290 WHAT 18 LIFE 



the view that electricity is atomic. In 1871 Wilhelm 

 Weber wrote of positive and negative electrical 

 particles. In 1873 J. Clerk Maxwell, in referring to 

 Faraday's experiments (which showed that the 

 quantity of electricity carried by an atom in elec- 

 trolytic conduction is exactly proportional to the 

 valency of the atom), spoke of a "molecule of 

 electricity," but deemed it "extremely improbable" 

 that the "theory of molecular charges" would be 

 retained. In his Faraday lecture at the Royal In- 

 stitution (1881) Helmholtz expressed the belief that 

 electricity is atomic on the basis of Faraday's dis- 

 coveries. However, Helmholtz did not feel prepared 

 to embrace all electrical phenomena in his atomic 

 view. Faraday himself did not use his own remark- 

 able data to further an atomic theory of electricity. 

 Dr. G. Johnstone Stoney did use the facts of 

 ions in solutions brought to light by Faraday as his 

 starting point, and, in 1874, developed clearly the 

 theory of the atomic nature of electricity. He even 

 estimated the value of the elementary electrical 

 charge, and his estimate shows a surprising ap- 

 proach to the later accurately determined values. 

 Stoney also, in 1891, first suggested the word "elec- 

 tron" (Greek elektron, amber) as a name for the 

 "natural unit of electricity." 



Much theoretical work was done on the electron, 

 notably by Sir Joseph Larmor and by H. A. Lorentz. 

 The discovery of cathode rays for the first time in 

 history revealed pure negative electricity. "Before 

 we had found only electrical bodies," said P. Lenard, 

 "but never electricity itself." But in 1897 the great 

 Lord Kelvin, though expressing his preference for 

 "an atomic theory of electricity," still admitted the 

 possibility that electricity might be "a continuous 

 homogeneous liquid." 



