TIN. 



203 



We now have, for tin, the following available ratios : 



(l.) Sn : SnOj : : loo : 127.076, =b .0026 



(2.) 4Ag : SnCl^ : : 100 : 60.207, =b .0060 



(3.) Percentage of tin in SnBr^, 27.123, ± .0020 



(4.) Percentage of tin in K.jSnCl5, 29.040, =b .0021. 



(5.) Percentage of tin in AnijSnClg, 32.369, ± .0088 



(6.) Sn : 2BaS0^ : : loO : 392.056, ± .0713 



The antecedent values are — 



O = 15.879, zb .0003 K = 38.817,^.0051 



Ag = 107.108, ± .0031 N = 13.935, ± .0021 



CI = 35.179,^.0048 S = 31.828, =b .0015 



Br =: 79.344, zb .0062 Ba =; 136.392, i .0086 



With these, six independent values for Sn are computable, as follows 



From (i) Sn = 117. 292, ±.0115 



From (2) . 

 From (3) . 

 From (4) . 

 From (5). 

 From (6) . 



= 117.230, ± .0331 

 = 118.120, db .0131 

 = I18.152, zb.0155 

 = 1 18. 190, d= .0382 

 ^ 1 18.216, ± .0220 



General mean Sn = 1 17.805, ± .0069 



If = 16. Sn.= 118.701. 



If we reject the first two of these values, which include all of the older 

 work, and take only the last four, which represent the concordant results 

 of Bongartz and Classen, the general mean becomes — 



Sn ^ 1 1 8. 1 50, zb .0089 



Or, with O := 16, Sn = 119.050. This mean I regard as having higher 

 probability than the other. 



A single determination of the atomic weight of tin, made by Schmidt,* 

 ought not to be overlooked, although it was onh^ incidental to his research 

 upon tin sulphide. In one experiment, 0.5248 grm. Sn gave 0.6659 SnO.^. 

 Hence, with = 16, Sn = 118.49. This lies about midway between the 

 two sets of values already computed. 



* Berichte, 27, 2743. 1894. 



