596 SCIENCE PROGRESS 



theory that the movements of the bound electrons do not give 

 rise to any current energy. An analogy can be found in the 

 movements of a long row of equally heavy billiard balls. Here, 

 as is well known, if all the balls are touching in a long row, on 

 striking another ball smartly against one end the ball at the 

 far end is thrown off without any movement of the intervening 

 balls. Hence the super-conductive state may be conceived as 

 one in which the atoms are so closely bound that the movement 

 of an electron from one to the other is of the same nature as 

 the movements of the bound electrons in the atoms. Hence 

 the effect of any disturbing influence, such as high current 

 density, magnetic field, etc. This causes the vibrators between 

 the atoms to separate them so that the electrons cannot pass 

 from one to another without doing work, with the result that 

 an Ohmic resistance is developed. 



