Discusses papers by JC dealing with erosion. Comments on papers on the subject by J. B. Jukes, A. C. Ramsay, and William Whitaker. Formerly believed in power of the sea. Never fully realised the truth until reading JC’s papers.

Comments on glaciers in North America.

Asks if glacial periods have occurred alternately in the Northern and Southern Hemispheres. Relevant to his glacial discoveries in South America: "it would have been an immense relief to my mind if I could have assumed … this". CD wishes to discuss subject in new edition of Origin [5th].

Acknowledges receipt of book and manuscript.

Apologises for having kept JC’s book so long; would like to keep it about ten days more.

Returns book with thanks. "Joyfully accepts" idea of the warming of Southern Hemisphere during glacial period in the Northern. Lyell is unwilling.

Mentions H. N. Moseley’s study of descent of glaciers [Proc. R. Soc. Lond. 17 (1869): 202–8].

CD greatly troubled by problem of age of the earth and calculations of Sir William Thomson. Asks about changes in the form of the globe.

Consoling to CD that JC gives "a little more age to the world".

Cites article by Henry Moseley ["On the mechanical possibility of the descent of glaciers", Proc. R. Soc. Lond. 17 (1869): 202–8].

Mentions article by A. R. Clarke on shape of the globe.

Thanks JC for his proofs of article on the movement of glaciers.