Arc spectra in vacuo and spark spectra in helium various elements

Abstract

The rapid progress in recent years in the investigation of arcing voltages and resonance potentials in metallic vapours and in their relation to certain spectral series, which for many elements lie in the extreme ultraviolet region of the spectrum, makes it of great importance to obtain as extensive and as accurate as possible a knowledge of the ultra-violet spectra of the elements. A stimulus has been given to this work by the recent research of Foote, Roguley, and Mohler, on the ionisation potential of thallium vapour, and by that of Mohler, Foote, and Stinson, on the ionisation potential of lead vapour. The series indicated by their values lie almost entirely in the Schumann region, which can be studied only, with the fluorite spectrograph or the vacuum grating spectrograph. The present work is a continuation of that already carried out by McLennan, Ainslie, and Fuller on the vacuum arc spectra of various metals, and includes a study of the vacuum arc spectra of antimony, bismuth, calcium, magnesium, selenium, copper, and silver, and the spark in helium spectra of aluminium, antimony, bismuth, cadmium, calcium, lead, magnesium, thallium, and tin. The study of these spectra has been successful in that certain additions to our knowledge of the spectra of these elements has been made in every case.