NICKEL AND COBALT. 295 



Several samples of each oxide were taken, yielding the following data. 

 The separate samples are indicated by lettering: 



NiO. 



2.0S20 

 2.0956 

 2.0148 

 2.2069 

 2.2843 

 2.1329 

 2.2783 



2.1434 

 2.4215 

 f 2. 1859 

 j 2.008S 

 I 2.0839 

 L 2.6560 



CoO. 



Nickel. 



Cobalt. 



Mean, 78.593, ± .0018 



( 2.12tl 

 I 2.0241 

 ^ 2.1226 

 I 1.9947 



L 3.0628 

 2. 1 1 67 



1. 7717 



1.7852 

 1.6878 

 2.2076 

 2.6851 

 2.1461 

 3.4038 

 2.2778 

 2.1837 



These percentages are practically identical, and lead to essentially the 

 same mean value for each atomic weight. 



In a later paper Russell* confirmed the foregoing results by a different 

 process. He dissolved metallic nickel and cobalt in hydrochloric acid 

 and measured the hydrogen evolved. Thus the ratio between the metal 

 and the ultimate standard was fixed without the intervention of any 

 other element. About two-tenths of a gramme of metal, or less, was 



* Journ. Chem. Soc. (2), 7, 494. 1867. 



