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Darwin Correspondence Project

To J. D. Hooker   [3 September 1846]

Down Farnborough Kent


My dear Hooker

I hope this letter will catch you at Clifton, but I have been prevented writing by being unwell & having had the Horner’s here as visitor, which with my abominable press-work has fully occupied my time. It is, indeed, a long time since we wrote to each other; though, I beg to tell you, that I wrote last, but what about I cannot remember, except, I know, it was after reading your last numbers, & I sent you a uniquely laudatory epistle, considering that it was from a man who hardly knows a daisy from a Dandelion to a professed Botanist.— By the way I announced Hopkirk’s book being sent back, did it reach you?—

I was very glad to hear what you were about; but I fear you must feel your time rather thrown away.— I cannot remember, what papers have given me the impression, but I have that, which you state to be the case, firmly fixed on my mind, namely the little chemical importance of the soil to its vegetation.— What a strong fact it is, as R Brown once remarked to me, of certain plants being calcareous ones here which are not so under a more favourable climate on the continent, or the reverse, for I forget which; but you no doubt will know to what I refer.— By the way there are some such cases in Herbert’s paper in Hort. Journal:1 have you read it, it struck me as extremely original & bears directly on your present researches.— To a non-botanist the Chalk has the most peculiar aspect of any flora in England; why will you not come here & make your observations? We go to Southampton, if my courage & stomach do not fail, for the Brit. Assoc: (do you not consider it your duty to be there?), & why cannot you come here afterwards & work. I expect Sulivan here the first week in October & I hope to get a few more here, & how glad we should be if you cd come then or at any time whatever.—

Before the end of the month, I shall have quite finished my S. American Geology, & extremely glad I shall be, for I have been pushing on & feeling jaded for the last several months by it.—

I am astonished (having felt a curiosity on the point) at the number of species on 2 square yards (or two yards square?); though I cannot read whether it is 26 or 16 to 48 species; does this include cryptogams: if you do not publish this, I shd like much sometime to hear more particulars about this; if you publish, where will it be?2

I am much pleased to hear you have worked out the identical & representative species of N. temperate & Antarctic regions & shall be exceedingly glad to see it; but as it of course will be published, I will not think of troubling you to send it me: I hope you will add, whenever you know, whether species of the same genera are found in the intermediate tropical districts, saying, whether in America or elsewhere, whether on high-lands or lowlands; this no doubt wd add to your trouble, even if you gave only such information as you possessed without search, & surely it wd add great interest to your results: Mr. Gardener’s list of Mountain Brazil plants3 wd thus come incidentally in, as indeed wd lists from all parts of the world.

I have not yet seen Forbe’s memoir,4 but have ordered it, & will enjoy writing to you my opinion. I am very sorry to hear what you say about Watson’s previous work; I feel sure that Forbe’s own noble indifference to fame is the main cause of his not in some instances making proper acknowledgment.— Horner (private) tells me that he has just remonstrated with him, for not having mentioned Lyell’s views on climatic changes, & his answer was,—“I shd as soon have thought it necessary to refer to Linnæus, as originator of specific characters”.—& I have no doubt this is the simple truth.—5 I cannot remember whether I have ever read (except a few papers) any of Watson’s works: could you sometime lend me the chief? I shd. much like to see them.

I am almost sorry for your eternal additional labours on the Galapagos Flora; though as yet your work assuredly has not been thrown away, as many have referred to your curious geographical results on this archipelago.— I suppose you feel sure that Edmonston’s Collections from the mainland have not been mingled with those of the Galapagos—6

Have you ever thought of G. St. Hilaire “loi du balancement”, as applied to plants: I am well aware that some zoologists quite reject it, but it certainly appears to me, that it often holds good with animals.— You are no doubt aware of the kind facts I refer to, such as great development of canines in the carnivora apparently causing a diminution—a compensation or balancement—in the small size of premolars &c &c.—7 I have incidentally noticed some analogous remarks on plants, but have never seen it discussed by Botanists.— Can you think of cases of any one species in genus, or genus in family, with certain parts extra developed, & some adjoining parts reduced? In varieties of same species, double flowers & large fruits seem something of this,—want of pollen & of seeds balancing with the increased number of petals & development of fruit.—

—I hope we shall see you here this autumn, & I will let you know when Sulivan comes—or anytime will suit us.

Ever my dear Hooker | Most truly yours | C. Darwin

Do you know whether Dieffenbach is in London, & where?

P.S. | (I do not quite understand, do you intend giving up the Museum of Economic Geology altogether? I know it is private:— I sh⁠⟨⁠d be⁠⟩⁠ almost glad of it.—)


W. Herbert 1846.
Although it is not clear to what Hooker’s figures apply, CD’s interest was probably aroused by the evidence they provided for the diversity of vegetation in small areas and under uniform conditions of life. Such evidence became important to CD in support of his principle that the maximum diversity of living beings permits the maximum amount of organic life in any area, and the corollary that natural selection, by tending to maximise the amount of organic life, will also tend to maximise the diversity of organic beings. These ideas formed the basis of CD’s principle of divergence as elaborated in Natural selection (pp. 227–51) and the Origin.
Gardner 1846.
Charles Lyell evidently thought Edward Forbes’s reply was ‘sufficient’ and had no wish to enter into controversy with Forbes, see K. M. Lyell ed. 1881, 2: 105–13.
CD refers to Hooker’s comment that Thomas Edmondston’s Galápagos collection contained some mainland species from Guayaquil, see letter from J. D. Hooker, [before 3 September 1846].


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.

Natural selection: Charles Darwin’s Natural selection: being the second part of his big species book written from 1856 to 1858. Edited by R. C. Stauffer. Cambridge: Cambridge University Press. 1975.

Origin: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. By Charles Darwin. London: John Murray. 1859.


Has nearly finished South America.

Pleased to hear JDH has worked out identical and representative species of N. Temperate and Antarctic regions.

Geoffroy Saint Hilaire’s "loi du balancement" as applied to plants.

CD jaded by, but has nearly completed, South America.

Letter details

Letter no.
Charles Robert Darwin
Joseph Dalton Hooker
Sent from
Source of text
DAR 114: 64
Physical description
ALS 5pp

Please cite as

Darwin Correspondence Project, “Letter no. 996,” accessed on 29 September 2023,

Also published in The Correspondence of Charles Darwin, vol. 3