24 PHYSICS 



The question of the ultimate structure of matter, as has already 

 been pointed out, is also speculative in the sense that the mechanism 

 upon which its properties are based is out of the range of direct 

 observation. For the older chemistry and the older molecular physics 

 the assumption of an absolutely simple atom and of molecules com- 

 posed of comparatively simple groupings of such atoms sufficed. 

 Physical chemistry and that new phase of molecular physics which 

 has been termed the physics of the ion demand the breaking up of 

 the atom into still smaller parts and the clothing of these with an 

 electric charge. The extreme step in this direction is the suggestion 

 of Larmor that the electron is a " disembodied charge" of negative 

 electricity. Since, however, in the last analysis, the only conception 

 having a definite and intelligible mechanical basis which physicists 

 have been able to form of an electric charge is that which regards it 

 as a phenomenon of the ether, this form of speculation is but a return 

 under another name to views which had earlier proved attractive to 

 some of the most brilliant minds in the world of science, such as 

 Helmholtz and Kelvin. The idea of the atom, as a vortex motion 

 of a perfect fluid (the ether), and similar speculative conceptions, 

 whatever be the precise form of mechanism imagined, are of the 

 same class as the moving electric charge of the later theorists. 



Lodge, 1 in a recent article in which he attempts to voice in a pop- 

 ular way the views of this school of thought, says: 



"Electricity under strain constitutes 'charge'; electricity in loco- 

 motion constitutes light. What electricity itself is we do not know^ 

 but it may, perhaps, be a form or aspect of matter. . . . Now we can 

 go one step further and say, matter is composed of electricity and of 

 nothing else. . . ." 



If for the word electricity in this quotation from Lodge we substi- 

 tute ether, we have a statement which conforms quite as well to the 

 accepted theories of light and electricity as his original statement 

 does to the newer ideas it is intended to express. 



This reconstructed statement would read as follows: 



Ether under strain constitutes "charge "; ether in locomotion con- 

 stitutes current and magnetism; ether in vibration constitutes light. 

 What ether itself is we do not know, but it may, perhaps, be a 

 form or aspect of matter. Now we can go one step further and say : 

 "Matter is composed of ether and of nothing else." 



The use of the word electricity, as employed by Lodge and others, 

 is now much in vogue, but it appears to me unfortunate. It would 

 be distinctly conducive to clearness of thought and an avoidance of 

 confusion to restrict the term to the only meaning which is free from 

 criticism; that in which it is used to designate the science which 

 deals with electrical phenomena. 



1 Lodge, Harper's Magazine, August, 1904, p. 383. 



