244 THE ROYAL SOCIETY OF CANADA 



containing the above metals. Nitric acid, chlorine and more than 

 small amounts of sulphuric acid must be absent. The solution should 

 be cold lest ferric chloride be reduced by ether. All suspended matter 

 must be removed by filtration. 



A third method, known as Ford's method, depends upon the 

 conversion of the manganese present, in strong nitric acid solution, 

 to manganese dioxide by potassium chlorate. The dioxide is then 

 separated from the iron and other metals which remain in solution, 

 by means of an asbestos filtering medium. The manganese may now 

 be estimated either by a gravimetric or volumetric process. 



A rather interesting method for the separation of iron from 

 manganese is that suggested by R. B. Moore and Ivy Miller^ Ad- 

 vantage is here taken of the fact that, if pyridine is added in slight 

 excess to a solution of ferric chloride containing free hydrochloric 

 acid, the iron is completely precipitated, while the manganese remains 

 in solution. 



Anyone acquainted with these several methods appreciates the 

 fact that, with the exception of the last one, the processes involved 

 are long and tedious and that considerable experience is necessary 

 before reliable results can be obtained. A shorter and less trouble- 

 some method for the separation of iron from manganese is highly 

 desirable. 



Experimental Work 



The flasks, burettes and pipettes used in this work were cali- 

 brated on the basis of the true litre (U.S. Bureau of Standards). The 

 weights employed were compared the one with the other and all ex- 

 pressed as multiples of the 10 mg. weight, according to the suggestion 

 of Richards.^ 



The nitroso-phenylhydroxylamine ammonia was material sup- 

 plied for analytical work by Eimer and Amend. Samples were care- 

 fully tested for the presence of iron, aluminium and zinc. In the case 

 of two samples supplied the material had to be further purified before 

 using it in this work. 



A solution of ferric chloride, approximately 1/30 N, was prepared. 

 Sufficient hydrochloric acid was added to prevent an appreciable 

 hydrolysis of the iron salt. This solution was standardized gravi- 

 metrically, precipitating the iron with ammonium hydroxide and 

 weighing as ferric oxide. 



1 Journ. Am. Chem. Soc, 30, 593 (1908). 



2 Jour. Am. Chem. Soc, 22, 144 (1900). 



