50 JOURNAL OF THE 



Nos. 41 and 44 were carried out as iirst recommended 

 above. Nos. 33 and 34 were in the cold, the former 

 with one per cent., and the latter with three per cent, 

 of sodium thiosulphite. No. 36 had also three per cent., 

 but was boiled. No. 37 shows that a very small amount 

 of sodium thiosulphite will throw down most of the zir- 

 conium, as onl}^ live drops of a ten per cent, solution 

 were added in the experiment. The precipitation was 

 complete on addition of the thiosulphite up to two per 

 cent. (No. 38,) but the precipitate crept and only a 

 portion settled well. Nos. 39, 40 and 42 show the vary- 

 ing- interference of free hydrochloric acid, and No. 45 

 was a neutralized sulphate solution with twenty per 

 cent, of solid sodium thiosulphite. 



///. With Potatassiinn Sulphate. 



The very old method for separation, which Berzelius^ 

 used for want of a better, and one recommended for use 

 in a g-reat number of text books now, is the precipitation 

 of a zirconium sulphate solution as a basic zirconium po- 

 tassium sulphate, which according- to Paykull* may have 

 the formula, K,S04.2[2rO..Zr(S04)2] + 14Hp. "^ This 

 would be best broug-ht about by adding- an excess of a 

 saturated potassium sulphate solution to a neutralized 

 concentrated solution of zirconium sulphate. The pre- 



3. Pog-g-. Ann. III-208. 



4. Ber. VI-1467, and XII-1719. 



