4 ART. 15. M. OGAWA : PRELIMINARY 



greenish black precipitate with ammonium sulphide, insoluble in 

 an excess of the reagent, and a yellowish brown precipitate with 

 potassium Chromate, insoluble in acetic acid and quite different in 

 appearance from that of lead Chromate. Potassium iodide gives 

 no precipitate. 



The yield of the oxide was a few contigrams from one 

 kilogram of the mineral. The portion of the mineral soluble 

 in nitric acid also yielded a small quantity of the oxide. 



I had also in store all the ammonia precipitate separated from 

 the crude hydrogen sulphide precipitate given by Sir William 

 E.AMSAY. The whole of this precipitate was ignited and treated 

 as if it had been the original mineral, and a little over one 

 decigram of the oxide was obtained from this source. 



Salts. Several attempts have been made to get well crystal- 

 lised salts, but thus far without success. After fusing the oxide 

 with hydrogen potassium sulphate, dissolving the fused mass in 

 water, precipitating the hydroxide by ammonia, dissolving the 

 precipitate in different acids, and evaporating these solutions, 

 very soluble imperfect crystals were, indeed, obtained ; but these 

 crystals change to basic insoluble compounds on treatment with 

 water. Attempts to get well defined crystals of double salts, 

 containing the element in question, also ended in failure. 



Anhydrous chloride. The oxide was heated in a porcelain 

 boat in a current of chlorine gas, saturated with the vapour of 

 carbon tetrachloride. There was formed a very slight white 

 sublimate, the main portion of the product remaining in the boat 

 as a white powder having a slightly yellow tinge. On continued 

 heating at low redness, a pale green sublimate was formed; but 

 it was very slow in formation and insignificant in amount. 



The residue in the boat, doubtless consisting of the anhydrous 



