10 UNIVERSITY OF COLORADO STUDIES 



it. This view is very similar to Maxwell's idea of the charge on a 

 conductor. Maxwell, however, apparently considered electricity as a 

 single incompressible fluid, that could be displaced either in one 

 direction or the other at any single point, but not in both directions 

 at once, whereas, according to the present point of view the electrons 

 do not fill space entirely, and the positive electrons may be displaced 

 m the opposite direction to the negative. 



The mechanical force pulling the two plates (Fig. 2) together 

 is not due to an excess of positive electrons in plate A attracting an 

 excess of negative electrons in plate B, but for the most part to the 

 displacement of electrons along the lines of polarization, and the conse- 

 quent system of pressures and tensions. "We cannot, however, do 

 away with the ether on this hypothesis, for the ether is necessary in 

 order to explain the attractions and repulsions of neighboring elec- 

 trons, unless, of course, we postulate direct action at a distance be- 

 tween them. It is interesting to note, that if we accept the usually 

 quoted values for the number of molecules in a cubic cm. of gas, 

 and, the charge on an electron, the average extreme displacement of 

 an electron before a spark passes through the gas is, roughly estimated, 



— 1 



3x10 cm. if we assume there are two electrons in each molecule. 

 This displacement is g-^th of the average distance between the 

 molecules. 



Granting the hypothesis that a current of electricity is due to 

 the motions of charged electrons, it follows that "Weber's molecular 

 currents must be nothing more nor less than the revolution of the 

 two or more electrons in a molecule. If the positive and negative 

 electrons had the same mass they would move with the same velocity 

 around paths of the same size, and the magnetic effect of one would 

 practically annul that of the other, since they must revolve in the same 

 direction and a negative charge traveling in one direction means a 

 current in the opposite direction. J. J, Thompson, however, has 

 shown that the negative electron is about one thousand times smaller 

 than the rest of the atom or molecule. Hence the negative electron 

 will revolve with greater velocity around a larger circuit than the 



