LUEDEKING — THE HYDRATION OF COLLOIDS. 



3S1 



For the coefficients of change « = '^'(90 -'^2o)'^2o we have from 

 the above table the followino- values : 



A comparison of the values for zinc vitriol solution in water 

 with those of Beetz* shows a good concordance, as will be seen 

 from the following table : 



10 p. cl Zn.So, + 7H,o. GalvaDlc CondnctlTity x lO^ 



30° 

 40° 

 50° 

 60° 

 70° 



Found, 

 2916 

 3471 

 3964 



437^ 



47SS 



5077 



Calculated. 

 243S 



3492 

 4056 

 4610 

 5164 

 5718 



We see that at higher temperatures just as Beetz found the con- 

 ductivity increases less than corresponds to the formula — 



Z= ^32.09 + 4.0364;^ -o.0473/2-)io9. 



The tigures representing the dependence of the galvanic conduc- 

 tivity upon the temperature show, that at the point of change of 

 the liquid gelatin into the solid state, even for very concentrated 

 solutions, there is no sudden change. 



The coefficients of change show that the change of conductivity 

 with temperature is greater in proportion as the concentration of 

 the gelatin solution is greater. But the influence of the addition 

 of gelatin changes with the concentration of the zinc vitriol. 



The first result is contrary to that obtained by Arrhenius, that 

 the coefficients of change are independent of the concentration of 

 gelatin. The reason of this contradictory result is to be found in 

 the fact that Arrhenius used only very dilute gelatin solutions. 



Beetz, Wiedemann's Galvanismus, 1. p. 328. 



