402 Mr. E. T. Glazobrook on the Molecular 



tromagnetic action may be explained by the hypothesis that 

 the conducting medium is filled with a viscous fluid of con- 

 stant density ; forces X, Y, Z being applied to this medium at 

 any point, rotational motion is set up. 



The electromotive force parallel to the axis of x at any point, 

 so far as it depends on external electrification, is 



2\ pdi) 9 



p being the pressure in the fluid, and fi the magnetic specific 

 inductive capacity. The magnetic force in the same direction 

 is <»!, the angular velocity of the fluid about the axis of x. 

 The electromotive force arising from electromagnetic action is 



2dt 2 ' 

 f being the displacement of a particle of the fluid. By the 

 action of these electromotive forces currents may be produced 

 at any point, and the current at a point parallel to Ox is 



3tt V U/ 



If h is the viscosity of the medium and its electrical con- 

 ductivity, then 



1 4:7T[aJc 



Now let C become very small ; then k becomes very large, 

 the medium ceases to be a viscous fluid and becomes an elastic 

 solid. Equations (1), (2), (3), (4), (5) hold ; but instead of 

 (6) we have 



/l=^ A K14M)-^.. • (id 



But, integrating (4 a), 



Assuming that /is zero everywhere initially, 



Let 



2 \ p dx\dx dy dz) J " dx 9 



* All these expressions are of course simplified if, with Maxwell, we 

 put |= p> 



