222 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1935 



The inevitable process of reconciliation of these contradictory 

 theories was early begun by Lorentz/^ who suggested for this pur- 

 pose his electron theory of electricity. On this theory all the effects 

 of electricity inside bodies were explained on the assumption of elec- 

 trons, and all the effects of electricity at a distance, electrostatic, 

 electromagnetic, and inductive, required the help of the ether. To 

 unite these two classes of phenomena he assumed that each electron 

 was closely bound up with the ether, and that any change in config- 

 uration of the electrons produced a change in the ether which was 

 propagated with the velocity of light, and thus produced action at a 

 distance. 



About this time an entirely new line of experimental research was 

 developing which was destined eventually to make the atomic con- 

 cept of electricity dominant for a time. This was the study of the 

 electric discharge in high vacua. Several workers had investigated 

 this field without attracting much notice, but it remained for Crookes 

 to direct widespread attention to this class of phenomena by an exhi- 

 bition of novel and beautiful effects in vacuum tubes which he gave 

 ^t the meeting of the British Association at Sheffield in 1879. 

 Crookes unquestioningly assumed these effects to be due to electrified 

 molecules of residual gas in the tube. It was shown later by others 

 (J. J. Thomson, Townsend, Wilson, Millikan) that the negatively 

 charged particles in a Crookes tube were not molecules or even atoms, 

 but bodies of a minuteness previously unknown, about the l/1800th 

 part of a hydrogen atom in mass, and bearing a definite negative 

 charge of electricity. For these tiny bodies the term electron, intro- 

 duced by Stoney, was revived. Still later work brought to light the 

 proton, with an equivalent positive charge but larger mass than the 

 electron and, in our own day, the positive electron. 



As a result of this new line of investigation it became clear that 

 a great many electrical phenomena required the atomic theory of 

 electricity for their explanation. A great many, but not all; for a 

 large number refused to fall in line under a corpuscular explanation, 

 but could be simply and completely explained on Maxwell's theory 

 as ether disturbances. The discovery by Hertz of the electromagnetic 

 waves predicted by Maxwell did much to swing the pendulum back 

 in this direction. The reconciliation of these contending views has 

 bee*! carried on much along the line originally taken by Lorentz. 

 It is of interest to note that his idea of an electron inseparably bound 

 up with the ether is found today in all essentials in the theory of 

 wave mechanics. 



" Lorentz, Verslagen en Mededeelingftn der Koninklljke Akademie van Wetenschappen, 

 Amsterdam, vol. 8, pp. 323-327, 1891. Also Arch, Negrlandaises, vol. 25, p. 482, ch. 4, 

 1892, 



