204 THE ATOMIC WEIGHTS. 



with nitric acid, the chlorine was precipitated by a known 

 amount of silver. The figures in the third column show 

 the quantities of BiClj proportional to 100 jjarts of silver : 



Mean, 98.003, ± .090 



Hence Bi = 210.464, ± .294. 



The first three of the foregoing series of experiments were 

 made with slightly discolored material, and may therefore 

 be rejected. The remaining six percentages give a mean of 

 97.791 ; whence Bi = 209.78 ; or, if = 16, Bi = 210.26. 



As between the unaccordant results of Schneider and of 

 Dumas, those of the former chemist are i^robably nearest 

 correct. His method of determination was the more reliable, 

 and the details which he gives concerning his manipulations 

 afford strong presumptions of accuracy. Doubtless the bis- 

 muth trichloride used by Dumas, contained, like the corres- 

 ponding antimony compounds, traces of oxychloride. We 

 may fairly assume, for all practical purposes, that the atomic 

 weight of bismuth cannot be far from 208. 



TIN. 



Stannic oxide and stannic chloride are the compounds 

 which have been studied in estimating the atomic weight 

 of tin. 



The composition of stannic oxide has been fixed in two 

 ways; by synthesis from the metal, and by reduction in. 

 hydrogen. For the first method we may consider the work 

 of Berzelius, INIulder and Vlaanderen, and Dumas. 



