﻿Gyroscopic Theory of Atoms and Molecules. <\29 



of these phenomena. When ordinary light falls upon a body 

 under the proper conditions electrons are emitted. The 

 velocity of each electron emitted is independent of the 

 intensity, but depends directly upon the frequency of the 

 light. The number of emitted electrons depends upon the 

 light energy or intensity, but the velocity of the individual 

 electron does not. The slightest change in the frequency of 

 the light produces a corresponding change in the emitted 

 velocity, and the velocity is a continuous function of the 

 frequency. No form of atom which is only capable of reso- 

 nance at particular fixed frequencies peculiar to itself would be 

 capable of such response to external forces. The gyroscopic 

 nature of the atom, however, renders it capable of responding 

 to the frequency of the impressed force. An analogous case 

 is to be found in the precessional motion of the earth due to 

 the comparatively slow revolution of the sun or the moon 

 in an orbit inclined to the plane of the equator, so that the 

 gyroscopic couple acting upon the earth varies with the 

 position of the sun or moon. It is well known that this 

 produces a periodic motion of the earth's axis corresponding 

 to twice the frequency of the orbital revolution of the sun 

 or moon. There is, similarly, produced in each atom upon 

 which the light falls a frequency double that of the light. 

 Let fig. 4 represent the single electron atom 

 upon which light is falling in the direction 

 indicated. If we imagine that the light pro- 

 duces a pressure upon the electron, perhaps 

 in just the way that it produces a pressure 

 upon any small particles, then this pressure 

 will vary harmonically with the time eorre- 

 sponding with the frequency of the light. This 

 is a very low frequency compared with that 

 of the electron in its orbit, and it will produce 

 a precession of the pole of the orbit having twice the 

 frequency of the impressed force, the light pressure. 



The energy so received from the light may accumulate 

 until an electron escapes. This is likely to happen always at 

 a critical velocity which is fixed hy the character of the atom 

 rather than the intensity of the light and so not vary with 

 the light intensity. The energy, however, is abstracted from 

 the light. A greater light energy merely brings an in- 

 creasing number of electrons up to the critical point where 

 they quit the atom. A calculation of the manner in which 

 the electron may be ejected, especially in a complex atom, 

 is not undertaken at present, involved as it is with the 

 intricate precessional motions of the electrons. We are 



