NOTES ON THE THEORY OF ELECTRONS 9 



This leads to interesting conceptions of Faraday's tension and 

 pressure along and perpendicular to the lines of polarization. Owing 

 to the motion of the electrons, the positive electron of one pair has 

 come nearer the next pair to the right than it originally was, and the 

 negative electron of the second pair has approached nearer the iirst 

 pair than it originally was. Hence there will be a greater attraction 

 between the two electrons than before ; in other words, there is an 

 increased tension between the two pairs of electrons. The same 

 will be true of the second pair of electrons and the pair next to the 

 right of it, etc. Hence there will be lines of tension between suc- 

 cessive pairs of electrons across from plate A to plate B, and hence a 

 force pulling the electrons in the two plates, and therefore the two 

 plates themselves together. 



It is easily seen, too, that in general there will be an increased 

 repulsive force between two pairs of electrons lying one above the 

 other, for if the positive electrons in each pair are pushed so as to 

 point in one direction, and the negative so as to point in the other, 

 the positive electron in one pair will in general be a little further 

 away from the negative in the other than before, and hence the 

 attraction between them will be diminished, which means, since they 

 were in equilibrium before, that there is now a resulting repulsion 

 between the two pairs. The same being true of all pairs lying one 

 above the other or one alongside of the other not in the line of polar- 

 ization, there is a resulting pressure perpendicular to that line of 

 polarization. 



Applying the law that the total electric current into a closed space 

 must equal that out of it, to the surface of plate A, we see that although 

 the plate is charged, the algebraic sum of the electron charges must 

 be the same as before. The same is true of plate B. In fact, 

 according to the above theory, we must mean by the charge on a 

 conductor simply the polarization or displacement of electrons in the 

 surrounding dielectric. The conductor is charged positively if the 

 positive electrons in the dielectric are displaced away from the con- 

 ductor and the negative toward it ; and, negatively, if the positive 

 electrons are displaced toward the plate and the negative away from 



