Vol. X, No. 8.] Action of Nitric Oxide on Metallic Peroxides. 291 

 [N.S.] 



30-5°c and 765 mm, pressure (tension of aqueous vapour at 

 305c = 32*46 mm.). It will be seen, therefore, that the total 

 weight of nitrogen present = 003 gram, nearly. 



For the estimation of the weight of nitritic nitrogen pre- 

 sent the same method was employed as in the case of lead per- 

 oxide. Ten cubic centimetres of the solution of barium nitrite, 

 obtained as described above, were precipitated with sodium 

 sulphate and diluted to 50 cc. After oxidation with 25 cc. of 

 N/10 KMn 0^ (reduction factor 101) containing free alkali, 

 10 cc. of the diluted liquid were titrated with N/10 Na, S 8 . 

 Two experiments were made, the volumes of Na,, S 2 O solution 

 required being 2255 cc. and 22*6 cc. (mean 22-57 cc. respec- 

 tively). From these data it follows that the weight of nitritic 

 nitrogen present in 5 cc. of the original liquid = -0047 gram. 



It should be noticed that this is slightly greater than the 



total weight of nitrogen obtained by the nitrometic method, 



but considering the greater accuracy of the Rupp method, the 



agreement between the two results is, in our opinion, pretty 

 close. 



