Dear Darwin,

Though you interdict a rejoinder to your letter, yet as you have been at the trouble of writing to express your satisfaction with the articles you name, I cannot consent to let your letter pass without saying how much gratified I am by your approval.¹ I should very well have liked, had time permitted, to deal somewhat more fully with the metaphysical part of M^r. Martineau’s argument. If, as I expect him to do, he makes some reply, it will probably furnish the occasion, after an interval, for a fuller exposition; by which I hope to make clear to quite ordinary apprehensions, the absolute emptiness of all such propositions as that with which M^r. Martineau deludes himself & his readers.

I am glad to hear you have got through your book on “Expression”, & that (as I gathered from M^r. Tylor at the Athenæum the other day) you are in good condition notwithstanding your work.²

My own lucubrations on the same topic are also finished, & will appear in the forthcoming number of the Psychology, which you will probably find waiting for you when you get back to Down.³

very sincerely yours | Herbert Spencer