624 Prof. J. Larmor on the ascertained Absence 
electrons, and the idea of force acting between them and the 
eether is dispensed with. : 
If, then, matter is for physical purposes a purely ethereal 
system, if it is constituted of simple polar singularities or 
electrons, positive and negative, in the Maxwellian ether, 
the nuclei of which may be either practically points or else 
small regions of zther with internal connexions of pure con- 
straint, the propositions above stated for the first order are 
extended to the second order of v/c, with the single addition 
of the FitzGerald-Lorentz shrinkage in the scale of space, 
and an equal one in the scale of time, which, being isotropic, 
is unrecognizable. 
On such a theory as this the criticism presents itself, and 
was in fact at once made, that one hypothesis is needed to 
annul optical effects to the first order ; that when these were 
found to be actually null to the second order another hypo- 
thesis had to be added; and that another hypothesis would 
be required for the third order, while in fact there was no 
reason to believe that they were not exactly null to all orders. 
Such a train of remarks indicates that the nature of the 
hypotheses has been overlooked. And if indeed it could be 
proved that the optical effect is null up to the third order, 
that circumstance would not demolish the theory, but would 
rather point to some finer adjustments than it provides for : 
needless to say the attempt would indefinitely transcend 
existing experimental possibilities. 
As, then, the theory contains no further power of imme- 
diate adaptation, what are the hypotheses on which it rests, 
and how far are they gratuitous hypotheses introduced for 
this purpose alone? Up to the first order the electron hypo- 
thesis, that electricity is atomic, suffices by itself, as Lorentz 
was the first toshow, Yet, even if the nature of the particles 
of the cathode discharge had never been made out, and the 
Zeeman effect had never been discovered, the facts known to 
Ampere and Faraday were sufficient to demonstrate that no 
other conception of electricity than the atomic one is logically 
self-consistent *. 
Up to the second order the hypothesis that matter is con- 
stituted electrically—of electrons—is required in addition. 
For this there is no independent evidence except perhaps the 
general simplicity of the correlations of physical law. The 
circumstance that positive electrons have not yet been 
isolated naturally counts considerably on the other side ; yet 
the theory puts no limit to the size and inertia and complexity 
of an electron, it only prescribes that it must be a collocation 
of zther poles connected together by some sort of pure con- 
straint, but with no extraneous activities. 
* Cf. ‘ Aither and Matter,’ p. 337. 
