NITROGEN. 71 



The molecular weight of potassium nitrate is twice calculable, as 

 follows : 



From (7) KNO 3 = 100.405, .0026 



From (8) " 100.371, .0059 



General mean. . KNO 3 = 100.401, .0024 



Hence N = 13.947, .0057. 

 And for sodium nitrate we have : 



From (9) NaNO 3 = 84.430, .0026 



From (.10) " = 84.433, .0053 



General mean NaNO 3 = 84.431, .0023 



Hence N = 13.913, .0052. 



There are now seven estimates of the atomic weight of nitrogen, to be 

 combined by means of the usual formula. 



1. From NH 4 C1 N = 13.945, .0051 



2. " NH 4 Br " = 13.942, =h .0077 



3. " ratio (4) " = 13.935, .0073 



4- " " (n) " = 13.911, .0048 



5. " AgNO 3 "... " = 13.945,^.0044 



6. " KNO 3 " = 13.947, .0057 



7. " NaNO 3 " = 13.913, .0052 



General mean N = 13.935, .0021 



If oxygen is 16, this becomes 14.041. From Stas' data alone, Stas 

 finds 14.044 ; Ostwald, 14.0410 ; Van der Plaats, 14.0421 (A), and 14.0519 

 (B) ; and Thomsen, 14.0396. The new value, representing all available 

 data, falls between these limits of variation. 



