ELISHA MITCHELL SCIENTIFIC SOCIETY. 11 



of washing; especially as somewhat similar experiments 

 were carried out under the next headino-. 



VI. THE SOLUTION OF ZIRCONIUM HYDDOXIDE IN CAUS- 

 TIC ALKALI. 



It was found that zirconium hydroxide was percepti- 

 bly soluble in solutions of potassium and sodium hydrox- 

 ide. Experiments were first made with a view of deter- 

 mining" the extent of this solubility. Solutions of the tw^o 

 alkalies were made up of different streng-ths, an excess 

 of zirconium hydroxide added, and the solution then boil- 

 ed. After coolino-, a measured (quantity of the solution 

 was drawn off and the amount of zirconia present deter- 

 mined. 



A 50 per cent solution potassium hydroxide dissolved per cc 0.00233 gm. 

 33 " " " " " " " " 0.00097 " 



25 " " " " ■ '• " " " 0.00075 " 



12 '• '• " " " " '' " 0.00009 " 



In the case of sodium hydroxide there seemed to be a 

 strongfer solvent action. 



A 33 per cent solution dissolves per ec. 0.00245 »,n'am. 

 25 " " " '' " " 0.0012 



12 " '' '• •' " " 0.0005 



If a concentrated solution of alkali, saturated with zir- 

 conium hydroxide, is diluted, a portion of the zirconium 

 will be precipitated. Neutralization with acid will also 

 cause a precipitation of the zirconium. In both cases 

 alkali is retained by the precipitate in spite of washing-. 

 Analyses were made of some of these precipitates after 

 very thoroug-h washing- (in no case was less than a liter 

 of water used.) The results in four experiments w^ere 

 suilicient to show that these precipitates were practically 

 zirconium hydroxides with a varying- pcrcentag-e of alka- 

 li, this percentag-e ranging- from 1.15 to 3.04. It is pos- 

 sible to assume that zirconates were formed and then de- 

 composed by the action of water during- the washing-, 

 but it seems more probable that this is, as is true in the 



