The Influence of Atmospheres of Nitrogen and Hydrogen on the Arc Spectra of Iron, Zinc, Magnesium, and Tin, Compared with the Influence of an Atmosphere of Ammonia

Abstract

It has been frequently assumed that chemical reactions in the electric arc have a considerable influence on the character of its radiations.* It seems not unreasonable to expect that the oxidation of the electrodes at high temperature in air would tend to increase the intensity over that obtained when the arc is operated in nitrogen alone. This presumed higher temperature might be sufficient to produce atomic vibrations entirely distinct from the vibrations at a lower temperature. If the atmosphere does have any such influence, the effect might be apparent in the spectrum of the arc. In the case of a hydrogen atmosphere t the most marked effects on the arc spectra of iron, zinc, magnesium, and tin have been found to be a general diminution of intensity and a change of relative intensity among the lines. The lines relatively enhanced by hydrogen are spark lines. Liveing and Dewar t have noted the effect of atmospheres of hydrogen and nitrogen on a number of lines in the magnesium arc and spark, and of these and other atmospheres on the cyanogen ? bands in the carbon arc, but as far as I am aware no extensive study has been made of the influence of nitrogen and ammonia on the arc spectrum of metals. From