Infra-red radiations of active nitrogen

The spectrum of active nitrogen in the visible and ultra-violet regions was first photographed by Lewis, with a small quartz spectrograph. Later, Fowler and Strutt made a more careful study of its spectrum by using instruments of greater dispersion and were able to prove definitely that most of the bands were identical with the first, second and third positive bands of nitrogen. They also observed for the first time in the spectrum of the discharge which produces the after glow, another group of bands about the region λ 2900 to λ 2200 which they called the fourth positive group. The present paper deals with an investigation of the spectrum of active nitrogen in the infra-red. Apparatus. The apparatus employed, shown in fig. 1, was very similar to that used by most of the investigators on this subject. The nitrogen is stored in a large bottle A, from which it is drawn through a bottle B of about 2 litres capacity filled with thin sticks of yellow phosphorus.