52 ROYAL SOCIETY OF CANADA 



correction was very small, seldom amounting to as much as "2 of a 

 milligram. 



The amount of moisture still remaining in the dried pellet of 

 silver chloride was estimated in the manner followed by Stas, namely, 

 Ly heating the precipitate just to fusion in a tarred porcelain crucible, 

 the loss being then subtracted from the observed weight of silver 

 chloride. 



As stated above, the silver Which had been weighed out was slightly 

 in excess of the amount necessary to precipitate the chlorine in the 

 potassium chloride taken for analysis. This excess must be known 

 before one can determine the ratio of silver to potassium chloride. It 

 was estimated by adding to the filtrate a slight excess of hydrochloric 

 acid and washing and weighing the precipitated silver chloride with the 

 same care as attended the treatment of the main precipitate. In this 

 case a little hydrochloric acid in the washing water prevented any 

 appreciable amount of the silver chloride from dissolving. 



Before the observed weights of potassium chloride could be cor- 

 rected for the buoyancy of the atmosphere, it was necessary to know the 

 specific gravity of this salt. This constant has been measured 

 accurately by a number of experimenters; for the purpose cf this work 

 the number taken was 1 '995. The corresponding constant for the sil- 

 ver chloride was 5 •55. 



The balance used in this research had been specially procured for 

 atomic weight work. It was a long-armed Tromner balance, sensitive 

 to -03 milligram, with a load of forty grams. The beam and pans were 

 of aluminium, the rest of the metal being gold-plated. The weights were 

 carefully compared among themselves, according to the method sug- 

 gested by Eichards.^ 



Results of the Analysis of Potassium Chloride. 



The ratios obtained from the analysis of the potassium chloride 

 are given below. The atomic weights used in the calculations have the 

 same values as in the table above. 



» Jour. Am. Chem. Soc, 1901, 22, 144. 



