
of Effects of Motion through the Atther. 625 
Any rival theory must on the threshold give an account 
of the Michelson null optical result, of Tr outon’s null electric 
result for convection of a charged aioncor *, and of Ray- 
leigh’s absence of double refraction now rendered thoroughly 
secure by Brace fT. 
As electrons are already held to be a reality on various 
erounds, theoretical and experimental, it would appear there- 
fore that there is much to be said for a benevolent attitude 
to the proposition that all the interactions of matter, so far as 
the laws of physics and chemisiry extend, are to be described 
as phenomena occurring in and through the ether, and thus 
differentiated from the more recondite world of vital growth 
and change which they make manifest to our senses. This 
principle does not yet, so far as one can see, stand in the 
way of any other branch of physical science, while it accounts 
for the very remarkable absence of influence of the earth’s 
motion through space on the most sensitive phenomena, and 
is almost led up to thereby. 
Itis pertinent to the present subject to refer to Mr. Suther- 
land’s recent remarks (Phil. Mag. April, p. 406) on the 
magnetic effect of electric conv ection, in relation to the mys- 
terious action of a dielectric varnish that has been announced 
by Crémieu and Pender. The discrepancy in the conser- 
vation of energy, there described, applied to the domain of 
electric polarization, is too startling to have been over- 
looked by the current theory f ; and accordingly closer con- 
sideration gets rid of the difficulty. When an electron e 
is transferred in an electric field from a place where the 
potential is V, to a place where it is V>», the force acting on 
it, being e multiplied by the gradient of V, does work equal 
to e(V,;—V.). When, however, the electron is embedded in 
a piece of dielectric matter which is so transferr ed, the force 
acting on the electron itself is diminished by the presence of 
the surrounding polarized matter, and so the work done on 
the electron is less than before: but now the electric polari- 
zation induced by the electron in this surrounding matter is 
also acted on by the electric field, and if we add the work 
_ done on it during the movement, we shall get the same total 
work as before for the system that is moved, and there will 
be no discrepancy to be otherwise explained. 
Cambridge, April 7, 1904. 
* Phil. Trans. 1903. 
+ The null influence on optical rotation, observed by Rayleigh, counts 
here as a first-order effect. 
t Cf. Phil. Trans, 1897 A, p. 248, and ‘ Atther and Matter,’ 1900, 
Appendix A. 
Phil. Mag. 8. 6. Vol. 7. No. 42. June 1904. 2U 
