SELENIUM. 



179 



62.93 

 62.95 

 62.97 

 62.94 

 62.98 

 62.98 

 62.95 



Mean, 62.957, dz .005 



Second. A warm aqueous solution of selenious acid was 

 mixed with HCl, and reduced by a current of SOo- The 

 reduced Se was collected upon a glass filter, dried, and 

 weighed. Percentages of Se in SeO; : 



199 

 185 

 193 

 187 

 191 



Mean, 71. 191, dr .0016 



This series, combined with that of Sacc, 71.088, dz .032, 

 gives a general mean of 71.1907, ± .0016. 



There are now five series of figures from which to deduce 

 the atomic weig-ht of selenium : 



) Per cent, of .Se in Se02, 71.1907, dz .0016 



) BaSe03 : BaS04 : : 100 : 88.437, == -013 



) Per cent, of Hg in HgSe, 71.7327, ^z .003 



) Se : SeCl^ : : 100 : 178.696, n: .125 



) Per cent, of Ag in AgjSeO,, 62.957, re .005 



From these we get the following values for selenium 



From (i) Se = 78.894, ± .018 



(2)- 

 (3)- 

 (4)- 

 (5)- 



= 78.362, dz .053 



78.700, 



79-174, 

 78.819, 



.019 

 .064 

 .025 



General mean. 



If = 16, Se = 78.978. 



78.797, zt: .Oil 



