Aluminum from Iron. 417 



the objective point is the preparation of the pure salt of 

 aluminum, is obviously incompatible with the attainment of 

 quantitative accuracy in the retention of the aluminum. We 

 have found, however, that various mixtures of anhydrous ether 

 and the strongest hydrochloric acid can be used satisfactorily 

 as solvents for the iron chloride, while the aluminum chloride 

 is insoluble to a very high degree in a mixture of hydrochloric 

 acid and ether taken in equal parts and thoroughly saturated 

 with gaseous hydrochloric acid at the atmospheric temperature. 

 We found that 50 cm^ of the solution of aluminum chloride, 

 obtained by mixing about 0*1 grm. of the hydrous chloride 

 (dissolved in 2 cm^ of water) with the mixture of pure^ 

 specially prepared aqueous hydrochloric acid and ether in equal 

 parts and again saturating the liquid at 15° C. with gaseous 

 hydrochloric acid, left upon evaporation and ignition 0*0004 

 grm. in each of two experiments — results which indicate a 

 maximum solubility corresponding to 1 part of the oxide or 

 approximately 5 parts of the chloride in 125,000 parts of the 

 equal mixture of ether and aqueous hydrochloric acid of full 

 strength. 



Pure aqueous hydrochloric acid of full strength mixes per- 

 fectly with its own volume of anhydrous ether, but it is a 

 curious fact that the addition to this mixture of any very con- 

 siderable amounts of a solution of ferric chloride in strong 

 hydrochloric acid determines the separation of a greenish oily 

 etherial solution of the ferric salt upon the surface of the acid. 

 The addition of more aqueous acid does not change the condi- 

 tions essentially, but more ether renders the acid and the oily 

 solution completely miscible. The ferric chloride seems to 

 abstract ether from the ether-acid mixture and, then dissolved 

 in the ether, remains to some extent immiscible with the aque- 

 ous acid thus left until the addition of more ether restores to 

 the mixture that which was taken from it by the ferric chloride. 

 Our experiments show that, while for the separation of in- 

 soluble aluminum chloride from certain small amounts of solu 

 ble ferric chloride the mixture of the strongest aqueous hydro- 

 chloric acid and ether in equal parts serves a most excellent 

 purpose, when larger amounts of ferric chloride are to be dis- 

 solved ether must be added proportionately in order to prevent 

 the separation of the ethereal solution of ferric chloride from 

 the rest of the liquid. 



Grreat care was taken to insure the purity of the aluminum 

 chloride used in the test experiments. The so-called pure 

 chloride of commerce was dissolved in the least possible amount 

 of water and this solution was treated with a large volume of 

 strong hydrochloric acid. The chloride thus obtained, free 

 from iron, but possibly contaminated (as we found by expe- 



