52 



ATOMIC WEIGHTS OF SODIUM AND CHLORINE. 



Total silver = 9.38819 + 0.00011 = 9.38830 gm. This silver 

 contained 0.0037 P er cen ^ f impurity. Weight of pure silver present 

 9.38795. Then Ag : NaCl = 9-33795 = 5-08685 = 100.000 : 54.185. 



Molecular weight NaCl = 107.930 X 54- 185, if Ag = 107,930. 58.482 

 If atomic weight CI 35-455 



Atomic weight of sodium 23.027 



Ten such complete analyses are recorded in the table below. 

 The ratio of sodic chloride to silver. 

 FINAL SERIES. 



The agreement of these results is now as good as could reasonably 

 be expected. Whereas the earlier similar experiments, made before 

 time enough had been allowed for the full development of the opal- 

 escence, showed an extreme variation in the results of 0.017, this 

 extreme variation is now only 0.004. Since in these last experiments 

 seven different specimens of salt were used, and three different speci- 

 mens of silver, it seemed hardly probable that further work in the same 

 direction would add certainty to the average. The chemical identity 

 of the various preparations seems to have been proved. 



The atomic weight of sodium calculated from the ratio 100.000 : 

 54.185, the average of these ten determinations, is 23.027, if silver and 

 chlorine are respectively assumed to be 107.930 and 35.455. This 

 is 0.010 higher than the value obtained by reference to argentic 

 chloride a difference which seems small in comparison with much 

 quantitative chemical work, but which nevertheless is far greater than 

 the sum of the probable experimental errors of the two series of results. 



