ELISHA MITCHELL SCIENTIFIC SOCIETY. 17 



aluminum/ It was also put into use by him for short- 

 ening- the method of preparing- the pure zirconium 

 chlorides.- The reaction in question is that which 

 takes place when a nearly neutral solution of zirconium 

 chloride is boiled with sulphur dioxide in excess. 



Several points of interest were observed as to this 

 reaction. It was found that when a solution of the 

 sulphate was used it was difficult to secure any precip- 

 itation by means of sulphur dioxide even with persis- 

 tent boiling-. The chloride was clearly the best salt to 

 use. The pure chloride was made up into approxi- 

 mately a two and a half per cent, solution and this was 

 either very nearly neutralized by means of ammonia, or 

 ammonia was added until there was a slig-ht permanent 

 precipitate. In the latter case the saturation of this 

 solution with sulphur dioxide produced an immediate 

 precipitate. If this were permitted to stand for some 

 time the precipitate was redissolved, the remaining- 

 liquid being- only slig-htl}^ clouded. This re-solution 

 was probablv due to the hydrochloric acid liberated 

 and also to the excess of sulphurous acid present. If 

 this solution of zirconium chloride saturated with sul- 

 phur dioxide were diluted with several times its volume 

 of water and boiled from fifteen to thirt}^ minutes, a 

 heavy white precipitate was produced. This was quite 

 easily filtered b}^ means of an ung-lazed porcelain suc- 

 tion filter. The precipitate was washed several times 

 and finall}' dried over sulphuric acid in a desiccator. 

 The analysis g-ave: 



Zirconiuin dioxide. . . 61:10 61:75 61:75 .... 61,00 



Sulphur dioxide 22.24 22.20 



Ratio of zirconium to sulphur dioxide is 2 : 1. approximately. 

 Ratio of zirconium to sulphur dioxide in the neutral sulphite, 

 Zr (SOsJs, is 1 : 1.4. 



1. J. Am. C. Soc. 16. 475. 



2. This Jourxai.. U, 85. 



