( 173 ) 



If we begin with llie inelling-|)oiiil line of Na.^SO^ . 10 H^O, we 

 observe that the qnanlily Vsf, which stands iicre instead of y.s/ , is 



/ X 3 ^ S" 6 J 8 ^:^ 



Fig. 1. 

 negative, whereas ?/y and Vf^i are positive, and as WsfVgi'^ irrjiVsf, 

 the numerator of equation (3) is positive. 



In the denominator % — xi is negative, but in spite of this the 

 denominator is positive because of the great value of Vfji . 



n ' 



Numerator and denominator are positive, and I „' ) is positive 



in the stable region, so that i is positive. 



dt 



Proceedings Royal Acad. Amsterdam. Vol. XIV. 



12 



