XII. 5] MAGNETIC TUBES IN ROTATION 169 
as complementary to the system under discussion. Either of 
these models would satisfy the requirements of experimental 
work, such as that of Stern and Gerlach, necessitating both 
magnetic and electric characteristics in the fundamental physical 
entities. 
According to the hypothesis advanced each quantum tube may be 
regarded as a potential electron. In Chapter X it was suggested that 
the emission of radiation consisted in, or was consequent upon, 
the liberation of a quantum tube from an atomic or molecular 
system. Taking this suggestion in connection with the present 
hypothesis some light is thrown on the remarkable reciprocal 
relation between radiation and electrons. With characteristic 
boldness Sir Oliver Lodge * has discussed this problem in an 
address on .¿Ether and Electrons and suggested that the actual 
generation of an electron by means of light is not an altogether 
impossible idea. 
We may anticipate one result from a later chapter and men 
tion that de Broglie has postulated an “internal process” of a 
definite frequency in connection with any moving particle. On 
the theories advanced by de Broglie, Einstein, and Schródinger, 
electrons, both positive and negative, and light quanta all alike 
involve periodic phenomena. Such a conception is in harmony 
with the present conception of magnetic tubes possessing an 
internal spin of assigned frequency. Again, J. D. van der Waals f 
has suggested that this view of the periodic character of atomic 
structure can be expressed so as to involve spatial limitations 
of the atoms, just as we have found limits to the size of the 
positive or negative electron. 
The picture of an atomic nucleus suggested by the foregoing 
considerations is that of a set of magnetic tubes rotating 
about a common axis with the same angular velocity, some of 
the tubes representing positive, the remainder, and smaller 
number negative electrons. 
Outside the nucleus we should expect to have in addition a 
set, or sets, of outer magnetic tubes, of larger size, rotating or 
capable of rotating about the same axis so as to give rise to the 
external magnetic and electric field due to the atom. These 
tubes may be supposed to rotate with very much smaller angular 
velocity than the inner set. For instance, they might have an 
angular velocity comparable with that of the radius vector to 
an electron in one of the Bohr orbits. In that case the mass to 
be associated with these outer tubes would be very small in com 
parison with the mass of the nucleus. 
Finally these results and suggestions may be considered in 
* Sir Oliver Lodge, Nature, vol. 112, p. 185, August 4, 1923. 
f van der Waals, K. Akad. Amsterdam, Proc., vol. 29, p. 899, 1926«