420 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 54 



wa}'. One hundred parts of silver are equivalent to the amounts of FeCl, 

 given in the third column: 



3.677 grm. FeCU = 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 grm. FeCl3 = 2.3475 grm. Ag. 50.224 



1.242 " 2.471 " 50.2G3 



Mean, 50.2435, ± .0132 



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



From FeCL Fe = 56.092 



From FeCls " = 56.231 



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.^ The data have, of course, slight 

 value, but may be considered as being in some measure confirmatory. 

 They are as follows : 



56.40 

 55.60 

 55.38 

 55.56 

 55.48 

 55.50 

 55.86 

 56.06 

 56.22 

 55.80 

 55.78 

 55.60 

 55.70 

 55.94 



Mean, 55.777, ± .0532 



These values undoubtedly depend on Eegnaulf s value for the weight 

 of hydrogen. Correcting by the later value, as found in the chapter of 

 this work relating to the density ratio H : 0, the mean becomes Fe = 

 55. 608, ±.0532, With = 16, Fe = 56.042. The probable error in the 

 weight of the hydrogen is ignored as having no practical significance. 



• Am. Chem. Journ., 10, 74. 



