An earlier paper entitled "Notes on the Effects produced by the ancient Glaciers of Caernarvonshire, and on the Boulders transported by floating Ice" ("Phil. Mag." 1842, page 352) is spoken of by Sir Archibald Geikie as standing "almost at the top of the long list of English contributions to the history of the Ice Age" ("Charles Darwin," "Nature" Series, page 23).), and Scientific Geological Instructions for the Admiralty Volume (27/3. "A manual of Scientific Enquiry, prepared for the use of Her Majesty's Navy, and adapted for Travellers in General." Edited by Sir John F.W. Herschel, Bart. Section VI.--Geology--by Charles Darwin. London, 1849. See "Life and Letters," pages 328-9.), which cost me some trouble. This work, which is edited by Sir J. Herschel, is a very good job, inasmuch as the captains of men-of-war will now see that the Admiralty cares for science, and so will favour naturalists on board. As for a man who is not scientific by nature, I do not believe instructions will do him any good; and if he be scientific and good for anything the instructions will be superfluous. I do not know who does the Botany; Owen does the Zoology, and I have sent him an account of my new simple microscope, which I consider perfect, even better than yours by Chevalier. N.B. I have got a 1/8 inch object-glass, and it is grand. I have been getting on well with my beloved Cirripedia, and get more skilful in dissection. I have worked out the nervous system pretty well in several genera, and made out their ears and nostrils (27/4. For the olfactory sacs see Darwin's "Monograph of the Cirripedia," 1851, page 52.), which were quite unknown. I have lately got a bisexual cirripede, the male being microscopically small and parasitic within the sack of the female. I tell you this to boast of my species theory, for the nearest closely allied genus to it is, as usual, hermaphrodite, but I had observed some minute parasites adhering to it, and these parasites I now can show are supplemental males, the male organs in the hermaphrodite being unusually small, though perfect and containing zoosperms: so we have almost a polygamous animal, simple females alone being wanting. I never should have made this out, had not my species theory convinced me, that an hermaphrodite species must pass into a bisexual species by insensibly small stages; and here we have it, for the male organs in the hermaphrodite are beginning to fail, and independent males ready formed. But I can hardly explain what I mean, and you will perhaps wish my barnacles and species theory al Diavolo together. But I don't care what you say, my species theory is all gospel. We have had only one party here: viz., of the Lyells, Forbes, Owen, and Ramsay, and we both missed you and Falconer very much...I know more of your history than you will suppose, for Miss Henslow most good-naturedly sent me a packet of your letters, and she wrote me so nice a little note that it made me quite proud. I have not heard of anything in the scientific line which would interest you. Sir H. De la Beche (27/5. The Presidential Address delivered by De la Beche before the Geological Society in 1848 ("Quart. Journ. Geol. Soc." Volume IV., "Proceedings," page xxi, 1848).) gave a very long and rather dull address; the most interesting part was from Sir J. Ross. Mr. Beete Jukes figured in it very prominently: it really is a very nice quality in Sir Henry, the manner in which he pushes forward his subordinates. Jukes has since read what was considered a very valuable paper. The man, not content with moustaches, now sports an entire beard, and I am sure thinks himself like Jupiter tonans. There was a short time since a not very creditable discussion at a meeting of the Royal Society, where Owen fell foul of Mantell with fury and contempt about belemnites. What wretched doings come from the order of fame; the love of truth alone would never make one man attack another bitterly. My paper is full, so I must wish you with all my heart farewell.

Charles Darwin

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