Origin of Antarctic brash ice.
Further on case of Lycopodium: does JDH know any genera of plants whose species are variable in one continent but not in another? Discussion on variations between floras as regards species richness, and factors affecting geographical distribution. On species, CD expects "that I shall be able to show even to sound naturalists that there are two sides to the question of the immutability of species; – that facts can be viewed and grouped under the notion of allied species having descended from common stocks". Mentions books and papers for and against species mutability. CD believes past absurd ideas arose from no one's having approached subject on side of variation under domestication.
Would like to see Clarke's paper
and would welcome visit from JDH.
Down Bromley Kent
My dear Hooker
I had intended writing to you today, had I not received yesterday's enclosure to remind me. Many thanks for the seed & for sending me your curious account of the antarctic ice, which no doubt, together with your notes on Infusoria, Ehrenberg wd be very glad to see.— I sent my last parcel through Mr Taylor of Fleet St. or rather, (I believe) through Mr Francis, who lives with him.— The homogeneous manner in which the brash is coloured, certainly appears very curious; I presume you consider the quantity too great for snow; with respect to its rising from the bottom, I shd rather doubt it, though in fresh running water, it is well known that icy matter, I suspect like your brash, rises from the bottom, & brings with it stones. There has been much argument about cause of this, in which even Arago has joined: the best explanation offered, as it appeared to me, was that the bottom of the stream lost its heat by radiation & and the water froze on it. Should you feel much interest on this subject, I could look you up, (I think) some references. One wd doubt, whether the bottom of the sea would lose its heat by radiation through several hundred feet of thickness of water, & the whole body of water would have to be cooled to the freezing point of sea-water. On other hand Simpson & Deane (I think) found the bottom of shallow arctic sea hard frozen: off Spitzbergen masses of ice suddenly rise from the bottom, I have fancied they were remnants of fixed & grounded icebergs.
What a curious, wonderful case is that of the Lycopodiums; I suppose you would hardly have expected them to be more varying than a phanerogamic plant. I trust you will work the case out & even if unsupported publish it, for you can surely do this with due caution. I have heard of some analogous facts, though on the smallest scale, in certain insects being more variable in one district than in another; & I think the same holds with some land-shells. By a strange chance, I had noted to ask you in this letter an analogous question, with respect to genera, in lieu of individual species —that is, whether you know of any case of a genus with most of its species being variable (say Rubus) in one continent, having another set of species in another continent non-variable or not in so marked a manner. Mr Herbert incidentally mentioned in a letter to me, that the Heaths at the C. of Good Hope were very variable, whilst in Europe they are (?) not so (?); but then the species here are few in comparison, so that the case, even if true, is not a good one.— In some genera of insects the variability appears to be common in distant parts of the world: in shells, I hope hereafter, to get much light on this question through fossils. If you can help me, I shd be very much obliged: indeed all your letters are most useful to me.
Monday— Now for your first long letter & to me quite as interesting
as long. Several things are quite new to me in it, viz for one, your belief that there
are more extra-tropical than intratropical species. I see that my argument from the
Arctic regions is false, & I shd not have tryed to argue against
you, had I not fancied that you thought that equability of climate was the
direct cause of the creation of a greater or lesser number of species: I see
you call our climate equable, I shd have thought it was the contrary;
anyhow the term is vague, & in England will depend upon whether a person
compares it with the United States or T. del Fuego.— In my Journal,
(p. 342) I see I state that in South Chiloe at height of about 1000 ft
the forest had a Fuegian aspect: I distinctly recollect, that at sea-level in middle of
Chiloe, the forest had almost a tropical aspect. I
I shd be much obliged for a loan of the Tasmanian Journal with
Revd: Clarke's Paper: I suspect, however, it will turn out to
be the same with a paper read by him before the Geolog: Soc: on the same
subject.— I shall be in town on the
Is there any chance of your being able to pay us a visit here soon; it would give
Once again, thanks for your Botanical letters & believe me, my dear Hooker, | Very truly yours | C. Darwin
Will you tell Sir William, that the Deodar, which he gave me, is doing famously.
I am really ashamed how infamously this letter is written.—
- f1 789.f1Brash-ice, fragments of crushed ice.
- f2 789.f2Arago 1833.
- f3 789.f3Dease and Simpson 1838, pp. 218, 220.
- f4 789.f4See CD's annotations to the letter from J. D. Hooker, 28 October 1844.
- f5 789.f5CD was to repeat this question to Hooker and other naturalists. For example, on 28 December 1853, CD noted:
Hooker went through the N. Zealand & Tasmanian Flora, & he thinks that all the genera which are variable in Europe are quite as variable in these localities. Hence I must [‘clearly’ del ] give up this kind of generic variability, as any aid in transmutation (DAR 45: 5).
- f6 789.f6See Correspondence vol. 2, letter from William Herbert, [c. 27 June 1839].
- f7 789.f7CD met Alexander von Humboldt in January 1842 and made the following note:
Jan. 29t h. /42/. Humboldt descanted on remarkable fact (as observed by Gmelin & Pallas) that the *banks of the [interl ] River Oby separates two Floras—on one side 810 of plants same as in Germany with 210 Asiatic—on other side reversed large proportion of Asiatic.— Remarked a similar case with respect to the distribution of oaks in some place, I did not catch up—with Astacus in all the brooks on one side & not on the other: says Bellis perennis extends to a certain limit & then ceases, but it is not the cold, for this plant will flower, [‘far’ del ] within the limits of snow on some mountains— On the Oby there is no geological change——prepossession *of soil [interl ] must here have done much.— [reverse question mark].Have two Floras marched from opposite sides & met here??—strange case.— (DAR 100: 167).
- f8 789.f8Annotations on CD's copy of C. Lyell 1837 (Darwin Library–CUL) are discussed in S. Smith 1960.
- f9 789.f9CD's copy of Prichard 1836–7 is annotated (Darwin Library–CUL).
- f10 789.f10Agassiz 1842.
- f11 789.f11CD's copy of I. Geoffroy Saint-Hilaire 1841 is annotated (Darwin Library–CUL).
- f12 789.f12Lamarck 1815–22. CD's copies of this and the second edition (Lamarck 1835–45) are in the Darwin Library–CUL.
- f13 789.f13CD's copy of Lamarck 1830 (volume one only) is in the Darwin Library–CUL. This particular opinion is not found there, but see pp. 223, 235, and 268, where CD has marked Lamarck's discussion of insect reproduction. See also Notebook C: 63.
- f14 789.f14Clarke 1842, which was a longer version of a paper read to the Geological Society in 1839 (Clarke 1839).