274 



THE ATOMIC WEIGHTS. 



Hence Te = 126.668, ± .0290. A reduction of the weighings to a 

 vacuum raises this by 0.07 to 126.738. 



Still another series of analyses, made with fractionated material, gave 

 values for tellurium running up to as high as 137. These experiments 

 led Brauner to believe that he had found in tellurium a higher homo- 

 logue of that element, a view which he has since abandoned.* Brauner 

 also made a series of anal3'ses of tellurium dibromide, but the results 

 were unsatisfactory. 



In the series of determinations by Gooch and Howlandf an alkaline 

 solution of tellurium dioxide was oxidized by means of standard solu- 

 tions of potassium permanganate. This was added in excess, the excess 

 being measured, after acidification with sulphuric acid, by back titration 

 with oxalic acid and permanganate. Two series are given, varying in 

 detail, but for present purposes they may be treated as one. The ratio 

 TeO., : : : 100 : x is given in the third column. 



10.017 

 10.026 

 10.097 

 10.149 

 10.055 

 10.122 



10055 

 1 0.000 

 10.143 

 10.022 

 10.033 

 10.098 



Mean, 10.068, d= .0100 



Hence Te = 125.96. 



In Staudenmaier's % determinations of the atomic weight of tellurium, 

 crystallized telluric acid, HgTeOg was the starting point. By careful 

 heating in a glass bulb this compound can be reduced to TeO,„ and l)y 

 heating in hydrogen, to metal. In the latter case finely divided silver was 

 added to prevent volatilization of tellurium. The telluric acid was frac- 

 tionally crystallized, but the different frOjCtions gave fairly constant results. 

 I therefore group Staudenmaier's data so as to bring them into series 

 more suitable for the present discussion. 



* Journ. Chem. Soc, 67, 549. 1895. 



t Amer. Journ. Sci., 58, 375. 1894. .Some misprints in the original publication have been kindly 

 corrected by Professor Gooch ; hence the differences between these data and the figures formerly 

 given. 



J Zeitsch. Anorg. Chem., 10, 189. 1895. 



