ATOMIC AVEIGHTS 



395 



Gutbier's^ determinations began with telluric acid, HgTeO,;. First, 

 the acid was dehydrated by heating in a stream of dry air, and the 

 water was collected in a calcium chloride tube and Aveighed : 



Mean, 23.550, dz .0083 

 Hence Te = 127.45. 



Secondly, telluric acid was reduced to tellurium by precipitation with 

 hydrazin hydrate. Gutbier's data are as follows : 



H.TeO, 

 .9380 

 .4963 



1.0485 

 .8865 

 .4339 

 .3492 



Mean, 55.507, ± .0165 



Hence Te = 127.31. Staudenmaier found 55.508,±.0068 per cent. 

 The general mean of both series is 55. 5079, ±.0067. 



Finally, tellurium dioxide was reduced to tellurium by the same 

 process : 



TeO.,. Te. 



.1662 .13287 



.3136 .2507 



.2799 .2238 



Per cent. Te. 

 79.946 

 79.942 

 79.957 



Mean, 79.948, ± .0031 



r9.948. 



Hence Te = 127.585. All of Gutbier's weights were reduced to a 

 vacuum standard. 



In a later memoir Gutbier ° gives two more series of reductions of tel- 

 lurium dioxide. In series I the oxide was reduced by hydrogen, and in 

 series II by hydrazin. Vacuum weights are given : 



Mean, 79.951, ± .0015 



Hence Te = 127.609. 



1 Liebig's Annalen, 320. 52. 1902. 

 ^ Liebig's Annalen, .342, 266. 190.5. 



