ALLEGAN METEORITE AND MART IRON 49 



The portion ^, therefore, contains 17.48 percent stony matter, 

 but a comparison of the ratio of SiO^ and MgO shows that this 

 has not the same composition as that of the main siHcate por- 

 tion. While 50 percent of the Latter is soluble in hydrochloric 

 acid, the former contains 39 percent soluble and 61 percent 

 insoluble material, which may be due in part, at least, to the 

 more magnetic properties of the enstatite. It is, therefore, er- 

 roneous to assume that the silicate accompanying the metal has 

 the same composition as the main portion. The above data 

 give the means of calculating approximately the amount of 

 FeO in the magnetic portion, while the troilite is found from a 

 sulphur determination. The relatively greater amount of 

 chromite in the magnetic portion is also noteworthy. 



For the separation of iron from nickel and cobalt, the am- 

 monium sulphocyanate method of Zimmermann^ was used 

 with satisfactory results. It is necessary to add a little more 

 sodium carbonate than is sufficient just to destroy the red color 

 of the ferric sulphocyanate and to heat to boiling, but even then 

 the precipitation of the iron is not absolutely complete, a small 

 portion always remaining in solution and being removed by am- 

 monia after destroying the sulphocyanate by nitric acid, and 

 concentrating. The bulk of the iron is free from nickel and 

 cobalt after one repetition of the precipitation. Like all other 

 methods for separating iron from nickel and cobalt, this is ap- 

 proximative, but it avoids the tedious repetition of the acetate 

 method and the precipitates filter well. 



The separation into a soluble and an insoluble portion was 

 effected by repeated treatments with hot dilute hydrochloric 

 acid and alternate digestion with caustic soda. The insoluble 

 portion, after ignition, was 49.96 percent, and the analysis of 

 this and of the solution gave : 



'Ann. Chem. (Liebig), 199: 10. 



