The reversal of the sodium line may be demonstrated without the use of a slit or a spectroscope. An incandescent lamp having either a carbon or tungsten filament is placed immediately behind a good sodium flame and viewed from a distance of fifteen or twenty inches through a diffraction grating. The first- and second- order spectra, right and left, will both be in view and in the orange-yellow region of each will appear a sharp dark-line image of the filament of the lamp. This image constitutes the dark-line spectrum of the sodium vapor.
Proceedings of the Iowa Academy of Science
©1926 Iowa Academy of Science, Inc.
Spinney, L. B.
"Notes on the Reversal of the Sodium Line,"
Proceedings of the Iowa Academy of Science, 33(1), 239-240.
Available at: https://scholarworks.uni.edu/pias/vol33/iss1/58