As I see from a notice of the proceedings of the Academy of Sciences, Paris, in last week's NATURE (p. 287), that MM. Edouard Sarasin and Lucien de la Rive have observed the fact that “multiple resonance” can be obtained by using different sized resonators with a Hertzian “vibrator,” I adjoin the following short account of experiments of a somewhat different character made during last autumn, which have led to the same results, and which were brought before the notice of the Dublin University Experimental Association last November. Since then I have learnt what these experimenters also seem not to have known—that some of Hertz's earlier experiments were more especially concerned with this very fact.