THE presence of atomic nitrogen1,2 in auroras is now proved beyond doubt by the identifications of the forbidden lines λ 3466 (2P → 4S) and λ 5200-5198 (2D → 4S). No specific processes for the dissociation of the nitrogen molecules or for the excitation of the nitrogen atoms appear to have been yet suggested. It is the purpose of this communication to show that dissociative recombination of N2+(X′) ions, as shown in reaction (1), can, at the same time, cause dissociation of nitrogen molecules and excitation of the resulting nitrogen atoms to the required metastable states. © 1951 Nature Publishing Group.