Thanks RM for "Dynamics of earthquakes" [Trans. R. Irish Acad. 21 (1848): 50–106]. It has cleared up his ideas on undulations. Now wishes he had said nothing about them in Journal of researches. Sends his paper ["Certain volcanic phenomena in S. America", Collected papers 1: 53–86]. Wishes RM would investigate Chile. Speculates whether earthquakes coincide with moon or tides.