My dear Darwin,

I will now begin as I told you I would, to write down my remarks on your book, tho‘ I dare say it may be some time before I finish them.¹ I must begin by saying, more explicitly than when I met you the other day, how much I admire your book.² The astonishing labour & patience with which you must have collected the materials during so many years; the wide range of reading as well as observation; the skill with which the facts are brought to bear on your argument; the extraordinary power of condensation by which so much matter is brought within the compass of a single volume; the candour with which you have tried at least to state the case fairly against yourself; as well as the extreme ingenuity of your theory; all these qualities undoubtedly render your book (Whether its theory be ultimately established or no) one of the most important that have ever appeared on Natural History.

It is moreover no small triumph to your cause, that you have already made converts of the greatest geologist & the greatest botanist of our day.³ Nevertheless you will not be surprised at my saying, that I am not convinced.⁴ In the first place, as I told you the other day, I cannot feel satisfied till I see your “Pièces Justificatives’—the body of evidence which you are to bring forward in your big book. Not that I have not perfect confidence in your accuracy & honesty, but the same facts