RICHARDS AND BONNET. — DISSOLVED CHROMIC SULPHATE. 11 



o.7° r 



o.c c 



0.5 C 



0.4° 



o.: 



0.2 C 



or 



10 



20 



30 



40 



60 



00 



Figure 1. — The Results of Catalysis. 



Hours are plotted abscissally, and changes in the freezing point ordinately. 

 The curve A corresponds to pure acid, B to freshly boiled green solution, // to 

 freshly made violet solution, and E to both of these solutions after having been 

 kept for a month at 30°. 



color of the solution, which at the end of five days had become decidedly 



green. 



This series of experiments thus showed the following facts : — 



First, the green salt hydrolyzed at 50° contained slightly less acid 



than that hydrolyzed at 100°, the respective acidities being perhaps 0.10 



and 0.13 normal in a \ molar solution. 



