Letter from Geo Fras [George Francis] Fitzgerald, 7 Ely Place, Dublin, to [Joseph] Larmor Fitzgerald is sending a copy of one of [Thomas] Preston's photographs, showing violet lines of cadmium and a corresponding line of zinc. Each is photographed twice, once with the magnet off and once on. He describes these and how they were taken. He wonders if the different line behaviour might be explained by the vibrations not being possible in all directions around a molecule. Preston is getting more magnetic power and should get important results. 17 December 1897