Received three letters from MH. Hopes 'awful visitation' left no permanent effect on MH. JH is not impressed by German philosophers. Journey to Hameln to meet JH's cousins Mrs. Groskopff and Mrs. Knipping. Describes country. Visit to Pyrmont and Lackern. Visited aunt Caroline Herschel and Mrs. and Miss Beckedorff in Hanover. Convinced Madame Witte to build third moon model that JH will give to F. L. Chantrey. News of son William Herschel. Composes two hymns. Departure from Hamburg delayed; may miss H. W. M. Olbers in Bremen.

Admiralty wants to adapt observatory at Mauritius for rating ship chronometers in southern hemisphere. Rigorous attention to time determination would benefit meteorological, hydrographic, and astronomical observations, making Mauritius 'a National Center of Reference' for global research.