366 PEINCIPAL HENRY A. MIEES AND MISS FLORENCE ISAAC ON THE 



and shaken continually while the enclosed crystals were watched with a lens. The 

 small crystals appeared to dissolve at first, their edges becoming more and more 

 rounded, until the water-bath fell to a certain temperature, after which the crystals 

 were seen to grow, their edges becoming quite sharp. This change is quite distinct, 

 and the temperature at which it occurs is taken as the temperature of saturation. 

 Thus each tube may give three temperatures of saturation at which crystals will 

 begin to grow, according as the enclosed crystals are a, /3, or y. 



Each experiment was repeated once or twice and with both rising and falling 

 temperatures. The mean of the values obtained was taken as the temperature of 

 saturation. 



The following results were obtained : 



1. Points on the a-solubility Curve. 



PICKERING gives six points on the a-solubility curve between the concentrations 

 80 per cent, and 100 per cent, of the acid, and the above points agree almost exactly 

 with his results. 



2. Points on the ft- solubility Curve. 



PICKERING also gives six points on the /3-solubility curve between the concen- 

 trations 80 per cent, and 100 per cent, of the acid, and here also the points obtained 

 above agree almost exactly with his results. 



