Letter from G [George] Johnstone Stoney, 8 Upper Hornsey Rise, to [Joseph] Larmor He has just returned from Dublin, where [George] Fitzgerald told him that Larmor was trying to trace the lines of an element's specturm to a dynamical source. Stoney sends his paper on a possible cause of double lines, together with a table of oscillation frequencies [not present]. He offers advice on the best use of the table, and recommends Colonel [William Henry] Oakes's tables of reciprocals. He also sends an attempt to reduce the sodium spectrum. He wishes he had a copy of a paper in the 1871 Philosophical Magazine for its 'very curious' relationship between the intensities of the absorption spectrum of chlorochromic anhydride and the intensities of the Fourier series representing the motion of a point on a violin string. This vapour's series of lines is a long one and despite the paper, Stoney does not think it truly harmonic, drawing Larmor's attention to other references pertinent to the subject. In a postscript, Stoney recommends Rowland's determinations of solar wavelengths in air for accuracy, rather than Angstrom's. 29 July 1894