IRON. 289 



Two more results, obtained by Rivot* through the reduction of ferric 

 oxide in hydrogen, remain to be noticed. The percentages are : 



69.31 

 69-35 



Mean, 69.33, .013 



We have thus before us six series of results, which we may now com- 

 bine : 



Berzelius 70.020, .0013 



Erdmann and Marchand 70.0094, =b .0080 



Svanberg and Norlin, oxidation 69.9534, .0050 



Svanberg and Norlin, reduction 70.0354, .0055 



Maumene 70.0008, .0019 



Rivot 69.33, - OI 3 



General mean 70.0075, .0010 



From this we get Fe = 55.596. 



Dumas' f 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 chloride, ignited in a stream of hydrochloric acid gas, 

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

 way. One hundred parts of silver are equivalent to the amounts of Fed, 

 given in the third column : 



3.677 grm. FeCl. 2 = 6.238 grm. Ag. 58.945 



3.924 " =6.675 " 58.787 



Mean, 58.866, .053 



Ferric chloride, titrated in the same way, gave these results : 



1.179 g rm - FeCl 3 = 2.3475 grm. Ag. 50.224 



1.242 " =2.471 " 5- 26 3 



Mean, 60.2435, .0132 



These give us two additional values for Fe, as follows : 



From FeC! 2 Fe = 55.742 



From FeCl s " = 55.907 



A series of determinations of the equivalent of iron, made by students 

 by measuring the hydrogen evolved when the metal is dissolved in an 

 acid, was published by Torrey in 1888. J The data have, of course, slight 



* Ann. Chem. Pharm., 78, 214. 1851. 

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

 I Am. Chem. Journ., 10, 74. 



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