ELISHA MiTCHEIvL SCIENTIFIC SOCIETY. 47 



No:3. 20-26 inclusive were made 'from the chloride 

 solution aud Nos. 27-28 with the sulphate. No. 20 was 

 carried out in the cold with a large excess of ammo- 

 nium hydroxide. The solution was diluted to about 

 150 c.c. and the precipitate washed w^th cold water. 

 No. 21 was also cold, the precipitate being- obtained 

 b}^ ammonium h^^droxide (sp. gr. 0.97) drop at a time. 

 On addition of the fourth drop the precipitation was com- 

 plete. No. 22 had also only a slight excess of amnao- 

 nium hydroxide, but the zirconium was precipitated 

 hot. No. 23 shows the necessity for boiling off the 

 excess of ammonium hydroxide. It was precipitated 

 from a hot solution b}^ a large excess of ammonium h}^- 

 droxide (10 c.c. sp. gr. 0.97j. Nos. 24- and 25 

 respectively contained a slight aud large excess of am- 

 monia, but the boiling was continued for fifteen min- 

 utes in each case. No. 26 was diluted to about 100 c.c. 

 (the others were diluted to about 150 c.c.) and 20 c.c. 

 of concentrated ammonia water (sp. gr. 0.92) added 

 and that boiled for fifteen minutes. No. 27 was car- 

 ried out hot, the slight excess of ammonium h3^droxlde 

 added being boiled until there was only a faint odor of 

 it left. No. 29 was precipitated by adding 50 c.c. con- 

 centrated ammonia water (sp. gr. 0.92). The w^hole 

 solution in this case amounted to about 100 c.c. This 

 w-as boiled twenty minutes. Most of the ammonia had 

 disappeared. 



Since zirconium is frequently precipitated in a chlor- 

 ide solution w^hen the alkaline chlorides are also present, 

 it seemed advisable to note the effect ' the presence of 

 these substances had on the determination by means of 

 ammonium hydroxide. Experiments were therefore 

 made with the zirconium chloride dissolved in ten per 

 cent, solutions of ammonium, sodium, and potassium 



