312 R. Sissingh on Kerr's 



tities from the theory of metallic reflexion*. The remaining 

 quantities are determined by the equations : — 



5, m sin (r + go) 

 tan o 1 = zr— -, — - — . , 



X 1 + 77? COS (t + G>) 7 



~ msin(T + &)) 



tan o 2 = — =— - -, — - — r, 



— 1 + ??i cos (t + CO) 



tan 8, 



m sin (t + co) 



tan 2 a + m cos (t + co) ' 

 pj = 1 + ??2 2 + 2m cos (t -f- co), 

 p^= tan 4 a + m 2 + 2 tan 2 a . ??i cos (t + a>) , 



°7? * 

 COS a 



From these formulae fi and m have been calculated for 

 different angles of incidence. The theoretical value of the 



amplitude contains the factor — „- e, 7iN, in which N is the 



magnetic force, T the time of oscillation of the electrical 

 wave-motion (the incident light- wave), e x is the constant of 

 dielectric polarization of air, and h is the magnitude of the 

 Hall transverse electromotive force. This latter is equal to 

 JiN times the component of the electric current by which it is 

 produced, in consequence of the magnetic force N. On 

 account of the unknown quantity e 1? this factor, which in the 

 remainder of the paper we shall call A, cannot be calculated. 

 Therefore, instead of the theoretical amplitudes, only numbers 

 proportional to them have been calculated. In the following 

 Table only the means of /-t. and fi ti m i and m t are given, since 

 we have already shown (§ 16) that these quantities are equal 

 to each other within the limits of error. 



* Cf. § 19. _ 



t A discussion of the theoretical considerations will give the signs of 

 the quantities involved in these formulae and the quadrants to which r, 

 o, and the various S's belong. Cf. Verhandel. Acad. Amsterdam, Deel 

 xxviii. (1890). 



