3:98 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 54 



K"orris,' in the course of an investigation which proved the unity of 

 telhirinm as an element, made a series of atomic weight determinations 

 by Koethner's metliod. The element itself was purified by various modes 

 of fractionation, and different fractions were found to be identical. The 

 basic nitrate was icnUiced by heating to TeOj, which was fused before 

 weighing; a precaution which eliminated the possibility of contamina- 

 tion bv enclosed erases. The uncorrected data are as follows: 



.0006 



A vacuum correction to the weights reduces this mean by 0.0074 to 

 83.5023. Hence Te = 127.48. Assuming the same correction to previous 

 series of determinations, the final value for the percentage of TeO^ is 

 given by the subjoined combination : 



Koethner, 1 83.480, ± .0014 



Koethner, 2 83.5003, m .0009 



Gutbier 83.432, ± .0156 



Norris 83.5023, ± .0006 



General mean 83.5000, ± .00047 



The investigation by Baker and Bennett " was also intended to de- 

 termine the definiteness of tellurium as an element. Different prepara- 

 tions from different sources were studied by several methods, and all 

 gave sensibly the same atomic weight. The results obtained by two 

 methods are given in detail, with vacuum weights throughout. First, 

 tellurium dioxide was heated with sulphur in tubes of glass, the two 

 ends of the tube being packed with silver leaf to avoid loss of tellurium. 

 Sulphur dioxide was expelled, and from its amount, as measured by the 

 loss in weight of the apparatus, the atomic weight of tellurium was com- 



'Journ. Amer. Chem. Soc, 28, 1675. 1906. 

 ='Journ. Chem. Soc, 91, 1849. 1907. 



