66 ATOMIC WEIQUT DETERMINATIONS. 



H. Capitaine : 51.36 (0 = 16) ; 321 (0 = 100). 



Determined by the peroxidation of galvanically reduced 

 iron and by measuring the hydrogen evolved on the solution 

 of iron in sulphuric acid. {Annal. de Chim. et de Phys., (3,) 

 ^, 1841, 126.) 



H. Wackenroder : 5548 (0 = 16). ' 



Wackenroder helped Stromeyer in his reduction of ferric 

 oxide, of which he gives the details. He also describes five 

 experiments of his own, which gave the oxygen contents of 

 ferric oxide at from 30.01 to 30.38. He took no precautions 

 to purify his hydrogen and thinks that the loss of oxygen 

 may have been apparently reduced. [30.195 oxygen cor- 

 responds to the above value for Fe.] [Berzelius' Jahresbe- 

 richt, U, 1844, 121 ; Arcliw. der Pharm., 36, 1844, 22.) 



Svanberg and Norlin: 55.97 (0 = 16); 349.805 

 (0 = 100). 



In seven experiments a known weight of iron was dis- 

 solved in nitric acid and the salt decomposed by heat. The 

 operation was performed in a glass flask. The mean re- 

 sult in vacuo, was 349.104; extreme difference, 0.803. In 

 seven experiments ferric oxide was reduced with purified 

 hydrogen. The mean was Fe = 350.514 ; extreme differ- 

 ence, 0.735. The number .taken is the mean of all the ex- 

 periments, m vacuo. Berzelius in his Lehrbuch cites the 

 experiments and, by neglecting the reduction to vacuum, 

 gets a slightly different number. He also expresses a pre- 

 ference for the experiments by reduction. [Berzelius^ Jah- 

 resbericht, ^i, 1844, 121 ; and Poggend. Ann., 62, 1844, 270.) 



J. J. Berzelius : 56.05 (0 = 16) ; 350.32 (0 = 100). 



Berzelius, as a check on the last determination, made two 

 experiments on the oxidation of iron by nitric acid with 

 special precautions against partial reduction. The number 

 is the mean ; difference, 0.101. The iron was melted down 

 with glass and magnetic oxide. In his Lehrbuch he adopts 

 the mean of these experiments and Svanberg and ISTorlin's 

 reduction determinations. [Poggend. Ann., 62, 1844, 270.) 



Erdmann and March and : 56.016 (0 = 16); 350.1 

 (0 = 100). 



Erdmann and Marchand made eight experiments on the 

 reduction of ferric oxide in a carefully purified current of 



