ELISKA :^:iTCHELL SCIENTIFIC SOCIETY. 51 



cipitation however was incomplete even in neutral solu- 

 tions. The text books vary in reg^ard to the properties 

 of this double sulphate ; sonie'^ state the precipitate to 

 be insoluble or sparing-ly soluble in either water or hy- 

 drochloric acid; another" states its solubility in water 

 alone and points out the danger of loss in the necessary 

 washing-. Rose' referring- to Berzelius*^ avoids this loss 

 by washing- with dilute ammonium or potassium hy- 

 droxide. These contradictory properties were all noted 

 in Watt's Dictionary. 



An experiment was carried out to learn the actual 

 deportment of this salt in the presence of water. A 

 fairl}^ concentrated solution of zirconium sulphate, con- 

 taining- ten per cent, of ZrO,, was completely neutral- 

 ized with ammonium hydroxide until a permanent pre- 

 cipitate was formed and this dissolved in two or three 

 drops of dilute sulphuric acid. This was done with a 

 boiling solution. To this was added an excess of a 

 saturated potassium sulphate solution. The beaker 

 was placed in cool water. When cold the supernatant 

 liquid, the flocculent precipitate having- settled well, was 

 decanted throug-h a tared filter. This filtrate, was 

 tested with more potassium sulphate, boiled and cooled, 

 but no further precipitation occurred. On addition 

 however of some ammonium h^^droxide a white precipi- 

 tate was thrown out, showing either that the potassium 

 sulphate did not precipitate the zirconium completely 

 or the precipitate was soluble in water. The precipi- 

 tate was washed several times b}' decantation and the 

 filtrate in each case showed the solubilitv of the salt. 



Roscoe and Schorl, vol. II, part II-p. 271., and Reg-nault Chimie 



11-285, and Wohler Handbiich Anorg-. Anal, p. 117. 

 Pelouse et Frem_Y Traite de Chimie Generale III-523 2nd Ed. 

 Anah't. Chem. translated by Griffin. 

 Pog-g-endorff's Annalen, IV. -136. 



