IX. The effect of pressure upon arc spectra.—No. 2. Copper, λ 4000 to λ 4600

Abstract

The effect of pressure upon the arc spectrum of copper was first investigated by Humphreys and Mohler, who, in 1897, found that under pressure up to 14½ atomspheres the lines became broader and were displaced towards the less refrangible end of the spectrum. In 1907 photographs were obtained by Humphreys at pressures of 42 and 69 atmospheres, and measurements were made of the displacement of several lines at those pressures. The following is a more detailed discussion of the behaviour of the copper are under pressure that has yet been published. The work has been confined to the region λ = 4000 to λ = 4600 Å. U., and the pressures have ranged from 1 to 203 atmospheres.