Light of the Night Sky

I HAVE succeeded in exciting the auroral green line under conditions which indicate that it must have been produced in a manner similar to that in the light of the night sky. In order to describe my experiments properly, it is necessary first to recall the excitation of the green line in active nitrogen1. In that experiment it was possible for the first time to produce the green line under conditions which give some clue to its production in both the aurora and the night sky, since there are metastable nitrogen molecules in active nitrogen, and one would certainly expect metastable nitrogen to play an important role in the upper atmosphere. My recent discovery of a new modification of active nitrogen2, the afterglow of which was a very faithful reproduction of that part of the auroral spectrum which is due to nitrogen, added an argument for the hypothesis that the green line is excited by metastable nitrogen molecules.