in the Motion of the Magnetic Field. 317 



^ l 2^ 1 + ^-e(/X 2 - y a 1 ) W 



Applying this formula to our case of magnetic induction 

 existing in a space amongst particles of matter absolutely 

 impermeable, we must take fi l to be equal to 1, and /ul 2 equal 

 to 0. The formula (6) will then take the following form : — 



/*=^> (7) 



which is identical with formula (5). It is easy to see from this 

 formula that the coefficient of magnetization k is equal to 



Tt +1 ) 



and I is connected to H by the formula 



£{J+l)l + H=0 (9) 



The magnetic energy of unit of volume is, as we know 

 from electromagnetism, expressed in terms of the magnetic 

 induction B and magnetic force H by the formula 



W=^-BH. 



By transforming this formula and using the relation (9) we 

 get 



W= ± BH = i- (H + 4ttI)H = ~H 2 + ijH 



07T 07T 07T A 



Here — H 2 is the energy of unit volume of magnetic field and 



07T ° 



the terms IH + — ( — f-ljl 2 represent the magnetic energy 



of the matter. These terms, also formulae (7), (8), and (9), are, 

 as we see, identical with those found before. Such a coinci- 

 dence in the results of the hypothesis of Magnetic Flux with 

 those of the hypothesis of Molecular Electric Currents permits 

 of our concluding that a system of spherical currents excited 

 without resistance on the surface of particles of matter is merely 



