<span>Darwin writes to Bates to thank him for an interesting letter. Darwin notes that his belief is that a good observer is also a good theorist. He is also enthused in H. W. Bates writing on 'equatorial refrigeration'. Transcription: "My dear Sir, I thank you sincerely for writing to me and for your very interesting letter. Your name has for very long been familiar to me, and I have heard of your zealous exertions in the cause of Natural History. But I did not know that you had worked with high philosophical questions before your mind. I have an old belief that a good observer really means a good theorist and I fully expect to find your observations most valuable. I am very sorry to hear that your health is shattered; but I trust under a healthy climate it may be restored. I can sympathise with you fully on this score, for I have had bad health for many years and fear I shall ever remain a confirmed invalid. I am delighted to hear that you, with all your large practical knowledge of Nat. History, anticipated me in many respects and concur with me. As you say I have been thoroughily well attacked and reviled, (especially by entomologists, [J. O.] Westwood, [T. V.] Wollaston, and [Andrew] Murray have all reviewed and sneered at me to their hearts' content) but I care nothing about their attacks; several really good judges go a long way with me, and I observe that all those who go some little way tend to go somewhat further. What a fine philosophical mind your friend, Mr Wallace has, and he has acted in relation to me, like </span><span>a true man with a noble spirit. I see by your letter that you have grappled with several of the most difficult problems, as it seems to me, in natural History— such as the distinctions between the different kinds of varieties, representative species Perhaps I shall find some facts in your paper on intermediate varieties in intermediate regions, on which subject I have found remarkably little information. I cannot tell you how glad I am to hear that you have attended to the curious point of Equatorial refrigeration. I quite agree that it must have been small; yet the more I go into that question the more convinced I feel that there was during the Glacial period some migration from N. to S. The sketch in the Origin gives a very meagre account of my fuller M.S. Essay on this subject. I shall be particularly obliged for a copy of your paper when published; and if any suggestions occur to me (not that you require any) or questions I will write and ask. Pray believe me, with respect and good wishes, My dear Sir, Yours sincerely, C. Darwin I have at once to prepare a new Edit of the Origin, and I will do myself the pleasure of sending you a copy; but it will be only very slightly altered. Cases of neuter ants, divided into castes, with intermediate gradations. (which I imagine are rare) interest me much. V. Origin on the Driver Ants p.—241.— (please look at the passage)" Letter, signed by sender. Sent from Down House, near Beckenham, Kent, England.The Robert M. Stecher Collection of Charles Darwin Books and Manuscripts</span>
