208 



time dt, passes througli the dividing wall from [^J ^) into [öt J can be 

 again expressed in three ways. As b^ is constant, ds must also be 

 equal to the difference of the quantities of the substance S, which 

 enter and leave in the time dt [ij ; the same applies to [a^. 

 In this way we find : 



dl dl 



ds = KBAl {b,—a,) dt = BE- dt {b, — b,) = BD-dt (a„ — «J (9) 



dt dt 



If we put — =: in which tn represents the total period oi 



dt tn 



D V 



lixiviation of the mass and if we consider that — =z — ^x and that 



E X 



K.B.LI KO . ^. „ 

 we can write — tttttt- = — ^t toUows that 

 EBLl V 



KO n n 



— ih-a,) = {h-b,)-^-.v{a-a,)- . . . (10) 



V tf, t,i 



In the same manner may be deduced 2 (n — 1) other equations (10), 

 which relate to the other divisions. 



In an analogous manner as in the discontinuous lixiviation we 

 find from these equations: 



^=uJ^P^ I (//) 



b„ X — 1 



in which 



KO n 



V tn 



1 KO n 



P = +- 



X V tn 



This expression shows, therefore, a similarity to that of the dis- 

 continuous lixiviation. q and p, however, have a quite different 

 value. 



From the equations (10) may be again deduced by addition 



by which a^ is expressed in I\ and />„ (or U, respectively.) 



From the equations (10) may be deduced also a universal ex- 

 pression for the concentrations h. 

 This expression has the form : 



1) By [öi] is meant the division containing the concentration hi. 



