46 JOURNAIv OF THE 



The strength of each was determined by evaporating* 

 to dryness, ig-niting' the residue and weig-hing- the ZrOg 

 obtained. Amounts taken for the experiments were 

 measured from these solutions by means of a calibrated 

 standard burette with a small outlet. 



THE deter:.iination oe zirconium. 



/. Expcriniods ijitli Amynouiurn Hydroxide. 



Ammonium hydroxide precipitated the zirconium com- 

 pletely from a cold solution in either a small or larg-e 

 excess. If the solution be hot, however, the excess of 

 ammonium hydroxide must be boiled off, /. c, the pre- 

 cautions taken when aluminium hydroxide is precipi- 

 tated must be heeded. The precipitate is white and 

 flocculent, settles quickly, is easily filtered and washed 

 with hot w^ater. In most of the experiments carried 

 out this precipitate was washed until the wash water 

 g-ave no further precipitate, or only a sligfht cloudiness, 

 with silver nitrate. The precipitate was ignited and 

 heated over the blast lamp until there was no further 

 loss of weig'ht, the residue weig^hed being- taken as 

 pure zirconium dioxide. 



The following- results were obtained: 



