Fitzgerald — On a Model illustrating Properties of Ether. 411 



wheels must turn simultaneously. This rotation of the wheels 

 represents the magnetic force, and the motion of the parts of the 

 wheels in contact with the circuit being everywhere in the same 

 direction round it, represents the electric current. There is no 

 transference of anything along the current, and the energy de- 

 veloped at any point is transferred to that point, not along the 

 current, but in at its side in the direction of the elastic bands per- 

 pendicular to the current. Now, this is exactly the state of affairs 

 that Professor Poynting showed to exist in an electric current. 

 This direction is at right angles to the axis of rotation of the 

 wheels, and also to the direction of polarisation of the bands, i. e. 

 to the magnetic and electric displacements. The self-induction of 

 this circuit is represented by the momentum of the wheels. It is 

 easy to see how the polarisation of the bands is connected with the 

 resistance along any length of the circuit. When the. resistance is 

 great the bands will be greatly polarised, i. e. the electric displace- 

 ment is great, i. e. the rate of fall of potential will be great ; and 

 as this will be directly proportional to the resistance, we see that 

 the fall of potential along any length of the circuit is proportional 

 to the resistance of that section, which is Ohm's Law. In order 

 completely to represent Ohm's Law, it would be necessary to 

 arrange that the friction was proportional to the rate of revolution 

 of the wheels. This, however, is trenching on the connexion of 

 matter and ether. Another question, similarly circumstanced, is 

 the mechanical force exerted on the conductor, due to a mag- 

 netic field. It is evident that the direction in which to look 

 for a mechanism to represent this would be something depending 

 on the centrifugal force of the rotating wheels; but I have not 

 invented any satisfactory way of representing it. The mutual 

 induction of currents may be exhibited by making two circuits, on 

 one of which the current is forced, and on the other of which the 

 bands are simply loose. Now, on starting the first circuit, the wheels 

 outside the second all rotate the same way, which I have explained 

 represents an electric current in it ; and the wheels inside will 

 stay unmoved until the friction of the loose bands gradually sets 

 them in motion, and thus, after a little while, the wheels all 

 over the region are rotating just like those anywhere else, i. e. 

 those at opposite sides of the circuit are rotating in the same 

 direction, and the current has ceased in the circuit. The oppo- 



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