62 POPULAR SCIENCE MONTHLY. 



definite and intelligible mechanical basis which physicists have been 

 able to form of an electric charge is that which regards it as a phe- 

 nomenon 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 pre- 

 cise form of mechanism imagined, are of the same class as the moving 

 electric charge of the later theorists. 



Lodge* in a recent article in which he attempts to voice in a popular 

 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 con- 

 fusion 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. 



The only way in which the noun electricity enters, in any definite 

 and legitimate manner into our electrical treatises is in the designation 

 of Q in the equations 



Q=fldt, C=--Qj£, W=QE, etc. 



Here we are in the habit — whether by inheritance from the age of the 

 electric fluid, by reason of the hydrodynamic analogy or as a matter of 

 convention or of convenience merely — of calling Q the quantity of 

 electricity. 



Now Q is ' charge ' and its unit the coulomb is unit charge. The 

 alternative expression, quantity of electricity, is a purely conventional 

 designation and without independent physical significance. It owes its 



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



