Produced by Marius Masi, Don Kretz, Juliet Sutherland, and the Online Distributed Proofreading Team at https://www.pgdp.net Transcriber's notes: (1) Numbers following letters (without space) like C2 were originally printed in subscript. When letters are subscripted, they are preceded by an underscore, like C_n. (2) Characters following a carat (^) were originally printed in superscript. (3) Letters topped by Macron are represented as [=x]. (4) [oo] stands for infinity; [int] for integral; [alpha], [beta], etc. for greek letters. (5) The following typographical errors have been corrected: Page 871: "an equation which is very useful, because it enables us, if we know the distribution." 'because' amended from 'becaus'. Page 890: "The colour of the luminosity due to positive rays is not in general the same as that due to anode rays." 'positive' amended from 'postive'. Page 890: "Anode Rays.--Gehrcke and Reichenhein (Ann. der Phys. 25, p. 861) have found that when the anode consists of a mixture of sodium and lithium chloride." 'mixture' amended from 'mixure'. ENCYCLOPAEDIA BRITANNICA A DICTIONARY OF ARTS, SCIENCES, LITERATURE AND GENERAL INFORMATION ELEVENTH EDITION VOLUME VI, SLICE VIII Conduction, Electric Article in This Slice: CONDUCTION, ELECTRIC CONDUCTION, ELECTRIC. The electric conductivity of a substance is that property in virtue of which all its parts come spontaneously to the same electric potential if the substance is kept free from the operation of electric force. Accordingly, the reciprocal quality, electric resistivity, may be defined as a quality of a substance in virtue of which a difference of potential can exist between different portions of the body when these are in contact with some constant source of electromotive force, in such a manner as to form part of an electric circuit.