198 



SCIENTIFIC THOUGHT. 



59. 



Objections 

 raised by 

 atomists. 



The propounders of this atomic view of electricity 

 very naturally look with little favour on those other 

 theories which, under the name of energetics or pheno- 

 menology, would restrict the method of science to the use 

 of only such quantities and data as can be actually seen 

 and directly measured, and which condemn the introduc- 

 tion of such useful conceptions as the atom, the electron, 

 and the ether, which cannot be directly seen and can 

 only be measured by indirect processes; and there is 

 no doubt that the century ends with a very emphatic 

 assertion of the rights and the legitimacy of the atomic 

 and mechanical views of nature, regarding the energy 

 principle as a regulative but not, by itself, a constructive 

 method of research and progress ; for, as Dr Larmor says, 

 " If a molecular constitution of matter is fundamental, 

 energy cannot also be so." l Nevertheless, though in 

 many ways opposed, the two views of nature meet at 

 least in one important point. Both theories have been 



dans le champ maguetique ? Ici 

 encore, la theorie vint aider 1'ex- 

 perience ; cette fois, c'est a H. A. 

 Lorentz que 1'on est redevable du 

 re"sultat obtenu. II est juste de 

 dire que d'autres considerations, 

 par exemple celle de Lord Kelvin " 

 (see Tait, Proc. Royal Soc., Edin- 

 burgh, 1875-76, p. 118) "auraient 

 pu, elles aussi, probablement con- 

 duire a cette de"couverte de la 

 polarisation des raies. Mais en 

 fait, cette de"couverte a e"te faite 

 grace a 1'intervention de la theorie 

 des ' ions ' de H. A. Lorentz. Dans 

 cette theorie, dit M. Zeemann, on 

 admet qu'il existe dans tous les 

 corps de petites masses e'lectrise'es, 

 ou 'ions,' dont les mouvements 

 constituent tous les ph^nomenes 

 electriques ; les vibrations lum- 

 ineuses seraient des vibrations de 

 ces ions. L'e"tat de Father est 



de"tennine entierement par la 

 charge, la position et le mouve- 

 ment de ces ions. . . . M. Lorentz 

 fit remarquer que les bords des 

 raies elargies devaient etre pol- 

 arises. L'expeYience permit a 

 Zeemann de verifier cette conclu- 

 sion de Lorentz" (p. 37). 



1 ' ^Ether and Matter,' p. 286 : 

 " One effect of admitting a mole- 

 cular synthesis of dynamical prin- 

 ciples ... is to depose the concep- 

 tion of energy from the fundamental 

 or absolute status that is sometimes 

 assigned to it. ... We can know 

 nothing about the aggregate or total 

 energy of the molecules of a ma- 

 terial system, except that its numeri- 

 cal value is diminished in a definite 

 manner when the system does me- 

 chanical work or loses heat. The 

 definite amount of energy that plays 

 so prominent a part in mechanical 



