74 PHYSICS OF MATTER 



markable degree of agreement in the estimates by various physicists 

 of the size of these ultimate particles, meaning by that the smallest 

 distance between their centres as they rebound from each other, 

 especially when it is considered that these results have been reached 

 from so many different points of view, and are based on such a variety 

 of physical data. 



As to the structure of the atom itself a most remarkable theory 

 has been recently developed. J. J. Thomson has marshaled the evi- 

 dence in favor of the theory proposed by Larmor that matter has an 

 electrical basis, and the theory has already been considerably devel- 

 oped by Lorentz and others. There appears to be reason for believing 

 that the corpuscles of the Kathode rays are simply moving charges 

 of negative electricity, their whole apparent mass being due to their 

 relation to the ether, in consequence of which there is a magnetic 

 field around the moving charge having energy dependent on the 

 square of its velocity. The corpuscle, therefore, effectively has mass 

 in consequence of this reaction between it and the ether. 



The corpuscles are found always to carry the same charge, what- 

 ever the nature of the gas in which the Kathode rays are formed, and 

 whatever the nature of the electrodes the charge being the same 

 as that given up by the hydrogen atom in electrolysis, while the mass 

 of the corpuscle is about one one-thousandth that of the hydrogen 

 atom. 



The energy in the ether associated with the moving corpuscle 

 depends on the size of the corpuscle as well as upon its charge, and 

 it is found that to account for its apparent mass it must be of ex- 

 tremely small size relative to ordinary atomic dimensions. 



Professor Thomson suggests that the primordial element of matter 

 is such a negative electron combined with an equal positive charge, 

 the latter being of nearly atomic dimension. An atom of hydrogen 

 may be thought of as made up of nearly a thousand such pairs, the 

 positive charge being distributed throughout a spherical region 

 giving rise to a field of force within it in which the force on a nega- 

 tive corpuscle will be towards the centre and proportional to its 

 distance from the centre. In this field of force the corpuscles are 

 conceived as describing closed orbits with great velocities. 



The internal energy of such an atom is conceived as enormous. 

 In case of the atoms contained in a gram of hydrogen Thomson 

 reckons about 10 19 ergs as the energy received from mutual attrac- 

 tions in the formation of the atoms, an amount of work that would 

 lift a hundred million kilograms, one thousand meters. 



The whole mass of the atom is supposed to be due to the negative 

 electrons or corpuscles which it contains. As to the positive charge, 

 although it determines the apparent size of the atom, it appears to 

 make no contribution to its mass. 



