98 Dr. C. V. Burton on a 



exerted on electrons. Again, experiment indicates unmis- 

 takably that, whatever the nature of positive and negative 

 electrons may be, they are far from being symmetrical 

 opposites. Thus it is natural to inquire what effects are to 

 be expected when we discriminate between positive and 

 negative electrons under gravitational influence. 



48. To take the simplest case, consider a body moving 

 without constraint in a uniform field of gravity, the accelera- 

 tion of the body /thus agreeing in direction and magnitude 

 with the strength of the field. Suppose that, electrically, the 

 condition of the body is not changing ; then on the whole 

 both positive and negative electrons are moving with the 

 acceleration /. Now if the forces exerted in a field of gravity 

 are in the same sense on positive and negative electrons, and 

 of magnitudes proportional respectively to the masses of such 

 electrons, the identical acceleration of the two denominations 

 will follow, without additional forces of electrostatic type 

 being called into play. But if the gravitational forces on 

 positive and negative electrons do not conform to the condition 

 just referred to, they can always be resolved into two sets : 

 one set of like forces proportional respectively to the masses 

 oi the positive and negative electrons on which they act, and 

 another set of forces acting equally and oppositely on the 

 positive and the negative. This latter set produces on the 

 body under consideration the same effect as would result 

 from a uniform electrostatic field, the body becoming elec- 

 trically polarized if of dielectric material, or, if a conductor, 

 acquiring a surface charge of electrification without internal 

 polarization. 



49. The state of things here suggested is somewhat dif- 

 ferent from anything ordinarily contemplated in electro- 

 statics ; the gravitational quasi-electromagnetic intensity 

 which acts throughout the substance of a conducting body 

 being balanced by the true electromotive intensity arising 

 from the surface distribution of electricity, so that we have 

 an electrostatic field of force exerted in a conducting medium 

 in equilibrium. In these circumstances, it may not be super- 

 fluous to point out that, in estimating the electric field-intensity 

 from the surface charges, no dielectric constant other than 

 that of free aether comes into play. For in an electrostatic 

 field, the intensity at any point is determined jointly by the 

 signs and positions of all the electrons concerned, and by 

 nothing else, each electron contributing to the field-intensity 

 the same component as if the other electrons were non- 

 existent. As is well understood, the electronic theory affords 

 on these lines an account of the dielectric qualities of different 



