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Darwin Correspondence Project

From J. D. Hooker   7 August 1866


Aug. 7th/66

Dear old Darwin

You must not let me worry you. I am an obstinate pig—but you must not be miserable at my looking at the same thing in a different light from you—1 I must get to the bottom of this question—& that is all I can do— some clever fellow one day will knock the bottom out of it, & see his way to explain what to a Botanist without a theory to support must be very great difficulties— True enough, all may be explained as you reason it will be, I quite grant this: but meanwhile all is not so explained, & I cannot accept a hypothesis that leaves so many facts unaccounted for.—2

You say temp. parts of N. Am nearly 212 times as distant from Azores as Europe is. According to a rough calculation on Col James’ chart I make

East. Azores to Portugal 850 West do to N. F. Land 15003

but I am writing to a friend at Admiralty to have the distance calculated (which looks like cracking nuts with Nasmyth’s hammer!—4

Are European birds blown to America?

Are the Azorean erratics an established fact? I want them very badly, though they are not of much consequence, as a slight sinking would hide all evidence of that sort.5

I do want to sum up impartially, leaving verdict to jury, I cannot do this without putting all difficulties most clearly— how do you know how you would fare with me if you were a continentalist!— Then too we must recollect that I have to meet a host who are all on the continental side, in fact pretty nearly all the thinkers, Forbes, Hartung, Heer, Unger, Wollaston, Lowe, (Wallace I suppose) & now Andrew Murray.6 I do not regard all these, & snap my fingers at all but you: in my inmost soul I conscientiously say I incline to your theory—but I cannot accept it as an established truth, or unexceptionable hypothesis.

The “Wire bird” being a grallator is a curious fact favorable to you.7 Sclater never heard of it.8 How I do yearn to go out again to St Helena.9

Ever yrs affec | J D Hooker

Of course I accept the Ornithological evidence as tremendous strong—though why they should get blown Westerly, & not changed specifically as Insects shells & plants have done, is a mystery.10

CD annotations

8.1 though … specifically 8.2] triple scored pencil


Hooker and CD had been debating since Hooker’s letter of [24 July 1866] the means by which oceanic islands had become populated by plants. Hooker was preparing a lecture for the meeting of the British Association for the Advancement of Science at Nottingham in August 1866. Hooker refers to CD’s hypothesis of occasional trans-oceanic transport (see letter to J. D. Hooker, 30 July [1866] and n. 7).
See letter to J. D. Hooker, 5 August [1866] and n. 5. Hooker used a new map of the earth by Henry James to illustrate his lecture (see n. 2, above). See also letter to J. D. Hooker, 30 June [1866] and n. 6.
The industrial steam hammer was commonly known as Nasmyth’s hammer, after James Hall Nasmyth, who designed the prototype in 1839 (ODNB).
See letter to J. D. Hooker, 5 August [1866] and n. 6. Hooker refers to the possibility that erratic boulders deposited by icebergs on islands might later be submerged owing to subsidence.
According to Edward Forbes, continental Europe formerly included Britain; southern Ireland and Portugal were once connected by land; and the western parts of Europe and north Africa had extended far into the Atlantic encompassing the Canary Islands, Madeira, and the Azores (Forbes 1846). Oswald Heer proposed that Madeira, the Canaries, Porto Santo, and the Azores were the remnants of a sunken land-mass, or ‘Atlantis’, that in the Tertiary period had been connected to America and Europe by a land-bridge (Heer 1855). Franz Unger, Thomas Vernon Wollaston, and Andrew Murray also promoted the theory of continental extension in their writings (see, for example, Wollaston 1856, Unger 1860, and Murray 1866). Alfred Russel Wallace had considered the possibility that land connections had existed between neighbouring countries now separated by sea (A. R. Wallace 1857). For Wallace’s summary of the difference between his and CD’s views on geographical distribution, see A. R. L. Wallace 1905, 2: 20–1. Hooker also refers to Georg Hartung and Richard Thomas Lowe, who had worked on the geology and natural history of the Atlantic Islands (see, for example, Hartung 1864 and Lowe 1868).
Hooker accepted CD’s claim that the wire bird was not a land bird (see letter to J. D. Hooker, 5 August [1866] and n. 2); in his lecture, he stated that there were no land birds on St Helena (J. D. Hooker 1866a, p. 75).
Hooker visited St Helena while returning from the Antarctic expedition aboard HMS Erebus in 1843 (L. Huxley ed. 1918, 1: 96–9; R. Desmond 1999, pp. 30–4, 84). Between 1843 and 1845, CD and Hooker had corresponded about the flora of St Helena in comparison with that of the Galápagos Islands (Correspondence vols. 2 and 3).
In his letter of 5 August [1866], CD recollected seeing several European species of birds in the Azores but said that he had not found any ‘note about Birds being blown to the Azores from Europe’. In the same letter, CD referred Hooker to Origin 3d ed., p. 422, on the land birds of Madeira being derived from Europe and Africa. On the same page, to which Hooker apparently refers, CD contrasted Madeira’s lack of indigenous birds with its richness in indigenous species of land shells. For more on the indigenous insects and plants of Madeira, and their variations among the islands of the archipelago, see Wollaston 1857 and Lowe 1868.


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 28 vols to date. Cambridge: Cambridge University Press. 1985–.

Desmond, Ray. 1999. Sir Joseph Dalton Hooker, traveller and plant collector. Woodbridge, Suffolk: Antique Collectors’ Club with the Royal Botanic Gardens, Kew.

Forbes, Edward. 1846. On the connexion between the distribution of the existing fauna and flora of the British Isles, and the geological changes which have affected their area, especially during the epoch of the Northern Drift. Memoirs of the Geological Survey of Great Britain, and of the Museum of Economic Geology in London 1: 336–432.

Hartung, Georg. 1864. Geologische Beschreibung der Inseln Madeira und Porto Santo. Leipzig: W. Engelmann.

Heer, Oswald. 1855. Ueber die fossilen Pflanzen von St. Jorge in Madeira. [Read 5 November 1855.] Neue Denkschriften der allgemeinen Schweizerischen Gesellschaft für die gesammten Naturwissenschaften n.s. 5 (1857): paper 2.

Lowe, Richard Thomas. 1868. A manual flora of Madeira and the adjacent islands of Porto Santo and the Desertas. Vol. 1, Dichlamydeæ. London: John van Voorst.

Murray, Andrew. 1866. The geographical distribution of mammals. London: Day and Son.

ODNB: Oxford dictionary of national biography: from the earliest times to the year 2000. (Revised edition.) Edited by H. C. G. Matthew and Brian Harrison. 60 vols. and index. Oxford: Oxford University Press. 2004.

Origin 3d ed.: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. 3d edition, with additions and corrections. By Charles Darwin. London: John Murray. 1861.

Unger, Franz. 1860. I. Die versunkene Insel Atlantis. II. Die physiologische Bedeutung der Pflanzencultur. Zwei Vorträge gehalten im Ständehause im Winter des Jahres 1860. Vienna: Wilhelm Braumüller.

Wallace, Alfred Russel. 1857. On the natural history of the Aru Islands. Annals and Magazine of Natural History 2d ser. 20, suppl.: 473–85.

Wallace, Alfred Russel. 1905. My life: a record of events and opinions. 2 vols. London: Chapman & Hall.

Wollaston, Thomas Vernon. 1856. On the variation of species with especial reference to the Insecta; followed by an inquiry into the nature of genera. London: John van Voorst.

Wollaston, Thomas Vernon. 1857. Catalogue of the coleopterous insects of Madeira in the collection of the British Museum. London: By order of the Trustees.


Is attempting to sum up the two theories impartially and must raise all the difficulties with each. More on his differences with CD.

Letter details

Letter no.
Joseph Dalton Hooker
Charles Robert Darwin
Sent from
Source of text
DAR 102: 91–2
Physical description
ALS 4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 5183,” accessed on 20 May 2022,

Also published in The Correspondence of Charles Darwin, vol. 14