1901.] on the Existence of Bodies Smaller than Atoms. 581 



the sphere of action of one of the particles on a corpuscle does not 

 extend as far as the nearest particle. We shall show later on, that 

 the sphere of action of a particle on a corpuscle depends upon the 

 velocity of the corpuscle — the smaller the velocity the greater being 

 the sphere of action — and that, if the velocity of the corpuscle falls as 

 low as 10 7 centimetres per second, then, from what we know of the 

 charge on the corpuscle and the size of molecules, the sphere of action 

 of the particle might be expected to extend further than the distance 

 between two particles ; and thus, for corpuscles moving with this and 

 smaller velocities, we should not expect the density law to hold. 



Existence of Free Corpuscles or Negative Electricity in Metals. 



In the cases hitherto described the negatively electrified corpuscles 

 had been obtained by processes which require the bodies from which 

 the corpuscles are liberated to be subjected to somewhat exceptional 

 treatment. Thus, in the case of the cathode rays the corpuscles were 

 obtained by means of intense electric fields : in the case of the incan- 

 descent wire by great heat, in the case of the cold metal surface by 

 exposing this surface to light. The question arises whether there is 

 not to some extent, even in matter in the ordinary state and free from 

 the action of such agencies, a spontaneous liberation of those cor- 

 puscles — a kind of dissociation of the neutral molecules of the sub- 

 stance into positively and negatively electrified parts, of which the 

 latter are the negatively electrified corpuscles. 



Let us consider the consequences of some such effect occurring in 

 a metal, the atoms of the metal splitting up into negatively electrified 

 corpuscles and positively electrified atoms, and these again after a time 

 re-combining to form a neutral system. "When things have got into a 

 steady state, the number of corpuscles re-combining in a given time 

 will be equal to the number liberated in the same time. There will 

 thus be diffused through the metal swarms of these corpuscles : these 

 will be moving about in all directions like the molecules of a gas, and, 

 as they can gain or lose energy by colliding with the molecule of the 

 metal, we should expect by the kinetic theory of gases that they will 

 acquire such an average velocity that the mean kinetic energy of a 

 corpuscle moving about in the metal is equal to that possessed by a 

 molecule of a gas at the temperature of the metal ; this would make 

 the average value of the corpuscles at 0° C. about 10 7 centimetres per 

 second. This swarm of negatively electrified corpuscles when exposed 

 to an electric force will be sent drifting along in the direction opposite 

 to the force ; this drifting of the corpuscles will be an electric current, 

 so that we could in this way explain the electrical conductivity of 

 metals. 



The amount of electricity carried across unit area under a given 

 electric force will depend upon and increase with (1) the number 

 of free corpuscles per unit volume of the metal ; (2) the freedom with 

 which these can move under the force between the atoms of the 



