More Letters of Charles Darwin Volume I Part 8

I ought to have written sooner to say that I am very willing to subscribe 1 pound 1 s.h.i.+lling to the African man (though it be murder on a small scale), and will send you a Post-office-order payable to Kew, if you will be so good as to take charge of it. Thanks for your information about the Antarctic Zoology; I got my numbers when in Town on Thursday: would it be asking your publisher to take too much trouble to send your Botany ["Flora Antarctica," by J.D. Hooker, 1844] to the Athenaeum Club?

he might send two or three numbers together. I am really ashamed to think of your having given me such a valuable work; all I can say is that I appreciate your present in two ways--as your gift, and for its great use to my species-work. I am very glad to hear that you mean to attack this subject some day. I wonder whether we shall ever be public combatants; anyhow, I congratulate myself in a most unfair advantage of you, viz., in having extracted more facts and views from you than from any one other person. I daresay your explanation of polymorphism on volcanic islands may be the right one; the reason I am curious about it is, the fact of the birds on the Galapagos being in several instances very fine-run species--that is, in comparing them, not so much one with another, as with their a.n.a.logues from the continent. I have somehow felt, like you, that an alpine form of a plant is not a true variety; and yet I cannot admit that the simple fact of the cause being a.s.signable ought to prevent its being called a variety; every variation must have some cause, so that the difference would rest on our knowledge in being able or not to a.s.sign the cause. Do you consider that a true variety should be produced by causes acting through the parent? But even taking this definition, are you sure that alpine forms are not inherited from one, two, or three generations? Now, would not this be a curious and valuable experiment (16/1. For an account of work of this character, see papers by G. Bonnier in the "Revue Generale," Volume II., 1890; "Ann. Sc. Nat." Volume XX.; "Revue Generale," Volume VII.), viz., to get seeds of some alpine plant, a little more hairy, etc., etc., than its lowland fellow, and raise seedlings at Kew: if this has not been done, could you not get it done? Have you anybody in Scotland from whom you could get the seeds?

I have been interested by your remarks on Senecia and Gnaphalium: would it not be worth while (I should be very curious to hear the result) to make a short list of the generally considered variable or polymorphous genera, as Rosa, Salix, Rubus, etc., etc., and reflect whether such genera are generally mundane, and more especially whether they have distinct or identical (or closely allied) species in their different and distant habitats.

Don't forget me, if you ever stumble on cases of the same species being MORE or LESS variable in different countries.

With respect to the word "sterile" as used for male or polleniferous flowers, it has always offended my ears dreadfully; on the same principle that it would to hear a potent stallion, ram or bull called sterile, because they did not bear, as well as beget, young.

With respect to your geological-map suggestion, I wish with all my heart I could follow it; but just reflect on the number of measurements requisite; why, at present it could not be done even in England, even with the a.s.sumption of the land having simply risen any exact number of feet. But subsidence in most cases has hopelessly complexed the problem: see what Jordanhill-Smith (16/2. James Smith, of Jordan Hill, author of a paper "On the Geology of Gibraltar" ("Quart. Journ. Geol. Soc." Volume II., page 41, 1846).) says of the dance up and down, many times, which Gibraltar has had all within the recent period. Such maps as Lyell (16/3. "Principles of Geology," 1875, Volume I., Plate I, page 254.) has published of sea and land at the beginning of the Tertiary period must be excessively inaccurate: it a.s.sumes that every part on which Tertiary beds have not been deposited, must have then been dry land,--a most doubtful a.s.sumption.

I have been amused by Chambers v. Hooker on the K. Cabbage. I see in the "Explanations" (the spirit of which, though not the facts, ought to shame Sedgwick) that "Vestiges" considers all land-animals and plants to have pa.s.sed from marine forms; so Chambers is quite in accordance. Did you hear Forbes, when here, giving the rather curious evidence (from a similarity in error) that Chambers must be the author of the "Vestiges": your case strikes me as some confirmation. I have written an unreasonably long and dull letter, so farewell. (16/4. "Explanations: A Sequel to the Vestiges of the Natural History of Creation" was published in 1845, after the appearance of the fourth edition of the "Vestiges,"

by way of reply to the criticisms on the original book. The "K.

cabbage" referred to at the beginning of the paragraph is Pringlea antis...o...b..tica," the "Kerguelen Cabbage" described by Sir J.D. Hooker in his "Flora Antarctica." What Chambers wrote on this subject we have not discovered. The mention of Sedgwick is a reference to his severe review of the "Vestiges" in the "Edinburgh Review," 1845, volume 82, page 1.

Darwin described it as savouring "of the dogmatism of the pulpit" ("Life and Letters," I., page 344). Mr. Ireland's edition of the "Vestiges"

(1844), in which Robert Chambers was first authentically announced as the author, contains (page xxix) an extract from a letter written by Chambers in 1860, in which the following pa.s.sage occurs, "The April number of the 'Edinburgh Review"' (1860) makes all but a direct amende for the abuse it poured upon my work a number of years ago." This is the well-known review by Owen, to which references occur in the "Life and Letters," II., page 300. The amende to the "Vestiges" is not so full as the author felt it to be; but it was clearly in place in a paper intended to belittle the "Origin"; it also gave the reviewer (page 511) an opportunity for a hit at Sedgwick and his 1845 review.)

LETTER 17. TO L. BLOMEFIELD [JENYNS]. Down. February 14th [1845].

I have taken my leisure in thanking you for your last letter and discussion, to me very interesting, on the increase of species. Since your letter, I have met with a very similar view in Richardson, who states that the young are driven away by the old into unfavourable districts, and there mostly perish. When one meets with such unexpected statistical returns on the increase and decrease and proportion of deaths and births amongst mankind, and in this well-known country of ours, one ought not to be in the least surprised at one's ignorance, when, where, and how the endless increase of our robins and sparrows is checked.

Thanks for your hints about terms of "mutation," etc.; I had some suspicions that it was not quite correct, and yet I do not see my way to arrive at any better terms. It will be years before I publish, so that I shall have plenty of time to think of better words. Development would perhaps do, only it is applied to the changes of an individual during its growth. I am, however, very glad of your remark, and will ponder over it.

We are all well, wife and children three, and as flouris.h.i.+ng as this horrid, house-confining, tempestuous weather permits.

LETTER 18. TO J.D. HOOKER. Down [1845].

I hope you are getting on well with your lectures, and that you have enjoyed some pleasant walks during the late delightful weather. I write to tell you (as perhaps you might have had fears on the subject) that your books have arrived safely. I am exceedingly obliged to you for them, and will take great care of them; they will take me some time to read carefully.

I send to-day the corrected MS. of the first number of my "Journal"

(18/1. In 1842 he had written to his sister: "Talking of money, I reaped the other day all the profit which I shall ever get from my "Journal"

["Journal of Researches, etc."] which consisted in paying Mr. Colburn 21 pounds 10 s.h.i.+llings for the copies which I presented to different people; 1,337 copies have been sold. This is a comfortable arrangement, is it not?" He was proved wrong in his gloomy prophecy, as the second edition was published by Mr. Murray in 1845.) in the Colonial Library, so that if you chance to know of any gross mistake in the first 214 pages (if you have my "Journal"), I should be obliged to you to tell me.

Do not answer this for form's sake; for you must be very busy. We have just had the Lyells here, and you ought to have a wife to stop your working too much, as Mrs. Lyell peremptorily stops Lyell.

LETTER 19. TO J.D. HOOKER.

(19/1. Sir J.D. Hooker's letters to Mr. Darwin seem to fix the date as 1845, while the reference to Forbes' paper indicates 1846.)

Down [1845-1846].

I am particularly obliged for your facts about solitary islands having several species of peculiar genera; it knocks on the head some a.n.a.logies of mine; the point stupidly never occurred to me to ask about. I am amused at your anathemas against variation and co.; whatever you may be pleased to say, you will never be content with simple species, "as they are." I defy you to steel your mind to technicalities, like so many of our brother naturalists. I am much pleased that I thought of sending you Forbes' article. (19/2. E. Forbes' celebrated paper "Memoirs of the Geological Survey of Great Britain," Volume I., page 336, 1846. In Lyell's "Principles," 7th Edition, 1847, page 676, he makes a temperate claim of priority, as he had already done in a private letter of October 14th, 1846, to Forbes ("Life of Sir Charles Lyell," 1881, Volume II., page 106) both as regards the Sicilian flora and the barrier effect of mountain-chains. See Letter 20 for a note on Forbes.) I confess I cannot make out the evidence of his time-notions in distribution, and I cannot help suspecting that they are rather vague. Lyell preceded Forbes in one cla.s.s of speculation of this kind: for instance, in his explaining the ident.i.ty of the Sicily Flora with that of South Italy, by its having been wholly upraised within the recent period; and, so I believe, with mountain-chains separating floras. I do not remember Humboldt's fact about the heath regions. Very curious the case of the broom; I can tell you something a.n.a.logous on a small scale. My father, when he built his house, sowed many broom-seeds on a wild bank, which did not come up, owing, as it was thought, to much earth having been thrown over them.

About thirty-five years afterwards, in cutting a terrace, all this earth was thrown up, and now the bank is one ma.s.s of broom. I see we were in some degree talking to cross-purposes; when I said I did [not] much believe in hybridising to any extent, I did not mean at all to exclude crossing. It has long been a hobby of mine to see in how many flowers such crossing is probable; it was, I believe, Knight's view, originally, that every plant must be occasionally crossed. (19/3. See an article on "The Knight-Darwin law" by Francis Darwin in "Nature," October 27th, 1898, page 630.) I find, however, plenty of difficulty in showing even a vague probability of this; especially in the Leguminosae, though their [structure?] is inimitably adapted to favour crossing, I have never yet met with but one instance of a NATURAL MONGREL (nor mule?) in this family.

I shall be particularly curious to hear some account of the appearance and origin of the Ayrs.h.i.+re Irish Yew. And now for the main object of my letter: it is to ask whether you would just run your eye over the proof of my Galapagos chapter (19/4. In the second edition of the "Naturalist's Voyage."), where I mention the plants, to see that I have made no blunders, or spelt any of the scientific names wrongly. As I daresay you will so far oblige me, will you let me know a few days before, when you leave Edinburgh and how long you stay at Kinnordy, so that my letter might catch you. I am not surprised at my collection from James Island differing from others, as the damp upland district (where I slept two nights) is six miles from the coast, and no naturalist except myself probably ever ascended to it. c.u.ming had never even heard of it.

c.u.ming tells me that he was on Charles, James, and Albemarle Islands, and that he cannot remember from my description the Scalesia, but thinks he could if he saw a specimen. I have no idea of the origin of the distribution of the Galapagos sh.e.l.ls, about which you ask. I presume (after Forbes' excellent remarks on the facilities by which embryo-sh.e.l.ls are transported) that the Pacific sh.e.l.ls have been borne thither by currents; but the currents all run the other way.

(PLATE: EDWARD FORBES 1844? From a photograph by Hill & Adamson.)

LETTER 20. EDWARD FORBES TO C. DARWIN.

(20/1. Edward Forbes was at work on his celebrated paper in the "Geological Survey Memoirs" for 1846. We have not seen the letter of Darwin's to which this is a reply, nor, indeed, any of his letters to Forbes. The date of the letter is fixed by Forbes's lecture given at the Royal Inst.i.tution on February 27th, 1846 (according to L. Horner's privately printed "Memoirs," II., page 94.))

Wednesday. 3, Southwark Street, Hyde Park. [1846].

Dear Darwin

To answer your very welcome letter, so far from being a waste of time, is a gain, for it obliges me to make myself clear and understood on matters which I have evidently put forward imperfectly and with obscurity. I have devoted the whole of this week to working and writing out the flora question, for I now feel strong enough to give my promised evening lecture on it at the Royal Inst.i.tution on Friday, and, moreover, wish to get it in printable form for the Reports of our Survey.

Therefore at no time can I receive or answer objections with more benefit than now. From the hurry and pressure which unfortunately attend all my movements and doings I rarely have time to spare, in preparing for publication, to do more than give brief and unsatisfactory abstracts, which I fear are often extremely obscure.

Now for your objections--which have sprung out of my own obscurities.

I do not argue in a circle about the Irish case, but treat the botanical evidence of connection and the geological as distinct. The former only I urged at Cambridge; the latter I have not yet publicly maintained.

My Cambridge argument (20/2. "On the Distribution of Endemic Plants,"

by E. Forbes, "Brit. a.s.soc. Rep." 1845 (Cambridge), page 67.) was this: That no known currents, whether of water or air, or ordinary means of transport (20/3. Darwin's note on transportation (found with Forbes'

letter): "Forbes' arguments, from several Spanish plants in Ireland not being transported, not sound, because sea-currents and air ditto and migration of birds in SAME LINES. I have thought not-transportation the greatest difficulty. Now we see how many seeds every plant and tree requires to be regularly propagated in its own country, for we cannot think the great number of seeds superfluous, and therefore how small is the chance of here and there a solitary seedling being preserved in a well-stocked country."), would account for the little group of Asturian plants--few as to species, but playing a conspicuous part in the vegetation--giving a peculiar botanical character to the south of Ireland; that, as I had produced evidence of the other floras of our islands, i.e. the Germanic, the Cretaceous, and the Devonian (these terms used topographically, not geologically) having been acquired by migration over continuous land (the glacial or alpine flora I except for the present--as ice-carriage might have played a great part in its introduction)--I considered it most probable, and maintained, that the introduction of that Irish flora was also effected by the same means.

I held also that the character of this flora was more southern and more ancient than that of any of the others, and that its fragmentary and limited state was probably due to the plants composing it having (from their comparative hardiness--heaths, saxifrages, etc.) survived the destroying influence of the glacial epoch.

My geological argument now is as follows: half the Mediterranean islands, or more, are partly--in some cases (as Malta) wholly--composed of the upheaved bed of the Miocene sea; so is a great part of the south of France from Bordeaux to Montpellier; so is the west of Portugal; and we find the corresponding beds with the same fossils (Pecten latissimus, etc.) in the Azores. So general an upheaval seems to me to indicate the former existence of a great post-Miocene land [in] the region of what is usually called the Mediterranean flora. (Everywhere these Miocene islands, etc., bear a flora of true type.) If this land existed, it did not extend to America, for the fossils of the Miocene of America are representative and not identical. Where, then, was the edge or coast-line of it, Atlantic-wards? Look at the form and constancy of the great fucus-bank, and consider that it is a Sarga.s.sum bank, and that the Sarga.s.sum there is in an abnormal condition, and that the species of this genus of fuci are essentially ground-growers, and then see the probability of this bank having originated on a line of ancient coast.

Now, having thus argued independently, first on my flora and second on the geological evidences of land in the quarter required, I put the two together to bear up my Irish case.

I cannot admit the Sarga.s.sum case to be parallel with that of Confervae or Oscillatoria.

I think I have evidence from the fossils of the boulder formations in Ireland that if such Miocene land existed it must have been broken up or partially broken up at the epoch of the glacial or boulder period.

All objections thankfully received.

Ever most sincerely,

EDWARD FORBES.

LETTER 21. TO L. JENYNS (BLOMEFIELD). Down. [1846].

I am much obliged for your note and kind intended present of your volume. (21/1. No doubt the late Mr. Blomefield's "Observations in Natural History." See "Life and Letters," II., page 31.) I feel sure I shall like it, for all discussions and observations on what the world would call trifling points in Natural History always appear to me very interesting. In such foreign periodicals as I have seen, there are no such papers as White, or Waterton, or some few other naturalists in Loudon's and Charlesworth's Journal, would have written; and a great loss it has always appeared to me. I should have much liked to have met you in London, but I cannot leave home, as my wife is recovering from a rather sharp fever attack, and I am myself slaving to finish my S.

American Geology (21/2. "Geological Observations in South America"

(London), 1846.), of which, thanks to all Plutonic powers, two-thirds are through the press, and then I shall feel a comparatively free man.

Have you any thoughts of Southampton? (21/3. The British a.s.sociation met at Southampton in 1846.) I have some vague idea of going there, and should much enjoy meeting you.

LETTER 22. TO J.D. HOOKER. Shrewsbury [end of February 1846].