i68 
THE QUANTUM [ xn . 5 
should be noticed that on these assumptions the size of a negative 
electron does not differ from the size of a positive electron, the 
radius being a quantity of the same order of magnitude as the 
estimate of the radius of an atomic nucleus obtained by Rutherford 
from experiments on the scattering of a particles. The radius 
of the negative electron on the classical theory is well known 
to be a quantity larger than this, but that estimate is derived 
from the assumption that the electron may be treated as a 
charged sphere. 
Although no quantitative explanation has yet been found 
for the frequencies v r and v 8 , which have been assigned so as to 
give the masses actually observed, it may be suggested that they 
are in some way determined by the limiting condition that the 
velocity of the extreme edge of the rotating tube cannot exceed 
the velocity of light. 
It is interesting to compare with the suggestions here made 
a surmise as to the relation between positive and negative 
electricity put forward independently by Sir Oliver Lodge in 
his Presidential Address to the Röntgen Society on November 6, 
1923. 
“ Let us suppose then that round the nucleus of an atom the 
aether is in a state of violent rotation. It might even be suggested 
that a proton itself is always and constitutionally in a state of 
circulation at a speed comparable to the velocity of light, and 
that in this way its mass is accounted for, as distinguished from 
the much smaller mass of the electron, which presumably is not 
in a state of rotation. We might go so far as to surmise—as 
indeed we do for many other reasons, connected with the trans 
mission of waves by a vortex filled medium—that the normal 
aether contains a constitutional rotation comparable to the 
velocity of light, and that upon this, when a pair of electric 
units are being somehow generated, two equal opposite rotations 
are superposed ; one in opposition to the original rotation, giving 
a net result zero ; the other in the same direction, giving a result 
slightly nearer to the velocity of light than before, conceivably 
sufficient to cause what would otherwise be the mirror-image 
of the negative electron to have a mass 1,850 times as big.” 
5. Discussion of the Electronic Models 
The fundamental electric charge here postulated possesses 
axial and not spherical symmetry. Further, it exhibits magnetic 
as well as electric properties. It is indeed a “ magneton ” which 
serves also as an “ electron.” The spinning electron (Chapter 
XVI) employed by Goudsmit and Uhlenbeck may be regarded