On the dark lines of oxygen in the solar spectrum on the less refrangible side of G

Abstract

IN a paper on the lines of oxygen, published in this Journal for October, 1878, the solar lines closely coincident with those of the eleetric spectrum of oxygen were given. The measurements of the solar lines in that instance were taken from photographs made in March, 1878. Since that time, under more favorable atmospheric conditions, I have succeeded in obtaining finer photographs on the less refrangible side of G. These show many faint lines, not visible in the photographs of March 1878, while many other lines are distinctly sub-divided. Three of the recent photographs were taken on the same day, during the last week in November, and two have been taken since that time i one during the last week in January, and one during the first week in Febmary. In all five of these photographs faint lines are visible between ,l. 4316 and ,l. 4320, of Angtsrom's scale, and they all show them in the position indicated by the diagram and table. The fact that aU the photographs agree iu their representation of these lines, is, I think, proof positive of the correctness of the positions assigned.