The spectrum of the hydrogen-nitrous oxide flame

The present investigation was undertaken on the suggestion of Mr. H. T. Tizard, F.R.S., arising out of some experiments in progress at the National Physical Laboratory. Previous observations of the spectrum of the hydrogennitrous oxide flame have not been very complete, and it was hoped that more extended observations, in connection with our present knowledge of the constitution of the molecules associated with certain band spectra, might throw further light on the process of combustion. Observations have accordingly been made over the range λ8225 to λ2250, with the result that the spectrum in question has been found to be identical with that of the flame of ammonia burning in oxygen, apart from differences in intensities of certain bands in the two spectra. The spectrum of the ammonia-oxygen flame has previously been described, but it may be useful to give an account of the experiments which have been made, and to state the modern interpretation of the spectra observed. As the results may be of interest to some who are not spectroscopists, it has been thought desirable to include a brief account of the spectra which form the basis of the conclusions reached.