408 



the expression 



Prof. E. Edlund on the Theory 



im 



M • n , l a 



: e = -j sm p cos yA As 



(6) 



for the force with which the magnetic pole tends to conduct 

 the electric fluid along the element of the circuit, i. e. for the 

 electromotive force of induction. 



In this expression e denotes the electromotive force, and i, 

 m, M, and p have the same meaning as before. If the phe- 

 nomena of unipolar induction can be explained by the aid of 

 this formula, that would show that there is reason to see in 

 them electrodynamic phenomena having no connexion with 

 the phenomena of induction strictly so-called. 



I shall show presently that formula (6) is identical with 

 the formula (5) deduced from the mechanical theory of heat. 



In fig. 3 let a C represent the element of the circuit in 

 which the induction takes place, b C the direction of motion 



Fig. 3. 



of this element, and C P the line of junction between the 

 magnetic pole and the element of the circuit. The lines A C 

 and B C are drawn at right angles to the line C P ; the first 

 in the plane passing through a C and C P, and the second in 

 the plane passing through b C and C P. Lastly, F C is the 

 normal to the plane b C P, and G C the normal to the plane 

 a C P. It follows from this that the lines G C, B C, A C, and 

 F C all lie in one plane, since each of them is perpendicular 

 to CP. But since the angles FOB and GCA are both 

 right angles, it follows that if we take away the angle A C B 

 the angles F C A and B C G are equal. 



According to formula (5), deduced from the mechanical 

 theory of heat, the element of the circuit aC = As ought to 

 be multiplied by sin (aCP), or, since the angle ACP is a 



