﻿The Gyroscopic Theory of Atoms and Molecules. 311 



principle that when an electrical charge is in motion, it 

 possess s an apparent mass that increases ^ith the velocity, 

 and implies that all mass is due to this electromagnetic 

 origin. For high velocities, one-tenth or more of that of 

 light, experimental measurements show an agreement with 

 this theory. The suggestion has been made that perhaps 

 this electromagnetic mass constitutes the whole o£ the mass, 

 and we do not, therefore, need to assume anything else. 

 It is probable that the velocities of the electrons in the atoms 

 are of an order of 1/700 that of light, and to apply the 

 above result to them extends the law far beyond the range 

 of experimental evidence. The theory is. moreover, usually 

 applied to the positive electricity in the atom which is 

 supposed to be relatively at rest, a condition as far removed 

 as possible from the experimental observation. It requires 

 that as neutral atoms grow heavier with the addition of 

 electrons, the positive nucleus must grow rapidly larger in 

 radius to show increasing mass, the radius being directly 

 proportional to the number of electrons or to the mass, unless 

 som* supposition is introduced which prevents the positive 

 electricity from amalgamating as it were, and preserves the 

 individual positive electrons so that their radii are not 

 changed, and the mass is increased by the additional numbers 

 of them. If this is th^ case, it is difficult to understand the 

 nature of the forces th t hold them together, and I am not 

 aware that any definite hypothesis on this point has ever 

 been suggested. That some such thing must be the case 

 seems to be required by the experimental fact that when an 

 atom breaks up in radioactive transformations, atoms of 

 helium are liiven off, each contai ing an exact multiple of 

 the smallest positive charge. On the whole, this conception 

 that the principal mass is due to that substance which fills 

 the smallest volume, and that the radius varies directly with 

 the mass or number of electrons, is very unnatural. This 

 makes the volume eight times as much for double the mass. 



On the theory here advanced, the mass of the atom is 

 shown to be proportional to the volume of the positive 

 electricity. This volume is first determined by independent 

 means, and when compared with the approximate volume of 

 the electron, the ratio is the same ;is the ratio between the 

 masses of the atom and the mass of electrons composing it, 

 about 1900. On this theory the mass per unit volume 

 everywhere, whether of positive or of negative electricity, at 

 slow velocities is the same and is constant, approximately 

 equal to 10 12 grams per cubic centimetre, as is shown in 

 a subsequent section. 



