TELLURIUM. 181 



2.000 grm. K2TeBrg gave 69.946 per cent. Br. 164.460 



6.668 " 69.8443 " 164.221 



2.934 " 69.9113 " 164.379 



3.697 " 70.0163 " 164.626 



1. 000 " 69.901 " 164.355 



Mean, 164.40S, ± .045 



From Berzelius' series we may calculate Te = 128.045, 

 and from v. Hauer's Te = 127.419. Dumas,* by a method 

 for which he gives absolutely no particulars, found Te = 129. 



In 1879, with direct reference to MendelejcfF's specula- 

 tions, the subject of the atomic weight of tellurium was 

 taken up by Wills.t The methods of both Berzelius and 

 von Hauer were employed, with various rigid precautions 

 in the way of testing balance and weights, and to ensure 

 purity of material. In the first series of experiments tellu- 

 rium was oxidized by nitric acid to form TeO,. The results 

 gave figures ranging from Te = 126.31 to 129.34 : 



2.21613 grm. Te gave 2 



1-45313 " I 



2.67093 " 3 



4.77828 " 5 



2.65029 " 3 



,77612 grm. TeOj. 79.828 per cent. Te. 



,81542 " S0.044 " 



,33838 " 80.007 



95748 " 80.207 



31331 " 79-989 



Mean, S0.015, ± .041 



In the second series tellurium was oxidized by aqua regia 

 to TeOa ; with results varying from Te = 127.77 to 128.00: 



2.85011 grm. Te gave 3.56158 grm. TeO.^. 80.024 per cent. Te. 



3.09673 " 3-86897 " 80.040 



5.09365 " 6.36612 " 80.012 " 



3.26604 " 4.08064 " 80.037 " 



Mean, 80.028, zh .004 



Combining these series with that due to Berzelius, we 

 have the following general mean : 



* Ann. d. Chim. et d. Phys., (3,) 55, 129. 1859. 

 IJourn. Chem. Society, Oct., 1879, P- 7*34- 



