JH has got hold of the explanation about central forces. Need not worry about Elizabeth Baily; he will see to that. Do not reject any letters; they may be important in the future. Gives one of his own theorems.

Birth of his sixth son [C. W. Darwin]. It is dreadful "to think of all the sendings to school and the professions afterwards".

CD is not well but has not the courage for water-cure again; trying mineral acids.

Working hard on the book [Natural selection]; is overwhelmed with riches in facts and interested in way facts fall into groups.

To his surprise [Helix pomatia] has withstood 14 days in salt water.

Pigeons’ skins come in from all parts of the world.