Recent Theories of Electricity. - 201 



expense of: creating a kind of matter entirely outside of, and 

 contradictory to, anything in onr experience. We have 

 only to recall the properties ascribed to this sether to find 

 that it operated equally well if it had a density indefinitely 

 great or one indefinitely small ; if it were rigid or if it 

 were collapsible, &c. As certainly as one physicist endowed 

 it with a property, another arose who showed that just the 

 opposite property was equally efficient. Yet we might still 

 be staggering along with the conviction that somehow this 



op © O 



supposititious stuff was of use to us ; at least it gave us a 

 set of words conveying some meaning. But when Maxwell 

 proved mathematically that a third kind of radiant energy 

 of an electrical type should be looked for, and when Hertz 

 demonstrated its existence, no elastic solid would serve for 

 all three kinds ; and so, for a time, we were taught simul- 

 taneously the properties of two co-existent aethers. An 

 elastic-solid and a so-called electromagnetic sether in one 

 space were not amicable, and the former soon acted as 

 Lord Kelvin had suggested, it really collapsed. Maxwell's 

 idea produced a revolution in the theory of physics; heat 

 and light remained no longer a form of mechanical waves 

 but became electromagnetic waves of special periodicity. 

 By a progressive subtilization we have now arrived at 

 Sir J. Larmor's celebrated definition of aether which w r ill 

 satisfy all forms of radiant energy. The aether * is " a 

 plenum with uniform properties throughout all extension, but 

 permeated by intrinsic singular points, each of which deter- 

 mines and, so to speak, locks up permanently a surrounding- 

 steady state of strain or other disturbance.-" This plenum is 

 continuous, without atomic structure, and absolutely quies- 

 cent. Since these points of intrinsic strain are the atoms of 

 matter, " the f ultimate element of material constitution 

 being taken to be an electric charge or nucleus of permanent 

 setherial strain," it is evident " that | the motion of matter 

 does not affect the quiescent aether except through the motion 



of the atomic electric charges carried along with it." These 



• 



ideas evidently reduce matter to an attribute of electricity, 



and make all forces of the type called electrical forces. 



But if electricity is everything, we must inevitably some 



time explain pure mechanical actions in terms of this 



electrical substance. Sir J. Larmor clearly foresees this, 



as shown by his statement § : "The electric character of the 



forces of chemical affinity was an accepted part of the 



chemical views of Davy, Berzelius, and Faraday ; and more 



* ' zEther and Matter,' p. 77, 



t L. c. p. 27. + L. c. p. 2. § L. c. p. 1C5. 



