THE ANALYSIS OF SILVER CHROMATE. 

 SPECIFIC GRAVITY OF SILVER CHROMATE. 



149 



In order to correct tte weight of silver chromate to a vacuum standard, a 

 knowledge of its specific gravity is necessary. This has already been deter- 

 mined by Playfair and Joule ^ and Schroeder,^ who obtained 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 were taken to remove air from the chromate 

 when covered with toluol by placing the pycnometer in an exhausted desiccator 

 before setting. 



The Specipic Gravity of Silver Chromate. 



The following vacuum corrections were applied: 



BALANCE AND WEIGHTS. 



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

 Troemner balance, easily sensitive to 0.02 mg. with a load of 50 gm. 



The gold-plated Sartorius weights were carefully standardized by the method 

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



* Mem. Chem. Soc, 2, 401 (1845). 



* Lieb. Ann., 173, 72 (1874). 



* Jour Amer Chem. Soc, 23, 744 (igco) 



