120 



the experiments, in tact iu-e considerabl}' larger ^). With such large 

 free paths there would be every reason to believe that the peculi- 

 arities of the movements of the electrons pointed out in § 4, which 

 are not consistent with Ohm's law, would begin to plaj a part 

 (which perhaps might resemble a PEi.TiEK-eftect such as seems to 

 reveal itself in the potential phenomena). It is, however, questionable 

 whether the whole hypothesis developed in § 4 in connection with 

 (Jomm. N° 119, concerning the movement of free electrons through 

 tl;e metal and which is also mentioned in § 10, must not be repla- 

 ced by an essentially different one for the super-conducting condition, 

 according to which the movement of the electrons is carried on by 

 the current for considerable distances, but each separate electron 

 which takes part in tiie progress, only moves one molecular distance. 

 To illustrate this idea we may take as an example the well 

 known case of the projiagation of a blow by a row of billiard 

 balls which just touch each other. In a super-conductor the flow 

 of electricity might consist in this, that an electron jumping across 

 onto an atom of the super-conductor from one side causes an 

 electron on the other side of the atom") to jump onto the next one, 

 etc. till finally -at the further end of the superconducting wire as 

 many electrons would be carried away in the direction of the 

 current, as were thrown in at the beginning ^). 



1) Taking the free path at ordinary temperature at 10—7 cm., it becomes 10^ 

 cm. at 2''.45 K., yet taking no account of the decrease of the number of free 

 electrons. We do not consider collisions of the electrons mutually, as these would 

 cause microresidual-resistance phenomena. 



2) To express it more accurately, in the same layer of atoms taken across the 

 path of the current, more passes over in a given time than is sent out (or thrown 

 l)ack) through the same layer in the same time to the side from which the elec- 

 trons taken up come. We here give only the simplest possible sketch, to charac- 

 terise the super-conducting condition. 



'■^) The taking up of an electron on one side of an atom and the giving off on 

 the oilier side of one to another atom, would then be accompanied by a moving 

 up of the electrons (through or) over the surface of the atom, by which each 

 electron moves along a part (if the number of electrons on the surface of an atom 

 is large, tlien a small part) of the diameter of the atom. The connection of the 

 electrons of two diiferent atoms with each other and with these atoms probably 

 docs not differ very much from the connection between the electrons of one atom 

 with each other and with the atom, so that the passing of an electron from the 

 one atom to the other in the superconducting state would be similar to the move- 

 ment of the electrons in a single atom. The conductivity of the super-conductor 

 would thus be that of the atoms united into one continuous whole (see § 4j. 



If the numerous electrons in the atom, which belong to the framework of it, in 

 the described process only pass on the blow from the one electron that jumps on 

 |0 the atom, onto the one that is given off without themselves taking part in the 



