RUTHENIUM. 311 



From (i i) Co = 58.870, ± .0094 



From (13) " = 58.920, ± .0327 



From (15) " ^ 59.072, ± .0075 



From (12) " = 59.349, ± .0108 



From (i) and (2) " = 59.562, ± .0382 



General mean, . . , Co = 58.487, =b .0013 



If = 16, this becomes Co == 58.932. 



Here again the oxide ratio, because of Zimmermann's work, receives 

 excessive and undue weight. The arithmetical mean of the fifteen values 

 is Co = 58.781. Between this and the weighted general mean the truth 

 probably lies, but the evidence is incomplete, and more determinations 

 are needed. 



RUTHENIUM. 



The atomic weight of this metal has been determined by Clans and 

 by Joly. Although Claus* employed several methods, we need only 

 consider his analyses of potassium rutheniochloride, K^RuClj. The salt 

 was dried by heating to 200° in chlorine gas, but even then retained a 

 trace of water. The percentage results of the analyses are as follows : 



Ru. 2KCI. Ck. 



28.96 40.80 30.24 



28.48 41.39 30.22 



28.91 41.08 30-04 



Mean, 28.78 41.09 30.17 



Reckoning directly from the percentages, we get the following dis- 

 cordant values for Ru : 



From percentage of metal Ru = 102.451 



From percentage of KCl " ^ 106.778 



From percentage of Clg " = 96.269 



These results are obviously of little importance, especially since the 

 best of them is not in accord with the position of ruthenium in the 

 periodic system. The work of Joly is more satisfactory.f Several com- 

 pounds of ruthenium were analyzed by reduction in a stream of hy- 

 drogen with the following results : 



* Journ. fi'ir Prakt. Chem., 34, 435. 1845. 

 t Conipt. Rend., loS, 946. 



