162 Journal of the Mitchell Society [March 



has been treated with hydrochloric acid, then caustic soda, and lastly 

 leached with acidulated water. This would only partially remove 

 the iron present. 



The use of zirconia as a cloudino- agent for glass 



GLASS . • 



has been mentioned above. A thorough compari- 

 son with stannic oxide in this application apparently has not been 

 worked out. 



The addition of a small amount of zirconia to vitreosil or silica 

 glass is said to increase the tensile strength and resistance to bending 

 or breaking, and to diminish the tendency to devitrification. The 

 temperature at which the ware softens is practically unchanged. The 

 appearance is not improved. 



Zirconium salts, as the hvdrated sulphate or the 



TEXTILE ' "^ . . . 



INDUSTRY acetate, have been used as a weighting filler for silk. 



The weight may be increased up to 50 per cent. 

 Stannic salts are ordinarily employed for this purpose. 



Various zirconium compounds are also used as mordants in dyeing 

 and in the preparation of lac dyes. Zircon white is used as a pig- 

 ment, having good covering powers and being unaffected by chemical 

 agents. A patent has also been issued for the preparation of a zir- 

 conyl tannate. 



The colloidal properties of the hvdroxide have 



COLLOIDAL , ' . 



HYDROXIDE bceii Compared with those of other hydroxides and 



its use suggested in the purification of water. Also 

 it may find a use as a substitute for sodium tungstate or stannate in 

 rendering cloth non-inflammable. 



As "Kontrastin" it may be substituted for bis- 



MEDICINAL . , "^ 



muthyl nitrate as a lining substance for the stom- 

 ach, etc., in X-ray observations and radiographs. It has the ad- 

 vantage of being non-poisonous. 



The carbide has been recommended as a polish- 



ABRASIVE , . ^ 



ing agent, abrasive, and for glass cutting. 

 CHLORINATING Willgcrodt has suggested the use of the tetra- 



^GENT chloride as a chlorinating agent. 



Chapel Hill, N. C. 



