Flint — Researches upon the Complexity of Telh^rium. 209 



Art. XXI. — Researches upon the Complexity of Tellurium', 

 by William R, Flint. 



[Contributions from the Kent Chemical Laboratory of Yale Univ. — ecxiv.] 



Introductory. 



In two papers"^ from this laboratory a description has been 

 given ot" a hydrolytic method for the fractionation of tellurium. 

 An account also has been given, in the second paper, of results 

 obtained from a preliminary application of the process in which 

 it was indicated not only that the substance might really be 

 complex in spite of the almost conclusively negative evidence 

 hitherto adduced, but also that its anomalous position in the 

 periodic system might be due to the actual presence, as 

 Mendeleeff predicted, of a constituent having a higher atomic 

 weight. 



In the work referred to, the fractionation was so conducted 

 as to produce both end fractions simultaneously, and since the 

 method employed was practically that of fractional crystalli- 

 zation, this involved, unless the operation had been long enough 

 continued, the introduction into each of these portions of 

 material from the middle fractions. 



It was therefore determined to modify the fractioning pro- 

 cess in such a way as to secure a more rapid separation of each 

 end fraction independently, and to apply it to a much larger 

 amount of material. 



Preparation of Material. 



About one kilogram of crude tellurium dioxide, extracted by 

 hydrochloric acid from electrolytic copper residues, supplied 

 by the Baltimore Copper Smelting and Rolling Co., was treated 

 by the same pui-ification pi'ocesses as those described in the 

 papers cited, the distillation and redistillation, in hydrogen, 

 being performed in this case in a silica tube, from porce- 

 lain boats. The tube' was very carefully cleaned between the 

 distillations, and, in redistilling, fresh boats were used. 



Plan of the Investigation. 



From the method of fractioning adopted, the investigation 

 naturally divides into two parts, in the first of which will be 

 described (1) determinations of the atomic weight of the 

 tellurium in unfractionated material ; and (2) the preparation 

 by hydrolysis with water of a series of fractions, together with 

 * Browning and Flint, this Journal, xxviii, 112 and 347. 



Am. Jour. Sci.— Fourth Series, Vol. XXX, No. 177. — September, 1910. 

 14 



