a table of
is given in Part II. [p. 32]
To test the stability of the system we have to consider displacements of the orbits of the electrons relative to the nuclei, and also displacements of the latter relative to each other.
A calculation based on the ordinary mechanics gives that the systems are unstable for displacements of the electrons in the plane of the ring. As for the systems considered in [Part II.], we shall, however, assume that the ordinary principles of mechanics cannot be used in discussing the problem in question, and that the stability of the systems for the displacements considered is secured through the introduction of the hypothesis of the universal constancy of the angular momentum of the electrons. This assumption is included in the condition of stability stated in [§1]. It should be noticed that in [Part II.] the quantity
was taken as a constant, while for the systems considered here,
, for fixed positions of the nuclei, varies with the radius of the ring. A simple calculation, however, similar to that given in Part II. on [p. 30], shows that the increase in the total energy of the system for a variation of the radius of the ring from a to
