ground and polished in various ways. Much information has thus come to light as to the electrical surface conditions of a variety of solids. Before setting forth the methods and results of this paper, let us note the information previously available. Good summaries of the subject will be found in Wiedemann's 'Electriciat' (2) and Chwolson's treatise. (1).