AEPINUS ATOMIZED. 



851 



much calculation it is easy to see that generally the excess of the elec- 

 tro-inductive permeability aboyé unity will be much greater than 

 three times the su m of the volumes of the electric atoms per unit 

 yolume of space, which we found in § 24 for the electro-inductive 

 permeability of an assemblage of single atoms, sparse enough to produce 

 no disturbance by mutual actions. Also without much calculation, it is 

 easy to see that now the induced electric moment will not be in simple 

 proportion to F, the intensity of the electric field, as it was rigourously 

 for a single atom through the whole range up to the disruptional value 

 of F; but will tend to increase more than in simple proportion to the 

 value of F; though for small practical values of F the law of simple 

 proportion is still very nearly fulfilled. 



§ 29. Raise the température now to anything under that at which 

 the solid would melt. This sets the electrions to performing wildly 

 irregular vibrations and rotations, so that some of them will occasion- 

 ally be shot out of their atoms. Each electrion thus shot out will 

 quickly either fall back into the atom from which it has been ejected, 

 or will find its way into another atom. If the body be in an electric 

 field F, a considérable proportion of the electrions which are shot out 

 will find their way into other atoms in the direction in which they are 

 pulled by F; that is *to say, the body which was an infinitely perfect 

 insulator at zéro absolute température has now some degree of electric 

 conductivity, which is greater the higher the température. There can 

 be no doubt that this is a matter-of-fact explanation of the electric 

 conductivity, which so nearly perfect an insulator as the flint glass of 

 my quadrant electrometer at atmospheric températures shows, when 

 heated to far below its melting point (according to Prof. T. Guay, j ) 

 •98.10" 24 at 60° Cent.; 4*9. 10" 24 at 100°; 8300. 10" 24 at 200° Cent ); 

 and of the enormous increase of electric conductivity of rare earths at 

 rising températures above 800° C, so adrairably taken advantage of 

 by Prof essor Nernst in his now celebrated electric lamp. 



§ 30. If the hypothèses suggested in the présent communication are 

 true, the electric conductivity of metals must be explained in the same 

 way as that of glass, gutta-percha, vulcanite, Nernst filament, etc., 



l ) Proc. Roy. Soc. Jan. 12. 1882. 



54* 



