154 Dr. G. Bakker on the 



On the other hand we have : 



HS=(^— p T )v, 



and therefore : 



P*-P=j~<Pl-P*) (53) 



By means of the identity : 



Pl-P2\ * ) 



we find immediately : 



P-H**, .... (500 



P1-P2 Pi- P2 



which is the equation (50). 

 Now we have : 



vp*= J V/*«tt=S2:(l- 2l)^ + S^V- (54) 

 Further we found 



RCPi-pty-hZfr+tfPi-ips'z+pt'z, . (43) 



and R = Z(p»-pT)--H E {p s -p T -(p li >- pT >)}. (44) 

 From (54), (43), (44), and (37) we easily find : 

 *b-£v*.4k-W + f^(l-4) + f *(l+£), 



• . . (55) 

 or by substitution of p^ in (50) : 



H-(ft-fl) (r+ gy ( Pl - p , } ^^ . (5(i) 



Further we have: -JL^R^. So the equation (56) 

 becomes : P\ ~~P2 v y 



Pl - P2 + 4R' • ' • <- 57 => 

 ° r S(R,-R)=g + ^Vi_ l ,£l±l 2 . . (58) 



