268 On the Measurement of Electric Resistance. 



the measures actually used, we get 

 EM'S 

 E'MS' ; 



hence using the absolute measure, 8=1. 



5. The fundamental law of voltaic induction represents the 



electromotive force e as an expression of the intensity i and of 



di 

 its change -5-, of the velocity of the inducing motion c, and of 



the distance r of the induced from the inducing element, and 



of several numbers which are given by the relations of the 



. • . ds els' 



lengths of the two elements to their distance — , — , and by the 



four angles e, 6, &, <£ which ds and c form with each other and 

 with r, and which ds 1 forms with r ; that is to say, if the con- 

 stant whose value is to be determined from the measures chosen 

 is called £, 



„r . ds ds 1 / 3 a a \ 1 di dsds 1 Q ~\ 



— Uci. — -—(cose— ~ cos a cos V' Jcos <p + ~ -rr 7— cos 6>cos<p 



The constant £ has the following significance : — If E and I are 

 the absolute units for electromotive forces and for intensities, and 

 C the absolute measure of velocity (a millimetre in a second), and 

 E', I', C the measures actually used, we have 



? E'lC ' 

 hence using the absolute measure itself, 



6. The general fundamental law of electric action represents 



the electric force F as an expression of the electric masses v, v\ 



ds 

 of their distance r, their relative velocity -j-, and their change 



ddr . . 



■jjg ; that is, if the constant whose value is to be determined 



from the given measures is called 77, we have 



* V 'rrl 1 aa\df ^ dtV J' 

 a stands for the number indicating the relation of that velocity 

 with which two electric masses must be moved against each 

 other in order that they exert no force on each other, to the 

 velocity of a millimetre in a second. 



The constant 7} has tbe following signification: — If F is the 

 absolute measure of force, N the absolute unit of electric fluid 

 (that mass of electric fluid which at a distance of a millimetre 



