44 THE ANALYSIS OF POTASSIC BROMIDE. 



SUMMARY. 



This investigation upon the atomic weight of potassium presents, among 

 other considerations, the following additions to the knowledge of the 

 subject: 



(1) The problem of preparing pure potassic bromide was solved in 

 two ways. 



(2) An unusually satisfactory method for preparing pure potassium 

 hydroxide was developed. This method is applicable to other alkalies, and 

 will be described elsewhere in greater detail. 



(3) The ratio of silver to potassic bromide was redetermined, and 

 found to be 100.000: 110.319. The atomic weight of potassium was thus 

 found to be 39.1143, if silver is 107.930 and bromine 79.953. 



(4) The ratio of argentic bromide to potassic bromide was found to be 

 100.000: 63.373. This determination yielded an essentially equal value, 

 K = 39.1135. 



(5) These values confirm in a striking manner the simultaneously 

 executed work upon potassic chloride, and unite with them in showing 

 that the atomic weight of potassium is 39.114. 



(6) By thus agreeing, these four values support the new value for the 

 atomic weight of chlorine in relation to silver and bromine. 



