Flint — Researches upon the Complexity of Tellurium. 211 



It may be noted that the mean atomic weight, 127*45, is prac- 

 tically identical with that found by N orris,* and that the 

 concordance of these experiments is quite as good as those 

 given by him. The close agreement of this result with both 

 the figure given by Norris and also those found by numerous 

 other investigators indicates a complete correspondence in 

 qiiality between the material employed in the present researcli 

 and that used by others. It also conliruis the general conclu- 

 sion that the atomic weight of tellurium, when prepared by 

 the ordinary methods, is 127"5. 



Tlie Fractionation by Water Hydrolysis, and Atomic Weights 

 of the Fractions Obtained. 



(See accompanying plan.) 



Five hundred grams more of the redistilled tellurium were 

 oxidized by nitric acid and converted to tetrachloride by 

 repeated evaporation with hydrochloric acid. The solution, 

 containing as little excess of acid as possible, was, in four 

 portions, diluted with about four liters each of boiling distilled 

 water and allowed to cool. The white, crystalline dioxide 

 which separated out was collected on a filter and washed. 

 After solution in hydrochloric acid (in slight excess) it was 

 reprecipitated by abundant dilution as before. When the fourth 

 repetition of this process had been made, using in each case 

 only the dioxide which had been previously precipitated by 

 dilution, a small portion of the fourth precipitate was taken 

 out as a sample. This was crystallized from nitric acid by 

 the usual method, and a second series of basic nitrate experi- 

 ments, conducted in every way like those of Table I, was 

 performed. The data of these are found in Table II. 



Table II. 



After Four F-actionations. 



Exp. STeOa.HNOs taken 2Te03 found Atomic weight 



grms. grms. of tellurium 



1 S-OYQIil 2-56876 126-53 



2 2-73622 2-28276 126-62 



3 2-36328 1-97153 126-57 



4 2-08497 1-73948 126-64 



10-26.378 9-5625.3 126-59 (Mean) 



The fractionation process was continued with the remainder 

 of the fourth precipitate in the same manner as before, and 

 the operations repeated without change until ten fractionations 

 * J. Am. Chem. Soc, xxviii, 1675. 



