ELISHA MITCHELL SCIENTIFIC SOCIETY. 67 



He proceeded"'"' by adding- an excess of h^'droofen diox- 

 ide to a moderately acid solution of a mixture of iron, 

 zirconium and titanium. After twenty-four hours 

 standing- in a stoppered flask, the precipitated oxide 

 (Zr^Os) was caug-ht and Altered, washed and ig-nited. 

 In carrying- out this method the writer noted the neces- 

 sity of having an acid, yet not too acid, solution. If 

 the solution was first neutralized with ammonium hy- 

 droxide or sodium carbonate, the precipitated zirconium 

 oxide was higfhl}' contaminated with iron, which could 

 not be washed out. 



Analyses ofave these results: 



The precipitation was found to be complete on boiling- 

 the solution two or three minutes to avoid the twent\'- 

 four hours delay b}^ standing- cold. After filtering- from 

 the zirconium oxide, the filtrate was rendered alkaline 

 with ammonia water, filtered and the precipitate dis- 

 solved in dilute hydrochloric acid. The excess of acid 

 was neutralized and the titanium determined b^^ precip- 

 itation on boiling- with sulphur dioxide.'" The iron was 

 determined from the filtrate from this. 



The hydrog-en dioxide obtained from the manufac- 

 turer^^ was found to contain a large amount of silicic 

 acid in solution along with the other ordinary impuri- 



29. Ibid p. 482. 



30. The author J. Am. Ch. S. 



31. Dr. Merchand, 28 Prince st., New York. 



