414 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



the values 5.77 and 5.53 respectively. On account of the marked 

 difference between these values, new determinations of the density 

 were made by the displacement of toluol with weighed amounts of 

 salt. The toluol was first dried by stick soda and was then distilled. 

 Its specific gravity at 25° referred to water at 4° was found to be 

 0.86156. Great pains was taken to remove air from the chromate 

 when covered with toluol by placing the pycnometer in an exhausted 

 desiccator before setting. 



Balance and Weights. 



All weighings were made by substitution upon a nearly new short- 

 armed Troemner balance, easily sensitive to one fiftieth of a milligram 

 with a load of fifty grams. 



The gold-plated Sartorius weights were carefully standardized by the 

 method described by Richards, 31 and were used for no other work. 



SERIES I. 

 ! AgCl : Ag 2 Cr0 4 



0.752632 32 



Ag 



AgCl 



Discussion of Results. 



In comparing the analytical results, it is to be noted first that the 

 compositions of the different samples agree within less than one one 

 hundredth of one per cent, as the following averages show. 



31 Jour. Amer. Chem. Soc, 22, 144 (1900). 



32 Richards and Wells,. Pub. Car. Inst., No. 28 (1905). 



