ATOMIC AVEIGHTS 



419 



Mean, 69.9562, ± .0010 

 Hence Fe = 55.883. 

 The nine series of figures for this ratio comhinc tlins: 



Wackenroder 69.988, ± .0099 



Berzelius 70.020, it .0099 



Erdmann and Marchand 70.0094, ± .0080 



Svanberg and Noiiin, oxidation 69.9534, ± .0050 



Svanberg and Noiiin, reduction 70.0354, ± .0055 



Maumene 70.0008, ± .0019 



Rivot 69.33, ± .013 



Richards and Baxter, 1 69.961, ± .0047 



Richards and Baxter, 2 69.9562, ± .0010 



General mean 69.9728, ± .00083 



Although they are not in chronological order, the analyses of ferrous 

 bromide by Baxter ' may conveniently be considered here. He made two 

 sets of analyses, fixing the two usual ratios, by the established Harvard 

 methods. His figures, with all corrections and vacuum weights, follow : 



From Ag ratio, Fe = 55.836. 

 From AgBr ratio, Fe = 55.828. 

 And Ag: Br:: 100: 74.087. 



Dumas' ^ results, obtained from the chlorides of iron, are of so little 

 weight that they might safely be omitted from our present discussion. 

 For the sake of completeness, however, they must be included. 



Pure ferrous cliloride, ignited in a stream of hydrochloric acid gas, 

 was dissolved in water and titrated with a silver solution in tlie usual 



1 Proc. .'Vmer. Acad., 39, 245. 1903. 

 -Ann. Chem. Pharm., 113, 26. 1860. 



