140 Proceedings of Indiana Academy of Science 



solution (1 vol.: 3 vol.)- For convenience in the laboratory these solu- 

 tions may be kept in bottles fitted with bulb tubes so marked that the 

 correct volumes may be withdrawn and added to the solution to be 

 tested. Shake gently. If cobalt is present the upper layer will have 

 a distinct blue-green color. If the color is not distinct carefully add 

 i;. few drops of 12N HCl to the ether layer. Presence of cobalt produces 

 the blue color. A colorless or straw-colored layer indicates its absence. 

 This test can be applied in most cases to the original solution if iron 

 is absent. 



When oxalates or phosphates are present, they may be removed 

 in the usual way by precipitating the iron, cobalt, and nickel as the 

 sulphides after remoAnng the manganese and treating the precipitate. 



Results. 



The following mixtures gave good, clear-cut tests for all of the 

 metals shown. The numbers represent milligrams of the atom named. 



Zn Cr Mn Fe Co Xi Al 



1 ~ 



2 



3 — 



4 — 



5 . . ■") 



6 5 



7 5 



8 5 



9 ."j 



11 .3 



12 .J 



13 5 



14 2 



l.-j 10 — 100 100 2 100 100 



A simplified scheme for the analysis of the Iron Group has been 

 worked out which takes less time and appears to give more consistent 

 results than the methods generally used. 



The troublesome reprecipitation of cobalt and nickel as the sulphides 

 and the careful adjustment of the reaction of the solution for the 

 dimethylglyoxime test for nickel have been eliminated. 



The Morrel-Vogel test for cobalt has been improved. 



A table showing the wide range of application of the scheme 

 described is given. 



The writer acknowledges indebtedness to his students, Donald Hoff- 

 man and Howard Dick for their aid with the experimental work, 

 and to Professor J. H. Reedy of the University of Illinois and Professor 

 J. F. G. Hicks of the University of Nevada for testing out the method 

 with their students. 



