ELISHA MITCHELL SCIENTIFIC SOCIETY. 25 



The method finally used was to fuse one gram of pow- 

 dered zircon with ten grams of sodium hydroxide in a 

 nickel crucible, the fusion continuing with an ordinary 

 burner for one-half hour, and then with a blast lamp for 

 twenty minutes. The contents were then poured upon a 

 piece of sheet nickel and cooled. During fusion the mass 

 was occasionally stirred with a nickel stirrer, which must 

 be thoroughly dry. The caustic alkali left on the rod 

 rapidly attracts water on cooling. The cooled mass on the 

 sheet nickel is transferred to a beaker of water and the 

 crucible is rinsed into the same. This was acidified with 

 hydrochloric acid, and in one case only was a residue left. 

 This hydrochloric acid solution was evaporated to dr}'ness 

 and the silica determined in the usual way. Treatment 

 with ammonium fluoride and weighing of the residue not 

 volatilized is essential, as a small amount of zirconia was 

 always found with the silica. 



For the iron the solution freed from silica was made up 

 to a known volume, definite portions withdrawn, and the 

 iron determined by titration with a potassium permanga- 

 nate solution. 



In determining the zirconia, measured portions of the 

 solutions were taken, rendered nearly alkaline with sodium 

 carbonate (this is best done in the cold solution); sodium 

 acetate was then added and the whole heated to boiling. 

 After boiling ten minutes the main part of the zirconia 

 will be found precipitated. This is filtered out. The 

 filtrate is acidified with acetic acid, again raised to boiling 

 and boiled for twenty-five minutes with sulphuretted hy- 

 drogen bubbling through. The nickel, coming from the 

 crucible, is thus precipitated and is filtered off. The filtrate 

 is acidified with hydrochloric acid and boiled until no fur- 

 ther smell of sulphur dioxide is noticed. Then precipi- 

 tate with ammonium hydroxide, wash thoroughly, dry and 

 ignite. From the weight of this last precipitate must be 



