144 PHYSICS OF THE ELECTRON 



from the point of view of the mutual attractions which orientation 

 causes in the constitution of crystalline media, on account of the 

 complex electric and magnetic fields which surround a system of 

 electrons in its immediate vicinity. 



Gravitational forces alone remain distinct, superimposed on the 

 electromagnetic forces, and no difficulty comes from this on account 

 of the negative results of the experiments undertaken to show the 

 absolute motion of the earth. 



The negative results can be explained, as we shall see, if all the 

 internal forces of matter are of electromagnetic origin; but gravi- 

 tational force, alone different, can be superimposed on them without 

 introducing an appreciable modification of this result, for its in- 

 tensity is extraordinarily small compared to electromagnetic actions, 

 even if there is no mutual compensation between them, and in all 

 the experiments in question, interference of light or equilibrium of 

 an elastic system, the gravitational forces play no appreciable role. 



It would be, indeed, important to obtain a condition in a case of 

 equilibrium where the forces of gravity would play an important 

 part, and if the equilibrium remains independent of the total motion 

 to nearly the second order, if we could only observe the mutual 

 motion to this order of precision, it would be necessary to conclude 

 that the forces of gravitation also are modified by motion of trans- 

 lation in the same manner as the electromagnetic forces, since the 

 equilibrium between the two kinds of forces is not disturbed, and this 

 would be an important indication of the necessity of an electro- 

 magnetic representation of gravitation. We would be able, for 

 example, if the sensibility allowed it, to perform the experiment of 

 Trouton and Noble by suspending the condenser with a bifilar to 

 the pan of a balance instead of by an elastic fibre. 



Since this test has not been made, since experiments designed to 

 show the absolute motion have not involved weight, it would be 

 more reasonable to consider gravitation as a force distinct from 

 electromagnetic action, which acts at the interior of the electrons 

 in order to insure their stability, without its being possible actually to 

 imagine in what manner we can seek a more profound knowledge of 

 the ether and of the electrons which it incloses. 



It does not seem, in any manner and for many reasons, that this 

 can be of the nature of a material and mechanical representation of 

 the ether. 



VI. Cathode Rays 



(33) The Ratio e/m. Before examining the consequences involved in 

 the electronic conception of matter, I should like to examine a few 

 points relative to the electrons of two kinds. Those which we know 

 the better, the more intimately, are the negative electrons, which 



