Prof. Norton on Molecular Physics. 279 



movement of electric aether throughout the entire route of the 

 current. Now the rapidly moving molecules of electric aether 

 must act impulsively against the universal aether in their path ; 

 and every such impulse must be propagated indefinitely outward 

 through this aether. The innumerable impulses thus originating 

 in a current are parallel to the direction of the current, and 

 must take effect upon all surrounding molecules in this direction. 



They constitute what may be called the external impulsive force 

 of the current. The well-known phenomena under immediate 

 consideration, as well as all the other phenomena of the external 

 action of currents to be discussed, are to be ascribed to the ope- 

 ration of this external impulsive force. Let us first take the case 

 of two parallel wires conveying currents in the same direction. 

 The impulses propagated from these wires will tend to weaken 

 the tension of the universal aether lying between the wires. A 

 similar effect, but less in amount, will be produced upon the 

 aether lying on the outer sides of the wires. The aethereal tension 

 should therefore be in excess upon the outer sides of the wires, 

 and hence they should be urged toward each other, or there 

 should be an apparent attraction between the wires conveying 

 the currents. The excess of aethereal tension here alluded to is 

 attributable to the fact that the impulses proceeding from the 

 one wire, in being propagated through the other, are materially 

 reduced in intensity. This effect results mainly from the disper- 

 sion produced by the interstitial aether, which is brought into a 

 very disturbed state of density by the swiftly moving atoms of 

 the electric aether in the current. When only one of the wires 

 conveys a current, no attraction or repulsion is observed, because 

 the dispersion just mentioned is wanting. 



If the currents be supposed to traverse the wires in opposite 

 directions, then the same operative cause, the external impulsive 

 forces of the currents, will compress the aether between the wires 

 to a greater degree than beyond them, and thus there will be an 

 effective force urging them further apart. 



Let a, fig. 8, be a point of one of the currents from which an 

 impulse is propagated, and ab, ac, ad Fi? 8 



lines radiating from it and crossing the 

 second wire, v, under different degrees 

 of obliquity. The dotted lines drawn 

 between bd and eg represent the lines 

 of moving electrical atoms. Each of 

 the lines ab, ac, ad will cross the same u 

 number of such lines, and therefore impulses propagated along 

 them will encounter the same number of moving atoms, and expe- 

 rience the same proportional diminution. This diminution should 

 be a certain constant fractional part of the impulse that reaches 



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