THERE is considerable difference of opinion regarding the possibility of the oxidation of nitrites by oxygen to nitrates. Berzelius reported that when aqueous solutions of alkali nitrites are boiled in air, they absorb oxygen with the formation of nitrates. G. Lunge and E. Fremy, J. Lang1 and others showed that aqueous solutions of nitrites pass into nitrates. According to R. Abegg and H. Pick2, oxygen of the air oxidises a solution of silver nitrite to silver nitrate. On the other hand, E. Divers3, Sir P. C. Rây4, C. Russworm5, M. Oswald6, and others observed no oxidation of solutions of nitrites in air. C. Matignon and G. Marchal7 reported that an aqueous solution of sodium nitrite is not oxidised by prolonged contact with oxygen, under a pressure of 50–55 atmospheres, even in the presence of a catalyst. But when the pressure is raised to 175 atmospheres and temperature to 395°–530°, solid sodium nitrite is almost completely oxidised to nitrate.