Flint — Researches upon the Complexity of Tellurium. 217 



is likewise practically identical with the mean, 126'58, of Table 

 II, in the previous part. Whetlier tliis fact indicates that a 

 more rapid fractionation can be secured by the hydrolysis of 

 the niti-ate than by tliat of the chloride, remains for further 

 investigation to prove. 



Atomic weight determinations of the more soluble fraction 

 have not as yet been made. 



Investigation of the Fraction less easily Hydrolyzed by Water. 

 (See accompanying plan.) 



The tellurium in the filtrates from the water hydrolysis 

 described in the preceding part was recovered by treatment 

 with ammonia and acetic acid. The dioxide thus secured was 

 next dissolved in hydrochloric acid and the solution was diluted 

 abundantly with boiling water and allowed to cool. The 

 filtrate from the dioxide thus precipitated was again heated to 

 boiling, and ammonia and acetic acid were added, in the usual 

 way, to complete precipitation as dioxide of the remaining 

 tellurium. Tins latter portion was re-treated in the same man- 

 ner, and the process repeated twice more, each time using 

 only the ammonia-acetic acid precipitate from the preceding 

 operation. 



As the result of these four fractionations, almost exactly 500 

 grams of dioxide were obtained by the water precipitation, 

 while the unhydrolyzed fraction secured by ammonia and acetic 

 acid consisted of scarcely more than ten grams. From the 

 fifth repetition, on the ten gram portion, a very small quantity 

 of crystalline, pure white dioxide was obtained by dilution and 

 cooling of the hydrochloric acid solution. The filtrate was 

 heated to boiling and sufficient ammonia added to neutralize 

 part of the acid, whereupon an orange-colored, crystalline 

 deposit, similar to that obtained in the nitric acid fractionation 

 above described, began to form. Boiling for ten or fifteen 

 minutes threw out about eight grams of this product, which 

 was separated by decantation of the liquid, washed, and dried. 



After filtering the liquid and reheating it to boiling, more 

 anuTionia was added, but still not enough to neutralize all the 

 acid present. By this means another crystalline deposit was 

 secured, yellow in color, and only a gram or so in quantity. 

 When the filtrate from the last mentioned substance was again 

 heated and finally precipitated completely by ammonia and 

 acetic acid, a minute amount of floccy precipitate appeared. 

 Nothing preeipitable by stannous chloride in either acid or 

 alkaline solution was found in the last filtrate, and it was there- 

 fore rejected. Tlie floccy precipitate was collected on a filter, 

 washed, and dried. Its amoxmt was too small to admit of its 



