178 HALL AND SMITH— COLUMBIUM. [May i 9j 



with a slight excess of ammonium hydroxide. The hydrate ob- 

 tained in this way was dissolved in dilute hydrochloric acid, and 

 an excess of ammonium carbonate, together with ammonium sul- 

 phide, added to its solution. The iron separated in the form of 

 sulphide and with it there was a small amount of titanium. The 

 filtrate from this precipitate was boiled with hydrochloric acid and 

 ammonium hydroxide added. The hydrate which was precipitated 

 was ignited and tested as to its photographic power. It gave a 

 picture after an exposure of five days. It contained uranium. It 

 showed the greenish color characteristic of U 3 8 . After this it was 

 fused with acid potassium sulphate, taken up in water and the solu- 

 tion boiled. A precipitate formed on cooling but disappeared on 

 warming, thus indicating the presence of members of the cerium 

 group or of zirconium. On the addition of ammonium hydrate 

 there separated a hydrate which, after filtration and washing, dis- 

 solved completely in a solution of oxalic acid. This pointed to 

 the presence of zirconium. The hydrates were again precipitated, 

 dissolved in sulphuric acid, and the solution neutralized with 

 potassium carbonate and saturated in the cold with potassium sul- 

 phate. By this precipitation the zirconium was obtained in the form 

 of insoluble double sulphate, while the uranium remained in solu- 

 tion. After filtering out the zirconium potassium sulphate it was 

 dissolved in hydrochloric acid and zirconium hydrate precipitated 

 with ammonium hydroxide. It was well washed with water and 

 dissolved in hydrofluoric acid. An equivalent amount of potassium 

 carbonate was added and, on evaporation, potassium zirconium 

 fluoride crystallized out. Three grams of this salt were obtained. 

 Analysis. — 0.5043 gram of the salt ignited with sulphuric acid 

 gave 0.5272 gram of K 2 S0 4 + Zr0 2 , and contained 0.2212 gram 

 of Zr0 2 , leaving 0.3060 gram of K,S0 4 . 



Calculated 

 K 2 ZrF 6 . Found. 



2KF 4I05 40.47 



ZrF 4 58-95 59-52 



100.00 99-99 



The uranium in the filtrate from the zirconium was precipitated 

 with ammonium hydroxide, dissolved in hydrochloric acid, and an 

 excess of sodium hydroxide added to this to obtain the glucinum. 

 This was not found. The uranium was changed to nitrate and the 



